1 /* Support routines for Value Range Propagation (VRP).
2 Copyright (C) 2005, 2006, 2007, 2008, 2009, 2010, 2011
3 Free Software Foundation, Inc.
4 Contributed by Diego Novillo <dnovillo@redhat.com>.
6 This file is part of GCC.
8 GCC is free software; you can redistribute it and/or modify
9 it under the terms of the GNU General Public License as published by
10 the Free Software Foundation; either version 3, or (at your option)
13 GCC is distributed in the hope that it will be useful,
14 but WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 GNU General Public License for more details.
18 You should have received a copy of the GNU General Public License
19 along with GCC; see the file COPYING3. If not see
20 <http://www.gnu.org/licenses/>. */
24 #include "coretypes.h"
29 #include "basic-block.h"
30 #include "tree-flow.h"
31 #include "tree-pass.h"
32 #include "tree-dump.h"
34 #include "tree-pretty-print.h"
35 #include "gimple-pretty-print.h"
36 #include "diagnostic-core.h"
39 #include "tree-scalar-evolution.h"
40 #include "tree-ssa-propagate.h"
41 #include "tree-chrec.h"
42 #include "gimple-fold.h"
47 /* Type of value ranges. See value_range_d for a description of these
49 enum value_range_type { VR_UNDEFINED, VR_RANGE, VR_ANTI_RANGE, VR_VARYING };
51 /* Range of values that can be associated with an SSA_NAME after VRP
55 /* Lattice value represented by this range. */
56 enum value_range_type type;
58 /* Minimum and maximum values represented by this range. These
59 values should be interpreted as follows:
61 - If TYPE is VR_UNDEFINED or VR_VARYING then MIN and MAX must
64 - If TYPE == VR_RANGE then MIN holds the minimum value and
65 MAX holds the maximum value of the range [MIN, MAX].
67 - If TYPE == ANTI_RANGE the variable is known to NOT
68 take any values in the range [MIN, MAX]. */
72 /* Set of SSA names whose value ranges are equivalent to this one.
73 This set is only valid when TYPE is VR_RANGE or VR_ANTI_RANGE. */
77 typedef struct value_range_d value_range_t;
79 /* Set of SSA names found live during the RPO traversal of the function
80 for still active basic-blocks. */
83 /* Return true if the SSA name NAME is live on the edge E. */
86 live_on_edge (edge e, tree name)
88 return (live[e->dest->index]
89 && TEST_BIT (live[e->dest->index], SSA_NAME_VERSION (name)));
92 /* Local functions. */
93 static int compare_values (tree val1, tree val2);
94 static int compare_values_warnv (tree val1, tree val2, bool *);
95 static void vrp_meet (value_range_t *, value_range_t *);
96 static tree vrp_evaluate_conditional_warnv_with_ops (enum tree_code,
97 tree, tree, bool, bool *,
100 /* Location information for ASSERT_EXPRs. Each instance of this
101 structure describes an ASSERT_EXPR for an SSA name. Since a single
102 SSA name may have more than one assertion associated with it, these
103 locations are kept in a linked list attached to the corresponding
105 struct assert_locus_d
107 /* Basic block where the assertion would be inserted. */
110 /* Some assertions need to be inserted on an edge (e.g., assertions
111 generated by COND_EXPRs). In those cases, BB will be NULL. */
114 /* Pointer to the statement that generated this assertion. */
115 gimple_stmt_iterator si;
117 /* Predicate code for the ASSERT_EXPR. Must be COMPARISON_CLASS_P. */
118 enum tree_code comp_code;
120 /* Value being compared against. */
123 /* Expression to compare. */
126 /* Next node in the linked list. */
127 struct assert_locus_d *next;
130 typedef struct assert_locus_d *assert_locus_t;
132 /* If bit I is present, it means that SSA name N_i has a list of
133 assertions that should be inserted in the IL. */
134 static bitmap need_assert_for;
136 /* Array of locations lists where to insert assertions. ASSERTS_FOR[I]
137 holds a list of ASSERT_LOCUS_T nodes that describe where
138 ASSERT_EXPRs for SSA name N_I should be inserted. */
139 static assert_locus_t *asserts_for;
141 /* Value range array. After propagation, VR_VALUE[I] holds the range
142 of values that SSA name N_I may take. */
143 static unsigned num_vr_values;
144 static value_range_t **vr_value;
145 static bool values_propagated;
147 /* For a PHI node which sets SSA name N_I, VR_COUNTS[I] holds the
148 number of executable edges we saw the last time we visited the
150 static int *vr_phi_edge_counts;
157 static VEC (edge, heap) *to_remove_edges;
158 DEF_VEC_O(switch_update);
159 DEF_VEC_ALLOC_O(switch_update, heap);
160 static VEC (switch_update, heap) *to_update_switch_stmts;
163 /* Return the maximum value for TYPE. */
166 vrp_val_max (const_tree type)
168 if (!INTEGRAL_TYPE_P (type))
171 return TYPE_MAX_VALUE (type);
174 /* Return the minimum value for TYPE. */
177 vrp_val_min (const_tree type)
179 if (!INTEGRAL_TYPE_P (type))
182 return TYPE_MIN_VALUE (type);
185 /* Return whether VAL is equal to the maximum value of its type. This
186 will be true for a positive overflow infinity. We can't do a
187 simple equality comparison with TYPE_MAX_VALUE because C typedefs
188 and Ada subtypes can produce types whose TYPE_MAX_VALUE is not ==
189 to the integer constant with the same value in the type. */
192 vrp_val_is_max (const_tree val)
194 tree type_max = vrp_val_max (TREE_TYPE (val));
195 return (val == type_max
196 || (type_max != NULL_TREE
197 && operand_equal_p (val, type_max, 0)));
200 /* Return whether VAL is equal to the minimum value of its type. This
201 will be true for a negative overflow infinity. */
204 vrp_val_is_min (const_tree val)
206 tree type_min = vrp_val_min (TREE_TYPE (val));
207 return (val == type_min
208 || (type_min != NULL_TREE
209 && operand_equal_p (val, type_min, 0)));
213 /* Return whether TYPE should use an overflow infinity distinct from
214 TYPE_{MIN,MAX}_VALUE. We use an overflow infinity value to
215 represent a signed overflow during VRP computations. An infinity
216 is distinct from a half-range, which will go from some number to
217 TYPE_{MIN,MAX}_VALUE. */
220 needs_overflow_infinity (const_tree type)
222 return INTEGRAL_TYPE_P (type) && !TYPE_OVERFLOW_WRAPS (type);
225 /* Return whether TYPE can support our overflow infinity
226 representation: we use the TREE_OVERFLOW flag, which only exists
227 for constants. If TYPE doesn't support this, we don't optimize
228 cases which would require signed overflow--we drop them to
232 supports_overflow_infinity (const_tree type)
234 tree min = vrp_val_min (type), max = vrp_val_max (type);
235 #ifdef ENABLE_CHECKING
236 gcc_assert (needs_overflow_infinity (type));
238 return (min != NULL_TREE
239 && CONSTANT_CLASS_P (min)
241 && CONSTANT_CLASS_P (max));
244 /* VAL is the maximum or minimum value of a type. Return a
245 corresponding overflow infinity. */
248 make_overflow_infinity (tree val)
250 gcc_checking_assert (val != NULL_TREE && CONSTANT_CLASS_P (val));
251 val = copy_node (val);
252 TREE_OVERFLOW (val) = 1;
256 /* Return a negative overflow infinity for TYPE. */
259 negative_overflow_infinity (tree type)
261 gcc_checking_assert (supports_overflow_infinity (type));
262 return make_overflow_infinity (vrp_val_min (type));
265 /* Return a positive overflow infinity for TYPE. */
268 positive_overflow_infinity (tree type)
270 gcc_checking_assert (supports_overflow_infinity (type));
271 return make_overflow_infinity (vrp_val_max (type));
274 /* Return whether VAL is a negative overflow infinity. */
277 is_negative_overflow_infinity (const_tree val)
279 return (needs_overflow_infinity (TREE_TYPE (val))
280 && CONSTANT_CLASS_P (val)
281 && TREE_OVERFLOW (val)
282 && vrp_val_is_min (val));
285 /* Return whether VAL is a positive overflow infinity. */
288 is_positive_overflow_infinity (const_tree val)
290 return (needs_overflow_infinity (TREE_TYPE (val))
291 && CONSTANT_CLASS_P (val)
292 && TREE_OVERFLOW (val)
293 && vrp_val_is_max (val));
296 /* Return whether VAL is a positive or negative overflow infinity. */
299 is_overflow_infinity (const_tree val)
301 return (needs_overflow_infinity (TREE_TYPE (val))
302 && CONSTANT_CLASS_P (val)
303 && TREE_OVERFLOW (val)
304 && (vrp_val_is_min (val) || vrp_val_is_max (val)));
307 /* Return whether STMT has a constant rhs that is_overflow_infinity. */
310 stmt_overflow_infinity (gimple stmt)
312 if (is_gimple_assign (stmt)
313 && get_gimple_rhs_class (gimple_assign_rhs_code (stmt)) ==
315 return is_overflow_infinity (gimple_assign_rhs1 (stmt));
319 /* If VAL is now an overflow infinity, return VAL. Otherwise, return
320 the same value with TREE_OVERFLOW clear. This can be used to avoid
321 confusing a regular value with an overflow value. */
324 avoid_overflow_infinity (tree val)
326 if (!is_overflow_infinity (val))
329 if (vrp_val_is_max (val))
330 return vrp_val_max (TREE_TYPE (val));
333 gcc_checking_assert (vrp_val_is_min (val));
334 return vrp_val_min (TREE_TYPE (val));
339 /* Return true if ARG is marked with the nonnull attribute in the
340 current function signature. */
343 nonnull_arg_p (const_tree arg)
345 tree t, attrs, fntype;
346 unsigned HOST_WIDE_INT arg_num;
348 gcc_assert (TREE_CODE (arg) == PARM_DECL && POINTER_TYPE_P (TREE_TYPE (arg)));
350 /* The static chain decl is always non null. */
351 if (arg == cfun->static_chain_decl)
354 fntype = TREE_TYPE (current_function_decl);
355 attrs = lookup_attribute ("nonnull", TYPE_ATTRIBUTES (fntype));
357 /* If "nonnull" wasn't specified, we know nothing about the argument. */
358 if (attrs == NULL_TREE)
361 /* If "nonnull" applies to all the arguments, then ARG is non-null. */
362 if (TREE_VALUE (attrs) == NULL_TREE)
365 /* Get the position number for ARG in the function signature. */
366 for (arg_num = 1, t = DECL_ARGUMENTS (current_function_decl);
368 t = DECL_CHAIN (t), arg_num++)
374 gcc_assert (t == arg);
376 /* Now see if ARG_NUM is mentioned in the nonnull list. */
377 for (t = TREE_VALUE (attrs); t; t = TREE_CHAIN (t))
379 if (compare_tree_int (TREE_VALUE (t), arg_num) == 0)
387 /* Set value range VR to VR_VARYING. */
390 set_value_range_to_varying (value_range_t *vr)
392 vr->type = VR_VARYING;
393 vr->min = vr->max = NULL_TREE;
395 bitmap_clear (vr->equiv);
399 /* Set value range VR to {T, MIN, MAX, EQUIV}. */
402 set_value_range (value_range_t *vr, enum value_range_type t, tree min,
403 tree max, bitmap equiv)
405 #if defined ENABLE_CHECKING
406 /* Check the validity of the range. */
407 if (t == VR_RANGE || t == VR_ANTI_RANGE)
411 gcc_assert (min && max);
413 if (INTEGRAL_TYPE_P (TREE_TYPE (min)) && t == VR_ANTI_RANGE)
414 gcc_assert (!vrp_val_is_min (min) || !vrp_val_is_max (max));
416 cmp = compare_values (min, max);
417 gcc_assert (cmp == 0 || cmp == -1 || cmp == -2);
419 if (needs_overflow_infinity (TREE_TYPE (min)))
420 gcc_assert (!is_overflow_infinity (min)
421 || !is_overflow_infinity (max));
424 if (t == VR_UNDEFINED || t == VR_VARYING)
425 gcc_assert (min == NULL_TREE && max == NULL_TREE);
427 if (t == VR_UNDEFINED || t == VR_VARYING)
428 gcc_assert (equiv == NULL || bitmap_empty_p (equiv));
435 /* Since updating the equivalence set involves deep copying the
436 bitmaps, only do it if absolutely necessary. */
437 if (vr->equiv == NULL
439 vr->equiv = BITMAP_ALLOC (NULL);
441 if (equiv != vr->equiv)
443 if (equiv && !bitmap_empty_p (equiv))
444 bitmap_copy (vr->equiv, equiv);
446 bitmap_clear (vr->equiv);
451 /* Set value range VR to the canonical form of {T, MIN, MAX, EQUIV}.
452 This means adjusting T, MIN and MAX representing the case of a
453 wrapping range with MAX < MIN covering [MIN, type_max] U [type_min, MAX]
454 as anti-rage ~[MAX+1, MIN-1]. Likewise for wrapping anti-ranges.
455 In corner cases where MAX+1 or MIN-1 wraps this will fall back
457 This routine exists to ease canonicalization in the case where we
458 extract ranges from var + CST op limit. */
461 set_and_canonicalize_value_range (value_range_t *vr, enum value_range_type t,
462 tree min, tree max, bitmap equiv)
464 /* Nothing to canonicalize for symbolic or unknown or varying ranges. */
466 && t != VR_ANTI_RANGE)
467 || TREE_CODE (min) != INTEGER_CST
468 || TREE_CODE (max) != INTEGER_CST)
470 set_value_range (vr, t, min, max, equiv);
474 /* Wrong order for min and max, to swap them and the VR type we need
476 if (tree_int_cst_lt (max, min))
478 tree one = build_int_cst (TREE_TYPE (min), 1);
479 tree tmp = int_const_binop (PLUS_EXPR, max, one);
480 max = int_const_binop (MINUS_EXPR, min, one);
483 /* There's one corner case, if we had [C+1, C] before we now have
484 that again. But this represents an empty value range, so drop
485 to varying in this case. */
486 if (tree_int_cst_lt (max, min))
488 set_value_range_to_varying (vr);
492 t = t == VR_RANGE ? VR_ANTI_RANGE : VR_RANGE;
495 /* Anti-ranges that can be represented as ranges should be so. */
496 if (t == VR_ANTI_RANGE)
498 bool is_min = vrp_val_is_min (min);
499 bool is_max = vrp_val_is_max (max);
501 if (is_min && is_max)
503 /* We cannot deal with empty ranges, drop to varying. */
504 set_value_range_to_varying (vr);
508 /* As a special exception preserve non-null ranges. */
509 && !(TYPE_UNSIGNED (TREE_TYPE (min))
510 && integer_zerop (max)))
512 tree one = build_int_cst (TREE_TYPE (max), 1);
513 min = int_const_binop (PLUS_EXPR, max, one);
514 max = vrp_val_max (TREE_TYPE (max));
519 tree one = build_int_cst (TREE_TYPE (min), 1);
520 max = int_const_binop (MINUS_EXPR, min, one);
521 min = vrp_val_min (TREE_TYPE (min));
526 set_value_range (vr, t, min, max, equiv);
529 /* Copy value range FROM into value range TO. */
532 copy_value_range (value_range_t *to, value_range_t *from)
534 set_value_range (to, from->type, from->min, from->max, from->equiv);
537 /* Set value range VR to a single value. This function is only called
538 with values we get from statements, and exists to clear the
539 TREE_OVERFLOW flag so that we don't think we have an overflow
540 infinity when we shouldn't. */
543 set_value_range_to_value (value_range_t *vr, tree val, bitmap equiv)
545 gcc_assert (is_gimple_min_invariant (val));
546 val = avoid_overflow_infinity (val);
547 set_value_range (vr, VR_RANGE, val, val, equiv);
550 /* Set value range VR to a non-negative range of type TYPE.
551 OVERFLOW_INFINITY indicates whether to use an overflow infinity
552 rather than TYPE_MAX_VALUE; this should be true if we determine
553 that the range is nonnegative based on the assumption that signed
554 overflow does not occur. */
557 set_value_range_to_nonnegative (value_range_t *vr, tree type,
558 bool overflow_infinity)
562 if (overflow_infinity && !supports_overflow_infinity (type))
564 set_value_range_to_varying (vr);
568 zero = build_int_cst (type, 0);
569 set_value_range (vr, VR_RANGE, zero,
571 ? positive_overflow_infinity (type)
572 : TYPE_MAX_VALUE (type)),
576 /* Set value range VR to a non-NULL range of type TYPE. */
579 set_value_range_to_nonnull (value_range_t *vr, tree type)
581 tree zero = build_int_cst (type, 0);
582 set_value_range (vr, VR_ANTI_RANGE, zero, zero, vr->equiv);
586 /* Set value range VR to a NULL range of type TYPE. */
589 set_value_range_to_null (value_range_t *vr, tree type)
591 set_value_range_to_value (vr, build_int_cst (type, 0), vr->equiv);
595 /* Set value range VR to a range of a truthvalue of type TYPE. */
598 set_value_range_to_truthvalue (value_range_t *vr, tree type)
600 if (TYPE_PRECISION (type) == 1)
601 set_value_range_to_varying (vr);
603 set_value_range (vr, VR_RANGE,
604 build_int_cst (type, 0), build_int_cst (type, 1),
609 /* Set value range VR to VR_UNDEFINED. */
612 set_value_range_to_undefined (value_range_t *vr)
614 vr->type = VR_UNDEFINED;
615 vr->min = vr->max = NULL_TREE;
617 bitmap_clear (vr->equiv);
621 /* If abs (min) < abs (max), set VR to [-max, max], if
622 abs (min) >= abs (max), set VR to [-min, min]. */
625 abs_extent_range (value_range_t *vr, tree min, tree max)
629 gcc_assert (TREE_CODE (min) == INTEGER_CST);
630 gcc_assert (TREE_CODE (max) == INTEGER_CST);
631 gcc_assert (INTEGRAL_TYPE_P (TREE_TYPE (min)));
632 gcc_assert (!TYPE_UNSIGNED (TREE_TYPE (min)));
633 min = fold_unary (ABS_EXPR, TREE_TYPE (min), min);
634 max = fold_unary (ABS_EXPR, TREE_TYPE (max), max);
635 if (TREE_OVERFLOW (min) || TREE_OVERFLOW (max))
637 set_value_range_to_varying (vr);
640 cmp = compare_values (min, max);
642 min = fold_unary (NEGATE_EXPR, TREE_TYPE (min), max);
643 else if (cmp == 0 || cmp == 1)
646 min = fold_unary (NEGATE_EXPR, TREE_TYPE (min), min);
650 set_value_range_to_varying (vr);
653 set_and_canonicalize_value_range (vr, VR_RANGE, min, max, NULL);
657 /* Return value range information for VAR.
659 If we have no values ranges recorded (ie, VRP is not running), then
660 return NULL. Otherwise create an empty range if none existed for VAR. */
662 static value_range_t *
663 get_value_range (const_tree var)
665 static const struct value_range_d vr_const_varying
666 = { VR_VARYING, NULL_TREE, NULL_TREE, NULL };
669 unsigned ver = SSA_NAME_VERSION (var);
671 /* If we have no recorded ranges, then return NULL. */
675 /* If we query the range for a new SSA name return an unmodifiable VARYING.
676 We should get here at most from the substitute-and-fold stage which
677 will never try to change values. */
678 if (ver >= num_vr_values)
679 return CONST_CAST (value_range_t *, &vr_const_varying);
685 /* After propagation finished do not allocate new value-ranges. */
686 if (values_propagated)
687 return CONST_CAST (value_range_t *, &vr_const_varying);
689 /* Create a default value range. */
690 vr_value[ver] = vr = XCNEW (value_range_t);
692 /* Defer allocating the equivalence set. */
695 /* If VAR is a default definition of a parameter, the variable can
696 take any value in VAR's type. */
697 sym = SSA_NAME_VAR (var);
698 if (SSA_NAME_IS_DEFAULT_DEF (var))
700 if (TREE_CODE (sym) == PARM_DECL)
702 /* Try to use the "nonnull" attribute to create ~[0, 0]
703 anti-ranges for pointers. Note that this is only valid with
704 default definitions of PARM_DECLs. */
705 if (POINTER_TYPE_P (TREE_TYPE (sym))
706 && nonnull_arg_p (sym))
707 set_value_range_to_nonnull (vr, TREE_TYPE (sym));
709 set_value_range_to_varying (vr);
711 else if (TREE_CODE (sym) == RESULT_DECL
712 && DECL_BY_REFERENCE (sym))
713 set_value_range_to_nonnull (vr, TREE_TYPE (sym));
719 /* Return true, if VAL1 and VAL2 are equal values for VRP purposes. */
722 vrp_operand_equal_p (const_tree val1, const_tree val2)
726 if (!val1 || !val2 || !operand_equal_p (val1, val2, 0))
728 if (is_overflow_infinity (val1))
729 return is_overflow_infinity (val2);
733 /* Return true, if the bitmaps B1 and B2 are equal. */
736 vrp_bitmap_equal_p (const_bitmap b1, const_bitmap b2)
739 || ((!b1 || bitmap_empty_p (b1))
740 && (!b2 || bitmap_empty_p (b2)))
742 && bitmap_equal_p (b1, b2)));
745 /* Update the value range and equivalence set for variable VAR to
746 NEW_VR. Return true if NEW_VR is different from VAR's previous
749 NOTE: This function assumes that NEW_VR is a temporary value range
750 object created for the sole purpose of updating VAR's range. The
751 storage used by the equivalence set from NEW_VR will be freed by
752 this function. Do not call update_value_range when NEW_VR
753 is the range object associated with another SSA name. */
756 update_value_range (const_tree var, value_range_t *new_vr)
758 value_range_t *old_vr;
761 /* Update the value range, if necessary. */
762 old_vr = get_value_range (var);
763 is_new = old_vr->type != new_vr->type
764 || !vrp_operand_equal_p (old_vr->min, new_vr->min)
765 || !vrp_operand_equal_p (old_vr->max, new_vr->max)
766 || !vrp_bitmap_equal_p (old_vr->equiv, new_vr->equiv);
769 set_value_range (old_vr, new_vr->type, new_vr->min, new_vr->max,
772 BITMAP_FREE (new_vr->equiv);
778 /* Add VAR and VAR's equivalence set to EQUIV. This is the central
779 point where equivalence processing can be turned on/off. */
782 add_equivalence (bitmap *equiv, const_tree var)
784 unsigned ver = SSA_NAME_VERSION (var);
785 value_range_t *vr = vr_value[ver];
788 *equiv = BITMAP_ALLOC (NULL);
789 bitmap_set_bit (*equiv, ver);
791 bitmap_ior_into (*equiv, vr->equiv);
795 /* Return true if VR is ~[0, 0]. */
798 range_is_nonnull (value_range_t *vr)
800 return vr->type == VR_ANTI_RANGE
801 && integer_zerop (vr->min)
802 && integer_zerop (vr->max);
806 /* Return true if VR is [0, 0]. */
809 range_is_null (value_range_t *vr)
811 return vr->type == VR_RANGE
812 && integer_zerop (vr->min)
813 && integer_zerop (vr->max);
816 /* Return true if max and min of VR are INTEGER_CST. It's not necessary
820 range_int_cst_p (value_range_t *vr)
822 return (vr->type == VR_RANGE
823 && TREE_CODE (vr->max) == INTEGER_CST
824 && TREE_CODE (vr->min) == INTEGER_CST
825 && !TREE_OVERFLOW (vr->max)
826 && !TREE_OVERFLOW (vr->min));
829 /* Return true if VR is a INTEGER_CST singleton. */
832 range_int_cst_singleton_p (value_range_t *vr)
834 return (range_int_cst_p (vr)
835 && tree_int_cst_equal (vr->min, vr->max));
838 /* Return true if value range VR involves at least one symbol. */
841 symbolic_range_p (value_range_t *vr)
843 return (!is_gimple_min_invariant (vr->min)
844 || !is_gimple_min_invariant (vr->max));
847 /* Return true if value range VR uses an overflow infinity. */
850 overflow_infinity_range_p (value_range_t *vr)
852 return (vr->type == VR_RANGE
853 && (is_overflow_infinity (vr->min)
854 || is_overflow_infinity (vr->max)));
857 /* Return false if we can not make a valid comparison based on VR;
858 this will be the case if it uses an overflow infinity and overflow
859 is not undefined (i.e., -fno-strict-overflow is in effect).
860 Otherwise return true, and set *STRICT_OVERFLOW_P to true if VR
861 uses an overflow infinity. */
864 usable_range_p (value_range_t *vr, bool *strict_overflow_p)
866 gcc_assert (vr->type == VR_RANGE);
867 if (is_overflow_infinity (vr->min))
869 *strict_overflow_p = true;
870 if (!TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (vr->min)))
873 if (is_overflow_infinity (vr->max))
875 *strict_overflow_p = true;
876 if (!TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (vr->max)))
883 /* Return true if the result of assignment STMT is know to be non-negative.
884 If the return value is based on the assumption that signed overflow is
885 undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't change
886 *STRICT_OVERFLOW_P.*/
889 gimple_assign_nonnegative_warnv_p (gimple stmt, bool *strict_overflow_p)
891 enum tree_code code = gimple_assign_rhs_code (stmt);
892 switch (get_gimple_rhs_class (code))
894 case GIMPLE_UNARY_RHS:
895 return tree_unary_nonnegative_warnv_p (gimple_assign_rhs_code (stmt),
896 gimple_expr_type (stmt),
897 gimple_assign_rhs1 (stmt),
899 case GIMPLE_BINARY_RHS:
900 return tree_binary_nonnegative_warnv_p (gimple_assign_rhs_code (stmt),
901 gimple_expr_type (stmt),
902 gimple_assign_rhs1 (stmt),
903 gimple_assign_rhs2 (stmt),
905 case GIMPLE_TERNARY_RHS:
907 case GIMPLE_SINGLE_RHS:
908 return tree_single_nonnegative_warnv_p (gimple_assign_rhs1 (stmt),
910 case GIMPLE_INVALID_RHS:
917 /* Return true if return value of call STMT is know to be non-negative.
918 If the return value is based on the assumption that signed overflow is
919 undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't change
920 *STRICT_OVERFLOW_P.*/
923 gimple_call_nonnegative_warnv_p (gimple stmt, bool *strict_overflow_p)
925 tree arg0 = gimple_call_num_args (stmt) > 0 ?
926 gimple_call_arg (stmt, 0) : NULL_TREE;
927 tree arg1 = gimple_call_num_args (stmt) > 1 ?
928 gimple_call_arg (stmt, 1) : NULL_TREE;
930 return tree_call_nonnegative_warnv_p (gimple_expr_type (stmt),
931 gimple_call_fndecl (stmt),
937 /* Return true if STMT is know to to compute a non-negative value.
938 If the return value is based on the assumption that signed overflow is
939 undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't change
940 *STRICT_OVERFLOW_P.*/
943 gimple_stmt_nonnegative_warnv_p (gimple stmt, bool *strict_overflow_p)
945 switch (gimple_code (stmt))
948 return gimple_assign_nonnegative_warnv_p (stmt, strict_overflow_p);
950 return gimple_call_nonnegative_warnv_p (stmt, strict_overflow_p);
956 /* Return true if the result of assignment STMT is know to be non-zero.
957 If the return value is based on the assumption that signed overflow is
958 undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't change
959 *STRICT_OVERFLOW_P.*/
962 gimple_assign_nonzero_warnv_p (gimple stmt, bool *strict_overflow_p)
964 enum tree_code code = gimple_assign_rhs_code (stmt);
965 switch (get_gimple_rhs_class (code))
967 case GIMPLE_UNARY_RHS:
968 return tree_unary_nonzero_warnv_p (gimple_assign_rhs_code (stmt),
969 gimple_expr_type (stmt),
970 gimple_assign_rhs1 (stmt),
972 case GIMPLE_BINARY_RHS:
973 return tree_binary_nonzero_warnv_p (gimple_assign_rhs_code (stmt),
974 gimple_expr_type (stmt),
975 gimple_assign_rhs1 (stmt),
976 gimple_assign_rhs2 (stmt),
978 case GIMPLE_TERNARY_RHS:
980 case GIMPLE_SINGLE_RHS:
981 return tree_single_nonzero_warnv_p (gimple_assign_rhs1 (stmt),
983 case GIMPLE_INVALID_RHS:
990 /* Return true if STMT is know to to compute a non-zero value.
991 If the return value is based on the assumption that signed overflow is
992 undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't change
993 *STRICT_OVERFLOW_P.*/
996 gimple_stmt_nonzero_warnv_p (gimple stmt, bool *strict_overflow_p)
998 switch (gimple_code (stmt))
1001 return gimple_assign_nonzero_warnv_p (stmt, strict_overflow_p);
1003 return gimple_alloca_call_p (stmt);
1009 /* Like tree_expr_nonzero_warnv_p, but this function uses value ranges
1013 vrp_stmt_computes_nonzero (gimple stmt, bool *strict_overflow_p)
1015 if (gimple_stmt_nonzero_warnv_p (stmt, strict_overflow_p))
1018 /* If we have an expression of the form &X->a, then the expression
1019 is nonnull if X is nonnull. */
1020 if (is_gimple_assign (stmt)
1021 && gimple_assign_rhs_code (stmt) == ADDR_EXPR)
1023 tree expr = gimple_assign_rhs1 (stmt);
1024 tree base = get_base_address (TREE_OPERAND (expr, 0));
1026 if (base != NULL_TREE
1027 && TREE_CODE (base) == MEM_REF
1028 && TREE_CODE (TREE_OPERAND (base, 0)) == SSA_NAME)
1030 value_range_t *vr = get_value_range (TREE_OPERAND (base, 0));
1031 if (range_is_nonnull (vr))
1039 /* Returns true if EXPR is a valid value (as expected by compare_values) --
1040 a gimple invariant, or SSA_NAME +- CST. */
1043 valid_value_p (tree expr)
1045 if (TREE_CODE (expr) == SSA_NAME)
1048 if (TREE_CODE (expr) == PLUS_EXPR
1049 || TREE_CODE (expr) == MINUS_EXPR)
1050 return (TREE_CODE (TREE_OPERAND (expr, 0)) == SSA_NAME
1051 && TREE_CODE (TREE_OPERAND (expr, 1)) == INTEGER_CST);
1053 return is_gimple_min_invariant (expr);
1059 -2 if those are incomparable. */
1061 operand_less_p (tree val, tree val2)
1063 /* LT is folded faster than GE and others. Inline the common case. */
1064 if (TREE_CODE (val) == INTEGER_CST && TREE_CODE (val2) == INTEGER_CST)
1066 if (TYPE_UNSIGNED (TREE_TYPE (val)))
1067 return INT_CST_LT_UNSIGNED (val, val2);
1070 if (INT_CST_LT (val, val2))
1078 fold_defer_overflow_warnings ();
1080 tcmp = fold_binary_to_constant (LT_EXPR, boolean_type_node, val, val2);
1082 fold_undefer_and_ignore_overflow_warnings ();
1085 || TREE_CODE (tcmp) != INTEGER_CST)
1088 if (!integer_zerop (tcmp))
1092 /* val >= val2, not considering overflow infinity. */
1093 if (is_negative_overflow_infinity (val))
1094 return is_negative_overflow_infinity (val2) ? 0 : 1;
1095 else if (is_positive_overflow_infinity (val2))
1096 return is_positive_overflow_infinity (val) ? 0 : 1;
1101 /* Compare two values VAL1 and VAL2. Return
1103 -2 if VAL1 and VAL2 cannot be compared at compile-time,
1106 +1 if VAL1 > VAL2, and
1109 This is similar to tree_int_cst_compare but supports pointer values
1110 and values that cannot be compared at compile time.
1112 If STRICT_OVERFLOW_P is not NULL, then set *STRICT_OVERFLOW_P to
1113 true if the return value is only valid if we assume that signed
1114 overflow is undefined. */
1117 compare_values_warnv (tree val1, tree val2, bool *strict_overflow_p)
1122 /* Below we rely on the fact that VAL1 and VAL2 are both pointers or
1124 gcc_assert (POINTER_TYPE_P (TREE_TYPE (val1))
1125 == POINTER_TYPE_P (TREE_TYPE (val2)));
1126 /* Convert the two values into the same type. This is needed because
1127 sizetype causes sign extension even for unsigned types. */
1128 val2 = fold_convert (TREE_TYPE (val1), val2);
1129 STRIP_USELESS_TYPE_CONVERSION (val2);
1131 if ((TREE_CODE (val1) == SSA_NAME
1132 || TREE_CODE (val1) == PLUS_EXPR
1133 || TREE_CODE (val1) == MINUS_EXPR)
1134 && (TREE_CODE (val2) == SSA_NAME
1135 || TREE_CODE (val2) == PLUS_EXPR
1136 || TREE_CODE (val2) == MINUS_EXPR))
1138 tree n1, c1, n2, c2;
1139 enum tree_code code1, code2;
1141 /* If VAL1 and VAL2 are of the form 'NAME [+-] CST' or 'NAME',
1142 return -1 or +1 accordingly. If VAL1 and VAL2 don't use the
1143 same name, return -2. */
1144 if (TREE_CODE (val1) == SSA_NAME)
1152 code1 = TREE_CODE (val1);
1153 n1 = TREE_OPERAND (val1, 0);
1154 c1 = TREE_OPERAND (val1, 1);
1155 if (tree_int_cst_sgn (c1) == -1)
1157 if (is_negative_overflow_infinity (c1))
1159 c1 = fold_unary_to_constant (NEGATE_EXPR, TREE_TYPE (c1), c1);
1162 code1 = code1 == MINUS_EXPR ? PLUS_EXPR : MINUS_EXPR;
1166 if (TREE_CODE (val2) == SSA_NAME)
1174 code2 = TREE_CODE (val2);
1175 n2 = TREE_OPERAND (val2, 0);
1176 c2 = TREE_OPERAND (val2, 1);
1177 if (tree_int_cst_sgn (c2) == -1)
1179 if (is_negative_overflow_infinity (c2))
1181 c2 = fold_unary_to_constant (NEGATE_EXPR, TREE_TYPE (c2), c2);
1184 code2 = code2 == MINUS_EXPR ? PLUS_EXPR : MINUS_EXPR;
1188 /* Both values must use the same name. */
1192 if (code1 == SSA_NAME
1193 && code2 == SSA_NAME)
1197 /* If overflow is defined we cannot simplify more. */
1198 if (!TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (val1)))
1201 if (strict_overflow_p != NULL
1202 && (code1 == SSA_NAME || !TREE_NO_WARNING (val1))
1203 && (code2 == SSA_NAME || !TREE_NO_WARNING (val2)))
1204 *strict_overflow_p = true;
1206 if (code1 == SSA_NAME)
1208 if (code2 == PLUS_EXPR)
1209 /* NAME < NAME + CST */
1211 else if (code2 == MINUS_EXPR)
1212 /* NAME > NAME - CST */
1215 else if (code1 == PLUS_EXPR)
1217 if (code2 == SSA_NAME)
1218 /* NAME + CST > NAME */
1220 else if (code2 == PLUS_EXPR)
1221 /* NAME + CST1 > NAME + CST2, if CST1 > CST2 */
1222 return compare_values_warnv (c1, c2, strict_overflow_p);
1223 else if (code2 == MINUS_EXPR)
1224 /* NAME + CST1 > NAME - CST2 */
1227 else if (code1 == MINUS_EXPR)
1229 if (code2 == SSA_NAME)
1230 /* NAME - CST < NAME */
1232 else if (code2 == PLUS_EXPR)
1233 /* NAME - CST1 < NAME + CST2 */
1235 else if (code2 == MINUS_EXPR)
1236 /* NAME - CST1 > NAME - CST2, if CST1 < CST2. Notice that
1237 C1 and C2 are swapped in the call to compare_values. */
1238 return compare_values_warnv (c2, c1, strict_overflow_p);
1244 /* We cannot compare non-constants. */
1245 if (!is_gimple_min_invariant (val1) || !is_gimple_min_invariant (val2))
1248 if (!POINTER_TYPE_P (TREE_TYPE (val1)))
1250 /* We cannot compare overflowed values, except for overflow
1252 if (TREE_OVERFLOW (val1) || TREE_OVERFLOW (val2))
1254 if (strict_overflow_p != NULL)
1255 *strict_overflow_p = true;
1256 if (is_negative_overflow_infinity (val1))
1257 return is_negative_overflow_infinity (val2) ? 0 : -1;
1258 else if (is_negative_overflow_infinity (val2))
1260 else if (is_positive_overflow_infinity (val1))
1261 return is_positive_overflow_infinity (val2) ? 0 : 1;
1262 else if (is_positive_overflow_infinity (val2))
1267 return tree_int_cst_compare (val1, val2);
1273 /* First see if VAL1 and VAL2 are not the same. */
1274 if (val1 == val2 || operand_equal_p (val1, val2, 0))
1277 /* If VAL1 is a lower address than VAL2, return -1. */
1278 if (operand_less_p (val1, val2) == 1)
1281 /* If VAL1 is a higher address than VAL2, return +1. */
1282 if (operand_less_p (val2, val1) == 1)
1285 /* If VAL1 is different than VAL2, return +2.
1286 For integer constants we either have already returned -1 or 1
1287 or they are equivalent. We still might succeed in proving
1288 something about non-trivial operands. */
1289 if (TREE_CODE (val1) != INTEGER_CST
1290 || TREE_CODE (val2) != INTEGER_CST)
1292 t = fold_binary_to_constant (NE_EXPR, boolean_type_node, val1, val2);
1293 if (t && integer_onep (t))
1301 /* Compare values like compare_values_warnv, but treat comparisons of
1302 nonconstants which rely on undefined overflow as incomparable. */
1305 compare_values (tree val1, tree val2)
1311 ret = compare_values_warnv (val1, val2, &sop);
1313 && (!is_gimple_min_invariant (val1) || !is_gimple_min_invariant (val2)))
1319 /* Return 1 if VAL is inside value range VR (VR->MIN <= VAL <= VR->MAX),
1320 0 if VAL is not inside VR,
1321 -2 if we cannot tell either way.
1323 FIXME, the current semantics of this functions are a bit quirky
1324 when taken in the context of VRP. In here we do not care
1325 about VR's type. If VR is the anti-range ~[3, 5] the call
1326 value_inside_range (4, VR) will return 1.
1328 This is counter-intuitive in a strict sense, but the callers
1329 currently expect this. They are calling the function
1330 merely to determine whether VR->MIN <= VAL <= VR->MAX. The
1331 callers are applying the VR_RANGE/VR_ANTI_RANGE semantics
1334 This also applies to value_ranges_intersect_p and
1335 range_includes_zero_p. The semantics of VR_RANGE and
1336 VR_ANTI_RANGE should be encoded here, but that also means
1337 adapting the users of these functions to the new semantics.
1339 Benchmark compile/20001226-1.c compilation time after changing this
1343 value_inside_range (tree val, value_range_t * vr)
1347 cmp1 = operand_less_p (val, vr->min);
1353 cmp2 = operand_less_p (vr->max, val);
1361 /* Return true if value ranges VR0 and VR1 have a non-empty
1364 Benchmark compile/20001226-1.c compilation time after changing this
1369 value_ranges_intersect_p (value_range_t *vr0, value_range_t *vr1)
1371 /* The value ranges do not intersect if the maximum of the first range is
1372 less than the minimum of the second range or vice versa.
1373 When those relations are unknown, we can't do any better. */
1374 if (operand_less_p (vr0->max, vr1->min) != 0)
1376 if (operand_less_p (vr1->max, vr0->min) != 0)
1382 /* Return true if VR includes the value zero, false otherwise. FIXME,
1383 currently this will return false for an anti-range like ~[-4, 3].
1384 This will be wrong when the semantics of value_inside_range are
1385 modified (currently the users of this function expect these
1389 range_includes_zero_p (value_range_t *vr)
1393 gcc_assert (vr->type != VR_UNDEFINED
1394 && vr->type != VR_VARYING
1395 && !symbolic_range_p (vr));
1397 zero = build_int_cst (TREE_TYPE (vr->min), 0);
1398 return (value_inside_range (zero, vr) == 1);
1401 /* Return true if *VR is know to only contain nonnegative values. */
1404 value_range_nonnegative_p (value_range_t *vr)
1406 /* Testing for VR_ANTI_RANGE is not useful here as any anti-range
1407 which would return a useful value should be encoded as a
1409 if (vr->type == VR_RANGE)
1411 int result = compare_values (vr->min, integer_zero_node);
1412 return (result == 0 || result == 1);
1418 /* Return true if T, an SSA_NAME, is known to be nonnegative. Return
1419 false otherwise or if no value range information is available. */
1422 ssa_name_nonnegative_p (const_tree t)
1424 value_range_t *vr = get_value_range (t);
1426 if (INTEGRAL_TYPE_P (t)
1427 && TYPE_UNSIGNED (t))
1433 return value_range_nonnegative_p (vr);
1436 /* If *VR has a value rante that is a single constant value return that,
1437 otherwise return NULL_TREE. */
1440 value_range_constant_singleton (value_range_t *vr)
1442 if (vr->type == VR_RANGE
1443 && operand_equal_p (vr->min, vr->max, 0)
1444 && is_gimple_min_invariant (vr->min))
1450 /* If OP has a value range with a single constant value return that,
1451 otherwise return NULL_TREE. This returns OP itself if OP is a
1455 op_with_constant_singleton_value_range (tree op)
1457 if (is_gimple_min_invariant (op))
1460 if (TREE_CODE (op) != SSA_NAME)
1463 return value_range_constant_singleton (get_value_range (op));
1466 /* Return true if op is in a boolean [0, 1] value-range. */
1469 op_with_boolean_value_range_p (tree op)
1473 if (TYPE_PRECISION (TREE_TYPE (op)) == 1)
1476 if (integer_zerop (op)
1477 || integer_onep (op))
1480 if (TREE_CODE (op) != SSA_NAME)
1483 vr = get_value_range (op);
1484 return (vr->type == VR_RANGE
1485 && integer_zerop (vr->min)
1486 && integer_onep (vr->max));
1489 /* Extract value range information from an ASSERT_EXPR EXPR and store
1493 extract_range_from_assert (value_range_t *vr_p, tree expr)
1495 tree var, cond, limit, min, max, type;
1496 value_range_t *var_vr, *limit_vr;
1497 enum tree_code cond_code;
1499 var = ASSERT_EXPR_VAR (expr);
1500 cond = ASSERT_EXPR_COND (expr);
1502 gcc_assert (COMPARISON_CLASS_P (cond));
1504 /* Find VAR in the ASSERT_EXPR conditional. */
1505 if (var == TREE_OPERAND (cond, 0)
1506 || TREE_CODE (TREE_OPERAND (cond, 0)) == PLUS_EXPR
1507 || TREE_CODE (TREE_OPERAND (cond, 0)) == NOP_EXPR)
1509 /* If the predicate is of the form VAR COMP LIMIT, then we just
1510 take LIMIT from the RHS and use the same comparison code. */
1511 cond_code = TREE_CODE (cond);
1512 limit = TREE_OPERAND (cond, 1);
1513 cond = TREE_OPERAND (cond, 0);
1517 /* If the predicate is of the form LIMIT COMP VAR, then we need
1518 to flip around the comparison code to create the proper range
1520 cond_code = swap_tree_comparison (TREE_CODE (cond));
1521 limit = TREE_OPERAND (cond, 0);
1522 cond = TREE_OPERAND (cond, 1);
1525 limit = avoid_overflow_infinity (limit);
1527 type = TREE_TYPE (var);
1528 gcc_assert (limit != var);
1530 /* For pointer arithmetic, we only keep track of pointer equality
1532 if (POINTER_TYPE_P (type) && cond_code != NE_EXPR && cond_code != EQ_EXPR)
1534 set_value_range_to_varying (vr_p);
1538 /* If LIMIT is another SSA name and LIMIT has a range of its own,
1539 try to use LIMIT's range to avoid creating symbolic ranges
1541 limit_vr = (TREE_CODE (limit) == SSA_NAME) ? get_value_range (limit) : NULL;
1543 /* LIMIT's range is only interesting if it has any useful information. */
1545 && (limit_vr->type == VR_UNDEFINED
1546 || limit_vr->type == VR_VARYING
1547 || symbolic_range_p (limit_vr)))
1550 /* Initially, the new range has the same set of equivalences of
1551 VAR's range. This will be revised before returning the final
1552 value. Since assertions may be chained via mutually exclusive
1553 predicates, we will need to trim the set of equivalences before
1555 gcc_assert (vr_p->equiv == NULL);
1556 add_equivalence (&vr_p->equiv, var);
1558 /* Extract a new range based on the asserted comparison for VAR and
1559 LIMIT's value range. Notice that if LIMIT has an anti-range, we
1560 will only use it for equality comparisons (EQ_EXPR). For any
1561 other kind of assertion, we cannot derive a range from LIMIT's
1562 anti-range that can be used to describe the new range. For
1563 instance, ASSERT_EXPR <x_2, x_2 <= b_4>. If b_4 is ~[2, 10],
1564 then b_4 takes on the ranges [-INF, 1] and [11, +INF]. There is
1565 no single range for x_2 that could describe LE_EXPR, so we might
1566 as well build the range [b_4, +INF] for it.
1567 One special case we handle is extracting a range from a
1568 range test encoded as (unsigned)var + CST <= limit. */
1569 if (TREE_CODE (cond) == NOP_EXPR
1570 || TREE_CODE (cond) == PLUS_EXPR)
1572 if (TREE_CODE (cond) == PLUS_EXPR)
1574 min = fold_build1 (NEGATE_EXPR, TREE_TYPE (TREE_OPERAND (cond, 1)),
1575 TREE_OPERAND (cond, 1));
1576 max = int_const_binop (PLUS_EXPR, limit, min);
1577 cond = TREE_OPERAND (cond, 0);
1581 min = build_int_cst (TREE_TYPE (var), 0);
1585 /* Make sure to not set TREE_OVERFLOW on the final type
1586 conversion. We are willingly interpreting large positive
1587 unsigned values as negative singed values here. */
1588 min = force_fit_type_double (TREE_TYPE (var), tree_to_double_int (min),
1590 max = force_fit_type_double (TREE_TYPE (var), tree_to_double_int (max),
1593 /* We can transform a max, min range to an anti-range or
1594 vice-versa. Use set_and_canonicalize_value_range which does
1596 if (cond_code == LE_EXPR)
1597 set_and_canonicalize_value_range (vr_p, VR_RANGE,
1598 min, max, vr_p->equiv);
1599 else if (cond_code == GT_EXPR)
1600 set_and_canonicalize_value_range (vr_p, VR_ANTI_RANGE,
1601 min, max, vr_p->equiv);
1605 else if (cond_code == EQ_EXPR)
1607 enum value_range_type range_type;
1611 range_type = limit_vr->type;
1612 min = limit_vr->min;
1613 max = limit_vr->max;
1617 range_type = VR_RANGE;
1622 set_value_range (vr_p, range_type, min, max, vr_p->equiv);
1624 /* When asserting the equality VAR == LIMIT and LIMIT is another
1625 SSA name, the new range will also inherit the equivalence set
1627 if (TREE_CODE (limit) == SSA_NAME)
1628 add_equivalence (&vr_p->equiv, limit);
1630 else if (cond_code == NE_EXPR)
1632 /* As described above, when LIMIT's range is an anti-range and
1633 this assertion is an inequality (NE_EXPR), then we cannot
1634 derive anything from the anti-range. For instance, if
1635 LIMIT's range was ~[0, 0], the assertion 'VAR != LIMIT' does
1636 not imply that VAR's range is [0, 0]. So, in the case of
1637 anti-ranges, we just assert the inequality using LIMIT and
1640 If LIMIT_VR is a range, we can only use it to build a new
1641 anti-range if LIMIT_VR is a single-valued range. For
1642 instance, if LIMIT_VR is [0, 1], the predicate
1643 VAR != [0, 1] does not mean that VAR's range is ~[0, 1].
1644 Rather, it means that for value 0 VAR should be ~[0, 0]
1645 and for value 1, VAR should be ~[1, 1]. We cannot
1646 represent these ranges.
1648 The only situation in which we can build a valid
1649 anti-range is when LIMIT_VR is a single-valued range
1650 (i.e., LIMIT_VR->MIN == LIMIT_VR->MAX). In that case,
1651 build the anti-range ~[LIMIT_VR->MIN, LIMIT_VR->MAX]. */
1653 && limit_vr->type == VR_RANGE
1654 && compare_values (limit_vr->min, limit_vr->max) == 0)
1656 min = limit_vr->min;
1657 max = limit_vr->max;
1661 /* In any other case, we cannot use LIMIT's range to build a
1662 valid anti-range. */
1666 /* If MIN and MAX cover the whole range for their type, then
1667 just use the original LIMIT. */
1668 if (INTEGRAL_TYPE_P (type)
1669 && vrp_val_is_min (min)
1670 && vrp_val_is_max (max))
1673 set_value_range (vr_p, VR_ANTI_RANGE, min, max, vr_p->equiv);
1675 else if (cond_code == LE_EXPR || cond_code == LT_EXPR)
1677 min = TYPE_MIN_VALUE (type);
1679 if (limit_vr == NULL || limit_vr->type == VR_ANTI_RANGE)
1683 /* If LIMIT_VR is of the form [N1, N2], we need to build the
1684 range [MIN, N2] for LE_EXPR and [MIN, N2 - 1] for
1686 max = limit_vr->max;
1689 /* If the maximum value forces us to be out of bounds, simply punt.
1690 It would be pointless to try and do anything more since this
1691 all should be optimized away above us. */
1692 if ((cond_code == LT_EXPR
1693 && compare_values (max, min) == 0)
1694 || (CONSTANT_CLASS_P (max) && TREE_OVERFLOW (max)))
1695 set_value_range_to_varying (vr_p);
1698 /* For LT_EXPR, we create the range [MIN, MAX - 1]. */
1699 if (cond_code == LT_EXPR)
1701 if (TYPE_PRECISION (TREE_TYPE (max)) == 1
1702 && !TYPE_UNSIGNED (TREE_TYPE (max)))
1703 max = fold_build2 (PLUS_EXPR, TREE_TYPE (max), max,
1704 build_int_cst (TREE_TYPE (max), -1));
1706 max = fold_build2 (MINUS_EXPR, TREE_TYPE (max), max,
1707 build_int_cst (TREE_TYPE (max), 1));
1709 TREE_NO_WARNING (max) = 1;
1712 set_value_range (vr_p, VR_RANGE, min, max, vr_p->equiv);
1715 else if (cond_code == GE_EXPR || cond_code == GT_EXPR)
1717 max = TYPE_MAX_VALUE (type);
1719 if (limit_vr == NULL || limit_vr->type == VR_ANTI_RANGE)
1723 /* If LIMIT_VR is of the form [N1, N2], we need to build the
1724 range [N1, MAX] for GE_EXPR and [N1 + 1, MAX] for
1726 min = limit_vr->min;
1729 /* If the minimum value forces us to be out of bounds, simply punt.
1730 It would be pointless to try and do anything more since this
1731 all should be optimized away above us. */
1732 if ((cond_code == GT_EXPR
1733 && compare_values (min, max) == 0)
1734 || (CONSTANT_CLASS_P (min) && TREE_OVERFLOW (min)))
1735 set_value_range_to_varying (vr_p);
1738 /* For GT_EXPR, we create the range [MIN + 1, MAX]. */
1739 if (cond_code == GT_EXPR)
1741 if (TYPE_PRECISION (TREE_TYPE (min)) == 1
1742 && !TYPE_UNSIGNED (TREE_TYPE (min)))
1743 min = fold_build2 (MINUS_EXPR, TREE_TYPE (min), min,
1744 build_int_cst (TREE_TYPE (min), -1));
1746 min = fold_build2 (PLUS_EXPR, TREE_TYPE (min), min,
1747 build_int_cst (TREE_TYPE (min), 1));
1749 TREE_NO_WARNING (min) = 1;
1752 set_value_range (vr_p, VR_RANGE, min, max, vr_p->equiv);
1758 /* If VAR already had a known range, it may happen that the new
1759 range we have computed and VAR's range are not compatible. For
1763 p_6 = ASSERT_EXPR <p_5, p_5 == NULL>;
1765 p_8 = ASSERT_EXPR <p_6, p_6 != NULL>;
1767 While the above comes from a faulty program, it will cause an ICE
1768 later because p_8 and p_6 will have incompatible ranges and at
1769 the same time will be considered equivalent. A similar situation
1773 i_6 = ASSERT_EXPR <i_5, i_5 > 10>;
1775 i_7 = ASSERT_EXPR <i_6, i_6 < 5>;
1777 Again i_6 and i_7 will have incompatible ranges. It would be
1778 pointless to try and do anything with i_7's range because
1779 anything dominated by 'if (i_5 < 5)' will be optimized away.
1780 Note, due to the wa in which simulation proceeds, the statement
1781 i_7 = ASSERT_EXPR <...> we would never be visited because the
1782 conditional 'if (i_5 < 5)' always evaluates to false. However,
1783 this extra check does not hurt and may protect against future
1784 changes to VRP that may get into a situation similar to the
1785 NULL pointer dereference example.
1787 Note that these compatibility tests are only needed when dealing
1788 with ranges or a mix of range and anti-range. If VAR_VR and VR_P
1789 are both anti-ranges, they will always be compatible, because two
1790 anti-ranges will always have a non-empty intersection. */
1792 var_vr = get_value_range (var);
1794 /* We may need to make adjustments when VR_P and VAR_VR are numeric
1795 ranges or anti-ranges. */
1796 if (vr_p->type == VR_VARYING
1797 || vr_p->type == VR_UNDEFINED
1798 || var_vr->type == VR_VARYING
1799 || var_vr->type == VR_UNDEFINED
1800 || symbolic_range_p (vr_p)
1801 || symbolic_range_p (var_vr))
1804 if (var_vr->type == VR_RANGE && vr_p->type == VR_RANGE)
1806 /* If the two ranges have a non-empty intersection, we can
1807 refine the resulting range. Since the assert expression
1808 creates an equivalency and at the same time it asserts a
1809 predicate, we can take the intersection of the two ranges to
1810 get better precision. */
1811 if (value_ranges_intersect_p (var_vr, vr_p))
1813 /* Use the larger of the two minimums. */
1814 if (compare_values (vr_p->min, var_vr->min) == -1)
1819 /* Use the smaller of the two maximums. */
1820 if (compare_values (vr_p->max, var_vr->max) == 1)
1825 set_value_range (vr_p, vr_p->type, min, max, vr_p->equiv);
1829 /* The two ranges do not intersect, set the new range to
1830 VARYING, because we will not be able to do anything
1831 meaningful with it. */
1832 set_value_range_to_varying (vr_p);
1835 else if ((var_vr->type == VR_RANGE && vr_p->type == VR_ANTI_RANGE)
1836 || (var_vr->type == VR_ANTI_RANGE && vr_p->type == VR_RANGE))
1838 /* A range and an anti-range will cancel each other only if
1839 their ends are the same. For instance, in the example above,
1840 p_8's range ~[0, 0] and p_6's range [0, 0] are incompatible,
1841 so VR_P should be set to VR_VARYING. */
1842 if (compare_values (var_vr->min, vr_p->min) == 0
1843 && compare_values (var_vr->max, vr_p->max) == 0)
1844 set_value_range_to_varying (vr_p);
1847 tree min, max, anti_min, anti_max, real_min, real_max;
1850 /* We want to compute the logical AND of the two ranges;
1851 there are three cases to consider.
1854 1. The VR_ANTI_RANGE range is completely within the
1855 VR_RANGE and the endpoints of the ranges are
1856 different. In that case the resulting range
1857 should be whichever range is more precise.
1858 Typically that will be the VR_RANGE.
1860 2. The VR_ANTI_RANGE is completely disjoint from
1861 the VR_RANGE. In this case the resulting range
1862 should be the VR_RANGE.
1864 3. There is some overlap between the VR_ANTI_RANGE
1867 3a. If the high limit of the VR_ANTI_RANGE resides
1868 within the VR_RANGE, then the result is a new
1869 VR_RANGE starting at the high limit of the
1870 VR_ANTI_RANGE + 1 and extending to the
1871 high limit of the original VR_RANGE.
1873 3b. If the low limit of the VR_ANTI_RANGE resides
1874 within the VR_RANGE, then the result is a new
1875 VR_RANGE starting at the low limit of the original
1876 VR_RANGE and extending to the low limit of the
1877 VR_ANTI_RANGE - 1. */
1878 if (vr_p->type == VR_ANTI_RANGE)
1880 anti_min = vr_p->min;
1881 anti_max = vr_p->max;
1882 real_min = var_vr->min;
1883 real_max = var_vr->max;
1887 anti_min = var_vr->min;
1888 anti_max = var_vr->max;
1889 real_min = vr_p->min;
1890 real_max = vr_p->max;
1894 /* Case 1, VR_ANTI_RANGE completely within VR_RANGE,
1895 not including any endpoints. */
1896 if (compare_values (anti_max, real_max) == -1
1897 && compare_values (anti_min, real_min) == 1)
1899 /* If the range is covering the whole valid range of
1900 the type keep the anti-range. */
1901 if (!vrp_val_is_min (real_min)
1902 || !vrp_val_is_max (real_max))
1903 set_value_range (vr_p, VR_RANGE, real_min,
1904 real_max, vr_p->equiv);
1906 /* Case 2, VR_ANTI_RANGE completely disjoint from
1908 else if (compare_values (anti_min, real_max) == 1
1909 || compare_values (anti_max, real_min) == -1)
1911 set_value_range (vr_p, VR_RANGE, real_min,
1912 real_max, vr_p->equiv);
1914 /* Case 3a, the anti-range extends into the low
1915 part of the real range. Thus creating a new
1916 low for the real range. */
1917 else if (((cmp = compare_values (anti_max, real_min)) == 1
1919 && compare_values (anti_max, real_max) == -1)
1921 gcc_assert (!is_positive_overflow_infinity (anti_max));
1922 if (needs_overflow_infinity (TREE_TYPE (anti_max))
1923 && vrp_val_is_max (anti_max))
1925 if (!supports_overflow_infinity (TREE_TYPE (var_vr->min)))
1927 set_value_range_to_varying (vr_p);
1930 min = positive_overflow_infinity (TREE_TYPE (var_vr->min));
1932 else if (!POINTER_TYPE_P (TREE_TYPE (var_vr->min)))
1934 if (TYPE_PRECISION (TREE_TYPE (var_vr->min)) == 1
1935 && !TYPE_UNSIGNED (TREE_TYPE (var_vr->min)))
1936 min = fold_build2 (MINUS_EXPR, TREE_TYPE (var_vr->min),
1938 build_int_cst (TREE_TYPE (var_vr->min),
1941 min = fold_build2 (PLUS_EXPR, TREE_TYPE (var_vr->min),
1943 build_int_cst (TREE_TYPE (var_vr->min),
1947 min = fold_build_pointer_plus_hwi (anti_max, 1);
1949 set_value_range (vr_p, VR_RANGE, min, max, vr_p->equiv);
1951 /* Case 3b, the anti-range extends into the high
1952 part of the real range. Thus creating a new
1953 higher for the real range. */
1954 else if (compare_values (anti_min, real_min) == 1
1955 && ((cmp = compare_values (anti_min, real_max)) == -1
1958 gcc_assert (!is_negative_overflow_infinity (anti_min));
1959 if (needs_overflow_infinity (TREE_TYPE (anti_min))
1960 && vrp_val_is_min (anti_min))
1962 if (!supports_overflow_infinity (TREE_TYPE (var_vr->min)))
1964 set_value_range_to_varying (vr_p);
1967 max = negative_overflow_infinity (TREE_TYPE (var_vr->min));
1969 else if (!POINTER_TYPE_P (TREE_TYPE (var_vr->min)))
1971 if (TYPE_PRECISION (TREE_TYPE (var_vr->min)) == 1
1972 && !TYPE_UNSIGNED (TREE_TYPE (var_vr->min)))
1973 max = fold_build2 (PLUS_EXPR, TREE_TYPE (var_vr->min),
1975 build_int_cst (TREE_TYPE (var_vr->min),
1978 max = fold_build2 (MINUS_EXPR, TREE_TYPE (var_vr->min),
1980 build_int_cst (TREE_TYPE (var_vr->min),
1984 max = fold_build_pointer_plus_hwi (anti_min, -1);
1986 set_value_range (vr_p, VR_RANGE, min, max, vr_p->equiv);
1993 /* Extract range information from SSA name VAR and store it in VR. If
1994 VAR has an interesting range, use it. Otherwise, create the
1995 range [VAR, VAR] and return it. This is useful in situations where
1996 we may have conditionals testing values of VARYING names. For
2003 Even if y_5 is deemed VARYING, we can determine that x_3 > y_5 is
2007 extract_range_from_ssa_name (value_range_t *vr, tree var)
2009 value_range_t *var_vr = get_value_range (var);
2011 if (var_vr->type != VR_UNDEFINED && var_vr->type != VR_VARYING)
2012 copy_value_range (vr, var_vr);
2014 set_value_range (vr, VR_RANGE, var, var, NULL);
2016 add_equivalence (&vr->equiv, var);
2020 /* Wrapper around int_const_binop. If the operation overflows and we
2021 are not using wrapping arithmetic, then adjust the result to be
2022 -INF or +INF depending on CODE, VAL1 and VAL2. This can return
2023 NULL_TREE if we need to use an overflow infinity representation but
2024 the type does not support it. */
2027 vrp_int_const_binop (enum tree_code code, tree val1, tree val2)
2031 res = int_const_binop (code, val1, val2);
2033 /* If we are using unsigned arithmetic, operate symbolically
2034 on -INF and +INF as int_const_binop only handles signed overflow. */
2035 if (TYPE_UNSIGNED (TREE_TYPE (val1)))
2037 int checkz = compare_values (res, val1);
2038 bool overflow = false;
2040 /* Ensure that res = val1 [+*] val2 >= val1
2041 or that res = val1 - val2 <= val1. */
2042 if ((code == PLUS_EXPR
2043 && !(checkz == 1 || checkz == 0))
2044 || (code == MINUS_EXPR
2045 && !(checkz == 0 || checkz == -1)))
2049 /* Checking for multiplication overflow is done by dividing the
2050 output of the multiplication by the first input of the
2051 multiplication. If the result of that division operation is
2052 not equal to the second input of the multiplication, then the
2053 multiplication overflowed. */
2054 else if (code == MULT_EXPR && !integer_zerop (val1))
2056 tree tmp = int_const_binop (TRUNC_DIV_EXPR,
2059 int check = compare_values (tmp, val2);
2067 res = copy_node (res);
2068 TREE_OVERFLOW (res) = 1;
2072 else if (TYPE_OVERFLOW_WRAPS (TREE_TYPE (val1)))
2073 /* If the singed operation wraps then int_const_binop has done
2074 everything we want. */
2076 else if ((TREE_OVERFLOW (res)
2077 && !TREE_OVERFLOW (val1)
2078 && !TREE_OVERFLOW (val2))
2079 || is_overflow_infinity (val1)
2080 || is_overflow_infinity (val2))
2082 /* If the operation overflowed but neither VAL1 nor VAL2 are
2083 overflown, return -INF or +INF depending on the operation
2084 and the combination of signs of the operands. */
2085 int sgn1 = tree_int_cst_sgn (val1);
2086 int sgn2 = tree_int_cst_sgn (val2);
2088 if (needs_overflow_infinity (TREE_TYPE (res))
2089 && !supports_overflow_infinity (TREE_TYPE (res)))
2092 /* We have to punt on adding infinities of different signs,
2093 since we can't tell what the sign of the result should be.
2094 Likewise for subtracting infinities of the same sign. */
2095 if (((code == PLUS_EXPR && sgn1 != sgn2)
2096 || (code == MINUS_EXPR && sgn1 == sgn2))
2097 && is_overflow_infinity (val1)
2098 && is_overflow_infinity (val2))
2101 /* Don't try to handle division or shifting of infinities. */
2102 if ((code == TRUNC_DIV_EXPR
2103 || code == FLOOR_DIV_EXPR
2104 || code == CEIL_DIV_EXPR
2105 || code == EXACT_DIV_EXPR
2106 || code == ROUND_DIV_EXPR
2107 || code == RSHIFT_EXPR)
2108 && (is_overflow_infinity (val1)
2109 || is_overflow_infinity (val2)))
2112 /* Notice that we only need to handle the restricted set of
2113 operations handled by extract_range_from_binary_expr.
2114 Among them, only multiplication, addition and subtraction
2115 can yield overflow without overflown operands because we
2116 are working with integral types only... except in the
2117 case VAL1 = -INF and VAL2 = -1 which overflows to +INF
2118 for division too. */
2120 /* For multiplication, the sign of the overflow is given
2121 by the comparison of the signs of the operands. */
2122 if ((code == MULT_EXPR && sgn1 == sgn2)
2123 /* For addition, the operands must be of the same sign
2124 to yield an overflow. Its sign is therefore that
2125 of one of the operands, for example the first. For
2126 infinite operands X + -INF is negative, not positive. */
2127 || (code == PLUS_EXPR
2129 ? !is_negative_overflow_infinity (val2)
2130 : is_positive_overflow_infinity (val2)))
2131 /* For subtraction, non-infinite operands must be of
2132 different signs to yield an overflow. Its sign is
2133 therefore that of the first operand or the opposite of
2134 that of the second operand. A first operand of 0 counts
2135 as positive here, for the corner case 0 - (-INF), which
2136 overflows, but must yield +INF. For infinite operands 0
2137 - INF is negative, not positive. */
2138 || (code == MINUS_EXPR
2140 ? !is_positive_overflow_infinity (val2)
2141 : is_negative_overflow_infinity (val2)))
2142 /* We only get in here with positive shift count, so the
2143 overflow direction is the same as the sign of val1.
2144 Actually rshift does not overflow at all, but we only
2145 handle the case of shifting overflowed -INF and +INF. */
2146 || (code == RSHIFT_EXPR
2148 /* For division, the only case is -INF / -1 = +INF. */
2149 || code == TRUNC_DIV_EXPR
2150 || code == FLOOR_DIV_EXPR
2151 || code == CEIL_DIV_EXPR
2152 || code == EXACT_DIV_EXPR
2153 || code == ROUND_DIV_EXPR)
2154 return (needs_overflow_infinity (TREE_TYPE (res))
2155 ? positive_overflow_infinity (TREE_TYPE (res))
2156 : TYPE_MAX_VALUE (TREE_TYPE (res)));
2158 return (needs_overflow_infinity (TREE_TYPE (res))
2159 ? negative_overflow_infinity (TREE_TYPE (res))
2160 : TYPE_MIN_VALUE (TREE_TYPE (res)));
2167 /* For range VR compute two double_int bitmasks. In *MAY_BE_NONZERO
2168 bitmask if some bit is unset, it means for all numbers in the range
2169 the bit is 0, otherwise it might be 0 or 1. In *MUST_BE_NONZERO
2170 bitmask if some bit is set, it means for all numbers in the range
2171 the bit is 1, otherwise it might be 0 or 1. */
2174 zero_nonzero_bits_from_vr (value_range_t *vr,
2175 double_int *may_be_nonzero,
2176 double_int *must_be_nonzero)
2178 *may_be_nonzero = double_int_minus_one;
2179 *must_be_nonzero = double_int_zero;
2180 if (!range_int_cst_p (vr))
2183 if (range_int_cst_singleton_p (vr))
2185 *may_be_nonzero = tree_to_double_int (vr->min);
2186 *must_be_nonzero = *may_be_nonzero;
2188 else if (tree_int_cst_sgn (vr->min) >= 0
2189 || tree_int_cst_sgn (vr->max) < 0)
2191 double_int dmin = tree_to_double_int (vr->min);
2192 double_int dmax = tree_to_double_int (vr->max);
2193 double_int xor_mask = double_int_xor (dmin, dmax);
2194 *may_be_nonzero = double_int_ior (dmin, dmax);
2195 *must_be_nonzero = double_int_and (dmin, dmax);
2196 if (xor_mask.high != 0)
2198 unsigned HOST_WIDE_INT mask
2199 = ((unsigned HOST_WIDE_INT) 1
2200 << floor_log2 (xor_mask.high)) - 1;
2201 may_be_nonzero->low = ALL_ONES;
2202 may_be_nonzero->high |= mask;
2203 must_be_nonzero->low = 0;
2204 must_be_nonzero->high &= ~mask;
2206 else if (xor_mask.low != 0)
2208 unsigned HOST_WIDE_INT mask
2209 = ((unsigned HOST_WIDE_INT) 1
2210 << floor_log2 (xor_mask.low)) - 1;
2211 may_be_nonzero->low |= mask;
2212 must_be_nonzero->low &= ~mask;
2219 /* Helper to extract a value-range *VR for a multiplicative operation
2223 extract_range_from_multiplicative_op_1 (value_range_t *vr,
2224 enum tree_code code,
2225 value_range_t *vr0, value_range_t *vr1)
2227 enum value_range_type type;
2234 /* Multiplications, divisions and shifts are a bit tricky to handle,
2235 depending on the mix of signs we have in the two ranges, we
2236 need to operate on different values to get the minimum and
2237 maximum values for the new range. One approach is to figure
2238 out all the variations of range combinations and do the
2241 However, this involves several calls to compare_values and it
2242 is pretty convoluted. It's simpler to do the 4 operations
2243 (MIN0 OP MIN1, MIN0 OP MAX1, MAX0 OP MIN1 and MAX0 OP MAX0 OP
2244 MAX1) and then figure the smallest and largest values to form
2246 gcc_assert (code == MULT_EXPR
2247 || code == TRUNC_DIV_EXPR
2248 || code == FLOOR_DIV_EXPR
2249 || code == CEIL_DIV_EXPR
2250 || code == EXACT_DIV_EXPR
2251 || code == ROUND_DIV_EXPR
2252 || code == RSHIFT_EXPR);
2253 gcc_assert ((vr0->type == VR_RANGE
2254 || (code == MULT_EXPR && vr0->type == VR_ANTI_RANGE))
2255 && vr0->type == vr1->type);
2259 /* Compute the 4 cross operations. */
2261 val[0] = vrp_int_const_binop (code, vr0->min, vr1->min);
2262 if (val[0] == NULL_TREE)
2265 if (vr1->max == vr1->min)
2269 val[1] = vrp_int_const_binop (code, vr0->min, vr1->max);
2270 if (val[1] == NULL_TREE)
2274 if (vr0->max == vr0->min)
2278 val[2] = vrp_int_const_binop (code, vr0->max, vr1->min);
2279 if (val[2] == NULL_TREE)
2283 if (vr0->min == vr0->max || vr1->min == vr1->max)
2287 val[3] = vrp_int_const_binop (code, vr0->max, vr1->max);
2288 if (val[3] == NULL_TREE)
2294 set_value_range_to_varying (vr);
2298 /* Set MIN to the minimum of VAL[i] and MAX to the maximum
2302 for (i = 1; i < 4; i++)
2304 if (!is_gimple_min_invariant (min)
2305 || (TREE_OVERFLOW (min) && !is_overflow_infinity (min))
2306 || !is_gimple_min_invariant (max)
2307 || (TREE_OVERFLOW (max) && !is_overflow_infinity (max)))
2312 if (!is_gimple_min_invariant (val[i])
2313 || (TREE_OVERFLOW (val[i])
2314 && !is_overflow_infinity (val[i])))
2316 /* If we found an overflowed value, set MIN and MAX
2317 to it so that we set the resulting range to
2323 if (compare_values (val[i], min) == -1)
2326 if (compare_values (val[i], max) == 1)
2331 /* If either MIN or MAX overflowed, then set the resulting range to
2332 VARYING. But we do accept an overflow infinity
2334 if (min == NULL_TREE
2335 || !is_gimple_min_invariant (min)
2336 || (TREE_OVERFLOW (min) && !is_overflow_infinity (min))
2338 || !is_gimple_min_invariant (max)
2339 || (TREE_OVERFLOW (max) && !is_overflow_infinity (max)))
2341 set_value_range_to_varying (vr);
2347 2) [-INF, +-INF(OVF)]
2348 3) [+-INF(OVF), +INF]
2349 4) [+-INF(OVF), +-INF(OVF)]
2350 We learn nothing when we have INF and INF(OVF) on both sides.
2351 Note that we do accept [-INF, -INF] and [+INF, +INF] without
2353 if ((vrp_val_is_min (min) || is_overflow_infinity (min))
2354 && (vrp_val_is_max (max) || is_overflow_infinity (max)))
2356 set_value_range_to_varying (vr);
2360 cmp = compare_values (min, max);
2361 if (cmp == -2 || cmp == 1)
2363 /* If the new range has its limits swapped around (MIN > MAX),
2364 then the operation caused one of them to wrap around, mark
2365 the new range VARYING. */
2366 set_value_range_to_varying (vr);
2369 set_value_range (vr, type, min, max, NULL);
2372 /* Extract range information from a binary operation CODE based on
2373 the ranges of each of its operands, *VR0 and *VR1 with resulting
2374 type EXPR_TYPE. The resulting range is stored in *VR. */
2377 extract_range_from_binary_expr_1 (value_range_t *vr,
2378 enum tree_code code, tree expr_type,
2379 value_range_t *vr0_, value_range_t *vr1_)
2381 value_range_t vr0 = *vr0_, vr1 = *vr1_;
2382 enum value_range_type type;
2383 tree min = NULL_TREE, max = NULL_TREE;
2386 if (!INTEGRAL_TYPE_P (expr_type)
2387 && !POINTER_TYPE_P (expr_type))
2389 set_value_range_to_varying (vr);
2393 /* Not all binary expressions can be applied to ranges in a
2394 meaningful way. Handle only arithmetic operations. */
2395 if (code != PLUS_EXPR
2396 && code != MINUS_EXPR
2397 && code != POINTER_PLUS_EXPR
2398 && code != MULT_EXPR
2399 && code != TRUNC_DIV_EXPR
2400 && code != FLOOR_DIV_EXPR
2401 && code != CEIL_DIV_EXPR
2402 && code != EXACT_DIV_EXPR
2403 && code != ROUND_DIV_EXPR
2404 && code != TRUNC_MOD_EXPR
2405 && code != RSHIFT_EXPR
2408 && code != BIT_AND_EXPR
2409 && code != BIT_IOR_EXPR
2410 && code != BIT_XOR_EXPR)
2412 set_value_range_to_varying (vr);
2416 /* If both ranges are UNDEFINED, so is the result. */
2417 if (vr0.type == VR_UNDEFINED && vr1.type == VR_UNDEFINED)
2419 set_value_range_to_undefined (vr);
2422 /* If one of the ranges is UNDEFINED drop it to VARYING for the following
2423 code. At some point we may want to special-case operations that
2424 have UNDEFINED result for all or some value-ranges of the not UNDEFINED
2426 else if (vr0.type == VR_UNDEFINED)
2427 set_value_range_to_varying (&vr0);
2428 else if (vr1.type == VR_UNDEFINED)
2429 set_value_range_to_varying (&vr1);
2431 /* The type of the resulting value range defaults to VR0.TYPE. */
2434 /* Refuse to operate on VARYING ranges, ranges of different kinds
2435 and symbolic ranges. As an exception, we allow BIT_AND_EXPR
2436 because we may be able to derive a useful range even if one of
2437 the operands is VR_VARYING or symbolic range. Similarly for
2438 divisions. TODO, we may be able to derive anti-ranges in
2440 if (code != BIT_AND_EXPR
2441 && code != BIT_IOR_EXPR
2442 && code != TRUNC_DIV_EXPR
2443 && code != FLOOR_DIV_EXPR
2444 && code != CEIL_DIV_EXPR
2445 && code != EXACT_DIV_EXPR
2446 && code != ROUND_DIV_EXPR
2447 && code != TRUNC_MOD_EXPR
2448 && (vr0.type == VR_VARYING
2449 || vr1.type == VR_VARYING
2450 || vr0.type != vr1.type
2451 || symbolic_range_p (&vr0)
2452 || symbolic_range_p (&vr1)))
2454 set_value_range_to_varying (vr);
2458 /* Now evaluate the expression to determine the new range. */
2459 if (POINTER_TYPE_P (expr_type))
2461 if (code == MIN_EXPR || code == MAX_EXPR)
2463 /* For MIN/MAX expressions with pointers, we only care about
2464 nullness, if both are non null, then the result is nonnull.
2465 If both are null, then the result is null. Otherwise they
2467 if (range_is_nonnull (&vr0) && range_is_nonnull (&vr1))
2468 set_value_range_to_nonnull (vr, expr_type);
2469 else if (range_is_null (&vr0) && range_is_null (&vr1))
2470 set_value_range_to_null (vr, expr_type);
2472 set_value_range_to_varying (vr);
2474 else if (code == POINTER_PLUS_EXPR)
2476 /* For pointer types, we are really only interested in asserting
2477 whether the expression evaluates to non-NULL. */
2478 if (range_is_nonnull (&vr0) || range_is_nonnull (&vr1))
2479 set_value_range_to_nonnull (vr, expr_type);
2480 else if (range_is_null (&vr0) && range_is_null (&vr1))
2481 set_value_range_to_null (vr, expr_type);
2483 set_value_range_to_varying (vr);
2485 else if (code == BIT_AND_EXPR)
2487 /* For pointer types, we are really only interested in asserting
2488 whether the expression evaluates to non-NULL. */
2489 if (range_is_nonnull (&vr0) && range_is_nonnull (&vr1))
2490 set_value_range_to_nonnull (vr, expr_type);
2491 else if (range_is_null (&vr0) || range_is_null (&vr1))
2492 set_value_range_to_null (vr, expr_type);
2494 set_value_range_to_varying (vr);
2497 set_value_range_to_varying (vr);
2502 /* For integer ranges, apply the operation to each end of the
2503 range and see what we end up with. */
2504 if (code == PLUS_EXPR)
2506 /* If we have a PLUS_EXPR with two VR_ANTI_RANGEs, drop to
2507 VR_VARYING. It would take more effort to compute a precise
2508 range for such a case. For example, if we have op0 == 1 and
2509 op1 == -1 with their ranges both being ~[0,0], we would have
2510 op0 + op1 == 0, so we cannot claim that the sum is in ~[0,0].
2511 Note that we are guaranteed to have vr0.type == vr1.type at
2513 if (vr0.type == VR_ANTI_RANGE)
2515 set_value_range_to_varying (vr);
2519 /* For operations that make the resulting range directly
2520 proportional to the original ranges, apply the operation to
2521 the same end of each range. */
2522 min = vrp_int_const_binop (code, vr0.min, vr1.min);
2523 max = vrp_int_const_binop (code, vr0.max, vr1.max);
2525 /* If both additions overflowed the range kind is still correct.
2526 This happens regularly with subtracting something in unsigned
2528 ??? See PR30318 for all the cases we do not handle. */
2529 if ((TREE_OVERFLOW (min) && !is_overflow_infinity (min))
2530 && (TREE_OVERFLOW (max) && !is_overflow_infinity (max)))
2532 min = build_int_cst_wide (TREE_TYPE (min),
2533 TREE_INT_CST_LOW (min),
2534 TREE_INT_CST_HIGH (min));
2535 max = build_int_cst_wide (TREE_TYPE (max),
2536 TREE_INT_CST_LOW (max),
2537 TREE_INT_CST_HIGH (max));
2540 else if (code == MIN_EXPR
2541 || code == MAX_EXPR)
2543 if (vr0.type == VR_ANTI_RANGE)
2545 /* For MIN_EXPR and MAX_EXPR with two VR_ANTI_RANGEs,
2546 the resulting VR_ANTI_RANGE is the same - intersection
2547 of the two ranges. */
2548 min = vrp_int_const_binop (MAX_EXPR, vr0.min, vr1.min);
2549 max = vrp_int_const_binop (MIN_EXPR, vr0.max, vr1.max);
2553 /* For operations that make the resulting range directly
2554 proportional to the original ranges, apply the operation to
2555 the same end of each range. */
2556 min = vrp_int_const_binop (code, vr0.min, vr1.min);
2557 max = vrp_int_const_binop (code, vr0.max, vr1.max);
2560 else if (code == MULT_EXPR)
2562 /* If we have an unsigned MULT_EXPR with two VR_ANTI_RANGEs,
2563 drop to VR_VARYING. It would take more effort to compute a
2564 precise range for such a case. For example, if we have
2565 op0 == 65536 and op1 == 65536 with their ranges both being
2566 ~[0,0] on a 32-bit machine, we would have op0 * op1 == 0, so
2567 we cannot claim that the product is in ~[0,0]. Note that we
2568 are guaranteed to have vr0.type == vr1.type at this
2570 if (vr0.type == VR_ANTI_RANGE
2571 && !TYPE_OVERFLOW_UNDEFINED (expr_type))
2573 set_value_range_to_varying (vr);
2577 extract_range_from_multiplicative_op_1 (vr, code, &vr0, &vr1);
2580 else if (code == RSHIFT_EXPR)
2582 /* If we have a RSHIFT_EXPR with any shift values outside [0..prec-1],
2583 then drop to VR_VARYING. Outside of this range we get undefined
2584 behavior from the shift operation. We cannot even trust
2585 SHIFT_COUNT_TRUNCATED at this stage, because that applies to rtl
2586 shifts, and the operation at the tree level may be widened. */
2587 if (vr1.type != VR_RANGE
2588 || !value_range_nonnegative_p (&vr1)
2589 || TREE_CODE (vr1.max) != INTEGER_CST
2590 || compare_tree_int (vr1.max, TYPE_PRECISION (expr_type) - 1) == 1)
2592 set_value_range_to_varying (vr);
2596 extract_range_from_multiplicative_op_1 (vr, code, &vr0, &vr1);
2599 else if (code == TRUNC_DIV_EXPR
2600 || code == FLOOR_DIV_EXPR
2601 || code == CEIL_DIV_EXPR
2602 || code == EXACT_DIV_EXPR
2603 || code == ROUND_DIV_EXPR)
2605 if (vr0.type != VR_RANGE || symbolic_range_p (&vr0))
2607 /* For division, if op1 has VR_RANGE but op0 does not, something
2608 can be deduced just from that range. Say [min, max] / [4, max]
2609 gives [min / 4, max / 4] range. */
2610 if (vr1.type == VR_RANGE
2611 && !symbolic_range_p (&vr1)
2612 && !range_includes_zero_p (&vr1))
2614 vr0.type = type = VR_RANGE;
2615 vr0.min = vrp_val_min (expr_type);
2616 vr0.max = vrp_val_max (expr_type);
2620 set_value_range_to_varying (vr);
2625 /* For divisions, if flag_non_call_exceptions is true, we must
2626 not eliminate a division by zero. */
2627 if (cfun->can_throw_non_call_exceptions
2628 && (vr1.type != VR_RANGE
2629 || symbolic_range_p (&vr1)
2630 || range_includes_zero_p (&vr1)))
2632 set_value_range_to_varying (vr);
2636 /* For divisions, if op0 is VR_RANGE, we can deduce a range
2637 even if op1 is VR_VARYING, VR_ANTI_RANGE, symbolic or can
2639 if (vr0.type == VR_RANGE
2640 && (vr1.type != VR_RANGE
2641 || symbolic_range_p (&vr1)
2642 || range_includes_zero_p (&vr1)))
2644 tree zero = build_int_cst (TREE_TYPE (vr0.min), 0);
2649 if (TYPE_UNSIGNED (expr_type)
2650 || value_range_nonnegative_p (&vr1))
2652 /* For unsigned division or when divisor is known
2653 to be non-negative, the range has to cover
2654 all numbers from 0 to max for positive max
2655 and all numbers from min to 0 for negative min. */
2656 cmp = compare_values (vr0.max, zero);
2659 else if (cmp == 0 || cmp == 1)
2663 cmp = compare_values (vr0.min, zero);
2666 else if (cmp == 0 || cmp == -1)
2673 /* Otherwise the range is -max .. max or min .. -min
2674 depending on which bound is bigger in absolute value,
2675 as the division can change the sign. */
2676 abs_extent_range (vr, vr0.min, vr0.max);
2679 if (type == VR_VARYING)
2681 set_value_range_to_varying (vr);
2687 extract_range_from_multiplicative_op_1 (vr, code, &vr0, &vr1);
2691 else if (code == TRUNC_MOD_EXPR)
2693 if (vr1.type != VR_RANGE
2694 || symbolic_range_p (&vr1)
2695 || range_includes_zero_p (&vr1)
2696 || vrp_val_is_min (vr1.min))
2698 set_value_range_to_varying (vr);
2702 /* Compute MAX <|vr1.min|, |vr1.max|> - 1. */
2703 max = fold_unary_to_constant (ABS_EXPR, expr_type, vr1.min);
2704 if (tree_int_cst_lt (max, vr1.max))
2706 max = int_const_binop (MINUS_EXPR, max, integer_one_node);
2707 /* If the dividend is non-negative the modulus will be
2708 non-negative as well. */
2709 if (TYPE_UNSIGNED (expr_type)
2710 || value_range_nonnegative_p (&vr0))
2711 min = build_int_cst (TREE_TYPE (max), 0);
2713 min = fold_unary_to_constant (NEGATE_EXPR, expr_type, max);
2715 else if (code == MINUS_EXPR)
2717 /* If we have a MINUS_EXPR with two VR_ANTI_RANGEs, drop to
2718 VR_VARYING. It would take more effort to compute a precise
2719 range for such a case. For example, if we have op0 == 1 and
2720 op1 == 1 with their ranges both being ~[0,0], we would have
2721 op0 - op1 == 0, so we cannot claim that the difference is in
2722 ~[0,0]. Note that we are guaranteed to have
2723 vr0.type == vr1.type at this point. */
2724 if (vr0.type == VR_ANTI_RANGE)
2726 set_value_range_to_varying (vr);
2730 /* For MINUS_EXPR, apply the operation to the opposite ends of
2732 min = vrp_int_const_binop (code, vr0.min, vr1.max);
2733 max = vrp_int_const_binop (code, vr0.max, vr1.min);
2735 else if (code == BIT_AND_EXPR || code == BIT_IOR_EXPR || code == BIT_XOR_EXPR)
2737 bool int_cst_range0, int_cst_range1;
2738 double_int may_be_nonzero0, may_be_nonzero1;
2739 double_int must_be_nonzero0, must_be_nonzero1;
2741 int_cst_range0 = zero_nonzero_bits_from_vr (&vr0, &may_be_nonzero0,
2743 int_cst_range1 = zero_nonzero_bits_from_vr (&vr1, &may_be_nonzero1,
2747 if (code == BIT_AND_EXPR)
2750 min = double_int_to_tree (expr_type,
2751 double_int_and (must_be_nonzero0,
2753 dmax = double_int_and (may_be_nonzero0, may_be_nonzero1);
2754 /* If both input ranges contain only negative values we can
2755 truncate the result range maximum to the minimum of the
2756 input range maxima. */
2757 if (int_cst_range0 && int_cst_range1
2758 && tree_int_cst_sgn (vr0.max) < 0
2759 && tree_int_cst_sgn (vr1.max) < 0)
2761 dmax = double_int_min (dmax, tree_to_double_int (vr0.max),
2762 TYPE_UNSIGNED (expr_type));
2763 dmax = double_int_min (dmax, tree_to_double_int (vr1.max),
2764 TYPE_UNSIGNED (expr_type));
2766 /* If either input range contains only non-negative values
2767 we can truncate the result range maximum to the respective
2768 maximum of the input range. */
2769 if (int_cst_range0 && tree_int_cst_sgn (vr0.min) >= 0)
2770 dmax = double_int_min (dmax, tree_to_double_int (vr0.max),
2771 TYPE_UNSIGNED (expr_type));
2772 if (int_cst_range1 && tree_int_cst_sgn (vr1.min) >= 0)
2773 dmax = double_int_min (dmax, tree_to_double_int (vr1.max),
2774 TYPE_UNSIGNED (expr_type));
2775 max = double_int_to_tree (expr_type, dmax);
2777 else if (code == BIT_IOR_EXPR)
2780 max = double_int_to_tree (expr_type,
2781 double_int_ior (may_be_nonzero0,
2783 dmin = double_int_ior (must_be_nonzero0, must_be_nonzero1);
2784 /* If the input ranges contain only positive values we can
2785 truncate the minimum of the result range to the maximum
2786 of the input range minima. */
2787 if (int_cst_range0 && int_cst_range1
2788 && tree_int_cst_sgn (vr0.min) >= 0
2789 && tree_int_cst_sgn (vr1.min) >= 0)
2791 dmin = double_int_max (dmin, tree_to_double_int (vr0.min),
2792 TYPE_UNSIGNED (expr_type));
2793 dmin = double_int_max (dmin, tree_to_double_int (vr1.min),
2794 TYPE_UNSIGNED (expr_type));
2796 /* If either input range contains only negative values
2797 we can truncate the minimum of the result range to the
2798 respective minimum range. */
2799 if (int_cst_range0 && tree_int_cst_sgn (vr0.max) < 0)
2800 dmin = double_int_max (dmin, tree_to_double_int (vr0.min),
2801 TYPE_UNSIGNED (expr_type));
2802 if (int_cst_range1 && tree_int_cst_sgn (vr1.max) < 0)
2803 dmin = double_int_max (dmin, tree_to_double_int (vr1.min),
2804 TYPE_UNSIGNED (expr_type));
2805 min = double_int_to_tree (expr_type, dmin);
2807 else if (code == BIT_XOR_EXPR)
2809 double_int result_zero_bits, result_one_bits;
2811 = double_int_ior (double_int_and (must_be_nonzero0,
2814 (double_int_ior (may_be_nonzero0,
2817 = double_int_ior (double_int_and
2819 double_int_not (may_be_nonzero1)),
2822 double_int_not (may_be_nonzero0)));
2823 max = double_int_to_tree (expr_type,
2824 double_int_not (result_zero_bits));
2825 min = double_int_to_tree (expr_type, result_one_bits);
2826 /* If the range has all positive or all negative values the
2827 result is better than VARYING. */
2828 if (tree_int_cst_sgn (min) < 0
2829 || tree_int_cst_sgn (max) >= 0)
2832 max = min = NULL_TREE;
2838 /* If either MIN or MAX overflowed, then set the resulting range to
2839 VARYING. But we do accept an overflow infinity
2841 if (min == NULL_TREE
2842 || !is_gimple_min_invariant (min)
2843 || (TREE_OVERFLOW (min) && !is_overflow_infinity (min))
2845 || !is_gimple_min_invariant (max)
2846 || (TREE_OVERFLOW (max) && !is_overflow_infinity (max)))
2848 set_value_range_to_varying (vr);
2854 2) [-INF, +-INF(OVF)]
2855 3) [+-INF(OVF), +INF]
2856 4) [+-INF(OVF), +-INF(OVF)]
2857 We learn nothing when we have INF and INF(OVF) on both sides.
2858 Note that we do accept [-INF, -INF] and [+INF, +INF] without
2860 if ((vrp_val_is_min (min) || is_overflow_infinity (min))
2861 && (vrp_val_is_max (max) || is_overflow_infinity (max)))
2863 set_value_range_to_varying (vr);
2867 cmp = compare_values (min, max);
2868 if (cmp == -2 || cmp == 1)
2870 /* If the new range has its limits swapped around (MIN > MAX),
2871 then the operation caused one of them to wrap around, mark
2872 the new range VARYING. */
2873 set_value_range_to_varying (vr);
2876 set_value_range (vr, type, min, max, NULL);
2879 /* Extract range information from a binary expression OP0 CODE OP1 based on
2880 the ranges of each of its operands with resulting type EXPR_TYPE.
2881 The resulting range is stored in *VR. */
2884 extract_range_from_binary_expr (value_range_t *vr,
2885 enum tree_code code,
2886 tree expr_type, tree op0, tree op1)
2888 value_range_t vr0 = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
2889 value_range_t vr1 = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
2891 /* Get value ranges for each operand. For constant operands, create
2892 a new value range with the operand to simplify processing. */
2893 if (TREE_CODE (op0) == SSA_NAME)
2894 vr0 = *(get_value_range (op0));
2895 else if (is_gimple_min_invariant (op0))
2896 set_value_range_to_value (&vr0, op0, NULL);
2898 set_value_range_to_varying (&vr0);
2900 if (TREE_CODE (op1) == SSA_NAME)
2901 vr1 = *(get_value_range (op1));
2902 else if (is_gimple_min_invariant (op1))
2903 set_value_range_to_value (&vr1, op1, NULL);
2905 set_value_range_to_varying (&vr1);
2907 extract_range_from_binary_expr_1 (vr, code, expr_type, &vr0, &vr1);
2910 /* Extract range information from a unary operation CODE based on
2911 the range of its operand *VR0 with type OP0_TYPE with resulting type TYPE.
2912 The The resulting range is stored in *VR. */
2915 extract_range_from_unary_expr_1 (value_range_t *vr,
2916 enum tree_code code, tree type,
2917 value_range_t *vr0_, tree op0_type)
2919 value_range_t vr0 = *vr0_;
2921 /* VRP only operates on integral and pointer types. */
2922 if (!(INTEGRAL_TYPE_P (op0_type)
2923 || POINTER_TYPE_P (op0_type))
2924 || !(INTEGRAL_TYPE_P (type)
2925 || POINTER_TYPE_P (type)))
2927 set_value_range_to_varying (vr);
2931 /* If VR0 is UNDEFINED, so is the result. */
2932 if (vr0.type == VR_UNDEFINED)
2934 set_value_range_to_undefined (vr);
2938 if (CONVERT_EXPR_CODE_P (code))
2940 tree inner_type = op0_type;
2941 tree outer_type = type;
2943 /* If the expression evaluates to a pointer, we are only interested in
2944 determining if it evaluates to NULL [0, 0] or non-NULL (~[0, 0]). */
2945 if (POINTER_TYPE_P (type))
2947 if (range_is_nonnull (&vr0))
2948 set_value_range_to_nonnull (vr, type);
2949 else if (range_is_null (&vr0))
2950 set_value_range_to_null (vr, type);
2952 set_value_range_to_varying (vr);
2956 /* If VR0 is varying and we increase the type precision, assume
2957 a full range for the following transformation. */
2958 if (vr0.type == VR_VARYING
2959 && INTEGRAL_TYPE_P (inner_type)
2960 && TYPE_PRECISION (inner_type) < TYPE_PRECISION (outer_type))
2962 vr0.type = VR_RANGE;
2963 vr0.min = TYPE_MIN_VALUE (inner_type);
2964 vr0.max = TYPE_MAX_VALUE (inner_type);
2967 /* If VR0 is a constant range or anti-range and the conversion is
2968 not truncating we can convert the min and max values and
2969 canonicalize the resulting range. Otherwise we can do the
2970 conversion if the size of the range is less than what the
2971 precision of the target type can represent and the range is
2972 not an anti-range. */
2973 if ((vr0.type == VR_RANGE
2974 || vr0.type == VR_ANTI_RANGE)
2975 && TREE_CODE (vr0.min) == INTEGER_CST
2976 && TREE_CODE (vr0.max) == INTEGER_CST
2977 && (!is_overflow_infinity (vr0.min)
2978 || (vr0.type == VR_RANGE
2979 && TYPE_PRECISION (outer_type) > TYPE_PRECISION (inner_type)
2980 && needs_overflow_infinity (outer_type)
2981 && supports_overflow_infinity (outer_type)))
2982 && (!is_overflow_infinity (vr0.max)
2983 || (vr0.type == VR_RANGE
2984 && TYPE_PRECISION (outer_type) > TYPE_PRECISION (inner_type)
2985 && needs_overflow_infinity (outer_type)
2986 && supports_overflow_infinity (outer_type)))
2987 && (TYPE_PRECISION (outer_type) >= TYPE_PRECISION (inner_type)
2988 || (vr0.type == VR_RANGE
2989 && integer_zerop (int_const_binop (RSHIFT_EXPR,
2990 int_const_binop (MINUS_EXPR, vr0.max, vr0.min),
2991 size_int (TYPE_PRECISION (outer_type)))))))
2993 tree new_min, new_max;
2994 if (is_overflow_infinity (vr0.min))
2995 new_min = negative_overflow_infinity (outer_type);
2997 new_min = force_fit_type_double (outer_type,
2998 tree_to_double_int (vr0.min),
3000 if (is_overflow_infinity (vr0.max))
3001 new_max = positive_overflow_infinity (outer_type);
3003 new_max = force_fit_type_double (outer_type,
3004 tree_to_double_int (vr0.max),
3006 set_and_canonicalize_value_range (vr, vr0.type,
3007 new_min, new_max, NULL);
3011 set_value_range_to_varying (vr);
3014 else if (code == NEGATE_EXPR)
3016 /* -X is simply 0 - X, so re-use existing code that also handles
3017 anti-ranges fine. */
3018 value_range_t zero = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
3019 set_value_range_to_value (&zero, build_int_cst (type, 0), NULL);
3020 extract_range_from_binary_expr_1 (vr, MINUS_EXPR, type, &zero, &vr0);
3023 else if (code == ABS_EXPR)
3028 /* Pass through vr0 in the easy cases. */
3029 if (TYPE_UNSIGNED (type)
3030 || value_range_nonnegative_p (&vr0))
3032 copy_value_range (vr, &vr0);
3036 /* For the remaining varying or symbolic ranges we can't do anything
3038 if (vr0.type == VR_VARYING
3039 || symbolic_range_p (&vr0))
3041 set_value_range_to_varying (vr);
3045 /* -TYPE_MIN_VALUE = TYPE_MIN_VALUE with flag_wrapv so we can't get a
3047 if (!TYPE_OVERFLOW_UNDEFINED (type)
3048 && ((vr0.type == VR_RANGE
3049 && vrp_val_is_min (vr0.min))
3050 || (vr0.type == VR_ANTI_RANGE
3051 && !vrp_val_is_min (vr0.min))))
3053 set_value_range_to_varying (vr);
3057 /* ABS_EXPR may flip the range around, if the original range
3058 included negative values. */
3059 if (is_overflow_infinity (vr0.min))
3060 min = positive_overflow_infinity (type);
3061 else if (!vrp_val_is_min (vr0.min))
3062 min = fold_unary_to_constant (code, type, vr0.min);
3063 else if (!needs_overflow_infinity (type))
3064 min = TYPE_MAX_VALUE (type);
3065 else if (supports_overflow_infinity (type))
3066 min = positive_overflow_infinity (type);
3069 set_value_range_to_varying (vr);
3073 if (is_overflow_infinity (vr0.max))
3074 max = positive_overflow_infinity (type);
3075 else if (!vrp_val_is_min (vr0.max))
3076 max = fold_unary_to_constant (code, type, vr0.max);
3077 else if (!needs_overflow_infinity (type))
3078 max = TYPE_MAX_VALUE (type);
3079 else if (supports_overflow_infinity (type)
3080 /* We shouldn't generate [+INF, +INF] as set_value_range
3081 doesn't like this and ICEs. */
3082 && !is_positive_overflow_infinity (min))
3083 max = positive_overflow_infinity (type);
3086 set_value_range_to_varying (vr);
3090 cmp = compare_values (min, max);
3092 /* If a VR_ANTI_RANGEs contains zero, then we have
3093 ~[-INF, min(MIN, MAX)]. */
3094 if (vr0.type == VR_ANTI_RANGE)
3096 if (range_includes_zero_p (&vr0))
3098 /* Take the lower of the two values. */
3102 /* Create ~[-INF, min (abs(MIN), abs(MAX))]
3103 or ~[-INF + 1, min (abs(MIN), abs(MAX))] when
3104 flag_wrapv is set and the original anti-range doesn't include
3105 TYPE_MIN_VALUE, remember -TYPE_MIN_VALUE = TYPE_MIN_VALUE. */
3106 if (TYPE_OVERFLOW_WRAPS (type))
3108 tree type_min_value = TYPE_MIN_VALUE (type);
3110 min = (vr0.min != type_min_value
3111 ? int_const_binop (PLUS_EXPR, type_min_value,
3117 if (overflow_infinity_range_p (&vr0))
3118 min = negative_overflow_infinity (type);
3120 min = TYPE_MIN_VALUE (type);
3125 /* All else has failed, so create the range [0, INF], even for
3126 flag_wrapv since TYPE_MIN_VALUE is in the original
3128 vr0.type = VR_RANGE;
3129 min = build_int_cst (type, 0);
3130 if (needs_overflow_infinity (type))
3132 if (supports_overflow_infinity (type))
3133 max = positive_overflow_infinity (type);
3136 set_value_range_to_varying (vr);
3141 max = TYPE_MAX_VALUE (type);
3145 /* If the range contains zero then we know that the minimum value in the
3146 range will be zero. */
3147 else if (range_includes_zero_p (&vr0))
3151 min = build_int_cst (type, 0);
3155 /* If the range was reversed, swap MIN and MAX. */
3164 cmp = compare_values (min, max);
3165 if (cmp == -2 || cmp == 1)
3167 /* If the new range has its limits swapped around (MIN > MAX),
3168 then the operation caused one of them to wrap around, mark
3169 the new range VARYING. */
3170 set_value_range_to_varying (vr);
3173 set_value_range (vr, vr0.type, min, max, NULL);
3176 else if (code == BIT_NOT_EXPR)
3178 /* ~X is simply -1 - X, so re-use existing code that also handles
3179 anti-ranges fine. */
3180 value_range_t minusone = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
3181 set_value_range_to_value (&minusone, build_int_cst (type, -1), NULL);
3182 extract_range_from_binary_expr_1 (vr, MINUS_EXPR,
3183 type, &minusone, &vr0);
3186 else if (code == PAREN_EXPR)
3188 copy_value_range (vr, &vr0);
3192 /* For unhandled operations fall back to varying. */
3193 set_value_range_to_varying (vr);
3198 /* Extract range information from a unary expression CODE OP0 based on
3199 the range of its operand with resulting type TYPE.
3200 The resulting range is stored in *VR. */
3203 extract_range_from_unary_expr (value_range_t *vr, enum tree_code code,
3204 tree type, tree op0)
3206 value_range_t vr0 = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
3208 /* Get value ranges for the operand. For constant operands, create
3209 a new value range with the operand to simplify processing. */
3210 if (TREE_CODE (op0) == SSA_NAME)
3211 vr0 = *(get_value_range (op0));
3212 else if (is_gimple_min_invariant (op0))
3213 set_value_range_to_value (&vr0, op0, NULL);
3215 set_value_range_to_varying (&vr0);
3217 extract_range_from_unary_expr_1 (vr, code, type, &vr0, TREE_TYPE (op0));
3221 /* Extract range information from a conditional expression STMT based on
3222 the ranges of each of its operands and the expression code. */
3225 extract_range_from_cond_expr (value_range_t *vr, gimple stmt)
3228 value_range_t vr0 = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
3229 value_range_t vr1 = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
3231 /* Get value ranges for each operand. For constant operands, create
3232 a new value range with the operand to simplify processing. */
3233 op0 = gimple_assign_rhs2 (stmt);
3234 if (TREE_CODE (op0) == SSA_NAME)
3235 vr0 = *(get_value_range (op0));
3236 else if (is_gimple_min_invariant (op0))
3237 set_value_range_to_value (&vr0, op0, NULL);
3239 set_value_range_to_varying (&vr0);
3241 op1 = gimple_assign_rhs3 (stmt);
3242 if (TREE_CODE (op1) == SSA_NAME)
3243 vr1 = *(get_value_range (op1));
3244 else if (is_gimple_min_invariant (op1))
3245 set_value_range_to_value (&vr1, op1, NULL);
3247 set_value_range_to_varying (&vr1);
3249 /* The resulting value range is the union of the operand ranges */
3250 copy_value_range (vr, &vr0);
3251 vrp_meet (vr, &vr1);
3255 /* Extract range information from a comparison expression EXPR based
3256 on the range of its operand and the expression code. */
3259 extract_range_from_comparison (value_range_t *vr, enum tree_code code,
3260 tree type, tree op0, tree op1)
3265 val = vrp_evaluate_conditional_warnv_with_ops (code, op0, op1, false, &sop,
3268 /* A disadvantage of using a special infinity as an overflow
3269 representation is that we lose the ability to record overflow
3270 when we don't have an infinity. So we have to ignore a result
3271 which relies on overflow. */
3273 if (val && !is_overflow_infinity (val) && !sop)
3275 /* Since this expression was found on the RHS of an assignment,
3276 its type may be different from _Bool. Convert VAL to EXPR's
3278 val = fold_convert (type, val);
3279 if (is_gimple_min_invariant (val))
3280 set_value_range_to_value (vr, val, vr->equiv);
3282 set_value_range (vr, VR_RANGE, val, val, vr->equiv);
3285 /* The result of a comparison is always true or false. */
3286 set_value_range_to_truthvalue (vr, type);
3289 /* Try to derive a nonnegative or nonzero range out of STMT relying
3290 primarily on generic routines in fold in conjunction with range data.
3291 Store the result in *VR */
3294 extract_range_basic (value_range_t *vr, gimple stmt)
3297 tree type = gimple_expr_type (stmt);
3299 if (INTEGRAL_TYPE_P (type)
3300 && gimple_stmt_nonnegative_warnv_p (stmt, &sop))
3301 set_value_range_to_nonnegative (vr, type,
3302 sop || stmt_overflow_infinity (stmt));
3303 else if (vrp_stmt_computes_nonzero (stmt, &sop)
3305 set_value_range_to_nonnull (vr, type);
3307 set_value_range_to_varying (vr);
3311 /* Try to compute a useful range out of assignment STMT and store it
3315 extract_range_from_assignment (value_range_t *vr, gimple stmt)
3317 enum tree_code code = gimple_assign_rhs_code (stmt);
3319 if (code == ASSERT_EXPR)
3320 extract_range_from_assert (vr, gimple_assign_rhs1 (stmt));
3321 else if (code == SSA_NAME)
3322 extract_range_from_ssa_name (vr, gimple_assign_rhs1 (stmt));
3323 else if (TREE_CODE_CLASS (code) == tcc_binary)
3324 extract_range_from_binary_expr (vr, gimple_assign_rhs_code (stmt),
3325 gimple_expr_type (stmt),
3326 gimple_assign_rhs1 (stmt),
3327 gimple_assign_rhs2 (stmt));
3328 else if (TREE_CODE_CLASS (code) == tcc_unary)
3329 extract_range_from_unary_expr (vr, gimple_assign_rhs_code (stmt),
3330 gimple_expr_type (stmt),
3331 gimple_assign_rhs1 (stmt));
3332 else if (code == COND_EXPR)
3333 extract_range_from_cond_expr (vr, stmt);
3334 else if (TREE_CODE_CLASS (code) == tcc_comparison)
3335 extract_range_from_comparison (vr, gimple_assign_rhs_code (stmt),
3336 gimple_expr_type (stmt),
3337 gimple_assign_rhs1 (stmt),
3338 gimple_assign_rhs2 (stmt));
3339 else if (get_gimple_rhs_class (code) == GIMPLE_SINGLE_RHS
3340 && is_gimple_min_invariant (gimple_assign_rhs1 (stmt)))
3341 set_value_range_to_value (vr, gimple_assign_rhs1 (stmt), NULL);
3343 set_value_range_to_varying (vr);
3345 if (vr->type == VR_VARYING)
3346 extract_range_basic (vr, stmt);
3349 /* Given a range VR, a LOOP and a variable VAR, determine whether it
3350 would be profitable to adjust VR using scalar evolution information
3351 for VAR. If so, update VR with the new limits. */
3354 adjust_range_with_scev (value_range_t *vr, struct loop *loop,
3355 gimple stmt, tree var)
3357 tree init, step, chrec, tmin, tmax, min, max, type, tem;
3358 enum ev_direction dir;
3360 /* TODO. Don't adjust anti-ranges. An anti-range may provide
3361 better opportunities than a regular range, but I'm not sure. */
3362 if (vr->type == VR_ANTI_RANGE)
3365 chrec = instantiate_parameters (loop, analyze_scalar_evolution (loop, var));
3367 /* Like in PR19590, scev can return a constant function. */
3368 if (is_gimple_min_invariant (chrec))
3370 set_value_range_to_value (vr, chrec, vr->equiv);
3374 if (TREE_CODE (chrec) != POLYNOMIAL_CHREC)
3377 init = initial_condition_in_loop_num (chrec, loop->num);
3378 tem = op_with_constant_singleton_value_range (init);
3381 step = evolution_part_in_loop_num (chrec, loop->num);
3382 tem = op_with_constant_singleton_value_range (step);
3386 /* If STEP is symbolic, we can't know whether INIT will be the
3387 minimum or maximum value in the range. Also, unless INIT is
3388 a simple expression, compare_values and possibly other functions
3389 in tree-vrp won't be able to handle it. */
3390 if (step == NULL_TREE
3391 || !is_gimple_min_invariant (step)
3392 || !valid_value_p (init))
3395 dir = scev_direction (chrec);
3396 if (/* Do not adjust ranges if we do not know whether the iv increases
3397 or decreases, ... */
3398 dir == EV_DIR_UNKNOWN
3399 /* ... or if it may wrap. */
3400 || scev_probably_wraps_p (init, step, stmt, get_chrec_loop (chrec),
3404 /* We use TYPE_MIN_VALUE and TYPE_MAX_VALUE here instead of
3405 negative_overflow_infinity and positive_overflow_infinity,
3406 because we have concluded that the loop probably does not
3409 type = TREE_TYPE (var);
3410 if (POINTER_TYPE_P (type) || !TYPE_MIN_VALUE (type))
3411 tmin = lower_bound_in_type (type, type);
3413 tmin = TYPE_MIN_VALUE (type);
3414 if (POINTER_TYPE_P (type) || !TYPE_MAX_VALUE (type))
3415 tmax = upper_bound_in_type (type, type);
3417 tmax = TYPE_MAX_VALUE (type);
3419 /* Try to use estimated number of iterations for the loop to constrain the
3420 final value in the evolution. */
3421 if (TREE_CODE (step) == INTEGER_CST
3422 && is_gimple_val (init)
3423 && (TREE_CODE (init) != SSA_NAME
3424 || get_value_range (init)->type == VR_RANGE))
3428 if (estimated_loop_iterations (loop, true, &nit))
3430 value_range_t maxvr = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
3432 bool unsigned_p = TYPE_UNSIGNED (TREE_TYPE (step));
3435 dtmp = double_int_mul_with_sign (tree_to_double_int (step), nit,
3436 unsigned_p, &overflow);
3437 /* If the multiplication overflowed we can't do a meaningful
3438 adjustment. Likewise if the result doesn't fit in the type
3439 of the induction variable. For a signed type we have to
3440 check whether the result has the expected signedness which
3441 is that of the step as number of iterations is unsigned. */
3443 && double_int_fits_to_tree_p (TREE_TYPE (init), dtmp)
3445 || ((dtmp.high ^ TREE_INT_CST_HIGH (step)) >= 0)))
3447 tem = double_int_to_tree (TREE_TYPE (init), dtmp);
3448 extract_range_from_binary_expr (&maxvr, PLUS_EXPR,
3449 TREE_TYPE (init), init, tem);
3450 /* Likewise if the addition did. */
3451 if (maxvr.type == VR_RANGE)
3460 if (vr->type == VR_VARYING || vr->type == VR_UNDEFINED)
3465 /* For VARYING or UNDEFINED ranges, just about anything we get
3466 from scalar evolutions should be better. */
3468 if (dir == EV_DIR_DECREASES)
3473 /* If we would create an invalid range, then just assume we
3474 know absolutely nothing. This may be over-conservative,
3475 but it's clearly safe, and should happen only in unreachable
3476 parts of code, or for invalid programs. */
3477 if (compare_values (min, max) == 1)
3480 set_value_range (vr, VR_RANGE, min, max, vr->equiv);
3482 else if (vr->type == VR_RANGE)
3487 if (dir == EV_DIR_DECREASES)
3489 /* INIT is the maximum value. If INIT is lower than VR->MAX
3490 but no smaller than VR->MIN, set VR->MAX to INIT. */
3491 if (compare_values (init, max) == -1)
3494 /* According to the loop information, the variable does not
3495 overflow. If we think it does, probably because of an
3496 overflow due to arithmetic on a different INF value,
3498 if (is_negative_overflow_infinity (min)
3499 || compare_values (min, tmin) == -1)
3505 /* If INIT is bigger than VR->MIN, set VR->MIN to INIT. */
3506 if (compare_values (init, min) == 1)
3509 if (is_positive_overflow_infinity (max)
3510 || compare_values (tmax, max) == -1)
3514 /* If we just created an invalid range with the minimum
3515 greater than the maximum, we fail conservatively.
3516 This should happen only in unreachable
3517 parts of code, or for invalid programs. */
3518 if (compare_values (min, max) == 1)
3521 set_value_range (vr, VR_RANGE, min, max, vr->equiv);
3525 /* Return true if VAR may overflow at STMT. This checks any available
3526 loop information to see if we can determine that VAR does not
3530 vrp_var_may_overflow (tree var, gimple stmt)
3533 tree chrec, init, step;
3535 if (current_loops == NULL)
3538 l = loop_containing_stmt (stmt);
3543 chrec = instantiate_parameters (l, analyze_scalar_evolution (l, var));
3544 if (TREE_CODE (chrec) != POLYNOMIAL_CHREC)
3547 init = initial_condition_in_loop_num (chrec, l->num);
3548 step = evolution_part_in_loop_num (chrec, l->num);
3550 if (step == NULL_TREE
3551 || !is_gimple_min_invariant (step)
3552 || !valid_value_p (init))
3555 /* If we get here, we know something useful about VAR based on the
3556 loop information. If it wraps, it may overflow. */
3558 if (scev_probably_wraps_p (init, step, stmt, get_chrec_loop (chrec),
3562 if (dump_file && (dump_flags & TDF_DETAILS) != 0)
3564 print_generic_expr (dump_file, var, 0);
3565 fprintf (dump_file, ": loop information indicates does not overflow\n");
3572 /* Given two numeric value ranges VR0, VR1 and a comparison code COMP:
3574 - Return BOOLEAN_TRUE_NODE if VR0 COMP VR1 always returns true for
3575 all the values in the ranges.
3577 - Return BOOLEAN_FALSE_NODE if the comparison always returns false.
3579 - Return NULL_TREE if it is not always possible to determine the
3580 value of the comparison.
3582 Also set *STRICT_OVERFLOW_P to indicate whether a range with an
3583 overflow infinity was used in the test. */
3587 compare_ranges (enum tree_code comp, value_range_t *vr0, value_range_t *vr1,
3588 bool *strict_overflow_p)
3590 /* VARYING or UNDEFINED ranges cannot be compared. */
3591 if (vr0->type == VR_VARYING
3592 || vr0->type == VR_UNDEFINED
3593 || vr1->type == VR_VARYING
3594 || vr1->type == VR_UNDEFINED)
3597 /* Anti-ranges need to be handled separately. */
3598 if (vr0->type == VR_ANTI_RANGE || vr1->type == VR_ANTI_RANGE)
3600 /* If both are anti-ranges, then we cannot compute any
3602 if (vr0->type == VR_ANTI_RANGE && vr1->type == VR_ANTI_RANGE)
3605 /* These comparisons are never statically computable. */
3612 /* Equality can be computed only between a range and an
3613 anti-range. ~[VAL1, VAL2] == [VAL1, VAL2] is always false. */
3614 if (vr0->type == VR_RANGE)
3616 /* To simplify processing, make VR0 the anti-range. */
3617 value_range_t *tmp = vr0;
3622 gcc_assert (comp == NE_EXPR || comp == EQ_EXPR);
3624 if (compare_values_warnv (vr0->min, vr1->min, strict_overflow_p) == 0
3625 && compare_values_warnv (vr0->max, vr1->max, strict_overflow_p) == 0)
3626 return (comp == NE_EXPR) ? boolean_true_node : boolean_false_node;
3631 if (!usable_range_p (vr0, strict_overflow_p)
3632 || !usable_range_p (vr1, strict_overflow_p))
3635 /* Simplify processing. If COMP is GT_EXPR or GE_EXPR, switch the
3636 operands around and change the comparison code. */
3637 if (comp == GT_EXPR || comp == GE_EXPR)
3640 comp = (comp == GT_EXPR) ? LT_EXPR : LE_EXPR;
3646 if (comp == EQ_EXPR)
3648 /* Equality may only be computed if both ranges represent
3649 exactly one value. */
3650 if (compare_values_warnv (vr0->min, vr0->max, strict_overflow_p) == 0
3651 && compare_values_warnv (vr1->min, vr1->max, strict_overflow_p) == 0)
3653 int cmp_min = compare_values_warnv (vr0->min, vr1->min,
3655 int cmp_max = compare_values_warnv (vr0->max, vr1->max,
3657 if (cmp_min == 0 && cmp_max == 0)
3658 return boolean_true_node;
3659 else if (cmp_min != -2 && cmp_max != -2)
3660 return boolean_false_node;
3662 /* If [V0_MIN, V1_MAX] < [V1_MIN, V1_MAX] then V0 != V1. */
3663 else if (compare_values_warnv (vr0->min, vr1->max,
3664 strict_overflow_p) == 1
3665 || compare_values_warnv (vr1->min, vr0->max,
3666 strict_overflow_p) == 1)
3667 return boolean_false_node;
3671 else if (comp == NE_EXPR)
3675 /* If VR0 is completely to the left or completely to the right
3676 of VR1, they are always different. Notice that we need to
3677 make sure that both comparisons yield similar results to
3678 avoid comparing values that cannot be compared at
3680 cmp1 = compare_values_warnv (vr0->max, vr1->min, strict_overflow_p);
3681 cmp2 = compare_values_warnv (vr0->min, vr1->max, strict_overflow_p);
3682 if ((cmp1 == -1 && cmp2 == -1) || (cmp1 == 1 && cmp2 == 1))
3683 return boolean_true_node;
3685 /* If VR0 and VR1 represent a single value and are identical,
3687 else if (compare_values_warnv (vr0->min, vr0->max,
3688 strict_overflow_p) == 0
3689 && compare_values_warnv (vr1->min, vr1->max,
3690 strict_overflow_p) == 0
3691 && compare_values_warnv (vr0->min, vr1->min,
3692 strict_overflow_p) == 0
3693 && compare_values_warnv (vr0->max, vr1->max,
3694 strict_overflow_p) == 0)
3695 return boolean_false_node;
3697 /* Otherwise, they may or may not be different. */
3701 else if (comp == LT_EXPR || comp == LE_EXPR)
3705 /* If VR0 is to the left of VR1, return true. */
3706 tst = compare_values_warnv (vr0->max, vr1->min, strict_overflow_p);
3707 if ((comp == LT_EXPR && tst == -1)
3708 || (comp == LE_EXPR && (tst == -1 || tst == 0)))
3710 if (overflow_infinity_range_p (vr0)
3711 || overflow_infinity_range_p (vr1))
3712 *strict_overflow_p = true;
3713 return boolean_true_node;
3716 /* If VR0 is to the right of VR1, return false. */
3717 tst = compare_values_warnv (vr0->min, vr1->max, strict_overflow_p);
3718 if ((comp == LT_EXPR && (tst == 0 || tst == 1))
3719 || (comp == LE_EXPR && tst == 1))
3721 if (overflow_infinity_range_p (vr0)
3722 || overflow_infinity_range_p (vr1))
3723 *strict_overflow_p = true;
3724 return boolean_false_node;
3727 /* Otherwise, we don't know. */
3735 /* Given a value range VR, a value VAL and a comparison code COMP, return
3736 BOOLEAN_TRUE_NODE if VR COMP VAL always returns true for all the
3737 values in VR. Return BOOLEAN_FALSE_NODE if the comparison
3738 always returns false. Return NULL_TREE if it is not always
3739 possible to determine the value of the comparison. Also set
3740 *STRICT_OVERFLOW_P to indicate whether a range with an overflow
3741 infinity was used in the test. */
3744 compare_range_with_value (enum tree_code comp, value_range_t *vr, tree val,
3745 bool *strict_overflow_p)
3747 if (vr->type == VR_VARYING || vr->type == VR_UNDEFINED)
3750 /* Anti-ranges need to be handled separately. */
3751 if (vr->type == VR_ANTI_RANGE)
3753 /* For anti-ranges, the only predicates that we can compute at
3754 compile time are equality and inequality. */
3761 /* ~[VAL_1, VAL_2] OP VAL is known if VAL_1 <= VAL <= VAL_2. */
3762 if (value_inside_range (val, vr) == 1)
3763 return (comp == NE_EXPR) ? boolean_true_node : boolean_false_node;
3768 if (!usable_range_p (vr, strict_overflow_p))
3771 if (comp == EQ_EXPR)
3773 /* EQ_EXPR may only be computed if VR represents exactly
3775 if (compare_values_warnv (vr->min, vr->max, strict_overflow_p) == 0)
3777 int cmp = compare_values_warnv (vr->min, val, strict_overflow_p);
3779 return boolean_true_node;
3780 else if (cmp == -1 || cmp == 1 || cmp == 2)
3781 return boolean_false_node;
3783 else if (compare_values_warnv (val, vr->min, strict_overflow_p) == -1
3784 || compare_values_warnv (vr->max, val, strict_overflow_p) == -1)
3785 return boolean_false_node;
3789 else if (comp == NE_EXPR)
3791 /* If VAL is not inside VR, then they are always different. */
3792 if (compare_values_warnv (vr->max, val, strict_overflow_p) == -1
3793 || compare_values_warnv (vr->min, val, strict_overflow_p) == 1)
3794 return boolean_true_node;
3796 /* If VR represents exactly one value equal to VAL, then return
3798 if (compare_values_warnv (vr->min, vr->max, strict_overflow_p) == 0
3799 && compare_values_warnv (vr->min, val, strict_overflow_p) == 0)
3800 return boolean_false_node;
3802 /* Otherwise, they may or may not be different. */
3805 else if (comp == LT_EXPR || comp == LE_EXPR)
3809 /* If VR is to the left of VAL, return true. */
3810 tst = compare_values_warnv (vr->max, val, strict_overflow_p);
3811 if ((comp == LT_EXPR && tst == -1)
3812 || (comp == LE_EXPR && (tst == -1 || tst == 0)))
3814 if (overflow_infinity_range_p (vr))
3815 *strict_overflow_p = true;
3816 return boolean_true_node;
3819 /* If VR is to the right of VAL, return false. */
3820 tst = compare_values_warnv (vr->min, val, strict_overflow_p);
3821 if ((comp == LT_EXPR && (tst == 0 || tst == 1))
3822 || (comp == LE_EXPR && tst == 1))
3824 if (overflow_infinity_range_p (vr))
3825 *strict_overflow_p = true;
3826 return boolean_false_node;
3829 /* Otherwise, we don't know. */
3832 else if (comp == GT_EXPR || comp == GE_EXPR)
3836 /* If VR is to the right of VAL, return true. */
3837 tst = compare_values_warnv (vr->min, val, strict_overflow_p);
3838 if ((comp == GT_EXPR && tst == 1)
3839 || (comp == GE_EXPR && (tst == 0 || tst == 1)))
3841 if (overflow_infinity_range_p (vr))
3842 *strict_overflow_p = true;
3843 return boolean_true_node;
3846 /* If VR is to the left of VAL, return false. */
3847 tst = compare_values_warnv (vr->max, val, strict_overflow_p);
3848 if ((comp == GT_EXPR && (tst == -1 || tst == 0))
3849 || (comp == GE_EXPR && tst == -1))
3851 if (overflow_infinity_range_p (vr))
3852 *strict_overflow_p = true;
3853 return boolean_false_node;
3856 /* Otherwise, we don't know. */
3864 /* Debugging dumps. */
3866 void dump_value_range (FILE *, value_range_t *);
3867 void debug_value_range (value_range_t *);
3868 void dump_all_value_ranges (FILE *);
3869 void debug_all_value_ranges (void);
3870 void dump_vr_equiv (FILE *, bitmap);
3871 void debug_vr_equiv (bitmap);
3874 /* Dump value range VR to FILE. */
3877 dump_value_range (FILE *file, value_range_t *vr)
3880 fprintf (file, "[]");
3881 else if (vr->type == VR_UNDEFINED)
3882 fprintf (file, "UNDEFINED");
3883 else if (vr->type == VR_RANGE || vr->type == VR_ANTI_RANGE)
3885 tree type = TREE_TYPE (vr->min);
3887 fprintf (file, "%s[", (vr->type == VR_ANTI_RANGE) ? "~" : "");
3889 if (is_negative_overflow_infinity (vr->min))
3890 fprintf (file, "-INF(OVF)");
3891 else if (INTEGRAL_TYPE_P (type)
3892 && !TYPE_UNSIGNED (type)
3893 && vrp_val_is_min (vr->min))
3894 fprintf (file, "-INF");
3896 print_generic_expr (file, vr->min, 0);
3898 fprintf (file, ", ");
3900 if (is_positive_overflow_infinity (vr->max))
3901 fprintf (file, "+INF(OVF)");
3902 else if (INTEGRAL_TYPE_P (type)
3903 && vrp_val_is_max (vr->max))
3904 fprintf (file, "+INF");
3906 print_generic_expr (file, vr->max, 0);
3908 fprintf (file, "]");
3915 fprintf (file, " EQUIVALENCES: { ");
3917 EXECUTE_IF_SET_IN_BITMAP (vr->equiv, 0, i, bi)
3919 print_generic_expr (file, ssa_name (i), 0);
3920 fprintf (file, " ");
3924 fprintf (file, "} (%u elements)", c);
3927 else if (vr->type == VR_VARYING)
3928 fprintf (file, "VARYING");
3930 fprintf (file, "INVALID RANGE");
3934 /* Dump value range VR to stderr. */
3937 debug_value_range (value_range_t *vr)
3939 dump_value_range (stderr, vr);
3940 fprintf (stderr, "\n");
3944 /* Dump value ranges of all SSA_NAMEs to FILE. */
3947 dump_all_value_ranges (FILE *file)
3951 for (i = 0; i < num_vr_values; i++)
3955 print_generic_expr (file, ssa_name (i), 0);
3956 fprintf (file, ": ");
3957 dump_value_range (file, vr_value[i]);
3958 fprintf (file, "\n");
3962 fprintf (file, "\n");
3966 /* Dump all value ranges to stderr. */
3969 debug_all_value_ranges (void)
3971 dump_all_value_ranges (stderr);
3975 /* Given a COND_EXPR COND of the form 'V OP W', and an SSA name V,
3976 create a new SSA name N and return the assertion assignment
3977 'V = ASSERT_EXPR <V, V OP W>'. */
3980 build_assert_expr_for (tree cond, tree v)
3985 gcc_assert (TREE_CODE (v) == SSA_NAME);
3986 n = duplicate_ssa_name (v, NULL);
3988 if (COMPARISON_CLASS_P (cond))
3990 tree a = build2 (ASSERT_EXPR, TREE_TYPE (v), v, cond);
3991 assertion = gimple_build_assign (n, a);
3993 else if (TREE_CODE (cond) == SSA_NAME)
3995 /* Given V, build the assignment N = true. */
3996 gcc_assert (v == cond);
3997 assertion = gimple_build_assign (n, boolean_true_node);
4002 SSA_NAME_DEF_STMT (n) = assertion;
4004 /* The new ASSERT_EXPR, creates a new SSA name that replaces the
4005 operand of the ASSERT_EXPR. Register the new name and the old one
4006 in the replacement table so that we can fix the SSA web after
4007 adding all the ASSERT_EXPRs. */
4008 register_new_name_mapping (n, v);
4014 /* Return false if EXPR is a predicate expression involving floating
4018 fp_predicate (gimple stmt)
4020 GIMPLE_CHECK (stmt, GIMPLE_COND);
4022 return FLOAT_TYPE_P (TREE_TYPE (gimple_cond_lhs (stmt)));
4026 /* If the range of values taken by OP can be inferred after STMT executes,
4027 return the comparison code (COMP_CODE_P) and value (VAL_P) that
4028 describes the inferred range. Return true if a range could be
4032 infer_value_range (gimple stmt, tree op, enum tree_code *comp_code_p, tree *val_p)
4035 *comp_code_p = ERROR_MARK;
4037 /* Do not attempt to infer anything in names that flow through
4039 if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (op))
4042 /* Similarly, don't infer anything from statements that may throw
4044 if (stmt_could_throw_p (stmt))
4047 /* If STMT is the last statement of a basic block with no
4048 successors, there is no point inferring anything about any of its
4049 operands. We would not be able to find a proper insertion point
4050 for the assertion, anyway. */
4051 if (stmt_ends_bb_p (stmt) && EDGE_COUNT (gimple_bb (stmt)->succs) == 0)
4054 /* We can only assume that a pointer dereference will yield
4055 non-NULL if -fdelete-null-pointer-checks is enabled. */
4056 if (flag_delete_null_pointer_checks
4057 && POINTER_TYPE_P (TREE_TYPE (op))
4058 && gimple_code (stmt) != GIMPLE_ASM)
4060 unsigned num_uses, num_loads, num_stores;
4062 count_uses_and_derefs (op, stmt, &num_uses, &num_loads, &num_stores);
4063 if (num_loads + num_stores > 0)
4065 *val_p = build_int_cst (TREE_TYPE (op), 0);
4066 *comp_code_p = NE_EXPR;
4075 void dump_asserts_for (FILE *, tree);
4076 void debug_asserts_for (tree);
4077 void dump_all_asserts (FILE *);
4078 void debug_all_asserts (void);
4080 /* Dump all the registered assertions for NAME to FILE. */
4083 dump_asserts_for (FILE *file, tree name)
4087 fprintf (file, "Assertions to be inserted for ");
4088 print_generic_expr (file, name, 0);
4089 fprintf (file, "\n");
4091 loc = asserts_for[SSA_NAME_VERSION (name)];
4094 fprintf (file, "\t");
4095 print_gimple_stmt (file, gsi_stmt (loc->si), 0, 0);
4096 fprintf (file, "\n\tBB #%d", loc->bb->index);
4099 fprintf (file, "\n\tEDGE %d->%d", loc->e->src->index,
4100 loc->e->dest->index);
4101 dump_edge_info (file, loc->e, 0);
4103 fprintf (file, "\n\tPREDICATE: ");
4104 print_generic_expr (file, name, 0);
4105 fprintf (file, " %s ", tree_code_name[(int)loc->comp_code]);
4106 print_generic_expr (file, loc->val, 0);
4107 fprintf (file, "\n\n");
4111 fprintf (file, "\n");
4115 /* Dump all the registered assertions for NAME to stderr. */
4118 debug_asserts_for (tree name)
4120 dump_asserts_for (stderr, name);
4124 /* Dump all the registered assertions for all the names to FILE. */
4127 dump_all_asserts (FILE *file)
4132 fprintf (file, "\nASSERT_EXPRs to be inserted\n\n");
4133 EXECUTE_IF_SET_IN_BITMAP (need_assert_for, 0, i, bi)
4134 dump_asserts_for (file, ssa_name (i));
4135 fprintf (file, "\n");
4139 /* Dump all the registered assertions for all the names to stderr. */
4142 debug_all_asserts (void)
4144 dump_all_asserts (stderr);
4148 /* If NAME doesn't have an ASSERT_EXPR registered for asserting
4149 'EXPR COMP_CODE VAL' at a location that dominates block BB or
4150 E->DEST, then register this location as a possible insertion point
4151 for ASSERT_EXPR <NAME, EXPR COMP_CODE VAL>.
4153 BB, E and SI provide the exact insertion point for the new
4154 ASSERT_EXPR. If BB is NULL, then the ASSERT_EXPR is to be inserted
4155 on edge E. Otherwise, if E is NULL, the ASSERT_EXPR is inserted on
4156 BB. If SI points to a COND_EXPR or a SWITCH_EXPR statement, then E
4157 must not be NULL. */
4160 register_new_assert_for (tree name, tree expr,
4161 enum tree_code comp_code,
4165 gimple_stmt_iterator si)
4167 assert_locus_t n, loc, last_loc;
4168 basic_block dest_bb;
4170 gcc_checking_assert (bb == NULL || e == NULL);
4173 gcc_checking_assert (gimple_code (gsi_stmt (si)) != GIMPLE_COND
4174 && gimple_code (gsi_stmt (si)) != GIMPLE_SWITCH);
4176 /* Never build an assert comparing against an integer constant with
4177 TREE_OVERFLOW set. This confuses our undefined overflow warning
4179 if (TREE_CODE (val) == INTEGER_CST
4180 && TREE_OVERFLOW (val))
4181 val = build_int_cst_wide (TREE_TYPE (val),
4182 TREE_INT_CST_LOW (val), TREE_INT_CST_HIGH (val));
4184 /* The new assertion A will be inserted at BB or E. We need to
4185 determine if the new location is dominated by a previously
4186 registered location for A. If we are doing an edge insertion,
4187 assume that A will be inserted at E->DEST. Note that this is not
4190 If E is a critical edge, it will be split. But even if E is
4191 split, the new block will dominate the same set of blocks that
4194 The reverse, however, is not true, blocks dominated by E->DEST
4195 will not be dominated by the new block created to split E. So,
4196 if the insertion location is on a critical edge, we will not use
4197 the new location to move another assertion previously registered
4198 at a block dominated by E->DEST. */
4199 dest_bb = (bb) ? bb : e->dest;
4201 /* If NAME already has an ASSERT_EXPR registered for COMP_CODE and
4202 VAL at a block dominating DEST_BB, then we don't need to insert a new
4203 one. Similarly, if the same assertion already exists at a block
4204 dominated by DEST_BB and the new location is not on a critical
4205 edge, then update the existing location for the assertion (i.e.,
4206 move the assertion up in the dominance tree).
4208 Note, this is implemented as a simple linked list because there
4209 should not be more than a handful of assertions registered per
4210 name. If this becomes a performance problem, a table hashed by
4211 COMP_CODE and VAL could be implemented. */
4212 loc = asserts_for[SSA_NAME_VERSION (name)];
4216 if (loc->comp_code == comp_code
4218 || operand_equal_p (loc->val, val, 0))
4219 && (loc->expr == expr
4220 || operand_equal_p (loc->expr, expr, 0)))
4222 /* If the assertion NAME COMP_CODE VAL has already been
4223 registered at a basic block that dominates DEST_BB, then
4224 we don't need to insert the same assertion again. Note
4225 that we don't check strict dominance here to avoid
4226 replicating the same assertion inside the same basic
4227 block more than once (e.g., when a pointer is
4228 dereferenced several times inside a block).
4230 An exception to this rule are edge insertions. If the
4231 new assertion is to be inserted on edge E, then it will
4232 dominate all the other insertions that we may want to
4233 insert in DEST_BB. So, if we are doing an edge
4234 insertion, don't do this dominance check. */
4236 && dominated_by_p (CDI_DOMINATORS, dest_bb, loc->bb))
4239 /* Otherwise, if E is not a critical edge and DEST_BB
4240 dominates the existing location for the assertion, move
4241 the assertion up in the dominance tree by updating its
4242 location information. */
4243 if ((e == NULL || !EDGE_CRITICAL_P (e))
4244 && dominated_by_p (CDI_DOMINATORS, loc->bb, dest_bb))
4253 /* Update the last node of the list and move to the next one. */
4258 /* If we didn't find an assertion already registered for
4259 NAME COMP_CODE VAL, add a new one at the end of the list of
4260 assertions associated with NAME. */
4261 n = XNEW (struct assert_locus_d);
4265 n->comp_code = comp_code;
4273 asserts_for[SSA_NAME_VERSION (name)] = n;
4275 bitmap_set_bit (need_assert_for, SSA_NAME_VERSION (name));
4278 /* (COND_OP0 COND_CODE COND_OP1) is a predicate which uses NAME.
4279 Extract a suitable test code and value and store them into *CODE_P and
4280 *VAL_P so the predicate is normalized to NAME *CODE_P *VAL_P.
4282 If no extraction was possible, return FALSE, otherwise return TRUE.
4284 If INVERT is true, then we invert the result stored into *CODE_P. */
4287 extract_code_and_val_from_cond_with_ops (tree name, enum tree_code cond_code,
4288 tree cond_op0, tree cond_op1,
4289 bool invert, enum tree_code *code_p,
4292 enum tree_code comp_code;
4295 /* Otherwise, we have a comparison of the form NAME COMP VAL
4296 or VAL COMP NAME. */
4297 if (name == cond_op1)
4299 /* If the predicate is of the form VAL COMP NAME, flip
4300 COMP around because we need to register NAME as the
4301 first operand in the predicate. */
4302 comp_code = swap_tree_comparison (cond_code);
4307 /* The comparison is of the form NAME COMP VAL, so the
4308 comparison code remains unchanged. */
4309 comp_code = cond_code;
4313 /* Invert the comparison code as necessary. */
4315 comp_code = invert_tree_comparison (comp_code, 0);
4317 /* VRP does not handle float types. */
4318 if (SCALAR_FLOAT_TYPE_P (TREE_TYPE (val)))
4321 /* Do not register always-false predicates.
4322 FIXME: this works around a limitation in fold() when dealing with
4323 enumerations. Given 'enum { N1, N2 } x;', fold will not
4324 fold 'if (x > N2)' to 'if (0)'. */
4325 if ((comp_code == GT_EXPR || comp_code == LT_EXPR)
4326 && INTEGRAL_TYPE_P (TREE_TYPE (val)))
4328 tree min = TYPE_MIN_VALUE (TREE_TYPE (val));
4329 tree max = TYPE_MAX_VALUE (TREE_TYPE (val));
4331 if (comp_code == GT_EXPR
4333 || compare_values (val, max) == 0))
4336 if (comp_code == LT_EXPR
4338 || compare_values (val, min) == 0))
4341 *code_p = comp_code;
4346 /* Try to register an edge assertion for SSA name NAME on edge E for
4347 the condition COND contributing to the conditional jump pointed to by BSI.
4348 Invert the condition COND if INVERT is true.
4349 Return true if an assertion for NAME could be registered. */
4352 register_edge_assert_for_2 (tree name, edge e, gimple_stmt_iterator bsi,
4353 enum tree_code cond_code,
4354 tree cond_op0, tree cond_op1, bool invert)
4357 enum tree_code comp_code;
4358 bool retval = false;
4360 if (!extract_code_and_val_from_cond_with_ops (name, cond_code,
4363 invert, &comp_code, &val))
4366 /* Only register an ASSERT_EXPR if NAME was found in the sub-graph
4367 reachable from E. */
4368 if (live_on_edge (e, name)
4369 && !has_single_use (name))
4371 register_new_assert_for (name, name, comp_code, val, NULL, e, bsi);
4375 /* In the case of NAME <= CST and NAME being defined as
4376 NAME = (unsigned) NAME2 + CST2 we can assert NAME2 >= -CST2
4377 and NAME2 <= CST - CST2. We can do the same for NAME > CST.
4378 This catches range and anti-range tests. */
4379 if ((comp_code == LE_EXPR
4380 || comp_code == GT_EXPR)
4381 && TREE_CODE (val) == INTEGER_CST
4382 && TYPE_UNSIGNED (TREE_TYPE (val)))
4384 gimple def_stmt = SSA_NAME_DEF_STMT (name);
4385 tree cst2 = NULL_TREE, name2 = NULL_TREE, name3 = NULL_TREE;
4387 /* Extract CST2 from the (optional) addition. */
4388 if (is_gimple_assign (def_stmt)
4389 && gimple_assign_rhs_code (def_stmt) == PLUS_EXPR)
4391 name2 = gimple_assign_rhs1 (def_stmt);
4392 cst2 = gimple_assign_rhs2 (def_stmt);
4393 if (TREE_CODE (name2) == SSA_NAME
4394 && TREE_CODE (cst2) == INTEGER_CST)
4395 def_stmt = SSA_NAME_DEF_STMT (name2);
4398 /* Extract NAME2 from the (optional) sign-changing cast. */
4399 if (gimple_assign_cast_p (def_stmt))
4401 if (CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (def_stmt))
4402 && ! TYPE_UNSIGNED (TREE_TYPE (gimple_assign_rhs1 (def_stmt)))
4403 && (TYPE_PRECISION (gimple_expr_type (def_stmt))
4404 == TYPE_PRECISION (TREE_TYPE (gimple_assign_rhs1 (def_stmt)))))
4405 name3 = gimple_assign_rhs1 (def_stmt);
4408 /* If name3 is used later, create an ASSERT_EXPR for it. */
4409 if (name3 != NULL_TREE
4410 && TREE_CODE (name3) == SSA_NAME
4411 && (cst2 == NULL_TREE
4412 || TREE_CODE (cst2) == INTEGER_CST)
4413 && INTEGRAL_TYPE_P (TREE_TYPE (name3))
4414 && live_on_edge (e, name3)
4415 && !has_single_use (name3))
4419 /* Build an expression for the range test. */
4420 tmp = build1 (NOP_EXPR, TREE_TYPE (name), name3);
4421 if (cst2 != NULL_TREE)
4422 tmp = build2 (PLUS_EXPR, TREE_TYPE (name), tmp, cst2);
4426 fprintf (dump_file, "Adding assert for ");
4427 print_generic_expr (dump_file, name3, 0);
4428 fprintf (dump_file, " from ");
4429 print_generic_expr (dump_file, tmp, 0);
4430 fprintf (dump_file, "\n");
4433 register_new_assert_for (name3, tmp, comp_code, val, NULL, e, bsi);
4438 /* If name2 is used later, create an ASSERT_EXPR for it. */
4439 if (name2 != NULL_TREE
4440 && TREE_CODE (name2) == SSA_NAME
4441 && TREE_CODE (cst2) == INTEGER_CST
4442 && INTEGRAL_TYPE_P (TREE_TYPE (name2))
4443 && live_on_edge (e, name2)
4444 && !has_single_use (name2))
4448 /* Build an expression for the range test. */
4450 if (TREE_TYPE (name) != TREE_TYPE (name2))
4451 tmp = build1 (NOP_EXPR, TREE_TYPE (name), tmp);
4452 if (cst2 != NULL_TREE)
4453 tmp = build2 (PLUS_EXPR, TREE_TYPE (name), tmp, cst2);
4457 fprintf (dump_file, "Adding assert for ");
4458 print_generic_expr (dump_file, name2, 0);
4459 fprintf (dump_file, " from ");
4460 print_generic_expr (dump_file, tmp, 0);
4461 fprintf (dump_file, "\n");
4464 register_new_assert_for (name2, tmp, comp_code, val, NULL, e, bsi);
4473 /* OP is an operand of a truth value expression which is known to have
4474 a particular value. Register any asserts for OP and for any
4475 operands in OP's defining statement.
4477 If CODE is EQ_EXPR, then we want to register OP is zero (false),
4478 if CODE is NE_EXPR, then we want to register OP is nonzero (true). */
4481 register_edge_assert_for_1 (tree op, enum tree_code code,
4482 edge e, gimple_stmt_iterator bsi)
4484 bool retval = false;
4487 enum tree_code rhs_code;
4489 /* We only care about SSA_NAMEs. */
4490 if (TREE_CODE (op) != SSA_NAME)
4493 /* We know that OP will have a zero or nonzero value. If OP is used
4494 more than once go ahead and register an assert for OP.
4496 The FOUND_IN_SUBGRAPH support is not helpful in this situation as
4497 it will always be set for OP (because OP is used in a COND_EXPR in
4499 if (!has_single_use (op))
4501 val = build_int_cst (TREE_TYPE (op), 0);
4502 register_new_assert_for (op, op, code, val, NULL, e, bsi);
4506 /* Now look at how OP is set. If it's set from a comparison,
4507 a truth operation or some bit operations, then we may be able
4508 to register information about the operands of that assignment. */
4509 op_def = SSA_NAME_DEF_STMT (op);
4510 if (gimple_code (op_def) != GIMPLE_ASSIGN)
4513 rhs_code = gimple_assign_rhs_code (op_def);
4515 if (TREE_CODE_CLASS (rhs_code) == tcc_comparison)
4517 bool invert = (code == EQ_EXPR ? true : false);
4518 tree op0 = gimple_assign_rhs1 (op_def);
4519 tree op1 = gimple_assign_rhs2 (op_def);
4521 if (TREE_CODE (op0) == SSA_NAME)
4522 retval |= register_edge_assert_for_2 (op0, e, bsi, rhs_code, op0, op1,
4524 if (TREE_CODE (op1) == SSA_NAME)
4525 retval |= register_edge_assert_for_2 (op1, e, bsi, rhs_code, op0, op1,
4528 else if ((code == NE_EXPR
4529 && gimple_assign_rhs_code (op_def) == BIT_AND_EXPR)
4531 && gimple_assign_rhs_code (op_def) == BIT_IOR_EXPR))
4533 /* Recurse on each operand. */
4534 retval |= register_edge_assert_for_1 (gimple_assign_rhs1 (op_def),
4536 retval |= register_edge_assert_for_1 (gimple_assign_rhs2 (op_def),
4539 else if (gimple_assign_rhs_code (op_def) == BIT_NOT_EXPR
4540 && TYPE_PRECISION (TREE_TYPE (gimple_assign_lhs (op_def))) == 1)
4542 /* Recurse, flipping CODE. */
4543 code = invert_tree_comparison (code, false);
4544 retval |= register_edge_assert_for_1 (gimple_assign_rhs1 (op_def),
4547 else if (gimple_assign_rhs_code (op_def) == SSA_NAME)
4549 /* Recurse through the copy. */
4550 retval |= register_edge_assert_for_1 (gimple_assign_rhs1 (op_def),
4553 else if (CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (op_def)))
4555 /* Recurse through the type conversion. */
4556 retval |= register_edge_assert_for_1 (gimple_assign_rhs1 (op_def),
4563 /* Try to register an edge assertion for SSA name NAME on edge E for
4564 the condition COND contributing to the conditional jump pointed to by SI.
4565 Return true if an assertion for NAME could be registered. */
4568 register_edge_assert_for (tree name, edge e, gimple_stmt_iterator si,
4569 enum tree_code cond_code, tree cond_op0,
4573 enum tree_code comp_code;
4574 bool retval = false;
4575 bool is_else_edge = (e->flags & EDGE_FALSE_VALUE) != 0;
4577 /* Do not attempt to infer anything in names that flow through
4579 if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (name))
4582 if (!extract_code_and_val_from_cond_with_ops (name, cond_code,
4588 /* Register ASSERT_EXPRs for name. */
4589 retval |= register_edge_assert_for_2 (name, e, si, cond_code, cond_op0,
4590 cond_op1, is_else_edge);
4593 /* If COND is effectively an equality test of an SSA_NAME against
4594 the value zero or one, then we may be able to assert values
4595 for SSA_NAMEs which flow into COND. */
4597 /* In the case of NAME == 1 or NAME != 0, for BIT_AND_EXPR defining
4598 statement of NAME we can assert both operands of the BIT_AND_EXPR
4599 have nonzero value. */
4600 if (((comp_code == EQ_EXPR && integer_onep (val))
4601 || (comp_code == NE_EXPR && integer_zerop (val))))
4603 gimple def_stmt = SSA_NAME_DEF_STMT (name);
4605 if (is_gimple_assign (def_stmt)
4606 && gimple_assign_rhs_code (def_stmt) == BIT_AND_EXPR)
4608 tree op0 = gimple_assign_rhs1 (def_stmt);
4609 tree op1 = gimple_assign_rhs2 (def_stmt);
4610 retval |= register_edge_assert_for_1 (op0, NE_EXPR, e, si);
4611 retval |= register_edge_assert_for_1 (op1, NE_EXPR, e, si);
4615 /* In the case of NAME == 0 or NAME != 1, for BIT_IOR_EXPR defining
4616 statement of NAME we can assert both operands of the BIT_IOR_EXPR
4618 if (((comp_code == EQ_EXPR && integer_zerop (val))
4619 || (comp_code == NE_EXPR && integer_onep (val))))
4621 gimple def_stmt = SSA_NAME_DEF_STMT (name);
4623 /* For BIT_IOR_EXPR only if NAME == 0 both operands have
4624 necessarily zero value, or if type-precision is one. */
4625 if (is_gimple_assign (def_stmt)
4626 && (gimple_assign_rhs_code (def_stmt) == BIT_IOR_EXPR
4627 && (TYPE_PRECISION (TREE_TYPE (name)) == 1
4628 || comp_code == EQ_EXPR)))
4630 tree op0 = gimple_assign_rhs1 (def_stmt);
4631 tree op1 = gimple_assign_rhs2 (def_stmt);
4632 retval |= register_edge_assert_for_1 (op0, EQ_EXPR, e, si);
4633 retval |= register_edge_assert_for_1 (op1, EQ_EXPR, e, si);
4641 /* Determine whether the outgoing edges of BB should receive an
4642 ASSERT_EXPR for each of the operands of BB's LAST statement.
4643 The last statement of BB must be a COND_EXPR.
4645 If any of the sub-graphs rooted at BB have an interesting use of
4646 the predicate operands, an assert location node is added to the
4647 list of assertions for the corresponding operands. */
4650 find_conditional_asserts (basic_block bb, gimple last)
4653 gimple_stmt_iterator bsi;
4659 need_assert = false;
4660 bsi = gsi_for_stmt (last);
4662 /* Look for uses of the operands in each of the sub-graphs
4663 rooted at BB. We need to check each of the outgoing edges
4664 separately, so that we know what kind of ASSERT_EXPR to
4666 FOR_EACH_EDGE (e, ei, bb->succs)
4671 /* Register the necessary assertions for each operand in the
4672 conditional predicate. */
4673 FOR_EACH_SSA_TREE_OPERAND (op, last, iter, SSA_OP_USE)
4675 need_assert |= register_edge_assert_for (op, e, bsi,
4676 gimple_cond_code (last),
4677 gimple_cond_lhs (last),
4678 gimple_cond_rhs (last));
4691 /* Compare two case labels sorting first by the destination bb index
4692 and then by the case value. */
4695 compare_case_labels (const void *p1, const void *p2)
4697 const struct case_info *ci1 = (const struct case_info *) p1;
4698 const struct case_info *ci2 = (const struct case_info *) p2;
4699 int idx1 = ci1->bb->index;
4700 int idx2 = ci2->bb->index;
4704 else if (idx1 == idx2)
4706 /* Make sure the default label is first in a group. */
4707 if (!CASE_LOW (ci1->expr))
4709 else if (!CASE_LOW (ci2->expr))
4712 return tree_int_cst_compare (CASE_LOW (ci1->expr),
4713 CASE_LOW (ci2->expr));
4719 /* Determine whether the outgoing edges of BB should receive an
4720 ASSERT_EXPR for each of the operands of BB's LAST statement.
4721 The last statement of BB must be a SWITCH_EXPR.
4723 If any of the sub-graphs rooted at BB have an interesting use of
4724 the predicate operands, an assert location node is added to the
4725 list of assertions for the corresponding operands. */
4728 find_switch_asserts (basic_block bb, gimple last)
4731 gimple_stmt_iterator bsi;
4734 struct case_info *ci;
4735 size_t n = gimple_switch_num_labels (last);
4736 #if GCC_VERSION >= 4000
4739 /* Work around GCC 3.4 bug (PR 37086). */
4740 volatile unsigned int idx;
4743 need_assert = false;
4744 bsi = gsi_for_stmt (last);
4745 op = gimple_switch_index (last);
4746 if (TREE_CODE (op) != SSA_NAME)
4749 /* Build a vector of case labels sorted by destination label. */
4750 ci = XNEWVEC (struct case_info, n);
4751 for (idx = 0; idx < n; ++idx)
4753 ci[idx].expr = gimple_switch_label (last, idx);
4754 ci[idx].bb = label_to_block (CASE_LABEL (ci[idx].expr));
4756 qsort (ci, n, sizeof (struct case_info), compare_case_labels);
4758 for (idx = 0; idx < n; ++idx)
4761 tree cl = ci[idx].expr;
4762 basic_block cbb = ci[idx].bb;
4764 min = CASE_LOW (cl);
4765 max = CASE_HIGH (cl);
4767 /* If there are multiple case labels with the same destination
4768 we need to combine them to a single value range for the edge. */
4769 if (idx + 1 < n && cbb == ci[idx + 1].bb)
4771 /* Skip labels until the last of the group. */
4774 } while (idx < n && cbb == ci[idx].bb);
4777 /* Pick up the maximum of the case label range. */
4778 if (CASE_HIGH (ci[idx].expr))
4779 max = CASE_HIGH (ci[idx].expr);
4781 max = CASE_LOW (ci[idx].expr);
4784 /* Nothing to do if the range includes the default label until we
4785 can register anti-ranges. */
4786 if (min == NULL_TREE)
4789 /* Find the edge to register the assert expr on. */
4790 e = find_edge (bb, cbb);
4792 /* Register the necessary assertions for the operand in the
4794 need_assert |= register_edge_assert_for (op, e, bsi,
4795 max ? GE_EXPR : EQ_EXPR,
4797 fold_convert (TREE_TYPE (op),
4801 need_assert |= register_edge_assert_for (op, e, bsi, LE_EXPR,
4803 fold_convert (TREE_TYPE (op),
4813 /* Traverse all the statements in block BB looking for statements that
4814 may generate useful assertions for the SSA names in their operand.
4815 If a statement produces a useful assertion A for name N_i, then the
4816 list of assertions already generated for N_i is scanned to
4817 determine if A is actually needed.
4819 If N_i already had the assertion A at a location dominating the
4820 current location, then nothing needs to be done. Otherwise, the
4821 new location for A is recorded instead.
4823 1- For every statement S in BB, all the variables used by S are
4824 added to bitmap FOUND_IN_SUBGRAPH.
4826 2- If statement S uses an operand N in a way that exposes a known
4827 value range for N, then if N was not already generated by an
4828 ASSERT_EXPR, create a new assert location for N. For instance,
4829 if N is a pointer and the statement dereferences it, we can
4830 assume that N is not NULL.
4832 3- COND_EXPRs are a special case of #2. We can derive range
4833 information from the predicate but need to insert different
4834 ASSERT_EXPRs for each of the sub-graphs rooted at the
4835 conditional block. If the last statement of BB is a conditional
4836 expression of the form 'X op Y', then
4838 a) Remove X and Y from the set FOUND_IN_SUBGRAPH.
4840 b) If the conditional is the only entry point to the sub-graph
4841 corresponding to the THEN_CLAUSE, recurse into it. On
4842 return, if X and/or Y are marked in FOUND_IN_SUBGRAPH, then
4843 an ASSERT_EXPR is added for the corresponding variable.
4845 c) Repeat step (b) on the ELSE_CLAUSE.
4847 d) Mark X and Y in FOUND_IN_SUBGRAPH.
4856 In this case, an assertion on the THEN clause is useful to
4857 determine that 'a' is always 9 on that edge. However, an assertion
4858 on the ELSE clause would be unnecessary.
4860 4- If BB does not end in a conditional expression, then we recurse
4861 into BB's dominator children.
4863 At the end of the recursive traversal, every SSA name will have a
4864 list of locations where ASSERT_EXPRs should be added. When a new
4865 location for name N is found, it is registered by calling
4866 register_new_assert_for. That function keeps track of all the
4867 registered assertions to prevent adding unnecessary assertions.
4868 For instance, if a pointer P_4 is dereferenced more than once in a
4869 dominator tree, only the location dominating all the dereference of
4870 P_4 will receive an ASSERT_EXPR.
4872 If this function returns true, then it means that there are names
4873 for which we need to generate ASSERT_EXPRs. Those assertions are
4874 inserted by process_assert_insertions. */
4877 find_assert_locations_1 (basic_block bb, sbitmap live)
4879 gimple_stmt_iterator si;
4884 need_assert = false;
4885 last = last_stmt (bb);
4887 /* If BB's last statement is a conditional statement involving integer
4888 operands, determine if we need to add ASSERT_EXPRs. */
4890 && gimple_code (last) == GIMPLE_COND
4891 && !fp_predicate (last)
4892 && !ZERO_SSA_OPERANDS (last, SSA_OP_USE))
4893 need_assert |= find_conditional_asserts (bb, last);
4895 /* If BB's last statement is a switch statement involving integer
4896 operands, determine if we need to add ASSERT_EXPRs. */
4898 && gimple_code (last) == GIMPLE_SWITCH
4899 && !ZERO_SSA_OPERANDS (last, SSA_OP_USE))
4900 need_assert |= find_switch_asserts (bb, last);
4902 /* Traverse all the statements in BB marking used names and looking
4903 for statements that may infer assertions for their used operands. */
4904 for (si = gsi_start_bb (bb); !gsi_end_p (si); gsi_next (&si))
4910 stmt = gsi_stmt (si);
4912 if (is_gimple_debug (stmt))
4915 /* See if we can derive an assertion for any of STMT's operands. */
4916 FOR_EACH_SSA_TREE_OPERAND (op, stmt, i, SSA_OP_USE)
4919 enum tree_code comp_code;
4921 /* Mark OP in our live bitmap. */
4922 SET_BIT (live, SSA_NAME_VERSION (op));
4924 /* If OP is used in such a way that we can infer a value
4925 range for it, and we don't find a previous assertion for
4926 it, create a new assertion location node for OP. */
4927 if (infer_value_range (stmt, op, &comp_code, &value))
4929 /* If we are able to infer a nonzero value range for OP,
4930 then walk backwards through the use-def chain to see if OP
4931 was set via a typecast.
4933 If so, then we can also infer a nonzero value range
4934 for the operand of the NOP_EXPR. */
4935 if (comp_code == NE_EXPR && integer_zerop (value))
4938 gimple def_stmt = SSA_NAME_DEF_STMT (t);
4940 while (is_gimple_assign (def_stmt)
4941 && gimple_assign_rhs_code (def_stmt) == NOP_EXPR
4943 (gimple_assign_rhs1 (def_stmt)) == SSA_NAME
4945 (TREE_TYPE (gimple_assign_rhs1 (def_stmt))))
4947 t = gimple_assign_rhs1 (def_stmt);
4948 def_stmt = SSA_NAME_DEF_STMT (t);
4950 /* Note we want to register the assert for the
4951 operand of the NOP_EXPR after SI, not after the
4953 if (! has_single_use (t))
4955 register_new_assert_for (t, t, comp_code, value,
4962 /* If OP is used only once, namely in this STMT, don't
4963 bother creating an ASSERT_EXPR for it. Such an
4964 ASSERT_EXPR would do nothing but increase compile time. */
4965 if (!has_single_use (op))
4967 register_new_assert_for (op, op, comp_code, value,
4975 /* Traverse all PHI nodes in BB marking used operands. */
4976 for (si = gsi_start_phis (bb); !gsi_end_p(si); gsi_next (&si))
4978 use_operand_p arg_p;
4980 phi = gsi_stmt (si);
4982 FOR_EACH_PHI_ARG (arg_p, phi, i, SSA_OP_USE)
4984 tree arg = USE_FROM_PTR (arg_p);
4985 if (TREE_CODE (arg) == SSA_NAME)
4986 SET_BIT (live, SSA_NAME_VERSION (arg));
4993 /* Do an RPO walk over the function computing SSA name liveness
4994 on-the-fly and deciding on assert expressions to insert.
4995 Returns true if there are assert expressions to be inserted. */
4998 find_assert_locations (void)
5000 int *rpo = XCNEWVEC (int, last_basic_block + NUM_FIXED_BLOCKS);
5001 int *bb_rpo = XCNEWVEC (int, last_basic_block + NUM_FIXED_BLOCKS);
5002 int *last_rpo = XCNEWVEC (int, last_basic_block + NUM_FIXED_BLOCKS);
5006 live = XCNEWVEC (sbitmap, last_basic_block + NUM_FIXED_BLOCKS);
5007 rpo_cnt = pre_and_rev_post_order_compute (NULL, rpo, false);
5008 for (i = 0; i < rpo_cnt; ++i)
5011 need_asserts = false;
5012 for (i = rpo_cnt-1; i >= 0; --i)
5014 basic_block bb = BASIC_BLOCK (rpo[i]);
5020 live[rpo[i]] = sbitmap_alloc (num_ssa_names);
5021 sbitmap_zero (live[rpo[i]]);
5024 /* Process BB and update the live information with uses in
5026 need_asserts |= find_assert_locations_1 (bb, live[rpo[i]]);
5028 /* Merge liveness into the predecessor blocks and free it. */
5029 if (!sbitmap_empty_p (live[rpo[i]]))
5032 FOR_EACH_EDGE (e, ei, bb->preds)
5034 int pred = e->src->index;
5035 if (e->flags & EDGE_DFS_BACK)
5040 live[pred] = sbitmap_alloc (num_ssa_names);
5041 sbitmap_zero (live[pred]);
5043 sbitmap_a_or_b (live[pred], live[pred], live[rpo[i]]);
5045 if (bb_rpo[pred] < pred_rpo)
5046 pred_rpo = bb_rpo[pred];
5049 /* Record the RPO number of the last visited block that needs
5050 live information from this block. */
5051 last_rpo[rpo[i]] = pred_rpo;
5055 sbitmap_free (live[rpo[i]]);
5056 live[rpo[i]] = NULL;
5059 /* We can free all successors live bitmaps if all their
5060 predecessors have been visited already. */
5061 FOR_EACH_EDGE (e, ei, bb->succs)
5062 if (last_rpo[e->dest->index] == i
5063 && live[e->dest->index])
5065 sbitmap_free (live[e->dest->index]);
5066 live[e->dest->index] = NULL;
5071 XDELETEVEC (bb_rpo);
5072 XDELETEVEC (last_rpo);
5073 for (i = 0; i < last_basic_block + NUM_FIXED_BLOCKS; ++i)
5075 sbitmap_free (live[i]);
5078 return need_asserts;
5081 /* Create an ASSERT_EXPR for NAME and insert it in the location
5082 indicated by LOC. Return true if we made any edge insertions. */
5085 process_assert_insertions_for (tree name, assert_locus_t loc)
5087 /* Build the comparison expression NAME_i COMP_CODE VAL. */
5094 /* If we have X <=> X do not insert an assert expr for that. */
5095 if (loc->expr == loc->val)
5098 cond = build2 (loc->comp_code, boolean_type_node, loc->expr, loc->val);
5099 assert_stmt = build_assert_expr_for (cond, name);
5102 /* We have been asked to insert the assertion on an edge. This
5103 is used only by COND_EXPR and SWITCH_EXPR assertions. */
5104 gcc_checking_assert (gimple_code (gsi_stmt (loc->si)) == GIMPLE_COND
5105 || (gimple_code (gsi_stmt (loc->si))
5108 gsi_insert_on_edge (loc->e, assert_stmt);
5112 /* Otherwise, we can insert right after LOC->SI iff the
5113 statement must not be the last statement in the block. */
5114 stmt = gsi_stmt (loc->si);
5115 if (!stmt_ends_bb_p (stmt))
5117 gsi_insert_after (&loc->si, assert_stmt, GSI_SAME_STMT);
5121 /* If STMT must be the last statement in BB, we can only insert new
5122 assertions on the non-abnormal edge out of BB. Note that since
5123 STMT is not control flow, there may only be one non-abnormal edge
5125 FOR_EACH_EDGE (e, ei, loc->bb->succs)
5126 if (!(e->flags & EDGE_ABNORMAL))
5128 gsi_insert_on_edge (e, assert_stmt);
5136 /* Process all the insertions registered for every name N_i registered
5137 in NEED_ASSERT_FOR. The list of assertions to be inserted are
5138 found in ASSERTS_FOR[i]. */
5141 process_assert_insertions (void)
5145 bool update_edges_p = false;
5146 int num_asserts = 0;
5148 if (dump_file && (dump_flags & TDF_DETAILS))
5149 dump_all_asserts (dump_file);
5151 EXECUTE_IF_SET_IN_BITMAP (need_assert_for, 0, i, bi)
5153 assert_locus_t loc = asserts_for[i];
5158 assert_locus_t next = loc->next;
5159 update_edges_p |= process_assert_insertions_for (ssa_name (i), loc);
5167 gsi_commit_edge_inserts ();
5169 statistics_counter_event (cfun, "Number of ASSERT_EXPR expressions inserted",
5174 /* Traverse the flowgraph looking for conditional jumps to insert range
5175 expressions. These range expressions are meant to provide information
5176 to optimizations that need to reason in terms of value ranges. They
5177 will not be expanded into RTL. For instance, given:
5186 this pass will transform the code into:
5192 x = ASSERT_EXPR <x, x < y>
5197 y = ASSERT_EXPR <y, x <= y>
5201 The idea is that once copy and constant propagation have run, other
5202 optimizations will be able to determine what ranges of values can 'x'
5203 take in different paths of the code, simply by checking the reaching
5204 definition of 'x'. */
5207 insert_range_assertions (void)
5209 need_assert_for = BITMAP_ALLOC (NULL);
5210 asserts_for = XCNEWVEC (assert_locus_t, num_ssa_names);
5212 calculate_dominance_info (CDI_DOMINATORS);
5214 if (find_assert_locations ())
5216 process_assert_insertions ();
5217 update_ssa (TODO_update_ssa_no_phi);
5220 if (dump_file && (dump_flags & TDF_DETAILS))
5222 fprintf (dump_file, "\nSSA form after inserting ASSERT_EXPRs\n");
5223 dump_function_to_file (current_function_decl, dump_file, dump_flags);
5227 BITMAP_FREE (need_assert_for);
5230 /* Checks one ARRAY_REF in REF, located at LOCUS. Ignores flexible arrays
5231 and "struct" hacks. If VRP can determine that the
5232 array subscript is a constant, check if it is outside valid
5233 range. If the array subscript is a RANGE, warn if it is
5234 non-overlapping with valid range.
5235 IGNORE_OFF_BY_ONE is true if the ARRAY_REF is inside a ADDR_EXPR. */
5238 check_array_ref (location_t location, tree ref, bool ignore_off_by_one)
5240 value_range_t* vr = NULL;
5241 tree low_sub, up_sub;
5242 tree low_bound, up_bound, up_bound_p1;
5245 if (TREE_NO_WARNING (ref))
5248 low_sub = up_sub = TREE_OPERAND (ref, 1);
5249 up_bound = array_ref_up_bound (ref);
5251 /* Can not check flexible arrays. */
5253 || TREE_CODE (up_bound) != INTEGER_CST)
5256 /* Accesses to trailing arrays via pointers may access storage
5257 beyond the types array bounds. */
5258 base = get_base_address (ref);
5259 if (base && TREE_CODE (base) == MEM_REF)
5261 tree cref, next = NULL_TREE;
5263 if (TREE_CODE (TREE_OPERAND (ref, 0)) != COMPONENT_REF)
5266 cref = TREE_OPERAND (ref, 0);
5267 if (TREE_CODE (TREE_TYPE (TREE_OPERAND (cref, 0))) == RECORD_TYPE)
5268 for (next = DECL_CHAIN (TREE_OPERAND (cref, 1));
5269 next && TREE_CODE (next) != FIELD_DECL;
5270 next = DECL_CHAIN (next))
5273 /* If this is the last field in a struct type or a field in a
5274 union type do not warn. */
5279 low_bound = array_ref_low_bound (ref);
5280 up_bound_p1 = int_const_binop (PLUS_EXPR, up_bound, integer_one_node);
5282 if (TREE_CODE (low_sub) == SSA_NAME)
5284 vr = get_value_range (low_sub);
5285 if (vr->type == VR_RANGE || vr->type == VR_ANTI_RANGE)
5287 low_sub = vr->type == VR_RANGE ? vr->max : vr->min;
5288 up_sub = vr->type == VR_RANGE ? vr->min : vr->max;
5292 if (vr && vr->type == VR_ANTI_RANGE)
5294 if (TREE_CODE (up_sub) == INTEGER_CST
5295 && tree_int_cst_lt (up_bound, up_sub)
5296 && TREE_CODE (low_sub) == INTEGER_CST
5297 && tree_int_cst_lt (low_sub, low_bound))
5299 warning_at (location, OPT_Warray_bounds,
5300 "array subscript is outside array bounds");
5301 TREE_NO_WARNING (ref) = 1;
5304 else if (TREE_CODE (up_sub) == INTEGER_CST
5305 && (ignore_off_by_one
5306 ? (tree_int_cst_lt (up_bound, up_sub)
5307 && !tree_int_cst_equal (up_bound_p1, up_sub))
5308 : (tree_int_cst_lt (up_bound, up_sub)
5309 || tree_int_cst_equal (up_bound_p1, up_sub))))
5311 warning_at (location, OPT_Warray_bounds,
5312 "array subscript is above array bounds");
5313 TREE_NO_WARNING (ref) = 1;
5315 else if (TREE_CODE (low_sub) == INTEGER_CST
5316 && tree_int_cst_lt (low_sub, low_bound))
5318 warning_at (location, OPT_Warray_bounds,
5319 "array subscript is below array bounds");
5320 TREE_NO_WARNING (ref) = 1;
5324 /* Searches if the expr T, located at LOCATION computes
5325 address of an ARRAY_REF, and call check_array_ref on it. */
5328 search_for_addr_array (tree t, location_t location)
5330 while (TREE_CODE (t) == SSA_NAME)
5332 gimple g = SSA_NAME_DEF_STMT (t);
5334 if (gimple_code (g) != GIMPLE_ASSIGN)
5337 if (get_gimple_rhs_class (gimple_assign_rhs_code (g))
5338 != GIMPLE_SINGLE_RHS)
5341 t = gimple_assign_rhs1 (g);
5345 /* We are only interested in addresses of ARRAY_REF's. */
5346 if (TREE_CODE (t) != ADDR_EXPR)
5349 /* Check each ARRAY_REFs in the reference chain. */
5352 if (TREE_CODE (t) == ARRAY_REF)
5353 check_array_ref (location, t, true /*ignore_off_by_one*/);
5355 t = TREE_OPERAND (t, 0);
5357 while (handled_component_p (t));
5359 if (TREE_CODE (t) == MEM_REF
5360 && TREE_CODE (TREE_OPERAND (t, 0)) == ADDR_EXPR
5361 && !TREE_NO_WARNING (t))
5363 tree tem = TREE_OPERAND (TREE_OPERAND (t, 0), 0);
5364 tree low_bound, up_bound, el_sz;
5366 if (TREE_CODE (TREE_TYPE (tem)) != ARRAY_TYPE
5367 || TREE_CODE (TREE_TYPE (TREE_TYPE (tem))) == ARRAY_TYPE
5368 || !TYPE_DOMAIN (TREE_TYPE (tem)))
5371 low_bound = TYPE_MIN_VALUE (TYPE_DOMAIN (TREE_TYPE (tem)));
5372 up_bound = TYPE_MAX_VALUE (TYPE_DOMAIN (TREE_TYPE (tem)));
5373 el_sz = TYPE_SIZE_UNIT (TREE_TYPE (TREE_TYPE (tem)));
5375 || TREE_CODE (low_bound) != INTEGER_CST
5377 || TREE_CODE (up_bound) != INTEGER_CST
5379 || TREE_CODE (el_sz) != INTEGER_CST)
5382 idx = mem_ref_offset (t);
5383 idx = double_int_sdiv (idx, tree_to_double_int (el_sz), TRUNC_DIV_EXPR);
5384 if (double_int_scmp (idx, double_int_zero) < 0)
5386 warning_at (location, OPT_Warray_bounds,
5387 "array subscript is below array bounds");
5388 TREE_NO_WARNING (t) = 1;
5390 else if (double_int_scmp (idx,
5393 (tree_to_double_int (up_bound),
5395 (tree_to_double_int (low_bound))),
5396 double_int_one)) > 0)
5398 warning_at (location, OPT_Warray_bounds,
5399 "array subscript is above array bounds");
5400 TREE_NO_WARNING (t) = 1;
5405 /* walk_tree() callback that checks if *TP is
5406 an ARRAY_REF inside an ADDR_EXPR (in which an array
5407 subscript one outside the valid range is allowed). Call
5408 check_array_ref for each ARRAY_REF found. The location is
5412 check_array_bounds (tree *tp, int *walk_subtree, void *data)
5415 struct walk_stmt_info *wi = (struct walk_stmt_info *) data;
5416 location_t location;
5418 if (EXPR_HAS_LOCATION (t))
5419 location = EXPR_LOCATION (t);
5422 location_t *locp = (location_t *) wi->info;
5426 *walk_subtree = TRUE;
5428 if (TREE_CODE (t) == ARRAY_REF)
5429 check_array_ref (location, t, false /*ignore_off_by_one*/);
5431 if (TREE_CODE (t) == MEM_REF
5432 || (TREE_CODE (t) == RETURN_EXPR && TREE_OPERAND (t, 0)))
5433 search_for_addr_array (TREE_OPERAND (t, 0), location);
5435 if (TREE_CODE (t) == ADDR_EXPR)
5436 *walk_subtree = FALSE;
5441 /* Walk over all statements of all reachable BBs and call check_array_bounds
5445 check_all_array_refs (void)
5448 gimple_stmt_iterator si;
5454 bool executable = false;
5456 /* Skip blocks that were found to be unreachable. */
5457 FOR_EACH_EDGE (e, ei, bb->preds)
5458 executable |= !!(e->flags & EDGE_EXECUTABLE);
5462 for (si = gsi_start_bb (bb); !gsi_end_p (si); gsi_next (&si))
5464 gimple stmt = gsi_stmt (si);
5465 struct walk_stmt_info wi;
5466 if (!gimple_has_location (stmt))
5469 if (is_gimple_call (stmt))
5472 size_t n = gimple_call_num_args (stmt);
5473 for (i = 0; i < n; i++)
5475 tree arg = gimple_call_arg (stmt, i);
5476 search_for_addr_array (arg, gimple_location (stmt));
5481 memset (&wi, 0, sizeof (wi));
5482 wi.info = CONST_CAST (void *, (const void *)
5483 gimple_location_ptr (stmt));
5485 walk_gimple_op (gsi_stmt (si),
5493 /* Convert range assertion expressions into the implied copies and
5494 copy propagate away the copies. Doing the trivial copy propagation
5495 here avoids the need to run the full copy propagation pass after
5498 FIXME, this will eventually lead to copy propagation removing the
5499 names that had useful range information attached to them. For
5500 instance, if we had the assertion N_i = ASSERT_EXPR <N_j, N_j > 3>,
5501 then N_i will have the range [3, +INF].
5503 However, by converting the assertion into the implied copy
5504 operation N_i = N_j, we will then copy-propagate N_j into the uses
5505 of N_i and lose the range information. We may want to hold on to
5506 ASSERT_EXPRs a little while longer as the ranges could be used in
5507 things like jump threading.
5509 The problem with keeping ASSERT_EXPRs around is that passes after
5510 VRP need to handle them appropriately.
5512 Another approach would be to make the range information a first
5513 class property of the SSA_NAME so that it can be queried from
5514 any pass. This is made somewhat more complex by the need for
5515 multiple ranges to be associated with one SSA_NAME. */
5518 remove_range_assertions (void)
5521 gimple_stmt_iterator si;
5523 /* Note that the BSI iterator bump happens at the bottom of the
5524 loop and no bump is necessary if we're removing the statement
5525 referenced by the current BSI. */
5527 for (si = gsi_start_bb (bb); !gsi_end_p (si);)
5529 gimple stmt = gsi_stmt (si);
5532 if (is_gimple_assign (stmt)
5533 && gimple_assign_rhs_code (stmt) == ASSERT_EXPR)
5535 tree rhs = gimple_assign_rhs1 (stmt);
5537 tree cond = fold (ASSERT_EXPR_COND (rhs));
5538 use_operand_p use_p;
5539 imm_use_iterator iter;
5541 gcc_assert (cond != boolean_false_node);
5543 /* Propagate the RHS into every use of the LHS. */
5544 var = ASSERT_EXPR_VAR (rhs);
5545 FOR_EACH_IMM_USE_STMT (use_stmt, iter,
5546 gimple_assign_lhs (stmt))
5547 FOR_EACH_IMM_USE_ON_STMT (use_p, iter)
5549 SET_USE (use_p, var);
5550 gcc_assert (TREE_CODE (var) == SSA_NAME);
5553 /* And finally, remove the copy, it is not needed. */
5554 gsi_remove (&si, true);
5555 release_defs (stmt);
5563 /* Return true if STMT is interesting for VRP. */
5566 stmt_interesting_for_vrp (gimple stmt)
5568 if (gimple_code (stmt) == GIMPLE_PHI
5569 && is_gimple_reg (gimple_phi_result (stmt))
5570 && (INTEGRAL_TYPE_P (TREE_TYPE (gimple_phi_result (stmt)))
5571 || POINTER_TYPE_P (TREE_TYPE (gimple_phi_result (stmt)))))
5573 else if (is_gimple_assign (stmt) || is_gimple_call (stmt))
5575 tree lhs = gimple_get_lhs (stmt);
5577 /* In general, assignments with virtual operands are not useful
5578 for deriving ranges, with the obvious exception of calls to
5579 builtin functions. */
5580 if (lhs && TREE_CODE (lhs) == SSA_NAME
5581 && (INTEGRAL_TYPE_P (TREE_TYPE (lhs))
5582 || POINTER_TYPE_P (TREE_TYPE (lhs)))
5583 && ((is_gimple_call (stmt)
5584 && gimple_call_fndecl (stmt) != NULL_TREE
5585 && DECL_BUILT_IN (gimple_call_fndecl (stmt)))
5586 || !gimple_vuse (stmt)))
5589 else if (gimple_code (stmt) == GIMPLE_COND
5590 || gimple_code (stmt) == GIMPLE_SWITCH)
5597 /* Initialize local data structures for VRP. */
5600 vrp_initialize (void)
5604 values_propagated = false;
5605 num_vr_values = num_ssa_names;
5606 vr_value = XCNEWVEC (value_range_t *, num_vr_values);
5607 vr_phi_edge_counts = XCNEWVEC (int, num_ssa_names);
5611 gimple_stmt_iterator si;
5613 for (si = gsi_start_phis (bb); !gsi_end_p (si); gsi_next (&si))
5615 gimple phi = gsi_stmt (si);
5616 if (!stmt_interesting_for_vrp (phi))
5618 tree lhs = PHI_RESULT (phi);
5619 set_value_range_to_varying (get_value_range (lhs));
5620 prop_set_simulate_again (phi, false);
5623 prop_set_simulate_again (phi, true);
5626 for (si = gsi_start_bb (bb); !gsi_end_p (si); gsi_next (&si))
5628 gimple stmt = gsi_stmt (si);
5630 /* If the statement is a control insn, then we do not
5631 want to avoid simulating the statement once. Failure
5632 to do so means that those edges will never get added. */
5633 if (stmt_ends_bb_p (stmt))
5634 prop_set_simulate_again (stmt, true);
5635 else if (!stmt_interesting_for_vrp (stmt))
5639 FOR_EACH_SSA_TREE_OPERAND (def, stmt, i, SSA_OP_DEF)
5640 set_value_range_to_varying (get_value_range (def));
5641 prop_set_simulate_again (stmt, false);
5644 prop_set_simulate_again (stmt, true);
5649 /* Return the singleton value-range for NAME or NAME. */
5652 vrp_valueize (tree name)
5654 if (TREE_CODE (name) == SSA_NAME)
5656 value_range_t *vr = get_value_range (name);
5657 if (vr->type == VR_RANGE
5658 && (vr->min == vr->max
5659 || operand_equal_p (vr->min, vr->max, 0)))
5665 /* Visit assignment STMT. If it produces an interesting range, record
5666 the SSA name in *OUTPUT_P. */
5668 static enum ssa_prop_result
5669 vrp_visit_assignment_or_call (gimple stmt, tree *output_p)
5673 enum gimple_code code = gimple_code (stmt);
5674 lhs = gimple_get_lhs (stmt);
5676 /* We only keep track of ranges in integral and pointer types. */
5677 if (TREE_CODE (lhs) == SSA_NAME
5678 && ((INTEGRAL_TYPE_P (TREE_TYPE (lhs))
5679 /* It is valid to have NULL MIN/MAX values on a type. See
5680 build_range_type. */
5681 && TYPE_MIN_VALUE (TREE_TYPE (lhs))
5682 && TYPE_MAX_VALUE (TREE_TYPE (lhs)))
5683 || POINTER_TYPE_P (TREE_TYPE (lhs))))
5685 value_range_t new_vr = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
5687 /* Try folding the statement to a constant first. */
5688 tree tem = gimple_fold_stmt_to_constant (stmt, vrp_valueize);
5689 if (tem && !is_overflow_infinity (tem))
5690 set_value_range (&new_vr, VR_RANGE, tem, tem, NULL);
5691 /* Then dispatch to value-range extracting functions. */
5692 else if (code == GIMPLE_CALL)
5693 extract_range_basic (&new_vr, stmt);
5695 extract_range_from_assignment (&new_vr, stmt);
5697 if (update_value_range (lhs, &new_vr))
5701 if (dump_file && (dump_flags & TDF_DETAILS))
5703 fprintf (dump_file, "Found new range for ");
5704 print_generic_expr (dump_file, lhs, 0);
5705 fprintf (dump_file, ": ");
5706 dump_value_range (dump_file, &new_vr);
5707 fprintf (dump_file, "\n\n");
5710 if (new_vr.type == VR_VARYING)
5711 return SSA_PROP_VARYING;
5713 return SSA_PROP_INTERESTING;
5716 return SSA_PROP_NOT_INTERESTING;
5719 /* Every other statement produces no useful ranges. */
5720 FOR_EACH_SSA_TREE_OPERAND (def, stmt, iter, SSA_OP_DEF)
5721 set_value_range_to_varying (get_value_range (def));
5723 return SSA_PROP_VARYING;
5726 /* Helper that gets the value range of the SSA_NAME with version I
5727 or a symbolic range containing the SSA_NAME only if the value range
5728 is varying or undefined. */
5730 static inline value_range_t
5731 get_vr_for_comparison (int i)
5733 value_range_t vr = *get_value_range (ssa_name (i));
5735 /* If name N_i does not have a valid range, use N_i as its own
5736 range. This allows us to compare against names that may
5737 have N_i in their ranges. */
5738 if (vr.type == VR_VARYING || vr.type == VR_UNDEFINED)
5741 vr.min = ssa_name (i);
5742 vr.max = ssa_name (i);
5748 /* Compare all the value ranges for names equivalent to VAR with VAL
5749 using comparison code COMP. Return the same value returned by
5750 compare_range_with_value, including the setting of
5751 *STRICT_OVERFLOW_P. */
5754 compare_name_with_value (enum tree_code comp, tree var, tree val,
5755 bool *strict_overflow_p)
5761 int used_strict_overflow;
5763 value_range_t equiv_vr;
5765 /* Get the set of equivalences for VAR. */
5766 e = get_value_range (var)->equiv;
5768 /* Start at -1. Set it to 0 if we do a comparison without relying
5769 on overflow, or 1 if all comparisons rely on overflow. */
5770 used_strict_overflow = -1;
5772 /* Compare vars' value range with val. */
5773 equiv_vr = get_vr_for_comparison (SSA_NAME_VERSION (var));
5775 retval = compare_range_with_value (comp, &equiv_vr, val, &sop);
5777 used_strict_overflow = sop ? 1 : 0;
5779 /* If the equiv set is empty we have done all work we need to do. */
5783 && used_strict_overflow > 0)
5784 *strict_overflow_p = true;
5788 EXECUTE_IF_SET_IN_BITMAP (e, 0, i, bi)
5790 equiv_vr = get_vr_for_comparison (i);
5792 t = compare_range_with_value (comp, &equiv_vr, val, &sop);
5795 /* If we get different answers from different members
5796 of the equivalence set this check must be in a dead
5797 code region. Folding it to a trap representation
5798 would be correct here. For now just return don't-know. */
5808 used_strict_overflow = 0;
5809 else if (used_strict_overflow < 0)
5810 used_strict_overflow = 1;
5815 && used_strict_overflow > 0)
5816 *strict_overflow_p = true;
5822 /* Given a comparison code COMP and names N1 and N2, compare all the
5823 ranges equivalent to N1 against all the ranges equivalent to N2
5824 to determine the value of N1 COMP N2. Return the same value
5825 returned by compare_ranges. Set *STRICT_OVERFLOW_P to indicate
5826 whether we relied on an overflow infinity in the comparison. */
5830 compare_names (enum tree_code comp, tree n1, tree n2,
5831 bool *strict_overflow_p)
5835 bitmap_iterator bi1, bi2;
5837 int used_strict_overflow;
5838 static bitmap_obstack *s_obstack = NULL;
5839 static bitmap s_e1 = NULL, s_e2 = NULL;
5841 /* Compare the ranges of every name equivalent to N1 against the
5842 ranges of every name equivalent to N2. */
5843 e1 = get_value_range (n1)->equiv;
5844 e2 = get_value_range (n2)->equiv;
5846 /* Use the fake bitmaps if e1 or e2 are not available. */
5847 if (s_obstack == NULL)
5849 s_obstack = XNEW (bitmap_obstack);
5850 bitmap_obstack_initialize (s_obstack);
5851 s_e1 = BITMAP_ALLOC (s_obstack);
5852 s_e2 = BITMAP_ALLOC (s_obstack);
5859 /* Add N1 and N2 to their own set of equivalences to avoid
5860 duplicating the body of the loop just to check N1 and N2
5862 bitmap_set_bit (e1, SSA_NAME_VERSION (n1));
5863 bitmap_set_bit (e2, SSA_NAME_VERSION (n2));
5865 /* If the equivalence sets have a common intersection, then the two
5866 names can be compared without checking their ranges. */
5867 if (bitmap_intersect_p (e1, e2))
5869 bitmap_clear_bit (e1, SSA_NAME_VERSION (n1));
5870 bitmap_clear_bit (e2, SSA_NAME_VERSION (n2));
5872 return (comp == EQ_EXPR || comp == GE_EXPR || comp == LE_EXPR)
5874 : boolean_false_node;
5877 /* Start at -1. Set it to 0 if we do a comparison without relying
5878 on overflow, or 1 if all comparisons rely on overflow. */
5879 used_strict_overflow = -1;
5881 /* Otherwise, compare all the equivalent ranges. First, add N1 and
5882 N2 to their own set of equivalences to avoid duplicating the body
5883 of the loop just to check N1 and N2 ranges. */
5884 EXECUTE_IF_SET_IN_BITMAP (e1, 0, i1, bi1)
5886 value_range_t vr1 = get_vr_for_comparison (i1);
5888 t = retval = NULL_TREE;
5889 EXECUTE_IF_SET_IN_BITMAP (e2, 0, i2, bi2)
5893 value_range_t vr2 = get_vr_for_comparison (i2);
5895 t = compare_ranges (comp, &vr1, &vr2, &sop);
5898 /* If we get different answers from different members
5899 of the equivalence set this check must be in a dead
5900 code region. Folding it to a trap representation
5901 would be correct here. For now just return don't-know. */
5905 bitmap_clear_bit (e1, SSA_NAME_VERSION (n1));
5906 bitmap_clear_bit (e2, SSA_NAME_VERSION (n2));
5912 used_strict_overflow = 0;
5913 else if (used_strict_overflow < 0)
5914 used_strict_overflow = 1;
5920 bitmap_clear_bit (e1, SSA_NAME_VERSION (n1));
5921 bitmap_clear_bit (e2, SSA_NAME_VERSION (n2));
5922 if (used_strict_overflow > 0)
5923 *strict_overflow_p = true;
5928 /* None of the equivalent ranges are useful in computing this
5930 bitmap_clear_bit (e1, SSA_NAME_VERSION (n1));
5931 bitmap_clear_bit (e2, SSA_NAME_VERSION (n2));
5935 /* Helper function for vrp_evaluate_conditional_warnv. */
5938 vrp_evaluate_conditional_warnv_with_ops_using_ranges (enum tree_code code,
5940 bool * strict_overflow_p)
5942 value_range_t *vr0, *vr1;
5944 vr0 = (TREE_CODE (op0) == SSA_NAME) ? get_value_range (op0) : NULL;
5945 vr1 = (TREE_CODE (op1) == SSA_NAME) ? get_value_range (op1) : NULL;
5948 return compare_ranges (code, vr0, vr1, strict_overflow_p);
5949 else if (vr0 && vr1 == NULL)
5950 return compare_range_with_value (code, vr0, op1, strict_overflow_p);
5951 else if (vr0 == NULL && vr1)
5952 return (compare_range_with_value
5953 (swap_tree_comparison (code), vr1, op0, strict_overflow_p));
5957 /* Helper function for vrp_evaluate_conditional_warnv. */
5960 vrp_evaluate_conditional_warnv_with_ops (enum tree_code code, tree op0,
5961 tree op1, bool use_equiv_p,
5962 bool *strict_overflow_p, bool *only_ranges)
5966 *only_ranges = true;
5968 /* We only deal with integral and pointer types. */
5969 if (!INTEGRAL_TYPE_P (TREE_TYPE (op0))
5970 && !POINTER_TYPE_P (TREE_TYPE (op0)))
5976 && (ret = vrp_evaluate_conditional_warnv_with_ops_using_ranges
5977 (code, op0, op1, strict_overflow_p)))
5979 *only_ranges = false;
5980 if (TREE_CODE (op0) == SSA_NAME && TREE_CODE (op1) == SSA_NAME)
5981 return compare_names (code, op0, op1, strict_overflow_p);
5982 else if (TREE_CODE (op0) == SSA_NAME)
5983 return compare_name_with_value (code, op0, op1, strict_overflow_p);
5984 else if (TREE_CODE (op1) == SSA_NAME)
5985 return (compare_name_with_value
5986 (swap_tree_comparison (code), op1, op0, strict_overflow_p));
5989 return vrp_evaluate_conditional_warnv_with_ops_using_ranges (code, op0, op1,
5994 /* Given (CODE OP0 OP1) within STMT, try to simplify it based on value range
5995 information. Return NULL if the conditional can not be evaluated.
5996 The ranges of all the names equivalent with the operands in COND
5997 will be used when trying to compute the value. If the result is
5998 based on undefined signed overflow, issue a warning if
6002 vrp_evaluate_conditional (enum tree_code code, tree op0, tree op1, gimple stmt)
6008 /* Some passes and foldings leak constants with overflow flag set
6009 into the IL. Avoid doing wrong things with these and bail out. */
6010 if ((TREE_CODE (op0) == INTEGER_CST
6011 && TREE_OVERFLOW (op0))
6012 || (TREE_CODE (op1) == INTEGER_CST
6013 && TREE_OVERFLOW (op1)))
6017 ret = vrp_evaluate_conditional_warnv_with_ops (code, op0, op1, true, &sop,
6022 enum warn_strict_overflow_code wc;
6023 const char* warnmsg;
6025 if (is_gimple_min_invariant (ret))
6027 wc = WARN_STRICT_OVERFLOW_CONDITIONAL;
6028 warnmsg = G_("assuming signed overflow does not occur when "
6029 "simplifying conditional to constant");
6033 wc = WARN_STRICT_OVERFLOW_COMPARISON;
6034 warnmsg = G_("assuming signed overflow does not occur when "
6035 "simplifying conditional");
6038 if (issue_strict_overflow_warning (wc))
6040 location_t location;
6042 if (!gimple_has_location (stmt))
6043 location = input_location;
6045 location = gimple_location (stmt);
6046 warning_at (location, OPT_Wstrict_overflow, "%s", warnmsg);
6050 if (warn_type_limits
6051 && ret && only_ranges
6052 && TREE_CODE_CLASS (code) == tcc_comparison
6053 && TREE_CODE (op0) == SSA_NAME)
6055 /* If the comparison is being folded and the operand on the LHS
6056 is being compared against a constant value that is outside of
6057 the natural range of OP0's type, then the predicate will
6058 always fold regardless of the value of OP0. If -Wtype-limits
6059 was specified, emit a warning. */
6060 tree type = TREE_TYPE (op0);
6061 value_range_t *vr0 = get_value_range (op0);
6063 if (vr0->type != VR_VARYING
6064 && INTEGRAL_TYPE_P (type)
6065 && vrp_val_is_min (vr0->min)
6066 && vrp_val_is_max (vr0->max)
6067 && is_gimple_min_invariant (op1))
6069 location_t location;
6071 if (!gimple_has_location (stmt))
6072 location = input_location;
6074 location = gimple_location (stmt);
6076 warning_at (location, OPT_Wtype_limits,
6078 ? G_("comparison always false "
6079 "due to limited range of data type")
6080 : G_("comparison always true "
6081 "due to limited range of data type"));
6089 /* Visit conditional statement STMT. If we can determine which edge
6090 will be taken out of STMT's basic block, record it in
6091 *TAKEN_EDGE_P and return SSA_PROP_INTERESTING. Otherwise, return
6092 SSA_PROP_VARYING. */
6094 static enum ssa_prop_result
6095 vrp_visit_cond_stmt (gimple stmt, edge *taken_edge_p)
6100 *taken_edge_p = NULL;
6102 if (dump_file && (dump_flags & TDF_DETAILS))
6107 fprintf (dump_file, "\nVisiting conditional with predicate: ");
6108 print_gimple_stmt (dump_file, stmt, 0, 0);
6109 fprintf (dump_file, "\nWith known ranges\n");
6111 FOR_EACH_SSA_TREE_OPERAND (use, stmt, i, SSA_OP_USE)
6113 fprintf (dump_file, "\t");
6114 print_generic_expr (dump_file, use, 0);
6115 fprintf (dump_file, ": ");
6116 dump_value_range (dump_file, vr_value[SSA_NAME_VERSION (use)]);
6119 fprintf (dump_file, "\n");
6122 /* Compute the value of the predicate COND by checking the known
6123 ranges of each of its operands.
6125 Note that we cannot evaluate all the equivalent ranges here
6126 because those ranges may not yet be final and with the current
6127 propagation strategy, we cannot determine when the value ranges
6128 of the names in the equivalence set have changed.
6130 For instance, given the following code fragment
6134 i_14 = ASSERT_EXPR <i_5, i_5 != 0>
6138 Assume that on the first visit to i_14, i_5 has the temporary
6139 range [8, 8] because the second argument to the PHI function is
6140 not yet executable. We derive the range ~[0, 0] for i_14 and the
6141 equivalence set { i_5 }. So, when we visit 'if (i_14 == 1)' for
6142 the first time, since i_14 is equivalent to the range [8, 8], we
6143 determine that the predicate is always false.
6145 On the next round of propagation, i_13 is determined to be
6146 VARYING, which causes i_5 to drop down to VARYING. So, another
6147 visit to i_14 is scheduled. In this second visit, we compute the
6148 exact same range and equivalence set for i_14, namely ~[0, 0] and
6149 { i_5 }. But we did not have the previous range for i_5
6150 registered, so vrp_visit_assignment thinks that the range for
6151 i_14 has not changed. Therefore, the predicate 'if (i_14 == 1)'
6152 is not visited again, which stops propagation from visiting
6153 statements in the THEN clause of that if().
6155 To properly fix this we would need to keep the previous range
6156 value for the names in the equivalence set. This way we would've
6157 discovered that from one visit to the other i_5 changed from
6158 range [8, 8] to VR_VARYING.
6160 However, fixing this apparent limitation may not be worth the
6161 additional checking. Testing on several code bases (GCC, DLV,
6162 MICO, TRAMP3D and SPEC2000) showed that doing this results in
6163 4 more predicates folded in SPEC. */
6166 val = vrp_evaluate_conditional_warnv_with_ops (gimple_cond_code (stmt),
6167 gimple_cond_lhs (stmt),
6168 gimple_cond_rhs (stmt),
6173 *taken_edge_p = find_taken_edge (gimple_bb (stmt), val);
6176 if (dump_file && (dump_flags & TDF_DETAILS))
6178 "\nIgnoring predicate evaluation because "
6179 "it assumes that signed overflow is undefined");
6184 if (dump_file && (dump_flags & TDF_DETAILS))
6186 fprintf (dump_file, "\nPredicate evaluates to: ");
6187 if (val == NULL_TREE)
6188 fprintf (dump_file, "DON'T KNOW\n");
6190 print_generic_stmt (dump_file, val, 0);
6193 return (*taken_edge_p) ? SSA_PROP_INTERESTING : SSA_PROP_VARYING;
6196 /* Searches the case label vector VEC for the index *IDX of the CASE_LABEL
6197 that includes the value VAL. The search is restricted to the range
6198 [START_IDX, n - 1] where n is the size of VEC.
6200 If there is a CASE_LABEL for VAL, its index is placed in IDX and true is
6203 If there is no CASE_LABEL for VAL and there is one that is larger than VAL,
6204 it is placed in IDX and false is returned.
6206 If VAL is larger than any CASE_LABEL, n is placed on IDX and false is
6210 find_case_label_index (gimple stmt, size_t start_idx, tree val, size_t *idx)
6212 size_t n = gimple_switch_num_labels (stmt);
6215 /* Find case label for minimum of the value range or the next one.
6216 At each iteration we are searching in [low, high - 1]. */
6218 for (low = start_idx, high = n; high != low; )
6222 /* Note that i != high, so we never ask for n. */
6223 size_t i = (high + low) / 2;
6224 t = gimple_switch_label (stmt, i);
6226 /* Cache the result of comparing CASE_LOW and val. */
6227 cmp = tree_int_cst_compare (CASE_LOW (t), val);
6231 /* Ranges cannot be empty. */
6240 if (CASE_HIGH (t) != NULL
6241 && tree_int_cst_compare (CASE_HIGH (t), val) >= 0)
6253 /* Searches the case label vector VEC for the range of CASE_LABELs that is used
6254 for values between MIN and MAX. The first index is placed in MIN_IDX. The
6255 last index is placed in MAX_IDX. If the range of CASE_LABELs is empty
6256 then MAX_IDX < MIN_IDX.
6257 Returns true if the default label is not needed. */
6260 find_case_label_range (gimple stmt, tree min, tree max, size_t *min_idx,
6264 bool min_take_default = !find_case_label_index (stmt, 1, min, &i);
6265 bool max_take_default = !find_case_label_index (stmt, i, max, &j);
6269 && max_take_default)
6271 /* Only the default case label reached.
6272 Return an empty range. */
6279 bool take_default = min_take_default || max_take_default;
6283 if (max_take_default)
6286 /* If the case label range is continuous, we do not need
6287 the default case label. Verify that. */
6288 high = CASE_LOW (gimple_switch_label (stmt, i));
6289 if (CASE_HIGH (gimple_switch_label (stmt, i)))
6290 high = CASE_HIGH (gimple_switch_label (stmt, i));
6291 for (k = i + 1; k <= j; ++k)
6293 low = CASE_LOW (gimple_switch_label (stmt, k));
6294 if (!integer_onep (int_const_binop (MINUS_EXPR, low, high)))
6296 take_default = true;
6300 if (CASE_HIGH (gimple_switch_label (stmt, k)))
6301 high = CASE_HIGH (gimple_switch_label (stmt, k));
6306 return !take_default;
6310 /* Visit switch statement STMT. If we can determine which edge
6311 will be taken out of STMT's basic block, record it in
6312 *TAKEN_EDGE_P and return SSA_PROP_INTERESTING. Otherwise, return
6313 SSA_PROP_VARYING. */
6315 static enum ssa_prop_result
6316 vrp_visit_switch_stmt (gimple stmt, edge *taken_edge_p)
6320 size_t i = 0, j = 0;
6323 *taken_edge_p = NULL;
6324 op = gimple_switch_index (stmt);
6325 if (TREE_CODE (op) != SSA_NAME)
6326 return SSA_PROP_VARYING;
6328 vr = get_value_range (op);
6329 if (dump_file && (dump_flags & TDF_DETAILS))
6331 fprintf (dump_file, "\nVisiting switch expression with operand ");
6332 print_generic_expr (dump_file, op, 0);
6333 fprintf (dump_file, " with known range ");
6334 dump_value_range (dump_file, vr);
6335 fprintf (dump_file, "\n");
6338 if (vr->type != VR_RANGE
6339 || symbolic_range_p (vr))
6340 return SSA_PROP_VARYING;
6342 /* Find the single edge that is taken from the switch expression. */
6343 take_default = !find_case_label_range (stmt, vr->min, vr->max, &i, &j);
6345 /* Check if the range spans no CASE_LABEL. If so, we only reach the default
6349 gcc_assert (take_default);
6350 val = gimple_switch_default_label (stmt);
6354 /* Check if labels with index i to j and maybe the default label
6355 are all reaching the same label. */
6357 val = gimple_switch_label (stmt, i);
6359 && CASE_LABEL (gimple_switch_default_label (stmt))
6360 != CASE_LABEL (val))
6362 if (dump_file && (dump_flags & TDF_DETAILS))
6363 fprintf (dump_file, " not a single destination for this "
6365 return SSA_PROP_VARYING;
6367 for (++i; i <= j; ++i)
6369 if (CASE_LABEL (gimple_switch_label (stmt, i)) != CASE_LABEL (val))
6371 if (dump_file && (dump_flags & TDF_DETAILS))
6372 fprintf (dump_file, " not a single destination for this "
6374 return SSA_PROP_VARYING;
6379 *taken_edge_p = find_edge (gimple_bb (stmt),
6380 label_to_block (CASE_LABEL (val)));
6382 if (dump_file && (dump_flags & TDF_DETAILS))
6384 fprintf (dump_file, " will take edge to ");
6385 print_generic_stmt (dump_file, CASE_LABEL (val), 0);
6388 return SSA_PROP_INTERESTING;
6392 /* Evaluate statement STMT. If the statement produces a useful range,
6393 return SSA_PROP_INTERESTING and record the SSA name with the
6394 interesting range into *OUTPUT_P.
6396 If STMT is a conditional branch and we can determine its truth
6397 value, the taken edge is recorded in *TAKEN_EDGE_P.
6399 If STMT produces a varying value, return SSA_PROP_VARYING. */
6401 static enum ssa_prop_result
6402 vrp_visit_stmt (gimple stmt, edge *taken_edge_p, tree *output_p)
6407 if (dump_file && (dump_flags & TDF_DETAILS))
6409 fprintf (dump_file, "\nVisiting statement:\n");
6410 print_gimple_stmt (dump_file, stmt, 0, dump_flags);
6411 fprintf (dump_file, "\n");
6414 if (!stmt_interesting_for_vrp (stmt))
6415 gcc_assert (stmt_ends_bb_p (stmt));
6416 else if (is_gimple_assign (stmt) || is_gimple_call (stmt))
6418 /* In general, assignments with virtual operands are not useful
6419 for deriving ranges, with the obvious exception of calls to
6420 builtin functions. */
6421 if ((is_gimple_call (stmt)
6422 && gimple_call_fndecl (stmt) != NULL_TREE
6423 && DECL_BUILT_IN (gimple_call_fndecl (stmt)))
6424 || !gimple_vuse (stmt))
6425 return vrp_visit_assignment_or_call (stmt, output_p);
6427 else if (gimple_code (stmt) == GIMPLE_COND)
6428 return vrp_visit_cond_stmt (stmt, taken_edge_p);
6429 else if (gimple_code (stmt) == GIMPLE_SWITCH)
6430 return vrp_visit_switch_stmt (stmt, taken_edge_p);
6432 /* All other statements produce nothing of interest for VRP, so mark
6433 their outputs varying and prevent further simulation. */
6434 FOR_EACH_SSA_TREE_OPERAND (def, stmt, iter, SSA_OP_DEF)
6435 set_value_range_to_varying (get_value_range (def));
6437 return SSA_PROP_VARYING;
6441 /* Meet operation for value ranges. Given two value ranges VR0 and
6442 VR1, store in VR0 a range that contains both VR0 and VR1. This
6443 may not be the smallest possible such range. */
6446 vrp_meet (value_range_t *vr0, value_range_t *vr1)
6448 if (vr0->type == VR_UNDEFINED)
6450 /* Drop equivalences. See PR53465. */
6451 set_value_range (vr0, vr1->type, vr1->min, vr1->max, NULL);
6455 if (vr1->type == VR_UNDEFINED)
6457 /* VR0 already has the resulting range, just drop equivalences.
6460 bitmap_clear (vr0->equiv);
6464 if (vr0->type == VR_VARYING)
6466 /* Nothing to do. VR0 already has the resulting range. */
6470 if (vr1->type == VR_VARYING)
6472 set_value_range_to_varying (vr0);
6476 if (vr0->type == VR_RANGE && vr1->type == VR_RANGE)
6481 /* Compute the convex hull of the ranges. The lower limit of
6482 the new range is the minimum of the two ranges. If they
6483 cannot be compared, then give up. */
6484 cmp = compare_values (vr0->min, vr1->min);
6485 if (cmp == 0 || cmp == 1)
6492 /* Similarly, the upper limit of the new range is the maximum
6493 of the two ranges. If they cannot be compared, then
6495 cmp = compare_values (vr0->max, vr1->max);
6496 if (cmp == 0 || cmp == -1)
6503 /* Check for useless ranges. */
6504 if (INTEGRAL_TYPE_P (TREE_TYPE (min))
6505 && ((vrp_val_is_min (min) || is_overflow_infinity (min))
6506 && (vrp_val_is_max (max) || is_overflow_infinity (max))))
6509 /* The resulting set of equivalences is the intersection of
6511 if (vr0->equiv && vr1->equiv && vr0->equiv != vr1->equiv)
6512 bitmap_and_into (vr0->equiv, vr1->equiv);
6513 else if (vr0->equiv && !vr1->equiv)
6514 bitmap_clear (vr0->equiv);
6516 set_value_range (vr0, vr0->type, min, max, vr0->equiv);
6518 else if (vr0->type == VR_ANTI_RANGE && vr1->type == VR_ANTI_RANGE)
6520 /* Two anti-ranges meet only if their complements intersect.
6521 Only handle the case of identical ranges. */
6522 if (compare_values (vr0->min, vr1->min) == 0
6523 && compare_values (vr0->max, vr1->max) == 0
6524 && compare_values (vr0->min, vr0->max) == 0)
6526 /* The resulting set of equivalences is the intersection of
6528 if (vr0->equiv && vr1->equiv && vr0->equiv != vr1->equiv)
6529 bitmap_and_into (vr0->equiv, vr1->equiv);
6530 else if (vr0->equiv && !vr1->equiv)
6531 bitmap_clear (vr0->equiv);
6536 else if (vr0->type == VR_ANTI_RANGE || vr1->type == VR_ANTI_RANGE)
6538 /* For a numeric range [VAL1, VAL2] and an anti-range ~[VAL3, VAL4],
6539 only handle the case where the ranges have an empty intersection.
6540 The result of the meet operation is the anti-range. */
6541 if (!symbolic_range_p (vr0)
6542 && !symbolic_range_p (vr1)
6543 && !value_ranges_intersect_p (vr0, vr1))
6545 /* Copy most of VR1 into VR0. Don't copy VR1's equivalence
6546 set. We need to compute the intersection of the two
6547 equivalence sets. */
6548 if (vr1->type == VR_ANTI_RANGE)
6549 set_value_range (vr0, vr1->type, vr1->min, vr1->max, vr0->equiv);
6551 /* The resulting set of equivalences is the intersection of
6553 if (vr0->equiv && vr1->equiv && vr0->equiv != vr1->equiv)
6554 bitmap_and_into (vr0->equiv, vr1->equiv);
6555 else if (vr0->equiv && !vr1->equiv)
6556 bitmap_clear (vr0->equiv);
6567 /* Failed to find an efficient meet. Before giving up and setting
6568 the result to VARYING, see if we can at least derive a useful
6569 anti-range. FIXME, all this nonsense about distinguishing
6570 anti-ranges from ranges is necessary because of the odd
6571 semantics of range_includes_zero_p and friends. */
6572 if (!symbolic_range_p (vr0)
6573 && ((vr0->type == VR_RANGE && !range_includes_zero_p (vr0))
6574 || (vr0->type == VR_ANTI_RANGE && range_includes_zero_p (vr0)))
6575 && !symbolic_range_p (vr1)
6576 && ((vr1->type == VR_RANGE && !range_includes_zero_p (vr1))
6577 || (vr1->type == VR_ANTI_RANGE && range_includes_zero_p (vr1))))
6579 set_value_range_to_nonnull (vr0, TREE_TYPE (vr0->min));
6581 /* Since this meet operation did not result from the meeting of
6582 two equivalent names, VR0 cannot have any equivalences. */
6584 bitmap_clear (vr0->equiv);
6587 set_value_range_to_varying (vr0);
6591 /* Visit all arguments for PHI node PHI that flow through executable
6592 edges. If a valid value range can be derived from all the incoming
6593 value ranges, set a new range for the LHS of PHI. */
6595 static enum ssa_prop_result
6596 vrp_visit_phi_node (gimple phi)
6599 tree lhs = PHI_RESULT (phi);
6600 value_range_t *lhs_vr = get_value_range (lhs);
6601 value_range_t vr_result = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
6603 int edges, old_edges;
6606 if (dump_file && (dump_flags & TDF_DETAILS))
6608 fprintf (dump_file, "\nVisiting PHI node: ");
6609 print_gimple_stmt (dump_file, phi, 0, dump_flags);
6613 for (i = 0; i < gimple_phi_num_args (phi); i++)
6615 edge e = gimple_phi_arg_edge (phi, i);
6617 if (dump_file && (dump_flags & TDF_DETAILS))
6620 "\n Argument #%d (%d -> %d %sexecutable)\n",
6621 (int) i, e->src->index, e->dest->index,
6622 (e->flags & EDGE_EXECUTABLE) ? "" : "not ");
6625 if (e->flags & EDGE_EXECUTABLE)
6627 tree arg = PHI_ARG_DEF (phi, i);
6628 value_range_t vr_arg;
6632 if (TREE_CODE (arg) == SSA_NAME)
6634 vr_arg = *(get_value_range (arg));
6638 if (is_overflow_infinity (arg))
6640 arg = copy_node (arg);
6641 TREE_OVERFLOW (arg) = 0;
6644 vr_arg.type = VR_RANGE;
6647 vr_arg.equiv = NULL;
6650 if (dump_file && (dump_flags & TDF_DETAILS))
6652 fprintf (dump_file, "\t");
6653 print_generic_expr (dump_file, arg, dump_flags);
6654 fprintf (dump_file, "\n\tValue: ");
6655 dump_value_range (dump_file, &vr_arg);
6656 fprintf (dump_file, "\n");
6660 copy_value_range (&vr_result, &vr_arg);
6662 vrp_meet (&vr_result, &vr_arg);
6665 if (vr_result.type == VR_VARYING)
6670 if (vr_result.type == VR_VARYING)
6672 else if (vr_result.type == VR_UNDEFINED)
6675 old_edges = vr_phi_edge_counts[SSA_NAME_VERSION (lhs)];
6676 vr_phi_edge_counts[SSA_NAME_VERSION (lhs)] = edges;
6678 /* To prevent infinite iterations in the algorithm, derive ranges
6679 when the new value is slightly bigger or smaller than the
6680 previous one. We don't do this if we have seen a new executable
6681 edge; this helps us avoid an overflow infinity for conditionals
6682 which are not in a loop. */
6684 && gimple_phi_num_args (phi) > 1
6685 && edges == old_edges)
6687 int cmp_min = compare_values (lhs_vr->min, vr_result.min);
6688 int cmp_max = compare_values (lhs_vr->max, vr_result.max);
6690 /* For non VR_RANGE or for pointers fall back to varying if
6691 the range changed. */
6692 if ((lhs_vr->type != VR_RANGE || vr_result.type != VR_RANGE
6693 || POINTER_TYPE_P (TREE_TYPE (lhs)))
6694 && (cmp_min != 0 || cmp_max != 0))
6697 /* If the new minimum is smaller or larger than the previous
6698 one, go all the way to -INF. In the first case, to avoid
6699 iterating millions of times to reach -INF, and in the
6700 other case to avoid infinite bouncing between different
6702 if (cmp_min > 0 || cmp_min < 0)
6704 if (!needs_overflow_infinity (TREE_TYPE (vr_result.min))
6705 || !vrp_var_may_overflow (lhs, phi))
6706 vr_result.min = TYPE_MIN_VALUE (TREE_TYPE (vr_result.min));
6707 else if (supports_overflow_infinity (TREE_TYPE (vr_result.min)))
6709 negative_overflow_infinity (TREE_TYPE (vr_result.min));
6712 /* Similarly, if the new maximum is smaller or larger than
6713 the previous one, go all the way to +INF. */
6714 if (cmp_max < 0 || cmp_max > 0)
6716 if (!needs_overflow_infinity (TREE_TYPE (vr_result.max))
6717 || !vrp_var_may_overflow (lhs, phi))
6718 vr_result.max = TYPE_MAX_VALUE (TREE_TYPE (vr_result.max));
6719 else if (supports_overflow_infinity (TREE_TYPE (vr_result.max)))
6721 positive_overflow_infinity (TREE_TYPE (vr_result.max));
6724 /* If we dropped either bound to +-INF then if this is a loop
6725 PHI node SCEV may known more about its value-range. */
6726 if ((cmp_min > 0 || cmp_min < 0
6727 || cmp_max < 0 || cmp_max > 0)
6729 && (l = loop_containing_stmt (phi))
6730 && l->header == gimple_bb (phi))
6731 adjust_range_with_scev (&vr_result, l, phi, lhs);
6733 /* If we will end up with a (-INF, +INF) range, set it to
6734 VARYING. Same if the previous max value was invalid for
6735 the type and we end up with vr_result.min > vr_result.max. */
6736 if ((vrp_val_is_max (vr_result.max)
6737 && vrp_val_is_min (vr_result.min))
6738 || compare_values (vr_result.min,
6743 /* If the new range is different than the previous value, keep
6746 if (update_value_range (lhs, &vr_result))
6748 if (dump_file && (dump_flags & TDF_DETAILS))
6750 fprintf (dump_file, "Found new range for ");
6751 print_generic_expr (dump_file, lhs, 0);
6752 fprintf (dump_file, ": ");
6753 dump_value_range (dump_file, &vr_result);
6754 fprintf (dump_file, "\n\n");
6757 return SSA_PROP_INTERESTING;
6760 /* Nothing changed, don't add outgoing edges. */
6761 return SSA_PROP_NOT_INTERESTING;
6763 /* No match found. Set the LHS to VARYING. */
6765 set_value_range_to_varying (lhs_vr);
6766 return SSA_PROP_VARYING;
6769 /* Simplify boolean operations if the source is known
6770 to be already a boolean. */
6772 simplify_truth_ops_using_ranges (gimple_stmt_iterator *gsi, gimple stmt)
6774 enum tree_code rhs_code = gimple_assign_rhs_code (stmt);
6776 bool need_conversion;
6778 /* We handle only !=/== case here. */
6779 gcc_assert (rhs_code == EQ_EXPR || rhs_code == NE_EXPR);
6781 op0 = gimple_assign_rhs1 (stmt);
6782 if (!op_with_boolean_value_range_p (op0))
6785 op1 = gimple_assign_rhs2 (stmt);
6786 if (!op_with_boolean_value_range_p (op1))
6789 /* Reduce number of cases to handle to NE_EXPR. As there is no
6790 BIT_XNOR_EXPR we cannot replace A == B with a single statement. */
6791 if (rhs_code == EQ_EXPR)
6793 if (TREE_CODE (op1) == INTEGER_CST)
6794 op1 = int_const_binop (BIT_XOR_EXPR, op1, integer_one_node);
6799 lhs = gimple_assign_lhs (stmt);
6801 = !useless_type_conversion_p (TREE_TYPE (lhs), TREE_TYPE (op0));
6803 /* Make sure to not sign-extend a 1-bit 1 when converting the result. */
6805 && !TYPE_UNSIGNED (TREE_TYPE (op0))
6806 && TYPE_PRECISION (TREE_TYPE (op0)) == 1
6807 && TYPE_PRECISION (TREE_TYPE (lhs)) > 1)
6810 /* For A != 0 we can substitute A itself. */
6811 if (integer_zerop (op1))
6812 gimple_assign_set_rhs_with_ops (gsi,
6814 ? NOP_EXPR : TREE_CODE (op0),
6816 /* For A != B we substitute A ^ B. Either with conversion. */
6817 else if (need_conversion)
6820 tree tem = create_tmp_reg (TREE_TYPE (op0), NULL);
6821 newop = gimple_build_assign_with_ops (BIT_XOR_EXPR, tem, op0, op1);
6822 tem = make_ssa_name (tem, newop);
6823 gimple_assign_set_lhs (newop, tem);
6824 gsi_insert_before (gsi, newop, GSI_SAME_STMT);
6825 update_stmt (newop);
6826 gimple_assign_set_rhs_with_ops (gsi, NOP_EXPR, tem, NULL_TREE);
6830 gimple_assign_set_rhs_with_ops (gsi, BIT_XOR_EXPR, op0, op1);
6831 update_stmt (gsi_stmt (*gsi));
6836 /* Simplify a division or modulo operator to a right shift or
6837 bitwise and if the first operand is unsigned or is greater
6838 than zero and the second operand is an exact power of two. */
6841 simplify_div_or_mod_using_ranges (gimple stmt)
6843 enum tree_code rhs_code = gimple_assign_rhs_code (stmt);
6845 tree op0 = gimple_assign_rhs1 (stmt);
6846 tree op1 = gimple_assign_rhs2 (stmt);
6847 value_range_t *vr = get_value_range (gimple_assign_rhs1 (stmt));
6849 if (TYPE_UNSIGNED (TREE_TYPE (op0)))
6851 val = integer_one_node;
6857 val = compare_range_with_value (GE_EXPR, vr, integer_zero_node, &sop);
6861 && integer_onep (val)
6862 && issue_strict_overflow_warning (WARN_STRICT_OVERFLOW_MISC))
6864 location_t location;
6866 if (!gimple_has_location (stmt))
6867 location = input_location;
6869 location = gimple_location (stmt);
6870 warning_at (location, OPT_Wstrict_overflow,
6871 "assuming signed overflow does not occur when "
6872 "simplifying %</%> or %<%%%> to %<>>%> or %<&%>");
6876 if (val && integer_onep (val))
6880 if (rhs_code == TRUNC_DIV_EXPR)
6882 t = build_int_cst (integer_type_node, tree_log2 (op1));
6883 gimple_assign_set_rhs_code (stmt, RSHIFT_EXPR);
6884 gimple_assign_set_rhs1 (stmt, op0);
6885 gimple_assign_set_rhs2 (stmt, t);
6889 t = build_int_cst (TREE_TYPE (op1), 1);
6890 t = int_const_binop (MINUS_EXPR, op1, t);
6891 t = fold_convert (TREE_TYPE (op0), t);
6893 gimple_assign_set_rhs_code (stmt, BIT_AND_EXPR);
6894 gimple_assign_set_rhs1 (stmt, op0);
6895 gimple_assign_set_rhs2 (stmt, t);
6905 /* If the operand to an ABS_EXPR is >= 0, then eliminate the
6906 ABS_EXPR. If the operand is <= 0, then simplify the
6907 ABS_EXPR into a NEGATE_EXPR. */
6910 simplify_abs_using_ranges (gimple stmt)
6913 tree op = gimple_assign_rhs1 (stmt);
6914 tree type = TREE_TYPE (op);
6915 value_range_t *vr = get_value_range (op);
6917 if (TYPE_UNSIGNED (type))
6919 val = integer_zero_node;
6925 val = compare_range_with_value (LE_EXPR, vr, integer_zero_node, &sop);
6929 val = compare_range_with_value (GE_EXPR, vr, integer_zero_node,
6934 if (integer_zerop (val))
6935 val = integer_one_node;
6936 else if (integer_onep (val))
6937 val = integer_zero_node;
6942 && (integer_onep (val) || integer_zerop (val)))
6944 if (sop && issue_strict_overflow_warning (WARN_STRICT_OVERFLOW_MISC))
6946 location_t location;
6948 if (!gimple_has_location (stmt))
6949 location = input_location;
6951 location = gimple_location (stmt);
6952 warning_at (location, OPT_Wstrict_overflow,
6953 "assuming signed overflow does not occur when "
6954 "simplifying %<abs (X)%> to %<X%> or %<-X%>");
6957 gimple_assign_set_rhs1 (stmt, op);
6958 if (integer_onep (val))
6959 gimple_assign_set_rhs_code (stmt, NEGATE_EXPR);
6961 gimple_assign_set_rhs_code (stmt, SSA_NAME);
6970 /* Optimize away redundant BIT_AND_EXPR and BIT_IOR_EXPR.
6971 If all the bits that are being cleared by & are already
6972 known to be zero from VR, or all the bits that are being
6973 set by | are already known to be one from VR, the bit
6974 operation is redundant. */
6977 simplify_bit_ops_using_ranges (gimple_stmt_iterator *gsi, gimple stmt)
6979 tree op0 = gimple_assign_rhs1 (stmt);
6980 tree op1 = gimple_assign_rhs2 (stmt);
6981 tree op = NULL_TREE;
6982 value_range_t vr0 = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
6983 value_range_t vr1 = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
6984 double_int may_be_nonzero0, may_be_nonzero1;
6985 double_int must_be_nonzero0, must_be_nonzero1;
6988 if (TREE_CODE (op0) == SSA_NAME)
6989 vr0 = *(get_value_range (op0));
6990 else if (is_gimple_min_invariant (op0))
6991 set_value_range_to_value (&vr0, op0, NULL);
6995 if (TREE_CODE (op1) == SSA_NAME)
6996 vr1 = *(get_value_range (op1));
6997 else if (is_gimple_min_invariant (op1))
6998 set_value_range_to_value (&vr1, op1, NULL);
7002 if (!zero_nonzero_bits_from_vr (&vr0, &may_be_nonzero0, &must_be_nonzero0))
7004 if (!zero_nonzero_bits_from_vr (&vr1, &may_be_nonzero1, &must_be_nonzero1))
7007 switch (gimple_assign_rhs_code (stmt))
7010 mask = double_int_and_not (may_be_nonzero0, must_be_nonzero1);
7011 if (double_int_zero_p (mask))
7016 mask = double_int_and_not (may_be_nonzero1, must_be_nonzero0);
7017 if (double_int_zero_p (mask))
7024 mask = double_int_and_not (may_be_nonzero0, must_be_nonzero1);
7025 if (double_int_zero_p (mask))
7030 mask = double_int_and_not (may_be_nonzero1, must_be_nonzero0);
7031 if (double_int_zero_p (mask))
7041 if (op == NULL_TREE)
7044 gimple_assign_set_rhs_with_ops (gsi, TREE_CODE (op), op, NULL);
7045 update_stmt (gsi_stmt (*gsi));
7049 /* We are comparing trees OP0 and OP1 using COND_CODE. OP0 has
7050 a known value range VR.
7052 If there is one and only one value which will satisfy the
7053 conditional, then return that value. Else return NULL. */
7056 test_for_singularity (enum tree_code cond_code, tree op0,
7057 tree op1, value_range_t *vr)
7062 /* Extract minimum/maximum values which satisfy the
7063 the conditional as it was written. */
7064 if (cond_code == LE_EXPR || cond_code == LT_EXPR)
7066 /* This should not be negative infinity; there is no overflow
7068 min = TYPE_MIN_VALUE (TREE_TYPE (op0));
7071 if (cond_code == LT_EXPR && !is_overflow_infinity (max))
7073 tree one = build_int_cst (TREE_TYPE (op0), 1);
7074 max = fold_build2 (MINUS_EXPR, TREE_TYPE (op0), max, one);
7076 TREE_NO_WARNING (max) = 1;
7079 else if (cond_code == GE_EXPR || cond_code == GT_EXPR)
7081 /* This should not be positive infinity; there is no overflow
7083 max = TYPE_MAX_VALUE (TREE_TYPE (op0));
7086 if (cond_code == GT_EXPR && !is_overflow_infinity (min))
7088 tree one = build_int_cst (TREE_TYPE (op0), 1);
7089 min = fold_build2 (PLUS_EXPR, TREE_TYPE (op0), min, one);
7091 TREE_NO_WARNING (min) = 1;
7095 /* Now refine the minimum and maximum values using any
7096 value range information we have for op0. */
7099 if (compare_values (vr->min, min) == 1)
7101 if (compare_values (vr->max, max) == -1)
7104 /* If the new min/max values have converged to a single value,
7105 then there is only one value which can satisfy the condition,
7106 return that value. */
7107 if (operand_equal_p (min, max, 0) && is_gimple_min_invariant (min))
7113 /* Simplify a conditional using a relational operator to an equality
7114 test if the range information indicates only one value can satisfy
7115 the original conditional. */
7118 simplify_cond_using_ranges (gimple stmt)
7120 tree op0 = gimple_cond_lhs (stmt);
7121 tree op1 = gimple_cond_rhs (stmt);
7122 enum tree_code cond_code = gimple_cond_code (stmt);
7124 if (cond_code != NE_EXPR
7125 && cond_code != EQ_EXPR
7126 && TREE_CODE (op0) == SSA_NAME
7127 && INTEGRAL_TYPE_P (TREE_TYPE (op0))
7128 && is_gimple_min_invariant (op1))
7130 value_range_t *vr = get_value_range (op0);
7132 /* If we have range information for OP0, then we might be
7133 able to simplify this conditional. */
7134 if (vr->type == VR_RANGE)
7136 tree new_tree = test_for_singularity (cond_code, op0, op1, vr);
7142 fprintf (dump_file, "Simplified relational ");
7143 print_gimple_stmt (dump_file, stmt, 0, 0);
7144 fprintf (dump_file, " into ");
7147 gimple_cond_set_code (stmt, EQ_EXPR);
7148 gimple_cond_set_lhs (stmt, op0);
7149 gimple_cond_set_rhs (stmt, new_tree);
7155 print_gimple_stmt (dump_file, stmt, 0, 0);
7156 fprintf (dump_file, "\n");
7162 /* Try again after inverting the condition. We only deal
7163 with integral types here, so no need to worry about
7164 issues with inverting FP comparisons. */
7165 cond_code = invert_tree_comparison (cond_code, false);
7166 new_tree = test_for_singularity (cond_code, op0, op1, vr);
7172 fprintf (dump_file, "Simplified relational ");
7173 print_gimple_stmt (dump_file, stmt, 0, 0);
7174 fprintf (dump_file, " into ");
7177 gimple_cond_set_code (stmt, NE_EXPR);
7178 gimple_cond_set_lhs (stmt, op0);
7179 gimple_cond_set_rhs (stmt, new_tree);
7185 print_gimple_stmt (dump_file, stmt, 0, 0);
7186 fprintf (dump_file, "\n");
7197 /* Simplify a switch statement using the value range of the switch
7201 simplify_switch_using_ranges (gimple stmt)
7203 tree op = gimple_switch_index (stmt);
7208 size_t i = 0, j = 0, n, n2;
7212 if (TREE_CODE (op) == SSA_NAME)
7214 vr = get_value_range (op);
7216 /* We can only handle integer ranges. */
7217 if (vr->type != VR_RANGE
7218 || symbolic_range_p (vr))
7221 /* Find case label for min/max of the value range. */
7222 take_default = !find_case_label_range (stmt, vr->min, vr->max, &i, &j);
7224 else if (TREE_CODE (op) == INTEGER_CST)
7226 take_default = !find_case_label_index (stmt, 1, op, &i);
7240 n = gimple_switch_num_labels (stmt);
7242 /* Bail out if this is just all edges taken. */
7248 /* Build a new vector of taken case labels. */
7249 vec2 = make_tree_vec (j - i + 1 + (int)take_default);
7252 /* Add the default edge, if necessary. */
7254 TREE_VEC_ELT (vec2, n2++) = gimple_switch_default_label (stmt);
7256 for (; i <= j; ++i, ++n2)
7257 TREE_VEC_ELT (vec2, n2) = gimple_switch_label (stmt, i);
7259 /* Mark needed edges. */
7260 for (i = 0; i < n2; ++i)
7262 e = find_edge (gimple_bb (stmt),
7263 label_to_block (CASE_LABEL (TREE_VEC_ELT (vec2, i))));
7264 e->aux = (void *)-1;
7267 /* Queue not needed edges for later removal. */
7268 FOR_EACH_EDGE (e, ei, gimple_bb (stmt)->succs)
7270 if (e->aux == (void *)-1)
7276 if (dump_file && (dump_flags & TDF_DETAILS))
7278 fprintf (dump_file, "removing unreachable case label\n");
7280 VEC_safe_push (edge, heap, to_remove_edges, e);
7281 e->flags &= ~EDGE_EXECUTABLE;
7284 /* And queue an update for the stmt. */
7287 VEC_safe_push (switch_update, heap, to_update_switch_stmts, &su);
7291 /* Simplify an integral conversion from an SSA name in STMT. */
7294 simplify_conversion_using_ranges (gimple stmt)
7296 tree innerop, middleop, finaltype;
7298 value_range_t *innervr;
7299 bool inner_unsigned_p, middle_unsigned_p, final_unsigned_p;
7300 unsigned inner_prec, middle_prec, final_prec;
7301 double_int innermin, innermed, innermax, middlemin, middlemed, middlemax;
7303 finaltype = TREE_TYPE (gimple_assign_lhs (stmt));
7304 if (!INTEGRAL_TYPE_P (finaltype))
7306 middleop = gimple_assign_rhs1 (stmt);
7307 def_stmt = SSA_NAME_DEF_STMT (middleop);
7308 if (!is_gimple_assign (def_stmt)
7309 || !CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (def_stmt)))
7311 innerop = gimple_assign_rhs1 (def_stmt);
7312 if (TREE_CODE (innerop) != SSA_NAME)
7315 /* Get the value-range of the inner operand. */
7316 innervr = get_value_range (innerop);
7317 if (innervr->type != VR_RANGE
7318 || TREE_CODE (innervr->min) != INTEGER_CST
7319 || TREE_CODE (innervr->max) != INTEGER_CST)
7322 /* Simulate the conversion chain to check if the result is equal if
7323 the middle conversion is removed. */
7324 innermin = tree_to_double_int (innervr->min);
7325 innermax = tree_to_double_int (innervr->max);
7327 inner_prec = TYPE_PRECISION (TREE_TYPE (innerop));
7328 middle_prec = TYPE_PRECISION (TREE_TYPE (middleop));
7329 final_prec = TYPE_PRECISION (finaltype);
7331 /* If the first conversion is not injective, the second must not
7333 if (double_int_cmp (double_int_sub (innermax, innermin),
7334 double_int_mask (middle_prec), true) > 0
7335 && middle_prec < final_prec)
7337 /* We also want a medium value so that we can track the effect that
7338 narrowing conversions with sign change have. */
7339 inner_unsigned_p = TYPE_UNSIGNED (TREE_TYPE (innerop));
7340 if (inner_unsigned_p)
7341 innermed = double_int_rshift (double_int_mask (inner_prec),
7342 1, inner_prec, false);
7344 innermed = double_int_zero;
7345 if (double_int_cmp (innermin, innermed, inner_unsigned_p) >= 0
7346 || double_int_cmp (innermed, innermax, inner_unsigned_p) >= 0)
7347 innermed = innermin;
7349 middle_unsigned_p = TYPE_UNSIGNED (TREE_TYPE (middleop));
7350 middlemin = double_int_ext (innermin, middle_prec, middle_unsigned_p);
7351 middlemed = double_int_ext (innermed, middle_prec, middle_unsigned_p);
7352 middlemax = double_int_ext (innermax, middle_prec, middle_unsigned_p);
7354 /* Require that the final conversion applied to both the original
7355 and the intermediate range produces the same result. */
7356 final_unsigned_p = TYPE_UNSIGNED (finaltype);
7357 if (!double_int_equal_p (double_int_ext (middlemin,
7358 final_prec, final_unsigned_p),
7359 double_int_ext (innermin,
7360 final_prec, final_unsigned_p))
7361 || !double_int_equal_p (double_int_ext (middlemed,
7362 final_prec, final_unsigned_p),
7363 double_int_ext (innermed,
7364 final_prec, final_unsigned_p))
7365 || !double_int_equal_p (double_int_ext (middlemax,
7366 final_prec, final_unsigned_p),
7367 double_int_ext (innermax,
7368 final_prec, final_unsigned_p)))
7371 gimple_assign_set_rhs1 (stmt, innerop);
7376 /* Return whether the value range *VR fits in an integer type specified
7377 by PRECISION and UNSIGNED_P. */
7380 range_fits_type_p (value_range_t *vr, unsigned precision, bool unsigned_p)
7383 unsigned src_precision;
7386 /* We can only handle integral and pointer types. */
7387 src_type = TREE_TYPE (vr->min);
7388 if (!INTEGRAL_TYPE_P (src_type)
7389 && !POINTER_TYPE_P (src_type))
7392 /* An extension is always fine, so is an identity transform. */
7393 src_precision = TYPE_PRECISION (TREE_TYPE (vr->min));
7394 if (src_precision < precision
7395 || (src_precision == precision
7396 && TYPE_UNSIGNED (src_type) == unsigned_p))
7399 /* Now we can only handle ranges with constant bounds. */
7400 if (vr->type != VR_RANGE
7401 || TREE_CODE (vr->min) != INTEGER_CST
7402 || TREE_CODE (vr->max) != INTEGER_CST)
7405 /* For precision-preserving sign-changes the MSB of the double-int
7407 if (src_precision == precision
7408 && (TREE_INT_CST_HIGH (vr->min) | TREE_INT_CST_HIGH (vr->max)) < 0)
7411 /* Then we can perform the conversion on both ends and compare
7412 the result for equality. */
7413 tem = double_int_ext (tree_to_double_int (vr->min), precision, unsigned_p);
7414 if (!double_int_equal_p (tree_to_double_int (vr->min), tem))
7416 tem = double_int_ext (tree_to_double_int (vr->max), precision, unsigned_p);
7417 if (!double_int_equal_p (tree_to_double_int (vr->max), tem))
7423 /* Simplify a conversion from integral SSA name to float in STMT. */
7426 simplify_float_conversion_using_ranges (gimple_stmt_iterator *gsi, gimple stmt)
7428 tree rhs1 = gimple_assign_rhs1 (stmt);
7429 value_range_t *vr = get_value_range (rhs1);
7430 enum machine_mode fltmode = TYPE_MODE (TREE_TYPE (gimple_assign_lhs (stmt)));
7431 enum machine_mode mode;
7435 /* We can only handle constant ranges. */
7436 if (vr->type != VR_RANGE
7437 || TREE_CODE (vr->min) != INTEGER_CST
7438 || TREE_CODE (vr->max) != INTEGER_CST)
7441 /* First check if we can use a signed type in place of an unsigned. */
7442 if (TYPE_UNSIGNED (TREE_TYPE (rhs1))
7443 && (can_float_p (fltmode, TYPE_MODE (TREE_TYPE (rhs1)), 0)
7444 != CODE_FOR_nothing)
7445 && range_fits_type_p (vr, GET_MODE_PRECISION
7446 (TYPE_MODE (TREE_TYPE (rhs1))), 0))
7447 mode = TYPE_MODE (TREE_TYPE (rhs1));
7448 /* If we can do the conversion in the current input mode do nothing. */
7449 else if (can_float_p (fltmode, TYPE_MODE (TREE_TYPE (rhs1)),
7450 TYPE_UNSIGNED (TREE_TYPE (rhs1))))
7452 /* Otherwise search for a mode we can use, starting from the narrowest
7453 integer mode available. */
7456 mode = GET_CLASS_NARROWEST_MODE (MODE_INT);
7459 /* If we cannot do a signed conversion to float from mode
7460 or if the value-range does not fit in the signed type
7461 try with a wider mode. */
7462 if (can_float_p (fltmode, mode, 0) != CODE_FOR_nothing
7463 && range_fits_type_p (vr, GET_MODE_PRECISION (mode), 0))
7466 mode = GET_MODE_WIDER_MODE (mode);
7467 /* But do not widen the input. Instead leave that to the
7468 optabs expansion code. */
7469 if (GET_MODE_PRECISION (mode) > TYPE_PRECISION (TREE_TYPE (rhs1)))
7472 while (mode != VOIDmode);
7473 if (mode == VOIDmode)
7477 /* It works, insert a truncation or sign-change before the
7478 float conversion. */
7479 tem = create_tmp_var (build_nonstandard_integer_type
7480 (GET_MODE_PRECISION (mode), 0), NULL);
7481 conv = gimple_build_assign_with_ops (NOP_EXPR, tem, rhs1, NULL_TREE);
7482 tem = make_ssa_name (tem, conv);
7483 gimple_assign_set_lhs (conv, tem);
7484 gsi_insert_before (gsi, conv, GSI_SAME_STMT);
7485 gimple_assign_set_rhs1 (stmt, tem);
7491 /* Simplify STMT using ranges if possible. */
7494 simplify_stmt_using_ranges (gimple_stmt_iterator *gsi)
7496 gimple stmt = gsi_stmt (*gsi);
7497 if (is_gimple_assign (stmt))
7499 enum tree_code rhs_code = gimple_assign_rhs_code (stmt);
7500 tree rhs1 = gimple_assign_rhs1 (stmt);
7506 /* Transform EQ_EXPR, NE_EXPR into BIT_XOR_EXPR or identity
7507 if the RHS is zero or one, and the LHS are known to be boolean
7509 if (INTEGRAL_TYPE_P (TREE_TYPE (rhs1)))
7510 return simplify_truth_ops_using_ranges (gsi, stmt);
7513 /* Transform TRUNC_DIV_EXPR and TRUNC_MOD_EXPR into RSHIFT_EXPR
7514 and BIT_AND_EXPR respectively if the first operand is greater
7515 than zero and the second operand is an exact power of two. */
7516 case TRUNC_DIV_EXPR:
7517 case TRUNC_MOD_EXPR:
7518 if (INTEGRAL_TYPE_P (TREE_TYPE (rhs1))
7519 && integer_pow2p (gimple_assign_rhs2 (stmt)))
7520 return simplify_div_or_mod_using_ranges (stmt);
7523 /* Transform ABS (X) into X or -X as appropriate. */
7525 if (TREE_CODE (rhs1) == SSA_NAME
7526 && INTEGRAL_TYPE_P (TREE_TYPE (rhs1)))
7527 return simplify_abs_using_ranges (stmt);
7532 /* Optimize away BIT_AND_EXPR and BIT_IOR_EXPR
7533 if all the bits being cleared are already cleared or
7534 all the bits being set are already set. */
7535 if (INTEGRAL_TYPE_P (TREE_TYPE (rhs1)))
7536 return simplify_bit_ops_using_ranges (gsi, stmt);
7540 if (TREE_CODE (rhs1) == SSA_NAME
7541 && INTEGRAL_TYPE_P (TREE_TYPE (rhs1)))
7542 return simplify_conversion_using_ranges (stmt);
7546 if (TREE_CODE (rhs1) == SSA_NAME
7547 && INTEGRAL_TYPE_P (TREE_TYPE (rhs1)))
7548 return simplify_float_conversion_using_ranges (gsi, stmt);
7555 else if (gimple_code (stmt) == GIMPLE_COND)
7556 return simplify_cond_using_ranges (stmt);
7557 else if (gimple_code (stmt) == GIMPLE_SWITCH)
7558 return simplify_switch_using_ranges (stmt);
7563 /* If the statement pointed by SI has a predicate whose value can be
7564 computed using the value range information computed by VRP, compute
7565 its value and return true. Otherwise, return false. */
7568 fold_predicate_in (gimple_stmt_iterator *si)
7570 bool assignment_p = false;
7572 gimple stmt = gsi_stmt (*si);
7574 if (is_gimple_assign (stmt)
7575 && TREE_CODE_CLASS (gimple_assign_rhs_code (stmt)) == tcc_comparison)
7577 assignment_p = true;
7578 val = vrp_evaluate_conditional (gimple_assign_rhs_code (stmt),
7579 gimple_assign_rhs1 (stmt),
7580 gimple_assign_rhs2 (stmt),
7583 else if (gimple_code (stmt) == GIMPLE_COND)
7584 val = vrp_evaluate_conditional (gimple_cond_code (stmt),
7585 gimple_cond_lhs (stmt),
7586 gimple_cond_rhs (stmt),
7594 val = fold_convert (gimple_expr_type (stmt), val);
7598 fprintf (dump_file, "Folding predicate ");
7599 print_gimple_expr (dump_file, stmt, 0, 0);
7600 fprintf (dump_file, " to ");
7601 print_generic_expr (dump_file, val, 0);
7602 fprintf (dump_file, "\n");
7605 if (is_gimple_assign (stmt))
7606 gimple_assign_set_rhs_from_tree (si, val);
7609 gcc_assert (gimple_code (stmt) == GIMPLE_COND);
7610 if (integer_zerop (val))
7611 gimple_cond_make_false (stmt);
7612 else if (integer_onep (val))
7613 gimple_cond_make_true (stmt);
7624 /* Callback for substitute_and_fold folding the stmt at *SI. */
7627 vrp_fold_stmt (gimple_stmt_iterator *si)
7629 if (fold_predicate_in (si))
7632 return simplify_stmt_using_ranges (si);
7635 /* Stack of dest,src equivalency pairs that need to be restored after
7636 each attempt to thread a block's incoming edge to an outgoing edge.
7638 A NULL entry is used to mark the end of pairs which need to be
7640 static VEC(tree,heap) *stack;
7642 /* A trivial wrapper so that we can present the generic jump threading
7643 code with a simple API for simplifying statements. STMT is the
7644 statement we want to simplify, WITHIN_STMT provides the location
7645 for any overflow warnings. */
7648 simplify_stmt_for_jump_threading (gimple stmt, gimple within_stmt)
7650 /* We only use VRP information to simplify conditionals. This is
7651 overly conservative, but it's unclear if doing more would be
7652 worth the compile time cost. */
7653 if (gimple_code (stmt) != GIMPLE_COND)
7656 return vrp_evaluate_conditional (gimple_cond_code (stmt),
7657 gimple_cond_lhs (stmt),
7658 gimple_cond_rhs (stmt), within_stmt);
7661 /* Blocks which have more than one predecessor and more than
7662 one successor present jump threading opportunities, i.e.,
7663 when the block is reached from a specific predecessor, we
7664 may be able to determine which of the outgoing edges will
7665 be traversed. When this optimization applies, we are able
7666 to avoid conditionals at runtime and we may expose secondary
7667 optimization opportunities.
7669 This routine is effectively a driver for the generic jump
7670 threading code. It basically just presents the generic code
7671 with edges that may be suitable for jump threading.
7673 Unlike DOM, we do not iterate VRP if jump threading was successful.
7674 While iterating may expose new opportunities for VRP, it is expected
7675 those opportunities would be very limited and the compile time cost
7676 to expose those opportunities would be significant.
7678 As jump threading opportunities are discovered, they are registered
7679 for later realization. */
7682 identify_jump_threads (void)
7689 /* Ugh. When substituting values earlier in this pass we can
7690 wipe the dominance information. So rebuild the dominator
7691 information as we need it within the jump threading code. */
7692 calculate_dominance_info (CDI_DOMINATORS);
7694 /* We do not allow VRP information to be used for jump threading
7695 across a back edge in the CFG. Otherwise it becomes too
7696 difficult to avoid eliminating loop exit tests. Of course
7697 EDGE_DFS_BACK is not accurate at this time so we have to
7699 mark_dfs_back_edges ();
7701 /* Do not thread across edges we are about to remove. Just marking
7702 them as EDGE_DFS_BACK will do. */
7703 FOR_EACH_VEC_ELT (edge, to_remove_edges, i, e)
7704 e->flags |= EDGE_DFS_BACK;
7706 /* Allocate our unwinder stack to unwind any temporary equivalences
7707 that might be recorded. */
7708 stack = VEC_alloc (tree, heap, 20);
7710 /* To avoid lots of silly node creation, we create a single
7711 conditional and just modify it in-place when attempting to
7713 dummy = gimple_build_cond (EQ_EXPR,
7714 integer_zero_node, integer_zero_node,
7717 /* Walk through all the blocks finding those which present a
7718 potential jump threading opportunity. We could set this up
7719 as a dominator walker and record data during the walk, but
7720 I doubt it's worth the effort for the classes of jump
7721 threading opportunities we are trying to identify at this
7722 point in compilation. */
7727 /* If the generic jump threading code does not find this block
7728 interesting, then there is nothing to do. */
7729 if (! potentially_threadable_block (bb))
7732 /* We only care about blocks ending in a COND_EXPR. While there
7733 may be some value in handling SWITCH_EXPR here, I doubt it's
7734 terribly important. */
7735 last = gsi_stmt (gsi_last_bb (bb));
7737 /* We're basically looking for a switch or any kind of conditional with
7738 integral or pointer type arguments. Note the type of the second
7739 argument will be the same as the first argument, so no need to
7740 check it explicitly. */
7741 if (gimple_code (last) == GIMPLE_SWITCH
7742 || (gimple_code (last) == GIMPLE_COND
7743 && TREE_CODE (gimple_cond_lhs (last)) == SSA_NAME
7744 && (INTEGRAL_TYPE_P (TREE_TYPE (gimple_cond_lhs (last)))
7745 || POINTER_TYPE_P (TREE_TYPE (gimple_cond_lhs (last))))
7746 && (TREE_CODE (gimple_cond_rhs (last)) == SSA_NAME
7747 || is_gimple_min_invariant (gimple_cond_rhs (last)))))
7751 /* We've got a block with multiple predecessors and multiple
7752 successors which also ends in a suitable conditional or
7753 switch statement. For each predecessor, see if we can thread
7754 it to a specific successor. */
7755 FOR_EACH_EDGE (e, ei, bb->preds)
7757 /* Do not thread across back edges or abnormal edges
7759 if (e->flags & (EDGE_DFS_BACK | EDGE_COMPLEX))
7762 thread_across_edge (dummy, e, true, &stack,
7763 simplify_stmt_for_jump_threading);
7768 /* We do not actually update the CFG or SSA graphs at this point as
7769 ASSERT_EXPRs are still in the IL and cfg cleanup code does not yet
7770 handle ASSERT_EXPRs gracefully. */
7773 /* We identified all the jump threading opportunities earlier, but could
7774 not transform the CFG at that time. This routine transforms the
7775 CFG and arranges for the dominator tree to be rebuilt if necessary.
7777 Note the SSA graph update will occur during the normal TODO
7778 processing by the pass manager. */
7780 finalize_jump_threads (void)
7782 thread_through_all_blocks (false);
7783 VEC_free (tree, heap, stack);
7787 /* Traverse all the blocks folding conditionals with known ranges. */
7794 values_propagated = true;
7798 fprintf (dump_file, "\nValue ranges after VRP:\n\n");
7799 dump_all_value_ranges (dump_file);
7800 fprintf (dump_file, "\n");
7803 substitute_and_fold (op_with_constant_singleton_value_range,
7804 vrp_fold_stmt, false);
7806 if (warn_array_bounds)
7807 check_all_array_refs ();
7809 /* We must identify jump threading opportunities before we release
7810 the datastructures built by VRP. */
7811 identify_jump_threads ();
7813 /* Free allocated memory. */
7814 for (i = 0; i < num_vr_values; i++)
7817 BITMAP_FREE (vr_value[i]->equiv);
7822 free (vr_phi_edge_counts);
7824 /* So that we can distinguish between VRP data being available
7825 and not available. */
7827 vr_phi_edge_counts = NULL;
7831 /* Main entry point to VRP (Value Range Propagation). This pass is
7832 loosely based on J. R. C. Patterson, ``Accurate Static Branch
7833 Prediction by Value Range Propagation,'' in SIGPLAN Conference on
7834 Programming Language Design and Implementation, pp. 67-78, 1995.
7835 Also available at http://citeseer.ist.psu.edu/patterson95accurate.html
7837 This is essentially an SSA-CCP pass modified to deal with ranges
7838 instead of constants.
7840 While propagating ranges, we may find that two or more SSA name
7841 have equivalent, though distinct ranges. For instance,
7844 2 p_4 = ASSERT_EXPR <p_3, p_3 != 0>
7846 4 p_5 = ASSERT_EXPR <p_4, p_4 == q_2>;
7850 In the code above, pointer p_5 has range [q_2, q_2], but from the
7851 code we can also determine that p_5 cannot be NULL and, if q_2 had
7852 a non-varying range, p_5's range should also be compatible with it.
7854 These equivalences are created by two expressions: ASSERT_EXPR and
7855 copy operations. Since p_5 is an assertion on p_4, and p_4 was the
7856 result of another assertion, then we can use the fact that p_5 and
7857 p_4 are equivalent when evaluating p_5's range.
7859 Together with value ranges, we also propagate these equivalences
7860 between names so that we can take advantage of information from
7861 multiple ranges when doing final replacement. Note that this
7862 equivalency relation is transitive but not symmetric.
7864 In the example above, p_5 is equivalent to p_4, q_2 and p_3, but we
7865 cannot assert that q_2 is equivalent to p_5 because q_2 may be used
7866 in contexts where that assertion does not hold (e.g., in line 6).
7868 TODO, the main difference between this pass and Patterson's is that
7869 we do not propagate edge probabilities. We only compute whether
7870 edges can be taken or not. That is, instead of having a spectrum
7871 of jump probabilities between 0 and 1, we only deal with 0, 1 and
7872 DON'T KNOW. In the future, it may be worthwhile to propagate
7873 probabilities to aid branch prediction. */
7882 loop_optimizer_init (LOOPS_NORMAL | LOOPS_HAVE_RECORDED_EXITS);
7883 rewrite_into_loop_closed_ssa (NULL, TODO_update_ssa);
7886 insert_range_assertions ();
7888 /* Estimate number of iterations - but do not use undefined behavior
7889 for this. We can't do this lazily as other functions may compute
7890 this using undefined behavior. */
7891 free_numbers_of_iterations_estimates ();
7892 estimate_numbers_of_iterations (false);
7894 to_remove_edges = VEC_alloc (edge, heap, 10);
7895 to_update_switch_stmts = VEC_alloc (switch_update, heap, 5);
7896 threadedge_initialize_values ();
7899 ssa_propagate (vrp_visit_stmt, vrp_visit_phi_node);
7902 free_numbers_of_iterations_estimates ();
7904 /* ASSERT_EXPRs must be removed before finalizing jump threads
7905 as finalizing jump threads calls the CFG cleanup code which
7906 does not properly handle ASSERT_EXPRs. */
7907 remove_range_assertions ();
7909 /* If we exposed any new variables, go ahead and put them into
7910 SSA form now, before we handle jump threading. This simplifies
7911 interactions between rewriting of _DECL nodes into SSA form
7912 and rewriting SSA_NAME nodes into SSA form after block
7913 duplication and CFG manipulation. */
7914 update_ssa (TODO_update_ssa);
7916 finalize_jump_threads ();
7918 /* Remove dead edges from SWITCH_EXPR optimization. This leaves the
7919 CFG in a broken state and requires a cfg_cleanup run. */
7920 FOR_EACH_VEC_ELT (edge, to_remove_edges, i, e)
7922 /* Update SWITCH_EXPR case label vector. */
7923 FOR_EACH_VEC_ELT (switch_update, to_update_switch_stmts, i, su)
7926 size_t n = TREE_VEC_LENGTH (su->vec);
7928 gimple_switch_set_num_labels (su->stmt, n);
7929 for (j = 0; j < n; j++)
7930 gimple_switch_set_label (su->stmt, j, TREE_VEC_ELT (su->vec, j));
7931 /* As we may have replaced the default label with a regular one
7932 make sure to make it a real default label again. This ensures
7933 optimal expansion. */
7934 label = gimple_switch_default_label (su->stmt);
7935 CASE_LOW (label) = NULL_TREE;
7936 CASE_HIGH (label) = NULL_TREE;
7939 if (VEC_length (edge, to_remove_edges) > 0)
7940 free_dominance_info (CDI_DOMINATORS);
7942 VEC_free (edge, heap, to_remove_edges);
7943 VEC_free (switch_update, heap, to_update_switch_stmts);
7944 threadedge_finalize_values ();
7947 loop_optimizer_finalize ();
7954 return flag_tree_vrp != 0;
7957 struct gimple_opt_pass pass_vrp =
7962 gate_vrp, /* gate */
7963 execute_vrp, /* execute */
7966 0, /* static_pass_number */
7967 TV_TREE_VRP, /* tv_id */
7968 PROP_ssa, /* properties_required */
7969 0, /* properties_provided */
7970 0, /* properties_destroyed */
7971 0, /* todo_flags_start */
7976 | TODO_ggc_collect /* todo_flags_finish */