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 *);
50 static tree vrp_evaluate_conditional_warnv_with_ops (enum tree_code,
51 tree, tree, bool, bool *);
53 /* Location information for ASSERT_EXPRs. Each instance of this
54 structure describes an ASSERT_EXPR for an SSA name. Since a single
55 SSA name may have more than one assertion associated with it, these
56 locations are kept in a linked list attached to the corresponding
60 /* Basic block where the assertion would be inserted. */
63 /* Some assertions need to be inserted on an edge (e.g., assertions
64 generated by COND_EXPRs). In those cases, BB will be NULL. */
67 /* Pointer to the statement that generated this assertion. */
68 block_stmt_iterator si;
70 /* Predicate code for the ASSERT_EXPR. Must be COMPARISON_CLASS_P. */
71 enum tree_code comp_code;
73 /* Value being compared against. */
76 /* Expression to compare. */
79 /* Next node in the linked list. */
80 struct assert_locus_d *next;
83 typedef struct assert_locus_d *assert_locus_t;
85 /* If bit I is present, it means that SSA name N_i has a list of
86 assertions that should be inserted in the IL. */
87 static bitmap need_assert_for;
89 /* Array of locations lists where to insert assertions. ASSERTS_FOR[I]
90 holds a list of ASSERT_LOCUS_T nodes that describe where
91 ASSERT_EXPRs for SSA name N_I should be inserted. */
92 static assert_locus_t *asserts_for;
94 /* Set of blocks visited in find_assert_locations. Used to avoid
95 visiting the same block more than once. */
96 static sbitmap blocks_visited;
98 /* Value range array. After propagation, VR_VALUE[I] holds the range
99 of values that SSA name N_I may take. */
100 static value_range_t **vr_value;
102 /* For a PHI node which sets SSA name N_I, VR_COUNTS[I] holds the
103 number of executable edges we saw the last time we visited the
105 static int *vr_phi_edge_counts;
112 static VEC (edge, heap) *to_remove_edges;
113 DEF_VEC_O(switch_update);
114 DEF_VEC_ALLOC_O(switch_update, heap);
115 static VEC (switch_update, heap) *to_update_switch_stmts;
118 /* Return the maximum value for TYPEs base type. */
121 vrp_val_max (const_tree type)
123 if (!INTEGRAL_TYPE_P (type))
126 /* For integer sub-types the values for the base type are relevant. */
127 if (TREE_TYPE (type))
128 type = TREE_TYPE (type);
130 return TYPE_MAX_VALUE (type);
133 /* Return the minimum value for TYPEs base type. */
136 vrp_val_min (const_tree type)
138 if (!INTEGRAL_TYPE_P (type))
141 /* For integer sub-types the values for the base type are relevant. */
142 if (TREE_TYPE (type))
143 type = TREE_TYPE (type);
145 return TYPE_MIN_VALUE (type);
148 /* Return whether VAL is equal to the maximum value of its type. This
149 will be true for a positive overflow infinity. We can't do a
150 simple equality comparison with TYPE_MAX_VALUE because C typedefs
151 and Ada subtypes can produce types whose TYPE_MAX_VALUE is not ==
152 to the integer constant with the same value in the type. */
155 vrp_val_is_max (const_tree val)
157 tree type_max = vrp_val_max (TREE_TYPE (val));
158 return (val == type_max
159 || (type_max != NULL_TREE
160 && operand_equal_p (val, type_max, 0)));
163 /* Return whether VAL is equal to the minimum value of its type. This
164 will be true for a negative overflow infinity. */
167 vrp_val_is_min (const_tree val)
169 tree type_min = vrp_val_min (TREE_TYPE (val));
170 return (val == type_min
171 || (type_min != NULL_TREE
172 && operand_equal_p (val, type_min, 0)));
176 /* Return whether TYPE should use an overflow infinity distinct from
177 TYPE_{MIN,MAX}_VALUE. We use an overflow infinity value to
178 represent a signed overflow during VRP computations. An infinity
179 is distinct from a half-range, which will go from some number to
180 TYPE_{MIN,MAX}_VALUE. */
183 needs_overflow_infinity (const_tree type)
185 return (INTEGRAL_TYPE_P (type)
186 && !TYPE_OVERFLOW_WRAPS (type)
187 /* Integer sub-types never overflow as they are never
188 operands of arithmetic operators. */
189 && !(TREE_TYPE (type) && TREE_TYPE (type) != type));
192 /* Return whether TYPE can support our overflow infinity
193 representation: we use the TREE_OVERFLOW flag, which only exists
194 for constants. If TYPE doesn't support this, we don't optimize
195 cases which would require signed overflow--we drop them to
199 supports_overflow_infinity (const_tree type)
201 tree min = vrp_val_min (type), max = vrp_val_max (type);
202 #ifdef ENABLE_CHECKING
203 gcc_assert (needs_overflow_infinity (type));
205 return (min != NULL_TREE
206 && CONSTANT_CLASS_P (min)
208 && CONSTANT_CLASS_P (max));
211 /* VAL is the maximum or minimum value of a type. Return a
212 corresponding overflow infinity. */
215 make_overflow_infinity (tree val)
217 #ifdef ENABLE_CHECKING
218 gcc_assert (val != NULL_TREE && CONSTANT_CLASS_P (val));
220 val = copy_node (val);
221 TREE_OVERFLOW (val) = 1;
225 /* Return a negative overflow infinity for TYPE. */
228 negative_overflow_infinity (tree type)
230 #ifdef ENABLE_CHECKING
231 gcc_assert (supports_overflow_infinity (type));
233 return make_overflow_infinity (vrp_val_min (type));
236 /* Return a positive overflow infinity for TYPE. */
239 positive_overflow_infinity (tree type)
241 #ifdef ENABLE_CHECKING
242 gcc_assert (supports_overflow_infinity (type));
244 return make_overflow_infinity (vrp_val_max (type));
247 /* Return whether VAL is a negative overflow infinity. */
250 is_negative_overflow_infinity (const_tree val)
252 return (needs_overflow_infinity (TREE_TYPE (val))
253 && CONSTANT_CLASS_P (val)
254 && TREE_OVERFLOW (val)
255 && vrp_val_is_min (val));
258 /* Return whether VAL is a positive overflow infinity. */
261 is_positive_overflow_infinity (const_tree val)
263 return (needs_overflow_infinity (TREE_TYPE (val))
264 && CONSTANT_CLASS_P (val)
265 && TREE_OVERFLOW (val)
266 && vrp_val_is_max (val));
269 /* Return whether VAL is a positive or negative overflow infinity. */
272 is_overflow_infinity (const_tree val)
274 return (needs_overflow_infinity (TREE_TYPE (val))
275 && CONSTANT_CLASS_P (val)
276 && TREE_OVERFLOW (val)
277 && (vrp_val_is_min (val) || vrp_val_is_max (val)));
280 /* If VAL is now an overflow infinity, return VAL. Otherwise, return
281 the same value with TREE_OVERFLOW clear. This can be used to avoid
282 confusing a regular value with an overflow value. */
285 avoid_overflow_infinity (tree val)
287 if (!is_overflow_infinity (val))
290 if (vrp_val_is_max (val))
291 return vrp_val_max (TREE_TYPE (val));
294 #ifdef ENABLE_CHECKING
295 gcc_assert (vrp_val_is_min (val));
297 return vrp_val_min (TREE_TYPE (val));
302 /* Return true if ARG is marked with the nonnull attribute in the
303 current function signature. */
306 nonnull_arg_p (const_tree arg)
308 tree t, attrs, fntype;
309 unsigned HOST_WIDE_INT arg_num;
311 gcc_assert (TREE_CODE (arg) == PARM_DECL && POINTER_TYPE_P (TREE_TYPE (arg)));
313 /* The static chain decl is always non null. */
314 if (arg == cfun->static_chain_decl)
317 fntype = TREE_TYPE (current_function_decl);
318 attrs = lookup_attribute ("nonnull", TYPE_ATTRIBUTES (fntype));
320 /* If "nonnull" wasn't specified, we know nothing about the argument. */
321 if (attrs == NULL_TREE)
324 /* If "nonnull" applies to all the arguments, then ARG is non-null. */
325 if (TREE_VALUE (attrs) == NULL_TREE)
328 /* Get the position number for ARG in the function signature. */
329 for (arg_num = 1, t = DECL_ARGUMENTS (current_function_decl);
331 t = TREE_CHAIN (t), arg_num++)
337 gcc_assert (t == arg);
339 /* Now see if ARG_NUM is mentioned in the nonnull list. */
340 for (t = TREE_VALUE (attrs); t; t = TREE_CHAIN (t))
342 if (compare_tree_int (TREE_VALUE (t), arg_num) == 0)
350 /* Set value range VR to VR_VARYING. */
353 set_value_range_to_varying (value_range_t *vr)
355 vr->type = VR_VARYING;
356 vr->min = vr->max = NULL_TREE;
358 bitmap_clear (vr->equiv);
362 /* Set value range VR to {T, MIN, MAX, EQUIV}. */
365 set_value_range (value_range_t *vr, enum value_range_type t, tree min,
366 tree max, bitmap equiv)
368 #if defined ENABLE_CHECKING
369 /* Check the validity of the range. */
370 if (t == VR_RANGE || t == VR_ANTI_RANGE)
374 gcc_assert (min && max);
376 if (INTEGRAL_TYPE_P (TREE_TYPE (min)) && t == VR_ANTI_RANGE)
377 gcc_assert (!vrp_val_is_min (min) || !vrp_val_is_max (max));
379 cmp = compare_values (min, max);
380 gcc_assert (cmp == 0 || cmp == -1 || cmp == -2);
382 if (needs_overflow_infinity (TREE_TYPE (min)))
383 gcc_assert (!is_overflow_infinity (min)
384 || !is_overflow_infinity (max));
387 if (t == VR_UNDEFINED || t == VR_VARYING)
388 gcc_assert (min == NULL_TREE && max == NULL_TREE);
390 if (t == VR_UNDEFINED || t == VR_VARYING)
391 gcc_assert (equiv == NULL || bitmap_empty_p (equiv));
398 /* Since updating the equivalence set involves deep copying the
399 bitmaps, only do it if absolutely necessary. */
400 if (vr->equiv == NULL
402 vr->equiv = BITMAP_ALLOC (NULL);
404 if (equiv != vr->equiv)
406 if (equiv && !bitmap_empty_p (equiv))
407 bitmap_copy (vr->equiv, equiv);
409 bitmap_clear (vr->equiv);
414 /* Set value range VR to the canonical form of {T, MIN, MAX, EQUIV}.
415 This means adjusting T, MIN and MAX representing the case of a
416 wrapping range with MAX < MIN covering [MIN, type_max] U [type_min, MAX]
417 as anti-rage ~[MAX+1, MIN-1]. Likewise for wrapping anti-ranges.
418 In corner cases where MAX+1 or MIN-1 wraps this will fall back
420 This routine exists to ease canonicalization in the case where we
421 extract ranges from var + CST op limit. */
424 set_and_canonicalize_value_range (value_range_t *vr, enum value_range_type t,
425 tree min, tree max, bitmap equiv)
427 /* Nothing to canonicalize for symbolic or unknown or varying ranges. */
429 && t != VR_ANTI_RANGE)
430 || TREE_CODE (min) != INTEGER_CST
431 || TREE_CODE (max) != INTEGER_CST)
433 set_value_range (vr, t, min, max, equiv);
437 /* Wrong order for min and max, to swap them and the VR type we need
439 if (tree_int_cst_lt (max, min))
441 tree one = build_int_cst (TREE_TYPE (min), 1);
442 tree tmp = int_const_binop (PLUS_EXPR, max, one, 0);
443 max = int_const_binop (MINUS_EXPR, min, one, 0);
446 /* There's one corner case, if we had [C+1, C] before we now have
447 that again. But this represents an empty value range, so drop
448 to varying in this case. */
449 if (tree_int_cst_lt (max, min))
451 set_value_range_to_varying (vr);
455 t = t == VR_RANGE ? VR_ANTI_RANGE : VR_RANGE;
458 /* Anti-ranges that can be represented as ranges should be so. */
459 if (t == VR_ANTI_RANGE)
461 bool is_min = vrp_val_is_min (min);
462 bool is_max = vrp_val_is_max (max);
464 if (is_min && is_max)
466 /* We cannot deal with empty ranges, drop to varying. */
467 set_value_range_to_varying (vr);
471 /* As a special exception preserve non-null ranges. */
472 && !(TYPE_UNSIGNED (TREE_TYPE (min))
473 && integer_zerop (max)))
475 tree one = build_int_cst (TREE_TYPE (max), 1);
476 min = int_const_binop (PLUS_EXPR, max, one, 0);
477 max = vrp_val_max (TREE_TYPE (max));
482 tree one = build_int_cst (TREE_TYPE (min), 1);
483 max = int_const_binop (MINUS_EXPR, min, one, 0);
484 min = vrp_val_min (TREE_TYPE (min));
489 set_value_range (vr, t, min, max, equiv);
492 /* Copy value range FROM into value range TO. */
495 copy_value_range (value_range_t *to, value_range_t *from)
497 set_value_range (to, from->type, from->min, from->max, from->equiv);
500 /* Set value range VR to a single value. This function is only called
501 with values we get from statements, and exists to clear the
502 TREE_OVERFLOW flag so that we don't think we have an overflow
503 infinity when we shouldn't. */
506 set_value_range_to_value (value_range_t *vr, tree val, bitmap equiv)
508 gcc_assert (is_gimple_min_invariant (val));
509 val = avoid_overflow_infinity (val);
510 set_value_range (vr, VR_RANGE, val, val, equiv);
513 /* Set value range VR to a non-negative range of type TYPE.
514 OVERFLOW_INFINITY indicates whether to use an overflow infinity
515 rather than TYPE_MAX_VALUE; this should be true if we determine
516 that the range is nonnegative based on the assumption that signed
517 overflow does not occur. */
520 set_value_range_to_nonnegative (value_range_t *vr, tree type,
521 bool overflow_infinity)
525 if (overflow_infinity && !supports_overflow_infinity (type))
527 set_value_range_to_varying (vr);
531 zero = build_int_cst (type, 0);
532 set_value_range (vr, VR_RANGE, zero,
534 ? positive_overflow_infinity (type)
535 : TYPE_MAX_VALUE (type)),
539 /* Set value range VR to a non-NULL range of type TYPE. */
542 set_value_range_to_nonnull (value_range_t *vr, tree type)
544 tree zero = build_int_cst (type, 0);
545 set_value_range (vr, VR_ANTI_RANGE, zero, zero, vr->equiv);
549 /* Set value range VR to a NULL range of type TYPE. */
552 set_value_range_to_null (value_range_t *vr, tree type)
554 set_value_range_to_value (vr, build_int_cst (type, 0), vr->equiv);
558 /* Set value range VR to a range of a truthvalue of type TYPE. */
561 set_value_range_to_truthvalue (value_range_t *vr, tree type)
563 if (TYPE_PRECISION (type) == 1)
564 set_value_range_to_varying (vr);
566 set_value_range (vr, VR_RANGE,
567 build_int_cst (type, 0), build_int_cst (type, 1),
572 /* Set value range VR to VR_UNDEFINED. */
575 set_value_range_to_undefined (value_range_t *vr)
577 vr->type = VR_UNDEFINED;
578 vr->min = vr->max = NULL_TREE;
580 bitmap_clear (vr->equiv);
584 /* Return value range information for VAR.
586 If we have no values ranges recorded (ie, VRP is not running), then
587 return NULL. Otherwise create an empty range if none existed for VAR. */
589 static value_range_t *
590 get_value_range (const_tree var)
594 unsigned ver = SSA_NAME_VERSION (var);
596 /* If we have no recorded ranges, then return NULL. */
604 /* Create a default value range. */
605 vr_value[ver] = vr = XCNEW (value_range_t);
607 /* Defer allocating the equivalence set. */
610 /* If VAR is a default definition, the variable can take any value
612 sym = SSA_NAME_VAR (var);
613 if (SSA_NAME_IS_DEFAULT_DEF (var))
615 /* Try to use the "nonnull" attribute to create ~[0, 0]
616 anti-ranges for pointers. Note that this is only valid with
617 default definitions of PARM_DECLs. */
618 if (TREE_CODE (sym) == PARM_DECL
619 && POINTER_TYPE_P (TREE_TYPE (sym))
620 && nonnull_arg_p (sym))
621 set_value_range_to_nonnull (vr, TREE_TYPE (sym));
623 set_value_range_to_varying (vr);
629 /* Return true, if VAL1 and VAL2 are equal values for VRP purposes. */
632 vrp_operand_equal_p (const_tree val1, const_tree val2)
636 if (!val1 || !val2 || !operand_equal_p (val1, val2, 0))
638 if (is_overflow_infinity (val1))
639 return is_overflow_infinity (val2);
643 /* Return true, if the bitmaps B1 and B2 are equal. */
646 vrp_bitmap_equal_p (const_bitmap b1, const_bitmap b2)
650 && bitmap_equal_p (b1, b2)));
653 /* Update the value range and equivalence set for variable VAR to
654 NEW_VR. Return true if NEW_VR is different from VAR's previous
657 NOTE: This function assumes that NEW_VR is a temporary value range
658 object created for the sole purpose of updating VAR's range. The
659 storage used by the equivalence set from NEW_VR will be freed by
660 this function. Do not call update_value_range when NEW_VR
661 is the range object associated with another SSA name. */
664 update_value_range (const_tree var, value_range_t *new_vr)
666 value_range_t *old_vr;
669 /* Update the value range, if necessary. */
670 old_vr = get_value_range (var);
671 is_new = old_vr->type != new_vr->type
672 || !vrp_operand_equal_p (old_vr->min, new_vr->min)
673 || !vrp_operand_equal_p (old_vr->max, new_vr->max)
674 || !vrp_bitmap_equal_p (old_vr->equiv, new_vr->equiv);
677 set_value_range (old_vr, new_vr->type, new_vr->min, new_vr->max,
680 BITMAP_FREE (new_vr->equiv);
686 /* Add VAR and VAR's equivalence set to EQUIV. This is the central
687 point where equivalence processing can be turned on/off. */
690 add_equivalence (bitmap *equiv, const_tree var)
692 unsigned ver = SSA_NAME_VERSION (var);
693 value_range_t *vr = vr_value[ver];
696 *equiv = BITMAP_ALLOC (NULL);
697 bitmap_set_bit (*equiv, ver);
699 bitmap_ior_into (*equiv, vr->equiv);
703 /* Return true if VR is ~[0, 0]. */
706 range_is_nonnull (value_range_t *vr)
708 return vr->type == VR_ANTI_RANGE
709 && integer_zerop (vr->min)
710 && integer_zerop (vr->max);
714 /* Return true if VR is [0, 0]. */
717 range_is_null (value_range_t *vr)
719 return vr->type == VR_RANGE
720 && integer_zerop (vr->min)
721 && integer_zerop (vr->max);
725 /* Return true if value range VR involves at least one symbol. */
728 symbolic_range_p (value_range_t *vr)
730 return (!is_gimple_min_invariant (vr->min)
731 || !is_gimple_min_invariant (vr->max));
734 /* Return true if value range VR uses an overflow infinity. */
737 overflow_infinity_range_p (value_range_t *vr)
739 return (vr->type == VR_RANGE
740 && (is_overflow_infinity (vr->min)
741 || is_overflow_infinity (vr->max)));
744 /* Return false if we can not make a valid comparison based on VR;
745 this will be the case if it uses an overflow infinity and overflow
746 is not undefined (i.e., -fno-strict-overflow is in effect).
747 Otherwise return true, and set *STRICT_OVERFLOW_P to true if VR
748 uses an overflow infinity. */
751 usable_range_p (value_range_t *vr, bool *strict_overflow_p)
753 gcc_assert (vr->type == VR_RANGE);
754 if (is_overflow_infinity (vr->min))
756 *strict_overflow_p = true;
757 if (!TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (vr->min)))
760 if (is_overflow_infinity (vr->max))
762 *strict_overflow_p = true;
763 if (!TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (vr->max)))
770 /* Like tree_expr_nonnegative_warnv_p, but this function uses value
771 ranges obtained so far. */
774 vrp_expr_computes_nonnegative (tree expr, bool *strict_overflow_p)
776 return tree_expr_nonnegative_warnv_p (expr, strict_overflow_p);
779 /* Like tree_expr_nonzero_warnv_p, but this function uses value ranges
783 vrp_expr_computes_nonzero (tree expr, bool *strict_overflow_p)
785 if (tree_expr_nonzero_warnv_p (expr, strict_overflow_p))
788 /* If we have an expression of the form &X->a, then the expression
789 is nonnull if X is nonnull. */
790 if (TREE_CODE (expr) == ADDR_EXPR)
792 tree base = get_base_address (TREE_OPERAND (expr, 0));
794 if (base != NULL_TREE
795 && TREE_CODE (base) == INDIRECT_REF
796 && TREE_CODE (TREE_OPERAND (base, 0)) == SSA_NAME)
798 value_range_t *vr = get_value_range (TREE_OPERAND (base, 0));
799 if (range_is_nonnull (vr))
807 /* Returns true if EXPR is a valid value (as expected by compare_values) --
808 a gimple invariant, or SSA_NAME +- CST. */
811 valid_value_p (tree expr)
813 if (TREE_CODE (expr) == SSA_NAME)
816 if (TREE_CODE (expr) == PLUS_EXPR
817 || TREE_CODE (expr) == MINUS_EXPR)
818 return (TREE_CODE (TREE_OPERAND (expr, 0)) == SSA_NAME
819 && TREE_CODE (TREE_OPERAND (expr, 1)) == INTEGER_CST);
821 return is_gimple_min_invariant (expr);
827 -2 if those are incomparable. */
829 operand_less_p (tree val, tree val2)
831 /* LT is folded faster than GE and others. Inline the common case. */
832 if (TREE_CODE (val) == INTEGER_CST && TREE_CODE (val2) == INTEGER_CST)
834 if (TYPE_UNSIGNED (TREE_TYPE (val)))
835 return INT_CST_LT_UNSIGNED (val, val2);
838 if (INT_CST_LT (val, val2))
846 fold_defer_overflow_warnings ();
848 tcmp = fold_binary_to_constant (LT_EXPR, boolean_type_node, val, val2);
850 fold_undefer_and_ignore_overflow_warnings ();
853 || TREE_CODE (tcmp) != INTEGER_CST)
856 if (!integer_zerop (tcmp))
860 /* val >= val2, not considering overflow infinity. */
861 if (is_negative_overflow_infinity (val))
862 return is_negative_overflow_infinity (val2) ? 0 : 1;
863 else if (is_positive_overflow_infinity (val2))
864 return is_positive_overflow_infinity (val) ? 0 : 1;
869 /* Compare two values VAL1 and VAL2. Return
871 -2 if VAL1 and VAL2 cannot be compared at compile-time,
874 +1 if VAL1 > VAL2, and
877 This is similar to tree_int_cst_compare but supports pointer values
878 and values that cannot be compared at compile time.
880 If STRICT_OVERFLOW_P is not NULL, then set *STRICT_OVERFLOW_P to
881 true if the return value is only valid if we assume that signed
882 overflow is undefined. */
885 compare_values_warnv (tree val1, tree val2, bool *strict_overflow_p)
890 /* Below we rely on the fact that VAL1 and VAL2 are both pointers or
892 gcc_assert (POINTER_TYPE_P (TREE_TYPE (val1))
893 == POINTER_TYPE_P (TREE_TYPE (val2)));
894 /* Convert the two values into the same type. This is needed because
895 sizetype causes sign extension even for unsigned types. */
896 val2 = fold_convert (TREE_TYPE (val1), val2);
897 STRIP_USELESS_TYPE_CONVERSION (val2);
899 if ((TREE_CODE (val1) == SSA_NAME
900 || TREE_CODE (val1) == PLUS_EXPR
901 || TREE_CODE (val1) == MINUS_EXPR)
902 && (TREE_CODE (val2) == SSA_NAME
903 || TREE_CODE (val2) == PLUS_EXPR
904 || TREE_CODE (val2) == MINUS_EXPR))
907 enum tree_code code1, code2;
909 /* If VAL1 and VAL2 are of the form 'NAME [+-] CST' or 'NAME',
910 return -1 or +1 accordingly. If VAL1 and VAL2 don't use the
911 same name, return -2. */
912 if (TREE_CODE (val1) == SSA_NAME)
920 code1 = TREE_CODE (val1);
921 n1 = TREE_OPERAND (val1, 0);
922 c1 = TREE_OPERAND (val1, 1);
923 if (tree_int_cst_sgn (c1) == -1)
925 if (is_negative_overflow_infinity (c1))
927 c1 = fold_unary_to_constant (NEGATE_EXPR, TREE_TYPE (c1), c1);
930 code1 = code1 == MINUS_EXPR ? PLUS_EXPR : MINUS_EXPR;
934 if (TREE_CODE (val2) == SSA_NAME)
942 code2 = TREE_CODE (val2);
943 n2 = TREE_OPERAND (val2, 0);
944 c2 = TREE_OPERAND (val2, 1);
945 if (tree_int_cst_sgn (c2) == -1)
947 if (is_negative_overflow_infinity (c2))
949 c2 = fold_unary_to_constant (NEGATE_EXPR, TREE_TYPE (c2), c2);
952 code2 = code2 == MINUS_EXPR ? PLUS_EXPR : MINUS_EXPR;
956 /* Both values must use the same name. */
960 if (code1 == SSA_NAME
961 && code2 == SSA_NAME)
965 /* If overflow is defined we cannot simplify more. */
966 if (!TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (val1)))
969 if (strict_overflow_p != NULL
970 && (code1 == SSA_NAME || !TREE_NO_WARNING (val1))
971 && (code2 == SSA_NAME || !TREE_NO_WARNING (val2)))
972 *strict_overflow_p = true;
974 if (code1 == SSA_NAME)
976 if (code2 == PLUS_EXPR)
977 /* NAME < NAME + CST */
979 else if (code2 == MINUS_EXPR)
980 /* NAME > NAME - CST */
983 else if (code1 == PLUS_EXPR)
985 if (code2 == SSA_NAME)
986 /* NAME + CST > NAME */
988 else if (code2 == PLUS_EXPR)
989 /* NAME + CST1 > NAME + CST2, if CST1 > CST2 */
990 return compare_values_warnv (c1, c2, strict_overflow_p);
991 else if (code2 == MINUS_EXPR)
992 /* NAME + CST1 > NAME - CST2 */
995 else if (code1 == MINUS_EXPR)
997 if (code2 == SSA_NAME)
998 /* NAME - CST < NAME */
1000 else if (code2 == PLUS_EXPR)
1001 /* NAME - CST1 < NAME + CST2 */
1003 else if (code2 == MINUS_EXPR)
1004 /* NAME - CST1 > NAME - CST2, if CST1 < CST2. Notice that
1005 C1 and C2 are swapped in the call to compare_values. */
1006 return compare_values_warnv (c2, c1, strict_overflow_p);
1012 /* We cannot compare non-constants. */
1013 if (!is_gimple_min_invariant (val1) || !is_gimple_min_invariant (val2))
1016 if (!POINTER_TYPE_P (TREE_TYPE (val1)))
1018 /* We cannot compare overflowed values, except for overflow
1020 if (TREE_OVERFLOW (val1) || TREE_OVERFLOW (val2))
1022 if (strict_overflow_p != NULL)
1023 *strict_overflow_p = true;
1024 if (is_negative_overflow_infinity (val1))
1025 return is_negative_overflow_infinity (val2) ? 0 : -1;
1026 else if (is_negative_overflow_infinity (val2))
1028 else if (is_positive_overflow_infinity (val1))
1029 return is_positive_overflow_infinity (val2) ? 0 : 1;
1030 else if (is_positive_overflow_infinity (val2))
1035 return tree_int_cst_compare (val1, val2);
1041 /* First see if VAL1 and VAL2 are not the same. */
1042 if (val1 == val2 || operand_equal_p (val1, val2, 0))
1045 /* If VAL1 is a lower address than VAL2, return -1. */
1046 if (operand_less_p (val1, val2) == 1)
1049 /* If VAL1 is a higher address than VAL2, return +1. */
1050 if (operand_less_p (val2, val1) == 1)
1053 /* If VAL1 is different than VAL2, return +2.
1054 For integer constants we either have already returned -1 or 1
1055 or they are equivalent. We still might succeed in proving
1056 something about non-trivial operands. */
1057 if (TREE_CODE (val1) != INTEGER_CST
1058 || TREE_CODE (val2) != INTEGER_CST)
1060 t = fold_binary_to_constant (NE_EXPR, boolean_type_node, val1, val2);
1061 if (t && integer_onep (t))
1069 /* Compare values like compare_values_warnv, but treat comparisons of
1070 nonconstants which rely on undefined overflow as incomparable. */
1073 compare_values (tree val1, tree val2)
1079 ret = compare_values_warnv (val1, val2, &sop);
1081 && (!is_gimple_min_invariant (val1) || !is_gimple_min_invariant (val2)))
1087 /* Return 1 if VAL is inside value range VR (VR->MIN <= VAL <= VR->MAX),
1088 0 if VAL is not inside VR,
1089 -2 if we cannot tell either way.
1091 FIXME, the current semantics of this functions are a bit quirky
1092 when taken in the context of VRP. In here we do not care
1093 about VR's type. If VR is the anti-range ~[3, 5] the call
1094 value_inside_range (4, VR) will return 1.
1096 This is counter-intuitive in a strict sense, but the callers
1097 currently expect this. They are calling the function
1098 merely to determine whether VR->MIN <= VAL <= VR->MAX. The
1099 callers are applying the VR_RANGE/VR_ANTI_RANGE semantics
1102 This also applies to value_ranges_intersect_p and
1103 range_includes_zero_p. The semantics of VR_RANGE and
1104 VR_ANTI_RANGE should be encoded here, but that also means
1105 adapting the users of these functions to the new semantics.
1107 Benchmark compile/20001226-1.c compilation time after changing this
1111 value_inside_range (tree val, value_range_t * vr)
1115 cmp1 = operand_less_p (val, vr->min);
1121 cmp2 = operand_less_p (vr->max, val);
1129 /* Return true if value ranges VR0 and VR1 have a non-empty
1132 Benchmark compile/20001226-1.c compilation time after changing this
1137 value_ranges_intersect_p (value_range_t *vr0, value_range_t *vr1)
1139 /* The value ranges do not intersect if the maximum of the first range is
1140 less than the minimum of the second range or vice versa.
1141 When those relations are unknown, we can't do any better. */
1142 if (operand_less_p (vr0->max, vr1->min) != 0)
1144 if (operand_less_p (vr1->max, vr0->min) != 0)
1150 /* Return true if VR includes the value zero, false otherwise. FIXME,
1151 currently this will return false for an anti-range like ~[-4, 3].
1152 This will be wrong when the semantics of value_inside_range are
1153 modified (currently the users of this function expect these
1157 range_includes_zero_p (value_range_t *vr)
1161 gcc_assert (vr->type != VR_UNDEFINED
1162 && vr->type != VR_VARYING
1163 && !symbolic_range_p (vr));
1165 zero = build_int_cst (TREE_TYPE (vr->min), 0);
1166 return (value_inside_range (zero, vr) == 1);
1169 /* Return true if T, an SSA_NAME, is known to be nonnegative. Return
1170 false otherwise or if no value range information is available. */
1173 ssa_name_nonnegative_p (const_tree t)
1175 value_range_t *vr = get_value_range (t);
1180 /* Testing for VR_ANTI_RANGE is not useful here as any anti-range
1181 which would return a useful value should be encoded as a VR_RANGE. */
1182 if (vr->type == VR_RANGE)
1184 int result = compare_values (vr->min, integer_zero_node);
1186 return (result == 0 || result == 1);
1191 /* Return true if T, an SSA_NAME, is known to be nonzero. Return
1192 false otherwise or if no value range information is available. */
1195 ssa_name_nonzero_p (const_tree t)
1197 value_range_t *vr = get_value_range (t);
1202 /* A VR_RANGE which does not include zero is a nonzero value. */
1203 if (vr->type == VR_RANGE && !symbolic_range_p (vr))
1204 return ! range_includes_zero_p (vr);
1206 /* A VR_ANTI_RANGE which does include zero is a nonzero value. */
1207 if (vr->type == VR_ANTI_RANGE && !symbolic_range_p (vr))
1208 return range_includes_zero_p (vr);
1214 /* Extract value range information from an ASSERT_EXPR EXPR and store
1218 extract_range_from_assert (value_range_t *vr_p, tree expr)
1220 tree var, cond, limit, min, max, type;
1221 value_range_t *var_vr, *limit_vr;
1222 enum tree_code cond_code;
1224 var = ASSERT_EXPR_VAR (expr);
1225 cond = ASSERT_EXPR_COND (expr);
1227 gcc_assert (COMPARISON_CLASS_P (cond));
1229 /* Find VAR in the ASSERT_EXPR conditional. */
1230 if (var == TREE_OPERAND (cond, 0)
1231 || TREE_CODE (TREE_OPERAND (cond, 0)) == PLUS_EXPR
1232 || TREE_CODE (TREE_OPERAND (cond, 0)) == NOP_EXPR)
1234 /* If the predicate is of the form VAR COMP LIMIT, then we just
1235 take LIMIT from the RHS and use the same comparison code. */
1236 cond_code = TREE_CODE (cond);
1237 limit = TREE_OPERAND (cond, 1);
1238 cond = TREE_OPERAND (cond, 0);
1242 /* If the predicate is of the form LIMIT COMP VAR, then we need
1243 to flip around the comparison code to create the proper range
1245 cond_code = swap_tree_comparison (TREE_CODE (cond));
1246 limit = TREE_OPERAND (cond, 0);
1247 cond = TREE_OPERAND (cond, 1);
1250 limit = avoid_overflow_infinity (limit);
1252 type = TREE_TYPE (limit);
1253 gcc_assert (limit != var);
1255 /* For pointer arithmetic, we only keep track of pointer equality
1257 if (POINTER_TYPE_P (type) && cond_code != NE_EXPR && cond_code != EQ_EXPR)
1259 set_value_range_to_varying (vr_p);
1263 /* If LIMIT is another SSA name and LIMIT has a range of its own,
1264 try to use LIMIT's range to avoid creating symbolic ranges
1266 limit_vr = (TREE_CODE (limit) == SSA_NAME) ? get_value_range (limit) : NULL;
1268 /* LIMIT's range is only interesting if it has any useful information. */
1270 && (limit_vr->type == VR_UNDEFINED
1271 || limit_vr->type == VR_VARYING
1272 || symbolic_range_p (limit_vr)))
1275 /* Initially, the new range has the same set of equivalences of
1276 VAR's range. This will be revised before returning the final
1277 value. Since assertions may be chained via mutually exclusive
1278 predicates, we will need to trim the set of equivalences before
1280 gcc_assert (vr_p->equiv == NULL);
1281 add_equivalence (&vr_p->equiv, var);
1283 /* Extract a new range based on the asserted comparison for VAR and
1284 LIMIT's value range. Notice that if LIMIT has an anti-range, we
1285 will only use it for equality comparisons (EQ_EXPR). For any
1286 other kind of assertion, we cannot derive a range from LIMIT's
1287 anti-range that can be used to describe the new range. For
1288 instance, ASSERT_EXPR <x_2, x_2 <= b_4>. If b_4 is ~[2, 10],
1289 then b_4 takes on the ranges [-INF, 1] and [11, +INF]. There is
1290 no single range for x_2 that could describe LE_EXPR, so we might
1291 as well build the range [b_4, +INF] for it.
1292 One special case we handle is extracting a range from a
1293 range test encoded as (unsigned)var + CST <= limit. */
1294 if (TREE_CODE (cond) == NOP_EXPR
1295 || TREE_CODE (cond) == PLUS_EXPR)
1297 if (TREE_CODE (cond) == PLUS_EXPR)
1299 min = fold_build1 (NEGATE_EXPR, TREE_TYPE (TREE_OPERAND (cond, 1)),
1300 TREE_OPERAND (cond, 1));
1301 max = int_const_binop (PLUS_EXPR, limit, min, 0);
1302 cond = TREE_OPERAND (cond, 0);
1306 min = build_int_cst (TREE_TYPE (var), 0);
1310 /* Make sure to not set TREE_OVERFLOW on the final type
1311 conversion. We are willingly interpreting large positive
1312 unsigned values as negative singed values here. */
1313 min = force_fit_type_double (TREE_TYPE (var), TREE_INT_CST_LOW (min),
1314 TREE_INT_CST_HIGH (min), 0, false);
1315 max = force_fit_type_double (TREE_TYPE (var), TREE_INT_CST_LOW (max),
1316 TREE_INT_CST_HIGH (max), 0, false);
1318 /* We can transform a max, min range to an anti-range or
1319 vice-versa. Use set_and_canonicalize_value_range which does
1321 if (cond_code == LE_EXPR)
1322 set_and_canonicalize_value_range (vr_p, VR_RANGE,
1323 min, max, vr_p->equiv);
1324 else if (cond_code == GT_EXPR)
1325 set_and_canonicalize_value_range (vr_p, VR_ANTI_RANGE,
1326 min, max, vr_p->equiv);
1330 else if (cond_code == EQ_EXPR)
1332 enum value_range_type range_type;
1336 range_type = limit_vr->type;
1337 min = limit_vr->min;
1338 max = limit_vr->max;
1342 range_type = VR_RANGE;
1347 set_value_range (vr_p, range_type, min, max, vr_p->equiv);
1349 /* When asserting the equality VAR == LIMIT and LIMIT is another
1350 SSA name, the new range will also inherit the equivalence set
1352 if (TREE_CODE (limit) == SSA_NAME)
1353 add_equivalence (&vr_p->equiv, limit);
1355 else if (cond_code == NE_EXPR)
1357 /* As described above, when LIMIT's range is an anti-range and
1358 this assertion is an inequality (NE_EXPR), then we cannot
1359 derive anything from the anti-range. For instance, if
1360 LIMIT's range was ~[0, 0], the assertion 'VAR != LIMIT' does
1361 not imply that VAR's range is [0, 0]. So, in the case of
1362 anti-ranges, we just assert the inequality using LIMIT and
1365 If LIMIT_VR is a range, we can only use it to build a new
1366 anti-range if LIMIT_VR is a single-valued range. For
1367 instance, if LIMIT_VR is [0, 1], the predicate
1368 VAR != [0, 1] does not mean that VAR's range is ~[0, 1].
1369 Rather, it means that for value 0 VAR should be ~[0, 0]
1370 and for value 1, VAR should be ~[1, 1]. We cannot
1371 represent these ranges.
1373 The only situation in which we can build a valid
1374 anti-range is when LIMIT_VR is a single-valued range
1375 (i.e., LIMIT_VR->MIN == LIMIT_VR->MAX). In that case,
1376 build the anti-range ~[LIMIT_VR->MIN, LIMIT_VR->MAX]. */
1378 && limit_vr->type == VR_RANGE
1379 && compare_values (limit_vr->min, limit_vr->max) == 0)
1381 min = limit_vr->min;
1382 max = limit_vr->max;
1386 /* In any other case, we cannot use LIMIT's range to build a
1387 valid anti-range. */
1391 /* If MIN and MAX cover the whole range for their type, then
1392 just use the original LIMIT. */
1393 if (INTEGRAL_TYPE_P (type)
1394 && vrp_val_is_min (min)
1395 && vrp_val_is_max (max))
1398 set_value_range (vr_p, VR_ANTI_RANGE, min, max, vr_p->equiv);
1400 else if (cond_code == LE_EXPR || cond_code == LT_EXPR)
1402 min = TYPE_MIN_VALUE (type);
1404 if (limit_vr == NULL || limit_vr->type == VR_ANTI_RANGE)
1408 /* If LIMIT_VR is of the form [N1, N2], we need to build the
1409 range [MIN, N2] for LE_EXPR and [MIN, N2 - 1] for
1411 max = limit_vr->max;
1414 /* If the maximum value forces us to be out of bounds, simply punt.
1415 It would be pointless to try and do anything more since this
1416 all should be optimized away above us. */
1417 if ((cond_code == LT_EXPR
1418 && compare_values (max, min) == 0)
1419 || is_overflow_infinity (max))
1420 set_value_range_to_varying (vr_p);
1423 /* For LT_EXPR, we create the range [MIN, MAX - 1]. */
1424 if (cond_code == LT_EXPR)
1426 tree one = build_int_cst (type, 1);
1427 max = fold_build2 (MINUS_EXPR, type, max, one);
1429 TREE_NO_WARNING (max) = 1;
1432 set_value_range (vr_p, VR_RANGE, min, max, vr_p->equiv);
1435 else if (cond_code == GE_EXPR || cond_code == GT_EXPR)
1437 max = TYPE_MAX_VALUE (type);
1439 if (limit_vr == NULL || limit_vr->type == VR_ANTI_RANGE)
1443 /* If LIMIT_VR is of the form [N1, N2], we need to build the
1444 range [N1, MAX] for GE_EXPR and [N1 + 1, MAX] for
1446 min = limit_vr->min;
1449 /* If the minimum value forces us to be out of bounds, simply punt.
1450 It would be pointless to try and do anything more since this
1451 all should be optimized away above us. */
1452 if ((cond_code == GT_EXPR
1453 && compare_values (min, max) == 0)
1454 || is_overflow_infinity (min))
1455 set_value_range_to_varying (vr_p);
1458 /* For GT_EXPR, we create the range [MIN + 1, MAX]. */
1459 if (cond_code == GT_EXPR)
1461 tree one = build_int_cst (type, 1);
1462 min = fold_build2 (PLUS_EXPR, type, min, one);
1464 TREE_NO_WARNING (min) = 1;
1467 set_value_range (vr_p, VR_RANGE, min, max, vr_p->equiv);
1473 /* If VAR already had a known range, it may happen that the new
1474 range we have computed and VAR's range are not compatible. For
1478 p_6 = ASSERT_EXPR <p_5, p_5 == NULL>;
1480 p_8 = ASSERT_EXPR <p_6, p_6 != NULL>;
1482 While the above comes from a faulty program, it will cause an ICE
1483 later because p_8 and p_6 will have incompatible ranges and at
1484 the same time will be considered equivalent. A similar situation
1488 i_6 = ASSERT_EXPR <i_5, i_5 > 10>;
1490 i_7 = ASSERT_EXPR <i_6, i_6 < 5>;
1492 Again i_6 and i_7 will have incompatible ranges. It would be
1493 pointless to try and do anything with i_7's range because
1494 anything dominated by 'if (i_5 < 5)' will be optimized away.
1495 Note, due to the wa in which simulation proceeds, the statement
1496 i_7 = ASSERT_EXPR <...> we would never be visited because the
1497 conditional 'if (i_5 < 5)' always evaluates to false. However,
1498 this extra check does not hurt and may protect against future
1499 changes to VRP that may get into a situation similar to the
1500 NULL pointer dereference example.
1502 Note that these compatibility tests are only needed when dealing
1503 with ranges or a mix of range and anti-range. If VAR_VR and VR_P
1504 are both anti-ranges, they will always be compatible, because two
1505 anti-ranges will always have a non-empty intersection. */
1507 var_vr = get_value_range (var);
1509 /* We may need to make adjustments when VR_P and VAR_VR are numeric
1510 ranges or anti-ranges. */
1511 if (vr_p->type == VR_VARYING
1512 || vr_p->type == VR_UNDEFINED
1513 || var_vr->type == VR_VARYING
1514 || var_vr->type == VR_UNDEFINED
1515 || symbolic_range_p (vr_p)
1516 || symbolic_range_p (var_vr))
1519 if (var_vr->type == VR_RANGE && vr_p->type == VR_RANGE)
1521 /* If the two ranges have a non-empty intersection, we can
1522 refine the resulting range. Since the assert expression
1523 creates an equivalency and at the same time it asserts a
1524 predicate, we can take the intersection of the two ranges to
1525 get better precision. */
1526 if (value_ranges_intersect_p (var_vr, vr_p))
1528 /* Use the larger of the two minimums. */
1529 if (compare_values (vr_p->min, var_vr->min) == -1)
1534 /* Use the smaller of the two maximums. */
1535 if (compare_values (vr_p->max, var_vr->max) == 1)
1540 set_value_range (vr_p, vr_p->type, min, max, vr_p->equiv);
1544 /* The two ranges do not intersect, set the new range to
1545 VARYING, because we will not be able to do anything
1546 meaningful with it. */
1547 set_value_range_to_varying (vr_p);
1550 else if ((var_vr->type == VR_RANGE && vr_p->type == VR_ANTI_RANGE)
1551 || (var_vr->type == VR_ANTI_RANGE && vr_p->type == VR_RANGE))
1553 /* A range and an anti-range will cancel each other only if
1554 their ends are the same. For instance, in the example above,
1555 p_8's range ~[0, 0] and p_6's range [0, 0] are incompatible,
1556 so VR_P should be set to VR_VARYING. */
1557 if (compare_values (var_vr->min, vr_p->min) == 0
1558 && compare_values (var_vr->max, vr_p->max) == 0)
1559 set_value_range_to_varying (vr_p);
1562 tree min, max, anti_min, anti_max, real_min, real_max;
1565 /* We want to compute the logical AND of the two ranges;
1566 there are three cases to consider.
1569 1. The VR_ANTI_RANGE range is completely within the
1570 VR_RANGE and the endpoints of the ranges are
1571 different. In that case the resulting range
1572 should be whichever range is more precise.
1573 Typically that will be the VR_RANGE.
1575 2. The VR_ANTI_RANGE is completely disjoint from
1576 the VR_RANGE. In this case the resulting range
1577 should be the VR_RANGE.
1579 3. There is some overlap between the VR_ANTI_RANGE
1582 3a. If the high limit of the VR_ANTI_RANGE resides
1583 within the VR_RANGE, then the result is a new
1584 VR_RANGE starting at the high limit of the
1585 the VR_ANTI_RANGE + 1 and extending to the
1586 high limit of the original VR_RANGE.
1588 3b. If the low limit of the VR_ANTI_RANGE resides
1589 within the VR_RANGE, then the result is a new
1590 VR_RANGE starting at the low limit of the original
1591 VR_RANGE and extending to the low limit of the
1592 VR_ANTI_RANGE - 1. */
1593 if (vr_p->type == VR_ANTI_RANGE)
1595 anti_min = vr_p->min;
1596 anti_max = vr_p->max;
1597 real_min = var_vr->min;
1598 real_max = var_vr->max;
1602 anti_min = var_vr->min;
1603 anti_max = var_vr->max;
1604 real_min = vr_p->min;
1605 real_max = vr_p->max;
1609 /* Case 1, VR_ANTI_RANGE completely within VR_RANGE,
1610 not including any endpoints. */
1611 if (compare_values (anti_max, real_max) == -1
1612 && compare_values (anti_min, real_min) == 1)
1614 /* If the range is covering the whole valid range of
1615 the type keep the anti-range. */
1616 if (!vrp_val_is_min (real_min)
1617 || !vrp_val_is_max (real_max))
1618 set_value_range (vr_p, VR_RANGE, real_min,
1619 real_max, vr_p->equiv);
1621 /* Case 2, VR_ANTI_RANGE completely disjoint from
1623 else if (compare_values (anti_min, real_max) == 1
1624 || compare_values (anti_max, real_min) == -1)
1626 set_value_range (vr_p, VR_RANGE, real_min,
1627 real_max, vr_p->equiv);
1629 /* Case 3a, the anti-range extends into the low
1630 part of the real range. Thus creating a new
1631 low for the real range. */
1632 else if (((cmp = compare_values (anti_max, real_min)) == 1
1634 && compare_values (anti_max, real_max) == -1)
1636 gcc_assert (!is_positive_overflow_infinity (anti_max));
1637 if (needs_overflow_infinity (TREE_TYPE (anti_max))
1638 && vrp_val_is_max (anti_max))
1640 if (!supports_overflow_infinity (TREE_TYPE (var_vr->min)))
1642 set_value_range_to_varying (vr_p);
1645 min = positive_overflow_infinity (TREE_TYPE (var_vr->min));
1647 else if (!POINTER_TYPE_P (TREE_TYPE (var_vr->min)))
1648 min = fold_build2 (PLUS_EXPR, TREE_TYPE (var_vr->min),
1650 build_int_cst (TREE_TYPE (var_vr->min), 1));
1652 min = fold_build2 (POINTER_PLUS_EXPR, TREE_TYPE (var_vr->min),
1653 anti_max, size_int (1));
1655 set_value_range (vr_p, VR_RANGE, min, max, vr_p->equiv);
1657 /* Case 3b, the anti-range extends into the high
1658 part of the real range. Thus creating a new
1659 higher for the real range. */
1660 else if (compare_values (anti_min, real_min) == 1
1661 && ((cmp = compare_values (anti_min, real_max)) == -1
1664 gcc_assert (!is_negative_overflow_infinity (anti_min));
1665 if (needs_overflow_infinity (TREE_TYPE (anti_min))
1666 && vrp_val_is_min (anti_min))
1668 if (!supports_overflow_infinity (TREE_TYPE (var_vr->min)))
1670 set_value_range_to_varying (vr_p);
1673 max = negative_overflow_infinity (TREE_TYPE (var_vr->min));
1675 else if (!POINTER_TYPE_P (TREE_TYPE (var_vr->min)))
1676 max = fold_build2 (MINUS_EXPR, TREE_TYPE (var_vr->min),
1678 build_int_cst (TREE_TYPE (var_vr->min), 1));
1680 max = fold_build2 (POINTER_PLUS_EXPR, TREE_TYPE (var_vr->min),
1684 set_value_range (vr_p, VR_RANGE, min, max, vr_p->equiv);
1691 /* Extract range information from SSA name VAR and store it in VR. If
1692 VAR has an interesting range, use it. Otherwise, create the
1693 range [VAR, VAR] and return it. This is useful in situations where
1694 we may have conditionals testing values of VARYING names. For
1701 Even if y_5 is deemed VARYING, we can determine that x_3 > y_5 is
1705 extract_range_from_ssa_name (value_range_t *vr, tree var)
1707 value_range_t *var_vr = get_value_range (var);
1709 if (var_vr->type != VR_UNDEFINED && var_vr->type != VR_VARYING)
1710 copy_value_range (vr, var_vr);
1712 set_value_range (vr, VR_RANGE, var, var, NULL);
1714 add_equivalence (&vr->equiv, var);
1718 /* Wrapper around int_const_binop. If the operation overflows and we
1719 are not using wrapping arithmetic, then adjust the result to be
1720 -INF or +INF depending on CODE, VAL1 and VAL2. This can return
1721 NULL_TREE if we need to use an overflow infinity representation but
1722 the type does not support it. */
1725 vrp_int_const_binop (enum tree_code code, tree val1, tree val2)
1729 res = int_const_binop (code, val1, val2, 0);
1731 /* If we are not using wrapping arithmetic, operate symbolically
1732 on -INF and +INF. */
1733 if (TYPE_OVERFLOW_WRAPS (TREE_TYPE (val1)))
1735 int checkz = compare_values (res, val1);
1736 bool overflow = false;
1738 /* Ensure that res = val1 [+*] val2 >= val1
1739 or that res = val1 - val2 <= val1. */
1740 if ((code == PLUS_EXPR
1741 && !(checkz == 1 || checkz == 0))
1742 || (code == MINUS_EXPR
1743 && !(checkz == 0 || checkz == -1)))
1747 /* Checking for multiplication overflow is done by dividing the
1748 output of the multiplication by the first input of the
1749 multiplication. If the result of that division operation is
1750 not equal to the second input of the multiplication, then the
1751 multiplication overflowed. */
1752 else if (code == MULT_EXPR && !integer_zerop (val1))
1754 tree tmp = int_const_binop (TRUNC_DIV_EXPR,
1757 int check = compare_values (tmp, val2);
1765 res = copy_node (res);
1766 TREE_OVERFLOW (res) = 1;
1770 else if ((TREE_OVERFLOW (res)
1771 && !TREE_OVERFLOW (val1)
1772 && !TREE_OVERFLOW (val2))
1773 || is_overflow_infinity (val1)
1774 || is_overflow_infinity (val2))
1776 /* If the operation overflowed but neither VAL1 nor VAL2 are
1777 overflown, return -INF or +INF depending on the operation
1778 and the combination of signs of the operands. */
1779 int sgn1 = tree_int_cst_sgn (val1);
1780 int sgn2 = tree_int_cst_sgn (val2);
1782 if (needs_overflow_infinity (TREE_TYPE (res))
1783 && !supports_overflow_infinity (TREE_TYPE (res)))
1786 /* We have to punt on adding infinities of different signs,
1787 since we can't tell what the sign of the result should be.
1788 Likewise for subtracting infinities of the same sign. */
1789 if (((code == PLUS_EXPR && sgn1 != sgn2)
1790 || (code == MINUS_EXPR && sgn1 == sgn2))
1791 && is_overflow_infinity (val1)
1792 && is_overflow_infinity (val2))
1795 /* Don't try to handle division or shifting of infinities. */
1796 if ((code == TRUNC_DIV_EXPR
1797 || code == FLOOR_DIV_EXPR
1798 || code == CEIL_DIV_EXPR
1799 || code == EXACT_DIV_EXPR
1800 || code == ROUND_DIV_EXPR
1801 || code == RSHIFT_EXPR)
1802 && (is_overflow_infinity (val1)
1803 || is_overflow_infinity (val2)))
1806 /* Notice that we only need to handle the restricted set of
1807 operations handled by extract_range_from_binary_expr.
1808 Among them, only multiplication, addition and subtraction
1809 can yield overflow without overflown operands because we
1810 are working with integral types only... except in the
1811 case VAL1 = -INF and VAL2 = -1 which overflows to +INF
1812 for division too. */
1814 /* For multiplication, the sign of the overflow is given
1815 by the comparison of the signs of the operands. */
1816 if ((code == MULT_EXPR && sgn1 == sgn2)
1817 /* For addition, the operands must be of the same sign
1818 to yield an overflow. Its sign is therefore that
1819 of one of the operands, for example the first. For
1820 infinite operands X + -INF is negative, not positive. */
1821 || (code == PLUS_EXPR
1823 ? !is_negative_overflow_infinity (val2)
1824 : is_positive_overflow_infinity (val2)))
1825 /* For subtraction, non-infinite operands must be of
1826 different signs to yield an overflow. Its sign is
1827 therefore that of the first operand or the opposite of
1828 that of the second operand. A first operand of 0 counts
1829 as positive here, for the corner case 0 - (-INF), which
1830 overflows, but must yield +INF. For infinite operands 0
1831 - INF is negative, not positive. */
1832 || (code == MINUS_EXPR
1834 ? !is_positive_overflow_infinity (val2)
1835 : is_negative_overflow_infinity (val2)))
1836 /* We only get in here with positive shift count, so the
1837 overflow direction is the same as the sign of val1.
1838 Actually rshift does not overflow at all, but we only
1839 handle the case of shifting overflowed -INF and +INF. */
1840 || (code == RSHIFT_EXPR
1842 /* For division, the only case is -INF / -1 = +INF. */
1843 || code == TRUNC_DIV_EXPR
1844 || code == FLOOR_DIV_EXPR
1845 || code == CEIL_DIV_EXPR
1846 || code == EXACT_DIV_EXPR
1847 || code == ROUND_DIV_EXPR)
1848 return (needs_overflow_infinity (TREE_TYPE (res))
1849 ? positive_overflow_infinity (TREE_TYPE (res))
1850 : TYPE_MAX_VALUE (TREE_TYPE (res)));
1852 return (needs_overflow_infinity (TREE_TYPE (res))
1853 ? negative_overflow_infinity (TREE_TYPE (res))
1854 : TYPE_MIN_VALUE (TREE_TYPE (res)));
1861 /* Extract range information from a binary expression EXPR based on
1862 the ranges of each of its operands and the expression code. */
1865 extract_range_from_binary_expr (value_range_t *vr,
1866 enum tree_code code,
1867 tree expr_type, tree op0, tree op1)
1869 enum value_range_type type;
1872 value_range_t vr0 = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
1873 value_range_t vr1 = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
1875 /* Not all binary expressions can be applied to ranges in a
1876 meaningful way. Handle only arithmetic operations. */
1877 if (code != PLUS_EXPR
1878 && code != MINUS_EXPR
1879 && code != POINTER_PLUS_EXPR
1880 && code != MULT_EXPR
1881 && code != TRUNC_DIV_EXPR
1882 && code != FLOOR_DIV_EXPR
1883 && code != CEIL_DIV_EXPR
1884 && code != EXACT_DIV_EXPR
1885 && code != ROUND_DIV_EXPR
1886 && code != RSHIFT_EXPR
1889 && code != BIT_AND_EXPR
1890 && code != TRUTH_AND_EXPR
1891 && code != TRUTH_OR_EXPR)
1893 set_value_range_to_varying (vr);
1897 /* Get value ranges for each operand. For constant operands, create
1898 a new value range with the operand to simplify processing. */
1899 if (TREE_CODE (op0) == SSA_NAME)
1900 vr0 = *(get_value_range (op0));
1901 else if (is_gimple_min_invariant (op0))
1902 set_value_range_to_value (&vr0, op0, NULL);
1904 set_value_range_to_varying (&vr0);
1906 if (TREE_CODE (op1) == SSA_NAME)
1907 vr1 = *(get_value_range (op1));
1908 else if (is_gimple_min_invariant (op1))
1909 set_value_range_to_value (&vr1, op1, NULL);
1911 set_value_range_to_varying (&vr1);
1913 /* If either range is UNDEFINED, so is the result. */
1914 if (vr0.type == VR_UNDEFINED || vr1.type == VR_UNDEFINED)
1916 set_value_range_to_undefined (vr);
1920 /* The type of the resulting value range defaults to VR0.TYPE. */
1923 /* Refuse to operate on VARYING ranges, ranges of different kinds
1924 and symbolic ranges. As an exception, we allow BIT_AND_EXPR
1925 because we may be able to derive a useful range even if one of
1926 the operands is VR_VARYING or symbolic range. TODO, we may be
1927 able to derive anti-ranges in some cases. */
1928 if (code != BIT_AND_EXPR
1929 && code != TRUTH_AND_EXPR
1930 && code != TRUTH_OR_EXPR
1931 && (vr0.type == VR_VARYING
1932 || vr1.type == VR_VARYING
1933 || vr0.type != vr1.type
1934 || symbolic_range_p (&vr0)
1935 || symbolic_range_p (&vr1)))
1937 set_value_range_to_varying (vr);
1941 /* Now evaluate the expression to determine the new range. */
1942 if (POINTER_TYPE_P (expr_type)
1943 || POINTER_TYPE_P (TREE_TYPE (op0))
1944 || POINTER_TYPE_P (TREE_TYPE (op1)))
1946 if (code == MIN_EXPR || code == MAX_EXPR)
1948 /* For MIN/MAX expressions with pointers, we only care about
1949 nullness, if both are non null, then the result is nonnull.
1950 If both are null, then the result is null. Otherwise they
1952 if (range_is_nonnull (&vr0) && range_is_nonnull (&vr1))
1953 set_value_range_to_nonnull (vr, expr_type);
1954 else if (range_is_null (&vr0) && range_is_null (&vr1))
1955 set_value_range_to_null (vr, expr_type);
1957 set_value_range_to_varying (vr);
1961 gcc_assert (code == POINTER_PLUS_EXPR);
1962 /* For pointer types, we are really only interested in asserting
1963 whether the expression evaluates to non-NULL. */
1964 if (range_is_nonnull (&vr0) || range_is_nonnull (&vr1))
1965 set_value_range_to_nonnull (vr, expr_type);
1966 else if (range_is_null (&vr0) && range_is_null (&vr1))
1967 set_value_range_to_null (vr, expr_type);
1969 set_value_range_to_varying (vr);
1974 /* For integer ranges, apply the operation to each end of the
1975 range and see what we end up with. */
1976 if (code == TRUTH_AND_EXPR
1977 || code == TRUTH_OR_EXPR)
1979 /* If one of the operands is zero, we know that the whole
1980 expression evaluates zero. */
1981 if (code == TRUTH_AND_EXPR
1982 && ((vr0.type == VR_RANGE
1983 && integer_zerop (vr0.min)
1984 && integer_zerop (vr0.max))
1985 || (vr1.type == VR_RANGE
1986 && integer_zerop (vr1.min)
1987 && integer_zerop (vr1.max))))
1990 min = max = build_int_cst (expr_type, 0);
1992 /* If one of the operands is one, we know that the whole
1993 expression evaluates one. */
1994 else if (code == TRUTH_OR_EXPR
1995 && ((vr0.type == VR_RANGE
1996 && integer_onep (vr0.min)
1997 && integer_onep (vr0.max))
1998 || (vr1.type == VR_RANGE
1999 && integer_onep (vr1.min)
2000 && integer_onep (vr1.max))))
2003 min = max = build_int_cst (expr_type, 1);
2005 else if (vr0.type != VR_VARYING
2006 && vr1.type != VR_VARYING
2007 && vr0.type == vr1.type
2008 && !symbolic_range_p (&vr0)
2009 && !overflow_infinity_range_p (&vr0)
2010 && !symbolic_range_p (&vr1)
2011 && !overflow_infinity_range_p (&vr1))
2013 /* Boolean expressions cannot be folded with int_const_binop. */
2014 min = fold_binary (code, expr_type, vr0.min, vr1.min);
2015 max = fold_binary (code, expr_type, vr0.max, vr1.max);
2019 /* The result of a TRUTH_*_EXPR is always true or false. */
2020 set_value_range_to_truthvalue (vr, expr_type);
2024 else if (code == PLUS_EXPR
2026 || code == MAX_EXPR)
2028 /* If we have a PLUS_EXPR with two VR_ANTI_RANGEs, drop to
2029 VR_VARYING. It would take more effort to compute a precise
2030 range for such a case. For example, if we have op0 == 1 and
2031 op1 == -1 with their ranges both being ~[0,0], we would have
2032 op0 + op1 == 0, so we cannot claim that the sum is in ~[0,0].
2033 Note that we are guaranteed to have vr0.type == vr1.type at
2035 if (code == PLUS_EXPR && vr0.type == VR_ANTI_RANGE)
2037 set_value_range_to_varying (vr);
2041 /* For operations that make the resulting range directly
2042 proportional to the original ranges, apply the operation to
2043 the same end of each range. */
2044 min = vrp_int_const_binop (code, vr0.min, vr1.min);
2045 max = vrp_int_const_binop (code, vr0.max, vr1.max);
2047 else if (code == MULT_EXPR
2048 || code == TRUNC_DIV_EXPR
2049 || code == FLOOR_DIV_EXPR
2050 || code == CEIL_DIV_EXPR
2051 || code == EXACT_DIV_EXPR
2052 || code == ROUND_DIV_EXPR
2053 || code == RSHIFT_EXPR)
2059 /* If we have an unsigned MULT_EXPR with two VR_ANTI_RANGEs,
2060 drop to VR_VARYING. It would take more effort to compute a
2061 precise range for such a case. For example, if we have
2062 op0 == 65536 and op1 == 65536 with their ranges both being
2063 ~[0,0] on a 32-bit machine, we would have op0 * op1 == 0, so
2064 we cannot claim that the product is in ~[0,0]. Note that we
2065 are guaranteed to have vr0.type == vr1.type at this
2067 if (code == MULT_EXPR
2068 && vr0.type == VR_ANTI_RANGE
2069 && !TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (op0)))
2071 set_value_range_to_varying (vr);
2075 /* If we have a RSHIFT_EXPR with any shift values outside [0..prec-1],
2076 then drop to VR_VARYING. Outside of this range we get undefined
2077 behavior from the shift operation. We cannot even trust
2078 SHIFT_COUNT_TRUNCATED at this stage, because that applies to rtl
2079 shifts, and the operation at the tree level may be widened. */
2080 if (code == RSHIFT_EXPR)
2082 if (vr1.type == VR_ANTI_RANGE
2083 || !vrp_expr_computes_nonnegative (op1, &sop)
2085 (build_int_cst (TREE_TYPE (vr1.max),
2086 TYPE_PRECISION (expr_type) - 1),
2089 set_value_range_to_varying (vr);
2094 /* Multiplications and divisions are a bit tricky to handle,
2095 depending on the mix of signs we have in the two ranges, we
2096 need to operate on different values to get the minimum and
2097 maximum values for the new range. One approach is to figure
2098 out all the variations of range combinations and do the
2101 However, this involves several calls to compare_values and it
2102 is pretty convoluted. It's simpler to do the 4 operations
2103 (MIN0 OP MIN1, MIN0 OP MAX1, MAX0 OP MIN1 and MAX0 OP MAX0 OP
2104 MAX1) and then figure the smallest and largest values to form
2107 /* Divisions by zero result in a VARYING value. */
2108 else if (code != MULT_EXPR
2109 && (vr0.type == VR_ANTI_RANGE || range_includes_zero_p (&vr1)))
2111 set_value_range_to_varying (vr);
2115 /* Compute the 4 cross operations. */
2117 val[0] = vrp_int_const_binop (code, vr0.min, vr1.min);
2118 if (val[0] == NULL_TREE)
2121 if (vr1.max == vr1.min)
2125 val[1] = vrp_int_const_binop (code, vr0.min, vr1.max);
2126 if (val[1] == NULL_TREE)
2130 if (vr0.max == vr0.min)
2134 val[2] = vrp_int_const_binop (code, vr0.max, vr1.min);
2135 if (val[2] == NULL_TREE)
2139 if (vr0.min == vr0.max || vr1.min == vr1.max)
2143 val[3] = vrp_int_const_binop (code, vr0.max, vr1.max);
2144 if (val[3] == NULL_TREE)
2150 set_value_range_to_varying (vr);
2154 /* Set MIN to the minimum of VAL[i] and MAX to the maximum
2158 for (i = 1; i < 4; i++)
2160 if (!is_gimple_min_invariant (min)
2161 || (TREE_OVERFLOW (min) && !is_overflow_infinity (min))
2162 || !is_gimple_min_invariant (max)
2163 || (TREE_OVERFLOW (max) && !is_overflow_infinity (max)))
2168 if (!is_gimple_min_invariant (val[i])
2169 || (TREE_OVERFLOW (val[i])
2170 && !is_overflow_infinity (val[i])))
2172 /* If we found an overflowed value, set MIN and MAX
2173 to it so that we set the resulting range to
2179 if (compare_values (val[i], min) == -1)
2182 if (compare_values (val[i], max) == 1)
2187 else if (code == MINUS_EXPR)
2189 /* If we have a MINUS_EXPR with two VR_ANTI_RANGEs, drop to
2190 VR_VARYING. It would take more effort to compute a precise
2191 range for such a case. For example, if we have op0 == 1 and
2192 op1 == 1 with their ranges both being ~[0,0], we would have
2193 op0 - op1 == 0, so we cannot claim that the difference is in
2194 ~[0,0]. Note that we are guaranteed to have
2195 vr0.type == vr1.type at this point. */
2196 if (vr0.type == VR_ANTI_RANGE)
2198 set_value_range_to_varying (vr);
2202 /* For MINUS_EXPR, apply the operation to the opposite ends of
2204 min = vrp_int_const_binop (code, vr0.min, vr1.max);
2205 max = vrp_int_const_binop (code, vr0.max, vr1.min);
2207 else if (code == BIT_AND_EXPR)
2209 if (vr0.type == VR_RANGE
2210 && vr0.min == vr0.max
2211 && TREE_CODE (vr0.max) == INTEGER_CST
2212 && !TREE_OVERFLOW (vr0.max)
2213 && tree_int_cst_sgn (vr0.max) >= 0)
2215 min = build_int_cst (expr_type, 0);
2218 else if (vr1.type == VR_RANGE
2219 && vr1.min == vr1.max
2220 && TREE_CODE (vr1.max) == INTEGER_CST
2221 && !TREE_OVERFLOW (vr1.max)
2222 && tree_int_cst_sgn (vr1.max) >= 0)
2225 min = build_int_cst (expr_type, 0);
2230 set_value_range_to_varying (vr);
2237 /* If either MIN or MAX overflowed, then set the resulting range to
2238 VARYING. But we do accept an overflow infinity
2240 if (min == NULL_TREE
2241 || !is_gimple_min_invariant (min)
2242 || (TREE_OVERFLOW (min) && !is_overflow_infinity (min))
2244 || !is_gimple_min_invariant (max)
2245 || (TREE_OVERFLOW (max) && !is_overflow_infinity (max)))
2247 set_value_range_to_varying (vr);
2253 2) [-INF, +-INF(OVF)]
2254 3) [+-INF(OVF), +INF]
2255 4) [+-INF(OVF), +-INF(OVF)]
2256 We learn nothing when we have INF and INF(OVF) on both sides.
2257 Note that we do accept [-INF, -INF] and [+INF, +INF] without
2259 if ((vrp_val_is_min (min) || is_overflow_infinity (min))
2260 && (vrp_val_is_max (max) || is_overflow_infinity (max)))
2262 set_value_range_to_varying (vr);
2266 cmp = compare_values (min, max);
2267 if (cmp == -2 || cmp == 1)
2269 /* If the new range has its limits swapped around (MIN > MAX),
2270 then the operation caused one of them to wrap around, mark
2271 the new range VARYING. */
2272 set_value_range_to_varying (vr);
2275 set_value_range (vr, type, min, max, NULL);
2279 /* Extract range information from a unary expression EXPR based on
2280 the range of its operand and the expression code. */
2283 extract_range_from_unary_expr (value_range_t *vr, enum tree_code code,
2284 tree type, tree op0)
2288 value_range_t vr0 = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
2290 /* Refuse to operate on certain unary expressions for which we
2291 cannot easily determine a resulting range. */
2292 if (code == FIX_TRUNC_EXPR
2293 || code == FLOAT_EXPR
2294 || code == BIT_NOT_EXPR
2295 || code == CONJ_EXPR)
2297 set_value_range_to_varying (vr);
2301 /* Get value ranges for the operand. For constant operands, create
2302 a new value range with the operand to simplify processing. */
2303 if (TREE_CODE (op0) == SSA_NAME)
2304 vr0 = *(get_value_range (op0));
2305 else if (is_gimple_min_invariant (op0))
2306 set_value_range_to_value (&vr0, op0, NULL);
2308 set_value_range_to_varying (&vr0);
2310 /* If VR0 is UNDEFINED, so is the result. */
2311 if (vr0.type == VR_UNDEFINED)
2313 set_value_range_to_undefined (vr);
2317 /* Refuse to operate on symbolic ranges, or if neither operand is
2318 a pointer or integral type. */
2319 if ((!INTEGRAL_TYPE_P (TREE_TYPE (op0))
2320 && !POINTER_TYPE_P (TREE_TYPE (op0)))
2321 || (vr0.type != VR_VARYING
2322 && symbolic_range_p (&vr0)))
2324 set_value_range_to_varying (vr);
2328 /* If the expression involves pointers, we are only interested in
2329 determining if it evaluates to NULL [0, 0] or non-NULL (~[0, 0]). */
2330 if (POINTER_TYPE_P (type) || POINTER_TYPE_P (TREE_TYPE (op0)))
2335 if (range_is_nonnull (&vr0)
2336 || (tree_unary_nonzero_warnv_p (code, type, op0, &sop)
2338 set_value_range_to_nonnull (vr, type);
2339 else if (range_is_null (&vr0))
2340 set_value_range_to_null (vr, type);
2342 set_value_range_to_varying (vr);
2347 /* Handle unary expressions on integer ranges. */
2348 if ((code == NOP_EXPR
2349 || code == CONVERT_EXPR)
2350 && INTEGRAL_TYPE_P (type)
2351 && INTEGRAL_TYPE_P (TREE_TYPE (op0)))
2353 tree inner_type = TREE_TYPE (op0);
2354 tree outer_type = type;
2356 /* Always use base-types here. This is important for the
2357 correct signedness. */
2358 if (TREE_TYPE (inner_type))
2359 inner_type = TREE_TYPE (inner_type);
2360 if (TREE_TYPE (outer_type))
2361 outer_type = TREE_TYPE (outer_type);
2363 /* If VR0 is varying and we increase the type precision, assume
2364 a full range for the following transformation. */
2365 if (vr0.type == VR_VARYING
2366 && TYPE_PRECISION (inner_type) < TYPE_PRECISION (outer_type))
2368 vr0.type = VR_RANGE;
2369 vr0.min = TYPE_MIN_VALUE (inner_type);
2370 vr0.max = TYPE_MAX_VALUE (inner_type);
2373 /* If VR0 is a constant range or anti-range and the conversion is
2374 not truncating we can convert the min and max values and
2375 canonicalize the resulting range. Otherwise we can do the
2376 conversion if the size of the range is less than what the
2377 precision of the target type can represent and the range is
2378 not an anti-range. */
2379 if ((vr0.type == VR_RANGE
2380 || vr0.type == VR_ANTI_RANGE)
2381 && TREE_CODE (vr0.min) == INTEGER_CST
2382 && TREE_CODE (vr0.max) == INTEGER_CST
2383 && !is_overflow_infinity (vr0.min)
2384 && !is_overflow_infinity (vr0.max)
2385 && (TYPE_PRECISION (outer_type) >= TYPE_PRECISION (inner_type)
2386 || (vr0.type == VR_RANGE
2387 && integer_zerop (int_const_binop (RSHIFT_EXPR,
2388 int_const_binop (MINUS_EXPR, vr0.max, vr0.min, 0),
2389 size_int (TYPE_PRECISION (outer_type)), 0)))))
2391 tree new_min, new_max;
2392 new_min = force_fit_type_double (outer_type,
2393 TREE_INT_CST_LOW (vr0.min),
2394 TREE_INT_CST_HIGH (vr0.min), 0, 0);
2395 new_max = force_fit_type_double (outer_type,
2396 TREE_INT_CST_LOW (vr0.max),
2397 TREE_INT_CST_HIGH (vr0.max), 0, 0);
2398 set_and_canonicalize_value_range (vr, vr0.type,
2399 new_min, new_max, NULL);
2403 set_value_range_to_varying (vr);
2407 /* Conversion of a VR_VARYING value to a wider type can result
2408 in a usable range. So wait until after we've handled conversions
2409 before dropping the result to VR_VARYING if we had a source
2410 operand that is VR_VARYING. */
2411 if (vr0.type == VR_VARYING)
2413 set_value_range_to_varying (vr);
2417 /* Apply the operation to each end of the range and see what we end
2419 if (code == NEGATE_EXPR
2420 && !TYPE_UNSIGNED (type))
2422 /* NEGATE_EXPR flips the range around. We need to treat
2423 TYPE_MIN_VALUE specially. */
2424 if (is_positive_overflow_infinity (vr0.max))
2425 min = negative_overflow_infinity (type);
2426 else if (is_negative_overflow_infinity (vr0.max))
2427 min = positive_overflow_infinity (type);
2428 else if (!vrp_val_is_min (vr0.max))
2429 min = fold_unary_to_constant (code, type, vr0.max);
2430 else if (needs_overflow_infinity (type))
2432 if (supports_overflow_infinity (type)
2433 && !is_overflow_infinity (vr0.min)
2434 && !vrp_val_is_min (vr0.min))
2435 min = positive_overflow_infinity (type);
2438 set_value_range_to_varying (vr);
2443 min = TYPE_MIN_VALUE (type);
2445 if (is_positive_overflow_infinity (vr0.min))
2446 max = negative_overflow_infinity (type);
2447 else if (is_negative_overflow_infinity (vr0.min))
2448 max = positive_overflow_infinity (type);
2449 else if (!vrp_val_is_min (vr0.min))
2450 max = fold_unary_to_constant (code, type, vr0.min);
2451 else if (needs_overflow_infinity (type))
2453 if (supports_overflow_infinity (type))
2454 max = positive_overflow_infinity (type);
2457 set_value_range_to_varying (vr);
2462 max = TYPE_MIN_VALUE (type);
2464 else if (code == NEGATE_EXPR
2465 && TYPE_UNSIGNED (type))
2467 if (!range_includes_zero_p (&vr0))
2469 max = fold_unary_to_constant (code, type, vr0.min);
2470 min = fold_unary_to_constant (code, type, vr0.max);
2474 if (range_is_null (&vr0))
2475 set_value_range_to_null (vr, type);
2477 set_value_range_to_varying (vr);
2481 else if (code == ABS_EXPR
2482 && !TYPE_UNSIGNED (type))
2484 /* -TYPE_MIN_VALUE = TYPE_MIN_VALUE with flag_wrapv so we can't get a
2486 if (!TYPE_OVERFLOW_UNDEFINED (type)
2487 && ((vr0.type == VR_RANGE
2488 && vrp_val_is_min (vr0.min))
2489 || (vr0.type == VR_ANTI_RANGE
2490 && !vrp_val_is_min (vr0.min)
2491 && !range_includes_zero_p (&vr0))))
2493 set_value_range_to_varying (vr);
2497 /* ABS_EXPR may flip the range around, if the original range
2498 included negative values. */
2499 if (is_overflow_infinity (vr0.min))
2500 min = positive_overflow_infinity (type);
2501 else if (!vrp_val_is_min (vr0.min))
2502 min = fold_unary_to_constant (code, type, vr0.min);
2503 else if (!needs_overflow_infinity (type))
2504 min = TYPE_MAX_VALUE (type);
2505 else if (supports_overflow_infinity (type))
2506 min = positive_overflow_infinity (type);
2509 set_value_range_to_varying (vr);
2513 if (is_overflow_infinity (vr0.max))
2514 max = positive_overflow_infinity (type);
2515 else if (!vrp_val_is_min (vr0.max))
2516 max = fold_unary_to_constant (code, type, vr0.max);
2517 else if (!needs_overflow_infinity (type))
2518 max = TYPE_MAX_VALUE (type);
2519 else if (supports_overflow_infinity (type))
2520 max = positive_overflow_infinity (type);
2523 set_value_range_to_varying (vr);
2527 cmp = compare_values (min, max);
2529 /* If a VR_ANTI_RANGEs contains zero, then we have
2530 ~[-INF, min(MIN, MAX)]. */
2531 if (vr0.type == VR_ANTI_RANGE)
2533 if (range_includes_zero_p (&vr0))
2535 /* Take the lower of the two values. */
2539 /* Create ~[-INF, min (abs(MIN), abs(MAX))]
2540 or ~[-INF + 1, min (abs(MIN), abs(MAX))] when
2541 flag_wrapv is set and the original anti-range doesn't include
2542 TYPE_MIN_VALUE, remember -TYPE_MIN_VALUE = TYPE_MIN_VALUE. */
2543 if (TYPE_OVERFLOW_WRAPS (type))
2545 tree type_min_value = TYPE_MIN_VALUE (type);
2547 min = (vr0.min != type_min_value
2548 ? int_const_binop (PLUS_EXPR, type_min_value,
2549 integer_one_node, 0)
2554 if (overflow_infinity_range_p (&vr0))
2555 min = negative_overflow_infinity (type);
2557 min = TYPE_MIN_VALUE (type);
2562 /* All else has failed, so create the range [0, INF], even for
2563 flag_wrapv since TYPE_MIN_VALUE is in the original
2565 vr0.type = VR_RANGE;
2566 min = build_int_cst (type, 0);
2567 if (needs_overflow_infinity (type))
2569 if (supports_overflow_infinity (type))
2570 max = positive_overflow_infinity (type);
2573 set_value_range_to_varying (vr);
2578 max = TYPE_MAX_VALUE (type);
2582 /* If the range contains zero then we know that the minimum value in the
2583 range will be zero. */
2584 else if (range_includes_zero_p (&vr0))
2588 min = build_int_cst (type, 0);
2592 /* If the range was reversed, swap MIN and MAX. */
2603 /* Otherwise, operate on each end of the range. */
2604 min = fold_unary_to_constant (code, type, vr0.min);
2605 max = fold_unary_to_constant (code, type, vr0.max);
2607 if (needs_overflow_infinity (type))
2609 gcc_assert (code != NEGATE_EXPR && code != ABS_EXPR);
2611 /* If both sides have overflowed, we don't know
2613 if ((is_overflow_infinity (vr0.min)
2614 || TREE_OVERFLOW (min))
2615 && (is_overflow_infinity (vr0.max)
2616 || TREE_OVERFLOW (max)))
2618 set_value_range_to_varying (vr);
2622 if (is_overflow_infinity (vr0.min))
2624 else if (TREE_OVERFLOW (min))
2626 if (supports_overflow_infinity (type))
2627 min = (tree_int_cst_sgn (min) >= 0
2628 ? positive_overflow_infinity (TREE_TYPE (min))
2629 : negative_overflow_infinity (TREE_TYPE (min)));
2632 set_value_range_to_varying (vr);
2637 if (is_overflow_infinity (vr0.max))
2639 else if (TREE_OVERFLOW (max))
2641 if (supports_overflow_infinity (type))
2642 max = (tree_int_cst_sgn (max) >= 0
2643 ? positive_overflow_infinity (TREE_TYPE (max))
2644 : negative_overflow_infinity (TREE_TYPE (max)));
2647 set_value_range_to_varying (vr);
2654 cmp = compare_values (min, max);
2655 if (cmp == -2 || cmp == 1)
2657 /* If the new range has its limits swapped around (MIN > MAX),
2658 then the operation caused one of them to wrap around, mark
2659 the new range VARYING. */
2660 set_value_range_to_varying (vr);
2663 set_value_range (vr, vr0.type, min, max, NULL);
2667 /* Extract range information from a conditional expression EXPR based on
2668 the ranges of each of its operands and the expression code. */
2671 extract_range_from_cond_expr (value_range_t *vr, tree expr)
2674 value_range_t vr0 = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
2675 value_range_t vr1 = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
2677 /* Get value ranges for each operand. For constant operands, create
2678 a new value range with the operand to simplify processing. */
2679 op0 = COND_EXPR_THEN (expr);
2680 if (TREE_CODE (op0) == SSA_NAME)
2681 vr0 = *(get_value_range (op0));
2682 else if (is_gimple_min_invariant (op0))
2683 set_value_range_to_value (&vr0, op0, NULL);
2685 set_value_range_to_varying (&vr0);
2687 op1 = COND_EXPR_ELSE (expr);
2688 if (TREE_CODE (op1) == SSA_NAME)
2689 vr1 = *(get_value_range (op1));
2690 else if (is_gimple_min_invariant (op1))
2691 set_value_range_to_value (&vr1, op1, NULL);
2693 set_value_range_to_varying (&vr1);
2695 /* The resulting value range is the union of the operand ranges */
2696 vrp_meet (&vr0, &vr1);
2697 copy_value_range (vr, &vr0);
2701 /* Extract range information from a comparison expression EXPR based
2702 on the range of its operand and the expression code. */
2705 extract_range_from_comparison (value_range_t *vr, enum tree_code code,
2706 tree type, tree op0, tree op1)
2709 tree val = vrp_evaluate_conditional_warnv_with_ops (code,
2714 /* A disadvantage of using a special infinity as an overflow
2715 representation is that we lose the ability to record overflow
2716 when we don't have an infinity. So we have to ignore a result
2717 which relies on overflow. */
2719 if (val && !is_overflow_infinity (val) && !sop)
2721 /* Since this expression was found on the RHS of an assignment,
2722 its type may be different from _Bool. Convert VAL to EXPR's
2724 val = fold_convert (type, val);
2725 if (is_gimple_min_invariant (val))
2726 set_value_range_to_value (vr, val, vr->equiv);
2728 set_value_range (vr, VR_RANGE, val, val, vr->equiv);
2731 /* The result of a comparison is always true or false. */
2732 set_value_range_to_truthvalue (vr, type);
2736 /* Try to compute a useful range out of expression EXPR and store it
2740 extract_range_from_expr (value_range_t *vr, tree expr)
2742 enum tree_code code = TREE_CODE (expr);
2744 if (code == ASSERT_EXPR)
2745 extract_range_from_assert (vr, expr);
2746 else if (code == SSA_NAME)
2747 extract_range_from_ssa_name (vr, expr);
2748 else if (TREE_CODE_CLASS (code) == tcc_binary
2749 || code == TRUTH_AND_EXPR
2750 || code == TRUTH_OR_EXPR
2751 || code == TRUTH_XOR_EXPR)
2752 extract_range_from_binary_expr (vr, TREE_CODE (expr), TREE_TYPE (expr),
2753 TREE_OPERAND (expr, 0),
2754 TREE_OPERAND (expr, 1));
2755 else if (TREE_CODE_CLASS (code) == tcc_unary)
2756 extract_range_from_unary_expr (vr, TREE_CODE (expr), TREE_TYPE (expr),
2757 TREE_OPERAND (expr, 0));
2758 else if (code == COND_EXPR)
2759 extract_range_from_cond_expr (vr, expr);
2760 else if (TREE_CODE_CLASS (code) == tcc_comparison)
2761 extract_range_from_comparison (vr, TREE_CODE (expr), TREE_TYPE (expr),
2762 TREE_OPERAND (expr, 0),
2763 TREE_OPERAND (expr, 1));
2764 else if (is_gimple_min_invariant (expr))
2765 set_value_range_to_value (vr, expr, NULL);
2767 set_value_range_to_varying (vr);
2769 /* If we got a varying range from the tests above, try a final
2770 time to derive a nonnegative or nonzero range. This time
2771 relying primarily on generic routines in fold in conjunction
2773 if (vr->type == VR_VARYING)
2777 if (INTEGRAL_TYPE_P (TREE_TYPE (expr))
2778 && vrp_expr_computes_nonnegative (expr, &sop))
2779 set_value_range_to_nonnegative (vr, TREE_TYPE (expr),
2780 sop || is_overflow_infinity (expr));
2781 else if (vrp_expr_computes_nonzero (expr, &sop)
2783 set_value_range_to_nonnull (vr, TREE_TYPE (expr));
2787 /* Given a range VR, a LOOP and a variable VAR, determine whether it
2788 would be profitable to adjust VR using scalar evolution information
2789 for VAR. If so, update VR with the new limits. */
2792 adjust_range_with_scev (value_range_t *vr, struct loop *loop, tree stmt,
2795 tree init, step, chrec, tmin, tmax, min, max, type;
2796 enum ev_direction dir;
2798 /* TODO. Don't adjust anti-ranges. An anti-range may provide
2799 better opportunities than a regular range, but I'm not sure. */
2800 if (vr->type == VR_ANTI_RANGE)
2803 /* Ensure that there are not values in the scev cache based on assumptions
2804 on ranges of ssa names that were changed
2805 (in set_value_range/set_value_range_to_varying). Preserve cached numbers
2806 of iterations, that were computed before the start of VRP (we do not
2807 recompute these each time to save the compile time). */
2808 scev_reset_except_niters ();
2810 chrec = instantiate_parameters (loop, analyze_scalar_evolution (loop, var));
2812 /* Like in PR19590, scev can return a constant function. */
2813 if (is_gimple_min_invariant (chrec))
2815 set_value_range_to_value (vr, chrec, vr->equiv);
2819 if (TREE_CODE (chrec) != POLYNOMIAL_CHREC)
2822 init = initial_condition_in_loop_num (chrec, loop->num);
2823 step = evolution_part_in_loop_num (chrec, loop->num);
2825 /* If STEP is symbolic, we can't know whether INIT will be the
2826 minimum or maximum value in the range. Also, unless INIT is
2827 a simple expression, compare_values and possibly other functions
2828 in tree-vrp won't be able to handle it. */
2829 if (step == NULL_TREE
2830 || !is_gimple_min_invariant (step)
2831 || !valid_value_p (init))
2834 dir = scev_direction (chrec);
2835 if (/* Do not adjust ranges if we do not know whether the iv increases
2836 or decreases, ... */
2837 dir == EV_DIR_UNKNOWN
2838 /* ... or if it may wrap. */
2839 || scev_probably_wraps_p (init, step, stmt, get_chrec_loop (chrec),
2843 /* We use TYPE_MIN_VALUE and TYPE_MAX_VALUE here instead of
2844 negative_overflow_infinity and positive_overflow_infinity,
2845 because we have concluded that the loop probably does not
2848 type = TREE_TYPE (var);
2849 if (POINTER_TYPE_P (type) || !TYPE_MIN_VALUE (type))
2850 tmin = lower_bound_in_type (type, type);
2852 tmin = TYPE_MIN_VALUE (type);
2853 if (POINTER_TYPE_P (type) || !TYPE_MAX_VALUE (type))
2854 tmax = upper_bound_in_type (type, type);
2856 tmax = TYPE_MAX_VALUE (type);
2858 if (vr->type == VR_VARYING || vr->type == VR_UNDEFINED)
2863 /* For VARYING or UNDEFINED ranges, just about anything we get
2864 from scalar evolutions should be better. */
2866 if (dir == EV_DIR_DECREASES)
2871 /* If we would create an invalid range, then just assume we
2872 know absolutely nothing. This may be over-conservative,
2873 but it's clearly safe, and should happen only in unreachable
2874 parts of code, or for invalid programs. */
2875 if (compare_values (min, max) == 1)
2878 set_value_range (vr, VR_RANGE, min, max, vr->equiv);
2880 else if (vr->type == VR_RANGE)
2885 if (dir == EV_DIR_DECREASES)
2887 /* INIT is the maximum value. If INIT is lower than VR->MAX
2888 but no smaller than VR->MIN, set VR->MAX to INIT. */
2889 if (compare_values (init, max) == -1)
2893 /* If we just created an invalid range with the minimum
2894 greater than the maximum, we fail conservatively.
2895 This should happen only in unreachable
2896 parts of code, or for invalid programs. */
2897 if (compare_values (min, max) == 1)
2901 /* According to the loop information, the variable does not
2902 overflow. If we think it does, probably because of an
2903 overflow due to arithmetic on a different INF value,
2905 if (is_negative_overflow_infinity (min))
2910 /* If INIT is bigger than VR->MIN, set VR->MIN to INIT. */
2911 if (compare_values (init, min) == 1)
2915 /* Again, avoid creating invalid range by failing. */
2916 if (compare_values (min, max) == 1)
2920 if (is_positive_overflow_infinity (max))
2924 set_value_range (vr, VR_RANGE, min, max, vr->equiv);
2928 /* Return true if VAR may overflow at STMT. This checks any available
2929 loop information to see if we can determine that VAR does not
2933 vrp_var_may_overflow (tree var, tree stmt)
2936 tree chrec, init, step;
2938 if (current_loops == NULL)
2941 l = loop_containing_stmt (stmt);
2945 chrec = instantiate_parameters (l, analyze_scalar_evolution (l, var));
2946 if (TREE_CODE (chrec) != POLYNOMIAL_CHREC)
2949 init = initial_condition_in_loop_num (chrec, l->num);
2950 step = evolution_part_in_loop_num (chrec, l->num);
2952 if (step == NULL_TREE
2953 || !is_gimple_min_invariant (step)
2954 || !valid_value_p (init))
2957 /* If we get here, we know something useful about VAR based on the
2958 loop information. If it wraps, it may overflow. */
2960 if (scev_probably_wraps_p (init, step, stmt, get_chrec_loop (chrec),
2964 if (dump_file && (dump_flags & TDF_DETAILS) != 0)
2966 print_generic_expr (dump_file, var, 0);
2967 fprintf (dump_file, ": loop information indicates does not overflow\n");
2974 /* Given two numeric value ranges VR0, VR1 and a comparison code COMP:
2976 - Return BOOLEAN_TRUE_NODE if VR0 COMP VR1 always returns true for
2977 all the values in the ranges.
2979 - Return BOOLEAN_FALSE_NODE if the comparison always returns false.
2981 - Return NULL_TREE if it is not always possible to determine the
2982 value of the comparison.
2984 Also set *STRICT_OVERFLOW_P to indicate whether a range with an
2985 overflow infinity was used in the test. */
2989 compare_ranges (enum tree_code comp, value_range_t *vr0, value_range_t *vr1,
2990 bool *strict_overflow_p)
2992 /* VARYING or UNDEFINED ranges cannot be compared. */
2993 if (vr0->type == VR_VARYING
2994 || vr0->type == VR_UNDEFINED
2995 || vr1->type == VR_VARYING
2996 || vr1->type == VR_UNDEFINED)
2999 /* Anti-ranges need to be handled separately. */
3000 if (vr0->type == VR_ANTI_RANGE || vr1->type == VR_ANTI_RANGE)
3002 /* If both are anti-ranges, then we cannot compute any
3004 if (vr0->type == VR_ANTI_RANGE && vr1->type == VR_ANTI_RANGE)
3007 /* These comparisons are never statically computable. */
3014 /* Equality can be computed only between a range and an
3015 anti-range. ~[VAL1, VAL2] == [VAL1, VAL2] is always false. */
3016 if (vr0->type == VR_RANGE)
3018 /* To simplify processing, make VR0 the anti-range. */
3019 value_range_t *tmp = vr0;
3024 gcc_assert (comp == NE_EXPR || comp == EQ_EXPR);
3026 if (compare_values_warnv (vr0->min, vr1->min, strict_overflow_p) == 0
3027 && compare_values_warnv (vr0->max, vr1->max, strict_overflow_p) == 0)
3028 return (comp == NE_EXPR) ? boolean_true_node : boolean_false_node;
3033 if (!usable_range_p (vr0, strict_overflow_p)
3034 || !usable_range_p (vr1, strict_overflow_p))
3037 /* Simplify processing. If COMP is GT_EXPR or GE_EXPR, switch the
3038 operands around and change the comparison code. */
3039 if (comp == GT_EXPR || comp == GE_EXPR)
3042 comp = (comp == GT_EXPR) ? LT_EXPR : LE_EXPR;
3048 if (comp == EQ_EXPR)
3050 /* Equality may only be computed if both ranges represent
3051 exactly one value. */
3052 if (compare_values_warnv (vr0->min, vr0->max, strict_overflow_p) == 0
3053 && compare_values_warnv (vr1->min, vr1->max, strict_overflow_p) == 0)
3055 int cmp_min = compare_values_warnv (vr0->min, vr1->min,
3057 int cmp_max = compare_values_warnv (vr0->max, vr1->max,
3059 if (cmp_min == 0 && cmp_max == 0)
3060 return boolean_true_node;
3061 else if (cmp_min != -2 && cmp_max != -2)
3062 return boolean_false_node;
3064 /* If [V0_MIN, V1_MAX] < [V1_MIN, V1_MAX] then V0 != V1. */
3065 else if (compare_values_warnv (vr0->min, vr1->max,
3066 strict_overflow_p) == 1
3067 || compare_values_warnv (vr1->min, vr0->max,
3068 strict_overflow_p) == 1)
3069 return boolean_false_node;
3073 else if (comp == NE_EXPR)
3077 /* If VR0 is completely to the left or completely to the right
3078 of VR1, they are always different. Notice that we need to
3079 make sure that both comparisons yield similar results to
3080 avoid comparing values that cannot be compared at
3082 cmp1 = compare_values_warnv (vr0->max, vr1->min, strict_overflow_p);
3083 cmp2 = compare_values_warnv (vr0->min, vr1->max, strict_overflow_p);
3084 if ((cmp1 == -1 && cmp2 == -1) || (cmp1 == 1 && cmp2 == 1))
3085 return boolean_true_node;
3087 /* If VR0 and VR1 represent a single value and are identical,
3089 else if (compare_values_warnv (vr0->min, vr0->max,
3090 strict_overflow_p) == 0
3091 && compare_values_warnv (vr1->min, vr1->max,
3092 strict_overflow_p) == 0
3093 && compare_values_warnv (vr0->min, vr1->min,
3094 strict_overflow_p) == 0
3095 && compare_values_warnv (vr0->max, vr1->max,
3096 strict_overflow_p) == 0)
3097 return boolean_false_node;
3099 /* Otherwise, they may or may not be different. */
3103 else if (comp == LT_EXPR || comp == LE_EXPR)
3107 /* If VR0 is to the left of VR1, return true. */
3108 tst = compare_values_warnv (vr0->max, vr1->min, strict_overflow_p);
3109 if ((comp == LT_EXPR && tst == -1)
3110 || (comp == LE_EXPR && (tst == -1 || tst == 0)))
3112 if (overflow_infinity_range_p (vr0)
3113 || overflow_infinity_range_p (vr1))
3114 *strict_overflow_p = true;
3115 return boolean_true_node;
3118 /* If VR0 is to the right of VR1, return false. */
3119 tst = compare_values_warnv (vr0->min, vr1->max, strict_overflow_p);
3120 if ((comp == LT_EXPR && (tst == 0 || tst == 1))
3121 || (comp == LE_EXPR && tst == 1))
3123 if (overflow_infinity_range_p (vr0)
3124 || overflow_infinity_range_p (vr1))
3125 *strict_overflow_p = true;
3126 return boolean_false_node;
3129 /* Otherwise, we don't know. */
3137 /* Given a value range VR, a value VAL and a comparison code COMP, return
3138 BOOLEAN_TRUE_NODE if VR COMP VAL always returns true for all the
3139 values in VR. Return BOOLEAN_FALSE_NODE if the comparison
3140 always returns false. Return NULL_TREE if it is not always
3141 possible to determine the value of the comparison. Also set
3142 *STRICT_OVERFLOW_P to indicate whether a range with an overflow
3143 infinity was used in the test. */
3146 compare_range_with_value (enum tree_code comp, value_range_t *vr, tree val,
3147 bool *strict_overflow_p)
3149 if (vr->type == VR_VARYING || vr->type == VR_UNDEFINED)
3152 /* Anti-ranges need to be handled separately. */
3153 if (vr->type == VR_ANTI_RANGE)
3155 /* For anti-ranges, the only predicates that we can compute at
3156 compile time are equality and inequality. */
3163 /* ~[VAL_1, VAL_2] OP VAL is known if VAL_1 <= VAL <= VAL_2. */
3164 if (value_inside_range (val, vr) == 1)
3165 return (comp == NE_EXPR) ? boolean_true_node : boolean_false_node;
3170 if (!usable_range_p (vr, strict_overflow_p))
3173 if (comp == EQ_EXPR)
3175 /* EQ_EXPR may only be computed if VR represents exactly
3177 if (compare_values_warnv (vr->min, vr->max, strict_overflow_p) == 0)
3179 int cmp = compare_values_warnv (vr->min, val, strict_overflow_p);
3181 return boolean_true_node;
3182 else if (cmp == -1 || cmp == 1 || cmp == 2)
3183 return boolean_false_node;
3185 else if (compare_values_warnv (val, vr->min, strict_overflow_p) == -1
3186 || compare_values_warnv (vr->max, val, strict_overflow_p) == -1)
3187 return boolean_false_node;
3191 else if (comp == NE_EXPR)
3193 /* If VAL is not inside VR, then they are always different. */
3194 if (compare_values_warnv (vr->max, val, strict_overflow_p) == -1
3195 || compare_values_warnv (vr->min, val, strict_overflow_p) == 1)
3196 return boolean_true_node;
3198 /* If VR represents exactly one value equal to VAL, then return
3200 if (compare_values_warnv (vr->min, vr->max, strict_overflow_p) == 0
3201 && compare_values_warnv (vr->min, val, strict_overflow_p) == 0)
3202 return boolean_false_node;
3204 /* Otherwise, they may or may not be different. */
3207 else if (comp == LT_EXPR || comp == LE_EXPR)
3211 /* If VR is to the left of VAL, return true. */
3212 tst = compare_values_warnv (vr->max, val, strict_overflow_p);
3213 if ((comp == LT_EXPR && tst == -1)
3214 || (comp == LE_EXPR && (tst == -1 || tst == 0)))
3216 if (overflow_infinity_range_p (vr))
3217 *strict_overflow_p = true;
3218 return boolean_true_node;
3221 /* If VR is to the right of VAL, return false. */
3222 tst = compare_values_warnv (vr->min, val, strict_overflow_p);
3223 if ((comp == LT_EXPR && (tst == 0 || tst == 1))
3224 || (comp == LE_EXPR && tst == 1))
3226 if (overflow_infinity_range_p (vr))
3227 *strict_overflow_p = true;
3228 return boolean_false_node;
3231 /* Otherwise, we don't know. */
3234 else if (comp == GT_EXPR || comp == GE_EXPR)
3238 /* If VR is to the right of VAL, return true. */
3239 tst = compare_values_warnv (vr->min, val, strict_overflow_p);
3240 if ((comp == GT_EXPR && tst == 1)
3241 || (comp == GE_EXPR && (tst == 0 || tst == 1)))
3243 if (overflow_infinity_range_p (vr))
3244 *strict_overflow_p = true;
3245 return boolean_true_node;
3248 /* If VR is to the left of VAL, return false. */
3249 tst = compare_values_warnv (vr->max, val, strict_overflow_p);
3250 if ((comp == GT_EXPR && (tst == -1 || tst == 0))
3251 || (comp == GE_EXPR && tst == -1))
3253 if (overflow_infinity_range_p (vr))
3254 *strict_overflow_p = true;
3255 return boolean_false_node;
3258 /* Otherwise, we don't know. */
3266 /* Debugging dumps. */
3268 void dump_value_range (FILE *, value_range_t *);
3269 void debug_value_range (value_range_t *);
3270 void dump_all_value_ranges (FILE *);
3271 void debug_all_value_ranges (void);
3272 void dump_vr_equiv (FILE *, bitmap);
3273 void debug_vr_equiv (bitmap);
3276 /* Dump value range VR to FILE. */
3279 dump_value_range (FILE *file, value_range_t *vr)
3282 fprintf (file, "[]");
3283 else if (vr->type == VR_UNDEFINED)
3284 fprintf (file, "UNDEFINED");
3285 else if (vr->type == VR_RANGE || vr->type == VR_ANTI_RANGE)
3287 tree type = TREE_TYPE (vr->min);
3289 fprintf (file, "%s[", (vr->type == VR_ANTI_RANGE) ? "~" : "");
3291 if (is_negative_overflow_infinity (vr->min))
3292 fprintf (file, "-INF(OVF)");
3293 else if (INTEGRAL_TYPE_P (type)
3294 && !TYPE_UNSIGNED (type)
3295 && vrp_val_is_min (vr->min))
3296 fprintf (file, "-INF");
3298 print_generic_expr (file, vr->min, 0);
3300 fprintf (file, ", ");
3302 if (is_positive_overflow_infinity (vr->max))
3303 fprintf (file, "+INF(OVF)");
3304 else if (INTEGRAL_TYPE_P (type)
3305 && vrp_val_is_max (vr->max))
3306 fprintf (file, "+INF");
3308 print_generic_expr (file, vr->max, 0);
3310 fprintf (file, "]");
3317 fprintf (file, " EQUIVALENCES: { ");
3319 EXECUTE_IF_SET_IN_BITMAP (vr->equiv, 0, i, bi)
3321 print_generic_expr (file, ssa_name (i), 0);
3322 fprintf (file, " ");
3326 fprintf (file, "} (%u elements)", c);
3329 else if (vr->type == VR_VARYING)
3330 fprintf (file, "VARYING");
3332 fprintf (file, "INVALID RANGE");
3336 /* Dump value range VR to stderr. */
3339 debug_value_range (value_range_t *vr)
3341 dump_value_range (stderr, vr);
3342 fprintf (stderr, "\n");
3346 /* Dump value ranges of all SSA_NAMEs to FILE. */
3349 dump_all_value_ranges (FILE *file)
3353 for (i = 0; i < num_ssa_names; i++)
3357 print_generic_expr (file, ssa_name (i), 0);
3358 fprintf (file, ": ");
3359 dump_value_range (file, vr_value[i]);
3360 fprintf (file, "\n");
3364 fprintf (file, "\n");
3368 /* Dump all value ranges to stderr. */
3371 debug_all_value_ranges (void)
3373 dump_all_value_ranges (stderr);
3377 /* Given a COND_EXPR COND of the form 'V OP W', and an SSA name V,
3378 create a new SSA name N and return the assertion assignment
3379 'V = ASSERT_EXPR <V, V OP W>'. */
3382 build_assert_expr_for (tree cond, tree v)
3386 gcc_assert (TREE_CODE (v) == SSA_NAME);
3387 n = duplicate_ssa_name (v, NULL_TREE);
3389 if (COMPARISON_CLASS_P (cond))
3391 tree a = build2 (ASSERT_EXPR, TREE_TYPE (v), v, cond);
3392 assertion = build_gimple_modify_stmt (n, a);
3394 else if (TREE_CODE (cond) == TRUTH_NOT_EXPR)
3396 /* Given !V, build the assignment N = false. */
3397 tree op0 = TREE_OPERAND (cond, 0);
3398 gcc_assert (op0 == v);
3399 assertion = build_gimple_modify_stmt (n, boolean_false_node);
3401 else if (TREE_CODE (cond) == SSA_NAME)
3403 /* Given V, build the assignment N = true. */
3404 gcc_assert (v == cond);
3405 assertion = build_gimple_modify_stmt (n, boolean_true_node);
3410 SSA_NAME_DEF_STMT (n) = assertion;
3412 /* The new ASSERT_EXPR, creates a new SSA name that replaces the
3413 operand of the ASSERT_EXPR. Register the new name and the old one
3414 in the replacement table so that we can fix the SSA web after
3415 adding all the ASSERT_EXPRs. */
3416 register_new_name_mapping (n, v);
3422 /* Return false if EXPR is a predicate expression involving floating
3426 fp_predicate (const_tree expr)
3428 return (COMPARISON_CLASS_P (expr)
3429 && FLOAT_TYPE_P (TREE_TYPE (TREE_OPERAND (expr, 0))));
3433 /* If the range of values taken by OP can be inferred after STMT executes,
3434 return the comparison code (COMP_CODE_P) and value (VAL_P) that
3435 describes the inferred range. Return true if a range could be
3439 infer_value_range (tree stmt, tree op, enum tree_code *comp_code_p, tree *val_p)
3442 *comp_code_p = ERROR_MARK;
3444 /* Do not attempt to infer anything in names that flow through
3446 if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (op))
3449 /* Similarly, don't infer anything from statements that may throw
3451 if (tree_could_throw_p (stmt))
3454 /* If STMT is the last statement of a basic block with no
3455 successors, there is no point inferring anything about any of its
3456 operands. We would not be able to find a proper insertion point
3457 for the assertion, anyway. */
3458 if (stmt_ends_bb_p (stmt) && EDGE_COUNT (bb_for_stmt (stmt)->succs) == 0)
3461 /* We can only assume that a pointer dereference will yield
3462 non-NULL if -fdelete-null-pointer-checks is enabled. */
3463 if (flag_delete_null_pointer_checks && POINTER_TYPE_P (TREE_TYPE (op)))
3465 unsigned num_uses, num_loads, num_stores;
3467 count_uses_and_derefs (op, stmt, &num_uses, &num_loads, &num_stores);
3468 if (num_loads + num_stores > 0)
3470 *val_p = build_int_cst (TREE_TYPE (op), 0);
3471 *comp_code_p = NE_EXPR;
3480 void dump_asserts_for (FILE *, tree);
3481 void debug_asserts_for (tree);
3482 void dump_all_asserts (FILE *);
3483 void debug_all_asserts (void);
3485 /* Dump all the registered assertions for NAME to FILE. */
3488 dump_asserts_for (FILE *file, tree name)
3492 fprintf (file, "Assertions to be inserted for ");
3493 print_generic_expr (file, name, 0);
3494 fprintf (file, "\n");
3496 loc = asserts_for[SSA_NAME_VERSION (name)];
3499 fprintf (file, "\t");
3500 print_generic_expr (file, bsi_stmt (loc->si), 0);
3501 fprintf (file, "\n\tBB #%d", loc->bb->index);
3504 fprintf (file, "\n\tEDGE %d->%d", loc->e->src->index,
3505 loc->e->dest->index);
3506 dump_edge_info (file, loc->e, 0);
3508 fprintf (file, "\n\tPREDICATE: ");
3509 print_generic_expr (file, name, 0);
3510 fprintf (file, " %s ", tree_code_name[(int)loc->comp_code]);
3511 print_generic_expr (file, loc->val, 0);
3512 fprintf (file, "\n\n");
3516 fprintf (file, "\n");
3520 /* Dump all the registered assertions for NAME to stderr. */
3523 debug_asserts_for (tree name)
3525 dump_asserts_for (stderr, name);
3529 /* Dump all the registered assertions for all the names to FILE. */
3532 dump_all_asserts (FILE *file)
3537 fprintf (file, "\nASSERT_EXPRs to be inserted\n\n");
3538 EXECUTE_IF_SET_IN_BITMAP (need_assert_for, 0, i, bi)
3539 dump_asserts_for (file, ssa_name (i));
3540 fprintf (file, "\n");
3544 /* Dump all the registered assertions for all the names to stderr. */
3547 debug_all_asserts (void)
3549 dump_all_asserts (stderr);
3553 /* If NAME doesn't have an ASSERT_EXPR registered for asserting
3554 'EXPR COMP_CODE VAL' at a location that dominates block BB or
3555 E->DEST, then register this location as a possible insertion point
3556 for ASSERT_EXPR <NAME, EXPR COMP_CODE VAL>.
3558 BB, E and SI provide the exact insertion point for the new
3559 ASSERT_EXPR. If BB is NULL, then the ASSERT_EXPR is to be inserted
3560 on edge E. Otherwise, if E is NULL, the ASSERT_EXPR is inserted on
3561 BB. If SI points to a COND_EXPR or a SWITCH_EXPR statement, then E
3562 must not be NULL. */
3565 register_new_assert_for (tree name, tree expr,
3566 enum tree_code comp_code,
3570 block_stmt_iterator si)
3572 assert_locus_t n, loc, last_loc;
3574 basic_block dest_bb;
3576 #if defined ENABLE_CHECKING
3577 gcc_assert (bb == NULL || e == NULL);
3580 gcc_assert (TREE_CODE (bsi_stmt (si)) != COND_EXPR
3581 && TREE_CODE (bsi_stmt (si)) != SWITCH_EXPR);
3584 /* The new assertion A will be inserted at BB or E. We need to
3585 determine if the new location is dominated by a previously
3586 registered location for A. If we are doing an edge insertion,
3587 assume that A will be inserted at E->DEST. Note that this is not
3590 If E is a critical edge, it will be split. But even if E is
3591 split, the new block will dominate the same set of blocks that
3594 The reverse, however, is not true, blocks dominated by E->DEST
3595 will not be dominated by the new block created to split E. So,
3596 if the insertion location is on a critical edge, we will not use
3597 the new location to move another assertion previously registered
3598 at a block dominated by E->DEST. */
3599 dest_bb = (bb) ? bb : e->dest;
3601 /* If NAME already has an ASSERT_EXPR registered for COMP_CODE and
3602 VAL at a block dominating DEST_BB, then we don't need to insert a new
3603 one. Similarly, if the same assertion already exists at a block
3604 dominated by DEST_BB and the new location is not on a critical
3605 edge, then update the existing location for the assertion (i.e.,
3606 move the assertion up in the dominance tree).
3608 Note, this is implemented as a simple linked list because there
3609 should not be more than a handful of assertions registered per
3610 name. If this becomes a performance problem, a table hashed by
3611 COMP_CODE and VAL could be implemented. */
3612 loc = asserts_for[SSA_NAME_VERSION (name)];
3617 if (loc->comp_code == comp_code
3619 || operand_equal_p (loc->val, val, 0))
3620 && (loc->expr == expr
3621 || operand_equal_p (loc->expr, expr, 0)))
3623 /* If the assertion NAME COMP_CODE VAL has already been
3624 registered at a basic block that dominates DEST_BB, then
3625 we don't need to insert the same assertion again. Note
3626 that we don't check strict dominance here to avoid
3627 replicating the same assertion inside the same basic
3628 block more than once (e.g., when a pointer is
3629 dereferenced several times inside a block).
3631 An exception to this rule are edge insertions. If the
3632 new assertion is to be inserted on edge E, then it will
3633 dominate all the other insertions that we may want to
3634 insert in DEST_BB. So, if we are doing an edge
3635 insertion, don't do this dominance check. */
3637 && dominated_by_p (CDI_DOMINATORS, dest_bb, loc->bb))
3640 /* Otherwise, if E is not a critical edge and DEST_BB
3641 dominates the existing location for the assertion, move
3642 the assertion up in the dominance tree by updating its
3643 location information. */
3644 if ((e == NULL || !EDGE_CRITICAL_P (e))
3645 && dominated_by_p (CDI_DOMINATORS, loc->bb, dest_bb))
3654 /* Update the last node of the list and move to the next one. */
3659 /* If we didn't find an assertion already registered for
3660 NAME COMP_CODE VAL, add a new one at the end of the list of
3661 assertions associated with NAME. */
3662 n = XNEW (struct assert_locus_d);
3666 n->comp_code = comp_code;
3674 asserts_for[SSA_NAME_VERSION (name)] = n;
3676 bitmap_set_bit (need_assert_for, SSA_NAME_VERSION (name));
3679 /* (COND_OP0 COND_CODE COND_OP1) is a predicate which uses NAME.
3680 Extract a suitable test code and value and store them into *CODE_P and
3681 *VAL_P so the predicate is normalized to NAME *CODE_P *VAL_P.
3683 If no extraction was possible, return FALSE, otherwise return TRUE.
3685 If INVERT is true, then we invert the result stored into *CODE_P. */
3688 extract_code_and_val_from_cond_with_ops (tree name, enum tree_code cond_code,
3689 tree cond_op0, tree cond_op1,
3690 bool invert, enum tree_code *code_p,
3693 enum tree_code comp_code;
3696 /* Otherwise, we have a comparison of the form NAME COMP VAL
3697 or VAL COMP NAME. */
3698 if (name == cond_op1)
3700 /* If the predicate is of the form VAL COMP NAME, flip
3701 COMP around because we need to register NAME as the
3702 first operand in the predicate. */
3703 comp_code = swap_tree_comparison (cond_code);
3708 /* The comparison is of the form NAME COMP VAL, so the
3709 comparison code remains unchanged. */
3710 comp_code = cond_code;
3714 /* Invert the comparison code as necessary. */
3716 comp_code = invert_tree_comparison (comp_code, 0);
3718 /* VRP does not handle float types. */
3719 if (SCALAR_FLOAT_TYPE_P (TREE_TYPE (val)))
3722 /* Do not register always-false predicates.
3723 FIXME: this works around a limitation in fold() when dealing with
3724 enumerations. Given 'enum { N1, N2 } x;', fold will not
3725 fold 'if (x > N2)' to 'if (0)'. */
3726 if ((comp_code == GT_EXPR || comp_code == LT_EXPR)
3727 && INTEGRAL_TYPE_P (TREE_TYPE (val)))
3729 tree min = TYPE_MIN_VALUE (TREE_TYPE (val));
3730 tree max = TYPE_MAX_VALUE (TREE_TYPE (val));
3732 if (comp_code == GT_EXPR
3734 || compare_values (val, max) == 0))
3737 if (comp_code == LT_EXPR
3739 || compare_values (val, min) == 0))
3742 *code_p = comp_code;
3747 /* Try to register an edge assertion for SSA name NAME on edge E for
3748 the condition COND contributing to the conditional jump pointed to by BSI.
3749 Invert the condition COND if INVERT is true.
3750 Return true if an assertion for NAME could be registered. */
3753 register_edge_assert_for_2 (tree name, edge e, block_stmt_iterator bsi,
3754 enum tree_code cond_code,
3755 tree cond_op0, tree cond_op1, bool invert)
3758 enum tree_code comp_code;
3759 bool retval = false;
3761 if (!extract_code_and_val_from_cond_with_ops (name, cond_code,
3764 invert, &comp_code, &val))
3767 /* Only register an ASSERT_EXPR if NAME was found in the sub-graph
3768 reachable from E. */
3769 if (TEST_BIT (found_in_subgraph, SSA_NAME_VERSION (name))
3770 && !has_single_use (name))
3772 register_new_assert_for (name, name, comp_code, val, NULL, e, bsi);
3776 /* In the case of NAME <= CST and NAME being defined as
3777 NAME = (unsigned) NAME2 + CST2 we can assert NAME2 >= -CST2
3778 and NAME2 <= CST - CST2. We can do the same for NAME > CST.
3779 This catches range and anti-range tests. */
3780 if ((comp_code == LE_EXPR
3781 || comp_code == GT_EXPR)
3782 && TREE_CODE (val) == INTEGER_CST
3783 && TYPE_UNSIGNED (TREE_TYPE (val)))
3785 tree def_stmt = SSA_NAME_DEF_STMT (name);
3786 tree cst2 = NULL_TREE, name2 = NULL_TREE, name3 = NULL_TREE;
3788 /* Extract CST2 from the (optional) addition. */
3789 if (TREE_CODE (def_stmt) == GIMPLE_MODIFY_STMT
3790 && TREE_CODE (GIMPLE_STMT_OPERAND (def_stmt, 1)) == PLUS_EXPR)
3792 name2 = TREE_OPERAND (GIMPLE_STMT_OPERAND (def_stmt, 1), 0);
3793 cst2 = TREE_OPERAND (GIMPLE_STMT_OPERAND (def_stmt, 1), 1);
3794 if (TREE_CODE (name2) == SSA_NAME
3795 && TREE_CODE (cst2) == INTEGER_CST)
3796 def_stmt = SSA_NAME_DEF_STMT (name2);
3799 /* Extract NAME2 from the (optional) sign-changing cast. */
3800 if (TREE_CODE (def_stmt) == GIMPLE_MODIFY_STMT
3801 && (TREE_CODE (GIMPLE_STMT_OPERAND (def_stmt, 1)) == NOP_EXPR
3802 || TREE_CODE (GIMPLE_STMT_OPERAND (def_stmt, 1)) == CONVERT_EXPR))
3804 tree rhs = GIMPLE_STMT_OPERAND (def_stmt, 1);
3805 if ((TREE_CODE (rhs) == NOP_EXPR
3806 || TREE_CODE (rhs) == CONVERT_EXPR)
3807 && ! TYPE_UNSIGNED (TREE_TYPE (TREE_OPERAND (rhs, 0)))
3808 && (TYPE_PRECISION (TREE_TYPE (rhs))
3809 == TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (rhs, 0)))))
3810 name3 = TREE_OPERAND (GIMPLE_STMT_OPERAND (def_stmt, 1), 0);
3813 /* If name3 is used later, create an ASSERT_EXPR for it. */
3814 if (name3 != NULL_TREE
3815 && TREE_CODE (name3) == SSA_NAME
3816 && (cst2 == NULL_TREE
3817 || TREE_CODE (cst2) == INTEGER_CST)
3818 && INTEGRAL_TYPE_P (TREE_TYPE (name3))
3819 && TEST_BIT (found_in_subgraph, SSA_NAME_VERSION (name3))
3820 && !has_single_use (name3))
3824 /* Build an expression for the range test. */
3825 tmp = build1 (NOP_EXPR, TREE_TYPE (name), name3);
3826 if (cst2 != NULL_TREE)
3827 tmp = build2 (PLUS_EXPR, TREE_TYPE (name), tmp, cst2);
3831 fprintf (dump_file, "Adding assert for ");
3832 print_generic_expr (dump_file, name3, 0);
3833 fprintf (dump_file, " from ");
3834 print_generic_expr (dump_file, tmp, 0);
3835 fprintf (dump_file, "\n");
3838 register_new_assert_for (name3, tmp, comp_code, val, NULL, e, bsi);
3843 /* If name2 is used later, create an ASSERT_EXPR for it. */
3844 if (name2 != NULL_TREE
3845 && TREE_CODE (name2) == SSA_NAME
3846 && TREE_CODE (cst2) == INTEGER_CST
3847 && INTEGRAL_TYPE_P (TREE_TYPE (name2))
3848 && TEST_BIT (found_in_subgraph, SSA_NAME_VERSION (name2))
3849 && !has_single_use (name2))
3853 /* Build an expression for the range test. */
3855 if (TREE_TYPE (name) != TREE_TYPE (name2))
3856 tmp = build1 (NOP_EXPR, TREE_TYPE (name), tmp);
3857 if (cst2 != NULL_TREE)
3858 tmp = build2 (PLUS_EXPR, TREE_TYPE (name), tmp, cst2);
3862 fprintf (dump_file, "Adding assert for ");
3863 print_generic_expr (dump_file, name2, 0);
3864 fprintf (dump_file, " from ");
3865 print_generic_expr (dump_file, tmp, 0);
3866 fprintf (dump_file, "\n");
3869 register_new_assert_for (name2, tmp, comp_code, val, NULL, e, bsi);
3878 /* OP is an operand of a truth value expression which is known to have
3879 a particular value. Register any asserts for OP and for any
3880 operands in OP's defining statement.
3882 If CODE is EQ_EXPR, then we want to register OP is zero (false),
3883 if CODE is NE_EXPR, then we want to register OP is nonzero (true). */
3886 register_edge_assert_for_1 (tree op, enum tree_code code,
3887 edge e, block_stmt_iterator bsi)
3889 bool retval = false;
3890 tree op_def, rhs, val;
3891 enum tree_code rhs_code;
3893 /* We only care about SSA_NAMEs. */
3894 if (TREE_CODE (op) != SSA_NAME)
3897 /* We know that OP will have a zero or nonzero value. If OP is used
3898 more than once go ahead and register an assert for OP.
3900 The FOUND_IN_SUBGRAPH support is not helpful in this situation as
3901 it will always be set for OP (because OP is used in a COND_EXPR in
3903 if (!has_single_use (op))
3905 val = build_int_cst (TREE_TYPE (op), 0);
3906 register_new_assert_for (op, op, code, val, NULL, e, bsi);
3910 /* Now look at how OP is set. If it's set from a comparison,
3911 a truth operation or some bit operations, then we may be able
3912 to register information about the operands of that assignment. */
3913 op_def = SSA_NAME_DEF_STMT (op);
3914 if (TREE_CODE (op_def) != GIMPLE_MODIFY_STMT)
3917 rhs = GIMPLE_STMT_OPERAND (op_def, 1);
3918 rhs_code = TREE_CODE (rhs);
3920 if (COMPARISON_CLASS_P (rhs))
3922 bool invert = (code == EQ_EXPR ? true : false);
3923 tree op0 = TREE_OPERAND (rhs, 0);
3924 tree op1 = TREE_OPERAND (rhs, 1);
3926 if (TREE_CODE (op0) == SSA_NAME)
3927 retval |= register_edge_assert_for_2 (op0, e, bsi, rhs_code, op0, op1,
3929 if (TREE_CODE (op1) == SSA_NAME)
3930 retval |= register_edge_assert_for_2 (op1, e, bsi, rhs_code, op0, op1,
3933 else if ((code == NE_EXPR
3934 && (TREE_CODE (rhs) == TRUTH_AND_EXPR
3935 || TREE_CODE (rhs) == BIT_AND_EXPR))
3937 && (TREE_CODE (rhs) == TRUTH_OR_EXPR
3938 || TREE_CODE (rhs) == BIT_IOR_EXPR)))
3940 /* Recurse on each operand. */
3941 retval |= register_edge_assert_for_1 (TREE_OPERAND (rhs, 0),
3943 retval |= register_edge_assert_for_1 (TREE_OPERAND (rhs, 1),
3946 else if (TREE_CODE (rhs) == TRUTH_NOT_EXPR)
3948 /* Recurse, flipping CODE. */
3949 code = invert_tree_comparison (code, false);
3950 retval |= register_edge_assert_for_1 (TREE_OPERAND (rhs, 0),
3953 else if (TREE_CODE (rhs) == SSA_NAME)
3955 /* Recurse through the copy. */
3956 retval |= register_edge_assert_for_1 (rhs, code, e, bsi);
3958 else if (TREE_CODE (rhs) == NOP_EXPR
3959 || TREE_CODE (rhs) == CONVERT_EXPR)
3961 /* Recurse through the type conversion. */
3962 retval |= register_edge_assert_for_1 (TREE_OPERAND (rhs, 0),
3969 /* Try to register an edge assertion for SSA name NAME on edge E for
3970 the condition COND contributing to the conditional jump pointed to by SI.
3971 Return true if an assertion for NAME could be registered. */
3974 register_edge_assert_for (tree name, edge e, block_stmt_iterator si,
3975 enum tree_code cond_code, tree cond_op0,
3979 enum tree_code comp_code;
3980 bool retval = false;
3981 bool is_else_edge = (e->flags & EDGE_FALSE_VALUE) != 0;
3983 /* Do not attempt to infer anything in names that flow through
3985 if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (name))
3988 if (!extract_code_and_val_from_cond_with_ops (name, cond_code,
3994 /* Register ASSERT_EXPRs for name. */
3995 retval |= register_edge_assert_for_2 (name, e, si, cond_code, cond_op0,
3996 cond_op1, is_else_edge);
3999 /* If COND is effectively an equality test of an SSA_NAME against
4000 the value zero or one, then we may be able to assert values
4001 for SSA_NAMEs which flow into COND. */
4003 /* In the case of NAME == 1 or NAME != 0, for TRUTH_AND_EXPR defining
4004 statement of NAME we can assert both operands of the TRUTH_AND_EXPR
4005 have nonzero value. */
4006 if (((comp_code == EQ_EXPR && integer_onep (val))
4007 || (comp_code == NE_EXPR && integer_zerop (val))))
4009 tree def_stmt = SSA_NAME_DEF_STMT (name);
4011 if (TREE_CODE (def_stmt) == GIMPLE_MODIFY_STMT
4012 && (TREE_CODE (GIMPLE_STMT_OPERAND (def_stmt, 1)) == TRUTH_AND_EXPR
4013 || TREE_CODE (GIMPLE_STMT_OPERAND (def_stmt, 1)) == BIT_AND_EXPR))
4015 tree op0 = TREE_OPERAND (GIMPLE_STMT_OPERAND (def_stmt, 1), 0);
4016 tree op1 = TREE_OPERAND (GIMPLE_STMT_OPERAND (def_stmt, 1), 1);
4017 retval |= register_edge_assert_for_1 (op0, NE_EXPR, e, si);
4018 retval |= register_edge_assert_for_1 (op1, NE_EXPR, e, si);
4022 /* In the case of NAME == 0 or NAME != 1, for TRUTH_OR_EXPR defining
4023 statement of NAME we can assert both operands of the TRUTH_OR_EXPR
4025 if (((comp_code == EQ_EXPR && integer_zerop (val))
4026 || (comp_code == NE_EXPR && integer_onep (val))))
4028 tree def_stmt = SSA_NAME_DEF_STMT (name);
4030 if (TREE_CODE (def_stmt) == GIMPLE_MODIFY_STMT
4031 && (TREE_CODE (GIMPLE_STMT_OPERAND (def_stmt, 1)) == TRUTH_OR_EXPR
4032 /* For BIT_IOR_EXPR only if NAME == 0 both operands have
4033 necessarily zero value. */
4034 || (comp_code == EQ_EXPR
4035 && (TREE_CODE (GIMPLE_STMT_OPERAND (def_stmt, 1))
4038 tree op0 = TREE_OPERAND (GIMPLE_STMT_OPERAND (def_stmt, 1), 0);
4039 tree op1 = TREE_OPERAND (GIMPLE_STMT_OPERAND (def_stmt, 1), 1);
4040 retval |= register_edge_assert_for_1 (op0, EQ_EXPR, e, si);
4041 retval |= register_edge_assert_for_1 (op1, EQ_EXPR, e, si);
4049 static bool find_assert_locations (basic_block bb);
4051 /* Determine whether the outgoing edges of BB should receive an
4052 ASSERT_EXPR for each of the operands of BB's LAST statement.
4053 The last statement of BB must be a COND_EXPR.
4055 If any of the sub-graphs rooted at BB have an interesting use of
4056 the predicate operands, an assert location node is added to the
4057 list of assertions for the corresponding operands. */
4060 find_conditional_asserts (basic_block bb, tree last)
4063 block_stmt_iterator bsi;
4069 need_assert = false;
4070 bsi = bsi_for_stmt (last);
4072 /* Look for uses of the operands in each of the sub-graphs
4073 rooted at BB. We need to check each of the outgoing edges
4074 separately, so that we know what kind of ASSERT_EXPR to
4076 FOR_EACH_EDGE (e, ei, bb->succs)
4081 /* Remove the COND_EXPR operands from the FOUND_IN_SUBGRAPH bitmap.
4082 Otherwise, when we finish traversing each of the sub-graphs, we
4083 won't know whether the variables were found in the sub-graphs or
4084 if they had been found in a block upstream from BB.
4086 This is actually a bad idea is some cases, particularly jump
4087 threading. Consider a CFG like the following:
4097 Assume that one or more operands in the conditional at the
4098 end of block 0 are used in a conditional in block 2, but not
4099 anywhere in block 1. In this case we will not insert any
4100 assert statements in block 1, which may cause us to miss
4101 opportunities to optimize, particularly for jump threading. */
4102 FOR_EACH_SSA_TREE_OPERAND (op, last, iter, SSA_OP_USE)
4103 RESET_BIT (found_in_subgraph, SSA_NAME_VERSION (op));
4105 /* Traverse the strictly dominated sub-graph rooted at E->DEST
4106 to determine if any of the operands in the conditional
4107 predicate are used. */
4108 need_assert |= find_assert_locations (e->dest);
4110 /* Register the necessary assertions for each operand in the
4111 conditional predicate. */
4112 FOR_EACH_SSA_TREE_OPERAND (op, last, iter, SSA_OP_USE)
4114 tree cond = COND_EXPR_COND (last);
4116 need_assert |= register_edge_assert_for (op, e, bsi,
4118 TREE_OPERAND (cond, 0),
4119 TREE_OPERAND (cond, 1));
4121 need_assert |= register_edge_assert_for (op, e, bsi, EQ_EXPR, op,
4126 /* Finally, indicate that we have found the operands in the
4128 FOR_EACH_SSA_TREE_OPERAND (op, last, iter, SSA_OP_USE)
4129 SET_BIT (found_in_subgraph, SSA_NAME_VERSION (op));
4134 /* Compare two case labels sorting first by the destination label uid
4135 and then by the case value. */
4138 compare_case_labels (const void *p1, const void *p2)
4140 const_tree const case1 = *(const_tree const*)p1;
4141 const_tree const case2 = *(const_tree const*)p2;
4142 unsigned int uid1 = DECL_UID (CASE_LABEL (case1));
4143 unsigned int uid2 = DECL_UID (CASE_LABEL (case2));
4147 else if (uid1 == uid2)
4149 /* Make sure the default label is first in a group. */
4150 if (!CASE_LOW (case1))
4152 else if (!CASE_LOW (case2))
4155 return tree_int_cst_compare (CASE_LOW (case1), CASE_LOW (case2));
4161 /* Determine whether the outgoing edges of BB should receive an
4162 ASSERT_EXPR for each of the operands of BB's LAST statement.
4163 The last statement of BB must be a SWITCH_EXPR.
4165 If any of the sub-graphs rooted at BB have an interesting use of
4166 the predicate operands, an assert location node is added to the
4167 list of assertions for the corresponding operands. */
4170 find_switch_asserts (basic_block bb, tree last)
4173 block_stmt_iterator bsi;
4176 tree vec = SWITCH_LABELS (last), vec2;
4177 size_t n = TREE_VEC_LENGTH (vec);
4180 need_assert = false;
4181 bsi = bsi_for_stmt (last);
4182 op = TREE_OPERAND (last, 0);
4183 if (TREE_CODE (op) != SSA_NAME)
4186 /* Build a vector of case labels sorted by destination label. */
4187 vec2 = make_tree_vec (n);
4188 for (idx = 0; idx < n; ++idx)
4189 TREE_VEC_ELT (vec2, idx) = TREE_VEC_ELT (vec, idx);
4190 qsort (&TREE_VEC_ELT (vec2, 0), n, sizeof (tree), compare_case_labels);
4192 for (idx = 0; idx < n; ++idx)
4195 tree cl = TREE_VEC_ELT (vec2, idx);
4197 min = CASE_LOW (cl);
4198 max = CASE_HIGH (cl);
4200 /* If there are multiple case labels with the same destination
4201 we need to combine them to a single value range for the edge. */
4203 && CASE_LABEL (cl) == CASE_LABEL (TREE_VEC_ELT (vec2, idx + 1)))
4205 /* Skip labels until the last of the group. */
4209 && CASE_LABEL (cl) == CASE_LABEL (TREE_VEC_ELT (vec2, idx)));
4212 /* Pick up the maximum of the case label range. */
4213 if (CASE_HIGH (TREE_VEC_ELT (vec2, idx)))
4214 max = CASE_HIGH (TREE_VEC_ELT (vec2, idx));
4216 max = CASE_LOW (TREE_VEC_ELT (vec2, idx));
4219 /* Nothing to do if the range includes the default label until we
4220 can register anti-ranges. */
4221 if (min == NULL_TREE)
4224 /* Find the edge to register the assert expr on. */
4225 e = find_edge (bb, label_to_block (CASE_LABEL (cl)));
4227 /* Remove the SWITCH_EXPR operand from the FOUND_IN_SUBGRAPH bitmap.
4228 Otherwise, when we finish traversing each of the sub-graphs, we
4229 won't know whether the variables were found in the sub-graphs or
4230 if they had been found in a block upstream from BB. */
4231 RESET_BIT (found_in_subgraph, SSA_NAME_VERSION (op));
4233 /* Traverse the strictly dominated sub-graph rooted at E->DEST
4234 to determine if any of the operands in the conditional
4235 predicate are used. */
4237 need_assert |= find_assert_locations (e->dest);
4239 /* Register the necessary assertions for the operand in the
4241 need_assert |= register_edge_assert_for (op, e, bsi,
4242 max ? GE_EXPR : EQ_EXPR,
4244 fold_convert (TREE_TYPE (op),
4248 need_assert |= register_edge_assert_for (op, e, bsi, LE_EXPR,
4250 fold_convert (TREE_TYPE (op),
4255 /* Finally, indicate that we have found the operand in the
4257 SET_BIT (found_in_subgraph, SSA_NAME_VERSION (op));
4263 /* Traverse all the statements in block BB looking for statements that
4264 may generate useful assertions for the SSA names in their operand.
4265 If a statement produces a useful assertion A for name N_i, then the
4266 list of assertions already generated for N_i is scanned to
4267 determine if A is actually needed.
4269 If N_i already had the assertion A at a location dominating the
4270 current location, then nothing needs to be done. Otherwise, the
4271 new location for A is recorded instead.
4273 1- For every statement S in BB, all the variables used by S are
4274 added to bitmap FOUND_IN_SUBGRAPH.
4276 2- If statement S uses an operand N in a way that exposes a known
4277 value range for N, then if N was not already generated by an
4278 ASSERT_EXPR, create a new assert location for N. For instance,
4279 if N is a pointer and the statement dereferences it, we can
4280 assume that N is not NULL.
4282 3- COND_EXPRs are a special case of #2. We can derive range
4283 information from the predicate but need to insert different
4284 ASSERT_EXPRs for each of the sub-graphs rooted at the
4285 conditional block. If the last statement of BB is a conditional
4286 expression of the form 'X op Y', then
4288 a) Remove X and Y from the set FOUND_IN_SUBGRAPH.
4290 b) If the conditional is the only entry point to the sub-graph
4291 corresponding to the THEN_CLAUSE, recurse into it. On
4292 return, if X and/or Y are marked in FOUND_IN_SUBGRAPH, then
4293 an ASSERT_EXPR is added for the corresponding variable.
4295 c) Repeat step (b) on the ELSE_CLAUSE.
4297 d) Mark X and Y in FOUND_IN_SUBGRAPH.
4306 In this case, an assertion on the THEN clause is useful to
4307 determine that 'a' is always 9 on that edge. However, an assertion
4308 on the ELSE clause would be unnecessary.
4310 4- If BB does not end in a conditional expression, then we recurse
4311 into BB's dominator children.
4313 At the end of the recursive traversal, every SSA name will have a
4314 list of locations where ASSERT_EXPRs should be added. When a new
4315 location for name N is found, it is registered by calling
4316 register_new_assert_for. That function keeps track of all the
4317 registered assertions to prevent adding unnecessary assertions.
4318 For instance, if a pointer P_4 is dereferenced more than once in a
4319 dominator tree, only the location dominating all the dereference of
4320 P_4 will receive an ASSERT_EXPR.
4322 If this function returns true, then it means that there are names
4323 for which we need to generate ASSERT_EXPRs. Those assertions are
4324 inserted by process_assert_insertions. */
4327 find_assert_locations (basic_block bb)
4329 block_stmt_iterator si;
4334 if (TEST_BIT (blocks_visited, bb->index))
4337 SET_BIT (blocks_visited, bb->index);
4339 need_assert = false;
4341 /* Traverse all PHI nodes in BB marking used operands. */
4342 for (phi = phi_nodes (bb); phi; phi = PHI_CHAIN (phi))
4344 use_operand_p arg_p;
4347 FOR_EACH_PHI_ARG (arg_p, phi, i, SSA_OP_USE)
4349 tree arg = USE_FROM_PTR (arg_p);
4350 if (TREE_CODE (arg) == SSA_NAME)
4352 gcc_assert (is_gimple_reg (PHI_RESULT (phi)));
4353 SET_BIT (found_in_subgraph, SSA_NAME_VERSION (arg));
4358 /* Traverse all the statements in BB marking used names and looking
4359 for statements that may infer assertions for their used operands. */
4361 for (si = bsi_start (bb); !bsi_end_p (si); bsi_next (&si))
4366 stmt = bsi_stmt (si);
4368 /* See if we can derive an assertion for any of STMT's operands. */
4369 FOR_EACH_SSA_TREE_OPERAND (op, stmt, i, SSA_OP_USE)
4372 enum tree_code comp_code;
4374 /* Mark OP in bitmap FOUND_IN_SUBGRAPH. If STMT is inside
4375 the sub-graph of a conditional block, when we return from
4376 this recursive walk, our parent will use the
4377 FOUND_IN_SUBGRAPH bitset to determine if one of the
4378 operands it was looking for was present in the sub-graph. */
4379 SET_BIT (found_in_subgraph, SSA_NAME_VERSION (op));
4381 /* If OP is used in such a way that we can infer a value
4382 range for it, and we don't find a previous assertion for
4383 it, create a new assertion location node for OP. */
4384 if (infer_value_range (stmt, op, &comp_code, &value))
4386 /* If we are able to infer a nonzero value range for OP,
4387 then walk backwards through the use-def chain to see if OP
4388 was set via a typecast.
4390 If so, then we can also infer a nonzero value range
4391 for the operand of the NOP_EXPR. */
4392 if (comp_code == NE_EXPR && integer_zerop (value))
4395 tree def_stmt = SSA_NAME_DEF_STMT (t);
4397 while (TREE_CODE (def_stmt) == GIMPLE_MODIFY_STMT
4399 (GIMPLE_STMT_OPERAND (def_stmt, 1)) == NOP_EXPR
4401 (TREE_OPERAND (GIMPLE_STMT_OPERAND (def_stmt, 1),
4404 (TREE_TYPE (TREE_OPERAND
4405 (GIMPLE_STMT_OPERAND (def_stmt,
4408 t = TREE_OPERAND (GIMPLE_STMT_OPERAND (def_stmt, 1), 0);
4409 def_stmt = SSA_NAME_DEF_STMT (t);
4411 /* Note we want to register the assert for the
4412 operand of the NOP_EXPR after SI, not after the
4414 if (! has_single_use (t))
4416 register_new_assert_for (t, t, comp_code, value,
4423 /* If OP is used only once, namely in this STMT, don't
4424 bother creating an ASSERT_EXPR for it. Such an
4425 ASSERT_EXPR would do nothing but increase compile time. */
4426 if (!has_single_use (op))
4428 register_new_assert_for (op, op, comp_code, value,
4435 /* Remember the last statement of the block. */
4439 /* If BB's last statement is a conditional expression
4440 involving integer operands, recurse into each of the sub-graphs
4441 rooted at BB to determine if we need to add ASSERT_EXPRs. */
4443 && TREE_CODE (last) == COND_EXPR
4444 && !fp_predicate (COND_EXPR_COND (last))
4445 && !ZERO_SSA_OPERANDS (last, SSA_OP_USE))
4446 need_assert |= find_conditional_asserts (bb, last);
4449 && TREE_CODE (last) == SWITCH_EXPR
4450 && !ZERO_SSA_OPERANDS (last, SSA_OP_USE))
4451 need_assert |= find_switch_asserts (bb, last);
4453 /* Recurse into the dominator children of BB. */
4454 for (son = first_dom_son (CDI_DOMINATORS, bb);
4456 son = next_dom_son (CDI_DOMINATORS, son))
4457 need_assert |= find_assert_locations (son);
4463 /* Create an ASSERT_EXPR for NAME and insert it in the location
4464 indicated by LOC. Return true if we made any edge insertions. */
4467 process_assert_insertions_for (tree name, assert_locus_t loc)
4469 /* Build the comparison expression NAME_i COMP_CODE VAL. */
4470 tree stmt, cond, assert_expr;
4474 cond = build2 (loc->comp_code, boolean_type_node, loc->expr, loc->val);
4475 assert_expr = build_assert_expr_for (cond, name);
4479 /* We have been asked to insert the assertion on an edge. This
4480 is used only by COND_EXPR and SWITCH_EXPR assertions. */
4481 #if defined ENABLE_CHECKING
4482 gcc_assert (TREE_CODE (bsi_stmt (loc->si)) == COND_EXPR
4483 || TREE_CODE (bsi_stmt (loc->si)) == SWITCH_EXPR);
4486 bsi_insert_on_edge (loc->e, assert_expr);
4490 /* Otherwise, we can insert right after LOC->SI iff the
4491 statement must not be the last statement in the block. */
4492 stmt = bsi_stmt (loc->si);
4493 if (!stmt_ends_bb_p (stmt))
4495 bsi_insert_after (&loc->si, assert_expr, BSI_SAME_STMT);
4499 /* If STMT must be the last statement in BB, we can only insert new
4500 assertions on the non-abnormal edge out of BB. Note that since
4501 STMT is not control flow, there may only be one non-abnormal edge
4503 FOR_EACH_EDGE (e, ei, loc->bb->succs)
4504 if (!(e->flags & EDGE_ABNORMAL))
4506 bsi_insert_on_edge (e, assert_expr);
4514 /* Process all the insertions registered for every name N_i registered
4515 in NEED_ASSERT_FOR. The list of assertions to be inserted are
4516 found in ASSERTS_FOR[i]. */
4519 process_assert_insertions (void)
4523 bool update_edges_p = false;
4524 int num_asserts = 0;
4526 if (dump_file && (dump_flags & TDF_DETAILS))
4527 dump_all_asserts (dump_file);
4529 EXECUTE_IF_SET_IN_BITMAP (need_assert_for, 0, i, bi)
4531 assert_locus_t loc = asserts_for[i];
4536 assert_locus_t next = loc->next;
4537 update_edges_p |= process_assert_insertions_for (ssa_name (i), loc);
4545 bsi_commit_edge_inserts ();
4547 if (dump_file && (dump_flags & TDF_STATS))
4548 fprintf (dump_file, "\nNumber of ASSERT_EXPR expressions inserted: %d\n\n",
4553 /* Traverse the flowgraph looking for conditional jumps to insert range
4554 expressions. These range expressions are meant to provide information
4555 to optimizations that need to reason in terms of value ranges. They
4556 will not be expanded into RTL. For instance, given:
4565 this pass will transform the code into:
4571 x = ASSERT_EXPR <x, x < y>
4576 y = ASSERT_EXPR <y, x <= y>
4580 The idea is that once copy and constant propagation have run, other
4581 optimizations will be able to determine what ranges of values can 'x'
4582 take in different paths of the code, simply by checking the reaching
4583 definition of 'x'. */
4586 insert_range_assertions (void)
4592 found_in_subgraph = sbitmap_alloc (num_ssa_names);
4593 sbitmap_zero (found_in_subgraph);
4595 blocks_visited = sbitmap_alloc (last_basic_block);
4596 sbitmap_zero (blocks_visited);
4598 need_assert_for = BITMAP_ALLOC (NULL);
4599 asserts_for = XCNEWVEC (assert_locus_t, num_ssa_names);
4601 calculate_dominance_info (CDI_DOMINATORS);
4603 update_ssa_p = false;
4604 FOR_EACH_EDGE (e, ei, ENTRY_BLOCK_PTR->succs)
4605 if (find_assert_locations (e->dest))
4606 update_ssa_p = true;
4610 process_assert_insertions ();
4611 update_ssa (TODO_update_ssa_no_phi);
4614 if (dump_file && (dump_flags & TDF_DETAILS))
4616 fprintf (dump_file, "\nSSA form after inserting ASSERT_EXPRs\n");
4617 dump_function_to_file (current_function_decl, dump_file, dump_flags);
4620 sbitmap_free (found_in_subgraph);
4622 BITMAP_FREE (need_assert_for);
4625 /* Checks one ARRAY_REF in REF, located at LOCUS. Ignores flexible arrays
4626 and "struct" hacks. If VRP can determine that the
4627 array subscript is a constant, check if it is outside valid
4628 range. If the array subscript is a RANGE, warn if it is
4629 non-overlapping with valid range.
4630 IGNORE_OFF_BY_ONE is true if the ARRAY_REF is inside a ADDR_EXPR. */
4633 check_array_ref (tree ref, location_t* locus, bool ignore_off_by_one)
4635 value_range_t* vr = NULL;
4636 tree low_sub, up_sub;
4637 tree low_bound, up_bound = array_ref_up_bound (ref);
4639 low_sub = up_sub = TREE_OPERAND (ref, 1);
4641 if (!up_bound || TREE_NO_WARNING (ref)
4642 || TREE_CODE (up_bound) != INTEGER_CST
4643 /* Can not check flexible arrays. */
4644 || (TYPE_SIZE (TREE_TYPE (ref)) == NULL_TREE
4645 && TYPE_DOMAIN (TREE_TYPE (ref)) != NULL_TREE
4646 && TYPE_MAX_VALUE (TYPE_DOMAIN (TREE_TYPE (ref))) == NULL_TREE)
4647 /* Accesses after the end of arrays of size 0 (gcc
4648 extension) and 1 are likely intentional ("struct
4650 || compare_tree_int (up_bound, 1) <= 0)
4653 low_bound = array_ref_low_bound (ref);
4655 if (TREE_CODE (low_sub) == SSA_NAME)
4657 vr = get_value_range (low_sub);
4658 if (vr->type == VR_RANGE || vr->type == VR_ANTI_RANGE)
4660 low_sub = vr->type == VR_RANGE ? vr->max : vr->min;
4661 up_sub = vr->type == VR_RANGE ? vr->min : vr->max;
4665 if (vr && vr->type == VR_ANTI_RANGE)
4667 if (TREE_CODE (up_sub) == INTEGER_CST
4668 && tree_int_cst_lt (up_bound, up_sub)
4669 && TREE_CODE (low_sub) == INTEGER_CST
4670 && tree_int_cst_lt (low_sub, low_bound))
4672 warning (OPT_Warray_bounds,
4673 "%Harray subscript is outside array bounds", locus);
4674 TREE_NO_WARNING (ref) = 1;
4677 else if (TREE_CODE (up_sub) == INTEGER_CST
4678 && tree_int_cst_lt (up_bound, up_sub)
4679 && !tree_int_cst_equal (up_bound, up_sub)
4680 && (!ignore_off_by_one
4681 || !tree_int_cst_equal (int_const_binop (PLUS_EXPR,
4687 warning (OPT_Warray_bounds, "%Harray subscript is above array bounds",
4689 TREE_NO_WARNING (ref) = 1;
4691 else if (TREE_CODE (low_sub) == INTEGER_CST
4692 && tree_int_cst_lt (low_sub, low_bound))
4694 warning (OPT_Warray_bounds, "%Harray subscript is below array bounds",
4696 TREE_NO_WARNING (ref) = 1;
4700 /* Searches if the expr T, located at LOCATION computes
4701 address of an ARRAY_REF, and call check_array_ref on it. */
4704 search_for_addr_array(tree t, location_t* location)
4706 while (TREE_CODE (t) == SSA_NAME)
4708 t = SSA_NAME_DEF_STMT (t);
4709 if (TREE_CODE (t) != GIMPLE_MODIFY_STMT)
4711 t = GIMPLE_STMT_OPERAND (t, 1);
4715 /* We are only interested in addresses of ARRAY_REF's. */
4716 if (TREE_CODE (t) != ADDR_EXPR)
4719 /* Check each ARRAY_REFs in the reference chain. */
4722 if (TREE_CODE (t) == ARRAY_REF)
4723 check_array_ref (t, location, true /*ignore_off_by_one*/);
4725 t = TREE_OPERAND(t,0);
4727 while (handled_component_p (t));
4730 /* walk_tree() callback that checks if *TP is
4731 an ARRAY_REF inside an ADDR_EXPR (in which an array
4732 subscript one outside the valid range is allowed). Call
4733 check_array_ref for each ARRAY_REF found. The location is
4737 check_array_bounds (tree *tp, int *walk_subtree, void *data)
4740 tree stmt = (tree)data;
4741 location_t *location = EXPR_LOCUS (stmt);
4743 if (!EXPR_HAS_LOCATION (stmt))
4745 *walk_subtree = FALSE;
4749 *walk_subtree = TRUE;
4751 if (TREE_CODE (t) == ARRAY_REF)
4752 check_array_ref (t, location, false /*ignore_off_by_one*/);
4754 if (TREE_CODE (t) == INDIRECT_REF
4755 || (TREE_CODE (t) == RETURN_EXPR && TREE_OPERAND (t, 0)))
4756 search_for_addr_array (TREE_OPERAND (t, 0), location);
4757 else if (TREE_CODE (t) == CALL_EXPR)
4760 call_expr_arg_iterator iter;
4762 FOR_EACH_CALL_EXPR_ARG (arg, iter, t)
4763 search_for_addr_array (arg, location);
4766 if (TREE_CODE (t) == ADDR_EXPR)
4767 *walk_subtree = FALSE;
4772 /* Walk over all statements of all reachable BBs and call check_array_bounds
4776 check_all_array_refs (void)
4779 block_stmt_iterator si;
4783 /* Skip bb's that are clearly unreachable. */
4784 if (single_pred_p (bb))
4786 basic_block pred_bb = EDGE_PRED (bb, 0)->src;
4787 tree ls = NULL_TREE;
4789 if (!bsi_end_p (bsi_last (pred_bb)))
4790 ls = bsi_stmt (bsi_last (pred_bb));
4792 if (ls && TREE_CODE (ls) == COND_EXPR
4793 && ((COND_EXPR_COND (ls) == boolean_false_node
4794 && (EDGE_PRED (bb, 0)->flags & EDGE_TRUE_VALUE))
4795 || (COND_EXPR_COND (ls) == boolean_true_node
4796 && (EDGE_PRED (bb, 0)->flags & EDGE_FALSE_VALUE))))
4799 for (si = bsi_start (bb); !bsi_end_p (si); bsi_next (&si))
4800 walk_tree (bsi_stmt_ptr (si), check_array_bounds,
4801 bsi_stmt (si), NULL);
4805 /* Convert range assertion expressions into the implied copies and
4806 copy propagate away the copies. Doing the trivial copy propagation
4807 here avoids the need to run the full copy propagation pass after
4810 FIXME, this will eventually lead to copy propagation removing the
4811 names that had useful range information attached to them. For
4812 instance, if we had the assertion N_i = ASSERT_EXPR <N_j, N_j > 3>,
4813 then N_i will have the range [3, +INF].
4815 However, by converting the assertion into the implied copy
4816 operation N_i = N_j, we will then copy-propagate N_j into the uses
4817 of N_i and lose the range information. We may want to hold on to
4818 ASSERT_EXPRs a little while longer as the ranges could be used in
4819 things like jump threading.
4821 The problem with keeping ASSERT_EXPRs around is that passes after
4822 VRP need to handle them appropriately.
4824 Another approach would be to make the range information a first
4825 class property of the SSA_NAME so that it can be queried from
4826 any pass. This is made somewhat more complex by the need for
4827 multiple ranges to be associated with one SSA_NAME. */
4830 remove_range_assertions (void)
4833 block_stmt_iterator si;
4835 /* Note that the BSI iterator bump happens at the bottom of the
4836 loop and no bump is necessary if we're removing the statement
4837 referenced by the current BSI. */
4839 for (si = bsi_start (bb); !bsi_end_p (si);)
4841 tree stmt = bsi_stmt (si);
4844 if (TREE_CODE (stmt) == GIMPLE_MODIFY_STMT
4845 && TREE_CODE (GIMPLE_STMT_OPERAND (stmt, 1)) == ASSERT_EXPR)
4847 tree rhs = GIMPLE_STMT_OPERAND (stmt, 1), var;
4848 tree cond = fold (ASSERT_EXPR_COND (rhs));
4849 use_operand_p use_p;
4850 imm_use_iterator iter;
4852 gcc_assert (cond != boolean_false_node);
4854 /* Propagate the RHS into every use of the LHS. */
4855 var = ASSERT_EXPR_VAR (rhs);
4856 FOR_EACH_IMM_USE_STMT (use_stmt, iter,
4857 GIMPLE_STMT_OPERAND (stmt, 0))
4858 FOR_EACH_IMM_USE_ON_STMT (use_p, iter)
4860 SET_USE (use_p, var);
4861 gcc_assert (TREE_CODE (var) == SSA_NAME);
4864 /* And finally, remove the copy, it is not needed. */
4865 bsi_remove (&si, true);
4866 release_defs (stmt);
4872 sbitmap_free (blocks_visited);
4876 /* Return true if STMT is interesting for VRP. */
4879 stmt_interesting_for_vrp (tree stmt)
4881 if (TREE_CODE (stmt) == PHI_NODE
4882 && is_gimple_reg (PHI_RESULT (stmt))
4883 && (INTEGRAL_TYPE_P (TREE_TYPE (PHI_RESULT (stmt)))
4884 || POINTER_TYPE_P (TREE_TYPE (PHI_RESULT (stmt)))))
4886 else if (TREE_CODE (stmt) == GIMPLE_MODIFY_STMT)
4888 tree lhs = GIMPLE_STMT_OPERAND (stmt, 0);
4889 tree rhs = GIMPLE_STMT_OPERAND (stmt, 1);
4891 /* In general, assignments with virtual operands are not useful
4892 for deriving ranges, with the obvious exception of calls to
4893 builtin functions. */
4894 if (TREE_CODE (lhs) == SSA_NAME
4895 && (INTEGRAL_TYPE_P (TREE_TYPE (lhs))
4896 || POINTER_TYPE_P (TREE_TYPE (lhs)))
4897 && ((TREE_CODE (rhs) == CALL_EXPR
4898 && TREE_CODE (CALL_EXPR_FN (rhs)) == ADDR_EXPR
4899 && DECL_P (TREE_OPERAND (CALL_EXPR_FN (rhs), 0))
4900 && DECL_IS_BUILTIN (TREE_OPERAND (CALL_EXPR_FN (rhs), 0)))
4901 || ZERO_SSA_OPERANDS (stmt, SSA_OP_ALL_VIRTUALS)))
4904 else if (TREE_CODE (stmt) == COND_EXPR || TREE_CODE (stmt) == SWITCH_EXPR)
4911 /* Initialize local data structures for VRP. */
4914 vrp_initialize (void)
4918 vr_value = XCNEWVEC (value_range_t *, num_ssa_names);
4919 vr_phi_edge_counts = XCNEWVEC (int, num_ssa_names);
4923 block_stmt_iterator si;
4926 for (phi = phi_nodes (bb); phi; phi = PHI_CHAIN (phi))
4928 if (!stmt_interesting_for_vrp (phi))
4930 tree lhs = PHI_RESULT (phi);
4931 set_value_range_to_varying (get_value_range (lhs));
4932 DONT_SIMULATE_AGAIN (phi) = true;
4935 DONT_SIMULATE_AGAIN (phi) = false;
4938 for (si = bsi_start (bb); !bsi_end_p (si); bsi_next (&si))
4940 tree stmt = bsi_stmt (si);
4942 if (!stmt_interesting_for_vrp (stmt))
4946 FOR_EACH_SSA_TREE_OPERAND (def, stmt, i, SSA_OP_DEF)
4947 set_value_range_to_varying (get_value_range (def));
4948 DONT_SIMULATE_AGAIN (stmt) = true;
4952 DONT_SIMULATE_AGAIN (stmt) = false;
4959 /* Visit assignment STMT. If it produces an interesting range, record
4960 the SSA name in *OUTPUT_P. */
4962 static enum ssa_prop_result
4963 vrp_visit_assignment (tree stmt, tree *output_p)
4968 lhs = GIMPLE_STMT_OPERAND (stmt, 0);
4969 rhs = GIMPLE_STMT_OPERAND (stmt, 1);
4971 /* We only keep track of ranges in integral and pointer types. */
4972 if (TREE_CODE (lhs) == SSA_NAME
4973 && ((INTEGRAL_TYPE_P (TREE_TYPE (lhs))
4974 /* It is valid to have NULL MIN/MAX values on a type. See
4975 build_range_type. */
4976 && TYPE_MIN_VALUE (TREE_TYPE (lhs))
4977 && TYPE_MAX_VALUE (TREE_TYPE (lhs)))
4978 || POINTER_TYPE_P (TREE_TYPE (lhs))))
4981 value_range_t new_vr = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
4983 extract_range_from_expr (&new_vr, rhs);
4985 /* If STMT is inside a loop, we may be able to know something
4986 else about the range of LHS by examining scalar evolution
4988 if (current_loops && (l = loop_containing_stmt (stmt)))
4989 adjust_range_with_scev (&new_vr, l, stmt, lhs);
4991 if (update_value_range (lhs, &new_vr))
4995 if (dump_file && (dump_flags & TDF_DETAILS))
4997 fprintf (dump_file, "Found new range for ");
4998 print_generic_expr (dump_file, lhs, 0);
4999 fprintf (dump_file, ": ");
5000 dump_value_range (dump_file, &new_vr);
5001 fprintf (dump_file, "\n\n");
5004 if (new_vr.type == VR_VARYING)
5005 return SSA_PROP_VARYING;
5007 return SSA_PROP_INTERESTING;
5010 return SSA_PROP_NOT_INTERESTING;
5013 /* Every other statement produces no useful ranges. */
5014 FOR_EACH_SSA_TREE_OPERAND (def, stmt, iter, SSA_OP_DEF)
5015 set_value_range_to_varying (get_value_range (def));
5017 return SSA_PROP_VARYING;
5020 /* Helper that gets the value range of the SSA_NAME with version I
5021 or a symbolic range containing the SSA_NAME only if the value range
5022 is varying or undefined. */
5024 static inline value_range_t
5025 get_vr_for_comparison (int i)
5027 value_range_t vr = *(vr_value[i]);
5029 /* If name N_i does not have a valid range, use N_i as its own
5030 range. This allows us to compare against names that may
5031 have N_i in their ranges. */
5032 if (vr.type == VR_VARYING || vr.type == VR_UNDEFINED)
5035 vr.min = ssa_name (i);
5036 vr.max = ssa_name (i);
5042 /* Compare all the value ranges for names equivalent to VAR with VAL
5043 using comparison code COMP. Return the same value returned by
5044 compare_range_with_value, including the setting of
5045 *STRICT_OVERFLOW_P. */
5048 compare_name_with_value (enum tree_code comp, tree var, tree val,
5049 bool *strict_overflow_p)
5055 int used_strict_overflow;
5057 value_range_t equiv_vr;
5059 /* Get the set of equivalences for VAR. */
5060 e = get_value_range (var)->equiv;
5062 /* Start at -1. Set it to 0 if we do a comparison without relying
5063 on overflow, or 1 if all comparisons rely on overflow. */
5064 used_strict_overflow = -1;
5066 /* Compare vars' value range with val. */
5067 equiv_vr = get_vr_for_comparison (SSA_NAME_VERSION (var));
5069 retval = compare_range_with_value (comp, &equiv_vr, val, &sop);
5071 used_strict_overflow = sop ? 1 : 0;
5073 /* If the equiv set is empty we have done all work we need to do. */
5077 && used_strict_overflow > 0)
5078 *strict_overflow_p = true;
5082 EXECUTE_IF_SET_IN_BITMAP (e, 0, i, bi)
5084 equiv_vr = get_vr_for_comparison (i);
5086 t = compare_range_with_value (comp, &equiv_vr, val, &sop);
5089 /* If we get different answers from different members
5090 of the equivalence set this check must be in a dead
5091 code region. Folding it to a trap representation
5092 would be correct here. For now just return don't-know. */
5102 used_strict_overflow = 0;
5103 else if (used_strict_overflow < 0)
5104 used_strict_overflow = 1;
5109 && used_strict_overflow > 0)
5110 *strict_overflow_p = true;
5116 /* Given a comparison code COMP and names N1 and N2, compare all the
5117 ranges equivalent to N1 against all the ranges equivalent to N2
5118 to determine the value of N1 COMP N2. Return the same value
5119 returned by compare_ranges. Set *STRICT_OVERFLOW_P to indicate
5120 whether we relied on an overflow infinity in the comparison. */
5124 compare_names (enum tree_code comp, tree n1, tree n2,
5125 bool *strict_overflow_p)
5129 bitmap_iterator bi1, bi2;
5131 int used_strict_overflow;
5132 static bitmap_obstack *s_obstack = NULL;
5133 static bitmap s_e1 = NULL, s_e2 = NULL;
5135 /* Compare the ranges of every name equivalent to N1 against the
5136 ranges of every name equivalent to N2. */
5137 e1 = get_value_range (n1)->equiv;
5138 e2 = get_value_range (n2)->equiv;
5140 /* Use the fake bitmaps if e1 or e2 are not available. */
5141 if (s_obstack == NULL)
5143 s_obstack = XNEW (bitmap_obstack);
5144 bitmap_obstack_initialize (s_obstack);
5145 s_e1 = BITMAP_ALLOC (s_obstack);
5146 s_e2 = BITMAP_ALLOC (s_obstack);
5153 /* Add N1 and N2 to their own set of equivalences to avoid
5154 duplicating the body of the loop just to check N1 and N2
5156 bitmap_set_bit (e1, SSA_NAME_VERSION (n1));
5157 bitmap_set_bit (e2, SSA_NAME_VERSION (n2));
5159 /* If the equivalence sets have a common intersection, then the two
5160 names can be compared without checking their ranges. */
5161 if (bitmap_intersect_p (e1, e2))
5163 bitmap_clear_bit (e1, SSA_NAME_VERSION (n1));
5164 bitmap_clear_bit (e2, SSA_NAME_VERSION (n2));
5166 return (comp == EQ_EXPR || comp == GE_EXPR || comp == LE_EXPR)
5168 : boolean_false_node;
5171 /* Start at -1. Set it to 0 if we do a comparison without relying
5172 on overflow, or 1 if all comparisons rely on overflow. */
5173 used_strict_overflow = -1;
5175 /* Otherwise, compare all the equivalent ranges. First, add N1 and
5176 N2 to their own set of equivalences to avoid duplicating the body
5177 of the loop just to check N1 and N2 ranges. */
5178 EXECUTE_IF_SET_IN_BITMAP (e1, 0, i1, bi1)
5180 value_range_t vr1 = get_vr_for_comparison (i1);
5182 t = retval = NULL_TREE;
5183 EXECUTE_IF_SET_IN_BITMAP (e2, 0, i2, bi2)
5187 value_range_t vr2 = get_vr_for_comparison (i2);
5189 t = compare_ranges (comp, &vr1, &vr2, &sop);
5192 /* If we get different answers from different members
5193 of the equivalence set this check must be in a dead
5194 code region. Folding it to a trap representation
5195 would be correct here. For now just return don't-know. */
5199 bitmap_clear_bit (e1, SSA_NAME_VERSION (n1));
5200 bitmap_clear_bit (e2, SSA_NAME_VERSION (n2));
5206 used_strict_overflow = 0;
5207 else if (used_strict_overflow < 0)
5208 used_strict_overflow = 1;
5214 bitmap_clear_bit (e1, SSA_NAME_VERSION (n1));
5215 bitmap_clear_bit (e2, SSA_NAME_VERSION (n2));
5216 if (used_strict_overflow > 0)
5217 *strict_overflow_p = true;
5222 /* None of the equivalent ranges are useful in computing this
5224 bitmap_clear_bit (e1, SSA_NAME_VERSION (n1));
5225 bitmap_clear_bit (e2, SSA_NAME_VERSION (n2));
5229 /* Helper function for vrp_evaluate_conditional_warnv. */
5232 vrp_evaluate_conditional_warnv_with_ops (enum tree_code code, tree op0,
5233 tree op1, bool use_equiv_p,
5234 bool *strict_overflow_p)
5236 /* We only deal with integral and pointer types. */
5237 if (!INTEGRAL_TYPE_P (TREE_TYPE (op0))
5238 && !POINTER_TYPE_P (TREE_TYPE (op0)))
5243 if (TREE_CODE (op0) == SSA_NAME && TREE_CODE (op1) == SSA_NAME)
5244 return compare_names (code, op0, op1,
5246 else if (TREE_CODE (op0) == SSA_NAME)
5247 return compare_name_with_value (code, op0, op1,
5249 else if (TREE_CODE (op1) == SSA_NAME)
5250 return (compare_name_with_value
5251 (swap_tree_comparison (code), op1, op0,
5252 strict_overflow_p));
5256 value_range_t *vr0, *vr1;
5258 vr0 = (TREE_CODE (op0) == SSA_NAME) ? get_value_range (op0) : NULL;
5259 vr1 = (TREE_CODE (op1) == SSA_NAME) ? get_value_range (op1) : NULL;
5262 return compare_ranges (code, vr0, vr1,
5264 else if (vr0 && vr1 == NULL)
5265 return compare_range_with_value (code, vr0, op1,
5267 else if (vr0 == NULL && vr1)
5268 return (compare_range_with_value
5269 (swap_tree_comparison (code), vr1, op0,
5270 strict_overflow_p));
5275 /* Given a conditional predicate COND, try to determine if COND yields
5276 true or false based on the value ranges of its operands. Return
5277 BOOLEAN_TRUE_NODE if the conditional always evaluates to true,
5278 BOOLEAN_FALSE_NODE if the conditional always evaluates to false, and,
5279 NULL if the conditional cannot be evaluated at compile time.
5281 If USE_EQUIV_P is true, the ranges of all the names equivalent with
5282 the operands in COND are used when trying to compute its value.
5283 This is only used during final substitution. During propagation,
5284 we only check the range of each variable and not its equivalents.
5286 Set *STRICT_OVERFLOW_P to indicate whether we relied on an overflow
5287 infinity to produce the result. */
5290 vrp_evaluate_conditional_warnv (tree cond, bool use_equiv_p,
5291 bool *strict_overflow_p)
5293 gcc_assert (TREE_CODE (cond) == SSA_NAME
5294 || TREE_CODE_CLASS (TREE_CODE (cond)) == tcc_comparison);
5296 if (TREE_CODE (cond) == SSA_NAME)
5302 retval = compare_name_with_value (NE_EXPR, cond, boolean_false_node,
5306 value_range_t *vr = get_value_range (cond);
5307 retval = compare_range_with_value (NE_EXPR, vr, boolean_false_node,
5311 /* If COND has a known boolean range, return it. */
5315 /* Otherwise, if COND has a symbolic range of exactly one value,
5317 vr = get_value_range (cond);
5318 if (vr->type == VR_RANGE && vr->min == vr->max)
5322 return vrp_evaluate_conditional_warnv_with_ops (TREE_CODE (cond),
5323 TREE_OPERAND (cond, 0),
5324 TREE_OPERAND (cond, 1),
5328 /* Anything else cannot be computed statically. */
5332 /* Given COND within STMT, try to simplify it based on value range
5333 information. Return NULL if the conditional can not be evaluated.
5334 The ranges of all the names equivalent with the operands in COND
5335 will be used when trying to compute the value. If the result is
5336 based on undefined signed overflow, issue a warning if
5340 vrp_evaluate_conditional (tree cond, tree stmt)
5346 ret = vrp_evaluate_conditional_warnv (cond, true, &sop);
5350 enum warn_strict_overflow_code wc;
5351 const char* warnmsg;
5353 if (is_gimple_min_invariant (ret))
5355 wc = WARN_STRICT_OVERFLOW_CONDITIONAL;
5356 warnmsg = G_("assuming signed overflow does not occur when "
5357 "simplifying conditional to constant");
5361 wc = WARN_STRICT_OVERFLOW_COMPARISON;
5362 warnmsg = G_("assuming signed overflow does not occur when "
5363 "simplifying conditional");
5366 if (issue_strict_overflow_warning (wc))
5370 if (!EXPR_HAS_LOCATION (stmt))
5371 locus = input_location;
5373 locus = EXPR_LOCATION (stmt);
5374 warning (OPT_Wstrict_overflow, "%H%s", &locus, warnmsg);
5378 if (warn_type_limits
5380 && TREE_CODE_CLASS (TREE_CODE (cond)) == tcc_comparison
5381 && TREE_CODE (TREE_OPERAND (cond, 0)) == SSA_NAME)
5383 /* If the comparison is being folded and the operand on the LHS
5384 is being compared against a constant value that is outside of
5385 the natural range of OP0's type, then the predicate will
5386 always fold regardless of the value of OP0. If -Wtype-limits
5387 was specified, emit a warning. */
5388 const char *warnmsg = NULL;
5389 tree op0 = TREE_OPERAND (cond, 0);
5390 tree op1 = TREE_OPERAND (cond, 1);
5391 tree type = TREE_TYPE (op0);
5392 value_range_t *vr0 = get_value_range (op0);
5394 if (vr0->type != VR_VARYING
5395 && INTEGRAL_TYPE_P (type)
5396 && vrp_val_is_min (vr0->min)
5397 && vrp_val_is_max (vr0->max)
5398 && is_gimple_min_invariant (op1))
5400 if (integer_zerop (ret))
5401 warnmsg = G_("comparison always false due to limited range of "
5404 warnmsg = G_("comparison always true due to limited range of "
5412 if (!EXPR_HAS_LOCATION (stmt))
5413 locus = input_location;
5415 locus = EXPR_LOCATION (stmt);
5417 warning (OPT_Wtype_limits, "%H%s", &locus, warnmsg);
5425 /* Visit conditional statement STMT. If we can determine which edge
5426 will be taken out of STMT's basic block, record it in
5427 *TAKEN_EDGE_P and return SSA_PROP_INTERESTING. Otherwise, return
5428 SSA_PROP_VARYING. */
5430 static enum ssa_prop_result
5431 vrp_visit_cond_stmt (tree stmt, edge *taken_edge_p)
5436 *taken_edge_p = NULL;
5437 cond = COND_EXPR_COND (stmt);
5439 if (dump_file && (dump_flags & TDF_DETAILS))
5444 fprintf (dump_file, "\nVisiting conditional with predicate: ");
5445 print_generic_expr (dump_file, cond, 0);
5446 fprintf (dump_file, "\nWith known ranges\n");
5448 FOR_EACH_SSA_TREE_OPERAND (use, stmt, i, SSA_OP_USE)
5450 fprintf (dump_file, "\t");
5451 print_generic_expr (dump_file, use, 0);
5452 fprintf (dump_file, ": ");
5453 dump_value_range (dump_file, vr_value[SSA_NAME_VERSION (use)]);
5456 fprintf (dump_file, "\n");
5459 /* Compute the value of the predicate COND by checking the known
5460 ranges of each of its operands.
5462 Note that we cannot evaluate all the equivalent ranges here
5463 because those ranges may not yet be final and with the current
5464 propagation strategy, we cannot determine when the value ranges
5465 of the names in the equivalence set have changed.
5467 For instance, given the following code fragment
5471 i_14 = ASSERT_EXPR <i_5, i_5 != 0>
5475 Assume that on the first visit to i_14, i_5 has the temporary
5476 range [8, 8] because the second argument to the PHI function is
5477 not yet executable. We derive the range ~[0, 0] for i_14 and the
5478 equivalence set { i_5 }. So, when we visit 'if (i_14 == 1)' for
5479 the first time, since i_14 is equivalent to the range [8, 8], we
5480 determine that the predicate is always false.
5482 On the next round of propagation, i_13 is determined to be
5483 VARYING, which causes i_5 to drop down to VARYING. So, another
5484 visit to i_14 is scheduled. In this second visit, we compute the
5485 exact same range and equivalence set for i_14, namely ~[0, 0] and
5486 { i_5 }. But we did not have the previous range for i_5
5487 registered, so vrp_visit_assignment thinks that the range for
5488 i_14 has not changed. Therefore, the predicate 'if (i_14 == 1)'
5489 is not visited again, which stops propagation from visiting
5490 statements in the THEN clause of that if().
5492 To properly fix this we would need to keep the previous range
5493 value for the names in the equivalence set. This way we would've
5494 discovered that from one visit to the other i_5 changed from
5495 range [8, 8] to VR_VARYING.
5497 However, fixing this apparent limitation may not be worth the
5498 additional checking. Testing on several code bases (GCC, DLV,
5499 MICO, TRAMP3D and SPEC2000) showed that doing this results in
5500 4 more predicates folded in SPEC. */
5502 val = vrp_evaluate_conditional_warnv (cond, false, &sop);
5506 *taken_edge_p = find_taken_edge (bb_for_stmt (stmt), val);
5509 if (dump_file && (dump_flags & TDF_DETAILS))
5511 "\nIgnoring predicate evaluation because "
5512 "it assumes that signed overflow is undefined");
5517 if (dump_file && (dump_flags & TDF_DETAILS))
5519 fprintf (dump_file, "\nPredicate evaluates to: ");
5520 if (val == NULL_TREE)
5521 fprintf (dump_file, "DON'T KNOW\n");
5523 print_generic_stmt (dump_file, val, 0);
5526 return (*taken_edge_p) ? SSA_PROP_INTERESTING : SSA_PROP_VARYING;
5529 /* Searches the case label vector VEC for the index *IDX of the CASE_LABEL
5530 that includes the value VAL. The search is restricted to the range
5531 [START_IDX, n - 2] where n is the size of VEC (n - 1 is the default label).
5533 If there is a CASE_LABEL for VAL, its index is placed in IDX and true is
5536 If there is no CASE_LABEL for VAL and the is one that is larger than VAL,
5537 it is placed in IDX and false is returned.
5539 If VAL is larger than any CASE_LABEL, n - 1 is placed on IDX and false is
5543 find_case_label_index (tree vec, size_t start_idx, tree val, size_t *idx)
5545 size_t n = TREE_VEC_LENGTH (vec);
5548 /* Find case label for minimum of the value range or the next one.
5549 At each iteration we are searching in [low, high - 1]. */
5551 for (low = start_idx, high = n - 1; high != low; )
5555 /* Note that i != high, so we never ask for n - 1. */
5556 size_t i = (high + low) / 2;
5557 t = TREE_VEC_ELT (vec, i);
5559 /* Cache the result of comparing CASE_LOW and val. */
5560 cmp = tree_int_cst_compare (CASE_LOW (t), val);
5564 /* Ranges cannot be empty. */
5573 if (CASE_HIGH (t) != NULL
5574 && tree_int_cst_compare (CASE_HIGH (t), val) >= 0)
5586 /* Searches the case label vector VEC for the range of CASE_LABELs that is used
5587 for values between MIN and MAX. The first index is placed in MIN_IDX. The
5588 last index is placed in MAX_IDX. If the range of CASE_LABELs is empty
5589 then MAX_IDX < MIN_IDX.
5590 Returns true if the default label is not needed. */
5593 find_case_label_range (tree vec, tree min, tree max, size_t *min_idx, size_t *max_idx)
5596 bool min_take_default = !find_case_label_index (vec, 0, min, &i);
5597 bool max_take_default = !find_case_label_index (vec, i, max, &j);
5601 && max_take_default)
5603 /* Only the default case label reached.
5604 Return an empty range. */
5611 bool take_default = min_take_default || max_take_default;
5615 if (max_take_default)
5618 /* If the case label range is continuous, we do not need
5619 the default case label. Verify that. */
5620 high = CASE_LOW (TREE_VEC_ELT (vec, i));
5621 if (CASE_HIGH (TREE_VEC_ELT (vec, i)))
5622 high = CASE_HIGH (TREE_VEC_ELT (vec, i));
5623 for (k = i + 1; k <= j; ++k)
5625 low = CASE_LOW (TREE_VEC_ELT (vec, k));
5626 if (!integer_onep (int_const_binop (MINUS_EXPR, low, high, 0)))
5628 take_default = true;
5632 if (CASE_HIGH (TREE_VEC_ELT (vec, k)))
5633 high = CASE_HIGH (TREE_VEC_ELT (vec, k));
5638 return !take_default;
5642 /* Visit switch statement STMT. If we can determine which edge
5643 will be taken out of STMT's basic block, record it in
5644 *TAKEN_EDGE_P and return SSA_PROP_INTERESTING. Otherwise, return
5645 SSA_PROP_VARYING. */
5647 static enum ssa_prop_result
5648 vrp_visit_switch_stmt (tree stmt, edge *taken_edge_p)
5652 size_t i = 0, j = 0, n;
5656 *taken_edge_p = NULL;
5657 op = TREE_OPERAND (stmt, 0);
5658 if (TREE_CODE (op) != SSA_NAME)
5659 return SSA_PROP_VARYING;
5661 vr = get_value_range (op);
5662 if (dump_file && (dump_flags & TDF_DETAILS))
5664 fprintf (dump_file, "\nVisiting switch expression with operand ");
5665 print_generic_expr (dump_file, op, 0);
5666 fprintf (dump_file, " with known range ");
5667 dump_value_range (dump_file, vr);
5668 fprintf (dump_file, "\n");
5671 if (vr->type != VR_RANGE
5672 || symbolic_range_p (vr))
5673 return SSA_PROP_VARYING;
5675 /* Find the single edge that is taken from the switch expression. */
5676 vec = SWITCH_LABELS (stmt);
5677 n = TREE_VEC_LENGTH (vec);
5679 take_default = !find_case_label_range (vec, vr->min, vr->max, &i, &j);
5681 /* Check if the range spans no CASE_LABEL. If so, we only reach the default
5685 gcc_assert (take_default);
5686 val = TREE_VEC_ELT (vec, n - 1);
5690 /* Check if labels with index i to j and maybe the default label
5691 are all reaching the same label. */
5693 val = TREE_VEC_ELT (vec, i);
5695 && CASE_LABEL (TREE_VEC_ELT (vec, n - 1)) != CASE_LABEL (val))
5697 if (dump_file && (dump_flags & TDF_DETAILS))
5698 fprintf (dump_file, " not a single destination for this "
5700 return SSA_PROP_VARYING;
5702 for (++i; i <= j; ++i)
5704 if (CASE_LABEL (TREE_VEC_ELT (vec, i)) != CASE_LABEL (val))
5706 if (dump_file && (dump_flags & TDF_DETAILS))
5707 fprintf (dump_file, " not a single destination for this "
5709 return SSA_PROP_VARYING;
5714 *taken_edge_p = find_edge (bb_for_stmt (stmt),
5715 label_to_block (CASE_LABEL (val)));
5717 if (dump_file && (dump_flags & TDF_DETAILS))
5719 fprintf (dump_file, " will take edge to ");
5720 print_generic_stmt (dump_file, CASE_LABEL (val), 0);
5723 return SSA_PROP_INTERESTING;
5727 /* Evaluate statement STMT. If the statement produces a useful range,
5728 return SSA_PROP_INTERESTING and record the SSA name with the
5729 interesting range into *OUTPUT_P.
5731 If STMT is a conditional branch and we can determine its truth
5732 value, the taken edge is recorded in *TAKEN_EDGE_P.
5734 If STMT produces a varying value, return SSA_PROP_VARYING. */
5736 static enum ssa_prop_result
5737 vrp_visit_stmt (tree stmt, edge *taken_edge_p, tree *output_p)
5743 if (dump_file && (dump_flags & TDF_DETAILS))
5745 fprintf (dump_file, "\nVisiting statement:\n");
5746 print_generic_stmt (dump_file, stmt, dump_flags);
5747 fprintf (dump_file, "\n");
5750 ann = stmt_ann (stmt);
5751 if (TREE_CODE (stmt) == GIMPLE_MODIFY_STMT)
5753 tree rhs = GIMPLE_STMT_OPERAND (stmt, 1);
5755 /* In general, assignments with virtual operands are not useful
5756 for deriving ranges, with the obvious exception of calls to
5757 builtin functions. */
5758 if ((TREE_CODE (rhs) == CALL_EXPR
5759 && TREE_CODE (CALL_EXPR_FN (rhs)) == ADDR_EXPR
5760 && DECL_P (TREE_OPERAND (CALL_EXPR_FN (rhs), 0))
5761 && DECL_IS_BUILTIN (TREE_OPERAND (CALL_EXPR_FN (rhs), 0)))
5762 || ZERO_SSA_OPERANDS (stmt, SSA_OP_ALL_VIRTUALS))
5763 return vrp_visit_assignment (stmt, output_p);
5765 else if (TREE_CODE (stmt) == COND_EXPR)
5766 return vrp_visit_cond_stmt (stmt, taken_edge_p);
5767 else if (TREE_CODE (stmt) == SWITCH_EXPR)
5768 return vrp_visit_switch_stmt (stmt, taken_edge_p);
5770 /* All other statements produce nothing of interest for VRP, so mark
5771 their outputs varying and prevent further simulation. */
5772 FOR_EACH_SSA_TREE_OPERAND (def, stmt, iter, SSA_OP_DEF)
5773 set_value_range_to_varying (get_value_range (def));
5775 return SSA_PROP_VARYING;
5779 /* Meet operation for value ranges. Given two value ranges VR0 and
5780 VR1, store in VR0 a range that contains both VR0 and VR1. This
5781 may not be the smallest possible such range. */
5784 vrp_meet (value_range_t *vr0, value_range_t *vr1)
5786 if (vr0->type == VR_UNDEFINED)
5788 copy_value_range (vr0, vr1);
5792 if (vr1->type == VR_UNDEFINED)
5794 /* Nothing to do. VR0 already has the resulting range. */
5798 if (vr0->type == VR_VARYING)
5800 /* Nothing to do. VR0 already has the resulting range. */
5804 if (vr1->type == VR_VARYING)
5806 set_value_range_to_varying (vr0);
5810 if (vr0->type == VR_RANGE && vr1->type == VR_RANGE)
5815 /* Compute the convex hull of the ranges. The lower limit of
5816 the new range is the minimum of the two ranges. If they
5817 cannot be compared, then give up. */
5818 cmp = compare_values (vr0->min, vr1->min);
5819 if (cmp == 0 || cmp == 1)
5826 /* Similarly, the upper limit of the new range is the maximum
5827 of the two ranges. If they cannot be compared, then
5829 cmp = compare_values (vr0->max, vr1->max);
5830 if (cmp == 0 || cmp == -1)
5837 /* Check for useless ranges. */
5838 if (INTEGRAL_TYPE_P (TREE_TYPE (min))
5839 && ((vrp_val_is_min (min) || is_overflow_infinity (min))
5840 && (vrp_val_is_max (max) || is_overflow_infinity (max))))
5843 /* The resulting set of equivalences is the intersection of
5845 if (vr0->equiv && vr1->equiv && vr0->equiv != vr1->equiv)
5846 bitmap_and_into (vr0->equiv, vr1->equiv);
5847 else if (vr0->equiv && !vr1->equiv)
5848 bitmap_clear (vr0->equiv);
5850 set_value_range (vr0, vr0->type, min, max, vr0->equiv);
5852 else if (vr0->type == VR_ANTI_RANGE && vr1->type == VR_ANTI_RANGE)
5854 /* Two anti-ranges meet only if their complements intersect.
5855 Only handle the case of identical ranges. */
5856 if (compare_values (vr0->min, vr1->min) == 0
5857 && compare_values (vr0->max, vr1->max) == 0
5858 && compare_values (vr0->min, vr0->max) == 0)
5860 /* The resulting set of equivalences is the intersection of
5862 if (vr0->equiv && vr1->equiv && vr0->equiv != vr1->equiv)
5863 bitmap_and_into (vr0->equiv, vr1->equiv);
5864 else if (vr0->equiv && !vr1->equiv)
5865 bitmap_clear (vr0->equiv);
5870 else if (vr0->type == VR_ANTI_RANGE || vr1->type == VR_ANTI_RANGE)
5872 /* For a numeric range [VAL1, VAL2] and an anti-range ~[VAL3, VAL4],
5873 only handle the case where the ranges have an empty intersection.
5874 The result of the meet operation is the anti-range. */
5875 if (!symbolic_range_p (vr0)
5876 && !symbolic_range_p (vr1)
5877 && !value_ranges_intersect_p (vr0, vr1))
5879 /* Copy most of VR1 into VR0. Don't copy VR1's equivalence
5880 set. We need to compute the intersection of the two
5881 equivalence sets. */
5882 if (vr1->type == VR_ANTI_RANGE)
5883 set_value_range (vr0, vr1->type, vr1->min, vr1->max, vr0->equiv);
5885 /* The resulting set of equivalences is the intersection of
5887 if (vr0->equiv && vr1->equiv && vr0->equiv != vr1->equiv)
5888 bitmap_and_into (vr0->equiv, vr1->equiv);
5889 else if (vr0->equiv && !vr1->equiv)
5890 bitmap_clear (vr0->equiv);
5901 /* Failed to find an efficient meet. Before giving up and setting
5902 the result to VARYING, see if we can at least derive a useful
5903 anti-range. FIXME, all this nonsense about distinguishing
5904 anti-ranges from ranges is necessary because of the odd
5905 semantics of range_includes_zero_p and friends. */
5906 if (!symbolic_range_p (vr0)
5907 && ((vr0->type == VR_RANGE && !range_includes_zero_p (vr0))
5908 || (vr0->type == VR_ANTI_RANGE && range_includes_zero_p (vr0)))
5909 && !symbolic_range_p (vr1)
5910 && ((vr1->type == VR_RANGE && !range_includes_zero_p (vr1))
5911 || (vr1->type == VR_ANTI_RANGE && range_includes_zero_p (vr1))))
5913 set_value_range_to_nonnull (vr0, TREE_TYPE (vr0->min));
5915 /* Since this meet operation did not result from the meeting of
5916 two equivalent names, VR0 cannot have any equivalences. */
5918 bitmap_clear (vr0->equiv);
5921 set_value_range_to_varying (vr0);
5925 /* Visit all arguments for PHI node PHI that flow through executable
5926 edges. If a valid value range can be derived from all the incoming
5927 value ranges, set a new range for the LHS of PHI. */
5929 static enum ssa_prop_result
5930 vrp_visit_phi_node (tree phi)
5933 tree lhs = PHI_RESULT (phi);
5934 value_range_t *lhs_vr = get_value_range (lhs);
5935 value_range_t vr_result = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
5936 int edges, old_edges;
5938 copy_value_range (&vr_result, lhs_vr);
5940 if (dump_file && (dump_flags & TDF_DETAILS))
5942 fprintf (dump_file, "\nVisiting PHI node: ");
5943 print_generic_expr (dump_file, phi, dump_flags);
5947 for (i = 0; i < PHI_NUM_ARGS (phi); i++)
5949 edge e = PHI_ARG_EDGE (phi, i);
5951 if (dump_file && (dump_flags & TDF_DETAILS))
5954 "\n Argument #%d (%d -> %d %sexecutable)\n",
5955 i, e->src->index, e->dest->index,
5956 (e->flags & EDGE_EXECUTABLE) ? "" : "not ");
5959 if (e->flags & EDGE_EXECUTABLE)
5961 tree arg = PHI_ARG_DEF (phi, i);
5962 value_range_t vr_arg;
5966 if (TREE_CODE (arg) == SSA_NAME)
5968 vr_arg = *(get_value_range (arg));
5972 if (is_overflow_infinity (arg))
5974 arg = copy_node (arg);
5975 TREE_OVERFLOW (arg) = 0;
5978 vr_arg.type = VR_RANGE;
5981 vr_arg.equiv = NULL;
5984 if (dump_file && (dump_flags & TDF_DETAILS))
5986 fprintf (dump_file, "\t");
5987 print_generic_expr (dump_file, arg, dump_flags);
5988 fprintf (dump_file, "\n\tValue: ");
5989 dump_value_range (dump_file, &vr_arg);
5990 fprintf (dump_file, "\n");
5993 vrp_meet (&vr_result, &vr_arg);
5995 if (vr_result.type == VR_VARYING)
6000 if (vr_result.type == VR_VARYING)
6003 old_edges = vr_phi_edge_counts[SSA_NAME_VERSION (lhs)];
6004 vr_phi_edge_counts[SSA_NAME_VERSION (lhs)] = edges;
6006 /* To prevent infinite iterations in the algorithm, derive ranges
6007 when the new value is slightly bigger or smaller than the
6008 previous one. We don't do this if we have seen a new executable
6009 edge; this helps us avoid an overflow infinity for conditionals
6010 which are not in a loop. */
6011 if (lhs_vr->type == VR_RANGE && vr_result.type == VR_RANGE
6012 && edges <= old_edges)
6014 if (!POINTER_TYPE_P (TREE_TYPE (lhs)))
6016 int cmp_min = compare_values (lhs_vr->min, vr_result.min);
6017 int cmp_max = compare_values (lhs_vr->max, vr_result.max);
6019 /* If the new minimum is smaller or larger than the previous
6020 one, go all the way to -INF. In the first case, to avoid
6021 iterating millions of times to reach -INF, and in the
6022 other case to avoid infinite bouncing between different
6024 if (cmp_min > 0 || cmp_min < 0)
6026 /* If we will end up with a (-INF, +INF) range, set it
6028 if (vrp_val_is_max (vr_result.max))
6031 if (!needs_overflow_infinity (TREE_TYPE (vr_result.min))
6032 || !vrp_var_may_overflow (lhs, phi))
6033 vr_result.min = TYPE_MIN_VALUE (TREE_TYPE (vr_result.min));
6034 else if (supports_overflow_infinity (TREE_TYPE (vr_result.min)))
6036 negative_overflow_infinity (TREE_TYPE (vr_result.min));
6041 /* Similarly, if the new maximum is smaller or larger than
6042 the previous one, go all the way to +INF. */
6043 if (cmp_max < 0 || cmp_max > 0)
6045 /* If we will end up with a (-INF, +INF) range, set it
6047 if (vrp_val_is_min (vr_result.min))
6050 if (!needs_overflow_infinity (TREE_TYPE (vr_result.max))
6051 || !vrp_var_may_overflow (lhs, phi))
6052 vr_result.max = TYPE_MAX_VALUE (TREE_TYPE (vr_result.max));
6053 else if (supports_overflow_infinity (TREE_TYPE (vr_result.max)))
6055 positive_overflow_infinity (TREE_TYPE (vr_result.max));
6062 /* If the new range is different than the previous value, keep
6064 if (update_value_range (lhs, &vr_result))
6065 return SSA_PROP_INTERESTING;
6067 /* Nothing changed, don't add outgoing edges. */
6068 return SSA_PROP_NOT_INTERESTING;
6070 /* No match found. Set the LHS to VARYING. */
6072 set_value_range_to_varying (lhs_vr);
6073 return SSA_PROP_VARYING;
6076 /* Simplify a division or modulo operator to a right shift or
6077 bitwise and if the first operand is unsigned or is greater
6078 than zero and the second operand is an exact power of two. */
6081 simplify_div_or_mod_using_ranges (tree stmt, tree rhs, enum tree_code rhs_code)
6084 tree op = TREE_OPERAND (rhs, 0);
6085 value_range_t *vr = get_value_range (TREE_OPERAND (rhs, 0));
6087 if (TYPE_UNSIGNED (TREE_TYPE (op)))
6089 val = integer_one_node;
6095 val = compare_range_with_value (GE_EXPR, vr, integer_zero_node, &sop);
6099 && integer_onep (val)
6100 && issue_strict_overflow_warning (WARN_STRICT_OVERFLOW_MISC))
6104 if (!EXPR_HAS_LOCATION (stmt))
6105 locus = input_location;
6107 locus = EXPR_LOCATION (stmt);
6108 warning (OPT_Wstrict_overflow,
6109 ("%Hassuming signed overflow does not occur when "
6110 "simplifying / or %% to >> or &"),
6115 if (val && integer_onep (val))
6118 tree op0 = TREE_OPERAND (rhs, 0);
6119 tree op1 = TREE_OPERAND (rhs, 1);
6121 if (rhs_code == TRUNC_DIV_EXPR)
6123 t = build_int_cst (NULL_TREE, tree_log2 (op1));
6124 t = build2 (RSHIFT_EXPR, TREE_TYPE (op0), op0, t);
6128 t = build_int_cst (TREE_TYPE (op1), 1);
6129 t = int_const_binop (MINUS_EXPR, op1, t, 0);
6130 t = fold_convert (TREE_TYPE (op0), t);
6131 t = build2 (BIT_AND_EXPR, TREE_TYPE (op0), op0, t);
6134 GIMPLE_STMT_OPERAND (stmt, 1) = t;
6139 /* If the operand to an ABS_EXPR is >= 0, then eliminate the
6140 ABS_EXPR. If the operand is <= 0, then simplify the
6141 ABS_EXPR into a NEGATE_EXPR. */
6144 simplify_abs_using_ranges (tree stmt, tree rhs)
6147 tree op = TREE_OPERAND (rhs, 0);
6148 tree type = TREE_TYPE (op);
6149 value_range_t *vr = get_value_range (TREE_OPERAND (rhs, 0));
6151 if (TYPE_UNSIGNED (type))
6153 val = integer_zero_node;
6159 val = compare_range_with_value (LE_EXPR, vr, integer_zero_node, &sop);
6163 val = compare_range_with_value (GE_EXPR, vr, integer_zero_node,
6168 if (integer_zerop (val))
6169 val = integer_one_node;
6170 else if (integer_onep (val))
6171 val = integer_zero_node;
6176 && (integer_onep (val) || integer_zerop (val)))
6180 if (sop && issue_strict_overflow_warning (WARN_STRICT_OVERFLOW_MISC))
6184 if (!EXPR_HAS_LOCATION (stmt))
6185 locus = input_location;
6187 locus = EXPR_LOCATION (stmt);
6188 warning (OPT_Wstrict_overflow,
6189 ("%Hassuming signed overflow does not occur when "
6190 "simplifying abs (X) to X or -X"),
6194 if (integer_onep (val))
6195 t = build1 (NEGATE_EXPR, TREE_TYPE (op), op);
6199 GIMPLE_STMT_OPERAND (stmt, 1) = t;
6205 /* We are comparing trees OP0 and OP1 using COND_CODE. OP0 has
6206 a known value range VR.
6208 If there is one and only one value which will satisfy the
6209 conditional, then return that value. Else return NULL. */
6212 test_for_singularity (enum tree_code cond_code, tree op0,
6213 tree op1, value_range_t *vr)
6218 /* Extract minimum/maximum values which satisfy the
6219 the conditional as it was written. */
6220 if (cond_code == LE_EXPR || cond_code == LT_EXPR)
6222 /* This should not be negative infinity; there is no overflow
6224 min = TYPE_MIN_VALUE (TREE_TYPE (op0));
6227 if (cond_code == LT_EXPR && !is_overflow_infinity (max))
6229 tree one = build_int_cst (TREE_TYPE (op0), 1);
6230 max = fold_build2 (MINUS_EXPR, TREE_TYPE (op0), max, one);
6232 TREE_NO_WARNING (max) = 1;
6235 else if (cond_code == GE_EXPR || cond_code == GT_EXPR)
6237 /* This should not be positive infinity; there is no overflow
6239 max = TYPE_MAX_VALUE (TREE_TYPE (op0));
6242 if (cond_code == GT_EXPR && !is_overflow_infinity (min))
6244 tree one = build_int_cst (TREE_TYPE (op0), 1);
6245 min = fold_build2 (PLUS_EXPR, TREE_TYPE (op0), min, one);
6247 TREE_NO_WARNING (min) = 1;
6251 /* Now refine the minimum and maximum values using any
6252 value range information we have for op0. */
6255 if (compare_values (vr->min, min) == -1)
6259 if (compare_values (vr->max, max) == 1)
6264 /* If the new min/max values have converged to a single value,
6265 then there is only one value which can satisfy the condition,
6266 return that value. */
6267 if (operand_equal_p (min, max, 0) && is_gimple_min_invariant (min))
6273 /* Simplify a conditional using a relational operator to an equality
6274 test if the range information indicates only one value can satisfy
6275 the original conditional. */
6278 simplify_cond_using_ranges (tree stmt)
6280 tree cond = COND_EXPR_COND (stmt);
6281 tree op0 = TREE_OPERAND (cond, 0);
6282 tree op1 = TREE_OPERAND (cond, 1);
6283 enum tree_code cond_code = TREE_CODE (cond);
6285 if (cond_code != NE_EXPR
6286 && cond_code != EQ_EXPR
6287 && TREE_CODE (op0) == SSA_NAME
6288 && INTEGRAL_TYPE_P (TREE_TYPE (op0))
6289 && is_gimple_min_invariant (op1))
6291 value_range_t *vr = get_value_range (op0);
6293 /* If we have range information for OP0, then we might be
6294 able to simplify this conditional. */
6295 if (vr->type == VR_RANGE)
6297 tree new = test_for_singularity (cond_code, op0, op1, vr);
6303 fprintf (dump_file, "Simplified relational ");
6304 print_generic_expr (dump_file, cond, 0);
6305 fprintf (dump_file, " into ");
6308 COND_EXPR_COND (stmt)
6309 = build2 (EQ_EXPR, boolean_type_node, op0, new);
6314 print_generic_expr (dump_file, COND_EXPR_COND (stmt), 0);
6315 fprintf (dump_file, "\n");
6321 /* Try again after inverting the condition. We only deal
6322 with integral types here, so no need to worry about
6323 issues with inverting FP comparisons. */
6324 cond_code = invert_tree_comparison (cond_code, false);
6325 new = test_for_singularity (cond_code, op0, op1, vr);
6331 fprintf (dump_file, "Simplified relational ");
6332 print_generic_expr (dump_file, cond, 0);
6333 fprintf (dump_file, " into ");
6336 COND_EXPR_COND (stmt)
6337 = build2 (NE_EXPR, boolean_type_node, op0, new);
6342 print_generic_expr (dump_file, COND_EXPR_COND (stmt), 0);
6343 fprintf (dump_file, "\n");
6352 /* Simplify a switch statement using the value range of the switch
6356 simplify_switch_using_ranges (tree stmt)
6358 tree op = TREE_OPERAND (stmt, 0);
6363 size_t i = 0, j = 0, n, n2;
6367 if (TREE_CODE (op) != SSA_NAME)
6370 vr = get_value_range (op);
6372 /* We can only handle integer ranges. */
6373 if (vr->type != VR_RANGE
6374 || symbolic_range_p (vr))
6377 /* Find case label for min/max of the value range. */
6378 vec = SWITCH_LABELS (stmt);
6379 n = TREE_VEC_LENGTH (vec);
6380 take_default = !find_case_label_range (vec, vr->min, vr->max, &i, &j);
6382 /* Bail out if this is just all edges taken. */
6388 /* Build a new vector of taken case labels. */
6389 vec2 = make_tree_vec (j - i + 1 + (int)take_default);
6390 for (n2 = 0; i <= j; ++i, ++n2)
6391 TREE_VEC_ELT (vec2, n2) = TREE_VEC_ELT (vec, i);
6393 /* Add the default edge, if necessary. */
6395 TREE_VEC_ELT (vec2, n2++) = TREE_VEC_ELT (vec, n - 1);
6397 /* Mark needed edges. */
6398 for (i = 0; i < n2; ++i)
6400 e = find_edge (bb_for_stmt (stmt),
6401 label_to_block (CASE_LABEL (TREE_VEC_ELT (vec2, i))));
6402 e->aux = (void *)-1;
6405 /* Queue not needed edges for later removal. */
6406 FOR_EACH_EDGE (e, ei, bb_for_stmt (stmt)->succs)
6408 if (e->aux == (void *)-1)
6414 if (dump_file && (dump_flags & TDF_DETAILS))
6416 fprintf (dump_file, "removing unreachable case label\n");
6418 VEC_safe_push (edge, heap, to_remove_edges, e);
6421 /* And queue an update for the stmt. */
6424 VEC_safe_push (switch_update, heap, to_update_switch_stmts, &su);
6427 /* Simplify STMT using ranges if possible. */
6430 simplify_stmt_using_ranges (tree stmt)
6432 if (TREE_CODE (stmt) == GIMPLE_MODIFY_STMT)
6434 tree rhs = GIMPLE_STMT_OPERAND (stmt, 1);
6435 enum tree_code rhs_code = TREE_CODE (rhs);
6437 /* Transform TRUNC_DIV_EXPR and TRUNC_MOD_EXPR into RSHIFT_EXPR
6438 and BIT_AND_EXPR respectively if the first operand is greater
6439 than zero and the second operand is an exact power of two. */
6440 if ((rhs_code == TRUNC_DIV_EXPR || rhs_code == TRUNC_MOD_EXPR)
6441 && INTEGRAL_TYPE_P (TREE_TYPE (TREE_OPERAND (rhs, 0)))
6442 && integer_pow2p (TREE_OPERAND (rhs, 1)))
6443 simplify_div_or_mod_using_ranges (stmt, rhs, rhs_code);
6445 /* Transform ABS (X) into X or -X as appropriate. */
6446 if (rhs_code == ABS_EXPR
6447 && TREE_CODE (TREE_OPERAND (rhs, 0)) == SSA_NAME
6448 && INTEGRAL_TYPE_P (TREE_TYPE (TREE_OPERAND (rhs, 0))))
6449 simplify_abs_using_ranges (stmt, rhs);
6451 else if (TREE_CODE (stmt) == COND_EXPR
6452 && COMPARISON_CLASS_P (COND_EXPR_COND (stmt)))
6453 simplify_cond_using_ranges (stmt);
6454 else if (TREE_CODE (stmt) == SWITCH_EXPR)
6455 simplify_switch_using_ranges (stmt);
6458 /* Stack of dest,src equivalency pairs that need to be restored after
6459 each attempt to thread a block's incoming edge to an outgoing edge.
6461 A NULL entry is used to mark the end of pairs which need to be
6463 static VEC(tree,heap) *stack;
6465 /* A trivial wrapper so that we can present the generic jump threading
6466 code with a simple API for simplifying statements. STMT is the
6467 statement we want to simplify, WITHIN_STMT provides the location
6468 for any overflow warnings. */
6471 simplify_stmt_for_jump_threading (tree stmt, tree within_stmt)
6473 /* We only use VRP information to simplify conditionals. This is
6474 overly conservative, but it's unclear if doing more would be
6475 worth the compile time cost. */
6476 if (TREE_CODE (stmt) != COND_EXPR)
6479 return vrp_evaluate_conditional (COND_EXPR_COND (stmt), within_stmt);
6482 /* Blocks which have more than one predecessor and more than
6483 one successor present jump threading opportunities. ie,
6484 when the block is reached from a specific predecessor, we
6485 may be able to determine which of the outgoing edges will
6486 be traversed. When this optimization applies, we are able
6487 to avoid conditionals at runtime and we may expose secondary
6488 optimization opportunities.
6490 This routine is effectively a driver for the generic jump
6491 threading code. It basically just presents the generic code
6492 with edges that may be suitable for jump threading.
6494 Unlike DOM, we do not iterate VRP if jump threading was successful.
6495 While iterating may expose new opportunities for VRP, it is expected
6496 those opportunities would be very limited and the compile time cost
6497 to expose those opportunities would be significant.
6499 As jump threading opportunities are discovered, they are registered
6500 for later realization. */
6503 identify_jump_threads (void)
6510 /* Ugh. When substituting values earlier in this pass we can
6511 wipe the dominance information. So rebuild the dominator
6512 information as we need it within the jump threading code. */
6513 calculate_dominance_info (CDI_DOMINATORS);
6515 /* We do not allow VRP information to be used for jump threading
6516 across a back edge in the CFG. Otherwise it becomes too
6517 difficult to avoid eliminating loop exit tests. Of course
6518 EDGE_DFS_BACK is not accurate at this time so we have to
6520 mark_dfs_back_edges ();
6522 /* Do not thread across edges we are about to remove. Just marking
6523 them as EDGE_DFS_BACK will do. */
6524 for (i = 0; VEC_iterate (edge, to_remove_edges, i, e); ++i)
6525 e->flags |= EDGE_DFS_BACK;
6527 /* Allocate our unwinder stack to unwind any temporary equivalences
6528 that might be recorded. */
6529 stack = VEC_alloc (tree, heap, 20);
6531 /* To avoid lots of silly node creation, we create a single
6532 conditional and just modify it in-place when attempting to
6534 dummy = build2 (EQ_EXPR, boolean_type_node, NULL, NULL);
6535 dummy = build3 (COND_EXPR, void_type_node, dummy, NULL, NULL);
6537 /* Walk through all the blocks finding those which present a
6538 potential jump threading opportunity. We could set this up
6539 as a dominator walker and record data during the walk, but
6540 I doubt it's worth the effort for the classes of jump
6541 threading opportunities we are trying to identify at this
6542 point in compilation. */
6547 /* If the generic jump threading code does not find this block
6548 interesting, then there is nothing to do. */
6549 if (! potentially_threadable_block (bb))
6552 /* We only care about blocks ending in a COND_EXPR. While there
6553 may be some value in handling SWITCH_EXPR here, I doubt it's
6554 terribly important. */
6555 last = bsi_stmt (bsi_last (bb));
6556 if (TREE_CODE (last) != COND_EXPR)
6559 /* We're basically looking for any kind of conditional with
6560 integral type arguments. */
6561 cond = COND_EXPR_COND (last);
6562 if ((TREE_CODE (cond) == SSA_NAME
6563 && INTEGRAL_TYPE_P (TREE_TYPE (cond)))
6564 || (COMPARISON_CLASS_P (cond)
6565 && TREE_CODE (TREE_OPERAND (cond, 0)) == SSA_NAME
6566 && INTEGRAL_TYPE_P (TREE_TYPE (TREE_OPERAND (cond, 0)))
6567 && (TREE_CODE (TREE_OPERAND (cond, 1)) == SSA_NAME
6568 || is_gimple_min_invariant (TREE_OPERAND (cond, 1)))
6569 && INTEGRAL_TYPE_P (TREE_TYPE (TREE_OPERAND (cond, 1)))))
6573 /* We've got a block with multiple predecessors and multiple
6574 successors which also ends in a suitable conditional. For
6575 each predecessor, see if we can thread it to a specific
6577 FOR_EACH_EDGE (e, ei, bb->preds)
6579 /* Do not thread across back edges or abnormal edges
6581 if (e->flags & (EDGE_DFS_BACK | EDGE_COMPLEX))
6584 thread_across_edge (dummy, e, true,
6586 simplify_stmt_for_jump_threading);
6591 /* We do not actually update the CFG or SSA graphs at this point as
6592 ASSERT_EXPRs are still in the IL and cfg cleanup code does not yet
6593 handle ASSERT_EXPRs gracefully. */
6596 /* We identified all the jump threading opportunities earlier, but could
6597 not transform the CFG at that time. This routine transforms the
6598 CFG and arranges for the dominator tree to be rebuilt if necessary.
6600 Note the SSA graph update will occur during the normal TODO
6601 processing by the pass manager. */
6603 finalize_jump_threads (void)
6605 thread_through_all_blocks (false);
6606 VEC_free (tree, heap, stack);
6610 /* Traverse all the blocks folding conditionals with known ranges. */
6616 prop_value_t *single_val_range;
6617 bool do_value_subst_p;
6621 fprintf (dump_file, "\nValue ranges after VRP:\n\n");
6622 dump_all_value_ranges (dump_file);
6623 fprintf (dump_file, "\n");
6626 /* We may have ended with ranges that have exactly one value. Those
6627 values can be substituted as any other copy/const propagated
6628 value using substitute_and_fold. */
6629 single_val_range = XCNEWVEC (prop_value_t, num_ssa_names);
6631 do_value_subst_p = false;
6632 for (i = 0; i < num_ssa_names; i++)
6634 && vr_value[i]->type == VR_RANGE
6635 && vr_value[i]->min == vr_value[i]->max)
6637 single_val_range[i].value = vr_value[i]->min;
6638 do_value_subst_p = true;
6641 if (!do_value_subst_p)
6643 /* We found no single-valued ranges, don't waste time trying to
6644 do single value substitution in substitute_and_fold. */
6645 free (single_val_range);
6646 single_val_range = NULL;
6649 substitute_and_fold (single_val_range, true);
6651 if (warn_array_bounds)
6652 check_all_array_refs ();
6654 /* We must identify jump threading opportunities before we release
6655 the datastructures built by VRP. */
6656 identify_jump_threads ();
6658 /* Free allocated memory. */
6659 for (i = 0; i < num_ssa_names; i++)
6662 BITMAP_FREE (vr_value[i]->equiv);
6666 free (single_val_range);
6668 free (vr_phi_edge_counts);
6670 /* So that we can distinguish between VRP data being available
6671 and not available. */
6673 vr_phi_edge_counts = NULL;
6676 /* Calculates number of iterations for all loops, to ensure that they are
6680 record_numbers_of_iterations (void)
6685 FOR_EACH_LOOP (li, loop, 0)
6687 number_of_latch_executions (loop);
6691 /* Main entry point to VRP (Value Range Propagation). This pass is
6692 loosely based on J. R. C. Patterson, ``Accurate Static Branch
6693 Prediction by Value Range Propagation,'' in SIGPLAN Conference on
6694 Programming Language Design and Implementation, pp. 67-78, 1995.
6695 Also available at http://citeseer.ist.psu.edu/patterson95accurate.html
6697 This is essentially an SSA-CCP pass modified to deal with ranges
6698 instead of constants.
6700 While propagating ranges, we may find that two or more SSA name
6701 have equivalent, though distinct ranges. For instance,
6704 2 p_4 = ASSERT_EXPR <p_3, p_3 != 0>
6706 4 p_5 = ASSERT_EXPR <p_4, p_4 == q_2>;
6710 In the code above, pointer p_5 has range [q_2, q_2], but from the
6711 code we can also determine that p_5 cannot be NULL and, if q_2 had
6712 a non-varying range, p_5's range should also be compatible with it.
6714 These equivalences are created by two expressions: ASSERT_EXPR and
6715 copy operations. Since p_5 is an assertion on p_4, and p_4 was the
6716 result of another assertion, then we can use the fact that p_5 and
6717 p_4 are equivalent when evaluating p_5's range.
6719 Together with value ranges, we also propagate these equivalences
6720 between names so that we can take advantage of information from
6721 multiple ranges when doing final replacement. Note that this
6722 equivalency relation is transitive but not symmetric.
6724 In the example above, p_5 is equivalent to p_4, q_2 and p_3, but we
6725 cannot assert that q_2 is equivalent to p_5 because q_2 may be used
6726 in contexts where that assertion does not hold (e.g., in line 6).
6728 TODO, the main difference between this pass and Patterson's is that
6729 we do not propagate edge probabilities. We only compute whether
6730 edges can be taken or not. That is, instead of having a spectrum
6731 of jump probabilities between 0 and 1, we only deal with 0, 1 and
6732 DON'T KNOW. In the future, it may be worthwhile to propagate
6733 probabilities to aid branch prediction. */
6742 loop_optimizer_init (LOOPS_NORMAL | LOOPS_HAVE_RECORDED_EXITS);
6743 rewrite_into_loop_closed_ssa (NULL, TODO_update_ssa);
6746 insert_range_assertions ();
6748 /* Compute the # of iterations for each loop before we start the VRP
6749 analysis. The value ranges determined by VRP are used in expression
6750 simplification, that is also used by the # of iterations analysis.
6751 However, in the middle of the VRP analysis, the value ranges do not take
6752 all the possible paths in CFG into account, so they do not have to be
6753 correct, and the # of iterations analysis can obtain wrong results.
6754 This is a problem, since the results of the # of iterations analysis
6755 are cached, so these mistakes would not be corrected when the value
6756 ranges are corrected. */
6757 record_numbers_of_iterations ();
6759 to_remove_edges = VEC_alloc (edge, heap, 10);
6760 to_update_switch_stmts = VEC_alloc (switch_update, heap, 5);
6763 ssa_propagate (vrp_visit_stmt, vrp_visit_phi_node);
6766 /* ASSERT_EXPRs must be removed before finalizing jump threads
6767 as finalizing jump threads calls the CFG cleanup code which
6768 does not properly handle ASSERT_EXPRs. */
6769 remove_range_assertions ();
6771 /* If we exposed any new variables, go ahead and put them into
6772 SSA form now, before we handle jump threading. This simplifies
6773 interactions between rewriting of _DECL nodes into SSA form
6774 and rewriting SSA_NAME nodes into SSA form after block
6775 duplication and CFG manipulation. */
6776 update_ssa (TODO_update_ssa);
6778 finalize_jump_threads ();
6780 /* Remove dead edges from SWITCH_EXPR optimization. This leaves the
6781 CFG in a broken state and requires a cfg_cleanup run. */
6782 for (i = 0; VEC_iterate (edge, to_remove_edges, i, e); ++i)
6784 /* Update SWITCH_EXPR case label vector. */
6785 for (i = 0; VEC_iterate (switch_update, to_update_switch_stmts, i, su); ++i)
6786 SWITCH_LABELS (su->stmt) = su->vec;
6788 if (VEC_length (edge, to_remove_edges) > 0)
6790 free_dominance_info (CDI_DOMINATORS);
6791 cleanup_tree_cfg ();
6794 VEC_free (edge, heap, to_remove_edges);
6795 VEC_free (switch_update, heap, to_update_switch_stmts);
6798 loop_optimizer_finalize ();
6806 return flag_tree_vrp != 0;
6809 struct gimple_opt_pass pass_vrp =
6814 gate_vrp, /* gate */
6815 execute_vrp, /* execute */
6818 0, /* static_pass_number */
6819 TV_TREE_VRP, /* tv_id */
6820 PROP_ssa | PROP_alias, /* properties_required */
6821 0, /* properties_provided */
6822 0, /* properties_destroyed */
6823 0, /* todo_flags_start */
6828 | TODO_update_ssa /* todo_flags_finish */