1 /* Support routines for Value Range Propagation (VRP).
2 Copyright (C) 2005, 2006, 2007, 2008, 2009, 2010, 2011
3 Free Software Foundation, Inc.
4 Contributed by Diego Novillo <dnovillo@redhat.com>.
6 This file is part of GCC.
8 GCC is free software; you can redistribute it and/or modify
9 it under the terms of the GNU General Public License as published by
10 the Free Software Foundation; either version 3, or (at your option)
13 GCC is distributed in the hope that it will be useful,
14 but WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 GNU General Public License for more details.
18 You should have received a copy of the GNU General Public License
19 along with GCC; see the file COPYING3. If not see
20 <http://www.gnu.org/licenses/>. */
24 #include "coretypes.h"
29 #include "basic-block.h"
30 #include "tree-flow.h"
31 #include "tree-pass.h"
32 #include "tree-dump.h"
34 #include "tree-pretty-print.h"
35 #include "gimple-pretty-print.h"
36 #include "diagnostic-core.h"
39 #include "tree-scalar-evolution.h"
40 #include "tree-ssa-propagate.h"
41 #include "tree-chrec.h"
42 #include "gimple-fold.h"
47 /* Type of value ranges. See value_range_d for a description of these
49 enum value_range_type { VR_UNDEFINED, VR_RANGE, VR_ANTI_RANGE, VR_VARYING };
51 /* Range of values that can be associated with an SSA_NAME after VRP
55 /* Lattice value represented by this range. */
56 enum value_range_type type;
58 /* Minimum and maximum values represented by this range. These
59 values should be interpreted as follows:
61 - If TYPE is VR_UNDEFINED or VR_VARYING then MIN and MAX must
64 - If TYPE == VR_RANGE then MIN holds the minimum value and
65 MAX holds the maximum value of the range [MIN, MAX].
67 - If TYPE == ANTI_RANGE the variable is known to NOT
68 take any values in the range [MIN, MAX]. */
72 /* Set of SSA names whose value ranges are equivalent to this one.
73 This set is only valid when TYPE is VR_RANGE or VR_ANTI_RANGE. */
77 typedef struct value_range_d value_range_t;
79 /* Set of SSA names found live during the RPO traversal of the function
80 for still active basic-blocks. */
83 /* Return true if the SSA name NAME is live on the edge E. */
86 live_on_edge (edge e, tree name)
88 return (live[e->dest->index]
89 && TEST_BIT (live[e->dest->index], SSA_NAME_VERSION (name)));
92 /* Local functions. */
93 static int compare_values (tree val1, tree val2);
94 static int compare_values_warnv (tree val1, tree val2, bool *);
95 static void vrp_meet (value_range_t *, value_range_t *);
96 static tree vrp_evaluate_conditional_warnv_with_ops (enum tree_code,
97 tree, tree, bool, bool *,
100 /* Location information for ASSERT_EXPRs. Each instance of this
101 structure describes an ASSERT_EXPR for an SSA name. Since a single
102 SSA name may have more than one assertion associated with it, these
103 locations are kept in a linked list attached to the corresponding
105 struct assert_locus_d
107 /* Basic block where the assertion would be inserted. */
110 /* Some assertions need to be inserted on an edge (e.g., assertions
111 generated by COND_EXPRs). In those cases, BB will be NULL. */
114 /* Pointer to the statement that generated this assertion. */
115 gimple_stmt_iterator si;
117 /* Predicate code for the ASSERT_EXPR. Must be COMPARISON_CLASS_P. */
118 enum tree_code comp_code;
120 /* Value being compared against. */
123 /* Expression to compare. */
126 /* Next node in the linked list. */
127 struct assert_locus_d *next;
130 typedef struct assert_locus_d *assert_locus_t;
132 /* If bit I is present, it means that SSA name N_i has a list of
133 assertions that should be inserted in the IL. */
134 static bitmap need_assert_for;
136 /* Array of locations lists where to insert assertions. ASSERTS_FOR[I]
137 holds a list of ASSERT_LOCUS_T nodes that describe where
138 ASSERT_EXPRs for SSA name N_I should be inserted. */
139 static assert_locus_t *asserts_for;
141 /* Value range array. After propagation, VR_VALUE[I] holds the range
142 of values that SSA name N_I may take. */
143 static unsigned num_vr_values;
144 static value_range_t **vr_value;
145 static bool values_propagated;
147 /* For a PHI node which sets SSA name N_I, VR_COUNTS[I] holds the
148 number of executable edges we saw the last time we visited the
150 static int *vr_phi_edge_counts;
157 static VEC (edge, heap) *to_remove_edges;
158 DEF_VEC_O(switch_update);
159 DEF_VEC_ALLOC_O(switch_update, heap);
160 static VEC (switch_update, heap) *to_update_switch_stmts;
163 /* Return the maximum value for TYPE. */
166 vrp_val_max (const_tree type)
168 if (!INTEGRAL_TYPE_P (type))
171 return TYPE_MAX_VALUE (type);
174 /* Return the minimum value for TYPE. */
177 vrp_val_min (const_tree type)
179 if (!INTEGRAL_TYPE_P (type))
182 return TYPE_MIN_VALUE (type);
185 /* Return whether VAL is equal to the maximum value of its type. This
186 will be true for a positive overflow infinity. We can't do a
187 simple equality comparison with TYPE_MAX_VALUE because C typedefs
188 and Ada subtypes can produce types whose TYPE_MAX_VALUE is not ==
189 to the integer constant with the same value in the type. */
192 vrp_val_is_max (const_tree val)
194 tree type_max = vrp_val_max (TREE_TYPE (val));
195 return (val == type_max
196 || (type_max != NULL_TREE
197 && operand_equal_p (val, type_max, 0)));
200 /* Return whether VAL is equal to the minimum value of its type. This
201 will be true for a negative overflow infinity. */
204 vrp_val_is_min (const_tree val)
206 tree type_min = vrp_val_min (TREE_TYPE (val));
207 return (val == type_min
208 || (type_min != NULL_TREE
209 && operand_equal_p (val, type_min, 0)));
213 /* Return whether TYPE should use an overflow infinity distinct from
214 TYPE_{MIN,MAX}_VALUE. We use an overflow infinity value to
215 represent a signed overflow during VRP computations. An infinity
216 is distinct from a half-range, which will go from some number to
217 TYPE_{MIN,MAX}_VALUE. */
220 needs_overflow_infinity (const_tree type)
222 return INTEGRAL_TYPE_P (type) && !TYPE_OVERFLOW_WRAPS (type);
225 /* Return whether TYPE can support our overflow infinity
226 representation: we use the TREE_OVERFLOW flag, which only exists
227 for constants. If TYPE doesn't support this, we don't optimize
228 cases which would require signed overflow--we drop them to
232 supports_overflow_infinity (const_tree type)
234 tree min = vrp_val_min (type), max = vrp_val_max (type);
235 #ifdef ENABLE_CHECKING
236 gcc_assert (needs_overflow_infinity (type));
238 return (min != NULL_TREE
239 && CONSTANT_CLASS_P (min)
241 && CONSTANT_CLASS_P (max));
244 /* VAL is the maximum or minimum value of a type. Return a
245 corresponding overflow infinity. */
248 make_overflow_infinity (tree val)
250 gcc_checking_assert (val != NULL_TREE && CONSTANT_CLASS_P (val));
251 val = copy_node (val);
252 TREE_OVERFLOW (val) = 1;
256 /* Return a negative overflow infinity for TYPE. */
259 negative_overflow_infinity (tree type)
261 gcc_checking_assert (supports_overflow_infinity (type));
262 return make_overflow_infinity (vrp_val_min (type));
265 /* Return a positive overflow infinity for TYPE. */
268 positive_overflow_infinity (tree type)
270 gcc_checking_assert (supports_overflow_infinity (type));
271 return make_overflow_infinity (vrp_val_max (type));
274 /* Return whether VAL is a negative overflow infinity. */
277 is_negative_overflow_infinity (const_tree val)
279 return (needs_overflow_infinity (TREE_TYPE (val))
280 && CONSTANT_CLASS_P (val)
281 && TREE_OVERFLOW (val)
282 && vrp_val_is_min (val));
285 /* Return whether VAL is a positive overflow infinity. */
288 is_positive_overflow_infinity (const_tree val)
290 return (needs_overflow_infinity (TREE_TYPE (val))
291 && CONSTANT_CLASS_P (val)
292 && TREE_OVERFLOW (val)
293 && vrp_val_is_max (val));
296 /* Return whether VAL is a positive or negative overflow infinity. */
299 is_overflow_infinity (const_tree val)
301 return (needs_overflow_infinity (TREE_TYPE (val))
302 && CONSTANT_CLASS_P (val)
303 && TREE_OVERFLOW (val)
304 && (vrp_val_is_min (val) || vrp_val_is_max (val)));
307 /* Return whether STMT has a constant rhs that is_overflow_infinity. */
310 stmt_overflow_infinity (gimple stmt)
312 if (is_gimple_assign (stmt)
313 && get_gimple_rhs_class (gimple_assign_rhs_code (stmt)) ==
315 return is_overflow_infinity (gimple_assign_rhs1 (stmt));
319 /* If VAL is now an overflow infinity, return VAL. Otherwise, return
320 the same value with TREE_OVERFLOW clear. This can be used to avoid
321 confusing a regular value with an overflow value. */
324 avoid_overflow_infinity (tree val)
326 if (!is_overflow_infinity (val))
329 if (vrp_val_is_max (val))
330 return vrp_val_max (TREE_TYPE (val));
333 gcc_checking_assert (vrp_val_is_min (val));
334 return vrp_val_min (TREE_TYPE (val));
339 /* Return true if ARG is marked with the nonnull attribute in the
340 current function signature. */
343 nonnull_arg_p (const_tree arg)
345 tree t, attrs, fntype;
346 unsigned HOST_WIDE_INT arg_num;
348 gcc_assert (TREE_CODE (arg) == PARM_DECL && POINTER_TYPE_P (TREE_TYPE (arg)));
350 /* The static chain decl is always non null. */
351 if (arg == cfun->static_chain_decl)
354 fntype = TREE_TYPE (current_function_decl);
355 attrs = lookup_attribute ("nonnull", TYPE_ATTRIBUTES (fntype));
357 /* If "nonnull" wasn't specified, we know nothing about the argument. */
358 if (attrs == NULL_TREE)
361 /* If "nonnull" applies to all the arguments, then ARG is non-null. */
362 if (TREE_VALUE (attrs) == NULL_TREE)
365 /* Get the position number for ARG in the function signature. */
366 for (arg_num = 1, t = DECL_ARGUMENTS (current_function_decl);
368 t = DECL_CHAIN (t), arg_num++)
374 gcc_assert (t == arg);
376 /* Now see if ARG_NUM is mentioned in the nonnull list. */
377 for (t = TREE_VALUE (attrs); t; t = TREE_CHAIN (t))
379 if (compare_tree_int (TREE_VALUE (t), arg_num) == 0)
387 /* Set value range VR to VR_VARYING. */
390 set_value_range_to_varying (value_range_t *vr)
392 vr->type = VR_VARYING;
393 vr->min = vr->max = NULL_TREE;
395 bitmap_clear (vr->equiv);
399 /* Set value range VR to {T, MIN, MAX, EQUIV}. */
402 set_value_range (value_range_t *vr, enum value_range_type t, tree min,
403 tree max, bitmap equiv)
405 #if defined ENABLE_CHECKING
406 /* Check the validity of the range. */
407 if (t == VR_RANGE || t == VR_ANTI_RANGE)
411 gcc_assert (min && max);
413 if (INTEGRAL_TYPE_P (TREE_TYPE (min)) && t == VR_ANTI_RANGE)
414 gcc_assert (!vrp_val_is_min (min) || !vrp_val_is_max (max));
416 cmp = compare_values (min, max);
417 gcc_assert (cmp == 0 || cmp == -1 || cmp == -2);
419 if (needs_overflow_infinity (TREE_TYPE (min)))
420 gcc_assert (!is_overflow_infinity (min)
421 || !is_overflow_infinity (max));
424 if (t == VR_UNDEFINED || t == VR_VARYING)
425 gcc_assert (min == NULL_TREE && max == NULL_TREE);
427 if (t == VR_UNDEFINED || t == VR_VARYING)
428 gcc_assert (equiv == NULL || bitmap_empty_p (equiv));
435 /* Since updating the equivalence set involves deep copying the
436 bitmaps, only do it if absolutely necessary. */
437 if (vr->equiv == NULL
439 vr->equiv = BITMAP_ALLOC (NULL);
441 if (equiv != vr->equiv)
443 if (equiv && !bitmap_empty_p (equiv))
444 bitmap_copy (vr->equiv, equiv);
446 bitmap_clear (vr->equiv);
451 /* Set value range VR to the canonical form of {T, MIN, MAX, EQUIV}.
452 This means adjusting T, MIN and MAX representing the case of a
453 wrapping range with MAX < MIN covering [MIN, type_max] U [type_min, MAX]
454 as anti-rage ~[MAX+1, MIN-1]. Likewise for wrapping anti-ranges.
455 In corner cases where MAX+1 or MIN-1 wraps this will fall back
457 This routine exists to ease canonicalization in the case where we
458 extract ranges from var + CST op limit. */
461 set_and_canonicalize_value_range (value_range_t *vr, enum value_range_type t,
462 tree min, tree max, bitmap equiv)
464 /* Nothing to canonicalize for symbolic or unknown or varying ranges. */
466 && t != VR_ANTI_RANGE)
467 || TREE_CODE (min) != INTEGER_CST
468 || TREE_CODE (max) != INTEGER_CST)
470 set_value_range (vr, t, min, max, equiv);
474 /* Wrong order for min and max, to swap them and the VR type we need
476 if (tree_int_cst_lt (max, min))
478 tree one = build_int_cst (TREE_TYPE (min), 1);
479 tree tmp = int_const_binop (PLUS_EXPR, max, one);
480 max = int_const_binop (MINUS_EXPR, min, one);
483 /* There's one corner case, if we had [C+1, C] before we now have
484 that again. But this represents an empty value range, so drop
485 to varying in this case. */
486 if (tree_int_cst_lt (max, min))
488 set_value_range_to_varying (vr);
492 t = t == VR_RANGE ? VR_ANTI_RANGE : VR_RANGE;
495 /* Anti-ranges that can be represented as ranges should be so. */
496 if (t == VR_ANTI_RANGE)
498 bool is_min = vrp_val_is_min (min);
499 bool is_max = vrp_val_is_max (max);
501 if (is_min && is_max)
503 /* We cannot deal with empty ranges, drop to varying. */
504 set_value_range_to_varying (vr);
508 /* As a special exception preserve non-null ranges. */
509 && !(TYPE_UNSIGNED (TREE_TYPE (min))
510 && integer_zerop (max)))
512 tree one = build_int_cst (TREE_TYPE (max), 1);
513 min = int_const_binop (PLUS_EXPR, max, one);
514 max = vrp_val_max (TREE_TYPE (max));
519 tree one = build_int_cst (TREE_TYPE (min), 1);
520 max = int_const_binop (MINUS_EXPR, min, one);
521 min = vrp_val_min (TREE_TYPE (min));
526 set_value_range (vr, t, min, max, equiv);
529 /* Copy value range FROM into value range TO. */
532 copy_value_range (value_range_t *to, value_range_t *from)
534 set_value_range (to, from->type, from->min, from->max, from->equiv);
537 /* Set value range VR to a single value. This function is only called
538 with values we get from statements, and exists to clear the
539 TREE_OVERFLOW flag so that we don't think we have an overflow
540 infinity when we shouldn't. */
543 set_value_range_to_value (value_range_t *vr, tree val, bitmap equiv)
545 gcc_assert (is_gimple_min_invariant (val));
546 val = avoid_overflow_infinity (val);
547 set_value_range (vr, VR_RANGE, val, val, equiv);
550 /* Set value range VR to a non-negative range of type TYPE.
551 OVERFLOW_INFINITY indicates whether to use an overflow infinity
552 rather than TYPE_MAX_VALUE; this should be true if we determine
553 that the range is nonnegative based on the assumption that signed
554 overflow does not occur. */
557 set_value_range_to_nonnegative (value_range_t *vr, tree type,
558 bool overflow_infinity)
562 if (overflow_infinity && !supports_overflow_infinity (type))
564 set_value_range_to_varying (vr);
568 zero = build_int_cst (type, 0);
569 set_value_range (vr, VR_RANGE, zero,
571 ? positive_overflow_infinity (type)
572 : TYPE_MAX_VALUE (type)),
576 /* Set value range VR to a non-NULL range of type TYPE. */
579 set_value_range_to_nonnull (value_range_t *vr, tree type)
581 tree zero = build_int_cst (type, 0);
582 set_value_range (vr, VR_ANTI_RANGE, zero, zero, vr->equiv);
586 /* Set value range VR to a NULL range of type TYPE. */
589 set_value_range_to_null (value_range_t *vr, tree type)
591 set_value_range_to_value (vr, build_int_cst (type, 0), vr->equiv);
595 /* Set value range VR to a range of a truthvalue of type TYPE. */
598 set_value_range_to_truthvalue (value_range_t *vr, tree type)
600 if (TYPE_PRECISION (type) == 1)
601 set_value_range_to_varying (vr);
603 set_value_range (vr, VR_RANGE,
604 build_int_cst (type, 0), build_int_cst (type, 1),
609 /* Set value range VR to VR_UNDEFINED. */
612 set_value_range_to_undefined (value_range_t *vr)
614 vr->type = VR_UNDEFINED;
615 vr->min = vr->max = NULL_TREE;
617 bitmap_clear (vr->equiv);
621 /* If abs (min) < abs (max), set VR to [-max, max], if
622 abs (min) >= abs (max), set VR to [-min, min]. */
625 abs_extent_range (value_range_t *vr, tree min, tree max)
629 gcc_assert (TREE_CODE (min) == INTEGER_CST);
630 gcc_assert (TREE_CODE (max) == INTEGER_CST);
631 gcc_assert (INTEGRAL_TYPE_P (TREE_TYPE (min)));
632 gcc_assert (!TYPE_UNSIGNED (TREE_TYPE (min)));
633 min = fold_unary (ABS_EXPR, TREE_TYPE (min), min);
634 max = fold_unary (ABS_EXPR, TREE_TYPE (max), max);
635 if (TREE_OVERFLOW (min) || TREE_OVERFLOW (max))
637 set_value_range_to_varying (vr);
640 cmp = compare_values (min, max);
642 min = fold_unary (NEGATE_EXPR, TREE_TYPE (min), max);
643 else if (cmp == 0 || cmp == 1)
646 min = fold_unary (NEGATE_EXPR, TREE_TYPE (min), min);
650 set_value_range_to_varying (vr);
653 set_and_canonicalize_value_range (vr, VR_RANGE, min, max, NULL);
657 /* Return value range information for VAR.
659 If we have no values ranges recorded (ie, VRP is not running), then
660 return NULL. Otherwise create an empty range if none existed for VAR. */
662 static value_range_t *
663 get_value_range (const_tree var)
665 static const struct value_range_d vr_const_varying
666 = { VR_VARYING, NULL_TREE, NULL_TREE, NULL };
669 unsigned ver = SSA_NAME_VERSION (var);
671 /* If we have no recorded ranges, then return NULL. */
675 /* If we query the range for a new SSA name return an unmodifiable VARYING.
676 We should get here at most from the substitute-and-fold stage which
677 will never try to change values. */
678 if (ver >= num_vr_values)
679 return CONST_CAST (value_range_t *, &vr_const_varying);
685 /* After propagation finished do not allocate new value-ranges. */
686 if (values_propagated)
687 return CONST_CAST (value_range_t *, &vr_const_varying);
689 /* Create a default value range. */
690 vr_value[ver] = vr = XCNEW (value_range_t);
692 /* Defer allocating the equivalence set. */
695 /* If VAR is a default definition of a parameter, the variable can
696 take any value in VAR's type. */
697 sym = SSA_NAME_VAR (var);
698 if (SSA_NAME_IS_DEFAULT_DEF (var)
699 && TREE_CODE (sym) == PARM_DECL)
701 /* Try to use the "nonnull" attribute to create ~[0, 0]
702 anti-ranges for pointers. Note that this is only valid with
703 default definitions of PARM_DECLs. */
704 if (POINTER_TYPE_P (TREE_TYPE (sym))
705 && nonnull_arg_p (sym))
706 set_value_range_to_nonnull (vr, TREE_TYPE (sym));
708 set_value_range_to_varying (vr);
714 /* Return true, if VAL1 and VAL2 are equal values for VRP purposes. */
717 vrp_operand_equal_p (const_tree val1, const_tree val2)
721 if (!val1 || !val2 || !operand_equal_p (val1, val2, 0))
723 if (is_overflow_infinity (val1))
724 return is_overflow_infinity (val2);
728 /* Return true, if the bitmaps B1 and B2 are equal. */
731 vrp_bitmap_equal_p (const_bitmap b1, const_bitmap b2)
734 || ((!b1 || bitmap_empty_p (b1))
735 && (!b2 || bitmap_empty_p (b2)))
737 && bitmap_equal_p (b1, b2)));
740 /* Update the value range and equivalence set for variable VAR to
741 NEW_VR. Return true if NEW_VR is different from VAR's previous
744 NOTE: This function assumes that NEW_VR is a temporary value range
745 object created for the sole purpose of updating VAR's range. The
746 storage used by the equivalence set from NEW_VR will be freed by
747 this function. Do not call update_value_range when NEW_VR
748 is the range object associated with another SSA name. */
751 update_value_range (const_tree var, value_range_t *new_vr)
753 value_range_t *old_vr;
756 /* Update the value range, if necessary. */
757 old_vr = get_value_range (var);
758 is_new = old_vr->type != new_vr->type
759 || !vrp_operand_equal_p (old_vr->min, new_vr->min)
760 || !vrp_operand_equal_p (old_vr->max, new_vr->max)
761 || !vrp_bitmap_equal_p (old_vr->equiv, new_vr->equiv);
764 set_value_range (old_vr, new_vr->type, new_vr->min, new_vr->max,
767 BITMAP_FREE (new_vr->equiv);
773 /* Add VAR and VAR's equivalence set to EQUIV. This is the central
774 point where equivalence processing can be turned on/off. */
777 add_equivalence (bitmap *equiv, const_tree var)
779 unsigned ver = SSA_NAME_VERSION (var);
780 value_range_t *vr = vr_value[ver];
783 *equiv = BITMAP_ALLOC (NULL);
784 bitmap_set_bit (*equiv, ver);
786 bitmap_ior_into (*equiv, vr->equiv);
790 /* Return true if VR is ~[0, 0]. */
793 range_is_nonnull (value_range_t *vr)
795 return vr->type == VR_ANTI_RANGE
796 && integer_zerop (vr->min)
797 && integer_zerop (vr->max);
801 /* Return true if VR is [0, 0]. */
804 range_is_null (value_range_t *vr)
806 return vr->type == VR_RANGE
807 && integer_zerop (vr->min)
808 && integer_zerop (vr->max);
811 /* Return true if max and min of VR are INTEGER_CST. It's not necessary
815 range_int_cst_p (value_range_t *vr)
817 return (vr->type == VR_RANGE
818 && TREE_CODE (vr->max) == INTEGER_CST
819 && TREE_CODE (vr->min) == INTEGER_CST
820 && !TREE_OVERFLOW (vr->max)
821 && !TREE_OVERFLOW (vr->min));
824 /* Return true if VR is a INTEGER_CST singleton. */
827 range_int_cst_singleton_p (value_range_t *vr)
829 return (range_int_cst_p (vr)
830 && tree_int_cst_equal (vr->min, vr->max));
833 /* Return true if value range VR involves at least one symbol. */
836 symbolic_range_p (value_range_t *vr)
838 return (!is_gimple_min_invariant (vr->min)
839 || !is_gimple_min_invariant (vr->max));
842 /* Return true if value range VR uses an overflow infinity. */
845 overflow_infinity_range_p (value_range_t *vr)
847 return (vr->type == VR_RANGE
848 && (is_overflow_infinity (vr->min)
849 || is_overflow_infinity (vr->max)));
852 /* Return false if we can not make a valid comparison based on VR;
853 this will be the case if it uses an overflow infinity and overflow
854 is not undefined (i.e., -fno-strict-overflow is in effect).
855 Otherwise return true, and set *STRICT_OVERFLOW_P to true if VR
856 uses an overflow infinity. */
859 usable_range_p (value_range_t *vr, bool *strict_overflow_p)
861 gcc_assert (vr->type == VR_RANGE);
862 if (is_overflow_infinity (vr->min))
864 *strict_overflow_p = true;
865 if (!TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (vr->min)))
868 if (is_overflow_infinity (vr->max))
870 *strict_overflow_p = true;
871 if (!TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (vr->max)))
878 /* Like tree_expr_nonnegative_warnv_p, but this function uses value
879 ranges obtained so far. */
882 vrp_expr_computes_nonnegative (tree expr, bool *strict_overflow_p)
884 return (tree_expr_nonnegative_warnv_p (expr, strict_overflow_p)
885 || (TREE_CODE (expr) == SSA_NAME
886 && ssa_name_nonnegative_p (expr)));
889 /* Return true if the result of assignment STMT is know to be non-negative.
890 If the return value is based on the assumption that signed overflow is
891 undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't change
892 *STRICT_OVERFLOW_P.*/
895 gimple_assign_nonnegative_warnv_p (gimple stmt, bool *strict_overflow_p)
897 enum tree_code code = gimple_assign_rhs_code (stmt);
898 switch (get_gimple_rhs_class (code))
900 case GIMPLE_UNARY_RHS:
901 return tree_unary_nonnegative_warnv_p (gimple_assign_rhs_code (stmt),
902 gimple_expr_type (stmt),
903 gimple_assign_rhs1 (stmt),
905 case GIMPLE_BINARY_RHS:
906 return tree_binary_nonnegative_warnv_p (gimple_assign_rhs_code (stmt),
907 gimple_expr_type (stmt),
908 gimple_assign_rhs1 (stmt),
909 gimple_assign_rhs2 (stmt),
911 case GIMPLE_TERNARY_RHS:
913 case GIMPLE_SINGLE_RHS:
914 return tree_single_nonnegative_warnv_p (gimple_assign_rhs1 (stmt),
916 case GIMPLE_INVALID_RHS:
923 /* Return true if return value of call STMT is know to be non-negative.
924 If the return value is based on the assumption that signed overflow is
925 undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't change
926 *STRICT_OVERFLOW_P.*/
929 gimple_call_nonnegative_warnv_p (gimple stmt, bool *strict_overflow_p)
931 tree arg0 = gimple_call_num_args (stmt) > 0 ?
932 gimple_call_arg (stmt, 0) : NULL_TREE;
933 tree arg1 = gimple_call_num_args (stmt) > 1 ?
934 gimple_call_arg (stmt, 1) : NULL_TREE;
936 return tree_call_nonnegative_warnv_p (gimple_expr_type (stmt),
937 gimple_call_fndecl (stmt),
943 /* Return true if STMT is know to to compute a non-negative value.
944 If the return value is based on the assumption that signed overflow is
945 undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't change
946 *STRICT_OVERFLOW_P.*/
949 gimple_stmt_nonnegative_warnv_p (gimple stmt, bool *strict_overflow_p)
951 switch (gimple_code (stmt))
954 return gimple_assign_nonnegative_warnv_p (stmt, strict_overflow_p);
956 return gimple_call_nonnegative_warnv_p (stmt, strict_overflow_p);
962 /* Return true if the result of assignment STMT is know to be non-zero.
963 If the return value is based on the assumption that signed overflow is
964 undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't change
965 *STRICT_OVERFLOW_P.*/
968 gimple_assign_nonzero_warnv_p (gimple stmt, bool *strict_overflow_p)
970 enum tree_code code = gimple_assign_rhs_code (stmt);
971 switch (get_gimple_rhs_class (code))
973 case GIMPLE_UNARY_RHS:
974 return tree_unary_nonzero_warnv_p (gimple_assign_rhs_code (stmt),
975 gimple_expr_type (stmt),
976 gimple_assign_rhs1 (stmt),
978 case GIMPLE_BINARY_RHS:
979 return tree_binary_nonzero_warnv_p (gimple_assign_rhs_code (stmt),
980 gimple_expr_type (stmt),
981 gimple_assign_rhs1 (stmt),
982 gimple_assign_rhs2 (stmt),
984 case GIMPLE_TERNARY_RHS:
986 case GIMPLE_SINGLE_RHS:
987 return tree_single_nonzero_warnv_p (gimple_assign_rhs1 (stmt),
989 case GIMPLE_INVALID_RHS:
996 /* Return true if STMT is know to to compute a non-zero value.
997 If the return value is based on the assumption that signed overflow is
998 undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't change
999 *STRICT_OVERFLOW_P.*/
1002 gimple_stmt_nonzero_warnv_p (gimple stmt, bool *strict_overflow_p)
1004 switch (gimple_code (stmt))
1007 return gimple_assign_nonzero_warnv_p (stmt, strict_overflow_p);
1009 return gimple_alloca_call_p (stmt);
1015 /* Like tree_expr_nonzero_warnv_p, but this function uses value ranges
1019 vrp_stmt_computes_nonzero (gimple stmt, bool *strict_overflow_p)
1021 if (gimple_stmt_nonzero_warnv_p (stmt, strict_overflow_p))
1024 /* If we have an expression of the form &X->a, then the expression
1025 is nonnull if X is nonnull. */
1026 if (is_gimple_assign (stmt)
1027 && gimple_assign_rhs_code (stmt) == ADDR_EXPR)
1029 tree expr = gimple_assign_rhs1 (stmt);
1030 tree base = get_base_address (TREE_OPERAND (expr, 0));
1032 if (base != NULL_TREE
1033 && TREE_CODE (base) == MEM_REF
1034 && TREE_CODE (TREE_OPERAND (base, 0)) == SSA_NAME)
1036 value_range_t *vr = get_value_range (TREE_OPERAND (base, 0));
1037 if (range_is_nonnull (vr))
1045 /* Returns true if EXPR is a valid value (as expected by compare_values) --
1046 a gimple invariant, or SSA_NAME +- CST. */
1049 valid_value_p (tree expr)
1051 if (TREE_CODE (expr) == SSA_NAME)
1054 if (TREE_CODE (expr) == PLUS_EXPR
1055 || TREE_CODE (expr) == MINUS_EXPR)
1056 return (TREE_CODE (TREE_OPERAND (expr, 0)) == SSA_NAME
1057 && TREE_CODE (TREE_OPERAND (expr, 1)) == INTEGER_CST);
1059 return is_gimple_min_invariant (expr);
1065 -2 if those are incomparable. */
1067 operand_less_p (tree val, tree val2)
1069 /* LT is folded faster than GE and others. Inline the common case. */
1070 if (TREE_CODE (val) == INTEGER_CST && TREE_CODE (val2) == INTEGER_CST)
1072 if (TYPE_UNSIGNED (TREE_TYPE (val)))
1073 return INT_CST_LT_UNSIGNED (val, val2);
1076 if (INT_CST_LT (val, val2))
1084 fold_defer_overflow_warnings ();
1086 tcmp = fold_binary_to_constant (LT_EXPR, boolean_type_node, val, val2);
1088 fold_undefer_and_ignore_overflow_warnings ();
1091 || TREE_CODE (tcmp) != INTEGER_CST)
1094 if (!integer_zerop (tcmp))
1098 /* val >= val2, not considering overflow infinity. */
1099 if (is_negative_overflow_infinity (val))
1100 return is_negative_overflow_infinity (val2) ? 0 : 1;
1101 else if (is_positive_overflow_infinity (val2))
1102 return is_positive_overflow_infinity (val) ? 0 : 1;
1107 /* Compare two values VAL1 and VAL2. Return
1109 -2 if VAL1 and VAL2 cannot be compared at compile-time,
1112 +1 if VAL1 > VAL2, and
1115 This is similar to tree_int_cst_compare but supports pointer values
1116 and values that cannot be compared at compile time.
1118 If STRICT_OVERFLOW_P is not NULL, then set *STRICT_OVERFLOW_P to
1119 true if the return value is only valid if we assume that signed
1120 overflow is undefined. */
1123 compare_values_warnv (tree val1, tree val2, bool *strict_overflow_p)
1128 /* Below we rely on the fact that VAL1 and VAL2 are both pointers or
1130 gcc_assert (POINTER_TYPE_P (TREE_TYPE (val1))
1131 == POINTER_TYPE_P (TREE_TYPE (val2)));
1132 /* Convert the two values into the same type. This is needed because
1133 sizetype causes sign extension even for unsigned types. */
1134 val2 = fold_convert (TREE_TYPE (val1), val2);
1135 STRIP_USELESS_TYPE_CONVERSION (val2);
1137 if ((TREE_CODE (val1) == SSA_NAME
1138 || TREE_CODE (val1) == PLUS_EXPR
1139 || TREE_CODE (val1) == MINUS_EXPR)
1140 && (TREE_CODE (val2) == SSA_NAME
1141 || TREE_CODE (val2) == PLUS_EXPR
1142 || TREE_CODE (val2) == MINUS_EXPR))
1144 tree n1, c1, n2, c2;
1145 enum tree_code code1, code2;
1147 /* If VAL1 and VAL2 are of the form 'NAME [+-] CST' or 'NAME',
1148 return -1 or +1 accordingly. If VAL1 and VAL2 don't use the
1149 same name, return -2. */
1150 if (TREE_CODE (val1) == SSA_NAME)
1158 code1 = TREE_CODE (val1);
1159 n1 = TREE_OPERAND (val1, 0);
1160 c1 = TREE_OPERAND (val1, 1);
1161 if (tree_int_cst_sgn (c1) == -1)
1163 if (is_negative_overflow_infinity (c1))
1165 c1 = fold_unary_to_constant (NEGATE_EXPR, TREE_TYPE (c1), c1);
1168 code1 = code1 == MINUS_EXPR ? PLUS_EXPR : MINUS_EXPR;
1172 if (TREE_CODE (val2) == SSA_NAME)
1180 code2 = TREE_CODE (val2);
1181 n2 = TREE_OPERAND (val2, 0);
1182 c2 = TREE_OPERAND (val2, 1);
1183 if (tree_int_cst_sgn (c2) == -1)
1185 if (is_negative_overflow_infinity (c2))
1187 c2 = fold_unary_to_constant (NEGATE_EXPR, TREE_TYPE (c2), c2);
1190 code2 = code2 == MINUS_EXPR ? PLUS_EXPR : MINUS_EXPR;
1194 /* Both values must use the same name. */
1198 if (code1 == SSA_NAME
1199 && code2 == SSA_NAME)
1203 /* If overflow is defined we cannot simplify more. */
1204 if (!TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (val1)))
1207 if (strict_overflow_p != NULL
1208 && (code1 == SSA_NAME || !TREE_NO_WARNING (val1))
1209 && (code2 == SSA_NAME || !TREE_NO_WARNING (val2)))
1210 *strict_overflow_p = true;
1212 if (code1 == SSA_NAME)
1214 if (code2 == PLUS_EXPR)
1215 /* NAME < NAME + CST */
1217 else if (code2 == MINUS_EXPR)
1218 /* NAME > NAME - CST */
1221 else if (code1 == PLUS_EXPR)
1223 if (code2 == SSA_NAME)
1224 /* NAME + CST > NAME */
1226 else if (code2 == PLUS_EXPR)
1227 /* NAME + CST1 > NAME + CST2, if CST1 > CST2 */
1228 return compare_values_warnv (c1, c2, strict_overflow_p);
1229 else if (code2 == MINUS_EXPR)
1230 /* NAME + CST1 > NAME - CST2 */
1233 else if (code1 == MINUS_EXPR)
1235 if (code2 == SSA_NAME)
1236 /* NAME - CST < NAME */
1238 else if (code2 == PLUS_EXPR)
1239 /* NAME - CST1 < NAME + CST2 */
1241 else if (code2 == MINUS_EXPR)
1242 /* NAME - CST1 > NAME - CST2, if CST1 < CST2. Notice that
1243 C1 and C2 are swapped in the call to compare_values. */
1244 return compare_values_warnv (c2, c1, strict_overflow_p);
1250 /* We cannot compare non-constants. */
1251 if (!is_gimple_min_invariant (val1) || !is_gimple_min_invariant (val2))
1254 if (!POINTER_TYPE_P (TREE_TYPE (val1)))
1256 /* We cannot compare overflowed values, except for overflow
1258 if (TREE_OVERFLOW (val1) || TREE_OVERFLOW (val2))
1260 if (strict_overflow_p != NULL)
1261 *strict_overflow_p = true;
1262 if (is_negative_overflow_infinity (val1))
1263 return is_negative_overflow_infinity (val2) ? 0 : -1;
1264 else if (is_negative_overflow_infinity (val2))
1266 else if (is_positive_overflow_infinity (val1))
1267 return is_positive_overflow_infinity (val2) ? 0 : 1;
1268 else if (is_positive_overflow_infinity (val2))
1273 return tree_int_cst_compare (val1, val2);
1279 /* First see if VAL1 and VAL2 are not the same. */
1280 if (val1 == val2 || operand_equal_p (val1, val2, 0))
1283 /* If VAL1 is a lower address than VAL2, return -1. */
1284 if (operand_less_p (val1, val2) == 1)
1287 /* If VAL1 is a higher address than VAL2, return +1. */
1288 if (operand_less_p (val2, val1) == 1)
1291 /* If VAL1 is different than VAL2, return +2.
1292 For integer constants we either have already returned -1 or 1
1293 or they are equivalent. We still might succeed in proving
1294 something about non-trivial operands. */
1295 if (TREE_CODE (val1) != INTEGER_CST
1296 || TREE_CODE (val2) != INTEGER_CST)
1298 t = fold_binary_to_constant (NE_EXPR, boolean_type_node, val1, val2);
1299 if (t && integer_onep (t))
1307 /* Compare values like compare_values_warnv, but treat comparisons of
1308 nonconstants which rely on undefined overflow as incomparable. */
1311 compare_values (tree val1, tree val2)
1317 ret = compare_values_warnv (val1, val2, &sop);
1319 && (!is_gimple_min_invariant (val1) || !is_gimple_min_invariant (val2)))
1325 /* Return 1 if VAL is inside value range VR (VR->MIN <= VAL <= VR->MAX),
1326 0 if VAL is not inside VR,
1327 -2 if we cannot tell either way.
1329 FIXME, the current semantics of this functions are a bit quirky
1330 when taken in the context of VRP. In here we do not care
1331 about VR's type. If VR is the anti-range ~[3, 5] the call
1332 value_inside_range (4, VR) will return 1.
1334 This is counter-intuitive in a strict sense, but the callers
1335 currently expect this. They are calling the function
1336 merely to determine whether VR->MIN <= VAL <= VR->MAX. The
1337 callers are applying the VR_RANGE/VR_ANTI_RANGE semantics
1340 This also applies to value_ranges_intersect_p and
1341 range_includes_zero_p. The semantics of VR_RANGE and
1342 VR_ANTI_RANGE should be encoded here, but that also means
1343 adapting the users of these functions to the new semantics.
1345 Benchmark compile/20001226-1.c compilation time after changing this
1349 value_inside_range (tree val, value_range_t * vr)
1353 cmp1 = operand_less_p (val, vr->min);
1359 cmp2 = operand_less_p (vr->max, val);
1367 /* Return true if value ranges VR0 and VR1 have a non-empty
1370 Benchmark compile/20001226-1.c compilation time after changing this
1375 value_ranges_intersect_p (value_range_t *vr0, value_range_t *vr1)
1377 /* The value ranges do not intersect if the maximum of the first range is
1378 less than the minimum of the second range or vice versa.
1379 When those relations are unknown, we can't do any better. */
1380 if (operand_less_p (vr0->max, vr1->min) != 0)
1382 if (operand_less_p (vr1->max, vr0->min) != 0)
1388 /* Return true if VR includes the value zero, false otherwise. FIXME,
1389 currently this will return false for an anti-range like ~[-4, 3].
1390 This will be wrong when the semantics of value_inside_range are
1391 modified (currently the users of this function expect these
1395 range_includes_zero_p (value_range_t *vr)
1399 gcc_assert (vr->type != VR_UNDEFINED
1400 && vr->type != VR_VARYING
1401 && !symbolic_range_p (vr));
1403 zero = build_int_cst (TREE_TYPE (vr->min), 0);
1404 return (value_inside_range (zero, vr) == 1);
1407 /* Return true if T, an SSA_NAME, is known to be nonnegative. Return
1408 false otherwise or if no value range information is available. */
1411 ssa_name_nonnegative_p (const_tree t)
1413 value_range_t *vr = get_value_range (t);
1415 if (INTEGRAL_TYPE_P (t)
1416 && TYPE_UNSIGNED (t))
1422 /* Testing for VR_ANTI_RANGE is not useful here as any anti-range
1423 which would return a useful value should be encoded as a VR_RANGE. */
1424 if (vr->type == VR_RANGE)
1426 int result = compare_values (vr->min, integer_zero_node);
1428 return (result == 0 || result == 1);
1433 /* If OP has a value range with a single constant value return that,
1434 otherwise return NULL_TREE. This returns OP itself if OP is a
1438 op_with_constant_singleton_value_range (tree op)
1442 if (is_gimple_min_invariant (op))
1445 if (TREE_CODE (op) != SSA_NAME)
1448 vr = get_value_range (op);
1449 if (vr->type == VR_RANGE
1450 && operand_equal_p (vr->min, vr->max, 0)
1451 && is_gimple_min_invariant (vr->min))
1457 /* Return true if op is in a boolean [0, 1] value-range. */
1460 op_with_boolean_value_range_p (tree op)
1464 if (TYPE_PRECISION (TREE_TYPE (op)) == 1)
1467 if (integer_zerop (op)
1468 || integer_onep (op))
1471 if (TREE_CODE (op) != SSA_NAME)
1474 vr = get_value_range (op);
1475 return (vr->type == VR_RANGE
1476 && integer_zerop (vr->min)
1477 && integer_onep (vr->max));
1480 /* Extract value range information from an ASSERT_EXPR EXPR and store
1484 extract_range_from_assert (value_range_t *vr_p, tree expr)
1486 tree var, cond, limit, min, max, type;
1487 value_range_t *var_vr, *limit_vr;
1488 enum tree_code cond_code;
1490 var = ASSERT_EXPR_VAR (expr);
1491 cond = ASSERT_EXPR_COND (expr);
1493 gcc_assert (COMPARISON_CLASS_P (cond));
1495 /* Find VAR in the ASSERT_EXPR conditional. */
1496 if (var == TREE_OPERAND (cond, 0)
1497 || TREE_CODE (TREE_OPERAND (cond, 0)) == PLUS_EXPR
1498 || TREE_CODE (TREE_OPERAND (cond, 0)) == NOP_EXPR)
1500 /* If the predicate is of the form VAR COMP LIMIT, then we just
1501 take LIMIT from the RHS and use the same comparison code. */
1502 cond_code = TREE_CODE (cond);
1503 limit = TREE_OPERAND (cond, 1);
1504 cond = TREE_OPERAND (cond, 0);
1508 /* If the predicate is of the form LIMIT COMP VAR, then we need
1509 to flip around the comparison code to create the proper range
1511 cond_code = swap_tree_comparison (TREE_CODE (cond));
1512 limit = TREE_OPERAND (cond, 0);
1513 cond = TREE_OPERAND (cond, 1);
1516 limit = avoid_overflow_infinity (limit);
1518 type = TREE_TYPE (limit);
1519 gcc_assert (limit != var);
1521 /* For pointer arithmetic, we only keep track of pointer equality
1523 if (POINTER_TYPE_P (type) && cond_code != NE_EXPR && cond_code != EQ_EXPR)
1525 set_value_range_to_varying (vr_p);
1529 /* If LIMIT is another SSA name and LIMIT has a range of its own,
1530 try to use LIMIT's range to avoid creating symbolic ranges
1532 limit_vr = (TREE_CODE (limit) == SSA_NAME) ? get_value_range (limit) : NULL;
1534 /* LIMIT's range is only interesting if it has any useful information. */
1536 && (limit_vr->type == VR_UNDEFINED
1537 || limit_vr->type == VR_VARYING
1538 || symbolic_range_p (limit_vr)))
1541 /* Initially, the new range has the same set of equivalences of
1542 VAR's range. This will be revised before returning the final
1543 value. Since assertions may be chained via mutually exclusive
1544 predicates, we will need to trim the set of equivalences before
1546 gcc_assert (vr_p->equiv == NULL);
1547 add_equivalence (&vr_p->equiv, var);
1549 /* Extract a new range based on the asserted comparison for VAR and
1550 LIMIT's value range. Notice that if LIMIT has an anti-range, we
1551 will only use it for equality comparisons (EQ_EXPR). For any
1552 other kind of assertion, we cannot derive a range from LIMIT's
1553 anti-range that can be used to describe the new range. For
1554 instance, ASSERT_EXPR <x_2, x_2 <= b_4>. If b_4 is ~[2, 10],
1555 then b_4 takes on the ranges [-INF, 1] and [11, +INF]. There is
1556 no single range for x_2 that could describe LE_EXPR, so we might
1557 as well build the range [b_4, +INF] for it.
1558 One special case we handle is extracting a range from a
1559 range test encoded as (unsigned)var + CST <= limit. */
1560 if (TREE_CODE (cond) == NOP_EXPR
1561 || TREE_CODE (cond) == PLUS_EXPR)
1563 if (TREE_CODE (cond) == PLUS_EXPR)
1565 min = fold_build1 (NEGATE_EXPR, TREE_TYPE (TREE_OPERAND (cond, 1)),
1566 TREE_OPERAND (cond, 1));
1567 max = int_const_binop (PLUS_EXPR, limit, min);
1568 cond = TREE_OPERAND (cond, 0);
1572 min = build_int_cst (TREE_TYPE (var), 0);
1576 /* Make sure to not set TREE_OVERFLOW on the final type
1577 conversion. We are willingly interpreting large positive
1578 unsigned values as negative singed values here. */
1579 min = force_fit_type_double (TREE_TYPE (var), tree_to_double_int (min),
1581 max = force_fit_type_double (TREE_TYPE (var), tree_to_double_int (max),
1584 /* We can transform a max, min range to an anti-range or
1585 vice-versa. Use set_and_canonicalize_value_range which does
1587 if (cond_code == LE_EXPR)
1588 set_and_canonicalize_value_range (vr_p, VR_RANGE,
1589 min, max, vr_p->equiv);
1590 else if (cond_code == GT_EXPR)
1591 set_and_canonicalize_value_range (vr_p, VR_ANTI_RANGE,
1592 min, max, vr_p->equiv);
1596 else if (cond_code == EQ_EXPR)
1598 enum value_range_type range_type;
1602 range_type = limit_vr->type;
1603 min = limit_vr->min;
1604 max = limit_vr->max;
1608 range_type = VR_RANGE;
1613 set_value_range (vr_p, range_type, min, max, vr_p->equiv);
1615 /* When asserting the equality VAR == LIMIT and LIMIT is another
1616 SSA name, the new range will also inherit the equivalence set
1618 if (TREE_CODE (limit) == SSA_NAME)
1619 add_equivalence (&vr_p->equiv, limit);
1621 else if (cond_code == NE_EXPR)
1623 /* As described above, when LIMIT's range is an anti-range and
1624 this assertion is an inequality (NE_EXPR), then we cannot
1625 derive anything from the anti-range. For instance, if
1626 LIMIT's range was ~[0, 0], the assertion 'VAR != LIMIT' does
1627 not imply that VAR's range is [0, 0]. So, in the case of
1628 anti-ranges, we just assert the inequality using LIMIT and
1631 If LIMIT_VR is a range, we can only use it to build a new
1632 anti-range if LIMIT_VR is a single-valued range. For
1633 instance, if LIMIT_VR is [0, 1], the predicate
1634 VAR != [0, 1] does not mean that VAR's range is ~[0, 1].
1635 Rather, it means that for value 0 VAR should be ~[0, 0]
1636 and for value 1, VAR should be ~[1, 1]. We cannot
1637 represent these ranges.
1639 The only situation in which we can build a valid
1640 anti-range is when LIMIT_VR is a single-valued range
1641 (i.e., LIMIT_VR->MIN == LIMIT_VR->MAX). In that case,
1642 build the anti-range ~[LIMIT_VR->MIN, LIMIT_VR->MAX]. */
1644 && limit_vr->type == VR_RANGE
1645 && compare_values (limit_vr->min, limit_vr->max) == 0)
1647 min = limit_vr->min;
1648 max = limit_vr->max;
1652 /* In any other case, we cannot use LIMIT's range to build a
1653 valid anti-range. */
1657 /* If MIN and MAX cover the whole range for their type, then
1658 just use the original LIMIT. */
1659 if (INTEGRAL_TYPE_P (type)
1660 && vrp_val_is_min (min)
1661 && vrp_val_is_max (max))
1664 set_value_range (vr_p, VR_ANTI_RANGE, min, max, vr_p->equiv);
1666 else if (cond_code == LE_EXPR || cond_code == LT_EXPR)
1668 min = TYPE_MIN_VALUE (type);
1670 if (limit_vr == NULL || limit_vr->type == VR_ANTI_RANGE)
1674 /* If LIMIT_VR is of the form [N1, N2], we need to build the
1675 range [MIN, N2] for LE_EXPR and [MIN, N2 - 1] for
1677 max = limit_vr->max;
1680 /* If the maximum value forces us to be out of bounds, simply punt.
1681 It would be pointless to try and do anything more since this
1682 all should be optimized away above us. */
1683 if ((cond_code == LT_EXPR
1684 && compare_values (max, min) == 0)
1685 || (CONSTANT_CLASS_P (max) && TREE_OVERFLOW (max)))
1686 set_value_range_to_varying (vr_p);
1689 /* For LT_EXPR, we create the range [MIN, MAX - 1]. */
1690 if (cond_code == LT_EXPR)
1692 tree one = build_int_cst (type, 1);
1693 max = fold_build2 (MINUS_EXPR, type, max, one);
1695 TREE_NO_WARNING (max) = 1;
1698 set_value_range (vr_p, VR_RANGE, min, max, vr_p->equiv);
1701 else if (cond_code == GE_EXPR || cond_code == GT_EXPR)
1703 max = TYPE_MAX_VALUE (type);
1705 if (limit_vr == NULL || limit_vr->type == VR_ANTI_RANGE)
1709 /* If LIMIT_VR is of the form [N1, N2], we need to build the
1710 range [N1, MAX] for GE_EXPR and [N1 + 1, MAX] for
1712 min = limit_vr->min;
1715 /* If the minimum value forces us to be out of bounds, simply punt.
1716 It would be pointless to try and do anything more since this
1717 all should be optimized away above us. */
1718 if ((cond_code == GT_EXPR
1719 && compare_values (min, max) == 0)
1720 || (CONSTANT_CLASS_P (min) && TREE_OVERFLOW (min)))
1721 set_value_range_to_varying (vr_p);
1724 /* For GT_EXPR, we create the range [MIN + 1, MAX]. */
1725 if (cond_code == GT_EXPR)
1727 tree one = build_int_cst (type, 1);
1728 min = fold_build2 (PLUS_EXPR, type, min, one);
1730 TREE_NO_WARNING (min) = 1;
1733 set_value_range (vr_p, VR_RANGE, min, max, vr_p->equiv);
1739 /* If VAR already had a known range, it may happen that the new
1740 range we have computed and VAR's range are not compatible. For
1744 p_6 = ASSERT_EXPR <p_5, p_5 == NULL>;
1746 p_8 = ASSERT_EXPR <p_6, p_6 != NULL>;
1748 While the above comes from a faulty program, it will cause an ICE
1749 later because p_8 and p_6 will have incompatible ranges and at
1750 the same time will be considered equivalent. A similar situation
1754 i_6 = ASSERT_EXPR <i_5, i_5 > 10>;
1756 i_7 = ASSERT_EXPR <i_6, i_6 < 5>;
1758 Again i_6 and i_7 will have incompatible ranges. It would be
1759 pointless to try and do anything with i_7's range because
1760 anything dominated by 'if (i_5 < 5)' will be optimized away.
1761 Note, due to the wa in which simulation proceeds, the statement
1762 i_7 = ASSERT_EXPR <...> we would never be visited because the
1763 conditional 'if (i_5 < 5)' always evaluates to false. However,
1764 this extra check does not hurt and may protect against future
1765 changes to VRP that may get into a situation similar to the
1766 NULL pointer dereference example.
1768 Note that these compatibility tests are only needed when dealing
1769 with ranges or a mix of range and anti-range. If VAR_VR and VR_P
1770 are both anti-ranges, they will always be compatible, because two
1771 anti-ranges will always have a non-empty intersection. */
1773 var_vr = get_value_range (var);
1775 /* We may need to make adjustments when VR_P and VAR_VR are numeric
1776 ranges or anti-ranges. */
1777 if (vr_p->type == VR_VARYING
1778 || vr_p->type == VR_UNDEFINED
1779 || var_vr->type == VR_VARYING
1780 || var_vr->type == VR_UNDEFINED
1781 || symbolic_range_p (vr_p)
1782 || symbolic_range_p (var_vr))
1785 if (var_vr->type == VR_RANGE && vr_p->type == VR_RANGE)
1787 /* If the two ranges have a non-empty intersection, we can
1788 refine the resulting range. Since the assert expression
1789 creates an equivalency and at the same time it asserts a
1790 predicate, we can take the intersection of the two ranges to
1791 get better precision. */
1792 if (value_ranges_intersect_p (var_vr, vr_p))
1794 /* Use the larger of the two minimums. */
1795 if (compare_values (vr_p->min, var_vr->min) == -1)
1800 /* Use the smaller of the two maximums. */
1801 if (compare_values (vr_p->max, var_vr->max) == 1)
1806 set_value_range (vr_p, vr_p->type, min, max, vr_p->equiv);
1810 /* The two ranges do not intersect, set the new range to
1811 VARYING, because we will not be able to do anything
1812 meaningful with it. */
1813 set_value_range_to_varying (vr_p);
1816 else if ((var_vr->type == VR_RANGE && vr_p->type == VR_ANTI_RANGE)
1817 || (var_vr->type == VR_ANTI_RANGE && vr_p->type == VR_RANGE))
1819 /* A range and an anti-range will cancel each other only if
1820 their ends are the same. For instance, in the example above,
1821 p_8's range ~[0, 0] and p_6's range [0, 0] are incompatible,
1822 so VR_P should be set to VR_VARYING. */
1823 if (compare_values (var_vr->min, vr_p->min) == 0
1824 && compare_values (var_vr->max, vr_p->max) == 0)
1825 set_value_range_to_varying (vr_p);
1828 tree min, max, anti_min, anti_max, real_min, real_max;
1831 /* We want to compute the logical AND of the two ranges;
1832 there are three cases to consider.
1835 1. The VR_ANTI_RANGE range is completely within the
1836 VR_RANGE and the endpoints of the ranges are
1837 different. In that case the resulting range
1838 should be whichever range is more precise.
1839 Typically that will be the VR_RANGE.
1841 2. The VR_ANTI_RANGE is completely disjoint from
1842 the VR_RANGE. In this case the resulting range
1843 should be the VR_RANGE.
1845 3. There is some overlap between the VR_ANTI_RANGE
1848 3a. If the high limit of the VR_ANTI_RANGE resides
1849 within the VR_RANGE, then the result is a new
1850 VR_RANGE starting at the high limit of the
1851 VR_ANTI_RANGE + 1 and extending to the
1852 high limit of the original VR_RANGE.
1854 3b. If the low limit of the VR_ANTI_RANGE resides
1855 within the VR_RANGE, then the result is a new
1856 VR_RANGE starting at the low limit of the original
1857 VR_RANGE and extending to the low limit of the
1858 VR_ANTI_RANGE - 1. */
1859 if (vr_p->type == VR_ANTI_RANGE)
1861 anti_min = vr_p->min;
1862 anti_max = vr_p->max;
1863 real_min = var_vr->min;
1864 real_max = var_vr->max;
1868 anti_min = var_vr->min;
1869 anti_max = var_vr->max;
1870 real_min = vr_p->min;
1871 real_max = vr_p->max;
1875 /* Case 1, VR_ANTI_RANGE completely within VR_RANGE,
1876 not including any endpoints. */
1877 if (compare_values (anti_max, real_max) == -1
1878 && compare_values (anti_min, real_min) == 1)
1880 /* If the range is covering the whole valid range of
1881 the type keep the anti-range. */
1882 if (!vrp_val_is_min (real_min)
1883 || !vrp_val_is_max (real_max))
1884 set_value_range (vr_p, VR_RANGE, real_min,
1885 real_max, vr_p->equiv);
1887 /* Case 2, VR_ANTI_RANGE completely disjoint from
1889 else if (compare_values (anti_min, real_max) == 1
1890 || compare_values (anti_max, real_min) == -1)
1892 set_value_range (vr_p, VR_RANGE, real_min,
1893 real_max, vr_p->equiv);
1895 /* Case 3a, the anti-range extends into the low
1896 part of the real range. Thus creating a new
1897 low for the real range. */
1898 else if (((cmp = compare_values (anti_max, real_min)) == 1
1900 && compare_values (anti_max, real_max) == -1)
1902 gcc_assert (!is_positive_overflow_infinity (anti_max));
1903 if (needs_overflow_infinity (TREE_TYPE (anti_max))
1904 && vrp_val_is_max (anti_max))
1906 if (!supports_overflow_infinity (TREE_TYPE (var_vr->min)))
1908 set_value_range_to_varying (vr_p);
1911 min = positive_overflow_infinity (TREE_TYPE (var_vr->min));
1913 else if (!POINTER_TYPE_P (TREE_TYPE (var_vr->min)))
1914 min = fold_build2 (PLUS_EXPR, TREE_TYPE (var_vr->min),
1916 build_int_cst (TREE_TYPE (var_vr->min), 1));
1918 min = fold_build_pointer_plus_hwi (anti_max, 1);
1920 set_value_range (vr_p, VR_RANGE, min, max, vr_p->equiv);
1922 /* Case 3b, the anti-range extends into the high
1923 part of the real range. Thus creating a new
1924 higher for the real range. */
1925 else if (compare_values (anti_min, real_min) == 1
1926 && ((cmp = compare_values (anti_min, real_max)) == -1
1929 gcc_assert (!is_negative_overflow_infinity (anti_min));
1930 if (needs_overflow_infinity (TREE_TYPE (anti_min))
1931 && vrp_val_is_min (anti_min))
1933 if (!supports_overflow_infinity (TREE_TYPE (var_vr->min)))
1935 set_value_range_to_varying (vr_p);
1938 max = negative_overflow_infinity (TREE_TYPE (var_vr->min));
1940 else if (!POINTER_TYPE_P (TREE_TYPE (var_vr->min)))
1941 max = fold_build2 (MINUS_EXPR, TREE_TYPE (var_vr->min),
1943 build_int_cst (TREE_TYPE (var_vr->min), 1));
1945 max = fold_build_pointer_plus_hwi (anti_min, -1);
1947 set_value_range (vr_p, VR_RANGE, min, max, vr_p->equiv);
1954 /* Extract range information from SSA name VAR and store it in VR. If
1955 VAR has an interesting range, use it. Otherwise, create the
1956 range [VAR, VAR] and return it. This is useful in situations where
1957 we may have conditionals testing values of VARYING names. For
1964 Even if y_5 is deemed VARYING, we can determine that x_3 > y_5 is
1968 extract_range_from_ssa_name (value_range_t *vr, tree var)
1970 value_range_t *var_vr = get_value_range (var);
1972 if (var_vr->type != VR_UNDEFINED && var_vr->type != VR_VARYING)
1973 copy_value_range (vr, var_vr);
1975 set_value_range (vr, VR_RANGE, var, var, NULL);
1977 add_equivalence (&vr->equiv, var);
1981 /* Wrapper around int_const_binop. If the operation overflows and we
1982 are not using wrapping arithmetic, then adjust the result to be
1983 -INF or +INF depending on CODE, VAL1 and VAL2. This can return
1984 NULL_TREE if we need to use an overflow infinity representation but
1985 the type does not support it. */
1988 vrp_int_const_binop (enum tree_code code, tree val1, tree val2)
1992 res = int_const_binop (code, val1, val2);
1994 /* If we are using unsigned arithmetic, operate symbolically
1995 on -INF and +INF as int_const_binop only handles signed overflow. */
1996 if (TYPE_UNSIGNED (TREE_TYPE (val1)))
1998 int checkz = compare_values (res, val1);
1999 bool overflow = false;
2001 /* Ensure that res = val1 [+*] val2 >= val1
2002 or that res = val1 - val2 <= val1. */
2003 if ((code == PLUS_EXPR
2004 && !(checkz == 1 || checkz == 0))
2005 || (code == MINUS_EXPR
2006 && !(checkz == 0 || checkz == -1)))
2010 /* Checking for multiplication overflow is done by dividing the
2011 output of the multiplication by the first input of the
2012 multiplication. If the result of that division operation is
2013 not equal to the second input of the multiplication, then the
2014 multiplication overflowed. */
2015 else if (code == MULT_EXPR && !integer_zerop (val1))
2017 tree tmp = int_const_binop (TRUNC_DIV_EXPR,
2020 int check = compare_values (tmp, val2);
2028 res = copy_node (res);
2029 TREE_OVERFLOW (res) = 1;
2033 else if (TYPE_OVERFLOW_WRAPS (TREE_TYPE (val1)))
2034 /* If the singed operation wraps then int_const_binop has done
2035 everything we want. */
2037 else if ((TREE_OVERFLOW (res)
2038 && !TREE_OVERFLOW (val1)
2039 && !TREE_OVERFLOW (val2))
2040 || is_overflow_infinity (val1)
2041 || is_overflow_infinity (val2))
2043 /* If the operation overflowed but neither VAL1 nor VAL2 are
2044 overflown, return -INF or +INF depending on the operation
2045 and the combination of signs of the operands. */
2046 int sgn1 = tree_int_cst_sgn (val1);
2047 int sgn2 = tree_int_cst_sgn (val2);
2049 if (needs_overflow_infinity (TREE_TYPE (res))
2050 && !supports_overflow_infinity (TREE_TYPE (res)))
2053 /* We have to punt on adding infinities of different signs,
2054 since we can't tell what the sign of the result should be.
2055 Likewise for subtracting infinities of the same sign. */
2056 if (((code == PLUS_EXPR && sgn1 != sgn2)
2057 || (code == MINUS_EXPR && sgn1 == sgn2))
2058 && is_overflow_infinity (val1)
2059 && is_overflow_infinity (val2))
2062 /* Don't try to handle division or shifting of infinities. */
2063 if ((code == TRUNC_DIV_EXPR
2064 || code == FLOOR_DIV_EXPR
2065 || code == CEIL_DIV_EXPR
2066 || code == EXACT_DIV_EXPR
2067 || code == ROUND_DIV_EXPR
2068 || code == RSHIFT_EXPR)
2069 && (is_overflow_infinity (val1)
2070 || is_overflow_infinity (val2)))
2073 /* Notice that we only need to handle the restricted set of
2074 operations handled by extract_range_from_binary_expr.
2075 Among them, only multiplication, addition and subtraction
2076 can yield overflow without overflown operands because we
2077 are working with integral types only... except in the
2078 case VAL1 = -INF and VAL2 = -1 which overflows to +INF
2079 for division too. */
2081 /* For multiplication, the sign of the overflow is given
2082 by the comparison of the signs of the operands. */
2083 if ((code == MULT_EXPR && sgn1 == sgn2)
2084 /* For addition, the operands must be of the same sign
2085 to yield an overflow. Its sign is therefore that
2086 of one of the operands, for example the first. For
2087 infinite operands X + -INF is negative, not positive. */
2088 || (code == PLUS_EXPR
2090 ? !is_negative_overflow_infinity (val2)
2091 : is_positive_overflow_infinity (val2)))
2092 /* For subtraction, non-infinite operands must be of
2093 different signs to yield an overflow. Its sign is
2094 therefore that of the first operand or the opposite of
2095 that of the second operand. A first operand of 0 counts
2096 as positive here, for the corner case 0 - (-INF), which
2097 overflows, but must yield +INF. For infinite operands 0
2098 - INF is negative, not positive. */
2099 || (code == MINUS_EXPR
2101 ? !is_positive_overflow_infinity (val2)
2102 : is_negative_overflow_infinity (val2)))
2103 /* We only get in here with positive shift count, so the
2104 overflow direction is the same as the sign of val1.
2105 Actually rshift does not overflow at all, but we only
2106 handle the case of shifting overflowed -INF and +INF. */
2107 || (code == RSHIFT_EXPR
2109 /* For division, the only case is -INF / -1 = +INF. */
2110 || code == TRUNC_DIV_EXPR
2111 || code == FLOOR_DIV_EXPR
2112 || code == CEIL_DIV_EXPR
2113 || code == EXACT_DIV_EXPR
2114 || code == ROUND_DIV_EXPR)
2115 return (needs_overflow_infinity (TREE_TYPE (res))
2116 ? positive_overflow_infinity (TREE_TYPE (res))
2117 : TYPE_MAX_VALUE (TREE_TYPE (res)));
2119 return (needs_overflow_infinity (TREE_TYPE (res))
2120 ? negative_overflow_infinity (TREE_TYPE (res))
2121 : TYPE_MIN_VALUE (TREE_TYPE (res)));
2128 /* For range VR compute two double_int bitmasks. In *MAY_BE_NONZERO
2129 bitmask if some bit is unset, it means for all numbers in the range
2130 the bit is 0, otherwise it might be 0 or 1. In *MUST_BE_NONZERO
2131 bitmask if some bit is set, it means for all numbers in the range
2132 the bit is 1, otherwise it might be 0 or 1. */
2135 zero_nonzero_bits_from_vr (value_range_t *vr, double_int *may_be_nonzero,
2136 double_int *must_be_nonzero)
2138 if (range_int_cst_p (vr))
2140 if (range_int_cst_singleton_p (vr))
2142 *may_be_nonzero = tree_to_double_int (vr->min);
2143 *must_be_nonzero = *may_be_nonzero;
2146 if (tree_int_cst_sgn (vr->min) >= 0)
2148 double_int dmin = tree_to_double_int (vr->min);
2149 double_int dmax = tree_to_double_int (vr->max);
2150 double_int xor_mask = double_int_xor (dmin, dmax);
2151 *may_be_nonzero = double_int_ior (dmin, dmax);
2152 *must_be_nonzero = double_int_and (dmin, dmax);
2153 if (xor_mask.high != 0)
2155 unsigned HOST_WIDE_INT mask
2156 = ((unsigned HOST_WIDE_INT) 1
2157 << floor_log2 (xor_mask.high)) - 1;
2158 may_be_nonzero->low = ALL_ONES;
2159 may_be_nonzero->high |= mask;
2160 must_be_nonzero->low = 0;
2161 must_be_nonzero->high &= ~mask;
2163 else if (xor_mask.low != 0)
2165 unsigned HOST_WIDE_INT mask
2166 = ((unsigned HOST_WIDE_INT) 1
2167 << floor_log2 (xor_mask.low)) - 1;
2168 may_be_nonzero->low |= mask;
2169 must_be_nonzero->low &= ~mask;
2174 may_be_nonzero->low = ALL_ONES;
2175 may_be_nonzero->high = ALL_ONES;
2176 must_be_nonzero->low = 0;
2177 must_be_nonzero->high = 0;
2182 /* Extract range information from a binary expression EXPR based on
2183 the ranges of each of its operands and the expression code. */
2186 extract_range_from_binary_expr (value_range_t *vr,
2187 enum tree_code code,
2188 tree expr_type, tree op0, tree op1)
2190 enum value_range_type type;
2193 value_range_t vr0 = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
2194 value_range_t vr1 = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
2196 /* Not all binary expressions can be applied to ranges in a
2197 meaningful way. Handle only arithmetic operations. */
2198 if (code != PLUS_EXPR
2199 && code != MINUS_EXPR
2200 && code != POINTER_PLUS_EXPR
2201 && code != MULT_EXPR
2202 && code != TRUNC_DIV_EXPR
2203 && code != FLOOR_DIV_EXPR
2204 && code != CEIL_DIV_EXPR
2205 && code != EXACT_DIV_EXPR
2206 && code != ROUND_DIV_EXPR
2207 && code != TRUNC_MOD_EXPR
2208 && code != RSHIFT_EXPR
2211 && code != BIT_AND_EXPR
2212 && code != BIT_IOR_EXPR)
2214 /* We can still do constant propagation here. */
2215 tree const_op0 = op_with_constant_singleton_value_range (op0);
2216 tree const_op1 = op_with_constant_singleton_value_range (op1);
2217 if (const_op0 || const_op1)
2219 tree tem = fold_binary (code, expr_type,
2220 const_op0 ? const_op0 : op0,
2221 const_op1 ? const_op1 : op1);
2223 && is_gimple_min_invariant (tem)
2224 && !is_overflow_infinity (tem))
2226 set_value_range (vr, VR_RANGE, tem, tem, NULL);
2230 set_value_range_to_varying (vr);
2234 /* Get value ranges for each operand. For constant operands, create
2235 a new value range with the operand to simplify processing. */
2236 if (TREE_CODE (op0) == SSA_NAME)
2237 vr0 = *(get_value_range (op0));
2238 else if (is_gimple_min_invariant (op0))
2239 set_value_range_to_value (&vr0, op0, NULL);
2241 set_value_range_to_varying (&vr0);
2243 if (TREE_CODE (op1) == SSA_NAME)
2244 vr1 = *(get_value_range (op1));
2245 else if (is_gimple_min_invariant (op1))
2246 set_value_range_to_value (&vr1, op1, NULL);
2248 set_value_range_to_varying (&vr1);
2250 /* If both ranges are UNDEFINED, so is the result. */
2251 if (vr0.type == VR_UNDEFINED && vr1.type == VR_UNDEFINED)
2253 set_value_range_to_undefined (vr);
2256 /* If one of the ranges is UNDEFINED drop it to VARYING for the following
2257 code. At some point we may want to special-case operations that
2258 have UNDEFINED result for all or some value-ranges of the not UNDEFINED
2260 else if (vr0.type == VR_UNDEFINED)
2261 set_value_range_to_varying (&vr0);
2262 else if (vr1.type == VR_UNDEFINED)
2263 set_value_range_to_varying (&vr1);
2265 /* The type of the resulting value range defaults to VR0.TYPE. */
2268 /* Refuse to operate on VARYING ranges, ranges of different kinds
2269 and symbolic ranges. As an exception, we allow BIT_AND_EXPR
2270 because we may be able to derive a useful range even if one of
2271 the operands is VR_VARYING or symbolic range. Similarly for
2272 divisions. TODO, we may be able to derive anti-ranges in
2274 if (code != BIT_AND_EXPR
2275 && code != BIT_IOR_EXPR
2276 && code != TRUNC_DIV_EXPR
2277 && code != FLOOR_DIV_EXPR
2278 && code != CEIL_DIV_EXPR
2279 && code != EXACT_DIV_EXPR
2280 && code != ROUND_DIV_EXPR
2281 && code != TRUNC_MOD_EXPR
2282 && (vr0.type == VR_VARYING
2283 || vr1.type == VR_VARYING
2284 || vr0.type != vr1.type
2285 || symbolic_range_p (&vr0)
2286 || symbolic_range_p (&vr1)))
2288 set_value_range_to_varying (vr);
2292 /* Now evaluate the expression to determine the new range. */
2293 if (POINTER_TYPE_P (expr_type)
2294 || POINTER_TYPE_P (TREE_TYPE (op0))
2295 || POINTER_TYPE_P (TREE_TYPE (op1)))
2297 if (code == BIT_IOR_EXPR)
2299 set_value_range_to_varying (vr);
2302 else if (code == MIN_EXPR || code == MAX_EXPR)
2304 /* For MIN/MAX expressions with pointers, we only care about
2305 nullness, if both are non null, then the result is nonnull.
2306 If both are null, then the result is null. Otherwise they
2308 if (range_is_nonnull (&vr0) && range_is_nonnull (&vr1))
2309 set_value_range_to_nonnull (vr, expr_type);
2310 else if (range_is_null (&vr0) && range_is_null (&vr1))
2311 set_value_range_to_null (vr, expr_type);
2313 set_value_range_to_varying (vr);
2317 if (code == POINTER_PLUS_EXPR)
2319 /* For pointer types, we are really only interested in asserting
2320 whether the expression evaluates to non-NULL. */
2321 if (range_is_nonnull (&vr0) || range_is_nonnull (&vr1))
2322 set_value_range_to_nonnull (vr, expr_type);
2323 else if (range_is_null (&vr0) && range_is_null (&vr1))
2324 set_value_range_to_null (vr, expr_type);
2326 set_value_range_to_varying (vr);
2328 else if (code == BIT_AND_EXPR)
2330 /* For pointer types, we are really only interested in asserting
2331 whether the expression evaluates to non-NULL. */
2332 if (range_is_nonnull (&vr0) && range_is_nonnull (&vr1))
2333 set_value_range_to_nonnull (vr, expr_type);
2334 else if (range_is_null (&vr0) || range_is_null (&vr1))
2335 set_value_range_to_null (vr, expr_type);
2337 set_value_range_to_varying (vr);
2345 /* For integer ranges, apply the operation to each end of the
2346 range and see what we end up with. */
2347 if (code == PLUS_EXPR
2349 || code == MAX_EXPR)
2351 /* If we have a PLUS_EXPR with two VR_ANTI_RANGEs, drop to
2352 VR_VARYING. It would take more effort to compute a precise
2353 range for such a case. For example, if we have op0 == 1 and
2354 op1 == -1 with their ranges both being ~[0,0], we would have
2355 op0 + op1 == 0, so we cannot claim that the sum is in ~[0,0].
2356 Note that we are guaranteed to have vr0.type == vr1.type at
2358 if (vr0.type == VR_ANTI_RANGE)
2360 if (code == PLUS_EXPR)
2362 set_value_range_to_varying (vr);
2365 /* For MIN_EXPR and MAX_EXPR with two VR_ANTI_RANGEs,
2366 the resulting VR_ANTI_RANGE is the same - intersection
2367 of the two ranges. */
2368 min = vrp_int_const_binop (MAX_EXPR, vr0.min, vr1.min);
2369 max = vrp_int_const_binop (MIN_EXPR, vr0.max, vr1.max);
2373 /* For operations that make the resulting range directly
2374 proportional to the original ranges, apply the operation to
2375 the same end of each range. */
2376 min = vrp_int_const_binop (code, vr0.min, vr1.min);
2377 max = vrp_int_const_binop (code, vr0.max, vr1.max);
2380 /* If both additions overflowed the range kind is still correct.
2381 This happens regularly with subtracting something in unsigned
2383 ??? See PR30318 for all the cases we do not handle. */
2384 if (code == PLUS_EXPR
2385 && (TREE_OVERFLOW (min) && !is_overflow_infinity (min))
2386 && (TREE_OVERFLOW (max) && !is_overflow_infinity (max)))
2388 min = build_int_cst_wide (TREE_TYPE (min),
2389 TREE_INT_CST_LOW (min),
2390 TREE_INT_CST_HIGH (min));
2391 max = build_int_cst_wide (TREE_TYPE (max),
2392 TREE_INT_CST_LOW (max),
2393 TREE_INT_CST_HIGH (max));
2396 else if (code == MULT_EXPR
2397 || code == TRUNC_DIV_EXPR
2398 || code == FLOOR_DIV_EXPR
2399 || code == CEIL_DIV_EXPR
2400 || code == EXACT_DIV_EXPR
2401 || code == ROUND_DIV_EXPR
2402 || code == RSHIFT_EXPR)
2408 /* If we have an unsigned MULT_EXPR with two VR_ANTI_RANGEs,
2409 drop to VR_VARYING. It would take more effort to compute a
2410 precise range for such a case. For example, if we have
2411 op0 == 65536 and op1 == 65536 with their ranges both being
2412 ~[0,0] on a 32-bit machine, we would have op0 * op1 == 0, so
2413 we cannot claim that the product is in ~[0,0]. Note that we
2414 are guaranteed to have vr0.type == vr1.type at this
2416 if (code == MULT_EXPR
2417 && vr0.type == VR_ANTI_RANGE
2418 && !TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (op0)))
2420 set_value_range_to_varying (vr);
2424 /* If we have a RSHIFT_EXPR with any shift values outside [0..prec-1],
2425 then drop to VR_VARYING. Outside of this range we get undefined
2426 behavior from the shift operation. We cannot even trust
2427 SHIFT_COUNT_TRUNCATED at this stage, because that applies to rtl
2428 shifts, and the operation at the tree level may be widened. */
2429 if (code == RSHIFT_EXPR)
2431 if (vr1.type == VR_ANTI_RANGE
2432 || !vrp_expr_computes_nonnegative (op1, &sop)
2434 (build_int_cst (TREE_TYPE (vr1.max),
2435 TYPE_PRECISION (expr_type) - 1),
2438 set_value_range_to_varying (vr);
2443 else if ((code == TRUNC_DIV_EXPR
2444 || code == FLOOR_DIV_EXPR
2445 || code == CEIL_DIV_EXPR
2446 || code == EXACT_DIV_EXPR
2447 || code == ROUND_DIV_EXPR)
2448 && (vr0.type != VR_RANGE || symbolic_range_p (&vr0)))
2450 /* For division, if op1 has VR_RANGE but op0 does not, something
2451 can be deduced just from that range. Say [min, max] / [4, max]
2452 gives [min / 4, max / 4] range. */
2453 if (vr1.type == VR_RANGE
2454 && !symbolic_range_p (&vr1)
2455 && !range_includes_zero_p (&vr1))
2457 vr0.type = type = VR_RANGE;
2458 vr0.min = vrp_val_min (TREE_TYPE (op0));
2459 vr0.max = vrp_val_max (TREE_TYPE (op1));
2463 set_value_range_to_varying (vr);
2468 /* For divisions, if flag_non_call_exceptions is true, we must
2469 not eliminate a division by zero. */
2470 if ((code == TRUNC_DIV_EXPR
2471 || code == FLOOR_DIV_EXPR
2472 || code == CEIL_DIV_EXPR
2473 || code == EXACT_DIV_EXPR
2474 || code == ROUND_DIV_EXPR)
2475 && cfun->can_throw_non_call_exceptions
2476 && (vr1.type != VR_RANGE
2477 || symbolic_range_p (&vr1)
2478 || range_includes_zero_p (&vr1)))
2480 set_value_range_to_varying (vr);
2484 /* For divisions, if op0 is VR_RANGE, we can deduce a range
2485 even if op1 is VR_VARYING, VR_ANTI_RANGE, symbolic or can
2487 if ((code == TRUNC_DIV_EXPR
2488 || code == FLOOR_DIV_EXPR
2489 || code == CEIL_DIV_EXPR
2490 || code == EXACT_DIV_EXPR
2491 || code == ROUND_DIV_EXPR)
2492 && vr0.type == VR_RANGE
2493 && (vr1.type != VR_RANGE
2494 || symbolic_range_p (&vr1)
2495 || range_includes_zero_p (&vr1)))
2497 tree zero = build_int_cst (TREE_TYPE (vr0.min), 0);
2503 if (vrp_expr_computes_nonnegative (op1, &sop) && !sop)
2505 /* For unsigned division or when divisor is known
2506 to be non-negative, the range has to cover
2507 all numbers from 0 to max for positive max
2508 and all numbers from min to 0 for negative min. */
2509 cmp = compare_values (vr0.max, zero);
2512 else if (cmp == 0 || cmp == 1)
2516 cmp = compare_values (vr0.min, zero);
2519 else if (cmp == 0 || cmp == -1)
2526 /* Otherwise the range is -max .. max or min .. -min
2527 depending on which bound is bigger in absolute value,
2528 as the division can change the sign. */
2529 abs_extent_range (vr, vr0.min, vr0.max);
2532 if (type == VR_VARYING)
2534 set_value_range_to_varying (vr);
2539 /* Multiplications and divisions are a bit tricky to handle,
2540 depending on the mix of signs we have in the two ranges, we
2541 need to operate on different values to get the minimum and
2542 maximum values for the new range. One approach is to figure
2543 out all the variations of range combinations and do the
2546 However, this involves several calls to compare_values and it
2547 is pretty convoluted. It's simpler to do the 4 operations
2548 (MIN0 OP MIN1, MIN0 OP MAX1, MAX0 OP MIN1 and MAX0 OP MAX0 OP
2549 MAX1) and then figure the smallest and largest values to form
2553 gcc_assert ((vr0.type == VR_RANGE
2554 || (code == MULT_EXPR && vr0.type == VR_ANTI_RANGE))
2555 && vr0.type == vr1.type);
2557 /* Compute the 4 cross operations. */
2559 val[0] = vrp_int_const_binop (code, vr0.min, vr1.min);
2560 if (val[0] == NULL_TREE)
2563 if (vr1.max == vr1.min)
2567 val[1] = vrp_int_const_binop (code, vr0.min, vr1.max);
2568 if (val[1] == NULL_TREE)
2572 if (vr0.max == vr0.min)
2576 val[2] = vrp_int_const_binop (code, vr0.max, vr1.min);
2577 if (val[2] == NULL_TREE)
2581 if (vr0.min == vr0.max || vr1.min == vr1.max)
2585 val[3] = vrp_int_const_binop (code, vr0.max, vr1.max);
2586 if (val[3] == NULL_TREE)
2592 set_value_range_to_varying (vr);
2596 /* Set MIN to the minimum of VAL[i] and MAX to the maximum
2600 for (i = 1; i < 4; i++)
2602 if (!is_gimple_min_invariant (min)
2603 || (TREE_OVERFLOW (min) && !is_overflow_infinity (min))
2604 || !is_gimple_min_invariant (max)
2605 || (TREE_OVERFLOW (max) && !is_overflow_infinity (max)))
2610 if (!is_gimple_min_invariant (val[i])
2611 || (TREE_OVERFLOW (val[i])
2612 && !is_overflow_infinity (val[i])))
2614 /* If we found an overflowed value, set MIN and MAX
2615 to it so that we set the resulting range to
2621 if (compare_values (val[i], min) == -1)
2624 if (compare_values (val[i], max) == 1)
2630 else if (code == TRUNC_MOD_EXPR)
2633 if (vr1.type != VR_RANGE
2634 || symbolic_range_p (&vr1)
2635 || range_includes_zero_p (&vr1)
2636 || vrp_val_is_min (vr1.min))
2638 set_value_range_to_varying (vr);
2642 /* Compute MAX <|vr1.min|, |vr1.max|> - 1. */
2643 max = fold_unary_to_constant (ABS_EXPR, TREE_TYPE (vr1.min), vr1.min);
2644 if (tree_int_cst_lt (max, vr1.max))
2646 max = int_const_binop (MINUS_EXPR, max, integer_one_node);
2647 /* If the dividend is non-negative the modulus will be
2648 non-negative as well. */
2649 if (TYPE_UNSIGNED (TREE_TYPE (max))
2650 || (vrp_expr_computes_nonnegative (op0, &sop) && !sop))
2651 min = build_int_cst (TREE_TYPE (max), 0);
2653 min = fold_unary_to_constant (NEGATE_EXPR, TREE_TYPE (max), max);
2655 else if (code == MINUS_EXPR)
2657 /* If we have a MINUS_EXPR with two VR_ANTI_RANGEs, drop to
2658 VR_VARYING. It would take more effort to compute a precise
2659 range for such a case. For example, if we have op0 == 1 and
2660 op1 == 1 with their ranges both being ~[0,0], we would have
2661 op0 - op1 == 0, so we cannot claim that the difference is in
2662 ~[0,0]. Note that we are guaranteed to have
2663 vr0.type == vr1.type at this point. */
2664 if (vr0.type == VR_ANTI_RANGE)
2666 set_value_range_to_varying (vr);
2670 /* For MINUS_EXPR, apply the operation to the opposite ends of
2672 min = vrp_int_const_binop (code, vr0.min, vr1.max);
2673 max = vrp_int_const_binop (code, vr0.max, vr1.min);
2675 else if (code == BIT_AND_EXPR || code == BIT_IOR_EXPR)
2677 bool vr0_int_cst_singleton_p, vr1_int_cst_singleton_p;
2678 bool int_cst_range0, int_cst_range1;
2679 double_int may_be_nonzero0, may_be_nonzero1;
2680 double_int must_be_nonzero0, must_be_nonzero1;
2681 value_range_t *non_singleton_vr;
2684 vr0_int_cst_singleton_p = range_int_cst_singleton_p (&vr0);
2685 vr1_int_cst_singleton_p = range_int_cst_singleton_p (&vr1);
2686 int_cst_range0 = zero_nonzero_bits_from_vr (&vr0, &may_be_nonzero0,
2688 int_cst_range1 = zero_nonzero_bits_from_vr (&vr1, &may_be_nonzero1,
2691 singleton_val = (vr0_int_cst_singleton_p ? vr0.min : vr1.min);
2692 non_singleton_vr = (vr0_int_cst_singleton_p ? &vr1 : &vr0);
2695 if (vr0_int_cst_singleton_p && vr1_int_cst_singleton_p)
2696 min = max = int_const_binop (code, vr0.max, vr1.max);
2697 else if ((vr0_int_cst_singleton_p || vr1_int_cst_singleton_p)
2698 && (integer_zerop (singleton_val)
2699 || integer_all_onesp (singleton_val)))
2701 /* If one of the operands is zero for and-case, we know that
2702 * the whole expression evaluates zero.
2703 If one of the operands has all bits set to one for
2704 or-case, we know that the whole expression evaluates
2706 min = max = singleton_val;
2707 if ((code == BIT_IOR_EXPR
2708 && integer_zerop (singleton_val))
2709 || (code == BIT_AND_EXPR
2710 && integer_all_onesp (singleton_val)))
2711 /* If one of the operands has all bits set to one, we know
2712 that the whole expression evaluates to the other one for
2714 If one of the operands is zero, we know that the whole
2715 expression evaluates to the other one for the or-case. */
2717 type = non_singleton_vr->type;
2718 min = non_singleton_vr->min;
2719 max = non_singleton_vr->max;
2721 set_value_range (vr, type, min, max, NULL);
2724 else if (!int_cst_range0 && !int_cst_range1)
2726 set_value_range_to_varying (vr);
2729 else if (code == BIT_AND_EXPR)
2731 min = double_int_to_tree (expr_type,
2732 double_int_and (must_be_nonzero0,
2734 max = double_int_to_tree (expr_type,
2735 double_int_and (may_be_nonzero0,
2737 if (TREE_OVERFLOW (min) || tree_int_cst_sgn (min) < 0)
2739 if (TREE_OVERFLOW (max) || tree_int_cst_sgn (max) < 0)
2741 if (int_cst_range0 && tree_int_cst_sgn (vr0.min) >= 0)
2743 if (min == NULL_TREE)
2744 min = build_int_cst (expr_type, 0);
2745 if (max == NULL_TREE || tree_int_cst_lt (vr0.max, max))
2748 if (int_cst_range1 && tree_int_cst_sgn (vr1.min) >= 0)
2750 if (min == NULL_TREE)
2751 min = build_int_cst (expr_type, 0);
2752 if (max == NULL_TREE || tree_int_cst_lt (vr1.max, max))
2756 else if (!int_cst_range0
2758 || tree_int_cst_sgn (vr0.min) < 0
2759 || tree_int_cst_sgn (vr1.min) < 0)
2761 set_value_range_to_varying (vr);
2766 min = double_int_to_tree (expr_type,
2767 double_int_ior (must_be_nonzero0,
2769 max = double_int_to_tree (expr_type,
2770 double_int_ior (may_be_nonzero0,
2772 if (TREE_OVERFLOW (min) || tree_int_cst_sgn (min) < 0)
2775 min = vrp_int_const_binop (MAX_EXPR, min, vr0.min);
2776 if (TREE_OVERFLOW (max) || tree_int_cst_sgn (max) < 0)
2778 min = vrp_int_const_binop (MAX_EXPR, min, vr1.min);
2784 /* If either MIN or MAX overflowed, then set the resulting range to
2785 VARYING. But we do accept an overflow infinity
2787 if (min == NULL_TREE
2788 || !is_gimple_min_invariant (min)
2789 || (TREE_OVERFLOW (min) && !is_overflow_infinity (min))
2791 || !is_gimple_min_invariant (max)
2792 || (TREE_OVERFLOW (max) && !is_overflow_infinity (max)))
2794 set_value_range_to_varying (vr);
2800 2) [-INF, +-INF(OVF)]
2801 3) [+-INF(OVF), +INF]
2802 4) [+-INF(OVF), +-INF(OVF)]
2803 We learn nothing when we have INF and INF(OVF) on both sides.
2804 Note that we do accept [-INF, -INF] and [+INF, +INF] without
2806 if ((vrp_val_is_min (min) || is_overflow_infinity (min))
2807 && (vrp_val_is_max (max) || is_overflow_infinity (max)))
2809 set_value_range_to_varying (vr);
2813 cmp = compare_values (min, max);
2814 if (cmp == -2 || cmp == 1)
2816 /* If the new range has its limits swapped around (MIN > MAX),
2817 then the operation caused one of them to wrap around, mark
2818 the new range VARYING. */
2819 set_value_range_to_varying (vr);
2822 set_value_range (vr, type, min, max, NULL);
2826 /* Extract range information from a unary expression EXPR based on
2827 the range of its operand and the expression code. */
2830 extract_range_from_unary_expr (value_range_t *vr, enum tree_code code,
2831 tree type, tree op0)
2835 value_range_t vr0 = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
2837 /* Refuse to operate on certain unary expressions for which we
2838 cannot easily determine a resulting range. */
2839 if (code == FIX_TRUNC_EXPR
2840 || code == FLOAT_EXPR
2841 || code == BIT_NOT_EXPR
2842 || code == CONJ_EXPR)
2844 /* We can still do constant propagation here. */
2845 if ((op0 = op_with_constant_singleton_value_range (op0)) != NULL_TREE)
2847 tree tem = fold_unary (code, type, op0);
2849 && is_gimple_min_invariant (tem)
2850 && !is_overflow_infinity (tem))
2852 set_value_range (vr, VR_RANGE, tem, tem, NULL);
2856 set_value_range_to_varying (vr);
2860 /* Get value ranges for the operand. For constant operands, create
2861 a new value range with the operand to simplify processing. */
2862 if (TREE_CODE (op0) == SSA_NAME)
2863 vr0 = *(get_value_range (op0));
2864 else if (is_gimple_min_invariant (op0))
2865 set_value_range_to_value (&vr0, op0, NULL);
2867 set_value_range_to_varying (&vr0);
2869 /* If VR0 is UNDEFINED, so is the result. */
2870 if (vr0.type == VR_UNDEFINED)
2872 set_value_range_to_undefined (vr);
2876 /* Refuse to operate on symbolic ranges, or if neither operand is
2877 a pointer or integral type. */
2878 if ((!INTEGRAL_TYPE_P (TREE_TYPE (op0))
2879 && !POINTER_TYPE_P (TREE_TYPE (op0)))
2880 || (vr0.type != VR_VARYING
2881 && symbolic_range_p (&vr0)))
2883 set_value_range_to_varying (vr);
2887 /* If the expression involves pointers, we are only interested in
2888 determining if it evaluates to NULL [0, 0] or non-NULL (~[0, 0]). */
2889 if (POINTER_TYPE_P (type) || POINTER_TYPE_P (TREE_TYPE (op0)))
2894 if (range_is_nonnull (&vr0)
2895 || (tree_unary_nonzero_warnv_p (code, type, op0, &sop)
2897 set_value_range_to_nonnull (vr, type);
2898 else if (range_is_null (&vr0))
2899 set_value_range_to_null (vr, type);
2901 set_value_range_to_varying (vr);
2906 /* Handle unary expressions on integer ranges. */
2907 if (CONVERT_EXPR_CODE_P (code)
2908 && INTEGRAL_TYPE_P (type)
2909 && INTEGRAL_TYPE_P (TREE_TYPE (op0)))
2911 tree inner_type = TREE_TYPE (op0);
2912 tree outer_type = type;
2914 /* If VR0 is varying and we increase the type precision, assume
2915 a full range for the following transformation. */
2916 if (vr0.type == VR_VARYING
2917 && TYPE_PRECISION (inner_type) < TYPE_PRECISION (outer_type))
2919 vr0.type = VR_RANGE;
2920 vr0.min = TYPE_MIN_VALUE (inner_type);
2921 vr0.max = TYPE_MAX_VALUE (inner_type);
2924 /* If VR0 is a constant range or anti-range and the conversion is
2925 not truncating we can convert the min and max values and
2926 canonicalize the resulting range. Otherwise we can do the
2927 conversion if the size of the range is less than what the
2928 precision of the target type can represent and the range is
2929 not an anti-range. */
2930 if ((vr0.type == VR_RANGE
2931 || vr0.type == VR_ANTI_RANGE)
2932 && TREE_CODE (vr0.min) == INTEGER_CST
2933 && TREE_CODE (vr0.max) == INTEGER_CST
2934 && (!is_overflow_infinity (vr0.min)
2935 || (vr0.type == VR_RANGE
2936 && TYPE_PRECISION (outer_type) > TYPE_PRECISION (inner_type)
2937 && needs_overflow_infinity (outer_type)
2938 && supports_overflow_infinity (outer_type)))
2939 && (!is_overflow_infinity (vr0.max)
2940 || (vr0.type == VR_RANGE
2941 && TYPE_PRECISION (outer_type) > TYPE_PRECISION (inner_type)
2942 && needs_overflow_infinity (outer_type)
2943 && supports_overflow_infinity (outer_type)))
2944 && (TYPE_PRECISION (outer_type) >= TYPE_PRECISION (inner_type)
2945 || (vr0.type == VR_RANGE
2946 && integer_zerop (int_const_binop (RSHIFT_EXPR,
2947 int_const_binop (MINUS_EXPR, vr0.max, vr0.min),
2948 size_int (TYPE_PRECISION (outer_type)))))))
2950 tree new_min, new_max;
2951 new_min = force_fit_type_double (outer_type,
2952 tree_to_double_int (vr0.min),
2954 new_max = force_fit_type_double (outer_type,
2955 tree_to_double_int (vr0.max),
2957 if (is_overflow_infinity (vr0.min))
2958 new_min = negative_overflow_infinity (outer_type);
2959 if (is_overflow_infinity (vr0.max))
2960 new_max = positive_overflow_infinity (outer_type);
2961 set_and_canonicalize_value_range (vr, vr0.type,
2962 new_min, new_max, NULL);
2966 set_value_range_to_varying (vr);
2970 /* Conversion of a VR_VARYING value to a wider type can result
2971 in a usable range. So wait until after we've handled conversions
2972 before dropping the result to VR_VARYING if we had a source
2973 operand that is VR_VARYING. */
2974 if (vr0.type == VR_VARYING)
2976 set_value_range_to_varying (vr);
2980 /* Apply the operation to each end of the range and see what we end
2982 if (code == NEGATE_EXPR
2983 && !TYPE_UNSIGNED (type))
2985 /* NEGATE_EXPR flips the range around. We need to treat
2986 TYPE_MIN_VALUE specially. */
2987 if (is_positive_overflow_infinity (vr0.max))
2988 min = negative_overflow_infinity (type);
2989 else if (is_negative_overflow_infinity (vr0.max))
2990 min = positive_overflow_infinity (type);
2991 else if (!vrp_val_is_min (vr0.max))
2992 min = fold_unary_to_constant (code, type, vr0.max);
2993 else if (needs_overflow_infinity (type))
2995 if (supports_overflow_infinity (type)
2996 && !is_overflow_infinity (vr0.min)
2997 && !vrp_val_is_min (vr0.min))
2998 min = positive_overflow_infinity (type);
3001 set_value_range_to_varying (vr);
3006 min = TYPE_MIN_VALUE (type);
3008 if (is_positive_overflow_infinity (vr0.min))
3009 max = negative_overflow_infinity (type);
3010 else if (is_negative_overflow_infinity (vr0.min))
3011 max = positive_overflow_infinity (type);
3012 else if (!vrp_val_is_min (vr0.min))
3013 max = fold_unary_to_constant (code, type, vr0.min);
3014 else if (needs_overflow_infinity (type))
3016 if (supports_overflow_infinity (type))
3017 max = positive_overflow_infinity (type);
3020 set_value_range_to_varying (vr);
3025 max = TYPE_MIN_VALUE (type);
3027 else if (code == NEGATE_EXPR
3028 && TYPE_UNSIGNED (type))
3030 if (!range_includes_zero_p (&vr0))
3032 max = fold_unary_to_constant (code, type, vr0.min);
3033 min = fold_unary_to_constant (code, type, vr0.max);
3037 if (range_is_null (&vr0))
3038 set_value_range_to_null (vr, type);
3040 set_value_range_to_varying (vr);
3044 else if (code == ABS_EXPR
3045 && !TYPE_UNSIGNED (type))
3047 /* -TYPE_MIN_VALUE = TYPE_MIN_VALUE with flag_wrapv so we can't get a
3049 if (!TYPE_OVERFLOW_UNDEFINED (type)
3050 && ((vr0.type == VR_RANGE
3051 && vrp_val_is_min (vr0.min))
3052 || (vr0.type == VR_ANTI_RANGE
3053 && !vrp_val_is_min (vr0.min)
3054 && !range_includes_zero_p (&vr0))))
3056 set_value_range_to_varying (vr);
3060 /* ABS_EXPR may flip the range around, if the original range
3061 included negative values. */
3062 if (is_overflow_infinity (vr0.min))
3063 min = positive_overflow_infinity (type);
3064 else if (!vrp_val_is_min (vr0.min))
3065 min = fold_unary_to_constant (code, type, vr0.min);
3066 else if (!needs_overflow_infinity (type))
3067 min = TYPE_MAX_VALUE (type);
3068 else if (supports_overflow_infinity (type))
3069 min = positive_overflow_infinity (type);
3072 set_value_range_to_varying (vr);
3076 if (is_overflow_infinity (vr0.max))
3077 max = positive_overflow_infinity (type);
3078 else if (!vrp_val_is_min (vr0.max))
3079 max = fold_unary_to_constant (code, type, vr0.max);
3080 else if (!needs_overflow_infinity (type))
3081 max = TYPE_MAX_VALUE (type);
3082 else if (supports_overflow_infinity (type)
3083 /* We shouldn't generate [+INF, +INF] as set_value_range
3084 doesn't like this and ICEs. */
3085 && !is_positive_overflow_infinity (min))
3086 max = positive_overflow_infinity (type);
3089 set_value_range_to_varying (vr);
3093 cmp = compare_values (min, max);
3095 /* If a VR_ANTI_RANGEs contains zero, then we have
3096 ~[-INF, min(MIN, MAX)]. */
3097 if (vr0.type == VR_ANTI_RANGE)
3099 if (range_includes_zero_p (&vr0))
3101 /* Take the lower of the two values. */
3105 /* Create ~[-INF, min (abs(MIN), abs(MAX))]
3106 or ~[-INF + 1, min (abs(MIN), abs(MAX))] when
3107 flag_wrapv is set and the original anti-range doesn't include
3108 TYPE_MIN_VALUE, remember -TYPE_MIN_VALUE = TYPE_MIN_VALUE. */
3109 if (TYPE_OVERFLOW_WRAPS (type))
3111 tree type_min_value = TYPE_MIN_VALUE (type);
3113 min = (vr0.min != type_min_value
3114 ? int_const_binop (PLUS_EXPR, type_min_value,
3120 if (overflow_infinity_range_p (&vr0))
3121 min = negative_overflow_infinity (type);
3123 min = TYPE_MIN_VALUE (type);
3128 /* All else has failed, so create the range [0, INF], even for
3129 flag_wrapv since TYPE_MIN_VALUE is in the original
3131 vr0.type = VR_RANGE;
3132 min = build_int_cst (type, 0);
3133 if (needs_overflow_infinity (type))
3135 if (supports_overflow_infinity (type))
3136 max = positive_overflow_infinity (type);
3139 set_value_range_to_varying (vr);
3144 max = TYPE_MAX_VALUE (type);
3148 /* If the range contains zero then we know that the minimum value in the
3149 range will be zero. */
3150 else if (range_includes_zero_p (&vr0))
3154 min = build_int_cst (type, 0);
3158 /* If the range was reversed, swap MIN and MAX. */
3169 /* Otherwise, operate on each end of the range. */
3170 min = fold_unary_to_constant (code, type, vr0.min);
3171 max = fold_unary_to_constant (code, type, vr0.max);
3173 if (needs_overflow_infinity (type))
3175 gcc_assert (code != NEGATE_EXPR && code != ABS_EXPR);
3177 /* If both sides have overflowed, we don't know
3179 if ((is_overflow_infinity (vr0.min)
3180 || TREE_OVERFLOW (min))
3181 && (is_overflow_infinity (vr0.max)
3182 || TREE_OVERFLOW (max)))
3184 set_value_range_to_varying (vr);
3188 if (is_overflow_infinity (vr0.min))
3190 else if (TREE_OVERFLOW (min))
3192 if (supports_overflow_infinity (type))
3193 min = (tree_int_cst_sgn (min) >= 0
3194 ? positive_overflow_infinity (TREE_TYPE (min))
3195 : negative_overflow_infinity (TREE_TYPE (min)));
3198 set_value_range_to_varying (vr);
3203 if (is_overflow_infinity (vr0.max))
3205 else if (TREE_OVERFLOW (max))
3207 if (supports_overflow_infinity (type))
3208 max = (tree_int_cst_sgn (max) >= 0
3209 ? positive_overflow_infinity (TREE_TYPE (max))
3210 : negative_overflow_infinity (TREE_TYPE (max)));
3213 set_value_range_to_varying (vr);
3220 cmp = compare_values (min, max);
3221 if (cmp == -2 || cmp == 1)
3223 /* If the new range has its limits swapped around (MIN > MAX),
3224 then the operation caused one of them to wrap around, mark
3225 the new range VARYING. */
3226 set_value_range_to_varying (vr);
3229 set_value_range (vr, vr0.type, min, max, NULL);
3233 /* Extract range information from a conditional expression EXPR based on
3234 the ranges of each of its operands and the expression code. */
3237 extract_range_from_cond_expr (value_range_t *vr, tree expr)
3240 value_range_t vr0 = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
3241 value_range_t vr1 = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
3243 /* Get value ranges for each operand. For constant operands, create
3244 a new value range with the operand to simplify processing. */
3245 op0 = COND_EXPR_THEN (expr);
3246 if (TREE_CODE (op0) == SSA_NAME)
3247 vr0 = *(get_value_range (op0));
3248 else if (is_gimple_min_invariant (op0))
3249 set_value_range_to_value (&vr0, op0, NULL);
3251 set_value_range_to_varying (&vr0);
3253 op1 = COND_EXPR_ELSE (expr);
3254 if (TREE_CODE (op1) == SSA_NAME)
3255 vr1 = *(get_value_range (op1));
3256 else if (is_gimple_min_invariant (op1))
3257 set_value_range_to_value (&vr1, op1, NULL);
3259 set_value_range_to_varying (&vr1);
3261 /* The resulting value range is the union of the operand ranges */
3262 vrp_meet (&vr0, &vr1);
3263 copy_value_range (vr, &vr0);
3267 /* Extract range information from a comparison expression EXPR based
3268 on the range of its operand and the expression code. */
3271 extract_range_from_comparison (value_range_t *vr, enum tree_code code,
3272 tree type, tree op0, tree op1)
3277 val = vrp_evaluate_conditional_warnv_with_ops (code, op0, op1, false, &sop,
3280 /* A disadvantage of using a special infinity as an overflow
3281 representation is that we lose the ability to record overflow
3282 when we don't have an infinity. So we have to ignore a result
3283 which relies on overflow. */
3285 if (val && !is_overflow_infinity (val) && !sop)
3287 /* Since this expression was found on the RHS of an assignment,
3288 its type may be different from _Bool. Convert VAL to EXPR's
3290 val = fold_convert (type, val);
3291 if (is_gimple_min_invariant (val))
3292 set_value_range_to_value (vr, val, vr->equiv);
3294 set_value_range (vr, VR_RANGE, val, val, vr->equiv);
3297 /* The result of a comparison is always true or false. */
3298 set_value_range_to_truthvalue (vr, type);
3301 /* Try to derive a nonnegative or nonzero range out of STMT relying
3302 primarily on generic routines in fold in conjunction with range data.
3303 Store the result in *VR */
3306 extract_range_basic (value_range_t *vr, gimple stmt)
3309 tree type = gimple_expr_type (stmt);
3311 if (INTEGRAL_TYPE_P (type)
3312 && gimple_stmt_nonnegative_warnv_p (stmt, &sop))
3313 set_value_range_to_nonnegative (vr, type,
3314 sop || stmt_overflow_infinity (stmt));
3315 else if (vrp_stmt_computes_nonzero (stmt, &sop)
3317 set_value_range_to_nonnull (vr, type);
3319 set_value_range_to_varying (vr);
3323 /* Try to compute a useful range out of assignment STMT and store it
3327 extract_range_from_assignment (value_range_t *vr, gimple stmt)
3329 enum tree_code code = gimple_assign_rhs_code (stmt);
3331 if (code == ASSERT_EXPR)
3332 extract_range_from_assert (vr, gimple_assign_rhs1 (stmt));
3333 else if (code == SSA_NAME)
3334 extract_range_from_ssa_name (vr, gimple_assign_rhs1 (stmt));
3335 else if (TREE_CODE_CLASS (code) == tcc_binary)
3336 extract_range_from_binary_expr (vr, gimple_assign_rhs_code (stmt),
3337 gimple_expr_type (stmt),
3338 gimple_assign_rhs1 (stmt),
3339 gimple_assign_rhs2 (stmt));
3340 else if (TREE_CODE_CLASS (code) == tcc_unary)
3341 extract_range_from_unary_expr (vr, gimple_assign_rhs_code (stmt),
3342 gimple_expr_type (stmt),
3343 gimple_assign_rhs1 (stmt));
3344 else if (code == COND_EXPR)
3345 extract_range_from_cond_expr (vr, gimple_assign_rhs1 (stmt));
3346 else if (TREE_CODE_CLASS (code) == tcc_comparison)
3347 extract_range_from_comparison (vr, gimple_assign_rhs_code (stmt),
3348 gimple_expr_type (stmt),
3349 gimple_assign_rhs1 (stmt),
3350 gimple_assign_rhs2 (stmt));
3351 else if (get_gimple_rhs_class (code) == GIMPLE_SINGLE_RHS
3352 && is_gimple_min_invariant (gimple_assign_rhs1 (stmt)))
3353 set_value_range_to_value (vr, gimple_assign_rhs1 (stmt), NULL);
3355 set_value_range_to_varying (vr);
3357 if (vr->type == VR_VARYING)
3358 extract_range_basic (vr, stmt);
3361 /* Given a range VR, a LOOP and a variable VAR, determine whether it
3362 would be profitable to adjust VR using scalar evolution information
3363 for VAR. If so, update VR with the new limits. */
3366 adjust_range_with_scev (value_range_t *vr, struct loop *loop,
3367 gimple stmt, tree var)
3369 tree init, step, chrec, tmin, tmax, min, max, type, tem;
3370 enum ev_direction dir;
3372 /* TODO. Don't adjust anti-ranges. An anti-range may provide
3373 better opportunities than a regular range, but I'm not sure. */
3374 if (vr->type == VR_ANTI_RANGE)
3377 chrec = instantiate_parameters (loop, analyze_scalar_evolution (loop, var));
3379 /* Like in PR19590, scev can return a constant function. */
3380 if (is_gimple_min_invariant (chrec))
3382 set_value_range_to_value (vr, chrec, vr->equiv);
3386 if (TREE_CODE (chrec) != POLYNOMIAL_CHREC)
3389 init = initial_condition_in_loop_num (chrec, loop->num);
3390 tem = op_with_constant_singleton_value_range (init);
3393 step = evolution_part_in_loop_num (chrec, loop->num);
3394 tem = op_with_constant_singleton_value_range (step);
3398 /* If STEP is symbolic, we can't know whether INIT will be the
3399 minimum or maximum value in the range. Also, unless INIT is
3400 a simple expression, compare_values and possibly other functions
3401 in tree-vrp won't be able to handle it. */
3402 if (step == NULL_TREE
3403 || !is_gimple_min_invariant (step)
3404 || !valid_value_p (init))
3407 dir = scev_direction (chrec);
3408 if (/* Do not adjust ranges if we do not know whether the iv increases
3409 or decreases, ... */
3410 dir == EV_DIR_UNKNOWN
3411 /* ... or if it may wrap. */
3412 || scev_probably_wraps_p (init, step, stmt, get_chrec_loop (chrec),
3416 /* We use TYPE_MIN_VALUE and TYPE_MAX_VALUE here instead of
3417 negative_overflow_infinity and positive_overflow_infinity,
3418 because we have concluded that the loop probably does not
3421 type = TREE_TYPE (var);
3422 if (POINTER_TYPE_P (type) || !TYPE_MIN_VALUE (type))
3423 tmin = lower_bound_in_type (type, type);
3425 tmin = TYPE_MIN_VALUE (type);
3426 if (POINTER_TYPE_P (type) || !TYPE_MAX_VALUE (type))
3427 tmax = upper_bound_in_type (type, type);
3429 tmax = TYPE_MAX_VALUE (type);
3431 /* Try to use estimated number of iterations for the loop to constrain the
3432 final value in the evolution. */
3433 if (TREE_CODE (step) == INTEGER_CST
3434 && is_gimple_val (init)
3435 && (TREE_CODE (init) != SSA_NAME
3436 || get_value_range (init)->type == VR_RANGE))
3440 if (estimated_loop_iterations (loop, true, &nit))
3442 value_range_t maxvr = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
3444 bool unsigned_p = TYPE_UNSIGNED (TREE_TYPE (step));
3447 dtmp = double_int_mul_with_sign (tree_to_double_int (step), nit,
3448 unsigned_p, &overflow);
3449 /* If the multiplication overflowed we can't do a meaningful
3450 adjustment. Likewise if the result doesn't fit in the type
3451 of the induction variable. For a signed type we have to
3452 check whether the result has the expected signedness which
3453 is that of the step as number of iterations is unsigned. */
3455 && double_int_fits_to_tree_p (TREE_TYPE (init), dtmp)
3457 || ((dtmp.high ^ TREE_INT_CST_HIGH (step)) >= 0)))
3459 tem = double_int_to_tree (TREE_TYPE (init), dtmp);
3460 extract_range_from_binary_expr (&maxvr, PLUS_EXPR,
3461 TREE_TYPE (init), init, tem);
3462 /* Likewise if the addition did. */
3463 if (maxvr.type == VR_RANGE)
3472 if (vr->type == VR_VARYING || vr->type == VR_UNDEFINED)
3477 /* For VARYING or UNDEFINED ranges, just about anything we get
3478 from scalar evolutions should be better. */
3480 if (dir == EV_DIR_DECREASES)
3485 /* If we would create an invalid range, then just assume we
3486 know absolutely nothing. This may be over-conservative,
3487 but it's clearly safe, and should happen only in unreachable
3488 parts of code, or for invalid programs. */
3489 if (compare_values (min, max) == 1)
3492 set_value_range (vr, VR_RANGE, min, max, vr->equiv);
3494 else if (vr->type == VR_RANGE)
3499 if (dir == EV_DIR_DECREASES)
3501 /* INIT is the maximum value. If INIT is lower than VR->MAX
3502 but no smaller than VR->MIN, set VR->MAX to INIT. */
3503 if (compare_values (init, max) == -1)
3506 /* According to the loop information, the variable does not
3507 overflow. If we think it does, probably because of an
3508 overflow due to arithmetic on a different INF value,
3510 if (is_negative_overflow_infinity (min)
3511 || compare_values (min, tmin) == -1)
3517 /* If INIT is bigger than VR->MIN, set VR->MIN to INIT. */
3518 if (compare_values (init, min) == 1)
3521 if (is_positive_overflow_infinity (max)
3522 || compare_values (tmax, max) == -1)
3526 /* If we just created an invalid range with the minimum
3527 greater than the maximum, we fail conservatively.
3528 This should happen only in unreachable
3529 parts of code, or for invalid programs. */
3530 if (compare_values (min, max) == 1)
3533 set_value_range (vr, VR_RANGE, min, max, vr->equiv);
3537 /* Return true if VAR may overflow at STMT. This checks any available
3538 loop information to see if we can determine that VAR does not
3542 vrp_var_may_overflow (tree var, gimple stmt)
3545 tree chrec, init, step;
3547 if (current_loops == NULL)
3550 l = loop_containing_stmt (stmt);
3555 chrec = instantiate_parameters (l, analyze_scalar_evolution (l, var));
3556 if (TREE_CODE (chrec) != POLYNOMIAL_CHREC)
3559 init = initial_condition_in_loop_num (chrec, l->num);
3560 step = evolution_part_in_loop_num (chrec, l->num);
3562 if (step == NULL_TREE
3563 || !is_gimple_min_invariant (step)
3564 || !valid_value_p (init))
3567 /* If we get here, we know something useful about VAR based on the
3568 loop information. If it wraps, it may overflow. */
3570 if (scev_probably_wraps_p (init, step, stmt, get_chrec_loop (chrec),
3574 if (dump_file && (dump_flags & TDF_DETAILS) != 0)
3576 print_generic_expr (dump_file, var, 0);
3577 fprintf (dump_file, ": loop information indicates does not overflow\n");
3584 /* Given two numeric value ranges VR0, VR1 and a comparison code COMP:
3586 - Return BOOLEAN_TRUE_NODE if VR0 COMP VR1 always returns true for
3587 all the values in the ranges.
3589 - Return BOOLEAN_FALSE_NODE if the comparison always returns false.
3591 - Return NULL_TREE if it is not always possible to determine the
3592 value of the comparison.
3594 Also set *STRICT_OVERFLOW_P to indicate whether a range with an
3595 overflow infinity was used in the test. */
3599 compare_ranges (enum tree_code comp, value_range_t *vr0, value_range_t *vr1,
3600 bool *strict_overflow_p)
3602 /* VARYING or UNDEFINED ranges cannot be compared. */
3603 if (vr0->type == VR_VARYING
3604 || vr0->type == VR_UNDEFINED
3605 || vr1->type == VR_VARYING
3606 || vr1->type == VR_UNDEFINED)
3609 /* Anti-ranges need to be handled separately. */
3610 if (vr0->type == VR_ANTI_RANGE || vr1->type == VR_ANTI_RANGE)
3612 /* If both are anti-ranges, then we cannot compute any
3614 if (vr0->type == VR_ANTI_RANGE && vr1->type == VR_ANTI_RANGE)
3617 /* These comparisons are never statically computable. */
3624 /* Equality can be computed only between a range and an
3625 anti-range. ~[VAL1, VAL2] == [VAL1, VAL2] is always false. */
3626 if (vr0->type == VR_RANGE)
3628 /* To simplify processing, make VR0 the anti-range. */
3629 value_range_t *tmp = vr0;
3634 gcc_assert (comp == NE_EXPR || comp == EQ_EXPR);
3636 if (compare_values_warnv (vr0->min, vr1->min, strict_overflow_p) == 0
3637 && compare_values_warnv (vr0->max, vr1->max, strict_overflow_p) == 0)
3638 return (comp == NE_EXPR) ? boolean_true_node : boolean_false_node;
3643 if (!usable_range_p (vr0, strict_overflow_p)
3644 || !usable_range_p (vr1, strict_overflow_p))
3647 /* Simplify processing. If COMP is GT_EXPR or GE_EXPR, switch the
3648 operands around and change the comparison code. */
3649 if (comp == GT_EXPR || comp == GE_EXPR)
3652 comp = (comp == GT_EXPR) ? LT_EXPR : LE_EXPR;
3658 if (comp == EQ_EXPR)
3660 /* Equality may only be computed if both ranges represent
3661 exactly one value. */
3662 if (compare_values_warnv (vr0->min, vr0->max, strict_overflow_p) == 0
3663 && compare_values_warnv (vr1->min, vr1->max, strict_overflow_p) == 0)
3665 int cmp_min = compare_values_warnv (vr0->min, vr1->min,
3667 int cmp_max = compare_values_warnv (vr0->max, vr1->max,
3669 if (cmp_min == 0 && cmp_max == 0)
3670 return boolean_true_node;
3671 else if (cmp_min != -2 && cmp_max != -2)
3672 return boolean_false_node;
3674 /* If [V0_MIN, V1_MAX] < [V1_MIN, V1_MAX] then V0 != V1. */
3675 else if (compare_values_warnv (vr0->min, vr1->max,
3676 strict_overflow_p) == 1
3677 || compare_values_warnv (vr1->min, vr0->max,
3678 strict_overflow_p) == 1)
3679 return boolean_false_node;
3683 else if (comp == NE_EXPR)
3687 /* If VR0 is completely to the left or completely to the right
3688 of VR1, they are always different. Notice that we need to
3689 make sure that both comparisons yield similar results to
3690 avoid comparing values that cannot be compared at
3692 cmp1 = compare_values_warnv (vr0->max, vr1->min, strict_overflow_p);
3693 cmp2 = compare_values_warnv (vr0->min, vr1->max, strict_overflow_p);
3694 if ((cmp1 == -1 && cmp2 == -1) || (cmp1 == 1 && cmp2 == 1))
3695 return boolean_true_node;
3697 /* If VR0 and VR1 represent a single value and are identical,
3699 else if (compare_values_warnv (vr0->min, vr0->max,
3700 strict_overflow_p) == 0
3701 && compare_values_warnv (vr1->min, vr1->max,
3702 strict_overflow_p) == 0
3703 && compare_values_warnv (vr0->min, vr1->min,
3704 strict_overflow_p) == 0
3705 && compare_values_warnv (vr0->max, vr1->max,
3706 strict_overflow_p) == 0)
3707 return boolean_false_node;
3709 /* Otherwise, they may or may not be different. */
3713 else if (comp == LT_EXPR || comp == LE_EXPR)
3717 /* If VR0 is to the left of VR1, return true. */
3718 tst = compare_values_warnv (vr0->max, vr1->min, strict_overflow_p);
3719 if ((comp == LT_EXPR && tst == -1)
3720 || (comp == LE_EXPR && (tst == -1 || tst == 0)))
3722 if (overflow_infinity_range_p (vr0)
3723 || overflow_infinity_range_p (vr1))
3724 *strict_overflow_p = true;
3725 return boolean_true_node;
3728 /* If VR0 is to the right of VR1, return false. */
3729 tst = compare_values_warnv (vr0->min, vr1->max, strict_overflow_p);
3730 if ((comp == LT_EXPR && (tst == 0 || tst == 1))
3731 || (comp == LE_EXPR && tst == 1))
3733 if (overflow_infinity_range_p (vr0)
3734 || overflow_infinity_range_p (vr1))
3735 *strict_overflow_p = true;
3736 return boolean_false_node;
3739 /* Otherwise, we don't know. */
3747 /* Given a value range VR, a value VAL and a comparison code COMP, return
3748 BOOLEAN_TRUE_NODE if VR COMP VAL always returns true for all the
3749 values in VR. Return BOOLEAN_FALSE_NODE if the comparison
3750 always returns false. Return NULL_TREE if it is not always
3751 possible to determine the value of the comparison. Also set
3752 *STRICT_OVERFLOW_P to indicate whether a range with an overflow
3753 infinity was used in the test. */
3756 compare_range_with_value (enum tree_code comp, value_range_t *vr, tree val,
3757 bool *strict_overflow_p)
3759 if (vr->type == VR_VARYING || vr->type == VR_UNDEFINED)
3762 /* Anti-ranges need to be handled separately. */
3763 if (vr->type == VR_ANTI_RANGE)
3765 /* For anti-ranges, the only predicates that we can compute at
3766 compile time are equality and inequality. */
3773 /* ~[VAL_1, VAL_2] OP VAL is known if VAL_1 <= VAL <= VAL_2. */
3774 if (value_inside_range (val, vr) == 1)
3775 return (comp == NE_EXPR) ? boolean_true_node : boolean_false_node;
3780 if (!usable_range_p (vr, strict_overflow_p))
3783 if (comp == EQ_EXPR)
3785 /* EQ_EXPR may only be computed if VR represents exactly
3787 if (compare_values_warnv (vr->min, vr->max, strict_overflow_p) == 0)
3789 int cmp = compare_values_warnv (vr->min, val, strict_overflow_p);
3791 return boolean_true_node;
3792 else if (cmp == -1 || cmp == 1 || cmp == 2)
3793 return boolean_false_node;
3795 else if (compare_values_warnv (val, vr->min, strict_overflow_p) == -1
3796 || compare_values_warnv (vr->max, val, strict_overflow_p) == -1)
3797 return boolean_false_node;
3801 else if (comp == NE_EXPR)
3803 /* If VAL is not inside VR, then they are always different. */
3804 if (compare_values_warnv (vr->max, val, strict_overflow_p) == -1
3805 || compare_values_warnv (vr->min, val, strict_overflow_p) == 1)
3806 return boolean_true_node;
3808 /* If VR represents exactly one value equal to VAL, then return
3810 if (compare_values_warnv (vr->min, vr->max, strict_overflow_p) == 0
3811 && compare_values_warnv (vr->min, val, strict_overflow_p) == 0)
3812 return boolean_false_node;
3814 /* Otherwise, they may or may not be different. */
3817 else if (comp == LT_EXPR || comp == LE_EXPR)
3821 /* If VR is to the left of VAL, return true. */
3822 tst = compare_values_warnv (vr->max, val, strict_overflow_p);
3823 if ((comp == LT_EXPR && tst == -1)
3824 || (comp == LE_EXPR && (tst == -1 || tst == 0)))
3826 if (overflow_infinity_range_p (vr))
3827 *strict_overflow_p = true;
3828 return boolean_true_node;
3831 /* If VR is to the right of VAL, return false. */
3832 tst = compare_values_warnv (vr->min, val, strict_overflow_p);
3833 if ((comp == LT_EXPR && (tst == 0 || tst == 1))
3834 || (comp == LE_EXPR && tst == 1))
3836 if (overflow_infinity_range_p (vr))
3837 *strict_overflow_p = true;
3838 return boolean_false_node;
3841 /* Otherwise, we don't know. */
3844 else if (comp == GT_EXPR || comp == GE_EXPR)
3848 /* If VR is to the right of VAL, return true. */
3849 tst = compare_values_warnv (vr->min, val, strict_overflow_p);
3850 if ((comp == GT_EXPR && tst == 1)
3851 || (comp == GE_EXPR && (tst == 0 || tst == 1)))
3853 if (overflow_infinity_range_p (vr))
3854 *strict_overflow_p = true;
3855 return boolean_true_node;
3858 /* If VR is to the left of VAL, return false. */
3859 tst = compare_values_warnv (vr->max, val, strict_overflow_p);
3860 if ((comp == GT_EXPR && (tst == -1 || tst == 0))
3861 || (comp == GE_EXPR && tst == -1))
3863 if (overflow_infinity_range_p (vr))
3864 *strict_overflow_p = true;
3865 return boolean_false_node;
3868 /* Otherwise, we don't know. */
3876 /* Debugging dumps. */
3878 void dump_value_range (FILE *, value_range_t *);
3879 void debug_value_range (value_range_t *);
3880 void dump_all_value_ranges (FILE *);
3881 void debug_all_value_ranges (void);
3882 void dump_vr_equiv (FILE *, bitmap);
3883 void debug_vr_equiv (bitmap);
3886 /* Dump value range VR to FILE. */
3889 dump_value_range (FILE *file, value_range_t *vr)
3892 fprintf (file, "[]");
3893 else if (vr->type == VR_UNDEFINED)
3894 fprintf (file, "UNDEFINED");
3895 else if (vr->type == VR_RANGE || vr->type == VR_ANTI_RANGE)
3897 tree type = TREE_TYPE (vr->min);
3899 fprintf (file, "%s[", (vr->type == VR_ANTI_RANGE) ? "~" : "");
3901 if (is_negative_overflow_infinity (vr->min))
3902 fprintf (file, "-INF(OVF)");
3903 else if (INTEGRAL_TYPE_P (type)
3904 && !TYPE_UNSIGNED (type)
3905 && vrp_val_is_min (vr->min))
3906 fprintf (file, "-INF");
3908 print_generic_expr (file, vr->min, 0);
3910 fprintf (file, ", ");
3912 if (is_positive_overflow_infinity (vr->max))
3913 fprintf (file, "+INF(OVF)");
3914 else if (INTEGRAL_TYPE_P (type)
3915 && vrp_val_is_max (vr->max))
3916 fprintf (file, "+INF");
3918 print_generic_expr (file, vr->max, 0);
3920 fprintf (file, "]");
3927 fprintf (file, " EQUIVALENCES: { ");
3929 EXECUTE_IF_SET_IN_BITMAP (vr->equiv, 0, i, bi)
3931 print_generic_expr (file, ssa_name (i), 0);
3932 fprintf (file, " ");
3936 fprintf (file, "} (%u elements)", c);
3939 else if (vr->type == VR_VARYING)
3940 fprintf (file, "VARYING");
3942 fprintf (file, "INVALID RANGE");
3946 /* Dump value range VR to stderr. */
3949 debug_value_range (value_range_t *vr)
3951 dump_value_range (stderr, vr);
3952 fprintf (stderr, "\n");
3956 /* Dump value ranges of all SSA_NAMEs to FILE. */
3959 dump_all_value_ranges (FILE *file)
3963 for (i = 0; i < num_vr_values; i++)
3967 print_generic_expr (file, ssa_name (i), 0);
3968 fprintf (file, ": ");
3969 dump_value_range (file, vr_value[i]);
3970 fprintf (file, "\n");
3974 fprintf (file, "\n");
3978 /* Dump all value ranges to stderr. */
3981 debug_all_value_ranges (void)
3983 dump_all_value_ranges (stderr);
3987 /* Given a COND_EXPR COND of the form 'V OP W', and an SSA name V,
3988 create a new SSA name N and return the assertion assignment
3989 'V = ASSERT_EXPR <V, V OP W>'. */
3992 build_assert_expr_for (tree cond, tree v)
3997 gcc_assert (TREE_CODE (v) == SSA_NAME);
3998 n = duplicate_ssa_name (v, NULL);
4000 if (COMPARISON_CLASS_P (cond))
4002 tree a = build2 (ASSERT_EXPR, TREE_TYPE (v), v, cond);
4003 assertion = gimple_build_assign (n, a);
4005 else if (TREE_CODE (cond) == SSA_NAME)
4007 /* Given V, build the assignment N = true. */
4008 gcc_assert (v == cond);
4009 assertion = gimple_build_assign (n, boolean_true_node);
4014 SSA_NAME_DEF_STMT (n) = assertion;
4016 /* The new ASSERT_EXPR, creates a new SSA name that replaces the
4017 operand of the ASSERT_EXPR. Register the new name and the old one
4018 in the replacement table so that we can fix the SSA web after
4019 adding all the ASSERT_EXPRs. */
4020 register_new_name_mapping (n, v);
4026 /* Return false if EXPR is a predicate expression involving floating
4030 fp_predicate (gimple stmt)
4032 GIMPLE_CHECK (stmt, GIMPLE_COND);
4034 return FLOAT_TYPE_P (TREE_TYPE (gimple_cond_lhs (stmt)));
4038 /* If the range of values taken by OP can be inferred after STMT executes,
4039 return the comparison code (COMP_CODE_P) and value (VAL_P) that
4040 describes the inferred range. Return true if a range could be
4044 infer_value_range (gimple stmt, tree op, enum tree_code *comp_code_p, tree *val_p)
4047 *comp_code_p = ERROR_MARK;
4049 /* Do not attempt to infer anything in names that flow through
4051 if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (op))
4054 /* Similarly, don't infer anything from statements that may throw
4056 if (stmt_could_throw_p (stmt))
4059 /* If STMT is the last statement of a basic block with no
4060 successors, there is no point inferring anything about any of its
4061 operands. We would not be able to find a proper insertion point
4062 for the assertion, anyway. */
4063 if (stmt_ends_bb_p (stmt) && EDGE_COUNT (gimple_bb (stmt)->succs) == 0)
4066 /* We can only assume that a pointer dereference will yield
4067 non-NULL if -fdelete-null-pointer-checks is enabled. */
4068 if (flag_delete_null_pointer_checks
4069 && POINTER_TYPE_P (TREE_TYPE (op))
4070 && gimple_code (stmt) != GIMPLE_ASM)
4072 unsigned num_uses, num_loads, num_stores;
4074 count_uses_and_derefs (op, stmt, &num_uses, &num_loads, &num_stores);
4075 if (num_loads + num_stores > 0)
4077 *val_p = build_int_cst (TREE_TYPE (op), 0);
4078 *comp_code_p = NE_EXPR;
4087 void dump_asserts_for (FILE *, tree);
4088 void debug_asserts_for (tree);
4089 void dump_all_asserts (FILE *);
4090 void debug_all_asserts (void);
4092 /* Dump all the registered assertions for NAME to FILE. */
4095 dump_asserts_for (FILE *file, tree name)
4099 fprintf (file, "Assertions to be inserted for ");
4100 print_generic_expr (file, name, 0);
4101 fprintf (file, "\n");
4103 loc = asserts_for[SSA_NAME_VERSION (name)];
4106 fprintf (file, "\t");
4107 print_gimple_stmt (file, gsi_stmt (loc->si), 0, 0);
4108 fprintf (file, "\n\tBB #%d", loc->bb->index);
4111 fprintf (file, "\n\tEDGE %d->%d", loc->e->src->index,
4112 loc->e->dest->index);
4113 dump_edge_info (file, loc->e, 0);
4115 fprintf (file, "\n\tPREDICATE: ");
4116 print_generic_expr (file, name, 0);
4117 fprintf (file, " %s ", tree_code_name[(int)loc->comp_code]);
4118 print_generic_expr (file, loc->val, 0);
4119 fprintf (file, "\n\n");
4123 fprintf (file, "\n");
4127 /* Dump all the registered assertions for NAME to stderr. */
4130 debug_asserts_for (tree name)
4132 dump_asserts_for (stderr, name);
4136 /* Dump all the registered assertions for all the names to FILE. */
4139 dump_all_asserts (FILE *file)
4144 fprintf (file, "\nASSERT_EXPRs to be inserted\n\n");
4145 EXECUTE_IF_SET_IN_BITMAP (need_assert_for, 0, i, bi)
4146 dump_asserts_for (file, ssa_name (i));
4147 fprintf (file, "\n");
4151 /* Dump all the registered assertions for all the names to stderr. */
4154 debug_all_asserts (void)
4156 dump_all_asserts (stderr);
4160 /* If NAME doesn't have an ASSERT_EXPR registered for asserting
4161 'EXPR COMP_CODE VAL' at a location that dominates block BB or
4162 E->DEST, then register this location as a possible insertion point
4163 for ASSERT_EXPR <NAME, EXPR COMP_CODE VAL>.
4165 BB, E and SI provide the exact insertion point for the new
4166 ASSERT_EXPR. If BB is NULL, then the ASSERT_EXPR is to be inserted
4167 on edge E. Otherwise, if E is NULL, the ASSERT_EXPR is inserted on
4168 BB. If SI points to a COND_EXPR or a SWITCH_EXPR statement, then E
4169 must not be NULL. */
4172 register_new_assert_for (tree name, tree expr,
4173 enum tree_code comp_code,
4177 gimple_stmt_iterator si)
4179 assert_locus_t n, loc, last_loc;
4180 basic_block dest_bb;
4182 gcc_checking_assert (bb == NULL || e == NULL);
4185 gcc_checking_assert (gimple_code (gsi_stmt (si)) != GIMPLE_COND
4186 && gimple_code (gsi_stmt (si)) != GIMPLE_SWITCH);
4188 /* Never build an assert comparing against an integer constant with
4189 TREE_OVERFLOW set. This confuses our undefined overflow warning
4191 if (TREE_CODE (val) == INTEGER_CST
4192 && TREE_OVERFLOW (val))
4193 val = build_int_cst_wide (TREE_TYPE (val),
4194 TREE_INT_CST_LOW (val), TREE_INT_CST_HIGH (val));
4196 /* The new assertion A will be inserted at BB or E. We need to
4197 determine if the new location is dominated by a previously
4198 registered location for A. If we are doing an edge insertion,
4199 assume that A will be inserted at E->DEST. Note that this is not
4202 If E is a critical edge, it will be split. But even if E is
4203 split, the new block will dominate the same set of blocks that
4206 The reverse, however, is not true, blocks dominated by E->DEST
4207 will not be dominated by the new block created to split E. So,
4208 if the insertion location is on a critical edge, we will not use
4209 the new location to move another assertion previously registered
4210 at a block dominated by E->DEST. */
4211 dest_bb = (bb) ? bb : e->dest;
4213 /* If NAME already has an ASSERT_EXPR registered for COMP_CODE and
4214 VAL at a block dominating DEST_BB, then we don't need to insert a new
4215 one. Similarly, if the same assertion already exists at a block
4216 dominated by DEST_BB and the new location is not on a critical
4217 edge, then update the existing location for the assertion (i.e.,
4218 move the assertion up in the dominance tree).
4220 Note, this is implemented as a simple linked list because there
4221 should not be more than a handful of assertions registered per
4222 name. If this becomes a performance problem, a table hashed by
4223 COMP_CODE and VAL could be implemented. */
4224 loc = asserts_for[SSA_NAME_VERSION (name)];
4228 if (loc->comp_code == comp_code
4230 || operand_equal_p (loc->val, val, 0))
4231 && (loc->expr == expr
4232 || operand_equal_p (loc->expr, expr, 0)))
4234 /* If the assertion NAME COMP_CODE VAL has already been
4235 registered at a basic block that dominates DEST_BB, then
4236 we don't need to insert the same assertion again. Note
4237 that we don't check strict dominance here to avoid
4238 replicating the same assertion inside the same basic
4239 block more than once (e.g., when a pointer is
4240 dereferenced several times inside a block).
4242 An exception to this rule are edge insertions. If the
4243 new assertion is to be inserted on edge E, then it will
4244 dominate all the other insertions that we may want to
4245 insert in DEST_BB. So, if we are doing an edge
4246 insertion, don't do this dominance check. */
4248 && dominated_by_p (CDI_DOMINATORS, dest_bb, loc->bb))
4251 /* Otherwise, if E is not a critical edge and DEST_BB
4252 dominates the existing location for the assertion, move
4253 the assertion up in the dominance tree by updating its
4254 location information. */
4255 if ((e == NULL || !EDGE_CRITICAL_P (e))
4256 && dominated_by_p (CDI_DOMINATORS, loc->bb, dest_bb))
4265 /* Update the last node of the list and move to the next one. */
4270 /* If we didn't find an assertion already registered for
4271 NAME COMP_CODE VAL, add a new one at the end of the list of
4272 assertions associated with NAME. */
4273 n = XNEW (struct assert_locus_d);
4277 n->comp_code = comp_code;
4285 asserts_for[SSA_NAME_VERSION (name)] = n;
4287 bitmap_set_bit (need_assert_for, SSA_NAME_VERSION (name));
4290 /* (COND_OP0 COND_CODE COND_OP1) is a predicate which uses NAME.
4291 Extract a suitable test code and value and store them into *CODE_P and
4292 *VAL_P so the predicate is normalized to NAME *CODE_P *VAL_P.
4294 If no extraction was possible, return FALSE, otherwise return TRUE.
4296 If INVERT is true, then we invert the result stored into *CODE_P. */
4299 extract_code_and_val_from_cond_with_ops (tree name, enum tree_code cond_code,
4300 tree cond_op0, tree cond_op1,
4301 bool invert, enum tree_code *code_p,
4304 enum tree_code comp_code;
4307 /* Otherwise, we have a comparison of the form NAME COMP VAL
4308 or VAL COMP NAME. */
4309 if (name == cond_op1)
4311 /* If the predicate is of the form VAL COMP NAME, flip
4312 COMP around because we need to register NAME as the
4313 first operand in the predicate. */
4314 comp_code = swap_tree_comparison (cond_code);
4319 /* The comparison is of the form NAME COMP VAL, so the
4320 comparison code remains unchanged. */
4321 comp_code = cond_code;
4325 /* Invert the comparison code as necessary. */
4327 comp_code = invert_tree_comparison (comp_code, 0);
4329 /* VRP does not handle float types. */
4330 if (SCALAR_FLOAT_TYPE_P (TREE_TYPE (val)))
4333 /* Do not register always-false predicates.
4334 FIXME: this works around a limitation in fold() when dealing with
4335 enumerations. Given 'enum { N1, N2 } x;', fold will not
4336 fold 'if (x > N2)' to 'if (0)'. */
4337 if ((comp_code == GT_EXPR || comp_code == LT_EXPR)
4338 && INTEGRAL_TYPE_P (TREE_TYPE (val)))
4340 tree min = TYPE_MIN_VALUE (TREE_TYPE (val));
4341 tree max = TYPE_MAX_VALUE (TREE_TYPE (val));
4343 if (comp_code == GT_EXPR
4345 || compare_values (val, max) == 0))
4348 if (comp_code == LT_EXPR
4350 || compare_values (val, min) == 0))
4353 *code_p = comp_code;
4358 /* Try to register an edge assertion for SSA name NAME on edge E for
4359 the condition COND contributing to the conditional jump pointed to by BSI.
4360 Invert the condition COND if INVERT is true.
4361 Return true if an assertion for NAME could be registered. */
4364 register_edge_assert_for_2 (tree name, edge e, gimple_stmt_iterator bsi,
4365 enum tree_code cond_code,
4366 tree cond_op0, tree cond_op1, bool invert)
4369 enum tree_code comp_code;
4370 bool retval = false;
4372 if (!extract_code_and_val_from_cond_with_ops (name, cond_code,
4375 invert, &comp_code, &val))
4378 /* Only register an ASSERT_EXPR if NAME was found in the sub-graph
4379 reachable from E. */
4380 if (live_on_edge (e, name)
4381 && !has_single_use (name))
4383 register_new_assert_for (name, name, comp_code, val, NULL, e, bsi);
4387 /* In the case of NAME <= CST and NAME being defined as
4388 NAME = (unsigned) NAME2 + CST2 we can assert NAME2 >= -CST2
4389 and NAME2 <= CST - CST2. We can do the same for NAME > CST.
4390 This catches range and anti-range tests. */
4391 if ((comp_code == LE_EXPR
4392 || comp_code == GT_EXPR)
4393 && TREE_CODE (val) == INTEGER_CST
4394 && TYPE_UNSIGNED (TREE_TYPE (val)))
4396 gimple def_stmt = SSA_NAME_DEF_STMT (name);
4397 tree cst2 = NULL_TREE, name2 = NULL_TREE, name3 = NULL_TREE;
4399 /* Extract CST2 from the (optional) addition. */
4400 if (is_gimple_assign (def_stmt)
4401 && gimple_assign_rhs_code (def_stmt) == PLUS_EXPR)
4403 name2 = gimple_assign_rhs1 (def_stmt);
4404 cst2 = gimple_assign_rhs2 (def_stmt);
4405 if (TREE_CODE (name2) == SSA_NAME
4406 && TREE_CODE (cst2) == INTEGER_CST)
4407 def_stmt = SSA_NAME_DEF_STMT (name2);
4410 /* Extract NAME2 from the (optional) sign-changing cast. */
4411 if (gimple_assign_cast_p (def_stmt))
4413 if (CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (def_stmt))
4414 && ! TYPE_UNSIGNED (TREE_TYPE (gimple_assign_rhs1 (def_stmt)))
4415 && (TYPE_PRECISION (gimple_expr_type (def_stmt))
4416 == TYPE_PRECISION (TREE_TYPE (gimple_assign_rhs1 (def_stmt)))))
4417 name3 = gimple_assign_rhs1 (def_stmt);
4420 /* If name3 is used later, create an ASSERT_EXPR for it. */
4421 if (name3 != NULL_TREE
4422 && TREE_CODE (name3) == SSA_NAME
4423 && (cst2 == NULL_TREE
4424 || TREE_CODE (cst2) == INTEGER_CST)
4425 && INTEGRAL_TYPE_P (TREE_TYPE (name3))
4426 && live_on_edge (e, name3)
4427 && !has_single_use (name3))
4431 /* Build an expression for the range test. */
4432 tmp = build1 (NOP_EXPR, TREE_TYPE (name), name3);
4433 if (cst2 != NULL_TREE)
4434 tmp = build2 (PLUS_EXPR, TREE_TYPE (name), tmp, cst2);
4438 fprintf (dump_file, "Adding assert for ");
4439 print_generic_expr (dump_file, name3, 0);
4440 fprintf (dump_file, " from ");
4441 print_generic_expr (dump_file, tmp, 0);
4442 fprintf (dump_file, "\n");
4445 register_new_assert_for (name3, tmp, comp_code, val, NULL, e, bsi);
4450 /* If name2 is used later, create an ASSERT_EXPR for it. */
4451 if (name2 != NULL_TREE
4452 && TREE_CODE (name2) == SSA_NAME
4453 && TREE_CODE (cst2) == INTEGER_CST
4454 && INTEGRAL_TYPE_P (TREE_TYPE (name2))
4455 && live_on_edge (e, name2)
4456 && !has_single_use (name2))
4460 /* Build an expression for the range test. */
4462 if (TREE_TYPE (name) != TREE_TYPE (name2))
4463 tmp = build1 (NOP_EXPR, TREE_TYPE (name), tmp);
4464 if (cst2 != NULL_TREE)
4465 tmp = build2 (PLUS_EXPR, TREE_TYPE (name), tmp, cst2);
4469 fprintf (dump_file, "Adding assert for ");
4470 print_generic_expr (dump_file, name2, 0);
4471 fprintf (dump_file, " from ");
4472 print_generic_expr (dump_file, tmp, 0);
4473 fprintf (dump_file, "\n");
4476 register_new_assert_for (name2, tmp, comp_code, val, NULL, e, bsi);
4485 /* OP is an operand of a truth value expression which is known to have
4486 a particular value. Register any asserts for OP and for any
4487 operands in OP's defining statement.
4489 If CODE is EQ_EXPR, then we want to register OP is zero (false),
4490 if CODE is NE_EXPR, then we want to register OP is nonzero (true). */
4493 register_edge_assert_for_1 (tree op, enum tree_code code,
4494 edge e, gimple_stmt_iterator bsi)
4496 bool retval = false;
4499 enum tree_code rhs_code;
4501 /* We only care about SSA_NAMEs. */
4502 if (TREE_CODE (op) != SSA_NAME)
4505 /* We know that OP will have a zero or nonzero value. If OP is used
4506 more than once go ahead and register an assert for OP.
4508 The FOUND_IN_SUBGRAPH support is not helpful in this situation as
4509 it will always be set for OP (because OP is used in a COND_EXPR in
4511 if (!has_single_use (op))
4513 val = build_int_cst (TREE_TYPE (op), 0);
4514 register_new_assert_for (op, op, code, val, NULL, e, bsi);
4518 /* Now look at how OP is set. If it's set from a comparison,
4519 a truth operation or some bit operations, then we may be able
4520 to register information about the operands of that assignment. */
4521 op_def = SSA_NAME_DEF_STMT (op);
4522 if (gimple_code (op_def) != GIMPLE_ASSIGN)
4525 rhs_code = gimple_assign_rhs_code (op_def);
4527 if (TREE_CODE_CLASS (rhs_code) == tcc_comparison)
4529 bool invert = (code == EQ_EXPR ? true : false);
4530 tree op0 = gimple_assign_rhs1 (op_def);
4531 tree op1 = gimple_assign_rhs2 (op_def);
4533 if (TREE_CODE (op0) == SSA_NAME)
4534 retval |= register_edge_assert_for_2 (op0, e, bsi, rhs_code, op0, op1,
4536 if (TREE_CODE (op1) == SSA_NAME)
4537 retval |= register_edge_assert_for_2 (op1, e, bsi, rhs_code, op0, op1,
4540 else if ((code == NE_EXPR
4541 && gimple_assign_rhs_code (op_def) == BIT_AND_EXPR)
4543 && gimple_assign_rhs_code (op_def) == BIT_IOR_EXPR))
4545 /* Recurse on each operand. */
4546 retval |= register_edge_assert_for_1 (gimple_assign_rhs1 (op_def),
4548 retval |= register_edge_assert_for_1 (gimple_assign_rhs2 (op_def),
4551 else if (gimple_assign_rhs_code (op_def) == BIT_NOT_EXPR
4552 && TYPE_PRECISION (TREE_TYPE (gimple_assign_lhs (op_def))) == 1)
4554 /* Recurse, flipping CODE. */
4555 code = invert_tree_comparison (code, false);
4556 retval |= register_edge_assert_for_1 (gimple_assign_rhs1 (op_def),
4559 else if (gimple_assign_rhs_code (op_def) == SSA_NAME)
4561 /* Recurse through the copy. */
4562 retval |= register_edge_assert_for_1 (gimple_assign_rhs1 (op_def),
4565 else if (CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (op_def)))
4567 /* Recurse through the type conversion. */
4568 retval |= register_edge_assert_for_1 (gimple_assign_rhs1 (op_def),
4575 /* Try to register an edge assertion for SSA name NAME on edge E for
4576 the condition COND contributing to the conditional jump pointed to by SI.
4577 Return true if an assertion for NAME could be registered. */
4580 register_edge_assert_for (tree name, edge e, gimple_stmt_iterator si,
4581 enum tree_code cond_code, tree cond_op0,
4585 enum tree_code comp_code;
4586 bool retval = false;
4587 bool is_else_edge = (e->flags & EDGE_FALSE_VALUE) != 0;
4589 /* Do not attempt to infer anything in names that flow through
4591 if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (name))
4594 if (!extract_code_and_val_from_cond_with_ops (name, cond_code,
4600 /* Register ASSERT_EXPRs for name. */
4601 retval |= register_edge_assert_for_2 (name, e, si, cond_code, cond_op0,
4602 cond_op1, is_else_edge);
4605 /* If COND is effectively an equality test of an SSA_NAME against
4606 the value zero or one, then we may be able to assert values
4607 for SSA_NAMEs which flow into COND. */
4609 /* In the case of NAME == 1 or NAME != 0, for BIT_AND_EXPR defining
4610 statement of NAME we can assert both operands of the BIT_AND_EXPR
4611 have nonzero value. */
4612 if (((comp_code == EQ_EXPR && integer_onep (val))
4613 || (comp_code == NE_EXPR && integer_zerop (val))))
4615 gimple def_stmt = SSA_NAME_DEF_STMT (name);
4617 if (is_gimple_assign (def_stmt)
4618 && gimple_assign_rhs_code (def_stmt) == BIT_AND_EXPR)
4620 tree op0 = gimple_assign_rhs1 (def_stmt);
4621 tree op1 = gimple_assign_rhs2 (def_stmt);
4622 retval |= register_edge_assert_for_1 (op0, NE_EXPR, e, si);
4623 retval |= register_edge_assert_for_1 (op1, NE_EXPR, e, si);
4627 /* In the case of NAME == 0 or NAME != 1, for BIT_IOR_EXPR defining
4628 statement of NAME we can assert both operands of the BIT_IOR_EXPR
4630 if (((comp_code == EQ_EXPR && integer_zerop (val))
4631 || (comp_code == NE_EXPR && integer_onep (val))))
4633 gimple def_stmt = SSA_NAME_DEF_STMT (name);
4635 /* For BIT_IOR_EXPR only if NAME == 0 both operands have
4636 necessarily zero value, or if type-precision is one. */
4637 if (is_gimple_assign (def_stmt)
4638 && (gimple_assign_rhs_code (def_stmt) == BIT_IOR_EXPR
4639 && (TYPE_PRECISION (TREE_TYPE (name)) == 1
4640 || comp_code == EQ_EXPR)))
4642 tree op0 = gimple_assign_rhs1 (def_stmt);
4643 tree op1 = gimple_assign_rhs2 (def_stmt);
4644 retval |= register_edge_assert_for_1 (op0, EQ_EXPR, e, si);
4645 retval |= register_edge_assert_for_1 (op1, EQ_EXPR, e, si);
4653 /* Determine whether the outgoing edges of BB should receive an
4654 ASSERT_EXPR for each of the operands of BB's LAST statement.
4655 The last statement of BB must be a COND_EXPR.
4657 If any of the sub-graphs rooted at BB have an interesting use of
4658 the predicate operands, an assert location node is added to the
4659 list of assertions for the corresponding operands. */
4662 find_conditional_asserts (basic_block bb, gimple last)
4665 gimple_stmt_iterator bsi;
4671 need_assert = false;
4672 bsi = gsi_for_stmt (last);
4674 /* Look for uses of the operands in each of the sub-graphs
4675 rooted at BB. We need to check each of the outgoing edges
4676 separately, so that we know what kind of ASSERT_EXPR to
4678 FOR_EACH_EDGE (e, ei, bb->succs)
4683 /* Register the necessary assertions for each operand in the
4684 conditional predicate. */
4685 FOR_EACH_SSA_TREE_OPERAND (op, last, iter, SSA_OP_USE)
4687 need_assert |= register_edge_assert_for (op, e, bsi,
4688 gimple_cond_code (last),
4689 gimple_cond_lhs (last),
4690 gimple_cond_rhs (last));
4703 /* Compare two case labels sorting first by the destination bb index
4704 and then by the case value. */
4707 compare_case_labels (const void *p1, const void *p2)
4709 const struct case_info *ci1 = (const struct case_info *) p1;
4710 const struct case_info *ci2 = (const struct case_info *) p2;
4711 int idx1 = ci1->bb->index;
4712 int idx2 = ci2->bb->index;
4716 else if (idx1 == idx2)
4718 /* Make sure the default label is first in a group. */
4719 if (!CASE_LOW (ci1->expr))
4721 else if (!CASE_LOW (ci2->expr))
4724 return tree_int_cst_compare (CASE_LOW (ci1->expr),
4725 CASE_LOW (ci2->expr));
4731 /* Determine whether the outgoing edges of BB should receive an
4732 ASSERT_EXPR for each of the operands of BB's LAST statement.
4733 The last statement of BB must be a SWITCH_EXPR.
4735 If any of the sub-graphs rooted at BB have an interesting use of
4736 the predicate operands, an assert location node is added to the
4737 list of assertions for the corresponding operands. */
4740 find_switch_asserts (basic_block bb, gimple last)
4743 gimple_stmt_iterator bsi;
4746 struct case_info *ci;
4747 size_t n = gimple_switch_num_labels (last);
4748 #if GCC_VERSION >= 4000
4751 /* Work around GCC 3.4 bug (PR 37086). */
4752 volatile unsigned int idx;
4755 need_assert = false;
4756 bsi = gsi_for_stmt (last);
4757 op = gimple_switch_index (last);
4758 if (TREE_CODE (op) != SSA_NAME)
4761 /* Build a vector of case labels sorted by destination label. */
4762 ci = XNEWVEC (struct case_info, n);
4763 for (idx = 0; idx < n; ++idx)
4765 ci[idx].expr = gimple_switch_label (last, idx);
4766 ci[idx].bb = label_to_block (CASE_LABEL (ci[idx].expr));
4768 qsort (ci, n, sizeof (struct case_info), compare_case_labels);
4770 for (idx = 0; idx < n; ++idx)
4773 tree cl = ci[idx].expr;
4774 basic_block cbb = ci[idx].bb;
4776 min = CASE_LOW (cl);
4777 max = CASE_HIGH (cl);
4779 /* If there are multiple case labels with the same destination
4780 we need to combine them to a single value range for the edge. */
4781 if (idx + 1 < n && cbb == ci[idx + 1].bb)
4783 /* Skip labels until the last of the group. */
4786 } while (idx < n && cbb == ci[idx].bb);
4789 /* Pick up the maximum of the case label range. */
4790 if (CASE_HIGH (ci[idx].expr))
4791 max = CASE_HIGH (ci[idx].expr);
4793 max = CASE_LOW (ci[idx].expr);
4796 /* Nothing to do if the range includes the default label until we
4797 can register anti-ranges. */
4798 if (min == NULL_TREE)
4801 /* Find the edge to register the assert expr on. */
4802 e = find_edge (bb, cbb);
4804 /* Register the necessary assertions for the operand in the
4806 need_assert |= register_edge_assert_for (op, e, bsi,
4807 max ? GE_EXPR : EQ_EXPR,
4809 fold_convert (TREE_TYPE (op),
4813 need_assert |= register_edge_assert_for (op, e, bsi, LE_EXPR,
4815 fold_convert (TREE_TYPE (op),
4825 /* Traverse all the statements in block BB looking for statements that
4826 may generate useful assertions for the SSA names in their operand.
4827 If a statement produces a useful assertion A for name N_i, then the
4828 list of assertions already generated for N_i is scanned to
4829 determine if A is actually needed.
4831 If N_i already had the assertion A at a location dominating the
4832 current location, then nothing needs to be done. Otherwise, the
4833 new location for A is recorded instead.
4835 1- For every statement S in BB, all the variables used by S are
4836 added to bitmap FOUND_IN_SUBGRAPH.
4838 2- If statement S uses an operand N in a way that exposes a known
4839 value range for N, then if N was not already generated by an
4840 ASSERT_EXPR, create a new assert location for N. For instance,
4841 if N is a pointer and the statement dereferences it, we can
4842 assume that N is not NULL.
4844 3- COND_EXPRs are a special case of #2. We can derive range
4845 information from the predicate but need to insert different
4846 ASSERT_EXPRs for each of the sub-graphs rooted at the
4847 conditional block. If the last statement of BB is a conditional
4848 expression of the form 'X op Y', then
4850 a) Remove X and Y from the set FOUND_IN_SUBGRAPH.
4852 b) If the conditional is the only entry point to the sub-graph
4853 corresponding to the THEN_CLAUSE, recurse into it. On
4854 return, if X and/or Y are marked in FOUND_IN_SUBGRAPH, then
4855 an ASSERT_EXPR is added for the corresponding variable.
4857 c) Repeat step (b) on the ELSE_CLAUSE.
4859 d) Mark X and Y in FOUND_IN_SUBGRAPH.
4868 In this case, an assertion on the THEN clause is useful to
4869 determine that 'a' is always 9 on that edge. However, an assertion
4870 on the ELSE clause would be unnecessary.
4872 4- If BB does not end in a conditional expression, then we recurse
4873 into BB's dominator children.
4875 At the end of the recursive traversal, every SSA name will have a
4876 list of locations where ASSERT_EXPRs should be added. When a new
4877 location for name N is found, it is registered by calling
4878 register_new_assert_for. That function keeps track of all the
4879 registered assertions to prevent adding unnecessary assertions.
4880 For instance, if a pointer P_4 is dereferenced more than once in a
4881 dominator tree, only the location dominating all the dereference of
4882 P_4 will receive an ASSERT_EXPR.
4884 If this function returns true, then it means that there are names
4885 for which we need to generate ASSERT_EXPRs. Those assertions are
4886 inserted by process_assert_insertions. */
4889 find_assert_locations_1 (basic_block bb, sbitmap live)
4891 gimple_stmt_iterator si;
4896 need_assert = false;
4897 last = last_stmt (bb);
4899 /* If BB's last statement is a conditional statement involving integer
4900 operands, determine if we need to add ASSERT_EXPRs. */
4902 && gimple_code (last) == GIMPLE_COND
4903 && !fp_predicate (last)
4904 && !ZERO_SSA_OPERANDS (last, SSA_OP_USE))
4905 need_assert |= find_conditional_asserts (bb, last);
4907 /* If BB's last statement is a switch statement involving integer
4908 operands, determine if we need to add ASSERT_EXPRs. */
4910 && gimple_code (last) == GIMPLE_SWITCH
4911 && !ZERO_SSA_OPERANDS (last, SSA_OP_USE))
4912 need_assert |= find_switch_asserts (bb, last);
4914 /* Traverse all the statements in BB marking used names and looking
4915 for statements that may infer assertions for their used operands. */
4916 for (si = gsi_start_bb (bb); !gsi_end_p (si); gsi_next (&si))
4922 stmt = gsi_stmt (si);
4924 if (is_gimple_debug (stmt))
4927 /* See if we can derive an assertion for any of STMT's operands. */
4928 FOR_EACH_SSA_TREE_OPERAND (op, stmt, i, SSA_OP_USE)
4931 enum tree_code comp_code;
4933 /* Mark OP in our live bitmap. */
4934 SET_BIT (live, SSA_NAME_VERSION (op));
4936 /* If OP is used in such a way that we can infer a value
4937 range for it, and we don't find a previous assertion for
4938 it, create a new assertion location node for OP. */
4939 if (infer_value_range (stmt, op, &comp_code, &value))
4941 /* If we are able to infer a nonzero value range for OP,
4942 then walk backwards through the use-def chain to see if OP
4943 was set via a typecast.
4945 If so, then we can also infer a nonzero value range
4946 for the operand of the NOP_EXPR. */
4947 if (comp_code == NE_EXPR && integer_zerop (value))
4950 gimple def_stmt = SSA_NAME_DEF_STMT (t);
4952 while (is_gimple_assign (def_stmt)
4953 && gimple_assign_rhs_code (def_stmt) == NOP_EXPR
4955 (gimple_assign_rhs1 (def_stmt)) == SSA_NAME
4957 (TREE_TYPE (gimple_assign_rhs1 (def_stmt))))
4959 t = gimple_assign_rhs1 (def_stmt);
4960 def_stmt = SSA_NAME_DEF_STMT (t);
4962 /* Note we want to register the assert for the
4963 operand of the NOP_EXPR after SI, not after the
4965 if (! has_single_use (t))
4967 register_new_assert_for (t, t, comp_code, value,
4974 /* If OP is used only once, namely in this STMT, don't
4975 bother creating an ASSERT_EXPR for it. Such an
4976 ASSERT_EXPR would do nothing but increase compile time. */
4977 if (!has_single_use (op))
4979 register_new_assert_for (op, op, comp_code, value,
4987 /* Traverse all PHI nodes in BB marking used operands. */
4988 for (si = gsi_start_phis (bb); !gsi_end_p(si); gsi_next (&si))
4990 use_operand_p arg_p;
4992 phi = gsi_stmt (si);
4994 FOR_EACH_PHI_ARG (arg_p, phi, i, SSA_OP_USE)
4996 tree arg = USE_FROM_PTR (arg_p);
4997 if (TREE_CODE (arg) == SSA_NAME)
4998 SET_BIT (live, SSA_NAME_VERSION (arg));
5005 /* Do an RPO walk over the function computing SSA name liveness
5006 on-the-fly and deciding on assert expressions to insert.
5007 Returns true if there are assert expressions to be inserted. */
5010 find_assert_locations (void)
5012 int *rpo = XCNEWVEC (int, last_basic_block + NUM_FIXED_BLOCKS);
5013 int *bb_rpo = XCNEWVEC (int, last_basic_block + NUM_FIXED_BLOCKS);
5014 int *last_rpo = XCNEWVEC (int, last_basic_block + NUM_FIXED_BLOCKS);
5018 live = XCNEWVEC (sbitmap, last_basic_block + NUM_FIXED_BLOCKS);
5019 rpo_cnt = pre_and_rev_post_order_compute (NULL, rpo, false);
5020 for (i = 0; i < rpo_cnt; ++i)
5023 need_asserts = false;
5024 for (i = rpo_cnt-1; i >= 0; --i)
5026 basic_block bb = BASIC_BLOCK (rpo[i]);
5032 live[rpo[i]] = sbitmap_alloc (num_ssa_names);
5033 sbitmap_zero (live[rpo[i]]);
5036 /* Process BB and update the live information with uses in
5038 need_asserts |= find_assert_locations_1 (bb, live[rpo[i]]);
5040 /* Merge liveness into the predecessor blocks and free it. */
5041 if (!sbitmap_empty_p (live[rpo[i]]))
5044 FOR_EACH_EDGE (e, ei, bb->preds)
5046 int pred = e->src->index;
5047 if (e->flags & EDGE_DFS_BACK)
5052 live[pred] = sbitmap_alloc (num_ssa_names);
5053 sbitmap_zero (live[pred]);
5055 sbitmap_a_or_b (live[pred], live[pred], live[rpo[i]]);
5057 if (bb_rpo[pred] < pred_rpo)
5058 pred_rpo = bb_rpo[pred];
5061 /* Record the RPO number of the last visited block that needs
5062 live information from this block. */
5063 last_rpo[rpo[i]] = pred_rpo;
5067 sbitmap_free (live[rpo[i]]);
5068 live[rpo[i]] = NULL;
5071 /* We can free all successors live bitmaps if all their
5072 predecessors have been visited already. */
5073 FOR_EACH_EDGE (e, ei, bb->succs)
5074 if (last_rpo[e->dest->index] == i
5075 && live[e->dest->index])
5077 sbitmap_free (live[e->dest->index]);
5078 live[e->dest->index] = NULL;
5083 XDELETEVEC (bb_rpo);
5084 XDELETEVEC (last_rpo);
5085 for (i = 0; i < last_basic_block + NUM_FIXED_BLOCKS; ++i)
5087 sbitmap_free (live[i]);
5090 return need_asserts;
5093 /* Create an ASSERT_EXPR for NAME and insert it in the location
5094 indicated by LOC. Return true if we made any edge insertions. */
5097 process_assert_insertions_for (tree name, assert_locus_t loc)
5099 /* Build the comparison expression NAME_i COMP_CODE VAL. */
5106 /* If we have X <=> X do not insert an assert expr for that. */
5107 if (loc->expr == loc->val)
5110 cond = build2 (loc->comp_code, boolean_type_node, loc->expr, loc->val);
5111 assert_stmt = build_assert_expr_for (cond, name);
5114 /* We have been asked to insert the assertion on an edge. This
5115 is used only by COND_EXPR and SWITCH_EXPR assertions. */
5116 gcc_checking_assert (gimple_code (gsi_stmt (loc->si)) == GIMPLE_COND
5117 || (gimple_code (gsi_stmt (loc->si))
5120 gsi_insert_on_edge (loc->e, assert_stmt);
5124 /* Otherwise, we can insert right after LOC->SI iff the
5125 statement must not be the last statement in the block. */
5126 stmt = gsi_stmt (loc->si);
5127 if (!stmt_ends_bb_p (stmt))
5129 gsi_insert_after (&loc->si, assert_stmt, GSI_SAME_STMT);
5133 /* If STMT must be the last statement in BB, we can only insert new
5134 assertions on the non-abnormal edge out of BB. Note that since
5135 STMT is not control flow, there may only be one non-abnormal edge
5137 FOR_EACH_EDGE (e, ei, loc->bb->succs)
5138 if (!(e->flags & EDGE_ABNORMAL))
5140 gsi_insert_on_edge (e, assert_stmt);
5148 /* Process all the insertions registered for every name N_i registered
5149 in NEED_ASSERT_FOR. The list of assertions to be inserted are
5150 found in ASSERTS_FOR[i]. */
5153 process_assert_insertions (void)
5157 bool update_edges_p = false;
5158 int num_asserts = 0;
5160 if (dump_file && (dump_flags & TDF_DETAILS))
5161 dump_all_asserts (dump_file);
5163 EXECUTE_IF_SET_IN_BITMAP (need_assert_for, 0, i, bi)
5165 assert_locus_t loc = asserts_for[i];
5170 assert_locus_t next = loc->next;
5171 update_edges_p |= process_assert_insertions_for (ssa_name (i), loc);
5179 gsi_commit_edge_inserts ();
5181 statistics_counter_event (cfun, "Number of ASSERT_EXPR expressions inserted",
5186 /* Traverse the flowgraph looking for conditional jumps to insert range
5187 expressions. These range expressions are meant to provide information
5188 to optimizations that need to reason in terms of value ranges. They
5189 will not be expanded into RTL. For instance, given:
5198 this pass will transform the code into:
5204 x = ASSERT_EXPR <x, x < y>
5209 y = ASSERT_EXPR <y, x <= y>
5213 The idea is that once copy and constant propagation have run, other
5214 optimizations will be able to determine what ranges of values can 'x'
5215 take in different paths of the code, simply by checking the reaching
5216 definition of 'x'. */
5219 insert_range_assertions (void)
5221 need_assert_for = BITMAP_ALLOC (NULL);
5222 asserts_for = XCNEWVEC (assert_locus_t, num_ssa_names);
5224 calculate_dominance_info (CDI_DOMINATORS);
5226 if (find_assert_locations ())
5228 process_assert_insertions ();
5229 update_ssa (TODO_update_ssa_no_phi);
5232 if (dump_file && (dump_flags & TDF_DETAILS))
5234 fprintf (dump_file, "\nSSA form after inserting ASSERT_EXPRs\n");
5235 dump_function_to_file (current_function_decl, dump_file, dump_flags);
5239 BITMAP_FREE (need_assert_for);
5242 /* Checks one ARRAY_REF in REF, located at LOCUS. Ignores flexible arrays
5243 and "struct" hacks. If VRP can determine that the
5244 array subscript is a constant, check if it is outside valid
5245 range. If the array subscript is a RANGE, warn if it is
5246 non-overlapping with valid range.
5247 IGNORE_OFF_BY_ONE is true if the ARRAY_REF is inside a ADDR_EXPR. */
5250 check_array_ref (location_t location, tree ref, bool ignore_off_by_one)
5252 value_range_t* vr = NULL;
5253 tree low_sub, up_sub;
5254 tree low_bound, up_bound, up_bound_p1;
5257 if (TREE_NO_WARNING (ref))
5260 low_sub = up_sub = TREE_OPERAND (ref, 1);
5261 up_bound = array_ref_up_bound (ref);
5263 /* Can not check flexible arrays. */
5265 || TREE_CODE (up_bound) != INTEGER_CST)
5268 /* Accesses to trailing arrays via pointers may access storage
5269 beyond the types array bounds. */
5270 base = get_base_address (ref);
5271 if (base && TREE_CODE (base) == MEM_REF)
5273 tree cref, next = NULL_TREE;
5275 if (TREE_CODE (TREE_OPERAND (ref, 0)) != COMPONENT_REF)
5278 cref = TREE_OPERAND (ref, 0);
5279 if (TREE_CODE (TREE_TYPE (TREE_OPERAND (cref, 0))) == RECORD_TYPE)
5280 for (next = DECL_CHAIN (TREE_OPERAND (cref, 1));
5281 next && TREE_CODE (next) != FIELD_DECL;
5282 next = DECL_CHAIN (next))
5285 /* If this is the last field in a struct type or a field in a
5286 union type do not warn. */
5291 low_bound = array_ref_low_bound (ref);
5292 up_bound_p1 = int_const_binop (PLUS_EXPR, up_bound, integer_one_node);
5294 if (TREE_CODE (low_sub) == SSA_NAME)
5296 vr = get_value_range (low_sub);
5297 if (vr->type == VR_RANGE || vr->type == VR_ANTI_RANGE)
5299 low_sub = vr->type == VR_RANGE ? vr->max : vr->min;
5300 up_sub = vr->type == VR_RANGE ? vr->min : vr->max;
5304 if (vr && vr->type == VR_ANTI_RANGE)
5306 if (TREE_CODE (up_sub) == INTEGER_CST
5307 && tree_int_cst_lt (up_bound, up_sub)
5308 && TREE_CODE (low_sub) == INTEGER_CST
5309 && tree_int_cst_lt (low_sub, low_bound))
5311 warning_at (location, OPT_Warray_bounds,
5312 "array subscript is outside array bounds");
5313 TREE_NO_WARNING (ref) = 1;
5316 else if (TREE_CODE (up_sub) == INTEGER_CST
5317 && (ignore_off_by_one
5318 ? (tree_int_cst_lt (up_bound, up_sub)
5319 && !tree_int_cst_equal (up_bound_p1, up_sub))
5320 : (tree_int_cst_lt (up_bound, up_sub)
5321 || tree_int_cst_equal (up_bound_p1, up_sub))))
5323 warning_at (location, OPT_Warray_bounds,
5324 "array subscript is above array bounds");
5325 TREE_NO_WARNING (ref) = 1;
5327 else if (TREE_CODE (low_sub) == INTEGER_CST
5328 && tree_int_cst_lt (low_sub, low_bound))
5330 warning_at (location, OPT_Warray_bounds,
5331 "array subscript is below array bounds");
5332 TREE_NO_WARNING (ref) = 1;
5336 /* Searches if the expr T, located at LOCATION computes
5337 address of an ARRAY_REF, and call check_array_ref on it. */
5340 search_for_addr_array (tree t, location_t location)
5342 while (TREE_CODE (t) == SSA_NAME)
5344 gimple g = SSA_NAME_DEF_STMT (t);
5346 if (gimple_code (g) != GIMPLE_ASSIGN)
5349 if (get_gimple_rhs_class (gimple_assign_rhs_code (g))
5350 != GIMPLE_SINGLE_RHS)
5353 t = gimple_assign_rhs1 (g);
5357 /* We are only interested in addresses of ARRAY_REF's. */
5358 if (TREE_CODE (t) != ADDR_EXPR)
5361 /* Check each ARRAY_REFs in the reference chain. */
5364 if (TREE_CODE (t) == ARRAY_REF)
5365 check_array_ref (location, t, true /*ignore_off_by_one*/);
5367 t = TREE_OPERAND (t, 0);
5369 while (handled_component_p (t));
5371 if (TREE_CODE (t) == MEM_REF
5372 && TREE_CODE (TREE_OPERAND (t, 0)) == ADDR_EXPR
5373 && !TREE_NO_WARNING (t))
5375 tree tem = TREE_OPERAND (TREE_OPERAND (t, 0), 0);
5376 tree low_bound, up_bound, el_sz;
5378 if (TREE_CODE (TREE_TYPE (tem)) != ARRAY_TYPE
5379 || TREE_CODE (TREE_TYPE (TREE_TYPE (tem))) == ARRAY_TYPE
5380 || !TYPE_DOMAIN (TREE_TYPE (tem)))
5383 low_bound = TYPE_MIN_VALUE (TYPE_DOMAIN (TREE_TYPE (tem)));
5384 up_bound = TYPE_MAX_VALUE (TYPE_DOMAIN (TREE_TYPE (tem)));
5385 el_sz = TYPE_SIZE_UNIT (TREE_TYPE (TREE_TYPE (tem)));
5387 || TREE_CODE (low_bound) != INTEGER_CST
5389 || TREE_CODE (up_bound) != INTEGER_CST
5391 || TREE_CODE (el_sz) != INTEGER_CST)
5394 idx = mem_ref_offset (t);
5395 idx = double_int_sdiv (idx, tree_to_double_int (el_sz), TRUNC_DIV_EXPR);
5396 if (double_int_scmp (idx, double_int_zero) < 0)
5398 warning_at (location, OPT_Warray_bounds,
5399 "array subscript is below array bounds");
5400 TREE_NO_WARNING (t) = 1;
5402 else if (double_int_scmp (idx,
5405 (tree_to_double_int (up_bound),
5407 (tree_to_double_int (low_bound))),
5408 double_int_one)) > 0)
5410 warning_at (location, OPT_Warray_bounds,
5411 "array subscript is above array bounds");
5412 TREE_NO_WARNING (t) = 1;
5417 /* walk_tree() callback that checks if *TP is
5418 an ARRAY_REF inside an ADDR_EXPR (in which an array
5419 subscript one outside the valid range is allowed). Call
5420 check_array_ref for each ARRAY_REF found. The location is
5424 check_array_bounds (tree *tp, int *walk_subtree, void *data)
5427 struct walk_stmt_info *wi = (struct walk_stmt_info *) data;
5428 location_t location;
5430 if (EXPR_HAS_LOCATION (t))
5431 location = EXPR_LOCATION (t);
5434 location_t *locp = (location_t *) wi->info;
5438 *walk_subtree = TRUE;
5440 if (TREE_CODE (t) == ARRAY_REF)
5441 check_array_ref (location, t, false /*ignore_off_by_one*/);
5443 if (TREE_CODE (t) == MEM_REF
5444 || (TREE_CODE (t) == RETURN_EXPR && TREE_OPERAND (t, 0)))
5445 search_for_addr_array (TREE_OPERAND (t, 0), location);
5447 if (TREE_CODE (t) == ADDR_EXPR)
5448 *walk_subtree = FALSE;
5453 /* Walk over all statements of all reachable BBs and call check_array_bounds
5457 check_all_array_refs (void)
5460 gimple_stmt_iterator si;
5466 bool executable = false;
5468 /* Skip blocks that were found to be unreachable. */
5469 FOR_EACH_EDGE (e, ei, bb->preds)
5470 executable |= !!(e->flags & EDGE_EXECUTABLE);
5474 for (si = gsi_start_bb (bb); !gsi_end_p (si); gsi_next (&si))
5476 gimple stmt = gsi_stmt (si);
5477 struct walk_stmt_info wi;
5478 if (!gimple_has_location (stmt))
5481 if (is_gimple_call (stmt))
5484 size_t n = gimple_call_num_args (stmt);
5485 for (i = 0; i < n; i++)
5487 tree arg = gimple_call_arg (stmt, i);
5488 search_for_addr_array (arg, gimple_location (stmt));
5493 memset (&wi, 0, sizeof (wi));
5494 wi.info = CONST_CAST (void *, (const void *)
5495 gimple_location_ptr (stmt));
5497 walk_gimple_op (gsi_stmt (si),
5505 /* Convert range assertion expressions into the implied copies and
5506 copy propagate away the copies. Doing the trivial copy propagation
5507 here avoids the need to run the full copy propagation pass after
5510 FIXME, this will eventually lead to copy propagation removing the
5511 names that had useful range information attached to them. For
5512 instance, if we had the assertion N_i = ASSERT_EXPR <N_j, N_j > 3>,
5513 then N_i will have the range [3, +INF].
5515 However, by converting the assertion into the implied copy
5516 operation N_i = N_j, we will then copy-propagate N_j into the uses
5517 of N_i and lose the range information. We may want to hold on to
5518 ASSERT_EXPRs a little while longer as the ranges could be used in
5519 things like jump threading.
5521 The problem with keeping ASSERT_EXPRs around is that passes after
5522 VRP need to handle them appropriately.
5524 Another approach would be to make the range information a first
5525 class property of the SSA_NAME so that it can be queried from
5526 any pass. This is made somewhat more complex by the need for
5527 multiple ranges to be associated with one SSA_NAME. */
5530 remove_range_assertions (void)
5533 gimple_stmt_iterator si;
5535 /* Note that the BSI iterator bump happens at the bottom of the
5536 loop and no bump is necessary if we're removing the statement
5537 referenced by the current BSI. */
5539 for (si = gsi_start_bb (bb); !gsi_end_p (si);)
5541 gimple stmt = gsi_stmt (si);
5544 if (is_gimple_assign (stmt)
5545 && gimple_assign_rhs_code (stmt) == ASSERT_EXPR)
5547 tree rhs = gimple_assign_rhs1 (stmt);
5549 tree cond = fold (ASSERT_EXPR_COND (rhs));
5550 use_operand_p use_p;
5551 imm_use_iterator iter;
5553 gcc_assert (cond != boolean_false_node);
5555 /* Propagate the RHS into every use of the LHS. */
5556 var = ASSERT_EXPR_VAR (rhs);
5557 FOR_EACH_IMM_USE_STMT (use_stmt, iter,
5558 gimple_assign_lhs (stmt))
5559 FOR_EACH_IMM_USE_ON_STMT (use_p, iter)
5561 SET_USE (use_p, var);
5562 gcc_assert (TREE_CODE (var) == SSA_NAME);
5565 /* And finally, remove the copy, it is not needed. */
5566 gsi_remove (&si, true);
5567 release_defs (stmt);
5575 /* Return true if STMT is interesting for VRP. */
5578 stmt_interesting_for_vrp (gimple stmt)
5580 if (gimple_code (stmt) == GIMPLE_PHI
5581 && is_gimple_reg (gimple_phi_result (stmt))
5582 && (INTEGRAL_TYPE_P (TREE_TYPE (gimple_phi_result (stmt)))
5583 || POINTER_TYPE_P (TREE_TYPE (gimple_phi_result (stmt)))))
5585 else if (is_gimple_assign (stmt) || is_gimple_call (stmt))
5587 tree lhs = gimple_get_lhs (stmt);
5589 /* In general, assignments with virtual operands are not useful
5590 for deriving ranges, with the obvious exception of calls to
5591 builtin functions. */
5592 if (lhs && TREE_CODE (lhs) == SSA_NAME
5593 && (INTEGRAL_TYPE_P (TREE_TYPE (lhs))
5594 || POINTER_TYPE_P (TREE_TYPE (lhs)))
5595 && ((is_gimple_call (stmt)
5596 && gimple_call_fndecl (stmt) != NULL_TREE
5597 && DECL_IS_BUILTIN (gimple_call_fndecl (stmt)))
5598 || !gimple_vuse (stmt)))
5601 else if (gimple_code (stmt) == GIMPLE_COND
5602 || gimple_code (stmt) == GIMPLE_SWITCH)
5609 /* Initialize local data structures for VRP. */
5612 vrp_initialize (void)
5616 values_propagated = false;
5617 num_vr_values = num_ssa_names;
5618 vr_value = XCNEWVEC (value_range_t *, num_vr_values);
5619 vr_phi_edge_counts = XCNEWVEC (int, num_ssa_names);
5623 gimple_stmt_iterator si;
5625 for (si = gsi_start_phis (bb); !gsi_end_p (si); gsi_next (&si))
5627 gimple phi = gsi_stmt (si);
5628 if (!stmt_interesting_for_vrp (phi))
5630 tree lhs = PHI_RESULT (phi);
5631 set_value_range_to_varying (get_value_range (lhs));
5632 prop_set_simulate_again (phi, false);
5635 prop_set_simulate_again (phi, true);
5638 for (si = gsi_start_bb (bb); !gsi_end_p (si); gsi_next (&si))
5640 gimple stmt = gsi_stmt (si);
5642 /* If the statement is a control insn, then we do not
5643 want to avoid simulating the statement once. Failure
5644 to do so means that those edges will never get added. */
5645 if (stmt_ends_bb_p (stmt))
5646 prop_set_simulate_again (stmt, true);
5647 else if (!stmt_interesting_for_vrp (stmt))
5651 FOR_EACH_SSA_TREE_OPERAND (def, stmt, i, SSA_OP_DEF)
5652 set_value_range_to_varying (get_value_range (def));
5653 prop_set_simulate_again (stmt, false);
5656 prop_set_simulate_again (stmt, true);
5661 /* Return the singleton value-range for NAME or NAME. */
5664 vrp_valueize (tree name)
5666 if (TREE_CODE (name) == SSA_NAME)
5668 value_range_t *vr = get_value_range (name);
5669 if (vr->type == VR_RANGE
5670 && (vr->min == vr->max
5671 || operand_equal_p (vr->min, vr->max, 0)))
5677 /* Visit assignment STMT. If it produces an interesting range, record
5678 the SSA name in *OUTPUT_P. */
5680 static enum ssa_prop_result
5681 vrp_visit_assignment_or_call (gimple stmt, tree *output_p)
5685 enum gimple_code code = gimple_code (stmt);
5686 lhs = gimple_get_lhs (stmt);
5688 /* We only keep track of ranges in integral and pointer types. */
5689 if (TREE_CODE (lhs) == SSA_NAME
5690 && ((INTEGRAL_TYPE_P (TREE_TYPE (lhs))
5691 /* It is valid to have NULL MIN/MAX values on a type. See
5692 build_range_type. */
5693 && TYPE_MIN_VALUE (TREE_TYPE (lhs))
5694 && TYPE_MAX_VALUE (TREE_TYPE (lhs)))
5695 || POINTER_TYPE_P (TREE_TYPE (lhs))))
5697 value_range_t new_vr = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
5699 /* Try folding the statement to a constant first. */
5700 tree tem = gimple_fold_stmt_to_constant (stmt, vrp_valueize);
5701 if (tem && !is_overflow_infinity (tem))
5702 set_value_range (&new_vr, VR_RANGE, tem, tem, NULL);
5703 /* Then dispatch to value-range extracting functions. */
5704 else if (code == GIMPLE_CALL)
5705 extract_range_basic (&new_vr, stmt);
5707 extract_range_from_assignment (&new_vr, stmt);
5709 if (update_value_range (lhs, &new_vr))
5713 if (dump_file && (dump_flags & TDF_DETAILS))
5715 fprintf (dump_file, "Found new range for ");
5716 print_generic_expr (dump_file, lhs, 0);
5717 fprintf (dump_file, ": ");
5718 dump_value_range (dump_file, &new_vr);
5719 fprintf (dump_file, "\n\n");
5722 if (new_vr.type == VR_VARYING)
5723 return SSA_PROP_VARYING;
5725 return SSA_PROP_INTERESTING;
5728 return SSA_PROP_NOT_INTERESTING;
5731 /* Every other statement produces no useful ranges. */
5732 FOR_EACH_SSA_TREE_OPERAND (def, stmt, iter, SSA_OP_DEF)
5733 set_value_range_to_varying (get_value_range (def));
5735 return SSA_PROP_VARYING;
5738 /* Helper that gets the value range of the SSA_NAME with version I
5739 or a symbolic range containing the SSA_NAME only if the value range
5740 is varying or undefined. */
5742 static inline value_range_t
5743 get_vr_for_comparison (int i)
5745 value_range_t vr = *get_value_range (ssa_name (i));
5747 /* If name N_i does not have a valid range, use N_i as its own
5748 range. This allows us to compare against names that may
5749 have N_i in their ranges. */
5750 if (vr.type == VR_VARYING || vr.type == VR_UNDEFINED)
5753 vr.min = ssa_name (i);
5754 vr.max = ssa_name (i);
5760 /* Compare all the value ranges for names equivalent to VAR with VAL
5761 using comparison code COMP. Return the same value returned by
5762 compare_range_with_value, including the setting of
5763 *STRICT_OVERFLOW_P. */
5766 compare_name_with_value (enum tree_code comp, tree var, tree val,
5767 bool *strict_overflow_p)
5773 int used_strict_overflow;
5775 value_range_t equiv_vr;
5777 /* Get the set of equivalences for VAR. */
5778 e = get_value_range (var)->equiv;
5780 /* Start at -1. Set it to 0 if we do a comparison without relying
5781 on overflow, or 1 if all comparisons rely on overflow. */
5782 used_strict_overflow = -1;
5784 /* Compare vars' value range with val. */
5785 equiv_vr = get_vr_for_comparison (SSA_NAME_VERSION (var));
5787 retval = compare_range_with_value (comp, &equiv_vr, val, &sop);
5789 used_strict_overflow = sop ? 1 : 0;
5791 /* If the equiv set is empty we have done all work we need to do. */
5795 && used_strict_overflow > 0)
5796 *strict_overflow_p = true;
5800 EXECUTE_IF_SET_IN_BITMAP (e, 0, i, bi)
5802 equiv_vr = get_vr_for_comparison (i);
5804 t = compare_range_with_value (comp, &equiv_vr, val, &sop);
5807 /* If we get different answers from different members
5808 of the equivalence set this check must be in a dead
5809 code region. Folding it to a trap representation
5810 would be correct here. For now just return don't-know. */
5820 used_strict_overflow = 0;
5821 else if (used_strict_overflow < 0)
5822 used_strict_overflow = 1;
5827 && used_strict_overflow > 0)
5828 *strict_overflow_p = true;
5834 /* Given a comparison code COMP and names N1 and N2, compare all the
5835 ranges equivalent to N1 against all the ranges equivalent to N2
5836 to determine the value of N1 COMP N2. Return the same value
5837 returned by compare_ranges. Set *STRICT_OVERFLOW_P to indicate
5838 whether we relied on an overflow infinity in the comparison. */
5842 compare_names (enum tree_code comp, tree n1, tree n2,
5843 bool *strict_overflow_p)
5847 bitmap_iterator bi1, bi2;
5849 int used_strict_overflow;
5850 static bitmap_obstack *s_obstack = NULL;
5851 static bitmap s_e1 = NULL, s_e2 = NULL;
5853 /* Compare the ranges of every name equivalent to N1 against the
5854 ranges of every name equivalent to N2. */
5855 e1 = get_value_range (n1)->equiv;
5856 e2 = get_value_range (n2)->equiv;
5858 /* Use the fake bitmaps if e1 or e2 are not available. */
5859 if (s_obstack == NULL)
5861 s_obstack = XNEW (bitmap_obstack);
5862 bitmap_obstack_initialize (s_obstack);
5863 s_e1 = BITMAP_ALLOC (s_obstack);
5864 s_e2 = BITMAP_ALLOC (s_obstack);
5871 /* Add N1 and N2 to their own set of equivalences to avoid
5872 duplicating the body of the loop just to check N1 and N2
5874 bitmap_set_bit (e1, SSA_NAME_VERSION (n1));
5875 bitmap_set_bit (e2, SSA_NAME_VERSION (n2));
5877 /* If the equivalence sets have a common intersection, then the two
5878 names can be compared without checking their ranges. */
5879 if (bitmap_intersect_p (e1, e2))
5881 bitmap_clear_bit (e1, SSA_NAME_VERSION (n1));
5882 bitmap_clear_bit (e2, SSA_NAME_VERSION (n2));
5884 return (comp == EQ_EXPR || comp == GE_EXPR || comp == LE_EXPR)
5886 : boolean_false_node;
5889 /* Start at -1. Set it to 0 if we do a comparison without relying
5890 on overflow, or 1 if all comparisons rely on overflow. */
5891 used_strict_overflow = -1;
5893 /* Otherwise, compare all the equivalent ranges. First, add N1 and
5894 N2 to their own set of equivalences to avoid duplicating the body
5895 of the loop just to check N1 and N2 ranges. */
5896 EXECUTE_IF_SET_IN_BITMAP (e1, 0, i1, bi1)
5898 value_range_t vr1 = get_vr_for_comparison (i1);
5900 t = retval = NULL_TREE;
5901 EXECUTE_IF_SET_IN_BITMAP (e2, 0, i2, bi2)
5905 value_range_t vr2 = get_vr_for_comparison (i2);
5907 t = compare_ranges (comp, &vr1, &vr2, &sop);
5910 /* If we get different answers from different members
5911 of the equivalence set this check must be in a dead
5912 code region. Folding it to a trap representation
5913 would be correct here. For now just return don't-know. */
5917 bitmap_clear_bit (e1, SSA_NAME_VERSION (n1));
5918 bitmap_clear_bit (e2, SSA_NAME_VERSION (n2));
5924 used_strict_overflow = 0;
5925 else if (used_strict_overflow < 0)
5926 used_strict_overflow = 1;
5932 bitmap_clear_bit (e1, SSA_NAME_VERSION (n1));
5933 bitmap_clear_bit (e2, SSA_NAME_VERSION (n2));
5934 if (used_strict_overflow > 0)
5935 *strict_overflow_p = true;
5940 /* None of the equivalent ranges are useful in computing this
5942 bitmap_clear_bit (e1, SSA_NAME_VERSION (n1));
5943 bitmap_clear_bit (e2, SSA_NAME_VERSION (n2));
5947 /* Helper function for vrp_evaluate_conditional_warnv. */
5950 vrp_evaluate_conditional_warnv_with_ops_using_ranges (enum tree_code code,
5952 bool * strict_overflow_p)
5954 value_range_t *vr0, *vr1;
5956 vr0 = (TREE_CODE (op0) == SSA_NAME) ? get_value_range (op0) : NULL;
5957 vr1 = (TREE_CODE (op1) == SSA_NAME) ? get_value_range (op1) : NULL;
5960 return compare_ranges (code, vr0, vr1, strict_overflow_p);
5961 else if (vr0 && vr1 == NULL)
5962 return compare_range_with_value (code, vr0, op1, strict_overflow_p);
5963 else if (vr0 == NULL && vr1)
5964 return (compare_range_with_value
5965 (swap_tree_comparison (code), vr1, op0, strict_overflow_p));
5969 /* Helper function for vrp_evaluate_conditional_warnv. */
5972 vrp_evaluate_conditional_warnv_with_ops (enum tree_code code, tree op0,
5973 tree op1, bool use_equiv_p,
5974 bool *strict_overflow_p, bool *only_ranges)
5978 *only_ranges = true;
5980 /* We only deal with integral and pointer types. */
5981 if (!INTEGRAL_TYPE_P (TREE_TYPE (op0))
5982 && !POINTER_TYPE_P (TREE_TYPE (op0)))
5988 && (ret = vrp_evaluate_conditional_warnv_with_ops_using_ranges
5989 (code, op0, op1, strict_overflow_p)))
5991 *only_ranges = false;
5992 if (TREE_CODE (op0) == SSA_NAME && TREE_CODE (op1) == SSA_NAME)
5993 return compare_names (code, op0, op1, strict_overflow_p);
5994 else if (TREE_CODE (op0) == SSA_NAME)
5995 return compare_name_with_value (code, op0, op1, strict_overflow_p);
5996 else if (TREE_CODE (op1) == SSA_NAME)
5997 return (compare_name_with_value
5998 (swap_tree_comparison (code), op1, op0, strict_overflow_p));
6001 return vrp_evaluate_conditional_warnv_with_ops_using_ranges (code, op0, op1,
6006 /* Given (CODE OP0 OP1) within STMT, try to simplify it based on value range
6007 information. Return NULL if the conditional can not be evaluated.
6008 The ranges of all the names equivalent with the operands in COND
6009 will be used when trying to compute the value. If the result is
6010 based on undefined signed overflow, issue a warning if
6014 vrp_evaluate_conditional (enum tree_code code, tree op0, tree op1, gimple stmt)
6020 /* Some passes and foldings leak constants with overflow flag set
6021 into the IL. Avoid doing wrong things with these and bail out. */
6022 if ((TREE_CODE (op0) == INTEGER_CST
6023 && TREE_OVERFLOW (op0))
6024 || (TREE_CODE (op1) == INTEGER_CST
6025 && TREE_OVERFLOW (op1)))
6029 ret = vrp_evaluate_conditional_warnv_with_ops (code, op0, op1, true, &sop,
6034 enum warn_strict_overflow_code wc;
6035 const char* warnmsg;
6037 if (is_gimple_min_invariant (ret))
6039 wc = WARN_STRICT_OVERFLOW_CONDITIONAL;
6040 warnmsg = G_("assuming signed overflow does not occur when "
6041 "simplifying conditional to constant");
6045 wc = WARN_STRICT_OVERFLOW_COMPARISON;
6046 warnmsg = G_("assuming signed overflow does not occur when "
6047 "simplifying conditional");
6050 if (issue_strict_overflow_warning (wc))
6052 location_t location;
6054 if (!gimple_has_location (stmt))
6055 location = input_location;
6057 location = gimple_location (stmt);
6058 warning_at (location, OPT_Wstrict_overflow, "%s", warnmsg);
6062 if (warn_type_limits
6063 && ret && only_ranges
6064 && TREE_CODE_CLASS (code) == tcc_comparison
6065 && TREE_CODE (op0) == SSA_NAME)
6067 /* If the comparison is being folded and the operand on the LHS
6068 is being compared against a constant value that is outside of
6069 the natural range of OP0's type, then the predicate will
6070 always fold regardless of the value of OP0. If -Wtype-limits
6071 was specified, emit a warning. */
6072 tree type = TREE_TYPE (op0);
6073 value_range_t *vr0 = get_value_range (op0);
6075 if (vr0->type != VR_VARYING
6076 && INTEGRAL_TYPE_P (type)
6077 && vrp_val_is_min (vr0->min)
6078 && vrp_val_is_max (vr0->max)
6079 && is_gimple_min_invariant (op1))
6081 location_t location;
6083 if (!gimple_has_location (stmt))
6084 location = input_location;
6086 location = gimple_location (stmt);
6088 warning_at (location, OPT_Wtype_limits,
6090 ? G_("comparison always false "
6091 "due to limited range of data type")
6092 : G_("comparison always true "
6093 "due to limited range of data type"));
6101 /* Visit conditional statement STMT. If we can determine which edge
6102 will be taken out of STMT's basic block, record it in
6103 *TAKEN_EDGE_P and return SSA_PROP_INTERESTING. Otherwise, return
6104 SSA_PROP_VARYING. */
6106 static enum ssa_prop_result
6107 vrp_visit_cond_stmt (gimple stmt, edge *taken_edge_p)
6112 *taken_edge_p = NULL;
6114 if (dump_file && (dump_flags & TDF_DETAILS))
6119 fprintf (dump_file, "\nVisiting conditional with predicate: ");
6120 print_gimple_stmt (dump_file, stmt, 0, 0);
6121 fprintf (dump_file, "\nWith known ranges\n");
6123 FOR_EACH_SSA_TREE_OPERAND (use, stmt, i, SSA_OP_USE)
6125 fprintf (dump_file, "\t");
6126 print_generic_expr (dump_file, use, 0);
6127 fprintf (dump_file, ": ");
6128 dump_value_range (dump_file, vr_value[SSA_NAME_VERSION (use)]);
6131 fprintf (dump_file, "\n");
6134 /* Compute the value of the predicate COND by checking the known
6135 ranges of each of its operands.
6137 Note that we cannot evaluate all the equivalent ranges here
6138 because those ranges may not yet be final and with the current
6139 propagation strategy, we cannot determine when the value ranges
6140 of the names in the equivalence set have changed.
6142 For instance, given the following code fragment
6146 i_14 = ASSERT_EXPR <i_5, i_5 != 0>
6150 Assume that on the first visit to i_14, i_5 has the temporary
6151 range [8, 8] because the second argument to the PHI function is
6152 not yet executable. We derive the range ~[0, 0] for i_14 and the
6153 equivalence set { i_5 }. So, when we visit 'if (i_14 == 1)' for
6154 the first time, since i_14 is equivalent to the range [8, 8], we
6155 determine that the predicate is always false.
6157 On the next round of propagation, i_13 is determined to be
6158 VARYING, which causes i_5 to drop down to VARYING. So, another
6159 visit to i_14 is scheduled. In this second visit, we compute the
6160 exact same range and equivalence set for i_14, namely ~[0, 0] and
6161 { i_5 }. But we did not have the previous range for i_5
6162 registered, so vrp_visit_assignment thinks that the range for
6163 i_14 has not changed. Therefore, the predicate 'if (i_14 == 1)'
6164 is not visited again, which stops propagation from visiting
6165 statements in the THEN clause of that if().
6167 To properly fix this we would need to keep the previous range
6168 value for the names in the equivalence set. This way we would've
6169 discovered that from one visit to the other i_5 changed from
6170 range [8, 8] to VR_VARYING.
6172 However, fixing this apparent limitation may not be worth the
6173 additional checking. Testing on several code bases (GCC, DLV,
6174 MICO, TRAMP3D and SPEC2000) showed that doing this results in
6175 4 more predicates folded in SPEC. */
6178 val = vrp_evaluate_conditional_warnv_with_ops (gimple_cond_code (stmt),
6179 gimple_cond_lhs (stmt),
6180 gimple_cond_rhs (stmt),
6185 *taken_edge_p = find_taken_edge (gimple_bb (stmt), val);
6188 if (dump_file && (dump_flags & TDF_DETAILS))
6190 "\nIgnoring predicate evaluation because "
6191 "it assumes that signed overflow is undefined");
6196 if (dump_file && (dump_flags & TDF_DETAILS))
6198 fprintf (dump_file, "\nPredicate evaluates to: ");
6199 if (val == NULL_TREE)
6200 fprintf (dump_file, "DON'T KNOW\n");
6202 print_generic_stmt (dump_file, val, 0);
6205 return (*taken_edge_p) ? SSA_PROP_INTERESTING : SSA_PROP_VARYING;
6208 /* Searches the case label vector VEC for the index *IDX of the CASE_LABEL
6209 that includes the value VAL. The search is restricted to the range
6210 [START_IDX, n - 1] where n is the size of VEC.
6212 If there is a CASE_LABEL for VAL, its index is placed in IDX and true is
6215 If there is no CASE_LABEL for VAL and there is one that is larger than VAL,
6216 it is placed in IDX and false is returned.
6218 If VAL is larger than any CASE_LABEL, n is placed on IDX and false is
6222 find_case_label_index (gimple stmt, size_t start_idx, tree val, size_t *idx)
6224 size_t n = gimple_switch_num_labels (stmt);
6227 /* Find case label for minimum of the value range or the next one.
6228 At each iteration we are searching in [low, high - 1]. */
6230 for (low = start_idx, high = n; high != low; )
6234 /* Note that i != high, so we never ask for n. */
6235 size_t i = (high + low) / 2;
6236 t = gimple_switch_label (stmt, i);
6238 /* Cache the result of comparing CASE_LOW and val. */
6239 cmp = tree_int_cst_compare (CASE_LOW (t), val);
6243 /* Ranges cannot be empty. */
6252 if (CASE_HIGH (t) != NULL
6253 && tree_int_cst_compare (CASE_HIGH (t), val) >= 0)
6265 /* Searches the case label vector VEC for the range of CASE_LABELs that is used
6266 for values between MIN and MAX. The first index is placed in MIN_IDX. The
6267 last index is placed in MAX_IDX. If the range of CASE_LABELs is empty
6268 then MAX_IDX < MIN_IDX.
6269 Returns true if the default label is not needed. */
6272 find_case_label_range (gimple stmt, tree min, tree max, size_t *min_idx,
6276 bool min_take_default = !find_case_label_index (stmt, 1, min, &i);
6277 bool max_take_default = !find_case_label_index (stmt, i, max, &j);
6281 && max_take_default)
6283 /* Only the default case label reached.
6284 Return an empty range. */
6291 bool take_default = min_take_default || max_take_default;
6295 if (max_take_default)
6298 /* If the case label range is continuous, we do not need
6299 the default case label. Verify that. */
6300 high = CASE_LOW (gimple_switch_label (stmt, i));
6301 if (CASE_HIGH (gimple_switch_label (stmt, i)))
6302 high = CASE_HIGH (gimple_switch_label (stmt, i));
6303 for (k = i + 1; k <= j; ++k)
6305 low = CASE_LOW (gimple_switch_label (stmt, k));
6306 if (!integer_onep (int_const_binop (MINUS_EXPR, low, high)))
6308 take_default = true;
6312 if (CASE_HIGH (gimple_switch_label (stmt, k)))
6313 high = CASE_HIGH (gimple_switch_label (stmt, k));
6318 return !take_default;
6322 /* Visit switch statement STMT. If we can determine which edge
6323 will be taken out of STMT's basic block, record it in
6324 *TAKEN_EDGE_P and return SSA_PROP_INTERESTING. Otherwise, return
6325 SSA_PROP_VARYING. */
6327 static enum ssa_prop_result
6328 vrp_visit_switch_stmt (gimple stmt, edge *taken_edge_p)
6332 size_t i = 0, j = 0;
6335 *taken_edge_p = NULL;
6336 op = gimple_switch_index (stmt);
6337 if (TREE_CODE (op) != SSA_NAME)
6338 return SSA_PROP_VARYING;
6340 vr = get_value_range (op);
6341 if (dump_file && (dump_flags & TDF_DETAILS))
6343 fprintf (dump_file, "\nVisiting switch expression with operand ");
6344 print_generic_expr (dump_file, op, 0);
6345 fprintf (dump_file, " with known range ");
6346 dump_value_range (dump_file, vr);
6347 fprintf (dump_file, "\n");
6350 if (vr->type != VR_RANGE
6351 || symbolic_range_p (vr))
6352 return SSA_PROP_VARYING;
6354 /* Find the single edge that is taken from the switch expression. */
6355 take_default = !find_case_label_range (stmt, vr->min, vr->max, &i, &j);
6357 /* Check if the range spans no CASE_LABEL. If so, we only reach the default
6361 gcc_assert (take_default);
6362 val = gimple_switch_default_label (stmt);
6366 /* Check if labels with index i to j and maybe the default label
6367 are all reaching the same label. */
6369 val = gimple_switch_label (stmt, i);
6371 && CASE_LABEL (gimple_switch_default_label (stmt))
6372 != CASE_LABEL (val))
6374 if (dump_file && (dump_flags & TDF_DETAILS))
6375 fprintf (dump_file, " not a single destination for this "
6377 return SSA_PROP_VARYING;
6379 for (++i; i <= j; ++i)
6381 if (CASE_LABEL (gimple_switch_label (stmt, i)) != CASE_LABEL (val))
6383 if (dump_file && (dump_flags & TDF_DETAILS))
6384 fprintf (dump_file, " not a single destination for this "
6386 return SSA_PROP_VARYING;
6391 *taken_edge_p = find_edge (gimple_bb (stmt),
6392 label_to_block (CASE_LABEL (val)));
6394 if (dump_file && (dump_flags & TDF_DETAILS))
6396 fprintf (dump_file, " will take edge to ");
6397 print_generic_stmt (dump_file, CASE_LABEL (val), 0);
6400 return SSA_PROP_INTERESTING;
6404 /* Evaluate statement STMT. If the statement produces a useful range,
6405 return SSA_PROP_INTERESTING and record the SSA name with the
6406 interesting range into *OUTPUT_P.
6408 If STMT is a conditional branch and we can determine its truth
6409 value, the taken edge is recorded in *TAKEN_EDGE_P.
6411 If STMT produces a varying value, return SSA_PROP_VARYING. */
6413 static enum ssa_prop_result
6414 vrp_visit_stmt (gimple stmt, edge *taken_edge_p, tree *output_p)
6419 if (dump_file && (dump_flags & TDF_DETAILS))
6421 fprintf (dump_file, "\nVisiting statement:\n");
6422 print_gimple_stmt (dump_file, stmt, 0, dump_flags);
6423 fprintf (dump_file, "\n");
6426 if (!stmt_interesting_for_vrp (stmt))
6427 gcc_assert (stmt_ends_bb_p (stmt));
6428 else if (is_gimple_assign (stmt) || is_gimple_call (stmt))
6430 /* In general, assignments with virtual operands are not useful
6431 for deriving ranges, with the obvious exception of calls to
6432 builtin functions. */
6433 if ((is_gimple_call (stmt)
6434 && gimple_call_fndecl (stmt) != NULL_TREE
6435 && DECL_IS_BUILTIN (gimple_call_fndecl (stmt)))
6436 || !gimple_vuse (stmt))
6437 return vrp_visit_assignment_or_call (stmt, output_p);
6439 else if (gimple_code (stmt) == GIMPLE_COND)
6440 return vrp_visit_cond_stmt (stmt, taken_edge_p);
6441 else if (gimple_code (stmt) == GIMPLE_SWITCH)
6442 return vrp_visit_switch_stmt (stmt, taken_edge_p);
6444 /* All other statements produce nothing of interest for VRP, so mark
6445 their outputs varying and prevent further simulation. */
6446 FOR_EACH_SSA_TREE_OPERAND (def, stmt, iter, SSA_OP_DEF)
6447 set_value_range_to_varying (get_value_range (def));
6449 return SSA_PROP_VARYING;
6453 /* Meet operation for value ranges. Given two value ranges VR0 and
6454 VR1, store in VR0 a range that contains both VR0 and VR1. This
6455 may not be the smallest possible such range. */
6458 vrp_meet (value_range_t *vr0, value_range_t *vr1)
6460 if (vr0->type == VR_UNDEFINED)
6462 copy_value_range (vr0, vr1);
6466 if (vr1->type == VR_UNDEFINED)
6468 /* Nothing to do. VR0 already has the resulting range. */
6472 if (vr0->type == VR_VARYING)
6474 /* Nothing to do. VR0 already has the resulting range. */
6478 if (vr1->type == VR_VARYING)
6480 set_value_range_to_varying (vr0);
6484 if (vr0->type == VR_RANGE && vr1->type == VR_RANGE)
6489 /* Compute the convex hull of the ranges. The lower limit of
6490 the new range is the minimum of the two ranges. If they
6491 cannot be compared, then give up. */
6492 cmp = compare_values (vr0->min, vr1->min);
6493 if (cmp == 0 || cmp == 1)
6500 /* Similarly, the upper limit of the new range is the maximum
6501 of the two ranges. If they cannot be compared, then
6503 cmp = compare_values (vr0->max, vr1->max);
6504 if (cmp == 0 || cmp == -1)
6511 /* Check for useless ranges. */
6512 if (INTEGRAL_TYPE_P (TREE_TYPE (min))
6513 && ((vrp_val_is_min (min) || is_overflow_infinity (min))
6514 && (vrp_val_is_max (max) || is_overflow_infinity (max))))
6517 /* The resulting set of equivalences is the intersection of
6519 if (vr0->equiv && vr1->equiv && vr0->equiv != vr1->equiv)
6520 bitmap_and_into (vr0->equiv, vr1->equiv);
6521 else if (vr0->equiv && !vr1->equiv)
6522 bitmap_clear (vr0->equiv);
6524 set_value_range (vr0, vr0->type, min, max, vr0->equiv);
6526 else if (vr0->type == VR_ANTI_RANGE && vr1->type == VR_ANTI_RANGE)
6528 /* Two anti-ranges meet only if their complements intersect.
6529 Only handle the case of identical ranges. */
6530 if (compare_values (vr0->min, vr1->min) == 0
6531 && compare_values (vr0->max, vr1->max) == 0
6532 && compare_values (vr0->min, vr0->max) == 0)
6534 /* The resulting set of equivalences is the intersection of
6536 if (vr0->equiv && vr1->equiv && vr0->equiv != vr1->equiv)
6537 bitmap_and_into (vr0->equiv, vr1->equiv);
6538 else if (vr0->equiv && !vr1->equiv)
6539 bitmap_clear (vr0->equiv);
6544 else if (vr0->type == VR_ANTI_RANGE || vr1->type == VR_ANTI_RANGE)
6546 /* For a numeric range [VAL1, VAL2] and an anti-range ~[VAL3, VAL4],
6547 only handle the case where the ranges have an empty intersection.
6548 The result of the meet operation is the anti-range. */
6549 if (!symbolic_range_p (vr0)
6550 && !symbolic_range_p (vr1)
6551 && !value_ranges_intersect_p (vr0, vr1))
6553 /* Copy most of VR1 into VR0. Don't copy VR1's equivalence
6554 set. We need to compute the intersection of the two
6555 equivalence sets. */
6556 if (vr1->type == VR_ANTI_RANGE)
6557 set_value_range (vr0, vr1->type, vr1->min, vr1->max, vr0->equiv);
6559 /* The resulting set of equivalences is the intersection of
6561 if (vr0->equiv && vr1->equiv && vr0->equiv != vr1->equiv)
6562 bitmap_and_into (vr0->equiv, vr1->equiv);
6563 else if (vr0->equiv && !vr1->equiv)
6564 bitmap_clear (vr0->equiv);
6575 /* Failed to find an efficient meet. Before giving up and setting
6576 the result to VARYING, see if we can at least derive a useful
6577 anti-range. FIXME, all this nonsense about distinguishing
6578 anti-ranges from ranges is necessary because of the odd
6579 semantics of range_includes_zero_p and friends. */
6580 if (!symbolic_range_p (vr0)
6581 && ((vr0->type == VR_RANGE && !range_includes_zero_p (vr0))
6582 || (vr0->type == VR_ANTI_RANGE && range_includes_zero_p (vr0)))
6583 && !symbolic_range_p (vr1)
6584 && ((vr1->type == VR_RANGE && !range_includes_zero_p (vr1))
6585 || (vr1->type == VR_ANTI_RANGE && range_includes_zero_p (vr1))))
6587 set_value_range_to_nonnull (vr0, TREE_TYPE (vr0->min));
6589 /* Since this meet operation did not result from the meeting of
6590 two equivalent names, VR0 cannot have any equivalences. */
6592 bitmap_clear (vr0->equiv);
6595 set_value_range_to_varying (vr0);
6599 /* Visit all arguments for PHI node PHI that flow through executable
6600 edges. If a valid value range can be derived from all the incoming
6601 value ranges, set a new range for the LHS of PHI. */
6603 static enum ssa_prop_result
6604 vrp_visit_phi_node (gimple phi)
6607 tree lhs = PHI_RESULT (phi);
6608 value_range_t *lhs_vr = get_value_range (lhs);
6609 value_range_t vr_result = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
6610 int edges, old_edges;
6613 if (dump_file && (dump_flags & TDF_DETAILS))
6615 fprintf (dump_file, "\nVisiting PHI node: ");
6616 print_gimple_stmt (dump_file, phi, 0, dump_flags);
6620 for (i = 0; i < gimple_phi_num_args (phi); i++)
6622 edge e = gimple_phi_arg_edge (phi, i);
6624 if (dump_file && (dump_flags & TDF_DETAILS))
6627 "\n Argument #%d (%d -> %d %sexecutable)\n",
6628 (int) i, e->src->index, e->dest->index,
6629 (e->flags & EDGE_EXECUTABLE) ? "" : "not ");
6632 if (e->flags & EDGE_EXECUTABLE)
6634 tree arg = PHI_ARG_DEF (phi, i);
6635 value_range_t vr_arg;
6639 if (TREE_CODE (arg) == SSA_NAME)
6641 vr_arg = *(get_value_range (arg));
6645 if (is_overflow_infinity (arg))
6647 arg = copy_node (arg);
6648 TREE_OVERFLOW (arg) = 0;
6651 vr_arg.type = VR_RANGE;
6654 vr_arg.equiv = NULL;
6657 if (dump_file && (dump_flags & TDF_DETAILS))
6659 fprintf (dump_file, "\t");
6660 print_generic_expr (dump_file, arg, dump_flags);
6661 fprintf (dump_file, "\n\tValue: ");
6662 dump_value_range (dump_file, &vr_arg);
6663 fprintf (dump_file, "\n");
6666 vrp_meet (&vr_result, &vr_arg);
6668 if (vr_result.type == VR_VARYING)
6673 if (vr_result.type == VR_VARYING)
6675 else if (vr_result.type == VR_UNDEFINED)
6678 old_edges = vr_phi_edge_counts[SSA_NAME_VERSION (lhs)];
6679 vr_phi_edge_counts[SSA_NAME_VERSION (lhs)] = edges;
6681 /* To prevent infinite iterations in the algorithm, derive ranges
6682 when the new value is slightly bigger or smaller than the
6683 previous one. We don't do this if we have seen a new executable
6684 edge; this helps us avoid an overflow infinity for conditionals
6685 which are not in a loop. */
6687 && gimple_phi_num_args (phi) > 1
6688 && edges == old_edges)
6690 int cmp_min = compare_values (lhs_vr->min, vr_result.min);
6691 int cmp_max = compare_values (lhs_vr->max, vr_result.max);
6693 /* For non VR_RANGE or for pointers fall back to varying if
6694 the range changed. */
6695 if ((lhs_vr->type != VR_RANGE || vr_result.type != VR_RANGE
6696 || POINTER_TYPE_P (TREE_TYPE (lhs)))
6697 && (cmp_min != 0 || cmp_max != 0))
6700 /* If the new minimum is smaller or larger than the previous
6701 one, go all the way to -INF. In the first case, to avoid
6702 iterating millions of times to reach -INF, and in the
6703 other case to avoid infinite bouncing between different
6705 if (cmp_min > 0 || cmp_min < 0)
6707 if (!needs_overflow_infinity (TREE_TYPE (vr_result.min))
6708 || !vrp_var_may_overflow (lhs, phi))
6709 vr_result.min = TYPE_MIN_VALUE (TREE_TYPE (vr_result.min));
6710 else if (supports_overflow_infinity (TREE_TYPE (vr_result.min)))
6712 negative_overflow_infinity (TREE_TYPE (vr_result.min));
6715 /* Similarly, if the new maximum is smaller or larger than
6716 the previous one, go all the way to +INF. */
6717 if (cmp_max < 0 || cmp_max > 0)
6719 if (!needs_overflow_infinity (TREE_TYPE (vr_result.max))
6720 || !vrp_var_may_overflow (lhs, phi))
6721 vr_result.max = TYPE_MAX_VALUE (TREE_TYPE (vr_result.max));
6722 else if (supports_overflow_infinity (TREE_TYPE (vr_result.max)))
6724 positive_overflow_infinity (TREE_TYPE (vr_result.max));
6727 /* If we dropped either bound to +-INF then if this is a loop
6728 PHI node SCEV may known more about its value-range. */
6729 if ((cmp_min > 0 || cmp_min < 0
6730 || cmp_max < 0 || cmp_max > 0)
6732 && (l = loop_containing_stmt (phi))
6733 && l->header == gimple_bb (phi))
6734 adjust_range_with_scev (&vr_result, l, phi, lhs);
6736 /* If we will end up with a (-INF, +INF) range, set it to
6737 VARYING. Same if the previous max value was invalid for
6738 the type and we end up with vr_result.min > vr_result.max. */
6739 if ((vrp_val_is_max (vr_result.max)
6740 && vrp_val_is_min (vr_result.min))
6741 || compare_values (vr_result.min,
6746 /* If the new range is different than the previous value, keep
6749 if (update_value_range (lhs, &vr_result))
6751 if (dump_file && (dump_flags & TDF_DETAILS))
6753 fprintf (dump_file, "Found new range for ");
6754 print_generic_expr (dump_file, lhs, 0);
6755 fprintf (dump_file, ": ");
6756 dump_value_range (dump_file, &vr_result);
6757 fprintf (dump_file, "\n\n");
6760 return SSA_PROP_INTERESTING;
6763 /* Nothing changed, don't add outgoing edges. */
6764 return SSA_PROP_NOT_INTERESTING;
6766 /* No match found. Set the LHS to VARYING. */
6768 set_value_range_to_varying (lhs_vr);
6769 return SSA_PROP_VARYING;
6772 /* Simplify boolean operations if the source is known
6773 to be already a boolean. */
6775 simplify_truth_ops_using_ranges (gimple_stmt_iterator *gsi, gimple stmt)
6777 enum tree_code rhs_code = gimple_assign_rhs_code (stmt);
6779 bool need_conversion;
6781 /* We handle only !=/== case here. */
6782 gcc_assert (rhs_code == EQ_EXPR || rhs_code == NE_EXPR);
6784 op0 = gimple_assign_rhs1 (stmt);
6785 if (!op_with_boolean_value_range_p (op0))
6788 op1 = gimple_assign_rhs2 (stmt);
6789 if (!op_with_boolean_value_range_p (op1))
6792 /* Reduce number of cases to handle to NE_EXPR. As there is no
6793 BIT_XNOR_EXPR we cannot replace A == B with a single statement. */
6794 if (rhs_code == EQ_EXPR)
6796 if (TREE_CODE (op1) == INTEGER_CST)
6797 op1 = int_const_binop (BIT_XOR_EXPR, op1, integer_one_node);
6802 lhs = gimple_assign_lhs (stmt);
6804 = !useless_type_conversion_p (TREE_TYPE (lhs), TREE_TYPE (op0));
6806 /* Make sure to not sign-extend a 1-bit 1 when converting the result. */
6808 && !TYPE_UNSIGNED (TREE_TYPE (op0))
6809 && TYPE_PRECISION (TREE_TYPE (op0)) == 1
6810 && TYPE_PRECISION (TREE_TYPE (lhs)) > 1)
6813 /* For A != 0 we can substitute A itself. */
6814 if (integer_zerop (op1))
6815 gimple_assign_set_rhs_with_ops (gsi,
6817 ? NOP_EXPR : TREE_CODE (op0),
6819 /* For A != B we substitute A ^ B. Either with conversion. */
6820 else if (need_conversion)
6823 tree tem = create_tmp_reg (TREE_TYPE (op0), NULL);
6824 newop = gimple_build_assign_with_ops (BIT_XOR_EXPR, tem, op0, op1);
6825 tem = make_ssa_name (tem, newop);
6826 gimple_assign_set_lhs (newop, tem);
6827 gsi_insert_before (gsi, newop, GSI_SAME_STMT);
6828 update_stmt (newop);
6829 gimple_assign_set_rhs_with_ops (gsi, NOP_EXPR, tem, NULL_TREE);
6833 gimple_assign_set_rhs_with_ops (gsi, BIT_XOR_EXPR, op0, op1);
6834 update_stmt (gsi_stmt (*gsi));
6839 /* Simplify a division or modulo operator to a right shift or
6840 bitwise and if the first operand is unsigned or is greater
6841 than zero and the second operand is an exact power of two. */
6844 simplify_div_or_mod_using_ranges (gimple stmt)
6846 enum tree_code rhs_code = gimple_assign_rhs_code (stmt);
6848 tree op0 = gimple_assign_rhs1 (stmt);
6849 tree op1 = gimple_assign_rhs2 (stmt);
6850 value_range_t *vr = get_value_range (gimple_assign_rhs1 (stmt));
6852 if (TYPE_UNSIGNED (TREE_TYPE (op0)))
6854 val = integer_one_node;
6860 val = compare_range_with_value (GE_EXPR, vr, integer_zero_node, &sop);
6864 && integer_onep (val)
6865 && issue_strict_overflow_warning (WARN_STRICT_OVERFLOW_MISC))
6867 location_t location;
6869 if (!gimple_has_location (stmt))
6870 location = input_location;
6872 location = gimple_location (stmt);
6873 warning_at (location, OPT_Wstrict_overflow,
6874 "assuming signed overflow does not occur when "
6875 "simplifying %</%> or %<%%%> to %<>>%> or %<&%>");
6879 if (val && integer_onep (val))
6883 if (rhs_code == TRUNC_DIV_EXPR)
6885 t = build_int_cst (integer_type_node, tree_log2 (op1));
6886 gimple_assign_set_rhs_code (stmt, RSHIFT_EXPR);
6887 gimple_assign_set_rhs1 (stmt, op0);
6888 gimple_assign_set_rhs2 (stmt, t);
6892 t = build_int_cst (TREE_TYPE (op1), 1);
6893 t = int_const_binop (MINUS_EXPR, op1, t);
6894 t = fold_convert (TREE_TYPE (op0), t);
6896 gimple_assign_set_rhs_code (stmt, BIT_AND_EXPR);
6897 gimple_assign_set_rhs1 (stmt, op0);
6898 gimple_assign_set_rhs2 (stmt, t);
6908 /* If the operand to an ABS_EXPR is >= 0, then eliminate the
6909 ABS_EXPR. If the operand is <= 0, then simplify the
6910 ABS_EXPR into a NEGATE_EXPR. */
6913 simplify_abs_using_ranges (gimple stmt)
6916 tree op = gimple_assign_rhs1 (stmt);
6917 tree type = TREE_TYPE (op);
6918 value_range_t *vr = get_value_range (op);
6920 if (TYPE_UNSIGNED (type))
6922 val = integer_zero_node;
6928 val = compare_range_with_value (LE_EXPR, vr, integer_zero_node, &sop);
6932 val = compare_range_with_value (GE_EXPR, vr, integer_zero_node,
6937 if (integer_zerop (val))
6938 val = integer_one_node;
6939 else if (integer_onep (val))
6940 val = integer_zero_node;
6945 && (integer_onep (val) || integer_zerop (val)))
6947 if (sop && issue_strict_overflow_warning (WARN_STRICT_OVERFLOW_MISC))
6949 location_t location;
6951 if (!gimple_has_location (stmt))
6952 location = input_location;
6954 location = gimple_location (stmt);
6955 warning_at (location, OPT_Wstrict_overflow,
6956 "assuming signed overflow does not occur when "
6957 "simplifying %<abs (X)%> to %<X%> or %<-X%>");
6960 gimple_assign_set_rhs1 (stmt, op);
6961 if (integer_onep (val))
6962 gimple_assign_set_rhs_code (stmt, NEGATE_EXPR);
6964 gimple_assign_set_rhs_code (stmt, SSA_NAME);
6973 /* Optimize away redundant BIT_AND_EXPR and BIT_IOR_EXPR.
6974 If all the bits that are being cleared by & are already
6975 known to be zero from VR, or all the bits that are being
6976 set by | are already known to be one from VR, the bit
6977 operation is redundant. */
6980 simplify_bit_ops_using_ranges (gimple_stmt_iterator *gsi, gimple stmt)
6982 tree op0 = gimple_assign_rhs1 (stmt);
6983 tree op1 = gimple_assign_rhs2 (stmt);
6984 tree op = NULL_TREE;
6985 value_range_t vr0 = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
6986 value_range_t vr1 = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
6987 double_int may_be_nonzero0, may_be_nonzero1;
6988 double_int must_be_nonzero0, must_be_nonzero1;
6991 if (TREE_CODE (op0) == SSA_NAME)
6992 vr0 = *(get_value_range (op0));
6993 else if (is_gimple_min_invariant (op0))
6994 set_value_range_to_value (&vr0, op0, NULL);
6998 if (TREE_CODE (op1) == SSA_NAME)
6999 vr1 = *(get_value_range (op1));
7000 else if (is_gimple_min_invariant (op1))
7001 set_value_range_to_value (&vr1, op1, NULL);
7005 if (!zero_nonzero_bits_from_vr (&vr0, &may_be_nonzero0, &must_be_nonzero0))
7007 if (!zero_nonzero_bits_from_vr (&vr1, &may_be_nonzero1, &must_be_nonzero1))
7010 switch (gimple_assign_rhs_code (stmt))
7013 mask = double_int_and_not (may_be_nonzero0, must_be_nonzero1);
7014 if (double_int_zero_p (mask))
7019 mask = double_int_and_not (may_be_nonzero1, must_be_nonzero0);
7020 if (double_int_zero_p (mask))
7027 mask = double_int_and_not (may_be_nonzero0, must_be_nonzero1);
7028 if (double_int_zero_p (mask))
7033 mask = double_int_and_not (may_be_nonzero1, must_be_nonzero0);
7034 if (double_int_zero_p (mask))
7044 if (op == NULL_TREE)
7047 gimple_assign_set_rhs_with_ops (gsi, TREE_CODE (op), op, NULL);
7048 update_stmt (gsi_stmt (*gsi));
7052 /* We are comparing trees OP0 and OP1 using COND_CODE. OP0 has
7053 a known value range VR.
7055 If there is one and only one value which will satisfy the
7056 conditional, then return that value. Else return NULL. */
7059 test_for_singularity (enum tree_code cond_code, tree op0,
7060 tree op1, value_range_t *vr)
7065 /* Extract minimum/maximum values which satisfy the
7066 the conditional as it was written. */
7067 if (cond_code == LE_EXPR || cond_code == LT_EXPR)
7069 /* This should not be negative infinity; there is no overflow
7071 min = TYPE_MIN_VALUE (TREE_TYPE (op0));
7074 if (cond_code == LT_EXPR && !is_overflow_infinity (max))
7076 tree one = build_int_cst (TREE_TYPE (op0), 1);
7077 max = fold_build2 (MINUS_EXPR, TREE_TYPE (op0), max, one);
7079 TREE_NO_WARNING (max) = 1;
7082 else if (cond_code == GE_EXPR || cond_code == GT_EXPR)
7084 /* This should not be positive infinity; there is no overflow
7086 max = TYPE_MAX_VALUE (TREE_TYPE (op0));
7089 if (cond_code == GT_EXPR && !is_overflow_infinity (min))
7091 tree one = build_int_cst (TREE_TYPE (op0), 1);
7092 min = fold_build2 (PLUS_EXPR, TREE_TYPE (op0), min, one);
7094 TREE_NO_WARNING (min) = 1;
7098 /* Now refine the minimum and maximum values using any
7099 value range information we have for op0. */
7102 if (compare_values (vr->min, min) == 1)
7104 if (compare_values (vr->max, max) == -1)
7107 /* If the new min/max values have converged to a single value,
7108 then there is only one value which can satisfy the condition,
7109 return that value. */
7110 if (operand_equal_p (min, max, 0) && is_gimple_min_invariant (min))
7116 /* Simplify a conditional using a relational operator to an equality
7117 test if the range information indicates only one value can satisfy
7118 the original conditional. */
7121 simplify_cond_using_ranges (gimple stmt)
7123 tree op0 = gimple_cond_lhs (stmt);
7124 tree op1 = gimple_cond_rhs (stmt);
7125 enum tree_code cond_code = gimple_cond_code (stmt);
7127 if (cond_code != NE_EXPR
7128 && cond_code != EQ_EXPR
7129 && TREE_CODE (op0) == SSA_NAME
7130 && INTEGRAL_TYPE_P (TREE_TYPE (op0))
7131 && is_gimple_min_invariant (op1))
7133 value_range_t *vr = get_value_range (op0);
7135 /* If we have range information for OP0, then we might be
7136 able to simplify this conditional. */
7137 if (vr->type == VR_RANGE)
7139 tree new_tree = test_for_singularity (cond_code, op0, op1, vr);
7145 fprintf (dump_file, "Simplified relational ");
7146 print_gimple_stmt (dump_file, stmt, 0, 0);
7147 fprintf (dump_file, " into ");
7150 gimple_cond_set_code (stmt, EQ_EXPR);
7151 gimple_cond_set_lhs (stmt, op0);
7152 gimple_cond_set_rhs (stmt, new_tree);
7158 print_gimple_stmt (dump_file, stmt, 0, 0);
7159 fprintf (dump_file, "\n");
7165 /* Try again after inverting the condition. We only deal
7166 with integral types here, so no need to worry about
7167 issues with inverting FP comparisons. */
7168 cond_code = invert_tree_comparison (cond_code, false);
7169 new_tree = test_for_singularity (cond_code, op0, op1, vr);
7175 fprintf (dump_file, "Simplified relational ");
7176 print_gimple_stmt (dump_file, stmt, 0, 0);
7177 fprintf (dump_file, " into ");
7180 gimple_cond_set_code (stmt, NE_EXPR);
7181 gimple_cond_set_lhs (stmt, op0);
7182 gimple_cond_set_rhs (stmt, new_tree);
7188 print_gimple_stmt (dump_file, stmt, 0, 0);
7189 fprintf (dump_file, "\n");
7200 /* Simplify a switch statement using the value range of the switch
7204 simplify_switch_using_ranges (gimple stmt)
7206 tree op = gimple_switch_index (stmt);
7211 size_t i = 0, j = 0, n, n2;
7215 if (TREE_CODE (op) == SSA_NAME)
7217 vr = get_value_range (op);
7219 /* We can only handle integer ranges. */
7220 if (vr->type != VR_RANGE
7221 || symbolic_range_p (vr))
7224 /* Find case label for min/max of the value range. */
7225 take_default = !find_case_label_range (stmt, vr->min, vr->max, &i, &j);
7227 else if (TREE_CODE (op) == INTEGER_CST)
7229 take_default = !find_case_label_index (stmt, 1, op, &i);
7243 n = gimple_switch_num_labels (stmt);
7245 /* Bail out if this is just all edges taken. */
7251 /* Build a new vector of taken case labels. */
7252 vec2 = make_tree_vec (j - i + 1 + (int)take_default);
7255 /* Add the default edge, if necessary. */
7257 TREE_VEC_ELT (vec2, n2++) = gimple_switch_default_label (stmt);
7259 for (; i <= j; ++i, ++n2)
7260 TREE_VEC_ELT (vec2, n2) = gimple_switch_label (stmt, i);
7262 /* Mark needed edges. */
7263 for (i = 0; i < n2; ++i)
7265 e = find_edge (gimple_bb (stmt),
7266 label_to_block (CASE_LABEL (TREE_VEC_ELT (vec2, i))));
7267 e->aux = (void *)-1;
7270 /* Queue not needed edges for later removal. */
7271 FOR_EACH_EDGE (e, ei, gimple_bb (stmt)->succs)
7273 if (e->aux == (void *)-1)
7279 if (dump_file && (dump_flags & TDF_DETAILS))
7281 fprintf (dump_file, "removing unreachable case label\n");
7283 VEC_safe_push (edge, heap, to_remove_edges, e);
7284 e->flags &= ~EDGE_EXECUTABLE;
7287 /* And queue an update for the stmt. */
7290 VEC_safe_push (switch_update, heap, to_update_switch_stmts, &su);
7294 /* Simplify an integral conversion from an SSA name in STMT. */
7297 simplify_conversion_using_ranges (gimple stmt)
7299 tree innerop, middleop, finaltype;
7301 value_range_t *innervr;
7302 double_int innermin, innermax, middlemin, middlemax;
7304 finaltype = TREE_TYPE (gimple_assign_lhs (stmt));
7305 if (!INTEGRAL_TYPE_P (finaltype))
7307 middleop = gimple_assign_rhs1 (stmt);
7308 def_stmt = SSA_NAME_DEF_STMT (middleop);
7309 if (!is_gimple_assign (def_stmt)
7310 || !CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (def_stmt)))
7312 innerop = gimple_assign_rhs1 (def_stmt);
7313 if (TREE_CODE (innerop) != SSA_NAME)
7316 /* Get the value-range of the inner operand. */
7317 innervr = get_value_range (innerop);
7318 if (innervr->type != VR_RANGE
7319 || TREE_CODE (innervr->min) != INTEGER_CST
7320 || TREE_CODE (innervr->max) != INTEGER_CST)
7323 /* Simulate the conversion chain to check if the result is equal if
7324 the middle conversion is removed. */
7325 innermin = tree_to_double_int (innervr->min);
7326 innermax = tree_to_double_int (innervr->max);
7327 middlemin = double_int_ext (innermin, TYPE_PRECISION (TREE_TYPE (middleop)),
7328 TYPE_UNSIGNED (TREE_TYPE (middleop)));
7329 middlemax = double_int_ext (innermax, TYPE_PRECISION (TREE_TYPE (middleop)),
7330 TYPE_UNSIGNED (TREE_TYPE (middleop)));
7331 /* If the middle values do not represent a proper range fail. */
7332 if (double_int_cmp (middlemin, middlemax,
7333 TYPE_UNSIGNED (TREE_TYPE (middleop))) > 0)
7335 if (!double_int_equal_p (double_int_ext (middlemin,
7336 TYPE_PRECISION (finaltype),
7337 TYPE_UNSIGNED (finaltype)),
7338 double_int_ext (innermin,
7339 TYPE_PRECISION (finaltype),
7340 TYPE_UNSIGNED (finaltype)))
7341 || !double_int_equal_p (double_int_ext (middlemax,
7342 TYPE_PRECISION (finaltype),
7343 TYPE_UNSIGNED (finaltype)),
7344 double_int_ext (innermax,
7345 TYPE_PRECISION (finaltype),
7346 TYPE_UNSIGNED (finaltype))))
7349 gimple_assign_set_rhs1 (stmt, innerop);
7354 /* Return whether the value range *VR fits in an integer type specified
7355 by PRECISION and UNSIGNED_P. */
7358 range_fits_type_p (value_range_t *vr, unsigned precision, bool unsigned_p)
7361 unsigned src_precision;
7364 /* We can only handle integral and pointer types. */
7365 src_type = TREE_TYPE (vr->min);
7366 if (!INTEGRAL_TYPE_P (src_type)
7367 && !POINTER_TYPE_P (src_type))
7370 /* An extension is always fine, so is an identity transform. */
7371 src_precision = TYPE_PRECISION (TREE_TYPE (vr->min));
7372 if (src_precision < precision
7373 || (src_precision == precision
7374 && TYPE_UNSIGNED (src_type) == unsigned_p))
7377 /* Now we can only handle ranges with constant bounds. */
7378 if (vr->type != VR_RANGE
7379 || TREE_CODE (vr->min) != INTEGER_CST
7380 || TREE_CODE (vr->max) != INTEGER_CST)
7383 /* For precision-preserving sign-changes the MSB of the double-int
7385 if (src_precision == precision
7386 && (TREE_INT_CST_HIGH (vr->min) | TREE_INT_CST_HIGH (vr->max)) < 0)
7389 /* Then we can perform the conversion on both ends and compare
7390 the result for equality. */
7391 tem = double_int_ext (tree_to_double_int (vr->min), precision, unsigned_p);
7392 if (!double_int_equal_p (tree_to_double_int (vr->min), tem))
7394 tem = double_int_ext (tree_to_double_int (vr->max), precision, unsigned_p);
7395 if (!double_int_equal_p (tree_to_double_int (vr->max), tem))
7401 /* Simplify a conversion from integral SSA name to float in STMT. */
7404 simplify_float_conversion_using_ranges (gimple_stmt_iterator *gsi, gimple stmt)
7406 tree rhs1 = gimple_assign_rhs1 (stmt);
7407 value_range_t *vr = get_value_range (rhs1);
7408 enum machine_mode fltmode = TYPE_MODE (TREE_TYPE (gimple_assign_lhs (stmt)));
7409 enum machine_mode mode;
7413 /* We can only handle constant ranges. */
7414 if (vr->type != VR_RANGE
7415 || TREE_CODE (vr->min) != INTEGER_CST
7416 || TREE_CODE (vr->max) != INTEGER_CST)
7419 /* First check if we can use a signed type in place of an unsigned. */
7420 if (TYPE_UNSIGNED (TREE_TYPE (rhs1))
7421 && (can_float_p (fltmode, TYPE_MODE (TREE_TYPE (rhs1)), 0)
7422 != CODE_FOR_nothing)
7423 && range_fits_type_p (vr, GET_MODE_PRECISION
7424 (TYPE_MODE (TREE_TYPE (rhs1))), 0))
7425 mode = TYPE_MODE (TREE_TYPE (rhs1));
7426 /* If we can do the conversion in the current input mode do nothing. */
7427 else if (can_float_p (fltmode, TYPE_MODE (TREE_TYPE (rhs1)),
7428 TYPE_UNSIGNED (TREE_TYPE (rhs1))))
7430 /* Otherwise search for a mode we can use, starting from the narrowest
7431 integer mode available. */
7434 mode = GET_CLASS_NARROWEST_MODE (MODE_INT);
7437 /* If we cannot do a signed conversion to float from mode
7438 or if the value-range does not fit in the signed type
7439 try with a wider mode. */
7440 if (can_float_p (fltmode, mode, 0) != CODE_FOR_nothing
7441 && range_fits_type_p (vr, GET_MODE_PRECISION (mode), 0))
7444 mode = GET_MODE_WIDER_MODE (mode);
7445 /* But do not widen the input. Instead leave that to the
7446 optabs expansion code. */
7447 if (GET_MODE_PRECISION (mode) > TYPE_PRECISION (TREE_TYPE (rhs1)))
7450 while (mode != VOIDmode);
7451 if (mode == VOIDmode)
7455 /* It works, insert a truncation or sign-change before the
7456 float conversion. */
7457 tem = create_tmp_var (build_nonstandard_integer_type
7458 (GET_MODE_PRECISION (mode), 0), NULL);
7459 conv = gimple_build_assign_with_ops (NOP_EXPR, tem, rhs1, NULL_TREE);
7460 tem = make_ssa_name (tem, conv);
7461 gimple_assign_set_lhs (conv, tem);
7462 gsi_insert_before (gsi, conv, GSI_SAME_STMT);
7463 gimple_assign_set_rhs1 (stmt, tem);
7469 /* Simplify STMT using ranges if possible. */
7472 simplify_stmt_using_ranges (gimple_stmt_iterator *gsi)
7474 gimple stmt = gsi_stmt (*gsi);
7475 if (is_gimple_assign (stmt))
7477 enum tree_code rhs_code = gimple_assign_rhs_code (stmt);
7478 tree rhs1 = gimple_assign_rhs1 (stmt);
7484 /* Transform EQ_EXPR, NE_EXPR into BIT_XOR_EXPR or identity
7485 if the RHS is zero or one, and the LHS are known to be boolean
7487 if (INTEGRAL_TYPE_P (TREE_TYPE (rhs1)))
7488 return simplify_truth_ops_using_ranges (gsi, stmt);
7491 /* Transform TRUNC_DIV_EXPR and TRUNC_MOD_EXPR into RSHIFT_EXPR
7492 and BIT_AND_EXPR respectively if the first operand is greater
7493 than zero and the second operand is an exact power of two. */
7494 case TRUNC_DIV_EXPR:
7495 case TRUNC_MOD_EXPR:
7496 if (INTEGRAL_TYPE_P (TREE_TYPE (rhs1))
7497 && integer_pow2p (gimple_assign_rhs2 (stmt)))
7498 return simplify_div_or_mod_using_ranges (stmt);
7501 /* Transform ABS (X) into X or -X as appropriate. */
7503 if (TREE_CODE (rhs1) == SSA_NAME
7504 && INTEGRAL_TYPE_P (TREE_TYPE (rhs1)))
7505 return simplify_abs_using_ranges (stmt);
7510 /* Optimize away BIT_AND_EXPR and BIT_IOR_EXPR
7511 if all the bits being cleared are already cleared or
7512 all the bits being set are already set. */
7513 if (INTEGRAL_TYPE_P (TREE_TYPE (rhs1)))
7514 return simplify_bit_ops_using_ranges (gsi, stmt);
7518 if (TREE_CODE (rhs1) == SSA_NAME
7519 && INTEGRAL_TYPE_P (TREE_TYPE (rhs1)))
7520 return simplify_conversion_using_ranges (stmt);
7524 if (TREE_CODE (rhs1) == SSA_NAME
7525 && INTEGRAL_TYPE_P (TREE_TYPE (rhs1)))
7526 return simplify_float_conversion_using_ranges (gsi, stmt);
7533 else if (gimple_code (stmt) == GIMPLE_COND)
7534 return simplify_cond_using_ranges (stmt);
7535 else if (gimple_code (stmt) == GIMPLE_SWITCH)
7536 return simplify_switch_using_ranges (stmt);
7541 /* If the statement pointed by SI has a predicate whose value can be
7542 computed using the value range information computed by VRP, compute
7543 its value and return true. Otherwise, return false. */
7546 fold_predicate_in (gimple_stmt_iterator *si)
7548 bool assignment_p = false;
7550 gimple stmt = gsi_stmt (*si);
7552 if (is_gimple_assign (stmt)
7553 && TREE_CODE_CLASS (gimple_assign_rhs_code (stmt)) == tcc_comparison)
7555 assignment_p = true;
7556 val = vrp_evaluate_conditional (gimple_assign_rhs_code (stmt),
7557 gimple_assign_rhs1 (stmt),
7558 gimple_assign_rhs2 (stmt),
7561 else if (gimple_code (stmt) == GIMPLE_COND)
7562 val = vrp_evaluate_conditional (gimple_cond_code (stmt),
7563 gimple_cond_lhs (stmt),
7564 gimple_cond_rhs (stmt),
7572 val = fold_convert (gimple_expr_type (stmt), val);
7576 fprintf (dump_file, "Folding predicate ");
7577 print_gimple_expr (dump_file, stmt, 0, 0);
7578 fprintf (dump_file, " to ");
7579 print_generic_expr (dump_file, val, 0);
7580 fprintf (dump_file, "\n");
7583 if (is_gimple_assign (stmt))
7584 gimple_assign_set_rhs_from_tree (si, val);
7587 gcc_assert (gimple_code (stmt) == GIMPLE_COND);
7588 if (integer_zerop (val))
7589 gimple_cond_make_false (stmt);
7590 else if (integer_onep (val))
7591 gimple_cond_make_true (stmt);
7602 /* Callback for substitute_and_fold folding the stmt at *SI. */
7605 vrp_fold_stmt (gimple_stmt_iterator *si)
7607 if (fold_predicate_in (si))
7610 return simplify_stmt_using_ranges (si);
7613 /* Stack of dest,src equivalency pairs that need to be restored after
7614 each attempt to thread a block's incoming edge to an outgoing edge.
7616 A NULL entry is used to mark the end of pairs which need to be
7618 static VEC(tree,heap) *stack;
7620 /* A trivial wrapper so that we can present the generic jump threading
7621 code with a simple API for simplifying statements. STMT is the
7622 statement we want to simplify, WITHIN_STMT provides the location
7623 for any overflow warnings. */
7626 simplify_stmt_for_jump_threading (gimple stmt, gimple within_stmt)
7628 /* We only use VRP information to simplify conditionals. This is
7629 overly conservative, but it's unclear if doing more would be
7630 worth the compile time cost. */
7631 if (gimple_code (stmt) != GIMPLE_COND)
7634 return vrp_evaluate_conditional (gimple_cond_code (stmt),
7635 gimple_cond_lhs (stmt),
7636 gimple_cond_rhs (stmt), within_stmt);
7639 /* Blocks which have more than one predecessor and more than
7640 one successor present jump threading opportunities, i.e.,
7641 when the block is reached from a specific predecessor, we
7642 may be able to determine which of the outgoing edges will
7643 be traversed. When this optimization applies, we are able
7644 to avoid conditionals at runtime and we may expose secondary
7645 optimization opportunities.
7647 This routine is effectively a driver for the generic jump
7648 threading code. It basically just presents the generic code
7649 with edges that may be suitable for jump threading.
7651 Unlike DOM, we do not iterate VRP if jump threading was successful.
7652 While iterating may expose new opportunities for VRP, it is expected
7653 those opportunities would be very limited and the compile time cost
7654 to expose those opportunities would be significant.
7656 As jump threading opportunities are discovered, they are registered
7657 for later realization. */
7660 identify_jump_threads (void)
7667 /* Ugh. When substituting values earlier in this pass we can
7668 wipe the dominance information. So rebuild the dominator
7669 information as we need it within the jump threading code. */
7670 calculate_dominance_info (CDI_DOMINATORS);
7672 /* We do not allow VRP information to be used for jump threading
7673 across a back edge in the CFG. Otherwise it becomes too
7674 difficult to avoid eliminating loop exit tests. Of course
7675 EDGE_DFS_BACK is not accurate at this time so we have to
7677 mark_dfs_back_edges ();
7679 /* Do not thread across edges we are about to remove. Just marking
7680 them as EDGE_DFS_BACK will do. */
7681 FOR_EACH_VEC_ELT (edge, to_remove_edges, i, e)
7682 e->flags |= EDGE_DFS_BACK;
7684 /* Allocate our unwinder stack to unwind any temporary equivalences
7685 that might be recorded. */
7686 stack = VEC_alloc (tree, heap, 20);
7688 /* To avoid lots of silly node creation, we create a single
7689 conditional and just modify it in-place when attempting to
7691 dummy = gimple_build_cond (EQ_EXPR,
7692 integer_zero_node, integer_zero_node,
7695 /* Walk through all the blocks finding those which present a
7696 potential jump threading opportunity. We could set this up
7697 as a dominator walker and record data during the walk, but
7698 I doubt it's worth the effort for the classes of jump
7699 threading opportunities we are trying to identify at this
7700 point in compilation. */
7705 /* If the generic jump threading code does not find this block
7706 interesting, then there is nothing to do. */
7707 if (! potentially_threadable_block (bb))
7710 /* We only care about blocks ending in a COND_EXPR. While there
7711 may be some value in handling SWITCH_EXPR here, I doubt it's
7712 terribly important. */
7713 last = gsi_stmt (gsi_last_bb (bb));
7715 /* We're basically looking for a switch or any kind of conditional with
7716 integral or pointer type arguments. Note the type of the second
7717 argument will be the same as the first argument, so no need to
7718 check it explicitly. */
7719 if (gimple_code (last) == GIMPLE_SWITCH
7720 || (gimple_code (last) == GIMPLE_COND
7721 && TREE_CODE (gimple_cond_lhs (last)) == SSA_NAME
7722 && (INTEGRAL_TYPE_P (TREE_TYPE (gimple_cond_lhs (last)))
7723 || POINTER_TYPE_P (TREE_TYPE (gimple_cond_lhs (last))))
7724 && (TREE_CODE (gimple_cond_rhs (last)) == SSA_NAME
7725 || is_gimple_min_invariant (gimple_cond_rhs (last)))))
7729 /* We've got a block with multiple predecessors and multiple
7730 successors which also ends in a suitable conditional or
7731 switch statement. For each predecessor, see if we can thread
7732 it to a specific successor. */
7733 FOR_EACH_EDGE (e, ei, bb->preds)
7735 /* Do not thread across back edges or abnormal edges
7737 if (e->flags & (EDGE_DFS_BACK | EDGE_COMPLEX))
7740 thread_across_edge (dummy, e, true, &stack,
7741 simplify_stmt_for_jump_threading);
7746 /* We do not actually update the CFG or SSA graphs at this point as
7747 ASSERT_EXPRs are still in the IL and cfg cleanup code does not yet
7748 handle ASSERT_EXPRs gracefully. */
7751 /* We identified all the jump threading opportunities earlier, but could
7752 not transform the CFG at that time. This routine transforms the
7753 CFG and arranges for the dominator tree to be rebuilt if necessary.
7755 Note the SSA graph update will occur during the normal TODO
7756 processing by the pass manager. */
7758 finalize_jump_threads (void)
7760 thread_through_all_blocks (false);
7761 VEC_free (tree, heap, stack);
7765 /* Traverse all the blocks folding conditionals with known ranges. */
7772 values_propagated = true;
7776 fprintf (dump_file, "\nValue ranges after VRP:\n\n");
7777 dump_all_value_ranges (dump_file);
7778 fprintf (dump_file, "\n");
7781 substitute_and_fold (op_with_constant_singleton_value_range,
7782 vrp_fold_stmt, false);
7784 if (warn_array_bounds)
7785 check_all_array_refs ();
7787 /* We must identify jump threading opportunities before we release
7788 the datastructures built by VRP. */
7789 identify_jump_threads ();
7791 /* Free allocated memory. */
7792 for (i = 0; i < num_vr_values; i++)
7795 BITMAP_FREE (vr_value[i]->equiv);
7800 free (vr_phi_edge_counts);
7802 /* So that we can distinguish between VRP data being available
7803 and not available. */
7805 vr_phi_edge_counts = NULL;
7809 /* Main entry point to VRP (Value Range Propagation). This pass is
7810 loosely based on J. R. C. Patterson, ``Accurate Static Branch
7811 Prediction by Value Range Propagation,'' in SIGPLAN Conference on
7812 Programming Language Design and Implementation, pp. 67-78, 1995.
7813 Also available at http://citeseer.ist.psu.edu/patterson95accurate.html
7815 This is essentially an SSA-CCP pass modified to deal with ranges
7816 instead of constants.
7818 While propagating ranges, we may find that two or more SSA name
7819 have equivalent, though distinct ranges. For instance,
7822 2 p_4 = ASSERT_EXPR <p_3, p_3 != 0>
7824 4 p_5 = ASSERT_EXPR <p_4, p_4 == q_2>;
7828 In the code above, pointer p_5 has range [q_2, q_2], but from the
7829 code we can also determine that p_5 cannot be NULL and, if q_2 had
7830 a non-varying range, p_5's range should also be compatible with it.
7832 These equivalences are created by two expressions: ASSERT_EXPR and
7833 copy operations. Since p_5 is an assertion on p_4, and p_4 was the
7834 result of another assertion, then we can use the fact that p_5 and
7835 p_4 are equivalent when evaluating p_5's range.
7837 Together with value ranges, we also propagate these equivalences
7838 between names so that we can take advantage of information from
7839 multiple ranges when doing final replacement. Note that this
7840 equivalency relation is transitive but not symmetric.
7842 In the example above, p_5 is equivalent to p_4, q_2 and p_3, but we
7843 cannot assert that q_2 is equivalent to p_5 because q_2 may be used
7844 in contexts where that assertion does not hold (e.g., in line 6).
7846 TODO, the main difference between this pass and Patterson's is that
7847 we do not propagate edge probabilities. We only compute whether
7848 edges can be taken or not. That is, instead of having a spectrum
7849 of jump probabilities between 0 and 1, we only deal with 0, 1 and
7850 DON'T KNOW. In the future, it may be worthwhile to propagate
7851 probabilities to aid branch prediction. */
7860 loop_optimizer_init (LOOPS_NORMAL | LOOPS_HAVE_RECORDED_EXITS);
7861 rewrite_into_loop_closed_ssa (NULL, TODO_update_ssa);
7864 insert_range_assertions ();
7866 /* Estimate number of iterations - but do not use undefined behavior
7867 for this. We can't do this lazily as other functions may compute
7868 this using undefined behavior. */
7869 free_numbers_of_iterations_estimates ();
7870 estimate_numbers_of_iterations (false);
7872 to_remove_edges = VEC_alloc (edge, heap, 10);
7873 to_update_switch_stmts = VEC_alloc (switch_update, heap, 5);
7874 threadedge_initialize_values ();
7877 ssa_propagate (vrp_visit_stmt, vrp_visit_phi_node);
7880 free_numbers_of_iterations_estimates ();
7882 /* ASSERT_EXPRs must be removed before finalizing jump threads
7883 as finalizing jump threads calls the CFG cleanup code which
7884 does not properly handle ASSERT_EXPRs. */
7885 remove_range_assertions ();
7887 /* If we exposed any new variables, go ahead and put them into
7888 SSA form now, before we handle jump threading. This simplifies
7889 interactions between rewriting of _DECL nodes into SSA form
7890 and rewriting SSA_NAME nodes into SSA form after block
7891 duplication and CFG manipulation. */
7892 update_ssa (TODO_update_ssa);
7894 finalize_jump_threads ();
7896 /* Remove dead edges from SWITCH_EXPR optimization. This leaves the
7897 CFG in a broken state and requires a cfg_cleanup run. */
7898 FOR_EACH_VEC_ELT (edge, to_remove_edges, i, e)
7900 /* Update SWITCH_EXPR case label vector. */
7901 FOR_EACH_VEC_ELT (switch_update, to_update_switch_stmts, i, su)
7904 size_t n = TREE_VEC_LENGTH (su->vec);
7906 gimple_switch_set_num_labels (su->stmt, n);
7907 for (j = 0; j < n; j++)
7908 gimple_switch_set_label (su->stmt, j, TREE_VEC_ELT (su->vec, j));
7909 /* As we may have replaced the default label with a regular one
7910 make sure to make it a real default label again. This ensures
7911 optimal expansion. */
7912 label = gimple_switch_default_label (su->stmt);
7913 CASE_LOW (label) = NULL_TREE;
7914 CASE_HIGH (label) = NULL_TREE;
7917 if (VEC_length (edge, to_remove_edges) > 0)
7918 free_dominance_info (CDI_DOMINATORS);
7920 VEC_free (edge, heap, to_remove_edges);
7921 VEC_free (switch_update, heap, to_update_switch_stmts);
7922 threadedge_finalize_values ();
7925 loop_optimizer_finalize ();
7932 return flag_tree_vrp != 0;
7935 struct gimple_opt_pass pass_vrp =
7940 gate_vrp, /* gate */
7941 execute_vrp, /* execute */
7944 0, /* static_pass_number */
7945 TV_TREE_VRP, /* tv_id */
7946 PROP_ssa, /* properties_required */
7947 0, /* properties_provided */
7948 0, /* properties_destroyed */
7949 0, /* todo_flags_start */
7954 | TODO_ggc_collect /* todo_flags_finish */