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)
699 && TREE_CODE (sym) == PARM_DECL)
701 /* Try to use the "nonnull" attribute to create ~[0, 0]
702 anti-ranges for pointers. Note that this is only valid with
703 default definitions of PARM_DECLs. */
704 if (POINTER_TYPE_P (TREE_TYPE (sym))
705 && nonnull_arg_p (sym))
706 set_value_range_to_nonnull (vr, TREE_TYPE (sym));
708 set_value_range_to_varying (vr);
714 /* Return true, if VAL1 and VAL2 are equal values for VRP purposes. */
717 vrp_operand_equal_p (const_tree val1, const_tree val2)
721 if (!val1 || !val2 || !operand_equal_p (val1, val2, 0))
723 if (is_overflow_infinity (val1))
724 return is_overflow_infinity (val2);
728 /* Return true, if the bitmaps B1 and B2 are equal. */
731 vrp_bitmap_equal_p (const_bitmap b1, const_bitmap b2)
734 || ((!b1 || bitmap_empty_p (b1))
735 && (!b2 || bitmap_empty_p (b2)))
737 && bitmap_equal_p (b1, b2)));
740 /* Update the value range and equivalence set for variable VAR to
741 NEW_VR. Return true if NEW_VR is different from VAR's previous
744 NOTE: This function assumes that NEW_VR is a temporary value range
745 object created for the sole purpose of updating VAR's range. The
746 storage used by the equivalence set from NEW_VR will be freed by
747 this function. Do not call update_value_range when NEW_VR
748 is the range object associated with another SSA name. */
751 update_value_range (const_tree var, value_range_t *new_vr)
753 value_range_t *old_vr;
756 /* Update the value range, if necessary. */
757 old_vr = get_value_range (var);
758 is_new = old_vr->type != new_vr->type
759 || !vrp_operand_equal_p (old_vr->min, new_vr->min)
760 || !vrp_operand_equal_p (old_vr->max, new_vr->max)
761 || !vrp_bitmap_equal_p (old_vr->equiv, new_vr->equiv);
764 set_value_range (old_vr, new_vr->type, new_vr->min, new_vr->max,
767 BITMAP_FREE (new_vr->equiv);
773 /* Add VAR and VAR's equivalence set to EQUIV. This is the central
774 point where equivalence processing can be turned on/off. */
777 add_equivalence (bitmap *equiv, const_tree var)
779 unsigned ver = SSA_NAME_VERSION (var);
780 value_range_t *vr = vr_value[ver];
783 *equiv = BITMAP_ALLOC (NULL);
784 bitmap_set_bit (*equiv, ver);
786 bitmap_ior_into (*equiv, vr->equiv);
790 /* Return true if VR is ~[0, 0]. */
793 range_is_nonnull (value_range_t *vr)
795 return vr->type == VR_ANTI_RANGE
796 && integer_zerop (vr->min)
797 && integer_zerop (vr->max);
801 /* Return true if VR is [0, 0]. */
804 range_is_null (value_range_t *vr)
806 return vr->type == VR_RANGE
807 && integer_zerop (vr->min)
808 && integer_zerop (vr->max);
811 /* Return true if max and min of VR are INTEGER_CST. It's not necessary
815 range_int_cst_p (value_range_t *vr)
817 return (vr->type == VR_RANGE
818 && TREE_CODE (vr->max) == INTEGER_CST
819 && TREE_CODE (vr->min) == INTEGER_CST
820 && !TREE_OVERFLOW (vr->max)
821 && !TREE_OVERFLOW (vr->min));
824 /* Return true if VR is a INTEGER_CST singleton. */
827 range_int_cst_singleton_p (value_range_t *vr)
829 return (range_int_cst_p (vr)
830 && tree_int_cst_equal (vr->min, vr->max));
833 /* Return true if value range VR involves at least one symbol. */
836 symbolic_range_p (value_range_t *vr)
838 return (!is_gimple_min_invariant (vr->min)
839 || !is_gimple_min_invariant (vr->max));
842 /* Return true if value range VR uses an overflow infinity. */
845 overflow_infinity_range_p (value_range_t *vr)
847 return (vr->type == VR_RANGE
848 && (is_overflow_infinity (vr->min)
849 || is_overflow_infinity (vr->max)));
852 /* Return false if we can not make a valid comparison based on VR;
853 this will be the case if it uses an overflow infinity and overflow
854 is not undefined (i.e., -fno-strict-overflow is in effect).
855 Otherwise return true, and set *STRICT_OVERFLOW_P to true if VR
856 uses an overflow infinity. */
859 usable_range_p (value_range_t *vr, bool *strict_overflow_p)
861 gcc_assert (vr->type == VR_RANGE);
862 if (is_overflow_infinity (vr->min))
864 *strict_overflow_p = true;
865 if (!TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (vr->min)))
868 if (is_overflow_infinity (vr->max))
870 *strict_overflow_p = true;
871 if (!TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (vr->max)))
878 /* Return true if the result of assignment STMT is know to be non-negative.
879 If the return value is based on the assumption that signed overflow is
880 undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't change
881 *STRICT_OVERFLOW_P.*/
884 gimple_assign_nonnegative_warnv_p (gimple stmt, bool *strict_overflow_p)
886 enum tree_code code = gimple_assign_rhs_code (stmt);
887 switch (get_gimple_rhs_class (code))
889 case GIMPLE_UNARY_RHS:
890 return tree_unary_nonnegative_warnv_p (gimple_assign_rhs_code (stmt),
891 gimple_expr_type (stmt),
892 gimple_assign_rhs1 (stmt),
894 case GIMPLE_BINARY_RHS:
895 return tree_binary_nonnegative_warnv_p (gimple_assign_rhs_code (stmt),
896 gimple_expr_type (stmt),
897 gimple_assign_rhs1 (stmt),
898 gimple_assign_rhs2 (stmt),
900 case GIMPLE_TERNARY_RHS:
902 case GIMPLE_SINGLE_RHS:
903 return tree_single_nonnegative_warnv_p (gimple_assign_rhs1 (stmt),
905 case GIMPLE_INVALID_RHS:
912 /* Return true if return value of call STMT is know to be non-negative.
913 If the return value is based on the assumption that signed overflow is
914 undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't change
915 *STRICT_OVERFLOW_P.*/
918 gimple_call_nonnegative_warnv_p (gimple stmt, bool *strict_overflow_p)
920 tree arg0 = gimple_call_num_args (stmt) > 0 ?
921 gimple_call_arg (stmt, 0) : NULL_TREE;
922 tree arg1 = gimple_call_num_args (stmt) > 1 ?
923 gimple_call_arg (stmt, 1) : NULL_TREE;
925 return tree_call_nonnegative_warnv_p (gimple_expr_type (stmt),
926 gimple_call_fndecl (stmt),
932 /* Return true if STMT is know to to compute a non-negative value.
933 If the return value is based on the assumption that signed overflow is
934 undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't change
935 *STRICT_OVERFLOW_P.*/
938 gimple_stmt_nonnegative_warnv_p (gimple stmt, bool *strict_overflow_p)
940 switch (gimple_code (stmt))
943 return gimple_assign_nonnegative_warnv_p (stmt, strict_overflow_p);
945 return gimple_call_nonnegative_warnv_p (stmt, strict_overflow_p);
951 /* Return true if the result of assignment STMT is know to be non-zero.
952 If the return value is based on the assumption that signed overflow is
953 undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't change
954 *STRICT_OVERFLOW_P.*/
957 gimple_assign_nonzero_warnv_p (gimple stmt, bool *strict_overflow_p)
959 enum tree_code code = gimple_assign_rhs_code (stmt);
960 switch (get_gimple_rhs_class (code))
962 case GIMPLE_UNARY_RHS:
963 return tree_unary_nonzero_warnv_p (gimple_assign_rhs_code (stmt),
964 gimple_expr_type (stmt),
965 gimple_assign_rhs1 (stmt),
967 case GIMPLE_BINARY_RHS:
968 return tree_binary_nonzero_warnv_p (gimple_assign_rhs_code (stmt),
969 gimple_expr_type (stmt),
970 gimple_assign_rhs1 (stmt),
971 gimple_assign_rhs2 (stmt),
973 case GIMPLE_TERNARY_RHS:
975 case GIMPLE_SINGLE_RHS:
976 return tree_single_nonzero_warnv_p (gimple_assign_rhs1 (stmt),
978 case GIMPLE_INVALID_RHS:
985 /* Return true if STMT is know to to compute a non-zero value.
986 If the return value is based on the assumption that signed overflow is
987 undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't change
988 *STRICT_OVERFLOW_P.*/
991 gimple_stmt_nonzero_warnv_p (gimple stmt, bool *strict_overflow_p)
993 switch (gimple_code (stmt))
996 return gimple_assign_nonzero_warnv_p (stmt, strict_overflow_p);
998 return gimple_alloca_call_p (stmt);
1004 /* Like tree_expr_nonzero_warnv_p, but this function uses value ranges
1008 vrp_stmt_computes_nonzero (gimple stmt, bool *strict_overflow_p)
1010 if (gimple_stmt_nonzero_warnv_p (stmt, strict_overflow_p))
1013 /* If we have an expression of the form &X->a, then the expression
1014 is nonnull if X is nonnull. */
1015 if (is_gimple_assign (stmt)
1016 && gimple_assign_rhs_code (stmt) == ADDR_EXPR)
1018 tree expr = gimple_assign_rhs1 (stmt);
1019 tree base = get_base_address (TREE_OPERAND (expr, 0));
1021 if (base != NULL_TREE
1022 && TREE_CODE (base) == MEM_REF
1023 && TREE_CODE (TREE_OPERAND (base, 0)) == SSA_NAME)
1025 value_range_t *vr = get_value_range (TREE_OPERAND (base, 0));
1026 if (range_is_nonnull (vr))
1034 /* Returns true if EXPR is a valid value (as expected by compare_values) --
1035 a gimple invariant, or SSA_NAME +- CST. */
1038 valid_value_p (tree expr)
1040 if (TREE_CODE (expr) == SSA_NAME)
1043 if (TREE_CODE (expr) == PLUS_EXPR
1044 || TREE_CODE (expr) == MINUS_EXPR)
1045 return (TREE_CODE (TREE_OPERAND (expr, 0)) == SSA_NAME
1046 && TREE_CODE (TREE_OPERAND (expr, 1)) == INTEGER_CST);
1048 return is_gimple_min_invariant (expr);
1054 -2 if those are incomparable. */
1056 operand_less_p (tree val, tree val2)
1058 /* LT is folded faster than GE and others. Inline the common case. */
1059 if (TREE_CODE (val) == INTEGER_CST && TREE_CODE (val2) == INTEGER_CST)
1061 if (TYPE_UNSIGNED (TREE_TYPE (val)))
1062 return INT_CST_LT_UNSIGNED (val, val2);
1065 if (INT_CST_LT (val, val2))
1073 fold_defer_overflow_warnings ();
1075 tcmp = fold_binary_to_constant (LT_EXPR, boolean_type_node, val, val2);
1077 fold_undefer_and_ignore_overflow_warnings ();
1080 || TREE_CODE (tcmp) != INTEGER_CST)
1083 if (!integer_zerop (tcmp))
1087 /* val >= val2, not considering overflow infinity. */
1088 if (is_negative_overflow_infinity (val))
1089 return is_negative_overflow_infinity (val2) ? 0 : 1;
1090 else if (is_positive_overflow_infinity (val2))
1091 return is_positive_overflow_infinity (val) ? 0 : 1;
1096 /* Compare two values VAL1 and VAL2. Return
1098 -2 if VAL1 and VAL2 cannot be compared at compile-time,
1101 +1 if VAL1 > VAL2, and
1104 This is similar to tree_int_cst_compare but supports pointer values
1105 and values that cannot be compared at compile time.
1107 If STRICT_OVERFLOW_P is not NULL, then set *STRICT_OVERFLOW_P to
1108 true if the return value is only valid if we assume that signed
1109 overflow is undefined. */
1112 compare_values_warnv (tree val1, tree val2, bool *strict_overflow_p)
1117 /* Below we rely on the fact that VAL1 and VAL2 are both pointers or
1119 gcc_assert (POINTER_TYPE_P (TREE_TYPE (val1))
1120 == POINTER_TYPE_P (TREE_TYPE (val2)));
1121 /* Convert the two values into the same type. This is needed because
1122 sizetype causes sign extension even for unsigned types. */
1123 val2 = fold_convert (TREE_TYPE (val1), val2);
1124 STRIP_USELESS_TYPE_CONVERSION (val2);
1126 if ((TREE_CODE (val1) == SSA_NAME
1127 || TREE_CODE (val1) == PLUS_EXPR
1128 || TREE_CODE (val1) == MINUS_EXPR)
1129 && (TREE_CODE (val2) == SSA_NAME
1130 || TREE_CODE (val2) == PLUS_EXPR
1131 || TREE_CODE (val2) == MINUS_EXPR))
1133 tree n1, c1, n2, c2;
1134 enum tree_code code1, code2;
1136 /* If VAL1 and VAL2 are of the form 'NAME [+-] CST' or 'NAME',
1137 return -1 or +1 accordingly. If VAL1 and VAL2 don't use the
1138 same name, return -2. */
1139 if (TREE_CODE (val1) == SSA_NAME)
1147 code1 = TREE_CODE (val1);
1148 n1 = TREE_OPERAND (val1, 0);
1149 c1 = TREE_OPERAND (val1, 1);
1150 if (tree_int_cst_sgn (c1) == -1)
1152 if (is_negative_overflow_infinity (c1))
1154 c1 = fold_unary_to_constant (NEGATE_EXPR, TREE_TYPE (c1), c1);
1157 code1 = code1 == MINUS_EXPR ? PLUS_EXPR : MINUS_EXPR;
1161 if (TREE_CODE (val2) == SSA_NAME)
1169 code2 = TREE_CODE (val2);
1170 n2 = TREE_OPERAND (val2, 0);
1171 c2 = TREE_OPERAND (val2, 1);
1172 if (tree_int_cst_sgn (c2) == -1)
1174 if (is_negative_overflow_infinity (c2))
1176 c2 = fold_unary_to_constant (NEGATE_EXPR, TREE_TYPE (c2), c2);
1179 code2 = code2 == MINUS_EXPR ? PLUS_EXPR : MINUS_EXPR;
1183 /* Both values must use the same name. */
1187 if (code1 == SSA_NAME
1188 && code2 == SSA_NAME)
1192 /* If overflow is defined we cannot simplify more. */
1193 if (!TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (val1)))
1196 if (strict_overflow_p != NULL
1197 && (code1 == SSA_NAME || !TREE_NO_WARNING (val1))
1198 && (code2 == SSA_NAME || !TREE_NO_WARNING (val2)))
1199 *strict_overflow_p = true;
1201 if (code1 == SSA_NAME)
1203 if (code2 == PLUS_EXPR)
1204 /* NAME < NAME + CST */
1206 else if (code2 == MINUS_EXPR)
1207 /* NAME > NAME - CST */
1210 else if (code1 == PLUS_EXPR)
1212 if (code2 == SSA_NAME)
1213 /* NAME + CST > NAME */
1215 else if (code2 == PLUS_EXPR)
1216 /* NAME + CST1 > NAME + CST2, if CST1 > CST2 */
1217 return compare_values_warnv (c1, c2, strict_overflow_p);
1218 else if (code2 == MINUS_EXPR)
1219 /* NAME + CST1 > NAME - CST2 */
1222 else if (code1 == MINUS_EXPR)
1224 if (code2 == SSA_NAME)
1225 /* NAME - CST < NAME */
1227 else if (code2 == PLUS_EXPR)
1228 /* NAME - CST1 < NAME + CST2 */
1230 else if (code2 == MINUS_EXPR)
1231 /* NAME - CST1 > NAME - CST2, if CST1 < CST2. Notice that
1232 C1 and C2 are swapped in the call to compare_values. */
1233 return compare_values_warnv (c2, c1, strict_overflow_p);
1239 /* We cannot compare non-constants. */
1240 if (!is_gimple_min_invariant (val1) || !is_gimple_min_invariant (val2))
1243 if (!POINTER_TYPE_P (TREE_TYPE (val1)))
1245 /* We cannot compare overflowed values, except for overflow
1247 if (TREE_OVERFLOW (val1) || TREE_OVERFLOW (val2))
1249 if (strict_overflow_p != NULL)
1250 *strict_overflow_p = true;
1251 if (is_negative_overflow_infinity (val1))
1252 return is_negative_overflow_infinity (val2) ? 0 : -1;
1253 else if (is_negative_overflow_infinity (val2))
1255 else if (is_positive_overflow_infinity (val1))
1256 return is_positive_overflow_infinity (val2) ? 0 : 1;
1257 else if (is_positive_overflow_infinity (val2))
1262 return tree_int_cst_compare (val1, val2);
1268 /* First see if VAL1 and VAL2 are not the same. */
1269 if (val1 == val2 || operand_equal_p (val1, val2, 0))
1272 /* If VAL1 is a lower address than VAL2, return -1. */
1273 if (operand_less_p (val1, val2) == 1)
1276 /* If VAL1 is a higher address than VAL2, return +1. */
1277 if (operand_less_p (val2, val1) == 1)
1280 /* If VAL1 is different than VAL2, return +2.
1281 For integer constants we either have already returned -1 or 1
1282 or they are equivalent. We still might succeed in proving
1283 something about non-trivial operands. */
1284 if (TREE_CODE (val1) != INTEGER_CST
1285 || TREE_CODE (val2) != INTEGER_CST)
1287 t = fold_binary_to_constant (NE_EXPR, boolean_type_node, val1, val2);
1288 if (t && integer_onep (t))
1296 /* Compare values like compare_values_warnv, but treat comparisons of
1297 nonconstants which rely on undefined overflow as incomparable. */
1300 compare_values (tree val1, tree val2)
1306 ret = compare_values_warnv (val1, val2, &sop);
1308 && (!is_gimple_min_invariant (val1) || !is_gimple_min_invariant (val2)))
1314 /* Return 1 if VAL is inside value range VR (VR->MIN <= VAL <= VR->MAX),
1315 0 if VAL is not inside VR,
1316 -2 if we cannot tell either way.
1318 FIXME, the current semantics of this functions are a bit quirky
1319 when taken in the context of VRP. In here we do not care
1320 about VR's type. If VR is the anti-range ~[3, 5] the call
1321 value_inside_range (4, VR) will return 1.
1323 This is counter-intuitive in a strict sense, but the callers
1324 currently expect this. They are calling the function
1325 merely to determine whether VR->MIN <= VAL <= VR->MAX. The
1326 callers are applying the VR_RANGE/VR_ANTI_RANGE semantics
1329 This also applies to value_ranges_intersect_p and
1330 range_includes_zero_p. The semantics of VR_RANGE and
1331 VR_ANTI_RANGE should be encoded here, but that also means
1332 adapting the users of these functions to the new semantics.
1334 Benchmark compile/20001226-1.c compilation time after changing this
1338 value_inside_range (tree val, value_range_t * vr)
1342 cmp1 = operand_less_p (val, vr->min);
1348 cmp2 = operand_less_p (vr->max, val);
1356 /* Return true if value ranges VR0 and VR1 have a non-empty
1359 Benchmark compile/20001226-1.c compilation time after changing this
1364 value_ranges_intersect_p (value_range_t *vr0, value_range_t *vr1)
1366 /* The value ranges do not intersect if the maximum of the first range is
1367 less than the minimum of the second range or vice versa.
1368 When those relations are unknown, we can't do any better. */
1369 if (operand_less_p (vr0->max, vr1->min) != 0)
1371 if (operand_less_p (vr1->max, vr0->min) != 0)
1377 /* Return true if VR includes the value zero, false otherwise. FIXME,
1378 currently this will return false for an anti-range like ~[-4, 3].
1379 This will be wrong when the semantics of value_inside_range are
1380 modified (currently the users of this function expect these
1384 range_includes_zero_p (value_range_t *vr)
1388 gcc_assert (vr->type != VR_UNDEFINED
1389 && vr->type != VR_VARYING
1390 && !symbolic_range_p (vr));
1392 zero = build_int_cst (TREE_TYPE (vr->min), 0);
1393 return (value_inside_range (zero, vr) == 1);
1396 /* Return true if *VR is know to only contain nonnegative values. */
1399 value_range_nonnegative_p (value_range_t *vr)
1401 if (vr->type == VR_RANGE)
1403 int result = compare_values (vr->min, integer_zero_node);
1404 return (result == 0 || result == 1);
1406 else if (vr->type == VR_ANTI_RANGE)
1408 int result = compare_values (vr->max, integer_zero_node);
1409 return result == -1;
1415 /* Return true if T, an SSA_NAME, is known to be nonnegative. Return
1416 false otherwise or if no value range information is available. */
1419 ssa_name_nonnegative_p (const_tree t)
1421 value_range_t *vr = get_value_range (t);
1423 if (INTEGRAL_TYPE_P (t)
1424 && TYPE_UNSIGNED (t))
1430 return value_range_nonnegative_p (vr);
1433 /* If *VR has a value rante that is a single constant value return that,
1434 otherwise return NULL_TREE. */
1437 value_range_constant_singleton (value_range_t *vr)
1439 if (vr->type == VR_RANGE
1440 && operand_equal_p (vr->min, vr->max, 0)
1441 && is_gimple_min_invariant (vr->min))
1447 /* If OP has a value range with a single constant value return that,
1448 otherwise return NULL_TREE. This returns OP itself if OP is a
1452 op_with_constant_singleton_value_range (tree op)
1454 if (is_gimple_min_invariant (op))
1457 if (TREE_CODE (op) != SSA_NAME)
1460 return value_range_constant_singleton (get_value_range (op));
1463 /* Return true if op is in a boolean [0, 1] value-range. */
1466 op_with_boolean_value_range_p (tree op)
1470 if (TYPE_PRECISION (TREE_TYPE (op)) == 1)
1473 if (integer_zerop (op)
1474 || integer_onep (op))
1477 if (TREE_CODE (op) != SSA_NAME)
1480 vr = get_value_range (op);
1481 return (vr->type == VR_RANGE
1482 && integer_zerop (vr->min)
1483 && integer_onep (vr->max));
1486 /* Extract value range information from an ASSERT_EXPR EXPR and store
1490 extract_range_from_assert (value_range_t *vr_p, tree expr)
1492 tree var, cond, limit, min, max, type;
1493 value_range_t *var_vr, *limit_vr;
1494 enum tree_code cond_code;
1496 var = ASSERT_EXPR_VAR (expr);
1497 cond = ASSERT_EXPR_COND (expr);
1499 gcc_assert (COMPARISON_CLASS_P (cond));
1501 /* Find VAR in the ASSERT_EXPR conditional. */
1502 if (var == TREE_OPERAND (cond, 0)
1503 || TREE_CODE (TREE_OPERAND (cond, 0)) == PLUS_EXPR
1504 || TREE_CODE (TREE_OPERAND (cond, 0)) == NOP_EXPR)
1506 /* If the predicate is of the form VAR COMP LIMIT, then we just
1507 take LIMIT from the RHS and use the same comparison code. */
1508 cond_code = TREE_CODE (cond);
1509 limit = TREE_OPERAND (cond, 1);
1510 cond = TREE_OPERAND (cond, 0);
1514 /* If the predicate is of the form LIMIT COMP VAR, then we need
1515 to flip around the comparison code to create the proper range
1517 cond_code = swap_tree_comparison (TREE_CODE (cond));
1518 limit = TREE_OPERAND (cond, 0);
1519 cond = TREE_OPERAND (cond, 1);
1522 limit = avoid_overflow_infinity (limit);
1524 type = TREE_TYPE (limit);
1525 gcc_assert (limit != var);
1527 /* For pointer arithmetic, we only keep track of pointer equality
1529 if (POINTER_TYPE_P (type) && cond_code != NE_EXPR && cond_code != EQ_EXPR)
1531 set_value_range_to_varying (vr_p);
1535 /* If LIMIT is another SSA name and LIMIT has a range of its own,
1536 try to use LIMIT's range to avoid creating symbolic ranges
1538 limit_vr = (TREE_CODE (limit) == SSA_NAME) ? get_value_range (limit) : NULL;
1540 /* LIMIT's range is only interesting if it has any useful information. */
1542 && (limit_vr->type == VR_UNDEFINED
1543 || limit_vr->type == VR_VARYING
1544 || symbolic_range_p (limit_vr)))
1547 /* Initially, the new range has the same set of equivalences of
1548 VAR's range. This will be revised before returning the final
1549 value. Since assertions may be chained via mutually exclusive
1550 predicates, we will need to trim the set of equivalences before
1552 gcc_assert (vr_p->equiv == NULL);
1553 add_equivalence (&vr_p->equiv, var);
1555 /* Extract a new range based on the asserted comparison for VAR and
1556 LIMIT's value range. Notice that if LIMIT has an anti-range, we
1557 will only use it for equality comparisons (EQ_EXPR). For any
1558 other kind of assertion, we cannot derive a range from LIMIT's
1559 anti-range that can be used to describe the new range. For
1560 instance, ASSERT_EXPR <x_2, x_2 <= b_4>. If b_4 is ~[2, 10],
1561 then b_4 takes on the ranges [-INF, 1] and [11, +INF]. There is
1562 no single range for x_2 that could describe LE_EXPR, so we might
1563 as well build the range [b_4, +INF] for it.
1564 One special case we handle is extracting a range from a
1565 range test encoded as (unsigned)var + CST <= limit. */
1566 if (TREE_CODE (cond) == NOP_EXPR
1567 || TREE_CODE (cond) == PLUS_EXPR)
1569 if (TREE_CODE (cond) == PLUS_EXPR)
1571 min = fold_build1 (NEGATE_EXPR, TREE_TYPE (TREE_OPERAND (cond, 1)),
1572 TREE_OPERAND (cond, 1));
1573 max = int_const_binop (PLUS_EXPR, limit, min);
1574 cond = TREE_OPERAND (cond, 0);
1578 min = build_int_cst (TREE_TYPE (var), 0);
1582 /* Make sure to not set TREE_OVERFLOW on the final type
1583 conversion. We are willingly interpreting large positive
1584 unsigned values as negative singed values here. */
1585 min = force_fit_type_double (TREE_TYPE (var), tree_to_double_int (min),
1587 max = force_fit_type_double (TREE_TYPE (var), tree_to_double_int (max),
1590 /* We can transform a max, min range to an anti-range or
1591 vice-versa. Use set_and_canonicalize_value_range which does
1593 if (cond_code == LE_EXPR)
1594 set_and_canonicalize_value_range (vr_p, VR_RANGE,
1595 min, max, vr_p->equiv);
1596 else if (cond_code == GT_EXPR)
1597 set_and_canonicalize_value_range (vr_p, VR_ANTI_RANGE,
1598 min, max, vr_p->equiv);
1602 else if (cond_code == EQ_EXPR)
1604 enum value_range_type range_type;
1608 range_type = limit_vr->type;
1609 min = limit_vr->min;
1610 max = limit_vr->max;
1614 range_type = VR_RANGE;
1619 set_value_range (vr_p, range_type, min, max, vr_p->equiv);
1621 /* When asserting the equality VAR == LIMIT and LIMIT is another
1622 SSA name, the new range will also inherit the equivalence set
1624 if (TREE_CODE (limit) == SSA_NAME)
1625 add_equivalence (&vr_p->equiv, limit);
1627 else if (cond_code == NE_EXPR)
1629 /* As described above, when LIMIT's range is an anti-range and
1630 this assertion is an inequality (NE_EXPR), then we cannot
1631 derive anything from the anti-range. For instance, if
1632 LIMIT's range was ~[0, 0], the assertion 'VAR != LIMIT' does
1633 not imply that VAR's range is [0, 0]. So, in the case of
1634 anti-ranges, we just assert the inequality using LIMIT and
1637 If LIMIT_VR is a range, we can only use it to build a new
1638 anti-range if LIMIT_VR is a single-valued range. For
1639 instance, if LIMIT_VR is [0, 1], the predicate
1640 VAR != [0, 1] does not mean that VAR's range is ~[0, 1].
1641 Rather, it means that for value 0 VAR should be ~[0, 0]
1642 and for value 1, VAR should be ~[1, 1]. We cannot
1643 represent these ranges.
1645 The only situation in which we can build a valid
1646 anti-range is when LIMIT_VR is a single-valued range
1647 (i.e., LIMIT_VR->MIN == LIMIT_VR->MAX). In that case,
1648 build the anti-range ~[LIMIT_VR->MIN, LIMIT_VR->MAX]. */
1650 && limit_vr->type == VR_RANGE
1651 && compare_values (limit_vr->min, limit_vr->max) == 0)
1653 min = limit_vr->min;
1654 max = limit_vr->max;
1658 /* In any other case, we cannot use LIMIT's range to build a
1659 valid anti-range. */
1663 /* If MIN and MAX cover the whole range for their type, then
1664 just use the original LIMIT. */
1665 if (INTEGRAL_TYPE_P (type)
1666 && vrp_val_is_min (min)
1667 && vrp_val_is_max (max))
1670 set_value_range (vr_p, VR_ANTI_RANGE, min, max, vr_p->equiv);
1672 else if (cond_code == LE_EXPR || cond_code == LT_EXPR)
1674 min = TYPE_MIN_VALUE (type);
1676 if (limit_vr == NULL || limit_vr->type == VR_ANTI_RANGE)
1680 /* If LIMIT_VR is of the form [N1, N2], we need to build the
1681 range [MIN, N2] for LE_EXPR and [MIN, N2 - 1] for
1683 max = limit_vr->max;
1686 /* If the maximum value forces us to be out of bounds, simply punt.
1687 It would be pointless to try and do anything more since this
1688 all should be optimized away above us. */
1689 if ((cond_code == LT_EXPR
1690 && compare_values (max, min) == 0)
1691 || (CONSTANT_CLASS_P (max) && TREE_OVERFLOW (max)))
1692 set_value_range_to_varying (vr_p);
1695 /* For LT_EXPR, we create the range [MIN, MAX - 1]. */
1696 if (cond_code == LT_EXPR)
1698 tree one = build_int_cst (type, 1);
1699 max = fold_build2 (MINUS_EXPR, type, max, one);
1701 TREE_NO_WARNING (max) = 1;
1704 set_value_range (vr_p, VR_RANGE, min, max, vr_p->equiv);
1707 else if (cond_code == GE_EXPR || cond_code == GT_EXPR)
1709 max = TYPE_MAX_VALUE (type);
1711 if (limit_vr == NULL || limit_vr->type == VR_ANTI_RANGE)
1715 /* If LIMIT_VR is of the form [N1, N2], we need to build the
1716 range [N1, MAX] for GE_EXPR and [N1 + 1, MAX] for
1718 min = limit_vr->min;
1721 /* If the minimum value forces us to be out of bounds, simply punt.
1722 It would be pointless to try and do anything more since this
1723 all should be optimized away above us. */
1724 if ((cond_code == GT_EXPR
1725 && compare_values (min, max) == 0)
1726 || (CONSTANT_CLASS_P (min) && TREE_OVERFLOW (min)))
1727 set_value_range_to_varying (vr_p);
1730 /* For GT_EXPR, we create the range [MIN + 1, MAX]. */
1731 if (cond_code == GT_EXPR)
1733 tree one = build_int_cst (type, 1);
1734 min = fold_build2 (PLUS_EXPR, type, min, one);
1736 TREE_NO_WARNING (min) = 1;
1739 set_value_range (vr_p, VR_RANGE, min, max, vr_p->equiv);
1745 /* If VAR already had a known range, it may happen that the new
1746 range we have computed and VAR's range are not compatible. For
1750 p_6 = ASSERT_EXPR <p_5, p_5 == NULL>;
1752 p_8 = ASSERT_EXPR <p_6, p_6 != NULL>;
1754 While the above comes from a faulty program, it will cause an ICE
1755 later because p_8 and p_6 will have incompatible ranges and at
1756 the same time will be considered equivalent. A similar situation
1760 i_6 = ASSERT_EXPR <i_5, i_5 > 10>;
1762 i_7 = ASSERT_EXPR <i_6, i_6 < 5>;
1764 Again i_6 and i_7 will have incompatible ranges. It would be
1765 pointless to try and do anything with i_7's range because
1766 anything dominated by 'if (i_5 < 5)' will be optimized away.
1767 Note, due to the wa in which simulation proceeds, the statement
1768 i_7 = ASSERT_EXPR <...> we would never be visited because the
1769 conditional 'if (i_5 < 5)' always evaluates to false. However,
1770 this extra check does not hurt and may protect against future
1771 changes to VRP that may get into a situation similar to the
1772 NULL pointer dereference example.
1774 Note that these compatibility tests are only needed when dealing
1775 with ranges or a mix of range and anti-range. If VAR_VR and VR_P
1776 are both anti-ranges, they will always be compatible, because two
1777 anti-ranges will always have a non-empty intersection. */
1779 var_vr = get_value_range (var);
1781 /* We may need to make adjustments when VR_P and VAR_VR are numeric
1782 ranges or anti-ranges. */
1783 if (vr_p->type == VR_VARYING
1784 || vr_p->type == VR_UNDEFINED
1785 || var_vr->type == VR_VARYING
1786 || var_vr->type == VR_UNDEFINED
1787 || symbolic_range_p (vr_p)
1788 || symbolic_range_p (var_vr))
1791 if (var_vr->type == VR_RANGE && vr_p->type == VR_RANGE)
1793 /* If the two ranges have a non-empty intersection, we can
1794 refine the resulting range. Since the assert expression
1795 creates an equivalency and at the same time it asserts a
1796 predicate, we can take the intersection of the two ranges to
1797 get better precision. */
1798 if (value_ranges_intersect_p (var_vr, vr_p))
1800 /* Use the larger of the two minimums. */
1801 if (compare_values (vr_p->min, var_vr->min) == -1)
1806 /* Use the smaller of the two maximums. */
1807 if (compare_values (vr_p->max, var_vr->max) == 1)
1812 set_value_range (vr_p, vr_p->type, min, max, vr_p->equiv);
1816 /* The two ranges do not intersect, set the new range to
1817 VARYING, because we will not be able to do anything
1818 meaningful with it. */
1819 set_value_range_to_varying (vr_p);
1822 else if ((var_vr->type == VR_RANGE && vr_p->type == VR_ANTI_RANGE)
1823 || (var_vr->type == VR_ANTI_RANGE && vr_p->type == VR_RANGE))
1825 /* A range and an anti-range will cancel each other only if
1826 their ends are the same. For instance, in the example above,
1827 p_8's range ~[0, 0] and p_6's range [0, 0] are incompatible,
1828 so VR_P should be set to VR_VARYING. */
1829 if (compare_values (var_vr->min, vr_p->min) == 0
1830 && compare_values (var_vr->max, vr_p->max) == 0)
1831 set_value_range_to_varying (vr_p);
1834 tree min, max, anti_min, anti_max, real_min, real_max;
1837 /* We want to compute the logical AND of the two ranges;
1838 there are three cases to consider.
1841 1. The VR_ANTI_RANGE range is completely within the
1842 VR_RANGE and the endpoints of the ranges are
1843 different. In that case the resulting range
1844 should be whichever range is more precise.
1845 Typically that will be the VR_RANGE.
1847 2. The VR_ANTI_RANGE is completely disjoint from
1848 the VR_RANGE. In this case the resulting range
1849 should be the VR_RANGE.
1851 3. There is some overlap between the VR_ANTI_RANGE
1854 3a. If the high limit of the VR_ANTI_RANGE resides
1855 within the VR_RANGE, then the result is a new
1856 VR_RANGE starting at the high limit of the
1857 VR_ANTI_RANGE + 1 and extending to the
1858 high limit of the original VR_RANGE.
1860 3b. If the low limit of the VR_ANTI_RANGE resides
1861 within the VR_RANGE, then the result is a new
1862 VR_RANGE starting at the low limit of the original
1863 VR_RANGE and extending to the low limit of the
1864 VR_ANTI_RANGE - 1. */
1865 if (vr_p->type == VR_ANTI_RANGE)
1867 anti_min = vr_p->min;
1868 anti_max = vr_p->max;
1869 real_min = var_vr->min;
1870 real_max = var_vr->max;
1874 anti_min = var_vr->min;
1875 anti_max = var_vr->max;
1876 real_min = vr_p->min;
1877 real_max = vr_p->max;
1881 /* Case 1, VR_ANTI_RANGE completely within VR_RANGE,
1882 not including any endpoints. */
1883 if (compare_values (anti_max, real_max) == -1
1884 && compare_values (anti_min, real_min) == 1)
1886 /* If the range is covering the whole valid range of
1887 the type keep the anti-range. */
1888 if (!vrp_val_is_min (real_min)
1889 || !vrp_val_is_max (real_max))
1890 set_value_range (vr_p, VR_RANGE, real_min,
1891 real_max, vr_p->equiv);
1893 /* Case 2, VR_ANTI_RANGE completely disjoint from
1895 else if (compare_values (anti_min, real_max) == 1
1896 || compare_values (anti_max, real_min) == -1)
1898 set_value_range (vr_p, VR_RANGE, real_min,
1899 real_max, vr_p->equiv);
1901 /* Case 3a, the anti-range extends into the low
1902 part of the real range. Thus creating a new
1903 low for the real range. */
1904 else if (((cmp = compare_values (anti_max, real_min)) == 1
1906 && compare_values (anti_max, real_max) == -1)
1908 gcc_assert (!is_positive_overflow_infinity (anti_max));
1909 if (needs_overflow_infinity (TREE_TYPE (anti_max))
1910 && vrp_val_is_max (anti_max))
1912 if (!supports_overflow_infinity (TREE_TYPE (var_vr->min)))
1914 set_value_range_to_varying (vr_p);
1917 min = positive_overflow_infinity (TREE_TYPE (var_vr->min));
1919 else if (!POINTER_TYPE_P (TREE_TYPE (var_vr->min)))
1920 min = fold_build2 (PLUS_EXPR, TREE_TYPE (var_vr->min),
1922 build_int_cst (TREE_TYPE (var_vr->min), 1));
1924 min = fold_build_pointer_plus_hwi (anti_max, 1);
1926 set_value_range (vr_p, VR_RANGE, min, max, vr_p->equiv);
1928 /* Case 3b, the anti-range extends into the high
1929 part of the real range. Thus creating a new
1930 higher for the real range. */
1931 else if (compare_values (anti_min, real_min) == 1
1932 && ((cmp = compare_values (anti_min, real_max)) == -1
1935 gcc_assert (!is_negative_overflow_infinity (anti_min));
1936 if (needs_overflow_infinity (TREE_TYPE (anti_min))
1937 && vrp_val_is_min (anti_min))
1939 if (!supports_overflow_infinity (TREE_TYPE (var_vr->min)))
1941 set_value_range_to_varying (vr_p);
1944 max = negative_overflow_infinity (TREE_TYPE (var_vr->min));
1946 else if (!POINTER_TYPE_P (TREE_TYPE (var_vr->min)))
1947 max = fold_build2 (MINUS_EXPR, TREE_TYPE (var_vr->min),
1949 build_int_cst (TREE_TYPE (var_vr->min), 1));
1951 max = fold_build_pointer_plus_hwi (anti_min, -1);
1953 set_value_range (vr_p, VR_RANGE, min, max, vr_p->equiv);
1960 /* Extract range information from SSA name VAR and store it in VR. If
1961 VAR has an interesting range, use it. Otherwise, create the
1962 range [VAR, VAR] and return it. This is useful in situations where
1963 we may have conditionals testing values of VARYING names. For
1970 Even if y_5 is deemed VARYING, we can determine that x_3 > y_5 is
1974 extract_range_from_ssa_name (value_range_t *vr, tree var)
1976 value_range_t *var_vr = get_value_range (var);
1978 if (var_vr->type != VR_UNDEFINED && var_vr->type != VR_VARYING)
1979 copy_value_range (vr, var_vr);
1981 set_value_range (vr, VR_RANGE, var, var, NULL);
1983 add_equivalence (&vr->equiv, var);
1987 /* Wrapper around int_const_binop. If the operation overflows and we
1988 are not using wrapping arithmetic, then adjust the result to be
1989 -INF or +INF depending on CODE, VAL1 and VAL2. This can return
1990 NULL_TREE if we need to use an overflow infinity representation but
1991 the type does not support it. */
1994 vrp_int_const_binop (enum tree_code code, tree val1, tree val2)
1998 res = int_const_binop (code, val1, val2);
2000 /* If we are using unsigned arithmetic, operate symbolically
2001 on -INF and +INF as int_const_binop only handles signed overflow. */
2002 if (TYPE_UNSIGNED (TREE_TYPE (val1)))
2004 int checkz = compare_values (res, val1);
2005 bool overflow = false;
2007 /* Ensure that res = val1 [+*] val2 >= val1
2008 or that res = val1 - val2 <= val1. */
2009 if ((code == PLUS_EXPR
2010 && !(checkz == 1 || checkz == 0))
2011 || (code == MINUS_EXPR
2012 && !(checkz == 0 || checkz == -1)))
2016 /* Checking for multiplication overflow is done by dividing the
2017 output of the multiplication by the first input of the
2018 multiplication. If the result of that division operation is
2019 not equal to the second input of the multiplication, then the
2020 multiplication overflowed. */
2021 else if (code == MULT_EXPR && !integer_zerop (val1))
2023 tree tmp = int_const_binop (TRUNC_DIV_EXPR,
2026 int check = compare_values (tmp, val2);
2034 res = copy_node (res);
2035 TREE_OVERFLOW (res) = 1;
2039 else if (TYPE_OVERFLOW_WRAPS (TREE_TYPE (val1)))
2040 /* If the singed operation wraps then int_const_binop has done
2041 everything we want. */
2043 else if ((TREE_OVERFLOW (res)
2044 && !TREE_OVERFLOW (val1)
2045 && !TREE_OVERFLOW (val2))
2046 || is_overflow_infinity (val1)
2047 || is_overflow_infinity (val2))
2049 /* If the operation overflowed but neither VAL1 nor VAL2 are
2050 overflown, return -INF or +INF depending on the operation
2051 and the combination of signs of the operands. */
2052 int sgn1 = tree_int_cst_sgn (val1);
2053 int sgn2 = tree_int_cst_sgn (val2);
2055 if (needs_overflow_infinity (TREE_TYPE (res))
2056 && !supports_overflow_infinity (TREE_TYPE (res)))
2059 /* We have to punt on adding infinities of different signs,
2060 since we can't tell what the sign of the result should be.
2061 Likewise for subtracting infinities of the same sign. */
2062 if (((code == PLUS_EXPR && sgn1 != sgn2)
2063 || (code == MINUS_EXPR && sgn1 == sgn2))
2064 && is_overflow_infinity (val1)
2065 && is_overflow_infinity (val2))
2068 /* Don't try to handle division or shifting of infinities. */
2069 if ((code == TRUNC_DIV_EXPR
2070 || code == FLOOR_DIV_EXPR
2071 || code == CEIL_DIV_EXPR
2072 || code == EXACT_DIV_EXPR
2073 || code == ROUND_DIV_EXPR
2074 || code == RSHIFT_EXPR)
2075 && (is_overflow_infinity (val1)
2076 || is_overflow_infinity (val2)))
2079 /* Notice that we only need to handle the restricted set of
2080 operations handled by extract_range_from_binary_expr.
2081 Among them, only multiplication, addition and subtraction
2082 can yield overflow without overflown operands because we
2083 are working with integral types only... except in the
2084 case VAL1 = -INF and VAL2 = -1 which overflows to +INF
2085 for division too. */
2087 /* For multiplication, the sign of the overflow is given
2088 by the comparison of the signs of the operands. */
2089 if ((code == MULT_EXPR && sgn1 == sgn2)
2090 /* For addition, the operands must be of the same sign
2091 to yield an overflow. Its sign is therefore that
2092 of one of the operands, for example the first. For
2093 infinite operands X + -INF is negative, not positive. */
2094 || (code == PLUS_EXPR
2096 ? !is_negative_overflow_infinity (val2)
2097 : is_positive_overflow_infinity (val2)))
2098 /* For subtraction, non-infinite operands must be of
2099 different signs to yield an overflow. Its sign is
2100 therefore that of the first operand or the opposite of
2101 that of the second operand. A first operand of 0 counts
2102 as positive here, for the corner case 0 - (-INF), which
2103 overflows, but must yield +INF. For infinite operands 0
2104 - INF is negative, not positive. */
2105 || (code == MINUS_EXPR
2107 ? !is_positive_overflow_infinity (val2)
2108 : is_negative_overflow_infinity (val2)))
2109 /* We only get in here with positive shift count, so the
2110 overflow direction is the same as the sign of val1.
2111 Actually rshift does not overflow at all, but we only
2112 handle the case of shifting overflowed -INF and +INF. */
2113 || (code == RSHIFT_EXPR
2115 /* For division, the only case is -INF / -1 = +INF. */
2116 || code == TRUNC_DIV_EXPR
2117 || code == FLOOR_DIV_EXPR
2118 || code == CEIL_DIV_EXPR
2119 || code == EXACT_DIV_EXPR
2120 || code == ROUND_DIV_EXPR)
2121 return (needs_overflow_infinity (TREE_TYPE (res))
2122 ? positive_overflow_infinity (TREE_TYPE (res))
2123 : TYPE_MAX_VALUE (TREE_TYPE (res)));
2125 return (needs_overflow_infinity (TREE_TYPE (res))
2126 ? negative_overflow_infinity (TREE_TYPE (res))
2127 : TYPE_MIN_VALUE (TREE_TYPE (res)));
2134 /* For range VR compute two double_int bitmasks. In *MAY_BE_NONZERO
2135 bitmask if some bit is unset, it means for all numbers in the range
2136 the bit is 0, otherwise it might be 0 or 1. In *MUST_BE_NONZERO
2137 bitmask if some bit is set, it means for all numbers in the range
2138 the bit is 1, otherwise it might be 0 or 1. */
2141 zero_nonzero_bits_from_vr (value_range_t *vr, double_int *may_be_nonzero,
2142 double_int *must_be_nonzero)
2144 may_be_nonzero->low = ALL_ONES;
2145 may_be_nonzero->high = ALL_ONES;
2146 must_be_nonzero->low = 0;
2147 must_be_nonzero->high = 0;
2148 if (range_int_cst_p (vr))
2150 if (range_int_cst_singleton_p (vr))
2152 *may_be_nonzero = tree_to_double_int (vr->min);
2153 *must_be_nonzero = *may_be_nonzero;
2155 else if (tree_int_cst_sgn (vr->min) >= 0)
2157 double_int dmin = tree_to_double_int (vr->min);
2158 double_int dmax = tree_to_double_int (vr->max);
2159 double_int xor_mask = double_int_xor (dmin, dmax);
2160 *may_be_nonzero = double_int_ior (dmin, dmax);
2161 *must_be_nonzero = double_int_and (dmin, dmax);
2162 if (xor_mask.high != 0)
2164 unsigned HOST_WIDE_INT mask
2165 = ((unsigned HOST_WIDE_INT) 1
2166 << floor_log2 (xor_mask.high)) - 1;
2167 may_be_nonzero->low = ALL_ONES;
2168 may_be_nonzero->high |= mask;
2169 must_be_nonzero->low = 0;
2170 must_be_nonzero->high &= ~mask;
2172 else if (xor_mask.low != 0)
2174 unsigned HOST_WIDE_INT mask
2175 = ((unsigned HOST_WIDE_INT) 1
2176 << floor_log2 (xor_mask.low)) - 1;
2177 may_be_nonzero->low |= mask;
2178 must_be_nonzero->low &= ~mask;
2187 /* Extract range information from a binary operation CODE based on
2188 the ranges of each of its operands, *VR0 and *VR1 with resulting
2189 type EXPR_TYPE. The resulting range is stored in *VR. */
2192 extract_range_from_binary_expr_1 (value_range_t *vr,
2193 enum tree_code code, tree expr_type,
2194 value_range_t *vr0_, value_range_t *vr1_)
2196 value_range_t vr0 = *vr0_, vr1 = *vr1_;
2197 enum value_range_type type;
2201 /* Not all binary expressions can be applied to ranges in a
2202 meaningful way. Handle only arithmetic operations. */
2203 if (code != PLUS_EXPR
2204 && code != MINUS_EXPR
2205 && code != POINTER_PLUS_EXPR
2206 && code != MULT_EXPR
2207 && code != TRUNC_DIV_EXPR
2208 && code != FLOOR_DIV_EXPR
2209 && code != CEIL_DIV_EXPR
2210 && code != EXACT_DIV_EXPR
2211 && code != ROUND_DIV_EXPR
2212 && code != TRUNC_MOD_EXPR
2213 && code != RSHIFT_EXPR
2216 && code != BIT_AND_EXPR
2217 && code != BIT_IOR_EXPR)
2219 set_value_range_to_varying (vr);
2223 /* If both ranges are UNDEFINED, so is the result. */
2224 if (vr0.type == VR_UNDEFINED && vr1.type == VR_UNDEFINED)
2226 set_value_range_to_undefined (vr);
2229 /* If one of the ranges is UNDEFINED drop it to VARYING for the following
2230 code. At some point we may want to special-case operations that
2231 have UNDEFINED result for all or some value-ranges of the not UNDEFINED
2233 else if (vr0.type == VR_UNDEFINED)
2234 set_value_range_to_varying (&vr0);
2235 else if (vr1.type == VR_UNDEFINED)
2236 set_value_range_to_varying (&vr1);
2238 /* The type of the resulting value range defaults to VR0.TYPE. */
2241 /* Refuse to operate on VARYING ranges, ranges of different kinds
2242 and symbolic ranges. As an exception, we allow BIT_AND_EXPR
2243 because we may be able to derive a useful range even if one of
2244 the operands is VR_VARYING or symbolic range. Similarly for
2245 divisions. TODO, we may be able to derive anti-ranges in
2247 if (code != BIT_AND_EXPR
2248 && code != BIT_IOR_EXPR
2249 && code != TRUNC_DIV_EXPR
2250 && code != FLOOR_DIV_EXPR
2251 && code != CEIL_DIV_EXPR
2252 && code != EXACT_DIV_EXPR
2253 && code != ROUND_DIV_EXPR
2254 && code != TRUNC_MOD_EXPR
2255 && (vr0.type == VR_VARYING
2256 || vr1.type == VR_VARYING
2257 || vr0.type != vr1.type
2258 || symbolic_range_p (&vr0)
2259 || symbolic_range_p (&vr1)))
2261 set_value_range_to_varying (vr);
2265 /* Now evaluate the expression to determine the new range. */
2266 if (POINTER_TYPE_P (expr_type))
2268 if (code == MIN_EXPR || code == MAX_EXPR)
2270 /* For MIN/MAX expressions with pointers, we only care about
2271 nullness, if both are non null, then the result is nonnull.
2272 If both are null, then the result is null. Otherwise they
2274 if (range_is_nonnull (&vr0) && range_is_nonnull (&vr1))
2275 set_value_range_to_nonnull (vr, expr_type);
2276 else if (range_is_null (&vr0) && range_is_null (&vr1))
2277 set_value_range_to_null (vr, expr_type);
2279 set_value_range_to_varying (vr);
2281 else if (code == POINTER_PLUS_EXPR)
2283 /* For pointer types, we are really only interested in asserting
2284 whether the expression evaluates to non-NULL. */
2285 if (range_is_nonnull (&vr0) || range_is_nonnull (&vr1))
2286 set_value_range_to_nonnull (vr, expr_type);
2287 else if (range_is_null (&vr0) && range_is_null (&vr1))
2288 set_value_range_to_null (vr, expr_type);
2290 set_value_range_to_varying (vr);
2292 else if (code == BIT_AND_EXPR)
2294 /* For pointer types, we are really only interested in asserting
2295 whether the expression evaluates to non-NULL. */
2296 if (range_is_nonnull (&vr0) && range_is_nonnull (&vr1))
2297 set_value_range_to_nonnull (vr, expr_type);
2298 else if (range_is_null (&vr0) || range_is_null (&vr1))
2299 set_value_range_to_null (vr, expr_type);
2301 set_value_range_to_varying (vr);
2304 set_value_range_to_varying (vr);
2309 /* For integer ranges, apply the operation to each end of the
2310 range and see what we end up with. */
2311 if (code == PLUS_EXPR
2313 || code == MAX_EXPR)
2315 /* If we have a PLUS_EXPR with two VR_ANTI_RANGEs, drop to
2316 VR_VARYING. It would take more effort to compute a precise
2317 range for such a case. For example, if we have op0 == 1 and
2318 op1 == -1 with their ranges both being ~[0,0], we would have
2319 op0 + op1 == 0, so we cannot claim that the sum is in ~[0,0].
2320 Note that we are guaranteed to have vr0.type == vr1.type at
2322 if (vr0.type == VR_ANTI_RANGE)
2324 if (code == PLUS_EXPR)
2326 set_value_range_to_varying (vr);
2329 /* For MIN_EXPR and MAX_EXPR with two VR_ANTI_RANGEs,
2330 the resulting VR_ANTI_RANGE is the same - intersection
2331 of the two ranges. */
2332 min = vrp_int_const_binop (MAX_EXPR, vr0.min, vr1.min);
2333 max = vrp_int_const_binop (MIN_EXPR, vr0.max, vr1.max);
2337 /* For operations that make the resulting range directly
2338 proportional to the original ranges, apply the operation to
2339 the same end of each range. */
2340 min = vrp_int_const_binop (code, vr0.min, vr1.min);
2341 max = vrp_int_const_binop (code, vr0.max, vr1.max);
2344 /* If both additions overflowed the range kind is still correct.
2345 This happens regularly with subtracting something in unsigned
2347 ??? See PR30318 for all the cases we do not handle. */
2348 if (code == PLUS_EXPR
2349 && (TREE_OVERFLOW (min) && !is_overflow_infinity (min))
2350 && (TREE_OVERFLOW (max) && !is_overflow_infinity (max)))
2352 min = build_int_cst_wide (TREE_TYPE (min),
2353 TREE_INT_CST_LOW (min),
2354 TREE_INT_CST_HIGH (min));
2355 max = build_int_cst_wide (TREE_TYPE (max),
2356 TREE_INT_CST_LOW (max),
2357 TREE_INT_CST_HIGH (max));
2360 else if (code == MULT_EXPR
2361 || code == TRUNC_DIV_EXPR
2362 || code == FLOOR_DIV_EXPR
2363 || code == CEIL_DIV_EXPR
2364 || code == EXACT_DIV_EXPR
2365 || code == ROUND_DIV_EXPR
2366 || code == RSHIFT_EXPR)
2372 /* If we have an unsigned MULT_EXPR with two VR_ANTI_RANGEs,
2373 drop to VR_VARYING. It would take more effort to compute a
2374 precise range for such a case. For example, if we have
2375 op0 == 65536 and op1 == 65536 with their ranges both being
2376 ~[0,0] on a 32-bit machine, we would have op0 * op1 == 0, so
2377 we cannot claim that the product is in ~[0,0]. Note that we
2378 are guaranteed to have vr0.type == vr1.type at this
2380 if (code == MULT_EXPR
2381 && vr0.type == VR_ANTI_RANGE
2382 && !TYPE_OVERFLOW_UNDEFINED (expr_type))
2384 set_value_range_to_varying (vr);
2388 /* If we have a RSHIFT_EXPR with any shift values outside [0..prec-1],
2389 then drop to VR_VARYING. Outside of this range we get undefined
2390 behavior from the shift operation. We cannot even trust
2391 SHIFT_COUNT_TRUNCATED at this stage, because that applies to rtl
2392 shifts, and the operation at the tree level may be widened. */
2393 if (code == RSHIFT_EXPR)
2395 if (vr1.type != VR_RANGE
2396 || !value_range_nonnegative_p (&vr1)
2397 || TREE_CODE (vr1.max) != INTEGER_CST
2398 || compare_tree_int (vr1.max,
2399 TYPE_PRECISION (expr_type) - 1) == 1)
2401 set_value_range_to_varying (vr);
2406 else if ((code == TRUNC_DIV_EXPR
2407 || code == FLOOR_DIV_EXPR
2408 || code == CEIL_DIV_EXPR
2409 || code == EXACT_DIV_EXPR
2410 || code == ROUND_DIV_EXPR)
2411 && (vr0.type != VR_RANGE || symbolic_range_p (&vr0)))
2413 /* For division, if op1 has VR_RANGE but op0 does not, something
2414 can be deduced just from that range. Say [min, max] / [4, max]
2415 gives [min / 4, max / 4] range. */
2416 if (vr1.type == VR_RANGE
2417 && !symbolic_range_p (&vr1)
2418 && !range_includes_zero_p (&vr1))
2420 vr0.type = type = VR_RANGE;
2421 vr0.min = vrp_val_min (expr_type);
2422 vr0.max = vrp_val_max (expr_type);
2426 set_value_range_to_varying (vr);
2431 /* For divisions, if flag_non_call_exceptions is true, we must
2432 not eliminate a division by zero. */
2433 if ((code == TRUNC_DIV_EXPR
2434 || code == FLOOR_DIV_EXPR
2435 || code == CEIL_DIV_EXPR
2436 || code == EXACT_DIV_EXPR
2437 || code == ROUND_DIV_EXPR)
2438 && cfun->can_throw_non_call_exceptions
2439 && (vr1.type != VR_RANGE
2440 || symbolic_range_p (&vr1)
2441 || range_includes_zero_p (&vr1)))
2443 set_value_range_to_varying (vr);
2447 /* For divisions, if op0 is VR_RANGE, we can deduce a range
2448 even if op1 is VR_VARYING, VR_ANTI_RANGE, symbolic or can
2450 if ((code == TRUNC_DIV_EXPR
2451 || code == FLOOR_DIV_EXPR
2452 || code == CEIL_DIV_EXPR
2453 || code == EXACT_DIV_EXPR
2454 || code == ROUND_DIV_EXPR)
2455 && vr0.type == VR_RANGE
2456 && (vr1.type != VR_RANGE
2457 || symbolic_range_p (&vr1)
2458 || range_includes_zero_p (&vr1)))
2460 tree zero = build_int_cst (TREE_TYPE (vr0.min), 0);
2466 if (TYPE_UNSIGNED (expr_type)
2467 || value_range_nonnegative_p (&vr1))
2469 /* For unsigned division or when divisor is known
2470 to be non-negative, the range has to cover
2471 all numbers from 0 to max for positive max
2472 and all numbers from min to 0 for negative min. */
2473 cmp = compare_values (vr0.max, zero);
2476 else if (cmp == 0 || cmp == 1)
2480 cmp = compare_values (vr0.min, zero);
2483 else if (cmp == 0 || cmp == -1)
2490 /* Otherwise the range is -max .. max or min .. -min
2491 depending on which bound is bigger in absolute value,
2492 as the division can change the sign. */
2493 abs_extent_range (vr, vr0.min, vr0.max);
2496 if (type == VR_VARYING)
2498 set_value_range_to_varying (vr);
2503 /* Multiplications and divisions are a bit tricky to handle,
2504 depending on the mix of signs we have in the two ranges, we
2505 need to operate on different values to get the minimum and
2506 maximum values for the new range. One approach is to figure
2507 out all the variations of range combinations and do the
2510 However, this involves several calls to compare_values and it
2511 is pretty convoluted. It's simpler to do the 4 operations
2512 (MIN0 OP MIN1, MIN0 OP MAX1, MAX0 OP MIN1 and MAX0 OP MAX0 OP
2513 MAX1) and then figure the smallest and largest values to form
2517 gcc_assert ((vr0.type == VR_RANGE
2518 || (code == MULT_EXPR && vr0.type == VR_ANTI_RANGE))
2519 && vr0.type == vr1.type);
2521 /* Compute the 4 cross operations. */
2523 val[0] = vrp_int_const_binop (code, vr0.min, vr1.min);
2524 if (val[0] == NULL_TREE)
2527 if (vr1.max == vr1.min)
2531 val[1] = vrp_int_const_binop (code, vr0.min, vr1.max);
2532 if (val[1] == NULL_TREE)
2536 if (vr0.max == vr0.min)
2540 val[2] = vrp_int_const_binop (code, vr0.max, vr1.min);
2541 if (val[2] == NULL_TREE)
2545 if (vr0.min == vr0.max || vr1.min == vr1.max)
2549 val[3] = vrp_int_const_binop (code, vr0.max, vr1.max);
2550 if (val[3] == NULL_TREE)
2556 set_value_range_to_varying (vr);
2560 /* Set MIN to the minimum of VAL[i] and MAX to the maximum
2564 for (i = 1; i < 4; i++)
2566 if (!is_gimple_min_invariant (min)
2567 || (TREE_OVERFLOW (min) && !is_overflow_infinity (min))
2568 || !is_gimple_min_invariant (max)
2569 || (TREE_OVERFLOW (max) && !is_overflow_infinity (max)))
2574 if (!is_gimple_min_invariant (val[i])
2575 || (TREE_OVERFLOW (val[i])
2576 && !is_overflow_infinity (val[i])))
2578 /* If we found an overflowed value, set MIN and MAX
2579 to it so that we set the resulting range to
2585 if (compare_values (val[i], min) == -1)
2588 if (compare_values (val[i], max) == 1)
2594 else if (code == TRUNC_MOD_EXPR)
2596 if (vr1.type != VR_RANGE
2597 || symbolic_range_p (&vr1)
2598 || range_includes_zero_p (&vr1)
2599 || vrp_val_is_min (vr1.min))
2601 set_value_range_to_varying (vr);
2605 /* Compute MAX <|vr1.min|, |vr1.max|> - 1. */
2606 max = fold_unary_to_constant (ABS_EXPR, expr_type, vr1.min);
2607 if (tree_int_cst_lt (max, vr1.max))
2609 max = int_const_binop (MINUS_EXPR, max, integer_one_node);
2610 /* If the dividend is non-negative the modulus will be
2611 non-negative as well. */
2612 if (TYPE_UNSIGNED (expr_type)
2613 || value_range_nonnegative_p (&vr0))
2614 min = build_int_cst (TREE_TYPE (max), 0);
2616 min = fold_unary_to_constant (NEGATE_EXPR, expr_type, max);
2618 else if (code == MINUS_EXPR)
2620 /* If we have a MINUS_EXPR with two VR_ANTI_RANGEs, drop to
2621 VR_VARYING. It would take more effort to compute a precise
2622 range for such a case. For example, if we have op0 == 1 and
2623 op1 == 1 with their ranges both being ~[0,0], we would have
2624 op0 - op1 == 0, so we cannot claim that the difference is in
2625 ~[0,0]. Note that we are guaranteed to have
2626 vr0.type == vr1.type at this point. */
2627 if (vr0.type == VR_ANTI_RANGE)
2629 set_value_range_to_varying (vr);
2633 /* For MINUS_EXPR, apply the operation to the opposite ends of
2635 min = vrp_int_const_binop (code, vr0.min, vr1.max);
2636 max = vrp_int_const_binop (code, vr0.max, vr1.min);
2638 else if (code == BIT_AND_EXPR || code == BIT_IOR_EXPR)
2640 bool int_cst_range0, int_cst_range1;
2641 double_int may_be_nonzero0, may_be_nonzero1;
2642 double_int must_be_nonzero0, must_be_nonzero1;
2644 int_cst_range0 = zero_nonzero_bits_from_vr (&vr0, &may_be_nonzero0,
2646 int_cst_range1 = zero_nonzero_bits_from_vr (&vr1, &may_be_nonzero1,
2650 if (code == BIT_AND_EXPR)
2652 min = double_int_to_tree (expr_type,
2653 double_int_and (must_be_nonzero0,
2655 max = double_int_to_tree (expr_type,
2656 double_int_and (may_be_nonzero0,
2658 if (tree_int_cst_sgn (min) < 0)
2660 if (tree_int_cst_sgn (max) < 0)
2662 if (int_cst_range0 && tree_int_cst_sgn (vr0.min) >= 0)
2664 if (min == NULL_TREE)
2665 min = build_int_cst (expr_type, 0);
2666 if (max == NULL_TREE || tree_int_cst_lt (vr0.max, max))
2669 if (int_cst_range1 && tree_int_cst_sgn (vr1.min) >= 0)
2671 if (min == NULL_TREE)
2672 min = build_int_cst (expr_type, 0);
2673 if (max == NULL_TREE || tree_int_cst_lt (vr1.max, max))
2677 else if (code == BIT_IOR_EXPR)
2679 min = double_int_to_tree (expr_type,
2680 double_int_ior (must_be_nonzero0,
2682 max = double_int_to_tree (expr_type,
2683 double_int_ior (may_be_nonzero0,
2685 if (tree_int_cst_sgn (max) < 0)
2689 if (tree_int_cst_sgn (min) < 0)
2692 min = vrp_int_const_binop (MAX_EXPR, min, vr0.min);
2695 min = vrp_int_const_binop (MAX_EXPR, min, vr1.min);
2699 set_value_range_to_varying (vr);
2706 /* If either MIN or MAX overflowed, then set the resulting range to
2707 VARYING. But we do accept an overflow infinity
2709 if (min == NULL_TREE
2710 || !is_gimple_min_invariant (min)
2711 || (TREE_OVERFLOW (min) && !is_overflow_infinity (min))
2713 || !is_gimple_min_invariant (max)
2714 || (TREE_OVERFLOW (max) && !is_overflow_infinity (max)))
2716 set_value_range_to_varying (vr);
2722 2) [-INF, +-INF(OVF)]
2723 3) [+-INF(OVF), +INF]
2724 4) [+-INF(OVF), +-INF(OVF)]
2725 We learn nothing when we have INF and INF(OVF) on both sides.
2726 Note that we do accept [-INF, -INF] and [+INF, +INF] without
2728 if ((vrp_val_is_min (min) || is_overflow_infinity (min))
2729 && (vrp_val_is_max (max) || is_overflow_infinity (max)))
2731 set_value_range_to_varying (vr);
2735 cmp = compare_values (min, max);
2736 if (cmp == -2 || cmp == 1)
2738 /* If the new range has its limits swapped around (MIN > MAX),
2739 then the operation caused one of them to wrap around, mark
2740 the new range VARYING. */
2741 set_value_range_to_varying (vr);
2744 set_value_range (vr, type, min, max, NULL);
2747 /* Extract range information from a binary expression OP0 CODE OP1 based on
2748 the ranges of each of its operands with resulting type EXPR_TYPE.
2749 The resulting range is stored in *VR. */
2752 extract_range_from_binary_expr (value_range_t *vr,
2753 enum tree_code code,
2754 tree expr_type, tree op0, tree op1)
2756 value_range_t vr0 = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
2757 value_range_t vr1 = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
2759 /* Get value ranges for each operand. For constant operands, create
2760 a new value range with the operand to simplify processing. */
2761 if (TREE_CODE (op0) == SSA_NAME)
2762 vr0 = *(get_value_range (op0));
2763 else if (is_gimple_min_invariant (op0))
2764 set_value_range_to_value (&vr0, op0, NULL);
2766 set_value_range_to_varying (&vr0);
2768 if (TREE_CODE (op1) == SSA_NAME)
2769 vr1 = *(get_value_range (op1));
2770 else if (is_gimple_min_invariant (op1))
2771 set_value_range_to_value (&vr1, op1, NULL);
2773 set_value_range_to_varying (&vr1);
2775 extract_range_from_binary_expr_1 (vr, code, expr_type, &vr0, &vr1);
2778 /* Extract range information from a unary expression EXPR based on
2779 the range of its operand and the expression code. */
2782 extract_range_from_unary_expr (value_range_t *vr, enum tree_code code,
2783 tree type, tree op0)
2787 value_range_t vr0 = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
2789 /* Refuse to operate on certain unary expressions for which we
2790 cannot easily determine a resulting range. */
2791 if (code == FIX_TRUNC_EXPR
2792 || code == FLOAT_EXPR
2793 || code == BIT_NOT_EXPR
2794 || code == CONJ_EXPR)
2796 /* We can still do constant propagation here. */
2797 if ((op0 = op_with_constant_singleton_value_range (op0)) != NULL_TREE)
2799 tree tem = fold_unary (code, type, op0);
2801 && is_gimple_min_invariant (tem)
2802 && !is_overflow_infinity (tem))
2804 set_value_range (vr, VR_RANGE, tem, tem, NULL);
2808 set_value_range_to_varying (vr);
2812 /* Get value ranges for the operand. For constant operands, create
2813 a new value range with the operand to simplify processing. */
2814 if (TREE_CODE (op0) == SSA_NAME)
2815 vr0 = *(get_value_range (op0));
2816 else if (is_gimple_min_invariant (op0))
2817 set_value_range_to_value (&vr0, op0, NULL);
2819 set_value_range_to_varying (&vr0);
2821 /* If VR0 is UNDEFINED, so is the result. */
2822 if (vr0.type == VR_UNDEFINED)
2824 set_value_range_to_undefined (vr);
2828 /* Refuse to operate on symbolic ranges, or if neither operand is
2829 a pointer or integral type. */
2830 if ((!INTEGRAL_TYPE_P (TREE_TYPE (op0))
2831 && !POINTER_TYPE_P (TREE_TYPE (op0)))
2832 || (vr0.type != VR_VARYING
2833 && symbolic_range_p (&vr0)))
2835 set_value_range_to_varying (vr);
2839 /* If the expression involves pointers, we are only interested in
2840 determining if it evaluates to NULL [0, 0] or non-NULL (~[0, 0]). */
2841 if (POINTER_TYPE_P (type) || POINTER_TYPE_P (TREE_TYPE (op0)))
2846 if (range_is_nonnull (&vr0)
2847 || (tree_unary_nonzero_warnv_p (code, type, op0, &sop)
2849 set_value_range_to_nonnull (vr, type);
2850 else if (range_is_null (&vr0))
2851 set_value_range_to_null (vr, type);
2853 set_value_range_to_varying (vr);
2858 /* Handle unary expressions on integer ranges. */
2859 if (CONVERT_EXPR_CODE_P (code)
2860 && INTEGRAL_TYPE_P (type)
2861 && INTEGRAL_TYPE_P (TREE_TYPE (op0)))
2863 tree inner_type = TREE_TYPE (op0);
2864 tree outer_type = type;
2866 /* If VR0 is varying and we increase the type precision, assume
2867 a full range for the following transformation. */
2868 if (vr0.type == VR_VARYING
2869 && TYPE_PRECISION (inner_type) < TYPE_PRECISION (outer_type))
2871 vr0.type = VR_RANGE;
2872 vr0.min = TYPE_MIN_VALUE (inner_type);
2873 vr0.max = TYPE_MAX_VALUE (inner_type);
2876 /* If VR0 is a constant range or anti-range and the conversion is
2877 not truncating we can convert the min and max values and
2878 canonicalize the resulting range. Otherwise we can do the
2879 conversion if the size of the range is less than what the
2880 precision of the target type can represent and the range is
2881 not an anti-range. */
2882 if ((vr0.type == VR_RANGE
2883 || vr0.type == VR_ANTI_RANGE)
2884 && TREE_CODE (vr0.min) == INTEGER_CST
2885 && TREE_CODE (vr0.max) == INTEGER_CST
2886 && (!is_overflow_infinity (vr0.min)
2887 || (vr0.type == VR_RANGE
2888 && TYPE_PRECISION (outer_type) > TYPE_PRECISION (inner_type)
2889 && needs_overflow_infinity (outer_type)
2890 && supports_overflow_infinity (outer_type)))
2891 && (!is_overflow_infinity (vr0.max)
2892 || (vr0.type == VR_RANGE
2893 && TYPE_PRECISION (outer_type) > TYPE_PRECISION (inner_type)
2894 && needs_overflow_infinity (outer_type)
2895 && supports_overflow_infinity (outer_type)))
2896 && (TYPE_PRECISION (outer_type) >= TYPE_PRECISION (inner_type)
2897 || (vr0.type == VR_RANGE
2898 && integer_zerop (int_const_binop (RSHIFT_EXPR,
2899 int_const_binop (MINUS_EXPR, vr0.max, vr0.min),
2900 size_int (TYPE_PRECISION (outer_type)))))))
2902 tree new_min, new_max;
2903 new_min = force_fit_type_double (outer_type,
2904 tree_to_double_int (vr0.min),
2906 new_max = force_fit_type_double (outer_type,
2907 tree_to_double_int (vr0.max),
2909 if (is_overflow_infinity (vr0.min))
2910 new_min = negative_overflow_infinity (outer_type);
2911 if (is_overflow_infinity (vr0.max))
2912 new_max = positive_overflow_infinity (outer_type);
2913 set_and_canonicalize_value_range (vr, vr0.type,
2914 new_min, new_max, NULL);
2918 set_value_range_to_varying (vr);
2922 /* Conversion of a VR_VARYING value to a wider type can result
2923 in a usable range. So wait until after we've handled conversions
2924 before dropping the result to VR_VARYING if we had a source
2925 operand that is VR_VARYING. */
2926 if (vr0.type == VR_VARYING)
2928 set_value_range_to_varying (vr);
2932 /* Apply the operation to each end of the range and see what we end
2934 if (code == NEGATE_EXPR
2935 && !TYPE_UNSIGNED (type))
2937 /* NEGATE_EXPR flips the range around. We need to treat
2938 TYPE_MIN_VALUE specially. */
2939 if (is_positive_overflow_infinity (vr0.max))
2940 min = negative_overflow_infinity (type);
2941 else if (is_negative_overflow_infinity (vr0.max))
2942 min = positive_overflow_infinity (type);
2943 else if (!vrp_val_is_min (vr0.max))
2944 min = fold_unary_to_constant (code, type, vr0.max);
2945 else if (needs_overflow_infinity (type))
2947 if (supports_overflow_infinity (type)
2948 && !is_overflow_infinity (vr0.min)
2949 && !vrp_val_is_min (vr0.min))
2950 min = positive_overflow_infinity (type);
2953 set_value_range_to_varying (vr);
2958 min = TYPE_MIN_VALUE (type);
2960 if (is_positive_overflow_infinity (vr0.min))
2961 max = negative_overflow_infinity (type);
2962 else if (is_negative_overflow_infinity (vr0.min))
2963 max = positive_overflow_infinity (type);
2964 else if (!vrp_val_is_min (vr0.min))
2965 max = fold_unary_to_constant (code, type, vr0.min);
2966 else if (needs_overflow_infinity (type))
2968 if (supports_overflow_infinity (type))
2969 max = positive_overflow_infinity (type);
2972 set_value_range_to_varying (vr);
2977 max = TYPE_MIN_VALUE (type);
2979 else if (code == NEGATE_EXPR
2980 && TYPE_UNSIGNED (type))
2982 if (!range_includes_zero_p (&vr0))
2984 max = fold_unary_to_constant (code, type, vr0.min);
2985 min = fold_unary_to_constant (code, type, vr0.max);
2989 if (range_is_null (&vr0))
2990 set_value_range_to_null (vr, type);
2992 set_value_range_to_varying (vr);
2996 else if (code == ABS_EXPR
2997 && !TYPE_UNSIGNED (type))
2999 /* -TYPE_MIN_VALUE = TYPE_MIN_VALUE with flag_wrapv so we can't get a
3001 if (!TYPE_OVERFLOW_UNDEFINED (type)
3002 && ((vr0.type == VR_RANGE
3003 && vrp_val_is_min (vr0.min))
3004 || (vr0.type == VR_ANTI_RANGE
3005 && !vrp_val_is_min (vr0.min)
3006 && !range_includes_zero_p (&vr0))))
3008 set_value_range_to_varying (vr);
3012 /* ABS_EXPR may flip the range around, if the original range
3013 included negative values. */
3014 if (is_overflow_infinity (vr0.min))
3015 min = positive_overflow_infinity (type);
3016 else if (!vrp_val_is_min (vr0.min))
3017 min = fold_unary_to_constant (code, type, vr0.min);
3018 else if (!needs_overflow_infinity (type))
3019 min = TYPE_MAX_VALUE (type);
3020 else if (supports_overflow_infinity (type))
3021 min = positive_overflow_infinity (type);
3024 set_value_range_to_varying (vr);
3028 if (is_overflow_infinity (vr0.max))
3029 max = positive_overflow_infinity (type);
3030 else if (!vrp_val_is_min (vr0.max))
3031 max = fold_unary_to_constant (code, type, vr0.max);
3032 else if (!needs_overflow_infinity (type))
3033 max = TYPE_MAX_VALUE (type);
3034 else if (supports_overflow_infinity (type)
3035 /* We shouldn't generate [+INF, +INF] as set_value_range
3036 doesn't like this and ICEs. */
3037 && !is_positive_overflow_infinity (min))
3038 max = positive_overflow_infinity (type);
3041 set_value_range_to_varying (vr);
3045 cmp = compare_values (min, max);
3047 /* If a VR_ANTI_RANGEs contains zero, then we have
3048 ~[-INF, min(MIN, MAX)]. */
3049 if (vr0.type == VR_ANTI_RANGE)
3051 if (range_includes_zero_p (&vr0))
3053 /* Take the lower of the two values. */
3057 /* Create ~[-INF, min (abs(MIN), abs(MAX))]
3058 or ~[-INF + 1, min (abs(MIN), abs(MAX))] when
3059 flag_wrapv is set and the original anti-range doesn't include
3060 TYPE_MIN_VALUE, remember -TYPE_MIN_VALUE = TYPE_MIN_VALUE. */
3061 if (TYPE_OVERFLOW_WRAPS (type))
3063 tree type_min_value = TYPE_MIN_VALUE (type);
3065 min = (vr0.min != type_min_value
3066 ? int_const_binop (PLUS_EXPR, type_min_value,
3072 if (overflow_infinity_range_p (&vr0))
3073 min = negative_overflow_infinity (type);
3075 min = TYPE_MIN_VALUE (type);
3080 /* All else has failed, so create the range [0, INF], even for
3081 flag_wrapv since TYPE_MIN_VALUE is in the original
3083 vr0.type = VR_RANGE;
3084 min = build_int_cst (type, 0);
3085 if (needs_overflow_infinity (type))
3087 if (supports_overflow_infinity (type))
3088 max = positive_overflow_infinity (type);
3091 set_value_range_to_varying (vr);
3096 max = TYPE_MAX_VALUE (type);
3100 /* If the range contains zero then we know that the minimum value in the
3101 range will be zero. */
3102 else if (range_includes_zero_p (&vr0))
3106 min = build_int_cst (type, 0);
3110 /* If the range was reversed, swap MIN and MAX. */
3121 /* Otherwise, operate on each end of the range. */
3122 min = fold_unary_to_constant (code, type, vr0.min);
3123 max = fold_unary_to_constant (code, type, vr0.max);
3125 if (needs_overflow_infinity (type))
3127 gcc_assert (code != NEGATE_EXPR && code != ABS_EXPR);
3129 /* If both sides have overflowed, we don't know
3131 if ((is_overflow_infinity (vr0.min)
3132 || TREE_OVERFLOW (min))
3133 && (is_overflow_infinity (vr0.max)
3134 || TREE_OVERFLOW (max)))
3136 set_value_range_to_varying (vr);
3140 if (is_overflow_infinity (vr0.min))
3142 else if (TREE_OVERFLOW (min))
3144 if (supports_overflow_infinity (type))
3145 min = (tree_int_cst_sgn (min) >= 0
3146 ? positive_overflow_infinity (TREE_TYPE (min))
3147 : negative_overflow_infinity (TREE_TYPE (min)));
3150 set_value_range_to_varying (vr);
3155 if (is_overflow_infinity (vr0.max))
3157 else if (TREE_OVERFLOW (max))
3159 if (supports_overflow_infinity (type))
3160 max = (tree_int_cst_sgn (max) >= 0
3161 ? positive_overflow_infinity (TREE_TYPE (max))
3162 : negative_overflow_infinity (TREE_TYPE (max)));
3165 set_value_range_to_varying (vr);
3172 cmp = compare_values (min, max);
3173 if (cmp == -2 || cmp == 1)
3175 /* If the new range has its limits swapped around (MIN > MAX),
3176 then the operation caused one of them to wrap around, mark
3177 the new range VARYING. */
3178 set_value_range_to_varying (vr);
3181 set_value_range (vr, vr0.type, min, max, NULL);
3185 /* Extract range information from a conditional expression EXPR based on
3186 the ranges of each of its operands and the expression code. */
3189 extract_range_from_cond_expr (value_range_t *vr, tree expr)
3192 value_range_t vr0 = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
3193 value_range_t vr1 = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
3195 /* Get value ranges for each operand. For constant operands, create
3196 a new value range with the operand to simplify processing. */
3197 op0 = COND_EXPR_THEN (expr);
3198 if (TREE_CODE (op0) == SSA_NAME)
3199 vr0 = *(get_value_range (op0));
3200 else if (is_gimple_min_invariant (op0))
3201 set_value_range_to_value (&vr0, op0, NULL);
3203 set_value_range_to_varying (&vr0);
3205 op1 = COND_EXPR_ELSE (expr);
3206 if (TREE_CODE (op1) == SSA_NAME)
3207 vr1 = *(get_value_range (op1));
3208 else if (is_gimple_min_invariant (op1))
3209 set_value_range_to_value (&vr1, op1, NULL);
3211 set_value_range_to_varying (&vr1);
3213 /* The resulting value range is the union of the operand ranges */
3214 vrp_meet (&vr0, &vr1);
3215 copy_value_range (vr, &vr0);
3219 /* Extract range information from a comparison expression EXPR based
3220 on the range of its operand and the expression code. */
3223 extract_range_from_comparison (value_range_t *vr, enum tree_code code,
3224 tree type, tree op0, tree op1)
3229 val = vrp_evaluate_conditional_warnv_with_ops (code, op0, op1, false, &sop,
3232 /* A disadvantage of using a special infinity as an overflow
3233 representation is that we lose the ability to record overflow
3234 when we don't have an infinity. So we have to ignore a result
3235 which relies on overflow. */
3237 if (val && !is_overflow_infinity (val) && !sop)
3239 /* Since this expression was found on the RHS of an assignment,
3240 its type may be different from _Bool. Convert VAL to EXPR's
3242 val = fold_convert (type, val);
3243 if (is_gimple_min_invariant (val))
3244 set_value_range_to_value (vr, val, vr->equiv);
3246 set_value_range (vr, VR_RANGE, val, val, vr->equiv);
3249 /* The result of a comparison is always true or false. */
3250 set_value_range_to_truthvalue (vr, type);
3253 /* Try to derive a nonnegative or nonzero range out of STMT relying
3254 primarily on generic routines in fold in conjunction with range data.
3255 Store the result in *VR */
3258 extract_range_basic (value_range_t *vr, gimple stmt)
3261 tree type = gimple_expr_type (stmt);
3263 if (INTEGRAL_TYPE_P (type)
3264 && gimple_stmt_nonnegative_warnv_p (stmt, &sop))
3265 set_value_range_to_nonnegative (vr, type,
3266 sop || stmt_overflow_infinity (stmt));
3267 else if (vrp_stmt_computes_nonzero (stmt, &sop)
3269 set_value_range_to_nonnull (vr, type);
3271 set_value_range_to_varying (vr);
3275 /* Try to compute a useful range out of assignment STMT and store it
3279 extract_range_from_assignment (value_range_t *vr, gimple stmt)
3281 enum tree_code code = gimple_assign_rhs_code (stmt);
3283 if (code == ASSERT_EXPR)
3284 extract_range_from_assert (vr, gimple_assign_rhs1 (stmt));
3285 else if (code == SSA_NAME)
3286 extract_range_from_ssa_name (vr, gimple_assign_rhs1 (stmt));
3287 else if (TREE_CODE_CLASS (code) == tcc_binary)
3288 extract_range_from_binary_expr (vr, gimple_assign_rhs_code (stmt),
3289 gimple_expr_type (stmt),
3290 gimple_assign_rhs1 (stmt),
3291 gimple_assign_rhs2 (stmt));
3292 else if (TREE_CODE_CLASS (code) == tcc_unary)
3293 extract_range_from_unary_expr (vr, gimple_assign_rhs_code (stmt),
3294 gimple_expr_type (stmt),
3295 gimple_assign_rhs1 (stmt));
3296 else if (code == COND_EXPR)
3297 extract_range_from_cond_expr (vr, gimple_assign_rhs1 (stmt));
3298 else if (TREE_CODE_CLASS (code) == tcc_comparison)
3299 extract_range_from_comparison (vr, gimple_assign_rhs_code (stmt),
3300 gimple_expr_type (stmt),
3301 gimple_assign_rhs1 (stmt),
3302 gimple_assign_rhs2 (stmt));
3303 else if (get_gimple_rhs_class (code) == GIMPLE_SINGLE_RHS
3304 && is_gimple_min_invariant (gimple_assign_rhs1 (stmt)))
3305 set_value_range_to_value (vr, gimple_assign_rhs1 (stmt), NULL);
3307 set_value_range_to_varying (vr);
3309 if (vr->type == VR_VARYING)
3310 extract_range_basic (vr, stmt);
3313 /* Given a range VR, a LOOP and a variable VAR, determine whether it
3314 would be profitable to adjust VR using scalar evolution information
3315 for VAR. If so, update VR with the new limits. */
3318 adjust_range_with_scev (value_range_t *vr, struct loop *loop,
3319 gimple stmt, tree var)
3321 tree init, step, chrec, tmin, tmax, min, max, type, tem;
3322 enum ev_direction dir;
3324 /* TODO. Don't adjust anti-ranges. An anti-range may provide
3325 better opportunities than a regular range, but I'm not sure. */
3326 if (vr->type == VR_ANTI_RANGE)
3329 chrec = instantiate_parameters (loop, analyze_scalar_evolution (loop, var));
3331 /* Like in PR19590, scev can return a constant function. */
3332 if (is_gimple_min_invariant (chrec))
3334 set_value_range_to_value (vr, chrec, vr->equiv);
3338 if (TREE_CODE (chrec) != POLYNOMIAL_CHREC)
3341 init = initial_condition_in_loop_num (chrec, loop->num);
3342 tem = op_with_constant_singleton_value_range (init);
3345 step = evolution_part_in_loop_num (chrec, loop->num);
3346 tem = op_with_constant_singleton_value_range (step);
3350 /* If STEP is symbolic, we can't know whether INIT will be the
3351 minimum or maximum value in the range. Also, unless INIT is
3352 a simple expression, compare_values and possibly other functions
3353 in tree-vrp won't be able to handle it. */
3354 if (step == NULL_TREE
3355 || !is_gimple_min_invariant (step)
3356 || !valid_value_p (init))
3359 dir = scev_direction (chrec);
3360 if (/* Do not adjust ranges if we do not know whether the iv increases
3361 or decreases, ... */
3362 dir == EV_DIR_UNKNOWN
3363 /* ... or if it may wrap. */
3364 || scev_probably_wraps_p (init, step, stmt, get_chrec_loop (chrec),
3368 /* We use TYPE_MIN_VALUE and TYPE_MAX_VALUE here instead of
3369 negative_overflow_infinity and positive_overflow_infinity,
3370 because we have concluded that the loop probably does not
3373 type = TREE_TYPE (var);
3374 if (POINTER_TYPE_P (type) || !TYPE_MIN_VALUE (type))
3375 tmin = lower_bound_in_type (type, type);
3377 tmin = TYPE_MIN_VALUE (type);
3378 if (POINTER_TYPE_P (type) || !TYPE_MAX_VALUE (type))
3379 tmax = upper_bound_in_type (type, type);
3381 tmax = TYPE_MAX_VALUE (type);
3383 /* Try to use estimated number of iterations for the loop to constrain the
3384 final value in the evolution. */
3385 if (TREE_CODE (step) == INTEGER_CST
3386 && is_gimple_val (init)
3387 && (TREE_CODE (init) != SSA_NAME
3388 || get_value_range (init)->type == VR_RANGE))
3392 if (estimated_loop_iterations (loop, true, &nit))
3394 value_range_t maxvr = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
3396 bool unsigned_p = TYPE_UNSIGNED (TREE_TYPE (step));
3399 dtmp = double_int_mul_with_sign (tree_to_double_int (step), nit,
3400 unsigned_p, &overflow);
3401 /* If the multiplication overflowed we can't do a meaningful
3402 adjustment. Likewise if the result doesn't fit in the type
3403 of the induction variable. For a signed type we have to
3404 check whether the result has the expected signedness which
3405 is that of the step as number of iterations is unsigned. */
3407 && double_int_fits_to_tree_p (TREE_TYPE (init), dtmp)
3409 || ((dtmp.high ^ TREE_INT_CST_HIGH (step)) >= 0)))
3411 tem = double_int_to_tree (TREE_TYPE (init), dtmp);
3412 extract_range_from_binary_expr (&maxvr, PLUS_EXPR,
3413 TREE_TYPE (init), init, tem);
3414 /* Likewise if the addition did. */
3415 if (maxvr.type == VR_RANGE)
3424 if (vr->type == VR_VARYING || vr->type == VR_UNDEFINED)
3429 /* For VARYING or UNDEFINED ranges, just about anything we get
3430 from scalar evolutions should be better. */
3432 if (dir == EV_DIR_DECREASES)
3437 /* If we would create an invalid range, then just assume we
3438 know absolutely nothing. This may be over-conservative,
3439 but it's clearly safe, and should happen only in unreachable
3440 parts of code, or for invalid programs. */
3441 if (compare_values (min, max) == 1)
3444 set_value_range (vr, VR_RANGE, min, max, vr->equiv);
3446 else if (vr->type == VR_RANGE)
3451 if (dir == EV_DIR_DECREASES)
3453 /* INIT is the maximum value. If INIT is lower than VR->MAX
3454 but no smaller than VR->MIN, set VR->MAX to INIT. */
3455 if (compare_values (init, max) == -1)
3458 /* According to the loop information, the variable does not
3459 overflow. If we think it does, probably because of an
3460 overflow due to arithmetic on a different INF value,
3462 if (is_negative_overflow_infinity (min)
3463 || compare_values (min, tmin) == -1)
3469 /* If INIT is bigger than VR->MIN, set VR->MIN to INIT. */
3470 if (compare_values (init, min) == 1)
3473 if (is_positive_overflow_infinity (max)
3474 || compare_values (tmax, max) == -1)
3478 /* If we just created an invalid range with the minimum
3479 greater than the maximum, we fail conservatively.
3480 This should happen only in unreachable
3481 parts of code, or for invalid programs. */
3482 if (compare_values (min, max) == 1)
3485 set_value_range (vr, VR_RANGE, min, max, vr->equiv);
3489 /* Return true if VAR may overflow at STMT. This checks any available
3490 loop information to see if we can determine that VAR does not
3494 vrp_var_may_overflow (tree var, gimple stmt)
3497 tree chrec, init, step;
3499 if (current_loops == NULL)
3502 l = loop_containing_stmt (stmt);
3507 chrec = instantiate_parameters (l, analyze_scalar_evolution (l, var));
3508 if (TREE_CODE (chrec) != POLYNOMIAL_CHREC)
3511 init = initial_condition_in_loop_num (chrec, l->num);
3512 step = evolution_part_in_loop_num (chrec, l->num);
3514 if (step == NULL_TREE
3515 || !is_gimple_min_invariant (step)
3516 || !valid_value_p (init))
3519 /* If we get here, we know something useful about VAR based on the
3520 loop information. If it wraps, it may overflow. */
3522 if (scev_probably_wraps_p (init, step, stmt, get_chrec_loop (chrec),
3526 if (dump_file && (dump_flags & TDF_DETAILS) != 0)
3528 print_generic_expr (dump_file, var, 0);
3529 fprintf (dump_file, ": loop information indicates does not overflow\n");
3536 /* Given two numeric value ranges VR0, VR1 and a comparison code COMP:
3538 - Return BOOLEAN_TRUE_NODE if VR0 COMP VR1 always returns true for
3539 all the values in the ranges.
3541 - Return BOOLEAN_FALSE_NODE if the comparison always returns false.
3543 - Return NULL_TREE if it is not always possible to determine the
3544 value of the comparison.
3546 Also set *STRICT_OVERFLOW_P to indicate whether a range with an
3547 overflow infinity was used in the test. */
3551 compare_ranges (enum tree_code comp, value_range_t *vr0, value_range_t *vr1,
3552 bool *strict_overflow_p)
3554 /* VARYING or UNDEFINED ranges cannot be compared. */
3555 if (vr0->type == VR_VARYING
3556 || vr0->type == VR_UNDEFINED
3557 || vr1->type == VR_VARYING
3558 || vr1->type == VR_UNDEFINED)
3561 /* Anti-ranges need to be handled separately. */
3562 if (vr0->type == VR_ANTI_RANGE || vr1->type == VR_ANTI_RANGE)
3564 /* If both are anti-ranges, then we cannot compute any
3566 if (vr0->type == VR_ANTI_RANGE && vr1->type == VR_ANTI_RANGE)
3569 /* These comparisons are never statically computable. */
3576 /* Equality can be computed only between a range and an
3577 anti-range. ~[VAL1, VAL2] == [VAL1, VAL2] is always false. */
3578 if (vr0->type == VR_RANGE)
3580 /* To simplify processing, make VR0 the anti-range. */
3581 value_range_t *tmp = vr0;
3586 gcc_assert (comp == NE_EXPR || comp == EQ_EXPR);
3588 if (compare_values_warnv (vr0->min, vr1->min, strict_overflow_p) == 0
3589 && compare_values_warnv (vr0->max, vr1->max, strict_overflow_p) == 0)
3590 return (comp == NE_EXPR) ? boolean_true_node : boolean_false_node;
3595 if (!usable_range_p (vr0, strict_overflow_p)
3596 || !usable_range_p (vr1, strict_overflow_p))
3599 /* Simplify processing. If COMP is GT_EXPR or GE_EXPR, switch the
3600 operands around and change the comparison code. */
3601 if (comp == GT_EXPR || comp == GE_EXPR)
3604 comp = (comp == GT_EXPR) ? LT_EXPR : LE_EXPR;
3610 if (comp == EQ_EXPR)
3612 /* Equality may only be computed if both ranges represent
3613 exactly one value. */
3614 if (compare_values_warnv (vr0->min, vr0->max, strict_overflow_p) == 0
3615 && compare_values_warnv (vr1->min, vr1->max, strict_overflow_p) == 0)
3617 int cmp_min = compare_values_warnv (vr0->min, vr1->min,
3619 int cmp_max = compare_values_warnv (vr0->max, vr1->max,
3621 if (cmp_min == 0 && cmp_max == 0)
3622 return boolean_true_node;
3623 else if (cmp_min != -2 && cmp_max != -2)
3624 return boolean_false_node;
3626 /* If [V0_MIN, V1_MAX] < [V1_MIN, V1_MAX] then V0 != V1. */
3627 else if (compare_values_warnv (vr0->min, vr1->max,
3628 strict_overflow_p) == 1
3629 || compare_values_warnv (vr1->min, vr0->max,
3630 strict_overflow_p) == 1)
3631 return boolean_false_node;
3635 else if (comp == NE_EXPR)
3639 /* If VR0 is completely to the left or completely to the right
3640 of VR1, they are always different. Notice that we need to
3641 make sure that both comparisons yield similar results to
3642 avoid comparing values that cannot be compared at
3644 cmp1 = compare_values_warnv (vr0->max, vr1->min, strict_overflow_p);
3645 cmp2 = compare_values_warnv (vr0->min, vr1->max, strict_overflow_p);
3646 if ((cmp1 == -1 && cmp2 == -1) || (cmp1 == 1 && cmp2 == 1))
3647 return boolean_true_node;
3649 /* If VR0 and VR1 represent a single value and are identical,
3651 else if (compare_values_warnv (vr0->min, vr0->max,
3652 strict_overflow_p) == 0
3653 && compare_values_warnv (vr1->min, vr1->max,
3654 strict_overflow_p) == 0
3655 && compare_values_warnv (vr0->min, vr1->min,
3656 strict_overflow_p) == 0
3657 && compare_values_warnv (vr0->max, vr1->max,
3658 strict_overflow_p) == 0)
3659 return boolean_false_node;
3661 /* Otherwise, they may or may not be different. */
3665 else if (comp == LT_EXPR || comp == LE_EXPR)
3669 /* If VR0 is to the left of VR1, return true. */
3670 tst = compare_values_warnv (vr0->max, vr1->min, strict_overflow_p);
3671 if ((comp == LT_EXPR && tst == -1)
3672 || (comp == LE_EXPR && (tst == -1 || tst == 0)))
3674 if (overflow_infinity_range_p (vr0)
3675 || overflow_infinity_range_p (vr1))
3676 *strict_overflow_p = true;
3677 return boolean_true_node;
3680 /* If VR0 is to the right of VR1, return false. */
3681 tst = compare_values_warnv (vr0->min, vr1->max, strict_overflow_p);
3682 if ((comp == LT_EXPR && (tst == 0 || tst == 1))
3683 || (comp == LE_EXPR && tst == 1))
3685 if (overflow_infinity_range_p (vr0)
3686 || overflow_infinity_range_p (vr1))
3687 *strict_overflow_p = true;
3688 return boolean_false_node;
3691 /* Otherwise, we don't know. */
3699 /* Given a value range VR, a value VAL and a comparison code COMP, return
3700 BOOLEAN_TRUE_NODE if VR COMP VAL always returns true for all the
3701 values in VR. Return BOOLEAN_FALSE_NODE if the comparison
3702 always returns false. Return NULL_TREE if it is not always
3703 possible to determine the value of the comparison. Also set
3704 *STRICT_OVERFLOW_P to indicate whether a range with an overflow
3705 infinity was used in the test. */
3708 compare_range_with_value (enum tree_code comp, value_range_t *vr, tree val,
3709 bool *strict_overflow_p)
3711 if (vr->type == VR_VARYING || vr->type == VR_UNDEFINED)
3714 /* Anti-ranges need to be handled separately. */
3715 if (vr->type == VR_ANTI_RANGE)
3717 /* For anti-ranges, the only predicates that we can compute at
3718 compile time are equality and inequality. */
3725 /* ~[VAL_1, VAL_2] OP VAL is known if VAL_1 <= VAL <= VAL_2. */
3726 if (value_inside_range (val, vr) == 1)
3727 return (comp == NE_EXPR) ? boolean_true_node : boolean_false_node;
3732 if (!usable_range_p (vr, strict_overflow_p))
3735 if (comp == EQ_EXPR)
3737 /* EQ_EXPR may only be computed if VR represents exactly
3739 if (compare_values_warnv (vr->min, vr->max, strict_overflow_p) == 0)
3741 int cmp = compare_values_warnv (vr->min, val, strict_overflow_p);
3743 return boolean_true_node;
3744 else if (cmp == -1 || cmp == 1 || cmp == 2)
3745 return boolean_false_node;
3747 else if (compare_values_warnv (val, vr->min, strict_overflow_p) == -1
3748 || compare_values_warnv (vr->max, val, strict_overflow_p) == -1)
3749 return boolean_false_node;
3753 else if (comp == NE_EXPR)
3755 /* If VAL is not inside VR, then they are always different. */
3756 if (compare_values_warnv (vr->max, val, strict_overflow_p) == -1
3757 || compare_values_warnv (vr->min, val, strict_overflow_p) == 1)
3758 return boolean_true_node;
3760 /* If VR represents exactly one value equal to VAL, then return
3762 if (compare_values_warnv (vr->min, vr->max, strict_overflow_p) == 0
3763 && compare_values_warnv (vr->min, val, strict_overflow_p) == 0)
3764 return boolean_false_node;
3766 /* Otherwise, they may or may not be different. */
3769 else if (comp == LT_EXPR || comp == LE_EXPR)
3773 /* If VR is to the left of VAL, return true. */
3774 tst = compare_values_warnv (vr->max, val, strict_overflow_p);
3775 if ((comp == LT_EXPR && tst == -1)
3776 || (comp == LE_EXPR && (tst == -1 || tst == 0)))
3778 if (overflow_infinity_range_p (vr))
3779 *strict_overflow_p = true;
3780 return boolean_true_node;
3783 /* If VR is to the right of VAL, return false. */
3784 tst = compare_values_warnv (vr->min, val, strict_overflow_p);
3785 if ((comp == LT_EXPR && (tst == 0 || tst == 1))
3786 || (comp == LE_EXPR && tst == 1))
3788 if (overflow_infinity_range_p (vr))
3789 *strict_overflow_p = true;
3790 return boolean_false_node;
3793 /* Otherwise, we don't know. */
3796 else if (comp == GT_EXPR || comp == GE_EXPR)
3800 /* If VR is to the right of VAL, return true. */
3801 tst = compare_values_warnv (vr->min, val, strict_overflow_p);
3802 if ((comp == GT_EXPR && tst == 1)
3803 || (comp == GE_EXPR && (tst == 0 || tst == 1)))
3805 if (overflow_infinity_range_p (vr))
3806 *strict_overflow_p = true;
3807 return boolean_true_node;
3810 /* If VR is to the left of VAL, return false. */
3811 tst = compare_values_warnv (vr->max, val, strict_overflow_p);
3812 if ((comp == GT_EXPR && (tst == -1 || tst == 0))
3813 || (comp == GE_EXPR && tst == -1))
3815 if (overflow_infinity_range_p (vr))
3816 *strict_overflow_p = true;
3817 return boolean_false_node;
3820 /* Otherwise, we don't know. */
3828 /* Debugging dumps. */
3830 void dump_value_range (FILE *, value_range_t *);
3831 void debug_value_range (value_range_t *);
3832 void dump_all_value_ranges (FILE *);
3833 void debug_all_value_ranges (void);
3834 void dump_vr_equiv (FILE *, bitmap);
3835 void debug_vr_equiv (bitmap);
3838 /* Dump value range VR to FILE. */
3841 dump_value_range (FILE *file, value_range_t *vr)
3844 fprintf (file, "[]");
3845 else if (vr->type == VR_UNDEFINED)
3846 fprintf (file, "UNDEFINED");
3847 else if (vr->type == VR_RANGE || vr->type == VR_ANTI_RANGE)
3849 tree type = TREE_TYPE (vr->min);
3851 fprintf (file, "%s[", (vr->type == VR_ANTI_RANGE) ? "~" : "");
3853 if (is_negative_overflow_infinity (vr->min))
3854 fprintf (file, "-INF(OVF)");
3855 else if (INTEGRAL_TYPE_P (type)
3856 && !TYPE_UNSIGNED (type)
3857 && vrp_val_is_min (vr->min))
3858 fprintf (file, "-INF");
3860 print_generic_expr (file, vr->min, 0);
3862 fprintf (file, ", ");
3864 if (is_positive_overflow_infinity (vr->max))
3865 fprintf (file, "+INF(OVF)");
3866 else if (INTEGRAL_TYPE_P (type)
3867 && vrp_val_is_max (vr->max))
3868 fprintf (file, "+INF");
3870 print_generic_expr (file, vr->max, 0);
3872 fprintf (file, "]");
3879 fprintf (file, " EQUIVALENCES: { ");
3881 EXECUTE_IF_SET_IN_BITMAP (vr->equiv, 0, i, bi)
3883 print_generic_expr (file, ssa_name (i), 0);
3884 fprintf (file, " ");
3888 fprintf (file, "} (%u elements)", c);
3891 else if (vr->type == VR_VARYING)
3892 fprintf (file, "VARYING");
3894 fprintf (file, "INVALID RANGE");
3898 /* Dump value range VR to stderr. */
3901 debug_value_range (value_range_t *vr)
3903 dump_value_range (stderr, vr);
3904 fprintf (stderr, "\n");
3908 /* Dump value ranges of all SSA_NAMEs to FILE. */
3911 dump_all_value_ranges (FILE *file)
3915 for (i = 0; i < num_vr_values; i++)
3919 print_generic_expr (file, ssa_name (i), 0);
3920 fprintf (file, ": ");
3921 dump_value_range (file, vr_value[i]);
3922 fprintf (file, "\n");
3926 fprintf (file, "\n");
3930 /* Dump all value ranges to stderr. */
3933 debug_all_value_ranges (void)
3935 dump_all_value_ranges (stderr);
3939 /* Given a COND_EXPR COND of the form 'V OP W', and an SSA name V,
3940 create a new SSA name N and return the assertion assignment
3941 'V = ASSERT_EXPR <V, V OP W>'. */
3944 build_assert_expr_for (tree cond, tree v)
3949 gcc_assert (TREE_CODE (v) == SSA_NAME);
3950 n = duplicate_ssa_name (v, NULL);
3952 if (COMPARISON_CLASS_P (cond))
3954 tree a = build2 (ASSERT_EXPR, TREE_TYPE (v), v, cond);
3955 assertion = gimple_build_assign (n, a);
3957 else if (TREE_CODE (cond) == SSA_NAME)
3959 /* Given V, build the assignment N = true. */
3960 gcc_assert (v == cond);
3961 assertion = gimple_build_assign (n, boolean_true_node);
3966 SSA_NAME_DEF_STMT (n) = assertion;
3968 /* The new ASSERT_EXPR, creates a new SSA name that replaces the
3969 operand of the ASSERT_EXPR. Register the new name and the old one
3970 in the replacement table so that we can fix the SSA web after
3971 adding all the ASSERT_EXPRs. */
3972 register_new_name_mapping (n, v);
3978 /* Return false if EXPR is a predicate expression involving floating
3982 fp_predicate (gimple stmt)
3984 GIMPLE_CHECK (stmt, GIMPLE_COND);
3986 return FLOAT_TYPE_P (TREE_TYPE (gimple_cond_lhs (stmt)));
3990 /* If the range of values taken by OP can be inferred after STMT executes,
3991 return the comparison code (COMP_CODE_P) and value (VAL_P) that
3992 describes the inferred range. Return true if a range could be
3996 infer_value_range (gimple stmt, tree op, enum tree_code *comp_code_p, tree *val_p)
3999 *comp_code_p = ERROR_MARK;
4001 /* Do not attempt to infer anything in names that flow through
4003 if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (op))
4006 /* Similarly, don't infer anything from statements that may throw
4008 if (stmt_could_throw_p (stmt))
4011 /* If STMT is the last statement of a basic block with no
4012 successors, there is no point inferring anything about any of its
4013 operands. We would not be able to find a proper insertion point
4014 for the assertion, anyway. */
4015 if (stmt_ends_bb_p (stmt) && EDGE_COUNT (gimple_bb (stmt)->succs) == 0)
4018 /* We can only assume that a pointer dereference will yield
4019 non-NULL if -fdelete-null-pointer-checks is enabled. */
4020 if (flag_delete_null_pointer_checks
4021 && POINTER_TYPE_P (TREE_TYPE (op))
4022 && gimple_code (stmt) != GIMPLE_ASM)
4024 unsigned num_uses, num_loads, num_stores;
4026 count_uses_and_derefs (op, stmt, &num_uses, &num_loads, &num_stores);
4027 if (num_loads + num_stores > 0)
4029 *val_p = build_int_cst (TREE_TYPE (op), 0);
4030 *comp_code_p = NE_EXPR;
4039 void dump_asserts_for (FILE *, tree);
4040 void debug_asserts_for (tree);
4041 void dump_all_asserts (FILE *);
4042 void debug_all_asserts (void);
4044 /* Dump all the registered assertions for NAME to FILE. */
4047 dump_asserts_for (FILE *file, tree name)
4051 fprintf (file, "Assertions to be inserted for ");
4052 print_generic_expr (file, name, 0);
4053 fprintf (file, "\n");
4055 loc = asserts_for[SSA_NAME_VERSION (name)];
4058 fprintf (file, "\t");
4059 print_gimple_stmt (file, gsi_stmt (loc->si), 0, 0);
4060 fprintf (file, "\n\tBB #%d", loc->bb->index);
4063 fprintf (file, "\n\tEDGE %d->%d", loc->e->src->index,
4064 loc->e->dest->index);
4065 dump_edge_info (file, loc->e, 0);
4067 fprintf (file, "\n\tPREDICATE: ");
4068 print_generic_expr (file, name, 0);
4069 fprintf (file, " %s ", tree_code_name[(int)loc->comp_code]);
4070 print_generic_expr (file, loc->val, 0);
4071 fprintf (file, "\n\n");
4075 fprintf (file, "\n");
4079 /* Dump all the registered assertions for NAME to stderr. */
4082 debug_asserts_for (tree name)
4084 dump_asserts_for (stderr, name);
4088 /* Dump all the registered assertions for all the names to FILE. */
4091 dump_all_asserts (FILE *file)
4096 fprintf (file, "\nASSERT_EXPRs to be inserted\n\n");
4097 EXECUTE_IF_SET_IN_BITMAP (need_assert_for, 0, i, bi)
4098 dump_asserts_for (file, ssa_name (i));
4099 fprintf (file, "\n");
4103 /* Dump all the registered assertions for all the names to stderr. */
4106 debug_all_asserts (void)
4108 dump_all_asserts (stderr);
4112 /* If NAME doesn't have an ASSERT_EXPR registered for asserting
4113 'EXPR COMP_CODE VAL' at a location that dominates block BB or
4114 E->DEST, then register this location as a possible insertion point
4115 for ASSERT_EXPR <NAME, EXPR COMP_CODE VAL>.
4117 BB, E and SI provide the exact insertion point for the new
4118 ASSERT_EXPR. If BB is NULL, then the ASSERT_EXPR is to be inserted
4119 on edge E. Otherwise, if E is NULL, the ASSERT_EXPR is inserted on
4120 BB. If SI points to a COND_EXPR or a SWITCH_EXPR statement, then E
4121 must not be NULL. */
4124 register_new_assert_for (tree name, tree expr,
4125 enum tree_code comp_code,
4129 gimple_stmt_iterator si)
4131 assert_locus_t n, loc, last_loc;
4132 basic_block dest_bb;
4134 gcc_checking_assert (bb == NULL || e == NULL);
4137 gcc_checking_assert (gimple_code (gsi_stmt (si)) != GIMPLE_COND
4138 && gimple_code (gsi_stmt (si)) != GIMPLE_SWITCH);
4140 /* Never build an assert comparing against an integer constant with
4141 TREE_OVERFLOW set. This confuses our undefined overflow warning
4143 if (TREE_CODE (val) == INTEGER_CST
4144 && TREE_OVERFLOW (val))
4145 val = build_int_cst_wide (TREE_TYPE (val),
4146 TREE_INT_CST_LOW (val), TREE_INT_CST_HIGH (val));
4148 /* The new assertion A will be inserted at BB or E. We need to
4149 determine if the new location is dominated by a previously
4150 registered location for A. If we are doing an edge insertion,
4151 assume that A will be inserted at E->DEST. Note that this is not
4154 If E is a critical edge, it will be split. But even if E is
4155 split, the new block will dominate the same set of blocks that
4158 The reverse, however, is not true, blocks dominated by E->DEST
4159 will not be dominated by the new block created to split E. So,
4160 if the insertion location is on a critical edge, we will not use
4161 the new location to move another assertion previously registered
4162 at a block dominated by E->DEST. */
4163 dest_bb = (bb) ? bb : e->dest;
4165 /* If NAME already has an ASSERT_EXPR registered for COMP_CODE and
4166 VAL at a block dominating DEST_BB, then we don't need to insert a new
4167 one. Similarly, if the same assertion already exists at a block
4168 dominated by DEST_BB and the new location is not on a critical
4169 edge, then update the existing location for the assertion (i.e.,
4170 move the assertion up in the dominance tree).
4172 Note, this is implemented as a simple linked list because there
4173 should not be more than a handful of assertions registered per
4174 name. If this becomes a performance problem, a table hashed by
4175 COMP_CODE and VAL could be implemented. */
4176 loc = asserts_for[SSA_NAME_VERSION (name)];
4180 if (loc->comp_code == comp_code
4182 || operand_equal_p (loc->val, val, 0))
4183 && (loc->expr == expr
4184 || operand_equal_p (loc->expr, expr, 0)))
4186 /* If the assertion NAME COMP_CODE VAL has already been
4187 registered at a basic block that dominates DEST_BB, then
4188 we don't need to insert the same assertion again. Note
4189 that we don't check strict dominance here to avoid
4190 replicating the same assertion inside the same basic
4191 block more than once (e.g., when a pointer is
4192 dereferenced several times inside a block).
4194 An exception to this rule are edge insertions. If the
4195 new assertion is to be inserted on edge E, then it will
4196 dominate all the other insertions that we may want to
4197 insert in DEST_BB. So, if we are doing an edge
4198 insertion, don't do this dominance check. */
4200 && dominated_by_p (CDI_DOMINATORS, dest_bb, loc->bb))
4203 /* Otherwise, if E is not a critical edge and DEST_BB
4204 dominates the existing location for the assertion, move
4205 the assertion up in the dominance tree by updating its
4206 location information. */
4207 if ((e == NULL || !EDGE_CRITICAL_P (e))
4208 && dominated_by_p (CDI_DOMINATORS, loc->bb, dest_bb))
4217 /* Update the last node of the list and move to the next one. */
4222 /* If we didn't find an assertion already registered for
4223 NAME COMP_CODE VAL, add a new one at the end of the list of
4224 assertions associated with NAME. */
4225 n = XNEW (struct assert_locus_d);
4229 n->comp_code = comp_code;
4237 asserts_for[SSA_NAME_VERSION (name)] = n;
4239 bitmap_set_bit (need_assert_for, SSA_NAME_VERSION (name));
4242 /* (COND_OP0 COND_CODE COND_OP1) is a predicate which uses NAME.
4243 Extract a suitable test code and value and store them into *CODE_P and
4244 *VAL_P so the predicate is normalized to NAME *CODE_P *VAL_P.
4246 If no extraction was possible, return FALSE, otherwise return TRUE.
4248 If INVERT is true, then we invert the result stored into *CODE_P. */
4251 extract_code_and_val_from_cond_with_ops (tree name, enum tree_code cond_code,
4252 tree cond_op0, tree cond_op1,
4253 bool invert, enum tree_code *code_p,
4256 enum tree_code comp_code;
4259 /* Otherwise, we have a comparison of the form NAME COMP VAL
4260 or VAL COMP NAME. */
4261 if (name == cond_op1)
4263 /* If the predicate is of the form VAL COMP NAME, flip
4264 COMP around because we need to register NAME as the
4265 first operand in the predicate. */
4266 comp_code = swap_tree_comparison (cond_code);
4271 /* The comparison is of the form NAME COMP VAL, so the
4272 comparison code remains unchanged. */
4273 comp_code = cond_code;
4277 /* Invert the comparison code as necessary. */
4279 comp_code = invert_tree_comparison (comp_code, 0);
4281 /* VRP does not handle float types. */
4282 if (SCALAR_FLOAT_TYPE_P (TREE_TYPE (val)))
4285 /* Do not register always-false predicates.
4286 FIXME: this works around a limitation in fold() when dealing with
4287 enumerations. Given 'enum { N1, N2 } x;', fold will not
4288 fold 'if (x > N2)' to 'if (0)'. */
4289 if ((comp_code == GT_EXPR || comp_code == LT_EXPR)
4290 && INTEGRAL_TYPE_P (TREE_TYPE (val)))
4292 tree min = TYPE_MIN_VALUE (TREE_TYPE (val));
4293 tree max = TYPE_MAX_VALUE (TREE_TYPE (val));
4295 if (comp_code == GT_EXPR
4297 || compare_values (val, max) == 0))
4300 if (comp_code == LT_EXPR
4302 || compare_values (val, min) == 0))
4305 *code_p = comp_code;
4310 /* Try to register an edge assertion for SSA name NAME on edge E for
4311 the condition COND contributing to the conditional jump pointed to by BSI.
4312 Invert the condition COND if INVERT is true.
4313 Return true if an assertion for NAME could be registered. */
4316 register_edge_assert_for_2 (tree name, edge e, gimple_stmt_iterator bsi,
4317 enum tree_code cond_code,
4318 tree cond_op0, tree cond_op1, bool invert)
4321 enum tree_code comp_code;
4322 bool retval = false;
4324 if (!extract_code_and_val_from_cond_with_ops (name, cond_code,
4327 invert, &comp_code, &val))
4330 /* Only register an ASSERT_EXPR if NAME was found in the sub-graph
4331 reachable from E. */
4332 if (live_on_edge (e, name)
4333 && !has_single_use (name))
4335 register_new_assert_for (name, name, comp_code, val, NULL, e, bsi);
4339 /* In the case of NAME <= CST and NAME being defined as
4340 NAME = (unsigned) NAME2 + CST2 we can assert NAME2 >= -CST2
4341 and NAME2 <= CST - CST2. We can do the same for NAME > CST.
4342 This catches range and anti-range tests. */
4343 if ((comp_code == LE_EXPR
4344 || comp_code == GT_EXPR)
4345 && TREE_CODE (val) == INTEGER_CST
4346 && TYPE_UNSIGNED (TREE_TYPE (val)))
4348 gimple def_stmt = SSA_NAME_DEF_STMT (name);
4349 tree cst2 = NULL_TREE, name2 = NULL_TREE, name3 = NULL_TREE;
4351 /* Extract CST2 from the (optional) addition. */
4352 if (is_gimple_assign (def_stmt)
4353 && gimple_assign_rhs_code (def_stmt) == PLUS_EXPR)
4355 name2 = gimple_assign_rhs1 (def_stmt);
4356 cst2 = gimple_assign_rhs2 (def_stmt);
4357 if (TREE_CODE (name2) == SSA_NAME
4358 && TREE_CODE (cst2) == INTEGER_CST)
4359 def_stmt = SSA_NAME_DEF_STMT (name2);
4362 /* Extract NAME2 from the (optional) sign-changing cast. */
4363 if (gimple_assign_cast_p (def_stmt))
4365 if (CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (def_stmt))
4366 && ! TYPE_UNSIGNED (TREE_TYPE (gimple_assign_rhs1 (def_stmt)))
4367 && (TYPE_PRECISION (gimple_expr_type (def_stmt))
4368 == TYPE_PRECISION (TREE_TYPE (gimple_assign_rhs1 (def_stmt)))))
4369 name3 = gimple_assign_rhs1 (def_stmt);
4372 /* If name3 is used later, create an ASSERT_EXPR for it. */
4373 if (name3 != NULL_TREE
4374 && TREE_CODE (name3) == SSA_NAME
4375 && (cst2 == NULL_TREE
4376 || TREE_CODE (cst2) == INTEGER_CST)
4377 && INTEGRAL_TYPE_P (TREE_TYPE (name3))
4378 && live_on_edge (e, name3)
4379 && !has_single_use (name3))
4383 /* Build an expression for the range test. */
4384 tmp = build1 (NOP_EXPR, TREE_TYPE (name), name3);
4385 if (cst2 != NULL_TREE)
4386 tmp = build2 (PLUS_EXPR, TREE_TYPE (name), tmp, cst2);
4390 fprintf (dump_file, "Adding assert for ");
4391 print_generic_expr (dump_file, name3, 0);
4392 fprintf (dump_file, " from ");
4393 print_generic_expr (dump_file, tmp, 0);
4394 fprintf (dump_file, "\n");
4397 register_new_assert_for (name3, tmp, comp_code, val, NULL, e, bsi);
4402 /* If name2 is used later, create an ASSERT_EXPR for it. */
4403 if (name2 != NULL_TREE
4404 && TREE_CODE (name2) == SSA_NAME
4405 && TREE_CODE (cst2) == INTEGER_CST
4406 && INTEGRAL_TYPE_P (TREE_TYPE (name2))
4407 && live_on_edge (e, name2)
4408 && !has_single_use (name2))
4412 /* Build an expression for the range test. */
4414 if (TREE_TYPE (name) != TREE_TYPE (name2))
4415 tmp = build1 (NOP_EXPR, TREE_TYPE (name), tmp);
4416 if (cst2 != NULL_TREE)
4417 tmp = build2 (PLUS_EXPR, TREE_TYPE (name), tmp, cst2);
4421 fprintf (dump_file, "Adding assert for ");
4422 print_generic_expr (dump_file, name2, 0);
4423 fprintf (dump_file, " from ");
4424 print_generic_expr (dump_file, tmp, 0);
4425 fprintf (dump_file, "\n");
4428 register_new_assert_for (name2, tmp, comp_code, val, NULL, e, bsi);
4437 /* OP is an operand of a truth value expression which is known to have
4438 a particular value. Register any asserts for OP and for any
4439 operands in OP's defining statement.
4441 If CODE is EQ_EXPR, then we want to register OP is zero (false),
4442 if CODE is NE_EXPR, then we want to register OP is nonzero (true). */
4445 register_edge_assert_for_1 (tree op, enum tree_code code,
4446 edge e, gimple_stmt_iterator bsi)
4448 bool retval = false;
4451 enum tree_code rhs_code;
4453 /* We only care about SSA_NAMEs. */
4454 if (TREE_CODE (op) != SSA_NAME)
4457 /* We know that OP will have a zero or nonzero value. If OP is used
4458 more than once go ahead and register an assert for OP.
4460 The FOUND_IN_SUBGRAPH support is not helpful in this situation as
4461 it will always be set for OP (because OP is used in a COND_EXPR in
4463 if (!has_single_use (op))
4465 val = build_int_cst (TREE_TYPE (op), 0);
4466 register_new_assert_for (op, op, code, val, NULL, e, bsi);
4470 /* Now look at how OP is set. If it's set from a comparison,
4471 a truth operation or some bit operations, then we may be able
4472 to register information about the operands of that assignment. */
4473 op_def = SSA_NAME_DEF_STMT (op);
4474 if (gimple_code (op_def) != GIMPLE_ASSIGN)
4477 rhs_code = gimple_assign_rhs_code (op_def);
4479 if (TREE_CODE_CLASS (rhs_code) == tcc_comparison)
4481 bool invert = (code == EQ_EXPR ? true : false);
4482 tree op0 = gimple_assign_rhs1 (op_def);
4483 tree op1 = gimple_assign_rhs2 (op_def);
4485 if (TREE_CODE (op0) == SSA_NAME)
4486 retval |= register_edge_assert_for_2 (op0, e, bsi, rhs_code, op0, op1,
4488 if (TREE_CODE (op1) == SSA_NAME)
4489 retval |= register_edge_assert_for_2 (op1, e, bsi, rhs_code, op0, op1,
4492 else if ((code == NE_EXPR
4493 && gimple_assign_rhs_code (op_def) == BIT_AND_EXPR)
4495 && gimple_assign_rhs_code (op_def) == BIT_IOR_EXPR))
4497 /* Recurse on each operand. */
4498 retval |= register_edge_assert_for_1 (gimple_assign_rhs1 (op_def),
4500 retval |= register_edge_assert_for_1 (gimple_assign_rhs2 (op_def),
4503 else if (gimple_assign_rhs_code (op_def) == BIT_NOT_EXPR
4504 && TYPE_PRECISION (TREE_TYPE (gimple_assign_lhs (op_def))) == 1)
4506 /* Recurse, flipping CODE. */
4507 code = invert_tree_comparison (code, false);
4508 retval |= register_edge_assert_for_1 (gimple_assign_rhs1 (op_def),
4511 else if (gimple_assign_rhs_code (op_def) == SSA_NAME)
4513 /* Recurse through the copy. */
4514 retval |= register_edge_assert_for_1 (gimple_assign_rhs1 (op_def),
4517 else if (CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (op_def)))
4519 /* Recurse through the type conversion. */
4520 retval |= register_edge_assert_for_1 (gimple_assign_rhs1 (op_def),
4527 /* Try to register an edge assertion for SSA name NAME on edge E for
4528 the condition COND contributing to the conditional jump pointed to by SI.
4529 Return true if an assertion for NAME could be registered. */
4532 register_edge_assert_for (tree name, edge e, gimple_stmt_iterator si,
4533 enum tree_code cond_code, tree cond_op0,
4537 enum tree_code comp_code;
4538 bool retval = false;
4539 bool is_else_edge = (e->flags & EDGE_FALSE_VALUE) != 0;
4541 /* Do not attempt to infer anything in names that flow through
4543 if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (name))
4546 if (!extract_code_and_val_from_cond_with_ops (name, cond_code,
4552 /* Register ASSERT_EXPRs for name. */
4553 retval |= register_edge_assert_for_2 (name, e, si, cond_code, cond_op0,
4554 cond_op1, is_else_edge);
4557 /* If COND is effectively an equality test of an SSA_NAME against
4558 the value zero or one, then we may be able to assert values
4559 for SSA_NAMEs which flow into COND. */
4561 /* In the case of NAME == 1 or NAME != 0, for BIT_AND_EXPR defining
4562 statement of NAME we can assert both operands of the BIT_AND_EXPR
4563 have nonzero value. */
4564 if (((comp_code == EQ_EXPR && integer_onep (val))
4565 || (comp_code == NE_EXPR && integer_zerop (val))))
4567 gimple def_stmt = SSA_NAME_DEF_STMT (name);
4569 if (is_gimple_assign (def_stmt)
4570 && gimple_assign_rhs_code (def_stmt) == BIT_AND_EXPR)
4572 tree op0 = gimple_assign_rhs1 (def_stmt);
4573 tree op1 = gimple_assign_rhs2 (def_stmt);
4574 retval |= register_edge_assert_for_1 (op0, NE_EXPR, e, si);
4575 retval |= register_edge_assert_for_1 (op1, NE_EXPR, e, si);
4579 /* In the case of NAME == 0 or NAME != 1, for BIT_IOR_EXPR defining
4580 statement of NAME we can assert both operands of the BIT_IOR_EXPR
4582 if (((comp_code == EQ_EXPR && integer_zerop (val))
4583 || (comp_code == NE_EXPR && integer_onep (val))))
4585 gimple def_stmt = SSA_NAME_DEF_STMT (name);
4587 /* For BIT_IOR_EXPR only if NAME == 0 both operands have
4588 necessarily zero value, or if type-precision is one. */
4589 if (is_gimple_assign (def_stmt)
4590 && (gimple_assign_rhs_code (def_stmt) == BIT_IOR_EXPR
4591 && (TYPE_PRECISION (TREE_TYPE (name)) == 1
4592 || comp_code == EQ_EXPR)))
4594 tree op0 = gimple_assign_rhs1 (def_stmt);
4595 tree op1 = gimple_assign_rhs2 (def_stmt);
4596 retval |= register_edge_assert_for_1 (op0, EQ_EXPR, e, si);
4597 retval |= register_edge_assert_for_1 (op1, EQ_EXPR, e, si);
4605 /* Determine whether the outgoing edges of BB should receive an
4606 ASSERT_EXPR for each of the operands of BB's LAST statement.
4607 The last statement of BB must be a COND_EXPR.
4609 If any of the sub-graphs rooted at BB have an interesting use of
4610 the predicate operands, an assert location node is added to the
4611 list of assertions for the corresponding operands. */
4614 find_conditional_asserts (basic_block bb, gimple last)
4617 gimple_stmt_iterator bsi;
4623 need_assert = false;
4624 bsi = gsi_for_stmt (last);
4626 /* Look for uses of the operands in each of the sub-graphs
4627 rooted at BB. We need to check each of the outgoing edges
4628 separately, so that we know what kind of ASSERT_EXPR to
4630 FOR_EACH_EDGE (e, ei, bb->succs)
4635 /* Register the necessary assertions for each operand in the
4636 conditional predicate. */
4637 FOR_EACH_SSA_TREE_OPERAND (op, last, iter, SSA_OP_USE)
4639 need_assert |= register_edge_assert_for (op, e, bsi,
4640 gimple_cond_code (last),
4641 gimple_cond_lhs (last),
4642 gimple_cond_rhs (last));
4655 /* Compare two case labels sorting first by the destination bb index
4656 and then by the case value. */
4659 compare_case_labels (const void *p1, const void *p2)
4661 const struct case_info *ci1 = (const struct case_info *) p1;
4662 const struct case_info *ci2 = (const struct case_info *) p2;
4663 int idx1 = ci1->bb->index;
4664 int idx2 = ci2->bb->index;
4668 else if (idx1 == idx2)
4670 /* Make sure the default label is first in a group. */
4671 if (!CASE_LOW (ci1->expr))
4673 else if (!CASE_LOW (ci2->expr))
4676 return tree_int_cst_compare (CASE_LOW (ci1->expr),
4677 CASE_LOW (ci2->expr));
4683 /* Determine whether the outgoing edges of BB should receive an
4684 ASSERT_EXPR for each of the operands of BB's LAST statement.
4685 The last statement of BB must be a SWITCH_EXPR.
4687 If any of the sub-graphs rooted at BB have an interesting use of
4688 the predicate operands, an assert location node is added to the
4689 list of assertions for the corresponding operands. */
4692 find_switch_asserts (basic_block bb, gimple last)
4695 gimple_stmt_iterator bsi;
4698 struct case_info *ci;
4699 size_t n = gimple_switch_num_labels (last);
4700 #if GCC_VERSION >= 4000
4703 /* Work around GCC 3.4 bug (PR 37086). */
4704 volatile unsigned int idx;
4707 need_assert = false;
4708 bsi = gsi_for_stmt (last);
4709 op = gimple_switch_index (last);
4710 if (TREE_CODE (op) != SSA_NAME)
4713 /* Build a vector of case labels sorted by destination label. */
4714 ci = XNEWVEC (struct case_info, n);
4715 for (idx = 0; idx < n; ++idx)
4717 ci[idx].expr = gimple_switch_label (last, idx);
4718 ci[idx].bb = label_to_block (CASE_LABEL (ci[idx].expr));
4720 qsort (ci, n, sizeof (struct case_info), compare_case_labels);
4722 for (idx = 0; idx < n; ++idx)
4725 tree cl = ci[idx].expr;
4726 basic_block cbb = ci[idx].bb;
4728 min = CASE_LOW (cl);
4729 max = CASE_HIGH (cl);
4731 /* If there are multiple case labels with the same destination
4732 we need to combine them to a single value range for the edge. */
4733 if (idx + 1 < n && cbb == ci[idx + 1].bb)
4735 /* Skip labels until the last of the group. */
4738 } while (idx < n && cbb == ci[idx].bb);
4741 /* Pick up the maximum of the case label range. */
4742 if (CASE_HIGH (ci[idx].expr))
4743 max = CASE_HIGH (ci[idx].expr);
4745 max = CASE_LOW (ci[idx].expr);
4748 /* Nothing to do if the range includes the default label until we
4749 can register anti-ranges. */
4750 if (min == NULL_TREE)
4753 /* Find the edge to register the assert expr on. */
4754 e = find_edge (bb, cbb);
4756 /* Register the necessary assertions for the operand in the
4758 need_assert |= register_edge_assert_for (op, e, bsi,
4759 max ? GE_EXPR : EQ_EXPR,
4761 fold_convert (TREE_TYPE (op),
4765 need_assert |= register_edge_assert_for (op, e, bsi, LE_EXPR,
4767 fold_convert (TREE_TYPE (op),
4777 /* Traverse all the statements in block BB looking for statements that
4778 may generate useful assertions for the SSA names in their operand.
4779 If a statement produces a useful assertion A for name N_i, then the
4780 list of assertions already generated for N_i is scanned to
4781 determine if A is actually needed.
4783 If N_i already had the assertion A at a location dominating the
4784 current location, then nothing needs to be done. Otherwise, the
4785 new location for A is recorded instead.
4787 1- For every statement S in BB, all the variables used by S are
4788 added to bitmap FOUND_IN_SUBGRAPH.
4790 2- If statement S uses an operand N in a way that exposes a known
4791 value range for N, then if N was not already generated by an
4792 ASSERT_EXPR, create a new assert location for N. For instance,
4793 if N is a pointer and the statement dereferences it, we can
4794 assume that N is not NULL.
4796 3- COND_EXPRs are a special case of #2. We can derive range
4797 information from the predicate but need to insert different
4798 ASSERT_EXPRs for each of the sub-graphs rooted at the
4799 conditional block. If the last statement of BB is a conditional
4800 expression of the form 'X op Y', then
4802 a) Remove X and Y from the set FOUND_IN_SUBGRAPH.
4804 b) If the conditional is the only entry point to the sub-graph
4805 corresponding to the THEN_CLAUSE, recurse into it. On
4806 return, if X and/or Y are marked in FOUND_IN_SUBGRAPH, then
4807 an ASSERT_EXPR is added for the corresponding variable.
4809 c) Repeat step (b) on the ELSE_CLAUSE.
4811 d) Mark X and Y in FOUND_IN_SUBGRAPH.
4820 In this case, an assertion on the THEN clause is useful to
4821 determine that 'a' is always 9 on that edge. However, an assertion
4822 on the ELSE clause would be unnecessary.
4824 4- If BB does not end in a conditional expression, then we recurse
4825 into BB's dominator children.
4827 At the end of the recursive traversal, every SSA name will have a
4828 list of locations where ASSERT_EXPRs should be added. When a new
4829 location for name N is found, it is registered by calling
4830 register_new_assert_for. That function keeps track of all the
4831 registered assertions to prevent adding unnecessary assertions.
4832 For instance, if a pointer P_4 is dereferenced more than once in a
4833 dominator tree, only the location dominating all the dereference of
4834 P_4 will receive an ASSERT_EXPR.
4836 If this function returns true, then it means that there are names
4837 for which we need to generate ASSERT_EXPRs. Those assertions are
4838 inserted by process_assert_insertions. */
4841 find_assert_locations_1 (basic_block bb, sbitmap live)
4843 gimple_stmt_iterator si;
4848 need_assert = false;
4849 last = last_stmt (bb);
4851 /* If BB's last statement is a conditional statement involving integer
4852 operands, determine if we need to add ASSERT_EXPRs. */
4854 && gimple_code (last) == GIMPLE_COND
4855 && !fp_predicate (last)
4856 && !ZERO_SSA_OPERANDS (last, SSA_OP_USE))
4857 need_assert |= find_conditional_asserts (bb, last);
4859 /* If BB's last statement is a switch statement involving integer
4860 operands, determine if we need to add ASSERT_EXPRs. */
4862 && gimple_code (last) == GIMPLE_SWITCH
4863 && !ZERO_SSA_OPERANDS (last, SSA_OP_USE))
4864 need_assert |= find_switch_asserts (bb, last);
4866 /* Traverse all the statements in BB marking used names and looking
4867 for statements that may infer assertions for their used operands. */
4868 for (si = gsi_start_bb (bb); !gsi_end_p (si); gsi_next (&si))
4874 stmt = gsi_stmt (si);
4876 if (is_gimple_debug (stmt))
4879 /* See if we can derive an assertion for any of STMT's operands. */
4880 FOR_EACH_SSA_TREE_OPERAND (op, stmt, i, SSA_OP_USE)
4883 enum tree_code comp_code;
4885 /* Mark OP in our live bitmap. */
4886 SET_BIT (live, SSA_NAME_VERSION (op));
4888 /* If OP is used in such a way that we can infer a value
4889 range for it, and we don't find a previous assertion for
4890 it, create a new assertion location node for OP. */
4891 if (infer_value_range (stmt, op, &comp_code, &value))
4893 /* If we are able to infer a nonzero value range for OP,
4894 then walk backwards through the use-def chain to see if OP
4895 was set via a typecast.
4897 If so, then we can also infer a nonzero value range
4898 for the operand of the NOP_EXPR. */
4899 if (comp_code == NE_EXPR && integer_zerop (value))
4902 gimple def_stmt = SSA_NAME_DEF_STMT (t);
4904 while (is_gimple_assign (def_stmt)
4905 && gimple_assign_rhs_code (def_stmt) == NOP_EXPR
4907 (gimple_assign_rhs1 (def_stmt)) == SSA_NAME
4909 (TREE_TYPE (gimple_assign_rhs1 (def_stmt))))
4911 t = gimple_assign_rhs1 (def_stmt);
4912 def_stmt = SSA_NAME_DEF_STMT (t);
4914 /* Note we want to register the assert for the
4915 operand of the NOP_EXPR after SI, not after the
4917 if (! has_single_use (t))
4919 register_new_assert_for (t, t, comp_code, value,
4926 /* If OP is used only once, namely in this STMT, don't
4927 bother creating an ASSERT_EXPR for it. Such an
4928 ASSERT_EXPR would do nothing but increase compile time. */
4929 if (!has_single_use (op))
4931 register_new_assert_for (op, op, comp_code, value,
4939 /* Traverse all PHI nodes in BB marking used operands. */
4940 for (si = gsi_start_phis (bb); !gsi_end_p(si); gsi_next (&si))
4942 use_operand_p arg_p;
4944 phi = gsi_stmt (si);
4946 FOR_EACH_PHI_ARG (arg_p, phi, i, SSA_OP_USE)
4948 tree arg = USE_FROM_PTR (arg_p);
4949 if (TREE_CODE (arg) == SSA_NAME)
4950 SET_BIT (live, SSA_NAME_VERSION (arg));
4957 /* Do an RPO walk over the function computing SSA name liveness
4958 on-the-fly and deciding on assert expressions to insert.
4959 Returns true if there are assert expressions to be inserted. */
4962 find_assert_locations (void)
4964 int *rpo = XCNEWVEC (int, last_basic_block + NUM_FIXED_BLOCKS);
4965 int *bb_rpo = XCNEWVEC (int, last_basic_block + NUM_FIXED_BLOCKS);
4966 int *last_rpo = XCNEWVEC (int, last_basic_block + NUM_FIXED_BLOCKS);
4970 live = XCNEWVEC (sbitmap, last_basic_block + NUM_FIXED_BLOCKS);
4971 rpo_cnt = pre_and_rev_post_order_compute (NULL, rpo, false);
4972 for (i = 0; i < rpo_cnt; ++i)
4975 need_asserts = false;
4976 for (i = rpo_cnt-1; i >= 0; --i)
4978 basic_block bb = BASIC_BLOCK (rpo[i]);
4984 live[rpo[i]] = sbitmap_alloc (num_ssa_names);
4985 sbitmap_zero (live[rpo[i]]);
4988 /* Process BB and update the live information with uses in
4990 need_asserts |= find_assert_locations_1 (bb, live[rpo[i]]);
4992 /* Merge liveness into the predecessor blocks and free it. */
4993 if (!sbitmap_empty_p (live[rpo[i]]))
4996 FOR_EACH_EDGE (e, ei, bb->preds)
4998 int pred = e->src->index;
4999 if (e->flags & EDGE_DFS_BACK)
5004 live[pred] = sbitmap_alloc (num_ssa_names);
5005 sbitmap_zero (live[pred]);
5007 sbitmap_a_or_b (live[pred], live[pred], live[rpo[i]]);
5009 if (bb_rpo[pred] < pred_rpo)
5010 pred_rpo = bb_rpo[pred];
5013 /* Record the RPO number of the last visited block that needs
5014 live information from this block. */
5015 last_rpo[rpo[i]] = pred_rpo;
5019 sbitmap_free (live[rpo[i]]);
5020 live[rpo[i]] = NULL;
5023 /* We can free all successors live bitmaps if all their
5024 predecessors have been visited already. */
5025 FOR_EACH_EDGE (e, ei, bb->succs)
5026 if (last_rpo[e->dest->index] == i
5027 && live[e->dest->index])
5029 sbitmap_free (live[e->dest->index]);
5030 live[e->dest->index] = NULL;
5035 XDELETEVEC (bb_rpo);
5036 XDELETEVEC (last_rpo);
5037 for (i = 0; i < last_basic_block + NUM_FIXED_BLOCKS; ++i)
5039 sbitmap_free (live[i]);
5042 return need_asserts;
5045 /* Create an ASSERT_EXPR for NAME and insert it in the location
5046 indicated by LOC. Return true if we made any edge insertions. */
5049 process_assert_insertions_for (tree name, assert_locus_t loc)
5051 /* Build the comparison expression NAME_i COMP_CODE VAL. */
5058 /* If we have X <=> X do not insert an assert expr for that. */
5059 if (loc->expr == loc->val)
5062 cond = build2 (loc->comp_code, boolean_type_node, loc->expr, loc->val);
5063 assert_stmt = build_assert_expr_for (cond, name);
5066 /* We have been asked to insert the assertion on an edge. This
5067 is used only by COND_EXPR and SWITCH_EXPR assertions. */
5068 gcc_checking_assert (gimple_code (gsi_stmt (loc->si)) == GIMPLE_COND
5069 || (gimple_code (gsi_stmt (loc->si))
5072 gsi_insert_on_edge (loc->e, assert_stmt);
5076 /* Otherwise, we can insert right after LOC->SI iff the
5077 statement must not be the last statement in the block. */
5078 stmt = gsi_stmt (loc->si);
5079 if (!stmt_ends_bb_p (stmt))
5081 gsi_insert_after (&loc->si, assert_stmt, GSI_SAME_STMT);
5085 /* If STMT must be the last statement in BB, we can only insert new
5086 assertions on the non-abnormal edge out of BB. Note that since
5087 STMT is not control flow, there may only be one non-abnormal edge
5089 FOR_EACH_EDGE (e, ei, loc->bb->succs)
5090 if (!(e->flags & EDGE_ABNORMAL))
5092 gsi_insert_on_edge (e, assert_stmt);
5100 /* Process all the insertions registered for every name N_i registered
5101 in NEED_ASSERT_FOR. The list of assertions to be inserted are
5102 found in ASSERTS_FOR[i]. */
5105 process_assert_insertions (void)
5109 bool update_edges_p = false;
5110 int num_asserts = 0;
5112 if (dump_file && (dump_flags & TDF_DETAILS))
5113 dump_all_asserts (dump_file);
5115 EXECUTE_IF_SET_IN_BITMAP (need_assert_for, 0, i, bi)
5117 assert_locus_t loc = asserts_for[i];
5122 assert_locus_t next = loc->next;
5123 update_edges_p |= process_assert_insertions_for (ssa_name (i), loc);
5131 gsi_commit_edge_inserts ();
5133 statistics_counter_event (cfun, "Number of ASSERT_EXPR expressions inserted",
5138 /* Traverse the flowgraph looking for conditional jumps to insert range
5139 expressions. These range expressions are meant to provide information
5140 to optimizations that need to reason in terms of value ranges. They
5141 will not be expanded into RTL. For instance, given:
5150 this pass will transform the code into:
5156 x = ASSERT_EXPR <x, x < y>
5161 y = ASSERT_EXPR <y, x <= y>
5165 The idea is that once copy and constant propagation have run, other
5166 optimizations will be able to determine what ranges of values can 'x'
5167 take in different paths of the code, simply by checking the reaching
5168 definition of 'x'. */
5171 insert_range_assertions (void)
5173 need_assert_for = BITMAP_ALLOC (NULL);
5174 asserts_for = XCNEWVEC (assert_locus_t, num_ssa_names);
5176 calculate_dominance_info (CDI_DOMINATORS);
5178 if (find_assert_locations ())
5180 process_assert_insertions ();
5181 update_ssa (TODO_update_ssa_no_phi);
5184 if (dump_file && (dump_flags & TDF_DETAILS))
5186 fprintf (dump_file, "\nSSA form after inserting ASSERT_EXPRs\n");
5187 dump_function_to_file (current_function_decl, dump_file, dump_flags);
5191 BITMAP_FREE (need_assert_for);
5194 /* Checks one ARRAY_REF in REF, located at LOCUS. Ignores flexible arrays
5195 and "struct" hacks. If VRP can determine that the
5196 array subscript is a constant, check if it is outside valid
5197 range. If the array subscript is a RANGE, warn if it is
5198 non-overlapping with valid range.
5199 IGNORE_OFF_BY_ONE is true if the ARRAY_REF is inside a ADDR_EXPR. */
5202 check_array_ref (location_t location, tree ref, bool ignore_off_by_one)
5204 value_range_t* vr = NULL;
5205 tree low_sub, up_sub;
5206 tree low_bound, up_bound, up_bound_p1;
5209 if (TREE_NO_WARNING (ref))
5212 low_sub = up_sub = TREE_OPERAND (ref, 1);
5213 up_bound = array_ref_up_bound (ref);
5215 /* Can not check flexible arrays. */
5217 || TREE_CODE (up_bound) != INTEGER_CST)
5220 /* Accesses to trailing arrays via pointers may access storage
5221 beyond the types array bounds. */
5222 base = get_base_address (ref);
5223 if (base && TREE_CODE (base) == MEM_REF)
5225 tree cref, next = NULL_TREE;
5227 if (TREE_CODE (TREE_OPERAND (ref, 0)) != COMPONENT_REF)
5230 cref = TREE_OPERAND (ref, 0);
5231 if (TREE_CODE (TREE_TYPE (TREE_OPERAND (cref, 0))) == RECORD_TYPE)
5232 for (next = DECL_CHAIN (TREE_OPERAND (cref, 1));
5233 next && TREE_CODE (next) != FIELD_DECL;
5234 next = DECL_CHAIN (next))
5237 /* If this is the last field in a struct type or a field in a
5238 union type do not warn. */
5243 low_bound = array_ref_low_bound (ref);
5244 up_bound_p1 = int_const_binop (PLUS_EXPR, up_bound, integer_one_node);
5246 if (TREE_CODE (low_sub) == SSA_NAME)
5248 vr = get_value_range (low_sub);
5249 if (vr->type == VR_RANGE || vr->type == VR_ANTI_RANGE)
5251 low_sub = vr->type == VR_RANGE ? vr->max : vr->min;
5252 up_sub = vr->type == VR_RANGE ? vr->min : vr->max;
5256 if (vr && vr->type == VR_ANTI_RANGE)
5258 if (TREE_CODE (up_sub) == INTEGER_CST
5259 && tree_int_cst_lt (up_bound, up_sub)
5260 && TREE_CODE (low_sub) == INTEGER_CST
5261 && tree_int_cst_lt (low_sub, low_bound))
5263 warning_at (location, OPT_Warray_bounds,
5264 "array subscript is outside array bounds");
5265 TREE_NO_WARNING (ref) = 1;
5268 else if (TREE_CODE (up_sub) == INTEGER_CST
5269 && (ignore_off_by_one
5270 ? (tree_int_cst_lt (up_bound, up_sub)
5271 && !tree_int_cst_equal (up_bound_p1, up_sub))
5272 : (tree_int_cst_lt (up_bound, up_sub)
5273 || tree_int_cst_equal (up_bound_p1, up_sub))))
5275 warning_at (location, OPT_Warray_bounds,
5276 "array subscript is above array bounds");
5277 TREE_NO_WARNING (ref) = 1;
5279 else if (TREE_CODE (low_sub) == INTEGER_CST
5280 && tree_int_cst_lt (low_sub, low_bound))
5282 warning_at (location, OPT_Warray_bounds,
5283 "array subscript is below array bounds");
5284 TREE_NO_WARNING (ref) = 1;
5288 /* Searches if the expr T, located at LOCATION computes
5289 address of an ARRAY_REF, and call check_array_ref on it. */
5292 search_for_addr_array (tree t, location_t location)
5294 while (TREE_CODE (t) == SSA_NAME)
5296 gimple g = SSA_NAME_DEF_STMT (t);
5298 if (gimple_code (g) != GIMPLE_ASSIGN)
5301 if (get_gimple_rhs_class (gimple_assign_rhs_code (g))
5302 != GIMPLE_SINGLE_RHS)
5305 t = gimple_assign_rhs1 (g);
5309 /* We are only interested in addresses of ARRAY_REF's. */
5310 if (TREE_CODE (t) != ADDR_EXPR)
5313 /* Check each ARRAY_REFs in the reference chain. */
5316 if (TREE_CODE (t) == ARRAY_REF)
5317 check_array_ref (location, t, true /*ignore_off_by_one*/);
5319 t = TREE_OPERAND (t, 0);
5321 while (handled_component_p (t));
5323 if (TREE_CODE (t) == MEM_REF
5324 && TREE_CODE (TREE_OPERAND (t, 0)) == ADDR_EXPR
5325 && !TREE_NO_WARNING (t))
5327 tree tem = TREE_OPERAND (TREE_OPERAND (t, 0), 0);
5328 tree low_bound, up_bound, el_sz;
5330 if (TREE_CODE (TREE_TYPE (tem)) != ARRAY_TYPE
5331 || TREE_CODE (TREE_TYPE (TREE_TYPE (tem))) == ARRAY_TYPE
5332 || !TYPE_DOMAIN (TREE_TYPE (tem)))
5335 low_bound = TYPE_MIN_VALUE (TYPE_DOMAIN (TREE_TYPE (tem)));
5336 up_bound = TYPE_MAX_VALUE (TYPE_DOMAIN (TREE_TYPE (tem)));
5337 el_sz = TYPE_SIZE_UNIT (TREE_TYPE (TREE_TYPE (tem)));
5339 || TREE_CODE (low_bound) != INTEGER_CST
5341 || TREE_CODE (up_bound) != INTEGER_CST
5343 || TREE_CODE (el_sz) != INTEGER_CST)
5346 idx = mem_ref_offset (t);
5347 idx = double_int_sdiv (idx, tree_to_double_int (el_sz), TRUNC_DIV_EXPR);
5348 if (double_int_scmp (idx, double_int_zero) < 0)
5350 warning_at (location, OPT_Warray_bounds,
5351 "array subscript is below array bounds");
5352 TREE_NO_WARNING (t) = 1;
5354 else if (double_int_scmp (idx,
5357 (tree_to_double_int (up_bound),
5359 (tree_to_double_int (low_bound))),
5360 double_int_one)) > 0)
5362 warning_at (location, OPT_Warray_bounds,
5363 "array subscript is above array bounds");
5364 TREE_NO_WARNING (t) = 1;
5369 /* walk_tree() callback that checks if *TP is
5370 an ARRAY_REF inside an ADDR_EXPR (in which an array
5371 subscript one outside the valid range is allowed). Call
5372 check_array_ref for each ARRAY_REF found. The location is
5376 check_array_bounds (tree *tp, int *walk_subtree, void *data)
5379 struct walk_stmt_info *wi = (struct walk_stmt_info *) data;
5380 location_t location;
5382 if (EXPR_HAS_LOCATION (t))
5383 location = EXPR_LOCATION (t);
5386 location_t *locp = (location_t *) wi->info;
5390 *walk_subtree = TRUE;
5392 if (TREE_CODE (t) == ARRAY_REF)
5393 check_array_ref (location, t, false /*ignore_off_by_one*/);
5395 if (TREE_CODE (t) == MEM_REF
5396 || (TREE_CODE (t) == RETURN_EXPR && TREE_OPERAND (t, 0)))
5397 search_for_addr_array (TREE_OPERAND (t, 0), location);
5399 if (TREE_CODE (t) == ADDR_EXPR)
5400 *walk_subtree = FALSE;
5405 /* Walk over all statements of all reachable BBs and call check_array_bounds
5409 check_all_array_refs (void)
5412 gimple_stmt_iterator si;
5418 bool executable = false;
5420 /* Skip blocks that were found to be unreachable. */
5421 FOR_EACH_EDGE (e, ei, bb->preds)
5422 executable |= !!(e->flags & EDGE_EXECUTABLE);
5426 for (si = gsi_start_bb (bb); !gsi_end_p (si); gsi_next (&si))
5428 gimple stmt = gsi_stmt (si);
5429 struct walk_stmt_info wi;
5430 if (!gimple_has_location (stmt))
5433 if (is_gimple_call (stmt))
5436 size_t n = gimple_call_num_args (stmt);
5437 for (i = 0; i < n; i++)
5439 tree arg = gimple_call_arg (stmt, i);
5440 search_for_addr_array (arg, gimple_location (stmt));
5445 memset (&wi, 0, sizeof (wi));
5446 wi.info = CONST_CAST (void *, (const void *)
5447 gimple_location_ptr (stmt));
5449 walk_gimple_op (gsi_stmt (si),
5457 /* Convert range assertion expressions into the implied copies and
5458 copy propagate away the copies. Doing the trivial copy propagation
5459 here avoids the need to run the full copy propagation pass after
5462 FIXME, this will eventually lead to copy propagation removing the
5463 names that had useful range information attached to them. For
5464 instance, if we had the assertion N_i = ASSERT_EXPR <N_j, N_j > 3>,
5465 then N_i will have the range [3, +INF].
5467 However, by converting the assertion into the implied copy
5468 operation N_i = N_j, we will then copy-propagate N_j into the uses
5469 of N_i and lose the range information. We may want to hold on to
5470 ASSERT_EXPRs a little while longer as the ranges could be used in
5471 things like jump threading.
5473 The problem with keeping ASSERT_EXPRs around is that passes after
5474 VRP need to handle them appropriately.
5476 Another approach would be to make the range information a first
5477 class property of the SSA_NAME so that it can be queried from
5478 any pass. This is made somewhat more complex by the need for
5479 multiple ranges to be associated with one SSA_NAME. */
5482 remove_range_assertions (void)
5485 gimple_stmt_iterator si;
5487 /* Note that the BSI iterator bump happens at the bottom of the
5488 loop and no bump is necessary if we're removing the statement
5489 referenced by the current BSI. */
5491 for (si = gsi_start_bb (bb); !gsi_end_p (si);)
5493 gimple stmt = gsi_stmt (si);
5496 if (is_gimple_assign (stmt)
5497 && gimple_assign_rhs_code (stmt) == ASSERT_EXPR)
5499 tree rhs = gimple_assign_rhs1 (stmt);
5501 tree cond = fold (ASSERT_EXPR_COND (rhs));
5502 use_operand_p use_p;
5503 imm_use_iterator iter;
5505 gcc_assert (cond != boolean_false_node);
5507 /* Propagate the RHS into every use of the LHS. */
5508 var = ASSERT_EXPR_VAR (rhs);
5509 FOR_EACH_IMM_USE_STMT (use_stmt, iter,
5510 gimple_assign_lhs (stmt))
5511 FOR_EACH_IMM_USE_ON_STMT (use_p, iter)
5513 SET_USE (use_p, var);
5514 gcc_assert (TREE_CODE (var) == SSA_NAME);
5517 /* And finally, remove the copy, it is not needed. */
5518 gsi_remove (&si, true);
5519 release_defs (stmt);
5527 /* Return true if STMT is interesting for VRP. */
5530 stmt_interesting_for_vrp (gimple stmt)
5532 if (gimple_code (stmt) == GIMPLE_PHI
5533 && is_gimple_reg (gimple_phi_result (stmt))
5534 && (INTEGRAL_TYPE_P (TREE_TYPE (gimple_phi_result (stmt)))
5535 || POINTER_TYPE_P (TREE_TYPE (gimple_phi_result (stmt)))))
5537 else if (is_gimple_assign (stmt) || is_gimple_call (stmt))
5539 tree lhs = gimple_get_lhs (stmt);
5541 /* In general, assignments with virtual operands are not useful
5542 for deriving ranges, with the obvious exception of calls to
5543 builtin functions. */
5544 if (lhs && TREE_CODE (lhs) == SSA_NAME
5545 && (INTEGRAL_TYPE_P (TREE_TYPE (lhs))
5546 || POINTER_TYPE_P (TREE_TYPE (lhs)))
5547 && ((is_gimple_call (stmt)
5548 && gimple_call_fndecl (stmt) != NULL_TREE
5549 && DECL_IS_BUILTIN (gimple_call_fndecl (stmt)))
5550 || !gimple_vuse (stmt)))
5553 else if (gimple_code (stmt) == GIMPLE_COND
5554 || gimple_code (stmt) == GIMPLE_SWITCH)
5561 /* Initialize local data structures for VRP. */
5564 vrp_initialize (void)
5568 values_propagated = false;
5569 num_vr_values = num_ssa_names;
5570 vr_value = XCNEWVEC (value_range_t *, num_vr_values);
5571 vr_phi_edge_counts = XCNEWVEC (int, num_ssa_names);
5575 gimple_stmt_iterator si;
5577 for (si = gsi_start_phis (bb); !gsi_end_p (si); gsi_next (&si))
5579 gimple phi = gsi_stmt (si);
5580 if (!stmt_interesting_for_vrp (phi))
5582 tree lhs = PHI_RESULT (phi);
5583 set_value_range_to_varying (get_value_range (lhs));
5584 prop_set_simulate_again (phi, false);
5587 prop_set_simulate_again (phi, true);
5590 for (si = gsi_start_bb (bb); !gsi_end_p (si); gsi_next (&si))
5592 gimple stmt = gsi_stmt (si);
5594 /* If the statement is a control insn, then we do not
5595 want to avoid simulating the statement once. Failure
5596 to do so means that those edges will never get added. */
5597 if (stmt_ends_bb_p (stmt))
5598 prop_set_simulate_again (stmt, true);
5599 else if (!stmt_interesting_for_vrp (stmt))
5603 FOR_EACH_SSA_TREE_OPERAND (def, stmt, i, SSA_OP_DEF)
5604 set_value_range_to_varying (get_value_range (def));
5605 prop_set_simulate_again (stmt, false);
5608 prop_set_simulate_again (stmt, true);
5613 /* Return the singleton value-range for NAME or NAME. */
5616 vrp_valueize (tree name)
5618 if (TREE_CODE (name) == SSA_NAME)
5620 value_range_t *vr = get_value_range (name);
5621 if (vr->type == VR_RANGE
5622 && (vr->min == vr->max
5623 || operand_equal_p (vr->min, vr->max, 0)))
5629 /* Visit assignment STMT. If it produces an interesting range, record
5630 the SSA name in *OUTPUT_P. */
5632 static enum ssa_prop_result
5633 vrp_visit_assignment_or_call (gimple stmt, tree *output_p)
5637 enum gimple_code code = gimple_code (stmt);
5638 lhs = gimple_get_lhs (stmt);
5640 /* We only keep track of ranges in integral and pointer types. */
5641 if (TREE_CODE (lhs) == SSA_NAME
5642 && ((INTEGRAL_TYPE_P (TREE_TYPE (lhs))
5643 /* It is valid to have NULL MIN/MAX values on a type. See
5644 build_range_type. */
5645 && TYPE_MIN_VALUE (TREE_TYPE (lhs))
5646 && TYPE_MAX_VALUE (TREE_TYPE (lhs)))
5647 || POINTER_TYPE_P (TREE_TYPE (lhs))))
5649 value_range_t new_vr = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
5651 /* Try folding the statement to a constant first. */
5652 tree tem = gimple_fold_stmt_to_constant (stmt, vrp_valueize);
5653 if (tem && !is_overflow_infinity (tem))
5654 set_value_range (&new_vr, VR_RANGE, tem, tem, NULL);
5655 /* Then dispatch to value-range extracting functions. */
5656 else if (code == GIMPLE_CALL)
5657 extract_range_basic (&new_vr, stmt);
5659 extract_range_from_assignment (&new_vr, stmt);
5661 if (update_value_range (lhs, &new_vr))
5665 if (dump_file && (dump_flags & TDF_DETAILS))
5667 fprintf (dump_file, "Found new range for ");
5668 print_generic_expr (dump_file, lhs, 0);
5669 fprintf (dump_file, ": ");
5670 dump_value_range (dump_file, &new_vr);
5671 fprintf (dump_file, "\n\n");
5674 if (new_vr.type == VR_VARYING)
5675 return SSA_PROP_VARYING;
5677 return SSA_PROP_INTERESTING;
5680 return SSA_PROP_NOT_INTERESTING;
5683 /* Every other statement produces no useful ranges. */
5684 FOR_EACH_SSA_TREE_OPERAND (def, stmt, iter, SSA_OP_DEF)
5685 set_value_range_to_varying (get_value_range (def));
5687 return SSA_PROP_VARYING;
5690 /* Helper that gets the value range of the SSA_NAME with version I
5691 or a symbolic range containing the SSA_NAME only if the value range
5692 is varying or undefined. */
5694 static inline value_range_t
5695 get_vr_for_comparison (int i)
5697 value_range_t vr = *get_value_range (ssa_name (i));
5699 /* If name N_i does not have a valid range, use N_i as its own
5700 range. This allows us to compare against names that may
5701 have N_i in their ranges. */
5702 if (vr.type == VR_VARYING || vr.type == VR_UNDEFINED)
5705 vr.min = ssa_name (i);
5706 vr.max = ssa_name (i);
5712 /* Compare all the value ranges for names equivalent to VAR with VAL
5713 using comparison code COMP. Return the same value returned by
5714 compare_range_with_value, including the setting of
5715 *STRICT_OVERFLOW_P. */
5718 compare_name_with_value (enum tree_code comp, tree var, tree val,
5719 bool *strict_overflow_p)
5725 int used_strict_overflow;
5727 value_range_t equiv_vr;
5729 /* Get the set of equivalences for VAR. */
5730 e = get_value_range (var)->equiv;
5732 /* Start at -1. Set it to 0 if we do a comparison without relying
5733 on overflow, or 1 if all comparisons rely on overflow. */
5734 used_strict_overflow = -1;
5736 /* Compare vars' value range with val. */
5737 equiv_vr = get_vr_for_comparison (SSA_NAME_VERSION (var));
5739 retval = compare_range_with_value (comp, &equiv_vr, val, &sop);
5741 used_strict_overflow = sop ? 1 : 0;
5743 /* If the equiv set is empty we have done all work we need to do. */
5747 && used_strict_overflow > 0)
5748 *strict_overflow_p = true;
5752 EXECUTE_IF_SET_IN_BITMAP (e, 0, i, bi)
5754 equiv_vr = get_vr_for_comparison (i);
5756 t = compare_range_with_value (comp, &equiv_vr, val, &sop);
5759 /* If we get different answers from different members
5760 of the equivalence set this check must be in a dead
5761 code region. Folding it to a trap representation
5762 would be correct here. For now just return don't-know. */
5772 used_strict_overflow = 0;
5773 else if (used_strict_overflow < 0)
5774 used_strict_overflow = 1;
5779 && used_strict_overflow > 0)
5780 *strict_overflow_p = true;
5786 /* Given a comparison code COMP and names N1 and N2, compare all the
5787 ranges equivalent to N1 against all the ranges equivalent to N2
5788 to determine the value of N1 COMP N2. Return the same value
5789 returned by compare_ranges. Set *STRICT_OVERFLOW_P to indicate
5790 whether we relied on an overflow infinity in the comparison. */
5794 compare_names (enum tree_code comp, tree n1, tree n2,
5795 bool *strict_overflow_p)
5799 bitmap_iterator bi1, bi2;
5801 int used_strict_overflow;
5802 static bitmap_obstack *s_obstack = NULL;
5803 static bitmap s_e1 = NULL, s_e2 = NULL;
5805 /* Compare the ranges of every name equivalent to N1 against the
5806 ranges of every name equivalent to N2. */
5807 e1 = get_value_range (n1)->equiv;
5808 e2 = get_value_range (n2)->equiv;
5810 /* Use the fake bitmaps if e1 or e2 are not available. */
5811 if (s_obstack == NULL)
5813 s_obstack = XNEW (bitmap_obstack);
5814 bitmap_obstack_initialize (s_obstack);
5815 s_e1 = BITMAP_ALLOC (s_obstack);
5816 s_e2 = BITMAP_ALLOC (s_obstack);
5823 /* Add N1 and N2 to their own set of equivalences to avoid
5824 duplicating the body of the loop just to check N1 and N2
5826 bitmap_set_bit (e1, SSA_NAME_VERSION (n1));
5827 bitmap_set_bit (e2, SSA_NAME_VERSION (n2));
5829 /* If the equivalence sets have a common intersection, then the two
5830 names can be compared without checking their ranges. */
5831 if (bitmap_intersect_p (e1, e2))
5833 bitmap_clear_bit (e1, SSA_NAME_VERSION (n1));
5834 bitmap_clear_bit (e2, SSA_NAME_VERSION (n2));
5836 return (comp == EQ_EXPR || comp == GE_EXPR || comp == LE_EXPR)
5838 : boolean_false_node;
5841 /* Start at -1. Set it to 0 if we do a comparison without relying
5842 on overflow, or 1 if all comparisons rely on overflow. */
5843 used_strict_overflow = -1;
5845 /* Otherwise, compare all the equivalent ranges. First, add N1 and
5846 N2 to their own set of equivalences to avoid duplicating the body
5847 of the loop just to check N1 and N2 ranges. */
5848 EXECUTE_IF_SET_IN_BITMAP (e1, 0, i1, bi1)
5850 value_range_t vr1 = get_vr_for_comparison (i1);
5852 t = retval = NULL_TREE;
5853 EXECUTE_IF_SET_IN_BITMAP (e2, 0, i2, bi2)
5857 value_range_t vr2 = get_vr_for_comparison (i2);
5859 t = compare_ranges (comp, &vr1, &vr2, &sop);
5862 /* If we get different answers from different members
5863 of the equivalence set this check must be in a dead
5864 code region. Folding it to a trap representation
5865 would be correct here. For now just return don't-know. */
5869 bitmap_clear_bit (e1, SSA_NAME_VERSION (n1));
5870 bitmap_clear_bit (e2, SSA_NAME_VERSION (n2));
5876 used_strict_overflow = 0;
5877 else if (used_strict_overflow < 0)
5878 used_strict_overflow = 1;
5884 bitmap_clear_bit (e1, SSA_NAME_VERSION (n1));
5885 bitmap_clear_bit (e2, SSA_NAME_VERSION (n2));
5886 if (used_strict_overflow > 0)
5887 *strict_overflow_p = true;
5892 /* None of the equivalent ranges are useful in computing this
5894 bitmap_clear_bit (e1, SSA_NAME_VERSION (n1));
5895 bitmap_clear_bit (e2, SSA_NAME_VERSION (n2));
5899 /* Helper function for vrp_evaluate_conditional_warnv. */
5902 vrp_evaluate_conditional_warnv_with_ops_using_ranges (enum tree_code code,
5904 bool * strict_overflow_p)
5906 value_range_t *vr0, *vr1;
5908 vr0 = (TREE_CODE (op0) == SSA_NAME) ? get_value_range (op0) : NULL;
5909 vr1 = (TREE_CODE (op1) == SSA_NAME) ? get_value_range (op1) : NULL;
5912 return compare_ranges (code, vr0, vr1, strict_overflow_p);
5913 else if (vr0 && vr1 == NULL)
5914 return compare_range_with_value (code, vr0, op1, strict_overflow_p);
5915 else if (vr0 == NULL && vr1)
5916 return (compare_range_with_value
5917 (swap_tree_comparison (code), vr1, op0, strict_overflow_p));
5921 /* Helper function for vrp_evaluate_conditional_warnv. */
5924 vrp_evaluate_conditional_warnv_with_ops (enum tree_code code, tree op0,
5925 tree op1, bool use_equiv_p,
5926 bool *strict_overflow_p, bool *only_ranges)
5930 *only_ranges = true;
5932 /* We only deal with integral and pointer types. */
5933 if (!INTEGRAL_TYPE_P (TREE_TYPE (op0))
5934 && !POINTER_TYPE_P (TREE_TYPE (op0)))
5940 && (ret = vrp_evaluate_conditional_warnv_with_ops_using_ranges
5941 (code, op0, op1, strict_overflow_p)))
5943 *only_ranges = false;
5944 if (TREE_CODE (op0) == SSA_NAME && TREE_CODE (op1) == SSA_NAME)
5945 return compare_names (code, op0, op1, strict_overflow_p);
5946 else if (TREE_CODE (op0) == SSA_NAME)
5947 return compare_name_with_value (code, op0, op1, strict_overflow_p);
5948 else if (TREE_CODE (op1) == SSA_NAME)
5949 return (compare_name_with_value
5950 (swap_tree_comparison (code), op1, op0, strict_overflow_p));
5953 return vrp_evaluate_conditional_warnv_with_ops_using_ranges (code, op0, op1,
5958 /* Given (CODE OP0 OP1) within STMT, try to simplify it based on value range
5959 information. Return NULL if the conditional can not be evaluated.
5960 The ranges of all the names equivalent with the operands in COND
5961 will be used when trying to compute the value. If the result is
5962 based on undefined signed overflow, issue a warning if
5966 vrp_evaluate_conditional (enum tree_code code, tree op0, tree op1, gimple stmt)
5972 /* Some passes and foldings leak constants with overflow flag set
5973 into the IL. Avoid doing wrong things with these and bail out. */
5974 if ((TREE_CODE (op0) == INTEGER_CST
5975 && TREE_OVERFLOW (op0))
5976 || (TREE_CODE (op1) == INTEGER_CST
5977 && TREE_OVERFLOW (op1)))
5981 ret = vrp_evaluate_conditional_warnv_with_ops (code, op0, op1, true, &sop,
5986 enum warn_strict_overflow_code wc;
5987 const char* warnmsg;
5989 if (is_gimple_min_invariant (ret))
5991 wc = WARN_STRICT_OVERFLOW_CONDITIONAL;
5992 warnmsg = G_("assuming signed overflow does not occur when "
5993 "simplifying conditional to constant");
5997 wc = WARN_STRICT_OVERFLOW_COMPARISON;
5998 warnmsg = G_("assuming signed overflow does not occur when "
5999 "simplifying conditional");
6002 if (issue_strict_overflow_warning (wc))
6004 location_t location;
6006 if (!gimple_has_location (stmt))
6007 location = input_location;
6009 location = gimple_location (stmt);
6010 warning_at (location, OPT_Wstrict_overflow, "%s", warnmsg);
6014 if (warn_type_limits
6015 && ret && only_ranges
6016 && TREE_CODE_CLASS (code) == tcc_comparison
6017 && TREE_CODE (op0) == SSA_NAME)
6019 /* If the comparison is being folded and the operand on the LHS
6020 is being compared against a constant value that is outside of
6021 the natural range of OP0's type, then the predicate will
6022 always fold regardless of the value of OP0. If -Wtype-limits
6023 was specified, emit a warning. */
6024 tree type = TREE_TYPE (op0);
6025 value_range_t *vr0 = get_value_range (op0);
6027 if (vr0->type != VR_VARYING
6028 && INTEGRAL_TYPE_P (type)
6029 && vrp_val_is_min (vr0->min)
6030 && vrp_val_is_max (vr0->max)
6031 && is_gimple_min_invariant (op1))
6033 location_t location;
6035 if (!gimple_has_location (stmt))
6036 location = input_location;
6038 location = gimple_location (stmt);
6040 warning_at (location, OPT_Wtype_limits,
6042 ? G_("comparison always false "
6043 "due to limited range of data type")
6044 : G_("comparison always true "
6045 "due to limited range of data type"));
6053 /* Visit conditional statement STMT. If we can determine which edge
6054 will be taken out of STMT's basic block, record it in
6055 *TAKEN_EDGE_P and return SSA_PROP_INTERESTING. Otherwise, return
6056 SSA_PROP_VARYING. */
6058 static enum ssa_prop_result
6059 vrp_visit_cond_stmt (gimple stmt, edge *taken_edge_p)
6064 *taken_edge_p = NULL;
6066 if (dump_file && (dump_flags & TDF_DETAILS))
6071 fprintf (dump_file, "\nVisiting conditional with predicate: ");
6072 print_gimple_stmt (dump_file, stmt, 0, 0);
6073 fprintf (dump_file, "\nWith known ranges\n");
6075 FOR_EACH_SSA_TREE_OPERAND (use, stmt, i, SSA_OP_USE)
6077 fprintf (dump_file, "\t");
6078 print_generic_expr (dump_file, use, 0);
6079 fprintf (dump_file, ": ");
6080 dump_value_range (dump_file, vr_value[SSA_NAME_VERSION (use)]);
6083 fprintf (dump_file, "\n");
6086 /* Compute the value of the predicate COND by checking the known
6087 ranges of each of its operands.
6089 Note that we cannot evaluate all the equivalent ranges here
6090 because those ranges may not yet be final and with the current
6091 propagation strategy, we cannot determine when the value ranges
6092 of the names in the equivalence set have changed.
6094 For instance, given the following code fragment
6098 i_14 = ASSERT_EXPR <i_5, i_5 != 0>
6102 Assume that on the first visit to i_14, i_5 has the temporary
6103 range [8, 8] because the second argument to the PHI function is
6104 not yet executable. We derive the range ~[0, 0] for i_14 and the
6105 equivalence set { i_5 }. So, when we visit 'if (i_14 == 1)' for
6106 the first time, since i_14 is equivalent to the range [8, 8], we
6107 determine that the predicate is always false.
6109 On the next round of propagation, i_13 is determined to be
6110 VARYING, which causes i_5 to drop down to VARYING. So, another
6111 visit to i_14 is scheduled. In this second visit, we compute the
6112 exact same range and equivalence set for i_14, namely ~[0, 0] and
6113 { i_5 }. But we did not have the previous range for i_5
6114 registered, so vrp_visit_assignment thinks that the range for
6115 i_14 has not changed. Therefore, the predicate 'if (i_14 == 1)'
6116 is not visited again, which stops propagation from visiting
6117 statements in the THEN clause of that if().
6119 To properly fix this we would need to keep the previous range
6120 value for the names in the equivalence set. This way we would've
6121 discovered that from one visit to the other i_5 changed from
6122 range [8, 8] to VR_VARYING.
6124 However, fixing this apparent limitation may not be worth the
6125 additional checking. Testing on several code bases (GCC, DLV,
6126 MICO, TRAMP3D and SPEC2000) showed that doing this results in
6127 4 more predicates folded in SPEC. */
6130 val = vrp_evaluate_conditional_warnv_with_ops (gimple_cond_code (stmt),
6131 gimple_cond_lhs (stmt),
6132 gimple_cond_rhs (stmt),
6137 *taken_edge_p = find_taken_edge (gimple_bb (stmt), val);
6140 if (dump_file && (dump_flags & TDF_DETAILS))
6142 "\nIgnoring predicate evaluation because "
6143 "it assumes that signed overflow is undefined");
6148 if (dump_file && (dump_flags & TDF_DETAILS))
6150 fprintf (dump_file, "\nPredicate evaluates to: ");
6151 if (val == NULL_TREE)
6152 fprintf (dump_file, "DON'T KNOW\n");
6154 print_generic_stmt (dump_file, val, 0);
6157 return (*taken_edge_p) ? SSA_PROP_INTERESTING : SSA_PROP_VARYING;
6160 /* Searches the case label vector VEC for the index *IDX of the CASE_LABEL
6161 that includes the value VAL. The search is restricted to the range
6162 [START_IDX, n - 1] where n is the size of VEC.
6164 If there is a CASE_LABEL for VAL, its index is placed in IDX and true is
6167 If there is no CASE_LABEL for VAL and there is one that is larger than VAL,
6168 it is placed in IDX and false is returned.
6170 If VAL is larger than any CASE_LABEL, n is placed on IDX and false is
6174 find_case_label_index (gimple stmt, size_t start_idx, tree val, size_t *idx)
6176 size_t n = gimple_switch_num_labels (stmt);
6179 /* Find case label for minimum of the value range or the next one.
6180 At each iteration we are searching in [low, high - 1]. */
6182 for (low = start_idx, high = n; high != low; )
6186 /* Note that i != high, so we never ask for n. */
6187 size_t i = (high + low) / 2;
6188 t = gimple_switch_label (stmt, i);
6190 /* Cache the result of comparing CASE_LOW and val. */
6191 cmp = tree_int_cst_compare (CASE_LOW (t), val);
6195 /* Ranges cannot be empty. */
6204 if (CASE_HIGH (t) != NULL
6205 && tree_int_cst_compare (CASE_HIGH (t), val) >= 0)
6217 /* Searches the case label vector VEC for the range of CASE_LABELs that is used
6218 for values between MIN and MAX. The first index is placed in MIN_IDX. The
6219 last index is placed in MAX_IDX. If the range of CASE_LABELs is empty
6220 then MAX_IDX < MIN_IDX.
6221 Returns true if the default label is not needed. */
6224 find_case_label_range (gimple stmt, tree min, tree max, size_t *min_idx,
6228 bool min_take_default = !find_case_label_index (stmt, 1, min, &i);
6229 bool max_take_default = !find_case_label_index (stmt, i, max, &j);
6233 && max_take_default)
6235 /* Only the default case label reached.
6236 Return an empty range. */
6243 bool take_default = min_take_default || max_take_default;
6247 if (max_take_default)
6250 /* If the case label range is continuous, we do not need
6251 the default case label. Verify that. */
6252 high = CASE_LOW (gimple_switch_label (stmt, i));
6253 if (CASE_HIGH (gimple_switch_label (stmt, i)))
6254 high = CASE_HIGH (gimple_switch_label (stmt, i));
6255 for (k = i + 1; k <= j; ++k)
6257 low = CASE_LOW (gimple_switch_label (stmt, k));
6258 if (!integer_onep (int_const_binop (MINUS_EXPR, low, high)))
6260 take_default = true;
6264 if (CASE_HIGH (gimple_switch_label (stmt, k)))
6265 high = CASE_HIGH (gimple_switch_label (stmt, k));
6270 return !take_default;
6274 /* Visit switch statement STMT. If we can determine which edge
6275 will be taken out of STMT's basic block, record it in
6276 *TAKEN_EDGE_P and return SSA_PROP_INTERESTING. Otherwise, return
6277 SSA_PROP_VARYING. */
6279 static enum ssa_prop_result
6280 vrp_visit_switch_stmt (gimple stmt, edge *taken_edge_p)
6284 size_t i = 0, j = 0;
6287 *taken_edge_p = NULL;
6288 op = gimple_switch_index (stmt);
6289 if (TREE_CODE (op) != SSA_NAME)
6290 return SSA_PROP_VARYING;
6292 vr = get_value_range (op);
6293 if (dump_file && (dump_flags & TDF_DETAILS))
6295 fprintf (dump_file, "\nVisiting switch expression with operand ");
6296 print_generic_expr (dump_file, op, 0);
6297 fprintf (dump_file, " with known range ");
6298 dump_value_range (dump_file, vr);
6299 fprintf (dump_file, "\n");
6302 if (vr->type != VR_RANGE
6303 || symbolic_range_p (vr))
6304 return SSA_PROP_VARYING;
6306 /* Find the single edge that is taken from the switch expression. */
6307 take_default = !find_case_label_range (stmt, vr->min, vr->max, &i, &j);
6309 /* Check if the range spans no CASE_LABEL. If so, we only reach the default
6313 gcc_assert (take_default);
6314 val = gimple_switch_default_label (stmt);
6318 /* Check if labels with index i to j and maybe the default label
6319 are all reaching the same label. */
6321 val = gimple_switch_label (stmt, i);
6323 && CASE_LABEL (gimple_switch_default_label (stmt))
6324 != CASE_LABEL (val))
6326 if (dump_file && (dump_flags & TDF_DETAILS))
6327 fprintf (dump_file, " not a single destination for this "
6329 return SSA_PROP_VARYING;
6331 for (++i; i <= j; ++i)
6333 if (CASE_LABEL (gimple_switch_label (stmt, i)) != CASE_LABEL (val))
6335 if (dump_file && (dump_flags & TDF_DETAILS))
6336 fprintf (dump_file, " not a single destination for this "
6338 return SSA_PROP_VARYING;
6343 *taken_edge_p = find_edge (gimple_bb (stmt),
6344 label_to_block (CASE_LABEL (val)));
6346 if (dump_file && (dump_flags & TDF_DETAILS))
6348 fprintf (dump_file, " will take edge to ");
6349 print_generic_stmt (dump_file, CASE_LABEL (val), 0);
6352 return SSA_PROP_INTERESTING;
6356 /* Evaluate statement STMT. If the statement produces a useful range,
6357 return SSA_PROP_INTERESTING and record the SSA name with the
6358 interesting range into *OUTPUT_P.
6360 If STMT is a conditional branch and we can determine its truth
6361 value, the taken edge is recorded in *TAKEN_EDGE_P.
6363 If STMT produces a varying value, return SSA_PROP_VARYING. */
6365 static enum ssa_prop_result
6366 vrp_visit_stmt (gimple stmt, edge *taken_edge_p, tree *output_p)
6371 if (dump_file && (dump_flags & TDF_DETAILS))
6373 fprintf (dump_file, "\nVisiting statement:\n");
6374 print_gimple_stmt (dump_file, stmt, 0, dump_flags);
6375 fprintf (dump_file, "\n");
6378 if (!stmt_interesting_for_vrp (stmt))
6379 gcc_assert (stmt_ends_bb_p (stmt));
6380 else if (is_gimple_assign (stmt) || is_gimple_call (stmt))
6382 /* In general, assignments with virtual operands are not useful
6383 for deriving ranges, with the obvious exception of calls to
6384 builtin functions. */
6385 if ((is_gimple_call (stmt)
6386 && gimple_call_fndecl (stmt) != NULL_TREE
6387 && DECL_IS_BUILTIN (gimple_call_fndecl (stmt)))
6388 || !gimple_vuse (stmt))
6389 return vrp_visit_assignment_or_call (stmt, output_p);
6391 else if (gimple_code (stmt) == GIMPLE_COND)
6392 return vrp_visit_cond_stmt (stmt, taken_edge_p);
6393 else if (gimple_code (stmt) == GIMPLE_SWITCH)
6394 return vrp_visit_switch_stmt (stmt, taken_edge_p);
6396 /* All other statements produce nothing of interest for VRP, so mark
6397 their outputs varying and prevent further simulation. */
6398 FOR_EACH_SSA_TREE_OPERAND (def, stmt, iter, SSA_OP_DEF)
6399 set_value_range_to_varying (get_value_range (def));
6401 return SSA_PROP_VARYING;
6405 /* Meet operation for value ranges. Given two value ranges VR0 and
6406 VR1, store in VR0 a range that contains both VR0 and VR1. This
6407 may not be the smallest possible such range. */
6410 vrp_meet (value_range_t *vr0, value_range_t *vr1)
6412 if (vr0->type == VR_UNDEFINED)
6414 copy_value_range (vr0, vr1);
6418 if (vr1->type == VR_UNDEFINED)
6420 /* Nothing to do. VR0 already has the resulting range. */
6424 if (vr0->type == VR_VARYING)
6426 /* Nothing to do. VR0 already has the resulting range. */
6430 if (vr1->type == VR_VARYING)
6432 set_value_range_to_varying (vr0);
6436 if (vr0->type == VR_RANGE && vr1->type == VR_RANGE)
6441 /* Compute the convex hull of the ranges. The lower limit of
6442 the new range is the minimum of the two ranges. If they
6443 cannot be compared, then give up. */
6444 cmp = compare_values (vr0->min, vr1->min);
6445 if (cmp == 0 || cmp == 1)
6452 /* Similarly, the upper limit of the new range is the maximum
6453 of the two ranges. If they cannot be compared, then
6455 cmp = compare_values (vr0->max, vr1->max);
6456 if (cmp == 0 || cmp == -1)
6463 /* Check for useless ranges. */
6464 if (INTEGRAL_TYPE_P (TREE_TYPE (min))
6465 && ((vrp_val_is_min (min) || is_overflow_infinity (min))
6466 && (vrp_val_is_max (max) || is_overflow_infinity (max))))
6469 /* The resulting set of equivalences is the intersection of
6471 if (vr0->equiv && vr1->equiv && vr0->equiv != vr1->equiv)
6472 bitmap_and_into (vr0->equiv, vr1->equiv);
6473 else if (vr0->equiv && !vr1->equiv)
6474 bitmap_clear (vr0->equiv);
6476 set_value_range (vr0, vr0->type, min, max, vr0->equiv);
6478 else if (vr0->type == VR_ANTI_RANGE && vr1->type == VR_ANTI_RANGE)
6480 /* Two anti-ranges meet only if their complements intersect.
6481 Only handle the case of identical ranges. */
6482 if (compare_values (vr0->min, vr1->min) == 0
6483 && compare_values (vr0->max, vr1->max) == 0
6484 && compare_values (vr0->min, vr0->max) == 0)
6486 /* The resulting set of equivalences is the intersection of
6488 if (vr0->equiv && vr1->equiv && vr0->equiv != vr1->equiv)
6489 bitmap_and_into (vr0->equiv, vr1->equiv);
6490 else if (vr0->equiv && !vr1->equiv)
6491 bitmap_clear (vr0->equiv);
6496 else if (vr0->type == VR_ANTI_RANGE || vr1->type == VR_ANTI_RANGE)
6498 /* For a numeric range [VAL1, VAL2] and an anti-range ~[VAL3, VAL4],
6499 only handle the case where the ranges have an empty intersection.
6500 The result of the meet operation is the anti-range. */
6501 if (!symbolic_range_p (vr0)
6502 && !symbolic_range_p (vr1)
6503 && !value_ranges_intersect_p (vr0, vr1))
6505 /* Copy most of VR1 into VR0. Don't copy VR1's equivalence
6506 set. We need to compute the intersection of the two
6507 equivalence sets. */
6508 if (vr1->type == VR_ANTI_RANGE)
6509 set_value_range (vr0, vr1->type, vr1->min, vr1->max, vr0->equiv);
6511 /* The resulting set of equivalences is the intersection of
6513 if (vr0->equiv && vr1->equiv && vr0->equiv != vr1->equiv)
6514 bitmap_and_into (vr0->equiv, vr1->equiv);
6515 else if (vr0->equiv && !vr1->equiv)
6516 bitmap_clear (vr0->equiv);
6527 /* Failed to find an efficient meet. Before giving up and setting
6528 the result to VARYING, see if we can at least derive a useful
6529 anti-range. FIXME, all this nonsense about distinguishing
6530 anti-ranges from ranges is necessary because of the odd
6531 semantics of range_includes_zero_p and friends. */
6532 if (!symbolic_range_p (vr0)
6533 && ((vr0->type == VR_RANGE && !range_includes_zero_p (vr0))
6534 || (vr0->type == VR_ANTI_RANGE && range_includes_zero_p (vr0)))
6535 && !symbolic_range_p (vr1)
6536 && ((vr1->type == VR_RANGE && !range_includes_zero_p (vr1))
6537 || (vr1->type == VR_ANTI_RANGE && range_includes_zero_p (vr1))))
6539 set_value_range_to_nonnull (vr0, TREE_TYPE (vr0->min));
6541 /* Since this meet operation did not result from the meeting of
6542 two equivalent names, VR0 cannot have any equivalences. */
6544 bitmap_clear (vr0->equiv);
6547 set_value_range_to_varying (vr0);
6551 /* Visit all arguments for PHI node PHI that flow through executable
6552 edges. If a valid value range can be derived from all the incoming
6553 value ranges, set a new range for the LHS of PHI. */
6555 static enum ssa_prop_result
6556 vrp_visit_phi_node (gimple phi)
6559 tree lhs = PHI_RESULT (phi);
6560 value_range_t *lhs_vr = get_value_range (lhs);
6561 value_range_t vr_result = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
6562 int edges, old_edges;
6565 if (dump_file && (dump_flags & TDF_DETAILS))
6567 fprintf (dump_file, "\nVisiting PHI node: ");
6568 print_gimple_stmt (dump_file, phi, 0, dump_flags);
6572 for (i = 0; i < gimple_phi_num_args (phi); i++)
6574 edge e = gimple_phi_arg_edge (phi, i);
6576 if (dump_file && (dump_flags & TDF_DETAILS))
6579 "\n Argument #%d (%d -> %d %sexecutable)\n",
6580 (int) i, e->src->index, e->dest->index,
6581 (e->flags & EDGE_EXECUTABLE) ? "" : "not ");
6584 if (e->flags & EDGE_EXECUTABLE)
6586 tree arg = PHI_ARG_DEF (phi, i);
6587 value_range_t vr_arg;
6591 if (TREE_CODE (arg) == SSA_NAME)
6593 vr_arg = *(get_value_range (arg));
6597 if (is_overflow_infinity (arg))
6599 arg = copy_node (arg);
6600 TREE_OVERFLOW (arg) = 0;
6603 vr_arg.type = VR_RANGE;
6606 vr_arg.equiv = NULL;
6609 if (dump_file && (dump_flags & TDF_DETAILS))
6611 fprintf (dump_file, "\t");
6612 print_generic_expr (dump_file, arg, dump_flags);
6613 fprintf (dump_file, "\n\tValue: ");
6614 dump_value_range (dump_file, &vr_arg);
6615 fprintf (dump_file, "\n");
6618 vrp_meet (&vr_result, &vr_arg);
6620 if (vr_result.type == VR_VARYING)
6625 if (vr_result.type == VR_VARYING)
6627 else if (vr_result.type == VR_UNDEFINED)
6630 old_edges = vr_phi_edge_counts[SSA_NAME_VERSION (lhs)];
6631 vr_phi_edge_counts[SSA_NAME_VERSION (lhs)] = edges;
6633 /* To prevent infinite iterations in the algorithm, derive ranges
6634 when the new value is slightly bigger or smaller than the
6635 previous one. We don't do this if we have seen a new executable
6636 edge; this helps us avoid an overflow infinity for conditionals
6637 which are not in a loop. */
6639 && gimple_phi_num_args (phi) > 1
6640 && edges == old_edges)
6642 int cmp_min = compare_values (lhs_vr->min, vr_result.min);
6643 int cmp_max = compare_values (lhs_vr->max, vr_result.max);
6645 /* For non VR_RANGE or for pointers fall back to varying if
6646 the range changed. */
6647 if ((lhs_vr->type != VR_RANGE || vr_result.type != VR_RANGE
6648 || POINTER_TYPE_P (TREE_TYPE (lhs)))
6649 && (cmp_min != 0 || cmp_max != 0))
6652 /* If the new minimum is smaller or larger than the previous
6653 one, go all the way to -INF. In the first case, to avoid
6654 iterating millions of times to reach -INF, and in the
6655 other case to avoid infinite bouncing between different
6657 if (cmp_min > 0 || cmp_min < 0)
6659 if (!needs_overflow_infinity (TREE_TYPE (vr_result.min))
6660 || !vrp_var_may_overflow (lhs, phi))
6661 vr_result.min = TYPE_MIN_VALUE (TREE_TYPE (vr_result.min));
6662 else if (supports_overflow_infinity (TREE_TYPE (vr_result.min)))
6664 negative_overflow_infinity (TREE_TYPE (vr_result.min));
6667 /* Similarly, if the new maximum is smaller or larger than
6668 the previous one, go all the way to +INF. */
6669 if (cmp_max < 0 || cmp_max > 0)
6671 if (!needs_overflow_infinity (TREE_TYPE (vr_result.max))
6672 || !vrp_var_may_overflow (lhs, phi))
6673 vr_result.max = TYPE_MAX_VALUE (TREE_TYPE (vr_result.max));
6674 else if (supports_overflow_infinity (TREE_TYPE (vr_result.max)))
6676 positive_overflow_infinity (TREE_TYPE (vr_result.max));
6679 /* If we dropped either bound to +-INF then if this is a loop
6680 PHI node SCEV may known more about its value-range. */
6681 if ((cmp_min > 0 || cmp_min < 0
6682 || cmp_max < 0 || cmp_max > 0)
6684 && (l = loop_containing_stmt (phi))
6685 && l->header == gimple_bb (phi))
6686 adjust_range_with_scev (&vr_result, l, phi, lhs);
6688 /* If we will end up with a (-INF, +INF) range, set it to
6689 VARYING. Same if the previous max value was invalid for
6690 the type and we end up with vr_result.min > vr_result.max. */
6691 if ((vrp_val_is_max (vr_result.max)
6692 && vrp_val_is_min (vr_result.min))
6693 || compare_values (vr_result.min,
6698 /* If the new range is different than the previous value, keep
6701 if (update_value_range (lhs, &vr_result))
6703 if (dump_file && (dump_flags & TDF_DETAILS))
6705 fprintf (dump_file, "Found new range for ");
6706 print_generic_expr (dump_file, lhs, 0);
6707 fprintf (dump_file, ": ");
6708 dump_value_range (dump_file, &vr_result);
6709 fprintf (dump_file, "\n\n");
6712 return SSA_PROP_INTERESTING;
6715 /* Nothing changed, don't add outgoing edges. */
6716 return SSA_PROP_NOT_INTERESTING;
6718 /* No match found. Set the LHS to VARYING. */
6720 set_value_range_to_varying (lhs_vr);
6721 return SSA_PROP_VARYING;
6724 /* Simplify boolean operations if the source is known
6725 to be already a boolean. */
6727 simplify_truth_ops_using_ranges (gimple_stmt_iterator *gsi, gimple stmt)
6729 enum tree_code rhs_code = gimple_assign_rhs_code (stmt);
6731 bool need_conversion;
6733 /* We handle only !=/== case here. */
6734 gcc_assert (rhs_code == EQ_EXPR || rhs_code == NE_EXPR);
6736 op0 = gimple_assign_rhs1 (stmt);
6737 if (!op_with_boolean_value_range_p (op0))
6740 op1 = gimple_assign_rhs2 (stmt);
6741 if (!op_with_boolean_value_range_p (op1))
6744 /* Reduce number of cases to handle to NE_EXPR. As there is no
6745 BIT_XNOR_EXPR we cannot replace A == B with a single statement. */
6746 if (rhs_code == EQ_EXPR)
6748 if (TREE_CODE (op1) == INTEGER_CST)
6749 op1 = int_const_binop (BIT_XOR_EXPR, op1, integer_one_node);
6754 lhs = gimple_assign_lhs (stmt);
6756 = !useless_type_conversion_p (TREE_TYPE (lhs), TREE_TYPE (op0));
6758 /* Make sure to not sign-extend a 1-bit 1 when converting the result. */
6760 && !TYPE_UNSIGNED (TREE_TYPE (op0))
6761 && TYPE_PRECISION (TREE_TYPE (op0)) == 1
6762 && TYPE_PRECISION (TREE_TYPE (lhs)) > 1)
6765 /* For A != 0 we can substitute A itself. */
6766 if (integer_zerop (op1))
6767 gimple_assign_set_rhs_with_ops (gsi,
6769 ? NOP_EXPR : TREE_CODE (op0),
6771 /* For A != B we substitute A ^ B. Either with conversion. */
6772 else if (need_conversion)
6775 tree tem = create_tmp_reg (TREE_TYPE (op0), NULL);
6776 newop = gimple_build_assign_with_ops (BIT_XOR_EXPR, tem, op0, op1);
6777 tem = make_ssa_name (tem, newop);
6778 gimple_assign_set_lhs (newop, tem);
6779 gsi_insert_before (gsi, newop, GSI_SAME_STMT);
6780 update_stmt (newop);
6781 gimple_assign_set_rhs_with_ops (gsi, NOP_EXPR, tem, NULL_TREE);
6785 gimple_assign_set_rhs_with_ops (gsi, BIT_XOR_EXPR, op0, op1);
6786 update_stmt (gsi_stmt (*gsi));
6791 /* Simplify a division or modulo operator to a right shift or
6792 bitwise and if the first operand is unsigned or is greater
6793 than zero and the second operand is an exact power of two. */
6796 simplify_div_or_mod_using_ranges (gimple stmt)
6798 enum tree_code rhs_code = gimple_assign_rhs_code (stmt);
6800 tree op0 = gimple_assign_rhs1 (stmt);
6801 tree op1 = gimple_assign_rhs2 (stmt);
6802 value_range_t *vr = get_value_range (gimple_assign_rhs1 (stmt));
6804 if (TYPE_UNSIGNED (TREE_TYPE (op0)))
6806 val = integer_one_node;
6812 val = compare_range_with_value (GE_EXPR, vr, integer_zero_node, &sop);
6816 && integer_onep (val)
6817 && issue_strict_overflow_warning (WARN_STRICT_OVERFLOW_MISC))
6819 location_t location;
6821 if (!gimple_has_location (stmt))
6822 location = input_location;
6824 location = gimple_location (stmt);
6825 warning_at (location, OPT_Wstrict_overflow,
6826 "assuming signed overflow does not occur when "
6827 "simplifying %</%> or %<%%%> to %<>>%> or %<&%>");
6831 if (val && integer_onep (val))
6835 if (rhs_code == TRUNC_DIV_EXPR)
6837 t = build_int_cst (integer_type_node, tree_log2 (op1));
6838 gimple_assign_set_rhs_code (stmt, RSHIFT_EXPR);
6839 gimple_assign_set_rhs1 (stmt, op0);
6840 gimple_assign_set_rhs2 (stmt, t);
6844 t = build_int_cst (TREE_TYPE (op1), 1);
6845 t = int_const_binop (MINUS_EXPR, op1, t);
6846 t = fold_convert (TREE_TYPE (op0), t);
6848 gimple_assign_set_rhs_code (stmt, BIT_AND_EXPR);
6849 gimple_assign_set_rhs1 (stmt, op0);
6850 gimple_assign_set_rhs2 (stmt, t);
6860 /* If the operand to an ABS_EXPR is >= 0, then eliminate the
6861 ABS_EXPR. If the operand is <= 0, then simplify the
6862 ABS_EXPR into a NEGATE_EXPR. */
6865 simplify_abs_using_ranges (gimple stmt)
6868 tree op = gimple_assign_rhs1 (stmt);
6869 tree type = TREE_TYPE (op);
6870 value_range_t *vr = get_value_range (op);
6872 if (TYPE_UNSIGNED (type))
6874 val = integer_zero_node;
6880 val = compare_range_with_value (LE_EXPR, vr, integer_zero_node, &sop);
6884 val = compare_range_with_value (GE_EXPR, vr, integer_zero_node,
6889 if (integer_zerop (val))
6890 val = integer_one_node;
6891 else if (integer_onep (val))
6892 val = integer_zero_node;
6897 && (integer_onep (val) || integer_zerop (val)))
6899 if (sop && issue_strict_overflow_warning (WARN_STRICT_OVERFLOW_MISC))
6901 location_t location;
6903 if (!gimple_has_location (stmt))
6904 location = input_location;
6906 location = gimple_location (stmt);
6907 warning_at (location, OPT_Wstrict_overflow,
6908 "assuming signed overflow does not occur when "
6909 "simplifying %<abs (X)%> to %<X%> or %<-X%>");
6912 gimple_assign_set_rhs1 (stmt, op);
6913 if (integer_onep (val))
6914 gimple_assign_set_rhs_code (stmt, NEGATE_EXPR);
6916 gimple_assign_set_rhs_code (stmt, SSA_NAME);
6925 /* Optimize away redundant BIT_AND_EXPR and BIT_IOR_EXPR.
6926 If all the bits that are being cleared by & are already
6927 known to be zero from VR, or all the bits that are being
6928 set by | are already known to be one from VR, the bit
6929 operation is redundant. */
6932 simplify_bit_ops_using_ranges (gimple_stmt_iterator *gsi, gimple stmt)
6934 tree op0 = gimple_assign_rhs1 (stmt);
6935 tree op1 = gimple_assign_rhs2 (stmt);
6936 tree op = NULL_TREE;
6937 value_range_t vr0 = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
6938 value_range_t vr1 = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
6939 double_int may_be_nonzero0, may_be_nonzero1;
6940 double_int must_be_nonzero0, must_be_nonzero1;
6943 if (TREE_CODE (op0) == SSA_NAME)
6944 vr0 = *(get_value_range (op0));
6945 else if (is_gimple_min_invariant (op0))
6946 set_value_range_to_value (&vr0, op0, NULL);
6950 if (TREE_CODE (op1) == SSA_NAME)
6951 vr1 = *(get_value_range (op1));
6952 else if (is_gimple_min_invariant (op1))
6953 set_value_range_to_value (&vr1, op1, NULL);
6957 if (!zero_nonzero_bits_from_vr (&vr0, &may_be_nonzero0, &must_be_nonzero0))
6959 if (!zero_nonzero_bits_from_vr (&vr1, &may_be_nonzero1, &must_be_nonzero1))
6962 switch (gimple_assign_rhs_code (stmt))
6965 mask = double_int_and_not (may_be_nonzero0, must_be_nonzero1);
6966 if (double_int_zero_p (mask))
6971 mask = double_int_and_not (may_be_nonzero1, must_be_nonzero0);
6972 if (double_int_zero_p (mask))
6979 mask = double_int_and_not (may_be_nonzero0, must_be_nonzero1);
6980 if (double_int_zero_p (mask))
6985 mask = double_int_and_not (may_be_nonzero1, must_be_nonzero0);
6986 if (double_int_zero_p (mask))
6996 if (op == NULL_TREE)
6999 gimple_assign_set_rhs_with_ops (gsi, TREE_CODE (op), op, NULL);
7000 update_stmt (gsi_stmt (*gsi));
7004 /* We are comparing trees OP0 and OP1 using COND_CODE. OP0 has
7005 a known value range VR.
7007 If there is one and only one value which will satisfy the
7008 conditional, then return that value. Else return NULL. */
7011 test_for_singularity (enum tree_code cond_code, tree op0,
7012 tree op1, value_range_t *vr)
7017 /* Extract minimum/maximum values which satisfy the
7018 the conditional as it was written. */
7019 if (cond_code == LE_EXPR || cond_code == LT_EXPR)
7021 /* This should not be negative infinity; there is no overflow
7023 min = TYPE_MIN_VALUE (TREE_TYPE (op0));
7026 if (cond_code == LT_EXPR && !is_overflow_infinity (max))
7028 tree one = build_int_cst (TREE_TYPE (op0), 1);
7029 max = fold_build2 (MINUS_EXPR, TREE_TYPE (op0), max, one);
7031 TREE_NO_WARNING (max) = 1;
7034 else if (cond_code == GE_EXPR || cond_code == GT_EXPR)
7036 /* This should not be positive infinity; there is no overflow
7038 max = TYPE_MAX_VALUE (TREE_TYPE (op0));
7041 if (cond_code == GT_EXPR && !is_overflow_infinity (min))
7043 tree one = build_int_cst (TREE_TYPE (op0), 1);
7044 min = fold_build2 (PLUS_EXPR, TREE_TYPE (op0), min, one);
7046 TREE_NO_WARNING (min) = 1;
7050 /* Now refine the minimum and maximum values using any
7051 value range information we have for op0. */
7054 if (compare_values (vr->min, min) == 1)
7056 if (compare_values (vr->max, max) == -1)
7059 /* If the new min/max values have converged to a single value,
7060 then there is only one value which can satisfy the condition,
7061 return that value. */
7062 if (operand_equal_p (min, max, 0) && is_gimple_min_invariant (min))
7068 /* Simplify a conditional using a relational operator to an equality
7069 test if the range information indicates only one value can satisfy
7070 the original conditional. */
7073 simplify_cond_using_ranges (gimple stmt)
7075 tree op0 = gimple_cond_lhs (stmt);
7076 tree op1 = gimple_cond_rhs (stmt);
7077 enum tree_code cond_code = gimple_cond_code (stmt);
7079 if (cond_code != NE_EXPR
7080 && cond_code != EQ_EXPR
7081 && TREE_CODE (op0) == SSA_NAME
7082 && INTEGRAL_TYPE_P (TREE_TYPE (op0))
7083 && is_gimple_min_invariant (op1))
7085 value_range_t *vr = get_value_range (op0);
7087 /* If we have range information for OP0, then we might be
7088 able to simplify this conditional. */
7089 if (vr->type == VR_RANGE)
7091 tree new_tree = test_for_singularity (cond_code, op0, op1, vr);
7097 fprintf (dump_file, "Simplified relational ");
7098 print_gimple_stmt (dump_file, stmt, 0, 0);
7099 fprintf (dump_file, " into ");
7102 gimple_cond_set_code (stmt, EQ_EXPR);
7103 gimple_cond_set_lhs (stmt, op0);
7104 gimple_cond_set_rhs (stmt, new_tree);
7110 print_gimple_stmt (dump_file, stmt, 0, 0);
7111 fprintf (dump_file, "\n");
7117 /* Try again after inverting the condition. We only deal
7118 with integral types here, so no need to worry about
7119 issues with inverting FP comparisons. */
7120 cond_code = invert_tree_comparison (cond_code, false);
7121 new_tree = test_for_singularity (cond_code, op0, op1, vr);
7127 fprintf (dump_file, "Simplified relational ");
7128 print_gimple_stmt (dump_file, stmt, 0, 0);
7129 fprintf (dump_file, " into ");
7132 gimple_cond_set_code (stmt, NE_EXPR);
7133 gimple_cond_set_lhs (stmt, op0);
7134 gimple_cond_set_rhs (stmt, new_tree);
7140 print_gimple_stmt (dump_file, stmt, 0, 0);
7141 fprintf (dump_file, "\n");
7152 /* Simplify a switch statement using the value range of the switch
7156 simplify_switch_using_ranges (gimple stmt)
7158 tree op = gimple_switch_index (stmt);
7163 size_t i = 0, j = 0, n, n2;
7167 if (TREE_CODE (op) == SSA_NAME)
7169 vr = get_value_range (op);
7171 /* We can only handle integer ranges. */
7172 if (vr->type != VR_RANGE
7173 || symbolic_range_p (vr))
7176 /* Find case label for min/max of the value range. */
7177 take_default = !find_case_label_range (stmt, vr->min, vr->max, &i, &j);
7179 else if (TREE_CODE (op) == INTEGER_CST)
7181 take_default = !find_case_label_index (stmt, 1, op, &i);
7195 n = gimple_switch_num_labels (stmt);
7197 /* Bail out if this is just all edges taken. */
7203 /* Build a new vector of taken case labels. */
7204 vec2 = make_tree_vec (j - i + 1 + (int)take_default);
7207 /* Add the default edge, if necessary. */
7209 TREE_VEC_ELT (vec2, n2++) = gimple_switch_default_label (stmt);
7211 for (; i <= j; ++i, ++n2)
7212 TREE_VEC_ELT (vec2, n2) = gimple_switch_label (stmt, i);
7214 /* Mark needed edges. */
7215 for (i = 0; i < n2; ++i)
7217 e = find_edge (gimple_bb (stmt),
7218 label_to_block (CASE_LABEL (TREE_VEC_ELT (vec2, i))));
7219 e->aux = (void *)-1;
7222 /* Queue not needed edges for later removal. */
7223 FOR_EACH_EDGE (e, ei, gimple_bb (stmt)->succs)
7225 if (e->aux == (void *)-1)
7231 if (dump_file && (dump_flags & TDF_DETAILS))
7233 fprintf (dump_file, "removing unreachable case label\n");
7235 VEC_safe_push (edge, heap, to_remove_edges, e);
7236 e->flags &= ~EDGE_EXECUTABLE;
7239 /* And queue an update for the stmt. */
7242 VEC_safe_push (switch_update, heap, to_update_switch_stmts, &su);
7246 /* Simplify an integral conversion from an SSA name in STMT. */
7249 simplify_conversion_using_ranges (gimple stmt)
7251 tree innerop, middleop, finaltype;
7253 value_range_t *innervr;
7254 double_int innermin, innermax, middlemin, middlemax;
7256 finaltype = TREE_TYPE (gimple_assign_lhs (stmt));
7257 if (!INTEGRAL_TYPE_P (finaltype))
7259 middleop = gimple_assign_rhs1 (stmt);
7260 def_stmt = SSA_NAME_DEF_STMT (middleop);
7261 if (!is_gimple_assign (def_stmt)
7262 || !CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (def_stmt)))
7264 innerop = gimple_assign_rhs1 (def_stmt);
7265 if (TREE_CODE (innerop) != SSA_NAME)
7268 /* Get the value-range of the inner operand. */
7269 innervr = get_value_range (innerop);
7270 if (innervr->type != VR_RANGE
7271 || TREE_CODE (innervr->min) != INTEGER_CST
7272 || TREE_CODE (innervr->max) != INTEGER_CST)
7275 /* Simulate the conversion chain to check if the result is equal if
7276 the middle conversion is removed. */
7277 innermin = tree_to_double_int (innervr->min);
7278 innermax = tree_to_double_int (innervr->max);
7279 middlemin = double_int_ext (innermin, TYPE_PRECISION (TREE_TYPE (middleop)),
7280 TYPE_UNSIGNED (TREE_TYPE (middleop)));
7281 middlemax = double_int_ext (innermax, TYPE_PRECISION (TREE_TYPE (middleop)),
7282 TYPE_UNSIGNED (TREE_TYPE (middleop)));
7283 /* If the middle values do not represent a proper range fail. */
7284 if (double_int_cmp (middlemin, middlemax,
7285 TYPE_UNSIGNED (TREE_TYPE (middleop))) > 0)
7287 if (!double_int_equal_p (double_int_ext (middlemin,
7288 TYPE_PRECISION (finaltype),
7289 TYPE_UNSIGNED (finaltype)),
7290 double_int_ext (innermin,
7291 TYPE_PRECISION (finaltype),
7292 TYPE_UNSIGNED (finaltype)))
7293 || !double_int_equal_p (double_int_ext (middlemax,
7294 TYPE_PRECISION (finaltype),
7295 TYPE_UNSIGNED (finaltype)),
7296 double_int_ext (innermax,
7297 TYPE_PRECISION (finaltype),
7298 TYPE_UNSIGNED (finaltype))))
7301 gimple_assign_set_rhs1 (stmt, innerop);
7306 /* Return whether the value range *VR fits in an integer type specified
7307 by PRECISION and UNSIGNED_P. */
7310 range_fits_type_p (value_range_t *vr, unsigned precision, bool unsigned_p)
7313 unsigned src_precision;
7316 /* We can only handle integral and pointer types. */
7317 src_type = TREE_TYPE (vr->min);
7318 if (!INTEGRAL_TYPE_P (src_type)
7319 && !POINTER_TYPE_P (src_type))
7322 /* An extension is always fine, so is an identity transform. */
7323 src_precision = TYPE_PRECISION (TREE_TYPE (vr->min));
7324 if (src_precision < precision
7325 || (src_precision == precision
7326 && TYPE_UNSIGNED (src_type) == unsigned_p))
7329 /* Now we can only handle ranges with constant bounds. */
7330 if (vr->type != VR_RANGE
7331 || TREE_CODE (vr->min) != INTEGER_CST
7332 || TREE_CODE (vr->max) != INTEGER_CST)
7335 /* For precision-preserving sign-changes the MSB of the double-int
7337 if (src_precision == precision
7338 && (TREE_INT_CST_HIGH (vr->min) | TREE_INT_CST_HIGH (vr->max)) < 0)
7341 /* Then we can perform the conversion on both ends and compare
7342 the result for equality. */
7343 tem = double_int_ext (tree_to_double_int (vr->min), precision, unsigned_p);
7344 if (!double_int_equal_p (tree_to_double_int (vr->min), tem))
7346 tem = double_int_ext (tree_to_double_int (vr->max), precision, unsigned_p);
7347 if (!double_int_equal_p (tree_to_double_int (vr->max), tem))
7353 /* Simplify a conversion from integral SSA name to float in STMT. */
7356 simplify_float_conversion_using_ranges (gimple_stmt_iterator *gsi, gimple stmt)
7358 tree rhs1 = gimple_assign_rhs1 (stmt);
7359 value_range_t *vr = get_value_range (rhs1);
7360 enum machine_mode fltmode = TYPE_MODE (TREE_TYPE (gimple_assign_lhs (stmt)));
7361 enum machine_mode mode;
7365 /* We can only handle constant ranges. */
7366 if (vr->type != VR_RANGE
7367 || TREE_CODE (vr->min) != INTEGER_CST
7368 || TREE_CODE (vr->max) != INTEGER_CST)
7371 /* First check if we can use a signed type in place of an unsigned. */
7372 if (TYPE_UNSIGNED (TREE_TYPE (rhs1))
7373 && (can_float_p (fltmode, TYPE_MODE (TREE_TYPE (rhs1)), 0)
7374 != CODE_FOR_nothing)
7375 && range_fits_type_p (vr, GET_MODE_PRECISION
7376 (TYPE_MODE (TREE_TYPE (rhs1))), 0))
7377 mode = TYPE_MODE (TREE_TYPE (rhs1));
7378 /* If we can do the conversion in the current input mode do nothing. */
7379 else if (can_float_p (fltmode, TYPE_MODE (TREE_TYPE (rhs1)),
7380 TYPE_UNSIGNED (TREE_TYPE (rhs1))))
7382 /* Otherwise search for a mode we can use, starting from the narrowest
7383 integer mode available. */
7386 mode = GET_CLASS_NARROWEST_MODE (MODE_INT);
7389 /* If we cannot do a signed conversion to float from mode
7390 or if the value-range does not fit in the signed type
7391 try with a wider mode. */
7392 if (can_float_p (fltmode, mode, 0) != CODE_FOR_nothing
7393 && range_fits_type_p (vr, GET_MODE_PRECISION (mode), 0))
7396 mode = GET_MODE_WIDER_MODE (mode);
7397 /* But do not widen the input. Instead leave that to the
7398 optabs expansion code. */
7399 if (GET_MODE_PRECISION (mode) > TYPE_PRECISION (TREE_TYPE (rhs1)))
7402 while (mode != VOIDmode);
7403 if (mode == VOIDmode)
7407 /* It works, insert a truncation or sign-change before the
7408 float conversion. */
7409 tem = create_tmp_var (build_nonstandard_integer_type
7410 (GET_MODE_PRECISION (mode), 0), NULL);
7411 conv = gimple_build_assign_with_ops (NOP_EXPR, tem, rhs1, NULL_TREE);
7412 tem = make_ssa_name (tem, conv);
7413 gimple_assign_set_lhs (conv, tem);
7414 gsi_insert_before (gsi, conv, GSI_SAME_STMT);
7415 gimple_assign_set_rhs1 (stmt, tem);
7421 /* Simplify STMT using ranges if possible. */
7424 simplify_stmt_using_ranges (gimple_stmt_iterator *gsi)
7426 gimple stmt = gsi_stmt (*gsi);
7427 if (is_gimple_assign (stmt))
7429 enum tree_code rhs_code = gimple_assign_rhs_code (stmt);
7430 tree rhs1 = gimple_assign_rhs1 (stmt);
7436 /* Transform EQ_EXPR, NE_EXPR into BIT_XOR_EXPR or identity
7437 if the RHS is zero or one, and the LHS are known to be boolean
7439 if (INTEGRAL_TYPE_P (TREE_TYPE (rhs1)))
7440 return simplify_truth_ops_using_ranges (gsi, stmt);
7443 /* Transform TRUNC_DIV_EXPR and TRUNC_MOD_EXPR into RSHIFT_EXPR
7444 and BIT_AND_EXPR respectively if the first operand is greater
7445 than zero and the second operand is an exact power of two. */
7446 case TRUNC_DIV_EXPR:
7447 case TRUNC_MOD_EXPR:
7448 if (INTEGRAL_TYPE_P (TREE_TYPE (rhs1))
7449 && integer_pow2p (gimple_assign_rhs2 (stmt)))
7450 return simplify_div_or_mod_using_ranges (stmt);
7453 /* Transform ABS (X) into X or -X as appropriate. */
7455 if (TREE_CODE (rhs1) == SSA_NAME
7456 && INTEGRAL_TYPE_P (TREE_TYPE (rhs1)))
7457 return simplify_abs_using_ranges (stmt);
7462 /* Optimize away BIT_AND_EXPR and BIT_IOR_EXPR
7463 if all the bits being cleared are already cleared or
7464 all the bits being set are already set. */
7465 if (INTEGRAL_TYPE_P (TREE_TYPE (rhs1)))
7466 return simplify_bit_ops_using_ranges (gsi, stmt);
7470 if (TREE_CODE (rhs1) == SSA_NAME
7471 && INTEGRAL_TYPE_P (TREE_TYPE (rhs1)))
7472 return simplify_conversion_using_ranges (stmt);
7476 if (TREE_CODE (rhs1) == SSA_NAME
7477 && INTEGRAL_TYPE_P (TREE_TYPE (rhs1)))
7478 return simplify_float_conversion_using_ranges (gsi, stmt);
7485 else if (gimple_code (stmt) == GIMPLE_COND)
7486 return simplify_cond_using_ranges (stmt);
7487 else if (gimple_code (stmt) == GIMPLE_SWITCH)
7488 return simplify_switch_using_ranges (stmt);
7493 /* If the statement pointed by SI has a predicate whose value can be
7494 computed using the value range information computed by VRP, compute
7495 its value and return true. Otherwise, return false. */
7498 fold_predicate_in (gimple_stmt_iterator *si)
7500 bool assignment_p = false;
7502 gimple stmt = gsi_stmt (*si);
7504 if (is_gimple_assign (stmt)
7505 && TREE_CODE_CLASS (gimple_assign_rhs_code (stmt)) == tcc_comparison)
7507 assignment_p = true;
7508 val = vrp_evaluate_conditional (gimple_assign_rhs_code (stmt),
7509 gimple_assign_rhs1 (stmt),
7510 gimple_assign_rhs2 (stmt),
7513 else if (gimple_code (stmt) == GIMPLE_COND)
7514 val = vrp_evaluate_conditional (gimple_cond_code (stmt),
7515 gimple_cond_lhs (stmt),
7516 gimple_cond_rhs (stmt),
7524 val = fold_convert (gimple_expr_type (stmt), val);
7528 fprintf (dump_file, "Folding predicate ");
7529 print_gimple_expr (dump_file, stmt, 0, 0);
7530 fprintf (dump_file, " to ");
7531 print_generic_expr (dump_file, val, 0);
7532 fprintf (dump_file, "\n");
7535 if (is_gimple_assign (stmt))
7536 gimple_assign_set_rhs_from_tree (si, val);
7539 gcc_assert (gimple_code (stmt) == GIMPLE_COND);
7540 if (integer_zerop (val))
7541 gimple_cond_make_false (stmt);
7542 else if (integer_onep (val))
7543 gimple_cond_make_true (stmt);
7554 /* Callback for substitute_and_fold folding the stmt at *SI. */
7557 vrp_fold_stmt (gimple_stmt_iterator *si)
7559 if (fold_predicate_in (si))
7562 return simplify_stmt_using_ranges (si);
7565 /* Stack of dest,src equivalency pairs that need to be restored after
7566 each attempt to thread a block's incoming edge to an outgoing edge.
7568 A NULL entry is used to mark the end of pairs which need to be
7570 static VEC(tree,heap) *stack;
7572 /* A trivial wrapper so that we can present the generic jump threading
7573 code with a simple API for simplifying statements. STMT is the
7574 statement we want to simplify, WITHIN_STMT provides the location
7575 for any overflow warnings. */
7578 simplify_stmt_for_jump_threading (gimple stmt, gimple within_stmt)
7580 /* We only use VRP information to simplify conditionals. This is
7581 overly conservative, but it's unclear if doing more would be
7582 worth the compile time cost. */
7583 if (gimple_code (stmt) != GIMPLE_COND)
7586 return vrp_evaluate_conditional (gimple_cond_code (stmt),
7587 gimple_cond_lhs (stmt),
7588 gimple_cond_rhs (stmt), within_stmt);
7591 /* Blocks which have more than one predecessor and more than
7592 one successor present jump threading opportunities, i.e.,
7593 when the block is reached from a specific predecessor, we
7594 may be able to determine which of the outgoing edges will
7595 be traversed. When this optimization applies, we are able
7596 to avoid conditionals at runtime and we may expose secondary
7597 optimization opportunities.
7599 This routine is effectively a driver for the generic jump
7600 threading code. It basically just presents the generic code
7601 with edges that may be suitable for jump threading.
7603 Unlike DOM, we do not iterate VRP if jump threading was successful.
7604 While iterating may expose new opportunities for VRP, it is expected
7605 those opportunities would be very limited and the compile time cost
7606 to expose those opportunities would be significant.
7608 As jump threading opportunities are discovered, they are registered
7609 for later realization. */
7612 identify_jump_threads (void)
7619 /* Ugh. When substituting values earlier in this pass we can
7620 wipe the dominance information. So rebuild the dominator
7621 information as we need it within the jump threading code. */
7622 calculate_dominance_info (CDI_DOMINATORS);
7624 /* We do not allow VRP information to be used for jump threading
7625 across a back edge in the CFG. Otherwise it becomes too
7626 difficult to avoid eliminating loop exit tests. Of course
7627 EDGE_DFS_BACK is not accurate at this time so we have to
7629 mark_dfs_back_edges ();
7631 /* Do not thread across edges we are about to remove. Just marking
7632 them as EDGE_DFS_BACK will do. */
7633 FOR_EACH_VEC_ELT (edge, to_remove_edges, i, e)
7634 e->flags |= EDGE_DFS_BACK;
7636 /* Allocate our unwinder stack to unwind any temporary equivalences
7637 that might be recorded. */
7638 stack = VEC_alloc (tree, heap, 20);
7640 /* To avoid lots of silly node creation, we create a single
7641 conditional and just modify it in-place when attempting to
7643 dummy = gimple_build_cond (EQ_EXPR,
7644 integer_zero_node, integer_zero_node,
7647 /* Walk through all the blocks finding those which present a
7648 potential jump threading opportunity. We could set this up
7649 as a dominator walker and record data during the walk, but
7650 I doubt it's worth the effort for the classes of jump
7651 threading opportunities we are trying to identify at this
7652 point in compilation. */
7657 /* If the generic jump threading code does not find this block
7658 interesting, then there is nothing to do. */
7659 if (! potentially_threadable_block (bb))
7662 /* We only care about blocks ending in a COND_EXPR. While there
7663 may be some value in handling SWITCH_EXPR here, I doubt it's
7664 terribly important. */
7665 last = gsi_stmt (gsi_last_bb (bb));
7667 /* We're basically looking for a switch or any kind of conditional with
7668 integral or pointer type arguments. Note the type of the second
7669 argument will be the same as the first argument, so no need to
7670 check it explicitly. */
7671 if (gimple_code (last) == GIMPLE_SWITCH
7672 || (gimple_code (last) == GIMPLE_COND
7673 && TREE_CODE (gimple_cond_lhs (last)) == SSA_NAME
7674 && (INTEGRAL_TYPE_P (TREE_TYPE (gimple_cond_lhs (last)))
7675 || POINTER_TYPE_P (TREE_TYPE (gimple_cond_lhs (last))))
7676 && (TREE_CODE (gimple_cond_rhs (last)) == SSA_NAME
7677 || is_gimple_min_invariant (gimple_cond_rhs (last)))))
7681 /* We've got a block with multiple predecessors and multiple
7682 successors which also ends in a suitable conditional or
7683 switch statement. For each predecessor, see if we can thread
7684 it to a specific successor. */
7685 FOR_EACH_EDGE (e, ei, bb->preds)
7687 /* Do not thread across back edges or abnormal edges
7689 if (e->flags & (EDGE_DFS_BACK | EDGE_COMPLEX))
7692 thread_across_edge (dummy, e, true, &stack,
7693 simplify_stmt_for_jump_threading);
7698 /* We do not actually update the CFG or SSA graphs at this point as
7699 ASSERT_EXPRs are still in the IL and cfg cleanup code does not yet
7700 handle ASSERT_EXPRs gracefully. */
7703 /* We identified all the jump threading opportunities earlier, but could
7704 not transform the CFG at that time. This routine transforms the
7705 CFG and arranges for the dominator tree to be rebuilt if necessary.
7707 Note the SSA graph update will occur during the normal TODO
7708 processing by the pass manager. */
7710 finalize_jump_threads (void)
7712 thread_through_all_blocks (false);
7713 VEC_free (tree, heap, stack);
7717 /* Traverse all the blocks folding conditionals with known ranges. */
7724 values_propagated = true;
7728 fprintf (dump_file, "\nValue ranges after VRP:\n\n");
7729 dump_all_value_ranges (dump_file);
7730 fprintf (dump_file, "\n");
7733 substitute_and_fold (op_with_constant_singleton_value_range,
7734 vrp_fold_stmt, false);
7736 if (warn_array_bounds)
7737 check_all_array_refs ();
7739 /* We must identify jump threading opportunities before we release
7740 the datastructures built by VRP. */
7741 identify_jump_threads ();
7743 /* Free allocated memory. */
7744 for (i = 0; i < num_vr_values; i++)
7747 BITMAP_FREE (vr_value[i]->equiv);
7752 free (vr_phi_edge_counts);
7754 /* So that we can distinguish between VRP data being available
7755 and not available. */
7757 vr_phi_edge_counts = NULL;
7761 /* Main entry point to VRP (Value Range Propagation). This pass is
7762 loosely based on J. R. C. Patterson, ``Accurate Static Branch
7763 Prediction by Value Range Propagation,'' in SIGPLAN Conference on
7764 Programming Language Design and Implementation, pp. 67-78, 1995.
7765 Also available at http://citeseer.ist.psu.edu/patterson95accurate.html
7767 This is essentially an SSA-CCP pass modified to deal with ranges
7768 instead of constants.
7770 While propagating ranges, we may find that two or more SSA name
7771 have equivalent, though distinct ranges. For instance,
7774 2 p_4 = ASSERT_EXPR <p_3, p_3 != 0>
7776 4 p_5 = ASSERT_EXPR <p_4, p_4 == q_2>;
7780 In the code above, pointer p_5 has range [q_2, q_2], but from the
7781 code we can also determine that p_5 cannot be NULL and, if q_2 had
7782 a non-varying range, p_5's range should also be compatible with it.
7784 These equivalences are created by two expressions: ASSERT_EXPR and
7785 copy operations. Since p_5 is an assertion on p_4, and p_4 was the
7786 result of another assertion, then we can use the fact that p_5 and
7787 p_4 are equivalent when evaluating p_5's range.
7789 Together with value ranges, we also propagate these equivalences
7790 between names so that we can take advantage of information from
7791 multiple ranges when doing final replacement. Note that this
7792 equivalency relation is transitive but not symmetric.
7794 In the example above, p_5 is equivalent to p_4, q_2 and p_3, but we
7795 cannot assert that q_2 is equivalent to p_5 because q_2 may be used
7796 in contexts where that assertion does not hold (e.g., in line 6).
7798 TODO, the main difference between this pass and Patterson's is that
7799 we do not propagate edge probabilities. We only compute whether
7800 edges can be taken or not. That is, instead of having a spectrum
7801 of jump probabilities between 0 and 1, we only deal with 0, 1 and
7802 DON'T KNOW. In the future, it may be worthwhile to propagate
7803 probabilities to aid branch prediction. */
7812 loop_optimizer_init (LOOPS_NORMAL | LOOPS_HAVE_RECORDED_EXITS);
7813 rewrite_into_loop_closed_ssa (NULL, TODO_update_ssa);
7816 insert_range_assertions ();
7818 /* Estimate number of iterations - but do not use undefined behavior
7819 for this. We can't do this lazily as other functions may compute
7820 this using undefined behavior. */
7821 free_numbers_of_iterations_estimates ();
7822 estimate_numbers_of_iterations (false);
7824 to_remove_edges = VEC_alloc (edge, heap, 10);
7825 to_update_switch_stmts = VEC_alloc (switch_update, heap, 5);
7826 threadedge_initialize_values ();
7829 ssa_propagate (vrp_visit_stmt, vrp_visit_phi_node);
7832 free_numbers_of_iterations_estimates ();
7834 /* ASSERT_EXPRs must be removed before finalizing jump threads
7835 as finalizing jump threads calls the CFG cleanup code which
7836 does not properly handle ASSERT_EXPRs. */
7837 remove_range_assertions ();
7839 /* If we exposed any new variables, go ahead and put them into
7840 SSA form now, before we handle jump threading. This simplifies
7841 interactions between rewriting of _DECL nodes into SSA form
7842 and rewriting SSA_NAME nodes into SSA form after block
7843 duplication and CFG manipulation. */
7844 update_ssa (TODO_update_ssa);
7846 finalize_jump_threads ();
7848 /* Remove dead edges from SWITCH_EXPR optimization. This leaves the
7849 CFG in a broken state and requires a cfg_cleanup run. */
7850 FOR_EACH_VEC_ELT (edge, to_remove_edges, i, e)
7852 /* Update SWITCH_EXPR case label vector. */
7853 FOR_EACH_VEC_ELT (switch_update, to_update_switch_stmts, i, su)
7856 size_t n = TREE_VEC_LENGTH (su->vec);
7858 gimple_switch_set_num_labels (su->stmt, n);
7859 for (j = 0; j < n; j++)
7860 gimple_switch_set_label (su->stmt, j, TREE_VEC_ELT (su->vec, j));
7861 /* As we may have replaced the default label with a regular one
7862 make sure to make it a real default label again. This ensures
7863 optimal expansion. */
7864 label = gimple_switch_default_label (su->stmt);
7865 CASE_LOW (label) = NULL_TREE;
7866 CASE_HIGH (label) = NULL_TREE;
7869 if (VEC_length (edge, to_remove_edges) > 0)
7870 free_dominance_info (CDI_DOMINATORS);
7872 VEC_free (edge, heap, to_remove_edges);
7873 VEC_free (switch_update, heap, to_update_switch_stmts);
7874 threadedge_finalize_values ();
7877 loop_optimizer_finalize ();
7884 return flag_tree_vrp != 0;
7887 struct gimple_opt_pass pass_vrp =
7892 gate_vrp, /* gate */
7893 execute_vrp, /* execute */
7896 0, /* static_pass_number */
7897 TV_TREE_VRP, /* tv_id */
7898 PROP_ssa, /* properties_required */
7899 0, /* properties_provided */
7900 0, /* properties_destroyed */
7901 0, /* todo_flags_start */
7906 | TODO_ggc_collect /* todo_flags_finish */