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
2218 && code != BIT_XOR_EXPR)
2220 set_value_range_to_varying (vr);
2224 /* If both ranges are UNDEFINED, so is the result. */
2225 if (vr0.type == VR_UNDEFINED && vr1.type == VR_UNDEFINED)
2227 set_value_range_to_undefined (vr);
2230 /* If one of the ranges is UNDEFINED drop it to VARYING for the following
2231 code. At some point we may want to special-case operations that
2232 have UNDEFINED result for all or some value-ranges of the not UNDEFINED
2234 else if (vr0.type == VR_UNDEFINED)
2235 set_value_range_to_varying (&vr0);
2236 else if (vr1.type == VR_UNDEFINED)
2237 set_value_range_to_varying (&vr1);
2239 /* The type of the resulting value range defaults to VR0.TYPE. */
2242 /* Refuse to operate on VARYING ranges, ranges of different kinds
2243 and symbolic ranges. As an exception, we allow BIT_AND_EXPR
2244 because we may be able to derive a useful range even if one of
2245 the operands is VR_VARYING or symbolic range. Similarly for
2246 divisions. TODO, we may be able to derive anti-ranges in
2248 if (code != BIT_AND_EXPR
2249 && code != BIT_IOR_EXPR
2250 && code != TRUNC_DIV_EXPR
2251 && code != FLOOR_DIV_EXPR
2252 && code != CEIL_DIV_EXPR
2253 && code != EXACT_DIV_EXPR
2254 && code != ROUND_DIV_EXPR
2255 && code != TRUNC_MOD_EXPR
2256 && (vr0.type == VR_VARYING
2257 || vr1.type == VR_VARYING
2258 || vr0.type != vr1.type
2259 || symbolic_range_p (&vr0)
2260 || symbolic_range_p (&vr1)))
2262 set_value_range_to_varying (vr);
2266 /* Now evaluate the expression to determine the new range. */
2267 if (POINTER_TYPE_P (expr_type))
2269 if (code == MIN_EXPR || code == MAX_EXPR)
2271 /* For MIN/MAX expressions with pointers, we only care about
2272 nullness, if both are non null, then the result is nonnull.
2273 If both are null, then the result is null. Otherwise they
2275 if (range_is_nonnull (&vr0) && range_is_nonnull (&vr1))
2276 set_value_range_to_nonnull (vr, expr_type);
2277 else if (range_is_null (&vr0) && range_is_null (&vr1))
2278 set_value_range_to_null (vr, expr_type);
2280 set_value_range_to_varying (vr);
2282 else if (code == POINTER_PLUS_EXPR)
2284 /* For pointer types, we are really only interested in asserting
2285 whether the expression evaluates to non-NULL. */
2286 if (range_is_nonnull (&vr0) || range_is_nonnull (&vr1))
2287 set_value_range_to_nonnull (vr, expr_type);
2288 else if (range_is_null (&vr0) && range_is_null (&vr1))
2289 set_value_range_to_null (vr, expr_type);
2291 set_value_range_to_varying (vr);
2293 else if (code == BIT_AND_EXPR)
2295 /* For pointer types, we are really only interested in asserting
2296 whether the expression evaluates to non-NULL. */
2297 if (range_is_nonnull (&vr0) && range_is_nonnull (&vr1))
2298 set_value_range_to_nonnull (vr, expr_type);
2299 else if (range_is_null (&vr0) || range_is_null (&vr1))
2300 set_value_range_to_null (vr, expr_type);
2302 set_value_range_to_varying (vr);
2305 set_value_range_to_varying (vr);
2310 /* For integer ranges, apply the operation to each end of the
2311 range and see what we end up with. */
2312 if (code == PLUS_EXPR
2314 || code == MAX_EXPR)
2316 /* If we have a PLUS_EXPR with two VR_ANTI_RANGEs, drop to
2317 VR_VARYING. It would take more effort to compute a precise
2318 range for such a case. For example, if we have op0 == 1 and
2319 op1 == -1 with their ranges both being ~[0,0], we would have
2320 op0 + op1 == 0, so we cannot claim that the sum is in ~[0,0].
2321 Note that we are guaranteed to have vr0.type == vr1.type at
2323 if (vr0.type == VR_ANTI_RANGE)
2325 if (code == PLUS_EXPR)
2327 set_value_range_to_varying (vr);
2330 /* For MIN_EXPR and MAX_EXPR with two VR_ANTI_RANGEs,
2331 the resulting VR_ANTI_RANGE is the same - intersection
2332 of the two ranges. */
2333 min = vrp_int_const_binop (MAX_EXPR, vr0.min, vr1.min);
2334 max = vrp_int_const_binop (MIN_EXPR, vr0.max, vr1.max);
2338 /* For operations that make the resulting range directly
2339 proportional to the original ranges, apply the operation to
2340 the same end of each range. */
2341 min = vrp_int_const_binop (code, vr0.min, vr1.min);
2342 max = vrp_int_const_binop (code, vr0.max, vr1.max);
2345 /* If both additions overflowed the range kind is still correct.
2346 This happens regularly with subtracting something in unsigned
2348 ??? See PR30318 for all the cases we do not handle. */
2349 if (code == PLUS_EXPR
2350 && (TREE_OVERFLOW (min) && !is_overflow_infinity (min))
2351 && (TREE_OVERFLOW (max) && !is_overflow_infinity (max)))
2353 min = build_int_cst_wide (TREE_TYPE (min),
2354 TREE_INT_CST_LOW (min),
2355 TREE_INT_CST_HIGH (min));
2356 max = build_int_cst_wide (TREE_TYPE (max),
2357 TREE_INT_CST_LOW (max),
2358 TREE_INT_CST_HIGH (max));
2361 else if (code == MULT_EXPR
2362 || code == TRUNC_DIV_EXPR
2363 || code == FLOOR_DIV_EXPR
2364 || code == CEIL_DIV_EXPR
2365 || code == EXACT_DIV_EXPR
2366 || code == ROUND_DIV_EXPR
2367 || code == RSHIFT_EXPR)
2373 /* If we have an unsigned MULT_EXPR with two VR_ANTI_RANGEs,
2374 drop to VR_VARYING. It would take more effort to compute a
2375 precise range for such a case. For example, if we have
2376 op0 == 65536 and op1 == 65536 with their ranges both being
2377 ~[0,0] on a 32-bit machine, we would have op0 * op1 == 0, so
2378 we cannot claim that the product is in ~[0,0]. Note that we
2379 are guaranteed to have vr0.type == vr1.type at this
2381 if (code == MULT_EXPR
2382 && vr0.type == VR_ANTI_RANGE
2383 && !TYPE_OVERFLOW_UNDEFINED (expr_type))
2385 set_value_range_to_varying (vr);
2389 /* If we have a RSHIFT_EXPR with any shift values outside [0..prec-1],
2390 then drop to VR_VARYING. Outside of this range we get undefined
2391 behavior from the shift operation. We cannot even trust
2392 SHIFT_COUNT_TRUNCATED at this stage, because that applies to rtl
2393 shifts, and the operation at the tree level may be widened. */
2394 if (code == RSHIFT_EXPR)
2396 if (vr1.type != VR_RANGE
2397 || !value_range_nonnegative_p (&vr1)
2398 || TREE_CODE (vr1.max) != INTEGER_CST
2399 || compare_tree_int (vr1.max,
2400 TYPE_PRECISION (expr_type) - 1) == 1)
2402 set_value_range_to_varying (vr);
2407 else if ((code == TRUNC_DIV_EXPR
2408 || code == FLOOR_DIV_EXPR
2409 || code == CEIL_DIV_EXPR
2410 || code == EXACT_DIV_EXPR
2411 || code == ROUND_DIV_EXPR)
2412 && (vr0.type != VR_RANGE || symbolic_range_p (&vr0)))
2414 /* For division, if op1 has VR_RANGE but op0 does not, something
2415 can be deduced just from that range. Say [min, max] / [4, max]
2416 gives [min / 4, max / 4] range. */
2417 if (vr1.type == VR_RANGE
2418 && !symbolic_range_p (&vr1)
2419 && !range_includes_zero_p (&vr1))
2421 vr0.type = type = VR_RANGE;
2422 vr0.min = vrp_val_min (expr_type);
2423 vr0.max = vrp_val_max (expr_type);
2427 set_value_range_to_varying (vr);
2432 /* For divisions, if flag_non_call_exceptions is true, we must
2433 not eliminate a division by zero. */
2434 if ((code == TRUNC_DIV_EXPR
2435 || code == FLOOR_DIV_EXPR
2436 || code == CEIL_DIV_EXPR
2437 || code == EXACT_DIV_EXPR
2438 || code == ROUND_DIV_EXPR)
2439 && cfun->can_throw_non_call_exceptions
2440 && (vr1.type != VR_RANGE
2441 || symbolic_range_p (&vr1)
2442 || range_includes_zero_p (&vr1)))
2444 set_value_range_to_varying (vr);
2448 /* For divisions, if op0 is VR_RANGE, we can deduce a range
2449 even if op1 is VR_VARYING, VR_ANTI_RANGE, symbolic or can
2451 if ((code == TRUNC_DIV_EXPR
2452 || code == FLOOR_DIV_EXPR
2453 || code == CEIL_DIV_EXPR
2454 || code == EXACT_DIV_EXPR
2455 || code == ROUND_DIV_EXPR)
2456 && vr0.type == VR_RANGE
2457 && (vr1.type != VR_RANGE
2458 || symbolic_range_p (&vr1)
2459 || range_includes_zero_p (&vr1)))
2461 tree zero = build_int_cst (TREE_TYPE (vr0.min), 0);
2467 if (TYPE_UNSIGNED (expr_type)
2468 || value_range_nonnegative_p (&vr1))
2470 /* For unsigned division or when divisor is known
2471 to be non-negative, the range has to cover
2472 all numbers from 0 to max for positive max
2473 and all numbers from min to 0 for negative min. */
2474 cmp = compare_values (vr0.max, zero);
2477 else if (cmp == 0 || cmp == 1)
2481 cmp = compare_values (vr0.min, zero);
2484 else if (cmp == 0 || cmp == -1)
2491 /* Otherwise the range is -max .. max or min .. -min
2492 depending on which bound is bigger in absolute value,
2493 as the division can change the sign. */
2494 abs_extent_range (vr, vr0.min, vr0.max);
2497 if (type == VR_VARYING)
2499 set_value_range_to_varying (vr);
2504 /* Multiplications and divisions are a bit tricky to handle,
2505 depending on the mix of signs we have in the two ranges, we
2506 need to operate on different values to get the minimum and
2507 maximum values for the new range. One approach is to figure
2508 out all the variations of range combinations and do the
2511 However, this involves several calls to compare_values and it
2512 is pretty convoluted. It's simpler to do the 4 operations
2513 (MIN0 OP MIN1, MIN0 OP MAX1, MAX0 OP MIN1 and MAX0 OP MAX0 OP
2514 MAX1) and then figure the smallest and largest values to form
2518 gcc_assert ((vr0.type == VR_RANGE
2519 || (code == MULT_EXPR && vr0.type == VR_ANTI_RANGE))
2520 && vr0.type == vr1.type);
2522 /* Compute the 4 cross operations. */
2524 val[0] = vrp_int_const_binop (code, vr0.min, vr1.min);
2525 if (val[0] == NULL_TREE)
2528 if (vr1.max == vr1.min)
2532 val[1] = vrp_int_const_binop (code, vr0.min, vr1.max);
2533 if (val[1] == NULL_TREE)
2537 if (vr0.max == vr0.min)
2541 val[2] = vrp_int_const_binop (code, vr0.max, vr1.min);
2542 if (val[2] == NULL_TREE)
2546 if (vr0.min == vr0.max || vr1.min == vr1.max)
2550 val[3] = vrp_int_const_binop (code, vr0.max, vr1.max);
2551 if (val[3] == NULL_TREE)
2557 set_value_range_to_varying (vr);
2561 /* Set MIN to the minimum of VAL[i] and MAX to the maximum
2565 for (i = 1; i < 4; i++)
2567 if (!is_gimple_min_invariant (min)
2568 || (TREE_OVERFLOW (min) && !is_overflow_infinity (min))
2569 || !is_gimple_min_invariant (max)
2570 || (TREE_OVERFLOW (max) && !is_overflow_infinity (max)))
2575 if (!is_gimple_min_invariant (val[i])
2576 || (TREE_OVERFLOW (val[i])
2577 && !is_overflow_infinity (val[i])))
2579 /* If we found an overflowed value, set MIN and MAX
2580 to it so that we set the resulting range to
2586 if (compare_values (val[i], min) == -1)
2589 if (compare_values (val[i], max) == 1)
2595 else if (code == TRUNC_MOD_EXPR)
2597 if (vr1.type != VR_RANGE
2598 || symbolic_range_p (&vr1)
2599 || range_includes_zero_p (&vr1)
2600 || vrp_val_is_min (vr1.min))
2602 set_value_range_to_varying (vr);
2606 /* Compute MAX <|vr1.min|, |vr1.max|> - 1. */
2607 max = fold_unary_to_constant (ABS_EXPR, expr_type, vr1.min);
2608 if (tree_int_cst_lt (max, vr1.max))
2610 max = int_const_binop (MINUS_EXPR, max, integer_one_node);
2611 /* If the dividend is non-negative the modulus will be
2612 non-negative as well. */
2613 if (TYPE_UNSIGNED (expr_type)
2614 || value_range_nonnegative_p (&vr0))
2615 min = build_int_cst (TREE_TYPE (max), 0);
2617 min = fold_unary_to_constant (NEGATE_EXPR, expr_type, max);
2619 else if (code == MINUS_EXPR)
2621 /* If we have a MINUS_EXPR with two VR_ANTI_RANGEs, drop to
2622 VR_VARYING. It would take more effort to compute a precise
2623 range for such a case. For example, if we have op0 == 1 and
2624 op1 == 1 with their ranges both being ~[0,0], we would have
2625 op0 - op1 == 0, so we cannot claim that the difference is in
2626 ~[0,0]. Note that we are guaranteed to have
2627 vr0.type == vr1.type at this point. */
2628 if (vr0.type == VR_ANTI_RANGE)
2630 set_value_range_to_varying (vr);
2634 /* For MINUS_EXPR, apply the operation to the opposite ends of
2636 min = vrp_int_const_binop (code, vr0.min, vr1.max);
2637 max = vrp_int_const_binop (code, vr0.max, vr1.min);
2639 else if (code == BIT_AND_EXPR || code == BIT_IOR_EXPR || code == BIT_XOR_EXPR)
2641 bool int_cst_range0, int_cst_range1;
2642 double_int may_be_nonzero0, may_be_nonzero1;
2643 double_int must_be_nonzero0, must_be_nonzero1;
2645 int_cst_range0 = zero_nonzero_bits_from_vr (&vr0, &may_be_nonzero0,
2647 int_cst_range1 = zero_nonzero_bits_from_vr (&vr1, &may_be_nonzero1,
2651 if (code == BIT_AND_EXPR)
2653 min = double_int_to_tree (expr_type,
2654 double_int_and (must_be_nonzero0,
2656 max = double_int_to_tree (expr_type,
2657 double_int_and (may_be_nonzero0,
2659 if (tree_int_cst_sgn (min) < 0)
2661 if (tree_int_cst_sgn (max) < 0)
2663 if (int_cst_range0 && tree_int_cst_sgn (vr0.min) >= 0)
2665 if (min == NULL_TREE)
2666 min = build_int_cst (expr_type, 0);
2667 if (max == NULL_TREE || tree_int_cst_lt (vr0.max, max))
2670 if (int_cst_range1 && tree_int_cst_sgn (vr1.min) >= 0)
2672 if (min == NULL_TREE)
2673 min = build_int_cst (expr_type, 0);
2674 if (max == NULL_TREE || tree_int_cst_lt (vr1.max, max))
2678 else if (code == BIT_IOR_EXPR)
2680 min = double_int_to_tree (expr_type,
2681 double_int_ior (must_be_nonzero0,
2683 max = double_int_to_tree (expr_type,
2684 double_int_ior (may_be_nonzero0,
2686 if (tree_int_cst_sgn (max) < 0)
2690 if (tree_int_cst_sgn (min) < 0)
2693 min = vrp_int_const_binop (MAX_EXPR, min, vr0.min);
2696 min = vrp_int_const_binop (MAX_EXPR, min, vr1.min);
2698 else if (code == BIT_XOR_EXPR)
2700 double_int result_zero_bits, result_one_bits;
2702 = double_int_ior (double_int_and (must_be_nonzero0,
2705 (double_int_ior (may_be_nonzero0,
2708 = double_int_ior (double_int_and
2710 double_int_not (may_be_nonzero1)),
2713 double_int_not (may_be_nonzero0)));
2714 max = double_int_to_tree (expr_type,
2715 double_int_not (result_zero_bits));
2716 min = double_int_to_tree (expr_type, result_one_bits);
2717 /* Return a [min, max] range if we know the
2718 result range is either positive or negative. */
2719 if (tree_int_cst_sgn (max) >= 0)
2720 /* The range is bound by a lower value of 0. */;
2721 else if (tree_int_cst_sgn (min) < 0)
2722 /* The range is bound by an upper value of -1. */;
2724 /* We don't know whether the sign bit is set or not. */
2725 max = min = NULL_TREE;
2729 set_value_range_to_varying (vr);
2736 /* If either MIN or MAX overflowed, then set the resulting range to
2737 VARYING. But we do accept an overflow infinity
2739 if (min == NULL_TREE
2740 || !is_gimple_min_invariant (min)
2741 || (TREE_OVERFLOW (min) && !is_overflow_infinity (min))
2743 || !is_gimple_min_invariant (max)
2744 || (TREE_OVERFLOW (max) && !is_overflow_infinity (max)))
2746 set_value_range_to_varying (vr);
2752 2) [-INF, +-INF(OVF)]
2753 3) [+-INF(OVF), +INF]
2754 4) [+-INF(OVF), +-INF(OVF)]
2755 We learn nothing when we have INF and INF(OVF) on both sides.
2756 Note that we do accept [-INF, -INF] and [+INF, +INF] without
2758 if ((vrp_val_is_min (min) || is_overflow_infinity (min))
2759 && (vrp_val_is_max (max) || is_overflow_infinity (max)))
2761 set_value_range_to_varying (vr);
2765 cmp = compare_values (min, max);
2766 if (cmp == -2 || cmp == 1)
2768 /* If the new range has its limits swapped around (MIN > MAX),
2769 then the operation caused one of them to wrap around, mark
2770 the new range VARYING. */
2771 set_value_range_to_varying (vr);
2774 set_value_range (vr, type, min, max, NULL);
2777 /* Extract range information from a binary expression OP0 CODE OP1 based on
2778 the ranges of each of its operands with resulting type EXPR_TYPE.
2779 The resulting range is stored in *VR. */
2782 extract_range_from_binary_expr (value_range_t *vr,
2783 enum tree_code code,
2784 tree expr_type, tree op0, tree op1)
2786 value_range_t vr0 = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
2787 value_range_t vr1 = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
2789 /* Get value ranges for each operand. For constant operands, create
2790 a new value range with the operand to simplify processing. */
2791 if (TREE_CODE (op0) == SSA_NAME)
2792 vr0 = *(get_value_range (op0));
2793 else if (is_gimple_min_invariant (op0))
2794 set_value_range_to_value (&vr0, op0, NULL);
2796 set_value_range_to_varying (&vr0);
2798 if (TREE_CODE (op1) == SSA_NAME)
2799 vr1 = *(get_value_range (op1));
2800 else if (is_gimple_min_invariant (op1))
2801 set_value_range_to_value (&vr1, op1, NULL);
2803 set_value_range_to_varying (&vr1);
2805 extract_range_from_binary_expr_1 (vr, code, expr_type, &vr0, &vr1);
2808 /* Extract range information from a unary expression EXPR based on
2809 the range of its operand and the expression code. */
2812 extract_range_from_unary_expr (value_range_t *vr, enum tree_code code,
2813 tree type, tree op0)
2817 value_range_t vr0 = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
2819 /* Refuse to operate on certain unary expressions for which we
2820 cannot easily determine a resulting range. */
2821 if (code == FIX_TRUNC_EXPR
2822 || code == FLOAT_EXPR
2823 || code == BIT_NOT_EXPR
2824 || code == CONJ_EXPR)
2826 /* We can still do constant propagation here. */
2827 if ((op0 = op_with_constant_singleton_value_range (op0)) != NULL_TREE)
2829 tree tem = fold_unary (code, type, op0);
2831 && is_gimple_min_invariant (tem)
2832 && !is_overflow_infinity (tem))
2834 set_value_range (vr, VR_RANGE, tem, tem, NULL);
2838 set_value_range_to_varying (vr);
2842 /* Get value ranges for the operand. For constant operands, create
2843 a new value range with the operand to simplify processing. */
2844 if (TREE_CODE (op0) == SSA_NAME)
2845 vr0 = *(get_value_range (op0));
2846 else if (is_gimple_min_invariant (op0))
2847 set_value_range_to_value (&vr0, op0, NULL);
2849 set_value_range_to_varying (&vr0);
2851 /* If VR0 is UNDEFINED, so is the result. */
2852 if (vr0.type == VR_UNDEFINED)
2854 set_value_range_to_undefined (vr);
2858 /* Refuse to operate on symbolic ranges, or if neither operand is
2859 a pointer or integral type. */
2860 if ((!INTEGRAL_TYPE_P (TREE_TYPE (op0))
2861 && !POINTER_TYPE_P (TREE_TYPE (op0)))
2862 || (vr0.type != VR_VARYING
2863 && symbolic_range_p (&vr0)))
2865 set_value_range_to_varying (vr);
2869 /* If the expression involves pointers, we are only interested in
2870 determining if it evaluates to NULL [0, 0] or non-NULL (~[0, 0]). */
2871 if (POINTER_TYPE_P (type) || POINTER_TYPE_P (TREE_TYPE (op0)))
2876 if (range_is_nonnull (&vr0)
2877 || (tree_unary_nonzero_warnv_p (code, type, op0, &sop)
2879 set_value_range_to_nonnull (vr, type);
2880 else if (range_is_null (&vr0))
2881 set_value_range_to_null (vr, type);
2883 set_value_range_to_varying (vr);
2888 /* Handle unary expressions on integer ranges. */
2889 if (CONVERT_EXPR_CODE_P (code)
2890 && INTEGRAL_TYPE_P (type)
2891 && INTEGRAL_TYPE_P (TREE_TYPE (op0)))
2893 tree inner_type = TREE_TYPE (op0);
2894 tree outer_type = type;
2896 /* If VR0 is varying and we increase the type precision, assume
2897 a full range for the following transformation. */
2898 if (vr0.type == VR_VARYING
2899 && TYPE_PRECISION (inner_type) < TYPE_PRECISION (outer_type))
2901 vr0.type = VR_RANGE;
2902 vr0.min = TYPE_MIN_VALUE (inner_type);
2903 vr0.max = TYPE_MAX_VALUE (inner_type);
2906 /* If VR0 is a constant range or anti-range and the conversion is
2907 not truncating we can convert the min and max values and
2908 canonicalize the resulting range. Otherwise we can do the
2909 conversion if the size of the range is less than what the
2910 precision of the target type can represent and the range is
2911 not an anti-range. */
2912 if ((vr0.type == VR_RANGE
2913 || vr0.type == VR_ANTI_RANGE)
2914 && TREE_CODE (vr0.min) == INTEGER_CST
2915 && TREE_CODE (vr0.max) == INTEGER_CST
2916 && (!is_overflow_infinity (vr0.min)
2917 || (vr0.type == VR_RANGE
2918 && TYPE_PRECISION (outer_type) > TYPE_PRECISION (inner_type)
2919 && needs_overflow_infinity (outer_type)
2920 && supports_overflow_infinity (outer_type)))
2921 && (!is_overflow_infinity (vr0.max)
2922 || (vr0.type == VR_RANGE
2923 && TYPE_PRECISION (outer_type) > TYPE_PRECISION (inner_type)
2924 && needs_overflow_infinity (outer_type)
2925 && supports_overflow_infinity (outer_type)))
2926 && (TYPE_PRECISION (outer_type) >= TYPE_PRECISION (inner_type)
2927 || (vr0.type == VR_RANGE
2928 && integer_zerop (int_const_binop (RSHIFT_EXPR,
2929 int_const_binop (MINUS_EXPR, vr0.max, vr0.min),
2930 size_int (TYPE_PRECISION (outer_type)))))))
2932 tree new_min, new_max;
2933 new_min = force_fit_type_double (outer_type,
2934 tree_to_double_int (vr0.min),
2936 new_max = force_fit_type_double (outer_type,
2937 tree_to_double_int (vr0.max),
2939 if (is_overflow_infinity (vr0.min))
2940 new_min = negative_overflow_infinity (outer_type);
2941 if (is_overflow_infinity (vr0.max))
2942 new_max = positive_overflow_infinity (outer_type);
2943 set_and_canonicalize_value_range (vr, vr0.type,
2944 new_min, new_max, NULL);
2948 set_value_range_to_varying (vr);
2952 /* Conversion of a VR_VARYING value to a wider type can result
2953 in a usable range. So wait until after we've handled conversions
2954 before dropping the result to VR_VARYING if we had a source
2955 operand that is VR_VARYING. */
2956 if (vr0.type == VR_VARYING)
2958 set_value_range_to_varying (vr);
2962 /* Apply the operation to each end of the range and see what we end
2964 if (code == NEGATE_EXPR
2965 && !TYPE_UNSIGNED (type))
2967 /* NEGATE_EXPR flips the range around. We need to treat
2968 TYPE_MIN_VALUE specially. */
2969 if (is_positive_overflow_infinity (vr0.max))
2970 min = negative_overflow_infinity (type);
2971 else if (is_negative_overflow_infinity (vr0.max))
2972 min = positive_overflow_infinity (type);
2973 else if (!vrp_val_is_min (vr0.max))
2974 min = fold_unary_to_constant (code, type, vr0.max);
2975 else if (needs_overflow_infinity (type))
2977 if (supports_overflow_infinity (type)
2978 && !is_overflow_infinity (vr0.min)
2979 && !vrp_val_is_min (vr0.min))
2980 min = positive_overflow_infinity (type);
2983 set_value_range_to_varying (vr);
2988 min = TYPE_MIN_VALUE (type);
2990 if (is_positive_overflow_infinity (vr0.min))
2991 max = negative_overflow_infinity (type);
2992 else if (is_negative_overflow_infinity (vr0.min))
2993 max = positive_overflow_infinity (type);
2994 else if (!vrp_val_is_min (vr0.min))
2995 max = fold_unary_to_constant (code, type, vr0.min);
2996 else if (needs_overflow_infinity (type))
2998 if (supports_overflow_infinity (type))
2999 max = positive_overflow_infinity (type);
3002 set_value_range_to_varying (vr);
3007 max = TYPE_MIN_VALUE (type);
3009 else if (code == NEGATE_EXPR
3010 && TYPE_UNSIGNED (type))
3012 if (!range_includes_zero_p (&vr0))
3014 max = fold_unary_to_constant (code, type, vr0.min);
3015 min = fold_unary_to_constant (code, type, vr0.max);
3019 if (range_is_null (&vr0))
3020 set_value_range_to_null (vr, type);
3022 set_value_range_to_varying (vr);
3026 else if (code == ABS_EXPR
3027 && !TYPE_UNSIGNED (type))
3029 /* -TYPE_MIN_VALUE = TYPE_MIN_VALUE with flag_wrapv so we can't get a
3031 if (!TYPE_OVERFLOW_UNDEFINED (type)
3032 && ((vr0.type == VR_RANGE
3033 && vrp_val_is_min (vr0.min))
3034 || (vr0.type == VR_ANTI_RANGE
3035 && !vrp_val_is_min (vr0.min)
3036 && !range_includes_zero_p (&vr0))))
3038 set_value_range_to_varying (vr);
3042 /* ABS_EXPR may flip the range around, if the original range
3043 included negative values. */
3044 if (is_overflow_infinity (vr0.min))
3045 min = positive_overflow_infinity (type);
3046 else if (!vrp_val_is_min (vr0.min))
3047 min = fold_unary_to_constant (code, type, vr0.min);
3048 else if (!needs_overflow_infinity (type))
3049 min = TYPE_MAX_VALUE (type);
3050 else if (supports_overflow_infinity (type))
3051 min = positive_overflow_infinity (type);
3054 set_value_range_to_varying (vr);
3058 if (is_overflow_infinity (vr0.max))
3059 max = positive_overflow_infinity (type);
3060 else if (!vrp_val_is_min (vr0.max))
3061 max = fold_unary_to_constant (code, type, vr0.max);
3062 else if (!needs_overflow_infinity (type))
3063 max = TYPE_MAX_VALUE (type);
3064 else if (supports_overflow_infinity (type)
3065 /* We shouldn't generate [+INF, +INF] as set_value_range
3066 doesn't like this and ICEs. */
3067 && !is_positive_overflow_infinity (min))
3068 max = positive_overflow_infinity (type);
3071 set_value_range_to_varying (vr);
3075 cmp = compare_values (min, max);
3077 /* If a VR_ANTI_RANGEs contains zero, then we have
3078 ~[-INF, min(MIN, MAX)]. */
3079 if (vr0.type == VR_ANTI_RANGE)
3081 if (range_includes_zero_p (&vr0))
3083 /* Take the lower of the two values. */
3087 /* Create ~[-INF, min (abs(MIN), abs(MAX))]
3088 or ~[-INF + 1, min (abs(MIN), abs(MAX))] when
3089 flag_wrapv is set and the original anti-range doesn't include
3090 TYPE_MIN_VALUE, remember -TYPE_MIN_VALUE = TYPE_MIN_VALUE. */
3091 if (TYPE_OVERFLOW_WRAPS (type))
3093 tree type_min_value = TYPE_MIN_VALUE (type);
3095 min = (vr0.min != type_min_value
3096 ? int_const_binop (PLUS_EXPR, type_min_value,
3102 if (overflow_infinity_range_p (&vr0))
3103 min = negative_overflow_infinity (type);
3105 min = TYPE_MIN_VALUE (type);
3110 /* All else has failed, so create the range [0, INF], even for
3111 flag_wrapv since TYPE_MIN_VALUE is in the original
3113 vr0.type = VR_RANGE;
3114 min = build_int_cst (type, 0);
3115 if (needs_overflow_infinity (type))
3117 if (supports_overflow_infinity (type))
3118 max = positive_overflow_infinity (type);
3121 set_value_range_to_varying (vr);
3126 max = TYPE_MAX_VALUE (type);
3130 /* If the range contains zero then we know that the minimum value in the
3131 range will be zero. */
3132 else if (range_includes_zero_p (&vr0))
3136 min = build_int_cst (type, 0);
3140 /* If the range was reversed, swap MIN and MAX. */
3151 /* Otherwise, operate on each end of the range. */
3152 min = fold_unary_to_constant (code, type, vr0.min);
3153 max = fold_unary_to_constant (code, type, vr0.max);
3155 if (needs_overflow_infinity (type))
3157 gcc_assert (code != NEGATE_EXPR && code != ABS_EXPR);
3159 /* If both sides have overflowed, we don't know
3161 if ((is_overflow_infinity (vr0.min)
3162 || TREE_OVERFLOW (min))
3163 && (is_overflow_infinity (vr0.max)
3164 || TREE_OVERFLOW (max)))
3166 set_value_range_to_varying (vr);
3170 if (is_overflow_infinity (vr0.min))
3172 else if (TREE_OVERFLOW (min))
3174 if (supports_overflow_infinity (type))
3175 min = (tree_int_cst_sgn (min) >= 0
3176 ? positive_overflow_infinity (TREE_TYPE (min))
3177 : negative_overflow_infinity (TREE_TYPE (min)));
3180 set_value_range_to_varying (vr);
3185 if (is_overflow_infinity (vr0.max))
3187 else if (TREE_OVERFLOW (max))
3189 if (supports_overflow_infinity (type))
3190 max = (tree_int_cst_sgn (max) >= 0
3191 ? positive_overflow_infinity (TREE_TYPE (max))
3192 : negative_overflow_infinity (TREE_TYPE (max)));
3195 set_value_range_to_varying (vr);
3202 cmp = compare_values (min, max);
3203 if (cmp == -2 || cmp == 1)
3205 /* If the new range has its limits swapped around (MIN > MAX),
3206 then the operation caused one of them to wrap around, mark
3207 the new range VARYING. */
3208 set_value_range_to_varying (vr);
3211 set_value_range (vr, vr0.type, min, max, NULL);
3215 /* Extract range information from a conditional expression EXPR based on
3216 the ranges of each of its operands and the expression code. */
3219 extract_range_from_cond_expr (value_range_t *vr, tree expr)
3222 value_range_t vr0 = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
3223 value_range_t vr1 = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
3225 /* Get value ranges for each operand. For constant operands, create
3226 a new value range with the operand to simplify processing. */
3227 op0 = COND_EXPR_THEN (expr);
3228 if (TREE_CODE (op0) == SSA_NAME)
3229 vr0 = *(get_value_range (op0));
3230 else if (is_gimple_min_invariant (op0))
3231 set_value_range_to_value (&vr0, op0, NULL);
3233 set_value_range_to_varying (&vr0);
3235 op1 = COND_EXPR_ELSE (expr);
3236 if (TREE_CODE (op1) == SSA_NAME)
3237 vr1 = *(get_value_range (op1));
3238 else if (is_gimple_min_invariant (op1))
3239 set_value_range_to_value (&vr1, op1, NULL);
3241 set_value_range_to_varying (&vr1);
3243 /* The resulting value range is the union of the operand ranges */
3244 vrp_meet (&vr0, &vr1);
3245 copy_value_range (vr, &vr0);
3249 /* Extract range information from a comparison expression EXPR based
3250 on the range of its operand and the expression code. */
3253 extract_range_from_comparison (value_range_t *vr, enum tree_code code,
3254 tree type, tree op0, tree op1)
3259 val = vrp_evaluate_conditional_warnv_with_ops (code, op0, op1, false, &sop,
3262 /* A disadvantage of using a special infinity as an overflow
3263 representation is that we lose the ability to record overflow
3264 when we don't have an infinity. So we have to ignore a result
3265 which relies on overflow. */
3267 if (val && !is_overflow_infinity (val) && !sop)
3269 /* Since this expression was found on the RHS of an assignment,
3270 its type may be different from _Bool. Convert VAL to EXPR's
3272 val = fold_convert (type, val);
3273 if (is_gimple_min_invariant (val))
3274 set_value_range_to_value (vr, val, vr->equiv);
3276 set_value_range (vr, VR_RANGE, val, val, vr->equiv);
3279 /* The result of a comparison is always true or false. */
3280 set_value_range_to_truthvalue (vr, type);
3283 /* Try to derive a nonnegative or nonzero range out of STMT relying
3284 primarily on generic routines in fold in conjunction with range data.
3285 Store the result in *VR */
3288 extract_range_basic (value_range_t *vr, gimple stmt)
3291 tree type = gimple_expr_type (stmt);
3293 if (INTEGRAL_TYPE_P (type)
3294 && gimple_stmt_nonnegative_warnv_p (stmt, &sop))
3295 set_value_range_to_nonnegative (vr, type,
3296 sop || stmt_overflow_infinity (stmt));
3297 else if (vrp_stmt_computes_nonzero (stmt, &sop)
3299 set_value_range_to_nonnull (vr, type);
3301 set_value_range_to_varying (vr);
3305 /* Try to compute a useful range out of assignment STMT and store it
3309 extract_range_from_assignment (value_range_t *vr, gimple stmt)
3311 enum tree_code code = gimple_assign_rhs_code (stmt);
3313 if (code == ASSERT_EXPR)
3314 extract_range_from_assert (vr, gimple_assign_rhs1 (stmt));
3315 else if (code == SSA_NAME)
3316 extract_range_from_ssa_name (vr, gimple_assign_rhs1 (stmt));
3317 else if (TREE_CODE_CLASS (code) == tcc_binary)
3318 extract_range_from_binary_expr (vr, gimple_assign_rhs_code (stmt),
3319 gimple_expr_type (stmt),
3320 gimple_assign_rhs1 (stmt),
3321 gimple_assign_rhs2 (stmt));
3322 else if (TREE_CODE_CLASS (code) == tcc_unary)
3323 extract_range_from_unary_expr (vr, gimple_assign_rhs_code (stmt),
3324 gimple_expr_type (stmt),
3325 gimple_assign_rhs1 (stmt));
3326 else if (code == COND_EXPR)
3327 extract_range_from_cond_expr (vr, gimple_assign_rhs1 (stmt));
3328 else if (TREE_CODE_CLASS (code) == tcc_comparison)
3329 extract_range_from_comparison (vr, gimple_assign_rhs_code (stmt),
3330 gimple_expr_type (stmt),
3331 gimple_assign_rhs1 (stmt),
3332 gimple_assign_rhs2 (stmt));
3333 else if (get_gimple_rhs_class (code) == GIMPLE_SINGLE_RHS
3334 && is_gimple_min_invariant (gimple_assign_rhs1 (stmt)))
3335 set_value_range_to_value (vr, gimple_assign_rhs1 (stmt), NULL);
3337 set_value_range_to_varying (vr);
3339 if (vr->type == VR_VARYING)
3340 extract_range_basic (vr, stmt);
3343 /* Given a range VR, a LOOP and a variable VAR, determine whether it
3344 would be profitable to adjust VR using scalar evolution information
3345 for VAR. If so, update VR with the new limits. */
3348 adjust_range_with_scev (value_range_t *vr, struct loop *loop,
3349 gimple stmt, tree var)
3351 tree init, step, chrec, tmin, tmax, min, max, type, tem;
3352 enum ev_direction dir;
3354 /* TODO. Don't adjust anti-ranges. An anti-range may provide
3355 better opportunities than a regular range, but I'm not sure. */
3356 if (vr->type == VR_ANTI_RANGE)
3359 chrec = instantiate_parameters (loop, analyze_scalar_evolution (loop, var));
3361 /* Like in PR19590, scev can return a constant function. */
3362 if (is_gimple_min_invariant (chrec))
3364 set_value_range_to_value (vr, chrec, vr->equiv);
3368 if (TREE_CODE (chrec) != POLYNOMIAL_CHREC)
3371 init = initial_condition_in_loop_num (chrec, loop->num);
3372 tem = op_with_constant_singleton_value_range (init);
3375 step = evolution_part_in_loop_num (chrec, loop->num);
3376 tem = op_with_constant_singleton_value_range (step);
3380 /* If STEP is symbolic, we can't know whether INIT will be the
3381 minimum or maximum value in the range. Also, unless INIT is
3382 a simple expression, compare_values and possibly other functions
3383 in tree-vrp won't be able to handle it. */
3384 if (step == NULL_TREE
3385 || !is_gimple_min_invariant (step)
3386 || !valid_value_p (init))
3389 dir = scev_direction (chrec);
3390 if (/* Do not adjust ranges if we do not know whether the iv increases
3391 or decreases, ... */
3392 dir == EV_DIR_UNKNOWN
3393 /* ... or if it may wrap. */
3394 || scev_probably_wraps_p (init, step, stmt, get_chrec_loop (chrec),
3398 /* We use TYPE_MIN_VALUE and TYPE_MAX_VALUE here instead of
3399 negative_overflow_infinity and positive_overflow_infinity,
3400 because we have concluded that the loop probably does not
3403 type = TREE_TYPE (var);
3404 if (POINTER_TYPE_P (type) || !TYPE_MIN_VALUE (type))
3405 tmin = lower_bound_in_type (type, type);
3407 tmin = TYPE_MIN_VALUE (type);
3408 if (POINTER_TYPE_P (type) || !TYPE_MAX_VALUE (type))
3409 tmax = upper_bound_in_type (type, type);
3411 tmax = TYPE_MAX_VALUE (type);
3413 /* Try to use estimated number of iterations for the loop to constrain the
3414 final value in the evolution. */
3415 if (TREE_CODE (step) == INTEGER_CST
3416 && is_gimple_val (init)
3417 && (TREE_CODE (init) != SSA_NAME
3418 || get_value_range (init)->type == VR_RANGE))
3422 if (estimated_loop_iterations (loop, true, &nit))
3424 value_range_t maxvr = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
3426 bool unsigned_p = TYPE_UNSIGNED (TREE_TYPE (step));
3429 dtmp = double_int_mul_with_sign (tree_to_double_int (step), nit,
3430 unsigned_p, &overflow);
3431 /* If the multiplication overflowed we can't do a meaningful
3432 adjustment. Likewise if the result doesn't fit in the type
3433 of the induction variable. For a signed type we have to
3434 check whether the result has the expected signedness which
3435 is that of the step as number of iterations is unsigned. */
3437 && double_int_fits_to_tree_p (TREE_TYPE (init), dtmp)
3439 || ((dtmp.high ^ TREE_INT_CST_HIGH (step)) >= 0)))
3441 tem = double_int_to_tree (TREE_TYPE (init), dtmp);
3442 extract_range_from_binary_expr (&maxvr, PLUS_EXPR,
3443 TREE_TYPE (init), init, tem);
3444 /* Likewise if the addition did. */
3445 if (maxvr.type == VR_RANGE)
3454 if (vr->type == VR_VARYING || vr->type == VR_UNDEFINED)
3459 /* For VARYING or UNDEFINED ranges, just about anything we get
3460 from scalar evolutions should be better. */
3462 if (dir == EV_DIR_DECREASES)
3467 /* If we would create an invalid range, then just assume we
3468 know absolutely nothing. This may be over-conservative,
3469 but it's clearly safe, and should happen only in unreachable
3470 parts of code, or for invalid programs. */
3471 if (compare_values (min, max) == 1)
3474 set_value_range (vr, VR_RANGE, min, max, vr->equiv);
3476 else if (vr->type == VR_RANGE)
3481 if (dir == EV_DIR_DECREASES)
3483 /* INIT is the maximum value. If INIT is lower than VR->MAX
3484 but no smaller than VR->MIN, set VR->MAX to INIT. */
3485 if (compare_values (init, max) == -1)
3488 /* According to the loop information, the variable does not
3489 overflow. If we think it does, probably because of an
3490 overflow due to arithmetic on a different INF value,
3492 if (is_negative_overflow_infinity (min)
3493 || compare_values (min, tmin) == -1)
3499 /* If INIT is bigger than VR->MIN, set VR->MIN to INIT. */
3500 if (compare_values (init, min) == 1)
3503 if (is_positive_overflow_infinity (max)
3504 || compare_values (tmax, max) == -1)
3508 /* If we just created an invalid range with the minimum
3509 greater than the maximum, we fail conservatively.
3510 This should happen only in unreachable
3511 parts of code, or for invalid programs. */
3512 if (compare_values (min, max) == 1)
3515 set_value_range (vr, VR_RANGE, min, max, vr->equiv);
3519 /* Return true if VAR may overflow at STMT. This checks any available
3520 loop information to see if we can determine that VAR does not
3524 vrp_var_may_overflow (tree var, gimple stmt)
3527 tree chrec, init, step;
3529 if (current_loops == NULL)
3532 l = loop_containing_stmt (stmt);
3537 chrec = instantiate_parameters (l, analyze_scalar_evolution (l, var));
3538 if (TREE_CODE (chrec) != POLYNOMIAL_CHREC)
3541 init = initial_condition_in_loop_num (chrec, l->num);
3542 step = evolution_part_in_loop_num (chrec, l->num);
3544 if (step == NULL_TREE
3545 || !is_gimple_min_invariant (step)
3546 || !valid_value_p (init))
3549 /* If we get here, we know something useful about VAR based on the
3550 loop information. If it wraps, it may overflow. */
3552 if (scev_probably_wraps_p (init, step, stmt, get_chrec_loop (chrec),
3556 if (dump_file && (dump_flags & TDF_DETAILS) != 0)
3558 print_generic_expr (dump_file, var, 0);
3559 fprintf (dump_file, ": loop information indicates does not overflow\n");
3566 /* Given two numeric value ranges VR0, VR1 and a comparison code COMP:
3568 - Return BOOLEAN_TRUE_NODE if VR0 COMP VR1 always returns true for
3569 all the values in the ranges.
3571 - Return BOOLEAN_FALSE_NODE if the comparison always returns false.
3573 - Return NULL_TREE if it is not always possible to determine the
3574 value of the comparison.
3576 Also set *STRICT_OVERFLOW_P to indicate whether a range with an
3577 overflow infinity was used in the test. */
3581 compare_ranges (enum tree_code comp, value_range_t *vr0, value_range_t *vr1,
3582 bool *strict_overflow_p)
3584 /* VARYING or UNDEFINED ranges cannot be compared. */
3585 if (vr0->type == VR_VARYING
3586 || vr0->type == VR_UNDEFINED
3587 || vr1->type == VR_VARYING
3588 || vr1->type == VR_UNDEFINED)
3591 /* Anti-ranges need to be handled separately. */
3592 if (vr0->type == VR_ANTI_RANGE || vr1->type == VR_ANTI_RANGE)
3594 /* If both are anti-ranges, then we cannot compute any
3596 if (vr0->type == VR_ANTI_RANGE && vr1->type == VR_ANTI_RANGE)
3599 /* These comparisons are never statically computable. */
3606 /* Equality can be computed only between a range and an
3607 anti-range. ~[VAL1, VAL2] == [VAL1, VAL2] is always false. */
3608 if (vr0->type == VR_RANGE)
3610 /* To simplify processing, make VR0 the anti-range. */
3611 value_range_t *tmp = vr0;
3616 gcc_assert (comp == NE_EXPR || comp == EQ_EXPR);
3618 if (compare_values_warnv (vr0->min, vr1->min, strict_overflow_p) == 0
3619 && compare_values_warnv (vr0->max, vr1->max, strict_overflow_p) == 0)
3620 return (comp == NE_EXPR) ? boolean_true_node : boolean_false_node;
3625 if (!usable_range_p (vr0, strict_overflow_p)
3626 || !usable_range_p (vr1, strict_overflow_p))
3629 /* Simplify processing. If COMP is GT_EXPR or GE_EXPR, switch the
3630 operands around and change the comparison code. */
3631 if (comp == GT_EXPR || comp == GE_EXPR)
3634 comp = (comp == GT_EXPR) ? LT_EXPR : LE_EXPR;
3640 if (comp == EQ_EXPR)
3642 /* Equality may only be computed if both ranges represent
3643 exactly one value. */
3644 if (compare_values_warnv (vr0->min, vr0->max, strict_overflow_p) == 0
3645 && compare_values_warnv (vr1->min, vr1->max, strict_overflow_p) == 0)
3647 int cmp_min = compare_values_warnv (vr0->min, vr1->min,
3649 int cmp_max = compare_values_warnv (vr0->max, vr1->max,
3651 if (cmp_min == 0 && cmp_max == 0)
3652 return boolean_true_node;
3653 else if (cmp_min != -2 && cmp_max != -2)
3654 return boolean_false_node;
3656 /* If [V0_MIN, V1_MAX] < [V1_MIN, V1_MAX] then V0 != V1. */
3657 else if (compare_values_warnv (vr0->min, vr1->max,
3658 strict_overflow_p) == 1
3659 || compare_values_warnv (vr1->min, vr0->max,
3660 strict_overflow_p) == 1)
3661 return boolean_false_node;
3665 else if (comp == NE_EXPR)
3669 /* If VR0 is completely to the left or completely to the right
3670 of VR1, they are always different. Notice that we need to
3671 make sure that both comparisons yield similar results to
3672 avoid comparing values that cannot be compared at
3674 cmp1 = compare_values_warnv (vr0->max, vr1->min, strict_overflow_p);
3675 cmp2 = compare_values_warnv (vr0->min, vr1->max, strict_overflow_p);
3676 if ((cmp1 == -1 && cmp2 == -1) || (cmp1 == 1 && cmp2 == 1))
3677 return boolean_true_node;
3679 /* If VR0 and VR1 represent a single value and are identical,
3681 else if (compare_values_warnv (vr0->min, vr0->max,
3682 strict_overflow_p) == 0
3683 && compare_values_warnv (vr1->min, vr1->max,
3684 strict_overflow_p) == 0
3685 && compare_values_warnv (vr0->min, vr1->min,
3686 strict_overflow_p) == 0
3687 && compare_values_warnv (vr0->max, vr1->max,
3688 strict_overflow_p) == 0)
3689 return boolean_false_node;
3691 /* Otherwise, they may or may not be different. */
3695 else if (comp == LT_EXPR || comp == LE_EXPR)
3699 /* If VR0 is to the left of VR1, return true. */
3700 tst = compare_values_warnv (vr0->max, vr1->min, strict_overflow_p);
3701 if ((comp == LT_EXPR && tst == -1)
3702 || (comp == LE_EXPR && (tst == -1 || tst == 0)))
3704 if (overflow_infinity_range_p (vr0)
3705 || overflow_infinity_range_p (vr1))
3706 *strict_overflow_p = true;
3707 return boolean_true_node;
3710 /* If VR0 is to the right of VR1, return false. */
3711 tst = compare_values_warnv (vr0->min, vr1->max, strict_overflow_p);
3712 if ((comp == LT_EXPR && (tst == 0 || tst == 1))
3713 || (comp == LE_EXPR && tst == 1))
3715 if (overflow_infinity_range_p (vr0)
3716 || overflow_infinity_range_p (vr1))
3717 *strict_overflow_p = true;
3718 return boolean_false_node;
3721 /* Otherwise, we don't know. */
3729 /* Given a value range VR, a value VAL and a comparison code COMP, return
3730 BOOLEAN_TRUE_NODE if VR COMP VAL always returns true for all the
3731 values in VR. Return BOOLEAN_FALSE_NODE if the comparison
3732 always returns false. Return NULL_TREE if it is not always
3733 possible to determine the value of the comparison. Also set
3734 *STRICT_OVERFLOW_P to indicate whether a range with an overflow
3735 infinity was used in the test. */
3738 compare_range_with_value (enum tree_code comp, value_range_t *vr, tree val,
3739 bool *strict_overflow_p)
3741 if (vr->type == VR_VARYING || vr->type == VR_UNDEFINED)
3744 /* Anti-ranges need to be handled separately. */
3745 if (vr->type == VR_ANTI_RANGE)
3747 /* For anti-ranges, the only predicates that we can compute at
3748 compile time are equality and inequality. */
3755 /* ~[VAL_1, VAL_2] OP VAL is known if VAL_1 <= VAL <= VAL_2. */
3756 if (value_inside_range (val, vr) == 1)
3757 return (comp == NE_EXPR) ? boolean_true_node : boolean_false_node;
3762 if (!usable_range_p (vr, strict_overflow_p))
3765 if (comp == EQ_EXPR)
3767 /* EQ_EXPR may only be computed if VR represents exactly
3769 if (compare_values_warnv (vr->min, vr->max, strict_overflow_p) == 0)
3771 int cmp = compare_values_warnv (vr->min, val, strict_overflow_p);
3773 return boolean_true_node;
3774 else if (cmp == -1 || cmp == 1 || cmp == 2)
3775 return boolean_false_node;
3777 else if (compare_values_warnv (val, vr->min, strict_overflow_p) == -1
3778 || compare_values_warnv (vr->max, val, strict_overflow_p) == -1)
3779 return boolean_false_node;
3783 else if (comp == NE_EXPR)
3785 /* If VAL is not inside VR, then they are always different. */
3786 if (compare_values_warnv (vr->max, val, strict_overflow_p) == -1
3787 || compare_values_warnv (vr->min, val, strict_overflow_p) == 1)
3788 return boolean_true_node;
3790 /* If VR represents exactly one value equal to VAL, then return
3792 if (compare_values_warnv (vr->min, vr->max, strict_overflow_p) == 0
3793 && compare_values_warnv (vr->min, val, strict_overflow_p) == 0)
3794 return boolean_false_node;
3796 /* Otherwise, they may or may not be different. */
3799 else if (comp == LT_EXPR || comp == LE_EXPR)
3803 /* If VR is to the left of VAL, return true. */
3804 tst = compare_values_warnv (vr->max, val, strict_overflow_p);
3805 if ((comp == LT_EXPR && tst == -1)
3806 || (comp == LE_EXPR && (tst == -1 || tst == 0)))
3808 if (overflow_infinity_range_p (vr))
3809 *strict_overflow_p = true;
3810 return boolean_true_node;
3813 /* If VR is to the right of VAL, return false. */
3814 tst = compare_values_warnv (vr->min, val, strict_overflow_p);
3815 if ((comp == LT_EXPR && (tst == 0 || tst == 1))
3816 || (comp == LE_EXPR && tst == 1))
3818 if (overflow_infinity_range_p (vr))
3819 *strict_overflow_p = true;
3820 return boolean_false_node;
3823 /* Otherwise, we don't know. */
3826 else if (comp == GT_EXPR || comp == GE_EXPR)
3830 /* If VR is to the right of VAL, return true. */
3831 tst = compare_values_warnv (vr->min, val, strict_overflow_p);
3832 if ((comp == GT_EXPR && tst == 1)
3833 || (comp == GE_EXPR && (tst == 0 || tst == 1)))
3835 if (overflow_infinity_range_p (vr))
3836 *strict_overflow_p = true;
3837 return boolean_true_node;
3840 /* If VR is to the left of VAL, return false. */
3841 tst = compare_values_warnv (vr->max, val, strict_overflow_p);
3842 if ((comp == GT_EXPR && (tst == -1 || tst == 0))
3843 || (comp == GE_EXPR && tst == -1))
3845 if (overflow_infinity_range_p (vr))
3846 *strict_overflow_p = true;
3847 return boolean_false_node;
3850 /* Otherwise, we don't know. */
3858 /* Debugging dumps. */
3860 void dump_value_range (FILE *, value_range_t *);
3861 void debug_value_range (value_range_t *);
3862 void dump_all_value_ranges (FILE *);
3863 void debug_all_value_ranges (void);
3864 void dump_vr_equiv (FILE *, bitmap);
3865 void debug_vr_equiv (bitmap);
3868 /* Dump value range VR to FILE. */
3871 dump_value_range (FILE *file, value_range_t *vr)
3874 fprintf (file, "[]");
3875 else if (vr->type == VR_UNDEFINED)
3876 fprintf (file, "UNDEFINED");
3877 else if (vr->type == VR_RANGE || vr->type == VR_ANTI_RANGE)
3879 tree type = TREE_TYPE (vr->min);
3881 fprintf (file, "%s[", (vr->type == VR_ANTI_RANGE) ? "~" : "");
3883 if (is_negative_overflow_infinity (vr->min))
3884 fprintf (file, "-INF(OVF)");
3885 else if (INTEGRAL_TYPE_P (type)
3886 && !TYPE_UNSIGNED (type)
3887 && vrp_val_is_min (vr->min))
3888 fprintf (file, "-INF");
3890 print_generic_expr (file, vr->min, 0);
3892 fprintf (file, ", ");
3894 if (is_positive_overflow_infinity (vr->max))
3895 fprintf (file, "+INF(OVF)");
3896 else if (INTEGRAL_TYPE_P (type)
3897 && vrp_val_is_max (vr->max))
3898 fprintf (file, "+INF");
3900 print_generic_expr (file, vr->max, 0);
3902 fprintf (file, "]");
3909 fprintf (file, " EQUIVALENCES: { ");
3911 EXECUTE_IF_SET_IN_BITMAP (vr->equiv, 0, i, bi)
3913 print_generic_expr (file, ssa_name (i), 0);
3914 fprintf (file, " ");
3918 fprintf (file, "} (%u elements)", c);
3921 else if (vr->type == VR_VARYING)
3922 fprintf (file, "VARYING");
3924 fprintf (file, "INVALID RANGE");
3928 /* Dump value range VR to stderr. */
3931 debug_value_range (value_range_t *vr)
3933 dump_value_range (stderr, vr);
3934 fprintf (stderr, "\n");
3938 /* Dump value ranges of all SSA_NAMEs to FILE. */
3941 dump_all_value_ranges (FILE *file)
3945 for (i = 0; i < num_vr_values; i++)
3949 print_generic_expr (file, ssa_name (i), 0);
3950 fprintf (file, ": ");
3951 dump_value_range (file, vr_value[i]);
3952 fprintf (file, "\n");
3956 fprintf (file, "\n");
3960 /* Dump all value ranges to stderr. */
3963 debug_all_value_ranges (void)
3965 dump_all_value_ranges (stderr);
3969 /* Given a COND_EXPR COND of the form 'V OP W', and an SSA name V,
3970 create a new SSA name N and return the assertion assignment
3971 'V = ASSERT_EXPR <V, V OP W>'. */
3974 build_assert_expr_for (tree cond, tree v)
3979 gcc_assert (TREE_CODE (v) == SSA_NAME);
3980 n = duplicate_ssa_name (v, NULL);
3982 if (COMPARISON_CLASS_P (cond))
3984 tree a = build2 (ASSERT_EXPR, TREE_TYPE (v), v, cond);
3985 assertion = gimple_build_assign (n, a);
3987 else if (TREE_CODE (cond) == SSA_NAME)
3989 /* Given V, build the assignment N = true. */
3990 gcc_assert (v == cond);
3991 assertion = gimple_build_assign (n, boolean_true_node);
3996 SSA_NAME_DEF_STMT (n) = assertion;
3998 /* The new ASSERT_EXPR, creates a new SSA name that replaces the
3999 operand of the ASSERT_EXPR. Register the new name and the old one
4000 in the replacement table so that we can fix the SSA web after
4001 adding all the ASSERT_EXPRs. */
4002 register_new_name_mapping (n, v);
4008 /* Return false if EXPR is a predicate expression involving floating
4012 fp_predicate (gimple stmt)
4014 GIMPLE_CHECK (stmt, GIMPLE_COND);
4016 return FLOAT_TYPE_P (TREE_TYPE (gimple_cond_lhs (stmt)));
4020 /* If the range of values taken by OP can be inferred after STMT executes,
4021 return the comparison code (COMP_CODE_P) and value (VAL_P) that
4022 describes the inferred range. Return true if a range could be
4026 infer_value_range (gimple stmt, tree op, enum tree_code *comp_code_p, tree *val_p)
4029 *comp_code_p = ERROR_MARK;
4031 /* Do not attempt to infer anything in names that flow through
4033 if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (op))
4036 /* Similarly, don't infer anything from statements that may throw
4038 if (stmt_could_throw_p (stmt))
4041 /* If STMT is the last statement of a basic block with no
4042 successors, there is no point inferring anything about any of its
4043 operands. We would not be able to find a proper insertion point
4044 for the assertion, anyway. */
4045 if (stmt_ends_bb_p (stmt) && EDGE_COUNT (gimple_bb (stmt)->succs) == 0)
4048 /* We can only assume that a pointer dereference will yield
4049 non-NULL if -fdelete-null-pointer-checks is enabled. */
4050 if (flag_delete_null_pointer_checks
4051 && POINTER_TYPE_P (TREE_TYPE (op))
4052 && gimple_code (stmt) != GIMPLE_ASM)
4054 unsigned num_uses, num_loads, num_stores;
4056 count_uses_and_derefs (op, stmt, &num_uses, &num_loads, &num_stores);
4057 if (num_loads + num_stores > 0)
4059 *val_p = build_int_cst (TREE_TYPE (op), 0);
4060 *comp_code_p = NE_EXPR;
4069 void dump_asserts_for (FILE *, tree);
4070 void debug_asserts_for (tree);
4071 void dump_all_asserts (FILE *);
4072 void debug_all_asserts (void);
4074 /* Dump all the registered assertions for NAME to FILE. */
4077 dump_asserts_for (FILE *file, tree name)
4081 fprintf (file, "Assertions to be inserted for ");
4082 print_generic_expr (file, name, 0);
4083 fprintf (file, "\n");
4085 loc = asserts_for[SSA_NAME_VERSION (name)];
4088 fprintf (file, "\t");
4089 print_gimple_stmt (file, gsi_stmt (loc->si), 0, 0);
4090 fprintf (file, "\n\tBB #%d", loc->bb->index);
4093 fprintf (file, "\n\tEDGE %d->%d", loc->e->src->index,
4094 loc->e->dest->index);
4095 dump_edge_info (file, loc->e, 0);
4097 fprintf (file, "\n\tPREDICATE: ");
4098 print_generic_expr (file, name, 0);
4099 fprintf (file, " %s ", tree_code_name[(int)loc->comp_code]);
4100 print_generic_expr (file, loc->val, 0);
4101 fprintf (file, "\n\n");
4105 fprintf (file, "\n");
4109 /* Dump all the registered assertions for NAME to stderr. */
4112 debug_asserts_for (tree name)
4114 dump_asserts_for (stderr, name);
4118 /* Dump all the registered assertions for all the names to FILE. */
4121 dump_all_asserts (FILE *file)
4126 fprintf (file, "\nASSERT_EXPRs to be inserted\n\n");
4127 EXECUTE_IF_SET_IN_BITMAP (need_assert_for, 0, i, bi)
4128 dump_asserts_for (file, ssa_name (i));
4129 fprintf (file, "\n");
4133 /* Dump all the registered assertions for all the names to stderr. */
4136 debug_all_asserts (void)
4138 dump_all_asserts (stderr);
4142 /* If NAME doesn't have an ASSERT_EXPR registered for asserting
4143 'EXPR COMP_CODE VAL' at a location that dominates block BB or
4144 E->DEST, then register this location as a possible insertion point
4145 for ASSERT_EXPR <NAME, EXPR COMP_CODE VAL>.
4147 BB, E and SI provide the exact insertion point for the new
4148 ASSERT_EXPR. If BB is NULL, then the ASSERT_EXPR is to be inserted
4149 on edge E. Otherwise, if E is NULL, the ASSERT_EXPR is inserted on
4150 BB. If SI points to a COND_EXPR or a SWITCH_EXPR statement, then E
4151 must not be NULL. */
4154 register_new_assert_for (tree name, tree expr,
4155 enum tree_code comp_code,
4159 gimple_stmt_iterator si)
4161 assert_locus_t n, loc, last_loc;
4162 basic_block dest_bb;
4164 gcc_checking_assert (bb == NULL || e == NULL);
4167 gcc_checking_assert (gimple_code (gsi_stmt (si)) != GIMPLE_COND
4168 && gimple_code (gsi_stmt (si)) != GIMPLE_SWITCH);
4170 /* Never build an assert comparing against an integer constant with
4171 TREE_OVERFLOW set. This confuses our undefined overflow warning
4173 if (TREE_CODE (val) == INTEGER_CST
4174 && TREE_OVERFLOW (val))
4175 val = build_int_cst_wide (TREE_TYPE (val),
4176 TREE_INT_CST_LOW (val), TREE_INT_CST_HIGH (val));
4178 /* The new assertion A will be inserted at BB or E. We need to
4179 determine if the new location is dominated by a previously
4180 registered location for A. If we are doing an edge insertion,
4181 assume that A will be inserted at E->DEST. Note that this is not
4184 If E is a critical edge, it will be split. But even if E is
4185 split, the new block will dominate the same set of blocks that
4188 The reverse, however, is not true, blocks dominated by E->DEST
4189 will not be dominated by the new block created to split E. So,
4190 if the insertion location is on a critical edge, we will not use
4191 the new location to move another assertion previously registered
4192 at a block dominated by E->DEST. */
4193 dest_bb = (bb) ? bb : e->dest;
4195 /* If NAME already has an ASSERT_EXPR registered for COMP_CODE and
4196 VAL at a block dominating DEST_BB, then we don't need to insert a new
4197 one. Similarly, if the same assertion already exists at a block
4198 dominated by DEST_BB and the new location is not on a critical
4199 edge, then update the existing location for the assertion (i.e.,
4200 move the assertion up in the dominance tree).
4202 Note, this is implemented as a simple linked list because there
4203 should not be more than a handful of assertions registered per
4204 name. If this becomes a performance problem, a table hashed by
4205 COMP_CODE and VAL could be implemented. */
4206 loc = asserts_for[SSA_NAME_VERSION (name)];
4210 if (loc->comp_code == comp_code
4212 || operand_equal_p (loc->val, val, 0))
4213 && (loc->expr == expr
4214 || operand_equal_p (loc->expr, expr, 0)))
4216 /* If the assertion NAME COMP_CODE VAL has already been
4217 registered at a basic block that dominates DEST_BB, then
4218 we don't need to insert the same assertion again. Note
4219 that we don't check strict dominance here to avoid
4220 replicating the same assertion inside the same basic
4221 block more than once (e.g., when a pointer is
4222 dereferenced several times inside a block).
4224 An exception to this rule are edge insertions. If the
4225 new assertion is to be inserted on edge E, then it will
4226 dominate all the other insertions that we may want to
4227 insert in DEST_BB. So, if we are doing an edge
4228 insertion, don't do this dominance check. */
4230 && dominated_by_p (CDI_DOMINATORS, dest_bb, loc->bb))
4233 /* Otherwise, if E is not a critical edge and DEST_BB
4234 dominates the existing location for the assertion, move
4235 the assertion up in the dominance tree by updating its
4236 location information. */
4237 if ((e == NULL || !EDGE_CRITICAL_P (e))
4238 && dominated_by_p (CDI_DOMINATORS, loc->bb, dest_bb))
4247 /* Update the last node of the list and move to the next one. */
4252 /* If we didn't find an assertion already registered for
4253 NAME COMP_CODE VAL, add a new one at the end of the list of
4254 assertions associated with NAME. */
4255 n = XNEW (struct assert_locus_d);
4259 n->comp_code = comp_code;
4267 asserts_for[SSA_NAME_VERSION (name)] = n;
4269 bitmap_set_bit (need_assert_for, SSA_NAME_VERSION (name));
4272 /* (COND_OP0 COND_CODE COND_OP1) is a predicate which uses NAME.
4273 Extract a suitable test code and value and store them into *CODE_P and
4274 *VAL_P so the predicate is normalized to NAME *CODE_P *VAL_P.
4276 If no extraction was possible, return FALSE, otherwise return TRUE.
4278 If INVERT is true, then we invert the result stored into *CODE_P. */
4281 extract_code_and_val_from_cond_with_ops (tree name, enum tree_code cond_code,
4282 tree cond_op0, tree cond_op1,
4283 bool invert, enum tree_code *code_p,
4286 enum tree_code comp_code;
4289 /* Otherwise, we have a comparison of the form NAME COMP VAL
4290 or VAL COMP NAME. */
4291 if (name == cond_op1)
4293 /* If the predicate is of the form VAL COMP NAME, flip
4294 COMP around because we need to register NAME as the
4295 first operand in the predicate. */
4296 comp_code = swap_tree_comparison (cond_code);
4301 /* The comparison is of the form NAME COMP VAL, so the
4302 comparison code remains unchanged. */
4303 comp_code = cond_code;
4307 /* Invert the comparison code as necessary. */
4309 comp_code = invert_tree_comparison (comp_code, 0);
4311 /* VRP does not handle float types. */
4312 if (SCALAR_FLOAT_TYPE_P (TREE_TYPE (val)))
4315 /* Do not register always-false predicates.
4316 FIXME: this works around a limitation in fold() when dealing with
4317 enumerations. Given 'enum { N1, N2 } x;', fold will not
4318 fold 'if (x > N2)' to 'if (0)'. */
4319 if ((comp_code == GT_EXPR || comp_code == LT_EXPR)
4320 && INTEGRAL_TYPE_P (TREE_TYPE (val)))
4322 tree min = TYPE_MIN_VALUE (TREE_TYPE (val));
4323 tree max = TYPE_MAX_VALUE (TREE_TYPE (val));
4325 if (comp_code == GT_EXPR
4327 || compare_values (val, max) == 0))
4330 if (comp_code == LT_EXPR
4332 || compare_values (val, min) == 0))
4335 *code_p = comp_code;
4340 /* Try to register an edge assertion for SSA name NAME on edge E for
4341 the condition COND contributing to the conditional jump pointed to by BSI.
4342 Invert the condition COND if INVERT is true.
4343 Return true if an assertion for NAME could be registered. */
4346 register_edge_assert_for_2 (tree name, edge e, gimple_stmt_iterator bsi,
4347 enum tree_code cond_code,
4348 tree cond_op0, tree cond_op1, bool invert)
4351 enum tree_code comp_code;
4352 bool retval = false;
4354 if (!extract_code_and_val_from_cond_with_ops (name, cond_code,
4357 invert, &comp_code, &val))
4360 /* Only register an ASSERT_EXPR if NAME was found in the sub-graph
4361 reachable from E. */
4362 if (live_on_edge (e, name)
4363 && !has_single_use (name))
4365 register_new_assert_for (name, name, comp_code, val, NULL, e, bsi);
4369 /* In the case of NAME <= CST and NAME being defined as
4370 NAME = (unsigned) NAME2 + CST2 we can assert NAME2 >= -CST2
4371 and NAME2 <= CST - CST2. We can do the same for NAME > CST.
4372 This catches range and anti-range tests. */
4373 if ((comp_code == LE_EXPR
4374 || comp_code == GT_EXPR)
4375 && TREE_CODE (val) == INTEGER_CST
4376 && TYPE_UNSIGNED (TREE_TYPE (val)))
4378 gimple def_stmt = SSA_NAME_DEF_STMT (name);
4379 tree cst2 = NULL_TREE, name2 = NULL_TREE, name3 = NULL_TREE;
4381 /* Extract CST2 from the (optional) addition. */
4382 if (is_gimple_assign (def_stmt)
4383 && gimple_assign_rhs_code (def_stmt) == PLUS_EXPR)
4385 name2 = gimple_assign_rhs1 (def_stmt);
4386 cst2 = gimple_assign_rhs2 (def_stmt);
4387 if (TREE_CODE (name2) == SSA_NAME
4388 && TREE_CODE (cst2) == INTEGER_CST)
4389 def_stmt = SSA_NAME_DEF_STMT (name2);
4392 /* Extract NAME2 from the (optional) sign-changing cast. */
4393 if (gimple_assign_cast_p (def_stmt))
4395 if (CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (def_stmt))
4396 && ! TYPE_UNSIGNED (TREE_TYPE (gimple_assign_rhs1 (def_stmt)))
4397 && (TYPE_PRECISION (gimple_expr_type (def_stmt))
4398 == TYPE_PRECISION (TREE_TYPE (gimple_assign_rhs1 (def_stmt)))))
4399 name3 = gimple_assign_rhs1 (def_stmt);
4402 /* If name3 is used later, create an ASSERT_EXPR for it. */
4403 if (name3 != NULL_TREE
4404 && TREE_CODE (name3) == SSA_NAME
4405 && (cst2 == NULL_TREE
4406 || TREE_CODE (cst2) == INTEGER_CST)
4407 && INTEGRAL_TYPE_P (TREE_TYPE (name3))
4408 && live_on_edge (e, name3)
4409 && !has_single_use (name3))
4413 /* Build an expression for the range test. */
4414 tmp = build1 (NOP_EXPR, TREE_TYPE (name), name3);
4415 if (cst2 != NULL_TREE)
4416 tmp = build2 (PLUS_EXPR, TREE_TYPE (name), tmp, cst2);
4420 fprintf (dump_file, "Adding assert for ");
4421 print_generic_expr (dump_file, name3, 0);
4422 fprintf (dump_file, " from ");
4423 print_generic_expr (dump_file, tmp, 0);
4424 fprintf (dump_file, "\n");
4427 register_new_assert_for (name3, tmp, comp_code, val, NULL, e, bsi);
4432 /* If name2 is used later, create an ASSERT_EXPR for it. */
4433 if (name2 != NULL_TREE
4434 && TREE_CODE (name2) == SSA_NAME
4435 && TREE_CODE (cst2) == INTEGER_CST
4436 && INTEGRAL_TYPE_P (TREE_TYPE (name2))
4437 && live_on_edge (e, name2)
4438 && !has_single_use (name2))
4442 /* Build an expression for the range test. */
4444 if (TREE_TYPE (name) != TREE_TYPE (name2))
4445 tmp = build1 (NOP_EXPR, TREE_TYPE (name), tmp);
4446 if (cst2 != NULL_TREE)
4447 tmp = build2 (PLUS_EXPR, TREE_TYPE (name), tmp, cst2);
4451 fprintf (dump_file, "Adding assert for ");
4452 print_generic_expr (dump_file, name2, 0);
4453 fprintf (dump_file, " from ");
4454 print_generic_expr (dump_file, tmp, 0);
4455 fprintf (dump_file, "\n");
4458 register_new_assert_for (name2, tmp, comp_code, val, NULL, e, bsi);
4467 /* OP is an operand of a truth value expression which is known to have
4468 a particular value. Register any asserts for OP and for any
4469 operands in OP's defining statement.
4471 If CODE is EQ_EXPR, then we want to register OP is zero (false),
4472 if CODE is NE_EXPR, then we want to register OP is nonzero (true). */
4475 register_edge_assert_for_1 (tree op, enum tree_code code,
4476 edge e, gimple_stmt_iterator bsi)
4478 bool retval = false;
4481 enum tree_code rhs_code;
4483 /* We only care about SSA_NAMEs. */
4484 if (TREE_CODE (op) != SSA_NAME)
4487 /* We know that OP will have a zero or nonzero value. If OP is used
4488 more than once go ahead and register an assert for OP.
4490 The FOUND_IN_SUBGRAPH support is not helpful in this situation as
4491 it will always be set for OP (because OP is used in a COND_EXPR in
4493 if (!has_single_use (op))
4495 val = build_int_cst (TREE_TYPE (op), 0);
4496 register_new_assert_for (op, op, code, val, NULL, e, bsi);
4500 /* Now look at how OP is set. If it's set from a comparison,
4501 a truth operation or some bit operations, then we may be able
4502 to register information about the operands of that assignment. */
4503 op_def = SSA_NAME_DEF_STMT (op);
4504 if (gimple_code (op_def) != GIMPLE_ASSIGN)
4507 rhs_code = gimple_assign_rhs_code (op_def);
4509 if (TREE_CODE_CLASS (rhs_code) == tcc_comparison)
4511 bool invert = (code == EQ_EXPR ? true : false);
4512 tree op0 = gimple_assign_rhs1 (op_def);
4513 tree op1 = gimple_assign_rhs2 (op_def);
4515 if (TREE_CODE (op0) == SSA_NAME)
4516 retval |= register_edge_assert_for_2 (op0, e, bsi, rhs_code, op0, op1,
4518 if (TREE_CODE (op1) == SSA_NAME)
4519 retval |= register_edge_assert_for_2 (op1, e, bsi, rhs_code, op0, op1,
4522 else if ((code == NE_EXPR
4523 && gimple_assign_rhs_code (op_def) == BIT_AND_EXPR)
4525 && gimple_assign_rhs_code (op_def) == BIT_IOR_EXPR))
4527 /* Recurse on each operand. */
4528 retval |= register_edge_assert_for_1 (gimple_assign_rhs1 (op_def),
4530 retval |= register_edge_assert_for_1 (gimple_assign_rhs2 (op_def),
4533 else if (gimple_assign_rhs_code (op_def) == BIT_NOT_EXPR
4534 && TYPE_PRECISION (TREE_TYPE (gimple_assign_lhs (op_def))) == 1)
4536 /* Recurse, flipping CODE. */
4537 code = invert_tree_comparison (code, false);
4538 retval |= register_edge_assert_for_1 (gimple_assign_rhs1 (op_def),
4541 else if (gimple_assign_rhs_code (op_def) == SSA_NAME)
4543 /* Recurse through the copy. */
4544 retval |= register_edge_assert_for_1 (gimple_assign_rhs1 (op_def),
4547 else if (CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (op_def)))
4549 /* Recurse through the type conversion. */
4550 retval |= register_edge_assert_for_1 (gimple_assign_rhs1 (op_def),
4557 /* Try to register an edge assertion for SSA name NAME on edge E for
4558 the condition COND contributing to the conditional jump pointed to by SI.
4559 Return true if an assertion for NAME could be registered. */
4562 register_edge_assert_for (tree name, edge e, gimple_stmt_iterator si,
4563 enum tree_code cond_code, tree cond_op0,
4567 enum tree_code comp_code;
4568 bool retval = false;
4569 bool is_else_edge = (e->flags & EDGE_FALSE_VALUE) != 0;
4571 /* Do not attempt to infer anything in names that flow through
4573 if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (name))
4576 if (!extract_code_and_val_from_cond_with_ops (name, cond_code,
4582 /* Register ASSERT_EXPRs for name. */
4583 retval |= register_edge_assert_for_2 (name, e, si, cond_code, cond_op0,
4584 cond_op1, is_else_edge);
4587 /* If COND is effectively an equality test of an SSA_NAME against
4588 the value zero or one, then we may be able to assert values
4589 for SSA_NAMEs which flow into COND. */
4591 /* In the case of NAME == 1 or NAME != 0, for BIT_AND_EXPR defining
4592 statement of NAME we can assert both operands of the BIT_AND_EXPR
4593 have nonzero value. */
4594 if (((comp_code == EQ_EXPR && integer_onep (val))
4595 || (comp_code == NE_EXPR && integer_zerop (val))))
4597 gimple def_stmt = SSA_NAME_DEF_STMT (name);
4599 if (is_gimple_assign (def_stmt)
4600 && gimple_assign_rhs_code (def_stmt) == BIT_AND_EXPR)
4602 tree op0 = gimple_assign_rhs1 (def_stmt);
4603 tree op1 = gimple_assign_rhs2 (def_stmt);
4604 retval |= register_edge_assert_for_1 (op0, NE_EXPR, e, si);
4605 retval |= register_edge_assert_for_1 (op1, NE_EXPR, e, si);
4609 /* In the case of NAME == 0 or NAME != 1, for BIT_IOR_EXPR defining
4610 statement of NAME we can assert both operands of the BIT_IOR_EXPR
4612 if (((comp_code == EQ_EXPR && integer_zerop (val))
4613 || (comp_code == NE_EXPR && integer_onep (val))))
4615 gimple def_stmt = SSA_NAME_DEF_STMT (name);
4617 /* For BIT_IOR_EXPR only if NAME == 0 both operands have
4618 necessarily zero value, or if type-precision is one. */
4619 if (is_gimple_assign (def_stmt)
4620 && (gimple_assign_rhs_code (def_stmt) == BIT_IOR_EXPR
4621 && (TYPE_PRECISION (TREE_TYPE (name)) == 1
4622 || comp_code == EQ_EXPR)))
4624 tree op0 = gimple_assign_rhs1 (def_stmt);
4625 tree op1 = gimple_assign_rhs2 (def_stmt);
4626 retval |= register_edge_assert_for_1 (op0, EQ_EXPR, e, si);
4627 retval |= register_edge_assert_for_1 (op1, EQ_EXPR, e, si);
4635 /* Determine whether the outgoing edges of BB should receive an
4636 ASSERT_EXPR for each of the operands of BB's LAST statement.
4637 The last statement of BB must be a COND_EXPR.
4639 If any of the sub-graphs rooted at BB have an interesting use of
4640 the predicate operands, an assert location node is added to the
4641 list of assertions for the corresponding operands. */
4644 find_conditional_asserts (basic_block bb, gimple last)
4647 gimple_stmt_iterator bsi;
4653 need_assert = false;
4654 bsi = gsi_for_stmt (last);
4656 /* Look for uses of the operands in each of the sub-graphs
4657 rooted at BB. We need to check each of the outgoing edges
4658 separately, so that we know what kind of ASSERT_EXPR to
4660 FOR_EACH_EDGE (e, ei, bb->succs)
4665 /* Register the necessary assertions for each operand in the
4666 conditional predicate. */
4667 FOR_EACH_SSA_TREE_OPERAND (op, last, iter, SSA_OP_USE)
4669 need_assert |= register_edge_assert_for (op, e, bsi,
4670 gimple_cond_code (last),
4671 gimple_cond_lhs (last),
4672 gimple_cond_rhs (last));
4685 /* Compare two case labels sorting first by the destination bb index
4686 and then by the case value. */
4689 compare_case_labels (const void *p1, const void *p2)
4691 const struct case_info *ci1 = (const struct case_info *) p1;
4692 const struct case_info *ci2 = (const struct case_info *) p2;
4693 int idx1 = ci1->bb->index;
4694 int idx2 = ci2->bb->index;
4698 else if (idx1 == idx2)
4700 /* Make sure the default label is first in a group. */
4701 if (!CASE_LOW (ci1->expr))
4703 else if (!CASE_LOW (ci2->expr))
4706 return tree_int_cst_compare (CASE_LOW (ci1->expr),
4707 CASE_LOW (ci2->expr));
4713 /* Determine whether the outgoing edges of BB should receive an
4714 ASSERT_EXPR for each of the operands of BB's LAST statement.
4715 The last statement of BB must be a SWITCH_EXPR.
4717 If any of the sub-graphs rooted at BB have an interesting use of
4718 the predicate operands, an assert location node is added to the
4719 list of assertions for the corresponding operands. */
4722 find_switch_asserts (basic_block bb, gimple last)
4725 gimple_stmt_iterator bsi;
4728 struct case_info *ci;
4729 size_t n = gimple_switch_num_labels (last);
4730 #if GCC_VERSION >= 4000
4733 /* Work around GCC 3.4 bug (PR 37086). */
4734 volatile unsigned int idx;
4737 need_assert = false;
4738 bsi = gsi_for_stmt (last);
4739 op = gimple_switch_index (last);
4740 if (TREE_CODE (op) != SSA_NAME)
4743 /* Build a vector of case labels sorted by destination label. */
4744 ci = XNEWVEC (struct case_info, n);
4745 for (idx = 0; idx < n; ++idx)
4747 ci[idx].expr = gimple_switch_label (last, idx);
4748 ci[idx].bb = label_to_block (CASE_LABEL (ci[idx].expr));
4750 qsort (ci, n, sizeof (struct case_info), compare_case_labels);
4752 for (idx = 0; idx < n; ++idx)
4755 tree cl = ci[idx].expr;
4756 basic_block cbb = ci[idx].bb;
4758 min = CASE_LOW (cl);
4759 max = CASE_HIGH (cl);
4761 /* If there are multiple case labels with the same destination
4762 we need to combine them to a single value range for the edge. */
4763 if (idx + 1 < n && cbb == ci[idx + 1].bb)
4765 /* Skip labels until the last of the group. */
4768 } while (idx < n && cbb == ci[idx].bb);
4771 /* Pick up the maximum of the case label range. */
4772 if (CASE_HIGH (ci[idx].expr))
4773 max = CASE_HIGH (ci[idx].expr);
4775 max = CASE_LOW (ci[idx].expr);
4778 /* Nothing to do if the range includes the default label until we
4779 can register anti-ranges. */
4780 if (min == NULL_TREE)
4783 /* Find the edge to register the assert expr on. */
4784 e = find_edge (bb, cbb);
4786 /* Register the necessary assertions for the operand in the
4788 need_assert |= register_edge_assert_for (op, e, bsi,
4789 max ? GE_EXPR : EQ_EXPR,
4791 fold_convert (TREE_TYPE (op),
4795 need_assert |= register_edge_assert_for (op, e, bsi, LE_EXPR,
4797 fold_convert (TREE_TYPE (op),
4807 /* Traverse all the statements in block BB looking for statements that
4808 may generate useful assertions for the SSA names in their operand.
4809 If a statement produces a useful assertion A for name N_i, then the
4810 list of assertions already generated for N_i is scanned to
4811 determine if A is actually needed.
4813 If N_i already had the assertion A at a location dominating the
4814 current location, then nothing needs to be done. Otherwise, the
4815 new location for A is recorded instead.
4817 1- For every statement S in BB, all the variables used by S are
4818 added to bitmap FOUND_IN_SUBGRAPH.
4820 2- If statement S uses an operand N in a way that exposes a known
4821 value range for N, then if N was not already generated by an
4822 ASSERT_EXPR, create a new assert location for N. For instance,
4823 if N is a pointer and the statement dereferences it, we can
4824 assume that N is not NULL.
4826 3- COND_EXPRs are a special case of #2. We can derive range
4827 information from the predicate but need to insert different
4828 ASSERT_EXPRs for each of the sub-graphs rooted at the
4829 conditional block. If the last statement of BB is a conditional
4830 expression of the form 'X op Y', then
4832 a) Remove X and Y from the set FOUND_IN_SUBGRAPH.
4834 b) If the conditional is the only entry point to the sub-graph
4835 corresponding to the THEN_CLAUSE, recurse into it. On
4836 return, if X and/or Y are marked in FOUND_IN_SUBGRAPH, then
4837 an ASSERT_EXPR is added for the corresponding variable.
4839 c) Repeat step (b) on the ELSE_CLAUSE.
4841 d) Mark X and Y in FOUND_IN_SUBGRAPH.
4850 In this case, an assertion on the THEN clause is useful to
4851 determine that 'a' is always 9 on that edge. However, an assertion
4852 on the ELSE clause would be unnecessary.
4854 4- If BB does not end in a conditional expression, then we recurse
4855 into BB's dominator children.
4857 At the end of the recursive traversal, every SSA name will have a
4858 list of locations where ASSERT_EXPRs should be added. When a new
4859 location for name N is found, it is registered by calling
4860 register_new_assert_for. That function keeps track of all the
4861 registered assertions to prevent adding unnecessary assertions.
4862 For instance, if a pointer P_4 is dereferenced more than once in a
4863 dominator tree, only the location dominating all the dereference of
4864 P_4 will receive an ASSERT_EXPR.
4866 If this function returns true, then it means that there are names
4867 for which we need to generate ASSERT_EXPRs. Those assertions are
4868 inserted by process_assert_insertions. */
4871 find_assert_locations_1 (basic_block bb, sbitmap live)
4873 gimple_stmt_iterator si;
4878 need_assert = false;
4879 last = last_stmt (bb);
4881 /* If BB's last statement is a conditional statement involving integer
4882 operands, determine if we need to add ASSERT_EXPRs. */
4884 && gimple_code (last) == GIMPLE_COND
4885 && !fp_predicate (last)
4886 && !ZERO_SSA_OPERANDS (last, SSA_OP_USE))
4887 need_assert |= find_conditional_asserts (bb, last);
4889 /* If BB's last statement is a switch statement involving integer
4890 operands, determine if we need to add ASSERT_EXPRs. */
4892 && gimple_code (last) == GIMPLE_SWITCH
4893 && !ZERO_SSA_OPERANDS (last, SSA_OP_USE))
4894 need_assert |= find_switch_asserts (bb, last);
4896 /* Traverse all the statements in BB marking used names and looking
4897 for statements that may infer assertions for their used operands. */
4898 for (si = gsi_start_bb (bb); !gsi_end_p (si); gsi_next (&si))
4904 stmt = gsi_stmt (si);
4906 if (is_gimple_debug (stmt))
4909 /* See if we can derive an assertion for any of STMT's operands. */
4910 FOR_EACH_SSA_TREE_OPERAND (op, stmt, i, SSA_OP_USE)
4913 enum tree_code comp_code;
4915 /* Mark OP in our live bitmap. */
4916 SET_BIT (live, SSA_NAME_VERSION (op));
4918 /* If OP is used in such a way that we can infer a value
4919 range for it, and we don't find a previous assertion for
4920 it, create a new assertion location node for OP. */
4921 if (infer_value_range (stmt, op, &comp_code, &value))
4923 /* If we are able to infer a nonzero value range for OP,
4924 then walk backwards through the use-def chain to see if OP
4925 was set via a typecast.
4927 If so, then we can also infer a nonzero value range
4928 for the operand of the NOP_EXPR. */
4929 if (comp_code == NE_EXPR && integer_zerop (value))
4932 gimple def_stmt = SSA_NAME_DEF_STMT (t);
4934 while (is_gimple_assign (def_stmt)
4935 && gimple_assign_rhs_code (def_stmt) == NOP_EXPR
4937 (gimple_assign_rhs1 (def_stmt)) == SSA_NAME
4939 (TREE_TYPE (gimple_assign_rhs1 (def_stmt))))
4941 t = gimple_assign_rhs1 (def_stmt);
4942 def_stmt = SSA_NAME_DEF_STMT (t);
4944 /* Note we want to register the assert for the
4945 operand of the NOP_EXPR after SI, not after the
4947 if (! has_single_use (t))
4949 register_new_assert_for (t, t, comp_code, value,
4956 /* If OP is used only once, namely in this STMT, don't
4957 bother creating an ASSERT_EXPR for it. Such an
4958 ASSERT_EXPR would do nothing but increase compile time. */
4959 if (!has_single_use (op))
4961 register_new_assert_for (op, op, comp_code, value,
4969 /* Traverse all PHI nodes in BB marking used operands. */
4970 for (si = gsi_start_phis (bb); !gsi_end_p(si); gsi_next (&si))
4972 use_operand_p arg_p;
4974 phi = gsi_stmt (si);
4976 FOR_EACH_PHI_ARG (arg_p, phi, i, SSA_OP_USE)
4978 tree arg = USE_FROM_PTR (arg_p);
4979 if (TREE_CODE (arg) == SSA_NAME)
4980 SET_BIT (live, SSA_NAME_VERSION (arg));
4987 /* Do an RPO walk over the function computing SSA name liveness
4988 on-the-fly and deciding on assert expressions to insert.
4989 Returns true if there are assert expressions to be inserted. */
4992 find_assert_locations (void)
4994 int *rpo = XCNEWVEC (int, last_basic_block + NUM_FIXED_BLOCKS);
4995 int *bb_rpo = XCNEWVEC (int, last_basic_block + NUM_FIXED_BLOCKS);
4996 int *last_rpo = XCNEWVEC (int, last_basic_block + NUM_FIXED_BLOCKS);
5000 live = XCNEWVEC (sbitmap, last_basic_block + NUM_FIXED_BLOCKS);
5001 rpo_cnt = pre_and_rev_post_order_compute (NULL, rpo, false);
5002 for (i = 0; i < rpo_cnt; ++i)
5005 need_asserts = false;
5006 for (i = rpo_cnt-1; i >= 0; --i)
5008 basic_block bb = BASIC_BLOCK (rpo[i]);
5014 live[rpo[i]] = sbitmap_alloc (num_ssa_names);
5015 sbitmap_zero (live[rpo[i]]);
5018 /* Process BB and update the live information with uses in
5020 need_asserts |= find_assert_locations_1 (bb, live[rpo[i]]);
5022 /* Merge liveness into the predecessor blocks and free it. */
5023 if (!sbitmap_empty_p (live[rpo[i]]))
5026 FOR_EACH_EDGE (e, ei, bb->preds)
5028 int pred = e->src->index;
5029 if (e->flags & EDGE_DFS_BACK)
5034 live[pred] = sbitmap_alloc (num_ssa_names);
5035 sbitmap_zero (live[pred]);
5037 sbitmap_a_or_b (live[pred], live[pred], live[rpo[i]]);
5039 if (bb_rpo[pred] < pred_rpo)
5040 pred_rpo = bb_rpo[pred];
5043 /* Record the RPO number of the last visited block that needs
5044 live information from this block. */
5045 last_rpo[rpo[i]] = pred_rpo;
5049 sbitmap_free (live[rpo[i]]);
5050 live[rpo[i]] = NULL;
5053 /* We can free all successors live bitmaps if all their
5054 predecessors have been visited already. */
5055 FOR_EACH_EDGE (e, ei, bb->succs)
5056 if (last_rpo[e->dest->index] == i
5057 && live[e->dest->index])
5059 sbitmap_free (live[e->dest->index]);
5060 live[e->dest->index] = NULL;
5065 XDELETEVEC (bb_rpo);
5066 XDELETEVEC (last_rpo);
5067 for (i = 0; i < last_basic_block + NUM_FIXED_BLOCKS; ++i)
5069 sbitmap_free (live[i]);
5072 return need_asserts;
5075 /* Create an ASSERT_EXPR for NAME and insert it in the location
5076 indicated by LOC. Return true if we made any edge insertions. */
5079 process_assert_insertions_for (tree name, assert_locus_t loc)
5081 /* Build the comparison expression NAME_i COMP_CODE VAL. */
5088 /* If we have X <=> X do not insert an assert expr for that. */
5089 if (loc->expr == loc->val)
5092 cond = build2 (loc->comp_code, boolean_type_node, loc->expr, loc->val);
5093 assert_stmt = build_assert_expr_for (cond, name);
5096 /* We have been asked to insert the assertion on an edge. This
5097 is used only by COND_EXPR and SWITCH_EXPR assertions. */
5098 gcc_checking_assert (gimple_code (gsi_stmt (loc->si)) == GIMPLE_COND
5099 || (gimple_code (gsi_stmt (loc->si))
5102 gsi_insert_on_edge (loc->e, assert_stmt);
5106 /* Otherwise, we can insert right after LOC->SI iff the
5107 statement must not be the last statement in the block. */
5108 stmt = gsi_stmt (loc->si);
5109 if (!stmt_ends_bb_p (stmt))
5111 gsi_insert_after (&loc->si, assert_stmt, GSI_SAME_STMT);
5115 /* If STMT must be the last statement in BB, we can only insert new
5116 assertions on the non-abnormal edge out of BB. Note that since
5117 STMT is not control flow, there may only be one non-abnormal edge
5119 FOR_EACH_EDGE (e, ei, loc->bb->succs)
5120 if (!(e->flags & EDGE_ABNORMAL))
5122 gsi_insert_on_edge (e, assert_stmt);
5130 /* Process all the insertions registered for every name N_i registered
5131 in NEED_ASSERT_FOR. The list of assertions to be inserted are
5132 found in ASSERTS_FOR[i]. */
5135 process_assert_insertions (void)
5139 bool update_edges_p = false;
5140 int num_asserts = 0;
5142 if (dump_file && (dump_flags & TDF_DETAILS))
5143 dump_all_asserts (dump_file);
5145 EXECUTE_IF_SET_IN_BITMAP (need_assert_for, 0, i, bi)
5147 assert_locus_t loc = asserts_for[i];
5152 assert_locus_t next = loc->next;
5153 update_edges_p |= process_assert_insertions_for (ssa_name (i), loc);
5161 gsi_commit_edge_inserts ();
5163 statistics_counter_event (cfun, "Number of ASSERT_EXPR expressions inserted",
5168 /* Traverse the flowgraph looking for conditional jumps to insert range
5169 expressions. These range expressions are meant to provide information
5170 to optimizations that need to reason in terms of value ranges. They
5171 will not be expanded into RTL. For instance, given:
5180 this pass will transform the code into:
5186 x = ASSERT_EXPR <x, x < y>
5191 y = ASSERT_EXPR <y, x <= y>
5195 The idea is that once copy and constant propagation have run, other
5196 optimizations will be able to determine what ranges of values can 'x'
5197 take in different paths of the code, simply by checking the reaching
5198 definition of 'x'. */
5201 insert_range_assertions (void)
5203 need_assert_for = BITMAP_ALLOC (NULL);
5204 asserts_for = XCNEWVEC (assert_locus_t, num_ssa_names);
5206 calculate_dominance_info (CDI_DOMINATORS);
5208 if (find_assert_locations ())
5210 process_assert_insertions ();
5211 update_ssa (TODO_update_ssa_no_phi);
5214 if (dump_file && (dump_flags & TDF_DETAILS))
5216 fprintf (dump_file, "\nSSA form after inserting ASSERT_EXPRs\n");
5217 dump_function_to_file (current_function_decl, dump_file, dump_flags);
5221 BITMAP_FREE (need_assert_for);
5224 /* Checks one ARRAY_REF in REF, located at LOCUS. Ignores flexible arrays
5225 and "struct" hacks. If VRP can determine that the
5226 array subscript is a constant, check if it is outside valid
5227 range. If the array subscript is a RANGE, warn if it is
5228 non-overlapping with valid range.
5229 IGNORE_OFF_BY_ONE is true if the ARRAY_REF is inside a ADDR_EXPR. */
5232 check_array_ref (location_t location, tree ref, bool ignore_off_by_one)
5234 value_range_t* vr = NULL;
5235 tree low_sub, up_sub;
5236 tree low_bound, up_bound, up_bound_p1;
5239 if (TREE_NO_WARNING (ref))
5242 low_sub = up_sub = TREE_OPERAND (ref, 1);
5243 up_bound = array_ref_up_bound (ref);
5245 /* Can not check flexible arrays. */
5247 || TREE_CODE (up_bound) != INTEGER_CST)
5250 /* Accesses to trailing arrays via pointers may access storage
5251 beyond the types array bounds. */
5252 base = get_base_address (ref);
5253 if (base && TREE_CODE (base) == MEM_REF)
5255 tree cref, next = NULL_TREE;
5257 if (TREE_CODE (TREE_OPERAND (ref, 0)) != COMPONENT_REF)
5260 cref = TREE_OPERAND (ref, 0);
5261 if (TREE_CODE (TREE_TYPE (TREE_OPERAND (cref, 0))) == RECORD_TYPE)
5262 for (next = DECL_CHAIN (TREE_OPERAND (cref, 1));
5263 next && TREE_CODE (next) != FIELD_DECL;
5264 next = DECL_CHAIN (next))
5267 /* If this is the last field in a struct type or a field in a
5268 union type do not warn. */
5273 low_bound = array_ref_low_bound (ref);
5274 up_bound_p1 = int_const_binop (PLUS_EXPR, up_bound, integer_one_node);
5276 if (TREE_CODE (low_sub) == SSA_NAME)
5278 vr = get_value_range (low_sub);
5279 if (vr->type == VR_RANGE || vr->type == VR_ANTI_RANGE)
5281 low_sub = vr->type == VR_RANGE ? vr->max : vr->min;
5282 up_sub = vr->type == VR_RANGE ? vr->min : vr->max;
5286 if (vr && vr->type == VR_ANTI_RANGE)
5288 if (TREE_CODE (up_sub) == INTEGER_CST
5289 && tree_int_cst_lt (up_bound, up_sub)
5290 && TREE_CODE (low_sub) == INTEGER_CST
5291 && tree_int_cst_lt (low_sub, low_bound))
5293 warning_at (location, OPT_Warray_bounds,
5294 "array subscript is outside array bounds");
5295 TREE_NO_WARNING (ref) = 1;
5298 else if (TREE_CODE (up_sub) == INTEGER_CST
5299 && (ignore_off_by_one
5300 ? (tree_int_cst_lt (up_bound, up_sub)
5301 && !tree_int_cst_equal (up_bound_p1, up_sub))
5302 : (tree_int_cst_lt (up_bound, up_sub)
5303 || tree_int_cst_equal (up_bound_p1, up_sub))))
5305 warning_at (location, OPT_Warray_bounds,
5306 "array subscript is above array bounds");
5307 TREE_NO_WARNING (ref) = 1;
5309 else if (TREE_CODE (low_sub) == INTEGER_CST
5310 && tree_int_cst_lt (low_sub, low_bound))
5312 warning_at (location, OPT_Warray_bounds,
5313 "array subscript is below array bounds");
5314 TREE_NO_WARNING (ref) = 1;
5318 /* Searches if the expr T, located at LOCATION computes
5319 address of an ARRAY_REF, and call check_array_ref on it. */
5322 search_for_addr_array (tree t, location_t location)
5324 while (TREE_CODE (t) == SSA_NAME)
5326 gimple g = SSA_NAME_DEF_STMT (t);
5328 if (gimple_code (g) != GIMPLE_ASSIGN)
5331 if (get_gimple_rhs_class (gimple_assign_rhs_code (g))
5332 != GIMPLE_SINGLE_RHS)
5335 t = gimple_assign_rhs1 (g);
5339 /* We are only interested in addresses of ARRAY_REF's. */
5340 if (TREE_CODE (t) != ADDR_EXPR)
5343 /* Check each ARRAY_REFs in the reference chain. */
5346 if (TREE_CODE (t) == ARRAY_REF)
5347 check_array_ref (location, t, true /*ignore_off_by_one*/);
5349 t = TREE_OPERAND (t, 0);
5351 while (handled_component_p (t));
5353 if (TREE_CODE (t) == MEM_REF
5354 && TREE_CODE (TREE_OPERAND (t, 0)) == ADDR_EXPR
5355 && !TREE_NO_WARNING (t))
5357 tree tem = TREE_OPERAND (TREE_OPERAND (t, 0), 0);
5358 tree low_bound, up_bound, el_sz;
5360 if (TREE_CODE (TREE_TYPE (tem)) != ARRAY_TYPE
5361 || TREE_CODE (TREE_TYPE (TREE_TYPE (tem))) == ARRAY_TYPE
5362 || !TYPE_DOMAIN (TREE_TYPE (tem)))
5365 low_bound = TYPE_MIN_VALUE (TYPE_DOMAIN (TREE_TYPE (tem)));
5366 up_bound = TYPE_MAX_VALUE (TYPE_DOMAIN (TREE_TYPE (tem)));
5367 el_sz = TYPE_SIZE_UNIT (TREE_TYPE (TREE_TYPE (tem)));
5369 || TREE_CODE (low_bound) != INTEGER_CST
5371 || TREE_CODE (up_bound) != INTEGER_CST
5373 || TREE_CODE (el_sz) != INTEGER_CST)
5376 idx = mem_ref_offset (t);
5377 idx = double_int_sdiv (idx, tree_to_double_int (el_sz), TRUNC_DIV_EXPR);
5378 if (double_int_scmp (idx, double_int_zero) < 0)
5380 warning_at (location, OPT_Warray_bounds,
5381 "array subscript is below array bounds");
5382 TREE_NO_WARNING (t) = 1;
5384 else if (double_int_scmp (idx,
5387 (tree_to_double_int (up_bound),
5389 (tree_to_double_int (low_bound))),
5390 double_int_one)) > 0)
5392 warning_at (location, OPT_Warray_bounds,
5393 "array subscript is above array bounds");
5394 TREE_NO_WARNING (t) = 1;
5399 /* walk_tree() callback that checks if *TP is
5400 an ARRAY_REF inside an ADDR_EXPR (in which an array
5401 subscript one outside the valid range is allowed). Call
5402 check_array_ref for each ARRAY_REF found. The location is
5406 check_array_bounds (tree *tp, int *walk_subtree, void *data)
5409 struct walk_stmt_info *wi = (struct walk_stmt_info *) data;
5410 location_t location;
5412 if (EXPR_HAS_LOCATION (t))
5413 location = EXPR_LOCATION (t);
5416 location_t *locp = (location_t *) wi->info;
5420 *walk_subtree = TRUE;
5422 if (TREE_CODE (t) == ARRAY_REF)
5423 check_array_ref (location, t, false /*ignore_off_by_one*/);
5425 if (TREE_CODE (t) == MEM_REF
5426 || (TREE_CODE (t) == RETURN_EXPR && TREE_OPERAND (t, 0)))
5427 search_for_addr_array (TREE_OPERAND (t, 0), location);
5429 if (TREE_CODE (t) == ADDR_EXPR)
5430 *walk_subtree = FALSE;
5435 /* Walk over all statements of all reachable BBs and call check_array_bounds
5439 check_all_array_refs (void)
5442 gimple_stmt_iterator si;
5448 bool executable = false;
5450 /* Skip blocks that were found to be unreachable. */
5451 FOR_EACH_EDGE (e, ei, bb->preds)
5452 executable |= !!(e->flags & EDGE_EXECUTABLE);
5456 for (si = gsi_start_bb (bb); !gsi_end_p (si); gsi_next (&si))
5458 gimple stmt = gsi_stmt (si);
5459 struct walk_stmt_info wi;
5460 if (!gimple_has_location (stmt))
5463 if (is_gimple_call (stmt))
5466 size_t n = gimple_call_num_args (stmt);
5467 for (i = 0; i < n; i++)
5469 tree arg = gimple_call_arg (stmt, i);
5470 search_for_addr_array (arg, gimple_location (stmt));
5475 memset (&wi, 0, sizeof (wi));
5476 wi.info = CONST_CAST (void *, (const void *)
5477 gimple_location_ptr (stmt));
5479 walk_gimple_op (gsi_stmt (si),
5487 /* Convert range assertion expressions into the implied copies and
5488 copy propagate away the copies. Doing the trivial copy propagation
5489 here avoids the need to run the full copy propagation pass after
5492 FIXME, this will eventually lead to copy propagation removing the
5493 names that had useful range information attached to them. For
5494 instance, if we had the assertion N_i = ASSERT_EXPR <N_j, N_j > 3>,
5495 then N_i will have the range [3, +INF].
5497 However, by converting the assertion into the implied copy
5498 operation N_i = N_j, we will then copy-propagate N_j into the uses
5499 of N_i and lose the range information. We may want to hold on to
5500 ASSERT_EXPRs a little while longer as the ranges could be used in
5501 things like jump threading.
5503 The problem with keeping ASSERT_EXPRs around is that passes after
5504 VRP need to handle them appropriately.
5506 Another approach would be to make the range information a first
5507 class property of the SSA_NAME so that it can be queried from
5508 any pass. This is made somewhat more complex by the need for
5509 multiple ranges to be associated with one SSA_NAME. */
5512 remove_range_assertions (void)
5515 gimple_stmt_iterator si;
5517 /* Note that the BSI iterator bump happens at the bottom of the
5518 loop and no bump is necessary if we're removing the statement
5519 referenced by the current BSI. */
5521 for (si = gsi_start_bb (bb); !gsi_end_p (si);)
5523 gimple stmt = gsi_stmt (si);
5526 if (is_gimple_assign (stmt)
5527 && gimple_assign_rhs_code (stmt) == ASSERT_EXPR)
5529 tree rhs = gimple_assign_rhs1 (stmt);
5531 tree cond = fold (ASSERT_EXPR_COND (rhs));
5532 use_operand_p use_p;
5533 imm_use_iterator iter;
5535 gcc_assert (cond != boolean_false_node);
5537 /* Propagate the RHS into every use of the LHS. */
5538 var = ASSERT_EXPR_VAR (rhs);
5539 FOR_EACH_IMM_USE_STMT (use_stmt, iter,
5540 gimple_assign_lhs (stmt))
5541 FOR_EACH_IMM_USE_ON_STMT (use_p, iter)
5543 SET_USE (use_p, var);
5544 gcc_assert (TREE_CODE (var) == SSA_NAME);
5547 /* And finally, remove the copy, it is not needed. */
5548 gsi_remove (&si, true);
5549 release_defs (stmt);
5557 /* Return true if STMT is interesting for VRP. */
5560 stmt_interesting_for_vrp (gimple stmt)
5562 if (gimple_code (stmt) == GIMPLE_PHI
5563 && is_gimple_reg (gimple_phi_result (stmt))
5564 && (INTEGRAL_TYPE_P (TREE_TYPE (gimple_phi_result (stmt)))
5565 || POINTER_TYPE_P (TREE_TYPE (gimple_phi_result (stmt)))))
5567 else if (is_gimple_assign (stmt) || is_gimple_call (stmt))
5569 tree lhs = gimple_get_lhs (stmt);
5571 /* In general, assignments with virtual operands are not useful
5572 for deriving ranges, with the obvious exception of calls to
5573 builtin functions. */
5574 if (lhs && TREE_CODE (lhs) == SSA_NAME
5575 && (INTEGRAL_TYPE_P (TREE_TYPE (lhs))
5576 || POINTER_TYPE_P (TREE_TYPE (lhs)))
5577 && ((is_gimple_call (stmt)
5578 && gimple_call_fndecl (stmt) != NULL_TREE
5579 && DECL_IS_BUILTIN (gimple_call_fndecl (stmt)))
5580 || !gimple_vuse (stmt)))
5583 else if (gimple_code (stmt) == GIMPLE_COND
5584 || gimple_code (stmt) == GIMPLE_SWITCH)
5591 /* Initialize local data structures for VRP. */
5594 vrp_initialize (void)
5598 values_propagated = false;
5599 num_vr_values = num_ssa_names;
5600 vr_value = XCNEWVEC (value_range_t *, num_vr_values);
5601 vr_phi_edge_counts = XCNEWVEC (int, num_ssa_names);
5605 gimple_stmt_iterator si;
5607 for (si = gsi_start_phis (bb); !gsi_end_p (si); gsi_next (&si))
5609 gimple phi = gsi_stmt (si);
5610 if (!stmt_interesting_for_vrp (phi))
5612 tree lhs = PHI_RESULT (phi);
5613 set_value_range_to_varying (get_value_range (lhs));
5614 prop_set_simulate_again (phi, false);
5617 prop_set_simulate_again (phi, true);
5620 for (si = gsi_start_bb (bb); !gsi_end_p (si); gsi_next (&si))
5622 gimple stmt = gsi_stmt (si);
5624 /* If the statement is a control insn, then we do not
5625 want to avoid simulating the statement once. Failure
5626 to do so means that those edges will never get added. */
5627 if (stmt_ends_bb_p (stmt))
5628 prop_set_simulate_again (stmt, true);
5629 else if (!stmt_interesting_for_vrp (stmt))
5633 FOR_EACH_SSA_TREE_OPERAND (def, stmt, i, SSA_OP_DEF)
5634 set_value_range_to_varying (get_value_range (def));
5635 prop_set_simulate_again (stmt, false);
5638 prop_set_simulate_again (stmt, true);
5643 /* Return the singleton value-range for NAME or NAME. */
5646 vrp_valueize (tree name)
5648 if (TREE_CODE (name) == SSA_NAME)
5650 value_range_t *vr = get_value_range (name);
5651 if (vr->type == VR_RANGE
5652 && (vr->min == vr->max
5653 || operand_equal_p (vr->min, vr->max, 0)))
5659 /* Visit assignment STMT. If it produces an interesting range, record
5660 the SSA name in *OUTPUT_P. */
5662 static enum ssa_prop_result
5663 vrp_visit_assignment_or_call (gimple stmt, tree *output_p)
5667 enum gimple_code code = gimple_code (stmt);
5668 lhs = gimple_get_lhs (stmt);
5670 /* We only keep track of ranges in integral and pointer types. */
5671 if (TREE_CODE (lhs) == SSA_NAME
5672 && ((INTEGRAL_TYPE_P (TREE_TYPE (lhs))
5673 /* It is valid to have NULL MIN/MAX values on a type. See
5674 build_range_type. */
5675 && TYPE_MIN_VALUE (TREE_TYPE (lhs))
5676 && TYPE_MAX_VALUE (TREE_TYPE (lhs)))
5677 || POINTER_TYPE_P (TREE_TYPE (lhs))))
5679 value_range_t new_vr = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
5681 /* Try folding the statement to a constant first. */
5682 tree tem = gimple_fold_stmt_to_constant (stmt, vrp_valueize);
5683 if (tem && !is_overflow_infinity (tem))
5684 set_value_range (&new_vr, VR_RANGE, tem, tem, NULL);
5685 /* Then dispatch to value-range extracting functions. */
5686 else if (code == GIMPLE_CALL)
5687 extract_range_basic (&new_vr, stmt);
5689 extract_range_from_assignment (&new_vr, stmt);
5691 if (update_value_range (lhs, &new_vr))
5695 if (dump_file && (dump_flags & TDF_DETAILS))
5697 fprintf (dump_file, "Found new range for ");
5698 print_generic_expr (dump_file, lhs, 0);
5699 fprintf (dump_file, ": ");
5700 dump_value_range (dump_file, &new_vr);
5701 fprintf (dump_file, "\n\n");
5704 if (new_vr.type == VR_VARYING)
5705 return SSA_PROP_VARYING;
5707 return SSA_PROP_INTERESTING;
5710 return SSA_PROP_NOT_INTERESTING;
5713 /* Every other statement produces no useful ranges. */
5714 FOR_EACH_SSA_TREE_OPERAND (def, stmt, iter, SSA_OP_DEF)
5715 set_value_range_to_varying (get_value_range (def));
5717 return SSA_PROP_VARYING;
5720 /* Helper that gets the value range of the SSA_NAME with version I
5721 or a symbolic range containing the SSA_NAME only if the value range
5722 is varying or undefined. */
5724 static inline value_range_t
5725 get_vr_for_comparison (int i)
5727 value_range_t vr = *get_value_range (ssa_name (i));
5729 /* If name N_i does not have a valid range, use N_i as its own
5730 range. This allows us to compare against names that may
5731 have N_i in their ranges. */
5732 if (vr.type == VR_VARYING || vr.type == VR_UNDEFINED)
5735 vr.min = ssa_name (i);
5736 vr.max = ssa_name (i);
5742 /* Compare all the value ranges for names equivalent to VAR with VAL
5743 using comparison code COMP. Return the same value returned by
5744 compare_range_with_value, including the setting of
5745 *STRICT_OVERFLOW_P. */
5748 compare_name_with_value (enum tree_code comp, tree var, tree val,
5749 bool *strict_overflow_p)
5755 int used_strict_overflow;
5757 value_range_t equiv_vr;
5759 /* Get the set of equivalences for VAR. */
5760 e = get_value_range (var)->equiv;
5762 /* Start at -1. Set it to 0 if we do a comparison without relying
5763 on overflow, or 1 if all comparisons rely on overflow. */
5764 used_strict_overflow = -1;
5766 /* Compare vars' value range with val. */
5767 equiv_vr = get_vr_for_comparison (SSA_NAME_VERSION (var));
5769 retval = compare_range_with_value (comp, &equiv_vr, val, &sop);
5771 used_strict_overflow = sop ? 1 : 0;
5773 /* If the equiv set is empty we have done all work we need to do. */
5777 && used_strict_overflow > 0)
5778 *strict_overflow_p = true;
5782 EXECUTE_IF_SET_IN_BITMAP (e, 0, i, bi)
5784 equiv_vr = get_vr_for_comparison (i);
5786 t = compare_range_with_value (comp, &equiv_vr, val, &sop);
5789 /* If we get different answers from different members
5790 of the equivalence set this check must be in a dead
5791 code region. Folding it to a trap representation
5792 would be correct here. For now just return don't-know. */
5802 used_strict_overflow = 0;
5803 else if (used_strict_overflow < 0)
5804 used_strict_overflow = 1;
5809 && used_strict_overflow > 0)
5810 *strict_overflow_p = true;
5816 /* Given a comparison code COMP and names N1 and N2, compare all the
5817 ranges equivalent to N1 against all the ranges equivalent to N2
5818 to determine the value of N1 COMP N2. Return the same value
5819 returned by compare_ranges. Set *STRICT_OVERFLOW_P to indicate
5820 whether we relied on an overflow infinity in the comparison. */
5824 compare_names (enum tree_code comp, tree n1, tree n2,
5825 bool *strict_overflow_p)
5829 bitmap_iterator bi1, bi2;
5831 int used_strict_overflow;
5832 static bitmap_obstack *s_obstack = NULL;
5833 static bitmap s_e1 = NULL, s_e2 = NULL;
5835 /* Compare the ranges of every name equivalent to N1 against the
5836 ranges of every name equivalent to N2. */
5837 e1 = get_value_range (n1)->equiv;
5838 e2 = get_value_range (n2)->equiv;
5840 /* Use the fake bitmaps if e1 or e2 are not available. */
5841 if (s_obstack == NULL)
5843 s_obstack = XNEW (bitmap_obstack);
5844 bitmap_obstack_initialize (s_obstack);
5845 s_e1 = BITMAP_ALLOC (s_obstack);
5846 s_e2 = BITMAP_ALLOC (s_obstack);
5853 /* Add N1 and N2 to their own set of equivalences to avoid
5854 duplicating the body of the loop just to check N1 and N2
5856 bitmap_set_bit (e1, SSA_NAME_VERSION (n1));
5857 bitmap_set_bit (e2, SSA_NAME_VERSION (n2));
5859 /* If the equivalence sets have a common intersection, then the two
5860 names can be compared without checking their ranges. */
5861 if (bitmap_intersect_p (e1, e2))
5863 bitmap_clear_bit (e1, SSA_NAME_VERSION (n1));
5864 bitmap_clear_bit (e2, SSA_NAME_VERSION (n2));
5866 return (comp == EQ_EXPR || comp == GE_EXPR || comp == LE_EXPR)
5868 : boolean_false_node;
5871 /* Start at -1. Set it to 0 if we do a comparison without relying
5872 on overflow, or 1 if all comparisons rely on overflow. */
5873 used_strict_overflow = -1;
5875 /* Otherwise, compare all the equivalent ranges. First, add N1 and
5876 N2 to their own set of equivalences to avoid duplicating the body
5877 of the loop just to check N1 and N2 ranges. */
5878 EXECUTE_IF_SET_IN_BITMAP (e1, 0, i1, bi1)
5880 value_range_t vr1 = get_vr_for_comparison (i1);
5882 t = retval = NULL_TREE;
5883 EXECUTE_IF_SET_IN_BITMAP (e2, 0, i2, bi2)
5887 value_range_t vr2 = get_vr_for_comparison (i2);
5889 t = compare_ranges (comp, &vr1, &vr2, &sop);
5892 /* If we get different answers from different members
5893 of the equivalence set this check must be in a dead
5894 code region. Folding it to a trap representation
5895 would be correct here. For now just return don't-know. */
5899 bitmap_clear_bit (e1, SSA_NAME_VERSION (n1));
5900 bitmap_clear_bit (e2, SSA_NAME_VERSION (n2));
5906 used_strict_overflow = 0;
5907 else if (used_strict_overflow < 0)
5908 used_strict_overflow = 1;
5914 bitmap_clear_bit (e1, SSA_NAME_VERSION (n1));
5915 bitmap_clear_bit (e2, SSA_NAME_VERSION (n2));
5916 if (used_strict_overflow > 0)
5917 *strict_overflow_p = true;
5922 /* None of the equivalent ranges are useful in computing this
5924 bitmap_clear_bit (e1, SSA_NAME_VERSION (n1));
5925 bitmap_clear_bit (e2, SSA_NAME_VERSION (n2));
5929 /* Helper function for vrp_evaluate_conditional_warnv. */
5932 vrp_evaluate_conditional_warnv_with_ops_using_ranges (enum tree_code code,
5934 bool * strict_overflow_p)
5936 value_range_t *vr0, *vr1;
5938 vr0 = (TREE_CODE (op0) == SSA_NAME) ? get_value_range (op0) : NULL;
5939 vr1 = (TREE_CODE (op1) == SSA_NAME) ? get_value_range (op1) : NULL;
5942 return compare_ranges (code, vr0, vr1, strict_overflow_p);
5943 else if (vr0 && vr1 == NULL)
5944 return compare_range_with_value (code, vr0, op1, strict_overflow_p);
5945 else if (vr0 == NULL && vr1)
5946 return (compare_range_with_value
5947 (swap_tree_comparison (code), vr1, op0, strict_overflow_p));
5951 /* Helper function for vrp_evaluate_conditional_warnv. */
5954 vrp_evaluate_conditional_warnv_with_ops (enum tree_code code, tree op0,
5955 tree op1, bool use_equiv_p,
5956 bool *strict_overflow_p, bool *only_ranges)
5960 *only_ranges = true;
5962 /* We only deal with integral and pointer types. */
5963 if (!INTEGRAL_TYPE_P (TREE_TYPE (op0))
5964 && !POINTER_TYPE_P (TREE_TYPE (op0)))
5970 && (ret = vrp_evaluate_conditional_warnv_with_ops_using_ranges
5971 (code, op0, op1, strict_overflow_p)))
5973 *only_ranges = false;
5974 if (TREE_CODE (op0) == SSA_NAME && TREE_CODE (op1) == SSA_NAME)
5975 return compare_names (code, op0, op1, strict_overflow_p);
5976 else if (TREE_CODE (op0) == SSA_NAME)
5977 return compare_name_with_value (code, op0, op1, strict_overflow_p);
5978 else if (TREE_CODE (op1) == SSA_NAME)
5979 return (compare_name_with_value
5980 (swap_tree_comparison (code), op1, op0, strict_overflow_p));
5983 return vrp_evaluate_conditional_warnv_with_ops_using_ranges (code, op0, op1,
5988 /* Given (CODE OP0 OP1) within STMT, try to simplify it based on value range
5989 information. Return NULL if the conditional can not be evaluated.
5990 The ranges of all the names equivalent with the operands in COND
5991 will be used when trying to compute the value. If the result is
5992 based on undefined signed overflow, issue a warning if
5996 vrp_evaluate_conditional (enum tree_code code, tree op0, tree op1, gimple stmt)
6002 /* Some passes and foldings leak constants with overflow flag set
6003 into the IL. Avoid doing wrong things with these and bail out. */
6004 if ((TREE_CODE (op0) == INTEGER_CST
6005 && TREE_OVERFLOW (op0))
6006 || (TREE_CODE (op1) == INTEGER_CST
6007 && TREE_OVERFLOW (op1)))
6011 ret = vrp_evaluate_conditional_warnv_with_ops (code, op0, op1, true, &sop,
6016 enum warn_strict_overflow_code wc;
6017 const char* warnmsg;
6019 if (is_gimple_min_invariant (ret))
6021 wc = WARN_STRICT_OVERFLOW_CONDITIONAL;
6022 warnmsg = G_("assuming signed overflow does not occur when "
6023 "simplifying conditional to constant");
6027 wc = WARN_STRICT_OVERFLOW_COMPARISON;
6028 warnmsg = G_("assuming signed overflow does not occur when "
6029 "simplifying conditional");
6032 if (issue_strict_overflow_warning (wc))
6034 location_t location;
6036 if (!gimple_has_location (stmt))
6037 location = input_location;
6039 location = gimple_location (stmt);
6040 warning_at (location, OPT_Wstrict_overflow, "%s", warnmsg);
6044 if (warn_type_limits
6045 && ret && only_ranges
6046 && TREE_CODE_CLASS (code) == tcc_comparison
6047 && TREE_CODE (op0) == SSA_NAME)
6049 /* If the comparison is being folded and the operand on the LHS
6050 is being compared against a constant value that is outside of
6051 the natural range of OP0's type, then the predicate will
6052 always fold regardless of the value of OP0. If -Wtype-limits
6053 was specified, emit a warning. */
6054 tree type = TREE_TYPE (op0);
6055 value_range_t *vr0 = get_value_range (op0);
6057 if (vr0->type != VR_VARYING
6058 && INTEGRAL_TYPE_P (type)
6059 && vrp_val_is_min (vr0->min)
6060 && vrp_val_is_max (vr0->max)
6061 && is_gimple_min_invariant (op1))
6063 location_t location;
6065 if (!gimple_has_location (stmt))
6066 location = input_location;
6068 location = gimple_location (stmt);
6070 warning_at (location, OPT_Wtype_limits,
6072 ? G_("comparison always false "
6073 "due to limited range of data type")
6074 : G_("comparison always true "
6075 "due to limited range of data type"));
6083 /* Visit conditional statement STMT. If we can determine which edge
6084 will be taken out of STMT's basic block, record it in
6085 *TAKEN_EDGE_P and return SSA_PROP_INTERESTING. Otherwise, return
6086 SSA_PROP_VARYING. */
6088 static enum ssa_prop_result
6089 vrp_visit_cond_stmt (gimple stmt, edge *taken_edge_p)
6094 *taken_edge_p = NULL;
6096 if (dump_file && (dump_flags & TDF_DETAILS))
6101 fprintf (dump_file, "\nVisiting conditional with predicate: ");
6102 print_gimple_stmt (dump_file, stmt, 0, 0);
6103 fprintf (dump_file, "\nWith known ranges\n");
6105 FOR_EACH_SSA_TREE_OPERAND (use, stmt, i, SSA_OP_USE)
6107 fprintf (dump_file, "\t");
6108 print_generic_expr (dump_file, use, 0);
6109 fprintf (dump_file, ": ");
6110 dump_value_range (dump_file, vr_value[SSA_NAME_VERSION (use)]);
6113 fprintf (dump_file, "\n");
6116 /* Compute the value of the predicate COND by checking the known
6117 ranges of each of its operands.
6119 Note that we cannot evaluate all the equivalent ranges here
6120 because those ranges may not yet be final and with the current
6121 propagation strategy, we cannot determine when the value ranges
6122 of the names in the equivalence set have changed.
6124 For instance, given the following code fragment
6128 i_14 = ASSERT_EXPR <i_5, i_5 != 0>
6132 Assume that on the first visit to i_14, i_5 has the temporary
6133 range [8, 8] because the second argument to the PHI function is
6134 not yet executable. We derive the range ~[0, 0] for i_14 and the
6135 equivalence set { i_5 }. So, when we visit 'if (i_14 == 1)' for
6136 the first time, since i_14 is equivalent to the range [8, 8], we
6137 determine that the predicate is always false.
6139 On the next round of propagation, i_13 is determined to be
6140 VARYING, which causes i_5 to drop down to VARYING. So, another
6141 visit to i_14 is scheduled. In this second visit, we compute the
6142 exact same range and equivalence set for i_14, namely ~[0, 0] and
6143 { i_5 }. But we did not have the previous range for i_5
6144 registered, so vrp_visit_assignment thinks that the range for
6145 i_14 has not changed. Therefore, the predicate 'if (i_14 == 1)'
6146 is not visited again, which stops propagation from visiting
6147 statements in the THEN clause of that if().
6149 To properly fix this we would need to keep the previous range
6150 value for the names in the equivalence set. This way we would've
6151 discovered that from one visit to the other i_5 changed from
6152 range [8, 8] to VR_VARYING.
6154 However, fixing this apparent limitation may not be worth the
6155 additional checking. Testing on several code bases (GCC, DLV,
6156 MICO, TRAMP3D and SPEC2000) showed that doing this results in
6157 4 more predicates folded in SPEC. */
6160 val = vrp_evaluate_conditional_warnv_with_ops (gimple_cond_code (stmt),
6161 gimple_cond_lhs (stmt),
6162 gimple_cond_rhs (stmt),
6167 *taken_edge_p = find_taken_edge (gimple_bb (stmt), val);
6170 if (dump_file && (dump_flags & TDF_DETAILS))
6172 "\nIgnoring predicate evaluation because "
6173 "it assumes that signed overflow is undefined");
6178 if (dump_file && (dump_flags & TDF_DETAILS))
6180 fprintf (dump_file, "\nPredicate evaluates to: ");
6181 if (val == NULL_TREE)
6182 fprintf (dump_file, "DON'T KNOW\n");
6184 print_generic_stmt (dump_file, val, 0);
6187 return (*taken_edge_p) ? SSA_PROP_INTERESTING : SSA_PROP_VARYING;
6190 /* Searches the case label vector VEC for the index *IDX of the CASE_LABEL
6191 that includes the value VAL. The search is restricted to the range
6192 [START_IDX, n - 1] where n is the size of VEC.
6194 If there is a CASE_LABEL for VAL, its index is placed in IDX and true is
6197 If there is no CASE_LABEL for VAL and there is one that is larger than VAL,
6198 it is placed in IDX and false is returned.
6200 If VAL is larger than any CASE_LABEL, n is placed on IDX and false is
6204 find_case_label_index (gimple stmt, size_t start_idx, tree val, size_t *idx)
6206 size_t n = gimple_switch_num_labels (stmt);
6209 /* Find case label for minimum of the value range or the next one.
6210 At each iteration we are searching in [low, high - 1]. */
6212 for (low = start_idx, high = n; high != low; )
6216 /* Note that i != high, so we never ask for n. */
6217 size_t i = (high + low) / 2;
6218 t = gimple_switch_label (stmt, i);
6220 /* Cache the result of comparing CASE_LOW and val. */
6221 cmp = tree_int_cst_compare (CASE_LOW (t), val);
6225 /* Ranges cannot be empty. */
6234 if (CASE_HIGH (t) != NULL
6235 && tree_int_cst_compare (CASE_HIGH (t), val) >= 0)
6247 /* Searches the case label vector VEC for the range of CASE_LABELs that is used
6248 for values between MIN and MAX. The first index is placed in MIN_IDX. The
6249 last index is placed in MAX_IDX. If the range of CASE_LABELs is empty
6250 then MAX_IDX < MIN_IDX.
6251 Returns true if the default label is not needed. */
6254 find_case_label_range (gimple stmt, tree min, tree max, size_t *min_idx,
6258 bool min_take_default = !find_case_label_index (stmt, 1, min, &i);
6259 bool max_take_default = !find_case_label_index (stmt, i, max, &j);
6263 && max_take_default)
6265 /* Only the default case label reached.
6266 Return an empty range. */
6273 bool take_default = min_take_default || max_take_default;
6277 if (max_take_default)
6280 /* If the case label range is continuous, we do not need
6281 the default case label. Verify that. */
6282 high = CASE_LOW (gimple_switch_label (stmt, i));
6283 if (CASE_HIGH (gimple_switch_label (stmt, i)))
6284 high = CASE_HIGH (gimple_switch_label (stmt, i));
6285 for (k = i + 1; k <= j; ++k)
6287 low = CASE_LOW (gimple_switch_label (stmt, k));
6288 if (!integer_onep (int_const_binop (MINUS_EXPR, low, high)))
6290 take_default = true;
6294 if (CASE_HIGH (gimple_switch_label (stmt, k)))
6295 high = CASE_HIGH (gimple_switch_label (stmt, k));
6300 return !take_default;
6304 /* Visit switch statement STMT. If we can determine which edge
6305 will be taken out of STMT's basic block, record it in
6306 *TAKEN_EDGE_P and return SSA_PROP_INTERESTING. Otherwise, return
6307 SSA_PROP_VARYING. */
6309 static enum ssa_prop_result
6310 vrp_visit_switch_stmt (gimple stmt, edge *taken_edge_p)
6314 size_t i = 0, j = 0;
6317 *taken_edge_p = NULL;
6318 op = gimple_switch_index (stmt);
6319 if (TREE_CODE (op) != SSA_NAME)
6320 return SSA_PROP_VARYING;
6322 vr = get_value_range (op);
6323 if (dump_file && (dump_flags & TDF_DETAILS))
6325 fprintf (dump_file, "\nVisiting switch expression with operand ");
6326 print_generic_expr (dump_file, op, 0);
6327 fprintf (dump_file, " with known range ");
6328 dump_value_range (dump_file, vr);
6329 fprintf (dump_file, "\n");
6332 if (vr->type != VR_RANGE
6333 || symbolic_range_p (vr))
6334 return SSA_PROP_VARYING;
6336 /* Find the single edge that is taken from the switch expression. */
6337 take_default = !find_case_label_range (stmt, vr->min, vr->max, &i, &j);
6339 /* Check if the range spans no CASE_LABEL. If so, we only reach the default
6343 gcc_assert (take_default);
6344 val = gimple_switch_default_label (stmt);
6348 /* Check if labels with index i to j and maybe the default label
6349 are all reaching the same label. */
6351 val = gimple_switch_label (stmt, i);
6353 && CASE_LABEL (gimple_switch_default_label (stmt))
6354 != CASE_LABEL (val))
6356 if (dump_file && (dump_flags & TDF_DETAILS))
6357 fprintf (dump_file, " not a single destination for this "
6359 return SSA_PROP_VARYING;
6361 for (++i; i <= j; ++i)
6363 if (CASE_LABEL (gimple_switch_label (stmt, i)) != CASE_LABEL (val))
6365 if (dump_file && (dump_flags & TDF_DETAILS))
6366 fprintf (dump_file, " not a single destination for this "
6368 return SSA_PROP_VARYING;
6373 *taken_edge_p = find_edge (gimple_bb (stmt),
6374 label_to_block (CASE_LABEL (val)));
6376 if (dump_file && (dump_flags & TDF_DETAILS))
6378 fprintf (dump_file, " will take edge to ");
6379 print_generic_stmt (dump_file, CASE_LABEL (val), 0);
6382 return SSA_PROP_INTERESTING;
6386 /* Evaluate statement STMT. If the statement produces a useful range,
6387 return SSA_PROP_INTERESTING and record the SSA name with the
6388 interesting range into *OUTPUT_P.
6390 If STMT is a conditional branch and we can determine its truth
6391 value, the taken edge is recorded in *TAKEN_EDGE_P.
6393 If STMT produces a varying value, return SSA_PROP_VARYING. */
6395 static enum ssa_prop_result
6396 vrp_visit_stmt (gimple stmt, edge *taken_edge_p, tree *output_p)
6401 if (dump_file && (dump_flags & TDF_DETAILS))
6403 fprintf (dump_file, "\nVisiting statement:\n");
6404 print_gimple_stmt (dump_file, stmt, 0, dump_flags);
6405 fprintf (dump_file, "\n");
6408 if (!stmt_interesting_for_vrp (stmt))
6409 gcc_assert (stmt_ends_bb_p (stmt));
6410 else if (is_gimple_assign (stmt) || is_gimple_call (stmt))
6412 /* In general, assignments with virtual operands are not useful
6413 for deriving ranges, with the obvious exception of calls to
6414 builtin functions. */
6415 if ((is_gimple_call (stmt)
6416 && gimple_call_fndecl (stmt) != NULL_TREE
6417 && DECL_IS_BUILTIN (gimple_call_fndecl (stmt)))
6418 || !gimple_vuse (stmt))
6419 return vrp_visit_assignment_or_call (stmt, output_p);
6421 else if (gimple_code (stmt) == GIMPLE_COND)
6422 return vrp_visit_cond_stmt (stmt, taken_edge_p);
6423 else if (gimple_code (stmt) == GIMPLE_SWITCH)
6424 return vrp_visit_switch_stmt (stmt, taken_edge_p);
6426 /* All other statements produce nothing of interest for VRP, so mark
6427 their outputs varying and prevent further simulation. */
6428 FOR_EACH_SSA_TREE_OPERAND (def, stmt, iter, SSA_OP_DEF)
6429 set_value_range_to_varying (get_value_range (def));
6431 return SSA_PROP_VARYING;
6435 /* Meet operation for value ranges. Given two value ranges VR0 and
6436 VR1, store in VR0 a range that contains both VR0 and VR1. This
6437 may not be the smallest possible such range. */
6440 vrp_meet (value_range_t *vr0, value_range_t *vr1)
6442 if (vr0->type == VR_UNDEFINED)
6444 copy_value_range (vr0, vr1);
6448 if (vr1->type == VR_UNDEFINED)
6450 /* Nothing to do. VR0 already has the resulting range. */
6454 if (vr0->type == VR_VARYING)
6456 /* Nothing to do. VR0 already has the resulting range. */
6460 if (vr1->type == VR_VARYING)
6462 set_value_range_to_varying (vr0);
6466 if (vr0->type == VR_RANGE && vr1->type == VR_RANGE)
6471 /* Compute the convex hull of the ranges. The lower limit of
6472 the new range is the minimum of the two ranges. If they
6473 cannot be compared, then give up. */
6474 cmp = compare_values (vr0->min, vr1->min);
6475 if (cmp == 0 || cmp == 1)
6482 /* Similarly, the upper limit of the new range is the maximum
6483 of the two ranges. If they cannot be compared, then
6485 cmp = compare_values (vr0->max, vr1->max);
6486 if (cmp == 0 || cmp == -1)
6493 /* Check for useless ranges. */
6494 if (INTEGRAL_TYPE_P (TREE_TYPE (min))
6495 && ((vrp_val_is_min (min) || is_overflow_infinity (min))
6496 && (vrp_val_is_max (max) || is_overflow_infinity (max))))
6499 /* The resulting set of equivalences is the intersection of
6501 if (vr0->equiv && vr1->equiv && vr0->equiv != vr1->equiv)
6502 bitmap_and_into (vr0->equiv, vr1->equiv);
6503 else if (vr0->equiv && !vr1->equiv)
6504 bitmap_clear (vr0->equiv);
6506 set_value_range (vr0, vr0->type, min, max, vr0->equiv);
6508 else if (vr0->type == VR_ANTI_RANGE && vr1->type == VR_ANTI_RANGE)
6510 /* Two anti-ranges meet only if their complements intersect.
6511 Only handle the case of identical ranges. */
6512 if (compare_values (vr0->min, vr1->min) == 0
6513 && compare_values (vr0->max, vr1->max) == 0
6514 && compare_values (vr0->min, vr0->max) == 0)
6516 /* The resulting set of equivalences is the intersection of
6518 if (vr0->equiv && vr1->equiv && vr0->equiv != vr1->equiv)
6519 bitmap_and_into (vr0->equiv, vr1->equiv);
6520 else if (vr0->equiv && !vr1->equiv)
6521 bitmap_clear (vr0->equiv);
6526 else if (vr0->type == VR_ANTI_RANGE || vr1->type == VR_ANTI_RANGE)
6528 /* For a numeric range [VAL1, VAL2] and an anti-range ~[VAL3, VAL4],
6529 only handle the case where the ranges have an empty intersection.
6530 The result of the meet operation is the anti-range. */
6531 if (!symbolic_range_p (vr0)
6532 && !symbolic_range_p (vr1)
6533 && !value_ranges_intersect_p (vr0, vr1))
6535 /* Copy most of VR1 into VR0. Don't copy VR1's equivalence
6536 set. We need to compute the intersection of the two
6537 equivalence sets. */
6538 if (vr1->type == VR_ANTI_RANGE)
6539 set_value_range (vr0, vr1->type, vr1->min, vr1->max, vr0->equiv);
6541 /* The resulting set of equivalences is the intersection of
6543 if (vr0->equiv && vr1->equiv && vr0->equiv != vr1->equiv)
6544 bitmap_and_into (vr0->equiv, vr1->equiv);
6545 else if (vr0->equiv && !vr1->equiv)
6546 bitmap_clear (vr0->equiv);
6557 /* Failed to find an efficient meet. Before giving up and setting
6558 the result to VARYING, see if we can at least derive a useful
6559 anti-range. FIXME, all this nonsense about distinguishing
6560 anti-ranges from ranges is necessary because of the odd
6561 semantics of range_includes_zero_p and friends. */
6562 if (!symbolic_range_p (vr0)
6563 && ((vr0->type == VR_RANGE && !range_includes_zero_p (vr0))
6564 || (vr0->type == VR_ANTI_RANGE && range_includes_zero_p (vr0)))
6565 && !symbolic_range_p (vr1)
6566 && ((vr1->type == VR_RANGE && !range_includes_zero_p (vr1))
6567 || (vr1->type == VR_ANTI_RANGE && range_includes_zero_p (vr1))))
6569 set_value_range_to_nonnull (vr0, TREE_TYPE (vr0->min));
6571 /* Since this meet operation did not result from the meeting of
6572 two equivalent names, VR0 cannot have any equivalences. */
6574 bitmap_clear (vr0->equiv);
6577 set_value_range_to_varying (vr0);
6581 /* Visit all arguments for PHI node PHI that flow through executable
6582 edges. If a valid value range can be derived from all the incoming
6583 value ranges, set a new range for the LHS of PHI. */
6585 static enum ssa_prop_result
6586 vrp_visit_phi_node (gimple phi)
6589 tree lhs = PHI_RESULT (phi);
6590 value_range_t *lhs_vr = get_value_range (lhs);
6591 value_range_t vr_result = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
6592 int edges, old_edges;
6595 if (dump_file && (dump_flags & TDF_DETAILS))
6597 fprintf (dump_file, "\nVisiting PHI node: ");
6598 print_gimple_stmt (dump_file, phi, 0, dump_flags);
6602 for (i = 0; i < gimple_phi_num_args (phi); i++)
6604 edge e = gimple_phi_arg_edge (phi, i);
6606 if (dump_file && (dump_flags & TDF_DETAILS))
6609 "\n Argument #%d (%d -> %d %sexecutable)\n",
6610 (int) i, e->src->index, e->dest->index,
6611 (e->flags & EDGE_EXECUTABLE) ? "" : "not ");
6614 if (e->flags & EDGE_EXECUTABLE)
6616 tree arg = PHI_ARG_DEF (phi, i);
6617 value_range_t vr_arg;
6621 if (TREE_CODE (arg) == SSA_NAME)
6623 vr_arg = *(get_value_range (arg));
6627 if (is_overflow_infinity (arg))
6629 arg = copy_node (arg);
6630 TREE_OVERFLOW (arg) = 0;
6633 vr_arg.type = VR_RANGE;
6636 vr_arg.equiv = NULL;
6639 if (dump_file && (dump_flags & TDF_DETAILS))
6641 fprintf (dump_file, "\t");
6642 print_generic_expr (dump_file, arg, dump_flags);
6643 fprintf (dump_file, "\n\tValue: ");
6644 dump_value_range (dump_file, &vr_arg);
6645 fprintf (dump_file, "\n");
6648 vrp_meet (&vr_result, &vr_arg);
6650 if (vr_result.type == VR_VARYING)
6655 if (vr_result.type == VR_VARYING)
6657 else if (vr_result.type == VR_UNDEFINED)
6660 old_edges = vr_phi_edge_counts[SSA_NAME_VERSION (lhs)];
6661 vr_phi_edge_counts[SSA_NAME_VERSION (lhs)] = edges;
6663 /* To prevent infinite iterations in the algorithm, derive ranges
6664 when the new value is slightly bigger or smaller than the
6665 previous one. We don't do this if we have seen a new executable
6666 edge; this helps us avoid an overflow infinity for conditionals
6667 which are not in a loop. */
6669 && gimple_phi_num_args (phi) > 1
6670 && edges == old_edges)
6672 int cmp_min = compare_values (lhs_vr->min, vr_result.min);
6673 int cmp_max = compare_values (lhs_vr->max, vr_result.max);
6675 /* For non VR_RANGE or for pointers fall back to varying if
6676 the range changed. */
6677 if ((lhs_vr->type != VR_RANGE || vr_result.type != VR_RANGE
6678 || POINTER_TYPE_P (TREE_TYPE (lhs)))
6679 && (cmp_min != 0 || cmp_max != 0))
6682 /* If the new minimum is smaller or larger than the previous
6683 one, go all the way to -INF. In the first case, to avoid
6684 iterating millions of times to reach -INF, and in the
6685 other case to avoid infinite bouncing between different
6687 if (cmp_min > 0 || cmp_min < 0)
6689 if (!needs_overflow_infinity (TREE_TYPE (vr_result.min))
6690 || !vrp_var_may_overflow (lhs, phi))
6691 vr_result.min = TYPE_MIN_VALUE (TREE_TYPE (vr_result.min));
6692 else if (supports_overflow_infinity (TREE_TYPE (vr_result.min)))
6694 negative_overflow_infinity (TREE_TYPE (vr_result.min));
6697 /* Similarly, if the new maximum is smaller or larger than
6698 the previous one, go all the way to +INF. */
6699 if (cmp_max < 0 || cmp_max > 0)
6701 if (!needs_overflow_infinity (TREE_TYPE (vr_result.max))
6702 || !vrp_var_may_overflow (lhs, phi))
6703 vr_result.max = TYPE_MAX_VALUE (TREE_TYPE (vr_result.max));
6704 else if (supports_overflow_infinity (TREE_TYPE (vr_result.max)))
6706 positive_overflow_infinity (TREE_TYPE (vr_result.max));
6709 /* If we dropped either bound to +-INF then if this is a loop
6710 PHI node SCEV may known more about its value-range. */
6711 if ((cmp_min > 0 || cmp_min < 0
6712 || cmp_max < 0 || cmp_max > 0)
6714 && (l = loop_containing_stmt (phi))
6715 && l->header == gimple_bb (phi))
6716 adjust_range_with_scev (&vr_result, l, phi, lhs);
6718 /* If we will end up with a (-INF, +INF) range, set it to
6719 VARYING. Same if the previous max value was invalid for
6720 the type and we end up with vr_result.min > vr_result.max. */
6721 if ((vrp_val_is_max (vr_result.max)
6722 && vrp_val_is_min (vr_result.min))
6723 || compare_values (vr_result.min,
6728 /* If the new range is different than the previous value, keep
6731 if (update_value_range (lhs, &vr_result))
6733 if (dump_file && (dump_flags & TDF_DETAILS))
6735 fprintf (dump_file, "Found new range for ");
6736 print_generic_expr (dump_file, lhs, 0);
6737 fprintf (dump_file, ": ");
6738 dump_value_range (dump_file, &vr_result);
6739 fprintf (dump_file, "\n\n");
6742 return SSA_PROP_INTERESTING;
6745 /* Nothing changed, don't add outgoing edges. */
6746 return SSA_PROP_NOT_INTERESTING;
6748 /* No match found. Set the LHS to VARYING. */
6750 set_value_range_to_varying (lhs_vr);
6751 return SSA_PROP_VARYING;
6754 /* Simplify boolean operations if the source is known
6755 to be already a boolean. */
6757 simplify_truth_ops_using_ranges (gimple_stmt_iterator *gsi, gimple stmt)
6759 enum tree_code rhs_code = gimple_assign_rhs_code (stmt);
6761 bool need_conversion;
6763 /* We handle only !=/== case here. */
6764 gcc_assert (rhs_code == EQ_EXPR || rhs_code == NE_EXPR);
6766 op0 = gimple_assign_rhs1 (stmt);
6767 if (!op_with_boolean_value_range_p (op0))
6770 op1 = gimple_assign_rhs2 (stmt);
6771 if (!op_with_boolean_value_range_p (op1))
6774 /* Reduce number of cases to handle to NE_EXPR. As there is no
6775 BIT_XNOR_EXPR we cannot replace A == B with a single statement. */
6776 if (rhs_code == EQ_EXPR)
6778 if (TREE_CODE (op1) == INTEGER_CST)
6779 op1 = int_const_binop (BIT_XOR_EXPR, op1, integer_one_node);
6784 lhs = gimple_assign_lhs (stmt);
6786 = !useless_type_conversion_p (TREE_TYPE (lhs), TREE_TYPE (op0));
6788 /* Make sure to not sign-extend a 1-bit 1 when converting the result. */
6790 && !TYPE_UNSIGNED (TREE_TYPE (op0))
6791 && TYPE_PRECISION (TREE_TYPE (op0)) == 1
6792 && TYPE_PRECISION (TREE_TYPE (lhs)) > 1)
6795 /* For A != 0 we can substitute A itself. */
6796 if (integer_zerop (op1))
6797 gimple_assign_set_rhs_with_ops (gsi,
6799 ? NOP_EXPR : TREE_CODE (op0),
6801 /* For A != B we substitute A ^ B. Either with conversion. */
6802 else if (need_conversion)
6805 tree tem = create_tmp_reg (TREE_TYPE (op0), NULL);
6806 newop = gimple_build_assign_with_ops (BIT_XOR_EXPR, tem, op0, op1);
6807 tem = make_ssa_name (tem, newop);
6808 gimple_assign_set_lhs (newop, tem);
6809 gsi_insert_before (gsi, newop, GSI_SAME_STMT);
6810 update_stmt (newop);
6811 gimple_assign_set_rhs_with_ops (gsi, NOP_EXPR, tem, NULL_TREE);
6815 gimple_assign_set_rhs_with_ops (gsi, BIT_XOR_EXPR, op0, op1);
6816 update_stmt (gsi_stmt (*gsi));
6821 /* Simplify a division or modulo operator to a right shift or
6822 bitwise and if the first operand is unsigned or is greater
6823 than zero and the second operand is an exact power of two. */
6826 simplify_div_or_mod_using_ranges (gimple stmt)
6828 enum tree_code rhs_code = gimple_assign_rhs_code (stmt);
6830 tree op0 = gimple_assign_rhs1 (stmt);
6831 tree op1 = gimple_assign_rhs2 (stmt);
6832 value_range_t *vr = get_value_range (gimple_assign_rhs1 (stmt));
6834 if (TYPE_UNSIGNED (TREE_TYPE (op0)))
6836 val = integer_one_node;
6842 val = compare_range_with_value (GE_EXPR, vr, integer_zero_node, &sop);
6846 && integer_onep (val)
6847 && issue_strict_overflow_warning (WARN_STRICT_OVERFLOW_MISC))
6849 location_t location;
6851 if (!gimple_has_location (stmt))
6852 location = input_location;
6854 location = gimple_location (stmt);
6855 warning_at (location, OPT_Wstrict_overflow,
6856 "assuming signed overflow does not occur when "
6857 "simplifying %</%> or %<%%%> to %<>>%> or %<&%>");
6861 if (val && integer_onep (val))
6865 if (rhs_code == TRUNC_DIV_EXPR)
6867 t = build_int_cst (integer_type_node, tree_log2 (op1));
6868 gimple_assign_set_rhs_code (stmt, RSHIFT_EXPR);
6869 gimple_assign_set_rhs1 (stmt, op0);
6870 gimple_assign_set_rhs2 (stmt, t);
6874 t = build_int_cst (TREE_TYPE (op1), 1);
6875 t = int_const_binop (MINUS_EXPR, op1, t);
6876 t = fold_convert (TREE_TYPE (op0), t);
6878 gimple_assign_set_rhs_code (stmt, BIT_AND_EXPR);
6879 gimple_assign_set_rhs1 (stmt, op0);
6880 gimple_assign_set_rhs2 (stmt, t);
6890 /* If the operand to an ABS_EXPR is >= 0, then eliminate the
6891 ABS_EXPR. If the operand is <= 0, then simplify the
6892 ABS_EXPR into a NEGATE_EXPR. */
6895 simplify_abs_using_ranges (gimple stmt)
6898 tree op = gimple_assign_rhs1 (stmt);
6899 tree type = TREE_TYPE (op);
6900 value_range_t *vr = get_value_range (op);
6902 if (TYPE_UNSIGNED (type))
6904 val = integer_zero_node;
6910 val = compare_range_with_value (LE_EXPR, vr, integer_zero_node, &sop);
6914 val = compare_range_with_value (GE_EXPR, vr, integer_zero_node,
6919 if (integer_zerop (val))
6920 val = integer_one_node;
6921 else if (integer_onep (val))
6922 val = integer_zero_node;
6927 && (integer_onep (val) || integer_zerop (val)))
6929 if (sop && issue_strict_overflow_warning (WARN_STRICT_OVERFLOW_MISC))
6931 location_t location;
6933 if (!gimple_has_location (stmt))
6934 location = input_location;
6936 location = gimple_location (stmt);
6937 warning_at (location, OPT_Wstrict_overflow,
6938 "assuming signed overflow does not occur when "
6939 "simplifying %<abs (X)%> to %<X%> or %<-X%>");
6942 gimple_assign_set_rhs1 (stmt, op);
6943 if (integer_onep (val))
6944 gimple_assign_set_rhs_code (stmt, NEGATE_EXPR);
6946 gimple_assign_set_rhs_code (stmt, SSA_NAME);
6955 /* Optimize away redundant BIT_AND_EXPR and BIT_IOR_EXPR.
6956 If all the bits that are being cleared by & are already
6957 known to be zero from VR, or all the bits that are being
6958 set by | are already known to be one from VR, the bit
6959 operation is redundant. */
6962 simplify_bit_ops_using_ranges (gimple_stmt_iterator *gsi, gimple stmt)
6964 tree op0 = gimple_assign_rhs1 (stmt);
6965 tree op1 = gimple_assign_rhs2 (stmt);
6966 tree op = NULL_TREE;
6967 value_range_t vr0 = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
6968 value_range_t vr1 = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
6969 double_int may_be_nonzero0, may_be_nonzero1;
6970 double_int must_be_nonzero0, must_be_nonzero1;
6973 if (TREE_CODE (op0) == SSA_NAME)
6974 vr0 = *(get_value_range (op0));
6975 else if (is_gimple_min_invariant (op0))
6976 set_value_range_to_value (&vr0, op0, NULL);
6980 if (TREE_CODE (op1) == SSA_NAME)
6981 vr1 = *(get_value_range (op1));
6982 else if (is_gimple_min_invariant (op1))
6983 set_value_range_to_value (&vr1, op1, NULL);
6987 if (!zero_nonzero_bits_from_vr (&vr0, &may_be_nonzero0, &must_be_nonzero0))
6989 if (!zero_nonzero_bits_from_vr (&vr1, &may_be_nonzero1, &must_be_nonzero1))
6992 switch (gimple_assign_rhs_code (stmt))
6995 mask = double_int_and_not (may_be_nonzero0, must_be_nonzero1);
6996 if (double_int_zero_p (mask))
7001 mask = double_int_and_not (may_be_nonzero1, must_be_nonzero0);
7002 if (double_int_zero_p (mask))
7009 mask = double_int_and_not (may_be_nonzero0, must_be_nonzero1);
7010 if (double_int_zero_p (mask))
7015 mask = double_int_and_not (may_be_nonzero1, must_be_nonzero0);
7016 if (double_int_zero_p (mask))
7026 if (op == NULL_TREE)
7029 gimple_assign_set_rhs_with_ops (gsi, TREE_CODE (op), op, NULL);
7030 update_stmt (gsi_stmt (*gsi));
7034 /* We are comparing trees OP0 and OP1 using COND_CODE. OP0 has
7035 a known value range VR.
7037 If there is one and only one value which will satisfy the
7038 conditional, then return that value. Else return NULL. */
7041 test_for_singularity (enum tree_code cond_code, tree op0,
7042 tree op1, value_range_t *vr)
7047 /* Extract minimum/maximum values which satisfy the
7048 the conditional as it was written. */
7049 if (cond_code == LE_EXPR || cond_code == LT_EXPR)
7051 /* This should not be negative infinity; there is no overflow
7053 min = TYPE_MIN_VALUE (TREE_TYPE (op0));
7056 if (cond_code == LT_EXPR && !is_overflow_infinity (max))
7058 tree one = build_int_cst (TREE_TYPE (op0), 1);
7059 max = fold_build2 (MINUS_EXPR, TREE_TYPE (op0), max, one);
7061 TREE_NO_WARNING (max) = 1;
7064 else if (cond_code == GE_EXPR || cond_code == GT_EXPR)
7066 /* This should not be positive infinity; there is no overflow
7068 max = TYPE_MAX_VALUE (TREE_TYPE (op0));
7071 if (cond_code == GT_EXPR && !is_overflow_infinity (min))
7073 tree one = build_int_cst (TREE_TYPE (op0), 1);
7074 min = fold_build2 (PLUS_EXPR, TREE_TYPE (op0), min, one);
7076 TREE_NO_WARNING (min) = 1;
7080 /* Now refine the minimum and maximum values using any
7081 value range information we have for op0. */
7084 if (compare_values (vr->min, min) == 1)
7086 if (compare_values (vr->max, max) == -1)
7089 /* If the new min/max values have converged to a single value,
7090 then there is only one value which can satisfy the condition,
7091 return that value. */
7092 if (operand_equal_p (min, max, 0) && is_gimple_min_invariant (min))
7098 /* Simplify a conditional using a relational operator to an equality
7099 test if the range information indicates only one value can satisfy
7100 the original conditional. */
7103 simplify_cond_using_ranges (gimple stmt)
7105 tree op0 = gimple_cond_lhs (stmt);
7106 tree op1 = gimple_cond_rhs (stmt);
7107 enum tree_code cond_code = gimple_cond_code (stmt);
7109 if (cond_code != NE_EXPR
7110 && cond_code != EQ_EXPR
7111 && TREE_CODE (op0) == SSA_NAME
7112 && INTEGRAL_TYPE_P (TREE_TYPE (op0))
7113 && is_gimple_min_invariant (op1))
7115 value_range_t *vr = get_value_range (op0);
7117 /* If we have range information for OP0, then we might be
7118 able to simplify this conditional. */
7119 if (vr->type == VR_RANGE)
7121 tree 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, EQ_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");
7147 /* Try again after inverting the condition. We only deal
7148 with integral types here, so no need to worry about
7149 issues with inverting FP comparisons. */
7150 cond_code = invert_tree_comparison (cond_code, false);
7151 new_tree = test_for_singularity (cond_code, op0, op1, vr);
7157 fprintf (dump_file, "Simplified relational ");
7158 print_gimple_stmt (dump_file, stmt, 0, 0);
7159 fprintf (dump_file, " into ");
7162 gimple_cond_set_code (stmt, NE_EXPR);
7163 gimple_cond_set_lhs (stmt, op0);
7164 gimple_cond_set_rhs (stmt, new_tree);
7170 print_gimple_stmt (dump_file, stmt, 0, 0);
7171 fprintf (dump_file, "\n");
7182 /* Simplify a switch statement using the value range of the switch
7186 simplify_switch_using_ranges (gimple stmt)
7188 tree op = gimple_switch_index (stmt);
7193 size_t i = 0, j = 0, n, n2;
7197 if (TREE_CODE (op) == SSA_NAME)
7199 vr = get_value_range (op);
7201 /* We can only handle integer ranges. */
7202 if (vr->type != VR_RANGE
7203 || symbolic_range_p (vr))
7206 /* Find case label for min/max of the value range. */
7207 take_default = !find_case_label_range (stmt, vr->min, vr->max, &i, &j);
7209 else if (TREE_CODE (op) == INTEGER_CST)
7211 take_default = !find_case_label_index (stmt, 1, op, &i);
7225 n = gimple_switch_num_labels (stmt);
7227 /* Bail out if this is just all edges taken. */
7233 /* Build a new vector of taken case labels. */
7234 vec2 = make_tree_vec (j - i + 1 + (int)take_default);
7237 /* Add the default edge, if necessary. */
7239 TREE_VEC_ELT (vec2, n2++) = gimple_switch_default_label (stmt);
7241 for (; i <= j; ++i, ++n2)
7242 TREE_VEC_ELT (vec2, n2) = gimple_switch_label (stmt, i);
7244 /* Mark needed edges. */
7245 for (i = 0; i < n2; ++i)
7247 e = find_edge (gimple_bb (stmt),
7248 label_to_block (CASE_LABEL (TREE_VEC_ELT (vec2, i))));
7249 e->aux = (void *)-1;
7252 /* Queue not needed edges for later removal. */
7253 FOR_EACH_EDGE (e, ei, gimple_bb (stmt)->succs)
7255 if (e->aux == (void *)-1)
7261 if (dump_file && (dump_flags & TDF_DETAILS))
7263 fprintf (dump_file, "removing unreachable case label\n");
7265 VEC_safe_push (edge, heap, to_remove_edges, e);
7266 e->flags &= ~EDGE_EXECUTABLE;
7269 /* And queue an update for the stmt. */
7272 VEC_safe_push (switch_update, heap, to_update_switch_stmts, &su);
7276 /* Simplify an integral conversion from an SSA name in STMT. */
7279 simplify_conversion_using_ranges (gimple stmt)
7281 tree innerop, middleop, finaltype;
7283 value_range_t *innervr;
7284 double_int innermin, innermax, middlemin, middlemax;
7286 finaltype = TREE_TYPE (gimple_assign_lhs (stmt));
7287 if (!INTEGRAL_TYPE_P (finaltype))
7289 middleop = gimple_assign_rhs1 (stmt);
7290 def_stmt = SSA_NAME_DEF_STMT (middleop);
7291 if (!is_gimple_assign (def_stmt)
7292 || !CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (def_stmt)))
7294 innerop = gimple_assign_rhs1 (def_stmt);
7295 if (TREE_CODE (innerop) != SSA_NAME)
7298 /* Get the value-range of the inner operand. */
7299 innervr = get_value_range (innerop);
7300 if (innervr->type != VR_RANGE
7301 || TREE_CODE (innervr->min) != INTEGER_CST
7302 || TREE_CODE (innervr->max) != INTEGER_CST)
7305 /* Simulate the conversion chain to check if the result is equal if
7306 the middle conversion is removed. */
7307 innermin = tree_to_double_int (innervr->min);
7308 innermax = tree_to_double_int (innervr->max);
7309 middlemin = double_int_ext (innermin, TYPE_PRECISION (TREE_TYPE (middleop)),
7310 TYPE_UNSIGNED (TREE_TYPE (middleop)));
7311 middlemax = double_int_ext (innermax, TYPE_PRECISION (TREE_TYPE (middleop)),
7312 TYPE_UNSIGNED (TREE_TYPE (middleop)));
7313 /* If the middle values do not represent a proper range fail. */
7314 if (double_int_cmp (middlemin, middlemax,
7315 TYPE_UNSIGNED (TREE_TYPE (middleop))) > 0)
7317 if (!double_int_equal_p (double_int_ext (middlemin,
7318 TYPE_PRECISION (finaltype),
7319 TYPE_UNSIGNED (finaltype)),
7320 double_int_ext (innermin,
7321 TYPE_PRECISION (finaltype),
7322 TYPE_UNSIGNED (finaltype)))
7323 || !double_int_equal_p (double_int_ext (middlemax,
7324 TYPE_PRECISION (finaltype),
7325 TYPE_UNSIGNED (finaltype)),
7326 double_int_ext (innermax,
7327 TYPE_PRECISION (finaltype),
7328 TYPE_UNSIGNED (finaltype))))
7331 gimple_assign_set_rhs1 (stmt, innerop);
7336 /* Return whether the value range *VR fits in an integer type specified
7337 by PRECISION and UNSIGNED_P. */
7340 range_fits_type_p (value_range_t *vr, unsigned precision, bool unsigned_p)
7343 unsigned src_precision;
7346 /* We can only handle integral and pointer types. */
7347 src_type = TREE_TYPE (vr->min);
7348 if (!INTEGRAL_TYPE_P (src_type)
7349 && !POINTER_TYPE_P (src_type))
7352 /* An extension is always fine, so is an identity transform. */
7353 src_precision = TYPE_PRECISION (TREE_TYPE (vr->min));
7354 if (src_precision < precision
7355 || (src_precision == precision
7356 && TYPE_UNSIGNED (src_type) == unsigned_p))
7359 /* Now we can only handle ranges with constant bounds. */
7360 if (vr->type != VR_RANGE
7361 || TREE_CODE (vr->min) != INTEGER_CST
7362 || TREE_CODE (vr->max) != INTEGER_CST)
7365 /* For precision-preserving sign-changes the MSB of the double-int
7367 if (src_precision == precision
7368 && (TREE_INT_CST_HIGH (vr->min) | TREE_INT_CST_HIGH (vr->max)) < 0)
7371 /* Then we can perform the conversion on both ends and compare
7372 the result for equality. */
7373 tem = double_int_ext (tree_to_double_int (vr->min), precision, unsigned_p);
7374 if (!double_int_equal_p (tree_to_double_int (vr->min), tem))
7376 tem = double_int_ext (tree_to_double_int (vr->max), precision, unsigned_p);
7377 if (!double_int_equal_p (tree_to_double_int (vr->max), tem))
7383 /* Simplify a conversion from integral SSA name to float in STMT. */
7386 simplify_float_conversion_using_ranges (gimple_stmt_iterator *gsi, gimple stmt)
7388 tree rhs1 = gimple_assign_rhs1 (stmt);
7389 value_range_t *vr = get_value_range (rhs1);
7390 enum machine_mode fltmode = TYPE_MODE (TREE_TYPE (gimple_assign_lhs (stmt)));
7391 enum machine_mode mode;
7395 /* We can only handle constant ranges. */
7396 if (vr->type != VR_RANGE
7397 || TREE_CODE (vr->min) != INTEGER_CST
7398 || TREE_CODE (vr->max) != INTEGER_CST)
7401 /* First check if we can use a signed type in place of an unsigned. */
7402 if (TYPE_UNSIGNED (TREE_TYPE (rhs1))
7403 && (can_float_p (fltmode, TYPE_MODE (TREE_TYPE (rhs1)), 0)
7404 != CODE_FOR_nothing)
7405 && range_fits_type_p (vr, GET_MODE_PRECISION
7406 (TYPE_MODE (TREE_TYPE (rhs1))), 0))
7407 mode = TYPE_MODE (TREE_TYPE (rhs1));
7408 /* If we can do the conversion in the current input mode do nothing. */
7409 else if (can_float_p (fltmode, TYPE_MODE (TREE_TYPE (rhs1)),
7410 TYPE_UNSIGNED (TREE_TYPE (rhs1))))
7412 /* Otherwise search for a mode we can use, starting from the narrowest
7413 integer mode available. */
7416 mode = GET_CLASS_NARROWEST_MODE (MODE_INT);
7419 /* If we cannot do a signed conversion to float from mode
7420 or if the value-range does not fit in the signed type
7421 try with a wider mode. */
7422 if (can_float_p (fltmode, mode, 0) != CODE_FOR_nothing
7423 && range_fits_type_p (vr, GET_MODE_PRECISION (mode), 0))
7426 mode = GET_MODE_WIDER_MODE (mode);
7427 /* But do not widen the input. Instead leave that to the
7428 optabs expansion code. */
7429 if (GET_MODE_PRECISION (mode) > TYPE_PRECISION (TREE_TYPE (rhs1)))
7432 while (mode != VOIDmode);
7433 if (mode == VOIDmode)
7437 /* It works, insert a truncation or sign-change before the
7438 float conversion. */
7439 tem = create_tmp_var (build_nonstandard_integer_type
7440 (GET_MODE_PRECISION (mode), 0), NULL);
7441 conv = gimple_build_assign_with_ops (NOP_EXPR, tem, rhs1, NULL_TREE);
7442 tem = make_ssa_name (tem, conv);
7443 gimple_assign_set_lhs (conv, tem);
7444 gsi_insert_before (gsi, conv, GSI_SAME_STMT);
7445 gimple_assign_set_rhs1 (stmt, tem);
7451 /* Simplify STMT using ranges if possible. */
7454 simplify_stmt_using_ranges (gimple_stmt_iterator *gsi)
7456 gimple stmt = gsi_stmt (*gsi);
7457 if (is_gimple_assign (stmt))
7459 enum tree_code rhs_code = gimple_assign_rhs_code (stmt);
7460 tree rhs1 = gimple_assign_rhs1 (stmt);
7466 /* Transform EQ_EXPR, NE_EXPR into BIT_XOR_EXPR or identity
7467 if the RHS is zero or one, and the LHS are known to be boolean
7469 if (INTEGRAL_TYPE_P (TREE_TYPE (rhs1)))
7470 return simplify_truth_ops_using_ranges (gsi, stmt);
7473 /* Transform TRUNC_DIV_EXPR and TRUNC_MOD_EXPR into RSHIFT_EXPR
7474 and BIT_AND_EXPR respectively if the first operand is greater
7475 than zero and the second operand is an exact power of two. */
7476 case TRUNC_DIV_EXPR:
7477 case TRUNC_MOD_EXPR:
7478 if (INTEGRAL_TYPE_P (TREE_TYPE (rhs1))
7479 && integer_pow2p (gimple_assign_rhs2 (stmt)))
7480 return simplify_div_or_mod_using_ranges (stmt);
7483 /* Transform ABS (X) into X or -X as appropriate. */
7485 if (TREE_CODE (rhs1) == SSA_NAME
7486 && INTEGRAL_TYPE_P (TREE_TYPE (rhs1)))
7487 return simplify_abs_using_ranges (stmt);
7492 /* Optimize away BIT_AND_EXPR and BIT_IOR_EXPR
7493 if all the bits being cleared are already cleared or
7494 all the bits being set are already set. */
7495 if (INTEGRAL_TYPE_P (TREE_TYPE (rhs1)))
7496 return simplify_bit_ops_using_ranges (gsi, stmt);
7500 if (TREE_CODE (rhs1) == SSA_NAME
7501 && INTEGRAL_TYPE_P (TREE_TYPE (rhs1)))
7502 return simplify_conversion_using_ranges (stmt);
7506 if (TREE_CODE (rhs1) == SSA_NAME
7507 && INTEGRAL_TYPE_P (TREE_TYPE (rhs1)))
7508 return simplify_float_conversion_using_ranges (gsi, stmt);
7515 else if (gimple_code (stmt) == GIMPLE_COND)
7516 return simplify_cond_using_ranges (stmt);
7517 else if (gimple_code (stmt) == GIMPLE_SWITCH)
7518 return simplify_switch_using_ranges (stmt);
7523 /* If the statement pointed by SI has a predicate whose value can be
7524 computed using the value range information computed by VRP, compute
7525 its value and return true. Otherwise, return false. */
7528 fold_predicate_in (gimple_stmt_iterator *si)
7530 bool assignment_p = false;
7532 gimple stmt = gsi_stmt (*si);
7534 if (is_gimple_assign (stmt)
7535 && TREE_CODE_CLASS (gimple_assign_rhs_code (stmt)) == tcc_comparison)
7537 assignment_p = true;
7538 val = vrp_evaluate_conditional (gimple_assign_rhs_code (stmt),
7539 gimple_assign_rhs1 (stmt),
7540 gimple_assign_rhs2 (stmt),
7543 else if (gimple_code (stmt) == GIMPLE_COND)
7544 val = vrp_evaluate_conditional (gimple_cond_code (stmt),
7545 gimple_cond_lhs (stmt),
7546 gimple_cond_rhs (stmt),
7554 val = fold_convert (gimple_expr_type (stmt), val);
7558 fprintf (dump_file, "Folding predicate ");
7559 print_gimple_expr (dump_file, stmt, 0, 0);
7560 fprintf (dump_file, " to ");
7561 print_generic_expr (dump_file, val, 0);
7562 fprintf (dump_file, "\n");
7565 if (is_gimple_assign (stmt))
7566 gimple_assign_set_rhs_from_tree (si, val);
7569 gcc_assert (gimple_code (stmt) == GIMPLE_COND);
7570 if (integer_zerop (val))
7571 gimple_cond_make_false (stmt);
7572 else if (integer_onep (val))
7573 gimple_cond_make_true (stmt);
7584 /* Callback for substitute_and_fold folding the stmt at *SI. */
7587 vrp_fold_stmt (gimple_stmt_iterator *si)
7589 if (fold_predicate_in (si))
7592 return simplify_stmt_using_ranges (si);
7595 /* Stack of dest,src equivalency pairs that need to be restored after
7596 each attempt to thread a block's incoming edge to an outgoing edge.
7598 A NULL entry is used to mark the end of pairs which need to be
7600 static VEC(tree,heap) *stack;
7602 /* A trivial wrapper so that we can present the generic jump threading
7603 code with a simple API for simplifying statements. STMT is the
7604 statement we want to simplify, WITHIN_STMT provides the location
7605 for any overflow warnings. */
7608 simplify_stmt_for_jump_threading (gimple stmt, gimple within_stmt)
7610 /* We only use VRP information to simplify conditionals. This is
7611 overly conservative, but it's unclear if doing more would be
7612 worth the compile time cost. */
7613 if (gimple_code (stmt) != GIMPLE_COND)
7616 return vrp_evaluate_conditional (gimple_cond_code (stmt),
7617 gimple_cond_lhs (stmt),
7618 gimple_cond_rhs (stmt), within_stmt);
7621 /* Blocks which have more than one predecessor and more than
7622 one successor present jump threading opportunities, i.e.,
7623 when the block is reached from a specific predecessor, we
7624 may be able to determine which of the outgoing edges will
7625 be traversed. When this optimization applies, we are able
7626 to avoid conditionals at runtime and we may expose secondary
7627 optimization opportunities.
7629 This routine is effectively a driver for the generic jump
7630 threading code. It basically just presents the generic code
7631 with edges that may be suitable for jump threading.
7633 Unlike DOM, we do not iterate VRP if jump threading was successful.
7634 While iterating may expose new opportunities for VRP, it is expected
7635 those opportunities would be very limited and the compile time cost
7636 to expose those opportunities would be significant.
7638 As jump threading opportunities are discovered, they are registered
7639 for later realization. */
7642 identify_jump_threads (void)
7649 /* Ugh. When substituting values earlier in this pass we can
7650 wipe the dominance information. So rebuild the dominator
7651 information as we need it within the jump threading code. */
7652 calculate_dominance_info (CDI_DOMINATORS);
7654 /* We do not allow VRP information to be used for jump threading
7655 across a back edge in the CFG. Otherwise it becomes too
7656 difficult to avoid eliminating loop exit tests. Of course
7657 EDGE_DFS_BACK is not accurate at this time so we have to
7659 mark_dfs_back_edges ();
7661 /* Do not thread across edges we are about to remove. Just marking
7662 them as EDGE_DFS_BACK will do. */
7663 FOR_EACH_VEC_ELT (edge, to_remove_edges, i, e)
7664 e->flags |= EDGE_DFS_BACK;
7666 /* Allocate our unwinder stack to unwind any temporary equivalences
7667 that might be recorded. */
7668 stack = VEC_alloc (tree, heap, 20);
7670 /* To avoid lots of silly node creation, we create a single
7671 conditional and just modify it in-place when attempting to
7673 dummy = gimple_build_cond (EQ_EXPR,
7674 integer_zero_node, integer_zero_node,
7677 /* Walk through all the blocks finding those which present a
7678 potential jump threading opportunity. We could set this up
7679 as a dominator walker and record data during the walk, but
7680 I doubt it's worth the effort for the classes of jump
7681 threading opportunities we are trying to identify at this
7682 point in compilation. */
7687 /* If the generic jump threading code does not find this block
7688 interesting, then there is nothing to do. */
7689 if (! potentially_threadable_block (bb))
7692 /* We only care about blocks ending in a COND_EXPR. While there
7693 may be some value in handling SWITCH_EXPR here, I doubt it's
7694 terribly important. */
7695 last = gsi_stmt (gsi_last_bb (bb));
7697 /* We're basically looking for a switch or any kind of conditional with
7698 integral or pointer type arguments. Note the type of the second
7699 argument will be the same as the first argument, so no need to
7700 check it explicitly. */
7701 if (gimple_code (last) == GIMPLE_SWITCH
7702 || (gimple_code (last) == GIMPLE_COND
7703 && TREE_CODE (gimple_cond_lhs (last)) == SSA_NAME
7704 && (INTEGRAL_TYPE_P (TREE_TYPE (gimple_cond_lhs (last)))
7705 || POINTER_TYPE_P (TREE_TYPE (gimple_cond_lhs (last))))
7706 && (TREE_CODE (gimple_cond_rhs (last)) == SSA_NAME
7707 || is_gimple_min_invariant (gimple_cond_rhs (last)))))
7711 /* We've got a block with multiple predecessors and multiple
7712 successors which also ends in a suitable conditional or
7713 switch statement. For each predecessor, see if we can thread
7714 it to a specific successor. */
7715 FOR_EACH_EDGE (e, ei, bb->preds)
7717 /* Do not thread across back edges or abnormal edges
7719 if (e->flags & (EDGE_DFS_BACK | EDGE_COMPLEX))
7722 thread_across_edge (dummy, e, true, &stack,
7723 simplify_stmt_for_jump_threading);
7728 /* We do not actually update the CFG or SSA graphs at this point as
7729 ASSERT_EXPRs are still in the IL and cfg cleanup code does not yet
7730 handle ASSERT_EXPRs gracefully. */
7733 /* We identified all the jump threading opportunities earlier, but could
7734 not transform the CFG at that time. This routine transforms the
7735 CFG and arranges for the dominator tree to be rebuilt if necessary.
7737 Note the SSA graph update will occur during the normal TODO
7738 processing by the pass manager. */
7740 finalize_jump_threads (void)
7742 thread_through_all_blocks (false);
7743 VEC_free (tree, heap, stack);
7747 /* Traverse all the blocks folding conditionals with known ranges. */
7754 values_propagated = true;
7758 fprintf (dump_file, "\nValue ranges after VRP:\n\n");
7759 dump_all_value_ranges (dump_file);
7760 fprintf (dump_file, "\n");
7763 substitute_and_fold (op_with_constant_singleton_value_range,
7764 vrp_fold_stmt, false);
7766 if (warn_array_bounds)
7767 check_all_array_refs ();
7769 /* We must identify jump threading opportunities before we release
7770 the datastructures built by VRP. */
7771 identify_jump_threads ();
7773 /* Free allocated memory. */
7774 for (i = 0; i < num_vr_values; i++)
7777 BITMAP_FREE (vr_value[i]->equiv);
7782 free (vr_phi_edge_counts);
7784 /* So that we can distinguish between VRP data being available
7785 and not available. */
7787 vr_phi_edge_counts = NULL;
7791 /* Main entry point to VRP (Value Range Propagation). This pass is
7792 loosely based on J. R. C. Patterson, ``Accurate Static Branch
7793 Prediction by Value Range Propagation,'' in SIGPLAN Conference on
7794 Programming Language Design and Implementation, pp. 67-78, 1995.
7795 Also available at http://citeseer.ist.psu.edu/patterson95accurate.html
7797 This is essentially an SSA-CCP pass modified to deal with ranges
7798 instead of constants.
7800 While propagating ranges, we may find that two or more SSA name
7801 have equivalent, though distinct ranges. For instance,
7804 2 p_4 = ASSERT_EXPR <p_3, p_3 != 0>
7806 4 p_5 = ASSERT_EXPR <p_4, p_4 == q_2>;
7810 In the code above, pointer p_5 has range [q_2, q_2], but from the
7811 code we can also determine that p_5 cannot be NULL and, if q_2 had
7812 a non-varying range, p_5's range should also be compatible with it.
7814 These equivalences are created by two expressions: ASSERT_EXPR and
7815 copy operations. Since p_5 is an assertion on p_4, and p_4 was the
7816 result of another assertion, then we can use the fact that p_5 and
7817 p_4 are equivalent when evaluating p_5's range.
7819 Together with value ranges, we also propagate these equivalences
7820 between names so that we can take advantage of information from
7821 multiple ranges when doing final replacement. Note that this
7822 equivalency relation is transitive but not symmetric.
7824 In the example above, p_5 is equivalent to p_4, q_2 and p_3, but we
7825 cannot assert that q_2 is equivalent to p_5 because q_2 may be used
7826 in contexts where that assertion does not hold (e.g., in line 6).
7828 TODO, the main difference between this pass and Patterson's is that
7829 we do not propagate edge probabilities. We only compute whether
7830 edges can be taken or not. That is, instead of having a spectrum
7831 of jump probabilities between 0 and 1, we only deal with 0, 1 and
7832 DON'T KNOW. In the future, it may be worthwhile to propagate
7833 probabilities to aid branch prediction. */
7842 loop_optimizer_init (LOOPS_NORMAL | LOOPS_HAVE_RECORDED_EXITS);
7843 rewrite_into_loop_closed_ssa (NULL, TODO_update_ssa);
7846 insert_range_assertions ();
7848 /* Estimate number of iterations - but do not use undefined behavior
7849 for this. We can't do this lazily as other functions may compute
7850 this using undefined behavior. */
7851 free_numbers_of_iterations_estimates ();
7852 estimate_numbers_of_iterations (false);
7854 to_remove_edges = VEC_alloc (edge, heap, 10);
7855 to_update_switch_stmts = VEC_alloc (switch_update, heap, 5);
7856 threadedge_initialize_values ();
7859 ssa_propagate (vrp_visit_stmt, vrp_visit_phi_node);
7862 free_numbers_of_iterations_estimates ();
7864 /* ASSERT_EXPRs must be removed before finalizing jump threads
7865 as finalizing jump threads calls the CFG cleanup code which
7866 does not properly handle ASSERT_EXPRs. */
7867 remove_range_assertions ();
7869 /* If we exposed any new variables, go ahead and put them into
7870 SSA form now, before we handle jump threading. This simplifies
7871 interactions between rewriting of _DECL nodes into SSA form
7872 and rewriting SSA_NAME nodes into SSA form after block
7873 duplication and CFG manipulation. */
7874 update_ssa (TODO_update_ssa);
7876 finalize_jump_threads ();
7878 /* Remove dead edges from SWITCH_EXPR optimization. This leaves the
7879 CFG in a broken state and requires a cfg_cleanup run. */
7880 FOR_EACH_VEC_ELT (edge, to_remove_edges, i, e)
7882 /* Update SWITCH_EXPR case label vector. */
7883 FOR_EACH_VEC_ELT (switch_update, to_update_switch_stmts, i, su)
7886 size_t n = TREE_VEC_LENGTH (su->vec);
7888 gimple_switch_set_num_labels (su->stmt, n);
7889 for (j = 0; j < n; j++)
7890 gimple_switch_set_label (su->stmt, j, TREE_VEC_ELT (su->vec, j));
7891 /* As we may have replaced the default label with a regular one
7892 make sure to make it a real default label again. This ensures
7893 optimal expansion. */
7894 label = gimple_switch_default_label (su->stmt);
7895 CASE_LOW (label) = NULL_TREE;
7896 CASE_HIGH (label) = NULL_TREE;
7899 if (VEC_length (edge, to_remove_edges) > 0)
7900 free_dominance_info (CDI_DOMINATORS);
7902 VEC_free (edge, heap, to_remove_edges);
7903 VEC_free (switch_update, heap, to_update_switch_stmts);
7904 threadedge_finalize_values ();
7907 loop_optimizer_finalize ();
7914 return flag_tree_vrp != 0;
7917 struct gimple_opt_pass pass_vrp =
7922 gate_vrp, /* gate */
7923 execute_vrp, /* execute */
7926 0, /* static_pass_number */
7927 TV_TREE_VRP, /* tv_id */
7928 PROP_ssa, /* properties_required */
7929 0, /* properties_provided */
7930 0, /* properties_destroyed */
7931 0, /* todo_flags_start */
7936 | TODO_ggc_collect /* todo_flags_finish */