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 == NON_LVALUE_EXPR
2296 || code == CONJ_EXPR)
2298 set_value_range_to_varying (vr);
2302 /* Get value ranges for the operand. For constant operands, create
2303 a new value range with the operand to simplify processing. */
2304 if (TREE_CODE (op0) == SSA_NAME)
2305 vr0 = *(get_value_range (op0));
2306 else if (is_gimple_min_invariant (op0))
2307 set_value_range_to_value (&vr0, op0, NULL);
2309 set_value_range_to_varying (&vr0);
2311 /* If VR0 is UNDEFINED, so is the result. */
2312 if (vr0.type == VR_UNDEFINED)
2314 set_value_range_to_undefined (vr);
2318 /* Refuse to operate on symbolic ranges, or if neither operand is
2319 a pointer or integral type. */
2320 if ((!INTEGRAL_TYPE_P (TREE_TYPE (op0))
2321 && !POINTER_TYPE_P (TREE_TYPE (op0)))
2322 || (vr0.type != VR_VARYING
2323 && symbolic_range_p (&vr0)))
2325 set_value_range_to_varying (vr);
2329 /* If the expression involves pointers, we are only interested in
2330 determining if it evaluates to NULL [0, 0] or non-NULL (~[0, 0]). */
2331 if (POINTER_TYPE_P (type) || POINTER_TYPE_P (TREE_TYPE (op0)))
2336 if (range_is_nonnull (&vr0)
2337 || (tree_unary_nonzero_warnv_p (code, type, op0, &sop)
2339 set_value_range_to_nonnull (vr, type);
2340 else if (range_is_null (&vr0))
2341 set_value_range_to_null (vr, type);
2343 set_value_range_to_varying (vr);
2348 /* Handle unary expressions on integer ranges. */
2349 if ((code == NOP_EXPR
2350 || code == CONVERT_EXPR)
2351 && INTEGRAL_TYPE_P (type)
2352 && INTEGRAL_TYPE_P (TREE_TYPE (op0)))
2354 tree inner_type = TREE_TYPE (op0);
2355 tree outer_type = type;
2357 /* Always use base-types here. This is important for the
2358 correct signedness. */
2359 if (TREE_TYPE (inner_type))
2360 inner_type = TREE_TYPE (inner_type);
2361 if (TREE_TYPE (outer_type))
2362 outer_type = TREE_TYPE (outer_type);
2364 /* If VR0 is varying and we increase the type precision, assume
2365 a full range for the following transformation. */
2366 if (vr0.type == VR_VARYING
2367 && TYPE_PRECISION (inner_type) < TYPE_PRECISION (outer_type))
2369 vr0.type = VR_RANGE;
2370 vr0.min = TYPE_MIN_VALUE (inner_type);
2371 vr0.max = TYPE_MAX_VALUE (inner_type);
2374 /* If VR0 is a constant range or anti-range and the conversion is
2375 not truncating we can convert the min and max values and
2376 canonicalize the resulting range. Otherwise we can do the
2377 conversion if the size of the range is less than what the
2378 precision of the target type can represent and the range is
2379 not an anti-range. */
2380 if ((vr0.type == VR_RANGE
2381 || vr0.type == VR_ANTI_RANGE)
2382 && TREE_CODE (vr0.min) == INTEGER_CST
2383 && TREE_CODE (vr0.max) == INTEGER_CST
2384 && !is_overflow_infinity (vr0.min)
2385 && !is_overflow_infinity (vr0.max)
2386 && (TYPE_PRECISION (outer_type) >= TYPE_PRECISION (inner_type)
2387 || (vr0.type == VR_RANGE
2388 && integer_zerop (int_const_binop (RSHIFT_EXPR,
2389 int_const_binop (MINUS_EXPR, vr0.max, vr0.min, 0),
2390 size_int (TYPE_PRECISION (outer_type)), 0)))))
2392 tree new_min, new_max;
2393 new_min = force_fit_type_double (outer_type,
2394 TREE_INT_CST_LOW (vr0.min),
2395 TREE_INT_CST_HIGH (vr0.min), 0, 0);
2396 new_max = force_fit_type_double (outer_type,
2397 TREE_INT_CST_LOW (vr0.max),
2398 TREE_INT_CST_HIGH (vr0.max), 0, 0);
2399 set_and_canonicalize_value_range (vr, vr0.type,
2400 new_min, new_max, NULL);
2404 set_value_range_to_varying (vr);
2408 /* Conversion of a VR_VARYING value to a wider type can result
2409 in a usable range. So wait until after we've handled conversions
2410 before dropping the result to VR_VARYING if we had a source
2411 operand that is VR_VARYING. */
2412 if (vr0.type == VR_VARYING)
2414 set_value_range_to_varying (vr);
2418 /* Apply the operation to each end of the range and see what we end
2420 if (code == NEGATE_EXPR
2421 && !TYPE_UNSIGNED (type))
2423 /* NEGATE_EXPR flips the range around. We need to treat
2424 TYPE_MIN_VALUE specially. */
2425 if (is_positive_overflow_infinity (vr0.max))
2426 min = negative_overflow_infinity (type);
2427 else if (is_negative_overflow_infinity (vr0.max))
2428 min = positive_overflow_infinity (type);
2429 else if (!vrp_val_is_min (vr0.max))
2430 min = fold_unary_to_constant (code, type, vr0.max);
2431 else if (needs_overflow_infinity (type))
2433 if (supports_overflow_infinity (type)
2434 && !is_overflow_infinity (vr0.min)
2435 && !vrp_val_is_min (vr0.min))
2436 min = positive_overflow_infinity (type);
2439 set_value_range_to_varying (vr);
2444 min = TYPE_MIN_VALUE (type);
2446 if (is_positive_overflow_infinity (vr0.min))
2447 max = negative_overflow_infinity (type);
2448 else if (is_negative_overflow_infinity (vr0.min))
2449 max = positive_overflow_infinity (type);
2450 else if (!vrp_val_is_min (vr0.min))
2451 max = fold_unary_to_constant (code, type, vr0.min);
2452 else if (needs_overflow_infinity (type))
2454 if (supports_overflow_infinity (type))
2455 max = positive_overflow_infinity (type);
2458 set_value_range_to_varying (vr);
2463 max = TYPE_MIN_VALUE (type);
2465 else if (code == NEGATE_EXPR
2466 && TYPE_UNSIGNED (type))
2468 if (!range_includes_zero_p (&vr0))
2470 max = fold_unary_to_constant (code, type, vr0.min);
2471 min = fold_unary_to_constant (code, type, vr0.max);
2475 if (range_is_null (&vr0))
2476 set_value_range_to_null (vr, type);
2478 set_value_range_to_varying (vr);
2482 else if (code == ABS_EXPR
2483 && !TYPE_UNSIGNED (type))
2485 /* -TYPE_MIN_VALUE = TYPE_MIN_VALUE with flag_wrapv so we can't get a
2487 if (!TYPE_OVERFLOW_UNDEFINED (type)
2488 && ((vr0.type == VR_RANGE
2489 && vrp_val_is_min (vr0.min))
2490 || (vr0.type == VR_ANTI_RANGE
2491 && !vrp_val_is_min (vr0.min)
2492 && !range_includes_zero_p (&vr0))))
2494 set_value_range_to_varying (vr);
2498 /* ABS_EXPR may flip the range around, if the original range
2499 included negative values. */
2500 if (is_overflow_infinity (vr0.min))
2501 min = positive_overflow_infinity (type);
2502 else if (!vrp_val_is_min (vr0.min))
2503 min = fold_unary_to_constant (code, type, vr0.min);
2504 else if (!needs_overflow_infinity (type))
2505 min = TYPE_MAX_VALUE (type);
2506 else if (supports_overflow_infinity (type))
2507 min = positive_overflow_infinity (type);
2510 set_value_range_to_varying (vr);
2514 if (is_overflow_infinity (vr0.max))
2515 max = positive_overflow_infinity (type);
2516 else if (!vrp_val_is_min (vr0.max))
2517 max = fold_unary_to_constant (code, type, vr0.max);
2518 else if (!needs_overflow_infinity (type))
2519 max = TYPE_MAX_VALUE (type);
2520 else if (supports_overflow_infinity (type))
2521 max = positive_overflow_infinity (type);
2524 set_value_range_to_varying (vr);
2528 cmp = compare_values (min, max);
2530 /* If a VR_ANTI_RANGEs contains zero, then we have
2531 ~[-INF, min(MIN, MAX)]. */
2532 if (vr0.type == VR_ANTI_RANGE)
2534 if (range_includes_zero_p (&vr0))
2536 /* Take the lower of the two values. */
2540 /* Create ~[-INF, min (abs(MIN), abs(MAX))]
2541 or ~[-INF + 1, min (abs(MIN), abs(MAX))] when
2542 flag_wrapv is set and the original anti-range doesn't include
2543 TYPE_MIN_VALUE, remember -TYPE_MIN_VALUE = TYPE_MIN_VALUE. */
2544 if (TYPE_OVERFLOW_WRAPS (type))
2546 tree type_min_value = TYPE_MIN_VALUE (type);
2548 min = (vr0.min != type_min_value
2549 ? int_const_binop (PLUS_EXPR, type_min_value,
2550 integer_one_node, 0)
2555 if (overflow_infinity_range_p (&vr0))
2556 min = negative_overflow_infinity (type);
2558 min = TYPE_MIN_VALUE (type);
2563 /* All else has failed, so create the range [0, INF], even for
2564 flag_wrapv since TYPE_MIN_VALUE is in the original
2566 vr0.type = VR_RANGE;
2567 min = build_int_cst (type, 0);
2568 if (needs_overflow_infinity (type))
2570 if (supports_overflow_infinity (type))
2571 max = positive_overflow_infinity (type);
2574 set_value_range_to_varying (vr);
2579 max = TYPE_MAX_VALUE (type);
2583 /* If the range contains zero then we know that the minimum value in the
2584 range will be zero. */
2585 else if (range_includes_zero_p (&vr0))
2589 min = build_int_cst (type, 0);
2593 /* If the range was reversed, swap MIN and MAX. */
2604 /* Otherwise, operate on each end of the range. */
2605 min = fold_unary_to_constant (code, type, vr0.min);
2606 max = fold_unary_to_constant (code, type, vr0.max);
2608 if (needs_overflow_infinity (type))
2610 gcc_assert (code != NEGATE_EXPR && code != ABS_EXPR);
2612 /* If both sides have overflowed, we don't know
2614 if ((is_overflow_infinity (vr0.min)
2615 || TREE_OVERFLOW (min))
2616 && (is_overflow_infinity (vr0.max)
2617 || TREE_OVERFLOW (max)))
2619 set_value_range_to_varying (vr);
2623 if (is_overflow_infinity (vr0.min))
2625 else if (TREE_OVERFLOW (min))
2627 if (supports_overflow_infinity (type))
2628 min = (tree_int_cst_sgn (min) >= 0
2629 ? positive_overflow_infinity (TREE_TYPE (min))
2630 : negative_overflow_infinity (TREE_TYPE (min)));
2633 set_value_range_to_varying (vr);
2638 if (is_overflow_infinity (vr0.max))
2640 else if (TREE_OVERFLOW (max))
2642 if (supports_overflow_infinity (type))
2643 max = (tree_int_cst_sgn (max) >= 0
2644 ? positive_overflow_infinity (TREE_TYPE (max))
2645 : negative_overflow_infinity (TREE_TYPE (max)));
2648 set_value_range_to_varying (vr);
2655 cmp = compare_values (min, max);
2656 if (cmp == -2 || cmp == 1)
2658 /* If the new range has its limits swapped around (MIN > MAX),
2659 then the operation caused one of them to wrap around, mark
2660 the new range VARYING. */
2661 set_value_range_to_varying (vr);
2664 set_value_range (vr, vr0.type, min, max, NULL);
2668 /* Extract range information from a conditional expression EXPR based on
2669 the ranges of each of its operands and the expression code. */
2672 extract_range_from_cond_expr (value_range_t *vr, tree expr)
2675 value_range_t vr0 = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
2676 value_range_t vr1 = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
2678 /* Get value ranges for each operand. For constant operands, create
2679 a new value range with the operand to simplify processing. */
2680 op0 = COND_EXPR_THEN (expr);
2681 if (TREE_CODE (op0) == SSA_NAME)
2682 vr0 = *(get_value_range (op0));
2683 else if (is_gimple_min_invariant (op0))
2684 set_value_range_to_value (&vr0, op0, NULL);
2686 set_value_range_to_varying (&vr0);
2688 op1 = COND_EXPR_ELSE (expr);
2689 if (TREE_CODE (op1) == SSA_NAME)
2690 vr1 = *(get_value_range (op1));
2691 else if (is_gimple_min_invariant (op1))
2692 set_value_range_to_value (&vr1, op1, NULL);
2694 set_value_range_to_varying (&vr1);
2696 /* The resulting value range is the union of the operand ranges */
2697 vrp_meet (&vr0, &vr1);
2698 copy_value_range (vr, &vr0);
2702 /* Extract range information from a comparison expression EXPR based
2703 on the range of its operand and the expression code. */
2706 extract_range_from_comparison (value_range_t *vr, enum tree_code code,
2707 tree type, tree op0, tree op1)
2710 tree val = vrp_evaluate_conditional_warnv_with_ops (code,
2715 /* A disadvantage of using a special infinity as an overflow
2716 representation is that we lose the ability to record overflow
2717 when we don't have an infinity. So we have to ignore a result
2718 which relies on overflow. */
2720 if (val && !is_overflow_infinity (val) && !sop)
2722 /* Since this expression was found on the RHS of an assignment,
2723 its type may be different from _Bool. Convert VAL to EXPR's
2725 val = fold_convert (type, val);
2726 if (is_gimple_min_invariant (val))
2727 set_value_range_to_value (vr, val, vr->equiv);
2729 set_value_range (vr, VR_RANGE, val, val, vr->equiv);
2732 /* The result of a comparison is always true or false. */
2733 set_value_range_to_truthvalue (vr, type);
2737 /* Try to compute a useful range out of expression EXPR and store it
2741 extract_range_from_expr (value_range_t *vr, tree expr)
2743 enum tree_code code = TREE_CODE (expr);
2745 if (code == ASSERT_EXPR)
2746 extract_range_from_assert (vr, expr);
2747 else if (code == SSA_NAME)
2748 extract_range_from_ssa_name (vr, expr);
2749 else if (TREE_CODE_CLASS (code) == tcc_binary
2750 || code == TRUTH_AND_EXPR
2751 || code == TRUTH_OR_EXPR
2752 || code == TRUTH_XOR_EXPR)
2753 extract_range_from_binary_expr (vr, TREE_CODE (expr), TREE_TYPE (expr),
2754 TREE_OPERAND (expr, 0),
2755 TREE_OPERAND (expr, 1));
2756 else if (TREE_CODE_CLASS (code) == tcc_unary)
2757 extract_range_from_unary_expr (vr, TREE_CODE (expr), TREE_TYPE (expr),
2758 TREE_OPERAND (expr, 0));
2759 else if (code == COND_EXPR)
2760 extract_range_from_cond_expr (vr, expr);
2761 else if (TREE_CODE_CLASS (code) == tcc_comparison)
2762 extract_range_from_comparison (vr, TREE_CODE (expr), TREE_TYPE (expr),
2763 TREE_OPERAND (expr, 0),
2764 TREE_OPERAND (expr, 1));
2765 else if (is_gimple_min_invariant (expr))
2766 set_value_range_to_value (vr, expr, NULL);
2768 set_value_range_to_varying (vr);
2770 /* If we got a varying range from the tests above, try a final
2771 time to derive a nonnegative or nonzero range. This time
2772 relying primarily on generic routines in fold in conjunction
2774 if (vr->type == VR_VARYING)
2778 if (INTEGRAL_TYPE_P (TREE_TYPE (expr))
2779 && vrp_expr_computes_nonnegative (expr, &sop))
2780 set_value_range_to_nonnegative (vr, TREE_TYPE (expr),
2781 sop || is_overflow_infinity (expr));
2782 else if (vrp_expr_computes_nonzero (expr, &sop)
2784 set_value_range_to_nonnull (vr, TREE_TYPE (expr));
2788 /* Given a range VR, a LOOP and a variable VAR, determine whether it
2789 would be profitable to adjust VR using scalar evolution information
2790 for VAR. If so, update VR with the new limits. */
2793 adjust_range_with_scev (value_range_t *vr, struct loop *loop, tree stmt,
2796 tree init, step, chrec, tmin, tmax, min, max, type;
2797 enum ev_direction dir;
2799 /* TODO. Don't adjust anti-ranges. An anti-range may provide
2800 better opportunities than a regular range, but I'm not sure. */
2801 if (vr->type == VR_ANTI_RANGE)
2804 /* Ensure that there are not values in the scev cache based on assumptions
2805 on ranges of ssa names that were changed
2806 (in set_value_range/set_value_range_to_varying). Preserve cached numbers
2807 of iterations, that were computed before the start of VRP (we do not
2808 recompute these each time to save the compile time). */
2809 scev_reset_except_niters ();
2811 chrec = instantiate_parameters (loop, analyze_scalar_evolution (loop, var));
2813 /* Like in PR19590, scev can return a constant function. */
2814 if (is_gimple_min_invariant (chrec))
2816 set_value_range_to_value (vr, chrec, vr->equiv);
2820 if (TREE_CODE (chrec) != POLYNOMIAL_CHREC)
2823 init = initial_condition_in_loop_num (chrec, loop->num);
2824 step = evolution_part_in_loop_num (chrec, loop->num);
2826 /* If STEP is symbolic, we can't know whether INIT will be the
2827 minimum or maximum value in the range. Also, unless INIT is
2828 a simple expression, compare_values and possibly other functions
2829 in tree-vrp won't be able to handle it. */
2830 if (step == NULL_TREE
2831 || !is_gimple_min_invariant (step)
2832 || !valid_value_p (init))
2835 dir = scev_direction (chrec);
2836 if (/* Do not adjust ranges if we do not know whether the iv increases
2837 or decreases, ... */
2838 dir == EV_DIR_UNKNOWN
2839 /* ... or if it may wrap. */
2840 || scev_probably_wraps_p (init, step, stmt, get_chrec_loop (chrec),
2844 /* We use TYPE_MIN_VALUE and TYPE_MAX_VALUE here instead of
2845 negative_overflow_infinity and positive_overflow_infinity,
2846 because we have concluded that the loop probably does not
2849 type = TREE_TYPE (var);
2850 if (POINTER_TYPE_P (type) || !TYPE_MIN_VALUE (type))
2851 tmin = lower_bound_in_type (type, type);
2853 tmin = TYPE_MIN_VALUE (type);
2854 if (POINTER_TYPE_P (type) || !TYPE_MAX_VALUE (type))
2855 tmax = upper_bound_in_type (type, type);
2857 tmax = TYPE_MAX_VALUE (type);
2859 if (vr->type == VR_VARYING || vr->type == VR_UNDEFINED)
2864 /* For VARYING or UNDEFINED ranges, just about anything we get
2865 from scalar evolutions should be better. */
2867 if (dir == EV_DIR_DECREASES)
2872 /* If we would create an invalid range, then just assume we
2873 know absolutely nothing. This may be over-conservative,
2874 but it's clearly safe, and should happen only in unreachable
2875 parts of code, or for invalid programs. */
2876 if (compare_values (min, max) == 1)
2879 set_value_range (vr, VR_RANGE, min, max, vr->equiv);
2881 else if (vr->type == VR_RANGE)
2886 if (dir == EV_DIR_DECREASES)
2888 /* INIT is the maximum value. If INIT is lower than VR->MAX
2889 but no smaller than VR->MIN, set VR->MAX to INIT. */
2890 if (compare_values (init, max) == -1)
2894 /* If we just created an invalid range with the minimum
2895 greater than the maximum, we fail conservatively.
2896 This should happen only in unreachable
2897 parts of code, or for invalid programs. */
2898 if (compare_values (min, max) == 1)
2902 /* According to the loop information, the variable does not
2903 overflow. If we think it does, probably because of an
2904 overflow due to arithmetic on a different INF value,
2906 if (is_negative_overflow_infinity (min))
2911 /* If INIT is bigger than VR->MIN, set VR->MIN to INIT. */
2912 if (compare_values (init, min) == 1)
2916 /* Again, avoid creating invalid range by failing. */
2917 if (compare_values (min, max) == 1)
2921 if (is_positive_overflow_infinity (max))
2925 set_value_range (vr, VR_RANGE, min, max, vr->equiv);
2929 /* Return true if VAR may overflow at STMT. This checks any available
2930 loop information to see if we can determine that VAR does not
2934 vrp_var_may_overflow (tree var, tree stmt)
2937 tree chrec, init, step;
2939 if (current_loops == NULL)
2942 l = loop_containing_stmt (stmt);
2946 chrec = instantiate_parameters (l, analyze_scalar_evolution (l, var));
2947 if (TREE_CODE (chrec) != POLYNOMIAL_CHREC)
2950 init = initial_condition_in_loop_num (chrec, l->num);
2951 step = evolution_part_in_loop_num (chrec, l->num);
2953 if (step == NULL_TREE
2954 || !is_gimple_min_invariant (step)
2955 || !valid_value_p (init))
2958 /* If we get here, we know something useful about VAR based on the
2959 loop information. If it wraps, it may overflow. */
2961 if (scev_probably_wraps_p (init, step, stmt, get_chrec_loop (chrec),
2965 if (dump_file && (dump_flags & TDF_DETAILS) != 0)
2967 print_generic_expr (dump_file, var, 0);
2968 fprintf (dump_file, ": loop information indicates does not overflow\n");
2975 /* Given two numeric value ranges VR0, VR1 and a comparison code COMP:
2977 - Return BOOLEAN_TRUE_NODE if VR0 COMP VR1 always returns true for
2978 all the values in the ranges.
2980 - Return BOOLEAN_FALSE_NODE if the comparison always returns false.
2982 - Return NULL_TREE if it is not always possible to determine the
2983 value of the comparison.
2985 Also set *STRICT_OVERFLOW_P to indicate whether a range with an
2986 overflow infinity was used in the test. */
2990 compare_ranges (enum tree_code comp, value_range_t *vr0, value_range_t *vr1,
2991 bool *strict_overflow_p)
2993 /* VARYING or UNDEFINED ranges cannot be compared. */
2994 if (vr0->type == VR_VARYING
2995 || vr0->type == VR_UNDEFINED
2996 || vr1->type == VR_VARYING
2997 || vr1->type == VR_UNDEFINED)
3000 /* Anti-ranges need to be handled separately. */
3001 if (vr0->type == VR_ANTI_RANGE || vr1->type == VR_ANTI_RANGE)
3003 /* If both are anti-ranges, then we cannot compute any
3005 if (vr0->type == VR_ANTI_RANGE && vr1->type == VR_ANTI_RANGE)
3008 /* These comparisons are never statically computable. */
3015 /* Equality can be computed only between a range and an
3016 anti-range. ~[VAL1, VAL2] == [VAL1, VAL2] is always false. */
3017 if (vr0->type == VR_RANGE)
3019 /* To simplify processing, make VR0 the anti-range. */
3020 value_range_t *tmp = vr0;
3025 gcc_assert (comp == NE_EXPR || comp == EQ_EXPR);
3027 if (compare_values_warnv (vr0->min, vr1->min, strict_overflow_p) == 0
3028 && compare_values_warnv (vr0->max, vr1->max, strict_overflow_p) == 0)
3029 return (comp == NE_EXPR) ? boolean_true_node : boolean_false_node;
3034 if (!usable_range_p (vr0, strict_overflow_p)
3035 || !usable_range_p (vr1, strict_overflow_p))
3038 /* Simplify processing. If COMP is GT_EXPR or GE_EXPR, switch the
3039 operands around and change the comparison code. */
3040 if (comp == GT_EXPR || comp == GE_EXPR)
3043 comp = (comp == GT_EXPR) ? LT_EXPR : LE_EXPR;
3049 if (comp == EQ_EXPR)
3051 /* Equality may only be computed if both ranges represent
3052 exactly one value. */
3053 if (compare_values_warnv (vr0->min, vr0->max, strict_overflow_p) == 0
3054 && compare_values_warnv (vr1->min, vr1->max, strict_overflow_p) == 0)
3056 int cmp_min = compare_values_warnv (vr0->min, vr1->min,
3058 int cmp_max = compare_values_warnv (vr0->max, vr1->max,
3060 if (cmp_min == 0 && cmp_max == 0)
3061 return boolean_true_node;
3062 else if (cmp_min != -2 && cmp_max != -2)
3063 return boolean_false_node;
3065 /* If [V0_MIN, V1_MAX] < [V1_MIN, V1_MAX] then V0 != V1. */
3066 else if (compare_values_warnv (vr0->min, vr1->max,
3067 strict_overflow_p) == 1
3068 || compare_values_warnv (vr1->min, vr0->max,
3069 strict_overflow_p) == 1)
3070 return boolean_false_node;
3074 else if (comp == NE_EXPR)
3078 /* If VR0 is completely to the left or completely to the right
3079 of VR1, they are always different. Notice that we need to
3080 make sure that both comparisons yield similar results to
3081 avoid comparing values that cannot be compared at
3083 cmp1 = compare_values_warnv (vr0->max, vr1->min, strict_overflow_p);
3084 cmp2 = compare_values_warnv (vr0->min, vr1->max, strict_overflow_p);
3085 if ((cmp1 == -1 && cmp2 == -1) || (cmp1 == 1 && cmp2 == 1))
3086 return boolean_true_node;
3088 /* If VR0 and VR1 represent a single value and are identical,
3090 else if (compare_values_warnv (vr0->min, vr0->max,
3091 strict_overflow_p) == 0
3092 && compare_values_warnv (vr1->min, vr1->max,
3093 strict_overflow_p) == 0
3094 && compare_values_warnv (vr0->min, vr1->min,
3095 strict_overflow_p) == 0
3096 && compare_values_warnv (vr0->max, vr1->max,
3097 strict_overflow_p) == 0)
3098 return boolean_false_node;
3100 /* Otherwise, they may or may not be different. */
3104 else if (comp == LT_EXPR || comp == LE_EXPR)
3108 /* If VR0 is to the left of VR1, return true. */
3109 tst = compare_values_warnv (vr0->max, vr1->min, strict_overflow_p);
3110 if ((comp == LT_EXPR && tst == -1)
3111 || (comp == LE_EXPR && (tst == -1 || tst == 0)))
3113 if (overflow_infinity_range_p (vr0)
3114 || overflow_infinity_range_p (vr1))
3115 *strict_overflow_p = true;
3116 return boolean_true_node;
3119 /* If VR0 is to the right of VR1, return false. */
3120 tst = compare_values_warnv (vr0->min, vr1->max, strict_overflow_p);
3121 if ((comp == LT_EXPR && (tst == 0 || tst == 1))
3122 || (comp == LE_EXPR && tst == 1))
3124 if (overflow_infinity_range_p (vr0)
3125 || overflow_infinity_range_p (vr1))
3126 *strict_overflow_p = true;
3127 return boolean_false_node;
3130 /* Otherwise, we don't know. */
3138 /* Given a value range VR, a value VAL and a comparison code COMP, return
3139 BOOLEAN_TRUE_NODE if VR COMP VAL always returns true for all the
3140 values in VR. Return BOOLEAN_FALSE_NODE if the comparison
3141 always returns false. Return NULL_TREE if it is not always
3142 possible to determine the value of the comparison. Also set
3143 *STRICT_OVERFLOW_P to indicate whether a range with an overflow
3144 infinity was used in the test. */
3147 compare_range_with_value (enum tree_code comp, value_range_t *vr, tree val,
3148 bool *strict_overflow_p)
3150 if (vr->type == VR_VARYING || vr->type == VR_UNDEFINED)
3153 /* Anti-ranges need to be handled separately. */
3154 if (vr->type == VR_ANTI_RANGE)
3156 /* For anti-ranges, the only predicates that we can compute at
3157 compile time are equality and inequality. */
3164 /* ~[VAL_1, VAL_2] OP VAL is known if VAL_1 <= VAL <= VAL_2. */
3165 if (value_inside_range (val, vr) == 1)
3166 return (comp == NE_EXPR) ? boolean_true_node : boolean_false_node;
3171 if (!usable_range_p (vr, strict_overflow_p))
3174 if (comp == EQ_EXPR)
3176 /* EQ_EXPR may only be computed if VR represents exactly
3178 if (compare_values_warnv (vr->min, vr->max, strict_overflow_p) == 0)
3180 int cmp = compare_values_warnv (vr->min, val, strict_overflow_p);
3182 return boolean_true_node;
3183 else if (cmp == -1 || cmp == 1 || cmp == 2)
3184 return boolean_false_node;
3186 else if (compare_values_warnv (val, vr->min, strict_overflow_p) == -1
3187 || compare_values_warnv (vr->max, val, strict_overflow_p) == -1)
3188 return boolean_false_node;
3192 else if (comp == NE_EXPR)
3194 /* If VAL is not inside VR, then they are always different. */
3195 if (compare_values_warnv (vr->max, val, strict_overflow_p) == -1
3196 || compare_values_warnv (vr->min, val, strict_overflow_p) == 1)
3197 return boolean_true_node;
3199 /* If VR represents exactly one value equal to VAL, then return
3201 if (compare_values_warnv (vr->min, vr->max, strict_overflow_p) == 0
3202 && compare_values_warnv (vr->min, val, strict_overflow_p) == 0)
3203 return boolean_false_node;
3205 /* Otherwise, they may or may not be different. */
3208 else if (comp == LT_EXPR || comp == LE_EXPR)
3212 /* If VR is to the left of VAL, return true. */
3213 tst = compare_values_warnv (vr->max, val, strict_overflow_p);
3214 if ((comp == LT_EXPR && tst == -1)
3215 || (comp == LE_EXPR && (tst == -1 || tst == 0)))
3217 if (overflow_infinity_range_p (vr))
3218 *strict_overflow_p = true;
3219 return boolean_true_node;
3222 /* If VR is to the right of VAL, return false. */
3223 tst = compare_values_warnv (vr->min, val, strict_overflow_p);
3224 if ((comp == LT_EXPR && (tst == 0 || tst == 1))
3225 || (comp == LE_EXPR && tst == 1))
3227 if (overflow_infinity_range_p (vr))
3228 *strict_overflow_p = true;
3229 return boolean_false_node;
3232 /* Otherwise, we don't know. */
3235 else if (comp == GT_EXPR || comp == GE_EXPR)
3239 /* If VR is to the right of VAL, return true. */
3240 tst = compare_values_warnv (vr->min, val, strict_overflow_p);
3241 if ((comp == GT_EXPR && tst == 1)
3242 || (comp == GE_EXPR && (tst == 0 || tst == 1)))
3244 if (overflow_infinity_range_p (vr))
3245 *strict_overflow_p = true;
3246 return boolean_true_node;
3249 /* If VR is to the left of VAL, return false. */
3250 tst = compare_values_warnv (vr->max, val, strict_overflow_p);
3251 if ((comp == GT_EXPR && (tst == -1 || tst == 0))
3252 || (comp == GE_EXPR && tst == -1))
3254 if (overflow_infinity_range_p (vr))
3255 *strict_overflow_p = true;
3256 return boolean_false_node;
3259 /* Otherwise, we don't know. */
3267 /* Debugging dumps. */
3269 void dump_value_range (FILE *, value_range_t *);
3270 void debug_value_range (value_range_t *);
3271 void dump_all_value_ranges (FILE *);
3272 void debug_all_value_ranges (void);
3273 void dump_vr_equiv (FILE *, bitmap);
3274 void debug_vr_equiv (bitmap);
3277 /* Dump value range VR to FILE. */
3280 dump_value_range (FILE *file, value_range_t *vr)
3283 fprintf (file, "[]");
3284 else if (vr->type == VR_UNDEFINED)
3285 fprintf (file, "UNDEFINED");
3286 else if (vr->type == VR_RANGE || vr->type == VR_ANTI_RANGE)
3288 tree type = TREE_TYPE (vr->min);
3290 fprintf (file, "%s[", (vr->type == VR_ANTI_RANGE) ? "~" : "");
3292 if (is_negative_overflow_infinity (vr->min))
3293 fprintf (file, "-INF(OVF)");
3294 else if (INTEGRAL_TYPE_P (type)
3295 && !TYPE_UNSIGNED (type)
3296 && vrp_val_is_min (vr->min))
3297 fprintf (file, "-INF");
3299 print_generic_expr (file, vr->min, 0);
3301 fprintf (file, ", ");
3303 if (is_positive_overflow_infinity (vr->max))
3304 fprintf (file, "+INF(OVF)");
3305 else if (INTEGRAL_TYPE_P (type)
3306 && vrp_val_is_max (vr->max))
3307 fprintf (file, "+INF");
3309 print_generic_expr (file, vr->max, 0);
3311 fprintf (file, "]");
3318 fprintf (file, " EQUIVALENCES: { ");
3320 EXECUTE_IF_SET_IN_BITMAP (vr->equiv, 0, i, bi)
3322 print_generic_expr (file, ssa_name (i), 0);
3323 fprintf (file, " ");
3327 fprintf (file, "} (%u elements)", c);
3330 else if (vr->type == VR_VARYING)
3331 fprintf (file, "VARYING");
3333 fprintf (file, "INVALID RANGE");
3337 /* Dump value range VR to stderr. */
3340 debug_value_range (value_range_t *vr)
3342 dump_value_range (stderr, vr);
3343 fprintf (stderr, "\n");
3347 /* Dump value ranges of all SSA_NAMEs to FILE. */
3350 dump_all_value_ranges (FILE *file)
3354 for (i = 0; i < num_ssa_names; i++)
3358 print_generic_expr (file, ssa_name (i), 0);
3359 fprintf (file, ": ");
3360 dump_value_range (file, vr_value[i]);
3361 fprintf (file, "\n");
3365 fprintf (file, "\n");
3369 /* Dump all value ranges to stderr. */
3372 debug_all_value_ranges (void)
3374 dump_all_value_ranges (stderr);
3378 /* Given a COND_EXPR COND of the form 'V OP W', and an SSA name V,
3379 create a new SSA name N and return the assertion assignment
3380 'V = ASSERT_EXPR <V, V OP W>'. */
3383 build_assert_expr_for (tree cond, tree v)
3387 gcc_assert (TREE_CODE (v) == SSA_NAME);
3388 n = duplicate_ssa_name (v, NULL_TREE);
3390 if (COMPARISON_CLASS_P (cond))
3392 tree a = build2 (ASSERT_EXPR, TREE_TYPE (v), v, cond);
3393 assertion = build_gimple_modify_stmt (n, a);
3395 else if (TREE_CODE (cond) == TRUTH_NOT_EXPR)
3397 /* Given !V, build the assignment N = false. */
3398 tree op0 = TREE_OPERAND (cond, 0);
3399 gcc_assert (op0 == v);
3400 assertion = build_gimple_modify_stmt (n, boolean_false_node);
3402 else if (TREE_CODE (cond) == SSA_NAME)
3404 /* Given V, build the assignment N = true. */
3405 gcc_assert (v == cond);
3406 assertion = build_gimple_modify_stmt (n, boolean_true_node);
3411 SSA_NAME_DEF_STMT (n) = assertion;
3413 /* The new ASSERT_EXPR, creates a new SSA name that replaces the
3414 operand of the ASSERT_EXPR. Register the new name and the old one
3415 in the replacement table so that we can fix the SSA web after
3416 adding all the ASSERT_EXPRs. */
3417 register_new_name_mapping (n, v);
3423 /* Return false if EXPR is a predicate expression involving floating
3427 fp_predicate (const_tree expr)
3429 return (COMPARISON_CLASS_P (expr)
3430 && FLOAT_TYPE_P (TREE_TYPE (TREE_OPERAND (expr, 0))));
3434 /* If the range of values taken by OP can be inferred after STMT executes,
3435 return the comparison code (COMP_CODE_P) and value (VAL_P) that
3436 describes the inferred range. Return true if a range could be
3440 infer_value_range (tree stmt, tree op, enum tree_code *comp_code_p, tree *val_p)
3443 *comp_code_p = ERROR_MARK;
3445 /* Do not attempt to infer anything in names that flow through
3447 if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (op))
3450 /* Similarly, don't infer anything from statements that may throw
3452 if (tree_could_throw_p (stmt))
3455 /* If STMT is the last statement of a basic block with no
3456 successors, there is no point inferring anything about any of its
3457 operands. We would not be able to find a proper insertion point
3458 for the assertion, anyway. */
3459 if (stmt_ends_bb_p (stmt) && EDGE_COUNT (bb_for_stmt (stmt)->succs) == 0)
3462 /* We can only assume that a pointer dereference will yield
3463 non-NULL if -fdelete-null-pointer-checks is enabled. */
3464 if (flag_delete_null_pointer_checks && POINTER_TYPE_P (TREE_TYPE (op)))
3466 unsigned num_uses, num_loads, num_stores;
3468 count_uses_and_derefs (op, stmt, &num_uses, &num_loads, &num_stores);
3469 if (num_loads + num_stores > 0)
3471 *val_p = build_int_cst (TREE_TYPE (op), 0);
3472 *comp_code_p = NE_EXPR;
3481 void dump_asserts_for (FILE *, tree);
3482 void debug_asserts_for (tree);
3483 void dump_all_asserts (FILE *);
3484 void debug_all_asserts (void);
3486 /* Dump all the registered assertions for NAME to FILE. */
3489 dump_asserts_for (FILE *file, tree name)
3493 fprintf (file, "Assertions to be inserted for ");
3494 print_generic_expr (file, name, 0);
3495 fprintf (file, "\n");
3497 loc = asserts_for[SSA_NAME_VERSION (name)];
3500 fprintf (file, "\t");
3501 print_generic_expr (file, bsi_stmt (loc->si), 0);
3502 fprintf (file, "\n\tBB #%d", loc->bb->index);
3505 fprintf (file, "\n\tEDGE %d->%d", loc->e->src->index,
3506 loc->e->dest->index);
3507 dump_edge_info (file, loc->e, 0);
3509 fprintf (file, "\n\tPREDICATE: ");
3510 print_generic_expr (file, name, 0);
3511 fprintf (file, " %s ", tree_code_name[(int)loc->comp_code]);
3512 print_generic_expr (file, loc->val, 0);
3513 fprintf (file, "\n\n");
3517 fprintf (file, "\n");
3521 /* Dump all the registered assertions for NAME to stderr. */
3524 debug_asserts_for (tree name)
3526 dump_asserts_for (stderr, name);
3530 /* Dump all the registered assertions for all the names to FILE. */
3533 dump_all_asserts (FILE *file)
3538 fprintf (file, "\nASSERT_EXPRs to be inserted\n\n");
3539 EXECUTE_IF_SET_IN_BITMAP (need_assert_for, 0, i, bi)
3540 dump_asserts_for (file, ssa_name (i));
3541 fprintf (file, "\n");
3545 /* Dump all the registered assertions for all the names to stderr. */
3548 debug_all_asserts (void)
3550 dump_all_asserts (stderr);
3554 /* If NAME doesn't have an ASSERT_EXPR registered for asserting
3555 'EXPR COMP_CODE VAL' at a location that dominates block BB or
3556 E->DEST, then register this location as a possible insertion point
3557 for ASSERT_EXPR <NAME, EXPR COMP_CODE VAL>.
3559 BB, E and SI provide the exact insertion point for the new
3560 ASSERT_EXPR. If BB is NULL, then the ASSERT_EXPR is to be inserted
3561 on edge E. Otherwise, if E is NULL, the ASSERT_EXPR is inserted on
3562 BB. If SI points to a COND_EXPR or a SWITCH_EXPR statement, then E
3563 must not be NULL. */
3566 register_new_assert_for (tree name, tree expr,
3567 enum tree_code comp_code,
3571 block_stmt_iterator si)
3573 assert_locus_t n, loc, last_loc;
3575 basic_block dest_bb;
3577 #if defined ENABLE_CHECKING
3578 gcc_assert (bb == NULL || e == NULL);
3581 gcc_assert (TREE_CODE (bsi_stmt (si)) != COND_EXPR
3582 && TREE_CODE (bsi_stmt (si)) != SWITCH_EXPR);
3585 /* The new assertion A will be inserted at BB or E. We need to
3586 determine if the new location is dominated by a previously
3587 registered location for A. If we are doing an edge insertion,
3588 assume that A will be inserted at E->DEST. Note that this is not
3591 If E is a critical edge, it will be split. But even if E is
3592 split, the new block will dominate the same set of blocks that
3595 The reverse, however, is not true, blocks dominated by E->DEST
3596 will not be dominated by the new block created to split E. So,
3597 if the insertion location is on a critical edge, we will not use
3598 the new location to move another assertion previously registered
3599 at a block dominated by E->DEST. */
3600 dest_bb = (bb) ? bb : e->dest;
3602 /* If NAME already has an ASSERT_EXPR registered for COMP_CODE and
3603 VAL at a block dominating DEST_BB, then we don't need to insert a new
3604 one. Similarly, if the same assertion already exists at a block
3605 dominated by DEST_BB and the new location is not on a critical
3606 edge, then update the existing location for the assertion (i.e.,
3607 move the assertion up in the dominance tree).
3609 Note, this is implemented as a simple linked list because there
3610 should not be more than a handful of assertions registered per
3611 name. If this becomes a performance problem, a table hashed by
3612 COMP_CODE and VAL could be implemented. */
3613 loc = asserts_for[SSA_NAME_VERSION (name)];
3618 if (loc->comp_code == comp_code
3620 || operand_equal_p (loc->val, val, 0))
3621 && (loc->expr == expr
3622 || operand_equal_p (loc->expr, expr, 0)))
3624 /* If the assertion NAME COMP_CODE VAL has already been
3625 registered at a basic block that dominates DEST_BB, then
3626 we don't need to insert the same assertion again. Note
3627 that we don't check strict dominance here to avoid
3628 replicating the same assertion inside the same basic
3629 block more than once (e.g., when a pointer is
3630 dereferenced several times inside a block).
3632 An exception to this rule are edge insertions. If the
3633 new assertion is to be inserted on edge E, then it will
3634 dominate all the other insertions that we may want to
3635 insert in DEST_BB. So, if we are doing an edge
3636 insertion, don't do this dominance check. */
3638 && dominated_by_p (CDI_DOMINATORS, dest_bb, loc->bb))
3641 /* Otherwise, if E is not a critical edge and DEST_BB
3642 dominates the existing location for the assertion, move
3643 the assertion up in the dominance tree by updating its
3644 location information. */
3645 if ((e == NULL || !EDGE_CRITICAL_P (e))
3646 && dominated_by_p (CDI_DOMINATORS, loc->bb, dest_bb))
3655 /* Update the last node of the list and move to the next one. */
3660 /* If we didn't find an assertion already registered for
3661 NAME COMP_CODE VAL, add a new one at the end of the list of
3662 assertions associated with NAME. */
3663 n = XNEW (struct assert_locus_d);
3667 n->comp_code = comp_code;
3675 asserts_for[SSA_NAME_VERSION (name)] = n;
3677 bitmap_set_bit (need_assert_for, SSA_NAME_VERSION (name));
3680 /* (COND_OP0 COND_CODE COND_OP1) is a predicate which uses NAME.
3681 Extract a suitable test code and value and store them into *CODE_P and
3682 *VAL_P so the predicate is normalized to NAME *CODE_P *VAL_P.
3684 If no extraction was possible, return FALSE, otherwise return TRUE.
3686 If INVERT is true, then we invert the result stored into *CODE_P. */
3689 extract_code_and_val_from_cond_with_ops (tree name, enum tree_code cond_code,
3690 tree cond_op0, tree cond_op1,
3691 bool invert, enum tree_code *code_p,
3694 enum tree_code comp_code;
3697 /* Otherwise, we have a comparison of the form NAME COMP VAL
3698 or VAL COMP NAME. */
3699 if (name == cond_op1)
3701 /* If the predicate is of the form VAL COMP NAME, flip
3702 COMP around because we need to register NAME as the
3703 first operand in the predicate. */
3704 comp_code = swap_tree_comparison (cond_code);
3709 /* The comparison is of the form NAME COMP VAL, so the
3710 comparison code remains unchanged. */
3711 comp_code = cond_code;
3715 /* Invert the comparison code as necessary. */
3717 comp_code = invert_tree_comparison (comp_code, 0);
3719 /* VRP does not handle float types. */
3720 if (SCALAR_FLOAT_TYPE_P (TREE_TYPE (val)))
3723 /* Do not register always-false predicates.
3724 FIXME: this works around a limitation in fold() when dealing with
3725 enumerations. Given 'enum { N1, N2 } x;', fold will not
3726 fold 'if (x > N2)' to 'if (0)'. */
3727 if ((comp_code == GT_EXPR || comp_code == LT_EXPR)
3728 && INTEGRAL_TYPE_P (TREE_TYPE (val)))
3730 tree min = TYPE_MIN_VALUE (TREE_TYPE (val));
3731 tree max = TYPE_MAX_VALUE (TREE_TYPE (val));
3733 if (comp_code == GT_EXPR
3735 || compare_values (val, max) == 0))
3738 if (comp_code == LT_EXPR
3740 || compare_values (val, min) == 0))
3743 *code_p = comp_code;
3748 /* Try to register an edge assertion for SSA name NAME on edge E for
3749 the condition COND contributing to the conditional jump pointed to by BSI.
3750 Invert the condition COND if INVERT is true.
3751 Return true if an assertion for NAME could be registered. */
3754 register_edge_assert_for_2 (tree name, edge e, block_stmt_iterator bsi,
3755 enum tree_code cond_code,
3756 tree cond_op0, tree cond_op1, bool invert)
3759 enum tree_code comp_code;
3760 bool retval = false;
3762 if (!extract_code_and_val_from_cond_with_ops (name, cond_code,
3765 invert, &comp_code, &val))
3768 /* Only register an ASSERT_EXPR if NAME was found in the sub-graph
3769 reachable from E. */
3770 if (TEST_BIT (found_in_subgraph, SSA_NAME_VERSION (name))
3771 && !has_single_use (name))
3773 register_new_assert_for (name, name, comp_code, val, NULL, e, bsi);
3777 /* In the case of NAME <= CST and NAME being defined as
3778 NAME = (unsigned) NAME2 + CST2 we can assert NAME2 >= -CST2
3779 and NAME2 <= CST - CST2. We can do the same for NAME > CST.
3780 This catches range and anti-range tests. */
3781 if ((comp_code == LE_EXPR
3782 || comp_code == GT_EXPR)
3783 && TREE_CODE (val) == INTEGER_CST
3784 && TYPE_UNSIGNED (TREE_TYPE (val)))
3786 tree def_stmt = SSA_NAME_DEF_STMT (name);
3787 tree cst2 = NULL_TREE, name2 = NULL_TREE, name3 = NULL_TREE;
3789 /* Extract CST2 from the (optional) addition. */
3790 if (TREE_CODE (def_stmt) == GIMPLE_MODIFY_STMT
3791 && TREE_CODE (GIMPLE_STMT_OPERAND (def_stmt, 1)) == PLUS_EXPR)
3793 name2 = TREE_OPERAND (GIMPLE_STMT_OPERAND (def_stmt, 1), 0);
3794 cst2 = TREE_OPERAND (GIMPLE_STMT_OPERAND (def_stmt, 1), 1);
3795 if (TREE_CODE (name2) == SSA_NAME
3796 && TREE_CODE (cst2) == INTEGER_CST)
3797 def_stmt = SSA_NAME_DEF_STMT (name2);
3800 /* Extract NAME2 from the (optional) sign-changing cast. */
3801 if (TREE_CODE (def_stmt) == GIMPLE_MODIFY_STMT
3802 && (TREE_CODE (GIMPLE_STMT_OPERAND (def_stmt, 1)) == NOP_EXPR
3803 || TREE_CODE (GIMPLE_STMT_OPERAND (def_stmt, 1)) == CONVERT_EXPR))
3805 tree rhs = GIMPLE_STMT_OPERAND (def_stmt, 1);
3806 if ((TREE_CODE (rhs) == NOP_EXPR
3807 || TREE_CODE (rhs) == CONVERT_EXPR)
3808 && ! TYPE_UNSIGNED (TREE_TYPE (TREE_OPERAND (rhs, 0)))
3809 && (TYPE_PRECISION (TREE_TYPE (rhs))
3810 == TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (rhs, 0)))))
3811 name3 = TREE_OPERAND (GIMPLE_STMT_OPERAND (def_stmt, 1), 0);
3814 /* If name3 is used later, create an ASSERT_EXPR for it. */
3815 if (name3 != NULL_TREE
3816 && TREE_CODE (name3) == SSA_NAME
3817 && (cst2 == NULL_TREE
3818 || TREE_CODE (cst2) == INTEGER_CST)
3819 && INTEGRAL_TYPE_P (TREE_TYPE (name3))
3820 && TEST_BIT (found_in_subgraph, SSA_NAME_VERSION (name3))
3821 && !has_single_use (name3))
3825 /* Build an expression for the range test. */
3826 tmp = build1 (NOP_EXPR, TREE_TYPE (name), name3);
3827 if (cst2 != NULL_TREE)
3828 tmp = build2 (PLUS_EXPR, TREE_TYPE (name), tmp, cst2);
3832 fprintf (dump_file, "Adding assert for ");
3833 print_generic_expr (dump_file, name3, 0);
3834 fprintf (dump_file, " from ");
3835 print_generic_expr (dump_file, tmp, 0);
3836 fprintf (dump_file, "\n");
3839 register_new_assert_for (name3, tmp, comp_code, val, NULL, e, bsi);
3844 /* If name2 is used later, create an ASSERT_EXPR for it. */
3845 if (name2 != NULL_TREE
3846 && TREE_CODE (name2) == SSA_NAME
3847 && TREE_CODE (cst2) == INTEGER_CST
3848 && INTEGRAL_TYPE_P (TREE_TYPE (name2))
3849 && TEST_BIT (found_in_subgraph, SSA_NAME_VERSION (name2))
3850 && !has_single_use (name2))
3854 /* Build an expression for the range test. */
3856 if (TREE_TYPE (name) != TREE_TYPE (name2))
3857 tmp = build1 (NOP_EXPR, TREE_TYPE (name), tmp);
3858 if (cst2 != NULL_TREE)
3859 tmp = build2 (PLUS_EXPR, TREE_TYPE (name), tmp, cst2);
3863 fprintf (dump_file, "Adding assert for ");
3864 print_generic_expr (dump_file, name2, 0);
3865 fprintf (dump_file, " from ");
3866 print_generic_expr (dump_file, tmp, 0);
3867 fprintf (dump_file, "\n");
3870 register_new_assert_for (name2, tmp, comp_code, val, NULL, e, bsi);
3879 /* OP is an operand of a truth value expression which is known to have
3880 a particular value. Register any asserts for OP and for any
3881 operands in OP's defining statement.
3883 If CODE is EQ_EXPR, then we want to register OP is zero (false),
3884 if CODE is NE_EXPR, then we want to register OP is nonzero (true). */
3887 register_edge_assert_for_1 (tree op, enum tree_code code,
3888 edge e, block_stmt_iterator bsi)
3890 bool retval = false;
3891 tree op_def, rhs, val;
3892 enum tree_code rhs_code;
3894 /* We only care about SSA_NAMEs. */
3895 if (TREE_CODE (op) != SSA_NAME)
3898 /* We know that OP will have a zero or nonzero value. If OP is used
3899 more than once go ahead and register an assert for OP.
3901 The FOUND_IN_SUBGRAPH support is not helpful in this situation as
3902 it will always be set for OP (because OP is used in a COND_EXPR in
3904 if (!has_single_use (op))
3906 val = build_int_cst (TREE_TYPE (op), 0);
3907 register_new_assert_for (op, op, code, val, NULL, e, bsi);
3911 /* Now look at how OP is set. If it's set from a comparison,
3912 a truth operation or some bit operations, then we may be able
3913 to register information about the operands of that assignment. */
3914 op_def = SSA_NAME_DEF_STMT (op);
3915 if (TREE_CODE (op_def) != GIMPLE_MODIFY_STMT)
3918 rhs = GIMPLE_STMT_OPERAND (op_def, 1);
3919 rhs_code = TREE_CODE (rhs);
3921 if (COMPARISON_CLASS_P (rhs))
3923 bool invert = (code == EQ_EXPR ? true : false);
3924 tree op0 = TREE_OPERAND (rhs, 0);
3925 tree op1 = TREE_OPERAND (rhs, 1);
3927 if (TREE_CODE (op0) == SSA_NAME)
3928 retval |= register_edge_assert_for_2 (op0, e, bsi, rhs_code, op0, op1,
3930 if (TREE_CODE (op1) == SSA_NAME)
3931 retval |= register_edge_assert_for_2 (op1, e, bsi, rhs_code, op0, op1,
3934 else if ((code == NE_EXPR
3935 && (TREE_CODE (rhs) == TRUTH_AND_EXPR
3936 || TREE_CODE (rhs) == BIT_AND_EXPR))
3938 && (TREE_CODE (rhs) == TRUTH_OR_EXPR
3939 || TREE_CODE (rhs) == BIT_IOR_EXPR)))
3941 /* Recurse on each operand. */
3942 retval |= register_edge_assert_for_1 (TREE_OPERAND (rhs, 0),
3944 retval |= register_edge_assert_for_1 (TREE_OPERAND (rhs, 1),
3947 else if (TREE_CODE (rhs) == TRUTH_NOT_EXPR)
3949 /* Recurse, flipping CODE. */
3950 code = invert_tree_comparison (code, false);
3951 retval |= register_edge_assert_for_1 (TREE_OPERAND (rhs, 0),
3954 else if (TREE_CODE (rhs) == SSA_NAME)
3956 /* Recurse through the copy. */
3957 retval |= register_edge_assert_for_1 (rhs, code, e, bsi);
3959 else if (TREE_CODE (rhs) == NOP_EXPR
3960 || TREE_CODE (rhs) == CONVERT_EXPR
3961 || TREE_CODE (rhs) == NON_LVALUE_EXPR)
3963 /* Recurse through the type conversion. */
3964 retval |= register_edge_assert_for_1 (TREE_OPERAND (rhs, 0),
3971 /* Try to register an edge assertion for SSA name NAME on edge E for
3972 the condition COND contributing to the conditional jump pointed to by SI.
3973 Return true if an assertion for NAME could be registered. */
3976 register_edge_assert_for (tree name, edge e, block_stmt_iterator si,
3977 enum tree_code cond_code, tree cond_op0,
3981 enum tree_code comp_code;
3982 bool retval = false;
3983 bool is_else_edge = (e->flags & EDGE_FALSE_VALUE) != 0;
3985 /* Do not attempt to infer anything in names that flow through
3987 if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (name))
3990 if (!extract_code_and_val_from_cond_with_ops (name, cond_code,
3996 /* Register ASSERT_EXPRs for name. */
3997 retval |= register_edge_assert_for_2 (name, e, si, cond_code, cond_op0,
3998 cond_op1, is_else_edge);
4001 /* If COND is effectively an equality test of an SSA_NAME against
4002 the value zero or one, then we may be able to assert values
4003 for SSA_NAMEs which flow into COND. */
4005 /* In the case of NAME == 1 or NAME != 0, for TRUTH_AND_EXPR defining
4006 statement of NAME we can assert both operands of the TRUTH_AND_EXPR
4007 have nonzero value. */
4008 if (((comp_code == EQ_EXPR && integer_onep (val))
4009 || (comp_code == NE_EXPR && integer_zerop (val))))
4011 tree def_stmt = SSA_NAME_DEF_STMT (name);
4013 if (TREE_CODE (def_stmt) == GIMPLE_MODIFY_STMT
4014 && (TREE_CODE (GIMPLE_STMT_OPERAND (def_stmt, 1)) == TRUTH_AND_EXPR
4015 || TREE_CODE (GIMPLE_STMT_OPERAND (def_stmt, 1)) == BIT_AND_EXPR))
4017 tree op0 = TREE_OPERAND (GIMPLE_STMT_OPERAND (def_stmt, 1), 0);
4018 tree op1 = TREE_OPERAND (GIMPLE_STMT_OPERAND (def_stmt, 1), 1);
4019 retval |= register_edge_assert_for_1 (op0, NE_EXPR, e, si);
4020 retval |= register_edge_assert_for_1 (op1, NE_EXPR, e, si);
4024 /* In the case of NAME == 0 or NAME != 1, for TRUTH_OR_EXPR defining
4025 statement of NAME we can assert both operands of the TRUTH_OR_EXPR
4027 if (((comp_code == EQ_EXPR && integer_zerop (val))
4028 || (comp_code == NE_EXPR && integer_onep (val))))
4030 tree def_stmt = SSA_NAME_DEF_STMT (name);
4032 if (TREE_CODE (def_stmt) == GIMPLE_MODIFY_STMT
4033 && (TREE_CODE (GIMPLE_STMT_OPERAND (def_stmt, 1)) == TRUTH_OR_EXPR
4034 /* For BIT_IOR_EXPR only if NAME == 0 both operands have
4035 necessarily zero value. */
4036 || (comp_code == EQ_EXPR
4037 && (TREE_CODE (GIMPLE_STMT_OPERAND (def_stmt, 1))
4040 tree op0 = TREE_OPERAND (GIMPLE_STMT_OPERAND (def_stmt, 1), 0);
4041 tree op1 = TREE_OPERAND (GIMPLE_STMT_OPERAND (def_stmt, 1), 1);
4042 retval |= register_edge_assert_for_1 (op0, EQ_EXPR, e, si);
4043 retval |= register_edge_assert_for_1 (op1, EQ_EXPR, e, si);
4051 static bool find_assert_locations (basic_block bb);
4053 /* Determine whether the outgoing edges of BB should receive an
4054 ASSERT_EXPR for each of the operands of BB's LAST statement.
4055 The last statement of BB must be a COND_EXPR.
4057 If any of the sub-graphs rooted at BB have an interesting use of
4058 the predicate operands, an assert location node is added to the
4059 list of assertions for the corresponding operands. */
4062 find_conditional_asserts (basic_block bb, tree last)
4065 block_stmt_iterator bsi;
4071 need_assert = false;
4072 bsi = bsi_for_stmt (last);
4074 /* Look for uses of the operands in each of the sub-graphs
4075 rooted at BB. We need to check each of the outgoing edges
4076 separately, so that we know what kind of ASSERT_EXPR to
4078 FOR_EACH_EDGE (e, ei, bb->succs)
4083 /* Remove the COND_EXPR operands from the FOUND_IN_SUBGRAPH bitmap.
4084 Otherwise, when we finish traversing each of the sub-graphs, we
4085 won't know whether the variables were found in the sub-graphs or
4086 if they had been found in a block upstream from BB.
4088 This is actually a bad idea is some cases, particularly jump
4089 threading. Consider a CFG like the following:
4099 Assume that one or more operands in the conditional at the
4100 end of block 0 are used in a conditional in block 2, but not
4101 anywhere in block 1. In this case we will not insert any
4102 assert statements in block 1, which may cause us to miss
4103 opportunities to optimize, particularly for jump threading. */
4104 FOR_EACH_SSA_TREE_OPERAND (op, last, iter, SSA_OP_USE)
4105 RESET_BIT (found_in_subgraph, SSA_NAME_VERSION (op));
4107 /* Traverse the strictly dominated sub-graph rooted at E->DEST
4108 to determine if any of the operands in the conditional
4109 predicate are used. */
4110 need_assert |= find_assert_locations (e->dest);
4112 /* Register the necessary assertions for each operand in the
4113 conditional predicate. */
4114 FOR_EACH_SSA_TREE_OPERAND (op, last, iter, SSA_OP_USE)
4116 tree cond = COND_EXPR_COND (last);
4118 need_assert |= register_edge_assert_for (op, e, bsi,
4120 TREE_OPERAND (cond, 0),
4121 TREE_OPERAND (cond, 1));
4123 need_assert |= register_edge_assert_for (op, e, bsi, EQ_EXPR, op,
4128 /* Finally, indicate that we have found the operands in the
4130 FOR_EACH_SSA_TREE_OPERAND (op, last, iter, SSA_OP_USE)
4131 SET_BIT (found_in_subgraph, SSA_NAME_VERSION (op));
4136 /* Compare two case labels sorting first by the destination label uid
4137 and then by the case value. */
4140 compare_case_labels (const void *p1, const void *p2)
4142 const_tree const case1 = *(const_tree const*)p1;
4143 const_tree const case2 = *(const_tree const*)p2;
4144 unsigned int uid1 = DECL_UID (CASE_LABEL (case1));
4145 unsigned int uid2 = DECL_UID (CASE_LABEL (case2));
4149 else if (uid1 == uid2)
4151 /* Make sure the default label is first in a group. */
4152 if (!CASE_LOW (case1))
4154 else if (!CASE_LOW (case2))
4157 return tree_int_cst_compare (CASE_LOW (case1), CASE_LOW (case2));
4163 /* Determine whether the outgoing edges of BB should receive an
4164 ASSERT_EXPR for each of the operands of BB's LAST statement.
4165 The last statement of BB must be a SWITCH_EXPR.
4167 If any of the sub-graphs rooted at BB have an interesting use of
4168 the predicate operands, an assert location node is added to the
4169 list of assertions for the corresponding operands. */
4172 find_switch_asserts (basic_block bb, tree last)
4175 block_stmt_iterator bsi;
4178 tree vec = SWITCH_LABELS (last), vec2;
4179 size_t n = TREE_VEC_LENGTH (vec);
4182 need_assert = false;
4183 bsi = bsi_for_stmt (last);
4184 op = TREE_OPERAND (last, 0);
4185 if (TREE_CODE (op) != SSA_NAME)
4188 /* Build a vector of case labels sorted by destination label. */
4189 vec2 = make_tree_vec (n);
4190 for (idx = 0; idx < n; ++idx)
4191 TREE_VEC_ELT (vec2, idx) = TREE_VEC_ELT (vec, idx);
4192 qsort (&TREE_VEC_ELT (vec2, 0), n, sizeof (tree), compare_case_labels);
4194 for (idx = 0; idx < n; ++idx)
4197 tree cl = TREE_VEC_ELT (vec2, idx);
4199 min = CASE_LOW (cl);
4200 max = CASE_HIGH (cl);
4202 /* If there are multiple case labels with the same destination
4203 we need to combine them to a single value range for the edge. */
4205 && CASE_LABEL (cl) == CASE_LABEL (TREE_VEC_ELT (vec2, idx + 1)))
4207 /* Skip labels until the last of the group. */
4211 && CASE_LABEL (cl) == CASE_LABEL (TREE_VEC_ELT (vec2, idx)));
4214 /* Pick up the maximum of the case label range. */
4215 if (CASE_HIGH (TREE_VEC_ELT (vec2, idx)))
4216 max = CASE_HIGH (TREE_VEC_ELT (vec2, idx));
4218 max = CASE_LOW (TREE_VEC_ELT (vec2, idx));
4221 /* Nothing to do if the range includes the default label until we
4222 can register anti-ranges. */
4223 if (min == NULL_TREE)
4226 /* Find the edge to register the assert expr on. */
4227 e = find_edge (bb, label_to_block (CASE_LABEL (cl)));
4229 /* Remove the SWITCH_EXPR operand from the FOUND_IN_SUBGRAPH bitmap.
4230 Otherwise, when we finish traversing each of the sub-graphs, we
4231 won't know whether the variables were found in the sub-graphs or
4232 if they had been found in a block upstream from BB. */
4233 RESET_BIT (found_in_subgraph, SSA_NAME_VERSION (op));
4235 /* Traverse the strictly dominated sub-graph rooted at E->DEST
4236 to determine if any of the operands in the conditional
4237 predicate are used. */
4239 need_assert |= find_assert_locations (e->dest);
4241 /* Register the necessary assertions for the operand in the
4243 need_assert |= register_edge_assert_for (op, e, bsi,
4244 max ? GE_EXPR : EQ_EXPR,
4246 fold_convert (TREE_TYPE (op),
4250 need_assert |= register_edge_assert_for (op, e, bsi, LE_EXPR,
4252 fold_convert (TREE_TYPE (op),
4257 /* Finally, indicate that we have found the operand in the
4259 SET_BIT (found_in_subgraph, SSA_NAME_VERSION (op));
4265 /* Traverse all the statements in block BB looking for statements that
4266 may generate useful assertions for the SSA names in their operand.
4267 If a statement produces a useful assertion A for name N_i, then the
4268 list of assertions already generated for N_i is scanned to
4269 determine if A is actually needed.
4271 If N_i already had the assertion A at a location dominating the
4272 current location, then nothing needs to be done. Otherwise, the
4273 new location for A is recorded instead.
4275 1- For every statement S in BB, all the variables used by S are
4276 added to bitmap FOUND_IN_SUBGRAPH.
4278 2- If statement S uses an operand N in a way that exposes a known
4279 value range for N, then if N was not already generated by an
4280 ASSERT_EXPR, create a new assert location for N. For instance,
4281 if N is a pointer and the statement dereferences it, we can
4282 assume that N is not NULL.
4284 3- COND_EXPRs are a special case of #2. We can derive range
4285 information from the predicate but need to insert different
4286 ASSERT_EXPRs for each of the sub-graphs rooted at the
4287 conditional block. If the last statement of BB is a conditional
4288 expression of the form 'X op Y', then
4290 a) Remove X and Y from the set FOUND_IN_SUBGRAPH.
4292 b) If the conditional is the only entry point to the sub-graph
4293 corresponding to the THEN_CLAUSE, recurse into it. On
4294 return, if X and/or Y are marked in FOUND_IN_SUBGRAPH, then
4295 an ASSERT_EXPR is added for the corresponding variable.
4297 c) Repeat step (b) on the ELSE_CLAUSE.
4299 d) Mark X and Y in FOUND_IN_SUBGRAPH.
4308 In this case, an assertion on the THEN clause is useful to
4309 determine that 'a' is always 9 on that edge. However, an assertion
4310 on the ELSE clause would be unnecessary.
4312 4- If BB does not end in a conditional expression, then we recurse
4313 into BB's dominator children.
4315 At the end of the recursive traversal, every SSA name will have a
4316 list of locations where ASSERT_EXPRs should be added. When a new
4317 location for name N is found, it is registered by calling
4318 register_new_assert_for. That function keeps track of all the
4319 registered assertions to prevent adding unnecessary assertions.
4320 For instance, if a pointer P_4 is dereferenced more than once in a
4321 dominator tree, only the location dominating all the dereference of
4322 P_4 will receive an ASSERT_EXPR.
4324 If this function returns true, then it means that there are names
4325 for which we need to generate ASSERT_EXPRs. Those assertions are
4326 inserted by process_assert_insertions. */
4329 find_assert_locations (basic_block bb)
4331 block_stmt_iterator si;
4336 if (TEST_BIT (blocks_visited, bb->index))
4339 SET_BIT (blocks_visited, bb->index);
4341 need_assert = false;
4343 /* Traverse all PHI nodes in BB marking used operands. */
4344 for (phi = phi_nodes (bb); phi; phi = PHI_CHAIN (phi))
4346 use_operand_p arg_p;
4349 FOR_EACH_PHI_ARG (arg_p, phi, i, SSA_OP_USE)
4351 tree arg = USE_FROM_PTR (arg_p);
4352 if (TREE_CODE (arg) == SSA_NAME)
4354 gcc_assert (is_gimple_reg (PHI_RESULT (phi)));
4355 SET_BIT (found_in_subgraph, SSA_NAME_VERSION (arg));
4360 /* Traverse all the statements in BB marking used names and looking
4361 for statements that may infer assertions for their used operands. */
4363 for (si = bsi_start (bb); !bsi_end_p (si); bsi_next (&si))
4368 stmt = bsi_stmt (si);
4370 /* See if we can derive an assertion for any of STMT's operands. */
4371 FOR_EACH_SSA_TREE_OPERAND (op, stmt, i, SSA_OP_USE)
4374 enum tree_code comp_code;
4376 /* Mark OP in bitmap FOUND_IN_SUBGRAPH. If STMT is inside
4377 the sub-graph of a conditional block, when we return from
4378 this recursive walk, our parent will use the
4379 FOUND_IN_SUBGRAPH bitset to determine if one of the
4380 operands it was looking for was present in the sub-graph. */
4381 SET_BIT (found_in_subgraph, SSA_NAME_VERSION (op));
4383 /* If OP is used in such a way that we can infer a value
4384 range for it, and we don't find a previous assertion for
4385 it, create a new assertion location node for OP. */
4386 if (infer_value_range (stmt, op, &comp_code, &value))
4388 /* If we are able to infer a nonzero value range for OP,
4389 then walk backwards through the use-def chain to see if OP
4390 was set via a typecast.
4392 If so, then we can also infer a nonzero value range
4393 for the operand of the NOP_EXPR. */
4394 if (comp_code == NE_EXPR && integer_zerop (value))
4397 tree def_stmt = SSA_NAME_DEF_STMT (t);
4399 while (TREE_CODE (def_stmt) == GIMPLE_MODIFY_STMT
4401 (GIMPLE_STMT_OPERAND (def_stmt, 1)) == NOP_EXPR
4403 (TREE_OPERAND (GIMPLE_STMT_OPERAND (def_stmt, 1),
4406 (TREE_TYPE (TREE_OPERAND
4407 (GIMPLE_STMT_OPERAND (def_stmt,
4410 t = TREE_OPERAND (GIMPLE_STMT_OPERAND (def_stmt, 1), 0);
4411 def_stmt = SSA_NAME_DEF_STMT (t);
4413 /* Note we want to register the assert for the
4414 operand of the NOP_EXPR after SI, not after the
4416 if (! has_single_use (t))
4418 register_new_assert_for (t, t, comp_code, value,
4425 /* If OP is used only once, namely in this STMT, don't
4426 bother creating an ASSERT_EXPR for it. Such an
4427 ASSERT_EXPR would do nothing but increase compile time. */
4428 if (!has_single_use (op))
4430 register_new_assert_for (op, op, comp_code, value,
4437 /* Remember the last statement of the block. */
4441 /* If BB's last statement is a conditional expression
4442 involving integer operands, recurse into each of the sub-graphs
4443 rooted at BB to determine if we need to add ASSERT_EXPRs. */
4445 && TREE_CODE (last) == COND_EXPR
4446 && !fp_predicate (COND_EXPR_COND (last))
4447 && !ZERO_SSA_OPERANDS (last, SSA_OP_USE))
4448 need_assert |= find_conditional_asserts (bb, last);
4451 && TREE_CODE (last) == SWITCH_EXPR
4452 && !ZERO_SSA_OPERANDS (last, SSA_OP_USE))
4453 need_assert |= find_switch_asserts (bb, last);
4455 /* Recurse into the dominator children of BB. */
4456 for (son = first_dom_son (CDI_DOMINATORS, bb);
4458 son = next_dom_son (CDI_DOMINATORS, son))
4459 need_assert |= find_assert_locations (son);
4465 /* Create an ASSERT_EXPR for NAME and insert it in the location
4466 indicated by LOC. Return true if we made any edge insertions. */
4469 process_assert_insertions_for (tree name, assert_locus_t loc)
4471 /* Build the comparison expression NAME_i COMP_CODE VAL. */
4472 tree stmt, cond, assert_expr;
4476 cond = build2 (loc->comp_code, boolean_type_node, loc->expr, loc->val);
4477 assert_expr = build_assert_expr_for (cond, name);
4481 /* We have been asked to insert the assertion on an edge. This
4482 is used only by COND_EXPR and SWITCH_EXPR assertions. */
4483 #if defined ENABLE_CHECKING
4484 gcc_assert (TREE_CODE (bsi_stmt (loc->si)) == COND_EXPR
4485 || TREE_CODE (bsi_stmt (loc->si)) == SWITCH_EXPR);
4488 bsi_insert_on_edge (loc->e, assert_expr);
4492 /* Otherwise, we can insert right after LOC->SI iff the
4493 statement must not be the last statement in the block. */
4494 stmt = bsi_stmt (loc->si);
4495 if (!stmt_ends_bb_p (stmt))
4497 bsi_insert_after (&loc->si, assert_expr, BSI_SAME_STMT);
4501 /* If STMT must be the last statement in BB, we can only insert new
4502 assertions on the non-abnormal edge out of BB. Note that since
4503 STMT is not control flow, there may only be one non-abnormal edge
4505 FOR_EACH_EDGE (e, ei, loc->bb->succs)
4506 if (!(e->flags & EDGE_ABNORMAL))
4508 bsi_insert_on_edge (e, assert_expr);
4516 /* Process all the insertions registered for every name N_i registered
4517 in NEED_ASSERT_FOR. The list of assertions to be inserted are
4518 found in ASSERTS_FOR[i]. */
4521 process_assert_insertions (void)
4525 bool update_edges_p = false;
4526 int num_asserts = 0;
4528 if (dump_file && (dump_flags & TDF_DETAILS))
4529 dump_all_asserts (dump_file);
4531 EXECUTE_IF_SET_IN_BITMAP (need_assert_for, 0, i, bi)
4533 assert_locus_t loc = asserts_for[i];
4538 assert_locus_t next = loc->next;
4539 update_edges_p |= process_assert_insertions_for (ssa_name (i), loc);
4547 bsi_commit_edge_inserts ();
4549 if (dump_file && (dump_flags & TDF_STATS))
4550 fprintf (dump_file, "\nNumber of ASSERT_EXPR expressions inserted: %d\n\n",
4555 /* Traverse the flowgraph looking for conditional jumps to insert range
4556 expressions. These range expressions are meant to provide information
4557 to optimizations that need to reason in terms of value ranges. They
4558 will not be expanded into RTL. For instance, given:
4567 this pass will transform the code into:
4573 x = ASSERT_EXPR <x, x < y>
4578 y = ASSERT_EXPR <y, x <= y>
4582 The idea is that once copy and constant propagation have run, other
4583 optimizations will be able to determine what ranges of values can 'x'
4584 take in different paths of the code, simply by checking the reaching
4585 definition of 'x'. */
4588 insert_range_assertions (void)
4594 found_in_subgraph = sbitmap_alloc (num_ssa_names);
4595 sbitmap_zero (found_in_subgraph);
4597 blocks_visited = sbitmap_alloc (last_basic_block);
4598 sbitmap_zero (blocks_visited);
4600 need_assert_for = BITMAP_ALLOC (NULL);
4601 asserts_for = XCNEWVEC (assert_locus_t, num_ssa_names);
4603 calculate_dominance_info (CDI_DOMINATORS);
4605 update_ssa_p = false;
4606 FOR_EACH_EDGE (e, ei, ENTRY_BLOCK_PTR->succs)
4607 if (find_assert_locations (e->dest))
4608 update_ssa_p = true;
4612 process_assert_insertions ();
4613 update_ssa (TODO_update_ssa_no_phi);
4616 if (dump_file && (dump_flags & TDF_DETAILS))
4618 fprintf (dump_file, "\nSSA form after inserting ASSERT_EXPRs\n");
4619 dump_function_to_file (current_function_decl, dump_file, dump_flags);
4622 sbitmap_free (found_in_subgraph);
4624 BITMAP_FREE (need_assert_for);
4627 /* Checks one ARRAY_REF in REF, located at LOCUS. Ignores flexible arrays
4628 and "struct" hacks. If VRP can determine that the
4629 array subscript is a constant, check if it is outside valid
4630 range. If the array subscript is a RANGE, warn if it is
4631 non-overlapping with valid range.
4632 IGNORE_OFF_BY_ONE is true if the ARRAY_REF is inside a ADDR_EXPR. */
4635 check_array_ref (tree ref, location_t* locus, bool ignore_off_by_one)
4637 value_range_t* vr = NULL;
4638 tree low_sub, up_sub;
4639 tree low_bound, up_bound = array_ref_up_bound (ref);
4641 low_sub = up_sub = TREE_OPERAND (ref, 1);
4643 if (!up_bound || TREE_NO_WARNING (ref)
4644 || TREE_CODE (up_bound) != INTEGER_CST
4645 /* Can not check flexible arrays. */
4646 || (TYPE_SIZE (TREE_TYPE (ref)) == NULL_TREE
4647 && TYPE_DOMAIN (TREE_TYPE (ref)) != NULL_TREE
4648 && TYPE_MAX_VALUE (TYPE_DOMAIN (TREE_TYPE (ref))) == NULL_TREE)
4649 /* Accesses after the end of arrays of size 0 (gcc
4650 extension) and 1 are likely intentional ("struct
4652 || compare_tree_int (up_bound, 1) <= 0)
4655 low_bound = array_ref_low_bound (ref);
4657 if (TREE_CODE (low_sub) == SSA_NAME)
4659 vr = get_value_range (low_sub);
4660 if (vr->type == VR_RANGE || vr->type == VR_ANTI_RANGE)
4662 low_sub = vr->type == VR_RANGE ? vr->max : vr->min;
4663 up_sub = vr->type == VR_RANGE ? vr->min : vr->max;
4667 if (vr && vr->type == VR_ANTI_RANGE)
4669 if (TREE_CODE (up_sub) == INTEGER_CST
4670 && tree_int_cst_lt (up_bound, up_sub)
4671 && TREE_CODE (low_sub) == INTEGER_CST
4672 && tree_int_cst_lt (low_sub, low_bound))
4674 warning (OPT_Warray_bounds,
4675 "%Harray subscript is outside array bounds", locus);
4676 TREE_NO_WARNING (ref) = 1;
4679 else if (TREE_CODE (up_sub) == INTEGER_CST
4680 && tree_int_cst_lt (up_bound, up_sub)
4681 && !tree_int_cst_equal (up_bound, up_sub)
4682 && (!ignore_off_by_one
4683 || !tree_int_cst_equal (int_const_binop (PLUS_EXPR,
4689 warning (OPT_Warray_bounds, "%Harray subscript is above array bounds",
4691 TREE_NO_WARNING (ref) = 1;
4693 else if (TREE_CODE (low_sub) == INTEGER_CST
4694 && tree_int_cst_lt (low_sub, low_bound))
4696 warning (OPT_Warray_bounds, "%Harray subscript is below array bounds",
4698 TREE_NO_WARNING (ref) = 1;
4702 /* Searches if the expr T, located at LOCATION computes
4703 address of an ARRAY_REF, and call check_array_ref on it. */
4706 search_for_addr_array(tree t, location_t* location)
4708 while (TREE_CODE (t) == SSA_NAME)
4710 t = SSA_NAME_DEF_STMT (t);
4711 if (TREE_CODE (t) != GIMPLE_MODIFY_STMT)
4713 t = GIMPLE_STMT_OPERAND (t, 1);
4717 /* We are only interested in addresses of ARRAY_REF's. */
4718 if (TREE_CODE (t) != ADDR_EXPR)
4721 /* Check each ARRAY_REFs in the reference chain. */
4724 if (TREE_CODE (t) == ARRAY_REF)
4725 check_array_ref (t, location, true /*ignore_off_by_one*/);
4727 t = TREE_OPERAND(t,0);
4729 while (handled_component_p (t));
4732 /* walk_tree() callback that checks if *TP is
4733 an ARRAY_REF inside an ADDR_EXPR (in which an array
4734 subscript one outside the valid range is allowed). Call
4735 check_array_ref for each ARRAY_REF found. The location is
4739 check_array_bounds (tree *tp, int *walk_subtree, void *data)
4742 tree stmt = (tree)data;
4743 location_t *location = EXPR_LOCUS (stmt);
4745 if (!EXPR_HAS_LOCATION (stmt))
4747 *walk_subtree = FALSE;
4751 *walk_subtree = TRUE;
4753 if (TREE_CODE (t) == ARRAY_REF)
4754 check_array_ref (t, location, false /*ignore_off_by_one*/);
4756 if (TREE_CODE (t) == INDIRECT_REF
4757 || (TREE_CODE (t) == RETURN_EXPR && TREE_OPERAND (t, 0)))
4758 search_for_addr_array (TREE_OPERAND (t, 0), location);
4759 else if (TREE_CODE (t) == CALL_EXPR)
4762 call_expr_arg_iterator iter;
4764 FOR_EACH_CALL_EXPR_ARG (arg, iter, t)
4765 search_for_addr_array (arg, location);
4768 if (TREE_CODE (t) == ADDR_EXPR)
4769 *walk_subtree = FALSE;
4774 /* Walk over all statements of all reachable BBs and call check_array_bounds
4778 check_all_array_refs (void)
4781 block_stmt_iterator si;
4785 /* Skip bb's that are clearly unreachable. */
4786 if (single_pred_p (bb))
4788 basic_block pred_bb = EDGE_PRED (bb, 0)->src;
4789 tree ls = NULL_TREE;
4791 if (!bsi_end_p (bsi_last (pred_bb)))
4792 ls = bsi_stmt (bsi_last (pred_bb));
4794 if (ls && TREE_CODE (ls) == COND_EXPR
4795 && ((COND_EXPR_COND (ls) == boolean_false_node
4796 && (EDGE_PRED (bb, 0)->flags & EDGE_TRUE_VALUE))
4797 || (COND_EXPR_COND (ls) == boolean_true_node
4798 && (EDGE_PRED (bb, 0)->flags & EDGE_FALSE_VALUE))))
4801 for (si = bsi_start (bb); !bsi_end_p (si); bsi_next (&si))
4802 walk_tree (bsi_stmt_ptr (si), check_array_bounds,
4803 bsi_stmt (si), NULL);
4807 /* Convert range assertion expressions into the implied copies and
4808 copy propagate away the copies. Doing the trivial copy propagation
4809 here avoids the need to run the full copy propagation pass after
4812 FIXME, this will eventually lead to copy propagation removing the
4813 names that had useful range information attached to them. For
4814 instance, if we had the assertion N_i = ASSERT_EXPR <N_j, N_j > 3>,
4815 then N_i will have the range [3, +INF].
4817 However, by converting the assertion into the implied copy
4818 operation N_i = N_j, we will then copy-propagate N_j into the uses
4819 of N_i and lose the range information. We may want to hold on to
4820 ASSERT_EXPRs a little while longer as the ranges could be used in
4821 things like jump threading.
4823 The problem with keeping ASSERT_EXPRs around is that passes after
4824 VRP need to handle them appropriately.
4826 Another approach would be to make the range information a first
4827 class property of the SSA_NAME so that it can be queried from
4828 any pass. This is made somewhat more complex by the need for
4829 multiple ranges to be associated with one SSA_NAME. */
4832 remove_range_assertions (void)
4835 block_stmt_iterator si;
4837 /* Note that the BSI iterator bump happens at the bottom of the
4838 loop and no bump is necessary if we're removing the statement
4839 referenced by the current BSI. */
4841 for (si = bsi_start (bb); !bsi_end_p (si);)
4843 tree stmt = bsi_stmt (si);
4846 if (TREE_CODE (stmt) == GIMPLE_MODIFY_STMT
4847 && TREE_CODE (GIMPLE_STMT_OPERAND (stmt, 1)) == ASSERT_EXPR)
4849 tree rhs = GIMPLE_STMT_OPERAND (stmt, 1), var;
4850 tree cond = fold (ASSERT_EXPR_COND (rhs));
4851 use_operand_p use_p;
4852 imm_use_iterator iter;
4854 gcc_assert (cond != boolean_false_node);
4856 /* Propagate the RHS into every use of the LHS. */
4857 var = ASSERT_EXPR_VAR (rhs);
4858 FOR_EACH_IMM_USE_STMT (use_stmt, iter,
4859 GIMPLE_STMT_OPERAND (stmt, 0))
4860 FOR_EACH_IMM_USE_ON_STMT (use_p, iter)
4862 SET_USE (use_p, var);
4863 gcc_assert (TREE_CODE (var) == SSA_NAME);
4866 /* And finally, remove the copy, it is not needed. */
4867 bsi_remove (&si, true);
4868 release_defs (stmt);
4874 sbitmap_free (blocks_visited);
4878 /* Return true if STMT is interesting for VRP. */
4881 stmt_interesting_for_vrp (tree stmt)
4883 if (TREE_CODE (stmt) == PHI_NODE
4884 && is_gimple_reg (PHI_RESULT (stmt))
4885 && (INTEGRAL_TYPE_P (TREE_TYPE (PHI_RESULT (stmt)))
4886 || POINTER_TYPE_P (TREE_TYPE (PHI_RESULT (stmt)))))
4888 else if (TREE_CODE (stmt) == GIMPLE_MODIFY_STMT)
4890 tree lhs = GIMPLE_STMT_OPERAND (stmt, 0);
4891 tree rhs = GIMPLE_STMT_OPERAND (stmt, 1);
4893 /* In general, assignments with virtual operands are not useful
4894 for deriving ranges, with the obvious exception of calls to
4895 builtin functions. */
4896 if (TREE_CODE (lhs) == SSA_NAME
4897 && (INTEGRAL_TYPE_P (TREE_TYPE (lhs))
4898 || POINTER_TYPE_P (TREE_TYPE (lhs)))
4899 && ((TREE_CODE (rhs) == CALL_EXPR
4900 && TREE_CODE (CALL_EXPR_FN (rhs)) == ADDR_EXPR
4901 && DECL_P (TREE_OPERAND (CALL_EXPR_FN (rhs), 0))
4902 && DECL_IS_BUILTIN (TREE_OPERAND (CALL_EXPR_FN (rhs), 0)))
4903 || ZERO_SSA_OPERANDS (stmt, SSA_OP_ALL_VIRTUALS)))
4906 else if (TREE_CODE (stmt) == COND_EXPR || TREE_CODE (stmt) == SWITCH_EXPR)
4913 /* Initialize local data structures for VRP. */
4916 vrp_initialize (void)
4920 vr_value = XCNEWVEC (value_range_t *, num_ssa_names);
4921 vr_phi_edge_counts = XCNEWVEC (int, num_ssa_names);
4925 block_stmt_iterator si;
4928 for (phi = phi_nodes (bb); phi; phi = PHI_CHAIN (phi))
4930 if (!stmt_interesting_for_vrp (phi))
4932 tree lhs = PHI_RESULT (phi);
4933 set_value_range_to_varying (get_value_range (lhs));
4934 DONT_SIMULATE_AGAIN (phi) = true;
4937 DONT_SIMULATE_AGAIN (phi) = false;
4940 for (si = bsi_start (bb); !bsi_end_p (si); bsi_next (&si))
4942 tree stmt = bsi_stmt (si);
4944 if (!stmt_interesting_for_vrp (stmt))
4948 FOR_EACH_SSA_TREE_OPERAND (def, stmt, i, SSA_OP_DEF)
4949 set_value_range_to_varying (get_value_range (def));
4950 DONT_SIMULATE_AGAIN (stmt) = true;
4954 DONT_SIMULATE_AGAIN (stmt) = false;
4961 /* Visit assignment STMT. If it produces an interesting range, record
4962 the SSA name in *OUTPUT_P. */
4964 static enum ssa_prop_result
4965 vrp_visit_assignment (tree stmt, tree *output_p)
4970 lhs = GIMPLE_STMT_OPERAND (stmt, 0);
4971 rhs = GIMPLE_STMT_OPERAND (stmt, 1);
4973 /* We only keep track of ranges in integral and pointer types. */
4974 if (TREE_CODE (lhs) == SSA_NAME
4975 && ((INTEGRAL_TYPE_P (TREE_TYPE (lhs))
4976 /* It is valid to have NULL MIN/MAX values on a type. See
4977 build_range_type. */
4978 && TYPE_MIN_VALUE (TREE_TYPE (lhs))
4979 && TYPE_MAX_VALUE (TREE_TYPE (lhs)))
4980 || POINTER_TYPE_P (TREE_TYPE (lhs))))
4983 value_range_t new_vr = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
4985 extract_range_from_expr (&new_vr, rhs);
4987 /* If STMT is inside a loop, we may be able to know something
4988 else about the range of LHS by examining scalar evolution
4990 if (current_loops && (l = loop_containing_stmt (stmt)))
4991 adjust_range_with_scev (&new_vr, l, stmt, lhs);
4993 if (update_value_range (lhs, &new_vr))
4997 if (dump_file && (dump_flags & TDF_DETAILS))
4999 fprintf (dump_file, "Found new range for ");
5000 print_generic_expr (dump_file, lhs, 0);
5001 fprintf (dump_file, ": ");
5002 dump_value_range (dump_file, &new_vr);
5003 fprintf (dump_file, "\n\n");
5006 if (new_vr.type == VR_VARYING)
5007 return SSA_PROP_VARYING;
5009 return SSA_PROP_INTERESTING;
5012 return SSA_PROP_NOT_INTERESTING;
5015 /* Every other statement produces no useful ranges. */
5016 FOR_EACH_SSA_TREE_OPERAND (def, stmt, iter, SSA_OP_DEF)
5017 set_value_range_to_varying (get_value_range (def));
5019 return SSA_PROP_VARYING;
5022 /* Helper that gets the value range of the SSA_NAME with version I
5023 or a symbolic range containing the SSA_NAME only if the value range
5024 is varying or undefined. */
5026 static inline value_range_t
5027 get_vr_for_comparison (int i)
5029 value_range_t vr = *(vr_value[i]);
5031 /* If name N_i does not have a valid range, use N_i as its own
5032 range. This allows us to compare against names that may
5033 have N_i in their ranges. */
5034 if (vr.type == VR_VARYING || vr.type == VR_UNDEFINED)
5037 vr.min = ssa_name (i);
5038 vr.max = ssa_name (i);
5044 /* Compare all the value ranges for names equivalent to VAR with VAL
5045 using comparison code COMP. Return the same value returned by
5046 compare_range_with_value, including the setting of
5047 *STRICT_OVERFLOW_P. */
5050 compare_name_with_value (enum tree_code comp, tree var, tree val,
5051 bool *strict_overflow_p)
5057 int used_strict_overflow;
5059 value_range_t equiv_vr;
5061 /* Get the set of equivalences for VAR. */
5062 e = get_value_range (var)->equiv;
5064 /* Start at -1. Set it to 0 if we do a comparison without relying
5065 on overflow, or 1 if all comparisons rely on overflow. */
5066 used_strict_overflow = -1;
5068 /* Compare vars' value range with val. */
5069 equiv_vr = get_vr_for_comparison (SSA_NAME_VERSION (var));
5071 retval = compare_range_with_value (comp, &equiv_vr, val, &sop);
5073 used_strict_overflow = sop ? 1 : 0;
5075 /* If the equiv set is empty we have done all work we need to do. */
5079 && used_strict_overflow > 0)
5080 *strict_overflow_p = true;
5084 EXECUTE_IF_SET_IN_BITMAP (e, 0, i, bi)
5086 equiv_vr = get_vr_for_comparison (i);
5088 t = compare_range_with_value (comp, &equiv_vr, val, &sop);
5091 /* If we get different answers from different members
5092 of the equivalence set this check must be in a dead
5093 code region. Folding it to a trap representation
5094 would be correct here. For now just return don't-know. */
5104 used_strict_overflow = 0;
5105 else if (used_strict_overflow < 0)
5106 used_strict_overflow = 1;
5111 && used_strict_overflow > 0)
5112 *strict_overflow_p = true;
5118 /* Given a comparison code COMP and names N1 and N2, compare all the
5119 ranges equivalent to N1 against all the ranges equivalent to N2
5120 to determine the value of N1 COMP N2. Return the same value
5121 returned by compare_ranges. Set *STRICT_OVERFLOW_P to indicate
5122 whether we relied on an overflow infinity in the comparison. */
5126 compare_names (enum tree_code comp, tree n1, tree n2,
5127 bool *strict_overflow_p)
5131 bitmap_iterator bi1, bi2;
5133 int used_strict_overflow;
5134 static bitmap_obstack *s_obstack = NULL;
5135 static bitmap s_e1 = NULL, s_e2 = NULL;
5137 /* Compare the ranges of every name equivalent to N1 against the
5138 ranges of every name equivalent to N2. */
5139 e1 = get_value_range (n1)->equiv;
5140 e2 = get_value_range (n2)->equiv;
5142 /* Use the fake bitmaps if e1 or e2 are not available. */
5143 if (s_obstack == NULL)
5145 s_obstack = XNEW (bitmap_obstack);
5146 bitmap_obstack_initialize (s_obstack);
5147 s_e1 = BITMAP_ALLOC (s_obstack);
5148 s_e2 = BITMAP_ALLOC (s_obstack);
5155 /* Add N1 and N2 to their own set of equivalences to avoid
5156 duplicating the body of the loop just to check N1 and N2
5158 bitmap_set_bit (e1, SSA_NAME_VERSION (n1));
5159 bitmap_set_bit (e2, SSA_NAME_VERSION (n2));
5161 /* If the equivalence sets have a common intersection, then the two
5162 names can be compared without checking their ranges. */
5163 if (bitmap_intersect_p (e1, e2))
5165 bitmap_clear_bit (e1, SSA_NAME_VERSION (n1));
5166 bitmap_clear_bit (e2, SSA_NAME_VERSION (n2));
5168 return (comp == EQ_EXPR || comp == GE_EXPR || comp == LE_EXPR)
5170 : boolean_false_node;
5173 /* Start at -1. Set it to 0 if we do a comparison without relying
5174 on overflow, or 1 if all comparisons rely on overflow. */
5175 used_strict_overflow = -1;
5177 /* Otherwise, compare all the equivalent ranges. First, add N1 and
5178 N2 to their own set of equivalences to avoid duplicating the body
5179 of the loop just to check N1 and N2 ranges. */
5180 EXECUTE_IF_SET_IN_BITMAP (e1, 0, i1, bi1)
5182 value_range_t vr1 = get_vr_for_comparison (i1);
5184 t = retval = NULL_TREE;
5185 EXECUTE_IF_SET_IN_BITMAP (e2, 0, i2, bi2)
5189 value_range_t vr2 = get_vr_for_comparison (i2);
5191 t = compare_ranges (comp, &vr1, &vr2, &sop);
5194 /* If we get different answers from different members
5195 of the equivalence set this check must be in a dead
5196 code region. Folding it to a trap representation
5197 would be correct here. For now just return don't-know. */
5201 bitmap_clear_bit (e1, SSA_NAME_VERSION (n1));
5202 bitmap_clear_bit (e2, SSA_NAME_VERSION (n2));
5208 used_strict_overflow = 0;
5209 else if (used_strict_overflow < 0)
5210 used_strict_overflow = 1;
5216 bitmap_clear_bit (e1, SSA_NAME_VERSION (n1));
5217 bitmap_clear_bit (e2, SSA_NAME_VERSION (n2));
5218 if (used_strict_overflow > 0)
5219 *strict_overflow_p = true;
5224 /* None of the equivalent ranges are useful in computing this
5226 bitmap_clear_bit (e1, SSA_NAME_VERSION (n1));
5227 bitmap_clear_bit (e2, SSA_NAME_VERSION (n2));
5231 /* Helper function for vrp_evaluate_conditional_warnv. */
5234 vrp_evaluate_conditional_warnv_with_ops (enum tree_code code, tree op0,
5235 tree op1, bool use_equiv_p,
5236 bool *strict_overflow_p)
5238 /* We only deal with integral and pointer types. */
5239 if (!INTEGRAL_TYPE_P (TREE_TYPE (op0))
5240 && !POINTER_TYPE_P (TREE_TYPE (op0)))
5245 if (TREE_CODE (op0) == SSA_NAME && TREE_CODE (op1) == SSA_NAME)
5246 return compare_names (code, op0, op1,
5248 else if (TREE_CODE (op0) == SSA_NAME)
5249 return compare_name_with_value (code, op0, op1,
5251 else if (TREE_CODE (op1) == SSA_NAME)
5252 return (compare_name_with_value
5253 (swap_tree_comparison (code), op1, op0,
5254 strict_overflow_p));
5258 value_range_t *vr0, *vr1;
5260 vr0 = (TREE_CODE (op0) == SSA_NAME) ? get_value_range (op0) : NULL;
5261 vr1 = (TREE_CODE (op1) == SSA_NAME) ? get_value_range (op1) : NULL;
5264 return compare_ranges (code, vr0, vr1,
5266 else if (vr0 && vr1 == NULL)
5267 return compare_range_with_value (code, vr0, op1,
5269 else if (vr0 == NULL && vr1)
5270 return (compare_range_with_value
5271 (swap_tree_comparison (code), vr1, op0,
5272 strict_overflow_p));
5277 /* Given a conditional predicate COND, try to determine if COND yields
5278 true or false based on the value ranges of its operands. Return
5279 BOOLEAN_TRUE_NODE if the conditional always evaluates to true,
5280 BOOLEAN_FALSE_NODE if the conditional always evaluates to false, and,
5281 NULL if the conditional cannot be evaluated at compile time.
5283 If USE_EQUIV_P is true, the ranges of all the names equivalent with
5284 the operands in COND are used when trying to compute its value.
5285 This is only used during final substitution. During propagation,
5286 we only check the range of each variable and not its equivalents.
5288 Set *STRICT_OVERFLOW_P to indicate whether we relied on an overflow
5289 infinity to produce the result. */
5292 vrp_evaluate_conditional_warnv (tree cond, bool use_equiv_p,
5293 bool *strict_overflow_p)
5295 gcc_assert (TREE_CODE (cond) == SSA_NAME
5296 || TREE_CODE_CLASS (TREE_CODE (cond)) == tcc_comparison);
5298 if (TREE_CODE (cond) == SSA_NAME)
5304 retval = compare_name_with_value (NE_EXPR, cond, boolean_false_node,
5308 value_range_t *vr = get_value_range (cond);
5309 retval = compare_range_with_value (NE_EXPR, vr, boolean_false_node,
5313 /* If COND has a known boolean range, return it. */
5317 /* Otherwise, if COND has a symbolic range of exactly one value,
5319 vr = get_value_range (cond);
5320 if (vr->type == VR_RANGE && vr->min == vr->max)
5324 return vrp_evaluate_conditional_warnv_with_ops (TREE_CODE (cond),
5325 TREE_OPERAND (cond, 0),
5326 TREE_OPERAND (cond, 1),
5330 /* Anything else cannot be computed statically. */
5334 /* Given COND within STMT, try to simplify it based on value range
5335 information. Return NULL if the conditional can not be evaluated.
5336 The ranges of all the names equivalent with the operands in COND
5337 will be used when trying to compute the value. If the result is
5338 based on undefined signed overflow, issue a warning if
5342 vrp_evaluate_conditional (tree cond, tree stmt)
5348 ret = vrp_evaluate_conditional_warnv (cond, true, &sop);
5352 enum warn_strict_overflow_code wc;
5353 const char* warnmsg;
5355 if (is_gimple_min_invariant (ret))
5357 wc = WARN_STRICT_OVERFLOW_CONDITIONAL;
5358 warnmsg = G_("assuming signed overflow does not occur when "
5359 "simplifying conditional to constant");
5363 wc = WARN_STRICT_OVERFLOW_COMPARISON;
5364 warnmsg = G_("assuming signed overflow does not occur when "
5365 "simplifying conditional");
5368 if (issue_strict_overflow_warning (wc))
5372 if (!EXPR_HAS_LOCATION (stmt))
5373 locus = input_location;
5375 locus = EXPR_LOCATION (stmt);
5376 warning (OPT_Wstrict_overflow, "%H%s", &locus, warnmsg);
5380 if (warn_type_limits
5382 && TREE_CODE_CLASS (TREE_CODE (cond)) == tcc_comparison
5383 && TREE_CODE (TREE_OPERAND (cond, 0)) == SSA_NAME)
5385 /* If the comparison is being folded and the operand on the LHS
5386 is being compared against a constant value that is outside of
5387 the natural range of OP0's type, then the predicate will
5388 always fold regardless of the value of OP0. If -Wtype-limits
5389 was specified, emit a warning. */
5390 const char *warnmsg = NULL;
5391 tree op0 = TREE_OPERAND (cond, 0);
5392 tree op1 = TREE_OPERAND (cond, 1);
5393 tree type = TREE_TYPE (op0);
5394 value_range_t *vr0 = get_value_range (op0);
5396 if (vr0->type != VR_VARYING
5397 && INTEGRAL_TYPE_P (type)
5398 && vrp_val_is_min (vr0->min)
5399 && vrp_val_is_max (vr0->max)
5400 && is_gimple_min_invariant (op1))
5402 if (integer_zerop (ret))
5403 warnmsg = G_("comparison always false due to limited range of "
5406 warnmsg = G_("comparison always true due to limited range of "
5414 if (!EXPR_HAS_LOCATION (stmt))
5415 locus = input_location;
5417 locus = EXPR_LOCATION (stmt);
5419 warning (OPT_Wtype_limits, "%H%s", &locus, warnmsg);
5427 /* Visit conditional statement STMT. If we can determine which edge
5428 will be taken out of STMT's basic block, record it in
5429 *TAKEN_EDGE_P and return SSA_PROP_INTERESTING. Otherwise, return
5430 SSA_PROP_VARYING. */
5432 static enum ssa_prop_result
5433 vrp_visit_cond_stmt (tree stmt, edge *taken_edge_p)
5438 *taken_edge_p = NULL;
5439 cond = COND_EXPR_COND (stmt);
5441 if (dump_file && (dump_flags & TDF_DETAILS))
5446 fprintf (dump_file, "\nVisiting conditional with predicate: ");
5447 print_generic_expr (dump_file, cond, 0);
5448 fprintf (dump_file, "\nWith known ranges\n");
5450 FOR_EACH_SSA_TREE_OPERAND (use, stmt, i, SSA_OP_USE)
5452 fprintf (dump_file, "\t");
5453 print_generic_expr (dump_file, use, 0);
5454 fprintf (dump_file, ": ");
5455 dump_value_range (dump_file, vr_value[SSA_NAME_VERSION (use)]);
5458 fprintf (dump_file, "\n");
5461 /* Compute the value of the predicate COND by checking the known
5462 ranges of each of its operands.
5464 Note that we cannot evaluate all the equivalent ranges here
5465 because those ranges may not yet be final and with the current
5466 propagation strategy, we cannot determine when the value ranges
5467 of the names in the equivalence set have changed.
5469 For instance, given the following code fragment
5473 i_14 = ASSERT_EXPR <i_5, i_5 != 0>
5477 Assume that on the first visit to i_14, i_5 has the temporary
5478 range [8, 8] because the second argument to the PHI function is
5479 not yet executable. We derive the range ~[0, 0] for i_14 and the
5480 equivalence set { i_5 }. So, when we visit 'if (i_14 == 1)' for
5481 the first time, since i_14 is equivalent to the range [8, 8], we
5482 determine that the predicate is always false.
5484 On the next round of propagation, i_13 is determined to be
5485 VARYING, which causes i_5 to drop down to VARYING. So, another
5486 visit to i_14 is scheduled. In this second visit, we compute the
5487 exact same range and equivalence set for i_14, namely ~[0, 0] and
5488 { i_5 }. But we did not have the previous range for i_5
5489 registered, so vrp_visit_assignment thinks that the range for
5490 i_14 has not changed. Therefore, the predicate 'if (i_14 == 1)'
5491 is not visited again, which stops propagation from visiting
5492 statements in the THEN clause of that if().
5494 To properly fix this we would need to keep the previous range
5495 value for the names in the equivalence set. This way we would've
5496 discovered that from one visit to the other i_5 changed from
5497 range [8, 8] to VR_VARYING.
5499 However, fixing this apparent limitation may not be worth the
5500 additional checking. Testing on several code bases (GCC, DLV,
5501 MICO, TRAMP3D and SPEC2000) showed that doing this results in
5502 4 more predicates folded in SPEC. */
5504 val = vrp_evaluate_conditional_warnv (cond, false, &sop);
5508 *taken_edge_p = find_taken_edge (bb_for_stmt (stmt), val);
5511 if (dump_file && (dump_flags & TDF_DETAILS))
5513 "\nIgnoring predicate evaluation because "
5514 "it assumes that signed overflow is undefined");
5519 if (dump_file && (dump_flags & TDF_DETAILS))
5521 fprintf (dump_file, "\nPredicate evaluates to: ");
5522 if (val == NULL_TREE)
5523 fprintf (dump_file, "DON'T KNOW\n");
5525 print_generic_stmt (dump_file, val, 0);
5528 return (*taken_edge_p) ? SSA_PROP_INTERESTING : SSA_PROP_VARYING;
5532 /* Searches the case label vector VEC for the index *IDX the CASE_LABEL
5533 includes the value VAL. The search starts at index START_IDX and
5534 true is returned if *IDX corresponds to such an index. False is
5535 returned in case VAL hits the default case label and *IDX in this
5536 case is the next higher or the next lower case label index. */
5539 find_case_label_index (tree vec, size_t start_idx, tree val, size_t *idx)
5541 size_t n = TREE_VEC_LENGTH (vec);
5542 size_t low, high, i = start_idx;
5544 /* Find case label for minimum of the value range or the next one. */
5545 for (low = start_idx - 1, high = n - 1; high - low > 1; )
5549 i = (high + low) / 2;
5550 t = TREE_VEC_ELT (vec, i);
5552 /* Cache the result of comparing CASE_LOW and val. */
5553 cmp = tree_int_cst_compare (CASE_LOW (t), val);
5560 if (CASE_HIGH (t) == NULL)
5562 /* A singe-valued case label. */
5571 /* A case range. We can only handle integer ranges. */
5572 if (cmp <= 0 && tree_int_cst_compare (CASE_HIGH (t), val) >= 0)
5584 /* Visit switch statement STMT. If we can determine which edge
5585 will be taken out of STMT's basic block, record it in
5586 *TAKEN_EDGE_P and return SSA_PROP_INTERESTING. Otherwise, return
5587 SSA_PROP_VARYING. */
5589 static enum ssa_prop_result
5590 vrp_visit_switch_stmt (tree stmt, edge *taken_edge_p)
5594 size_t i = 0, j = 0, n;
5596 bool min_take_default, max_take_default;
5598 *taken_edge_p = NULL;
5599 op = TREE_OPERAND (stmt, 0);
5600 if (TREE_CODE (op) != SSA_NAME)
5601 return SSA_PROP_VARYING;
5603 vr = get_value_range (op);
5604 if (dump_file && (dump_flags & TDF_DETAILS))
5606 fprintf (dump_file, "\nVisiting switch expression with operand ");
5607 print_generic_expr (dump_file, op, 0);
5608 fprintf (dump_file, " with known range ");
5609 dump_value_range (dump_file, vr);
5610 fprintf (dump_file, "\n");
5613 if (vr->type != VR_RANGE
5614 || symbolic_range_p (vr))
5615 return SSA_PROP_VARYING;
5617 /* Find the single edge that is taken from the switch expression. */
5618 vec = SWITCH_LABELS (stmt);
5619 n = TREE_VEC_LENGTH (vec);
5621 /* Find case label for minimum of the value range or the next one. */
5622 min_take_default = !find_case_label_index (vec, 0, vr->min, &i);
5624 /* Find case label for maximum of the value range or the previous one. */
5625 max_take_default = !find_case_label_index (vec, i, vr->max, &j);
5627 /* Check if we reach the default label only. */
5629 val = TREE_VEC_ELT (vec, n - 1);
5630 /* Check if we reach exactly one label and not the default label. */
5632 && !min_take_default
5633 && !max_take_default)
5634 val = TREE_VEC_ELT (vec, i);
5637 /* Check if labels with index i to j are all reaching the same label.
5638 If we don't hit a single case label only, the default case also has
5639 to branch to the same label. */
5640 val = TREE_VEC_ELT (vec, i);
5641 if (CASE_LABEL (TREE_VEC_ELT (vec, n - 1)) != CASE_LABEL (val))
5643 if (dump_file && (dump_flags & TDF_DETAILS))
5644 fprintf (dump_file, " not a single destination for this "
5646 return SSA_PROP_VARYING;
5648 for (++i; i <= j; ++i)
5650 if (CASE_LABEL (TREE_VEC_ELT (vec, i)) != CASE_LABEL (val))
5652 if (dump_file && (dump_flags & TDF_DETAILS))
5653 fprintf (dump_file, " not a single destination for this "
5655 return SSA_PROP_VARYING;
5660 *taken_edge_p = find_edge (bb_for_stmt (stmt),
5661 label_to_block (CASE_LABEL (val)));
5663 if (dump_file && (dump_flags & TDF_DETAILS))
5665 fprintf (dump_file, " will take edge to ");
5666 print_generic_stmt (dump_file, CASE_LABEL (val), 0);
5669 return SSA_PROP_INTERESTING;
5673 /* Evaluate statement STMT. If the statement produces a useful range,
5674 return SSA_PROP_INTERESTING and record the SSA name with the
5675 interesting range into *OUTPUT_P.
5677 If STMT is a conditional branch and we can determine its truth
5678 value, the taken edge is recorded in *TAKEN_EDGE_P.
5680 If STMT produces a varying value, return SSA_PROP_VARYING. */
5682 static enum ssa_prop_result
5683 vrp_visit_stmt (tree stmt, edge *taken_edge_p, tree *output_p)
5689 if (dump_file && (dump_flags & TDF_DETAILS))
5691 fprintf (dump_file, "\nVisiting statement:\n");
5692 print_generic_stmt (dump_file, stmt, dump_flags);
5693 fprintf (dump_file, "\n");
5696 ann = stmt_ann (stmt);
5697 if (TREE_CODE (stmt) == GIMPLE_MODIFY_STMT)
5699 tree rhs = GIMPLE_STMT_OPERAND (stmt, 1);
5701 /* In general, assignments with virtual operands are not useful
5702 for deriving ranges, with the obvious exception of calls to
5703 builtin functions. */
5704 if ((TREE_CODE (rhs) == CALL_EXPR
5705 && TREE_CODE (CALL_EXPR_FN (rhs)) == ADDR_EXPR
5706 && DECL_P (TREE_OPERAND (CALL_EXPR_FN (rhs), 0))
5707 && DECL_IS_BUILTIN (TREE_OPERAND (CALL_EXPR_FN (rhs), 0)))
5708 || ZERO_SSA_OPERANDS (stmt, SSA_OP_ALL_VIRTUALS))
5709 return vrp_visit_assignment (stmt, output_p);
5711 else if (TREE_CODE (stmt) == COND_EXPR)
5712 return vrp_visit_cond_stmt (stmt, taken_edge_p);
5713 else if (TREE_CODE (stmt) == SWITCH_EXPR)
5714 return vrp_visit_switch_stmt (stmt, taken_edge_p);
5716 /* All other statements produce nothing of interest for VRP, so mark
5717 their outputs varying and prevent further simulation. */
5718 FOR_EACH_SSA_TREE_OPERAND (def, stmt, iter, SSA_OP_DEF)
5719 set_value_range_to_varying (get_value_range (def));
5721 return SSA_PROP_VARYING;
5725 /* Meet operation for value ranges. Given two value ranges VR0 and
5726 VR1, store in VR0 a range that contains both VR0 and VR1. This
5727 may not be the smallest possible such range. */
5730 vrp_meet (value_range_t *vr0, value_range_t *vr1)
5732 if (vr0->type == VR_UNDEFINED)
5734 copy_value_range (vr0, vr1);
5738 if (vr1->type == VR_UNDEFINED)
5740 /* Nothing to do. VR0 already has the resulting range. */
5744 if (vr0->type == VR_VARYING)
5746 /* Nothing to do. VR0 already has the resulting range. */
5750 if (vr1->type == VR_VARYING)
5752 set_value_range_to_varying (vr0);
5756 if (vr0->type == VR_RANGE && vr1->type == VR_RANGE)
5761 /* Compute the convex hull of the ranges. The lower limit of
5762 the new range is the minimum of the two ranges. If they
5763 cannot be compared, then give up. */
5764 cmp = compare_values (vr0->min, vr1->min);
5765 if (cmp == 0 || cmp == 1)
5772 /* Similarly, the upper limit of the new range is the maximum
5773 of the two ranges. If they cannot be compared, then
5775 cmp = compare_values (vr0->max, vr1->max);
5776 if (cmp == 0 || cmp == -1)
5783 /* Check for useless ranges. */
5784 if (INTEGRAL_TYPE_P (TREE_TYPE (min))
5785 && ((vrp_val_is_min (min) || is_overflow_infinity (min))
5786 && (vrp_val_is_max (max) || is_overflow_infinity (max))))
5789 /* The resulting set of equivalences is the intersection of
5791 if (vr0->equiv && vr1->equiv && vr0->equiv != vr1->equiv)
5792 bitmap_and_into (vr0->equiv, vr1->equiv);
5793 else if (vr0->equiv && !vr1->equiv)
5794 bitmap_clear (vr0->equiv);
5796 set_value_range (vr0, vr0->type, min, max, vr0->equiv);
5798 else if (vr0->type == VR_ANTI_RANGE && vr1->type == VR_ANTI_RANGE)
5800 /* Two anti-ranges meet only if their complements intersect.
5801 Only handle the case of identical ranges. */
5802 if (compare_values (vr0->min, vr1->min) == 0
5803 && compare_values (vr0->max, vr1->max) == 0
5804 && compare_values (vr0->min, vr0->max) == 0)
5806 /* The resulting set of equivalences is the intersection of
5808 if (vr0->equiv && vr1->equiv && vr0->equiv != vr1->equiv)
5809 bitmap_and_into (vr0->equiv, vr1->equiv);
5810 else if (vr0->equiv && !vr1->equiv)
5811 bitmap_clear (vr0->equiv);
5816 else if (vr0->type == VR_ANTI_RANGE || vr1->type == VR_ANTI_RANGE)
5818 /* For a numeric range [VAL1, VAL2] and an anti-range ~[VAL3, VAL4],
5819 only handle the case where the ranges have an empty intersection.
5820 The result of the meet operation is the anti-range. */
5821 if (!symbolic_range_p (vr0)
5822 && !symbolic_range_p (vr1)
5823 && !value_ranges_intersect_p (vr0, vr1))
5825 /* Copy most of VR1 into VR0. Don't copy VR1's equivalence
5826 set. We need to compute the intersection of the two
5827 equivalence sets. */
5828 if (vr1->type == VR_ANTI_RANGE)
5829 set_value_range (vr0, vr1->type, vr1->min, vr1->max, vr0->equiv);
5831 /* The resulting set of equivalences is the intersection of
5833 if (vr0->equiv && vr1->equiv && vr0->equiv != vr1->equiv)
5834 bitmap_and_into (vr0->equiv, vr1->equiv);
5835 else if (vr0->equiv && !vr1->equiv)
5836 bitmap_clear (vr0->equiv);
5847 /* Failed to find an efficient meet. Before giving up and setting
5848 the result to VARYING, see if we can at least derive a useful
5849 anti-range. FIXME, all this nonsense about distinguishing
5850 anti-ranges from ranges is necessary because of the odd
5851 semantics of range_includes_zero_p and friends. */
5852 if (!symbolic_range_p (vr0)
5853 && ((vr0->type == VR_RANGE && !range_includes_zero_p (vr0))
5854 || (vr0->type == VR_ANTI_RANGE && range_includes_zero_p (vr0)))
5855 && !symbolic_range_p (vr1)
5856 && ((vr1->type == VR_RANGE && !range_includes_zero_p (vr1))
5857 || (vr1->type == VR_ANTI_RANGE && range_includes_zero_p (vr1))))
5859 set_value_range_to_nonnull (vr0, TREE_TYPE (vr0->min));
5861 /* Since this meet operation did not result from the meeting of
5862 two equivalent names, VR0 cannot have any equivalences. */
5864 bitmap_clear (vr0->equiv);
5867 set_value_range_to_varying (vr0);
5871 /* Visit all arguments for PHI node PHI that flow through executable
5872 edges. If a valid value range can be derived from all the incoming
5873 value ranges, set a new range for the LHS of PHI. */
5875 static enum ssa_prop_result
5876 vrp_visit_phi_node (tree phi)
5879 tree lhs = PHI_RESULT (phi);
5880 value_range_t *lhs_vr = get_value_range (lhs);
5881 value_range_t vr_result = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
5882 int edges, old_edges;
5884 copy_value_range (&vr_result, lhs_vr);
5886 if (dump_file && (dump_flags & TDF_DETAILS))
5888 fprintf (dump_file, "\nVisiting PHI node: ");
5889 print_generic_expr (dump_file, phi, dump_flags);
5893 for (i = 0; i < PHI_NUM_ARGS (phi); i++)
5895 edge e = PHI_ARG_EDGE (phi, i);
5897 if (dump_file && (dump_flags & TDF_DETAILS))
5900 "\n Argument #%d (%d -> %d %sexecutable)\n",
5901 i, e->src->index, e->dest->index,
5902 (e->flags & EDGE_EXECUTABLE) ? "" : "not ");
5905 if (e->flags & EDGE_EXECUTABLE)
5907 tree arg = PHI_ARG_DEF (phi, i);
5908 value_range_t vr_arg;
5912 if (TREE_CODE (arg) == SSA_NAME)
5914 vr_arg = *(get_value_range (arg));
5918 if (is_overflow_infinity (arg))
5920 arg = copy_node (arg);
5921 TREE_OVERFLOW (arg) = 0;
5924 vr_arg.type = VR_RANGE;
5927 vr_arg.equiv = NULL;
5930 if (dump_file && (dump_flags & TDF_DETAILS))
5932 fprintf (dump_file, "\t");
5933 print_generic_expr (dump_file, arg, dump_flags);
5934 fprintf (dump_file, "\n\tValue: ");
5935 dump_value_range (dump_file, &vr_arg);
5936 fprintf (dump_file, "\n");
5939 vrp_meet (&vr_result, &vr_arg);
5941 if (vr_result.type == VR_VARYING)
5946 if (vr_result.type == VR_VARYING)
5949 old_edges = vr_phi_edge_counts[SSA_NAME_VERSION (lhs)];
5950 vr_phi_edge_counts[SSA_NAME_VERSION (lhs)] = edges;
5952 /* To prevent infinite iterations in the algorithm, derive ranges
5953 when the new value is slightly bigger or smaller than the
5954 previous one. We don't do this if we have seen a new executable
5955 edge; this helps us avoid an overflow infinity for conditionals
5956 which are not in a loop. */
5957 if (lhs_vr->type == VR_RANGE && vr_result.type == VR_RANGE
5958 && edges <= old_edges)
5960 if (!POINTER_TYPE_P (TREE_TYPE (lhs)))
5962 int cmp_min = compare_values (lhs_vr->min, vr_result.min);
5963 int cmp_max = compare_values (lhs_vr->max, vr_result.max);
5965 /* If the new minimum is smaller or larger than the previous
5966 one, go all the way to -INF. In the first case, to avoid
5967 iterating millions of times to reach -INF, and in the
5968 other case to avoid infinite bouncing between different
5970 if (cmp_min > 0 || cmp_min < 0)
5972 /* If we will end up with a (-INF, +INF) range, set it
5974 if (vrp_val_is_max (vr_result.max))
5977 if (!needs_overflow_infinity (TREE_TYPE (vr_result.min))
5978 || !vrp_var_may_overflow (lhs, phi))
5979 vr_result.min = TYPE_MIN_VALUE (TREE_TYPE (vr_result.min));
5980 else if (supports_overflow_infinity (TREE_TYPE (vr_result.min)))
5982 negative_overflow_infinity (TREE_TYPE (vr_result.min));
5987 /* Similarly, if the new maximum is smaller or larger than
5988 the previous one, go all the way to +INF. */
5989 if (cmp_max < 0 || cmp_max > 0)
5991 /* If we will end up with a (-INF, +INF) range, set it
5993 if (vrp_val_is_min (vr_result.min))
5996 if (!needs_overflow_infinity (TREE_TYPE (vr_result.max))
5997 || !vrp_var_may_overflow (lhs, phi))
5998 vr_result.max = TYPE_MAX_VALUE (TREE_TYPE (vr_result.max));
5999 else if (supports_overflow_infinity (TREE_TYPE (vr_result.max)))
6001 positive_overflow_infinity (TREE_TYPE (vr_result.max));
6008 /* If the new range is different than the previous value, keep
6010 if (update_value_range (lhs, &vr_result))
6011 return SSA_PROP_INTERESTING;
6013 /* Nothing changed, don't add outgoing edges. */
6014 return SSA_PROP_NOT_INTERESTING;
6016 /* No match found. Set the LHS to VARYING. */
6018 set_value_range_to_varying (lhs_vr);
6019 return SSA_PROP_VARYING;
6022 /* Simplify a division or modulo operator to a right shift or
6023 bitwise and if the first operand is unsigned or is greater
6024 than zero and the second operand is an exact power of two. */
6027 simplify_div_or_mod_using_ranges (tree stmt, tree rhs, enum tree_code rhs_code)
6030 tree op = TREE_OPERAND (rhs, 0);
6031 value_range_t *vr = get_value_range (TREE_OPERAND (rhs, 0));
6033 if (TYPE_UNSIGNED (TREE_TYPE (op)))
6035 val = integer_one_node;
6041 val = compare_range_with_value (GE_EXPR, vr, integer_zero_node, &sop);
6045 && integer_onep (val)
6046 && issue_strict_overflow_warning (WARN_STRICT_OVERFLOW_MISC))
6050 if (!EXPR_HAS_LOCATION (stmt))
6051 locus = input_location;
6053 locus = EXPR_LOCATION (stmt);
6054 warning (OPT_Wstrict_overflow,
6055 ("%Hassuming signed overflow does not occur when "
6056 "simplifying / or %% to >> or &"),
6061 if (val && integer_onep (val))
6064 tree op0 = TREE_OPERAND (rhs, 0);
6065 tree op1 = TREE_OPERAND (rhs, 1);
6067 if (rhs_code == TRUNC_DIV_EXPR)
6069 t = build_int_cst (NULL_TREE, tree_log2 (op1));
6070 t = build2 (RSHIFT_EXPR, TREE_TYPE (op0), op0, t);
6074 t = build_int_cst (TREE_TYPE (op1), 1);
6075 t = int_const_binop (MINUS_EXPR, op1, t, 0);
6076 t = fold_convert (TREE_TYPE (op0), t);
6077 t = build2 (BIT_AND_EXPR, TREE_TYPE (op0), op0, t);
6080 GIMPLE_STMT_OPERAND (stmt, 1) = t;
6085 /* If the operand to an ABS_EXPR is >= 0, then eliminate the
6086 ABS_EXPR. If the operand is <= 0, then simplify the
6087 ABS_EXPR into a NEGATE_EXPR. */
6090 simplify_abs_using_ranges (tree stmt, tree rhs)
6093 tree op = TREE_OPERAND (rhs, 0);
6094 tree type = TREE_TYPE (op);
6095 value_range_t *vr = get_value_range (TREE_OPERAND (rhs, 0));
6097 if (TYPE_UNSIGNED (type))
6099 val = integer_zero_node;
6105 val = compare_range_with_value (LE_EXPR, vr, integer_zero_node, &sop);
6109 val = compare_range_with_value (GE_EXPR, vr, integer_zero_node,
6114 if (integer_zerop (val))
6115 val = integer_one_node;
6116 else if (integer_onep (val))
6117 val = integer_zero_node;
6122 && (integer_onep (val) || integer_zerop (val)))
6126 if (sop && issue_strict_overflow_warning (WARN_STRICT_OVERFLOW_MISC))
6130 if (!EXPR_HAS_LOCATION (stmt))
6131 locus = input_location;
6133 locus = EXPR_LOCATION (stmt);
6134 warning (OPT_Wstrict_overflow,
6135 ("%Hassuming signed overflow does not occur when "
6136 "simplifying abs (X) to X or -X"),
6140 if (integer_onep (val))
6141 t = build1 (NEGATE_EXPR, TREE_TYPE (op), op);
6145 GIMPLE_STMT_OPERAND (stmt, 1) = t;
6151 /* We are comparing trees OP0 and OP1 using COND_CODE. OP0 has
6152 a known value range VR.
6154 If there is one and only one value which will satisfy the
6155 conditional, then return that value. Else return NULL. */
6158 test_for_singularity (enum tree_code cond_code, tree op0,
6159 tree op1, value_range_t *vr)
6164 /* Extract minimum/maximum values which satisfy the
6165 the conditional as it was written. */
6166 if (cond_code == LE_EXPR || cond_code == LT_EXPR)
6168 /* This should not be negative infinity; there is no overflow
6170 min = TYPE_MIN_VALUE (TREE_TYPE (op0));
6173 if (cond_code == LT_EXPR && !is_overflow_infinity (max))
6175 tree one = build_int_cst (TREE_TYPE (op0), 1);
6176 max = fold_build2 (MINUS_EXPR, TREE_TYPE (op0), max, one);
6178 TREE_NO_WARNING (max) = 1;
6181 else if (cond_code == GE_EXPR || cond_code == GT_EXPR)
6183 /* This should not be positive infinity; there is no overflow
6185 max = TYPE_MAX_VALUE (TREE_TYPE (op0));
6188 if (cond_code == GT_EXPR && !is_overflow_infinity (min))
6190 tree one = build_int_cst (TREE_TYPE (op0), 1);
6191 min = fold_build2 (PLUS_EXPR, TREE_TYPE (op0), min, one);
6193 TREE_NO_WARNING (min) = 1;
6197 /* Now refine the minimum and maximum values using any
6198 value range information we have for op0. */
6201 if (compare_values (vr->min, min) == -1)
6205 if (compare_values (vr->max, max) == 1)
6210 /* If the new min/max values have converged to a single value,
6211 then there is only one value which can satisfy the condition,
6212 return that value. */
6213 if (operand_equal_p (min, max, 0) && is_gimple_min_invariant (min))
6219 /* Simplify a conditional using a relational operator to an equality
6220 test if the range information indicates only one value can satisfy
6221 the original conditional. */
6224 simplify_cond_using_ranges (tree stmt)
6226 tree cond = COND_EXPR_COND (stmt);
6227 tree op0 = TREE_OPERAND (cond, 0);
6228 tree op1 = TREE_OPERAND (cond, 1);
6229 enum tree_code cond_code = TREE_CODE (cond);
6231 if (cond_code != NE_EXPR
6232 && cond_code != EQ_EXPR
6233 && TREE_CODE (op0) == SSA_NAME
6234 && INTEGRAL_TYPE_P (TREE_TYPE (op0))
6235 && is_gimple_min_invariant (op1))
6237 value_range_t *vr = get_value_range (op0);
6239 /* If we have range information for OP0, then we might be
6240 able to simplify this conditional. */
6241 if (vr->type == VR_RANGE)
6243 tree new = test_for_singularity (cond_code, op0, op1, vr);
6249 fprintf (dump_file, "Simplified relational ");
6250 print_generic_expr (dump_file, cond, 0);
6251 fprintf (dump_file, " into ");
6254 COND_EXPR_COND (stmt)
6255 = build2 (EQ_EXPR, boolean_type_node, op0, new);
6260 print_generic_expr (dump_file, COND_EXPR_COND (stmt), 0);
6261 fprintf (dump_file, "\n");
6267 /* Try again after inverting the condition. We only deal
6268 with integral types here, so no need to worry about
6269 issues with inverting FP comparisons. */
6270 cond_code = invert_tree_comparison (cond_code, false);
6271 new = test_for_singularity (cond_code, op0, op1, vr);
6277 fprintf (dump_file, "Simplified relational ");
6278 print_generic_expr (dump_file, cond, 0);
6279 fprintf (dump_file, " into ");
6282 COND_EXPR_COND (stmt)
6283 = build2 (NE_EXPR, boolean_type_node, op0, new);
6288 print_generic_expr (dump_file, COND_EXPR_COND (stmt), 0);
6289 fprintf (dump_file, "\n");
6298 /* Simplify a switch statement using the value range of the switch
6302 simplify_switch_using_ranges (tree stmt)
6304 tree op = TREE_OPERAND (stmt, 0);
6309 size_t i = 0, j = 0, n, n2;
6313 if (TREE_CODE (op) != SSA_NAME)
6316 vr = get_value_range (op);
6318 /* We can only handle integer ranges. */
6319 if (vr->type != VR_RANGE
6320 || symbolic_range_p (vr))
6323 /* Find case label for min/max of the value range. */
6324 vec = SWITCH_LABELS (stmt);
6325 n = TREE_VEC_LENGTH (vec);
6326 take_default = !find_case_label_index (vec, 0, vr->min, &i);
6327 take_default |= !find_case_label_index (vec, i, vr->max, &j);
6329 /* If the case label range is continuous, we do not need to
6330 preserve the default case label. Verify that. */
6331 if (!take_default && j > i)
6336 high = CASE_LOW (TREE_VEC_ELT (vec, i));
6337 if (CASE_HIGH (TREE_VEC_ELT (vec, i)))
6338 high = CASE_HIGH (TREE_VEC_ELT (vec, i));
6339 for (k = i + 1; k <= j; ++k)
6341 low = CASE_LOW (TREE_VEC_ELT (vec, k));
6342 if (!integer_onep (int_const_binop (MINUS_EXPR, low, high, 0)))
6344 take_default = true;
6348 if (CASE_HIGH (TREE_VEC_ELT (vec, k)))
6349 high = CASE_HIGH (TREE_VEC_ELT (vec, k));
6353 /* Bail out if this is just all edges taken. */
6359 /* Build a new vector of taken case labels. */
6360 vec2 = make_tree_vec (j - i + 1 + (int)take_default);
6361 for (n2 = 0; i <= j; ++i, ++n2)
6362 TREE_VEC_ELT (vec2, n2) = TREE_VEC_ELT (vec, i);
6364 /* Add the default edge, if necessary. */
6366 TREE_VEC_ELT (vec2, n2++) = TREE_VEC_ELT (vec, n - 1);
6368 /* Mark needed edges. */
6369 for (i = 0; i < n2; ++i)
6371 e = find_edge (bb_for_stmt (stmt),
6372 label_to_block (CASE_LABEL (TREE_VEC_ELT (vec2, i))));
6373 e->aux = (void *)-1;
6376 /* Queue not needed edges for later removal. */
6377 FOR_EACH_EDGE (e, ei, bb_for_stmt (stmt)->succs)
6379 if (e->aux == (void *)-1)
6385 if (dump_file && (dump_flags & TDF_DETAILS))
6387 fprintf (dump_file, "removing unreachable case label\n");
6389 VEC_safe_push (edge, heap, to_remove_edges, e);
6392 /* And queue an update for the stmt. */
6395 VEC_safe_push (switch_update, heap, to_update_switch_stmts, &su);
6398 /* Simplify STMT using ranges if possible. */
6401 simplify_stmt_using_ranges (tree stmt)
6403 if (TREE_CODE (stmt) == GIMPLE_MODIFY_STMT)
6405 tree rhs = GIMPLE_STMT_OPERAND (stmt, 1);
6406 enum tree_code rhs_code = TREE_CODE (rhs);
6408 /* Transform TRUNC_DIV_EXPR and TRUNC_MOD_EXPR into RSHIFT_EXPR
6409 and BIT_AND_EXPR respectively if the first operand is greater
6410 than zero and the second operand is an exact power of two. */
6411 if ((rhs_code == TRUNC_DIV_EXPR || rhs_code == TRUNC_MOD_EXPR)
6412 && INTEGRAL_TYPE_P (TREE_TYPE (TREE_OPERAND (rhs, 0)))
6413 && integer_pow2p (TREE_OPERAND (rhs, 1)))
6414 simplify_div_or_mod_using_ranges (stmt, rhs, rhs_code);
6416 /* Transform ABS (X) into X or -X as appropriate. */
6417 if (rhs_code == ABS_EXPR
6418 && TREE_CODE (TREE_OPERAND (rhs, 0)) == SSA_NAME
6419 && INTEGRAL_TYPE_P (TREE_TYPE (TREE_OPERAND (rhs, 0))))
6420 simplify_abs_using_ranges (stmt, rhs);
6422 else if (TREE_CODE (stmt) == COND_EXPR
6423 && COMPARISON_CLASS_P (COND_EXPR_COND (stmt)))
6424 simplify_cond_using_ranges (stmt);
6425 else if (TREE_CODE (stmt) == SWITCH_EXPR)
6426 simplify_switch_using_ranges (stmt);
6429 /* Stack of dest,src equivalency pairs that need to be restored after
6430 each attempt to thread a block's incoming edge to an outgoing edge.
6432 A NULL entry is used to mark the end of pairs which need to be
6434 static VEC(tree,heap) *stack;
6436 /* A trivial wrapper so that we can present the generic jump threading
6437 code with a simple API for simplifying statements. STMT is the
6438 statement we want to simplify, WITHIN_STMT provides the location
6439 for any overflow warnings. */
6442 simplify_stmt_for_jump_threading (tree stmt, tree within_stmt)
6444 /* We only use VRP information to simplify conditionals. This is
6445 overly conservative, but it's unclear if doing more would be
6446 worth the compile time cost. */
6447 if (TREE_CODE (stmt) != COND_EXPR)
6450 return vrp_evaluate_conditional (COND_EXPR_COND (stmt), within_stmt);
6453 /* Blocks which have more than one predecessor and more than
6454 one successor present jump threading opportunities. ie,
6455 when the block is reached from a specific predecessor, we
6456 may be able to determine which of the outgoing edges will
6457 be traversed. When this optimization applies, we are able
6458 to avoid conditionals at runtime and we may expose secondary
6459 optimization opportunities.
6461 This routine is effectively a driver for the generic jump
6462 threading code. It basically just presents the generic code
6463 with edges that may be suitable for jump threading.
6465 Unlike DOM, we do not iterate VRP if jump threading was successful.
6466 While iterating may expose new opportunities for VRP, it is expected
6467 those opportunities would be very limited and the compile time cost
6468 to expose those opportunities would be significant.
6470 As jump threading opportunities are discovered, they are registered
6471 for later realization. */
6474 identify_jump_threads (void)
6481 /* Ugh. When substituting values earlier in this pass we can
6482 wipe the dominance information. So rebuild the dominator
6483 information as we need it within the jump threading code. */
6484 calculate_dominance_info (CDI_DOMINATORS);
6486 /* We do not allow VRP information to be used for jump threading
6487 across a back edge in the CFG. Otherwise it becomes too
6488 difficult to avoid eliminating loop exit tests. Of course
6489 EDGE_DFS_BACK is not accurate at this time so we have to
6491 mark_dfs_back_edges ();
6493 /* Do not thread across edges we are about to remove. Just marking
6494 them as EDGE_DFS_BACK will do. */
6495 for (i = 0; VEC_iterate (edge, to_remove_edges, i, e); ++i)
6496 e->flags |= EDGE_DFS_BACK;
6498 /* Allocate our unwinder stack to unwind any temporary equivalences
6499 that might be recorded. */
6500 stack = VEC_alloc (tree, heap, 20);
6502 /* To avoid lots of silly node creation, we create a single
6503 conditional and just modify it in-place when attempting to
6505 dummy = build2 (EQ_EXPR, boolean_type_node, NULL, NULL);
6506 dummy = build3 (COND_EXPR, void_type_node, dummy, NULL, NULL);
6508 /* Walk through all the blocks finding those which present a
6509 potential jump threading opportunity. We could set this up
6510 as a dominator walker and record data during the walk, but
6511 I doubt it's worth the effort for the classes of jump
6512 threading opportunities we are trying to identify at this
6513 point in compilation. */
6518 /* If the generic jump threading code does not find this block
6519 interesting, then there is nothing to do. */
6520 if (! potentially_threadable_block (bb))
6523 /* We only care about blocks ending in a COND_EXPR. While there
6524 may be some value in handling SWITCH_EXPR here, I doubt it's
6525 terribly important. */
6526 last = bsi_stmt (bsi_last (bb));
6527 if (TREE_CODE (last) != COND_EXPR)
6530 /* We're basically looking for any kind of conditional with
6531 integral type arguments. */
6532 cond = COND_EXPR_COND (last);
6533 if ((TREE_CODE (cond) == SSA_NAME
6534 && INTEGRAL_TYPE_P (TREE_TYPE (cond)))
6535 || (COMPARISON_CLASS_P (cond)
6536 && TREE_CODE (TREE_OPERAND (cond, 0)) == SSA_NAME
6537 && INTEGRAL_TYPE_P (TREE_TYPE (TREE_OPERAND (cond, 0)))
6538 && (TREE_CODE (TREE_OPERAND (cond, 1)) == SSA_NAME
6539 || is_gimple_min_invariant (TREE_OPERAND (cond, 1)))
6540 && INTEGRAL_TYPE_P (TREE_TYPE (TREE_OPERAND (cond, 1)))))
6544 /* We've got a block with multiple predecessors and multiple
6545 successors which also ends in a suitable conditional. For
6546 each predecessor, see if we can thread it to a specific
6548 FOR_EACH_EDGE (e, ei, bb->preds)
6550 /* Do not thread across back edges or abnormal edges
6552 if (e->flags & (EDGE_DFS_BACK | EDGE_COMPLEX))
6555 thread_across_edge (dummy, e, true,
6557 simplify_stmt_for_jump_threading);
6562 /* We do not actually update the CFG or SSA graphs at this point as
6563 ASSERT_EXPRs are still in the IL and cfg cleanup code does not yet
6564 handle ASSERT_EXPRs gracefully. */
6567 /* We identified all the jump threading opportunities earlier, but could
6568 not transform the CFG at that time. This routine transforms the
6569 CFG and arranges for the dominator tree to be rebuilt if necessary.
6571 Note the SSA graph update will occur during the normal TODO
6572 processing by the pass manager. */
6574 finalize_jump_threads (void)
6576 thread_through_all_blocks (false);
6577 VEC_free (tree, heap, stack);
6581 /* Traverse all the blocks folding conditionals with known ranges. */
6587 prop_value_t *single_val_range;
6588 bool do_value_subst_p;
6592 fprintf (dump_file, "\nValue ranges after VRP:\n\n");
6593 dump_all_value_ranges (dump_file);
6594 fprintf (dump_file, "\n");
6597 /* We may have ended with ranges that have exactly one value. Those
6598 values can be substituted as any other copy/const propagated
6599 value using substitute_and_fold. */
6600 single_val_range = XCNEWVEC (prop_value_t, num_ssa_names);
6602 do_value_subst_p = false;
6603 for (i = 0; i < num_ssa_names; i++)
6605 && vr_value[i]->type == VR_RANGE
6606 && vr_value[i]->min == vr_value[i]->max)
6608 single_val_range[i].value = vr_value[i]->min;
6609 do_value_subst_p = true;
6612 if (!do_value_subst_p)
6614 /* We found no single-valued ranges, don't waste time trying to
6615 do single value substitution in substitute_and_fold. */
6616 free (single_val_range);
6617 single_val_range = NULL;
6620 substitute_and_fold (single_val_range, true);
6622 if (warn_array_bounds)
6623 check_all_array_refs ();
6625 /* We must identify jump threading opportunities before we release
6626 the datastructures built by VRP. */
6627 identify_jump_threads ();
6629 /* Free allocated memory. */
6630 for (i = 0; i < num_ssa_names; i++)
6633 BITMAP_FREE (vr_value[i]->equiv);
6637 free (single_val_range);
6639 free (vr_phi_edge_counts);
6641 /* So that we can distinguish between VRP data being available
6642 and not available. */
6644 vr_phi_edge_counts = NULL;
6647 /* Calculates number of iterations for all loops, to ensure that they are
6651 record_numbers_of_iterations (void)
6656 FOR_EACH_LOOP (li, loop, 0)
6658 number_of_latch_executions (loop);
6662 /* Main entry point to VRP (Value Range Propagation). This pass is
6663 loosely based on J. R. C. Patterson, ``Accurate Static Branch
6664 Prediction by Value Range Propagation,'' in SIGPLAN Conference on
6665 Programming Language Design and Implementation, pp. 67-78, 1995.
6666 Also available at http://citeseer.ist.psu.edu/patterson95accurate.html
6668 This is essentially an SSA-CCP pass modified to deal with ranges
6669 instead of constants.
6671 While propagating ranges, we may find that two or more SSA name
6672 have equivalent, though distinct ranges. For instance,
6675 2 p_4 = ASSERT_EXPR <p_3, p_3 != 0>
6677 4 p_5 = ASSERT_EXPR <p_4, p_4 == q_2>;
6681 In the code above, pointer p_5 has range [q_2, q_2], but from the
6682 code we can also determine that p_5 cannot be NULL and, if q_2 had
6683 a non-varying range, p_5's range should also be compatible with it.
6685 These equivalences are created by two expressions: ASSERT_EXPR and
6686 copy operations. Since p_5 is an assertion on p_4, and p_4 was the
6687 result of another assertion, then we can use the fact that p_5 and
6688 p_4 are equivalent when evaluating p_5's range.
6690 Together with value ranges, we also propagate these equivalences
6691 between names so that we can take advantage of information from
6692 multiple ranges when doing final replacement. Note that this
6693 equivalency relation is transitive but not symmetric.
6695 In the example above, p_5 is equivalent to p_4, q_2 and p_3, but we
6696 cannot assert that q_2 is equivalent to p_5 because q_2 may be used
6697 in contexts where that assertion does not hold (e.g., in line 6).
6699 TODO, the main difference between this pass and Patterson's is that
6700 we do not propagate edge probabilities. We only compute whether
6701 edges can be taken or not. That is, instead of having a spectrum
6702 of jump probabilities between 0 and 1, we only deal with 0, 1 and
6703 DON'T KNOW. In the future, it may be worthwhile to propagate
6704 probabilities to aid branch prediction. */
6713 loop_optimizer_init (LOOPS_NORMAL | LOOPS_HAVE_RECORDED_EXITS);
6714 rewrite_into_loop_closed_ssa (NULL, TODO_update_ssa);
6717 insert_range_assertions ();
6719 /* Compute the # of iterations for each loop before we start the VRP
6720 analysis. The value ranges determined by VRP are used in expression
6721 simplification, that is also used by the # of iterations analysis.
6722 However, in the middle of the VRP analysis, the value ranges do not take
6723 all the possible paths in CFG into account, so they do not have to be
6724 correct, and the # of iterations analysis can obtain wrong results.
6725 This is a problem, since the results of the # of iterations analysis
6726 are cached, so these mistakes would not be corrected when the value
6727 ranges are corrected. */
6728 record_numbers_of_iterations ();
6730 to_remove_edges = VEC_alloc (edge, heap, 10);
6731 to_update_switch_stmts = VEC_alloc (switch_update, heap, 5);
6734 ssa_propagate (vrp_visit_stmt, vrp_visit_phi_node);
6737 /* Remove dead edges from SWITCH_EXPR optimization. This leaves the
6738 CFG in a broken state and requires a cfg_cleanup run. */
6739 for (i = 0; VEC_iterate (edge, to_remove_edges, i, e); ++i)
6741 /* Update SWITCH_EXPR case label vector. */
6742 for (i = 0; VEC_iterate (switch_update, to_update_switch_stmts, i, su); ++i)
6743 SWITCH_LABELS (su->stmt) = su->vec;
6745 if (VEC_length (edge, to_remove_edges) > 0)
6746 free_dominance_info (CDI_DOMINATORS);
6748 VEC_free (edge, heap, to_remove_edges);
6749 VEC_free (switch_update, heap, to_update_switch_stmts);
6751 /* ASSERT_EXPRs must be removed before finalizing jump threads
6752 as finalizing jump threads calls the CFG cleanup code which
6753 does not properly handle ASSERT_EXPRs. */
6754 remove_range_assertions ();
6756 /* If we exposed any new variables, go ahead and put them into
6757 SSA form now, before we handle jump threading. This simplifies
6758 interactions between rewriting of _DECL nodes into SSA form
6759 and rewriting SSA_NAME nodes into SSA form after block
6760 duplication and CFG manipulation. */
6761 update_ssa (TODO_update_ssa);
6763 finalize_jump_threads ();
6765 loop_optimizer_finalize ();
6773 return flag_tree_vrp != 0;
6776 struct gimple_opt_pass pass_vrp =
6781 gate_vrp, /* gate */
6782 execute_vrp, /* execute */
6785 0, /* static_pass_number */
6786 TV_TREE_VRP, /* tv_id */
6787 PROP_ssa | PROP_alias, /* properties_required */
6788 0, /* properties_provided */
6789 0, /* properties_destroyed */
6790 0, /* todo_flags_start */
6795 | TODO_update_ssa /* todo_flags_finish */