1 /* Support routines for Value Range Propagation (VRP).
2 Copyright (C) 2005, 2006, 2007 Free Software Foundation, Inc.
3 Contributed by Diego Novillo <dnovillo@redhat.com>.
5 This file is part of GCC.
7 GCC is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 3, or (at your option)
12 GCC is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with GCC; see the file COPYING3. If not see
19 <http://www.gnu.org/licenses/>. */
23 #include "coretypes.h"
28 #include "basic-block.h"
29 #include "tree-flow.h"
30 #include "tree-pass.h"
31 #include "tree-dump.h"
33 #include "diagnostic.h"
37 #include "tree-scalar-evolution.h"
38 #include "tree-ssa-propagate.h"
39 #include "tree-chrec.h"
41 /* Set of SSA names found during the dominator traversal of a
42 sub-graph in find_assert_locations. */
43 static sbitmap found_in_subgraph;
45 /* Local functions. */
46 static int compare_values (tree val1, tree val2);
47 static int compare_values_warnv (tree val1, tree val2, bool *);
48 static void vrp_meet (value_range_t *, value_range_t *);
49 static tree vrp_evaluate_conditional_warnv (tree, bool, bool *);
51 /* Location information for ASSERT_EXPRs. Each instance of this
52 structure describes an ASSERT_EXPR for an SSA name. Since a single
53 SSA name may have more than one assertion associated with it, these
54 locations are kept in a linked list attached to the corresponding
58 /* Basic block where the assertion would be inserted. */
61 /* Some assertions need to be inserted on an edge (e.g., assertions
62 generated by COND_EXPRs). In those cases, BB will be NULL. */
65 /* Pointer to the statement that generated this assertion. */
66 block_stmt_iterator si;
68 /* Predicate code for the ASSERT_EXPR. Must be COMPARISON_CLASS_P. */
69 enum tree_code comp_code;
71 /* Value being compared against. */
74 /* Expression to compare. */
77 /* Next node in the linked list. */
78 struct assert_locus_d *next;
81 typedef struct assert_locus_d *assert_locus_t;
83 /* If bit I is present, it means that SSA name N_i has a list of
84 assertions that should be inserted in the IL. */
85 static bitmap need_assert_for;
87 /* Array of locations lists where to insert assertions. ASSERTS_FOR[I]
88 holds a list of ASSERT_LOCUS_T nodes that describe where
89 ASSERT_EXPRs for SSA name N_I should be inserted. */
90 static assert_locus_t *asserts_for;
92 /* Set of blocks visited in find_assert_locations. Used to avoid
93 visiting the same block more than once. */
94 static sbitmap blocks_visited;
96 /* Value range array. After propagation, VR_VALUE[I] holds the range
97 of values that SSA name N_I may take. */
98 static value_range_t **vr_value;
100 /* For a PHI node which sets SSA name N_I, VR_COUNTS[I] holds the
101 number of executable edges we saw the last time we visited the
103 static int *vr_phi_edge_counts;
106 /* Return whether TYPE should use an overflow infinity distinct from
107 TYPE_{MIN,MAX}_VALUE. We use an overflow infinity value to
108 represent a signed overflow during VRP computations. An infinity
109 is distinct from a half-range, which will go from some number to
110 TYPE_{MIN,MAX}_VALUE. */
113 needs_overflow_infinity (const_tree type)
115 return (INTEGRAL_TYPE_P (type)
116 && !TYPE_OVERFLOW_WRAPS (type)
117 /* Integer sub-types never overflow as they are never
118 operands of arithmetic operators. */
119 && !(TREE_TYPE (type) && TREE_TYPE (type) != type));
122 /* Return whether TYPE can support our overflow infinity
123 representation: we use the TREE_OVERFLOW flag, which only exists
124 for constants. If TYPE doesn't support this, we don't optimize
125 cases which would require signed overflow--we drop them to
129 supports_overflow_infinity (const_tree type)
131 #ifdef ENABLE_CHECKING
132 gcc_assert (needs_overflow_infinity (type));
134 return (TYPE_MIN_VALUE (type) != NULL_TREE
135 && CONSTANT_CLASS_P (TYPE_MIN_VALUE (type))
136 && TYPE_MAX_VALUE (type) != NULL_TREE
137 && CONSTANT_CLASS_P (TYPE_MAX_VALUE (type)));
140 /* VAL is the maximum or minimum value of a type. Return a
141 corresponding overflow infinity. */
144 make_overflow_infinity (tree val)
146 #ifdef ENABLE_CHECKING
147 gcc_assert (val != NULL_TREE && CONSTANT_CLASS_P (val));
149 val = copy_node (val);
150 TREE_OVERFLOW (val) = 1;
154 /* Return a negative overflow infinity for TYPE. */
157 negative_overflow_infinity (tree type)
159 #ifdef ENABLE_CHECKING
160 gcc_assert (supports_overflow_infinity (type));
162 return make_overflow_infinity (TYPE_MIN_VALUE (type));
165 /* Return a positive overflow infinity for TYPE. */
168 positive_overflow_infinity (tree type)
170 #ifdef ENABLE_CHECKING
171 gcc_assert (supports_overflow_infinity (type));
173 return make_overflow_infinity (TYPE_MAX_VALUE (type));
176 /* Return whether VAL is a negative overflow infinity. */
179 is_negative_overflow_infinity (const_tree val)
181 return (needs_overflow_infinity (TREE_TYPE (val))
182 && CONSTANT_CLASS_P (val)
183 && TREE_OVERFLOW (val)
184 && operand_equal_p (val, TYPE_MIN_VALUE (TREE_TYPE (val)), 0));
187 /* Return whether VAL is a positive overflow infinity. */
190 is_positive_overflow_infinity (const_tree val)
192 return (needs_overflow_infinity (TREE_TYPE (val))
193 && CONSTANT_CLASS_P (val)
194 && TREE_OVERFLOW (val)
195 && operand_equal_p (val, TYPE_MAX_VALUE (TREE_TYPE (val)), 0));
198 /* Return whether VAL is a positive or negative overflow infinity. */
201 is_overflow_infinity (const_tree val)
203 return (needs_overflow_infinity (TREE_TYPE (val))
204 && CONSTANT_CLASS_P (val)
205 && TREE_OVERFLOW (val)
206 && (operand_equal_p (val, TYPE_MAX_VALUE (TREE_TYPE (val)), 0)
207 || operand_equal_p (val, TYPE_MIN_VALUE (TREE_TYPE (val)), 0)));
210 /* If VAL is now an overflow infinity, return VAL. Otherwise, return
211 the same value with TREE_OVERFLOW clear. This can be used to avoid
212 confusing a regular value with an overflow value. */
215 avoid_overflow_infinity (tree val)
217 if (!is_overflow_infinity (val))
220 if (operand_equal_p (val, TYPE_MAX_VALUE (TREE_TYPE (val)), 0))
221 return TYPE_MAX_VALUE (TREE_TYPE (val));
224 #ifdef ENABLE_CHECKING
225 gcc_assert (operand_equal_p (val, TYPE_MIN_VALUE (TREE_TYPE (val)), 0));
227 return TYPE_MIN_VALUE (TREE_TYPE (val));
232 /* Return whether VAL is equal to the maximum value of its type. This
233 will be true for a positive overflow infinity. We can't do a
234 simple equality comparison with TYPE_MAX_VALUE because C typedefs
235 and Ada subtypes can produce types whose TYPE_MAX_VALUE is not ==
236 to the integer constant with the same value in the type. */
239 vrp_val_is_max (const_tree val)
241 tree type_max, type = TREE_TYPE (val);
243 /* For integer sub-types the values for the base type are relevant. */
244 if (TREE_TYPE (type))
245 type = TREE_TYPE (type);
246 type_max = TYPE_MAX_VALUE (type);
248 return (val == type_max
249 || (type_max != NULL_TREE
250 && operand_equal_p (val, type_max, 0)));
253 /* Return whether VAL is equal to the minimum value of its type. This
254 will be true for a negative overflow infinity. */
257 vrp_val_is_min (const_tree val)
259 tree type_min, type = TREE_TYPE (val);
261 /* For integer sub-types the values for the base type are relevant. */
262 if (TREE_TYPE (type))
263 type = TREE_TYPE (type);
264 type_min = TYPE_MIN_VALUE (type);
266 return (val == type_min
267 || (type_min != NULL_TREE
268 && operand_equal_p (val, type_min, 0)));
272 /* Return true if ARG is marked with the nonnull attribute in the
273 current function signature. */
276 nonnull_arg_p (const_tree arg)
278 tree t, attrs, fntype;
279 unsigned HOST_WIDE_INT arg_num;
281 gcc_assert (TREE_CODE (arg) == PARM_DECL && POINTER_TYPE_P (TREE_TYPE (arg)));
283 /* The static chain decl is always non null. */
284 if (arg == cfun->static_chain_decl)
287 fntype = TREE_TYPE (current_function_decl);
288 attrs = lookup_attribute ("nonnull", TYPE_ATTRIBUTES (fntype));
290 /* If "nonnull" wasn't specified, we know nothing about the argument. */
291 if (attrs == NULL_TREE)
294 /* If "nonnull" applies to all the arguments, then ARG is non-null. */
295 if (TREE_VALUE (attrs) == NULL_TREE)
298 /* Get the position number for ARG in the function signature. */
299 for (arg_num = 1, t = DECL_ARGUMENTS (current_function_decl);
301 t = TREE_CHAIN (t), arg_num++)
307 gcc_assert (t == arg);
309 /* Now see if ARG_NUM is mentioned in the nonnull list. */
310 for (t = TREE_VALUE (attrs); t; t = TREE_CHAIN (t))
312 if (compare_tree_int (TREE_VALUE (t), arg_num) == 0)
320 /* Set value range VR to VR_VARYING. */
323 set_value_range_to_varying (value_range_t *vr)
325 vr->type = VR_VARYING;
326 vr->min = vr->max = NULL_TREE;
328 bitmap_clear (vr->equiv);
332 /* Set value range VR to {T, MIN, MAX, EQUIV}. */
335 set_value_range (value_range_t *vr, enum value_range_type t, tree min,
336 tree max, bitmap equiv)
338 #if defined ENABLE_CHECKING
339 /* Check the validity of the range. */
340 if (t == VR_RANGE || t == VR_ANTI_RANGE)
344 gcc_assert (min && max);
346 if (INTEGRAL_TYPE_P (TREE_TYPE (min)) && t == VR_ANTI_RANGE)
347 gcc_assert (!vrp_val_is_min (min) || !vrp_val_is_max (max));
349 cmp = compare_values (min, max);
350 gcc_assert (cmp == 0 || cmp == -1 || cmp == -2);
352 if (needs_overflow_infinity (TREE_TYPE (min)))
353 gcc_assert (!is_overflow_infinity (min)
354 || !is_overflow_infinity (max));
357 if (t == VR_UNDEFINED || t == VR_VARYING)
358 gcc_assert (min == NULL_TREE && max == NULL_TREE);
360 if (t == VR_UNDEFINED || t == VR_VARYING)
361 gcc_assert (equiv == NULL || bitmap_empty_p (equiv));
368 /* Since updating the equivalence set involves deep copying the
369 bitmaps, only do it if absolutely necessary. */
370 if (vr->equiv == NULL
372 vr->equiv = BITMAP_ALLOC (NULL);
374 if (equiv != vr->equiv)
376 if (equiv && !bitmap_empty_p (equiv))
377 bitmap_copy (vr->equiv, equiv);
379 bitmap_clear (vr->equiv);
384 /* Set value range VR to the canonical form of {T, MIN, MAX, EQUIV}.
385 This means adjusting T, MIN and MAX representing the case of a
386 wrapping range with MAX < MIN covering [MIN, type_max] U [type_min, MAX]
387 as anti-rage ~[MAX+1, MIN-1]. Likewise for wrapping anti-ranges.
388 In corner cases where MAX+1 or MIN-1 wraps this will fall back
390 This routine exists to ease canonicalization in the case where we
391 extract ranges from var + CST op limit. */
394 set_and_canonicalize_value_range (value_range_t *vr, enum value_range_type t,
395 tree min, tree max, bitmap equiv)
400 && t != VR_ANTI_RANGE)
401 || TREE_CODE (min) != INTEGER_CST
402 || TREE_CODE (max) != INTEGER_CST
403 || !tree_int_cst_lt (max, min))
405 set_value_range (vr, t, min, max, equiv);
409 /* Wrong order for min and max, to swap them and the VR type we need
411 one = build_int_cst (TREE_TYPE (min), 1);
412 tmp = int_const_binop (PLUS_EXPR, max, one, 0);
413 max = int_const_binop (MINUS_EXPR, min, one, 0);
416 /* There's one corner case, if we had [C+1, C] before we now have
417 that again. But this represents an empty value range, so drop
418 to varying in this case. */
419 if (tree_int_cst_lt (max, min))
421 set_value_range_to_varying (vr);
425 t = t == VR_RANGE ? VR_ANTI_RANGE : VR_RANGE;
426 set_value_range (vr, t, min, max, equiv);
429 /* Copy value range FROM into value range TO. */
432 copy_value_range (value_range_t *to, value_range_t *from)
434 set_value_range (to, from->type, from->min, from->max, from->equiv);
437 /* Set value range VR to a single value. This function is only called
438 with values we get from statements, and exists to clear the
439 TREE_OVERFLOW flag so that we don't think we have an overflow
440 infinity when we shouldn't. */
443 set_value_range_to_value (value_range_t *vr, tree val, bitmap equiv)
445 gcc_assert (is_gimple_min_invariant (val));
446 val = avoid_overflow_infinity (val);
447 set_value_range (vr, VR_RANGE, val, val, equiv);
450 /* Set value range VR to a non-negative range of type TYPE.
451 OVERFLOW_INFINITY indicates whether to use an overflow infinity
452 rather than TYPE_MAX_VALUE; this should be true if we determine
453 that the range is nonnegative based on the assumption that signed
454 overflow does not occur. */
457 set_value_range_to_nonnegative (value_range_t *vr, tree type,
458 bool overflow_infinity)
462 if (overflow_infinity && !supports_overflow_infinity (type))
464 set_value_range_to_varying (vr);
468 zero = build_int_cst (type, 0);
469 set_value_range (vr, VR_RANGE, zero,
471 ? positive_overflow_infinity (type)
472 : TYPE_MAX_VALUE (type)),
476 /* Set value range VR to a non-NULL range of type TYPE. */
479 set_value_range_to_nonnull (value_range_t *vr, tree type)
481 tree zero = build_int_cst (type, 0);
482 set_value_range (vr, VR_ANTI_RANGE, zero, zero, vr->equiv);
486 /* Set value range VR to a NULL range of type TYPE. */
489 set_value_range_to_null (value_range_t *vr, tree type)
491 set_value_range_to_value (vr, build_int_cst (type, 0), vr->equiv);
495 /* Set value range VR to a range of a truthvalue of type TYPE. */
498 set_value_range_to_truthvalue (value_range_t *vr, tree type)
500 if (TYPE_PRECISION (type) == 1)
501 set_value_range_to_varying (vr);
503 set_value_range (vr, VR_RANGE,
504 build_int_cst (type, 0), build_int_cst (type, 1),
509 /* Set value range VR to VR_UNDEFINED. */
512 set_value_range_to_undefined (value_range_t *vr)
514 vr->type = VR_UNDEFINED;
515 vr->min = vr->max = NULL_TREE;
517 bitmap_clear (vr->equiv);
521 /* Return value range information for VAR.
523 If we have no values ranges recorded (ie, VRP is not running), then
524 return NULL. Otherwise create an empty range if none existed for VAR. */
526 static value_range_t *
527 get_value_range (const_tree var)
531 unsigned ver = SSA_NAME_VERSION (var);
533 /* If we have no recorded ranges, then return NULL. */
541 /* Create a default value range. */
542 vr_value[ver] = vr = XCNEW (value_range_t);
544 /* Defer allocating the equivalence set. */
547 /* If VAR is a default definition, the variable can take any value
549 sym = SSA_NAME_VAR (var);
550 if (SSA_NAME_IS_DEFAULT_DEF (var))
552 /* Try to use the "nonnull" attribute to create ~[0, 0]
553 anti-ranges for pointers. Note that this is only valid with
554 default definitions of PARM_DECLs. */
555 if (TREE_CODE (sym) == PARM_DECL
556 && POINTER_TYPE_P (TREE_TYPE (sym))
557 && nonnull_arg_p (sym))
558 set_value_range_to_nonnull (vr, TREE_TYPE (sym));
560 set_value_range_to_varying (vr);
566 /* Return true, if VAL1 and VAL2 are equal values for VRP purposes. */
569 vrp_operand_equal_p (const_tree val1, const_tree val2)
573 if (!val1 || !val2 || !operand_equal_p (val1, val2, 0))
575 if (is_overflow_infinity (val1))
576 return is_overflow_infinity (val2);
580 /* Return true, if the bitmaps B1 and B2 are equal. */
583 vrp_bitmap_equal_p (const_bitmap b1, const_bitmap b2)
587 && bitmap_equal_p (b1, b2)));
590 /* Update the value range and equivalence set for variable VAR to
591 NEW_VR. Return true if NEW_VR is different from VAR's previous
594 NOTE: This function assumes that NEW_VR is a temporary value range
595 object created for the sole purpose of updating VAR's range. The
596 storage used by the equivalence set from NEW_VR will be freed by
597 this function. Do not call update_value_range when NEW_VR
598 is the range object associated with another SSA name. */
601 update_value_range (const_tree var, value_range_t *new_vr)
603 value_range_t *old_vr;
606 /* Update the value range, if necessary. */
607 old_vr = get_value_range (var);
608 is_new = old_vr->type != new_vr->type
609 || !vrp_operand_equal_p (old_vr->min, new_vr->min)
610 || !vrp_operand_equal_p (old_vr->max, new_vr->max)
611 || !vrp_bitmap_equal_p (old_vr->equiv, new_vr->equiv);
614 set_value_range (old_vr, new_vr->type, new_vr->min, new_vr->max,
617 BITMAP_FREE (new_vr->equiv);
623 /* Add VAR and VAR's equivalence set to EQUIV. This is the central
624 point where equivalence processing can be turned on/off. */
627 add_equivalence (bitmap *equiv, const_tree var)
629 unsigned ver = SSA_NAME_VERSION (var);
630 value_range_t *vr = vr_value[ver];
633 *equiv = BITMAP_ALLOC (NULL);
634 bitmap_set_bit (*equiv, ver);
636 bitmap_ior_into (*equiv, vr->equiv);
640 /* Return true if VR is ~[0, 0]. */
643 range_is_nonnull (value_range_t *vr)
645 return vr->type == VR_ANTI_RANGE
646 && integer_zerop (vr->min)
647 && integer_zerop (vr->max);
651 /* Return true if VR is [0, 0]. */
654 range_is_null (value_range_t *vr)
656 return vr->type == VR_RANGE
657 && integer_zerop (vr->min)
658 && integer_zerop (vr->max);
662 /* Return true if value range VR involves at least one symbol. */
665 symbolic_range_p (value_range_t *vr)
667 return (!is_gimple_min_invariant (vr->min)
668 || !is_gimple_min_invariant (vr->max));
671 /* Return true if value range VR uses an overflow infinity. */
674 overflow_infinity_range_p (value_range_t *vr)
676 return (vr->type == VR_RANGE
677 && (is_overflow_infinity (vr->min)
678 || is_overflow_infinity (vr->max)));
681 /* Return false if we can not make a valid comparison based on VR;
682 this will be the case if it uses an overflow infinity and overflow
683 is not undefined (i.e., -fno-strict-overflow is in effect).
684 Otherwise return true, and set *STRICT_OVERFLOW_P to true if VR
685 uses an overflow infinity. */
688 usable_range_p (value_range_t *vr, bool *strict_overflow_p)
690 gcc_assert (vr->type == VR_RANGE);
691 if (is_overflow_infinity (vr->min))
693 *strict_overflow_p = true;
694 if (!TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (vr->min)))
697 if (is_overflow_infinity (vr->max))
699 *strict_overflow_p = true;
700 if (!TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (vr->max)))
707 /* Like tree_expr_nonnegative_warnv_p, but this function uses value
708 ranges obtained so far. */
711 vrp_expr_computes_nonnegative (tree expr, bool *strict_overflow_p)
713 return tree_expr_nonnegative_warnv_p (expr, strict_overflow_p);
716 /* Like tree_expr_nonzero_warnv_p, but this function uses value ranges
720 vrp_expr_computes_nonzero (tree expr, bool *strict_overflow_p)
722 if (tree_expr_nonzero_warnv_p (expr, strict_overflow_p))
725 /* If we have an expression of the form &X->a, then the expression
726 is nonnull if X is nonnull. */
727 if (TREE_CODE (expr) == ADDR_EXPR)
729 tree base = get_base_address (TREE_OPERAND (expr, 0));
731 if (base != NULL_TREE
732 && TREE_CODE (base) == INDIRECT_REF
733 && TREE_CODE (TREE_OPERAND (base, 0)) == SSA_NAME)
735 value_range_t *vr = get_value_range (TREE_OPERAND (base, 0));
736 if (range_is_nonnull (vr))
744 /* Returns true if EXPR is a valid value (as expected by compare_values) --
745 a gimple invariant, or SSA_NAME +- CST. */
748 valid_value_p (tree expr)
750 if (TREE_CODE (expr) == SSA_NAME)
753 if (TREE_CODE (expr) == PLUS_EXPR
754 || TREE_CODE (expr) == MINUS_EXPR)
755 return (TREE_CODE (TREE_OPERAND (expr, 0)) == SSA_NAME
756 && TREE_CODE (TREE_OPERAND (expr, 1)) == INTEGER_CST);
758 return is_gimple_min_invariant (expr);
764 -2 if those are incomparable. */
766 operand_less_p (tree val, tree val2)
768 /* LT is folded faster than GE and others. Inline the common case. */
769 if (TREE_CODE (val) == INTEGER_CST && TREE_CODE (val2) == INTEGER_CST)
771 if (TYPE_UNSIGNED (TREE_TYPE (val)))
772 return INT_CST_LT_UNSIGNED (val, val2);
775 if (INT_CST_LT (val, val2))
783 fold_defer_overflow_warnings ();
785 tcmp = fold_binary_to_constant (LT_EXPR, boolean_type_node, val, val2);
787 fold_undefer_and_ignore_overflow_warnings ();
790 || TREE_CODE (tcmp) != INTEGER_CST)
793 if (!integer_zerop (tcmp))
797 /* val >= val2, not considering overflow infinity. */
798 if (is_negative_overflow_infinity (val))
799 return is_negative_overflow_infinity (val2) ? 0 : 1;
800 else if (is_positive_overflow_infinity (val2))
801 return is_positive_overflow_infinity (val) ? 0 : 1;
806 /* Compare two values VAL1 and VAL2. Return
808 -2 if VAL1 and VAL2 cannot be compared at compile-time,
811 +1 if VAL1 > VAL2, and
814 This is similar to tree_int_cst_compare but supports pointer values
815 and values that cannot be compared at compile time.
817 If STRICT_OVERFLOW_P is not NULL, then set *STRICT_OVERFLOW_P to
818 true if the return value is only valid if we assume that signed
819 overflow is undefined. */
822 compare_values_warnv (tree val1, tree val2, bool *strict_overflow_p)
827 /* Below we rely on the fact that VAL1 and VAL2 are both pointers or
829 gcc_assert (POINTER_TYPE_P (TREE_TYPE (val1))
830 == POINTER_TYPE_P (TREE_TYPE (val2)));
831 /* Convert the two values into the same type. This is needed because
832 sizetype causes sign extension even for unsigned types. */
833 val2 = fold_convert (TREE_TYPE (val1), val2);
834 STRIP_USELESS_TYPE_CONVERSION (val2);
836 if ((TREE_CODE (val1) == SSA_NAME
837 || TREE_CODE (val1) == PLUS_EXPR
838 || TREE_CODE (val1) == MINUS_EXPR)
839 && (TREE_CODE (val2) == SSA_NAME
840 || TREE_CODE (val2) == PLUS_EXPR
841 || TREE_CODE (val2) == MINUS_EXPR))
844 enum tree_code code1, code2;
846 /* If VAL1 and VAL2 are of the form 'NAME [+-] CST' or 'NAME',
847 return -1 or +1 accordingly. If VAL1 and VAL2 don't use the
848 same name, return -2. */
849 if (TREE_CODE (val1) == SSA_NAME)
857 code1 = TREE_CODE (val1);
858 n1 = TREE_OPERAND (val1, 0);
859 c1 = TREE_OPERAND (val1, 1);
860 if (tree_int_cst_sgn (c1) == -1)
862 if (is_negative_overflow_infinity (c1))
864 c1 = fold_unary_to_constant (NEGATE_EXPR, TREE_TYPE (c1), c1);
867 code1 = code1 == MINUS_EXPR ? PLUS_EXPR : MINUS_EXPR;
871 if (TREE_CODE (val2) == SSA_NAME)
879 code2 = TREE_CODE (val2);
880 n2 = TREE_OPERAND (val2, 0);
881 c2 = TREE_OPERAND (val2, 1);
882 if (tree_int_cst_sgn (c2) == -1)
884 if (is_negative_overflow_infinity (c2))
886 c2 = fold_unary_to_constant (NEGATE_EXPR, TREE_TYPE (c2), c2);
889 code2 = code2 == MINUS_EXPR ? PLUS_EXPR : MINUS_EXPR;
893 /* Both values must use the same name. */
897 if (code1 == SSA_NAME
898 && code2 == SSA_NAME)
902 /* If overflow is defined we cannot simplify more. */
903 if (!TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (val1)))
906 if (strict_overflow_p != NULL
907 && (code1 == SSA_NAME || !TREE_NO_WARNING (val1))
908 && (code2 == SSA_NAME || !TREE_NO_WARNING (val2)))
909 *strict_overflow_p = true;
911 if (code1 == SSA_NAME)
913 if (code2 == PLUS_EXPR)
914 /* NAME < NAME + CST */
916 else if (code2 == MINUS_EXPR)
917 /* NAME > NAME - CST */
920 else if (code1 == PLUS_EXPR)
922 if (code2 == SSA_NAME)
923 /* NAME + CST > NAME */
925 else if (code2 == PLUS_EXPR)
926 /* NAME + CST1 > NAME + CST2, if CST1 > CST2 */
927 return compare_values_warnv (c1, c2, strict_overflow_p);
928 else if (code2 == MINUS_EXPR)
929 /* NAME + CST1 > NAME - CST2 */
932 else if (code1 == MINUS_EXPR)
934 if (code2 == SSA_NAME)
935 /* NAME - CST < NAME */
937 else if (code2 == PLUS_EXPR)
938 /* NAME - CST1 < NAME + CST2 */
940 else if (code2 == MINUS_EXPR)
941 /* NAME - CST1 > NAME - CST2, if CST1 < CST2. Notice that
942 C1 and C2 are swapped in the call to compare_values. */
943 return compare_values_warnv (c2, c1, strict_overflow_p);
949 /* We cannot compare non-constants. */
950 if (!is_gimple_min_invariant (val1) || !is_gimple_min_invariant (val2))
953 if (!POINTER_TYPE_P (TREE_TYPE (val1)))
955 /* We cannot compare overflowed values, except for overflow
957 if (TREE_OVERFLOW (val1) || TREE_OVERFLOW (val2))
959 if (strict_overflow_p != NULL)
960 *strict_overflow_p = true;
961 if (is_negative_overflow_infinity (val1))
962 return is_negative_overflow_infinity (val2) ? 0 : -1;
963 else if (is_negative_overflow_infinity (val2))
965 else if (is_positive_overflow_infinity (val1))
966 return is_positive_overflow_infinity (val2) ? 0 : 1;
967 else if (is_positive_overflow_infinity (val2))
972 return tree_int_cst_compare (val1, val2);
978 /* First see if VAL1 and VAL2 are not the same. */
979 if (val1 == val2 || operand_equal_p (val1, val2, 0))
982 /* If VAL1 is a lower address than VAL2, return -1. */
983 if (operand_less_p (val1, val2) == 1)
986 /* If VAL1 is a higher address than VAL2, return +1. */
987 if (operand_less_p (val2, val1) == 1)
990 /* If VAL1 is different than VAL2, return +2.
991 For integer constants we either have already returned -1 or 1
992 or they are equivalent. We still might succeed in proving
993 something about non-trivial operands. */
994 if (TREE_CODE (val1) != INTEGER_CST
995 || TREE_CODE (val2) != INTEGER_CST)
997 t = fold_binary_to_constant (NE_EXPR, boolean_type_node, val1, val2);
998 if (t && integer_onep (t))
1006 /* Compare values like compare_values_warnv, but treat comparisons of
1007 nonconstants which rely on undefined overflow as incomparable. */
1010 compare_values (tree val1, tree val2)
1016 ret = compare_values_warnv (val1, val2, &sop);
1018 && (!is_gimple_min_invariant (val1) || !is_gimple_min_invariant (val2)))
1024 /* Return 1 if VAL is inside value range VR (VR->MIN <= VAL <= VR->MAX),
1025 0 if VAL is not inside VR,
1026 -2 if we cannot tell either way.
1028 FIXME, the current semantics of this functions are a bit quirky
1029 when taken in the context of VRP. In here we do not care
1030 about VR's type. If VR is the anti-range ~[3, 5] the call
1031 value_inside_range (4, VR) will return 1.
1033 This is counter-intuitive in a strict sense, but the callers
1034 currently expect this. They are calling the function
1035 merely to determine whether VR->MIN <= VAL <= VR->MAX. The
1036 callers are applying the VR_RANGE/VR_ANTI_RANGE semantics
1039 This also applies to value_ranges_intersect_p and
1040 range_includes_zero_p. The semantics of VR_RANGE and
1041 VR_ANTI_RANGE should be encoded here, but that also means
1042 adapting the users of these functions to the new semantics.
1044 Benchmark compile/20001226-1.c compilation time after changing this
1048 value_inside_range (tree val, value_range_t * vr)
1052 cmp1 = operand_less_p (val, vr->min);
1058 cmp2 = operand_less_p (vr->max, val);
1066 /* Return true if value ranges VR0 and VR1 have a non-empty
1069 Benchmark compile/20001226-1.c compilation time after changing this
1074 value_ranges_intersect_p (value_range_t *vr0, value_range_t *vr1)
1076 /* The value ranges do not intersect if the maximum of the first range is
1077 less than the minimum of the second range or vice versa.
1078 When those relations are unknown, we can't do any better. */
1079 if (operand_less_p (vr0->max, vr1->min) != 0)
1081 if (operand_less_p (vr1->max, vr0->min) != 0)
1087 /* Return true if VR includes the value zero, false otherwise. FIXME,
1088 currently this will return false for an anti-range like ~[-4, 3].
1089 This will be wrong when the semantics of value_inside_range are
1090 modified (currently the users of this function expect these
1094 range_includes_zero_p (value_range_t *vr)
1098 gcc_assert (vr->type != VR_UNDEFINED
1099 && vr->type != VR_VARYING
1100 && !symbolic_range_p (vr));
1102 zero = build_int_cst (TREE_TYPE (vr->min), 0);
1103 return (value_inside_range (zero, vr) == 1);
1106 /* Return true if T, an SSA_NAME, is known to be nonnegative. Return
1107 false otherwise or if no value range information is available. */
1110 ssa_name_nonnegative_p (const_tree t)
1112 value_range_t *vr = get_value_range (t);
1117 /* Testing for VR_ANTI_RANGE is not useful here as any anti-range
1118 which would return a useful value should be encoded as a VR_RANGE. */
1119 if (vr->type == VR_RANGE)
1121 int result = compare_values (vr->min, integer_zero_node);
1123 return (result == 0 || result == 1);
1128 /* Return true if T, an SSA_NAME, is known to be nonzero. Return
1129 false otherwise or if no value range information is available. */
1132 ssa_name_nonzero_p (const_tree t)
1134 value_range_t *vr = get_value_range (t);
1139 /* A VR_RANGE which does not include zero is a nonzero value. */
1140 if (vr->type == VR_RANGE && !symbolic_range_p (vr))
1141 return ! range_includes_zero_p (vr);
1143 /* A VR_ANTI_RANGE which does include zero is a nonzero value. */
1144 if (vr->type == VR_ANTI_RANGE && !symbolic_range_p (vr))
1145 return range_includes_zero_p (vr);
1151 /* Extract value range information from an ASSERT_EXPR EXPR and store
1155 extract_range_from_assert (value_range_t *vr_p, tree expr)
1157 tree var, cond, limit, min, max, type;
1158 value_range_t *var_vr, *limit_vr;
1159 enum tree_code cond_code;
1161 var = ASSERT_EXPR_VAR (expr);
1162 cond = ASSERT_EXPR_COND (expr);
1164 gcc_assert (COMPARISON_CLASS_P (cond));
1166 /* Find VAR in the ASSERT_EXPR conditional. */
1167 if (var == TREE_OPERAND (cond, 0)
1168 || TREE_CODE (TREE_OPERAND (cond, 0)) == PLUS_EXPR
1169 || TREE_CODE (TREE_OPERAND (cond, 0)) == NOP_EXPR)
1171 /* If the predicate is of the form VAR COMP LIMIT, then we just
1172 take LIMIT from the RHS and use the same comparison code. */
1173 cond_code = TREE_CODE (cond);
1174 limit = TREE_OPERAND (cond, 1);
1175 cond = TREE_OPERAND (cond, 0);
1179 /* If the predicate is of the form LIMIT COMP VAR, then we need
1180 to flip around the comparison code to create the proper range
1182 cond_code = swap_tree_comparison (TREE_CODE (cond));
1183 limit = TREE_OPERAND (cond, 0);
1184 cond = TREE_OPERAND (cond, 1);
1187 limit = avoid_overflow_infinity (limit);
1189 type = TREE_TYPE (limit);
1190 gcc_assert (limit != var);
1192 /* For pointer arithmetic, we only keep track of pointer equality
1194 if (POINTER_TYPE_P (type) && cond_code != NE_EXPR && cond_code != EQ_EXPR)
1196 set_value_range_to_varying (vr_p);
1200 /* If LIMIT is another SSA name and LIMIT has a range of its own,
1201 try to use LIMIT's range to avoid creating symbolic ranges
1203 limit_vr = (TREE_CODE (limit) == SSA_NAME) ? get_value_range (limit) : NULL;
1205 /* LIMIT's range is only interesting if it has any useful information. */
1207 && (limit_vr->type == VR_UNDEFINED
1208 || limit_vr->type == VR_VARYING
1209 || symbolic_range_p (limit_vr)))
1212 /* Initially, the new range has the same set of equivalences of
1213 VAR's range. This will be revised before returning the final
1214 value. Since assertions may be chained via mutually exclusive
1215 predicates, we will need to trim the set of equivalences before
1217 gcc_assert (vr_p->equiv == NULL);
1218 add_equivalence (&vr_p->equiv, var);
1220 /* Extract a new range based on the asserted comparison for VAR and
1221 LIMIT's value range. Notice that if LIMIT has an anti-range, we
1222 will only use it for equality comparisons (EQ_EXPR). For any
1223 other kind of assertion, we cannot derive a range from LIMIT's
1224 anti-range that can be used to describe the new range. For
1225 instance, ASSERT_EXPR <x_2, x_2 <= b_4>. If b_4 is ~[2, 10],
1226 then b_4 takes on the ranges [-INF, 1] and [11, +INF]. There is
1227 no single range for x_2 that could describe LE_EXPR, so we might
1228 as well build the range [b_4, +INF] for it.
1229 One special case we handle is extracting a range from a
1230 range test encoded as (unsigned)var + CST <= limit. */
1231 if (TREE_CODE (cond) == NOP_EXPR
1232 || TREE_CODE (cond) == PLUS_EXPR)
1234 tree cst2 = NULL_TREE;
1236 if (TREE_CODE (cond) == PLUS_EXPR)
1238 min = TREE_OPERAND (cond, 1);
1239 cst2 = fold_build1 (NEGATE_EXPR, TREE_TYPE (min), min);
1240 min = fold_convert (TREE_TYPE (var), cst2);
1241 cond = TREE_OPERAND (cond, 0);
1244 min = build_int_cst (TREE_TYPE (var), 0);
1246 if (cst2 != NULL_TREE)
1247 max = int_const_binop (PLUS_EXPR, limit, min, 0);
1250 max = fold_convert (TREE_TYPE (var), max);
1252 /* We can transform a max, min range to an anti-range or
1253 vice-versa. Use set_and_canonicalize_value_range which does
1255 if (cond_code == LE_EXPR)
1256 set_and_canonicalize_value_range (vr_p, VR_RANGE,
1257 min, max, vr_p->equiv);
1258 else if (cond_code == GT_EXPR)
1259 set_and_canonicalize_value_range (vr_p, VR_ANTI_RANGE,
1260 min, max, vr_p->equiv);
1264 else if (cond_code == EQ_EXPR)
1266 enum value_range_type range_type;
1270 range_type = limit_vr->type;
1271 min = limit_vr->min;
1272 max = limit_vr->max;
1276 range_type = VR_RANGE;
1281 set_value_range (vr_p, range_type, min, max, vr_p->equiv);
1283 /* When asserting the equality VAR == LIMIT and LIMIT is another
1284 SSA name, the new range will also inherit the equivalence set
1286 if (TREE_CODE (limit) == SSA_NAME)
1287 add_equivalence (&vr_p->equiv, limit);
1289 else if (cond_code == NE_EXPR)
1291 /* As described above, when LIMIT's range is an anti-range and
1292 this assertion is an inequality (NE_EXPR), then we cannot
1293 derive anything from the anti-range. For instance, if
1294 LIMIT's range was ~[0, 0], the assertion 'VAR != LIMIT' does
1295 not imply that VAR's range is [0, 0]. So, in the case of
1296 anti-ranges, we just assert the inequality using LIMIT and
1299 If LIMIT_VR is a range, we can only use it to build a new
1300 anti-range if LIMIT_VR is a single-valued range. For
1301 instance, if LIMIT_VR is [0, 1], the predicate
1302 VAR != [0, 1] does not mean that VAR's range is ~[0, 1].
1303 Rather, it means that for value 0 VAR should be ~[0, 0]
1304 and for value 1, VAR should be ~[1, 1]. We cannot
1305 represent these ranges.
1307 The only situation in which we can build a valid
1308 anti-range is when LIMIT_VR is a single-valued range
1309 (i.e., LIMIT_VR->MIN == LIMIT_VR->MAX). In that case,
1310 build the anti-range ~[LIMIT_VR->MIN, LIMIT_VR->MAX]. */
1312 && limit_vr->type == VR_RANGE
1313 && compare_values (limit_vr->min, limit_vr->max) == 0)
1315 min = limit_vr->min;
1316 max = limit_vr->max;
1320 /* In any other case, we cannot use LIMIT's range to build a
1321 valid anti-range. */
1325 /* If MIN and MAX cover the whole range for their type, then
1326 just use the original LIMIT. */
1327 if (INTEGRAL_TYPE_P (type)
1328 && vrp_val_is_min (min)
1329 && vrp_val_is_max (max))
1332 set_value_range (vr_p, VR_ANTI_RANGE, min, max, vr_p->equiv);
1334 else if (cond_code == LE_EXPR || cond_code == LT_EXPR)
1336 min = TYPE_MIN_VALUE (type);
1338 if (limit_vr == NULL || limit_vr->type == VR_ANTI_RANGE)
1342 /* If LIMIT_VR is of the form [N1, N2], we need to build the
1343 range [MIN, N2] for LE_EXPR and [MIN, N2 - 1] for
1345 max = limit_vr->max;
1348 /* If the maximum value forces us to be out of bounds, simply punt.
1349 It would be pointless to try and do anything more since this
1350 all should be optimized away above us. */
1351 if ((cond_code == LT_EXPR
1352 && compare_values (max, min) == 0)
1353 || is_overflow_infinity (max))
1354 set_value_range_to_varying (vr_p);
1357 /* For LT_EXPR, we create the range [MIN, MAX - 1]. */
1358 if (cond_code == LT_EXPR)
1360 tree one = build_int_cst (type, 1);
1361 max = fold_build2 (MINUS_EXPR, type, max, one);
1363 TREE_NO_WARNING (max) = 1;
1366 set_value_range (vr_p, VR_RANGE, min, max, vr_p->equiv);
1369 else if (cond_code == GE_EXPR || cond_code == GT_EXPR)
1371 max = TYPE_MAX_VALUE (type);
1373 if (limit_vr == NULL || limit_vr->type == VR_ANTI_RANGE)
1377 /* If LIMIT_VR is of the form [N1, N2], we need to build the
1378 range [N1, MAX] for GE_EXPR and [N1 + 1, MAX] for
1380 min = limit_vr->min;
1383 /* If the minimum value forces us to be out of bounds, simply punt.
1384 It would be pointless to try and do anything more since this
1385 all should be optimized away above us. */
1386 if ((cond_code == GT_EXPR
1387 && compare_values (min, max) == 0)
1388 || is_overflow_infinity (min))
1389 set_value_range_to_varying (vr_p);
1392 /* For GT_EXPR, we create the range [MIN + 1, MAX]. */
1393 if (cond_code == GT_EXPR)
1395 tree one = build_int_cst (type, 1);
1396 min = fold_build2 (PLUS_EXPR, type, min, one);
1398 TREE_NO_WARNING (min) = 1;
1401 set_value_range (vr_p, VR_RANGE, min, max, vr_p->equiv);
1407 /* If VAR already had a known range, it may happen that the new
1408 range we have computed and VAR's range are not compatible. For
1412 p_6 = ASSERT_EXPR <p_5, p_5 == NULL>;
1414 p_8 = ASSERT_EXPR <p_6, p_6 != NULL>;
1416 While the above comes from a faulty program, it will cause an ICE
1417 later because p_8 and p_6 will have incompatible ranges and at
1418 the same time will be considered equivalent. A similar situation
1422 i_6 = ASSERT_EXPR <i_5, i_5 > 10>;
1424 i_7 = ASSERT_EXPR <i_6, i_6 < 5>;
1426 Again i_6 and i_7 will have incompatible ranges. It would be
1427 pointless to try and do anything with i_7's range because
1428 anything dominated by 'if (i_5 < 5)' will be optimized away.
1429 Note, due to the wa in which simulation proceeds, the statement
1430 i_7 = ASSERT_EXPR <...> we would never be visited because the
1431 conditional 'if (i_5 < 5)' always evaluates to false. However,
1432 this extra check does not hurt and may protect against future
1433 changes to VRP that may get into a situation similar to the
1434 NULL pointer dereference example.
1436 Note that these compatibility tests are only needed when dealing
1437 with ranges or a mix of range and anti-range. If VAR_VR and VR_P
1438 are both anti-ranges, they will always be compatible, because two
1439 anti-ranges will always have a non-empty intersection. */
1441 var_vr = get_value_range (var);
1443 /* We may need to make adjustments when VR_P and VAR_VR are numeric
1444 ranges or anti-ranges. */
1445 if (vr_p->type == VR_VARYING
1446 || vr_p->type == VR_UNDEFINED
1447 || var_vr->type == VR_VARYING
1448 || var_vr->type == VR_UNDEFINED
1449 || symbolic_range_p (vr_p)
1450 || symbolic_range_p (var_vr))
1453 if (var_vr->type == VR_RANGE && vr_p->type == VR_RANGE)
1455 /* If the two ranges have a non-empty intersection, we can
1456 refine the resulting range. Since the assert expression
1457 creates an equivalency and at the same time it asserts a
1458 predicate, we can take the intersection of the two ranges to
1459 get better precision. */
1460 if (value_ranges_intersect_p (var_vr, vr_p))
1462 /* Use the larger of the two minimums. */
1463 if (compare_values (vr_p->min, var_vr->min) == -1)
1468 /* Use the smaller of the two maximums. */
1469 if (compare_values (vr_p->max, var_vr->max) == 1)
1474 set_value_range (vr_p, vr_p->type, min, max, vr_p->equiv);
1478 /* The two ranges do not intersect, set the new range to
1479 VARYING, because we will not be able to do anything
1480 meaningful with it. */
1481 set_value_range_to_varying (vr_p);
1484 else if ((var_vr->type == VR_RANGE && vr_p->type == VR_ANTI_RANGE)
1485 || (var_vr->type == VR_ANTI_RANGE && vr_p->type == VR_RANGE))
1487 /* A range and an anti-range will cancel each other only if
1488 their ends are the same. For instance, in the example above,
1489 p_8's range ~[0, 0] and p_6's range [0, 0] are incompatible,
1490 so VR_P should be set to VR_VARYING. */
1491 if (compare_values (var_vr->min, vr_p->min) == 0
1492 && compare_values (var_vr->max, vr_p->max) == 0)
1493 set_value_range_to_varying (vr_p);
1496 tree min, max, anti_min, anti_max, real_min, real_max;
1499 /* We want to compute the logical AND of the two ranges;
1500 there are three cases to consider.
1503 1. The VR_ANTI_RANGE range is completely within the
1504 VR_RANGE and the endpoints of the ranges are
1505 different. In that case the resulting range
1506 should be whichever range is more precise.
1507 Typically that will be the VR_RANGE.
1509 2. The VR_ANTI_RANGE is completely disjoint from
1510 the VR_RANGE. In this case the resulting range
1511 should be the VR_RANGE.
1513 3. There is some overlap between the VR_ANTI_RANGE
1516 3a. If the high limit of the VR_ANTI_RANGE resides
1517 within the VR_RANGE, then the result is a new
1518 VR_RANGE starting at the high limit of the
1519 the VR_ANTI_RANGE + 1 and extending to the
1520 high limit of the original VR_RANGE.
1522 3b. If the low limit of the VR_ANTI_RANGE resides
1523 within the VR_RANGE, then the result is a new
1524 VR_RANGE starting at the low limit of the original
1525 VR_RANGE and extending to the low limit of the
1526 VR_ANTI_RANGE - 1. */
1527 if (vr_p->type == VR_ANTI_RANGE)
1529 anti_min = vr_p->min;
1530 anti_max = vr_p->max;
1531 real_min = var_vr->min;
1532 real_max = var_vr->max;
1536 anti_min = var_vr->min;
1537 anti_max = var_vr->max;
1538 real_min = vr_p->min;
1539 real_max = vr_p->max;
1543 /* Case 1, VR_ANTI_RANGE completely within VR_RANGE,
1544 not including any endpoints. */
1545 if (compare_values (anti_max, real_max) == -1
1546 && compare_values (anti_min, real_min) == 1)
1548 set_value_range (vr_p, VR_RANGE, real_min,
1549 real_max, vr_p->equiv);
1551 /* Case 2, VR_ANTI_RANGE completely disjoint from
1553 else if (compare_values (anti_min, real_max) == 1
1554 || compare_values (anti_max, real_min) == -1)
1556 set_value_range (vr_p, VR_RANGE, real_min,
1557 real_max, vr_p->equiv);
1559 /* Case 3a, the anti-range extends into the low
1560 part of the real range. Thus creating a new
1561 low for the real range. */
1562 else if (((cmp = compare_values (anti_max, real_min)) == 1
1564 && compare_values (anti_max, real_max) == -1)
1566 gcc_assert (!is_positive_overflow_infinity (anti_max));
1567 if (needs_overflow_infinity (TREE_TYPE (anti_max))
1568 && vrp_val_is_max (anti_max))
1570 if (!supports_overflow_infinity (TREE_TYPE (var_vr->min)))
1572 set_value_range_to_varying (vr_p);
1575 min = positive_overflow_infinity (TREE_TYPE (var_vr->min));
1577 else if (!POINTER_TYPE_P (TREE_TYPE (var_vr->min)))
1578 min = fold_build2 (PLUS_EXPR, TREE_TYPE (var_vr->min),
1580 build_int_cst (TREE_TYPE (var_vr->min), 1));
1582 min = fold_build2 (POINTER_PLUS_EXPR, TREE_TYPE (var_vr->min),
1583 anti_max, size_int (1));
1585 set_value_range (vr_p, VR_RANGE, min, max, vr_p->equiv);
1587 /* Case 3b, the anti-range extends into the high
1588 part of the real range. Thus creating a new
1589 higher for the real range. */
1590 else if (compare_values (anti_min, real_min) == 1
1591 && ((cmp = compare_values (anti_min, real_max)) == -1
1594 gcc_assert (!is_negative_overflow_infinity (anti_min));
1595 if (needs_overflow_infinity (TREE_TYPE (anti_min))
1596 && vrp_val_is_min (anti_min))
1598 if (!supports_overflow_infinity (TREE_TYPE (var_vr->min)))
1600 set_value_range_to_varying (vr_p);
1603 max = negative_overflow_infinity (TREE_TYPE (var_vr->min));
1605 else if (!POINTER_TYPE_P (TREE_TYPE (var_vr->min)))
1606 max = fold_build2 (MINUS_EXPR, TREE_TYPE (var_vr->min),
1608 build_int_cst (TREE_TYPE (var_vr->min), 1));
1610 max = fold_build2 (POINTER_PLUS_EXPR, TREE_TYPE (var_vr->min),
1614 set_value_range (vr_p, VR_RANGE, min, max, vr_p->equiv);
1621 /* Extract range information from SSA name VAR and store it in VR. If
1622 VAR has an interesting range, use it. Otherwise, create the
1623 range [VAR, VAR] and return it. This is useful in situations where
1624 we may have conditionals testing values of VARYING names. For
1631 Even if y_5 is deemed VARYING, we can determine that x_3 > y_5 is
1635 extract_range_from_ssa_name (value_range_t *vr, tree var)
1637 value_range_t *var_vr = get_value_range (var);
1639 if (var_vr->type != VR_UNDEFINED && var_vr->type != VR_VARYING)
1640 copy_value_range (vr, var_vr);
1642 set_value_range (vr, VR_RANGE, var, var, NULL);
1644 add_equivalence (&vr->equiv, var);
1648 /* Wrapper around int_const_binop. If the operation overflows and we
1649 are not using wrapping arithmetic, then adjust the result to be
1650 -INF or +INF depending on CODE, VAL1 and VAL2. This can return
1651 NULL_TREE if we need to use an overflow infinity representation but
1652 the type does not support it. */
1655 vrp_int_const_binop (enum tree_code code, tree val1, tree val2)
1659 res = int_const_binop (code, val1, val2, 0);
1661 /* If we are not using wrapping arithmetic, operate symbolically
1662 on -INF and +INF. */
1663 if (TYPE_OVERFLOW_WRAPS (TREE_TYPE (val1)))
1665 int checkz = compare_values (res, val1);
1666 bool overflow = false;
1668 /* Ensure that res = val1 [+*] val2 >= val1
1669 or that res = val1 - val2 <= val1. */
1670 if ((code == PLUS_EXPR
1671 && !(checkz == 1 || checkz == 0))
1672 || (code == MINUS_EXPR
1673 && !(checkz == 0 || checkz == -1)))
1677 /* Checking for multiplication overflow is done by dividing the
1678 output of the multiplication by the first input of the
1679 multiplication. If the result of that division operation is
1680 not equal to the second input of the multiplication, then the
1681 multiplication overflowed. */
1682 else if (code == MULT_EXPR && !integer_zerop (val1))
1684 tree tmp = int_const_binop (TRUNC_DIV_EXPR,
1687 int check = compare_values (tmp, val2);
1695 res = copy_node (res);
1696 TREE_OVERFLOW (res) = 1;
1700 else if ((TREE_OVERFLOW (res)
1701 && !TREE_OVERFLOW (val1)
1702 && !TREE_OVERFLOW (val2))
1703 || is_overflow_infinity (val1)
1704 || is_overflow_infinity (val2))
1706 /* If the operation overflowed but neither VAL1 nor VAL2 are
1707 overflown, return -INF or +INF depending on the operation
1708 and the combination of signs of the operands. */
1709 int sgn1 = tree_int_cst_sgn (val1);
1710 int sgn2 = tree_int_cst_sgn (val2);
1712 if (needs_overflow_infinity (TREE_TYPE (res))
1713 && !supports_overflow_infinity (TREE_TYPE (res)))
1716 /* We have to punt on adding infinities of different signs,
1717 since we can't tell what the sign of the result should be.
1718 Likewise for subtracting infinities of the same sign. */
1719 if (((code == PLUS_EXPR && sgn1 != sgn2)
1720 || (code == MINUS_EXPR && sgn1 == sgn2))
1721 && is_overflow_infinity (val1)
1722 && is_overflow_infinity (val2))
1725 /* Don't try to handle division or shifting of infinities. */
1726 if ((code == TRUNC_DIV_EXPR
1727 || code == FLOOR_DIV_EXPR
1728 || code == CEIL_DIV_EXPR
1729 || code == EXACT_DIV_EXPR
1730 || code == ROUND_DIV_EXPR
1731 || code == RSHIFT_EXPR)
1732 && (is_overflow_infinity (val1)
1733 || is_overflow_infinity (val2)))
1736 /* Notice that we only need to handle the restricted set of
1737 operations handled by extract_range_from_binary_expr.
1738 Among them, only multiplication, addition and subtraction
1739 can yield overflow without overflown operands because we
1740 are working with integral types only... except in the
1741 case VAL1 = -INF and VAL2 = -1 which overflows to +INF
1742 for division too. */
1744 /* For multiplication, the sign of the overflow is given
1745 by the comparison of the signs of the operands. */
1746 if ((code == MULT_EXPR && sgn1 == sgn2)
1747 /* For addition, the operands must be of the same sign
1748 to yield an overflow. Its sign is therefore that
1749 of one of the operands, for example the first. For
1750 infinite operands X + -INF is negative, not positive. */
1751 || (code == PLUS_EXPR
1753 ? !is_negative_overflow_infinity (val2)
1754 : is_positive_overflow_infinity (val2)))
1755 /* For subtraction, non-infinite operands must be of
1756 different signs to yield an overflow. Its sign is
1757 therefore that of the first operand or the opposite of
1758 that of the second operand. A first operand of 0 counts
1759 as positive here, for the corner case 0 - (-INF), which
1760 overflows, but must yield +INF. For infinite operands 0
1761 - INF is negative, not positive. */
1762 || (code == MINUS_EXPR
1764 ? !is_positive_overflow_infinity (val2)
1765 : is_negative_overflow_infinity (val2)))
1766 /* We only get in here with positive shift count, so the
1767 overflow direction is the same as the sign of val1.
1768 Actually rshift does not overflow at all, but we only
1769 handle the case of shifting overflowed -INF and +INF. */
1770 || (code == RSHIFT_EXPR
1772 /* For division, the only case is -INF / -1 = +INF. */
1773 || code == TRUNC_DIV_EXPR
1774 || code == FLOOR_DIV_EXPR
1775 || code == CEIL_DIV_EXPR
1776 || code == EXACT_DIV_EXPR
1777 || code == ROUND_DIV_EXPR)
1778 return (needs_overflow_infinity (TREE_TYPE (res))
1779 ? positive_overflow_infinity (TREE_TYPE (res))
1780 : TYPE_MAX_VALUE (TREE_TYPE (res)));
1782 return (needs_overflow_infinity (TREE_TYPE (res))
1783 ? negative_overflow_infinity (TREE_TYPE (res))
1784 : TYPE_MIN_VALUE (TREE_TYPE (res)));
1791 /* Extract range information from a binary expression EXPR based on
1792 the ranges of each of its operands and the expression code. */
1795 extract_range_from_binary_expr (value_range_t *vr, tree expr)
1797 enum tree_code code = TREE_CODE (expr);
1798 enum value_range_type type;
1799 tree op0, op1, min, max;
1801 value_range_t vr0 = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
1802 value_range_t vr1 = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
1804 /* Not all binary expressions can be applied to ranges in a
1805 meaningful way. Handle only arithmetic operations. */
1806 if (code != PLUS_EXPR
1807 && code != MINUS_EXPR
1808 && code != POINTER_PLUS_EXPR
1809 && code != MULT_EXPR
1810 && code != TRUNC_DIV_EXPR
1811 && code != FLOOR_DIV_EXPR
1812 && code != CEIL_DIV_EXPR
1813 && code != EXACT_DIV_EXPR
1814 && code != ROUND_DIV_EXPR
1815 && code != RSHIFT_EXPR
1818 && code != BIT_AND_EXPR
1819 && code != TRUTH_ANDIF_EXPR
1820 && code != TRUTH_ORIF_EXPR
1821 && code != TRUTH_AND_EXPR
1822 && code != TRUTH_OR_EXPR)
1824 set_value_range_to_varying (vr);
1828 /* Get value ranges for each operand. For constant operands, create
1829 a new value range with the operand to simplify processing. */
1830 op0 = TREE_OPERAND (expr, 0);
1831 if (TREE_CODE (op0) == SSA_NAME)
1832 vr0 = *(get_value_range (op0));
1833 else if (is_gimple_min_invariant (op0))
1834 set_value_range_to_value (&vr0, op0, NULL);
1836 set_value_range_to_varying (&vr0);
1838 op1 = TREE_OPERAND (expr, 1);
1839 if (TREE_CODE (op1) == SSA_NAME)
1840 vr1 = *(get_value_range (op1));
1841 else if (is_gimple_min_invariant (op1))
1842 set_value_range_to_value (&vr1, op1, NULL);
1844 set_value_range_to_varying (&vr1);
1846 /* If either range is UNDEFINED, so is the result. */
1847 if (vr0.type == VR_UNDEFINED || vr1.type == VR_UNDEFINED)
1849 set_value_range_to_undefined (vr);
1853 /* The type of the resulting value range defaults to VR0.TYPE. */
1856 /* Refuse to operate on VARYING ranges, ranges of different kinds
1857 and symbolic ranges. As an exception, we allow BIT_AND_EXPR
1858 because we may be able to derive a useful range even if one of
1859 the operands is VR_VARYING or symbolic range. TODO, we may be
1860 able to derive anti-ranges in some cases. */
1861 if (code != BIT_AND_EXPR
1862 && code != TRUTH_AND_EXPR
1863 && code != TRUTH_OR_EXPR
1864 && (vr0.type == VR_VARYING
1865 || vr1.type == VR_VARYING
1866 || vr0.type != vr1.type
1867 || symbolic_range_p (&vr0)
1868 || symbolic_range_p (&vr1)))
1870 set_value_range_to_varying (vr);
1874 /* Now evaluate the expression to determine the new range. */
1875 if (POINTER_TYPE_P (TREE_TYPE (expr))
1876 || POINTER_TYPE_P (TREE_TYPE (op0))
1877 || POINTER_TYPE_P (TREE_TYPE (op1)))
1879 if (code == MIN_EXPR || code == MAX_EXPR)
1881 /* For MIN/MAX expressions with pointers, we only care about
1882 nullness, if both are non null, then the result is nonnull.
1883 If both are null, then the result is null. Otherwise they
1885 if (range_is_nonnull (&vr0) && range_is_nonnull (&vr1))
1886 set_value_range_to_nonnull (vr, TREE_TYPE (expr));
1887 else if (range_is_null (&vr0) && range_is_null (&vr1))
1888 set_value_range_to_null (vr, TREE_TYPE (expr));
1890 set_value_range_to_varying (vr);
1894 gcc_assert (code == POINTER_PLUS_EXPR);
1895 /* For pointer types, we are really only interested in asserting
1896 whether the expression evaluates to non-NULL. */
1897 if (range_is_nonnull (&vr0) || range_is_nonnull (&vr1))
1898 set_value_range_to_nonnull (vr, TREE_TYPE (expr));
1899 else if (range_is_null (&vr0) && range_is_null (&vr1))
1900 set_value_range_to_null (vr, TREE_TYPE (expr));
1902 set_value_range_to_varying (vr);
1907 /* For integer ranges, apply the operation to each end of the
1908 range and see what we end up with. */
1909 if (code == TRUTH_ANDIF_EXPR
1910 || code == TRUTH_ORIF_EXPR
1911 || code == TRUTH_AND_EXPR
1912 || code == TRUTH_OR_EXPR)
1914 /* If one of the operands is zero, we know that the whole
1915 expression evaluates zero. */
1916 if (code == TRUTH_AND_EXPR
1917 && ((vr0.type == VR_RANGE
1918 && integer_zerop (vr0.min)
1919 && integer_zerop (vr0.max))
1920 || (vr1.type == VR_RANGE
1921 && integer_zerop (vr1.min)
1922 && integer_zerop (vr1.max))))
1925 min = max = build_int_cst (TREE_TYPE (expr), 0);
1927 /* If one of the operands is one, we know that the whole
1928 expression evaluates one. */
1929 else if (code == TRUTH_OR_EXPR
1930 && ((vr0.type == VR_RANGE
1931 && integer_onep (vr0.min)
1932 && integer_onep (vr0.max))
1933 || (vr1.type == VR_RANGE
1934 && integer_onep (vr1.min)
1935 && integer_onep (vr1.max))))
1938 min = max = build_int_cst (TREE_TYPE (expr), 1);
1940 else if (vr0.type != VR_VARYING
1941 && vr1.type != VR_VARYING
1942 && vr0.type == vr1.type
1943 && !symbolic_range_p (&vr0)
1944 && !overflow_infinity_range_p (&vr0)
1945 && !symbolic_range_p (&vr1)
1946 && !overflow_infinity_range_p (&vr1))
1948 /* Boolean expressions cannot be folded with int_const_binop. */
1949 min = fold_binary (code, TREE_TYPE (expr), vr0.min, vr1.min);
1950 max = fold_binary (code, TREE_TYPE (expr), vr0.max, vr1.max);
1954 /* The result of a TRUTH_*_EXPR is always true or false. */
1955 set_value_range_to_truthvalue (vr, TREE_TYPE (expr));
1959 else if (code == PLUS_EXPR
1961 || code == MAX_EXPR)
1963 /* If we have a PLUS_EXPR with two VR_ANTI_RANGEs, drop to
1964 VR_VARYING. It would take more effort to compute a precise
1965 range for such a case. For example, if we have op0 == 1 and
1966 op1 == -1 with their ranges both being ~[0,0], we would have
1967 op0 + op1 == 0, so we cannot claim that the sum is in ~[0,0].
1968 Note that we are guaranteed to have vr0.type == vr1.type at
1970 if (code == PLUS_EXPR && vr0.type == VR_ANTI_RANGE)
1972 set_value_range_to_varying (vr);
1976 /* For operations that make the resulting range directly
1977 proportional to the original ranges, apply the operation to
1978 the same end of each range. */
1979 min = vrp_int_const_binop (code, vr0.min, vr1.min);
1980 max = vrp_int_const_binop (code, vr0.max, vr1.max);
1982 else if (code == MULT_EXPR
1983 || code == TRUNC_DIV_EXPR
1984 || code == FLOOR_DIV_EXPR
1985 || code == CEIL_DIV_EXPR
1986 || code == EXACT_DIV_EXPR
1987 || code == ROUND_DIV_EXPR
1988 || code == RSHIFT_EXPR)
1994 /* If we have an unsigned MULT_EXPR with two VR_ANTI_RANGEs,
1995 drop to VR_VARYING. It would take more effort to compute a
1996 precise range for such a case. For example, if we have
1997 op0 == 65536 and op1 == 65536 with their ranges both being
1998 ~[0,0] on a 32-bit machine, we would have op0 * op1 == 0, so
1999 we cannot claim that the product is in ~[0,0]. Note that we
2000 are guaranteed to have vr0.type == vr1.type at this
2002 if (code == MULT_EXPR
2003 && vr0.type == VR_ANTI_RANGE
2004 && !TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (op0)))
2006 set_value_range_to_varying (vr);
2010 /* If we have a RSHIFT_EXPR with any shift values outside [0..prec-1],
2011 then drop to VR_VARYING. Outside of this range we get undefined
2012 behavior from the shift operation. We cannot even trust
2013 SHIFT_COUNT_TRUNCATED at this stage, because that applies to rtl
2014 shifts, and the operation at the tree level may be widened. */
2015 if (code == RSHIFT_EXPR)
2017 if (vr1.type == VR_ANTI_RANGE
2018 || !vrp_expr_computes_nonnegative (op1, &sop)
2020 (build_int_cst (TREE_TYPE (vr1.max),
2021 TYPE_PRECISION (TREE_TYPE (expr)) - 1),
2024 set_value_range_to_varying (vr);
2029 /* Multiplications and divisions are a bit tricky to handle,
2030 depending on the mix of signs we have in the two ranges, we
2031 need to operate on different values to get the minimum and
2032 maximum values for the new range. One approach is to figure
2033 out all the variations of range combinations and do the
2036 However, this involves several calls to compare_values and it
2037 is pretty convoluted. It's simpler to do the 4 operations
2038 (MIN0 OP MIN1, MIN0 OP MAX1, MAX0 OP MIN1 and MAX0 OP MAX0 OP
2039 MAX1) and then figure the smallest and largest values to form
2042 /* Divisions by zero result in a VARYING value. */
2043 else if (code != MULT_EXPR
2044 && (vr0.type == VR_ANTI_RANGE || range_includes_zero_p (&vr1)))
2046 set_value_range_to_varying (vr);
2050 /* Compute the 4 cross operations. */
2052 val[0] = vrp_int_const_binop (code, vr0.min, vr1.min);
2053 if (val[0] == NULL_TREE)
2056 if (vr1.max == vr1.min)
2060 val[1] = vrp_int_const_binop (code, vr0.min, vr1.max);
2061 if (val[1] == NULL_TREE)
2065 if (vr0.max == vr0.min)
2069 val[2] = vrp_int_const_binop (code, vr0.max, vr1.min);
2070 if (val[2] == NULL_TREE)
2074 if (vr0.min == vr0.max || vr1.min == vr1.max)
2078 val[3] = vrp_int_const_binop (code, vr0.max, vr1.max);
2079 if (val[3] == NULL_TREE)
2085 set_value_range_to_varying (vr);
2089 /* Set MIN to the minimum of VAL[i] and MAX to the maximum
2093 for (i = 1; i < 4; i++)
2095 if (!is_gimple_min_invariant (min)
2096 || (TREE_OVERFLOW (min) && !is_overflow_infinity (min))
2097 || !is_gimple_min_invariant (max)
2098 || (TREE_OVERFLOW (max) && !is_overflow_infinity (max)))
2103 if (!is_gimple_min_invariant (val[i])
2104 || (TREE_OVERFLOW (val[i])
2105 && !is_overflow_infinity (val[i])))
2107 /* If we found an overflowed value, set MIN and MAX
2108 to it so that we set the resulting range to
2114 if (compare_values (val[i], min) == -1)
2117 if (compare_values (val[i], max) == 1)
2122 else if (code == MINUS_EXPR)
2124 /* If we have a MINUS_EXPR with two VR_ANTI_RANGEs, drop to
2125 VR_VARYING. It would take more effort to compute a precise
2126 range for such a case. For example, if we have op0 == 1 and
2127 op1 == 1 with their ranges both being ~[0,0], we would have
2128 op0 - op1 == 0, so we cannot claim that the difference is in
2129 ~[0,0]. Note that we are guaranteed to have
2130 vr0.type == vr1.type at this point. */
2131 if (vr0.type == VR_ANTI_RANGE)
2133 set_value_range_to_varying (vr);
2137 /* For MINUS_EXPR, apply the operation to the opposite ends of
2139 min = vrp_int_const_binop (code, vr0.min, vr1.max);
2140 max = vrp_int_const_binop (code, vr0.max, vr1.min);
2142 else if (code == BIT_AND_EXPR)
2144 if (vr0.type == VR_RANGE
2145 && vr0.min == vr0.max
2146 && TREE_CODE (vr0.max) == INTEGER_CST
2147 && !TREE_OVERFLOW (vr0.max)
2148 && tree_int_cst_sgn (vr0.max) >= 0)
2150 min = build_int_cst (TREE_TYPE (expr), 0);
2153 else if (vr1.type == VR_RANGE
2154 && vr1.min == vr1.max
2155 && TREE_CODE (vr1.max) == INTEGER_CST
2156 && !TREE_OVERFLOW (vr1.max)
2157 && tree_int_cst_sgn (vr1.max) >= 0)
2160 min = build_int_cst (TREE_TYPE (expr), 0);
2165 set_value_range_to_varying (vr);
2172 /* If either MIN or MAX overflowed, then set the resulting range to
2173 VARYING. But we do accept an overflow infinity
2175 if (min == NULL_TREE
2176 || !is_gimple_min_invariant (min)
2177 || (TREE_OVERFLOW (min) && !is_overflow_infinity (min))
2179 || !is_gimple_min_invariant (max)
2180 || (TREE_OVERFLOW (max) && !is_overflow_infinity (max)))
2182 set_value_range_to_varying (vr);
2188 2) [-INF, +-INF(OVF)]
2189 3) [+-INF(OVF), +INF]
2190 4) [+-INF(OVF), +-INF(OVF)]
2191 We learn nothing when we have INF and INF(OVF) on both sides.
2192 Note that we do accept [-INF, -INF] and [+INF, +INF] without
2194 if ((vrp_val_is_min (min) || is_overflow_infinity (min))
2195 && (vrp_val_is_max (max) || is_overflow_infinity (max)))
2197 set_value_range_to_varying (vr);
2201 cmp = compare_values (min, max);
2202 if (cmp == -2 || cmp == 1)
2204 /* If the new range has its limits swapped around (MIN > MAX),
2205 then the operation caused one of them to wrap around, mark
2206 the new range VARYING. */
2207 set_value_range_to_varying (vr);
2210 set_value_range (vr, type, min, max, NULL);
2214 /* Extract range information from a unary expression EXPR based on
2215 the range of its operand and the expression code. */
2218 extract_range_from_unary_expr (value_range_t *vr, tree expr)
2220 enum tree_code code = TREE_CODE (expr);
2223 value_range_t vr0 = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
2225 /* Refuse to operate on certain unary expressions for which we
2226 cannot easily determine a resulting range. */
2227 if (code == FIX_TRUNC_EXPR
2228 || code == FLOAT_EXPR
2229 || code == BIT_NOT_EXPR
2230 || code == NON_LVALUE_EXPR
2231 || code == CONJ_EXPR)
2233 set_value_range_to_varying (vr);
2237 /* Get value ranges for the operand. For constant operands, create
2238 a new value range with the operand to simplify processing. */
2239 op0 = TREE_OPERAND (expr, 0);
2240 if (TREE_CODE (op0) == SSA_NAME)
2241 vr0 = *(get_value_range (op0));
2242 else if (is_gimple_min_invariant (op0))
2243 set_value_range_to_value (&vr0, op0, NULL);
2245 set_value_range_to_varying (&vr0);
2247 /* If VR0 is UNDEFINED, so is the result. */
2248 if (vr0.type == VR_UNDEFINED)
2250 set_value_range_to_undefined (vr);
2254 /* Refuse to operate on symbolic ranges, or if neither operand is
2255 a pointer or integral type. */
2256 if ((!INTEGRAL_TYPE_P (TREE_TYPE (op0))
2257 && !POINTER_TYPE_P (TREE_TYPE (op0)))
2258 || (vr0.type != VR_VARYING
2259 && symbolic_range_p (&vr0)))
2261 set_value_range_to_varying (vr);
2265 /* If the expression involves pointers, we are only interested in
2266 determining if it evaluates to NULL [0, 0] or non-NULL (~[0, 0]). */
2267 if (POINTER_TYPE_P (TREE_TYPE (expr)) || POINTER_TYPE_P (TREE_TYPE (op0)))
2272 if (range_is_nonnull (&vr0)
2273 || (tree_expr_nonzero_warnv_p (expr, &sop)
2275 set_value_range_to_nonnull (vr, TREE_TYPE (expr));
2276 else if (range_is_null (&vr0))
2277 set_value_range_to_null (vr, TREE_TYPE (expr));
2279 set_value_range_to_varying (vr);
2284 /* Handle unary expressions on integer ranges. */
2285 if (code == NOP_EXPR || code == CONVERT_EXPR)
2287 tree inner_type = TREE_TYPE (op0);
2288 tree outer_type = TREE_TYPE (expr);
2290 /* If VR0 represents a simple range, then try to convert
2291 the min and max values for the range to the same type
2292 as OUTER_TYPE. If the results compare equal to VR0's
2293 min and max values and the new min is still less than
2294 or equal to the new max, then we can safely use the newly
2295 computed range for EXPR. This allows us to compute
2296 accurate ranges through many casts. */
2297 if ((vr0.type == VR_RANGE
2298 && !overflow_infinity_range_p (&vr0))
2299 || (vr0.type == VR_VARYING
2300 && TYPE_PRECISION (outer_type) > TYPE_PRECISION (inner_type)))
2302 tree new_min, new_max, orig_min, orig_max;
2304 /* Convert the input operand min/max to OUTER_TYPE. If
2305 the input has no range information, then use the min/max
2306 for the input's type. */
2307 if (vr0.type == VR_RANGE)
2314 orig_min = TYPE_MIN_VALUE (inner_type);
2315 orig_max = TYPE_MAX_VALUE (inner_type);
2318 new_min = fold_convert (outer_type, orig_min);
2319 new_max = fold_convert (outer_type, orig_max);
2321 /* Verify the new min/max values are gimple values and
2322 that they compare equal to the original input's
2324 if (is_gimple_val (new_min)
2325 && is_gimple_val (new_max)
2326 && tree_int_cst_equal (new_min, orig_min)
2327 && tree_int_cst_equal (new_max, orig_max)
2328 && (!is_overflow_infinity (new_min)
2329 || !is_overflow_infinity (new_max))
2330 && (cmp = compare_values (new_min, new_max)) <= 0
2333 set_value_range (vr, VR_RANGE, new_min, new_max, vr->equiv);
2338 /* When converting types of different sizes, set the result to
2339 VARYING. Things like sign extensions and precision loss may
2340 change the range. For instance, if x_3 is of type 'long long
2341 int' and 'y_5 = (unsigned short) x_3', if x_3 is ~[0, 0], it
2342 is impossible to know at compile time whether y_5 will be
2344 if (TYPE_SIZE (inner_type) != TYPE_SIZE (outer_type)
2345 || TYPE_PRECISION (inner_type) != TYPE_PRECISION (outer_type))
2347 set_value_range_to_varying (vr);
2352 /* Conversion of a VR_VARYING value to a wider type can result
2353 in a usable range. So wait until after we've handled conversions
2354 before dropping the result to VR_VARYING if we had a source
2355 operand that is VR_VARYING. */
2356 if (vr0.type == VR_VARYING)
2358 set_value_range_to_varying (vr);
2362 /* Apply the operation to each end of the range and see what we end
2364 if (code == NEGATE_EXPR
2365 && !TYPE_UNSIGNED (TREE_TYPE (expr)))
2367 /* NEGATE_EXPR flips the range around. We need to treat
2368 TYPE_MIN_VALUE specially. */
2369 if (is_positive_overflow_infinity (vr0.max))
2370 min = negative_overflow_infinity (TREE_TYPE (expr));
2371 else if (is_negative_overflow_infinity (vr0.max))
2372 min = positive_overflow_infinity (TREE_TYPE (expr));
2373 else if (!vrp_val_is_min (vr0.max))
2374 min = fold_unary_to_constant (code, TREE_TYPE (expr), vr0.max);
2375 else if (needs_overflow_infinity (TREE_TYPE (expr)))
2377 if (supports_overflow_infinity (TREE_TYPE (expr))
2378 && !is_overflow_infinity (vr0.min)
2379 && !vrp_val_is_min (vr0.min))
2380 min = positive_overflow_infinity (TREE_TYPE (expr));
2383 set_value_range_to_varying (vr);
2388 min = TYPE_MIN_VALUE (TREE_TYPE (expr));
2390 if (is_positive_overflow_infinity (vr0.min))
2391 max = negative_overflow_infinity (TREE_TYPE (expr));
2392 else if (is_negative_overflow_infinity (vr0.min))
2393 max = positive_overflow_infinity (TREE_TYPE (expr));
2394 else if (!vrp_val_is_min (vr0.min))
2395 max = fold_unary_to_constant (code, TREE_TYPE (expr), vr0.min);
2396 else if (needs_overflow_infinity (TREE_TYPE (expr)))
2398 if (supports_overflow_infinity (TREE_TYPE (expr)))
2399 max = positive_overflow_infinity (TREE_TYPE (expr));
2402 set_value_range_to_varying (vr);
2407 max = TYPE_MIN_VALUE (TREE_TYPE (expr));
2409 else if (code == NEGATE_EXPR
2410 && TYPE_UNSIGNED (TREE_TYPE (expr)))
2412 if (!range_includes_zero_p (&vr0))
2414 max = fold_unary_to_constant (code, TREE_TYPE (expr), vr0.min);
2415 min = fold_unary_to_constant (code, TREE_TYPE (expr), vr0.max);
2419 if (range_is_null (&vr0))
2420 set_value_range_to_null (vr, TREE_TYPE (expr));
2422 set_value_range_to_varying (vr);
2426 else if (code == ABS_EXPR
2427 && !TYPE_UNSIGNED (TREE_TYPE (expr)))
2429 /* -TYPE_MIN_VALUE = TYPE_MIN_VALUE with flag_wrapv so we can't get a
2431 if (!TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (expr))
2432 && ((vr0.type == VR_RANGE
2433 && vrp_val_is_min (vr0.min))
2434 || (vr0.type == VR_ANTI_RANGE
2435 && !vrp_val_is_min (vr0.min)
2436 && !range_includes_zero_p (&vr0))))
2438 set_value_range_to_varying (vr);
2442 /* ABS_EXPR may flip the range around, if the original range
2443 included negative values. */
2444 if (is_overflow_infinity (vr0.min))
2445 min = positive_overflow_infinity (TREE_TYPE (expr));
2446 else if (!vrp_val_is_min (vr0.min))
2447 min = fold_unary_to_constant (code, TREE_TYPE (expr), vr0.min);
2448 else if (!needs_overflow_infinity (TREE_TYPE (expr)))
2449 min = TYPE_MAX_VALUE (TREE_TYPE (expr));
2450 else if (supports_overflow_infinity (TREE_TYPE (expr)))
2451 min = positive_overflow_infinity (TREE_TYPE (expr));
2454 set_value_range_to_varying (vr);
2458 if (is_overflow_infinity (vr0.max))
2459 max = positive_overflow_infinity (TREE_TYPE (expr));
2460 else if (!vrp_val_is_min (vr0.max))
2461 max = fold_unary_to_constant (code, TREE_TYPE (expr), vr0.max);
2462 else if (!needs_overflow_infinity (TREE_TYPE (expr)))
2463 max = TYPE_MAX_VALUE (TREE_TYPE (expr));
2464 else if (supports_overflow_infinity (TREE_TYPE (expr)))
2465 max = positive_overflow_infinity (TREE_TYPE (expr));
2468 set_value_range_to_varying (vr);
2472 cmp = compare_values (min, max);
2474 /* If a VR_ANTI_RANGEs contains zero, then we have
2475 ~[-INF, min(MIN, MAX)]. */
2476 if (vr0.type == VR_ANTI_RANGE)
2478 if (range_includes_zero_p (&vr0))
2480 /* Take the lower of the two values. */
2484 /* Create ~[-INF, min (abs(MIN), abs(MAX))]
2485 or ~[-INF + 1, min (abs(MIN), abs(MAX))] when
2486 flag_wrapv is set and the original anti-range doesn't include
2487 TYPE_MIN_VALUE, remember -TYPE_MIN_VALUE = TYPE_MIN_VALUE. */
2488 if (TYPE_OVERFLOW_WRAPS (TREE_TYPE (expr)))
2490 tree type_min_value = TYPE_MIN_VALUE (TREE_TYPE (expr));
2492 min = (vr0.min != type_min_value
2493 ? int_const_binop (PLUS_EXPR, type_min_value,
2494 integer_one_node, 0)
2499 if (overflow_infinity_range_p (&vr0))
2500 min = negative_overflow_infinity (TREE_TYPE (expr));
2502 min = TYPE_MIN_VALUE (TREE_TYPE (expr));
2507 /* All else has failed, so create the range [0, INF], even for
2508 flag_wrapv since TYPE_MIN_VALUE is in the original
2510 vr0.type = VR_RANGE;
2511 min = build_int_cst (TREE_TYPE (expr), 0);
2512 if (needs_overflow_infinity (TREE_TYPE (expr)))
2514 if (supports_overflow_infinity (TREE_TYPE (expr)))
2515 max = positive_overflow_infinity (TREE_TYPE (expr));
2518 set_value_range_to_varying (vr);
2523 max = TYPE_MAX_VALUE (TREE_TYPE (expr));
2527 /* If the range contains zero then we know that the minimum value in the
2528 range will be zero. */
2529 else if (range_includes_zero_p (&vr0))
2533 min = build_int_cst (TREE_TYPE (expr), 0);
2537 /* If the range was reversed, swap MIN and MAX. */
2548 /* Otherwise, operate on each end of the range. */
2549 min = fold_unary_to_constant (code, TREE_TYPE (expr), vr0.min);
2550 max = fold_unary_to_constant (code, TREE_TYPE (expr), vr0.max);
2552 if (needs_overflow_infinity (TREE_TYPE (expr)))
2554 gcc_assert (code != NEGATE_EXPR && code != ABS_EXPR);
2556 /* If both sides have overflowed, we don't know
2558 if ((is_overflow_infinity (vr0.min)
2559 || TREE_OVERFLOW (min))
2560 && (is_overflow_infinity (vr0.max)
2561 || TREE_OVERFLOW (max)))
2563 set_value_range_to_varying (vr);
2567 if (is_overflow_infinity (vr0.min))
2569 else if (TREE_OVERFLOW (min))
2571 if (supports_overflow_infinity (TREE_TYPE (expr)))
2572 min = (tree_int_cst_sgn (min) >= 0
2573 ? positive_overflow_infinity (TREE_TYPE (min))
2574 : negative_overflow_infinity (TREE_TYPE (min)));
2577 set_value_range_to_varying (vr);
2582 if (is_overflow_infinity (vr0.max))
2584 else if (TREE_OVERFLOW (max))
2586 if (supports_overflow_infinity (TREE_TYPE (expr)))
2587 max = (tree_int_cst_sgn (max) >= 0
2588 ? positive_overflow_infinity (TREE_TYPE (max))
2589 : negative_overflow_infinity (TREE_TYPE (max)));
2592 set_value_range_to_varying (vr);
2599 cmp = compare_values (min, max);
2600 if (cmp == -2 || cmp == 1)
2602 /* If the new range has its limits swapped around (MIN > MAX),
2603 then the operation caused one of them to wrap around, mark
2604 the new range VARYING. */
2605 set_value_range_to_varying (vr);
2608 set_value_range (vr, vr0.type, min, max, NULL);
2612 /* Extract range information from a conditional expression EXPR based on
2613 the ranges of each of its operands and the expression code. */
2616 extract_range_from_cond_expr (value_range_t *vr, tree expr)
2619 value_range_t vr0 = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
2620 value_range_t vr1 = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
2622 /* Get value ranges for each operand. For constant operands, create
2623 a new value range with the operand to simplify processing. */
2624 op0 = COND_EXPR_THEN (expr);
2625 if (TREE_CODE (op0) == SSA_NAME)
2626 vr0 = *(get_value_range (op0));
2627 else if (is_gimple_min_invariant (op0))
2628 set_value_range_to_value (&vr0, op0, NULL);
2630 set_value_range_to_varying (&vr0);
2632 op1 = COND_EXPR_ELSE (expr);
2633 if (TREE_CODE (op1) == SSA_NAME)
2634 vr1 = *(get_value_range (op1));
2635 else if (is_gimple_min_invariant (op1))
2636 set_value_range_to_value (&vr1, op1, NULL);
2638 set_value_range_to_varying (&vr1);
2640 /* The resulting value range is the union of the operand ranges */
2641 vrp_meet (&vr0, &vr1);
2642 copy_value_range (vr, &vr0);
2646 /* Extract range information from a comparison expression EXPR based
2647 on the range of its operand and the expression code. */
2650 extract_range_from_comparison (value_range_t *vr, tree expr)
2653 tree val = vrp_evaluate_conditional_warnv (expr, false, &sop);
2655 /* A disadvantage of using a special infinity as an overflow
2656 representation is that we lose the ability to record overflow
2657 when we don't have an infinity. So we have to ignore a result
2658 which relies on overflow. */
2660 if (val && !is_overflow_infinity (val) && !sop)
2662 /* Since this expression was found on the RHS of an assignment,
2663 its type may be different from _Bool. Convert VAL to EXPR's
2665 val = fold_convert (TREE_TYPE (expr), val);
2666 if (is_gimple_min_invariant (val))
2667 set_value_range_to_value (vr, val, vr->equiv);
2669 set_value_range (vr, VR_RANGE, val, val, vr->equiv);
2672 /* The result of a comparison is always true or false. */
2673 set_value_range_to_truthvalue (vr, TREE_TYPE (expr));
2677 /* Try to compute a useful range out of expression EXPR and store it
2681 extract_range_from_expr (value_range_t *vr, tree expr)
2683 enum tree_code code = TREE_CODE (expr);
2685 if (code == ASSERT_EXPR)
2686 extract_range_from_assert (vr, expr);
2687 else if (code == SSA_NAME)
2688 extract_range_from_ssa_name (vr, expr);
2689 else if (TREE_CODE_CLASS (code) == tcc_binary
2690 || code == TRUTH_ANDIF_EXPR
2691 || code == TRUTH_ORIF_EXPR
2692 || code == TRUTH_AND_EXPR
2693 || code == TRUTH_OR_EXPR
2694 || code == TRUTH_XOR_EXPR)
2695 extract_range_from_binary_expr (vr, expr);
2696 else if (TREE_CODE_CLASS (code) == tcc_unary)
2697 extract_range_from_unary_expr (vr, expr);
2698 else if (code == COND_EXPR)
2699 extract_range_from_cond_expr (vr, expr);
2700 else if (TREE_CODE_CLASS (code) == tcc_comparison)
2701 extract_range_from_comparison (vr, expr);
2702 else if (is_gimple_min_invariant (expr))
2703 set_value_range_to_value (vr, expr, NULL);
2705 set_value_range_to_varying (vr);
2707 /* If we got a varying range from the tests above, try a final
2708 time to derive a nonnegative or nonzero range. This time
2709 relying primarily on generic routines in fold in conjunction
2711 if (vr->type == VR_VARYING)
2715 if (INTEGRAL_TYPE_P (TREE_TYPE (expr))
2716 && vrp_expr_computes_nonnegative (expr, &sop))
2717 set_value_range_to_nonnegative (vr, TREE_TYPE (expr),
2718 sop || is_overflow_infinity (expr));
2719 else if (vrp_expr_computes_nonzero (expr, &sop)
2721 set_value_range_to_nonnull (vr, TREE_TYPE (expr));
2725 /* Given a range VR, a LOOP and a variable VAR, determine whether it
2726 would be profitable to adjust VR using scalar evolution information
2727 for VAR. If so, update VR with the new limits. */
2730 adjust_range_with_scev (value_range_t *vr, struct loop *loop, tree stmt,
2733 tree init, step, chrec, tmin, tmax, min, max, type;
2734 enum ev_direction dir;
2736 /* TODO. Don't adjust anti-ranges. An anti-range may provide
2737 better opportunities than a regular range, but I'm not sure. */
2738 if (vr->type == VR_ANTI_RANGE)
2741 /* Ensure that there are not values in the scev cache based on assumptions
2742 on ranges of ssa names that were changed
2743 (in set_value_range/set_value_range_to_varying). Preserve cached numbers
2744 of iterations, that were computed before the start of VRP (we do not
2745 recompute these each time to save the compile time). */
2746 scev_reset_except_niters ();
2748 chrec = instantiate_parameters (loop, analyze_scalar_evolution (loop, var));
2750 /* Like in PR19590, scev can return a constant function. */
2751 if (is_gimple_min_invariant (chrec))
2753 set_value_range_to_value (vr, chrec, vr->equiv);
2757 if (TREE_CODE (chrec) != POLYNOMIAL_CHREC)
2760 init = initial_condition_in_loop_num (chrec, loop->num);
2761 step = evolution_part_in_loop_num (chrec, loop->num);
2763 /* If STEP is symbolic, we can't know whether INIT will be the
2764 minimum or maximum value in the range. Also, unless INIT is
2765 a simple expression, compare_values and possibly other functions
2766 in tree-vrp won't be able to handle it. */
2767 if (step == NULL_TREE
2768 || !is_gimple_min_invariant (step)
2769 || !valid_value_p (init))
2772 dir = scev_direction (chrec);
2773 if (/* Do not adjust ranges if we do not know whether the iv increases
2774 or decreases, ... */
2775 dir == EV_DIR_UNKNOWN
2776 /* ... or if it may wrap. */
2777 || scev_probably_wraps_p (init, step, stmt, get_chrec_loop (chrec),
2781 /* We use TYPE_MIN_VALUE and TYPE_MAX_VALUE here instead of
2782 negative_overflow_infinity and positive_overflow_infinity,
2783 because we have concluded that the loop probably does not
2786 type = TREE_TYPE (var);
2787 if (POINTER_TYPE_P (type) || !TYPE_MIN_VALUE (type))
2788 tmin = lower_bound_in_type (type, type);
2790 tmin = TYPE_MIN_VALUE (type);
2791 if (POINTER_TYPE_P (type) || !TYPE_MAX_VALUE (type))
2792 tmax = upper_bound_in_type (type, type);
2794 tmax = TYPE_MAX_VALUE (type);
2796 if (vr->type == VR_VARYING || vr->type == VR_UNDEFINED)
2801 /* For VARYING or UNDEFINED ranges, just about anything we get
2802 from scalar evolutions should be better. */
2804 if (dir == EV_DIR_DECREASES)
2809 /* If we would create an invalid range, then just assume we
2810 know absolutely nothing. This may be over-conservative,
2811 but it's clearly safe, and should happen only in unreachable
2812 parts of code, or for invalid programs. */
2813 if (compare_values (min, max) == 1)
2816 set_value_range (vr, VR_RANGE, min, max, vr->equiv);
2818 else if (vr->type == VR_RANGE)
2823 if (dir == EV_DIR_DECREASES)
2825 /* INIT is the maximum value. If INIT is lower than VR->MAX
2826 but no smaller than VR->MIN, set VR->MAX to INIT. */
2827 if (compare_values (init, max) == -1)
2831 /* If we just created an invalid range with the minimum
2832 greater than the maximum, we fail conservatively.
2833 This should happen only in unreachable
2834 parts of code, or for invalid programs. */
2835 if (compare_values (min, max) == 1)
2839 /* According to the loop information, the variable does not
2840 overflow. If we think it does, probably because of an
2841 overflow due to arithmetic on a different INF value,
2843 if (is_negative_overflow_infinity (min))
2848 /* If INIT is bigger than VR->MIN, set VR->MIN to INIT. */
2849 if (compare_values (init, min) == 1)
2853 /* Again, avoid creating invalid range by failing. */
2854 if (compare_values (min, max) == 1)
2858 if (is_positive_overflow_infinity (max))
2862 set_value_range (vr, VR_RANGE, min, max, vr->equiv);
2866 /* Return true if VAR may overflow at STMT. This checks any available
2867 loop information to see if we can determine that VAR does not
2871 vrp_var_may_overflow (tree var, tree stmt)
2874 tree chrec, init, step;
2876 if (current_loops == NULL)
2879 l = loop_containing_stmt (stmt);
2883 chrec = instantiate_parameters (l, analyze_scalar_evolution (l, var));
2884 if (TREE_CODE (chrec) != POLYNOMIAL_CHREC)
2887 init = initial_condition_in_loop_num (chrec, l->num);
2888 step = evolution_part_in_loop_num (chrec, l->num);
2890 if (step == NULL_TREE
2891 || !is_gimple_min_invariant (step)
2892 || !valid_value_p (init))
2895 /* If we get here, we know something useful about VAR based on the
2896 loop information. If it wraps, it may overflow. */
2898 if (scev_probably_wraps_p (init, step, stmt, get_chrec_loop (chrec),
2902 if (dump_file && (dump_flags & TDF_DETAILS) != 0)
2904 print_generic_expr (dump_file, var, 0);
2905 fprintf (dump_file, ": loop information indicates does not overflow\n");
2912 /* Given two numeric value ranges VR0, VR1 and a comparison code COMP:
2914 - Return BOOLEAN_TRUE_NODE if VR0 COMP VR1 always returns true for
2915 all the values in the ranges.
2917 - Return BOOLEAN_FALSE_NODE if the comparison always returns false.
2919 - Return NULL_TREE if it is not always possible to determine the
2920 value of the comparison.
2922 Also set *STRICT_OVERFLOW_P to indicate whether a range with an
2923 overflow infinity was used in the test. */
2927 compare_ranges (enum tree_code comp, value_range_t *vr0, value_range_t *vr1,
2928 bool *strict_overflow_p)
2930 /* VARYING or UNDEFINED ranges cannot be compared. */
2931 if (vr0->type == VR_VARYING
2932 || vr0->type == VR_UNDEFINED
2933 || vr1->type == VR_VARYING
2934 || vr1->type == VR_UNDEFINED)
2937 /* Anti-ranges need to be handled separately. */
2938 if (vr0->type == VR_ANTI_RANGE || vr1->type == VR_ANTI_RANGE)
2940 /* If both are anti-ranges, then we cannot compute any
2942 if (vr0->type == VR_ANTI_RANGE && vr1->type == VR_ANTI_RANGE)
2945 /* These comparisons are never statically computable. */
2952 /* Equality can be computed only between a range and an
2953 anti-range. ~[VAL1, VAL2] == [VAL1, VAL2] is always false. */
2954 if (vr0->type == VR_RANGE)
2956 /* To simplify processing, make VR0 the anti-range. */
2957 value_range_t *tmp = vr0;
2962 gcc_assert (comp == NE_EXPR || comp == EQ_EXPR);
2964 if (compare_values_warnv (vr0->min, vr1->min, strict_overflow_p) == 0
2965 && compare_values_warnv (vr0->max, vr1->max, strict_overflow_p) == 0)
2966 return (comp == NE_EXPR) ? boolean_true_node : boolean_false_node;
2971 if (!usable_range_p (vr0, strict_overflow_p)
2972 || !usable_range_p (vr1, strict_overflow_p))
2975 /* Simplify processing. If COMP is GT_EXPR or GE_EXPR, switch the
2976 operands around and change the comparison code. */
2977 if (comp == GT_EXPR || comp == GE_EXPR)
2980 comp = (comp == GT_EXPR) ? LT_EXPR : LE_EXPR;
2986 if (comp == EQ_EXPR)
2988 /* Equality may only be computed if both ranges represent
2989 exactly one value. */
2990 if (compare_values_warnv (vr0->min, vr0->max, strict_overflow_p) == 0
2991 && compare_values_warnv (vr1->min, vr1->max, strict_overflow_p) == 0)
2993 int cmp_min = compare_values_warnv (vr0->min, vr1->min,
2995 int cmp_max = compare_values_warnv (vr0->max, vr1->max,
2997 if (cmp_min == 0 && cmp_max == 0)
2998 return boolean_true_node;
2999 else if (cmp_min != -2 && cmp_max != -2)
3000 return boolean_false_node;
3002 /* If [V0_MIN, V1_MAX] < [V1_MIN, V1_MAX] then V0 != V1. */
3003 else if (compare_values_warnv (vr0->min, vr1->max,
3004 strict_overflow_p) == 1
3005 || compare_values_warnv (vr1->min, vr0->max,
3006 strict_overflow_p) == 1)
3007 return boolean_false_node;
3011 else if (comp == NE_EXPR)
3015 /* If VR0 is completely to the left or completely to the right
3016 of VR1, they are always different. Notice that we need to
3017 make sure that both comparisons yield similar results to
3018 avoid comparing values that cannot be compared at
3020 cmp1 = compare_values_warnv (vr0->max, vr1->min, strict_overflow_p);
3021 cmp2 = compare_values_warnv (vr0->min, vr1->max, strict_overflow_p);
3022 if ((cmp1 == -1 && cmp2 == -1) || (cmp1 == 1 && cmp2 == 1))
3023 return boolean_true_node;
3025 /* If VR0 and VR1 represent a single value and are identical,
3027 else if (compare_values_warnv (vr0->min, vr0->max,
3028 strict_overflow_p) == 0
3029 && compare_values_warnv (vr1->min, vr1->max,
3030 strict_overflow_p) == 0
3031 && compare_values_warnv (vr0->min, vr1->min,
3032 strict_overflow_p) == 0
3033 && compare_values_warnv (vr0->max, vr1->max,
3034 strict_overflow_p) == 0)
3035 return boolean_false_node;
3037 /* Otherwise, they may or may not be different. */
3041 else if (comp == LT_EXPR || comp == LE_EXPR)
3045 /* If VR0 is to the left of VR1, return true. */
3046 tst = compare_values_warnv (vr0->max, vr1->min, strict_overflow_p);
3047 if ((comp == LT_EXPR && tst == -1)
3048 || (comp == LE_EXPR && (tst == -1 || tst == 0)))
3050 if (overflow_infinity_range_p (vr0)
3051 || overflow_infinity_range_p (vr1))
3052 *strict_overflow_p = true;
3053 return boolean_true_node;
3056 /* If VR0 is to the right of VR1, return false. */
3057 tst = compare_values_warnv (vr0->min, vr1->max, strict_overflow_p);
3058 if ((comp == LT_EXPR && (tst == 0 || tst == 1))
3059 || (comp == LE_EXPR && tst == 1))
3061 if (overflow_infinity_range_p (vr0)
3062 || overflow_infinity_range_p (vr1))
3063 *strict_overflow_p = true;
3064 return boolean_false_node;
3067 /* Otherwise, we don't know. */
3075 /* Given a value range VR, a value VAL and a comparison code COMP, return
3076 BOOLEAN_TRUE_NODE if VR COMP VAL always returns true for all the
3077 values in VR. Return BOOLEAN_FALSE_NODE if the comparison
3078 always returns false. Return NULL_TREE if it is not always
3079 possible to determine the value of the comparison. Also set
3080 *STRICT_OVERFLOW_P to indicate whether a range with an overflow
3081 infinity was used in the test. */
3084 compare_range_with_value (enum tree_code comp, value_range_t *vr, tree val,
3085 bool *strict_overflow_p)
3087 if (vr->type == VR_VARYING || vr->type == VR_UNDEFINED)
3090 /* Anti-ranges need to be handled separately. */
3091 if (vr->type == VR_ANTI_RANGE)
3093 /* For anti-ranges, the only predicates that we can compute at
3094 compile time are equality and inequality. */
3101 /* ~[VAL_1, VAL_2] OP VAL is known if VAL_1 <= VAL <= VAL_2. */
3102 if (value_inside_range (val, vr) == 1)
3103 return (comp == NE_EXPR) ? boolean_true_node : boolean_false_node;
3108 if (!usable_range_p (vr, strict_overflow_p))
3111 if (comp == EQ_EXPR)
3113 /* EQ_EXPR may only be computed if VR represents exactly
3115 if (compare_values_warnv (vr->min, vr->max, strict_overflow_p) == 0)
3117 int cmp = compare_values_warnv (vr->min, val, strict_overflow_p);
3119 return boolean_true_node;
3120 else if (cmp == -1 || cmp == 1 || cmp == 2)
3121 return boolean_false_node;
3123 else if (compare_values_warnv (val, vr->min, strict_overflow_p) == -1
3124 || compare_values_warnv (vr->max, val, strict_overflow_p) == -1)
3125 return boolean_false_node;
3129 else if (comp == NE_EXPR)
3131 /* If VAL is not inside VR, then they are always different. */
3132 if (compare_values_warnv (vr->max, val, strict_overflow_p) == -1
3133 || compare_values_warnv (vr->min, val, strict_overflow_p) == 1)
3134 return boolean_true_node;
3136 /* If VR represents exactly one value equal to VAL, then return
3138 if (compare_values_warnv (vr->min, vr->max, strict_overflow_p) == 0
3139 && compare_values_warnv (vr->min, val, strict_overflow_p) == 0)
3140 return boolean_false_node;
3142 /* Otherwise, they may or may not be different. */
3145 else if (comp == LT_EXPR || comp == LE_EXPR)
3149 /* If VR is to the left of VAL, return true. */
3150 tst = compare_values_warnv (vr->max, val, strict_overflow_p);
3151 if ((comp == LT_EXPR && tst == -1)
3152 || (comp == LE_EXPR && (tst == -1 || tst == 0)))
3154 if (overflow_infinity_range_p (vr))
3155 *strict_overflow_p = true;
3156 return boolean_true_node;
3159 /* If VR is to the right of VAL, return false. */
3160 tst = compare_values_warnv (vr->min, val, strict_overflow_p);
3161 if ((comp == LT_EXPR && (tst == 0 || tst == 1))
3162 || (comp == LE_EXPR && tst == 1))
3164 if (overflow_infinity_range_p (vr))
3165 *strict_overflow_p = true;
3166 return boolean_false_node;
3169 /* Otherwise, we don't know. */
3172 else if (comp == GT_EXPR || comp == GE_EXPR)
3176 /* If VR is to the right of VAL, return true. */
3177 tst = compare_values_warnv (vr->min, val, strict_overflow_p);
3178 if ((comp == GT_EXPR && tst == 1)
3179 || (comp == GE_EXPR && (tst == 0 || tst == 1)))
3181 if (overflow_infinity_range_p (vr))
3182 *strict_overflow_p = true;
3183 return boolean_true_node;
3186 /* If VR is to the left of VAL, return false. */
3187 tst = compare_values_warnv (vr->max, val, strict_overflow_p);
3188 if ((comp == GT_EXPR && (tst == -1 || tst == 0))
3189 || (comp == GE_EXPR && tst == -1))
3191 if (overflow_infinity_range_p (vr))
3192 *strict_overflow_p = true;
3193 return boolean_false_node;
3196 /* Otherwise, we don't know. */
3204 /* Debugging dumps. */
3206 void dump_value_range (FILE *, value_range_t *);
3207 void debug_value_range (value_range_t *);
3208 void dump_all_value_ranges (FILE *);
3209 void debug_all_value_ranges (void);
3210 void dump_vr_equiv (FILE *, bitmap);
3211 void debug_vr_equiv (bitmap);
3214 /* Dump value range VR to FILE. */
3217 dump_value_range (FILE *file, value_range_t *vr)
3220 fprintf (file, "[]");
3221 else if (vr->type == VR_UNDEFINED)
3222 fprintf (file, "UNDEFINED");
3223 else if (vr->type == VR_RANGE || vr->type == VR_ANTI_RANGE)
3225 tree type = TREE_TYPE (vr->min);
3227 fprintf (file, "%s[", (vr->type == VR_ANTI_RANGE) ? "~" : "");
3229 if (is_negative_overflow_infinity (vr->min))
3230 fprintf (file, "-INF(OVF)");
3231 else if (INTEGRAL_TYPE_P (type)
3232 && !TYPE_UNSIGNED (type)
3233 && vrp_val_is_min (vr->min))
3234 fprintf (file, "-INF");
3236 print_generic_expr (file, vr->min, 0);
3238 fprintf (file, ", ");
3240 if (is_positive_overflow_infinity (vr->max))
3241 fprintf (file, "+INF(OVF)");
3242 else if (INTEGRAL_TYPE_P (type)
3243 && vrp_val_is_max (vr->max))
3244 fprintf (file, "+INF");
3246 print_generic_expr (file, vr->max, 0);
3248 fprintf (file, "]");
3255 fprintf (file, " EQUIVALENCES: { ");
3257 EXECUTE_IF_SET_IN_BITMAP (vr->equiv, 0, i, bi)
3259 print_generic_expr (file, ssa_name (i), 0);
3260 fprintf (file, " ");
3264 fprintf (file, "} (%u elements)", c);
3267 else if (vr->type == VR_VARYING)
3268 fprintf (file, "VARYING");
3270 fprintf (file, "INVALID RANGE");
3274 /* Dump value range VR to stderr. */
3277 debug_value_range (value_range_t *vr)
3279 dump_value_range (stderr, vr);
3280 fprintf (stderr, "\n");
3284 /* Dump value ranges of all SSA_NAMEs to FILE. */
3287 dump_all_value_ranges (FILE *file)
3291 for (i = 0; i < num_ssa_names; i++)
3295 print_generic_expr (file, ssa_name (i), 0);
3296 fprintf (file, ": ");
3297 dump_value_range (file, vr_value[i]);
3298 fprintf (file, "\n");
3302 fprintf (file, "\n");
3306 /* Dump all value ranges to stderr. */
3309 debug_all_value_ranges (void)
3311 dump_all_value_ranges (stderr);
3315 /* Given a COND_EXPR COND of the form 'V OP W', and an SSA name V,
3316 create a new SSA name N and return the assertion assignment
3317 'V = ASSERT_EXPR <V, V OP W>'. */
3320 build_assert_expr_for (tree cond, tree v)
3324 gcc_assert (TREE_CODE (v) == SSA_NAME);
3325 n = duplicate_ssa_name (v, NULL_TREE);
3327 if (COMPARISON_CLASS_P (cond))
3329 tree a = build2 (ASSERT_EXPR, TREE_TYPE (v), v, cond);
3330 assertion = build_gimple_modify_stmt (n, a);
3332 else if (TREE_CODE (cond) == TRUTH_NOT_EXPR)
3334 /* Given !V, build the assignment N = false. */
3335 tree op0 = TREE_OPERAND (cond, 0);
3336 gcc_assert (op0 == v);
3337 assertion = build_gimple_modify_stmt (n, boolean_false_node);
3339 else if (TREE_CODE (cond) == SSA_NAME)
3341 /* Given V, build the assignment N = true. */
3342 gcc_assert (v == cond);
3343 assertion = build_gimple_modify_stmt (n, boolean_true_node);
3348 SSA_NAME_DEF_STMT (n) = assertion;
3350 /* The new ASSERT_EXPR, creates a new SSA name that replaces the
3351 operand of the ASSERT_EXPR. Register the new name and the old one
3352 in the replacement table so that we can fix the SSA web after
3353 adding all the ASSERT_EXPRs. */
3354 register_new_name_mapping (n, v);
3360 /* Return false if EXPR is a predicate expression involving floating
3364 fp_predicate (const_tree expr)
3366 return (COMPARISON_CLASS_P (expr)
3367 && FLOAT_TYPE_P (TREE_TYPE (TREE_OPERAND (expr, 0))));
3371 /* If the range of values taken by OP can be inferred after STMT executes,
3372 return the comparison code (COMP_CODE_P) and value (VAL_P) that
3373 describes the inferred range. Return true if a range could be
3377 infer_value_range (tree stmt, tree op, enum tree_code *comp_code_p, tree *val_p)
3380 *comp_code_p = ERROR_MARK;
3382 /* Do not attempt to infer anything in names that flow through
3384 if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (op))
3387 /* Similarly, don't infer anything from statements that may throw
3389 if (tree_could_throw_p (stmt))
3392 /* If STMT is the last statement of a basic block with no
3393 successors, there is no point inferring anything about any of its
3394 operands. We would not be able to find a proper insertion point
3395 for the assertion, anyway. */
3396 if (stmt_ends_bb_p (stmt) && EDGE_COUNT (bb_for_stmt (stmt)->succs) == 0)
3399 /* We can only assume that a pointer dereference will yield
3400 non-NULL if -fdelete-null-pointer-checks is enabled. */
3401 if (flag_delete_null_pointer_checks && POINTER_TYPE_P (TREE_TYPE (op)))
3403 unsigned num_uses, num_loads, num_stores;
3405 count_uses_and_derefs (op, stmt, &num_uses, &num_loads, &num_stores);
3406 if (num_loads + num_stores > 0)
3408 *val_p = build_int_cst (TREE_TYPE (op), 0);
3409 *comp_code_p = NE_EXPR;
3418 void dump_asserts_for (FILE *, tree);
3419 void debug_asserts_for (tree);
3420 void dump_all_asserts (FILE *);
3421 void debug_all_asserts (void);
3423 /* Dump all the registered assertions for NAME to FILE. */
3426 dump_asserts_for (FILE *file, tree name)
3430 fprintf (file, "Assertions to be inserted for ");
3431 print_generic_expr (file, name, 0);
3432 fprintf (file, "\n");
3434 loc = asserts_for[SSA_NAME_VERSION (name)];
3437 fprintf (file, "\t");
3438 print_generic_expr (file, bsi_stmt (loc->si), 0);
3439 fprintf (file, "\n\tBB #%d", loc->bb->index);
3442 fprintf (file, "\n\tEDGE %d->%d", loc->e->src->index,
3443 loc->e->dest->index);
3444 dump_edge_info (file, loc->e, 0);
3446 fprintf (file, "\n\tPREDICATE: ");
3447 print_generic_expr (file, name, 0);
3448 fprintf (file, " %s ", tree_code_name[(int)loc->comp_code]);
3449 print_generic_expr (file, loc->val, 0);
3450 fprintf (file, "\n\n");
3454 fprintf (file, "\n");
3458 /* Dump all the registered assertions for NAME to stderr. */
3461 debug_asserts_for (tree name)
3463 dump_asserts_for (stderr, name);
3467 /* Dump all the registered assertions for all the names to FILE. */
3470 dump_all_asserts (FILE *file)
3475 fprintf (file, "\nASSERT_EXPRs to be inserted\n\n");
3476 EXECUTE_IF_SET_IN_BITMAP (need_assert_for, 0, i, bi)
3477 dump_asserts_for (file, ssa_name (i));
3478 fprintf (file, "\n");
3482 /* Dump all the registered assertions for all the names to stderr. */
3485 debug_all_asserts (void)
3487 dump_all_asserts (stderr);
3491 /* If NAME doesn't have an ASSERT_EXPR registered for asserting
3492 'EXPR COMP_CODE VAL' at a location that dominates block BB or
3493 E->DEST, then register this location as a possible insertion point
3494 for ASSERT_EXPR <NAME, EXPR COMP_CODE VAL>.
3496 BB, E and SI provide the exact insertion point for the new
3497 ASSERT_EXPR. If BB is NULL, then the ASSERT_EXPR is to be inserted
3498 on edge E. Otherwise, if E is NULL, the ASSERT_EXPR is inserted on
3499 BB. If SI points to a COND_EXPR or a SWITCH_EXPR statement, then E
3500 must not be NULL. */
3503 register_new_assert_for (tree name, tree expr,
3504 enum tree_code comp_code,
3508 block_stmt_iterator si)
3510 assert_locus_t n, loc, last_loc;
3512 basic_block dest_bb;
3514 #if defined ENABLE_CHECKING
3515 gcc_assert (bb == NULL || e == NULL);
3518 gcc_assert (TREE_CODE (bsi_stmt (si)) != COND_EXPR
3519 && TREE_CODE (bsi_stmt (si)) != SWITCH_EXPR);
3522 /* The new assertion A will be inserted at BB or E. We need to
3523 determine if the new location is dominated by a previously
3524 registered location for A. If we are doing an edge insertion,
3525 assume that A will be inserted at E->DEST. Note that this is not
3528 If E is a critical edge, it will be split. But even if E is
3529 split, the new block will dominate the same set of blocks that
3532 The reverse, however, is not true, blocks dominated by E->DEST
3533 will not be dominated by the new block created to split E. So,
3534 if the insertion location is on a critical edge, we will not use
3535 the new location to move another assertion previously registered
3536 at a block dominated by E->DEST. */
3537 dest_bb = (bb) ? bb : e->dest;
3539 /* If NAME already has an ASSERT_EXPR registered for COMP_CODE and
3540 VAL at a block dominating DEST_BB, then we don't need to insert a new
3541 one. Similarly, if the same assertion already exists at a block
3542 dominated by DEST_BB and the new location is not on a critical
3543 edge, then update the existing location for the assertion (i.e.,
3544 move the assertion up in the dominance tree).
3546 Note, this is implemented as a simple linked list because there
3547 should not be more than a handful of assertions registered per
3548 name. If this becomes a performance problem, a table hashed by
3549 COMP_CODE and VAL could be implemented. */
3550 loc = asserts_for[SSA_NAME_VERSION (name)];
3555 if (loc->comp_code == comp_code
3557 || operand_equal_p (loc->val, val, 0))
3558 && (loc->expr == expr
3559 || operand_equal_p (loc->expr, expr, 0)))
3561 /* If the assertion NAME COMP_CODE VAL has already been
3562 registered at a basic block that dominates DEST_BB, then
3563 we don't need to insert the same assertion again. Note
3564 that we don't check strict dominance here to avoid
3565 replicating the same assertion inside the same basic
3566 block more than once (e.g., when a pointer is
3567 dereferenced several times inside a block).
3569 An exception to this rule are edge insertions. If the
3570 new assertion is to be inserted on edge E, then it will
3571 dominate all the other insertions that we may want to
3572 insert in DEST_BB. So, if we are doing an edge
3573 insertion, don't do this dominance check. */
3575 && dominated_by_p (CDI_DOMINATORS, dest_bb, loc->bb))
3578 /* Otherwise, if E is not a critical edge and DEST_BB
3579 dominates the existing location for the assertion, move
3580 the assertion up in the dominance tree by updating its
3581 location information. */
3582 if ((e == NULL || !EDGE_CRITICAL_P (e))
3583 && dominated_by_p (CDI_DOMINATORS, loc->bb, dest_bb))
3592 /* Update the last node of the list and move to the next one. */
3597 /* If we didn't find an assertion already registered for
3598 NAME COMP_CODE VAL, add a new one at the end of the list of
3599 assertions associated with NAME. */
3600 n = XNEW (struct assert_locus_d);
3604 n->comp_code = comp_code;
3612 asserts_for[SSA_NAME_VERSION (name)] = n;
3614 bitmap_set_bit (need_assert_for, SSA_NAME_VERSION (name));
3617 /* COND is a predicate which uses NAME. Extract a suitable test code
3618 and value and store them into *CODE_P and *VAL_P so the predicate
3619 is normalized to NAME *CODE_P *VAL_P.
3621 If no extraction was possible, return FALSE, otherwise return TRUE.
3623 If INVERT is true, then we invert the result stored into *CODE_P. */
3626 extract_code_and_val_from_cond (tree name, tree cond, bool invert,
3627 enum tree_code *code_p, tree *val_p)
3629 enum tree_code comp_code;
3632 /* Predicates may be a single SSA name or NAME OP VAL. */
3635 /* If the predicate is a name, it must be NAME, in which
3636 case we create the predicate NAME == true or
3637 NAME == false accordingly. */
3638 comp_code = EQ_EXPR;
3639 val = invert ? boolean_false_node : boolean_true_node;
3643 /* Otherwise, we have a comparison of the form NAME COMP VAL
3644 or VAL COMP NAME. */
3645 if (name == TREE_OPERAND (cond, 1))
3647 /* If the predicate is of the form VAL COMP NAME, flip
3648 COMP around because we need to register NAME as the
3649 first operand in the predicate. */
3650 comp_code = swap_tree_comparison (TREE_CODE (cond));
3651 val = TREE_OPERAND (cond, 0);
3655 /* The comparison is of the form NAME COMP VAL, so the
3656 comparison code remains unchanged. */
3657 comp_code = TREE_CODE (cond);
3658 val = TREE_OPERAND (cond, 1);
3661 /* Invert the comparison code as necessary. */
3663 comp_code = invert_tree_comparison (comp_code, 0);
3665 /* VRP does not handle float types. */
3666 if (SCALAR_FLOAT_TYPE_P (TREE_TYPE (val)))
3669 /* Do not register always-false predicates.
3670 FIXME: this works around a limitation in fold() when dealing with
3671 enumerations. Given 'enum { N1, N2 } x;', fold will not
3672 fold 'if (x > N2)' to 'if (0)'. */
3673 if ((comp_code == GT_EXPR || comp_code == LT_EXPR)
3674 && INTEGRAL_TYPE_P (TREE_TYPE (val)))
3676 tree min = TYPE_MIN_VALUE (TREE_TYPE (val));
3677 tree max = TYPE_MAX_VALUE (TREE_TYPE (val));
3679 if (comp_code == GT_EXPR
3681 || compare_values (val, max) == 0))
3684 if (comp_code == LT_EXPR
3686 || compare_values (val, min) == 0))
3690 *code_p = comp_code;
3695 /* Try to register an edge assertion for SSA name NAME on edge E for
3696 the condition COND contributing to the conditional jump pointed to by BSI.
3697 Invert the condition COND if INVERT is true.
3698 Return true if an assertion for NAME could be registered. */
3701 register_edge_assert_for_2 (tree name, edge e, block_stmt_iterator bsi,
3702 tree cond, bool invert)
3705 enum tree_code comp_code;
3706 bool retval = false;
3708 if (!extract_code_and_val_from_cond (name, cond, invert, &comp_code, &val))
3711 /* Only register an ASSERT_EXPR if NAME was found in the sub-graph
3712 reachable from E. */
3713 if (TEST_BIT (found_in_subgraph, SSA_NAME_VERSION (name))
3714 && !has_single_use (name))
3716 register_new_assert_for (name, name, comp_code, val, NULL, e, bsi);
3720 /* In the case of NAME <= CST and NAME being defined as
3721 NAME = (unsigned) NAME2 + CST2 we can assert NAME2 >= -CST2
3722 and NAME2 <= CST - CST2. We can do the same for NAME > CST.
3723 This catches range and anti-range tests. */
3724 if ((comp_code == LE_EXPR
3725 || comp_code == GT_EXPR)
3726 && TREE_CODE (val) == INTEGER_CST
3727 && TYPE_UNSIGNED (TREE_TYPE (val)))
3729 tree def_stmt = SSA_NAME_DEF_STMT (name);
3730 tree cst2 = NULL_TREE, name2 = NULL_TREE;
3732 /* Extract CST2 from the (optional) addition. */
3733 if (TREE_CODE (def_stmt) == GIMPLE_MODIFY_STMT
3734 && TREE_CODE (GIMPLE_STMT_OPERAND (def_stmt, 1)) == PLUS_EXPR)
3736 name2 = TREE_OPERAND (GIMPLE_STMT_OPERAND (def_stmt, 1), 0);
3737 cst2 = TREE_OPERAND (GIMPLE_STMT_OPERAND (def_stmt, 1), 1);
3738 if (TREE_CODE (name2) == SSA_NAME
3739 && TREE_CODE (cst2) == INTEGER_CST)
3740 def_stmt = SSA_NAME_DEF_STMT (name2);
3743 /* Extract NAME2 from the (optional) cast. */
3744 if (TREE_CODE (def_stmt) == GIMPLE_MODIFY_STMT
3745 && TREE_CODE (GIMPLE_STMT_OPERAND (def_stmt, 1)) == NOP_EXPR)
3746 name2 = TREE_OPERAND (GIMPLE_STMT_OPERAND (def_stmt, 1), 0);
3748 if (name2 != NULL_TREE
3749 && TREE_CODE (name2) == SSA_NAME
3750 && (cst2 == NULL_TREE
3751 || TREE_CODE (cst2) == INTEGER_CST)
3752 && TREE_CODE (TREE_TYPE (name2)) == INTEGER_TYPE
3753 && TEST_BIT (found_in_subgraph, SSA_NAME_VERSION (name2))
3754 && !has_single_use (name2))
3758 /* Build an expression for the range test. */
3760 if (TREE_TYPE (name) != TREE_TYPE (name2))
3761 tmp = build1 (NOP_EXPR, TREE_TYPE (name), tmp);
3762 if (cst2 != NULL_TREE)
3763 tmp = build2 (PLUS_EXPR, TREE_TYPE (name), tmp, cst2);
3767 fprintf (dump_file, "Adding assert for ");
3768 print_generic_expr (dump_file, name2, 0);
3769 fprintf (dump_file, " from ");
3770 print_generic_expr (dump_file, tmp, 0);
3771 fprintf (dump_file, "\n");
3774 register_new_assert_for (name2, tmp, comp_code, val, NULL, e, bsi);
3783 /* OP is an operand of a truth value expression which is known to have
3784 a particular value. Register any asserts for OP and for any
3785 operands in OP's defining statement.
3787 If CODE is EQ_EXPR, then we want to register OP is zero (false),
3788 if CODE is NE_EXPR, then we want to register OP is nonzero (true). */
3791 register_edge_assert_for_1 (tree op, enum tree_code code,
3792 edge e, block_stmt_iterator bsi)
3794 bool retval = false;
3795 tree op_def, rhs, val;
3797 /* We only care about SSA_NAMEs. */
3798 if (TREE_CODE (op) != SSA_NAME)
3801 /* We know that OP will have a zero or nonzero value. If OP is used
3802 more than once go ahead and register an assert for OP.
3804 The FOUND_IN_SUBGRAPH support is not helpful in this situation as
3805 it will always be set for OP (because OP is used in a COND_EXPR in
3807 if (!has_single_use (op))
3809 val = build_int_cst (TREE_TYPE (op), 0);
3810 register_new_assert_for (op, op, code, val, NULL, e, bsi);
3814 /* Now look at how OP is set. If it's set from a comparison,
3815 a truth operation or some bit operations, then we may be able
3816 to register information about the operands of that assignment. */
3817 op_def = SSA_NAME_DEF_STMT (op);
3818 if (TREE_CODE (op_def) != GIMPLE_MODIFY_STMT)
3821 rhs = GIMPLE_STMT_OPERAND (op_def, 1);
3823 if (COMPARISON_CLASS_P (rhs))
3825 bool invert = (code == EQ_EXPR ? true : false);
3826 tree op0 = TREE_OPERAND (rhs, 0);
3827 tree op1 = TREE_OPERAND (rhs, 1);
3829 if (TREE_CODE (op0) == SSA_NAME)
3830 retval |= register_edge_assert_for_2 (op0, e, bsi, rhs, invert);
3831 if (TREE_CODE (op1) == SSA_NAME)
3832 retval |= register_edge_assert_for_2 (op1, e, bsi, rhs, invert);
3834 else if ((code == NE_EXPR
3835 && (TREE_CODE (rhs) == TRUTH_AND_EXPR
3836 || TREE_CODE (rhs) == BIT_AND_EXPR))
3838 && (TREE_CODE (rhs) == TRUTH_OR_EXPR
3839 || TREE_CODE (rhs) == BIT_IOR_EXPR)))
3841 /* Recurse on each operand. */
3842 retval |= register_edge_assert_for_1 (TREE_OPERAND (rhs, 0),
3844 retval |= register_edge_assert_for_1 (TREE_OPERAND (rhs, 1),
3847 else if (TREE_CODE (rhs) == TRUTH_NOT_EXPR)
3849 /* Recurse, flipping CODE. */
3850 code = invert_tree_comparison (code, false);
3851 retval |= register_edge_assert_for_1 (TREE_OPERAND (rhs, 0),
3854 else if (TREE_CODE (rhs) == SSA_NAME)
3856 /* Recurse through the copy. */
3857 retval |= register_edge_assert_for_1 (rhs, code, e, bsi);
3859 else if (TREE_CODE (rhs) == NOP_EXPR
3860 || TREE_CODE (rhs) == CONVERT_EXPR
3861 || TREE_CODE (rhs) == NON_LVALUE_EXPR)
3863 /* Recurse through the type conversion. */
3864 retval |= register_edge_assert_for_1 (TREE_OPERAND (rhs, 0),
3871 /* Try to register an edge assertion for SSA name NAME on edge E for
3872 the condition COND contributing to the conditional jump pointed to by SI.
3873 Return true if an assertion for NAME could be registered. */
3876 register_edge_assert_for (tree name, edge e, block_stmt_iterator si, tree cond)
3879 enum tree_code comp_code;
3880 bool retval = false;
3881 bool is_else_edge = (e->flags & EDGE_FALSE_VALUE) != 0;
3883 /* Do not attempt to infer anything in names that flow through
3885 if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (name))
3888 if (!extract_code_and_val_from_cond (name, cond, is_else_edge,
3892 /* Register ASSERT_EXPRs for name. */
3893 retval |= register_edge_assert_for_2 (name, e, si, cond, is_else_edge);
3896 /* If COND is effectively an equality test of an SSA_NAME against
3897 the value zero or one, then we may be able to assert values
3898 for SSA_NAMEs which flow into COND. */
3900 /* In the case of NAME == 1 or NAME != 0, for TRUTH_AND_EXPR defining
3901 statement of NAME we can assert both operands of the TRUTH_AND_EXPR
3902 have nonzero value. */
3903 if (((comp_code == EQ_EXPR && integer_onep (val))
3904 || (comp_code == NE_EXPR && integer_zerop (val))))
3906 tree def_stmt = SSA_NAME_DEF_STMT (name);
3908 if (TREE_CODE (def_stmt) == GIMPLE_MODIFY_STMT
3909 && (TREE_CODE (GIMPLE_STMT_OPERAND (def_stmt, 1)) == TRUTH_AND_EXPR
3910 || TREE_CODE (GIMPLE_STMT_OPERAND (def_stmt, 1)) == BIT_AND_EXPR))
3912 tree op0 = TREE_OPERAND (GIMPLE_STMT_OPERAND (def_stmt, 1), 0);
3913 tree op1 = TREE_OPERAND (GIMPLE_STMT_OPERAND (def_stmt, 1), 1);
3914 retval |= register_edge_assert_for_1 (op0, NE_EXPR, e, si);
3915 retval |= register_edge_assert_for_1 (op1, NE_EXPR, e, si);
3919 /* In the case of NAME == 0 or NAME != 1, for TRUTH_OR_EXPR defining
3920 statement of NAME we can assert both operands of the TRUTH_OR_EXPR
3922 if (((comp_code == EQ_EXPR && integer_zerop (val))
3923 || (comp_code == NE_EXPR && integer_onep (val))))
3925 tree def_stmt = SSA_NAME_DEF_STMT (name);
3927 if (TREE_CODE (def_stmt) == GIMPLE_MODIFY_STMT
3928 && (TREE_CODE (GIMPLE_STMT_OPERAND (def_stmt, 1)) == TRUTH_OR_EXPR
3929 /* For BIT_IOR_EXPR only if NAME == 0 both operands have
3930 necessarily zero value. */
3931 || (comp_code == EQ_EXPR
3932 && (TREE_CODE (GIMPLE_STMT_OPERAND (def_stmt, 1))
3935 tree op0 = TREE_OPERAND (GIMPLE_STMT_OPERAND (def_stmt, 1), 0);
3936 tree op1 = TREE_OPERAND (GIMPLE_STMT_OPERAND (def_stmt, 1), 1);
3937 retval |= register_edge_assert_for_1 (op0, EQ_EXPR, e, si);
3938 retval |= register_edge_assert_for_1 (op1, EQ_EXPR, e, si);
3946 static bool find_assert_locations (basic_block bb);
3948 /* Determine whether the outgoing edges of BB should receive an
3949 ASSERT_EXPR for each of the operands of BB's LAST statement.
3950 The last statement of BB must be a COND_EXPR.
3952 If any of the sub-graphs rooted at BB have an interesting use of
3953 the predicate operands, an assert location node is added to the
3954 list of assertions for the corresponding operands. */
3957 find_conditional_asserts (basic_block bb, tree last)
3960 block_stmt_iterator bsi;
3966 need_assert = false;
3967 bsi = bsi_for_stmt (last);
3969 /* Look for uses of the operands in each of the sub-graphs
3970 rooted at BB. We need to check each of the outgoing edges
3971 separately, so that we know what kind of ASSERT_EXPR to
3973 FOR_EACH_EDGE (e, ei, bb->succs)
3978 /* Remove the COND_EXPR operands from the FOUND_IN_SUBGRAPH bitmap.
3979 Otherwise, when we finish traversing each of the sub-graphs, we
3980 won't know whether the variables were found in the sub-graphs or
3981 if they had been found in a block upstream from BB.
3983 This is actually a bad idea is some cases, particularly jump
3984 threading. Consider a CFG like the following:
3994 Assume that one or more operands in the conditional at the
3995 end of block 0 are used in a conditional in block 2, but not
3996 anywhere in block 1. In this case we will not insert any
3997 assert statements in block 1, which may cause us to miss
3998 opportunities to optimize, particularly for jump threading. */
3999 FOR_EACH_SSA_TREE_OPERAND (op, last, iter, SSA_OP_USE)
4000 RESET_BIT (found_in_subgraph, SSA_NAME_VERSION (op));
4002 /* Traverse the strictly dominated sub-graph rooted at E->DEST
4003 to determine if any of the operands in the conditional
4004 predicate are used. */
4005 need_assert |= find_assert_locations (e->dest);
4007 /* Register the necessary assertions for each operand in the
4008 conditional predicate. */
4009 FOR_EACH_SSA_TREE_OPERAND (op, last, iter, SSA_OP_USE)
4010 need_assert |= register_edge_assert_for (op, e, bsi,
4011 COND_EXPR_COND (last));
4014 /* Finally, indicate that we have found the operands in the
4016 FOR_EACH_SSA_TREE_OPERAND (op, last, iter, SSA_OP_USE)
4017 SET_BIT (found_in_subgraph, SSA_NAME_VERSION (op));
4022 /* Compare two case labels sorting first by the destination label uid
4023 and then by the case value. */
4026 compare_case_labels (const void *p1, const void *p2)
4028 const_tree const case1 = *(const_tree const*)p1;
4029 const_tree const case2 = *(const_tree const*)p2;
4030 unsigned int uid1 = DECL_UID (CASE_LABEL (case1));
4031 unsigned int uid2 = DECL_UID (CASE_LABEL (case2));
4035 else if (uid1 == uid2)
4037 /* Make sure the default label is first in a group. */
4038 if (!CASE_LOW (case1))
4040 else if (!CASE_LOW (case2))
4043 return tree_int_cst_compare (CASE_LOW (case1), CASE_LOW (case2));
4049 /* Determine whether the outgoing edges of BB should receive an
4050 ASSERT_EXPR for each of the operands of BB's LAST statement.
4051 The last statement of BB must be a SWITCH_EXPR.
4053 If any of the sub-graphs rooted at BB have an interesting use of
4054 the predicate operands, an assert location node is added to the
4055 list of assertions for the corresponding operands. */
4058 find_switch_asserts (basic_block bb, tree last)
4061 block_stmt_iterator bsi;
4064 tree vec = SWITCH_LABELS (last), vec2;
4065 size_t n = TREE_VEC_LENGTH (vec);
4068 need_assert = false;
4069 bsi = bsi_for_stmt (last);
4070 op = TREE_OPERAND (last, 0);
4071 if (TREE_CODE (op) != SSA_NAME)
4074 /* Build a vector of case labels sorted by destination label. */
4075 vec2 = make_tree_vec (n);
4076 for (idx = 0; idx < n; ++idx)
4077 TREE_VEC_ELT (vec2, idx) = TREE_VEC_ELT (vec, idx);
4078 qsort (&TREE_VEC_ELT (vec2, 0), n, sizeof (tree), compare_case_labels);
4080 for (idx = 0; idx < n; ++idx)
4083 tree cl = TREE_VEC_ELT (vec2, idx);
4085 min = CASE_LOW (cl);
4086 max = CASE_HIGH (cl);
4088 /* If there are multiple case labels with the same destination
4089 we need to combine them to a single value range for the edge. */
4091 && CASE_LABEL (cl) == CASE_LABEL (TREE_VEC_ELT (vec2, idx + 1)))
4093 /* Skip labels until the last of the group. */
4097 && CASE_LABEL (cl) == CASE_LABEL (TREE_VEC_ELT (vec2, idx)));
4100 /* Pick up the maximum of the case label range. */
4101 if (CASE_HIGH (TREE_VEC_ELT (vec2, idx)))
4102 max = CASE_HIGH (TREE_VEC_ELT (vec2, idx));
4104 max = CASE_LOW (TREE_VEC_ELT (vec2, idx));
4107 /* Nothing to do if the range includes the default label until we
4108 can register anti-ranges. */
4109 if (min == NULL_TREE)
4112 /* Find the edge to register the assert expr on. */
4113 e = find_edge (bb, label_to_block (CASE_LABEL (cl)));
4115 /* Remove the SWITCH_EXPR operand from the FOUND_IN_SUBGRAPH bitmap.
4116 Otherwise, when we finish traversing each of the sub-graphs, we
4117 won't know whether the variables were found in the sub-graphs or
4118 if they had been found in a block upstream from BB. */
4119 RESET_BIT (found_in_subgraph, SSA_NAME_VERSION (op));
4121 /* Traverse the strictly dominated sub-graph rooted at E->DEST
4122 to determine if any of the operands in the conditional
4123 predicate are used. */
4125 need_assert |= find_assert_locations (e->dest);
4127 /* Register the necessary assertions for the operand in the
4129 cond = build2 (max ? GE_EXPR : EQ_EXPR, boolean_type_node,
4130 op, fold_convert (TREE_TYPE (op), min));
4131 need_assert |= register_edge_assert_for (op, e, bsi, cond);
4134 cond = build2 (LE_EXPR, boolean_type_node,
4135 op, fold_convert (TREE_TYPE (op), max));
4136 need_assert |= register_edge_assert_for (op, e, bsi, cond);
4140 /* Finally, indicate that we have found the operand in the
4142 SET_BIT (found_in_subgraph, SSA_NAME_VERSION (op));
4148 /* Traverse all the statements in block BB looking for statements that
4149 may generate useful assertions for the SSA names in their operand.
4150 If a statement produces a useful assertion A for name N_i, then the
4151 list of assertions already generated for N_i is scanned to
4152 determine if A is actually needed.
4154 If N_i already had the assertion A at a location dominating the
4155 current location, then nothing needs to be done. Otherwise, the
4156 new location for A is recorded instead.
4158 1- For every statement S in BB, all the variables used by S are
4159 added to bitmap FOUND_IN_SUBGRAPH.
4161 2- If statement S uses an operand N in a way that exposes a known
4162 value range for N, then if N was not already generated by an
4163 ASSERT_EXPR, create a new assert location for N. For instance,
4164 if N is a pointer and the statement dereferences it, we can
4165 assume that N is not NULL.
4167 3- COND_EXPRs are a special case of #2. We can derive range
4168 information from the predicate but need to insert different
4169 ASSERT_EXPRs for each of the sub-graphs rooted at the
4170 conditional block. If the last statement of BB is a conditional
4171 expression of the form 'X op Y', then
4173 a) Remove X and Y from the set FOUND_IN_SUBGRAPH.
4175 b) If the conditional is the only entry point to the sub-graph
4176 corresponding to the THEN_CLAUSE, recurse into it. On
4177 return, if X and/or Y are marked in FOUND_IN_SUBGRAPH, then
4178 an ASSERT_EXPR is added for the corresponding variable.
4180 c) Repeat step (b) on the ELSE_CLAUSE.
4182 d) Mark X and Y in FOUND_IN_SUBGRAPH.
4191 In this case, an assertion on the THEN clause is useful to
4192 determine that 'a' is always 9 on that edge. However, an assertion
4193 on the ELSE clause would be unnecessary.
4195 4- If BB does not end in a conditional expression, then we recurse
4196 into BB's dominator children.
4198 At the end of the recursive traversal, every SSA name will have a
4199 list of locations where ASSERT_EXPRs should be added. When a new
4200 location for name N is found, it is registered by calling
4201 register_new_assert_for. That function keeps track of all the
4202 registered assertions to prevent adding unnecessary assertions.
4203 For instance, if a pointer P_4 is dereferenced more than once in a
4204 dominator tree, only the location dominating all the dereference of
4205 P_4 will receive an ASSERT_EXPR.
4207 If this function returns true, then it means that there are names
4208 for which we need to generate ASSERT_EXPRs. Those assertions are
4209 inserted by process_assert_insertions. */
4212 find_assert_locations (basic_block bb)
4214 block_stmt_iterator si;
4219 if (TEST_BIT (blocks_visited, bb->index))
4222 SET_BIT (blocks_visited, bb->index);
4224 need_assert = false;
4226 /* Traverse all PHI nodes in BB marking used operands. */
4227 for (phi = phi_nodes (bb); phi; phi = PHI_CHAIN (phi))
4229 use_operand_p arg_p;
4232 FOR_EACH_PHI_ARG (arg_p, phi, i, SSA_OP_USE)
4234 tree arg = USE_FROM_PTR (arg_p);
4235 if (TREE_CODE (arg) == SSA_NAME)
4237 gcc_assert (is_gimple_reg (PHI_RESULT (phi)));
4238 SET_BIT (found_in_subgraph, SSA_NAME_VERSION (arg));
4243 /* Traverse all the statements in BB marking used names and looking
4244 for statements that may infer assertions for their used operands. */
4246 for (si = bsi_start (bb); !bsi_end_p (si); bsi_next (&si))
4251 stmt = bsi_stmt (si);
4253 /* See if we can derive an assertion for any of STMT's operands. */
4254 FOR_EACH_SSA_TREE_OPERAND (op, stmt, i, SSA_OP_USE)
4257 enum tree_code comp_code;
4259 /* Mark OP in bitmap FOUND_IN_SUBGRAPH. If STMT is inside
4260 the sub-graph of a conditional block, when we return from
4261 this recursive walk, our parent will use the
4262 FOUND_IN_SUBGRAPH bitset to determine if one of the
4263 operands it was looking for was present in the sub-graph. */
4264 SET_BIT (found_in_subgraph, SSA_NAME_VERSION (op));
4266 /* If OP is used in such a way that we can infer a value
4267 range for it, and we don't find a previous assertion for
4268 it, create a new assertion location node for OP. */
4269 if (infer_value_range (stmt, op, &comp_code, &value))
4271 /* If we are able to infer a nonzero value range for OP,
4272 then walk backwards through the use-def chain to see if OP
4273 was set via a typecast.
4275 If so, then we can also infer a nonzero value range
4276 for the operand of the NOP_EXPR. */
4277 if (comp_code == NE_EXPR && integer_zerop (value))
4280 tree def_stmt = SSA_NAME_DEF_STMT (t);
4282 while (TREE_CODE (def_stmt) == GIMPLE_MODIFY_STMT
4284 (GIMPLE_STMT_OPERAND (def_stmt, 1)) == NOP_EXPR
4286 (TREE_OPERAND (GIMPLE_STMT_OPERAND (def_stmt, 1),
4289 (TREE_TYPE (TREE_OPERAND
4290 (GIMPLE_STMT_OPERAND (def_stmt,
4293 t = TREE_OPERAND (GIMPLE_STMT_OPERAND (def_stmt, 1), 0);
4294 def_stmt = SSA_NAME_DEF_STMT (t);
4296 /* Note we want to register the assert for the
4297 operand of the NOP_EXPR after SI, not after the
4299 if (! has_single_use (t))
4301 register_new_assert_for (t, t, comp_code, value,
4308 /* If OP is used only once, namely in this STMT, don't
4309 bother creating an ASSERT_EXPR for it. Such an
4310 ASSERT_EXPR would do nothing but increase compile time. */
4311 if (!has_single_use (op))
4313 register_new_assert_for (op, op, comp_code, value,
4320 /* Remember the last statement of the block. */
4324 /* If BB's last statement is a conditional expression
4325 involving integer operands, recurse into each of the sub-graphs
4326 rooted at BB to determine if we need to add ASSERT_EXPRs. */
4328 && TREE_CODE (last) == COND_EXPR
4329 && !fp_predicate (COND_EXPR_COND (last))
4330 && !ZERO_SSA_OPERANDS (last, SSA_OP_USE))
4331 need_assert |= find_conditional_asserts (bb, last);
4334 && TREE_CODE (last) == SWITCH_EXPR
4335 && !ZERO_SSA_OPERANDS (last, SSA_OP_USE))
4336 need_assert |= find_switch_asserts (bb, last);
4338 /* Recurse into the dominator children of BB. */
4339 for (son = first_dom_son (CDI_DOMINATORS, bb);
4341 son = next_dom_son (CDI_DOMINATORS, son))
4342 need_assert |= find_assert_locations (son);
4348 /* Create an ASSERT_EXPR for NAME and insert it in the location
4349 indicated by LOC. Return true if we made any edge insertions. */
4352 process_assert_insertions_for (tree name, assert_locus_t loc)
4354 /* Build the comparison expression NAME_i COMP_CODE VAL. */
4355 tree stmt, cond, assert_expr;
4359 cond = build2 (loc->comp_code, boolean_type_node, loc->expr, loc->val);
4360 assert_expr = build_assert_expr_for (cond, name);
4364 /* We have been asked to insert the assertion on an edge. This
4365 is used only by COND_EXPR and SWITCH_EXPR assertions. */
4366 #if defined ENABLE_CHECKING
4367 gcc_assert (TREE_CODE (bsi_stmt (loc->si)) == COND_EXPR
4368 || TREE_CODE (bsi_stmt (loc->si)) == SWITCH_EXPR);
4371 bsi_insert_on_edge (loc->e, assert_expr);
4375 /* Otherwise, we can insert right after LOC->SI iff the
4376 statement must not be the last statement in the block. */
4377 stmt = bsi_stmt (loc->si);
4378 if (!stmt_ends_bb_p (stmt))
4380 bsi_insert_after (&loc->si, assert_expr, BSI_SAME_STMT);
4384 /* If STMT must be the last statement in BB, we can only insert new
4385 assertions on the non-abnormal edge out of BB. Note that since
4386 STMT is not control flow, there may only be one non-abnormal edge
4388 FOR_EACH_EDGE (e, ei, loc->bb->succs)
4389 if (!(e->flags & EDGE_ABNORMAL))
4391 bsi_insert_on_edge (e, assert_expr);
4399 /* Process all the insertions registered for every name N_i registered
4400 in NEED_ASSERT_FOR. The list of assertions to be inserted are
4401 found in ASSERTS_FOR[i]. */
4404 process_assert_insertions (void)
4408 bool update_edges_p = false;
4409 int num_asserts = 0;
4411 if (dump_file && (dump_flags & TDF_DETAILS))
4412 dump_all_asserts (dump_file);
4414 EXECUTE_IF_SET_IN_BITMAP (need_assert_for, 0, i, bi)
4416 assert_locus_t loc = asserts_for[i];
4421 assert_locus_t next = loc->next;
4422 update_edges_p |= process_assert_insertions_for (ssa_name (i), loc);
4430 bsi_commit_edge_inserts ();
4432 if (dump_file && (dump_flags & TDF_STATS))
4433 fprintf (dump_file, "\nNumber of ASSERT_EXPR expressions inserted: %d\n\n",
4438 /* Traverse the flowgraph looking for conditional jumps to insert range
4439 expressions. These range expressions are meant to provide information
4440 to optimizations that need to reason in terms of value ranges. They
4441 will not be expanded into RTL. For instance, given:
4450 this pass will transform the code into:
4456 x = ASSERT_EXPR <x, x < y>
4461 y = ASSERT_EXPR <y, x <= y>
4465 The idea is that once copy and constant propagation have run, other
4466 optimizations will be able to determine what ranges of values can 'x'
4467 take in different paths of the code, simply by checking the reaching
4468 definition of 'x'. */
4471 insert_range_assertions (void)
4477 found_in_subgraph = sbitmap_alloc (num_ssa_names);
4478 sbitmap_zero (found_in_subgraph);
4480 blocks_visited = sbitmap_alloc (last_basic_block);
4481 sbitmap_zero (blocks_visited);
4483 need_assert_for = BITMAP_ALLOC (NULL);
4484 asserts_for = XCNEWVEC (assert_locus_t, num_ssa_names);
4486 calculate_dominance_info (CDI_DOMINATORS);
4488 update_ssa_p = false;
4489 FOR_EACH_EDGE (e, ei, ENTRY_BLOCK_PTR->succs)
4490 if (find_assert_locations (e->dest))
4491 update_ssa_p = true;
4495 process_assert_insertions ();
4496 update_ssa (TODO_update_ssa_no_phi);
4499 if (dump_file && (dump_flags & TDF_DETAILS))
4501 fprintf (dump_file, "\nSSA form after inserting ASSERT_EXPRs\n");
4502 dump_function_to_file (current_function_decl, dump_file, dump_flags);
4505 sbitmap_free (found_in_subgraph);
4507 BITMAP_FREE (need_assert_for);
4510 /* Checks one ARRAY_REF in REF, located at LOCUS. Ignores flexible arrays
4511 and "struct" hacks. If VRP can determine that the
4512 array subscript is a constant, check if it is outside valid
4513 range. If the array subscript is a RANGE, warn if it is
4514 non-overlapping with valid range.
4515 IGNORE_OFF_BY_ONE is true if the ARRAY_REF is inside a ADDR_EXPR. */
4518 check_array_ref (tree ref, location_t* locus, bool ignore_off_by_one)
4520 value_range_t* vr = NULL;
4521 tree low_sub, up_sub;
4522 tree low_bound, up_bound = array_ref_up_bound (ref);
4524 low_sub = up_sub = TREE_OPERAND (ref, 1);
4526 if (!up_bound || TREE_NO_WARNING (ref)
4527 || TREE_CODE (up_bound) != INTEGER_CST
4528 /* Can not check flexible arrays. */
4529 || (TYPE_SIZE (TREE_TYPE (ref)) == NULL_TREE
4530 && TYPE_DOMAIN (TREE_TYPE (ref)) != NULL_TREE
4531 && TYPE_MAX_VALUE (TYPE_DOMAIN (TREE_TYPE (ref))) == NULL_TREE)
4532 /* Accesses after the end of arrays of size 0 (gcc
4533 extension) and 1 are likely intentional ("struct
4535 || compare_tree_int (up_bound, 1) <= 0)
4538 low_bound = array_ref_low_bound (ref);
4540 if (TREE_CODE (low_sub) == SSA_NAME)
4542 vr = get_value_range (low_sub);
4543 if (vr->type == VR_RANGE || vr->type == VR_ANTI_RANGE)
4545 low_sub = vr->type == VR_RANGE ? vr->max : vr->min;
4546 up_sub = vr->type == VR_RANGE ? vr->min : vr->max;
4550 if (vr && vr->type == VR_ANTI_RANGE)
4552 if (TREE_CODE (up_sub) == INTEGER_CST
4553 && tree_int_cst_lt (up_bound, up_sub)
4554 && TREE_CODE (low_sub) == INTEGER_CST
4555 && tree_int_cst_lt (low_sub, low_bound))
4557 warning (OPT_Warray_bounds,
4558 "%Harray subscript is outside array bounds", locus);
4559 TREE_NO_WARNING (ref) = 1;
4562 else if (TREE_CODE (up_sub) == INTEGER_CST
4563 && tree_int_cst_lt (up_bound, up_sub)
4564 && !tree_int_cst_equal (up_bound, up_sub)
4565 && (!ignore_off_by_one
4566 || !tree_int_cst_equal (int_const_binop (PLUS_EXPR,
4572 warning (OPT_Warray_bounds, "%Harray subscript is above array bounds",
4574 TREE_NO_WARNING (ref) = 1;
4576 else if (TREE_CODE (low_sub) == INTEGER_CST
4577 && tree_int_cst_lt (low_sub, low_bound))
4579 warning (OPT_Warray_bounds, "%Harray subscript is below array bounds",
4581 TREE_NO_WARNING (ref) = 1;
4585 /* Searches if the expr T, located at LOCATION computes
4586 address of an ARRAY_REF, and call check_array_ref on it. */
4589 search_for_addr_array(tree t, location_t* location)
4591 while (TREE_CODE (t) == SSA_NAME)
4593 t = SSA_NAME_DEF_STMT (t);
4594 if (TREE_CODE (t) != GIMPLE_MODIFY_STMT)
4596 t = GIMPLE_STMT_OPERAND (t, 1);
4600 /* We are only interested in addresses of ARRAY_REF's. */
4601 if (TREE_CODE (t) != ADDR_EXPR)
4604 /* Check each ARRAY_REFs in the reference chain. */
4607 if (TREE_CODE (t) == ARRAY_REF)
4608 check_array_ref (t, location, true /*ignore_off_by_one*/);
4610 t = TREE_OPERAND(t,0);
4612 while (handled_component_p (t));
4615 /* walk_tree() callback that checks if *TP is
4616 an ARRAY_REF inside an ADDR_EXPR (in which an array
4617 subscript one outside the valid range is allowed). Call
4618 check_array_ref for each ARRAY_REF found. The location is
4622 check_array_bounds (tree *tp, int *walk_subtree, void *data)
4625 tree stmt = (tree)data;
4626 location_t *location = EXPR_LOCUS (stmt);
4628 if (!EXPR_HAS_LOCATION (stmt))
4630 *walk_subtree = FALSE;
4634 *walk_subtree = TRUE;
4636 if (TREE_CODE (t) == ARRAY_REF)
4637 check_array_ref (t, location, false /*ignore_off_by_one*/);
4639 if (TREE_CODE (t) == INDIRECT_REF
4640 || (TREE_CODE (t) == RETURN_EXPR && TREE_OPERAND (t, 0)))
4641 search_for_addr_array (TREE_OPERAND (t, 0), location);
4642 else if (TREE_CODE (t) == CALL_EXPR)
4645 call_expr_arg_iterator iter;
4647 FOR_EACH_CALL_EXPR_ARG (arg, iter, t)
4648 search_for_addr_array (arg, location);
4651 if (TREE_CODE (t) == ADDR_EXPR)
4652 *walk_subtree = FALSE;
4657 /* Walk over all statements of all reachable BBs and call check_array_bounds
4661 check_all_array_refs (void)
4664 block_stmt_iterator si;
4668 /* Skip bb's that are clearly unreachable. */
4669 if (single_pred_p (bb))
4671 basic_block pred_bb = EDGE_PRED (bb, 0)->src;
4672 tree ls = NULL_TREE;
4674 if (!bsi_end_p (bsi_last (pred_bb)))
4675 ls = bsi_stmt (bsi_last (pred_bb));
4677 if (ls && TREE_CODE (ls) == COND_EXPR
4678 && ((COND_EXPR_COND (ls) == boolean_false_node
4679 && (EDGE_PRED (bb, 0)->flags & EDGE_TRUE_VALUE))
4680 || (COND_EXPR_COND (ls) == boolean_true_node
4681 && (EDGE_PRED (bb, 0)->flags & EDGE_FALSE_VALUE))))
4684 for (si = bsi_start (bb); !bsi_end_p (si); bsi_next (&si))
4685 walk_tree (bsi_stmt_ptr (si), check_array_bounds,
4686 bsi_stmt (si), NULL);
4690 /* Convert range assertion expressions into the implied copies and
4691 copy propagate away the copies. Doing the trivial copy propagation
4692 here avoids the need to run the full copy propagation pass after
4695 FIXME, this will eventually lead to copy propagation removing the
4696 names that had useful range information attached to them. For
4697 instance, if we had the assertion N_i = ASSERT_EXPR <N_j, N_j > 3>,
4698 then N_i will have the range [3, +INF].
4700 However, by converting the assertion into the implied copy
4701 operation N_i = N_j, we will then copy-propagate N_j into the uses
4702 of N_i and lose the range information. We may want to hold on to
4703 ASSERT_EXPRs a little while longer as the ranges could be used in
4704 things like jump threading.
4706 The problem with keeping ASSERT_EXPRs around is that passes after
4707 VRP need to handle them appropriately.
4709 Another approach would be to make the range information a first
4710 class property of the SSA_NAME so that it can be queried from
4711 any pass. This is made somewhat more complex by the need for
4712 multiple ranges to be associated with one SSA_NAME. */
4715 remove_range_assertions (void)
4718 block_stmt_iterator si;
4720 /* Note that the BSI iterator bump happens at the bottom of the
4721 loop and no bump is necessary if we're removing the statement
4722 referenced by the current BSI. */
4724 for (si = bsi_start (bb); !bsi_end_p (si);)
4726 tree stmt = bsi_stmt (si);
4729 if (TREE_CODE (stmt) == GIMPLE_MODIFY_STMT
4730 && TREE_CODE (GIMPLE_STMT_OPERAND (stmt, 1)) == ASSERT_EXPR)
4732 tree rhs = GIMPLE_STMT_OPERAND (stmt, 1), var;
4733 tree cond = fold (ASSERT_EXPR_COND (rhs));
4734 use_operand_p use_p;
4735 imm_use_iterator iter;
4737 gcc_assert (cond != boolean_false_node);
4739 /* Propagate the RHS into every use of the LHS. */
4740 var = ASSERT_EXPR_VAR (rhs);
4741 FOR_EACH_IMM_USE_STMT (use_stmt, iter,
4742 GIMPLE_STMT_OPERAND (stmt, 0))
4743 FOR_EACH_IMM_USE_ON_STMT (use_p, iter)
4745 SET_USE (use_p, var);
4746 gcc_assert (TREE_CODE (var) == SSA_NAME);
4749 /* And finally, remove the copy, it is not needed. */
4750 bsi_remove (&si, true);
4751 release_defs (stmt);
4757 sbitmap_free (blocks_visited);
4761 /* Return true if STMT is interesting for VRP. */
4764 stmt_interesting_for_vrp (tree stmt)
4766 if (TREE_CODE (stmt) == PHI_NODE
4767 && is_gimple_reg (PHI_RESULT (stmt))
4768 && (INTEGRAL_TYPE_P (TREE_TYPE (PHI_RESULT (stmt)))
4769 || POINTER_TYPE_P (TREE_TYPE (PHI_RESULT (stmt)))))
4771 else if (TREE_CODE (stmt) == GIMPLE_MODIFY_STMT)
4773 tree lhs = GIMPLE_STMT_OPERAND (stmt, 0);
4774 tree rhs = GIMPLE_STMT_OPERAND (stmt, 1);
4776 /* In general, assignments with virtual operands are not useful
4777 for deriving ranges, with the obvious exception of calls to
4778 builtin functions. */
4779 if (TREE_CODE (lhs) == SSA_NAME
4780 && (INTEGRAL_TYPE_P (TREE_TYPE (lhs))
4781 || POINTER_TYPE_P (TREE_TYPE (lhs)))
4782 && ((TREE_CODE (rhs) == CALL_EXPR
4783 && TREE_CODE (CALL_EXPR_FN (rhs)) == ADDR_EXPR
4784 && DECL_P (TREE_OPERAND (CALL_EXPR_FN (rhs), 0))
4785 && DECL_IS_BUILTIN (TREE_OPERAND (CALL_EXPR_FN (rhs), 0)))
4786 || ZERO_SSA_OPERANDS (stmt, SSA_OP_ALL_VIRTUALS)))
4789 else if (TREE_CODE (stmt) == COND_EXPR || TREE_CODE (stmt) == SWITCH_EXPR)
4796 /* Initialize local data structures for VRP. */
4799 vrp_initialize (void)
4803 vr_value = XCNEWVEC (value_range_t *, num_ssa_names);
4804 vr_phi_edge_counts = XCNEWVEC (int, num_ssa_names);
4808 block_stmt_iterator si;
4811 for (phi = phi_nodes (bb); phi; phi = PHI_CHAIN (phi))
4813 if (!stmt_interesting_for_vrp (phi))
4815 tree lhs = PHI_RESULT (phi);
4816 set_value_range_to_varying (get_value_range (lhs));
4817 DONT_SIMULATE_AGAIN (phi) = true;
4820 DONT_SIMULATE_AGAIN (phi) = false;
4823 for (si = bsi_start (bb); !bsi_end_p (si); bsi_next (&si))
4825 tree stmt = bsi_stmt (si);
4827 if (!stmt_interesting_for_vrp (stmt))
4831 FOR_EACH_SSA_TREE_OPERAND (def, stmt, i, SSA_OP_DEF)
4832 set_value_range_to_varying (get_value_range (def));
4833 DONT_SIMULATE_AGAIN (stmt) = true;
4837 DONT_SIMULATE_AGAIN (stmt) = false;
4844 /* Visit assignment STMT. If it produces an interesting range, record
4845 the SSA name in *OUTPUT_P. */
4847 static enum ssa_prop_result
4848 vrp_visit_assignment (tree stmt, tree *output_p)
4853 lhs = GIMPLE_STMT_OPERAND (stmt, 0);
4854 rhs = GIMPLE_STMT_OPERAND (stmt, 1);
4856 /* We only keep track of ranges in integral and pointer types. */
4857 if (TREE_CODE (lhs) == SSA_NAME
4858 && ((INTEGRAL_TYPE_P (TREE_TYPE (lhs))
4859 /* It is valid to have NULL MIN/MAX values on a type. See
4860 build_range_type. */
4861 && TYPE_MIN_VALUE (TREE_TYPE (lhs))
4862 && TYPE_MAX_VALUE (TREE_TYPE (lhs)))
4863 || POINTER_TYPE_P (TREE_TYPE (lhs))))
4866 value_range_t new_vr = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
4868 extract_range_from_expr (&new_vr, rhs);
4870 /* If STMT is inside a loop, we may be able to know something
4871 else about the range of LHS by examining scalar evolution
4873 if (current_loops && (l = loop_containing_stmt (stmt)))
4874 adjust_range_with_scev (&new_vr, l, stmt, lhs);
4876 if (update_value_range (lhs, &new_vr))
4880 if (dump_file && (dump_flags & TDF_DETAILS))
4882 fprintf (dump_file, "Found new range for ");
4883 print_generic_expr (dump_file, lhs, 0);
4884 fprintf (dump_file, ": ");
4885 dump_value_range (dump_file, &new_vr);
4886 fprintf (dump_file, "\n\n");
4889 if (new_vr.type == VR_VARYING)
4890 return SSA_PROP_VARYING;
4892 return SSA_PROP_INTERESTING;
4895 return SSA_PROP_NOT_INTERESTING;
4898 /* Every other statement produces no useful ranges. */
4899 FOR_EACH_SSA_TREE_OPERAND (def, stmt, iter, SSA_OP_DEF)
4900 set_value_range_to_varying (get_value_range (def));
4902 return SSA_PROP_VARYING;
4905 /* Helper that gets the value range of the SSA_NAME with version I
4906 or a symbolic range containing the SSA_NAME only if the value range
4907 is varying or undefined. */
4909 static inline value_range_t
4910 get_vr_for_comparison (int i)
4912 value_range_t vr = *(vr_value[i]);
4914 /* If name N_i does not have a valid range, use N_i as its own
4915 range. This allows us to compare against names that may
4916 have N_i in their ranges. */
4917 if (vr.type == VR_VARYING || vr.type == VR_UNDEFINED)
4920 vr.min = ssa_name (i);
4921 vr.max = ssa_name (i);
4927 /* Compare all the value ranges for names equivalent to VAR with VAL
4928 using comparison code COMP. Return the same value returned by
4929 compare_range_with_value, including the setting of
4930 *STRICT_OVERFLOW_P. */
4933 compare_name_with_value (enum tree_code comp, tree var, tree val,
4934 bool *strict_overflow_p)
4940 int used_strict_overflow;
4942 value_range_t equiv_vr;
4944 /* Get the set of equivalences for VAR. */
4945 e = get_value_range (var)->equiv;
4947 /* Start at -1. Set it to 0 if we do a comparison without relying
4948 on overflow, or 1 if all comparisons rely on overflow. */
4949 used_strict_overflow = -1;
4951 /* Compare vars' value range with val. */
4952 equiv_vr = get_vr_for_comparison (SSA_NAME_VERSION (var));
4954 retval = compare_range_with_value (comp, &equiv_vr, val, &sop);
4956 used_strict_overflow = sop ? 1 : 0;
4958 /* If the equiv set is empty we have done all work we need to do. */
4962 && used_strict_overflow > 0)
4963 *strict_overflow_p = true;
4967 EXECUTE_IF_SET_IN_BITMAP (e, 0, i, bi)
4969 equiv_vr = get_vr_for_comparison (i);
4971 t = compare_range_with_value (comp, &equiv_vr, val, &sop);
4974 /* If we get different answers from different members
4975 of the equivalence set this check must be in a dead
4976 code region. Folding it to a trap representation
4977 would be correct here. For now just return don't-know. */
4987 used_strict_overflow = 0;
4988 else if (used_strict_overflow < 0)
4989 used_strict_overflow = 1;
4994 && used_strict_overflow > 0)
4995 *strict_overflow_p = true;
5001 /* Given a comparison code COMP and names N1 and N2, compare all the
5002 ranges equivalent to N1 against all the ranges equivalent to N2
5003 to determine the value of N1 COMP N2. Return the same value
5004 returned by compare_ranges. Set *STRICT_OVERFLOW_P to indicate
5005 whether we relied on an overflow infinity in the comparison. */
5009 compare_names (enum tree_code comp, tree n1, tree n2,
5010 bool *strict_overflow_p)
5014 bitmap_iterator bi1, bi2;
5016 int used_strict_overflow;
5017 static bitmap_obstack *s_obstack = NULL;
5018 static bitmap s_e1 = NULL, s_e2 = NULL;
5020 /* Compare the ranges of every name equivalent to N1 against the
5021 ranges of every name equivalent to N2. */
5022 e1 = get_value_range (n1)->equiv;
5023 e2 = get_value_range (n2)->equiv;
5025 /* Use the fake bitmaps if e1 or e2 are not available. */
5026 if (s_obstack == NULL)
5028 s_obstack = XNEW (bitmap_obstack);
5029 bitmap_obstack_initialize (s_obstack);
5030 s_e1 = BITMAP_ALLOC (s_obstack);
5031 s_e2 = BITMAP_ALLOC (s_obstack);
5038 /* Add N1 and N2 to their own set of equivalences to avoid
5039 duplicating the body of the loop just to check N1 and N2
5041 bitmap_set_bit (e1, SSA_NAME_VERSION (n1));
5042 bitmap_set_bit (e2, SSA_NAME_VERSION (n2));
5044 /* If the equivalence sets have a common intersection, then the two
5045 names can be compared without checking their ranges. */
5046 if (bitmap_intersect_p (e1, e2))
5048 bitmap_clear_bit (e1, SSA_NAME_VERSION (n1));
5049 bitmap_clear_bit (e2, SSA_NAME_VERSION (n2));
5051 return (comp == EQ_EXPR || comp == GE_EXPR || comp == LE_EXPR)
5053 : boolean_false_node;
5056 /* Start at -1. Set it to 0 if we do a comparison without relying
5057 on overflow, or 1 if all comparisons rely on overflow. */
5058 used_strict_overflow = -1;
5060 /* Otherwise, compare all the equivalent ranges. First, add N1 and
5061 N2 to their own set of equivalences to avoid duplicating the body
5062 of the loop just to check N1 and N2 ranges. */
5063 EXECUTE_IF_SET_IN_BITMAP (e1, 0, i1, bi1)
5065 value_range_t vr1 = get_vr_for_comparison (i1);
5067 t = retval = NULL_TREE;
5068 EXECUTE_IF_SET_IN_BITMAP (e2, 0, i2, bi2)
5072 value_range_t vr2 = get_vr_for_comparison (i2);
5074 t = compare_ranges (comp, &vr1, &vr2, &sop);
5077 /* If we get different answers from different members
5078 of the equivalence set this check must be in a dead
5079 code region. Folding it to a trap representation
5080 would be correct here. For now just return don't-know. */
5084 bitmap_clear_bit (e1, SSA_NAME_VERSION (n1));
5085 bitmap_clear_bit (e2, SSA_NAME_VERSION (n2));
5091 used_strict_overflow = 0;
5092 else if (used_strict_overflow < 0)
5093 used_strict_overflow = 1;
5099 bitmap_clear_bit (e1, SSA_NAME_VERSION (n1));
5100 bitmap_clear_bit (e2, SSA_NAME_VERSION (n2));
5101 if (used_strict_overflow > 0)
5102 *strict_overflow_p = true;
5107 /* None of the equivalent ranges are useful in computing this
5109 bitmap_clear_bit (e1, SSA_NAME_VERSION (n1));
5110 bitmap_clear_bit (e2, SSA_NAME_VERSION (n2));
5115 /* Given a conditional predicate COND, try to determine if COND yields
5116 true or false based on the value ranges of its operands. Return
5117 BOOLEAN_TRUE_NODE if the conditional always evaluates to true,
5118 BOOLEAN_FALSE_NODE if the conditional always evaluates to false, and,
5119 NULL if the conditional cannot be evaluated at compile time.
5121 If USE_EQUIV_P is true, the ranges of all the names equivalent with
5122 the operands in COND are used when trying to compute its value.
5123 This is only used during final substitution. During propagation,
5124 we only check the range of each variable and not its equivalents.
5126 Set *STRICT_OVERFLOW_P to indicate whether we relied on an overflow
5127 infinity to produce the result. */
5130 vrp_evaluate_conditional_warnv (tree cond, bool use_equiv_p,
5131 bool *strict_overflow_p)
5133 gcc_assert (TREE_CODE (cond) == SSA_NAME
5134 || TREE_CODE_CLASS (TREE_CODE (cond)) == tcc_comparison);
5136 if (TREE_CODE (cond) == SSA_NAME)
5142 retval = compare_name_with_value (NE_EXPR, cond, boolean_false_node,
5146 value_range_t *vr = get_value_range (cond);
5147 retval = compare_range_with_value (NE_EXPR, vr, boolean_false_node,
5151 /* If COND has a known boolean range, return it. */
5155 /* Otherwise, if COND has a symbolic range of exactly one value,
5157 vr = get_value_range (cond);
5158 if (vr->type == VR_RANGE && vr->min == vr->max)
5163 tree op0 = TREE_OPERAND (cond, 0);
5164 tree op1 = TREE_OPERAND (cond, 1);
5166 /* We only deal with integral and pointer types. */
5167 if (!INTEGRAL_TYPE_P (TREE_TYPE (op0))
5168 && !POINTER_TYPE_P (TREE_TYPE (op0)))
5173 if (TREE_CODE (op0) == SSA_NAME && TREE_CODE (op1) == SSA_NAME)
5174 return compare_names (TREE_CODE (cond), op0, op1,
5176 else if (TREE_CODE (op0) == SSA_NAME)
5177 return compare_name_with_value (TREE_CODE (cond), op0, op1,
5179 else if (TREE_CODE (op1) == SSA_NAME)
5180 return (compare_name_with_value
5181 (swap_tree_comparison (TREE_CODE (cond)), op1, op0,
5182 strict_overflow_p));
5186 value_range_t *vr0, *vr1;
5188 vr0 = (TREE_CODE (op0) == SSA_NAME) ? get_value_range (op0) : NULL;
5189 vr1 = (TREE_CODE (op1) == SSA_NAME) ? get_value_range (op1) : NULL;
5192 return compare_ranges (TREE_CODE (cond), vr0, vr1,
5194 else if (vr0 && vr1 == NULL)
5195 return compare_range_with_value (TREE_CODE (cond), vr0, op1,
5197 else if (vr0 == NULL && vr1)
5198 return (compare_range_with_value
5199 (swap_tree_comparison (TREE_CODE (cond)), vr1, op0,
5200 strict_overflow_p));
5204 /* Anything else cannot be computed statically. */
5208 /* Given COND within STMT, try to simplify it based on value range
5209 information. Return NULL if the conditional can not be evaluated.
5210 The ranges of all the names equivalent with the operands in COND
5211 will be used when trying to compute the value. If the result is
5212 based on undefined signed overflow, issue a warning if
5216 vrp_evaluate_conditional (tree cond, tree stmt)
5222 ret = vrp_evaluate_conditional_warnv (cond, true, &sop);
5226 enum warn_strict_overflow_code wc;
5227 const char* warnmsg;
5229 if (is_gimple_min_invariant (ret))
5231 wc = WARN_STRICT_OVERFLOW_CONDITIONAL;
5232 warnmsg = G_("assuming signed overflow does not occur when "
5233 "simplifying conditional to constant");
5237 wc = WARN_STRICT_OVERFLOW_COMPARISON;
5238 warnmsg = G_("assuming signed overflow does not occur when "
5239 "simplifying conditional");
5242 if (issue_strict_overflow_warning (wc))
5246 if (!EXPR_HAS_LOCATION (stmt))
5247 locus = input_location;
5249 locus = EXPR_LOCATION (stmt);
5250 warning (OPT_Wstrict_overflow, "%H%s", &locus, warnmsg);
5254 if (warn_type_limits
5256 && TREE_CODE_CLASS (TREE_CODE (cond)) == tcc_comparison)
5258 /* If the comparison is being folded and the operand on the LHS
5259 is being compared against a constant value that is outside of
5260 the natural range of OP0's type, then the predicate will
5261 always fold regardless of the value of OP0. If -Wtype-limits
5262 was specified, emit a warning. */
5263 const char *warnmsg = NULL;
5264 tree op0 = TREE_OPERAND (cond, 0);
5265 tree op1 = TREE_OPERAND (cond, 1);
5266 tree type = TREE_TYPE (op0);
5267 value_range_t *vr0 = get_value_range (op0);
5269 if (vr0->type != VR_VARYING
5270 && INTEGRAL_TYPE_P (type)
5271 && vrp_val_is_min (vr0->min)
5272 && vrp_val_is_max (vr0->max)
5273 && is_gimple_min_invariant (op1))
5275 if (integer_zerop (ret))
5276 warnmsg = G_("comparison always false due to limited range of "
5279 warnmsg = G_("comparison always true due to limited range of "
5287 if (!EXPR_HAS_LOCATION (stmt))
5288 locus = input_location;
5290 locus = EXPR_LOCATION (stmt);
5292 warning (OPT_Wtype_limits, "%H%s", &locus, warnmsg);
5300 /* Visit conditional statement STMT. If we can determine which edge
5301 will be taken out of STMT's basic block, record it in
5302 *TAKEN_EDGE_P and return SSA_PROP_INTERESTING. Otherwise, return
5303 SSA_PROP_VARYING. */
5305 static enum ssa_prop_result
5306 vrp_visit_cond_stmt (tree stmt, edge *taken_edge_p)
5311 *taken_edge_p = NULL;
5313 /* FIXME. Handle SWITCH_EXPRs. */
5314 if (TREE_CODE (stmt) == SWITCH_EXPR)
5315 return SSA_PROP_VARYING;
5317 cond = COND_EXPR_COND (stmt);
5319 if (dump_file && (dump_flags & TDF_DETAILS))
5324 fprintf (dump_file, "\nVisiting conditional with predicate: ");
5325 print_generic_expr (dump_file, cond, 0);
5326 fprintf (dump_file, "\nWith known ranges\n");
5328 FOR_EACH_SSA_TREE_OPERAND (use, stmt, i, SSA_OP_USE)
5330 fprintf (dump_file, "\t");
5331 print_generic_expr (dump_file, use, 0);
5332 fprintf (dump_file, ": ");
5333 dump_value_range (dump_file, vr_value[SSA_NAME_VERSION (use)]);
5336 fprintf (dump_file, "\n");
5339 /* Compute the value of the predicate COND by checking the known
5340 ranges of each of its operands.
5342 Note that we cannot evaluate all the equivalent ranges here
5343 because those ranges may not yet be final and with the current
5344 propagation strategy, we cannot determine when the value ranges
5345 of the names in the equivalence set have changed.
5347 For instance, given the following code fragment
5351 i_14 = ASSERT_EXPR <i_5, i_5 != 0>
5355 Assume that on the first visit to i_14, i_5 has the temporary
5356 range [8, 8] because the second argument to the PHI function is
5357 not yet executable. We derive the range ~[0, 0] for i_14 and the
5358 equivalence set { i_5 }. So, when we visit 'if (i_14 == 1)' for
5359 the first time, since i_14 is equivalent to the range [8, 8], we
5360 determine that the predicate is always false.
5362 On the next round of propagation, i_13 is determined to be
5363 VARYING, which causes i_5 to drop down to VARYING. So, another
5364 visit to i_14 is scheduled. In this second visit, we compute the
5365 exact same range and equivalence set for i_14, namely ~[0, 0] and
5366 { i_5 }. But we did not have the previous range for i_5
5367 registered, so vrp_visit_assignment thinks that the range for
5368 i_14 has not changed. Therefore, the predicate 'if (i_14 == 1)'
5369 is not visited again, which stops propagation from visiting
5370 statements in the THEN clause of that if().
5372 To properly fix this we would need to keep the previous range
5373 value for the names in the equivalence set. This way we would've
5374 discovered that from one visit to the other i_5 changed from
5375 range [8, 8] to VR_VARYING.
5377 However, fixing this apparent limitation may not be worth the
5378 additional checking. Testing on several code bases (GCC, DLV,
5379 MICO, TRAMP3D and SPEC2000) showed that doing this results in
5380 4 more predicates folded in SPEC. */
5382 val = vrp_evaluate_conditional_warnv (cond, false, &sop);
5386 *taken_edge_p = find_taken_edge (bb_for_stmt (stmt), val);
5389 if (dump_file && (dump_flags & TDF_DETAILS))
5391 "\nIgnoring predicate evaluation because "
5392 "it assumes that signed overflow is undefined");
5397 if (dump_file && (dump_flags & TDF_DETAILS))
5399 fprintf (dump_file, "\nPredicate evaluates to: ");
5400 if (val == NULL_TREE)
5401 fprintf (dump_file, "DON'T KNOW\n");
5403 print_generic_stmt (dump_file, val, 0);
5406 return (*taken_edge_p) ? SSA_PROP_INTERESTING : SSA_PROP_VARYING;
5410 /* Evaluate statement STMT. If the statement produces a useful range,
5411 return SSA_PROP_INTERESTING and record the SSA name with the
5412 interesting range into *OUTPUT_P.
5414 If STMT is a conditional branch and we can determine its truth
5415 value, the taken edge is recorded in *TAKEN_EDGE_P.
5417 If STMT produces a varying value, return SSA_PROP_VARYING. */
5419 static enum ssa_prop_result
5420 vrp_visit_stmt (tree stmt, edge *taken_edge_p, tree *output_p)
5426 if (dump_file && (dump_flags & TDF_DETAILS))
5428 fprintf (dump_file, "\nVisiting statement:\n");
5429 print_generic_stmt (dump_file, stmt, dump_flags);
5430 fprintf (dump_file, "\n");
5433 ann = stmt_ann (stmt);
5434 if (TREE_CODE (stmt) == GIMPLE_MODIFY_STMT)
5436 tree rhs = GIMPLE_STMT_OPERAND (stmt, 1);
5438 /* In general, assignments with virtual operands are not useful
5439 for deriving ranges, with the obvious exception of calls to
5440 builtin functions. */
5441 if ((TREE_CODE (rhs) == CALL_EXPR
5442 && TREE_CODE (CALL_EXPR_FN (rhs)) == ADDR_EXPR
5443 && DECL_P (TREE_OPERAND (CALL_EXPR_FN (rhs), 0))
5444 && DECL_IS_BUILTIN (TREE_OPERAND (CALL_EXPR_FN (rhs), 0)))
5445 || ZERO_SSA_OPERANDS (stmt, SSA_OP_ALL_VIRTUALS))
5446 return vrp_visit_assignment (stmt, output_p);
5448 else if (TREE_CODE (stmt) == COND_EXPR || TREE_CODE (stmt) == SWITCH_EXPR)
5449 return vrp_visit_cond_stmt (stmt, taken_edge_p);
5451 /* All other statements produce nothing of interest for VRP, so mark
5452 their outputs varying and prevent further simulation. */
5453 FOR_EACH_SSA_TREE_OPERAND (def, stmt, iter, SSA_OP_DEF)
5454 set_value_range_to_varying (get_value_range (def));
5456 return SSA_PROP_VARYING;
5460 /* Meet operation for value ranges. Given two value ranges VR0 and
5461 VR1, store in VR0 a range that contains both VR0 and VR1. This
5462 may not be the smallest possible such range. */
5465 vrp_meet (value_range_t *vr0, value_range_t *vr1)
5467 if (vr0->type == VR_UNDEFINED)
5469 copy_value_range (vr0, vr1);
5473 if (vr1->type == VR_UNDEFINED)
5475 /* Nothing to do. VR0 already has the resulting range. */
5479 if (vr0->type == VR_VARYING)
5481 /* Nothing to do. VR0 already has the resulting range. */
5485 if (vr1->type == VR_VARYING)
5487 set_value_range_to_varying (vr0);
5491 if (vr0->type == VR_RANGE && vr1->type == VR_RANGE)
5496 /* Compute the convex hull of the ranges. The lower limit of
5497 the new range is the minimum of the two ranges. If they
5498 cannot be compared, then give up. */
5499 cmp = compare_values (vr0->min, vr1->min);
5500 if (cmp == 0 || cmp == 1)
5507 /* Similarly, the upper limit of the new range is the maximum
5508 of the two ranges. If they cannot be compared, then
5510 cmp = compare_values (vr0->max, vr1->max);
5511 if (cmp == 0 || cmp == -1)
5518 /* Check for useless ranges. */
5519 if (INTEGRAL_TYPE_P (TREE_TYPE (min))
5520 && ((vrp_val_is_min (min) || is_overflow_infinity (min))
5521 && (vrp_val_is_max (max) || is_overflow_infinity (max))))
5524 /* The resulting set of equivalences is the intersection of
5526 if (vr0->equiv && vr1->equiv && vr0->equiv != vr1->equiv)
5527 bitmap_and_into (vr0->equiv, vr1->equiv);
5528 else if (vr0->equiv && !vr1->equiv)
5529 bitmap_clear (vr0->equiv);
5531 set_value_range (vr0, vr0->type, min, max, vr0->equiv);
5533 else if (vr0->type == VR_ANTI_RANGE && vr1->type == VR_ANTI_RANGE)
5535 /* Two anti-ranges meet only if their complements intersect.
5536 Only handle the case of identical ranges. */
5537 if (compare_values (vr0->min, vr1->min) == 0
5538 && compare_values (vr0->max, vr1->max) == 0
5539 && compare_values (vr0->min, vr0->max) == 0)
5541 /* The resulting set of equivalences is the intersection of
5543 if (vr0->equiv && vr1->equiv && vr0->equiv != vr1->equiv)
5544 bitmap_and_into (vr0->equiv, vr1->equiv);
5545 else if (vr0->equiv && !vr1->equiv)
5546 bitmap_clear (vr0->equiv);
5551 else if (vr0->type == VR_ANTI_RANGE || vr1->type == VR_ANTI_RANGE)
5553 /* For a numeric range [VAL1, VAL2] and an anti-range ~[VAL3, VAL4],
5554 only handle the case where the ranges have an empty intersection.
5555 The result of the meet operation is the anti-range. */
5556 if (!symbolic_range_p (vr0)
5557 && !symbolic_range_p (vr1)
5558 && !value_ranges_intersect_p (vr0, vr1))
5560 /* Copy most of VR1 into VR0. Don't copy VR1's equivalence
5561 set. We need to compute the intersection of the two
5562 equivalence sets. */
5563 if (vr1->type == VR_ANTI_RANGE)
5564 set_value_range (vr0, vr1->type, vr1->min, vr1->max, vr0->equiv);
5566 /* The resulting set of equivalences is the intersection of
5568 if (vr0->equiv && vr1->equiv && vr0->equiv != vr1->equiv)
5569 bitmap_and_into (vr0->equiv, vr1->equiv);
5570 else if (vr0->equiv && !vr1->equiv)
5571 bitmap_clear (vr0->equiv);
5582 /* Failed to find an efficient meet. Before giving up and setting
5583 the result to VARYING, see if we can at least derive a useful
5584 anti-range. FIXME, all this nonsense about distinguishing
5585 anti-ranges from ranges is necessary because of the odd
5586 semantics of range_includes_zero_p and friends. */
5587 if (!symbolic_range_p (vr0)
5588 && ((vr0->type == VR_RANGE && !range_includes_zero_p (vr0))
5589 || (vr0->type == VR_ANTI_RANGE && range_includes_zero_p (vr0)))
5590 && !symbolic_range_p (vr1)
5591 && ((vr1->type == VR_RANGE && !range_includes_zero_p (vr1))
5592 || (vr1->type == VR_ANTI_RANGE && range_includes_zero_p (vr1))))
5594 set_value_range_to_nonnull (vr0, TREE_TYPE (vr0->min));
5596 /* Since this meet operation did not result from the meeting of
5597 two equivalent names, VR0 cannot have any equivalences. */
5599 bitmap_clear (vr0->equiv);
5602 set_value_range_to_varying (vr0);
5606 /* Visit all arguments for PHI node PHI that flow through executable
5607 edges. If a valid value range can be derived from all the incoming
5608 value ranges, set a new range for the LHS of PHI. */
5610 static enum ssa_prop_result
5611 vrp_visit_phi_node (tree phi)
5614 tree lhs = PHI_RESULT (phi);
5615 value_range_t *lhs_vr = get_value_range (lhs);
5616 value_range_t vr_result = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
5617 int edges, old_edges;
5619 copy_value_range (&vr_result, lhs_vr);
5621 if (dump_file && (dump_flags & TDF_DETAILS))
5623 fprintf (dump_file, "\nVisiting PHI node: ");
5624 print_generic_expr (dump_file, phi, dump_flags);
5628 for (i = 0; i < PHI_NUM_ARGS (phi); i++)
5630 edge e = PHI_ARG_EDGE (phi, i);
5632 if (dump_file && (dump_flags & TDF_DETAILS))
5635 "\n Argument #%d (%d -> %d %sexecutable)\n",
5636 i, e->src->index, e->dest->index,
5637 (e->flags & EDGE_EXECUTABLE) ? "" : "not ");
5640 if (e->flags & EDGE_EXECUTABLE)
5642 tree arg = PHI_ARG_DEF (phi, i);
5643 value_range_t vr_arg;
5647 if (TREE_CODE (arg) == SSA_NAME)
5649 vr_arg = *(get_value_range (arg));
5653 if (is_overflow_infinity (arg))
5655 arg = copy_node (arg);
5656 TREE_OVERFLOW (arg) = 0;
5659 vr_arg.type = VR_RANGE;
5662 vr_arg.equiv = NULL;
5665 if (dump_file && (dump_flags & TDF_DETAILS))
5667 fprintf (dump_file, "\t");
5668 print_generic_expr (dump_file, arg, dump_flags);
5669 fprintf (dump_file, "\n\tValue: ");
5670 dump_value_range (dump_file, &vr_arg);
5671 fprintf (dump_file, "\n");
5674 vrp_meet (&vr_result, &vr_arg);
5676 if (vr_result.type == VR_VARYING)
5681 if (vr_result.type == VR_VARYING)
5684 old_edges = vr_phi_edge_counts[SSA_NAME_VERSION (lhs)];
5685 vr_phi_edge_counts[SSA_NAME_VERSION (lhs)] = edges;
5687 /* To prevent infinite iterations in the algorithm, derive ranges
5688 when the new value is slightly bigger or smaller than the
5689 previous one. We don't do this if we have seen a new executable
5690 edge; this helps us avoid an overflow infinity for conditionals
5691 which are not in a loop. */
5692 if (lhs_vr->type == VR_RANGE && vr_result.type == VR_RANGE
5693 && edges <= old_edges)
5695 if (!POINTER_TYPE_P (TREE_TYPE (lhs)))
5697 int cmp_min = compare_values (lhs_vr->min, vr_result.min);
5698 int cmp_max = compare_values (lhs_vr->max, vr_result.max);
5700 /* If the new minimum is smaller or larger than the previous
5701 one, go all the way to -INF. In the first case, to avoid
5702 iterating millions of times to reach -INF, and in the
5703 other case to avoid infinite bouncing between different
5705 if (cmp_min > 0 || cmp_min < 0)
5707 /* If we will end up with a (-INF, +INF) range, set it
5709 if (vrp_val_is_max (vr_result.max))
5712 if (!needs_overflow_infinity (TREE_TYPE (vr_result.min))
5713 || !vrp_var_may_overflow (lhs, phi))
5714 vr_result.min = TYPE_MIN_VALUE (TREE_TYPE (vr_result.min));
5715 else if (supports_overflow_infinity (TREE_TYPE (vr_result.min)))
5717 negative_overflow_infinity (TREE_TYPE (vr_result.min));
5722 /* Similarly, if the new maximum is smaller or larger than
5723 the previous one, go all the way to +INF. */
5724 if (cmp_max < 0 || cmp_max > 0)
5726 /* If we will end up with a (-INF, +INF) range, set it
5728 if (vrp_val_is_min (vr_result.min))
5731 if (!needs_overflow_infinity (TREE_TYPE (vr_result.max))
5732 || !vrp_var_may_overflow (lhs, phi))
5733 vr_result.max = TYPE_MAX_VALUE (TREE_TYPE (vr_result.max));
5734 else if (supports_overflow_infinity (TREE_TYPE (vr_result.max)))
5736 positive_overflow_infinity (TREE_TYPE (vr_result.max));
5743 /* If the new range is different than the previous value, keep
5745 if (update_value_range (lhs, &vr_result))
5746 return SSA_PROP_INTERESTING;
5748 /* Nothing changed, don't add outgoing edges. */
5749 return SSA_PROP_NOT_INTERESTING;
5751 /* No match found. Set the LHS to VARYING. */
5753 set_value_range_to_varying (lhs_vr);
5754 return SSA_PROP_VARYING;
5757 /* Simplify a division or modulo operator to a right shift or
5758 bitwise and if the first operand is unsigned or is greater
5759 than zero and the second operand is an exact power of two. */
5762 simplify_div_or_mod_using_ranges (tree stmt, tree rhs, enum tree_code rhs_code)
5765 tree op = TREE_OPERAND (rhs, 0);
5766 value_range_t *vr = get_value_range (TREE_OPERAND (rhs, 0));
5768 if (TYPE_UNSIGNED (TREE_TYPE (op)))
5770 val = integer_one_node;
5776 val = compare_range_with_value (GE_EXPR, vr, integer_zero_node, &sop);
5780 && integer_onep (val)
5781 && issue_strict_overflow_warning (WARN_STRICT_OVERFLOW_MISC))
5785 if (!EXPR_HAS_LOCATION (stmt))
5786 locus = input_location;
5788 locus = EXPR_LOCATION (stmt);
5789 warning (OPT_Wstrict_overflow,
5790 ("%Hassuming signed overflow does not occur when "
5791 "simplifying / or %% to >> or &"),
5796 if (val && integer_onep (val))
5799 tree op0 = TREE_OPERAND (rhs, 0);
5800 tree op1 = TREE_OPERAND (rhs, 1);
5802 if (rhs_code == TRUNC_DIV_EXPR)
5804 t = build_int_cst (NULL_TREE, tree_log2 (op1));
5805 t = build2 (RSHIFT_EXPR, TREE_TYPE (op0), op0, t);
5809 t = build_int_cst (TREE_TYPE (op1), 1);
5810 t = int_const_binop (MINUS_EXPR, op1, t, 0);
5811 t = fold_convert (TREE_TYPE (op0), t);
5812 t = build2 (BIT_AND_EXPR, TREE_TYPE (op0), op0, t);
5815 GIMPLE_STMT_OPERAND (stmt, 1) = t;
5820 /* If the operand to an ABS_EXPR is >= 0, then eliminate the
5821 ABS_EXPR. If the operand is <= 0, then simplify the
5822 ABS_EXPR into a NEGATE_EXPR. */
5825 simplify_abs_using_ranges (tree stmt, tree rhs)
5828 tree op = TREE_OPERAND (rhs, 0);
5829 tree type = TREE_TYPE (op);
5830 value_range_t *vr = get_value_range (TREE_OPERAND (rhs, 0));
5832 if (TYPE_UNSIGNED (type))
5834 val = integer_zero_node;
5840 val = compare_range_with_value (LE_EXPR, vr, integer_zero_node, &sop);
5844 val = compare_range_with_value (GE_EXPR, vr, integer_zero_node,
5849 if (integer_zerop (val))
5850 val = integer_one_node;
5851 else if (integer_onep (val))
5852 val = integer_zero_node;
5857 && (integer_onep (val) || integer_zerop (val)))
5861 if (sop && issue_strict_overflow_warning (WARN_STRICT_OVERFLOW_MISC))
5865 if (!EXPR_HAS_LOCATION (stmt))
5866 locus = input_location;
5868 locus = EXPR_LOCATION (stmt);
5869 warning (OPT_Wstrict_overflow,
5870 ("%Hassuming signed overflow does not occur when "
5871 "simplifying abs (X) to X or -X"),
5875 if (integer_onep (val))
5876 t = build1 (NEGATE_EXPR, TREE_TYPE (op), op);
5880 GIMPLE_STMT_OPERAND (stmt, 1) = t;
5886 /* We are comparing trees OP0 and OP1 using COND_CODE. OP0 has
5887 a known value range VR.
5889 If there is one and only one value which will satisfy the
5890 conditional, then return that value. Else return NULL. */
5893 test_for_singularity (enum tree_code cond_code, tree op0,
5894 tree op1, value_range_t *vr)
5899 /* Extract minimum/maximum values which satisfy the
5900 the conditional as it was written. */
5901 if (cond_code == LE_EXPR || cond_code == LT_EXPR)
5903 /* This should not be negative infinity; there is no overflow
5905 min = TYPE_MIN_VALUE (TREE_TYPE (op0));
5908 if (cond_code == LT_EXPR && !is_overflow_infinity (max))
5910 tree one = build_int_cst (TREE_TYPE (op0), 1);
5911 max = fold_build2 (MINUS_EXPR, TREE_TYPE (op0), max, one);
5913 TREE_NO_WARNING (max) = 1;
5916 else if (cond_code == GE_EXPR || cond_code == GT_EXPR)
5918 /* This should not be positive infinity; there is no overflow
5920 max = TYPE_MAX_VALUE (TREE_TYPE (op0));
5923 if (cond_code == GT_EXPR && !is_overflow_infinity (min))
5925 tree one = build_int_cst (TREE_TYPE (op0), 1);
5926 min = fold_build2 (PLUS_EXPR, TREE_TYPE (op0), min, one);
5928 TREE_NO_WARNING (min) = 1;
5932 /* Now refine the minimum and maximum values using any
5933 value range information we have for op0. */
5936 if (compare_values (vr->min, min) == -1)
5940 if (compare_values (vr->max, max) == 1)
5945 /* If the new min/max values have converged to a single value,
5946 then there is only one value which can satisfy the condition,
5947 return that value. */
5948 if (operand_equal_p (min, max, 0) && is_gimple_min_invariant (min))
5954 /* Simplify a conditional using a relational operator to an equality
5955 test if the range information indicates only one value can satisfy
5956 the original conditional. */
5959 simplify_cond_using_ranges (tree stmt)
5961 tree cond = COND_EXPR_COND (stmt);
5962 tree op0 = TREE_OPERAND (cond, 0);
5963 tree op1 = TREE_OPERAND (cond, 1);
5964 enum tree_code cond_code = TREE_CODE (cond);
5966 if (cond_code != NE_EXPR
5967 && cond_code != EQ_EXPR
5968 && TREE_CODE (op0) == SSA_NAME
5969 && INTEGRAL_TYPE_P (TREE_TYPE (op0))
5970 && is_gimple_min_invariant (op1))
5972 value_range_t *vr = get_value_range (op0);
5974 /* If we have range information for OP0, then we might be
5975 able to simplify this conditional. */
5976 if (vr->type == VR_RANGE)
5978 tree new = test_for_singularity (cond_code, op0, op1, vr);
5984 fprintf (dump_file, "Simplified relational ");
5985 print_generic_expr (dump_file, cond, 0);
5986 fprintf (dump_file, " into ");
5989 COND_EXPR_COND (stmt)
5990 = build2 (EQ_EXPR, boolean_type_node, op0, new);
5995 print_generic_expr (dump_file, COND_EXPR_COND (stmt), 0);
5996 fprintf (dump_file, "\n");
6002 /* Try again after inverting the condition. We only deal
6003 with integral types here, so no need to worry about
6004 issues with inverting FP comparisons. */
6005 cond_code = invert_tree_comparison (cond_code, false);
6006 new = test_for_singularity (cond_code, op0, op1, vr);
6012 fprintf (dump_file, "Simplified relational ");
6013 print_generic_expr (dump_file, cond, 0);
6014 fprintf (dump_file, " into ");
6017 COND_EXPR_COND (stmt)
6018 = build2 (NE_EXPR, boolean_type_node, op0, new);
6023 print_generic_expr (dump_file, COND_EXPR_COND (stmt), 0);
6024 fprintf (dump_file, "\n");
6033 /* Simplify STMT using ranges if possible. */
6036 simplify_stmt_using_ranges (tree stmt)
6038 if (TREE_CODE (stmt) == GIMPLE_MODIFY_STMT)
6040 tree rhs = GIMPLE_STMT_OPERAND (stmt, 1);
6041 enum tree_code rhs_code = TREE_CODE (rhs);
6043 /* Transform TRUNC_DIV_EXPR and TRUNC_MOD_EXPR into RSHIFT_EXPR
6044 and BIT_AND_EXPR respectively if the first operand is greater
6045 than zero and the second operand is an exact power of two. */
6046 if ((rhs_code == TRUNC_DIV_EXPR || rhs_code == TRUNC_MOD_EXPR)
6047 && INTEGRAL_TYPE_P (TREE_TYPE (TREE_OPERAND (rhs, 0)))
6048 && integer_pow2p (TREE_OPERAND (rhs, 1)))
6049 simplify_div_or_mod_using_ranges (stmt, rhs, rhs_code);
6051 /* Transform ABS (X) into X or -X as appropriate. */
6052 if (rhs_code == ABS_EXPR
6053 && TREE_CODE (TREE_OPERAND (rhs, 0)) == SSA_NAME
6054 && INTEGRAL_TYPE_P (TREE_TYPE (TREE_OPERAND (rhs, 0))))
6055 simplify_abs_using_ranges (stmt, rhs);
6057 else if (TREE_CODE (stmt) == COND_EXPR
6058 && COMPARISON_CLASS_P (COND_EXPR_COND (stmt)))
6060 simplify_cond_using_ranges (stmt);
6064 /* Stack of dest,src equivalency pairs that need to be restored after
6065 each attempt to thread a block's incoming edge to an outgoing edge.
6067 A NULL entry is used to mark the end of pairs which need to be
6069 static VEC(tree,heap) *stack;
6071 /* A trivial wrapper so that we can present the generic jump threading
6072 code with a simple API for simplifying statements. STMT is the
6073 statement we want to simplify, WITHIN_STMT provides the location
6074 for any overflow warnings. */
6077 simplify_stmt_for_jump_threading (tree stmt, tree within_stmt)
6079 /* We only use VRP information to simplify conditionals. This is
6080 overly conservative, but it's unclear if doing more would be
6081 worth the compile time cost. */
6082 if (TREE_CODE (stmt) != COND_EXPR)
6085 return vrp_evaluate_conditional (COND_EXPR_COND (stmt), within_stmt);
6088 /* Blocks which have more than one predecessor and more than
6089 one successor present jump threading opportunities. ie,
6090 when the block is reached from a specific predecessor, we
6091 may be able to determine which of the outgoing edges will
6092 be traversed. When this optimization applies, we are able
6093 to avoid conditionals at runtime and we may expose secondary
6094 optimization opportunities.
6096 This routine is effectively a driver for the generic jump
6097 threading code. It basically just presents the generic code
6098 with edges that may be suitable for jump threading.
6100 Unlike DOM, we do not iterate VRP if jump threading was successful.
6101 While iterating may expose new opportunities for VRP, it is expected
6102 those opportunities would be very limited and the compile time cost
6103 to expose those opportunities would be significant.
6105 As jump threading opportunities are discovered, they are registered
6106 for later realization. */
6109 identify_jump_threads (void)
6114 /* Ugh. When substituting values earlier in this pass we can
6115 wipe the dominance information. So rebuild the dominator
6116 information as we need it within the jump threading code. */
6117 calculate_dominance_info (CDI_DOMINATORS);
6119 /* We do not allow VRP information to be used for jump threading
6120 across a back edge in the CFG. Otherwise it becomes too
6121 difficult to avoid eliminating loop exit tests. Of course
6122 EDGE_DFS_BACK is not accurate at this time so we have to
6124 mark_dfs_back_edges ();
6126 /* Allocate our unwinder stack to unwind any temporary equivalences
6127 that might be recorded. */
6128 stack = VEC_alloc (tree, heap, 20);
6130 /* To avoid lots of silly node creation, we create a single
6131 conditional and just modify it in-place when attempting to
6133 dummy = build2 (EQ_EXPR, boolean_type_node, NULL, NULL);
6134 dummy = build3 (COND_EXPR, void_type_node, dummy, NULL, NULL);
6136 /* Walk through all the blocks finding those which present a
6137 potential jump threading opportunity. We could set this up
6138 as a dominator walker and record data during the walk, but
6139 I doubt it's worth the effort for the classes of jump
6140 threading opportunities we are trying to identify at this
6141 point in compilation. */
6146 /* If the generic jump threading code does not find this block
6147 interesting, then there is nothing to do. */
6148 if (! potentially_threadable_block (bb))
6151 /* We only care about blocks ending in a COND_EXPR. While there
6152 may be some value in handling SWITCH_EXPR here, I doubt it's
6153 terribly important. */
6154 last = bsi_stmt (bsi_last (bb));
6155 if (TREE_CODE (last) != COND_EXPR)
6158 /* We're basically looking for any kind of conditional with
6159 integral type arguments. */
6160 cond = COND_EXPR_COND (last);
6161 if ((TREE_CODE (cond) == SSA_NAME
6162 && INTEGRAL_TYPE_P (TREE_TYPE (cond)))
6163 || (COMPARISON_CLASS_P (cond)
6164 && TREE_CODE (TREE_OPERAND (cond, 0)) == SSA_NAME
6165 && INTEGRAL_TYPE_P (TREE_TYPE (TREE_OPERAND (cond, 0)))
6166 && (TREE_CODE (TREE_OPERAND (cond, 1)) == SSA_NAME
6167 || is_gimple_min_invariant (TREE_OPERAND (cond, 1)))
6168 && INTEGRAL_TYPE_P (TREE_TYPE (TREE_OPERAND (cond, 1)))))
6173 /* We've got a block with multiple predecessors and multiple
6174 successors which also ends in a suitable conditional. For
6175 each predecessor, see if we can thread it to a specific
6177 FOR_EACH_EDGE (e, ei, bb->preds)
6179 /* Do not thread across back edges or abnormal edges
6181 if (e->flags & (EDGE_DFS_BACK | EDGE_COMPLEX))
6184 thread_across_edge (dummy, e, true,
6186 simplify_stmt_for_jump_threading);
6191 /* We do not actually update the CFG or SSA graphs at this point as
6192 ASSERT_EXPRs are still in the IL and cfg cleanup code does not yet
6193 handle ASSERT_EXPRs gracefully. */
6196 /* We identified all the jump threading opportunities earlier, but could
6197 not transform the CFG at that time. This routine transforms the
6198 CFG and arranges for the dominator tree to be rebuilt if necessary.
6200 Note the SSA graph update will occur during the normal TODO
6201 processing by the pass manager. */
6203 finalize_jump_threads (void)
6205 thread_through_all_blocks (false);
6206 VEC_free (tree, heap, stack);
6210 /* Traverse all the blocks folding conditionals with known ranges. */
6216 prop_value_t *single_val_range;
6217 bool do_value_subst_p;
6221 fprintf (dump_file, "\nValue ranges after VRP:\n\n");
6222 dump_all_value_ranges (dump_file);
6223 fprintf (dump_file, "\n");
6226 /* We may have ended with ranges that have exactly one value. Those
6227 values can be substituted as any other copy/const propagated
6228 value using substitute_and_fold. */
6229 single_val_range = XCNEWVEC (prop_value_t, num_ssa_names);
6231 do_value_subst_p = false;
6232 for (i = 0; i < num_ssa_names; i++)
6234 && vr_value[i]->type == VR_RANGE
6235 && vr_value[i]->min == vr_value[i]->max)
6237 single_val_range[i].value = vr_value[i]->min;
6238 do_value_subst_p = true;
6241 if (!do_value_subst_p)
6243 /* We found no single-valued ranges, don't waste time trying to
6244 do single value substitution in substitute_and_fold. */
6245 free (single_val_range);
6246 single_val_range = NULL;
6249 substitute_and_fold (single_val_range, true);
6251 if (warn_array_bounds)
6252 check_all_array_refs ();
6254 /* We must identify jump threading opportunities before we release
6255 the datastructures built by VRP. */
6256 identify_jump_threads ();
6258 /* Free allocated memory. */
6259 for (i = 0; i < num_ssa_names; i++)
6262 BITMAP_FREE (vr_value[i]->equiv);
6266 free (single_val_range);
6268 free (vr_phi_edge_counts);
6270 /* So that we can distinguish between VRP data being available
6271 and not available. */
6273 vr_phi_edge_counts = NULL;
6276 /* Calculates number of iterations for all loops, to ensure that they are
6280 record_numbers_of_iterations (void)
6285 FOR_EACH_LOOP (li, loop, 0)
6287 number_of_latch_executions (loop);
6291 /* Main entry point to VRP (Value Range Propagation). This pass is
6292 loosely based on J. R. C. Patterson, ``Accurate Static Branch
6293 Prediction by Value Range Propagation,'' in SIGPLAN Conference on
6294 Programming Language Design and Implementation, pp. 67-78, 1995.
6295 Also available at http://citeseer.ist.psu.edu/patterson95accurate.html
6297 This is essentially an SSA-CCP pass modified to deal with ranges
6298 instead of constants.
6300 While propagating ranges, we may find that two or more SSA name
6301 have equivalent, though distinct ranges. For instance,
6304 2 p_4 = ASSERT_EXPR <p_3, p_3 != 0>
6306 4 p_5 = ASSERT_EXPR <p_4, p_4 == q_2>;
6310 In the code above, pointer p_5 has range [q_2, q_2], but from the
6311 code we can also determine that p_5 cannot be NULL and, if q_2 had
6312 a non-varying range, p_5's range should also be compatible with it.
6314 These equivalences are created by two expressions: ASSERT_EXPR and
6315 copy operations. Since p_5 is an assertion on p_4, and p_4 was the
6316 result of another assertion, then we can use the fact that p_5 and
6317 p_4 are equivalent when evaluating p_5's range.
6319 Together with value ranges, we also propagate these equivalences
6320 between names so that we can take advantage of information from
6321 multiple ranges when doing final replacement. Note that this
6322 equivalency relation is transitive but not symmetric.
6324 In the example above, p_5 is equivalent to p_4, q_2 and p_3, but we
6325 cannot assert that q_2 is equivalent to p_5 because q_2 may be used
6326 in contexts where that assertion does not hold (e.g., in line 6).
6328 TODO, the main difference between this pass and Patterson's is that
6329 we do not propagate edge probabilities. We only compute whether
6330 edges can be taken or not. That is, instead of having a spectrum
6331 of jump probabilities between 0 and 1, we only deal with 0, 1 and
6332 DON'T KNOW. In the future, it may be worthwhile to propagate
6333 probabilities to aid branch prediction. */
6338 loop_optimizer_init (LOOPS_NORMAL | LOOPS_HAVE_RECORDED_EXITS);
6339 rewrite_into_loop_closed_ssa (NULL, TODO_update_ssa);
6342 insert_range_assertions ();
6344 /* Compute the # of iterations for each loop before we start the VRP
6345 analysis. The value ranges determined by VRP are used in expression
6346 simplification, that is also used by the # of iterations analysis.
6347 However, in the middle of the VRP analysis, the value ranges do not take
6348 all the possible paths in CFG into account, so they do not have to be
6349 correct, and the # of iterations analysis can obtain wrong results.
6350 This is a problem, since the results of the # of iterations analysis
6351 are cached, so these mistakes would not be corrected when the value
6352 ranges are corrected. */
6353 record_numbers_of_iterations ();
6356 ssa_propagate (vrp_visit_stmt, vrp_visit_phi_node);
6359 /* ASSERT_EXPRs must be removed before finalizing jump threads
6360 as finalizing jump threads calls the CFG cleanup code which
6361 does not properly handle ASSERT_EXPRs. */
6362 remove_range_assertions ();
6364 /* If we exposed any new variables, go ahead and put them into
6365 SSA form now, before we handle jump threading. This simplifies
6366 interactions between rewriting of _DECL nodes into SSA form
6367 and rewriting SSA_NAME nodes into SSA form after block
6368 duplication and CFG manipulation. */
6369 update_ssa (TODO_update_ssa);
6371 finalize_jump_threads ();
6373 loop_optimizer_finalize ();
6381 return flag_tree_vrp != 0;
6384 struct gimple_opt_pass pass_vrp =
6389 gate_vrp, /* gate */
6390 execute_vrp, /* execute */
6393 0, /* static_pass_number */
6394 TV_TREE_VRP, /* tv_id */
6395 PROP_ssa | PROP_alias, /* properties_required */
6396 0, /* properties_provided */
6397 0, /* properties_destroyed */
6398 0, /* todo_flags_start */
6403 | TODO_update_ssa /* todo_flags_finish */