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 the call is __builtin_constant_p and the argument is a
3272 function parameter resolve it to false. This avoids bogus
3273 array bound warnings.
3274 ??? We could do this as early as inlining is finished. */
3275 if (gimple_call_builtin_p (stmt, BUILT_IN_CONSTANT_P))
3277 tree arg = gimple_call_arg (stmt, 0);
3278 if (TREE_CODE (arg) == SSA_NAME
3279 && SSA_NAME_IS_DEFAULT_DEF (arg)
3280 && TREE_CODE (SSA_NAME_VAR (arg)) == PARM_DECL)
3281 set_value_range_to_null (vr, type);
3283 else if (INTEGRAL_TYPE_P (type)
3284 && gimple_stmt_nonnegative_warnv_p (stmt, &sop))
3285 set_value_range_to_nonnegative (vr, type,
3286 sop || stmt_overflow_infinity (stmt));
3287 else if (vrp_stmt_computes_nonzero (stmt, &sop)
3289 set_value_range_to_nonnull (vr, type);
3291 set_value_range_to_varying (vr);
3295 /* Try to compute a useful range out of assignment STMT and store it
3299 extract_range_from_assignment (value_range_t *vr, gimple stmt)
3301 enum tree_code code = gimple_assign_rhs_code (stmt);
3303 if (code == ASSERT_EXPR)
3304 extract_range_from_assert (vr, gimple_assign_rhs1 (stmt));
3305 else if (code == SSA_NAME)
3306 extract_range_from_ssa_name (vr, gimple_assign_rhs1 (stmt));
3307 else if (TREE_CODE_CLASS (code) == tcc_binary)
3308 extract_range_from_binary_expr (vr, gimple_assign_rhs_code (stmt),
3309 gimple_expr_type (stmt),
3310 gimple_assign_rhs1 (stmt),
3311 gimple_assign_rhs2 (stmt));
3312 else if (TREE_CODE_CLASS (code) == tcc_unary)
3313 extract_range_from_unary_expr (vr, gimple_assign_rhs_code (stmt),
3314 gimple_expr_type (stmt),
3315 gimple_assign_rhs1 (stmt));
3316 else if (code == COND_EXPR)
3317 extract_range_from_cond_expr (vr, stmt);
3318 else if (TREE_CODE_CLASS (code) == tcc_comparison)
3319 extract_range_from_comparison (vr, gimple_assign_rhs_code (stmt),
3320 gimple_expr_type (stmt),
3321 gimple_assign_rhs1 (stmt),
3322 gimple_assign_rhs2 (stmt));
3323 else if (get_gimple_rhs_class (code) == GIMPLE_SINGLE_RHS
3324 && is_gimple_min_invariant (gimple_assign_rhs1 (stmt)))
3325 set_value_range_to_value (vr, gimple_assign_rhs1 (stmt), NULL);
3327 set_value_range_to_varying (vr);
3329 if (vr->type == VR_VARYING)
3330 extract_range_basic (vr, stmt);
3333 /* Given a range VR, a LOOP and a variable VAR, determine whether it
3334 would be profitable to adjust VR using scalar evolution information
3335 for VAR. If so, update VR with the new limits. */
3338 adjust_range_with_scev (value_range_t *vr, struct loop *loop,
3339 gimple stmt, tree var)
3341 tree init, step, chrec, tmin, tmax, min, max, type, tem;
3342 enum ev_direction dir;
3344 /* TODO. Don't adjust anti-ranges. An anti-range may provide
3345 better opportunities than a regular range, but I'm not sure. */
3346 if (vr->type == VR_ANTI_RANGE)
3349 chrec = instantiate_parameters (loop, analyze_scalar_evolution (loop, var));
3351 /* Like in PR19590, scev can return a constant function. */
3352 if (is_gimple_min_invariant (chrec))
3354 set_value_range_to_value (vr, chrec, vr->equiv);
3358 if (TREE_CODE (chrec) != POLYNOMIAL_CHREC)
3361 init = initial_condition_in_loop_num (chrec, loop->num);
3362 tem = op_with_constant_singleton_value_range (init);
3365 step = evolution_part_in_loop_num (chrec, loop->num);
3366 tem = op_with_constant_singleton_value_range (step);
3370 /* If STEP is symbolic, we can't know whether INIT will be the
3371 minimum or maximum value in the range. Also, unless INIT is
3372 a simple expression, compare_values and possibly other functions
3373 in tree-vrp won't be able to handle it. */
3374 if (step == NULL_TREE
3375 || !is_gimple_min_invariant (step)
3376 || !valid_value_p (init))
3379 dir = scev_direction (chrec);
3380 if (/* Do not adjust ranges if we do not know whether the iv increases
3381 or decreases, ... */
3382 dir == EV_DIR_UNKNOWN
3383 /* ... or if it may wrap. */
3384 || scev_probably_wraps_p (init, step, stmt, get_chrec_loop (chrec),
3388 /* We use TYPE_MIN_VALUE and TYPE_MAX_VALUE here instead of
3389 negative_overflow_infinity and positive_overflow_infinity,
3390 because we have concluded that the loop probably does not
3393 type = TREE_TYPE (var);
3394 if (POINTER_TYPE_P (type) || !TYPE_MIN_VALUE (type))
3395 tmin = lower_bound_in_type (type, type);
3397 tmin = TYPE_MIN_VALUE (type);
3398 if (POINTER_TYPE_P (type) || !TYPE_MAX_VALUE (type))
3399 tmax = upper_bound_in_type (type, type);
3401 tmax = TYPE_MAX_VALUE (type);
3403 /* Try to use estimated number of iterations for the loop to constrain the
3404 final value in the evolution. */
3405 if (TREE_CODE (step) == INTEGER_CST
3406 && is_gimple_val (init)
3407 && (TREE_CODE (init) != SSA_NAME
3408 || get_value_range (init)->type == VR_RANGE))
3412 if (estimated_loop_iterations (loop, true, &nit))
3414 value_range_t maxvr = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
3416 bool unsigned_p = TYPE_UNSIGNED (TREE_TYPE (step));
3419 dtmp = double_int_mul_with_sign (tree_to_double_int (step), nit,
3420 unsigned_p, &overflow);
3421 /* If the multiplication overflowed we can't do a meaningful
3422 adjustment. Likewise if the result doesn't fit in the type
3423 of the induction variable. For a signed type we have to
3424 check whether the result has the expected signedness which
3425 is that of the step as number of iterations is unsigned. */
3427 && double_int_fits_to_tree_p (TREE_TYPE (init), dtmp)
3429 || ((dtmp.high ^ TREE_INT_CST_HIGH (step)) >= 0)))
3431 tem = double_int_to_tree (TREE_TYPE (init), dtmp);
3432 extract_range_from_binary_expr (&maxvr, PLUS_EXPR,
3433 TREE_TYPE (init), init, tem);
3434 /* Likewise if the addition did. */
3435 if (maxvr.type == VR_RANGE)
3444 if (vr->type == VR_VARYING || vr->type == VR_UNDEFINED)
3449 /* For VARYING or UNDEFINED ranges, just about anything we get
3450 from scalar evolutions should be better. */
3452 if (dir == EV_DIR_DECREASES)
3457 /* If we would create an invalid range, then just assume we
3458 know absolutely nothing. This may be over-conservative,
3459 but it's clearly safe, and should happen only in unreachable
3460 parts of code, or for invalid programs. */
3461 if (compare_values (min, max) == 1)
3464 set_value_range (vr, VR_RANGE, min, max, vr->equiv);
3466 else if (vr->type == VR_RANGE)
3471 if (dir == EV_DIR_DECREASES)
3473 /* INIT is the maximum value. If INIT is lower than VR->MAX
3474 but no smaller than VR->MIN, set VR->MAX to INIT. */
3475 if (compare_values (init, max) == -1)
3478 /* According to the loop information, the variable does not
3479 overflow. If we think it does, probably because of an
3480 overflow due to arithmetic on a different INF value,
3482 if (is_negative_overflow_infinity (min)
3483 || compare_values (min, tmin) == -1)
3489 /* If INIT is bigger than VR->MIN, set VR->MIN to INIT. */
3490 if (compare_values (init, min) == 1)
3493 if (is_positive_overflow_infinity (max)
3494 || compare_values (tmax, max) == -1)
3498 /* If we just created an invalid range with the minimum
3499 greater than the maximum, we fail conservatively.
3500 This should happen only in unreachable
3501 parts of code, or for invalid programs. */
3502 if (compare_values (min, max) == 1)
3505 set_value_range (vr, VR_RANGE, min, max, vr->equiv);
3509 /* Return true if VAR may overflow at STMT. This checks any available
3510 loop information to see if we can determine that VAR does not
3514 vrp_var_may_overflow (tree var, gimple stmt)
3517 tree chrec, init, step;
3519 if (current_loops == NULL)
3522 l = loop_containing_stmt (stmt);
3527 chrec = instantiate_parameters (l, analyze_scalar_evolution (l, var));
3528 if (TREE_CODE (chrec) != POLYNOMIAL_CHREC)
3531 init = initial_condition_in_loop_num (chrec, l->num);
3532 step = evolution_part_in_loop_num (chrec, l->num);
3534 if (step == NULL_TREE
3535 || !is_gimple_min_invariant (step)
3536 || !valid_value_p (init))
3539 /* If we get here, we know something useful about VAR based on the
3540 loop information. If it wraps, it may overflow. */
3542 if (scev_probably_wraps_p (init, step, stmt, get_chrec_loop (chrec),
3546 if (dump_file && (dump_flags & TDF_DETAILS) != 0)
3548 print_generic_expr (dump_file, var, 0);
3549 fprintf (dump_file, ": loop information indicates does not overflow\n");
3556 /* Given two numeric value ranges VR0, VR1 and a comparison code COMP:
3558 - Return BOOLEAN_TRUE_NODE if VR0 COMP VR1 always returns true for
3559 all the values in the ranges.
3561 - Return BOOLEAN_FALSE_NODE if the comparison always returns false.
3563 - Return NULL_TREE if it is not always possible to determine the
3564 value of the comparison.
3566 Also set *STRICT_OVERFLOW_P to indicate whether a range with an
3567 overflow infinity was used in the test. */
3571 compare_ranges (enum tree_code comp, value_range_t *vr0, value_range_t *vr1,
3572 bool *strict_overflow_p)
3574 /* VARYING or UNDEFINED ranges cannot be compared. */
3575 if (vr0->type == VR_VARYING
3576 || vr0->type == VR_UNDEFINED
3577 || vr1->type == VR_VARYING
3578 || vr1->type == VR_UNDEFINED)
3581 /* Anti-ranges need to be handled separately. */
3582 if (vr0->type == VR_ANTI_RANGE || vr1->type == VR_ANTI_RANGE)
3584 /* If both are anti-ranges, then we cannot compute any
3586 if (vr0->type == VR_ANTI_RANGE && vr1->type == VR_ANTI_RANGE)
3589 /* These comparisons are never statically computable. */
3596 /* Equality can be computed only between a range and an
3597 anti-range. ~[VAL1, VAL2] == [VAL1, VAL2] is always false. */
3598 if (vr0->type == VR_RANGE)
3600 /* To simplify processing, make VR0 the anti-range. */
3601 value_range_t *tmp = vr0;
3606 gcc_assert (comp == NE_EXPR || comp == EQ_EXPR);
3608 if (compare_values_warnv (vr0->min, vr1->min, strict_overflow_p) == 0
3609 && compare_values_warnv (vr0->max, vr1->max, strict_overflow_p) == 0)
3610 return (comp == NE_EXPR) ? boolean_true_node : boolean_false_node;
3615 if (!usable_range_p (vr0, strict_overflow_p)
3616 || !usable_range_p (vr1, strict_overflow_p))
3619 /* Simplify processing. If COMP is GT_EXPR or GE_EXPR, switch the
3620 operands around and change the comparison code. */
3621 if (comp == GT_EXPR || comp == GE_EXPR)
3624 comp = (comp == GT_EXPR) ? LT_EXPR : LE_EXPR;
3630 if (comp == EQ_EXPR)
3632 /* Equality may only be computed if both ranges represent
3633 exactly one value. */
3634 if (compare_values_warnv (vr0->min, vr0->max, strict_overflow_p) == 0
3635 && compare_values_warnv (vr1->min, vr1->max, strict_overflow_p) == 0)
3637 int cmp_min = compare_values_warnv (vr0->min, vr1->min,
3639 int cmp_max = compare_values_warnv (vr0->max, vr1->max,
3641 if (cmp_min == 0 && cmp_max == 0)
3642 return boolean_true_node;
3643 else if (cmp_min != -2 && cmp_max != -2)
3644 return boolean_false_node;
3646 /* If [V0_MIN, V1_MAX] < [V1_MIN, V1_MAX] then V0 != V1. */
3647 else if (compare_values_warnv (vr0->min, vr1->max,
3648 strict_overflow_p) == 1
3649 || compare_values_warnv (vr1->min, vr0->max,
3650 strict_overflow_p) == 1)
3651 return boolean_false_node;
3655 else if (comp == NE_EXPR)
3659 /* If VR0 is completely to the left or completely to the right
3660 of VR1, they are always different. Notice that we need to
3661 make sure that both comparisons yield similar results to
3662 avoid comparing values that cannot be compared at
3664 cmp1 = compare_values_warnv (vr0->max, vr1->min, strict_overflow_p);
3665 cmp2 = compare_values_warnv (vr0->min, vr1->max, strict_overflow_p);
3666 if ((cmp1 == -1 && cmp2 == -1) || (cmp1 == 1 && cmp2 == 1))
3667 return boolean_true_node;
3669 /* If VR0 and VR1 represent a single value and are identical,
3671 else if (compare_values_warnv (vr0->min, vr0->max,
3672 strict_overflow_p) == 0
3673 && compare_values_warnv (vr1->min, vr1->max,
3674 strict_overflow_p) == 0
3675 && compare_values_warnv (vr0->min, vr1->min,
3676 strict_overflow_p) == 0
3677 && compare_values_warnv (vr0->max, vr1->max,
3678 strict_overflow_p) == 0)
3679 return boolean_false_node;
3681 /* Otherwise, they may or may not be different. */
3685 else if (comp == LT_EXPR || comp == LE_EXPR)
3689 /* If VR0 is to the left of VR1, return true. */
3690 tst = compare_values_warnv (vr0->max, vr1->min, strict_overflow_p);
3691 if ((comp == LT_EXPR && tst == -1)
3692 || (comp == LE_EXPR && (tst == -1 || tst == 0)))
3694 if (overflow_infinity_range_p (vr0)
3695 || overflow_infinity_range_p (vr1))
3696 *strict_overflow_p = true;
3697 return boolean_true_node;
3700 /* If VR0 is to the right of VR1, return false. */
3701 tst = compare_values_warnv (vr0->min, vr1->max, strict_overflow_p);
3702 if ((comp == LT_EXPR && (tst == 0 || tst == 1))
3703 || (comp == LE_EXPR && tst == 1))
3705 if (overflow_infinity_range_p (vr0)
3706 || overflow_infinity_range_p (vr1))
3707 *strict_overflow_p = true;
3708 return boolean_false_node;
3711 /* Otherwise, we don't know. */
3719 /* Given a value range VR, a value VAL and a comparison code COMP, return
3720 BOOLEAN_TRUE_NODE if VR COMP VAL always returns true for all the
3721 values in VR. Return BOOLEAN_FALSE_NODE if the comparison
3722 always returns false. Return NULL_TREE if it is not always
3723 possible to determine the value of the comparison. Also set
3724 *STRICT_OVERFLOW_P to indicate whether a range with an overflow
3725 infinity was used in the test. */
3728 compare_range_with_value (enum tree_code comp, value_range_t *vr, tree val,
3729 bool *strict_overflow_p)
3731 if (vr->type == VR_VARYING || vr->type == VR_UNDEFINED)
3734 /* Anti-ranges need to be handled separately. */
3735 if (vr->type == VR_ANTI_RANGE)
3737 /* For anti-ranges, the only predicates that we can compute at
3738 compile time are equality and inequality. */
3745 /* ~[VAL_1, VAL_2] OP VAL is known if VAL_1 <= VAL <= VAL_2. */
3746 if (value_inside_range (val, vr->min, vr->max) == 1)
3747 return (comp == NE_EXPR) ? boolean_true_node : boolean_false_node;
3752 if (!usable_range_p (vr, strict_overflow_p))
3755 if (comp == EQ_EXPR)
3757 /* EQ_EXPR may only be computed if VR represents exactly
3759 if (compare_values_warnv (vr->min, vr->max, strict_overflow_p) == 0)
3761 int cmp = compare_values_warnv (vr->min, val, strict_overflow_p);
3763 return boolean_true_node;
3764 else if (cmp == -1 || cmp == 1 || cmp == 2)
3765 return boolean_false_node;
3767 else if (compare_values_warnv (val, vr->min, strict_overflow_p) == -1
3768 || compare_values_warnv (vr->max, val, strict_overflow_p) == -1)
3769 return boolean_false_node;
3773 else if (comp == NE_EXPR)
3775 /* If VAL is not inside VR, then they are always different. */
3776 if (compare_values_warnv (vr->max, val, strict_overflow_p) == -1
3777 || compare_values_warnv (vr->min, val, strict_overflow_p) == 1)
3778 return boolean_true_node;
3780 /* If VR represents exactly one value equal to VAL, then return
3782 if (compare_values_warnv (vr->min, vr->max, strict_overflow_p) == 0
3783 && compare_values_warnv (vr->min, val, strict_overflow_p) == 0)
3784 return boolean_false_node;
3786 /* Otherwise, they may or may not be different. */
3789 else if (comp == LT_EXPR || comp == LE_EXPR)
3793 /* If VR is to the left of VAL, return true. */
3794 tst = compare_values_warnv (vr->max, val, strict_overflow_p);
3795 if ((comp == LT_EXPR && tst == -1)
3796 || (comp == LE_EXPR && (tst == -1 || tst == 0)))
3798 if (overflow_infinity_range_p (vr))
3799 *strict_overflow_p = true;
3800 return boolean_true_node;
3803 /* If VR is to the right of VAL, return false. */
3804 tst = compare_values_warnv (vr->min, val, strict_overflow_p);
3805 if ((comp == LT_EXPR && (tst == 0 || tst == 1))
3806 || (comp == LE_EXPR && tst == 1))
3808 if (overflow_infinity_range_p (vr))
3809 *strict_overflow_p = true;
3810 return boolean_false_node;
3813 /* Otherwise, we don't know. */
3816 else if (comp == GT_EXPR || comp == GE_EXPR)
3820 /* If VR is to the right of VAL, return true. */
3821 tst = compare_values_warnv (vr->min, val, strict_overflow_p);
3822 if ((comp == GT_EXPR && tst == 1)
3823 || (comp == GE_EXPR && (tst == 0 || tst == 1)))
3825 if (overflow_infinity_range_p (vr))
3826 *strict_overflow_p = true;
3827 return boolean_true_node;
3830 /* If VR is to the left of VAL, return false. */
3831 tst = compare_values_warnv (vr->max, val, strict_overflow_p);
3832 if ((comp == GT_EXPR && (tst == -1 || tst == 0))
3833 || (comp == GE_EXPR && tst == -1))
3835 if (overflow_infinity_range_p (vr))
3836 *strict_overflow_p = true;
3837 return boolean_false_node;
3840 /* Otherwise, we don't know. */
3848 /* Debugging dumps. */
3850 void dump_value_range (FILE *, value_range_t *);
3851 void debug_value_range (value_range_t *);
3852 void dump_all_value_ranges (FILE *);
3853 void debug_all_value_ranges (void);
3854 void dump_vr_equiv (FILE *, bitmap);
3855 void debug_vr_equiv (bitmap);
3858 /* Dump value range VR to FILE. */
3861 dump_value_range (FILE *file, value_range_t *vr)
3864 fprintf (file, "[]");
3865 else if (vr->type == VR_UNDEFINED)
3866 fprintf (file, "UNDEFINED");
3867 else if (vr->type == VR_RANGE || vr->type == VR_ANTI_RANGE)
3869 tree type = TREE_TYPE (vr->min);
3871 fprintf (file, "%s[", (vr->type == VR_ANTI_RANGE) ? "~" : "");
3873 if (is_negative_overflow_infinity (vr->min))
3874 fprintf (file, "-INF(OVF)");
3875 else if (INTEGRAL_TYPE_P (type)
3876 && !TYPE_UNSIGNED (type)
3877 && vrp_val_is_min (vr->min))
3878 fprintf (file, "-INF");
3880 print_generic_expr (file, vr->min, 0);
3882 fprintf (file, ", ");
3884 if (is_positive_overflow_infinity (vr->max))
3885 fprintf (file, "+INF(OVF)");
3886 else if (INTEGRAL_TYPE_P (type)
3887 && vrp_val_is_max (vr->max))
3888 fprintf (file, "+INF");
3890 print_generic_expr (file, vr->max, 0);
3892 fprintf (file, "]");
3899 fprintf (file, " EQUIVALENCES: { ");
3901 EXECUTE_IF_SET_IN_BITMAP (vr->equiv, 0, i, bi)
3903 print_generic_expr (file, ssa_name (i), 0);
3904 fprintf (file, " ");
3908 fprintf (file, "} (%u elements)", c);
3911 else if (vr->type == VR_VARYING)
3912 fprintf (file, "VARYING");
3914 fprintf (file, "INVALID RANGE");
3918 /* Dump value range VR to stderr. */
3921 debug_value_range (value_range_t *vr)
3923 dump_value_range (stderr, vr);
3924 fprintf (stderr, "\n");
3928 /* Dump value ranges of all SSA_NAMEs to FILE. */
3931 dump_all_value_ranges (FILE *file)
3935 for (i = 0; i < num_vr_values; i++)
3939 print_generic_expr (file, ssa_name (i), 0);
3940 fprintf (file, ": ");
3941 dump_value_range (file, vr_value[i]);
3942 fprintf (file, "\n");
3946 fprintf (file, "\n");
3950 /* Dump all value ranges to stderr. */
3953 debug_all_value_ranges (void)
3955 dump_all_value_ranges (stderr);
3959 /* Given a COND_EXPR COND of the form 'V OP W', and an SSA name V,
3960 create a new SSA name N and return the assertion assignment
3961 'V = ASSERT_EXPR <V, V OP W>'. */
3964 build_assert_expr_for (tree cond, tree v)
3969 gcc_assert (TREE_CODE (v) == SSA_NAME);
3970 n = duplicate_ssa_name (v, NULL);
3972 if (COMPARISON_CLASS_P (cond))
3974 tree a = build2 (ASSERT_EXPR, TREE_TYPE (v), v, cond);
3975 assertion = gimple_build_assign (n, a);
3977 else if (TREE_CODE (cond) == SSA_NAME)
3979 /* Given V, build the assignment N = true. */
3980 gcc_assert (v == cond);
3981 assertion = gimple_build_assign (n, boolean_true_node);
3986 SSA_NAME_DEF_STMT (n) = assertion;
3988 /* The new ASSERT_EXPR, creates a new SSA name that replaces the
3989 operand of the ASSERT_EXPR. Register the new name and the old one
3990 in the replacement table so that we can fix the SSA web after
3991 adding all the ASSERT_EXPRs. */
3992 register_new_name_mapping (n, v);
3998 /* Return false if EXPR is a predicate expression involving floating
4002 fp_predicate (gimple stmt)
4004 GIMPLE_CHECK (stmt, GIMPLE_COND);
4006 return FLOAT_TYPE_P (TREE_TYPE (gimple_cond_lhs (stmt)));
4010 /* If the range of values taken by OP can be inferred after STMT executes,
4011 return the comparison code (COMP_CODE_P) and value (VAL_P) that
4012 describes the inferred range. Return true if a range could be
4016 infer_value_range (gimple stmt, tree op, enum tree_code *comp_code_p, tree *val_p)
4019 *comp_code_p = ERROR_MARK;
4021 /* Do not attempt to infer anything in names that flow through
4023 if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (op))
4026 /* Similarly, don't infer anything from statements that may throw
4028 if (stmt_could_throw_p (stmt))
4031 /* If STMT is the last statement of a basic block with no
4032 successors, there is no point inferring anything about any of its
4033 operands. We would not be able to find a proper insertion point
4034 for the assertion, anyway. */
4035 if (stmt_ends_bb_p (stmt) && EDGE_COUNT (gimple_bb (stmt)->succs) == 0)
4038 /* We can only assume that a pointer dereference will yield
4039 non-NULL if -fdelete-null-pointer-checks is enabled. */
4040 if (flag_delete_null_pointer_checks
4041 && POINTER_TYPE_P (TREE_TYPE (op))
4042 && gimple_code (stmt) != GIMPLE_ASM)
4044 unsigned num_uses, num_loads, num_stores;
4046 count_uses_and_derefs (op, stmt, &num_uses, &num_loads, &num_stores);
4047 if (num_loads + num_stores > 0)
4049 *val_p = build_int_cst (TREE_TYPE (op), 0);
4050 *comp_code_p = NE_EXPR;
4059 void dump_asserts_for (FILE *, tree);
4060 void debug_asserts_for (tree);
4061 void dump_all_asserts (FILE *);
4062 void debug_all_asserts (void);
4064 /* Dump all the registered assertions for NAME to FILE. */
4067 dump_asserts_for (FILE *file, tree name)
4071 fprintf (file, "Assertions to be inserted for ");
4072 print_generic_expr (file, name, 0);
4073 fprintf (file, "\n");
4075 loc = asserts_for[SSA_NAME_VERSION (name)];
4078 fprintf (file, "\t");
4079 print_gimple_stmt (file, gsi_stmt (loc->si), 0, 0);
4080 fprintf (file, "\n\tBB #%d", loc->bb->index);
4083 fprintf (file, "\n\tEDGE %d->%d", loc->e->src->index,
4084 loc->e->dest->index);
4085 dump_edge_info (file, loc->e, 0);
4087 fprintf (file, "\n\tPREDICATE: ");
4088 print_generic_expr (file, name, 0);
4089 fprintf (file, " %s ", tree_code_name[(int)loc->comp_code]);
4090 print_generic_expr (file, loc->val, 0);
4091 fprintf (file, "\n\n");
4095 fprintf (file, "\n");
4099 /* Dump all the registered assertions for NAME to stderr. */
4102 debug_asserts_for (tree name)
4104 dump_asserts_for (stderr, name);
4108 /* Dump all the registered assertions for all the names to FILE. */
4111 dump_all_asserts (FILE *file)
4116 fprintf (file, "\nASSERT_EXPRs to be inserted\n\n");
4117 EXECUTE_IF_SET_IN_BITMAP (need_assert_for, 0, i, bi)
4118 dump_asserts_for (file, ssa_name (i));
4119 fprintf (file, "\n");
4123 /* Dump all the registered assertions for all the names to stderr. */
4126 debug_all_asserts (void)
4128 dump_all_asserts (stderr);
4132 /* If NAME doesn't have an ASSERT_EXPR registered for asserting
4133 'EXPR COMP_CODE VAL' at a location that dominates block BB or
4134 E->DEST, then register this location as a possible insertion point
4135 for ASSERT_EXPR <NAME, EXPR COMP_CODE VAL>.
4137 BB, E and SI provide the exact insertion point for the new
4138 ASSERT_EXPR. If BB is NULL, then the ASSERT_EXPR is to be inserted
4139 on edge E. Otherwise, if E is NULL, the ASSERT_EXPR is inserted on
4140 BB. If SI points to a COND_EXPR or a SWITCH_EXPR statement, then E
4141 must not be NULL. */
4144 register_new_assert_for (tree name, tree expr,
4145 enum tree_code comp_code,
4149 gimple_stmt_iterator si)
4151 assert_locus_t n, loc, last_loc;
4152 basic_block dest_bb;
4154 gcc_checking_assert (bb == NULL || e == NULL);
4157 gcc_checking_assert (gimple_code (gsi_stmt (si)) != GIMPLE_COND
4158 && gimple_code (gsi_stmt (si)) != GIMPLE_SWITCH);
4160 /* Never build an assert comparing against an integer constant with
4161 TREE_OVERFLOW set. This confuses our undefined overflow warning
4163 if (TREE_CODE (val) == INTEGER_CST
4164 && TREE_OVERFLOW (val))
4165 val = build_int_cst_wide (TREE_TYPE (val),
4166 TREE_INT_CST_LOW (val), TREE_INT_CST_HIGH (val));
4168 /* The new assertion A will be inserted at BB or E. We need to
4169 determine if the new location is dominated by a previously
4170 registered location for A. If we are doing an edge insertion,
4171 assume that A will be inserted at E->DEST. Note that this is not
4174 If E is a critical edge, it will be split. But even if E is
4175 split, the new block will dominate the same set of blocks that
4178 The reverse, however, is not true, blocks dominated by E->DEST
4179 will not be dominated by the new block created to split E. So,
4180 if the insertion location is on a critical edge, we will not use
4181 the new location to move another assertion previously registered
4182 at a block dominated by E->DEST. */
4183 dest_bb = (bb) ? bb : e->dest;
4185 /* If NAME already has an ASSERT_EXPR registered for COMP_CODE and
4186 VAL at a block dominating DEST_BB, then we don't need to insert a new
4187 one. Similarly, if the same assertion already exists at a block
4188 dominated by DEST_BB and the new location is not on a critical
4189 edge, then update the existing location for the assertion (i.e.,
4190 move the assertion up in the dominance tree).
4192 Note, this is implemented as a simple linked list because there
4193 should not be more than a handful of assertions registered per
4194 name. If this becomes a performance problem, a table hashed by
4195 COMP_CODE and VAL could be implemented. */
4196 loc = asserts_for[SSA_NAME_VERSION (name)];
4200 if (loc->comp_code == comp_code
4202 || operand_equal_p (loc->val, val, 0))
4203 && (loc->expr == expr
4204 || operand_equal_p (loc->expr, expr, 0)))
4206 /* If the assertion NAME COMP_CODE VAL has already been
4207 registered at a basic block that dominates DEST_BB, then
4208 we don't need to insert the same assertion again. Note
4209 that we don't check strict dominance here to avoid
4210 replicating the same assertion inside the same basic
4211 block more than once (e.g., when a pointer is
4212 dereferenced several times inside a block).
4214 An exception to this rule are edge insertions. If the
4215 new assertion is to be inserted on edge E, then it will
4216 dominate all the other insertions that we may want to
4217 insert in DEST_BB. So, if we are doing an edge
4218 insertion, don't do this dominance check. */
4220 && dominated_by_p (CDI_DOMINATORS, dest_bb, loc->bb))
4223 /* Otherwise, if E is not a critical edge and DEST_BB
4224 dominates the existing location for the assertion, move
4225 the assertion up in the dominance tree by updating its
4226 location information. */
4227 if ((e == NULL || !EDGE_CRITICAL_P (e))
4228 && dominated_by_p (CDI_DOMINATORS, loc->bb, dest_bb))
4237 /* Update the last node of the list and move to the next one. */
4242 /* If we didn't find an assertion already registered for
4243 NAME COMP_CODE VAL, add a new one at the end of the list of
4244 assertions associated with NAME. */
4245 n = XNEW (struct assert_locus_d);
4249 n->comp_code = comp_code;
4257 asserts_for[SSA_NAME_VERSION (name)] = n;
4259 bitmap_set_bit (need_assert_for, SSA_NAME_VERSION (name));
4262 /* (COND_OP0 COND_CODE COND_OP1) is a predicate which uses NAME.
4263 Extract a suitable test code and value and store them into *CODE_P and
4264 *VAL_P so the predicate is normalized to NAME *CODE_P *VAL_P.
4266 If no extraction was possible, return FALSE, otherwise return TRUE.
4268 If INVERT is true, then we invert the result stored into *CODE_P. */
4271 extract_code_and_val_from_cond_with_ops (tree name, enum tree_code cond_code,
4272 tree cond_op0, tree cond_op1,
4273 bool invert, enum tree_code *code_p,
4276 enum tree_code comp_code;
4279 /* Otherwise, we have a comparison of the form NAME COMP VAL
4280 or VAL COMP NAME. */
4281 if (name == cond_op1)
4283 /* If the predicate is of the form VAL COMP NAME, flip
4284 COMP around because we need to register NAME as the
4285 first operand in the predicate. */
4286 comp_code = swap_tree_comparison (cond_code);
4291 /* The comparison is of the form NAME COMP VAL, so the
4292 comparison code remains unchanged. */
4293 comp_code = cond_code;
4297 /* Invert the comparison code as necessary. */
4299 comp_code = invert_tree_comparison (comp_code, 0);
4301 /* VRP does not handle float types. */
4302 if (SCALAR_FLOAT_TYPE_P (TREE_TYPE (val)))
4305 /* Do not register always-false predicates.
4306 FIXME: this works around a limitation in fold() when dealing with
4307 enumerations. Given 'enum { N1, N2 } x;', fold will not
4308 fold 'if (x > N2)' to 'if (0)'. */
4309 if ((comp_code == GT_EXPR || comp_code == LT_EXPR)
4310 && INTEGRAL_TYPE_P (TREE_TYPE (val)))
4312 tree min = TYPE_MIN_VALUE (TREE_TYPE (val));
4313 tree max = TYPE_MAX_VALUE (TREE_TYPE (val));
4315 if (comp_code == GT_EXPR
4317 || compare_values (val, max) == 0))
4320 if (comp_code == LT_EXPR
4322 || compare_values (val, min) == 0))
4325 *code_p = comp_code;
4330 /* Try to register an edge assertion for SSA name NAME on edge E for
4331 the condition COND contributing to the conditional jump pointed to by BSI.
4332 Invert the condition COND if INVERT is true.
4333 Return true if an assertion for NAME could be registered. */
4336 register_edge_assert_for_2 (tree name, edge e, gimple_stmt_iterator bsi,
4337 enum tree_code cond_code,
4338 tree cond_op0, tree cond_op1, bool invert)
4341 enum tree_code comp_code;
4342 bool retval = false;
4344 if (!extract_code_and_val_from_cond_with_ops (name, cond_code,
4347 invert, &comp_code, &val))
4350 /* Only register an ASSERT_EXPR if NAME was found in the sub-graph
4351 reachable from E. */
4352 if (live_on_edge (e, name)
4353 && !has_single_use (name))
4355 register_new_assert_for (name, name, comp_code, val, NULL, e, bsi);
4359 /* In the case of NAME <= CST and NAME being defined as
4360 NAME = (unsigned) NAME2 + CST2 we can assert NAME2 >= -CST2
4361 and NAME2 <= CST - CST2. We can do the same for NAME > CST.
4362 This catches range and anti-range tests. */
4363 if ((comp_code == LE_EXPR
4364 || comp_code == GT_EXPR)
4365 && TREE_CODE (val) == INTEGER_CST
4366 && TYPE_UNSIGNED (TREE_TYPE (val)))
4368 gimple def_stmt = SSA_NAME_DEF_STMT (name);
4369 tree cst2 = NULL_TREE, name2 = NULL_TREE, name3 = NULL_TREE;
4371 /* Extract CST2 from the (optional) addition. */
4372 if (is_gimple_assign (def_stmt)
4373 && gimple_assign_rhs_code (def_stmt) == PLUS_EXPR)
4375 name2 = gimple_assign_rhs1 (def_stmt);
4376 cst2 = gimple_assign_rhs2 (def_stmt);
4377 if (TREE_CODE (name2) == SSA_NAME
4378 && TREE_CODE (cst2) == INTEGER_CST)
4379 def_stmt = SSA_NAME_DEF_STMT (name2);
4382 /* Extract NAME2 from the (optional) sign-changing cast. */
4383 if (gimple_assign_cast_p (def_stmt))
4385 if (CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (def_stmt))
4386 && ! TYPE_UNSIGNED (TREE_TYPE (gimple_assign_rhs1 (def_stmt)))
4387 && (TYPE_PRECISION (gimple_expr_type (def_stmt))
4388 == TYPE_PRECISION (TREE_TYPE (gimple_assign_rhs1 (def_stmt)))))
4389 name3 = gimple_assign_rhs1 (def_stmt);
4392 /* If name3 is used later, create an ASSERT_EXPR for it. */
4393 if (name3 != NULL_TREE
4394 && TREE_CODE (name3) == SSA_NAME
4395 && (cst2 == NULL_TREE
4396 || TREE_CODE (cst2) == INTEGER_CST)
4397 && INTEGRAL_TYPE_P (TREE_TYPE (name3))
4398 && live_on_edge (e, name3)
4399 && !has_single_use (name3))
4403 /* Build an expression for the range test. */
4404 tmp = build1 (NOP_EXPR, TREE_TYPE (name), name3);
4405 if (cst2 != NULL_TREE)
4406 tmp = build2 (PLUS_EXPR, TREE_TYPE (name), tmp, cst2);
4410 fprintf (dump_file, "Adding assert for ");
4411 print_generic_expr (dump_file, name3, 0);
4412 fprintf (dump_file, " from ");
4413 print_generic_expr (dump_file, tmp, 0);
4414 fprintf (dump_file, "\n");
4417 register_new_assert_for (name3, tmp, comp_code, val, NULL, e, bsi);
4422 /* If name2 is used later, create an ASSERT_EXPR for it. */
4423 if (name2 != NULL_TREE
4424 && TREE_CODE (name2) == SSA_NAME
4425 && TREE_CODE (cst2) == INTEGER_CST
4426 && INTEGRAL_TYPE_P (TREE_TYPE (name2))
4427 && live_on_edge (e, name2)
4428 && !has_single_use (name2))
4432 /* Build an expression for the range test. */
4434 if (TREE_TYPE (name) != TREE_TYPE (name2))
4435 tmp = build1 (NOP_EXPR, TREE_TYPE (name), tmp);
4436 if (cst2 != NULL_TREE)
4437 tmp = build2 (PLUS_EXPR, TREE_TYPE (name), tmp, cst2);
4441 fprintf (dump_file, "Adding assert for ");
4442 print_generic_expr (dump_file, name2, 0);
4443 fprintf (dump_file, " from ");
4444 print_generic_expr (dump_file, tmp, 0);
4445 fprintf (dump_file, "\n");
4448 register_new_assert_for (name2, tmp, comp_code, val, NULL, e, bsi);
4457 /* OP is an operand of a truth value expression which is known to have
4458 a particular value. Register any asserts for OP and for any
4459 operands in OP's defining statement.
4461 If CODE is EQ_EXPR, then we want to register OP is zero (false),
4462 if CODE is NE_EXPR, then we want to register OP is nonzero (true). */
4465 register_edge_assert_for_1 (tree op, enum tree_code code,
4466 edge e, gimple_stmt_iterator bsi)
4468 bool retval = false;
4471 enum tree_code rhs_code;
4473 /* We only care about SSA_NAMEs. */
4474 if (TREE_CODE (op) != SSA_NAME)
4477 /* We know that OP will have a zero or nonzero value. If OP is used
4478 more than once go ahead and register an assert for OP.
4480 The FOUND_IN_SUBGRAPH support is not helpful in this situation as
4481 it will always be set for OP (because OP is used in a COND_EXPR in
4483 if (!has_single_use (op))
4485 val = build_int_cst (TREE_TYPE (op), 0);
4486 register_new_assert_for (op, op, code, val, NULL, e, bsi);
4490 /* Now look at how OP is set. If it's set from a comparison,
4491 a truth operation or some bit operations, then we may be able
4492 to register information about the operands of that assignment. */
4493 op_def = SSA_NAME_DEF_STMT (op);
4494 if (gimple_code (op_def) != GIMPLE_ASSIGN)
4497 rhs_code = gimple_assign_rhs_code (op_def);
4499 if (TREE_CODE_CLASS (rhs_code) == tcc_comparison)
4501 bool invert = (code == EQ_EXPR ? true : false);
4502 tree op0 = gimple_assign_rhs1 (op_def);
4503 tree op1 = gimple_assign_rhs2 (op_def);
4505 if (TREE_CODE (op0) == SSA_NAME)
4506 retval |= register_edge_assert_for_2 (op0, e, bsi, rhs_code, op0, op1,
4508 if (TREE_CODE (op1) == SSA_NAME)
4509 retval |= register_edge_assert_for_2 (op1, e, bsi, rhs_code, op0, op1,
4512 else if ((code == NE_EXPR
4513 && gimple_assign_rhs_code (op_def) == BIT_AND_EXPR)
4515 && gimple_assign_rhs_code (op_def) == BIT_IOR_EXPR))
4517 /* Recurse on each operand. */
4518 retval |= register_edge_assert_for_1 (gimple_assign_rhs1 (op_def),
4520 retval |= register_edge_assert_for_1 (gimple_assign_rhs2 (op_def),
4523 else if (gimple_assign_rhs_code (op_def) == BIT_NOT_EXPR
4524 && TYPE_PRECISION (TREE_TYPE (gimple_assign_lhs (op_def))) == 1)
4526 /* Recurse, flipping CODE. */
4527 code = invert_tree_comparison (code, false);
4528 retval |= register_edge_assert_for_1 (gimple_assign_rhs1 (op_def),
4531 else if (gimple_assign_rhs_code (op_def) == SSA_NAME)
4533 /* Recurse through the copy. */
4534 retval |= register_edge_assert_for_1 (gimple_assign_rhs1 (op_def),
4537 else if (CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (op_def)))
4539 /* Recurse through the type conversion. */
4540 retval |= register_edge_assert_for_1 (gimple_assign_rhs1 (op_def),
4547 /* Try to register an edge assertion for SSA name NAME on edge E for
4548 the condition COND contributing to the conditional jump pointed to by SI.
4549 Return true if an assertion for NAME could be registered. */
4552 register_edge_assert_for (tree name, edge e, gimple_stmt_iterator si,
4553 enum tree_code cond_code, tree cond_op0,
4557 enum tree_code comp_code;
4558 bool retval = false;
4559 bool is_else_edge = (e->flags & EDGE_FALSE_VALUE) != 0;
4561 /* Do not attempt to infer anything in names that flow through
4563 if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (name))
4566 if (!extract_code_and_val_from_cond_with_ops (name, cond_code,
4572 /* Register ASSERT_EXPRs for name. */
4573 retval |= register_edge_assert_for_2 (name, e, si, cond_code, cond_op0,
4574 cond_op1, is_else_edge);
4577 /* If COND is effectively an equality test of an SSA_NAME against
4578 the value zero or one, then we may be able to assert values
4579 for SSA_NAMEs which flow into COND. */
4581 /* In the case of NAME == 1 or NAME != 0, for BIT_AND_EXPR defining
4582 statement of NAME we can assert both operands of the BIT_AND_EXPR
4583 have nonzero value. */
4584 if (((comp_code == EQ_EXPR && integer_onep (val))
4585 || (comp_code == NE_EXPR && integer_zerop (val))))
4587 gimple def_stmt = SSA_NAME_DEF_STMT (name);
4589 if (is_gimple_assign (def_stmt)
4590 && gimple_assign_rhs_code (def_stmt) == BIT_AND_EXPR)
4592 tree op0 = gimple_assign_rhs1 (def_stmt);
4593 tree op1 = gimple_assign_rhs2 (def_stmt);
4594 retval |= register_edge_assert_for_1 (op0, NE_EXPR, e, si);
4595 retval |= register_edge_assert_for_1 (op1, NE_EXPR, e, si);
4599 /* In the case of NAME == 0 or NAME != 1, for BIT_IOR_EXPR defining
4600 statement of NAME we can assert both operands of the BIT_IOR_EXPR
4602 if (((comp_code == EQ_EXPR && integer_zerop (val))
4603 || (comp_code == NE_EXPR && integer_onep (val))))
4605 gimple def_stmt = SSA_NAME_DEF_STMT (name);
4607 /* For BIT_IOR_EXPR only if NAME == 0 both operands have
4608 necessarily zero value, or if type-precision is one. */
4609 if (is_gimple_assign (def_stmt)
4610 && (gimple_assign_rhs_code (def_stmt) == BIT_IOR_EXPR
4611 && (TYPE_PRECISION (TREE_TYPE (name)) == 1
4612 || comp_code == EQ_EXPR)))
4614 tree op0 = gimple_assign_rhs1 (def_stmt);
4615 tree op1 = gimple_assign_rhs2 (def_stmt);
4616 retval |= register_edge_assert_for_1 (op0, EQ_EXPR, e, si);
4617 retval |= register_edge_assert_for_1 (op1, EQ_EXPR, e, si);
4625 /* Determine whether the outgoing edges of BB should receive an
4626 ASSERT_EXPR for each of the operands of BB's LAST statement.
4627 The last statement of BB must be a COND_EXPR.
4629 If any of the sub-graphs rooted at BB have an interesting use of
4630 the predicate operands, an assert location node is added to the
4631 list of assertions for the corresponding operands. */
4634 find_conditional_asserts (basic_block bb, gimple last)
4637 gimple_stmt_iterator bsi;
4643 need_assert = false;
4644 bsi = gsi_for_stmt (last);
4646 /* Look for uses of the operands in each of the sub-graphs
4647 rooted at BB. We need to check each of the outgoing edges
4648 separately, so that we know what kind of ASSERT_EXPR to
4650 FOR_EACH_EDGE (e, ei, bb->succs)
4655 /* Register the necessary assertions for each operand in the
4656 conditional predicate. */
4657 FOR_EACH_SSA_TREE_OPERAND (op, last, iter, SSA_OP_USE)
4659 need_assert |= register_edge_assert_for (op, e, bsi,
4660 gimple_cond_code (last),
4661 gimple_cond_lhs (last),
4662 gimple_cond_rhs (last));
4675 /* Compare two case labels sorting first by the destination bb index
4676 and then by the case value. */
4679 compare_case_labels (const void *p1, const void *p2)
4681 const struct case_info *ci1 = (const struct case_info *) p1;
4682 const struct case_info *ci2 = (const struct case_info *) p2;
4683 int idx1 = ci1->bb->index;
4684 int idx2 = ci2->bb->index;
4688 else if (idx1 == idx2)
4690 /* Make sure the default label is first in a group. */
4691 if (!CASE_LOW (ci1->expr))
4693 else if (!CASE_LOW (ci2->expr))
4696 return tree_int_cst_compare (CASE_LOW (ci1->expr),
4697 CASE_LOW (ci2->expr));
4703 /* Determine whether the outgoing edges of BB should receive an
4704 ASSERT_EXPR for each of the operands of BB's LAST statement.
4705 The last statement of BB must be a SWITCH_EXPR.
4707 If any of the sub-graphs rooted at BB have an interesting use of
4708 the predicate operands, an assert location node is added to the
4709 list of assertions for the corresponding operands. */
4712 find_switch_asserts (basic_block bb, gimple last)
4715 gimple_stmt_iterator bsi;
4718 struct case_info *ci;
4719 size_t n = gimple_switch_num_labels (last);
4720 #if GCC_VERSION >= 4000
4723 /* Work around GCC 3.4 bug (PR 37086). */
4724 volatile unsigned int idx;
4727 need_assert = false;
4728 bsi = gsi_for_stmt (last);
4729 op = gimple_switch_index (last);
4730 if (TREE_CODE (op) != SSA_NAME)
4733 /* Build a vector of case labels sorted by destination label. */
4734 ci = XNEWVEC (struct case_info, n);
4735 for (idx = 0; idx < n; ++idx)
4737 ci[idx].expr = gimple_switch_label (last, idx);
4738 ci[idx].bb = label_to_block (CASE_LABEL (ci[idx].expr));
4740 qsort (ci, n, sizeof (struct case_info), compare_case_labels);
4742 for (idx = 0; idx < n; ++idx)
4745 tree cl = ci[idx].expr;
4746 basic_block cbb = ci[idx].bb;
4748 min = CASE_LOW (cl);
4749 max = CASE_HIGH (cl);
4751 /* If there are multiple case labels with the same destination
4752 we need to combine them to a single value range for the edge. */
4753 if (idx + 1 < n && cbb == ci[idx + 1].bb)
4755 /* Skip labels until the last of the group. */
4758 } while (idx < n && cbb == ci[idx].bb);
4761 /* Pick up the maximum of the case label range. */
4762 if (CASE_HIGH (ci[idx].expr))
4763 max = CASE_HIGH (ci[idx].expr);
4765 max = CASE_LOW (ci[idx].expr);
4768 /* Nothing to do if the range includes the default label until we
4769 can register anti-ranges. */
4770 if (min == NULL_TREE)
4773 /* Find the edge to register the assert expr on. */
4774 e = find_edge (bb, cbb);
4776 /* Register the necessary assertions for the operand in the
4778 need_assert |= register_edge_assert_for (op, e, bsi,
4779 max ? GE_EXPR : EQ_EXPR,
4781 fold_convert (TREE_TYPE (op),
4785 need_assert |= register_edge_assert_for (op, e, bsi, LE_EXPR,
4787 fold_convert (TREE_TYPE (op),
4797 /* Traverse all the statements in block BB looking for statements that
4798 may generate useful assertions for the SSA names in their operand.
4799 If a statement produces a useful assertion A for name N_i, then the
4800 list of assertions already generated for N_i is scanned to
4801 determine if A is actually needed.
4803 If N_i already had the assertion A at a location dominating the
4804 current location, then nothing needs to be done. Otherwise, the
4805 new location for A is recorded instead.
4807 1- For every statement S in BB, all the variables used by S are
4808 added to bitmap FOUND_IN_SUBGRAPH.
4810 2- If statement S uses an operand N in a way that exposes a known
4811 value range for N, then if N was not already generated by an
4812 ASSERT_EXPR, create a new assert location for N. For instance,
4813 if N is a pointer and the statement dereferences it, we can
4814 assume that N is not NULL.
4816 3- COND_EXPRs are a special case of #2. We can derive range
4817 information from the predicate but need to insert different
4818 ASSERT_EXPRs for each of the sub-graphs rooted at the
4819 conditional block. If the last statement of BB is a conditional
4820 expression of the form 'X op Y', then
4822 a) Remove X and Y from the set FOUND_IN_SUBGRAPH.
4824 b) If the conditional is the only entry point to the sub-graph
4825 corresponding to the THEN_CLAUSE, recurse into it. On
4826 return, if X and/or Y are marked in FOUND_IN_SUBGRAPH, then
4827 an ASSERT_EXPR is added for the corresponding variable.
4829 c) Repeat step (b) on the ELSE_CLAUSE.
4831 d) Mark X and Y in FOUND_IN_SUBGRAPH.
4840 In this case, an assertion on the THEN clause is useful to
4841 determine that 'a' is always 9 on that edge. However, an assertion
4842 on the ELSE clause would be unnecessary.
4844 4- If BB does not end in a conditional expression, then we recurse
4845 into BB's dominator children.
4847 At the end of the recursive traversal, every SSA name will have a
4848 list of locations where ASSERT_EXPRs should be added. When a new
4849 location for name N is found, it is registered by calling
4850 register_new_assert_for. That function keeps track of all the
4851 registered assertions to prevent adding unnecessary assertions.
4852 For instance, if a pointer P_4 is dereferenced more than once in a
4853 dominator tree, only the location dominating all the dereference of
4854 P_4 will receive an ASSERT_EXPR.
4856 If this function returns true, then it means that there are names
4857 for which we need to generate ASSERT_EXPRs. Those assertions are
4858 inserted by process_assert_insertions. */
4861 find_assert_locations_1 (basic_block bb, sbitmap live)
4863 gimple_stmt_iterator si;
4868 need_assert = false;
4869 last = last_stmt (bb);
4871 /* If BB's last statement is a conditional statement involving integer
4872 operands, determine if we need to add ASSERT_EXPRs. */
4874 && gimple_code (last) == GIMPLE_COND
4875 && !fp_predicate (last)
4876 && !ZERO_SSA_OPERANDS (last, SSA_OP_USE))
4877 need_assert |= find_conditional_asserts (bb, last);
4879 /* If BB's last statement is a switch statement involving integer
4880 operands, determine if we need to add ASSERT_EXPRs. */
4882 && gimple_code (last) == GIMPLE_SWITCH
4883 && !ZERO_SSA_OPERANDS (last, SSA_OP_USE))
4884 need_assert |= find_switch_asserts (bb, last);
4886 /* Traverse all the statements in BB marking used names and looking
4887 for statements that may infer assertions for their used operands. */
4888 for (si = gsi_start_bb (bb); !gsi_end_p (si); gsi_next (&si))
4894 stmt = gsi_stmt (si);
4896 if (is_gimple_debug (stmt))
4899 /* See if we can derive an assertion for any of STMT's operands. */
4900 FOR_EACH_SSA_TREE_OPERAND (op, stmt, i, SSA_OP_USE)
4903 enum tree_code comp_code;
4905 /* Mark OP in our live bitmap. */
4906 SET_BIT (live, SSA_NAME_VERSION (op));
4908 /* If OP is used in such a way that we can infer a value
4909 range for it, and we don't find a previous assertion for
4910 it, create a new assertion location node for OP. */
4911 if (infer_value_range (stmt, op, &comp_code, &value))
4913 /* If we are able to infer a nonzero value range for OP,
4914 then walk backwards through the use-def chain to see if OP
4915 was set via a typecast.
4917 If so, then we can also infer a nonzero value range
4918 for the operand of the NOP_EXPR. */
4919 if (comp_code == NE_EXPR && integer_zerop (value))
4922 gimple def_stmt = SSA_NAME_DEF_STMT (t);
4924 while (is_gimple_assign (def_stmt)
4925 && gimple_assign_rhs_code (def_stmt) == NOP_EXPR
4927 (gimple_assign_rhs1 (def_stmt)) == SSA_NAME
4929 (TREE_TYPE (gimple_assign_rhs1 (def_stmt))))
4931 t = gimple_assign_rhs1 (def_stmt);
4932 def_stmt = SSA_NAME_DEF_STMT (t);
4934 /* Note we want to register the assert for the
4935 operand of the NOP_EXPR after SI, not after the
4937 if (! has_single_use (t))
4939 register_new_assert_for (t, t, comp_code, value,
4946 /* If OP is used only once, namely in this STMT, don't
4947 bother creating an ASSERT_EXPR for it. Such an
4948 ASSERT_EXPR would do nothing but increase compile time. */
4949 if (!has_single_use (op))
4951 register_new_assert_for (op, op, comp_code, value,
4959 /* Traverse all PHI nodes in BB marking used operands. */
4960 for (si = gsi_start_phis (bb); !gsi_end_p(si); gsi_next (&si))
4962 use_operand_p arg_p;
4964 phi = gsi_stmt (si);
4966 FOR_EACH_PHI_ARG (arg_p, phi, i, SSA_OP_USE)
4968 tree arg = USE_FROM_PTR (arg_p);
4969 if (TREE_CODE (arg) == SSA_NAME)
4970 SET_BIT (live, SSA_NAME_VERSION (arg));
4977 /* Do an RPO walk over the function computing SSA name liveness
4978 on-the-fly and deciding on assert expressions to insert.
4979 Returns true if there are assert expressions to be inserted. */
4982 find_assert_locations (void)
4984 int *rpo = XCNEWVEC (int, last_basic_block + NUM_FIXED_BLOCKS);
4985 int *bb_rpo = XCNEWVEC (int, last_basic_block + NUM_FIXED_BLOCKS);
4986 int *last_rpo = XCNEWVEC (int, last_basic_block + NUM_FIXED_BLOCKS);
4990 live = XCNEWVEC (sbitmap, last_basic_block + NUM_FIXED_BLOCKS);
4991 rpo_cnt = pre_and_rev_post_order_compute (NULL, rpo, false);
4992 for (i = 0; i < rpo_cnt; ++i)
4995 need_asserts = false;
4996 for (i = rpo_cnt-1; i >= 0; --i)
4998 basic_block bb = BASIC_BLOCK (rpo[i]);
5004 live[rpo[i]] = sbitmap_alloc (num_ssa_names);
5005 sbitmap_zero (live[rpo[i]]);
5008 /* Process BB and update the live information with uses in
5010 need_asserts |= find_assert_locations_1 (bb, live[rpo[i]]);
5012 /* Merge liveness into the predecessor blocks and free it. */
5013 if (!sbitmap_empty_p (live[rpo[i]]))
5016 FOR_EACH_EDGE (e, ei, bb->preds)
5018 int pred = e->src->index;
5019 if (e->flags & EDGE_DFS_BACK)
5024 live[pred] = sbitmap_alloc (num_ssa_names);
5025 sbitmap_zero (live[pred]);
5027 sbitmap_a_or_b (live[pred], live[pred], live[rpo[i]]);
5029 if (bb_rpo[pred] < pred_rpo)
5030 pred_rpo = bb_rpo[pred];
5033 /* Record the RPO number of the last visited block that needs
5034 live information from this block. */
5035 last_rpo[rpo[i]] = pred_rpo;
5039 sbitmap_free (live[rpo[i]]);
5040 live[rpo[i]] = NULL;
5043 /* We can free all successors live bitmaps if all their
5044 predecessors have been visited already. */
5045 FOR_EACH_EDGE (e, ei, bb->succs)
5046 if (last_rpo[e->dest->index] == i
5047 && live[e->dest->index])
5049 sbitmap_free (live[e->dest->index]);
5050 live[e->dest->index] = NULL;
5055 XDELETEVEC (bb_rpo);
5056 XDELETEVEC (last_rpo);
5057 for (i = 0; i < last_basic_block + NUM_FIXED_BLOCKS; ++i)
5059 sbitmap_free (live[i]);
5062 return need_asserts;
5065 /* Create an ASSERT_EXPR for NAME and insert it in the location
5066 indicated by LOC. Return true if we made any edge insertions. */
5069 process_assert_insertions_for (tree name, assert_locus_t loc)
5071 /* Build the comparison expression NAME_i COMP_CODE VAL. */
5078 /* If we have X <=> X do not insert an assert expr for that. */
5079 if (loc->expr == loc->val)
5082 cond = build2 (loc->comp_code, boolean_type_node, loc->expr, loc->val);
5083 assert_stmt = build_assert_expr_for (cond, name);
5086 /* We have been asked to insert the assertion on an edge. This
5087 is used only by COND_EXPR and SWITCH_EXPR assertions. */
5088 gcc_checking_assert (gimple_code (gsi_stmt (loc->si)) == GIMPLE_COND
5089 || (gimple_code (gsi_stmt (loc->si))
5092 gsi_insert_on_edge (loc->e, assert_stmt);
5096 /* Otherwise, we can insert right after LOC->SI iff the
5097 statement must not be the last statement in the block. */
5098 stmt = gsi_stmt (loc->si);
5099 if (!stmt_ends_bb_p (stmt))
5101 gsi_insert_after (&loc->si, assert_stmt, GSI_SAME_STMT);
5105 /* If STMT must be the last statement in BB, we can only insert new
5106 assertions on the non-abnormal edge out of BB. Note that since
5107 STMT is not control flow, there may only be one non-abnormal edge
5109 FOR_EACH_EDGE (e, ei, loc->bb->succs)
5110 if (!(e->flags & EDGE_ABNORMAL))
5112 gsi_insert_on_edge (e, assert_stmt);
5120 /* Process all the insertions registered for every name N_i registered
5121 in NEED_ASSERT_FOR. The list of assertions to be inserted are
5122 found in ASSERTS_FOR[i]. */
5125 process_assert_insertions (void)
5129 bool update_edges_p = false;
5130 int num_asserts = 0;
5132 if (dump_file && (dump_flags & TDF_DETAILS))
5133 dump_all_asserts (dump_file);
5135 EXECUTE_IF_SET_IN_BITMAP (need_assert_for, 0, i, bi)
5137 assert_locus_t loc = asserts_for[i];
5142 assert_locus_t next = loc->next;
5143 update_edges_p |= process_assert_insertions_for (ssa_name (i), loc);
5151 gsi_commit_edge_inserts ();
5153 statistics_counter_event (cfun, "Number of ASSERT_EXPR expressions inserted",
5158 /* Traverse the flowgraph looking for conditional jumps to insert range
5159 expressions. These range expressions are meant to provide information
5160 to optimizations that need to reason in terms of value ranges. They
5161 will not be expanded into RTL. For instance, given:
5170 this pass will transform the code into:
5176 x = ASSERT_EXPR <x, x < y>
5181 y = ASSERT_EXPR <y, x <= y>
5185 The idea is that once copy and constant propagation have run, other
5186 optimizations will be able to determine what ranges of values can 'x'
5187 take in different paths of the code, simply by checking the reaching
5188 definition of 'x'. */
5191 insert_range_assertions (void)
5193 need_assert_for = BITMAP_ALLOC (NULL);
5194 asserts_for = XCNEWVEC (assert_locus_t, num_ssa_names);
5196 calculate_dominance_info (CDI_DOMINATORS);
5198 if (find_assert_locations ())
5200 process_assert_insertions ();
5201 update_ssa (TODO_update_ssa_no_phi);
5204 if (dump_file && (dump_flags & TDF_DETAILS))
5206 fprintf (dump_file, "\nSSA form after inserting ASSERT_EXPRs\n");
5207 dump_function_to_file (current_function_decl, dump_file, dump_flags);
5211 BITMAP_FREE (need_assert_for);
5214 /* Checks one ARRAY_REF in REF, located at LOCUS. Ignores flexible arrays
5215 and "struct" hacks. If VRP can determine that the
5216 array subscript is a constant, check if it is outside valid
5217 range. If the array subscript is a RANGE, warn if it is
5218 non-overlapping with valid range.
5219 IGNORE_OFF_BY_ONE is true if the ARRAY_REF is inside a ADDR_EXPR. */
5222 check_array_ref (location_t location, tree ref, bool ignore_off_by_one)
5224 value_range_t* vr = NULL;
5225 tree low_sub, up_sub;
5226 tree low_bound, up_bound, up_bound_p1;
5229 if (TREE_NO_WARNING (ref))
5232 low_sub = up_sub = TREE_OPERAND (ref, 1);
5233 up_bound = array_ref_up_bound (ref);
5235 /* Can not check flexible arrays. */
5237 || TREE_CODE (up_bound) != INTEGER_CST)
5240 /* Accesses to trailing arrays via pointers may access storage
5241 beyond the types array bounds. */
5242 base = get_base_address (ref);
5243 if (base && TREE_CODE (base) == MEM_REF)
5245 tree cref, next = NULL_TREE;
5247 if (TREE_CODE (TREE_OPERAND (ref, 0)) != COMPONENT_REF)
5250 cref = TREE_OPERAND (ref, 0);
5251 if (TREE_CODE (TREE_TYPE (TREE_OPERAND (cref, 0))) == RECORD_TYPE)
5252 for (next = DECL_CHAIN (TREE_OPERAND (cref, 1));
5253 next && TREE_CODE (next) != FIELD_DECL;
5254 next = DECL_CHAIN (next))
5257 /* If this is the last field in a struct type or a field in a
5258 union type do not warn. */
5263 low_bound = array_ref_low_bound (ref);
5264 up_bound_p1 = int_const_binop (PLUS_EXPR, up_bound, integer_one_node);
5266 if (TREE_CODE (low_sub) == SSA_NAME)
5268 vr = get_value_range (low_sub);
5269 if (vr->type == VR_RANGE || vr->type == VR_ANTI_RANGE)
5271 low_sub = vr->type == VR_RANGE ? vr->max : vr->min;
5272 up_sub = vr->type == VR_RANGE ? vr->min : vr->max;
5276 if (vr && vr->type == VR_ANTI_RANGE)
5278 if (TREE_CODE (up_sub) == INTEGER_CST
5279 && tree_int_cst_lt (up_bound, up_sub)
5280 && TREE_CODE (low_sub) == INTEGER_CST
5281 && tree_int_cst_lt (low_sub, low_bound))
5283 warning_at (location, OPT_Warray_bounds,
5284 "array subscript is outside array bounds");
5285 TREE_NO_WARNING (ref) = 1;
5288 else if (TREE_CODE (up_sub) == INTEGER_CST
5289 && (ignore_off_by_one
5290 ? (tree_int_cst_lt (up_bound, up_sub)
5291 && !tree_int_cst_equal (up_bound_p1, up_sub))
5292 : (tree_int_cst_lt (up_bound, up_sub)
5293 || tree_int_cst_equal (up_bound_p1, up_sub))))
5295 warning_at (location, OPT_Warray_bounds,
5296 "array subscript is above array bounds");
5297 TREE_NO_WARNING (ref) = 1;
5299 else if (TREE_CODE (low_sub) == INTEGER_CST
5300 && tree_int_cst_lt (low_sub, low_bound))
5302 warning_at (location, OPT_Warray_bounds,
5303 "array subscript is below array bounds");
5304 TREE_NO_WARNING (ref) = 1;
5308 /* Searches if the expr T, located at LOCATION computes
5309 address of an ARRAY_REF, and call check_array_ref on it. */
5312 search_for_addr_array (tree t, location_t location)
5314 while (TREE_CODE (t) == SSA_NAME)
5316 gimple g = SSA_NAME_DEF_STMT (t);
5318 if (gimple_code (g) != GIMPLE_ASSIGN)
5321 if (get_gimple_rhs_class (gimple_assign_rhs_code (g))
5322 != GIMPLE_SINGLE_RHS)
5325 t = gimple_assign_rhs1 (g);
5329 /* We are only interested in addresses of ARRAY_REF's. */
5330 if (TREE_CODE (t) != ADDR_EXPR)
5333 /* Check each ARRAY_REFs in the reference chain. */
5336 if (TREE_CODE (t) == ARRAY_REF)
5337 check_array_ref (location, t, true /*ignore_off_by_one*/);
5339 t = TREE_OPERAND (t, 0);
5341 while (handled_component_p (t));
5343 if (TREE_CODE (t) == MEM_REF
5344 && TREE_CODE (TREE_OPERAND (t, 0)) == ADDR_EXPR
5345 && !TREE_NO_WARNING (t))
5347 tree tem = TREE_OPERAND (TREE_OPERAND (t, 0), 0);
5348 tree low_bound, up_bound, el_sz;
5350 if (TREE_CODE (TREE_TYPE (tem)) != ARRAY_TYPE
5351 || TREE_CODE (TREE_TYPE (TREE_TYPE (tem))) == ARRAY_TYPE
5352 || !TYPE_DOMAIN (TREE_TYPE (tem)))
5355 low_bound = TYPE_MIN_VALUE (TYPE_DOMAIN (TREE_TYPE (tem)));
5356 up_bound = TYPE_MAX_VALUE (TYPE_DOMAIN (TREE_TYPE (tem)));
5357 el_sz = TYPE_SIZE_UNIT (TREE_TYPE (TREE_TYPE (tem)));
5359 || TREE_CODE (low_bound) != INTEGER_CST
5361 || TREE_CODE (up_bound) != INTEGER_CST
5363 || TREE_CODE (el_sz) != INTEGER_CST)
5366 idx = mem_ref_offset (t);
5367 idx = double_int_sdiv (idx, tree_to_double_int (el_sz), TRUNC_DIV_EXPR);
5368 if (double_int_scmp (idx, double_int_zero) < 0)
5370 warning_at (location, OPT_Warray_bounds,
5371 "array subscript is below array bounds");
5372 TREE_NO_WARNING (t) = 1;
5374 else if (double_int_scmp (idx,
5377 (tree_to_double_int (up_bound),
5379 (tree_to_double_int (low_bound))),
5380 double_int_one)) > 0)
5382 warning_at (location, OPT_Warray_bounds,
5383 "array subscript is above array bounds");
5384 TREE_NO_WARNING (t) = 1;
5389 /* walk_tree() callback that checks if *TP is
5390 an ARRAY_REF inside an ADDR_EXPR (in which an array
5391 subscript one outside the valid range is allowed). Call
5392 check_array_ref for each ARRAY_REF found. The location is
5396 check_array_bounds (tree *tp, int *walk_subtree, void *data)
5399 struct walk_stmt_info *wi = (struct walk_stmt_info *) data;
5400 location_t location;
5402 if (EXPR_HAS_LOCATION (t))
5403 location = EXPR_LOCATION (t);
5406 location_t *locp = (location_t *) wi->info;
5410 *walk_subtree = TRUE;
5412 if (TREE_CODE (t) == ARRAY_REF)
5413 check_array_ref (location, t, false /*ignore_off_by_one*/);
5415 if (TREE_CODE (t) == MEM_REF
5416 || (TREE_CODE (t) == RETURN_EXPR && TREE_OPERAND (t, 0)))
5417 search_for_addr_array (TREE_OPERAND (t, 0), location);
5419 if (TREE_CODE (t) == ADDR_EXPR)
5420 *walk_subtree = FALSE;
5425 /* Walk over all statements of all reachable BBs and call check_array_bounds
5429 check_all_array_refs (void)
5432 gimple_stmt_iterator si;
5438 bool executable = false;
5440 /* Skip blocks that were found to be unreachable. */
5441 FOR_EACH_EDGE (e, ei, bb->preds)
5442 executable |= !!(e->flags & EDGE_EXECUTABLE);
5446 for (si = gsi_start_bb (bb); !gsi_end_p (si); gsi_next (&si))
5448 gimple stmt = gsi_stmt (si);
5449 struct walk_stmt_info wi;
5450 if (!gimple_has_location (stmt))
5453 if (is_gimple_call (stmt))
5456 size_t n = gimple_call_num_args (stmt);
5457 for (i = 0; i < n; i++)
5459 tree arg = gimple_call_arg (stmt, i);
5460 search_for_addr_array (arg, gimple_location (stmt));
5465 memset (&wi, 0, sizeof (wi));
5466 wi.info = CONST_CAST (void *, (const void *)
5467 gimple_location_ptr (stmt));
5469 walk_gimple_op (gsi_stmt (si),
5477 /* Convert range assertion expressions into the implied copies and
5478 copy propagate away the copies. Doing the trivial copy propagation
5479 here avoids the need to run the full copy propagation pass after
5482 FIXME, this will eventually lead to copy propagation removing the
5483 names that had useful range information attached to them. For
5484 instance, if we had the assertion N_i = ASSERT_EXPR <N_j, N_j > 3>,
5485 then N_i will have the range [3, +INF].
5487 However, by converting the assertion into the implied copy
5488 operation N_i = N_j, we will then copy-propagate N_j into the uses
5489 of N_i and lose the range information. We may want to hold on to
5490 ASSERT_EXPRs a little while longer as the ranges could be used in
5491 things like jump threading.
5493 The problem with keeping ASSERT_EXPRs around is that passes after
5494 VRP need to handle them appropriately.
5496 Another approach would be to make the range information a first
5497 class property of the SSA_NAME so that it can be queried from
5498 any pass. This is made somewhat more complex by the need for
5499 multiple ranges to be associated with one SSA_NAME. */
5502 remove_range_assertions (void)
5505 gimple_stmt_iterator si;
5507 /* Note that the BSI iterator bump happens at the bottom of the
5508 loop and no bump is necessary if we're removing the statement
5509 referenced by the current BSI. */
5511 for (si = gsi_start_bb (bb); !gsi_end_p (si);)
5513 gimple stmt = gsi_stmt (si);
5516 if (is_gimple_assign (stmt)
5517 && gimple_assign_rhs_code (stmt) == ASSERT_EXPR)
5519 tree rhs = gimple_assign_rhs1 (stmt);
5521 tree cond = fold (ASSERT_EXPR_COND (rhs));
5522 use_operand_p use_p;
5523 imm_use_iterator iter;
5525 gcc_assert (cond != boolean_false_node);
5527 /* Propagate the RHS into every use of the LHS. */
5528 var = ASSERT_EXPR_VAR (rhs);
5529 FOR_EACH_IMM_USE_STMT (use_stmt, iter,
5530 gimple_assign_lhs (stmt))
5531 FOR_EACH_IMM_USE_ON_STMT (use_p, iter)
5533 SET_USE (use_p, var);
5534 gcc_assert (TREE_CODE (var) == SSA_NAME);
5537 /* And finally, remove the copy, it is not needed. */
5538 gsi_remove (&si, true);
5539 release_defs (stmt);
5547 /* Return true if STMT is interesting for VRP. */
5550 stmt_interesting_for_vrp (gimple stmt)
5552 if (gimple_code (stmt) == GIMPLE_PHI
5553 && is_gimple_reg (gimple_phi_result (stmt))
5554 && (INTEGRAL_TYPE_P (TREE_TYPE (gimple_phi_result (stmt)))
5555 || POINTER_TYPE_P (TREE_TYPE (gimple_phi_result (stmt)))))
5557 else if (is_gimple_assign (stmt) || is_gimple_call (stmt))
5559 tree lhs = gimple_get_lhs (stmt);
5561 /* In general, assignments with virtual operands are not useful
5562 for deriving ranges, with the obvious exception of calls to
5563 builtin functions. */
5564 if (lhs && TREE_CODE (lhs) == SSA_NAME
5565 && (INTEGRAL_TYPE_P (TREE_TYPE (lhs))
5566 || POINTER_TYPE_P (TREE_TYPE (lhs)))
5567 && ((is_gimple_call (stmt)
5568 && gimple_call_fndecl (stmt) != NULL_TREE
5569 && DECL_BUILT_IN (gimple_call_fndecl (stmt)))
5570 || !gimple_vuse (stmt)))
5573 else if (gimple_code (stmt) == GIMPLE_COND
5574 || gimple_code (stmt) == GIMPLE_SWITCH)
5581 /* Initialize local data structures for VRP. */
5584 vrp_initialize (void)
5588 values_propagated = false;
5589 num_vr_values = num_ssa_names;
5590 vr_value = XCNEWVEC (value_range_t *, num_vr_values);
5591 vr_phi_edge_counts = XCNEWVEC (int, num_ssa_names);
5595 gimple_stmt_iterator si;
5597 for (si = gsi_start_phis (bb); !gsi_end_p (si); gsi_next (&si))
5599 gimple phi = gsi_stmt (si);
5600 if (!stmt_interesting_for_vrp (phi))
5602 tree lhs = PHI_RESULT (phi);
5603 set_value_range_to_varying (get_value_range (lhs));
5604 prop_set_simulate_again (phi, false);
5607 prop_set_simulate_again (phi, true);
5610 for (si = gsi_start_bb (bb); !gsi_end_p (si); gsi_next (&si))
5612 gimple stmt = gsi_stmt (si);
5614 /* If the statement is a control insn, then we do not
5615 want to avoid simulating the statement once. Failure
5616 to do so means that those edges will never get added. */
5617 if (stmt_ends_bb_p (stmt))
5618 prop_set_simulate_again (stmt, true);
5619 else if (!stmt_interesting_for_vrp (stmt))
5623 FOR_EACH_SSA_TREE_OPERAND (def, stmt, i, SSA_OP_DEF)
5624 set_value_range_to_varying (get_value_range (def));
5625 prop_set_simulate_again (stmt, false);
5628 prop_set_simulate_again (stmt, true);
5633 /* Return the singleton value-range for NAME or NAME. */
5636 vrp_valueize (tree name)
5638 if (TREE_CODE (name) == SSA_NAME)
5640 value_range_t *vr = get_value_range (name);
5641 if (vr->type == VR_RANGE
5642 && (vr->min == vr->max
5643 || operand_equal_p (vr->min, vr->max, 0)))
5649 /* Visit assignment STMT. If it produces an interesting range, record
5650 the SSA name in *OUTPUT_P. */
5652 static enum ssa_prop_result
5653 vrp_visit_assignment_or_call (gimple stmt, tree *output_p)
5657 enum gimple_code code = gimple_code (stmt);
5658 lhs = gimple_get_lhs (stmt);
5660 /* We only keep track of ranges in integral and pointer types. */
5661 if (TREE_CODE (lhs) == SSA_NAME
5662 && ((INTEGRAL_TYPE_P (TREE_TYPE (lhs))
5663 /* It is valid to have NULL MIN/MAX values on a type. See
5664 build_range_type. */
5665 && TYPE_MIN_VALUE (TREE_TYPE (lhs))
5666 && TYPE_MAX_VALUE (TREE_TYPE (lhs)))
5667 || POINTER_TYPE_P (TREE_TYPE (lhs))))
5669 value_range_t new_vr = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
5671 /* Try folding the statement to a constant first. */
5672 tree tem = gimple_fold_stmt_to_constant (stmt, vrp_valueize);
5673 if (tem && !is_overflow_infinity (tem))
5674 set_value_range (&new_vr, VR_RANGE, tem, tem, NULL);
5675 /* Then dispatch to value-range extracting functions. */
5676 else if (code == GIMPLE_CALL)
5677 extract_range_basic (&new_vr, stmt);
5679 extract_range_from_assignment (&new_vr, stmt);
5681 if (update_value_range (lhs, &new_vr))
5685 if (dump_file && (dump_flags & TDF_DETAILS))
5687 fprintf (dump_file, "Found new range for ");
5688 print_generic_expr (dump_file, lhs, 0);
5689 fprintf (dump_file, ": ");
5690 dump_value_range (dump_file, &new_vr);
5691 fprintf (dump_file, "\n\n");
5694 if (new_vr.type == VR_VARYING)
5695 return SSA_PROP_VARYING;
5697 return SSA_PROP_INTERESTING;
5700 return SSA_PROP_NOT_INTERESTING;
5703 /* Every other statement produces no useful ranges. */
5704 FOR_EACH_SSA_TREE_OPERAND (def, stmt, iter, SSA_OP_DEF)
5705 set_value_range_to_varying (get_value_range (def));
5707 return SSA_PROP_VARYING;
5710 /* Helper that gets the value range of the SSA_NAME with version I
5711 or a symbolic range containing the SSA_NAME only if the value range
5712 is varying or undefined. */
5714 static inline value_range_t
5715 get_vr_for_comparison (int i)
5717 value_range_t vr = *get_value_range (ssa_name (i));
5719 /* If name N_i does not have a valid range, use N_i as its own
5720 range. This allows us to compare against names that may
5721 have N_i in their ranges. */
5722 if (vr.type == VR_VARYING || vr.type == VR_UNDEFINED)
5725 vr.min = ssa_name (i);
5726 vr.max = ssa_name (i);
5732 /* Compare all the value ranges for names equivalent to VAR with VAL
5733 using comparison code COMP. Return the same value returned by
5734 compare_range_with_value, including the setting of
5735 *STRICT_OVERFLOW_P. */
5738 compare_name_with_value (enum tree_code comp, tree var, tree val,
5739 bool *strict_overflow_p)
5745 int used_strict_overflow;
5747 value_range_t equiv_vr;
5749 /* Get the set of equivalences for VAR. */
5750 e = get_value_range (var)->equiv;
5752 /* Start at -1. Set it to 0 if we do a comparison without relying
5753 on overflow, or 1 if all comparisons rely on overflow. */
5754 used_strict_overflow = -1;
5756 /* Compare vars' value range with val. */
5757 equiv_vr = get_vr_for_comparison (SSA_NAME_VERSION (var));
5759 retval = compare_range_with_value (comp, &equiv_vr, val, &sop);
5761 used_strict_overflow = sop ? 1 : 0;
5763 /* If the equiv set is empty we have done all work we need to do. */
5767 && used_strict_overflow > 0)
5768 *strict_overflow_p = true;
5772 EXECUTE_IF_SET_IN_BITMAP (e, 0, i, bi)
5774 equiv_vr = get_vr_for_comparison (i);
5776 t = compare_range_with_value (comp, &equiv_vr, val, &sop);
5779 /* If we get different answers from different members
5780 of the equivalence set this check must be in a dead
5781 code region. Folding it to a trap representation
5782 would be correct here. For now just return don't-know. */
5792 used_strict_overflow = 0;
5793 else if (used_strict_overflow < 0)
5794 used_strict_overflow = 1;
5799 && used_strict_overflow > 0)
5800 *strict_overflow_p = true;
5806 /* Given a comparison code COMP and names N1 and N2, compare all the
5807 ranges equivalent to N1 against all the ranges equivalent to N2
5808 to determine the value of N1 COMP N2. Return the same value
5809 returned by compare_ranges. Set *STRICT_OVERFLOW_P to indicate
5810 whether we relied on an overflow infinity in the comparison. */
5814 compare_names (enum tree_code comp, tree n1, tree n2,
5815 bool *strict_overflow_p)
5819 bitmap_iterator bi1, bi2;
5821 int used_strict_overflow;
5822 static bitmap_obstack *s_obstack = NULL;
5823 static bitmap s_e1 = NULL, s_e2 = NULL;
5825 /* Compare the ranges of every name equivalent to N1 against the
5826 ranges of every name equivalent to N2. */
5827 e1 = get_value_range (n1)->equiv;
5828 e2 = get_value_range (n2)->equiv;
5830 /* Use the fake bitmaps if e1 or e2 are not available. */
5831 if (s_obstack == NULL)
5833 s_obstack = XNEW (bitmap_obstack);
5834 bitmap_obstack_initialize (s_obstack);
5835 s_e1 = BITMAP_ALLOC (s_obstack);
5836 s_e2 = BITMAP_ALLOC (s_obstack);
5843 /* Add N1 and N2 to their own set of equivalences to avoid
5844 duplicating the body of the loop just to check N1 and N2
5846 bitmap_set_bit (e1, SSA_NAME_VERSION (n1));
5847 bitmap_set_bit (e2, SSA_NAME_VERSION (n2));
5849 /* If the equivalence sets have a common intersection, then the two
5850 names can be compared without checking their ranges. */
5851 if (bitmap_intersect_p (e1, e2))
5853 bitmap_clear_bit (e1, SSA_NAME_VERSION (n1));
5854 bitmap_clear_bit (e2, SSA_NAME_VERSION (n2));
5856 return (comp == EQ_EXPR || comp == GE_EXPR || comp == LE_EXPR)
5858 : boolean_false_node;
5861 /* Start at -1. Set it to 0 if we do a comparison without relying
5862 on overflow, or 1 if all comparisons rely on overflow. */
5863 used_strict_overflow = -1;
5865 /* Otherwise, compare all the equivalent ranges. First, add N1 and
5866 N2 to their own set of equivalences to avoid duplicating the body
5867 of the loop just to check N1 and N2 ranges. */
5868 EXECUTE_IF_SET_IN_BITMAP (e1, 0, i1, bi1)
5870 value_range_t vr1 = get_vr_for_comparison (i1);
5872 t = retval = NULL_TREE;
5873 EXECUTE_IF_SET_IN_BITMAP (e2, 0, i2, bi2)
5877 value_range_t vr2 = get_vr_for_comparison (i2);
5879 t = compare_ranges (comp, &vr1, &vr2, &sop);
5882 /* If we get different answers from different members
5883 of the equivalence set this check must be in a dead
5884 code region. Folding it to a trap representation
5885 would be correct here. For now just return don't-know. */
5889 bitmap_clear_bit (e1, SSA_NAME_VERSION (n1));
5890 bitmap_clear_bit (e2, SSA_NAME_VERSION (n2));
5896 used_strict_overflow = 0;
5897 else if (used_strict_overflow < 0)
5898 used_strict_overflow = 1;
5904 bitmap_clear_bit (e1, SSA_NAME_VERSION (n1));
5905 bitmap_clear_bit (e2, SSA_NAME_VERSION (n2));
5906 if (used_strict_overflow > 0)
5907 *strict_overflow_p = true;
5912 /* None of the equivalent ranges are useful in computing this
5914 bitmap_clear_bit (e1, SSA_NAME_VERSION (n1));
5915 bitmap_clear_bit (e2, SSA_NAME_VERSION (n2));
5919 /* Helper function for vrp_evaluate_conditional_warnv. */
5922 vrp_evaluate_conditional_warnv_with_ops_using_ranges (enum tree_code code,
5924 bool * strict_overflow_p)
5926 value_range_t *vr0, *vr1;
5928 vr0 = (TREE_CODE (op0) == SSA_NAME) ? get_value_range (op0) : NULL;
5929 vr1 = (TREE_CODE (op1) == SSA_NAME) ? get_value_range (op1) : NULL;
5932 return compare_ranges (code, vr0, vr1, strict_overflow_p);
5933 else if (vr0 && vr1 == NULL)
5934 return compare_range_with_value (code, vr0, op1, strict_overflow_p);
5935 else if (vr0 == NULL && vr1)
5936 return (compare_range_with_value
5937 (swap_tree_comparison (code), vr1, op0, strict_overflow_p));
5941 /* Helper function for vrp_evaluate_conditional_warnv. */
5944 vrp_evaluate_conditional_warnv_with_ops (enum tree_code code, tree op0,
5945 tree op1, bool use_equiv_p,
5946 bool *strict_overflow_p, bool *only_ranges)
5950 *only_ranges = true;
5952 /* We only deal with integral and pointer types. */
5953 if (!INTEGRAL_TYPE_P (TREE_TYPE (op0))
5954 && !POINTER_TYPE_P (TREE_TYPE (op0)))
5960 && (ret = vrp_evaluate_conditional_warnv_with_ops_using_ranges
5961 (code, op0, op1, strict_overflow_p)))
5963 *only_ranges = false;
5964 if (TREE_CODE (op0) == SSA_NAME && TREE_CODE (op1) == SSA_NAME)
5965 return compare_names (code, op0, op1, strict_overflow_p);
5966 else if (TREE_CODE (op0) == SSA_NAME)
5967 return compare_name_with_value (code, op0, op1, strict_overflow_p);
5968 else if (TREE_CODE (op1) == SSA_NAME)
5969 return (compare_name_with_value
5970 (swap_tree_comparison (code), op1, op0, strict_overflow_p));
5973 return vrp_evaluate_conditional_warnv_with_ops_using_ranges (code, op0, op1,
5978 /* Given (CODE OP0 OP1) within STMT, try to simplify it based on value range
5979 information. Return NULL if the conditional can not be evaluated.
5980 The ranges of all the names equivalent with the operands in COND
5981 will be used when trying to compute the value. If the result is
5982 based on undefined signed overflow, issue a warning if
5986 vrp_evaluate_conditional (enum tree_code code, tree op0, tree op1, gimple stmt)
5992 /* Some passes and foldings leak constants with overflow flag set
5993 into the IL. Avoid doing wrong things with these and bail out. */
5994 if ((TREE_CODE (op0) == INTEGER_CST
5995 && TREE_OVERFLOW (op0))
5996 || (TREE_CODE (op1) == INTEGER_CST
5997 && TREE_OVERFLOW (op1)))
6001 ret = vrp_evaluate_conditional_warnv_with_ops (code, op0, op1, true, &sop,
6006 enum warn_strict_overflow_code wc;
6007 const char* warnmsg;
6009 if (is_gimple_min_invariant (ret))
6011 wc = WARN_STRICT_OVERFLOW_CONDITIONAL;
6012 warnmsg = G_("assuming signed overflow does not occur when "
6013 "simplifying conditional to constant");
6017 wc = WARN_STRICT_OVERFLOW_COMPARISON;
6018 warnmsg = G_("assuming signed overflow does not occur when "
6019 "simplifying conditional");
6022 if (issue_strict_overflow_warning (wc))
6024 location_t location;
6026 if (!gimple_has_location (stmt))
6027 location = input_location;
6029 location = gimple_location (stmt);
6030 warning_at (location, OPT_Wstrict_overflow, "%s", warnmsg);
6034 if (warn_type_limits
6035 && ret && only_ranges
6036 && TREE_CODE_CLASS (code) == tcc_comparison
6037 && TREE_CODE (op0) == SSA_NAME)
6039 /* If the comparison is being folded and the operand on the LHS
6040 is being compared against a constant value that is outside of
6041 the natural range of OP0's type, then the predicate will
6042 always fold regardless of the value of OP0. If -Wtype-limits
6043 was specified, emit a warning. */
6044 tree type = TREE_TYPE (op0);
6045 value_range_t *vr0 = get_value_range (op0);
6047 if (vr0->type != VR_VARYING
6048 && INTEGRAL_TYPE_P (type)
6049 && vrp_val_is_min (vr0->min)
6050 && vrp_val_is_max (vr0->max)
6051 && is_gimple_min_invariant (op1))
6053 location_t location;
6055 if (!gimple_has_location (stmt))
6056 location = input_location;
6058 location = gimple_location (stmt);
6060 warning_at (location, OPT_Wtype_limits,
6062 ? G_("comparison always false "
6063 "due to limited range of data type")
6064 : G_("comparison always true "
6065 "due to limited range of data type"));
6073 /* Visit conditional statement STMT. If we can determine which edge
6074 will be taken out of STMT's basic block, record it in
6075 *TAKEN_EDGE_P and return SSA_PROP_INTERESTING. Otherwise, return
6076 SSA_PROP_VARYING. */
6078 static enum ssa_prop_result
6079 vrp_visit_cond_stmt (gimple stmt, edge *taken_edge_p)
6084 *taken_edge_p = NULL;
6086 if (dump_file && (dump_flags & TDF_DETAILS))
6091 fprintf (dump_file, "\nVisiting conditional with predicate: ");
6092 print_gimple_stmt (dump_file, stmt, 0, 0);
6093 fprintf (dump_file, "\nWith known ranges\n");
6095 FOR_EACH_SSA_TREE_OPERAND (use, stmt, i, SSA_OP_USE)
6097 fprintf (dump_file, "\t");
6098 print_generic_expr (dump_file, use, 0);
6099 fprintf (dump_file, ": ");
6100 dump_value_range (dump_file, vr_value[SSA_NAME_VERSION (use)]);
6103 fprintf (dump_file, "\n");
6106 /* Compute the value of the predicate COND by checking the known
6107 ranges of each of its operands.
6109 Note that we cannot evaluate all the equivalent ranges here
6110 because those ranges may not yet be final and with the current
6111 propagation strategy, we cannot determine when the value ranges
6112 of the names in the equivalence set have changed.
6114 For instance, given the following code fragment
6118 i_14 = ASSERT_EXPR <i_5, i_5 != 0>
6122 Assume that on the first visit to i_14, i_5 has the temporary
6123 range [8, 8] because the second argument to the PHI function is
6124 not yet executable. We derive the range ~[0, 0] for i_14 and the
6125 equivalence set { i_5 }. So, when we visit 'if (i_14 == 1)' for
6126 the first time, since i_14 is equivalent to the range [8, 8], we
6127 determine that the predicate is always false.
6129 On the next round of propagation, i_13 is determined to be
6130 VARYING, which causes i_5 to drop down to VARYING. So, another
6131 visit to i_14 is scheduled. In this second visit, we compute the
6132 exact same range and equivalence set for i_14, namely ~[0, 0] and
6133 { i_5 }. But we did not have the previous range for i_5
6134 registered, so vrp_visit_assignment thinks that the range for
6135 i_14 has not changed. Therefore, the predicate 'if (i_14 == 1)'
6136 is not visited again, which stops propagation from visiting
6137 statements in the THEN clause of that if().
6139 To properly fix this we would need to keep the previous range
6140 value for the names in the equivalence set. This way we would've
6141 discovered that from one visit to the other i_5 changed from
6142 range [8, 8] to VR_VARYING.
6144 However, fixing this apparent limitation may not be worth the
6145 additional checking. Testing on several code bases (GCC, DLV,
6146 MICO, TRAMP3D and SPEC2000) showed that doing this results in
6147 4 more predicates folded in SPEC. */
6150 val = vrp_evaluate_conditional_warnv_with_ops (gimple_cond_code (stmt),
6151 gimple_cond_lhs (stmt),
6152 gimple_cond_rhs (stmt),
6157 *taken_edge_p = find_taken_edge (gimple_bb (stmt), val);
6160 if (dump_file && (dump_flags & TDF_DETAILS))
6162 "\nIgnoring predicate evaluation because "
6163 "it assumes that signed overflow is undefined");
6168 if (dump_file && (dump_flags & TDF_DETAILS))
6170 fprintf (dump_file, "\nPredicate evaluates to: ");
6171 if (val == NULL_TREE)
6172 fprintf (dump_file, "DON'T KNOW\n");
6174 print_generic_stmt (dump_file, val, 0);
6177 return (*taken_edge_p) ? SSA_PROP_INTERESTING : SSA_PROP_VARYING;
6180 /* Searches the case label vector VEC for the index *IDX of the CASE_LABEL
6181 that includes the value VAL. The search is restricted to the range
6182 [START_IDX, n - 1] where n is the size of VEC.
6184 If there is a CASE_LABEL for VAL, its index is placed in IDX and true is
6187 If there is no CASE_LABEL for VAL and there is one that is larger than VAL,
6188 it is placed in IDX and false is returned.
6190 If VAL is larger than any CASE_LABEL, n is placed on IDX and false is
6194 find_case_label_index (gimple stmt, size_t start_idx, tree val, size_t *idx)
6196 size_t n = gimple_switch_num_labels (stmt);
6199 /* Find case label for minimum of the value range or the next one.
6200 At each iteration we are searching in [low, high - 1]. */
6202 for (low = start_idx, high = n; high != low; )
6206 /* Note that i != high, so we never ask for n. */
6207 size_t i = (high + low) / 2;
6208 t = gimple_switch_label (stmt, i);
6210 /* Cache the result of comparing CASE_LOW and val. */
6211 cmp = tree_int_cst_compare (CASE_LOW (t), val);
6215 /* Ranges cannot be empty. */
6224 if (CASE_HIGH (t) != NULL
6225 && tree_int_cst_compare (CASE_HIGH (t), val) >= 0)
6237 /* Searches the case label vector VEC for the range of CASE_LABELs that is used
6238 for values between MIN and MAX. The first index is placed in MIN_IDX. The
6239 last index is placed in MAX_IDX. If the range of CASE_LABELs is empty
6240 then MAX_IDX < MIN_IDX.
6241 Returns true if the default label is not needed. */
6244 find_case_label_range (gimple stmt, tree min, tree max, size_t *min_idx,
6248 bool min_take_default = !find_case_label_index (stmt, 1, min, &i);
6249 bool max_take_default = !find_case_label_index (stmt, i, max, &j);
6253 && max_take_default)
6255 /* Only the default case label reached.
6256 Return an empty range. */
6263 bool take_default = min_take_default || max_take_default;
6267 if (max_take_default)
6270 /* If the case label range is continuous, we do not need
6271 the default case label. Verify that. */
6272 high = CASE_LOW (gimple_switch_label (stmt, i));
6273 if (CASE_HIGH (gimple_switch_label (stmt, i)))
6274 high = CASE_HIGH (gimple_switch_label (stmt, i));
6275 for (k = i + 1; k <= j; ++k)
6277 low = CASE_LOW (gimple_switch_label (stmt, k));
6278 if (!integer_onep (int_const_binop (MINUS_EXPR, low, high)))
6280 take_default = true;
6284 if (CASE_HIGH (gimple_switch_label (stmt, k)))
6285 high = CASE_HIGH (gimple_switch_label (stmt, k));
6290 return !take_default;
6294 /* Visit switch statement STMT. If we can determine which edge
6295 will be taken out of STMT's basic block, record it in
6296 *TAKEN_EDGE_P and return SSA_PROP_INTERESTING. Otherwise, return
6297 SSA_PROP_VARYING. */
6299 static enum ssa_prop_result
6300 vrp_visit_switch_stmt (gimple stmt, edge *taken_edge_p)
6304 size_t i = 0, j = 0;
6307 *taken_edge_p = NULL;
6308 op = gimple_switch_index (stmt);
6309 if (TREE_CODE (op) != SSA_NAME)
6310 return SSA_PROP_VARYING;
6312 vr = get_value_range (op);
6313 if (dump_file && (dump_flags & TDF_DETAILS))
6315 fprintf (dump_file, "\nVisiting switch expression with operand ");
6316 print_generic_expr (dump_file, op, 0);
6317 fprintf (dump_file, " with known range ");
6318 dump_value_range (dump_file, vr);
6319 fprintf (dump_file, "\n");
6322 if (vr->type != VR_RANGE
6323 || symbolic_range_p (vr))
6324 return SSA_PROP_VARYING;
6326 /* Find the single edge that is taken from the switch expression. */
6327 take_default = !find_case_label_range (stmt, vr->min, vr->max, &i, &j);
6329 /* Check if the range spans no CASE_LABEL. If so, we only reach the default
6333 gcc_assert (take_default);
6334 val = gimple_switch_default_label (stmt);
6338 /* Check if labels with index i to j and maybe the default label
6339 are all reaching the same label. */
6341 val = gimple_switch_label (stmt, i);
6343 && CASE_LABEL (gimple_switch_default_label (stmt))
6344 != CASE_LABEL (val))
6346 if (dump_file && (dump_flags & TDF_DETAILS))
6347 fprintf (dump_file, " not a single destination for this "
6349 return SSA_PROP_VARYING;
6351 for (++i; i <= j; ++i)
6353 if (CASE_LABEL (gimple_switch_label (stmt, i)) != CASE_LABEL (val))
6355 if (dump_file && (dump_flags & TDF_DETAILS))
6356 fprintf (dump_file, " not a single destination for this "
6358 return SSA_PROP_VARYING;
6363 *taken_edge_p = find_edge (gimple_bb (stmt),
6364 label_to_block (CASE_LABEL (val)));
6366 if (dump_file && (dump_flags & TDF_DETAILS))
6368 fprintf (dump_file, " will take edge to ");
6369 print_generic_stmt (dump_file, CASE_LABEL (val), 0);
6372 return SSA_PROP_INTERESTING;
6376 /* Evaluate statement STMT. If the statement produces a useful range,
6377 return SSA_PROP_INTERESTING and record the SSA name with the
6378 interesting range into *OUTPUT_P.
6380 If STMT is a conditional branch and we can determine its truth
6381 value, the taken edge is recorded in *TAKEN_EDGE_P.
6383 If STMT produces a varying value, return SSA_PROP_VARYING. */
6385 static enum ssa_prop_result
6386 vrp_visit_stmt (gimple stmt, edge *taken_edge_p, tree *output_p)
6391 if (dump_file && (dump_flags & TDF_DETAILS))
6393 fprintf (dump_file, "\nVisiting statement:\n");
6394 print_gimple_stmt (dump_file, stmt, 0, dump_flags);
6395 fprintf (dump_file, "\n");
6398 if (!stmt_interesting_for_vrp (stmt))
6399 gcc_assert (stmt_ends_bb_p (stmt));
6400 else if (is_gimple_assign (stmt) || is_gimple_call (stmt))
6402 /* In general, assignments with virtual operands are not useful
6403 for deriving ranges, with the obvious exception of calls to
6404 builtin functions. */
6405 if ((is_gimple_call (stmt)
6406 && gimple_call_fndecl (stmt) != NULL_TREE
6407 && DECL_BUILT_IN (gimple_call_fndecl (stmt)))
6408 || !gimple_vuse (stmt))
6409 return vrp_visit_assignment_or_call (stmt, output_p);
6411 else if (gimple_code (stmt) == GIMPLE_COND)
6412 return vrp_visit_cond_stmt (stmt, taken_edge_p);
6413 else if (gimple_code (stmt) == GIMPLE_SWITCH)
6414 return vrp_visit_switch_stmt (stmt, taken_edge_p);
6416 /* All other statements produce nothing of interest for VRP, so mark
6417 their outputs varying and prevent further simulation. */
6418 FOR_EACH_SSA_TREE_OPERAND (def, stmt, iter, SSA_OP_DEF)
6419 set_value_range_to_varying (get_value_range (def));
6421 return SSA_PROP_VARYING;
6425 /* Meet operation for value ranges. Given two value ranges VR0 and
6426 VR1, store in VR0 a range that contains both VR0 and VR1. This
6427 may not be the smallest possible such range. */
6430 vrp_meet (value_range_t *vr0, value_range_t *vr1)
6432 if (vr0->type == VR_UNDEFINED)
6434 /* Drop equivalences. See PR53465. */
6435 set_value_range (vr0, vr1->type, vr1->min, vr1->max, NULL);
6439 if (vr1->type == VR_UNDEFINED)
6441 /* VR0 already has the resulting range, just drop equivalences.
6444 bitmap_clear (vr0->equiv);
6448 if (vr0->type == VR_VARYING)
6450 /* Nothing to do. VR0 already has the resulting range. */
6454 if (vr1->type == VR_VARYING)
6456 set_value_range_to_varying (vr0);
6460 if (vr0->type == VR_RANGE && vr1->type == VR_RANGE)
6465 /* Compute the convex hull of the ranges. The lower limit of
6466 the new range is the minimum of the two ranges. If they
6467 cannot be compared, then give up. */
6468 cmp = compare_values (vr0->min, vr1->min);
6469 if (cmp == 0 || cmp == 1)
6476 /* Similarly, the upper limit of the new range is the maximum
6477 of the two ranges. If they cannot be compared, then
6479 cmp = compare_values (vr0->max, vr1->max);
6480 if (cmp == 0 || cmp == -1)
6487 /* Check for useless ranges. */
6488 if (INTEGRAL_TYPE_P (TREE_TYPE (min))
6489 && ((vrp_val_is_min (min) || is_overflow_infinity (min))
6490 && (vrp_val_is_max (max) || is_overflow_infinity (max))))
6493 /* The resulting set of equivalences is the intersection of
6495 if (vr0->equiv && vr1->equiv && vr0->equiv != vr1->equiv)
6496 bitmap_and_into (vr0->equiv, vr1->equiv);
6497 else if (vr0->equiv && !vr1->equiv)
6498 bitmap_clear (vr0->equiv);
6500 set_value_range (vr0, vr0->type, min, max, vr0->equiv);
6502 else if (vr0->type == VR_ANTI_RANGE && vr1->type == VR_ANTI_RANGE)
6504 /* Two anti-ranges meet only if their complements intersect.
6505 Only handle the case of identical ranges. */
6506 if (compare_values (vr0->min, vr1->min) == 0
6507 && compare_values (vr0->max, vr1->max) == 0
6508 && compare_values (vr0->min, vr0->max) == 0)
6510 /* The resulting set of equivalences is the intersection of
6512 if (vr0->equiv && vr1->equiv && vr0->equiv != vr1->equiv)
6513 bitmap_and_into (vr0->equiv, vr1->equiv);
6514 else if (vr0->equiv && !vr1->equiv)
6515 bitmap_clear (vr0->equiv);
6520 else if (vr0->type == VR_ANTI_RANGE || vr1->type == VR_ANTI_RANGE)
6522 /* For a numeric range [VAL1, VAL2] and an anti-range ~[VAL3, VAL4],
6523 only handle the case where the ranges have an empty intersection.
6524 The result of the meet operation is the anti-range. */
6525 if (!symbolic_range_p (vr0)
6526 && !symbolic_range_p (vr1)
6527 && !value_ranges_intersect_p (vr0, vr1))
6529 /* Copy most of VR1 into VR0. Don't copy VR1's equivalence
6530 set. We need to compute the intersection of the two
6531 equivalence sets. */
6532 if (vr1->type == VR_ANTI_RANGE)
6533 set_value_range (vr0, vr1->type, vr1->min, vr1->max, vr0->equiv);
6535 /* The resulting set of equivalences is the intersection of
6537 if (vr0->equiv && vr1->equiv && vr0->equiv != vr1->equiv)
6538 bitmap_and_into (vr0->equiv, vr1->equiv);
6539 else if (vr0->equiv && !vr1->equiv)
6540 bitmap_clear (vr0->equiv);
6551 /* Failed to find an efficient meet. Before giving up and setting
6552 the result to VARYING, see if we can at least derive a useful
6553 anti-range. FIXME, all this nonsense about distinguishing
6554 anti-ranges from ranges is necessary because of the odd
6555 semantics of range_includes_zero_p and friends. */
6556 if (!symbolic_range_p (vr0)
6557 && ((vr0->type == VR_RANGE
6558 && range_includes_zero_p (vr0->min, vr0->max) == 0)
6559 || (vr0->type == VR_ANTI_RANGE
6560 && range_includes_zero_p (vr0->min, vr0->max) == 1))
6561 && !symbolic_range_p (vr1)
6562 && ((vr1->type == VR_RANGE
6563 && range_includes_zero_p (vr1->min, vr1->max) == 0)
6564 || (vr1->type == VR_ANTI_RANGE
6565 && range_includes_zero_p (vr1->min, vr1->max) == 1)))
6567 set_value_range_to_nonnull (vr0, TREE_TYPE (vr0->min));
6569 /* Since this meet operation did not result from the meeting of
6570 two equivalent names, VR0 cannot have any equivalences. */
6572 bitmap_clear (vr0->equiv);
6575 set_value_range_to_varying (vr0);
6579 /* Visit all arguments for PHI node PHI that flow through executable
6580 edges. If a valid value range can be derived from all the incoming
6581 value ranges, set a new range for the LHS of PHI. */
6583 static enum ssa_prop_result
6584 vrp_visit_phi_node (gimple phi)
6587 tree lhs = PHI_RESULT (phi);
6588 value_range_t *lhs_vr = get_value_range (lhs);
6589 value_range_t vr_result = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
6591 int edges, old_edges;
6594 if (dump_file && (dump_flags & TDF_DETAILS))
6596 fprintf (dump_file, "\nVisiting PHI node: ");
6597 print_gimple_stmt (dump_file, phi, 0, dump_flags);
6601 for (i = 0; i < gimple_phi_num_args (phi); i++)
6603 edge e = gimple_phi_arg_edge (phi, i);
6605 if (dump_file && (dump_flags & TDF_DETAILS))
6608 "\n Argument #%d (%d -> %d %sexecutable)\n",
6609 (int) i, e->src->index, e->dest->index,
6610 (e->flags & EDGE_EXECUTABLE) ? "" : "not ");
6613 if (e->flags & EDGE_EXECUTABLE)
6615 tree arg = PHI_ARG_DEF (phi, i);
6616 value_range_t vr_arg;
6620 if (TREE_CODE (arg) == SSA_NAME)
6622 vr_arg = *(get_value_range (arg));
6623 /* Do not allow equivalences or symbolic ranges to leak in from
6624 backedges. That creates invalid equivalencies. */
6625 if (e->flags & EDGE_DFS_BACK
6626 && (vr_arg.type == VR_RANGE
6627 || vr_arg.type == VR_ANTI_RANGE))
6629 vr_arg.equiv = NULL;
6630 if (symbolic_range_p (&vr_arg))
6632 vr_arg.type = VR_VARYING;
6633 vr_arg.min = NULL_TREE;
6634 vr_arg.max = NULL_TREE;
6640 if (is_overflow_infinity (arg))
6642 arg = copy_node (arg);
6643 TREE_OVERFLOW (arg) = 0;
6646 vr_arg.type = VR_RANGE;
6649 vr_arg.equiv = NULL;
6652 if (dump_file && (dump_flags & TDF_DETAILS))
6654 fprintf (dump_file, "\t");
6655 print_generic_expr (dump_file, arg, dump_flags);
6656 fprintf (dump_file, "\n\tValue: ");
6657 dump_value_range (dump_file, &vr_arg);
6658 fprintf (dump_file, "\n");
6662 copy_value_range (&vr_result, &vr_arg);
6664 vrp_meet (&vr_result, &vr_arg);
6667 if (vr_result.type == VR_VARYING)
6672 if (vr_result.type == VR_VARYING)
6674 else if (vr_result.type == VR_UNDEFINED)
6677 old_edges = vr_phi_edge_counts[SSA_NAME_VERSION (lhs)];
6678 vr_phi_edge_counts[SSA_NAME_VERSION (lhs)] = edges;
6680 /* To prevent infinite iterations in the algorithm, derive ranges
6681 when the new value is slightly bigger or smaller than the
6682 previous one. We don't do this if we have seen a new executable
6683 edge; this helps us avoid an overflow infinity for conditionals
6684 which are not in a loop. */
6686 && gimple_phi_num_args (phi) > 1
6687 && edges == old_edges)
6689 int cmp_min = compare_values (lhs_vr->min, vr_result.min);
6690 int cmp_max = compare_values (lhs_vr->max, vr_result.max);
6692 /* For non VR_RANGE or for pointers fall back to varying if
6693 the range changed. */
6694 if ((lhs_vr->type != VR_RANGE || vr_result.type != VR_RANGE
6695 || POINTER_TYPE_P (TREE_TYPE (lhs)))
6696 && (cmp_min != 0 || cmp_max != 0))
6699 /* If the new minimum is smaller or larger than the previous
6700 one, go all the way to -INF. In the first case, to avoid
6701 iterating millions of times to reach -INF, and in the
6702 other case to avoid infinite bouncing between different
6704 if (cmp_min > 0 || cmp_min < 0)
6706 if (!needs_overflow_infinity (TREE_TYPE (vr_result.min))
6707 || !vrp_var_may_overflow (lhs, phi))
6708 vr_result.min = TYPE_MIN_VALUE (TREE_TYPE (vr_result.min));
6709 else if (supports_overflow_infinity (TREE_TYPE (vr_result.min)))
6711 negative_overflow_infinity (TREE_TYPE (vr_result.min));
6714 /* Similarly, if the new maximum is smaller or larger than
6715 the previous one, go all the way to +INF. */
6716 if (cmp_max < 0 || cmp_max > 0)
6718 if (!needs_overflow_infinity (TREE_TYPE (vr_result.max))
6719 || !vrp_var_may_overflow (lhs, phi))
6720 vr_result.max = TYPE_MAX_VALUE (TREE_TYPE (vr_result.max));
6721 else if (supports_overflow_infinity (TREE_TYPE (vr_result.max)))
6723 positive_overflow_infinity (TREE_TYPE (vr_result.max));
6726 /* If we dropped either bound to +-INF then if this is a loop
6727 PHI node SCEV may known more about its value-range. */
6728 if ((cmp_min > 0 || cmp_min < 0
6729 || cmp_max < 0 || cmp_max > 0)
6731 && (l = loop_containing_stmt (phi))
6732 && l->header == gimple_bb (phi))
6733 adjust_range_with_scev (&vr_result, l, phi, lhs);
6735 /* If we will end up with a (-INF, +INF) range, set it to
6736 VARYING. Same if the previous max value was invalid for
6737 the type and we end up with vr_result.min > vr_result.max. */
6738 if ((vrp_val_is_max (vr_result.max)
6739 && vrp_val_is_min (vr_result.min))
6740 || compare_values (vr_result.min,
6745 /* If the new range is different than the previous value, keep
6748 if (update_value_range (lhs, &vr_result))
6750 if (dump_file && (dump_flags & TDF_DETAILS))
6752 fprintf (dump_file, "Found new range for ");
6753 print_generic_expr (dump_file, lhs, 0);
6754 fprintf (dump_file, ": ");
6755 dump_value_range (dump_file, &vr_result);
6756 fprintf (dump_file, "\n\n");
6759 return SSA_PROP_INTERESTING;
6762 /* Nothing changed, don't add outgoing edges. */
6763 return SSA_PROP_NOT_INTERESTING;
6765 /* No match found. Set the LHS to VARYING. */
6767 set_value_range_to_varying (lhs_vr);
6768 return SSA_PROP_VARYING;
6771 /* Simplify boolean operations if the source is known
6772 to be already a boolean. */
6774 simplify_truth_ops_using_ranges (gimple_stmt_iterator *gsi, gimple stmt)
6776 enum tree_code rhs_code = gimple_assign_rhs_code (stmt);
6778 bool need_conversion;
6780 /* We handle only !=/== case here. */
6781 gcc_assert (rhs_code == EQ_EXPR || rhs_code == NE_EXPR);
6783 op0 = gimple_assign_rhs1 (stmt);
6784 if (!op_with_boolean_value_range_p (op0))
6787 op1 = gimple_assign_rhs2 (stmt);
6788 if (!op_with_boolean_value_range_p (op1))
6791 /* Reduce number of cases to handle to NE_EXPR. As there is no
6792 BIT_XNOR_EXPR we cannot replace A == B with a single statement. */
6793 if (rhs_code == EQ_EXPR)
6795 if (TREE_CODE (op1) == INTEGER_CST)
6796 op1 = int_const_binop (BIT_XOR_EXPR, op1, integer_one_node);
6801 lhs = gimple_assign_lhs (stmt);
6803 = !useless_type_conversion_p (TREE_TYPE (lhs), TREE_TYPE (op0));
6805 /* Make sure to not sign-extend a 1-bit 1 when converting the result. */
6807 && !TYPE_UNSIGNED (TREE_TYPE (op0))
6808 && TYPE_PRECISION (TREE_TYPE (op0)) == 1
6809 && TYPE_PRECISION (TREE_TYPE (lhs)) > 1)
6812 /* For A != 0 we can substitute A itself. */
6813 if (integer_zerop (op1))
6814 gimple_assign_set_rhs_with_ops (gsi,
6816 ? NOP_EXPR : TREE_CODE (op0),
6818 /* For A != B we substitute A ^ B. Either with conversion. */
6819 else if (need_conversion)
6822 tree tem = create_tmp_reg (TREE_TYPE (op0), NULL);
6823 newop = gimple_build_assign_with_ops (BIT_XOR_EXPR, tem, op0, op1);
6824 tem = make_ssa_name (tem, newop);
6825 gimple_assign_set_lhs (newop, tem);
6826 gsi_insert_before (gsi, newop, GSI_SAME_STMT);
6827 update_stmt (newop);
6828 gimple_assign_set_rhs_with_ops (gsi, NOP_EXPR, tem, NULL_TREE);
6832 gimple_assign_set_rhs_with_ops (gsi, BIT_XOR_EXPR, op0, op1);
6833 update_stmt (gsi_stmt (*gsi));
6838 /* Simplify a division or modulo operator to a right shift or
6839 bitwise and if the first operand is unsigned or is greater
6840 than zero and the second operand is an exact power of two. */
6843 simplify_div_or_mod_using_ranges (gimple stmt)
6845 enum tree_code rhs_code = gimple_assign_rhs_code (stmt);
6847 tree op0 = gimple_assign_rhs1 (stmt);
6848 tree op1 = gimple_assign_rhs2 (stmt);
6849 value_range_t *vr = get_value_range (gimple_assign_rhs1 (stmt));
6851 if (TYPE_UNSIGNED (TREE_TYPE (op0)))
6853 val = integer_one_node;
6859 val = compare_range_with_value (GE_EXPR, vr, integer_zero_node, &sop);
6863 && integer_onep (val)
6864 && issue_strict_overflow_warning (WARN_STRICT_OVERFLOW_MISC))
6866 location_t location;
6868 if (!gimple_has_location (stmt))
6869 location = input_location;
6871 location = gimple_location (stmt);
6872 warning_at (location, OPT_Wstrict_overflow,
6873 "assuming signed overflow does not occur when "
6874 "simplifying %</%> or %<%%%> to %<>>%> or %<&%>");
6878 if (val && integer_onep (val))
6882 if (rhs_code == TRUNC_DIV_EXPR)
6884 t = build_int_cst (integer_type_node, tree_log2 (op1));
6885 gimple_assign_set_rhs_code (stmt, RSHIFT_EXPR);
6886 gimple_assign_set_rhs1 (stmt, op0);
6887 gimple_assign_set_rhs2 (stmt, t);
6891 t = build_int_cst (TREE_TYPE (op1), 1);
6892 t = int_const_binop (MINUS_EXPR, op1, t);
6893 t = fold_convert (TREE_TYPE (op0), t);
6895 gimple_assign_set_rhs_code (stmt, BIT_AND_EXPR);
6896 gimple_assign_set_rhs1 (stmt, op0);
6897 gimple_assign_set_rhs2 (stmt, t);
6907 /* If the operand to an ABS_EXPR is >= 0, then eliminate the
6908 ABS_EXPR. If the operand is <= 0, then simplify the
6909 ABS_EXPR into a NEGATE_EXPR. */
6912 simplify_abs_using_ranges (gimple stmt)
6915 tree op = gimple_assign_rhs1 (stmt);
6916 tree type = TREE_TYPE (op);
6917 value_range_t *vr = get_value_range (op);
6919 if (TYPE_UNSIGNED (type))
6921 val = integer_zero_node;
6927 val = compare_range_with_value (LE_EXPR, vr, integer_zero_node, &sop);
6931 val = compare_range_with_value (GE_EXPR, vr, integer_zero_node,
6936 if (integer_zerop (val))
6937 val = integer_one_node;
6938 else if (integer_onep (val))
6939 val = integer_zero_node;
6944 && (integer_onep (val) || integer_zerop (val)))
6946 if (sop && issue_strict_overflow_warning (WARN_STRICT_OVERFLOW_MISC))
6948 location_t location;
6950 if (!gimple_has_location (stmt))
6951 location = input_location;
6953 location = gimple_location (stmt);
6954 warning_at (location, OPT_Wstrict_overflow,
6955 "assuming signed overflow does not occur when "
6956 "simplifying %<abs (X)%> to %<X%> or %<-X%>");
6959 gimple_assign_set_rhs1 (stmt, op);
6960 if (integer_onep (val))
6961 gimple_assign_set_rhs_code (stmt, NEGATE_EXPR);
6963 gimple_assign_set_rhs_code (stmt, SSA_NAME);
6972 /* Optimize away redundant BIT_AND_EXPR and BIT_IOR_EXPR.
6973 If all the bits that are being cleared by & are already
6974 known to be zero from VR, or all the bits that are being
6975 set by | are already known to be one from VR, the bit
6976 operation is redundant. */
6979 simplify_bit_ops_using_ranges (gimple_stmt_iterator *gsi, gimple stmt)
6981 tree op0 = gimple_assign_rhs1 (stmt);
6982 tree op1 = gimple_assign_rhs2 (stmt);
6983 tree op = NULL_TREE;
6984 value_range_t vr0 = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
6985 value_range_t vr1 = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
6986 double_int may_be_nonzero0, may_be_nonzero1;
6987 double_int must_be_nonzero0, must_be_nonzero1;
6990 if (TREE_CODE (op0) == SSA_NAME)
6991 vr0 = *(get_value_range (op0));
6992 else if (is_gimple_min_invariant (op0))
6993 set_value_range_to_value (&vr0, op0, NULL);
6997 if (TREE_CODE (op1) == SSA_NAME)
6998 vr1 = *(get_value_range (op1));
6999 else if (is_gimple_min_invariant (op1))
7000 set_value_range_to_value (&vr1, op1, NULL);
7004 if (!zero_nonzero_bits_from_vr (&vr0, &may_be_nonzero0, &must_be_nonzero0))
7006 if (!zero_nonzero_bits_from_vr (&vr1, &may_be_nonzero1, &must_be_nonzero1))
7009 switch (gimple_assign_rhs_code (stmt))
7012 mask = double_int_and_not (may_be_nonzero0, must_be_nonzero1);
7013 if (double_int_zero_p (mask))
7018 mask = double_int_and_not (may_be_nonzero1, must_be_nonzero0);
7019 if (double_int_zero_p (mask))
7026 mask = double_int_and_not (may_be_nonzero0, must_be_nonzero1);
7027 if (double_int_zero_p (mask))
7032 mask = double_int_and_not (may_be_nonzero1, must_be_nonzero0);
7033 if (double_int_zero_p (mask))
7043 if (op == NULL_TREE)
7046 gimple_assign_set_rhs_with_ops (gsi, TREE_CODE (op), op, NULL);
7047 update_stmt (gsi_stmt (*gsi));
7051 /* We are comparing trees OP0 and OP1 using COND_CODE. OP0 has
7052 a known value range VR.
7054 If there is one and only one value which will satisfy the
7055 conditional, then return that value. Else return NULL. */
7058 test_for_singularity (enum tree_code cond_code, tree op0,
7059 tree op1, value_range_t *vr)
7064 /* Extract minimum/maximum values which satisfy the
7065 the conditional as it was written. */
7066 if (cond_code == LE_EXPR || cond_code == LT_EXPR)
7068 /* This should not be negative infinity; there is no overflow
7070 min = TYPE_MIN_VALUE (TREE_TYPE (op0));
7073 if (cond_code == LT_EXPR && !is_overflow_infinity (max))
7075 tree one = build_int_cst (TREE_TYPE (op0), 1);
7076 max = fold_build2 (MINUS_EXPR, TREE_TYPE (op0), max, one);
7078 TREE_NO_WARNING (max) = 1;
7081 else if (cond_code == GE_EXPR || cond_code == GT_EXPR)
7083 /* This should not be positive infinity; there is no overflow
7085 max = TYPE_MAX_VALUE (TREE_TYPE (op0));
7088 if (cond_code == GT_EXPR && !is_overflow_infinity (min))
7090 tree one = build_int_cst (TREE_TYPE (op0), 1);
7091 min = fold_build2 (PLUS_EXPR, TREE_TYPE (op0), min, one);
7093 TREE_NO_WARNING (min) = 1;
7097 /* Now refine the minimum and maximum values using any
7098 value range information we have for op0. */
7101 if (compare_values (vr->min, min) == 1)
7103 if (compare_values (vr->max, max) == -1)
7106 /* If the new min/max values have converged to a single value,
7107 then there is only one value which can satisfy the condition,
7108 return that value. */
7109 if (operand_equal_p (min, max, 0) && is_gimple_min_invariant (min))
7115 /* Simplify a conditional using a relational operator to an equality
7116 test if the range information indicates only one value can satisfy
7117 the original conditional. */
7120 simplify_cond_using_ranges (gimple stmt)
7122 tree op0 = gimple_cond_lhs (stmt);
7123 tree op1 = gimple_cond_rhs (stmt);
7124 enum tree_code cond_code = gimple_cond_code (stmt);
7126 if (cond_code != NE_EXPR
7127 && cond_code != EQ_EXPR
7128 && TREE_CODE (op0) == SSA_NAME
7129 && INTEGRAL_TYPE_P (TREE_TYPE (op0))
7130 && is_gimple_min_invariant (op1))
7132 value_range_t *vr = get_value_range (op0);
7134 /* If we have range information for OP0, then we might be
7135 able to simplify this conditional. */
7136 if (vr->type == VR_RANGE)
7138 tree new_tree = test_for_singularity (cond_code, op0, op1, vr);
7144 fprintf (dump_file, "Simplified relational ");
7145 print_gimple_stmt (dump_file, stmt, 0, 0);
7146 fprintf (dump_file, " into ");
7149 gimple_cond_set_code (stmt, EQ_EXPR);
7150 gimple_cond_set_lhs (stmt, op0);
7151 gimple_cond_set_rhs (stmt, new_tree);
7157 print_gimple_stmt (dump_file, stmt, 0, 0);
7158 fprintf (dump_file, "\n");
7164 /* Try again after inverting the condition. We only deal
7165 with integral types here, so no need to worry about
7166 issues with inverting FP comparisons. */
7167 cond_code = invert_tree_comparison (cond_code, false);
7168 new_tree = test_for_singularity (cond_code, op0, op1, vr);
7174 fprintf (dump_file, "Simplified relational ");
7175 print_gimple_stmt (dump_file, stmt, 0, 0);
7176 fprintf (dump_file, " into ");
7179 gimple_cond_set_code (stmt, NE_EXPR);
7180 gimple_cond_set_lhs (stmt, op0);
7181 gimple_cond_set_rhs (stmt, new_tree);
7187 print_gimple_stmt (dump_file, stmt, 0, 0);
7188 fprintf (dump_file, "\n");
7199 /* Simplify a switch statement using the value range of the switch
7203 simplify_switch_using_ranges (gimple stmt)
7205 tree op = gimple_switch_index (stmt);
7210 size_t i = 0, j = 0, n, n2;
7214 if (TREE_CODE (op) == SSA_NAME)
7216 vr = get_value_range (op);
7218 /* We can only handle integer ranges. */
7219 if (vr->type != VR_RANGE
7220 || symbolic_range_p (vr))
7223 /* Find case label for min/max of the value range. */
7224 take_default = !find_case_label_range (stmt, vr->min, vr->max, &i, &j);
7226 else if (TREE_CODE (op) == INTEGER_CST)
7228 take_default = !find_case_label_index (stmt, 1, op, &i);
7242 n = gimple_switch_num_labels (stmt);
7244 /* Bail out if this is just all edges taken. */
7250 /* Build a new vector of taken case labels. */
7251 vec2 = make_tree_vec (j - i + 1 + (int)take_default);
7254 /* Add the default edge, if necessary. */
7256 TREE_VEC_ELT (vec2, n2++) = gimple_switch_default_label (stmt);
7258 for (; i <= j; ++i, ++n2)
7259 TREE_VEC_ELT (vec2, n2) = gimple_switch_label (stmt, i);
7261 /* Mark needed edges. */
7262 for (i = 0; i < n2; ++i)
7264 e = find_edge (gimple_bb (stmt),
7265 label_to_block (CASE_LABEL (TREE_VEC_ELT (vec2, i))));
7266 e->aux = (void *)-1;
7269 /* Queue not needed edges for later removal. */
7270 FOR_EACH_EDGE (e, ei, gimple_bb (stmt)->succs)
7272 if (e->aux == (void *)-1)
7278 if (dump_file && (dump_flags & TDF_DETAILS))
7280 fprintf (dump_file, "removing unreachable case label\n");
7282 VEC_safe_push (edge, heap, to_remove_edges, e);
7283 e->flags &= ~EDGE_EXECUTABLE;
7286 /* And queue an update for the stmt. */
7289 VEC_safe_push (switch_update, heap, to_update_switch_stmts, &su);
7293 /* Simplify an integral conversion from an SSA name in STMT. */
7296 simplify_conversion_using_ranges (gimple stmt)
7298 tree innerop, middleop, finaltype;
7300 value_range_t *innervr;
7301 bool inner_unsigned_p, middle_unsigned_p, final_unsigned_p;
7302 unsigned inner_prec, middle_prec, final_prec;
7303 double_int innermin, innermed, innermax, middlemin, middlemed, middlemax;
7305 finaltype = TREE_TYPE (gimple_assign_lhs (stmt));
7306 if (!INTEGRAL_TYPE_P (finaltype))
7308 middleop = gimple_assign_rhs1 (stmt);
7309 def_stmt = SSA_NAME_DEF_STMT (middleop);
7310 if (!is_gimple_assign (def_stmt)
7311 || !CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (def_stmt)))
7313 innerop = gimple_assign_rhs1 (def_stmt);
7314 if (TREE_CODE (innerop) != SSA_NAME)
7317 /* Get the value-range of the inner operand. */
7318 innervr = get_value_range (innerop);
7319 if (innervr->type != VR_RANGE
7320 || TREE_CODE (innervr->min) != INTEGER_CST
7321 || TREE_CODE (innervr->max) != INTEGER_CST)
7324 /* Simulate the conversion chain to check if the result is equal if
7325 the middle conversion is removed. */
7326 innermin = tree_to_double_int (innervr->min);
7327 innermax = tree_to_double_int (innervr->max);
7329 inner_prec = TYPE_PRECISION (TREE_TYPE (innerop));
7330 middle_prec = TYPE_PRECISION (TREE_TYPE (middleop));
7331 final_prec = TYPE_PRECISION (finaltype);
7333 /* If the first conversion is not injective, the second must not
7335 if (double_int_cmp (double_int_sub (innermax, innermin),
7336 double_int_mask (middle_prec), true) > 0
7337 && middle_prec < final_prec)
7339 /* We also want a medium value so that we can track the effect that
7340 narrowing conversions with sign change have. */
7341 inner_unsigned_p = TYPE_UNSIGNED (TREE_TYPE (innerop));
7342 if (inner_unsigned_p)
7343 innermed = double_int_rshift (double_int_mask (inner_prec),
7344 1, inner_prec, false);
7346 innermed = double_int_zero;
7347 if (double_int_cmp (innermin, innermed, inner_unsigned_p) >= 0
7348 || double_int_cmp (innermed, innermax, inner_unsigned_p) >= 0)
7349 innermed = innermin;
7351 middle_unsigned_p = TYPE_UNSIGNED (TREE_TYPE (middleop));
7352 middlemin = double_int_ext (innermin, middle_prec, middle_unsigned_p);
7353 middlemed = double_int_ext (innermed, middle_prec, middle_unsigned_p);
7354 middlemax = double_int_ext (innermax, middle_prec, middle_unsigned_p);
7356 /* Require that the final conversion applied to both the original
7357 and the intermediate range produces the same result. */
7358 final_unsigned_p = TYPE_UNSIGNED (finaltype);
7359 if (!double_int_equal_p (double_int_ext (middlemin,
7360 final_prec, final_unsigned_p),
7361 double_int_ext (innermin,
7362 final_prec, final_unsigned_p))
7363 || !double_int_equal_p (double_int_ext (middlemed,
7364 final_prec, final_unsigned_p),
7365 double_int_ext (innermed,
7366 final_prec, final_unsigned_p))
7367 || !double_int_equal_p (double_int_ext (middlemax,
7368 final_prec, final_unsigned_p),
7369 double_int_ext (innermax,
7370 final_prec, final_unsigned_p)))
7373 gimple_assign_set_rhs1 (stmt, innerop);
7378 /* Return whether the value range *VR fits in an integer type specified
7379 by PRECISION and UNSIGNED_P. */
7382 range_fits_type_p (value_range_t *vr, unsigned precision, bool unsigned_p)
7385 unsigned src_precision;
7388 /* We can only handle integral and pointer types. */
7389 src_type = TREE_TYPE (vr->min);
7390 if (!INTEGRAL_TYPE_P (src_type)
7391 && !POINTER_TYPE_P (src_type))
7394 /* An extension is always fine, so is an identity transform. */
7395 src_precision = TYPE_PRECISION (TREE_TYPE (vr->min));
7396 if (src_precision < precision
7397 || (src_precision == precision
7398 && TYPE_UNSIGNED (src_type) == unsigned_p))
7401 /* Now we can only handle ranges with constant bounds. */
7402 if (vr->type != VR_RANGE
7403 || TREE_CODE (vr->min) != INTEGER_CST
7404 || TREE_CODE (vr->max) != INTEGER_CST)
7407 /* For precision-preserving sign-changes the MSB of the double-int
7409 if (src_precision == precision
7410 && (TREE_INT_CST_HIGH (vr->min) | TREE_INT_CST_HIGH (vr->max)) < 0)
7413 /* Then we can perform the conversion on both ends and compare
7414 the result for equality. */
7415 tem = double_int_ext (tree_to_double_int (vr->min), precision, unsigned_p);
7416 if (!double_int_equal_p (tree_to_double_int (vr->min), tem))
7418 tem = double_int_ext (tree_to_double_int (vr->max), precision, unsigned_p);
7419 if (!double_int_equal_p (tree_to_double_int (vr->max), tem))
7425 /* Simplify a conversion from integral SSA name to float in STMT. */
7428 simplify_float_conversion_using_ranges (gimple_stmt_iterator *gsi, gimple stmt)
7430 tree rhs1 = gimple_assign_rhs1 (stmt);
7431 value_range_t *vr = get_value_range (rhs1);
7432 enum machine_mode fltmode = TYPE_MODE (TREE_TYPE (gimple_assign_lhs (stmt)));
7433 enum machine_mode mode;
7437 /* We can only handle constant ranges. */
7438 if (vr->type != VR_RANGE
7439 || TREE_CODE (vr->min) != INTEGER_CST
7440 || TREE_CODE (vr->max) != INTEGER_CST)
7443 /* First check if we can use a signed type in place of an unsigned. */
7444 if (TYPE_UNSIGNED (TREE_TYPE (rhs1))
7445 && (can_float_p (fltmode, TYPE_MODE (TREE_TYPE (rhs1)), 0)
7446 != CODE_FOR_nothing)
7447 && range_fits_type_p (vr, GET_MODE_PRECISION
7448 (TYPE_MODE (TREE_TYPE (rhs1))), 0))
7449 mode = TYPE_MODE (TREE_TYPE (rhs1));
7450 /* If we can do the conversion in the current input mode do nothing. */
7451 else if (can_float_p (fltmode, TYPE_MODE (TREE_TYPE (rhs1)),
7452 TYPE_UNSIGNED (TREE_TYPE (rhs1))))
7454 /* Otherwise search for a mode we can use, starting from the narrowest
7455 integer mode available. */
7458 mode = GET_CLASS_NARROWEST_MODE (MODE_INT);
7461 /* If we cannot do a signed conversion to float from mode
7462 or if the value-range does not fit in the signed type
7463 try with a wider mode. */
7464 if (can_float_p (fltmode, mode, 0) != CODE_FOR_nothing
7465 && range_fits_type_p (vr, GET_MODE_PRECISION (mode), 0))
7468 mode = GET_MODE_WIDER_MODE (mode);
7469 /* But do not widen the input. Instead leave that to the
7470 optabs expansion code. */
7471 if (GET_MODE_PRECISION (mode) > TYPE_PRECISION (TREE_TYPE (rhs1)))
7474 while (mode != VOIDmode);
7475 if (mode == VOIDmode)
7479 /* It works, insert a truncation or sign-change before the
7480 float conversion. */
7481 tem = create_tmp_var (build_nonstandard_integer_type
7482 (GET_MODE_PRECISION (mode), 0), NULL);
7483 conv = gimple_build_assign_with_ops (NOP_EXPR, tem, rhs1, NULL_TREE);
7484 tem = make_ssa_name (tem, conv);
7485 gimple_assign_set_lhs (conv, tem);
7486 gsi_insert_before (gsi, conv, GSI_SAME_STMT);
7487 gimple_assign_set_rhs1 (stmt, tem);
7493 /* Simplify STMT using ranges if possible. */
7496 simplify_stmt_using_ranges (gimple_stmt_iterator *gsi)
7498 gimple stmt = gsi_stmt (*gsi);
7499 if (is_gimple_assign (stmt))
7501 enum tree_code rhs_code = gimple_assign_rhs_code (stmt);
7502 tree rhs1 = gimple_assign_rhs1 (stmt);
7508 /* Transform EQ_EXPR, NE_EXPR into BIT_XOR_EXPR or identity
7509 if the RHS is zero or one, and the LHS are known to be boolean
7511 if (INTEGRAL_TYPE_P (TREE_TYPE (rhs1)))
7512 return simplify_truth_ops_using_ranges (gsi, stmt);
7515 /* Transform TRUNC_DIV_EXPR and TRUNC_MOD_EXPR into RSHIFT_EXPR
7516 and BIT_AND_EXPR respectively if the first operand is greater
7517 than zero and the second operand is an exact power of two. */
7518 case TRUNC_DIV_EXPR:
7519 case TRUNC_MOD_EXPR:
7520 if (INTEGRAL_TYPE_P (TREE_TYPE (rhs1))
7521 && integer_pow2p (gimple_assign_rhs2 (stmt)))
7522 return simplify_div_or_mod_using_ranges (stmt);
7525 /* Transform ABS (X) into X or -X as appropriate. */
7527 if (TREE_CODE (rhs1) == SSA_NAME
7528 && INTEGRAL_TYPE_P (TREE_TYPE (rhs1)))
7529 return simplify_abs_using_ranges (stmt);
7534 /* Optimize away BIT_AND_EXPR and BIT_IOR_EXPR
7535 if all the bits being cleared are already cleared or
7536 all the bits being set are already set. */
7537 if (INTEGRAL_TYPE_P (TREE_TYPE (rhs1)))
7538 return simplify_bit_ops_using_ranges (gsi, stmt);
7542 if (TREE_CODE (rhs1) == SSA_NAME
7543 && INTEGRAL_TYPE_P (TREE_TYPE (rhs1)))
7544 return simplify_conversion_using_ranges (stmt);
7548 if (TREE_CODE (rhs1) == SSA_NAME
7549 && INTEGRAL_TYPE_P (TREE_TYPE (rhs1)))
7550 return simplify_float_conversion_using_ranges (gsi, stmt);
7557 else if (gimple_code (stmt) == GIMPLE_COND)
7558 return simplify_cond_using_ranges (stmt);
7559 else if (gimple_code (stmt) == GIMPLE_SWITCH)
7560 return simplify_switch_using_ranges (stmt);
7565 /* If the statement pointed by SI has a predicate whose value can be
7566 computed using the value range information computed by VRP, compute
7567 its value and return true. Otherwise, return false. */
7570 fold_predicate_in (gimple_stmt_iterator *si)
7572 bool assignment_p = false;
7574 gimple stmt = gsi_stmt (*si);
7576 if (is_gimple_assign (stmt)
7577 && TREE_CODE_CLASS (gimple_assign_rhs_code (stmt)) == tcc_comparison)
7579 assignment_p = true;
7580 val = vrp_evaluate_conditional (gimple_assign_rhs_code (stmt),
7581 gimple_assign_rhs1 (stmt),
7582 gimple_assign_rhs2 (stmt),
7585 else if (gimple_code (stmt) == GIMPLE_COND)
7586 val = vrp_evaluate_conditional (gimple_cond_code (stmt),
7587 gimple_cond_lhs (stmt),
7588 gimple_cond_rhs (stmt),
7596 val = fold_convert (gimple_expr_type (stmt), val);
7600 fprintf (dump_file, "Folding predicate ");
7601 print_gimple_expr (dump_file, stmt, 0, 0);
7602 fprintf (dump_file, " to ");
7603 print_generic_expr (dump_file, val, 0);
7604 fprintf (dump_file, "\n");
7607 if (is_gimple_assign (stmt))
7608 gimple_assign_set_rhs_from_tree (si, val);
7611 gcc_assert (gimple_code (stmt) == GIMPLE_COND);
7612 if (integer_zerop (val))
7613 gimple_cond_make_false (stmt);
7614 else if (integer_onep (val))
7615 gimple_cond_make_true (stmt);
7626 /* Callback for substitute_and_fold folding the stmt at *SI. */
7629 vrp_fold_stmt (gimple_stmt_iterator *si)
7631 if (fold_predicate_in (si))
7634 return simplify_stmt_using_ranges (si);
7637 /* Stack of dest,src equivalency pairs that need to be restored after
7638 each attempt to thread a block's incoming edge to an outgoing edge.
7640 A NULL entry is used to mark the end of pairs which need to be
7642 static VEC(tree,heap) *stack;
7644 /* A trivial wrapper so that we can present the generic jump threading
7645 code with a simple API for simplifying statements. STMT is the
7646 statement we want to simplify, WITHIN_STMT provides the location
7647 for any overflow warnings. */
7650 simplify_stmt_for_jump_threading (gimple stmt, gimple within_stmt)
7652 /* We only use VRP information to simplify conditionals. This is
7653 overly conservative, but it's unclear if doing more would be
7654 worth the compile time cost. */
7655 if (gimple_code (stmt) != GIMPLE_COND)
7658 return vrp_evaluate_conditional (gimple_cond_code (stmt),
7659 gimple_cond_lhs (stmt),
7660 gimple_cond_rhs (stmt), within_stmt);
7663 /* Blocks which have more than one predecessor and more than
7664 one successor present jump threading opportunities, i.e.,
7665 when the block is reached from a specific predecessor, we
7666 may be able to determine which of the outgoing edges will
7667 be traversed. When this optimization applies, we are able
7668 to avoid conditionals at runtime and we may expose secondary
7669 optimization opportunities.
7671 This routine is effectively a driver for the generic jump
7672 threading code. It basically just presents the generic code
7673 with edges that may be suitable for jump threading.
7675 Unlike DOM, we do not iterate VRP if jump threading was successful.
7676 While iterating may expose new opportunities for VRP, it is expected
7677 those opportunities would be very limited and the compile time cost
7678 to expose those opportunities would be significant.
7680 As jump threading opportunities are discovered, they are registered
7681 for later realization. */
7684 identify_jump_threads (void)
7691 /* Ugh. When substituting values earlier in this pass we can
7692 wipe the dominance information. So rebuild the dominator
7693 information as we need it within the jump threading code. */
7694 calculate_dominance_info (CDI_DOMINATORS);
7696 /* We do not allow VRP information to be used for jump threading
7697 across a back edge in the CFG. Otherwise it becomes too
7698 difficult to avoid eliminating loop exit tests. Of course
7699 EDGE_DFS_BACK is not accurate at this time so we have to
7701 mark_dfs_back_edges ();
7703 /* Do not thread across edges we are about to remove. Just marking
7704 them as EDGE_DFS_BACK will do. */
7705 FOR_EACH_VEC_ELT (edge, to_remove_edges, i, e)
7706 e->flags |= EDGE_DFS_BACK;
7708 /* Allocate our unwinder stack to unwind any temporary equivalences
7709 that might be recorded. */
7710 stack = VEC_alloc (tree, heap, 20);
7712 /* To avoid lots of silly node creation, we create a single
7713 conditional and just modify it in-place when attempting to
7715 dummy = gimple_build_cond (EQ_EXPR,
7716 integer_zero_node, integer_zero_node,
7719 /* Walk through all the blocks finding those which present a
7720 potential jump threading opportunity. We could set this up
7721 as a dominator walker and record data during the walk, but
7722 I doubt it's worth the effort for the classes of jump
7723 threading opportunities we are trying to identify at this
7724 point in compilation. */
7729 /* If the generic jump threading code does not find this block
7730 interesting, then there is nothing to do. */
7731 if (! potentially_threadable_block (bb))
7734 /* We only care about blocks ending in a COND_EXPR. While there
7735 may be some value in handling SWITCH_EXPR here, I doubt it's
7736 terribly important. */
7737 last = gsi_stmt (gsi_last_bb (bb));
7739 /* We're basically looking for a switch or any kind of conditional with
7740 integral or pointer type arguments. Note the type of the second
7741 argument will be the same as the first argument, so no need to
7742 check it explicitly. */
7743 if (gimple_code (last) == GIMPLE_SWITCH
7744 || (gimple_code (last) == GIMPLE_COND
7745 && TREE_CODE (gimple_cond_lhs (last)) == SSA_NAME
7746 && (INTEGRAL_TYPE_P (TREE_TYPE (gimple_cond_lhs (last)))
7747 || POINTER_TYPE_P (TREE_TYPE (gimple_cond_lhs (last))))
7748 && (TREE_CODE (gimple_cond_rhs (last)) == SSA_NAME
7749 || is_gimple_min_invariant (gimple_cond_rhs (last)))))
7753 /* We've got a block with multiple predecessors and multiple
7754 successors which also ends in a suitable conditional or
7755 switch statement. For each predecessor, see if we can thread
7756 it to a specific successor. */
7757 FOR_EACH_EDGE (e, ei, bb->preds)
7759 /* Do not thread across back edges or abnormal edges
7761 if (e->flags & (EDGE_DFS_BACK | EDGE_COMPLEX))
7764 thread_across_edge (dummy, e, true, &stack,
7765 simplify_stmt_for_jump_threading);
7770 /* We do not actually update the CFG or SSA graphs at this point as
7771 ASSERT_EXPRs are still in the IL and cfg cleanup code does not yet
7772 handle ASSERT_EXPRs gracefully. */
7775 /* We identified all the jump threading opportunities earlier, but could
7776 not transform the CFG at that time. This routine transforms the
7777 CFG and arranges for the dominator tree to be rebuilt if necessary.
7779 Note the SSA graph update will occur during the normal TODO
7780 processing by the pass manager. */
7782 finalize_jump_threads (void)
7784 thread_through_all_blocks (false);
7785 VEC_free (tree, heap, stack);
7789 /* Traverse all the blocks folding conditionals with known ranges. */
7796 values_propagated = true;
7800 fprintf (dump_file, "\nValue ranges after VRP:\n\n");
7801 dump_all_value_ranges (dump_file);
7802 fprintf (dump_file, "\n");
7805 substitute_and_fold (op_with_constant_singleton_value_range,
7806 vrp_fold_stmt, false);
7808 if (warn_array_bounds)
7809 check_all_array_refs ();
7811 /* We must identify jump threading opportunities before we release
7812 the datastructures built by VRP. */
7813 identify_jump_threads ();
7815 /* Free allocated memory. */
7816 for (i = 0; i < num_vr_values; i++)
7819 BITMAP_FREE (vr_value[i]->equiv);
7824 free (vr_phi_edge_counts);
7826 /* So that we can distinguish between VRP data being available
7827 and not available. */
7829 vr_phi_edge_counts = NULL;
7833 /* Main entry point to VRP (Value Range Propagation). This pass is
7834 loosely based on J. R. C. Patterson, ``Accurate Static Branch
7835 Prediction by Value Range Propagation,'' in SIGPLAN Conference on
7836 Programming Language Design and Implementation, pp. 67-78, 1995.
7837 Also available at http://citeseer.ist.psu.edu/patterson95accurate.html
7839 This is essentially an SSA-CCP pass modified to deal with ranges
7840 instead of constants.
7842 While propagating ranges, we may find that two or more SSA name
7843 have equivalent, though distinct ranges. For instance,
7846 2 p_4 = ASSERT_EXPR <p_3, p_3 != 0>
7848 4 p_5 = ASSERT_EXPR <p_4, p_4 == q_2>;
7852 In the code above, pointer p_5 has range [q_2, q_2], but from the
7853 code we can also determine that p_5 cannot be NULL and, if q_2 had
7854 a non-varying range, p_5's range should also be compatible with it.
7856 These equivalences are created by two expressions: ASSERT_EXPR and
7857 copy operations. Since p_5 is an assertion on p_4, and p_4 was the
7858 result of another assertion, then we can use the fact that p_5 and
7859 p_4 are equivalent when evaluating p_5's range.
7861 Together with value ranges, we also propagate these equivalences
7862 between names so that we can take advantage of information from
7863 multiple ranges when doing final replacement. Note that this
7864 equivalency relation is transitive but not symmetric.
7866 In the example above, p_5 is equivalent to p_4, q_2 and p_3, but we
7867 cannot assert that q_2 is equivalent to p_5 because q_2 may be used
7868 in contexts where that assertion does not hold (e.g., in line 6).
7870 TODO, the main difference between this pass and Patterson's is that
7871 we do not propagate edge probabilities. We only compute whether
7872 edges can be taken or not. That is, instead of having a spectrum
7873 of jump probabilities between 0 and 1, we only deal with 0, 1 and
7874 DON'T KNOW. In the future, it may be worthwhile to propagate
7875 probabilities to aid branch prediction. */
7884 loop_optimizer_init (LOOPS_NORMAL | LOOPS_HAVE_RECORDED_EXITS);
7885 rewrite_into_loop_closed_ssa (NULL, TODO_update_ssa);
7888 /* ??? This ends up using stale EDGE_DFS_BACK for liveness computation.
7889 Inserting assertions may split edges which will invalidate
7891 insert_range_assertions ();
7893 /* Estimate number of iterations - but do not use undefined behavior
7894 for this. We can't do this lazily as other functions may compute
7895 this using undefined behavior. */
7896 free_numbers_of_iterations_estimates ();
7897 estimate_numbers_of_iterations (false);
7899 to_remove_edges = VEC_alloc (edge, heap, 10);
7900 to_update_switch_stmts = VEC_alloc (switch_update, heap, 5);
7901 threadedge_initialize_values ();
7903 /* For visiting PHI nodes we need EDGE_DFS_BACK computed. */
7904 mark_dfs_back_edges ();
7907 ssa_propagate (vrp_visit_stmt, vrp_visit_phi_node);
7910 free_numbers_of_iterations_estimates ();
7912 /* ASSERT_EXPRs must be removed before finalizing jump threads
7913 as finalizing jump threads calls the CFG cleanup code which
7914 does not properly handle ASSERT_EXPRs. */
7915 remove_range_assertions ();
7917 /* If we exposed any new variables, go ahead and put them into
7918 SSA form now, before we handle jump threading. This simplifies
7919 interactions between rewriting of _DECL nodes into SSA form
7920 and rewriting SSA_NAME nodes into SSA form after block
7921 duplication and CFG manipulation. */
7922 update_ssa (TODO_update_ssa);
7924 finalize_jump_threads ();
7926 /* Remove dead edges from SWITCH_EXPR optimization. This leaves the
7927 CFG in a broken state and requires a cfg_cleanup run. */
7928 FOR_EACH_VEC_ELT (edge, to_remove_edges, i, e)
7930 /* Update SWITCH_EXPR case label vector. */
7931 FOR_EACH_VEC_ELT (switch_update, to_update_switch_stmts, i, su)
7934 size_t n = TREE_VEC_LENGTH (su->vec);
7936 gimple_switch_set_num_labels (su->stmt, n);
7937 for (j = 0; j < n; j++)
7938 gimple_switch_set_label (su->stmt, j, TREE_VEC_ELT (su->vec, j));
7939 /* As we may have replaced the default label with a regular one
7940 make sure to make it a real default label again. This ensures
7941 optimal expansion. */
7942 label = gimple_switch_default_label (su->stmt);
7943 CASE_LOW (label) = NULL_TREE;
7944 CASE_HIGH (label) = NULL_TREE;
7947 if (VEC_length (edge, to_remove_edges) > 0)
7948 free_dominance_info (CDI_DOMINATORS);
7950 VEC_free (edge, heap, to_remove_edges);
7951 VEC_free (switch_update, heap, to_update_switch_stmts);
7952 threadedge_finalize_values ();
7955 loop_optimizer_finalize ();
7962 return flag_tree_vrp != 0;
7965 struct gimple_opt_pass pass_vrp =
7970 gate_vrp, /* gate */
7971 execute_vrp, /* execute */
7974 0, /* static_pass_number */
7975 TV_TREE_VRP, /* tv_id */
7976 PROP_ssa, /* properties_required */
7977 0, /* properties_provided */
7978 0, /* properties_destroyed */
7979 0, /* todo_flags_start */
7984 | TODO_ggc_collect /* todo_flags_finish */