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 op0 is VR_RANGE, we can deduce a range
2460 even if op1 is VR_VARYING, VR_ANTI_RANGE, symbolic or can
2462 if ((code == TRUNC_DIV_EXPR
2463 || code == FLOOR_DIV_EXPR
2464 || code == CEIL_DIV_EXPR
2465 || code == EXACT_DIV_EXPR
2466 || code == ROUND_DIV_EXPR)
2467 && vr0.type == VR_RANGE
2468 && (vr1.type != VR_RANGE
2469 || symbolic_range_p (&vr1)
2470 || range_includes_zero_p (&vr1)))
2472 tree zero = build_int_cst (TREE_TYPE (vr0.min), 0);
2478 if (vrp_expr_computes_nonnegative (op1, &sop) && !sop)
2480 /* For unsigned division or when divisor is known
2481 to be non-negative, the range has to cover
2482 all numbers from 0 to max for positive max
2483 and all numbers from min to 0 for negative min. */
2484 cmp = compare_values (vr0.max, zero);
2487 else if (cmp == 0 || cmp == 1)
2491 cmp = compare_values (vr0.min, zero);
2494 else if (cmp == 0 || cmp == -1)
2501 /* Otherwise the range is -max .. max or min .. -min
2502 depending on which bound is bigger in absolute value,
2503 as the division can change the sign. */
2504 abs_extent_range (vr, vr0.min, vr0.max);
2507 if (type == VR_VARYING)
2509 set_value_range_to_varying (vr);
2514 /* Multiplications and divisions are a bit tricky to handle,
2515 depending on the mix of signs we have in the two ranges, we
2516 need to operate on different values to get the minimum and
2517 maximum values for the new range. One approach is to figure
2518 out all the variations of range combinations and do the
2521 However, this involves several calls to compare_values and it
2522 is pretty convoluted. It's simpler to do the 4 operations
2523 (MIN0 OP MIN1, MIN0 OP MAX1, MAX0 OP MIN1 and MAX0 OP MAX0 OP
2524 MAX1) and then figure the smallest and largest values to form
2528 gcc_assert ((vr0.type == VR_RANGE
2529 || (code == MULT_EXPR && vr0.type == VR_ANTI_RANGE))
2530 && vr0.type == vr1.type);
2532 /* Compute the 4 cross operations. */
2534 val[0] = vrp_int_const_binop (code, vr0.min, vr1.min);
2535 if (val[0] == NULL_TREE)
2538 if (vr1.max == vr1.min)
2542 val[1] = vrp_int_const_binop (code, vr0.min, vr1.max);
2543 if (val[1] == NULL_TREE)
2547 if (vr0.max == vr0.min)
2551 val[2] = vrp_int_const_binop (code, vr0.max, vr1.min);
2552 if (val[2] == NULL_TREE)
2556 if (vr0.min == vr0.max || vr1.min == vr1.max)
2560 val[3] = vrp_int_const_binop (code, vr0.max, vr1.max);
2561 if (val[3] == NULL_TREE)
2567 set_value_range_to_varying (vr);
2571 /* Set MIN to the minimum of VAL[i] and MAX to the maximum
2575 for (i = 1; i < 4; i++)
2577 if (!is_gimple_min_invariant (min)
2578 || (TREE_OVERFLOW (min) && !is_overflow_infinity (min))
2579 || !is_gimple_min_invariant (max)
2580 || (TREE_OVERFLOW (max) && !is_overflow_infinity (max)))
2585 if (!is_gimple_min_invariant (val[i])
2586 || (TREE_OVERFLOW (val[i])
2587 && !is_overflow_infinity (val[i])))
2589 /* If we found an overflowed value, set MIN and MAX
2590 to it so that we set the resulting range to
2596 if (compare_values (val[i], min) == -1)
2599 if (compare_values (val[i], max) == 1)
2605 else if (code == TRUNC_MOD_EXPR)
2608 if (vr1.type != VR_RANGE
2609 || symbolic_range_p (&vr1)
2610 || range_includes_zero_p (&vr1)
2611 || vrp_val_is_min (vr1.min))
2613 set_value_range_to_varying (vr);
2617 /* Compute MAX <|vr1.min|, |vr1.max|> - 1. */
2618 max = fold_unary_to_constant (ABS_EXPR, TREE_TYPE (vr1.min), vr1.min);
2619 if (tree_int_cst_lt (max, vr1.max))
2621 max = int_const_binop (MINUS_EXPR, max, integer_one_node, 0);
2622 /* If the dividend is non-negative the modulus will be
2623 non-negative as well. */
2624 if (TYPE_UNSIGNED (TREE_TYPE (max))
2625 || (vrp_expr_computes_nonnegative (op0, &sop) && !sop))
2626 min = build_int_cst (TREE_TYPE (max), 0);
2628 min = fold_unary_to_constant (NEGATE_EXPR, TREE_TYPE (max), max);
2630 else if (code == MINUS_EXPR)
2632 /* If we have a MINUS_EXPR with two VR_ANTI_RANGEs, drop to
2633 VR_VARYING. It would take more effort to compute a precise
2634 range for such a case. For example, if we have op0 == 1 and
2635 op1 == 1 with their ranges both being ~[0,0], we would have
2636 op0 - op1 == 0, so we cannot claim that the difference is in
2637 ~[0,0]. Note that we are guaranteed to have
2638 vr0.type == vr1.type at this point. */
2639 if (vr0.type == VR_ANTI_RANGE)
2641 set_value_range_to_varying (vr);
2645 /* For MINUS_EXPR, apply the operation to the opposite ends of
2647 min = vrp_int_const_binop (code, vr0.min, vr1.max);
2648 max = vrp_int_const_binop (code, vr0.max, vr1.min);
2650 else if (code == BIT_AND_EXPR || code == BIT_IOR_EXPR)
2652 bool vr0_int_cst_singleton_p, vr1_int_cst_singleton_p;
2653 bool int_cst_range0, int_cst_range1;
2654 double_int may_be_nonzero0, may_be_nonzero1;
2655 double_int must_be_nonzero0, must_be_nonzero1;
2657 vr0_int_cst_singleton_p = range_int_cst_singleton_p (&vr0);
2658 vr1_int_cst_singleton_p = range_int_cst_singleton_p (&vr1);
2659 int_cst_range0 = zero_nonzero_bits_from_vr (&vr0, &may_be_nonzero0,
2661 int_cst_range1 = zero_nonzero_bits_from_vr (&vr1, &may_be_nonzero1,
2665 if (vr0_int_cst_singleton_p && vr1_int_cst_singleton_p)
2666 min = max = int_const_binop (code, vr0.max, vr1.max, 0);
2667 else if (!int_cst_range0 && !int_cst_range1)
2669 set_value_range_to_varying (vr);
2672 else if (code == BIT_AND_EXPR)
2674 min = double_int_to_tree (expr_type,
2675 double_int_and (must_be_nonzero0,
2677 max = double_int_to_tree (expr_type,
2678 double_int_and (may_be_nonzero0,
2680 if (TREE_OVERFLOW (min) || tree_int_cst_sgn (min) < 0)
2682 if (TREE_OVERFLOW (max) || tree_int_cst_sgn (max) < 0)
2684 if (int_cst_range0 && tree_int_cst_sgn (vr0.min) >= 0)
2686 if (min == NULL_TREE)
2687 min = build_int_cst (expr_type, 0);
2688 if (max == NULL_TREE || tree_int_cst_lt (vr0.max, max))
2691 if (int_cst_range1 && tree_int_cst_sgn (vr1.min) >= 0)
2693 if (min == NULL_TREE)
2694 min = build_int_cst (expr_type, 0);
2695 if (max == NULL_TREE || tree_int_cst_lt (vr1.max, max))
2699 else if (!int_cst_range0
2701 || tree_int_cst_sgn (vr0.min) < 0
2702 || tree_int_cst_sgn (vr1.min) < 0)
2704 set_value_range_to_varying (vr);
2709 min = double_int_to_tree (expr_type,
2710 double_int_ior (must_be_nonzero0,
2712 max = double_int_to_tree (expr_type,
2713 double_int_ior (may_be_nonzero0,
2715 if (TREE_OVERFLOW (min) || tree_int_cst_sgn (min) < 0)
2718 min = vrp_int_const_binop (MAX_EXPR, min, vr0.min);
2719 if (TREE_OVERFLOW (max) || tree_int_cst_sgn (max) < 0)
2721 min = vrp_int_const_binop (MAX_EXPR, min, vr1.min);
2727 /* If either MIN or MAX overflowed, then set the resulting range to
2728 VARYING. But we do accept an overflow infinity
2730 if (min == NULL_TREE
2731 || !is_gimple_min_invariant (min)
2732 || (TREE_OVERFLOW (min) && !is_overflow_infinity (min))
2734 || !is_gimple_min_invariant (max)
2735 || (TREE_OVERFLOW (max) && !is_overflow_infinity (max)))
2737 set_value_range_to_varying (vr);
2743 2) [-INF, +-INF(OVF)]
2744 3) [+-INF(OVF), +INF]
2745 4) [+-INF(OVF), +-INF(OVF)]
2746 We learn nothing when we have INF and INF(OVF) on both sides.
2747 Note that we do accept [-INF, -INF] and [+INF, +INF] without
2749 if ((vrp_val_is_min (min) || is_overflow_infinity (min))
2750 && (vrp_val_is_max (max) || is_overflow_infinity (max)))
2752 set_value_range_to_varying (vr);
2756 cmp = compare_values (min, max);
2757 if (cmp == -2 || cmp == 1)
2759 /* If the new range has its limits swapped around (MIN > MAX),
2760 then the operation caused one of them to wrap around, mark
2761 the new range VARYING. */
2762 set_value_range_to_varying (vr);
2765 set_value_range (vr, type, min, max, NULL);
2769 /* Extract range information from a unary expression EXPR based on
2770 the range of its operand and the expression code. */
2773 extract_range_from_unary_expr (value_range_t *vr, enum tree_code code,
2774 tree type, tree op0)
2778 value_range_t vr0 = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
2780 /* Refuse to operate on certain unary expressions for which we
2781 cannot easily determine a resulting range. */
2782 if (code == FIX_TRUNC_EXPR
2783 || code == FLOAT_EXPR
2784 || code == BIT_NOT_EXPR
2785 || code == CONJ_EXPR)
2787 /* We can still do constant propagation here. */
2788 if ((op0 = op_with_constant_singleton_value_range (op0)) != NULL_TREE)
2790 tree tem = fold_unary (code, type, op0);
2792 && is_gimple_min_invariant (tem)
2793 && !is_overflow_infinity (tem))
2795 set_value_range (vr, VR_RANGE, tem, tem, NULL);
2799 set_value_range_to_varying (vr);
2803 /* Get value ranges for the operand. For constant operands, create
2804 a new value range with the operand to simplify processing. */
2805 if (TREE_CODE (op0) == SSA_NAME)
2806 vr0 = *(get_value_range (op0));
2807 else if (is_gimple_min_invariant (op0))
2808 set_value_range_to_value (&vr0, op0, NULL);
2810 set_value_range_to_varying (&vr0);
2812 /* If VR0 is UNDEFINED, so is the result. */
2813 if (vr0.type == VR_UNDEFINED)
2815 set_value_range_to_undefined (vr);
2819 /* Refuse to operate on symbolic ranges, or if neither operand is
2820 a pointer or integral type. */
2821 if ((!INTEGRAL_TYPE_P (TREE_TYPE (op0))
2822 && !POINTER_TYPE_P (TREE_TYPE (op0)))
2823 || (vr0.type != VR_VARYING
2824 && symbolic_range_p (&vr0)))
2826 set_value_range_to_varying (vr);
2830 /* If the expression involves pointers, we are only interested in
2831 determining if it evaluates to NULL [0, 0] or non-NULL (~[0, 0]). */
2832 if (POINTER_TYPE_P (type) || POINTER_TYPE_P (TREE_TYPE (op0)))
2837 if (range_is_nonnull (&vr0)
2838 || (tree_unary_nonzero_warnv_p (code, type, op0, &sop)
2840 set_value_range_to_nonnull (vr, type);
2841 else if (range_is_null (&vr0))
2842 set_value_range_to_null (vr, type);
2844 set_value_range_to_varying (vr);
2849 /* Handle unary expressions on integer ranges. */
2850 if (CONVERT_EXPR_CODE_P (code)
2851 && INTEGRAL_TYPE_P (type)
2852 && INTEGRAL_TYPE_P (TREE_TYPE (op0)))
2854 tree inner_type = TREE_TYPE (op0);
2855 tree outer_type = type;
2857 /* If VR0 is varying and we increase the type precision, assume
2858 a full range for the following transformation. */
2859 if (vr0.type == VR_VARYING
2860 && TYPE_PRECISION (inner_type) < TYPE_PRECISION (outer_type))
2862 vr0.type = VR_RANGE;
2863 vr0.min = TYPE_MIN_VALUE (inner_type);
2864 vr0.max = TYPE_MAX_VALUE (inner_type);
2867 /* If VR0 is a constant range or anti-range and the conversion is
2868 not truncating we can convert the min and max values and
2869 canonicalize the resulting range. Otherwise we can do the
2870 conversion if the size of the range is less than what the
2871 precision of the target type can represent and the range is
2872 not an anti-range. */
2873 if ((vr0.type == VR_RANGE
2874 || vr0.type == VR_ANTI_RANGE)
2875 && TREE_CODE (vr0.min) == INTEGER_CST
2876 && TREE_CODE (vr0.max) == INTEGER_CST
2877 && (!is_overflow_infinity (vr0.min)
2878 || (vr0.type == VR_RANGE
2879 && TYPE_PRECISION (outer_type) > TYPE_PRECISION (inner_type)
2880 && needs_overflow_infinity (outer_type)
2881 && supports_overflow_infinity (outer_type)))
2882 && (!is_overflow_infinity (vr0.max)
2883 || (vr0.type == VR_RANGE
2884 && TYPE_PRECISION (outer_type) > TYPE_PRECISION (inner_type)
2885 && needs_overflow_infinity (outer_type)
2886 && supports_overflow_infinity (outer_type)))
2887 && (TYPE_PRECISION (outer_type) >= TYPE_PRECISION (inner_type)
2888 || (vr0.type == VR_RANGE
2889 && integer_zerop (int_const_binop (RSHIFT_EXPR,
2890 int_const_binop (MINUS_EXPR, vr0.max, vr0.min, 0),
2891 size_int (TYPE_PRECISION (outer_type)), 0)))))
2893 tree new_min, new_max;
2894 new_min = force_fit_type_double (outer_type,
2895 tree_to_double_int (vr0.min),
2897 new_max = force_fit_type_double (outer_type,
2898 tree_to_double_int (vr0.max),
2900 if (is_overflow_infinity (vr0.min))
2901 new_min = negative_overflow_infinity (outer_type);
2902 if (is_overflow_infinity (vr0.max))
2903 new_max = positive_overflow_infinity (outer_type);
2904 set_and_canonicalize_value_range (vr, vr0.type,
2905 new_min, new_max, NULL);
2909 set_value_range_to_varying (vr);
2913 /* Conversion of a VR_VARYING value to a wider type can result
2914 in a usable range. So wait until after we've handled conversions
2915 before dropping the result to VR_VARYING if we had a source
2916 operand that is VR_VARYING. */
2917 if (vr0.type == VR_VARYING)
2919 set_value_range_to_varying (vr);
2923 /* Apply the operation to each end of the range and see what we end
2925 if (code == NEGATE_EXPR
2926 && !TYPE_UNSIGNED (type))
2928 /* NEGATE_EXPR flips the range around. We need to treat
2929 TYPE_MIN_VALUE specially. */
2930 if (is_positive_overflow_infinity (vr0.max))
2931 min = negative_overflow_infinity (type);
2932 else if (is_negative_overflow_infinity (vr0.max))
2933 min = positive_overflow_infinity (type);
2934 else if (!vrp_val_is_min (vr0.max))
2935 min = fold_unary_to_constant (code, type, vr0.max);
2936 else if (needs_overflow_infinity (type))
2938 if (supports_overflow_infinity (type)
2939 && !is_overflow_infinity (vr0.min)
2940 && !vrp_val_is_min (vr0.min))
2941 min = positive_overflow_infinity (type);
2944 set_value_range_to_varying (vr);
2949 min = TYPE_MIN_VALUE (type);
2951 if (is_positive_overflow_infinity (vr0.min))
2952 max = negative_overflow_infinity (type);
2953 else if (is_negative_overflow_infinity (vr0.min))
2954 max = positive_overflow_infinity (type);
2955 else if (!vrp_val_is_min (vr0.min))
2956 max = fold_unary_to_constant (code, type, vr0.min);
2957 else if (needs_overflow_infinity (type))
2959 if (supports_overflow_infinity (type))
2960 max = positive_overflow_infinity (type);
2963 set_value_range_to_varying (vr);
2968 max = TYPE_MIN_VALUE (type);
2970 else if (code == NEGATE_EXPR
2971 && TYPE_UNSIGNED (type))
2973 if (!range_includes_zero_p (&vr0))
2975 max = fold_unary_to_constant (code, type, vr0.min);
2976 min = fold_unary_to_constant (code, type, vr0.max);
2980 if (range_is_null (&vr0))
2981 set_value_range_to_null (vr, type);
2983 set_value_range_to_varying (vr);
2987 else if (code == ABS_EXPR
2988 && !TYPE_UNSIGNED (type))
2990 /* -TYPE_MIN_VALUE = TYPE_MIN_VALUE with flag_wrapv so we can't get a
2992 if (!TYPE_OVERFLOW_UNDEFINED (type)
2993 && ((vr0.type == VR_RANGE
2994 && vrp_val_is_min (vr0.min))
2995 || (vr0.type == VR_ANTI_RANGE
2996 && !vrp_val_is_min (vr0.min)
2997 && !range_includes_zero_p (&vr0))))
2999 set_value_range_to_varying (vr);
3003 /* ABS_EXPR may flip the range around, if the original range
3004 included negative values. */
3005 if (is_overflow_infinity (vr0.min))
3006 min = positive_overflow_infinity (type);
3007 else if (!vrp_val_is_min (vr0.min))
3008 min = fold_unary_to_constant (code, type, vr0.min);
3009 else if (!needs_overflow_infinity (type))
3010 min = TYPE_MAX_VALUE (type);
3011 else if (supports_overflow_infinity (type))
3012 min = positive_overflow_infinity (type);
3015 set_value_range_to_varying (vr);
3019 if (is_overflow_infinity (vr0.max))
3020 max = positive_overflow_infinity (type);
3021 else if (!vrp_val_is_min (vr0.max))
3022 max = fold_unary_to_constant (code, type, vr0.max);
3023 else if (!needs_overflow_infinity (type))
3024 max = TYPE_MAX_VALUE (type);
3025 else if (supports_overflow_infinity (type)
3026 /* We shouldn't generate [+INF, +INF] as set_value_range
3027 doesn't like this and ICEs. */
3028 && !is_positive_overflow_infinity (min))
3029 max = positive_overflow_infinity (type);
3032 set_value_range_to_varying (vr);
3036 cmp = compare_values (min, max);
3038 /* If a VR_ANTI_RANGEs contains zero, then we have
3039 ~[-INF, min(MIN, MAX)]. */
3040 if (vr0.type == VR_ANTI_RANGE)
3042 if (range_includes_zero_p (&vr0))
3044 /* Take the lower of the two values. */
3048 /* Create ~[-INF, min (abs(MIN), abs(MAX))]
3049 or ~[-INF + 1, min (abs(MIN), abs(MAX))] when
3050 flag_wrapv is set and the original anti-range doesn't include
3051 TYPE_MIN_VALUE, remember -TYPE_MIN_VALUE = TYPE_MIN_VALUE. */
3052 if (TYPE_OVERFLOW_WRAPS (type))
3054 tree type_min_value = TYPE_MIN_VALUE (type);
3056 min = (vr0.min != type_min_value
3057 ? int_const_binop (PLUS_EXPR, type_min_value,
3058 integer_one_node, 0)
3063 if (overflow_infinity_range_p (&vr0))
3064 min = negative_overflow_infinity (type);
3066 min = TYPE_MIN_VALUE (type);
3071 /* All else has failed, so create the range [0, INF], even for
3072 flag_wrapv since TYPE_MIN_VALUE is in the original
3074 vr0.type = VR_RANGE;
3075 min = build_int_cst (type, 0);
3076 if (needs_overflow_infinity (type))
3078 if (supports_overflow_infinity (type))
3079 max = positive_overflow_infinity (type);
3082 set_value_range_to_varying (vr);
3087 max = TYPE_MAX_VALUE (type);
3091 /* If the range contains zero then we know that the minimum value in the
3092 range will be zero. */
3093 else if (range_includes_zero_p (&vr0))
3097 min = build_int_cst (type, 0);
3101 /* If the range was reversed, swap MIN and MAX. */
3112 /* Otherwise, operate on each end of the range. */
3113 min = fold_unary_to_constant (code, type, vr0.min);
3114 max = fold_unary_to_constant (code, type, vr0.max);
3116 if (needs_overflow_infinity (type))
3118 gcc_assert (code != NEGATE_EXPR && code != ABS_EXPR);
3120 /* If both sides have overflowed, we don't know
3122 if ((is_overflow_infinity (vr0.min)
3123 || TREE_OVERFLOW (min))
3124 && (is_overflow_infinity (vr0.max)
3125 || TREE_OVERFLOW (max)))
3127 set_value_range_to_varying (vr);
3131 if (is_overflow_infinity (vr0.min))
3133 else if (TREE_OVERFLOW (min))
3135 if (supports_overflow_infinity (type))
3136 min = (tree_int_cst_sgn (min) >= 0
3137 ? positive_overflow_infinity (TREE_TYPE (min))
3138 : negative_overflow_infinity (TREE_TYPE (min)));
3141 set_value_range_to_varying (vr);
3146 if (is_overflow_infinity (vr0.max))
3148 else if (TREE_OVERFLOW (max))
3150 if (supports_overflow_infinity (type))
3151 max = (tree_int_cst_sgn (max) >= 0
3152 ? positive_overflow_infinity (TREE_TYPE (max))
3153 : negative_overflow_infinity (TREE_TYPE (max)));
3156 set_value_range_to_varying (vr);
3163 cmp = compare_values (min, max);
3164 if (cmp == -2 || cmp == 1)
3166 /* If the new range has its limits swapped around (MIN > MAX),
3167 then the operation caused one of them to wrap around, mark
3168 the new range VARYING. */
3169 set_value_range_to_varying (vr);
3172 set_value_range (vr, vr0.type, min, max, NULL);
3176 /* Extract range information from a conditional expression EXPR based on
3177 the ranges of each of its operands and the expression code. */
3180 extract_range_from_cond_expr (value_range_t *vr, tree expr)
3183 value_range_t vr0 = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
3184 value_range_t vr1 = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
3186 /* Get value ranges for each operand. For constant operands, create
3187 a new value range with the operand to simplify processing. */
3188 op0 = COND_EXPR_THEN (expr);
3189 if (TREE_CODE (op0) == SSA_NAME)
3190 vr0 = *(get_value_range (op0));
3191 else if (is_gimple_min_invariant (op0))
3192 set_value_range_to_value (&vr0, op0, NULL);
3194 set_value_range_to_varying (&vr0);
3196 op1 = COND_EXPR_ELSE (expr);
3197 if (TREE_CODE (op1) == SSA_NAME)
3198 vr1 = *(get_value_range (op1));
3199 else if (is_gimple_min_invariant (op1))
3200 set_value_range_to_value (&vr1, op1, NULL);
3202 set_value_range_to_varying (&vr1);
3204 /* The resulting value range is the union of the operand ranges */
3205 vrp_meet (&vr0, &vr1);
3206 copy_value_range (vr, &vr0);
3210 /* Extract range information from a comparison expression EXPR based
3211 on the range of its operand and the expression code. */
3214 extract_range_from_comparison (value_range_t *vr, enum tree_code code,
3215 tree type, tree op0, tree op1)
3220 val = vrp_evaluate_conditional_warnv_with_ops (code, op0, op1, false, &sop,
3223 /* A disadvantage of using a special infinity as an overflow
3224 representation is that we lose the ability to record overflow
3225 when we don't have an infinity. So we have to ignore a result
3226 which relies on overflow. */
3228 if (val && !is_overflow_infinity (val) && !sop)
3230 /* Since this expression was found on the RHS of an assignment,
3231 its type may be different from _Bool. Convert VAL to EXPR's
3233 val = fold_convert (type, val);
3234 if (is_gimple_min_invariant (val))
3235 set_value_range_to_value (vr, val, vr->equiv);
3237 set_value_range (vr, VR_RANGE, val, val, vr->equiv);
3240 /* The result of a comparison is always true or false. */
3241 set_value_range_to_truthvalue (vr, type);
3244 /* Try to derive a nonnegative or nonzero range out of STMT relying
3245 primarily on generic routines in fold in conjunction with range data.
3246 Store the result in *VR */
3249 extract_range_basic (value_range_t *vr, gimple stmt)
3252 tree type = gimple_expr_type (stmt);
3254 if (INTEGRAL_TYPE_P (type)
3255 && gimple_stmt_nonnegative_warnv_p (stmt, &sop))
3256 set_value_range_to_nonnegative (vr, type,
3257 sop || stmt_overflow_infinity (stmt));
3258 else if (vrp_stmt_computes_nonzero (stmt, &sop)
3260 set_value_range_to_nonnull (vr, type);
3262 set_value_range_to_varying (vr);
3266 /* Try to compute a useful range out of assignment STMT and store it
3270 extract_range_from_assignment (value_range_t *vr, gimple stmt)
3272 enum tree_code code = gimple_assign_rhs_code (stmt);
3274 if (code == ASSERT_EXPR)
3275 extract_range_from_assert (vr, gimple_assign_rhs1 (stmt));
3276 else if (code == SSA_NAME)
3277 extract_range_from_ssa_name (vr, gimple_assign_rhs1 (stmt));
3278 else if (TREE_CODE_CLASS (code) == tcc_binary
3279 || code == TRUTH_AND_EXPR
3280 || code == TRUTH_OR_EXPR
3281 || code == TRUTH_XOR_EXPR)
3282 extract_range_from_binary_expr (vr, gimple_assign_rhs_code (stmt),
3283 gimple_expr_type (stmt),
3284 gimple_assign_rhs1 (stmt),
3285 gimple_assign_rhs2 (stmt));
3286 else if (TREE_CODE_CLASS (code) == tcc_unary)
3287 extract_range_from_unary_expr (vr, gimple_assign_rhs_code (stmt),
3288 gimple_expr_type (stmt),
3289 gimple_assign_rhs1 (stmt));
3290 else if (code == COND_EXPR)
3291 extract_range_from_cond_expr (vr, gimple_assign_rhs1 (stmt));
3292 else if (TREE_CODE_CLASS (code) == tcc_comparison)
3293 extract_range_from_comparison (vr, gimple_assign_rhs_code (stmt),
3294 gimple_expr_type (stmt),
3295 gimple_assign_rhs1 (stmt),
3296 gimple_assign_rhs2 (stmt));
3297 else if (get_gimple_rhs_class (code) == GIMPLE_SINGLE_RHS
3298 && is_gimple_min_invariant (gimple_assign_rhs1 (stmt)))
3299 set_value_range_to_value (vr, gimple_assign_rhs1 (stmt), NULL);
3301 set_value_range_to_varying (vr);
3303 if (vr->type == VR_VARYING)
3304 extract_range_basic (vr, stmt);
3307 /* Given a range VR, a LOOP and a variable VAR, determine whether it
3308 would be profitable to adjust VR using scalar evolution information
3309 for VAR. If so, update VR with the new limits. */
3312 adjust_range_with_scev (value_range_t *vr, struct loop *loop,
3313 gimple stmt, tree var)
3315 tree init, step, chrec, tmin, tmax, min, max, type, tem;
3316 enum ev_direction dir;
3318 /* TODO. Don't adjust anti-ranges. An anti-range may provide
3319 better opportunities than a regular range, but I'm not sure. */
3320 if (vr->type == VR_ANTI_RANGE)
3323 chrec = instantiate_parameters (loop, analyze_scalar_evolution (loop, var));
3325 /* Like in PR19590, scev can return a constant function. */
3326 if (is_gimple_min_invariant (chrec))
3328 set_value_range_to_value (vr, chrec, vr->equiv);
3332 if (TREE_CODE (chrec) != POLYNOMIAL_CHREC)
3335 init = initial_condition_in_loop_num (chrec, loop->num);
3336 tem = op_with_constant_singleton_value_range (init);
3339 step = evolution_part_in_loop_num (chrec, loop->num);
3340 tem = op_with_constant_singleton_value_range (step);
3344 /* If STEP is symbolic, we can't know whether INIT will be the
3345 minimum or maximum value in the range. Also, unless INIT is
3346 a simple expression, compare_values and possibly other functions
3347 in tree-vrp won't be able to handle it. */
3348 if (step == NULL_TREE
3349 || !is_gimple_min_invariant (step)
3350 || !valid_value_p (init))
3353 dir = scev_direction (chrec);
3354 if (/* Do not adjust ranges if we do not know whether the iv increases
3355 or decreases, ... */
3356 dir == EV_DIR_UNKNOWN
3357 /* ... or if it may wrap. */
3358 || scev_probably_wraps_p (init, step, stmt, get_chrec_loop (chrec),
3362 /* We use TYPE_MIN_VALUE and TYPE_MAX_VALUE here instead of
3363 negative_overflow_infinity and positive_overflow_infinity,
3364 because we have concluded that the loop probably does not
3367 type = TREE_TYPE (var);
3368 if (POINTER_TYPE_P (type) || !TYPE_MIN_VALUE (type))
3369 tmin = lower_bound_in_type (type, type);
3371 tmin = TYPE_MIN_VALUE (type);
3372 if (POINTER_TYPE_P (type) || !TYPE_MAX_VALUE (type))
3373 tmax = upper_bound_in_type (type, type);
3375 tmax = TYPE_MAX_VALUE (type);
3377 /* Try to use estimated number of iterations for the loop to constrain the
3378 final value in the evolution.
3379 We are interested in the number of executions of the latch, while
3380 nb_iterations_upper_bound includes the last execution of the exit test. */
3381 if (TREE_CODE (step) == INTEGER_CST
3382 && loop->any_upper_bound
3383 && !double_int_zero_p (loop->nb_iterations_upper_bound)
3384 && is_gimple_val (init)
3385 && (TREE_CODE (init) != SSA_NAME
3386 || get_value_range (init)->type == VR_RANGE))
3388 value_range_t maxvr = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
3390 dtmp = double_int_mul (tree_to_double_int (step),
3391 double_int_sub (loop->nb_iterations_upper_bound,
3393 tem = double_int_to_tree (TREE_TYPE (init), dtmp);
3394 /* If the multiplication overflowed we can't do a meaningful
3396 if (double_int_equal_p (dtmp, tree_to_double_int (tem)))
3398 extract_range_from_binary_expr (&maxvr, PLUS_EXPR,
3399 TREE_TYPE (init), init, tem);
3400 /* Likewise if the addition did. */
3401 if (maxvr.type == VR_RANGE)
3409 if (vr->type == VR_VARYING || vr->type == VR_UNDEFINED)
3414 /* For VARYING or UNDEFINED ranges, just about anything we get
3415 from scalar evolutions should be better. */
3417 if (dir == EV_DIR_DECREASES)
3422 /* If we would create an invalid range, then just assume we
3423 know absolutely nothing. This may be over-conservative,
3424 but it's clearly safe, and should happen only in unreachable
3425 parts of code, or for invalid programs. */
3426 if (compare_values (min, max) == 1)
3429 set_value_range (vr, VR_RANGE, min, max, vr->equiv);
3431 else if (vr->type == VR_RANGE)
3436 if (dir == EV_DIR_DECREASES)
3438 /* INIT is the maximum value. If INIT is lower than VR->MAX
3439 but no smaller than VR->MIN, set VR->MAX to INIT. */
3440 if (compare_values (init, max) == -1)
3443 /* According to the loop information, the variable does not
3444 overflow. If we think it does, probably because of an
3445 overflow due to arithmetic on a different INF value,
3447 if (is_negative_overflow_infinity (min)
3448 || compare_values (min, tmin) == -1)
3454 /* If INIT is bigger than VR->MIN, set VR->MIN to INIT. */
3455 if (compare_values (init, min) == 1)
3458 if (is_positive_overflow_infinity (max)
3459 || compare_values (tmax, max) == -1)
3463 /* If we just created an invalid range with the minimum
3464 greater than the maximum, we fail conservatively.
3465 This should happen only in unreachable
3466 parts of code, or for invalid programs. */
3467 if (compare_values (min, max) == 1)
3470 set_value_range (vr, VR_RANGE, min, max, vr->equiv);
3474 /* Return true if VAR may overflow at STMT. This checks any available
3475 loop information to see if we can determine that VAR does not
3479 vrp_var_may_overflow (tree var, gimple stmt)
3482 tree chrec, init, step;
3484 if (current_loops == NULL)
3487 l = loop_containing_stmt (stmt);
3492 chrec = instantiate_parameters (l, analyze_scalar_evolution (l, var));
3493 if (TREE_CODE (chrec) != POLYNOMIAL_CHREC)
3496 init = initial_condition_in_loop_num (chrec, l->num);
3497 step = evolution_part_in_loop_num (chrec, l->num);
3499 if (step == NULL_TREE
3500 || !is_gimple_min_invariant (step)
3501 || !valid_value_p (init))
3504 /* If we get here, we know something useful about VAR based on the
3505 loop information. If it wraps, it may overflow. */
3507 if (scev_probably_wraps_p (init, step, stmt, get_chrec_loop (chrec),
3511 if (dump_file && (dump_flags & TDF_DETAILS) != 0)
3513 print_generic_expr (dump_file, var, 0);
3514 fprintf (dump_file, ": loop information indicates does not overflow\n");
3521 /* Given two numeric value ranges VR0, VR1 and a comparison code COMP:
3523 - Return BOOLEAN_TRUE_NODE if VR0 COMP VR1 always returns true for
3524 all the values in the ranges.
3526 - Return BOOLEAN_FALSE_NODE if the comparison always returns false.
3528 - Return NULL_TREE if it is not always possible to determine the
3529 value of the comparison.
3531 Also set *STRICT_OVERFLOW_P to indicate whether a range with an
3532 overflow infinity was used in the test. */
3536 compare_ranges (enum tree_code comp, value_range_t *vr0, value_range_t *vr1,
3537 bool *strict_overflow_p)
3539 /* VARYING or UNDEFINED ranges cannot be compared. */
3540 if (vr0->type == VR_VARYING
3541 || vr0->type == VR_UNDEFINED
3542 || vr1->type == VR_VARYING
3543 || vr1->type == VR_UNDEFINED)
3546 /* Anti-ranges need to be handled separately. */
3547 if (vr0->type == VR_ANTI_RANGE || vr1->type == VR_ANTI_RANGE)
3549 /* If both are anti-ranges, then we cannot compute any
3551 if (vr0->type == VR_ANTI_RANGE && vr1->type == VR_ANTI_RANGE)
3554 /* These comparisons are never statically computable. */
3561 /* Equality can be computed only between a range and an
3562 anti-range. ~[VAL1, VAL2] == [VAL1, VAL2] is always false. */
3563 if (vr0->type == VR_RANGE)
3565 /* To simplify processing, make VR0 the anti-range. */
3566 value_range_t *tmp = vr0;
3571 gcc_assert (comp == NE_EXPR || comp == EQ_EXPR);
3573 if (compare_values_warnv (vr0->min, vr1->min, strict_overflow_p) == 0
3574 && compare_values_warnv (vr0->max, vr1->max, strict_overflow_p) == 0)
3575 return (comp == NE_EXPR) ? boolean_true_node : boolean_false_node;
3580 if (!usable_range_p (vr0, strict_overflow_p)
3581 || !usable_range_p (vr1, strict_overflow_p))
3584 /* Simplify processing. If COMP is GT_EXPR or GE_EXPR, switch the
3585 operands around and change the comparison code. */
3586 if (comp == GT_EXPR || comp == GE_EXPR)
3589 comp = (comp == GT_EXPR) ? LT_EXPR : LE_EXPR;
3595 if (comp == EQ_EXPR)
3597 /* Equality may only be computed if both ranges represent
3598 exactly one value. */
3599 if (compare_values_warnv (vr0->min, vr0->max, strict_overflow_p) == 0
3600 && compare_values_warnv (vr1->min, vr1->max, strict_overflow_p) == 0)
3602 int cmp_min = compare_values_warnv (vr0->min, vr1->min,
3604 int cmp_max = compare_values_warnv (vr0->max, vr1->max,
3606 if (cmp_min == 0 && cmp_max == 0)
3607 return boolean_true_node;
3608 else if (cmp_min != -2 && cmp_max != -2)
3609 return boolean_false_node;
3611 /* If [V0_MIN, V1_MAX] < [V1_MIN, V1_MAX] then V0 != V1. */
3612 else if (compare_values_warnv (vr0->min, vr1->max,
3613 strict_overflow_p) == 1
3614 || compare_values_warnv (vr1->min, vr0->max,
3615 strict_overflow_p) == 1)
3616 return boolean_false_node;
3620 else if (comp == NE_EXPR)
3624 /* If VR0 is completely to the left or completely to the right
3625 of VR1, they are always different. Notice that we need to
3626 make sure that both comparisons yield similar results to
3627 avoid comparing values that cannot be compared at
3629 cmp1 = compare_values_warnv (vr0->max, vr1->min, strict_overflow_p);
3630 cmp2 = compare_values_warnv (vr0->min, vr1->max, strict_overflow_p);
3631 if ((cmp1 == -1 && cmp2 == -1) || (cmp1 == 1 && cmp2 == 1))
3632 return boolean_true_node;
3634 /* If VR0 and VR1 represent a single value and are identical,
3636 else if (compare_values_warnv (vr0->min, vr0->max,
3637 strict_overflow_p) == 0
3638 && compare_values_warnv (vr1->min, vr1->max,
3639 strict_overflow_p) == 0
3640 && compare_values_warnv (vr0->min, vr1->min,
3641 strict_overflow_p) == 0
3642 && compare_values_warnv (vr0->max, vr1->max,
3643 strict_overflow_p) == 0)
3644 return boolean_false_node;
3646 /* Otherwise, they may or may not be different. */
3650 else if (comp == LT_EXPR || comp == LE_EXPR)
3654 /* If VR0 is to the left of VR1, return true. */
3655 tst = compare_values_warnv (vr0->max, vr1->min, strict_overflow_p);
3656 if ((comp == LT_EXPR && tst == -1)
3657 || (comp == LE_EXPR && (tst == -1 || tst == 0)))
3659 if (overflow_infinity_range_p (vr0)
3660 || overflow_infinity_range_p (vr1))
3661 *strict_overflow_p = true;
3662 return boolean_true_node;
3665 /* If VR0 is to the right of VR1, return false. */
3666 tst = compare_values_warnv (vr0->min, vr1->max, strict_overflow_p);
3667 if ((comp == LT_EXPR && (tst == 0 || tst == 1))
3668 || (comp == LE_EXPR && tst == 1))
3670 if (overflow_infinity_range_p (vr0)
3671 || overflow_infinity_range_p (vr1))
3672 *strict_overflow_p = true;
3673 return boolean_false_node;
3676 /* Otherwise, we don't know. */
3684 /* Given a value range VR, a value VAL and a comparison code COMP, return
3685 BOOLEAN_TRUE_NODE if VR COMP VAL always returns true for all the
3686 values in VR. Return BOOLEAN_FALSE_NODE if the comparison
3687 always returns false. Return NULL_TREE if it is not always
3688 possible to determine the value of the comparison. Also set
3689 *STRICT_OVERFLOW_P to indicate whether a range with an overflow
3690 infinity was used in the test. */
3693 compare_range_with_value (enum tree_code comp, value_range_t *vr, tree val,
3694 bool *strict_overflow_p)
3696 if (vr->type == VR_VARYING || vr->type == VR_UNDEFINED)
3699 /* Anti-ranges need to be handled separately. */
3700 if (vr->type == VR_ANTI_RANGE)
3702 /* For anti-ranges, the only predicates that we can compute at
3703 compile time are equality and inequality. */
3710 /* ~[VAL_1, VAL_2] OP VAL is known if VAL_1 <= VAL <= VAL_2. */
3711 if (value_inside_range (val, vr) == 1)
3712 return (comp == NE_EXPR) ? boolean_true_node : boolean_false_node;
3717 if (!usable_range_p (vr, strict_overflow_p))
3720 if (comp == EQ_EXPR)
3722 /* EQ_EXPR may only be computed if VR represents exactly
3724 if (compare_values_warnv (vr->min, vr->max, strict_overflow_p) == 0)
3726 int cmp = compare_values_warnv (vr->min, val, strict_overflow_p);
3728 return boolean_true_node;
3729 else if (cmp == -1 || cmp == 1 || cmp == 2)
3730 return boolean_false_node;
3732 else if (compare_values_warnv (val, vr->min, strict_overflow_p) == -1
3733 || compare_values_warnv (vr->max, val, strict_overflow_p) == -1)
3734 return boolean_false_node;
3738 else if (comp == NE_EXPR)
3740 /* If VAL is not inside VR, then they are always different. */
3741 if (compare_values_warnv (vr->max, val, strict_overflow_p) == -1
3742 || compare_values_warnv (vr->min, val, strict_overflow_p) == 1)
3743 return boolean_true_node;
3745 /* If VR represents exactly one value equal to VAL, then return
3747 if (compare_values_warnv (vr->min, vr->max, strict_overflow_p) == 0
3748 && compare_values_warnv (vr->min, val, strict_overflow_p) == 0)
3749 return boolean_false_node;
3751 /* Otherwise, they may or may not be different. */
3754 else if (comp == LT_EXPR || comp == LE_EXPR)
3758 /* If VR is to the left of VAL, return true. */
3759 tst = compare_values_warnv (vr->max, val, strict_overflow_p);
3760 if ((comp == LT_EXPR && tst == -1)
3761 || (comp == LE_EXPR && (tst == -1 || tst == 0)))
3763 if (overflow_infinity_range_p (vr))
3764 *strict_overflow_p = true;
3765 return boolean_true_node;
3768 /* If VR is to the right of VAL, return false. */
3769 tst = compare_values_warnv (vr->min, val, strict_overflow_p);
3770 if ((comp == LT_EXPR && (tst == 0 || tst == 1))
3771 || (comp == LE_EXPR && tst == 1))
3773 if (overflow_infinity_range_p (vr))
3774 *strict_overflow_p = true;
3775 return boolean_false_node;
3778 /* Otherwise, we don't know. */
3781 else if (comp == GT_EXPR || comp == GE_EXPR)
3785 /* If VR is to the right of VAL, return true. */
3786 tst = compare_values_warnv (vr->min, val, strict_overflow_p);
3787 if ((comp == GT_EXPR && tst == 1)
3788 || (comp == GE_EXPR && (tst == 0 || tst == 1)))
3790 if (overflow_infinity_range_p (vr))
3791 *strict_overflow_p = true;
3792 return boolean_true_node;
3795 /* If VR is to the left of VAL, return false. */
3796 tst = compare_values_warnv (vr->max, val, strict_overflow_p);
3797 if ((comp == GT_EXPR && (tst == -1 || tst == 0))
3798 || (comp == GE_EXPR && tst == -1))
3800 if (overflow_infinity_range_p (vr))
3801 *strict_overflow_p = true;
3802 return boolean_false_node;
3805 /* Otherwise, we don't know. */
3813 /* Debugging dumps. */
3815 void dump_value_range (FILE *, value_range_t *);
3816 void debug_value_range (value_range_t *);
3817 void dump_all_value_ranges (FILE *);
3818 void debug_all_value_ranges (void);
3819 void dump_vr_equiv (FILE *, bitmap);
3820 void debug_vr_equiv (bitmap);
3823 /* Dump value range VR to FILE. */
3826 dump_value_range (FILE *file, value_range_t *vr)
3829 fprintf (file, "[]");
3830 else if (vr->type == VR_UNDEFINED)
3831 fprintf (file, "UNDEFINED");
3832 else if (vr->type == VR_RANGE || vr->type == VR_ANTI_RANGE)
3834 tree type = TREE_TYPE (vr->min);
3836 fprintf (file, "%s[", (vr->type == VR_ANTI_RANGE) ? "~" : "");
3838 if (is_negative_overflow_infinity (vr->min))
3839 fprintf (file, "-INF(OVF)");
3840 else if (INTEGRAL_TYPE_P (type)
3841 && !TYPE_UNSIGNED (type)
3842 && vrp_val_is_min (vr->min))
3843 fprintf (file, "-INF");
3845 print_generic_expr (file, vr->min, 0);
3847 fprintf (file, ", ");
3849 if (is_positive_overflow_infinity (vr->max))
3850 fprintf (file, "+INF(OVF)");
3851 else if (INTEGRAL_TYPE_P (type)
3852 && vrp_val_is_max (vr->max))
3853 fprintf (file, "+INF");
3855 print_generic_expr (file, vr->max, 0);
3857 fprintf (file, "]");
3864 fprintf (file, " EQUIVALENCES: { ");
3866 EXECUTE_IF_SET_IN_BITMAP (vr->equiv, 0, i, bi)
3868 print_generic_expr (file, ssa_name (i), 0);
3869 fprintf (file, " ");
3873 fprintf (file, "} (%u elements)", c);
3876 else if (vr->type == VR_VARYING)
3877 fprintf (file, "VARYING");
3879 fprintf (file, "INVALID RANGE");
3883 /* Dump value range VR to stderr. */
3886 debug_value_range (value_range_t *vr)
3888 dump_value_range (stderr, vr);
3889 fprintf (stderr, "\n");
3893 /* Dump value ranges of all SSA_NAMEs to FILE. */
3896 dump_all_value_ranges (FILE *file)
3900 for (i = 0; i < num_ssa_names; i++)
3904 print_generic_expr (file, ssa_name (i), 0);
3905 fprintf (file, ": ");
3906 dump_value_range (file, vr_value[i]);
3907 fprintf (file, "\n");
3911 fprintf (file, "\n");
3915 /* Dump all value ranges to stderr. */
3918 debug_all_value_ranges (void)
3920 dump_all_value_ranges (stderr);
3924 /* Given a COND_EXPR COND of the form 'V OP W', and an SSA name V,
3925 create a new SSA name N and return the assertion assignment
3926 'V = ASSERT_EXPR <V, V OP W>'. */
3929 build_assert_expr_for (tree cond, tree v)
3934 gcc_assert (TREE_CODE (v) == SSA_NAME);
3935 n = duplicate_ssa_name (v, NULL);
3937 if (COMPARISON_CLASS_P (cond))
3939 tree a = build2 (ASSERT_EXPR, TREE_TYPE (v), v, cond);
3940 assertion = gimple_build_assign (n, a);
3942 else if (TREE_CODE (cond) == TRUTH_NOT_EXPR)
3944 /* Given !V, build the assignment N = false. */
3945 tree op0 = TREE_OPERAND (cond, 0);
3946 gcc_assert (op0 == v);
3947 assertion = gimple_build_assign (n, boolean_false_node);
3949 else if (TREE_CODE (cond) == SSA_NAME)
3951 /* Given V, build the assignment N = true. */
3952 gcc_assert (v == cond);
3953 assertion = gimple_build_assign (n, boolean_true_node);
3958 SSA_NAME_DEF_STMT (n) = assertion;
3960 /* The new ASSERT_EXPR, creates a new SSA name that replaces the
3961 operand of the ASSERT_EXPR. Register the new name and the old one
3962 in the replacement table so that we can fix the SSA web after
3963 adding all the ASSERT_EXPRs. */
3964 register_new_name_mapping (n, v);
3970 /* Return false if EXPR is a predicate expression involving floating
3974 fp_predicate (gimple stmt)
3976 GIMPLE_CHECK (stmt, GIMPLE_COND);
3978 return FLOAT_TYPE_P (TREE_TYPE (gimple_cond_lhs (stmt)));
3982 /* If the range of values taken by OP can be inferred after STMT executes,
3983 return the comparison code (COMP_CODE_P) and value (VAL_P) that
3984 describes the inferred range. Return true if a range could be
3988 infer_value_range (gimple stmt, tree op, enum tree_code *comp_code_p, tree *val_p)
3991 *comp_code_p = ERROR_MARK;
3993 /* Do not attempt to infer anything in names that flow through
3995 if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (op))
3998 /* Similarly, don't infer anything from statements that may throw
4000 if (stmt_could_throw_p (stmt))
4003 /* If STMT is the last statement of a basic block with no
4004 successors, there is no point inferring anything about any of its
4005 operands. We would not be able to find a proper insertion point
4006 for the assertion, anyway. */
4007 if (stmt_ends_bb_p (stmt) && EDGE_COUNT (gimple_bb (stmt)->succs) == 0)
4010 /* We can only assume that a pointer dereference will yield
4011 non-NULL if -fdelete-null-pointer-checks is enabled. */
4012 if (flag_delete_null_pointer_checks
4013 && POINTER_TYPE_P (TREE_TYPE (op))
4014 && gimple_code (stmt) != GIMPLE_ASM)
4016 unsigned num_uses, num_loads, num_stores;
4018 count_uses_and_derefs (op, stmt, &num_uses, &num_loads, &num_stores);
4019 if (num_loads + num_stores > 0)
4021 *val_p = build_int_cst (TREE_TYPE (op), 0);
4022 *comp_code_p = NE_EXPR;
4031 void dump_asserts_for (FILE *, tree);
4032 void debug_asserts_for (tree);
4033 void dump_all_asserts (FILE *);
4034 void debug_all_asserts (void);
4036 /* Dump all the registered assertions for NAME to FILE. */
4039 dump_asserts_for (FILE *file, tree name)
4043 fprintf (file, "Assertions to be inserted for ");
4044 print_generic_expr (file, name, 0);
4045 fprintf (file, "\n");
4047 loc = asserts_for[SSA_NAME_VERSION (name)];
4050 fprintf (file, "\t");
4051 print_gimple_stmt (file, gsi_stmt (loc->si), 0, 0);
4052 fprintf (file, "\n\tBB #%d", loc->bb->index);
4055 fprintf (file, "\n\tEDGE %d->%d", loc->e->src->index,
4056 loc->e->dest->index);
4057 dump_edge_info (file, loc->e, 0);
4059 fprintf (file, "\n\tPREDICATE: ");
4060 print_generic_expr (file, name, 0);
4061 fprintf (file, " %s ", tree_code_name[(int)loc->comp_code]);
4062 print_generic_expr (file, loc->val, 0);
4063 fprintf (file, "\n\n");
4067 fprintf (file, "\n");
4071 /* Dump all the registered assertions for NAME to stderr. */
4074 debug_asserts_for (tree name)
4076 dump_asserts_for (stderr, name);
4080 /* Dump all the registered assertions for all the names to FILE. */
4083 dump_all_asserts (FILE *file)
4088 fprintf (file, "\nASSERT_EXPRs to be inserted\n\n");
4089 EXECUTE_IF_SET_IN_BITMAP (need_assert_for, 0, i, bi)
4090 dump_asserts_for (file, ssa_name (i));
4091 fprintf (file, "\n");
4095 /* Dump all the registered assertions for all the names to stderr. */
4098 debug_all_asserts (void)
4100 dump_all_asserts (stderr);
4104 /* If NAME doesn't have an ASSERT_EXPR registered for asserting
4105 'EXPR COMP_CODE VAL' at a location that dominates block BB or
4106 E->DEST, then register this location as a possible insertion point
4107 for ASSERT_EXPR <NAME, EXPR COMP_CODE VAL>.
4109 BB, E and SI provide the exact insertion point for the new
4110 ASSERT_EXPR. If BB is NULL, then the ASSERT_EXPR is to be inserted
4111 on edge E. Otherwise, if E is NULL, the ASSERT_EXPR is inserted on
4112 BB. If SI points to a COND_EXPR or a SWITCH_EXPR statement, then E
4113 must not be NULL. */
4116 register_new_assert_for (tree name, tree expr,
4117 enum tree_code comp_code,
4121 gimple_stmt_iterator si)
4123 assert_locus_t n, loc, last_loc;
4124 basic_block dest_bb;
4126 gcc_checking_assert (bb == NULL || e == NULL);
4129 gcc_checking_assert (gimple_code (gsi_stmt (si)) != GIMPLE_COND
4130 && gimple_code (gsi_stmt (si)) != GIMPLE_SWITCH);
4132 /* Never build an assert comparing against an integer constant with
4133 TREE_OVERFLOW set. This confuses our undefined overflow warning
4135 if (TREE_CODE (val) == INTEGER_CST
4136 && TREE_OVERFLOW (val))
4137 val = build_int_cst_wide (TREE_TYPE (val),
4138 TREE_INT_CST_LOW (val), TREE_INT_CST_HIGH (val));
4140 /* The new assertion A will be inserted at BB or E. We need to
4141 determine if the new location is dominated by a previously
4142 registered location for A. If we are doing an edge insertion,
4143 assume that A will be inserted at E->DEST. Note that this is not
4146 If E is a critical edge, it will be split. But even if E is
4147 split, the new block will dominate the same set of blocks that
4150 The reverse, however, is not true, blocks dominated by E->DEST
4151 will not be dominated by the new block created to split E. So,
4152 if the insertion location is on a critical edge, we will not use
4153 the new location to move another assertion previously registered
4154 at a block dominated by E->DEST. */
4155 dest_bb = (bb) ? bb : e->dest;
4157 /* If NAME already has an ASSERT_EXPR registered for COMP_CODE and
4158 VAL at a block dominating DEST_BB, then we don't need to insert a new
4159 one. Similarly, if the same assertion already exists at a block
4160 dominated by DEST_BB and the new location is not on a critical
4161 edge, then update the existing location for the assertion (i.e.,
4162 move the assertion up in the dominance tree).
4164 Note, this is implemented as a simple linked list because there
4165 should not be more than a handful of assertions registered per
4166 name. If this becomes a performance problem, a table hashed by
4167 COMP_CODE and VAL could be implemented. */
4168 loc = asserts_for[SSA_NAME_VERSION (name)];
4172 if (loc->comp_code == comp_code
4174 || operand_equal_p (loc->val, val, 0))
4175 && (loc->expr == expr
4176 || operand_equal_p (loc->expr, expr, 0)))
4178 /* If the assertion NAME COMP_CODE VAL has already been
4179 registered at a basic block that dominates DEST_BB, then
4180 we don't need to insert the same assertion again. Note
4181 that we don't check strict dominance here to avoid
4182 replicating the same assertion inside the same basic
4183 block more than once (e.g., when a pointer is
4184 dereferenced several times inside a block).
4186 An exception to this rule are edge insertions. If the
4187 new assertion is to be inserted on edge E, then it will
4188 dominate all the other insertions that we may want to
4189 insert in DEST_BB. So, if we are doing an edge
4190 insertion, don't do this dominance check. */
4192 && dominated_by_p (CDI_DOMINATORS, dest_bb, loc->bb))
4195 /* Otherwise, if E is not a critical edge and DEST_BB
4196 dominates the existing location for the assertion, move
4197 the assertion up in the dominance tree by updating its
4198 location information. */
4199 if ((e == NULL || !EDGE_CRITICAL_P (e))
4200 && dominated_by_p (CDI_DOMINATORS, loc->bb, dest_bb))
4209 /* Update the last node of the list and move to the next one. */
4214 /* If we didn't find an assertion already registered for
4215 NAME COMP_CODE VAL, add a new one at the end of the list of
4216 assertions associated with NAME. */
4217 n = XNEW (struct assert_locus_d);
4221 n->comp_code = comp_code;
4229 asserts_for[SSA_NAME_VERSION (name)] = n;
4231 bitmap_set_bit (need_assert_for, SSA_NAME_VERSION (name));
4234 /* (COND_OP0 COND_CODE COND_OP1) is a predicate which uses NAME.
4235 Extract a suitable test code and value and store them into *CODE_P and
4236 *VAL_P so the predicate is normalized to NAME *CODE_P *VAL_P.
4238 If no extraction was possible, return FALSE, otherwise return TRUE.
4240 If INVERT is true, then we invert the result stored into *CODE_P. */
4243 extract_code_and_val_from_cond_with_ops (tree name, enum tree_code cond_code,
4244 tree cond_op0, tree cond_op1,
4245 bool invert, enum tree_code *code_p,
4248 enum tree_code comp_code;
4251 /* Otherwise, we have a comparison of the form NAME COMP VAL
4252 or VAL COMP NAME. */
4253 if (name == cond_op1)
4255 /* If the predicate is of the form VAL COMP NAME, flip
4256 COMP around because we need to register NAME as the
4257 first operand in the predicate. */
4258 comp_code = swap_tree_comparison (cond_code);
4263 /* The comparison is of the form NAME COMP VAL, so the
4264 comparison code remains unchanged. */
4265 comp_code = cond_code;
4269 /* Invert the comparison code as necessary. */
4271 comp_code = invert_tree_comparison (comp_code, 0);
4273 /* VRP does not handle float types. */
4274 if (SCALAR_FLOAT_TYPE_P (TREE_TYPE (val)))
4277 /* Do not register always-false predicates.
4278 FIXME: this works around a limitation in fold() when dealing with
4279 enumerations. Given 'enum { N1, N2 } x;', fold will not
4280 fold 'if (x > N2)' to 'if (0)'. */
4281 if ((comp_code == GT_EXPR || comp_code == LT_EXPR)
4282 && INTEGRAL_TYPE_P (TREE_TYPE (val)))
4284 tree min = TYPE_MIN_VALUE (TREE_TYPE (val));
4285 tree max = TYPE_MAX_VALUE (TREE_TYPE (val));
4287 if (comp_code == GT_EXPR
4289 || compare_values (val, max) == 0))
4292 if (comp_code == LT_EXPR
4294 || compare_values (val, min) == 0))
4297 *code_p = comp_code;
4302 /* Try to register an edge assertion for SSA name NAME on edge E for
4303 the condition COND contributing to the conditional jump pointed to by BSI.
4304 Invert the condition COND if INVERT is true.
4305 Return true if an assertion for NAME could be registered. */
4308 register_edge_assert_for_2 (tree name, edge e, gimple_stmt_iterator bsi,
4309 enum tree_code cond_code,
4310 tree cond_op0, tree cond_op1, bool invert)
4313 enum tree_code comp_code;
4314 bool retval = false;
4316 if (!extract_code_and_val_from_cond_with_ops (name, cond_code,
4319 invert, &comp_code, &val))
4322 /* Only register an ASSERT_EXPR if NAME was found in the sub-graph
4323 reachable from E. */
4324 if (live_on_edge (e, name)
4325 && !has_single_use (name))
4327 register_new_assert_for (name, name, comp_code, val, NULL, e, bsi);
4331 /* In the case of NAME <= CST and NAME being defined as
4332 NAME = (unsigned) NAME2 + CST2 we can assert NAME2 >= -CST2
4333 and NAME2 <= CST - CST2. We can do the same for NAME > CST.
4334 This catches range and anti-range tests. */
4335 if ((comp_code == LE_EXPR
4336 || comp_code == GT_EXPR)
4337 && TREE_CODE (val) == INTEGER_CST
4338 && TYPE_UNSIGNED (TREE_TYPE (val)))
4340 gimple def_stmt = SSA_NAME_DEF_STMT (name);
4341 tree cst2 = NULL_TREE, name2 = NULL_TREE, name3 = NULL_TREE;
4343 /* Extract CST2 from the (optional) addition. */
4344 if (is_gimple_assign (def_stmt)
4345 && gimple_assign_rhs_code (def_stmt) == PLUS_EXPR)
4347 name2 = gimple_assign_rhs1 (def_stmt);
4348 cst2 = gimple_assign_rhs2 (def_stmt);
4349 if (TREE_CODE (name2) == SSA_NAME
4350 && TREE_CODE (cst2) == INTEGER_CST)
4351 def_stmt = SSA_NAME_DEF_STMT (name2);
4354 /* Extract NAME2 from the (optional) sign-changing cast. */
4355 if (gimple_assign_cast_p (def_stmt))
4357 if (CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (def_stmt))
4358 && ! TYPE_UNSIGNED (TREE_TYPE (gimple_assign_rhs1 (def_stmt)))
4359 && (TYPE_PRECISION (gimple_expr_type (def_stmt))
4360 == TYPE_PRECISION (TREE_TYPE (gimple_assign_rhs1 (def_stmt)))))
4361 name3 = gimple_assign_rhs1 (def_stmt);
4364 /* If name3 is used later, create an ASSERT_EXPR for it. */
4365 if (name3 != NULL_TREE
4366 && TREE_CODE (name3) == SSA_NAME
4367 && (cst2 == NULL_TREE
4368 || TREE_CODE (cst2) == INTEGER_CST)
4369 && INTEGRAL_TYPE_P (TREE_TYPE (name3))
4370 && live_on_edge (e, name3)
4371 && !has_single_use (name3))
4375 /* Build an expression for the range test. */
4376 tmp = build1 (NOP_EXPR, TREE_TYPE (name), name3);
4377 if (cst2 != NULL_TREE)
4378 tmp = build2 (PLUS_EXPR, TREE_TYPE (name), tmp, cst2);
4382 fprintf (dump_file, "Adding assert for ");
4383 print_generic_expr (dump_file, name3, 0);
4384 fprintf (dump_file, " from ");
4385 print_generic_expr (dump_file, tmp, 0);
4386 fprintf (dump_file, "\n");
4389 register_new_assert_for (name3, tmp, comp_code, val, NULL, e, bsi);
4394 /* If name2 is used later, create an ASSERT_EXPR for it. */
4395 if (name2 != NULL_TREE
4396 && TREE_CODE (name2) == SSA_NAME
4397 && TREE_CODE (cst2) == INTEGER_CST
4398 && INTEGRAL_TYPE_P (TREE_TYPE (name2))
4399 && live_on_edge (e, name2)
4400 && !has_single_use (name2))
4404 /* Build an expression for the range test. */
4406 if (TREE_TYPE (name) != TREE_TYPE (name2))
4407 tmp = build1 (NOP_EXPR, TREE_TYPE (name), tmp);
4408 if (cst2 != NULL_TREE)
4409 tmp = build2 (PLUS_EXPR, TREE_TYPE (name), tmp, cst2);
4413 fprintf (dump_file, "Adding assert for ");
4414 print_generic_expr (dump_file, name2, 0);
4415 fprintf (dump_file, " from ");
4416 print_generic_expr (dump_file, tmp, 0);
4417 fprintf (dump_file, "\n");
4420 register_new_assert_for (name2, tmp, comp_code, val, NULL, e, bsi);
4429 /* OP is an operand of a truth value expression which is known to have
4430 a particular value. Register any asserts for OP and for any
4431 operands in OP's defining statement.
4433 If CODE is EQ_EXPR, then we want to register OP is zero (false),
4434 if CODE is NE_EXPR, then we want to register OP is nonzero (true). */
4437 register_edge_assert_for_1 (tree op, enum tree_code code,
4438 edge e, gimple_stmt_iterator bsi)
4440 bool retval = false;
4443 enum tree_code rhs_code;
4445 /* We only care about SSA_NAMEs. */
4446 if (TREE_CODE (op) != SSA_NAME)
4449 /* We know that OP will have a zero or nonzero value. If OP is used
4450 more than once go ahead and register an assert for OP.
4452 The FOUND_IN_SUBGRAPH support is not helpful in this situation as
4453 it will always be set for OP (because OP is used in a COND_EXPR in
4455 if (!has_single_use (op))
4457 val = build_int_cst (TREE_TYPE (op), 0);
4458 register_new_assert_for (op, op, code, val, NULL, e, bsi);
4462 /* Now look at how OP is set. If it's set from a comparison,
4463 a truth operation or some bit operations, then we may be able
4464 to register information about the operands of that assignment. */
4465 op_def = SSA_NAME_DEF_STMT (op);
4466 if (gimple_code (op_def) != GIMPLE_ASSIGN)
4469 rhs_code = gimple_assign_rhs_code (op_def);
4471 if (TREE_CODE_CLASS (rhs_code) == tcc_comparison)
4473 bool invert = (code == EQ_EXPR ? true : false);
4474 tree op0 = gimple_assign_rhs1 (op_def);
4475 tree op1 = gimple_assign_rhs2 (op_def);
4477 if (TREE_CODE (op0) == SSA_NAME)
4478 retval |= register_edge_assert_for_2 (op0, e, bsi, rhs_code, op0, op1,
4480 if (TREE_CODE (op1) == SSA_NAME)
4481 retval |= register_edge_assert_for_2 (op1, e, bsi, rhs_code, op0, op1,
4484 else if ((code == NE_EXPR
4485 && (gimple_assign_rhs_code (op_def) == TRUTH_AND_EXPR
4486 || gimple_assign_rhs_code (op_def) == BIT_AND_EXPR))
4488 && (gimple_assign_rhs_code (op_def) == TRUTH_OR_EXPR
4489 || gimple_assign_rhs_code (op_def) == BIT_IOR_EXPR)))
4491 /* Recurse on each operand. */
4492 retval |= register_edge_assert_for_1 (gimple_assign_rhs1 (op_def),
4494 retval |= register_edge_assert_for_1 (gimple_assign_rhs2 (op_def),
4497 else if (gimple_assign_rhs_code (op_def) == TRUTH_NOT_EXPR)
4499 /* Recurse, flipping CODE. */
4500 code = invert_tree_comparison (code, false);
4501 retval |= register_edge_assert_for_1 (gimple_assign_rhs1 (op_def),
4504 else if (gimple_assign_rhs_code (op_def) == SSA_NAME)
4506 /* Recurse through the copy. */
4507 retval |= register_edge_assert_for_1 (gimple_assign_rhs1 (op_def),
4510 else if (CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (op_def)))
4512 /* Recurse through the type conversion. */
4513 retval |= register_edge_assert_for_1 (gimple_assign_rhs1 (op_def),
4520 /* Try to register an edge assertion for SSA name NAME on edge E for
4521 the condition COND contributing to the conditional jump pointed to by SI.
4522 Return true if an assertion for NAME could be registered. */
4525 register_edge_assert_for (tree name, edge e, gimple_stmt_iterator si,
4526 enum tree_code cond_code, tree cond_op0,
4530 enum tree_code comp_code;
4531 bool retval = false;
4532 bool is_else_edge = (e->flags & EDGE_FALSE_VALUE) != 0;
4534 /* Do not attempt to infer anything in names that flow through
4536 if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (name))
4539 if (!extract_code_and_val_from_cond_with_ops (name, cond_code,
4545 /* Register ASSERT_EXPRs for name. */
4546 retval |= register_edge_assert_for_2 (name, e, si, cond_code, cond_op0,
4547 cond_op1, is_else_edge);
4550 /* If COND is effectively an equality test of an SSA_NAME against
4551 the value zero or one, then we may be able to assert values
4552 for SSA_NAMEs which flow into COND. */
4554 /* In the case of NAME == 1 or NAME != 0, for TRUTH_AND_EXPR defining
4555 statement of NAME we can assert both operands of the TRUTH_AND_EXPR
4556 have nonzero value. */
4557 if (((comp_code == EQ_EXPR && integer_onep (val))
4558 || (comp_code == NE_EXPR && integer_zerop (val))))
4560 gimple def_stmt = SSA_NAME_DEF_STMT (name);
4562 if (is_gimple_assign (def_stmt)
4563 && (gimple_assign_rhs_code (def_stmt) == TRUTH_AND_EXPR
4564 || gimple_assign_rhs_code (def_stmt) == BIT_AND_EXPR))
4566 tree op0 = gimple_assign_rhs1 (def_stmt);
4567 tree op1 = gimple_assign_rhs2 (def_stmt);
4568 retval |= register_edge_assert_for_1 (op0, NE_EXPR, e, si);
4569 retval |= register_edge_assert_for_1 (op1, NE_EXPR, e, si);
4573 /* In the case of NAME == 0 or NAME != 1, for TRUTH_OR_EXPR defining
4574 statement of NAME we can assert both operands of the TRUTH_OR_EXPR
4576 if (((comp_code == EQ_EXPR && integer_zerop (val))
4577 || (comp_code == NE_EXPR && integer_onep (val))))
4579 gimple def_stmt = SSA_NAME_DEF_STMT (name);
4581 if (is_gimple_assign (def_stmt)
4582 && (gimple_assign_rhs_code (def_stmt) == TRUTH_OR_EXPR
4583 /* For BIT_IOR_EXPR only if NAME == 0 both operands have
4584 necessarily zero value. */
4585 || (comp_code == EQ_EXPR
4586 && (gimple_assign_rhs_code (def_stmt) == BIT_IOR_EXPR))))
4588 tree op0 = gimple_assign_rhs1 (def_stmt);
4589 tree op1 = gimple_assign_rhs2 (def_stmt);
4590 retval |= register_edge_assert_for_1 (op0, EQ_EXPR, e, si);
4591 retval |= register_edge_assert_for_1 (op1, EQ_EXPR, e, si);
4599 /* Determine whether the outgoing edges of BB should receive an
4600 ASSERT_EXPR for each of the operands of BB's LAST statement.
4601 The last statement of BB must be a COND_EXPR.
4603 If any of the sub-graphs rooted at BB have an interesting use of
4604 the predicate operands, an assert location node is added to the
4605 list of assertions for the corresponding operands. */
4608 find_conditional_asserts (basic_block bb, gimple last)
4611 gimple_stmt_iterator bsi;
4617 need_assert = false;
4618 bsi = gsi_for_stmt (last);
4620 /* Look for uses of the operands in each of the sub-graphs
4621 rooted at BB. We need to check each of the outgoing edges
4622 separately, so that we know what kind of ASSERT_EXPR to
4624 FOR_EACH_EDGE (e, ei, bb->succs)
4629 /* Register the necessary assertions for each operand in the
4630 conditional predicate. */
4631 FOR_EACH_SSA_TREE_OPERAND (op, last, iter, SSA_OP_USE)
4633 need_assert |= register_edge_assert_for (op, e, bsi,
4634 gimple_cond_code (last),
4635 gimple_cond_lhs (last),
4636 gimple_cond_rhs (last));
4643 /* Compare two case labels sorting first by the destination label uid
4644 and then by the case value. */
4647 compare_case_labels (const void *p1, const void *p2)
4649 const_tree const case1 = *(const_tree const*)p1;
4650 const_tree const case2 = *(const_tree const*)p2;
4651 unsigned int uid1 = DECL_UID (CASE_LABEL (case1));
4652 unsigned int uid2 = DECL_UID (CASE_LABEL (case2));
4656 else if (uid1 == uid2)
4658 /* Make sure the default label is first in a group. */
4659 if (!CASE_LOW (case1))
4661 else if (!CASE_LOW (case2))
4664 return tree_int_cst_compare (CASE_LOW (case1), CASE_LOW (case2));
4670 /* Determine whether the outgoing edges of BB should receive an
4671 ASSERT_EXPR for each of the operands of BB's LAST statement.
4672 The last statement of BB must be a SWITCH_EXPR.
4674 If any of the sub-graphs rooted at BB have an interesting use of
4675 the predicate operands, an assert location node is added to the
4676 list of assertions for the corresponding operands. */
4679 find_switch_asserts (basic_block bb, gimple last)
4682 gimple_stmt_iterator bsi;
4686 size_t n = gimple_switch_num_labels(last);
4687 #if GCC_VERSION >= 4000
4690 /* Work around GCC 3.4 bug (PR 37086). */
4691 volatile unsigned int idx;
4694 need_assert = false;
4695 bsi = gsi_for_stmt (last);
4696 op = gimple_switch_index (last);
4697 if (TREE_CODE (op) != SSA_NAME)
4700 /* Build a vector of case labels sorted by destination label. */
4701 vec2 = make_tree_vec (n);
4702 for (idx = 0; idx < n; ++idx)
4703 TREE_VEC_ELT (vec2, idx) = gimple_switch_label (last, idx);
4704 qsort (&TREE_VEC_ELT (vec2, 0), n, sizeof (tree), compare_case_labels);
4706 for (idx = 0; idx < n; ++idx)
4709 tree cl = TREE_VEC_ELT (vec2, idx);
4711 min = CASE_LOW (cl);
4712 max = CASE_HIGH (cl);
4714 /* If there are multiple case labels with the same destination
4715 we need to combine them to a single value range for the edge. */
4717 && CASE_LABEL (cl) == CASE_LABEL (TREE_VEC_ELT (vec2, idx + 1)))
4719 /* Skip labels until the last of the group. */
4723 && CASE_LABEL (cl) == CASE_LABEL (TREE_VEC_ELT (vec2, idx)));
4726 /* Pick up the maximum of the case label range. */
4727 if (CASE_HIGH (TREE_VEC_ELT (vec2, idx)))
4728 max = CASE_HIGH (TREE_VEC_ELT (vec2, idx));
4730 max = CASE_LOW (TREE_VEC_ELT (vec2, idx));
4733 /* Nothing to do if the range includes the default label until we
4734 can register anti-ranges. */
4735 if (min == NULL_TREE)
4738 /* Find the edge to register the assert expr on. */
4739 e = find_edge (bb, label_to_block (CASE_LABEL (cl)));
4741 /* Register the necessary assertions for the operand in the
4743 need_assert |= register_edge_assert_for (op, e, bsi,
4744 max ? GE_EXPR : EQ_EXPR,
4746 fold_convert (TREE_TYPE (op),
4750 need_assert |= register_edge_assert_for (op, e, bsi, LE_EXPR,
4752 fold_convert (TREE_TYPE (op),
4761 /* Traverse all the statements in block BB looking for statements that
4762 may generate useful assertions for the SSA names in their operand.
4763 If a statement produces a useful assertion A for name N_i, then the
4764 list of assertions already generated for N_i is scanned to
4765 determine if A is actually needed.
4767 If N_i already had the assertion A at a location dominating the
4768 current location, then nothing needs to be done. Otherwise, the
4769 new location for A is recorded instead.
4771 1- For every statement S in BB, all the variables used by S are
4772 added to bitmap FOUND_IN_SUBGRAPH.
4774 2- If statement S uses an operand N in a way that exposes a known
4775 value range for N, then if N was not already generated by an
4776 ASSERT_EXPR, create a new assert location for N. For instance,
4777 if N is a pointer and the statement dereferences it, we can
4778 assume that N is not NULL.
4780 3- COND_EXPRs are a special case of #2. We can derive range
4781 information from the predicate but need to insert different
4782 ASSERT_EXPRs for each of the sub-graphs rooted at the
4783 conditional block. If the last statement of BB is a conditional
4784 expression of the form 'X op Y', then
4786 a) Remove X and Y from the set FOUND_IN_SUBGRAPH.
4788 b) If the conditional is the only entry point to the sub-graph
4789 corresponding to the THEN_CLAUSE, recurse into it. On
4790 return, if X and/or Y are marked in FOUND_IN_SUBGRAPH, then
4791 an ASSERT_EXPR is added for the corresponding variable.
4793 c) Repeat step (b) on the ELSE_CLAUSE.
4795 d) Mark X and Y in FOUND_IN_SUBGRAPH.
4804 In this case, an assertion on the THEN clause is useful to
4805 determine that 'a' is always 9 on that edge. However, an assertion
4806 on the ELSE clause would be unnecessary.
4808 4- If BB does not end in a conditional expression, then we recurse
4809 into BB's dominator children.
4811 At the end of the recursive traversal, every SSA name will have a
4812 list of locations where ASSERT_EXPRs should be added. When a new
4813 location for name N is found, it is registered by calling
4814 register_new_assert_for. That function keeps track of all the
4815 registered assertions to prevent adding unnecessary assertions.
4816 For instance, if a pointer P_4 is dereferenced more than once in a
4817 dominator tree, only the location dominating all the dereference of
4818 P_4 will receive an ASSERT_EXPR.
4820 If this function returns true, then it means that there are names
4821 for which we need to generate ASSERT_EXPRs. Those assertions are
4822 inserted by process_assert_insertions. */
4825 find_assert_locations_1 (basic_block bb, sbitmap live)
4827 gimple_stmt_iterator si;
4832 need_assert = false;
4833 last = last_stmt (bb);
4835 /* If BB's last statement is a conditional statement involving integer
4836 operands, determine if we need to add ASSERT_EXPRs. */
4838 && gimple_code (last) == GIMPLE_COND
4839 && !fp_predicate (last)
4840 && !ZERO_SSA_OPERANDS (last, SSA_OP_USE))
4841 need_assert |= find_conditional_asserts (bb, last);
4843 /* If BB's last statement is a switch statement involving integer
4844 operands, determine if we need to add ASSERT_EXPRs. */
4846 && gimple_code (last) == GIMPLE_SWITCH
4847 && !ZERO_SSA_OPERANDS (last, SSA_OP_USE))
4848 need_assert |= find_switch_asserts (bb, last);
4850 /* Traverse all the statements in BB marking used names and looking
4851 for statements that may infer assertions for their used operands. */
4852 for (si = gsi_start_bb (bb); !gsi_end_p (si); gsi_next (&si))
4858 stmt = gsi_stmt (si);
4860 if (is_gimple_debug (stmt))
4863 /* See if we can derive an assertion for any of STMT's operands. */
4864 FOR_EACH_SSA_TREE_OPERAND (op, stmt, i, SSA_OP_USE)
4867 enum tree_code comp_code;
4869 /* Mark OP in our live bitmap. */
4870 SET_BIT (live, SSA_NAME_VERSION (op));
4872 /* If OP is used in such a way that we can infer a value
4873 range for it, and we don't find a previous assertion for
4874 it, create a new assertion location node for OP. */
4875 if (infer_value_range (stmt, op, &comp_code, &value))
4877 /* If we are able to infer a nonzero value range for OP,
4878 then walk backwards through the use-def chain to see if OP
4879 was set via a typecast.
4881 If so, then we can also infer a nonzero value range
4882 for the operand of the NOP_EXPR. */
4883 if (comp_code == NE_EXPR && integer_zerop (value))
4886 gimple def_stmt = SSA_NAME_DEF_STMT (t);
4888 while (is_gimple_assign (def_stmt)
4889 && gimple_assign_rhs_code (def_stmt) == NOP_EXPR
4891 (gimple_assign_rhs1 (def_stmt)) == SSA_NAME
4893 (TREE_TYPE (gimple_assign_rhs1 (def_stmt))))
4895 t = gimple_assign_rhs1 (def_stmt);
4896 def_stmt = SSA_NAME_DEF_STMT (t);
4898 /* Note we want to register the assert for the
4899 operand of the NOP_EXPR after SI, not after the
4901 if (! has_single_use (t))
4903 register_new_assert_for (t, t, comp_code, value,
4910 /* If OP is used only once, namely in this STMT, don't
4911 bother creating an ASSERT_EXPR for it. Such an
4912 ASSERT_EXPR would do nothing but increase compile time. */
4913 if (!has_single_use (op))
4915 register_new_assert_for (op, op, comp_code, value,
4923 /* Traverse all PHI nodes in BB marking used operands. */
4924 for (si = gsi_start_phis (bb); !gsi_end_p(si); gsi_next (&si))
4926 use_operand_p arg_p;
4928 phi = gsi_stmt (si);
4930 FOR_EACH_PHI_ARG (arg_p, phi, i, SSA_OP_USE)
4932 tree arg = USE_FROM_PTR (arg_p);
4933 if (TREE_CODE (arg) == SSA_NAME)
4934 SET_BIT (live, SSA_NAME_VERSION (arg));
4941 /* Do an RPO walk over the function computing SSA name liveness
4942 on-the-fly and deciding on assert expressions to insert.
4943 Returns true if there are assert expressions to be inserted. */
4946 find_assert_locations (void)
4948 int *rpo = XCNEWVEC (int, last_basic_block + NUM_FIXED_BLOCKS);
4949 int *bb_rpo = XCNEWVEC (int, last_basic_block + NUM_FIXED_BLOCKS);
4950 int *last_rpo = XCNEWVEC (int, last_basic_block + NUM_FIXED_BLOCKS);
4954 live = XCNEWVEC (sbitmap, last_basic_block + NUM_FIXED_BLOCKS);
4955 rpo_cnt = pre_and_rev_post_order_compute (NULL, rpo, false);
4956 for (i = 0; i < rpo_cnt; ++i)
4959 need_asserts = false;
4960 for (i = rpo_cnt-1; i >= 0; --i)
4962 basic_block bb = BASIC_BLOCK (rpo[i]);
4968 live[rpo[i]] = sbitmap_alloc (num_ssa_names);
4969 sbitmap_zero (live[rpo[i]]);
4972 /* Process BB and update the live information with uses in
4974 need_asserts |= find_assert_locations_1 (bb, live[rpo[i]]);
4976 /* Merge liveness into the predecessor blocks and free it. */
4977 if (!sbitmap_empty_p (live[rpo[i]]))
4980 FOR_EACH_EDGE (e, ei, bb->preds)
4982 int pred = e->src->index;
4983 if (e->flags & EDGE_DFS_BACK)
4988 live[pred] = sbitmap_alloc (num_ssa_names);
4989 sbitmap_zero (live[pred]);
4991 sbitmap_a_or_b (live[pred], live[pred], live[rpo[i]]);
4993 if (bb_rpo[pred] < pred_rpo)
4994 pred_rpo = bb_rpo[pred];
4997 /* Record the RPO number of the last visited block that needs
4998 live information from this block. */
4999 last_rpo[rpo[i]] = pred_rpo;
5003 sbitmap_free (live[rpo[i]]);
5004 live[rpo[i]] = NULL;
5007 /* We can free all successors live bitmaps if all their
5008 predecessors have been visited already. */
5009 FOR_EACH_EDGE (e, ei, bb->succs)
5010 if (last_rpo[e->dest->index] == i
5011 && live[e->dest->index])
5013 sbitmap_free (live[e->dest->index]);
5014 live[e->dest->index] = NULL;
5019 XDELETEVEC (bb_rpo);
5020 XDELETEVEC (last_rpo);
5021 for (i = 0; i < last_basic_block + NUM_FIXED_BLOCKS; ++i)
5023 sbitmap_free (live[i]);
5026 return need_asserts;
5029 /* Create an ASSERT_EXPR for NAME and insert it in the location
5030 indicated by LOC. Return true if we made any edge insertions. */
5033 process_assert_insertions_for (tree name, assert_locus_t loc)
5035 /* Build the comparison expression NAME_i COMP_CODE VAL. */
5042 /* If we have X <=> X do not insert an assert expr for that. */
5043 if (loc->expr == loc->val)
5046 cond = build2 (loc->comp_code, boolean_type_node, loc->expr, loc->val);
5047 assert_stmt = build_assert_expr_for (cond, name);
5050 /* We have been asked to insert the assertion on an edge. This
5051 is used only by COND_EXPR and SWITCH_EXPR assertions. */
5052 gcc_checking_assert (gimple_code (gsi_stmt (loc->si)) == GIMPLE_COND
5053 || (gimple_code (gsi_stmt (loc->si))
5056 gsi_insert_on_edge (loc->e, assert_stmt);
5060 /* Otherwise, we can insert right after LOC->SI iff the
5061 statement must not be the last statement in the block. */
5062 stmt = gsi_stmt (loc->si);
5063 if (!stmt_ends_bb_p (stmt))
5065 gsi_insert_after (&loc->si, assert_stmt, GSI_SAME_STMT);
5069 /* If STMT must be the last statement in BB, we can only insert new
5070 assertions on the non-abnormal edge out of BB. Note that since
5071 STMT is not control flow, there may only be one non-abnormal edge
5073 FOR_EACH_EDGE (e, ei, loc->bb->succs)
5074 if (!(e->flags & EDGE_ABNORMAL))
5076 gsi_insert_on_edge (e, assert_stmt);
5084 /* Process all the insertions registered for every name N_i registered
5085 in NEED_ASSERT_FOR. The list of assertions to be inserted are
5086 found in ASSERTS_FOR[i]. */
5089 process_assert_insertions (void)
5093 bool update_edges_p = false;
5094 int num_asserts = 0;
5096 if (dump_file && (dump_flags & TDF_DETAILS))
5097 dump_all_asserts (dump_file);
5099 EXECUTE_IF_SET_IN_BITMAP (need_assert_for, 0, i, bi)
5101 assert_locus_t loc = asserts_for[i];
5106 assert_locus_t next = loc->next;
5107 update_edges_p |= process_assert_insertions_for (ssa_name (i), loc);
5115 gsi_commit_edge_inserts ();
5117 statistics_counter_event (cfun, "Number of ASSERT_EXPR expressions inserted",
5122 /* Traverse the flowgraph looking for conditional jumps to insert range
5123 expressions. These range expressions are meant to provide information
5124 to optimizations that need to reason in terms of value ranges. They
5125 will not be expanded into RTL. For instance, given:
5134 this pass will transform the code into:
5140 x = ASSERT_EXPR <x, x < y>
5145 y = ASSERT_EXPR <y, x <= y>
5149 The idea is that once copy and constant propagation have run, other
5150 optimizations will be able to determine what ranges of values can 'x'
5151 take in different paths of the code, simply by checking the reaching
5152 definition of 'x'. */
5155 insert_range_assertions (void)
5157 need_assert_for = BITMAP_ALLOC (NULL);
5158 asserts_for = XCNEWVEC (assert_locus_t, num_ssa_names);
5160 calculate_dominance_info (CDI_DOMINATORS);
5162 if (find_assert_locations ())
5164 process_assert_insertions ();
5165 update_ssa (TODO_update_ssa_no_phi);
5168 if (dump_file && (dump_flags & TDF_DETAILS))
5170 fprintf (dump_file, "\nSSA form after inserting ASSERT_EXPRs\n");
5171 dump_function_to_file (current_function_decl, dump_file, dump_flags);
5175 BITMAP_FREE (need_assert_for);
5178 /* Checks one ARRAY_REF in REF, located at LOCUS. Ignores flexible arrays
5179 and "struct" hacks. If VRP can determine that the
5180 array subscript is a constant, check if it is outside valid
5181 range. If the array subscript is a RANGE, warn if it is
5182 non-overlapping with valid range.
5183 IGNORE_OFF_BY_ONE is true if the ARRAY_REF is inside a ADDR_EXPR. */
5186 check_array_ref (location_t location, tree ref, bool ignore_off_by_one)
5188 value_range_t* vr = NULL;
5189 tree low_sub, up_sub;
5190 tree low_bound, up_bound, up_bound_p1;
5193 if (TREE_NO_WARNING (ref))
5196 low_sub = up_sub = TREE_OPERAND (ref, 1);
5197 up_bound = array_ref_up_bound (ref);
5199 /* Can not check flexible arrays. */
5201 || TREE_CODE (up_bound) != INTEGER_CST)
5204 /* Accesses to trailing arrays via pointers may access storage
5205 beyond the types array bounds. */
5206 base = get_base_address (ref);
5207 if (base && TREE_CODE (base) == MEM_REF)
5209 tree cref, next = NULL_TREE;
5211 if (TREE_CODE (TREE_OPERAND (ref, 0)) != COMPONENT_REF)
5214 cref = TREE_OPERAND (ref, 0);
5215 if (TREE_CODE (TREE_TYPE (TREE_OPERAND (cref, 0))) == RECORD_TYPE)
5216 for (next = DECL_CHAIN (TREE_OPERAND (cref, 1));
5217 next && TREE_CODE (next) != FIELD_DECL;
5218 next = DECL_CHAIN (next))
5221 /* If this is the last field in a struct type or a field in a
5222 union type do not warn. */
5227 low_bound = array_ref_low_bound (ref);
5228 up_bound_p1 = int_const_binop (PLUS_EXPR, up_bound, integer_one_node, 0);
5230 if (TREE_CODE (low_sub) == SSA_NAME)
5232 vr = get_value_range (low_sub);
5233 if (vr->type == VR_RANGE || vr->type == VR_ANTI_RANGE)
5235 low_sub = vr->type == VR_RANGE ? vr->max : vr->min;
5236 up_sub = vr->type == VR_RANGE ? vr->min : vr->max;
5240 if (vr && vr->type == VR_ANTI_RANGE)
5242 if (TREE_CODE (up_sub) == INTEGER_CST
5243 && tree_int_cst_lt (up_bound, up_sub)
5244 && TREE_CODE (low_sub) == INTEGER_CST
5245 && tree_int_cst_lt (low_sub, low_bound))
5247 warning_at (location, OPT_Warray_bounds,
5248 "array subscript is outside array bounds");
5249 TREE_NO_WARNING (ref) = 1;
5252 else if (TREE_CODE (up_sub) == INTEGER_CST
5253 && (ignore_off_by_one
5254 ? (tree_int_cst_lt (up_bound, up_sub)
5255 && !tree_int_cst_equal (up_bound_p1, up_sub))
5256 : (tree_int_cst_lt (up_bound, up_sub)
5257 || tree_int_cst_equal (up_bound_p1, up_sub))))
5259 warning_at (location, OPT_Warray_bounds,
5260 "array subscript is above array bounds");
5261 TREE_NO_WARNING (ref) = 1;
5263 else if (TREE_CODE (low_sub) == INTEGER_CST
5264 && tree_int_cst_lt (low_sub, low_bound))
5266 warning_at (location, OPT_Warray_bounds,
5267 "array subscript is below array bounds");
5268 TREE_NO_WARNING (ref) = 1;
5272 /* Searches if the expr T, located at LOCATION computes
5273 address of an ARRAY_REF, and call check_array_ref on it. */
5276 search_for_addr_array (tree t, location_t location)
5278 while (TREE_CODE (t) == SSA_NAME)
5280 gimple g = SSA_NAME_DEF_STMT (t);
5282 if (gimple_code (g) != GIMPLE_ASSIGN)
5285 if (get_gimple_rhs_class (gimple_assign_rhs_code (g))
5286 != GIMPLE_SINGLE_RHS)
5289 t = gimple_assign_rhs1 (g);
5293 /* We are only interested in addresses of ARRAY_REF's. */
5294 if (TREE_CODE (t) != ADDR_EXPR)
5297 /* Check each ARRAY_REFs in the reference chain. */
5300 if (TREE_CODE (t) == ARRAY_REF)
5301 check_array_ref (location, t, true /*ignore_off_by_one*/);
5303 t = TREE_OPERAND (t, 0);
5305 while (handled_component_p (t));
5307 if (TREE_CODE (t) == MEM_REF
5308 && TREE_CODE (TREE_OPERAND (t, 0)) == ADDR_EXPR
5309 && !TREE_NO_WARNING (t))
5311 tree tem = TREE_OPERAND (TREE_OPERAND (t, 0), 0);
5312 tree low_bound, up_bound, el_sz;
5314 if (TREE_CODE (TREE_TYPE (tem)) != ARRAY_TYPE
5315 || TREE_CODE (TREE_TYPE (TREE_TYPE (tem))) == ARRAY_TYPE
5316 || !TYPE_DOMAIN (TREE_TYPE (tem)))
5319 low_bound = TYPE_MIN_VALUE (TYPE_DOMAIN (TREE_TYPE (tem)));
5320 up_bound = TYPE_MAX_VALUE (TYPE_DOMAIN (TREE_TYPE (tem)));
5321 el_sz = TYPE_SIZE_UNIT (TREE_TYPE (TREE_TYPE (tem)));
5323 || TREE_CODE (low_bound) != INTEGER_CST
5325 || TREE_CODE (up_bound) != INTEGER_CST
5327 || TREE_CODE (el_sz) != INTEGER_CST)
5330 idx = mem_ref_offset (t);
5331 idx = double_int_sdiv (idx, tree_to_double_int (el_sz), TRUNC_DIV_EXPR);
5332 if (double_int_scmp (idx, double_int_zero) < 0)
5334 warning_at (location, OPT_Warray_bounds,
5335 "array subscript is below array bounds");
5336 TREE_NO_WARNING (t) = 1;
5338 else if (double_int_scmp (idx,
5341 (tree_to_double_int (up_bound),
5343 (tree_to_double_int (low_bound))),
5344 double_int_one)) > 0)
5346 warning_at (location, OPT_Warray_bounds,
5347 "array subscript is above array bounds");
5348 TREE_NO_WARNING (t) = 1;
5353 /* walk_tree() callback that checks if *TP is
5354 an ARRAY_REF inside an ADDR_EXPR (in which an array
5355 subscript one outside the valid range is allowed). Call
5356 check_array_ref for each ARRAY_REF found. The location is
5360 check_array_bounds (tree *tp, int *walk_subtree, void *data)
5363 struct walk_stmt_info *wi = (struct walk_stmt_info *) data;
5364 location_t location;
5366 if (EXPR_HAS_LOCATION (t))
5367 location = EXPR_LOCATION (t);
5370 location_t *locp = (location_t *) wi->info;
5374 *walk_subtree = TRUE;
5376 if (TREE_CODE (t) == ARRAY_REF)
5377 check_array_ref (location, t, false /*ignore_off_by_one*/);
5379 if (TREE_CODE (t) == MEM_REF
5380 || (TREE_CODE (t) == RETURN_EXPR && TREE_OPERAND (t, 0)))
5381 search_for_addr_array (TREE_OPERAND (t, 0), location);
5383 if (TREE_CODE (t) == ADDR_EXPR)
5384 *walk_subtree = FALSE;
5389 /* Walk over all statements of all reachable BBs and call check_array_bounds
5393 check_all_array_refs (void)
5396 gimple_stmt_iterator si;
5402 bool executable = false;
5404 /* Skip blocks that were found to be unreachable. */
5405 FOR_EACH_EDGE (e, ei, bb->preds)
5406 executable |= !!(e->flags & EDGE_EXECUTABLE);
5410 for (si = gsi_start_bb (bb); !gsi_end_p (si); gsi_next (&si))
5412 gimple stmt = gsi_stmt (si);
5413 struct walk_stmt_info wi;
5414 if (!gimple_has_location (stmt))
5417 if (is_gimple_call (stmt))
5420 size_t n = gimple_call_num_args (stmt);
5421 for (i = 0; i < n; i++)
5423 tree arg = gimple_call_arg (stmt, i);
5424 search_for_addr_array (arg, gimple_location (stmt));
5429 memset (&wi, 0, sizeof (wi));
5430 wi.info = CONST_CAST (void *, (const void *)
5431 gimple_location_ptr (stmt));
5433 walk_gimple_op (gsi_stmt (si),
5441 /* Convert range assertion expressions into the implied copies and
5442 copy propagate away the copies. Doing the trivial copy propagation
5443 here avoids the need to run the full copy propagation pass after
5446 FIXME, this will eventually lead to copy propagation removing the
5447 names that had useful range information attached to them. For
5448 instance, if we had the assertion N_i = ASSERT_EXPR <N_j, N_j > 3>,
5449 then N_i will have the range [3, +INF].
5451 However, by converting the assertion into the implied copy
5452 operation N_i = N_j, we will then copy-propagate N_j into the uses
5453 of N_i and lose the range information. We may want to hold on to
5454 ASSERT_EXPRs a little while longer as the ranges could be used in
5455 things like jump threading.
5457 The problem with keeping ASSERT_EXPRs around is that passes after
5458 VRP need to handle them appropriately.
5460 Another approach would be to make the range information a first
5461 class property of the SSA_NAME so that it can be queried from
5462 any pass. This is made somewhat more complex by the need for
5463 multiple ranges to be associated with one SSA_NAME. */
5466 remove_range_assertions (void)
5469 gimple_stmt_iterator si;
5471 /* Note that the BSI iterator bump happens at the bottom of the
5472 loop and no bump is necessary if we're removing the statement
5473 referenced by the current BSI. */
5475 for (si = gsi_start_bb (bb); !gsi_end_p (si);)
5477 gimple stmt = gsi_stmt (si);
5480 if (is_gimple_assign (stmt)
5481 && gimple_assign_rhs_code (stmt) == ASSERT_EXPR)
5483 tree rhs = gimple_assign_rhs1 (stmt);
5485 tree cond = fold (ASSERT_EXPR_COND (rhs));
5486 use_operand_p use_p;
5487 imm_use_iterator iter;
5489 gcc_assert (cond != boolean_false_node);
5491 /* Propagate the RHS into every use of the LHS. */
5492 var = ASSERT_EXPR_VAR (rhs);
5493 FOR_EACH_IMM_USE_STMT (use_stmt, iter,
5494 gimple_assign_lhs (stmt))
5495 FOR_EACH_IMM_USE_ON_STMT (use_p, iter)
5497 SET_USE (use_p, var);
5498 gcc_assert (TREE_CODE (var) == SSA_NAME);
5501 /* And finally, remove the copy, it is not needed. */
5502 gsi_remove (&si, true);
5503 release_defs (stmt);
5511 /* Return true if STMT is interesting for VRP. */
5514 stmt_interesting_for_vrp (gimple stmt)
5516 if (gimple_code (stmt) == GIMPLE_PHI
5517 && is_gimple_reg (gimple_phi_result (stmt))
5518 && (INTEGRAL_TYPE_P (TREE_TYPE (gimple_phi_result (stmt)))
5519 || POINTER_TYPE_P (TREE_TYPE (gimple_phi_result (stmt)))))
5521 else if (is_gimple_assign (stmt) || is_gimple_call (stmt))
5523 tree lhs = gimple_get_lhs (stmt);
5525 /* In general, assignments with virtual operands are not useful
5526 for deriving ranges, with the obvious exception of calls to
5527 builtin functions. */
5528 if (lhs && TREE_CODE (lhs) == SSA_NAME
5529 && (INTEGRAL_TYPE_P (TREE_TYPE (lhs))
5530 || POINTER_TYPE_P (TREE_TYPE (lhs)))
5531 && ((is_gimple_call (stmt)
5532 && gimple_call_fndecl (stmt) != NULL_TREE
5533 && DECL_IS_BUILTIN (gimple_call_fndecl (stmt)))
5534 || !gimple_vuse (stmt)))
5537 else if (gimple_code (stmt) == GIMPLE_COND
5538 || gimple_code (stmt) == GIMPLE_SWITCH)
5545 /* Initialize local data structures for VRP. */
5548 vrp_initialize (void)
5552 vr_value = XCNEWVEC (value_range_t *, num_ssa_names);
5553 vr_phi_edge_counts = XCNEWVEC (int, num_ssa_names);
5557 gimple_stmt_iterator si;
5559 for (si = gsi_start_phis (bb); !gsi_end_p (si); gsi_next (&si))
5561 gimple phi = gsi_stmt (si);
5562 if (!stmt_interesting_for_vrp (phi))
5564 tree lhs = PHI_RESULT (phi);
5565 set_value_range_to_varying (get_value_range (lhs));
5566 prop_set_simulate_again (phi, false);
5569 prop_set_simulate_again (phi, true);
5572 for (si = gsi_start_bb (bb); !gsi_end_p (si); gsi_next (&si))
5574 gimple stmt = gsi_stmt (si);
5576 /* If the statement is a control insn, then we do not
5577 want to avoid simulating the statement once. Failure
5578 to do so means that those edges will never get added. */
5579 if (stmt_ends_bb_p (stmt))
5580 prop_set_simulate_again (stmt, true);
5581 else if (!stmt_interesting_for_vrp (stmt))
5585 FOR_EACH_SSA_TREE_OPERAND (def, stmt, i, SSA_OP_DEF)
5586 set_value_range_to_varying (get_value_range (def));
5587 prop_set_simulate_again (stmt, false);
5590 prop_set_simulate_again (stmt, true);
5596 /* Visit assignment STMT. If it produces an interesting range, record
5597 the SSA name in *OUTPUT_P. */
5599 static enum ssa_prop_result
5600 vrp_visit_assignment_or_call (gimple stmt, tree *output_p)
5604 enum gimple_code code = gimple_code (stmt);
5605 lhs = gimple_get_lhs (stmt);
5607 /* We only keep track of ranges in integral and pointer types. */
5608 if (TREE_CODE (lhs) == SSA_NAME
5609 && ((INTEGRAL_TYPE_P (TREE_TYPE (lhs))
5610 /* It is valid to have NULL MIN/MAX values on a type. See
5611 build_range_type. */
5612 && TYPE_MIN_VALUE (TREE_TYPE (lhs))
5613 && TYPE_MAX_VALUE (TREE_TYPE (lhs)))
5614 || POINTER_TYPE_P (TREE_TYPE (lhs))))
5616 value_range_t new_vr = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
5618 if (code == GIMPLE_CALL)
5619 extract_range_basic (&new_vr, stmt);
5621 extract_range_from_assignment (&new_vr, stmt);
5623 if (update_value_range (lhs, &new_vr))
5627 if (dump_file && (dump_flags & TDF_DETAILS))
5629 fprintf (dump_file, "Found new range for ");
5630 print_generic_expr (dump_file, lhs, 0);
5631 fprintf (dump_file, ": ");
5632 dump_value_range (dump_file, &new_vr);
5633 fprintf (dump_file, "\n\n");
5636 if (new_vr.type == VR_VARYING)
5637 return SSA_PROP_VARYING;
5639 return SSA_PROP_INTERESTING;
5642 return SSA_PROP_NOT_INTERESTING;
5645 /* Every other statement produces no useful ranges. */
5646 FOR_EACH_SSA_TREE_OPERAND (def, stmt, iter, SSA_OP_DEF)
5647 set_value_range_to_varying (get_value_range (def));
5649 return SSA_PROP_VARYING;
5652 /* Helper that gets the value range of the SSA_NAME with version I
5653 or a symbolic range containing the SSA_NAME only if the value range
5654 is varying or undefined. */
5656 static inline value_range_t
5657 get_vr_for_comparison (int i)
5659 value_range_t vr = *(vr_value[i]);
5661 /* If name N_i does not have a valid range, use N_i as its own
5662 range. This allows us to compare against names that may
5663 have N_i in their ranges. */
5664 if (vr.type == VR_VARYING || vr.type == VR_UNDEFINED)
5667 vr.min = ssa_name (i);
5668 vr.max = ssa_name (i);
5674 /* Compare all the value ranges for names equivalent to VAR with VAL
5675 using comparison code COMP. Return the same value returned by
5676 compare_range_with_value, including the setting of
5677 *STRICT_OVERFLOW_P. */
5680 compare_name_with_value (enum tree_code comp, tree var, tree val,
5681 bool *strict_overflow_p)
5687 int used_strict_overflow;
5689 value_range_t equiv_vr;
5691 /* Get the set of equivalences for VAR. */
5692 e = get_value_range (var)->equiv;
5694 /* Start at -1. Set it to 0 if we do a comparison without relying
5695 on overflow, or 1 if all comparisons rely on overflow. */
5696 used_strict_overflow = -1;
5698 /* Compare vars' value range with val. */
5699 equiv_vr = get_vr_for_comparison (SSA_NAME_VERSION (var));
5701 retval = compare_range_with_value (comp, &equiv_vr, val, &sop);
5703 used_strict_overflow = sop ? 1 : 0;
5705 /* If the equiv set is empty we have done all work we need to do. */
5709 && used_strict_overflow > 0)
5710 *strict_overflow_p = true;
5714 EXECUTE_IF_SET_IN_BITMAP (e, 0, i, bi)
5716 equiv_vr = get_vr_for_comparison (i);
5718 t = compare_range_with_value (comp, &equiv_vr, val, &sop);
5721 /* If we get different answers from different members
5722 of the equivalence set this check must be in a dead
5723 code region. Folding it to a trap representation
5724 would be correct here. For now just return don't-know. */
5734 used_strict_overflow = 0;
5735 else if (used_strict_overflow < 0)
5736 used_strict_overflow = 1;
5741 && used_strict_overflow > 0)
5742 *strict_overflow_p = true;
5748 /* Given a comparison code COMP and names N1 and N2, compare all the
5749 ranges equivalent to N1 against all the ranges equivalent to N2
5750 to determine the value of N1 COMP N2. Return the same value
5751 returned by compare_ranges. Set *STRICT_OVERFLOW_P to indicate
5752 whether we relied on an overflow infinity in the comparison. */
5756 compare_names (enum tree_code comp, tree n1, tree n2,
5757 bool *strict_overflow_p)
5761 bitmap_iterator bi1, bi2;
5763 int used_strict_overflow;
5764 static bitmap_obstack *s_obstack = NULL;
5765 static bitmap s_e1 = NULL, s_e2 = NULL;
5767 /* Compare the ranges of every name equivalent to N1 against the
5768 ranges of every name equivalent to N2. */
5769 e1 = get_value_range (n1)->equiv;
5770 e2 = get_value_range (n2)->equiv;
5772 /* Use the fake bitmaps if e1 or e2 are not available. */
5773 if (s_obstack == NULL)
5775 s_obstack = XNEW (bitmap_obstack);
5776 bitmap_obstack_initialize (s_obstack);
5777 s_e1 = BITMAP_ALLOC (s_obstack);
5778 s_e2 = BITMAP_ALLOC (s_obstack);
5785 /* Add N1 and N2 to their own set of equivalences to avoid
5786 duplicating the body of the loop just to check N1 and N2
5788 bitmap_set_bit (e1, SSA_NAME_VERSION (n1));
5789 bitmap_set_bit (e2, SSA_NAME_VERSION (n2));
5791 /* If the equivalence sets have a common intersection, then the two
5792 names can be compared without checking their ranges. */
5793 if (bitmap_intersect_p (e1, e2))
5795 bitmap_clear_bit (e1, SSA_NAME_VERSION (n1));
5796 bitmap_clear_bit (e2, SSA_NAME_VERSION (n2));
5798 return (comp == EQ_EXPR || comp == GE_EXPR || comp == LE_EXPR)
5800 : boolean_false_node;
5803 /* Start at -1. Set it to 0 if we do a comparison without relying
5804 on overflow, or 1 if all comparisons rely on overflow. */
5805 used_strict_overflow = -1;
5807 /* Otherwise, compare all the equivalent ranges. First, add N1 and
5808 N2 to their own set of equivalences to avoid duplicating the body
5809 of the loop just to check N1 and N2 ranges. */
5810 EXECUTE_IF_SET_IN_BITMAP (e1, 0, i1, bi1)
5812 value_range_t vr1 = get_vr_for_comparison (i1);
5814 t = retval = NULL_TREE;
5815 EXECUTE_IF_SET_IN_BITMAP (e2, 0, i2, bi2)
5819 value_range_t vr2 = get_vr_for_comparison (i2);
5821 t = compare_ranges (comp, &vr1, &vr2, &sop);
5824 /* If we get different answers from different members
5825 of the equivalence set this check must be in a dead
5826 code region. Folding it to a trap representation
5827 would be correct here. For now just return don't-know. */
5831 bitmap_clear_bit (e1, SSA_NAME_VERSION (n1));
5832 bitmap_clear_bit (e2, SSA_NAME_VERSION (n2));
5838 used_strict_overflow = 0;
5839 else if (used_strict_overflow < 0)
5840 used_strict_overflow = 1;
5846 bitmap_clear_bit (e1, SSA_NAME_VERSION (n1));
5847 bitmap_clear_bit (e2, SSA_NAME_VERSION (n2));
5848 if (used_strict_overflow > 0)
5849 *strict_overflow_p = true;
5854 /* None of the equivalent ranges are useful in computing this
5856 bitmap_clear_bit (e1, SSA_NAME_VERSION (n1));
5857 bitmap_clear_bit (e2, SSA_NAME_VERSION (n2));
5861 /* Helper function for vrp_evaluate_conditional_warnv. */
5864 vrp_evaluate_conditional_warnv_with_ops_using_ranges (enum tree_code code,
5866 bool * strict_overflow_p)
5868 value_range_t *vr0, *vr1;
5870 vr0 = (TREE_CODE (op0) == SSA_NAME) ? get_value_range (op0) : NULL;
5871 vr1 = (TREE_CODE (op1) == SSA_NAME) ? get_value_range (op1) : NULL;
5874 return compare_ranges (code, vr0, vr1, strict_overflow_p);
5875 else if (vr0 && vr1 == NULL)
5876 return compare_range_with_value (code, vr0, op1, strict_overflow_p);
5877 else if (vr0 == NULL && vr1)
5878 return (compare_range_with_value
5879 (swap_tree_comparison (code), vr1, op0, strict_overflow_p));
5883 /* Helper function for vrp_evaluate_conditional_warnv. */
5886 vrp_evaluate_conditional_warnv_with_ops (enum tree_code code, tree op0,
5887 tree op1, bool use_equiv_p,
5888 bool *strict_overflow_p, bool *only_ranges)
5892 *only_ranges = true;
5894 /* We only deal with integral and pointer types. */
5895 if (!INTEGRAL_TYPE_P (TREE_TYPE (op0))
5896 && !POINTER_TYPE_P (TREE_TYPE (op0)))
5902 && (ret = vrp_evaluate_conditional_warnv_with_ops_using_ranges
5903 (code, op0, op1, strict_overflow_p)))
5905 *only_ranges = false;
5906 if (TREE_CODE (op0) == SSA_NAME && TREE_CODE (op1) == SSA_NAME)
5907 return compare_names (code, op0, op1, strict_overflow_p);
5908 else if (TREE_CODE (op0) == SSA_NAME)
5909 return compare_name_with_value (code, op0, op1, strict_overflow_p);
5910 else if (TREE_CODE (op1) == SSA_NAME)
5911 return (compare_name_with_value
5912 (swap_tree_comparison (code), op1, op0, strict_overflow_p));
5915 return vrp_evaluate_conditional_warnv_with_ops_using_ranges (code, op0, op1,
5920 /* Given (CODE OP0 OP1) within STMT, try to simplify it based on value range
5921 information. Return NULL if the conditional can not be evaluated.
5922 The ranges of all the names equivalent with the operands in COND
5923 will be used when trying to compute the value. If the result is
5924 based on undefined signed overflow, issue a warning if
5928 vrp_evaluate_conditional (enum tree_code code, tree op0, tree op1, gimple stmt)
5934 /* Some passes and foldings leak constants with overflow flag set
5935 into the IL. Avoid doing wrong things with these and bail out. */
5936 if ((TREE_CODE (op0) == INTEGER_CST
5937 && TREE_OVERFLOW (op0))
5938 || (TREE_CODE (op1) == INTEGER_CST
5939 && TREE_OVERFLOW (op1)))
5943 ret = vrp_evaluate_conditional_warnv_with_ops (code, op0, op1, true, &sop,
5948 enum warn_strict_overflow_code wc;
5949 const char* warnmsg;
5951 if (is_gimple_min_invariant (ret))
5953 wc = WARN_STRICT_OVERFLOW_CONDITIONAL;
5954 warnmsg = G_("assuming signed overflow does not occur when "
5955 "simplifying conditional to constant");
5959 wc = WARN_STRICT_OVERFLOW_COMPARISON;
5960 warnmsg = G_("assuming signed overflow does not occur when "
5961 "simplifying conditional");
5964 if (issue_strict_overflow_warning (wc))
5966 location_t location;
5968 if (!gimple_has_location (stmt))
5969 location = input_location;
5971 location = gimple_location (stmt);
5972 warning_at (location, OPT_Wstrict_overflow, "%s", warnmsg);
5976 if (warn_type_limits
5977 && ret && only_ranges
5978 && TREE_CODE_CLASS (code) == tcc_comparison
5979 && TREE_CODE (op0) == SSA_NAME)
5981 /* If the comparison is being folded and the operand on the LHS
5982 is being compared against a constant value that is outside of
5983 the natural range of OP0's type, then the predicate will
5984 always fold regardless of the value of OP0. If -Wtype-limits
5985 was specified, emit a warning. */
5986 tree type = TREE_TYPE (op0);
5987 value_range_t *vr0 = get_value_range (op0);
5989 if (vr0->type != VR_VARYING
5990 && INTEGRAL_TYPE_P (type)
5991 && vrp_val_is_min (vr0->min)
5992 && vrp_val_is_max (vr0->max)
5993 && is_gimple_min_invariant (op1))
5995 location_t location;
5997 if (!gimple_has_location (stmt))
5998 location = input_location;
6000 location = gimple_location (stmt);
6002 warning_at (location, OPT_Wtype_limits,
6004 ? G_("comparison always false "
6005 "due to limited range of data type")
6006 : G_("comparison always true "
6007 "due to limited range of data type"));
6015 /* Visit conditional statement STMT. If we can determine which edge
6016 will be taken out of STMT's basic block, record it in
6017 *TAKEN_EDGE_P and return SSA_PROP_INTERESTING. Otherwise, return
6018 SSA_PROP_VARYING. */
6020 static enum ssa_prop_result
6021 vrp_visit_cond_stmt (gimple stmt, edge *taken_edge_p)
6026 *taken_edge_p = NULL;
6028 if (dump_file && (dump_flags & TDF_DETAILS))
6033 fprintf (dump_file, "\nVisiting conditional with predicate: ");
6034 print_gimple_stmt (dump_file, stmt, 0, 0);
6035 fprintf (dump_file, "\nWith known ranges\n");
6037 FOR_EACH_SSA_TREE_OPERAND (use, stmt, i, SSA_OP_USE)
6039 fprintf (dump_file, "\t");
6040 print_generic_expr (dump_file, use, 0);
6041 fprintf (dump_file, ": ");
6042 dump_value_range (dump_file, vr_value[SSA_NAME_VERSION (use)]);
6045 fprintf (dump_file, "\n");
6048 /* Compute the value of the predicate COND by checking the known
6049 ranges of each of its operands.
6051 Note that we cannot evaluate all the equivalent ranges here
6052 because those ranges may not yet be final and with the current
6053 propagation strategy, we cannot determine when the value ranges
6054 of the names in the equivalence set have changed.
6056 For instance, given the following code fragment
6060 i_14 = ASSERT_EXPR <i_5, i_5 != 0>
6064 Assume that on the first visit to i_14, i_5 has the temporary
6065 range [8, 8] because the second argument to the PHI function is
6066 not yet executable. We derive the range ~[0, 0] for i_14 and the
6067 equivalence set { i_5 }. So, when we visit 'if (i_14 == 1)' for
6068 the first time, since i_14 is equivalent to the range [8, 8], we
6069 determine that the predicate is always false.
6071 On the next round of propagation, i_13 is determined to be
6072 VARYING, which causes i_5 to drop down to VARYING. So, another
6073 visit to i_14 is scheduled. In this second visit, we compute the
6074 exact same range and equivalence set for i_14, namely ~[0, 0] and
6075 { i_5 }. But we did not have the previous range for i_5
6076 registered, so vrp_visit_assignment thinks that the range for
6077 i_14 has not changed. Therefore, the predicate 'if (i_14 == 1)'
6078 is not visited again, which stops propagation from visiting
6079 statements in the THEN clause of that if().
6081 To properly fix this we would need to keep the previous range
6082 value for the names in the equivalence set. This way we would've
6083 discovered that from one visit to the other i_5 changed from
6084 range [8, 8] to VR_VARYING.
6086 However, fixing this apparent limitation may not be worth the
6087 additional checking. Testing on several code bases (GCC, DLV,
6088 MICO, TRAMP3D and SPEC2000) showed that doing this results in
6089 4 more predicates folded in SPEC. */
6092 val = vrp_evaluate_conditional_warnv_with_ops (gimple_cond_code (stmt),
6093 gimple_cond_lhs (stmt),
6094 gimple_cond_rhs (stmt),
6099 *taken_edge_p = find_taken_edge (gimple_bb (stmt), val);
6102 if (dump_file && (dump_flags & TDF_DETAILS))
6104 "\nIgnoring predicate evaluation because "
6105 "it assumes that signed overflow is undefined");
6110 if (dump_file && (dump_flags & TDF_DETAILS))
6112 fprintf (dump_file, "\nPredicate evaluates to: ");
6113 if (val == NULL_TREE)
6114 fprintf (dump_file, "DON'T KNOW\n");
6116 print_generic_stmt (dump_file, val, 0);
6119 return (*taken_edge_p) ? SSA_PROP_INTERESTING : SSA_PROP_VARYING;
6122 /* Searches the case label vector VEC for the index *IDX of the CASE_LABEL
6123 that includes the value VAL. The search is restricted to the range
6124 [START_IDX, n - 1] where n is the size of VEC.
6126 If there is a CASE_LABEL for VAL, its index is placed in IDX and true is
6129 If there is no CASE_LABEL for VAL and there is one that is larger than VAL,
6130 it is placed in IDX and false is returned.
6132 If VAL is larger than any CASE_LABEL, n is placed on IDX and false is
6136 find_case_label_index (gimple stmt, size_t start_idx, tree val, size_t *idx)
6138 size_t n = gimple_switch_num_labels (stmt);
6141 /* Find case label for minimum of the value range or the next one.
6142 At each iteration we are searching in [low, high - 1]. */
6144 for (low = start_idx, high = n; high != low; )
6148 /* Note that i != high, so we never ask for n. */
6149 size_t i = (high + low) / 2;
6150 t = gimple_switch_label (stmt, i);
6152 /* Cache the result of comparing CASE_LOW and val. */
6153 cmp = tree_int_cst_compare (CASE_LOW (t), val);
6157 /* Ranges cannot be empty. */
6166 if (CASE_HIGH (t) != NULL
6167 && tree_int_cst_compare (CASE_HIGH (t), val) >= 0)
6179 /* Searches the case label vector VEC for the range of CASE_LABELs that is used
6180 for values between MIN and MAX. The first index is placed in MIN_IDX. The
6181 last index is placed in MAX_IDX. If the range of CASE_LABELs is empty
6182 then MAX_IDX < MIN_IDX.
6183 Returns true if the default label is not needed. */
6186 find_case_label_range (gimple stmt, tree min, tree max, size_t *min_idx,
6190 bool min_take_default = !find_case_label_index (stmt, 1, min, &i);
6191 bool max_take_default = !find_case_label_index (stmt, i, max, &j);
6195 && max_take_default)
6197 /* Only the default case label reached.
6198 Return an empty range. */
6205 bool take_default = min_take_default || max_take_default;
6209 if (max_take_default)
6212 /* If the case label range is continuous, we do not need
6213 the default case label. Verify that. */
6214 high = CASE_LOW (gimple_switch_label (stmt, i));
6215 if (CASE_HIGH (gimple_switch_label (stmt, i)))
6216 high = CASE_HIGH (gimple_switch_label (stmt, i));
6217 for (k = i + 1; k <= j; ++k)
6219 low = CASE_LOW (gimple_switch_label (stmt, k));
6220 if (!integer_onep (int_const_binop (MINUS_EXPR, low, high, 0)))
6222 take_default = true;
6226 if (CASE_HIGH (gimple_switch_label (stmt, k)))
6227 high = CASE_HIGH (gimple_switch_label (stmt, k));
6232 return !take_default;
6236 /* Visit switch statement STMT. If we can determine which edge
6237 will be taken out of STMT's basic block, record it in
6238 *TAKEN_EDGE_P and return SSA_PROP_INTERESTING. Otherwise, return
6239 SSA_PROP_VARYING. */
6241 static enum ssa_prop_result
6242 vrp_visit_switch_stmt (gimple stmt, edge *taken_edge_p)
6246 size_t i = 0, j = 0;
6249 *taken_edge_p = NULL;
6250 op = gimple_switch_index (stmt);
6251 if (TREE_CODE (op) != SSA_NAME)
6252 return SSA_PROP_VARYING;
6254 vr = get_value_range (op);
6255 if (dump_file && (dump_flags & TDF_DETAILS))
6257 fprintf (dump_file, "\nVisiting switch expression with operand ");
6258 print_generic_expr (dump_file, op, 0);
6259 fprintf (dump_file, " with known range ");
6260 dump_value_range (dump_file, vr);
6261 fprintf (dump_file, "\n");
6264 if (vr->type != VR_RANGE
6265 || symbolic_range_p (vr))
6266 return SSA_PROP_VARYING;
6268 /* Find the single edge that is taken from the switch expression. */
6269 take_default = !find_case_label_range (stmt, vr->min, vr->max, &i, &j);
6271 /* Check if the range spans no CASE_LABEL. If so, we only reach the default
6275 gcc_assert (take_default);
6276 val = gimple_switch_default_label (stmt);
6280 /* Check if labels with index i to j and maybe the default label
6281 are all reaching the same label. */
6283 val = gimple_switch_label (stmt, i);
6285 && CASE_LABEL (gimple_switch_default_label (stmt))
6286 != CASE_LABEL (val))
6288 if (dump_file && (dump_flags & TDF_DETAILS))
6289 fprintf (dump_file, " not a single destination for this "
6291 return SSA_PROP_VARYING;
6293 for (++i; i <= j; ++i)
6295 if (CASE_LABEL (gimple_switch_label (stmt, i)) != CASE_LABEL (val))
6297 if (dump_file && (dump_flags & TDF_DETAILS))
6298 fprintf (dump_file, " not a single destination for this "
6300 return SSA_PROP_VARYING;
6305 *taken_edge_p = find_edge (gimple_bb (stmt),
6306 label_to_block (CASE_LABEL (val)));
6308 if (dump_file && (dump_flags & TDF_DETAILS))
6310 fprintf (dump_file, " will take edge to ");
6311 print_generic_stmt (dump_file, CASE_LABEL (val), 0);
6314 return SSA_PROP_INTERESTING;
6318 /* Evaluate statement STMT. If the statement produces a useful range,
6319 return SSA_PROP_INTERESTING and record the SSA name with the
6320 interesting range into *OUTPUT_P.
6322 If STMT is a conditional branch and we can determine its truth
6323 value, the taken edge is recorded in *TAKEN_EDGE_P.
6325 If STMT produces a varying value, return SSA_PROP_VARYING. */
6327 static enum ssa_prop_result
6328 vrp_visit_stmt (gimple stmt, edge *taken_edge_p, tree *output_p)
6333 if (dump_file && (dump_flags & TDF_DETAILS))
6335 fprintf (dump_file, "\nVisiting statement:\n");
6336 print_gimple_stmt (dump_file, stmt, 0, dump_flags);
6337 fprintf (dump_file, "\n");
6340 if (!stmt_interesting_for_vrp (stmt))
6341 gcc_assert (stmt_ends_bb_p (stmt));
6342 else if (is_gimple_assign (stmt) || is_gimple_call (stmt))
6344 /* In general, assignments with virtual operands are not useful
6345 for deriving ranges, with the obvious exception of calls to
6346 builtin functions. */
6348 if ((is_gimple_call (stmt)
6349 && gimple_call_fndecl (stmt) != NULL_TREE
6350 && DECL_IS_BUILTIN (gimple_call_fndecl (stmt)))
6351 || !gimple_vuse (stmt))
6352 return vrp_visit_assignment_or_call (stmt, output_p);
6354 else if (gimple_code (stmt) == GIMPLE_COND)
6355 return vrp_visit_cond_stmt (stmt, taken_edge_p);
6356 else if (gimple_code (stmt) == GIMPLE_SWITCH)
6357 return vrp_visit_switch_stmt (stmt, taken_edge_p);
6359 /* All other statements produce nothing of interest for VRP, so mark
6360 their outputs varying and prevent further simulation. */
6361 FOR_EACH_SSA_TREE_OPERAND (def, stmt, iter, SSA_OP_DEF)
6362 set_value_range_to_varying (get_value_range (def));
6364 return SSA_PROP_VARYING;
6368 /* Meet operation for value ranges. Given two value ranges VR0 and
6369 VR1, store in VR0 a range that contains both VR0 and VR1. This
6370 may not be the smallest possible such range. */
6373 vrp_meet (value_range_t *vr0, value_range_t *vr1)
6375 if (vr0->type == VR_UNDEFINED)
6377 copy_value_range (vr0, vr1);
6381 if (vr1->type == VR_UNDEFINED)
6383 /* Nothing to do. VR0 already has the resulting range. */
6387 if (vr0->type == VR_VARYING)
6389 /* Nothing to do. VR0 already has the resulting range. */
6393 if (vr1->type == VR_VARYING)
6395 set_value_range_to_varying (vr0);
6399 if (vr0->type == VR_RANGE && vr1->type == VR_RANGE)
6404 /* Compute the convex hull of the ranges. The lower limit of
6405 the new range is the minimum of the two ranges. If they
6406 cannot be compared, then give up. */
6407 cmp = compare_values (vr0->min, vr1->min);
6408 if (cmp == 0 || cmp == 1)
6415 /* Similarly, the upper limit of the new range is the maximum
6416 of the two ranges. If they cannot be compared, then
6418 cmp = compare_values (vr0->max, vr1->max);
6419 if (cmp == 0 || cmp == -1)
6426 /* Check for useless ranges. */
6427 if (INTEGRAL_TYPE_P (TREE_TYPE (min))
6428 && ((vrp_val_is_min (min) || is_overflow_infinity (min))
6429 && (vrp_val_is_max (max) || is_overflow_infinity (max))))
6432 /* The resulting set of equivalences is the intersection of
6434 if (vr0->equiv && vr1->equiv && vr0->equiv != vr1->equiv)
6435 bitmap_and_into (vr0->equiv, vr1->equiv);
6436 else if (vr0->equiv && !vr1->equiv)
6437 bitmap_clear (vr0->equiv);
6439 set_value_range (vr0, vr0->type, min, max, vr0->equiv);
6441 else if (vr0->type == VR_ANTI_RANGE && vr1->type == VR_ANTI_RANGE)
6443 /* Two anti-ranges meet only if their complements intersect.
6444 Only handle the case of identical ranges. */
6445 if (compare_values (vr0->min, vr1->min) == 0
6446 && compare_values (vr0->max, vr1->max) == 0
6447 && compare_values (vr0->min, vr0->max) == 0)
6449 /* The resulting set of equivalences is the intersection of
6451 if (vr0->equiv && vr1->equiv && vr0->equiv != vr1->equiv)
6452 bitmap_and_into (vr0->equiv, vr1->equiv);
6453 else if (vr0->equiv && !vr1->equiv)
6454 bitmap_clear (vr0->equiv);
6459 else if (vr0->type == VR_ANTI_RANGE || vr1->type == VR_ANTI_RANGE)
6461 /* For a numeric range [VAL1, VAL2] and an anti-range ~[VAL3, VAL4],
6462 only handle the case where the ranges have an empty intersection.
6463 The result of the meet operation is the anti-range. */
6464 if (!symbolic_range_p (vr0)
6465 && !symbolic_range_p (vr1)
6466 && !value_ranges_intersect_p (vr0, vr1))
6468 /* Copy most of VR1 into VR0. Don't copy VR1's equivalence
6469 set. We need to compute the intersection of the two
6470 equivalence sets. */
6471 if (vr1->type == VR_ANTI_RANGE)
6472 set_value_range (vr0, vr1->type, vr1->min, vr1->max, vr0->equiv);
6474 /* The resulting set of equivalences is the intersection of
6476 if (vr0->equiv && vr1->equiv && vr0->equiv != vr1->equiv)
6477 bitmap_and_into (vr0->equiv, vr1->equiv);
6478 else if (vr0->equiv && !vr1->equiv)
6479 bitmap_clear (vr0->equiv);
6490 /* Failed to find an efficient meet. Before giving up and setting
6491 the result to VARYING, see if we can at least derive a useful
6492 anti-range. FIXME, all this nonsense about distinguishing
6493 anti-ranges from ranges is necessary because of the odd
6494 semantics of range_includes_zero_p and friends. */
6495 if (!symbolic_range_p (vr0)
6496 && ((vr0->type == VR_RANGE && !range_includes_zero_p (vr0))
6497 || (vr0->type == VR_ANTI_RANGE && range_includes_zero_p (vr0)))
6498 && !symbolic_range_p (vr1)
6499 && ((vr1->type == VR_RANGE && !range_includes_zero_p (vr1))
6500 || (vr1->type == VR_ANTI_RANGE && range_includes_zero_p (vr1))))
6502 set_value_range_to_nonnull (vr0, TREE_TYPE (vr0->min));
6504 /* Since this meet operation did not result from the meeting of
6505 two equivalent names, VR0 cannot have any equivalences. */
6507 bitmap_clear (vr0->equiv);
6510 set_value_range_to_varying (vr0);
6514 /* Visit all arguments for PHI node PHI that flow through executable
6515 edges. If a valid value range can be derived from all the incoming
6516 value ranges, set a new range for the LHS of PHI. */
6518 static enum ssa_prop_result
6519 vrp_visit_phi_node (gimple phi)
6522 tree lhs = PHI_RESULT (phi);
6523 value_range_t *lhs_vr = get_value_range (lhs);
6524 value_range_t vr_result = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
6525 int edges, old_edges;
6528 if (dump_file && (dump_flags & TDF_DETAILS))
6530 fprintf (dump_file, "\nVisiting PHI node: ");
6531 print_gimple_stmt (dump_file, phi, 0, dump_flags);
6535 for (i = 0; i < gimple_phi_num_args (phi); i++)
6537 edge e = gimple_phi_arg_edge (phi, i);
6539 if (dump_file && (dump_flags & TDF_DETAILS))
6542 "\n Argument #%d (%d -> %d %sexecutable)\n",
6543 (int) i, e->src->index, e->dest->index,
6544 (e->flags & EDGE_EXECUTABLE) ? "" : "not ");
6547 if (e->flags & EDGE_EXECUTABLE)
6549 tree arg = PHI_ARG_DEF (phi, i);
6550 value_range_t vr_arg;
6554 if (TREE_CODE (arg) == SSA_NAME)
6556 vr_arg = *(get_value_range (arg));
6560 if (is_overflow_infinity (arg))
6562 arg = copy_node (arg);
6563 TREE_OVERFLOW (arg) = 0;
6566 vr_arg.type = VR_RANGE;
6569 vr_arg.equiv = NULL;
6572 if (dump_file && (dump_flags & TDF_DETAILS))
6574 fprintf (dump_file, "\t");
6575 print_generic_expr (dump_file, arg, dump_flags);
6576 fprintf (dump_file, "\n\tValue: ");
6577 dump_value_range (dump_file, &vr_arg);
6578 fprintf (dump_file, "\n");
6581 vrp_meet (&vr_result, &vr_arg);
6583 if (vr_result.type == VR_VARYING)
6588 if (vr_result.type == VR_VARYING)
6591 old_edges = vr_phi_edge_counts[SSA_NAME_VERSION (lhs)];
6592 vr_phi_edge_counts[SSA_NAME_VERSION (lhs)] = edges;
6594 /* To prevent infinite iterations in the algorithm, derive ranges
6595 when the new value is slightly bigger or smaller than the
6596 previous one. We don't do this if we have seen a new executable
6597 edge; this helps us avoid an overflow infinity for conditionals
6598 which are not in a loop. */
6600 && edges == old_edges)
6602 int cmp_min = compare_values (lhs_vr->min, vr_result.min);
6603 int cmp_max = compare_values (lhs_vr->max, vr_result.max);
6605 /* For non VR_RANGE or for pointers fall back to varying if
6606 the range changed. */
6607 if ((lhs_vr->type != VR_RANGE || vr_result.type != VR_RANGE
6608 || POINTER_TYPE_P (TREE_TYPE (lhs)))
6609 && (cmp_min != 0 || cmp_max != 0))
6612 /* If the new minimum is smaller or larger than the previous
6613 one, go all the way to -INF. In the first case, to avoid
6614 iterating millions of times to reach -INF, and in the
6615 other case to avoid infinite bouncing between different
6617 if (cmp_min > 0 || cmp_min < 0)
6619 if (!needs_overflow_infinity (TREE_TYPE (vr_result.min))
6620 || !vrp_var_may_overflow (lhs, phi))
6621 vr_result.min = TYPE_MIN_VALUE (TREE_TYPE (vr_result.min));
6622 else if (supports_overflow_infinity (TREE_TYPE (vr_result.min)))
6624 negative_overflow_infinity (TREE_TYPE (vr_result.min));
6627 /* Similarly, if the new maximum is smaller or larger than
6628 the previous one, go all the way to +INF. */
6629 if (cmp_max < 0 || cmp_max > 0)
6631 if (!needs_overflow_infinity (TREE_TYPE (vr_result.max))
6632 || !vrp_var_may_overflow (lhs, phi))
6633 vr_result.max = TYPE_MAX_VALUE (TREE_TYPE (vr_result.max));
6634 else if (supports_overflow_infinity (TREE_TYPE (vr_result.max)))
6636 positive_overflow_infinity (TREE_TYPE (vr_result.max));
6639 /* If we dropped either bound to +-INF then if this is a loop
6640 PHI node SCEV may known more about its value-range. */
6641 if ((cmp_min > 0 || cmp_min < 0
6642 || cmp_max < 0 || cmp_max > 0)
6644 && (l = loop_containing_stmt (phi))
6645 && l->header == gimple_bb (phi))
6646 adjust_range_with_scev (&vr_result, l, phi, lhs);
6648 /* If we will end up with a (-INF, +INF) range, set it to
6649 VARYING. Same if the previous max value was invalid for
6650 the type and we end up with vr_result.min > vr_result.max. */
6651 if ((vrp_val_is_max (vr_result.max)
6652 && vrp_val_is_min (vr_result.min))
6653 || compare_values (vr_result.min,
6658 /* If the new range is different than the previous value, keep
6660 if (update_value_range (lhs, &vr_result))
6662 if (dump_file && (dump_flags & TDF_DETAILS))
6664 fprintf (dump_file, "Found new range for ");
6665 print_generic_expr (dump_file, lhs, 0);
6666 fprintf (dump_file, ": ");
6667 dump_value_range (dump_file, &vr_result);
6668 fprintf (dump_file, "\n\n");
6671 return SSA_PROP_INTERESTING;
6674 /* Nothing changed, don't add outgoing edges. */
6675 return SSA_PROP_NOT_INTERESTING;
6677 /* No match found. Set the LHS to VARYING. */
6679 set_value_range_to_varying (lhs_vr);
6680 return SSA_PROP_VARYING;
6683 /* Simplify boolean operations if the source is known
6684 to be already a boolean. */
6686 simplify_truth_ops_using_ranges (gimple_stmt_iterator *gsi, gimple stmt)
6688 enum tree_code rhs_code = gimple_assign_rhs_code (stmt);
6693 bool need_conversion;
6695 op0 = gimple_assign_rhs1 (stmt);
6696 if (TYPE_PRECISION (TREE_TYPE (op0)) != 1)
6698 if (TREE_CODE (op0) != SSA_NAME)
6700 vr = get_value_range (op0);
6702 val = compare_range_with_value (GE_EXPR, vr, integer_zero_node, &sop);
6703 if (!val || !integer_onep (val))
6706 val = compare_range_with_value (LE_EXPR, vr, integer_one_node, &sop);
6707 if (!val || !integer_onep (val))
6711 if (rhs_code == TRUTH_NOT_EXPR)
6714 op1 = build_int_cst (TREE_TYPE (op0), 1);
6718 op1 = gimple_assign_rhs2 (stmt);
6720 /* Reduce number of cases to handle. */
6721 if (is_gimple_min_invariant (op1))
6723 /* Exclude anything that should have been already folded. */
6724 if (rhs_code != EQ_EXPR
6725 && rhs_code != NE_EXPR
6726 && rhs_code != TRUTH_XOR_EXPR)
6729 if (!integer_zerop (op1)
6730 && !integer_onep (op1)
6731 && !integer_all_onesp (op1))
6734 /* Limit the number of cases we have to consider. */
6735 if (rhs_code == EQ_EXPR)
6738 op1 = fold_unary (TRUTH_NOT_EXPR, TREE_TYPE (op1), op1);
6743 /* Punt on A == B as there is no BIT_XNOR_EXPR. */
6744 if (rhs_code == EQ_EXPR)
6747 if (TYPE_PRECISION (TREE_TYPE (op1)) != 1)
6749 vr = get_value_range (op1);
6750 val = compare_range_with_value (GE_EXPR, vr, integer_zero_node, &sop);
6751 if (!val || !integer_onep (val))
6754 val = compare_range_with_value (LE_EXPR, vr, integer_one_node, &sop);
6755 if (!val || !integer_onep (val))
6761 if (sop && issue_strict_overflow_warning (WARN_STRICT_OVERFLOW_MISC))
6763 location_t location;
6765 if (!gimple_has_location (stmt))
6766 location = input_location;
6768 location = gimple_location (stmt);
6770 if (rhs_code == TRUTH_AND_EXPR || rhs_code == TRUTH_OR_EXPR)
6771 warning_at (location, OPT_Wstrict_overflow,
6772 _("assuming signed overflow does not occur when "
6773 "simplifying && or || to & or |"));
6775 warning_at (location, OPT_Wstrict_overflow,
6776 _("assuming signed overflow does not occur when "
6777 "simplifying ==, != or ! to identity or ^"));
6781 !useless_type_conversion_p (TREE_TYPE (gimple_assign_lhs (stmt)),
6784 /* Make sure to not sign-extend -1 as a boolean value. */
6786 && !TYPE_UNSIGNED (TREE_TYPE (op0))
6787 && TYPE_PRECISION (TREE_TYPE (op0)) == 1)
6792 case TRUTH_AND_EXPR:
6793 rhs_code = BIT_AND_EXPR;
6796 rhs_code = BIT_IOR_EXPR;
6798 case TRUTH_XOR_EXPR:
6800 if (integer_zerop (op1))
6802 gimple_assign_set_rhs_with_ops (gsi,
6803 need_conversion ? NOP_EXPR : SSA_NAME,
6805 update_stmt (gsi_stmt (*gsi));
6809 rhs_code = BIT_XOR_EXPR;
6815 if (need_conversion)
6818 gimple_assign_set_rhs_with_ops (gsi, rhs_code, op0, op1);
6819 update_stmt (gsi_stmt (*gsi));
6823 /* Simplify a division or modulo operator to a right shift or
6824 bitwise and if the first operand is unsigned or is greater
6825 than zero and the second operand is an exact power of two. */
6828 simplify_div_or_mod_using_ranges (gimple stmt)
6830 enum tree_code rhs_code = gimple_assign_rhs_code (stmt);
6832 tree op0 = gimple_assign_rhs1 (stmt);
6833 tree op1 = gimple_assign_rhs2 (stmt);
6834 value_range_t *vr = get_value_range (gimple_assign_rhs1 (stmt));
6836 if (TYPE_UNSIGNED (TREE_TYPE (op0)))
6838 val = integer_one_node;
6844 val = compare_range_with_value (GE_EXPR, vr, integer_zero_node, &sop);
6848 && integer_onep (val)
6849 && issue_strict_overflow_warning (WARN_STRICT_OVERFLOW_MISC))
6851 location_t location;
6853 if (!gimple_has_location (stmt))
6854 location = input_location;
6856 location = gimple_location (stmt);
6857 warning_at (location, OPT_Wstrict_overflow,
6858 "assuming signed overflow does not occur when "
6859 "simplifying %</%> or %<%%%> to %<>>%> or %<&%>");
6863 if (val && integer_onep (val))
6867 if (rhs_code == TRUNC_DIV_EXPR)
6869 t = build_int_cst (NULL_TREE, tree_log2 (op1));
6870 gimple_assign_set_rhs_code (stmt, RSHIFT_EXPR);
6871 gimple_assign_set_rhs1 (stmt, op0);
6872 gimple_assign_set_rhs2 (stmt, t);
6876 t = build_int_cst (TREE_TYPE (op1), 1);
6877 t = int_const_binop (MINUS_EXPR, op1, t, 0);
6878 t = fold_convert (TREE_TYPE (op0), t);
6880 gimple_assign_set_rhs_code (stmt, BIT_AND_EXPR);
6881 gimple_assign_set_rhs1 (stmt, op0);
6882 gimple_assign_set_rhs2 (stmt, t);
6892 /* If the operand to an ABS_EXPR is >= 0, then eliminate the
6893 ABS_EXPR. If the operand is <= 0, then simplify the
6894 ABS_EXPR into a NEGATE_EXPR. */
6897 simplify_abs_using_ranges (gimple stmt)
6900 tree op = gimple_assign_rhs1 (stmt);
6901 tree type = TREE_TYPE (op);
6902 value_range_t *vr = get_value_range (op);
6904 if (TYPE_UNSIGNED (type))
6906 val = integer_zero_node;
6912 val = compare_range_with_value (LE_EXPR, vr, integer_zero_node, &sop);
6916 val = compare_range_with_value (GE_EXPR, vr, integer_zero_node,
6921 if (integer_zerop (val))
6922 val = integer_one_node;
6923 else if (integer_onep (val))
6924 val = integer_zero_node;
6929 && (integer_onep (val) || integer_zerop (val)))
6931 if (sop && issue_strict_overflow_warning (WARN_STRICT_OVERFLOW_MISC))
6933 location_t location;
6935 if (!gimple_has_location (stmt))
6936 location = input_location;
6938 location = gimple_location (stmt);
6939 warning_at (location, OPT_Wstrict_overflow,
6940 "assuming signed overflow does not occur when "
6941 "simplifying %<abs (X)%> to %<X%> or %<-X%>");
6944 gimple_assign_set_rhs1 (stmt, op);
6945 if (integer_onep (val))
6946 gimple_assign_set_rhs_code (stmt, NEGATE_EXPR);
6948 gimple_assign_set_rhs_code (stmt, SSA_NAME);
6957 /* Optimize away redundant BIT_AND_EXPR and BIT_IOR_EXPR.
6958 If all the bits that are being cleared by & are already
6959 known to be zero from VR, or all the bits that are being
6960 set by | are already known to be one from VR, the bit
6961 operation is redundant. */
6964 simplify_bit_ops_using_ranges (gimple_stmt_iterator *gsi, gimple stmt)
6966 tree op0 = gimple_assign_rhs1 (stmt);
6967 tree op1 = gimple_assign_rhs2 (stmt);
6968 tree op = NULL_TREE;
6969 value_range_t vr0 = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
6970 value_range_t vr1 = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
6971 double_int may_be_nonzero0, may_be_nonzero1;
6972 double_int must_be_nonzero0, must_be_nonzero1;
6975 if (TREE_CODE (op0) == SSA_NAME)
6976 vr0 = *(get_value_range (op0));
6977 else if (is_gimple_min_invariant (op0))
6978 set_value_range_to_value (&vr0, op0, NULL);
6982 if (TREE_CODE (op1) == SSA_NAME)
6983 vr1 = *(get_value_range (op1));
6984 else if (is_gimple_min_invariant (op1))
6985 set_value_range_to_value (&vr1, op1, NULL);
6989 if (!zero_nonzero_bits_from_vr (&vr0, &may_be_nonzero0, &must_be_nonzero0))
6991 if (!zero_nonzero_bits_from_vr (&vr1, &may_be_nonzero1, &must_be_nonzero1))
6994 switch (gimple_assign_rhs_code (stmt))
6997 mask = double_int_and_not (may_be_nonzero0, must_be_nonzero1);
6998 if (double_int_zero_p (mask))
7003 mask = double_int_and_not (may_be_nonzero1, must_be_nonzero0);
7004 if (double_int_zero_p (mask))
7011 mask = double_int_and_not (may_be_nonzero0, must_be_nonzero1);
7012 if (double_int_zero_p (mask))
7017 mask = double_int_and_not (may_be_nonzero1, must_be_nonzero0);
7018 if (double_int_zero_p (mask))
7028 if (op == NULL_TREE)
7031 gimple_assign_set_rhs_with_ops (gsi, TREE_CODE (op), op, NULL);
7032 update_stmt (gsi_stmt (*gsi));
7036 /* We are comparing trees OP0 and OP1 using COND_CODE. OP0 has
7037 a known value range VR.
7039 If there is one and only one value which will satisfy the
7040 conditional, then return that value. Else return NULL. */
7043 test_for_singularity (enum tree_code cond_code, tree op0,
7044 tree op1, value_range_t *vr)
7049 /* Extract minimum/maximum values which satisfy the
7050 the conditional as it was written. */
7051 if (cond_code == LE_EXPR || cond_code == LT_EXPR)
7053 /* This should not be negative infinity; there is no overflow
7055 min = TYPE_MIN_VALUE (TREE_TYPE (op0));
7058 if (cond_code == LT_EXPR && !is_overflow_infinity (max))
7060 tree one = build_int_cst (TREE_TYPE (op0), 1);
7061 max = fold_build2 (MINUS_EXPR, TREE_TYPE (op0), max, one);
7063 TREE_NO_WARNING (max) = 1;
7066 else if (cond_code == GE_EXPR || cond_code == GT_EXPR)
7068 /* This should not be positive infinity; there is no overflow
7070 max = TYPE_MAX_VALUE (TREE_TYPE (op0));
7073 if (cond_code == GT_EXPR && !is_overflow_infinity (min))
7075 tree one = build_int_cst (TREE_TYPE (op0), 1);
7076 min = fold_build2 (PLUS_EXPR, TREE_TYPE (op0), min, one);
7078 TREE_NO_WARNING (min) = 1;
7082 /* Now refine the minimum and maximum values using any
7083 value range information we have for op0. */
7086 if (compare_values (vr->min, min) == 1)
7088 if (compare_values (vr->max, max) == -1)
7091 /* If the new min/max values have converged to a single value,
7092 then there is only one value which can satisfy the condition,
7093 return that value. */
7094 if (operand_equal_p (min, max, 0) && is_gimple_min_invariant (min))
7100 /* Simplify a conditional using a relational operator to an equality
7101 test if the range information indicates only one value can satisfy
7102 the original conditional. */
7105 simplify_cond_using_ranges (gimple stmt)
7107 tree op0 = gimple_cond_lhs (stmt);
7108 tree op1 = gimple_cond_rhs (stmt);
7109 enum tree_code cond_code = gimple_cond_code (stmt);
7111 if (cond_code != NE_EXPR
7112 && cond_code != EQ_EXPR
7113 && TREE_CODE (op0) == SSA_NAME
7114 && INTEGRAL_TYPE_P (TREE_TYPE (op0))
7115 && is_gimple_min_invariant (op1))
7117 value_range_t *vr = get_value_range (op0);
7119 /* If we have range information for OP0, then we might be
7120 able to simplify this conditional. */
7121 if (vr->type == VR_RANGE)
7123 tree new_tree = test_for_singularity (cond_code, op0, op1, vr);
7129 fprintf (dump_file, "Simplified relational ");
7130 print_gimple_stmt (dump_file, stmt, 0, 0);
7131 fprintf (dump_file, " into ");
7134 gimple_cond_set_code (stmt, EQ_EXPR);
7135 gimple_cond_set_lhs (stmt, op0);
7136 gimple_cond_set_rhs (stmt, new_tree);
7142 print_gimple_stmt (dump_file, stmt, 0, 0);
7143 fprintf (dump_file, "\n");
7149 /* Try again after inverting the condition. We only deal
7150 with integral types here, so no need to worry about
7151 issues with inverting FP comparisons. */
7152 cond_code = invert_tree_comparison (cond_code, false);
7153 new_tree = test_for_singularity (cond_code, op0, op1, vr);
7159 fprintf (dump_file, "Simplified relational ");
7160 print_gimple_stmt (dump_file, stmt, 0, 0);
7161 fprintf (dump_file, " into ");
7164 gimple_cond_set_code (stmt, NE_EXPR);
7165 gimple_cond_set_lhs (stmt, op0);
7166 gimple_cond_set_rhs (stmt, new_tree);
7172 print_gimple_stmt (dump_file, stmt, 0, 0);
7173 fprintf (dump_file, "\n");
7184 /* Simplify a switch statement using the value range of the switch
7188 simplify_switch_using_ranges (gimple stmt)
7190 tree op = gimple_switch_index (stmt);
7195 size_t i = 0, j = 0, n, n2;
7199 if (TREE_CODE (op) == SSA_NAME)
7201 vr = get_value_range (op);
7203 /* We can only handle integer ranges. */
7204 if (vr->type != VR_RANGE
7205 || symbolic_range_p (vr))
7208 /* Find case label for min/max of the value range. */
7209 take_default = !find_case_label_range (stmt, vr->min, vr->max, &i, &j);
7211 else if (TREE_CODE (op) == INTEGER_CST)
7213 take_default = !find_case_label_index (stmt, 1, op, &i);
7227 n = gimple_switch_num_labels (stmt);
7229 /* Bail out if this is just all edges taken. */
7235 /* Build a new vector of taken case labels. */
7236 vec2 = make_tree_vec (j - i + 1 + (int)take_default);
7239 /* Add the default edge, if necessary. */
7241 TREE_VEC_ELT (vec2, n2++) = gimple_switch_default_label (stmt);
7243 for (; i <= j; ++i, ++n2)
7244 TREE_VEC_ELT (vec2, n2) = gimple_switch_label (stmt, i);
7246 /* Mark needed edges. */
7247 for (i = 0; i < n2; ++i)
7249 e = find_edge (gimple_bb (stmt),
7250 label_to_block (CASE_LABEL (TREE_VEC_ELT (vec2, i))));
7251 e->aux = (void *)-1;
7254 /* Queue not needed edges for later removal. */
7255 FOR_EACH_EDGE (e, ei, gimple_bb (stmt)->succs)
7257 if (e->aux == (void *)-1)
7263 if (dump_file && (dump_flags & TDF_DETAILS))
7265 fprintf (dump_file, "removing unreachable case label\n");
7267 VEC_safe_push (edge, heap, to_remove_edges, e);
7268 e->flags &= ~EDGE_EXECUTABLE;
7271 /* And queue an update for the stmt. */
7274 VEC_safe_push (switch_update, heap, to_update_switch_stmts, &su);
7278 /* Simplify STMT using ranges if possible. */
7281 simplify_stmt_using_ranges (gimple_stmt_iterator *gsi)
7283 gimple stmt = gsi_stmt (*gsi);
7284 if (is_gimple_assign (stmt))
7286 enum tree_code rhs_code = gimple_assign_rhs_code (stmt);
7292 case TRUTH_NOT_EXPR:
7293 case TRUTH_AND_EXPR:
7295 case TRUTH_XOR_EXPR:
7296 /* Transform EQ_EXPR, NE_EXPR, TRUTH_NOT_EXPR into BIT_XOR_EXPR
7297 or identity if the RHS is zero or one, and the LHS are known
7298 to be boolean values. Transform all TRUTH_*_EXPR into
7299 BIT_*_EXPR if both arguments are known to be boolean values. */
7300 if (INTEGRAL_TYPE_P (TREE_TYPE (gimple_assign_rhs1 (stmt))))
7301 return simplify_truth_ops_using_ranges (gsi, stmt);
7304 /* Transform TRUNC_DIV_EXPR and TRUNC_MOD_EXPR into RSHIFT_EXPR
7305 and BIT_AND_EXPR respectively if the first operand is greater
7306 than zero and the second operand is an exact power of two. */
7307 case TRUNC_DIV_EXPR:
7308 case TRUNC_MOD_EXPR:
7309 if (INTEGRAL_TYPE_P (TREE_TYPE (gimple_assign_rhs1 (stmt)))
7310 && integer_pow2p (gimple_assign_rhs2 (stmt)))
7311 return simplify_div_or_mod_using_ranges (stmt);
7314 /* Transform ABS (X) into X or -X as appropriate. */
7316 if (TREE_CODE (gimple_assign_rhs1 (stmt)) == SSA_NAME
7317 && INTEGRAL_TYPE_P (TREE_TYPE (gimple_assign_rhs1 (stmt))))
7318 return simplify_abs_using_ranges (stmt);
7323 /* Optimize away BIT_AND_EXPR and BIT_IOR_EXPR
7324 if all the bits being cleared are already cleared or
7325 all the bits being set are already set. */
7326 if (INTEGRAL_TYPE_P (TREE_TYPE (gimple_assign_rhs1 (stmt))))
7327 return simplify_bit_ops_using_ranges (gsi, stmt);
7334 else if (gimple_code (stmt) == GIMPLE_COND)
7335 return simplify_cond_using_ranges (stmt);
7336 else if (gimple_code (stmt) == GIMPLE_SWITCH)
7337 return simplify_switch_using_ranges (stmt);
7342 /* If the statement pointed by SI has a predicate whose value can be
7343 computed using the value range information computed by VRP, compute
7344 its value and return true. Otherwise, return false. */
7347 fold_predicate_in (gimple_stmt_iterator *si)
7349 bool assignment_p = false;
7351 gimple stmt = gsi_stmt (*si);
7353 if (is_gimple_assign (stmt)
7354 && TREE_CODE_CLASS (gimple_assign_rhs_code (stmt)) == tcc_comparison)
7356 assignment_p = true;
7357 val = vrp_evaluate_conditional (gimple_assign_rhs_code (stmt),
7358 gimple_assign_rhs1 (stmt),
7359 gimple_assign_rhs2 (stmt),
7362 else if (gimple_code (stmt) == GIMPLE_COND)
7363 val = vrp_evaluate_conditional (gimple_cond_code (stmt),
7364 gimple_cond_lhs (stmt),
7365 gimple_cond_rhs (stmt),
7373 val = fold_convert (gimple_expr_type (stmt), val);
7377 fprintf (dump_file, "Folding predicate ");
7378 print_gimple_expr (dump_file, stmt, 0, 0);
7379 fprintf (dump_file, " to ");
7380 print_generic_expr (dump_file, val, 0);
7381 fprintf (dump_file, "\n");
7384 if (is_gimple_assign (stmt))
7385 gimple_assign_set_rhs_from_tree (si, val);
7388 gcc_assert (gimple_code (stmt) == GIMPLE_COND);
7389 if (integer_zerop (val))
7390 gimple_cond_make_false (stmt);
7391 else if (integer_onep (val))
7392 gimple_cond_make_true (stmt);
7403 /* Callback for substitute_and_fold folding the stmt at *SI. */
7406 vrp_fold_stmt (gimple_stmt_iterator *si)
7408 if (fold_predicate_in (si))
7411 return simplify_stmt_using_ranges (si);
7414 /* Stack of dest,src equivalency pairs that need to be restored after
7415 each attempt to thread a block's incoming edge to an outgoing edge.
7417 A NULL entry is used to mark the end of pairs which need to be
7419 static VEC(tree,heap) *stack;
7421 /* A trivial wrapper so that we can present the generic jump threading
7422 code with a simple API for simplifying statements. STMT is the
7423 statement we want to simplify, WITHIN_STMT provides the location
7424 for any overflow warnings. */
7427 simplify_stmt_for_jump_threading (gimple stmt, gimple within_stmt)
7429 /* We only use VRP information to simplify conditionals. This is
7430 overly conservative, but it's unclear if doing more would be
7431 worth the compile time cost. */
7432 if (gimple_code (stmt) != GIMPLE_COND)
7435 return vrp_evaluate_conditional (gimple_cond_code (stmt),
7436 gimple_cond_lhs (stmt),
7437 gimple_cond_rhs (stmt), within_stmt);
7440 /* Blocks which have more than one predecessor and more than
7441 one successor present jump threading opportunities, i.e.,
7442 when the block is reached from a specific predecessor, we
7443 may be able to determine which of the outgoing edges will
7444 be traversed. When this optimization applies, we are able
7445 to avoid conditionals at runtime and we may expose secondary
7446 optimization opportunities.
7448 This routine is effectively a driver for the generic jump
7449 threading code. It basically just presents the generic code
7450 with edges that may be suitable for jump threading.
7452 Unlike DOM, we do not iterate VRP if jump threading was successful.
7453 While iterating may expose new opportunities for VRP, it is expected
7454 those opportunities would be very limited and the compile time cost
7455 to expose those opportunities would be significant.
7457 As jump threading opportunities are discovered, they are registered
7458 for later realization. */
7461 identify_jump_threads (void)
7468 /* Ugh. When substituting values earlier in this pass we can
7469 wipe the dominance information. So rebuild the dominator
7470 information as we need it within the jump threading code. */
7471 calculate_dominance_info (CDI_DOMINATORS);
7473 /* We do not allow VRP information to be used for jump threading
7474 across a back edge in the CFG. Otherwise it becomes too
7475 difficult to avoid eliminating loop exit tests. Of course
7476 EDGE_DFS_BACK is not accurate at this time so we have to
7478 mark_dfs_back_edges ();
7480 /* Do not thread across edges we are about to remove. Just marking
7481 them as EDGE_DFS_BACK will do. */
7482 FOR_EACH_VEC_ELT (edge, to_remove_edges, i, e)
7483 e->flags |= EDGE_DFS_BACK;
7485 /* Allocate our unwinder stack to unwind any temporary equivalences
7486 that might be recorded. */
7487 stack = VEC_alloc (tree, heap, 20);
7489 /* To avoid lots of silly node creation, we create a single
7490 conditional and just modify it in-place when attempting to
7492 dummy = gimple_build_cond (EQ_EXPR,
7493 integer_zero_node, integer_zero_node,
7496 /* Walk through all the blocks finding those which present a
7497 potential jump threading opportunity. We could set this up
7498 as a dominator walker and record data during the walk, but
7499 I doubt it's worth the effort for the classes of jump
7500 threading opportunities we are trying to identify at this
7501 point in compilation. */
7506 /* If the generic jump threading code does not find this block
7507 interesting, then there is nothing to do. */
7508 if (! potentially_threadable_block (bb))
7511 /* We only care about blocks ending in a COND_EXPR. While there
7512 may be some value in handling SWITCH_EXPR here, I doubt it's
7513 terribly important. */
7514 last = gsi_stmt (gsi_last_bb (bb));
7515 if (gimple_code (last) != GIMPLE_COND)
7518 /* We're basically looking for any kind of conditional with
7519 integral type arguments. */
7520 if (TREE_CODE (gimple_cond_lhs (last)) == SSA_NAME
7521 && INTEGRAL_TYPE_P (TREE_TYPE (gimple_cond_lhs (last)))
7522 && (TREE_CODE (gimple_cond_rhs (last)) == SSA_NAME
7523 || is_gimple_min_invariant (gimple_cond_rhs (last)))
7524 && INTEGRAL_TYPE_P (TREE_TYPE (gimple_cond_rhs (last))))
7528 /* We've got a block with multiple predecessors and multiple
7529 successors which also ends in a suitable conditional. For
7530 each predecessor, see if we can thread it to a specific
7532 FOR_EACH_EDGE (e, ei, bb->preds)
7534 /* Do not thread across back edges or abnormal edges
7536 if (e->flags & (EDGE_DFS_BACK | EDGE_COMPLEX))
7539 thread_across_edge (dummy, e, true, &stack,
7540 simplify_stmt_for_jump_threading);
7545 /* We do not actually update the CFG or SSA graphs at this point as
7546 ASSERT_EXPRs are still in the IL and cfg cleanup code does not yet
7547 handle ASSERT_EXPRs gracefully. */
7550 /* We identified all the jump threading opportunities earlier, but could
7551 not transform the CFG at that time. This routine transforms the
7552 CFG and arranges for the dominator tree to be rebuilt if necessary.
7554 Note the SSA graph update will occur during the normal TODO
7555 processing by the pass manager. */
7557 finalize_jump_threads (void)
7559 thread_through_all_blocks (false);
7560 VEC_free (tree, heap, stack);
7564 /* Traverse all the blocks folding conditionals with known ranges. */
7570 unsigned num = num_ssa_names;
7574 fprintf (dump_file, "\nValue ranges after VRP:\n\n");
7575 dump_all_value_ranges (dump_file);
7576 fprintf (dump_file, "\n");
7579 substitute_and_fold (op_with_constant_singleton_value_range,
7580 vrp_fold_stmt, false);
7582 if (warn_array_bounds)
7583 check_all_array_refs ();
7585 /* We must identify jump threading opportunities before we release
7586 the datastructures built by VRP. */
7587 identify_jump_threads ();
7589 /* Free allocated memory. */
7590 for (i = 0; i < num; i++)
7593 BITMAP_FREE (vr_value[i]->equiv);
7598 free (vr_phi_edge_counts);
7600 /* So that we can distinguish between VRP data being available
7601 and not available. */
7603 vr_phi_edge_counts = NULL;
7607 /* Main entry point to VRP (Value Range Propagation). This pass is
7608 loosely based on J. R. C. Patterson, ``Accurate Static Branch
7609 Prediction by Value Range Propagation,'' in SIGPLAN Conference on
7610 Programming Language Design and Implementation, pp. 67-78, 1995.
7611 Also available at http://citeseer.ist.psu.edu/patterson95accurate.html
7613 This is essentially an SSA-CCP pass modified to deal with ranges
7614 instead of constants.
7616 While propagating ranges, we may find that two or more SSA name
7617 have equivalent, though distinct ranges. For instance,
7620 2 p_4 = ASSERT_EXPR <p_3, p_3 != 0>
7622 4 p_5 = ASSERT_EXPR <p_4, p_4 == q_2>;
7626 In the code above, pointer p_5 has range [q_2, q_2], but from the
7627 code we can also determine that p_5 cannot be NULL and, if q_2 had
7628 a non-varying range, p_5's range should also be compatible with it.
7630 These equivalences are created by two expressions: ASSERT_EXPR and
7631 copy operations. Since p_5 is an assertion on p_4, and p_4 was the
7632 result of another assertion, then we can use the fact that p_5 and
7633 p_4 are equivalent when evaluating p_5's range.
7635 Together with value ranges, we also propagate these equivalences
7636 between names so that we can take advantage of information from
7637 multiple ranges when doing final replacement. Note that this
7638 equivalency relation is transitive but not symmetric.
7640 In the example above, p_5 is equivalent to p_4, q_2 and p_3, but we
7641 cannot assert that q_2 is equivalent to p_5 because q_2 may be used
7642 in contexts where that assertion does not hold (e.g., in line 6).
7644 TODO, the main difference between this pass and Patterson's is that
7645 we do not propagate edge probabilities. We only compute whether
7646 edges can be taken or not. That is, instead of having a spectrum
7647 of jump probabilities between 0 and 1, we only deal with 0, 1 and
7648 DON'T KNOW. In the future, it may be worthwhile to propagate
7649 probabilities to aid branch prediction. */
7658 loop_optimizer_init (LOOPS_NORMAL | LOOPS_HAVE_RECORDED_EXITS);
7659 rewrite_into_loop_closed_ssa (NULL, TODO_update_ssa);
7662 /* Estimate number of iterations - but do not use undefined behavior
7663 for this. We can't do this lazily as other functions may compute
7664 this using undefined behavior. */
7665 free_numbers_of_iterations_estimates ();
7666 estimate_numbers_of_iterations (false);
7668 insert_range_assertions ();
7670 to_remove_edges = VEC_alloc (edge, heap, 10);
7671 to_update_switch_stmts = VEC_alloc (switch_update, heap, 5);
7672 threadedge_initialize_values ();
7675 ssa_propagate (vrp_visit_stmt, vrp_visit_phi_node);
7678 /* ASSERT_EXPRs must be removed before finalizing jump threads
7679 as finalizing jump threads calls the CFG cleanup code which
7680 does not properly handle ASSERT_EXPRs. */
7681 remove_range_assertions ();
7683 /* If we exposed any new variables, go ahead and put them into
7684 SSA form now, before we handle jump threading. This simplifies
7685 interactions between rewriting of _DECL nodes into SSA form
7686 and rewriting SSA_NAME nodes into SSA form after block
7687 duplication and CFG manipulation. */
7688 update_ssa (TODO_update_ssa);
7690 finalize_jump_threads ();
7692 /* Remove dead edges from SWITCH_EXPR optimization. This leaves the
7693 CFG in a broken state and requires a cfg_cleanup run. */
7694 FOR_EACH_VEC_ELT (edge, to_remove_edges, i, e)
7696 /* Update SWITCH_EXPR case label vector. */
7697 FOR_EACH_VEC_ELT (switch_update, to_update_switch_stmts, i, su)
7700 size_t n = TREE_VEC_LENGTH (su->vec);
7702 gimple_switch_set_num_labels (su->stmt, n);
7703 for (j = 0; j < n; j++)
7704 gimple_switch_set_label (su->stmt, j, TREE_VEC_ELT (su->vec, j));
7705 /* As we may have replaced the default label with a regular one
7706 make sure to make it a real default label again. This ensures
7707 optimal expansion. */
7708 label = gimple_switch_default_label (su->stmt);
7709 CASE_LOW (label) = NULL_TREE;
7710 CASE_HIGH (label) = NULL_TREE;
7713 if (VEC_length (edge, to_remove_edges) > 0)
7714 free_dominance_info (CDI_DOMINATORS);
7716 VEC_free (edge, heap, to_remove_edges);
7717 VEC_free (switch_update, heap, to_update_switch_stmts);
7718 threadedge_finalize_values ();
7721 loop_optimizer_finalize ();
7728 return flag_tree_vrp != 0;
7731 struct gimple_opt_pass pass_vrp =
7736 gate_vrp, /* gate */
7737 execute_vrp, /* execute */
7740 0, /* static_pass_number */
7741 TV_TREE_VRP, /* tv_id */
7742 PROP_ssa, /* properties_required */
7743 0, /* properties_provided */
7744 0, /* properties_destroyed */
7745 0, /* todo_flags_start */
7750 | TODO_update_ssa /* todo_flags_finish */