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, the variable can take any value
697 sym = SSA_NAME_VAR (var);
698 if (SSA_NAME_IS_DEFAULT_DEF (var))
700 /* Try to use the "nonnull" attribute to create ~[0, 0]
701 anti-ranges for pointers. Note that this is only valid with
702 default definitions of PARM_DECLs. */
703 if (TREE_CODE (sym) == PARM_DECL
704 && 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 /* Like tree_expr_nonnegative_warnv_p, but this function uses value
879 ranges obtained so far. */
882 vrp_expr_computes_nonnegative (tree expr, bool *strict_overflow_p)
884 return (tree_expr_nonnegative_warnv_p (expr, strict_overflow_p)
885 || (TREE_CODE (expr) == SSA_NAME
886 && ssa_name_nonnegative_p (expr)));
889 /* Return true if the result of assignment STMT is know to be non-negative.
890 If the return value is based on the assumption that signed overflow is
891 undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't change
892 *STRICT_OVERFLOW_P.*/
895 gimple_assign_nonnegative_warnv_p (gimple stmt, bool *strict_overflow_p)
897 enum tree_code code = gimple_assign_rhs_code (stmt);
898 switch (get_gimple_rhs_class (code))
900 case GIMPLE_UNARY_RHS:
901 return tree_unary_nonnegative_warnv_p (gimple_assign_rhs_code (stmt),
902 gimple_expr_type (stmt),
903 gimple_assign_rhs1 (stmt),
905 case GIMPLE_BINARY_RHS:
906 return tree_binary_nonnegative_warnv_p (gimple_assign_rhs_code (stmt),
907 gimple_expr_type (stmt),
908 gimple_assign_rhs1 (stmt),
909 gimple_assign_rhs2 (stmt),
911 case GIMPLE_TERNARY_RHS:
913 case GIMPLE_SINGLE_RHS:
914 return tree_single_nonnegative_warnv_p (gimple_assign_rhs1 (stmt),
916 case GIMPLE_INVALID_RHS:
923 /* Return true if return value of call STMT is know to be non-negative.
924 If the return value is based on the assumption that signed overflow is
925 undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't change
926 *STRICT_OVERFLOW_P.*/
929 gimple_call_nonnegative_warnv_p (gimple stmt, bool *strict_overflow_p)
931 tree arg0 = gimple_call_num_args (stmt) > 0 ?
932 gimple_call_arg (stmt, 0) : NULL_TREE;
933 tree arg1 = gimple_call_num_args (stmt) > 1 ?
934 gimple_call_arg (stmt, 1) : NULL_TREE;
936 return tree_call_nonnegative_warnv_p (gimple_expr_type (stmt),
937 gimple_call_fndecl (stmt),
943 /* Return true if STMT is know to to compute a non-negative value.
944 If the return value is based on the assumption that signed overflow is
945 undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't change
946 *STRICT_OVERFLOW_P.*/
949 gimple_stmt_nonnegative_warnv_p (gimple stmt, bool *strict_overflow_p)
951 switch (gimple_code (stmt))
954 return gimple_assign_nonnegative_warnv_p (stmt, strict_overflow_p);
956 return gimple_call_nonnegative_warnv_p (stmt, strict_overflow_p);
962 /* Return true if the result of assignment STMT is know to be non-zero.
963 If the return value is based on the assumption that signed overflow is
964 undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't change
965 *STRICT_OVERFLOW_P.*/
968 gimple_assign_nonzero_warnv_p (gimple stmt, bool *strict_overflow_p)
970 enum tree_code code = gimple_assign_rhs_code (stmt);
971 switch (get_gimple_rhs_class (code))
973 case GIMPLE_UNARY_RHS:
974 return tree_unary_nonzero_warnv_p (gimple_assign_rhs_code (stmt),
975 gimple_expr_type (stmt),
976 gimple_assign_rhs1 (stmt),
978 case GIMPLE_BINARY_RHS:
979 return tree_binary_nonzero_warnv_p (gimple_assign_rhs_code (stmt),
980 gimple_expr_type (stmt),
981 gimple_assign_rhs1 (stmt),
982 gimple_assign_rhs2 (stmt),
984 case GIMPLE_TERNARY_RHS:
986 case GIMPLE_SINGLE_RHS:
987 return tree_single_nonzero_warnv_p (gimple_assign_rhs1 (stmt),
989 case GIMPLE_INVALID_RHS:
996 /* Return true if STMT is know to to compute a non-zero value.
997 If the return value is based on the assumption that signed overflow is
998 undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't change
999 *STRICT_OVERFLOW_P.*/
1002 gimple_stmt_nonzero_warnv_p (gimple stmt, bool *strict_overflow_p)
1004 switch (gimple_code (stmt))
1007 return gimple_assign_nonzero_warnv_p (stmt, strict_overflow_p);
1009 return gimple_alloca_call_p (stmt);
1015 /* Like tree_expr_nonzero_warnv_p, but this function uses value ranges
1019 vrp_stmt_computes_nonzero (gimple stmt, bool *strict_overflow_p)
1021 if (gimple_stmt_nonzero_warnv_p (stmt, strict_overflow_p))
1024 /* If we have an expression of the form &X->a, then the expression
1025 is nonnull if X is nonnull. */
1026 if (is_gimple_assign (stmt)
1027 && gimple_assign_rhs_code (stmt) == ADDR_EXPR)
1029 tree expr = gimple_assign_rhs1 (stmt);
1030 tree base = get_base_address (TREE_OPERAND (expr, 0));
1032 if (base != NULL_TREE
1033 && TREE_CODE (base) == MEM_REF
1034 && TREE_CODE (TREE_OPERAND (base, 0)) == SSA_NAME)
1036 value_range_t *vr = get_value_range (TREE_OPERAND (base, 0));
1037 if (range_is_nonnull (vr))
1045 /* Returns true if EXPR is a valid value (as expected by compare_values) --
1046 a gimple invariant, or SSA_NAME +- CST. */
1049 valid_value_p (tree expr)
1051 if (TREE_CODE (expr) == SSA_NAME)
1054 if (TREE_CODE (expr) == PLUS_EXPR
1055 || TREE_CODE (expr) == MINUS_EXPR)
1056 return (TREE_CODE (TREE_OPERAND (expr, 0)) == SSA_NAME
1057 && TREE_CODE (TREE_OPERAND (expr, 1)) == INTEGER_CST);
1059 return is_gimple_min_invariant (expr);
1065 -2 if those are incomparable. */
1067 operand_less_p (tree val, tree val2)
1069 /* LT is folded faster than GE and others. Inline the common case. */
1070 if (TREE_CODE (val) == INTEGER_CST && TREE_CODE (val2) == INTEGER_CST)
1072 if (TYPE_UNSIGNED (TREE_TYPE (val)))
1073 return INT_CST_LT_UNSIGNED (val, val2);
1076 if (INT_CST_LT (val, val2))
1084 fold_defer_overflow_warnings ();
1086 tcmp = fold_binary_to_constant (LT_EXPR, boolean_type_node, val, val2);
1088 fold_undefer_and_ignore_overflow_warnings ();
1091 || TREE_CODE (tcmp) != INTEGER_CST)
1094 if (!integer_zerop (tcmp))
1098 /* val >= val2, not considering overflow infinity. */
1099 if (is_negative_overflow_infinity (val))
1100 return is_negative_overflow_infinity (val2) ? 0 : 1;
1101 else if (is_positive_overflow_infinity (val2))
1102 return is_positive_overflow_infinity (val) ? 0 : 1;
1107 /* Compare two values VAL1 and VAL2. Return
1109 -2 if VAL1 and VAL2 cannot be compared at compile-time,
1112 +1 if VAL1 > VAL2, and
1115 This is similar to tree_int_cst_compare but supports pointer values
1116 and values that cannot be compared at compile time.
1118 If STRICT_OVERFLOW_P is not NULL, then set *STRICT_OVERFLOW_P to
1119 true if the return value is only valid if we assume that signed
1120 overflow is undefined. */
1123 compare_values_warnv (tree val1, tree val2, bool *strict_overflow_p)
1128 /* Below we rely on the fact that VAL1 and VAL2 are both pointers or
1130 gcc_assert (POINTER_TYPE_P (TREE_TYPE (val1))
1131 == POINTER_TYPE_P (TREE_TYPE (val2)));
1132 /* Convert the two values into the same type. This is needed because
1133 sizetype causes sign extension even for unsigned types. */
1134 val2 = fold_convert (TREE_TYPE (val1), val2);
1135 STRIP_USELESS_TYPE_CONVERSION (val2);
1137 if ((TREE_CODE (val1) == SSA_NAME
1138 || TREE_CODE (val1) == PLUS_EXPR
1139 || TREE_CODE (val1) == MINUS_EXPR)
1140 && (TREE_CODE (val2) == SSA_NAME
1141 || TREE_CODE (val2) == PLUS_EXPR
1142 || TREE_CODE (val2) == MINUS_EXPR))
1144 tree n1, c1, n2, c2;
1145 enum tree_code code1, code2;
1147 /* If VAL1 and VAL2 are of the form 'NAME [+-] CST' or 'NAME',
1148 return -1 or +1 accordingly. If VAL1 and VAL2 don't use the
1149 same name, return -2. */
1150 if (TREE_CODE (val1) == SSA_NAME)
1158 code1 = TREE_CODE (val1);
1159 n1 = TREE_OPERAND (val1, 0);
1160 c1 = TREE_OPERAND (val1, 1);
1161 if (tree_int_cst_sgn (c1) == -1)
1163 if (is_negative_overflow_infinity (c1))
1165 c1 = fold_unary_to_constant (NEGATE_EXPR, TREE_TYPE (c1), c1);
1168 code1 = code1 == MINUS_EXPR ? PLUS_EXPR : MINUS_EXPR;
1172 if (TREE_CODE (val2) == SSA_NAME)
1180 code2 = TREE_CODE (val2);
1181 n2 = TREE_OPERAND (val2, 0);
1182 c2 = TREE_OPERAND (val2, 1);
1183 if (tree_int_cst_sgn (c2) == -1)
1185 if (is_negative_overflow_infinity (c2))
1187 c2 = fold_unary_to_constant (NEGATE_EXPR, TREE_TYPE (c2), c2);
1190 code2 = code2 == MINUS_EXPR ? PLUS_EXPR : MINUS_EXPR;
1194 /* Both values must use the same name. */
1198 if (code1 == SSA_NAME
1199 && code2 == SSA_NAME)
1203 /* If overflow is defined we cannot simplify more. */
1204 if (!TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (val1)))
1207 if (strict_overflow_p != NULL
1208 && (code1 == SSA_NAME || !TREE_NO_WARNING (val1))
1209 && (code2 == SSA_NAME || !TREE_NO_WARNING (val2)))
1210 *strict_overflow_p = true;
1212 if (code1 == SSA_NAME)
1214 if (code2 == PLUS_EXPR)
1215 /* NAME < NAME + CST */
1217 else if (code2 == MINUS_EXPR)
1218 /* NAME > NAME - CST */
1221 else if (code1 == PLUS_EXPR)
1223 if (code2 == SSA_NAME)
1224 /* NAME + CST > NAME */
1226 else if (code2 == PLUS_EXPR)
1227 /* NAME + CST1 > NAME + CST2, if CST1 > CST2 */
1228 return compare_values_warnv (c1, c2, strict_overflow_p);
1229 else if (code2 == MINUS_EXPR)
1230 /* NAME + CST1 > NAME - CST2 */
1233 else if (code1 == MINUS_EXPR)
1235 if (code2 == SSA_NAME)
1236 /* NAME - CST < NAME */
1238 else if (code2 == PLUS_EXPR)
1239 /* NAME - CST1 < NAME + CST2 */
1241 else if (code2 == MINUS_EXPR)
1242 /* NAME - CST1 > NAME - CST2, if CST1 < CST2. Notice that
1243 C1 and C2 are swapped in the call to compare_values. */
1244 return compare_values_warnv (c2, c1, strict_overflow_p);
1250 /* We cannot compare non-constants. */
1251 if (!is_gimple_min_invariant (val1) || !is_gimple_min_invariant (val2))
1254 if (!POINTER_TYPE_P (TREE_TYPE (val1)))
1256 /* We cannot compare overflowed values, except for overflow
1258 if (TREE_OVERFLOW (val1) || TREE_OVERFLOW (val2))
1260 if (strict_overflow_p != NULL)
1261 *strict_overflow_p = true;
1262 if (is_negative_overflow_infinity (val1))
1263 return is_negative_overflow_infinity (val2) ? 0 : -1;
1264 else if (is_negative_overflow_infinity (val2))
1266 else if (is_positive_overflow_infinity (val1))
1267 return is_positive_overflow_infinity (val2) ? 0 : 1;
1268 else if (is_positive_overflow_infinity (val2))
1273 return tree_int_cst_compare (val1, val2);
1279 /* First see if VAL1 and VAL2 are not the same. */
1280 if (val1 == val2 || operand_equal_p (val1, val2, 0))
1283 /* If VAL1 is a lower address than VAL2, return -1. */
1284 if (operand_less_p (val1, val2) == 1)
1287 /* If VAL1 is a higher address than VAL2, return +1. */
1288 if (operand_less_p (val2, val1) == 1)
1291 /* If VAL1 is different than VAL2, return +2.
1292 For integer constants we either have already returned -1 or 1
1293 or they are equivalent. We still might succeed in proving
1294 something about non-trivial operands. */
1295 if (TREE_CODE (val1) != INTEGER_CST
1296 || TREE_CODE (val2) != INTEGER_CST)
1298 t = fold_binary_to_constant (NE_EXPR, boolean_type_node, val1, val2);
1299 if (t && integer_onep (t))
1307 /* Compare values like compare_values_warnv, but treat comparisons of
1308 nonconstants which rely on undefined overflow as incomparable. */
1311 compare_values (tree val1, tree val2)
1317 ret = compare_values_warnv (val1, val2, &sop);
1319 && (!is_gimple_min_invariant (val1) || !is_gimple_min_invariant (val2)))
1325 /* Return 1 if VAL is inside value range VR (VR->MIN <= VAL <= VR->MAX),
1326 0 if VAL is not inside VR,
1327 -2 if we cannot tell either way.
1329 FIXME, the current semantics of this functions are a bit quirky
1330 when taken in the context of VRP. In here we do not care
1331 about VR's type. If VR is the anti-range ~[3, 5] the call
1332 value_inside_range (4, VR) will return 1.
1334 This is counter-intuitive in a strict sense, but the callers
1335 currently expect this. They are calling the function
1336 merely to determine whether VR->MIN <= VAL <= VR->MAX. The
1337 callers are applying the VR_RANGE/VR_ANTI_RANGE semantics
1340 This also applies to value_ranges_intersect_p and
1341 range_includes_zero_p. The semantics of VR_RANGE and
1342 VR_ANTI_RANGE should be encoded here, but that also means
1343 adapting the users of these functions to the new semantics.
1345 Benchmark compile/20001226-1.c compilation time after changing this
1349 value_inside_range (tree val, value_range_t * vr)
1353 cmp1 = operand_less_p (val, vr->min);
1359 cmp2 = operand_less_p (vr->max, val);
1367 /* Return true if value ranges VR0 and VR1 have a non-empty
1370 Benchmark compile/20001226-1.c compilation time after changing this
1375 value_ranges_intersect_p (value_range_t *vr0, value_range_t *vr1)
1377 /* The value ranges do not intersect if the maximum of the first range is
1378 less than the minimum of the second range or vice versa.
1379 When those relations are unknown, we can't do any better. */
1380 if (operand_less_p (vr0->max, vr1->min) != 0)
1382 if (operand_less_p (vr1->max, vr0->min) != 0)
1388 /* Return true if VR includes the value zero, false otherwise. FIXME,
1389 currently this will return false for an anti-range like ~[-4, 3].
1390 This will be wrong when the semantics of value_inside_range are
1391 modified (currently the users of this function expect these
1395 range_includes_zero_p (value_range_t *vr)
1399 gcc_assert (vr->type != VR_UNDEFINED
1400 && vr->type != VR_VARYING
1401 && !symbolic_range_p (vr));
1403 zero = build_int_cst (TREE_TYPE (vr->min), 0);
1404 return (value_inside_range (zero, vr) == 1);
1407 /* Return true if T, an SSA_NAME, is known to be nonnegative. Return
1408 false otherwise or if no value range information is available. */
1411 ssa_name_nonnegative_p (const_tree t)
1413 value_range_t *vr = get_value_range (t);
1415 if (INTEGRAL_TYPE_P (t)
1416 && TYPE_UNSIGNED (t))
1422 /* Testing for VR_ANTI_RANGE is not useful here as any anti-range
1423 which would return a useful value should be encoded as a VR_RANGE. */
1424 if (vr->type == VR_RANGE)
1426 int result = compare_values (vr->min, integer_zero_node);
1428 return (result == 0 || result == 1);
1433 /* If OP has a value range with a single constant value return that,
1434 otherwise return NULL_TREE. This returns OP itself if OP is a
1438 op_with_constant_singleton_value_range (tree op)
1442 if (is_gimple_min_invariant (op))
1445 if (TREE_CODE (op) != SSA_NAME)
1448 vr = get_value_range (op);
1449 if (vr->type == VR_RANGE
1450 && operand_equal_p (vr->min, vr->max, 0)
1451 && is_gimple_min_invariant (vr->min))
1458 /* Extract value range information from an ASSERT_EXPR EXPR and store
1462 extract_range_from_assert (value_range_t *vr_p, tree expr)
1464 tree var, cond, limit, min, max, type;
1465 value_range_t *var_vr, *limit_vr;
1466 enum tree_code cond_code;
1468 var = ASSERT_EXPR_VAR (expr);
1469 cond = ASSERT_EXPR_COND (expr);
1471 gcc_assert (COMPARISON_CLASS_P (cond));
1473 /* Find VAR in the ASSERT_EXPR conditional. */
1474 if (var == TREE_OPERAND (cond, 0)
1475 || TREE_CODE (TREE_OPERAND (cond, 0)) == PLUS_EXPR
1476 || TREE_CODE (TREE_OPERAND (cond, 0)) == NOP_EXPR)
1478 /* If the predicate is of the form VAR COMP LIMIT, then we just
1479 take LIMIT from the RHS and use the same comparison code. */
1480 cond_code = TREE_CODE (cond);
1481 limit = TREE_OPERAND (cond, 1);
1482 cond = TREE_OPERAND (cond, 0);
1486 /* If the predicate is of the form LIMIT COMP VAR, then we need
1487 to flip around the comparison code to create the proper range
1489 cond_code = swap_tree_comparison (TREE_CODE (cond));
1490 limit = TREE_OPERAND (cond, 0);
1491 cond = TREE_OPERAND (cond, 1);
1494 limit = avoid_overflow_infinity (limit);
1496 type = TREE_TYPE (limit);
1497 gcc_assert (limit != var);
1499 /* For pointer arithmetic, we only keep track of pointer equality
1501 if (POINTER_TYPE_P (type) && cond_code != NE_EXPR && cond_code != EQ_EXPR)
1503 set_value_range_to_varying (vr_p);
1507 /* If LIMIT is another SSA name and LIMIT has a range of its own,
1508 try to use LIMIT's range to avoid creating symbolic ranges
1510 limit_vr = (TREE_CODE (limit) == SSA_NAME) ? get_value_range (limit) : NULL;
1512 /* LIMIT's range is only interesting if it has any useful information. */
1514 && (limit_vr->type == VR_UNDEFINED
1515 || limit_vr->type == VR_VARYING
1516 || symbolic_range_p (limit_vr)))
1519 /* Initially, the new range has the same set of equivalences of
1520 VAR's range. This will be revised before returning the final
1521 value. Since assertions may be chained via mutually exclusive
1522 predicates, we will need to trim the set of equivalences before
1524 gcc_assert (vr_p->equiv == NULL);
1525 add_equivalence (&vr_p->equiv, var);
1527 /* Extract a new range based on the asserted comparison for VAR and
1528 LIMIT's value range. Notice that if LIMIT has an anti-range, we
1529 will only use it for equality comparisons (EQ_EXPR). For any
1530 other kind of assertion, we cannot derive a range from LIMIT's
1531 anti-range that can be used to describe the new range. For
1532 instance, ASSERT_EXPR <x_2, x_2 <= b_4>. If b_4 is ~[2, 10],
1533 then b_4 takes on the ranges [-INF, 1] and [11, +INF]. There is
1534 no single range for x_2 that could describe LE_EXPR, so we might
1535 as well build the range [b_4, +INF] for it.
1536 One special case we handle is extracting a range from a
1537 range test encoded as (unsigned)var + CST <= limit. */
1538 if (TREE_CODE (cond) == NOP_EXPR
1539 || TREE_CODE (cond) == PLUS_EXPR)
1541 if (TREE_CODE (cond) == PLUS_EXPR)
1543 min = fold_build1 (NEGATE_EXPR, TREE_TYPE (TREE_OPERAND (cond, 1)),
1544 TREE_OPERAND (cond, 1));
1545 max = int_const_binop (PLUS_EXPR, limit, min);
1546 cond = TREE_OPERAND (cond, 0);
1550 min = build_int_cst (TREE_TYPE (var), 0);
1554 /* Make sure to not set TREE_OVERFLOW on the final type
1555 conversion. We are willingly interpreting large positive
1556 unsigned values as negative singed values here. */
1557 min = force_fit_type_double (TREE_TYPE (var), tree_to_double_int (min),
1559 max = force_fit_type_double (TREE_TYPE (var), tree_to_double_int (max),
1562 /* We can transform a max, min range to an anti-range or
1563 vice-versa. Use set_and_canonicalize_value_range which does
1565 if (cond_code == LE_EXPR)
1566 set_and_canonicalize_value_range (vr_p, VR_RANGE,
1567 min, max, vr_p->equiv);
1568 else if (cond_code == GT_EXPR)
1569 set_and_canonicalize_value_range (vr_p, VR_ANTI_RANGE,
1570 min, max, vr_p->equiv);
1574 else if (cond_code == EQ_EXPR)
1576 enum value_range_type range_type;
1580 range_type = limit_vr->type;
1581 min = limit_vr->min;
1582 max = limit_vr->max;
1586 range_type = VR_RANGE;
1591 set_value_range (vr_p, range_type, min, max, vr_p->equiv);
1593 /* When asserting the equality VAR == LIMIT and LIMIT is another
1594 SSA name, the new range will also inherit the equivalence set
1596 if (TREE_CODE (limit) == SSA_NAME)
1597 add_equivalence (&vr_p->equiv, limit);
1599 else if (cond_code == NE_EXPR)
1601 /* As described above, when LIMIT's range is an anti-range and
1602 this assertion is an inequality (NE_EXPR), then we cannot
1603 derive anything from the anti-range. For instance, if
1604 LIMIT's range was ~[0, 0], the assertion 'VAR != LIMIT' does
1605 not imply that VAR's range is [0, 0]. So, in the case of
1606 anti-ranges, we just assert the inequality using LIMIT and
1609 If LIMIT_VR is a range, we can only use it to build a new
1610 anti-range if LIMIT_VR is a single-valued range. For
1611 instance, if LIMIT_VR is [0, 1], the predicate
1612 VAR != [0, 1] does not mean that VAR's range is ~[0, 1].
1613 Rather, it means that for value 0 VAR should be ~[0, 0]
1614 and for value 1, VAR should be ~[1, 1]. We cannot
1615 represent these ranges.
1617 The only situation in which we can build a valid
1618 anti-range is when LIMIT_VR is a single-valued range
1619 (i.e., LIMIT_VR->MIN == LIMIT_VR->MAX). In that case,
1620 build the anti-range ~[LIMIT_VR->MIN, LIMIT_VR->MAX]. */
1622 && limit_vr->type == VR_RANGE
1623 && compare_values (limit_vr->min, limit_vr->max) == 0)
1625 min = limit_vr->min;
1626 max = limit_vr->max;
1630 /* In any other case, we cannot use LIMIT's range to build a
1631 valid anti-range. */
1635 /* If MIN and MAX cover the whole range for their type, then
1636 just use the original LIMIT. */
1637 if (INTEGRAL_TYPE_P (type)
1638 && vrp_val_is_min (min)
1639 && vrp_val_is_max (max))
1642 set_value_range (vr_p, VR_ANTI_RANGE, min, max, vr_p->equiv);
1644 else if (cond_code == LE_EXPR || cond_code == LT_EXPR)
1646 min = TYPE_MIN_VALUE (type);
1648 if (limit_vr == NULL || limit_vr->type == VR_ANTI_RANGE)
1652 /* If LIMIT_VR is of the form [N1, N2], we need to build the
1653 range [MIN, N2] for LE_EXPR and [MIN, N2 - 1] for
1655 max = limit_vr->max;
1658 /* If the maximum value forces us to be out of bounds, simply punt.
1659 It would be pointless to try and do anything more since this
1660 all should be optimized away above us. */
1661 if ((cond_code == LT_EXPR
1662 && compare_values (max, min) == 0)
1663 || (CONSTANT_CLASS_P (max) && TREE_OVERFLOW (max)))
1664 set_value_range_to_varying (vr_p);
1667 /* For LT_EXPR, we create the range [MIN, MAX - 1]. */
1668 if (cond_code == LT_EXPR)
1670 tree one = build_int_cst (type, 1);
1671 max = fold_build2 (MINUS_EXPR, type, max, one);
1673 TREE_NO_WARNING (max) = 1;
1676 set_value_range (vr_p, VR_RANGE, min, max, vr_p->equiv);
1679 else if (cond_code == GE_EXPR || cond_code == GT_EXPR)
1681 max = TYPE_MAX_VALUE (type);
1683 if (limit_vr == NULL || limit_vr->type == VR_ANTI_RANGE)
1687 /* If LIMIT_VR is of the form [N1, N2], we need to build the
1688 range [N1, MAX] for GE_EXPR and [N1 + 1, MAX] for
1690 min = limit_vr->min;
1693 /* If the minimum value forces us to be out of bounds, simply punt.
1694 It would be pointless to try and do anything more since this
1695 all should be optimized away above us. */
1696 if ((cond_code == GT_EXPR
1697 && compare_values (min, max) == 0)
1698 || (CONSTANT_CLASS_P (min) && TREE_OVERFLOW (min)))
1699 set_value_range_to_varying (vr_p);
1702 /* For GT_EXPR, we create the range [MIN + 1, MAX]. */
1703 if (cond_code == GT_EXPR)
1705 tree one = build_int_cst (type, 1);
1706 min = fold_build2 (PLUS_EXPR, type, min, one);
1708 TREE_NO_WARNING (min) = 1;
1711 set_value_range (vr_p, VR_RANGE, min, max, vr_p->equiv);
1717 /* If VAR already had a known range, it may happen that the new
1718 range we have computed and VAR's range are not compatible. For
1722 p_6 = ASSERT_EXPR <p_5, p_5 == NULL>;
1724 p_8 = ASSERT_EXPR <p_6, p_6 != NULL>;
1726 While the above comes from a faulty program, it will cause an ICE
1727 later because p_8 and p_6 will have incompatible ranges and at
1728 the same time will be considered equivalent. A similar situation
1732 i_6 = ASSERT_EXPR <i_5, i_5 > 10>;
1734 i_7 = ASSERT_EXPR <i_6, i_6 < 5>;
1736 Again i_6 and i_7 will have incompatible ranges. It would be
1737 pointless to try and do anything with i_7's range because
1738 anything dominated by 'if (i_5 < 5)' will be optimized away.
1739 Note, due to the wa in which simulation proceeds, the statement
1740 i_7 = ASSERT_EXPR <...> we would never be visited because the
1741 conditional 'if (i_5 < 5)' always evaluates to false. However,
1742 this extra check does not hurt and may protect against future
1743 changes to VRP that may get into a situation similar to the
1744 NULL pointer dereference example.
1746 Note that these compatibility tests are only needed when dealing
1747 with ranges or a mix of range and anti-range. If VAR_VR and VR_P
1748 are both anti-ranges, they will always be compatible, because two
1749 anti-ranges will always have a non-empty intersection. */
1751 var_vr = get_value_range (var);
1753 /* We may need to make adjustments when VR_P and VAR_VR are numeric
1754 ranges or anti-ranges. */
1755 if (vr_p->type == VR_VARYING
1756 || vr_p->type == VR_UNDEFINED
1757 || var_vr->type == VR_VARYING
1758 || var_vr->type == VR_UNDEFINED
1759 || symbolic_range_p (vr_p)
1760 || symbolic_range_p (var_vr))
1763 if (var_vr->type == VR_RANGE && vr_p->type == VR_RANGE)
1765 /* If the two ranges have a non-empty intersection, we can
1766 refine the resulting range. Since the assert expression
1767 creates an equivalency and at the same time it asserts a
1768 predicate, we can take the intersection of the two ranges to
1769 get better precision. */
1770 if (value_ranges_intersect_p (var_vr, vr_p))
1772 /* Use the larger of the two minimums. */
1773 if (compare_values (vr_p->min, var_vr->min) == -1)
1778 /* Use the smaller of the two maximums. */
1779 if (compare_values (vr_p->max, var_vr->max) == 1)
1784 set_value_range (vr_p, vr_p->type, min, max, vr_p->equiv);
1788 /* The two ranges do not intersect, set the new range to
1789 VARYING, because we will not be able to do anything
1790 meaningful with it. */
1791 set_value_range_to_varying (vr_p);
1794 else if ((var_vr->type == VR_RANGE && vr_p->type == VR_ANTI_RANGE)
1795 || (var_vr->type == VR_ANTI_RANGE && vr_p->type == VR_RANGE))
1797 /* A range and an anti-range will cancel each other only if
1798 their ends are the same. For instance, in the example above,
1799 p_8's range ~[0, 0] and p_6's range [0, 0] are incompatible,
1800 so VR_P should be set to VR_VARYING. */
1801 if (compare_values (var_vr->min, vr_p->min) == 0
1802 && compare_values (var_vr->max, vr_p->max) == 0)
1803 set_value_range_to_varying (vr_p);
1806 tree min, max, anti_min, anti_max, real_min, real_max;
1809 /* We want to compute the logical AND of the two ranges;
1810 there are three cases to consider.
1813 1. The VR_ANTI_RANGE range is completely within the
1814 VR_RANGE and the endpoints of the ranges are
1815 different. In that case the resulting range
1816 should be whichever range is more precise.
1817 Typically that will be the VR_RANGE.
1819 2. The VR_ANTI_RANGE is completely disjoint from
1820 the VR_RANGE. In this case the resulting range
1821 should be the VR_RANGE.
1823 3. There is some overlap between the VR_ANTI_RANGE
1826 3a. If the high limit of the VR_ANTI_RANGE resides
1827 within the VR_RANGE, then the result is a new
1828 VR_RANGE starting at the high limit of the
1829 VR_ANTI_RANGE + 1 and extending to the
1830 high limit of the original VR_RANGE.
1832 3b. If the low limit of the VR_ANTI_RANGE resides
1833 within the VR_RANGE, then the result is a new
1834 VR_RANGE starting at the low limit of the original
1835 VR_RANGE and extending to the low limit of the
1836 VR_ANTI_RANGE - 1. */
1837 if (vr_p->type == VR_ANTI_RANGE)
1839 anti_min = vr_p->min;
1840 anti_max = vr_p->max;
1841 real_min = var_vr->min;
1842 real_max = var_vr->max;
1846 anti_min = var_vr->min;
1847 anti_max = var_vr->max;
1848 real_min = vr_p->min;
1849 real_max = vr_p->max;
1853 /* Case 1, VR_ANTI_RANGE completely within VR_RANGE,
1854 not including any endpoints. */
1855 if (compare_values (anti_max, real_max) == -1
1856 && compare_values (anti_min, real_min) == 1)
1858 /* If the range is covering the whole valid range of
1859 the type keep the anti-range. */
1860 if (!vrp_val_is_min (real_min)
1861 || !vrp_val_is_max (real_max))
1862 set_value_range (vr_p, VR_RANGE, real_min,
1863 real_max, vr_p->equiv);
1865 /* Case 2, VR_ANTI_RANGE completely disjoint from
1867 else if (compare_values (anti_min, real_max) == 1
1868 || compare_values (anti_max, real_min) == -1)
1870 set_value_range (vr_p, VR_RANGE, real_min,
1871 real_max, vr_p->equiv);
1873 /* Case 3a, the anti-range extends into the low
1874 part of the real range. Thus creating a new
1875 low for the real range. */
1876 else if (((cmp = compare_values (anti_max, real_min)) == 1
1878 && compare_values (anti_max, real_max) == -1)
1880 gcc_assert (!is_positive_overflow_infinity (anti_max));
1881 if (needs_overflow_infinity (TREE_TYPE (anti_max))
1882 && vrp_val_is_max (anti_max))
1884 if (!supports_overflow_infinity (TREE_TYPE (var_vr->min)))
1886 set_value_range_to_varying (vr_p);
1889 min = positive_overflow_infinity (TREE_TYPE (var_vr->min));
1891 else if (!POINTER_TYPE_P (TREE_TYPE (var_vr->min)))
1892 min = fold_build2 (PLUS_EXPR, TREE_TYPE (var_vr->min),
1894 build_int_cst (TREE_TYPE (var_vr->min), 1));
1896 min = fold_build_pointer_plus_hwi (anti_max, 1);
1898 set_value_range (vr_p, VR_RANGE, min, max, vr_p->equiv);
1900 /* Case 3b, the anti-range extends into the high
1901 part of the real range. Thus creating a new
1902 higher for the real range. */
1903 else if (compare_values (anti_min, real_min) == 1
1904 && ((cmp = compare_values (anti_min, real_max)) == -1
1907 gcc_assert (!is_negative_overflow_infinity (anti_min));
1908 if (needs_overflow_infinity (TREE_TYPE (anti_min))
1909 && vrp_val_is_min (anti_min))
1911 if (!supports_overflow_infinity (TREE_TYPE (var_vr->min)))
1913 set_value_range_to_varying (vr_p);
1916 max = negative_overflow_infinity (TREE_TYPE (var_vr->min));
1918 else if (!POINTER_TYPE_P (TREE_TYPE (var_vr->min)))
1919 max = fold_build2 (MINUS_EXPR, TREE_TYPE (var_vr->min),
1921 build_int_cst (TREE_TYPE (var_vr->min), 1));
1923 max = fold_build_pointer_plus_hwi (anti_min, -1);
1925 set_value_range (vr_p, VR_RANGE, min, max, vr_p->equiv);
1932 /* Extract range information from SSA name VAR and store it in VR. If
1933 VAR has an interesting range, use it. Otherwise, create the
1934 range [VAR, VAR] and return it. This is useful in situations where
1935 we may have conditionals testing values of VARYING names. For
1942 Even if y_5 is deemed VARYING, we can determine that x_3 > y_5 is
1946 extract_range_from_ssa_name (value_range_t *vr, tree var)
1948 value_range_t *var_vr = get_value_range (var);
1950 if (var_vr->type != VR_UNDEFINED && var_vr->type != VR_VARYING)
1951 copy_value_range (vr, var_vr);
1953 set_value_range (vr, VR_RANGE, var, var, NULL);
1955 add_equivalence (&vr->equiv, var);
1959 /* Wrapper around int_const_binop. If the operation overflows and we
1960 are not using wrapping arithmetic, then adjust the result to be
1961 -INF or +INF depending on CODE, VAL1 and VAL2. This can return
1962 NULL_TREE if we need to use an overflow infinity representation but
1963 the type does not support it. */
1966 vrp_int_const_binop (enum tree_code code, tree val1, tree val2)
1970 res = int_const_binop (code, val1, val2);
1972 /* If we are using unsigned arithmetic, operate symbolically
1973 on -INF and +INF as int_const_binop only handles signed overflow. */
1974 if (TYPE_UNSIGNED (TREE_TYPE (val1)))
1976 int checkz = compare_values (res, val1);
1977 bool overflow = false;
1979 /* Ensure that res = val1 [+*] val2 >= val1
1980 or that res = val1 - val2 <= val1. */
1981 if ((code == PLUS_EXPR
1982 && !(checkz == 1 || checkz == 0))
1983 || (code == MINUS_EXPR
1984 && !(checkz == 0 || checkz == -1)))
1988 /* Checking for multiplication overflow is done by dividing the
1989 output of the multiplication by the first input of the
1990 multiplication. If the result of that division operation is
1991 not equal to the second input of the multiplication, then the
1992 multiplication overflowed. */
1993 else if (code == MULT_EXPR && !integer_zerop (val1))
1995 tree tmp = int_const_binop (TRUNC_DIV_EXPR,
1998 int check = compare_values (tmp, val2);
2006 res = copy_node (res);
2007 TREE_OVERFLOW (res) = 1;
2011 else if (TYPE_OVERFLOW_WRAPS (TREE_TYPE (val1)))
2012 /* If the singed operation wraps then int_const_binop has done
2013 everything we want. */
2015 else if ((TREE_OVERFLOW (res)
2016 && !TREE_OVERFLOW (val1)
2017 && !TREE_OVERFLOW (val2))
2018 || is_overflow_infinity (val1)
2019 || is_overflow_infinity (val2))
2021 /* If the operation overflowed but neither VAL1 nor VAL2 are
2022 overflown, return -INF or +INF depending on the operation
2023 and the combination of signs of the operands. */
2024 int sgn1 = tree_int_cst_sgn (val1);
2025 int sgn2 = tree_int_cst_sgn (val2);
2027 if (needs_overflow_infinity (TREE_TYPE (res))
2028 && !supports_overflow_infinity (TREE_TYPE (res)))
2031 /* We have to punt on adding infinities of different signs,
2032 since we can't tell what the sign of the result should be.
2033 Likewise for subtracting infinities of the same sign. */
2034 if (((code == PLUS_EXPR && sgn1 != sgn2)
2035 || (code == MINUS_EXPR && sgn1 == sgn2))
2036 && is_overflow_infinity (val1)
2037 && is_overflow_infinity (val2))
2040 /* Don't try to handle division or shifting of infinities. */
2041 if ((code == TRUNC_DIV_EXPR
2042 || code == FLOOR_DIV_EXPR
2043 || code == CEIL_DIV_EXPR
2044 || code == EXACT_DIV_EXPR
2045 || code == ROUND_DIV_EXPR
2046 || code == RSHIFT_EXPR)
2047 && (is_overflow_infinity (val1)
2048 || is_overflow_infinity (val2)))
2051 /* Notice that we only need to handle the restricted set of
2052 operations handled by extract_range_from_binary_expr.
2053 Among them, only multiplication, addition and subtraction
2054 can yield overflow without overflown operands because we
2055 are working with integral types only... except in the
2056 case VAL1 = -INF and VAL2 = -1 which overflows to +INF
2057 for division too. */
2059 /* For multiplication, the sign of the overflow is given
2060 by the comparison of the signs of the operands. */
2061 if ((code == MULT_EXPR && sgn1 == sgn2)
2062 /* For addition, the operands must be of the same sign
2063 to yield an overflow. Its sign is therefore that
2064 of one of the operands, for example the first. For
2065 infinite operands X + -INF is negative, not positive. */
2066 || (code == PLUS_EXPR
2068 ? !is_negative_overflow_infinity (val2)
2069 : is_positive_overflow_infinity (val2)))
2070 /* For subtraction, non-infinite operands must be of
2071 different signs to yield an overflow. Its sign is
2072 therefore that of the first operand or the opposite of
2073 that of the second operand. A first operand of 0 counts
2074 as positive here, for the corner case 0 - (-INF), which
2075 overflows, but must yield +INF. For infinite operands 0
2076 - INF is negative, not positive. */
2077 || (code == MINUS_EXPR
2079 ? !is_positive_overflow_infinity (val2)
2080 : is_negative_overflow_infinity (val2)))
2081 /* We only get in here with positive shift count, so the
2082 overflow direction is the same as the sign of val1.
2083 Actually rshift does not overflow at all, but we only
2084 handle the case of shifting overflowed -INF and +INF. */
2085 || (code == RSHIFT_EXPR
2087 /* For division, the only case is -INF / -1 = +INF. */
2088 || code == TRUNC_DIV_EXPR
2089 || code == FLOOR_DIV_EXPR
2090 || code == CEIL_DIV_EXPR
2091 || code == EXACT_DIV_EXPR
2092 || code == ROUND_DIV_EXPR)
2093 return (needs_overflow_infinity (TREE_TYPE (res))
2094 ? positive_overflow_infinity (TREE_TYPE (res))
2095 : TYPE_MAX_VALUE (TREE_TYPE (res)));
2097 return (needs_overflow_infinity (TREE_TYPE (res))
2098 ? negative_overflow_infinity (TREE_TYPE (res))
2099 : TYPE_MIN_VALUE (TREE_TYPE (res)));
2106 /* For range VR compute two double_int bitmasks. In *MAY_BE_NONZERO
2107 bitmask if some bit is unset, it means for all numbers in the range
2108 the bit is 0, otherwise it might be 0 or 1. In *MUST_BE_NONZERO
2109 bitmask if some bit is set, it means for all numbers in the range
2110 the bit is 1, otherwise it might be 0 or 1. */
2113 zero_nonzero_bits_from_vr (value_range_t *vr, double_int *may_be_nonzero,
2114 double_int *must_be_nonzero)
2116 if (range_int_cst_p (vr))
2118 if (range_int_cst_singleton_p (vr))
2120 *may_be_nonzero = tree_to_double_int (vr->min);
2121 *must_be_nonzero = *may_be_nonzero;
2124 if (tree_int_cst_sgn (vr->min) >= 0)
2126 double_int dmin = tree_to_double_int (vr->min);
2127 double_int dmax = tree_to_double_int (vr->max);
2128 double_int xor_mask = double_int_xor (dmin, dmax);
2129 *may_be_nonzero = double_int_ior (dmin, dmax);
2130 *must_be_nonzero = double_int_and (dmin, dmax);
2131 if (xor_mask.high != 0)
2133 unsigned HOST_WIDE_INT mask
2134 = ((unsigned HOST_WIDE_INT) 1
2135 << floor_log2 (xor_mask.high)) - 1;
2136 may_be_nonzero->low = ALL_ONES;
2137 may_be_nonzero->high |= mask;
2138 must_be_nonzero->low = 0;
2139 must_be_nonzero->high &= ~mask;
2141 else if (xor_mask.low != 0)
2143 unsigned HOST_WIDE_INT mask
2144 = ((unsigned HOST_WIDE_INT) 1
2145 << floor_log2 (xor_mask.low)) - 1;
2146 may_be_nonzero->low |= mask;
2147 must_be_nonzero->low &= ~mask;
2152 may_be_nonzero->low = ALL_ONES;
2153 may_be_nonzero->high = ALL_ONES;
2154 must_be_nonzero->low = 0;
2155 must_be_nonzero->high = 0;
2160 /* Extract range information from a binary expression EXPR based on
2161 the ranges of each of its operands and the expression code. */
2164 extract_range_from_binary_expr (value_range_t *vr,
2165 enum tree_code code,
2166 tree expr_type, tree op0, tree op1)
2168 enum value_range_type type;
2171 value_range_t vr0 = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
2172 value_range_t vr1 = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
2174 /* Not all binary expressions can be applied to ranges in a
2175 meaningful way. Handle only arithmetic operations. */
2176 if (code != PLUS_EXPR
2177 && code != MINUS_EXPR
2178 && code != POINTER_PLUS_EXPR
2179 && code != MULT_EXPR
2180 && code != TRUNC_DIV_EXPR
2181 && code != FLOOR_DIV_EXPR
2182 && code != CEIL_DIV_EXPR
2183 && code != EXACT_DIV_EXPR
2184 && code != ROUND_DIV_EXPR
2185 && code != TRUNC_MOD_EXPR
2186 && code != RSHIFT_EXPR
2189 && code != BIT_AND_EXPR
2190 && code != BIT_IOR_EXPR
2191 && code != TRUTH_AND_EXPR
2192 && code != TRUTH_OR_EXPR)
2194 /* We can still do constant propagation here. */
2195 tree const_op0 = op_with_constant_singleton_value_range (op0);
2196 tree const_op1 = op_with_constant_singleton_value_range (op1);
2197 if (const_op0 || const_op1)
2199 tree tem = fold_binary (code, expr_type,
2200 const_op0 ? const_op0 : op0,
2201 const_op1 ? const_op1 : op1);
2203 && is_gimple_min_invariant (tem)
2204 && !is_overflow_infinity (tem))
2206 set_value_range (vr, VR_RANGE, tem, tem, NULL);
2210 set_value_range_to_varying (vr);
2214 /* Get value ranges for each operand. For constant operands, create
2215 a new value range with the operand to simplify processing. */
2216 if (TREE_CODE (op0) == SSA_NAME)
2217 vr0 = *(get_value_range (op0));
2218 else if (is_gimple_min_invariant (op0))
2219 set_value_range_to_value (&vr0, op0, NULL);
2221 set_value_range_to_varying (&vr0);
2223 if (TREE_CODE (op1) == SSA_NAME)
2224 vr1 = *(get_value_range (op1));
2225 else if (is_gimple_min_invariant (op1))
2226 set_value_range_to_value (&vr1, op1, NULL);
2228 set_value_range_to_varying (&vr1);
2230 /* If either range is UNDEFINED, so is the result. */
2231 if (vr0.type == VR_UNDEFINED || vr1.type == VR_UNDEFINED)
2233 set_value_range_to_undefined (vr);
2237 /* The type of the resulting value range defaults to VR0.TYPE. */
2240 /* Refuse to operate on VARYING ranges, ranges of different kinds
2241 and symbolic ranges. As an exception, we allow BIT_AND_EXPR
2242 because we may be able to derive a useful range even if one of
2243 the operands is VR_VARYING or symbolic range. Similarly for
2244 divisions. TODO, we may be able to derive anti-ranges in
2246 if (code != BIT_AND_EXPR
2247 && code != TRUTH_AND_EXPR
2248 && code != TRUTH_OR_EXPR
2249 && code != TRUNC_DIV_EXPR
2250 && code != FLOOR_DIV_EXPR
2251 && code != CEIL_DIV_EXPR
2252 && code != EXACT_DIV_EXPR
2253 && code != ROUND_DIV_EXPR
2254 && code != TRUNC_MOD_EXPR
2255 && (vr0.type == VR_VARYING
2256 || vr1.type == VR_VARYING
2257 || vr0.type != vr1.type
2258 || symbolic_range_p (&vr0)
2259 || symbolic_range_p (&vr1)))
2261 set_value_range_to_varying (vr);
2265 /* Now evaluate the expression to determine the new range. */
2266 if (POINTER_TYPE_P (expr_type)
2267 || POINTER_TYPE_P (TREE_TYPE (op0))
2268 || POINTER_TYPE_P (TREE_TYPE (op1)))
2270 if (code == MIN_EXPR || code == MAX_EXPR)
2272 /* For MIN/MAX expressions with pointers, we only care about
2273 nullness, if both are non null, then the result is nonnull.
2274 If both are null, then the result is null. Otherwise they
2276 if (range_is_nonnull (&vr0) && range_is_nonnull (&vr1))
2277 set_value_range_to_nonnull (vr, expr_type);
2278 else if (range_is_null (&vr0) && range_is_null (&vr1))
2279 set_value_range_to_null (vr, expr_type);
2281 set_value_range_to_varying (vr);
2285 if (code == POINTER_PLUS_EXPR)
2287 /* For pointer types, we are really only interested in asserting
2288 whether the expression evaluates to non-NULL. */
2289 if (range_is_nonnull (&vr0) || range_is_nonnull (&vr1))
2290 set_value_range_to_nonnull (vr, expr_type);
2291 else if (range_is_null (&vr0) && range_is_null (&vr1))
2292 set_value_range_to_null (vr, expr_type);
2294 set_value_range_to_varying (vr);
2296 else if (code == BIT_AND_EXPR)
2298 /* For pointer types, we are really only interested in asserting
2299 whether the expression evaluates to non-NULL. */
2300 if (range_is_nonnull (&vr0) && range_is_nonnull (&vr1))
2301 set_value_range_to_nonnull (vr, expr_type);
2302 else if (range_is_null (&vr0) || range_is_null (&vr1))
2303 set_value_range_to_null (vr, expr_type);
2305 set_value_range_to_varying (vr);
2313 /* For integer ranges, apply the operation to each end of the
2314 range and see what we end up with. */
2315 if (code == TRUTH_AND_EXPR
2316 || code == TRUTH_OR_EXPR)
2318 /* If one of the operands is zero, we know that the whole
2319 expression evaluates zero. */
2320 if (code == TRUTH_AND_EXPR
2321 && ((vr0.type == VR_RANGE
2322 && integer_zerop (vr0.min)
2323 && integer_zerop (vr0.max))
2324 || (vr1.type == VR_RANGE
2325 && integer_zerop (vr1.min)
2326 && integer_zerop (vr1.max))))
2329 min = max = build_int_cst (expr_type, 0);
2331 /* If one of the operands is one, we know that the whole
2332 expression evaluates one. */
2333 else if (code == TRUTH_OR_EXPR
2334 && ((vr0.type == VR_RANGE
2335 && integer_onep (vr0.min)
2336 && integer_onep (vr0.max))
2337 || (vr1.type == VR_RANGE
2338 && integer_onep (vr1.min)
2339 && integer_onep (vr1.max))))
2342 min = max = build_int_cst (expr_type, 1);
2344 else if (vr0.type != VR_VARYING
2345 && vr1.type != VR_VARYING
2346 && vr0.type == vr1.type
2347 && !symbolic_range_p (&vr0)
2348 && !overflow_infinity_range_p (&vr0)
2349 && !symbolic_range_p (&vr1)
2350 && !overflow_infinity_range_p (&vr1))
2352 /* Boolean expressions cannot be folded with int_const_binop. */
2353 min = fold_binary (code, expr_type, vr0.min, vr1.min);
2354 max = fold_binary (code, expr_type, vr0.max, vr1.max);
2358 /* The result of a TRUTH_*_EXPR is always true or false. */
2359 set_value_range_to_truthvalue (vr, expr_type);
2363 else if (code == PLUS_EXPR
2365 || code == MAX_EXPR)
2367 /* If we have a PLUS_EXPR with two VR_ANTI_RANGEs, drop to
2368 VR_VARYING. It would take more effort to compute a precise
2369 range for such a case. For example, if we have op0 == 1 and
2370 op1 == -1 with their ranges both being ~[0,0], we would have
2371 op0 + op1 == 0, so we cannot claim that the sum is in ~[0,0].
2372 Note that we are guaranteed to have vr0.type == vr1.type at
2374 if (vr0.type == VR_ANTI_RANGE)
2376 if (code == PLUS_EXPR)
2378 set_value_range_to_varying (vr);
2381 /* For MIN_EXPR and MAX_EXPR with two VR_ANTI_RANGEs,
2382 the resulting VR_ANTI_RANGE is the same - intersection
2383 of the two ranges. */
2384 min = vrp_int_const_binop (MAX_EXPR, vr0.min, vr1.min);
2385 max = vrp_int_const_binop (MIN_EXPR, vr0.max, vr1.max);
2389 /* For operations that make the resulting range directly
2390 proportional to the original ranges, apply the operation to
2391 the same end of each range. */
2392 min = vrp_int_const_binop (code, vr0.min, vr1.min);
2393 max = vrp_int_const_binop (code, vr0.max, vr1.max);
2396 /* If both additions overflowed the range kind is still correct.
2397 This happens regularly with subtracting something in unsigned
2399 ??? See PR30318 for all the cases we do not handle. */
2400 if (code == PLUS_EXPR
2401 && (TREE_OVERFLOW (min) && !is_overflow_infinity (min))
2402 && (TREE_OVERFLOW (max) && !is_overflow_infinity (max)))
2404 min = build_int_cst_wide (TREE_TYPE (min),
2405 TREE_INT_CST_LOW (min),
2406 TREE_INT_CST_HIGH (min));
2407 max = build_int_cst_wide (TREE_TYPE (max),
2408 TREE_INT_CST_LOW (max),
2409 TREE_INT_CST_HIGH (max));
2412 else if (code == MULT_EXPR
2413 || code == TRUNC_DIV_EXPR
2414 || code == FLOOR_DIV_EXPR
2415 || code == CEIL_DIV_EXPR
2416 || code == EXACT_DIV_EXPR
2417 || code == ROUND_DIV_EXPR
2418 || code == RSHIFT_EXPR)
2424 /* If we have an unsigned MULT_EXPR with two VR_ANTI_RANGEs,
2425 drop to VR_VARYING. It would take more effort to compute a
2426 precise range for such a case. For example, if we have
2427 op0 == 65536 and op1 == 65536 with their ranges both being
2428 ~[0,0] on a 32-bit machine, we would have op0 * op1 == 0, so
2429 we cannot claim that the product is in ~[0,0]. Note that we
2430 are guaranteed to have vr0.type == vr1.type at this
2432 if (code == MULT_EXPR
2433 && vr0.type == VR_ANTI_RANGE
2434 && !TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (op0)))
2436 set_value_range_to_varying (vr);
2440 /* If we have a RSHIFT_EXPR with any shift values outside [0..prec-1],
2441 then drop to VR_VARYING. Outside of this range we get undefined
2442 behavior from the shift operation. We cannot even trust
2443 SHIFT_COUNT_TRUNCATED at this stage, because that applies to rtl
2444 shifts, and the operation at the tree level may be widened. */
2445 if (code == RSHIFT_EXPR)
2447 if (vr1.type == VR_ANTI_RANGE
2448 || !vrp_expr_computes_nonnegative (op1, &sop)
2450 (build_int_cst (TREE_TYPE (vr1.max),
2451 TYPE_PRECISION (expr_type) - 1),
2454 set_value_range_to_varying (vr);
2459 else if ((code == TRUNC_DIV_EXPR
2460 || code == FLOOR_DIV_EXPR
2461 || code == CEIL_DIV_EXPR
2462 || code == EXACT_DIV_EXPR
2463 || code == ROUND_DIV_EXPR)
2464 && (vr0.type != VR_RANGE || symbolic_range_p (&vr0)))
2466 /* For division, if op1 has VR_RANGE but op0 does not, something
2467 can be deduced just from that range. Say [min, max] / [4, max]
2468 gives [min / 4, max / 4] range. */
2469 if (vr1.type == VR_RANGE
2470 && !symbolic_range_p (&vr1)
2471 && !range_includes_zero_p (&vr1))
2473 vr0.type = type = VR_RANGE;
2474 vr0.min = vrp_val_min (TREE_TYPE (op0));
2475 vr0.max = vrp_val_max (TREE_TYPE (op1));
2479 set_value_range_to_varying (vr);
2484 /* For divisions, if flag_non_call_exceptions is true, we must
2485 not eliminate a division by zero. */
2486 if ((code == TRUNC_DIV_EXPR
2487 || code == FLOOR_DIV_EXPR
2488 || code == CEIL_DIV_EXPR
2489 || code == EXACT_DIV_EXPR
2490 || code == ROUND_DIV_EXPR)
2491 && cfun->can_throw_non_call_exceptions
2492 && (vr1.type != VR_RANGE
2493 || symbolic_range_p (&vr1)
2494 || range_includes_zero_p (&vr1)))
2496 set_value_range_to_varying (vr);
2500 /* For divisions, if op0 is VR_RANGE, we can deduce a range
2501 even if op1 is VR_VARYING, VR_ANTI_RANGE, symbolic or can
2503 if ((code == TRUNC_DIV_EXPR
2504 || code == FLOOR_DIV_EXPR
2505 || code == CEIL_DIV_EXPR
2506 || code == EXACT_DIV_EXPR
2507 || code == ROUND_DIV_EXPR)
2508 && vr0.type == VR_RANGE
2509 && (vr1.type != VR_RANGE
2510 || symbolic_range_p (&vr1)
2511 || range_includes_zero_p (&vr1)))
2513 tree zero = build_int_cst (TREE_TYPE (vr0.min), 0);
2519 if (vrp_expr_computes_nonnegative (op1, &sop) && !sop)
2521 /* For unsigned division or when divisor is known
2522 to be non-negative, the range has to cover
2523 all numbers from 0 to max for positive max
2524 and all numbers from min to 0 for negative min. */
2525 cmp = compare_values (vr0.max, zero);
2528 else if (cmp == 0 || cmp == 1)
2532 cmp = compare_values (vr0.min, zero);
2535 else if (cmp == 0 || cmp == -1)
2542 /* Otherwise the range is -max .. max or min .. -min
2543 depending on which bound is bigger in absolute value,
2544 as the division can change the sign. */
2545 abs_extent_range (vr, vr0.min, vr0.max);
2548 if (type == VR_VARYING)
2550 set_value_range_to_varying (vr);
2555 /* Multiplications and divisions are a bit tricky to handle,
2556 depending on the mix of signs we have in the two ranges, we
2557 need to operate on different values to get the minimum and
2558 maximum values for the new range. One approach is to figure
2559 out all the variations of range combinations and do the
2562 However, this involves several calls to compare_values and it
2563 is pretty convoluted. It's simpler to do the 4 operations
2564 (MIN0 OP MIN1, MIN0 OP MAX1, MAX0 OP MIN1 and MAX0 OP MAX0 OP
2565 MAX1) and then figure the smallest and largest values to form
2569 gcc_assert ((vr0.type == VR_RANGE
2570 || (code == MULT_EXPR && vr0.type == VR_ANTI_RANGE))
2571 && vr0.type == vr1.type);
2573 /* Compute the 4 cross operations. */
2575 val[0] = vrp_int_const_binop (code, vr0.min, vr1.min);
2576 if (val[0] == NULL_TREE)
2579 if (vr1.max == vr1.min)
2583 val[1] = vrp_int_const_binop (code, vr0.min, vr1.max);
2584 if (val[1] == NULL_TREE)
2588 if (vr0.max == vr0.min)
2592 val[2] = vrp_int_const_binop (code, vr0.max, vr1.min);
2593 if (val[2] == NULL_TREE)
2597 if (vr0.min == vr0.max || vr1.min == vr1.max)
2601 val[3] = vrp_int_const_binop (code, vr0.max, vr1.max);
2602 if (val[3] == NULL_TREE)
2608 set_value_range_to_varying (vr);
2612 /* Set MIN to the minimum of VAL[i] and MAX to the maximum
2616 for (i = 1; i < 4; i++)
2618 if (!is_gimple_min_invariant (min)
2619 || (TREE_OVERFLOW (min) && !is_overflow_infinity (min))
2620 || !is_gimple_min_invariant (max)
2621 || (TREE_OVERFLOW (max) && !is_overflow_infinity (max)))
2626 if (!is_gimple_min_invariant (val[i])
2627 || (TREE_OVERFLOW (val[i])
2628 && !is_overflow_infinity (val[i])))
2630 /* If we found an overflowed value, set MIN and MAX
2631 to it so that we set the resulting range to
2637 if (compare_values (val[i], min) == -1)
2640 if (compare_values (val[i], max) == 1)
2646 else if (code == TRUNC_MOD_EXPR)
2649 if (vr1.type != VR_RANGE
2650 || symbolic_range_p (&vr1)
2651 || range_includes_zero_p (&vr1)
2652 || vrp_val_is_min (vr1.min))
2654 set_value_range_to_varying (vr);
2658 /* Compute MAX <|vr1.min|, |vr1.max|> - 1. */
2659 max = fold_unary_to_constant (ABS_EXPR, TREE_TYPE (vr1.min), vr1.min);
2660 if (tree_int_cst_lt (max, vr1.max))
2662 max = int_const_binop (MINUS_EXPR, max, integer_one_node);
2663 /* If the dividend is non-negative the modulus will be
2664 non-negative as well. */
2665 if (TYPE_UNSIGNED (TREE_TYPE (max))
2666 || (vrp_expr_computes_nonnegative (op0, &sop) && !sop))
2667 min = build_int_cst (TREE_TYPE (max), 0);
2669 min = fold_unary_to_constant (NEGATE_EXPR, TREE_TYPE (max), max);
2671 else if (code == MINUS_EXPR)
2673 /* If we have a MINUS_EXPR with two VR_ANTI_RANGEs, drop to
2674 VR_VARYING. It would take more effort to compute a precise
2675 range for such a case. For example, if we have op0 == 1 and
2676 op1 == 1 with their ranges both being ~[0,0], we would have
2677 op0 - op1 == 0, so we cannot claim that the difference is in
2678 ~[0,0]. Note that we are guaranteed to have
2679 vr0.type == vr1.type at this point. */
2680 if (vr0.type == VR_ANTI_RANGE)
2682 set_value_range_to_varying (vr);
2686 /* For MINUS_EXPR, apply the operation to the opposite ends of
2688 min = vrp_int_const_binop (code, vr0.min, vr1.max);
2689 max = vrp_int_const_binop (code, vr0.max, vr1.min);
2691 else if (code == BIT_AND_EXPR || code == BIT_IOR_EXPR)
2693 bool vr0_int_cst_singleton_p, vr1_int_cst_singleton_p;
2694 bool int_cst_range0, int_cst_range1;
2695 double_int may_be_nonzero0, may_be_nonzero1;
2696 double_int must_be_nonzero0, must_be_nonzero1;
2698 vr0_int_cst_singleton_p = range_int_cst_singleton_p (&vr0);
2699 vr1_int_cst_singleton_p = range_int_cst_singleton_p (&vr1);
2700 int_cst_range0 = zero_nonzero_bits_from_vr (&vr0, &may_be_nonzero0,
2702 int_cst_range1 = zero_nonzero_bits_from_vr (&vr1, &may_be_nonzero1,
2706 if (vr0_int_cst_singleton_p && vr1_int_cst_singleton_p)
2707 min = max = int_const_binop (code, vr0.max, vr1.max);
2708 else if (!int_cst_range0 && !int_cst_range1)
2710 set_value_range_to_varying (vr);
2713 else if (code == BIT_AND_EXPR)
2715 min = double_int_to_tree (expr_type,
2716 double_int_and (must_be_nonzero0,
2718 max = double_int_to_tree (expr_type,
2719 double_int_and (may_be_nonzero0,
2721 if (TREE_OVERFLOW (min) || tree_int_cst_sgn (min) < 0)
2723 if (TREE_OVERFLOW (max) || tree_int_cst_sgn (max) < 0)
2725 if (int_cst_range0 && tree_int_cst_sgn (vr0.min) >= 0)
2727 if (min == NULL_TREE)
2728 min = build_int_cst (expr_type, 0);
2729 if (max == NULL_TREE || tree_int_cst_lt (vr0.max, max))
2732 if (int_cst_range1 && tree_int_cst_sgn (vr1.min) >= 0)
2734 if (min == NULL_TREE)
2735 min = build_int_cst (expr_type, 0);
2736 if (max == NULL_TREE || tree_int_cst_lt (vr1.max, max))
2740 else if (!int_cst_range0
2742 || tree_int_cst_sgn (vr0.min) < 0
2743 || tree_int_cst_sgn (vr1.min) < 0)
2745 set_value_range_to_varying (vr);
2750 min = double_int_to_tree (expr_type,
2751 double_int_ior (must_be_nonzero0,
2753 max = double_int_to_tree (expr_type,
2754 double_int_ior (may_be_nonzero0,
2756 if (TREE_OVERFLOW (min) || tree_int_cst_sgn (min) < 0)
2759 min = vrp_int_const_binop (MAX_EXPR, min, vr0.min);
2760 if (TREE_OVERFLOW (max) || tree_int_cst_sgn (max) < 0)
2762 min = vrp_int_const_binop (MAX_EXPR, min, vr1.min);
2768 /* If either MIN or MAX overflowed, then set the resulting range to
2769 VARYING. But we do accept an overflow infinity
2771 if (min == NULL_TREE
2772 || !is_gimple_min_invariant (min)
2773 || (TREE_OVERFLOW (min) && !is_overflow_infinity (min))
2775 || !is_gimple_min_invariant (max)
2776 || (TREE_OVERFLOW (max) && !is_overflow_infinity (max)))
2778 set_value_range_to_varying (vr);
2784 2) [-INF, +-INF(OVF)]
2785 3) [+-INF(OVF), +INF]
2786 4) [+-INF(OVF), +-INF(OVF)]
2787 We learn nothing when we have INF and INF(OVF) on both sides.
2788 Note that we do accept [-INF, -INF] and [+INF, +INF] without
2790 if ((vrp_val_is_min (min) || is_overflow_infinity (min))
2791 && (vrp_val_is_max (max) || is_overflow_infinity (max)))
2793 set_value_range_to_varying (vr);
2797 cmp = compare_values (min, max);
2798 if (cmp == -2 || cmp == 1)
2800 /* If the new range has its limits swapped around (MIN > MAX),
2801 then the operation caused one of them to wrap around, mark
2802 the new range VARYING. */
2803 set_value_range_to_varying (vr);
2806 set_value_range (vr, type, min, max, NULL);
2810 /* Extract range information from a unary expression EXPR based on
2811 the range of its operand and the expression code. */
2814 extract_range_from_unary_expr (value_range_t *vr, enum tree_code code,
2815 tree type, tree op0)
2819 value_range_t vr0 = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
2821 /* Refuse to operate on certain unary expressions for which we
2822 cannot easily determine a resulting range. */
2823 if (code == FIX_TRUNC_EXPR
2824 || code == FLOAT_EXPR
2825 || code == BIT_NOT_EXPR
2826 || code == CONJ_EXPR)
2828 /* We can still do constant propagation here. */
2829 if ((op0 = op_with_constant_singleton_value_range (op0)) != NULL_TREE)
2831 tree tem = fold_unary (code, type, op0);
2833 && is_gimple_min_invariant (tem)
2834 && !is_overflow_infinity (tem))
2836 set_value_range (vr, VR_RANGE, tem, tem, NULL);
2840 set_value_range_to_varying (vr);
2844 /* Get value ranges for the operand. For constant operands, create
2845 a new value range with the operand to simplify processing. */
2846 if (TREE_CODE (op0) == SSA_NAME)
2847 vr0 = *(get_value_range (op0));
2848 else if (is_gimple_min_invariant (op0))
2849 set_value_range_to_value (&vr0, op0, NULL);
2851 set_value_range_to_varying (&vr0);
2853 /* If VR0 is UNDEFINED, so is the result. */
2854 if (vr0.type == VR_UNDEFINED)
2856 set_value_range_to_undefined (vr);
2860 /* Refuse to operate on symbolic ranges, or if neither operand is
2861 a pointer or integral type. */
2862 if ((!INTEGRAL_TYPE_P (TREE_TYPE (op0))
2863 && !POINTER_TYPE_P (TREE_TYPE (op0)))
2864 || (vr0.type != VR_VARYING
2865 && symbolic_range_p (&vr0)))
2867 set_value_range_to_varying (vr);
2871 /* If the expression involves pointers, we are only interested in
2872 determining if it evaluates to NULL [0, 0] or non-NULL (~[0, 0]). */
2873 if (POINTER_TYPE_P (type) || POINTER_TYPE_P (TREE_TYPE (op0)))
2878 if (range_is_nonnull (&vr0)
2879 || (tree_unary_nonzero_warnv_p (code, type, op0, &sop)
2881 set_value_range_to_nonnull (vr, type);
2882 else if (range_is_null (&vr0))
2883 set_value_range_to_null (vr, type);
2885 set_value_range_to_varying (vr);
2890 /* Handle unary expressions on integer ranges. */
2891 if (CONVERT_EXPR_CODE_P (code)
2892 && INTEGRAL_TYPE_P (type)
2893 && INTEGRAL_TYPE_P (TREE_TYPE (op0)))
2895 tree inner_type = TREE_TYPE (op0);
2896 tree outer_type = type;
2898 /* If VR0 is varying and we increase the type precision, assume
2899 a full range for the following transformation. */
2900 if (vr0.type == VR_VARYING
2901 && TYPE_PRECISION (inner_type) < TYPE_PRECISION (outer_type))
2903 vr0.type = VR_RANGE;
2904 vr0.min = TYPE_MIN_VALUE (inner_type);
2905 vr0.max = TYPE_MAX_VALUE (inner_type);
2908 /* If VR0 is a constant range or anti-range and the conversion is
2909 not truncating we can convert the min and max values and
2910 canonicalize the resulting range. Otherwise we can do the
2911 conversion if the size of the range is less than what the
2912 precision of the target type can represent and the range is
2913 not an anti-range. */
2914 if ((vr0.type == VR_RANGE
2915 || vr0.type == VR_ANTI_RANGE)
2916 && TREE_CODE (vr0.min) == INTEGER_CST
2917 && TREE_CODE (vr0.max) == INTEGER_CST
2918 && (!is_overflow_infinity (vr0.min)
2919 || (vr0.type == VR_RANGE
2920 && TYPE_PRECISION (outer_type) > TYPE_PRECISION (inner_type)
2921 && needs_overflow_infinity (outer_type)
2922 && supports_overflow_infinity (outer_type)))
2923 && (!is_overflow_infinity (vr0.max)
2924 || (vr0.type == VR_RANGE
2925 && TYPE_PRECISION (outer_type) > TYPE_PRECISION (inner_type)
2926 && needs_overflow_infinity (outer_type)
2927 && supports_overflow_infinity (outer_type)))
2928 && (TYPE_PRECISION (outer_type) >= TYPE_PRECISION (inner_type)
2929 || (vr0.type == VR_RANGE
2930 && integer_zerop (int_const_binop (RSHIFT_EXPR,
2931 int_const_binop (MINUS_EXPR, vr0.max, vr0.min),
2932 size_int (TYPE_PRECISION (outer_type)))))))
2934 tree new_min, new_max;
2935 new_min = force_fit_type_double (outer_type,
2936 tree_to_double_int (vr0.min),
2938 new_max = force_fit_type_double (outer_type,
2939 tree_to_double_int (vr0.max),
2941 if (is_overflow_infinity (vr0.min))
2942 new_min = negative_overflow_infinity (outer_type);
2943 if (is_overflow_infinity (vr0.max))
2944 new_max = positive_overflow_infinity (outer_type);
2945 set_and_canonicalize_value_range (vr, vr0.type,
2946 new_min, new_max, NULL);
2950 set_value_range_to_varying (vr);
2954 /* Conversion of a VR_VARYING value to a wider type can result
2955 in a usable range. So wait until after we've handled conversions
2956 before dropping the result to VR_VARYING if we had a source
2957 operand that is VR_VARYING. */
2958 if (vr0.type == VR_VARYING)
2960 set_value_range_to_varying (vr);
2964 /* Apply the operation to each end of the range and see what we end
2966 if (code == NEGATE_EXPR
2967 && !TYPE_UNSIGNED (type))
2969 /* NEGATE_EXPR flips the range around. We need to treat
2970 TYPE_MIN_VALUE specially. */
2971 if (is_positive_overflow_infinity (vr0.max))
2972 min = negative_overflow_infinity (type);
2973 else if (is_negative_overflow_infinity (vr0.max))
2974 min = positive_overflow_infinity (type);
2975 else if (!vrp_val_is_min (vr0.max))
2976 min = fold_unary_to_constant (code, type, vr0.max);
2977 else if (needs_overflow_infinity (type))
2979 if (supports_overflow_infinity (type)
2980 && !is_overflow_infinity (vr0.min)
2981 && !vrp_val_is_min (vr0.min))
2982 min = positive_overflow_infinity (type);
2985 set_value_range_to_varying (vr);
2990 min = TYPE_MIN_VALUE (type);
2992 if (is_positive_overflow_infinity (vr0.min))
2993 max = negative_overflow_infinity (type);
2994 else if (is_negative_overflow_infinity (vr0.min))
2995 max = positive_overflow_infinity (type);
2996 else if (!vrp_val_is_min (vr0.min))
2997 max = fold_unary_to_constant (code, type, vr0.min);
2998 else if (needs_overflow_infinity (type))
3000 if (supports_overflow_infinity (type))
3001 max = positive_overflow_infinity (type);
3004 set_value_range_to_varying (vr);
3009 max = TYPE_MIN_VALUE (type);
3011 else if (code == NEGATE_EXPR
3012 && TYPE_UNSIGNED (type))
3014 if (!range_includes_zero_p (&vr0))
3016 max = fold_unary_to_constant (code, type, vr0.min);
3017 min = fold_unary_to_constant (code, type, vr0.max);
3021 if (range_is_null (&vr0))
3022 set_value_range_to_null (vr, type);
3024 set_value_range_to_varying (vr);
3028 else if (code == ABS_EXPR
3029 && !TYPE_UNSIGNED (type))
3031 /* -TYPE_MIN_VALUE = TYPE_MIN_VALUE with flag_wrapv so we can't get a
3033 if (!TYPE_OVERFLOW_UNDEFINED (type)
3034 && ((vr0.type == VR_RANGE
3035 && vrp_val_is_min (vr0.min))
3036 || (vr0.type == VR_ANTI_RANGE
3037 && !vrp_val_is_min (vr0.min)
3038 && !range_includes_zero_p (&vr0))))
3040 set_value_range_to_varying (vr);
3044 /* ABS_EXPR may flip the range around, if the original range
3045 included negative values. */
3046 if (is_overflow_infinity (vr0.min))
3047 min = positive_overflow_infinity (type);
3048 else if (!vrp_val_is_min (vr0.min))
3049 min = fold_unary_to_constant (code, type, vr0.min);
3050 else if (!needs_overflow_infinity (type))
3051 min = TYPE_MAX_VALUE (type);
3052 else if (supports_overflow_infinity (type))
3053 min = positive_overflow_infinity (type);
3056 set_value_range_to_varying (vr);
3060 if (is_overflow_infinity (vr0.max))
3061 max = positive_overflow_infinity (type);
3062 else if (!vrp_val_is_min (vr0.max))
3063 max = fold_unary_to_constant (code, type, vr0.max);
3064 else if (!needs_overflow_infinity (type))
3065 max = TYPE_MAX_VALUE (type);
3066 else if (supports_overflow_infinity (type)
3067 /* We shouldn't generate [+INF, +INF] as set_value_range
3068 doesn't like this and ICEs. */
3069 && !is_positive_overflow_infinity (min))
3070 max = positive_overflow_infinity (type);
3073 set_value_range_to_varying (vr);
3077 cmp = compare_values (min, max);
3079 /* If a VR_ANTI_RANGEs contains zero, then we have
3080 ~[-INF, min(MIN, MAX)]. */
3081 if (vr0.type == VR_ANTI_RANGE)
3083 if (range_includes_zero_p (&vr0))
3085 /* Take the lower of the two values. */
3089 /* Create ~[-INF, min (abs(MIN), abs(MAX))]
3090 or ~[-INF + 1, min (abs(MIN), abs(MAX))] when
3091 flag_wrapv is set and the original anti-range doesn't include
3092 TYPE_MIN_VALUE, remember -TYPE_MIN_VALUE = TYPE_MIN_VALUE. */
3093 if (TYPE_OVERFLOW_WRAPS (type))
3095 tree type_min_value = TYPE_MIN_VALUE (type);
3097 min = (vr0.min != type_min_value
3098 ? int_const_binop (PLUS_EXPR, type_min_value,
3104 if (overflow_infinity_range_p (&vr0))
3105 min = negative_overflow_infinity (type);
3107 min = TYPE_MIN_VALUE (type);
3112 /* All else has failed, so create the range [0, INF], even for
3113 flag_wrapv since TYPE_MIN_VALUE is in the original
3115 vr0.type = VR_RANGE;
3116 min = build_int_cst (type, 0);
3117 if (needs_overflow_infinity (type))
3119 if (supports_overflow_infinity (type))
3120 max = positive_overflow_infinity (type);
3123 set_value_range_to_varying (vr);
3128 max = TYPE_MAX_VALUE (type);
3132 /* If the range contains zero then we know that the minimum value in the
3133 range will be zero. */
3134 else if (range_includes_zero_p (&vr0))
3138 min = build_int_cst (type, 0);
3142 /* If the range was reversed, swap MIN and MAX. */
3153 /* Otherwise, operate on each end of the range. */
3154 min = fold_unary_to_constant (code, type, vr0.min);
3155 max = fold_unary_to_constant (code, type, vr0.max);
3157 if (needs_overflow_infinity (type))
3159 gcc_assert (code != NEGATE_EXPR && code != ABS_EXPR);
3161 /* If both sides have overflowed, we don't know
3163 if ((is_overflow_infinity (vr0.min)
3164 || TREE_OVERFLOW (min))
3165 && (is_overflow_infinity (vr0.max)
3166 || TREE_OVERFLOW (max)))
3168 set_value_range_to_varying (vr);
3172 if (is_overflow_infinity (vr0.min))
3174 else if (TREE_OVERFLOW (min))
3176 if (supports_overflow_infinity (type))
3177 min = (tree_int_cst_sgn (min) >= 0
3178 ? positive_overflow_infinity (TREE_TYPE (min))
3179 : negative_overflow_infinity (TREE_TYPE (min)));
3182 set_value_range_to_varying (vr);
3187 if (is_overflow_infinity (vr0.max))
3189 else if (TREE_OVERFLOW (max))
3191 if (supports_overflow_infinity (type))
3192 max = (tree_int_cst_sgn (max) >= 0
3193 ? positive_overflow_infinity (TREE_TYPE (max))
3194 : negative_overflow_infinity (TREE_TYPE (max)));
3197 set_value_range_to_varying (vr);
3204 cmp = compare_values (min, max);
3205 if (cmp == -2 || cmp == 1)
3207 /* If the new range has its limits swapped around (MIN > MAX),
3208 then the operation caused one of them to wrap around, mark
3209 the new range VARYING. */
3210 set_value_range_to_varying (vr);
3213 set_value_range (vr, vr0.type, min, max, NULL);
3217 /* Extract range information from a conditional expression EXPR based on
3218 the ranges of each of its operands and the expression code. */
3221 extract_range_from_cond_expr (value_range_t *vr, tree expr)
3224 value_range_t vr0 = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
3225 value_range_t vr1 = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
3227 /* Get value ranges for each operand. For constant operands, create
3228 a new value range with the operand to simplify processing. */
3229 op0 = COND_EXPR_THEN (expr);
3230 if (TREE_CODE (op0) == SSA_NAME)
3231 vr0 = *(get_value_range (op0));
3232 else if (is_gimple_min_invariant (op0))
3233 set_value_range_to_value (&vr0, op0, NULL);
3235 set_value_range_to_varying (&vr0);
3237 op1 = COND_EXPR_ELSE (expr);
3238 if (TREE_CODE (op1) == SSA_NAME)
3239 vr1 = *(get_value_range (op1));
3240 else if (is_gimple_min_invariant (op1))
3241 set_value_range_to_value (&vr1, op1, NULL);
3243 set_value_range_to_varying (&vr1);
3245 /* The resulting value range is the union of the operand ranges */
3246 vrp_meet (&vr0, &vr1);
3247 copy_value_range (vr, &vr0);
3251 /* Extract range information from a comparison expression EXPR based
3252 on the range of its operand and the expression code. */
3255 extract_range_from_comparison (value_range_t *vr, enum tree_code code,
3256 tree type, tree op0, tree op1)
3261 val = vrp_evaluate_conditional_warnv_with_ops (code, op0, op1, false, &sop,
3264 /* A disadvantage of using a special infinity as an overflow
3265 representation is that we lose the ability to record overflow
3266 when we don't have an infinity. So we have to ignore a result
3267 which relies on overflow. */
3269 if (val && !is_overflow_infinity (val) && !sop)
3271 /* Since this expression was found on the RHS of an assignment,
3272 its type may be different from _Bool. Convert VAL to EXPR's
3274 val = fold_convert (type, val);
3275 if (is_gimple_min_invariant (val))
3276 set_value_range_to_value (vr, val, vr->equiv);
3278 set_value_range (vr, VR_RANGE, val, val, vr->equiv);
3281 /* The result of a comparison is always true or false. */
3282 set_value_range_to_truthvalue (vr, type);
3285 /* Try to derive a nonnegative or nonzero range out of STMT relying
3286 primarily on generic routines in fold in conjunction with range data.
3287 Store the result in *VR */
3290 extract_range_basic (value_range_t *vr, gimple stmt)
3293 tree type = gimple_expr_type (stmt);
3295 if (INTEGRAL_TYPE_P (type)
3296 && gimple_stmt_nonnegative_warnv_p (stmt, &sop))
3297 set_value_range_to_nonnegative (vr, type,
3298 sop || stmt_overflow_infinity (stmt));
3299 else if (vrp_stmt_computes_nonzero (stmt, &sop)
3301 set_value_range_to_nonnull (vr, type);
3303 set_value_range_to_varying (vr);
3307 /* Try to compute a useful range out of assignment STMT and store it
3311 extract_range_from_assignment (value_range_t *vr, gimple stmt)
3313 enum tree_code code = gimple_assign_rhs_code (stmt);
3315 if (code == ASSERT_EXPR)
3316 extract_range_from_assert (vr, gimple_assign_rhs1 (stmt));
3317 else if (code == SSA_NAME)
3318 extract_range_from_ssa_name (vr, gimple_assign_rhs1 (stmt));
3319 else if (TREE_CODE_CLASS (code) == tcc_binary
3320 || code == TRUTH_AND_EXPR
3321 || code == TRUTH_OR_EXPR
3322 || code == TRUTH_XOR_EXPR)
3323 extract_range_from_binary_expr (vr, gimple_assign_rhs_code (stmt),
3324 gimple_expr_type (stmt),
3325 gimple_assign_rhs1 (stmt),
3326 gimple_assign_rhs2 (stmt));
3327 else if (TREE_CODE_CLASS (code) == tcc_unary)
3328 extract_range_from_unary_expr (vr, gimple_assign_rhs_code (stmt),
3329 gimple_expr_type (stmt),
3330 gimple_assign_rhs1 (stmt));
3331 else if (code == COND_EXPR)
3332 extract_range_from_cond_expr (vr, gimple_assign_rhs1 (stmt));
3333 else if (TREE_CODE_CLASS (code) == tcc_comparison)
3334 extract_range_from_comparison (vr, gimple_assign_rhs_code (stmt),
3335 gimple_expr_type (stmt),
3336 gimple_assign_rhs1 (stmt),
3337 gimple_assign_rhs2 (stmt));
3338 else if (get_gimple_rhs_class (code) == GIMPLE_SINGLE_RHS
3339 && is_gimple_min_invariant (gimple_assign_rhs1 (stmt)))
3340 set_value_range_to_value (vr, gimple_assign_rhs1 (stmt), NULL);
3342 set_value_range_to_varying (vr);
3344 if (vr->type == VR_VARYING)
3345 extract_range_basic (vr, stmt);
3348 /* Given a range VR, a LOOP and a variable VAR, determine whether it
3349 would be profitable to adjust VR using scalar evolution information
3350 for VAR. If so, update VR with the new limits. */
3353 adjust_range_with_scev (value_range_t *vr, struct loop *loop,
3354 gimple stmt, tree var)
3356 tree init, step, chrec, tmin, tmax, min, max, type, tem;
3357 enum ev_direction dir;
3359 /* TODO. Don't adjust anti-ranges. An anti-range may provide
3360 better opportunities than a regular range, but I'm not sure. */
3361 if (vr->type == VR_ANTI_RANGE)
3364 chrec = instantiate_parameters (loop, analyze_scalar_evolution (loop, var));
3366 /* Like in PR19590, scev can return a constant function. */
3367 if (is_gimple_min_invariant (chrec))
3369 set_value_range_to_value (vr, chrec, vr->equiv);
3373 if (TREE_CODE (chrec) != POLYNOMIAL_CHREC)
3376 init = initial_condition_in_loop_num (chrec, loop->num);
3377 tem = op_with_constant_singleton_value_range (init);
3380 step = evolution_part_in_loop_num (chrec, loop->num);
3381 tem = op_with_constant_singleton_value_range (step);
3385 /* If STEP is symbolic, we can't know whether INIT will be the
3386 minimum or maximum value in the range. Also, unless INIT is
3387 a simple expression, compare_values and possibly other functions
3388 in tree-vrp won't be able to handle it. */
3389 if (step == NULL_TREE
3390 || !is_gimple_min_invariant (step)
3391 || !valid_value_p (init))
3394 dir = scev_direction (chrec);
3395 if (/* Do not adjust ranges if we do not know whether the iv increases
3396 or decreases, ... */
3397 dir == EV_DIR_UNKNOWN
3398 /* ... or if it may wrap. */
3399 || scev_probably_wraps_p (init, step, stmt, get_chrec_loop (chrec),
3403 /* We use TYPE_MIN_VALUE and TYPE_MAX_VALUE here instead of
3404 negative_overflow_infinity and positive_overflow_infinity,
3405 because we have concluded that the loop probably does not
3408 type = TREE_TYPE (var);
3409 if (POINTER_TYPE_P (type) || !TYPE_MIN_VALUE (type))
3410 tmin = lower_bound_in_type (type, type);
3412 tmin = TYPE_MIN_VALUE (type);
3413 if (POINTER_TYPE_P (type) || !TYPE_MAX_VALUE (type))
3414 tmax = upper_bound_in_type (type, type);
3416 tmax = TYPE_MAX_VALUE (type);
3418 /* Try to use estimated number of iterations for the loop to constrain the
3419 final value in the evolution. */
3420 if (TREE_CODE (step) == INTEGER_CST
3421 && is_gimple_val (init)
3422 && (TREE_CODE (init) != SSA_NAME
3423 || get_value_range (init)->type == VR_RANGE))
3427 if (estimated_loop_iterations (loop, true, &nit))
3429 value_range_t maxvr = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
3431 bool unsigned_p = TYPE_UNSIGNED (TREE_TYPE (step));
3434 dtmp = double_int_mul_with_sign (tree_to_double_int (step), nit,
3435 unsigned_p, &overflow);
3436 /* If the multiplication overflowed we can't do a meaningful
3437 adjustment. Likewise if the result doesn't fit in the type
3438 of the induction variable. For a signed type we have to
3439 check whether the result has the expected signedness which
3440 is that of the step as number of iterations is unsigned. */
3442 && double_int_fits_to_tree_p (TREE_TYPE (init), dtmp)
3444 || ((dtmp.high ^ TREE_INT_CST_HIGH (step)) >= 0)))
3446 tem = double_int_to_tree (TREE_TYPE (init), dtmp);
3447 extract_range_from_binary_expr (&maxvr, PLUS_EXPR,
3448 TREE_TYPE (init), init, tem);
3449 /* Likewise if the addition did. */
3450 if (maxvr.type == VR_RANGE)
3459 if (vr->type == VR_VARYING || vr->type == VR_UNDEFINED)
3464 /* For VARYING or UNDEFINED ranges, just about anything we get
3465 from scalar evolutions should be better. */
3467 if (dir == EV_DIR_DECREASES)
3472 /* If we would create an invalid range, then just assume we
3473 know absolutely nothing. This may be over-conservative,
3474 but it's clearly safe, and should happen only in unreachable
3475 parts of code, or for invalid programs. */
3476 if (compare_values (min, max) == 1)
3479 set_value_range (vr, VR_RANGE, min, max, vr->equiv);
3481 else if (vr->type == VR_RANGE)
3486 if (dir == EV_DIR_DECREASES)
3488 /* INIT is the maximum value. If INIT is lower than VR->MAX
3489 but no smaller than VR->MIN, set VR->MAX to INIT. */
3490 if (compare_values (init, max) == -1)
3493 /* According to the loop information, the variable does not
3494 overflow. If we think it does, probably because of an
3495 overflow due to arithmetic on a different INF value,
3497 if (is_negative_overflow_infinity (min)
3498 || compare_values (min, tmin) == -1)
3504 /* If INIT is bigger than VR->MIN, set VR->MIN to INIT. */
3505 if (compare_values (init, min) == 1)
3508 if (is_positive_overflow_infinity (max)
3509 || compare_values (tmax, max) == -1)
3513 /* If we just created an invalid range with the minimum
3514 greater than the maximum, we fail conservatively.
3515 This should happen only in unreachable
3516 parts of code, or for invalid programs. */
3517 if (compare_values (min, max) == 1)
3520 set_value_range (vr, VR_RANGE, min, max, vr->equiv);
3524 /* Return true if VAR may overflow at STMT. This checks any available
3525 loop information to see if we can determine that VAR does not
3529 vrp_var_may_overflow (tree var, gimple stmt)
3532 tree chrec, init, step;
3534 if (current_loops == NULL)
3537 l = loop_containing_stmt (stmt);
3542 chrec = instantiate_parameters (l, analyze_scalar_evolution (l, var));
3543 if (TREE_CODE (chrec) != POLYNOMIAL_CHREC)
3546 init = initial_condition_in_loop_num (chrec, l->num);
3547 step = evolution_part_in_loop_num (chrec, l->num);
3549 if (step == NULL_TREE
3550 || !is_gimple_min_invariant (step)
3551 || !valid_value_p (init))
3554 /* If we get here, we know something useful about VAR based on the
3555 loop information. If it wraps, it may overflow. */
3557 if (scev_probably_wraps_p (init, step, stmt, get_chrec_loop (chrec),
3561 if (dump_file && (dump_flags & TDF_DETAILS) != 0)
3563 print_generic_expr (dump_file, var, 0);
3564 fprintf (dump_file, ": loop information indicates does not overflow\n");
3571 /* Given two numeric value ranges VR0, VR1 and a comparison code COMP:
3573 - Return BOOLEAN_TRUE_NODE if VR0 COMP VR1 always returns true for
3574 all the values in the ranges.
3576 - Return BOOLEAN_FALSE_NODE if the comparison always returns false.
3578 - Return NULL_TREE if it is not always possible to determine the
3579 value of the comparison.
3581 Also set *STRICT_OVERFLOW_P to indicate whether a range with an
3582 overflow infinity was used in the test. */
3586 compare_ranges (enum tree_code comp, value_range_t *vr0, value_range_t *vr1,
3587 bool *strict_overflow_p)
3589 /* VARYING or UNDEFINED ranges cannot be compared. */
3590 if (vr0->type == VR_VARYING
3591 || vr0->type == VR_UNDEFINED
3592 || vr1->type == VR_VARYING
3593 || vr1->type == VR_UNDEFINED)
3596 /* Anti-ranges need to be handled separately. */
3597 if (vr0->type == VR_ANTI_RANGE || vr1->type == VR_ANTI_RANGE)
3599 /* If both are anti-ranges, then we cannot compute any
3601 if (vr0->type == VR_ANTI_RANGE && vr1->type == VR_ANTI_RANGE)
3604 /* These comparisons are never statically computable. */
3611 /* Equality can be computed only between a range and an
3612 anti-range. ~[VAL1, VAL2] == [VAL1, VAL2] is always false. */
3613 if (vr0->type == VR_RANGE)
3615 /* To simplify processing, make VR0 the anti-range. */
3616 value_range_t *tmp = vr0;
3621 gcc_assert (comp == NE_EXPR || comp == EQ_EXPR);
3623 if (compare_values_warnv (vr0->min, vr1->min, strict_overflow_p) == 0
3624 && compare_values_warnv (vr0->max, vr1->max, strict_overflow_p) == 0)
3625 return (comp == NE_EXPR) ? boolean_true_node : boolean_false_node;
3630 if (!usable_range_p (vr0, strict_overflow_p)
3631 || !usable_range_p (vr1, strict_overflow_p))
3634 /* Simplify processing. If COMP is GT_EXPR or GE_EXPR, switch the
3635 operands around and change the comparison code. */
3636 if (comp == GT_EXPR || comp == GE_EXPR)
3639 comp = (comp == GT_EXPR) ? LT_EXPR : LE_EXPR;
3645 if (comp == EQ_EXPR)
3647 /* Equality may only be computed if both ranges represent
3648 exactly one value. */
3649 if (compare_values_warnv (vr0->min, vr0->max, strict_overflow_p) == 0
3650 && compare_values_warnv (vr1->min, vr1->max, strict_overflow_p) == 0)
3652 int cmp_min = compare_values_warnv (vr0->min, vr1->min,
3654 int cmp_max = compare_values_warnv (vr0->max, vr1->max,
3656 if (cmp_min == 0 && cmp_max == 0)
3657 return boolean_true_node;
3658 else if (cmp_min != -2 && cmp_max != -2)
3659 return boolean_false_node;
3661 /* If [V0_MIN, V1_MAX] < [V1_MIN, V1_MAX] then V0 != V1. */
3662 else if (compare_values_warnv (vr0->min, vr1->max,
3663 strict_overflow_p) == 1
3664 || compare_values_warnv (vr1->min, vr0->max,
3665 strict_overflow_p) == 1)
3666 return boolean_false_node;
3670 else if (comp == NE_EXPR)
3674 /* If VR0 is completely to the left or completely to the right
3675 of VR1, they are always different. Notice that we need to
3676 make sure that both comparisons yield similar results to
3677 avoid comparing values that cannot be compared at
3679 cmp1 = compare_values_warnv (vr0->max, vr1->min, strict_overflow_p);
3680 cmp2 = compare_values_warnv (vr0->min, vr1->max, strict_overflow_p);
3681 if ((cmp1 == -1 && cmp2 == -1) || (cmp1 == 1 && cmp2 == 1))
3682 return boolean_true_node;
3684 /* If VR0 and VR1 represent a single value and are identical,
3686 else if (compare_values_warnv (vr0->min, vr0->max,
3687 strict_overflow_p) == 0
3688 && compare_values_warnv (vr1->min, vr1->max,
3689 strict_overflow_p) == 0
3690 && compare_values_warnv (vr0->min, vr1->min,
3691 strict_overflow_p) == 0
3692 && compare_values_warnv (vr0->max, vr1->max,
3693 strict_overflow_p) == 0)
3694 return boolean_false_node;
3696 /* Otherwise, they may or may not be different. */
3700 else if (comp == LT_EXPR || comp == LE_EXPR)
3704 /* If VR0 is to the left of VR1, return true. */
3705 tst = compare_values_warnv (vr0->max, vr1->min, strict_overflow_p);
3706 if ((comp == LT_EXPR && tst == -1)
3707 || (comp == LE_EXPR && (tst == -1 || tst == 0)))
3709 if (overflow_infinity_range_p (vr0)
3710 || overflow_infinity_range_p (vr1))
3711 *strict_overflow_p = true;
3712 return boolean_true_node;
3715 /* If VR0 is to the right of VR1, return false. */
3716 tst = compare_values_warnv (vr0->min, vr1->max, strict_overflow_p);
3717 if ((comp == LT_EXPR && (tst == 0 || tst == 1))
3718 || (comp == LE_EXPR && tst == 1))
3720 if (overflow_infinity_range_p (vr0)
3721 || overflow_infinity_range_p (vr1))
3722 *strict_overflow_p = true;
3723 return boolean_false_node;
3726 /* Otherwise, we don't know. */
3734 /* Given a value range VR, a value VAL and a comparison code COMP, return
3735 BOOLEAN_TRUE_NODE if VR COMP VAL always returns true for all the
3736 values in VR. Return BOOLEAN_FALSE_NODE if the comparison
3737 always returns false. Return NULL_TREE if it is not always
3738 possible to determine the value of the comparison. Also set
3739 *STRICT_OVERFLOW_P to indicate whether a range with an overflow
3740 infinity was used in the test. */
3743 compare_range_with_value (enum tree_code comp, value_range_t *vr, tree val,
3744 bool *strict_overflow_p)
3746 if (vr->type == VR_VARYING || vr->type == VR_UNDEFINED)
3749 /* Anti-ranges need to be handled separately. */
3750 if (vr->type == VR_ANTI_RANGE)
3752 /* For anti-ranges, the only predicates that we can compute at
3753 compile time are equality and inequality. */
3760 /* ~[VAL_1, VAL_2] OP VAL is known if VAL_1 <= VAL <= VAL_2. */
3761 if (value_inside_range (val, vr) == 1)
3762 return (comp == NE_EXPR) ? boolean_true_node : boolean_false_node;
3767 if (!usable_range_p (vr, strict_overflow_p))
3770 if (comp == EQ_EXPR)
3772 /* EQ_EXPR may only be computed if VR represents exactly
3774 if (compare_values_warnv (vr->min, vr->max, strict_overflow_p) == 0)
3776 int cmp = compare_values_warnv (vr->min, val, strict_overflow_p);
3778 return boolean_true_node;
3779 else if (cmp == -1 || cmp == 1 || cmp == 2)
3780 return boolean_false_node;
3782 else if (compare_values_warnv (val, vr->min, strict_overflow_p) == -1
3783 || compare_values_warnv (vr->max, val, strict_overflow_p) == -1)
3784 return boolean_false_node;
3788 else if (comp == NE_EXPR)
3790 /* If VAL is not inside VR, then they are always different. */
3791 if (compare_values_warnv (vr->max, val, strict_overflow_p) == -1
3792 || compare_values_warnv (vr->min, val, strict_overflow_p) == 1)
3793 return boolean_true_node;
3795 /* If VR represents exactly one value equal to VAL, then return
3797 if (compare_values_warnv (vr->min, vr->max, strict_overflow_p) == 0
3798 && compare_values_warnv (vr->min, val, strict_overflow_p) == 0)
3799 return boolean_false_node;
3801 /* Otherwise, they may or may not be different. */
3804 else if (comp == LT_EXPR || comp == LE_EXPR)
3808 /* If VR is to the left of VAL, return true. */
3809 tst = compare_values_warnv (vr->max, val, strict_overflow_p);
3810 if ((comp == LT_EXPR && tst == -1)
3811 || (comp == LE_EXPR && (tst == -1 || tst == 0)))
3813 if (overflow_infinity_range_p (vr))
3814 *strict_overflow_p = true;
3815 return boolean_true_node;
3818 /* If VR is to the right of VAL, return false. */
3819 tst = compare_values_warnv (vr->min, val, strict_overflow_p);
3820 if ((comp == LT_EXPR && (tst == 0 || tst == 1))
3821 || (comp == LE_EXPR && tst == 1))
3823 if (overflow_infinity_range_p (vr))
3824 *strict_overflow_p = true;
3825 return boolean_false_node;
3828 /* Otherwise, we don't know. */
3831 else if (comp == GT_EXPR || comp == GE_EXPR)
3835 /* If VR is to the right of VAL, return true. */
3836 tst = compare_values_warnv (vr->min, val, strict_overflow_p);
3837 if ((comp == GT_EXPR && tst == 1)
3838 || (comp == GE_EXPR && (tst == 0 || tst == 1)))
3840 if (overflow_infinity_range_p (vr))
3841 *strict_overflow_p = true;
3842 return boolean_true_node;
3845 /* If VR is to the left of VAL, return false. */
3846 tst = compare_values_warnv (vr->max, val, strict_overflow_p);
3847 if ((comp == GT_EXPR && (tst == -1 || tst == 0))
3848 || (comp == GE_EXPR && tst == -1))
3850 if (overflow_infinity_range_p (vr))
3851 *strict_overflow_p = true;
3852 return boolean_false_node;
3855 /* Otherwise, we don't know. */
3863 /* Debugging dumps. */
3865 void dump_value_range (FILE *, value_range_t *);
3866 void debug_value_range (value_range_t *);
3867 void dump_all_value_ranges (FILE *);
3868 void debug_all_value_ranges (void);
3869 void dump_vr_equiv (FILE *, bitmap);
3870 void debug_vr_equiv (bitmap);
3873 /* Dump value range VR to FILE. */
3876 dump_value_range (FILE *file, value_range_t *vr)
3879 fprintf (file, "[]");
3880 else if (vr->type == VR_UNDEFINED)
3881 fprintf (file, "UNDEFINED");
3882 else if (vr->type == VR_RANGE || vr->type == VR_ANTI_RANGE)
3884 tree type = TREE_TYPE (vr->min);
3886 fprintf (file, "%s[", (vr->type == VR_ANTI_RANGE) ? "~" : "");
3888 if (is_negative_overflow_infinity (vr->min))
3889 fprintf (file, "-INF(OVF)");
3890 else if (INTEGRAL_TYPE_P (type)
3891 && !TYPE_UNSIGNED (type)
3892 && vrp_val_is_min (vr->min))
3893 fprintf (file, "-INF");
3895 print_generic_expr (file, vr->min, 0);
3897 fprintf (file, ", ");
3899 if (is_positive_overflow_infinity (vr->max))
3900 fprintf (file, "+INF(OVF)");
3901 else if (INTEGRAL_TYPE_P (type)
3902 && vrp_val_is_max (vr->max))
3903 fprintf (file, "+INF");
3905 print_generic_expr (file, vr->max, 0);
3907 fprintf (file, "]");
3914 fprintf (file, " EQUIVALENCES: { ");
3916 EXECUTE_IF_SET_IN_BITMAP (vr->equiv, 0, i, bi)
3918 print_generic_expr (file, ssa_name (i), 0);
3919 fprintf (file, " ");
3923 fprintf (file, "} (%u elements)", c);
3926 else if (vr->type == VR_VARYING)
3927 fprintf (file, "VARYING");
3929 fprintf (file, "INVALID RANGE");
3933 /* Dump value range VR to stderr. */
3936 debug_value_range (value_range_t *vr)
3938 dump_value_range (stderr, vr);
3939 fprintf (stderr, "\n");
3943 /* Dump value ranges of all SSA_NAMEs to FILE. */
3946 dump_all_value_ranges (FILE *file)
3950 for (i = 0; i < num_vr_values; i++)
3954 print_generic_expr (file, ssa_name (i), 0);
3955 fprintf (file, ": ");
3956 dump_value_range (file, vr_value[i]);
3957 fprintf (file, "\n");
3961 fprintf (file, "\n");
3965 /* Dump all value ranges to stderr. */
3968 debug_all_value_ranges (void)
3970 dump_all_value_ranges (stderr);
3974 /* Given a COND_EXPR COND of the form 'V OP W', and an SSA name V,
3975 create a new SSA name N and return the assertion assignment
3976 'V = ASSERT_EXPR <V, V OP W>'. */
3979 build_assert_expr_for (tree cond, tree v)
3984 gcc_assert (TREE_CODE (v) == SSA_NAME);
3985 n = duplicate_ssa_name (v, NULL);
3987 if (COMPARISON_CLASS_P (cond))
3989 tree a = build2 (ASSERT_EXPR, TREE_TYPE (v), v, cond);
3990 assertion = gimple_build_assign (n, a);
3992 else if (TREE_CODE (cond) == TRUTH_NOT_EXPR)
3994 /* Given !V, build the assignment N = false. */
3995 tree op0 = TREE_OPERAND (cond, 0);
3996 gcc_assert (op0 == v);
3997 assertion = gimple_build_assign (n, boolean_false_node);
3999 else if (TREE_CODE (cond) == SSA_NAME)
4001 /* Given V, build the assignment N = true. */
4002 gcc_assert (v == cond);
4003 assertion = gimple_build_assign (n, boolean_true_node);
4008 SSA_NAME_DEF_STMT (n) = assertion;
4010 /* The new ASSERT_EXPR, creates a new SSA name that replaces the
4011 operand of the ASSERT_EXPR. Register the new name and the old one
4012 in the replacement table so that we can fix the SSA web after
4013 adding all the ASSERT_EXPRs. */
4014 register_new_name_mapping (n, v);
4020 /* Return false if EXPR is a predicate expression involving floating
4024 fp_predicate (gimple stmt)
4026 GIMPLE_CHECK (stmt, GIMPLE_COND);
4028 return FLOAT_TYPE_P (TREE_TYPE (gimple_cond_lhs (stmt)));
4032 /* If the range of values taken by OP can be inferred after STMT executes,
4033 return the comparison code (COMP_CODE_P) and value (VAL_P) that
4034 describes the inferred range. Return true if a range could be
4038 infer_value_range (gimple stmt, tree op, enum tree_code *comp_code_p, tree *val_p)
4041 *comp_code_p = ERROR_MARK;
4043 /* Do not attempt to infer anything in names that flow through
4045 if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (op))
4048 /* Similarly, don't infer anything from statements that may throw
4050 if (stmt_could_throw_p (stmt))
4053 /* If STMT is the last statement of a basic block with no
4054 successors, there is no point inferring anything about any of its
4055 operands. We would not be able to find a proper insertion point
4056 for the assertion, anyway. */
4057 if (stmt_ends_bb_p (stmt) && EDGE_COUNT (gimple_bb (stmt)->succs) == 0)
4060 /* We can only assume that a pointer dereference will yield
4061 non-NULL if -fdelete-null-pointer-checks is enabled. */
4062 if (flag_delete_null_pointer_checks
4063 && POINTER_TYPE_P (TREE_TYPE (op))
4064 && gimple_code (stmt) != GIMPLE_ASM)
4066 unsigned num_uses, num_loads, num_stores;
4068 count_uses_and_derefs (op, stmt, &num_uses, &num_loads, &num_stores);
4069 if (num_loads + num_stores > 0)
4071 *val_p = build_int_cst (TREE_TYPE (op), 0);
4072 *comp_code_p = NE_EXPR;
4081 void dump_asserts_for (FILE *, tree);
4082 void debug_asserts_for (tree);
4083 void dump_all_asserts (FILE *);
4084 void debug_all_asserts (void);
4086 /* Dump all the registered assertions for NAME to FILE. */
4089 dump_asserts_for (FILE *file, tree name)
4093 fprintf (file, "Assertions to be inserted for ");
4094 print_generic_expr (file, name, 0);
4095 fprintf (file, "\n");
4097 loc = asserts_for[SSA_NAME_VERSION (name)];
4100 fprintf (file, "\t");
4101 print_gimple_stmt (file, gsi_stmt (loc->si), 0, 0);
4102 fprintf (file, "\n\tBB #%d", loc->bb->index);
4105 fprintf (file, "\n\tEDGE %d->%d", loc->e->src->index,
4106 loc->e->dest->index);
4107 dump_edge_info (file, loc->e, 0);
4109 fprintf (file, "\n\tPREDICATE: ");
4110 print_generic_expr (file, name, 0);
4111 fprintf (file, " %s ", tree_code_name[(int)loc->comp_code]);
4112 print_generic_expr (file, loc->val, 0);
4113 fprintf (file, "\n\n");
4117 fprintf (file, "\n");
4121 /* Dump all the registered assertions for NAME to stderr. */
4124 debug_asserts_for (tree name)
4126 dump_asserts_for (stderr, name);
4130 /* Dump all the registered assertions for all the names to FILE. */
4133 dump_all_asserts (FILE *file)
4138 fprintf (file, "\nASSERT_EXPRs to be inserted\n\n");
4139 EXECUTE_IF_SET_IN_BITMAP (need_assert_for, 0, i, bi)
4140 dump_asserts_for (file, ssa_name (i));
4141 fprintf (file, "\n");
4145 /* Dump all the registered assertions for all the names to stderr. */
4148 debug_all_asserts (void)
4150 dump_all_asserts (stderr);
4154 /* If NAME doesn't have an ASSERT_EXPR registered for asserting
4155 'EXPR COMP_CODE VAL' at a location that dominates block BB or
4156 E->DEST, then register this location as a possible insertion point
4157 for ASSERT_EXPR <NAME, EXPR COMP_CODE VAL>.
4159 BB, E and SI provide the exact insertion point for the new
4160 ASSERT_EXPR. If BB is NULL, then the ASSERT_EXPR is to be inserted
4161 on edge E. Otherwise, if E is NULL, the ASSERT_EXPR is inserted on
4162 BB. If SI points to a COND_EXPR or a SWITCH_EXPR statement, then E
4163 must not be NULL. */
4166 register_new_assert_for (tree name, tree expr,
4167 enum tree_code comp_code,
4171 gimple_stmt_iterator si)
4173 assert_locus_t n, loc, last_loc;
4174 basic_block dest_bb;
4176 gcc_checking_assert (bb == NULL || e == NULL);
4179 gcc_checking_assert (gimple_code (gsi_stmt (si)) != GIMPLE_COND
4180 && gimple_code (gsi_stmt (si)) != GIMPLE_SWITCH);
4182 /* Never build an assert comparing against an integer constant with
4183 TREE_OVERFLOW set. This confuses our undefined overflow warning
4185 if (TREE_CODE (val) == INTEGER_CST
4186 && TREE_OVERFLOW (val))
4187 val = build_int_cst_wide (TREE_TYPE (val),
4188 TREE_INT_CST_LOW (val), TREE_INT_CST_HIGH (val));
4190 /* The new assertion A will be inserted at BB or E. We need to
4191 determine if the new location is dominated by a previously
4192 registered location for A. If we are doing an edge insertion,
4193 assume that A will be inserted at E->DEST. Note that this is not
4196 If E is a critical edge, it will be split. But even if E is
4197 split, the new block will dominate the same set of blocks that
4200 The reverse, however, is not true, blocks dominated by E->DEST
4201 will not be dominated by the new block created to split E. So,
4202 if the insertion location is on a critical edge, we will not use
4203 the new location to move another assertion previously registered
4204 at a block dominated by E->DEST. */
4205 dest_bb = (bb) ? bb : e->dest;
4207 /* If NAME already has an ASSERT_EXPR registered for COMP_CODE and
4208 VAL at a block dominating DEST_BB, then we don't need to insert a new
4209 one. Similarly, if the same assertion already exists at a block
4210 dominated by DEST_BB and the new location is not on a critical
4211 edge, then update the existing location for the assertion (i.e.,
4212 move the assertion up in the dominance tree).
4214 Note, this is implemented as a simple linked list because there
4215 should not be more than a handful of assertions registered per
4216 name. If this becomes a performance problem, a table hashed by
4217 COMP_CODE and VAL could be implemented. */
4218 loc = asserts_for[SSA_NAME_VERSION (name)];
4222 if (loc->comp_code == comp_code
4224 || operand_equal_p (loc->val, val, 0))
4225 && (loc->expr == expr
4226 || operand_equal_p (loc->expr, expr, 0)))
4228 /* If the assertion NAME COMP_CODE VAL has already been
4229 registered at a basic block that dominates DEST_BB, then
4230 we don't need to insert the same assertion again. Note
4231 that we don't check strict dominance here to avoid
4232 replicating the same assertion inside the same basic
4233 block more than once (e.g., when a pointer is
4234 dereferenced several times inside a block).
4236 An exception to this rule are edge insertions. If the
4237 new assertion is to be inserted on edge E, then it will
4238 dominate all the other insertions that we may want to
4239 insert in DEST_BB. So, if we are doing an edge
4240 insertion, don't do this dominance check. */
4242 && dominated_by_p (CDI_DOMINATORS, dest_bb, loc->bb))
4245 /* Otherwise, if E is not a critical edge and DEST_BB
4246 dominates the existing location for the assertion, move
4247 the assertion up in the dominance tree by updating its
4248 location information. */
4249 if ((e == NULL || !EDGE_CRITICAL_P (e))
4250 && dominated_by_p (CDI_DOMINATORS, loc->bb, dest_bb))
4259 /* Update the last node of the list and move to the next one. */
4264 /* If we didn't find an assertion already registered for
4265 NAME COMP_CODE VAL, add a new one at the end of the list of
4266 assertions associated with NAME. */
4267 n = XNEW (struct assert_locus_d);
4271 n->comp_code = comp_code;
4279 asserts_for[SSA_NAME_VERSION (name)] = n;
4281 bitmap_set_bit (need_assert_for, SSA_NAME_VERSION (name));
4284 /* (COND_OP0 COND_CODE COND_OP1) is a predicate which uses NAME.
4285 Extract a suitable test code and value and store them into *CODE_P and
4286 *VAL_P so the predicate is normalized to NAME *CODE_P *VAL_P.
4288 If no extraction was possible, return FALSE, otherwise return TRUE.
4290 If INVERT is true, then we invert the result stored into *CODE_P. */
4293 extract_code_and_val_from_cond_with_ops (tree name, enum tree_code cond_code,
4294 tree cond_op0, tree cond_op1,
4295 bool invert, enum tree_code *code_p,
4298 enum tree_code comp_code;
4301 /* Otherwise, we have a comparison of the form NAME COMP VAL
4302 or VAL COMP NAME. */
4303 if (name == cond_op1)
4305 /* If the predicate is of the form VAL COMP NAME, flip
4306 COMP around because we need to register NAME as the
4307 first operand in the predicate. */
4308 comp_code = swap_tree_comparison (cond_code);
4313 /* The comparison is of the form NAME COMP VAL, so the
4314 comparison code remains unchanged. */
4315 comp_code = cond_code;
4319 /* Invert the comparison code as necessary. */
4321 comp_code = invert_tree_comparison (comp_code, 0);
4323 /* VRP does not handle float types. */
4324 if (SCALAR_FLOAT_TYPE_P (TREE_TYPE (val)))
4327 /* Do not register always-false predicates.
4328 FIXME: this works around a limitation in fold() when dealing with
4329 enumerations. Given 'enum { N1, N2 } x;', fold will not
4330 fold 'if (x > N2)' to 'if (0)'. */
4331 if ((comp_code == GT_EXPR || comp_code == LT_EXPR)
4332 && INTEGRAL_TYPE_P (TREE_TYPE (val)))
4334 tree min = TYPE_MIN_VALUE (TREE_TYPE (val));
4335 tree max = TYPE_MAX_VALUE (TREE_TYPE (val));
4337 if (comp_code == GT_EXPR
4339 || compare_values (val, max) == 0))
4342 if (comp_code == LT_EXPR
4344 || compare_values (val, min) == 0))
4347 *code_p = comp_code;
4352 /* Try to register an edge assertion for SSA name NAME on edge E for
4353 the condition COND contributing to the conditional jump pointed to by BSI.
4354 Invert the condition COND if INVERT is true.
4355 Return true if an assertion for NAME could be registered. */
4358 register_edge_assert_for_2 (tree name, edge e, gimple_stmt_iterator bsi,
4359 enum tree_code cond_code,
4360 tree cond_op0, tree cond_op1, bool invert)
4363 enum tree_code comp_code;
4364 bool retval = false;
4366 if (!extract_code_and_val_from_cond_with_ops (name, cond_code,
4369 invert, &comp_code, &val))
4372 /* Only register an ASSERT_EXPR if NAME was found in the sub-graph
4373 reachable from E. */
4374 if (live_on_edge (e, name)
4375 && !has_single_use (name))
4377 register_new_assert_for (name, name, comp_code, val, NULL, e, bsi);
4381 /* In the case of NAME <= CST and NAME being defined as
4382 NAME = (unsigned) NAME2 + CST2 we can assert NAME2 >= -CST2
4383 and NAME2 <= CST - CST2. We can do the same for NAME > CST.
4384 This catches range and anti-range tests. */
4385 if ((comp_code == LE_EXPR
4386 || comp_code == GT_EXPR)
4387 && TREE_CODE (val) == INTEGER_CST
4388 && TYPE_UNSIGNED (TREE_TYPE (val)))
4390 gimple def_stmt = SSA_NAME_DEF_STMT (name);
4391 tree cst2 = NULL_TREE, name2 = NULL_TREE, name3 = NULL_TREE;
4393 /* Extract CST2 from the (optional) addition. */
4394 if (is_gimple_assign (def_stmt)
4395 && gimple_assign_rhs_code (def_stmt) == PLUS_EXPR)
4397 name2 = gimple_assign_rhs1 (def_stmt);
4398 cst2 = gimple_assign_rhs2 (def_stmt);
4399 if (TREE_CODE (name2) == SSA_NAME
4400 && TREE_CODE (cst2) == INTEGER_CST)
4401 def_stmt = SSA_NAME_DEF_STMT (name2);
4404 /* Extract NAME2 from the (optional) sign-changing cast. */
4405 if (gimple_assign_cast_p (def_stmt))
4407 if (CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (def_stmt))
4408 && ! TYPE_UNSIGNED (TREE_TYPE (gimple_assign_rhs1 (def_stmt)))
4409 && (TYPE_PRECISION (gimple_expr_type (def_stmt))
4410 == TYPE_PRECISION (TREE_TYPE (gimple_assign_rhs1 (def_stmt)))))
4411 name3 = gimple_assign_rhs1 (def_stmt);
4414 /* If name3 is used later, create an ASSERT_EXPR for it. */
4415 if (name3 != NULL_TREE
4416 && TREE_CODE (name3) == SSA_NAME
4417 && (cst2 == NULL_TREE
4418 || TREE_CODE (cst2) == INTEGER_CST)
4419 && INTEGRAL_TYPE_P (TREE_TYPE (name3))
4420 && live_on_edge (e, name3)
4421 && !has_single_use (name3))
4425 /* Build an expression for the range test. */
4426 tmp = build1 (NOP_EXPR, TREE_TYPE (name), name3);
4427 if (cst2 != NULL_TREE)
4428 tmp = build2 (PLUS_EXPR, TREE_TYPE (name), tmp, cst2);
4432 fprintf (dump_file, "Adding assert for ");
4433 print_generic_expr (dump_file, name3, 0);
4434 fprintf (dump_file, " from ");
4435 print_generic_expr (dump_file, tmp, 0);
4436 fprintf (dump_file, "\n");
4439 register_new_assert_for (name3, tmp, comp_code, val, NULL, e, bsi);
4444 /* If name2 is used later, create an ASSERT_EXPR for it. */
4445 if (name2 != NULL_TREE
4446 && TREE_CODE (name2) == SSA_NAME
4447 && TREE_CODE (cst2) == INTEGER_CST
4448 && INTEGRAL_TYPE_P (TREE_TYPE (name2))
4449 && live_on_edge (e, name2)
4450 && !has_single_use (name2))
4454 /* Build an expression for the range test. */
4456 if (TREE_TYPE (name) != TREE_TYPE (name2))
4457 tmp = build1 (NOP_EXPR, TREE_TYPE (name), tmp);
4458 if (cst2 != NULL_TREE)
4459 tmp = build2 (PLUS_EXPR, TREE_TYPE (name), tmp, cst2);
4463 fprintf (dump_file, "Adding assert for ");
4464 print_generic_expr (dump_file, name2, 0);
4465 fprintf (dump_file, " from ");
4466 print_generic_expr (dump_file, tmp, 0);
4467 fprintf (dump_file, "\n");
4470 register_new_assert_for (name2, tmp, comp_code, val, NULL, e, bsi);
4479 /* OP is an operand of a truth value expression which is known to have
4480 a particular value. Register any asserts for OP and for any
4481 operands in OP's defining statement.
4483 If CODE is EQ_EXPR, then we want to register OP is zero (false),
4484 if CODE is NE_EXPR, then we want to register OP is nonzero (true). */
4487 register_edge_assert_for_1 (tree op, enum tree_code code,
4488 edge e, gimple_stmt_iterator bsi)
4490 bool retval = false;
4493 enum tree_code rhs_code;
4495 /* We only care about SSA_NAMEs. */
4496 if (TREE_CODE (op) != SSA_NAME)
4499 /* We know that OP will have a zero or nonzero value. If OP is used
4500 more than once go ahead and register an assert for OP.
4502 The FOUND_IN_SUBGRAPH support is not helpful in this situation as
4503 it will always be set for OP (because OP is used in a COND_EXPR in
4505 if (!has_single_use (op))
4507 val = build_int_cst (TREE_TYPE (op), 0);
4508 register_new_assert_for (op, op, code, val, NULL, e, bsi);
4512 /* Now look at how OP is set. If it's set from a comparison,
4513 a truth operation or some bit operations, then we may be able
4514 to register information about the operands of that assignment. */
4515 op_def = SSA_NAME_DEF_STMT (op);
4516 if (gimple_code (op_def) != GIMPLE_ASSIGN)
4519 rhs_code = gimple_assign_rhs_code (op_def);
4521 if (TREE_CODE_CLASS (rhs_code) == tcc_comparison)
4523 bool invert = (code == EQ_EXPR ? true : false);
4524 tree op0 = gimple_assign_rhs1 (op_def);
4525 tree op1 = gimple_assign_rhs2 (op_def);
4527 if (TREE_CODE (op0) == SSA_NAME)
4528 retval |= register_edge_assert_for_2 (op0, e, bsi, rhs_code, op0, op1,
4530 if (TREE_CODE (op1) == SSA_NAME)
4531 retval |= register_edge_assert_for_2 (op1, e, bsi, rhs_code, op0, op1,
4534 else if ((code == NE_EXPR
4535 && (gimple_assign_rhs_code (op_def) == TRUTH_AND_EXPR
4536 || gimple_assign_rhs_code (op_def) == BIT_AND_EXPR))
4538 && (gimple_assign_rhs_code (op_def) == TRUTH_OR_EXPR
4539 || gimple_assign_rhs_code (op_def) == BIT_IOR_EXPR)))
4541 /* Recurse on each operand. */
4542 retval |= register_edge_assert_for_1 (gimple_assign_rhs1 (op_def),
4544 retval |= register_edge_assert_for_1 (gimple_assign_rhs2 (op_def),
4547 else if (gimple_assign_rhs_code (op_def) == TRUTH_NOT_EXPR)
4549 /* Recurse, flipping CODE. */
4550 code = invert_tree_comparison (code, false);
4551 retval |= register_edge_assert_for_1 (gimple_assign_rhs1 (op_def),
4554 else if (gimple_assign_rhs_code (op_def) == SSA_NAME)
4556 /* Recurse through the copy. */
4557 retval |= register_edge_assert_for_1 (gimple_assign_rhs1 (op_def),
4560 else if (CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (op_def)))
4562 /* Recurse through the type conversion. */
4563 retval |= register_edge_assert_for_1 (gimple_assign_rhs1 (op_def),
4570 /* Try to register an edge assertion for SSA name NAME on edge E for
4571 the condition COND contributing to the conditional jump pointed to by SI.
4572 Return true if an assertion for NAME could be registered. */
4575 register_edge_assert_for (tree name, edge e, gimple_stmt_iterator si,
4576 enum tree_code cond_code, tree cond_op0,
4580 enum tree_code comp_code;
4581 bool retval = false;
4582 bool is_else_edge = (e->flags & EDGE_FALSE_VALUE) != 0;
4584 /* Do not attempt to infer anything in names that flow through
4586 if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (name))
4589 if (!extract_code_and_val_from_cond_with_ops (name, cond_code,
4595 /* Register ASSERT_EXPRs for name. */
4596 retval |= register_edge_assert_for_2 (name, e, si, cond_code, cond_op0,
4597 cond_op1, is_else_edge);
4600 /* If COND is effectively an equality test of an SSA_NAME against
4601 the value zero or one, then we may be able to assert values
4602 for SSA_NAMEs which flow into COND. */
4604 /* In the case of NAME == 1 or NAME != 0, for TRUTH_AND_EXPR defining
4605 statement of NAME we can assert both operands of the TRUTH_AND_EXPR
4606 have nonzero value. */
4607 if (((comp_code == EQ_EXPR && integer_onep (val))
4608 || (comp_code == NE_EXPR && integer_zerop (val))))
4610 gimple def_stmt = SSA_NAME_DEF_STMT (name);
4612 if (is_gimple_assign (def_stmt)
4613 && (gimple_assign_rhs_code (def_stmt) == TRUTH_AND_EXPR
4614 || gimple_assign_rhs_code (def_stmt) == BIT_AND_EXPR))
4616 tree op0 = gimple_assign_rhs1 (def_stmt);
4617 tree op1 = gimple_assign_rhs2 (def_stmt);
4618 retval |= register_edge_assert_for_1 (op0, NE_EXPR, e, si);
4619 retval |= register_edge_assert_for_1 (op1, NE_EXPR, e, si);
4623 /* In the case of NAME == 0 or NAME != 1, for TRUTH_OR_EXPR defining
4624 statement of NAME we can assert both operands of the TRUTH_OR_EXPR
4626 if (((comp_code == EQ_EXPR && integer_zerop (val))
4627 || (comp_code == NE_EXPR && integer_onep (val))))
4629 gimple def_stmt = SSA_NAME_DEF_STMT (name);
4631 if (is_gimple_assign (def_stmt)
4632 && (gimple_assign_rhs_code (def_stmt) == TRUTH_OR_EXPR
4633 /* For BIT_IOR_EXPR only if NAME == 0 both operands have
4634 necessarily zero value. */
4635 || (comp_code == EQ_EXPR
4636 && (gimple_assign_rhs_code (def_stmt) == BIT_IOR_EXPR))))
4638 tree op0 = gimple_assign_rhs1 (def_stmt);
4639 tree op1 = gimple_assign_rhs2 (def_stmt);
4640 retval |= register_edge_assert_for_1 (op0, EQ_EXPR, e, si);
4641 retval |= register_edge_assert_for_1 (op1, EQ_EXPR, e, si);
4649 /* Determine whether the outgoing edges of BB should receive an
4650 ASSERT_EXPR for each of the operands of BB's LAST statement.
4651 The last statement of BB must be a COND_EXPR.
4653 If any of the sub-graphs rooted at BB have an interesting use of
4654 the predicate operands, an assert location node is added to the
4655 list of assertions for the corresponding operands. */
4658 find_conditional_asserts (basic_block bb, gimple last)
4661 gimple_stmt_iterator bsi;
4667 need_assert = false;
4668 bsi = gsi_for_stmt (last);
4670 /* Look for uses of the operands in each of the sub-graphs
4671 rooted at BB. We need to check each of the outgoing edges
4672 separately, so that we know what kind of ASSERT_EXPR to
4674 FOR_EACH_EDGE (e, ei, bb->succs)
4679 /* Register the necessary assertions for each operand in the
4680 conditional predicate. */
4681 FOR_EACH_SSA_TREE_OPERAND (op, last, iter, SSA_OP_USE)
4683 need_assert |= register_edge_assert_for (op, e, bsi,
4684 gimple_cond_code (last),
4685 gimple_cond_lhs (last),
4686 gimple_cond_rhs (last));
4699 /* Compare two case labels sorting first by the destination bb index
4700 and then by the case value. */
4703 compare_case_labels (const void *p1, const void *p2)
4705 const struct case_info *ci1 = (const struct case_info *) p1;
4706 const struct case_info *ci2 = (const struct case_info *) p2;
4707 int idx1 = ci1->bb->index;
4708 int idx2 = ci2->bb->index;
4712 else if (idx1 == idx2)
4714 /* Make sure the default label is first in a group. */
4715 if (!CASE_LOW (ci1->expr))
4717 else if (!CASE_LOW (ci2->expr))
4720 return tree_int_cst_compare (CASE_LOW (ci1->expr),
4721 CASE_LOW (ci2->expr));
4727 /* Determine whether the outgoing edges of BB should receive an
4728 ASSERT_EXPR for each of the operands of BB's LAST statement.
4729 The last statement of BB must be a SWITCH_EXPR.
4731 If any of the sub-graphs rooted at BB have an interesting use of
4732 the predicate operands, an assert location node is added to the
4733 list of assertions for the corresponding operands. */
4736 find_switch_asserts (basic_block bb, gimple last)
4739 gimple_stmt_iterator bsi;
4742 struct case_info *ci;
4743 size_t n = gimple_switch_num_labels (last);
4744 #if GCC_VERSION >= 4000
4747 /* Work around GCC 3.4 bug (PR 37086). */
4748 volatile unsigned int idx;
4751 need_assert = false;
4752 bsi = gsi_for_stmt (last);
4753 op = gimple_switch_index (last);
4754 if (TREE_CODE (op) != SSA_NAME)
4757 /* Build a vector of case labels sorted by destination label. */
4758 ci = XNEWVEC (struct case_info, n);
4759 for (idx = 0; idx < n; ++idx)
4761 ci[idx].expr = gimple_switch_label (last, idx);
4762 ci[idx].bb = label_to_block (CASE_LABEL (ci[idx].expr));
4764 qsort (ci, n, sizeof (struct case_info), compare_case_labels);
4766 for (idx = 0; idx < n; ++idx)
4769 tree cl = ci[idx].expr;
4770 basic_block cbb = ci[idx].bb;
4772 min = CASE_LOW (cl);
4773 max = CASE_HIGH (cl);
4775 /* If there are multiple case labels with the same destination
4776 we need to combine them to a single value range for the edge. */
4777 if (idx + 1 < n && cbb == ci[idx + 1].bb)
4779 /* Skip labels until the last of the group. */
4782 } while (idx < n && cbb == ci[idx].bb);
4785 /* Pick up the maximum of the case label range. */
4786 if (CASE_HIGH (ci[idx].expr))
4787 max = CASE_HIGH (ci[idx].expr);
4789 max = CASE_LOW (ci[idx].expr);
4792 /* Nothing to do if the range includes the default label until we
4793 can register anti-ranges. */
4794 if (min == NULL_TREE)
4797 /* Find the edge to register the assert expr on. */
4798 e = find_edge (bb, cbb);
4800 /* Register the necessary assertions for the operand in the
4802 need_assert |= register_edge_assert_for (op, e, bsi,
4803 max ? GE_EXPR : EQ_EXPR,
4805 fold_convert (TREE_TYPE (op),
4809 need_assert |= register_edge_assert_for (op, e, bsi, LE_EXPR,
4811 fold_convert (TREE_TYPE (op),
4821 /* Traverse all the statements in block BB looking for statements that
4822 may generate useful assertions for the SSA names in their operand.
4823 If a statement produces a useful assertion A for name N_i, then the
4824 list of assertions already generated for N_i is scanned to
4825 determine if A is actually needed.
4827 If N_i already had the assertion A at a location dominating the
4828 current location, then nothing needs to be done. Otherwise, the
4829 new location for A is recorded instead.
4831 1- For every statement S in BB, all the variables used by S are
4832 added to bitmap FOUND_IN_SUBGRAPH.
4834 2- If statement S uses an operand N in a way that exposes a known
4835 value range for N, then if N was not already generated by an
4836 ASSERT_EXPR, create a new assert location for N. For instance,
4837 if N is a pointer and the statement dereferences it, we can
4838 assume that N is not NULL.
4840 3- COND_EXPRs are a special case of #2. We can derive range
4841 information from the predicate but need to insert different
4842 ASSERT_EXPRs for each of the sub-graphs rooted at the
4843 conditional block. If the last statement of BB is a conditional
4844 expression of the form 'X op Y', then
4846 a) Remove X and Y from the set FOUND_IN_SUBGRAPH.
4848 b) If the conditional is the only entry point to the sub-graph
4849 corresponding to the THEN_CLAUSE, recurse into it. On
4850 return, if X and/or Y are marked in FOUND_IN_SUBGRAPH, then
4851 an ASSERT_EXPR is added for the corresponding variable.
4853 c) Repeat step (b) on the ELSE_CLAUSE.
4855 d) Mark X and Y in FOUND_IN_SUBGRAPH.
4864 In this case, an assertion on the THEN clause is useful to
4865 determine that 'a' is always 9 on that edge. However, an assertion
4866 on the ELSE clause would be unnecessary.
4868 4- If BB does not end in a conditional expression, then we recurse
4869 into BB's dominator children.
4871 At the end of the recursive traversal, every SSA name will have a
4872 list of locations where ASSERT_EXPRs should be added. When a new
4873 location for name N is found, it is registered by calling
4874 register_new_assert_for. That function keeps track of all the
4875 registered assertions to prevent adding unnecessary assertions.
4876 For instance, if a pointer P_4 is dereferenced more than once in a
4877 dominator tree, only the location dominating all the dereference of
4878 P_4 will receive an ASSERT_EXPR.
4880 If this function returns true, then it means that there are names
4881 for which we need to generate ASSERT_EXPRs. Those assertions are
4882 inserted by process_assert_insertions. */
4885 find_assert_locations_1 (basic_block bb, sbitmap live)
4887 gimple_stmt_iterator si;
4892 need_assert = false;
4893 last = last_stmt (bb);
4895 /* If BB's last statement is a conditional statement involving integer
4896 operands, determine if we need to add ASSERT_EXPRs. */
4898 && gimple_code (last) == GIMPLE_COND
4899 && !fp_predicate (last)
4900 && !ZERO_SSA_OPERANDS (last, SSA_OP_USE))
4901 need_assert |= find_conditional_asserts (bb, last);
4903 /* If BB's last statement is a switch statement involving integer
4904 operands, determine if we need to add ASSERT_EXPRs. */
4906 && gimple_code (last) == GIMPLE_SWITCH
4907 && !ZERO_SSA_OPERANDS (last, SSA_OP_USE))
4908 need_assert |= find_switch_asserts (bb, last);
4910 /* Traverse all the statements in BB marking used names and looking
4911 for statements that may infer assertions for their used operands. */
4912 for (si = gsi_start_bb (bb); !gsi_end_p (si); gsi_next (&si))
4918 stmt = gsi_stmt (si);
4920 if (is_gimple_debug (stmt))
4923 /* See if we can derive an assertion for any of STMT's operands. */
4924 FOR_EACH_SSA_TREE_OPERAND (op, stmt, i, SSA_OP_USE)
4927 enum tree_code comp_code;
4929 /* Mark OP in our live bitmap. */
4930 SET_BIT (live, SSA_NAME_VERSION (op));
4932 /* If OP is used in such a way that we can infer a value
4933 range for it, and we don't find a previous assertion for
4934 it, create a new assertion location node for OP. */
4935 if (infer_value_range (stmt, op, &comp_code, &value))
4937 /* If we are able to infer a nonzero value range for OP,
4938 then walk backwards through the use-def chain to see if OP
4939 was set via a typecast.
4941 If so, then we can also infer a nonzero value range
4942 for the operand of the NOP_EXPR. */
4943 if (comp_code == NE_EXPR && integer_zerop (value))
4946 gimple def_stmt = SSA_NAME_DEF_STMT (t);
4948 while (is_gimple_assign (def_stmt)
4949 && gimple_assign_rhs_code (def_stmt) == NOP_EXPR
4951 (gimple_assign_rhs1 (def_stmt)) == SSA_NAME
4953 (TREE_TYPE (gimple_assign_rhs1 (def_stmt))))
4955 t = gimple_assign_rhs1 (def_stmt);
4956 def_stmt = SSA_NAME_DEF_STMT (t);
4958 /* Note we want to register the assert for the
4959 operand of the NOP_EXPR after SI, not after the
4961 if (! has_single_use (t))
4963 register_new_assert_for (t, t, comp_code, value,
4970 /* If OP is used only once, namely in this STMT, don't
4971 bother creating an ASSERT_EXPR for it. Such an
4972 ASSERT_EXPR would do nothing but increase compile time. */
4973 if (!has_single_use (op))
4975 register_new_assert_for (op, op, comp_code, value,
4983 /* Traverse all PHI nodes in BB marking used operands. */
4984 for (si = gsi_start_phis (bb); !gsi_end_p(si); gsi_next (&si))
4986 use_operand_p arg_p;
4988 phi = gsi_stmt (si);
4990 FOR_EACH_PHI_ARG (arg_p, phi, i, SSA_OP_USE)
4992 tree arg = USE_FROM_PTR (arg_p);
4993 if (TREE_CODE (arg) == SSA_NAME)
4994 SET_BIT (live, SSA_NAME_VERSION (arg));
5001 /* Do an RPO walk over the function computing SSA name liveness
5002 on-the-fly and deciding on assert expressions to insert.
5003 Returns true if there are assert expressions to be inserted. */
5006 find_assert_locations (void)
5008 int *rpo = XCNEWVEC (int, last_basic_block + NUM_FIXED_BLOCKS);
5009 int *bb_rpo = XCNEWVEC (int, last_basic_block + NUM_FIXED_BLOCKS);
5010 int *last_rpo = XCNEWVEC (int, last_basic_block + NUM_FIXED_BLOCKS);
5014 live = XCNEWVEC (sbitmap, last_basic_block + NUM_FIXED_BLOCKS);
5015 rpo_cnt = pre_and_rev_post_order_compute (NULL, rpo, false);
5016 for (i = 0; i < rpo_cnt; ++i)
5019 need_asserts = false;
5020 for (i = rpo_cnt-1; i >= 0; --i)
5022 basic_block bb = BASIC_BLOCK (rpo[i]);
5028 live[rpo[i]] = sbitmap_alloc (num_ssa_names);
5029 sbitmap_zero (live[rpo[i]]);
5032 /* Process BB and update the live information with uses in
5034 need_asserts |= find_assert_locations_1 (bb, live[rpo[i]]);
5036 /* Merge liveness into the predecessor blocks and free it. */
5037 if (!sbitmap_empty_p (live[rpo[i]]))
5040 FOR_EACH_EDGE (e, ei, bb->preds)
5042 int pred = e->src->index;
5043 if (e->flags & EDGE_DFS_BACK)
5048 live[pred] = sbitmap_alloc (num_ssa_names);
5049 sbitmap_zero (live[pred]);
5051 sbitmap_a_or_b (live[pred], live[pred], live[rpo[i]]);
5053 if (bb_rpo[pred] < pred_rpo)
5054 pred_rpo = bb_rpo[pred];
5057 /* Record the RPO number of the last visited block that needs
5058 live information from this block. */
5059 last_rpo[rpo[i]] = pred_rpo;
5063 sbitmap_free (live[rpo[i]]);
5064 live[rpo[i]] = NULL;
5067 /* We can free all successors live bitmaps if all their
5068 predecessors have been visited already. */
5069 FOR_EACH_EDGE (e, ei, bb->succs)
5070 if (last_rpo[e->dest->index] == i
5071 && live[e->dest->index])
5073 sbitmap_free (live[e->dest->index]);
5074 live[e->dest->index] = NULL;
5079 XDELETEVEC (bb_rpo);
5080 XDELETEVEC (last_rpo);
5081 for (i = 0; i < last_basic_block + NUM_FIXED_BLOCKS; ++i)
5083 sbitmap_free (live[i]);
5086 return need_asserts;
5089 /* Create an ASSERT_EXPR for NAME and insert it in the location
5090 indicated by LOC. Return true if we made any edge insertions. */
5093 process_assert_insertions_for (tree name, assert_locus_t loc)
5095 /* Build the comparison expression NAME_i COMP_CODE VAL. */
5102 /* If we have X <=> X do not insert an assert expr for that. */
5103 if (loc->expr == loc->val)
5106 cond = build2 (loc->comp_code, boolean_type_node, loc->expr, loc->val);
5107 assert_stmt = build_assert_expr_for (cond, name);
5110 /* We have been asked to insert the assertion on an edge. This
5111 is used only by COND_EXPR and SWITCH_EXPR assertions. */
5112 gcc_checking_assert (gimple_code (gsi_stmt (loc->si)) == GIMPLE_COND
5113 || (gimple_code (gsi_stmt (loc->si))
5116 gsi_insert_on_edge (loc->e, assert_stmt);
5120 /* Otherwise, we can insert right after LOC->SI iff the
5121 statement must not be the last statement in the block. */
5122 stmt = gsi_stmt (loc->si);
5123 if (!stmt_ends_bb_p (stmt))
5125 gsi_insert_after (&loc->si, assert_stmt, GSI_SAME_STMT);
5129 /* If STMT must be the last statement in BB, we can only insert new
5130 assertions on the non-abnormal edge out of BB. Note that since
5131 STMT is not control flow, there may only be one non-abnormal edge
5133 FOR_EACH_EDGE (e, ei, loc->bb->succs)
5134 if (!(e->flags & EDGE_ABNORMAL))
5136 gsi_insert_on_edge (e, assert_stmt);
5144 /* Process all the insertions registered for every name N_i registered
5145 in NEED_ASSERT_FOR. The list of assertions to be inserted are
5146 found in ASSERTS_FOR[i]. */
5149 process_assert_insertions (void)
5153 bool update_edges_p = false;
5154 int num_asserts = 0;
5156 if (dump_file && (dump_flags & TDF_DETAILS))
5157 dump_all_asserts (dump_file);
5159 EXECUTE_IF_SET_IN_BITMAP (need_assert_for, 0, i, bi)
5161 assert_locus_t loc = asserts_for[i];
5166 assert_locus_t next = loc->next;
5167 update_edges_p |= process_assert_insertions_for (ssa_name (i), loc);
5175 gsi_commit_edge_inserts ();
5177 statistics_counter_event (cfun, "Number of ASSERT_EXPR expressions inserted",
5182 /* Traverse the flowgraph looking for conditional jumps to insert range
5183 expressions. These range expressions are meant to provide information
5184 to optimizations that need to reason in terms of value ranges. They
5185 will not be expanded into RTL. For instance, given:
5194 this pass will transform the code into:
5200 x = ASSERT_EXPR <x, x < y>
5205 y = ASSERT_EXPR <y, x <= y>
5209 The idea is that once copy and constant propagation have run, other
5210 optimizations will be able to determine what ranges of values can 'x'
5211 take in different paths of the code, simply by checking the reaching
5212 definition of 'x'. */
5215 insert_range_assertions (void)
5217 need_assert_for = BITMAP_ALLOC (NULL);
5218 asserts_for = XCNEWVEC (assert_locus_t, num_ssa_names);
5220 calculate_dominance_info (CDI_DOMINATORS);
5222 if (find_assert_locations ())
5224 process_assert_insertions ();
5225 update_ssa (TODO_update_ssa_no_phi);
5228 if (dump_file && (dump_flags & TDF_DETAILS))
5230 fprintf (dump_file, "\nSSA form after inserting ASSERT_EXPRs\n");
5231 dump_function_to_file (current_function_decl, dump_file, dump_flags);
5235 BITMAP_FREE (need_assert_for);
5238 /* Checks one ARRAY_REF in REF, located at LOCUS. Ignores flexible arrays
5239 and "struct" hacks. If VRP can determine that the
5240 array subscript is a constant, check if it is outside valid
5241 range. If the array subscript is a RANGE, warn if it is
5242 non-overlapping with valid range.
5243 IGNORE_OFF_BY_ONE is true if the ARRAY_REF is inside a ADDR_EXPR. */
5246 check_array_ref (location_t location, tree ref, bool ignore_off_by_one)
5248 value_range_t* vr = NULL;
5249 tree low_sub, up_sub;
5250 tree low_bound, up_bound, up_bound_p1;
5253 if (TREE_NO_WARNING (ref))
5256 low_sub = up_sub = TREE_OPERAND (ref, 1);
5257 up_bound = array_ref_up_bound (ref);
5259 /* Can not check flexible arrays. */
5261 || TREE_CODE (up_bound) != INTEGER_CST)
5264 /* Accesses to trailing arrays via pointers may access storage
5265 beyond the types array bounds. */
5266 base = get_base_address (ref);
5267 if (base && TREE_CODE (base) == MEM_REF)
5269 tree cref, next = NULL_TREE;
5271 if (TREE_CODE (TREE_OPERAND (ref, 0)) != COMPONENT_REF)
5274 cref = TREE_OPERAND (ref, 0);
5275 if (TREE_CODE (TREE_TYPE (TREE_OPERAND (cref, 0))) == RECORD_TYPE)
5276 for (next = DECL_CHAIN (TREE_OPERAND (cref, 1));
5277 next && TREE_CODE (next) != FIELD_DECL;
5278 next = DECL_CHAIN (next))
5281 /* If this is the last field in a struct type or a field in a
5282 union type do not warn. */
5287 low_bound = array_ref_low_bound (ref);
5288 up_bound_p1 = int_const_binop (PLUS_EXPR, up_bound, integer_one_node);
5290 if (TREE_CODE (low_sub) == SSA_NAME)
5292 vr = get_value_range (low_sub);
5293 if (vr->type == VR_RANGE || vr->type == VR_ANTI_RANGE)
5295 low_sub = vr->type == VR_RANGE ? vr->max : vr->min;
5296 up_sub = vr->type == VR_RANGE ? vr->min : vr->max;
5300 if (vr && vr->type == VR_ANTI_RANGE)
5302 if (TREE_CODE (up_sub) == INTEGER_CST
5303 && tree_int_cst_lt (up_bound, up_sub)
5304 && TREE_CODE (low_sub) == INTEGER_CST
5305 && tree_int_cst_lt (low_sub, low_bound))
5307 warning_at (location, OPT_Warray_bounds,
5308 "array subscript is outside array bounds");
5309 TREE_NO_WARNING (ref) = 1;
5312 else if (TREE_CODE (up_sub) == INTEGER_CST
5313 && (ignore_off_by_one
5314 ? (tree_int_cst_lt (up_bound, up_sub)
5315 && !tree_int_cst_equal (up_bound_p1, up_sub))
5316 : (tree_int_cst_lt (up_bound, up_sub)
5317 || tree_int_cst_equal (up_bound_p1, up_sub))))
5319 warning_at (location, OPT_Warray_bounds,
5320 "array subscript is above array bounds");
5321 TREE_NO_WARNING (ref) = 1;
5323 else if (TREE_CODE (low_sub) == INTEGER_CST
5324 && tree_int_cst_lt (low_sub, low_bound))
5326 warning_at (location, OPT_Warray_bounds,
5327 "array subscript is below array bounds");
5328 TREE_NO_WARNING (ref) = 1;
5332 /* Searches if the expr T, located at LOCATION computes
5333 address of an ARRAY_REF, and call check_array_ref on it. */
5336 search_for_addr_array (tree t, location_t location)
5338 while (TREE_CODE (t) == SSA_NAME)
5340 gimple g = SSA_NAME_DEF_STMT (t);
5342 if (gimple_code (g) != GIMPLE_ASSIGN)
5345 if (get_gimple_rhs_class (gimple_assign_rhs_code (g))
5346 != GIMPLE_SINGLE_RHS)
5349 t = gimple_assign_rhs1 (g);
5353 /* We are only interested in addresses of ARRAY_REF's. */
5354 if (TREE_CODE (t) != ADDR_EXPR)
5357 /* Check each ARRAY_REFs in the reference chain. */
5360 if (TREE_CODE (t) == ARRAY_REF)
5361 check_array_ref (location, t, true /*ignore_off_by_one*/);
5363 t = TREE_OPERAND (t, 0);
5365 while (handled_component_p (t));
5367 if (TREE_CODE (t) == MEM_REF
5368 && TREE_CODE (TREE_OPERAND (t, 0)) == ADDR_EXPR
5369 && !TREE_NO_WARNING (t))
5371 tree tem = TREE_OPERAND (TREE_OPERAND (t, 0), 0);
5372 tree low_bound, up_bound, el_sz;
5374 if (TREE_CODE (TREE_TYPE (tem)) != ARRAY_TYPE
5375 || TREE_CODE (TREE_TYPE (TREE_TYPE (tem))) == ARRAY_TYPE
5376 || !TYPE_DOMAIN (TREE_TYPE (tem)))
5379 low_bound = TYPE_MIN_VALUE (TYPE_DOMAIN (TREE_TYPE (tem)));
5380 up_bound = TYPE_MAX_VALUE (TYPE_DOMAIN (TREE_TYPE (tem)));
5381 el_sz = TYPE_SIZE_UNIT (TREE_TYPE (TREE_TYPE (tem)));
5383 || TREE_CODE (low_bound) != INTEGER_CST
5385 || TREE_CODE (up_bound) != INTEGER_CST
5387 || TREE_CODE (el_sz) != INTEGER_CST)
5390 idx = mem_ref_offset (t);
5391 idx = double_int_sdiv (idx, tree_to_double_int (el_sz), TRUNC_DIV_EXPR);
5392 if (double_int_scmp (idx, double_int_zero) < 0)
5394 warning_at (location, OPT_Warray_bounds,
5395 "array subscript is below array bounds");
5396 TREE_NO_WARNING (t) = 1;
5398 else if (double_int_scmp (idx,
5401 (tree_to_double_int (up_bound),
5403 (tree_to_double_int (low_bound))),
5404 double_int_one)) > 0)
5406 warning_at (location, OPT_Warray_bounds,
5407 "array subscript is above array bounds");
5408 TREE_NO_WARNING (t) = 1;
5413 /* walk_tree() callback that checks if *TP is
5414 an ARRAY_REF inside an ADDR_EXPR (in which an array
5415 subscript one outside the valid range is allowed). Call
5416 check_array_ref for each ARRAY_REF found. The location is
5420 check_array_bounds (tree *tp, int *walk_subtree, void *data)
5423 struct walk_stmt_info *wi = (struct walk_stmt_info *) data;
5424 location_t location;
5426 if (EXPR_HAS_LOCATION (t))
5427 location = EXPR_LOCATION (t);
5430 location_t *locp = (location_t *) wi->info;
5434 *walk_subtree = TRUE;
5436 if (TREE_CODE (t) == ARRAY_REF)
5437 check_array_ref (location, t, false /*ignore_off_by_one*/);
5439 if (TREE_CODE (t) == MEM_REF
5440 || (TREE_CODE (t) == RETURN_EXPR && TREE_OPERAND (t, 0)))
5441 search_for_addr_array (TREE_OPERAND (t, 0), location);
5443 if (TREE_CODE (t) == ADDR_EXPR)
5444 *walk_subtree = FALSE;
5449 /* Walk over all statements of all reachable BBs and call check_array_bounds
5453 check_all_array_refs (void)
5456 gimple_stmt_iterator si;
5462 bool executable = false;
5464 /* Skip blocks that were found to be unreachable. */
5465 FOR_EACH_EDGE (e, ei, bb->preds)
5466 executable |= !!(e->flags & EDGE_EXECUTABLE);
5470 for (si = gsi_start_bb (bb); !gsi_end_p (si); gsi_next (&si))
5472 gimple stmt = gsi_stmt (si);
5473 struct walk_stmt_info wi;
5474 if (!gimple_has_location (stmt))
5477 if (is_gimple_call (stmt))
5480 size_t n = gimple_call_num_args (stmt);
5481 for (i = 0; i < n; i++)
5483 tree arg = gimple_call_arg (stmt, i);
5484 search_for_addr_array (arg, gimple_location (stmt));
5489 memset (&wi, 0, sizeof (wi));
5490 wi.info = CONST_CAST (void *, (const void *)
5491 gimple_location_ptr (stmt));
5493 walk_gimple_op (gsi_stmt (si),
5501 /* Convert range assertion expressions into the implied copies and
5502 copy propagate away the copies. Doing the trivial copy propagation
5503 here avoids the need to run the full copy propagation pass after
5506 FIXME, this will eventually lead to copy propagation removing the
5507 names that had useful range information attached to them. For
5508 instance, if we had the assertion N_i = ASSERT_EXPR <N_j, N_j > 3>,
5509 then N_i will have the range [3, +INF].
5511 However, by converting the assertion into the implied copy
5512 operation N_i = N_j, we will then copy-propagate N_j into the uses
5513 of N_i and lose the range information. We may want to hold on to
5514 ASSERT_EXPRs a little while longer as the ranges could be used in
5515 things like jump threading.
5517 The problem with keeping ASSERT_EXPRs around is that passes after
5518 VRP need to handle them appropriately.
5520 Another approach would be to make the range information a first
5521 class property of the SSA_NAME so that it can be queried from
5522 any pass. This is made somewhat more complex by the need for
5523 multiple ranges to be associated with one SSA_NAME. */
5526 remove_range_assertions (void)
5529 gimple_stmt_iterator si;
5531 /* Note that the BSI iterator bump happens at the bottom of the
5532 loop and no bump is necessary if we're removing the statement
5533 referenced by the current BSI. */
5535 for (si = gsi_start_bb (bb); !gsi_end_p (si);)
5537 gimple stmt = gsi_stmt (si);
5540 if (is_gimple_assign (stmt)
5541 && gimple_assign_rhs_code (stmt) == ASSERT_EXPR)
5543 tree rhs = gimple_assign_rhs1 (stmt);
5545 tree cond = fold (ASSERT_EXPR_COND (rhs));
5546 use_operand_p use_p;
5547 imm_use_iterator iter;
5549 gcc_assert (cond != boolean_false_node);
5551 /* Propagate the RHS into every use of the LHS. */
5552 var = ASSERT_EXPR_VAR (rhs);
5553 FOR_EACH_IMM_USE_STMT (use_stmt, iter,
5554 gimple_assign_lhs (stmt))
5555 FOR_EACH_IMM_USE_ON_STMT (use_p, iter)
5557 SET_USE (use_p, var);
5558 gcc_assert (TREE_CODE (var) == SSA_NAME);
5561 /* And finally, remove the copy, it is not needed. */
5562 gsi_remove (&si, true);
5563 release_defs (stmt);
5571 /* Return true if STMT is interesting for VRP. */
5574 stmt_interesting_for_vrp (gimple stmt)
5576 if (gimple_code (stmt) == GIMPLE_PHI
5577 && is_gimple_reg (gimple_phi_result (stmt))
5578 && (INTEGRAL_TYPE_P (TREE_TYPE (gimple_phi_result (stmt)))
5579 || POINTER_TYPE_P (TREE_TYPE (gimple_phi_result (stmt)))))
5581 else if (is_gimple_assign (stmt) || is_gimple_call (stmt))
5583 tree lhs = gimple_get_lhs (stmt);
5585 /* In general, assignments with virtual operands are not useful
5586 for deriving ranges, with the obvious exception of calls to
5587 builtin functions. */
5588 if (lhs && TREE_CODE (lhs) == SSA_NAME
5589 && (INTEGRAL_TYPE_P (TREE_TYPE (lhs))
5590 || POINTER_TYPE_P (TREE_TYPE (lhs)))
5591 && ((is_gimple_call (stmt)
5592 && gimple_call_fndecl (stmt) != NULL_TREE
5593 && DECL_IS_BUILTIN (gimple_call_fndecl (stmt)))
5594 || !gimple_vuse (stmt)))
5597 else if (gimple_code (stmt) == GIMPLE_COND
5598 || gimple_code (stmt) == GIMPLE_SWITCH)
5605 /* Initialize local data structures for VRP. */
5608 vrp_initialize (void)
5612 values_propagated = false;
5613 num_vr_values = num_ssa_names;
5614 vr_value = XCNEWVEC (value_range_t *, num_vr_values);
5615 vr_phi_edge_counts = XCNEWVEC (int, num_ssa_names);
5619 gimple_stmt_iterator si;
5621 for (si = gsi_start_phis (bb); !gsi_end_p (si); gsi_next (&si))
5623 gimple phi = gsi_stmt (si);
5624 if (!stmt_interesting_for_vrp (phi))
5626 tree lhs = PHI_RESULT (phi);
5627 set_value_range_to_varying (get_value_range (lhs));
5628 prop_set_simulate_again (phi, false);
5631 prop_set_simulate_again (phi, true);
5634 for (si = gsi_start_bb (bb); !gsi_end_p (si); gsi_next (&si))
5636 gimple stmt = gsi_stmt (si);
5638 /* If the statement is a control insn, then we do not
5639 want to avoid simulating the statement once. Failure
5640 to do so means that those edges will never get added. */
5641 if (stmt_ends_bb_p (stmt))
5642 prop_set_simulate_again (stmt, true);
5643 else if (!stmt_interesting_for_vrp (stmt))
5647 FOR_EACH_SSA_TREE_OPERAND (def, stmt, i, SSA_OP_DEF)
5648 set_value_range_to_varying (get_value_range (def));
5649 prop_set_simulate_again (stmt, false);
5652 prop_set_simulate_again (stmt, true);
5657 /* Return the singleton value-range for NAME or NAME. */
5660 vrp_valueize (tree name)
5662 if (TREE_CODE (name) == SSA_NAME)
5664 value_range_t *vr = get_value_range (name);
5665 if (vr->type == VR_RANGE
5666 && (vr->min == vr->max
5667 || operand_equal_p (vr->min, vr->max, 0)))
5673 /* Visit assignment STMT. If it produces an interesting range, record
5674 the SSA name in *OUTPUT_P. */
5676 static enum ssa_prop_result
5677 vrp_visit_assignment_or_call (gimple stmt, tree *output_p)
5681 enum gimple_code code = gimple_code (stmt);
5682 lhs = gimple_get_lhs (stmt);
5684 /* We only keep track of ranges in integral and pointer types. */
5685 if (TREE_CODE (lhs) == SSA_NAME
5686 && ((INTEGRAL_TYPE_P (TREE_TYPE (lhs))
5687 /* It is valid to have NULL MIN/MAX values on a type. See
5688 build_range_type. */
5689 && TYPE_MIN_VALUE (TREE_TYPE (lhs))
5690 && TYPE_MAX_VALUE (TREE_TYPE (lhs)))
5691 || POINTER_TYPE_P (TREE_TYPE (lhs))))
5693 value_range_t new_vr = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
5695 /* Try folding the statement to a constant first. */
5696 tree tem = gimple_fold_stmt_to_constant (stmt, vrp_valueize);
5697 if (tem && !is_overflow_infinity (tem))
5698 set_value_range (&new_vr, VR_RANGE, tem, tem, NULL);
5699 /* Then dispatch to value-range extracting functions. */
5700 else if (code == GIMPLE_CALL)
5701 extract_range_basic (&new_vr, stmt);
5703 extract_range_from_assignment (&new_vr, stmt);
5705 if (update_value_range (lhs, &new_vr))
5709 if (dump_file && (dump_flags & TDF_DETAILS))
5711 fprintf (dump_file, "Found new range for ");
5712 print_generic_expr (dump_file, lhs, 0);
5713 fprintf (dump_file, ": ");
5714 dump_value_range (dump_file, &new_vr);
5715 fprintf (dump_file, "\n\n");
5718 if (new_vr.type == VR_VARYING)
5719 return SSA_PROP_VARYING;
5721 return SSA_PROP_INTERESTING;
5724 return SSA_PROP_NOT_INTERESTING;
5727 /* Every other statement produces no useful ranges. */
5728 FOR_EACH_SSA_TREE_OPERAND (def, stmt, iter, SSA_OP_DEF)
5729 set_value_range_to_varying (get_value_range (def));
5731 return SSA_PROP_VARYING;
5734 /* Helper that gets the value range of the SSA_NAME with version I
5735 or a symbolic range containing the SSA_NAME only if the value range
5736 is varying or undefined. */
5738 static inline value_range_t
5739 get_vr_for_comparison (int i)
5741 value_range_t vr = *get_value_range (ssa_name (i));
5743 /* If name N_i does not have a valid range, use N_i as its own
5744 range. This allows us to compare against names that may
5745 have N_i in their ranges. */
5746 if (vr.type == VR_VARYING || vr.type == VR_UNDEFINED)
5749 vr.min = ssa_name (i);
5750 vr.max = ssa_name (i);
5756 /* Compare all the value ranges for names equivalent to VAR with VAL
5757 using comparison code COMP. Return the same value returned by
5758 compare_range_with_value, including the setting of
5759 *STRICT_OVERFLOW_P. */
5762 compare_name_with_value (enum tree_code comp, tree var, tree val,
5763 bool *strict_overflow_p)
5769 int used_strict_overflow;
5771 value_range_t equiv_vr;
5773 /* Get the set of equivalences for VAR. */
5774 e = get_value_range (var)->equiv;
5776 /* Start at -1. Set it to 0 if we do a comparison without relying
5777 on overflow, or 1 if all comparisons rely on overflow. */
5778 used_strict_overflow = -1;
5780 /* Compare vars' value range with val. */
5781 equiv_vr = get_vr_for_comparison (SSA_NAME_VERSION (var));
5783 retval = compare_range_with_value (comp, &equiv_vr, val, &sop);
5785 used_strict_overflow = sop ? 1 : 0;
5787 /* If the equiv set is empty we have done all work we need to do. */
5791 && used_strict_overflow > 0)
5792 *strict_overflow_p = true;
5796 EXECUTE_IF_SET_IN_BITMAP (e, 0, i, bi)
5798 equiv_vr = get_vr_for_comparison (i);
5800 t = compare_range_with_value (comp, &equiv_vr, val, &sop);
5803 /* If we get different answers from different members
5804 of the equivalence set this check must be in a dead
5805 code region. Folding it to a trap representation
5806 would be correct here. For now just return don't-know. */
5816 used_strict_overflow = 0;
5817 else if (used_strict_overflow < 0)
5818 used_strict_overflow = 1;
5823 && used_strict_overflow > 0)
5824 *strict_overflow_p = true;
5830 /* Given a comparison code COMP and names N1 and N2, compare all the
5831 ranges equivalent to N1 against all the ranges equivalent to N2
5832 to determine the value of N1 COMP N2. Return the same value
5833 returned by compare_ranges. Set *STRICT_OVERFLOW_P to indicate
5834 whether we relied on an overflow infinity in the comparison. */
5838 compare_names (enum tree_code comp, tree n1, tree n2,
5839 bool *strict_overflow_p)
5843 bitmap_iterator bi1, bi2;
5845 int used_strict_overflow;
5846 static bitmap_obstack *s_obstack = NULL;
5847 static bitmap s_e1 = NULL, s_e2 = NULL;
5849 /* Compare the ranges of every name equivalent to N1 against the
5850 ranges of every name equivalent to N2. */
5851 e1 = get_value_range (n1)->equiv;
5852 e2 = get_value_range (n2)->equiv;
5854 /* Use the fake bitmaps if e1 or e2 are not available. */
5855 if (s_obstack == NULL)
5857 s_obstack = XNEW (bitmap_obstack);
5858 bitmap_obstack_initialize (s_obstack);
5859 s_e1 = BITMAP_ALLOC (s_obstack);
5860 s_e2 = BITMAP_ALLOC (s_obstack);
5867 /* Add N1 and N2 to their own set of equivalences to avoid
5868 duplicating the body of the loop just to check N1 and N2
5870 bitmap_set_bit (e1, SSA_NAME_VERSION (n1));
5871 bitmap_set_bit (e2, SSA_NAME_VERSION (n2));
5873 /* If the equivalence sets have a common intersection, then the two
5874 names can be compared without checking their ranges. */
5875 if (bitmap_intersect_p (e1, e2))
5877 bitmap_clear_bit (e1, SSA_NAME_VERSION (n1));
5878 bitmap_clear_bit (e2, SSA_NAME_VERSION (n2));
5880 return (comp == EQ_EXPR || comp == GE_EXPR || comp == LE_EXPR)
5882 : boolean_false_node;
5885 /* Start at -1. Set it to 0 if we do a comparison without relying
5886 on overflow, or 1 if all comparisons rely on overflow. */
5887 used_strict_overflow = -1;
5889 /* Otherwise, compare all the equivalent ranges. First, add N1 and
5890 N2 to their own set of equivalences to avoid duplicating the body
5891 of the loop just to check N1 and N2 ranges. */
5892 EXECUTE_IF_SET_IN_BITMAP (e1, 0, i1, bi1)
5894 value_range_t vr1 = get_vr_for_comparison (i1);
5896 t = retval = NULL_TREE;
5897 EXECUTE_IF_SET_IN_BITMAP (e2, 0, i2, bi2)
5901 value_range_t vr2 = get_vr_for_comparison (i2);
5903 t = compare_ranges (comp, &vr1, &vr2, &sop);
5906 /* If we get different answers from different members
5907 of the equivalence set this check must be in a dead
5908 code region. Folding it to a trap representation
5909 would be correct here. For now just return don't-know. */
5913 bitmap_clear_bit (e1, SSA_NAME_VERSION (n1));
5914 bitmap_clear_bit (e2, SSA_NAME_VERSION (n2));
5920 used_strict_overflow = 0;
5921 else if (used_strict_overflow < 0)
5922 used_strict_overflow = 1;
5928 bitmap_clear_bit (e1, SSA_NAME_VERSION (n1));
5929 bitmap_clear_bit (e2, SSA_NAME_VERSION (n2));
5930 if (used_strict_overflow > 0)
5931 *strict_overflow_p = true;
5936 /* None of the equivalent ranges are useful in computing this
5938 bitmap_clear_bit (e1, SSA_NAME_VERSION (n1));
5939 bitmap_clear_bit (e2, SSA_NAME_VERSION (n2));
5943 /* Helper function for vrp_evaluate_conditional_warnv. */
5946 vrp_evaluate_conditional_warnv_with_ops_using_ranges (enum tree_code code,
5948 bool * strict_overflow_p)
5950 value_range_t *vr0, *vr1;
5952 vr0 = (TREE_CODE (op0) == SSA_NAME) ? get_value_range (op0) : NULL;
5953 vr1 = (TREE_CODE (op1) == SSA_NAME) ? get_value_range (op1) : NULL;
5956 return compare_ranges (code, vr0, vr1, strict_overflow_p);
5957 else if (vr0 && vr1 == NULL)
5958 return compare_range_with_value (code, vr0, op1, strict_overflow_p);
5959 else if (vr0 == NULL && vr1)
5960 return (compare_range_with_value
5961 (swap_tree_comparison (code), vr1, op0, strict_overflow_p));
5965 /* Helper function for vrp_evaluate_conditional_warnv. */
5968 vrp_evaluate_conditional_warnv_with_ops (enum tree_code code, tree op0,
5969 tree op1, bool use_equiv_p,
5970 bool *strict_overflow_p, bool *only_ranges)
5974 *only_ranges = true;
5976 /* We only deal with integral and pointer types. */
5977 if (!INTEGRAL_TYPE_P (TREE_TYPE (op0))
5978 && !POINTER_TYPE_P (TREE_TYPE (op0)))
5984 && (ret = vrp_evaluate_conditional_warnv_with_ops_using_ranges
5985 (code, op0, op1, strict_overflow_p)))
5987 *only_ranges = false;
5988 if (TREE_CODE (op0) == SSA_NAME && TREE_CODE (op1) == SSA_NAME)
5989 return compare_names (code, op0, op1, strict_overflow_p);
5990 else if (TREE_CODE (op0) == SSA_NAME)
5991 return compare_name_with_value (code, op0, op1, strict_overflow_p);
5992 else if (TREE_CODE (op1) == SSA_NAME)
5993 return (compare_name_with_value
5994 (swap_tree_comparison (code), op1, op0, strict_overflow_p));
5997 return vrp_evaluate_conditional_warnv_with_ops_using_ranges (code, op0, op1,
6002 /* Given (CODE OP0 OP1) within STMT, try to simplify it based on value range
6003 information. Return NULL if the conditional can not be evaluated.
6004 The ranges of all the names equivalent with the operands in COND
6005 will be used when trying to compute the value. If the result is
6006 based on undefined signed overflow, issue a warning if
6010 vrp_evaluate_conditional (enum tree_code code, tree op0, tree op1, gimple stmt)
6016 /* Some passes and foldings leak constants with overflow flag set
6017 into the IL. Avoid doing wrong things with these and bail out. */
6018 if ((TREE_CODE (op0) == INTEGER_CST
6019 && TREE_OVERFLOW (op0))
6020 || (TREE_CODE (op1) == INTEGER_CST
6021 && TREE_OVERFLOW (op1)))
6025 ret = vrp_evaluate_conditional_warnv_with_ops (code, op0, op1, true, &sop,
6030 enum warn_strict_overflow_code wc;
6031 const char* warnmsg;
6033 if (is_gimple_min_invariant (ret))
6035 wc = WARN_STRICT_OVERFLOW_CONDITIONAL;
6036 warnmsg = G_("assuming signed overflow does not occur when "
6037 "simplifying conditional to constant");
6041 wc = WARN_STRICT_OVERFLOW_COMPARISON;
6042 warnmsg = G_("assuming signed overflow does not occur when "
6043 "simplifying conditional");
6046 if (issue_strict_overflow_warning (wc))
6048 location_t location;
6050 if (!gimple_has_location (stmt))
6051 location = input_location;
6053 location = gimple_location (stmt);
6054 warning_at (location, OPT_Wstrict_overflow, "%s", warnmsg);
6058 if (warn_type_limits
6059 && ret && only_ranges
6060 && TREE_CODE_CLASS (code) == tcc_comparison
6061 && TREE_CODE (op0) == SSA_NAME)
6063 /* If the comparison is being folded and the operand on the LHS
6064 is being compared against a constant value that is outside of
6065 the natural range of OP0's type, then the predicate will
6066 always fold regardless of the value of OP0. If -Wtype-limits
6067 was specified, emit a warning. */
6068 tree type = TREE_TYPE (op0);
6069 value_range_t *vr0 = get_value_range (op0);
6071 if (vr0->type != VR_VARYING
6072 && INTEGRAL_TYPE_P (type)
6073 && vrp_val_is_min (vr0->min)
6074 && vrp_val_is_max (vr0->max)
6075 && is_gimple_min_invariant (op1))
6077 location_t location;
6079 if (!gimple_has_location (stmt))
6080 location = input_location;
6082 location = gimple_location (stmt);
6084 warning_at (location, OPT_Wtype_limits,
6086 ? G_("comparison always false "
6087 "due to limited range of data type")
6088 : G_("comparison always true "
6089 "due to limited range of data type"));
6097 /* Visit conditional statement STMT. If we can determine which edge
6098 will be taken out of STMT's basic block, record it in
6099 *TAKEN_EDGE_P and return SSA_PROP_INTERESTING. Otherwise, return
6100 SSA_PROP_VARYING. */
6102 static enum ssa_prop_result
6103 vrp_visit_cond_stmt (gimple stmt, edge *taken_edge_p)
6108 *taken_edge_p = NULL;
6110 if (dump_file && (dump_flags & TDF_DETAILS))
6115 fprintf (dump_file, "\nVisiting conditional with predicate: ");
6116 print_gimple_stmt (dump_file, stmt, 0, 0);
6117 fprintf (dump_file, "\nWith known ranges\n");
6119 FOR_EACH_SSA_TREE_OPERAND (use, stmt, i, SSA_OP_USE)
6121 fprintf (dump_file, "\t");
6122 print_generic_expr (dump_file, use, 0);
6123 fprintf (dump_file, ": ");
6124 dump_value_range (dump_file, vr_value[SSA_NAME_VERSION (use)]);
6127 fprintf (dump_file, "\n");
6130 /* Compute the value of the predicate COND by checking the known
6131 ranges of each of its operands.
6133 Note that we cannot evaluate all the equivalent ranges here
6134 because those ranges may not yet be final and with the current
6135 propagation strategy, we cannot determine when the value ranges
6136 of the names in the equivalence set have changed.
6138 For instance, given the following code fragment
6142 i_14 = ASSERT_EXPR <i_5, i_5 != 0>
6146 Assume that on the first visit to i_14, i_5 has the temporary
6147 range [8, 8] because the second argument to the PHI function is
6148 not yet executable. We derive the range ~[0, 0] for i_14 and the
6149 equivalence set { i_5 }. So, when we visit 'if (i_14 == 1)' for
6150 the first time, since i_14 is equivalent to the range [8, 8], we
6151 determine that the predicate is always false.
6153 On the next round of propagation, i_13 is determined to be
6154 VARYING, which causes i_5 to drop down to VARYING. So, another
6155 visit to i_14 is scheduled. In this second visit, we compute the
6156 exact same range and equivalence set for i_14, namely ~[0, 0] and
6157 { i_5 }. But we did not have the previous range for i_5
6158 registered, so vrp_visit_assignment thinks that the range for
6159 i_14 has not changed. Therefore, the predicate 'if (i_14 == 1)'
6160 is not visited again, which stops propagation from visiting
6161 statements in the THEN clause of that if().
6163 To properly fix this we would need to keep the previous range
6164 value for the names in the equivalence set. This way we would've
6165 discovered that from one visit to the other i_5 changed from
6166 range [8, 8] to VR_VARYING.
6168 However, fixing this apparent limitation may not be worth the
6169 additional checking. Testing on several code bases (GCC, DLV,
6170 MICO, TRAMP3D and SPEC2000) showed that doing this results in
6171 4 more predicates folded in SPEC. */
6174 val = vrp_evaluate_conditional_warnv_with_ops (gimple_cond_code (stmt),
6175 gimple_cond_lhs (stmt),
6176 gimple_cond_rhs (stmt),
6181 *taken_edge_p = find_taken_edge (gimple_bb (stmt), val);
6184 if (dump_file && (dump_flags & TDF_DETAILS))
6186 "\nIgnoring predicate evaluation because "
6187 "it assumes that signed overflow is undefined");
6192 if (dump_file && (dump_flags & TDF_DETAILS))
6194 fprintf (dump_file, "\nPredicate evaluates to: ");
6195 if (val == NULL_TREE)
6196 fprintf (dump_file, "DON'T KNOW\n");
6198 print_generic_stmt (dump_file, val, 0);
6201 return (*taken_edge_p) ? SSA_PROP_INTERESTING : SSA_PROP_VARYING;
6204 /* Searches the case label vector VEC for the index *IDX of the CASE_LABEL
6205 that includes the value VAL. The search is restricted to the range
6206 [START_IDX, n - 1] where n is the size of VEC.
6208 If there is a CASE_LABEL for VAL, its index is placed in IDX and true is
6211 If there is no CASE_LABEL for VAL and there is one that is larger than VAL,
6212 it is placed in IDX and false is returned.
6214 If VAL is larger than any CASE_LABEL, n is placed on IDX and false is
6218 find_case_label_index (gimple stmt, size_t start_idx, tree val, size_t *idx)
6220 size_t n = gimple_switch_num_labels (stmt);
6223 /* Find case label for minimum of the value range or the next one.
6224 At each iteration we are searching in [low, high - 1]. */
6226 for (low = start_idx, high = n; high != low; )
6230 /* Note that i != high, so we never ask for n. */
6231 size_t i = (high + low) / 2;
6232 t = gimple_switch_label (stmt, i);
6234 /* Cache the result of comparing CASE_LOW and val. */
6235 cmp = tree_int_cst_compare (CASE_LOW (t), val);
6239 /* Ranges cannot be empty. */
6248 if (CASE_HIGH (t) != NULL
6249 && tree_int_cst_compare (CASE_HIGH (t), val) >= 0)
6261 /* Searches the case label vector VEC for the range of CASE_LABELs that is used
6262 for values between MIN and MAX. The first index is placed in MIN_IDX. The
6263 last index is placed in MAX_IDX. If the range of CASE_LABELs is empty
6264 then MAX_IDX < MIN_IDX.
6265 Returns true if the default label is not needed. */
6268 find_case_label_range (gimple stmt, tree min, tree max, size_t *min_idx,
6272 bool min_take_default = !find_case_label_index (stmt, 1, min, &i);
6273 bool max_take_default = !find_case_label_index (stmt, i, max, &j);
6277 && max_take_default)
6279 /* Only the default case label reached.
6280 Return an empty range. */
6287 bool take_default = min_take_default || max_take_default;
6291 if (max_take_default)
6294 /* If the case label range is continuous, we do not need
6295 the default case label. Verify that. */
6296 high = CASE_LOW (gimple_switch_label (stmt, i));
6297 if (CASE_HIGH (gimple_switch_label (stmt, i)))
6298 high = CASE_HIGH (gimple_switch_label (stmt, i));
6299 for (k = i + 1; k <= j; ++k)
6301 low = CASE_LOW (gimple_switch_label (stmt, k));
6302 if (!integer_onep (int_const_binop (MINUS_EXPR, low, high)))
6304 take_default = true;
6308 if (CASE_HIGH (gimple_switch_label (stmt, k)))
6309 high = CASE_HIGH (gimple_switch_label (stmt, k));
6314 return !take_default;
6318 /* Visit switch statement STMT. If we can determine which edge
6319 will be taken out of STMT's basic block, record it in
6320 *TAKEN_EDGE_P and return SSA_PROP_INTERESTING. Otherwise, return
6321 SSA_PROP_VARYING. */
6323 static enum ssa_prop_result
6324 vrp_visit_switch_stmt (gimple stmt, edge *taken_edge_p)
6328 size_t i = 0, j = 0;
6331 *taken_edge_p = NULL;
6332 op = gimple_switch_index (stmt);
6333 if (TREE_CODE (op) != SSA_NAME)
6334 return SSA_PROP_VARYING;
6336 vr = get_value_range (op);
6337 if (dump_file && (dump_flags & TDF_DETAILS))
6339 fprintf (dump_file, "\nVisiting switch expression with operand ");
6340 print_generic_expr (dump_file, op, 0);
6341 fprintf (dump_file, " with known range ");
6342 dump_value_range (dump_file, vr);
6343 fprintf (dump_file, "\n");
6346 if (vr->type != VR_RANGE
6347 || symbolic_range_p (vr))
6348 return SSA_PROP_VARYING;
6350 /* Find the single edge that is taken from the switch expression. */
6351 take_default = !find_case_label_range (stmt, vr->min, vr->max, &i, &j);
6353 /* Check if the range spans no CASE_LABEL. If so, we only reach the default
6357 gcc_assert (take_default);
6358 val = gimple_switch_default_label (stmt);
6362 /* Check if labels with index i to j and maybe the default label
6363 are all reaching the same label. */
6365 val = gimple_switch_label (stmt, i);
6367 && CASE_LABEL (gimple_switch_default_label (stmt))
6368 != CASE_LABEL (val))
6370 if (dump_file && (dump_flags & TDF_DETAILS))
6371 fprintf (dump_file, " not a single destination for this "
6373 return SSA_PROP_VARYING;
6375 for (++i; i <= j; ++i)
6377 if (CASE_LABEL (gimple_switch_label (stmt, i)) != CASE_LABEL (val))
6379 if (dump_file && (dump_flags & TDF_DETAILS))
6380 fprintf (dump_file, " not a single destination for this "
6382 return SSA_PROP_VARYING;
6387 *taken_edge_p = find_edge (gimple_bb (stmt),
6388 label_to_block (CASE_LABEL (val)));
6390 if (dump_file && (dump_flags & TDF_DETAILS))
6392 fprintf (dump_file, " will take edge to ");
6393 print_generic_stmt (dump_file, CASE_LABEL (val), 0);
6396 return SSA_PROP_INTERESTING;
6400 /* Evaluate statement STMT. If the statement produces a useful range,
6401 return SSA_PROP_INTERESTING and record the SSA name with the
6402 interesting range into *OUTPUT_P.
6404 If STMT is a conditional branch and we can determine its truth
6405 value, the taken edge is recorded in *TAKEN_EDGE_P.
6407 If STMT produces a varying value, return SSA_PROP_VARYING. */
6409 static enum ssa_prop_result
6410 vrp_visit_stmt (gimple stmt, edge *taken_edge_p, tree *output_p)
6415 if (dump_file && (dump_flags & TDF_DETAILS))
6417 fprintf (dump_file, "\nVisiting statement:\n");
6418 print_gimple_stmt (dump_file, stmt, 0, dump_flags);
6419 fprintf (dump_file, "\n");
6422 if (!stmt_interesting_for_vrp (stmt))
6423 gcc_assert (stmt_ends_bb_p (stmt));
6424 else if (is_gimple_assign (stmt) || is_gimple_call (stmt))
6426 /* In general, assignments with virtual operands are not useful
6427 for deriving ranges, with the obvious exception of calls to
6428 builtin functions. */
6429 if ((is_gimple_call (stmt)
6430 && gimple_call_fndecl (stmt) != NULL_TREE
6431 && DECL_IS_BUILTIN (gimple_call_fndecl (stmt)))
6432 || !gimple_vuse (stmt))
6433 return vrp_visit_assignment_or_call (stmt, output_p);
6435 else if (gimple_code (stmt) == GIMPLE_COND)
6436 return vrp_visit_cond_stmt (stmt, taken_edge_p);
6437 else if (gimple_code (stmt) == GIMPLE_SWITCH)
6438 return vrp_visit_switch_stmt (stmt, taken_edge_p);
6440 /* All other statements produce nothing of interest for VRP, so mark
6441 their outputs varying and prevent further simulation. */
6442 FOR_EACH_SSA_TREE_OPERAND (def, stmt, iter, SSA_OP_DEF)
6443 set_value_range_to_varying (get_value_range (def));
6445 return SSA_PROP_VARYING;
6449 /* Meet operation for value ranges. Given two value ranges VR0 and
6450 VR1, store in VR0 a range that contains both VR0 and VR1. This
6451 may not be the smallest possible such range. */
6454 vrp_meet (value_range_t *vr0, value_range_t *vr1)
6456 if (vr0->type == VR_UNDEFINED)
6458 copy_value_range (vr0, vr1);
6462 if (vr1->type == VR_UNDEFINED)
6464 /* Nothing to do. VR0 already has the resulting range. */
6468 if (vr0->type == VR_VARYING)
6470 /* Nothing to do. VR0 already has the resulting range. */
6474 if (vr1->type == VR_VARYING)
6476 set_value_range_to_varying (vr0);
6480 if (vr0->type == VR_RANGE && vr1->type == VR_RANGE)
6485 /* Compute the convex hull of the ranges. The lower limit of
6486 the new range is the minimum of the two ranges. If they
6487 cannot be compared, then give up. */
6488 cmp = compare_values (vr0->min, vr1->min);
6489 if (cmp == 0 || cmp == 1)
6496 /* Similarly, the upper limit of the new range is the maximum
6497 of the two ranges. If they cannot be compared, then
6499 cmp = compare_values (vr0->max, vr1->max);
6500 if (cmp == 0 || cmp == -1)
6507 /* Check for useless ranges. */
6508 if (INTEGRAL_TYPE_P (TREE_TYPE (min))
6509 && ((vrp_val_is_min (min) || is_overflow_infinity (min))
6510 && (vrp_val_is_max (max) || is_overflow_infinity (max))))
6513 /* The resulting set of equivalences is the intersection of
6515 if (vr0->equiv && vr1->equiv && vr0->equiv != vr1->equiv)
6516 bitmap_and_into (vr0->equiv, vr1->equiv);
6517 else if (vr0->equiv && !vr1->equiv)
6518 bitmap_clear (vr0->equiv);
6520 set_value_range (vr0, vr0->type, min, max, vr0->equiv);
6522 else if (vr0->type == VR_ANTI_RANGE && vr1->type == VR_ANTI_RANGE)
6524 /* Two anti-ranges meet only if their complements intersect.
6525 Only handle the case of identical ranges. */
6526 if (compare_values (vr0->min, vr1->min) == 0
6527 && compare_values (vr0->max, vr1->max) == 0
6528 && compare_values (vr0->min, vr0->max) == 0)
6530 /* The resulting set of equivalences is the intersection of
6532 if (vr0->equiv && vr1->equiv && vr0->equiv != vr1->equiv)
6533 bitmap_and_into (vr0->equiv, vr1->equiv);
6534 else if (vr0->equiv && !vr1->equiv)
6535 bitmap_clear (vr0->equiv);
6540 else if (vr0->type == VR_ANTI_RANGE || vr1->type == VR_ANTI_RANGE)
6542 /* For a numeric range [VAL1, VAL2] and an anti-range ~[VAL3, VAL4],
6543 only handle the case where the ranges have an empty intersection.
6544 The result of the meet operation is the anti-range. */
6545 if (!symbolic_range_p (vr0)
6546 && !symbolic_range_p (vr1)
6547 && !value_ranges_intersect_p (vr0, vr1))
6549 /* Copy most of VR1 into VR0. Don't copy VR1's equivalence
6550 set. We need to compute the intersection of the two
6551 equivalence sets. */
6552 if (vr1->type == VR_ANTI_RANGE)
6553 set_value_range (vr0, vr1->type, vr1->min, vr1->max, vr0->equiv);
6555 /* The resulting set of equivalences is the intersection of
6557 if (vr0->equiv && vr1->equiv && vr0->equiv != vr1->equiv)
6558 bitmap_and_into (vr0->equiv, vr1->equiv);
6559 else if (vr0->equiv && !vr1->equiv)
6560 bitmap_clear (vr0->equiv);
6571 /* Failed to find an efficient meet. Before giving up and setting
6572 the result to VARYING, see if we can at least derive a useful
6573 anti-range. FIXME, all this nonsense about distinguishing
6574 anti-ranges from ranges is necessary because of the odd
6575 semantics of range_includes_zero_p and friends. */
6576 if (!symbolic_range_p (vr0)
6577 && ((vr0->type == VR_RANGE && !range_includes_zero_p (vr0))
6578 || (vr0->type == VR_ANTI_RANGE && range_includes_zero_p (vr0)))
6579 && !symbolic_range_p (vr1)
6580 && ((vr1->type == VR_RANGE && !range_includes_zero_p (vr1))
6581 || (vr1->type == VR_ANTI_RANGE && range_includes_zero_p (vr1))))
6583 set_value_range_to_nonnull (vr0, TREE_TYPE (vr0->min));
6585 /* Since this meet operation did not result from the meeting of
6586 two equivalent names, VR0 cannot have any equivalences. */
6588 bitmap_clear (vr0->equiv);
6591 set_value_range_to_varying (vr0);
6595 /* Visit all arguments for PHI node PHI that flow through executable
6596 edges. If a valid value range can be derived from all the incoming
6597 value ranges, set a new range for the LHS of PHI. */
6599 static enum ssa_prop_result
6600 vrp_visit_phi_node (gimple phi)
6603 tree lhs = PHI_RESULT (phi);
6604 value_range_t *lhs_vr = get_value_range (lhs);
6605 value_range_t vr_result = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
6606 int edges, old_edges;
6609 if (dump_file && (dump_flags & TDF_DETAILS))
6611 fprintf (dump_file, "\nVisiting PHI node: ");
6612 print_gimple_stmt (dump_file, phi, 0, dump_flags);
6616 for (i = 0; i < gimple_phi_num_args (phi); i++)
6618 edge e = gimple_phi_arg_edge (phi, i);
6620 if (dump_file && (dump_flags & TDF_DETAILS))
6623 "\n Argument #%d (%d -> %d %sexecutable)\n",
6624 (int) i, e->src->index, e->dest->index,
6625 (e->flags & EDGE_EXECUTABLE) ? "" : "not ");
6628 if (e->flags & EDGE_EXECUTABLE)
6630 tree arg = PHI_ARG_DEF (phi, i);
6631 value_range_t vr_arg;
6635 if (TREE_CODE (arg) == SSA_NAME)
6637 vr_arg = *(get_value_range (arg));
6641 if (is_overflow_infinity (arg))
6643 arg = copy_node (arg);
6644 TREE_OVERFLOW (arg) = 0;
6647 vr_arg.type = VR_RANGE;
6650 vr_arg.equiv = NULL;
6653 if (dump_file && (dump_flags & TDF_DETAILS))
6655 fprintf (dump_file, "\t");
6656 print_generic_expr (dump_file, arg, dump_flags);
6657 fprintf (dump_file, "\n\tValue: ");
6658 dump_value_range (dump_file, &vr_arg);
6659 fprintf (dump_file, "\n");
6662 vrp_meet (&vr_result, &vr_arg);
6664 if (vr_result.type == VR_VARYING)
6669 if (vr_result.type == VR_VARYING)
6672 old_edges = vr_phi_edge_counts[SSA_NAME_VERSION (lhs)];
6673 vr_phi_edge_counts[SSA_NAME_VERSION (lhs)] = edges;
6675 /* To prevent infinite iterations in the algorithm, derive ranges
6676 when the new value is slightly bigger or smaller than the
6677 previous one. We don't do this if we have seen a new executable
6678 edge; this helps us avoid an overflow infinity for conditionals
6679 which are not in a loop. */
6681 && gimple_phi_num_args (phi) > 1
6682 && edges == old_edges)
6684 int cmp_min = compare_values (lhs_vr->min, vr_result.min);
6685 int cmp_max = compare_values (lhs_vr->max, vr_result.max);
6687 /* For non VR_RANGE or for pointers fall back to varying if
6688 the range changed. */
6689 if ((lhs_vr->type != VR_RANGE || vr_result.type != VR_RANGE
6690 || POINTER_TYPE_P (TREE_TYPE (lhs)))
6691 && (cmp_min != 0 || cmp_max != 0))
6694 /* If the new minimum is smaller or larger than the previous
6695 one, go all the way to -INF. In the first case, to avoid
6696 iterating millions of times to reach -INF, and in the
6697 other case to avoid infinite bouncing between different
6699 if (cmp_min > 0 || cmp_min < 0)
6701 if (!needs_overflow_infinity (TREE_TYPE (vr_result.min))
6702 || !vrp_var_may_overflow (lhs, phi))
6703 vr_result.min = TYPE_MIN_VALUE (TREE_TYPE (vr_result.min));
6704 else if (supports_overflow_infinity (TREE_TYPE (vr_result.min)))
6706 negative_overflow_infinity (TREE_TYPE (vr_result.min));
6709 /* Similarly, if the new maximum is smaller or larger than
6710 the previous one, go all the way to +INF. */
6711 if (cmp_max < 0 || cmp_max > 0)
6713 if (!needs_overflow_infinity (TREE_TYPE (vr_result.max))
6714 || !vrp_var_may_overflow (lhs, phi))
6715 vr_result.max = TYPE_MAX_VALUE (TREE_TYPE (vr_result.max));
6716 else if (supports_overflow_infinity (TREE_TYPE (vr_result.max)))
6718 positive_overflow_infinity (TREE_TYPE (vr_result.max));
6721 /* If we dropped either bound to +-INF then if this is a loop
6722 PHI node SCEV may known more about its value-range. */
6723 if ((cmp_min > 0 || cmp_min < 0
6724 || cmp_max < 0 || cmp_max > 0)
6726 && (l = loop_containing_stmt (phi))
6727 && l->header == gimple_bb (phi))
6728 adjust_range_with_scev (&vr_result, l, phi, lhs);
6730 /* If we will end up with a (-INF, +INF) range, set it to
6731 VARYING. Same if the previous max value was invalid for
6732 the type and we end up with vr_result.min > vr_result.max. */
6733 if ((vrp_val_is_max (vr_result.max)
6734 && vrp_val_is_min (vr_result.min))
6735 || compare_values (vr_result.min,
6740 /* If the new range is different than the previous value, keep
6742 if (update_value_range (lhs, &vr_result))
6744 if (dump_file && (dump_flags & TDF_DETAILS))
6746 fprintf (dump_file, "Found new range for ");
6747 print_generic_expr (dump_file, lhs, 0);
6748 fprintf (dump_file, ": ");
6749 dump_value_range (dump_file, &vr_result);
6750 fprintf (dump_file, "\n\n");
6753 return SSA_PROP_INTERESTING;
6756 /* Nothing changed, don't add outgoing edges. */
6757 return SSA_PROP_NOT_INTERESTING;
6759 /* No match found. Set the LHS to VARYING. */
6761 set_value_range_to_varying (lhs_vr);
6762 return SSA_PROP_VARYING;
6765 /* Simplify boolean operations if the source is known
6766 to be already a boolean. */
6768 simplify_truth_ops_using_ranges (gimple_stmt_iterator *gsi, gimple stmt)
6770 enum tree_code rhs_code = gimple_assign_rhs_code (stmt);
6775 bool need_conversion;
6777 op0 = gimple_assign_rhs1 (stmt);
6778 if (TYPE_PRECISION (TREE_TYPE (op0)) != 1)
6780 if (TREE_CODE (op0) != SSA_NAME)
6782 vr = get_value_range (op0);
6784 val = compare_range_with_value (GE_EXPR, vr, integer_zero_node, &sop);
6785 if (!val || !integer_onep (val))
6788 val = compare_range_with_value (LE_EXPR, vr, integer_one_node, &sop);
6789 if (!val || !integer_onep (val))
6793 if (rhs_code == TRUTH_NOT_EXPR)
6796 op1 = build_int_cst (TREE_TYPE (op0), 1);
6800 op1 = gimple_assign_rhs2 (stmt);
6802 /* Reduce number of cases to handle. */
6803 if (is_gimple_min_invariant (op1))
6805 /* Exclude anything that should have been already folded. */
6806 if (rhs_code != EQ_EXPR
6807 && rhs_code != NE_EXPR
6808 && rhs_code != TRUTH_XOR_EXPR)
6811 if (!integer_zerop (op1)
6812 && !integer_onep (op1)
6813 && !integer_all_onesp (op1))
6816 /* Limit the number of cases we have to consider. */
6817 if (rhs_code == EQ_EXPR)
6820 op1 = fold_unary (TRUTH_NOT_EXPR, TREE_TYPE (op1), op1);
6825 /* Punt on A == B as there is no BIT_XNOR_EXPR. */
6826 if (rhs_code == EQ_EXPR)
6829 if (TYPE_PRECISION (TREE_TYPE (op1)) != 1)
6831 vr = get_value_range (op1);
6832 val = compare_range_with_value (GE_EXPR, vr, integer_zero_node, &sop);
6833 if (!val || !integer_onep (val))
6836 val = compare_range_with_value (LE_EXPR, vr, integer_one_node, &sop);
6837 if (!val || !integer_onep (val))
6843 if (sop && issue_strict_overflow_warning (WARN_STRICT_OVERFLOW_MISC))
6845 location_t location;
6847 if (!gimple_has_location (stmt))
6848 location = input_location;
6850 location = gimple_location (stmt);
6852 if (rhs_code == TRUTH_AND_EXPR || rhs_code == TRUTH_OR_EXPR)
6853 warning_at (location, OPT_Wstrict_overflow,
6854 _("assuming signed overflow does not occur when "
6855 "simplifying && or || to & or |"));
6857 warning_at (location, OPT_Wstrict_overflow,
6858 _("assuming signed overflow does not occur when "
6859 "simplifying ==, != or ! to identity or ^"));
6863 !useless_type_conversion_p (TREE_TYPE (gimple_assign_lhs (stmt)),
6866 /* Make sure to not sign-extend -1 as a boolean value. */
6868 && !TYPE_UNSIGNED (TREE_TYPE (op0))
6869 && TYPE_PRECISION (TREE_TYPE (op0)) == 1)
6874 case TRUTH_AND_EXPR:
6875 rhs_code = BIT_AND_EXPR;
6878 rhs_code = BIT_IOR_EXPR;
6880 case TRUTH_XOR_EXPR:
6882 if (integer_zerop (op1))
6884 gimple_assign_set_rhs_with_ops (gsi,
6885 need_conversion ? NOP_EXPR : SSA_NAME,
6887 update_stmt (gsi_stmt (*gsi));
6891 rhs_code = BIT_XOR_EXPR;
6897 if (need_conversion)
6900 gimple_assign_set_rhs_with_ops (gsi, rhs_code, op0, op1);
6901 update_stmt (gsi_stmt (*gsi));
6905 /* Simplify a division or modulo operator to a right shift or
6906 bitwise and if the first operand is unsigned or is greater
6907 than zero and the second operand is an exact power of two. */
6910 simplify_div_or_mod_using_ranges (gimple stmt)
6912 enum tree_code rhs_code = gimple_assign_rhs_code (stmt);
6914 tree op0 = gimple_assign_rhs1 (stmt);
6915 tree op1 = gimple_assign_rhs2 (stmt);
6916 value_range_t *vr = get_value_range (gimple_assign_rhs1 (stmt));
6918 if (TYPE_UNSIGNED (TREE_TYPE (op0)))
6920 val = integer_one_node;
6926 val = compare_range_with_value (GE_EXPR, vr, integer_zero_node, &sop);
6930 && integer_onep (val)
6931 && issue_strict_overflow_warning (WARN_STRICT_OVERFLOW_MISC))
6933 location_t location;
6935 if (!gimple_has_location (stmt))
6936 location = input_location;
6938 location = gimple_location (stmt);
6939 warning_at (location, OPT_Wstrict_overflow,
6940 "assuming signed overflow does not occur when "
6941 "simplifying %</%> or %<%%%> to %<>>%> or %<&%>");
6945 if (val && integer_onep (val))
6949 if (rhs_code == TRUNC_DIV_EXPR)
6951 t = build_int_cst (integer_type_node, tree_log2 (op1));
6952 gimple_assign_set_rhs_code (stmt, RSHIFT_EXPR);
6953 gimple_assign_set_rhs1 (stmt, op0);
6954 gimple_assign_set_rhs2 (stmt, t);
6958 t = build_int_cst (TREE_TYPE (op1), 1);
6959 t = int_const_binop (MINUS_EXPR, op1, t);
6960 t = fold_convert (TREE_TYPE (op0), t);
6962 gimple_assign_set_rhs_code (stmt, BIT_AND_EXPR);
6963 gimple_assign_set_rhs1 (stmt, op0);
6964 gimple_assign_set_rhs2 (stmt, t);
6974 /* If the operand to an ABS_EXPR is >= 0, then eliminate the
6975 ABS_EXPR. If the operand is <= 0, then simplify the
6976 ABS_EXPR into a NEGATE_EXPR. */
6979 simplify_abs_using_ranges (gimple stmt)
6982 tree op = gimple_assign_rhs1 (stmt);
6983 tree type = TREE_TYPE (op);
6984 value_range_t *vr = get_value_range (op);
6986 if (TYPE_UNSIGNED (type))
6988 val = integer_zero_node;
6994 val = compare_range_with_value (LE_EXPR, vr, integer_zero_node, &sop);
6998 val = compare_range_with_value (GE_EXPR, vr, integer_zero_node,
7003 if (integer_zerop (val))
7004 val = integer_one_node;
7005 else if (integer_onep (val))
7006 val = integer_zero_node;
7011 && (integer_onep (val) || integer_zerop (val)))
7013 if (sop && issue_strict_overflow_warning (WARN_STRICT_OVERFLOW_MISC))
7015 location_t location;
7017 if (!gimple_has_location (stmt))
7018 location = input_location;
7020 location = gimple_location (stmt);
7021 warning_at (location, OPT_Wstrict_overflow,
7022 "assuming signed overflow does not occur when "
7023 "simplifying %<abs (X)%> to %<X%> or %<-X%>");
7026 gimple_assign_set_rhs1 (stmt, op);
7027 if (integer_onep (val))
7028 gimple_assign_set_rhs_code (stmt, NEGATE_EXPR);
7030 gimple_assign_set_rhs_code (stmt, SSA_NAME);
7039 /* Optimize away redundant BIT_AND_EXPR and BIT_IOR_EXPR.
7040 If all the bits that are being cleared by & are already
7041 known to be zero from VR, or all the bits that are being
7042 set by | are already known to be one from VR, the bit
7043 operation is redundant. */
7046 simplify_bit_ops_using_ranges (gimple_stmt_iterator *gsi, gimple stmt)
7048 tree op0 = gimple_assign_rhs1 (stmt);
7049 tree op1 = gimple_assign_rhs2 (stmt);
7050 tree op = NULL_TREE;
7051 value_range_t vr0 = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
7052 value_range_t vr1 = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
7053 double_int may_be_nonzero0, may_be_nonzero1;
7054 double_int must_be_nonzero0, must_be_nonzero1;
7057 if (TREE_CODE (op0) == SSA_NAME)
7058 vr0 = *(get_value_range (op0));
7059 else if (is_gimple_min_invariant (op0))
7060 set_value_range_to_value (&vr0, op0, NULL);
7064 if (TREE_CODE (op1) == SSA_NAME)
7065 vr1 = *(get_value_range (op1));
7066 else if (is_gimple_min_invariant (op1))
7067 set_value_range_to_value (&vr1, op1, NULL);
7071 if (!zero_nonzero_bits_from_vr (&vr0, &may_be_nonzero0, &must_be_nonzero0))
7073 if (!zero_nonzero_bits_from_vr (&vr1, &may_be_nonzero1, &must_be_nonzero1))
7076 switch (gimple_assign_rhs_code (stmt))
7079 mask = double_int_and_not (may_be_nonzero0, must_be_nonzero1);
7080 if (double_int_zero_p (mask))
7085 mask = double_int_and_not (may_be_nonzero1, must_be_nonzero0);
7086 if (double_int_zero_p (mask))
7093 mask = double_int_and_not (may_be_nonzero0, must_be_nonzero1);
7094 if (double_int_zero_p (mask))
7099 mask = double_int_and_not (may_be_nonzero1, must_be_nonzero0);
7100 if (double_int_zero_p (mask))
7110 if (op == NULL_TREE)
7113 gimple_assign_set_rhs_with_ops (gsi, TREE_CODE (op), op, NULL);
7114 update_stmt (gsi_stmt (*gsi));
7118 /* We are comparing trees OP0 and OP1 using COND_CODE. OP0 has
7119 a known value range VR.
7121 If there is one and only one value which will satisfy the
7122 conditional, then return that value. Else return NULL. */
7125 test_for_singularity (enum tree_code cond_code, tree op0,
7126 tree op1, value_range_t *vr)
7131 /* Extract minimum/maximum values which satisfy the
7132 the conditional as it was written. */
7133 if (cond_code == LE_EXPR || cond_code == LT_EXPR)
7135 /* This should not be negative infinity; there is no overflow
7137 min = TYPE_MIN_VALUE (TREE_TYPE (op0));
7140 if (cond_code == LT_EXPR && !is_overflow_infinity (max))
7142 tree one = build_int_cst (TREE_TYPE (op0), 1);
7143 max = fold_build2 (MINUS_EXPR, TREE_TYPE (op0), max, one);
7145 TREE_NO_WARNING (max) = 1;
7148 else if (cond_code == GE_EXPR || cond_code == GT_EXPR)
7150 /* This should not be positive infinity; there is no overflow
7152 max = TYPE_MAX_VALUE (TREE_TYPE (op0));
7155 if (cond_code == GT_EXPR && !is_overflow_infinity (min))
7157 tree one = build_int_cst (TREE_TYPE (op0), 1);
7158 min = fold_build2 (PLUS_EXPR, TREE_TYPE (op0), min, one);
7160 TREE_NO_WARNING (min) = 1;
7164 /* Now refine the minimum and maximum values using any
7165 value range information we have for op0. */
7168 if (compare_values (vr->min, min) == 1)
7170 if (compare_values (vr->max, max) == -1)
7173 /* If the new min/max values have converged to a single value,
7174 then there is only one value which can satisfy the condition,
7175 return that value. */
7176 if (operand_equal_p (min, max, 0) && is_gimple_min_invariant (min))
7182 /* Simplify a conditional using a relational operator to an equality
7183 test if the range information indicates only one value can satisfy
7184 the original conditional. */
7187 simplify_cond_using_ranges (gimple stmt)
7189 tree op0 = gimple_cond_lhs (stmt);
7190 tree op1 = gimple_cond_rhs (stmt);
7191 enum tree_code cond_code = gimple_cond_code (stmt);
7193 if (cond_code != NE_EXPR
7194 && cond_code != EQ_EXPR
7195 && TREE_CODE (op0) == SSA_NAME
7196 && INTEGRAL_TYPE_P (TREE_TYPE (op0))
7197 && is_gimple_min_invariant (op1))
7199 value_range_t *vr = get_value_range (op0);
7201 /* If we have range information for OP0, then we might be
7202 able to simplify this conditional. */
7203 if (vr->type == VR_RANGE)
7205 tree new_tree = test_for_singularity (cond_code, op0, op1, vr);
7211 fprintf (dump_file, "Simplified relational ");
7212 print_gimple_stmt (dump_file, stmt, 0, 0);
7213 fprintf (dump_file, " into ");
7216 gimple_cond_set_code (stmt, EQ_EXPR);
7217 gimple_cond_set_lhs (stmt, op0);
7218 gimple_cond_set_rhs (stmt, new_tree);
7224 print_gimple_stmt (dump_file, stmt, 0, 0);
7225 fprintf (dump_file, "\n");
7231 /* Try again after inverting the condition. We only deal
7232 with integral types here, so no need to worry about
7233 issues with inverting FP comparisons. */
7234 cond_code = invert_tree_comparison (cond_code, false);
7235 new_tree = test_for_singularity (cond_code, op0, op1, vr);
7241 fprintf (dump_file, "Simplified relational ");
7242 print_gimple_stmt (dump_file, stmt, 0, 0);
7243 fprintf (dump_file, " into ");
7246 gimple_cond_set_code (stmt, NE_EXPR);
7247 gimple_cond_set_lhs (stmt, op0);
7248 gimple_cond_set_rhs (stmt, new_tree);
7254 print_gimple_stmt (dump_file, stmt, 0, 0);
7255 fprintf (dump_file, "\n");
7266 /* Simplify a switch statement using the value range of the switch
7270 simplify_switch_using_ranges (gimple stmt)
7272 tree op = gimple_switch_index (stmt);
7277 size_t i = 0, j = 0, n, n2;
7281 if (TREE_CODE (op) == SSA_NAME)
7283 vr = get_value_range (op);
7285 /* We can only handle integer ranges. */
7286 if (vr->type != VR_RANGE
7287 || symbolic_range_p (vr))
7290 /* Find case label for min/max of the value range. */
7291 take_default = !find_case_label_range (stmt, vr->min, vr->max, &i, &j);
7293 else if (TREE_CODE (op) == INTEGER_CST)
7295 take_default = !find_case_label_index (stmt, 1, op, &i);
7309 n = gimple_switch_num_labels (stmt);
7311 /* Bail out if this is just all edges taken. */
7317 /* Build a new vector of taken case labels. */
7318 vec2 = make_tree_vec (j - i + 1 + (int)take_default);
7321 /* Add the default edge, if necessary. */
7323 TREE_VEC_ELT (vec2, n2++) = gimple_switch_default_label (stmt);
7325 for (; i <= j; ++i, ++n2)
7326 TREE_VEC_ELT (vec2, n2) = gimple_switch_label (stmt, i);
7328 /* Mark needed edges. */
7329 for (i = 0; i < n2; ++i)
7331 e = find_edge (gimple_bb (stmt),
7332 label_to_block (CASE_LABEL (TREE_VEC_ELT (vec2, i))));
7333 e->aux = (void *)-1;
7336 /* Queue not needed edges for later removal. */
7337 FOR_EACH_EDGE (e, ei, gimple_bb (stmt)->succs)
7339 if (e->aux == (void *)-1)
7345 if (dump_file && (dump_flags & TDF_DETAILS))
7347 fprintf (dump_file, "removing unreachable case label\n");
7349 VEC_safe_push (edge, heap, to_remove_edges, e);
7350 e->flags &= ~EDGE_EXECUTABLE;
7353 /* And queue an update for the stmt. */
7356 VEC_safe_push (switch_update, heap, to_update_switch_stmts, &su);
7360 /* Simplify an integral conversion from an SSA name in STMT. */
7363 simplify_conversion_using_ranges (gimple stmt)
7365 tree innerop, middleop, finaltype;
7367 value_range_t *innervr;
7368 double_int innermin, innermax, middlemin, middlemax;
7370 finaltype = TREE_TYPE (gimple_assign_lhs (stmt));
7371 if (!INTEGRAL_TYPE_P (finaltype))
7373 middleop = gimple_assign_rhs1 (stmt);
7374 def_stmt = SSA_NAME_DEF_STMT (middleop);
7375 if (!is_gimple_assign (def_stmt)
7376 || !CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (def_stmt)))
7378 innerop = gimple_assign_rhs1 (def_stmt);
7379 if (TREE_CODE (innerop) != SSA_NAME)
7382 /* Get the value-range of the inner operand. */
7383 innervr = get_value_range (innerop);
7384 if (innervr->type != VR_RANGE
7385 || TREE_CODE (innervr->min) != INTEGER_CST
7386 || TREE_CODE (innervr->max) != INTEGER_CST)
7389 /* Simulate the conversion chain to check if the result is equal if
7390 the middle conversion is removed. */
7391 innermin = tree_to_double_int (innervr->min);
7392 innermax = tree_to_double_int (innervr->max);
7393 middlemin = double_int_ext (innermin, TYPE_PRECISION (TREE_TYPE (middleop)),
7394 TYPE_UNSIGNED (TREE_TYPE (middleop)));
7395 middlemax = double_int_ext (innermax, TYPE_PRECISION (TREE_TYPE (middleop)),
7396 TYPE_UNSIGNED (TREE_TYPE (middleop)));
7397 /* If the middle values do not represent a proper range fail. */
7398 if (double_int_cmp (middlemin, middlemax,
7399 TYPE_UNSIGNED (TREE_TYPE (middleop))) > 0)
7401 if (!double_int_equal_p (double_int_ext (middlemin,
7402 TYPE_PRECISION (finaltype),
7403 TYPE_UNSIGNED (finaltype)),
7404 double_int_ext (innermin,
7405 TYPE_PRECISION (finaltype),
7406 TYPE_UNSIGNED (finaltype)))
7407 || !double_int_equal_p (double_int_ext (middlemax,
7408 TYPE_PRECISION (finaltype),
7409 TYPE_UNSIGNED (finaltype)),
7410 double_int_ext (innermax,
7411 TYPE_PRECISION (finaltype),
7412 TYPE_UNSIGNED (finaltype))))
7415 gimple_assign_set_rhs1 (stmt, innerop);
7420 /* Return whether the value range *VR fits in an integer type specified
7421 by PRECISION and UNSIGNED_P. */
7424 range_fits_type_p (value_range_t *vr, unsigned precision, bool unsigned_p)
7428 /* We can only handle constant ranges. */
7429 if (vr->type != VR_RANGE
7430 || TREE_CODE (vr->min) != INTEGER_CST
7431 || TREE_CODE (vr->max) != INTEGER_CST)
7434 tem = double_int_ext (tree_to_double_int (vr->min), precision, unsigned_p);
7435 if (!double_int_equal_p (tree_to_double_int (vr->min), tem))
7438 tem = double_int_ext (tree_to_double_int (vr->max), precision, unsigned_p);
7439 if (!double_int_equal_p (tree_to_double_int (vr->max), tem))
7445 /* Simplify a conversion from integral SSA name to float in STMT. */
7448 simplify_float_conversion_using_ranges (gimple_stmt_iterator *gsi, gimple stmt)
7450 tree rhs1 = gimple_assign_rhs1 (stmt);
7451 value_range_t *vr = get_value_range (rhs1);
7452 enum machine_mode fltmode = TYPE_MODE (TREE_TYPE (gimple_assign_lhs (stmt)));
7453 enum machine_mode mode;
7457 /* We can only handle constant ranges. */
7458 if (vr->type != VR_RANGE
7459 || TREE_CODE (vr->min) != INTEGER_CST
7460 || TREE_CODE (vr->max) != INTEGER_CST)
7463 /* First check if we can use a signed type in place of an unsigned. */
7464 if (TYPE_UNSIGNED (TREE_TYPE (rhs1))
7465 && (can_float_p (fltmode, TYPE_MODE (TREE_TYPE (rhs1)), 0)
7466 != CODE_FOR_nothing)
7467 && range_fits_type_p (vr, GET_MODE_PRECISION
7468 (TYPE_MODE (TREE_TYPE (rhs1))), 0))
7469 mode = TYPE_MODE (TREE_TYPE (rhs1));
7470 /* If we can do the conversion in the current input mode do nothing. */
7471 else if (can_float_p (fltmode, TYPE_MODE (TREE_TYPE (rhs1)),
7472 TYPE_UNSIGNED (TREE_TYPE (rhs1))))
7474 /* Otherwise search for a mode we can use, starting from the narrowest
7475 integer mode available. */
7478 mode = GET_CLASS_NARROWEST_MODE (MODE_INT);
7481 /* If we cannot do a signed conversion to float from mode
7482 or if the value-range does not fit in the signed type
7483 try with a wider mode. */
7484 if (can_float_p (fltmode, mode, 0) != CODE_FOR_nothing
7485 && range_fits_type_p (vr, GET_MODE_PRECISION (mode), 0))
7488 mode = GET_MODE_WIDER_MODE (mode);
7489 /* But do not widen the input. Instead leave that to the
7490 optabs expansion code. */
7491 if (GET_MODE_PRECISION (mode) > TYPE_PRECISION (TREE_TYPE (rhs1)))
7494 while (mode != VOIDmode);
7495 if (mode == VOIDmode)
7499 /* It works, insert a truncation or sign-change before the
7500 float conversion. */
7501 tem = create_tmp_var (build_nonstandard_integer_type
7502 (GET_MODE_PRECISION (mode), 0), NULL);
7503 conv = gimple_build_assign_with_ops (NOP_EXPR, tem, rhs1, NULL_TREE);
7504 tem = make_ssa_name (tem, conv);
7505 gimple_assign_set_lhs (conv, tem);
7506 gsi_insert_before (gsi, conv, GSI_SAME_STMT);
7507 gimple_assign_set_rhs1 (stmt, tem);
7513 /* Simplify STMT using ranges if possible. */
7516 simplify_stmt_using_ranges (gimple_stmt_iterator *gsi)
7518 gimple stmt = gsi_stmt (*gsi);
7519 if (is_gimple_assign (stmt))
7521 enum tree_code rhs_code = gimple_assign_rhs_code (stmt);
7522 tree rhs1 = gimple_assign_rhs1 (stmt);
7528 case TRUTH_NOT_EXPR:
7529 case TRUTH_AND_EXPR:
7531 case TRUTH_XOR_EXPR:
7532 /* Transform EQ_EXPR, NE_EXPR, TRUTH_NOT_EXPR into BIT_XOR_EXPR
7533 or identity if the RHS is zero or one, and the LHS are known
7534 to be boolean values. Transform all TRUTH_*_EXPR into
7535 BIT_*_EXPR if both arguments are known to be boolean values. */
7536 if (INTEGRAL_TYPE_P (TREE_TYPE (rhs1)))
7537 return simplify_truth_ops_using_ranges (gsi, stmt);
7540 /* Transform TRUNC_DIV_EXPR and TRUNC_MOD_EXPR into RSHIFT_EXPR
7541 and BIT_AND_EXPR respectively if the first operand is greater
7542 than zero and the second operand is an exact power of two. */
7543 case TRUNC_DIV_EXPR:
7544 case TRUNC_MOD_EXPR:
7545 if (INTEGRAL_TYPE_P (TREE_TYPE (rhs1))
7546 && integer_pow2p (gimple_assign_rhs2 (stmt)))
7547 return simplify_div_or_mod_using_ranges (stmt);
7550 /* Transform ABS (X) into X or -X as appropriate. */
7552 if (TREE_CODE (rhs1) == SSA_NAME
7553 && INTEGRAL_TYPE_P (TREE_TYPE (rhs1)))
7554 return simplify_abs_using_ranges (stmt);
7559 /* Optimize away BIT_AND_EXPR and BIT_IOR_EXPR
7560 if all the bits being cleared are already cleared or
7561 all the bits being set are already set. */
7562 if (INTEGRAL_TYPE_P (TREE_TYPE (rhs1)))
7563 return simplify_bit_ops_using_ranges (gsi, stmt);
7567 if (TREE_CODE (rhs1) == SSA_NAME
7568 && INTEGRAL_TYPE_P (TREE_TYPE (rhs1)))
7569 return simplify_conversion_using_ranges (stmt);
7573 if (TREE_CODE (rhs1) == SSA_NAME
7574 && INTEGRAL_TYPE_P (TREE_TYPE (rhs1)))
7575 return simplify_float_conversion_using_ranges (gsi, stmt);
7582 else if (gimple_code (stmt) == GIMPLE_COND)
7583 return simplify_cond_using_ranges (stmt);
7584 else if (gimple_code (stmt) == GIMPLE_SWITCH)
7585 return simplify_switch_using_ranges (stmt);
7590 /* If the statement pointed by SI has a predicate whose value can be
7591 computed using the value range information computed by VRP, compute
7592 its value and return true. Otherwise, return false. */
7595 fold_predicate_in (gimple_stmt_iterator *si)
7597 bool assignment_p = false;
7599 gimple stmt = gsi_stmt (*si);
7601 if (is_gimple_assign (stmt)
7602 && TREE_CODE_CLASS (gimple_assign_rhs_code (stmt)) == tcc_comparison)
7604 assignment_p = true;
7605 val = vrp_evaluate_conditional (gimple_assign_rhs_code (stmt),
7606 gimple_assign_rhs1 (stmt),
7607 gimple_assign_rhs2 (stmt),
7610 else if (gimple_code (stmt) == GIMPLE_COND)
7611 val = vrp_evaluate_conditional (gimple_cond_code (stmt),
7612 gimple_cond_lhs (stmt),
7613 gimple_cond_rhs (stmt),
7621 val = fold_convert (gimple_expr_type (stmt), val);
7625 fprintf (dump_file, "Folding predicate ");
7626 print_gimple_expr (dump_file, stmt, 0, 0);
7627 fprintf (dump_file, " to ");
7628 print_generic_expr (dump_file, val, 0);
7629 fprintf (dump_file, "\n");
7632 if (is_gimple_assign (stmt))
7633 gimple_assign_set_rhs_from_tree (si, val);
7636 gcc_assert (gimple_code (stmt) == GIMPLE_COND);
7637 if (integer_zerop (val))
7638 gimple_cond_make_false (stmt);
7639 else if (integer_onep (val))
7640 gimple_cond_make_true (stmt);
7651 /* Callback for substitute_and_fold folding the stmt at *SI. */
7654 vrp_fold_stmt (gimple_stmt_iterator *si)
7656 if (fold_predicate_in (si))
7659 return simplify_stmt_using_ranges (si);
7662 /* Stack of dest,src equivalency pairs that need to be restored after
7663 each attempt to thread a block's incoming edge to an outgoing edge.
7665 A NULL entry is used to mark the end of pairs which need to be
7667 static VEC(tree,heap) *stack;
7669 /* A trivial wrapper so that we can present the generic jump threading
7670 code with a simple API for simplifying statements. STMT is the
7671 statement we want to simplify, WITHIN_STMT provides the location
7672 for any overflow warnings. */
7675 simplify_stmt_for_jump_threading (gimple stmt, gimple within_stmt)
7677 /* We only use VRP information to simplify conditionals. This is
7678 overly conservative, but it's unclear if doing more would be
7679 worth the compile time cost. */
7680 if (gimple_code (stmt) != GIMPLE_COND)
7683 return vrp_evaluate_conditional (gimple_cond_code (stmt),
7684 gimple_cond_lhs (stmt),
7685 gimple_cond_rhs (stmt), within_stmt);
7688 /* Blocks which have more than one predecessor and more than
7689 one successor present jump threading opportunities, i.e.,
7690 when the block is reached from a specific predecessor, we
7691 may be able to determine which of the outgoing edges will
7692 be traversed. When this optimization applies, we are able
7693 to avoid conditionals at runtime and we may expose secondary
7694 optimization opportunities.
7696 This routine is effectively a driver for the generic jump
7697 threading code. It basically just presents the generic code
7698 with edges that may be suitable for jump threading.
7700 Unlike DOM, we do not iterate VRP if jump threading was successful.
7701 While iterating may expose new opportunities for VRP, it is expected
7702 those opportunities would be very limited and the compile time cost
7703 to expose those opportunities would be significant.
7705 As jump threading opportunities are discovered, they are registered
7706 for later realization. */
7709 identify_jump_threads (void)
7716 /* Ugh. When substituting values earlier in this pass we can
7717 wipe the dominance information. So rebuild the dominator
7718 information as we need it within the jump threading code. */
7719 calculate_dominance_info (CDI_DOMINATORS);
7721 /* We do not allow VRP information to be used for jump threading
7722 across a back edge in the CFG. Otherwise it becomes too
7723 difficult to avoid eliminating loop exit tests. Of course
7724 EDGE_DFS_BACK is not accurate at this time so we have to
7726 mark_dfs_back_edges ();
7728 /* Do not thread across edges we are about to remove. Just marking
7729 them as EDGE_DFS_BACK will do. */
7730 FOR_EACH_VEC_ELT (edge, to_remove_edges, i, e)
7731 e->flags |= EDGE_DFS_BACK;
7733 /* Allocate our unwinder stack to unwind any temporary equivalences
7734 that might be recorded. */
7735 stack = VEC_alloc (tree, heap, 20);
7737 /* To avoid lots of silly node creation, we create a single
7738 conditional and just modify it in-place when attempting to
7740 dummy = gimple_build_cond (EQ_EXPR,
7741 integer_zero_node, integer_zero_node,
7744 /* Walk through all the blocks finding those which present a
7745 potential jump threading opportunity. We could set this up
7746 as a dominator walker and record data during the walk, but
7747 I doubt it's worth the effort for the classes of jump
7748 threading opportunities we are trying to identify at this
7749 point in compilation. */
7754 /* If the generic jump threading code does not find this block
7755 interesting, then there is nothing to do. */
7756 if (! potentially_threadable_block (bb))
7759 /* We only care about blocks ending in a COND_EXPR. While there
7760 may be some value in handling SWITCH_EXPR here, I doubt it's
7761 terribly important. */
7762 last = gsi_stmt (gsi_last_bb (bb));
7764 /* We're basically looking for a switch or any kind of conditional with
7765 integral or pointer type arguments. Note the type of the second
7766 argument will be the same as the first argument, so no need to
7767 check it explicitly. */
7768 if (gimple_code (last) == GIMPLE_SWITCH
7769 || (gimple_code (last) == GIMPLE_COND
7770 && TREE_CODE (gimple_cond_lhs (last)) == SSA_NAME
7771 && (INTEGRAL_TYPE_P (TREE_TYPE (gimple_cond_lhs (last)))
7772 || POINTER_TYPE_P (TREE_TYPE (gimple_cond_lhs (last))))
7773 && (TREE_CODE (gimple_cond_rhs (last)) == SSA_NAME
7774 || is_gimple_min_invariant (gimple_cond_rhs (last)))))
7778 /* We've got a block with multiple predecessors and multiple
7779 successors which also ends in a suitable conditional or
7780 switch statement. For each predecessor, see if we can thread
7781 it to a specific successor. */
7782 FOR_EACH_EDGE (e, ei, bb->preds)
7784 /* Do not thread across back edges or abnormal edges
7786 if (e->flags & (EDGE_DFS_BACK | EDGE_COMPLEX))
7789 thread_across_edge (dummy, e, true, &stack,
7790 simplify_stmt_for_jump_threading);
7795 /* We do not actually update the CFG or SSA graphs at this point as
7796 ASSERT_EXPRs are still in the IL and cfg cleanup code does not yet
7797 handle ASSERT_EXPRs gracefully. */
7800 /* We identified all the jump threading opportunities earlier, but could
7801 not transform the CFG at that time. This routine transforms the
7802 CFG and arranges for the dominator tree to be rebuilt if necessary.
7804 Note the SSA graph update will occur during the normal TODO
7805 processing by the pass manager. */
7807 finalize_jump_threads (void)
7809 thread_through_all_blocks (false);
7810 VEC_free (tree, heap, stack);
7814 /* Traverse all the blocks folding conditionals with known ranges. */
7821 values_propagated = true;
7825 fprintf (dump_file, "\nValue ranges after VRP:\n\n");
7826 dump_all_value_ranges (dump_file);
7827 fprintf (dump_file, "\n");
7830 substitute_and_fold (op_with_constant_singleton_value_range,
7831 vrp_fold_stmt, false);
7833 if (warn_array_bounds)
7834 check_all_array_refs ();
7836 /* We must identify jump threading opportunities before we release
7837 the datastructures built by VRP. */
7838 identify_jump_threads ();
7840 /* Free allocated memory. */
7841 for (i = 0; i < num_vr_values; i++)
7844 BITMAP_FREE (vr_value[i]->equiv);
7849 free (vr_phi_edge_counts);
7851 /* So that we can distinguish between VRP data being available
7852 and not available. */
7854 vr_phi_edge_counts = NULL;
7858 /* Main entry point to VRP (Value Range Propagation). This pass is
7859 loosely based on J. R. C. Patterson, ``Accurate Static Branch
7860 Prediction by Value Range Propagation,'' in SIGPLAN Conference on
7861 Programming Language Design and Implementation, pp. 67-78, 1995.
7862 Also available at http://citeseer.ist.psu.edu/patterson95accurate.html
7864 This is essentially an SSA-CCP pass modified to deal with ranges
7865 instead of constants.
7867 While propagating ranges, we may find that two or more SSA name
7868 have equivalent, though distinct ranges. For instance,
7871 2 p_4 = ASSERT_EXPR <p_3, p_3 != 0>
7873 4 p_5 = ASSERT_EXPR <p_4, p_4 == q_2>;
7877 In the code above, pointer p_5 has range [q_2, q_2], but from the
7878 code we can also determine that p_5 cannot be NULL and, if q_2 had
7879 a non-varying range, p_5's range should also be compatible with it.
7881 These equivalences are created by two expressions: ASSERT_EXPR and
7882 copy operations. Since p_5 is an assertion on p_4, and p_4 was the
7883 result of another assertion, then we can use the fact that p_5 and
7884 p_4 are equivalent when evaluating p_5's range.
7886 Together with value ranges, we also propagate these equivalences
7887 between names so that we can take advantage of information from
7888 multiple ranges when doing final replacement. Note that this
7889 equivalency relation is transitive but not symmetric.
7891 In the example above, p_5 is equivalent to p_4, q_2 and p_3, but we
7892 cannot assert that q_2 is equivalent to p_5 because q_2 may be used
7893 in contexts where that assertion does not hold (e.g., in line 6).
7895 TODO, the main difference between this pass and Patterson's is that
7896 we do not propagate edge probabilities. We only compute whether
7897 edges can be taken or not. That is, instead of having a spectrum
7898 of jump probabilities between 0 and 1, we only deal with 0, 1 and
7899 DON'T KNOW. In the future, it may be worthwhile to propagate
7900 probabilities to aid branch prediction. */
7909 loop_optimizer_init (LOOPS_NORMAL | LOOPS_HAVE_RECORDED_EXITS);
7910 rewrite_into_loop_closed_ssa (NULL, TODO_update_ssa);
7913 insert_range_assertions ();
7915 /* Estimate number of iterations - but do not use undefined behavior
7916 for this. We can't do this lazily as other functions may compute
7917 this using undefined behavior. */
7918 free_numbers_of_iterations_estimates ();
7919 estimate_numbers_of_iterations (false);
7921 to_remove_edges = VEC_alloc (edge, heap, 10);
7922 to_update_switch_stmts = VEC_alloc (switch_update, heap, 5);
7923 threadedge_initialize_values ();
7926 ssa_propagate (vrp_visit_stmt, vrp_visit_phi_node);
7929 free_numbers_of_iterations_estimates ();
7931 /* ASSERT_EXPRs must be removed before finalizing jump threads
7932 as finalizing jump threads calls the CFG cleanup code which
7933 does not properly handle ASSERT_EXPRs. */
7934 remove_range_assertions ();
7936 /* If we exposed any new variables, go ahead and put them into
7937 SSA form now, before we handle jump threading. This simplifies
7938 interactions between rewriting of _DECL nodes into SSA form
7939 and rewriting SSA_NAME nodes into SSA form after block
7940 duplication and CFG manipulation. */
7941 update_ssa (TODO_update_ssa);
7943 finalize_jump_threads ();
7945 /* Remove dead edges from SWITCH_EXPR optimization. This leaves the
7946 CFG in a broken state and requires a cfg_cleanup run. */
7947 FOR_EACH_VEC_ELT (edge, to_remove_edges, i, e)
7949 /* Update SWITCH_EXPR case label vector. */
7950 FOR_EACH_VEC_ELT (switch_update, to_update_switch_stmts, i, su)
7953 size_t n = TREE_VEC_LENGTH (su->vec);
7955 gimple_switch_set_num_labels (su->stmt, n);
7956 for (j = 0; j < n; j++)
7957 gimple_switch_set_label (su->stmt, j, TREE_VEC_ELT (su->vec, j));
7958 /* As we may have replaced the default label with a regular one
7959 make sure to make it a real default label again. This ensures
7960 optimal expansion. */
7961 label = gimple_switch_default_label (su->stmt);
7962 CASE_LOW (label) = NULL_TREE;
7963 CASE_HIGH (label) = NULL_TREE;
7966 if (VEC_length (edge, to_remove_edges) > 0)
7967 free_dominance_info (CDI_DOMINATORS);
7969 VEC_free (edge, heap, to_remove_edges);
7970 VEC_free (switch_update, heap, to_update_switch_stmts);
7971 threadedge_finalize_values ();
7974 loop_optimizer_finalize ();
7981 return flag_tree_vrp != 0;
7984 struct gimple_opt_pass pass_vrp =
7989 gate_vrp, /* gate */
7990 execute_vrp, /* execute */
7993 0, /* static_pass_number */
7994 TV_TREE_VRP, /* tv_id */
7995 PROP_ssa, /* properties_required */
7996 0, /* properties_provided */
7997 0, /* properties_destroyed */
7998 0, /* todo_flags_start */
8003 | TODO_ggc_collect /* todo_flags_finish */