1 /* Support routines for Value Range Propagation (VRP).
2 Copyright (C) 2005, 2006, 2007, 2008, 2009, 2010, 2011
3 Free Software Foundation, Inc.
4 Contributed by Diego Novillo <dnovillo@redhat.com>.
6 This file is part of GCC.
8 GCC is free software; you can redistribute it and/or modify
9 it under the terms of the GNU General Public License as published by
10 the Free Software Foundation; either version 3, or (at your option)
13 GCC is distributed in the hope that it will be useful,
14 but WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 GNU General Public License for more details.
18 You should have received a copy of the GNU General Public License
19 along with GCC; see the file COPYING3. If not see
20 <http://www.gnu.org/licenses/>. */
24 #include "coretypes.h"
29 #include "basic-block.h"
30 #include "tree-flow.h"
31 #include "tree-pass.h"
32 #include "tree-dump.h"
34 #include "tree-pretty-print.h"
35 #include "gimple-pretty-print.h"
36 #include "diagnostic-core.h"
39 #include "tree-scalar-evolution.h"
40 #include "tree-ssa-propagate.h"
41 #include "tree-chrec.h"
42 #include "gimple-fold.h"
47 /* Type of value ranges. See value_range_d for a description of these
49 enum value_range_type { VR_UNDEFINED, VR_RANGE, VR_ANTI_RANGE, VR_VARYING };
51 /* Range of values that can be associated with an SSA_NAME after VRP
55 /* Lattice value represented by this range. */
56 enum value_range_type type;
58 /* Minimum and maximum values represented by this range. These
59 values should be interpreted as follows:
61 - If TYPE is VR_UNDEFINED or VR_VARYING then MIN and MAX must
64 - If TYPE == VR_RANGE then MIN holds the minimum value and
65 MAX holds the maximum value of the range [MIN, MAX].
67 - If TYPE == ANTI_RANGE the variable is known to NOT
68 take any values in the range [MIN, MAX]. */
72 /* Set of SSA names whose value ranges are equivalent to this one.
73 This set is only valid when TYPE is VR_RANGE or VR_ANTI_RANGE. */
77 typedef struct value_range_d value_range_t;
79 /* Set of SSA names found live during the RPO traversal of the function
80 for still active basic-blocks. */
83 /* Return true if the SSA name NAME is live on the edge E. */
86 live_on_edge (edge e, tree name)
88 return (live[e->dest->index]
89 && TEST_BIT (live[e->dest->index], SSA_NAME_VERSION (name)));
92 /* Local functions. */
93 static int compare_values (tree val1, tree val2);
94 static int compare_values_warnv (tree val1, tree val2, bool *);
95 static void vrp_meet (value_range_t *, value_range_t *);
96 static tree vrp_evaluate_conditional_warnv_with_ops (enum tree_code,
97 tree, tree, bool, bool *,
100 /* Location information for ASSERT_EXPRs. Each instance of this
101 structure describes an ASSERT_EXPR for an SSA name. Since a single
102 SSA name may have more than one assertion associated with it, these
103 locations are kept in a linked list attached to the corresponding
105 struct assert_locus_d
107 /* Basic block where the assertion would be inserted. */
110 /* Some assertions need to be inserted on an edge (e.g., assertions
111 generated by COND_EXPRs). In those cases, BB will be NULL. */
114 /* Pointer to the statement that generated this assertion. */
115 gimple_stmt_iterator si;
117 /* Predicate code for the ASSERT_EXPR. Must be COMPARISON_CLASS_P. */
118 enum tree_code comp_code;
120 /* Value being compared against. */
123 /* Expression to compare. */
126 /* Next node in the linked list. */
127 struct assert_locus_d *next;
130 typedef struct assert_locus_d *assert_locus_t;
132 /* If bit I is present, it means that SSA name N_i has a list of
133 assertions that should be inserted in the IL. */
134 static bitmap need_assert_for;
136 /* Array of locations lists where to insert assertions. ASSERTS_FOR[I]
137 holds a list of ASSERT_LOCUS_T nodes that describe where
138 ASSERT_EXPRs for SSA name N_I should be inserted. */
139 static assert_locus_t *asserts_for;
141 /* Value range array. After propagation, VR_VALUE[I] holds the range
142 of values that SSA name N_I may take. */
143 static unsigned num_vr_values;
144 static value_range_t **vr_value;
145 static bool values_propagated;
147 /* For a PHI node which sets SSA name N_I, VR_COUNTS[I] holds the
148 number of executable edges we saw the last time we visited the
150 static int *vr_phi_edge_counts;
157 static VEC (edge, heap) *to_remove_edges;
158 DEF_VEC_O(switch_update);
159 DEF_VEC_ALLOC_O(switch_update, heap);
160 static VEC (switch_update, heap) *to_update_switch_stmts;
163 /* Return the maximum value for TYPE. */
166 vrp_val_max (const_tree type)
168 if (!INTEGRAL_TYPE_P (type))
171 return TYPE_MAX_VALUE (type);
174 /* Return the minimum value for TYPE. */
177 vrp_val_min (const_tree type)
179 if (!INTEGRAL_TYPE_P (type))
182 return TYPE_MIN_VALUE (type);
185 /* Return whether VAL is equal to the maximum value of its type. This
186 will be true for a positive overflow infinity. We can't do a
187 simple equality comparison with TYPE_MAX_VALUE because C typedefs
188 and Ada subtypes can produce types whose TYPE_MAX_VALUE is not ==
189 to the integer constant with the same value in the type. */
192 vrp_val_is_max (const_tree val)
194 tree type_max = vrp_val_max (TREE_TYPE (val));
195 return (val == type_max
196 || (type_max != NULL_TREE
197 && operand_equal_p (val, type_max, 0)));
200 /* Return whether VAL is equal to the minimum value of its type. This
201 will be true for a negative overflow infinity. */
204 vrp_val_is_min (const_tree val)
206 tree type_min = vrp_val_min (TREE_TYPE (val));
207 return (val == type_min
208 || (type_min != NULL_TREE
209 && operand_equal_p (val, type_min, 0)));
213 /* Return whether TYPE should use an overflow infinity distinct from
214 TYPE_{MIN,MAX}_VALUE. We use an overflow infinity value to
215 represent a signed overflow during VRP computations. An infinity
216 is distinct from a half-range, which will go from some number to
217 TYPE_{MIN,MAX}_VALUE. */
220 needs_overflow_infinity (const_tree type)
222 return INTEGRAL_TYPE_P (type) && !TYPE_OVERFLOW_WRAPS (type);
225 /* Return whether TYPE can support our overflow infinity
226 representation: we use the TREE_OVERFLOW flag, which only exists
227 for constants. If TYPE doesn't support this, we don't optimize
228 cases which would require signed overflow--we drop them to
232 supports_overflow_infinity (const_tree type)
234 tree min = vrp_val_min (type), max = vrp_val_max (type);
235 #ifdef ENABLE_CHECKING
236 gcc_assert (needs_overflow_infinity (type));
238 return (min != NULL_TREE
239 && CONSTANT_CLASS_P (min)
241 && CONSTANT_CLASS_P (max));
244 /* VAL is the maximum or minimum value of a type. Return a
245 corresponding overflow infinity. */
248 make_overflow_infinity (tree val)
250 gcc_checking_assert (val != NULL_TREE && CONSTANT_CLASS_P (val));
251 val = copy_node (val);
252 TREE_OVERFLOW (val) = 1;
256 /* Return a negative overflow infinity for TYPE. */
259 negative_overflow_infinity (tree type)
261 gcc_checking_assert (supports_overflow_infinity (type));
262 return make_overflow_infinity (vrp_val_min (type));
265 /* Return a positive overflow infinity for TYPE. */
268 positive_overflow_infinity (tree type)
270 gcc_checking_assert (supports_overflow_infinity (type));
271 return make_overflow_infinity (vrp_val_max (type));
274 /* Return whether VAL is a negative overflow infinity. */
277 is_negative_overflow_infinity (const_tree val)
279 return (needs_overflow_infinity (TREE_TYPE (val))
280 && CONSTANT_CLASS_P (val)
281 && TREE_OVERFLOW (val)
282 && vrp_val_is_min (val));
285 /* Return whether VAL is a positive overflow infinity. */
288 is_positive_overflow_infinity (const_tree val)
290 return (needs_overflow_infinity (TREE_TYPE (val))
291 && CONSTANT_CLASS_P (val)
292 && TREE_OVERFLOW (val)
293 && vrp_val_is_max (val));
296 /* Return whether VAL is a positive or negative overflow infinity. */
299 is_overflow_infinity (const_tree val)
301 return (needs_overflow_infinity (TREE_TYPE (val))
302 && CONSTANT_CLASS_P (val)
303 && TREE_OVERFLOW (val)
304 && (vrp_val_is_min (val) || vrp_val_is_max (val)));
307 /* Return whether STMT has a constant rhs that is_overflow_infinity. */
310 stmt_overflow_infinity (gimple stmt)
312 if (is_gimple_assign (stmt)
313 && get_gimple_rhs_class (gimple_assign_rhs_code (stmt)) ==
315 return is_overflow_infinity (gimple_assign_rhs1 (stmt));
319 /* If VAL is now an overflow infinity, return VAL. Otherwise, return
320 the same value with TREE_OVERFLOW clear. This can be used to avoid
321 confusing a regular value with an overflow value. */
324 avoid_overflow_infinity (tree val)
326 if (!is_overflow_infinity (val))
329 if (vrp_val_is_max (val))
330 return vrp_val_max (TREE_TYPE (val));
333 gcc_checking_assert (vrp_val_is_min (val));
334 return vrp_val_min (TREE_TYPE (val));
339 /* Return true if ARG is marked with the nonnull attribute in the
340 current function signature. */
343 nonnull_arg_p (const_tree arg)
345 tree t, attrs, fntype;
346 unsigned HOST_WIDE_INT arg_num;
348 gcc_assert (TREE_CODE (arg) == PARM_DECL && POINTER_TYPE_P (TREE_TYPE (arg)));
350 /* The static chain decl is always non null. */
351 if (arg == cfun->static_chain_decl)
354 fntype = TREE_TYPE (current_function_decl);
355 attrs = lookup_attribute ("nonnull", TYPE_ATTRIBUTES (fntype));
357 /* If "nonnull" wasn't specified, we know nothing about the argument. */
358 if (attrs == NULL_TREE)
361 /* If "nonnull" applies to all the arguments, then ARG is non-null. */
362 if (TREE_VALUE (attrs) == NULL_TREE)
365 /* Get the position number for ARG in the function signature. */
366 for (arg_num = 1, t = DECL_ARGUMENTS (current_function_decl);
368 t = DECL_CHAIN (t), arg_num++)
374 gcc_assert (t == arg);
376 /* Now see if ARG_NUM is mentioned in the nonnull list. */
377 for (t = TREE_VALUE (attrs); t; t = TREE_CHAIN (t))
379 if (compare_tree_int (TREE_VALUE (t), arg_num) == 0)
387 /* Set value range VR to VR_VARYING. */
390 set_value_range_to_varying (value_range_t *vr)
392 vr->type = VR_VARYING;
393 vr->min = vr->max = NULL_TREE;
395 bitmap_clear (vr->equiv);
399 /* Set value range VR to {T, MIN, MAX, EQUIV}. */
402 set_value_range (value_range_t *vr, enum value_range_type t, tree min,
403 tree max, bitmap equiv)
405 #if defined ENABLE_CHECKING
406 /* Check the validity of the range. */
407 if (t == VR_RANGE || t == VR_ANTI_RANGE)
411 gcc_assert (min && max);
413 if (INTEGRAL_TYPE_P (TREE_TYPE (min)) && t == VR_ANTI_RANGE)
414 gcc_assert (!vrp_val_is_min (min) || !vrp_val_is_max (max));
416 cmp = compare_values (min, max);
417 gcc_assert (cmp == 0 || cmp == -1 || cmp == -2);
419 if (needs_overflow_infinity (TREE_TYPE (min)))
420 gcc_assert (!is_overflow_infinity (min)
421 || !is_overflow_infinity (max));
424 if (t == VR_UNDEFINED || t == VR_VARYING)
425 gcc_assert (min == NULL_TREE && max == NULL_TREE);
427 if (t == VR_UNDEFINED || t == VR_VARYING)
428 gcc_assert (equiv == NULL || bitmap_empty_p (equiv));
435 /* Since updating the equivalence set involves deep copying the
436 bitmaps, only do it if absolutely necessary. */
437 if (vr->equiv == NULL
439 vr->equiv = BITMAP_ALLOC (NULL);
441 if (equiv != vr->equiv)
443 if (equiv && !bitmap_empty_p (equiv))
444 bitmap_copy (vr->equiv, equiv);
446 bitmap_clear (vr->equiv);
451 /* Set value range VR to the canonical form of {T, MIN, MAX, EQUIV}.
452 This means adjusting T, MIN and MAX representing the case of a
453 wrapping range with MAX < MIN covering [MIN, type_max] U [type_min, MAX]
454 as anti-rage ~[MAX+1, MIN-1]. Likewise for wrapping anti-ranges.
455 In corner cases where MAX+1 or MIN-1 wraps this will fall back
457 This routine exists to ease canonicalization in the case where we
458 extract ranges from var + CST op limit. */
461 set_and_canonicalize_value_range (value_range_t *vr, enum value_range_type t,
462 tree min, tree max, bitmap equiv)
464 /* Nothing to canonicalize for symbolic or unknown or varying ranges. */
466 && t != VR_ANTI_RANGE)
467 || TREE_CODE (min) != INTEGER_CST
468 || TREE_CODE (max) != INTEGER_CST)
470 set_value_range (vr, t, min, max, equiv);
474 /* Wrong order for min and max, to swap them and the VR type we need
476 if (tree_int_cst_lt (max, min))
478 tree one = build_int_cst (TREE_TYPE (min), 1);
479 tree tmp = int_const_binop (PLUS_EXPR, max, one);
480 max = int_const_binop (MINUS_EXPR, min, one);
483 /* There's one corner case, if we had [C+1, C] before we now have
484 that again. But this represents an empty value range, so drop
485 to varying in this case. */
486 if (tree_int_cst_lt (max, min))
488 set_value_range_to_varying (vr);
492 t = t == VR_RANGE ? VR_ANTI_RANGE : VR_RANGE;
495 /* Anti-ranges that can be represented as ranges should be so. */
496 if (t == VR_ANTI_RANGE)
498 bool is_min = vrp_val_is_min (min);
499 bool is_max = vrp_val_is_max (max);
501 if (is_min && is_max)
503 /* We cannot deal with empty ranges, drop to varying. */
504 set_value_range_to_varying (vr);
508 /* As a special exception preserve non-null ranges. */
509 && !(TYPE_UNSIGNED (TREE_TYPE (min))
510 && integer_zerop (max)))
512 tree one = build_int_cst (TREE_TYPE (max), 1);
513 min = int_const_binop (PLUS_EXPR, max, one);
514 max = vrp_val_max (TREE_TYPE (max));
519 tree one = build_int_cst (TREE_TYPE (min), 1);
520 max = int_const_binop (MINUS_EXPR, min, one);
521 min = vrp_val_min (TREE_TYPE (min));
526 set_value_range (vr, t, min, max, equiv);
529 /* Copy value range FROM into value range TO. */
532 copy_value_range (value_range_t *to, value_range_t *from)
534 set_value_range (to, from->type, from->min, from->max, from->equiv);
537 /* Set value range VR to a single value. This function is only called
538 with values we get from statements, and exists to clear the
539 TREE_OVERFLOW flag so that we don't think we have an overflow
540 infinity when we shouldn't. */
543 set_value_range_to_value (value_range_t *vr, tree val, bitmap equiv)
545 gcc_assert (is_gimple_min_invariant (val));
546 val = avoid_overflow_infinity (val);
547 set_value_range (vr, VR_RANGE, val, val, equiv);
550 /* Set value range VR to a non-negative range of type TYPE.
551 OVERFLOW_INFINITY indicates whether to use an overflow infinity
552 rather than TYPE_MAX_VALUE; this should be true if we determine
553 that the range is nonnegative based on the assumption that signed
554 overflow does not occur. */
557 set_value_range_to_nonnegative (value_range_t *vr, tree type,
558 bool overflow_infinity)
562 if (overflow_infinity && !supports_overflow_infinity (type))
564 set_value_range_to_varying (vr);
568 zero = build_int_cst (type, 0);
569 set_value_range (vr, VR_RANGE, zero,
571 ? positive_overflow_infinity (type)
572 : TYPE_MAX_VALUE (type)),
576 /* Set value range VR to a non-NULL range of type TYPE. */
579 set_value_range_to_nonnull (value_range_t *vr, tree type)
581 tree zero = build_int_cst (type, 0);
582 set_value_range (vr, VR_ANTI_RANGE, zero, zero, vr->equiv);
586 /* Set value range VR to a NULL range of type TYPE. */
589 set_value_range_to_null (value_range_t *vr, tree type)
591 set_value_range_to_value (vr, build_int_cst (type, 0), vr->equiv);
595 /* Set value range VR to a range of a truthvalue of type TYPE. */
598 set_value_range_to_truthvalue (value_range_t *vr, tree type)
600 if (TYPE_PRECISION (type) == 1)
601 set_value_range_to_varying (vr);
603 set_value_range (vr, VR_RANGE,
604 build_int_cst (type, 0), build_int_cst (type, 1),
609 /* Set value range VR to VR_UNDEFINED. */
612 set_value_range_to_undefined (value_range_t *vr)
614 vr->type = VR_UNDEFINED;
615 vr->min = vr->max = NULL_TREE;
617 bitmap_clear (vr->equiv);
621 /* If abs (min) < abs (max), set VR to [-max, max], if
622 abs (min) >= abs (max), set VR to [-min, min]. */
625 abs_extent_range (value_range_t *vr, tree min, tree max)
629 gcc_assert (TREE_CODE (min) == INTEGER_CST);
630 gcc_assert (TREE_CODE (max) == INTEGER_CST);
631 gcc_assert (INTEGRAL_TYPE_P (TREE_TYPE (min)));
632 gcc_assert (!TYPE_UNSIGNED (TREE_TYPE (min)));
633 min = fold_unary (ABS_EXPR, TREE_TYPE (min), min);
634 max = fold_unary (ABS_EXPR, TREE_TYPE (max), max);
635 if (TREE_OVERFLOW (min) || TREE_OVERFLOW (max))
637 set_value_range_to_varying (vr);
640 cmp = compare_values (min, max);
642 min = fold_unary (NEGATE_EXPR, TREE_TYPE (min), max);
643 else if (cmp == 0 || cmp == 1)
646 min = fold_unary (NEGATE_EXPR, TREE_TYPE (min), min);
650 set_value_range_to_varying (vr);
653 set_and_canonicalize_value_range (vr, VR_RANGE, min, max, NULL);
657 /* Return value range information for VAR.
659 If we have no values ranges recorded (ie, VRP is not running), then
660 return NULL. Otherwise create an empty range if none existed for VAR. */
662 static value_range_t *
663 get_value_range (const_tree var)
665 static const struct value_range_d vr_const_varying
666 = { VR_VARYING, NULL_TREE, NULL_TREE, NULL };
669 unsigned ver = SSA_NAME_VERSION (var);
671 /* If we have no recorded ranges, then return NULL. */
675 /* If we query the range for a new SSA name return an unmodifiable VARYING.
676 We should get here at most from the substitute-and-fold stage which
677 will never try to change values. */
678 if (ver >= num_vr_values)
679 return CONST_CAST (value_range_t *, &vr_const_varying);
685 /* After propagation finished do not allocate new value-ranges. */
686 if (values_propagated)
687 return CONST_CAST (value_range_t *, &vr_const_varying);
689 /* Create a default value range. */
690 vr_value[ver] = vr = XCNEW (value_range_t);
692 /* Defer allocating the equivalence set. */
695 /* If VAR is a default definition, the variable can take any value
697 sym = SSA_NAME_VAR (var);
698 if (SSA_NAME_IS_DEFAULT_DEF (var))
700 /* Try to use the "nonnull" attribute to create ~[0, 0]
701 anti-ranges for pointers. Note that this is only valid with
702 default definitions of PARM_DECLs. */
703 if (TREE_CODE (sym) == PARM_DECL
704 && POINTER_TYPE_P (TREE_TYPE (sym))
705 && nonnull_arg_p (sym))
706 set_value_range_to_nonnull (vr, TREE_TYPE (sym));
708 set_value_range_to_varying (vr);
714 /* Return true, if VAL1 and VAL2 are equal values for VRP purposes. */
717 vrp_operand_equal_p (const_tree val1, const_tree val2)
721 if (!val1 || !val2 || !operand_equal_p (val1, val2, 0))
723 if (is_overflow_infinity (val1))
724 return is_overflow_infinity (val2);
728 /* Return true, if the bitmaps B1 and B2 are equal. */
731 vrp_bitmap_equal_p (const_bitmap b1, const_bitmap b2)
734 || ((!b1 || bitmap_empty_p (b1))
735 && (!b2 || bitmap_empty_p (b2)))
737 && bitmap_equal_p (b1, b2)));
740 /* Update the value range and equivalence set for variable VAR to
741 NEW_VR. Return true if NEW_VR is different from VAR's previous
744 NOTE: This function assumes that NEW_VR is a temporary value range
745 object created for the sole purpose of updating VAR's range. The
746 storage used by the equivalence set from NEW_VR will be freed by
747 this function. Do not call update_value_range when NEW_VR
748 is the range object associated with another SSA name. */
751 update_value_range (const_tree var, value_range_t *new_vr)
753 value_range_t *old_vr;
756 /* Update the value range, if necessary. */
757 old_vr = get_value_range (var);
758 is_new = old_vr->type != new_vr->type
759 || !vrp_operand_equal_p (old_vr->min, new_vr->min)
760 || !vrp_operand_equal_p (old_vr->max, new_vr->max)
761 || !vrp_bitmap_equal_p (old_vr->equiv, new_vr->equiv);
764 set_value_range (old_vr, new_vr->type, new_vr->min, new_vr->max,
767 BITMAP_FREE (new_vr->equiv);
773 /* Add VAR and VAR's equivalence set to EQUIV. This is the central
774 point where equivalence processing can be turned on/off. */
777 add_equivalence (bitmap *equiv, const_tree var)
779 unsigned ver = SSA_NAME_VERSION (var);
780 value_range_t *vr = vr_value[ver];
783 *equiv = BITMAP_ALLOC (NULL);
784 bitmap_set_bit (*equiv, ver);
786 bitmap_ior_into (*equiv, vr->equiv);
790 /* Return true if VR is ~[0, 0]. */
793 range_is_nonnull (value_range_t *vr)
795 return vr->type == VR_ANTI_RANGE
796 && integer_zerop (vr->min)
797 && integer_zerop (vr->max);
801 /* Return true if VR is [0, 0]. */
804 range_is_null (value_range_t *vr)
806 return vr->type == VR_RANGE
807 && integer_zerop (vr->min)
808 && integer_zerop (vr->max);
811 /* Return true if max and min of VR are INTEGER_CST. It's not necessary
815 range_int_cst_p (value_range_t *vr)
817 return (vr->type == VR_RANGE
818 && TREE_CODE (vr->max) == INTEGER_CST
819 && TREE_CODE (vr->min) == INTEGER_CST
820 && !TREE_OVERFLOW (vr->max)
821 && !TREE_OVERFLOW (vr->min));
824 /* Return true if VR is a INTEGER_CST singleton. */
827 range_int_cst_singleton_p (value_range_t *vr)
829 return (range_int_cst_p (vr)
830 && tree_int_cst_equal (vr->min, vr->max));
833 /* Return true if value range VR involves at least one symbol. */
836 symbolic_range_p (value_range_t *vr)
838 return (!is_gimple_min_invariant (vr->min)
839 || !is_gimple_min_invariant (vr->max));
842 /* Return true if value range VR uses an overflow infinity. */
845 overflow_infinity_range_p (value_range_t *vr)
847 return (vr->type == VR_RANGE
848 && (is_overflow_infinity (vr->min)
849 || is_overflow_infinity (vr->max)));
852 /* Return false if we can not make a valid comparison based on VR;
853 this will be the case if it uses an overflow infinity and overflow
854 is not undefined (i.e., -fno-strict-overflow is in effect).
855 Otherwise return true, and set *STRICT_OVERFLOW_P to true if VR
856 uses an overflow infinity. */
859 usable_range_p (value_range_t *vr, bool *strict_overflow_p)
861 gcc_assert (vr->type == VR_RANGE);
862 if (is_overflow_infinity (vr->min))
864 *strict_overflow_p = true;
865 if (!TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (vr->min)))
868 if (is_overflow_infinity (vr->max))
870 *strict_overflow_p = true;
871 if (!TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (vr->max)))
878 /* Like tree_expr_nonnegative_warnv_p, but this function uses value
879 ranges obtained so far. */
882 vrp_expr_computes_nonnegative (tree expr, bool *strict_overflow_p)
884 return (tree_expr_nonnegative_warnv_p (expr, strict_overflow_p)
885 || (TREE_CODE (expr) == SSA_NAME
886 && ssa_name_nonnegative_p (expr)));
889 /* Return true if the result of assignment STMT is know to be non-negative.
890 If the return value is based on the assumption that signed overflow is
891 undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't change
892 *STRICT_OVERFLOW_P.*/
895 gimple_assign_nonnegative_warnv_p (gimple stmt, bool *strict_overflow_p)
897 enum tree_code code = gimple_assign_rhs_code (stmt);
898 switch (get_gimple_rhs_class (code))
900 case GIMPLE_UNARY_RHS:
901 return tree_unary_nonnegative_warnv_p (gimple_assign_rhs_code (stmt),
902 gimple_expr_type (stmt),
903 gimple_assign_rhs1 (stmt),
905 case GIMPLE_BINARY_RHS:
906 return tree_binary_nonnegative_warnv_p (gimple_assign_rhs_code (stmt),
907 gimple_expr_type (stmt),
908 gimple_assign_rhs1 (stmt),
909 gimple_assign_rhs2 (stmt),
911 case GIMPLE_TERNARY_RHS:
913 case GIMPLE_SINGLE_RHS:
914 return tree_single_nonnegative_warnv_p (gimple_assign_rhs1 (stmt),
916 case GIMPLE_INVALID_RHS:
923 /* Return true if return value of call STMT is know to be non-negative.
924 If the return value is based on the assumption that signed overflow is
925 undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't change
926 *STRICT_OVERFLOW_P.*/
929 gimple_call_nonnegative_warnv_p (gimple stmt, bool *strict_overflow_p)
931 tree arg0 = gimple_call_num_args (stmt) > 0 ?
932 gimple_call_arg (stmt, 0) : NULL_TREE;
933 tree arg1 = gimple_call_num_args (stmt) > 1 ?
934 gimple_call_arg (stmt, 1) : NULL_TREE;
936 return tree_call_nonnegative_warnv_p (gimple_expr_type (stmt),
937 gimple_call_fndecl (stmt),
943 /* Return true if STMT is know to to compute a non-negative value.
944 If the return value is based on the assumption that signed overflow is
945 undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't change
946 *STRICT_OVERFLOW_P.*/
949 gimple_stmt_nonnegative_warnv_p (gimple stmt, bool *strict_overflow_p)
951 switch (gimple_code (stmt))
954 return gimple_assign_nonnegative_warnv_p (stmt, strict_overflow_p);
956 return gimple_call_nonnegative_warnv_p (stmt, strict_overflow_p);
962 /* Return true if the result of assignment STMT is know to be non-zero.
963 If the return value is based on the assumption that signed overflow is
964 undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't change
965 *STRICT_OVERFLOW_P.*/
968 gimple_assign_nonzero_warnv_p (gimple stmt, bool *strict_overflow_p)
970 enum tree_code code = gimple_assign_rhs_code (stmt);
971 switch (get_gimple_rhs_class (code))
973 case GIMPLE_UNARY_RHS:
974 return tree_unary_nonzero_warnv_p (gimple_assign_rhs_code (stmt),
975 gimple_expr_type (stmt),
976 gimple_assign_rhs1 (stmt),
978 case GIMPLE_BINARY_RHS:
979 return tree_binary_nonzero_warnv_p (gimple_assign_rhs_code (stmt),
980 gimple_expr_type (stmt),
981 gimple_assign_rhs1 (stmt),
982 gimple_assign_rhs2 (stmt),
984 case GIMPLE_TERNARY_RHS:
986 case GIMPLE_SINGLE_RHS:
987 return tree_single_nonzero_warnv_p (gimple_assign_rhs1 (stmt),
989 case GIMPLE_INVALID_RHS:
996 /* Return true if STMT is know to to compute a non-zero value.
997 If the return value is based on the assumption that signed overflow is
998 undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't change
999 *STRICT_OVERFLOW_P.*/
1002 gimple_stmt_nonzero_warnv_p (gimple stmt, bool *strict_overflow_p)
1004 switch (gimple_code (stmt))
1007 return gimple_assign_nonzero_warnv_p (stmt, strict_overflow_p);
1009 return gimple_alloca_call_p (stmt);
1015 /* Like tree_expr_nonzero_warnv_p, but this function uses value ranges
1019 vrp_stmt_computes_nonzero (gimple stmt, bool *strict_overflow_p)
1021 if (gimple_stmt_nonzero_warnv_p (stmt, strict_overflow_p))
1024 /* If we have an expression of the form &X->a, then the expression
1025 is nonnull if X is nonnull. */
1026 if (is_gimple_assign (stmt)
1027 && gimple_assign_rhs_code (stmt) == ADDR_EXPR)
1029 tree expr = gimple_assign_rhs1 (stmt);
1030 tree base = get_base_address (TREE_OPERAND (expr, 0));
1032 if (base != NULL_TREE
1033 && TREE_CODE (base) == MEM_REF
1034 && TREE_CODE (TREE_OPERAND (base, 0)) == SSA_NAME)
1036 value_range_t *vr = get_value_range (TREE_OPERAND (base, 0));
1037 if (range_is_nonnull (vr))
1045 /* Returns true if EXPR is a valid value (as expected by compare_values) --
1046 a gimple invariant, or SSA_NAME +- CST. */
1049 valid_value_p (tree expr)
1051 if (TREE_CODE (expr) == SSA_NAME)
1054 if (TREE_CODE (expr) == PLUS_EXPR
1055 || TREE_CODE (expr) == MINUS_EXPR)
1056 return (TREE_CODE (TREE_OPERAND (expr, 0)) == SSA_NAME
1057 && TREE_CODE (TREE_OPERAND (expr, 1)) == INTEGER_CST);
1059 return is_gimple_min_invariant (expr);
1065 -2 if those are incomparable. */
1067 operand_less_p (tree val, tree val2)
1069 /* LT is folded faster than GE and others. Inline the common case. */
1070 if (TREE_CODE (val) == INTEGER_CST && TREE_CODE (val2) == INTEGER_CST)
1072 if (TYPE_UNSIGNED (TREE_TYPE (val)))
1073 return INT_CST_LT_UNSIGNED (val, val2);
1076 if (INT_CST_LT (val, val2))
1084 fold_defer_overflow_warnings ();
1086 tcmp = fold_binary_to_constant (LT_EXPR, boolean_type_node, val, val2);
1088 fold_undefer_and_ignore_overflow_warnings ();
1091 || TREE_CODE (tcmp) != INTEGER_CST)
1094 if (!integer_zerop (tcmp))
1098 /* val >= val2, not considering overflow infinity. */
1099 if (is_negative_overflow_infinity (val))
1100 return is_negative_overflow_infinity (val2) ? 0 : 1;
1101 else if (is_positive_overflow_infinity (val2))
1102 return is_positive_overflow_infinity (val) ? 0 : 1;
1107 /* Compare two values VAL1 and VAL2. Return
1109 -2 if VAL1 and VAL2 cannot be compared at compile-time,
1112 +1 if VAL1 > VAL2, and
1115 This is similar to tree_int_cst_compare but supports pointer values
1116 and values that cannot be compared at compile time.
1118 If STRICT_OVERFLOW_P is not NULL, then set *STRICT_OVERFLOW_P to
1119 true if the return value is only valid if we assume that signed
1120 overflow is undefined. */
1123 compare_values_warnv (tree val1, tree val2, bool *strict_overflow_p)
1128 /* Below we rely on the fact that VAL1 and VAL2 are both pointers or
1130 gcc_assert (POINTER_TYPE_P (TREE_TYPE (val1))
1131 == POINTER_TYPE_P (TREE_TYPE (val2)));
1132 /* Convert the two values into the same type. This is needed because
1133 sizetype causes sign extension even for unsigned types. */
1134 val2 = fold_convert (TREE_TYPE (val1), val2);
1135 STRIP_USELESS_TYPE_CONVERSION (val2);
1137 if ((TREE_CODE (val1) == SSA_NAME
1138 || TREE_CODE (val1) == PLUS_EXPR
1139 || TREE_CODE (val1) == MINUS_EXPR)
1140 && (TREE_CODE (val2) == SSA_NAME
1141 || TREE_CODE (val2) == PLUS_EXPR
1142 || TREE_CODE (val2) == MINUS_EXPR))
1144 tree n1, c1, n2, c2;
1145 enum tree_code code1, code2;
1147 /* If VAL1 and VAL2 are of the form 'NAME [+-] CST' or 'NAME',
1148 return -1 or +1 accordingly. If VAL1 and VAL2 don't use the
1149 same name, return -2. */
1150 if (TREE_CODE (val1) == SSA_NAME)
1158 code1 = TREE_CODE (val1);
1159 n1 = TREE_OPERAND (val1, 0);
1160 c1 = TREE_OPERAND (val1, 1);
1161 if (tree_int_cst_sgn (c1) == -1)
1163 if (is_negative_overflow_infinity (c1))
1165 c1 = fold_unary_to_constant (NEGATE_EXPR, TREE_TYPE (c1), c1);
1168 code1 = code1 == MINUS_EXPR ? PLUS_EXPR : MINUS_EXPR;
1172 if (TREE_CODE (val2) == SSA_NAME)
1180 code2 = TREE_CODE (val2);
1181 n2 = TREE_OPERAND (val2, 0);
1182 c2 = TREE_OPERAND (val2, 1);
1183 if (tree_int_cst_sgn (c2) == -1)
1185 if (is_negative_overflow_infinity (c2))
1187 c2 = fold_unary_to_constant (NEGATE_EXPR, TREE_TYPE (c2), c2);
1190 code2 = code2 == MINUS_EXPR ? PLUS_EXPR : MINUS_EXPR;
1194 /* Both values must use the same name. */
1198 if (code1 == SSA_NAME
1199 && code2 == SSA_NAME)
1203 /* If overflow is defined we cannot simplify more. */
1204 if (!TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (val1)))
1207 if (strict_overflow_p != NULL
1208 && (code1 == SSA_NAME || !TREE_NO_WARNING (val1))
1209 && (code2 == SSA_NAME || !TREE_NO_WARNING (val2)))
1210 *strict_overflow_p = true;
1212 if (code1 == SSA_NAME)
1214 if (code2 == PLUS_EXPR)
1215 /* NAME < NAME + CST */
1217 else if (code2 == MINUS_EXPR)
1218 /* NAME > NAME - CST */
1221 else if (code1 == PLUS_EXPR)
1223 if (code2 == SSA_NAME)
1224 /* NAME + CST > NAME */
1226 else if (code2 == PLUS_EXPR)
1227 /* NAME + CST1 > NAME + CST2, if CST1 > CST2 */
1228 return compare_values_warnv (c1, c2, strict_overflow_p);
1229 else if (code2 == MINUS_EXPR)
1230 /* NAME + CST1 > NAME - CST2 */
1233 else if (code1 == MINUS_EXPR)
1235 if (code2 == SSA_NAME)
1236 /* NAME - CST < NAME */
1238 else if (code2 == PLUS_EXPR)
1239 /* NAME - CST1 < NAME + CST2 */
1241 else if (code2 == MINUS_EXPR)
1242 /* NAME - CST1 > NAME - CST2, if CST1 < CST2. Notice that
1243 C1 and C2 are swapped in the call to compare_values. */
1244 return compare_values_warnv (c2, c1, strict_overflow_p);
1250 /* We cannot compare non-constants. */
1251 if (!is_gimple_min_invariant (val1) || !is_gimple_min_invariant (val2))
1254 if (!POINTER_TYPE_P (TREE_TYPE (val1)))
1256 /* We cannot compare overflowed values, except for overflow
1258 if (TREE_OVERFLOW (val1) || TREE_OVERFLOW (val2))
1260 if (strict_overflow_p != NULL)
1261 *strict_overflow_p = true;
1262 if (is_negative_overflow_infinity (val1))
1263 return is_negative_overflow_infinity (val2) ? 0 : -1;
1264 else if (is_negative_overflow_infinity (val2))
1266 else if (is_positive_overflow_infinity (val1))
1267 return is_positive_overflow_infinity (val2) ? 0 : 1;
1268 else if (is_positive_overflow_infinity (val2))
1273 return tree_int_cst_compare (val1, val2);
1279 /* First see if VAL1 and VAL2 are not the same. */
1280 if (val1 == val2 || operand_equal_p (val1, val2, 0))
1283 /* If VAL1 is a lower address than VAL2, return -1. */
1284 if (operand_less_p (val1, val2) == 1)
1287 /* If VAL1 is a higher address than VAL2, return +1. */
1288 if (operand_less_p (val2, val1) == 1)
1291 /* If VAL1 is different than VAL2, return +2.
1292 For integer constants we either have already returned -1 or 1
1293 or they are equivalent. We still might succeed in proving
1294 something about non-trivial operands. */
1295 if (TREE_CODE (val1) != INTEGER_CST
1296 || TREE_CODE (val2) != INTEGER_CST)
1298 t = fold_binary_to_constant (NE_EXPR, boolean_type_node, val1, val2);
1299 if (t && integer_onep (t))
1307 /* Compare values like compare_values_warnv, but treat comparisons of
1308 nonconstants which rely on undefined overflow as incomparable. */
1311 compare_values (tree val1, tree val2)
1317 ret = compare_values_warnv (val1, val2, &sop);
1319 && (!is_gimple_min_invariant (val1) || !is_gimple_min_invariant (val2)))
1325 /* Return 1 if VAL is inside value range VR (VR->MIN <= VAL <= VR->MAX),
1326 0 if VAL is not inside VR,
1327 -2 if we cannot tell either way.
1329 FIXME, the current semantics of this functions are a bit quirky
1330 when taken in the context of VRP. In here we do not care
1331 about VR's type. If VR is the anti-range ~[3, 5] the call
1332 value_inside_range (4, VR) will return 1.
1334 This is counter-intuitive in a strict sense, but the callers
1335 currently expect this. They are calling the function
1336 merely to determine whether VR->MIN <= VAL <= VR->MAX. The
1337 callers are applying the VR_RANGE/VR_ANTI_RANGE semantics
1340 This also applies to value_ranges_intersect_p and
1341 range_includes_zero_p. The semantics of VR_RANGE and
1342 VR_ANTI_RANGE should be encoded here, but that also means
1343 adapting the users of these functions to the new semantics.
1345 Benchmark compile/20001226-1.c compilation time after changing this
1349 value_inside_range (tree val, value_range_t * vr)
1353 cmp1 = operand_less_p (val, vr->min);
1359 cmp2 = operand_less_p (vr->max, val);
1367 /* Return true if value ranges VR0 and VR1 have a non-empty
1370 Benchmark compile/20001226-1.c compilation time after changing this
1375 value_ranges_intersect_p (value_range_t *vr0, value_range_t *vr1)
1377 /* The value ranges do not intersect if the maximum of the first range is
1378 less than the minimum of the second range or vice versa.
1379 When those relations are unknown, we can't do any better. */
1380 if (operand_less_p (vr0->max, vr1->min) != 0)
1382 if (operand_less_p (vr1->max, vr0->min) != 0)
1388 /* Return true if VR includes the value zero, false otherwise. FIXME,
1389 currently this will return false for an anti-range like ~[-4, 3].
1390 This will be wrong when the semantics of value_inside_range are
1391 modified (currently the users of this function expect these
1395 range_includes_zero_p (value_range_t *vr)
1399 gcc_assert (vr->type != VR_UNDEFINED
1400 && vr->type != VR_VARYING
1401 && !symbolic_range_p (vr));
1403 zero = build_int_cst (TREE_TYPE (vr->min), 0);
1404 return (value_inside_range (zero, vr) == 1);
1407 /* Return true if T, an SSA_NAME, is known to be nonnegative. Return
1408 false otherwise or if no value range information is available. */
1411 ssa_name_nonnegative_p (const_tree t)
1413 value_range_t *vr = get_value_range (t);
1415 if (INTEGRAL_TYPE_P (t)
1416 && TYPE_UNSIGNED (t))
1422 /* Testing for VR_ANTI_RANGE is not useful here as any anti-range
1423 which would return a useful value should be encoded as a VR_RANGE. */
1424 if (vr->type == VR_RANGE)
1426 int result = compare_values (vr->min, integer_zero_node);
1428 return (result == 0 || result == 1);
1433 /* If OP has a value range with a single constant value return that,
1434 otherwise return NULL_TREE. This returns OP itself if OP is a
1438 op_with_constant_singleton_value_range (tree op)
1442 if (is_gimple_min_invariant (op))
1445 if (TREE_CODE (op) != SSA_NAME)
1448 vr = get_value_range (op);
1449 if (vr->type == VR_RANGE
1450 && operand_equal_p (vr->min, vr->max, 0)
1451 && is_gimple_min_invariant (vr->min))
1458 /* Extract value range information from an ASSERT_EXPR EXPR and store
1462 extract_range_from_assert (value_range_t *vr_p, tree expr)
1464 tree var, cond, limit, min, max, type;
1465 value_range_t *var_vr, *limit_vr;
1466 enum tree_code cond_code;
1468 var = ASSERT_EXPR_VAR (expr);
1469 cond = ASSERT_EXPR_COND (expr);
1471 gcc_assert (COMPARISON_CLASS_P (cond));
1473 /* Find VAR in the ASSERT_EXPR conditional. */
1474 if (var == TREE_OPERAND (cond, 0)
1475 || TREE_CODE (TREE_OPERAND (cond, 0)) == PLUS_EXPR
1476 || TREE_CODE (TREE_OPERAND (cond, 0)) == NOP_EXPR)
1478 /* If the predicate is of the form VAR COMP LIMIT, then we just
1479 take LIMIT from the RHS and use the same comparison code. */
1480 cond_code = TREE_CODE (cond);
1481 limit = TREE_OPERAND (cond, 1);
1482 cond = TREE_OPERAND (cond, 0);
1486 /* If the predicate is of the form LIMIT COMP VAR, then we need
1487 to flip around the comparison code to create the proper range
1489 cond_code = swap_tree_comparison (TREE_CODE (cond));
1490 limit = TREE_OPERAND (cond, 0);
1491 cond = TREE_OPERAND (cond, 1);
1494 limit = avoid_overflow_infinity (limit);
1496 type = TREE_TYPE (limit);
1497 gcc_assert (limit != var);
1499 /* For pointer arithmetic, we only keep track of pointer equality
1501 if (POINTER_TYPE_P (type) && cond_code != NE_EXPR && cond_code != EQ_EXPR)
1503 set_value_range_to_varying (vr_p);
1507 /* If LIMIT is another SSA name and LIMIT has a range of its own,
1508 try to use LIMIT's range to avoid creating symbolic ranges
1510 limit_vr = (TREE_CODE (limit) == SSA_NAME) ? get_value_range (limit) : NULL;
1512 /* LIMIT's range is only interesting if it has any useful information. */
1514 && (limit_vr->type == VR_UNDEFINED
1515 || limit_vr->type == VR_VARYING
1516 || symbolic_range_p (limit_vr)))
1519 /* Initially, the new range has the same set of equivalences of
1520 VAR's range. This will be revised before returning the final
1521 value. Since assertions may be chained via mutually exclusive
1522 predicates, we will need to trim the set of equivalences before
1524 gcc_assert (vr_p->equiv == NULL);
1525 add_equivalence (&vr_p->equiv, var);
1527 /* Extract a new range based on the asserted comparison for VAR and
1528 LIMIT's value range. Notice that if LIMIT has an anti-range, we
1529 will only use it for equality comparisons (EQ_EXPR). For any
1530 other kind of assertion, we cannot derive a range from LIMIT's
1531 anti-range that can be used to describe the new range. For
1532 instance, ASSERT_EXPR <x_2, x_2 <= b_4>. If b_4 is ~[2, 10],
1533 then b_4 takes on the ranges [-INF, 1] and [11, +INF]. There is
1534 no single range for x_2 that could describe LE_EXPR, so we might
1535 as well build the range [b_4, +INF] for it.
1536 One special case we handle is extracting a range from a
1537 range test encoded as (unsigned)var + CST <= limit. */
1538 if (TREE_CODE (cond) == NOP_EXPR
1539 || TREE_CODE (cond) == PLUS_EXPR)
1541 if (TREE_CODE (cond) == PLUS_EXPR)
1543 min = fold_build1 (NEGATE_EXPR, TREE_TYPE (TREE_OPERAND (cond, 1)),
1544 TREE_OPERAND (cond, 1));
1545 max = int_const_binop (PLUS_EXPR, limit, min);
1546 cond = TREE_OPERAND (cond, 0);
1550 min = build_int_cst (TREE_TYPE (var), 0);
1554 /* Make sure to not set TREE_OVERFLOW on the final type
1555 conversion. We are willingly interpreting large positive
1556 unsigned values as negative singed values here. */
1557 min = force_fit_type_double (TREE_TYPE (var), tree_to_double_int (min),
1559 max = force_fit_type_double (TREE_TYPE (var), tree_to_double_int (max),
1562 /* We can transform a max, min range to an anti-range or
1563 vice-versa. Use set_and_canonicalize_value_range which does
1565 if (cond_code == LE_EXPR)
1566 set_and_canonicalize_value_range (vr_p, VR_RANGE,
1567 min, max, vr_p->equiv);
1568 else if (cond_code == GT_EXPR)
1569 set_and_canonicalize_value_range (vr_p, VR_ANTI_RANGE,
1570 min, max, vr_p->equiv);
1574 else if (cond_code == EQ_EXPR)
1576 enum value_range_type range_type;
1580 range_type = limit_vr->type;
1581 min = limit_vr->min;
1582 max = limit_vr->max;
1586 range_type = VR_RANGE;
1591 set_value_range (vr_p, range_type, min, max, vr_p->equiv);
1593 /* When asserting the equality VAR == LIMIT and LIMIT is another
1594 SSA name, the new range will also inherit the equivalence set
1596 if (TREE_CODE (limit) == SSA_NAME)
1597 add_equivalence (&vr_p->equiv, limit);
1599 else if (cond_code == NE_EXPR)
1601 /* As described above, when LIMIT's range is an anti-range and
1602 this assertion is an inequality (NE_EXPR), then we cannot
1603 derive anything from the anti-range. For instance, if
1604 LIMIT's range was ~[0, 0], the assertion 'VAR != LIMIT' does
1605 not imply that VAR's range is [0, 0]. So, in the case of
1606 anti-ranges, we just assert the inequality using LIMIT and
1609 If LIMIT_VR is a range, we can only use it to build a new
1610 anti-range if LIMIT_VR is a single-valued range. For
1611 instance, if LIMIT_VR is [0, 1], the predicate
1612 VAR != [0, 1] does not mean that VAR's range is ~[0, 1].
1613 Rather, it means that for value 0 VAR should be ~[0, 0]
1614 and for value 1, VAR should be ~[1, 1]. We cannot
1615 represent these ranges.
1617 The only situation in which we can build a valid
1618 anti-range is when LIMIT_VR is a single-valued range
1619 (i.e., LIMIT_VR->MIN == LIMIT_VR->MAX). In that case,
1620 build the anti-range ~[LIMIT_VR->MIN, LIMIT_VR->MAX]. */
1622 && limit_vr->type == VR_RANGE
1623 && compare_values (limit_vr->min, limit_vr->max) == 0)
1625 min = limit_vr->min;
1626 max = limit_vr->max;
1630 /* In any other case, we cannot use LIMIT's range to build a
1631 valid anti-range. */
1635 /* If MIN and MAX cover the whole range for their type, then
1636 just use the original LIMIT. */
1637 if (INTEGRAL_TYPE_P (type)
1638 && vrp_val_is_min (min)
1639 && vrp_val_is_max (max))
1642 set_value_range (vr_p, VR_ANTI_RANGE, min, max, vr_p->equiv);
1644 else if (cond_code == LE_EXPR || cond_code == LT_EXPR)
1646 min = TYPE_MIN_VALUE (type);
1648 if (limit_vr == NULL || limit_vr->type == VR_ANTI_RANGE)
1652 /* If LIMIT_VR is of the form [N1, N2], we need to build the
1653 range [MIN, N2] for LE_EXPR and [MIN, N2 - 1] for
1655 max = limit_vr->max;
1658 /* If the maximum value forces us to be out of bounds, simply punt.
1659 It would be pointless to try and do anything more since this
1660 all should be optimized away above us. */
1661 if ((cond_code == LT_EXPR
1662 && compare_values (max, min) == 0)
1663 || (CONSTANT_CLASS_P (max) && TREE_OVERFLOW (max)))
1664 set_value_range_to_varying (vr_p);
1667 /* For LT_EXPR, we create the range [MIN, MAX - 1]. */
1668 if (cond_code == LT_EXPR)
1670 tree one = build_int_cst (type, 1);
1671 max = fold_build2 (MINUS_EXPR, type, max, one);
1673 TREE_NO_WARNING (max) = 1;
1676 set_value_range (vr_p, VR_RANGE, min, max, vr_p->equiv);
1679 else if (cond_code == GE_EXPR || cond_code == GT_EXPR)
1681 max = TYPE_MAX_VALUE (type);
1683 if (limit_vr == NULL || limit_vr->type == VR_ANTI_RANGE)
1687 /* If LIMIT_VR is of the form [N1, N2], we need to build the
1688 range [N1, MAX] for GE_EXPR and [N1 + 1, MAX] for
1690 min = limit_vr->min;
1693 /* If the minimum value forces us to be out of bounds, simply punt.
1694 It would be pointless to try and do anything more since this
1695 all should be optimized away above us. */
1696 if ((cond_code == GT_EXPR
1697 && compare_values (min, max) == 0)
1698 || (CONSTANT_CLASS_P (min) && TREE_OVERFLOW (min)))
1699 set_value_range_to_varying (vr_p);
1702 /* For GT_EXPR, we create the range [MIN + 1, MAX]. */
1703 if (cond_code == GT_EXPR)
1705 tree one = build_int_cst (type, 1);
1706 min = fold_build2 (PLUS_EXPR, type, min, one);
1708 TREE_NO_WARNING (min) = 1;
1711 set_value_range (vr_p, VR_RANGE, min, max, vr_p->equiv);
1717 /* If VAR already had a known range, it may happen that the new
1718 range we have computed and VAR's range are not compatible. For
1722 p_6 = ASSERT_EXPR <p_5, p_5 == NULL>;
1724 p_8 = ASSERT_EXPR <p_6, p_6 != NULL>;
1726 While the above comes from a faulty program, it will cause an ICE
1727 later because p_8 and p_6 will have incompatible ranges and at
1728 the same time will be considered equivalent. A similar situation
1732 i_6 = ASSERT_EXPR <i_5, i_5 > 10>;
1734 i_7 = ASSERT_EXPR <i_6, i_6 < 5>;
1736 Again i_6 and i_7 will have incompatible ranges. It would be
1737 pointless to try and do anything with i_7's range because
1738 anything dominated by 'if (i_5 < 5)' will be optimized away.
1739 Note, due to the wa in which simulation proceeds, the statement
1740 i_7 = ASSERT_EXPR <...> we would never be visited because the
1741 conditional 'if (i_5 < 5)' always evaluates to false. However,
1742 this extra check does not hurt and may protect against future
1743 changes to VRP that may get into a situation similar to the
1744 NULL pointer dereference example.
1746 Note that these compatibility tests are only needed when dealing
1747 with ranges or a mix of range and anti-range. If VAR_VR and VR_P
1748 are both anti-ranges, they will always be compatible, because two
1749 anti-ranges will always have a non-empty intersection. */
1751 var_vr = get_value_range (var);
1753 /* We may need to make adjustments when VR_P and VAR_VR are numeric
1754 ranges or anti-ranges. */
1755 if (vr_p->type == VR_VARYING
1756 || vr_p->type == VR_UNDEFINED
1757 || var_vr->type == VR_VARYING
1758 || var_vr->type == VR_UNDEFINED
1759 || symbolic_range_p (vr_p)
1760 || symbolic_range_p (var_vr))
1763 if (var_vr->type == VR_RANGE && vr_p->type == VR_RANGE)
1765 /* If the two ranges have a non-empty intersection, we can
1766 refine the resulting range. Since the assert expression
1767 creates an equivalency and at the same time it asserts a
1768 predicate, we can take the intersection of the two ranges to
1769 get better precision. */
1770 if (value_ranges_intersect_p (var_vr, vr_p))
1772 /* Use the larger of the two minimums. */
1773 if (compare_values (vr_p->min, var_vr->min) == -1)
1778 /* Use the smaller of the two maximums. */
1779 if (compare_values (vr_p->max, var_vr->max) == 1)
1784 set_value_range (vr_p, vr_p->type, min, max, vr_p->equiv);
1788 /* The two ranges do not intersect, set the new range to
1789 VARYING, because we will not be able to do anything
1790 meaningful with it. */
1791 set_value_range_to_varying (vr_p);
1794 else if ((var_vr->type == VR_RANGE && vr_p->type == VR_ANTI_RANGE)
1795 || (var_vr->type == VR_ANTI_RANGE && vr_p->type == VR_RANGE))
1797 /* A range and an anti-range will cancel each other only if
1798 their ends are the same. For instance, in the example above,
1799 p_8's range ~[0, 0] and p_6's range [0, 0] are incompatible,
1800 so VR_P should be set to VR_VARYING. */
1801 if (compare_values (var_vr->min, vr_p->min) == 0
1802 && compare_values (var_vr->max, vr_p->max) == 0)
1803 set_value_range_to_varying (vr_p);
1806 tree min, max, anti_min, anti_max, real_min, real_max;
1809 /* We want to compute the logical AND of the two ranges;
1810 there are three cases to consider.
1813 1. The VR_ANTI_RANGE range is completely within the
1814 VR_RANGE and the endpoints of the ranges are
1815 different. In that case the resulting range
1816 should be whichever range is more precise.
1817 Typically that will be the VR_RANGE.
1819 2. The VR_ANTI_RANGE is completely disjoint from
1820 the VR_RANGE. In this case the resulting range
1821 should be the VR_RANGE.
1823 3. There is some overlap between the VR_ANTI_RANGE
1826 3a. If the high limit of the VR_ANTI_RANGE resides
1827 within the VR_RANGE, then the result is a new
1828 VR_RANGE starting at the high limit of the
1829 VR_ANTI_RANGE + 1 and extending to the
1830 high limit of the original VR_RANGE.
1832 3b. If the low limit of the VR_ANTI_RANGE resides
1833 within the VR_RANGE, then the result is a new
1834 VR_RANGE starting at the low limit of the original
1835 VR_RANGE and extending to the low limit of the
1836 VR_ANTI_RANGE - 1. */
1837 if (vr_p->type == VR_ANTI_RANGE)
1839 anti_min = vr_p->min;
1840 anti_max = vr_p->max;
1841 real_min = var_vr->min;
1842 real_max = var_vr->max;
1846 anti_min = var_vr->min;
1847 anti_max = var_vr->max;
1848 real_min = vr_p->min;
1849 real_max = vr_p->max;
1853 /* Case 1, VR_ANTI_RANGE completely within VR_RANGE,
1854 not including any endpoints. */
1855 if (compare_values (anti_max, real_max) == -1
1856 && compare_values (anti_min, real_min) == 1)
1858 /* If the range is covering the whole valid range of
1859 the type keep the anti-range. */
1860 if (!vrp_val_is_min (real_min)
1861 || !vrp_val_is_max (real_max))
1862 set_value_range (vr_p, VR_RANGE, real_min,
1863 real_max, vr_p->equiv);
1865 /* Case 2, VR_ANTI_RANGE completely disjoint from
1867 else if (compare_values (anti_min, real_max) == 1
1868 || compare_values (anti_max, real_min) == -1)
1870 set_value_range (vr_p, VR_RANGE, real_min,
1871 real_max, vr_p->equiv);
1873 /* Case 3a, the anti-range extends into the low
1874 part of the real range. Thus creating a new
1875 low for the real range. */
1876 else if (((cmp = compare_values (anti_max, real_min)) == 1
1878 && compare_values (anti_max, real_max) == -1)
1880 gcc_assert (!is_positive_overflow_infinity (anti_max));
1881 if (needs_overflow_infinity (TREE_TYPE (anti_max))
1882 && vrp_val_is_max (anti_max))
1884 if (!supports_overflow_infinity (TREE_TYPE (var_vr->min)))
1886 set_value_range_to_varying (vr_p);
1889 min = positive_overflow_infinity (TREE_TYPE (var_vr->min));
1891 else if (!POINTER_TYPE_P (TREE_TYPE (var_vr->min)))
1892 min = fold_build2 (PLUS_EXPR, TREE_TYPE (var_vr->min),
1894 build_int_cst (TREE_TYPE (var_vr->min), 1));
1896 min = fold_build_pointer_plus_hwi (anti_max, 1);
1898 set_value_range (vr_p, VR_RANGE, min, max, vr_p->equiv);
1900 /* Case 3b, the anti-range extends into the high
1901 part of the real range. Thus creating a new
1902 higher for the real range. */
1903 else if (compare_values (anti_min, real_min) == 1
1904 && ((cmp = compare_values (anti_min, real_max)) == -1
1907 gcc_assert (!is_negative_overflow_infinity (anti_min));
1908 if (needs_overflow_infinity (TREE_TYPE (anti_min))
1909 && vrp_val_is_min (anti_min))
1911 if (!supports_overflow_infinity (TREE_TYPE (var_vr->min)))
1913 set_value_range_to_varying (vr_p);
1916 max = negative_overflow_infinity (TREE_TYPE (var_vr->min));
1918 else if (!POINTER_TYPE_P (TREE_TYPE (var_vr->min)))
1919 max = fold_build2 (MINUS_EXPR, TREE_TYPE (var_vr->min),
1921 build_int_cst (TREE_TYPE (var_vr->min), 1));
1923 max = fold_build_pointer_plus_hwi (anti_min, -1);
1925 set_value_range (vr_p, VR_RANGE, min, max, vr_p->equiv);
1932 /* Extract range information from SSA name VAR and store it in VR. If
1933 VAR has an interesting range, use it. Otherwise, create the
1934 range [VAR, VAR] and return it. This is useful in situations where
1935 we may have conditionals testing values of VARYING names. For
1942 Even if y_5 is deemed VARYING, we can determine that x_3 > y_5 is
1946 extract_range_from_ssa_name (value_range_t *vr, tree var)
1948 value_range_t *var_vr = get_value_range (var);
1950 if (var_vr->type != VR_UNDEFINED && var_vr->type != VR_VARYING)
1951 copy_value_range (vr, var_vr);
1953 set_value_range (vr, VR_RANGE, var, var, NULL);
1955 add_equivalence (&vr->equiv, var);
1959 /* Wrapper around int_const_binop. If the operation overflows and we
1960 are not using wrapping arithmetic, then adjust the result to be
1961 -INF or +INF depending on CODE, VAL1 and VAL2. This can return
1962 NULL_TREE if we need to use an overflow infinity representation but
1963 the type does not support it. */
1966 vrp_int_const_binop (enum tree_code code, tree val1, tree val2)
1970 res = int_const_binop (code, val1, val2);
1972 /* If we are using unsigned arithmetic, operate symbolically
1973 on -INF and +INF as int_const_binop only handles signed overflow. */
1974 if (TYPE_UNSIGNED (TREE_TYPE (val1)))
1976 int checkz = compare_values (res, val1);
1977 bool overflow = false;
1979 /* Ensure that res = val1 [+*] val2 >= val1
1980 or that res = val1 - val2 <= val1. */
1981 if ((code == PLUS_EXPR
1982 && !(checkz == 1 || checkz == 0))
1983 || (code == MINUS_EXPR
1984 && !(checkz == 0 || checkz == -1)))
1988 /* Checking for multiplication overflow is done by dividing the
1989 output of the multiplication by the first input of the
1990 multiplication. If the result of that division operation is
1991 not equal to the second input of the multiplication, then the
1992 multiplication overflowed. */
1993 else if (code == MULT_EXPR && !integer_zerop (val1))
1995 tree tmp = int_const_binop (TRUNC_DIV_EXPR,
1998 int check = compare_values (tmp, val2);
2006 res = copy_node (res);
2007 TREE_OVERFLOW (res) = 1;
2011 else if (TYPE_OVERFLOW_WRAPS (TREE_TYPE (val1)))
2012 /* If the singed operation wraps then int_const_binop has done
2013 everything we want. */
2015 else if ((TREE_OVERFLOW (res)
2016 && !TREE_OVERFLOW (val1)
2017 && !TREE_OVERFLOW (val2))
2018 || is_overflow_infinity (val1)
2019 || is_overflow_infinity (val2))
2021 /* If the operation overflowed but neither VAL1 nor VAL2 are
2022 overflown, return -INF or +INF depending on the operation
2023 and the combination of signs of the operands. */
2024 int sgn1 = tree_int_cst_sgn (val1);
2025 int sgn2 = tree_int_cst_sgn (val2);
2027 if (needs_overflow_infinity (TREE_TYPE (res))
2028 && !supports_overflow_infinity (TREE_TYPE (res)))
2031 /* We have to punt on adding infinities of different signs,
2032 since we can't tell what the sign of the result should be.
2033 Likewise for subtracting infinities of the same sign. */
2034 if (((code == PLUS_EXPR && sgn1 != sgn2)
2035 || (code == MINUS_EXPR && sgn1 == sgn2))
2036 && is_overflow_infinity (val1)
2037 && is_overflow_infinity (val2))
2040 /* Don't try to handle division or shifting of infinities. */
2041 if ((code == TRUNC_DIV_EXPR
2042 || code == FLOOR_DIV_EXPR
2043 || code == CEIL_DIV_EXPR
2044 || code == EXACT_DIV_EXPR
2045 || code == ROUND_DIV_EXPR
2046 || code == RSHIFT_EXPR)
2047 && (is_overflow_infinity (val1)
2048 || is_overflow_infinity (val2)))
2051 /* Notice that we only need to handle the restricted set of
2052 operations handled by extract_range_from_binary_expr.
2053 Among them, only multiplication, addition and subtraction
2054 can yield overflow without overflown operands because we
2055 are working with integral types only... except in the
2056 case VAL1 = -INF and VAL2 = -1 which overflows to +INF
2057 for division too. */
2059 /* For multiplication, the sign of the overflow is given
2060 by the comparison of the signs of the operands. */
2061 if ((code == MULT_EXPR && sgn1 == sgn2)
2062 /* For addition, the operands must be of the same sign
2063 to yield an overflow. Its sign is therefore that
2064 of one of the operands, for example the first. For
2065 infinite operands X + -INF is negative, not positive. */
2066 || (code == PLUS_EXPR
2068 ? !is_negative_overflow_infinity (val2)
2069 : is_positive_overflow_infinity (val2)))
2070 /* For subtraction, non-infinite operands must be of
2071 different signs to yield an overflow. Its sign is
2072 therefore that of the first operand or the opposite of
2073 that of the second operand. A first operand of 0 counts
2074 as positive here, for the corner case 0 - (-INF), which
2075 overflows, but must yield +INF. For infinite operands 0
2076 - INF is negative, not positive. */
2077 || (code == MINUS_EXPR
2079 ? !is_positive_overflow_infinity (val2)
2080 : is_negative_overflow_infinity (val2)))
2081 /* We only get in here with positive shift count, so the
2082 overflow direction is the same as the sign of val1.
2083 Actually rshift does not overflow at all, but we only
2084 handle the case of shifting overflowed -INF and +INF. */
2085 || (code == RSHIFT_EXPR
2087 /* For division, the only case is -INF / -1 = +INF. */
2088 || code == TRUNC_DIV_EXPR
2089 || code == FLOOR_DIV_EXPR
2090 || code == CEIL_DIV_EXPR
2091 || code == EXACT_DIV_EXPR
2092 || code == ROUND_DIV_EXPR)
2093 return (needs_overflow_infinity (TREE_TYPE (res))
2094 ? positive_overflow_infinity (TREE_TYPE (res))
2095 : TYPE_MAX_VALUE (TREE_TYPE (res)));
2097 return (needs_overflow_infinity (TREE_TYPE (res))
2098 ? negative_overflow_infinity (TREE_TYPE (res))
2099 : TYPE_MIN_VALUE (TREE_TYPE (res)));
2106 /* For range VR compute two double_int bitmasks. In *MAY_BE_NONZERO
2107 bitmask if some bit is unset, it means for all numbers in the range
2108 the bit is 0, otherwise it might be 0 or 1. In *MUST_BE_NONZERO
2109 bitmask if some bit is set, it means for all numbers in the range
2110 the bit is 1, otherwise it might be 0 or 1. */
2113 zero_nonzero_bits_from_vr (value_range_t *vr, double_int *may_be_nonzero,
2114 double_int *must_be_nonzero)
2116 if (range_int_cst_p (vr))
2118 if (range_int_cst_singleton_p (vr))
2120 *may_be_nonzero = tree_to_double_int (vr->min);
2121 *must_be_nonzero = *may_be_nonzero;
2124 if (tree_int_cst_sgn (vr->min) >= 0)
2126 double_int dmin = tree_to_double_int (vr->min);
2127 double_int dmax = tree_to_double_int (vr->max);
2128 double_int xor_mask = double_int_xor (dmin, dmax);
2129 *may_be_nonzero = double_int_ior (dmin, dmax);
2130 *must_be_nonzero = double_int_and (dmin, dmax);
2131 if (xor_mask.high != 0)
2133 unsigned HOST_WIDE_INT mask
2134 = ((unsigned HOST_WIDE_INT) 1
2135 << floor_log2 (xor_mask.high)) - 1;
2136 may_be_nonzero->low = ALL_ONES;
2137 may_be_nonzero->high |= mask;
2138 must_be_nonzero->low = 0;
2139 must_be_nonzero->high &= ~mask;
2141 else if (xor_mask.low != 0)
2143 unsigned HOST_WIDE_INT mask
2144 = ((unsigned HOST_WIDE_INT) 1
2145 << floor_log2 (xor_mask.low)) - 1;
2146 may_be_nonzero->low |= mask;
2147 must_be_nonzero->low &= ~mask;
2152 may_be_nonzero->low = ALL_ONES;
2153 may_be_nonzero->high = ALL_ONES;
2154 must_be_nonzero->low = 0;
2155 must_be_nonzero->high = 0;
2160 /* Extract range information from a binary expression EXPR based on
2161 the ranges of each of its operands and the expression code. */
2164 extract_range_from_binary_expr (value_range_t *vr,
2165 enum tree_code code,
2166 tree expr_type, tree op0, tree op1)
2168 enum value_range_type type;
2171 value_range_t vr0 = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
2172 value_range_t vr1 = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
2174 /* Not all binary expressions can be applied to ranges in a
2175 meaningful way. Handle only arithmetic operations. */
2176 if (code != PLUS_EXPR
2177 && code != MINUS_EXPR
2178 && code != POINTER_PLUS_EXPR
2179 && code != MULT_EXPR
2180 && code != TRUNC_DIV_EXPR
2181 && code != FLOOR_DIV_EXPR
2182 && code != CEIL_DIV_EXPR
2183 && code != EXACT_DIV_EXPR
2184 && code != ROUND_DIV_EXPR
2185 && code != TRUNC_MOD_EXPR
2186 && code != RSHIFT_EXPR
2189 && code != BIT_AND_EXPR
2190 && code != BIT_IOR_EXPR)
2192 /* We can still do constant propagation here. */
2193 tree const_op0 = op_with_constant_singleton_value_range (op0);
2194 tree const_op1 = op_with_constant_singleton_value_range (op1);
2195 if (const_op0 || const_op1)
2197 tree tem = fold_binary (code, expr_type,
2198 const_op0 ? const_op0 : op0,
2199 const_op1 ? const_op1 : op1);
2201 && is_gimple_min_invariant (tem)
2202 && !is_overflow_infinity (tem))
2204 set_value_range (vr, VR_RANGE, tem, tem, NULL);
2208 set_value_range_to_varying (vr);
2212 /* Get value ranges for each operand. For constant operands, create
2213 a new value range with the operand to simplify processing. */
2214 if (TREE_CODE (op0) == SSA_NAME)
2215 vr0 = *(get_value_range (op0));
2216 else if (is_gimple_min_invariant (op0))
2217 set_value_range_to_value (&vr0, op0, NULL);
2219 set_value_range_to_varying (&vr0);
2221 if (TREE_CODE (op1) == SSA_NAME)
2222 vr1 = *(get_value_range (op1));
2223 else if (is_gimple_min_invariant (op1))
2224 set_value_range_to_value (&vr1, op1, NULL);
2226 set_value_range_to_varying (&vr1);
2228 /* If either range is UNDEFINED, so is the result. */
2229 if (vr0.type == VR_UNDEFINED || vr1.type == VR_UNDEFINED)
2231 set_value_range_to_undefined (vr);
2235 /* The type of the resulting value range defaults to VR0.TYPE. */
2238 /* Refuse to operate on VARYING ranges, ranges of different kinds
2239 and symbolic ranges. As an exception, we allow BIT_AND_EXPR
2240 because we may be able to derive a useful range even if one of
2241 the operands is VR_VARYING or symbolic range. Similarly for
2242 divisions. TODO, we may be able to derive anti-ranges in
2244 if (code != BIT_AND_EXPR
2245 && code != BIT_IOR_EXPR
2246 && code != TRUNC_DIV_EXPR
2247 && code != FLOOR_DIV_EXPR
2248 && code != CEIL_DIV_EXPR
2249 && code != EXACT_DIV_EXPR
2250 && code != ROUND_DIV_EXPR
2251 && code != TRUNC_MOD_EXPR
2252 && (vr0.type == VR_VARYING
2253 || vr1.type == VR_VARYING
2254 || vr0.type != vr1.type
2255 || symbolic_range_p (&vr0)
2256 || symbolic_range_p (&vr1)))
2258 set_value_range_to_varying (vr);
2262 /* Now evaluate the expression to determine the new range. */
2263 if (POINTER_TYPE_P (expr_type)
2264 || POINTER_TYPE_P (TREE_TYPE (op0))
2265 || POINTER_TYPE_P (TREE_TYPE (op1)))
2267 if (code == BIT_IOR_EXPR)
2269 set_value_range_to_varying (vr);
2272 else if (code == MIN_EXPR || code == MAX_EXPR)
2274 /* For MIN/MAX expressions with pointers, we only care about
2275 nullness, if both are non null, then the result is nonnull.
2276 If both are null, then the result is null. Otherwise they
2278 if (range_is_nonnull (&vr0) && range_is_nonnull (&vr1))
2279 set_value_range_to_nonnull (vr, expr_type);
2280 else if (range_is_null (&vr0) && range_is_null (&vr1))
2281 set_value_range_to_null (vr, expr_type);
2283 set_value_range_to_varying (vr);
2287 if (code == POINTER_PLUS_EXPR)
2289 /* For pointer types, we are really only interested in asserting
2290 whether the expression evaluates to non-NULL. */
2291 if (range_is_nonnull (&vr0) || range_is_nonnull (&vr1))
2292 set_value_range_to_nonnull (vr, expr_type);
2293 else if (range_is_null (&vr0) && range_is_null (&vr1))
2294 set_value_range_to_null (vr, expr_type);
2296 set_value_range_to_varying (vr);
2298 else if (code == BIT_AND_EXPR)
2300 /* For pointer types, we are really only interested in asserting
2301 whether the expression evaluates to non-NULL. */
2302 if (range_is_nonnull (&vr0) && range_is_nonnull (&vr1))
2303 set_value_range_to_nonnull (vr, expr_type);
2304 else if (range_is_null (&vr0) || range_is_null (&vr1))
2305 set_value_range_to_null (vr, expr_type);
2307 set_value_range_to_varying (vr);
2315 /* For integer ranges, apply the operation to each end of the
2316 range and see what we end up with. */
2317 if (code == PLUS_EXPR
2319 || code == MAX_EXPR)
2321 /* If we have a PLUS_EXPR with two VR_ANTI_RANGEs, drop to
2322 VR_VARYING. It would take more effort to compute a precise
2323 range for such a case. For example, if we have op0 == 1 and
2324 op1 == -1 with their ranges both being ~[0,0], we would have
2325 op0 + op1 == 0, so we cannot claim that the sum is in ~[0,0].
2326 Note that we are guaranteed to have vr0.type == vr1.type at
2328 if (vr0.type == VR_ANTI_RANGE)
2330 if (code == PLUS_EXPR)
2332 set_value_range_to_varying (vr);
2335 /* For MIN_EXPR and MAX_EXPR with two VR_ANTI_RANGEs,
2336 the resulting VR_ANTI_RANGE is the same - intersection
2337 of the two ranges. */
2338 min = vrp_int_const_binop (MAX_EXPR, vr0.min, vr1.min);
2339 max = vrp_int_const_binop (MIN_EXPR, vr0.max, vr1.max);
2343 /* For operations that make the resulting range directly
2344 proportional to the original ranges, apply the operation to
2345 the same end of each range. */
2346 min = vrp_int_const_binop (code, vr0.min, vr1.min);
2347 max = vrp_int_const_binop (code, vr0.max, vr1.max);
2350 /* If both additions overflowed the range kind is still correct.
2351 This happens regularly with subtracting something in unsigned
2353 ??? See PR30318 for all the cases we do not handle. */
2354 if (code == PLUS_EXPR
2355 && (TREE_OVERFLOW (min) && !is_overflow_infinity (min))
2356 && (TREE_OVERFLOW (max) && !is_overflow_infinity (max)))
2358 min = build_int_cst_wide (TREE_TYPE (min),
2359 TREE_INT_CST_LOW (min),
2360 TREE_INT_CST_HIGH (min));
2361 max = build_int_cst_wide (TREE_TYPE (max),
2362 TREE_INT_CST_LOW (max),
2363 TREE_INT_CST_HIGH (max));
2366 else if (code == MULT_EXPR
2367 || code == TRUNC_DIV_EXPR
2368 || code == FLOOR_DIV_EXPR
2369 || code == CEIL_DIV_EXPR
2370 || code == EXACT_DIV_EXPR
2371 || code == ROUND_DIV_EXPR
2372 || code == RSHIFT_EXPR)
2378 /* If we have an unsigned MULT_EXPR with two VR_ANTI_RANGEs,
2379 drop to VR_VARYING. It would take more effort to compute a
2380 precise range for such a case. For example, if we have
2381 op0 == 65536 and op1 == 65536 with their ranges both being
2382 ~[0,0] on a 32-bit machine, we would have op0 * op1 == 0, so
2383 we cannot claim that the product is in ~[0,0]. Note that we
2384 are guaranteed to have vr0.type == vr1.type at this
2386 if (code == MULT_EXPR
2387 && vr0.type == VR_ANTI_RANGE
2388 && !TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (op0)))
2390 set_value_range_to_varying (vr);
2394 /* If we have a RSHIFT_EXPR with any shift values outside [0..prec-1],
2395 then drop to VR_VARYING. Outside of this range we get undefined
2396 behavior from the shift operation. We cannot even trust
2397 SHIFT_COUNT_TRUNCATED at this stage, because that applies to rtl
2398 shifts, and the operation at the tree level may be widened. */
2399 if (code == RSHIFT_EXPR)
2401 if (vr1.type == VR_ANTI_RANGE
2402 || !vrp_expr_computes_nonnegative (op1, &sop)
2404 (build_int_cst (TREE_TYPE (vr1.max),
2405 TYPE_PRECISION (expr_type) - 1),
2408 set_value_range_to_varying (vr);
2413 else if ((code == TRUNC_DIV_EXPR
2414 || code == FLOOR_DIV_EXPR
2415 || code == CEIL_DIV_EXPR
2416 || code == EXACT_DIV_EXPR
2417 || code == ROUND_DIV_EXPR)
2418 && (vr0.type != VR_RANGE || symbolic_range_p (&vr0)))
2420 /* For division, if op1 has VR_RANGE but op0 does not, something
2421 can be deduced just from that range. Say [min, max] / [4, max]
2422 gives [min / 4, max / 4] range. */
2423 if (vr1.type == VR_RANGE
2424 && !symbolic_range_p (&vr1)
2425 && !range_includes_zero_p (&vr1))
2427 vr0.type = type = VR_RANGE;
2428 vr0.min = vrp_val_min (TREE_TYPE (op0));
2429 vr0.max = vrp_val_max (TREE_TYPE (op1));
2433 set_value_range_to_varying (vr);
2438 /* For divisions, if flag_non_call_exceptions is true, we must
2439 not eliminate a division by zero. */
2440 if ((code == TRUNC_DIV_EXPR
2441 || code == FLOOR_DIV_EXPR
2442 || code == CEIL_DIV_EXPR
2443 || code == EXACT_DIV_EXPR
2444 || code == ROUND_DIV_EXPR)
2445 && cfun->can_throw_non_call_exceptions
2446 && (vr1.type != VR_RANGE
2447 || symbolic_range_p (&vr1)
2448 || range_includes_zero_p (&vr1)))
2450 set_value_range_to_varying (vr);
2454 /* For divisions, if op0 is VR_RANGE, we can deduce a range
2455 even if op1 is VR_VARYING, VR_ANTI_RANGE, symbolic or can
2457 if ((code == TRUNC_DIV_EXPR
2458 || code == FLOOR_DIV_EXPR
2459 || code == CEIL_DIV_EXPR
2460 || code == EXACT_DIV_EXPR
2461 || code == ROUND_DIV_EXPR)
2462 && vr0.type == VR_RANGE
2463 && (vr1.type != VR_RANGE
2464 || symbolic_range_p (&vr1)
2465 || range_includes_zero_p (&vr1)))
2467 tree zero = build_int_cst (TREE_TYPE (vr0.min), 0);
2473 if (vrp_expr_computes_nonnegative (op1, &sop) && !sop)
2475 /* For unsigned division or when divisor is known
2476 to be non-negative, the range has to cover
2477 all numbers from 0 to max for positive max
2478 and all numbers from min to 0 for negative min. */
2479 cmp = compare_values (vr0.max, zero);
2482 else if (cmp == 0 || cmp == 1)
2486 cmp = compare_values (vr0.min, zero);
2489 else if (cmp == 0 || cmp == -1)
2496 /* Otherwise the range is -max .. max or min .. -min
2497 depending on which bound is bigger in absolute value,
2498 as the division can change the sign. */
2499 abs_extent_range (vr, vr0.min, vr0.max);
2502 if (type == VR_VARYING)
2504 set_value_range_to_varying (vr);
2509 /* Multiplications and divisions are a bit tricky to handle,
2510 depending on the mix of signs we have in the two ranges, we
2511 need to operate on different values to get the minimum and
2512 maximum values for the new range. One approach is to figure
2513 out all the variations of range combinations and do the
2516 However, this involves several calls to compare_values and it
2517 is pretty convoluted. It's simpler to do the 4 operations
2518 (MIN0 OP MIN1, MIN0 OP MAX1, MAX0 OP MIN1 and MAX0 OP MAX0 OP
2519 MAX1) and then figure the smallest and largest values to form
2523 gcc_assert ((vr0.type == VR_RANGE
2524 || (code == MULT_EXPR && vr0.type == VR_ANTI_RANGE))
2525 && vr0.type == vr1.type);
2527 /* Compute the 4 cross operations. */
2529 val[0] = vrp_int_const_binop (code, vr0.min, vr1.min);
2530 if (val[0] == NULL_TREE)
2533 if (vr1.max == vr1.min)
2537 val[1] = vrp_int_const_binop (code, vr0.min, vr1.max);
2538 if (val[1] == NULL_TREE)
2542 if (vr0.max == vr0.min)
2546 val[2] = vrp_int_const_binop (code, vr0.max, vr1.min);
2547 if (val[2] == NULL_TREE)
2551 if (vr0.min == vr0.max || vr1.min == vr1.max)
2555 val[3] = vrp_int_const_binop (code, vr0.max, vr1.max);
2556 if (val[3] == NULL_TREE)
2562 set_value_range_to_varying (vr);
2566 /* Set MIN to the minimum of VAL[i] and MAX to the maximum
2570 for (i = 1; i < 4; i++)
2572 if (!is_gimple_min_invariant (min)
2573 || (TREE_OVERFLOW (min) && !is_overflow_infinity (min))
2574 || !is_gimple_min_invariant (max)
2575 || (TREE_OVERFLOW (max) && !is_overflow_infinity (max)))
2580 if (!is_gimple_min_invariant (val[i])
2581 || (TREE_OVERFLOW (val[i])
2582 && !is_overflow_infinity (val[i])))
2584 /* If we found an overflowed value, set MIN and MAX
2585 to it so that we set the resulting range to
2591 if (compare_values (val[i], min) == -1)
2594 if (compare_values (val[i], max) == 1)
2600 else if (code == TRUNC_MOD_EXPR)
2603 if (vr1.type != VR_RANGE
2604 || symbolic_range_p (&vr1)
2605 || range_includes_zero_p (&vr1)
2606 || vrp_val_is_min (vr1.min))
2608 set_value_range_to_varying (vr);
2612 /* Compute MAX <|vr1.min|, |vr1.max|> - 1. */
2613 max = fold_unary_to_constant (ABS_EXPR, TREE_TYPE (vr1.min), vr1.min);
2614 if (tree_int_cst_lt (max, vr1.max))
2616 max = int_const_binop (MINUS_EXPR, max, integer_one_node);
2617 /* If the dividend is non-negative the modulus will be
2618 non-negative as well. */
2619 if (TYPE_UNSIGNED (TREE_TYPE (max))
2620 || (vrp_expr_computes_nonnegative (op0, &sop) && !sop))
2621 min = build_int_cst (TREE_TYPE (max), 0);
2623 min = fold_unary_to_constant (NEGATE_EXPR, TREE_TYPE (max), max);
2625 else if (code == MINUS_EXPR)
2627 /* If we have a MINUS_EXPR with two VR_ANTI_RANGEs, drop to
2628 VR_VARYING. It would take more effort to compute a precise
2629 range for such a case. For example, if we have op0 == 1 and
2630 op1 == 1 with their ranges both being ~[0,0], we would have
2631 op0 - op1 == 0, so we cannot claim that the difference is in
2632 ~[0,0]. Note that we are guaranteed to have
2633 vr0.type == vr1.type at this point. */
2634 if (vr0.type == VR_ANTI_RANGE)
2636 set_value_range_to_varying (vr);
2640 /* For MINUS_EXPR, apply the operation to the opposite ends of
2642 min = vrp_int_const_binop (code, vr0.min, vr1.max);
2643 max = vrp_int_const_binop (code, vr0.max, vr1.min);
2645 else if (code == BIT_AND_EXPR || code == BIT_IOR_EXPR)
2647 bool vr0_int_cst_singleton_p, vr1_int_cst_singleton_p;
2648 bool int_cst_range0, int_cst_range1;
2649 double_int may_be_nonzero0, may_be_nonzero1;
2650 double_int must_be_nonzero0, must_be_nonzero1;
2651 value_range_t *non_singleton_vr;
2654 vr0_int_cst_singleton_p = range_int_cst_singleton_p (&vr0);
2655 vr1_int_cst_singleton_p = range_int_cst_singleton_p (&vr1);
2656 int_cst_range0 = zero_nonzero_bits_from_vr (&vr0, &may_be_nonzero0,
2658 int_cst_range1 = zero_nonzero_bits_from_vr (&vr1, &may_be_nonzero1,
2661 singleton_val = (vr0_int_cst_singleton_p ? vr0.min : vr1.min);
2662 non_singleton_vr = (vr0_int_cst_singleton_p ? &vr1 : &vr0);
2665 if (vr0_int_cst_singleton_p && vr1_int_cst_singleton_p)
2666 min = max = int_const_binop (code, vr0.max, vr1.max);
2667 else if ((vr0_int_cst_singleton_p || vr1_int_cst_singleton_p)
2668 && (integer_zerop (singleton_val)
2669 || integer_all_onesp (singleton_val)))
2671 /* If one of the operands is zero for and-case, we know that
2672 * the whole expression evaluates zero.
2673 If one of the operands has all bits set to one for
2674 or-case, we know that the whole expression evaluates
2676 min = max = singleton_val;
2677 if ((code == BIT_IOR_EXPR
2678 && integer_zerop (singleton_val))
2679 || (code == BIT_AND_EXPR
2680 && integer_all_onesp (singleton_val)))
2681 /* If one of the operands has all bits set to one, we know
2682 that the whole expression evaluates to the other one for
2684 If one of the operands is zero, we know that the whole
2685 expression evaluates to the other one for the or-case. */
2687 type = non_singleton_vr->type;
2688 min = non_singleton_vr->min;
2689 max = non_singleton_vr->max;
2691 set_value_range (vr, type, min, max, NULL);
2694 else if (!int_cst_range0 && !int_cst_range1)
2696 set_value_range_to_varying (vr);
2699 else if (code == BIT_AND_EXPR)
2701 min = double_int_to_tree (expr_type,
2702 double_int_and (must_be_nonzero0,
2704 max = double_int_to_tree (expr_type,
2705 double_int_and (may_be_nonzero0,
2707 if (TREE_OVERFLOW (min) || tree_int_cst_sgn (min) < 0)
2709 if (TREE_OVERFLOW (max) || tree_int_cst_sgn (max) < 0)
2711 if (int_cst_range0 && tree_int_cst_sgn (vr0.min) >= 0)
2713 if (min == NULL_TREE)
2714 min = build_int_cst (expr_type, 0);
2715 if (max == NULL_TREE || tree_int_cst_lt (vr0.max, max))
2718 if (int_cst_range1 && tree_int_cst_sgn (vr1.min) >= 0)
2720 if (min == NULL_TREE)
2721 min = build_int_cst (expr_type, 0);
2722 if (max == NULL_TREE || tree_int_cst_lt (vr1.max, max))
2726 else if (!int_cst_range0
2728 || tree_int_cst_sgn (vr0.min) < 0
2729 || tree_int_cst_sgn (vr1.min) < 0)
2731 set_value_range_to_varying (vr);
2736 min = double_int_to_tree (expr_type,
2737 double_int_ior (must_be_nonzero0,
2739 max = double_int_to_tree (expr_type,
2740 double_int_ior (may_be_nonzero0,
2742 if (TREE_OVERFLOW (min) || tree_int_cst_sgn (min) < 0)
2745 min = vrp_int_const_binop (MAX_EXPR, min, vr0.min);
2746 if (TREE_OVERFLOW (max) || tree_int_cst_sgn (max) < 0)
2748 min = vrp_int_const_binop (MAX_EXPR, min, vr1.min);
2754 /* If either MIN or MAX overflowed, then set the resulting range to
2755 VARYING. But we do accept an overflow infinity
2757 if (min == NULL_TREE
2758 || !is_gimple_min_invariant (min)
2759 || (TREE_OVERFLOW (min) && !is_overflow_infinity (min))
2761 || !is_gimple_min_invariant (max)
2762 || (TREE_OVERFLOW (max) && !is_overflow_infinity (max)))
2764 set_value_range_to_varying (vr);
2770 2) [-INF, +-INF(OVF)]
2771 3) [+-INF(OVF), +INF]
2772 4) [+-INF(OVF), +-INF(OVF)]
2773 We learn nothing when we have INF and INF(OVF) on both sides.
2774 Note that we do accept [-INF, -INF] and [+INF, +INF] without
2776 if ((vrp_val_is_min (min) || is_overflow_infinity (min))
2777 && (vrp_val_is_max (max) || is_overflow_infinity (max)))
2779 set_value_range_to_varying (vr);
2783 cmp = compare_values (min, max);
2784 if (cmp == -2 || cmp == 1)
2786 /* If the new range has its limits swapped around (MIN > MAX),
2787 then the operation caused one of them to wrap around, mark
2788 the new range VARYING. */
2789 set_value_range_to_varying (vr);
2792 set_value_range (vr, type, min, max, NULL);
2796 /* Extract range information from a unary expression EXPR based on
2797 the range of its operand and the expression code. */
2800 extract_range_from_unary_expr (value_range_t *vr, enum tree_code code,
2801 tree type, tree op0)
2805 value_range_t vr0 = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
2807 /* Refuse to operate on certain unary expressions for which we
2808 cannot easily determine a resulting range. */
2809 if (code == FIX_TRUNC_EXPR
2810 || code == FLOAT_EXPR
2811 || code == BIT_NOT_EXPR
2812 || code == CONJ_EXPR)
2814 /* We can still do constant propagation here. */
2815 if ((op0 = op_with_constant_singleton_value_range (op0)) != NULL_TREE)
2817 tree tem = fold_unary (code, type, op0);
2819 && is_gimple_min_invariant (tem)
2820 && !is_overflow_infinity (tem))
2822 set_value_range (vr, VR_RANGE, tem, tem, NULL);
2826 set_value_range_to_varying (vr);
2830 /* Get value ranges for the operand. For constant operands, create
2831 a new value range with the operand to simplify processing. */
2832 if (TREE_CODE (op0) == SSA_NAME)
2833 vr0 = *(get_value_range (op0));
2834 else if (is_gimple_min_invariant (op0))
2835 set_value_range_to_value (&vr0, op0, NULL);
2837 set_value_range_to_varying (&vr0);
2839 /* If VR0 is UNDEFINED, so is the result. */
2840 if (vr0.type == VR_UNDEFINED)
2842 set_value_range_to_undefined (vr);
2846 /* Refuse to operate on symbolic ranges, or if neither operand is
2847 a pointer or integral type. */
2848 if ((!INTEGRAL_TYPE_P (TREE_TYPE (op0))
2849 && !POINTER_TYPE_P (TREE_TYPE (op0)))
2850 || (vr0.type != VR_VARYING
2851 && symbolic_range_p (&vr0)))
2853 set_value_range_to_varying (vr);
2857 /* If the expression involves pointers, we are only interested in
2858 determining if it evaluates to NULL [0, 0] or non-NULL (~[0, 0]). */
2859 if (POINTER_TYPE_P (type) || POINTER_TYPE_P (TREE_TYPE (op0)))
2864 if (range_is_nonnull (&vr0)
2865 || (tree_unary_nonzero_warnv_p (code, type, op0, &sop)
2867 set_value_range_to_nonnull (vr, type);
2868 else if (range_is_null (&vr0))
2869 set_value_range_to_null (vr, type);
2871 set_value_range_to_varying (vr);
2876 /* Handle unary expressions on integer ranges. */
2877 if (CONVERT_EXPR_CODE_P (code)
2878 && INTEGRAL_TYPE_P (type)
2879 && INTEGRAL_TYPE_P (TREE_TYPE (op0)))
2881 tree inner_type = TREE_TYPE (op0);
2882 tree outer_type = type;
2884 /* If VR0 is varying and we increase the type precision, assume
2885 a full range for the following transformation. */
2886 if (vr0.type == VR_VARYING
2887 && TYPE_PRECISION (inner_type) < TYPE_PRECISION (outer_type))
2889 vr0.type = VR_RANGE;
2890 vr0.min = TYPE_MIN_VALUE (inner_type);
2891 vr0.max = TYPE_MAX_VALUE (inner_type);
2894 /* If VR0 is a constant range or anti-range and the conversion is
2895 not truncating we can convert the min and max values and
2896 canonicalize the resulting range. Otherwise we can do the
2897 conversion if the size of the range is less than what the
2898 precision of the target type can represent and the range is
2899 not an anti-range. */
2900 if ((vr0.type == VR_RANGE
2901 || vr0.type == VR_ANTI_RANGE)
2902 && TREE_CODE (vr0.min) == INTEGER_CST
2903 && TREE_CODE (vr0.max) == INTEGER_CST
2904 && (!is_overflow_infinity (vr0.min)
2905 || (vr0.type == VR_RANGE
2906 && TYPE_PRECISION (outer_type) > TYPE_PRECISION (inner_type)
2907 && needs_overflow_infinity (outer_type)
2908 && supports_overflow_infinity (outer_type)))
2909 && (!is_overflow_infinity (vr0.max)
2910 || (vr0.type == VR_RANGE
2911 && TYPE_PRECISION (outer_type) > TYPE_PRECISION (inner_type)
2912 && needs_overflow_infinity (outer_type)
2913 && supports_overflow_infinity (outer_type)))
2914 && (TYPE_PRECISION (outer_type) >= TYPE_PRECISION (inner_type)
2915 || (vr0.type == VR_RANGE
2916 && integer_zerop (int_const_binop (RSHIFT_EXPR,
2917 int_const_binop (MINUS_EXPR, vr0.max, vr0.min),
2918 size_int (TYPE_PRECISION (outer_type)))))))
2920 tree new_min, new_max;
2921 new_min = force_fit_type_double (outer_type,
2922 tree_to_double_int (vr0.min),
2924 new_max = force_fit_type_double (outer_type,
2925 tree_to_double_int (vr0.max),
2927 if (is_overflow_infinity (vr0.min))
2928 new_min = negative_overflow_infinity (outer_type);
2929 if (is_overflow_infinity (vr0.max))
2930 new_max = positive_overflow_infinity (outer_type);
2931 set_and_canonicalize_value_range (vr, vr0.type,
2932 new_min, new_max, NULL);
2936 set_value_range_to_varying (vr);
2940 /* Conversion of a VR_VARYING value to a wider type can result
2941 in a usable range. So wait until after we've handled conversions
2942 before dropping the result to VR_VARYING if we had a source
2943 operand that is VR_VARYING. */
2944 if (vr0.type == VR_VARYING)
2946 set_value_range_to_varying (vr);
2950 /* Apply the operation to each end of the range and see what we end
2952 if (code == NEGATE_EXPR
2953 && !TYPE_UNSIGNED (type))
2955 /* NEGATE_EXPR flips the range around. We need to treat
2956 TYPE_MIN_VALUE specially. */
2957 if (is_positive_overflow_infinity (vr0.max))
2958 min = negative_overflow_infinity (type);
2959 else if (is_negative_overflow_infinity (vr0.max))
2960 min = positive_overflow_infinity (type);
2961 else if (!vrp_val_is_min (vr0.max))
2962 min = fold_unary_to_constant (code, type, vr0.max);
2963 else if (needs_overflow_infinity (type))
2965 if (supports_overflow_infinity (type)
2966 && !is_overflow_infinity (vr0.min)
2967 && !vrp_val_is_min (vr0.min))
2968 min = positive_overflow_infinity (type);
2971 set_value_range_to_varying (vr);
2976 min = TYPE_MIN_VALUE (type);
2978 if (is_positive_overflow_infinity (vr0.min))
2979 max = negative_overflow_infinity (type);
2980 else if (is_negative_overflow_infinity (vr0.min))
2981 max = positive_overflow_infinity (type);
2982 else if (!vrp_val_is_min (vr0.min))
2983 max = fold_unary_to_constant (code, type, vr0.min);
2984 else if (needs_overflow_infinity (type))
2986 if (supports_overflow_infinity (type))
2987 max = positive_overflow_infinity (type);
2990 set_value_range_to_varying (vr);
2995 max = TYPE_MIN_VALUE (type);
2997 else if (code == NEGATE_EXPR
2998 && TYPE_UNSIGNED (type))
3000 if (!range_includes_zero_p (&vr0))
3002 max = fold_unary_to_constant (code, type, vr0.min);
3003 min = fold_unary_to_constant (code, type, vr0.max);
3007 if (range_is_null (&vr0))
3008 set_value_range_to_null (vr, type);
3010 set_value_range_to_varying (vr);
3014 else if (code == ABS_EXPR
3015 && !TYPE_UNSIGNED (type))
3017 /* -TYPE_MIN_VALUE = TYPE_MIN_VALUE with flag_wrapv so we can't get a
3019 if (!TYPE_OVERFLOW_UNDEFINED (type)
3020 && ((vr0.type == VR_RANGE
3021 && vrp_val_is_min (vr0.min))
3022 || (vr0.type == VR_ANTI_RANGE
3023 && !vrp_val_is_min (vr0.min)
3024 && !range_includes_zero_p (&vr0))))
3026 set_value_range_to_varying (vr);
3030 /* ABS_EXPR may flip the range around, if the original range
3031 included negative values. */
3032 if (is_overflow_infinity (vr0.min))
3033 min = positive_overflow_infinity (type);
3034 else if (!vrp_val_is_min (vr0.min))
3035 min = fold_unary_to_constant (code, type, vr0.min);
3036 else if (!needs_overflow_infinity (type))
3037 min = TYPE_MAX_VALUE (type);
3038 else if (supports_overflow_infinity (type))
3039 min = positive_overflow_infinity (type);
3042 set_value_range_to_varying (vr);
3046 if (is_overflow_infinity (vr0.max))
3047 max = positive_overflow_infinity (type);
3048 else if (!vrp_val_is_min (vr0.max))
3049 max = fold_unary_to_constant (code, type, vr0.max);
3050 else if (!needs_overflow_infinity (type))
3051 max = TYPE_MAX_VALUE (type);
3052 else if (supports_overflow_infinity (type)
3053 /* We shouldn't generate [+INF, +INF] as set_value_range
3054 doesn't like this and ICEs. */
3055 && !is_positive_overflow_infinity (min))
3056 max = positive_overflow_infinity (type);
3059 set_value_range_to_varying (vr);
3063 cmp = compare_values (min, max);
3065 /* If a VR_ANTI_RANGEs contains zero, then we have
3066 ~[-INF, min(MIN, MAX)]. */
3067 if (vr0.type == VR_ANTI_RANGE)
3069 if (range_includes_zero_p (&vr0))
3071 /* Take the lower of the two values. */
3075 /* Create ~[-INF, min (abs(MIN), abs(MAX))]
3076 or ~[-INF + 1, min (abs(MIN), abs(MAX))] when
3077 flag_wrapv is set and the original anti-range doesn't include
3078 TYPE_MIN_VALUE, remember -TYPE_MIN_VALUE = TYPE_MIN_VALUE. */
3079 if (TYPE_OVERFLOW_WRAPS (type))
3081 tree type_min_value = TYPE_MIN_VALUE (type);
3083 min = (vr0.min != type_min_value
3084 ? int_const_binop (PLUS_EXPR, type_min_value,
3090 if (overflow_infinity_range_p (&vr0))
3091 min = negative_overflow_infinity (type);
3093 min = TYPE_MIN_VALUE (type);
3098 /* All else has failed, so create the range [0, INF], even for
3099 flag_wrapv since TYPE_MIN_VALUE is in the original
3101 vr0.type = VR_RANGE;
3102 min = build_int_cst (type, 0);
3103 if (needs_overflow_infinity (type))
3105 if (supports_overflow_infinity (type))
3106 max = positive_overflow_infinity (type);
3109 set_value_range_to_varying (vr);
3114 max = TYPE_MAX_VALUE (type);
3118 /* If the range contains zero then we know that the minimum value in the
3119 range will be zero. */
3120 else if (range_includes_zero_p (&vr0))
3124 min = build_int_cst (type, 0);
3128 /* If the range was reversed, swap MIN and MAX. */
3139 /* Otherwise, operate on each end of the range. */
3140 min = fold_unary_to_constant (code, type, vr0.min);
3141 max = fold_unary_to_constant (code, type, vr0.max);
3143 if (needs_overflow_infinity (type))
3145 gcc_assert (code != NEGATE_EXPR && code != ABS_EXPR);
3147 /* If both sides have overflowed, we don't know
3149 if ((is_overflow_infinity (vr0.min)
3150 || TREE_OVERFLOW (min))
3151 && (is_overflow_infinity (vr0.max)
3152 || TREE_OVERFLOW (max)))
3154 set_value_range_to_varying (vr);
3158 if (is_overflow_infinity (vr0.min))
3160 else if (TREE_OVERFLOW (min))
3162 if (supports_overflow_infinity (type))
3163 min = (tree_int_cst_sgn (min) >= 0
3164 ? positive_overflow_infinity (TREE_TYPE (min))
3165 : negative_overflow_infinity (TREE_TYPE (min)));
3168 set_value_range_to_varying (vr);
3173 if (is_overflow_infinity (vr0.max))
3175 else if (TREE_OVERFLOW (max))
3177 if (supports_overflow_infinity (type))
3178 max = (tree_int_cst_sgn (max) >= 0
3179 ? positive_overflow_infinity (TREE_TYPE (max))
3180 : negative_overflow_infinity (TREE_TYPE (max)));
3183 set_value_range_to_varying (vr);
3190 cmp = compare_values (min, max);
3191 if (cmp == -2 || cmp == 1)
3193 /* If the new range has its limits swapped around (MIN > MAX),
3194 then the operation caused one of them to wrap around, mark
3195 the new range VARYING. */
3196 set_value_range_to_varying (vr);
3199 set_value_range (vr, vr0.type, min, max, NULL);
3203 /* Extract range information from a conditional expression EXPR based on
3204 the ranges of each of its operands and the expression code. */
3207 extract_range_from_cond_expr (value_range_t *vr, tree expr)
3210 value_range_t vr0 = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
3211 value_range_t vr1 = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
3213 /* Get value ranges for each operand. For constant operands, create
3214 a new value range with the operand to simplify processing. */
3215 op0 = COND_EXPR_THEN (expr);
3216 if (TREE_CODE (op0) == SSA_NAME)
3217 vr0 = *(get_value_range (op0));
3218 else if (is_gimple_min_invariant (op0))
3219 set_value_range_to_value (&vr0, op0, NULL);
3221 set_value_range_to_varying (&vr0);
3223 op1 = COND_EXPR_ELSE (expr);
3224 if (TREE_CODE (op1) == SSA_NAME)
3225 vr1 = *(get_value_range (op1));
3226 else if (is_gimple_min_invariant (op1))
3227 set_value_range_to_value (&vr1, op1, NULL);
3229 set_value_range_to_varying (&vr1);
3231 /* The resulting value range is the union of the operand ranges */
3232 vrp_meet (&vr0, &vr1);
3233 copy_value_range (vr, &vr0);
3237 /* Extract range information from a comparison expression EXPR based
3238 on the range of its operand and the expression code. */
3241 extract_range_from_comparison (value_range_t *vr, enum tree_code code,
3242 tree type, tree op0, tree op1)
3247 val = vrp_evaluate_conditional_warnv_with_ops (code, op0, op1, false, &sop,
3250 /* A disadvantage of using a special infinity as an overflow
3251 representation is that we lose the ability to record overflow
3252 when we don't have an infinity. So we have to ignore a result
3253 which relies on overflow. */
3255 if (val && !is_overflow_infinity (val) && !sop)
3257 /* Since this expression was found on the RHS of an assignment,
3258 its type may be different from _Bool. Convert VAL to EXPR's
3260 val = fold_convert (type, val);
3261 if (is_gimple_min_invariant (val))
3262 set_value_range_to_value (vr, val, vr->equiv);
3264 set_value_range (vr, VR_RANGE, val, val, vr->equiv);
3267 /* The result of a comparison is always true or false. */
3268 set_value_range_to_truthvalue (vr, type);
3271 /* Try to derive a nonnegative or nonzero range out of STMT relying
3272 primarily on generic routines in fold in conjunction with range data.
3273 Store the result in *VR */
3276 extract_range_basic (value_range_t *vr, gimple stmt)
3279 tree type = gimple_expr_type (stmt);
3281 if (INTEGRAL_TYPE_P (type)
3282 && gimple_stmt_nonnegative_warnv_p (stmt, &sop))
3283 set_value_range_to_nonnegative (vr, type,
3284 sop || stmt_overflow_infinity (stmt));
3285 else if (vrp_stmt_computes_nonzero (stmt, &sop)
3287 set_value_range_to_nonnull (vr, type);
3289 set_value_range_to_varying (vr);
3293 /* Try to compute a useful range out of assignment STMT and store it
3297 extract_range_from_assignment (value_range_t *vr, gimple stmt)
3299 enum tree_code code = gimple_assign_rhs_code (stmt);
3301 if (code == ASSERT_EXPR)
3302 extract_range_from_assert (vr, gimple_assign_rhs1 (stmt));
3303 else if (code == SSA_NAME)
3304 extract_range_from_ssa_name (vr, gimple_assign_rhs1 (stmt));
3305 else if (TREE_CODE_CLASS (code) == tcc_binary)
3306 extract_range_from_binary_expr (vr, gimple_assign_rhs_code (stmt),
3307 gimple_expr_type (stmt),
3308 gimple_assign_rhs1 (stmt),
3309 gimple_assign_rhs2 (stmt));
3310 else if (TREE_CODE_CLASS (code) == tcc_unary)
3311 extract_range_from_unary_expr (vr, gimple_assign_rhs_code (stmt),
3312 gimple_expr_type (stmt),
3313 gimple_assign_rhs1 (stmt));
3314 else if (code == COND_EXPR)
3315 extract_range_from_cond_expr (vr, gimple_assign_rhs1 (stmt));
3316 else if (TREE_CODE_CLASS (code) == tcc_comparison)
3317 extract_range_from_comparison (vr, gimple_assign_rhs_code (stmt),
3318 gimple_expr_type (stmt),
3319 gimple_assign_rhs1 (stmt),
3320 gimple_assign_rhs2 (stmt));
3321 else if (get_gimple_rhs_class (code) == GIMPLE_SINGLE_RHS
3322 && is_gimple_min_invariant (gimple_assign_rhs1 (stmt)))
3323 set_value_range_to_value (vr, gimple_assign_rhs1 (stmt), NULL);
3325 set_value_range_to_varying (vr);
3327 if (vr->type == VR_VARYING)
3328 extract_range_basic (vr, stmt);
3331 /* Given a range VR, a LOOP and a variable VAR, determine whether it
3332 would be profitable to adjust VR using scalar evolution information
3333 for VAR. If so, update VR with the new limits. */
3336 adjust_range_with_scev (value_range_t *vr, struct loop *loop,
3337 gimple stmt, tree var)
3339 tree init, step, chrec, tmin, tmax, min, max, type, tem;
3340 enum ev_direction dir;
3342 /* TODO. Don't adjust anti-ranges. An anti-range may provide
3343 better opportunities than a regular range, but I'm not sure. */
3344 if (vr->type == VR_ANTI_RANGE)
3347 chrec = instantiate_parameters (loop, analyze_scalar_evolution (loop, var));
3349 /* Like in PR19590, scev can return a constant function. */
3350 if (is_gimple_min_invariant (chrec))
3352 set_value_range_to_value (vr, chrec, vr->equiv);
3356 if (TREE_CODE (chrec) != POLYNOMIAL_CHREC)
3359 init = initial_condition_in_loop_num (chrec, loop->num);
3360 tem = op_with_constant_singleton_value_range (init);
3363 step = evolution_part_in_loop_num (chrec, loop->num);
3364 tem = op_with_constant_singleton_value_range (step);
3368 /* If STEP is symbolic, we can't know whether INIT will be the
3369 minimum or maximum value in the range. Also, unless INIT is
3370 a simple expression, compare_values and possibly other functions
3371 in tree-vrp won't be able to handle it. */
3372 if (step == NULL_TREE
3373 || !is_gimple_min_invariant (step)
3374 || !valid_value_p (init))
3377 dir = scev_direction (chrec);
3378 if (/* Do not adjust ranges if we do not know whether the iv increases
3379 or decreases, ... */
3380 dir == EV_DIR_UNKNOWN
3381 /* ... or if it may wrap. */
3382 || scev_probably_wraps_p (init, step, stmt, get_chrec_loop (chrec),
3386 /* We use TYPE_MIN_VALUE and TYPE_MAX_VALUE here instead of
3387 negative_overflow_infinity and positive_overflow_infinity,
3388 because we have concluded that the loop probably does not
3391 type = TREE_TYPE (var);
3392 if (POINTER_TYPE_P (type) || !TYPE_MIN_VALUE (type))
3393 tmin = lower_bound_in_type (type, type);
3395 tmin = TYPE_MIN_VALUE (type);
3396 if (POINTER_TYPE_P (type) || !TYPE_MAX_VALUE (type))
3397 tmax = upper_bound_in_type (type, type);
3399 tmax = TYPE_MAX_VALUE (type);
3401 /* Try to use estimated number of iterations for the loop to constrain the
3402 final value in the evolution. */
3403 if (TREE_CODE (step) == INTEGER_CST
3404 && is_gimple_val (init)
3405 && (TREE_CODE (init) != SSA_NAME
3406 || get_value_range (init)->type == VR_RANGE))
3410 if (estimated_loop_iterations (loop, true, &nit))
3412 value_range_t maxvr = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
3414 bool unsigned_p = TYPE_UNSIGNED (TREE_TYPE (step));
3417 dtmp = double_int_mul_with_sign (tree_to_double_int (step), nit,
3418 unsigned_p, &overflow);
3419 /* If the multiplication overflowed we can't do a meaningful
3420 adjustment. Likewise if the result doesn't fit in the type
3421 of the induction variable. For a signed type we have to
3422 check whether the result has the expected signedness which
3423 is that of the step as number of iterations is unsigned. */
3425 && double_int_fits_to_tree_p (TREE_TYPE (init), dtmp)
3427 || ((dtmp.high ^ TREE_INT_CST_HIGH (step)) >= 0)))
3429 tem = double_int_to_tree (TREE_TYPE (init), dtmp);
3430 extract_range_from_binary_expr (&maxvr, PLUS_EXPR,
3431 TREE_TYPE (init), init, tem);
3432 /* Likewise if the addition did. */
3433 if (maxvr.type == VR_RANGE)
3442 if (vr->type == VR_VARYING || vr->type == VR_UNDEFINED)
3447 /* For VARYING or UNDEFINED ranges, just about anything we get
3448 from scalar evolutions should be better. */
3450 if (dir == EV_DIR_DECREASES)
3455 /* If we would create an invalid range, then just assume we
3456 know absolutely nothing. This may be over-conservative,
3457 but it's clearly safe, and should happen only in unreachable
3458 parts of code, or for invalid programs. */
3459 if (compare_values (min, max) == 1)
3462 set_value_range (vr, VR_RANGE, min, max, vr->equiv);
3464 else if (vr->type == VR_RANGE)
3469 if (dir == EV_DIR_DECREASES)
3471 /* INIT is the maximum value. If INIT is lower than VR->MAX
3472 but no smaller than VR->MIN, set VR->MAX to INIT. */
3473 if (compare_values (init, max) == -1)
3476 /* According to the loop information, the variable does not
3477 overflow. If we think it does, probably because of an
3478 overflow due to arithmetic on a different INF value,
3480 if (is_negative_overflow_infinity (min)
3481 || compare_values (min, tmin) == -1)
3487 /* If INIT is bigger than VR->MIN, set VR->MIN to INIT. */
3488 if (compare_values (init, min) == 1)
3491 if (is_positive_overflow_infinity (max)
3492 || compare_values (tmax, max) == -1)
3496 /* If we just created an invalid range with the minimum
3497 greater than the maximum, we fail conservatively.
3498 This should happen only in unreachable
3499 parts of code, or for invalid programs. */
3500 if (compare_values (min, max) == 1)
3503 set_value_range (vr, VR_RANGE, min, max, vr->equiv);
3507 /* Return true if VAR may overflow at STMT. This checks any available
3508 loop information to see if we can determine that VAR does not
3512 vrp_var_may_overflow (tree var, gimple stmt)
3515 tree chrec, init, step;
3517 if (current_loops == NULL)
3520 l = loop_containing_stmt (stmt);
3525 chrec = instantiate_parameters (l, analyze_scalar_evolution (l, var));
3526 if (TREE_CODE (chrec) != POLYNOMIAL_CHREC)
3529 init = initial_condition_in_loop_num (chrec, l->num);
3530 step = evolution_part_in_loop_num (chrec, l->num);
3532 if (step == NULL_TREE
3533 || !is_gimple_min_invariant (step)
3534 || !valid_value_p (init))
3537 /* If we get here, we know something useful about VAR based on the
3538 loop information. If it wraps, it may overflow. */
3540 if (scev_probably_wraps_p (init, step, stmt, get_chrec_loop (chrec),
3544 if (dump_file && (dump_flags & TDF_DETAILS) != 0)
3546 print_generic_expr (dump_file, var, 0);
3547 fprintf (dump_file, ": loop information indicates does not overflow\n");
3554 /* Given two numeric value ranges VR0, VR1 and a comparison code COMP:
3556 - Return BOOLEAN_TRUE_NODE if VR0 COMP VR1 always returns true for
3557 all the values in the ranges.
3559 - Return BOOLEAN_FALSE_NODE if the comparison always returns false.
3561 - Return NULL_TREE if it is not always possible to determine the
3562 value of the comparison.
3564 Also set *STRICT_OVERFLOW_P to indicate whether a range with an
3565 overflow infinity was used in the test. */
3569 compare_ranges (enum tree_code comp, value_range_t *vr0, value_range_t *vr1,
3570 bool *strict_overflow_p)
3572 /* VARYING or UNDEFINED ranges cannot be compared. */
3573 if (vr0->type == VR_VARYING
3574 || vr0->type == VR_UNDEFINED
3575 || vr1->type == VR_VARYING
3576 || vr1->type == VR_UNDEFINED)
3579 /* Anti-ranges need to be handled separately. */
3580 if (vr0->type == VR_ANTI_RANGE || vr1->type == VR_ANTI_RANGE)
3582 /* If both are anti-ranges, then we cannot compute any
3584 if (vr0->type == VR_ANTI_RANGE && vr1->type == VR_ANTI_RANGE)
3587 /* These comparisons are never statically computable. */
3594 /* Equality can be computed only between a range and an
3595 anti-range. ~[VAL1, VAL2] == [VAL1, VAL2] is always false. */
3596 if (vr0->type == VR_RANGE)
3598 /* To simplify processing, make VR0 the anti-range. */
3599 value_range_t *tmp = vr0;
3604 gcc_assert (comp == NE_EXPR || comp == EQ_EXPR);
3606 if (compare_values_warnv (vr0->min, vr1->min, strict_overflow_p) == 0
3607 && compare_values_warnv (vr0->max, vr1->max, strict_overflow_p) == 0)
3608 return (comp == NE_EXPR) ? boolean_true_node : boolean_false_node;
3613 if (!usable_range_p (vr0, strict_overflow_p)
3614 || !usable_range_p (vr1, strict_overflow_p))
3617 /* Simplify processing. If COMP is GT_EXPR or GE_EXPR, switch the
3618 operands around and change the comparison code. */
3619 if (comp == GT_EXPR || comp == GE_EXPR)
3622 comp = (comp == GT_EXPR) ? LT_EXPR : LE_EXPR;
3628 if (comp == EQ_EXPR)
3630 /* Equality may only be computed if both ranges represent
3631 exactly one value. */
3632 if (compare_values_warnv (vr0->min, vr0->max, strict_overflow_p) == 0
3633 && compare_values_warnv (vr1->min, vr1->max, strict_overflow_p) == 0)
3635 int cmp_min = compare_values_warnv (vr0->min, vr1->min,
3637 int cmp_max = compare_values_warnv (vr0->max, vr1->max,
3639 if (cmp_min == 0 && cmp_max == 0)
3640 return boolean_true_node;
3641 else if (cmp_min != -2 && cmp_max != -2)
3642 return boolean_false_node;
3644 /* If [V0_MIN, V1_MAX] < [V1_MIN, V1_MAX] then V0 != V1. */
3645 else if (compare_values_warnv (vr0->min, vr1->max,
3646 strict_overflow_p) == 1
3647 || compare_values_warnv (vr1->min, vr0->max,
3648 strict_overflow_p) == 1)
3649 return boolean_false_node;
3653 else if (comp == NE_EXPR)
3657 /* If VR0 is completely to the left or completely to the right
3658 of VR1, they are always different. Notice that we need to
3659 make sure that both comparisons yield similar results to
3660 avoid comparing values that cannot be compared at
3662 cmp1 = compare_values_warnv (vr0->max, vr1->min, strict_overflow_p);
3663 cmp2 = compare_values_warnv (vr0->min, vr1->max, strict_overflow_p);
3664 if ((cmp1 == -1 && cmp2 == -1) || (cmp1 == 1 && cmp2 == 1))
3665 return boolean_true_node;
3667 /* If VR0 and VR1 represent a single value and are identical,
3669 else if (compare_values_warnv (vr0->min, vr0->max,
3670 strict_overflow_p) == 0
3671 && compare_values_warnv (vr1->min, vr1->max,
3672 strict_overflow_p) == 0
3673 && compare_values_warnv (vr0->min, vr1->min,
3674 strict_overflow_p) == 0
3675 && compare_values_warnv (vr0->max, vr1->max,
3676 strict_overflow_p) == 0)
3677 return boolean_false_node;
3679 /* Otherwise, they may or may not be different. */
3683 else if (comp == LT_EXPR || comp == LE_EXPR)
3687 /* If VR0 is to the left of VR1, return true. */
3688 tst = compare_values_warnv (vr0->max, vr1->min, strict_overflow_p);
3689 if ((comp == LT_EXPR && tst == -1)
3690 || (comp == LE_EXPR && (tst == -1 || tst == 0)))
3692 if (overflow_infinity_range_p (vr0)
3693 || overflow_infinity_range_p (vr1))
3694 *strict_overflow_p = true;
3695 return boolean_true_node;
3698 /* If VR0 is to the right of VR1, return false. */
3699 tst = compare_values_warnv (vr0->min, vr1->max, strict_overflow_p);
3700 if ((comp == LT_EXPR && (tst == 0 || tst == 1))
3701 || (comp == LE_EXPR && tst == 1))
3703 if (overflow_infinity_range_p (vr0)
3704 || overflow_infinity_range_p (vr1))
3705 *strict_overflow_p = true;
3706 return boolean_false_node;
3709 /* Otherwise, we don't know. */
3717 /* Given a value range VR, a value VAL and a comparison code COMP, return
3718 BOOLEAN_TRUE_NODE if VR COMP VAL always returns true for all the
3719 values in VR. Return BOOLEAN_FALSE_NODE if the comparison
3720 always returns false. Return NULL_TREE if it is not always
3721 possible to determine the value of the comparison. Also set
3722 *STRICT_OVERFLOW_P to indicate whether a range with an overflow
3723 infinity was used in the test. */
3726 compare_range_with_value (enum tree_code comp, value_range_t *vr, tree val,
3727 bool *strict_overflow_p)
3729 if (vr->type == VR_VARYING || vr->type == VR_UNDEFINED)
3732 /* Anti-ranges need to be handled separately. */
3733 if (vr->type == VR_ANTI_RANGE)
3735 /* For anti-ranges, the only predicates that we can compute at
3736 compile time are equality and inequality. */
3743 /* ~[VAL_1, VAL_2] OP VAL is known if VAL_1 <= VAL <= VAL_2. */
3744 if (value_inside_range (val, vr) == 1)
3745 return (comp == NE_EXPR) ? boolean_true_node : boolean_false_node;
3750 if (!usable_range_p (vr, strict_overflow_p))
3753 if (comp == EQ_EXPR)
3755 /* EQ_EXPR may only be computed if VR represents exactly
3757 if (compare_values_warnv (vr->min, vr->max, strict_overflow_p) == 0)
3759 int cmp = compare_values_warnv (vr->min, val, strict_overflow_p);
3761 return boolean_true_node;
3762 else if (cmp == -1 || cmp == 1 || cmp == 2)
3763 return boolean_false_node;
3765 else if (compare_values_warnv (val, vr->min, strict_overflow_p) == -1
3766 || compare_values_warnv (vr->max, val, strict_overflow_p) == -1)
3767 return boolean_false_node;
3771 else if (comp == NE_EXPR)
3773 /* If VAL is not inside VR, then they are always different. */
3774 if (compare_values_warnv (vr->max, val, strict_overflow_p) == -1
3775 || compare_values_warnv (vr->min, val, strict_overflow_p) == 1)
3776 return boolean_true_node;
3778 /* If VR represents exactly one value equal to VAL, then return
3780 if (compare_values_warnv (vr->min, vr->max, strict_overflow_p) == 0
3781 && compare_values_warnv (vr->min, val, strict_overflow_p) == 0)
3782 return boolean_false_node;
3784 /* Otherwise, they may or may not be different. */
3787 else if (comp == LT_EXPR || comp == LE_EXPR)
3791 /* If VR is to the left of VAL, return true. */
3792 tst = compare_values_warnv (vr->max, val, strict_overflow_p);
3793 if ((comp == LT_EXPR && tst == -1)
3794 || (comp == LE_EXPR && (tst == -1 || tst == 0)))
3796 if (overflow_infinity_range_p (vr))
3797 *strict_overflow_p = true;
3798 return boolean_true_node;
3801 /* If VR is to the right of VAL, return false. */
3802 tst = compare_values_warnv (vr->min, val, strict_overflow_p);
3803 if ((comp == LT_EXPR && (tst == 0 || tst == 1))
3804 || (comp == LE_EXPR && tst == 1))
3806 if (overflow_infinity_range_p (vr))
3807 *strict_overflow_p = true;
3808 return boolean_false_node;
3811 /* Otherwise, we don't know. */
3814 else if (comp == GT_EXPR || comp == GE_EXPR)
3818 /* If VR is to the right of VAL, return true. */
3819 tst = compare_values_warnv (vr->min, val, strict_overflow_p);
3820 if ((comp == GT_EXPR && tst == 1)
3821 || (comp == GE_EXPR && (tst == 0 || tst == 1)))
3823 if (overflow_infinity_range_p (vr))
3824 *strict_overflow_p = true;
3825 return boolean_true_node;
3828 /* If VR is to the left of VAL, return false. */
3829 tst = compare_values_warnv (vr->max, val, strict_overflow_p);
3830 if ((comp == GT_EXPR && (tst == -1 || tst == 0))
3831 || (comp == GE_EXPR && tst == -1))
3833 if (overflow_infinity_range_p (vr))
3834 *strict_overflow_p = true;
3835 return boolean_false_node;
3838 /* Otherwise, we don't know. */
3846 /* Debugging dumps. */
3848 void dump_value_range (FILE *, value_range_t *);
3849 void debug_value_range (value_range_t *);
3850 void dump_all_value_ranges (FILE *);
3851 void debug_all_value_ranges (void);
3852 void dump_vr_equiv (FILE *, bitmap);
3853 void debug_vr_equiv (bitmap);
3856 /* Dump value range VR to FILE. */
3859 dump_value_range (FILE *file, value_range_t *vr)
3862 fprintf (file, "[]");
3863 else if (vr->type == VR_UNDEFINED)
3864 fprintf (file, "UNDEFINED");
3865 else if (vr->type == VR_RANGE || vr->type == VR_ANTI_RANGE)
3867 tree type = TREE_TYPE (vr->min);
3869 fprintf (file, "%s[", (vr->type == VR_ANTI_RANGE) ? "~" : "");
3871 if (is_negative_overflow_infinity (vr->min))
3872 fprintf (file, "-INF(OVF)");
3873 else if (INTEGRAL_TYPE_P (type)
3874 && !TYPE_UNSIGNED (type)
3875 && vrp_val_is_min (vr->min))
3876 fprintf (file, "-INF");
3878 print_generic_expr (file, vr->min, 0);
3880 fprintf (file, ", ");
3882 if (is_positive_overflow_infinity (vr->max))
3883 fprintf (file, "+INF(OVF)");
3884 else if (INTEGRAL_TYPE_P (type)
3885 && vrp_val_is_max (vr->max))
3886 fprintf (file, "+INF");
3888 print_generic_expr (file, vr->max, 0);
3890 fprintf (file, "]");
3897 fprintf (file, " EQUIVALENCES: { ");
3899 EXECUTE_IF_SET_IN_BITMAP (vr->equiv, 0, i, bi)
3901 print_generic_expr (file, ssa_name (i), 0);
3902 fprintf (file, " ");
3906 fprintf (file, "} (%u elements)", c);
3909 else if (vr->type == VR_VARYING)
3910 fprintf (file, "VARYING");
3912 fprintf (file, "INVALID RANGE");
3916 /* Dump value range VR to stderr. */
3919 debug_value_range (value_range_t *vr)
3921 dump_value_range (stderr, vr);
3922 fprintf (stderr, "\n");
3926 /* Dump value ranges of all SSA_NAMEs to FILE. */
3929 dump_all_value_ranges (FILE *file)
3933 for (i = 0; i < num_vr_values; i++)
3937 print_generic_expr (file, ssa_name (i), 0);
3938 fprintf (file, ": ");
3939 dump_value_range (file, vr_value[i]);
3940 fprintf (file, "\n");
3944 fprintf (file, "\n");
3948 /* Dump all value ranges to stderr. */
3951 debug_all_value_ranges (void)
3953 dump_all_value_ranges (stderr);
3957 /* Given a COND_EXPR COND of the form 'V OP W', and an SSA name V,
3958 create a new SSA name N and return the assertion assignment
3959 'V = ASSERT_EXPR <V, V OP W>'. */
3962 build_assert_expr_for (tree cond, tree v)
3967 gcc_assert (TREE_CODE (v) == SSA_NAME);
3968 n = duplicate_ssa_name (v, NULL);
3970 if (COMPARISON_CLASS_P (cond))
3972 tree a = build2 (ASSERT_EXPR, TREE_TYPE (v), v, cond);
3973 assertion = gimple_build_assign (n, a);
3975 else if (TREE_CODE (cond) == TRUTH_NOT_EXPR)
3977 /* Given !V, build the assignment N = false. */
3978 tree op0 = TREE_OPERAND (cond, 0);
3979 gcc_assert (op0 == v);
3980 assertion = gimple_build_assign (n, boolean_false_node);
3982 else if (TREE_CODE (cond) == SSA_NAME)
3984 /* Given V, build the assignment N = true. */
3985 gcc_assert (v == cond);
3986 assertion = gimple_build_assign (n, boolean_true_node);
3991 SSA_NAME_DEF_STMT (n) = assertion;
3993 /* The new ASSERT_EXPR, creates a new SSA name that replaces the
3994 operand of the ASSERT_EXPR. Register the new name and the old one
3995 in the replacement table so that we can fix the SSA web after
3996 adding all the ASSERT_EXPRs. */
3997 register_new_name_mapping (n, v);
4003 /* Return false if EXPR is a predicate expression involving floating
4007 fp_predicate (gimple stmt)
4009 GIMPLE_CHECK (stmt, GIMPLE_COND);
4011 return FLOAT_TYPE_P (TREE_TYPE (gimple_cond_lhs (stmt)));
4015 /* If the range of values taken by OP can be inferred after STMT executes,
4016 return the comparison code (COMP_CODE_P) and value (VAL_P) that
4017 describes the inferred range. Return true if a range could be
4021 infer_value_range (gimple stmt, tree op, enum tree_code *comp_code_p, tree *val_p)
4024 *comp_code_p = ERROR_MARK;
4026 /* Do not attempt to infer anything in names that flow through
4028 if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (op))
4031 /* Similarly, don't infer anything from statements that may throw
4033 if (stmt_could_throw_p (stmt))
4036 /* If STMT is the last statement of a basic block with no
4037 successors, there is no point inferring anything about any of its
4038 operands. We would not be able to find a proper insertion point
4039 for the assertion, anyway. */
4040 if (stmt_ends_bb_p (stmt) && EDGE_COUNT (gimple_bb (stmt)->succs) == 0)
4043 /* We can only assume that a pointer dereference will yield
4044 non-NULL if -fdelete-null-pointer-checks is enabled. */
4045 if (flag_delete_null_pointer_checks
4046 && POINTER_TYPE_P (TREE_TYPE (op))
4047 && gimple_code (stmt) != GIMPLE_ASM)
4049 unsigned num_uses, num_loads, num_stores;
4051 count_uses_and_derefs (op, stmt, &num_uses, &num_loads, &num_stores);
4052 if (num_loads + num_stores > 0)
4054 *val_p = build_int_cst (TREE_TYPE (op), 0);
4055 *comp_code_p = NE_EXPR;
4064 void dump_asserts_for (FILE *, tree);
4065 void debug_asserts_for (tree);
4066 void dump_all_asserts (FILE *);
4067 void debug_all_asserts (void);
4069 /* Dump all the registered assertions for NAME to FILE. */
4072 dump_asserts_for (FILE *file, tree name)
4076 fprintf (file, "Assertions to be inserted for ");
4077 print_generic_expr (file, name, 0);
4078 fprintf (file, "\n");
4080 loc = asserts_for[SSA_NAME_VERSION (name)];
4083 fprintf (file, "\t");
4084 print_gimple_stmt (file, gsi_stmt (loc->si), 0, 0);
4085 fprintf (file, "\n\tBB #%d", loc->bb->index);
4088 fprintf (file, "\n\tEDGE %d->%d", loc->e->src->index,
4089 loc->e->dest->index);
4090 dump_edge_info (file, loc->e, 0);
4092 fprintf (file, "\n\tPREDICATE: ");
4093 print_generic_expr (file, name, 0);
4094 fprintf (file, " %s ", tree_code_name[(int)loc->comp_code]);
4095 print_generic_expr (file, loc->val, 0);
4096 fprintf (file, "\n\n");
4100 fprintf (file, "\n");
4104 /* Dump all the registered assertions for NAME to stderr. */
4107 debug_asserts_for (tree name)
4109 dump_asserts_for (stderr, name);
4113 /* Dump all the registered assertions for all the names to FILE. */
4116 dump_all_asserts (FILE *file)
4121 fprintf (file, "\nASSERT_EXPRs to be inserted\n\n");
4122 EXECUTE_IF_SET_IN_BITMAP (need_assert_for, 0, i, bi)
4123 dump_asserts_for (file, ssa_name (i));
4124 fprintf (file, "\n");
4128 /* Dump all the registered assertions for all the names to stderr. */
4131 debug_all_asserts (void)
4133 dump_all_asserts (stderr);
4137 /* If NAME doesn't have an ASSERT_EXPR registered for asserting
4138 'EXPR COMP_CODE VAL' at a location that dominates block BB or
4139 E->DEST, then register this location as a possible insertion point
4140 for ASSERT_EXPR <NAME, EXPR COMP_CODE VAL>.
4142 BB, E and SI provide the exact insertion point for the new
4143 ASSERT_EXPR. If BB is NULL, then the ASSERT_EXPR is to be inserted
4144 on edge E. Otherwise, if E is NULL, the ASSERT_EXPR is inserted on
4145 BB. If SI points to a COND_EXPR or a SWITCH_EXPR statement, then E
4146 must not be NULL. */
4149 register_new_assert_for (tree name, tree expr,
4150 enum tree_code comp_code,
4154 gimple_stmt_iterator si)
4156 assert_locus_t n, loc, last_loc;
4157 basic_block dest_bb;
4159 gcc_checking_assert (bb == NULL || e == NULL);
4162 gcc_checking_assert (gimple_code (gsi_stmt (si)) != GIMPLE_COND
4163 && gimple_code (gsi_stmt (si)) != GIMPLE_SWITCH);
4165 /* Never build an assert comparing against an integer constant with
4166 TREE_OVERFLOW set. This confuses our undefined overflow warning
4168 if (TREE_CODE (val) == INTEGER_CST
4169 && TREE_OVERFLOW (val))
4170 val = build_int_cst_wide (TREE_TYPE (val),
4171 TREE_INT_CST_LOW (val), TREE_INT_CST_HIGH (val));
4173 /* The new assertion A will be inserted at BB or E. We need to
4174 determine if the new location is dominated by a previously
4175 registered location for A. If we are doing an edge insertion,
4176 assume that A will be inserted at E->DEST. Note that this is not
4179 If E is a critical edge, it will be split. But even if E is
4180 split, the new block will dominate the same set of blocks that
4183 The reverse, however, is not true, blocks dominated by E->DEST
4184 will not be dominated by the new block created to split E. So,
4185 if the insertion location is on a critical edge, we will not use
4186 the new location to move another assertion previously registered
4187 at a block dominated by E->DEST. */
4188 dest_bb = (bb) ? bb : e->dest;
4190 /* If NAME already has an ASSERT_EXPR registered for COMP_CODE and
4191 VAL at a block dominating DEST_BB, then we don't need to insert a new
4192 one. Similarly, if the same assertion already exists at a block
4193 dominated by DEST_BB and the new location is not on a critical
4194 edge, then update the existing location for the assertion (i.e.,
4195 move the assertion up in the dominance tree).
4197 Note, this is implemented as a simple linked list because there
4198 should not be more than a handful of assertions registered per
4199 name. If this becomes a performance problem, a table hashed by
4200 COMP_CODE and VAL could be implemented. */
4201 loc = asserts_for[SSA_NAME_VERSION (name)];
4205 if (loc->comp_code == comp_code
4207 || operand_equal_p (loc->val, val, 0))
4208 && (loc->expr == expr
4209 || operand_equal_p (loc->expr, expr, 0)))
4211 /* If the assertion NAME COMP_CODE VAL has already been
4212 registered at a basic block that dominates DEST_BB, then
4213 we don't need to insert the same assertion again. Note
4214 that we don't check strict dominance here to avoid
4215 replicating the same assertion inside the same basic
4216 block more than once (e.g., when a pointer is
4217 dereferenced several times inside a block).
4219 An exception to this rule are edge insertions. If the
4220 new assertion is to be inserted on edge E, then it will
4221 dominate all the other insertions that we may want to
4222 insert in DEST_BB. So, if we are doing an edge
4223 insertion, don't do this dominance check. */
4225 && dominated_by_p (CDI_DOMINATORS, dest_bb, loc->bb))
4228 /* Otherwise, if E is not a critical edge and DEST_BB
4229 dominates the existing location for the assertion, move
4230 the assertion up in the dominance tree by updating its
4231 location information. */
4232 if ((e == NULL || !EDGE_CRITICAL_P (e))
4233 && dominated_by_p (CDI_DOMINATORS, loc->bb, dest_bb))
4242 /* Update the last node of the list and move to the next one. */
4247 /* If we didn't find an assertion already registered for
4248 NAME COMP_CODE VAL, add a new one at the end of the list of
4249 assertions associated with NAME. */
4250 n = XNEW (struct assert_locus_d);
4254 n->comp_code = comp_code;
4262 asserts_for[SSA_NAME_VERSION (name)] = n;
4264 bitmap_set_bit (need_assert_for, SSA_NAME_VERSION (name));
4267 /* (COND_OP0 COND_CODE COND_OP1) is a predicate which uses NAME.
4268 Extract a suitable test code and value and store them into *CODE_P and
4269 *VAL_P so the predicate is normalized to NAME *CODE_P *VAL_P.
4271 If no extraction was possible, return FALSE, otherwise return TRUE.
4273 If INVERT is true, then we invert the result stored into *CODE_P. */
4276 extract_code_and_val_from_cond_with_ops (tree name, enum tree_code cond_code,
4277 tree cond_op0, tree cond_op1,
4278 bool invert, enum tree_code *code_p,
4281 enum tree_code comp_code;
4284 /* Otherwise, we have a comparison of the form NAME COMP VAL
4285 or VAL COMP NAME. */
4286 if (name == cond_op1)
4288 /* If the predicate is of the form VAL COMP NAME, flip
4289 COMP around because we need to register NAME as the
4290 first operand in the predicate. */
4291 comp_code = swap_tree_comparison (cond_code);
4296 /* The comparison is of the form NAME COMP VAL, so the
4297 comparison code remains unchanged. */
4298 comp_code = cond_code;
4302 /* Invert the comparison code as necessary. */
4304 comp_code = invert_tree_comparison (comp_code, 0);
4306 /* VRP does not handle float types. */
4307 if (SCALAR_FLOAT_TYPE_P (TREE_TYPE (val)))
4310 /* Do not register always-false predicates.
4311 FIXME: this works around a limitation in fold() when dealing with
4312 enumerations. Given 'enum { N1, N2 } x;', fold will not
4313 fold 'if (x > N2)' to 'if (0)'. */
4314 if ((comp_code == GT_EXPR || comp_code == LT_EXPR)
4315 && INTEGRAL_TYPE_P (TREE_TYPE (val)))
4317 tree min = TYPE_MIN_VALUE (TREE_TYPE (val));
4318 tree max = TYPE_MAX_VALUE (TREE_TYPE (val));
4320 if (comp_code == GT_EXPR
4322 || compare_values (val, max) == 0))
4325 if (comp_code == LT_EXPR
4327 || compare_values (val, min) == 0))
4330 *code_p = comp_code;
4335 /* Try to register an edge assertion for SSA name NAME on edge E for
4336 the condition COND contributing to the conditional jump pointed to by BSI.
4337 Invert the condition COND if INVERT is true.
4338 Return true if an assertion for NAME could be registered. */
4341 register_edge_assert_for_2 (tree name, edge e, gimple_stmt_iterator bsi,
4342 enum tree_code cond_code,
4343 tree cond_op0, tree cond_op1, bool invert)
4346 enum tree_code comp_code;
4347 bool retval = false;
4349 if (!extract_code_and_val_from_cond_with_ops (name, cond_code,
4352 invert, &comp_code, &val))
4355 /* Only register an ASSERT_EXPR if NAME was found in the sub-graph
4356 reachable from E. */
4357 if (live_on_edge (e, name)
4358 && !has_single_use (name))
4360 register_new_assert_for (name, name, comp_code, val, NULL, e, bsi);
4364 /* In the case of NAME <= CST and NAME being defined as
4365 NAME = (unsigned) NAME2 + CST2 we can assert NAME2 >= -CST2
4366 and NAME2 <= CST - CST2. We can do the same for NAME > CST.
4367 This catches range and anti-range tests. */
4368 if ((comp_code == LE_EXPR
4369 || comp_code == GT_EXPR)
4370 && TREE_CODE (val) == INTEGER_CST
4371 && TYPE_UNSIGNED (TREE_TYPE (val)))
4373 gimple def_stmt = SSA_NAME_DEF_STMT (name);
4374 tree cst2 = NULL_TREE, name2 = NULL_TREE, name3 = NULL_TREE;
4376 /* Extract CST2 from the (optional) addition. */
4377 if (is_gimple_assign (def_stmt)
4378 && gimple_assign_rhs_code (def_stmt) == PLUS_EXPR)
4380 name2 = gimple_assign_rhs1 (def_stmt);
4381 cst2 = gimple_assign_rhs2 (def_stmt);
4382 if (TREE_CODE (name2) == SSA_NAME
4383 && TREE_CODE (cst2) == INTEGER_CST)
4384 def_stmt = SSA_NAME_DEF_STMT (name2);
4387 /* Extract NAME2 from the (optional) sign-changing cast. */
4388 if (gimple_assign_cast_p (def_stmt))
4390 if (CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (def_stmt))
4391 && ! TYPE_UNSIGNED (TREE_TYPE (gimple_assign_rhs1 (def_stmt)))
4392 && (TYPE_PRECISION (gimple_expr_type (def_stmt))
4393 == TYPE_PRECISION (TREE_TYPE (gimple_assign_rhs1 (def_stmt)))))
4394 name3 = gimple_assign_rhs1 (def_stmt);
4397 /* If name3 is used later, create an ASSERT_EXPR for it. */
4398 if (name3 != NULL_TREE
4399 && TREE_CODE (name3) == SSA_NAME
4400 && (cst2 == NULL_TREE
4401 || TREE_CODE (cst2) == INTEGER_CST)
4402 && INTEGRAL_TYPE_P (TREE_TYPE (name3))
4403 && live_on_edge (e, name3)
4404 && !has_single_use (name3))
4408 /* Build an expression for the range test. */
4409 tmp = build1 (NOP_EXPR, TREE_TYPE (name), name3);
4410 if (cst2 != NULL_TREE)
4411 tmp = build2 (PLUS_EXPR, TREE_TYPE (name), tmp, cst2);
4415 fprintf (dump_file, "Adding assert for ");
4416 print_generic_expr (dump_file, name3, 0);
4417 fprintf (dump_file, " from ");
4418 print_generic_expr (dump_file, tmp, 0);
4419 fprintf (dump_file, "\n");
4422 register_new_assert_for (name3, tmp, comp_code, val, NULL, e, bsi);
4427 /* If name2 is used later, create an ASSERT_EXPR for it. */
4428 if (name2 != NULL_TREE
4429 && TREE_CODE (name2) == SSA_NAME
4430 && TREE_CODE (cst2) == INTEGER_CST
4431 && INTEGRAL_TYPE_P (TREE_TYPE (name2))
4432 && live_on_edge (e, name2)
4433 && !has_single_use (name2))
4437 /* Build an expression for the range test. */
4439 if (TREE_TYPE (name) != TREE_TYPE (name2))
4440 tmp = build1 (NOP_EXPR, TREE_TYPE (name), tmp);
4441 if (cst2 != NULL_TREE)
4442 tmp = build2 (PLUS_EXPR, TREE_TYPE (name), tmp, cst2);
4446 fprintf (dump_file, "Adding assert for ");
4447 print_generic_expr (dump_file, name2, 0);
4448 fprintf (dump_file, " from ");
4449 print_generic_expr (dump_file, tmp, 0);
4450 fprintf (dump_file, "\n");
4453 register_new_assert_for (name2, tmp, comp_code, val, NULL, e, bsi);
4462 /* OP is an operand of a truth value expression which is known to have
4463 a particular value. Register any asserts for OP and for any
4464 operands in OP's defining statement.
4466 If CODE is EQ_EXPR, then we want to register OP is zero (false),
4467 if CODE is NE_EXPR, then we want to register OP is nonzero (true). */
4470 register_edge_assert_for_1 (tree op, enum tree_code code,
4471 edge e, gimple_stmt_iterator bsi)
4473 bool retval = false;
4476 enum tree_code rhs_code;
4478 /* We only care about SSA_NAMEs. */
4479 if (TREE_CODE (op) != SSA_NAME)
4482 /* We know that OP will have a zero or nonzero value. If OP is used
4483 more than once go ahead and register an assert for OP.
4485 The FOUND_IN_SUBGRAPH support is not helpful in this situation as
4486 it will always be set for OP (because OP is used in a COND_EXPR in
4488 if (!has_single_use (op))
4490 val = build_int_cst (TREE_TYPE (op), 0);
4491 register_new_assert_for (op, op, code, val, NULL, e, bsi);
4495 /* Now look at how OP is set. If it's set from a comparison,
4496 a truth operation or some bit operations, then we may be able
4497 to register information about the operands of that assignment. */
4498 op_def = SSA_NAME_DEF_STMT (op);
4499 if (gimple_code (op_def) != GIMPLE_ASSIGN)
4502 rhs_code = gimple_assign_rhs_code (op_def);
4504 if (TREE_CODE_CLASS (rhs_code) == tcc_comparison)
4506 bool invert = (code == EQ_EXPR ? true : false);
4507 tree op0 = gimple_assign_rhs1 (op_def);
4508 tree op1 = gimple_assign_rhs2 (op_def);
4510 if (TREE_CODE (op0) == SSA_NAME)
4511 retval |= register_edge_assert_for_2 (op0, e, bsi, rhs_code, op0, op1,
4513 if (TREE_CODE (op1) == SSA_NAME)
4514 retval |= register_edge_assert_for_2 (op1, e, bsi, rhs_code, op0, op1,
4517 else if ((code == NE_EXPR
4518 && gimple_assign_rhs_code (op_def) == BIT_AND_EXPR)
4520 && gimple_assign_rhs_code (op_def) == BIT_IOR_EXPR))
4522 /* Recurse on each operand. */
4523 retval |= register_edge_assert_for_1 (gimple_assign_rhs1 (op_def),
4525 retval |= register_edge_assert_for_1 (gimple_assign_rhs2 (op_def),
4528 else if (gimple_assign_rhs_code (op_def) == TRUTH_NOT_EXPR)
4530 /* Recurse, flipping CODE. */
4531 code = invert_tree_comparison (code, false);
4532 retval |= register_edge_assert_for_1 (gimple_assign_rhs1 (op_def),
4535 else if (gimple_assign_rhs_code (op_def) == SSA_NAME)
4537 /* Recurse through the copy. */
4538 retval |= register_edge_assert_for_1 (gimple_assign_rhs1 (op_def),
4541 else if (CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (op_def)))
4543 /* Recurse through the type conversion. */
4544 retval |= register_edge_assert_for_1 (gimple_assign_rhs1 (op_def),
4551 /* Try to register an edge assertion for SSA name NAME on edge E for
4552 the condition COND contributing to the conditional jump pointed to by SI.
4553 Return true if an assertion for NAME could be registered. */
4556 register_edge_assert_for (tree name, edge e, gimple_stmt_iterator si,
4557 enum tree_code cond_code, tree cond_op0,
4561 enum tree_code comp_code;
4562 bool retval = false;
4563 bool is_else_edge = (e->flags & EDGE_FALSE_VALUE) != 0;
4565 /* Do not attempt to infer anything in names that flow through
4567 if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (name))
4570 if (!extract_code_and_val_from_cond_with_ops (name, cond_code,
4576 /* Register ASSERT_EXPRs for name. */
4577 retval |= register_edge_assert_for_2 (name, e, si, cond_code, cond_op0,
4578 cond_op1, is_else_edge);
4581 /* If COND is effectively an equality test of an SSA_NAME against
4582 the value zero or one, then we may be able to assert values
4583 for SSA_NAMEs which flow into COND. */
4585 /* In the case of NAME == 1 or NAME != 0, for BIT_AND_EXPR defining
4586 statement of NAME we can assert both operands of the BIT_AND_EXPR
4587 have nonzero value. */
4588 if (((comp_code == EQ_EXPR && integer_onep (val))
4589 || (comp_code == NE_EXPR && integer_zerop (val))))
4591 gimple def_stmt = SSA_NAME_DEF_STMT (name);
4593 if (is_gimple_assign (def_stmt)
4594 && gimple_assign_rhs_code (def_stmt) == BIT_AND_EXPR)
4596 tree op0 = gimple_assign_rhs1 (def_stmt);
4597 tree op1 = gimple_assign_rhs2 (def_stmt);
4598 retval |= register_edge_assert_for_1 (op0, NE_EXPR, e, si);
4599 retval |= register_edge_assert_for_1 (op1, NE_EXPR, e, si);
4603 /* In the case of NAME == 0 or NAME != 1, for BIT_IOR_EXPR defining
4604 statement of NAME we can assert both operands of the BIT_IOR_EXPR
4606 if (((comp_code == EQ_EXPR && integer_zerop (val))
4607 || (comp_code == NE_EXPR && integer_onep (val))))
4609 gimple def_stmt = SSA_NAME_DEF_STMT (name);
4611 /* For BIT_IOR_EXPR only if NAME == 0 both operands have
4612 necessarily zero value, or if type-precision is one. */
4613 if (is_gimple_assign (def_stmt)
4614 && (gimple_assign_rhs_code (def_stmt) == BIT_IOR_EXPR
4615 && (TYPE_PRECISION (TREE_TYPE (name)) == 1
4616 || comp_code == EQ_EXPR)))
4618 tree op0 = gimple_assign_rhs1 (def_stmt);
4619 tree op1 = gimple_assign_rhs2 (def_stmt);
4620 retval |= register_edge_assert_for_1 (op0, EQ_EXPR, e, si);
4621 retval |= register_edge_assert_for_1 (op1, EQ_EXPR, e, si);
4629 /* Determine whether the outgoing edges of BB should receive an
4630 ASSERT_EXPR for each of the operands of BB's LAST statement.
4631 The last statement of BB must be a COND_EXPR.
4633 If any of the sub-graphs rooted at BB have an interesting use of
4634 the predicate operands, an assert location node is added to the
4635 list of assertions for the corresponding operands. */
4638 find_conditional_asserts (basic_block bb, gimple last)
4641 gimple_stmt_iterator bsi;
4647 need_assert = false;
4648 bsi = gsi_for_stmt (last);
4650 /* Look for uses of the operands in each of the sub-graphs
4651 rooted at BB. We need to check each of the outgoing edges
4652 separately, so that we know what kind of ASSERT_EXPR to
4654 FOR_EACH_EDGE (e, ei, bb->succs)
4659 /* Register the necessary assertions for each operand in the
4660 conditional predicate. */
4661 FOR_EACH_SSA_TREE_OPERAND (op, last, iter, SSA_OP_USE)
4663 need_assert |= register_edge_assert_for (op, e, bsi,
4664 gimple_cond_code (last),
4665 gimple_cond_lhs (last),
4666 gimple_cond_rhs (last));
4679 /* Compare two case labels sorting first by the destination bb index
4680 and then by the case value. */
4683 compare_case_labels (const void *p1, const void *p2)
4685 const struct case_info *ci1 = (const struct case_info *) p1;
4686 const struct case_info *ci2 = (const struct case_info *) p2;
4687 int idx1 = ci1->bb->index;
4688 int idx2 = ci2->bb->index;
4692 else if (idx1 == idx2)
4694 /* Make sure the default label is first in a group. */
4695 if (!CASE_LOW (ci1->expr))
4697 else if (!CASE_LOW (ci2->expr))
4700 return tree_int_cst_compare (CASE_LOW (ci1->expr),
4701 CASE_LOW (ci2->expr));
4707 /* Determine whether the outgoing edges of BB should receive an
4708 ASSERT_EXPR for each of the operands of BB's LAST statement.
4709 The last statement of BB must be a SWITCH_EXPR.
4711 If any of the sub-graphs rooted at BB have an interesting use of
4712 the predicate operands, an assert location node is added to the
4713 list of assertions for the corresponding operands. */
4716 find_switch_asserts (basic_block bb, gimple last)
4719 gimple_stmt_iterator bsi;
4722 struct case_info *ci;
4723 size_t n = gimple_switch_num_labels (last);
4724 #if GCC_VERSION >= 4000
4727 /* Work around GCC 3.4 bug (PR 37086). */
4728 volatile unsigned int idx;
4731 need_assert = false;
4732 bsi = gsi_for_stmt (last);
4733 op = gimple_switch_index (last);
4734 if (TREE_CODE (op) != SSA_NAME)
4737 /* Build a vector of case labels sorted by destination label. */
4738 ci = XNEWVEC (struct case_info, n);
4739 for (idx = 0; idx < n; ++idx)
4741 ci[idx].expr = gimple_switch_label (last, idx);
4742 ci[idx].bb = label_to_block (CASE_LABEL (ci[idx].expr));
4744 qsort (ci, n, sizeof (struct case_info), compare_case_labels);
4746 for (idx = 0; idx < n; ++idx)
4749 tree cl = ci[idx].expr;
4750 basic_block cbb = ci[idx].bb;
4752 min = CASE_LOW (cl);
4753 max = CASE_HIGH (cl);
4755 /* If there are multiple case labels with the same destination
4756 we need to combine them to a single value range for the edge. */
4757 if (idx + 1 < n && cbb == ci[idx + 1].bb)
4759 /* Skip labels until the last of the group. */
4762 } while (idx < n && cbb == ci[idx].bb);
4765 /* Pick up the maximum of the case label range. */
4766 if (CASE_HIGH (ci[idx].expr))
4767 max = CASE_HIGH (ci[idx].expr);
4769 max = CASE_LOW (ci[idx].expr);
4772 /* Nothing to do if the range includes the default label until we
4773 can register anti-ranges. */
4774 if (min == NULL_TREE)
4777 /* Find the edge to register the assert expr on. */
4778 e = find_edge (bb, cbb);
4780 /* Register the necessary assertions for the operand in the
4782 need_assert |= register_edge_assert_for (op, e, bsi,
4783 max ? GE_EXPR : EQ_EXPR,
4785 fold_convert (TREE_TYPE (op),
4789 need_assert |= register_edge_assert_for (op, e, bsi, LE_EXPR,
4791 fold_convert (TREE_TYPE (op),
4801 /* Traverse all the statements in block BB looking for statements that
4802 may generate useful assertions for the SSA names in their operand.
4803 If a statement produces a useful assertion A for name N_i, then the
4804 list of assertions already generated for N_i is scanned to
4805 determine if A is actually needed.
4807 If N_i already had the assertion A at a location dominating the
4808 current location, then nothing needs to be done. Otherwise, the
4809 new location for A is recorded instead.
4811 1- For every statement S in BB, all the variables used by S are
4812 added to bitmap FOUND_IN_SUBGRAPH.
4814 2- If statement S uses an operand N in a way that exposes a known
4815 value range for N, then if N was not already generated by an
4816 ASSERT_EXPR, create a new assert location for N. For instance,
4817 if N is a pointer and the statement dereferences it, we can
4818 assume that N is not NULL.
4820 3- COND_EXPRs are a special case of #2. We can derive range
4821 information from the predicate but need to insert different
4822 ASSERT_EXPRs for each of the sub-graphs rooted at the
4823 conditional block. If the last statement of BB is a conditional
4824 expression of the form 'X op Y', then
4826 a) Remove X and Y from the set FOUND_IN_SUBGRAPH.
4828 b) If the conditional is the only entry point to the sub-graph
4829 corresponding to the THEN_CLAUSE, recurse into it. On
4830 return, if X and/or Y are marked in FOUND_IN_SUBGRAPH, then
4831 an ASSERT_EXPR is added for the corresponding variable.
4833 c) Repeat step (b) on the ELSE_CLAUSE.
4835 d) Mark X and Y in FOUND_IN_SUBGRAPH.
4844 In this case, an assertion on the THEN clause is useful to
4845 determine that 'a' is always 9 on that edge. However, an assertion
4846 on the ELSE clause would be unnecessary.
4848 4- If BB does not end in a conditional expression, then we recurse
4849 into BB's dominator children.
4851 At the end of the recursive traversal, every SSA name will have a
4852 list of locations where ASSERT_EXPRs should be added. When a new
4853 location for name N is found, it is registered by calling
4854 register_new_assert_for. That function keeps track of all the
4855 registered assertions to prevent adding unnecessary assertions.
4856 For instance, if a pointer P_4 is dereferenced more than once in a
4857 dominator tree, only the location dominating all the dereference of
4858 P_4 will receive an ASSERT_EXPR.
4860 If this function returns true, then it means that there are names
4861 for which we need to generate ASSERT_EXPRs. Those assertions are
4862 inserted by process_assert_insertions. */
4865 find_assert_locations_1 (basic_block bb, sbitmap live)
4867 gimple_stmt_iterator si;
4872 need_assert = false;
4873 last = last_stmt (bb);
4875 /* If BB's last statement is a conditional statement involving integer
4876 operands, determine if we need to add ASSERT_EXPRs. */
4878 && gimple_code (last) == GIMPLE_COND
4879 && !fp_predicate (last)
4880 && !ZERO_SSA_OPERANDS (last, SSA_OP_USE))
4881 need_assert |= find_conditional_asserts (bb, last);
4883 /* If BB's last statement is a switch statement involving integer
4884 operands, determine if we need to add ASSERT_EXPRs. */
4886 && gimple_code (last) == GIMPLE_SWITCH
4887 && !ZERO_SSA_OPERANDS (last, SSA_OP_USE))
4888 need_assert |= find_switch_asserts (bb, last);
4890 /* Traverse all the statements in BB marking used names and looking
4891 for statements that may infer assertions for their used operands. */
4892 for (si = gsi_start_bb (bb); !gsi_end_p (si); gsi_next (&si))
4898 stmt = gsi_stmt (si);
4900 if (is_gimple_debug (stmt))
4903 /* See if we can derive an assertion for any of STMT's operands. */
4904 FOR_EACH_SSA_TREE_OPERAND (op, stmt, i, SSA_OP_USE)
4907 enum tree_code comp_code;
4909 /* Mark OP in our live bitmap. */
4910 SET_BIT (live, SSA_NAME_VERSION (op));
4912 /* If OP is used in such a way that we can infer a value
4913 range for it, and we don't find a previous assertion for
4914 it, create a new assertion location node for OP. */
4915 if (infer_value_range (stmt, op, &comp_code, &value))
4917 /* If we are able to infer a nonzero value range for OP,
4918 then walk backwards through the use-def chain to see if OP
4919 was set via a typecast.
4921 If so, then we can also infer a nonzero value range
4922 for the operand of the NOP_EXPR. */
4923 if (comp_code == NE_EXPR && integer_zerop (value))
4926 gimple def_stmt = SSA_NAME_DEF_STMT (t);
4928 while (is_gimple_assign (def_stmt)
4929 && gimple_assign_rhs_code (def_stmt) == NOP_EXPR
4931 (gimple_assign_rhs1 (def_stmt)) == SSA_NAME
4933 (TREE_TYPE (gimple_assign_rhs1 (def_stmt))))
4935 t = gimple_assign_rhs1 (def_stmt);
4936 def_stmt = SSA_NAME_DEF_STMT (t);
4938 /* Note we want to register the assert for the
4939 operand of the NOP_EXPR after SI, not after the
4941 if (! has_single_use (t))
4943 register_new_assert_for (t, t, comp_code, value,
4950 /* If OP is used only once, namely in this STMT, don't
4951 bother creating an ASSERT_EXPR for it. Such an
4952 ASSERT_EXPR would do nothing but increase compile time. */
4953 if (!has_single_use (op))
4955 register_new_assert_for (op, op, comp_code, value,
4963 /* Traverse all PHI nodes in BB marking used operands. */
4964 for (si = gsi_start_phis (bb); !gsi_end_p(si); gsi_next (&si))
4966 use_operand_p arg_p;
4968 phi = gsi_stmt (si);
4970 FOR_EACH_PHI_ARG (arg_p, phi, i, SSA_OP_USE)
4972 tree arg = USE_FROM_PTR (arg_p);
4973 if (TREE_CODE (arg) == SSA_NAME)
4974 SET_BIT (live, SSA_NAME_VERSION (arg));
4981 /* Do an RPO walk over the function computing SSA name liveness
4982 on-the-fly and deciding on assert expressions to insert.
4983 Returns true if there are assert expressions to be inserted. */
4986 find_assert_locations (void)
4988 int *rpo = XCNEWVEC (int, last_basic_block + NUM_FIXED_BLOCKS);
4989 int *bb_rpo = XCNEWVEC (int, last_basic_block + NUM_FIXED_BLOCKS);
4990 int *last_rpo = XCNEWVEC (int, last_basic_block + NUM_FIXED_BLOCKS);
4994 live = XCNEWVEC (sbitmap, last_basic_block + NUM_FIXED_BLOCKS);
4995 rpo_cnt = pre_and_rev_post_order_compute (NULL, rpo, false);
4996 for (i = 0; i < rpo_cnt; ++i)
4999 need_asserts = false;
5000 for (i = rpo_cnt-1; i >= 0; --i)
5002 basic_block bb = BASIC_BLOCK (rpo[i]);
5008 live[rpo[i]] = sbitmap_alloc (num_ssa_names);
5009 sbitmap_zero (live[rpo[i]]);
5012 /* Process BB and update the live information with uses in
5014 need_asserts |= find_assert_locations_1 (bb, live[rpo[i]]);
5016 /* Merge liveness into the predecessor blocks and free it. */
5017 if (!sbitmap_empty_p (live[rpo[i]]))
5020 FOR_EACH_EDGE (e, ei, bb->preds)
5022 int pred = e->src->index;
5023 if (e->flags & EDGE_DFS_BACK)
5028 live[pred] = sbitmap_alloc (num_ssa_names);
5029 sbitmap_zero (live[pred]);
5031 sbitmap_a_or_b (live[pred], live[pred], live[rpo[i]]);
5033 if (bb_rpo[pred] < pred_rpo)
5034 pred_rpo = bb_rpo[pred];
5037 /* Record the RPO number of the last visited block that needs
5038 live information from this block. */
5039 last_rpo[rpo[i]] = pred_rpo;
5043 sbitmap_free (live[rpo[i]]);
5044 live[rpo[i]] = NULL;
5047 /* We can free all successors live bitmaps if all their
5048 predecessors have been visited already. */
5049 FOR_EACH_EDGE (e, ei, bb->succs)
5050 if (last_rpo[e->dest->index] == i
5051 && live[e->dest->index])
5053 sbitmap_free (live[e->dest->index]);
5054 live[e->dest->index] = NULL;
5059 XDELETEVEC (bb_rpo);
5060 XDELETEVEC (last_rpo);
5061 for (i = 0; i < last_basic_block + NUM_FIXED_BLOCKS; ++i)
5063 sbitmap_free (live[i]);
5066 return need_asserts;
5069 /* Create an ASSERT_EXPR for NAME and insert it in the location
5070 indicated by LOC. Return true if we made any edge insertions. */
5073 process_assert_insertions_for (tree name, assert_locus_t loc)
5075 /* Build the comparison expression NAME_i COMP_CODE VAL. */
5082 /* If we have X <=> X do not insert an assert expr for that. */
5083 if (loc->expr == loc->val)
5086 cond = build2 (loc->comp_code, boolean_type_node, loc->expr, loc->val);
5087 assert_stmt = build_assert_expr_for (cond, name);
5090 /* We have been asked to insert the assertion on an edge. This
5091 is used only by COND_EXPR and SWITCH_EXPR assertions. */
5092 gcc_checking_assert (gimple_code (gsi_stmt (loc->si)) == GIMPLE_COND
5093 || (gimple_code (gsi_stmt (loc->si))
5096 gsi_insert_on_edge (loc->e, assert_stmt);
5100 /* Otherwise, we can insert right after LOC->SI iff the
5101 statement must not be the last statement in the block. */
5102 stmt = gsi_stmt (loc->si);
5103 if (!stmt_ends_bb_p (stmt))
5105 gsi_insert_after (&loc->si, assert_stmt, GSI_SAME_STMT);
5109 /* If STMT must be the last statement in BB, we can only insert new
5110 assertions on the non-abnormal edge out of BB. Note that since
5111 STMT is not control flow, there may only be one non-abnormal edge
5113 FOR_EACH_EDGE (e, ei, loc->bb->succs)
5114 if (!(e->flags & EDGE_ABNORMAL))
5116 gsi_insert_on_edge (e, assert_stmt);
5124 /* Process all the insertions registered for every name N_i registered
5125 in NEED_ASSERT_FOR. The list of assertions to be inserted are
5126 found in ASSERTS_FOR[i]. */
5129 process_assert_insertions (void)
5133 bool update_edges_p = false;
5134 int num_asserts = 0;
5136 if (dump_file && (dump_flags & TDF_DETAILS))
5137 dump_all_asserts (dump_file);
5139 EXECUTE_IF_SET_IN_BITMAP (need_assert_for, 0, i, bi)
5141 assert_locus_t loc = asserts_for[i];
5146 assert_locus_t next = loc->next;
5147 update_edges_p |= process_assert_insertions_for (ssa_name (i), loc);
5155 gsi_commit_edge_inserts ();
5157 statistics_counter_event (cfun, "Number of ASSERT_EXPR expressions inserted",
5162 /* Traverse the flowgraph looking for conditional jumps to insert range
5163 expressions. These range expressions are meant to provide information
5164 to optimizations that need to reason in terms of value ranges. They
5165 will not be expanded into RTL. For instance, given:
5174 this pass will transform the code into:
5180 x = ASSERT_EXPR <x, x < y>
5185 y = ASSERT_EXPR <y, x <= y>
5189 The idea is that once copy and constant propagation have run, other
5190 optimizations will be able to determine what ranges of values can 'x'
5191 take in different paths of the code, simply by checking the reaching
5192 definition of 'x'. */
5195 insert_range_assertions (void)
5197 need_assert_for = BITMAP_ALLOC (NULL);
5198 asserts_for = XCNEWVEC (assert_locus_t, num_ssa_names);
5200 calculate_dominance_info (CDI_DOMINATORS);
5202 if (find_assert_locations ())
5204 process_assert_insertions ();
5205 update_ssa (TODO_update_ssa_no_phi);
5208 if (dump_file && (dump_flags & TDF_DETAILS))
5210 fprintf (dump_file, "\nSSA form after inserting ASSERT_EXPRs\n");
5211 dump_function_to_file (current_function_decl, dump_file, dump_flags);
5215 BITMAP_FREE (need_assert_for);
5218 /* Checks one ARRAY_REF in REF, located at LOCUS. Ignores flexible arrays
5219 and "struct" hacks. If VRP can determine that the
5220 array subscript is a constant, check if it is outside valid
5221 range. If the array subscript is a RANGE, warn if it is
5222 non-overlapping with valid range.
5223 IGNORE_OFF_BY_ONE is true if the ARRAY_REF is inside a ADDR_EXPR. */
5226 check_array_ref (location_t location, tree ref, bool ignore_off_by_one)
5228 value_range_t* vr = NULL;
5229 tree low_sub, up_sub;
5230 tree low_bound, up_bound, up_bound_p1;
5233 if (TREE_NO_WARNING (ref))
5236 low_sub = up_sub = TREE_OPERAND (ref, 1);
5237 up_bound = array_ref_up_bound (ref);
5239 /* Can not check flexible arrays. */
5241 || TREE_CODE (up_bound) != INTEGER_CST)
5244 /* Accesses to trailing arrays via pointers may access storage
5245 beyond the types array bounds. */
5246 base = get_base_address (ref);
5247 if (base && TREE_CODE (base) == MEM_REF)
5249 tree cref, next = NULL_TREE;
5251 if (TREE_CODE (TREE_OPERAND (ref, 0)) != COMPONENT_REF)
5254 cref = TREE_OPERAND (ref, 0);
5255 if (TREE_CODE (TREE_TYPE (TREE_OPERAND (cref, 0))) == RECORD_TYPE)
5256 for (next = DECL_CHAIN (TREE_OPERAND (cref, 1));
5257 next && TREE_CODE (next) != FIELD_DECL;
5258 next = DECL_CHAIN (next))
5261 /* If this is the last field in a struct type or a field in a
5262 union type do not warn. */
5267 low_bound = array_ref_low_bound (ref);
5268 up_bound_p1 = int_const_binop (PLUS_EXPR, up_bound, integer_one_node);
5270 if (TREE_CODE (low_sub) == SSA_NAME)
5272 vr = get_value_range (low_sub);
5273 if (vr->type == VR_RANGE || vr->type == VR_ANTI_RANGE)
5275 low_sub = vr->type == VR_RANGE ? vr->max : vr->min;
5276 up_sub = vr->type == VR_RANGE ? vr->min : vr->max;
5280 if (vr && vr->type == VR_ANTI_RANGE)
5282 if (TREE_CODE (up_sub) == INTEGER_CST
5283 && tree_int_cst_lt (up_bound, up_sub)
5284 && TREE_CODE (low_sub) == INTEGER_CST
5285 && tree_int_cst_lt (low_sub, low_bound))
5287 warning_at (location, OPT_Warray_bounds,
5288 "array subscript is outside array bounds");
5289 TREE_NO_WARNING (ref) = 1;
5292 else if (TREE_CODE (up_sub) == INTEGER_CST
5293 && (ignore_off_by_one
5294 ? (tree_int_cst_lt (up_bound, up_sub)
5295 && !tree_int_cst_equal (up_bound_p1, up_sub))
5296 : (tree_int_cst_lt (up_bound, up_sub)
5297 || tree_int_cst_equal (up_bound_p1, up_sub))))
5299 warning_at (location, OPT_Warray_bounds,
5300 "array subscript is above array bounds");
5301 TREE_NO_WARNING (ref) = 1;
5303 else if (TREE_CODE (low_sub) == INTEGER_CST
5304 && tree_int_cst_lt (low_sub, low_bound))
5306 warning_at (location, OPT_Warray_bounds,
5307 "array subscript is below array bounds");
5308 TREE_NO_WARNING (ref) = 1;
5312 /* Searches if the expr T, located at LOCATION computes
5313 address of an ARRAY_REF, and call check_array_ref on it. */
5316 search_for_addr_array (tree t, location_t location)
5318 while (TREE_CODE (t) == SSA_NAME)
5320 gimple g = SSA_NAME_DEF_STMT (t);
5322 if (gimple_code (g) != GIMPLE_ASSIGN)
5325 if (get_gimple_rhs_class (gimple_assign_rhs_code (g))
5326 != GIMPLE_SINGLE_RHS)
5329 t = gimple_assign_rhs1 (g);
5333 /* We are only interested in addresses of ARRAY_REF's. */
5334 if (TREE_CODE (t) != ADDR_EXPR)
5337 /* Check each ARRAY_REFs in the reference chain. */
5340 if (TREE_CODE (t) == ARRAY_REF)
5341 check_array_ref (location, t, true /*ignore_off_by_one*/);
5343 t = TREE_OPERAND (t, 0);
5345 while (handled_component_p (t));
5347 if (TREE_CODE (t) == MEM_REF
5348 && TREE_CODE (TREE_OPERAND (t, 0)) == ADDR_EXPR
5349 && !TREE_NO_WARNING (t))
5351 tree tem = TREE_OPERAND (TREE_OPERAND (t, 0), 0);
5352 tree low_bound, up_bound, el_sz;
5354 if (TREE_CODE (TREE_TYPE (tem)) != ARRAY_TYPE
5355 || TREE_CODE (TREE_TYPE (TREE_TYPE (tem))) == ARRAY_TYPE
5356 || !TYPE_DOMAIN (TREE_TYPE (tem)))
5359 low_bound = TYPE_MIN_VALUE (TYPE_DOMAIN (TREE_TYPE (tem)));
5360 up_bound = TYPE_MAX_VALUE (TYPE_DOMAIN (TREE_TYPE (tem)));
5361 el_sz = TYPE_SIZE_UNIT (TREE_TYPE (TREE_TYPE (tem)));
5363 || TREE_CODE (low_bound) != INTEGER_CST
5365 || TREE_CODE (up_bound) != INTEGER_CST
5367 || TREE_CODE (el_sz) != INTEGER_CST)
5370 idx = mem_ref_offset (t);
5371 idx = double_int_sdiv (idx, tree_to_double_int (el_sz), TRUNC_DIV_EXPR);
5372 if (double_int_scmp (idx, double_int_zero) < 0)
5374 warning_at (location, OPT_Warray_bounds,
5375 "array subscript is below array bounds");
5376 TREE_NO_WARNING (t) = 1;
5378 else if (double_int_scmp (idx,
5381 (tree_to_double_int (up_bound),
5383 (tree_to_double_int (low_bound))),
5384 double_int_one)) > 0)
5386 warning_at (location, OPT_Warray_bounds,
5387 "array subscript is above array bounds");
5388 TREE_NO_WARNING (t) = 1;
5393 /* walk_tree() callback that checks if *TP is
5394 an ARRAY_REF inside an ADDR_EXPR (in which an array
5395 subscript one outside the valid range is allowed). Call
5396 check_array_ref for each ARRAY_REF found. The location is
5400 check_array_bounds (tree *tp, int *walk_subtree, void *data)
5403 struct walk_stmt_info *wi = (struct walk_stmt_info *) data;
5404 location_t location;
5406 if (EXPR_HAS_LOCATION (t))
5407 location = EXPR_LOCATION (t);
5410 location_t *locp = (location_t *) wi->info;
5414 *walk_subtree = TRUE;
5416 if (TREE_CODE (t) == ARRAY_REF)
5417 check_array_ref (location, t, false /*ignore_off_by_one*/);
5419 if (TREE_CODE (t) == MEM_REF
5420 || (TREE_CODE (t) == RETURN_EXPR && TREE_OPERAND (t, 0)))
5421 search_for_addr_array (TREE_OPERAND (t, 0), location);
5423 if (TREE_CODE (t) == ADDR_EXPR)
5424 *walk_subtree = FALSE;
5429 /* Walk over all statements of all reachable BBs and call check_array_bounds
5433 check_all_array_refs (void)
5436 gimple_stmt_iterator si;
5442 bool executable = false;
5444 /* Skip blocks that were found to be unreachable. */
5445 FOR_EACH_EDGE (e, ei, bb->preds)
5446 executable |= !!(e->flags & EDGE_EXECUTABLE);
5450 for (si = gsi_start_bb (bb); !gsi_end_p (si); gsi_next (&si))
5452 gimple stmt = gsi_stmt (si);
5453 struct walk_stmt_info wi;
5454 if (!gimple_has_location (stmt))
5457 if (is_gimple_call (stmt))
5460 size_t n = gimple_call_num_args (stmt);
5461 for (i = 0; i < n; i++)
5463 tree arg = gimple_call_arg (stmt, i);
5464 search_for_addr_array (arg, gimple_location (stmt));
5469 memset (&wi, 0, sizeof (wi));
5470 wi.info = CONST_CAST (void *, (const void *)
5471 gimple_location_ptr (stmt));
5473 walk_gimple_op (gsi_stmt (si),
5481 /* Convert range assertion expressions into the implied copies and
5482 copy propagate away the copies. Doing the trivial copy propagation
5483 here avoids the need to run the full copy propagation pass after
5486 FIXME, this will eventually lead to copy propagation removing the
5487 names that had useful range information attached to them. For
5488 instance, if we had the assertion N_i = ASSERT_EXPR <N_j, N_j > 3>,
5489 then N_i will have the range [3, +INF].
5491 However, by converting the assertion into the implied copy
5492 operation N_i = N_j, we will then copy-propagate N_j into the uses
5493 of N_i and lose the range information. We may want to hold on to
5494 ASSERT_EXPRs a little while longer as the ranges could be used in
5495 things like jump threading.
5497 The problem with keeping ASSERT_EXPRs around is that passes after
5498 VRP need to handle them appropriately.
5500 Another approach would be to make the range information a first
5501 class property of the SSA_NAME so that it can be queried from
5502 any pass. This is made somewhat more complex by the need for
5503 multiple ranges to be associated with one SSA_NAME. */
5506 remove_range_assertions (void)
5509 gimple_stmt_iterator si;
5511 /* Note that the BSI iterator bump happens at the bottom of the
5512 loop and no bump is necessary if we're removing the statement
5513 referenced by the current BSI. */
5515 for (si = gsi_start_bb (bb); !gsi_end_p (si);)
5517 gimple stmt = gsi_stmt (si);
5520 if (is_gimple_assign (stmt)
5521 && gimple_assign_rhs_code (stmt) == ASSERT_EXPR)
5523 tree rhs = gimple_assign_rhs1 (stmt);
5525 tree cond = fold (ASSERT_EXPR_COND (rhs));
5526 use_operand_p use_p;
5527 imm_use_iterator iter;
5529 gcc_assert (cond != boolean_false_node);
5531 /* Propagate the RHS into every use of the LHS. */
5532 var = ASSERT_EXPR_VAR (rhs);
5533 FOR_EACH_IMM_USE_STMT (use_stmt, iter,
5534 gimple_assign_lhs (stmt))
5535 FOR_EACH_IMM_USE_ON_STMT (use_p, iter)
5537 SET_USE (use_p, var);
5538 gcc_assert (TREE_CODE (var) == SSA_NAME);
5541 /* And finally, remove the copy, it is not needed. */
5542 gsi_remove (&si, true);
5543 release_defs (stmt);
5551 /* Return true if STMT is interesting for VRP. */
5554 stmt_interesting_for_vrp (gimple stmt)
5556 if (gimple_code (stmt) == GIMPLE_PHI
5557 && is_gimple_reg (gimple_phi_result (stmt))
5558 && (INTEGRAL_TYPE_P (TREE_TYPE (gimple_phi_result (stmt)))
5559 || POINTER_TYPE_P (TREE_TYPE (gimple_phi_result (stmt)))))
5561 else if (is_gimple_assign (stmt) || is_gimple_call (stmt))
5563 tree lhs = gimple_get_lhs (stmt);
5565 /* In general, assignments with virtual operands are not useful
5566 for deriving ranges, with the obvious exception of calls to
5567 builtin functions. */
5568 if (lhs && TREE_CODE (lhs) == SSA_NAME
5569 && (INTEGRAL_TYPE_P (TREE_TYPE (lhs))
5570 || POINTER_TYPE_P (TREE_TYPE (lhs)))
5571 && ((is_gimple_call (stmt)
5572 && gimple_call_fndecl (stmt) != NULL_TREE
5573 && DECL_IS_BUILTIN (gimple_call_fndecl (stmt)))
5574 || !gimple_vuse (stmt)))
5577 else if (gimple_code (stmt) == GIMPLE_COND
5578 || gimple_code (stmt) == GIMPLE_SWITCH)
5585 /* Initialize local data structures for VRP. */
5588 vrp_initialize (void)
5592 values_propagated = false;
5593 num_vr_values = num_ssa_names;
5594 vr_value = XCNEWVEC (value_range_t *, num_vr_values);
5595 vr_phi_edge_counts = XCNEWVEC (int, num_ssa_names);
5599 gimple_stmt_iterator si;
5601 for (si = gsi_start_phis (bb); !gsi_end_p (si); gsi_next (&si))
5603 gimple phi = gsi_stmt (si);
5604 if (!stmt_interesting_for_vrp (phi))
5606 tree lhs = PHI_RESULT (phi);
5607 set_value_range_to_varying (get_value_range (lhs));
5608 prop_set_simulate_again (phi, false);
5611 prop_set_simulate_again (phi, true);
5614 for (si = gsi_start_bb (bb); !gsi_end_p (si); gsi_next (&si))
5616 gimple stmt = gsi_stmt (si);
5618 /* If the statement is a control insn, then we do not
5619 want to avoid simulating the statement once. Failure
5620 to do so means that those edges will never get added. */
5621 if (stmt_ends_bb_p (stmt))
5622 prop_set_simulate_again (stmt, true);
5623 else if (!stmt_interesting_for_vrp (stmt))
5627 FOR_EACH_SSA_TREE_OPERAND (def, stmt, i, SSA_OP_DEF)
5628 set_value_range_to_varying (get_value_range (def));
5629 prop_set_simulate_again (stmt, false);
5632 prop_set_simulate_again (stmt, true);
5637 /* Return the singleton value-range for NAME or NAME. */
5640 vrp_valueize (tree name)
5642 if (TREE_CODE (name) == SSA_NAME)
5644 value_range_t *vr = get_value_range (name);
5645 if (vr->type == VR_RANGE
5646 && (vr->min == vr->max
5647 || operand_equal_p (vr->min, vr->max, 0)))
5653 /* Visit assignment STMT. If it produces an interesting range, record
5654 the SSA name in *OUTPUT_P. */
5656 static enum ssa_prop_result
5657 vrp_visit_assignment_or_call (gimple stmt, tree *output_p)
5661 enum gimple_code code = gimple_code (stmt);
5662 lhs = gimple_get_lhs (stmt);
5664 /* We only keep track of ranges in integral and pointer types. */
5665 if (TREE_CODE (lhs) == SSA_NAME
5666 && ((INTEGRAL_TYPE_P (TREE_TYPE (lhs))
5667 /* It is valid to have NULL MIN/MAX values on a type. See
5668 build_range_type. */
5669 && TYPE_MIN_VALUE (TREE_TYPE (lhs))
5670 && TYPE_MAX_VALUE (TREE_TYPE (lhs)))
5671 || POINTER_TYPE_P (TREE_TYPE (lhs))))
5673 value_range_t new_vr = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
5675 /* Try folding the statement to a constant first. */
5676 tree tem = gimple_fold_stmt_to_constant (stmt, vrp_valueize);
5677 if (tem && !is_overflow_infinity (tem))
5678 set_value_range (&new_vr, VR_RANGE, tem, tem, NULL);
5679 /* Then dispatch to value-range extracting functions. */
5680 else if (code == GIMPLE_CALL)
5681 extract_range_basic (&new_vr, stmt);
5683 extract_range_from_assignment (&new_vr, stmt);
5685 if (update_value_range (lhs, &new_vr))
5689 if (dump_file && (dump_flags & TDF_DETAILS))
5691 fprintf (dump_file, "Found new range for ");
5692 print_generic_expr (dump_file, lhs, 0);
5693 fprintf (dump_file, ": ");
5694 dump_value_range (dump_file, &new_vr);
5695 fprintf (dump_file, "\n\n");
5698 if (new_vr.type == VR_VARYING)
5699 return SSA_PROP_VARYING;
5701 return SSA_PROP_INTERESTING;
5704 return SSA_PROP_NOT_INTERESTING;
5707 /* Every other statement produces no useful ranges. */
5708 FOR_EACH_SSA_TREE_OPERAND (def, stmt, iter, SSA_OP_DEF)
5709 set_value_range_to_varying (get_value_range (def));
5711 return SSA_PROP_VARYING;
5714 /* Helper that gets the value range of the SSA_NAME with version I
5715 or a symbolic range containing the SSA_NAME only if the value range
5716 is varying or undefined. */
5718 static inline value_range_t
5719 get_vr_for_comparison (int i)
5721 value_range_t vr = *get_value_range (ssa_name (i));
5723 /* If name N_i does not have a valid range, use N_i as its own
5724 range. This allows us to compare against names that may
5725 have N_i in their ranges. */
5726 if (vr.type == VR_VARYING || vr.type == VR_UNDEFINED)
5729 vr.min = ssa_name (i);
5730 vr.max = ssa_name (i);
5736 /* Compare all the value ranges for names equivalent to VAR with VAL
5737 using comparison code COMP. Return the same value returned by
5738 compare_range_with_value, including the setting of
5739 *STRICT_OVERFLOW_P. */
5742 compare_name_with_value (enum tree_code comp, tree var, tree val,
5743 bool *strict_overflow_p)
5749 int used_strict_overflow;
5751 value_range_t equiv_vr;
5753 /* Get the set of equivalences for VAR. */
5754 e = get_value_range (var)->equiv;
5756 /* Start at -1. Set it to 0 if we do a comparison without relying
5757 on overflow, or 1 if all comparisons rely on overflow. */
5758 used_strict_overflow = -1;
5760 /* Compare vars' value range with val. */
5761 equiv_vr = get_vr_for_comparison (SSA_NAME_VERSION (var));
5763 retval = compare_range_with_value (comp, &equiv_vr, val, &sop);
5765 used_strict_overflow = sop ? 1 : 0;
5767 /* If the equiv set is empty we have done all work we need to do. */
5771 && used_strict_overflow > 0)
5772 *strict_overflow_p = true;
5776 EXECUTE_IF_SET_IN_BITMAP (e, 0, i, bi)
5778 equiv_vr = get_vr_for_comparison (i);
5780 t = compare_range_with_value (comp, &equiv_vr, val, &sop);
5783 /* If we get different answers from different members
5784 of the equivalence set this check must be in a dead
5785 code region. Folding it to a trap representation
5786 would be correct here. For now just return don't-know. */
5796 used_strict_overflow = 0;
5797 else if (used_strict_overflow < 0)
5798 used_strict_overflow = 1;
5803 && used_strict_overflow > 0)
5804 *strict_overflow_p = true;
5810 /* Given a comparison code COMP and names N1 and N2, compare all the
5811 ranges equivalent to N1 against all the ranges equivalent to N2
5812 to determine the value of N1 COMP N2. Return the same value
5813 returned by compare_ranges. Set *STRICT_OVERFLOW_P to indicate
5814 whether we relied on an overflow infinity in the comparison. */
5818 compare_names (enum tree_code comp, tree n1, tree n2,
5819 bool *strict_overflow_p)
5823 bitmap_iterator bi1, bi2;
5825 int used_strict_overflow;
5826 static bitmap_obstack *s_obstack = NULL;
5827 static bitmap s_e1 = NULL, s_e2 = NULL;
5829 /* Compare the ranges of every name equivalent to N1 against the
5830 ranges of every name equivalent to N2. */
5831 e1 = get_value_range (n1)->equiv;
5832 e2 = get_value_range (n2)->equiv;
5834 /* Use the fake bitmaps if e1 or e2 are not available. */
5835 if (s_obstack == NULL)
5837 s_obstack = XNEW (bitmap_obstack);
5838 bitmap_obstack_initialize (s_obstack);
5839 s_e1 = BITMAP_ALLOC (s_obstack);
5840 s_e2 = BITMAP_ALLOC (s_obstack);
5847 /* Add N1 and N2 to their own set of equivalences to avoid
5848 duplicating the body of the loop just to check N1 and N2
5850 bitmap_set_bit (e1, SSA_NAME_VERSION (n1));
5851 bitmap_set_bit (e2, SSA_NAME_VERSION (n2));
5853 /* If the equivalence sets have a common intersection, then the two
5854 names can be compared without checking their ranges. */
5855 if (bitmap_intersect_p (e1, e2))
5857 bitmap_clear_bit (e1, SSA_NAME_VERSION (n1));
5858 bitmap_clear_bit (e2, SSA_NAME_VERSION (n2));
5860 return (comp == EQ_EXPR || comp == GE_EXPR || comp == LE_EXPR)
5862 : boolean_false_node;
5865 /* Start at -1. Set it to 0 if we do a comparison without relying
5866 on overflow, or 1 if all comparisons rely on overflow. */
5867 used_strict_overflow = -1;
5869 /* Otherwise, compare all the equivalent ranges. First, add N1 and
5870 N2 to their own set of equivalences to avoid duplicating the body
5871 of the loop just to check N1 and N2 ranges. */
5872 EXECUTE_IF_SET_IN_BITMAP (e1, 0, i1, bi1)
5874 value_range_t vr1 = get_vr_for_comparison (i1);
5876 t = retval = NULL_TREE;
5877 EXECUTE_IF_SET_IN_BITMAP (e2, 0, i2, bi2)
5881 value_range_t vr2 = get_vr_for_comparison (i2);
5883 t = compare_ranges (comp, &vr1, &vr2, &sop);
5886 /* If we get different answers from different members
5887 of the equivalence set this check must be in a dead
5888 code region. Folding it to a trap representation
5889 would be correct here. For now just return don't-know. */
5893 bitmap_clear_bit (e1, SSA_NAME_VERSION (n1));
5894 bitmap_clear_bit (e2, SSA_NAME_VERSION (n2));
5900 used_strict_overflow = 0;
5901 else if (used_strict_overflow < 0)
5902 used_strict_overflow = 1;
5908 bitmap_clear_bit (e1, SSA_NAME_VERSION (n1));
5909 bitmap_clear_bit (e2, SSA_NAME_VERSION (n2));
5910 if (used_strict_overflow > 0)
5911 *strict_overflow_p = true;
5916 /* None of the equivalent ranges are useful in computing this
5918 bitmap_clear_bit (e1, SSA_NAME_VERSION (n1));
5919 bitmap_clear_bit (e2, SSA_NAME_VERSION (n2));
5923 /* Helper function for vrp_evaluate_conditional_warnv. */
5926 vrp_evaluate_conditional_warnv_with_ops_using_ranges (enum tree_code code,
5928 bool * strict_overflow_p)
5930 value_range_t *vr0, *vr1;
5932 vr0 = (TREE_CODE (op0) == SSA_NAME) ? get_value_range (op0) : NULL;
5933 vr1 = (TREE_CODE (op1) == SSA_NAME) ? get_value_range (op1) : NULL;
5936 return compare_ranges (code, vr0, vr1, strict_overflow_p);
5937 else if (vr0 && vr1 == NULL)
5938 return compare_range_with_value (code, vr0, op1, strict_overflow_p);
5939 else if (vr0 == NULL && vr1)
5940 return (compare_range_with_value
5941 (swap_tree_comparison (code), vr1, op0, strict_overflow_p));
5945 /* Helper function for vrp_evaluate_conditional_warnv. */
5948 vrp_evaluate_conditional_warnv_with_ops (enum tree_code code, tree op0,
5949 tree op1, bool use_equiv_p,
5950 bool *strict_overflow_p, bool *only_ranges)
5954 *only_ranges = true;
5956 /* We only deal with integral and pointer types. */
5957 if (!INTEGRAL_TYPE_P (TREE_TYPE (op0))
5958 && !POINTER_TYPE_P (TREE_TYPE (op0)))
5964 && (ret = vrp_evaluate_conditional_warnv_with_ops_using_ranges
5965 (code, op0, op1, strict_overflow_p)))
5967 *only_ranges = false;
5968 if (TREE_CODE (op0) == SSA_NAME && TREE_CODE (op1) == SSA_NAME)
5969 return compare_names (code, op0, op1, strict_overflow_p);
5970 else if (TREE_CODE (op0) == SSA_NAME)
5971 return compare_name_with_value (code, op0, op1, strict_overflow_p);
5972 else if (TREE_CODE (op1) == SSA_NAME)
5973 return (compare_name_with_value
5974 (swap_tree_comparison (code), op1, op0, strict_overflow_p));
5977 return vrp_evaluate_conditional_warnv_with_ops_using_ranges (code, op0, op1,
5982 /* Given (CODE OP0 OP1) within STMT, try to simplify it based on value range
5983 information. Return NULL if the conditional can not be evaluated.
5984 The ranges of all the names equivalent with the operands in COND
5985 will be used when trying to compute the value. If the result is
5986 based on undefined signed overflow, issue a warning if
5990 vrp_evaluate_conditional (enum tree_code code, tree op0, tree op1, gimple stmt)
5996 /* Some passes and foldings leak constants with overflow flag set
5997 into the IL. Avoid doing wrong things with these and bail out. */
5998 if ((TREE_CODE (op0) == INTEGER_CST
5999 && TREE_OVERFLOW (op0))
6000 || (TREE_CODE (op1) == INTEGER_CST
6001 && TREE_OVERFLOW (op1)))
6005 ret = vrp_evaluate_conditional_warnv_with_ops (code, op0, op1, true, &sop,
6010 enum warn_strict_overflow_code wc;
6011 const char* warnmsg;
6013 if (is_gimple_min_invariant (ret))
6015 wc = WARN_STRICT_OVERFLOW_CONDITIONAL;
6016 warnmsg = G_("assuming signed overflow does not occur when "
6017 "simplifying conditional to constant");
6021 wc = WARN_STRICT_OVERFLOW_COMPARISON;
6022 warnmsg = G_("assuming signed overflow does not occur when "
6023 "simplifying conditional");
6026 if (issue_strict_overflow_warning (wc))
6028 location_t location;
6030 if (!gimple_has_location (stmt))
6031 location = input_location;
6033 location = gimple_location (stmt);
6034 warning_at (location, OPT_Wstrict_overflow, "%s", warnmsg);
6038 if (warn_type_limits
6039 && ret && only_ranges
6040 && TREE_CODE_CLASS (code) == tcc_comparison
6041 && TREE_CODE (op0) == SSA_NAME)
6043 /* If the comparison is being folded and the operand on the LHS
6044 is being compared against a constant value that is outside of
6045 the natural range of OP0's type, then the predicate will
6046 always fold regardless of the value of OP0. If -Wtype-limits
6047 was specified, emit a warning. */
6048 tree type = TREE_TYPE (op0);
6049 value_range_t *vr0 = get_value_range (op0);
6051 if (vr0->type != VR_VARYING
6052 && INTEGRAL_TYPE_P (type)
6053 && vrp_val_is_min (vr0->min)
6054 && vrp_val_is_max (vr0->max)
6055 && is_gimple_min_invariant (op1))
6057 location_t location;
6059 if (!gimple_has_location (stmt))
6060 location = input_location;
6062 location = gimple_location (stmt);
6064 warning_at (location, OPT_Wtype_limits,
6066 ? G_("comparison always false "
6067 "due to limited range of data type")
6068 : G_("comparison always true "
6069 "due to limited range of data type"));
6077 /* Visit conditional statement STMT. If we can determine which edge
6078 will be taken out of STMT's basic block, record it in
6079 *TAKEN_EDGE_P and return SSA_PROP_INTERESTING. Otherwise, return
6080 SSA_PROP_VARYING. */
6082 static enum ssa_prop_result
6083 vrp_visit_cond_stmt (gimple stmt, edge *taken_edge_p)
6088 *taken_edge_p = NULL;
6090 if (dump_file && (dump_flags & TDF_DETAILS))
6095 fprintf (dump_file, "\nVisiting conditional with predicate: ");
6096 print_gimple_stmt (dump_file, stmt, 0, 0);
6097 fprintf (dump_file, "\nWith known ranges\n");
6099 FOR_EACH_SSA_TREE_OPERAND (use, stmt, i, SSA_OP_USE)
6101 fprintf (dump_file, "\t");
6102 print_generic_expr (dump_file, use, 0);
6103 fprintf (dump_file, ": ");
6104 dump_value_range (dump_file, vr_value[SSA_NAME_VERSION (use)]);
6107 fprintf (dump_file, "\n");
6110 /* Compute the value of the predicate COND by checking the known
6111 ranges of each of its operands.
6113 Note that we cannot evaluate all the equivalent ranges here
6114 because those ranges may not yet be final and with the current
6115 propagation strategy, we cannot determine when the value ranges
6116 of the names in the equivalence set have changed.
6118 For instance, given the following code fragment
6122 i_14 = ASSERT_EXPR <i_5, i_5 != 0>
6126 Assume that on the first visit to i_14, i_5 has the temporary
6127 range [8, 8] because the second argument to the PHI function is
6128 not yet executable. We derive the range ~[0, 0] for i_14 and the
6129 equivalence set { i_5 }. So, when we visit 'if (i_14 == 1)' for
6130 the first time, since i_14 is equivalent to the range [8, 8], we
6131 determine that the predicate is always false.
6133 On the next round of propagation, i_13 is determined to be
6134 VARYING, which causes i_5 to drop down to VARYING. So, another
6135 visit to i_14 is scheduled. In this second visit, we compute the
6136 exact same range and equivalence set for i_14, namely ~[0, 0] and
6137 { i_5 }. But we did not have the previous range for i_5
6138 registered, so vrp_visit_assignment thinks that the range for
6139 i_14 has not changed. Therefore, the predicate 'if (i_14 == 1)'
6140 is not visited again, which stops propagation from visiting
6141 statements in the THEN clause of that if().
6143 To properly fix this we would need to keep the previous range
6144 value for the names in the equivalence set. This way we would've
6145 discovered that from one visit to the other i_5 changed from
6146 range [8, 8] to VR_VARYING.
6148 However, fixing this apparent limitation may not be worth the
6149 additional checking. Testing on several code bases (GCC, DLV,
6150 MICO, TRAMP3D and SPEC2000) showed that doing this results in
6151 4 more predicates folded in SPEC. */
6154 val = vrp_evaluate_conditional_warnv_with_ops (gimple_cond_code (stmt),
6155 gimple_cond_lhs (stmt),
6156 gimple_cond_rhs (stmt),
6161 *taken_edge_p = find_taken_edge (gimple_bb (stmt), val);
6164 if (dump_file && (dump_flags & TDF_DETAILS))
6166 "\nIgnoring predicate evaluation because "
6167 "it assumes that signed overflow is undefined");
6172 if (dump_file && (dump_flags & TDF_DETAILS))
6174 fprintf (dump_file, "\nPredicate evaluates to: ");
6175 if (val == NULL_TREE)
6176 fprintf (dump_file, "DON'T KNOW\n");
6178 print_generic_stmt (dump_file, val, 0);
6181 return (*taken_edge_p) ? SSA_PROP_INTERESTING : SSA_PROP_VARYING;
6184 /* Searches the case label vector VEC for the index *IDX of the CASE_LABEL
6185 that includes the value VAL. The search is restricted to the range
6186 [START_IDX, n - 1] where n is the size of VEC.
6188 If there is a CASE_LABEL for VAL, its index is placed in IDX and true is
6191 If there is no CASE_LABEL for VAL and there is one that is larger than VAL,
6192 it is placed in IDX and false is returned.
6194 If VAL is larger than any CASE_LABEL, n is placed on IDX and false is
6198 find_case_label_index (gimple stmt, size_t start_idx, tree val, size_t *idx)
6200 size_t n = gimple_switch_num_labels (stmt);
6203 /* Find case label for minimum of the value range or the next one.
6204 At each iteration we are searching in [low, high - 1]. */
6206 for (low = start_idx, high = n; high != low; )
6210 /* Note that i != high, so we never ask for n. */
6211 size_t i = (high + low) / 2;
6212 t = gimple_switch_label (stmt, i);
6214 /* Cache the result of comparing CASE_LOW and val. */
6215 cmp = tree_int_cst_compare (CASE_LOW (t), val);
6219 /* Ranges cannot be empty. */
6228 if (CASE_HIGH (t) != NULL
6229 && tree_int_cst_compare (CASE_HIGH (t), val) >= 0)
6241 /* Searches the case label vector VEC for the range of CASE_LABELs that is used
6242 for values between MIN and MAX. The first index is placed in MIN_IDX. The
6243 last index is placed in MAX_IDX. If the range of CASE_LABELs is empty
6244 then MAX_IDX < MIN_IDX.
6245 Returns true if the default label is not needed. */
6248 find_case_label_range (gimple stmt, tree min, tree max, size_t *min_idx,
6252 bool min_take_default = !find_case_label_index (stmt, 1, min, &i);
6253 bool max_take_default = !find_case_label_index (stmt, i, max, &j);
6257 && max_take_default)
6259 /* Only the default case label reached.
6260 Return an empty range. */
6267 bool take_default = min_take_default || max_take_default;
6271 if (max_take_default)
6274 /* If the case label range is continuous, we do not need
6275 the default case label. Verify that. */
6276 high = CASE_LOW (gimple_switch_label (stmt, i));
6277 if (CASE_HIGH (gimple_switch_label (stmt, i)))
6278 high = CASE_HIGH (gimple_switch_label (stmt, i));
6279 for (k = i + 1; k <= j; ++k)
6281 low = CASE_LOW (gimple_switch_label (stmt, k));
6282 if (!integer_onep (int_const_binop (MINUS_EXPR, low, high)))
6284 take_default = true;
6288 if (CASE_HIGH (gimple_switch_label (stmt, k)))
6289 high = CASE_HIGH (gimple_switch_label (stmt, k));
6294 return !take_default;
6298 /* Visit switch statement STMT. If we can determine which edge
6299 will be taken out of STMT's basic block, record it in
6300 *TAKEN_EDGE_P and return SSA_PROP_INTERESTING. Otherwise, return
6301 SSA_PROP_VARYING. */
6303 static enum ssa_prop_result
6304 vrp_visit_switch_stmt (gimple stmt, edge *taken_edge_p)
6308 size_t i = 0, j = 0;
6311 *taken_edge_p = NULL;
6312 op = gimple_switch_index (stmt);
6313 if (TREE_CODE (op) != SSA_NAME)
6314 return SSA_PROP_VARYING;
6316 vr = get_value_range (op);
6317 if (dump_file && (dump_flags & TDF_DETAILS))
6319 fprintf (dump_file, "\nVisiting switch expression with operand ");
6320 print_generic_expr (dump_file, op, 0);
6321 fprintf (dump_file, " with known range ");
6322 dump_value_range (dump_file, vr);
6323 fprintf (dump_file, "\n");
6326 if (vr->type != VR_RANGE
6327 || symbolic_range_p (vr))
6328 return SSA_PROP_VARYING;
6330 /* Find the single edge that is taken from the switch expression. */
6331 take_default = !find_case_label_range (stmt, vr->min, vr->max, &i, &j);
6333 /* Check if the range spans no CASE_LABEL. If so, we only reach the default
6337 gcc_assert (take_default);
6338 val = gimple_switch_default_label (stmt);
6342 /* Check if labels with index i to j and maybe the default label
6343 are all reaching the same label. */
6345 val = gimple_switch_label (stmt, i);
6347 && CASE_LABEL (gimple_switch_default_label (stmt))
6348 != CASE_LABEL (val))
6350 if (dump_file && (dump_flags & TDF_DETAILS))
6351 fprintf (dump_file, " not a single destination for this "
6353 return SSA_PROP_VARYING;
6355 for (++i; i <= j; ++i)
6357 if (CASE_LABEL (gimple_switch_label (stmt, i)) != CASE_LABEL (val))
6359 if (dump_file && (dump_flags & TDF_DETAILS))
6360 fprintf (dump_file, " not a single destination for this "
6362 return SSA_PROP_VARYING;
6367 *taken_edge_p = find_edge (gimple_bb (stmt),
6368 label_to_block (CASE_LABEL (val)));
6370 if (dump_file && (dump_flags & TDF_DETAILS))
6372 fprintf (dump_file, " will take edge to ");
6373 print_generic_stmt (dump_file, CASE_LABEL (val), 0);
6376 return SSA_PROP_INTERESTING;
6380 /* Evaluate statement STMT. If the statement produces a useful range,
6381 return SSA_PROP_INTERESTING and record the SSA name with the
6382 interesting range into *OUTPUT_P.
6384 If STMT is a conditional branch and we can determine its truth
6385 value, the taken edge is recorded in *TAKEN_EDGE_P.
6387 If STMT produces a varying value, return SSA_PROP_VARYING. */
6389 static enum ssa_prop_result
6390 vrp_visit_stmt (gimple stmt, edge *taken_edge_p, tree *output_p)
6395 if (dump_file && (dump_flags & TDF_DETAILS))
6397 fprintf (dump_file, "\nVisiting statement:\n");
6398 print_gimple_stmt (dump_file, stmt, 0, dump_flags);
6399 fprintf (dump_file, "\n");
6402 if (!stmt_interesting_for_vrp (stmt))
6403 gcc_assert (stmt_ends_bb_p (stmt));
6404 else if (is_gimple_assign (stmt) || is_gimple_call (stmt))
6406 /* In general, assignments with virtual operands are not useful
6407 for deriving ranges, with the obvious exception of calls to
6408 builtin functions. */
6409 if ((is_gimple_call (stmt)
6410 && gimple_call_fndecl (stmt) != NULL_TREE
6411 && DECL_IS_BUILTIN (gimple_call_fndecl (stmt)))
6412 || !gimple_vuse (stmt))
6413 return vrp_visit_assignment_or_call (stmt, output_p);
6415 else if (gimple_code (stmt) == GIMPLE_COND)
6416 return vrp_visit_cond_stmt (stmt, taken_edge_p);
6417 else if (gimple_code (stmt) == GIMPLE_SWITCH)
6418 return vrp_visit_switch_stmt (stmt, taken_edge_p);
6420 /* All other statements produce nothing of interest for VRP, so mark
6421 their outputs varying and prevent further simulation. */
6422 FOR_EACH_SSA_TREE_OPERAND (def, stmt, iter, SSA_OP_DEF)
6423 set_value_range_to_varying (get_value_range (def));
6425 return SSA_PROP_VARYING;
6429 /* Meet operation for value ranges. Given two value ranges VR0 and
6430 VR1, store in VR0 a range that contains both VR0 and VR1. This
6431 may not be the smallest possible such range. */
6434 vrp_meet (value_range_t *vr0, value_range_t *vr1)
6436 if (vr0->type == VR_UNDEFINED)
6438 copy_value_range (vr0, vr1);
6442 if (vr1->type == VR_UNDEFINED)
6444 /* Nothing to do. VR0 already has the resulting range. */
6448 if (vr0->type == VR_VARYING)
6450 /* Nothing to do. VR0 already has the resulting range. */
6454 if (vr1->type == VR_VARYING)
6456 set_value_range_to_varying (vr0);
6460 if (vr0->type == VR_RANGE && vr1->type == VR_RANGE)
6465 /* Compute the convex hull of the ranges. The lower limit of
6466 the new range is the minimum of the two ranges. If they
6467 cannot be compared, then give up. */
6468 cmp = compare_values (vr0->min, vr1->min);
6469 if (cmp == 0 || cmp == 1)
6476 /* Similarly, the upper limit of the new range is the maximum
6477 of the two ranges. If they cannot be compared, then
6479 cmp = compare_values (vr0->max, vr1->max);
6480 if (cmp == 0 || cmp == -1)
6487 /* Check for useless ranges. */
6488 if (INTEGRAL_TYPE_P (TREE_TYPE (min))
6489 && ((vrp_val_is_min (min) || is_overflow_infinity (min))
6490 && (vrp_val_is_max (max) || is_overflow_infinity (max))))
6493 /* The resulting set of equivalences is the intersection of
6495 if (vr0->equiv && vr1->equiv && vr0->equiv != vr1->equiv)
6496 bitmap_and_into (vr0->equiv, vr1->equiv);
6497 else if (vr0->equiv && !vr1->equiv)
6498 bitmap_clear (vr0->equiv);
6500 set_value_range (vr0, vr0->type, min, max, vr0->equiv);
6502 else if (vr0->type == VR_ANTI_RANGE && vr1->type == VR_ANTI_RANGE)
6504 /* Two anti-ranges meet only if their complements intersect.
6505 Only handle the case of identical ranges. */
6506 if (compare_values (vr0->min, vr1->min) == 0
6507 && compare_values (vr0->max, vr1->max) == 0
6508 && compare_values (vr0->min, vr0->max) == 0)
6510 /* The resulting set of equivalences is the intersection of
6512 if (vr0->equiv && vr1->equiv && vr0->equiv != vr1->equiv)
6513 bitmap_and_into (vr0->equiv, vr1->equiv);
6514 else if (vr0->equiv && !vr1->equiv)
6515 bitmap_clear (vr0->equiv);
6520 else if (vr0->type == VR_ANTI_RANGE || vr1->type == VR_ANTI_RANGE)
6522 /* For a numeric range [VAL1, VAL2] and an anti-range ~[VAL3, VAL4],
6523 only handle the case where the ranges have an empty intersection.
6524 The result of the meet operation is the anti-range. */
6525 if (!symbolic_range_p (vr0)
6526 && !symbolic_range_p (vr1)
6527 && !value_ranges_intersect_p (vr0, vr1))
6529 /* Copy most of VR1 into VR0. Don't copy VR1's equivalence
6530 set. We need to compute the intersection of the two
6531 equivalence sets. */
6532 if (vr1->type == VR_ANTI_RANGE)
6533 set_value_range (vr0, vr1->type, vr1->min, vr1->max, vr0->equiv);
6535 /* The resulting set of equivalences is the intersection of
6537 if (vr0->equiv && vr1->equiv && vr0->equiv != vr1->equiv)
6538 bitmap_and_into (vr0->equiv, vr1->equiv);
6539 else if (vr0->equiv && !vr1->equiv)
6540 bitmap_clear (vr0->equiv);
6551 /* Failed to find an efficient meet. Before giving up and setting
6552 the result to VARYING, see if we can at least derive a useful
6553 anti-range. FIXME, all this nonsense about distinguishing
6554 anti-ranges from ranges is necessary because of the odd
6555 semantics of range_includes_zero_p and friends. */
6556 if (!symbolic_range_p (vr0)
6557 && ((vr0->type == VR_RANGE && !range_includes_zero_p (vr0))
6558 || (vr0->type == VR_ANTI_RANGE && range_includes_zero_p (vr0)))
6559 && !symbolic_range_p (vr1)
6560 && ((vr1->type == VR_RANGE && !range_includes_zero_p (vr1))
6561 || (vr1->type == VR_ANTI_RANGE && range_includes_zero_p (vr1))))
6563 set_value_range_to_nonnull (vr0, TREE_TYPE (vr0->min));
6565 /* Since this meet operation did not result from the meeting of
6566 two equivalent names, VR0 cannot have any equivalences. */
6568 bitmap_clear (vr0->equiv);
6571 set_value_range_to_varying (vr0);
6575 /* Visit all arguments for PHI node PHI that flow through executable
6576 edges. If a valid value range can be derived from all the incoming
6577 value ranges, set a new range for the LHS of PHI. */
6579 static enum ssa_prop_result
6580 vrp_visit_phi_node (gimple phi)
6583 tree lhs = PHI_RESULT (phi);
6584 value_range_t *lhs_vr = get_value_range (lhs);
6585 value_range_t vr_result = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
6586 int edges, old_edges;
6589 if (dump_file && (dump_flags & TDF_DETAILS))
6591 fprintf (dump_file, "\nVisiting PHI node: ");
6592 print_gimple_stmt (dump_file, phi, 0, dump_flags);
6596 for (i = 0; i < gimple_phi_num_args (phi); i++)
6598 edge e = gimple_phi_arg_edge (phi, i);
6600 if (dump_file && (dump_flags & TDF_DETAILS))
6603 "\n Argument #%d (%d -> %d %sexecutable)\n",
6604 (int) i, e->src->index, e->dest->index,
6605 (e->flags & EDGE_EXECUTABLE) ? "" : "not ");
6608 if (e->flags & EDGE_EXECUTABLE)
6610 tree arg = PHI_ARG_DEF (phi, i);
6611 value_range_t vr_arg;
6615 if (TREE_CODE (arg) == SSA_NAME)
6617 vr_arg = *(get_value_range (arg));
6621 if (is_overflow_infinity (arg))
6623 arg = copy_node (arg);
6624 TREE_OVERFLOW (arg) = 0;
6627 vr_arg.type = VR_RANGE;
6630 vr_arg.equiv = NULL;
6633 if (dump_file && (dump_flags & TDF_DETAILS))
6635 fprintf (dump_file, "\t");
6636 print_generic_expr (dump_file, arg, dump_flags);
6637 fprintf (dump_file, "\n\tValue: ");
6638 dump_value_range (dump_file, &vr_arg);
6639 fprintf (dump_file, "\n");
6642 vrp_meet (&vr_result, &vr_arg);
6644 if (vr_result.type == VR_VARYING)
6649 if (vr_result.type == VR_VARYING)
6652 old_edges = vr_phi_edge_counts[SSA_NAME_VERSION (lhs)];
6653 vr_phi_edge_counts[SSA_NAME_VERSION (lhs)] = edges;
6655 /* To prevent infinite iterations in the algorithm, derive ranges
6656 when the new value is slightly bigger or smaller than the
6657 previous one. We don't do this if we have seen a new executable
6658 edge; this helps us avoid an overflow infinity for conditionals
6659 which are not in a loop. */
6661 && gimple_phi_num_args (phi) > 1
6662 && edges == old_edges)
6664 int cmp_min = compare_values (lhs_vr->min, vr_result.min);
6665 int cmp_max = compare_values (lhs_vr->max, vr_result.max);
6667 /* For non VR_RANGE or for pointers fall back to varying if
6668 the range changed. */
6669 if ((lhs_vr->type != VR_RANGE || vr_result.type != VR_RANGE
6670 || POINTER_TYPE_P (TREE_TYPE (lhs)))
6671 && (cmp_min != 0 || cmp_max != 0))
6674 /* If the new minimum is smaller or larger than the previous
6675 one, go all the way to -INF. In the first case, to avoid
6676 iterating millions of times to reach -INF, and in the
6677 other case to avoid infinite bouncing between different
6679 if (cmp_min > 0 || cmp_min < 0)
6681 if (!needs_overflow_infinity (TREE_TYPE (vr_result.min))
6682 || !vrp_var_may_overflow (lhs, phi))
6683 vr_result.min = TYPE_MIN_VALUE (TREE_TYPE (vr_result.min));
6684 else if (supports_overflow_infinity (TREE_TYPE (vr_result.min)))
6686 negative_overflow_infinity (TREE_TYPE (vr_result.min));
6689 /* Similarly, if the new maximum is smaller or larger than
6690 the previous one, go all the way to +INF. */
6691 if (cmp_max < 0 || cmp_max > 0)
6693 if (!needs_overflow_infinity (TREE_TYPE (vr_result.max))
6694 || !vrp_var_may_overflow (lhs, phi))
6695 vr_result.max = TYPE_MAX_VALUE (TREE_TYPE (vr_result.max));
6696 else if (supports_overflow_infinity (TREE_TYPE (vr_result.max)))
6698 positive_overflow_infinity (TREE_TYPE (vr_result.max));
6701 /* If we dropped either bound to +-INF then if this is a loop
6702 PHI node SCEV may known more about its value-range. */
6703 if ((cmp_min > 0 || cmp_min < 0
6704 || cmp_max < 0 || cmp_max > 0)
6706 && (l = loop_containing_stmt (phi))
6707 && l->header == gimple_bb (phi))
6708 adjust_range_with_scev (&vr_result, l, phi, lhs);
6710 /* If we will end up with a (-INF, +INF) range, set it to
6711 VARYING. Same if the previous max value was invalid for
6712 the type and we end up with vr_result.min > vr_result.max. */
6713 if ((vrp_val_is_max (vr_result.max)
6714 && vrp_val_is_min (vr_result.min))
6715 || compare_values (vr_result.min,
6720 /* If the new range is different than the previous value, keep
6722 if (update_value_range (lhs, &vr_result))
6724 if (dump_file && (dump_flags & TDF_DETAILS))
6726 fprintf (dump_file, "Found new range for ");
6727 print_generic_expr (dump_file, lhs, 0);
6728 fprintf (dump_file, ": ");
6729 dump_value_range (dump_file, &vr_result);
6730 fprintf (dump_file, "\n\n");
6733 return SSA_PROP_INTERESTING;
6736 /* Nothing changed, don't add outgoing edges. */
6737 return SSA_PROP_NOT_INTERESTING;
6739 /* No match found. Set the LHS to VARYING. */
6741 set_value_range_to_varying (lhs_vr);
6742 return SSA_PROP_VARYING;
6745 /* Simplify boolean operations if the source is known
6746 to be already a boolean. */
6748 simplify_truth_ops_using_ranges (gimple_stmt_iterator *gsi, gimple stmt)
6750 enum tree_code rhs_code = gimple_assign_rhs_code (stmt);
6755 bool need_conversion;
6757 op0 = gimple_assign_rhs1 (stmt);
6758 if (TYPE_PRECISION (TREE_TYPE (op0)) != 1)
6760 if (TREE_CODE (op0) != SSA_NAME)
6762 vr = get_value_range (op0);
6764 val = compare_range_with_value (GE_EXPR, vr, integer_zero_node, &sop);
6765 if (!val || !integer_onep (val))
6768 val = compare_range_with_value (LE_EXPR, vr, integer_one_node, &sop);
6769 if (!val || !integer_onep (val))
6773 if (rhs_code == TRUTH_NOT_EXPR)
6776 op1 = build_int_cst (TREE_TYPE (op0), 1);
6780 op1 = gimple_assign_rhs2 (stmt);
6782 /* Reduce number of cases to handle. */
6783 if (is_gimple_min_invariant (op1))
6785 /* Exclude anything that should have been already folded. */
6786 if (rhs_code != EQ_EXPR
6787 && rhs_code != NE_EXPR)
6790 if (!integer_zerop (op1)
6791 && !integer_onep (op1)
6792 && !integer_all_onesp (op1))
6795 /* Limit the number of cases we have to consider. */
6796 if (rhs_code == EQ_EXPR)
6799 op1 = fold_unary (TRUTH_NOT_EXPR, TREE_TYPE (op1), op1);
6804 /* Punt on A == B as there is no BIT_XNOR_EXPR. */
6805 if (rhs_code == EQ_EXPR)
6808 if (TYPE_PRECISION (TREE_TYPE (op1)) != 1)
6810 vr = get_value_range (op1);
6811 val = compare_range_with_value (GE_EXPR, vr, integer_zero_node, &sop);
6812 if (!val || !integer_onep (val))
6815 val = compare_range_with_value (LE_EXPR, vr, integer_one_node, &sop);
6816 if (!val || !integer_onep (val))
6822 if (sop && issue_strict_overflow_warning (WARN_STRICT_OVERFLOW_MISC))
6824 location_t location;
6826 if (!gimple_has_location (stmt))
6827 location = input_location;
6829 location = gimple_location (stmt);
6831 warning_at (location, OPT_Wstrict_overflow,
6832 _("assuming signed overflow does not occur when "
6833 "simplifying ==, != or ! to identity or ^"));
6837 !useless_type_conversion_p (TREE_TYPE (gimple_assign_lhs (stmt)),
6840 /* Make sure to not sign-extend -1 as a boolean value. */
6842 && !TYPE_UNSIGNED (TREE_TYPE (op0))
6843 && TYPE_PRECISION (TREE_TYPE (op0)) == 1)
6849 if (integer_zerop (op1))
6851 gimple_assign_set_rhs_with_ops (gsi,
6852 need_conversion ? NOP_EXPR : SSA_NAME,
6854 update_stmt (gsi_stmt (*gsi));
6858 rhs_code = BIT_XOR_EXPR;
6864 if (need_conversion)
6867 gimple_assign_set_rhs_with_ops (gsi, rhs_code, op0, op1);
6868 update_stmt (gsi_stmt (*gsi));
6872 /* Simplify a division or modulo operator to a right shift or
6873 bitwise and if the first operand is unsigned or is greater
6874 than zero and the second operand is an exact power of two. */
6877 simplify_div_or_mod_using_ranges (gimple stmt)
6879 enum tree_code rhs_code = gimple_assign_rhs_code (stmt);
6881 tree op0 = gimple_assign_rhs1 (stmt);
6882 tree op1 = gimple_assign_rhs2 (stmt);
6883 value_range_t *vr = get_value_range (gimple_assign_rhs1 (stmt));
6885 if (TYPE_UNSIGNED (TREE_TYPE (op0)))
6887 val = integer_one_node;
6893 val = compare_range_with_value (GE_EXPR, vr, integer_zero_node, &sop);
6897 && integer_onep (val)
6898 && issue_strict_overflow_warning (WARN_STRICT_OVERFLOW_MISC))
6900 location_t location;
6902 if (!gimple_has_location (stmt))
6903 location = input_location;
6905 location = gimple_location (stmt);
6906 warning_at (location, OPT_Wstrict_overflow,
6907 "assuming signed overflow does not occur when "
6908 "simplifying %</%> or %<%%%> to %<>>%> or %<&%>");
6912 if (val && integer_onep (val))
6916 if (rhs_code == TRUNC_DIV_EXPR)
6918 t = build_int_cst (integer_type_node, tree_log2 (op1));
6919 gimple_assign_set_rhs_code (stmt, RSHIFT_EXPR);
6920 gimple_assign_set_rhs1 (stmt, op0);
6921 gimple_assign_set_rhs2 (stmt, t);
6925 t = build_int_cst (TREE_TYPE (op1), 1);
6926 t = int_const_binop (MINUS_EXPR, op1, t);
6927 t = fold_convert (TREE_TYPE (op0), t);
6929 gimple_assign_set_rhs_code (stmt, BIT_AND_EXPR);
6930 gimple_assign_set_rhs1 (stmt, op0);
6931 gimple_assign_set_rhs2 (stmt, t);
6941 /* If the operand to an ABS_EXPR is >= 0, then eliminate the
6942 ABS_EXPR. If the operand is <= 0, then simplify the
6943 ABS_EXPR into a NEGATE_EXPR. */
6946 simplify_abs_using_ranges (gimple stmt)
6949 tree op = gimple_assign_rhs1 (stmt);
6950 tree type = TREE_TYPE (op);
6951 value_range_t *vr = get_value_range (op);
6953 if (TYPE_UNSIGNED (type))
6955 val = integer_zero_node;
6961 val = compare_range_with_value (LE_EXPR, vr, integer_zero_node, &sop);
6965 val = compare_range_with_value (GE_EXPR, vr, integer_zero_node,
6970 if (integer_zerop (val))
6971 val = integer_one_node;
6972 else if (integer_onep (val))
6973 val = integer_zero_node;
6978 && (integer_onep (val) || integer_zerop (val)))
6980 if (sop && issue_strict_overflow_warning (WARN_STRICT_OVERFLOW_MISC))
6982 location_t location;
6984 if (!gimple_has_location (stmt))
6985 location = input_location;
6987 location = gimple_location (stmt);
6988 warning_at (location, OPT_Wstrict_overflow,
6989 "assuming signed overflow does not occur when "
6990 "simplifying %<abs (X)%> to %<X%> or %<-X%>");
6993 gimple_assign_set_rhs1 (stmt, op);
6994 if (integer_onep (val))
6995 gimple_assign_set_rhs_code (stmt, NEGATE_EXPR);
6997 gimple_assign_set_rhs_code (stmt, SSA_NAME);
7006 /* Optimize away redundant BIT_AND_EXPR and BIT_IOR_EXPR.
7007 If all the bits that are being cleared by & are already
7008 known to be zero from VR, or all the bits that are being
7009 set by | are already known to be one from VR, the bit
7010 operation is redundant. */
7013 simplify_bit_ops_using_ranges (gimple_stmt_iterator *gsi, gimple stmt)
7015 tree op0 = gimple_assign_rhs1 (stmt);
7016 tree op1 = gimple_assign_rhs2 (stmt);
7017 tree op = NULL_TREE;
7018 value_range_t vr0 = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
7019 value_range_t vr1 = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
7020 double_int may_be_nonzero0, may_be_nonzero1;
7021 double_int must_be_nonzero0, must_be_nonzero1;
7024 if (TREE_CODE (op0) == SSA_NAME)
7025 vr0 = *(get_value_range (op0));
7026 else if (is_gimple_min_invariant (op0))
7027 set_value_range_to_value (&vr0, op0, NULL);
7031 if (TREE_CODE (op1) == SSA_NAME)
7032 vr1 = *(get_value_range (op1));
7033 else if (is_gimple_min_invariant (op1))
7034 set_value_range_to_value (&vr1, op1, NULL);
7038 if (!zero_nonzero_bits_from_vr (&vr0, &may_be_nonzero0, &must_be_nonzero0))
7040 if (!zero_nonzero_bits_from_vr (&vr1, &may_be_nonzero1, &must_be_nonzero1))
7043 switch (gimple_assign_rhs_code (stmt))
7046 mask = double_int_and_not (may_be_nonzero0, must_be_nonzero1);
7047 if (double_int_zero_p (mask))
7052 mask = double_int_and_not (may_be_nonzero1, must_be_nonzero0);
7053 if (double_int_zero_p (mask))
7060 mask = double_int_and_not (may_be_nonzero0, must_be_nonzero1);
7061 if (double_int_zero_p (mask))
7066 mask = double_int_and_not (may_be_nonzero1, must_be_nonzero0);
7067 if (double_int_zero_p (mask))
7077 if (op == NULL_TREE)
7080 gimple_assign_set_rhs_with_ops (gsi, TREE_CODE (op), op, NULL);
7081 update_stmt (gsi_stmt (*gsi));
7085 /* We are comparing trees OP0 and OP1 using COND_CODE. OP0 has
7086 a known value range VR.
7088 If there is one and only one value which will satisfy the
7089 conditional, then return that value. Else return NULL. */
7092 test_for_singularity (enum tree_code cond_code, tree op0,
7093 tree op1, value_range_t *vr)
7098 /* Extract minimum/maximum values which satisfy the
7099 the conditional as it was written. */
7100 if (cond_code == LE_EXPR || cond_code == LT_EXPR)
7102 /* This should not be negative infinity; there is no overflow
7104 min = TYPE_MIN_VALUE (TREE_TYPE (op0));
7107 if (cond_code == LT_EXPR && !is_overflow_infinity (max))
7109 tree one = build_int_cst (TREE_TYPE (op0), 1);
7110 max = fold_build2 (MINUS_EXPR, TREE_TYPE (op0), max, one);
7112 TREE_NO_WARNING (max) = 1;
7115 else if (cond_code == GE_EXPR || cond_code == GT_EXPR)
7117 /* This should not be positive infinity; there is no overflow
7119 max = TYPE_MAX_VALUE (TREE_TYPE (op0));
7122 if (cond_code == GT_EXPR && !is_overflow_infinity (min))
7124 tree one = build_int_cst (TREE_TYPE (op0), 1);
7125 min = fold_build2 (PLUS_EXPR, TREE_TYPE (op0), min, one);
7127 TREE_NO_WARNING (min) = 1;
7131 /* Now refine the minimum and maximum values using any
7132 value range information we have for op0. */
7135 if (compare_values (vr->min, min) == 1)
7137 if (compare_values (vr->max, max) == -1)
7140 /* If the new min/max values have converged to a single value,
7141 then there is only one value which can satisfy the condition,
7142 return that value. */
7143 if (operand_equal_p (min, max, 0) && is_gimple_min_invariant (min))
7149 /* Simplify a conditional using a relational operator to an equality
7150 test if the range information indicates only one value can satisfy
7151 the original conditional. */
7154 simplify_cond_using_ranges (gimple stmt)
7156 tree op0 = gimple_cond_lhs (stmt);
7157 tree op1 = gimple_cond_rhs (stmt);
7158 enum tree_code cond_code = gimple_cond_code (stmt);
7160 if (cond_code != NE_EXPR
7161 && cond_code != EQ_EXPR
7162 && TREE_CODE (op0) == SSA_NAME
7163 && INTEGRAL_TYPE_P (TREE_TYPE (op0))
7164 && is_gimple_min_invariant (op1))
7166 value_range_t *vr = get_value_range (op0);
7168 /* If we have range information for OP0, then we might be
7169 able to simplify this conditional. */
7170 if (vr->type == VR_RANGE)
7172 tree new_tree = test_for_singularity (cond_code, op0, op1, vr);
7178 fprintf (dump_file, "Simplified relational ");
7179 print_gimple_stmt (dump_file, stmt, 0, 0);
7180 fprintf (dump_file, " into ");
7183 gimple_cond_set_code (stmt, EQ_EXPR);
7184 gimple_cond_set_lhs (stmt, op0);
7185 gimple_cond_set_rhs (stmt, new_tree);
7191 print_gimple_stmt (dump_file, stmt, 0, 0);
7192 fprintf (dump_file, "\n");
7198 /* Try again after inverting the condition. We only deal
7199 with integral types here, so no need to worry about
7200 issues with inverting FP comparisons. */
7201 cond_code = invert_tree_comparison (cond_code, false);
7202 new_tree = test_for_singularity (cond_code, op0, op1, vr);
7208 fprintf (dump_file, "Simplified relational ");
7209 print_gimple_stmt (dump_file, stmt, 0, 0);
7210 fprintf (dump_file, " into ");
7213 gimple_cond_set_code (stmt, NE_EXPR);
7214 gimple_cond_set_lhs (stmt, op0);
7215 gimple_cond_set_rhs (stmt, new_tree);
7221 print_gimple_stmt (dump_file, stmt, 0, 0);
7222 fprintf (dump_file, "\n");
7233 /* Simplify a switch statement using the value range of the switch
7237 simplify_switch_using_ranges (gimple stmt)
7239 tree op = gimple_switch_index (stmt);
7244 size_t i = 0, j = 0, n, n2;
7248 if (TREE_CODE (op) == SSA_NAME)
7250 vr = get_value_range (op);
7252 /* We can only handle integer ranges. */
7253 if (vr->type != VR_RANGE
7254 || symbolic_range_p (vr))
7257 /* Find case label for min/max of the value range. */
7258 take_default = !find_case_label_range (stmt, vr->min, vr->max, &i, &j);
7260 else if (TREE_CODE (op) == INTEGER_CST)
7262 take_default = !find_case_label_index (stmt, 1, op, &i);
7276 n = gimple_switch_num_labels (stmt);
7278 /* Bail out if this is just all edges taken. */
7284 /* Build a new vector of taken case labels. */
7285 vec2 = make_tree_vec (j - i + 1 + (int)take_default);
7288 /* Add the default edge, if necessary. */
7290 TREE_VEC_ELT (vec2, n2++) = gimple_switch_default_label (stmt);
7292 for (; i <= j; ++i, ++n2)
7293 TREE_VEC_ELT (vec2, n2) = gimple_switch_label (stmt, i);
7295 /* Mark needed edges. */
7296 for (i = 0; i < n2; ++i)
7298 e = find_edge (gimple_bb (stmt),
7299 label_to_block (CASE_LABEL (TREE_VEC_ELT (vec2, i))));
7300 e->aux = (void *)-1;
7303 /* Queue not needed edges for later removal. */
7304 FOR_EACH_EDGE (e, ei, gimple_bb (stmt)->succs)
7306 if (e->aux == (void *)-1)
7312 if (dump_file && (dump_flags & TDF_DETAILS))
7314 fprintf (dump_file, "removing unreachable case label\n");
7316 VEC_safe_push (edge, heap, to_remove_edges, e);
7317 e->flags &= ~EDGE_EXECUTABLE;
7320 /* And queue an update for the stmt. */
7323 VEC_safe_push (switch_update, heap, to_update_switch_stmts, &su);
7327 /* Simplify an integral conversion from an SSA name in STMT. */
7330 simplify_conversion_using_ranges (gimple stmt)
7332 tree innerop, middleop, finaltype;
7334 value_range_t *innervr;
7335 double_int innermin, innermax, middlemin, middlemax;
7337 finaltype = TREE_TYPE (gimple_assign_lhs (stmt));
7338 if (!INTEGRAL_TYPE_P (finaltype))
7340 middleop = gimple_assign_rhs1 (stmt);
7341 def_stmt = SSA_NAME_DEF_STMT (middleop);
7342 if (!is_gimple_assign (def_stmt)
7343 || !CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (def_stmt)))
7345 innerop = gimple_assign_rhs1 (def_stmt);
7346 if (TREE_CODE (innerop) != SSA_NAME)
7349 /* Get the value-range of the inner operand. */
7350 innervr = get_value_range (innerop);
7351 if (innervr->type != VR_RANGE
7352 || TREE_CODE (innervr->min) != INTEGER_CST
7353 || TREE_CODE (innervr->max) != INTEGER_CST)
7356 /* Simulate the conversion chain to check if the result is equal if
7357 the middle conversion is removed. */
7358 innermin = tree_to_double_int (innervr->min);
7359 innermax = tree_to_double_int (innervr->max);
7360 middlemin = double_int_ext (innermin, TYPE_PRECISION (TREE_TYPE (middleop)),
7361 TYPE_UNSIGNED (TREE_TYPE (middleop)));
7362 middlemax = double_int_ext (innermax, TYPE_PRECISION (TREE_TYPE (middleop)),
7363 TYPE_UNSIGNED (TREE_TYPE (middleop)));
7364 /* If the middle values do not represent a proper range fail. */
7365 if (double_int_cmp (middlemin, middlemax,
7366 TYPE_UNSIGNED (TREE_TYPE (middleop))) > 0)
7368 if (!double_int_equal_p (double_int_ext (middlemin,
7369 TYPE_PRECISION (finaltype),
7370 TYPE_UNSIGNED (finaltype)),
7371 double_int_ext (innermin,
7372 TYPE_PRECISION (finaltype),
7373 TYPE_UNSIGNED (finaltype)))
7374 || !double_int_equal_p (double_int_ext (middlemax,
7375 TYPE_PRECISION (finaltype),
7376 TYPE_UNSIGNED (finaltype)),
7377 double_int_ext (innermax,
7378 TYPE_PRECISION (finaltype),
7379 TYPE_UNSIGNED (finaltype))))
7382 gimple_assign_set_rhs1 (stmt, innerop);
7387 /* Return whether the value range *VR fits in an integer type specified
7388 by PRECISION and UNSIGNED_P. */
7391 range_fits_type_p (value_range_t *vr, unsigned precision, bool unsigned_p)
7394 unsigned src_precision;
7397 /* We can only handle integral and pointer types. */
7398 src_type = TREE_TYPE (vr->min);
7399 if (!INTEGRAL_TYPE_P (src_type)
7400 && !POINTER_TYPE_P (src_type))
7403 /* An extension is always fine, so is an identity transform. */
7404 src_precision = TYPE_PRECISION (TREE_TYPE (vr->min));
7405 if (src_precision < precision
7406 || (src_precision == precision
7407 && TYPE_UNSIGNED (src_type) == unsigned_p))
7410 /* Now we can only handle ranges with constant bounds. */
7411 if (vr->type != VR_RANGE
7412 || TREE_CODE (vr->min) != INTEGER_CST
7413 || TREE_CODE (vr->max) != INTEGER_CST)
7416 /* For precision-preserving sign-changes the MSB of the double-int
7418 if (src_precision == precision
7419 && (TREE_INT_CST_HIGH (vr->min) | TREE_INT_CST_HIGH (vr->max)) < 0)
7422 /* Then we can perform the conversion on both ends and compare
7423 the result for equality. */
7424 tem = double_int_ext (tree_to_double_int (vr->min), precision, unsigned_p);
7425 if (!double_int_equal_p (tree_to_double_int (vr->min), tem))
7427 tem = double_int_ext (tree_to_double_int (vr->max), precision, unsigned_p);
7428 if (!double_int_equal_p (tree_to_double_int (vr->max), tem))
7434 /* Simplify a conversion from integral SSA name to float in STMT. */
7437 simplify_float_conversion_using_ranges (gimple_stmt_iterator *gsi, gimple stmt)
7439 tree rhs1 = gimple_assign_rhs1 (stmt);
7440 value_range_t *vr = get_value_range (rhs1);
7441 enum machine_mode fltmode = TYPE_MODE (TREE_TYPE (gimple_assign_lhs (stmt)));
7442 enum machine_mode mode;
7446 /* We can only handle constant ranges. */
7447 if (vr->type != VR_RANGE
7448 || TREE_CODE (vr->min) != INTEGER_CST
7449 || TREE_CODE (vr->max) != INTEGER_CST)
7452 /* First check if we can use a signed type in place of an unsigned. */
7453 if (TYPE_UNSIGNED (TREE_TYPE (rhs1))
7454 && (can_float_p (fltmode, TYPE_MODE (TREE_TYPE (rhs1)), 0)
7455 != CODE_FOR_nothing)
7456 && range_fits_type_p (vr, GET_MODE_PRECISION
7457 (TYPE_MODE (TREE_TYPE (rhs1))), 0))
7458 mode = TYPE_MODE (TREE_TYPE (rhs1));
7459 /* If we can do the conversion in the current input mode do nothing. */
7460 else if (can_float_p (fltmode, TYPE_MODE (TREE_TYPE (rhs1)),
7461 TYPE_UNSIGNED (TREE_TYPE (rhs1))))
7463 /* Otherwise search for a mode we can use, starting from the narrowest
7464 integer mode available. */
7467 mode = GET_CLASS_NARROWEST_MODE (MODE_INT);
7470 /* If we cannot do a signed conversion to float from mode
7471 or if the value-range does not fit in the signed type
7472 try with a wider mode. */
7473 if (can_float_p (fltmode, mode, 0) != CODE_FOR_nothing
7474 && range_fits_type_p (vr, GET_MODE_PRECISION (mode), 0))
7477 mode = GET_MODE_WIDER_MODE (mode);
7478 /* But do not widen the input. Instead leave that to the
7479 optabs expansion code. */
7480 if (GET_MODE_PRECISION (mode) > TYPE_PRECISION (TREE_TYPE (rhs1)))
7483 while (mode != VOIDmode);
7484 if (mode == VOIDmode)
7488 /* It works, insert a truncation or sign-change before the
7489 float conversion. */
7490 tem = create_tmp_var (build_nonstandard_integer_type
7491 (GET_MODE_PRECISION (mode), 0), NULL);
7492 conv = gimple_build_assign_with_ops (NOP_EXPR, tem, rhs1, NULL_TREE);
7493 tem = make_ssa_name (tem, conv);
7494 gimple_assign_set_lhs (conv, tem);
7495 gsi_insert_before (gsi, conv, GSI_SAME_STMT);
7496 gimple_assign_set_rhs1 (stmt, tem);
7502 /* Simplify STMT using ranges if possible. */
7505 simplify_stmt_using_ranges (gimple_stmt_iterator *gsi)
7507 gimple stmt = gsi_stmt (*gsi);
7508 if (is_gimple_assign (stmt))
7510 enum tree_code rhs_code = gimple_assign_rhs_code (stmt);
7511 tree rhs1 = gimple_assign_rhs1 (stmt);
7517 case TRUTH_NOT_EXPR:
7518 /* Transform EQ_EXPR, NE_EXPR, TRUTH_NOT_EXPR into BIT_XOR_EXPR
7519 or identity if the RHS is zero or one, and the LHS are known
7520 to be boolean values. Transform all TRUTH_*_EXPR into
7521 BIT_*_EXPR if both arguments are known to be boolean values. */
7522 if (INTEGRAL_TYPE_P (TREE_TYPE (rhs1)))
7523 return simplify_truth_ops_using_ranges (gsi, stmt);
7526 /* Transform TRUNC_DIV_EXPR and TRUNC_MOD_EXPR into RSHIFT_EXPR
7527 and BIT_AND_EXPR respectively if the first operand is greater
7528 than zero and the second operand is an exact power of two. */
7529 case TRUNC_DIV_EXPR:
7530 case TRUNC_MOD_EXPR:
7531 if (INTEGRAL_TYPE_P (TREE_TYPE (rhs1))
7532 && integer_pow2p (gimple_assign_rhs2 (stmt)))
7533 return simplify_div_or_mod_using_ranges (stmt);
7536 /* Transform ABS (X) into X or -X as appropriate. */
7538 if (TREE_CODE (rhs1) == SSA_NAME
7539 && INTEGRAL_TYPE_P (TREE_TYPE (rhs1)))
7540 return simplify_abs_using_ranges (stmt);
7545 /* Optimize away BIT_AND_EXPR and BIT_IOR_EXPR
7546 if all the bits being cleared are already cleared or
7547 all the bits being set are already set. */
7548 if (INTEGRAL_TYPE_P (TREE_TYPE (rhs1)))
7549 return simplify_bit_ops_using_ranges (gsi, stmt);
7553 if (TREE_CODE (rhs1) == SSA_NAME
7554 && INTEGRAL_TYPE_P (TREE_TYPE (rhs1)))
7555 return simplify_conversion_using_ranges (stmt);
7559 if (TREE_CODE (rhs1) == SSA_NAME
7560 && INTEGRAL_TYPE_P (TREE_TYPE (rhs1)))
7561 return simplify_float_conversion_using_ranges (gsi, stmt);
7568 else if (gimple_code (stmt) == GIMPLE_COND)
7569 return simplify_cond_using_ranges (stmt);
7570 else if (gimple_code (stmt) == GIMPLE_SWITCH)
7571 return simplify_switch_using_ranges (stmt);
7576 /* If the statement pointed by SI has a predicate whose value can be
7577 computed using the value range information computed by VRP, compute
7578 its value and return true. Otherwise, return false. */
7581 fold_predicate_in (gimple_stmt_iterator *si)
7583 bool assignment_p = false;
7585 gimple stmt = gsi_stmt (*si);
7587 if (is_gimple_assign (stmt)
7588 && TREE_CODE_CLASS (gimple_assign_rhs_code (stmt)) == tcc_comparison)
7590 assignment_p = true;
7591 val = vrp_evaluate_conditional (gimple_assign_rhs_code (stmt),
7592 gimple_assign_rhs1 (stmt),
7593 gimple_assign_rhs2 (stmt),
7596 else if (gimple_code (stmt) == GIMPLE_COND)
7597 val = vrp_evaluate_conditional (gimple_cond_code (stmt),
7598 gimple_cond_lhs (stmt),
7599 gimple_cond_rhs (stmt),
7607 val = fold_convert (gimple_expr_type (stmt), val);
7611 fprintf (dump_file, "Folding predicate ");
7612 print_gimple_expr (dump_file, stmt, 0, 0);
7613 fprintf (dump_file, " to ");
7614 print_generic_expr (dump_file, val, 0);
7615 fprintf (dump_file, "\n");
7618 if (is_gimple_assign (stmt))
7619 gimple_assign_set_rhs_from_tree (si, val);
7622 gcc_assert (gimple_code (stmt) == GIMPLE_COND);
7623 if (integer_zerop (val))
7624 gimple_cond_make_false (stmt);
7625 else if (integer_onep (val))
7626 gimple_cond_make_true (stmt);
7637 /* Callback for substitute_and_fold folding the stmt at *SI. */
7640 vrp_fold_stmt (gimple_stmt_iterator *si)
7642 if (fold_predicate_in (si))
7645 return simplify_stmt_using_ranges (si);
7648 /* Stack of dest,src equivalency pairs that need to be restored after
7649 each attempt to thread a block's incoming edge to an outgoing edge.
7651 A NULL entry is used to mark the end of pairs which need to be
7653 static VEC(tree,heap) *stack;
7655 /* A trivial wrapper so that we can present the generic jump threading
7656 code with a simple API for simplifying statements. STMT is the
7657 statement we want to simplify, WITHIN_STMT provides the location
7658 for any overflow warnings. */
7661 simplify_stmt_for_jump_threading (gimple stmt, gimple within_stmt)
7663 /* We only use VRP information to simplify conditionals. This is
7664 overly conservative, but it's unclear if doing more would be
7665 worth the compile time cost. */
7666 if (gimple_code (stmt) != GIMPLE_COND)
7669 return vrp_evaluate_conditional (gimple_cond_code (stmt),
7670 gimple_cond_lhs (stmt),
7671 gimple_cond_rhs (stmt), within_stmt);
7674 /* Blocks which have more than one predecessor and more than
7675 one successor present jump threading opportunities, i.e.,
7676 when the block is reached from a specific predecessor, we
7677 may be able to determine which of the outgoing edges will
7678 be traversed. When this optimization applies, we are able
7679 to avoid conditionals at runtime and we may expose secondary
7680 optimization opportunities.
7682 This routine is effectively a driver for the generic jump
7683 threading code. It basically just presents the generic code
7684 with edges that may be suitable for jump threading.
7686 Unlike DOM, we do not iterate VRP if jump threading was successful.
7687 While iterating may expose new opportunities for VRP, it is expected
7688 those opportunities would be very limited and the compile time cost
7689 to expose those opportunities would be significant.
7691 As jump threading opportunities are discovered, they are registered
7692 for later realization. */
7695 identify_jump_threads (void)
7702 /* Ugh. When substituting values earlier in this pass we can
7703 wipe the dominance information. So rebuild the dominator
7704 information as we need it within the jump threading code. */
7705 calculate_dominance_info (CDI_DOMINATORS);
7707 /* We do not allow VRP information to be used for jump threading
7708 across a back edge in the CFG. Otherwise it becomes too
7709 difficult to avoid eliminating loop exit tests. Of course
7710 EDGE_DFS_BACK is not accurate at this time so we have to
7712 mark_dfs_back_edges ();
7714 /* Do not thread across edges we are about to remove. Just marking
7715 them as EDGE_DFS_BACK will do. */
7716 FOR_EACH_VEC_ELT (edge, to_remove_edges, i, e)
7717 e->flags |= EDGE_DFS_BACK;
7719 /* Allocate our unwinder stack to unwind any temporary equivalences
7720 that might be recorded. */
7721 stack = VEC_alloc (tree, heap, 20);
7723 /* To avoid lots of silly node creation, we create a single
7724 conditional and just modify it in-place when attempting to
7726 dummy = gimple_build_cond (EQ_EXPR,
7727 integer_zero_node, integer_zero_node,
7730 /* Walk through all the blocks finding those which present a
7731 potential jump threading opportunity. We could set this up
7732 as a dominator walker and record data during the walk, but
7733 I doubt it's worth the effort for the classes of jump
7734 threading opportunities we are trying to identify at this
7735 point in compilation. */
7740 /* If the generic jump threading code does not find this block
7741 interesting, then there is nothing to do. */
7742 if (! potentially_threadable_block (bb))
7745 /* We only care about blocks ending in a COND_EXPR. While there
7746 may be some value in handling SWITCH_EXPR here, I doubt it's
7747 terribly important. */
7748 last = gsi_stmt (gsi_last_bb (bb));
7750 /* We're basically looking for a switch or any kind of conditional with
7751 integral or pointer type arguments. Note the type of the second
7752 argument will be the same as the first argument, so no need to
7753 check it explicitly. */
7754 if (gimple_code (last) == GIMPLE_SWITCH
7755 || (gimple_code (last) == GIMPLE_COND
7756 && TREE_CODE (gimple_cond_lhs (last)) == SSA_NAME
7757 && (INTEGRAL_TYPE_P (TREE_TYPE (gimple_cond_lhs (last)))
7758 || POINTER_TYPE_P (TREE_TYPE (gimple_cond_lhs (last))))
7759 && (TREE_CODE (gimple_cond_rhs (last)) == SSA_NAME
7760 || is_gimple_min_invariant (gimple_cond_rhs (last)))))
7764 /* We've got a block with multiple predecessors and multiple
7765 successors which also ends in a suitable conditional or
7766 switch statement. For each predecessor, see if we can thread
7767 it to a specific successor. */
7768 FOR_EACH_EDGE (e, ei, bb->preds)
7770 /* Do not thread across back edges or abnormal edges
7772 if (e->flags & (EDGE_DFS_BACK | EDGE_COMPLEX))
7775 thread_across_edge (dummy, e, true, &stack,
7776 simplify_stmt_for_jump_threading);
7781 /* We do not actually update the CFG or SSA graphs at this point as
7782 ASSERT_EXPRs are still in the IL and cfg cleanup code does not yet
7783 handle ASSERT_EXPRs gracefully. */
7786 /* We identified all the jump threading opportunities earlier, but could
7787 not transform the CFG at that time. This routine transforms the
7788 CFG and arranges for the dominator tree to be rebuilt if necessary.
7790 Note the SSA graph update will occur during the normal TODO
7791 processing by the pass manager. */
7793 finalize_jump_threads (void)
7795 thread_through_all_blocks (false);
7796 VEC_free (tree, heap, stack);
7800 /* Traverse all the blocks folding conditionals with known ranges. */
7807 values_propagated = true;
7811 fprintf (dump_file, "\nValue ranges after VRP:\n\n");
7812 dump_all_value_ranges (dump_file);
7813 fprintf (dump_file, "\n");
7816 substitute_and_fold (op_with_constant_singleton_value_range,
7817 vrp_fold_stmt, false);
7819 if (warn_array_bounds)
7820 check_all_array_refs ();
7822 /* We must identify jump threading opportunities before we release
7823 the datastructures built by VRP. */
7824 identify_jump_threads ();
7826 /* Free allocated memory. */
7827 for (i = 0; i < num_vr_values; i++)
7830 BITMAP_FREE (vr_value[i]->equiv);
7835 free (vr_phi_edge_counts);
7837 /* So that we can distinguish between VRP data being available
7838 and not available. */
7840 vr_phi_edge_counts = NULL;
7844 /* Main entry point to VRP (Value Range Propagation). This pass is
7845 loosely based on J. R. C. Patterson, ``Accurate Static Branch
7846 Prediction by Value Range Propagation,'' in SIGPLAN Conference on
7847 Programming Language Design and Implementation, pp. 67-78, 1995.
7848 Also available at http://citeseer.ist.psu.edu/patterson95accurate.html
7850 This is essentially an SSA-CCP pass modified to deal with ranges
7851 instead of constants.
7853 While propagating ranges, we may find that two or more SSA name
7854 have equivalent, though distinct ranges. For instance,
7857 2 p_4 = ASSERT_EXPR <p_3, p_3 != 0>
7859 4 p_5 = ASSERT_EXPR <p_4, p_4 == q_2>;
7863 In the code above, pointer p_5 has range [q_2, q_2], but from the
7864 code we can also determine that p_5 cannot be NULL and, if q_2 had
7865 a non-varying range, p_5's range should also be compatible with it.
7867 These equivalences are created by two expressions: ASSERT_EXPR and
7868 copy operations. Since p_5 is an assertion on p_4, and p_4 was the
7869 result of another assertion, then we can use the fact that p_5 and
7870 p_4 are equivalent when evaluating p_5's range.
7872 Together with value ranges, we also propagate these equivalences
7873 between names so that we can take advantage of information from
7874 multiple ranges when doing final replacement. Note that this
7875 equivalency relation is transitive but not symmetric.
7877 In the example above, p_5 is equivalent to p_4, q_2 and p_3, but we
7878 cannot assert that q_2 is equivalent to p_5 because q_2 may be used
7879 in contexts where that assertion does not hold (e.g., in line 6).
7881 TODO, the main difference between this pass and Patterson's is that
7882 we do not propagate edge probabilities. We only compute whether
7883 edges can be taken or not. That is, instead of having a spectrum
7884 of jump probabilities between 0 and 1, we only deal with 0, 1 and
7885 DON'T KNOW. In the future, it may be worthwhile to propagate
7886 probabilities to aid branch prediction. */
7895 loop_optimizer_init (LOOPS_NORMAL | LOOPS_HAVE_RECORDED_EXITS);
7896 rewrite_into_loop_closed_ssa (NULL, TODO_update_ssa);
7899 insert_range_assertions ();
7901 /* Estimate number of iterations - but do not use undefined behavior
7902 for this. We can't do this lazily as other functions may compute
7903 this using undefined behavior. */
7904 free_numbers_of_iterations_estimates ();
7905 estimate_numbers_of_iterations (false);
7907 to_remove_edges = VEC_alloc (edge, heap, 10);
7908 to_update_switch_stmts = VEC_alloc (switch_update, heap, 5);
7909 threadedge_initialize_values ();
7912 ssa_propagate (vrp_visit_stmt, vrp_visit_phi_node);
7915 free_numbers_of_iterations_estimates ();
7917 /* ASSERT_EXPRs must be removed before finalizing jump threads
7918 as finalizing jump threads calls the CFG cleanup code which
7919 does not properly handle ASSERT_EXPRs. */
7920 remove_range_assertions ();
7922 /* If we exposed any new variables, go ahead and put them into
7923 SSA form now, before we handle jump threading. This simplifies
7924 interactions between rewriting of _DECL nodes into SSA form
7925 and rewriting SSA_NAME nodes into SSA form after block
7926 duplication and CFG manipulation. */
7927 update_ssa (TODO_update_ssa);
7929 finalize_jump_threads ();
7931 /* Remove dead edges from SWITCH_EXPR optimization. This leaves the
7932 CFG in a broken state and requires a cfg_cleanup run. */
7933 FOR_EACH_VEC_ELT (edge, to_remove_edges, i, e)
7935 /* Update SWITCH_EXPR case label vector. */
7936 FOR_EACH_VEC_ELT (switch_update, to_update_switch_stmts, i, su)
7939 size_t n = TREE_VEC_LENGTH (su->vec);
7941 gimple_switch_set_num_labels (su->stmt, n);
7942 for (j = 0; j < n; j++)
7943 gimple_switch_set_label (su->stmt, j, TREE_VEC_ELT (su->vec, j));
7944 /* As we may have replaced the default label with a regular one
7945 make sure to make it a real default label again. This ensures
7946 optimal expansion. */
7947 label = gimple_switch_default_label (su->stmt);
7948 CASE_LOW (label) = NULL_TREE;
7949 CASE_HIGH (label) = NULL_TREE;
7952 if (VEC_length (edge, to_remove_edges) > 0)
7953 free_dominance_info (CDI_DOMINATORS);
7955 VEC_free (edge, heap, to_remove_edges);
7956 VEC_free (switch_update, heap, to_update_switch_stmts);
7957 threadedge_finalize_values ();
7960 loop_optimizer_finalize ();
7967 return flag_tree_vrp != 0;
7970 struct gimple_opt_pass pass_vrp =
7975 gate_vrp, /* gate */
7976 execute_vrp, /* execute */
7979 0, /* static_pass_number */
7980 TV_TREE_VRP, /* tv_id */
7981 PROP_ssa, /* properties_required */
7982 0, /* properties_provided */
7983 0, /* properties_destroyed */
7984 0, /* todo_flags_start */
7989 | TODO_ggc_collect /* todo_flags_finish */