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;
108 /* Return whether TYPE should use an overflow infinity distinct from
109 TYPE_{MIN,MAX}_VALUE. We use an overflow infinity value to
110 represent a signed overflow during VRP computations. An infinity
111 is distinct from a half-range, which will go from some number to
112 TYPE_{MIN,MAX}_VALUE. */
115 needs_overflow_infinity (const_tree type)
117 return (INTEGRAL_TYPE_P (type)
118 && !TYPE_OVERFLOW_WRAPS (type)
119 /* Integer sub-types never overflow as they are never
120 operands of arithmetic operators. */
121 && !(TREE_TYPE (type) && TREE_TYPE (type) != type));
124 /* Return whether TYPE can support our overflow infinity
125 representation: we use the TREE_OVERFLOW flag, which only exists
126 for constants. If TYPE doesn't support this, we don't optimize
127 cases which would require signed overflow--we drop them to
131 supports_overflow_infinity (const_tree type)
133 #ifdef ENABLE_CHECKING
134 gcc_assert (needs_overflow_infinity (type));
136 return (TYPE_MIN_VALUE (type) != NULL_TREE
137 && CONSTANT_CLASS_P (TYPE_MIN_VALUE (type))
138 && TYPE_MAX_VALUE (type) != NULL_TREE
139 && CONSTANT_CLASS_P (TYPE_MAX_VALUE (type)));
142 /* VAL is the maximum or minimum value of a type. Return a
143 corresponding overflow infinity. */
146 make_overflow_infinity (tree val)
148 #ifdef ENABLE_CHECKING
149 gcc_assert (val != NULL_TREE && CONSTANT_CLASS_P (val));
151 val = copy_node (val);
152 TREE_OVERFLOW (val) = 1;
156 /* Return a negative overflow infinity for TYPE. */
159 negative_overflow_infinity (tree type)
161 #ifdef ENABLE_CHECKING
162 gcc_assert (supports_overflow_infinity (type));
164 return make_overflow_infinity (TYPE_MIN_VALUE (type));
167 /* Return a positive overflow infinity for TYPE. */
170 positive_overflow_infinity (tree type)
172 #ifdef ENABLE_CHECKING
173 gcc_assert (supports_overflow_infinity (type));
175 return make_overflow_infinity (TYPE_MAX_VALUE (type));
178 /* Return whether VAL is a negative overflow infinity. */
181 is_negative_overflow_infinity (const_tree val)
183 return (needs_overflow_infinity (TREE_TYPE (val))
184 && CONSTANT_CLASS_P (val)
185 && TREE_OVERFLOW (val)
186 && operand_equal_p (val, TYPE_MIN_VALUE (TREE_TYPE (val)), 0));
189 /* Return whether VAL is a positive overflow infinity. */
192 is_positive_overflow_infinity (const_tree val)
194 return (needs_overflow_infinity (TREE_TYPE (val))
195 && CONSTANT_CLASS_P (val)
196 && TREE_OVERFLOW (val)
197 && operand_equal_p (val, TYPE_MAX_VALUE (TREE_TYPE (val)), 0));
200 /* Return whether VAL is a positive or negative overflow infinity. */
203 is_overflow_infinity (const_tree val)
205 return (needs_overflow_infinity (TREE_TYPE (val))
206 && CONSTANT_CLASS_P (val)
207 && TREE_OVERFLOW (val)
208 && (operand_equal_p (val, TYPE_MAX_VALUE (TREE_TYPE (val)), 0)
209 || operand_equal_p (val, TYPE_MIN_VALUE (TREE_TYPE (val)), 0)));
212 /* If VAL is now an overflow infinity, return VAL. Otherwise, return
213 the same value with TREE_OVERFLOW clear. This can be used to avoid
214 confusing a regular value with an overflow value. */
217 avoid_overflow_infinity (tree val)
219 if (!is_overflow_infinity (val))
222 if (operand_equal_p (val, TYPE_MAX_VALUE (TREE_TYPE (val)), 0))
223 return TYPE_MAX_VALUE (TREE_TYPE (val));
226 #ifdef ENABLE_CHECKING
227 gcc_assert (operand_equal_p (val, TYPE_MIN_VALUE (TREE_TYPE (val)), 0));
229 return TYPE_MIN_VALUE (TREE_TYPE (val));
234 /* Return whether VAL is equal to the maximum value of its type. This
235 will be true for a positive overflow infinity. We can't do a
236 simple equality comparison with TYPE_MAX_VALUE because C typedefs
237 and Ada subtypes can produce types whose TYPE_MAX_VALUE is not ==
238 to the integer constant with the same value in the type. */
241 vrp_val_is_max (const_tree val)
243 tree type_max, type = TREE_TYPE (val);
245 /* For integer sub-types the values for the base type are relevant. */
246 if (TREE_TYPE (type))
247 type = TREE_TYPE (type);
248 type_max = TYPE_MAX_VALUE (type);
250 return (val == type_max
251 || (type_max != NULL_TREE
252 && operand_equal_p (val, type_max, 0)));
255 /* Return whether VAL is equal to the minimum value of its type. This
256 will be true for a negative overflow infinity. */
259 vrp_val_is_min (const_tree val)
261 tree type_min, type = TREE_TYPE (val);
263 /* For integer sub-types the values for the base type are relevant. */
264 if (TREE_TYPE (type))
265 type = TREE_TYPE (type);
266 type_min = TYPE_MIN_VALUE (type);
268 return (val == type_min
269 || (type_min != NULL_TREE
270 && operand_equal_p (val, type_min, 0)));
274 /* Return true if ARG is marked with the nonnull attribute in the
275 current function signature. */
278 nonnull_arg_p (const_tree arg)
280 tree t, attrs, fntype;
281 unsigned HOST_WIDE_INT arg_num;
283 gcc_assert (TREE_CODE (arg) == PARM_DECL && POINTER_TYPE_P (TREE_TYPE (arg)));
285 /* The static chain decl is always non null. */
286 if (arg == cfun->static_chain_decl)
289 fntype = TREE_TYPE (current_function_decl);
290 attrs = lookup_attribute ("nonnull", TYPE_ATTRIBUTES (fntype));
292 /* If "nonnull" wasn't specified, we know nothing about the argument. */
293 if (attrs == NULL_TREE)
296 /* If "nonnull" applies to all the arguments, then ARG is non-null. */
297 if (TREE_VALUE (attrs) == NULL_TREE)
300 /* Get the position number for ARG in the function signature. */
301 for (arg_num = 1, t = DECL_ARGUMENTS (current_function_decl);
303 t = TREE_CHAIN (t), arg_num++)
309 gcc_assert (t == arg);
311 /* Now see if ARG_NUM is mentioned in the nonnull list. */
312 for (t = TREE_VALUE (attrs); t; t = TREE_CHAIN (t))
314 if (compare_tree_int (TREE_VALUE (t), arg_num) == 0)
322 /* Set value range VR to VR_VARYING. */
325 set_value_range_to_varying (value_range_t *vr)
327 vr->type = VR_VARYING;
328 vr->min = vr->max = NULL_TREE;
330 bitmap_clear (vr->equiv);
334 /* Set value range VR to {T, MIN, MAX, EQUIV}. */
337 set_value_range (value_range_t *vr, enum value_range_type t, tree min,
338 tree max, bitmap equiv)
340 #if defined ENABLE_CHECKING
341 /* Check the validity of the range. */
342 if (t == VR_RANGE || t == VR_ANTI_RANGE)
346 gcc_assert (min && max);
348 if (INTEGRAL_TYPE_P (TREE_TYPE (min)) && t == VR_ANTI_RANGE)
349 gcc_assert (!vrp_val_is_min (min) || !vrp_val_is_max (max));
351 cmp = compare_values (min, max);
352 gcc_assert (cmp == 0 || cmp == -1 || cmp == -2);
354 if (needs_overflow_infinity (TREE_TYPE (min)))
355 gcc_assert (!is_overflow_infinity (min)
356 || !is_overflow_infinity (max));
359 if (t == VR_UNDEFINED || t == VR_VARYING)
360 gcc_assert (min == NULL_TREE && max == NULL_TREE);
362 if (t == VR_UNDEFINED || t == VR_VARYING)
363 gcc_assert (equiv == NULL || bitmap_empty_p (equiv));
370 /* Since updating the equivalence set involves deep copying the
371 bitmaps, only do it if absolutely necessary. */
372 if (vr->equiv == NULL
374 vr->equiv = BITMAP_ALLOC (NULL);
376 if (equiv != vr->equiv)
378 if (equiv && !bitmap_empty_p (equiv))
379 bitmap_copy (vr->equiv, equiv);
381 bitmap_clear (vr->equiv);
386 /* Set value range VR to the canonical form of {T, MIN, MAX, EQUIV}.
387 This means adjusting T, MIN and MAX representing the case of a
388 wrapping range with MAX < MIN covering [MIN, type_max] U [type_min, MAX]
389 as anti-rage ~[MAX+1, MIN-1]. Likewise for wrapping anti-ranges.
390 In corner cases where MAX+1 or MIN-1 wraps this will fall back
392 This routine exists to ease canonicalization in the case where we
393 extract ranges from var + CST op limit. */
396 set_and_canonicalize_value_range (value_range_t *vr, enum value_range_type t,
397 tree min, tree max, bitmap equiv)
402 && t != VR_ANTI_RANGE)
403 || TREE_CODE (min) != INTEGER_CST
404 || TREE_CODE (max) != INTEGER_CST
405 || !tree_int_cst_lt (max, min))
407 set_value_range (vr, t, min, max, equiv);
411 /* Wrong order for min and max, to swap them and the VR type we need
413 one = build_int_cst (TREE_TYPE (min), 1);
414 tmp = int_const_binop (PLUS_EXPR, max, one, 0);
415 max = int_const_binop (MINUS_EXPR, min, one, 0);
418 /* There's one corner case, if we had [C+1, C] before we now have
419 that again. But this represents an empty value range, so drop
420 to varying in this case. */
421 if (tree_int_cst_lt (max, min))
423 set_value_range_to_varying (vr);
427 t = t == VR_RANGE ? VR_ANTI_RANGE : VR_RANGE;
428 set_value_range (vr, t, min, max, equiv);
431 /* Copy value range FROM into value range TO. */
434 copy_value_range (value_range_t *to, value_range_t *from)
436 set_value_range (to, from->type, from->min, from->max, from->equiv);
439 /* Set value range VR to a single value. This function is only called
440 with values we get from statements, and exists to clear the
441 TREE_OVERFLOW flag so that we don't think we have an overflow
442 infinity when we shouldn't. */
445 set_value_range_to_value (value_range_t *vr, tree val, bitmap equiv)
447 gcc_assert (is_gimple_min_invariant (val));
448 val = avoid_overflow_infinity (val);
449 set_value_range (vr, VR_RANGE, val, val, equiv);
452 /* Set value range VR to a non-negative range of type TYPE.
453 OVERFLOW_INFINITY indicates whether to use an overflow infinity
454 rather than TYPE_MAX_VALUE; this should be true if we determine
455 that the range is nonnegative based on the assumption that signed
456 overflow does not occur. */
459 set_value_range_to_nonnegative (value_range_t *vr, tree type,
460 bool overflow_infinity)
464 if (overflow_infinity && !supports_overflow_infinity (type))
466 set_value_range_to_varying (vr);
470 zero = build_int_cst (type, 0);
471 set_value_range (vr, VR_RANGE, zero,
473 ? positive_overflow_infinity (type)
474 : TYPE_MAX_VALUE (type)),
478 /* Set value range VR to a non-NULL range of type TYPE. */
481 set_value_range_to_nonnull (value_range_t *vr, tree type)
483 tree zero = build_int_cst (type, 0);
484 set_value_range (vr, VR_ANTI_RANGE, zero, zero, vr->equiv);
488 /* Set value range VR to a NULL range of type TYPE. */
491 set_value_range_to_null (value_range_t *vr, tree type)
493 set_value_range_to_value (vr, build_int_cst (type, 0), vr->equiv);
497 /* Set value range VR to a range of a truthvalue of type TYPE. */
500 set_value_range_to_truthvalue (value_range_t *vr, tree type)
502 if (TYPE_PRECISION (type) == 1)
503 set_value_range_to_varying (vr);
505 set_value_range (vr, VR_RANGE,
506 build_int_cst (type, 0), build_int_cst (type, 1),
511 /* Set value range VR to VR_UNDEFINED. */
514 set_value_range_to_undefined (value_range_t *vr)
516 vr->type = VR_UNDEFINED;
517 vr->min = vr->max = NULL_TREE;
519 bitmap_clear (vr->equiv);
523 /* Return value range information for VAR.
525 If we have no values ranges recorded (ie, VRP is not running), then
526 return NULL. Otherwise create an empty range if none existed for VAR. */
528 static value_range_t *
529 get_value_range (const_tree var)
533 unsigned ver = SSA_NAME_VERSION (var);
535 /* If we have no recorded ranges, then return NULL. */
543 /* Create a default value range. */
544 vr_value[ver] = vr = XCNEW (value_range_t);
546 /* Defer allocating the equivalence set. */
549 /* If VAR is a default definition, the variable can take any value
551 sym = SSA_NAME_VAR (var);
552 if (SSA_NAME_IS_DEFAULT_DEF (var))
554 /* Try to use the "nonnull" attribute to create ~[0, 0]
555 anti-ranges for pointers. Note that this is only valid with
556 default definitions of PARM_DECLs. */
557 if (TREE_CODE (sym) == PARM_DECL
558 && POINTER_TYPE_P (TREE_TYPE (sym))
559 && nonnull_arg_p (sym))
560 set_value_range_to_nonnull (vr, TREE_TYPE (sym));
562 set_value_range_to_varying (vr);
568 /* Return true, if VAL1 and VAL2 are equal values for VRP purposes. */
571 vrp_operand_equal_p (const_tree val1, const_tree val2)
575 if (!val1 || !val2 || !operand_equal_p (val1, val2, 0))
577 if (is_overflow_infinity (val1))
578 return is_overflow_infinity (val2);
582 /* Return true, if the bitmaps B1 and B2 are equal. */
585 vrp_bitmap_equal_p (const_bitmap b1, const_bitmap b2)
589 && bitmap_equal_p (b1, b2)));
592 /* Update the value range and equivalence set for variable VAR to
593 NEW_VR. Return true if NEW_VR is different from VAR's previous
596 NOTE: This function assumes that NEW_VR is a temporary value range
597 object created for the sole purpose of updating VAR's range. The
598 storage used by the equivalence set from NEW_VR will be freed by
599 this function. Do not call update_value_range when NEW_VR
600 is the range object associated with another SSA name. */
603 update_value_range (const_tree var, value_range_t *new_vr)
605 value_range_t *old_vr;
608 /* Update the value range, if necessary. */
609 old_vr = get_value_range (var);
610 is_new = old_vr->type != new_vr->type
611 || !vrp_operand_equal_p (old_vr->min, new_vr->min)
612 || !vrp_operand_equal_p (old_vr->max, new_vr->max)
613 || !vrp_bitmap_equal_p (old_vr->equiv, new_vr->equiv);
616 set_value_range (old_vr, new_vr->type, new_vr->min, new_vr->max,
619 BITMAP_FREE (new_vr->equiv);
625 /* Add VAR and VAR's equivalence set to EQUIV. This is the central
626 point where equivalence processing can be turned on/off. */
629 add_equivalence (bitmap *equiv, const_tree var)
631 unsigned ver = SSA_NAME_VERSION (var);
632 value_range_t *vr = vr_value[ver];
635 *equiv = BITMAP_ALLOC (NULL);
636 bitmap_set_bit (*equiv, ver);
638 bitmap_ior_into (*equiv, vr->equiv);
642 /* Return true if VR is ~[0, 0]. */
645 range_is_nonnull (value_range_t *vr)
647 return vr->type == VR_ANTI_RANGE
648 && integer_zerop (vr->min)
649 && integer_zerop (vr->max);
653 /* Return true if VR is [0, 0]. */
656 range_is_null (value_range_t *vr)
658 return vr->type == VR_RANGE
659 && integer_zerop (vr->min)
660 && integer_zerop (vr->max);
664 /* Return true if value range VR involves at least one symbol. */
667 symbolic_range_p (value_range_t *vr)
669 return (!is_gimple_min_invariant (vr->min)
670 || !is_gimple_min_invariant (vr->max));
673 /* Return true if value range VR uses an overflow infinity. */
676 overflow_infinity_range_p (value_range_t *vr)
678 return (vr->type == VR_RANGE
679 && (is_overflow_infinity (vr->min)
680 || is_overflow_infinity (vr->max)));
683 /* Return false if we can not make a valid comparison based on VR;
684 this will be the case if it uses an overflow infinity and overflow
685 is not undefined (i.e., -fno-strict-overflow is in effect).
686 Otherwise return true, and set *STRICT_OVERFLOW_P to true if VR
687 uses an overflow infinity. */
690 usable_range_p (value_range_t *vr, bool *strict_overflow_p)
692 gcc_assert (vr->type == VR_RANGE);
693 if (is_overflow_infinity (vr->min))
695 *strict_overflow_p = true;
696 if (!TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (vr->min)))
699 if (is_overflow_infinity (vr->max))
701 *strict_overflow_p = true;
702 if (!TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (vr->max)))
709 /* Like tree_expr_nonnegative_warnv_p, but this function uses value
710 ranges obtained so far. */
713 vrp_expr_computes_nonnegative (tree expr, bool *strict_overflow_p)
715 return tree_expr_nonnegative_warnv_p (expr, strict_overflow_p);
718 /* Like tree_expr_nonzero_warnv_p, but this function uses value ranges
722 vrp_expr_computes_nonzero (tree expr, bool *strict_overflow_p)
724 if (tree_expr_nonzero_warnv_p (expr, strict_overflow_p))
727 /* If we have an expression of the form &X->a, then the expression
728 is nonnull if X is nonnull. */
729 if (TREE_CODE (expr) == ADDR_EXPR)
731 tree base = get_base_address (TREE_OPERAND (expr, 0));
733 if (base != NULL_TREE
734 && TREE_CODE (base) == INDIRECT_REF
735 && TREE_CODE (TREE_OPERAND (base, 0)) == SSA_NAME)
737 value_range_t *vr = get_value_range (TREE_OPERAND (base, 0));
738 if (range_is_nonnull (vr))
746 /* Returns true if EXPR is a valid value (as expected by compare_values) --
747 a gimple invariant, or SSA_NAME +- CST. */
750 valid_value_p (tree expr)
752 if (TREE_CODE (expr) == SSA_NAME)
755 if (TREE_CODE (expr) == PLUS_EXPR
756 || TREE_CODE (expr) == MINUS_EXPR)
757 return (TREE_CODE (TREE_OPERAND (expr, 0)) == SSA_NAME
758 && TREE_CODE (TREE_OPERAND (expr, 1)) == INTEGER_CST);
760 return is_gimple_min_invariant (expr);
766 -2 if those are incomparable. */
768 operand_less_p (tree val, tree val2)
770 /* LT is folded faster than GE and others. Inline the common case. */
771 if (TREE_CODE (val) == INTEGER_CST && TREE_CODE (val2) == INTEGER_CST)
773 if (TYPE_UNSIGNED (TREE_TYPE (val)))
774 return INT_CST_LT_UNSIGNED (val, val2);
777 if (INT_CST_LT (val, val2))
785 fold_defer_overflow_warnings ();
787 tcmp = fold_binary_to_constant (LT_EXPR, boolean_type_node, val, val2);
789 fold_undefer_and_ignore_overflow_warnings ();
792 || TREE_CODE (tcmp) != INTEGER_CST)
795 if (!integer_zerop (tcmp))
799 /* val >= val2, not considering overflow infinity. */
800 if (is_negative_overflow_infinity (val))
801 return is_negative_overflow_infinity (val2) ? 0 : 1;
802 else if (is_positive_overflow_infinity (val2))
803 return is_positive_overflow_infinity (val) ? 0 : 1;
808 /* Compare two values VAL1 and VAL2. Return
810 -2 if VAL1 and VAL2 cannot be compared at compile-time,
813 +1 if VAL1 > VAL2, and
816 This is similar to tree_int_cst_compare but supports pointer values
817 and values that cannot be compared at compile time.
819 If STRICT_OVERFLOW_P is not NULL, then set *STRICT_OVERFLOW_P to
820 true if the return value is only valid if we assume that signed
821 overflow is undefined. */
824 compare_values_warnv (tree val1, tree val2, bool *strict_overflow_p)
829 /* Below we rely on the fact that VAL1 and VAL2 are both pointers or
831 gcc_assert (POINTER_TYPE_P (TREE_TYPE (val1))
832 == POINTER_TYPE_P (TREE_TYPE (val2)));
833 /* Convert the two values into the same type. This is needed because
834 sizetype causes sign extension even for unsigned types. */
835 val2 = fold_convert (TREE_TYPE (val1), val2);
836 STRIP_USELESS_TYPE_CONVERSION (val2);
838 if ((TREE_CODE (val1) == SSA_NAME
839 || TREE_CODE (val1) == PLUS_EXPR
840 || TREE_CODE (val1) == MINUS_EXPR)
841 && (TREE_CODE (val2) == SSA_NAME
842 || TREE_CODE (val2) == PLUS_EXPR
843 || TREE_CODE (val2) == MINUS_EXPR))
846 enum tree_code code1, code2;
848 /* If VAL1 and VAL2 are of the form 'NAME [+-] CST' or 'NAME',
849 return -1 or +1 accordingly. If VAL1 and VAL2 don't use the
850 same name, return -2. */
851 if (TREE_CODE (val1) == SSA_NAME)
859 code1 = TREE_CODE (val1);
860 n1 = TREE_OPERAND (val1, 0);
861 c1 = TREE_OPERAND (val1, 1);
862 if (tree_int_cst_sgn (c1) == -1)
864 if (is_negative_overflow_infinity (c1))
866 c1 = fold_unary_to_constant (NEGATE_EXPR, TREE_TYPE (c1), c1);
869 code1 = code1 == MINUS_EXPR ? PLUS_EXPR : MINUS_EXPR;
873 if (TREE_CODE (val2) == SSA_NAME)
881 code2 = TREE_CODE (val2);
882 n2 = TREE_OPERAND (val2, 0);
883 c2 = TREE_OPERAND (val2, 1);
884 if (tree_int_cst_sgn (c2) == -1)
886 if (is_negative_overflow_infinity (c2))
888 c2 = fold_unary_to_constant (NEGATE_EXPR, TREE_TYPE (c2), c2);
891 code2 = code2 == MINUS_EXPR ? PLUS_EXPR : MINUS_EXPR;
895 /* Both values must use the same name. */
899 if (code1 == SSA_NAME
900 && code2 == SSA_NAME)
904 /* If overflow is defined we cannot simplify more. */
905 if (!TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (val1)))
908 if (strict_overflow_p != NULL
909 && (code1 == SSA_NAME || !TREE_NO_WARNING (val1))
910 && (code2 == SSA_NAME || !TREE_NO_WARNING (val2)))
911 *strict_overflow_p = true;
913 if (code1 == SSA_NAME)
915 if (code2 == PLUS_EXPR)
916 /* NAME < NAME + CST */
918 else if (code2 == MINUS_EXPR)
919 /* NAME > NAME - CST */
922 else if (code1 == PLUS_EXPR)
924 if (code2 == SSA_NAME)
925 /* NAME + CST > NAME */
927 else if (code2 == PLUS_EXPR)
928 /* NAME + CST1 > NAME + CST2, if CST1 > CST2 */
929 return compare_values_warnv (c1, c2, strict_overflow_p);
930 else if (code2 == MINUS_EXPR)
931 /* NAME + CST1 > NAME - CST2 */
934 else if (code1 == MINUS_EXPR)
936 if (code2 == SSA_NAME)
937 /* NAME - CST < NAME */
939 else if (code2 == PLUS_EXPR)
940 /* NAME - CST1 < NAME + CST2 */
942 else if (code2 == MINUS_EXPR)
943 /* NAME - CST1 > NAME - CST2, if CST1 < CST2. Notice that
944 C1 and C2 are swapped in the call to compare_values. */
945 return compare_values_warnv (c2, c1, strict_overflow_p);
951 /* We cannot compare non-constants. */
952 if (!is_gimple_min_invariant (val1) || !is_gimple_min_invariant (val2))
955 if (!POINTER_TYPE_P (TREE_TYPE (val1)))
957 /* We cannot compare overflowed values, except for overflow
959 if (TREE_OVERFLOW (val1) || TREE_OVERFLOW (val2))
961 if (strict_overflow_p != NULL)
962 *strict_overflow_p = true;
963 if (is_negative_overflow_infinity (val1))
964 return is_negative_overflow_infinity (val2) ? 0 : -1;
965 else if (is_negative_overflow_infinity (val2))
967 else if (is_positive_overflow_infinity (val1))
968 return is_positive_overflow_infinity (val2) ? 0 : 1;
969 else if (is_positive_overflow_infinity (val2))
974 return tree_int_cst_compare (val1, val2);
980 /* First see if VAL1 and VAL2 are not the same. */
981 if (val1 == val2 || operand_equal_p (val1, val2, 0))
984 /* If VAL1 is a lower address than VAL2, return -1. */
985 if (operand_less_p (val1, val2) == 1)
988 /* If VAL1 is a higher address than VAL2, return +1. */
989 if (operand_less_p (val2, val1) == 1)
992 /* If VAL1 is different than VAL2, return +2.
993 For integer constants we either have already returned -1 or 1
994 or they are equivalent. We still might succeed in proving
995 something about non-trivial operands. */
996 if (TREE_CODE (val1) != INTEGER_CST
997 || TREE_CODE (val2) != INTEGER_CST)
999 t = fold_binary_to_constant (NE_EXPR, boolean_type_node, val1, val2);
1000 if (t && integer_onep (t))
1008 /* Compare values like compare_values_warnv, but treat comparisons of
1009 nonconstants which rely on undefined overflow as incomparable. */
1012 compare_values (tree val1, tree val2)
1018 ret = compare_values_warnv (val1, val2, &sop);
1020 && (!is_gimple_min_invariant (val1) || !is_gimple_min_invariant (val2)))
1026 /* Return 1 if VAL is inside value range VR (VR->MIN <= VAL <= VR->MAX),
1027 0 if VAL is not inside VR,
1028 -2 if we cannot tell either way.
1030 FIXME, the current semantics of this functions are a bit quirky
1031 when taken in the context of VRP. In here we do not care
1032 about VR's type. If VR is the anti-range ~[3, 5] the call
1033 value_inside_range (4, VR) will return 1.
1035 This is counter-intuitive in a strict sense, but the callers
1036 currently expect this. They are calling the function
1037 merely to determine whether VR->MIN <= VAL <= VR->MAX. The
1038 callers are applying the VR_RANGE/VR_ANTI_RANGE semantics
1041 This also applies to value_ranges_intersect_p and
1042 range_includes_zero_p. The semantics of VR_RANGE and
1043 VR_ANTI_RANGE should be encoded here, but that also means
1044 adapting the users of these functions to the new semantics.
1046 Benchmark compile/20001226-1.c compilation time after changing this
1050 value_inside_range (tree val, value_range_t * vr)
1054 cmp1 = operand_less_p (val, vr->min);
1060 cmp2 = operand_less_p (vr->max, val);
1068 /* Return true if value ranges VR0 and VR1 have a non-empty
1071 Benchmark compile/20001226-1.c compilation time after changing this
1076 value_ranges_intersect_p (value_range_t *vr0, value_range_t *vr1)
1078 /* The value ranges do not intersect if the maximum of the first range is
1079 less than the minimum of the second range or vice versa.
1080 When those relations are unknown, we can't do any better. */
1081 if (operand_less_p (vr0->max, vr1->min) != 0)
1083 if (operand_less_p (vr1->max, vr0->min) != 0)
1089 /* Return true if VR includes the value zero, false otherwise. FIXME,
1090 currently this will return false for an anti-range like ~[-4, 3].
1091 This will be wrong when the semantics of value_inside_range are
1092 modified (currently the users of this function expect these
1096 range_includes_zero_p (value_range_t *vr)
1100 gcc_assert (vr->type != VR_UNDEFINED
1101 && vr->type != VR_VARYING
1102 && !symbolic_range_p (vr));
1104 zero = build_int_cst (TREE_TYPE (vr->min), 0);
1105 return (value_inside_range (zero, vr) == 1);
1108 /* Return true if T, an SSA_NAME, is known to be nonnegative. Return
1109 false otherwise or if no value range information is available. */
1112 ssa_name_nonnegative_p (const_tree t)
1114 value_range_t *vr = get_value_range (t);
1119 /* Testing for VR_ANTI_RANGE is not useful here as any anti-range
1120 which would return a useful value should be encoded as a VR_RANGE. */
1121 if (vr->type == VR_RANGE)
1123 int result = compare_values (vr->min, integer_zero_node);
1125 return (result == 0 || result == 1);
1130 /* Return true if T, an SSA_NAME, is known to be nonzero. Return
1131 false otherwise or if no value range information is available. */
1134 ssa_name_nonzero_p (const_tree t)
1136 value_range_t *vr = get_value_range (t);
1141 /* A VR_RANGE which does not include zero is a nonzero value. */
1142 if (vr->type == VR_RANGE && !symbolic_range_p (vr))
1143 return ! range_includes_zero_p (vr);
1145 /* A VR_ANTI_RANGE which does include zero is a nonzero value. */
1146 if (vr->type == VR_ANTI_RANGE && !symbolic_range_p (vr))
1147 return range_includes_zero_p (vr);
1153 /* Extract value range information from an ASSERT_EXPR EXPR and store
1157 extract_range_from_assert (value_range_t *vr_p, tree expr)
1159 tree var, cond, limit, min, max, type;
1160 value_range_t *var_vr, *limit_vr;
1161 enum tree_code cond_code;
1163 var = ASSERT_EXPR_VAR (expr);
1164 cond = ASSERT_EXPR_COND (expr);
1166 gcc_assert (COMPARISON_CLASS_P (cond));
1168 /* Find VAR in the ASSERT_EXPR conditional. */
1169 if (var == TREE_OPERAND (cond, 0)
1170 || TREE_CODE (TREE_OPERAND (cond, 0)) == PLUS_EXPR
1171 || TREE_CODE (TREE_OPERAND (cond, 0)) == NOP_EXPR)
1173 /* If the predicate is of the form VAR COMP LIMIT, then we just
1174 take LIMIT from the RHS and use the same comparison code. */
1175 cond_code = TREE_CODE (cond);
1176 limit = TREE_OPERAND (cond, 1);
1177 cond = TREE_OPERAND (cond, 0);
1181 /* If the predicate is of the form LIMIT COMP VAR, then we need
1182 to flip around the comparison code to create the proper range
1184 cond_code = swap_tree_comparison (TREE_CODE (cond));
1185 limit = TREE_OPERAND (cond, 0);
1186 cond = TREE_OPERAND (cond, 1);
1189 limit = avoid_overflow_infinity (limit);
1191 type = TREE_TYPE (limit);
1192 gcc_assert (limit != var);
1194 /* For pointer arithmetic, we only keep track of pointer equality
1196 if (POINTER_TYPE_P (type) && cond_code != NE_EXPR && cond_code != EQ_EXPR)
1198 set_value_range_to_varying (vr_p);
1202 /* If LIMIT is another SSA name and LIMIT has a range of its own,
1203 try to use LIMIT's range to avoid creating symbolic ranges
1205 limit_vr = (TREE_CODE (limit) == SSA_NAME) ? get_value_range (limit) : NULL;
1207 /* LIMIT's range is only interesting if it has any useful information. */
1209 && (limit_vr->type == VR_UNDEFINED
1210 || limit_vr->type == VR_VARYING
1211 || symbolic_range_p (limit_vr)))
1214 /* Initially, the new range has the same set of equivalences of
1215 VAR's range. This will be revised before returning the final
1216 value. Since assertions may be chained via mutually exclusive
1217 predicates, we will need to trim the set of equivalences before
1219 gcc_assert (vr_p->equiv == NULL);
1220 add_equivalence (&vr_p->equiv, var);
1222 /* Extract a new range based on the asserted comparison for VAR and
1223 LIMIT's value range. Notice that if LIMIT has an anti-range, we
1224 will only use it for equality comparisons (EQ_EXPR). For any
1225 other kind of assertion, we cannot derive a range from LIMIT's
1226 anti-range that can be used to describe the new range. For
1227 instance, ASSERT_EXPR <x_2, x_2 <= b_4>. If b_4 is ~[2, 10],
1228 then b_4 takes on the ranges [-INF, 1] and [11, +INF]. There is
1229 no single range for x_2 that could describe LE_EXPR, so we might
1230 as well build the range [b_4, +INF] for it.
1231 One special case we handle is extracting a range from a
1232 range test encoded as (unsigned)var + CST <= limit. */
1233 if (TREE_CODE (cond) == NOP_EXPR
1234 || TREE_CODE (cond) == PLUS_EXPR)
1236 tree cst2 = NULL_TREE;
1238 if (TREE_CODE (cond) == PLUS_EXPR)
1240 min = TREE_OPERAND (cond, 1);
1241 cst2 = fold_build1 (NEGATE_EXPR, TREE_TYPE (min), min);
1242 min = fold_convert (TREE_TYPE (var), cst2);
1243 cond = TREE_OPERAND (cond, 0);
1246 min = build_int_cst (TREE_TYPE (var), 0);
1248 if (cst2 != NULL_TREE)
1249 max = int_const_binop (PLUS_EXPR, limit, min, 0);
1252 max = fold_convert (TREE_TYPE (var), max);
1254 /* We can transform a max, min range to an anti-range or
1255 vice-versa. Use set_and_canonicalize_value_range which does
1257 if (cond_code == LE_EXPR)
1258 set_and_canonicalize_value_range (vr_p, VR_RANGE,
1259 min, max, vr_p->equiv);
1260 else if (cond_code == GT_EXPR)
1261 set_and_canonicalize_value_range (vr_p, VR_ANTI_RANGE,
1262 min, max, vr_p->equiv);
1266 else if (cond_code == EQ_EXPR)
1268 enum value_range_type range_type;
1272 range_type = limit_vr->type;
1273 min = limit_vr->min;
1274 max = limit_vr->max;
1278 range_type = VR_RANGE;
1283 set_value_range (vr_p, range_type, min, max, vr_p->equiv);
1285 /* When asserting the equality VAR == LIMIT and LIMIT is another
1286 SSA name, the new range will also inherit the equivalence set
1288 if (TREE_CODE (limit) == SSA_NAME)
1289 add_equivalence (&vr_p->equiv, limit);
1291 else if (cond_code == NE_EXPR)
1293 /* As described above, when LIMIT's range is an anti-range and
1294 this assertion is an inequality (NE_EXPR), then we cannot
1295 derive anything from the anti-range. For instance, if
1296 LIMIT's range was ~[0, 0], the assertion 'VAR != LIMIT' does
1297 not imply that VAR's range is [0, 0]. So, in the case of
1298 anti-ranges, we just assert the inequality using LIMIT and
1301 If LIMIT_VR is a range, we can only use it to build a new
1302 anti-range if LIMIT_VR is a single-valued range. For
1303 instance, if LIMIT_VR is [0, 1], the predicate
1304 VAR != [0, 1] does not mean that VAR's range is ~[0, 1].
1305 Rather, it means that for value 0 VAR should be ~[0, 0]
1306 and for value 1, VAR should be ~[1, 1]. We cannot
1307 represent these ranges.
1309 The only situation in which we can build a valid
1310 anti-range is when LIMIT_VR is a single-valued range
1311 (i.e., LIMIT_VR->MIN == LIMIT_VR->MAX). In that case,
1312 build the anti-range ~[LIMIT_VR->MIN, LIMIT_VR->MAX]. */
1314 && limit_vr->type == VR_RANGE
1315 && compare_values (limit_vr->min, limit_vr->max) == 0)
1317 min = limit_vr->min;
1318 max = limit_vr->max;
1322 /* In any other case, we cannot use LIMIT's range to build a
1323 valid anti-range. */
1327 /* If MIN and MAX cover the whole range for their type, then
1328 just use the original LIMIT. */
1329 if (INTEGRAL_TYPE_P (type)
1330 && vrp_val_is_min (min)
1331 && vrp_val_is_max (max))
1334 set_value_range (vr_p, VR_ANTI_RANGE, min, max, vr_p->equiv);
1336 else if (cond_code == LE_EXPR || cond_code == LT_EXPR)
1338 min = TYPE_MIN_VALUE (type);
1340 if (limit_vr == NULL || limit_vr->type == VR_ANTI_RANGE)
1344 /* If LIMIT_VR is of the form [N1, N2], we need to build the
1345 range [MIN, N2] for LE_EXPR and [MIN, N2 - 1] for
1347 max = limit_vr->max;
1350 /* If the maximum value forces us to be out of bounds, simply punt.
1351 It would be pointless to try and do anything more since this
1352 all should be optimized away above us. */
1353 if ((cond_code == LT_EXPR
1354 && compare_values (max, min) == 0)
1355 || is_overflow_infinity (max))
1356 set_value_range_to_varying (vr_p);
1359 /* For LT_EXPR, we create the range [MIN, MAX - 1]. */
1360 if (cond_code == LT_EXPR)
1362 tree one = build_int_cst (type, 1);
1363 max = fold_build2 (MINUS_EXPR, type, max, one);
1365 TREE_NO_WARNING (max) = 1;
1368 set_value_range (vr_p, VR_RANGE, min, max, vr_p->equiv);
1371 else if (cond_code == GE_EXPR || cond_code == GT_EXPR)
1373 max = TYPE_MAX_VALUE (type);
1375 if (limit_vr == NULL || limit_vr->type == VR_ANTI_RANGE)
1379 /* If LIMIT_VR is of the form [N1, N2], we need to build the
1380 range [N1, MAX] for GE_EXPR and [N1 + 1, MAX] for
1382 min = limit_vr->min;
1385 /* If the minimum value forces us to be out of bounds, simply punt.
1386 It would be pointless to try and do anything more since this
1387 all should be optimized away above us. */
1388 if ((cond_code == GT_EXPR
1389 && compare_values (min, max) == 0)
1390 || is_overflow_infinity (min))
1391 set_value_range_to_varying (vr_p);
1394 /* For GT_EXPR, we create the range [MIN + 1, MAX]. */
1395 if (cond_code == GT_EXPR)
1397 tree one = build_int_cst (type, 1);
1398 min = fold_build2 (PLUS_EXPR, type, min, one);
1400 TREE_NO_WARNING (min) = 1;
1403 set_value_range (vr_p, VR_RANGE, min, max, vr_p->equiv);
1409 /* If VAR already had a known range, it may happen that the new
1410 range we have computed and VAR's range are not compatible. For
1414 p_6 = ASSERT_EXPR <p_5, p_5 == NULL>;
1416 p_8 = ASSERT_EXPR <p_6, p_6 != NULL>;
1418 While the above comes from a faulty program, it will cause an ICE
1419 later because p_8 and p_6 will have incompatible ranges and at
1420 the same time will be considered equivalent. A similar situation
1424 i_6 = ASSERT_EXPR <i_5, i_5 > 10>;
1426 i_7 = ASSERT_EXPR <i_6, i_6 < 5>;
1428 Again i_6 and i_7 will have incompatible ranges. It would be
1429 pointless to try and do anything with i_7's range because
1430 anything dominated by 'if (i_5 < 5)' will be optimized away.
1431 Note, due to the wa in which simulation proceeds, the statement
1432 i_7 = ASSERT_EXPR <...> we would never be visited because the
1433 conditional 'if (i_5 < 5)' always evaluates to false. However,
1434 this extra check does not hurt and may protect against future
1435 changes to VRP that may get into a situation similar to the
1436 NULL pointer dereference example.
1438 Note that these compatibility tests are only needed when dealing
1439 with ranges or a mix of range and anti-range. If VAR_VR and VR_P
1440 are both anti-ranges, they will always be compatible, because two
1441 anti-ranges will always have a non-empty intersection. */
1443 var_vr = get_value_range (var);
1445 /* We may need to make adjustments when VR_P and VAR_VR are numeric
1446 ranges or anti-ranges. */
1447 if (vr_p->type == VR_VARYING
1448 || vr_p->type == VR_UNDEFINED
1449 || var_vr->type == VR_VARYING
1450 || var_vr->type == VR_UNDEFINED
1451 || symbolic_range_p (vr_p)
1452 || symbolic_range_p (var_vr))
1455 if (var_vr->type == VR_RANGE && vr_p->type == VR_RANGE)
1457 /* If the two ranges have a non-empty intersection, we can
1458 refine the resulting range. Since the assert expression
1459 creates an equivalency and at the same time it asserts a
1460 predicate, we can take the intersection of the two ranges to
1461 get better precision. */
1462 if (value_ranges_intersect_p (var_vr, vr_p))
1464 /* Use the larger of the two minimums. */
1465 if (compare_values (vr_p->min, var_vr->min) == -1)
1470 /* Use the smaller of the two maximums. */
1471 if (compare_values (vr_p->max, var_vr->max) == 1)
1476 set_value_range (vr_p, vr_p->type, min, max, vr_p->equiv);
1480 /* The two ranges do not intersect, set the new range to
1481 VARYING, because we will not be able to do anything
1482 meaningful with it. */
1483 set_value_range_to_varying (vr_p);
1486 else if ((var_vr->type == VR_RANGE && vr_p->type == VR_ANTI_RANGE)
1487 || (var_vr->type == VR_ANTI_RANGE && vr_p->type == VR_RANGE))
1489 /* A range and an anti-range will cancel each other only if
1490 their ends are the same. For instance, in the example above,
1491 p_8's range ~[0, 0] and p_6's range [0, 0] are incompatible,
1492 so VR_P should be set to VR_VARYING. */
1493 if (compare_values (var_vr->min, vr_p->min) == 0
1494 && compare_values (var_vr->max, vr_p->max) == 0)
1495 set_value_range_to_varying (vr_p);
1498 tree min, max, anti_min, anti_max, real_min, real_max;
1501 /* We want to compute the logical AND of the two ranges;
1502 there are three cases to consider.
1505 1. The VR_ANTI_RANGE range is completely within the
1506 VR_RANGE and the endpoints of the ranges are
1507 different. In that case the resulting range
1508 should be whichever range is more precise.
1509 Typically that will be the VR_RANGE.
1511 2. The VR_ANTI_RANGE is completely disjoint from
1512 the VR_RANGE. In this case the resulting range
1513 should be the VR_RANGE.
1515 3. There is some overlap between the VR_ANTI_RANGE
1518 3a. If the high limit of the VR_ANTI_RANGE resides
1519 within the VR_RANGE, then the result is a new
1520 VR_RANGE starting at the high limit of the
1521 the VR_ANTI_RANGE + 1 and extending to the
1522 high limit of the original VR_RANGE.
1524 3b. If the low limit of the VR_ANTI_RANGE resides
1525 within the VR_RANGE, then the result is a new
1526 VR_RANGE starting at the low limit of the original
1527 VR_RANGE and extending to the low limit of the
1528 VR_ANTI_RANGE - 1. */
1529 if (vr_p->type == VR_ANTI_RANGE)
1531 anti_min = vr_p->min;
1532 anti_max = vr_p->max;
1533 real_min = var_vr->min;
1534 real_max = var_vr->max;
1538 anti_min = var_vr->min;
1539 anti_max = var_vr->max;
1540 real_min = vr_p->min;
1541 real_max = vr_p->max;
1545 /* Case 1, VR_ANTI_RANGE completely within VR_RANGE,
1546 not including any endpoints. */
1547 if (compare_values (anti_max, real_max) == -1
1548 && compare_values (anti_min, real_min) == 1)
1550 set_value_range (vr_p, VR_RANGE, real_min,
1551 real_max, vr_p->equiv);
1553 /* Case 2, VR_ANTI_RANGE completely disjoint from
1555 else if (compare_values (anti_min, real_max) == 1
1556 || compare_values (anti_max, real_min) == -1)
1558 set_value_range (vr_p, VR_RANGE, real_min,
1559 real_max, vr_p->equiv);
1561 /* Case 3a, the anti-range extends into the low
1562 part of the real range. Thus creating a new
1563 low for the real range. */
1564 else if (((cmp = compare_values (anti_max, real_min)) == 1
1566 && compare_values (anti_max, real_max) == -1)
1568 gcc_assert (!is_positive_overflow_infinity (anti_max));
1569 if (needs_overflow_infinity (TREE_TYPE (anti_max))
1570 && vrp_val_is_max (anti_max))
1572 if (!supports_overflow_infinity (TREE_TYPE (var_vr->min)))
1574 set_value_range_to_varying (vr_p);
1577 min = positive_overflow_infinity (TREE_TYPE (var_vr->min));
1579 else if (!POINTER_TYPE_P (TREE_TYPE (var_vr->min)))
1580 min = fold_build2 (PLUS_EXPR, TREE_TYPE (var_vr->min),
1582 build_int_cst (TREE_TYPE (var_vr->min), 1));
1584 min = fold_build2 (POINTER_PLUS_EXPR, TREE_TYPE (var_vr->min),
1585 anti_max, size_int (1));
1587 set_value_range (vr_p, VR_RANGE, min, max, vr_p->equiv);
1589 /* Case 3b, the anti-range extends into the high
1590 part of the real range. Thus creating a new
1591 higher for the real range. */
1592 else if (compare_values (anti_min, real_min) == 1
1593 && ((cmp = compare_values (anti_min, real_max)) == -1
1596 gcc_assert (!is_negative_overflow_infinity (anti_min));
1597 if (needs_overflow_infinity (TREE_TYPE (anti_min))
1598 && vrp_val_is_min (anti_min))
1600 if (!supports_overflow_infinity (TREE_TYPE (var_vr->min)))
1602 set_value_range_to_varying (vr_p);
1605 max = negative_overflow_infinity (TREE_TYPE (var_vr->min));
1607 else if (!POINTER_TYPE_P (TREE_TYPE (var_vr->min)))
1608 max = fold_build2 (MINUS_EXPR, TREE_TYPE (var_vr->min),
1610 build_int_cst (TREE_TYPE (var_vr->min), 1));
1612 max = fold_build2 (POINTER_PLUS_EXPR, TREE_TYPE (var_vr->min),
1616 set_value_range (vr_p, VR_RANGE, min, max, vr_p->equiv);
1623 /* Extract range information from SSA name VAR and store it in VR. If
1624 VAR has an interesting range, use it. Otherwise, create the
1625 range [VAR, VAR] and return it. This is useful in situations where
1626 we may have conditionals testing values of VARYING names. For
1633 Even if y_5 is deemed VARYING, we can determine that x_3 > y_5 is
1637 extract_range_from_ssa_name (value_range_t *vr, tree var)
1639 value_range_t *var_vr = get_value_range (var);
1641 if (var_vr->type != VR_UNDEFINED && var_vr->type != VR_VARYING)
1642 copy_value_range (vr, var_vr);
1644 set_value_range (vr, VR_RANGE, var, var, NULL);
1646 add_equivalence (&vr->equiv, var);
1650 /* Wrapper around int_const_binop. If the operation overflows and we
1651 are not using wrapping arithmetic, then adjust the result to be
1652 -INF or +INF depending on CODE, VAL1 and VAL2. This can return
1653 NULL_TREE if we need to use an overflow infinity representation but
1654 the type does not support it. */
1657 vrp_int_const_binop (enum tree_code code, tree val1, tree val2)
1661 res = int_const_binop (code, val1, val2, 0);
1663 /* If we are not using wrapping arithmetic, operate symbolically
1664 on -INF and +INF. */
1665 if (TYPE_OVERFLOW_WRAPS (TREE_TYPE (val1)))
1667 int checkz = compare_values (res, val1);
1668 bool overflow = false;
1670 /* Ensure that res = val1 [+*] val2 >= val1
1671 or that res = val1 - val2 <= val1. */
1672 if ((code == PLUS_EXPR
1673 && !(checkz == 1 || checkz == 0))
1674 || (code == MINUS_EXPR
1675 && !(checkz == 0 || checkz == -1)))
1679 /* Checking for multiplication overflow is done by dividing the
1680 output of the multiplication by the first input of the
1681 multiplication. If the result of that division operation is
1682 not equal to the second input of the multiplication, then the
1683 multiplication overflowed. */
1684 else if (code == MULT_EXPR && !integer_zerop (val1))
1686 tree tmp = int_const_binop (TRUNC_DIV_EXPR,
1689 int check = compare_values (tmp, val2);
1697 res = copy_node (res);
1698 TREE_OVERFLOW (res) = 1;
1702 else if ((TREE_OVERFLOW (res)
1703 && !TREE_OVERFLOW (val1)
1704 && !TREE_OVERFLOW (val2))
1705 || is_overflow_infinity (val1)
1706 || is_overflow_infinity (val2))
1708 /* If the operation overflowed but neither VAL1 nor VAL2 are
1709 overflown, return -INF or +INF depending on the operation
1710 and the combination of signs of the operands. */
1711 int sgn1 = tree_int_cst_sgn (val1);
1712 int sgn2 = tree_int_cst_sgn (val2);
1714 if (needs_overflow_infinity (TREE_TYPE (res))
1715 && !supports_overflow_infinity (TREE_TYPE (res)))
1718 /* We have to punt on adding infinities of different signs,
1719 since we can't tell what the sign of the result should be.
1720 Likewise for subtracting infinities of the same sign. */
1721 if (((code == PLUS_EXPR && sgn1 != sgn2)
1722 || (code == MINUS_EXPR && sgn1 == sgn2))
1723 && is_overflow_infinity (val1)
1724 && is_overflow_infinity (val2))
1727 /* Don't try to handle division or shifting of infinities. */
1728 if ((code == TRUNC_DIV_EXPR
1729 || code == FLOOR_DIV_EXPR
1730 || code == CEIL_DIV_EXPR
1731 || code == EXACT_DIV_EXPR
1732 || code == ROUND_DIV_EXPR
1733 || code == RSHIFT_EXPR)
1734 && (is_overflow_infinity (val1)
1735 || is_overflow_infinity (val2)))
1738 /* Notice that we only need to handle the restricted set of
1739 operations handled by extract_range_from_binary_expr.
1740 Among them, only multiplication, addition and subtraction
1741 can yield overflow without overflown operands because we
1742 are working with integral types only... except in the
1743 case VAL1 = -INF and VAL2 = -1 which overflows to +INF
1744 for division too. */
1746 /* For multiplication, the sign of the overflow is given
1747 by the comparison of the signs of the operands. */
1748 if ((code == MULT_EXPR && sgn1 == sgn2)
1749 /* For addition, the operands must be of the same sign
1750 to yield an overflow. Its sign is therefore that
1751 of one of the operands, for example the first. For
1752 infinite operands X + -INF is negative, not positive. */
1753 || (code == PLUS_EXPR
1755 ? !is_negative_overflow_infinity (val2)
1756 : is_positive_overflow_infinity (val2)))
1757 /* For subtraction, non-infinite operands must be of
1758 different signs to yield an overflow. Its sign is
1759 therefore that of the first operand or the opposite of
1760 that of the second operand. A first operand of 0 counts
1761 as positive here, for the corner case 0 - (-INF), which
1762 overflows, but must yield +INF. For infinite operands 0
1763 - INF is negative, not positive. */
1764 || (code == MINUS_EXPR
1766 ? !is_positive_overflow_infinity (val2)
1767 : is_negative_overflow_infinity (val2)))
1768 /* We only get in here with positive shift count, so the
1769 overflow direction is the same as the sign of val1.
1770 Actually rshift does not overflow at all, but we only
1771 handle the case of shifting overflowed -INF and +INF. */
1772 || (code == RSHIFT_EXPR
1774 /* For division, the only case is -INF / -1 = +INF. */
1775 || code == TRUNC_DIV_EXPR
1776 || code == FLOOR_DIV_EXPR
1777 || code == CEIL_DIV_EXPR
1778 || code == EXACT_DIV_EXPR
1779 || code == ROUND_DIV_EXPR)
1780 return (needs_overflow_infinity (TREE_TYPE (res))
1781 ? positive_overflow_infinity (TREE_TYPE (res))
1782 : TYPE_MAX_VALUE (TREE_TYPE (res)));
1784 return (needs_overflow_infinity (TREE_TYPE (res))
1785 ? negative_overflow_infinity (TREE_TYPE (res))
1786 : TYPE_MIN_VALUE (TREE_TYPE (res)));
1793 /* Extract range information from a binary expression EXPR based on
1794 the ranges of each of its operands and the expression code. */
1797 extract_range_from_binary_expr (value_range_t *vr,
1798 enum tree_code code,
1799 tree expr_type, tree op0, tree op1)
1801 enum value_range_type type;
1804 value_range_t vr0 = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
1805 value_range_t vr1 = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
1807 /* Not all binary expressions can be applied to ranges in a
1808 meaningful way. Handle only arithmetic operations. */
1809 if (code != PLUS_EXPR
1810 && code != MINUS_EXPR
1811 && code != POINTER_PLUS_EXPR
1812 && code != MULT_EXPR
1813 && code != TRUNC_DIV_EXPR
1814 && code != FLOOR_DIV_EXPR
1815 && code != CEIL_DIV_EXPR
1816 && code != EXACT_DIV_EXPR
1817 && code != ROUND_DIV_EXPR
1818 && code != RSHIFT_EXPR
1821 && code != BIT_AND_EXPR
1822 && code != TRUTH_ANDIF_EXPR
1823 && code != TRUTH_ORIF_EXPR
1824 && code != TRUTH_AND_EXPR
1825 && code != TRUTH_OR_EXPR)
1827 set_value_range_to_varying (vr);
1831 /* Get value ranges for each operand. For constant operands, create
1832 a new value range with the operand to simplify processing. */
1833 if (TREE_CODE (op0) == SSA_NAME)
1834 vr0 = *(get_value_range (op0));
1835 else if (is_gimple_min_invariant (op0))
1836 set_value_range_to_value (&vr0, op0, NULL);
1838 set_value_range_to_varying (&vr0);
1840 if (TREE_CODE (op1) == SSA_NAME)
1841 vr1 = *(get_value_range (op1));
1842 else if (is_gimple_min_invariant (op1))
1843 set_value_range_to_value (&vr1, op1, NULL);
1845 set_value_range_to_varying (&vr1);
1847 /* If either range is UNDEFINED, so is the result. */
1848 if (vr0.type == VR_UNDEFINED || vr1.type == VR_UNDEFINED)
1850 set_value_range_to_undefined (vr);
1854 /* The type of the resulting value range defaults to VR0.TYPE. */
1857 /* Refuse to operate on VARYING ranges, ranges of different kinds
1858 and symbolic ranges. As an exception, we allow BIT_AND_EXPR
1859 because we may be able to derive a useful range even if one of
1860 the operands is VR_VARYING or symbolic range. TODO, we may be
1861 able to derive anti-ranges in some cases. */
1862 if (code != BIT_AND_EXPR
1863 && code != TRUTH_AND_EXPR
1864 && code != TRUTH_OR_EXPR
1865 && (vr0.type == VR_VARYING
1866 || vr1.type == VR_VARYING
1867 || vr0.type != vr1.type
1868 || symbolic_range_p (&vr0)
1869 || symbolic_range_p (&vr1)))
1871 set_value_range_to_varying (vr);
1875 /* Now evaluate the expression to determine the new range. */
1876 if (POINTER_TYPE_P (expr_type)
1877 || POINTER_TYPE_P (TREE_TYPE (op0))
1878 || POINTER_TYPE_P (TREE_TYPE (op1)))
1880 if (code == MIN_EXPR || code == MAX_EXPR)
1882 /* For MIN/MAX expressions with pointers, we only care about
1883 nullness, if both are non null, then the result is nonnull.
1884 If both are null, then the result is null. Otherwise they
1886 if (range_is_nonnull (&vr0) && range_is_nonnull (&vr1))
1887 set_value_range_to_nonnull (vr, expr_type);
1888 else if (range_is_null (&vr0) && range_is_null (&vr1))
1889 set_value_range_to_null (vr, expr_type);
1891 set_value_range_to_varying (vr);
1895 gcc_assert (code == POINTER_PLUS_EXPR);
1896 /* For pointer types, we are really only interested in asserting
1897 whether the expression evaluates to non-NULL. */
1898 if (range_is_nonnull (&vr0) || range_is_nonnull (&vr1))
1899 set_value_range_to_nonnull (vr, expr_type);
1900 else if (range_is_null (&vr0) && range_is_null (&vr1))
1901 set_value_range_to_null (vr, expr_type);
1903 set_value_range_to_varying (vr);
1908 /* For integer ranges, apply the operation to each end of the
1909 range and see what we end up with. */
1910 if (code == TRUTH_ANDIF_EXPR
1911 || code == TRUTH_ORIF_EXPR
1912 || code == TRUTH_AND_EXPR
1913 || code == TRUTH_OR_EXPR)
1915 /* If one of the operands is zero, we know that the whole
1916 expression evaluates zero. */
1917 if (code == TRUTH_AND_EXPR
1918 && ((vr0.type == VR_RANGE
1919 && integer_zerop (vr0.min)
1920 && integer_zerop (vr0.max))
1921 || (vr1.type == VR_RANGE
1922 && integer_zerop (vr1.min)
1923 && integer_zerop (vr1.max))))
1926 min = max = build_int_cst (expr_type, 0);
1928 /* If one of the operands is one, we know that the whole
1929 expression evaluates one. */
1930 else if (code == TRUTH_OR_EXPR
1931 && ((vr0.type == VR_RANGE
1932 && integer_onep (vr0.min)
1933 && integer_onep (vr0.max))
1934 || (vr1.type == VR_RANGE
1935 && integer_onep (vr1.min)
1936 && integer_onep (vr1.max))))
1939 min = max = build_int_cst (expr_type, 1);
1941 else if (vr0.type != VR_VARYING
1942 && vr1.type != VR_VARYING
1943 && vr0.type == vr1.type
1944 && !symbolic_range_p (&vr0)
1945 && !overflow_infinity_range_p (&vr0)
1946 && !symbolic_range_p (&vr1)
1947 && !overflow_infinity_range_p (&vr1))
1949 /* Boolean expressions cannot be folded with int_const_binop. */
1950 min = fold_binary (code, expr_type, vr0.min, vr1.min);
1951 max = fold_binary (code, expr_type, vr0.max, vr1.max);
1955 /* The result of a TRUTH_*_EXPR is always true or false. */
1956 set_value_range_to_truthvalue (vr, expr_type);
1960 else if (code == PLUS_EXPR
1962 || code == MAX_EXPR)
1964 /* If we have a PLUS_EXPR with two VR_ANTI_RANGEs, drop to
1965 VR_VARYING. It would take more effort to compute a precise
1966 range for such a case. For example, if we have op0 == 1 and
1967 op1 == -1 with their ranges both being ~[0,0], we would have
1968 op0 + op1 == 0, so we cannot claim that the sum is in ~[0,0].
1969 Note that we are guaranteed to have vr0.type == vr1.type at
1971 if (code == PLUS_EXPR && vr0.type == VR_ANTI_RANGE)
1973 set_value_range_to_varying (vr);
1977 /* For operations that make the resulting range directly
1978 proportional to the original ranges, apply the operation to
1979 the same end of each range. */
1980 min = vrp_int_const_binop (code, vr0.min, vr1.min);
1981 max = vrp_int_const_binop (code, vr0.max, vr1.max);
1983 else if (code == MULT_EXPR
1984 || code == TRUNC_DIV_EXPR
1985 || code == FLOOR_DIV_EXPR
1986 || code == CEIL_DIV_EXPR
1987 || code == EXACT_DIV_EXPR
1988 || code == ROUND_DIV_EXPR
1989 || code == RSHIFT_EXPR)
1995 /* If we have an unsigned MULT_EXPR with two VR_ANTI_RANGEs,
1996 drop to VR_VARYING. It would take more effort to compute a
1997 precise range for such a case. For example, if we have
1998 op0 == 65536 and op1 == 65536 with their ranges both being
1999 ~[0,0] on a 32-bit machine, we would have op0 * op1 == 0, so
2000 we cannot claim that the product is in ~[0,0]. Note that we
2001 are guaranteed to have vr0.type == vr1.type at this
2003 if (code == MULT_EXPR
2004 && vr0.type == VR_ANTI_RANGE
2005 && !TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (op0)))
2007 set_value_range_to_varying (vr);
2011 /* If we have a RSHIFT_EXPR with any shift values outside [0..prec-1],
2012 then drop to VR_VARYING. Outside of this range we get undefined
2013 behavior from the shift operation. We cannot even trust
2014 SHIFT_COUNT_TRUNCATED at this stage, because that applies to rtl
2015 shifts, and the operation at the tree level may be widened. */
2016 if (code == RSHIFT_EXPR)
2018 if (vr1.type == VR_ANTI_RANGE
2019 || !vrp_expr_computes_nonnegative (op1, &sop)
2021 (build_int_cst (TREE_TYPE (vr1.max),
2022 TYPE_PRECISION (expr_type) - 1),
2025 set_value_range_to_varying (vr);
2030 /* Multiplications and divisions are a bit tricky to handle,
2031 depending on the mix of signs we have in the two ranges, we
2032 need to operate on different values to get the minimum and
2033 maximum values for the new range. One approach is to figure
2034 out all the variations of range combinations and do the
2037 However, this involves several calls to compare_values and it
2038 is pretty convoluted. It's simpler to do the 4 operations
2039 (MIN0 OP MIN1, MIN0 OP MAX1, MAX0 OP MIN1 and MAX0 OP MAX0 OP
2040 MAX1) and then figure the smallest and largest values to form
2043 /* Divisions by zero result in a VARYING value. */
2044 else if (code != MULT_EXPR
2045 && (vr0.type == VR_ANTI_RANGE || range_includes_zero_p (&vr1)))
2047 set_value_range_to_varying (vr);
2051 /* Compute the 4 cross operations. */
2053 val[0] = vrp_int_const_binop (code, vr0.min, vr1.min);
2054 if (val[0] == NULL_TREE)
2057 if (vr1.max == vr1.min)
2061 val[1] = vrp_int_const_binop (code, vr0.min, vr1.max);
2062 if (val[1] == NULL_TREE)
2066 if (vr0.max == vr0.min)
2070 val[2] = vrp_int_const_binop (code, vr0.max, vr1.min);
2071 if (val[2] == NULL_TREE)
2075 if (vr0.min == vr0.max || vr1.min == vr1.max)
2079 val[3] = vrp_int_const_binop (code, vr0.max, vr1.max);
2080 if (val[3] == NULL_TREE)
2086 set_value_range_to_varying (vr);
2090 /* Set MIN to the minimum of VAL[i] and MAX to the maximum
2094 for (i = 1; i < 4; i++)
2096 if (!is_gimple_min_invariant (min)
2097 || (TREE_OVERFLOW (min) && !is_overflow_infinity (min))
2098 || !is_gimple_min_invariant (max)
2099 || (TREE_OVERFLOW (max) && !is_overflow_infinity (max)))
2104 if (!is_gimple_min_invariant (val[i])
2105 || (TREE_OVERFLOW (val[i])
2106 && !is_overflow_infinity (val[i])))
2108 /* If we found an overflowed value, set MIN and MAX
2109 to it so that we set the resulting range to
2115 if (compare_values (val[i], min) == -1)
2118 if (compare_values (val[i], max) == 1)
2123 else if (code == MINUS_EXPR)
2125 /* If we have a MINUS_EXPR with two VR_ANTI_RANGEs, drop to
2126 VR_VARYING. It would take more effort to compute a precise
2127 range for such a case. For example, if we have op0 == 1 and
2128 op1 == 1 with their ranges both being ~[0,0], we would have
2129 op0 - op1 == 0, so we cannot claim that the difference is in
2130 ~[0,0]. Note that we are guaranteed to have
2131 vr0.type == vr1.type at this point. */
2132 if (vr0.type == VR_ANTI_RANGE)
2134 set_value_range_to_varying (vr);
2138 /* For MINUS_EXPR, apply the operation to the opposite ends of
2140 min = vrp_int_const_binop (code, vr0.min, vr1.max);
2141 max = vrp_int_const_binop (code, vr0.max, vr1.min);
2143 else if (code == BIT_AND_EXPR)
2145 if (vr0.type == VR_RANGE
2146 && vr0.min == vr0.max
2147 && TREE_CODE (vr0.max) == INTEGER_CST
2148 && !TREE_OVERFLOW (vr0.max)
2149 && tree_int_cst_sgn (vr0.max) >= 0)
2151 min = build_int_cst (expr_type, 0);
2154 else if (vr1.type == VR_RANGE
2155 && vr1.min == vr1.max
2156 && TREE_CODE (vr1.max) == INTEGER_CST
2157 && !TREE_OVERFLOW (vr1.max)
2158 && tree_int_cst_sgn (vr1.max) >= 0)
2161 min = build_int_cst (expr_type, 0);
2166 set_value_range_to_varying (vr);
2173 /* If either MIN or MAX overflowed, then set the resulting range to
2174 VARYING. But we do accept an overflow infinity
2176 if (min == NULL_TREE
2177 || !is_gimple_min_invariant (min)
2178 || (TREE_OVERFLOW (min) && !is_overflow_infinity (min))
2180 || !is_gimple_min_invariant (max)
2181 || (TREE_OVERFLOW (max) && !is_overflow_infinity (max)))
2183 set_value_range_to_varying (vr);
2189 2) [-INF, +-INF(OVF)]
2190 3) [+-INF(OVF), +INF]
2191 4) [+-INF(OVF), +-INF(OVF)]
2192 We learn nothing when we have INF and INF(OVF) on both sides.
2193 Note that we do accept [-INF, -INF] and [+INF, +INF] without
2195 if ((vrp_val_is_min (min) || is_overflow_infinity (min))
2196 && (vrp_val_is_max (max) || is_overflow_infinity (max)))
2198 set_value_range_to_varying (vr);
2202 cmp = compare_values (min, max);
2203 if (cmp == -2 || cmp == 1)
2205 /* If the new range has its limits swapped around (MIN > MAX),
2206 then the operation caused one of them to wrap around, mark
2207 the new range VARYING. */
2208 set_value_range_to_varying (vr);
2211 set_value_range (vr, type, min, max, NULL);
2215 /* Extract range information from a unary expression EXPR based on
2216 the range of its operand and the expression code. */
2219 extract_range_from_unary_expr (value_range_t *vr, enum tree_code code,
2220 tree type, tree op0)
2224 value_range_t vr0 = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
2226 /* Refuse to operate on certain unary expressions for which we
2227 cannot easily determine a resulting range. */
2228 if (code == FIX_TRUNC_EXPR
2229 || code == FLOAT_EXPR
2230 || code == BIT_NOT_EXPR
2231 || code == NON_LVALUE_EXPR
2232 || code == CONJ_EXPR)
2234 set_value_range_to_varying (vr);
2238 /* Get value ranges for the operand. For constant operands, create
2239 a new value range with the operand to simplify processing. */
2240 if (TREE_CODE (op0) == SSA_NAME)
2241 vr0 = *(get_value_range (op0));
2242 else if (is_gimple_min_invariant (op0))
2243 set_value_range_to_value (&vr0, op0, NULL);
2245 set_value_range_to_varying (&vr0);
2247 /* If VR0 is UNDEFINED, so is the result. */
2248 if (vr0.type == VR_UNDEFINED)
2250 set_value_range_to_undefined (vr);
2254 /* Refuse to operate on symbolic ranges, or if neither operand is
2255 a pointer or integral type. */
2256 if ((!INTEGRAL_TYPE_P (TREE_TYPE (op0))
2257 && !POINTER_TYPE_P (TREE_TYPE (op0)))
2258 || (vr0.type != VR_VARYING
2259 && symbolic_range_p (&vr0)))
2261 set_value_range_to_varying (vr);
2265 /* If the expression involves pointers, we are only interested in
2266 determining if it evaluates to NULL [0, 0] or non-NULL (~[0, 0]). */
2267 if (POINTER_TYPE_P (type) || POINTER_TYPE_P (TREE_TYPE (op0)))
2272 if (range_is_nonnull (&vr0)
2273 || (tree_unary_nonzero_warnv_p (code, type, op0, &sop)
2275 set_value_range_to_nonnull (vr, type);
2276 else if (range_is_null (&vr0))
2277 set_value_range_to_null (vr, type);
2279 set_value_range_to_varying (vr);
2284 /* Handle unary expressions on integer ranges. */
2285 if (code == NOP_EXPR || code == CONVERT_EXPR)
2287 tree inner_type = TREE_TYPE (op0);
2288 tree outer_type = type;
2290 /* If VR0 represents a simple range, then try to convert
2291 the min and max values for the range to the same type
2292 as OUTER_TYPE. If the results compare equal to VR0's
2293 min and max values and the new min is still less than
2294 or equal to the new max, then we can safely use the newly
2295 computed range for EXPR. This allows us to compute
2296 accurate ranges through many casts. */
2297 if ((vr0.type == VR_RANGE
2298 && !overflow_infinity_range_p (&vr0))
2299 || (vr0.type == VR_VARYING
2300 && TYPE_PRECISION (outer_type) > TYPE_PRECISION (inner_type)))
2302 tree new_min, new_max, orig_min, orig_max;
2304 /* Convert the input operand min/max to OUTER_TYPE. If
2305 the input has no range information, then use the min/max
2306 for the input's type. */
2307 if (vr0.type == VR_RANGE)
2314 orig_min = TYPE_MIN_VALUE (inner_type);
2315 orig_max = TYPE_MAX_VALUE (inner_type);
2318 new_min = fold_convert (outer_type, orig_min);
2319 new_max = fold_convert (outer_type, orig_max);
2321 /* Verify the new min/max values are gimple values and
2322 that they compare equal to the original input's
2324 if (is_gimple_val (new_min)
2325 && is_gimple_val (new_max)
2326 && tree_int_cst_equal (new_min, orig_min)
2327 && tree_int_cst_equal (new_max, orig_max)
2328 && (!is_overflow_infinity (new_min)
2329 || !is_overflow_infinity (new_max))
2330 && (cmp = compare_values (new_min, new_max)) <= 0
2333 set_value_range (vr, VR_RANGE, new_min, new_max, vr->equiv);
2338 /* When converting types of different sizes, set the result to
2339 VARYING. Things like sign extensions and precision loss may
2340 change the range. For instance, if x_3 is of type 'long long
2341 int' and 'y_5 = (unsigned short) x_3', if x_3 is ~[0, 0], it
2342 is impossible to know at compile time whether y_5 will be
2344 if (TYPE_SIZE (inner_type) != TYPE_SIZE (outer_type)
2345 || TYPE_PRECISION (inner_type) != TYPE_PRECISION (outer_type))
2347 set_value_range_to_varying (vr);
2352 /* Conversion of a VR_VARYING value to a wider type can result
2353 in a usable range. So wait until after we've handled conversions
2354 before dropping the result to VR_VARYING if we had a source
2355 operand that is VR_VARYING. */
2356 if (vr0.type == VR_VARYING)
2358 set_value_range_to_varying (vr);
2362 /* Apply the operation to each end of the range and see what we end
2364 if (code == NEGATE_EXPR
2365 && !TYPE_UNSIGNED (type))
2367 /* NEGATE_EXPR flips the range around. We need to treat
2368 TYPE_MIN_VALUE specially. */
2369 if (is_positive_overflow_infinity (vr0.max))
2370 min = negative_overflow_infinity (type);
2371 else if (is_negative_overflow_infinity (vr0.max))
2372 min = positive_overflow_infinity (type);
2373 else if (!vrp_val_is_min (vr0.max))
2374 min = fold_unary_to_constant (code, type, vr0.max);
2375 else if (needs_overflow_infinity (type))
2377 if (supports_overflow_infinity (type)
2378 && !is_overflow_infinity (vr0.min)
2379 && !vrp_val_is_min (vr0.min))
2380 min = positive_overflow_infinity (type);
2383 set_value_range_to_varying (vr);
2388 min = TYPE_MIN_VALUE (type);
2390 if (is_positive_overflow_infinity (vr0.min))
2391 max = negative_overflow_infinity (type);
2392 else if (is_negative_overflow_infinity (vr0.min))
2393 max = positive_overflow_infinity (type);
2394 else if (!vrp_val_is_min (vr0.min))
2395 max = fold_unary_to_constant (code, type, vr0.min);
2396 else if (needs_overflow_infinity (type))
2398 if (supports_overflow_infinity (type))
2399 max = positive_overflow_infinity (type);
2402 set_value_range_to_varying (vr);
2407 max = TYPE_MIN_VALUE (type);
2409 else if (code == NEGATE_EXPR
2410 && TYPE_UNSIGNED (type))
2412 if (!range_includes_zero_p (&vr0))
2414 max = fold_unary_to_constant (code, type, vr0.min);
2415 min = fold_unary_to_constant (code, type, vr0.max);
2419 if (range_is_null (&vr0))
2420 set_value_range_to_null (vr, type);
2422 set_value_range_to_varying (vr);
2426 else if (code == ABS_EXPR
2427 && !TYPE_UNSIGNED (type))
2429 /* -TYPE_MIN_VALUE = TYPE_MIN_VALUE with flag_wrapv so we can't get a
2431 if (!TYPE_OVERFLOW_UNDEFINED (type)
2432 && ((vr0.type == VR_RANGE
2433 && vrp_val_is_min (vr0.min))
2434 || (vr0.type == VR_ANTI_RANGE
2435 && !vrp_val_is_min (vr0.min)
2436 && !range_includes_zero_p (&vr0))))
2438 set_value_range_to_varying (vr);
2442 /* ABS_EXPR may flip the range around, if the original range
2443 included negative values. */
2444 if (is_overflow_infinity (vr0.min))
2445 min = positive_overflow_infinity (type);
2446 else if (!vrp_val_is_min (vr0.min))
2447 min = fold_unary_to_constant (code, type, vr0.min);
2448 else if (!needs_overflow_infinity (type))
2449 min = TYPE_MAX_VALUE (type);
2450 else if (supports_overflow_infinity (type))
2451 min = positive_overflow_infinity (type);
2454 set_value_range_to_varying (vr);
2458 if (is_overflow_infinity (vr0.max))
2459 max = positive_overflow_infinity (type);
2460 else if (!vrp_val_is_min (vr0.max))
2461 max = fold_unary_to_constant (code, type, vr0.max);
2462 else if (!needs_overflow_infinity (type))
2463 max = TYPE_MAX_VALUE (type);
2464 else if (supports_overflow_infinity (type))
2465 max = positive_overflow_infinity (type);
2468 set_value_range_to_varying (vr);
2472 cmp = compare_values (min, max);
2474 /* If a VR_ANTI_RANGEs contains zero, then we have
2475 ~[-INF, min(MIN, MAX)]. */
2476 if (vr0.type == VR_ANTI_RANGE)
2478 if (range_includes_zero_p (&vr0))
2480 /* Take the lower of the two values. */
2484 /* Create ~[-INF, min (abs(MIN), abs(MAX))]
2485 or ~[-INF + 1, min (abs(MIN), abs(MAX))] when
2486 flag_wrapv is set and the original anti-range doesn't include
2487 TYPE_MIN_VALUE, remember -TYPE_MIN_VALUE = TYPE_MIN_VALUE. */
2488 if (TYPE_OVERFLOW_WRAPS (type))
2490 tree type_min_value = TYPE_MIN_VALUE (type);
2492 min = (vr0.min != type_min_value
2493 ? int_const_binop (PLUS_EXPR, type_min_value,
2494 integer_one_node, 0)
2499 if (overflow_infinity_range_p (&vr0))
2500 min = negative_overflow_infinity (type);
2502 min = TYPE_MIN_VALUE (type);
2507 /* All else has failed, so create the range [0, INF], even for
2508 flag_wrapv since TYPE_MIN_VALUE is in the original
2510 vr0.type = VR_RANGE;
2511 min = build_int_cst (type, 0);
2512 if (needs_overflow_infinity (type))
2514 if (supports_overflow_infinity (type))
2515 max = positive_overflow_infinity (type);
2518 set_value_range_to_varying (vr);
2523 max = TYPE_MAX_VALUE (type);
2527 /* If the range contains zero then we know that the minimum value in the
2528 range will be zero. */
2529 else if (range_includes_zero_p (&vr0))
2533 min = build_int_cst (type, 0);
2537 /* If the range was reversed, swap MIN and MAX. */
2548 /* Otherwise, operate on each end of the range. */
2549 min = fold_unary_to_constant (code, type, vr0.min);
2550 max = fold_unary_to_constant (code, type, vr0.max);
2552 if (needs_overflow_infinity (type))
2554 gcc_assert (code != NEGATE_EXPR && code != ABS_EXPR);
2556 /* If both sides have overflowed, we don't know
2558 if ((is_overflow_infinity (vr0.min)
2559 || TREE_OVERFLOW (min))
2560 && (is_overflow_infinity (vr0.max)
2561 || TREE_OVERFLOW (max)))
2563 set_value_range_to_varying (vr);
2567 if (is_overflow_infinity (vr0.min))
2569 else if (TREE_OVERFLOW (min))
2571 if (supports_overflow_infinity (type))
2572 min = (tree_int_cst_sgn (min) >= 0
2573 ? positive_overflow_infinity (TREE_TYPE (min))
2574 : negative_overflow_infinity (TREE_TYPE (min)));
2577 set_value_range_to_varying (vr);
2582 if (is_overflow_infinity (vr0.max))
2584 else if (TREE_OVERFLOW (max))
2586 if (supports_overflow_infinity (type))
2587 max = (tree_int_cst_sgn (max) >= 0
2588 ? positive_overflow_infinity (TREE_TYPE (max))
2589 : negative_overflow_infinity (TREE_TYPE (max)));
2592 set_value_range_to_varying (vr);
2599 cmp = compare_values (min, max);
2600 if (cmp == -2 || cmp == 1)
2602 /* If the new range has its limits swapped around (MIN > MAX),
2603 then the operation caused one of them to wrap around, mark
2604 the new range VARYING. */
2605 set_value_range_to_varying (vr);
2608 set_value_range (vr, vr0.type, min, max, NULL);
2612 /* Extract range information from a conditional expression EXPR based on
2613 the ranges of each of its operands and the expression code. */
2616 extract_range_from_cond_expr (value_range_t *vr, tree expr)
2619 value_range_t vr0 = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
2620 value_range_t vr1 = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
2622 /* Get value ranges for each operand. For constant operands, create
2623 a new value range with the operand to simplify processing. */
2624 op0 = COND_EXPR_THEN (expr);
2625 if (TREE_CODE (op0) == SSA_NAME)
2626 vr0 = *(get_value_range (op0));
2627 else if (is_gimple_min_invariant (op0))
2628 set_value_range_to_value (&vr0, op0, NULL);
2630 set_value_range_to_varying (&vr0);
2632 op1 = COND_EXPR_ELSE (expr);
2633 if (TREE_CODE (op1) == SSA_NAME)
2634 vr1 = *(get_value_range (op1));
2635 else if (is_gimple_min_invariant (op1))
2636 set_value_range_to_value (&vr1, op1, NULL);
2638 set_value_range_to_varying (&vr1);
2640 /* The resulting value range is the union of the operand ranges */
2641 vrp_meet (&vr0, &vr1);
2642 copy_value_range (vr, &vr0);
2646 /* Extract range information from a comparison expression EXPR based
2647 on the range of its operand and the expression code. */
2650 extract_range_from_comparison (value_range_t *vr, enum tree_code code,
2651 tree type, tree op0, tree op1)
2654 tree val = vrp_evaluate_conditional_warnv_with_ops (code,
2659 /* A disadvantage of using a special infinity as an overflow
2660 representation is that we lose the ability to record overflow
2661 when we don't have an infinity. So we have to ignore a result
2662 which relies on overflow. */
2664 if (val && !is_overflow_infinity (val) && !sop)
2666 /* Since this expression was found on the RHS of an assignment,
2667 its type may be different from _Bool. Convert VAL to EXPR's
2669 val = fold_convert (type, val);
2670 if (is_gimple_min_invariant (val))
2671 set_value_range_to_value (vr, val, vr->equiv);
2673 set_value_range (vr, VR_RANGE, val, val, vr->equiv);
2676 /* The result of a comparison is always true or false. */
2677 set_value_range_to_truthvalue (vr, type);
2681 /* Try to compute a useful range out of expression EXPR and store it
2685 extract_range_from_expr (value_range_t *vr, tree expr)
2687 enum tree_code code = TREE_CODE (expr);
2689 if (code == ASSERT_EXPR)
2690 extract_range_from_assert (vr, expr);
2691 else if (code == SSA_NAME)
2692 extract_range_from_ssa_name (vr, expr);
2693 else if (TREE_CODE_CLASS (code) == tcc_binary
2694 || code == TRUTH_ANDIF_EXPR
2695 || code == TRUTH_ORIF_EXPR
2696 || code == TRUTH_AND_EXPR
2697 || code == TRUTH_OR_EXPR
2698 || code == TRUTH_XOR_EXPR)
2699 extract_range_from_binary_expr (vr, TREE_CODE (expr), TREE_TYPE (expr),
2700 TREE_OPERAND (expr, 0),
2701 TREE_OPERAND (expr, 1));
2702 else if (TREE_CODE_CLASS (code) == tcc_unary)
2703 extract_range_from_unary_expr (vr, TREE_CODE (expr), TREE_TYPE (expr),
2704 TREE_OPERAND (expr, 0));
2705 else if (code == COND_EXPR)
2706 extract_range_from_cond_expr (vr, expr);
2707 else if (TREE_CODE_CLASS (code) == tcc_comparison)
2708 extract_range_from_comparison (vr, TREE_CODE (expr), TREE_TYPE (expr),
2709 TREE_OPERAND (expr, 0),
2710 TREE_OPERAND (expr, 1));
2711 else if (is_gimple_min_invariant (expr))
2712 set_value_range_to_value (vr, expr, NULL);
2714 set_value_range_to_varying (vr);
2716 /* If we got a varying range from the tests above, try a final
2717 time to derive a nonnegative or nonzero range. This time
2718 relying primarily on generic routines in fold in conjunction
2720 if (vr->type == VR_VARYING)
2724 if (INTEGRAL_TYPE_P (TREE_TYPE (expr))
2725 && vrp_expr_computes_nonnegative (expr, &sop))
2726 set_value_range_to_nonnegative (vr, TREE_TYPE (expr),
2727 sop || is_overflow_infinity (expr));
2728 else if (vrp_expr_computes_nonzero (expr, &sop)
2730 set_value_range_to_nonnull (vr, TREE_TYPE (expr));
2734 /* Given a range VR, a LOOP and a variable VAR, determine whether it
2735 would be profitable to adjust VR using scalar evolution information
2736 for VAR. If so, update VR with the new limits. */
2739 adjust_range_with_scev (value_range_t *vr, struct loop *loop, tree stmt,
2742 tree init, step, chrec, tmin, tmax, min, max, type;
2743 enum ev_direction dir;
2745 /* TODO. Don't adjust anti-ranges. An anti-range may provide
2746 better opportunities than a regular range, but I'm not sure. */
2747 if (vr->type == VR_ANTI_RANGE)
2750 /* Ensure that there are not values in the scev cache based on assumptions
2751 on ranges of ssa names that were changed
2752 (in set_value_range/set_value_range_to_varying). Preserve cached numbers
2753 of iterations, that were computed before the start of VRP (we do not
2754 recompute these each time to save the compile time). */
2755 scev_reset_except_niters ();
2757 chrec = instantiate_parameters (loop, analyze_scalar_evolution (loop, var));
2759 /* Like in PR19590, scev can return a constant function. */
2760 if (is_gimple_min_invariant (chrec))
2762 set_value_range_to_value (vr, chrec, vr->equiv);
2766 if (TREE_CODE (chrec) != POLYNOMIAL_CHREC)
2769 init = initial_condition_in_loop_num (chrec, loop->num);
2770 step = evolution_part_in_loop_num (chrec, loop->num);
2772 /* If STEP is symbolic, we can't know whether INIT will be the
2773 minimum or maximum value in the range. Also, unless INIT is
2774 a simple expression, compare_values and possibly other functions
2775 in tree-vrp won't be able to handle it. */
2776 if (step == NULL_TREE
2777 || !is_gimple_min_invariant (step)
2778 || !valid_value_p (init))
2781 dir = scev_direction (chrec);
2782 if (/* Do not adjust ranges if we do not know whether the iv increases
2783 or decreases, ... */
2784 dir == EV_DIR_UNKNOWN
2785 /* ... or if it may wrap. */
2786 || scev_probably_wraps_p (init, step, stmt, get_chrec_loop (chrec),
2790 /* We use TYPE_MIN_VALUE and TYPE_MAX_VALUE here instead of
2791 negative_overflow_infinity and positive_overflow_infinity,
2792 because we have concluded that the loop probably does not
2795 type = TREE_TYPE (var);
2796 if (POINTER_TYPE_P (type) || !TYPE_MIN_VALUE (type))
2797 tmin = lower_bound_in_type (type, type);
2799 tmin = TYPE_MIN_VALUE (type);
2800 if (POINTER_TYPE_P (type) || !TYPE_MAX_VALUE (type))
2801 tmax = upper_bound_in_type (type, type);
2803 tmax = TYPE_MAX_VALUE (type);
2805 if (vr->type == VR_VARYING || vr->type == VR_UNDEFINED)
2810 /* For VARYING or UNDEFINED ranges, just about anything we get
2811 from scalar evolutions should be better. */
2813 if (dir == EV_DIR_DECREASES)
2818 /* If we would create an invalid range, then just assume we
2819 know absolutely nothing. This may be over-conservative,
2820 but it's clearly safe, and should happen only in unreachable
2821 parts of code, or for invalid programs. */
2822 if (compare_values (min, max) == 1)
2825 set_value_range (vr, VR_RANGE, min, max, vr->equiv);
2827 else if (vr->type == VR_RANGE)
2832 if (dir == EV_DIR_DECREASES)
2834 /* INIT is the maximum value. If INIT is lower than VR->MAX
2835 but no smaller than VR->MIN, set VR->MAX to INIT. */
2836 if (compare_values (init, max) == -1)
2840 /* If we just created an invalid range with the minimum
2841 greater than the maximum, we fail conservatively.
2842 This should happen only in unreachable
2843 parts of code, or for invalid programs. */
2844 if (compare_values (min, max) == 1)
2848 /* According to the loop information, the variable does not
2849 overflow. If we think it does, probably because of an
2850 overflow due to arithmetic on a different INF value,
2852 if (is_negative_overflow_infinity (min))
2857 /* If INIT is bigger than VR->MIN, set VR->MIN to INIT. */
2858 if (compare_values (init, min) == 1)
2862 /* Again, avoid creating invalid range by failing. */
2863 if (compare_values (min, max) == 1)
2867 if (is_positive_overflow_infinity (max))
2871 set_value_range (vr, VR_RANGE, min, max, vr->equiv);
2875 /* Return true if VAR may overflow at STMT. This checks any available
2876 loop information to see if we can determine that VAR does not
2880 vrp_var_may_overflow (tree var, tree stmt)
2883 tree chrec, init, step;
2885 if (current_loops == NULL)
2888 l = loop_containing_stmt (stmt);
2892 chrec = instantiate_parameters (l, analyze_scalar_evolution (l, var));
2893 if (TREE_CODE (chrec) != POLYNOMIAL_CHREC)
2896 init = initial_condition_in_loop_num (chrec, l->num);
2897 step = evolution_part_in_loop_num (chrec, l->num);
2899 if (step == NULL_TREE
2900 || !is_gimple_min_invariant (step)
2901 || !valid_value_p (init))
2904 /* If we get here, we know something useful about VAR based on the
2905 loop information. If it wraps, it may overflow. */
2907 if (scev_probably_wraps_p (init, step, stmt, get_chrec_loop (chrec),
2911 if (dump_file && (dump_flags & TDF_DETAILS) != 0)
2913 print_generic_expr (dump_file, var, 0);
2914 fprintf (dump_file, ": loop information indicates does not overflow\n");
2921 /* Given two numeric value ranges VR0, VR1 and a comparison code COMP:
2923 - Return BOOLEAN_TRUE_NODE if VR0 COMP VR1 always returns true for
2924 all the values in the ranges.
2926 - Return BOOLEAN_FALSE_NODE if the comparison always returns false.
2928 - Return NULL_TREE if it is not always possible to determine the
2929 value of the comparison.
2931 Also set *STRICT_OVERFLOW_P to indicate whether a range with an
2932 overflow infinity was used in the test. */
2936 compare_ranges (enum tree_code comp, value_range_t *vr0, value_range_t *vr1,
2937 bool *strict_overflow_p)
2939 /* VARYING or UNDEFINED ranges cannot be compared. */
2940 if (vr0->type == VR_VARYING
2941 || vr0->type == VR_UNDEFINED
2942 || vr1->type == VR_VARYING
2943 || vr1->type == VR_UNDEFINED)
2946 /* Anti-ranges need to be handled separately. */
2947 if (vr0->type == VR_ANTI_RANGE || vr1->type == VR_ANTI_RANGE)
2949 /* If both are anti-ranges, then we cannot compute any
2951 if (vr0->type == VR_ANTI_RANGE && vr1->type == VR_ANTI_RANGE)
2954 /* These comparisons are never statically computable. */
2961 /* Equality can be computed only between a range and an
2962 anti-range. ~[VAL1, VAL2] == [VAL1, VAL2] is always false. */
2963 if (vr0->type == VR_RANGE)
2965 /* To simplify processing, make VR0 the anti-range. */
2966 value_range_t *tmp = vr0;
2971 gcc_assert (comp == NE_EXPR || comp == EQ_EXPR);
2973 if (compare_values_warnv (vr0->min, vr1->min, strict_overflow_p) == 0
2974 && compare_values_warnv (vr0->max, vr1->max, strict_overflow_p) == 0)
2975 return (comp == NE_EXPR) ? boolean_true_node : boolean_false_node;
2980 if (!usable_range_p (vr0, strict_overflow_p)
2981 || !usable_range_p (vr1, strict_overflow_p))
2984 /* Simplify processing. If COMP is GT_EXPR or GE_EXPR, switch the
2985 operands around and change the comparison code. */
2986 if (comp == GT_EXPR || comp == GE_EXPR)
2989 comp = (comp == GT_EXPR) ? LT_EXPR : LE_EXPR;
2995 if (comp == EQ_EXPR)
2997 /* Equality may only be computed if both ranges represent
2998 exactly one value. */
2999 if (compare_values_warnv (vr0->min, vr0->max, strict_overflow_p) == 0
3000 && compare_values_warnv (vr1->min, vr1->max, strict_overflow_p) == 0)
3002 int cmp_min = compare_values_warnv (vr0->min, vr1->min,
3004 int cmp_max = compare_values_warnv (vr0->max, vr1->max,
3006 if (cmp_min == 0 && cmp_max == 0)
3007 return boolean_true_node;
3008 else if (cmp_min != -2 && cmp_max != -2)
3009 return boolean_false_node;
3011 /* If [V0_MIN, V1_MAX] < [V1_MIN, V1_MAX] then V0 != V1. */
3012 else if (compare_values_warnv (vr0->min, vr1->max,
3013 strict_overflow_p) == 1
3014 || compare_values_warnv (vr1->min, vr0->max,
3015 strict_overflow_p) == 1)
3016 return boolean_false_node;
3020 else if (comp == NE_EXPR)
3024 /* If VR0 is completely to the left or completely to the right
3025 of VR1, they are always different. Notice that we need to
3026 make sure that both comparisons yield similar results to
3027 avoid comparing values that cannot be compared at
3029 cmp1 = compare_values_warnv (vr0->max, vr1->min, strict_overflow_p);
3030 cmp2 = compare_values_warnv (vr0->min, vr1->max, strict_overflow_p);
3031 if ((cmp1 == -1 && cmp2 == -1) || (cmp1 == 1 && cmp2 == 1))
3032 return boolean_true_node;
3034 /* If VR0 and VR1 represent a single value and are identical,
3036 else if (compare_values_warnv (vr0->min, vr0->max,
3037 strict_overflow_p) == 0
3038 && compare_values_warnv (vr1->min, vr1->max,
3039 strict_overflow_p) == 0
3040 && compare_values_warnv (vr0->min, vr1->min,
3041 strict_overflow_p) == 0
3042 && compare_values_warnv (vr0->max, vr1->max,
3043 strict_overflow_p) == 0)
3044 return boolean_false_node;
3046 /* Otherwise, they may or may not be different. */
3050 else if (comp == LT_EXPR || comp == LE_EXPR)
3054 /* If VR0 is to the left of VR1, return true. */
3055 tst = compare_values_warnv (vr0->max, vr1->min, strict_overflow_p);
3056 if ((comp == LT_EXPR && tst == -1)
3057 || (comp == LE_EXPR && (tst == -1 || tst == 0)))
3059 if (overflow_infinity_range_p (vr0)
3060 || overflow_infinity_range_p (vr1))
3061 *strict_overflow_p = true;
3062 return boolean_true_node;
3065 /* If VR0 is to the right of VR1, return false. */
3066 tst = compare_values_warnv (vr0->min, vr1->max, strict_overflow_p);
3067 if ((comp == LT_EXPR && (tst == 0 || tst == 1))
3068 || (comp == LE_EXPR && tst == 1))
3070 if (overflow_infinity_range_p (vr0)
3071 || overflow_infinity_range_p (vr1))
3072 *strict_overflow_p = true;
3073 return boolean_false_node;
3076 /* Otherwise, we don't know. */
3084 /* Given a value range VR, a value VAL and a comparison code COMP, return
3085 BOOLEAN_TRUE_NODE if VR COMP VAL always returns true for all the
3086 values in VR. Return BOOLEAN_FALSE_NODE if the comparison
3087 always returns false. Return NULL_TREE if it is not always
3088 possible to determine the value of the comparison. Also set
3089 *STRICT_OVERFLOW_P to indicate whether a range with an overflow
3090 infinity was used in the test. */
3093 compare_range_with_value (enum tree_code comp, value_range_t *vr, tree val,
3094 bool *strict_overflow_p)
3096 if (vr->type == VR_VARYING || vr->type == VR_UNDEFINED)
3099 /* Anti-ranges need to be handled separately. */
3100 if (vr->type == VR_ANTI_RANGE)
3102 /* For anti-ranges, the only predicates that we can compute at
3103 compile time are equality and inequality. */
3110 /* ~[VAL_1, VAL_2] OP VAL is known if VAL_1 <= VAL <= VAL_2. */
3111 if (value_inside_range (val, vr) == 1)
3112 return (comp == NE_EXPR) ? boolean_true_node : boolean_false_node;
3117 if (!usable_range_p (vr, strict_overflow_p))
3120 if (comp == EQ_EXPR)
3122 /* EQ_EXPR may only be computed if VR represents exactly
3124 if (compare_values_warnv (vr->min, vr->max, strict_overflow_p) == 0)
3126 int cmp = compare_values_warnv (vr->min, val, strict_overflow_p);
3128 return boolean_true_node;
3129 else if (cmp == -1 || cmp == 1 || cmp == 2)
3130 return boolean_false_node;
3132 else if (compare_values_warnv (val, vr->min, strict_overflow_p) == -1
3133 || compare_values_warnv (vr->max, val, strict_overflow_p) == -1)
3134 return boolean_false_node;
3138 else if (comp == NE_EXPR)
3140 /* If VAL is not inside VR, then they are always different. */
3141 if (compare_values_warnv (vr->max, val, strict_overflow_p) == -1
3142 || compare_values_warnv (vr->min, val, strict_overflow_p) == 1)
3143 return boolean_true_node;
3145 /* If VR represents exactly one value equal to VAL, then return
3147 if (compare_values_warnv (vr->min, vr->max, strict_overflow_p) == 0
3148 && compare_values_warnv (vr->min, val, strict_overflow_p) == 0)
3149 return boolean_false_node;
3151 /* Otherwise, they may or may not be different. */
3154 else if (comp == LT_EXPR || comp == LE_EXPR)
3158 /* If VR is to the left of VAL, return true. */
3159 tst = compare_values_warnv (vr->max, val, strict_overflow_p);
3160 if ((comp == LT_EXPR && tst == -1)
3161 || (comp == LE_EXPR && (tst == -1 || tst == 0)))
3163 if (overflow_infinity_range_p (vr))
3164 *strict_overflow_p = true;
3165 return boolean_true_node;
3168 /* If VR is to the right of VAL, return false. */
3169 tst = compare_values_warnv (vr->min, val, strict_overflow_p);
3170 if ((comp == LT_EXPR && (tst == 0 || tst == 1))
3171 || (comp == LE_EXPR && tst == 1))
3173 if (overflow_infinity_range_p (vr))
3174 *strict_overflow_p = true;
3175 return boolean_false_node;
3178 /* Otherwise, we don't know. */
3181 else if (comp == GT_EXPR || comp == GE_EXPR)
3185 /* If VR is to the right of VAL, return true. */
3186 tst = compare_values_warnv (vr->min, val, strict_overflow_p);
3187 if ((comp == GT_EXPR && tst == 1)
3188 || (comp == GE_EXPR && (tst == 0 || tst == 1)))
3190 if (overflow_infinity_range_p (vr))
3191 *strict_overflow_p = true;
3192 return boolean_true_node;
3195 /* If VR is to the left of VAL, return false. */
3196 tst = compare_values_warnv (vr->max, val, strict_overflow_p);
3197 if ((comp == GT_EXPR && (tst == -1 || tst == 0))
3198 || (comp == GE_EXPR && tst == -1))
3200 if (overflow_infinity_range_p (vr))
3201 *strict_overflow_p = true;
3202 return boolean_false_node;
3205 /* Otherwise, we don't know. */
3213 /* Debugging dumps. */
3215 void dump_value_range (FILE *, value_range_t *);
3216 void debug_value_range (value_range_t *);
3217 void dump_all_value_ranges (FILE *);
3218 void debug_all_value_ranges (void);
3219 void dump_vr_equiv (FILE *, bitmap);
3220 void debug_vr_equiv (bitmap);
3223 /* Dump value range VR to FILE. */
3226 dump_value_range (FILE *file, value_range_t *vr)
3229 fprintf (file, "[]");
3230 else if (vr->type == VR_UNDEFINED)
3231 fprintf (file, "UNDEFINED");
3232 else if (vr->type == VR_RANGE || vr->type == VR_ANTI_RANGE)
3234 tree type = TREE_TYPE (vr->min);
3236 fprintf (file, "%s[", (vr->type == VR_ANTI_RANGE) ? "~" : "");
3238 if (is_negative_overflow_infinity (vr->min))
3239 fprintf (file, "-INF(OVF)");
3240 else if (INTEGRAL_TYPE_P (type)
3241 && !TYPE_UNSIGNED (type)
3242 && vrp_val_is_min (vr->min))
3243 fprintf (file, "-INF");
3245 print_generic_expr (file, vr->min, 0);
3247 fprintf (file, ", ");
3249 if (is_positive_overflow_infinity (vr->max))
3250 fprintf (file, "+INF(OVF)");
3251 else if (INTEGRAL_TYPE_P (type)
3252 && vrp_val_is_max (vr->max))
3253 fprintf (file, "+INF");
3255 print_generic_expr (file, vr->max, 0);
3257 fprintf (file, "]");
3264 fprintf (file, " EQUIVALENCES: { ");
3266 EXECUTE_IF_SET_IN_BITMAP (vr->equiv, 0, i, bi)
3268 print_generic_expr (file, ssa_name (i), 0);
3269 fprintf (file, " ");
3273 fprintf (file, "} (%u elements)", c);
3276 else if (vr->type == VR_VARYING)
3277 fprintf (file, "VARYING");
3279 fprintf (file, "INVALID RANGE");
3283 /* Dump value range VR to stderr. */
3286 debug_value_range (value_range_t *vr)
3288 dump_value_range (stderr, vr);
3289 fprintf (stderr, "\n");
3293 /* Dump value ranges of all SSA_NAMEs to FILE. */
3296 dump_all_value_ranges (FILE *file)
3300 for (i = 0; i < num_ssa_names; i++)
3304 print_generic_expr (file, ssa_name (i), 0);
3305 fprintf (file, ": ");
3306 dump_value_range (file, vr_value[i]);
3307 fprintf (file, "\n");
3311 fprintf (file, "\n");
3315 /* Dump all value ranges to stderr. */
3318 debug_all_value_ranges (void)
3320 dump_all_value_ranges (stderr);
3324 /* Given a COND_EXPR COND of the form 'V OP W', and an SSA name V,
3325 create a new SSA name N and return the assertion assignment
3326 'V = ASSERT_EXPR <V, V OP W>'. */
3329 build_assert_expr_for (tree cond, tree v)
3333 gcc_assert (TREE_CODE (v) == SSA_NAME);
3334 n = duplicate_ssa_name (v, NULL_TREE);
3336 if (COMPARISON_CLASS_P (cond))
3338 tree a = build2 (ASSERT_EXPR, TREE_TYPE (v), v, cond);
3339 assertion = build_gimple_modify_stmt (n, a);
3341 else if (TREE_CODE (cond) == TRUTH_NOT_EXPR)
3343 /* Given !V, build the assignment N = false. */
3344 tree op0 = TREE_OPERAND (cond, 0);
3345 gcc_assert (op0 == v);
3346 assertion = build_gimple_modify_stmt (n, boolean_false_node);
3348 else if (TREE_CODE (cond) == SSA_NAME)
3350 /* Given V, build the assignment N = true. */
3351 gcc_assert (v == cond);
3352 assertion = build_gimple_modify_stmt (n, boolean_true_node);
3357 SSA_NAME_DEF_STMT (n) = assertion;
3359 /* The new ASSERT_EXPR, creates a new SSA name that replaces the
3360 operand of the ASSERT_EXPR. Register the new name and the old one
3361 in the replacement table so that we can fix the SSA web after
3362 adding all the ASSERT_EXPRs. */
3363 register_new_name_mapping (n, v);
3369 /* Return false if EXPR is a predicate expression involving floating
3373 fp_predicate (const_tree expr)
3375 return (COMPARISON_CLASS_P (expr)
3376 && FLOAT_TYPE_P (TREE_TYPE (TREE_OPERAND (expr, 0))));
3380 /* If the range of values taken by OP can be inferred after STMT executes,
3381 return the comparison code (COMP_CODE_P) and value (VAL_P) that
3382 describes the inferred range. Return true if a range could be
3386 infer_value_range (tree stmt, tree op, enum tree_code *comp_code_p, tree *val_p)
3389 *comp_code_p = ERROR_MARK;
3391 /* Do not attempt to infer anything in names that flow through
3393 if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (op))
3396 /* Similarly, don't infer anything from statements that may throw
3398 if (tree_could_throw_p (stmt))
3401 /* If STMT is the last statement of a basic block with no
3402 successors, there is no point inferring anything about any of its
3403 operands. We would not be able to find a proper insertion point
3404 for the assertion, anyway. */
3405 if (stmt_ends_bb_p (stmt) && EDGE_COUNT (bb_for_stmt (stmt)->succs) == 0)
3408 /* We can only assume that a pointer dereference will yield
3409 non-NULL if -fdelete-null-pointer-checks is enabled. */
3410 if (flag_delete_null_pointer_checks && POINTER_TYPE_P (TREE_TYPE (op)))
3412 unsigned num_uses, num_loads, num_stores;
3414 count_uses_and_derefs (op, stmt, &num_uses, &num_loads, &num_stores);
3415 if (num_loads + num_stores > 0)
3417 *val_p = build_int_cst (TREE_TYPE (op), 0);
3418 *comp_code_p = NE_EXPR;
3427 void dump_asserts_for (FILE *, tree);
3428 void debug_asserts_for (tree);
3429 void dump_all_asserts (FILE *);
3430 void debug_all_asserts (void);
3432 /* Dump all the registered assertions for NAME to FILE. */
3435 dump_asserts_for (FILE *file, tree name)
3439 fprintf (file, "Assertions to be inserted for ");
3440 print_generic_expr (file, name, 0);
3441 fprintf (file, "\n");
3443 loc = asserts_for[SSA_NAME_VERSION (name)];
3446 fprintf (file, "\t");
3447 print_generic_expr (file, bsi_stmt (loc->si), 0);
3448 fprintf (file, "\n\tBB #%d", loc->bb->index);
3451 fprintf (file, "\n\tEDGE %d->%d", loc->e->src->index,
3452 loc->e->dest->index);
3453 dump_edge_info (file, loc->e, 0);
3455 fprintf (file, "\n\tPREDICATE: ");
3456 print_generic_expr (file, name, 0);
3457 fprintf (file, " %s ", tree_code_name[(int)loc->comp_code]);
3458 print_generic_expr (file, loc->val, 0);
3459 fprintf (file, "\n\n");
3463 fprintf (file, "\n");
3467 /* Dump all the registered assertions for NAME to stderr. */
3470 debug_asserts_for (tree name)
3472 dump_asserts_for (stderr, name);
3476 /* Dump all the registered assertions for all the names to FILE. */
3479 dump_all_asserts (FILE *file)
3484 fprintf (file, "\nASSERT_EXPRs to be inserted\n\n");
3485 EXECUTE_IF_SET_IN_BITMAP (need_assert_for, 0, i, bi)
3486 dump_asserts_for (file, ssa_name (i));
3487 fprintf (file, "\n");
3491 /* Dump all the registered assertions for all the names to stderr. */
3494 debug_all_asserts (void)
3496 dump_all_asserts (stderr);
3500 /* If NAME doesn't have an ASSERT_EXPR registered for asserting
3501 'EXPR COMP_CODE VAL' at a location that dominates block BB or
3502 E->DEST, then register this location as a possible insertion point
3503 for ASSERT_EXPR <NAME, EXPR COMP_CODE VAL>.
3505 BB, E and SI provide the exact insertion point for the new
3506 ASSERT_EXPR. If BB is NULL, then the ASSERT_EXPR is to be inserted
3507 on edge E. Otherwise, if E is NULL, the ASSERT_EXPR is inserted on
3508 BB. If SI points to a COND_EXPR or a SWITCH_EXPR statement, then E
3509 must not be NULL. */
3512 register_new_assert_for (tree name, tree expr,
3513 enum tree_code comp_code,
3517 block_stmt_iterator si)
3519 assert_locus_t n, loc, last_loc;
3521 basic_block dest_bb;
3523 #if defined ENABLE_CHECKING
3524 gcc_assert (bb == NULL || e == NULL);
3527 gcc_assert (TREE_CODE (bsi_stmt (si)) != COND_EXPR
3528 && TREE_CODE (bsi_stmt (si)) != SWITCH_EXPR);
3531 /* The new assertion A will be inserted at BB or E. We need to
3532 determine if the new location is dominated by a previously
3533 registered location for A. If we are doing an edge insertion,
3534 assume that A will be inserted at E->DEST. Note that this is not
3537 If E is a critical edge, it will be split. But even if E is
3538 split, the new block will dominate the same set of blocks that
3541 The reverse, however, is not true, blocks dominated by E->DEST
3542 will not be dominated by the new block created to split E. So,
3543 if the insertion location is on a critical edge, we will not use
3544 the new location to move another assertion previously registered
3545 at a block dominated by E->DEST. */
3546 dest_bb = (bb) ? bb : e->dest;
3548 /* If NAME already has an ASSERT_EXPR registered for COMP_CODE and
3549 VAL at a block dominating DEST_BB, then we don't need to insert a new
3550 one. Similarly, if the same assertion already exists at a block
3551 dominated by DEST_BB and the new location is not on a critical
3552 edge, then update the existing location for the assertion (i.e.,
3553 move the assertion up in the dominance tree).
3555 Note, this is implemented as a simple linked list because there
3556 should not be more than a handful of assertions registered per
3557 name. If this becomes a performance problem, a table hashed by
3558 COMP_CODE and VAL could be implemented. */
3559 loc = asserts_for[SSA_NAME_VERSION (name)];
3564 if (loc->comp_code == comp_code
3566 || operand_equal_p (loc->val, val, 0))
3567 && (loc->expr == expr
3568 || operand_equal_p (loc->expr, expr, 0)))
3570 /* If the assertion NAME COMP_CODE VAL has already been
3571 registered at a basic block that dominates DEST_BB, then
3572 we don't need to insert the same assertion again. Note
3573 that we don't check strict dominance here to avoid
3574 replicating the same assertion inside the same basic
3575 block more than once (e.g., when a pointer is
3576 dereferenced several times inside a block).
3578 An exception to this rule are edge insertions. If the
3579 new assertion is to be inserted on edge E, then it will
3580 dominate all the other insertions that we may want to
3581 insert in DEST_BB. So, if we are doing an edge
3582 insertion, don't do this dominance check. */
3584 && dominated_by_p (CDI_DOMINATORS, dest_bb, loc->bb))
3587 /* Otherwise, if E is not a critical edge and DEST_BB
3588 dominates the existing location for the assertion, move
3589 the assertion up in the dominance tree by updating its
3590 location information. */
3591 if ((e == NULL || !EDGE_CRITICAL_P (e))
3592 && dominated_by_p (CDI_DOMINATORS, loc->bb, dest_bb))
3601 /* Update the last node of the list and move to the next one. */
3606 /* If we didn't find an assertion already registered for
3607 NAME COMP_CODE VAL, add a new one at the end of the list of
3608 assertions associated with NAME. */
3609 n = XNEW (struct assert_locus_d);
3613 n->comp_code = comp_code;
3621 asserts_for[SSA_NAME_VERSION (name)] = n;
3623 bitmap_set_bit (need_assert_for, SSA_NAME_VERSION (name));
3626 /* COND is a predicate which uses NAME. Extract a suitable test code
3627 and value and store them into *CODE_P and *VAL_P so the predicate
3628 is normalized to NAME *CODE_P *VAL_P.
3630 If no extraction was possible, return FALSE, otherwise return TRUE.
3632 If INVERT is true, then we invert the result stored into *CODE_P. */
3635 extract_code_and_val_from_cond (tree name, tree cond, bool invert,
3636 enum tree_code *code_p, tree *val_p)
3638 enum tree_code comp_code;
3641 /* Predicates may be a single SSA name or NAME OP VAL. */
3644 /* If the predicate is a name, it must be NAME, in which
3645 case we create the predicate NAME == true or
3646 NAME == false accordingly. */
3647 comp_code = EQ_EXPR;
3648 val = invert ? boolean_false_node : boolean_true_node;
3652 /* Otherwise, we have a comparison of the form NAME COMP VAL
3653 or VAL COMP NAME. */
3654 if (name == TREE_OPERAND (cond, 1))
3656 /* If the predicate is of the form VAL COMP NAME, flip
3657 COMP around because we need to register NAME as the
3658 first operand in the predicate. */
3659 comp_code = swap_tree_comparison (TREE_CODE (cond));
3660 val = TREE_OPERAND (cond, 0);
3664 /* The comparison is of the form NAME COMP VAL, so the
3665 comparison code remains unchanged. */
3666 comp_code = TREE_CODE (cond);
3667 val = TREE_OPERAND (cond, 1);
3670 /* Invert the comparison code as necessary. */
3672 comp_code = invert_tree_comparison (comp_code, 0);
3674 /* VRP does not handle float types. */
3675 if (SCALAR_FLOAT_TYPE_P (TREE_TYPE (val)))
3678 /* Do not register always-false predicates.
3679 FIXME: this works around a limitation in fold() when dealing with
3680 enumerations. Given 'enum { N1, N2 } x;', fold will not
3681 fold 'if (x > N2)' to 'if (0)'. */
3682 if ((comp_code == GT_EXPR || comp_code == LT_EXPR)
3683 && INTEGRAL_TYPE_P (TREE_TYPE (val)))
3685 tree min = TYPE_MIN_VALUE (TREE_TYPE (val));
3686 tree max = TYPE_MAX_VALUE (TREE_TYPE (val));
3688 if (comp_code == GT_EXPR
3690 || compare_values (val, max) == 0))
3693 if (comp_code == LT_EXPR
3695 || compare_values (val, min) == 0))
3699 *code_p = comp_code;
3704 /* Try to register an edge assertion for SSA name NAME on edge E for
3705 the condition COND contributing to the conditional jump pointed to by BSI.
3706 Invert the condition COND if INVERT is true.
3707 Return true if an assertion for NAME could be registered. */
3710 register_edge_assert_for_2 (tree name, edge e, block_stmt_iterator bsi,
3711 tree cond, bool invert)
3714 enum tree_code comp_code;
3715 bool retval = false;
3717 if (!extract_code_and_val_from_cond (name, cond, invert, &comp_code, &val))
3720 /* Only register an ASSERT_EXPR if NAME was found in the sub-graph
3721 reachable from E. */
3722 if (TEST_BIT (found_in_subgraph, SSA_NAME_VERSION (name))
3723 && !has_single_use (name))
3725 register_new_assert_for (name, name, comp_code, val, NULL, e, bsi);
3729 /* In the case of NAME <= CST and NAME being defined as
3730 NAME = (unsigned) NAME2 + CST2 we can assert NAME2 >= -CST2
3731 and NAME2 <= CST - CST2. We can do the same for NAME > CST.
3732 This catches range and anti-range tests. */
3733 if ((comp_code == LE_EXPR
3734 || comp_code == GT_EXPR)
3735 && TREE_CODE (val) == INTEGER_CST
3736 && TYPE_UNSIGNED (TREE_TYPE (val)))
3738 tree def_stmt = SSA_NAME_DEF_STMT (name);
3739 tree cst2 = NULL_TREE, name2 = NULL_TREE;
3741 /* Extract CST2 from the (optional) addition. */
3742 if (TREE_CODE (def_stmt) == GIMPLE_MODIFY_STMT
3743 && TREE_CODE (GIMPLE_STMT_OPERAND (def_stmt, 1)) == PLUS_EXPR)
3745 name2 = TREE_OPERAND (GIMPLE_STMT_OPERAND (def_stmt, 1), 0);
3746 cst2 = TREE_OPERAND (GIMPLE_STMT_OPERAND (def_stmt, 1), 1);
3747 if (TREE_CODE (name2) == SSA_NAME
3748 && TREE_CODE (cst2) == INTEGER_CST)
3749 def_stmt = SSA_NAME_DEF_STMT (name2);
3752 /* Extract NAME2 from the (optional) cast. */
3753 if (TREE_CODE (def_stmt) == GIMPLE_MODIFY_STMT
3754 && TREE_CODE (GIMPLE_STMT_OPERAND (def_stmt, 1)) == NOP_EXPR)
3755 name2 = TREE_OPERAND (GIMPLE_STMT_OPERAND (def_stmt, 1), 0);
3757 if (name2 != NULL_TREE
3758 && TREE_CODE (name2) == SSA_NAME
3759 && (cst2 == NULL_TREE
3760 || TREE_CODE (cst2) == INTEGER_CST)
3761 && TREE_CODE (TREE_TYPE (name2)) == INTEGER_TYPE
3762 && TEST_BIT (found_in_subgraph, SSA_NAME_VERSION (name2))
3763 && !has_single_use (name2))
3767 /* Build an expression for the range test. */
3769 if (TREE_TYPE (name) != TREE_TYPE (name2))
3770 tmp = build1 (NOP_EXPR, TREE_TYPE (name), tmp);
3771 if (cst2 != NULL_TREE)
3772 tmp = build2 (PLUS_EXPR, TREE_TYPE (name), tmp, cst2);
3776 fprintf (dump_file, "Adding assert for ");
3777 print_generic_expr (dump_file, name2, 0);
3778 fprintf (dump_file, " from ");
3779 print_generic_expr (dump_file, tmp, 0);
3780 fprintf (dump_file, "\n");
3783 register_new_assert_for (name2, tmp, comp_code, val, NULL, e, bsi);
3792 /* OP is an operand of a truth value expression which is known to have
3793 a particular value. Register any asserts for OP and for any
3794 operands in OP's defining statement.
3796 If CODE is EQ_EXPR, then we want to register OP is zero (false),
3797 if CODE is NE_EXPR, then we want to register OP is nonzero (true). */
3800 register_edge_assert_for_1 (tree op, enum tree_code code,
3801 edge e, block_stmt_iterator bsi)
3803 bool retval = false;
3804 tree op_def, rhs, val;
3806 /* We only care about SSA_NAMEs. */
3807 if (TREE_CODE (op) != SSA_NAME)
3810 /* We know that OP will have a zero or nonzero value. If OP is used
3811 more than once go ahead and register an assert for OP.
3813 The FOUND_IN_SUBGRAPH support is not helpful in this situation as
3814 it will always be set for OP (because OP is used in a COND_EXPR in
3816 if (!has_single_use (op))
3818 val = build_int_cst (TREE_TYPE (op), 0);
3819 register_new_assert_for (op, op, code, val, NULL, e, bsi);
3823 /* Now look at how OP is set. If it's set from a comparison,
3824 a truth operation or some bit operations, then we may be able
3825 to register information about the operands of that assignment. */
3826 op_def = SSA_NAME_DEF_STMT (op);
3827 if (TREE_CODE (op_def) != GIMPLE_MODIFY_STMT)
3830 rhs = GIMPLE_STMT_OPERAND (op_def, 1);
3832 if (COMPARISON_CLASS_P (rhs))
3834 bool invert = (code == EQ_EXPR ? true : false);
3835 tree op0 = TREE_OPERAND (rhs, 0);
3836 tree op1 = TREE_OPERAND (rhs, 1);
3838 if (TREE_CODE (op0) == SSA_NAME)
3839 retval |= register_edge_assert_for_2 (op0, e, bsi, rhs, invert);
3840 if (TREE_CODE (op1) == SSA_NAME)
3841 retval |= register_edge_assert_for_2 (op1, e, bsi, rhs, invert);
3843 else if ((code == NE_EXPR
3844 && (TREE_CODE (rhs) == TRUTH_AND_EXPR
3845 || TREE_CODE (rhs) == BIT_AND_EXPR))
3847 && (TREE_CODE (rhs) == TRUTH_OR_EXPR
3848 || TREE_CODE (rhs) == BIT_IOR_EXPR)))
3850 /* Recurse on each operand. */
3851 retval |= register_edge_assert_for_1 (TREE_OPERAND (rhs, 0),
3853 retval |= register_edge_assert_for_1 (TREE_OPERAND (rhs, 1),
3856 else if (TREE_CODE (rhs) == TRUTH_NOT_EXPR)
3858 /* Recurse, flipping CODE. */
3859 code = invert_tree_comparison (code, false);
3860 retval |= register_edge_assert_for_1 (TREE_OPERAND (rhs, 0),
3863 else if (TREE_CODE (rhs) == SSA_NAME)
3865 /* Recurse through the copy. */
3866 retval |= register_edge_assert_for_1 (rhs, code, e, bsi);
3868 else if (TREE_CODE (rhs) == NOP_EXPR
3869 || TREE_CODE (rhs) == CONVERT_EXPR
3870 || TREE_CODE (rhs) == NON_LVALUE_EXPR)
3872 /* Recurse through the type conversion. */
3873 retval |= register_edge_assert_for_1 (TREE_OPERAND (rhs, 0),
3880 /* Try to register an edge assertion for SSA name NAME on edge E for
3881 the condition COND contributing to the conditional jump pointed to by SI.
3882 Return true if an assertion for NAME could be registered. */
3885 register_edge_assert_for (tree name, edge e, block_stmt_iterator si, tree cond)
3888 enum tree_code comp_code;
3889 bool retval = false;
3890 bool is_else_edge = (e->flags & EDGE_FALSE_VALUE) != 0;
3892 /* Do not attempt to infer anything in names that flow through
3894 if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (name))
3897 if (!extract_code_and_val_from_cond (name, cond, is_else_edge,
3901 /* Register ASSERT_EXPRs for name. */
3902 retval |= register_edge_assert_for_2 (name, e, si, cond, is_else_edge);
3905 /* If COND is effectively an equality test of an SSA_NAME against
3906 the value zero or one, then we may be able to assert values
3907 for SSA_NAMEs which flow into COND. */
3909 /* In the case of NAME == 1 or NAME != 0, for TRUTH_AND_EXPR defining
3910 statement of NAME we can assert both operands of the TRUTH_AND_EXPR
3911 have nonzero value. */
3912 if (((comp_code == EQ_EXPR && integer_onep (val))
3913 || (comp_code == NE_EXPR && integer_zerop (val))))
3915 tree def_stmt = SSA_NAME_DEF_STMT (name);
3917 if (TREE_CODE (def_stmt) == GIMPLE_MODIFY_STMT
3918 && (TREE_CODE (GIMPLE_STMT_OPERAND (def_stmt, 1)) == TRUTH_AND_EXPR
3919 || TREE_CODE (GIMPLE_STMT_OPERAND (def_stmt, 1)) == BIT_AND_EXPR))
3921 tree op0 = TREE_OPERAND (GIMPLE_STMT_OPERAND (def_stmt, 1), 0);
3922 tree op1 = TREE_OPERAND (GIMPLE_STMT_OPERAND (def_stmt, 1), 1);
3923 retval |= register_edge_assert_for_1 (op0, NE_EXPR, e, si);
3924 retval |= register_edge_assert_for_1 (op1, NE_EXPR, e, si);
3928 /* In the case of NAME == 0 or NAME != 1, for TRUTH_OR_EXPR defining
3929 statement of NAME we can assert both operands of the TRUTH_OR_EXPR
3931 if (((comp_code == EQ_EXPR && integer_zerop (val))
3932 || (comp_code == NE_EXPR && integer_onep (val))))
3934 tree def_stmt = SSA_NAME_DEF_STMT (name);
3936 if (TREE_CODE (def_stmt) == GIMPLE_MODIFY_STMT
3937 && (TREE_CODE (GIMPLE_STMT_OPERAND (def_stmt, 1)) == TRUTH_OR_EXPR
3938 /* For BIT_IOR_EXPR only if NAME == 0 both operands have
3939 necessarily zero value. */
3940 || (comp_code == EQ_EXPR
3941 && (TREE_CODE (GIMPLE_STMT_OPERAND (def_stmt, 1))
3944 tree op0 = TREE_OPERAND (GIMPLE_STMT_OPERAND (def_stmt, 1), 0);
3945 tree op1 = TREE_OPERAND (GIMPLE_STMT_OPERAND (def_stmt, 1), 1);
3946 retval |= register_edge_assert_for_1 (op0, EQ_EXPR, e, si);
3947 retval |= register_edge_assert_for_1 (op1, EQ_EXPR, e, si);
3955 static bool find_assert_locations (basic_block bb);
3957 /* Determine whether the outgoing edges of BB should receive an
3958 ASSERT_EXPR for each of the operands of BB's LAST statement.
3959 The last statement of BB must be a COND_EXPR.
3961 If any of the sub-graphs rooted at BB have an interesting use of
3962 the predicate operands, an assert location node is added to the
3963 list of assertions for the corresponding operands. */
3966 find_conditional_asserts (basic_block bb, tree last)
3969 block_stmt_iterator bsi;
3975 need_assert = false;
3976 bsi = bsi_for_stmt (last);
3978 /* Look for uses of the operands in each of the sub-graphs
3979 rooted at BB. We need to check each of the outgoing edges
3980 separately, so that we know what kind of ASSERT_EXPR to
3982 FOR_EACH_EDGE (e, ei, bb->succs)
3987 /* Remove the COND_EXPR operands from the FOUND_IN_SUBGRAPH bitmap.
3988 Otherwise, when we finish traversing each of the sub-graphs, we
3989 won't know whether the variables were found in the sub-graphs or
3990 if they had been found in a block upstream from BB.
3992 This is actually a bad idea is some cases, particularly jump
3993 threading. Consider a CFG like the following:
4003 Assume that one or more operands in the conditional at the
4004 end of block 0 are used in a conditional in block 2, but not
4005 anywhere in block 1. In this case we will not insert any
4006 assert statements in block 1, which may cause us to miss
4007 opportunities to optimize, particularly for jump threading. */
4008 FOR_EACH_SSA_TREE_OPERAND (op, last, iter, SSA_OP_USE)
4009 RESET_BIT (found_in_subgraph, SSA_NAME_VERSION (op));
4011 /* Traverse the strictly dominated sub-graph rooted at E->DEST
4012 to determine if any of the operands in the conditional
4013 predicate are used. */
4014 need_assert |= find_assert_locations (e->dest);
4016 /* Register the necessary assertions for each operand in the
4017 conditional predicate. */
4018 FOR_EACH_SSA_TREE_OPERAND (op, last, iter, SSA_OP_USE)
4019 need_assert |= register_edge_assert_for (op, e, bsi,
4020 COND_EXPR_COND (last));
4023 /* Finally, indicate that we have found the operands in the
4025 FOR_EACH_SSA_TREE_OPERAND (op, last, iter, SSA_OP_USE)
4026 SET_BIT (found_in_subgraph, SSA_NAME_VERSION (op));
4031 /* Compare two case labels sorting first by the destination label uid
4032 and then by the case value. */
4035 compare_case_labels (const void *p1, const void *p2)
4037 const_tree const case1 = *(const_tree const*)p1;
4038 const_tree const case2 = *(const_tree const*)p2;
4039 unsigned int uid1 = DECL_UID (CASE_LABEL (case1));
4040 unsigned int uid2 = DECL_UID (CASE_LABEL (case2));
4044 else if (uid1 == uid2)
4046 /* Make sure the default label is first in a group. */
4047 if (!CASE_LOW (case1))
4049 else if (!CASE_LOW (case2))
4052 return tree_int_cst_compare (CASE_LOW (case1), CASE_LOW (case2));
4058 /* Determine whether the outgoing edges of BB should receive an
4059 ASSERT_EXPR for each of the operands of BB's LAST statement.
4060 The last statement of BB must be a SWITCH_EXPR.
4062 If any of the sub-graphs rooted at BB have an interesting use of
4063 the predicate operands, an assert location node is added to the
4064 list of assertions for the corresponding operands. */
4067 find_switch_asserts (basic_block bb, tree last)
4070 block_stmt_iterator bsi;
4073 tree vec = SWITCH_LABELS (last), vec2;
4074 size_t n = TREE_VEC_LENGTH (vec);
4077 need_assert = false;
4078 bsi = bsi_for_stmt (last);
4079 op = TREE_OPERAND (last, 0);
4080 if (TREE_CODE (op) != SSA_NAME)
4083 /* Build a vector of case labels sorted by destination label. */
4084 vec2 = make_tree_vec (n);
4085 for (idx = 0; idx < n; ++idx)
4086 TREE_VEC_ELT (vec2, idx) = TREE_VEC_ELT (vec, idx);
4087 qsort (&TREE_VEC_ELT (vec2, 0), n, sizeof (tree), compare_case_labels);
4089 for (idx = 0; idx < n; ++idx)
4092 tree cl = TREE_VEC_ELT (vec2, idx);
4094 min = CASE_LOW (cl);
4095 max = CASE_HIGH (cl);
4097 /* If there are multiple case labels with the same destination
4098 we need to combine them to a single value range for the edge. */
4100 && CASE_LABEL (cl) == CASE_LABEL (TREE_VEC_ELT (vec2, idx + 1)))
4102 /* Skip labels until the last of the group. */
4106 && CASE_LABEL (cl) == CASE_LABEL (TREE_VEC_ELT (vec2, idx)));
4109 /* Pick up the maximum of the case label range. */
4110 if (CASE_HIGH (TREE_VEC_ELT (vec2, idx)))
4111 max = CASE_HIGH (TREE_VEC_ELT (vec2, idx));
4113 max = CASE_LOW (TREE_VEC_ELT (vec2, idx));
4116 /* Nothing to do if the range includes the default label until we
4117 can register anti-ranges. */
4118 if (min == NULL_TREE)
4121 /* Find the edge to register the assert expr on. */
4122 e = find_edge (bb, label_to_block (CASE_LABEL (cl)));
4124 /* Remove the SWITCH_EXPR operand from the FOUND_IN_SUBGRAPH bitmap.
4125 Otherwise, when we finish traversing each of the sub-graphs, we
4126 won't know whether the variables were found in the sub-graphs or
4127 if they had been found in a block upstream from BB. */
4128 RESET_BIT (found_in_subgraph, SSA_NAME_VERSION (op));
4130 /* Traverse the strictly dominated sub-graph rooted at E->DEST
4131 to determine if any of the operands in the conditional
4132 predicate are used. */
4134 need_assert |= find_assert_locations (e->dest);
4136 /* Register the necessary assertions for the operand in the
4138 cond = build2 (max ? GE_EXPR : EQ_EXPR, boolean_type_node,
4139 op, fold_convert (TREE_TYPE (op), min));
4140 need_assert |= register_edge_assert_for (op, e, bsi, cond);
4143 cond = build2 (LE_EXPR, boolean_type_node,
4144 op, fold_convert (TREE_TYPE (op), max));
4145 need_assert |= register_edge_assert_for (op, e, bsi, cond);
4149 /* Finally, indicate that we have found the operand in the
4151 SET_BIT (found_in_subgraph, SSA_NAME_VERSION (op));
4157 /* Traverse all the statements in block BB looking for statements that
4158 may generate useful assertions for the SSA names in their operand.
4159 If a statement produces a useful assertion A for name N_i, then the
4160 list of assertions already generated for N_i is scanned to
4161 determine if A is actually needed.
4163 If N_i already had the assertion A at a location dominating the
4164 current location, then nothing needs to be done. Otherwise, the
4165 new location for A is recorded instead.
4167 1- For every statement S in BB, all the variables used by S are
4168 added to bitmap FOUND_IN_SUBGRAPH.
4170 2- If statement S uses an operand N in a way that exposes a known
4171 value range for N, then if N was not already generated by an
4172 ASSERT_EXPR, create a new assert location for N. For instance,
4173 if N is a pointer and the statement dereferences it, we can
4174 assume that N is not NULL.
4176 3- COND_EXPRs are a special case of #2. We can derive range
4177 information from the predicate but need to insert different
4178 ASSERT_EXPRs for each of the sub-graphs rooted at the
4179 conditional block. If the last statement of BB is a conditional
4180 expression of the form 'X op Y', then
4182 a) Remove X and Y from the set FOUND_IN_SUBGRAPH.
4184 b) If the conditional is the only entry point to the sub-graph
4185 corresponding to the THEN_CLAUSE, recurse into it. On
4186 return, if X and/or Y are marked in FOUND_IN_SUBGRAPH, then
4187 an ASSERT_EXPR is added for the corresponding variable.
4189 c) Repeat step (b) on the ELSE_CLAUSE.
4191 d) Mark X and Y in FOUND_IN_SUBGRAPH.
4200 In this case, an assertion on the THEN clause is useful to
4201 determine that 'a' is always 9 on that edge. However, an assertion
4202 on the ELSE clause would be unnecessary.
4204 4- If BB does not end in a conditional expression, then we recurse
4205 into BB's dominator children.
4207 At the end of the recursive traversal, every SSA name will have a
4208 list of locations where ASSERT_EXPRs should be added. When a new
4209 location for name N is found, it is registered by calling
4210 register_new_assert_for. That function keeps track of all the
4211 registered assertions to prevent adding unnecessary assertions.
4212 For instance, if a pointer P_4 is dereferenced more than once in a
4213 dominator tree, only the location dominating all the dereference of
4214 P_4 will receive an ASSERT_EXPR.
4216 If this function returns true, then it means that there are names
4217 for which we need to generate ASSERT_EXPRs. Those assertions are
4218 inserted by process_assert_insertions. */
4221 find_assert_locations (basic_block bb)
4223 block_stmt_iterator si;
4228 if (TEST_BIT (blocks_visited, bb->index))
4231 SET_BIT (blocks_visited, bb->index);
4233 need_assert = false;
4235 /* Traverse all PHI nodes in BB marking used operands. */
4236 for (phi = phi_nodes (bb); phi; phi = PHI_CHAIN (phi))
4238 use_operand_p arg_p;
4241 FOR_EACH_PHI_ARG (arg_p, phi, i, SSA_OP_USE)
4243 tree arg = USE_FROM_PTR (arg_p);
4244 if (TREE_CODE (arg) == SSA_NAME)
4246 gcc_assert (is_gimple_reg (PHI_RESULT (phi)));
4247 SET_BIT (found_in_subgraph, SSA_NAME_VERSION (arg));
4252 /* Traverse all the statements in BB marking used names and looking
4253 for statements that may infer assertions for their used operands. */
4255 for (si = bsi_start (bb); !bsi_end_p (si); bsi_next (&si))
4260 stmt = bsi_stmt (si);
4262 /* See if we can derive an assertion for any of STMT's operands. */
4263 FOR_EACH_SSA_TREE_OPERAND (op, stmt, i, SSA_OP_USE)
4266 enum tree_code comp_code;
4268 /* Mark OP in bitmap FOUND_IN_SUBGRAPH. If STMT is inside
4269 the sub-graph of a conditional block, when we return from
4270 this recursive walk, our parent will use the
4271 FOUND_IN_SUBGRAPH bitset to determine if one of the
4272 operands it was looking for was present in the sub-graph. */
4273 SET_BIT (found_in_subgraph, SSA_NAME_VERSION (op));
4275 /* If OP is used in such a way that we can infer a value
4276 range for it, and we don't find a previous assertion for
4277 it, create a new assertion location node for OP. */
4278 if (infer_value_range (stmt, op, &comp_code, &value))
4280 /* If we are able to infer a nonzero value range for OP,
4281 then walk backwards through the use-def chain to see if OP
4282 was set via a typecast.
4284 If so, then we can also infer a nonzero value range
4285 for the operand of the NOP_EXPR. */
4286 if (comp_code == NE_EXPR && integer_zerop (value))
4289 tree def_stmt = SSA_NAME_DEF_STMT (t);
4291 while (TREE_CODE (def_stmt) == GIMPLE_MODIFY_STMT
4293 (GIMPLE_STMT_OPERAND (def_stmt, 1)) == NOP_EXPR
4295 (TREE_OPERAND (GIMPLE_STMT_OPERAND (def_stmt, 1),
4298 (TREE_TYPE (TREE_OPERAND
4299 (GIMPLE_STMT_OPERAND (def_stmt,
4302 t = TREE_OPERAND (GIMPLE_STMT_OPERAND (def_stmt, 1), 0);
4303 def_stmt = SSA_NAME_DEF_STMT (t);
4305 /* Note we want to register the assert for the
4306 operand of the NOP_EXPR after SI, not after the
4308 if (! has_single_use (t))
4310 register_new_assert_for (t, t, comp_code, value,
4317 /* If OP is used only once, namely in this STMT, don't
4318 bother creating an ASSERT_EXPR for it. Such an
4319 ASSERT_EXPR would do nothing but increase compile time. */
4320 if (!has_single_use (op))
4322 register_new_assert_for (op, op, comp_code, value,
4329 /* Remember the last statement of the block. */
4333 /* If BB's last statement is a conditional expression
4334 involving integer operands, recurse into each of the sub-graphs
4335 rooted at BB to determine if we need to add ASSERT_EXPRs. */
4337 && TREE_CODE (last) == COND_EXPR
4338 && !fp_predicate (COND_EXPR_COND (last))
4339 && !ZERO_SSA_OPERANDS (last, SSA_OP_USE))
4340 need_assert |= find_conditional_asserts (bb, last);
4343 && TREE_CODE (last) == SWITCH_EXPR
4344 && !ZERO_SSA_OPERANDS (last, SSA_OP_USE))
4345 need_assert |= find_switch_asserts (bb, last);
4347 /* Recurse into the dominator children of BB. */
4348 for (son = first_dom_son (CDI_DOMINATORS, bb);
4350 son = next_dom_son (CDI_DOMINATORS, son))
4351 need_assert |= find_assert_locations (son);
4357 /* Create an ASSERT_EXPR for NAME and insert it in the location
4358 indicated by LOC. Return true if we made any edge insertions. */
4361 process_assert_insertions_for (tree name, assert_locus_t loc)
4363 /* Build the comparison expression NAME_i COMP_CODE VAL. */
4364 tree stmt, cond, assert_expr;
4368 cond = build2 (loc->comp_code, boolean_type_node, loc->expr, loc->val);
4369 assert_expr = build_assert_expr_for (cond, name);
4373 /* We have been asked to insert the assertion on an edge. This
4374 is used only by COND_EXPR and SWITCH_EXPR assertions. */
4375 #if defined ENABLE_CHECKING
4376 gcc_assert (TREE_CODE (bsi_stmt (loc->si)) == COND_EXPR
4377 || TREE_CODE (bsi_stmt (loc->si)) == SWITCH_EXPR);
4380 bsi_insert_on_edge (loc->e, assert_expr);
4384 /* Otherwise, we can insert right after LOC->SI iff the
4385 statement must not be the last statement in the block. */
4386 stmt = bsi_stmt (loc->si);
4387 if (!stmt_ends_bb_p (stmt))
4389 bsi_insert_after (&loc->si, assert_expr, BSI_SAME_STMT);
4393 /* If STMT must be the last statement in BB, we can only insert new
4394 assertions on the non-abnormal edge out of BB. Note that since
4395 STMT is not control flow, there may only be one non-abnormal edge
4397 FOR_EACH_EDGE (e, ei, loc->bb->succs)
4398 if (!(e->flags & EDGE_ABNORMAL))
4400 bsi_insert_on_edge (e, assert_expr);
4408 /* Process all the insertions registered for every name N_i registered
4409 in NEED_ASSERT_FOR. The list of assertions to be inserted are
4410 found in ASSERTS_FOR[i]. */
4413 process_assert_insertions (void)
4417 bool update_edges_p = false;
4418 int num_asserts = 0;
4420 if (dump_file && (dump_flags & TDF_DETAILS))
4421 dump_all_asserts (dump_file);
4423 EXECUTE_IF_SET_IN_BITMAP (need_assert_for, 0, i, bi)
4425 assert_locus_t loc = asserts_for[i];
4430 assert_locus_t next = loc->next;
4431 update_edges_p |= process_assert_insertions_for (ssa_name (i), loc);
4439 bsi_commit_edge_inserts ();
4441 if (dump_file && (dump_flags & TDF_STATS))
4442 fprintf (dump_file, "\nNumber of ASSERT_EXPR expressions inserted: %d\n\n",
4447 /* Traverse the flowgraph looking for conditional jumps to insert range
4448 expressions. These range expressions are meant to provide information
4449 to optimizations that need to reason in terms of value ranges. They
4450 will not be expanded into RTL. For instance, given:
4459 this pass will transform the code into:
4465 x = ASSERT_EXPR <x, x < y>
4470 y = ASSERT_EXPR <y, x <= y>
4474 The idea is that once copy and constant propagation have run, other
4475 optimizations will be able to determine what ranges of values can 'x'
4476 take in different paths of the code, simply by checking the reaching
4477 definition of 'x'. */
4480 insert_range_assertions (void)
4486 found_in_subgraph = sbitmap_alloc (num_ssa_names);
4487 sbitmap_zero (found_in_subgraph);
4489 blocks_visited = sbitmap_alloc (last_basic_block);
4490 sbitmap_zero (blocks_visited);
4492 need_assert_for = BITMAP_ALLOC (NULL);
4493 asserts_for = XCNEWVEC (assert_locus_t, num_ssa_names);
4495 calculate_dominance_info (CDI_DOMINATORS);
4497 update_ssa_p = false;
4498 FOR_EACH_EDGE (e, ei, ENTRY_BLOCK_PTR->succs)
4499 if (find_assert_locations (e->dest))
4500 update_ssa_p = true;
4504 process_assert_insertions ();
4505 update_ssa (TODO_update_ssa_no_phi);
4508 if (dump_file && (dump_flags & TDF_DETAILS))
4510 fprintf (dump_file, "\nSSA form after inserting ASSERT_EXPRs\n");
4511 dump_function_to_file (current_function_decl, dump_file, dump_flags);
4514 sbitmap_free (found_in_subgraph);
4516 BITMAP_FREE (need_assert_for);
4519 /* Checks one ARRAY_REF in REF, located at LOCUS. Ignores flexible arrays
4520 and "struct" hacks. If VRP can determine that the
4521 array subscript is a constant, check if it is outside valid
4522 range. If the array subscript is a RANGE, warn if it is
4523 non-overlapping with valid range.
4524 IGNORE_OFF_BY_ONE is true if the ARRAY_REF is inside a ADDR_EXPR. */
4527 check_array_ref (tree ref, location_t* locus, bool ignore_off_by_one)
4529 value_range_t* vr = NULL;
4530 tree low_sub, up_sub;
4531 tree low_bound, up_bound = array_ref_up_bound (ref);
4533 low_sub = up_sub = TREE_OPERAND (ref, 1);
4535 if (!up_bound || TREE_NO_WARNING (ref)
4536 || TREE_CODE (up_bound) != INTEGER_CST
4537 /* Can not check flexible arrays. */
4538 || (TYPE_SIZE (TREE_TYPE (ref)) == NULL_TREE
4539 && TYPE_DOMAIN (TREE_TYPE (ref)) != NULL_TREE
4540 && TYPE_MAX_VALUE (TYPE_DOMAIN (TREE_TYPE (ref))) == NULL_TREE)
4541 /* Accesses after the end of arrays of size 0 (gcc
4542 extension) and 1 are likely intentional ("struct
4544 || compare_tree_int (up_bound, 1) <= 0)
4547 low_bound = array_ref_low_bound (ref);
4549 if (TREE_CODE (low_sub) == SSA_NAME)
4551 vr = get_value_range (low_sub);
4552 if (vr->type == VR_RANGE || vr->type == VR_ANTI_RANGE)
4554 low_sub = vr->type == VR_RANGE ? vr->max : vr->min;
4555 up_sub = vr->type == VR_RANGE ? vr->min : vr->max;
4559 if (vr && vr->type == VR_ANTI_RANGE)
4561 if (TREE_CODE (up_sub) == INTEGER_CST
4562 && tree_int_cst_lt (up_bound, up_sub)
4563 && TREE_CODE (low_sub) == INTEGER_CST
4564 && tree_int_cst_lt (low_sub, low_bound))
4566 warning (OPT_Warray_bounds,
4567 "%Harray subscript is outside array bounds", locus);
4568 TREE_NO_WARNING (ref) = 1;
4571 else if (TREE_CODE (up_sub) == INTEGER_CST
4572 && tree_int_cst_lt (up_bound, up_sub)
4573 && !tree_int_cst_equal (up_bound, up_sub)
4574 && (!ignore_off_by_one
4575 || !tree_int_cst_equal (int_const_binop (PLUS_EXPR,
4581 warning (OPT_Warray_bounds, "%Harray subscript is above array bounds",
4583 TREE_NO_WARNING (ref) = 1;
4585 else if (TREE_CODE (low_sub) == INTEGER_CST
4586 && tree_int_cst_lt (low_sub, low_bound))
4588 warning (OPT_Warray_bounds, "%Harray subscript is below array bounds",
4590 TREE_NO_WARNING (ref) = 1;
4594 /* Searches if the expr T, located at LOCATION computes
4595 address of an ARRAY_REF, and call check_array_ref on it. */
4598 search_for_addr_array(tree t, location_t* location)
4600 while (TREE_CODE (t) == SSA_NAME)
4602 t = SSA_NAME_DEF_STMT (t);
4603 if (TREE_CODE (t) != GIMPLE_MODIFY_STMT)
4605 t = GIMPLE_STMT_OPERAND (t, 1);
4609 /* We are only interested in addresses of ARRAY_REF's. */
4610 if (TREE_CODE (t) != ADDR_EXPR)
4613 /* Check each ARRAY_REFs in the reference chain. */
4616 if (TREE_CODE (t) == ARRAY_REF)
4617 check_array_ref (t, location, true /*ignore_off_by_one*/);
4619 t = TREE_OPERAND(t,0);
4621 while (handled_component_p (t));
4624 /* walk_tree() callback that checks if *TP is
4625 an ARRAY_REF inside an ADDR_EXPR (in which an array
4626 subscript one outside the valid range is allowed). Call
4627 check_array_ref for each ARRAY_REF found. The location is
4631 check_array_bounds (tree *tp, int *walk_subtree, void *data)
4634 tree stmt = (tree)data;
4635 location_t *location = EXPR_LOCUS (stmt);
4637 if (!EXPR_HAS_LOCATION (stmt))
4639 *walk_subtree = FALSE;
4643 *walk_subtree = TRUE;
4645 if (TREE_CODE (t) == ARRAY_REF)
4646 check_array_ref (t, location, false /*ignore_off_by_one*/);
4648 if (TREE_CODE (t) == INDIRECT_REF
4649 || (TREE_CODE (t) == RETURN_EXPR && TREE_OPERAND (t, 0)))
4650 search_for_addr_array (TREE_OPERAND (t, 0), location);
4651 else if (TREE_CODE (t) == CALL_EXPR)
4654 call_expr_arg_iterator iter;
4656 FOR_EACH_CALL_EXPR_ARG (arg, iter, t)
4657 search_for_addr_array (arg, location);
4660 if (TREE_CODE (t) == ADDR_EXPR)
4661 *walk_subtree = FALSE;
4666 /* Walk over all statements of all reachable BBs and call check_array_bounds
4670 check_all_array_refs (void)
4673 block_stmt_iterator si;
4677 /* Skip bb's that are clearly unreachable. */
4678 if (single_pred_p (bb))
4680 basic_block pred_bb = EDGE_PRED (bb, 0)->src;
4681 tree ls = NULL_TREE;
4683 if (!bsi_end_p (bsi_last (pred_bb)))
4684 ls = bsi_stmt (bsi_last (pred_bb));
4686 if (ls && TREE_CODE (ls) == COND_EXPR
4687 && ((COND_EXPR_COND (ls) == boolean_false_node
4688 && (EDGE_PRED (bb, 0)->flags & EDGE_TRUE_VALUE))
4689 || (COND_EXPR_COND (ls) == boolean_true_node
4690 && (EDGE_PRED (bb, 0)->flags & EDGE_FALSE_VALUE))))
4693 for (si = bsi_start (bb); !bsi_end_p (si); bsi_next (&si))
4694 walk_tree (bsi_stmt_ptr (si), check_array_bounds,
4695 bsi_stmt (si), NULL);
4699 /* Convert range assertion expressions into the implied copies and
4700 copy propagate away the copies. Doing the trivial copy propagation
4701 here avoids the need to run the full copy propagation pass after
4704 FIXME, this will eventually lead to copy propagation removing the
4705 names that had useful range information attached to them. For
4706 instance, if we had the assertion N_i = ASSERT_EXPR <N_j, N_j > 3>,
4707 then N_i will have the range [3, +INF].
4709 However, by converting the assertion into the implied copy
4710 operation N_i = N_j, we will then copy-propagate N_j into the uses
4711 of N_i and lose the range information. We may want to hold on to
4712 ASSERT_EXPRs a little while longer as the ranges could be used in
4713 things like jump threading.
4715 The problem with keeping ASSERT_EXPRs around is that passes after
4716 VRP need to handle them appropriately.
4718 Another approach would be to make the range information a first
4719 class property of the SSA_NAME so that it can be queried from
4720 any pass. This is made somewhat more complex by the need for
4721 multiple ranges to be associated with one SSA_NAME. */
4724 remove_range_assertions (void)
4727 block_stmt_iterator si;
4729 /* Note that the BSI iterator bump happens at the bottom of the
4730 loop and no bump is necessary if we're removing the statement
4731 referenced by the current BSI. */
4733 for (si = bsi_start (bb); !bsi_end_p (si);)
4735 tree stmt = bsi_stmt (si);
4738 if (TREE_CODE (stmt) == GIMPLE_MODIFY_STMT
4739 && TREE_CODE (GIMPLE_STMT_OPERAND (stmt, 1)) == ASSERT_EXPR)
4741 tree rhs = GIMPLE_STMT_OPERAND (stmt, 1), var;
4742 tree cond = fold (ASSERT_EXPR_COND (rhs));
4743 use_operand_p use_p;
4744 imm_use_iterator iter;
4746 gcc_assert (cond != boolean_false_node);
4748 /* Propagate the RHS into every use of the LHS. */
4749 var = ASSERT_EXPR_VAR (rhs);
4750 FOR_EACH_IMM_USE_STMT (use_stmt, iter,
4751 GIMPLE_STMT_OPERAND (stmt, 0))
4752 FOR_EACH_IMM_USE_ON_STMT (use_p, iter)
4754 SET_USE (use_p, var);
4755 gcc_assert (TREE_CODE (var) == SSA_NAME);
4758 /* And finally, remove the copy, it is not needed. */
4759 bsi_remove (&si, true);
4760 release_defs (stmt);
4766 sbitmap_free (blocks_visited);
4770 /* Return true if STMT is interesting for VRP. */
4773 stmt_interesting_for_vrp (tree stmt)
4775 if (TREE_CODE (stmt) == PHI_NODE
4776 && is_gimple_reg (PHI_RESULT (stmt))
4777 && (INTEGRAL_TYPE_P (TREE_TYPE (PHI_RESULT (stmt)))
4778 || POINTER_TYPE_P (TREE_TYPE (PHI_RESULT (stmt)))))
4780 else if (TREE_CODE (stmt) == GIMPLE_MODIFY_STMT)
4782 tree lhs = GIMPLE_STMT_OPERAND (stmt, 0);
4783 tree rhs = GIMPLE_STMT_OPERAND (stmt, 1);
4785 /* In general, assignments with virtual operands are not useful
4786 for deriving ranges, with the obvious exception of calls to
4787 builtin functions. */
4788 if (TREE_CODE (lhs) == SSA_NAME
4789 && (INTEGRAL_TYPE_P (TREE_TYPE (lhs))
4790 || POINTER_TYPE_P (TREE_TYPE (lhs)))
4791 && ((TREE_CODE (rhs) == CALL_EXPR
4792 && TREE_CODE (CALL_EXPR_FN (rhs)) == ADDR_EXPR
4793 && DECL_P (TREE_OPERAND (CALL_EXPR_FN (rhs), 0))
4794 && DECL_IS_BUILTIN (TREE_OPERAND (CALL_EXPR_FN (rhs), 0)))
4795 || ZERO_SSA_OPERANDS (stmt, SSA_OP_ALL_VIRTUALS)))
4798 else if (TREE_CODE (stmt) == COND_EXPR || TREE_CODE (stmt) == SWITCH_EXPR)
4805 /* Initialize local data structures for VRP. */
4808 vrp_initialize (void)
4812 vr_value = XCNEWVEC (value_range_t *, num_ssa_names);
4813 vr_phi_edge_counts = XCNEWVEC (int, num_ssa_names);
4817 block_stmt_iterator si;
4820 for (phi = phi_nodes (bb); phi; phi = PHI_CHAIN (phi))
4822 if (!stmt_interesting_for_vrp (phi))
4824 tree lhs = PHI_RESULT (phi);
4825 set_value_range_to_varying (get_value_range (lhs));
4826 DONT_SIMULATE_AGAIN (phi) = true;
4829 DONT_SIMULATE_AGAIN (phi) = false;
4832 for (si = bsi_start (bb); !bsi_end_p (si); bsi_next (&si))
4834 tree stmt = bsi_stmt (si);
4836 if (!stmt_interesting_for_vrp (stmt))
4840 FOR_EACH_SSA_TREE_OPERAND (def, stmt, i, SSA_OP_DEF)
4841 set_value_range_to_varying (get_value_range (def));
4842 DONT_SIMULATE_AGAIN (stmt) = true;
4846 DONT_SIMULATE_AGAIN (stmt) = false;
4853 /* Visit assignment STMT. If it produces an interesting range, record
4854 the SSA name in *OUTPUT_P. */
4856 static enum ssa_prop_result
4857 vrp_visit_assignment (tree stmt, tree *output_p)
4862 lhs = GIMPLE_STMT_OPERAND (stmt, 0);
4863 rhs = GIMPLE_STMT_OPERAND (stmt, 1);
4865 /* We only keep track of ranges in integral and pointer types. */
4866 if (TREE_CODE (lhs) == SSA_NAME
4867 && ((INTEGRAL_TYPE_P (TREE_TYPE (lhs))
4868 /* It is valid to have NULL MIN/MAX values on a type. See
4869 build_range_type. */
4870 && TYPE_MIN_VALUE (TREE_TYPE (lhs))
4871 && TYPE_MAX_VALUE (TREE_TYPE (lhs)))
4872 || POINTER_TYPE_P (TREE_TYPE (lhs))))
4875 value_range_t new_vr = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
4877 extract_range_from_expr (&new_vr, rhs);
4879 /* If STMT is inside a loop, we may be able to know something
4880 else about the range of LHS by examining scalar evolution
4882 if (current_loops && (l = loop_containing_stmt (stmt)))
4883 adjust_range_with_scev (&new_vr, l, stmt, lhs);
4885 if (update_value_range (lhs, &new_vr))
4889 if (dump_file && (dump_flags & TDF_DETAILS))
4891 fprintf (dump_file, "Found new range for ");
4892 print_generic_expr (dump_file, lhs, 0);
4893 fprintf (dump_file, ": ");
4894 dump_value_range (dump_file, &new_vr);
4895 fprintf (dump_file, "\n\n");
4898 if (new_vr.type == VR_VARYING)
4899 return SSA_PROP_VARYING;
4901 return SSA_PROP_INTERESTING;
4904 return SSA_PROP_NOT_INTERESTING;
4907 /* Every other statement produces no useful ranges. */
4908 FOR_EACH_SSA_TREE_OPERAND (def, stmt, iter, SSA_OP_DEF)
4909 set_value_range_to_varying (get_value_range (def));
4911 return SSA_PROP_VARYING;
4914 /* Helper that gets the value range of the SSA_NAME with version I
4915 or a symbolic range containing the SSA_NAME only if the value range
4916 is varying or undefined. */
4918 static inline value_range_t
4919 get_vr_for_comparison (int i)
4921 value_range_t vr = *(vr_value[i]);
4923 /* If name N_i does not have a valid range, use N_i as its own
4924 range. This allows us to compare against names that may
4925 have N_i in their ranges. */
4926 if (vr.type == VR_VARYING || vr.type == VR_UNDEFINED)
4929 vr.min = ssa_name (i);
4930 vr.max = ssa_name (i);
4936 /* Compare all the value ranges for names equivalent to VAR with VAL
4937 using comparison code COMP. Return the same value returned by
4938 compare_range_with_value, including the setting of
4939 *STRICT_OVERFLOW_P. */
4942 compare_name_with_value (enum tree_code comp, tree var, tree val,
4943 bool *strict_overflow_p)
4949 int used_strict_overflow;
4951 value_range_t equiv_vr;
4953 /* Get the set of equivalences for VAR. */
4954 e = get_value_range (var)->equiv;
4956 /* Start at -1. Set it to 0 if we do a comparison without relying
4957 on overflow, or 1 if all comparisons rely on overflow. */
4958 used_strict_overflow = -1;
4960 /* Compare vars' value range with val. */
4961 equiv_vr = get_vr_for_comparison (SSA_NAME_VERSION (var));
4963 retval = compare_range_with_value (comp, &equiv_vr, val, &sop);
4965 used_strict_overflow = sop ? 1 : 0;
4967 /* If the equiv set is empty we have done all work we need to do. */
4971 && used_strict_overflow > 0)
4972 *strict_overflow_p = true;
4976 EXECUTE_IF_SET_IN_BITMAP (e, 0, i, bi)
4978 equiv_vr = get_vr_for_comparison (i);
4980 t = compare_range_with_value (comp, &equiv_vr, val, &sop);
4983 /* If we get different answers from different members
4984 of the equivalence set this check must be in a dead
4985 code region. Folding it to a trap representation
4986 would be correct here. For now just return don't-know. */
4996 used_strict_overflow = 0;
4997 else if (used_strict_overflow < 0)
4998 used_strict_overflow = 1;
5003 && used_strict_overflow > 0)
5004 *strict_overflow_p = true;
5010 /* Given a comparison code COMP and names N1 and N2, compare all the
5011 ranges equivalent to N1 against all the ranges equivalent to N2
5012 to determine the value of N1 COMP N2. Return the same value
5013 returned by compare_ranges. Set *STRICT_OVERFLOW_P to indicate
5014 whether we relied on an overflow infinity in the comparison. */
5018 compare_names (enum tree_code comp, tree n1, tree n2,
5019 bool *strict_overflow_p)
5023 bitmap_iterator bi1, bi2;
5025 int used_strict_overflow;
5026 static bitmap_obstack *s_obstack = NULL;
5027 static bitmap s_e1 = NULL, s_e2 = NULL;
5029 /* Compare the ranges of every name equivalent to N1 against the
5030 ranges of every name equivalent to N2. */
5031 e1 = get_value_range (n1)->equiv;
5032 e2 = get_value_range (n2)->equiv;
5034 /* Use the fake bitmaps if e1 or e2 are not available. */
5035 if (s_obstack == NULL)
5037 s_obstack = XNEW (bitmap_obstack);
5038 bitmap_obstack_initialize (s_obstack);
5039 s_e1 = BITMAP_ALLOC (s_obstack);
5040 s_e2 = BITMAP_ALLOC (s_obstack);
5047 /* Add N1 and N2 to their own set of equivalences to avoid
5048 duplicating the body of the loop just to check N1 and N2
5050 bitmap_set_bit (e1, SSA_NAME_VERSION (n1));
5051 bitmap_set_bit (e2, SSA_NAME_VERSION (n2));
5053 /* If the equivalence sets have a common intersection, then the two
5054 names can be compared without checking their ranges. */
5055 if (bitmap_intersect_p (e1, e2))
5057 bitmap_clear_bit (e1, SSA_NAME_VERSION (n1));
5058 bitmap_clear_bit (e2, SSA_NAME_VERSION (n2));
5060 return (comp == EQ_EXPR || comp == GE_EXPR || comp == LE_EXPR)
5062 : boolean_false_node;
5065 /* Start at -1. Set it to 0 if we do a comparison without relying
5066 on overflow, or 1 if all comparisons rely on overflow. */
5067 used_strict_overflow = -1;
5069 /* Otherwise, compare all the equivalent ranges. First, add N1 and
5070 N2 to their own set of equivalences to avoid duplicating the body
5071 of the loop just to check N1 and N2 ranges. */
5072 EXECUTE_IF_SET_IN_BITMAP (e1, 0, i1, bi1)
5074 value_range_t vr1 = get_vr_for_comparison (i1);
5076 t = retval = NULL_TREE;
5077 EXECUTE_IF_SET_IN_BITMAP (e2, 0, i2, bi2)
5081 value_range_t vr2 = get_vr_for_comparison (i2);
5083 t = compare_ranges (comp, &vr1, &vr2, &sop);
5086 /* If we get different answers from different members
5087 of the equivalence set this check must be in a dead
5088 code region. Folding it to a trap representation
5089 would be correct here. For now just return don't-know. */
5093 bitmap_clear_bit (e1, SSA_NAME_VERSION (n1));
5094 bitmap_clear_bit (e2, SSA_NAME_VERSION (n2));
5100 used_strict_overflow = 0;
5101 else if (used_strict_overflow < 0)
5102 used_strict_overflow = 1;
5108 bitmap_clear_bit (e1, SSA_NAME_VERSION (n1));
5109 bitmap_clear_bit (e2, SSA_NAME_VERSION (n2));
5110 if (used_strict_overflow > 0)
5111 *strict_overflow_p = true;
5116 /* None of the equivalent ranges are useful in computing this
5118 bitmap_clear_bit (e1, SSA_NAME_VERSION (n1));
5119 bitmap_clear_bit (e2, SSA_NAME_VERSION (n2));
5123 /* Helper function for vrp_evaluate_conditional_warnv. */
5126 vrp_evaluate_conditional_warnv_with_ops (enum tree_code code, tree op0,
5127 tree op1, bool use_equiv_p,
5128 bool *strict_overflow_p)
5130 /* We only deal with integral and pointer types. */
5131 if (!INTEGRAL_TYPE_P (TREE_TYPE (op0))
5132 && !POINTER_TYPE_P (TREE_TYPE (op0)))
5137 if (TREE_CODE (op0) == SSA_NAME && TREE_CODE (op1) == SSA_NAME)
5138 return compare_names (code, op0, op1,
5140 else if (TREE_CODE (op0) == SSA_NAME)
5141 return compare_name_with_value (code, op0, op1,
5143 else if (TREE_CODE (op1) == SSA_NAME)
5144 return (compare_name_with_value
5145 (swap_tree_comparison (code), op1, op0,
5146 strict_overflow_p));
5150 value_range_t *vr0, *vr1;
5152 vr0 = (TREE_CODE (op0) == SSA_NAME) ? get_value_range (op0) : NULL;
5153 vr1 = (TREE_CODE (op1) == SSA_NAME) ? get_value_range (op1) : NULL;
5156 return compare_ranges (code, vr0, vr1,
5158 else if (vr0 && vr1 == NULL)
5159 return compare_range_with_value (code, vr0, op1,
5161 else if (vr0 == NULL && vr1)
5162 return (compare_range_with_value
5163 (swap_tree_comparison (code), vr1, op0,
5164 strict_overflow_p));
5169 /* Given a conditional predicate COND, try to determine if COND yields
5170 true or false based on the value ranges of its operands. Return
5171 BOOLEAN_TRUE_NODE if the conditional always evaluates to true,
5172 BOOLEAN_FALSE_NODE if the conditional always evaluates to false, and,
5173 NULL if the conditional cannot be evaluated at compile time.
5175 If USE_EQUIV_P is true, the ranges of all the names equivalent with
5176 the operands in COND are used when trying to compute its value.
5177 This is only used during final substitution. During propagation,
5178 we only check the range of each variable and not its equivalents.
5180 Set *STRICT_OVERFLOW_P to indicate whether we relied on an overflow
5181 infinity to produce the result. */
5184 vrp_evaluate_conditional_warnv (tree cond, bool use_equiv_p,
5185 bool *strict_overflow_p)
5187 gcc_assert (TREE_CODE (cond) == SSA_NAME
5188 || TREE_CODE_CLASS (TREE_CODE (cond)) == tcc_comparison);
5190 if (TREE_CODE (cond) == SSA_NAME)
5196 retval = compare_name_with_value (NE_EXPR, cond, boolean_false_node,
5200 value_range_t *vr = get_value_range (cond);
5201 retval = compare_range_with_value (NE_EXPR, vr, boolean_false_node,
5205 /* If COND has a known boolean range, return it. */
5209 /* Otherwise, if COND has a symbolic range of exactly one value,
5211 vr = get_value_range (cond);
5212 if (vr->type == VR_RANGE && vr->min == vr->max)
5216 return vrp_evaluate_conditional_warnv_with_ops (TREE_CODE (cond),
5217 TREE_OPERAND (cond, 0),
5218 TREE_OPERAND (cond, 1),
5222 /* Anything else cannot be computed statically. */
5226 /* Given COND within STMT, try to simplify it based on value range
5227 information. Return NULL if the conditional can not be evaluated.
5228 The ranges of all the names equivalent with the operands in COND
5229 will be used when trying to compute the value. If the result is
5230 based on undefined signed overflow, issue a warning if
5234 vrp_evaluate_conditional (tree cond, tree stmt)
5240 ret = vrp_evaluate_conditional_warnv (cond, true, &sop);
5244 enum warn_strict_overflow_code wc;
5245 const char* warnmsg;
5247 if (is_gimple_min_invariant (ret))
5249 wc = WARN_STRICT_OVERFLOW_CONDITIONAL;
5250 warnmsg = G_("assuming signed overflow does not occur when "
5251 "simplifying conditional to constant");
5255 wc = WARN_STRICT_OVERFLOW_COMPARISON;
5256 warnmsg = G_("assuming signed overflow does not occur when "
5257 "simplifying conditional");
5260 if (issue_strict_overflow_warning (wc))
5264 if (!EXPR_HAS_LOCATION (stmt))
5265 locus = input_location;
5267 locus = EXPR_LOCATION (stmt);
5268 warning (OPT_Wstrict_overflow, "%H%s", &locus, warnmsg);
5272 if (warn_type_limits
5274 && TREE_CODE_CLASS (TREE_CODE (cond)) == tcc_comparison)
5276 /* If the comparison is being folded and the operand on the LHS
5277 is being compared against a constant value that is outside of
5278 the natural range of OP0's type, then the predicate will
5279 always fold regardless of the value of OP0. If -Wtype-limits
5280 was specified, emit a warning. */
5281 const char *warnmsg = NULL;
5282 tree op0 = TREE_OPERAND (cond, 0);
5283 tree op1 = TREE_OPERAND (cond, 1);
5284 tree type = TREE_TYPE (op0);
5285 value_range_t *vr0 = get_value_range (op0);
5287 if (vr0->type != VR_VARYING
5288 && INTEGRAL_TYPE_P (type)
5289 && vrp_val_is_min (vr0->min)
5290 && vrp_val_is_max (vr0->max)
5291 && is_gimple_min_invariant (op1))
5293 if (integer_zerop (ret))
5294 warnmsg = G_("comparison always false due to limited range of "
5297 warnmsg = G_("comparison always true due to limited range of "
5305 if (!EXPR_HAS_LOCATION (stmt))
5306 locus = input_location;
5308 locus = EXPR_LOCATION (stmt);
5310 warning (OPT_Wtype_limits, "%H%s", &locus, warnmsg);
5318 /* Visit conditional statement STMT. If we can determine which edge
5319 will be taken out of STMT's basic block, record it in
5320 *TAKEN_EDGE_P and return SSA_PROP_INTERESTING. Otherwise, return
5321 SSA_PROP_VARYING. */
5323 static enum ssa_prop_result
5324 vrp_visit_cond_stmt (tree stmt, edge *taken_edge_p)
5329 *taken_edge_p = NULL;
5331 /* FIXME. Handle SWITCH_EXPRs. */
5332 if (TREE_CODE (stmt) == SWITCH_EXPR)
5333 return SSA_PROP_VARYING;
5335 cond = COND_EXPR_COND (stmt);
5337 if (dump_file && (dump_flags & TDF_DETAILS))
5342 fprintf (dump_file, "\nVisiting conditional with predicate: ");
5343 print_generic_expr (dump_file, cond, 0);
5344 fprintf (dump_file, "\nWith known ranges\n");
5346 FOR_EACH_SSA_TREE_OPERAND (use, stmt, i, SSA_OP_USE)
5348 fprintf (dump_file, "\t");
5349 print_generic_expr (dump_file, use, 0);
5350 fprintf (dump_file, ": ");
5351 dump_value_range (dump_file, vr_value[SSA_NAME_VERSION (use)]);
5354 fprintf (dump_file, "\n");
5357 /* Compute the value of the predicate COND by checking the known
5358 ranges of each of its operands.
5360 Note that we cannot evaluate all the equivalent ranges here
5361 because those ranges may not yet be final and with the current
5362 propagation strategy, we cannot determine when the value ranges
5363 of the names in the equivalence set have changed.
5365 For instance, given the following code fragment
5369 i_14 = ASSERT_EXPR <i_5, i_5 != 0>
5373 Assume that on the first visit to i_14, i_5 has the temporary
5374 range [8, 8] because the second argument to the PHI function is
5375 not yet executable. We derive the range ~[0, 0] for i_14 and the
5376 equivalence set { i_5 }. So, when we visit 'if (i_14 == 1)' for
5377 the first time, since i_14 is equivalent to the range [8, 8], we
5378 determine that the predicate is always false.
5380 On the next round of propagation, i_13 is determined to be
5381 VARYING, which causes i_5 to drop down to VARYING. So, another
5382 visit to i_14 is scheduled. In this second visit, we compute the
5383 exact same range and equivalence set for i_14, namely ~[0, 0] and
5384 { i_5 }. But we did not have the previous range for i_5
5385 registered, so vrp_visit_assignment thinks that the range for
5386 i_14 has not changed. Therefore, the predicate 'if (i_14 == 1)'
5387 is not visited again, which stops propagation from visiting
5388 statements in the THEN clause of that if().
5390 To properly fix this we would need to keep the previous range
5391 value for the names in the equivalence set. This way we would've
5392 discovered that from one visit to the other i_5 changed from
5393 range [8, 8] to VR_VARYING.
5395 However, fixing this apparent limitation may not be worth the
5396 additional checking. Testing on several code bases (GCC, DLV,
5397 MICO, TRAMP3D and SPEC2000) showed that doing this results in
5398 4 more predicates folded in SPEC. */
5400 val = vrp_evaluate_conditional_warnv (cond, false, &sop);
5404 *taken_edge_p = find_taken_edge (bb_for_stmt (stmt), val);
5407 if (dump_file && (dump_flags & TDF_DETAILS))
5409 "\nIgnoring predicate evaluation because "
5410 "it assumes that signed overflow is undefined");
5415 if (dump_file && (dump_flags & TDF_DETAILS))
5417 fprintf (dump_file, "\nPredicate evaluates to: ");
5418 if (val == NULL_TREE)
5419 fprintf (dump_file, "DON'T KNOW\n");
5421 print_generic_stmt (dump_file, val, 0);
5424 return (*taken_edge_p) ? SSA_PROP_INTERESTING : SSA_PROP_VARYING;
5428 /* Evaluate statement STMT. If the statement produces a useful range,
5429 return SSA_PROP_INTERESTING and record the SSA name with the
5430 interesting range into *OUTPUT_P.
5432 If STMT is a conditional branch and we can determine its truth
5433 value, the taken edge is recorded in *TAKEN_EDGE_P.
5435 If STMT produces a varying value, return SSA_PROP_VARYING. */
5437 static enum ssa_prop_result
5438 vrp_visit_stmt (tree stmt, edge *taken_edge_p, tree *output_p)
5444 if (dump_file && (dump_flags & TDF_DETAILS))
5446 fprintf (dump_file, "\nVisiting statement:\n");
5447 print_generic_stmt (dump_file, stmt, dump_flags);
5448 fprintf (dump_file, "\n");
5451 ann = stmt_ann (stmt);
5452 if (TREE_CODE (stmt) == GIMPLE_MODIFY_STMT)
5454 tree rhs = GIMPLE_STMT_OPERAND (stmt, 1);
5456 /* In general, assignments with virtual operands are not useful
5457 for deriving ranges, with the obvious exception of calls to
5458 builtin functions. */
5459 if ((TREE_CODE (rhs) == CALL_EXPR
5460 && TREE_CODE (CALL_EXPR_FN (rhs)) == ADDR_EXPR
5461 && DECL_P (TREE_OPERAND (CALL_EXPR_FN (rhs), 0))
5462 && DECL_IS_BUILTIN (TREE_OPERAND (CALL_EXPR_FN (rhs), 0)))
5463 || ZERO_SSA_OPERANDS (stmt, SSA_OP_ALL_VIRTUALS))
5464 return vrp_visit_assignment (stmt, output_p);
5466 else if (TREE_CODE (stmt) == COND_EXPR || TREE_CODE (stmt) == SWITCH_EXPR)
5467 return vrp_visit_cond_stmt (stmt, taken_edge_p);
5469 /* All other statements produce nothing of interest for VRP, so mark
5470 their outputs varying and prevent further simulation. */
5471 FOR_EACH_SSA_TREE_OPERAND (def, stmt, iter, SSA_OP_DEF)
5472 set_value_range_to_varying (get_value_range (def));
5474 return SSA_PROP_VARYING;
5478 /* Meet operation for value ranges. Given two value ranges VR0 and
5479 VR1, store in VR0 a range that contains both VR0 and VR1. This
5480 may not be the smallest possible such range. */
5483 vrp_meet (value_range_t *vr0, value_range_t *vr1)
5485 if (vr0->type == VR_UNDEFINED)
5487 copy_value_range (vr0, vr1);
5491 if (vr1->type == VR_UNDEFINED)
5493 /* Nothing to do. VR0 already has the resulting range. */
5497 if (vr0->type == VR_VARYING)
5499 /* Nothing to do. VR0 already has the resulting range. */
5503 if (vr1->type == VR_VARYING)
5505 set_value_range_to_varying (vr0);
5509 if (vr0->type == VR_RANGE && vr1->type == VR_RANGE)
5514 /* Compute the convex hull of the ranges. The lower limit of
5515 the new range is the minimum of the two ranges. If they
5516 cannot be compared, then give up. */
5517 cmp = compare_values (vr0->min, vr1->min);
5518 if (cmp == 0 || cmp == 1)
5525 /* Similarly, the upper limit of the new range is the maximum
5526 of the two ranges. If they cannot be compared, then
5528 cmp = compare_values (vr0->max, vr1->max);
5529 if (cmp == 0 || cmp == -1)
5536 /* Check for useless ranges. */
5537 if (INTEGRAL_TYPE_P (TREE_TYPE (min))
5538 && ((vrp_val_is_min (min) || is_overflow_infinity (min))
5539 && (vrp_val_is_max (max) || is_overflow_infinity (max))))
5542 /* The resulting set of equivalences is the intersection of
5544 if (vr0->equiv && vr1->equiv && vr0->equiv != vr1->equiv)
5545 bitmap_and_into (vr0->equiv, vr1->equiv);
5546 else if (vr0->equiv && !vr1->equiv)
5547 bitmap_clear (vr0->equiv);
5549 set_value_range (vr0, vr0->type, min, max, vr0->equiv);
5551 else if (vr0->type == VR_ANTI_RANGE && vr1->type == VR_ANTI_RANGE)
5553 /* Two anti-ranges meet only if their complements intersect.
5554 Only handle the case of identical ranges. */
5555 if (compare_values (vr0->min, vr1->min) == 0
5556 && compare_values (vr0->max, vr1->max) == 0
5557 && compare_values (vr0->min, vr0->max) == 0)
5559 /* The resulting set of equivalences is the intersection of
5561 if (vr0->equiv && vr1->equiv && vr0->equiv != vr1->equiv)
5562 bitmap_and_into (vr0->equiv, vr1->equiv);
5563 else if (vr0->equiv && !vr1->equiv)
5564 bitmap_clear (vr0->equiv);
5569 else if (vr0->type == VR_ANTI_RANGE || vr1->type == VR_ANTI_RANGE)
5571 /* For a numeric range [VAL1, VAL2] and an anti-range ~[VAL3, VAL4],
5572 only handle the case where the ranges have an empty intersection.
5573 The result of the meet operation is the anti-range. */
5574 if (!symbolic_range_p (vr0)
5575 && !symbolic_range_p (vr1)
5576 && !value_ranges_intersect_p (vr0, vr1))
5578 /* Copy most of VR1 into VR0. Don't copy VR1's equivalence
5579 set. We need to compute the intersection of the two
5580 equivalence sets. */
5581 if (vr1->type == VR_ANTI_RANGE)
5582 set_value_range (vr0, vr1->type, vr1->min, vr1->max, vr0->equiv);
5584 /* The resulting set of equivalences is the intersection of
5586 if (vr0->equiv && vr1->equiv && vr0->equiv != vr1->equiv)
5587 bitmap_and_into (vr0->equiv, vr1->equiv);
5588 else if (vr0->equiv && !vr1->equiv)
5589 bitmap_clear (vr0->equiv);
5600 /* Failed to find an efficient meet. Before giving up and setting
5601 the result to VARYING, see if we can at least derive a useful
5602 anti-range. FIXME, all this nonsense about distinguishing
5603 anti-ranges from ranges is necessary because of the odd
5604 semantics of range_includes_zero_p and friends. */
5605 if (!symbolic_range_p (vr0)
5606 && ((vr0->type == VR_RANGE && !range_includes_zero_p (vr0))
5607 || (vr0->type == VR_ANTI_RANGE && range_includes_zero_p (vr0)))
5608 && !symbolic_range_p (vr1)
5609 && ((vr1->type == VR_RANGE && !range_includes_zero_p (vr1))
5610 || (vr1->type == VR_ANTI_RANGE && range_includes_zero_p (vr1))))
5612 set_value_range_to_nonnull (vr0, TREE_TYPE (vr0->min));
5614 /* Since this meet operation did not result from the meeting of
5615 two equivalent names, VR0 cannot have any equivalences. */
5617 bitmap_clear (vr0->equiv);
5620 set_value_range_to_varying (vr0);
5624 /* Visit all arguments for PHI node PHI that flow through executable
5625 edges. If a valid value range can be derived from all the incoming
5626 value ranges, set a new range for the LHS of PHI. */
5628 static enum ssa_prop_result
5629 vrp_visit_phi_node (tree phi)
5632 tree lhs = PHI_RESULT (phi);
5633 value_range_t *lhs_vr = get_value_range (lhs);
5634 value_range_t vr_result = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
5635 int edges, old_edges;
5637 copy_value_range (&vr_result, lhs_vr);
5639 if (dump_file && (dump_flags & TDF_DETAILS))
5641 fprintf (dump_file, "\nVisiting PHI node: ");
5642 print_generic_expr (dump_file, phi, dump_flags);
5646 for (i = 0; i < PHI_NUM_ARGS (phi); i++)
5648 edge e = PHI_ARG_EDGE (phi, i);
5650 if (dump_file && (dump_flags & TDF_DETAILS))
5653 "\n Argument #%d (%d -> %d %sexecutable)\n",
5654 i, e->src->index, e->dest->index,
5655 (e->flags & EDGE_EXECUTABLE) ? "" : "not ");
5658 if (e->flags & EDGE_EXECUTABLE)
5660 tree arg = PHI_ARG_DEF (phi, i);
5661 value_range_t vr_arg;
5665 if (TREE_CODE (arg) == SSA_NAME)
5667 vr_arg = *(get_value_range (arg));
5671 if (is_overflow_infinity (arg))
5673 arg = copy_node (arg);
5674 TREE_OVERFLOW (arg) = 0;
5677 vr_arg.type = VR_RANGE;
5680 vr_arg.equiv = NULL;
5683 if (dump_file && (dump_flags & TDF_DETAILS))
5685 fprintf (dump_file, "\t");
5686 print_generic_expr (dump_file, arg, dump_flags);
5687 fprintf (dump_file, "\n\tValue: ");
5688 dump_value_range (dump_file, &vr_arg);
5689 fprintf (dump_file, "\n");
5692 vrp_meet (&vr_result, &vr_arg);
5694 if (vr_result.type == VR_VARYING)
5699 if (vr_result.type == VR_VARYING)
5702 old_edges = vr_phi_edge_counts[SSA_NAME_VERSION (lhs)];
5703 vr_phi_edge_counts[SSA_NAME_VERSION (lhs)] = edges;
5705 /* To prevent infinite iterations in the algorithm, derive ranges
5706 when the new value is slightly bigger or smaller than the
5707 previous one. We don't do this if we have seen a new executable
5708 edge; this helps us avoid an overflow infinity for conditionals
5709 which are not in a loop. */
5710 if (lhs_vr->type == VR_RANGE && vr_result.type == VR_RANGE
5711 && edges <= old_edges)
5713 if (!POINTER_TYPE_P (TREE_TYPE (lhs)))
5715 int cmp_min = compare_values (lhs_vr->min, vr_result.min);
5716 int cmp_max = compare_values (lhs_vr->max, vr_result.max);
5718 /* If the new minimum is smaller or larger than the previous
5719 one, go all the way to -INF. In the first case, to avoid
5720 iterating millions of times to reach -INF, and in the
5721 other case to avoid infinite bouncing between different
5723 if (cmp_min > 0 || cmp_min < 0)
5725 /* If we will end up with a (-INF, +INF) range, set it
5727 if (vrp_val_is_max (vr_result.max))
5730 if (!needs_overflow_infinity (TREE_TYPE (vr_result.min))
5731 || !vrp_var_may_overflow (lhs, phi))
5732 vr_result.min = TYPE_MIN_VALUE (TREE_TYPE (vr_result.min));
5733 else if (supports_overflow_infinity (TREE_TYPE (vr_result.min)))
5735 negative_overflow_infinity (TREE_TYPE (vr_result.min));
5740 /* Similarly, if the new maximum is smaller or larger than
5741 the previous one, go all the way to +INF. */
5742 if (cmp_max < 0 || cmp_max > 0)
5744 /* If we will end up with a (-INF, +INF) range, set it
5746 if (vrp_val_is_min (vr_result.min))
5749 if (!needs_overflow_infinity (TREE_TYPE (vr_result.max))
5750 || !vrp_var_may_overflow (lhs, phi))
5751 vr_result.max = TYPE_MAX_VALUE (TREE_TYPE (vr_result.max));
5752 else if (supports_overflow_infinity (TREE_TYPE (vr_result.max)))
5754 positive_overflow_infinity (TREE_TYPE (vr_result.max));
5761 /* If the new range is different than the previous value, keep
5763 if (update_value_range (lhs, &vr_result))
5764 return SSA_PROP_INTERESTING;
5766 /* Nothing changed, don't add outgoing edges. */
5767 return SSA_PROP_NOT_INTERESTING;
5769 /* No match found. Set the LHS to VARYING. */
5771 set_value_range_to_varying (lhs_vr);
5772 return SSA_PROP_VARYING;
5775 /* Simplify a division or modulo operator to a right shift or
5776 bitwise and if the first operand is unsigned or is greater
5777 than zero and the second operand is an exact power of two. */
5780 simplify_div_or_mod_using_ranges (tree stmt, tree rhs, enum tree_code rhs_code)
5783 tree op = TREE_OPERAND (rhs, 0);
5784 value_range_t *vr = get_value_range (TREE_OPERAND (rhs, 0));
5786 if (TYPE_UNSIGNED (TREE_TYPE (op)))
5788 val = integer_one_node;
5794 val = compare_range_with_value (GE_EXPR, vr, integer_zero_node, &sop);
5798 && integer_onep (val)
5799 && issue_strict_overflow_warning (WARN_STRICT_OVERFLOW_MISC))
5803 if (!EXPR_HAS_LOCATION (stmt))
5804 locus = input_location;
5806 locus = EXPR_LOCATION (stmt);
5807 warning (OPT_Wstrict_overflow,
5808 ("%Hassuming signed overflow does not occur when "
5809 "simplifying / or %% to >> or &"),
5814 if (val && integer_onep (val))
5817 tree op0 = TREE_OPERAND (rhs, 0);
5818 tree op1 = TREE_OPERAND (rhs, 1);
5820 if (rhs_code == TRUNC_DIV_EXPR)
5822 t = build_int_cst (NULL_TREE, tree_log2 (op1));
5823 t = build2 (RSHIFT_EXPR, TREE_TYPE (op0), op0, t);
5827 t = build_int_cst (TREE_TYPE (op1), 1);
5828 t = int_const_binop (MINUS_EXPR, op1, t, 0);
5829 t = fold_convert (TREE_TYPE (op0), t);
5830 t = build2 (BIT_AND_EXPR, TREE_TYPE (op0), op0, t);
5833 GIMPLE_STMT_OPERAND (stmt, 1) = t;
5838 /* If the operand to an ABS_EXPR is >= 0, then eliminate the
5839 ABS_EXPR. If the operand is <= 0, then simplify the
5840 ABS_EXPR into a NEGATE_EXPR. */
5843 simplify_abs_using_ranges (tree stmt, tree rhs)
5846 tree op = TREE_OPERAND (rhs, 0);
5847 tree type = TREE_TYPE (op);
5848 value_range_t *vr = get_value_range (TREE_OPERAND (rhs, 0));
5850 if (TYPE_UNSIGNED (type))
5852 val = integer_zero_node;
5858 val = compare_range_with_value (LE_EXPR, vr, integer_zero_node, &sop);
5862 val = compare_range_with_value (GE_EXPR, vr, integer_zero_node,
5867 if (integer_zerop (val))
5868 val = integer_one_node;
5869 else if (integer_onep (val))
5870 val = integer_zero_node;
5875 && (integer_onep (val) || integer_zerop (val)))
5879 if (sop && issue_strict_overflow_warning (WARN_STRICT_OVERFLOW_MISC))
5883 if (!EXPR_HAS_LOCATION (stmt))
5884 locus = input_location;
5886 locus = EXPR_LOCATION (stmt);
5887 warning (OPT_Wstrict_overflow,
5888 ("%Hassuming signed overflow does not occur when "
5889 "simplifying abs (X) to X or -X"),
5893 if (integer_onep (val))
5894 t = build1 (NEGATE_EXPR, TREE_TYPE (op), op);
5898 GIMPLE_STMT_OPERAND (stmt, 1) = t;
5904 /* We are comparing trees OP0 and OP1 using COND_CODE. OP0 has
5905 a known value range VR.
5907 If there is one and only one value which will satisfy the
5908 conditional, then return that value. Else return NULL. */
5911 test_for_singularity (enum tree_code cond_code, tree op0,
5912 tree op1, value_range_t *vr)
5917 /* Extract minimum/maximum values which satisfy the
5918 the conditional as it was written. */
5919 if (cond_code == LE_EXPR || cond_code == LT_EXPR)
5921 /* This should not be negative infinity; there is no overflow
5923 min = TYPE_MIN_VALUE (TREE_TYPE (op0));
5926 if (cond_code == LT_EXPR && !is_overflow_infinity (max))
5928 tree one = build_int_cst (TREE_TYPE (op0), 1);
5929 max = fold_build2 (MINUS_EXPR, TREE_TYPE (op0), max, one);
5931 TREE_NO_WARNING (max) = 1;
5934 else if (cond_code == GE_EXPR || cond_code == GT_EXPR)
5936 /* This should not be positive infinity; there is no overflow
5938 max = TYPE_MAX_VALUE (TREE_TYPE (op0));
5941 if (cond_code == GT_EXPR && !is_overflow_infinity (min))
5943 tree one = build_int_cst (TREE_TYPE (op0), 1);
5944 min = fold_build2 (PLUS_EXPR, TREE_TYPE (op0), min, one);
5946 TREE_NO_WARNING (min) = 1;
5950 /* Now refine the minimum and maximum values using any
5951 value range information we have for op0. */
5954 if (compare_values (vr->min, min) == -1)
5958 if (compare_values (vr->max, max) == 1)
5963 /* If the new min/max values have converged to a single value,
5964 then there is only one value which can satisfy the condition,
5965 return that value. */
5966 if (operand_equal_p (min, max, 0) && is_gimple_min_invariant (min))
5972 /* Simplify a conditional using a relational operator to an equality
5973 test if the range information indicates only one value can satisfy
5974 the original conditional. */
5977 simplify_cond_using_ranges (tree stmt)
5979 tree cond = COND_EXPR_COND (stmt);
5980 tree op0 = TREE_OPERAND (cond, 0);
5981 tree op1 = TREE_OPERAND (cond, 1);
5982 enum tree_code cond_code = TREE_CODE (cond);
5984 if (cond_code != NE_EXPR
5985 && cond_code != EQ_EXPR
5986 && TREE_CODE (op0) == SSA_NAME
5987 && INTEGRAL_TYPE_P (TREE_TYPE (op0))
5988 && is_gimple_min_invariant (op1))
5990 value_range_t *vr = get_value_range (op0);
5992 /* If we have range information for OP0, then we might be
5993 able to simplify this conditional. */
5994 if (vr->type == VR_RANGE)
5996 tree new = test_for_singularity (cond_code, op0, op1, vr);
6002 fprintf (dump_file, "Simplified relational ");
6003 print_generic_expr (dump_file, cond, 0);
6004 fprintf (dump_file, " into ");
6007 COND_EXPR_COND (stmt)
6008 = build2 (EQ_EXPR, boolean_type_node, op0, new);
6013 print_generic_expr (dump_file, COND_EXPR_COND (stmt), 0);
6014 fprintf (dump_file, "\n");
6020 /* Try again after inverting the condition. We only deal
6021 with integral types here, so no need to worry about
6022 issues with inverting FP comparisons. */
6023 cond_code = invert_tree_comparison (cond_code, false);
6024 new = test_for_singularity (cond_code, op0, op1, vr);
6030 fprintf (dump_file, "Simplified relational ");
6031 print_generic_expr (dump_file, cond, 0);
6032 fprintf (dump_file, " into ");
6035 COND_EXPR_COND (stmt)
6036 = build2 (NE_EXPR, boolean_type_node, op0, new);
6041 print_generic_expr (dump_file, COND_EXPR_COND (stmt), 0);
6042 fprintf (dump_file, "\n");
6051 /* Simplify STMT using ranges if possible. */
6054 simplify_stmt_using_ranges (tree stmt)
6056 if (TREE_CODE (stmt) == GIMPLE_MODIFY_STMT)
6058 tree rhs = GIMPLE_STMT_OPERAND (stmt, 1);
6059 enum tree_code rhs_code = TREE_CODE (rhs);
6061 /* Transform TRUNC_DIV_EXPR and TRUNC_MOD_EXPR into RSHIFT_EXPR
6062 and BIT_AND_EXPR respectively if the first operand is greater
6063 than zero and the second operand is an exact power of two. */
6064 if ((rhs_code == TRUNC_DIV_EXPR || rhs_code == TRUNC_MOD_EXPR)
6065 && INTEGRAL_TYPE_P (TREE_TYPE (TREE_OPERAND (rhs, 0)))
6066 && integer_pow2p (TREE_OPERAND (rhs, 1)))
6067 simplify_div_or_mod_using_ranges (stmt, rhs, rhs_code);
6069 /* Transform ABS (X) into X or -X as appropriate. */
6070 if (rhs_code == ABS_EXPR
6071 && TREE_CODE (TREE_OPERAND (rhs, 0)) == SSA_NAME
6072 && INTEGRAL_TYPE_P (TREE_TYPE (TREE_OPERAND (rhs, 0))))
6073 simplify_abs_using_ranges (stmt, rhs);
6075 else if (TREE_CODE (stmt) == COND_EXPR
6076 && COMPARISON_CLASS_P (COND_EXPR_COND (stmt)))
6078 simplify_cond_using_ranges (stmt);
6082 /* Stack of dest,src equivalency pairs that need to be restored after
6083 each attempt to thread a block's incoming edge to an outgoing edge.
6085 A NULL entry is used to mark the end of pairs which need to be
6087 static VEC(tree,heap) *stack;
6089 /* A trivial wrapper so that we can present the generic jump threading
6090 code with a simple API for simplifying statements. STMT is the
6091 statement we want to simplify, WITHIN_STMT provides the location
6092 for any overflow warnings. */
6095 simplify_stmt_for_jump_threading (tree stmt, tree within_stmt)
6097 /* We only use VRP information to simplify conditionals. This is
6098 overly conservative, but it's unclear if doing more would be
6099 worth the compile time cost. */
6100 if (TREE_CODE (stmt) != COND_EXPR)
6103 return vrp_evaluate_conditional (COND_EXPR_COND (stmt), within_stmt);
6106 /* Blocks which have more than one predecessor and more than
6107 one successor present jump threading opportunities. ie,
6108 when the block is reached from a specific predecessor, we
6109 may be able to determine which of the outgoing edges will
6110 be traversed. When this optimization applies, we are able
6111 to avoid conditionals at runtime and we may expose secondary
6112 optimization opportunities.
6114 This routine is effectively a driver for the generic jump
6115 threading code. It basically just presents the generic code
6116 with edges that may be suitable for jump threading.
6118 Unlike DOM, we do not iterate VRP if jump threading was successful.
6119 While iterating may expose new opportunities for VRP, it is expected
6120 those opportunities would be very limited and the compile time cost
6121 to expose those opportunities would be significant.
6123 As jump threading opportunities are discovered, they are registered
6124 for later realization. */
6127 identify_jump_threads (void)
6132 /* Ugh. When substituting values earlier in this pass we can
6133 wipe the dominance information. So rebuild the dominator
6134 information as we need it within the jump threading code. */
6135 calculate_dominance_info (CDI_DOMINATORS);
6137 /* We do not allow VRP information to be used for jump threading
6138 across a back edge in the CFG. Otherwise it becomes too
6139 difficult to avoid eliminating loop exit tests. Of course
6140 EDGE_DFS_BACK is not accurate at this time so we have to
6142 mark_dfs_back_edges ();
6144 /* Allocate our unwinder stack to unwind any temporary equivalences
6145 that might be recorded. */
6146 stack = VEC_alloc (tree, heap, 20);
6148 /* To avoid lots of silly node creation, we create a single
6149 conditional and just modify it in-place when attempting to
6151 dummy = build2 (EQ_EXPR, boolean_type_node, NULL, NULL);
6152 dummy = build3 (COND_EXPR, void_type_node, dummy, NULL, NULL);
6154 /* Walk through all the blocks finding those which present a
6155 potential jump threading opportunity. We could set this up
6156 as a dominator walker and record data during the walk, but
6157 I doubt it's worth the effort for the classes of jump
6158 threading opportunities we are trying to identify at this
6159 point in compilation. */
6164 /* If the generic jump threading code does not find this block
6165 interesting, then there is nothing to do. */
6166 if (! potentially_threadable_block (bb))
6169 /* We only care about blocks ending in a COND_EXPR. While there
6170 may be some value in handling SWITCH_EXPR here, I doubt it's
6171 terribly important. */
6172 last = bsi_stmt (bsi_last (bb));
6173 if (TREE_CODE (last) != COND_EXPR)
6176 /* We're basically looking for any kind of conditional with
6177 integral type arguments. */
6178 cond = COND_EXPR_COND (last);
6179 if ((TREE_CODE (cond) == SSA_NAME
6180 && INTEGRAL_TYPE_P (TREE_TYPE (cond)))
6181 || (COMPARISON_CLASS_P (cond)
6182 && TREE_CODE (TREE_OPERAND (cond, 0)) == SSA_NAME
6183 && INTEGRAL_TYPE_P (TREE_TYPE (TREE_OPERAND (cond, 0)))
6184 && (TREE_CODE (TREE_OPERAND (cond, 1)) == SSA_NAME
6185 || is_gimple_min_invariant (TREE_OPERAND (cond, 1)))
6186 && INTEGRAL_TYPE_P (TREE_TYPE (TREE_OPERAND (cond, 1)))))
6191 /* We've got a block with multiple predecessors and multiple
6192 successors which also ends in a suitable conditional. For
6193 each predecessor, see if we can thread it to a specific
6195 FOR_EACH_EDGE (e, ei, bb->preds)
6197 /* Do not thread across back edges or abnormal edges
6199 if (e->flags & (EDGE_DFS_BACK | EDGE_COMPLEX))
6202 thread_across_edge (dummy, e, true,
6204 simplify_stmt_for_jump_threading);
6209 /* We do not actually update the CFG or SSA graphs at this point as
6210 ASSERT_EXPRs are still in the IL and cfg cleanup code does not yet
6211 handle ASSERT_EXPRs gracefully. */
6214 /* We identified all the jump threading opportunities earlier, but could
6215 not transform the CFG at that time. This routine transforms the
6216 CFG and arranges for the dominator tree to be rebuilt if necessary.
6218 Note the SSA graph update will occur during the normal TODO
6219 processing by the pass manager. */
6221 finalize_jump_threads (void)
6223 thread_through_all_blocks (false);
6224 VEC_free (tree, heap, stack);
6228 /* Traverse all the blocks folding conditionals with known ranges. */
6234 prop_value_t *single_val_range;
6235 bool do_value_subst_p;
6239 fprintf (dump_file, "\nValue ranges after VRP:\n\n");
6240 dump_all_value_ranges (dump_file);
6241 fprintf (dump_file, "\n");
6244 /* We may have ended with ranges that have exactly one value. Those
6245 values can be substituted as any other copy/const propagated
6246 value using substitute_and_fold. */
6247 single_val_range = XCNEWVEC (prop_value_t, num_ssa_names);
6249 do_value_subst_p = false;
6250 for (i = 0; i < num_ssa_names; i++)
6252 && vr_value[i]->type == VR_RANGE
6253 && vr_value[i]->min == vr_value[i]->max)
6255 single_val_range[i].value = vr_value[i]->min;
6256 do_value_subst_p = true;
6259 if (!do_value_subst_p)
6261 /* We found no single-valued ranges, don't waste time trying to
6262 do single value substitution in substitute_and_fold. */
6263 free (single_val_range);
6264 single_val_range = NULL;
6267 substitute_and_fold (single_val_range, true);
6269 if (warn_array_bounds)
6270 check_all_array_refs ();
6272 /* We must identify jump threading opportunities before we release
6273 the datastructures built by VRP. */
6274 identify_jump_threads ();
6276 /* Free allocated memory. */
6277 for (i = 0; i < num_ssa_names; i++)
6280 BITMAP_FREE (vr_value[i]->equiv);
6284 free (single_val_range);
6286 free (vr_phi_edge_counts);
6288 /* So that we can distinguish between VRP data being available
6289 and not available. */
6291 vr_phi_edge_counts = NULL;
6294 /* Calculates number of iterations for all loops, to ensure that they are
6298 record_numbers_of_iterations (void)
6303 FOR_EACH_LOOP (li, loop, 0)
6305 number_of_latch_executions (loop);
6309 /* Main entry point to VRP (Value Range Propagation). This pass is
6310 loosely based on J. R. C. Patterson, ``Accurate Static Branch
6311 Prediction by Value Range Propagation,'' in SIGPLAN Conference on
6312 Programming Language Design and Implementation, pp. 67-78, 1995.
6313 Also available at http://citeseer.ist.psu.edu/patterson95accurate.html
6315 This is essentially an SSA-CCP pass modified to deal with ranges
6316 instead of constants.
6318 While propagating ranges, we may find that two or more SSA name
6319 have equivalent, though distinct ranges. For instance,
6322 2 p_4 = ASSERT_EXPR <p_3, p_3 != 0>
6324 4 p_5 = ASSERT_EXPR <p_4, p_4 == q_2>;
6328 In the code above, pointer p_5 has range [q_2, q_2], but from the
6329 code we can also determine that p_5 cannot be NULL and, if q_2 had
6330 a non-varying range, p_5's range should also be compatible with it.
6332 These equivalences are created by two expressions: ASSERT_EXPR and
6333 copy operations. Since p_5 is an assertion on p_4, and p_4 was the
6334 result of another assertion, then we can use the fact that p_5 and
6335 p_4 are equivalent when evaluating p_5's range.
6337 Together with value ranges, we also propagate these equivalences
6338 between names so that we can take advantage of information from
6339 multiple ranges when doing final replacement. Note that this
6340 equivalency relation is transitive but not symmetric.
6342 In the example above, p_5 is equivalent to p_4, q_2 and p_3, but we
6343 cannot assert that q_2 is equivalent to p_5 because q_2 may be used
6344 in contexts where that assertion does not hold (e.g., in line 6).
6346 TODO, the main difference between this pass and Patterson's is that
6347 we do not propagate edge probabilities. We only compute whether
6348 edges can be taken or not. That is, instead of having a spectrum
6349 of jump probabilities between 0 and 1, we only deal with 0, 1 and
6350 DON'T KNOW. In the future, it may be worthwhile to propagate
6351 probabilities to aid branch prediction. */
6356 loop_optimizer_init (LOOPS_NORMAL | LOOPS_HAVE_RECORDED_EXITS);
6357 rewrite_into_loop_closed_ssa (NULL, TODO_update_ssa);
6360 insert_range_assertions ();
6362 /* Compute the # of iterations for each loop before we start the VRP
6363 analysis. The value ranges determined by VRP are used in expression
6364 simplification, that is also used by the # of iterations analysis.
6365 However, in the middle of the VRP analysis, the value ranges do not take
6366 all the possible paths in CFG into account, so they do not have to be
6367 correct, and the # of iterations analysis can obtain wrong results.
6368 This is a problem, since the results of the # of iterations analysis
6369 are cached, so these mistakes would not be corrected when the value
6370 ranges are corrected. */
6371 record_numbers_of_iterations ();
6374 ssa_propagate (vrp_visit_stmt, vrp_visit_phi_node);
6377 /* ASSERT_EXPRs must be removed before finalizing jump threads
6378 as finalizing jump threads calls the CFG cleanup code which
6379 does not properly handle ASSERT_EXPRs. */
6380 remove_range_assertions ();
6382 /* If we exposed any new variables, go ahead and put them into
6383 SSA form now, before we handle jump threading. This simplifies
6384 interactions between rewriting of _DECL nodes into SSA form
6385 and rewriting SSA_NAME nodes into SSA form after block
6386 duplication and CFG manipulation. */
6387 update_ssa (TODO_update_ssa);
6389 finalize_jump_threads ();
6391 loop_optimizer_finalize ();
6399 return flag_tree_vrp != 0;
6402 struct gimple_opt_pass pass_vrp =
6407 gate_vrp, /* gate */
6408 execute_vrp, /* execute */
6411 0, /* static_pass_number */
6412 TV_TREE_VRP, /* tv_id */
6413 PROP_ssa | PROP_alias, /* properties_required */
6414 0, /* properties_provided */
6415 0, /* properties_destroyed */
6416 0, /* todo_flags_start */
6421 | TODO_update_ssa /* todo_flags_finish */