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>.
6 This file is part of GCC.
8 GCC is free software; you can redistribute it and/or modify
9 it under the terms of the GNU General Public License as published by
10 the Free Software Foundation; either version 3, or (at your option)
13 GCC is distributed in the hope that it will be useful,
14 but WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 GNU General Public License for more details.
18 You should have received a copy of the GNU General Public License
19 along with GCC; see the file COPYING3. If not see
20 <http://www.gnu.org/licenses/>. */
24 #include "coretypes.h"
29 #include "basic-block.h"
30 #include "tree-flow.h"
31 #include "tree-pass.h"
32 #include "tree-dump.h"
34 #include "tree-pretty-print.h"
35 #include "gimple-pretty-print.h"
36 #include "diagnostic-core.h"
39 #include "tree-scalar-evolution.h"
40 #include "tree-ssa-propagate.h"
41 #include "tree-chrec.h"
42 #include "gimple-fold.h"
47 /* Type of value ranges. See value_range_d for a description of these
49 enum value_range_type { VR_UNDEFINED, VR_RANGE, VR_ANTI_RANGE, VR_VARYING };
51 /* Range of values that can be associated with an SSA_NAME after VRP
55 /* Lattice value represented by this range. */
56 enum value_range_type type;
58 /* Minimum and maximum values represented by this range. These
59 values should be interpreted as follows:
61 - If TYPE is VR_UNDEFINED or VR_VARYING then MIN and MAX must
64 - If TYPE == VR_RANGE then MIN holds the minimum value and
65 MAX holds the maximum value of the range [MIN, MAX].
67 - If TYPE == ANTI_RANGE the variable is known to NOT
68 take any values in the range [MIN, MAX]. */
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. */
77 typedef struct value_range_d value_range_t;
79 /* Set of SSA names found live during the RPO traversal of the function
80 for still active basic-blocks. */
83 /* Return true if the SSA name NAME is live on the edge E. */
86 live_on_edge (edge e, tree name)
88 return (live[e->dest->index]
89 && TEST_BIT (live[e->dest->index], SSA_NAME_VERSION (name)));
92 /* Local functions. */
93 static int compare_values (tree val1, tree val2);
94 static int compare_values_warnv (tree val1, tree val2, bool *);
95 static void vrp_meet (value_range_t *, value_range_t *);
96 static tree vrp_evaluate_conditional_warnv_with_ops (enum tree_code,
97 tree, tree, bool, bool *,
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
105 struct assert_locus_d
107 /* Basic block where the assertion would be inserted. */
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. */
114 /* Pointer to the statement that generated this assertion. */
115 gimple_stmt_iterator si;
117 /* Predicate code for the ASSERT_EXPR. Must be COMPARISON_CLASS_P. */
118 enum tree_code comp_code;
120 /* Value being compared against. */
123 /* Expression to compare. */
126 /* Next node in the linked list. */
127 struct assert_locus_d *next;
130 typedef struct assert_locus_d *assert_locus_t;
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. */
134 static bitmap need_assert_for;
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. */
139 static assert_locus_t *asserts_for;
141 /* Value range array. After propagation, VR_VALUE[I] holds the range
142 of values that SSA name N_I may take. */
143 static unsigned num_vr_values;
144 static value_range_t **vr_value;
145 static bool values_propagated;
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
150 static int *vr_phi_edge_counts;
157 static VEC (edge, heap) *to_remove_edges;
158 DEF_VEC_O(switch_update);
159 DEF_VEC_ALLOC_O(switch_update, heap);
160 static VEC (switch_update, heap) *to_update_switch_stmts;
163 /* Return the maximum value for TYPE. */
166 vrp_val_max (const_tree type)
168 if (!INTEGRAL_TYPE_P (type))
171 return TYPE_MAX_VALUE (type);
174 /* Return the minimum value for TYPE. */
177 vrp_val_min (const_tree type)
179 if (!INTEGRAL_TYPE_P (type))
182 return TYPE_MIN_VALUE (type);
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. */
192 vrp_val_is_max (const_tree val)
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)));
200 /* Return whether VAL is equal to the minimum value of its type. This
201 will be true for a negative overflow infinity. */
204 vrp_val_is_min (const_tree val)
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)));
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. */
220 needs_overflow_infinity (const_tree type)
222 return INTEGRAL_TYPE_P (type) && !TYPE_OVERFLOW_WRAPS (type);
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
232 supports_overflow_infinity (const_tree type)
234 tree min = vrp_val_min (type), max = vrp_val_max (type);
235 #ifdef ENABLE_CHECKING
236 gcc_assert (needs_overflow_infinity (type));
238 return (min != NULL_TREE
239 && CONSTANT_CLASS_P (min)
241 && CONSTANT_CLASS_P (max));
244 /* VAL is the maximum or minimum value of a type. Return a
245 corresponding overflow infinity. */
248 make_overflow_infinity (tree val)
250 gcc_checking_assert (val != NULL_TREE && CONSTANT_CLASS_P (val));
251 val = copy_node (val);
252 TREE_OVERFLOW (val) = 1;
256 /* Return a negative overflow infinity for TYPE. */
259 negative_overflow_infinity (tree type)
261 gcc_checking_assert (supports_overflow_infinity (type));
262 return make_overflow_infinity (vrp_val_min (type));
265 /* Return a positive overflow infinity for TYPE. */
268 positive_overflow_infinity (tree type)
270 gcc_checking_assert (supports_overflow_infinity (type));
271 return make_overflow_infinity (vrp_val_max (type));
274 /* Return whether VAL is a negative overflow infinity. */
277 is_negative_overflow_infinity (const_tree val)
279 return (needs_overflow_infinity (TREE_TYPE (val))
280 && CONSTANT_CLASS_P (val)
281 && TREE_OVERFLOW (val)
282 && vrp_val_is_min (val));
285 /* Return whether VAL is a positive overflow infinity. */
288 is_positive_overflow_infinity (const_tree val)
290 return (needs_overflow_infinity (TREE_TYPE (val))
291 && CONSTANT_CLASS_P (val)
292 && TREE_OVERFLOW (val)
293 && vrp_val_is_max (val));
296 /* Return whether VAL is a positive or negative overflow infinity. */
299 is_overflow_infinity (const_tree val)
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)));
307 /* Return whether STMT has a constant rhs that is_overflow_infinity. */
310 stmt_overflow_infinity (gimple stmt)
312 if (is_gimple_assign (stmt)
313 && get_gimple_rhs_class (gimple_assign_rhs_code (stmt)) ==
315 return is_overflow_infinity (gimple_assign_rhs1 (stmt));
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. */
324 avoid_overflow_infinity (tree val)
326 if (!is_overflow_infinity (val))
329 if (vrp_val_is_max (val))
330 return vrp_val_max (TREE_TYPE (val));
333 gcc_checking_assert (vrp_val_is_min (val));
334 return vrp_val_min (TREE_TYPE (val));
339 /* Return true if ARG is marked with the nonnull attribute in the
340 current function signature. */
343 nonnull_arg_p (const_tree arg)
345 tree t, attrs, fntype;
346 unsigned HOST_WIDE_INT arg_num;
348 gcc_assert (TREE_CODE (arg) == PARM_DECL && POINTER_TYPE_P (TREE_TYPE (arg)));
350 /* The static chain decl is always non null. */
351 if (arg == cfun->static_chain_decl)
354 fntype = TREE_TYPE (current_function_decl);
355 attrs = lookup_attribute ("nonnull", TYPE_ATTRIBUTES (fntype));
357 /* If "nonnull" wasn't specified, we know nothing about the argument. */
358 if (attrs == NULL_TREE)
361 /* If "nonnull" applies to all the arguments, then ARG is non-null. */
362 if (TREE_VALUE (attrs) == NULL_TREE)
365 /* Get the position number for ARG in the function signature. */
366 for (arg_num = 1, t = DECL_ARGUMENTS (current_function_decl);
368 t = DECL_CHAIN (t), arg_num++)
374 gcc_assert (t == arg);
376 /* Now see if ARG_NUM is mentioned in the nonnull list. */
377 for (t = TREE_VALUE (attrs); t; t = TREE_CHAIN (t))
379 if (compare_tree_int (TREE_VALUE (t), arg_num) == 0)
387 /* Set value range VR to VR_VARYING. */
390 set_value_range_to_varying (value_range_t *vr)
392 vr->type = VR_VARYING;
393 vr->min = vr->max = NULL_TREE;
395 bitmap_clear (vr->equiv);
399 /* Set value range VR to {T, MIN, MAX, EQUIV}. */
402 set_value_range (value_range_t *vr, enum value_range_type t, tree min,
403 tree max, bitmap equiv)
405 #if defined ENABLE_CHECKING
406 /* Check the validity of the range. */
407 if (t == VR_RANGE || t == VR_ANTI_RANGE)
411 gcc_assert (min && max);
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));
416 cmp = compare_values (min, max);
417 gcc_assert (cmp == 0 || cmp == -1 || cmp == -2);
419 if (needs_overflow_infinity (TREE_TYPE (min)))
420 gcc_assert (!is_overflow_infinity (min)
421 || !is_overflow_infinity (max));
424 if (t == VR_UNDEFINED || t == VR_VARYING)
425 gcc_assert (min == NULL_TREE && max == NULL_TREE);
427 if (t == VR_UNDEFINED || t == VR_VARYING)
428 gcc_assert (equiv == NULL || bitmap_empty_p (equiv));
435 /* Since updating the equivalence set involves deep copying the
436 bitmaps, only do it if absolutely necessary. */
437 if (vr->equiv == NULL
439 vr->equiv = BITMAP_ALLOC (NULL);
441 if (equiv != vr->equiv)
443 if (equiv && !bitmap_empty_p (equiv))
444 bitmap_copy (vr->equiv, equiv);
446 bitmap_clear (vr->equiv);
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
457 This routine exists to ease canonicalization in the case where we
458 extract ranges from var + CST op limit. */
461 set_and_canonicalize_value_range (value_range_t *vr, enum value_range_type t,
462 tree min, tree max, bitmap equiv)
464 /* Nothing to canonicalize for symbolic or unknown or varying ranges. */
466 && t != VR_ANTI_RANGE)
467 || TREE_CODE (min) != INTEGER_CST
468 || TREE_CODE (max) != INTEGER_CST)
470 set_value_range (vr, t, min, max, equiv);
474 /* Wrong order for min and max, to swap them and the VR type we need
476 if (tree_int_cst_lt (max, min))
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);
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))
488 set_value_range_to_varying (vr);
492 t = t == VR_RANGE ? VR_ANTI_RANGE : VR_RANGE;
495 /* Anti-ranges that can be represented as ranges should be so. */
496 if (t == VR_ANTI_RANGE)
498 bool is_min = vrp_val_is_min (min);
499 bool is_max = vrp_val_is_max (max);
501 if (is_min && is_max)
503 /* We cannot deal with empty ranges, drop to varying. */
504 set_value_range_to_varying (vr);
508 /* As a special exception preserve non-null ranges. */
509 && !(TYPE_UNSIGNED (TREE_TYPE (min))
510 && integer_zerop (max)))
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));
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));
526 set_value_range (vr, t, min, max, equiv);
529 /* Copy value range FROM into value range TO. */
532 copy_value_range (value_range_t *to, value_range_t *from)
534 set_value_range (to, from->type, from->min, from->max, from->equiv);
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. */
543 set_value_range_to_value (value_range_t *vr, tree val, bitmap equiv)
545 gcc_assert (is_gimple_min_invariant (val));
546 val = avoid_overflow_infinity (val);
547 set_value_range (vr, VR_RANGE, val, val, equiv);
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. */
557 set_value_range_to_nonnegative (value_range_t *vr, tree type,
558 bool overflow_infinity)
562 if (overflow_infinity && !supports_overflow_infinity (type))
564 set_value_range_to_varying (vr);
568 zero = build_int_cst (type, 0);
569 set_value_range (vr, VR_RANGE, zero,
571 ? positive_overflow_infinity (type)
572 : TYPE_MAX_VALUE (type)),
576 /* Set value range VR to a non-NULL range of type TYPE. */
579 set_value_range_to_nonnull (value_range_t *vr, tree type)
581 tree zero = build_int_cst (type, 0);
582 set_value_range (vr, VR_ANTI_RANGE, zero, zero, vr->equiv);
586 /* Set value range VR to a NULL range of type TYPE. */
589 set_value_range_to_null (value_range_t *vr, tree type)
591 set_value_range_to_value (vr, build_int_cst (type, 0), vr->equiv);
595 /* Set value range VR to a range of a truthvalue of type TYPE. */
598 set_value_range_to_truthvalue (value_range_t *vr, tree type)
600 if (TYPE_PRECISION (type) == 1)
601 set_value_range_to_varying (vr);
603 set_value_range (vr, VR_RANGE,
604 build_int_cst (type, 0), build_int_cst (type, 1),
609 /* Set value range VR to VR_UNDEFINED. */
612 set_value_range_to_undefined (value_range_t *vr)
614 vr->type = VR_UNDEFINED;
615 vr->min = vr->max = NULL_TREE;
617 bitmap_clear (vr->equiv);
621 /* If abs (min) < abs (max), set VR to [-max, max], if
622 abs (min) >= abs (max), set VR to [-min, min]. */
625 abs_extent_range (value_range_t *vr, tree min, tree max)
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))
637 set_value_range_to_varying (vr);
640 cmp = compare_values (min, max);
642 min = fold_unary (NEGATE_EXPR, TREE_TYPE (min), max);
643 else if (cmp == 0 || cmp == 1)
646 min = fold_unary (NEGATE_EXPR, TREE_TYPE (min), min);
650 set_value_range_to_varying (vr);
653 set_and_canonicalize_value_range (vr, VR_RANGE, min, max, NULL);
657 /* Return value range information for VAR.
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. */
662 static value_range_t *
663 get_value_range (const_tree var)
665 static const struct value_range_d vr_const_varying
666 = { VR_VARYING, NULL_TREE, NULL_TREE, NULL };
669 unsigned ver = SSA_NAME_VERSION (var);
671 /* If we have no recorded ranges, then return NULL. */
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);
685 /* After propagation finished do not allocate new value-ranges. */
686 if (values_propagated)
687 return CONST_CAST (value_range_t *, &vr_const_varying);
689 /* Create a default value range. */
690 vr_value[ver] = vr = XCNEW (value_range_t);
692 /* Defer allocating the equivalence set. */
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))
700 if (TREE_CODE (sym) == PARM_DECL)
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));
709 set_value_range_to_varying (vr);
711 else if (TREE_CODE (sym) == RESULT_DECL
712 && DECL_BY_REFERENCE (sym))
713 set_value_range_to_nonnull (vr, TREE_TYPE (sym));
719 /* Return true, if VAL1 and VAL2 are equal values for VRP purposes. */
722 vrp_operand_equal_p (const_tree val1, const_tree val2)
726 if (!val1 || !val2 || !operand_equal_p (val1, val2, 0))
728 if (is_overflow_infinity (val1))
729 return is_overflow_infinity (val2);
733 /* Return true, if the bitmaps B1 and B2 are equal. */
736 vrp_bitmap_equal_p (const_bitmap b1, const_bitmap b2)
739 || ((!b1 || bitmap_empty_p (b1))
740 && (!b2 || bitmap_empty_p (b2)))
742 && bitmap_equal_p (b1, b2)));
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
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. */
756 update_value_range (const_tree var, value_range_t *new_vr)
758 value_range_t *old_vr;
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);
769 set_value_range (old_vr, new_vr->type, new_vr->min, new_vr->max,
772 BITMAP_FREE (new_vr->equiv);
778 /* Add VAR and VAR's equivalence set to EQUIV. This is the central
779 point where equivalence processing can be turned on/off. */
782 add_equivalence (bitmap *equiv, const_tree var)
784 unsigned ver = SSA_NAME_VERSION (var);
785 value_range_t *vr = vr_value[ver];
788 *equiv = BITMAP_ALLOC (NULL);
789 bitmap_set_bit (*equiv, ver);
791 bitmap_ior_into (*equiv, vr->equiv);
795 /* Return true if VR is ~[0, 0]. */
798 range_is_nonnull (value_range_t *vr)
800 return vr->type == VR_ANTI_RANGE
801 && integer_zerop (vr->min)
802 && integer_zerop (vr->max);
806 /* Return true if VR is [0, 0]. */
809 range_is_null (value_range_t *vr)
811 return vr->type == VR_RANGE
812 && integer_zerop (vr->min)
813 && integer_zerop (vr->max);
816 /* Return true if max and min of VR are INTEGER_CST. It's not necessary
820 range_int_cst_p (value_range_t *vr)
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));
829 /* Return true if VR is a INTEGER_CST singleton. */
832 range_int_cst_singleton_p (value_range_t *vr)
834 return (range_int_cst_p (vr)
835 && tree_int_cst_equal (vr->min, vr->max));
838 /* Return true if value range VR involves at least one symbol. */
841 symbolic_range_p (value_range_t *vr)
843 return (!is_gimple_min_invariant (vr->min)
844 || !is_gimple_min_invariant (vr->max));
847 /* Return true if value range VR uses an overflow infinity. */
850 overflow_infinity_range_p (value_range_t *vr)
852 return (vr->type == VR_RANGE
853 && (is_overflow_infinity (vr->min)
854 || is_overflow_infinity (vr->max)));
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. */
864 usable_range_p (value_range_t *vr, bool *strict_overflow_p)
866 gcc_assert (vr->type == VR_RANGE);
867 if (is_overflow_infinity (vr->min))
869 *strict_overflow_p = true;
870 if (!TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (vr->min)))
873 if (is_overflow_infinity (vr->max))
875 *strict_overflow_p = true;
876 if (!TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (vr->max)))
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.*/
889 gimple_assign_nonnegative_warnv_p (gimple stmt, bool *strict_overflow_p)
891 enum tree_code code = gimple_assign_rhs_code (stmt);
892 switch (get_gimple_rhs_class (code))
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),
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),
905 case GIMPLE_TERNARY_RHS:
907 case GIMPLE_SINGLE_RHS:
908 return tree_single_nonnegative_warnv_p (gimple_assign_rhs1 (stmt),
910 case GIMPLE_INVALID_RHS:
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.*/
923 gimple_call_nonnegative_warnv_p (gimple stmt, bool *strict_overflow_p)
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;
930 return tree_call_nonnegative_warnv_p (gimple_expr_type (stmt),
931 gimple_call_fndecl (stmt),
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.*/
943 gimple_stmt_nonnegative_warnv_p (gimple stmt, bool *strict_overflow_p)
945 switch (gimple_code (stmt))
948 return gimple_assign_nonnegative_warnv_p (stmt, strict_overflow_p);
950 return gimple_call_nonnegative_warnv_p (stmt, strict_overflow_p);
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.*/
962 gimple_assign_nonzero_warnv_p (gimple stmt, bool *strict_overflow_p)
964 enum tree_code code = gimple_assign_rhs_code (stmt);
965 switch (get_gimple_rhs_class (code))
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),
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),
978 case GIMPLE_TERNARY_RHS:
980 case GIMPLE_SINGLE_RHS:
981 return tree_single_nonzero_warnv_p (gimple_assign_rhs1 (stmt),
983 case GIMPLE_INVALID_RHS:
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.*/
996 gimple_stmt_nonzero_warnv_p (gimple stmt, bool *strict_overflow_p)
998 switch (gimple_code (stmt))
1001 return gimple_assign_nonzero_warnv_p (stmt, strict_overflow_p);
1003 return gimple_alloca_call_p (stmt);
1009 /* Like tree_expr_nonzero_warnv_p, but this function uses value ranges
1013 vrp_stmt_computes_nonzero (gimple stmt, bool *strict_overflow_p)
1015 if (gimple_stmt_nonzero_warnv_p (stmt, strict_overflow_p))
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)
1023 tree expr = gimple_assign_rhs1 (stmt);
1024 tree base = get_base_address (TREE_OPERAND (expr, 0));
1026 if (base != NULL_TREE
1027 && TREE_CODE (base) == MEM_REF
1028 && TREE_CODE (TREE_OPERAND (base, 0)) == SSA_NAME)
1030 value_range_t *vr = get_value_range (TREE_OPERAND (base, 0));
1031 if (range_is_nonnull (vr))
1039 /* Returns true if EXPR is a valid value (as expected by compare_values) --
1040 a gimple invariant, or SSA_NAME +- CST. */
1043 valid_value_p (tree expr)
1045 if (TREE_CODE (expr) == SSA_NAME)
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);
1053 return is_gimple_min_invariant (expr);
1059 -2 if those are incomparable. */
1061 operand_less_p (tree val, tree val2)
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)
1066 if (TYPE_UNSIGNED (TREE_TYPE (val)))
1067 return INT_CST_LT_UNSIGNED (val, val2);
1070 if (INT_CST_LT (val, val2))
1078 fold_defer_overflow_warnings ();
1080 tcmp = fold_binary_to_constant (LT_EXPR, boolean_type_node, val, val2);
1082 fold_undefer_and_ignore_overflow_warnings ();
1085 || TREE_CODE (tcmp) != INTEGER_CST)
1088 if (!integer_zerop (tcmp))
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;
1101 /* Compare two values VAL1 and VAL2. Return
1103 -2 if VAL1 and VAL2 cannot be compared at compile-time,
1106 +1 if VAL1 > VAL2, and
1109 This is similar to tree_int_cst_compare but supports pointer values
1110 and values that cannot be compared at compile time.
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. */
1117 compare_values_warnv (tree val1, tree val2, bool *strict_overflow_p)
1122 /* Below we rely on the fact that VAL1 and VAL2 are both pointers or
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);
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))
1138 tree n1, c1, n2, c2;
1139 enum tree_code code1, code2;
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)
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)
1157 if (is_negative_overflow_infinity (c1))
1159 c1 = fold_unary_to_constant (NEGATE_EXPR, TREE_TYPE (c1), c1);
1162 code1 = code1 == MINUS_EXPR ? PLUS_EXPR : MINUS_EXPR;
1166 if (TREE_CODE (val2) == SSA_NAME)
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)
1179 if (is_negative_overflow_infinity (c2))
1181 c2 = fold_unary_to_constant (NEGATE_EXPR, TREE_TYPE (c2), c2);
1184 code2 = code2 == MINUS_EXPR ? PLUS_EXPR : MINUS_EXPR;
1188 /* Both values must use the same name. */
1192 if (code1 == SSA_NAME
1193 && code2 == SSA_NAME)
1197 /* If overflow is defined we cannot simplify more. */
1198 if (!TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (val1)))
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;
1206 if (code1 == SSA_NAME)
1208 if (code2 == PLUS_EXPR)
1209 /* NAME < NAME + CST */
1211 else if (code2 == MINUS_EXPR)
1212 /* NAME > NAME - CST */
1215 else if (code1 == PLUS_EXPR)
1217 if (code2 == SSA_NAME)
1218 /* NAME + CST > NAME */
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 */
1227 else if (code1 == MINUS_EXPR)
1229 if (code2 == SSA_NAME)
1230 /* NAME - CST < NAME */
1232 else if (code2 == PLUS_EXPR)
1233 /* NAME - CST1 < NAME + CST2 */
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);
1244 /* We cannot compare non-constants. */
1245 if (!is_gimple_min_invariant (val1) || !is_gimple_min_invariant (val2))
1248 if (!POINTER_TYPE_P (TREE_TYPE (val1)))
1250 /* We cannot compare overflowed values, except for overflow
1252 if (TREE_OVERFLOW (val1) || TREE_OVERFLOW (val2))
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))
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))
1267 return tree_int_cst_compare (val1, val2);
1273 /* First see if VAL1 and VAL2 are not the same. */
1274 if (val1 == val2 || operand_equal_p (val1, val2, 0))
1277 /* If VAL1 is a lower address than VAL2, return -1. */
1278 if (operand_less_p (val1, val2) == 1)
1281 /* If VAL1 is a higher address than VAL2, return +1. */
1282 if (operand_less_p (val2, val1) == 1)
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)
1292 t = fold_binary_to_constant (NE_EXPR, boolean_type_node, val1, val2);
1293 if (t && integer_onep (t))
1301 /* Compare values like compare_values_warnv, but treat comparisons of
1302 nonconstants which rely on undefined overflow as incomparable. */
1305 compare_values (tree val1, tree val2)
1311 ret = compare_values_warnv (val1, val2, &sop);
1313 && (!is_gimple_min_invariant (val1) || !is_gimple_min_invariant (val2)))
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.
1323 Benchmark compile/20001226-1.c compilation time after changing this
1327 value_inside_range (tree val, tree min, tree max)
1331 cmp1 = operand_less_p (val, min);
1337 cmp2 = operand_less_p (max, val);
1345 /* Return true if value ranges VR0 and VR1 have a non-empty
1348 Benchmark compile/20001226-1.c compilation time after changing this
1353 value_ranges_intersect_p (value_range_t *vr0, value_range_t *vr1)
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)
1360 if (operand_less_p (vr1->max, vr0->min) != 0)
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. */
1370 range_includes_zero_p (tree min, tree max)
1372 tree zero = build_int_cst (TREE_TYPE (min), 0);
1373 return value_inside_range (zero, min, max);
1376 /* Return true if *VR is know to only contain nonnegative values. */
1379 value_range_nonnegative_p (value_range_t *vr)
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
1384 if (vr->type == VR_RANGE)
1386 int result = compare_values (vr->min, integer_zero_node);
1387 return (result == 0 || result == 1);
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. */
1397 ssa_name_nonnegative_p (const_tree t)
1399 value_range_t *vr = get_value_range (t);
1401 if (INTEGRAL_TYPE_P (t)
1402 && TYPE_UNSIGNED (t))
1408 return value_range_nonnegative_p (vr);
1411 /* If *VR has a value rante that is a single constant value return that,
1412 otherwise return NULL_TREE. */
1415 value_range_constant_singleton (value_range_t *vr)
1417 if (vr->type == VR_RANGE
1418 && operand_equal_p (vr->min, vr->max, 0)
1419 && is_gimple_min_invariant (vr->min))
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
1430 op_with_constant_singleton_value_range (tree op)
1432 if (is_gimple_min_invariant (op))
1435 if (TREE_CODE (op) != SSA_NAME)
1438 return value_range_constant_singleton (get_value_range (op));
1441 /* Return true if op is in a boolean [0, 1] value-range. */
1444 op_with_boolean_value_range_p (tree op)
1448 if (TYPE_PRECISION (TREE_TYPE (op)) == 1)
1451 if (integer_zerop (op)
1452 || integer_onep (op))
1455 if (TREE_CODE (op) != SSA_NAME)
1458 vr = get_value_range (op);
1459 return (vr->type == VR_RANGE
1460 && integer_zerop (vr->min)
1461 && integer_onep (vr->max));
1464 /* Extract value range information from an ASSERT_EXPR EXPR and store
1468 extract_range_from_assert (value_range_t *vr_p, tree expr)
1470 tree var, cond, limit, min, max, type;
1471 value_range_t *var_vr, *limit_vr;
1472 enum tree_code cond_code;
1474 var = ASSERT_EXPR_VAR (expr);
1475 cond = ASSERT_EXPR_COND (expr);
1477 gcc_assert (COMPARISON_CLASS_P (cond));
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)
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);
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
1495 cond_code = swap_tree_comparison (TREE_CODE (cond));
1496 limit = TREE_OPERAND (cond, 0);
1497 cond = TREE_OPERAND (cond, 1);
1500 limit = avoid_overflow_infinity (limit);
1502 type = TREE_TYPE (var);
1503 gcc_assert (limit != var);
1505 /* For pointer arithmetic, we only keep track of pointer equality
1507 if (POINTER_TYPE_P (type) && cond_code != NE_EXPR && cond_code != EQ_EXPR)
1509 set_value_range_to_varying (vr_p);
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
1516 limit_vr = (TREE_CODE (limit) == SSA_NAME) ? get_value_range (limit) : NULL;
1518 /* LIMIT's range is only interesting if it has any useful information. */
1520 && (limit_vr->type == VR_UNDEFINED
1521 || limit_vr->type == VR_VARYING
1522 || symbolic_range_p (limit_vr)))
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
1530 gcc_assert (vr_p->equiv == NULL);
1531 add_equivalence (&vr_p->equiv, var);
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)
1547 if (TREE_CODE (cond) == PLUS_EXPR)
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);
1556 min = build_int_cst (TREE_TYPE (var), 0);
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),
1565 max = force_fit_type_double (TREE_TYPE (var), tree_to_double_int (max),
1568 /* We can transform a max, min range to an anti-range or
1569 vice-versa. Use set_and_canonicalize_value_range which does
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);
1580 else if (cond_code == EQ_EXPR)
1582 enum value_range_type range_type;
1586 range_type = limit_vr->type;
1587 min = limit_vr->min;
1588 max = limit_vr->max;
1592 range_type = VR_RANGE;
1597 set_value_range (vr_p, range_type, min, max, vr_p->equiv);
1599 /* When asserting the equality VAR == LIMIT and LIMIT is another
1600 SSA name, the new range will also inherit the equivalence set
1602 if (TREE_CODE (limit) == SSA_NAME)
1603 add_equivalence (&vr_p->equiv, limit);
1605 else if (cond_code == NE_EXPR)
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
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.
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]. */
1628 && limit_vr->type == VR_RANGE
1629 && compare_values (limit_vr->min, limit_vr->max) == 0)
1631 min = limit_vr->min;
1632 max = limit_vr->max;
1636 /* In any other case, we cannot use LIMIT's range to build a
1637 valid anti-range. */
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))
1648 set_value_range (vr_p, VR_ANTI_RANGE, min, max, vr_p->equiv);
1650 else if (cond_code == LE_EXPR || cond_code == LT_EXPR)
1652 min = TYPE_MIN_VALUE (type);
1654 if (limit_vr == NULL || limit_vr->type == VR_ANTI_RANGE)
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
1661 max = limit_vr->max;
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);
1673 /* For LT_EXPR, we create the range [MIN, MAX - 1]. */
1674 if (cond_code == LT_EXPR)
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));
1681 max = fold_build2 (MINUS_EXPR, TREE_TYPE (max), max,
1682 build_int_cst (TREE_TYPE (max), 1));
1684 TREE_NO_WARNING (max) = 1;
1687 set_value_range (vr_p, VR_RANGE, min, max, vr_p->equiv);
1690 else if (cond_code == GE_EXPR || cond_code == GT_EXPR)
1692 max = TYPE_MAX_VALUE (type);
1694 if (limit_vr == NULL || limit_vr->type == VR_ANTI_RANGE)
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
1701 min = limit_vr->min;
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);
1713 /* For GT_EXPR, we create the range [MIN + 1, MAX]. */
1714 if (cond_code == GT_EXPR)
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));
1721 min = fold_build2 (PLUS_EXPR, TREE_TYPE (min), min,
1722 build_int_cst (TREE_TYPE (min), 1));
1724 TREE_NO_WARNING (min) = 1;
1727 set_value_range (vr_p, VR_RANGE, min, max, vr_p->equiv);
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
1738 p_6 = ASSERT_EXPR <p_5, p_5 == NULL>;
1740 p_8 = ASSERT_EXPR <p_6, p_6 != NULL>;
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
1748 i_6 = ASSERT_EXPR <i_5, i_5 > 10>;
1750 i_7 = ASSERT_EXPR <i_6, i_6 < 5>;
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.
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. */
1767 var_vr = get_value_range (var);
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))
1779 if (var_vr->type == VR_RANGE && vr_p->type == VR_RANGE)
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))
1788 /* Use the larger of the two minimums. */
1789 if (compare_values (vr_p->min, var_vr->min) == -1)
1794 /* Use the smaller of the two maximums. */
1795 if (compare_values (vr_p->max, var_vr->max) == 1)
1800 set_value_range (vr_p, vr_p->type, min, max, vr_p->equiv);
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);
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))
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);
1822 tree min, max, anti_min, anti_max, real_min, real_max;
1825 /* We want to compute the logical AND of the two ranges;
1826 there are three cases to consider.
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.
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.
1839 3. There is some overlap between the VR_ANTI_RANGE
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.
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)
1855 anti_min = vr_p->min;
1856 anti_max = vr_p->max;
1857 real_min = var_vr->min;
1858 real_max = var_vr->max;
1862 anti_min = var_vr->min;
1863 anti_max = var_vr->max;
1864 real_min = vr_p->min;
1865 real_max = vr_p->max;
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)
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);
1881 /* Case 2, VR_ANTI_RANGE completely disjoint from
1883 else if (compare_values (anti_min, real_max) == 1
1884 || compare_values (anti_max, real_min) == -1)
1886 set_value_range (vr_p, VR_RANGE, real_min,
1887 real_max, vr_p->equiv);
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
1894 && compare_values (anti_max, real_max) == -1)
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))
1900 if (!supports_overflow_infinity (TREE_TYPE (var_vr->min)))
1902 set_value_range_to_varying (vr_p);
1905 min = positive_overflow_infinity (TREE_TYPE (var_vr->min));
1907 else if (!POINTER_TYPE_P (TREE_TYPE (var_vr->min)))
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),
1913 build_int_cst (TREE_TYPE (var_vr->min),
1916 min = fold_build2 (PLUS_EXPR, TREE_TYPE (var_vr->min),
1918 build_int_cst (TREE_TYPE (var_vr->min),
1922 min = fold_build_pointer_plus_hwi (anti_max, 1);
1924 set_value_range (vr_p, VR_RANGE, min, max, vr_p->equiv);
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
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))
1937 if (!supports_overflow_infinity (TREE_TYPE (var_vr->min)))
1939 set_value_range_to_varying (vr_p);
1942 max = negative_overflow_infinity (TREE_TYPE (var_vr->min));
1944 else if (!POINTER_TYPE_P (TREE_TYPE (var_vr->min)))
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),
1950 build_int_cst (TREE_TYPE (var_vr->min),
1953 max = fold_build2 (MINUS_EXPR, TREE_TYPE (var_vr->min),
1955 build_int_cst (TREE_TYPE (var_vr->min),
1959 max = fold_build_pointer_plus_hwi (anti_min, -1);
1961 set_value_range (vr_p, VR_RANGE, min, max, vr_p->equiv);
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
1978 Even if y_5 is deemed VARYING, we can determine that x_3 > y_5 is
1982 extract_range_from_ssa_name (value_range_t *vr, tree var)
1984 value_range_t *var_vr = get_value_range (var);
1986 if (var_vr->type != VR_UNDEFINED && var_vr->type != VR_VARYING)
1987 copy_value_range (vr, var_vr);
1989 set_value_range (vr, VR_RANGE, var, var, NULL);
1991 add_equivalence (&vr->equiv, var);
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. */
2002 vrp_int_const_binop (enum tree_code code, tree val1, tree val2)
2006 res = int_const_binop (code, val1, val2);
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)))
2012 int checkz = compare_values (res, val1);
2013 bool overflow = false;
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)))
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))
2031 tree tmp = int_const_binop (TRUNC_DIV_EXPR,
2034 int check = compare_values (tmp, val2);
2042 res = copy_node (res);
2043 TREE_OVERFLOW (res) = 1;
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. */
2051 else if ((TREE_OVERFLOW (res)
2052 && !TREE_OVERFLOW (val1)
2053 && !TREE_OVERFLOW (val2))
2054 || is_overflow_infinity (val1)
2055 || is_overflow_infinity (val2))
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);
2063 if (needs_overflow_infinity (TREE_TYPE (res))
2064 && !supports_overflow_infinity (TREE_TYPE (res)))
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))
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)))
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. */
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
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
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
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)));
2133 return (needs_overflow_infinity (TREE_TYPE (res))
2134 ? negative_overflow_infinity (TREE_TYPE (res))
2135 : TYPE_MIN_VALUE (TREE_TYPE (res)));
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. */
2149 zero_nonzero_bits_from_vr (value_range_t *vr,
2150 double_int *may_be_nonzero,
2151 double_int *must_be_nonzero)
2153 *may_be_nonzero = double_int_minus_one;
2154 *must_be_nonzero = double_int_zero;
2155 if (!range_int_cst_p (vr))
2158 if (range_int_cst_singleton_p (vr))
2160 *may_be_nonzero = tree_to_double_int (vr->min);
2161 *must_be_nonzero = *may_be_nonzero;
2163 else if (tree_int_cst_sgn (vr->min) >= 0
2164 || tree_int_cst_sgn (vr->max) < 0)
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)
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;
2181 else if (xor_mask.low != 0)
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;
2194 /* Helper to extract a value-range *VR for a multiplicative operation
2198 extract_range_from_multiplicative_op_1 (value_range_t *vr,
2199 enum tree_code code,
2200 value_range_t *vr0, value_range_t *vr1)
2202 enum value_range_type type;
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
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
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);
2234 /* Compute the 4 cross operations. */
2236 val[0] = vrp_int_const_binop (code, vr0->min, vr1->min);
2237 if (val[0] == NULL_TREE)
2240 if (vr1->max == vr1->min)
2244 val[1] = vrp_int_const_binop (code, vr0->min, vr1->max);
2245 if (val[1] == NULL_TREE)
2249 if (vr0->max == vr0->min)
2253 val[2] = vrp_int_const_binop (code, vr0->max, vr1->min);
2254 if (val[2] == NULL_TREE)
2258 if (vr0->min == vr0->max || vr1->min == vr1->max)
2262 val[3] = vrp_int_const_binop (code, vr0->max, vr1->max);
2263 if (val[3] == NULL_TREE)
2269 set_value_range_to_varying (vr);
2273 /* Set MIN to the minimum of VAL[i] and MAX to the maximum
2277 for (i = 1; i < 4; i++)
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)))
2287 if (!is_gimple_min_invariant (val[i])
2288 || (TREE_OVERFLOW (val[i])
2289 && !is_overflow_infinity (val[i])))
2291 /* If we found an overflowed value, set MIN and MAX
2292 to it so that we set the resulting range to
2298 if (compare_values (val[i], min) == -1)
2301 if (compare_values (val[i], max) == 1)
2306 /* If either MIN or MAX overflowed, then set the resulting range to
2307 VARYING. But we do accept an overflow infinity
2309 if (min == NULL_TREE
2310 || !is_gimple_min_invariant (min)
2311 || (TREE_OVERFLOW (min) && !is_overflow_infinity (min))
2313 || !is_gimple_min_invariant (max)
2314 || (TREE_OVERFLOW (max) && !is_overflow_infinity (max)))
2316 set_value_range_to_varying (vr);
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
2328 if ((vrp_val_is_min (min) || is_overflow_infinity (min))
2329 && (vrp_val_is_max (max) || is_overflow_infinity (max)))
2331 set_value_range_to_varying (vr);
2335 cmp = compare_values (min, max);
2336 if (cmp == -2 || cmp == 1)
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);
2344 set_value_range (vr, type, min, max, NULL);
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. */
2352 extract_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_)
2356 value_range_t vr0 = *vr0_, vr1 = *vr1_;
2357 enum value_range_type type;
2358 tree min = NULL_TREE, max = NULL_TREE;
2361 if (!INTEGRAL_TYPE_P (expr_type)
2362 && !POINTER_TYPE_P (expr_type))
2364 set_value_range_to_varying (vr);
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
2383 && code != BIT_AND_EXPR
2384 && code != BIT_IOR_EXPR
2385 && code != BIT_XOR_EXPR)
2387 set_value_range_to_varying (vr);
2391 /* If both ranges are UNDEFINED, so is the result. */
2392 if (vr0.type == VR_UNDEFINED && vr1.type == VR_UNDEFINED)
2394 set_value_range_to_undefined (vr);
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
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);
2406 /* The type of the resulting value range defaults to VR0.TYPE. */
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
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)))
2429 set_value_range_to_varying (vr);
2433 /* Now evaluate the expression to determine the new range. */
2434 if (POINTER_TYPE_P (expr_type))
2436 if (code == MIN_EXPR || code == MAX_EXPR)
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
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);
2447 set_value_range_to_varying (vr);
2449 else if (code == POINTER_PLUS_EXPR)
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);
2458 set_value_range_to_varying (vr);
2460 else if (code == BIT_AND_EXPR)
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);
2469 set_value_range_to_varying (vr);
2472 set_value_range_to_varying (vr);
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)
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
2488 if (vr0.type == VR_ANTI_RANGE)
2490 set_value_range_to_varying (vr);
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);
2500 /* If both additions overflowed the range kind is still correct.
2501 This happens regularly with subtracting something in unsigned
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)))
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));
2515 else if (code == MIN_EXPR
2516 || code == MAX_EXPR)
2518 if (vr0.type == VR_ANTI_RANGE)
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);
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);
2535 else if (code == MULT_EXPR)
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
2545 if (vr0.type == VR_ANTI_RANGE
2546 && !TYPE_OVERFLOW_UNDEFINED (expr_type))
2548 set_value_range_to_varying (vr);
2552 extract_range_from_multiplicative_op_1 (vr, code, &vr0, &vr1);
2555 else if (code == RSHIFT_EXPR)
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)
2567 set_value_range_to_varying (vr);
2571 extract_range_from_multiplicative_op_1 (vr, code, &vr0, &vr1);
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)
2580 if (vr0.type != VR_RANGE || symbolic_range_p (&vr0))
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)
2589 vr0.type = type = VR_RANGE;
2590 vr0.min = vrp_val_min (expr_type);
2591 vr0.max = vrp_val_max (expr_type);
2595 set_value_range_to_varying (vr);
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))
2606 set_value_range_to_varying (vr);
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
2613 if (vr0.type == VR_RANGE
2614 && (vr1.type != VR_RANGE
2615 || range_includes_zero_p (vr1.min, vr1.max) != 0))
2617 tree zero = build_int_cst (TREE_TYPE (vr0.min), 0);
2622 if (TYPE_UNSIGNED (expr_type)
2623 || value_range_nonnegative_p (&vr1))
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);
2632 else if (cmp == 0 || cmp == 1)
2636 cmp = compare_values (vr0.min, zero);
2639 else if (cmp == 0 || cmp == -1)
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);
2652 if (type == VR_VARYING)
2654 set_value_range_to_varying (vr);
2660 extract_range_from_multiplicative_op_1 (vr, code, &vr0, &vr1);
2664 else if (code == TRUNC_MOD_EXPR)
2666 if (vr1.type != VR_RANGE
2667 || range_includes_zero_p (vr1.min, vr1.max) != 0
2668 || vrp_val_is_min (vr1.min))
2670 set_value_range_to_varying (vr);
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))
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);
2685 min = fold_unary_to_constant (NEGATE_EXPR, expr_type, max);
2687 else if (code == MINUS_EXPR)
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)
2698 set_value_range_to_varying (vr);
2702 /* For MINUS_EXPR, apply the operation to the opposite ends of
2704 min = vrp_int_const_binop (code, vr0.min, vr1.max);
2705 max = vrp_int_const_binop (code, vr0.max, vr1.min);
2707 else if (code == BIT_AND_EXPR || code == BIT_IOR_EXPR || code == BIT_XOR_EXPR)
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;
2713 int_cst_range0 = zero_nonzero_bits_from_vr (&vr0, &may_be_nonzero0,
2715 int_cst_range1 = zero_nonzero_bits_from_vr (&vr1, &may_be_nonzero1,
2719 if (code == BIT_AND_EXPR)
2722 min = double_int_to_tree (expr_type,
2723 double_int_and (must_be_nonzero0,
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)
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));
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);
2749 else if (code == BIT_IOR_EXPR)
2752 max = double_int_to_tree (expr_type,
2753 double_int_ior (may_be_nonzero0,
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)
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));
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);
2779 else if (code == BIT_XOR_EXPR)
2781 double_int result_zero_bits, result_one_bits;
2783 = double_int_ior (double_int_and (must_be_nonzero0,
2786 (double_int_ior (may_be_nonzero0,
2789 = double_int_ior (double_int_and
2791 double_int_not (may_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)
2804 max = min = NULL_TREE;
2810 /* If either MIN or MAX overflowed, then set the resulting range to
2811 VARYING. But we do accept an overflow infinity
2813 if (min == NULL_TREE
2814 || !is_gimple_min_invariant (min)
2815 || (TREE_OVERFLOW (min) && !is_overflow_infinity (min))
2817 || !is_gimple_min_invariant (max)
2818 || (TREE_OVERFLOW (max) && !is_overflow_infinity (max)))
2820 set_value_range_to_varying (vr);
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
2832 if ((vrp_val_is_min (min) || is_overflow_infinity (min))
2833 && (vrp_val_is_max (max) || is_overflow_infinity (max)))
2835 set_value_range_to_varying (vr);
2839 cmp = compare_values (min, max);
2840 if (cmp == -2 || cmp == 1)
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);
2848 set_value_range (vr, type, min, max, NULL);
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. */
2856 extract_range_from_binary_expr (value_range_t *vr,
2857 enum tree_code code,
2858 tree expr_type, tree op0, tree op1)
2860 value_range_t vr0 = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
2861 value_range_t vr1 = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
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);
2870 set_value_range_to_varying (&vr0);
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);
2877 set_value_range_to_varying (&vr1);
2879 extract_range_from_binary_expr_1 (vr, code, expr_type, &vr0, &vr1);
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. */
2887 extract_range_from_unary_expr_1 (value_range_t *vr,
2888 enum tree_code code, tree type,
2889 value_range_t *vr0_, tree op0_type)
2891 value_range_t vr0 = *vr0_;
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)))
2899 set_value_range_to_varying (vr);
2903 /* If VR0 is UNDEFINED, so is the result. */
2904 if (vr0.type == VR_UNDEFINED)
2906 set_value_range_to_undefined (vr);
2910 if (CONVERT_EXPR_CODE_P (code))
2912 tree inner_type = op0_type;
2913 tree outer_type = type;
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))
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);
2924 set_value_range_to_varying (vr);
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))
2934 vr0.type = VR_RANGE;
2935 vr0.min = TYPE_MIN_VALUE (inner_type);
2936 vr0.max = TYPE_MAX_VALUE (inner_type);
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)))))))
2965 tree new_min, new_max;
2966 if (is_overflow_infinity (vr0.min))
2967 new_min = negative_overflow_infinity (outer_type);
2969 new_min = force_fit_type_double (outer_type,
2970 tree_to_double_int (vr0.min),
2972 if (is_overflow_infinity (vr0.max))
2973 new_max = positive_overflow_infinity (outer_type);
2975 new_max = force_fit_type_double (outer_type,
2976 tree_to_double_int (vr0.max),
2978 set_and_canonicalize_value_range (vr, vr0.type,
2979 new_min, new_max, NULL);
2983 set_value_range_to_varying (vr);
2986 else if (code == NEGATE_EXPR)
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);
2995 else if (code == ABS_EXPR)
3000 /* Pass through vr0 in the easy cases. */
3001 if (TYPE_UNSIGNED (type)
3002 || value_range_nonnegative_p (&vr0))
3004 copy_value_range (vr, &vr0);
3008 /* For the remaining varying or symbolic ranges we can't do anything
3010 if (vr0.type == VR_VARYING
3011 || symbolic_range_p (&vr0))
3013 set_value_range_to_varying (vr);
3017 /* -TYPE_MIN_VALUE = TYPE_MIN_VALUE with flag_wrapv so we can't get a
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))))
3025 set_value_range_to_varying (vr);
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);
3041 set_value_range_to_varying (vr);
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);
3058 set_value_range_to_varying (vr);
3062 cmp = compare_values (min, max);
3064 /* If a VR_ANTI_RANGEs contains zero, then we have
3065 ~[-INF, min(MIN, MAX)]. */
3066 if (vr0.type == VR_ANTI_RANGE)
3068 if (range_includes_zero_p (vr0.min, vr0.max) == 1)
3070 /* Take the lower of the two values. */
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))
3080 tree type_min_value = TYPE_MIN_VALUE (type);
3082 min = (vr0.min != type_min_value
3083 ? int_const_binop (PLUS_EXPR, type_min_value,
3089 if (overflow_infinity_range_p (&vr0))
3090 min = negative_overflow_infinity (type);
3092 min = TYPE_MIN_VALUE (type);
3097 /* All else has failed, so create the range [0, INF], even for
3098 flag_wrapv since TYPE_MIN_VALUE is in the original
3100 vr0.type = VR_RANGE;
3101 min = build_int_cst (type, 0);
3102 if (needs_overflow_infinity (type))
3104 if (supports_overflow_infinity (type))
3105 max = positive_overflow_infinity (type);
3108 set_value_range_to_varying (vr);
3113 max = TYPE_MAX_VALUE (type);
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)
3123 min = build_int_cst (type, 0);
3127 /* If the range was reversed, swap MIN and MAX. */
3136 cmp = compare_values (min, max);
3137 if (cmp == -2 || cmp == 1)
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);
3145 set_value_range (vr, vr0.type, min, max, NULL);
3148 else if (code == BIT_NOT_EXPR)
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);
3158 else if (code == PAREN_EXPR)
3160 copy_value_range (vr, &vr0);
3164 /* For unhandled operations fall back to varying. */
3165 set_value_range_to_varying (vr);
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. */
3175 extract_range_from_unary_expr (value_range_t *vr, enum tree_code code,
3176 tree type, tree op0)
3178 value_range_t vr0 = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
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);
3187 set_value_range_to_varying (&vr0);
3189 extract_range_from_unary_expr_1 (vr, code, type, &vr0, TREE_TYPE (op0));
3193 /* Extract range information from a conditional expression STMT based on
3194 the ranges of each of its operands and the expression code. */
3197 extract_range_from_cond_expr (value_range_t *vr, gimple stmt)
3200 value_range_t vr0 = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
3201 value_range_t vr1 = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
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);
3211 set_value_range_to_varying (&vr0);
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);
3219 set_value_range_to_varying (&vr1);
3221 /* The resulting value range is the union of the operand ranges */
3222 copy_value_range (vr, &vr0);
3223 vrp_meet (vr, &vr1);
3227 /* Extract range information from a comparison expression EXPR based
3228 on the range of its operand and the expression code. */
3231 extract_range_from_comparison (value_range_t *vr, enum tree_code code,
3232 tree type, tree op0, tree op1)
3237 val = vrp_evaluate_conditional_warnv_with_ops (code, op0, op1, false, &sop,
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. */
3245 if (val && !is_overflow_infinity (val) && !sop)
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
3250 val = fold_convert (type, val);
3251 if (is_gimple_min_invariant (val))
3252 set_value_range_to_value (vr, val, vr->equiv);
3254 set_value_range (vr, VR_RANGE, val, val, vr->equiv);
3257 /* The result of a comparison is always true or false. */
3258 set_value_range_to_truthvalue (vr, type);
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 */
3266 extract_range_basic (value_range_t *vr, gimple stmt)
3269 tree type = gimple_expr_type (stmt);
3271 if (INTEGRAL_TYPE_P (type)
3272 && gimple_stmt_nonnegative_warnv_p (stmt, &sop))
3273 set_value_range_to_nonnegative (vr, type,
3274 sop || stmt_overflow_infinity (stmt));
3275 else if (vrp_stmt_computes_nonzero (stmt, &sop)
3277 set_value_range_to_nonnull (vr, type);
3279 set_value_range_to_varying (vr);
3283 /* Try to compute a useful range out of assignment STMT and store it
3287 extract_range_from_assignment (value_range_t *vr, gimple stmt)
3289 enum tree_code code = gimple_assign_rhs_code (stmt);
3291 if (code == ASSERT_EXPR)
3292 extract_range_from_assert (vr, gimple_assign_rhs1 (stmt));
3293 else if (code == SSA_NAME)
3294 extract_range_from_ssa_name (vr, gimple_assign_rhs1 (stmt));
3295 else if (TREE_CODE_CLASS (code) == tcc_binary)
3296 extract_range_from_binary_expr (vr, gimple_assign_rhs_code (stmt),
3297 gimple_expr_type (stmt),
3298 gimple_assign_rhs1 (stmt),
3299 gimple_assign_rhs2 (stmt));
3300 else if (TREE_CODE_CLASS (code) == tcc_unary)
3301 extract_range_from_unary_expr (vr, gimple_assign_rhs_code (stmt),
3302 gimple_expr_type (stmt),
3303 gimple_assign_rhs1 (stmt));
3304 else if (code == COND_EXPR)
3305 extract_range_from_cond_expr (vr, stmt);
3306 else if (TREE_CODE_CLASS (code) == tcc_comparison)
3307 extract_range_from_comparison (vr, gimple_assign_rhs_code (stmt),
3308 gimple_expr_type (stmt),
3309 gimple_assign_rhs1 (stmt),
3310 gimple_assign_rhs2 (stmt));
3311 else if (get_gimple_rhs_class (code) == GIMPLE_SINGLE_RHS
3312 && is_gimple_min_invariant (gimple_assign_rhs1 (stmt)))
3313 set_value_range_to_value (vr, gimple_assign_rhs1 (stmt), NULL);
3315 set_value_range_to_varying (vr);
3317 if (vr->type == VR_VARYING)
3318 extract_range_basic (vr, stmt);
3321 /* Given a range VR, a LOOP and a variable VAR, determine whether it
3322 would be profitable to adjust VR using scalar evolution information
3323 for VAR. If so, update VR with the new limits. */
3326 adjust_range_with_scev (value_range_t *vr, struct loop *loop,
3327 gimple stmt, tree var)
3329 tree init, step, chrec, tmin, tmax, min, max, type, tem;
3330 enum ev_direction dir;
3332 /* TODO. Don't adjust anti-ranges. An anti-range may provide
3333 better opportunities than a regular range, but I'm not sure. */
3334 if (vr->type == VR_ANTI_RANGE)
3337 chrec = instantiate_parameters (loop, analyze_scalar_evolution (loop, var));
3339 /* Like in PR19590, scev can return a constant function. */
3340 if (is_gimple_min_invariant (chrec))
3342 set_value_range_to_value (vr, chrec, vr->equiv);
3346 if (TREE_CODE (chrec) != POLYNOMIAL_CHREC)
3349 init = initial_condition_in_loop_num (chrec, loop->num);
3350 tem = op_with_constant_singleton_value_range (init);
3353 step = evolution_part_in_loop_num (chrec, loop->num);
3354 tem = op_with_constant_singleton_value_range (step);
3358 /* If STEP is symbolic, we can't know whether INIT will be the
3359 minimum or maximum value in the range. Also, unless INIT is
3360 a simple expression, compare_values and possibly other functions
3361 in tree-vrp won't be able to handle it. */
3362 if (step == NULL_TREE
3363 || !is_gimple_min_invariant (step)
3364 || !valid_value_p (init))
3367 dir = scev_direction (chrec);
3368 if (/* Do not adjust ranges if we do not know whether the iv increases
3369 or decreases, ... */
3370 dir == EV_DIR_UNKNOWN
3371 /* ... or if it may wrap. */
3372 || scev_probably_wraps_p (init, step, stmt, get_chrec_loop (chrec),
3376 /* We use TYPE_MIN_VALUE and TYPE_MAX_VALUE here instead of
3377 negative_overflow_infinity and positive_overflow_infinity,
3378 because we have concluded that the loop probably does not
3381 type = TREE_TYPE (var);
3382 if (POINTER_TYPE_P (type) || !TYPE_MIN_VALUE (type))
3383 tmin = lower_bound_in_type (type, type);
3385 tmin = TYPE_MIN_VALUE (type);
3386 if (POINTER_TYPE_P (type) || !TYPE_MAX_VALUE (type))
3387 tmax = upper_bound_in_type (type, type);
3389 tmax = TYPE_MAX_VALUE (type);
3391 /* Try to use estimated number of iterations for the loop to constrain the
3392 final value in the evolution. */
3393 if (TREE_CODE (step) == INTEGER_CST
3394 && is_gimple_val (init)
3395 && (TREE_CODE (init) != SSA_NAME
3396 || get_value_range (init)->type == VR_RANGE))
3400 if (estimated_loop_iterations (loop, true, &nit))
3402 value_range_t maxvr = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
3404 bool unsigned_p = TYPE_UNSIGNED (TREE_TYPE (step));
3407 dtmp = double_int_mul_with_sign (tree_to_double_int (step), nit,
3408 unsigned_p, &overflow);
3409 /* If the multiplication overflowed we can't do a meaningful
3410 adjustment. Likewise if the result doesn't fit in the type
3411 of the induction variable. For a signed type we have to
3412 check whether the result has the expected signedness which
3413 is that of the step as number of iterations is unsigned. */
3415 && double_int_fits_to_tree_p (TREE_TYPE (init), dtmp)
3417 || ((dtmp.high ^ TREE_INT_CST_HIGH (step)) >= 0)))
3419 tem = double_int_to_tree (TREE_TYPE (init), dtmp);
3420 extract_range_from_binary_expr (&maxvr, PLUS_EXPR,
3421 TREE_TYPE (init), init, tem);
3422 /* Likewise if the addition did. */
3423 if (maxvr.type == VR_RANGE)
3432 if (vr->type == VR_VARYING || vr->type == VR_UNDEFINED)
3437 /* For VARYING or UNDEFINED ranges, just about anything we get
3438 from scalar evolutions should be better. */
3440 if (dir == EV_DIR_DECREASES)
3445 /* If we would create an invalid range, then just assume we
3446 know absolutely nothing. This may be over-conservative,
3447 but it's clearly safe, and should happen only in unreachable
3448 parts of code, or for invalid programs. */
3449 if (compare_values (min, max) == 1)
3452 set_value_range (vr, VR_RANGE, min, max, vr->equiv);
3454 else if (vr->type == VR_RANGE)
3459 if (dir == EV_DIR_DECREASES)
3461 /* INIT is the maximum value. If INIT is lower than VR->MAX
3462 but no smaller than VR->MIN, set VR->MAX to INIT. */
3463 if (compare_values (init, max) == -1)
3466 /* According to the loop information, the variable does not
3467 overflow. If we think it does, probably because of an
3468 overflow due to arithmetic on a different INF value,
3470 if (is_negative_overflow_infinity (min)
3471 || compare_values (min, tmin) == -1)
3477 /* If INIT is bigger than VR->MIN, set VR->MIN to INIT. */
3478 if (compare_values (init, min) == 1)
3481 if (is_positive_overflow_infinity (max)
3482 || compare_values (tmax, max) == -1)
3486 /* If we just created an invalid range with the minimum
3487 greater than the maximum, we fail conservatively.
3488 This should happen only in unreachable
3489 parts of code, or for invalid programs. */
3490 if (compare_values (min, max) == 1)
3493 set_value_range (vr, VR_RANGE, min, max, vr->equiv);
3497 /* Return true if VAR may overflow at STMT. This checks any available
3498 loop information to see if we can determine that VAR does not
3502 vrp_var_may_overflow (tree var, gimple stmt)
3505 tree chrec, init, step;
3507 if (current_loops == NULL)
3510 l = loop_containing_stmt (stmt);
3515 chrec = instantiate_parameters (l, analyze_scalar_evolution (l, var));
3516 if (TREE_CODE (chrec) != POLYNOMIAL_CHREC)
3519 init = initial_condition_in_loop_num (chrec, l->num);
3520 step = evolution_part_in_loop_num (chrec, l->num);
3522 if (step == NULL_TREE
3523 || !is_gimple_min_invariant (step)
3524 || !valid_value_p (init))
3527 /* If we get here, we know something useful about VAR based on the
3528 loop information. If it wraps, it may overflow. */
3530 if (scev_probably_wraps_p (init, step, stmt, get_chrec_loop (chrec),
3534 if (dump_file && (dump_flags & TDF_DETAILS) != 0)
3536 print_generic_expr (dump_file, var, 0);
3537 fprintf (dump_file, ": loop information indicates does not overflow\n");
3544 /* Given two numeric value ranges VR0, VR1 and a comparison code COMP:
3546 - Return BOOLEAN_TRUE_NODE if VR0 COMP VR1 always returns true for
3547 all the values in the ranges.
3549 - Return BOOLEAN_FALSE_NODE if the comparison always returns false.
3551 - Return NULL_TREE if it is not always possible to determine the
3552 value of the comparison.
3554 Also set *STRICT_OVERFLOW_P to indicate whether a range with an
3555 overflow infinity was used in the test. */
3559 compare_ranges (enum tree_code comp, value_range_t *vr0, value_range_t *vr1,
3560 bool *strict_overflow_p)
3562 /* VARYING or UNDEFINED ranges cannot be compared. */
3563 if (vr0->type == VR_VARYING
3564 || vr0->type == VR_UNDEFINED
3565 || vr1->type == VR_VARYING
3566 || vr1->type == VR_UNDEFINED)
3569 /* Anti-ranges need to be handled separately. */
3570 if (vr0->type == VR_ANTI_RANGE || vr1->type == VR_ANTI_RANGE)
3572 /* If both are anti-ranges, then we cannot compute any
3574 if (vr0->type == VR_ANTI_RANGE && vr1->type == VR_ANTI_RANGE)
3577 /* These comparisons are never statically computable. */
3584 /* Equality can be computed only between a range and an
3585 anti-range. ~[VAL1, VAL2] == [VAL1, VAL2] is always false. */
3586 if (vr0->type == VR_RANGE)
3588 /* To simplify processing, make VR0 the anti-range. */
3589 value_range_t *tmp = vr0;
3594 gcc_assert (comp == NE_EXPR || comp == EQ_EXPR);
3596 if (compare_values_warnv (vr0->min, vr1->min, strict_overflow_p) == 0
3597 && compare_values_warnv (vr0->max, vr1->max, strict_overflow_p) == 0)
3598 return (comp == NE_EXPR) ? boolean_true_node : boolean_false_node;
3603 if (!usable_range_p (vr0, strict_overflow_p)
3604 || !usable_range_p (vr1, strict_overflow_p))
3607 /* Simplify processing. If COMP is GT_EXPR or GE_EXPR, switch the
3608 operands around and change the comparison code. */
3609 if (comp == GT_EXPR || comp == GE_EXPR)
3612 comp = (comp == GT_EXPR) ? LT_EXPR : LE_EXPR;
3618 if (comp == EQ_EXPR)
3620 /* Equality may only be computed if both ranges represent
3621 exactly one value. */
3622 if (compare_values_warnv (vr0->min, vr0->max, strict_overflow_p) == 0
3623 && compare_values_warnv (vr1->min, vr1->max, strict_overflow_p) == 0)
3625 int cmp_min = compare_values_warnv (vr0->min, vr1->min,
3627 int cmp_max = compare_values_warnv (vr0->max, vr1->max,
3629 if (cmp_min == 0 && cmp_max == 0)
3630 return boolean_true_node;
3631 else if (cmp_min != -2 && cmp_max != -2)
3632 return boolean_false_node;
3634 /* If [V0_MIN, V1_MAX] < [V1_MIN, V1_MAX] then V0 != V1. */
3635 else if (compare_values_warnv (vr0->min, vr1->max,
3636 strict_overflow_p) == 1
3637 || compare_values_warnv (vr1->min, vr0->max,
3638 strict_overflow_p) == 1)
3639 return boolean_false_node;
3643 else if (comp == NE_EXPR)
3647 /* If VR0 is completely to the left or completely to the right
3648 of VR1, they are always different. Notice that we need to
3649 make sure that both comparisons yield similar results to
3650 avoid comparing values that cannot be compared at
3652 cmp1 = compare_values_warnv (vr0->max, vr1->min, strict_overflow_p);
3653 cmp2 = compare_values_warnv (vr0->min, vr1->max, strict_overflow_p);
3654 if ((cmp1 == -1 && cmp2 == -1) || (cmp1 == 1 && cmp2 == 1))
3655 return boolean_true_node;
3657 /* If VR0 and VR1 represent a single value and are identical,
3659 else if (compare_values_warnv (vr0->min, vr0->max,
3660 strict_overflow_p) == 0
3661 && compare_values_warnv (vr1->min, vr1->max,
3662 strict_overflow_p) == 0
3663 && compare_values_warnv (vr0->min, vr1->min,
3664 strict_overflow_p) == 0
3665 && compare_values_warnv (vr0->max, vr1->max,
3666 strict_overflow_p) == 0)
3667 return boolean_false_node;
3669 /* Otherwise, they may or may not be different. */
3673 else if (comp == LT_EXPR || comp == LE_EXPR)
3677 /* If VR0 is to the left of VR1, return true. */
3678 tst = compare_values_warnv (vr0->max, vr1->min, strict_overflow_p);
3679 if ((comp == LT_EXPR && tst == -1)
3680 || (comp == LE_EXPR && (tst == -1 || tst == 0)))
3682 if (overflow_infinity_range_p (vr0)
3683 || overflow_infinity_range_p (vr1))
3684 *strict_overflow_p = true;
3685 return boolean_true_node;
3688 /* If VR0 is to the right of VR1, return false. */
3689 tst = compare_values_warnv (vr0->min, vr1->max, strict_overflow_p);
3690 if ((comp == LT_EXPR && (tst == 0 || tst == 1))
3691 || (comp == LE_EXPR && tst == 1))
3693 if (overflow_infinity_range_p (vr0)
3694 || overflow_infinity_range_p (vr1))
3695 *strict_overflow_p = true;
3696 return boolean_false_node;
3699 /* Otherwise, we don't know. */
3707 /* Given a value range VR, a value VAL and a comparison code COMP, return
3708 BOOLEAN_TRUE_NODE if VR COMP VAL always returns true for all the
3709 values in VR. Return BOOLEAN_FALSE_NODE if the comparison
3710 always returns false. Return NULL_TREE if it is not always
3711 possible to determine the value of the comparison. Also set
3712 *STRICT_OVERFLOW_P to indicate whether a range with an overflow
3713 infinity was used in the test. */
3716 compare_range_with_value (enum tree_code comp, value_range_t *vr, tree val,
3717 bool *strict_overflow_p)
3719 if (vr->type == VR_VARYING || vr->type == VR_UNDEFINED)
3722 /* Anti-ranges need to be handled separately. */
3723 if (vr->type == VR_ANTI_RANGE)
3725 /* For anti-ranges, the only predicates that we can compute at
3726 compile time are equality and inequality. */
3733 /* ~[VAL_1, VAL_2] OP VAL is known if VAL_1 <= VAL <= VAL_2. */
3734 if (value_inside_range (val, vr->min, vr->max) == 1)
3735 return (comp == NE_EXPR) ? boolean_true_node : boolean_false_node;
3740 if (!usable_range_p (vr, strict_overflow_p))
3743 if (comp == EQ_EXPR)
3745 /* EQ_EXPR may only be computed if VR represents exactly
3747 if (compare_values_warnv (vr->min, vr->max, strict_overflow_p) == 0)
3749 int cmp = compare_values_warnv (vr->min, val, strict_overflow_p);
3751 return boolean_true_node;
3752 else if (cmp == -1 || cmp == 1 || cmp == 2)
3753 return boolean_false_node;
3755 else if (compare_values_warnv (val, vr->min, strict_overflow_p) == -1
3756 || compare_values_warnv (vr->max, val, strict_overflow_p) == -1)
3757 return boolean_false_node;
3761 else if (comp == NE_EXPR)
3763 /* If VAL is not inside VR, then they are always different. */
3764 if (compare_values_warnv (vr->max, val, strict_overflow_p) == -1
3765 || compare_values_warnv (vr->min, val, strict_overflow_p) == 1)
3766 return boolean_true_node;
3768 /* If VR represents exactly one value equal to VAL, then return
3770 if (compare_values_warnv (vr->min, vr->max, strict_overflow_p) == 0
3771 && compare_values_warnv (vr->min, val, strict_overflow_p) == 0)
3772 return boolean_false_node;
3774 /* Otherwise, they may or may not be different. */
3777 else if (comp == LT_EXPR || comp == LE_EXPR)
3781 /* If VR is to the left of VAL, return true. */
3782 tst = compare_values_warnv (vr->max, val, strict_overflow_p);
3783 if ((comp == LT_EXPR && tst == -1)
3784 || (comp == LE_EXPR && (tst == -1 || tst == 0)))
3786 if (overflow_infinity_range_p (vr))
3787 *strict_overflow_p = true;
3788 return boolean_true_node;
3791 /* If VR is to the right of VAL, return false. */
3792 tst = compare_values_warnv (vr->min, val, strict_overflow_p);
3793 if ((comp == LT_EXPR && (tst == 0 || tst == 1))
3794 || (comp == LE_EXPR && tst == 1))
3796 if (overflow_infinity_range_p (vr))
3797 *strict_overflow_p = true;
3798 return boolean_false_node;
3801 /* Otherwise, we don't know. */
3804 else if (comp == GT_EXPR || comp == GE_EXPR)
3808 /* If VR is to the right of VAL, return true. */
3809 tst = compare_values_warnv (vr->min, val, strict_overflow_p);
3810 if ((comp == GT_EXPR && tst == 1)
3811 || (comp == GE_EXPR && (tst == 0 || tst == 1)))
3813 if (overflow_infinity_range_p (vr))
3814 *strict_overflow_p = true;
3815 return boolean_true_node;
3818 /* If VR is to the left of VAL, return false. */
3819 tst = compare_values_warnv (vr->max, val, strict_overflow_p);
3820 if ((comp == GT_EXPR && (tst == -1 || tst == 0))
3821 || (comp == GE_EXPR && tst == -1))
3823 if (overflow_infinity_range_p (vr))
3824 *strict_overflow_p = true;
3825 return boolean_false_node;
3828 /* Otherwise, we don't know. */
3836 /* Debugging dumps. */
3838 void dump_value_range (FILE *, value_range_t *);
3839 void debug_value_range (value_range_t *);
3840 void dump_all_value_ranges (FILE *);
3841 void debug_all_value_ranges (void);
3842 void dump_vr_equiv (FILE *, bitmap);
3843 void debug_vr_equiv (bitmap);
3846 /* Dump value range VR to FILE. */
3849 dump_value_range (FILE *file, value_range_t *vr)
3852 fprintf (file, "[]");
3853 else if (vr->type == VR_UNDEFINED)
3854 fprintf (file, "UNDEFINED");
3855 else if (vr->type == VR_RANGE || vr->type == VR_ANTI_RANGE)
3857 tree type = TREE_TYPE (vr->min);
3859 fprintf (file, "%s[", (vr->type == VR_ANTI_RANGE) ? "~" : "");
3861 if (is_negative_overflow_infinity (vr->min))
3862 fprintf (file, "-INF(OVF)");
3863 else if (INTEGRAL_TYPE_P (type)
3864 && !TYPE_UNSIGNED (type)
3865 && vrp_val_is_min (vr->min))
3866 fprintf (file, "-INF");
3868 print_generic_expr (file, vr->min, 0);
3870 fprintf (file, ", ");
3872 if (is_positive_overflow_infinity (vr->max))
3873 fprintf (file, "+INF(OVF)");
3874 else if (INTEGRAL_TYPE_P (type)
3875 && vrp_val_is_max (vr->max))
3876 fprintf (file, "+INF");
3878 print_generic_expr (file, vr->max, 0);
3880 fprintf (file, "]");
3887 fprintf (file, " EQUIVALENCES: { ");
3889 EXECUTE_IF_SET_IN_BITMAP (vr->equiv, 0, i, bi)
3891 print_generic_expr (file, ssa_name (i), 0);
3892 fprintf (file, " ");
3896 fprintf (file, "} (%u elements)", c);
3899 else if (vr->type == VR_VARYING)
3900 fprintf (file, "VARYING");
3902 fprintf (file, "INVALID RANGE");
3906 /* Dump value range VR to stderr. */
3909 debug_value_range (value_range_t *vr)
3911 dump_value_range (stderr, vr);
3912 fprintf (stderr, "\n");
3916 /* Dump value ranges of all SSA_NAMEs to FILE. */
3919 dump_all_value_ranges (FILE *file)
3923 for (i = 0; i < num_vr_values; i++)
3927 print_generic_expr (file, ssa_name (i), 0);
3928 fprintf (file, ": ");
3929 dump_value_range (file, vr_value[i]);
3930 fprintf (file, "\n");
3934 fprintf (file, "\n");
3938 /* Dump all value ranges to stderr. */
3941 debug_all_value_ranges (void)
3943 dump_all_value_ranges (stderr);
3947 /* Given a COND_EXPR COND of the form 'V OP W', and an SSA name V,
3948 create a new SSA name N and return the assertion assignment
3949 'V = ASSERT_EXPR <V, V OP W>'. */
3952 build_assert_expr_for (tree cond, tree v)
3957 gcc_assert (TREE_CODE (v) == SSA_NAME);
3958 n = duplicate_ssa_name (v, NULL);
3960 if (COMPARISON_CLASS_P (cond))
3962 tree a = build2 (ASSERT_EXPR, TREE_TYPE (v), v, cond);
3963 assertion = gimple_build_assign (n, a);
3965 else if (TREE_CODE (cond) == SSA_NAME)
3967 /* Given V, build the assignment N = true. */
3968 gcc_assert (v == cond);
3969 assertion = gimple_build_assign (n, boolean_true_node);
3974 SSA_NAME_DEF_STMT (n) = assertion;
3976 /* The new ASSERT_EXPR, creates a new SSA name that replaces the
3977 operand of the ASSERT_EXPR. Register the new name and the old one
3978 in the replacement table so that we can fix the SSA web after
3979 adding all the ASSERT_EXPRs. */
3980 register_new_name_mapping (n, v);
3986 /* Return false if EXPR is a predicate expression involving floating
3990 fp_predicate (gimple stmt)
3992 GIMPLE_CHECK (stmt, GIMPLE_COND);
3994 return FLOAT_TYPE_P (TREE_TYPE (gimple_cond_lhs (stmt)));
3998 /* If the range of values taken by OP can be inferred after STMT executes,
3999 return the comparison code (COMP_CODE_P) and value (VAL_P) that
4000 describes the inferred range. Return true if a range could be
4004 infer_value_range (gimple stmt, tree op, enum tree_code *comp_code_p, tree *val_p)
4007 *comp_code_p = ERROR_MARK;
4009 /* Do not attempt to infer anything in names that flow through
4011 if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (op))
4014 /* Similarly, don't infer anything from statements that may throw
4016 if (stmt_could_throw_p (stmt))
4019 /* If STMT is the last statement of a basic block with no
4020 successors, there is no point inferring anything about any of its
4021 operands. We would not be able to find a proper insertion point
4022 for the assertion, anyway. */
4023 if (stmt_ends_bb_p (stmt) && EDGE_COUNT (gimple_bb (stmt)->succs) == 0)
4026 /* We can only assume that a pointer dereference will yield
4027 non-NULL if -fdelete-null-pointer-checks is enabled. */
4028 if (flag_delete_null_pointer_checks
4029 && POINTER_TYPE_P (TREE_TYPE (op))
4030 && gimple_code (stmt) != GIMPLE_ASM)
4032 unsigned num_uses, num_loads, num_stores;
4034 count_uses_and_derefs (op, stmt, &num_uses, &num_loads, &num_stores);
4035 if (num_loads + num_stores > 0)
4037 *val_p = build_int_cst (TREE_TYPE (op), 0);
4038 *comp_code_p = NE_EXPR;
4047 void dump_asserts_for (FILE *, tree);
4048 void debug_asserts_for (tree);
4049 void dump_all_asserts (FILE *);
4050 void debug_all_asserts (void);
4052 /* Dump all the registered assertions for NAME to FILE. */
4055 dump_asserts_for (FILE *file, tree name)
4059 fprintf (file, "Assertions to be inserted for ");
4060 print_generic_expr (file, name, 0);
4061 fprintf (file, "\n");
4063 loc = asserts_for[SSA_NAME_VERSION (name)];
4066 fprintf (file, "\t");
4067 print_gimple_stmt (file, gsi_stmt (loc->si), 0, 0);
4068 fprintf (file, "\n\tBB #%d", loc->bb->index);
4071 fprintf (file, "\n\tEDGE %d->%d", loc->e->src->index,
4072 loc->e->dest->index);
4073 dump_edge_info (file, loc->e, 0);
4075 fprintf (file, "\n\tPREDICATE: ");
4076 print_generic_expr (file, name, 0);
4077 fprintf (file, " %s ", tree_code_name[(int)loc->comp_code]);
4078 print_generic_expr (file, loc->val, 0);
4079 fprintf (file, "\n\n");
4083 fprintf (file, "\n");
4087 /* Dump all the registered assertions for NAME to stderr. */
4090 debug_asserts_for (tree name)
4092 dump_asserts_for (stderr, name);
4096 /* Dump all the registered assertions for all the names to FILE. */
4099 dump_all_asserts (FILE *file)
4104 fprintf (file, "\nASSERT_EXPRs to be inserted\n\n");
4105 EXECUTE_IF_SET_IN_BITMAP (need_assert_for, 0, i, bi)
4106 dump_asserts_for (file, ssa_name (i));
4107 fprintf (file, "\n");
4111 /* Dump all the registered assertions for all the names to stderr. */
4114 debug_all_asserts (void)
4116 dump_all_asserts (stderr);
4120 /* If NAME doesn't have an ASSERT_EXPR registered for asserting
4121 'EXPR COMP_CODE VAL' at a location that dominates block BB or
4122 E->DEST, then register this location as a possible insertion point
4123 for ASSERT_EXPR <NAME, EXPR COMP_CODE VAL>.
4125 BB, E and SI provide the exact insertion point for the new
4126 ASSERT_EXPR. If BB is NULL, then the ASSERT_EXPR is to be inserted
4127 on edge E. Otherwise, if E is NULL, the ASSERT_EXPR is inserted on
4128 BB. If SI points to a COND_EXPR or a SWITCH_EXPR statement, then E
4129 must not be NULL. */
4132 register_new_assert_for (tree name, tree expr,
4133 enum tree_code comp_code,
4137 gimple_stmt_iterator si)
4139 assert_locus_t n, loc, last_loc;
4140 basic_block dest_bb;
4142 gcc_checking_assert (bb == NULL || e == NULL);
4145 gcc_checking_assert (gimple_code (gsi_stmt (si)) != GIMPLE_COND
4146 && gimple_code (gsi_stmt (si)) != GIMPLE_SWITCH);
4148 /* Never build an assert comparing against an integer constant with
4149 TREE_OVERFLOW set. This confuses our undefined overflow warning
4151 if (TREE_CODE (val) == INTEGER_CST
4152 && TREE_OVERFLOW (val))
4153 val = build_int_cst_wide (TREE_TYPE (val),
4154 TREE_INT_CST_LOW (val), TREE_INT_CST_HIGH (val));
4156 /* The new assertion A will be inserted at BB or E. We need to
4157 determine if the new location is dominated by a previously
4158 registered location for A. If we are doing an edge insertion,
4159 assume that A will be inserted at E->DEST. Note that this is not
4162 If E is a critical edge, it will be split. But even if E is
4163 split, the new block will dominate the same set of blocks that
4166 The reverse, however, is not true, blocks dominated by E->DEST
4167 will not be dominated by the new block created to split E. So,
4168 if the insertion location is on a critical edge, we will not use
4169 the new location to move another assertion previously registered
4170 at a block dominated by E->DEST. */
4171 dest_bb = (bb) ? bb : e->dest;
4173 /* If NAME already has an ASSERT_EXPR registered for COMP_CODE and
4174 VAL at a block dominating DEST_BB, then we don't need to insert a new
4175 one. Similarly, if the same assertion already exists at a block
4176 dominated by DEST_BB and the new location is not on a critical
4177 edge, then update the existing location for the assertion (i.e.,
4178 move the assertion up in the dominance tree).
4180 Note, this is implemented as a simple linked list because there
4181 should not be more than a handful of assertions registered per
4182 name. If this becomes a performance problem, a table hashed by
4183 COMP_CODE and VAL could be implemented. */
4184 loc = asserts_for[SSA_NAME_VERSION (name)];
4188 if (loc->comp_code == comp_code
4190 || operand_equal_p (loc->val, val, 0))
4191 && (loc->expr == expr
4192 || operand_equal_p (loc->expr, expr, 0)))
4194 /* If the assertion NAME COMP_CODE VAL has already been
4195 registered at a basic block that dominates DEST_BB, then
4196 we don't need to insert the same assertion again. Note
4197 that we don't check strict dominance here to avoid
4198 replicating the same assertion inside the same basic
4199 block more than once (e.g., when a pointer is
4200 dereferenced several times inside a block).
4202 An exception to this rule are edge insertions. If the
4203 new assertion is to be inserted on edge E, then it will
4204 dominate all the other insertions that we may want to
4205 insert in DEST_BB. So, if we are doing an edge
4206 insertion, don't do this dominance check. */
4208 && dominated_by_p (CDI_DOMINATORS, dest_bb, loc->bb))
4211 /* Otherwise, if E is not a critical edge and DEST_BB
4212 dominates the existing location for the assertion, move
4213 the assertion up in the dominance tree by updating its
4214 location information. */
4215 if ((e == NULL || !EDGE_CRITICAL_P (e))
4216 && dominated_by_p (CDI_DOMINATORS, loc->bb, dest_bb))
4225 /* Update the last node of the list and move to the next one. */
4230 /* If we didn't find an assertion already registered for
4231 NAME COMP_CODE VAL, add a new one at the end of the list of
4232 assertions associated with NAME. */
4233 n = XNEW (struct assert_locus_d);
4237 n->comp_code = comp_code;
4245 asserts_for[SSA_NAME_VERSION (name)] = n;
4247 bitmap_set_bit (need_assert_for, SSA_NAME_VERSION (name));
4250 /* (COND_OP0 COND_CODE COND_OP1) is a predicate which uses NAME.
4251 Extract a suitable test code and value and store them into *CODE_P and
4252 *VAL_P so the predicate is normalized to NAME *CODE_P *VAL_P.
4254 If no extraction was possible, return FALSE, otherwise return TRUE.
4256 If INVERT is true, then we invert the result stored into *CODE_P. */
4259 extract_code_and_val_from_cond_with_ops (tree name, enum tree_code cond_code,
4260 tree cond_op0, tree cond_op1,
4261 bool invert, enum tree_code *code_p,
4264 enum tree_code comp_code;
4267 /* Otherwise, we have a comparison of the form NAME COMP VAL
4268 or VAL COMP NAME. */
4269 if (name == cond_op1)
4271 /* If the predicate is of the form VAL COMP NAME, flip
4272 COMP around because we need to register NAME as the
4273 first operand in the predicate. */
4274 comp_code = swap_tree_comparison (cond_code);
4279 /* The comparison is of the form NAME COMP VAL, so the
4280 comparison code remains unchanged. */
4281 comp_code = cond_code;
4285 /* Invert the comparison code as necessary. */
4287 comp_code = invert_tree_comparison (comp_code, 0);
4289 /* VRP does not handle float types. */
4290 if (SCALAR_FLOAT_TYPE_P (TREE_TYPE (val)))
4293 /* Do not register always-false predicates.
4294 FIXME: this works around a limitation in fold() when dealing with
4295 enumerations. Given 'enum { N1, N2 } x;', fold will not
4296 fold 'if (x > N2)' to 'if (0)'. */
4297 if ((comp_code == GT_EXPR || comp_code == LT_EXPR)
4298 && INTEGRAL_TYPE_P (TREE_TYPE (val)))
4300 tree min = TYPE_MIN_VALUE (TREE_TYPE (val));
4301 tree max = TYPE_MAX_VALUE (TREE_TYPE (val));
4303 if (comp_code == GT_EXPR
4305 || compare_values (val, max) == 0))
4308 if (comp_code == LT_EXPR
4310 || compare_values (val, min) == 0))
4313 *code_p = comp_code;
4318 /* Try to register an edge assertion for SSA name NAME on edge E for
4319 the condition COND contributing to the conditional jump pointed to by BSI.
4320 Invert the condition COND if INVERT is true.
4321 Return true if an assertion for NAME could be registered. */
4324 register_edge_assert_for_2 (tree name, edge e, gimple_stmt_iterator bsi,
4325 enum tree_code cond_code,
4326 tree cond_op0, tree cond_op1, bool invert)
4329 enum tree_code comp_code;
4330 bool retval = false;
4332 if (!extract_code_and_val_from_cond_with_ops (name, cond_code,
4335 invert, &comp_code, &val))
4338 /* Only register an ASSERT_EXPR if NAME was found in the sub-graph
4339 reachable from E. */
4340 if (live_on_edge (e, name)
4341 && !has_single_use (name))
4343 register_new_assert_for (name, name, comp_code, val, NULL, e, bsi);
4347 /* In the case of NAME <= CST and NAME being defined as
4348 NAME = (unsigned) NAME2 + CST2 we can assert NAME2 >= -CST2
4349 and NAME2 <= CST - CST2. We can do the same for NAME > CST.
4350 This catches range and anti-range tests. */
4351 if ((comp_code == LE_EXPR
4352 || comp_code == GT_EXPR)
4353 && TREE_CODE (val) == INTEGER_CST
4354 && TYPE_UNSIGNED (TREE_TYPE (val)))
4356 gimple def_stmt = SSA_NAME_DEF_STMT (name);
4357 tree cst2 = NULL_TREE, name2 = NULL_TREE, name3 = NULL_TREE;
4359 /* Extract CST2 from the (optional) addition. */
4360 if (is_gimple_assign (def_stmt)
4361 && gimple_assign_rhs_code (def_stmt) == PLUS_EXPR)
4363 name2 = gimple_assign_rhs1 (def_stmt);
4364 cst2 = gimple_assign_rhs2 (def_stmt);
4365 if (TREE_CODE (name2) == SSA_NAME
4366 && TREE_CODE (cst2) == INTEGER_CST)
4367 def_stmt = SSA_NAME_DEF_STMT (name2);
4370 /* Extract NAME2 from the (optional) sign-changing cast. */
4371 if (gimple_assign_cast_p (def_stmt))
4373 if (CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (def_stmt))
4374 && ! TYPE_UNSIGNED (TREE_TYPE (gimple_assign_rhs1 (def_stmt)))
4375 && (TYPE_PRECISION (gimple_expr_type (def_stmt))
4376 == TYPE_PRECISION (TREE_TYPE (gimple_assign_rhs1 (def_stmt)))))
4377 name3 = gimple_assign_rhs1 (def_stmt);
4380 /* If name3 is used later, create an ASSERT_EXPR for it. */
4381 if (name3 != NULL_TREE
4382 && TREE_CODE (name3) == SSA_NAME
4383 && (cst2 == NULL_TREE
4384 || TREE_CODE (cst2) == INTEGER_CST)
4385 && INTEGRAL_TYPE_P (TREE_TYPE (name3))
4386 && live_on_edge (e, name3)
4387 && !has_single_use (name3))
4391 /* Build an expression for the range test. */
4392 tmp = build1 (NOP_EXPR, TREE_TYPE (name), name3);
4393 if (cst2 != NULL_TREE)
4394 tmp = build2 (PLUS_EXPR, TREE_TYPE (name), tmp, cst2);
4398 fprintf (dump_file, "Adding assert for ");
4399 print_generic_expr (dump_file, name3, 0);
4400 fprintf (dump_file, " from ");
4401 print_generic_expr (dump_file, tmp, 0);
4402 fprintf (dump_file, "\n");
4405 register_new_assert_for (name3, tmp, comp_code, val, NULL, e, bsi);
4410 /* If name2 is used later, create an ASSERT_EXPR for it. */
4411 if (name2 != NULL_TREE
4412 && TREE_CODE (name2) == SSA_NAME
4413 && TREE_CODE (cst2) == INTEGER_CST
4414 && INTEGRAL_TYPE_P (TREE_TYPE (name2))
4415 && live_on_edge (e, name2)
4416 && !has_single_use (name2))
4420 /* Build an expression for the range test. */
4422 if (TREE_TYPE (name) != TREE_TYPE (name2))
4423 tmp = build1 (NOP_EXPR, TREE_TYPE (name), tmp);
4424 if (cst2 != NULL_TREE)
4425 tmp = build2 (PLUS_EXPR, TREE_TYPE (name), tmp, cst2);
4429 fprintf (dump_file, "Adding assert for ");
4430 print_generic_expr (dump_file, name2, 0);
4431 fprintf (dump_file, " from ");
4432 print_generic_expr (dump_file, tmp, 0);
4433 fprintf (dump_file, "\n");
4436 register_new_assert_for (name2, tmp, comp_code, val, NULL, e, bsi);
4445 /* OP is an operand of a truth value expression which is known to have
4446 a particular value. Register any asserts for OP and for any
4447 operands in OP's defining statement.
4449 If CODE is EQ_EXPR, then we want to register OP is zero (false),
4450 if CODE is NE_EXPR, then we want to register OP is nonzero (true). */
4453 register_edge_assert_for_1 (tree op, enum tree_code code,
4454 edge e, gimple_stmt_iterator bsi)
4456 bool retval = false;
4459 enum tree_code rhs_code;
4461 /* We only care about SSA_NAMEs. */
4462 if (TREE_CODE (op) != SSA_NAME)
4465 /* We know that OP will have a zero or nonzero value. If OP is used
4466 more than once go ahead and register an assert for OP.
4468 The FOUND_IN_SUBGRAPH support is not helpful in this situation as
4469 it will always be set for OP (because OP is used in a COND_EXPR in
4471 if (!has_single_use (op))
4473 val = build_int_cst (TREE_TYPE (op), 0);
4474 register_new_assert_for (op, op, code, val, NULL, e, bsi);
4478 /* Now look at how OP is set. If it's set from a comparison,
4479 a truth operation or some bit operations, then we may be able
4480 to register information about the operands of that assignment. */
4481 op_def = SSA_NAME_DEF_STMT (op);
4482 if (gimple_code (op_def) != GIMPLE_ASSIGN)
4485 rhs_code = gimple_assign_rhs_code (op_def);
4487 if (TREE_CODE_CLASS (rhs_code) == tcc_comparison)
4489 bool invert = (code == EQ_EXPR ? true : false);
4490 tree op0 = gimple_assign_rhs1 (op_def);
4491 tree op1 = gimple_assign_rhs2 (op_def);
4493 if (TREE_CODE (op0) == SSA_NAME)
4494 retval |= register_edge_assert_for_2 (op0, e, bsi, rhs_code, op0, op1,
4496 if (TREE_CODE (op1) == SSA_NAME)
4497 retval |= register_edge_assert_for_2 (op1, e, bsi, rhs_code, op0, op1,
4500 else if ((code == NE_EXPR
4501 && gimple_assign_rhs_code (op_def) == BIT_AND_EXPR)
4503 && gimple_assign_rhs_code (op_def) == BIT_IOR_EXPR))
4505 /* Recurse on each operand. */
4506 retval |= register_edge_assert_for_1 (gimple_assign_rhs1 (op_def),
4508 retval |= register_edge_assert_for_1 (gimple_assign_rhs2 (op_def),
4511 else if (gimple_assign_rhs_code (op_def) == BIT_NOT_EXPR
4512 && TYPE_PRECISION (TREE_TYPE (gimple_assign_lhs (op_def))) == 1)
4514 /* Recurse, flipping CODE. */
4515 code = invert_tree_comparison (code, false);
4516 retval |= register_edge_assert_for_1 (gimple_assign_rhs1 (op_def),
4519 else if (gimple_assign_rhs_code (op_def) == SSA_NAME)
4521 /* Recurse through the copy. */
4522 retval |= register_edge_assert_for_1 (gimple_assign_rhs1 (op_def),
4525 else if (CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (op_def)))
4527 /* Recurse through the type conversion. */
4528 retval |= register_edge_assert_for_1 (gimple_assign_rhs1 (op_def),
4535 /* Try to register an edge assertion for SSA name NAME on edge E for
4536 the condition COND contributing to the conditional jump pointed to by SI.
4537 Return true if an assertion for NAME could be registered. */
4540 register_edge_assert_for (tree name, edge e, gimple_stmt_iterator si,
4541 enum tree_code cond_code, tree cond_op0,
4545 enum tree_code comp_code;
4546 bool retval = false;
4547 bool is_else_edge = (e->flags & EDGE_FALSE_VALUE) != 0;
4549 /* Do not attempt to infer anything in names that flow through
4551 if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (name))
4554 if (!extract_code_and_val_from_cond_with_ops (name, cond_code,
4560 /* Register ASSERT_EXPRs for name. */
4561 retval |= register_edge_assert_for_2 (name, e, si, cond_code, cond_op0,
4562 cond_op1, is_else_edge);
4565 /* If COND is effectively an equality test of an SSA_NAME against
4566 the value zero or one, then we may be able to assert values
4567 for SSA_NAMEs which flow into COND. */
4569 /* In the case of NAME == 1 or NAME != 0, for BIT_AND_EXPR defining
4570 statement of NAME we can assert both operands of the BIT_AND_EXPR
4571 have nonzero value. */
4572 if (((comp_code == EQ_EXPR && integer_onep (val))
4573 || (comp_code == NE_EXPR && integer_zerop (val))))
4575 gimple def_stmt = SSA_NAME_DEF_STMT (name);
4577 if (is_gimple_assign (def_stmt)
4578 && gimple_assign_rhs_code (def_stmt) == BIT_AND_EXPR)
4580 tree op0 = gimple_assign_rhs1 (def_stmt);
4581 tree op1 = gimple_assign_rhs2 (def_stmt);
4582 retval |= register_edge_assert_for_1 (op0, NE_EXPR, e, si);
4583 retval |= register_edge_assert_for_1 (op1, NE_EXPR, e, si);
4587 /* In the case of NAME == 0 or NAME != 1, for BIT_IOR_EXPR defining
4588 statement of NAME we can assert both operands of the BIT_IOR_EXPR
4590 if (((comp_code == EQ_EXPR && integer_zerop (val))
4591 || (comp_code == NE_EXPR && integer_onep (val))))
4593 gimple def_stmt = SSA_NAME_DEF_STMT (name);
4595 /* For BIT_IOR_EXPR only if NAME == 0 both operands have
4596 necessarily zero value, or if type-precision is one. */
4597 if (is_gimple_assign (def_stmt)
4598 && (gimple_assign_rhs_code (def_stmt) == BIT_IOR_EXPR
4599 && (TYPE_PRECISION (TREE_TYPE (name)) == 1
4600 || comp_code == EQ_EXPR)))
4602 tree op0 = gimple_assign_rhs1 (def_stmt);
4603 tree op1 = gimple_assign_rhs2 (def_stmt);
4604 retval |= register_edge_assert_for_1 (op0, EQ_EXPR, e, si);
4605 retval |= register_edge_assert_for_1 (op1, EQ_EXPR, e, si);
4613 /* Determine whether the outgoing edges of BB should receive an
4614 ASSERT_EXPR for each of the operands of BB's LAST statement.
4615 The last statement of BB must be a COND_EXPR.
4617 If any of the sub-graphs rooted at BB have an interesting use of
4618 the predicate operands, an assert location node is added to the
4619 list of assertions for the corresponding operands. */
4622 find_conditional_asserts (basic_block bb, gimple last)
4625 gimple_stmt_iterator bsi;
4631 need_assert = false;
4632 bsi = gsi_for_stmt (last);
4634 /* Look for uses of the operands in each of the sub-graphs
4635 rooted at BB. We need to check each of the outgoing edges
4636 separately, so that we know what kind of ASSERT_EXPR to
4638 FOR_EACH_EDGE (e, ei, bb->succs)
4643 /* Register the necessary assertions for each operand in the
4644 conditional predicate. */
4645 FOR_EACH_SSA_TREE_OPERAND (op, last, iter, SSA_OP_USE)
4647 need_assert |= register_edge_assert_for (op, e, bsi,
4648 gimple_cond_code (last),
4649 gimple_cond_lhs (last),
4650 gimple_cond_rhs (last));
4663 /* Compare two case labels sorting first by the destination bb index
4664 and then by the case value. */
4667 compare_case_labels (const void *p1, const void *p2)
4669 const struct case_info *ci1 = (const struct case_info *) p1;
4670 const struct case_info *ci2 = (const struct case_info *) p2;
4671 int idx1 = ci1->bb->index;
4672 int idx2 = ci2->bb->index;
4676 else if (idx1 == idx2)
4678 /* Make sure the default label is first in a group. */
4679 if (!CASE_LOW (ci1->expr))
4681 else if (!CASE_LOW (ci2->expr))
4684 return tree_int_cst_compare (CASE_LOW (ci1->expr),
4685 CASE_LOW (ci2->expr));
4691 /* Determine whether the outgoing edges of BB should receive an
4692 ASSERT_EXPR for each of the operands of BB's LAST statement.
4693 The last statement of BB must be a SWITCH_EXPR.
4695 If any of the sub-graphs rooted at BB have an interesting use of
4696 the predicate operands, an assert location node is added to the
4697 list of assertions for the corresponding operands. */
4700 find_switch_asserts (basic_block bb, gimple last)
4703 gimple_stmt_iterator bsi;
4706 struct case_info *ci;
4707 size_t n = gimple_switch_num_labels (last);
4708 #if GCC_VERSION >= 4000
4711 /* Work around GCC 3.4 bug (PR 37086). */
4712 volatile unsigned int idx;
4715 need_assert = false;
4716 bsi = gsi_for_stmt (last);
4717 op = gimple_switch_index (last);
4718 if (TREE_CODE (op) != SSA_NAME)
4721 /* Build a vector of case labels sorted by destination label. */
4722 ci = XNEWVEC (struct case_info, n);
4723 for (idx = 0; idx < n; ++idx)
4725 ci[idx].expr = gimple_switch_label (last, idx);
4726 ci[idx].bb = label_to_block (CASE_LABEL (ci[idx].expr));
4728 qsort (ci, n, sizeof (struct case_info), compare_case_labels);
4730 for (idx = 0; idx < n; ++idx)
4733 tree cl = ci[idx].expr;
4734 basic_block cbb = ci[idx].bb;
4736 min = CASE_LOW (cl);
4737 max = CASE_HIGH (cl);
4739 /* If there are multiple case labels with the same destination
4740 we need to combine them to a single value range for the edge. */
4741 if (idx + 1 < n && cbb == ci[idx + 1].bb)
4743 /* Skip labels until the last of the group. */
4746 } while (idx < n && cbb == ci[idx].bb);
4749 /* Pick up the maximum of the case label range. */
4750 if (CASE_HIGH (ci[idx].expr))
4751 max = CASE_HIGH (ci[idx].expr);
4753 max = CASE_LOW (ci[idx].expr);
4756 /* Nothing to do if the range includes the default label until we
4757 can register anti-ranges. */
4758 if (min == NULL_TREE)
4761 /* Find the edge to register the assert expr on. */
4762 e = find_edge (bb, cbb);
4764 /* Register the necessary assertions for the operand in the
4766 need_assert |= register_edge_assert_for (op, e, bsi,
4767 max ? GE_EXPR : EQ_EXPR,
4769 fold_convert (TREE_TYPE (op),
4773 need_assert |= register_edge_assert_for (op, e, bsi, LE_EXPR,
4775 fold_convert (TREE_TYPE (op),
4785 /* Traverse all the statements in block BB looking for statements that
4786 may generate useful assertions for the SSA names in their operand.
4787 If a statement produces a useful assertion A for name N_i, then the
4788 list of assertions already generated for N_i is scanned to
4789 determine if A is actually needed.
4791 If N_i already had the assertion A at a location dominating the
4792 current location, then nothing needs to be done. Otherwise, the
4793 new location for A is recorded instead.
4795 1- For every statement S in BB, all the variables used by S are
4796 added to bitmap FOUND_IN_SUBGRAPH.
4798 2- If statement S uses an operand N in a way that exposes a known
4799 value range for N, then if N was not already generated by an
4800 ASSERT_EXPR, create a new assert location for N. For instance,
4801 if N is a pointer and the statement dereferences it, we can
4802 assume that N is not NULL.
4804 3- COND_EXPRs are a special case of #2. We can derive range
4805 information from the predicate but need to insert different
4806 ASSERT_EXPRs for each of the sub-graphs rooted at the
4807 conditional block. If the last statement of BB is a conditional
4808 expression of the form 'X op Y', then
4810 a) Remove X and Y from the set FOUND_IN_SUBGRAPH.
4812 b) If the conditional is the only entry point to the sub-graph
4813 corresponding to the THEN_CLAUSE, recurse into it. On
4814 return, if X and/or Y are marked in FOUND_IN_SUBGRAPH, then
4815 an ASSERT_EXPR is added for the corresponding variable.
4817 c) Repeat step (b) on the ELSE_CLAUSE.
4819 d) Mark X and Y in FOUND_IN_SUBGRAPH.
4828 In this case, an assertion on the THEN clause is useful to
4829 determine that 'a' is always 9 on that edge. However, an assertion
4830 on the ELSE clause would be unnecessary.
4832 4- If BB does not end in a conditional expression, then we recurse
4833 into BB's dominator children.
4835 At the end of the recursive traversal, every SSA name will have a
4836 list of locations where ASSERT_EXPRs should be added. When a new
4837 location for name N is found, it is registered by calling
4838 register_new_assert_for. That function keeps track of all the
4839 registered assertions to prevent adding unnecessary assertions.
4840 For instance, if a pointer P_4 is dereferenced more than once in a
4841 dominator tree, only the location dominating all the dereference of
4842 P_4 will receive an ASSERT_EXPR.
4844 If this function returns true, then it means that there are names
4845 for which we need to generate ASSERT_EXPRs. Those assertions are
4846 inserted by process_assert_insertions. */
4849 find_assert_locations_1 (basic_block bb, sbitmap live)
4851 gimple_stmt_iterator si;
4856 need_assert = false;
4857 last = last_stmt (bb);
4859 /* If BB's last statement is a conditional statement involving integer
4860 operands, determine if we need to add ASSERT_EXPRs. */
4862 && gimple_code (last) == GIMPLE_COND
4863 && !fp_predicate (last)
4864 && !ZERO_SSA_OPERANDS (last, SSA_OP_USE))
4865 need_assert |= find_conditional_asserts (bb, last);
4867 /* If BB's last statement is a switch statement involving integer
4868 operands, determine if we need to add ASSERT_EXPRs. */
4870 && gimple_code (last) == GIMPLE_SWITCH
4871 && !ZERO_SSA_OPERANDS (last, SSA_OP_USE))
4872 need_assert |= find_switch_asserts (bb, last);
4874 /* Traverse all the statements in BB marking used names and looking
4875 for statements that may infer assertions for their used operands. */
4876 for (si = gsi_start_bb (bb); !gsi_end_p (si); gsi_next (&si))
4882 stmt = gsi_stmt (si);
4884 if (is_gimple_debug (stmt))
4887 /* See if we can derive an assertion for any of STMT's operands. */
4888 FOR_EACH_SSA_TREE_OPERAND (op, stmt, i, SSA_OP_USE)
4891 enum tree_code comp_code;
4893 /* Mark OP in our live bitmap. */
4894 SET_BIT (live, SSA_NAME_VERSION (op));
4896 /* If OP is used in such a way that we can infer a value
4897 range for it, and we don't find a previous assertion for
4898 it, create a new assertion location node for OP. */
4899 if (infer_value_range (stmt, op, &comp_code, &value))
4901 /* If we are able to infer a nonzero value range for OP,
4902 then walk backwards through the use-def chain to see if OP
4903 was set via a typecast.
4905 If so, then we can also infer a nonzero value range
4906 for the operand of the NOP_EXPR. */
4907 if (comp_code == NE_EXPR && integer_zerop (value))
4910 gimple def_stmt = SSA_NAME_DEF_STMT (t);
4912 while (is_gimple_assign (def_stmt)
4913 && gimple_assign_rhs_code (def_stmt) == NOP_EXPR
4915 (gimple_assign_rhs1 (def_stmt)) == SSA_NAME
4917 (TREE_TYPE (gimple_assign_rhs1 (def_stmt))))
4919 t = gimple_assign_rhs1 (def_stmt);
4920 def_stmt = SSA_NAME_DEF_STMT (t);
4922 /* Note we want to register the assert for the
4923 operand of the NOP_EXPR after SI, not after the
4925 if (! has_single_use (t))
4927 register_new_assert_for (t, t, comp_code, value,
4934 /* If OP is used only once, namely in this STMT, don't
4935 bother creating an ASSERT_EXPR for it. Such an
4936 ASSERT_EXPR would do nothing but increase compile time. */
4937 if (!has_single_use (op))
4939 register_new_assert_for (op, op, comp_code, value,
4947 /* Traverse all PHI nodes in BB marking used operands. */
4948 for (si = gsi_start_phis (bb); !gsi_end_p(si); gsi_next (&si))
4950 use_operand_p arg_p;
4952 phi = gsi_stmt (si);
4954 FOR_EACH_PHI_ARG (arg_p, phi, i, SSA_OP_USE)
4956 tree arg = USE_FROM_PTR (arg_p);
4957 if (TREE_CODE (arg) == SSA_NAME)
4958 SET_BIT (live, SSA_NAME_VERSION (arg));
4965 /* Do an RPO walk over the function computing SSA name liveness
4966 on-the-fly and deciding on assert expressions to insert.
4967 Returns true if there are assert expressions to be inserted. */
4970 find_assert_locations (void)
4972 int *rpo = XCNEWVEC (int, last_basic_block + NUM_FIXED_BLOCKS);
4973 int *bb_rpo = XCNEWVEC (int, last_basic_block + NUM_FIXED_BLOCKS);
4974 int *last_rpo = XCNEWVEC (int, last_basic_block + NUM_FIXED_BLOCKS);
4978 live = XCNEWVEC (sbitmap, last_basic_block + NUM_FIXED_BLOCKS);
4979 rpo_cnt = pre_and_rev_post_order_compute (NULL, rpo, false);
4980 for (i = 0; i < rpo_cnt; ++i)
4983 need_asserts = false;
4984 for (i = rpo_cnt-1; i >= 0; --i)
4986 basic_block bb = BASIC_BLOCK (rpo[i]);
4992 live[rpo[i]] = sbitmap_alloc (num_ssa_names);
4993 sbitmap_zero (live[rpo[i]]);
4996 /* Process BB and update the live information with uses in
4998 need_asserts |= find_assert_locations_1 (bb, live[rpo[i]]);
5000 /* Merge liveness into the predecessor blocks and free it. */
5001 if (!sbitmap_empty_p (live[rpo[i]]))
5004 FOR_EACH_EDGE (e, ei, bb->preds)
5006 int pred = e->src->index;
5007 if (e->flags & EDGE_DFS_BACK)
5012 live[pred] = sbitmap_alloc (num_ssa_names);
5013 sbitmap_zero (live[pred]);
5015 sbitmap_a_or_b (live[pred], live[pred], live[rpo[i]]);
5017 if (bb_rpo[pred] < pred_rpo)
5018 pred_rpo = bb_rpo[pred];
5021 /* Record the RPO number of the last visited block that needs
5022 live information from this block. */
5023 last_rpo[rpo[i]] = pred_rpo;
5027 sbitmap_free (live[rpo[i]]);
5028 live[rpo[i]] = NULL;
5031 /* We can free all successors live bitmaps if all their
5032 predecessors have been visited already. */
5033 FOR_EACH_EDGE (e, ei, bb->succs)
5034 if (last_rpo[e->dest->index] == i
5035 && live[e->dest->index])
5037 sbitmap_free (live[e->dest->index]);
5038 live[e->dest->index] = NULL;
5043 XDELETEVEC (bb_rpo);
5044 XDELETEVEC (last_rpo);
5045 for (i = 0; i < last_basic_block + NUM_FIXED_BLOCKS; ++i)
5047 sbitmap_free (live[i]);
5050 return need_asserts;
5053 /* Create an ASSERT_EXPR for NAME and insert it in the location
5054 indicated by LOC. Return true if we made any edge insertions. */
5057 process_assert_insertions_for (tree name, assert_locus_t loc)
5059 /* Build the comparison expression NAME_i COMP_CODE VAL. */
5066 /* If we have X <=> X do not insert an assert expr for that. */
5067 if (loc->expr == loc->val)
5070 cond = build2 (loc->comp_code, boolean_type_node, loc->expr, loc->val);
5071 assert_stmt = build_assert_expr_for (cond, name);
5074 /* We have been asked to insert the assertion on an edge. This
5075 is used only by COND_EXPR and SWITCH_EXPR assertions. */
5076 gcc_checking_assert (gimple_code (gsi_stmt (loc->si)) == GIMPLE_COND
5077 || (gimple_code (gsi_stmt (loc->si))
5080 gsi_insert_on_edge (loc->e, assert_stmt);
5084 /* Otherwise, we can insert right after LOC->SI iff the
5085 statement must not be the last statement in the block. */
5086 stmt = gsi_stmt (loc->si);
5087 if (!stmt_ends_bb_p (stmt))
5089 gsi_insert_after (&loc->si, assert_stmt, GSI_SAME_STMT);
5093 /* If STMT must be the last statement in BB, we can only insert new
5094 assertions on the non-abnormal edge out of BB. Note that since
5095 STMT is not control flow, there may only be one non-abnormal edge
5097 FOR_EACH_EDGE (e, ei, loc->bb->succs)
5098 if (!(e->flags & EDGE_ABNORMAL))
5100 gsi_insert_on_edge (e, assert_stmt);
5108 /* Process all the insertions registered for every name N_i registered
5109 in NEED_ASSERT_FOR. The list of assertions to be inserted are
5110 found in ASSERTS_FOR[i]. */
5113 process_assert_insertions (void)
5117 bool update_edges_p = false;
5118 int num_asserts = 0;
5120 if (dump_file && (dump_flags & TDF_DETAILS))
5121 dump_all_asserts (dump_file);
5123 EXECUTE_IF_SET_IN_BITMAP (need_assert_for, 0, i, bi)
5125 assert_locus_t loc = asserts_for[i];
5130 assert_locus_t next = loc->next;
5131 update_edges_p |= process_assert_insertions_for (ssa_name (i), loc);
5139 gsi_commit_edge_inserts ();
5141 statistics_counter_event (cfun, "Number of ASSERT_EXPR expressions inserted",
5146 /* Traverse the flowgraph looking for conditional jumps to insert range
5147 expressions. These range expressions are meant to provide information
5148 to optimizations that need to reason in terms of value ranges. They
5149 will not be expanded into RTL. For instance, given:
5158 this pass will transform the code into:
5164 x = ASSERT_EXPR <x, x < y>
5169 y = ASSERT_EXPR <y, x <= y>
5173 The idea is that once copy and constant propagation have run, other
5174 optimizations will be able to determine what ranges of values can 'x'
5175 take in different paths of the code, simply by checking the reaching
5176 definition of 'x'. */
5179 insert_range_assertions (void)
5181 need_assert_for = BITMAP_ALLOC (NULL);
5182 asserts_for = XCNEWVEC (assert_locus_t, num_ssa_names);
5184 calculate_dominance_info (CDI_DOMINATORS);
5186 if (find_assert_locations ())
5188 process_assert_insertions ();
5189 update_ssa (TODO_update_ssa_no_phi);
5192 if (dump_file && (dump_flags & TDF_DETAILS))
5194 fprintf (dump_file, "\nSSA form after inserting ASSERT_EXPRs\n");
5195 dump_function_to_file (current_function_decl, dump_file, dump_flags);
5199 BITMAP_FREE (need_assert_for);
5202 /* Checks one ARRAY_REF in REF, located at LOCUS. Ignores flexible arrays
5203 and "struct" hacks. If VRP can determine that the
5204 array subscript is a constant, check if it is outside valid
5205 range. If the array subscript is a RANGE, warn if it is
5206 non-overlapping with valid range.
5207 IGNORE_OFF_BY_ONE is true if the ARRAY_REF is inside a ADDR_EXPR. */
5210 check_array_ref (location_t location, tree ref, bool ignore_off_by_one)
5212 value_range_t* vr = NULL;
5213 tree low_sub, up_sub;
5214 tree low_bound, up_bound, up_bound_p1;
5217 if (TREE_NO_WARNING (ref))
5220 low_sub = up_sub = TREE_OPERAND (ref, 1);
5221 up_bound = array_ref_up_bound (ref);
5223 /* Can not check flexible arrays. */
5225 || TREE_CODE (up_bound) != INTEGER_CST)
5228 /* Accesses to trailing arrays via pointers may access storage
5229 beyond the types array bounds. */
5230 base = get_base_address (ref);
5231 if (base && TREE_CODE (base) == MEM_REF)
5233 tree cref, next = NULL_TREE;
5235 if (TREE_CODE (TREE_OPERAND (ref, 0)) != COMPONENT_REF)
5238 cref = TREE_OPERAND (ref, 0);
5239 if (TREE_CODE (TREE_TYPE (TREE_OPERAND (cref, 0))) == RECORD_TYPE)
5240 for (next = DECL_CHAIN (TREE_OPERAND (cref, 1));
5241 next && TREE_CODE (next) != FIELD_DECL;
5242 next = DECL_CHAIN (next))
5245 /* If this is the last field in a struct type or a field in a
5246 union type do not warn. */
5251 low_bound = array_ref_low_bound (ref);
5252 up_bound_p1 = int_const_binop (PLUS_EXPR, up_bound, integer_one_node);
5254 if (TREE_CODE (low_sub) == SSA_NAME)
5256 vr = get_value_range (low_sub);
5257 if (vr->type == VR_RANGE || vr->type == VR_ANTI_RANGE)
5259 low_sub = vr->type == VR_RANGE ? vr->max : vr->min;
5260 up_sub = vr->type == VR_RANGE ? vr->min : vr->max;
5264 if (vr && vr->type == VR_ANTI_RANGE)
5266 if (TREE_CODE (up_sub) == INTEGER_CST
5267 && tree_int_cst_lt (up_bound, up_sub)
5268 && TREE_CODE (low_sub) == INTEGER_CST
5269 && tree_int_cst_lt (low_sub, low_bound))
5271 warning_at (location, OPT_Warray_bounds,
5272 "array subscript is outside array bounds");
5273 TREE_NO_WARNING (ref) = 1;
5276 else if (TREE_CODE (up_sub) == INTEGER_CST
5277 && (ignore_off_by_one
5278 ? (tree_int_cst_lt (up_bound, up_sub)
5279 && !tree_int_cst_equal (up_bound_p1, up_sub))
5280 : (tree_int_cst_lt (up_bound, up_sub)
5281 || tree_int_cst_equal (up_bound_p1, up_sub))))
5283 warning_at (location, OPT_Warray_bounds,
5284 "array subscript is above array bounds");
5285 TREE_NO_WARNING (ref) = 1;
5287 else if (TREE_CODE (low_sub) == INTEGER_CST
5288 && tree_int_cst_lt (low_sub, low_bound))
5290 warning_at (location, OPT_Warray_bounds,
5291 "array subscript is below array bounds");
5292 TREE_NO_WARNING (ref) = 1;
5296 /* Searches if the expr T, located at LOCATION computes
5297 address of an ARRAY_REF, and call check_array_ref on it. */
5300 search_for_addr_array (tree t, location_t location)
5302 while (TREE_CODE (t) == SSA_NAME)
5304 gimple g = SSA_NAME_DEF_STMT (t);
5306 if (gimple_code (g) != GIMPLE_ASSIGN)
5309 if (get_gimple_rhs_class (gimple_assign_rhs_code (g))
5310 != GIMPLE_SINGLE_RHS)
5313 t = gimple_assign_rhs1 (g);
5317 /* We are only interested in addresses of ARRAY_REF's. */
5318 if (TREE_CODE (t) != ADDR_EXPR)
5321 /* Check each ARRAY_REFs in the reference chain. */
5324 if (TREE_CODE (t) == ARRAY_REF)
5325 check_array_ref (location, t, true /*ignore_off_by_one*/);
5327 t = TREE_OPERAND (t, 0);
5329 while (handled_component_p (t));
5331 if (TREE_CODE (t) == MEM_REF
5332 && TREE_CODE (TREE_OPERAND (t, 0)) == ADDR_EXPR
5333 && !TREE_NO_WARNING (t))
5335 tree tem = TREE_OPERAND (TREE_OPERAND (t, 0), 0);
5336 tree low_bound, up_bound, el_sz;
5338 if (TREE_CODE (TREE_TYPE (tem)) != ARRAY_TYPE
5339 || TREE_CODE (TREE_TYPE (TREE_TYPE (tem))) == ARRAY_TYPE
5340 || !TYPE_DOMAIN (TREE_TYPE (tem)))
5343 low_bound = TYPE_MIN_VALUE (TYPE_DOMAIN (TREE_TYPE (tem)));
5344 up_bound = TYPE_MAX_VALUE (TYPE_DOMAIN (TREE_TYPE (tem)));
5345 el_sz = TYPE_SIZE_UNIT (TREE_TYPE (TREE_TYPE (tem)));
5347 || TREE_CODE (low_bound) != INTEGER_CST
5349 || TREE_CODE (up_bound) != INTEGER_CST
5351 || TREE_CODE (el_sz) != INTEGER_CST)
5354 idx = mem_ref_offset (t);
5355 idx = double_int_sdiv (idx, tree_to_double_int (el_sz), TRUNC_DIV_EXPR);
5356 if (double_int_scmp (idx, double_int_zero) < 0)
5358 warning_at (location, OPT_Warray_bounds,
5359 "array subscript is below array bounds");
5360 TREE_NO_WARNING (t) = 1;
5362 else if (double_int_scmp (idx,
5365 (tree_to_double_int (up_bound),
5367 (tree_to_double_int (low_bound))),
5368 double_int_one)) > 0)
5370 warning_at (location, OPT_Warray_bounds,
5371 "array subscript is above array bounds");
5372 TREE_NO_WARNING (t) = 1;
5377 /* walk_tree() callback that checks if *TP is
5378 an ARRAY_REF inside an ADDR_EXPR (in which an array
5379 subscript one outside the valid range is allowed). Call
5380 check_array_ref for each ARRAY_REF found. The location is
5384 check_array_bounds (tree *tp, int *walk_subtree, void *data)
5387 struct walk_stmt_info *wi = (struct walk_stmt_info *) data;
5388 location_t location;
5390 if (EXPR_HAS_LOCATION (t))
5391 location = EXPR_LOCATION (t);
5394 location_t *locp = (location_t *) wi->info;
5398 *walk_subtree = TRUE;
5400 if (TREE_CODE (t) == ARRAY_REF)
5401 check_array_ref (location, t, false /*ignore_off_by_one*/);
5403 if (TREE_CODE (t) == MEM_REF
5404 || (TREE_CODE (t) == RETURN_EXPR && TREE_OPERAND (t, 0)))
5405 search_for_addr_array (TREE_OPERAND (t, 0), location);
5407 if (TREE_CODE (t) == ADDR_EXPR)
5408 *walk_subtree = FALSE;
5413 /* Walk over all statements of all reachable BBs and call check_array_bounds
5417 check_all_array_refs (void)
5420 gimple_stmt_iterator si;
5426 bool executable = false;
5428 /* Skip blocks that were found to be unreachable. */
5429 FOR_EACH_EDGE (e, ei, bb->preds)
5430 executable |= !!(e->flags & EDGE_EXECUTABLE);
5434 for (si = gsi_start_bb (bb); !gsi_end_p (si); gsi_next (&si))
5436 gimple stmt = gsi_stmt (si);
5437 struct walk_stmt_info wi;
5438 if (!gimple_has_location (stmt))
5441 if (is_gimple_call (stmt))
5444 size_t n = gimple_call_num_args (stmt);
5445 for (i = 0; i < n; i++)
5447 tree arg = gimple_call_arg (stmt, i);
5448 search_for_addr_array (arg, gimple_location (stmt));
5453 memset (&wi, 0, sizeof (wi));
5454 wi.info = CONST_CAST (void *, (const void *)
5455 gimple_location_ptr (stmt));
5457 walk_gimple_op (gsi_stmt (si),
5465 /* Convert range assertion expressions into the implied copies and
5466 copy propagate away the copies. Doing the trivial copy propagation
5467 here avoids the need to run the full copy propagation pass after
5470 FIXME, this will eventually lead to copy propagation removing the
5471 names that had useful range information attached to them. For
5472 instance, if we had the assertion N_i = ASSERT_EXPR <N_j, N_j > 3>,
5473 then N_i will have the range [3, +INF].
5475 However, by converting the assertion into the implied copy
5476 operation N_i = N_j, we will then copy-propagate N_j into the uses
5477 of N_i and lose the range information. We may want to hold on to
5478 ASSERT_EXPRs a little while longer as the ranges could be used in
5479 things like jump threading.
5481 The problem with keeping ASSERT_EXPRs around is that passes after
5482 VRP need to handle them appropriately.
5484 Another approach would be to make the range information a first
5485 class property of the SSA_NAME so that it can be queried from
5486 any pass. This is made somewhat more complex by the need for
5487 multiple ranges to be associated with one SSA_NAME. */
5490 remove_range_assertions (void)
5493 gimple_stmt_iterator si;
5495 /* Note that the BSI iterator bump happens at the bottom of the
5496 loop and no bump is necessary if we're removing the statement
5497 referenced by the current BSI. */
5499 for (si = gsi_start_bb (bb); !gsi_end_p (si);)
5501 gimple stmt = gsi_stmt (si);
5504 if (is_gimple_assign (stmt)
5505 && gimple_assign_rhs_code (stmt) == ASSERT_EXPR)
5507 tree rhs = gimple_assign_rhs1 (stmt);
5509 tree cond = fold (ASSERT_EXPR_COND (rhs));
5510 use_operand_p use_p;
5511 imm_use_iterator iter;
5513 gcc_assert (cond != boolean_false_node);
5515 /* Propagate the RHS into every use of the LHS. */
5516 var = ASSERT_EXPR_VAR (rhs);
5517 FOR_EACH_IMM_USE_STMT (use_stmt, iter,
5518 gimple_assign_lhs (stmt))
5519 FOR_EACH_IMM_USE_ON_STMT (use_p, iter)
5521 SET_USE (use_p, var);
5522 gcc_assert (TREE_CODE (var) == SSA_NAME);
5525 /* And finally, remove the copy, it is not needed. */
5526 gsi_remove (&si, true);
5527 release_defs (stmt);
5535 /* Return true if STMT is interesting for VRP. */
5538 stmt_interesting_for_vrp (gimple stmt)
5540 if (gimple_code (stmt) == GIMPLE_PHI
5541 && is_gimple_reg (gimple_phi_result (stmt))
5542 && (INTEGRAL_TYPE_P (TREE_TYPE (gimple_phi_result (stmt)))
5543 || POINTER_TYPE_P (TREE_TYPE (gimple_phi_result (stmt)))))
5545 else if (is_gimple_assign (stmt) || is_gimple_call (stmt))
5547 tree lhs = gimple_get_lhs (stmt);
5549 /* In general, assignments with virtual operands are not useful
5550 for deriving ranges, with the obvious exception of calls to
5551 builtin functions. */
5552 if (lhs && TREE_CODE (lhs) == SSA_NAME
5553 && (INTEGRAL_TYPE_P (TREE_TYPE (lhs))
5554 || POINTER_TYPE_P (TREE_TYPE (lhs)))
5555 && ((is_gimple_call (stmt)
5556 && gimple_call_fndecl (stmt) != NULL_TREE
5557 && DECL_BUILT_IN (gimple_call_fndecl (stmt)))
5558 || !gimple_vuse (stmt)))
5561 else if (gimple_code (stmt) == GIMPLE_COND
5562 || gimple_code (stmt) == GIMPLE_SWITCH)
5569 /* Initialize local data structures for VRP. */
5572 vrp_initialize (void)
5576 values_propagated = false;
5577 num_vr_values = num_ssa_names;
5578 vr_value = XCNEWVEC (value_range_t *, num_vr_values);
5579 vr_phi_edge_counts = XCNEWVEC (int, num_ssa_names);
5583 gimple_stmt_iterator si;
5585 for (si = gsi_start_phis (bb); !gsi_end_p (si); gsi_next (&si))
5587 gimple phi = gsi_stmt (si);
5588 if (!stmt_interesting_for_vrp (phi))
5590 tree lhs = PHI_RESULT (phi);
5591 set_value_range_to_varying (get_value_range (lhs));
5592 prop_set_simulate_again (phi, false);
5595 prop_set_simulate_again (phi, true);
5598 for (si = gsi_start_bb (bb); !gsi_end_p (si); gsi_next (&si))
5600 gimple stmt = gsi_stmt (si);
5602 /* If the statement is a control insn, then we do not
5603 want to avoid simulating the statement once. Failure
5604 to do so means that those edges will never get added. */
5605 if (stmt_ends_bb_p (stmt))
5606 prop_set_simulate_again (stmt, true);
5607 else if (!stmt_interesting_for_vrp (stmt))
5611 FOR_EACH_SSA_TREE_OPERAND (def, stmt, i, SSA_OP_DEF)
5612 set_value_range_to_varying (get_value_range (def));
5613 prop_set_simulate_again (stmt, false);
5616 prop_set_simulate_again (stmt, true);
5621 /* Return the singleton value-range for NAME or NAME. */
5624 vrp_valueize (tree name)
5626 if (TREE_CODE (name) == SSA_NAME)
5628 value_range_t *vr = get_value_range (name);
5629 if (vr->type == VR_RANGE
5630 && (vr->min == vr->max
5631 || operand_equal_p (vr->min, vr->max, 0)))
5637 /* Visit assignment STMT. If it produces an interesting range, record
5638 the SSA name in *OUTPUT_P. */
5640 static enum ssa_prop_result
5641 vrp_visit_assignment_or_call (gimple stmt, tree *output_p)
5645 enum gimple_code code = gimple_code (stmt);
5646 lhs = gimple_get_lhs (stmt);
5648 /* We only keep track of ranges in integral and pointer types. */
5649 if (TREE_CODE (lhs) == SSA_NAME
5650 && ((INTEGRAL_TYPE_P (TREE_TYPE (lhs))
5651 /* It is valid to have NULL MIN/MAX values on a type. See
5652 build_range_type. */
5653 && TYPE_MIN_VALUE (TREE_TYPE (lhs))
5654 && TYPE_MAX_VALUE (TREE_TYPE (lhs)))
5655 || POINTER_TYPE_P (TREE_TYPE (lhs))))
5657 value_range_t new_vr = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
5659 /* Try folding the statement to a constant first. */
5660 tree tem = gimple_fold_stmt_to_constant (stmt, vrp_valueize);
5661 if (tem && !is_overflow_infinity (tem))
5662 set_value_range (&new_vr, VR_RANGE, tem, tem, NULL);
5663 /* Then dispatch to value-range extracting functions. */
5664 else if (code == GIMPLE_CALL)
5665 extract_range_basic (&new_vr, stmt);
5667 extract_range_from_assignment (&new_vr, stmt);
5669 if (update_value_range (lhs, &new_vr))
5673 if (dump_file && (dump_flags & TDF_DETAILS))
5675 fprintf (dump_file, "Found new range for ");
5676 print_generic_expr (dump_file, lhs, 0);
5677 fprintf (dump_file, ": ");
5678 dump_value_range (dump_file, &new_vr);
5679 fprintf (dump_file, "\n\n");
5682 if (new_vr.type == VR_VARYING)
5683 return SSA_PROP_VARYING;
5685 return SSA_PROP_INTERESTING;
5688 return SSA_PROP_NOT_INTERESTING;
5691 /* Every other statement produces no useful ranges. */
5692 FOR_EACH_SSA_TREE_OPERAND (def, stmt, iter, SSA_OP_DEF)
5693 set_value_range_to_varying (get_value_range (def));
5695 return SSA_PROP_VARYING;
5698 /* Helper that gets the value range of the SSA_NAME with version I
5699 or a symbolic range containing the SSA_NAME only if the value range
5700 is varying or undefined. */
5702 static inline value_range_t
5703 get_vr_for_comparison (int i)
5705 value_range_t vr = *get_value_range (ssa_name (i));
5707 /* If name N_i does not have a valid range, use N_i as its own
5708 range. This allows us to compare against names that may
5709 have N_i in their ranges. */
5710 if (vr.type == VR_VARYING || vr.type == VR_UNDEFINED)
5713 vr.min = ssa_name (i);
5714 vr.max = ssa_name (i);
5720 /* Compare all the value ranges for names equivalent to VAR with VAL
5721 using comparison code COMP. Return the same value returned by
5722 compare_range_with_value, including the setting of
5723 *STRICT_OVERFLOW_P. */
5726 compare_name_with_value (enum tree_code comp, tree var, tree val,
5727 bool *strict_overflow_p)
5733 int used_strict_overflow;
5735 value_range_t equiv_vr;
5737 /* Get the set of equivalences for VAR. */
5738 e = get_value_range (var)->equiv;
5740 /* Start at -1. Set it to 0 if we do a comparison without relying
5741 on overflow, or 1 if all comparisons rely on overflow. */
5742 used_strict_overflow = -1;
5744 /* Compare vars' value range with val. */
5745 equiv_vr = get_vr_for_comparison (SSA_NAME_VERSION (var));
5747 retval = compare_range_with_value (comp, &equiv_vr, val, &sop);
5749 used_strict_overflow = sop ? 1 : 0;
5751 /* If the equiv set is empty we have done all work we need to do. */
5755 && used_strict_overflow > 0)
5756 *strict_overflow_p = true;
5760 EXECUTE_IF_SET_IN_BITMAP (e, 0, i, bi)
5762 equiv_vr = get_vr_for_comparison (i);
5764 t = compare_range_with_value (comp, &equiv_vr, val, &sop);
5767 /* If we get different answers from different members
5768 of the equivalence set this check must be in a dead
5769 code region. Folding it to a trap representation
5770 would be correct here. For now just return don't-know. */
5780 used_strict_overflow = 0;
5781 else if (used_strict_overflow < 0)
5782 used_strict_overflow = 1;
5787 && used_strict_overflow > 0)
5788 *strict_overflow_p = true;
5794 /* Given a comparison code COMP and names N1 and N2, compare all the
5795 ranges equivalent to N1 against all the ranges equivalent to N2
5796 to determine the value of N1 COMP N2. Return the same value
5797 returned by compare_ranges. Set *STRICT_OVERFLOW_P to indicate
5798 whether we relied on an overflow infinity in the comparison. */
5802 compare_names (enum tree_code comp, tree n1, tree n2,
5803 bool *strict_overflow_p)
5807 bitmap_iterator bi1, bi2;
5809 int used_strict_overflow;
5810 static bitmap_obstack *s_obstack = NULL;
5811 static bitmap s_e1 = NULL, s_e2 = NULL;
5813 /* Compare the ranges of every name equivalent to N1 against the
5814 ranges of every name equivalent to N2. */
5815 e1 = get_value_range (n1)->equiv;
5816 e2 = get_value_range (n2)->equiv;
5818 /* Use the fake bitmaps if e1 or e2 are not available. */
5819 if (s_obstack == NULL)
5821 s_obstack = XNEW (bitmap_obstack);
5822 bitmap_obstack_initialize (s_obstack);
5823 s_e1 = BITMAP_ALLOC (s_obstack);
5824 s_e2 = BITMAP_ALLOC (s_obstack);
5831 /* Add N1 and N2 to their own set of equivalences to avoid
5832 duplicating the body of the loop just to check N1 and N2
5834 bitmap_set_bit (e1, SSA_NAME_VERSION (n1));
5835 bitmap_set_bit (e2, SSA_NAME_VERSION (n2));
5837 /* If the equivalence sets have a common intersection, then the two
5838 names can be compared without checking their ranges. */
5839 if (bitmap_intersect_p (e1, e2))
5841 bitmap_clear_bit (e1, SSA_NAME_VERSION (n1));
5842 bitmap_clear_bit (e2, SSA_NAME_VERSION (n2));
5844 return (comp == EQ_EXPR || comp == GE_EXPR || comp == LE_EXPR)
5846 : boolean_false_node;
5849 /* Start at -1. Set it to 0 if we do a comparison without relying
5850 on overflow, or 1 if all comparisons rely on overflow. */
5851 used_strict_overflow = -1;
5853 /* Otherwise, compare all the equivalent ranges. First, add N1 and
5854 N2 to their own set of equivalences to avoid duplicating the body
5855 of the loop just to check N1 and N2 ranges. */
5856 EXECUTE_IF_SET_IN_BITMAP (e1, 0, i1, bi1)
5858 value_range_t vr1 = get_vr_for_comparison (i1);
5860 t = retval = NULL_TREE;
5861 EXECUTE_IF_SET_IN_BITMAP (e2, 0, i2, bi2)
5865 value_range_t vr2 = get_vr_for_comparison (i2);
5867 t = compare_ranges (comp, &vr1, &vr2, &sop);
5870 /* If we get different answers from different members
5871 of the equivalence set this check must be in a dead
5872 code region. Folding it to a trap representation
5873 would be correct here. For now just return don't-know. */
5877 bitmap_clear_bit (e1, SSA_NAME_VERSION (n1));
5878 bitmap_clear_bit (e2, SSA_NAME_VERSION (n2));
5884 used_strict_overflow = 0;
5885 else if (used_strict_overflow < 0)
5886 used_strict_overflow = 1;
5892 bitmap_clear_bit (e1, SSA_NAME_VERSION (n1));
5893 bitmap_clear_bit (e2, SSA_NAME_VERSION (n2));
5894 if (used_strict_overflow > 0)
5895 *strict_overflow_p = true;
5900 /* None of the equivalent ranges are useful in computing this
5902 bitmap_clear_bit (e1, SSA_NAME_VERSION (n1));
5903 bitmap_clear_bit (e2, SSA_NAME_VERSION (n2));
5907 /* Helper function for vrp_evaluate_conditional_warnv. */
5910 vrp_evaluate_conditional_warnv_with_ops_using_ranges (enum tree_code code,
5912 bool * strict_overflow_p)
5914 value_range_t *vr0, *vr1;
5916 vr0 = (TREE_CODE (op0) == SSA_NAME) ? get_value_range (op0) : NULL;
5917 vr1 = (TREE_CODE (op1) == SSA_NAME) ? get_value_range (op1) : NULL;
5920 return compare_ranges (code, vr0, vr1, strict_overflow_p);
5921 else if (vr0 && vr1 == NULL)
5922 return compare_range_with_value (code, vr0, op1, strict_overflow_p);
5923 else if (vr0 == NULL && vr1)
5924 return (compare_range_with_value
5925 (swap_tree_comparison (code), vr1, op0, strict_overflow_p));
5929 /* Helper function for vrp_evaluate_conditional_warnv. */
5932 vrp_evaluate_conditional_warnv_with_ops (enum tree_code code, tree op0,
5933 tree op1, bool use_equiv_p,
5934 bool *strict_overflow_p, bool *only_ranges)
5938 *only_ranges = true;
5940 /* We only deal with integral and pointer types. */
5941 if (!INTEGRAL_TYPE_P (TREE_TYPE (op0))
5942 && !POINTER_TYPE_P (TREE_TYPE (op0)))
5948 && (ret = vrp_evaluate_conditional_warnv_with_ops_using_ranges
5949 (code, op0, op1, strict_overflow_p)))
5951 *only_ranges = false;
5952 if (TREE_CODE (op0) == SSA_NAME && TREE_CODE (op1) == SSA_NAME)
5953 return compare_names (code, op0, op1, strict_overflow_p);
5954 else if (TREE_CODE (op0) == SSA_NAME)
5955 return compare_name_with_value (code, op0, op1, strict_overflow_p);
5956 else if (TREE_CODE (op1) == SSA_NAME)
5957 return (compare_name_with_value
5958 (swap_tree_comparison (code), op1, op0, strict_overflow_p));
5961 return vrp_evaluate_conditional_warnv_with_ops_using_ranges (code, op0, op1,
5966 /* Given (CODE OP0 OP1) within STMT, try to simplify it based on value range
5967 information. Return NULL if the conditional can not be evaluated.
5968 The ranges of all the names equivalent with the operands in COND
5969 will be used when trying to compute the value. If the result is
5970 based on undefined signed overflow, issue a warning if
5974 vrp_evaluate_conditional (enum tree_code code, tree op0, tree op1, gimple stmt)
5980 /* Some passes and foldings leak constants with overflow flag set
5981 into the IL. Avoid doing wrong things with these and bail out. */
5982 if ((TREE_CODE (op0) == INTEGER_CST
5983 && TREE_OVERFLOW (op0))
5984 || (TREE_CODE (op1) == INTEGER_CST
5985 && TREE_OVERFLOW (op1)))
5989 ret = vrp_evaluate_conditional_warnv_with_ops (code, op0, op1, true, &sop,
5994 enum warn_strict_overflow_code wc;
5995 const char* warnmsg;
5997 if (is_gimple_min_invariant (ret))
5999 wc = WARN_STRICT_OVERFLOW_CONDITIONAL;
6000 warnmsg = G_("assuming signed overflow does not occur when "
6001 "simplifying conditional to constant");
6005 wc = WARN_STRICT_OVERFLOW_COMPARISON;
6006 warnmsg = G_("assuming signed overflow does not occur when "
6007 "simplifying conditional");
6010 if (issue_strict_overflow_warning (wc))
6012 location_t location;
6014 if (!gimple_has_location (stmt))
6015 location = input_location;
6017 location = gimple_location (stmt);
6018 warning_at (location, OPT_Wstrict_overflow, "%s", warnmsg);
6022 if (warn_type_limits
6023 && ret && only_ranges
6024 && TREE_CODE_CLASS (code) == tcc_comparison
6025 && TREE_CODE (op0) == SSA_NAME)
6027 /* If the comparison is being folded and the operand on the LHS
6028 is being compared against a constant value that is outside of
6029 the natural range of OP0's type, then the predicate will
6030 always fold regardless of the value of OP0. If -Wtype-limits
6031 was specified, emit a warning. */
6032 tree type = TREE_TYPE (op0);
6033 value_range_t *vr0 = get_value_range (op0);
6035 if (vr0->type != VR_VARYING
6036 && INTEGRAL_TYPE_P (type)
6037 && vrp_val_is_min (vr0->min)
6038 && vrp_val_is_max (vr0->max)
6039 && is_gimple_min_invariant (op1))
6041 location_t location;
6043 if (!gimple_has_location (stmt))
6044 location = input_location;
6046 location = gimple_location (stmt);
6048 warning_at (location, OPT_Wtype_limits,
6050 ? G_("comparison always false "
6051 "due to limited range of data type")
6052 : G_("comparison always true "
6053 "due to limited range of data type"));
6061 /* Visit conditional statement STMT. If we can determine which edge
6062 will be taken out of STMT's basic block, record it in
6063 *TAKEN_EDGE_P and return SSA_PROP_INTERESTING. Otherwise, return
6064 SSA_PROP_VARYING. */
6066 static enum ssa_prop_result
6067 vrp_visit_cond_stmt (gimple stmt, edge *taken_edge_p)
6072 *taken_edge_p = NULL;
6074 if (dump_file && (dump_flags & TDF_DETAILS))
6079 fprintf (dump_file, "\nVisiting conditional with predicate: ");
6080 print_gimple_stmt (dump_file, stmt, 0, 0);
6081 fprintf (dump_file, "\nWith known ranges\n");
6083 FOR_EACH_SSA_TREE_OPERAND (use, stmt, i, SSA_OP_USE)
6085 fprintf (dump_file, "\t");
6086 print_generic_expr (dump_file, use, 0);
6087 fprintf (dump_file, ": ");
6088 dump_value_range (dump_file, vr_value[SSA_NAME_VERSION (use)]);
6091 fprintf (dump_file, "\n");
6094 /* Compute the value of the predicate COND by checking the known
6095 ranges of each of its operands.
6097 Note that we cannot evaluate all the equivalent ranges here
6098 because those ranges may not yet be final and with the current
6099 propagation strategy, we cannot determine when the value ranges
6100 of the names in the equivalence set have changed.
6102 For instance, given the following code fragment
6106 i_14 = ASSERT_EXPR <i_5, i_5 != 0>
6110 Assume that on the first visit to i_14, i_5 has the temporary
6111 range [8, 8] because the second argument to the PHI function is
6112 not yet executable. We derive the range ~[0, 0] for i_14 and the
6113 equivalence set { i_5 }. So, when we visit 'if (i_14 == 1)' for
6114 the first time, since i_14 is equivalent to the range [8, 8], we
6115 determine that the predicate is always false.
6117 On the next round of propagation, i_13 is determined to be
6118 VARYING, which causes i_5 to drop down to VARYING. So, another
6119 visit to i_14 is scheduled. In this second visit, we compute the
6120 exact same range and equivalence set for i_14, namely ~[0, 0] and
6121 { i_5 }. But we did not have the previous range for i_5
6122 registered, so vrp_visit_assignment thinks that the range for
6123 i_14 has not changed. Therefore, the predicate 'if (i_14 == 1)'
6124 is not visited again, which stops propagation from visiting
6125 statements in the THEN clause of that if().
6127 To properly fix this we would need to keep the previous range
6128 value for the names in the equivalence set. This way we would've
6129 discovered that from one visit to the other i_5 changed from
6130 range [8, 8] to VR_VARYING.
6132 However, fixing this apparent limitation may not be worth the
6133 additional checking. Testing on several code bases (GCC, DLV,
6134 MICO, TRAMP3D and SPEC2000) showed that doing this results in
6135 4 more predicates folded in SPEC. */
6138 val = vrp_evaluate_conditional_warnv_with_ops (gimple_cond_code (stmt),
6139 gimple_cond_lhs (stmt),
6140 gimple_cond_rhs (stmt),
6145 *taken_edge_p = find_taken_edge (gimple_bb (stmt), val);
6148 if (dump_file && (dump_flags & TDF_DETAILS))
6150 "\nIgnoring predicate evaluation because "
6151 "it assumes that signed overflow is undefined");
6156 if (dump_file && (dump_flags & TDF_DETAILS))
6158 fprintf (dump_file, "\nPredicate evaluates to: ");
6159 if (val == NULL_TREE)
6160 fprintf (dump_file, "DON'T KNOW\n");
6162 print_generic_stmt (dump_file, val, 0);
6165 return (*taken_edge_p) ? SSA_PROP_INTERESTING : SSA_PROP_VARYING;
6168 /* Searches the case label vector VEC for the index *IDX of the CASE_LABEL
6169 that includes the value VAL. The search is restricted to the range
6170 [START_IDX, n - 1] where n is the size of VEC.
6172 If there is a CASE_LABEL for VAL, its index is placed in IDX and true is
6175 If there is no CASE_LABEL for VAL and there is one that is larger than VAL,
6176 it is placed in IDX and false is returned.
6178 If VAL is larger than any CASE_LABEL, n is placed on IDX and false is
6182 find_case_label_index (gimple stmt, size_t start_idx, tree val, size_t *idx)
6184 size_t n = gimple_switch_num_labels (stmt);
6187 /* Find case label for minimum of the value range or the next one.
6188 At each iteration we are searching in [low, high - 1]. */
6190 for (low = start_idx, high = n; high != low; )
6194 /* Note that i != high, so we never ask for n. */
6195 size_t i = (high + low) / 2;
6196 t = gimple_switch_label (stmt, i);
6198 /* Cache the result of comparing CASE_LOW and val. */
6199 cmp = tree_int_cst_compare (CASE_LOW (t), val);
6203 /* Ranges cannot be empty. */
6212 if (CASE_HIGH (t) != NULL
6213 && tree_int_cst_compare (CASE_HIGH (t), val) >= 0)
6225 /* Searches the case label vector VEC for the range of CASE_LABELs that is used
6226 for values between MIN and MAX. The first index is placed in MIN_IDX. The
6227 last index is placed in MAX_IDX. If the range of CASE_LABELs is empty
6228 then MAX_IDX < MIN_IDX.
6229 Returns true if the default label is not needed. */
6232 find_case_label_range (gimple stmt, tree min, tree max, size_t *min_idx,
6236 bool min_take_default = !find_case_label_index (stmt, 1, min, &i);
6237 bool max_take_default = !find_case_label_index (stmt, i, max, &j);
6241 && max_take_default)
6243 /* Only the default case label reached.
6244 Return an empty range. */
6251 bool take_default = min_take_default || max_take_default;
6255 if (max_take_default)
6258 /* If the case label range is continuous, we do not need
6259 the default case label. Verify that. */
6260 high = CASE_LOW (gimple_switch_label (stmt, i));
6261 if (CASE_HIGH (gimple_switch_label (stmt, i)))
6262 high = CASE_HIGH (gimple_switch_label (stmt, i));
6263 for (k = i + 1; k <= j; ++k)
6265 low = CASE_LOW (gimple_switch_label (stmt, k));
6266 if (!integer_onep (int_const_binop (MINUS_EXPR, low, high)))
6268 take_default = true;
6272 if (CASE_HIGH (gimple_switch_label (stmt, k)))
6273 high = CASE_HIGH (gimple_switch_label (stmt, k));
6278 return !take_default;
6282 /* Visit switch statement STMT. If we can determine which edge
6283 will be taken out of STMT's basic block, record it in
6284 *TAKEN_EDGE_P and return SSA_PROP_INTERESTING. Otherwise, return
6285 SSA_PROP_VARYING. */
6287 static enum ssa_prop_result
6288 vrp_visit_switch_stmt (gimple stmt, edge *taken_edge_p)
6292 size_t i = 0, j = 0;
6295 *taken_edge_p = NULL;
6296 op = gimple_switch_index (stmt);
6297 if (TREE_CODE (op) != SSA_NAME)
6298 return SSA_PROP_VARYING;
6300 vr = get_value_range (op);
6301 if (dump_file && (dump_flags & TDF_DETAILS))
6303 fprintf (dump_file, "\nVisiting switch expression with operand ");
6304 print_generic_expr (dump_file, op, 0);
6305 fprintf (dump_file, " with known range ");
6306 dump_value_range (dump_file, vr);
6307 fprintf (dump_file, "\n");
6310 if (vr->type != VR_RANGE
6311 || symbolic_range_p (vr))
6312 return SSA_PROP_VARYING;
6314 /* Find the single edge that is taken from the switch expression. */
6315 take_default = !find_case_label_range (stmt, vr->min, vr->max, &i, &j);
6317 /* Check if the range spans no CASE_LABEL. If so, we only reach the default
6321 gcc_assert (take_default);
6322 val = gimple_switch_default_label (stmt);
6326 /* Check if labels with index i to j and maybe the default label
6327 are all reaching the same label. */
6329 val = gimple_switch_label (stmt, i);
6331 && CASE_LABEL (gimple_switch_default_label (stmt))
6332 != CASE_LABEL (val))
6334 if (dump_file && (dump_flags & TDF_DETAILS))
6335 fprintf (dump_file, " not a single destination for this "
6337 return SSA_PROP_VARYING;
6339 for (++i; i <= j; ++i)
6341 if (CASE_LABEL (gimple_switch_label (stmt, i)) != CASE_LABEL (val))
6343 if (dump_file && (dump_flags & TDF_DETAILS))
6344 fprintf (dump_file, " not a single destination for this "
6346 return SSA_PROP_VARYING;
6351 *taken_edge_p = find_edge (gimple_bb (stmt),
6352 label_to_block (CASE_LABEL (val)));
6354 if (dump_file && (dump_flags & TDF_DETAILS))
6356 fprintf (dump_file, " will take edge to ");
6357 print_generic_stmt (dump_file, CASE_LABEL (val), 0);
6360 return SSA_PROP_INTERESTING;
6364 /* Evaluate statement STMT. If the statement produces a useful range,
6365 return SSA_PROP_INTERESTING and record the SSA name with the
6366 interesting range into *OUTPUT_P.
6368 If STMT is a conditional branch and we can determine its truth
6369 value, the taken edge is recorded in *TAKEN_EDGE_P.
6371 If STMT produces a varying value, return SSA_PROP_VARYING. */
6373 static enum ssa_prop_result
6374 vrp_visit_stmt (gimple stmt, edge *taken_edge_p, tree *output_p)
6379 if (dump_file && (dump_flags & TDF_DETAILS))
6381 fprintf (dump_file, "\nVisiting statement:\n");
6382 print_gimple_stmt (dump_file, stmt, 0, dump_flags);
6383 fprintf (dump_file, "\n");
6386 if (!stmt_interesting_for_vrp (stmt))
6387 gcc_assert (stmt_ends_bb_p (stmt));
6388 else if (is_gimple_assign (stmt) || is_gimple_call (stmt))
6390 /* In general, assignments with virtual operands are not useful
6391 for deriving ranges, with the obvious exception of calls to
6392 builtin functions. */
6393 if ((is_gimple_call (stmt)
6394 && gimple_call_fndecl (stmt) != NULL_TREE
6395 && DECL_BUILT_IN (gimple_call_fndecl (stmt)))
6396 || !gimple_vuse (stmt))
6397 return vrp_visit_assignment_or_call (stmt, output_p);
6399 else if (gimple_code (stmt) == GIMPLE_COND)
6400 return vrp_visit_cond_stmt (stmt, taken_edge_p);
6401 else if (gimple_code (stmt) == GIMPLE_SWITCH)
6402 return vrp_visit_switch_stmt (stmt, taken_edge_p);
6404 /* All other statements produce nothing of interest for VRP, so mark
6405 their outputs varying and prevent further simulation. */
6406 FOR_EACH_SSA_TREE_OPERAND (def, stmt, iter, SSA_OP_DEF)
6407 set_value_range_to_varying (get_value_range (def));
6409 return SSA_PROP_VARYING;
6413 /* Meet operation for value ranges. Given two value ranges VR0 and
6414 VR1, store in VR0 a range that contains both VR0 and VR1. This
6415 may not be the smallest possible such range. */
6418 vrp_meet (value_range_t *vr0, value_range_t *vr1)
6420 if (vr0->type == VR_UNDEFINED)
6422 /* Drop equivalences. See PR53465. */
6423 set_value_range (vr0, vr1->type, vr1->min, vr1->max, NULL);
6427 if (vr1->type == VR_UNDEFINED)
6429 /* VR0 already has the resulting range, just drop equivalences.
6432 bitmap_clear (vr0->equiv);
6436 if (vr0->type == VR_VARYING)
6438 /* Nothing to do. VR0 already has the resulting range. */
6442 if (vr1->type == VR_VARYING)
6444 set_value_range_to_varying (vr0);
6448 if (vr0->type == VR_RANGE && vr1->type == VR_RANGE)
6453 /* Compute the convex hull of the ranges. The lower limit of
6454 the new range is the minimum of the two ranges. If they
6455 cannot be compared, then give up. */
6456 cmp = compare_values (vr0->min, vr1->min);
6457 if (cmp == 0 || cmp == 1)
6464 /* Similarly, the upper limit of the new range is the maximum
6465 of the two ranges. If they cannot be compared, then
6467 cmp = compare_values (vr0->max, vr1->max);
6468 if (cmp == 0 || cmp == -1)
6475 /* Check for useless ranges. */
6476 if (INTEGRAL_TYPE_P (TREE_TYPE (min))
6477 && ((vrp_val_is_min (min) || is_overflow_infinity (min))
6478 && (vrp_val_is_max (max) || is_overflow_infinity (max))))
6481 /* The resulting set of equivalences is the intersection of
6483 if (vr0->equiv && vr1->equiv && vr0->equiv != vr1->equiv)
6484 bitmap_and_into (vr0->equiv, vr1->equiv);
6485 else if (vr0->equiv && !vr1->equiv)
6486 bitmap_clear (vr0->equiv);
6488 set_value_range (vr0, vr0->type, min, max, vr0->equiv);
6490 else if (vr0->type == VR_ANTI_RANGE && vr1->type == VR_ANTI_RANGE)
6492 /* Two anti-ranges meet only if their complements intersect.
6493 Only handle the case of identical ranges. */
6494 if (compare_values (vr0->min, vr1->min) == 0
6495 && compare_values (vr0->max, vr1->max) == 0
6496 && compare_values (vr0->min, vr0->max) == 0)
6498 /* The resulting set of equivalences is the intersection of
6500 if (vr0->equiv && vr1->equiv && vr0->equiv != vr1->equiv)
6501 bitmap_and_into (vr0->equiv, vr1->equiv);
6502 else if (vr0->equiv && !vr1->equiv)
6503 bitmap_clear (vr0->equiv);
6508 else if (vr0->type == VR_ANTI_RANGE || vr1->type == VR_ANTI_RANGE)
6510 /* For a numeric range [VAL1, VAL2] and an anti-range ~[VAL3, VAL4],
6511 only handle the case where the ranges have an empty intersection.
6512 The result of the meet operation is the anti-range. */
6513 if (!symbolic_range_p (vr0)
6514 && !symbolic_range_p (vr1)
6515 && !value_ranges_intersect_p (vr0, vr1))
6517 /* Copy most of VR1 into VR0. Don't copy VR1's equivalence
6518 set. We need to compute the intersection of the two
6519 equivalence sets. */
6520 if (vr1->type == VR_ANTI_RANGE)
6521 set_value_range (vr0, vr1->type, vr1->min, vr1->max, vr0->equiv);
6523 /* The resulting set of equivalences is the intersection of
6525 if (vr0->equiv && vr1->equiv && vr0->equiv != vr1->equiv)
6526 bitmap_and_into (vr0->equiv, vr1->equiv);
6527 else if (vr0->equiv && !vr1->equiv)
6528 bitmap_clear (vr0->equiv);
6539 /* Failed to find an efficient meet. Before giving up and setting
6540 the result to VARYING, see if we can at least derive a useful
6541 anti-range. FIXME, all this nonsense about distinguishing
6542 anti-ranges from ranges is necessary because of the odd
6543 semantics of range_includes_zero_p and friends. */
6544 if (!symbolic_range_p (vr0)
6545 && ((vr0->type == VR_RANGE
6546 && range_includes_zero_p (vr0->min, vr0->max) == 0)
6547 || (vr0->type == VR_ANTI_RANGE
6548 && range_includes_zero_p (vr0->min, vr0->max) == 1))
6549 && !symbolic_range_p (vr1)
6550 && ((vr1->type == VR_RANGE
6551 && range_includes_zero_p (vr1->min, vr1->max) == 0)
6552 || (vr1->type == VR_ANTI_RANGE
6553 && range_includes_zero_p (vr1->min, vr1->max) == 1)))
6555 set_value_range_to_nonnull (vr0, TREE_TYPE (vr0->min));
6557 /* Since this meet operation did not result from the meeting of
6558 two equivalent names, VR0 cannot have any equivalences. */
6560 bitmap_clear (vr0->equiv);
6563 set_value_range_to_varying (vr0);
6567 /* Visit all arguments for PHI node PHI that flow through executable
6568 edges. If a valid value range can be derived from all the incoming
6569 value ranges, set a new range for the LHS of PHI. */
6571 static enum ssa_prop_result
6572 vrp_visit_phi_node (gimple phi)
6575 tree lhs = PHI_RESULT (phi);
6576 value_range_t *lhs_vr = get_value_range (lhs);
6577 value_range_t vr_result = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
6579 int edges, old_edges;
6582 if (dump_file && (dump_flags & TDF_DETAILS))
6584 fprintf (dump_file, "\nVisiting PHI node: ");
6585 print_gimple_stmt (dump_file, phi, 0, dump_flags);
6589 for (i = 0; i < gimple_phi_num_args (phi); i++)
6591 edge e = gimple_phi_arg_edge (phi, i);
6593 if (dump_file && (dump_flags & TDF_DETAILS))
6596 "\n Argument #%d (%d -> %d %sexecutable)\n",
6597 (int) i, e->src->index, e->dest->index,
6598 (e->flags & EDGE_EXECUTABLE) ? "" : "not ");
6601 if (e->flags & EDGE_EXECUTABLE)
6603 tree arg = PHI_ARG_DEF (phi, i);
6604 value_range_t vr_arg;
6608 if (TREE_CODE (arg) == SSA_NAME)
6610 vr_arg = *(get_value_range (arg));
6614 if (is_overflow_infinity (arg))
6616 arg = copy_node (arg);
6617 TREE_OVERFLOW (arg) = 0;
6620 vr_arg.type = VR_RANGE;
6623 vr_arg.equiv = NULL;
6626 if (dump_file && (dump_flags & TDF_DETAILS))
6628 fprintf (dump_file, "\t");
6629 print_generic_expr (dump_file, arg, dump_flags);
6630 fprintf (dump_file, "\n\tValue: ");
6631 dump_value_range (dump_file, &vr_arg);
6632 fprintf (dump_file, "\n");
6636 copy_value_range (&vr_result, &vr_arg);
6638 vrp_meet (&vr_result, &vr_arg);
6641 if (vr_result.type == VR_VARYING)
6646 if (vr_result.type == VR_VARYING)
6648 else if (vr_result.type == VR_UNDEFINED)
6651 old_edges = vr_phi_edge_counts[SSA_NAME_VERSION (lhs)];
6652 vr_phi_edge_counts[SSA_NAME_VERSION (lhs)] = edges;
6654 /* To prevent infinite iterations in the algorithm, derive ranges
6655 when the new value is slightly bigger or smaller than the
6656 previous one. We don't do this if we have seen a new executable
6657 edge; this helps us avoid an overflow infinity for conditionals
6658 which are not in a loop. */
6660 && gimple_phi_num_args (phi) > 1
6661 && edges == old_edges)
6663 int cmp_min = compare_values (lhs_vr->min, vr_result.min);
6664 int cmp_max = compare_values (lhs_vr->max, vr_result.max);
6666 /* For non VR_RANGE or for pointers fall back to varying if
6667 the range changed. */
6668 if ((lhs_vr->type != VR_RANGE || vr_result.type != VR_RANGE
6669 || POINTER_TYPE_P (TREE_TYPE (lhs)))
6670 && (cmp_min != 0 || cmp_max != 0))
6673 /* If the new minimum is smaller or larger than the previous
6674 one, go all the way to -INF. In the first case, to avoid
6675 iterating millions of times to reach -INF, and in the
6676 other case to avoid infinite bouncing between different
6678 if (cmp_min > 0 || cmp_min < 0)
6680 if (!needs_overflow_infinity (TREE_TYPE (vr_result.min))
6681 || !vrp_var_may_overflow (lhs, phi))
6682 vr_result.min = TYPE_MIN_VALUE (TREE_TYPE (vr_result.min));
6683 else if (supports_overflow_infinity (TREE_TYPE (vr_result.min)))
6685 negative_overflow_infinity (TREE_TYPE (vr_result.min));
6688 /* Similarly, if the new maximum is smaller or larger than
6689 the previous one, go all the way to +INF. */
6690 if (cmp_max < 0 || cmp_max > 0)
6692 if (!needs_overflow_infinity (TREE_TYPE (vr_result.max))
6693 || !vrp_var_may_overflow (lhs, phi))
6694 vr_result.max = TYPE_MAX_VALUE (TREE_TYPE (vr_result.max));
6695 else if (supports_overflow_infinity (TREE_TYPE (vr_result.max)))
6697 positive_overflow_infinity (TREE_TYPE (vr_result.max));
6700 /* If we dropped either bound to +-INF then if this is a loop
6701 PHI node SCEV may known more about its value-range. */
6702 if ((cmp_min > 0 || cmp_min < 0
6703 || cmp_max < 0 || cmp_max > 0)
6705 && (l = loop_containing_stmt (phi))
6706 && l->header == gimple_bb (phi))
6707 adjust_range_with_scev (&vr_result, l, phi, lhs);
6709 /* If we will end up with a (-INF, +INF) range, set it to
6710 VARYING. Same if the previous max value was invalid for
6711 the type and we end up with vr_result.min > vr_result.max. */
6712 if ((vrp_val_is_max (vr_result.max)
6713 && vrp_val_is_min (vr_result.min))
6714 || compare_values (vr_result.min,
6719 /* If the new range is different than the previous value, keep
6722 if (update_value_range (lhs, &vr_result))
6724 if (dump_file && (dump_flags & TDF_DETAILS))
6726 fprintf (dump_file, "Found new range for ");
6727 print_generic_expr (dump_file, lhs, 0);
6728 fprintf (dump_file, ": ");
6729 dump_value_range (dump_file, &vr_result);
6730 fprintf (dump_file, "\n\n");
6733 return SSA_PROP_INTERESTING;
6736 /* Nothing changed, don't add outgoing edges. */
6737 return SSA_PROP_NOT_INTERESTING;
6739 /* No match found. Set the LHS to VARYING. */
6741 set_value_range_to_varying (lhs_vr);
6742 return SSA_PROP_VARYING;
6745 /* Simplify boolean operations if the source is known
6746 to be already a boolean. */
6748 simplify_truth_ops_using_ranges (gimple_stmt_iterator *gsi, gimple stmt)
6750 enum tree_code rhs_code = gimple_assign_rhs_code (stmt);
6752 bool need_conversion;
6754 /* We handle only !=/== case here. */
6755 gcc_assert (rhs_code == EQ_EXPR || rhs_code == NE_EXPR);
6757 op0 = gimple_assign_rhs1 (stmt);
6758 if (!op_with_boolean_value_range_p (op0))
6761 op1 = gimple_assign_rhs2 (stmt);
6762 if (!op_with_boolean_value_range_p (op1))
6765 /* Reduce number of cases to handle to NE_EXPR. As there is no
6766 BIT_XNOR_EXPR we cannot replace A == B with a single statement. */
6767 if (rhs_code == EQ_EXPR)
6769 if (TREE_CODE (op1) == INTEGER_CST)
6770 op1 = int_const_binop (BIT_XOR_EXPR, op1, integer_one_node);
6775 lhs = gimple_assign_lhs (stmt);
6777 = !useless_type_conversion_p (TREE_TYPE (lhs), TREE_TYPE (op0));
6779 /* Make sure to not sign-extend a 1-bit 1 when converting the result. */
6781 && !TYPE_UNSIGNED (TREE_TYPE (op0))
6782 && TYPE_PRECISION (TREE_TYPE (op0)) == 1
6783 && TYPE_PRECISION (TREE_TYPE (lhs)) > 1)
6786 /* For A != 0 we can substitute A itself. */
6787 if (integer_zerop (op1))
6788 gimple_assign_set_rhs_with_ops (gsi,
6790 ? NOP_EXPR : TREE_CODE (op0),
6792 /* For A != B we substitute A ^ B. Either with conversion. */
6793 else if (need_conversion)
6796 tree tem = create_tmp_reg (TREE_TYPE (op0), NULL);
6797 newop = gimple_build_assign_with_ops (BIT_XOR_EXPR, tem, op0, op1);
6798 tem = make_ssa_name (tem, newop);
6799 gimple_assign_set_lhs (newop, tem);
6800 gsi_insert_before (gsi, newop, GSI_SAME_STMT);
6801 update_stmt (newop);
6802 gimple_assign_set_rhs_with_ops (gsi, NOP_EXPR, tem, NULL_TREE);
6806 gimple_assign_set_rhs_with_ops (gsi, BIT_XOR_EXPR, op0, op1);
6807 update_stmt (gsi_stmt (*gsi));
6812 /* Simplify a division or modulo operator to a right shift or
6813 bitwise and if the first operand is unsigned or is greater
6814 than zero and the second operand is an exact power of two. */
6817 simplify_div_or_mod_using_ranges (gimple stmt)
6819 enum tree_code rhs_code = gimple_assign_rhs_code (stmt);
6821 tree op0 = gimple_assign_rhs1 (stmt);
6822 tree op1 = gimple_assign_rhs2 (stmt);
6823 value_range_t *vr = get_value_range (gimple_assign_rhs1 (stmt));
6825 if (TYPE_UNSIGNED (TREE_TYPE (op0)))
6827 val = integer_one_node;
6833 val = compare_range_with_value (GE_EXPR, vr, integer_zero_node, &sop);
6837 && integer_onep (val)
6838 && issue_strict_overflow_warning (WARN_STRICT_OVERFLOW_MISC))
6840 location_t location;
6842 if (!gimple_has_location (stmt))
6843 location = input_location;
6845 location = gimple_location (stmt);
6846 warning_at (location, OPT_Wstrict_overflow,
6847 "assuming signed overflow does not occur when "
6848 "simplifying %</%> or %<%%%> to %<>>%> or %<&%>");
6852 if (val && integer_onep (val))
6856 if (rhs_code == TRUNC_DIV_EXPR)
6858 t = build_int_cst (integer_type_node, tree_log2 (op1));
6859 gimple_assign_set_rhs_code (stmt, RSHIFT_EXPR);
6860 gimple_assign_set_rhs1 (stmt, op0);
6861 gimple_assign_set_rhs2 (stmt, t);
6865 t = build_int_cst (TREE_TYPE (op1), 1);
6866 t = int_const_binop (MINUS_EXPR, op1, t);
6867 t = fold_convert (TREE_TYPE (op0), t);
6869 gimple_assign_set_rhs_code (stmt, BIT_AND_EXPR);
6870 gimple_assign_set_rhs1 (stmt, op0);
6871 gimple_assign_set_rhs2 (stmt, t);
6881 /* If the operand to an ABS_EXPR is >= 0, then eliminate the
6882 ABS_EXPR. If the operand is <= 0, then simplify the
6883 ABS_EXPR into a NEGATE_EXPR. */
6886 simplify_abs_using_ranges (gimple stmt)
6889 tree op = gimple_assign_rhs1 (stmt);
6890 tree type = TREE_TYPE (op);
6891 value_range_t *vr = get_value_range (op);
6893 if (TYPE_UNSIGNED (type))
6895 val = integer_zero_node;
6901 val = compare_range_with_value (LE_EXPR, vr, integer_zero_node, &sop);
6905 val = compare_range_with_value (GE_EXPR, vr, integer_zero_node,
6910 if (integer_zerop (val))
6911 val = integer_one_node;
6912 else if (integer_onep (val))
6913 val = integer_zero_node;
6918 && (integer_onep (val) || integer_zerop (val)))
6920 if (sop && issue_strict_overflow_warning (WARN_STRICT_OVERFLOW_MISC))
6922 location_t location;
6924 if (!gimple_has_location (stmt))
6925 location = input_location;
6927 location = gimple_location (stmt);
6928 warning_at (location, OPT_Wstrict_overflow,
6929 "assuming signed overflow does not occur when "
6930 "simplifying %<abs (X)%> to %<X%> or %<-X%>");
6933 gimple_assign_set_rhs1 (stmt, op);
6934 if (integer_onep (val))
6935 gimple_assign_set_rhs_code (stmt, NEGATE_EXPR);
6937 gimple_assign_set_rhs_code (stmt, SSA_NAME);
6946 /* Optimize away redundant BIT_AND_EXPR and BIT_IOR_EXPR.
6947 If all the bits that are being cleared by & are already
6948 known to be zero from VR, or all the bits that are being
6949 set by | are already known to be one from VR, the bit
6950 operation is redundant. */
6953 simplify_bit_ops_using_ranges (gimple_stmt_iterator *gsi, gimple stmt)
6955 tree op0 = gimple_assign_rhs1 (stmt);
6956 tree op1 = gimple_assign_rhs2 (stmt);
6957 tree op = NULL_TREE;
6958 value_range_t vr0 = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
6959 value_range_t vr1 = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
6960 double_int may_be_nonzero0, may_be_nonzero1;
6961 double_int must_be_nonzero0, must_be_nonzero1;
6964 if (TREE_CODE (op0) == SSA_NAME)
6965 vr0 = *(get_value_range (op0));
6966 else if (is_gimple_min_invariant (op0))
6967 set_value_range_to_value (&vr0, op0, NULL);
6971 if (TREE_CODE (op1) == SSA_NAME)
6972 vr1 = *(get_value_range (op1));
6973 else if (is_gimple_min_invariant (op1))
6974 set_value_range_to_value (&vr1, op1, NULL);
6978 if (!zero_nonzero_bits_from_vr (&vr0, &may_be_nonzero0, &must_be_nonzero0))
6980 if (!zero_nonzero_bits_from_vr (&vr1, &may_be_nonzero1, &must_be_nonzero1))
6983 switch (gimple_assign_rhs_code (stmt))
6986 mask = double_int_and_not (may_be_nonzero0, must_be_nonzero1);
6987 if (double_int_zero_p (mask))
6992 mask = double_int_and_not (may_be_nonzero1, must_be_nonzero0);
6993 if (double_int_zero_p (mask))
7000 mask = double_int_and_not (may_be_nonzero0, must_be_nonzero1);
7001 if (double_int_zero_p (mask))
7006 mask = double_int_and_not (may_be_nonzero1, must_be_nonzero0);
7007 if (double_int_zero_p (mask))
7017 if (op == NULL_TREE)
7020 gimple_assign_set_rhs_with_ops (gsi, TREE_CODE (op), op, NULL);
7021 update_stmt (gsi_stmt (*gsi));
7025 /* We are comparing trees OP0 and OP1 using COND_CODE. OP0 has
7026 a known value range VR.
7028 If there is one and only one value which will satisfy the
7029 conditional, then return that value. Else return NULL. */
7032 test_for_singularity (enum tree_code cond_code, tree op0,
7033 tree op1, value_range_t *vr)
7038 /* Extract minimum/maximum values which satisfy the
7039 the conditional as it was written. */
7040 if (cond_code == LE_EXPR || cond_code == LT_EXPR)
7042 /* This should not be negative infinity; there is no overflow
7044 min = TYPE_MIN_VALUE (TREE_TYPE (op0));
7047 if (cond_code == LT_EXPR && !is_overflow_infinity (max))
7049 tree one = build_int_cst (TREE_TYPE (op0), 1);
7050 max = fold_build2 (MINUS_EXPR, TREE_TYPE (op0), max, one);
7052 TREE_NO_WARNING (max) = 1;
7055 else if (cond_code == GE_EXPR || cond_code == GT_EXPR)
7057 /* This should not be positive infinity; there is no overflow
7059 max = TYPE_MAX_VALUE (TREE_TYPE (op0));
7062 if (cond_code == GT_EXPR && !is_overflow_infinity (min))
7064 tree one = build_int_cst (TREE_TYPE (op0), 1);
7065 min = fold_build2 (PLUS_EXPR, TREE_TYPE (op0), min, one);
7067 TREE_NO_WARNING (min) = 1;
7071 /* Now refine the minimum and maximum values using any
7072 value range information we have for op0. */
7075 if (compare_values (vr->min, min) == 1)
7077 if (compare_values (vr->max, max) == -1)
7080 /* If the new min/max values have converged to a single value,
7081 then there is only one value which can satisfy the condition,
7082 return that value. */
7083 if (operand_equal_p (min, max, 0) && is_gimple_min_invariant (min))
7089 /* Simplify a conditional using a relational operator to an equality
7090 test if the range information indicates only one value can satisfy
7091 the original conditional. */
7094 simplify_cond_using_ranges (gimple stmt)
7096 tree op0 = gimple_cond_lhs (stmt);
7097 tree op1 = gimple_cond_rhs (stmt);
7098 enum tree_code cond_code = gimple_cond_code (stmt);
7100 if (cond_code != NE_EXPR
7101 && cond_code != EQ_EXPR
7102 && TREE_CODE (op0) == SSA_NAME
7103 && INTEGRAL_TYPE_P (TREE_TYPE (op0))
7104 && is_gimple_min_invariant (op1))
7106 value_range_t *vr = get_value_range (op0);
7108 /* If we have range information for OP0, then we might be
7109 able to simplify this conditional. */
7110 if (vr->type == VR_RANGE)
7112 tree new_tree = test_for_singularity (cond_code, op0, op1, vr);
7118 fprintf (dump_file, "Simplified relational ");
7119 print_gimple_stmt (dump_file, stmt, 0, 0);
7120 fprintf (dump_file, " into ");
7123 gimple_cond_set_code (stmt, EQ_EXPR);
7124 gimple_cond_set_lhs (stmt, op0);
7125 gimple_cond_set_rhs (stmt, new_tree);
7131 print_gimple_stmt (dump_file, stmt, 0, 0);
7132 fprintf (dump_file, "\n");
7138 /* Try again after inverting the condition. We only deal
7139 with integral types here, so no need to worry about
7140 issues with inverting FP comparisons. */
7141 cond_code = invert_tree_comparison (cond_code, false);
7142 new_tree = test_for_singularity (cond_code, op0, op1, vr);
7148 fprintf (dump_file, "Simplified relational ");
7149 print_gimple_stmt (dump_file, stmt, 0, 0);
7150 fprintf (dump_file, " into ");
7153 gimple_cond_set_code (stmt, NE_EXPR);
7154 gimple_cond_set_lhs (stmt, op0);
7155 gimple_cond_set_rhs (stmt, new_tree);
7161 print_gimple_stmt (dump_file, stmt, 0, 0);
7162 fprintf (dump_file, "\n");
7173 /* Simplify a switch statement using the value range of the switch
7177 simplify_switch_using_ranges (gimple stmt)
7179 tree op = gimple_switch_index (stmt);
7184 size_t i = 0, j = 0, n, n2;
7188 if (TREE_CODE (op) == SSA_NAME)
7190 vr = get_value_range (op);
7192 /* We can only handle integer ranges. */
7193 if (vr->type != VR_RANGE
7194 || symbolic_range_p (vr))
7197 /* Find case label for min/max of the value range. */
7198 take_default = !find_case_label_range (stmt, vr->min, vr->max, &i, &j);
7200 else if (TREE_CODE (op) == INTEGER_CST)
7202 take_default = !find_case_label_index (stmt, 1, op, &i);
7216 n = gimple_switch_num_labels (stmt);
7218 /* Bail out if this is just all edges taken. */
7224 /* Build a new vector of taken case labels. */
7225 vec2 = make_tree_vec (j - i + 1 + (int)take_default);
7228 /* Add the default edge, if necessary. */
7230 TREE_VEC_ELT (vec2, n2++) = gimple_switch_default_label (stmt);
7232 for (; i <= j; ++i, ++n2)
7233 TREE_VEC_ELT (vec2, n2) = gimple_switch_label (stmt, i);
7235 /* Mark needed edges. */
7236 for (i = 0; i < n2; ++i)
7238 e = find_edge (gimple_bb (stmt),
7239 label_to_block (CASE_LABEL (TREE_VEC_ELT (vec2, i))));
7240 e->aux = (void *)-1;
7243 /* Queue not needed edges for later removal. */
7244 FOR_EACH_EDGE (e, ei, gimple_bb (stmt)->succs)
7246 if (e->aux == (void *)-1)
7252 if (dump_file && (dump_flags & TDF_DETAILS))
7254 fprintf (dump_file, "removing unreachable case label\n");
7256 VEC_safe_push (edge, heap, to_remove_edges, e);
7257 e->flags &= ~EDGE_EXECUTABLE;
7260 /* And queue an update for the stmt. */
7263 VEC_safe_push (switch_update, heap, to_update_switch_stmts, &su);
7267 /* Simplify an integral conversion from an SSA name in STMT. */
7270 simplify_conversion_using_ranges (gimple stmt)
7272 tree innerop, middleop, finaltype;
7274 value_range_t *innervr;
7275 bool inner_unsigned_p, middle_unsigned_p, final_unsigned_p;
7276 unsigned inner_prec, middle_prec, final_prec;
7277 double_int innermin, innermed, innermax, middlemin, middlemed, middlemax;
7279 finaltype = TREE_TYPE (gimple_assign_lhs (stmt));
7280 if (!INTEGRAL_TYPE_P (finaltype))
7282 middleop = gimple_assign_rhs1 (stmt);
7283 def_stmt = SSA_NAME_DEF_STMT (middleop);
7284 if (!is_gimple_assign (def_stmt)
7285 || !CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (def_stmt)))
7287 innerop = gimple_assign_rhs1 (def_stmt);
7288 if (TREE_CODE (innerop) != SSA_NAME)
7291 /* Get the value-range of the inner operand. */
7292 innervr = get_value_range (innerop);
7293 if (innervr->type != VR_RANGE
7294 || TREE_CODE (innervr->min) != INTEGER_CST
7295 || TREE_CODE (innervr->max) != INTEGER_CST)
7298 /* Simulate the conversion chain to check if the result is equal if
7299 the middle conversion is removed. */
7300 innermin = tree_to_double_int (innervr->min);
7301 innermax = tree_to_double_int (innervr->max);
7303 inner_prec = TYPE_PRECISION (TREE_TYPE (innerop));
7304 middle_prec = TYPE_PRECISION (TREE_TYPE (middleop));
7305 final_prec = TYPE_PRECISION (finaltype);
7307 /* If the first conversion is not injective, the second must not
7309 if (double_int_cmp (double_int_sub (innermax, innermin),
7310 double_int_mask (middle_prec), true) > 0
7311 && middle_prec < final_prec)
7313 /* We also want a medium value so that we can track the effect that
7314 narrowing conversions with sign change have. */
7315 inner_unsigned_p = TYPE_UNSIGNED (TREE_TYPE (innerop));
7316 if (inner_unsigned_p)
7317 innermed = double_int_rshift (double_int_mask (inner_prec),
7318 1, inner_prec, false);
7320 innermed = double_int_zero;
7321 if (double_int_cmp (innermin, innermed, inner_unsigned_p) >= 0
7322 || double_int_cmp (innermed, innermax, inner_unsigned_p) >= 0)
7323 innermed = innermin;
7325 middle_unsigned_p = TYPE_UNSIGNED (TREE_TYPE (middleop));
7326 middlemin = double_int_ext (innermin, middle_prec, middle_unsigned_p);
7327 middlemed = double_int_ext (innermed, middle_prec, middle_unsigned_p);
7328 middlemax = double_int_ext (innermax, middle_prec, middle_unsigned_p);
7330 /* Require that the final conversion applied to both the original
7331 and the intermediate range produces the same result. */
7332 final_unsigned_p = TYPE_UNSIGNED (finaltype);
7333 if (!double_int_equal_p (double_int_ext (middlemin,
7334 final_prec, final_unsigned_p),
7335 double_int_ext (innermin,
7336 final_prec, final_unsigned_p))
7337 || !double_int_equal_p (double_int_ext (middlemed,
7338 final_prec, final_unsigned_p),
7339 double_int_ext (innermed,
7340 final_prec, final_unsigned_p))
7341 || !double_int_equal_p (double_int_ext (middlemax,
7342 final_prec, final_unsigned_p),
7343 double_int_ext (innermax,
7344 final_prec, final_unsigned_p)))
7347 gimple_assign_set_rhs1 (stmt, innerop);
7352 /* Return whether the value range *VR fits in an integer type specified
7353 by PRECISION and UNSIGNED_P. */
7356 range_fits_type_p (value_range_t *vr, unsigned precision, bool unsigned_p)
7359 unsigned src_precision;
7362 /* We can only handle integral and pointer types. */
7363 src_type = TREE_TYPE (vr->min);
7364 if (!INTEGRAL_TYPE_P (src_type)
7365 && !POINTER_TYPE_P (src_type))
7368 /* An extension is always fine, so is an identity transform. */
7369 src_precision = TYPE_PRECISION (TREE_TYPE (vr->min));
7370 if (src_precision < precision
7371 || (src_precision == precision
7372 && TYPE_UNSIGNED (src_type) == unsigned_p))
7375 /* Now we can only handle ranges with constant bounds. */
7376 if (vr->type != VR_RANGE
7377 || TREE_CODE (vr->min) != INTEGER_CST
7378 || TREE_CODE (vr->max) != INTEGER_CST)
7381 /* For precision-preserving sign-changes the MSB of the double-int
7383 if (src_precision == precision
7384 && (TREE_INT_CST_HIGH (vr->min) | TREE_INT_CST_HIGH (vr->max)) < 0)
7387 /* Then we can perform the conversion on both ends and compare
7388 the result for equality. */
7389 tem = double_int_ext (tree_to_double_int (vr->min), precision, unsigned_p);
7390 if (!double_int_equal_p (tree_to_double_int (vr->min), tem))
7392 tem = double_int_ext (tree_to_double_int (vr->max), precision, unsigned_p);
7393 if (!double_int_equal_p (tree_to_double_int (vr->max), tem))
7399 /* Simplify a conversion from integral SSA name to float in STMT. */
7402 simplify_float_conversion_using_ranges (gimple_stmt_iterator *gsi, gimple stmt)
7404 tree rhs1 = gimple_assign_rhs1 (stmt);
7405 value_range_t *vr = get_value_range (rhs1);
7406 enum machine_mode fltmode = TYPE_MODE (TREE_TYPE (gimple_assign_lhs (stmt)));
7407 enum machine_mode mode;
7411 /* We can only handle constant ranges. */
7412 if (vr->type != VR_RANGE
7413 || TREE_CODE (vr->min) != INTEGER_CST
7414 || TREE_CODE (vr->max) != INTEGER_CST)
7417 /* First check if we can use a signed type in place of an unsigned. */
7418 if (TYPE_UNSIGNED (TREE_TYPE (rhs1))
7419 && (can_float_p (fltmode, TYPE_MODE (TREE_TYPE (rhs1)), 0)
7420 != CODE_FOR_nothing)
7421 && range_fits_type_p (vr, GET_MODE_PRECISION
7422 (TYPE_MODE (TREE_TYPE (rhs1))), 0))
7423 mode = TYPE_MODE (TREE_TYPE (rhs1));
7424 /* If we can do the conversion in the current input mode do nothing. */
7425 else if (can_float_p (fltmode, TYPE_MODE (TREE_TYPE (rhs1)),
7426 TYPE_UNSIGNED (TREE_TYPE (rhs1))))
7428 /* Otherwise search for a mode we can use, starting from the narrowest
7429 integer mode available. */
7432 mode = GET_CLASS_NARROWEST_MODE (MODE_INT);
7435 /* If we cannot do a signed conversion to float from mode
7436 or if the value-range does not fit in the signed type
7437 try with a wider mode. */
7438 if (can_float_p (fltmode, mode, 0) != CODE_FOR_nothing
7439 && range_fits_type_p (vr, GET_MODE_PRECISION (mode), 0))
7442 mode = GET_MODE_WIDER_MODE (mode);
7443 /* But do not widen the input. Instead leave that to the
7444 optabs expansion code. */
7445 if (GET_MODE_PRECISION (mode) > TYPE_PRECISION (TREE_TYPE (rhs1)))
7448 while (mode != VOIDmode);
7449 if (mode == VOIDmode)
7453 /* It works, insert a truncation or sign-change before the
7454 float conversion. */
7455 tem = create_tmp_var (build_nonstandard_integer_type
7456 (GET_MODE_PRECISION (mode), 0), NULL);
7457 conv = gimple_build_assign_with_ops (NOP_EXPR, tem, rhs1, NULL_TREE);
7458 tem = make_ssa_name (tem, conv);
7459 gimple_assign_set_lhs (conv, tem);
7460 gsi_insert_before (gsi, conv, GSI_SAME_STMT);
7461 gimple_assign_set_rhs1 (stmt, tem);
7467 /* Simplify STMT using ranges if possible. */
7470 simplify_stmt_using_ranges (gimple_stmt_iterator *gsi)
7472 gimple stmt = gsi_stmt (*gsi);
7473 if (is_gimple_assign (stmt))
7475 enum tree_code rhs_code = gimple_assign_rhs_code (stmt);
7476 tree rhs1 = gimple_assign_rhs1 (stmt);
7482 /* Transform EQ_EXPR, NE_EXPR into BIT_XOR_EXPR or identity
7483 if the RHS is zero or one, and the LHS are known to be boolean
7485 if (INTEGRAL_TYPE_P (TREE_TYPE (rhs1)))
7486 return simplify_truth_ops_using_ranges (gsi, stmt);
7489 /* Transform TRUNC_DIV_EXPR and TRUNC_MOD_EXPR into RSHIFT_EXPR
7490 and BIT_AND_EXPR respectively if the first operand is greater
7491 than zero and the second operand is an exact power of two. */
7492 case TRUNC_DIV_EXPR:
7493 case TRUNC_MOD_EXPR:
7494 if (INTEGRAL_TYPE_P (TREE_TYPE (rhs1))
7495 && integer_pow2p (gimple_assign_rhs2 (stmt)))
7496 return simplify_div_or_mod_using_ranges (stmt);
7499 /* Transform ABS (X) into X or -X as appropriate. */
7501 if (TREE_CODE (rhs1) == SSA_NAME
7502 && INTEGRAL_TYPE_P (TREE_TYPE (rhs1)))
7503 return simplify_abs_using_ranges (stmt);
7508 /* Optimize away BIT_AND_EXPR and BIT_IOR_EXPR
7509 if all the bits being cleared are already cleared or
7510 all the bits being set are already set. */
7511 if (INTEGRAL_TYPE_P (TREE_TYPE (rhs1)))
7512 return simplify_bit_ops_using_ranges (gsi, stmt);
7516 if (TREE_CODE (rhs1) == SSA_NAME
7517 && INTEGRAL_TYPE_P (TREE_TYPE (rhs1)))
7518 return simplify_conversion_using_ranges (stmt);
7522 if (TREE_CODE (rhs1) == SSA_NAME
7523 && INTEGRAL_TYPE_P (TREE_TYPE (rhs1)))
7524 return simplify_float_conversion_using_ranges (gsi, stmt);
7531 else if (gimple_code (stmt) == GIMPLE_COND)
7532 return simplify_cond_using_ranges (stmt);
7533 else if (gimple_code (stmt) == GIMPLE_SWITCH)
7534 return simplify_switch_using_ranges (stmt);
7539 /* If the statement pointed by SI has a predicate whose value can be
7540 computed using the value range information computed by VRP, compute
7541 its value and return true. Otherwise, return false. */
7544 fold_predicate_in (gimple_stmt_iterator *si)
7546 bool assignment_p = false;
7548 gimple stmt = gsi_stmt (*si);
7550 if (is_gimple_assign (stmt)
7551 && TREE_CODE_CLASS (gimple_assign_rhs_code (stmt)) == tcc_comparison)
7553 assignment_p = true;
7554 val = vrp_evaluate_conditional (gimple_assign_rhs_code (stmt),
7555 gimple_assign_rhs1 (stmt),
7556 gimple_assign_rhs2 (stmt),
7559 else if (gimple_code (stmt) == GIMPLE_COND)
7560 val = vrp_evaluate_conditional (gimple_cond_code (stmt),
7561 gimple_cond_lhs (stmt),
7562 gimple_cond_rhs (stmt),
7570 val = fold_convert (gimple_expr_type (stmt), val);
7574 fprintf (dump_file, "Folding predicate ");
7575 print_gimple_expr (dump_file, stmt, 0, 0);
7576 fprintf (dump_file, " to ");
7577 print_generic_expr (dump_file, val, 0);
7578 fprintf (dump_file, "\n");
7581 if (is_gimple_assign (stmt))
7582 gimple_assign_set_rhs_from_tree (si, val);
7585 gcc_assert (gimple_code (stmt) == GIMPLE_COND);
7586 if (integer_zerop (val))
7587 gimple_cond_make_false (stmt);
7588 else if (integer_onep (val))
7589 gimple_cond_make_true (stmt);
7600 /* Callback for substitute_and_fold folding the stmt at *SI. */
7603 vrp_fold_stmt (gimple_stmt_iterator *si)
7605 if (fold_predicate_in (si))
7608 return simplify_stmt_using_ranges (si);
7611 /* Stack of dest,src equivalency pairs that need to be restored after
7612 each attempt to thread a block's incoming edge to an outgoing edge.
7614 A NULL entry is used to mark the end of pairs which need to be
7616 static VEC(tree,heap) *stack;
7618 /* A trivial wrapper so that we can present the generic jump threading
7619 code with a simple API for simplifying statements. STMT is the
7620 statement we want to simplify, WITHIN_STMT provides the location
7621 for any overflow warnings. */
7624 simplify_stmt_for_jump_threading (gimple stmt, gimple within_stmt)
7626 /* We only use VRP information to simplify conditionals. This is
7627 overly conservative, but it's unclear if doing more would be
7628 worth the compile time cost. */
7629 if (gimple_code (stmt) != GIMPLE_COND)
7632 return vrp_evaluate_conditional (gimple_cond_code (stmt),
7633 gimple_cond_lhs (stmt),
7634 gimple_cond_rhs (stmt), within_stmt);
7637 /* Blocks which have more than one predecessor and more than
7638 one successor present jump threading opportunities, i.e.,
7639 when the block is reached from a specific predecessor, we
7640 may be able to determine which of the outgoing edges will
7641 be traversed. When this optimization applies, we are able
7642 to avoid conditionals at runtime and we may expose secondary
7643 optimization opportunities.
7645 This routine is effectively a driver for the generic jump
7646 threading code. It basically just presents the generic code
7647 with edges that may be suitable for jump threading.
7649 Unlike DOM, we do not iterate VRP if jump threading was successful.
7650 While iterating may expose new opportunities for VRP, it is expected
7651 those opportunities would be very limited and the compile time cost
7652 to expose those opportunities would be significant.
7654 As jump threading opportunities are discovered, they are registered
7655 for later realization. */
7658 identify_jump_threads (void)
7665 /* Ugh. When substituting values earlier in this pass we can
7666 wipe the dominance information. So rebuild the dominator
7667 information as we need it within the jump threading code. */
7668 calculate_dominance_info (CDI_DOMINATORS);
7670 /* We do not allow VRP information to be used for jump threading
7671 across a back edge in the CFG. Otherwise it becomes too
7672 difficult to avoid eliminating loop exit tests. Of course
7673 EDGE_DFS_BACK is not accurate at this time so we have to
7675 mark_dfs_back_edges ();
7677 /* Do not thread across edges we are about to remove. Just marking
7678 them as EDGE_DFS_BACK will do. */
7679 FOR_EACH_VEC_ELT (edge, to_remove_edges, i, e)
7680 e->flags |= EDGE_DFS_BACK;
7682 /* Allocate our unwinder stack to unwind any temporary equivalences
7683 that might be recorded. */
7684 stack = VEC_alloc (tree, heap, 20);
7686 /* To avoid lots of silly node creation, we create a single
7687 conditional and just modify it in-place when attempting to
7689 dummy = gimple_build_cond (EQ_EXPR,
7690 integer_zero_node, integer_zero_node,
7693 /* Walk through all the blocks finding those which present a
7694 potential jump threading opportunity. We could set this up
7695 as a dominator walker and record data during the walk, but
7696 I doubt it's worth the effort for the classes of jump
7697 threading opportunities we are trying to identify at this
7698 point in compilation. */
7703 /* If the generic jump threading code does not find this block
7704 interesting, then there is nothing to do. */
7705 if (! potentially_threadable_block (bb))
7708 /* We only care about blocks ending in a COND_EXPR. While there
7709 may be some value in handling SWITCH_EXPR here, I doubt it's
7710 terribly important. */
7711 last = gsi_stmt (gsi_last_bb (bb));
7713 /* We're basically looking for a switch or any kind of conditional with
7714 integral or pointer type arguments. Note the type of the second
7715 argument will be the same as the first argument, so no need to
7716 check it explicitly. */
7717 if (gimple_code (last) == GIMPLE_SWITCH
7718 || (gimple_code (last) == GIMPLE_COND
7719 && TREE_CODE (gimple_cond_lhs (last)) == SSA_NAME
7720 && (INTEGRAL_TYPE_P (TREE_TYPE (gimple_cond_lhs (last)))
7721 || POINTER_TYPE_P (TREE_TYPE (gimple_cond_lhs (last))))
7722 && (TREE_CODE (gimple_cond_rhs (last)) == SSA_NAME
7723 || is_gimple_min_invariant (gimple_cond_rhs (last)))))
7727 /* We've got a block with multiple predecessors and multiple
7728 successors which also ends in a suitable conditional or
7729 switch statement. For each predecessor, see if we can thread
7730 it to a specific successor. */
7731 FOR_EACH_EDGE (e, ei, bb->preds)
7733 /* Do not thread across back edges or abnormal edges
7735 if (e->flags & (EDGE_DFS_BACK | EDGE_COMPLEX))
7738 thread_across_edge (dummy, e, true, &stack,
7739 simplify_stmt_for_jump_threading);
7744 /* We do not actually update the CFG or SSA graphs at this point as
7745 ASSERT_EXPRs are still in the IL and cfg cleanup code does not yet
7746 handle ASSERT_EXPRs gracefully. */
7749 /* We identified all the jump threading opportunities earlier, but could
7750 not transform the CFG at that time. This routine transforms the
7751 CFG and arranges for the dominator tree to be rebuilt if necessary.
7753 Note the SSA graph update will occur during the normal TODO
7754 processing by the pass manager. */
7756 finalize_jump_threads (void)
7758 thread_through_all_blocks (false);
7759 VEC_free (tree, heap, stack);
7763 /* Traverse all the blocks folding conditionals with known ranges. */
7770 values_propagated = true;
7774 fprintf (dump_file, "\nValue ranges after VRP:\n\n");
7775 dump_all_value_ranges (dump_file);
7776 fprintf (dump_file, "\n");
7779 substitute_and_fold (op_with_constant_singleton_value_range,
7780 vrp_fold_stmt, false);
7782 if (warn_array_bounds)
7783 check_all_array_refs ();
7785 /* We must identify jump threading opportunities before we release
7786 the datastructures built by VRP. */
7787 identify_jump_threads ();
7789 /* Free allocated memory. */
7790 for (i = 0; i < num_vr_values; i++)
7793 BITMAP_FREE (vr_value[i]->equiv);
7798 free (vr_phi_edge_counts);
7800 /* So that we can distinguish between VRP data being available
7801 and not available. */
7803 vr_phi_edge_counts = NULL;
7807 /* Main entry point to VRP (Value Range Propagation). This pass is
7808 loosely based on J. R. C. Patterson, ``Accurate Static Branch
7809 Prediction by Value Range Propagation,'' in SIGPLAN Conference on
7810 Programming Language Design and Implementation, pp. 67-78, 1995.
7811 Also available at http://citeseer.ist.psu.edu/patterson95accurate.html
7813 This is essentially an SSA-CCP pass modified to deal with ranges
7814 instead of constants.
7816 While propagating ranges, we may find that two or more SSA name
7817 have equivalent, though distinct ranges. For instance,
7820 2 p_4 = ASSERT_EXPR <p_3, p_3 != 0>
7822 4 p_5 = ASSERT_EXPR <p_4, p_4 == q_2>;
7826 In the code above, pointer p_5 has range [q_2, q_2], but from the
7827 code we can also determine that p_5 cannot be NULL and, if q_2 had
7828 a non-varying range, p_5's range should also be compatible with it.
7830 These equivalences are created by two expressions: ASSERT_EXPR and
7831 copy operations. Since p_5 is an assertion on p_4, and p_4 was the
7832 result of another assertion, then we can use the fact that p_5 and
7833 p_4 are equivalent when evaluating p_5's range.
7835 Together with value ranges, we also propagate these equivalences
7836 between names so that we can take advantage of information from
7837 multiple ranges when doing final replacement. Note that this
7838 equivalency relation is transitive but not symmetric.
7840 In the example above, p_5 is equivalent to p_4, q_2 and p_3, but we
7841 cannot assert that q_2 is equivalent to p_5 because q_2 may be used
7842 in contexts where that assertion does not hold (e.g., in line 6).
7844 TODO, the main difference between this pass and Patterson's is that
7845 we do not propagate edge probabilities. We only compute whether
7846 edges can be taken or not. That is, instead of having a spectrum
7847 of jump probabilities between 0 and 1, we only deal with 0, 1 and
7848 DON'T KNOW. In the future, it may be worthwhile to propagate
7849 probabilities to aid branch prediction. */
7858 loop_optimizer_init (LOOPS_NORMAL | LOOPS_HAVE_RECORDED_EXITS);
7859 rewrite_into_loop_closed_ssa (NULL, TODO_update_ssa);
7862 insert_range_assertions ();
7864 /* Estimate number of iterations - but do not use undefined behavior
7865 for this. We can't do this lazily as other functions may compute
7866 this using undefined behavior. */
7867 free_numbers_of_iterations_estimates ();
7868 estimate_numbers_of_iterations (false);
7870 to_remove_edges = VEC_alloc (edge, heap, 10);
7871 to_update_switch_stmts = VEC_alloc (switch_update, heap, 5);
7872 threadedge_initialize_values ();
7875 ssa_propagate (vrp_visit_stmt, vrp_visit_phi_node);
7878 free_numbers_of_iterations_estimates ();
7880 /* ASSERT_EXPRs must be removed before finalizing jump threads
7881 as finalizing jump threads calls the CFG cleanup code which
7882 does not properly handle ASSERT_EXPRs. */
7883 remove_range_assertions ();
7885 /* If we exposed any new variables, go ahead and put them into
7886 SSA form now, before we handle jump threading. This simplifies
7887 interactions between rewriting of _DECL nodes into SSA form
7888 and rewriting SSA_NAME nodes into SSA form after block
7889 duplication and CFG manipulation. */
7890 update_ssa (TODO_update_ssa);
7892 finalize_jump_threads ();
7894 /* Remove dead edges from SWITCH_EXPR optimization. This leaves the
7895 CFG in a broken state and requires a cfg_cleanup run. */
7896 FOR_EACH_VEC_ELT (edge, to_remove_edges, i, e)
7898 /* Update SWITCH_EXPR case label vector. */
7899 FOR_EACH_VEC_ELT (switch_update, to_update_switch_stmts, i, su)
7902 size_t n = TREE_VEC_LENGTH (su->vec);
7904 gimple_switch_set_num_labels (su->stmt, n);
7905 for (j = 0; j < n; j++)
7906 gimple_switch_set_label (su->stmt, j, TREE_VEC_ELT (su->vec, j));
7907 /* As we may have replaced the default label with a regular one
7908 make sure to make it a real default label again. This ensures
7909 optimal expansion. */
7910 label = gimple_switch_default_label (su->stmt);
7911 CASE_LOW (label) = NULL_TREE;
7912 CASE_HIGH (label) = NULL_TREE;
7915 if (VEC_length (edge, to_remove_edges) > 0)
7916 free_dominance_info (CDI_DOMINATORS);
7918 VEC_free (edge, heap, to_remove_edges);
7919 VEC_free (switch_update, heap, to_update_switch_stmts);
7920 threadedge_finalize_values ();
7923 loop_optimizer_finalize ();
7930 return flag_tree_vrp != 0;
7933 struct gimple_opt_pass pass_vrp =
7938 gate_vrp, /* gate */
7939 execute_vrp, /* execute */
7942 0, /* static_pass_number */
7943 TV_TREE_VRP, /* tv_id */
7944 PROP_ssa, /* properties_required */
7945 0, /* properties_provided */
7946 0, /* properties_destroyed */
7947 0, /* todo_flags_start */
7952 | TODO_ggc_collect /* todo_flags_finish */