1 /* Support routines for Value Range Propagation (VRP).
2 Copyright (C) 2005, 2006, 2007, 2008, 2009, 2010
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"
40 #include "tree-scalar-evolution.h"
41 #include "tree-ssa-propagate.h"
42 #include "tree-chrec.h"
45 /* Type of value ranges. See value_range_d for a description of these
47 enum value_range_type { VR_UNDEFINED, VR_RANGE, VR_ANTI_RANGE, VR_VARYING };
49 /* Range of values that can be associated with an SSA_NAME after VRP
53 /* Lattice value represented by this range. */
54 enum value_range_type type;
56 /* Minimum and maximum values represented by this range. These
57 values should be interpreted as follows:
59 - If TYPE is VR_UNDEFINED or VR_VARYING then MIN and MAX must
62 - If TYPE == VR_RANGE then MIN holds the minimum value and
63 MAX holds the maximum value of the range [MIN, MAX].
65 - If TYPE == ANTI_RANGE the variable is known to NOT
66 take any values in the range [MIN, MAX]. */
70 /* Set of SSA names whose value ranges are equivalent to this one.
71 This set is only valid when TYPE is VR_RANGE or VR_ANTI_RANGE. */
75 typedef struct value_range_d value_range_t;
77 /* Set of SSA names found live during the RPO traversal of the function
78 for still active basic-blocks. */
81 /* Return true if the SSA name NAME is live on the edge E. */
84 live_on_edge (edge e, tree name)
86 return (live[e->dest->index]
87 && TEST_BIT (live[e->dest->index], SSA_NAME_VERSION (name)));
90 /* Local functions. */
91 static int compare_values (tree val1, tree val2);
92 static int compare_values_warnv (tree val1, tree val2, bool *);
93 static void vrp_meet (value_range_t *, value_range_t *);
94 static tree vrp_evaluate_conditional_warnv_with_ops (enum tree_code,
95 tree, tree, bool, bool *,
98 /* Location information for ASSERT_EXPRs. Each instance of this
99 structure describes an ASSERT_EXPR for an SSA name. Since a single
100 SSA name may have more than one assertion associated with it, these
101 locations are kept in a linked list attached to the corresponding
103 struct assert_locus_d
105 /* Basic block where the assertion would be inserted. */
108 /* Some assertions need to be inserted on an edge (e.g., assertions
109 generated by COND_EXPRs). In those cases, BB will be NULL. */
112 /* Pointer to the statement that generated this assertion. */
113 gimple_stmt_iterator si;
115 /* Predicate code for the ASSERT_EXPR. Must be COMPARISON_CLASS_P. */
116 enum tree_code comp_code;
118 /* Value being compared against. */
121 /* Expression to compare. */
124 /* Next node in the linked list. */
125 struct assert_locus_d *next;
128 typedef struct assert_locus_d *assert_locus_t;
130 /* If bit I is present, it means that SSA name N_i has a list of
131 assertions that should be inserted in the IL. */
132 static bitmap need_assert_for;
134 /* Array of locations lists where to insert assertions. ASSERTS_FOR[I]
135 holds a list of ASSERT_LOCUS_T nodes that describe where
136 ASSERT_EXPRs for SSA name N_I should be inserted. */
137 static assert_locus_t *asserts_for;
139 /* Value range array. After propagation, VR_VALUE[I] holds the range
140 of values that SSA name N_I may take. */
141 static value_range_t **vr_value;
143 /* For a PHI node which sets SSA name N_I, VR_COUNTS[I] holds the
144 number of executable edges we saw the last time we visited the
146 static int *vr_phi_edge_counts;
153 static VEC (edge, heap) *to_remove_edges;
154 DEF_VEC_O(switch_update);
155 DEF_VEC_ALLOC_O(switch_update, heap);
156 static VEC (switch_update, heap) *to_update_switch_stmts;
159 /* Return the maximum value for TYPE. */
162 vrp_val_max (const_tree type)
164 if (!INTEGRAL_TYPE_P (type))
167 return TYPE_MAX_VALUE (type);
170 /* Return the minimum value for TYPE. */
173 vrp_val_min (const_tree type)
175 if (!INTEGRAL_TYPE_P (type))
178 return TYPE_MIN_VALUE (type);
181 /* Return whether VAL is equal to the maximum value of its type. This
182 will be true for a positive overflow infinity. We can't do a
183 simple equality comparison with TYPE_MAX_VALUE because C typedefs
184 and Ada subtypes can produce types whose TYPE_MAX_VALUE is not ==
185 to the integer constant with the same value in the type. */
188 vrp_val_is_max (const_tree val)
190 tree type_max = vrp_val_max (TREE_TYPE (val));
191 return (val == type_max
192 || (type_max != NULL_TREE
193 && operand_equal_p (val, type_max, 0)));
196 /* Return whether VAL is equal to the minimum value of its type. This
197 will be true for a negative overflow infinity. */
200 vrp_val_is_min (const_tree val)
202 tree type_min = vrp_val_min (TREE_TYPE (val));
203 return (val == type_min
204 || (type_min != NULL_TREE
205 && operand_equal_p (val, type_min, 0)));
209 /* Return whether TYPE should use an overflow infinity distinct from
210 TYPE_{MIN,MAX}_VALUE. We use an overflow infinity value to
211 represent a signed overflow during VRP computations. An infinity
212 is distinct from a half-range, which will go from some number to
213 TYPE_{MIN,MAX}_VALUE. */
216 needs_overflow_infinity (const_tree type)
218 return INTEGRAL_TYPE_P (type) && !TYPE_OVERFLOW_WRAPS (type);
221 /* Return whether TYPE can support our overflow infinity
222 representation: we use the TREE_OVERFLOW flag, which only exists
223 for constants. If TYPE doesn't support this, we don't optimize
224 cases which would require signed overflow--we drop them to
228 supports_overflow_infinity (const_tree type)
230 tree min = vrp_val_min (type), max = vrp_val_max (type);
231 #ifdef ENABLE_CHECKING
232 gcc_assert (needs_overflow_infinity (type));
234 return (min != NULL_TREE
235 && CONSTANT_CLASS_P (min)
237 && CONSTANT_CLASS_P (max));
240 /* VAL is the maximum or minimum value of a type. Return a
241 corresponding overflow infinity. */
244 make_overflow_infinity (tree val)
246 gcc_checking_assert (val != NULL_TREE && CONSTANT_CLASS_P (val));
247 val = copy_node (val);
248 TREE_OVERFLOW (val) = 1;
252 /* Return a negative overflow infinity for TYPE. */
255 negative_overflow_infinity (tree type)
257 gcc_checking_assert (supports_overflow_infinity (type));
258 return make_overflow_infinity (vrp_val_min (type));
261 /* Return a positive overflow infinity for TYPE. */
264 positive_overflow_infinity (tree type)
266 gcc_checking_assert (supports_overflow_infinity (type));
267 return make_overflow_infinity (vrp_val_max (type));
270 /* Return whether VAL is a negative overflow infinity. */
273 is_negative_overflow_infinity (const_tree val)
275 return (needs_overflow_infinity (TREE_TYPE (val))
276 && CONSTANT_CLASS_P (val)
277 && TREE_OVERFLOW (val)
278 && vrp_val_is_min (val));
281 /* Return whether VAL is a positive overflow infinity. */
284 is_positive_overflow_infinity (const_tree val)
286 return (needs_overflow_infinity (TREE_TYPE (val))
287 && CONSTANT_CLASS_P (val)
288 && TREE_OVERFLOW (val)
289 && vrp_val_is_max (val));
292 /* Return whether VAL is a positive or negative overflow infinity. */
295 is_overflow_infinity (const_tree val)
297 return (needs_overflow_infinity (TREE_TYPE (val))
298 && CONSTANT_CLASS_P (val)
299 && TREE_OVERFLOW (val)
300 && (vrp_val_is_min (val) || vrp_val_is_max (val)));
303 /* Return whether STMT has a constant rhs that is_overflow_infinity. */
306 stmt_overflow_infinity (gimple stmt)
308 if (is_gimple_assign (stmt)
309 && get_gimple_rhs_class (gimple_assign_rhs_code (stmt)) ==
311 return is_overflow_infinity (gimple_assign_rhs1 (stmt));
315 /* If VAL is now an overflow infinity, return VAL. Otherwise, return
316 the same value with TREE_OVERFLOW clear. This can be used to avoid
317 confusing a regular value with an overflow value. */
320 avoid_overflow_infinity (tree val)
322 if (!is_overflow_infinity (val))
325 if (vrp_val_is_max (val))
326 return vrp_val_max (TREE_TYPE (val));
329 gcc_checking_assert (vrp_val_is_min (val));
330 return vrp_val_min (TREE_TYPE (val));
335 /* Return true if ARG is marked with the nonnull attribute in the
336 current function signature. */
339 nonnull_arg_p (const_tree arg)
341 tree t, attrs, fntype;
342 unsigned HOST_WIDE_INT arg_num;
344 gcc_assert (TREE_CODE (arg) == PARM_DECL && POINTER_TYPE_P (TREE_TYPE (arg)));
346 /* The static chain decl is always non null. */
347 if (arg == cfun->static_chain_decl)
350 fntype = TREE_TYPE (current_function_decl);
351 attrs = lookup_attribute ("nonnull", TYPE_ATTRIBUTES (fntype));
353 /* If "nonnull" wasn't specified, we know nothing about the argument. */
354 if (attrs == NULL_TREE)
357 /* If "nonnull" applies to all the arguments, then ARG is non-null. */
358 if (TREE_VALUE (attrs) == NULL_TREE)
361 /* Get the position number for ARG in the function signature. */
362 for (arg_num = 1, t = DECL_ARGUMENTS (current_function_decl);
364 t = DECL_CHAIN (t), arg_num++)
370 gcc_assert (t == arg);
372 /* Now see if ARG_NUM is mentioned in the nonnull list. */
373 for (t = TREE_VALUE (attrs); t; t = TREE_CHAIN (t))
375 if (compare_tree_int (TREE_VALUE (t), arg_num) == 0)
383 /* Set value range VR to VR_VARYING. */
386 set_value_range_to_varying (value_range_t *vr)
388 vr->type = VR_VARYING;
389 vr->min = vr->max = NULL_TREE;
391 bitmap_clear (vr->equiv);
395 /* Set value range VR to {T, MIN, MAX, EQUIV}. */
398 set_value_range (value_range_t *vr, enum value_range_type t, tree min,
399 tree max, bitmap equiv)
401 #if defined ENABLE_CHECKING
402 /* Check the validity of the range. */
403 if (t == VR_RANGE || t == VR_ANTI_RANGE)
407 gcc_assert (min && max);
409 if (INTEGRAL_TYPE_P (TREE_TYPE (min)) && t == VR_ANTI_RANGE)
410 gcc_assert (!vrp_val_is_min (min) || !vrp_val_is_max (max));
412 cmp = compare_values (min, max);
413 gcc_assert (cmp == 0 || cmp == -1 || cmp == -2);
415 if (needs_overflow_infinity (TREE_TYPE (min)))
416 gcc_assert (!is_overflow_infinity (min)
417 || !is_overflow_infinity (max));
420 if (t == VR_UNDEFINED || t == VR_VARYING)
421 gcc_assert (min == NULL_TREE && max == NULL_TREE);
423 if (t == VR_UNDEFINED || t == VR_VARYING)
424 gcc_assert (equiv == NULL || bitmap_empty_p (equiv));
431 /* Since updating the equivalence set involves deep copying the
432 bitmaps, only do it if absolutely necessary. */
433 if (vr->equiv == NULL
435 vr->equiv = BITMAP_ALLOC (NULL);
437 if (equiv != vr->equiv)
439 if (equiv && !bitmap_empty_p (equiv))
440 bitmap_copy (vr->equiv, equiv);
442 bitmap_clear (vr->equiv);
447 /* Set value range VR to the canonical form of {T, MIN, MAX, EQUIV}.
448 This means adjusting T, MIN and MAX representing the case of a
449 wrapping range with MAX < MIN covering [MIN, type_max] U [type_min, MAX]
450 as anti-rage ~[MAX+1, MIN-1]. Likewise for wrapping anti-ranges.
451 In corner cases where MAX+1 or MIN-1 wraps this will fall back
453 This routine exists to ease canonicalization in the case where we
454 extract ranges from var + CST op limit. */
457 set_and_canonicalize_value_range (value_range_t *vr, enum value_range_type t,
458 tree min, tree max, bitmap equiv)
460 /* Nothing to canonicalize for symbolic or unknown or varying ranges. */
462 && t != VR_ANTI_RANGE)
463 || TREE_CODE (min) != INTEGER_CST
464 || TREE_CODE (max) != INTEGER_CST)
466 set_value_range (vr, t, min, max, equiv);
470 /* Wrong order for min and max, to swap them and the VR type we need
472 if (tree_int_cst_lt (max, min))
474 tree one = build_int_cst (TREE_TYPE (min), 1);
475 tree tmp = int_const_binop (PLUS_EXPR, max, one, 0);
476 max = int_const_binop (MINUS_EXPR, min, one, 0);
479 /* There's one corner case, if we had [C+1, C] before we now have
480 that again. But this represents an empty value range, so drop
481 to varying in this case. */
482 if (tree_int_cst_lt (max, min))
484 set_value_range_to_varying (vr);
488 t = t == VR_RANGE ? VR_ANTI_RANGE : VR_RANGE;
491 /* Anti-ranges that can be represented as ranges should be so. */
492 if (t == VR_ANTI_RANGE)
494 bool is_min = vrp_val_is_min (min);
495 bool is_max = vrp_val_is_max (max);
497 if (is_min && is_max)
499 /* We cannot deal with empty ranges, drop to varying. */
500 set_value_range_to_varying (vr);
504 /* As a special exception preserve non-null ranges. */
505 && !(TYPE_UNSIGNED (TREE_TYPE (min))
506 && integer_zerop (max)))
508 tree one = build_int_cst (TREE_TYPE (max), 1);
509 min = int_const_binop (PLUS_EXPR, max, one, 0);
510 max = vrp_val_max (TREE_TYPE (max));
515 tree one = build_int_cst (TREE_TYPE (min), 1);
516 max = int_const_binop (MINUS_EXPR, min, one, 0);
517 min = vrp_val_min (TREE_TYPE (min));
522 set_value_range (vr, t, min, max, equiv);
525 /* Copy value range FROM into value range TO. */
528 copy_value_range (value_range_t *to, value_range_t *from)
530 set_value_range (to, from->type, from->min, from->max, from->equiv);
533 /* Set value range VR to a single value. This function is only called
534 with values we get from statements, and exists to clear the
535 TREE_OVERFLOW flag so that we don't think we have an overflow
536 infinity when we shouldn't. */
539 set_value_range_to_value (value_range_t *vr, tree val, bitmap equiv)
541 gcc_assert (is_gimple_min_invariant (val));
542 val = avoid_overflow_infinity (val);
543 set_value_range (vr, VR_RANGE, val, val, equiv);
546 /* Set value range VR to a non-negative range of type TYPE.
547 OVERFLOW_INFINITY indicates whether to use an overflow infinity
548 rather than TYPE_MAX_VALUE; this should be true if we determine
549 that the range is nonnegative based on the assumption that signed
550 overflow does not occur. */
553 set_value_range_to_nonnegative (value_range_t *vr, tree type,
554 bool overflow_infinity)
558 if (overflow_infinity && !supports_overflow_infinity (type))
560 set_value_range_to_varying (vr);
564 zero = build_int_cst (type, 0);
565 set_value_range (vr, VR_RANGE, zero,
567 ? positive_overflow_infinity (type)
568 : TYPE_MAX_VALUE (type)),
572 /* Set value range VR to a non-NULL range of type TYPE. */
575 set_value_range_to_nonnull (value_range_t *vr, tree type)
577 tree zero = build_int_cst (type, 0);
578 set_value_range (vr, VR_ANTI_RANGE, zero, zero, vr->equiv);
582 /* Set value range VR to a NULL range of type TYPE. */
585 set_value_range_to_null (value_range_t *vr, tree type)
587 set_value_range_to_value (vr, build_int_cst (type, 0), vr->equiv);
591 /* Set value range VR to a range of a truthvalue of type TYPE. */
594 set_value_range_to_truthvalue (value_range_t *vr, tree type)
596 if (TYPE_PRECISION (type) == 1)
597 set_value_range_to_varying (vr);
599 set_value_range (vr, VR_RANGE,
600 build_int_cst (type, 0), build_int_cst (type, 1),
605 /* Set value range VR to VR_UNDEFINED. */
608 set_value_range_to_undefined (value_range_t *vr)
610 vr->type = VR_UNDEFINED;
611 vr->min = vr->max = NULL_TREE;
613 bitmap_clear (vr->equiv);
617 /* If abs (min) < abs (max), set VR to [-max, max], if
618 abs (min) >= abs (max), set VR to [-min, min]. */
621 abs_extent_range (value_range_t *vr, tree min, tree max)
625 gcc_assert (TREE_CODE (min) == INTEGER_CST);
626 gcc_assert (TREE_CODE (max) == INTEGER_CST);
627 gcc_assert (INTEGRAL_TYPE_P (TREE_TYPE (min)));
628 gcc_assert (!TYPE_UNSIGNED (TREE_TYPE (min)));
629 min = fold_unary (ABS_EXPR, TREE_TYPE (min), min);
630 max = fold_unary (ABS_EXPR, TREE_TYPE (max), max);
631 if (TREE_OVERFLOW (min) || TREE_OVERFLOW (max))
633 set_value_range_to_varying (vr);
636 cmp = compare_values (min, max);
638 min = fold_unary (NEGATE_EXPR, TREE_TYPE (min), max);
639 else if (cmp == 0 || cmp == 1)
642 min = fold_unary (NEGATE_EXPR, TREE_TYPE (min), min);
646 set_value_range_to_varying (vr);
649 set_and_canonicalize_value_range (vr, VR_RANGE, min, max, NULL);
653 /* Return value range information for VAR.
655 If we have no values ranges recorded (ie, VRP is not running), then
656 return NULL. Otherwise create an empty range if none existed for VAR. */
658 static value_range_t *
659 get_value_range (const_tree var)
663 unsigned ver = SSA_NAME_VERSION (var);
665 /* If we have no recorded ranges, then return NULL. */
673 /* Create a default value range. */
674 vr_value[ver] = vr = XCNEW (value_range_t);
676 /* Defer allocating the equivalence set. */
679 /* If VAR is a default definition, the variable can take any value
681 sym = SSA_NAME_VAR (var);
682 if (SSA_NAME_IS_DEFAULT_DEF (var))
684 /* Try to use the "nonnull" attribute to create ~[0, 0]
685 anti-ranges for pointers. Note that this is only valid with
686 default definitions of PARM_DECLs. */
687 if (TREE_CODE (sym) == PARM_DECL
688 && POINTER_TYPE_P (TREE_TYPE (sym))
689 && nonnull_arg_p (sym))
690 set_value_range_to_nonnull (vr, TREE_TYPE (sym));
692 set_value_range_to_varying (vr);
698 /* Return true, if VAL1 and VAL2 are equal values for VRP purposes. */
701 vrp_operand_equal_p (const_tree val1, const_tree val2)
705 if (!val1 || !val2 || !operand_equal_p (val1, val2, 0))
707 if (is_overflow_infinity (val1))
708 return is_overflow_infinity (val2);
712 /* Return true, if the bitmaps B1 and B2 are equal. */
715 vrp_bitmap_equal_p (const_bitmap b1, const_bitmap b2)
719 && bitmap_equal_p (b1, b2)));
722 /* Update the value range and equivalence set for variable VAR to
723 NEW_VR. Return true if NEW_VR is different from VAR's previous
726 NOTE: This function assumes that NEW_VR is a temporary value range
727 object created for the sole purpose of updating VAR's range. The
728 storage used by the equivalence set from NEW_VR will be freed by
729 this function. Do not call update_value_range when NEW_VR
730 is the range object associated with another SSA name. */
733 update_value_range (const_tree var, value_range_t *new_vr)
735 value_range_t *old_vr;
738 /* Update the value range, if necessary. */
739 old_vr = get_value_range (var);
740 is_new = old_vr->type != new_vr->type
741 || !vrp_operand_equal_p (old_vr->min, new_vr->min)
742 || !vrp_operand_equal_p (old_vr->max, new_vr->max)
743 || !vrp_bitmap_equal_p (old_vr->equiv, new_vr->equiv);
746 set_value_range (old_vr, new_vr->type, new_vr->min, new_vr->max,
749 BITMAP_FREE (new_vr->equiv);
755 /* Add VAR and VAR's equivalence set to EQUIV. This is the central
756 point where equivalence processing can be turned on/off. */
759 add_equivalence (bitmap *equiv, const_tree var)
761 unsigned ver = SSA_NAME_VERSION (var);
762 value_range_t *vr = vr_value[ver];
765 *equiv = BITMAP_ALLOC (NULL);
766 bitmap_set_bit (*equiv, ver);
768 bitmap_ior_into (*equiv, vr->equiv);
772 /* Return true if VR is ~[0, 0]. */
775 range_is_nonnull (value_range_t *vr)
777 return vr->type == VR_ANTI_RANGE
778 && integer_zerop (vr->min)
779 && integer_zerop (vr->max);
783 /* Return true if VR is [0, 0]. */
786 range_is_null (value_range_t *vr)
788 return vr->type == VR_RANGE
789 && integer_zerop (vr->min)
790 && integer_zerop (vr->max);
793 /* Return true if max and min of VR are INTEGER_CST. It's not necessary
797 range_int_cst_p (value_range_t *vr)
799 return (vr->type == VR_RANGE
800 && TREE_CODE (vr->max) == INTEGER_CST
801 && TREE_CODE (vr->min) == INTEGER_CST
802 && !TREE_OVERFLOW (vr->max)
803 && !TREE_OVERFLOW (vr->min));
806 /* Return true if VR is a INTEGER_CST singleton. */
809 range_int_cst_singleton_p (value_range_t *vr)
811 return (range_int_cst_p (vr)
812 && tree_int_cst_equal (vr->min, vr->max));
815 /* Return true if value range VR involves at least one symbol. */
818 symbolic_range_p (value_range_t *vr)
820 return (!is_gimple_min_invariant (vr->min)
821 || !is_gimple_min_invariant (vr->max));
824 /* Return true if value range VR uses an overflow infinity. */
827 overflow_infinity_range_p (value_range_t *vr)
829 return (vr->type == VR_RANGE
830 && (is_overflow_infinity (vr->min)
831 || is_overflow_infinity (vr->max)));
834 /* Return false if we can not make a valid comparison based on VR;
835 this will be the case if it uses an overflow infinity and overflow
836 is not undefined (i.e., -fno-strict-overflow is in effect).
837 Otherwise return true, and set *STRICT_OVERFLOW_P to true if VR
838 uses an overflow infinity. */
841 usable_range_p (value_range_t *vr, bool *strict_overflow_p)
843 gcc_assert (vr->type == VR_RANGE);
844 if (is_overflow_infinity (vr->min))
846 *strict_overflow_p = true;
847 if (!TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (vr->min)))
850 if (is_overflow_infinity (vr->max))
852 *strict_overflow_p = true;
853 if (!TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (vr->max)))
860 /* Like tree_expr_nonnegative_warnv_p, but this function uses value
861 ranges obtained so far. */
864 vrp_expr_computes_nonnegative (tree expr, bool *strict_overflow_p)
866 return (tree_expr_nonnegative_warnv_p (expr, strict_overflow_p)
867 || (TREE_CODE (expr) == SSA_NAME
868 && ssa_name_nonnegative_p (expr)));
871 /* Return true if the result of assignment STMT is know to be non-negative.
872 If the return value is based on the assumption that signed overflow is
873 undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't change
874 *STRICT_OVERFLOW_P.*/
877 gimple_assign_nonnegative_warnv_p (gimple stmt, bool *strict_overflow_p)
879 enum tree_code code = gimple_assign_rhs_code (stmt);
880 switch (get_gimple_rhs_class (code))
882 case GIMPLE_UNARY_RHS:
883 return tree_unary_nonnegative_warnv_p (gimple_assign_rhs_code (stmt),
884 gimple_expr_type (stmt),
885 gimple_assign_rhs1 (stmt),
887 case GIMPLE_BINARY_RHS:
888 return tree_binary_nonnegative_warnv_p (gimple_assign_rhs_code (stmt),
889 gimple_expr_type (stmt),
890 gimple_assign_rhs1 (stmt),
891 gimple_assign_rhs2 (stmt),
893 case GIMPLE_TERNARY_RHS:
895 case GIMPLE_SINGLE_RHS:
896 return tree_single_nonnegative_warnv_p (gimple_assign_rhs1 (stmt),
898 case GIMPLE_INVALID_RHS:
905 /* Return true if return value of call STMT is know to be non-negative.
906 If the return value is based on the assumption that signed overflow is
907 undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't change
908 *STRICT_OVERFLOW_P.*/
911 gimple_call_nonnegative_warnv_p (gimple stmt, bool *strict_overflow_p)
913 tree arg0 = gimple_call_num_args (stmt) > 0 ?
914 gimple_call_arg (stmt, 0) : NULL_TREE;
915 tree arg1 = gimple_call_num_args (stmt) > 1 ?
916 gimple_call_arg (stmt, 1) : NULL_TREE;
918 return tree_call_nonnegative_warnv_p (gimple_expr_type (stmt),
919 gimple_call_fndecl (stmt),
925 /* Return true if STMT is know to to compute a non-negative value.
926 If the return value is based on the assumption that signed overflow is
927 undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't change
928 *STRICT_OVERFLOW_P.*/
931 gimple_stmt_nonnegative_warnv_p (gimple stmt, bool *strict_overflow_p)
933 switch (gimple_code (stmt))
936 return gimple_assign_nonnegative_warnv_p (stmt, strict_overflow_p);
938 return gimple_call_nonnegative_warnv_p (stmt, strict_overflow_p);
944 /* Return true if the result of assignment STMT is know to be non-zero.
945 If the return value is based on the assumption that signed overflow is
946 undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't change
947 *STRICT_OVERFLOW_P.*/
950 gimple_assign_nonzero_warnv_p (gimple stmt, bool *strict_overflow_p)
952 enum tree_code code = gimple_assign_rhs_code (stmt);
953 switch (get_gimple_rhs_class (code))
955 case GIMPLE_UNARY_RHS:
956 return tree_unary_nonzero_warnv_p (gimple_assign_rhs_code (stmt),
957 gimple_expr_type (stmt),
958 gimple_assign_rhs1 (stmt),
960 case GIMPLE_BINARY_RHS:
961 return tree_binary_nonzero_warnv_p (gimple_assign_rhs_code (stmt),
962 gimple_expr_type (stmt),
963 gimple_assign_rhs1 (stmt),
964 gimple_assign_rhs2 (stmt),
966 case GIMPLE_TERNARY_RHS:
968 case GIMPLE_SINGLE_RHS:
969 return tree_single_nonzero_warnv_p (gimple_assign_rhs1 (stmt),
971 case GIMPLE_INVALID_RHS:
978 /* Return true if STMT is know to to compute a non-zero value.
979 If the return value is based on the assumption that signed overflow is
980 undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't change
981 *STRICT_OVERFLOW_P.*/
984 gimple_stmt_nonzero_warnv_p (gimple stmt, bool *strict_overflow_p)
986 switch (gimple_code (stmt))
989 return gimple_assign_nonzero_warnv_p (stmt, strict_overflow_p);
991 return gimple_alloca_call_p (stmt);
997 /* Like tree_expr_nonzero_warnv_p, but this function uses value ranges
1001 vrp_stmt_computes_nonzero (gimple stmt, bool *strict_overflow_p)
1003 if (gimple_stmt_nonzero_warnv_p (stmt, strict_overflow_p))
1006 /* If we have an expression of the form &X->a, then the expression
1007 is nonnull if X is nonnull. */
1008 if (is_gimple_assign (stmt)
1009 && gimple_assign_rhs_code (stmt) == ADDR_EXPR)
1011 tree expr = gimple_assign_rhs1 (stmt);
1012 tree base = get_base_address (TREE_OPERAND (expr, 0));
1014 if (base != NULL_TREE
1015 && TREE_CODE (base) == MEM_REF
1016 && TREE_CODE (TREE_OPERAND (base, 0)) == SSA_NAME)
1018 value_range_t *vr = get_value_range (TREE_OPERAND (base, 0));
1019 if (range_is_nonnull (vr))
1027 /* Returns true if EXPR is a valid value (as expected by compare_values) --
1028 a gimple invariant, or SSA_NAME +- CST. */
1031 valid_value_p (tree expr)
1033 if (TREE_CODE (expr) == SSA_NAME)
1036 if (TREE_CODE (expr) == PLUS_EXPR
1037 || TREE_CODE (expr) == MINUS_EXPR)
1038 return (TREE_CODE (TREE_OPERAND (expr, 0)) == SSA_NAME
1039 && TREE_CODE (TREE_OPERAND (expr, 1)) == INTEGER_CST);
1041 return is_gimple_min_invariant (expr);
1047 -2 if those are incomparable. */
1049 operand_less_p (tree val, tree val2)
1051 /* LT is folded faster than GE and others. Inline the common case. */
1052 if (TREE_CODE (val) == INTEGER_CST && TREE_CODE (val2) == INTEGER_CST)
1054 if (TYPE_UNSIGNED (TREE_TYPE (val)))
1055 return INT_CST_LT_UNSIGNED (val, val2);
1058 if (INT_CST_LT (val, val2))
1066 fold_defer_overflow_warnings ();
1068 tcmp = fold_binary_to_constant (LT_EXPR, boolean_type_node, val, val2);
1070 fold_undefer_and_ignore_overflow_warnings ();
1073 || TREE_CODE (tcmp) != INTEGER_CST)
1076 if (!integer_zerop (tcmp))
1080 /* val >= val2, not considering overflow infinity. */
1081 if (is_negative_overflow_infinity (val))
1082 return is_negative_overflow_infinity (val2) ? 0 : 1;
1083 else if (is_positive_overflow_infinity (val2))
1084 return is_positive_overflow_infinity (val) ? 0 : 1;
1089 /* Compare two values VAL1 and VAL2. Return
1091 -2 if VAL1 and VAL2 cannot be compared at compile-time,
1094 +1 if VAL1 > VAL2, and
1097 This is similar to tree_int_cst_compare but supports pointer values
1098 and values that cannot be compared at compile time.
1100 If STRICT_OVERFLOW_P is not NULL, then set *STRICT_OVERFLOW_P to
1101 true if the return value is only valid if we assume that signed
1102 overflow is undefined. */
1105 compare_values_warnv (tree val1, tree val2, bool *strict_overflow_p)
1110 /* Below we rely on the fact that VAL1 and VAL2 are both pointers or
1112 gcc_assert (POINTER_TYPE_P (TREE_TYPE (val1))
1113 == POINTER_TYPE_P (TREE_TYPE (val2)));
1114 /* Convert the two values into the same type. This is needed because
1115 sizetype causes sign extension even for unsigned types. */
1116 val2 = fold_convert (TREE_TYPE (val1), val2);
1117 STRIP_USELESS_TYPE_CONVERSION (val2);
1119 if ((TREE_CODE (val1) == SSA_NAME
1120 || TREE_CODE (val1) == PLUS_EXPR
1121 || TREE_CODE (val1) == MINUS_EXPR)
1122 && (TREE_CODE (val2) == SSA_NAME
1123 || TREE_CODE (val2) == PLUS_EXPR
1124 || TREE_CODE (val2) == MINUS_EXPR))
1126 tree n1, c1, n2, c2;
1127 enum tree_code code1, code2;
1129 /* If VAL1 and VAL2 are of the form 'NAME [+-] CST' or 'NAME',
1130 return -1 or +1 accordingly. If VAL1 and VAL2 don't use the
1131 same name, return -2. */
1132 if (TREE_CODE (val1) == SSA_NAME)
1140 code1 = TREE_CODE (val1);
1141 n1 = TREE_OPERAND (val1, 0);
1142 c1 = TREE_OPERAND (val1, 1);
1143 if (tree_int_cst_sgn (c1) == -1)
1145 if (is_negative_overflow_infinity (c1))
1147 c1 = fold_unary_to_constant (NEGATE_EXPR, TREE_TYPE (c1), c1);
1150 code1 = code1 == MINUS_EXPR ? PLUS_EXPR : MINUS_EXPR;
1154 if (TREE_CODE (val2) == SSA_NAME)
1162 code2 = TREE_CODE (val2);
1163 n2 = TREE_OPERAND (val2, 0);
1164 c2 = TREE_OPERAND (val2, 1);
1165 if (tree_int_cst_sgn (c2) == -1)
1167 if (is_negative_overflow_infinity (c2))
1169 c2 = fold_unary_to_constant (NEGATE_EXPR, TREE_TYPE (c2), c2);
1172 code2 = code2 == MINUS_EXPR ? PLUS_EXPR : MINUS_EXPR;
1176 /* Both values must use the same name. */
1180 if (code1 == SSA_NAME
1181 && code2 == SSA_NAME)
1185 /* If overflow is defined we cannot simplify more. */
1186 if (!TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (val1)))
1189 if (strict_overflow_p != NULL
1190 && (code1 == SSA_NAME || !TREE_NO_WARNING (val1))
1191 && (code2 == SSA_NAME || !TREE_NO_WARNING (val2)))
1192 *strict_overflow_p = true;
1194 if (code1 == SSA_NAME)
1196 if (code2 == PLUS_EXPR)
1197 /* NAME < NAME + CST */
1199 else if (code2 == MINUS_EXPR)
1200 /* NAME > NAME - CST */
1203 else if (code1 == PLUS_EXPR)
1205 if (code2 == SSA_NAME)
1206 /* NAME + CST > NAME */
1208 else if (code2 == PLUS_EXPR)
1209 /* NAME + CST1 > NAME + CST2, if CST1 > CST2 */
1210 return compare_values_warnv (c1, c2, strict_overflow_p);
1211 else if (code2 == MINUS_EXPR)
1212 /* NAME + CST1 > NAME - CST2 */
1215 else if (code1 == MINUS_EXPR)
1217 if (code2 == SSA_NAME)
1218 /* NAME - CST < NAME */
1220 else if (code2 == PLUS_EXPR)
1221 /* NAME - CST1 < NAME + CST2 */
1223 else if (code2 == MINUS_EXPR)
1224 /* NAME - CST1 > NAME - CST2, if CST1 < CST2. Notice that
1225 C1 and C2 are swapped in the call to compare_values. */
1226 return compare_values_warnv (c2, c1, strict_overflow_p);
1232 /* We cannot compare non-constants. */
1233 if (!is_gimple_min_invariant (val1) || !is_gimple_min_invariant (val2))
1236 if (!POINTER_TYPE_P (TREE_TYPE (val1)))
1238 /* We cannot compare overflowed values, except for overflow
1240 if (TREE_OVERFLOW (val1) || TREE_OVERFLOW (val2))
1242 if (strict_overflow_p != NULL)
1243 *strict_overflow_p = true;
1244 if (is_negative_overflow_infinity (val1))
1245 return is_negative_overflow_infinity (val2) ? 0 : -1;
1246 else if (is_negative_overflow_infinity (val2))
1248 else if (is_positive_overflow_infinity (val1))
1249 return is_positive_overflow_infinity (val2) ? 0 : 1;
1250 else if (is_positive_overflow_infinity (val2))
1255 return tree_int_cst_compare (val1, val2);
1261 /* First see if VAL1 and VAL2 are not the same. */
1262 if (val1 == val2 || operand_equal_p (val1, val2, 0))
1265 /* If VAL1 is a lower address than VAL2, return -1. */
1266 if (operand_less_p (val1, val2) == 1)
1269 /* If VAL1 is a higher address than VAL2, return +1. */
1270 if (operand_less_p (val2, val1) == 1)
1273 /* If VAL1 is different than VAL2, return +2.
1274 For integer constants we either have already returned -1 or 1
1275 or they are equivalent. We still might succeed in proving
1276 something about non-trivial operands. */
1277 if (TREE_CODE (val1) != INTEGER_CST
1278 || TREE_CODE (val2) != INTEGER_CST)
1280 t = fold_binary_to_constant (NE_EXPR, boolean_type_node, val1, val2);
1281 if (t && integer_onep (t))
1289 /* Compare values like compare_values_warnv, but treat comparisons of
1290 nonconstants which rely on undefined overflow as incomparable. */
1293 compare_values (tree val1, tree val2)
1299 ret = compare_values_warnv (val1, val2, &sop);
1301 && (!is_gimple_min_invariant (val1) || !is_gimple_min_invariant (val2)))
1307 /* Return 1 if VAL is inside value range VR (VR->MIN <= VAL <= VR->MAX),
1308 0 if VAL is not inside VR,
1309 -2 if we cannot tell either way.
1311 FIXME, the current semantics of this functions are a bit quirky
1312 when taken in the context of VRP. In here we do not care
1313 about VR's type. If VR is the anti-range ~[3, 5] the call
1314 value_inside_range (4, VR) will return 1.
1316 This is counter-intuitive in a strict sense, but the callers
1317 currently expect this. They are calling the function
1318 merely to determine whether VR->MIN <= VAL <= VR->MAX. The
1319 callers are applying the VR_RANGE/VR_ANTI_RANGE semantics
1322 This also applies to value_ranges_intersect_p and
1323 range_includes_zero_p. The semantics of VR_RANGE and
1324 VR_ANTI_RANGE should be encoded here, but that also means
1325 adapting the users of these functions to the new semantics.
1327 Benchmark compile/20001226-1.c compilation time after changing this
1331 value_inside_range (tree val, value_range_t * vr)
1335 cmp1 = operand_less_p (val, vr->min);
1341 cmp2 = operand_less_p (vr->max, val);
1349 /* Return true if value ranges VR0 and VR1 have a non-empty
1352 Benchmark compile/20001226-1.c compilation time after changing this
1357 value_ranges_intersect_p (value_range_t *vr0, value_range_t *vr1)
1359 /* The value ranges do not intersect if the maximum of the first range is
1360 less than the minimum of the second range or vice versa.
1361 When those relations are unknown, we can't do any better. */
1362 if (operand_less_p (vr0->max, vr1->min) != 0)
1364 if (operand_less_p (vr1->max, vr0->min) != 0)
1370 /* Return true if VR includes the value zero, false otherwise. FIXME,
1371 currently this will return false for an anti-range like ~[-4, 3].
1372 This will be wrong when the semantics of value_inside_range are
1373 modified (currently the users of this function expect these
1377 range_includes_zero_p (value_range_t *vr)
1381 gcc_assert (vr->type != VR_UNDEFINED
1382 && vr->type != VR_VARYING
1383 && !symbolic_range_p (vr));
1385 zero = build_int_cst (TREE_TYPE (vr->min), 0);
1386 return (value_inside_range (zero, vr) == 1);
1389 /* Return true if T, an SSA_NAME, is known to be nonnegative. Return
1390 false otherwise or if no value range information is available. */
1393 ssa_name_nonnegative_p (const_tree t)
1395 value_range_t *vr = get_value_range (t);
1397 if (INTEGRAL_TYPE_P (t)
1398 && TYPE_UNSIGNED (t))
1404 /* Testing for VR_ANTI_RANGE is not useful here as any anti-range
1405 which would return a useful value should be encoded as a VR_RANGE. */
1406 if (vr->type == VR_RANGE)
1408 int result = compare_values (vr->min, integer_zero_node);
1410 return (result == 0 || result == 1);
1415 /* If OP has a value range with a single constant value return that,
1416 otherwise return NULL_TREE. This returns OP itself if OP is a
1420 op_with_constant_singleton_value_range (tree op)
1424 if (is_gimple_min_invariant (op))
1427 if (TREE_CODE (op) != SSA_NAME)
1430 vr = get_value_range (op);
1431 if (vr->type == VR_RANGE
1432 && operand_equal_p (vr->min, vr->max, 0)
1433 && is_gimple_min_invariant (vr->min))
1440 /* Extract value range information from an ASSERT_EXPR EXPR and store
1444 extract_range_from_assert (value_range_t *vr_p, tree expr)
1446 tree var, cond, limit, min, max, type;
1447 value_range_t *var_vr, *limit_vr;
1448 enum tree_code cond_code;
1450 var = ASSERT_EXPR_VAR (expr);
1451 cond = ASSERT_EXPR_COND (expr);
1453 gcc_assert (COMPARISON_CLASS_P (cond));
1455 /* Find VAR in the ASSERT_EXPR conditional. */
1456 if (var == TREE_OPERAND (cond, 0)
1457 || TREE_CODE (TREE_OPERAND (cond, 0)) == PLUS_EXPR
1458 || TREE_CODE (TREE_OPERAND (cond, 0)) == NOP_EXPR)
1460 /* If the predicate is of the form VAR COMP LIMIT, then we just
1461 take LIMIT from the RHS and use the same comparison code. */
1462 cond_code = TREE_CODE (cond);
1463 limit = TREE_OPERAND (cond, 1);
1464 cond = TREE_OPERAND (cond, 0);
1468 /* If the predicate is of the form LIMIT COMP VAR, then we need
1469 to flip around the comparison code to create the proper range
1471 cond_code = swap_tree_comparison (TREE_CODE (cond));
1472 limit = TREE_OPERAND (cond, 0);
1473 cond = TREE_OPERAND (cond, 1);
1476 limit = avoid_overflow_infinity (limit);
1478 type = TREE_TYPE (limit);
1479 gcc_assert (limit != var);
1481 /* For pointer arithmetic, we only keep track of pointer equality
1483 if (POINTER_TYPE_P (type) && cond_code != NE_EXPR && cond_code != EQ_EXPR)
1485 set_value_range_to_varying (vr_p);
1489 /* If LIMIT is another SSA name and LIMIT has a range of its own,
1490 try to use LIMIT's range to avoid creating symbolic ranges
1492 limit_vr = (TREE_CODE (limit) == SSA_NAME) ? get_value_range (limit) : NULL;
1494 /* LIMIT's range is only interesting if it has any useful information. */
1496 && (limit_vr->type == VR_UNDEFINED
1497 || limit_vr->type == VR_VARYING
1498 || symbolic_range_p (limit_vr)))
1501 /* Initially, the new range has the same set of equivalences of
1502 VAR's range. This will be revised before returning the final
1503 value. Since assertions may be chained via mutually exclusive
1504 predicates, we will need to trim the set of equivalences before
1506 gcc_assert (vr_p->equiv == NULL);
1507 add_equivalence (&vr_p->equiv, var);
1509 /* Extract a new range based on the asserted comparison for VAR and
1510 LIMIT's value range. Notice that if LIMIT has an anti-range, we
1511 will only use it for equality comparisons (EQ_EXPR). For any
1512 other kind of assertion, we cannot derive a range from LIMIT's
1513 anti-range that can be used to describe the new range. For
1514 instance, ASSERT_EXPR <x_2, x_2 <= b_4>. If b_4 is ~[2, 10],
1515 then b_4 takes on the ranges [-INF, 1] and [11, +INF]. There is
1516 no single range for x_2 that could describe LE_EXPR, so we might
1517 as well build the range [b_4, +INF] for it.
1518 One special case we handle is extracting a range from a
1519 range test encoded as (unsigned)var + CST <= limit. */
1520 if (TREE_CODE (cond) == NOP_EXPR
1521 || TREE_CODE (cond) == PLUS_EXPR)
1523 if (TREE_CODE (cond) == PLUS_EXPR)
1525 min = fold_build1 (NEGATE_EXPR, TREE_TYPE (TREE_OPERAND (cond, 1)),
1526 TREE_OPERAND (cond, 1));
1527 max = int_const_binop (PLUS_EXPR, limit, min, 0);
1528 cond = TREE_OPERAND (cond, 0);
1532 min = build_int_cst (TREE_TYPE (var), 0);
1536 /* Make sure to not set TREE_OVERFLOW on the final type
1537 conversion. We are willingly interpreting large positive
1538 unsigned values as negative singed values here. */
1539 min = force_fit_type_double (TREE_TYPE (var), tree_to_double_int (min),
1541 max = force_fit_type_double (TREE_TYPE (var), tree_to_double_int (max),
1544 /* We can transform a max, min range to an anti-range or
1545 vice-versa. Use set_and_canonicalize_value_range which does
1547 if (cond_code == LE_EXPR)
1548 set_and_canonicalize_value_range (vr_p, VR_RANGE,
1549 min, max, vr_p->equiv);
1550 else if (cond_code == GT_EXPR)
1551 set_and_canonicalize_value_range (vr_p, VR_ANTI_RANGE,
1552 min, max, vr_p->equiv);
1556 else if (cond_code == EQ_EXPR)
1558 enum value_range_type range_type;
1562 range_type = limit_vr->type;
1563 min = limit_vr->min;
1564 max = limit_vr->max;
1568 range_type = VR_RANGE;
1573 set_value_range (vr_p, range_type, min, max, vr_p->equiv);
1575 /* When asserting the equality VAR == LIMIT and LIMIT is another
1576 SSA name, the new range will also inherit the equivalence set
1578 if (TREE_CODE (limit) == SSA_NAME)
1579 add_equivalence (&vr_p->equiv, limit);
1581 else if (cond_code == NE_EXPR)
1583 /* As described above, when LIMIT's range is an anti-range and
1584 this assertion is an inequality (NE_EXPR), then we cannot
1585 derive anything from the anti-range. For instance, if
1586 LIMIT's range was ~[0, 0], the assertion 'VAR != LIMIT' does
1587 not imply that VAR's range is [0, 0]. So, in the case of
1588 anti-ranges, we just assert the inequality using LIMIT and
1591 If LIMIT_VR is a range, we can only use it to build a new
1592 anti-range if LIMIT_VR is a single-valued range. For
1593 instance, if LIMIT_VR is [0, 1], the predicate
1594 VAR != [0, 1] does not mean that VAR's range is ~[0, 1].
1595 Rather, it means that for value 0 VAR should be ~[0, 0]
1596 and for value 1, VAR should be ~[1, 1]. We cannot
1597 represent these ranges.
1599 The only situation in which we can build a valid
1600 anti-range is when LIMIT_VR is a single-valued range
1601 (i.e., LIMIT_VR->MIN == LIMIT_VR->MAX). In that case,
1602 build the anti-range ~[LIMIT_VR->MIN, LIMIT_VR->MAX]. */
1604 && limit_vr->type == VR_RANGE
1605 && compare_values (limit_vr->min, limit_vr->max) == 0)
1607 min = limit_vr->min;
1608 max = limit_vr->max;
1612 /* In any other case, we cannot use LIMIT's range to build a
1613 valid anti-range. */
1617 /* If MIN and MAX cover the whole range for their type, then
1618 just use the original LIMIT. */
1619 if (INTEGRAL_TYPE_P (type)
1620 && vrp_val_is_min (min)
1621 && vrp_val_is_max (max))
1624 set_value_range (vr_p, VR_ANTI_RANGE, min, max, vr_p->equiv);
1626 else if (cond_code == LE_EXPR || cond_code == LT_EXPR)
1628 min = TYPE_MIN_VALUE (type);
1630 if (limit_vr == NULL || limit_vr->type == VR_ANTI_RANGE)
1634 /* If LIMIT_VR is of the form [N1, N2], we need to build the
1635 range [MIN, N2] for LE_EXPR and [MIN, N2 - 1] for
1637 max = limit_vr->max;
1640 /* If the maximum value forces us to be out of bounds, simply punt.
1641 It would be pointless to try and do anything more since this
1642 all should be optimized away above us. */
1643 if ((cond_code == LT_EXPR
1644 && compare_values (max, min) == 0)
1645 || (CONSTANT_CLASS_P (max) && TREE_OVERFLOW (max)))
1646 set_value_range_to_varying (vr_p);
1649 /* For LT_EXPR, we create the range [MIN, MAX - 1]. */
1650 if (cond_code == LT_EXPR)
1652 tree one = build_int_cst (type, 1);
1653 max = fold_build2 (MINUS_EXPR, type, max, one);
1655 TREE_NO_WARNING (max) = 1;
1658 set_value_range (vr_p, VR_RANGE, min, max, vr_p->equiv);
1661 else if (cond_code == GE_EXPR || cond_code == GT_EXPR)
1663 max = TYPE_MAX_VALUE (type);
1665 if (limit_vr == NULL || limit_vr->type == VR_ANTI_RANGE)
1669 /* If LIMIT_VR is of the form [N1, N2], we need to build the
1670 range [N1, MAX] for GE_EXPR and [N1 + 1, MAX] for
1672 min = limit_vr->min;
1675 /* If the minimum value forces us to be out of bounds, simply punt.
1676 It would be pointless to try and do anything more since this
1677 all should be optimized away above us. */
1678 if ((cond_code == GT_EXPR
1679 && compare_values (min, max) == 0)
1680 || (CONSTANT_CLASS_P (min) && TREE_OVERFLOW (min)))
1681 set_value_range_to_varying (vr_p);
1684 /* For GT_EXPR, we create the range [MIN + 1, MAX]. */
1685 if (cond_code == GT_EXPR)
1687 tree one = build_int_cst (type, 1);
1688 min = fold_build2 (PLUS_EXPR, type, min, one);
1690 TREE_NO_WARNING (min) = 1;
1693 set_value_range (vr_p, VR_RANGE, min, max, vr_p->equiv);
1699 /* If VAR already had a known range, it may happen that the new
1700 range we have computed and VAR's range are not compatible. For
1704 p_6 = ASSERT_EXPR <p_5, p_5 == NULL>;
1706 p_8 = ASSERT_EXPR <p_6, p_6 != NULL>;
1708 While the above comes from a faulty program, it will cause an ICE
1709 later because p_8 and p_6 will have incompatible ranges and at
1710 the same time will be considered equivalent. A similar situation
1714 i_6 = ASSERT_EXPR <i_5, i_5 > 10>;
1716 i_7 = ASSERT_EXPR <i_6, i_6 < 5>;
1718 Again i_6 and i_7 will have incompatible ranges. It would be
1719 pointless to try and do anything with i_7's range because
1720 anything dominated by 'if (i_5 < 5)' will be optimized away.
1721 Note, due to the wa in which simulation proceeds, the statement
1722 i_7 = ASSERT_EXPR <...> we would never be visited because the
1723 conditional 'if (i_5 < 5)' always evaluates to false. However,
1724 this extra check does not hurt and may protect against future
1725 changes to VRP that may get into a situation similar to the
1726 NULL pointer dereference example.
1728 Note that these compatibility tests are only needed when dealing
1729 with ranges or a mix of range and anti-range. If VAR_VR and VR_P
1730 are both anti-ranges, they will always be compatible, because two
1731 anti-ranges will always have a non-empty intersection. */
1733 var_vr = get_value_range (var);
1735 /* We may need to make adjustments when VR_P and VAR_VR are numeric
1736 ranges or anti-ranges. */
1737 if (vr_p->type == VR_VARYING
1738 || vr_p->type == VR_UNDEFINED
1739 || var_vr->type == VR_VARYING
1740 || var_vr->type == VR_UNDEFINED
1741 || symbolic_range_p (vr_p)
1742 || symbolic_range_p (var_vr))
1745 if (var_vr->type == VR_RANGE && vr_p->type == VR_RANGE)
1747 /* If the two ranges have a non-empty intersection, we can
1748 refine the resulting range. Since the assert expression
1749 creates an equivalency and at the same time it asserts a
1750 predicate, we can take the intersection of the two ranges to
1751 get better precision. */
1752 if (value_ranges_intersect_p (var_vr, vr_p))
1754 /* Use the larger of the two minimums. */
1755 if (compare_values (vr_p->min, var_vr->min) == -1)
1760 /* Use the smaller of the two maximums. */
1761 if (compare_values (vr_p->max, var_vr->max) == 1)
1766 set_value_range (vr_p, vr_p->type, min, max, vr_p->equiv);
1770 /* The two ranges do not intersect, set the new range to
1771 VARYING, because we will not be able to do anything
1772 meaningful with it. */
1773 set_value_range_to_varying (vr_p);
1776 else if ((var_vr->type == VR_RANGE && vr_p->type == VR_ANTI_RANGE)
1777 || (var_vr->type == VR_ANTI_RANGE && vr_p->type == VR_RANGE))
1779 /* A range and an anti-range will cancel each other only if
1780 their ends are the same. For instance, in the example above,
1781 p_8's range ~[0, 0] and p_6's range [0, 0] are incompatible,
1782 so VR_P should be set to VR_VARYING. */
1783 if (compare_values (var_vr->min, vr_p->min) == 0
1784 && compare_values (var_vr->max, vr_p->max) == 0)
1785 set_value_range_to_varying (vr_p);
1788 tree min, max, anti_min, anti_max, real_min, real_max;
1791 /* We want to compute the logical AND of the two ranges;
1792 there are three cases to consider.
1795 1. The VR_ANTI_RANGE range is completely within the
1796 VR_RANGE and the endpoints of the ranges are
1797 different. In that case the resulting range
1798 should be whichever range is more precise.
1799 Typically that will be the VR_RANGE.
1801 2. The VR_ANTI_RANGE is completely disjoint from
1802 the VR_RANGE. In this case the resulting range
1803 should be the VR_RANGE.
1805 3. There is some overlap between the VR_ANTI_RANGE
1808 3a. If the high limit of the VR_ANTI_RANGE resides
1809 within the VR_RANGE, then the result is a new
1810 VR_RANGE starting at the high limit of the
1811 VR_ANTI_RANGE + 1 and extending to the
1812 high limit of the original VR_RANGE.
1814 3b. If the low limit of the VR_ANTI_RANGE resides
1815 within the VR_RANGE, then the result is a new
1816 VR_RANGE starting at the low limit of the original
1817 VR_RANGE and extending to the low limit of the
1818 VR_ANTI_RANGE - 1. */
1819 if (vr_p->type == VR_ANTI_RANGE)
1821 anti_min = vr_p->min;
1822 anti_max = vr_p->max;
1823 real_min = var_vr->min;
1824 real_max = var_vr->max;
1828 anti_min = var_vr->min;
1829 anti_max = var_vr->max;
1830 real_min = vr_p->min;
1831 real_max = vr_p->max;
1835 /* Case 1, VR_ANTI_RANGE completely within VR_RANGE,
1836 not including any endpoints. */
1837 if (compare_values (anti_max, real_max) == -1
1838 && compare_values (anti_min, real_min) == 1)
1840 /* If the range is covering the whole valid range of
1841 the type keep the anti-range. */
1842 if (!vrp_val_is_min (real_min)
1843 || !vrp_val_is_max (real_max))
1844 set_value_range (vr_p, VR_RANGE, real_min,
1845 real_max, vr_p->equiv);
1847 /* Case 2, VR_ANTI_RANGE completely disjoint from
1849 else if (compare_values (anti_min, real_max) == 1
1850 || compare_values (anti_max, real_min) == -1)
1852 set_value_range (vr_p, VR_RANGE, real_min,
1853 real_max, vr_p->equiv);
1855 /* Case 3a, the anti-range extends into the low
1856 part of the real range. Thus creating a new
1857 low for the real range. */
1858 else if (((cmp = compare_values (anti_max, real_min)) == 1
1860 && compare_values (anti_max, real_max) == -1)
1862 gcc_assert (!is_positive_overflow_infinity (anti_max));
1863 if (needs_overflow_infinity (TREE_TYPE (anti_max))
1864 && vrp_val_is_max (anti_max))
1866 if (!supports_overflow_infinity (TREE_TYPE (var_vr->min)))
1868 set_value_range_to_varying (vr_p);
1871 min = positive_overflow_infinity (TREE_TYPE (var_vr->min));
1873 else if (!POINTER_TYPE_P (TREE_TYPE (var_vr->min)))
1874 min = fold_build2 (PLUS_EXPR, TREE_TYPE (var_vr->min),
1876 build_int_cst (TREE_TYPE (var_vr->min), 1));
1878 min = fold_build2 (POINTER_PLUS_EXPR, TREE_TYPE (var_vr->min),
1879 anti_max, size_int (1));
1881 set_value_range (vr_p, VR_RANGE, min, max, vr_p->equiv);
1883 /* Case 3b, the anti-range extends into the high
1884 part of the real range. Thus creating a new
1885 higher for the real range. */
1886 else if (compare_values (anti_min, real_min) == 1
1887 && ((cmp = compare_values (anti_min, real_max)) == -1
1890 gcc_assert (!is_negative_overflow_infinity (anti_min));
1891 if (needs_overflow_infinity (TREE_TYPE (anti_min))
1892 && vrp_val_is_min (anti_min))
1894 if (!supports_overflow_infinity (TREE_TYPE (var_vr->min)))
1896 set_value_range_to_varying (vr_p);
1899 max = negative_overflow_infinity (TREE_TYPE (var_vr->min));
1901 else if (!POINTER_TYPE_P (TREE_TYPE (var_vr->min)))
1902 max = fold_build2 (MINUS_EXPR, TREE_TYPE (var_vr->min),
1904 build_int_cst (TREE_TYPE (var_vr->min), 1));
1906 max = fold_build2 (POINTER_PLUS_EXPR, TREE_TYPE (var_vr->min),
1910 set_value_range (vr_p, VR_RANGE, min, max, vr_p->equiv);
1917 /* Extract range information from SSA name VAR and store it in VR. If
1918 VAR has an interesting range, use it. Otherwise, create the
1919 range [VAR, VAR] and return it. This is useful in situations where
1920 we may have conditionals testing values of VARYING names. For
1927 Even if y_5 is deemed VARYING, we can determine that x_3 > y_5 is
1931 extract_range_from_ssa_name (value_range_t *vr, tree var)
1933 value_range_t *var_vr = get_value_range (var);
1935 if (var_vr->type != VR_UNDEFINED && var_vr->type != VR_VARYING)
1936 copy_value_range (vr, var_vr);
1938 set_value_range (vr, VR_RANGE, var, var, NULL);
1940 add_equivalence (&vr->equiv, var);
1944 /* Wrapper around int_const_binop. If the operation overflows and we
1945 are not using wrapping arithmetic, then adjust the result to be
1946 -INF or +INF depending on CODE, VAL1 and VAL2. This can return
1947 NULL_TREE if we need to use an overflow infinity representation but
1948 the type does not support it. */
1951 vrp_int_const_binop (enum tree_code code, tree val1, tree val2)
1955 res = int_const_binop (code, val1, val2, 0);
1957 /* If we are using unsigned arithmetic, operate symbolically
1958 on -INF and +INF as int_const_binop only handles signed overflow. */
1959 if (TYPE_UNSIGNED (TREE_TYPE (val1)))
1961 int checkz = compare_values (res, val1);
1962 bool overflow = false;
1964 /* Ensure that res = val1 [+*] val2 >= val1
1965 or that res = val1 - val2 <= val1. */
1966 if ((code == PLUS_EXPR
1967 && !(checkz == 1 || checkz == 0))
1968 || (code == MINUS_EXPR
1969 && !(checkz == 0 || checkz == -1)))
1973 /* Checking for multiplication overflow is done by dividing the
1974 output of the multiplication by the first input of the
1975 multiplication. If the result of that division operation is
1976 not equal to the second input of the multiplication, then the
1977 multiplication overflowed. */
1978 else if (code == MULT_EXPR && !integer_zerop (val1))
1980 tree tmp = int_const_binop (TRUNC_DIV_EXPR,
1983 int check = compare_values (tmp, val2);
1991 res = copy_node (res);
1992 TREE_OVERFLOW (res) = 1;
1996 else if (TYPE_OVERFLOW_WRAPS (TREE_TYPE (val1)))
1997 /* If the singed operation wraps then int_const_binop has done
1998 everything we want. */
2000 else if ((TREE_OVERFLOW (res)
2001 && !TREE_OVERFLOW (val1)
2002 && !TREE_OVERFLOW (val2))
2003 || is_overflow_infinity (val1)
2004 || is_overflow_infinity (val2))
2006 /* If the operation overflowed but neither VAL1 nor VAL2 are
2007 overflown, return -INF or +INF depending on the operation
2008 and the combination of signs of the operands. */
2009 int sgn1 = tree_int_cst_sgn (val1);
2010 int sgn2 = tree_int_cst_sgn (val2);
2012 if (needs_overflow_infinity (TREE_TYPE (res))
2013 && !supports_overflow_infinity (TREE_TYPE (res)))
2016 /* We have to punt on adding infinities of different signs,
2017 since we can't tell what the sign of the result should be.
2018 Likewise for subtracting infinities of the same sign. */
2019 if (((code == PLUS_EXPR && sgn1 != sgn2)
2020 || (code == MINUS_EXPR && sgn1 == sgn2))
2021 && is_overflow_infinity (val1)
2022 && is_overflow_infinity (val2))
2025 /* Don't try to handle division or shifting of infinities. */
2026 if ((code == TRUNC_DIV_EXPR
2027 || code == FLOOR_DIV_EXPR
2028 || code == CEIL_DIV_EXPR
2029 || code == EXACT_DIV_EXPR
2030 || code == ROUND_DIV_EXPR
2031 || code == RSHIFT_EXPR)
2032 && (is_overflow_infinity (val1)
2033 || is_overflow_infinity (val2)))
2036 /* Notice that we only need to handle the restricted set of
2037 operations handled by extract_range_from_binary_expr.
2038 Among them, only multiplication, addition and subtraction
2039 can yield overflow without overflown operands because we
2040 are working with integral types only... except in the
2041 case VAL1 = -INF and VAL2 = -1 which overflows to +INF
2042 for division too. */
2044 /* For multiplication, the sign of the overflow is given
2045 by the comparison of the signs of the operands. */
2046 if ((code == MULT_EXPR && sgn1 == sgn2)
2047 /* For addition, the operands must be of the same sign
2048 to yield an overflow. Its sign is therefore that
2049 of one of the operands, for example the first. For
2050 infinite operands X + -INF is negative, not positive. */
2051 || (code == PLUS_EXPR
2053 ? !is_negative_overflow_infinity (val2)
2054 : is_positive_overflow_infinity (val2)))
2055 /* For subtraction, non-infinite operands must be of
2056 different signs to yield an overflow. Its sign is
2057 therefore that of the first operand or the opposite of
2058 that of the second operand. A first operand of 0 counts
2059 as positive here, for the corner case 0 - (-INF), which
2060 overflows, but must yield +INF. For infinite operands 0
2061 - INF is negative, not positive. */
2062 || (code == MINUS_EXPR
2064 ? !is_positive_overflow_infinity (val2)
2065 : is_negative_overflow_infinity (val2)))
2066 /* We only get in here with positive shift count, so the
2067 overflow direction is the same as the sign of val1.
2068 Actually rshift does not overflow at all, but we only
2069 handle the case of shifting overflowed -INF and +INF. */
2070 || (code == RSHIFT_EXPR
2072 /* For division, the only case is -INF / -1 = +INF. */
2073 || code == TRUNC_DIV_EXPR
2074 || code == FLOOR_DIV_EXPR
2075 || code == CEIL_DIV_EXPR
2076 || code == EXACT_DIV_EXPR
2077 || code == ROUND_DIV_EXPR)
2078 return (needs_overflow_infinity (TREE_TYPE (res))
2079 ? positive_overflow_infinity (TREE_TYPE (res))
2080 : TYPE_MAX_VALUE (TREE_TYPE (res)));
2082 return (needs_overflow_infinity (TREE_TYPE (res))
2083 ? negative_overflow_infinity (TREE_TYPE (res))
2084 : TYPE_MIN_VALUE (TREE_TYPE (res)));
2091 /* For range VR compute two double_int bitmasks. In *MAY_BE_NONZERO
2092 bitmask if some bit is unset, it means for all numbers in the range
2093 the bit is 0, otherwise it might be 0 or 1. In *MUST_BE_NONZERO
2094 bitmask if some bit is set, it means for all numbers in the range
2095 the bit is 1, otherwise it might be 0 or 1. */
2098 zero_nonzero_bits_from_vr (value_range_t *vr, double_int *may_be_nonzero,
2099 double_int *must_be_nonzero)
2101 if (range_int_cst_p (vr))
2103 if (range_int_cst_singleton_p (vr))
2105 *may_be_nonzero = tree_to_double_int (vr->min);
2106 *must_be_nonzero = *may_be_nonzero;
2109 if (tree_int_cst_sgn (vr->min) >= 0)
2111 double_int dmin = tree_to_double_int (vr->min);
2112 double_int dmax = tree_to_double_int (vr->max);
2113 double_int xor_mask = double_int_xor (dmin, dmax);
2114 *may_be_nonzero = double_int_ior (dmin, dmax);
2115 *must_be_nonzero = double_int_and (dmin, dmax);
2116 if (xor_mask.high != 0)
2118 unsigned HOST_WIDE_INT mask
2119 = ((unsigned HOST_WIDE_INT) 1
2120 << floor_log2 (xor_mask.high)) - 1;
2121 may_be_nonzero->low = ALL_ONES;
2122 may_be_nonzero->high |= mask;
2123 must_be_nonzero->low = 0;
2124 must_be_nonzero->high &= ~mask;
2126 else if (xor_mask.low != 0)
2128 unsigned HOST_WIDE_INT mask
2129 = ((unsigned HOST_WIDE_INT) 1
2130 << floor_log2 (xor_mask.low)) - 1;
2131 may_be_nonzero->low |= mask;
2132 must_be_nonzero->low &= ~mask;
2137 may_be_nonzero->low = ALL_ONES;
2138 may_be_nonzero->high = ALL_ONES;
2139 must_be_nonzero->low = 0;
2140 must_be_nonzero->high = 0;
2145 /* Extract range information from a binary expression EXPR based on
2146 the ranges of each of its operands and the expression code. */
2149 extract_range_from_binary_expr (value_range_t *vr,
2150 enum tree_code code,
2151 tree expr_type, tree op0, tree op1)
2153 enum value_range_type type;
2156 value_range_t vr0 = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
2157 value_range_t vr1 = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
2159 /* Not all binary expressions can be applied to ranges in a
2160 meaningful way. Handle only arithmetic operations. */
2161 if (code != PLUS_EXPR
2162 && code != MINUS_EXPR
2163 && code != POINTER_PLUS_EXPR
2164 && code != MULT_EXPR
2165 && code != TRUNC_DIV_EXPR
2166 && code != FLOOR_DIV_EXPR
2167 && code != CEIL_DIV_EXPR
2168 && code != EXACT_DIV_EXPR
2169 && code != ROUND_DIV_EXPR
2170 && code != TRUNC_MOD_EXPR
2171 && code != RSHIFT_EXPR
2174 && code != BIT_AND_EXPR
2175 && code != BIT_IOR_EXPR
2176 && code != TRUTH_AND_EXPR
2177 && code != TRUTH_OR_EXPR)
2179 /* We can still do constant propagation here. */
2180 tree const_op0 = op_with_constant_singleton_value_range (op0);
2181 tree const_op1 = op_with_constant_singleton_value_range (op1);
2182 if (const_op0 || const_op1)
2184 tree tem = fold_binary (code, expr_type,
2185 const_op0 ? const_op0 : op0,
2186 const_op1 ? const_op1 : op1);
2188 && is_gimple_min_invariant (tem)
2189 && !is_overflow_infinity (tem))
2191 set_value_range (vr, VR_RANGE, tem, tem, NULL);
2195 set_value_range_to_varying (vr);
2199 /* Get value ranges for each operand. For constant operands, create
2200 a new value range with the operand to simplify processing. */
2201 if (TREE_CODE (op0) == SSA_NAME)
2202 vr0 = *(get_value_range (op0));
2203 else if (is_gimple_min_invariant (op0))
2204 set_value_range_to_value (&vr0, op0, NULL);
2206 set_value_range_to_varying (&vr0);
2208 if (TREE_CODE (op1) == SSA_NAME)
2209 vr1 = *(get_value_range (op1));
2210 else if (is_gimple_min_invariant (op1))
2211 set_value_range_to_value (&vr1, op1, NULL);
2213 set_value_range_to_varying (&vr1);
2215 /* If either range is UNDEFINED, so is the result. */
2216 if (vr0.type == VR_UNDEFINED || vr1.type == VR_UNDEFINED)
2218 set_value_range_to_undefined (vr);
2222 /* The type of the resulting value range defaults to VR0.TYPE. */
2225 /* Refuse to operate on VARYING ranges, ranges of different kinds
2226 and symbolic ranges. As an exception, we allow BIT_AND_EXPR
2227 because we may be able to derive a useful range even if one of
2228 the operands is VR_VARYING or symbolic range. Similarly for
2229 divisions. TODO, we may be able to derive anti-ranges in
2231 if (code != BIT_AND_EXPR
2232 && code != TRUTH_AND_EXPR
2233 && code != TRUTH_OR_EXPR
2234 && code != TRUNC_DIV_EXPR
2235 && code != FLOOR_DIV_EXPR
2236 && code != CEIL_DIV_EXPR
2237 && code != EXACT_DIV_EXPR
2238 && code != ROUND_DIV_EXPR
2239 && code != TRUNC_MOD_EXPR
2240 && (vr0.type == VR_VARYING
2241 || vr1.type == VR_VARYING
2242 || vr0.type != vr1.type
2243 || symbolic_range_p (&vr0)
2244 || symbolic_range_p (&vr1)))
2246 set_value_range_to_varying (vr);
2250 /* Now evaluate the expression to determine the new range. */
2251 if (POINTER_TYPE_P (expr_type)
2252 || POINTER_TYPE_P (TREE_TYPE (op0))
2253 || POINTER_TYPE_P (TREE_TYPE (op1)))
2255 if (code == MIN_EXPR || code == MAX_EXPR)
2257 /* For MIN/MAX expressions with pointers, we only care about
2258 nullness, if both are non null, then the result is nonnull.
2259 If both are null, then the result is null. Otherwise they
2261 if (range_is_nonnull (&vr0) && range_is_nonnull (&vr1))
2262 set_value_range_to_nonnull (vr, expr_type);
2263 else if (range_is_null (&vr0) && range_is_null (&vr1))
2264 set_value_range_to_null (vr, expr_type);
2266 set_value_range_to_varying (vr);
2270 if (code == POINTER_PLUS_EXPR)
2272 /* For pointer types, we are really only interested in asserting
2273 whether the expression evaluates to non-NULL. */
2274 if (range_is_nonnull (&vr0) || range_is_nonnull (&vr1))
2275 set_value_range_to_nonnull (vr, expr_type);
2276 else if (range_is_null (&vr0) && range_is_null (&vr1))
2277 set_value_range_to_null (vr, expr_type);
2279 set_value_range_to_varying (vr);
2281 else if (code == BIT_AND_EXPR)
2283 /* For pointer types, we are really only interested in asserting
2284 whether the expression evaluates to non-NULL. */
2285 if (range_is_nonnull (&vr0) && range_is_nonnull (&vr1))
2286 set_value_range_to_nonnull (vr, expr_type);
2287 else if (range_is_null (&vr0) || range_is_null (&vr1))
2288 set_value_range_to_null (vr, expr_type);
2290 set_value_range_to_varying (vr);
2298 /* For integer ranges, apply the operation to each end of the
2299 range and see what we end up with. */
2300 if (code == TRUTH_AND_EXPR
2301 || code == TRUTH_OR_EXPR)
2303 /* If one of the operands is zero, we know that the whole
2304 expression evaluates zero. */
2305 if (code == TRUTH_AND_EXPR
2306 && ((vr0.type == VR_RANGE
2307 && integer_zerop (vr0.min)
2308 && integer_zerop (vr0.max))
2309 || (vr1.type == VR_RANGE
2310 && integer_zerop (vr1.min)
2311 && integer_zerop (vr1.max))))
2314 min = max = build_int_cst (expr_type, 0);
2316 /* If one of the operands is one, we know that the whole
2317 expression evaluates one. */
2318 else if (code == TRUTH_OR_EXPR
2319 && ((vr0.type == VR_RANGE
2320 && integer_onep (vr0.min)
2321 && integer_onep (vr0.max))
2322 || (vr1.type == VR_RANGE
2323 && integer_onep (vr1.min)
2324 && integer_onep (vr1.max))))
2327 min = max = build_int_cst (expr_type, 1);
2329 else if (vr0.type != VR_VARYING
2330 && vr1.type != VR_VARYING
2331 && vr0.type == vr1.type
2332 && !symbolic_range_p (&vr0)
2333 && !overflow_infinity_range_p (&vr0)
2334 && !symbolic_range_p (&vr1)
2335 && !overflow_infinity_range_p (&vr1))
2337 /* Boolean expressions cannot be folded with int_const_binop. */
2338 min = fold_binary (code, expr_type, vr0.min, vr1.min);
2339 max = fold_binary (code, expr_type, vr0.max, vr1.max);
2343 /* The result of a TRUTH_*_EXPR is always true or false. */
2344 set_value_range_to_truthvalue (vr, expr_type);
2348 else if (code == PLUS_EXPR
2350 || code == MAX_EXPR)
2352 /* If we have a PLUS_EXPR with two VR_ANTI_RANGEs, drop to
2353 VR_VARYING. It would take more effort to compute a precise
2354 range for such a case. For example, if we have op0 == 1 and
2355 op1 == -1 with their ranges both being ~[0,0], we would have
2356 op0 + op1 == 0, so we cannot claim that the sum is in ~[0,0].
2357 Note that we are guaranteed to have vr0.type == vr1.type at
2359 if (code == PLUS_EXPR && vr0.type == VR_ANTI_RANGE)
2361 set_value_range_to_varying (vr);
2365 /* For operations that make the resulting range directly
2366 proportional to the original ranges, apply the operation to
2367 the same end of each range. */
2368 min = vrp_int_const_binop (code, vr0.min, vr1.min);
2369 max = vrp_int_const_binop (code, vr0.max, vr1.max);
2371 /* If both additions overflowed the range kind is still correct.
2372 This happens regularly with subtracting something in unsigned
2374 ??? See PR30318 for all the cases we do not handle. */
2375 if (code == PLUS_EXPR
2376 && (TREE_OVERFLOW (min) && !is_overflow_infinity (min))
2377 && (TREE_OVERFLOW (max) && !is_overflow_infinity (max)))
2379 min = build_int_cst_wide (TREE_TYPE (min),
2380 TREE_INT_CST_LOW (min),
2381 TREE_INT_CST_HIGH (min));
2382 max = build_int_cst_wide (TREE_TYPE (max),
2383 TREE_INT_CST_LOW (max),
2384 TREE_INT_CST_HIGH (max));
2387 else if (code == MULT_EXPR
2388 || code == TRUNC_DIV_EXPR
2389 || code == FLOOR_DIV_EXPR
2390 || code == CEIL_DIV_EXPR
2391 || code == EXACT_DIV_EXPR
2392 || code == ROUND_DIV_EXPR
2393 || code == RSHIFT_EXPR)
2399 /* If we have an unsigned MULT_EXPR with two VR_ANTI_RANGEs,
2400 drop to VR_VARYING. It would take more effort to compute a
2401 precise range for such a case. For example, if we have
2402 op0 == 65536 and op1 == 65536 with their ranges both being
2403 ~[0,0] on a 32-bit machine, we would have op0 * op1 == 0, so
2404 we cannot claim that the product is in ~[0,0]. Note that we
2405 are guaranteed to have vr0.type == vr1.type at this
2407 if (code == MULT_EXPR
2408 && vr0.type == VR_ANTI_RANGE
2409 && !TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (op0)))
2411 set_value_range_to_varying (vr);
2415 /* If we have a RSHIFT_EXPR with any shift values outside [0..prec-1],
2416 then drop to VR_VARYING. Outside of this range we get undefined
2417 behavior from the shift operation. We cannot even trust
2418 SHIFT_COUNT_TRUNCATED at this stage, because that applies to rtl
2419 shifts, and the operation at the tree level may be widened. */
2420 if (code == RSHIFT_EXPR)
2422 if (vr1.type == VR_ANTI_RANGE
2423 || !vrp_expr_computes_nonnegative (op1, &sop)
2425 (build_int_cst (TREE_TYPE (vr1.max),
2426 TYPE_PRECISION (expr_type) - 1),
2429 set_value_range_to_varying (vr);
2434 else if ((code == TRUNC_DIV_EXPR
2435 || code == FLOOR_DIV_EXPR
2436 || code == CEIL_DIV_EXPR
2437 || code == EXACT_DIV_EXPR
2438 || code == ROUND_DIV_EXPR)
2439 && (vr0.type != VR_RANGE || symbolic_range_p (&vr0)))
2441 /* For division, if op1 has VR_RANGE but op0 does not, something
2442 can be deduced just from that range. Say [min, max] / [4, max]
2443 gives [min / 4, max / 4] range. */
2444 if (vr1.type == VR_RANGE
2445 && !symbolic_range_p (&vr1)
2446 && !range_includes_zero_p (&vr1))
2448 vr0.type = type = VR_RANGE;
2449 vr0.min = vrp_val_min (TREE_TYPE (op0));
2450 vr0.max = vrp_val_max (TREE_TYPE (op1));
2454 set_value_range_to_varying (vr);
2459 /* For divisions, if flag_non_call_exceptions is true, we must
2460 not eliminate a division by zero. */
2461 if ((code == TRUNC_DIV_EXPR
2462 || code == FLOOR_DIV_EXPR
2463 || code == CEIL_DIV_EXPR
2464 || code == EXACT_DIV_EXPR
2465 || code == ROUND_DIV_EXPR)
2466 && cfun->can_throw_non_call_exceptions
2467 && (vr1.type != VR_RANGE
2468 || symbolic_range_p (&vr1)
2469 || range_includes_zero_p (&vr1)))
2471 set_value_range_to_varying (vr);
2475 /* For divisions, if op0 is VR_RANGE, we can deduce a range
2476 even if op1 is VR_VARYING, VR_ANTI_RANGE, symbolic or can
2478 if ((code == TRUNC_DIV_EXPR
2479 || code == FLOOR_DIV_EXPR
2480 || code == CEIL_DIV_EXPR
2481 || code == EXACT_DIV_EXPR
2482 || code == ROUND_DIV_EXPR)
2483 && vr0.type == VR_RANGE
2484 && (vr1.type != VR_RANGE
2485 || symbolic_range_p (&vr1)
2486 || range_includes_zero_p (&vr1)))
2488 tree zero = build_int_cst (TREE_TYPE (vr0.min), 0);
2494 if (vrp_expr_computes_nonnegative (op1, &sop) && !sop)
2496 /* For unsigned division or when divisor is known
2497 to be non-negative, the range has to cover
2498 all numbers from 0 to max for positive max
2499 and all numbers from min to 0 for negative min. */
2500 cmp = compare_values (vr0.max, zero);
2503 else if (cmp == 0 || cmp == 1)
2507 cmp = compare_values (vr0.min, zero);
2510 else if (cmp == 0 || cmp == -1)
2517 /* Otherwise the range is -max .. max or min .. -min
2518 depending on which bound is bigger in absolute value,
2519 as the division can change the sign. */
2520 abs_extent_range (vr, vr0.min, vr0.max);
2523 if (type == VR_VARYING)
2525 set_value_range_to_varying (vr);
2530 /* Multiplications and divisions are a bit tricky to handle,
2531 depending on the mix of signs we have in the two ranges, we
2532 need to operate on different values to get the minimum and
2533 maximum values for the new range. One approach is to figure
2534 out all the variations of range combinations and do the
2537 However, this involves several calls to compare_values and it
2538 is pretty convoluted. It's simpler to do the 4 operations
2539 (MIN0 OP MIN1, MIN0 OP MAX1, MAX0 OP MIN1 and MAX0 OP MAX0 OP
2540 MAX1) and then figure the smallest and largest values to form
2544 gcc_assert ((vr0.type == VR_RANGE
2545 || (code == MULT_EXPR && vr0.type == VR_ANTI_RANGE))
2546 && vr0.type == vr1.type);
2548 /* Compute the 4 cross operations. */
2550 val[0] = vrp_int_const_binop (code, vr0.min, vr1.min);
2551 if (val[0] == NULL_TREE)
2554 if (vr1.max == vr1.min)
2558 val[1] = vrp_int_const_binop (code, vr0.min, vr1.max);
2559 if (val[1] == NULL_TREE)
2563 if (vr0.max == vr0.min)
2567 val[2] = vrp_int_const_binop (code, vr0.max, vr1.min);
2568 if (val[2] == NULL_TREE)
2572 if (vr0.min == vr0.max || vr1.min == vr1.max)
2576 val[3] = vrp_int_const_binop (code, vr0.max, vr1.max);
2577 if (val[3] == NULL_TREE)
2583 set_value_range_to_varying (vr);
2587 /* Set MIN to the minimum of VAL[i] and MAX to the maximum
2591 for (i = 1; i < 4; i++)
2593 if (!is_gimple_min_invariant (min)
2594 || (TREE_OVERFLOW (min) && !is_overflow_infinity (min))
2595 || !is_gimple_min_invariant (max)
2596 || (TREE_OVERFLOW (max) && !is_overflow_infinity (max)))
2601 if (!is_gimple_min_invariant (val[i])
2602 || (TREE_OVERFLOW (val[i])
2603 && !is_overflow_infinity (val[i])))
2605 /* If we found an overflowed value, set MIN and MAX
2606 to it so that we set the resulting range to
2612 if (compare_values (val[i], min) == -1)
2615 if (compare_values (val[i], max) == 1)
2621 else if (code == TRUNC_MOD_EXPR)
2624 if (vr1.type != VR_RANGE
2625 || symbolic_range_p (&vr1)
2626 || range_includes_zero_p (&vr1)
2627 || vrp_val_is_min (vr1.min))
2629 set_value_range_to_varying (vr);
2633 /* Compute MAX <|vr1.min|, |vr1.max|> - 1. */
2634 max = fold_unary_to_constant (ABS_EXPR, TREE_TYPE (vr1.min), vr1.min);
2635 if (tree_int_cst_lt (max, vr1.max))
2637 max = int_const_binop (MINUS_EXPR, max, integer_one_node, 0);
2638 /* If the dividend is non-negative the modulus will be
2639 non-negative as well. */
2640 if (TYPE_UNSIGNED (TREE_TYPE (max))
2641 || (vrp_expr_computes_nonnegative (op0, &sop) && !sop))
2642 min = build_int_cst (TREE_TYPE (max), 0);
2644 min = fold_unary_to_constant (NEGATE_EXPR, TREE_TYPE (max), max);
2646 else if (code == MINUS_EXPR)
2648 /* If we have a MINUS_EXPR with two VR_ANTI_RANGEs, drop to
2649 VR_VARYING. It would take more effort to compute a precise
2650 range for such a case. For example, if we have op0 == 1 and
2651 op1 == 1 with their ranges both being ~[0,0], we would have
2652 op0 - op1 == 0, so we cannot claim that the difference is in
2653 ~[0,0]. Note that we are guaranteed to have
2654 vr0.type == vr1.type at this point. */
2655 if (vr0.type == VR_ANTI_RANGE)
2657 set_value_range_to_varying (vr);
2661 /* For MINUS_EXPR, apply the operation to the opposite ends of
2663 min = vrp_int_const_binop (code, vr0.min, vr1.max);
2664 max = vrp_int_const_binop (code, vr0.max, vr1.min);
2666 else if (code == BIT_AND_EXPR || code == BIT_IOR_EXPR)
2668 bool vr0_int_cst_singleton_p, vr1_int_cst_singleton_p;
2669 bool int_cst_range0, int_cst_range1;
2670 double_int may_be_nonzero0, may_be_nonzero1;
2671 double_int must_be_nonzero0, must_be_nonzero1;
2673 vr0_int_cst_singleton_p = range_int_cst_singleton_p (&vr0);
2674 vr1_int_cst_singleton_p = range_int_cst_singleton_p (&vr1);
2675 int_cst_range0 = zero_nonzero_bits_from_vr (&vr0, &may_be_nonzero0,
2677 int_cst_range1 = zero_nonzero_bits_from_vr (&vr1, &may_be_nonzero1,
2681 if (vr0_int_cst_singleton_p && vr1_int_cst_singleton_p)
2682 min = max = int_const_binop (code, vr0.max, vr1.max, 0);
2683 else if (!int_cst_range0 && !int_cst_range1)
2685 set_value_range_to_varying (vr);
2688 else if (code == BIT_AND_EXPR)
2690 min = double_int_to_tree (expr_type,
2691 double_int_and (must_be_nonzero0,
2693 max = double_int_to_tree (expr_type,
2694 double_int_and (may_be_nonzero0,
2696 if (TREE_OVERFLOW (min) || tree_int_cst_sgn (min) < 0)
2698 if (TREE_OVERFLOW (max) || tree_int_cst_sgn (max) < 0)
2700 if (int_cst_range0 && tree_int_cst_sgn (vr0.min) >= 0)
2702 if (min == NULL_TREE)
2703 min = build_int_cst (expr_type, 0);
2704 if (max == NULL_TREE || tree_int_cst_lt (vr0.max, max))
2707 if (int_cst_range1 && tree_int_cst_sgn (vr1.min) >= 0)
2709 if (min == NULL_TREE)
2710 min = build_int_cst (expr_type, 0);
2711 if (max == NULL_TREE || tree_int_cst_lt (vr1.max, max))
2715 else if (!int_cst_range0
2717 || tree_int_cst_sgn (vr0.min) < 0
2718 || tree_int_cst_sgn (vr1.min) < 0)
2720 set_value_range_to_varying (vr);
2725 min = double_int_to_tree (expr_type,
2726 double_int_ior (must_be_nonzero0,
2728 max = double_int_to_tree (expr_type,
2729 double_int_ior (may_be_nonzero0,
2731 if (TREE_OVERFLOW (min) || tree_int_cst_sgn (min) < 0)
2734 min = vrp_int_const_binop (MAX_EXPR, min, vr0.min);
2735 if (TREE_OVERFLOW (max) || tree_int_cst_sgn (max) < 0)
2737 min = vrp_int_const_binop (MAX_EXPR, min, vr1.min);
2743 /* If either MIN or MAX overflowed, then set the resulting range to
2744 VARYING. But we do accept an overflow infinity
2746 if (min == NULL_TREE
2747 || !is_gimple_min_invariant (min)
2748 || (TREE_OVERFLOW (min) && !is_overflow_infinity (min))
2750 || !is_gimple_min_invariant (max)
2751 || (TREE_OVERFLOW (max) && !is_overflow_infinity (max)))
2753 set_value_range_to_varying (vr);
2759 2) [-INF, +-INF(OVF)]
2760 3) [+-INF(OVF), +INF]
2761 4) [+-INF(OVF), +-INF(OVF)]
2762 We learn nothing when we have INF and INF(OVF) on both sides.
2763 Note that we do accept [-INF, -INF] and [+INF, +INF] without
2765 if ((vrp_val_is_min (min) || is_overflow_infinity (min))
2766 && (vrp_val_is_max (max) || is_overflow_infinity (max)))
2768 set_value_range_to_varying (vr);
2772 cmp = compare_values (min, max);
2773 if (cmp == -2 || cmp == 1)
2775 /* If the new range has its limits swapped around (MIN > MAX),
2776 then the operation caused one of them to wrap around, mark
2777 the new range VARYING. */
2778 set_value_range_to_varying (vr);
2781 set_value_range (vr, type, min, max, NULL);
2785 /* Extract range information from a unary expression EXPR based on
2786 the range of its operand and the expression code. */
2789 extract_range_from_unary_expr (value_range_t *vr, enum tree_code code,
2790 tree type, tree op0)
2794 value_range_t vr0 = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
2796 /* Refuse to operate on certain unary expressions for which we
2797 cannot easily determine a resulting range. */
2798 if (code == FIX_TRUNC_EXPR
2799 || code == FLOAT_EXPR
2800 || code == BIT_NOT_EXPR
2801 || code == CONJ_EXPR)
2803 /* We can still do constant propagation here. */
2804 if ((op0 = op_with_constant_singleton_value_range (op0)) != NULL_TREE)
2806 tree tem = fold_unary (code, type, op0);
2808 && is_gimple_min_invariant (tem)
2809 && !is_overflow_infinity (tem))
2811 set_value_range (vr, VR_RANGE, tem, tem, NULL);
2815 set_value_range_to_varying (vr);
2819 /* Get value ranges for the operand. For constant operands, create
2820 a new value range with the operand to simplify processing. */
2821 if (TREE_CODE (op0) == SSA_NAME)
2822 vr0 = *(get_value_range (op0));
2823 else if (is_gimple_min_invariant (op0))
2824 set_value_range_to_value (&vr0, op0, NULL);
2826 set_value_range_to_varying (&vr0);
2828 /* If VR0 is UNDEFINED, so is the result. */
2829 if (vr0.type == VR_UNDEFINED)
2831 set_value_range_to_undefined (vr);
2835 /* Refuse to operate on symbolic ranges, or if neither operand is
2836 a pointer or integral type. */
2837 if ((!INTEGRAL_TYPE_P (TREE_TYPE (op0))
2838 && !POINTER_TYPE_P (TREE_TYPE (op0)))
2839 || (vr0.type != VR_VARYING
2840 && symbolic_range_p (&vr0)))
2842 set_value_range_to_varying (vr);
2846 /* If the expression involves pointers, we are only interested in
2847 determining if it evaluates to NULL [0, 0] or non-NULL (~[0, 0]). */
2848 if (POINTER_TYPE_P (type) || POINTER_TYPE_P (TREE_TYPE (op0)))
2853 if (range_is_nonnull (&vr0)
2854 || (tree_unary_nonzero_warnv_p (code, type, op0, &sop)
2856 set_value_range_to_nonnull (vr, type);
2857 else if (range_is_null (&vr0))
2858 set_value_range_to_null (vr, type);
2860 set_value_range_to_varying (vr);
2865 /* Handle unary expressions on integer ranges. */
2866 if (CONVERT_EXPR_CODE_P (code)
2867 && INTEGRAL_TYPE_P (type)
2868 && INTEGRAL_TYPE_P (TREE_TYPE (op0)))
2870 tree inner_type = TREE_TYPE (op0);
2871 tree outer_type = type;
2873 /* If VR0 is varying and we increase the type precision, assume
2874 a full range for the following transformation. */
2875 if (vr0.type == VR_VARYING
2876 && TYPE_PRECISION (inner_type) < TYPE_PRECISION (outer_type))
2878 vr0.type = VR_RANGE;
2879 vr0.min = TYPE_MIN_VALUE (inner_type);
2880 vr0.max = TYPE_MAX_VALUE (inner_type);
2883 /* If VR0 is a constant range or anti-range and the conversion is
2884 not truncating we can convert the min and max values and
2885 canonicalize the resulting range. Otherwise we can do the
2886 conversion if the size of the range is less than what the
2887 precision of the target type can represent and the range is
2888 not an anti-range. */
2889 if ((vr0.type == VR_RANGE
2890 || vr0.type == VR_ANTI_RANGE)
2891 && TREE_CODE (vr0.min) == INTEGER_CST
2892 && TREE_CODE (vr0.max) == INTEGER_CST
2893 && (!is_overflow_infinity (vr0.min)
2894 || (vr0.type == VR_RANGE
2895 && TYPE_PRECISION (outer_type) > TYPE_PRECISION (inner_type)
2896 && needs_overflow_infinity (outer_type)
2897 && supports_overflow_infinity (outer_type)))
2898 && (!is_overflow_infinity (vr0.max)
2899 || (vr0.type == VR_RANGE
2900 && TYPE_PRECISION (outer_type) > TYPE_PRECISION (inner_type)
2901 && needs_overflow_infinity (outer_type)
2902 && supports_overflow_infinity (outer_type)))
2903 && (TYPE_PRECISION (outer_type) >= TYPE_PRECISION (inner_type)
2904 || (vr0.type == VR_RANGE
2905 && integer_zerop (int_const_binop (RSHIFT_EXPR,
2906 int_const_binop (MINUS_EXPR, vr0.max, vr0.min, 0),
2907 size_int (TYPE_PRECISION (outer_type)), 0)))))
2909 tree new_min, new_max;
2910 new_min = force_fit_type_double (outer_type,
2911 tree_to_double_int (vr0.min),
2913 new_max = force_fit_type_double (outer_type,
2914 tree_to_double_int (vr0.max),
2916 if (is_overflow_infinity (vr0.min))
2917 new_min = negative_overflow_infinity (outer_type);
2918 if (is_overflow_infinity (vr0.max))
2919 new_max = positive_overflow_infinity (outer_type);
2920 set_and_canonicalize_value_range (vr, vr0.type,
2921 new_min, new_max, NULL);
2925 set_value_range_to_varying (vr);
2929 /* Conversion of a VR_VARYING value to a wider type can result
2930 in a usable range. So wait until after we've handled conversions
2931 before dropping the result to VR_VARYING if we had a source
2932 operand that is VR_VARYING. */
2933 if (vr0.type == VR_VARYING)
2935 set_value_range_to_varying (vr);
2939 /* Apply the operation to each end of the range and see what we end
2941 if (code == NEGATE_EXPR
2942 && !TYPE_UNSIGNED (type))
2944 /* NEGATE_EXPR flips the range around. We need to treat
2945 TYPE_MIN_VALUE specially. */
2946 if (is_positive_overflow_infinity (vr0.max))
2947 min = negative_overflow_infinity (type);
2948 else if (is_negative_overflow_infinity (vr0.max))
2949 min = positive_overflow_infinity (type);
2950 else if (!vrp_val_is_min (vr0.max))
2951 min = fold_unary_to_constant (code, type, vr0.max);
2952 else if (needs_overflow_infinity (type))
2954 if (supports_overflow_infinity (type)
2955 && !is_overflow_infinity (vr0.min)
2956 && !vrp_val_is_min (vr0.min))
2957 min = positive_overflow_infinity (type);
2960 set_value_range_to_varying (vr);
2965 min = TYPE_MIN_VALUE (type);
2967 if (is_positive_overflow_infinity (vr0.min))
2968 max = negative_overflow_infinity (type);
2969 else if (is_negative_overflow_infinity (vr0.min))
2970 max = positive_overflow_infinity (type);
2971 else if (!vrp_val_is_min (vr0.min))
2972 max = fold_unary_to_constant (code, type, vr0.min);
2973 else if (needs_overflow_infinity (type))
2975 if (supports_overflow_infinity (type))
2976 max = positive_overflow_infinity (type);
2979 set_value_range_to_varying (vr);
2984 max = TYPE_MIN_VALUE (type);
2986 else if (code == NEGATE_EXPR
2987 && TYPE_UNSIGNED (type))
2989 if (!range_includes_zero_p (&vr0))
2991 max = fold_unary_to_constant (code, type, vr0.min);
2992 min = fold_unary_to_constant (code, type, vr0.max);
2996 if (range_is_null (&vr0))
2997 set_value_range_to_null (vr, type);
2999 set_value_range_to_varying (vr);
3003 else if (code == ABS_EXPR
3004 && !TYPE_UNSIGNED (type))
3006 /* -TYPE_MIN_VALUE = TYPE_MIN_VALUE with flag_wrapv so we can't get a
3008 if (!TYPE_OVERFLOW_UNDEFINED (type)
3009 && ((vr0.type == VR_RANGE
3010 && vrp_val_is_min (vr0.min))
3011 || (vr0.type == VR_ANTI_RANGE
3012 && !vrp_val_is_min (vr0.min)
3013 && !range_includes_zero_p (&vr0))))
3015 set_value_range_to_varying (vr);
3019 /* ABS_EXPR may flip the range around, if the original range
3020 included negative values. */
3021 if (is_overflow_infinity (vr0.min))
3022 min = positive_overflow_infinity (type);
3023 else if (!vrp_val_is_min (vr0.min))
3024 min = fold_unary_to_constant (code, type, vr0.min);
3025 else if (!needs_overflow_infinity (type))
3026 min = TYPE_MAX_VALUE (type);
3027 else if (supports_overflow_infinity (type))
3028 min = positive_overflow_infinity (type);
3031 set_value_range_to_varying (vr);
3035 if (is_overflow_infinity (vr0.max))
3036 max = positive_overflow_infinity (type);
3037 else if (!vrp_val_is_min (vr0.max))
3038 max = fold_unary_to_constant (code, type, vr0.max);
3039 else if (!needs_overflow_infinity (type))
3040 max = TYPE_MAX_VALUE (type);
3041 else if (supports_overflow_infinity (type)
3042 /* We shouldn't generate [+INF, +INF] as set_value_range
3043 doesn't like this and ICEs. */
3044 && !is_positive_overflow_infinity (min))
3045 max = positive_overflow_infinity (type);
3048 set_value_range_to_varying (vr);
3052 cmp = compare_values (min, max);
3054 /* If a VR_ANTI_RANGEs contains zero, then we have
3055 ~[-INF, min(MIN, MAX)]. */
3056 if (vr0.type == VR_ANTI_RANGE)
3058 if (range_includes_zero_p (&vr0))
3060 /* Take the lower of the two values. */
3064 /* Create ~[-INF, min (abs(MIN), abs(MAX))]
3065 or ~[-INF + 1, min (abs(MIN), abs(MAX))] when
3066 flag_wrapv is set and the original anti-range doesn't include
3067 TYPE_MIN_VALUE, remember -TYPE_MIN_VALUE = TYPE_MIN_VALUE. */
3068 if (TYPE_OVERFLOW_WRAPS (type))
3070 tree type_min_value = TYPE_MIN_VALUE (type);
3072 min = (vr0.min != type_min_value
3073 ? int_const_binop (PLUS_EXPR, type_min_value,
3074 integer_one_node, 0)
3079 if (overflow_infinity_range_p (&vr0))
3080 min = negative_overflow_infinity (type);
3082 min = TYPE_MIN_VALUE (type);
3087 /* All else has failed, so create the range [0, INF], even for
3088 flag_wrapv since TYPE_MIN_VALUE is in the original
3090 vr0.type = VR_RANGE;
3091 min = build_int_cst (type, 0);
3092 if (needs_overflow_infinity (type))
3094 if (supports_overflow_infinity (type))
3095 max = positive_overflow_infinity (type);
3098 set_value_range_to_varying (vr);
3103 max = TYPE_MAX_VALUE (type);
3107 /* If the range contains zero then we know that the minimum value in the
3108 range will be zero. */
3109 else if (range_includes_zero_p (&vr0))
3113 min = build_int_cst (type, 0);
3117 /* If the range was reversed, swap MIN and MAX. */
3128 /* Otherwise, operate on each end of the range. */
3129 min = fold_unary_to_constant (code, type, vr0.min);
3130 max = fold_unary_to_constant (code, type, vr0.max);
3132 if (needs_overflow_infinity (type))
3134 gcc_assert (code != NEGATE_EXPR && code != ABS_EXPR);
3136 /* If both sides have overflowed, we don't know
3138 if ((is_overflow_infinity (vr0.min)
3139 || TREE_OVERFLOW (min))
3140 && (is_overflow_infinity (vr0.max)
3141 || TREE_OVERFLOW (max)))
3143 set_value_range_to_varying (vr);
3147 if (is_overflow_infinity (vr0.min))
3149 else if (TREE_OVERFLOW (min))
3151 if (supports_overflow_infinity (type))
3152 min = (tree_int_cst_sgn (min) >= 0
3153 ? positive_overflow_infinity (TREE_TYPE (min))
3154 : negative_overflow_infinity (TREE_TYPE (min)));
3157 set_value_range_to_varying (vr);
3162 if (is_overflow_infinity (vr0.max))
3164 else if (TREE_OVERFLOW (max))
3166 if (supports_overflow_infinity (type))
3167 max = (tree_int_cst_sgn (max) >= 0
3168 ? positive_overflow_infinity (TREE_TYPE (max))
3169 : negative_overflow_infinity (TREE_TYPE (max)));
3172 set_value_range_to_varying (vr);
3179 cmp = compare_values (min, max);
3180 if (cmp == -2 || cmp == 1)
3182 /* If the new range has its limits swapped around (MIN > MAX),
3183 then the operation caused one of them to wrap around, mark
3184 the new range VARYING. */
3185 set_value_range_to_varying (vr);
3188 set_value_range (vr, vr0.type, min, max, NULL);
3192 /* Extract range information from a conditional expression EXPR based on
3193 the ranges of each of its operands and the expression code. */
3196 extract_range_from_cond_expr (value_range_t *vr, tree expr)
3199 value_range_t vr0 = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
3200 value_range_t vr1 = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
3202 /* Get value ranges for each operand. For constant operands, create
3203 a new value range with the operand to simplify processing. */
3204 op0 = COND_EXPR_THEN (expr);
3205 if (TREE_CODE (op0) == SSA_NAME)
3206 vr0 = *(get_value_range (op0));
3207 else if (is_gimple_min_invariant (op0))
3208 set_value_range_to_value (&vr0, op0, NULL);
3210 set_value_range_to_varying (&vr0);
3212 op1 = COND_EXPR_ELSE (expr);
3213 if (TREE_CODE (op1) == SSA_NAME)
3214 vr1 = *(get_value_range (op1));
3215 else if (is_gimple_min_invariant (op1))
3216 set_value_range_to_value (&vr1, op1, NULL);
3218 set_value_range_to_varying (&vr1);
3220 /* The resulting value range is the union of the operand ranges */
3221 vrp_meet (&vr0, &vr1);
3222 copy_value_range (vr, &vr0);
3226 /* Extract range information from a comparison expression EXPR based
3227 on the range of its operand and the expression code. */
3230 extract_range_from_comparison (value_range_t *vr, enum tree_code code,
3231 tree type, tree op0, tree op1)
3236 val = vrp_evaluate_conditional_warnv_with_ops (code, op0, op1, false, &sop,
3239 /* A disadvantage of using a special infinity as an overflow
3240 representation is that we lose the ability to record overflow
3241 when we don't have an infinity. So we have to ignore a result
3242 which relies on overflow. */
3244 if (val && !is_overflow_infinity (val) && !sop)
3246 /* Since this expression was found on the RHS of an assignment,
3247 its type may be different from _Bool. Convert VAL to EXPR's
3249 val = fold_convert (type, val);
3250 if (is_gimple_min_invariant (val))
3251 set_value_range_to_value (vr, val, vr->equiv);
3253 set_value_range (vr, VR_RANGE, val, val, vr->equiv);
3256 /* The result of a comparison is always true or false. */
3257 set_value_range_to_truthvalue (vr, type);
3260 /* Try to derive a nonnegative or nonzero range out of STMT relying
3261 primarily on generic routines in fold in conjunction with range data.
3262 Store the result in *VR */
3265 extract_range_basic (value_range_t *vr, gimple stmt)
3268 tree type = gimple_expr_type (stmt);
3270 if (INTEGRAL_TYPE_P (type)
3271 && gimple_stmt_nonnegative_warnv_p (stmt, &sop))
3272 set_value_range_to_nonnegative (vr, type,
3273 sop || stmt_overflow_infinity (stmt));
3274 else if (vrp_stmt_computes_nonzero (stmt, &sop)
3276 set_value_range_to_nonnull (vr, type);
3278 set_value_range_to_varying (vr);
3282 /* Try to compute a useful range out of assignment STMT and store it
3286 extract_range_from_assignment (value_range_t *vr, gimple stmt)
3288 enum tree_code code = gimple_assign_rhs_code (stmt);
3290 if (code == ASSERT_EXPR)
3291 extract_range_from_assert (vr, gimple_assign_rhs1 (stmt));
3292 else if (code == SSA_NAME)
3293 extract_range_from_ssa_name (vr, gimple_assign_rhs1 (stmt));
3294 else if (TREE_CODE_CLASS (code) == tcc_binary
3295 || code == TRUTH_AND_EXPR
3296 || code == TRUTH_OR_EXPR
3297 || code == TRUTH_XOR_EXPR)
3298 extract_range_from_binary_expr (vr, gimple_assign_rhs_code (stmt),
3299 gimple_expr_type (stmt),
3300 gimple_assign_rhs1 (stmt),
3301 gimple_assign_rhs2 (stmt));
3302 else if (TREE_CODE_CLASS (code) == tcc_unary)
3303 extract_range_from_unary_expr (vr, gimple_assign_rhs_code (stmt),
3304 gimple_expr_type (stmt),
3305 gimple_assign_rhs1 (stmt));
3306 else if (code == COND_EXPR)
3307 extract_range_from_cond_expr (vr, gimple_assign_rhs1 (stmt));
3308 else if (TREE_CODE_CLASS (code) == tcc_comparison)
3309 extract_range_from_comparison (vr, gimple_assign_rhs_code (stmt),
3310 gimple_expr_type (stmt),
3311 gimple_assign_rhs1 (stmt),
3312 gimple_assign_rhs2 (stmt));
3313 else if (get_gimple_rhs_class (code) == GIMPLE_SINGLE_RHS
3314 && is_gimple_min_invariant (gimple_assign_rhs1 (stmt)))
3315 set_value_range_to_value (vr, gimple_assign_rhs1 (stmt), NULL);
3317 set_value_range_to_varying (vr);
3319 if (vr->type == VR_VARYING)
3320 extract_range_basic (vr, stmt);
3323 /* Given a range VR, a LOOP and a variable VAR, determine whether it
3324 would be profitable to adjust VR using scalar evolution information
3325 for VAR. If so, update VR with the new limits. */
3328 adjust_range_with_scev (value_range_t *vr, struct loop *loop,
3329 gimple stmt, tree var)
3331 tree init, step, chrec, tmin, tmax, min, max, type, tem;
3332 enum ev_direction dir;
3334 /* TODO. Don't adjust anti-ranges. An anti-range may provide
3335 better opportunities than a regular range, but I'm not sure. */
3336 if (vr->type == VR_ANTI_RANGE)
3339 chrec = instantiate_parameters (loop, analyze_scalar_evolution (loop, var));
3341 /* Like in PR19590, scev can return a constant function. */
3342 if (is_gimple_min_invariant (chrec))
3344 set_value_range_to_value (vr, chrec, vr->equiv);
3348 if (TREE_CODE (chrec) != POLYNOMIAL_CHREC)
3351 init = initial_condition_in_loop_num (chrec, loop->num);
3352 tem = op_with_constant_singleton_value_range (init);
3355 step = evolution_part_in_loop_num (chrec, loop->num);
3356 tem = op_with_constant_singleton_value_range (step);
3360 /* If STEP is symbolic, we can't know whether INIT will be the
3361 minimum or maximum value in the range. Also, unless INIT is
3362 a simple expression, compare_values and possibly other functions
3363 in tree-vrp won't be able to handle it. */
3364 if (step == NULL_TREE
3365 || !is_gimple_min_invariant (step)
3366 || !valid_value_p (init))
3369 dir = scev_direction (chrec);
3370 if (/* Do not adjust ranges if we do not know whether the iv increases
3371 or decreases, ... */
3372 dir == EV_DIR_UNKNOWN
3373 /* ... or if it may wrap. */
3374 || scev_probably_wraps_p (init, step, stmt, get_chrec_loop (chrec),
3378 /* We use TYPE_MIN_VALUE and TYPE_MAX_VALUE here instead of
3379 negative_overflow_infinity and positive_overflow_infinity,
3380 because we have concluded that the loop probably does not
3383 type = TREE_TYPE (var);
3384 if (POINTER_TYPE_P (type) || !TYPE_MIN_VALUE (type))
3385 tmin = lower_bound_in_type (type, type);
3387 tmin = TYPE_MIN_VALUE (type);
3388 if (POINTER_TYPE_P (type) || !TYPE_MAX_VALUE (type))
3389 tmax = upper_bound_in_type (type, type);
3391 tmax = TYPE_MAX_VALUE (type);
3393 /* Try to use estimated number of iterations for the loop to constrain the
3394 final value in the evolution.
3395 We are interested in the number of executions of the latch, while
3396 nb_iterations_upper_bound includes the last execution of the exit test. */
3397 if (TREE_CODE (step) == INTEGER_CST
3398 && loop->any_upper_bound
3399 && !double_int_zero_p (loop->nb_iterations_upper_bound)
3400 && is_gimple_val (init)
3401 && (TREE_CODE (init) != SSA_NAME
3402 || get_value_range (init)->type == VR_RANGE))
3404 value_range_t maxvr = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
3406 dtmp = double_int_mul (tree_to_double_int (step),
3407 double_int_sub (loop->nb_iterations_upper_bound,
3409 tem = double_int_to_tree (TREE_TYPE (init), dtmp);
3410 /* If the multiplication overflowed we can't do a meaningful
3412 if (double_int_equal_p (dtmp, tree_to_double_int (tem)))
3414 extract_range_from_binary_expr (&maxvr, PLUS_EXPR,
3415 TREE_TYPE (init), init, tem);
3416 /* Likewise if the addition did. */
3417 if (maxvr.type == VR_RANGE)
3425 if (vr->type == VR_VARYING || vr->type == VR_UNDEFINED)
3430 /* For VARYING or UNDEFINED ranges, just about anything we get
3431 from scalar evolutions should be better. */
3433 if (dir == EV_DIR_DECREASES)
3438 /* If we would create an invalid range, then just assume we
3439 know absolutely nothing. This may be over-conservative,
3440 but it's clearly safe, and should happen only in unreachable
3441 parts of code, or for invalid programs. */
3442 if (compare_values (min, max) == 1)
3445 set_value_range (vr, VR_RANGE, min, max, vr->equiv);
3447 else if (vr->type == VR_RANGE)
3452 if (dir == EV_DIR_DECREASES)
3454 /* INIT is the maximum value. If INIT is lower than VR->MAX
3455 but no smaller than VR->MIN, set VR->MAX to INIT. */
3456 if (compare_values (init, max) == -1)
3459 /* According to the loop information, the variable does not
3460 overflow. If we think it does, probably because of an
3461 overflow due to arithmetic on a different INF value,
3463 if (is_negative_overflow_infinity (min)
3464 || compare_values (min, tmin) == -1)
3470 /* If INIT is bigger than VR->MIN, set VR->MIN to INIT. */
3471 if (compare_values (init, min) == 1)
3474 if (is_positive_overflow_infinity (max)
3475 || compare_values (tmax, max) == -1)
3479 /* If we just created an invalid range with the minimum
3480 greater than the maximum, we fail conservatively.
3481 This should happen only in unreachable
3482 parts of code, or for invalid programs. */
3483 if (compare_values (min, max) == 1)
3486 set_value_range (vr, VR_RANGE, min, max, vr->equiv);
3490 /* Return true if VAR may overflow at STMT. This checks any available
3491 loop information to see if we can determine that VAR does not
3495 vrp_var_may_overflow (tree var, gimple stmt)
3498 tree chrec, init, step;
3500 if (current_loops == NULL)
3503 l = loop_containing_stmt (stmt);
3508 chrec = instantiate_parameters (l, analyze_scalar_evolution (l, var));
3509 if (TREE_CODE (chrec) != POLYNOMIAL_CHREC)
3512 init = initial_condition_in_loop_num (chrec, l->num);
3513 step = evolution_part_in_loop_num (chrec, l->num);
3515 if (step == NULL_TREE
3516 || !is_gimple_min_invariant (step)
3517 || !valid_value_p (init))
3520 /* If we get here, we know something useful about VAR based on the
3521 loop information. If it wraps, it may overflow. */
3523 if (scev_probably_wraps_p (init, step, stmt, get_chrec_loop (chrec),
3527 if (dump_file && (dump_flags & TDF_DETAILS) != 0)
3529 print_generic_expr (dump_file, var, 0);
3530 fprintf (dump_file, ": loop information indicates does not overflow\n");
3537 /* Given two numeric value ranges VR0, VR1 and a comparison code COMP:
3539 - Return BOOLEAN_TRUE_NODE if VR0 COMP VR1 always returns true for
3540 all the values in the ranges.
3542 - Return BOOLEAN_FALSE_NODE if the comparison always returns false.
3544 - Return NULL_TREE if it is not always possible to determine the
3545 value of the comparison.
3547 Also set *STRICT_OVERFLOW_P to indicate whether a range with an
3548 overflow infinity was used in the test. */
3552 compare_ranges (enum tree_code comp, value_range_t *vr0, value_range_t *vr1,
3553 bool *strict_overflow_p)
3555 /* VARYING or UNDEFINED ranges cannot be compared. */
3556 if (vr0->type == VR_VARYING
3557 || vr0->type == VR_UNDEFINED
3558 || vr1->type == VR_VARYING
3559 || vr1->type == VR_UNDEFINED)
3562 /* Anti-ranges need to be handled separately. */
3563 if (vr0->type == VR_ANTI_RANGE || vr1->type == VR_ANTI_RANGE)
3565 /* If both are anti-ranges, then we cannot compute any
3567 if (vr0->type == VR_ANTI_RANGE && vr1->type == VR_ANTI_RANGE)
3570 /* These comparisons are never statically computable. */
3577 /* Equality can be computed only between a range and an
3578 anti-range. ~[VAL1, VAL2] == [VAL1, VAL2] is always false. */
3579 if (vr0->type == VR_RANGE)
3581 /* To simplify processing, make VR0 the anti-range. */
3582 value_range_t *tmp = vr0;
3587 gcc_assert (comp == NE_EXPR || comp == EQ_EXPR);
3589 if (compare_values_warnv (vr0->min, vr1->min, strict_overflow_p) == 0
3590 && compare_values_warnv (vr0->max, vr1->max, strict_overflow_p) == 0)
3591 return (comp == NE_EXPR) ? boolean_true_node : boolean_false_node;
3596 if (!usable_range_p (vr0, strict_overflow_p)
3597 || !usable_range_p (vr1, strict_overflow_p))
3600 /* Simplify processing. If COMP is GT_EXPR or GE_EXPR, switch the
3601 operands around and change the comparison code. */
3602 if (comp == GT_EXPR || comp == GE_EXPR)
3605 comp = (comp == GT_EXPR) ? LT_EXPR : LE_EXPR;
3611 if (comp == EQ_EXPR)
3613 /* Equality may only be computed if both ranges represent
3614 exactly one value. */
3615 if (compare_values_warnv (vr0->min, vr0->max, strict_overflow_p) == 0
3616 && compare_values_warnv (vr1->min, vr1->max, strict_overflow_p) == 0)
3618 int cmp_min = compare_values_warnv (vr0->min, vr1->min,
3620 int cmp_max = compare_values_warnv (vr0->max, vr1->max,
3622 if (cmp_min == 0 && cmp_max == 0)
3623 return boolean_true_node;
3624 else if (cmp_min != -2 && cmp_max != -2)
3625 return boolean_false_node;
3627 /* If [V0_MIN, V1_MAX] < [V1_MIN, V1_MAX] then V0 != V1. */
3628 else if (compare_values_warnv (vr0->min, vr1->max,
3629 strict_overflow_p) == 1
3630 || compare_values_warnv (vr1->min, vr0->max,
3631 strict_overflow_p) == 1)
3632 return boolean_false_node;
3636 else if (comp == NE_EXPR)
3640 /* If VR0 is completely to the left or completely to the right
3641 of VR1, they are always different. Notice that we need to
3642 make sure that both comparisons yield similar results to
3643 avoid comparing values that cannot be compared at
3645 cmp1 = compare_values_warnv (vr0->max, vr1->min, strict_overflow_p);
3646 cmp2 = compare_values_warnv (vr0->min, vr1->max, strict_overflow_p);
3647 if ((cmp1 == -1 && cmp2 == -1) || (cmp1 == 1 && cmp2 == 1))
3648 return boolean_true_node;
3650 /* If VR0 and VR1 represent a single value and are identical,
3652 else if (compare_values_warnv (vr0->min, vr0->max,
3653 strict_overflow_p) == 0
3654 && compare_values_warnv (vr1->min, vr1->max,
3655 strict_overflow_p) == 0
3656 && compare_values_warnv (vr0->min, vr1->min,
3657 strict_overflow_p) == 0
3658 && compare_values_warnv (vr0->max, vr1->max,
3659 strict_overflow_p) == 0)
3660 return boolean_false_node;
3662 /* Otherwise, they may or may not be different. */
3666 else if (comp == LT_EXPR || comp == LE_EXPR)
3670 /* If VR0 is to the left of VR1, return true. */
3671 tst = compare_values_warnv (vr0->max, vr1->min, strict_overflow_p);
3672 if ((comp == LT_EXPR && tst == -1)
3673 || (comp == LE_EXPR && (tst == -1 || tst == 0)))
3675 if (overflow_infinity_range_p (vr0)
3676 || overflow_infinity_range_p (vr1))
3677 *strict_overflow_p = true;
3678 return boolean_true_node;
3681 /* If VR0 is to the right of VR1, return false. */
3682 tst = compare_values_warnv (vr0->min, vr1->max, strict_overflow_p);
3683 if ((comp == LT_EXPR && (tst == 0 || tst == 1))
3684 || (comp == LE_EXPR && tst == 1))
3686 if (overflow_infinity_range_p (vr0)
3687 || overflow_infinity_range_p (vr1))
3688 *strict_overflow_p = true;
3689 return boolean_false_node;
3692 /* Otherwise, we don't know. */
3700 /* Given a value range VR, a value VAL and a comparison code COMP, return
3701 BOOLEAN_TRUE_NODE if VR COMP VAL always returns true for all the
3702 values in VR. Return BOOLEAN_FALSE_NODE if the comparison
3703 always returns false. Return NULL_TREE if it is not always
3704 possible to determine the value of the comparison. Also set
3705 *STRICT_OVERFLOW_P to indicate whether a range with an overflow
3706 infinity was used in the test. */
3709 compare_range_with_value (enum tree_code comp, value_range_t *vr, tree val,
3710 bool *strict_overflow_p)
3712 if (vr->type == VR_VARYING || vr->type == VR_UNDEFINED)
3715 /* Anti-ranges need to be handled separately. */
3716 if (vr->type == VR_ANTI_RANGE)
3718 /* For anti-ranges, the only predicates that we can compute at
3719 compile time are equality and inequality. */
3726 /* ~[VAL_1, VAL_2] OP VAL is known if VAL_1 <= VAL <= VAL_2. */
3727 if (value_inside_range (val, vr) == 1)
3728 return (comp == NE_EXPR) ? boolean_true_node : boolean_false_node;
3733 if (!usable_range_p (vr, strict_overflow_p))
3736 if (comp == EQ_EXPR)
3738 /* EQ_EXPR may only be computed if VR represents exactly
3740 if (compare_values_warnv (vr->min, vr->max, strict_overflow_p) == 0)
3742 int cmp = compare_values_warnv (vr->min, val, strict_overflow_p);
3744 return boolean_true_node;
3745 else if (cmp == -1 || cmp == 1 || cmp == 2)
3746 return boolean_false_node;
3748 else if (compare_values_warnv (val, vr->min, strict_overflow_p) == -1
3749 || compare_values_warnv (vr->max, val, strict_overflow_p) == -1)
3750 return boolean_false_node;
3754 else if (comp == NE_EXPR)
3756 /* If VAL is not inside VR, then they are always different. */
3757 if (compare_values_warnv (vr->max, val, strict_overflow_p) == -1
3758 || compare_values_warnv (vr->min, val, strict_overflow_p) == 1)
3759 return boolean_true_node;
3761 /* If VR represents exactly one value equal to VAL, then return
3763 if (compare_values_warnv (vr->min, vr->max, strict_overflow_p) == 0
3764 && compare_values_warnv (vr->min, val, strict_overflow_p) == 0)
3765 return boolean_false_node;
3767 /* Otherwise, they may or may not be different. */
3770 else if (comp == LT_EXPR || comp == LE_EXPR)
3774 /* If VR is to the left of VAL, return true. */
3775 tst = compare_values_warnv (vr->max, val, strict_overflow_p);
3776 if ((comp == LT_EXPR && tst == -1)
3777 || (comp == LE_EXPR && (tst == -1 || tst == 0)))
3779 if (overflow_infinity_range_p (vr))
3780 *strict_overflow_p = true;
3781 return boolean_true_node;
3784 /* If VR is to the right of VAL, return false. */
3785 tst = compare_values_warnv (vr->min, val, strict_overflow_p);
3786 if ((comp == LT_EXPR && (tst == 0 || tst == 1))
3787 || (comp == LE_EXPR && tst == 1))
3789 if (overflow_infinity_range_p (vr))
3790 *strict_overflow_p = true;
3791 return boolean_false_node;
3794 /* Otherwise, we don't know. */
3797 else if (comp == GT_EXPR || comp == GE_EXPR)
3801 /* If VR is to the right of VAL, return true. */
3802 tst = compare_values_warnv (vr->min, val, strict_overflow_p);
3803 if ((comp == GT_EXPR && tst == 1)
3804 || (comp == GE_EXPR && (tst == 0 || tst == 1)))
3806 if (overflow_infinity_range_p (vr))
3807 *strict_overflow_p = true;
3808 return boolean_true_node;
3811 /* If VR is to the left of VAL, return false. */
3812 tst = compare_values_warnv (vr->max, val, strict_overflow_p);
3813 if ((comp == GT_EXPR && (tst == -1 || tst == 0))
3814 || (comp == GE_EXPR && tst == -1))
3816 if (overflow_infinity_range_p (vr))
3817 *strict_overflow_p = true;
3818 return boolean_false_node;
3821 /* Otherwise, we don't know. */
3829 /* Debugging dumps. */
3831 void dump_value_range (FILE *, value_range_t *);
3832 void debug_value_range (value_range_t *);
3833 void dump_all_value_ranges (FILE *);
3834 void debug_all_value_ranges (void);
3835 void dump_vr_equiv (FILE *, bitmap);
3836 void debug_vr_equiv (bitmap);
3839 /* Dump value range VR to FILE. */
3842 dump_value_range (FILE *file, value_range_t *vr)
3845 fprintf (file, "[]");
3846 else if (vr->type == VR_UNDEFINED)
3847 fprintf (file, "UNDEFINED");
3848 else if (vr->type == VR_RANGE || vr->type == VR_ANTI_RANGE)
3850 tree type = TREE_TYPE (vr->min);
3852 fprintf (file, "%s[", (vr->type == VR_ANTI_RANGE) ? "~" : "");
3854 if (is_negative_overflow_infinity (vr->min))
3855 fprintf (file, "-INF(OVF)");
3856 else if (INTEGRAL_TYPE_P (type)
3857 && !TYPE_UNSIGNED (type)
3858 && vrp_val_is_min (vr->min))
3859 fprintf (file, "-INF");
3861 print_generic_expr (file, vr->min, 0);
3863 fprintf (file, ", ");
3865 if (is_positive_overflow_infinity (vr->max))
3866 fprintf (file, "+INF(OVF)");
3867 else if (INTEGRAL_TYPE_P (type)
3868 && vrp_val_is_max (vr->max))
3869 fprintf (file, "+INF");
3871 print_generic_expr (file, vr->max, 0);
3873 fprintf (file, "]");
3880 fprintf (file, " EQUIVALENCES: { ");
3882 EXECUTE_IF_SET_IN_BITMAP (vr->equiv, 0, i, bi)
3884 print_generic_expr (file, ssa_name (i), 0);
3885 fprintf (file, " ");
3889 fprintf (file, "} (%u elements)", c);
3892 else if (vr->type == VR_VARYING)
3893 fprintf (file, "VARYING");
3895 fprintf (file, "INVALID RANGE");
3899 /* Dump value range VR to stderr. */
3902 debug_value_range (value_range_t *vr)
3904 dump_value_range (stderr, vr);
3905 fprintf (stderr, "\n");
3909 /* Dump value ranges of all SSA_NAMEs to FILE. */
3912 dump_all_value_ranges (FILE *file)
3916 for (i = 0; i < num_ssa_names; i++)
3920 print_generic_expr (file, ssa_name (i), 0);
3921 fprintf (file, ": ");
3922 dump_value_range (file, vr_value[i]);
3923 fprintf (file, "\n");
3927 fprintf (file, "\n");
3931 /* Dump all value ranges to stderr. */
3934 debug_all_value_ranges (void)
3936 dump_all_value_ranges (stderr);
3940 /* Given a COND_EXPR COND of the form 'V OP W', and an SSA name V,
3941 create a new SSA name N and return the assertion assignment
3942 'V = ASSERT_EXPR <V, V OP W>'. */
3945 build_assert_expr_for (tree cond, tree v)
3950 gcc_assert (TREE_CODE (v) == SSA_NAME);
3951 n = duplicate_ssa_name (v, NULL);
3953 if (COMPARISON_CLASS_P (cond))
3955 tree a = build2 (ASSERT_EXPR, TREE_TYPE (v), v, cond);
3956 assertion = gimple_build_assign (n, a);
3958 else if (TREE_CODE (cond) == TRUTH_NOT_EXPR)
3960 /* Given !V, build the assignment N = false. */
3961 tree op0 = TREE_OPERAND (cond, 0);
3962 gcc_assert (op0 == v);
3963 assertion = gimple_build_assign (n, boolean_false_node);
3965 else if (TREE_CODE (cond) == SSA_NAME)
3967 /* Given V, build the assignment N = true. */
3968 gcc_assert (v == cond);
3969 assertion = gimple_build_assign (n, boolean_true_node);
3974 SSA_NAME_DEF_STMT (n) = assertion;
3976 /* The new ASSERT_EXPR, creates a new SSA name that replaces the
3977 operand of the ASSERT_EXPR. Register the new name and the old one
3978 in the replacement table so that we can fix the SSA web after
3979 adding all the ASSERT_EXPRs. */
3980 register_new_name_mapping (n, v);
3986 /* Return false if EXPR is a predicate expression involving floating
3990 fp_predicate (gimple stmt)
3992 GIMPLE_CHECK (stmt, GIMPLE_COND);
3994 return FLOAT_TYPE_P (TREE_TYPE (gimple_cond_lhs (stmt)));
3998 /* If the range of values taken by OP can be inferred after STMT executes,
3999 return the comparison code (COMP_CODE_P) and value (VAL_P) that
4000 describes the inferred range. Return true if a range could be
4004 infer_value_range (gimple stmt, tree op, enum tree_code *comp_code_p, tree *val_p)
4007 *comp_code_p = ERROR_MARK;
4009 /* Do not attempt to infer anything in names that flow through
4011 if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (op))
4014 /* Similarly, don't infer anything from statements that may throw
4016 if (stmt_could_throw_p (stmt))
4019 /* If STMT is the last statement of a basic block with no
4020 successors, there is no point inferring anything about any of its
4021 operands. We would not be able to find a proper insertion point
4022 for the assertion, anyway. */
4023 if (stmt_ends_bb_p (stmt) && EDGE_COUNT (gimple_bb (stmt)->succs) == 0)
4026 /* We can only assume that a pointer dereference will yield
4027 non-NULL if -fdelete-null-pointer-checks is enabled. */
4028 if (flag_delete_null_pointer_checks
4029 && POINTER_TYPE_P (TREE_TYPE (op))
4030 && gimple_code (stmt) != GIMPLE_ASM)
4032 unsigned num_uses, num_loads, num_stores;
4034 count_uses_and_derefs (op, stmt, &num_uses, &num_loads, &num_stores);
4035 if (num_loads + num_stores > 0)
4037 *val_p = build_int_cst (TREE_TYPE (op), 0);
4038 *comp_code_p = NE_EXPR;
4047 void dump_asserts_for (FILE *, tree);
4048 void debug_asserts_for (tree);
4049 void dump_all_asserts (FILE *);
4050 void debug_all_asserts (void);
4052 /* Dump all the registered assertions for NAME to FILE. */
4055 dump_asserts_for (FILE *file, tree name)
4059 fprintf (file, "Assertions to be inserted for ");
4060 print_generic_expr (file, name, 0);
4061 fprintf (file, "\n");
4063 loc = asserts_for[SSA_NAME_VERSION (name)];
4066 fprintf (file, "\t");
4067 print_gimple_stmt (file, gsi_stmt (loc->si), 0, 0);
4068 fprintf (file, "\n\tBB #%d", loc->bb->index);
4071 fprintf (file, "\n\tEDGE %d->%d", loc->e->src->index,
4072 loc->e->dest->index);
4073 dump_edge_info (file, loc->e, 0);
4075 fprintf (file, "\n\tPREDICATE: ");
4076 print_generic_expr (file, name, 0);
4077 fprintf (file, " %s ", tree_code_name[(int)loc->comp_code]);
4078 print_generic_expr (file, loc->val, 0);
4079 fprintf (file, "\n\n");
4083 fprintf (file, "\n");
4087 /* Dump all the registered assertions for NAME to stderr. */
4090 debug_asserts_for (tree name)
4092 dump_asserts_for (stderr, name);
4096 /* Dump all the registered assertions for all the names to FILE. */
4099 dump_all_asserts (FILE *file)
4104 fprintf (file, "\nASSERT_EXPRs to be inserted\n\n");
4105 EXECUTE_IF_SET_IN_BITMAP (need_assert_for, 0, i, bi)
4106 dump_asserts_for (file, ssa_name (i));
4107 fprintf (file, "\n");
4111 /* Dump all the registered assertions for all the names to stderr. */
4114 debug_all_asserts (void)
4116 dump_all_asserts (stderr);
4120 /* If NAME doesn't have an ASSERT_EXPR registered for asserting
4121 'EXPR COMP_CODE VAL' at a location that dominates block BB or
4122 E->DEST, then register this location as a possible insertion point
4123 for ASSERT_EXPR <NAME, EXPR COMP_CODE VAL>.
4125 BB, E and SI provide the exact insertion point for the new
4126 ASSERT_EXPR. If BB is NULL, then the ASSERT_EXPR is to be inserted
4127 on edge E. Otherwise, if E is NULL, the ASSERT_EXPR is inserted on
4128 BB. If SI points to a COND_EXPR or a SWITCH_EXPR statement, then E
4129 must not be NULL. */
4132 register_new_assert_for (tree name, tree expr,
4133 enum tree_code comp_code,
4137 gimple_stmt_iterator si)
4139 assert_locus_t n, loc, last_loc;
4140 basic_block dest_bb;
4142 gcc_checking_assert (bb == NULL || e == NULL);
4145 gcc_checking_assert (gimple_code (gsi_stmt (si)) != GIMPLE_COND
4146 && gimple_code (gsi_stmt (si)) != GIMPLE_SWITCH);
4148 /* Never build an assert comparing against an integer constant with
4149 TREE_OVERFLOW set. This confuses our undefined overflow warning
4151 if (TREE_CODE (val) == INTEGER_CST
4152 && TREE_OVERFLOW (val))
4153 val = build_int_cst_wide (TREE_TYPE (val),
4154 TREE_INT_CST_LOW (val), TREE_INT_CST_HIGH (val));
4156 /* The new assertion A will be inserted at BB or E. We need to
4157 determine if the new location is dominated by a previously
4158 registered location for A. If we are doing an edge insertion,
4159 assume that A will be inserted at E->DEST. Note that this is not
4162 If E is a critical edge, it will be split. But even if E is
4163 split, the new block will dominate the same set of blocks that
4166 The reverse, however, is not true, blocks dominated by E->DEST
4167 will not be dominated by the new block created to split E. So,
4168 if the insertion location is on a critical edge, we will not use
4169 the new location to move another assertion previously registered
4170 at a block dominated by E->DEST. */
4171 dest_bb = (bb) ? bb : e->dest;
4173 /* If NAME already has an ASSERT_EXPR registered for COMP_CODE and
4174 VAL at a block dominating DEST_BB, then we don't need to insert a new
4175 one. Similarly, if the same assertion already exists at a block
4176 dominated by DEST_BB and the new location is not on a critical
4177 edge, then update the existing location for the assertion (i.e.,
4178 move the assertion up in the dominance tree).
4180 Note, this is implemented as a simple linked list because there
4181 should not be more than a handful of assertions registered per
4182 name. If this becomes a performance problem, a table hashed by
4183 COMP_CODE and VAL could be implemented. */
4184 loc = asserts_for[SSA_NAME_VERSION (name)];
4188 if (loc->comp_code == comp_code
4190 || operand_equal_p (loc->val, val, 0))
4191 && (loc->expr == expr
4192 || operand_equal_p (loc->expr, expr, 0)))
4194 /* If the assertion NAME COMP_CODE VAL has already been
4195 registered at a basic block that dominates DEST_BB, then
4196 we don't need to insert the same assertion again. Note
4197 that we don't check strict dominance here to avoid
4198 replicating the same assertion inside the same basic
4199 block more than once (e.g., when a pointer is
4200 dereferenced several times inside a block).
4202 An exception to this rule are edge insertions. If the
4203 new assertion is to be inserted on edge E, then it will
4204 dominate all the other insertions that we may want to
4205 insert in DEST_BB. So, if we are doing an edge
4206 insertion, don't do this dominance check. */
4208 && dominated_by_p (CDI_DOMINATORS, dest_bb, loc->bb))
4211 /* Otherwise, if E is not a critical edge and DEST_BB
4212 dominates the existing location for the assertion, move
4213 the assertion up in the dominance tree by updating its
4214 location information. */
4215 if ((e == NULL || !EDGE_CRITICAL_P (e))
4216 && dominated_by_p (CDI_DOMINATORS, loc->bb, dest_bb))
4225 /* Update the last node of the list and move to the next one. */
4230 /* If we didn't find an assertion already registered for
4231 NAME COMP_CODE VAL, add a new one at the end of the list of
4232 assertions associated with NAME. */
4233 n = XNEW (struct assert_locus_d);
4237 n->comp_code = comp_code;
4245 asserts_for[SSA_NAME_VERSION (name)] = n;
4247 bitmap_set_bit (need_assert_for, SSA_NAME_VERSION (name));
4250 /* (COND_OP0 COND_CODE COND_OP1) is a predicate which uses NAME.
4251 Extract a suitable test code and value and store them into *CODE_P and
4252 *VAL_P so the predicate is normalized to NAME *CODE_P *VAL_P.
4254 If no extraction was possible, return FALSE, otherwise return TRUE.
4256 If INVERT is true, then we invert the result stored into *CODE_P. */
4259 extract_code_and_val_from_cond_with_ops (tree name, enum tree_code cond_code,
4260 tree cond_op0, tree cond_op1,
4261 bool invert, enum tree_code *code_p,
4264 enum tree_code comp_code;
4267 /* Otherwise, we have a comparison of the form NAME COMP VAL
4268 or VAL COMP NAME. */
4269 if (name == cond_op1)
4271 /* If the predicate is of the form VAL COMP NAME, flip
4272 COMP around because we need to register NAME as the
4273 first operand in the predicate. */
4274 comp_code = swap_tree_comparison (cond_code);
4279 /* The comparison is of the form NAME COMP VAL, so the
4280 comparison code remains unchanged. */
4281 comp_code = cond_code;
4285 /* Invert the comparison code as necessary. */
4287 comp_code = invert_tree_comparison (comp_code, 0);
4289 /* VRP does not handle float types. */
4290 if (SCALAR_FLOAT_TYPE_P (TREE_TYPE (val)))
4293 /* Do not register always-false predicates.
4294 FIXME: this works around a limitation in fold() when dealing with
4295 enumerations. Given 'enum { N1, N2 } x;', fold will not
4296 fold 'if (x > N2)' to 'if (0)'. */
4297 if ((comp_code == GT_EXPR || comp_code == LT_EXPR)
4298 && INTEGRAL_TYPE_P (TREE_TYPE (val)))
4300 tree min = TYPE_MIN_VALUE (TREE_TYPE (val));
4301 tree max = TYPE_MAX_VALUE (TREE_TYPE (val));
4303 if (comp_code == GT_EXPR
4305 || compare_values (val, max) == 0))
4308 if (comp_code == LT_EXPR
4310 || compare_values (val, min) == 0))
4313 *code_p = comp_code;
4318 /* Try to register an edge assertion for SSA name NAME on edge E for
4319 the condition COND contributing to the conditional jump pointed to by BSI.
4320 Invert the condition COND if INVERT is true.
4321 Return true if an assertion for NAME could be registered. */
4324 register_edge_assert_for_2 (tree name, edge e, gimple_stmt_iterator bsi,
4325 enum tree_code cond_code,
4326 tree cond_op0, tree cond_op1, bool invert)
4329 enum tree_code comp_code;
4330 bool retval = false;
4332 if (!extract_code_and_val_from_cond_with_ops (name, cond_code,
4335 invert, &comp_code, &val))
4338 /* Only register an ASSERT_EXPR if NAME was found in the sub-graph
4339 reachable from E. */
4340 if (live_on_edge (e, name)
4341 && !has_single_use (name))
4343 register_new_assert_for (name, name, comp_code, val, NULL, e, bsi);
4347 /* In the case of NAME <= CST and NAME being defined as
4348 NAME = (unsigned) NAME2 + CST2 we can assert NAME2 >= -CST2
4349 and NAME2 <= CST - CST2. We can do the same for NAME > CST.
4350 This catches range and anti-range tests. */
4351 if ((comp_code == LE_EXPR
4352 || comp_code == GT_EXPR)
4353 && TREE_CODE (val) == INTEGER_CST
4354 && TYPE_UNSIGNED (TREE_TYPE (val)))
4356 gimple def_stmt = SSA_NAME_DEF_STMT (name);
4357 tree cst2 = NULL_TREE, name2 = NULL_TREE, name3 = NULL_TREE;
4359 /* Extract CST2 from the (optional) addition. */
4360 if (is_gimple_assign (def_stmt)
4361 && gimple_assign_rhs_code (def_stmt) == PLUS_EXPR)
4363 name2 = gimple_assign_rhs1 (def_stmt);
4364 cst2 = gimple_assign_rhs2 (def_stmt);
4365 if (TREE_CODE (name2) == SSA_NAME
4366 && TREE_CODE (cst2) == INTEGER_CST)
4367 def_stmt = SSA_NAME_DEF_STMT (name2);
4370 /* Extract NAME2 from the (optional) sign-changing cast. */
4371 if (gimple_assign_cast_p (def_stmt))
4373 if (CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (def_stmt))
4374 && ! TYPE_UNSIGNED (TREE_TYPE (gimple_assign_rhs1 (def_stmt)))
4375 && (TYPE_PRECISION (gimple_expr_type (def_stmt))
4376 == TYPE_PRECISION (TREE_TYPE (gimple_assign_rhs1 (def_stmt)))))
4377 name3 = gimple_assign_rhs1 (def_stmt);
4380 /* If name3 is used later, create an ASSERT_EXPR for it. */
4381 if (name3 != NULL_TREE
4382 && TREE_CODE (name3) == SSA_NAME
4383 && (cst2 == NULL_TREE
4384 || TREE_CODE (cst2) == INTEGER_CST)
4385 && INTEGRAL_TYPE_P (TREE_TYPE (name3))
4386 && live_on_edge (e, name3)
4387 && !has_single_use (name3))
4391 /* Build an expression for the range test. */
4392 tmp = build1 (NOP_EXPR, TREE_TYPE (name), name3);
4393 if (cst2 != NULL_TREE)
4394 tmp = build2 (PLUS_EXPR, TREE_TYPE (name), tmp, cst2);
4398 fprintf (dump_file, "Adding assert for ");
4399 print_generic_expr (dump_file, name3, 0);
4400 fprintf (dump_file, " from ");
4401 print_generic_expr (dump_file, tmp, 0);
4402 fprintf (dump_file, "\n");
4405 register_new_assert_for (name3, tmp, comp_code, val, NULL, e, bsi);
4410 /* If name2 is used later, create an ASSERT_EXPR for it. */
4411 if (name2 != NULL_TREE
4412 && TREE_CODE (name2) == SSA_NAME
4413 && TREE_CODE (cst2) == INTEGER_CST
4414 && INTEGRAL_TYPE_P (TREE_TYPE (name2))
4415 && live_on_edge (e, name2)
4416 && !has_single_use (name2))
4420 /* Build an expression for the range test. */
4422 if (TREE_TYPE (name) != TREE_TYPE (name2))
4423 tmp = build1 (NOP_EXPR, TREE_TYPE (name), tmp);
4424 if (cst2 != NULL_TREE)
4425 tmp = build2 (PLUS_EXPR, TREE_TYPE (name), tmp, cst2);
4429 fprintf (dump_file, "Adding assert for ");
4430 print_generic_expr (dump_file, name2, 0);
4431 fprintf (dump_file, " from ");
4432 print_generic_expr (dump_file, tmp, 0);
4433 fprintf (dump_file, "\n");
4436 register_new_assert_for (name2, tmp, comp_code, val, NULL, e, bsi);
4445 /* OP is an operand of a truth value expression which is known to have
4446 a particular value. Register any asserts for OP and for any
4447 operands in OP's defining statement.
4449 If CODE is EQ_EXPR, then we want to register OP is zero (false),
4450 if CODE is NE_EXPR, then we want to register OP is nonzero (true). */
4453 register_edge_assert_for_1 (tree op, enum tree_code code,
4454 edge e, gimple_stmt_iterator bsi)
4456 bool retval = false;
4459 enum tree_code rhs_code;
4461 /* We only care about SSA_NAMEs. */
4462 if (TREE_CODE (op) != SSA_NAME)
4465 /* We know that OP will have a zero or nonzero value. If OP is used
4466 more than once go ahead and register an assert for OP.
4468 The FOUND_IN_SUBGRAPH support is not helpful in this situation as
4469 it will always be set for OP (because OP is used in a COND_EXPR in
4471 if (!has_single_use (op))
4473 val = build_int_cst (TREE_TYPE (op), 0);
4474 register_new_assert_for (op, op, code, val, NULL, e, bsi);
4478 /* Now look at how OP is set. If it's set from a comparison,
4479 a truth operation or some bit operations, then we may be able
4480 to register information about the operands of that assignment. */
4481 op_def = SSA_NAME_DEF_STMT (op);
4482 if (gimple_code (op_def) != GIMPLE_ASSIGN)
4485 rhs_code = gimple_assign_rhs_code (op_def);
4487 if (TREE_CODE_CLASS (rhs_code) == tcc_comparison)
4489 bool invert = (code == EQ_EXPR ? true : false);
4490 tree op0 = gimple_assign_rhs1 (op_def);
4491 tree op1 = gimple_assign_rhs2 (op_def);
4493 if (TREE_CODE (op0) == SSA_NAME)
4494 retval |= register_edge_assert_for_2 (op0, e, bsi, rhs_code, op0, op1,
4496 if (TREE_CODE (op1) == SSA_NAME)
4497 retval |= register_edge_assert_for_2 (op1, e, bsi, rhs_code, op0, op1,
4500 else if ((code == NE_EXPR
4501 && (gimple_assign_rhs_code (op_def) == TRUTH_AND_EXPR
4502 || gimple_assign_rhs_code (op_def) == BIT_AND_EXPR))
4504 && (gimple_assign_rhs_code (op_def) == TRUTH_OR_EXPR
4505 || gimple_assign_rhs_code (op_def) == BIT_IOR_EXPR)))
4507 /* Recurse on each operand. */
4508 retval |= register_edge_assert_for_1 (gimple_assign_rhs1 (op_def),
4510 retval |= register_edge_assert_for_1 (gimple_assign_rhs2 (op_def),
4513 else if (gimple_assign_rhs_code (op_def) == TRUTH_NOT_EXPR)
4515 /* Recurse, flipping CODE. */
4516 code = invert_tree_comparison (code, false);
4517 retval |= register_edge_assert_for_1 (gimple_assign_rhs1 (op_def),
4520 else if (gimple_assign_rhs_code (op_def) == SSA_NAME)
4522 /* Recurse through the copy. */
4523 retval |= register_edge_assert_for_1 (gimple_assign_rhs1 (op_def),
4526 else if (CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (op_def)))
4528 /* Recurse through the type conversion. */
4529 retval |= register_edge_assert_for_1 (gimple_assign_rhs1 (op_def),
4536 /* Try to register an edge assertion for SSA name NAME on edge E for
4537 the condition COND contributing to the conditional jump pointed to by SI.
4538 Return true if an assertion for NAME could be registered. */
4541 register_edge_assert_for (tree name, edge e, gimple_stmt_iterator si,
4542 enum tree_code cond_code, tree cond_op0,
4546 enum tree_code comp_code;
4547 bool retval = false;
4548 bool is_else_edge = (e->flags & EDGE_FALSE_VALUE) != 0;
4550 /* Do not attempt to infer anything in names that flow through
4552 if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (name))
4555 if (!extract_code_and_val_from_cond_with_ops (name, cond_code,
4561 /* Register ASSERT_EXPRs for name. */
4562 retval |= register_edge_assert_for_2 (name, e, si, cond_code, cond_op0,
4563 cond_op1, is_else_edge);
4566 /* If COND is effectively an equality test of an SSA_NAME against
4567 the value zero or one, then we may be able to assert values
4568 for SSA_NAMEs which flow into COND. */
4570 /* In the case of NAME == 1 or NAME != 0, for TRUTH_AND_EXPR defining
4571 statement of NAME we can assert both operands of the TRUTH_AND_EXPR
4572 have nonzero value. */
4573 if (((comp_code == EQ_EXPR && integer_onep (val))
4574 || (comp_code == NE_EXPR && integer_zerop (val))))
4576 gimple def_stmt = SSA_NAME_DEF_STMT (name);
4578 if (is_gimple_assign (def_stmt)
4579 && (gimple_assign_rhs_code (def_stmt) == TRUTH_AND_EXPR
4580 || gimple_assign_rhs_code (def_stmt) == BIT_AND_EXPR))
4582 tree op0 = gimple_assign_rhs1 (def_stmt);
4583 tree op1 = gimple_assign_rhs2 (def_stmt);
4584 retval |= register_edge_assert_for_1 (op0, NE_EXPR, e, si);
4585 retval |= register_edge_assert_for_1 (op1, NE_EXPR, e, si);
4589 /* In the case of NAME == 0 or NAME != 1, for TRUTH_OR_EXPR defining
4590 statement of NAME we can assert both operands of the TRUTH_OR_EXPR
4592 if (((comp_code == EQ_EXPR && integer_zerop (val))
4593 || (comp_code == NE_EXPR && integer_onep (val))))
4595 gimple def_stmt = SSA_NAME_DEF_STMT (name);
4597 if (is_gimple_assign (def_stmt)
4598 && (gimple_assign_rhs_code (def_stmt) == TRUTH_OR_EXPR
4599 /* For BIT_IOR_EXPR only if NAME == 0 both operands have
4600 necessarily zero value. */
4601 || (comp_code == EQ_EXPR
4602 && (gimple_assign_rhs_code (def_stmt) == BIT_IOR_EXPR))))
4604 tree op0 = gimple_assign_rhs1 (def_stmt);
4605 tree op1 = gimple_assign_rhs2 (def_stmt);
4606 retval |= register_edge_assert_for_1 (op0, EQ_EXPR, e, si);
4607 retval |= register_edge_assert_for_1 (op1, EQ_EXPR, e, si);
4615 /* Determine whether the outgoing edges of BB should receive an
4616 ASSERT_EXPR for each of the operands of BB's LAST statement.
4617 The last statement of BB must be a COND_EXPR.
4619 If any of the sub-graphs rooted at BB have an interesting use of
4620 the predicate operands, an assert location node is added to the
4621 list of assertions for the corresponding operands. */
4624 find_conditional_asserts (basic_block bb, gimple last)
4627 gimple_stmt_iterator bsi;
4633 need_assert = false;
4634 bsi = gsi_for_stmt (last);
4636 /* Look for uses of the operands in each of the sub-graphs
4637 rooted at BB. We need to check each of the outgoing edges
4638 separately, so that we know what kind of ASSERT_EXPR to
4640 FOR_EACH_EDGE (e, ei, bb->succs)
4645 /* Register the necessary assertions for each operand in the
4646 conditional predicate. */
4647 FOR_EACH_SSA_TREE_OPERAND (op, last, iter, SSA_OP_USE)
4649 need_assert |= register_edge_assert_for (op, e, bsi,
4650 gimple_cond_code (last),
4651 gimple_cond_lhs (last),
4652 gimple_cond_rhs (last));
4659 /* Compare two case labels sorting first by the destination label uid
4660 and then by the case value. */
4663 compare_case_labels (const void *p1, const void *p2)
4665 const_tree const case1 = *(const_tree const*)p1;
4666 const_tree const case2 = *(const_tree const*)p2;
4667 unsigned int uid1 = DECL_UID (CASE_LABEL (case1));
4668 unsigned int uid2 = DECL_UID (CASE_LABEL (case2));
4672 else if (uid1 == uid2)
4674 /* Make sure the default label is first in a group. */
4675 if (!CASE_LOW (case1))
4677 else if (!CASE_LOW (case2))
4680 return tree_int_cst_compare (CASE_LOW (case1), CASE_LOW (case2));
4686 /* Determine whether the outgoing edges of BB should receive an
4687 ASSERT_EXPR for each of the operands of BB's LAST statement.
4688 The last statement of BB must be a SWITCH_EXPR.
4690 If any of the sub-graphs rooted at BB have an interesting use of
4691 the predicate operands, an assert location node is added to the
4692 list of assertions for the corresponding operands. */
4695 find_switch_asserts (basic_block bb, gimple last)
4698 gimple_stmt_iterator bsi;
4702 size_t n = gimple_switch_num_labels(last);
4703 #if GCC_VERSION >= 4000
4706 /* Work around GCC 3.4 bug (PR 37086). */
4707 volatile unsigned int idx;
4710 need_assert = false;
4711 bsi = gsi_for_stmt (last);
4712 op = gimple_switch_index (last);
4713 if (TREE_CODE (op) != SSA_NAME)
4716 /* Build a vector of case labels sorted by destination label. */
4717 vec2 = make_tree_vec (n);
4718 for (idx = 0; idx < n; ++idx)
4719 TREE_VEC_ELT (vec2, idx) = gimple_switch_label (last, idx);
4720 qsort (&TREE_VEC_ELT (vec2, 0), n, sizeof (tree), compare_case_labels);
4722 for (idx = 0; idx < n; ++idx)
4725 tree cl = TREE_VEC_ELT (vec2, idx);
4727 min = CASE_LOW (cl);
4728 max = CASE_HIGH (cl);
4730 /* If there are multiple case labels with the same destination
4731 we need to combine them to a single value range for the edge. */
4733 && CASE_LABEL (cl) == CASE_LABEL (TREE_VEC_ELT (vec2, idx + 1)))
4735 /* Skip labels until the last of the group. */
4739 && CASE_LABEL (cl) == CASE_LABEL (TREE_VEC_ELT (vec2, idx)));
4742 /* Pick up the maximum of the case label range. */
4743 if (CASE_HIGH (TREE_VEC_ELT (vec2, idx)))
4744 max = CASE_HIGH (TREE_VEC_ELT (vec2, idx));
4746 max = CASE_LOW (TREE_VEC_ELT (vec2, idx));
4749 /* Nothing to do if the range includes the default label until we
4750 can register anti-ranges. */
4751 if (min == NULL_TREE)
4754 /* Find the edge to register the assert expr on. */
4755 e = find_edge (bb, label_to_block (CASE_LABEL (cl)));
4757 /* Register the necessary assertions for the operand in the
4759 need_assert |= register_edge_assert_for (op, e, bsi,
4760 max ? GE_EXPR : EQ_EXPR,
4762 fold_convert (TREE_TYPE (op),
4766 need_assert |= register_edge_assert_for (op, e, bsi, LE_EXPR,
4768 fold_convert (TREE_TYPE (op),
4777 /* Traverse all the statements in block BB looking for statements that
4778 may generate useful assertions for the SSA names in their operand.
4779 If a statement produces a useful assertion A for name N_i, then the
4780 list of assertions already generated for N_i is scanned to
4781 determine if A is actually needed.
4783 If N_i already had the assertion A at a location dominating the
4784 current location, then nothing needs to be done. Otherwise, the
4785 new location for A is recorded instead.
4787 1- For every statement S in BB, all the variables used by S are
4788 added to bitmap FOUND_IN_SUBGRAPH.
4790 2- If statement S uses an operand N in a way that exposes a known
4791 value range for N, then if N was not already generated by an
4792 ASSERT_EXPR, create a new assert location for N. For instance,
4793 if N is a pointer and the statement dereferences it, we can
4794 assume that N is not NULL.
4796 3- COND_EXPRs are a special case of #2. We can derive range
4797 information from the predicate but need to insert different
4798 ASSERT_EXPRs for each of the sub-graphs rooted at the
4799 conditional block. If the last statement of BB is a conditional
4800 expression of the form 'X op Y', then
4802 a) Remove X and Y from the set FOUND_IN_SUBGRAPH.
4804 b) If the conditional is the only entry point to the sub-graph
4805 corresponding to the THEN_CLAUSE, recurse into it. On
4806 return, if X and/or Y are marked in FOUND_IN_SUBGRAPH, then
4807 an ASSERT_EXPR is added for the corresponding variable.
4809 c) Repeat step (b) on the ELSE_CLAUSE.
4811 d) Mark X and Y in FOUND_IN_SUBGRAPH.
4820 In this case, an assertion on the THEN clause is useful to
4821 determine that 'a' is always 9 on that edge. However, an assertion
4822 on the ELSE clause would be unnecessary.
4824 4- If BB does not end in a conditional expression, then we recurse
4825 into BB's dominator children.
4827 At the end of the recursive traversal, every SSA name will have a
4828 list of locations where ASSERT_EXPRs should be added. When a new
4829 location for name N is found, it is registered by calling
4830 register_new_assert_for. That function keeps track of all the
4831 registered assertions to prevent adding unnecessary assertions.
4832 For instance, if a pointer P_4 is dereferenced more than once in a
4833 dominator tree, only the location dominating all the dereference of
4834 P_4 will receive an ASSERT_EXPR.
4836 If this function returns true, then it means that there are names
4837 for which we need to generate ASSERT_EXPRs. Those assertions are
4838 inserted by process_assert_insertions. */
4841 find_assert_locations_1 (basic_block bb, sbitmap live)
4843 gimple_stmt_iterator si;
4848 need_assert = false;
4849 last = last_stmt (bb);
4851 /* If BB's last statement is a conditional statement involving integer
4852 operands, determine if we need to add ASSERT_EXPRs. */
4854 && gimple_code (last) == GIMPLE_COND
4855 && !fp_predicate (last)
4856 && !ZERO_SSA_OPERANDS (last, SSA_OP_USE))
4857 need_assert |= find_conditional_asserts (bb, last);
4859 /* If BB's last statement is a switch statement involving integer
4860 operands, determine if we need to add ASSERT_EXPRs. */
4862 && gimple_code (last) == GIMPLE_SWITCH
4863 && !ZERO_SSA_OPERANDS (last, SSA_OP_USE))
4864 need_assert |= find_switch_asserts (bb, last);
4866 /* Traverse all the statements in BB marking used names and looking
4867 for statements that may infer assertions for their used operands. */
4868 for (si = gsi_start_bb (bb); !gsi_end_p (si); gsi_next (&si))
4874 stmt = gsi_stmt (si);
4876 if (is_gimple_debug (stmt))
4879 /* See if we can derive an assertion for any of STMT's operands. */
4880 FOR_EACH_SSA_TREE_OPERAND (op, stmt, i, SSA_OP_USE)
4883 enum tree_code comp_code;
4885 /* Mark OP in our live bitmap. */
4886 SET_BIT (live, SSA_NAME_VERSION (op));
4888 /* If OP is used in such a way that we can infer a value
4889 range for it, and we don't find a previous assertion for
4890 it, create a new assertion location node for OP. */
4891 if (infer_value_range (stmt, op, &comp_code, &value))
4893 /* If we are able to infer a nonzero value range for OP,
4894 then walk backwards through the use-def chain to see if OP
4895 was set via a typecast.
4897 If so, then we can also infer a nonzero value range
4898 for the operand of the NOP_EXPR. */
4899 if (comp_code == NE_EXPR && integer_zerop (value))
4902 gimple def_stmt = SSA_NAME_DEF_STMT (t);
4904 while (is_gimple_assign (def_stmt)
4905 && gimple_assign_rhs_code (def_stmt) == NOP_EXPR
4907 (gimple_assign_rhs1 (def_stmt)) == SSA_NAME
4909 (TREE_TYPE (gimple_assign_rhs1 (def_stmt))))
4911 t = gimple_assign_rhs1 (def_stmt);
4912 def_stmt = SSA_NAME_DEF_STMT (t);
4914 /* Note we want to register the assert for the
4915 operand of the NOP_EXPR after SI, not after the
4917 if (! has_single_use (t))
4919 register_new_assert_for (t, t, comp_code, value,
4926 /* If OP is used only once, namely in this STMT, don't
4927 bother creating an ASSERT_EXPR for it. Such an
4928 ASSERT_EXPR would do nothing but increase compile time. */
4929 if (!has_single_use (op))
4931 register_new_assert_for (op, op, comp_code, value,
4939 /* Traverse all PHI nodes in BB marking used operands. */
4940 for (si = gsi_start_phis (bb); !gsi_end_p(si); gsi_next (&si))
4942 use_operand_p arg_p;
4944 phi = gsi_stmt (si);
4946 FOR_EACH_PHI_ARG (arg_p, phi, i, SSA_OP_USE)
4948 tree arg = USE_FROM_PTR (arg_p);
4949 if (TREE_CODE (arg) == SSA_NAME)
4950 SET_BIT (live, SSA_NAME_VERSION (arg));
4957 /* Do an RPO walk over the function computing SSA name liveness
4958 on-the-fly and deciding on assert expressions to insert.
4959 Returns true if there are assert expressions to be inserted. */
4962 find_assert_locations (void)
4964 int *rpo = XCNEWVEC (int, last_basic_block + NUM_FIXED_BLOCKS);
4965 int *bb_rpo = XCNEWVEC (int, last_basic_block + NUM_FIXED_BLOCKS);
4966 int *last_rpo = XCNEWVEC (int, last_basic_block + NUM_FIXED_BLOCKS);
4970 live = XCNEWVEC (sbitmap, last_basic_block + NUM_FIXED_BLOCKS);
4971 rpo_cnt = pre_and_rev_post_order_compute (NULL, rpo, false);
4972 for (i = 0; i < rpo_cnt; ++i)
4975 need_asserts = false;
4976 for (i = rpo_cnt-1; i >= 0; --i)
4978 basic_block bb = BASIC_BLOCK (rpo[i]);
4984 live[rpo[i]] = sbitmap_alloc (num_ssa_names);
4985 sbitmap_zero (live[rpo[i]]);
4988 /* Process BB and update the live information with uses in
4990 need_asserts |= find_assert_locations_1 (bb, live[rpo[i]]);
4992 /* Merge liveness into the predecessor blocks and free it. */
4993 if (!sbitmap_empty_p (live[rpo[i]]))
4996 FOR_EACH_EDGE (e, ei, bb->preds)
4998 int pred = e->src->index;
4999 if (e->flags & EDGE_DFS_BACK)
5004 live[pred] = sbitmap_alloc (num_ssa_names);
5005 sbitmap_zero (live[pred]);
5007 sbitmap_a_or_b (live[pred], live[pred], live[rpo[i]]);
5009 if (bb_rpo[pred] < pred_rpo)
5010 pred_rpo = bb_rpo[pred];
5013 /* Record the RPO number of the last visited block that needs
5014 live information from this block. */
5015 last_rpo[rpo[i]] = pred_rpo;
5019 sbitmap_free (live[rpo[i]]);
5020 live[rpo[i]] = NULL;
5023 /* We can free all successors live bitmaps if all their
5024 predecessors have been visited already. */
5025 FOR_EACH_EDGE (e, ei, bb->succs)
5026 if (last_rpo[e->dest->index] == i
5027 && live[e->dest->index])
5029 sbitmap_free (live[e->dest->index]);
5030 live[e->dest->index] = NULL;
5035 XDELETEVEC (bb_rpo);
5036 XDELETEVEC (last_rpo);
5037 for (i = 0; i < last_basic_block + NUM_FIXED_BLOCKS; ++i)
5039 sbitmap_free (live[i]);
5042 return need_asserts;
5045 /* Create an ASSERT_EXPR for NAME and insert it in the location
5046 indicated by LOC. Return true if we made any edge insertions. */
5049 process_assert_insertions_for (tree name, assert_locus_t loc)
5051 /* Build the comparison expression NAME_i COMP_CODE VAL. */
5058 /* If we have X <=> X do not insert an assert expr for that. */
5059 if (loc->expr == loc->val)
5062 cond = build2 (loc->comp_code, boolean_type_node, loc->expr, loc->val);
5063 assert_stmt = build_assert_expr_for (cond, name);
5066 /* We have been asked to insert the assertion on an edge. This
5067 is used only by COND_EXPR and SWITCH_EXPR assertions. */
5068 gcc_checking_assert (gimple_code (gsi_stmt (loc->si)) == GIMPLE_COND
5069 || (gimple_code (gsi_stmt (loc->si))
5072 gsi_insert_on_edge (loc->e, assert_stmt);
5076 /* Otherwise, we can insert right after LOC->SI iff the
5077 statement must not be the last statement in the block. */
5078 stmt = gsi_stmt (loc->si);
5079 if (!stmt_ends_bb_p (stmt))
5081 gsi_insert_after (&loc->si, assert_stmt, GSI_SAME_STMT);
5085 /* If STMT must be the last statement in BB, we can only insert new
5086 assertions on the non-abnormal edge out of BB. Note that since
5087 STMT is not control flow, there may only be one non-abnormal edge
5089 FOR_EACH_EDGE (e, ei, loc->bb->succs)
5090 if (!(e->flags & EDGE_ABNORMAL))
5092 gsi_insert_on_edge (e, assert_stmt);
5100 /* Process all the insertions registered for every name N_i registered
5101 in NEED_ASSERT_FOR. The list of assertions to be inserted are
5102 found in ASSERTS_FOR[i]. */
5105 process_assert_insertions (void)
5109 bool update_edges_p = false;
5110 int num_asserts = 0;
5112 if (dump_file && (dump_flags & TDF_DETAILS))
5113 dump_all_asserts (dump_file);
5115 EXECUTE_IF_SET_IN_BITMAP (need_assert_for, 0, i, bi)
5117 assert_locus_t loc = asserts_for[i];
5122 assert_locus_t next = loc->next;
5123 update_edges_p |= process_assert_insertions_for (ssa_name (i), loc);
5131 gsi_commit_edge_inserts ();
5133 statistics_counter_event (cfun, "Number of ASSERT_EXPR expressions inserted",
5138 /* Traverse the flowgraph looking for conditional jumps to insert range
5139 expressions. These range expressions are meant to provide information
5140 to optimizations that need to reason in terms of value ranges. They
5141 will not be expanded into RTL. For instance, given:
5150 this pass will transform the code into:
5156 x = ASSERT_EXPR <x, x < y>
5161 y = ASSERT_EXPR <y, x <= y>
5165 The idea is that once copy and constant propagation have run, other
5166 optimizations will be able to determine what ranges of values can 'x'
5167 take in different paths of the code, simply by checking the reaching
5168 definition of 'x'. */
5171 insert_range_assertions (void)
5173 need_assert_for = BITMAP_ALLOC (NULL);
5174 asserts_for = XCNEWVEC (assert_locus_t, num_ssa_names);
5176 calculate_dominance_info (CDI_DOMINATORS);
5178 if (find_assert_locations ())
5180 process_assert_insertions ();
5181 update_ssa (TODO_update_ssa_no_phi);
5184 if (dump_file && (dump_flags & TDF_DETAILS))
5186 fprintf (dump_file, "\nSSA form after inserting ASSERT_EXPRs\n");
5187 dump_function_to_file (current_function_decl, dump_file, dump_flags);
5191 BITMAP_FREE (need_assert_for);
5194 /* Checks one ARRAY_REF in REF, located at LOCUS. Ignores flexible arrays
5195 and "struct" hacks. If VRP can determine that the
5196 array subscript is a constant, check if it is outside valid
5197 range. If the array subscript is a RANGE, warn if it is
5198 non-overlapping with valid range.
5199 IGNORE_OFF_BY_ONE is true if the ARRAY_REF is inside a ADDR_EXPR. */
5202 check_array_ref (location_t location, tree ref, bool ignore_off_by_one)
5204 value_range_t* vr = NULL;
5205 tree low_sub, up_sub;
5206 tree low_bound, up_bound, up_bound_p1;
5209 if (TREE_NO_WARNING (ref))
5212 low_sub = up_sub = TREE_OPERAND (ref, 1);
5213 up_bound = array_ref_up_bound (ref);
5215 /* Can not check flexible arrays. */
5217 || TREE_CODE (up_bound) != INTEGER_CST)
5220 /* Accesses to trailing arrays via pointers may access storage
5221 beyond the types array bounds. */
5222 base = get_base_address (ref);
5223 if (base && TREE_CODE (base) == MEM_REF)
5225 tree cref, next = NULL_TREE;
5227 if (TREE_CODE (TREE_OPERAND (ref, 0)) != COMPONENT_REF)
5230 cref = TREE_OPERAND (ref, 0);
5231 if (TREE_CODE (TREE_TYPE (TREE_OPERAND (cref, 0))) == RECORD_TYPE)
5232 for (next = DECL_CHAIN (TREE_OPERAND (cref, 1));
5233 next && TREE_CODE (next) != FIELD_DECL;
5234 next = DECL_CHAIN (next))
5237 /* If this is the last field in a struct type or a field in a
5238 union type do not warn. */
5243 low_bound = array_ref_low_bound (ref);
5244 up_bound_p1 = int_const_binop (PLUS_EXPR, up_bound, integer_one_node, 0);
5246 if (TREE_CODE (low_sub) == SSA_NAME)
5248 vr = get_value_range (low_sub);
5249 if (vr->type == VR_RANGE || vr->type == VR_ANTI_RANGE)
5251 low_sub = vr->type == VR_RANGE ? vr->max : vr->min;
5252 up_sub = vr->type == VR_RANGE ? vr->min : vr->max;
5256 if (vr && vr->type == VR_ANTI_RANGE)
5258 if (TREE_CODE (up_sub) == INTEGER_CST
5259 && tree_int_cst_lt (up_bound, up_sub)
5260 && TREE_CODE (low_sub) == INTEGER_CST
5261 && tree_int_cst_lt (low_sub, low_bound))
5263 warning_at (location, OPT_Warray_bounds,
5264 "array subscript is outside array bounds");
5265 TREE_NO_WARNING (ref) = 1;
5268 else if (TREE_CODE (up_sub) == INTEGER_CST
5269 && (ignore_off_by_one
5270 ? (tree_int_cst_lt (up_bound, up_sub)
5271 && !tree_int_cst_equal (up_bound_p1, up_sub))
5272 : (tree_int_cst_lt (up_bound, up_sub)
5273 || tree_int_cst_equal (up_bound_p1, up_sub))))
5275 warning_at (location, OPT_Warray_bounds,
5276 "array subscript is above array bounds");
5277 TREE_NO_WARNING (ref) = 1;
5279 else if (TREE_CODE (low_sub) == INTEGER_CST
5280 && tree_int_cst_lt (low_sub, low_bound))
5282 warning_at (location, OPT_Warray_bounds,
5283 "array subscript is below array bounds");
5284 TREE_NO_WARNING (ref) = 1;
5288 /* Searches if the expr T, located at LOCATION computes
5289 address of an ARRAY_REF, and call check_array_ref on it. */
5292 search_for_addr_array (tree t, location_t location)
5294 while (TREE_CODE (t) == SSA_NAME)
5296 gimple g = SSA_NAME_DEF_STMT (t);
5298 if (gimple_code (g) != GIMPLE_ASSIGN)
5301 if (get_gimple_rhs_class (gimple_assign_rhs_code (g))
5302 != GIMPLE_SINGLE_RHS)
5305 t = gimple_assign_rhs1 (g);
5309 /* We are only interested in addresses of ARRAY_REF's. */
5310 if (TREE_CODE (t) != ADDR_EXPR)
5313 /* Check each ARRAY_REFs in the reference chain. */
5316 if (TREE_CODE (t) == ARRAY_REF)
5317 check_array_ref (location, t, true /*ignore_off_by_one*/);
5319 t = TREE_OPERAND (t, 0);
5321 while (handled_component_p (t));
5323 if (TREE_CODE (t) == MEM_REF
5324 && TREE_CODE (TREE_OPERAND (t, 0)) == ADDR_EXPR
5325 && !TREE_NO_WARNING (t))
5327 tree tem = TREE_OPERAND (TREE_OPERAND (t, 0), 0);
5328 tree low_bound, up_bound, el_sz;
5330 if (TREE_CODE (TREE_TYPE (tem)) != ARRAY_TYPE
5331 || TREE_CODE (TREE_TYPE (TREE_TYPE (tem))) == ARRAY_TYPE
5332 || !TYPE_DOMAIN (TREE_TYPE (tem)))
5335 low_bound = TYPE_MIN_VALUE (TYPE_DOMAIN (TREE_TYPE (tem)));
5336 up_bound = TYPE_MAX_VALUE (TYPE_DOMAIN (TREE_TYPE (tem)));
5337 el_sz = TYPE_SIZE_UNIT (TREE_TYPE (TREE_TYPE (tem)));
5339 || TREE_CODE (low_bound) != INTEGER_CST
5341 || TREE_CODE (up_bound) != INTEGER_CST
5343 || TREE_CODE (el_sz) != INTEGER_CST)
5346 idx = mem_ref_offset (t);
5347 idx = double_int_sdiv (idx, tree_to_double_int (el_sz), TRUNC_DIV_EXPR);
5348 if (double_int_scmp (idx, double_int_zero) < 0)
5350 warning_at (location, OPT_Warray_bounds,
5351 "array subscript is below array bounds");
5352 TREE_NO_WARNING (t) = 1;
5354 else if (double_int_scmp (idx,
5357 (tree_to_double_int (up_bound),
5359 (tree_to_double_int (low_bound))),
5360 double_int_one)) > 0)
5362 warning_at (location, OPT_Warray_bounds,
5363 "array subscript is above array bounds");
5364 TREE_NO_WARNING (t) = 1;
5369 /* walk_tree() callback that checks if *TP is
5370 an ARRAY_REF inside an ADDR_EXPR (in which an array
5371 subscript one outside the valid range is allowed). Call
5372 check_array_ref for each ARRAY_REF found. The location is
5376 check_array_bounds (tree *tp, int *walk_subtree, void *data)
5379 struct walk_stmt_info *wi = (struct walk_stmt_info *) data;
5380 location_t location;
5382 if (EXPR_HAS_LOCATION (t))
5383 location = EXPR_LOCATION (t);
5386 location_t *locp = (location_t *) wi->info;
5390 *walk_subtree = TRUE;
5392 if (TREE_CODE (t) == ARRAY_REF)
5393 check_array_ref (location, t, false /*ignore_off_by_one*/);
5395 if (TREE_CODE (t) == MEM_REF
5396 || (TREE_CODE (t) == RETURN_EXPR && TREE_OPERAND (t, 0)))
5397 search_for_addr_array (TREE_OPERAND (t, 0), location);
5399 if (TREE_CODE (t) == ADDR_EXPR)
5400 *walk_subtree = FALSE;
5405 /* Walk over all statements of all reachable BBs and call check_array_bounds
5409 check_all_array_refs (void)
5412 gimple_stmt_iterator si;
5418 bool executable = false;
5420 /* Skip blocks that were found to be unreachable. */
5421 FOR_EACH_EDGE (e, ei, bb->preds)
5422 executable |= !!(e->flags & EDGE_EXECUTABLE);
5426 for (si = gsi_start_bb (bb); !gsi_end_p (si); gsi_next (&si))
5428 gimple stmt = gsi_stmt (si);
5429 struct walk_stmt_info wi;
5430 if (!gimple_has_location (stmt))
5433 if (is_gimple_call (stmt))
5436 size_t n = gimple_call_num_args (stmt);
5437 for (i = 0; i < n; i++)
5439 tree arg = gimple_call_arg (stmt, i);
5440 search_for_addr_array (arg, gimple_location (stmt));
5445 memset (&wi, 0, sizeof (wi));
5446 wi.info = CONST_CAST (void *, (const void *)
5447 gimple_location_ptr (stmt));
5449 walk_gimple_op (gsi_stmt (si),
5457 /* Convert range assertion expressions into the implied copies and
5458 copy propagate away the copies. Doing the trivial copy propagation
5459 here avoids the need to run the full copy propagation pass after
5462 FIXME, this will eventually lead to copy propagation removing the
5463 names that had useful range information attached to them. For
5464 instance, if we had the assertion N_i = ASSERT_EXPR <N_j, N_j > 3>,
5465 then N_i will have the range [3, +INF].
5467 However, by converting the assertion into the implied copy
5468 operation N_i = N_j, we will then copy-propagate N_j into the uses
5469 of N_i and lose the range information. We may want to hold on to
5470 ASSERT_EXPRs a little while longer as the ranges could be used in
5471 things like jump threading.
5473 The problem with keeping ASSERT_EXPRs around is that passes after
5474 VRP need to handle them appropriately.
5476 Another approach would be to make the range information a first
5477 class property of the SSA_NAME so that it can be queried from
5478 any pass. This is made somewhat more complex by the need for
5479 multiple ranges to be associated with one SSA_NAME. */
5482 remove_range_assertions (void)
5485 gimple_stmt_iterator si;
5487 /* Note that the BSI iterator bump happens at the bottom of the
5488 loop and no bump is necessary if we're removing the statement
5489 referenced by the current BSI. */
5491 for (si = gsi_start_bb (bb); !gsi_end_p (si);)
5493 gimple stmt = gsi_stmt (si);
5496 if (is_gimple_assign (stmt)
5497 && gimple_assign_rhs_code (stmt) == ASSERT_EXPR)
5499 tree rhs = gimple_assign_rhs1 (stmt);
5501 tree cond = fold (ASSERT_EXPR_COND (rhs));
5502 use_operand_p use_p;
5503 imm_use_iterator iter;
5505 gcc_assert (cond != boolean_false_node);
5507 /* Propagate the RHS into every use of the LHS. */
5508 var = ASSERT_EXPR_VAR (rhs);
5509 FOR_EACH_IMM_USE_STMT (use_stmt, iter,
5510 gimple_assign_lhs (stmt))
5511 FOR_EACH_IMM_USE_ON_STMT (use_p, iter)
5513 SET_USE (use_p, var);
5514 gcc_assert (TREE_CODE (var) == SSA_NAME);
5517 /* And finally, remove the copy, it is not needed. */
5518 gsi_remove (&si, true);
5519 release_defs (stmt);
5527 /* Return true if STMT is interesting for VRP. */
5530 stmt_interesting_for_vrp (gimple stmt)
5532 if (gimple_code (stmt) == GIMPLE_PHI
5533 && is_gimple_reg (gimple_phi_result (stmt))
5534 && (INTEGRAL_TYPE_P (TREE_TYPE (gimple_phi_result (stmt)))
5535 || POINTER_TYPE_P (TREE_TYPE (gimple_phi_result (stmt)))))
5537 else if (is_gimple_assign (stmt) || is_gimple_call (stmt))
5539 tree lhs = gimple_get_lhs (stmt);
5541 /* In general, assignments with virtual operands are not useful
5542 for deriving ranges, with the obvious exception of calls to
5543 builtin functions. */
5544 if (lhs && TREE_CODE (lhs) == SSA_NAME
5545 && (INTEGRAL_TYPE_P (TREE_TYPE (lhs))
5546 || POINTER_TYPE_P (TREE_TYPE (lhs)))
5547 && ((is_gimple_call (stmt)
5548 && gimple_call_fndecl (stmt) != NULL_TREE
5549 && DECL_IS_BUILTIN (gimple_call_fndecl (stmt)))
5550 || !gimple_vuse (stmt)))
5553 else if (gimple_code (stmt) == GIMPLE_COND
5554 || gimple_code (stmt) == GIMPLE_SWITCH)
5561 /* Initialize local data structures for VRP. */
5564 vrp_initialize (void)
5568 vr_value = XCNEWVEC (value_range_t *, num_ssa_names);
5569 vr_phi_edge_counts = XCNEWVEC (int, num_ssa_names);
5573 gimple_stmt_iterator si;
5575 for (si = gsi_start_phis (bb); !gsi_end_p (si); gsi_next (&si))
5577 gimple phi = gsi_stmt (si);
5578 if (!stmt_interesting_for_vrp (phi))
5580 tree lhs = PHI_RESULT (phi);
5581 set_value_range_to_varying (get_value_range (lhs));
5582 prop_set_simulate_again (phi, false);
5585 prop_set_simulate_again (phi, true);
5588 for (si = gsi_start_bb (bb); !gsi_end_p (si); gsi_next (&si))
5590 gimple stmt = gsi_stmt (si);
5592 /* If the statement is a control insn, then we do not
5593 want to avoid simulating the statement once. Failure
5594 to do so means that those edges will never get added. */
5595 if (stmt_ends_bb_p (stmt))
5596 prop_set_simulate_again (stmt, true);
5597 else if (!stmt_interesting_for_vrp (stmt))
5601 FOR_EACH_SSA_TREE_OPERAND (def, stmt, i, SSA_OP_DEF)
5602 set_value_range_to_varying (get_value_range (def));
5603 prop_set_simulate_again (stmt, false);
5606 prop_set_simulate_again (stmt, true);
5612 /* Visit assignment STMT. If it produces an interesting range, record
5613 the SSA name in *OUTPUT_P. */
5615 static enum ssa_prop_result
5616 vrp_visit_assignment_or_call (gimple stmt, tree *output_p)
5620 enum gimple_code code = gimple_code (stmt);
5621 lhs = gimple_get_lhs (stmt);
5623 /* We only keep track of ranges in integral and pointer types. */
5624 if (TREE_CODE (lhs) == SSA_NAME
5625 && ((INTEGRAL_TYPE_P (TREE_TYPE (lhs))
5626 /* It is valid to have NULL MIN/MAX values on a type. See
5627 build_range_type. */
5628 && TYPE_MIN_VALUE (TREE_TYPE (lhs))
5629 && TYPE_MAX_VALUE (TREE_TYPE (lhs)))
5630 || POINTER_TYPE_P (TREE_TYPE (lhs))))
5632 value_range_t new_vr = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
5634 if (code == GIMPLE_CALL)
5635 extract_range_basic (&new_vr, stmt);
5637 extract_range_from_assignment (&new_vr, stmt);
5639 if (update_value_range (lhs, &new_vr))
5643 if (dump_file && (dump_flags & TDF_DETAILS))
5645 fprintf (dump_file, "Found new range for ");
5646 print_generic_expr (dump_file, lhs, 0);
5647 fprintf (dump_file, ": ");
5648 dump_value_range (dump_file, &new_vr);
5649 fprintf (dump_file, "\n\n");
5652 if (new_vr.type == VR_VARYING)
5653 return SSA_PROP_VARYING;
5655 return SSA_PROP_INTERESTING;
5658 return SSA_PROP_NOT_INTERESTING;
5661 /* Every other statement produces no useful ranges. */
5662 FOR_EACH_SSA_TREE_OPERAND (def, stmt, iter, SSA_OP_DEF)
5663 set_value_range_to_varying (get_value_range (def));
5665 return SSA_PROP_VARYING;
5668 /* Helper that gets the value range of the SSA_NAME with version I
5669 or a symbolic range containing the SSA_NAME only if the value range
5670 is varying or undefined. */
5672 static inline value_range_t
5673 get_vr_for_comparison (int i)
5675 value_range_t vr = *(vr_value[i]);
5677 /* If name N_i does not have a valid range, use N_i as its own
5678 range. This allows us to compare against names that may
5679 have N_i in their ranges. */
5680 if (vr.type == VR_VARYING || vr.type == VR_UNDEFINED)
5683 vr.min = ssa_name (i);
5684 vr.max = ssa_name (i);
5690 /* Compare all the value ranges for names equivalent to VAR with VAL
5691 using comparison code COMP. Return the same value returned by
5692 compare_range_with_value, including the setting of
5693 *STRICT_OVERFLOW_P. */
5696 compare_name_with_value (enum tree_code comp, tree var, tree val,
5697 bool *strict_overflow_p)
5703 int used_strict_overflow;
5705 value_range_t equiv_vr;
5707 /* Get the set of equivalences for VAR. */
5708 e = get_value_range (var)->equiv;
5710 /* Start at -1. Set it to 0 if we do a comparison without relying
5711 on overflow, or 1 if all comparisons rely on overflow. */
5712 used_strict_overflow = -1;
5714 /* Compare vars' value range with val. */
5715 equiv_vr = get_vr_for_comparison (SSA_NAME_VERSION (var));
5717 retval = compare_range_with_value (comp, &equiv_vr, val, &sop);
5719 used_strict_overflow = sop ? 1 : 0;
5721 /* If the equiv set is empty we have done all work we need to do. */
5725 && used_strict_overflow > 0)
5726 *strict_overflow_p = true;
5730 EXECUTE_IF_SET_IN_BITMAP (e, 0, i, bi)
5732 equiv_vr = get_vr_for_comparison (i);
5734 t = compare_range_with_value (comp, &equiv_vr, val, &sop);
5737 /* If we get different answers from different members
5738 of the equivalence set this check must be in a dead
5739 code region. Folding it to a trap representation
5740 would be correct here. For now just return don't-know. */
5750 used_strict_overflow = 0;
5751 else if (used_strict_overflow < 0)
5752 used_strict_overflow = 1;
5757 && used_strict_overflow > 0)
5758 *strict_overflow_p = true;
5764 /* Given a comparison code COMP and names N1 and N2, compare all the
5765 ranges equivalent to N1 against all the ranges equivalent to N2
5766 to determine the value of N1 COMP N2. Return the same value
5767 returned by compare_ranges. Set *STRICT_OVERFLOW_P to indicate
5768 whether we relied on an overflow infinity in the comparison. */
5772 compare_names (enum tree_code comp, tree n1, tree n2,
5773 bool *strict_overflow_p)
5777 bitmap_iterator bi1, bi2;
5779 int used_strict_overflow;
5780 static bitmap_obstack *s_obstack = NULL;
5781 static bitmap s_e1 = NULL, s_e2 = NULL;
5783 /* Compare the ranges of every name equivalent to N1 against the
5784 ranges of every name equivalent to N2. */
5785 e1 = get_value_range (n1)->equiv;
5786 e2 = get_value_range (n2)->equiv;
5788 /* Use the fake bitmaps if e1 or e2 are not available. */
5789 if (s_obstack == NULL)
5791 s_obstack = XNEW (bitmap_obstack);
5792 bitmap_obstack_initialize (s_obstack);
5793 s_e1 = BITMAP_ALLOC (s_obstack);
5794 s_e2 = BITMAP_ALLOC (s_obstack);
5801 /* Add N1 and N2 to their own set of equivalences to avoid
5802 duplicating the body of the loop just to check N1 and N2
5804 bitmap_set_bit (e1, SSA_NAME_VERSION (n1));
5805 bitmap_set_bit (e2, SSA_NAME_VERSION (n2));
5807 /* If the equivalence sets have a common intersection, then the two
5808 names can be compared without checking their ranges. */
5809 if (bitmap_intersect_p (e1, e2))
5811 bitmap_clear_bit (e1, SSA_NAME_VERSION (n1));
5812 bitmap_clear_bit (e2, SSA_NAME_VERSION (n2));
5814 return (comp == EQ_EXPR || comp == GE_EXPR || comp == LE_EXPR)
5816 : boolean_false_node;
5819 /* Start at -1. Set it to 0 if we do a comparison without relying
5820 on overflow, or 1 if all comparisons rely on overflow. */
5821 used_strict_overflow = -1;
5823 /* Otherwise, compare all the equivalent ranges. First, add N1 and
5824 N2 to their own set of equivalences to avoid duplicating the body
5825 of the loop just to check N1 and N2 ranges. */
5826 EXECUTE_IF_SET_IN_BITMAP (e1, 0, i1, bi1)
5828 value_range_t vr1 = get_vr_for_comparison (i1);
5830 t = retval = NULL_TREE;
5831 EXECUTE_IF_SET_IN_BITMAP (e2, 0, i2, bi2)
5835 value_range_t vr2 = get_vr_for_comparison (i2);
5837 t = compare_ranges (comp, &vr1, &vr2, &sop);
5840 /* If we get different answers from different members
5841 of the equivalence set this check must be in a dead
5842 code region. Folding it to a trap representation
5843 would be correct here. For now just return don't-know. */
5847 bitmap_clear_bit (e1, SSA_NAME_VERSION (n1));
5848 bitmap_clear_bit (e2, SSA_NAME_VERSION (n2));
5854 used_strict_overflow = 0;
5855 else if (used_strict_overflow < 0)
5856 used_strict_overflow = 1;
5862 bitmap_clear_bit (e1, SSA_NAME_VERSION (n1));
5863 bitmap_clear_bit (e2, SSA_NAME_VERSION (n2));
5864 if (used_strict_overflow > 0)
5865 *strict_overflow_p = true;
5870 /* None of the equivalent ranges are useful in computing this
5872 bitmap_clear_bit (e1, SSA_NAME_VERSION (n1));
5873 bitmap_clear_bit (e2, SSA_NAME_VERSION (n2));
5877 /* Helper function for vrp_evaluate_conditional_warnv. */
5880 vrp_evaluate_conditional_warnv_with_ops_using_ranges (enum tree_code code,
5882 bool * strict_overflow_p)
5884 value_range_t *vr0, *vr1;
5886 vr0 = (TREE_CODE (op0) == SSA_NAME) ? get_value_range (op0) : NULL;
5887 vr1 = (TREE_CODE (op1) == SSA_NAME) ? get_value_range (op1) : NULL;
5890 return compare_ranges (code, vr0, vr1, strict_overflow_p);
5891 else if (vr0 && vr1 == NULL)
5892 return compare_range_with_value (code, vr0, op1, strict_overflow_p);
5893 else if (vr0 == NULL && vr1)
5894 return (compare_range_with_value
5895 (swap_tree_comparison (code), vr1, op0, strict_overflow_p));
5899 /* Helper function for vrp_evaluate_conditional_warnv. */
5902 vrp_evaluate_conditional_warnv_with_ops (enum tree_code code, tree op0,
5903 tree op1, bool use_equiv_p,
5904 bool *strict_overflow_p, bool *only_ranges)
5908 *only_ranges = true;
5910 /* We only deal with integral and pointer types. */
5911 if (!INTEGRAL_TYPE_P (TREE_TYPE (op0))
5912 && !POINTER_TYPE_P (TREE_TYPE (op0)))
5918 && (ret = vrp_evaluate_conditional_warnv_with_ops_using_ranges
5919 (code, op0, op1, strict_overflow_p)))
5921 *only_ranges = false;
5922 if (TREE_CODE (op0) == SSA_NAME && TREE_CODE (op1) == SSA_NAME)
5923 return compare_names (code, op0, op1, strict_overflow_p);
5924 else if (TREE_CODE (op0) == SSA_NAME)
5925 return compare_name_with_value (code, op0, op1, strict_overflow_p);
5926 else if (TREE_CODE (op1) == SSA_NAME)
5927 return (compare_name_with_value
5928 (swap_tree_comparison (code), op1, op0, strict_overflow_p));
5931 return vrp_evaluate_conditional_warnv_with_ops_using_ranges (code, op0, op1,
5936 /* Given (CODE OP0 OP1) within STMT, try to simplify it based on value range
5937 information. Return NULL if the conditional can not be evaluated.
5938 The ranges of all the names equivalent with the operands in COND
5939 will be used when trying to compute the value. If the result is
5940 based on undefined signed overflow, issue a warning if
5944 vrp_evaluate_conditional (enum tree_code code, tree op0, tree op1, gimple stmt)
5950 /* Some passes and foldings leak constants with overflow flag set
5951 into the IL. Avoid doing wrong things with these and bail out. */
5952 if ((TREE_CODE (op0) == INTEGER_CST
5953 && TREE_OVERFLOW (op0))
5954 || (TREE_CODE (op1) == INTEGER_CST
5955 && TREE_OVERFLOW (op1)))
5959 ret = vrp_evaluate_conditional_warnv_with_ops (code, op0, op1, true, &sop,
5964 enum warn_strict_overflow_code wc;
5965 const char* warnmsg;
5967 if (is_gimple_min_invariant (ret))
5969 wc = WARN_STRICT_OVERFLOW_CONDITIONAL;
5970 warnmsg = G_("assuming signed overflow does not occur when "
5971 "simplifying conditional to constant");
5975 wc = WARN_STRICT_OVERFLOW_COMPARISON;
5976 warnmsg = G_("assuming signed overflow does not occur when "
5977 "simplifying conditional");
5980 if (issue_strict_overflow_warning (wc))
5982 location_t location;
5984 if (!gimple_has_location (stmt))
5985 location = input_location;
5987 location = gimple_location (stmt);
5988 warning_at (location, OPT_Wstrict_overflow, "%s", warnmsg);
5992 if (warn_type_limits
5993 && ret && only_ranges
5994 && TREE_CODE_CLASS (code) == tcc_comparison
5995 && TREE_CODE (op0) == SSA_NAME)
5997 /* If the comparison is being folded and the operand on the LHS
5998 is being compared against a constant value that is outside of
5999 the natural range of OP0's type, then the predicate will
6000 always fold regardless of the value of OP0. If -Wtype-limits
6001 was specified, emit a warning. */
6002 tree type = TREE_TYPE (op0);
6003 value_range_t *vr0 = get_value_range (op0);
6005 if (vr0->type != VR_VARYING
6006 && INTEGRAL_TYPE_P (type)
6007 && vrp_val_is_min (vr0->min)
6008 && vrp_val_is_max (vr0->max)
6009 && is_gimple_min_invariant (op1))
6011 location_t location;
6013 if (!gimple_has_location (stmt))
6014 location = input_location;
6016 location = gimple_location (stmt);
6018 warning_at (location, OPT_Wtype_limits,
6020 ? G_("comparison always false "
6021 "due to limited range of data type")
6022 : G_("comparison always true "
6023 "due to limited range of data type"));
6031 /* Visit conditional statement STMT. If we can determine which edge
6032 will be taken out of STMT's basic block, record it in
6033 *TAKEN_EDGE_P and return SSA_PROP_INTERESTING. Otherwise, return
6034 SSA_PROP_VARYING. */
6036 static enum ssa_prop_result
6037 vrp_visit_cond_stmt (gimple stmt, edge *taken_edge_p)
6042 *taken_edge_p = NULL;
6044 if (dump_file && (dump_flags & TDF_DETAILS))
6049 fprintf (dump_file, "\nVisiting conditional with predicate: ");
6050 print_gimple_stmt (dump_file, stmt, 0, 0);
6051 fprintf (dump_file, "\nWith known ranges\n");
6053 FOR_EACH_SSA_TREE_OPERAND (use, stmt, i, SSA_OP_USE)
6055 fprintf (dump_file, "\t");
6056 print_generic_expr (dump_file, use, 0);
6057 fprintf (dump_file, ": ");
6058 dump_value_range (dump_file, vr_value[SSA_NAME_VERSION (use)]);
6061 fprintf (dump_file, "\n");
6064 /* Compute the value of the predicate COND by checking the known
6065 ranges of each of its operands.
6067 Note that we cannot evaluate all the equivalent ranges here
6068 because those ranges may not yet be final and with the current
6069 propagation strategy, we cannot determine when the value ranges
6070 of the names in the equivalence set have changed.
6072 For instance, given the following code fragment
6076 i_14 = ASSERT_EXPR <i_5, i_5 != 0>
6080 Assume that on the first visit to i_14, i_5 has the temporary
6081 range [8, 8] because the second argument to the PHI function is
6082 not yet executable. We derive the range ~[0, 0] for i_14 and the
6083 equivalence set { i_5 }. So, when we visit 'if (i_14 == 1)' for
6084 the first time, since i_14 is equivalent to the range [8, 8], we
6085 determine that the predicate is always false.
6087 On the next round of propagation, i_13 is determined to be
6088 VARYING, which causes i_5 to drop down to VARYING. So, another
6089 visit to i_14 is scheduled. In this second visit, we compute the
6090 exact same range and equivalence set for i_14, namely ~[0, 0] and
6091 { i_5 }. But we did not have the previous range for i_5
6092 registered, so vrp_visit_assignment thinks that the range for
6093 i_14 has not changed. Therefore, the predicate 'if (i_14 == 1)'
6094 is not visited again, which stops propagation from visiting
6095 statements in the THEN clause of that if().
6097 To properly fix this we would need to keep the previous range
6098 value for the names in the equivalence set. This way we would've
6099 discovered that from one visit to the other i_5 changed from
6100 range [8, 8] to VR_VARYING.
6102 However, fixing this apparent limitation may not be worth the
6103 additional checking. Testing on several code bases (GCC, DLV,
6104 MICO, TRAMP3D and SPEC2000) showed that doing this results in
6105 4 more predicates folded in SPEC. */
6108 val = vrp_evaluate_conditional_warnv_with_ops (gimple_cond_code (stmt),
6109 gimple_cond_lhs (stmt),
6110 gimple_cond_rhs (stmt),
6115 *taken_edge_p = find_taken_edge (gimple_bb (stmt), val);
6118 if (dump_file && (dump_flags & TDF_DETAILS))
6120 "\nIgnoring predicate evaluation because "
6121 "it assumes that signed overflow is undefined");
6126 if (dump_file && (dump_flags & TDF_DETAILS))
6128 fprintf (dump_file, "\nPredicate evaluates to: ");
6129 if (val == NULL_TREE)
6130 fprintf (dump_file, "DON'T KNOW\n");
6132 print_generic_stmt (dump_file, val, 0);
6135 return (*taken_edge_p) ? SSA_PROP_INTERESTING : SSA_PROP_VARYING;
6138 /* Searches the case label vector VEC for the index *IDX of the CASE_LABEL
6139 that includes the value VAL. The search is restricted to the range
6140 [START_IDX, n - 1] where n is the size of VEC.
6142 If there is a CASE_LABEL for VAL, its index is placed in IDX and true is
6145 If there is no CASE_LABEL for VAL and there is one that is larger than VAL,
6146 it is placed in IDX and false is returned.
6148 If VAL is larger than any CASE_LABEL, n is placed on IDX and false is
6152 find_case_label_index (gimple stmt, size_t start_idx, tree val, size_t *idx)
6154 size_t n = gimple_switch_num_labels (stmt);
6157 /* Find case label for minimum of the value range or the next one.
6158 At each iteration we are searching in [low, high - 1]. */
6160 for (low = start_idx, high = n; high != low; )
6164 /* Note that i != high, so we never ask for n. */
6165 size_t i = (high + low) / 2;
6166 t = gimple_switch_label (stmt, i);
6168 /* Cache the result of comparing CASE_LOW and val. */
6169 cmp = tree_int_cst_compare (CASE_LOW (t), val);
6173 /* Ranges cannot be empty. */
6182 if (CASE_HIGH (t) != NULL
6183 && tree_int_cst_compare (CASE_HIGH (t), val) >= 0)
6195 /* Searches the case label vector VEC for the range of CASE_LABELs that is used
6196 for values between MIN and MAX. The first index is placed in MIN_IDX. The
6197 last index is placed in MAX_IDX. If the range of CASE_LABELs is empty
6198 then MAX_IDX < MIN_IDX.
6199 Returns true if the default label is not needed. */
6202 find_case_label_range (gimple stmt, tree min, tree max, size_t *min_idx,
6206 bool min_take_default = !find_case_label_index (stmt, 1, min, &i);
6207 bool max_take_default = !find_case_label_index (stmt, i, max, &j);
6211 && max_take_default)
6213 /* Only the default case label reached.
6214 Return an empty range. */
6221 bool take_default = min_take_default || max_take_default;
6225 if (max_take_default)
6228 /* If the case label range is continuous, we do not need
6229 the default case label. Verify that. */
6230 high = CASE_LOW (gimple_switch_label (stmt, i));
6231 if (CASE_HIGH (gimple_switch_label (stmt, i)))
6232 high = CASE_HIGH (gimple_switch_label (stmt, i));
6233 for (k = i + 1; k <= j; ++k)
6235 low = CASE_LOW (gimple_switch_label (stmt, k));
6236 if (!integer_onep (int_const_binop (MINUS_EXPR, low, high, 0)))
6238 take_default = true;
6242 if (CASE_HIGH (gimple_switch_label (stmt, k)))
6243 high = CASE_HIGH (gimple_switch_label (stmt, k));
6248 return !take_default;
6252 /* Visit switch statement STMT. If we can determine which edge
6253 will be taken out of STMT's basic block, record it in
6254 *TAKEN_EDGE_P and return SSA_PROP_INTERESTING. Otherwise, return
6255 SSA_PROP_VARYING. */
6257 static enum ssa_prop_result
6258 vrp_visit_switch_stmt (gimple stmt, edge *taken_edge_p)
6262 size_t i = 0, j = 0;
6265 *taken_edge_p = NULL;
6266 op = gimple_switch_index (stmt);
6267 if (TREE_CODE (op) != SSA_NAME)
6268 return SSA_PROP_VARYING;
6270 vr = get_value_range (op);
6271 if (dump_file && (dump_flags & TDF_DETAILS))
6273 fprintf (dump_file, "\nVisiting switch expression with operand ");
6274 print_generic_expr (dump_file, op, 0);
6275 fprintf (dump_file, " with known range ");
6276 dump_value_range (dump_file, vr);
6277 fprintf (dump_file, "\n");
6280 if (vr->type != VR_RANGE
6281 || symbolic_range_p (vr))
6282 return SSA_PROP_VARYING;
6284 /* Find the single edge that is taken from the switch expression. */
6285 take_default = !find_case_label_range (stmt, vr->min, vr->max, &i, &j);
6287 /* Check if the range spans no CASE_LABEL. If so, we only reach the default
6291 gcc_assert (take_default);
6292 val = gimple_switch_default_label (stmt);
6296 /* Check if labels with index i to j and maybe the default label
6297 are all reaching the same label. */
6299 val = gimple_switch_label (stmt, i);
6301 && CASE_LABEL (gimple_switch_default_label (stmt))
6302 != CASE_LABEL (val))
6304 if (dump_file && (dump_flags & TDF_DETAILS))
6305 fprintf (dump_file, " not a single destination for this "
6307 return SSA_PROP_VARYING;
6309 for (++i; i <= j; ++i)
6311 if (CASE_LABEL (gimple_switch_label (stmt, i)) != CASE_LABEL (val))
6313 if (dump_file && (dump_flags & TDF_DETAILS))
6314 fprintf (dump_file, " not a single destination for this "
6316 return SSA_PROP_VARYING;
6321 *taken_edge_p = find_edge (gimple_bb (stmt),
6322 label_to_block (CASE_LABEL (val)));
6324 if (dump_file && (dump_flags & TDF_DETAILS))
6326 fprintf (dump_file, " will take edge to ");
6327 print_generic_stmt (dump_file, CASE_LABEL (val), 0);
6330 return SSA_PROP_INTERESTING;
6334 /* Evaluate statement STMT. If the statement produces a useful range,
6335 return SSA_PROP_INTERESTING and record the SSA name with the
6336 interesting range into *OUTPUT_P.
6338 If STMT is a conditional branch and we can determine its truth
6339 value, the taken edge is recorded in *TAKEN_EDGE_P.
6341 If STMT produces a varying value, return SSA_PROP_VARYING. */
6343 static enum ssa_prop_result
6344 vrp_visit_stmt (gimple stmt, edge *taken_edge_p, tree *output_p)
6349 if (dump_file && (dump_flags & TDF_DETAILS))
6351 fprintf (dump_file, "\nVisiting statement:\n");
6352 print_gimple_stmt (dump_file, stmt, 0, dump_flags);
6353 fprintf (dump_file, "\n");
6356 if (!stmt_interesting_for_vrp (stmt))
6357 gcc_assert (stmt_ends_bb_p (stmt));
6358 else if (is_gimple_assign (stmt) || is_gimple_call (stmt))
6360 /* In general, assignments with virtual operands are not useful
6361 for deriving ranges, with the obvious exception of calls to
6362 builtin functions. */
6364 if ((is_gimple_call (stmt)
6365 && gimple_call_fndecl (stmt) != NULL_TREE
6366 && DECL_IS_BUILTIN (gimple_call_fndecl (stmt)))
6367 || !gimple_vuse (stmt))
6368 return vrp_visit_assignment_or_call (stmt, output_p);
6370 else if (gimple_code (stmt) == GIMPLE_COND)
6371 return vrp_visit_cond_stmt (stmt, taken_edge_p);
6372 else if (gimple_code (stmt) == GIMPLE_SWITCH)
6373 return vrp_visit_switch_stmt (stmt, taken_edge_p);
6375 /* All other statements produce nothing of interest for VRP, so mark
6376 their outputs varying and prevent further simulation. */
6377 FOR_EACH_SSA_TREE_OPERAND (def, stmt, iter, SSA_OP_DEF)
6378 set_value_range_to_varying (get_value_range (def));
6380 return SSA_PROP_VARYING;
6384 /* Meet operation for value ranges. Given two value ranges VR0 and
6385 VR1, store in VR0 a range that contains both VR0 and VR1. This
6386 may not be the smallest possible such range. */
6389 vrp_meet (value_range_t *vr0, value_range_t *vr1)
6391 if (vr0->type == VR_UNDEFINED)
6393 copy_value_range (vr0, vr1);
6397 if (vr1->type == VR_UNDEFINED)
6399 /* Nothing to do. VR0 already has the resulting range. */
6403 if (vr0->type == VR_VARYING)
6405 /* Nothing to do. VR0 already has the resulting range. */
6409 if (vr1->type == VR_VARYING)
6411 set_value_range_to_varying (vr0);
6415 if (vr0->type == VR_RANGE && vr1->type == VR_RANGE)
6420 /* Compute the convex hull of the ranges. The lower limit of
6421 the new range is the minimum of the two ranges. If they
6422 cannot be compared, then give up. */
6423 cmp = compare_values (vr0->min, vr1->min);
6424 if (cmp == 0 || cmp == 1)
6431 /* Similarly, the upper limit of the new range is the maximum
6432 of the two ranges. If they cannot be compared, then
6434 cmp = compare_values (vr0->max, vr1->max);
6435 if (cmp == 0 || cmp == -1)
6442 /* Check for useless ranges. */
6443 if (INTEGRAL_TYPE_P (TREE_TYPE (min))
6444 && ((vrp_val_is_min (min) || is_overflow_infinity (min))
6445 && (vrp_val_is_max (max) || is_overflow_infinity (max))))
6448 /* The resulting set of equivalences is the intersection of
6450 if (vr0->equiv && vr1->equiv && vr0->equiv != vr1->equiv)
6451 bitmap_and_into (vr0->equiv, vr1->equiv);
6452 else if (vr0->equiv && !vr1->equiv)
6453 bitmap_clear (vr0->equiv);
6455 set_value_range (vr0, vr0->type, min, max, vr0->equiv);
6457 else if (vr0->type == VR_ANTI_RANGE && vr1->type == VR_ANTI_RANGE)
6459 /* Two anti-ranges meet only if their complements intersect.
6460 Only handle the case of identical ranges. */
6461 if (compare_values (vr0->min, vr1->min) == 0
6462 && compare_values (vr0->max, vr1->max) == 0
6463 && compare_values (vr0->min, vr0->max) == 0)
6465 /* The resulting set of equivalences is the intersection of
6467 if (vr0->equiv && vr1->equiv && vr0->equiv != vr1->equiv)
6468 bitmap_and_into (vr0->equiv, vr1->equiv);
6469 else if (vr0->equiv && !vr1->equiv)
6470 bitmap_clear (vr0->equiv);
6475 else if (vr0->type == VR_ANTI_RANGE || vr1->type == VR_ANTI_RANGE)
6477 /* For a numeric range [VAL1, VAL2] and an anti-range ~[VAL3, VAL4],
6478 only handle the case where the ranges have an empty intersection.
6479 The result of the meet operation is the anti-range. */
6480 if (!symbolic_range_p (vr0)
6481 && !symbolic_range_p (vr1)
6482 && !value_ranges_intersect_p (vr0, vr1))
6484 /* Copy most of VR1 into VR0. Don't copy VR1's equivalence
6485 set. We need to compute the intersection of the two
6486 equivalence sets. */
6487 if (vr1->type == VR_ANTI_RANGE)
6488 set_value_range (vr0, vr1->type, vr1->min, vr1->max, vr0->equiv);
6490 /* The resulting set of equivalences is the intersection of
6492 if (vr0->equiv && vr1->equiv && vr0->equiv != vr1->equiv)
6493 bitmap_and_into (vr0->equiv, vr1->equiv);
6494 else if (vr0->equiv && !vr1->equiv)
6495 bitmap_clear (vr0->equiv);
6506 /* Failed to find an efficient meet. Before giving up and setting
6507 the result to VARYING, see if we can at least derive a useful
6508 anti-range. FIXME, all this nonsense about distinguishing
6509 anti-ranges from ranges is necessary because of the odd
6510 semantics of range_includes_zero_p and friends. */
6511 if (!symbolic_range_p (vr0)
6512 && ((vr0->type == VR_RANGE && !range_includes_zero_p (vr0))
6513 || (vr0->type == VR_ANTI_RANGE && range_includes_zero_p (vr0)))
6514 && !symbolic_range_p (vr1)
6515 && ((vr1->type == VR_RANGE && !range_includes_zero_p (vr1))
6516 || (vr1->type == VR_ANTI_RANGE && range_includes_zero_p (vr1))))
6518 set_value_range_to_nonnull (vr0, TREE_TYPE (vr0->min));
6520 /* Since this meet operation did not result from the meeting of
6521 two equivalent names, VR0 cannot have any equivalences. */
6523 bitmap_clear (vr0->equiv);
6526 set_value_range_to_varying (vr0);
6530 /* Visit all arguments for PHI node PHI that flow through executable
6531 edges. If a valid value range can be derived from all the incoming
6532 value ranges, set a new range for the LHS of PHI. */
6534 static enum ssa_prop_result
6535 vrp_visit_phi_node (gimple phi)
6538 tree lhs = PHI_RESULT (phi);
6539 value_range_t *lhs_vr = get_value_range (lhs);
6540 value_range_t vr_result = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
6541 int edges, old_edges;
6544 if (dump_file && (dump_flags & TDF_DETAILS))
6546 fprintf (dump_file, "\nVisiting PHI node: ");
6547 print_gimple_stmt (dump_file, phi, 0, dump_flags);
6551 for (i = 0; i < gimple_phi_num_args (phi); i++)
6553 edge e = gimple_phi_arg_edge (phi, i);
6555 if (dump_file && (dump_flags & TDF_DETAILS))
6558 "\n Argument #%d (%d -> %d %sexecutable)\n",
6559 (int) i, e->src->index, e->dest->index,
6560 (e->flags & EDGE_EXECUTABLE) ? "" : "not ");
6563 if (e->flags & EDGE_EXECUTABLE)
6565 tree arg = PHI_ARG_DEF (phi, i);
6566 value_range_t vr_arg;
6570 if (TREE_CODE (arg) == SSA_NAME)
6572 vr_arg = *(get_value_range (arg));
6576 if (is_overflow_infinity (arg))
6578 arg = copy_node (arg);
6579 TREE_OVERFLOW (arg) = 0;
6582 vr_arg.type = VR_RANGE;
6585 vr_arg.equiv = NULL;
6588 if (dump_file && (dump_flags & TDF_DETAILS))
6590 fprintf (dump_file, "\t");
6591 print_generic_expr (dump_file, arg, dump_flags);
6592 fprintf (dump_file, "\n\tValue: ");
6593 dump_value_range (dump_file, &vr_arg);
6594 fprintf (dump_file, "\n");
6597 vrp_meet (&vr_result, &vr_arg);
6599 if (vr_result.type == VR_VARYING)
6604 if (vr_result.type == VR_VARYING)
6607 old_edges = vr_phi_edge_counts[SSA_NAME_VERSION (lhs)];
6608 vr_phi_edge_counts[SSA_NAME_VERSION (lhs)] = edges;
6610 /* To prevent infinite iterations in the algorithm, derive ranges
6611 when the new value is slightly bigger or smaller than the
6612 previous one. We don't do this if we have seen a new executable
6613 edge; this helps us avoid an overflow infinity for conditionals
6614 which are not in a loop. */
6616 && edges == old_edges)
6618 int cmp_min = compare_values (lhs_vr->min, vr_result.min);
6619 int cmp_max = compare_values (lhs_vr->max, vr_result.max);
6621 /* For non VR_RANGE or for pointers fall back to varying if
6622 the range changed. */
6623 if ((lhs_vr->type != VR_RANGE || vr_result.type != VR_RANGE
6624 || POINTER_TYPE_P (TREE_TYPE (lhs)))
6625 && (cmp_min != 0 || cmp_max != 0))
6628 /* If the new minimum is smaller or larger than the previous
6629 one, go all the way to -INF. In the first case, to avoid
6630 iterating millions of times to reach -INF, and in the
6631 other case to avoid infinite bouncing between different
6633 if (cmp_min > 0 || cmp_min < 0)
6635 if (!needs_overflow_infinity (TREE_TYPE (vr_result.min))
6636 || !vrp_var_may_overflow (lhs, phi))
6637 vr_result.min = TYPE_MIN_VALUE (TREE_TYPE (vr_result.min));
6638 else if (supports_overflow_infinity (TREE_TYPE (vr_result.min)))
6640 negative_overflow_infinity (TREE_TYPE (vr_result.min));
6643 /* Similarly, if the new maximum is smaller or larger than
6644 the previous one, go all the way to +INF. */
6645 if (cmp_max < 0 || cmp_max > 0)
6647 if (!needs_overflow_infinity (TREE_TYPE (vr_result.max))
6648 || !vrp_var_may_overflow (lhs, phi))
6649 vr_result.max = TYPE_MAX_VALUE (TREE_TYPE (vr_result.max));
6650 else if (supports_overflow_infinity (TREE_TYPE (vr_result.max)))
6652 positive_overflow_infinity (TREE_TYPE (vr_result.max));
6655 /* If we dropped either bound to +-INF then if this is a loop
6656 PHI node SCEV may known more about its value-range. */
6657 if ((cmp_min > 0 || cmp_min < 0
6658 || cmp_max < 0 || cmp_max > 0)
6660 && (l = loop_containing_stmt (phi))
6661 && l->header == gimple_bb (phi))
6662 adjust_range_with_scev (&vr_result, l, phi, lhs);
6664 /* If we will end up with a (-INF, +INF) range, set it to
6665 VARYING. Same if the previous max value was invalid for
6666 the type and we end up with vr_result.min > vr_result.max. */
6667 if ((vrp_val_is_max (vr_result.max)
6668 && vrp_val_is_min (vr_result.min))
6669 || compare_values (vr_result.min,
6674 /* If the new range is different than the previous value, keep
6676 if (update_value_range (lhs, &vr_result))
6678 if (dump_file && (dump_flags & TDF_DETAILS))
6680 fprintf (dump_file, "Found new range for ");
6681 print_generic_expr (dump_file, lhs, 0);
6682 fprintf (dump_file, ": ");
6683 dump_value_range (dump_file, &vr_result);
6684 fprintf (dump_file, "\n\n");
6687 return SSA_PROP_INTERESTING;
6690 /* Nothing changed, don't add outgoing edges. */
6691 return SSA_PROP_NOT_INTERESTING;
6693 /* No match found. Set the LHS to VARYING. */
6695 set_value_range_to_varying (lhs_vr);
6696 return SSA_PROP_VARYING;
6699 /* Simplify boolean operations if the source is known
6700 to be already a boolean. */
6702 simplify_truth_ops_using_ranges (gimple_stmt_iterator *gsi, gimple stmt)
6704 enum tree_code rhs_code = gimple_assign_rhs_code (stmt);
6709 bool need_conversion;
6711 op0 = gimple_assign_rhs1 (stmt);
6712 if (TYPE_PRECISION (TREE_TYPE (op0)) != 1)
6714 if (TREE_CODE (op0) != SSA_NAME)
6716 vr = get_value_range (op0);
6718 val = compare_range_with_value (GE_EXPR, vr, integer_zero_node, &sop);
6719 if (!val || !integer_onep (val))
6722 val = compare_range_with_value (LE_EXPR, vr, integer_one_node, &sop);
6723 if (!val || !integer_onep (val))
6727 if (rhs_code == TRUTH_NOT_EXPR)
6730 op1 = build_int_cst (TREE_TYPE (op0), 1);
6734 op1 = gimple_assign_rhs2 (stmt);
6736 /* Reduce number of cases to handle. */
6737 if (is_gimple_min_invariant (op1))
6739 /* Exclude anything that should have been already folded. */
6740 if (rhs_code != EQ_EXPR
6741 && rhs_code != NE_EXPR
6742 && rhs_code != TRUTH_XOR_EXPR)
6745 if (!integer_zerop (op1)
6746 && !integer_onep (op1)
6747 && !integer_all_onesp (op1))
6750 /* Limit the number of cases we have to consider. */
6751 if (rhs_code == EQ_EXPR)
6754 op1 = fold_unary (TRUTH_NOT_EXPR, TREE_TYPE (op1), op1);
6759 /* Punt on A == B as there is no BIT_XNOR_EXPR. */
6760 if (rhs_code == EQ_EXPR)
6763 if (TYPE_PRECISION (TREE_TYPE (op1)) != 1)
6765 vr = get_value_range (op1);
6766 val = compare_range_with_value (GE_EXPR, vr, integer_zero_node, &sop);
6767 if (!val || !integer_onep (val))
6770 val = compare_range_with_value (LE_EXPR, vr, integer_one_node, &sop);
6771 if (!val || !integer_onep (val))
6777 if (sop && issue_strict_overflow_warning (WARN_STRICT_OVERFLOW_MISC))
6779 location_t location;
6781 if (!gimple_has_location (stmt))
6782 location = input_location;
6784 location = gimple_location (stmt);
6786 if (rhs_code == TRUTH_AND_EXPR || rhs_code == TRUTH_OR_EXPR)
6787 warning_at (location, OPT_Wstrict_overflow,
6788 _("assuming signed overflow does not occur when "
6789 "simplifying && or || to & or |"));
6791 warning_at (location, OPT_Wstrict_overflow,
6792 _("assuming signed overflow does not occur when "
6793 "simplifying ==, != or ! to identity or ^"));
6797 !useless_type_conversion_p (TREE_TYPE (gimple_assign_lhs (stmt)),
6800 /* Make sure to not sign-extend -1 as a boolean value. */
6802 && !TYPE_UNSIGNED (TREE_TYPE (op0))
6803 && TYPE_PRECISION (TREE_TYPE (op0)) == 1)
6808 case TRUTH_AND_EXPR:
6809 rhs_code = BIT_AND_EXPR;
6812 rhs_code = BIT_IOR_EXPR;
6814 case TRUTH_XOR_EXPR:
6816 if (integer_zerop (op1))
6818 gimple_assign_set_rhs_with_ops (gsi,
6819 need_conversion ? NOP_EXPR : SSA_NAME,
6821 update_stmt (gsi_stmt (*gsi));
6825 rhs_code = BIT_XOR_EXPR;
6831 if (need_conversion)
6834 gimple_assign_set_rhs_with_ops (gsi, rhs_code, op0, op1);
6835 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 (NULL_TREE, 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, 0);
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 STMT using ranges if possible. */
7297 simplify_stmt_using_ranges (gimple_stmt_iterator *gsi)
7299 gimple stmt = gsi_stmt (*gsi);
7300 if (is_gimple_assign (stmt))
7302 enum tree_code rhs_code = gimple_assign_rhs_code (stmt);
7308 case TRUTH_NOT_EXPR:
7309 case TRUTH_AND_EXPR:
7311 case TRUTH_XOR_EXPR:
7312 /* Transform EQ_EXPR, NE_EXPR, TRUTH_NOT_EXPR into BIT_XOR_EXPR
7313 or identity if the RHS is zero or one, and the LHS are known
7314 to be boolean values. Transform all TRUTH_*_EXPR into
7315 BIT_*_EXPR if both arguments are known to be boolean values. */
7316 if (INTEGRAL_TYPE_P (TREE_TYPE (gimple_assign_rhs1 (stmt))))
7317 return simplify_truth_ops_using_ranges (gsi, stmt);
7320 /* Transform TRUNC_DIV_EXPR and TRUNC_MOD_EXPR into RSHIFT_EXPR
7321 and BIT_AND_EXPR respectively if the first operand is greater
7322 than zero and the second operand is an exact power of two. */
7323 case TRUNC_DIV_EXPR:
7324 case TRUNC_MOD_EXPR:
7325 if (INTEGRAL_TYPE_P (TREE_TYPE (gimple_assign_rhs1 (stmt)))
7326 && integer_pow2p (gimple_assign_rhs2 (stmt)))
7327 return simplify_div_or_mod_using_ranges (stmt);
7330 /* Transform ABS (X) into X or -X as appropriate. */
7332 if (TREE_CODE (gimple_assign_rhs1 (stmt)) == SSA_NAME
7333 && INTEGRAL_TYPE_P (TREE_TYPE (gimple_assign_rhs1 (stmt))))
7334 return simplify_abs_using_ranges (stmt);
7339 /* Optimize away BIT_AND_EXPR and BIT_IOR_EXPR
7340 if all the bits being cleared are already cleared or
7341 all the bits being set are already set. */
7342 if (INTEGRAL_TYPE_P (TREE_TYPE (gimple_assign_rhs1 (stmt))))
7343 return simplify_bit_ops_using_ranges (gsi, stmt);
7350 else if (gimple_code (stmt) == GIMPLE_COND)
7351 return simplify_cond_using_ranges (stmt);
7352 else if (gimple_code (stmt) == GIMPLE_SWITCH)
7353 return simplify_switch_using_ranges (stmt);
7358 /* If the statement pointed by SI has a predicate whose value can be
7359 computed using the value range information computed by VRP, compute
7360 its value and return true. Otherwise, return false. */
7363 fold_predicate_in (gimple_stmt_iterator *si)
7365 bool assignment_p = false;
7367 gimple stmt = gsi_stmt (*si);
7369 if (is_gimple_assign (stmt)
7370 && TREE_CODE_CLASS (gimple_assign_rhs_code (stmt)) == tcc_comparison)
7372 assignment_p = true;
7373 val = vrp_evaluate_conditional (gimple_assign_rhs_code (stmt),
7374 gimple_assign_rhs1 (stmt),
7375 gimple_assign_rhs2 (stmt),
7378 else if (gimple_code (stmt) == GIMPLE_COND)
7379 val = vrp_evaluate_conditional (gimple_cond_code (stmt),
7380 gimple_cond_lhs (stmt),
7381 gimple_cond_rhs (stmt),
7389 val = fold_convert (gimple_expr_type (stmt), val);
7393 fprintf (dump_file, "Folding predicate ");
7394 print_gimple_expr (dump_file, stmt, 0, 0);
7395 fprintf (dump_file, " to ");
7396 print_generic_expr (dump_file, val, 0);
7397 fprintf (dump_file, "\n");
7400 if (is_gimple_assign (stmt))
7401 gimple_assign_set_rhs_from_tree (si, val);
7404 gcc_assert (gimple_code (stmt) == GIMPLE_COND);
7405 if (integer_zerop (val))
7406 gimple_cond_make_false (stmt);
7407 else if (integer_onep (val))
7408 gimple_cond_make_true (stmt);
7419 /* Callback for substitute_and_fold folding the stmt at *SI. */
7422 vrp_fold_stmt (gimple_stmt_iterator *si)
7424 if (fold_predicate_in (si))
7427 return simplify_stmt_using_ranges (si);
7430 /* Stack of dest,src equivalency pairs that need to be restored after
7431 each attempt to thread a block's incoming edge to an outgoing edge.
7433 A NULL entry is used to mark the end of pairs which need to be
7435 static VEC(tree,heap) *stack;
7437 /* A trivial wrapper so that we can present the generic jump threading
7438 code with a simple API for simplifying statements. STMT is the
7439 statement we want to simplify, WITHIN_STMT provides the location
7440 for any overflow warnings. */
7443 simplify_stmt_for_jump_threading (gimple stmt, gimple within_stmt)
7445 /* We only use VRP information to simplify conditionals. This is
7446 overly conservative, but it's unclear if doing more would be
7447 worth the compile time cost. */
7448 if (gimple_code (stmt) != GIMPLE_COND)
7451 return vrp_evaluate_conditional (gimple_cond_code (stmt),
7452 gimple_cond_lhs (stmt),
7453 gimple_cond_rhs (stmt), within_stmt);
7456 /* Blocks which have more than one predecessor and more than
7457 one successor present jump threading opportunities, i.e.,
7458 when the block is reached from a specific predecessor, we
7459 may be able to determine which of the outgoing edges will
7460 be traversed. When this optimization applies, we are able
7461 to avoid conditionals at runtime and we may expose secondary
7462 optimization opportunities.
7464 This routine is effectively a driver for the generic jump
7465 threading code. It basically just presents the generic code
7466 with edges that may be suitable for jump threading.
7468 Unlike DOM, we do not iterate VRP if jump threading was successful.
7469 While iterating may expose new opportunities for VRP, it is expected
7470 those opportunities would be very limited and the compile time cost
7471 to expose those opportunities would be significant.
7473 As jump threading opportunities are discovered, they are registered
7474 for later realization. */
7477 identify_jump_threads (void)
7484 /* Ugh. When substituting values earlier in this pass we can
7485 wipe the dominance information. So rebuild the dominator
7486 information as we need it within the jump threading code. */
7487 calculate_dominance_info (CDI_DOMINATORS);
7489 /* We do not allow VRP information to be used for jump threading
7490 across a back edge in the CFG. Otherwise it becomes too
7491 difficult to avoid eliminating loop exit tests. Of course
7492 EDGE_DFS_BACK is not accurate at this time so we have to
7494 mark_dfs_back_edges ();
7496 /* Do not thread across edges we are about to remove. Just marking
7497 them as EDGE_DFS_BACK will do. */
7498 FOR_EACH_VEC_ELT (edge, to_remove_edges, i, e)
7499 e->flags |= EDGE_DFS_BACK;
7501 /* Allocate our unwinder stack to unwind any temporary equivalences
7502 that might be recorded. */
7503 stack = VEC_alloc (tree, heap, 20);
7505 /* To avoid lots of silly node creation, we create a single
7506 conditional and just modify it in-place when attempting to
7508 dummy = gimple_build_cond (EQ_EXPR,
7509 integer_zero_node, integer_zero_node,
7512 /* Walk through all the blocks finding those which present a
7513 potential jump threading opportunity. We could set this up
7514 as a dominator walker and record data during the walk, but
7515 I doubt it's worth the effort for the classes of jump
7516 threading opportunities we are trying to identify at this
7517 point in compilation. */
7522 /* If the generic jump threading code does not find this block
7523 interesting, then there is nothing to do. */
7524 if (! potentially_threadable_block (bb))
7527 /* We only care about blocks ending in a COND_EXPR. While there
7528 may be some value in handling SWITCH_EXPR here, I doubt it's
7529 terribly important. */
7530 last = gsi_stmt (gsi_last_bb (bb));
7531 if (gimple_code (last) != GIMPLE_COND)
7534 /* We're basically looking for any kind of conditional with
7535 integral type arguments. */
7536 if (TREE_CODE (gimple_cond_lhs (last)) == SSA_NAME
7537 && INTEGRAL_TYPE_P (TREE_TYPE (gimple_cond_lhs (last)))
7538 && (TREE_CODE (gimple_cond_rhs (last)) == SSA_NAME
7539 || is_gimple_min_invariant (gimple_cond_rhs (last)))
7540 && INTEGRAL_TYPE_P (TREE_TYPE (gimple_cond_rhs (last))))
7544 /* We've got a block with multiple predecessors and multiple
7545 successors which also ends in a suitable conditional. For
7546 each predecessor, see if we can thread it to a specific
7548 FOR_EACH_EDGE (e, ei, bb->preds)
7550 /* Do not thread across back edges or abnormal edges
7552 if (e->flags & (EDGE_DFS_BACK | EDGE_COMPLEX))
7555 thread_across_edge (dummy, e, true, &stack,
7556 simplify_stmt_for_jump_threading);
7561 /* We do not actually update the CFG or SSA graphs at this point as
7562 ASSERT_EXPRs are still in the IL and cfg cleanup code does not yet
7563 handle ASSERT_EXPRs gracefully. */
7566 /* We identified all the jump threading opportunities earlier, but could
7567 not transform the CFG at that time. This routine transforms the
7568 CFG and arranges for the dominator tree to be rebuilt if necessary.
7570 Note the SSA graph update will occur during the normal TODO
7571 processing by the pass manager. */
7573 finalize_jump_threads (void)
7575 thread_through_all_blocks (false);
7576 VEC_free (tree, heap, stack);
7580 /* Traverse all the blocks folding conditionals with known ranges. */
7586 unsigned num = num_ssa_names;
7590 fprintf (dump_file, "\nValue ranges after VRP:\n\n");
7591 dump_all_value_ranges (dump_file);
7592 fprintf (dump_file, "\n");
7595 substitute_and_fold (op_with_constant_singleton_value_range,
7596 vrp_fold_stmt, false);
7598 if (warn_array_bounds)
7599 check_all_array_refs ();
7601 /* We must identify jump threading opportunities before we release
7602 the datastructures built by VRP. */
7603 identify_jump_threads ();
7605 /* Free allocated memory. */
7606 for (i = 0; i < num; i++)
7609 BITMAP_FREE (vr_value[i]->equiv);
7614 free (vr_phi_edge_counts);
7616 /* So that we can distinguish between VRP data being available
7617 and not available. */
7619 vr_phi_edge_counts = NULL;
7623 /* Main entry point to VRP (Value Range Propagation). This pass is
7624 loosely based on J. R. C. Patterson, ``Accurate Static Branch
7625 Prediction by Value Range Propagation,'' in SIGPLAN Conference on
7626 Programming Language Design and Implementation, pp. 67-78, 1995.
7627 Also available at http://citeseer.ist.psu.edu/patterson95accurate.html
7629 This is essentially an SSA-CCP pass modified to deal with ranges
7630 instead of constants.
7632 While propagating ranges, we may find that two or more SSA name
7633 have equivalent, though distinct ranges. For instance,
7636 2 p_4 = ASSERT_EXPR <p_3, p_3 != 0>
7638 4 p_5 = ASSERT_EXPR <p_4, p_4 == q_2>;
7642 In the code above, pointer p_5 has range [q_2, q_2], but from the
7643 code we can also determine that p_5 cannot be NULL and, if q_2 had
7644 a non-varying range, p_5's range should also be compatible with it.
7646 These equivalences are created by two expressions: ASSERT_EXPR and
7647 copy operations. Since p_5 is an assertion on p_4, and p_4 was the
7648 result of another assertion, then we can use the fact that p_5 and
7649 p_4 are equivalent when evaluating p_5's range.
7651 Together with value ranges, we also propagate these equivalences
7652 between names so that we can take advantage of information from
7653 multiple ranges when doing final replacement. Note that this
7654 equivalency relation is transitive but not symmetric.
7656 In the example above, p_5 is equivalent to p_4, q_2 and p_3, but we
7657 cannot assert that q_2 is equivalent to p_5 because q_2 may be used
7658 in contexts where that assertion does not hold (e.g., in line 6).
7660 TODO, the main difference between this pass and Patterson's is that
7661 we do not propagate edge probabilities. We only compute whether
7662 edges can be taken or not. That is, instead of having a spectrum
7663 of jump probabilities between 0 and 1, we only deal with 0, 1 and
7664 DON'T KNOW. In the future, it may be worthwhile to propagate
7665 probabilities to aid branch prediction. */
7674 loop_optimizer_init (LOOPS_NORMAL | LOOPS_HAVE_RECORDED_EXITS);
7675 rewrite_into_loop_closed_ssa (NULL, TODO_update_ssa);
7678 /* Estimate number of iterations - but do not use undefined behavior
7679 for this. We can't do this lazily as other functions may compute
7680 this using undefined behavior. */
7681 free_numbers_of_iterations_estimates ();
7682 estimate_numbers_of_iterations (false);
7684 insert_range_assertions ();
7686 to_remove_edges = VEC_alloc (edge, heap, 10);
7687 to_update_switch_stmts = VEC_alloc (switch_update, heap, 5);
7688 threadedge_initialize_values ();
7691 ssa_propagate (vrp_visit_stmt, vrp_visit_phi_node);
7694 /* ASSERT_EXPRs must be removed before finalizing jump threads
7695 as finalizing jump threads calls the CFG cleanup code which
7696 does not properly handle ASSERT_EXPRs. */
7697 remove_range_assertions ();
7699 /* If we exposed any new variables, go ahead and put them into
7700 SSA form now, before we handle jump threading. This simplifies
7701 interactions between rewriting of _DECL nodes into SSA form
7702 and rewriting SSA_NAME nodes into SSA form after block
7703 duplication and CFG manipulation. */
7704 update_ssa (TODO_update_ssa);
7706 finalize_jump_threads ();
7708 /* Remove dead edges from SWITCH_EXPR optimization. This leaves the
7709 CFG in a broken state and requires a cfg_cleanup run. */
7710 FOR_EACH_VEC_ELT (edge, to_remove_edges, i, e)
7712 /* Update SWITCH_EXPR case label vector. */
7713 FOR_EACH_VEC_ELT (switch_update, to_update_switch_stmts, i, su)
7716 size_t n = TREE_VEC_LENGTH (su->vec);
7718 gimple_switch_set_num_labels (su->stmt, n);
7719 for (j = 0; j < n; j++)
7720 gimple_switch_set_label (su->stmt, j, TREE_VEC_ELT (su->vec, j));
7721 /* As we may have replaced the default label with a regular one
7722 make sure to make it a real default label again. This ensures
7723 optimal expansion. */
7724 label = gimple_switch_default_label (su->stmt);
7725 CASE_LOW (label) = NULL_TREE;
7726 CASE_HIGH (label) = NULL_TREE;
7729 if (VEC_length (edge, to_remove_edges) > 0)
7730 free_dominance_info (CDI_DOMINATORS);
7732 VEC_free (edge, heap, to_remove_edges);
7733 VEC_free (switch_update, heap, to_update_switch_stmts);
7734 threadedge_finalize_values ();
7737 loop_optimizer_finalize ();
7744 return flag_tree_vrp != 0;
7747 struct gimple_opt_pass pass_vrp =
7752 gate_vrp, /* gate */
7753 execute_vrp, /* execute */
7756 0, /* static_pass_number */
7757 TV_TREE_VRP, /* tv_id */
7758 PROP_ssa, /* properties_required */
7759 0, /* properties_provided */
7760 0, /* properties_destroyed */
7761 0, /* todo_flags_start */
7766 | TODO_update_ssa /* todo_flags_finish */