1 /* Support routines for Value Range Propagation (VRP).
2 Copyright (C) 2005, 2006, 2007, 2008, 2009, 2010
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 "diagnostic.h"
38 #include "tree-scalar-evolution.h"
39 #include "tree-ssa-propagate.h"
40 #include "tree-chrec.h"
43 /* Set of SSA names found live during the RPO traversal of the function
44 for still active basic-blocks. */
47 /* Return true if the SSA name NAME is live on the edge E. */
50 live_on_edge (edge e, tree name)
52 return (live[e->dest->index]
53 && TEST_BIT (live[e->dest->index], SSA_NAME_VERSION (name)));
56 /* Local functions. */
57 static int compare_values (tree val1, tree val2);
58 static int compare_values_warnv (tree val1, tree val2, bool *);
59 static void vrp_meet (value_range_t *, value_range_t *);
60 static tree vrp_evaluate_conditional_warnv_with_ops (enum tree_code,
61 tree, tree, bool, bool *,
64 /* Location information for ASSERT_EXPRs. Each instance of this
65 structure describes an ASSERT_EXPR for an SSA name. Since a single
66 SSA name may have more than one assertion associated with it, these
67 locations are kept in a linked list attached to the corresponding
71 /* Basic block where the assertion would be inserted. */
74 /* Some assertions need to be inserted on an edge (e.g., assertions
75 generated by COND_EXPRs). In those cases, BB will be NULL. */
78 /* Pointer to the statement that generated this assertion. */
79 gimple_stmt_iterator si;
81 /* Predicate code for the ASSERT_EXPR. Must be COMPARISON_CLASS_P. */
82 enum tree_code comp_code;
84 /* Value being compared against. */
87 /* Expression to compare. */
90 /* Next node in the linked list. */
91 struct assert_locus_d *next;
94 typedef struct assert_locus_d *assert_locus_t;
96 /* If bit I is present, it means that SSA name N_i has a list of
97 assertions that should be inserted in the IL. */
98 static bitmap need_assert_for;
100 /* Array of locations lists where to insert assertions. ASSERTS_FOR[I]
101 holds a list of ASSERT_LOCUS_T nodes that describe where
102 ASSERT_EXPRs for SSA name N_I should be inserted. */
103 static assert_locus_t *asserts_for;
105 /* Value range array. After propagation, VR_VALUE[I] holds the range
106 of values that SSA name N_I may take. */
107 static value_range_t **vr_value;
109 /* For a PHI node which sets SSA name N_I, VR_COUNTS[I] holds the
110 number of executable edges we saw the last time we visited the
112 static int *vr_phi_edge_counts;
119 static VEC (edge, heap) *to_remove_edges;
120 DEF_VEC_O(switch_update);
121 DEF_VEC_ALLOC_O(switch_update, heap);
122 static VEC (switch_update, heap) *to_update_switch_stmts;
125 /* Return the maximum value for TYPE. */
128 vrp_val_max (const_tree type)
130 if (!INTEGRAL_TYPE_P (type))
133 return TYPE_MAX_VALUE (type);
136 /* Return the minimum value for TYPE. */
139 vrp_val_min (const_tree type)
141 if (!INTEGRAL_TYPE_P (type))
144 return TYPE_MIN_VALUE (type);
147 /* Return whether VAL is equal to the maximum value of its type. This
148 will be true for a positive overflow infinity. We can't do a
149 simple equality comparison with TYPE_MAX_VALUE because C typedefs
150 and Ada subtypes can produce types whose TYPE_MAX_VALUE is not ==
151 to the integer constant with the same value in the type. */
154 vrp_val_is_max (const_tree val)
156 tree type_max = vrp_val_max (TREE_TYPE (val));
157 return (val == type_max
158 || (type_max != NULL_TREE
159 && operand_equal_p (val, type_max, 0)));
162 /* Return whether VAL is equal to the minimum value of its type. This
163 will be true for a negative overflow infinity. */
166 vrp_val_is_min (const_tree val)
168 tree type_min = vrp_val_min (TREE_TYPE (val));
169 return (val == type_min
170 || (type_min != NULL_TREE
171 && operand_equal_p (val, type_min, 0)));
175 /* Return whether TYPE should use an overflow infinity distinct from
176 TYPE_{MIN,MAX}_VALUE. We use an overflow infinity value to
177 represent a signed overflow during VRP computations. An infinity
178 is distinct from a half-range, which will go from some number to
179 TYPE_{MIN,MAX}_VALUE. */
182 needs_overflow_infinity (const_tree type)
184 return INTEGRAL_TYPE_P (type) && !TYPE_OVERFLOW_WRAPS (type);
187 /* Return whether TYPE can support our overflow infinity
188 representation: we use the TREE_OVERFLOW flag, which only exists
189 for constants. If TYPE doesn't support this, we don't optimize
190 cases which would require signed overflow--we drop them to
194 supports_overflow_infinity (const_tree type)
196 tree min = vrp_val_min (type), max = vrp_val_max (type);
197 #ifdef ENABLE_CHECKING
198 gcc_assert (needs_overflow_infinity (type));
200 return (min != NULL_TREE
201 && CONSTANT_CLASS_P (min)
203 && CONSTANT_CLASS_P (max));
206 /* VAL is the maximum or minimum value of a type. Return a
207 corresponding overflow infinity. */
210 make_overflow_infinity (tree val)
212 #ifdef ENABLE_CHECKING
213 gcc_assert (val != NULL_TREE && CONSTANT_CLASS_P (val));
215 val = copy_node (val);
216 TREE_OVERFLOW (val) = 1;
220 /* Return a negative overflow infinity for TYPE. */
223 negative_overflow_infinity (tree type)
225 #ifdef ENABLE_CHECKING
226 gcc_assert (supports_overflow_infinity (type));
228 return make_overflow_infinity (vrp_val_min (type));
231 /* Return a positive overflow infinity for TYPE. */
234 positive_overflow_infinity (tree type)
236 #ifdef ENABLE_CHECKING
237 gcc_assert (supports_overflow_infinity (type));
239 return make_overflow_infinity (vrp_val_max (type));
242 /* Return whether VAL is a negative overflow infinity. */
245 is_negative_overflow_infinity (const_tree val)
247 return (needs_overflow_infinity (TREE_TYPE (val))
248 && CONSTANT_CLASS_P (val)
249 && TREE_OVERFLOW (val)
250 && vrp_val_is_min (val));
253 /* Return whether VAL is a positive overflow infinity. */
256 is_positive_overflow_infinity (const_tree val)
258 return (needs_overflow_infinity (TREE_TYPE (val))
259 && CONSTANT_CLASS_P (val)
260 && TREE_OVERFLOW (val)
261 && vrp_val_is_max (val));
264 /* Return whether VAL is a positive or negative overflow infinity. */
267 is_overflow_infinity (const_tree val)
269 return (needs_overflow_infinity (TREE_TYPE (val))
270 && CONSTANT_CLASS_P (val)
271 && TREE_OVERFLOW (val)
272 && (vrp_val_is_min (val) || vrp_val_is_max (val)));
275 /* Return whether STMT has a constant rhs that is_overflow_infinity. */
278 stmt_overflow_infinity (gimple stmt)
280 if (is_gimple_assign (stmt)
281 && get_gimple_rhs_class (gimple_assign_rhs_code (stmt)) ==
283 return is_overflow_infinity (gimple_assign_rhs1 (stmt));
287 /* If VAL is now an overflow infinity, return VAL. Otherwise, return
288 the same value with TREE_OVERFLOW clear. This can be used to avoid
289 confusing a regular value with an overflow value. */
292 avoid_overflow_infinity (tree val)
294 if (!is_overflow_infinity (val))
297 if (vrp_val_is_max (val))
298 return vrp_val_max (TREE_TYPE (val));
301 #ifdef ENABLE_CHECKING
302 gcc_assert (vrp_val_is_min (val));
304 return vrp_val_min (TREE_TYPE (val));
309 /* Return true if ARG is marked with the nonnull attribute in the
310 current function signature. */
313 nonnull_arg_p (const_tree arg)
315 tree t, attrs, fntype;
316 unsigned HOST_WIDE_INT arg_num;
318 gcc_assert (TREE_CODE (arg) == PARM_DECL && POINTER_TYPE_P (TREE_TYPE (arg)));
320 /* The static chain decl is always non null. */
321 if (arg == cfun->static_chain_decl)
324 fntype = TREE_TYPE (current_function_decl);
325 attrs = lookup_attribute ("nonnull", TYPE_ATTRIBUTES (fntype));
327 /* If "nonnull" wasn't specified, we know nothing about the argument. */
328 if (attrs == NULL_TREE)
331 /* If "nonnull" applies to all the arguments, then ARG is non-null. */
332 if (TREE_VALUE (attrs) == NULL_TREE)
335 /* Get the position number for ARG in the function signature. */
336 for (arg_num = 1, t = DECL_ARGUMENTS (current_function_decl);
338 t = TREE_CHAIN (t), arg_num++)
344 gcc_assert (t == arg);
346 /* Now see if ARG_NUM is mentioned in the nonnull list. */
347 for (t = TREE_VALUE (attrs); t; t = TREE_CHAIN (t))
349 if (compare_tree_int (TREE_VALUE (t), arg_num) == 0)
357 /* Set value range VR to VR_VARYING. */
360 set_value_range_to_varying (value_range_t *vr)
362 vr->type = VR_VARYING;
363 vr->min = vr->max = NULL_TREE;
365 bitmap_clear (vr->equiv);
369 /* Set value range VR to {T, MIN, MAX, EQUIV}. */
372 set_value_range (value_range_t *vr, enum value_range_type t, tree min,
373 tree max, bitmap equiv)
375 #if defined ENABLE_CHECKING
376 /* Check the validity of the range. */
377 if (t == VR_RANGE || t == VR_ANTI_RANGE)
381 gcc_assert (min && max);
383 if (INTEGRAL_TYPE_P (TREE_TYPE (min)) && t == VR_ANTI_RANGE)
384 gcc_assert (!vrp_val_is_min (min) || !vrp_val_is_max (max));
386 cmp = compare_values (min, max);
387 gcc_assert (cmp == 0 || cmp == -1 || cmp == -2);
389 if (needs_overflow_infinity (TREE_TYPE (min)))
390 gcc_assert (!is_overflow_infinity (min)
391 || !is_overflow_infinity (max));
394 if (t == VR_UNDEFINED || t == VR_VARYING)
395 gcc_assert (min == NULL_TREE && max == NULL_TREE);
397 if (t == VR_UNDEFINED || t == VR_VARYING)
398 gcc_assert (equiv == NULL || bitmap_empty_p (equiv));
405 /* Since updating the equivalence set involves deep copying the
406 bitmaps, only do it if absolutely necessary. */
407 if (vr->equiv == NULL
409 vr->equiv = BITMAP_ALLOC (NULL);
411 if (equiv != vr->equiv)
413 if (equiv && !bitmap_empty_p (equiv))
414 bitmap_copy (vr->equiv, equiv);
416 bitmap_clear (vr->equiv);
421 /* Set value range VR to the canonical form of {T, MIN, MAX, EQUIV}.
422 This means adjusting T, MIN and MAX representing the case of a
423 wrapping range with MAX < MIN covering [MIN, type_max] U [type_min, MAX]
424 as anti-rage ~[MAX+1, MIN-1]. Likewise for wrapping anti-ranges.
425 In corner cases where MAX+1 or MIN-1 wraps this will fall back
427 This routine exists to ease canonicalization in the case where we
428 extract ranges from var + CST op limit. */
431 set_and_canonicalize_value_range (value_range_t *vr, enum value_range_type t,
432 tree min, tree max, bitmap equiv)
434 /* Nothing to canonicalize for symbolic or unknown or varying ranges. */
436 && t != VR_ANTI_RANGE)
437 || TREE_CODE (min) != INTEGER_CST
438 || TREE_CODE (max) != INTEGER_CST)
440 set_value_range (vr, t, min, max, equiv);
444 /* Wrong order for min and max, to swap them and the VR type we need
446 if (tree_int_cst_lt (max, min))
448 tree one = build_int_cst (TREE_TYPE (min), 1);
449 tree tmp = int_const_binop (PLUS_EXPR, max, one, 0);
450 max = int_const_binop (MINUS_EXPR, min, one, 0);
453 /* There's one corner case, if we had [C+1, C] before we now have
454 that again. But this represents an empty value range, so drop
455 to varying in this case. */
456 if (tree_int_cst_lt (max, min))
458 set_value_range_to_varying (vr);
462 t = t == VR_RANGE ? VR_ANTI_RANGE : VR_RANGE;
465 /* Anti-ranges that can be represented as ranges should be so. */
466 if (t == VR_ANTI_RANGE)
468 bool is_min = vrp_val_is_min (min);
469 bool is_max = vrp_val_is_max (max);
471 if (is_min && is_max)
473 /* We cannot deal with empty ranges, drop to varying. */
474 set_value_range_to_varying (vr);
478 /* As a special exception preserve non-null ranges. */
479 && !(TYPE_UNSIGNED (TREE_TYPE (min))
480 && integer_zerop (max)))
482 tree one = build_int_cst (TREE_TYPE (max), 1);
483 min = int_const_binop (PLUS_EXPR, max, one, 0);
484 max = vrp_val_max (TREE_TYPE (max));
489 tree one = build_int_cst (TREE_TYPE (min), 1);
490 max = int_const_binop (MINUS_EXPR, min, one, 0);
491 min = vrp_val_min (TREE_TYPE (min));
496 set_value_range (vr, t, min, max, equiv);
499 /* Copy value range FROM into value range TO. */
502 copy_value_range (value_range_t *to, value_range_t *from)
504 set_value_range (to, from->type, from->min, from->max, from->equiv);
507 /* Set value range VR to a single value. This function is only called
508 with values we get from statements, and exists to clear the
509 TREE_OVERFLOW flag so that we don't think we have an overflow
510 infinity when we shouldn't. */
513 set_value_range_to_value (value_range_t *vr, tree val, bitmap equiv)
515 gcc_assert (is_gimple_min_invariant (val));
516 val = avoid_overflow_infinity (val);
517 set_value_range (vr, VR_RANGE, val, val, equiv);
520 /* Set value range VR to a non-negative range of type TYPE.
521 OVERFLOW_INFINITY indicates whether to use an overflow infinity
522 rather than TYPE_MAX_VALUE; this should be true if we determine
523 that the range is nonnegative based on the assumption that signed
524 overflow does not occur. */
527 set_value_range_to_nonnegative (value_range_t *vr, tree type,
528 bool overflow_infinity)
532 if (overflow_infinity && !supports_overflow_infinity (type))
534 set_value_range_to_varying (vr);
538 zero = build_int_cst (type, 0);
539 set_value_range (vr, VR_RANGE, zero,
541 ? positive_overflow_infinity (type)
542 : TYPE_MAX_VALUE (type)),
546 /* Set value range VR to a non-NULL range of type TYPE. */
549 set_value_range_to_nonnull (value_range_t *vr, tree type)
551 tree zero = build_int_cst (type, 0);
552 set_value_range (vr, VR_ANTI_RANGE, zero, zero, vr->equiv);
556 /* Set value range VR to a NULL range of type TYPE. */
559 set_value_range_to_null (value_range_t *vr, tree type)
561 set_value_range_to_value (vr, build_int_cst (type, 0), vr->equiv);
565 /* Set value range VR to a range of a truthvalue of type TYPE. */
568 set_value_range_to_truthvalue (value_range_t *vr, tree type)
570 if (TYPE_PRECISION (type) == 1)
571 set_value_range_to_varying (vr);
573 set_value_range (vr, VR_RANGE,
574 build_int_cst (type, 0), build_int_cst (type, 1),
579 /* Set value range VR to VR_UNDEFINED. */
582 set_value_range_to_undefined (value_range_t *vr)
584 vr->type = VR_UNDEFINED;
585 vr->min = vr->max = NULL_TREE;
587 bitmap_clear (vr->equiv);
591 /* If abs (min) < abs (max), set VR to [-max, max], if
592 abs (min) >= abs (max), set VR to [-min, min]. */
595 abs_extent_range (value_range_t *vr, tree min, tree max)
599 gcc_assert (TREE_CODE (min) == INTEGER_CST);
600 gcc_assert (TREE_CODE (max) == INTEGER_CST);
601 gcc_assert (INTEGRAL_TYPE_P (TREE_TYPE (min)));
602 gcc_assert (!TYPE_UNSIGNED (TREE_TYPE (min)));
603 min = fold_unary (ABS_EXPR, TREE_TYPE (min), min);
604 max = fold_unary (ABS_EXPR, TREE_TYPE (max), max);
605 if (TREE_OVERFLOW (min) || TREE_OVERFLOW (max))
607 set_value_range_to_varying (vr);
610 cmp = compare_values (min, max);
612 min = fold_unary (NEGATE_EXPR, TREE_TYPE (min), max);
613 else if (cmp == 0 || cmp == 1)
616 min = fold_unary (NEGATE_EXPR, TREE_TYPE (min), min);
620 set_value_range_to_varying (vr);
623 set_and_canonicalize_value_range (vr, VR_RANGE, min, max, NULL);
627 /* Return value range information for VAR.
629 If we have no values ranges recorded (ie, VRP is not running), then
630 return NULL. Otherwise create an empty range if none existed for VAR. */
632 static value_range_t *
633 get_value_range (const_tree var)
637 unsigned ver = SSA_NAME_VERSION (var);
639 /* If we have no recorded ranges, then return NULL. */
647 /* Create a default value range. */
648 vr_value[ver] = vr = XCNEW (value_range_t);
650 /* Defer allocating the equivalence set. */
653 /* If VAR is a default definition, the variable can take any value
655 sym = SSA_NAME_VAR (var);
656 if (SSA_NAME_IS_DEFAULT_DEF (var))
658 /* Try to use the "nonnull" attribute to create ~[0, 0]
659 anti-ranges for pointers. Note that this is only valid with
660 default definitions of PARM_DECLs. */
661 if (TREE_CODE (sym) == PARM_DECL
662 && POINTER_TYPE_P (TREE_TYPE (sym))
663 && nonnull_arg_p (sym))
664 set_value_range_to_nonnull (vr, TREE_TYPE (sym));
666 set_value_range_to_varying (vr);
672 /* Return true, if VAL1 and VAL2 are equal values for VRP purposes. */
675 vrp_operand_equal_p (const_tree val1, const_tree val2)
679 if (!val1 || !val2 || !operand_equal_p (val1, val2, 0))
681 if (is_overflow_infinity (val1))
682 return is_overflow_infinity (val2);
686 /* Return true, if the bitmaps B1 and B2 are equal. */
689 vrp_bitmap_equal_p (const_bitmap b1, const_bitmap b2)
693 && bitmap_equal_p (b1, b2)));
696 /* Update the value range and equivalence set for variable VAR to
697 NEW_VR. Return true if NEW_VR is different from VAR's previous
700 NOTE: This function assumes that NEW_VR is a temporary value range
701 object created for the sole purpose of updating VAR's range. The
702 storage used by the equivalence set from NEW_VR will be freed by
703 this function. Do not call update_value_range when NEW_VR
704 is the range object associated with another SSA name. */
707 update_value_range (const_tree var, value_range_t *new_vr)
709 value_range_t *old_vr;
712 /* Update the value range, if necessary. */
713 old_vr = get_value_range (var);
714 is_new = old_vr->type != new_vr->type
715 || !vrp_operand_equal_p (old_vr->min, new_vr->min)
716 || !vrp_operand_equal_p (old_vr->max, new_vr->max)
717 || !vrp_bitmap_equal_p (old_vr->equiv, new_vr->equiv);
720 set_value_range (old_vr, new_vr->type, new_vr->min, new_vr->max,
723 BITMAP_FREE (new_vr->equiv);
729 /* Add VAR and VAR's equivalence set to EQUIV. This is the central
730 point where equivalence processing can be turned on/off. */
733 add_equivalence (bitmap *equiv, const_tree var)
735 unsigned ver = SSA_NAME_VERSION (var);
736 value_range_t *vr = vr_value[ver];
739 *equiv = BITMAP_ALLOC (NULL);
740 bitmap_set_bit (*equiv, ver);
742 bitmap_ior_into (*equiv, vr->equiv);
746 /* Return true if VR is ~[0, 0]. */
749 range_is_nonnull (value_range_t *vr)
751 return vr->type == VR_ANTI_RANGE
752 && integer_zerop (vr->min)
753 && integer_zerop (vr->max);
757 /* Return true if VR is [0, 0]. */
760 range_is_null (value_range_t *vr)
762 return vr->type == VR_RANGE
763 && integer_zerop (vr->min)
764 && integer_zerop (vr->max);
767 /* Return true if max and min of VR are INTEGER_CST. It's not necessary
771 range_int_cst_p (value_range_t *vr)
773 return (vr->type == VR_RANGE
774 && TREE_CODE (vr->max) == INTEGER_CST
775 && TREE_CODE (vr->min) == INTEGER_CST
776 && !TREE_OVERFLOW (vr->max)
777 && !TREE_OVERFLOW (vr->min));
780 /* Return true if VR is a INTEGER_CST singleton. */
783 range_int_cst_singleton_p (value_range_t *vr)
785 return (range_int_cst_p (vr)
786 && tree_int_cst_equal (vr->min, vr->max));
789 /* Return true if value range VR involves at least one symbol. */
792 symbolic_range_p (value_range_t *vr)
794 return (!is_gimple_min_invariant (vr->min)
795 || !is_gimple_min_invariant (vr->max));
798 /* Return true if value range VR uses an overflow infinity. */
801 overflow_infinity_range_p (value_range_t *vr)
803 return (vr->type == VR_RANGE
804 && (is_overflow_infinity (vr->min)
805 || is_overflow_infinity (vr->max)));
808 /* Return false if we can not make a valid comparison based on VR;
809 this will be the case if it uses an overflow infinity and overflow
810 is not undefined (i.e., -fno-strict-overflow is in effect).
811 Otherwise return true, and set *STRICT_OVERFLOW_P to true if VR
812 uses an overflow infinity. */
815 usable_range_p (value_range_t *vr, bool *strict_overflow_p)
817 gcc_assert (vr->type == VR_RANGE);
818 if (is_overflow_infinity (vr->min))
820 *strict_overflow_p = true;
821 if (!TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (vr->min)))
824 if (is_overflow_infinity (vr->max))
826 *strict_overflow_p = true;
827 if (!TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (vr->max)))
834 /* Like tree_expr_nonnegative_warnv_p, but this function uses value
835 ranges obtained so far. */
838 vrp_expr_computes_nonnegative (tree expr, bool *strict_overflow_p)
840 return (tree_expr_nonnegative_warnv_p (expr, strict_overflow_p)
841 || (TREE_CODE (expr) == SSA_NAME
842 && ssa_name_nonnegative_p (expr)));
845 /* Return true if the result of assignment STMT is know to be non-negative.
846 If the return value is based on the assumption that signed overflow is
847 undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't change
848 *STRICT_OVERFLOW_P.*/
851 gimple_assign_nonnegative_warnv_p (gimple stmt, bool *strict_overflow_p)
853 enum tree_code code = gimple_assign_rhs_code (stmt);
854 switch (get_gimple_rhs_class (code))
856 case GIMPLE_UNARY_RHS:
857 return tree_unary_nonnegative_warnv_p (gimple_assign_rhs_code (stmt),
858 gimple_expr_type (stmt),
859 gimple_assign_rhs1 (stmt),
861 case GIMPLE_BINARY_RHS:
862 return tree_binary_nonnegative_warnv_p (gimple_assign_rhs_code (stmt),
863 gimple_expr_type (stmt),
864 gimple_assign_rhs1 (stmt),
865 gimple_assign_rhs2 (stmt),
867 case GIMPLE_SINGLE_RHS:
868 return tree_single_nonnegative_warnv_p (gimple_assign_rhs1 (stmt),
870 case GIMPLE_INVALID_RHS:
877 /* Return true if return value of call STMT is know to be non-negative.
878 If the return value is based on the assumption that signed overflow is
879 undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't change
880 *STRICT_OVERFLOW_P.*/
883 gimple_call_nonnegative_warnv_p (gimple stmt, bool *strict_overflow_p)
885 tree arg0 = gimple_call_num_args (stmt) > 0 ?
886 gimple_call_arg (stmt, 0) : NULL_TREE;
887 tree arg1 = gimple_call_num_args (stmt) > 1 ?
888 gimple_call_arg (stmt, 1) : NULL_TREE;
890 return tree_call_nonnegative_warnv_p (gimple_expr_type (stmt),
891 gimple_call_fndecl (stmt),
897 /* Return true if STMT is know to to compute a non-negative value.
898 If the return value is based on the assumption that signed overflow is
899 undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't change
900 *STRICT_OVERFLOW_P.*/
903 gimple_stmt_nonnegative_warnv_p (gimple stmt, bool *strict_overflow_p)
905 switch (gimple_code (stmt))
908 return gimple_assign_nonnegative_warnv_p (stmt, strict_overflow_p);
910 return gimple_call_nonnegative_warnv_p (stmt, strict_overflow_p);
916 /* Return true if the result of assignment STMT is know to be non-zero.
917 If the return value is based on the assumption that signed overflow is
918 undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't change
919 *STRICT_OVERFLOW_P.*/
922 gimple_assign_nonzero_warnv_p (gimple stmt, bool *strict_overflow_p)
924 enum tree_code code = gimple_assign_rhs_code (stmt);
925 switch (get_gimple_rhs_class (code))
927 case GIMPLE_UNARY_RHS:
928 return tree_unary_nonzero_warnv_p (gimple_assign_rhs_code (stmt),
929 gimple_expr_type (stmt),
930 gimple_assign_rhs1 (stmt),
932 case GIMPLE_BINARY_RHS:
933 return tree_binary_nonzero_warnv_p (gimple_assign_rhs_code (stmt),
934 gimple_expr_type (stmt),
935 gimple_assign_rhs1 (stmt),
936 gimple_assign_rhs2 (stmt),
938 case GIMPLE_SINGLE_RHS:
939 return tree_single_nonzero_warnv_p (gimple_assign_rhs1 (stmt),
941 case GIMPLE_INVALID_RHS:
948 /* Return true if STMT is know to to compute a non-zero value.
949 If the return value is based on the assumption that signed overflow is
950 undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't change
951 *STRICT_OVERFLOW_P.*/
954 gimple_stmt_nonzero_warnv_p (gimple stmt, bool *strict_overflow_p)
956 switch (gimple_code (stmt))
959 return gimple_assign_nonzero_warnv_p (stmt, strict_overflow_p);
961 return gimple_alloca_call_p (stmt);
967 /* Like tree_expr_nonzero_warnv_p, but this function uses value ranges
971 vrp_stmt_computes_nonzero (gimple stmt, bool *strict_overflow_p)
973 if (gimple_stmt_nonzero_warnv_p (stmt, strict_overflow_p))
976 /* If we have an expression of the form &X->a, then the expression
977 is nonnull if X is nonnull. */
978 if (is_gimple_assign (stmt)
979 && gimple_assign_rhs_code (stmt) == ADDR_EXPR)
981 tree expr = gimple_assign_rhs1 (stmt);
982 tree base = get_base_address (TREE_OPERAND (expr, 0));
984 if (base != NULL_TREE
985 && TREE_CODE (base) == INDIRECT_REF
986 && TREE_CODE (TREE_OPERAND (base, 0)) == SSA_NAME)
988 value_range_t *vr = get_value_range (TREE_OPERAND (base, 0));
989 if (range_is_nonnull (vr))
997 /* Returns true if EXPR is a valid value (as expected by compare_values) --
998 a gimple invariant, or SSA_NAME +- CST. */
1001 valid_value_p (tree expr)
1003 if (TREE_CODE (expr) == SSA_NAME)
1006 if (TREE_CODE (expr) == PLUS_EXPR
1007 || TREE_CODE (expr) == MINUS_EXPR)
1008 return (TREE_CODE (TREE_OPERAND (expr, 0)) == SSA_NAME
1009 && TREE_CODE (TREE_OPERAND (expr, 1)) == INTEGER_CST);
1011 return is_gimple_min_invariant (expr);
1017 -2 if those are incomparable. */
1019 operand_less_p (tree val, tree val2)
1021 /* LT is folded faster than GE and others. Inline the common case. */
1022 if (TREE_CODE (val) == INTEGER_CST && TREE_CODE (val2) == INTEGER_CST)
1024 if (TYPE_UNSIGNED (TREE_TYPE (val)))
1025 return INT_CST_LT_UNSIGNED (val, val2);
1028 if (INT_CST_LT (val, val2))
1036 fold_defer_overflow_warnings ();
1038 tcmp = fold_binary_to_constant (LT_EXPR, boolean_type_node, val, val2);
1040 fold_undefer_and_ignore_overflow_warnings ();
1043 || TREE_CODE (tcmp) != INTEGER_CST)
1046 if (!integer_zerop (tcmp))
1050 /* val >= val2, not considering overflow infinity. */
1051 if (is_negative_overflow_infinity (val))
1052 return is_negative_overflow_infinity (val2) ? 0 : 1;
1053 else if (is_positive_overflow_infinity (val2))
1054 return is_positive_overflow_infinity (val) ? 0 : 1;
1059 /* Compare two values VAL1 and VAL2. Return
1061 -2 if VAL1 and VAL2 cannot be compared at compile-time,
1064 +1 if VAL1 > VAL2, and
1067 This is similar to tree_int_cst_compare but supports pointer values
1068 and values that cannot be compared at compile time.
1070 If STRICT_OVERFLOW_P is not NULL, then set *STRICT_OVERFLOW_P to
1071 true if the return value is only valid if we assume that signed
1072 overflow is undefined. */
1075 compare_values_warnv (tree val1, tree val2, bool *strict_overflow_p)
1080 /* Below we rely on the fact that VAL1 and VAL2 are both pointers or
1082 gcc_assert (POINTER_TYPE_P (TREE_TYPE (val1))
1083 == POINTER_TYPE_P (TREE_TYPE (val2)));
1084 /* Convert the two values into the same type. This is needed because
1085 sizetype causes sign extension even for unsigned types. */
1086 val2 = fold_convert (TREE_TYPE (val1), val2);
1087 STRIP_USELESS_TYPE_CONVERSION (val2);
1089 if ((TREE_CODE (val1) == SSA_NAME
1090 || TREE_CODE (val1) == PLUS_EXPR
1091 || TREE_CODE (val1) == MINUS_EXPR)
1092 && (TREE_CODE (val2) == SSA_NAME
1093 || TREE_CODE (val2) == PLUS_EXPR
1094 || TREE_CODE (val2) == MINUS_EXPR))
1096 tree n1, c1, n2, c2;
1097 enum tree_code code1, code2;
1099 /* If VAL1 and VAL2 are of the form 'NAME [+-] CST' or 'NAME',
1100 return -1 or +1 accordingly. If VAL1 and VAL2 don't use the
1101 same name, return -2. */
1102 if (TREE_CODE (val1) == SSA_NAME)
1110 code1 = TREE_CODE (val1);
1111 n1 = TREE_OPERAND (val1, 0);
1112 c1 = TREE_OPERAND (val1, 1);
1113 if (tree_int_cst_sgn (c1) == -1)
1115 if (is_negative_overflow_infinity (c1))
1117 c1 = fold_unary_to_constant (NEGATE_EXPR, TREE_TYPE (c1), c1);
1120 code1 = code1 == MINUS_EXPR ? PLUS_EXPR : MINUS_EXPR;
1124 if (TREE_CODE (val2) == SSA_NAME)
1132 code2 = TREE_CODE (val2);
1133 n2 = TREE_OPERAND (val2, 0);
1134 c2 = TREE_OPERAND (val2, 1);
1135 if (tree_int_cst_sgn (c2) == -1)
1137 if (is_negative_overflow_infinity (c2))
1139 c2 = fold_unary_to_constant (NEGATE_EXPR, TREE_TYPE (c2), c2);
1142 code2 = code2 == MINUS_EXPR ? PLUS_EXPR : MINUS_EXPR;
1146 /* Both values must use the same name. */
1150 if (code1 == SSA_NAME
1151 && code2 == SSA_NAME)
1155 /* If overflow is defined we cannot simplify more. */
1156 if (!TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (val1)))
1159 if (strict_overflow_p != NULL
1160 && (code1 == SSA_NAME || !TREE_NO_WARNING (val1))
1161 && (code2 == SSA_NAME || !TREE_NO_WARNING (val2)))
1162 *strict_overflow_p = true;
1164 if (code1 == SSA_NAME)
1166 if (code2 == PLUS_EXPR)
1167 /* NAME < NAME + CST */
1169 else if (code2 == MINUS_EXPR)
1170 /* NAME > NAME - CST */
1173 else if (code1 == PLUS_EXPR)
1175 if (code2 == SSA_NAME)
1176 /* NAME + CST > NAME */
1178 else if (code2 == PLUS_EXPR)
1179 /* NAME + CST1 > NAME + CST2, if CST1 > CST2 */
1180 return compare_values_warnv (c1, c2, strict_overflow_p);
1181 else if (code2 == MINUS_EXPR)
1182 /* NAME + CST1 > NAME - CST2 */
1185 else if (code1 == MINUS_EXPR)
1187 if (code2 == SSA_NAME)
1188 /* NAME - CST < NAME */
1190 else if (code2 == PLUS_EXPR)
1191 /* NAME - CST1 < NAME + CST2 */
1193 else if (code2 == MINUS_EXPR)
1194 /* NAME - CST1 > NAME - CST2, if CST1 < CST2. Notice that
1195 C1 and C2 are swapped in the call to compare_values. */
1196 return compare_values_warnv (c2, c1, strict_overflow_p);
1202 /* We cannot compare non-constants. */
1203 if (!is_gimple_min_invariant (val1) || !is_gimple_min_invariant (val2))
1206 if (!POINTER_TYPE_P (TREE_TYPE (val1)))
1208 /* We cannot compare overflowed values, except for overflow
1210 if (TREE_OVERFLOW (val1) || TREE_OVERFLOW (val2))
1212 if (strict_overflow_p != NULL)
1213 *strict_overflow_p = true;
1214 if (is_negative_overflow_infinity (val1))
1215 return is_negative_overflow_infinity (val2) ? 0 : -1;
1216 else if (is_negative_overflow_infinity (val2))
1218 else if (is_positive_overflow_infinity (val1))
1219 return is_positive_overflow_infinity (val2) ? 0 : 1;
1220 else if (is_positive_overflow_infinity (val2))
1225 return tree_int_cst_compare (val1, val2);
1231 /* First see if VAL1 and VAL2 are not the same. */
1232 if (val1 == val2 || operand_equal_p (val1, val2, 0))
1235 /* If VAL1 is a lower address than VAL2, return -1. */
1236 if (operand_less_p (val1, val2) == 1)
1239 /* If VAL1 is a higher address than VAL2, return +1. */
1240 if (operand_less_p (val2, val1) == 1)
1243 /* If VAL1 is different than VAL2, return +2.
1244 For integer constants we either have already returned -1 or 1
1245 or they are equivalent. We still might succeed in proving
1246 something about non-trivial operands. */
1247 if (TREE_CODE (val1) != INTEGER_CST
1248 || TREE_CODE (val2) != INTEGER_CST)
1250 t = fold_binary_to_constant (NE_EXPR, boolean_type_node, val1, val2);
1251 if (t && integer_onep (t))
1259 /* Compare values like compare_values_warnv, but treat comparisons of
1260 nonconstants which rely on undefined overflow as incomparable. */
1263 compare_values (tree val1, tree val2)
1269 ret = compare_values_warnv (val1, val2, &sop);
1271 && (!is_gimple_min_invariant (val1) || !is_gimple_min_invariant (val2)))
1277 /* Return 1 if VAL is inside value range VR (VR->MIN <= VAL <= VR->MAX),
1278 0 if VAL is not inside VR,
1279 -2 if we cannot tell either way.
1281 FIXME, the current semantics of this functions are a bit quirky
1282 when taken in the context of VRP. In here we do not care
1283 about VR's type. If VR is the anti-range ~[3, 5] the call
1284 value_inside_range (4, VR) will return 1.
1286 This is counter-intuitive in a strict sense, but the callers
1287 currently expect this. They are calling the function
1288 merely to determine whether VR->MIN <= VAL <= VR->MAX. The
1289 callers are applying the VR_RANGE/VR_ANTI_RANGE semantics
1292 This also applies to value_ranges_intersect_p and
1293 range_includes_zero_p. The semantics of VR_RANGE and
1294 VR_ANTI_RANGE should be encoded here, but that also means
1295 adapting the users of these functions to the new semantics.
1297 Benchmark compile/20001226-1.c compilation time after changing this
1301 value_inside_range (tree val, value_range_t * vr)
1305 cmp1 = operand_less_p (val, vr->min);
1311 cmp2 = operand_less_p (vr->max, val);
1319 /* Return true if value ranges VR0 and VR1 have a non-empty
1322 Benchmark compile/20001226-1.c compilation time after changing this
1327 value_ranges_intersect_p (value_range_t *vr0, value_range_t *vr1)
1329 /* The value ranges do not intersect if the maximum of the first range is
1330 less than the minimum of the second range or vice versa.
1331 When those relations are unknown, we can't do any better. */
1332 if (operand_less_p (vr0->max, vr1->min) != 0)
1334 if (operand_less_p (vr1->max, vr0->min) != 0)
1340 /* Return true if VR includes the value zero, false otherwise. FIXME,
1341 currently this will return false for an anti-range like ~[-4, 3].
1342 This will be wrong when the semantics of value_inside_range are
1343 modified (currently the users of this function expect these
1347 range_includes_zero_p (value_range_t *vr)
1351 gcc_assert (vr->type != VR_UNDEFINED
1352 && vr->type != VR_VARYING
1353 && !symbolic_range_p (vr));
1355 zero = build_int_cst (TREE_TYPE (vr->min), 0);
1356 return (value_inside_range (zero, vr) == 1);
1359 /* Return true if T, an SSA_NAME, is known to be nonnegative. Return
1360 false otherwise or if no value range information is available. */
1363 ssa_name_nonnegative_p (const_tree t)
1365 value_range_t *vr = get_value_range (t);
1367 if (INTEGRAL_TYPE_P (t)
1368 && TYPE_UNSIGNED (t))
1374 /* Testing for VR_ANTI_RANGE is not useful here as any anti-range
1375 which would return a useful value should be encoded as a VR_RANGE. */
1376 if (vr->type == VR_RANGE)
1378 int result = compare_values (vr->min, integer_zero_node);
1380 return (result == 0 || result == 1);
1385 /* If OP has a value range with a single constant value return that,
1386 otherwise return NULL_TREE. This returns OP itself if OP is a
1390 op_with_constant_singleton_value_range (tree op)
1394 if (is_gimple_min_invariant (op))
1397 if (TREE_CODE (op) != SSA_NAME)
1400 vr = get_value_range (op);
1401 if (vr->type == VR_RANGE
1402 && operand_equal_p (vr->min, vr->max, 0)
1403 && is_gimple_min_invariant (vr->min))
1410 /* Extract value range information from an ASSERT_EXPR EXPR and store
1414 extract_range_from_assert (value_range_t *vr_p, tree expr)
1416 tree var, cond, limit, min, max, type;
1417 value_range_t *var_vr, *limit_vr;
1418 enum tree_code cond_code;
1420 var = ASSERT_EXPR_VAR (expr);
1421 cond = ASSERT_EXPR_COND (expr);
1423 gcc_assert (COMPARISON_CLASS_P (cond));
1425 /* Find VAR in the ASSERT_EXPR conditional. */
1426 if (var == TREE_OPERAND (cond, 0)
1427 || TREE_CODE (TREE_OPERAND (cond, 0)) == PLUS_EXPR
1428 || TREE_CODE (TREE_OPERAND (cond, 0)) == NOP_EXPR)
1430 /* If the predicate is of the form VAR COMP LIMIT, then we just
1431 take LIMIT from the RHS and use the same comparison code. */
1432 cond_code = TREE_CODE (cond);
1433 limit = TREE_OPERAND (cond, 1);
1434 cond = TREE_OPERAND (cond, 0);
1438 /* If the predicate is of the form LIMIT COMP VAR, then we need
1439 to flip around the comparison code to create the proper range
1441 cond_code = swap_tree_comparison (TREE_CODE (cond));
1442 limit = TREE_OPERAND (cond, 0);
1443 cond = TREE_OPERAND (cond, 1);
1446 limit = avoid_overflow_infinity (limit);
1448 type = TREE_TYPE (limit);
1449 gcc_assert (limit != var);
1451 /* For pointer arithmetic, we only keep track of pointer equality
1453 if (POINTER_TYPE_P (type) && cond_code != NE_EXPR && cond_code != EQ_EXPR)
1455 set_value_range_to_varying (vr_p);
1459 /* If LIMIT is another SSA name and LIMIT has a range of its own,
1460 try to use LIMIT's range to avoid creating symbolic ranges
1462 limit_vr = (TREE_CODE (limit) == SSA_NAME) ? get_value_range (limit) : NULL;
1464 /* LIMIT's range is only interesting if it has any useful information. */
1466 && (limit_vr->type == VR_UNDEFINED
1467 || limit_vr->type == VR_VARYING
1468 || symbolic_range_p (limit_vr)))
1471 /* Initially, the new range has the same set of equivalences of
1472 VAR's range. This will be revised before returning the final
1473 value. Since assertions may be chained via mutually exclusive
1474 predicates, we will need to trim the set of equivalences before
1476 gcc_assert (vr_p->equiv == NULL);
1477 add_equivalence (&vr_p->equiv, var);
1479 /* Extract a new range based on the asserted comparison for VAR and
1480 LIMIT's value range. Notice that if LIMIT has an anti-range, we
1481 will only use it for equality comparisons (EQ_EXPR). For any
1482 other kind of assertion, we cannot derive a range from LIMIT's
1483 anti-range that can be used to describe the new range. For
1484 instance, ASSERT_EXPR <x_2, x_2 <= b_4>. If b_4 is ~[2, 10],
1485 then b_4 takes on the ranges [-INF, 1] and [11, +INF]. There is
1486 no single range for x_2 that could describe LE_EXPR, so we might
1487 as well build the range [b_4, +INF] for it.
1488 One special case we handle is extracting a range from a
1489 range test encoded as (unsigned)var + CST <= limit. */
1490 if (TREE_CODE (cond) == NOP_EXPR
1491 || TREE_CODE (cond) == PLUS_EXPR)
1493 if (TREE_CODE (cond) == PLUS_EXPR)
1495 min = fold_build1 (NEGATE_EXPR, TREE_TYPE (TREE_OPERAND (cond, 1)),
1496 TREE_OPERAND (cond, 1));
1497 max = int_const_binop (PLUS_EXPR, limit, min, 0);
1498 cond = TREE_OPERAND (cond, 0);
1502 min = build_int_cst (TREE_TYPE (var), 0);
1506 /* Make sure to not set TREE_OVERFLOW on the final type
1507 conversion. We are willingly interpreting large positive
1508 unsigned values as negative singed values here. */
1509 min = force_fit_type_double (TREE_TYPE (var), TREE_INT_CST_LOW (min),
1510 TREE_INT_CST_HIGH (min), 0, false);
1511 max = force_fit_type_double (TREE_TYPE (var), TREE_INT_CST_LOW (max),
1512 TREE_INT_CST_HIGH (max), 0, false);
1514 /* We can transform a max, min range to an anti-range or
1515 vice-versa. Use set_and_canonicalize_value_range which does
1517 if (cond_code == LE_EXPR)
1518 set_and_canonicalize_value_range (vr_p, VR_RANGE,
1519 min, max, vr_p->equiv);
1520 else if (cond_code == GT_EXPR)
1521 set_and_canonicalize_value_range (vr_p, VR_ANTI_RANGE,
1522 min, max, vr_p->equiv);
1526 else if (cond_code == EQ_EXPR)
1528 enum value_range_type range_type;
1532 range_type = limit_vr->type;
1533 min = limit_vr->min;
1534 max = limit_vr->max;
1538 range_type = VR_RANGE;
1543 set_value_range (vr_p, range_type, min, max, vr_p->equiv);
1545 /* When asserting the equality VAR == LIMIT and LIMIT is another
1546 SSA name, the new range will also inherit the equivalence set
1548 if (TREE_CODE (limit) == SSA_NAME)
1549 add_equivalence (&vr_p->equiv, limit);
1551 else if (cond_code == NE_EXPR)
1553 /* As described above, when LIMIT's range is an anti-range and
1554 this assertion is an inequality (NE_EXPR), then we cannot
1555 derive anything from the anti-range. For instance, if
1556 LIMIT's range was ~[0, 0], the assertion 'VAR != LIMIT' does
1557 not imply that VAR's range is [0, 0]. So, in the case of
1558 anti-ranges, we just assert the inequality using LIMIT and
1561 If LIMIT_VR is a range, we can only use it to build a new
1562 anti-range if LIMIT_VR is a single-valued range. For
1563 instance, if LIMIT_VR is [0, 1], the predicate
1564 VAR != [0, 1] does not mean that VAR's range is ~[0, 1].
1565 Rather, it means that for value 0 VAR should be ~[0, 0]
1566 and for value 1, VAR should be ~[1, 1]. We cannot
1567 represent these ranges.
1569 The only situation in which we can build a valid
1570 anti-range is when LIMIT_VR is a single-valued range
1571 (i.e., LIMIT_VR->MIN == LIMIT_VR->MAX). In that case,
1572 build the anti-range ~[LIMIT_VR->MIN, LIMIT_VR->MAX]. */
1574 && limit_vr->type == VR_RANGE
1575 && compare_values (limit_vr->min, limit_vr->max) == 0)
1577 min = limit_vr->min;
1578 max = limit_vr->max;
1582 /* In any other case, we cannot use LIMIT's range to build a
1583 valid anti-range. */
1587 /* If MIN and MAX cover the whole range for their type, then
1588 just use the original LIMIT. */
1589 if (INTEGRAL_TYPE_P (type)
1590 && vrp_val_is_min (min)
1591 && vrp_val_is_max (max))
1594 set_value_range (vr_p, VR_ANTI_RANGE, min, max, vr_p->equiv);
1596 else if (cond_code == LE_EXPR || cond_code == LT_EXPR)
1598 min = TYPE_MIN_VALUE (type);
1600 if (limit_vr == NULL || limit_vr->type == VR_ANTI_RANGE)
1604 /* If LIMIT_VR is of the form [N1, N2], we need to build the
1605 range [MIN, N2] for LE_EXPR and [MIN, N2 - 1] for
1607 max = limit_vr->max;
1610 /* If the maximum value forces us to be out of bounds, simply punt.
1611 It would be pointless to try and do anything more since this
1612 all should be optimized away above us. */
1613 if ((cond_code == LT_EXPR
1614 && compare_values (max, min) == 0)
1615 || (CONSTANT_CLASS_P (max) && TREE_OVERFLOW (max)))
1616 set_value_range_to_varying (vr_p);
1619 /* For LT_EXPR, we create the range [MIN, MAX - 1]. */
1620 if (cond_code == LT_EXPR)
1622 tree one = build_int_cst (type, 1);
1623 max = fold_build2 (MINUS_EXPR, type, max, one);
1625 TREE_NO_WARNING (max) = 1;
1628 set_value_range (vr_p, VR_RANGE, min, max, vr_p->equiv);
1631 else if (cond_code == GE_EXPR || cond_code == GT_EXPR)
1633 max = TYPE_MAX_VALUE (type);
1635 if (limit_vr == NULL || limit_vr->type == VR_ANTI_RANGE)
1639 /* If LIMIT_VR is of the form [N1, N2], we need to build the
1640 range [N1, MAX] for GE_EXPR and [N1 + 1, MAX] for
1642 min = limit_vr->min;
1645 /* If the minimum value forces us to be out of bounds, simply punt.
1646 It would be pointless to try and do anything more since this
1647 all should be optimized away above us. */
1648 if ((cond_code == GT_EXPR
1649 && compare_values (min, max) == 0)
1650 || (CONSTANT_CLASS_P (min) && TREE_OVERFLOW (min)))
1651 set_value_range_to_varying (vr_p);
1654 /* For GT_EXPR, we create the range [MIN + 1, MAX]. */
1655 if (cond_code == GT_EXPR)
1657 tree one = build_int_cst (type, 1);
1658 min = fold_build2 (PLUS_EXPR, type, min, one);
1660 TREE_NO_WARNING (min) = 1;
1663 set_value_range (vr_p, VR_RANGE, min, max, vr_p->equiv);
1669 /* If VAR already had a known range, it may happen that the new
1670 range we have computed and VAR's range are not compatible. For
1674 p_6 = ASSERT_EXPR <p_5, p_5 == NULL>;
1676 p_8 = ASSERT_EXPR <p_6, p_6 != NULL>;
1678 While the above comes from a faulty program, it will cause an ICE
1679 later because p_8 and p_6 will have incompatible ranges and at
1680 the same time will be considered equivalent. A similar situation
1684 i_6 = ASSERT_EXPR <i_5, i_5 > 10>;
1686 i_7 = ASSERT_EXPR <i_6, i_6 < 5>;
1688 Again i_6 and i_7 will have incompatible ranges. It would be
1689 pointless to try and do anything with i_7's range because
1690 anything dominated by 'if (i_5 < 5)' will be optimized away.
1691 Note, due to the wa in which simulation proceeds, the statement
1692 i_7 = ASSERT_EXPR <...> we would never be visited because the
1693 conditional 'if (i_5 < 5)' always evaluates to false. However,
1694 this extra check does not hurt and may protect against future
1695 changes to VRP that may get into a situation similar to the
1696 NULL pointer dereference example.
1698 Note that these compatibility tests are only needed when dealing
1699 with ranges or a mix of range and anti-range. If VAR_VR and VR_P
1700 are both anti-ranges, they will always be compatible, because two
1701 anti-ranges will always have a non-empty intersection. */
1703 var_vr = get_value_range (var);
1705 /* We may need to make adjustments when VR_P and VAR_VR are numeric
1706 ranges or anti-ranges. */
1707 if (vr_p->type == VR_VARYING
1708 || vr_p->type == VR_UNDEFINED
1709 || var_vr->type == VR_VARYING
1710 || var_vr->type == VR_UNDEFINED
1711 || symbolic_range_p (vr_p)
1712 || symbolic_range_p (var_vr))
1715 if (var_vr->type == VR_RANGE && vr_p->type == VR_RANGE)
1717 /* If the two ranges have a non-empty intersection, we can
1718 refine the resulting range. Since the assert expression
1719 creates an equivalency and at the same time it asserts a
1720 predicate, we can take the intersection of the two ranges to
1721 get better precision. */
1722 if (value_ranges_intersect_p (var_vr, vr_p))
1724 /* Use the larger of the two minimums. */
1725 if (compare_values (vr_p->min, var_vr->min) == -1)
1730 /* Use the smaller of the two maximums. */
1731 if (compare_values (vr_p->max, var_vr->max) == 1)
1736 set_value_range (vr_p, vr_p->type, min, max, vr_p->equiv);
1740 /* The two ranges do not intersect, set the new range to
1741 VARYING, because we will not be able to do anything
1742 meaningful with it. */
1743 set_value_range_to_varying (vr_p);
1746 else if ((var_vr->type == VR_RANGE && vr_p->type == VR_ANTI_RANGE)
1747 || (var_vr->type == VR_ANTI_RANGE && vr_p->type == VR_RANGE))
1749 /* A range and an anti-range will cancel each other only if
1750 their ends are the same. For instance, in the example above,
1751 p_8's range ~[0, 0] and p_6's range [0, 0] are incompatible,
1752 so VR_P should be set to VR_VARYING. */
1753 if (compare_values (var_vr->min, vr_p->min) == 0
1754 && compare_values (var_vr->max, vr_p->max) == 0)
1755 set_value_range_to_varying (vr_p);
1758 tree min, max, anti_min, anti_max, real_min, real_max;
1761 /* We want to compute the logical AND of the two ranges;
1762 there are three cases to consider.
1765 1. The VR_ANTI_RANGE range is completely within the
1766 VR_RANGE and the endpoints of the ranges are
1767 different. In that case the resulting range
1768 should be whichever range is more precise.
1769 Typically that will be the VR_RANGE.
1771 2. The VR_ANTI_RANGE is completely disjoint from
1772 the VR_RANGE. In this case the resulting range
1773 should be the VR_RANGE.
1775 3. There is some overlap between the VR_ANTI_RANGE
1778 3a. If the high limit of the VR_ANTI_RANGE resides
1779 within the VR_RANGE, then the result is a new
1780 VR_RANGE starting at the high limit of the
1781 VR_ANTI_RANGE + 1 and extending to the
1782 high limit of the original VR_RANGE.
1784 3b. If the low limit of the VR_ANTI_RANGE resides
1785 within the VR_RANGE, then the result is a new
1786 VR_RANGE starting at the low limit of the original
1787 VR_RANGE and extending to the low limit of the
1788 VR_ANTI_RANGE - 1. */
1789 if (vr_p->type == VR_ANTI_RANGE)
1791 anti_min = vr_p->min;
1792 anti_max = vr_p->max;
1793 real_min = var_vr->min;
1794 real_max = var_vr->max;
1798 anti_min = var_vr->min;
1799 anti_max = var_vr->max;
1800 real_min = vr_p->min;
1801 real_max = vr_p->max;
1805 /* Case 1, VR_ANTI_RANGE completely within VR_RANGE,
1806 not including any endpoints. */
1807 if (compare_values (anti_max, real_max) == -1
1808 && compare_values (anti_min, real_min) == 1)
1810 /* If the range is covering the whole valid range of
1811 the type keep the anti-range. */
1812 if (!vrp_val_is_min (real_min)
1813 || !vrp_val_is_max (real_max))
1814 set_value_range (vr_p, VR_RANGE, real_min,
1815 real_max, vr_p->equiv);
1817 /* Case 2, VR_ANTI_RANGE completely disjoint from
1819 else if (compare_values (anti_min, real_max) == 1
1820 || compare_values (anti_max, real_min) == -1)
1822 set_value_range (vr_p, VR_RANGE, real_min,
1823 real_max, vr_p->equiv);
1825 /* Case 3a, the anti-range extends into the low
1826 part of the real range. Thus creating a new
1827 low for the real range. */
1828 else if (((cmp = compare_values (anti_max, real_min)) == 1
1830 && compare_values (anti_max, real_max) == -1)
1832 gcc_assert (!is_positive_overflow_infinity (anti_max));
1833 if (needs_overflow_infinity (TREE_TYPE (anti_max))
1834 && vrp_val_is_max (anti_max))
1836 if (!supports_overflow_infinity (TREE_TYPE (var_vr->min)))
1838 set_value_range_to_varying (vr_p);
1841 min = positive_overflow_infinity (TREE_TYPE (var_vr->min));
1843 else if (!POINTER_TYPE_P (TREE_TYPE (var_vr->min)))
1844 min = fold_build2 (PLUS_EXPR, TREE_TYPE (var_vr->min),
1846 build_int_cst (TREE_TYPE (var_vr->min), 1));
1848 min = fold_build2 (POINTER_PLUS_EXPR, TREE_TYPE (var_vr->min),
1849 anti_max, size_int (1));
1851 set_value_range (vr_p, VR_RANGE, min, max, vr_p->equiv);
1853 /* Case 3b, the anti-range extends into the high
1854 part of the real range. Thus creating a new
1855 higher for the real range. */
1856 else if (compare_values (anti_min, real_min) == 1
1857 && ((cmp = compare_values (anti_min, real_max)) == -1
1860 gcc_assert (!is_negative_overflow_infinity (anti_min));
1861 if (needs_overflow_infinity (TREE_TYPE (anti_min))
1862 && vrp_val_is_min (anti_min))
1864 if (!supports_overflow_infinity (TREE_TYPE (var_vr->min)))
1866 set_value_range_to_varying (vr_p);
1869 max = negative_overflow_infinity (TREE_TYPE (var_vr->min));
1871 else if (!POINTER_TYPE_P (TREE_TYPE (var_vr->min)))
1872 max = fold_build2 (MINUS_EXPR, TREE_TYPE (var_vr->min),
1874 build_int_cst (TREE_TYPE (var_vr->min), 1));
1876 max = fold_build2 (POINTER_PLUS_EXPR, TREE_TYPE (var_vr->min),
1880 set_value_range (vr_p, VR_RANGE, min, max, vr_p->equiv);
1887 /* Extract range information from SSA name VAR and store it in VR. If
1888 VAR has an interesting range, use it. Otherwise, create the
1889 range [VAR, VAR] and return it. This is useful in situations where
1890 we may have conditionals testing values of VARYING names. For
1897 Even if y_5 is deemed VARYING, we can determine that x_3 > y_5 is
1901 extract_range_from_ssa_name (value_range_t *vr, tree var)
1903 value_range_t *var_vr = get_value_range (var);
1905 if (var_vr->type != VR_UNDEFINED && var_vr->type != VR_VARYING)
1906 copy_value_range (vr, var_vr);
1908 set_value_range (vr, VR_RANGE, var, var, NULL);
1910 add_equivalence (&vr->equiv, var);
1914 /* Wrapper around int_const_binop. If the operation overflows and we
1915 are not using wrapping arithmetic, then adjust the result to be
1916 -INF or +INF depending on CODE, VAL1 and VAL2. This can return
1917 NULL_TREE if we need to use an overflow infinity representation but
1918 the type does not support it. */
1921 vrp_int_const_binop (enum tree_code code, tree val1, tree val2)
1925 res = int_const_binop (code, val1, val2, 0);
1927 /* If we are using unsigned arithmetic, operate symbolically
1928 on -INF and +INF as int_const_binop only handles signed overflow. */
1929 if (TYPE_UNSIGNED (TREE_TYPE (val1)))
1931 int checkz = compare_values (res, val1);
1932 bool overflow = false;
1934 /* Ensure that res = val1 [+*] val2 >= val1
1935 or that res = val1 - val2 <= val1. */
1936 if ((code == PLUS_EXPR
1937 && !(checkz == 1 || checkz == 0))
1938 || (code == MINUS_EXPR
1939 && !(checkz == 0 || checkz == -1)))
1943 /* Checking for multiplication overflow is done by dividing the
1944 output of the multiplication by the first input of the
1945 multiplication. If the result of that division operation is
1946 not equal to the second input of the multiplication, then the
1947 multiplication overflowed. */
1948 else if (code == MULT_EXPR && !integer_zerop (val1))
1950 tree tmp = int_const_binop (TRUNC_DIV_EXPR,
1953 int check = compare_values (tmp, val2);
1961 res = copy_node (res);
1962 TREE_OVERFLOW (res) = 1;
1966 else if (TYPE_OVERFLOW_WRAPS (TREE_TYPE (val1)))
1967 /* If the singed operation wraps then int_const_binop has done
1968 everything we want. */
1970 else if ((TREE_OVERFLOW (res)
1971 && !TREE_OVERFLOW (val1)
1972 && !TREE_OVERFLOW (val2))
1973 || is_overflow_infinity (val1)
1974 || is_overflow_infinity (val2))
1976 /* If the operation overflowed but neither VAL1 nor VAL2 are
1977 overflown, return -INF or +INF depending on the operation
1978 and the combination of signs of the operands. */
1979 int sgn1 = tree_int_cst_sgn (val1);
1980 int sgn2 = tree_int_cst_sgn (val2);
1982 if (needs_overflow_infinity (TREE_TYPE (res))
1983 && !supports_overflow_infinity (TREE_TYPE (res)))
1986 /* We have to punt on adding infinities of different signs,
1987 since we can't tell what the sign of the result should be.
1988 Likewise for subtracting infinities of the same sign. */
1989 if (((code == PLUS_EXPR && sgn1 != sgn2)
1990 || (code == MINUS_EXPR && sgn1 == sgn2))
1991 && is_overflow_infinity (val1)
1992 && is_overflow_infinity (val2))
1995 /* Don't try to handle division or shifting of infinities. */
1996 if ((code == TRUNC_DIV_EXPR
1997 || code == FLOOR_DIV_EXPR
1998 || code == CEIL_DIV_EXPR
1999 || code == EXACT_DIV_EXPR
2000 || code == ROUND_DIV_EXPR
2001 || code == RSHIFT_EXPR)
2002 && (is_overflow_infinity (val1)
2003 || is_overflow_infinity (val2)))
2006 /* Notice that we only need to handle the restricted set of
2007 operations handled by extract_range_from_binary_expr.
2008 Among them, only multiplication, addition and subtraction
2009 can yield overflow without overflown operands because we
2010 are working with integral types only... except in the
2011 case VAL1 = -INF and VAL2 = -1 which overflows to +INF
2012 for division too. */
2014 /* For multiplication, the sign of the overflow is given
2015 by the comparison of the signs of the operands. */
2016 if ((code == MULT_EXPR && sgn1 == sgn2)
2017 /* For addition, the operands must be of the same sign
2018 to yield an overflow. Its sign is therefore that
2019 of one of the operands, for example the first. For
2020 infinite operands X + -INF is negative, not positive. */
2021 || (code == PLUS_EXPR
2023 ? !is_negative_overflow_infinity (val2)
2024 : is_positive_overflow_infinity (val2)))
2025 /* For subtraction, non-infinite operands must be of
2026 different signs to yield an overflow. Its sign is
2027 therefore that of the first operand or the opposite of
2028 that of the second operand. A first operand of 0 counts
2029 as positive here, for the corner case 0 - (-INF), which
2030 overflows, but must yield +INF. For infinite operands 0
2031 - INF is negative, not positive. */
2032 || (code == MINUS_EXPR
2034 ? !is_positive_overflow_infinity (val2)
2035 : is_negative_overflow_infinity (val2)))
2036 /* We only get in here with positive shift count, so the
2037 overflow direction is the same as the sign of val1.
2038 Actually rshift does not overflow at all, but we only
2039 handle the case of shifting overflowed -INF and +INF. */
2040 || (code == RSHIFT_EXPR
2042 /* For division, the only case is -INF / -1 = +INF. */
2043 || code == TRUNC_DIV_EXPR
2044 || code == FLOOR_DIV_EXPR
2045 || code == CEIL_DIV_EXPR
2046 || code == EXACT_DIV_EXPR
2047 || code == ROUND_DIV_EXPR)
2048 return (needs_overflow_infinity (TREE_TYPE (res))
2049 ? positive_overflow_infinity (TREE_TYPE (res))
2050 : TYPE_MAX_VALUE (TREE_TYPE (res)));
2052 return (needs_overflow_infinity (TREE_TYPE (res))
2053 ? negative_overflow_infinity (TREE_TYPE (res))
2054 : TYPE_MIN_VALUE (TREE_TYPE (res)));
2061 /* Extract range information from a binary expression EXPR based on
2062 the ranges of each of its operands and the expression code. */
2065 extract_range_from_binary_expr (value_range_t *vr,
2066 enum tree_code code,
2067 tree expr_type, tree op0, tree op1)
2069 enum value_range_type type;
2072 value_range_t vr0 = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
2073 value_range_t vr1 = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
2075 /* Not all binary expressions can be applied to ranges in a
2076 meaningful way. Handle only arithmetic operations. */
2077 if (code != PLUS_EXPR
2078 && code != MINUS_EXPR
2079 && code != POINTER_PLUS_EXPR
2080 && code != MULT_EXPR
2081 && code != TRUNC_DIV_EXPR
2082 && code != FLOOR_DIV_EXPR
2083 && code != CEIL_DIV_EXPR
2084 && code != EXACT_DIV_EXPR
2085 && code != ROUND_DIV_EXPR
2086 && code != TRUNC_MOD_EXPR
2087 && code != FLOOR_MOD_EXPR
2088 && code != CEIL_MOD_EXPR
2089 && code != ROUND_MOD_EXPR
2090 && code != RSHIFT_EXPR
2093 && code != BIT_AND_EXPR
2094 && code != BIT_IOR_EXPR
2095 && code != TRUTH_AND_EXPR
2096 && code != TRUTH_OR_EXPR)
2098 /* We can still do constant propagation here. */
2099 tree const_op0 = op_with_constant_singleton_value_range (op0);
2100 tree const_op1 = op_with_constant_singleton_value_range (op1);
2101 if (const_op0 || const_op1)
2103 tree tem = fold_binary (code, expr_type,
2104 const_op0 ? const_op0 : op0,
2105 const_op1 ? const_op1 : op1);
2107 && is_gimple_min_invariant (tem)
2108 && !is_overflow_infinity (tem))
2110 set_value_range (vr, VR_RANGE, tem, tem, NULL);
2114 set_value_range_to_varying (vr);
2118 /* Get value ranges for each operand. For constant operands, create
2119 a new value range with the operand to simplify processing. */
2120 if (TREE_CODE (op0) == SSA_NAME)
2121 vr0 = *(get_value_range (op0));
2122 else if (is_gimple_min_invariant (op0))
2123 set_value_range_to_value (&vr0, op0, NULL);
2125 set_value_range_to_varying (&vr0);
2127 if (TREE_CODE (op1) == SSA_NAME)
2128 vr1 = *(get_value_range (op1));
2129 else if (is_gimple_min_invariant (op1))
2130 set_value_range_to_value (&vr1, op1, NULL);
2132 set_value_range_to_varying (&vr1);
2134 /* If either range is UNDEFINED, so is the result. */
2135 if (vr0.type == VR_UNDEFINED || vr1.type == VR_UNDEFINED)
2137 set_value_range_to_undefined (vr);
2141 /* The type of the resulting value range defaults to VR0.TYPE. */
2144 /* Refuse to operate on VARYING ranges, ranges of different kinds
2145 and symbolic ranges. As an exception, we allow BIT_AND_EXPR
2146 because we may be able to derive a useful range even if one of
2147 the operands is VR_VARYING or symbolic range. Similarly for
2148 divisions. TODO, we may be able to derive anti-ranges in
2150 if (code != BIT_AND_EXPR
2151 && code != TRUTH_AND_EXPR
2152 && code != TRUTH_OR_EXPR
2153 && code != TRUNC_DIV_EXPR
2154 && code != FLOOR_DIV_EXPR
2155 && code != CEIL_DIV_EXPR
2156 && code != EXACT_DIV_EXPR
2157 && code != ROUND_DIV_EXPR
2158 && code != TRUNC_MOD_EXPR
2159 && code != FLOOR_MOD_EXPR
2160 && code != CEIL_MOD_EXPR
2161 && code != ROUND_MOD_EXPR
2162 && (vr0.type == VR_VARYING
2163 || vr1.type == VR_VARYING
2164 || vr0.type != vr1.type
2165 || symbolic_range_p (&vr0)
2166 || symbolic_range_p (&vr1)))
2168 set_value_range_to_varying (vr);
2172 /* Now evaluate the expression to determine the new range. */
2173 if (POINTER_TYPE_P (expr_type)
2174 || POINTER_TYPE_P (TREE_TYPE (op0))
2175 || POINTER_TYPE_P (TREE_TYPE (op1)))
2177 if (code == MIN_EXPR || code == MAX_EXPR)
2179 /* For MIN/MAX expressions with pointers, we only care about
2180 nullness, if both are non null, then the result is nonnull.
2181 If both are null, then the result is null. Otherwise they
2183 if (range_is_nonnull (&vr0) && range_is_nonnull (&vr1))
2184 set_value_range_to_nonnull (vr, expr_type);
2185 else if (range_is_null (&vr0) && range_is_null (&vr1))
2186 set_value_range_to_null (vr, expr_type);
2188 set_value_range_to_varying (vr);
2192 gcc_assert (code == POINTER_PLUS_EXPR);
2193 /* For pointer types, we are really only interested in asserting
2194 whether the expression evaluates to non-NULL. */
2195 if (range_is_nonnull (&vr0) || range_is_nonnull (&vr1))
2196 set_value_range_to_nonnull (vr, expr_type);
2197 else if (range_is_null (&vr0) && range_is_null (&vr1))
2198 set_value_range_to_null (vr, expr_type);
2200 set_value_range_to_varying (vr);
2205 /* For integer ranges, apply the operation to each end of the
2206 range and see what we end up with. */
2207 if (code == TRUTH_AND_EXPR
2208 || code == TRUTH_OR_EXPR)
2210 /* If one of the operands is zero, we know that the whole
2211 expression evaluates zero. */
2212 if (code == TRUTH_AND_EXPR
2213 && ((vr0.type == VR_RANGE
2214 && integer_zerop (vr0.min)
2215 && integer_zerop (vr0.max))
2216 || (vr1.type == VR_RANGE
2217 && integer_zerop (vr1.min)
2218 && integer_zerop (vr1.max))))
2221 min = max = build_int_cst (expr_type, 0);
2223 /* If one of the operands is one, we know that the whole
2224 expression evaluates one. */
2225 else if (code == TRUTH_OR_EXPR
2226 && ((vr0.type == VR_RANGE
2227 && integer_onep (vr0.min)
2228 && integer_onep (vr0.max))
2229 || (vr1.type == VR_RANGE
2230 && integer_onep (vr1.min)
2231 && integer_onep (vr1.max))))
2234 min = max = build_int_cst (expr_type, 1);
2236 else if (vr0.type != VR_VARYING
2237 && vr1.type != VR_VARYING
2238 && vr0.type == vr1.type
2239 && !symbolic_range_p (&vr0)
2240 && !overflow_infinity_range_p (&vr0)
2241 && !symbolic_range_p (&vr1)
2242 && !overflow_infinity_range_p (&vr1))
2244 /* Boolean expressions cannot be folded with int_const_binop. */
2245 min = fold_binary (code, expr_type, vr0.min, vr1.min);
2246 max = fold_binary (code, expr_type, vr0.max, vr1.max);
2250 /* The result of a TRUTH_*_EXPR is always true or false. */
2251 set_value_range_to_truthvalue (vr, expr_type);
2255 else if (code == PLUS_EXPR
2257 || code == MAX_EXPR)
2259 /* If we have a PLUS_EXPR with two VR_ANTI_RANGEs, drop to
2260 VR_VARYING. It would take more effort to compute a precise
2261 range for such a case. For example, if we have op0 == 1 and
2262 op1 == -1 with their ranges both being ~[0,0], we would have
2263 op0 + op1 == 0, so we cannot claim that the sum is in ~[0,0].
2264 Note that we are guaranteed to have vr0.type == vr1.type at
2266 if (code == PLUS_EXPR && vr0.type == VR_ANTI_RANGE)
2268 set_value_range_to_varying (vr);
2272 /* For operations that make the resulting range directly
2273 proportional to the original ranges, apply the operation to
2274 the same end of each range. */
2275 min = vrp_int_const_binop (code, vr0.min, vr1.min);
2276 max = vrp_int_const_binop (code, vr0.max, vr1.max);
2278 /* If both additions overflowed the range kind is still correct.
2279 This happens regularly with subtracting something in unsigned
2281 ??? See PR30318 for all the cases we do not handle. */
2282 if (code == PLUS_EXPR
2283 && (TREE_OVERFLOW (min) && !is_overflow_infinity (min))
2284 && (TREE_OVERFLOW (max) && !is_overflow_infinity (max)))
2286 min = build_int_cst_wide (TREE_TYPE (min),
2287 TREE_INT_CST_LOW (min),
2288 TREE_INT_CST_HIGH (min));
2289 max = build_int_cst_wide (TREE_TYPE (max),
2290 TREE_INT_CST_LOW (max),
2291 TREE_INT_CST_HIGH (max));
2294 else if (code == MULT_EXPR
2295 || code == TRUNC_DIV_EXPR
2296 || code == FLOOR_DIV_EXPR
2297 || code == CEIL_DIV_EXPR
2298 || code == EXACT_DIV_EXPR
2299 || code == ROUND_DIV_EXPR
2300 || code == RSHIFT_EXPR)
2306 /* If we have an unsigned MULT_EXPR with two VR_ANTI_RANGEs,
2307 drop to VR_VARYING. It would take more effort to compute a
2308 precise range for such a case. For example, if we have
2309 op0 == 65536 and op1 == 65536 with their ranges both being
2310 ~[0,0] on a 32-bit machine, we would have op0 * op1 == 0, so
2311 we cannot claim that the product is in ~[0,0]. Note that we
2312 are guaranteed to have vr0.type == vr1.type at this
2314 if (code == MULT_EXPR
2315 && vr0.type == VR_ANTI_RANGE
2316 && !TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (op0)))
2318 set_value_range_to_varying (vr);
2322 /* If we have a RSHIFT_EXPR with any shift values outside [0..prec-1],
2323 then drop to VR_VARYING. Outside of this range we get undefined
2324 behavior from the shift operation. We cannot even trust
2325 SHIFT_COUNT_TRUNCATED at this stage, because that applies to rtl
2326 shifts, and the operation at the tree level may be widened. */
2327 if (code == RSHIFT_EXPR)
2329 if (vr1.type == VR_ANTI_RANGE
2330 || !vrp_expr_computes_nonnegative (op1, &sop)
2332 (build_int_cst (TREE_TYPE (vr1.max),
2333 TYPE_PRECISION (expr_type) - 1),
2336 set_value_range_to_varying (vr);
2341 else if ((code == TRUNC_DIV_EXPR
2342 || code == FLOOR_DIV_EXPR
2343 || code == CEIL_DIV_EXPR
2344 || code == EXACT_DIV_EXPR
2345 || code == ROUND_DIV_EXPR)
2346 && (vr0.type != VR_RANGE || symbolic_range_p (&vr0)))
2348 /* For division, if op1 has VR_RANGE but op0 does not, something
2349 can be deduced just from that range. Say [min, max] / [4, max]
2350 gives [min / 4, max / 4] range. */
2351 if (vr1.type == VR_RANGE
2352 && !symbolic_range_p (&vr1)
2353 && !range_includes_zero_p (&vr1))
2355 vr0.type = type = VR_RANGE;
2356 vr0.min = vrp_val_min (TREE_TYPE (op0));
2357 vr0.max = vrp_val_max (TREE_TYPE (op1));
2361 set_value_range_to_varying (vr);
2366 /* For divisions, if op0 is VR_RANGE, we can deduce a range
2367 even if op1 is VR_VARYING, VR_ANTI_RANGE, symbolic or can
2369 if ((code == TRUNC_DIV_EXPR
2370 || code == FLOOR_DIV_EXPR
2371 || code == CEIL_DIV_EXPR
2372 || code == EXACT_DIV_EXPR
2373 || code == ROUND_DIV_EXPR)
2374 && vr0.type == VR_RANGE
2375 && (vr1.type != VR_RANGE
2376 || symbolic_range_p (&vr1)
2377 || range_includes_zero_p (&vr1)))
2379 tree zero = build_int_cst (TREE_TYPE (vr0.min), 0);
2385 if (vrp_expr_computes_nonnegative (op1, &sop) && !sop)
2387 /* For unsigned division or when divisor is known
2388 to be non-negative, the range has to cover
2389 all numbers from 0 to max for positive max
2390 and all numbers from min to 0 for negative min. */
2391 cmp = compare_values (vr0.max, zero);
2394 else if (cmp == 0 || cmp == 1)
2398 cmp = compare_values (vr0.min, zero);
2401 else if (cmp == 0 || cmp == -1)
2408 /* Otherwise the range is -max .. max or min .. -min
2409 depending on which bound is bigger in absolute value,
2410 as the division can change the sign. */
2411 abs_extent_range (vr, vr0.min, vr0.max);
2414 if (type == VR_VARYING)
2416 set_value_range_to_varying (vr);
2421 /* Multiplications and divisions are a bit tricky to handle,
2422 depending on the mix of signs we have in the two ranges, we
2423 need to operate on different values to get the minimum and
2424 maximum values for the new range. One approach is to figure
2425 out all the variations of range combinations and do the
2428 However, this involves several calls to compare_values and it
2429 is pretty convoluted. It's simpler to do the 4 operations
2430 (MIN0 OP MIN1, MIN0 OP MAX1, MAX0 OP MIN1 and MAX0 OP MAX0 OP
2431 MAX1) and then figure the smallest and largest values to form
2435 gcc_assert ((vr0.type == VR_RANGE
2436 || (code == MULT_EXPR && vr0.type == VR_ANTI_RANGE))
2437 && vr0.type == vr1.type);
2439 /* Compute the 4 cross operations. */
2441 val[0] = vrp_int_const_binop (code, vr0.min, vr1.min);
2442 if (val[0] == NULL_TREE)
2445 if (vr1.max == vr1.min)
2449 val[1] = vrp_int_const_binop (code, vr0.min, vr1.max);
2450 if (val[1] == NULL_TREE)
2454 if (vr0.max == vr0.min)
2458 val[2] = vrp_int_const_binop (code, vr0.max, vr1.min);
2459 if (val[2] == NULL_TREE)
2463 if (vr0.min == vr0.max || vr1.min == vr1.max)
2467 val[3] = vrp_int_const_binop (code, vr0.max, vr1.max);
2468 if (val[3] == NULL_TREE)
2474 set_value_range_to_varying (vr);
2478 /* Set MIN to the minimum of VAL[i] and MAX to the maximum
2482 for (i = 1; i < 4; i++)
2484 if (!is_gimple_min_invariant (min)
2485 || (TREE_OVERFLOW (min) && !is_overflow_infinity (min))
2486 || !is_gimple_min_invariant (max)
2487 || (TREE_OVERFLOW (max) && !is_overflow_infinity (max)))
2492 if (!is_gimple_min_invariant (val[i])
2493 || (TREE_OVERFLOW (val[i])
2494 && !is_overflow_infinity (val[i])))
2496 /* If we found an overflowed value, set MIN and MAX
2497 to it so that we set the resulting range to
2503 if (compare_values (val[i], min) == -1)
2506 if (compare_values (val[i], max) == 1)
2512 else if (code == TRUNC_MOD_EXPR
2513 || code == FLOOR_MOD_EXPR
2514 || code == CEIL_MOD_EXPR
2515 || code == ROUND_MOD_EXPR)
2518 if (vr0.type == VR_ANTI_RANGE
2519 || vr1.type != VR_RANGE
2520 || symbolic_range_p (&vr1)
2521 || range_includes_zero_p (&vr1))
2523 set_value_range_to_varying (vr);
2527 max = int_const_binop (MINUS_EXPR, vr1.max, integer_one_node, 0);
2528 if (vrp_expr_computes_nonnegative (op0, &sop)
2529 && vrp_expr_computes_nonnegative (op1, &sop) && !sop)
2530 min = build_int_cst (TREE_TYPE (vr1.max), 0);
2532 min = fold_unary (NEGATE_EXPR, TREE_TYPE (max), max);
2534 else if (code == MINUS_EXPR)
2536 /* If we have a MINUS_EXPR with two VR_ANTI_RANGEs, drop to
2537 VR_VARYING. It would take more effort to compute a precise
2538 range for such a case. For example, if we have op0 == 1 and
2539 op1 == 1 with their ranges both being ~[0,0], we would have
2540 op0 - op1 == 0, so we cannot claim that the difference is in
2541 ~[0,0]. Note that we are guaranteed to have
2542 vr0.type == vr1.type at this point. */
2543 if (vr0.type == VR_ANTI_RANGE)
2545 set_value_range_to_varying (vr);
2549 /* For MINUS_EXPR, apply the operation to the opposite ends of
2551 min = vrp_int_const_binop (code, vr0.min, vr1.max);
2552 max = vrp_int_const_binop (code, vr0.max, vr1.min);
2554 else if (code == BIT_AND_EXPR)
2556 bool vr0_int_cst_singleton_p, vr1_int_cst_singleton_p;
2558 vr0_int_cst_singleton_p = range_int_cst_singleton_p (&vr0);
2559 vr1_int_cst_singleton_p = range_int_cst_singleton_p (&vr1);
2561 if (vr0_int_cst_singleton_p && vr1_int_cst_singleton_p)
2562 min = max = int_const_binop (code, vr0.max, vr1.max, 0);
2563 else if (vr0_int_cst_singleton_p
2564 && tree_int_cst_sgn (vr0.max) >= 0)
2566 min = build_int_cst (expr_type, 0);
2569 else if (vr1_int_cst_singleton_p
2570 && tree_int_cst_sgn (vr1.max) >= 0)
2573 min = build_int_cst (expr_type, 0);
2578 set_value_range_to_varying (vr);
2582 else if (code == BIT_IOR_EXPR)
2584 if (range_int_cst_p (&vr0)
2585 && range_int_cst_p (&vr1)
2586 && tree_int_cst_sgn (vr0.min) >= 0
2587 && tree_int_cst_sgn (vr1.min) >= 0)
2589 double_int vr0_max = tree_to_double_int (vr0.max);
2590 double_int vr1_max = tree_to_double_int (vr1.max);
2593 /* Set all bits to the right of the most significant one to 1.
2594 For example, [0, 4] | [4, 4] = [4, 7]. */
2595 ior_max.low = vr0_max.low | vr1_max.low;
2596 ior_max.high = vr0_max.high | vr1_max.high;
2597 if (ior_max.high != 0)
2599 ior_max.low = ~(unsigned HOST_WIDE_INT)0u;
2600 ior_max.high |= ((HOST_WIDE_INT) 1
2601 << floor_log2 (ior_max.high)) - 1;
2603 else if (ior_max.low != 0)
2604 ior_max.low |= ((unsigned HOST_WIDE_INT) 1u
2605 << floor_log2 (ior_max.low)) - 1;
2607 /* Both of these endpoints are conservative. */
2608 min = vrp_int_const_binop (MAX_EXPR, vr0.min, vr1.min);
2609 max = double_int_to_tree (expr_type, ior_max);
2613 set_value_range_to_varying (vr);
2620 /* If either MIN or MAX overflowed, then set the resulting range to
2621 VARYING. But we do accept an overflow infinity
2623 if (min == NULL_TREE
2624 || !is_gimple_min_invariant (min)
2625 || (TREE_OVERFLOW (min) && !is_overflow_infinity (min))
2627 || !is_gimple_min_invariant (max)
2628 || (TREE_OVERFLOW (max) && !is_overflow_infinity (max)))
2630 set_value_range_to_varying (vr);
2636 2) [-INF, +-INF(OVF)]
2637 3) [+-INF(OVF), +INF]
2638 4) [+-INF(OVF), +-INF(OVF)]
2639 We learn nothing when we have INF and INF(OVF) on both sides.
2640 Note that we do accept [-INF, -INF] and [+INF, +INF] without
2642 if ((vrp_val_is_min (min) || is_overflow_infinity (min))
2643 && (vrp_val_is_max (max) || is_overflow_infinity (max)))
2645 set_value_range_to_varying (vr);
2649 cmp = compare_values (min, max);
2650 if (cmp == -2 || cmp == 1)
2652 /* If the new range has its limits swapped around (MIN > MAX),
2653 then the operation caused one of them to wrap around, mark
2654 the new range VARYING. */
2655 set_value_range_to_varying (vr);
2658 set_value_range (vr, type, min, max, NULL);
2662 /* Extract range information from a unary expression EXPR based on
2663 the range of its operand and the expression code. */
2666 extract_range_from_unary_expr (value_range_t *vr, enum tree_code code,
2667 tree type, tree op0)
2671 value_range_t vr0 = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
2673 /* Refuse to operate on certain unary expressions for which we
2674 cannot easily determine a resulting range. */
2675 if (code == FIX_TRUNC_EXPR
2676 || code == FLOAT_EXPR
2677 || code == BIT_NOT_EXPR
2678 || code == CONJ_EXPR)
2680 /* We can still do constant propagation here. */
2681 if ((op0 = op_with_constant_singleton_value_range (op0)) != NULL_TREE)
2683 tree tem = fold_unary (code, type, op0);
2685 && is_gimple_min_invariant (tem)
2686 && !is_overflow_infinity (tem))
2688 set_value_range (vr, VR_RANGE, tem, tem, NULL);
2692 set_value_range_to_varying (vr);
2696 /* Get value ranges for the operand. For constant operands, create
2697 a new value range with the operand to simplify processing. */
2698 if (TREE_CODE (op0) == SSA_NAME)
2699 vr0 = *(get_value_range (op0));
2700 else if (is_gimple_min_invariant (op0))
2701 set_value_range_to_value (&vr0, op0, NULL);
2703 set_value_range_to_varying (&vr0);
2705 /* If VR0 is UNDEFINED, so is the result. */
2706 if (vr0.type == VR_UNDEFINED)
2708 set_value_range_to_undefined (vr);
2712 /* Refuse to operate on symbolic ranges, or if neither operand is
2713 a pointer or integral type. */
2714 if ((!INTEGRAL_TYPE_P (TREE_TYPE (op0))
2715 && !POINTER_TYPE_P (TREE_TYPE (op0)))
2716 || (vr0.type != VR_VARYING
2717 && symbolic_range_p (&vr0)))
2719 set_value_range_to_varying (vr);
2723 /* If the expression involves pointers, we are only interested in
2724 determining if it evaluates to NULL [0, 0] or non-NULL (~[0, 0]). */
2725 if (POINTER_TYPE_P (type) || POINTER_TYPE_P (TREE_TYPE (op0)))
2730 if (range_is_nonnull (&vr0)
2731 || (tree_unary_nonzero_warnv_p (code, type, op0, &sop)
2733 set_value_range_to_nonnull (vr, type);
2734 else if (range_is_null (&vr0))
2735 set_value_range_to_null (vr, type);
2737 set_value_range_to_varying (vr);
2742 /* Handle unary expressions on integer ranges. */
2743 if (CONVERT_EXPR_CODE_P (code)
2744 && INTEGRAL_TYPE_P (type)
2745 && INTEGRAL_TYPE_P (TREE_TYPE (op0)))
2747 tree inner_type = TREE_TYPE (op0);
2748 tree outer_type = type;
2750 /* If VR0 is varying and we increase the type precision, assume
2751 a full range for the following transformation. */
2752 if (vr0.type == VR_VARYING
2753 && TYPE_PRECISION (inner_type) < TYPE_PRECISION (outer_type))
2755 vr0.type = VR_RANGE;
2756 vr0.min = TYPE_MIN_VALUE (inner_type);
2757 vr0.max = TYPE_MAX_VALUE (inner_type);
2760 /* If VR0 is a constant range or anti-range and the conversion is
2761 not truncating we can convert the min and max values and
2762 canonicalize the resulting range. Otherwise we can do the
2763 conversion if the size of the range is less than what the
2764 precision of the target type can represent and the range is
2765 not an anti-range. */
2766 if ((vr0.type == VR_RANGE
2767 || vr0.type == VR_ANTI_RANGE)
2768 && TREE_CODE (vr0.min) == INTEGER_CST
2769 && TREE_CODE (vr0.max) == INTEGER_CST
2770 && (!is_overflow_infinity (vr0.min)
2771 || (vr0.type == VR_RANGE
2772 && TYPE_PRECISION (outer_type) > TYPE_PRECISION (inner_type)
2773 && needs_overflow_infinity (outer_type)
2774 && supports_overflow_infinity (outer_type)))
2775 && (!is_overflow_infinity (vr0.max)
2776 || (vr0.type == VR_RANGE
2777 && TYPE_PRECISION (outer_type) > TYPE_PRECISION (inner_type)
2778 && needs_overflow_infinity (outer_type)
2779 && supports_overflow_infinity (outer_type)))
2780 && (TYPE_PRECISION (outer_type) >= TYPE_PRECISION (inner_type)
2781 || (vr0.type == VR_RANGE
2782 && integer_zerop (int_const_binop (RSHIFT_EXPR,
2783 int_const_binop (MINUS_EXPR, vr0.max, vr0.min, 0),
2784 size_int (TYPE_PRECISION (outer_type)), 0)))))
2786 tree new_min, new_max;
2787 new_min = force_fit_type_double (outer_type,
2788 TREE_INT_CST_LOW (vr0.min),
2789 TREE_INT_CST_HIGH (vr0.min), 0, 0);
2790 new_max = force_fit_type_double (outer_type,
2791 TREE_INT_CST_LOW (vr0.max),
2792 TREE_INT_CST_HIGH (vr0.max), 0, 0);
2793 if (is_overflow_infinity (vr0.min))
2794 new_min = negative_overflow_infinity (outer_type);
2795 if (is_overflow_infinity (vr0.max))
2796 new_max = positive_overflow_infinity (outer_type);
2797 set_and_canonicalize_value_range (vr, vr0.type,
2798 new_min, new_max, NULL);
2802 set_value_range_to_varying (vr);
2806 /* Conversion of a VR_VARYING value to a wider type can result
2807 in a usable range. So wait until after we've handled conversions
2808 before dropping the result to VR_VARYING if we had a source
2809 operand that is VR_VARYING. */
2810 if (vr0.type == VR_VARYING)
2812 set_value_range_to_varying (vr);
2816 /* Apply the operation to each end of the range and see what we end
2818 if (code == NEGATE_EXPR
2819 && !TYPE_UNSIGNED (type))
2821 /* NEGATE_EXPR flips the range around. We need to treat
2822 TYPE_MIN_VALUE specially. */
2823 if (is_positive_overflow_infinity (vr0.max))
2824 min = negative_overflow_infinity (type);
2825 else if (is_negative_overflow_infinity (vr0.max))
2826 min = positive_overflow_infinity (type);
2827 else if (!vrp_val_is_min (vr0.max))
2828 min = fold_unary_to_constant (code, type, vr0.max);
2829 else if (needs_overflow_infinity (type))
2831 if (supports_overflow_infinity (type)
2832 && !is_overflow_infinity (vr0.min)
2833 && !vrp_val_is_min (vr0.min))
2834 min = positive_overflow_infinity (type);
2837 set_value_range_to_varying (vr);
2842 min = TYPE_MIN_VALUE (type);
2844 if (is_positive_overflow_infinity (vr0.min))
2845 max = negative_overflow_infinity (type);
2846 else if (is_negative_overflow_infinity (vr0.min))
2847 max = positive_overflow_infinity (type);
2848 else if (!vrp_val_is_min (vr0.min))
2849 max = fold_unary_to_constant (code, type, vr0.min);
2850 else if (needs_overflow_infinity (type))
2852 if (supports_overflow_infinity (type))
2853 max = positive_overflow_infinity (type);
2856 set_value_range_to_varying (vr);
2861 max = TYPE_MIN_VALUE (type);
2863 else if (code == NEGATE_EXPR
2864 && TYPE_UNSIGNED (type))
2866 if (!range_includes_zero_p (&vr0))
2868 max = fold_unary_to_constant (code, type, vr0.min);
2869 min = fold_unary_to_constant (code, type, vr0.max);
2873 if (range_is_null (&vr0))
2874 set_value_range_to_null (vr, type);
2876 set_value_range_to_varying (vr);
2880 else if (code == ABS_EXPR
2881 && !TYPE_UNSIGNED (type))
2883 /* -TYPE_MIN_VALUE = TYPE_MIN_VALUE with flag_wrapv so we can't get a
2885 if (!TYPE_OVERFLOW_UNDEFINED (type)
2886 && ((vr0.type == VR_RANGE
2887 && vrp_val_is_min (vr0.min))
2888 || (vr0.type == VR_ANTI_RANGE
2889 && !vrp_val_is_min (vr0.min)
2890 && !range_includes_zero_p (&vr0))))
2892 set_value_range_to_varying (vr);
2896 /* ABS_EXPR may flip the range around, if the original range
2897 included negative values. */
2898 if (is_overflow_infinity (vr0.min))
2899 min = positive_overflow_infinity (type);
2900 else if (!vrp_val_is_min (vr0.min))
2901 min = fold_unary_to_constant (code, type, vr0.min);
2902 else if (!needs_overflow_infinity (type))
2903 min = TYPE_MAX_VALUE (type);
2904 else if (supports_overflow_infinity (type))
2905 min = positive_overflow_infinity (type);
2908 set_value_range_to_varying (vr);
2912 if (is_overflow_infinity (vr0.max))
2913 max = positive_overflow_infinity (type);
2914 else if (!vrp_val_is_min (vr0.max))
2915 max = fold_unary_to_constant (code, type, vr0.max);
2916 else if (!needs_overflow_infinity (type))
2917 max = TYPE_MAX_VALUE (type);
2918 else if (supports_overflow_infinity (type)
2919 /* We shouldn't generate [+INF, +INF] as set_value_range
2920 doesn't like this and ICEs. */
2921 && !is_positive_overflow_infinity (min))
2922 max = positive_overflow_infinity (type);
2925 set_value_range_to_varying (vr);
2929 cmp = compare_values (min, max);
2931 /* If a VR_ANTI_RANGEs contains zero, then we have
2932 ~[-INF, min(MIN, MAX)]. */
2933 if (vr0.type == VR_ANTI_RANGE)
2935 if (range_includes_zero_p (&vr0))
2937 /* Take the lower of the two values. */
2941 /* Create ~[-INF, min (abs(MIN), abs(MAX))]
2942 or ~[-INF + 1, min (abs(MIN), abs(MAX))] when
2943 flag_wrapv is set and the original anti-range doesn't include
2944 TYPE_MIN_VALUE, remember -TYPE_MIN_VALUE = TYPE_MIN_VALUE. */
2945 if (TYPE_OVERFLOW_WRAPS (type))
2947 tree type_min_value = TYPE_MIN_VALUE (type);
2949 min = (vr0.min != type_min_value
2950 ? int_const_binop (PLUS_EXPR, type_min_value,
2951 integer_one_node, 0)
2956 if (overflow_infinity_range_p (&vr0))
2957 min = negative_overflow_infinity (type);
2959 min = TYPE_MIN_VALUE (type);
2964 /* All else has failed, so create the range [0, INF], even for
2965 flag_wrapv since TYPE_MIN_VALUE is in the original
2967 vr0.type = VR_RANGE;
2968 min = build_int_cst (type, 0);
2969 if (needs_overflow_infinity (type))
2971 if (supports_overflow_infinity (type))
2972 max = positive_overflow_infinity (type);
2975 set_value_range_to_varying (vr);
2980 max = TYPE_MAX_VALUE (type);
2984 /* If the range contains zero then we know that the minimum value in the
2985 range will be zero. */
2986 else if (range_includes_zero_p (&vr0))
2990 min = build_int_cst (type, 0);
2994 /* If the range was reversed, swap MIN and MAX. */
3005 /* Otherwise, operate on each end of the range. */
3006 min = fold_unary_to_constant (code, type, vr0.min);
3007 max = fold_unary_to_constant (code, type, vr0.max);
3009 if (needs_overflow_infinity (type))
3011 gcc_assert (code != NEGATE_EXPR && code != ABS_EXPR);
3013 /* If both sides have overflowed, we don't know
3015 if ((is_overflow_infinity (vr0.min)
3016 || TREE_OVERFLOW (min))
3017 && (is_overflow_infinity (vr0.max)
3018 || TREE_OVERFLOW (max)))
3020 set_value_range_to_varying (vr);
3024 if (is_overflow_infinity (vr0.min))
3026 else if (TREE_OVERFLOW (min))
3028 if (supports_overflow_infinity (type))
3029 min = (tree_int_cst_sgn (min) >= 0
3030 ? positive_overflow_infinity (TREE_TYPE (min))
3031 : negative_overflow_infinity (TREE_TYPE (min)));
3034 set_value_range_to_varying (vr);
3039 if (is_overflow_infinity (vr0.max))
3041 else if (TREE_OVERFLOW (max))
3043 if (supports_overflow_infinity (type))
3044 max = (tree_int_cst_sgn (max) >= 0
3045 ? positive_overflow_infinity (TREE_TYPE (max))
3046 : negative_overflow_infinity (TREE_TYPE (max)));
3049 set_value_range_to_varying (vr);
3056 cmp = compare_values (min, max);
3057 if (cmp == -2 || cmp == 1)
3059 /* If the new range has its limits swapped around (MIN > MAX),
3060 then the operation caused one of them to wrap around, mark
3061 the new range VARYING. */
3062 set_value_range_to_varying (vr);
3065 set_value_range (vr, vr0.type, min, max, NULL);
3069 /* Extract range information from a conditional expression EXPR based on
3070 the ranges of each of its operands and the expression code. */
3073 extract_range_from_cond_expr (value_range_t *vr, tree expr)
3076 value_range_t vr0 = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
3077 value_range_t vr1 = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
3079 /* Get value ranges for each operand. For constant operands, create
3080 a new value range with the operand to simplify processing. */
3081 op0 = COND_EXPR_THEN (expr);
3082 if (TREE_CODE (op0) == SSA_NAME)
3083 vr0 = *(get_value_range (op0));
3084 else if (is_gimple_min_invariant (op0))
3085 set_value_range_to_value (&vr0, op0, NULL);
3087 set_value_range_to_varying (&vr0);
3089 op1 = COND_EXPR_ELSE (expr);
3090 if (TREE_CODE (op1) == SSA_NAME)
3091 vr1 = *(get_value_range (op1));
3092 else if (is_gimple_min_invariant (op1))
3093 set_value_range_to_value (&vr1, op1, NULL);
3095 set_value_range_to_varying (&vr1);
3097 /* The resulting value range is the union of the operand ranges */
3098 vrp_meet (&vr0, &vr1);
3099 copy_value_range (vr, &vr0);
3103 /* Extract range information from a comparison expression EXPR based
3104 on the range of its operand and the expression code. */
3107 extract_range_from_comparison (value_range_t *vr, enum tree_code code,
3108 tree type, tree op0, tree op1)
3113 val = vrp_evaluate_conditional_warnv_with_ops (code, op0, op1, false, &sop,
3116 /* A disadvantage of using a special infinity as an overflow
3117 representation is that we lose the ability to record overflow
3118 when we don't have an infinity. So we have to ignore a result
3119 which relies on overflow. */
3121 if (val && !is_overflow_infinity (val) && !sop)
3123 /* Since this expression was found on the RHS of an assignment,
3124 its type may be different from _Bool. Convert VAL to EXPR's
3126 val = fold_convert (type, val);
3127 if (is_gimple_min_invariant (val))
3128 set_value_range_to_value (vr, val, vr->equiv);
3130 set_value_range (vr, VR_RANGE, val, val, vr->equiv);
3133 /* The result of a comparison is always true or false. */
3134 set_value_range_to_truthvalue (vr, type);
3137 /* Try to derive a nonnegative or nonzero range out of STMT relying
3138 primarily on generic routines in fold in conjunction with range data.
3139 Store the result in *VR */
3142 extract_range_basic (value_range_t *vr, gimple stmt)
3145 tree type = gimple_expr_type (stmt);
3147 if (INTEGRAL_TYPE_P (type)
3148 && gimple_stmt_nonnegative_warnv_p (stmt, &sop))
3149 set_value_range_to_nonnegative (vr, type,
3150 sop || stmt_overflow_infinity (stmt));
3151 else if (vrp_stmt_computes_nonzero (stmt, &sop)
3153 set_value_range_to_nonnull (vr, type);
3155 set_value_range_to_varying (vr);
3159 /* Try to compute a useful range out of assignment STMT and store it
3163 extract_range_from_assignment (value_range_t *vr, gimple stmt)
3165 enum tree_code code = gimple_assign_rhs_code (stmt);
3167 if (code == ASSERT_EXPR)
3168 extract_range_from_assert (vr, gimple_assign_rhs1 (stmt));
3169 else if (code == SSA_NAME)
3170 extract_range_from_ssa_name (vr, gimple_assign_rhs1 (stmt));
3171 else if (TREE_CODE_CLASS (code) == tcc_binary
3172 || code == TRUTH_AND_EXPR
3173 || code == TRUTH_OR_EXPR
3174 || code == TRUTH_XOR_EXPR)
3175 extract_range_from_binary_expr (vr, gimple_assign_rhs_code (stmt),
3176 gimple_expr_type (stmt),
3177 gimple_assign_rhs1 (stmt),
3178 gimple_assign_rhs2 (stmt));
3179 else if (TREE_CODE_CLASS (code) == tcc_unary)
3180 extract_range_from_unary_expr (vr, gimple_assign_rhs_code (stmt),
3181 gimple_expr_type (stmt),
3182 gimple_assign_rhs1 (stmt));
3183 else if (code == COND_EXPR)
3184 extract_range_from_cond_expr (vr, gimple_assign_rhs1 (stmt));
3185 else if (TREE_CODE_CLASS (code) == tcc_comparison)
3186 extract_range_from_comparison (vr, gimple_assign_rhs_code (stmt),
3187 gimple_expr_type (stmt),
3188 gimple_assign_rhs1 (stmt),
3189 gimple_assign_rhs2 (stmt));
3190 else if (get_gimple_rhs_class (code) == GIMPLE_SINGLE_RHS
3191 && is_gimple_min_invariant (gimple_assign_rhs1 (stmt)))
3192 set_value_range_to_value (vr, gimple_assign_rhs1 (stmt), NULL);
3194 set_value_range_to_varying (vr);
3196 if (vr->type == VR_VARYING)
3197 extract_range_basic (vr, stmt);
3200 /* Given a range VR, a LOOP and a variable VAR, determine whether it
3201 would be profitable to adjust VR using scalar evolution information
3202 for VAR. If so, update VR with the new limits. */
3205 adjust_range_with_scev (value_range_t *vr, struct loop *loop,
3206 gimple stmt, tree var)
3208 tree init, step, chrec, tmin, tmax, min, max, type, tem;
3209 enum ev_direction dir;
3211 /* TODO. Don't adjust anti-ranges. An anti-range may provide
3212 better opportunities than a regular range, but I'm not sure. */
3213 if (vr->type == VR_ANTI_RANGE)
3216 chrec = instantiate_parameters (loop, analyze_scalar_evolution (loop, var));
3218 /* Like in PR19590, scev can return a constant function. */
3219 if (is_gimple_min_invariant (chrec))
3221 set_value_range_to_value (vr, chrec, vr->equiv);
3225 if (TREE_CODE (chrec) != POLYNOMIAL_CHREC)
3228 init = initial_condition_in_loop_num (chrec, loop->num);
3229 tem = op_with_constant_singleton_value_range (init);
3232 step = evolution_part_in_loop_num (chrec, loop->num);
3233 tem = op_with_constant_singleton_value_range (step);
3237 /* If STEP is symbolic, we can't know whether INIT will be the
3238 minimum or maximum value in the range. Also, unless INIT is
3239 a simple expression, compare_values and possibly other functions
3240 in tree-vrp won't be able to handle it. */
3241 if (step == NULL_TREE
3242 || !is_gimple_min_invariant (step)
3243 || !valid_value_p (init))
3246 dir = scev_direction (chrec);
3247 if (/* Do not adjust ranges if we do not know whether the iv increases
3248 or decreases, ... */
3249 dir == EV_DIR_UNKNOWN
3250 /* ... or if it may wrap. */
3251 || scev_probably_wraps_p (init, step, stmt, get_chrec_loop (chrec),
3255 /* We use TYPE_MIN_VALUE and TYPE_MAX_VALUE here instead of
3256 negative_overflow_infinity and positive_overflow_infinity,
3257 because we have concluded that the loop probably does not
3260 type = TREE_TYPE (var);
3261 if (POINTER_TYPE_P (type) || !TYPE_MIN_VALUE (type))
3262 tmin = lower_bound_in_type (type, type);
3264 tmin = TYPE_MIN_VALUE (type);
3265 if (POINTER_TYPE_P (type) || !TYPE_MAX_VALUE (type))
3266 tmax = upper_bound_in_type (type, type);
3268 tmax = TYPE_MAX_VALUE (type);
3270 if (vr->type == VR_VARYING || vr->type == VR_UNDEFINED)
3275 /* For VARYING or UNDEFINED ranges, just about anything we get
3276 from scalar evolutions should be better. */
3278 if (dir == EV_DIR_DECREASES)
3283 /* If we would create an invalid range, then just assume we
3284 know absolutely nothing. This may be over-conservative,
3285 but it's clearly safe, and should happen only in unreachable
3286 parts of code, or for invalid programs. */
3287 if (compare_values (min, max) == 1)
3290 set_value_range (vr, VR_RANGE, min, max, vr->equiv);
3292 else if (vr->type == VR_RANGE)
3297 if (dir == EV_DIR_DECREASES)
3299 /* INIT is the maximum value. If INIT is lower than VR->MAX
3300 but no smaller than VR->MIN, set VR->MAX to INIT. */
3301 if (compare_values (init, max) == -1)
3305 /* If we just created an invalid range with the minimum
3306 greater than the maximum, we fail conservatively.
3307 This should happen only in unreachable
3308 parts of code, or for invalid programs. */
3309 if (compare_values (min, max) == 1)
3313 /* According to the loop information, the variable does not
3314 overflow. If we think it does, probably because of an
3315 overflow due to arithmetic on a different INF value,
3317 if (is_negative_overflow_infinity (min))
3322 /* If INIT is bigger than VR->MIN, set VR->MIN to INIT. */
3323 if (compare_values (init, min) == 1)
3327 /* Again, avoid creating invalid range by failing. */
3328 if (compare_values (min, max) == 1)
3332 if (is_positive_overflow_infinity (max))
3336 set_value_range (vr, VR_RANGE, min, max, vr->equiv);
3340 /* Return true if VAR may overflow at STMT. This checks any available
3341 loop information to see if we can determine that VAR does not
3345 vrp_var_may_overflow (tree var, gimple stmt)
3348 tree chrec, init, step;
3350 if (current_loops == NULL)
3353 l = loop_containing_stmt (stmt);
3358 chrec = instantiate_parameters (l, analyze_scalar_evolution (l, var));
3359 if (TREE_CODE (chrec) != POLYNOMIAL_CHREC)
3362 init = initial_condition_in_loop_num (chrec, l->num);
3363 step = evolution_part_in_loop_num (chrec, l->num);
3365 if (step == NULL_TREE
3366 || !is_gimple_min_invariant (step)
3367 || !valid_value_p (init))
3370 /* If we get here, we know something useful about VAR based on the
3371 loop information. If it wraps, it may overflow. */
3373 if (scev_probably_wraps_p (init, step, stmt, get_chrec_loop (chrec),
3377 if (dump_file && (dump_flags & TDF_DETAILS) != 0)
3379 print_generic_expr (dump_file, var, 0);
3380 fprintf (dump_file, ": loop information indicates does not overflow\n");
3387 /* Given two numeric value ranges VR0, VR1 and a comparison code COMP:
3389 - Return BOOLEAN_TRUE_NODE if VR0 COMP VR1 always returns true for
3390 all the values in the ranges.
3392 - Return BOOLEAN_FALSE_NODE if the comparison always returns false.
3394 - Return NULL_TREE if it is not always possible to determine the
3395 value of the comparison.
3397 Also set *STRICT_OVERFLOW_P to indicate whether a range with an
3398 overflow infinity was used in the test. */
3402 compare_ranges (enum tree_code comp, value_range_t *vr0, value_range_t *vr1,
3403 bool *strict_overflow_p)
3405 /* VARYING or UNDEFINED ranges cannot be compared. */
3406 if (vr0->type == VR_VARYING
3407 || vr0->type == VR_UNDEFINED
3408 || vr1->type == VR_VARYING
3409 || vr1->type == VR_UNDEFINED)
3412 /* Anti-ranges need to be handled separately. */
3413 if (vr0->type == VR_ANTI_RANGE || vr1->type == VR_ANTI_RANGE)
3415 /* If both are anti-ranges, then we cannot compute any
3417 if (vr0->type == VR_ANTI_RANGE && vr1->type == VR_ANTI_RANGE)
3420 /* These comparisons are never statically computable. */
3427 /* Equality can be computed only between a range and an
3428 anti-range. ~[VAL1, VAL2] == [VAL1, VAL2] is always false. */
3429 if (vr0->type == VR_RANGE)
3431 /* To simplify processing, make VR0 the anti-range. */
3432 value_range_t *tmp = vr0;
3437 gcc_assert (comp == NE_EXPR || comp == EQ_EXPR);
3439 if (compare_values_warnv (vr0->min, vr1->min, strict_overflow_p) == 0
3440 && compare_values_warnv (vr0->max, vr1->max, strict_overflow_p) == 0)
3441 return (comp == NE_EXPR) ? boolean_true_node : boolean_false_node;
3446 if (!usable_range_p (vr0, strict_overflow_p)
3447 || !usable_range_p (vr1, strict_overflow_p))
3450 /* Simplify processing. If COMP is GT_EXPR or GE_EXPR, switch the
3451 operands around and change the comparison code. */
3452 if (comp == GT_EXPR || comp == GE_EXPR)
3455 comp = (comp == GT_EXPR) ? LT_EXPR : LE_EXPR;
3461 if (comp == EQ_EXPR)
3463 /* Equality may only be computed if both ranges represent
3464 exactly one value. */
3465 if (compare_values_warnv (vr0->min, vr0->max, strict_overflow_p) == 0
3466 && compare_values_warnv (vr1->min, vr1->max, strict_overflow_p) == 0)
3468 int cmp_min = compare_values_warnv (vr0->min, vr1->min,
3470 int cmp_max = compare_values_warnv (vr0->max, vr1->max,
3472 if (cmp_min == 0 && cmp_max == 0)
3473 return boolean_true_node;
3474 else if (cmp_min != -2 && cmp_max != -2)
3475 return boolean_false_node;
3477 /* If [V0_MIN, V1_MAX] < [V1_MIN, V1_MAX] then V0 != V1. */
3478 else if (compare_values_warnv (vr0->min, vr1->max,
3479 strict_overflow_p) == 1
3480 || compare_values_warnv (vr1->min, vr0->max,
3481 strict_overflow_p) == 1)
3482 return boolean_false_node;
3486 else if (comp == NE_EXPR)
3490 /* If VR0 is completely to the left or completely to the right
3491 of VR1, they are always different. Notice that we need to
3492 make sure that both comparisons yield similar results to
3493 avoid comparing values that cannot be compared at
3495 cmp1 = compare_values_warnv (vr0->max, vr1->min, strict_overflow_p);
3496 cmp2 = compare_values_warnv (vr0->min, vr1->max, strict_overflow_p);
3497 if ((cmp1 == -1 && cmp2 == -1) || (cmp1 == 1 && cmp2 == 1))
3498 return boolean_true_node;
3500 /* If VR0 and VR1 represent a single value and are identical,
3502 else if (compare_values_warnv (vr0->min, vr0->max,
3503 strict_overflow_p) == 0
3504 && compare_values_warnv (vr1->min, vr1->max,
3505 strict_overflow_p) == 0
3506 && compare_values_warnv (vr0->min, vr1->min,
3507 strict_overflow_p) == 0
3508 && compare_values_warnv (vr0->max, vr1->max,
3509 strict_overflow_p) == 0)
3510 return boolean_false_node;
3512 /* Otherwise, they may or may not be different. */
3516 else if (comp == LT_EXPR || comp == LE_EXPR)
3520 /* If VR0 is to the left of VR1, return true. */
3521 tst = compare_values_warnv (vr0->max, vr1->min, strict_overflow_p);
3522 if ((comp == LT_EXPR && tst == -1)
3523 || (comp == LE_EXPR && (tst == -1 || tst == 0)))
3525 if (overflow_infinity_range_p (vr0)
3526 || overflow_infinity_range_p (vr1))
3527 *strict_overflow_p = true;
3528 return boolean_true_node;
3531 /* If VR0 is to the right of VR1, return false. */
3532 tst = compare_values_warnv (vr0->min, vr1->max, strict_overflow_p);
3533 if ((comp == LT_EXPR && (tst == 0 || tst == 1))
3534 || (comp == LE_EXPR && tst == 1))
3536 if (overflow_infinity_range_p (vr0)
3537 || overflow_infinity_range_p (vr1))
3538 *strict_overflow_p = true;
3539 return boolean_false_node;
3542 /* Otherwise, we don't know. */
3550 /* Given a value range VR, a value VAL and a comparison code COMP, return
3551 BOOLEAN_TRUE_NODE if VR COMP VAL always returns true for all the
3552 values in VR. Return BOOLEAN_FALSE_NODE if the comparison
3553 always returns false. Return NULL_TREE if it is not always
3554 possible to determine the value of the comparison. Also set
3555 *STRICT_OVERFLOW_P to indicate whether a range with an overflow
3556 infinity was used in the test. */
3559 compare_range_with_value (enum tree_code comp, value_range_t *vr, tree val,
3560 bool *strict_overflow_p)
3562 if (vr->type == VR_VARYING || vr->type == VR_UNDEFINED)
3565 /* Anti-ranges need to be handled separately. */
3566 if (vr->type == VR_ANTI_RANGE)
3568 /* For anti-ranges, the only predicates that we can compute at
3569 compile time are equality and inequality. */
3576 /* ~[VAL_1, VAL_2] OP VAL is known if VAL_1 <= VAL <= VAL_2. */
3577 if (value_inside_range (val, vr) == 1)
3578 return (comp == NE_EXPR) ? boolean_true_node : boolean_false_node;
3583 if (!usable_range_p (vr, strict_overflow_p))
3586 if (comp == EQ_EXPR)
3588 /* EQ_EXPR may only be computed if VR represents exactly
3590 if (compare_values_warnv (vr->min, vr->max, strict_overflow_p) == 0)
3592 int cmp = compare_values_warnv (vr->min, val, strict_overflow_p);
3594 return boolean_true_node;
3595 else if (cmp == -1 || cmp == 1 || cmp == 2)
3596 return boolean_false_node;
3598 else if (compare_values_warnv (val, vr->min, strict_overflow_p) == -1
3599 || compare_values_warnv (vr->max, val, strict_overflow_p) == -1)
3600 return boolean_false_node;
3604 else if (comp == NE_EXPR)
3606 /* If VAL is not inside VR, then they are always different. */
3607 if (compare_values_warnv (vr->max, val, strict_overflow_p) == -1
3608 || compare_values_warnv (vr->min, val, strict_overflow_p) == 1)
3609 return boolean_true_node;
3611 /* If VR represents exactly one value equal to VAL, then return
3613 if (compare_values_warnv (vr->min, vr->max, strict_overflow_p) == 0
3614 && compare_values_warnv (vr->min, val, strict_overflow_p) == 0)
3615 return boolean_false_node;
3617 /* Otherwise, they may or may not be different. */
3620 else if (comp == LT_EXPR || comp == LE_EXPR)
3624 /* If VR is to the left of VAL, return true. */
3625 tst = compare_values_warnv (vr->max, val, strict_overflow_p);
3626 if ((comp == LT_EXPR && tst == -1)
3627 || (comp == LE_EXPR && (tst == -1 || tst == 0)))
3629 if (overflow_infinity_range_p (vr))
3630 *strict_overflow_p = true;
3631 return boolean_true_node;
3634 /* If VR is to the right of VAL, return false. */
3635 tst = compare_values_warnv (vr->min, val, strict_overflow_p);
3636 if ((comp == LT_EXPR && (tst == 0 || tst == 1))
3637 || (comp == LE_EXPR && tst == 1))
3639 if (overflow_infinity_range_p (vr))
3640 *strict_overflow_p = true;
3641 return boolean_false_node;
3644 /* Otherwise, we don't know. */
3647 else if (comp == GT_EXPR || comp == GE_EXPR)
3651 /* If VR is to the right of VAL, return true. */
3652 tst = compare_values_warnv (vr->min, val, strict_overflow_p);
3653 if ((comp == GT_EXPR && tst == 1)
3654 || (comp == GE_EXPR && (tst == 0 || tst == 1)))
3656 if (overflow_infinity_range_p (vr))
3657 *strict_overflow_p = true;
3658 return boolean_true_node;
3661 /* If VR is to the left of VAL, return false. */
3662 tst = compare_values_warnv (vr->max, val, strict_overflow_p);
3663 if ((comp == GT_EXPR && (tst == -1 || tst == 0))
3664 || (comp == GE_EXPR && tst == -1))
3666 if (overflow_infinity_range_p (vr))
3667 *strict_overflow_p = true;
3668 return boolean_false_node;
3671 /* Otherwise, we don't know. */
3679 /* Debugging dumps. */
3681 void dump_value_range (FILE *, value_range_t *);
3682 void debug_value_range (value_range_t *);
3683 void dump_all_value_ranges (FILE *);
3684 void debug_all_value_ranges (void);
3685 void dump_vr_equiv (FILE *, bitmap);
3686 void debug_vr_equiv (bitmap);
3689 /* Dump value range VR to FILE. */
3692 dump_value_range (FILE *file, value_range_t *vr)
3695 fprintf (file, "[]");
3696 else if (vr->type == VR_UNDEFINED)
3697 fprintf (file, "UNDEFINED");
3698 else if (vr->type == VR_RANGE || vr->type == VR_ANTI_RANGE)
3700 tree type = TREE_TYPE (vr->min);
3702 fprintf (file, "%s[", (vr->type == VR_ANTI_RANGE) ? "~" : "");
3704 if (is_negative_overflow_infinity (vr->min))
3705 fprintf (file, "-INF(OVF)");
3706 else if (INTEGRAL_TYPE_P (type)
3707 && !TYPE_UNSIGNED (type)
3708 && vrp_val_is_min (vr->min))
3709 fprintf (file, "-INF");
3711 print_generic_expr (file, vr->min, 0);
3713 fprintf (file, ", ");
3715 if (is_positive_overflow_infinity (vr->max))
3716 fprintf (file, "+INF(OVF)");
3717 else if (INTEGRAL_TYPE_P (type)
3718 && vrp_val_is_max (vr->max))
3719 fprintf (file, "+INF");
3721 print_generic_expr (file, vr->max, 0);
3723 fprintf (file, "]");
3730 fprintf (file, " EQUIVALENCES: { ");
3732 EXECUTE_IF_SET_IN_BITMAP (vr->equiv, 0, i, bi)
3734 print_generic_expr (file, ssa_name (i), 0);
3735 fprintf (file, " ");
3739 fprintf (file, "} (%u elements)", c);
3742 else if (vr->type == VR_VARYING)
3743 fprintf (file, "VARYING");
3745 fprintf (file, "INVALID RANGE");
3749 /* Dump value range VR to stderr. */
3752 debug_value_range (value_range_t *vr)
3754 dump_value_range (stderr, vr);
3755 fprintf (stderr, "\n");
3759 /* Dump value ranges of all SSA_NAMEs to FILE. */
3762 dump_all_value_ranges (FILE *file)
3766 for (i = 0; i < num_ssa_names; i++)
3770 print_generic_expr (file, ssa_name (i), 0);
3771 fprintf (file, ": ");
3772 dump_value_range (file, vr_value[i]);
3773 fprintf (file, "\n");
3777 fprintf (file, "\n");
3781 /* Dump all value ranges to stderr. */
3784 debug_all_value_ranges (void)
3786 dump_all_value_ranges (stderr);
3790 /* Given a COND_EXPR COND of the form 'V OP W', and an SSA name V,
3791 create a new SSA name N and return the assertion assignment
3792 'V = ASSERT_EXPR <V, V OP W>'. */
3795 build_assert_expr_for (tree cond, tree v)
3800 gcc_assert (TREE_CODE (v) == SSA_NAME);
3801 n = duplicate_ssa_name (v, NULL);
3803 if (COMPARISON_CLASS_P (cond))
3805 tree a = build2 (ASSERT_EXPR, TREE_TYPE (v), v, cond);
3806 assertion = gimple_build_assign (n, a);
3808 else if (TREE_CODE (cond) == TRUTH_NOT_EXPR)
3810 /* Given !V, build the assignment N = false. */
3811 tree op0 = TREE_OPERAND (cond, 0);
3812 gcc_assert (op0 == v);
3813 assertion = gimple_build_assign (n, boolean_false_node);
3815 else if (TREE_CODE (cond) == SSA_NAME)
3817 /* Given V, build the assignment N = true. */
3818 gcc_assert (v == cond);
3819 assertion = gimple_build_assign (n, boolean_true_node);
3824 SSA_NAME_DEF_STMT (n) = assertion;
3826 /* The new ASSERT_EXPR, creates a new SSA name that replaces the
3827 operand of the ASSERT_EXPR. Register the new name and the old one
3828 in the replacement table so that we can fix the SSA web after
3829 adding all the ASSERT_EXPRs. */
3830 register_new_name_mapping (n, v);
3836 /* Return false if EXPR is a predicate expression involving floating
3840 fp_predicate (gimple stmt)
3842 GIMPLE_CHECK (stmt, GIMPLE_COND);
3844 return FLOAT_TYPE_P (TREE_TYPE (gimple_cond_lhs (stmt)));
3848 /* If the range of values taken by OP can be inferred after STMT executes,
3849 return the comparison code (COMP_CODE_P) and value (VAL_P) that
3850 describes the inferred range. Return true if a range could be
3854 infer_value_range (gimple stmt, tree op, enum tree_code *comp_code_p, tree *val_p)
3857 *comp_code_p = ERROR_MARK;
3859 /* Do not attempt to infer anything in names that flow through
3861 if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (op))
3864 /* Similarly, don't infer anything from statements that may throw
3866 if (stmt_could_throw_p (stmt))
3869 /* If STMT is the last statement of a basic block with no
3870 successors, there is no point inferring anything about any of its
3871 operands. We would not be able to find a proper insertion point
3872 for the assertion, anyway. */
3873 if (stmt_ends_bb_p (stmt) && EDGE_COUNT (gimple_bb (stmt)->succs) == 0)
3876 /* We can only assume that a pointer dereference will yield
3877 non-NULL if -fdelete-null-pointer-checks is enabled. */
3878 if (flag_delete_null_pointer_checks
3879 && POINTER_TYPE_P (TREE_TYPE (op))
3880 && gimple_code (stmt) != GIMPLE_ASM)
3882 unsigned num_uses, num_loads, num_stores;
3884 count_uses_and_derefs (op, stmt, &num_uses, &num_loads, &num_stores);
3885 if (num_loads + num_stores > 0)
3887 *val_p = build_int_cst (TREE_TYPE (op), 0);
3888 *comp_code_p = NE_EXPR;
3897 void dump_asserts_for (FILE *, tree);
3898 void debug_asserts_for (tree);
3899 void dump_all_asserts (FILE *);
3900 void debug_all_asserts (void);
3902 /* Dump all the registered assertions for NAME to FILE. */
3905 dump_asserts_for (FILE *file, tree name)
3909 fprintf (file, "Assertions to be inserted for ");
3910 print_generic_expr (file, name, 0);
3911 fprintf (file, "\n");
3913 loc = asserts_for[SSA_NAME_VERSION (name)];
3916 fprintf (file, "\t");
3917 print_gimple_stmt (file, gsi_stmt (loc->si), 0, 0);
3918 fprintf (file, "\n\tBB #%d", loc->bb->index);
3921 fprintf (file, "\n\tEDGE %d->%d", loc->e->src->index,
3922 loc->e->dest->index);
3923 dump_edge_info (file, loc->e, 0);
3925 fprintf (file, "\n\tPREDICATE: ");
3926 print_generic_expr (file, name, 0);
3927 fprintf (file, " %s ", tree_code_name[(int)loc->comp_code]);
3928 print_generic_expr (file, loc->val, 0);
3929 fprintf (file, "\n\n");
3933 fprintf (file, "\n");
3937 /* Dump all the registered assertions for NAME to stderr. */
3940 debug_asserts_for (tree name)
3942 dump_asserts_for (stderr, name);
3946 /* Dump all the registered assertions for all the names to FILE. */
3949 dump_all_asserts (FILE *file)
3954 fprintf (file, "\nASSERT_EXPRs to be inserted\n\n");
3955 EXECUTE_IF_SET_IN_BITMAP (need_assert_for, 0, i, bi)
3956 dump_asserts_for (file, ssa_name (i));
3957 fprintf (file, "\n");
3961 /* Dump all the registered assertions for all the names to stderr. */
3964 debug_all_asserts (void)
3966 dump_all_asserts (stderr);
3970 /* If NAME doesn't have an ASSERT_EXPR registered for asserting
3971 'EXPR COMP_CODE VAL' at a location that dominates block BB or
3972 E->DEST, then register this location as a possible insertion point
3973 for ASSERT_EXPR <NAME, EXPR COMP_CODE VAL>.
3975 BB, E and SI provide the exact insertion point for the new
3976 ASSERT_EXPR. If BB is NULL, then the ASSERT_EXPR is to be inserted
3977 on edge E. Otherwise, if E is NULL, the ASSERT_EXPR is inserted on
3978 BB. If SI points to a COND_EXPR or a SWITCH_EXPR statement, then E
3979 must not be NULL. */
3982 register_new_assert_for (tree name, tree expr,
3983 enum tree_code comp_code,
3987 gimple_stmt_iterator si)
3989 assert_locus_t n, loc, last_loc;
3990 basic_block dest_bb;
3992 #if defined ENABLE_CHECKING
3993 gcc_assert (bb == NULL || e == NULL);
3996 gcc_assert (gimple_code (gsi_stmt (si)) != GIMPLE_COND
3997 && gimple_code (gsi_stmt (si)) != GIMPLE_SWITCH);
4000 /* Never build an assert comparing against an integer constant with
4001 TREE_OVERFLOW set. This confuses our undefined overflow warning
4003 if (TREE_CODE (val) == INTEGER_CST
4004 && TREE_OVERFLOW (val))
4005 val = build_int_cst_wide (TREE_TYPE (val),
4006 TREE_INT_CST_LOW (val), TREE_INT_CST_HIGH (val));
4008 /* The new assertion A will be inserted at BB or E. We need to
4009 determine if the new location is dominated by a previously
4010 registered location for A. If we are doing an edge insertion,
4011 assume that A will be inserted at E->DEST. Note that this is not
4014 If E is a critical edge, it will be split. But even if E is
4015 split, the new block will dominate the same set of blocks that
4018 The reverse, however, is not true, blocks dominated by E->DEST
4019 will not be dominated by the new block created to split E. So,
4020 if the insertion location is on a critical edge, we will not use
4021 the new location to move another assertion previously registered
4022 at a block dominated by E->DEST. */
4023 dest_bb = (bb) ? bb : e->dest;
4025 /* If NAME already has an ASSERT_EXPR registered for COMP_CODE and
4026 VAL at a block dominating DEST_BB, then we don't need to insert a new
4027 one. Similarly, if the same assertion already exists at a block
4028 dominated by DEST_BB and the new location is not on a critical
4029 edge, then update the existing location for the assertion (i.e.,
4030 move the assertion up in the dominance tree).
4032 Note, this is implemented as a simple linked list because there
4033 should not be more than a handful of assertions registered per
4034 name. If this becomes a performance problem, a table hashed by
4035 COMP_CODE and VAL could be implemented. */
4036 loc = asserts_for[SSA_NAME_VERSION (name)];
4040 if (loc->comp_code == comp_code
4042 || operand_equal_p (loc->val, val, 0))
4043 && (loc->expr == expr
4044 || operand_equal_p (loc->expr, expr, 0)))
4046 /* If the assertion NAME COMP_CODE VAL has already been
4047 registered at a basic block that dominates DEST_BB, then
4048 we don't need to insert the same assertion again. Note
4049 that we don't check strict dominance here to avoid
4050 replicating the same assertion inside the same basic
4051 block more than once (e.g., when a pointer is
4052 dereferenced several times inside a block).
4054 An exception to this rule are edge insertions. If the
4055 new assertion is to be inserted on edge E, then it will
4056 dominate all the other insertions that we may want to
4057 insert in DEST_BB. So, if we are doing an edge
4058 insertion, don't do this dominance check. */
4060 && dominated_by_p (CDI_DOMINATORS, dest_bb, loc->bb))
4063 /* Otherwise, if E is not a critical edge and DEST_BB
4064 dominates the existing location for the assertion, move
4065 the assertion up in the dominance tree by updating its
4066 location information. */
4067 if ((e == NULL || !EDGE_CRITICAL_P (e))
4068 && dominated_by_p (CDI_DOMINATORS, loc->bb, dest_bb))
4077 /* Update the last node of the list and move to the next one. */
4082 /* If we didn't find an assertion already registered for
4083 NAME COMP_CODE VAL, add a new one at the end of the list of
4084 assertions associated with NAME. */
4085 n = XNEW (struct assert_locus_d);
4089 n->comp_code = comp_code;
4097 asserts_for[SSA_NAME_VERSION (name)] = n;
4099 bitmap_set_bit (need_assert_for, SSA_NAME_VERSION (name));
4102 /* (COND_OP0 COND_CODE COND_OP1) is a predicate which uses NAME.
4103 Extract a suitable test code and value and store them into *CODE_P and
4104 *VAL_P so the predicate is normalized to NAME *CODE_P *VAL_P.
4106 If no extraction was possible, return FALSE, otherwise return TRUE.
4108 If INVERT is true, then we invert the result stored into *CODE_P. */
4111 extract_code_and_val_from_cond_with_ops (tree name, enum tree_code cond_code,
4112 tree cond_op0, tree cond_op1,
4113 bool invert, enum tree_code *code_p,
4116 enum tree_code comp_code;
4119 /* Otherwise, we have a comparison of the form NAME COMP VAL
4120 or VAL COMP NAME. */
4121 if (name == cond_op1)
4123 /* If the predicate is of the form VAL COMP NAME, flip
4124 COMP around because we need to register NAME as the
4125 first operand in the predicate. */
4126 comp_code = swap_tree_comparison (cond_code);
4131 /* The comparison is of the form NAME COMP VAL, so the
4132 comparison code remains unchanged. */
4133 comp_code = cond_code;
4137 /* Invert the comparison code as necessary. */
4139 comp_code = invert_tree_comparison (comp_code, 0);
4141 /* VRP does not handle float types. */
4142 if (SCALAR_FLOAT_TYPE_P (TREE_TYPE (val)))
4145 /* Do not register always-false predicates.
4146 FIXME: this works around a limitation in fold() when dealing with
4147 enumerations. Given 'enum { N1, N2 } x;', fold will not
4148 fold 'if (x > N2)' to 'if (0)'. */
4149 if ((comp_code == GT_EXPR || comp_code == LT_EXPR)
4150 && INTEGRAL_TYPE_P (TREE_TYPE (val)))
4152 tree min = TYPE_MIN_VALUE (TREE_TYPE (val));
4153 tree max = TYPE_MAX_VALUE (TREE_TYPE (val));
4155 if (comp_code == GT_EXPR
4157 || compare_values (val, max) == 0))
4160 if (comp_code == LT_EXPR
4162 || compare_values (val, min) == 0))
4165 *code_p = comp_code;
4170 /* Try to register an edge assertion for SSA name NAME on edge E for
4171 the condition COND contributing to the conditional jump pointed to by BSI.
4172 Invert the condition COND if INVERT is true.
4173 Return true if an assertion for NAME could be registered. */
4176 register_edge_assert_for_2 (tree name, edge e, gimple_stmt_iterator bsi,
4177 enum tree_code cond_code,
4178 tree cond_op0, tree cond_op1, bool invert)
4181 enum tree_code comp_code;
4182 bool retval = false;
4184 if (!extract_code_and_val_from_cond_with_ops (name, cond_code,
4187 invert, &comp_code, &val))
4190 /* Only register an ASSERT_EXPR if NAME was found in the sub-graph
4191 reachable from E. */
4192 if (live_on_edge (e, name)
4193 && !has_single_use (name))
4195 register_new_assert_for (name, name, comp_code, val, NULL, e, bsi);
4199 /* In the case of NAME <= CST and NAME being defined as
4200 NAME = (unsigned) NAME2 + CST2 we can assert NAME2 >= -CST2
4201 and NAME2 <= CST - CST2. We can do the same for NAME > CST.
4202 This catches range and anti-range tests. */
4203 if ((comp_code == LE_EXPR
4204 || comp_code == GT_EXPR)
4205 && TREE_CODE (val) == INTEGER_CST
4206 && TYPE_UNSIGNED (TREE_TYPE (val)))
4208 gimple def_stmt = SSA_NAME_DEF_STMT (name);
4209 tree cst2 = NULL_TREE, name2 = NULL_TREE, name3 = NULL_TREE;
4211 /* Extract CST2 from the (optional) addition. */
4212 if (is_gimple_assign (def_stmt)
4213 && gimple_assign_rhs_code (def_stmt) == PLUS_EXPR)
4215 name2 = gimple_assign_rhs1 (def_stmt);
4216 cst2 = gimple_assign_rhs2 (def_stmt);
4217 if (TREE_CODE (name2) == SSA_NAME
4218 && TREE_CODE (cst2) == INTEGER_CST)
4219 def_stmt = SSA_NAME_DEF_STMT (name2);
4222 /* Extract NAME2 from the (optional) sign-changing cast. */
4223 if (gimple_assign_cast_p (def_stmt))
4225 if (CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (def_stmt))
4226 && ! TYPE_UNSIGNED (TREE_TYPE (gimple_assign_rhs1 (def_stmt)))
4227 && (TYPE_PRECISION (gimple_expr_type (def_stmt))
4228 == TYPE_PRECISION (TREE_TYPE (gimple_assign_rhs1 (def_stmt)))))
4229 name3 = gimple_assign_rhs1 (def_stmt);
4232 /* If name3 is used later, create an ASSERT_EXPR for it. */
4233 if (name3 != NULL_TREE
4234 && TREE_CODE (name3) == SSA_NAME
4235 && (cst2 == NULL_TREE
4236 || TREE_CODE (cst2) == INTEGER_CST)
4237 && INTEGRAL_TYPE_P (TREE_TYPE (name3))
4238 && live_on_edge (e, name3)
4239 && !has_single_use (name3))
4243 /* Build an expression for the range test. */
4244 tmp = build1 (NOP_EXPR, TREE_TYPE (name), name3);
4245 if (cst2 != NULL_TREE)
4246 tmp = build2 (PLUS_EXPR, TREE_TYPE (name), tmp, cst2);
4250 fprintf (dump_file, "Adding assert for ");
4251 print_generic_expr (dump_file, name3, 0);
4252 fprintf (dump_file, " from ");
4253 print_generic_expr (dump_file, tmp, 0);
4254 fprintf (dump_file, "\n");
4257 register_new_assert_for (name3, tmp, comp_code, val, NULL, e, bsi);
4262 /* If name2 is used later, create an ASSERT_EXPR for it. */
4263 if (name2 != NULL_TREE
4264 && TREE_CODE (name2) == SSA_NAME
4265 && TREE_CODE (cst2) == INTEGER_CST
4266 && INTEGRAL_TYPE_P (TREE_TYPE (name2))
4267 && live_on_edge (e, name2)
4268 && !has_single_use (name2))
4272 /* Build an expression for the range test. */
4274 if (TREE_TYPE (name) != TREE_TYPE (name2))
4275 tmp = build1 (NOP_EXPR, TREE_TYPE (name), tmp);
4276 if (cst2 != NULL_TREE)
4277 tmp = build2 (PLUS_EXPR, TREE_TYPE (name), tmp, cst2);
4281 fprintf (dump_file, "Adding assert for ");
4282 print_generic_expr (dump_file, name2, 0);
4283 fprintf (dump_file, " from ");
4284 print_generic_expr (dump_file, tmp, 0);
4285 fprintf (dump_file, "\n");
4288 register_new_assert_for (name2, tmp, comp_code, val, NULL, e, bsi);
4297 /* OP is an operand of a truth value expression which is known to have
4298 a particular value. Register any asserts for OP and for any
4299 operands in OP's defining statement.
4301 If CODE is EQ_EXPR, then we want to register OP is zero (false),
4302 if CODE is NE_EXPR, then we want to register OP is nonzero (true). */
4305 register_edge_assert_for_1 (tree op, enum tree_code code,
4306 edge e, gimple_stmt_iterator bsi)
4308 bool retval = false;
4311 enum tree_code rhs_code;
4313 /* We only care about SSA_NAMEs. */
4314 if (TREE_CODE (op) != SSA_NAME)
4317 /* We know that OP will have a zero or nonzero value. If OP is used
4318 more than once go ahead and register an assert for OP.
4320 The FOUND_IN_SUBGRAPH support is not helpful in this situation as
4321 it will always be set for OP (because OP is used in a COND_EXPR in
4323 if (!has_single_use (op))
4325 val = build_int_cst (TREE_TYPE (op), 0);
4326 register_new_assert_for (op, op, code, val, NULL, e, bsi);
4330 /* Now look at how OP is set. If it's set from a comparison,
4331 a truth operation or some bit operations, then we may be able
4332 to register information about the operands of that assignment. */
4333 op_def = SSA_NAME_DEF_STMT (op);
4334 if (gimple_code (op_def) != GIMPLE_ASSIGN)
4337 rhs_code = gimple_assign_rhs_code (op_def);
4339 if (TREE_CODE_CLASS (rhs_code) == tcc_comparison)
4341 bool invert = (code == EQ_EXPR ? true : false);
4342 tree op0 = gimple_assign_rhs1 (op_def);
4343 tree op1 = gimple_assign_rhs2 (op_def);
4345 if (TREE_CODE (op0) == SSA_NAME)
4346 retval |= register_edge_assert_for_2 (op0, e, bsi, rhs_code, op0, op1,
4348 if (TREE_CODE (op1) == SSA_NAME)
4349 retval |= register_edge_assert_for_2 (op1, e, bsi, rhs_code, op0, op1,
4352 else if ((code == NE_EXPR
4353 && (gimple_assign_rhs_code (op_def) == TRUTH_AND_EXPR
4354 || gimple_assign_rhs_code (op_def) == BIT_AND_EXPR))
4356 && (gimple_assign_rhs_code (op_def) == TRUTH_OR_EXPR
4357 || gimple_assign_rhs_code (op_def) == BIT_IOR_EXPR)))
4359 /* Recurse on each operand. */
4360 retval |= register_edge_assert_for_1 (gimple_assign_rhs1 (op_def),
4362 retval |= register_edge_assert_for_1 (gimple_assign_rhs2 (op_def),
4365 else if (gimple_assign_rhs_code (op_def) == TRUTH_NOT_EXPR)
4367 /* Recurse, flipping CODE. */
4368 code = invert_tree_comparison (code, false);
4369 retval |= register_edge_assert_for_1 (gimple_assign_rhs1 (op_def),
4372 else if (gimple_assign_rhs_code (op_def) == SSA_NAME)
4374 /* Recurse through the copy. */
4375 retval |= register_edge_assert_for_1 (gimple_assign_rhs1 (op_def),
4378 else if (CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (op_def)))
4380 /* Recurse through the type conversion. */
4381 retval |= register_edge_assert_for_1 (gimple_assign_rhs1 (op_def),
4388 /* Try to register an edge assertion for SSA name NAME on edge E for
4389 the condition COND contributing to the conditional jump pointed to by SI.
4390 Return true if an assertion for NAME could be registered. */
4393 register_edge_assert_for (tree name, edge e, gimple_stmt_iterator si,
4394 enum tree_code cond_code, tree cond_op0,
4398 enum tree_code comp_code;
4399 bool retval = false;
4400 bool is_else_edge = (e->flags & EDGE_FALSE_VALUE) != 0;
4402 /* Do not attempt to infer anything in names that flow through
4404 if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (name))
4407 if (!extract_code_and_val_from_cond_with_ops (name, cond_code,
4413 /* Register ASSERT_EXPRs for name. */
4414 retval |= register_edge_assert_for_2 (name, e, si, cond_code, cond_op0,
4415 cond_op1, is_else_edge);
4418 /* If COND is effectively an equality test of an SSA_NAME against
4419 the value zero or one, then we may be able to assert values
4420 for SSA_NAMEs which flow into COND. */
4422 /* In the case of NAME == 1 or NAME != 0, for TRUTH_AND_EXPR defining
4423 statement of NAME we can assert both operands of the TRUTH_AND_EXPR
4424 have nonzero value. */
4425 if (((comp_code == EQ_EXPR && integer_onep (val))
4426 || (comp_code == NE_EXPR && integer_zerop (val))))
4428 gimple def_stmt = SSA_NAME_DEF_STMT (name);
4430 if (is_gimple_assign (def_stmt)
4431 && (gimple_assign_rhs_code (def_stmt) == TRUTH_AND_EXPR
4432 || gimple_assign_rhs_code (def_stmt) == BIT_AND_EXPR))
4434 tree op0 = gimple_assign_rhs1 (def_stmt);
4435 tree op1 = gimple_assign_rhs2 (def_stmt);
4436 retval |= register_edge_assert_for_1 (op0, NE_EXPR, e, si);
4437 retval |= register_edge_assert_for_1 (op1, NE_EXPR, e, si);
4441 /* In the case of NAME == 0 or NAME != 1, for TRUTH_OR_EXPR defining
4442 statement of NAME we can assert both operands of the TRUTH_OR_EXPR
4444 if (((comp_code == EQ_EXPR && integer_zerop (val))
4445 || (comp_code == NE_EXPR && integer_onep (val))))
4447 gimple def_stmt = SSA_NAME_DEF_STMT (name);
4449 if (is_gimple_assign (def_stmt)
4450 && (gimple_assign_rhs_code (def_stmt) == TRUTH_OR_EXPR
4451 /* For BIT_IOR_EXPR only if NAME == 0 both operands have
4452 necessarily zero value. */
4453 || (comp_code == EQ_EXPR
4454 && (gimple_assign_rhs_code (def_stmt) == BIT_IOR_EXPR))))
4456 tree op0 = gimple_assign_rhs1 (def_stmt);
4457 tree op1 = gimple_assign_rhs2 (def_stmt);
4458 retval |= register_edge_assert_for_1 (op0, EQ_EXPR, e, si);
4459 retval |= register_edge_assert_for_1 (op1, EQ_EXPR, e, si);
4467 /* Determine whether the outgoing edges of BB should receive an
4468 ASSERT_EXPR for each of the operands of BB's LAST statement.
4469 The last statement of BB must be a COND_EXPR.
4471 If any of the sub-graphs rooted at BB have an interesting use of
4472 the predicate operands, an assert location node is added to the
4473 list of assertions for the corresponding operands. */
4476 find_conditional_asserts (basic_block bb, gimple last)
4479 gimple_stmt_iterator bsi;
4485 need_assert = false;
4486 bsi = gsi_for_stmt (last);
4488 /* Look for uses of the operands in each of the sub-graphs
4489 rooted at BB. We need to check each of the outgoing edges
4490 separately, so that we know what kind of ASSERT_EXPR to
4492 FOR_EACH_EDGE (e, ei, bb->succs)
4497 /* Register the necessary assertions for each operand in the
4498 conditional predicate. */
4499 FOR_EACH_SSA_TREE_OPERAND (op, last, iter, SSA_OP_USE)
4501 need_assert |= register_edge_assert_for (op, e, bsi,
4502 gimple_cond_code (last),
4503 gimple_cond_lhs (last),
4504 gimple_cond_rhs (last));
4511 /* Compare two case labels sorting first by the destination label uid
4512 and then by the case value. */
4515 compare_case_labels (const void *p1, const void *p2)
4517 const_tree const case1 = *(const_tree const*)p1;
4518 const_tree const case2 = *(const_tree const*)p2;
4519 unsigned int uid1 = DECL_UID (CASE_LABEL (case1));
4520 unsigned int uid2 = DECL_UID (CASE_LABEL (case2));
4524 else if (uid1 == uid2)
4526 /* Make sure the default label is first in a group. */
4527 if (!CASE_LOW (case1))
4529 else if (!CASE_LOW (case2))
4532 return tree_int_cst_compare (CASE_LOW (case1), CASE_LOW (case2));
4538 /* Determine whether the outgoing edges of BB should receive an
4539 ASSERT_EXPR for each of the operands of BB's LAST statement.
4540 The last statement of BB must be a SWITCH_EXPR.
4542 If any of the sub-graphs rooted at BB have an interesting use of
4543 the predicate operands, an assert location node is added to the
4544 list of assertions for the corresponding operands. */
4547 find_switch_asserts (basic_block bb, gimple last)
4550 gimple_stmt_iterator bsi;
4554 size_t n = gimple_switch_num_labels(last);
4555 #if GCC_VERSION >= 4000
4558 /* Work around GCC 3.4 bug (PR 37086). */
4559 volatile unsigned int idx;
4562 need_assert = false;
4563 bsi = gsi_for_stmt (last);
4564 op = gimple_switch_index (last);
4565 if (TREE_CODE (op) != SSA_NAME)
4568 /* Build a vector of case labels sorted by destination label. */
4569 vec2 = make_tree_vec (n);
4570 for (idx = 0; idx < n; ++idx)
4571 TREE_VEC_ELT (vec2, idx) = gimple_switch_label (last, idx);
4572 qsort (&TREE_VEC_ELT (vec2, 0), n, sizeof (tree), compare_case_labels);
4574 for (idx = 0; idx < n; ++idx)
4577 tree cl = TREE_VEC_ELT (vec2, idx);
4579 min = CASE_LOW (cl);
4580 max = CASE_HIGH (cl);
4582 /* If there are multiple case labels with the same destination
4583 we need to combine them to a single value range for the edge. */
4585 && CASE_LABEL (cl) == CASE_LABEL (TREE_VEC_ELT (vec2, idx + 1)))
4587 /* Skip labels until the last of the group. */
4591 && CASE_LABEL (cl) == CASE_LABEL (TREE_VEC_ELT (vec2, idx)));
4594 /* Pick up the maximum of the case label range. */
4595 if (CASE_HIGH (TREE_VEC_ELT (vec2, idx)))
4596 max = CASE_HIGH (TREE_VEC_ELT (vec2, idx));
4598 max = CASE_LOW (TREE_VEC_ELT (vec2, idx));
4601 /* Nothing to do if the range includes the default label until we
4602 can register anti-ranges. */
4603 if (min == NULL_TREE)
4606 /* Find the edge to register the assert expr on. */
4607 e = find_edge (bb, label_to_block (CASE_LABEL (cl)));
4609 /* Register the necessary assertions for the operand in the
4611 need_assert |= register_edge_assert_for (op, e, bsi,
4612 max ? GE_EXPR : EQ_EXPR,
4614 fold_convert (TREE_TYPE (op),
4618 need_assert |= register_edge_assert_for (op, e, bsi, LE_EXPR,
4620 fold_convert (TREE_TYPE (op),
4629 /* Traverse all the statements in block BB looking for statements that
4630 may generate useful assertions for the SSA names in their operand.
4631 If a statement produces a useful assertion A for name N_i, then the
4632 list of assertions already generated for N_i is scanned to
4633 determine if A is actually needed.
4635 If N_i already had the assertion A at a location dominating the
4636 current location, then nothing needs to be done. Otherwise, the
4637 new location for A is recorded instead.
4639 1- For every statement S in BB, all the variables used by S are
4640 added to bitmap FOUND_IN_SUBGRAPH.
4642 2- If statement S uses an operand N in a way that exposes a known
4643 value range for N, then if N was not already generated by an
4644 ASSERT_EXPR, create a new assert location for N. For instance,
4645 if N is a pointer and the statement dereferences it, we can
4646 assume that N is not NULL.
4648 3- COND_EXPRs are a special case of #2. We can derive range
4649 information from the predicate but need to insert different
4650 ASSERT_EXPRs for each of the sub-graphs rooted at the
4651 conditional block. If the last statement of BB is a conditional
4652 expression of the form 'X op Y', then
4654 a) Remove X and Y from the set FOUND_IN_SUBGRAPH.
4656 b) If the conditional is the only entry point to the sub-graph
4657 corresponding to the THEN_CLAUSE, recurse into it. On
4658 return, if X and/or Y are marked in FOUND_IN_SUBGRAPH, then
4659 an ASSERT_EXPR is added for the corresponding variable.
4661 c) Repeat step (b) on the ELSE_CLAUSE.
4663 d) Mark X and Y in FOUND_IN_SUBGRAPH.
4672 In this case, an assertion on the THEN clause is useful to
4673 determine that 'a' is always 9 on that edge. However, an assertion
4674 on the ELSE clause would be unnecessary.
4676 4- If BB does not end in a conditional expression, then we recurse
4677 into BB's dominator children.
4679 At the end of the recursive traversal, every SSA name will have a
4680 list of locations where ASSERT_EXPRs should be added. When a new
4681 location for name N is found, it is registered by calling
4682 register_new_assert_for. That function keeps track of all the
4683 registered assertions to prevent adding unnecessary assertions.
4684 For instance, if a pointer P_4 is dereferenced more than once in a
4685 dominator tree, only the location dominating all the dereference of
4686 P_4 will receive an ASSERT_EXPR.
4688 If this function returns true, then it means that there are names
4689 for which we need to generate ASSERT_EXPRs. Those assertions are
4690 inserted by process_assert_insertions. */
4693 find_assert_locations_1 (basic_block bb, sbitmap live)
4695 gimple_stmt_iterator si;
4700 need_assert = false;
4701 last = last_stmt (bb);
4703 /* If BB's last statement is a conditional statement involving integer
4704 operands, determine if we need to add ASSERT_EXPRs. */
4706 && gimple_code (last) == GIMPLE_COND
4707 && !fp_predicate (last)
4708 && !ZERO_SSA_OPERANDS (last, SSA_OP_USE))
4709 need_assert |= find_conditional_asserts (bb, last);
4711 /* If BB's last statement is a switch statement involving integer
4712 operands, determine if we need to add ASSERT_EXPRs. */
4714 && gimple_code (last) == GIMPLE_SWITCH
4715 && !ZERO_SSA_OPERANDS (last, SSA_OP_USE))
4716 need_assert |= find_switch_asserts (bb, last);
4718 /* Traverse all the statements in BB marking used names and looking
4719 for statements that may infer assertions for their used operands. */
4720 for (si = gsi_start_bb (bb); !gsi_end_p (si); gsi_next (&si))
4726 stmt = gsi_stmt (si);
4728 if (is_gimple_debug (stmt))
4731 /* See if we can derive an assertion for any of STMT's operands. */
4732 FOR_EACH_SSA_TREE_OPERAND (op, stmt, i, SSA_OP_USE)
4735 enum tree_code comp_code;
4737 /* Mark OP in our live bitmap. */
4738 SET_BIT (live, SSA_NAME_VERSION (op));
4740 /* If OP is used in such a way that we can infer a value
4741 range for it, and we don't find a previous assertion for
4742 it, create a new assertion location node for OP. */
4743 if (infer_value_range (stmt, op, &comp_code, &value))
4745 /* If we are able to infer a nonzero value range for OP,
4746 then walk backwards through the use-def chain to see if OP
4747 was set via a typecast.
4749 If so, then we can also infer a nonzero value range
4750 for the operand of the NOP_EXPR. */
4751 if (comp_code == NE_EXPR && integer_zerop (value))
4754 gimple def_stmt = SSA_NAME_DEF_STMT (t);
4756 while (is_gimple_assign (def_stmt)
4757 && gimple_assign_rhs_code (def_stmt) == NOP_EXPR
4759 (gimple_assign_rhs1 (def_stmt)) == SSA_NAME
4761 (TREE_TYPE (gimple_assign_rhs1 (def_stmt))))
4763 t = gimple_assign_rhs1 (def_stmt);
4764 def_stmt = SSA_NAME_DEF_STMT (t);
4766 /* Note we want to register the assert for the
4767 operand of the NOP_EXPR after SI, not after the
4769 if (! has_single_use (t))
4771 register_new_assert_for (t, t, comp_code, value,
4778 /* If OP is used only once, namely in this STMT, don't
4779 bother creating an ASSERT_EXPR for it. Such an
4780 ASSERT_EXPR would do nothing but increase compile time. */
4781 if (!has_single_use (op))
4783 register_new_assert_for (op, op, comp_code, value,
4791 /* Traverse all PHI nodes in BB marking used operands. */
4792 for (si = gsi_start_phis (bb); !gsi_end_p(si); gsi_next (&si))
4794 use_operand_p arg_p;
4796 phi = gsi_stmt (si);
4798 FOR_EACH_PHI_ARG (arg_p, phi, i, SSA_OP_USE)
4800 tree arg = USE_FROM_PTR (arg_p);
4801 if (TREE_CODE (arg) == SSA_NAME)
4802 SET_BIT (live, SSA_NAME_VERSION (arg));
4809 /* Do an RPO walk over the function computing SSA name liveness
4810 on-the-fly and deciding on assert expressions to insert.
4811 Returns true if there are assert expressions to be inserted. */
4814 find_assert_locations (void)
4816 int *rpo = XCNEWVEC (int, last_basic_block + NUM_FIXED_BLOCKS);
4817 int *bb_rpo = XCNEWVEC (int, last_basic_block + NUM_FIXED_BLOCKS);
4818 int *last_rpo = XCNEWVEC (int, last_basic_block + NUM_FIXED_BLOCKS);
4822 live = XCNEWVEC (sbitmap, last_basic_block + NUM_FIXED_BLOCKS);
4823 rpo_cnt = pre_and_rev_post_order_compute (NULL, rpo, false);
4824 for (i = 0; i < rpo_cnt; ++i)
4827 need_asserts = false;
4828 for (i = rpo_cnt-1; i >= 0; --i)
4830 basic_block bb = BASIC_BLOCK (rpo[i]);
4836 live[rpo[i]] = sbitmap_alloc (num_ssa_names);
4837 sbitmap_zero (live[rpo[i]]);
4840 /* Process BB and update the live information with uses in
4842 need_asserts |= find_assert_locations_1 (bb, live[rpo[i]]);
4844 /* Merge liveness into the predecessor blocks and free it. */
4845 if (!sbitmap_empty_p (live[rpo[i]]))
4848 FOR_EACH_EDGE (e, ei, bb->preds)
4850 int pred = e->src->index;
4851 if (e->flags & EDGE_DFS_BACK)
4856 live[pred] = sbitmap_alloc (num_ssa_names);
4857 sbitmap_zero (live[pred]);
4859 sbitmap_a_or_b (live[pred], live[pred], live[rpo[i]]);
4861 if (bb_rpo[pred] < pred_rpo)
4862 pred_rpo = bb_rpo[pred];
4865 /* Record the RPO number of the last visited block that needs
4866 live information from this block. */
4867 last_rpo[rpo[i]] = pred_rpo;
4871 sbitmap_free (live[rpo[i]]);
4872 live[rpo[i]] = NULL;
4875 /* We can free all successors live bitmaps if all their
4876 predecessors have been visited already. */
4877 FOR_EACH_EDGE (e, ei, bb->succs)
4878 if (last_rpo[e->dest->index] == i
4879 && live[e->dest->index])
4881 sbitmap_free (live[e->dest->index]);
4882 live[e->dest->index] = NULL;
4887 XDELETEVEC (bb_rpo);
4888 XDELETEVEC (last_rpo);
4889 for (i = 0; i < last_basic_block + NUM_FIXED_BLOCKS; ++i)
4891 sbitmap_free (live[i]);
4894 return need_asserts;
4897 /* Create an ASSERT_EXPR for NAME and insert it in the location
4898 indicated by LOC. Return true if we made any edge insertions. */
4901 process_assert_insertions_for (tree name, assert_locus_t loc)
4903 /* Build the comparison expression NAME_i COMP_CODE VAL. */
4910 /* If we have X <=> X do not insert an assert expr for that. */
4911 if (loc->expr == loc->val)
4914 cond = build2 (loc->comp_code, boolean_type_node, loc->expr, loc->val);
4915 assert_stmt = build_assert_expr_for (cond, name);
4918 /* We have been asked to insert the assertion on an edge. This
4919 is used only by COND_EXPR and SWITCH_EXPR assertions. */
4920 #if defined ENABLE_CHECKING
4921 gcc_assert (gimple_code (gsi_stmt (loc->si)) == GIMPLE_COND
4922 || gimple_code (gsi_stmt (loc->si)) == GIMPLE_SWITCH);
4925 gsi_insert_on_edge (loc->e, assert_stmt);
4929 /* Otherwise, we can insert right after LOC->SI iff the
4930 statement must not be the last statement in the block. */
4931 stmt = gsi_stmt (loc->si);
4932 if (!stmt_ends_bb_p (stmt))
4934 gsi_insert_after (&loc->si, assert_stmt, GSI_SAME_STMT);
4938 /* If STMT must be the last statement in BB, we can only insert new
4939 assertions on the non-abnormal edge out of BB. Note that since
4940 STMT is not control flow, there may only be one non-abnormal edge
4942 FOR_EACH_EDGE (e, ei, loc->bb->succs)
4943 if (!(e->flags & EDGE_ABNORMAL))
4945 gsi_insert_on_edge (e, assert_stmt);
4953 /* Process all the insertions registered for every name N_i registered
4954 in NEED_ASSERT_FOR. The list of assertions to be inserted are
4955 found in ASSERTS_FOR[i]. */
4958 process_assert_insertions (void)
4962 bool update_edges_p = false;
4963 int num_asserts = 0;
4965 if (dump_file && (dump_flags & TDF_DETAILS))
4966 dump_all_asserts (dump_file);
4968 EXECUTE_IF_SET_IN_BITMAP (need_assert_for, 0, i, bi)
4970 assert_locus_t loc = asserts_for[i];
4975 assert_locus_t next = loc->next;
4976 update_edges_p |= process_assert_insertions_for (ssa_name (i), loc);
4984 gsi_commit_edge_inserts ();
4986 statistics_counter_event (cfun, "Number of ASSERT_EXPR expressions inserted",
4991 /* Traverse the flowgraph looking for conditional jumps to insert range
4992 expressions. These range expressions are meant to provide information
4993 to optimizations that need to reason in terms of value ranges. They
4994 will not be expanded into RTL. For instance, given:
5003 this pass will transform the code into:
5009 x = ASSERT_EXPR <x, x < y>
5014 y = ASSERT_EXPR <y, x <= y>
5018 The idea is that once copy and constant propagation have run, other
5019 optimizations will be able to determine what ranges of values can 'x'
5020 take in different paths of the code, simply by checking the reaching
5021 definition of 'x'. */
5024 insert_range_assertions (void)
5026 need_assert_for = BITMAP_ALLOC (NULL);
5027 asserts_for = XCNEWVEC (assert_locus_t, num_ssa_names);
5029 calculate_dominance_info (CDI_DOMINATORS);
5031 if (find_assert_locations ())
5033 process_assert_insertions ();
5034 update_ssa (TODO_update_ssa_no_phi);
5037 if (dump_file && (dump_flags & TDF_DETAILS))
5039 fprintf (dump_file, "\nSSA form after inserting ASSERT_EXPRs\n");
5040 dump_function_to_file (current_function_decl, dump_file, dump_flags);
5044 BITMAP_FREE (need_assert_for);
5047 /* Checks one ARRAY_REF in REF, located at LOCUS. Ignores flexible arrays
5048 and "struct" hacks. If VRP can determine that the
5049 array subscript is a constant, check if it is outside valid
5050 range. If the array subscript is a RANGE, warn if it is
5051 non-overlapping with valid range.
5052 IGNORE_OFF_BY_ONE is true if the ARRAY_REF is inside a ADDR_EXPR. */
5055 check_array_ref (location_t location, tree ref, bool ignore_off_by_one)
5057 value_range_t* vr = NULL;
5058 tree low_sub, up_sub;
5059 tree low_bound, up_bound, up_bound_p1;
5062 if (TREE_NO_WARNING (ref))
5065 low_sub = up_sub = TREE_OPERAND (ref, 1);
5066 up_bound = array_ref_up_bound (ref);
5068 /* Can not check flexible arrays. */
5070 || TREE_CODE (up_bound) != INTEGER_CST)
5073 /* Accesses to trailing arrays via pointers may access storage
5074 beyond the types array bounds. */
5075 base = get_base_address (ref);
5077 && INDIRECT_REF_P (base))
5079 tree cref, next = NULL_TREE;
5081 if (TREE_CODE (TREE_OPERAND (ref, 0)) != COMPONENT_REF)
5084 cref = TREE_OPERAND (ref, 0);
5085 if (TREE_CODE (TREE_TYPE (TREE_OPERAND (cref, 0))) == RECORD_TYPE)
5086 for (next = TREE_CHAIN (TREE_OPERAND (cref, 1));
5087 next && TREE_CODE (next) != FIELD_DECL;
5088 next = TREE_CHAIN (next))
5091 /* If this is the last field in a struct type or a field in a
5092 union type do not warn. */
5097 low_bound = array_ref_low_bound (ref);
5098 up_bound_p1 = int_const_binop (PLUS_EXPR, up_bound, integer_one_node, 0);
5100 if (TREE_CODE (low_sub) == SSA_NAME)
5102 vr = get_value_range (low_sub);
5103 if (vr->type == VR_RANGE || vr->type == VR_ANTI_RANGE)
5105 low_sub = vr->type == VR_RANGE ? vr->max : vr->min;
5106 up_sub = vr->type == VR_RANGE ? vr->min : vr->max;
5110 if (vr && vr->type == VR_ANTI_RANGE)
5112 if (TREE_CODE (up_sub) == INTEGER_CST
5113 && tree_int_cst_lt (up_bound, up_sub)
5114 && TREE_CODE (low_sub) == INTEGER_CST
5115 && tree_int_cst_lt (low_sub, low_bound))
5117 warning_at (location, OPT_Warray_bounds,
5118 "array subscript is outside array bounds");
5119 TREE_NO_WARNING (ref) = 1;
5122 else if (TREE_CODE (up_sub) == INTEGER_CST
5123 && (ignore_off_by_one
5124 ? (tree_int_cst_lt (up_bound, up_sub)
5125 && !tree_int_cst_equal (up_bound_p1, up_sub))
5126 : (tree_int_cst_lt (up_bound, up_sub)
5127 || tree_int_cst_equal (up_bound_p1, up_sub))))
5129 warning_at (location, OPT_Warray_bounds,
5130 "array subscript is above array bounds");
5131 TREE_NO_WARNING (ref) = 1;
5133 else if (TREE_CODE (low_sub) == INTEGER_CST
5134 && tree_int_cst_lt (low_sub, low_bound))
5136 warning_at (location, OPT_Warray_bounds,
5137 "array subscript is below array bounds");
5138 TREE_NO_WARNING (ref) = 1;
5142 /* Searches if the expr T, located at LOCATION computes
5143 address of an ARRAY_REF, and call check_array_ref on it. */
5146 search_for_addr_array (tree t, location_t location)
5148 while (TREE_CODE (t) == SSA_NAME)
5150 gimple g = SSA_NAME_DEF_STMT (t);
5152 if (gimple_code (g) != GIMPLE_ASSIGN)
5155 if (get_gimple_rhs_class (gimple_assign_rhs_code (g))
5156 != GIMPLE_SINGLE_RHS)
5159 t = gimple_assign_rhs1 (g);
5163 /* We are only interested in addresses of ARRAY_REF's. */
5164 if (TREE_CODE (t) != ADDR_EXPR)
5167 /* Check each ARRAY_REFs in the reference chain. */
5170 if (TREE_CODE (t) == ARRAY_REF)
5171 check_array_ref (location, t, true /*ignore_off_by_one*/);
5173 t = TREE_OPERAND (t, 0);
5175 while (handled_component_p (t));
5178 /* walk_tree() callback that checks if *TP is
5179 an ARRAY_REF inside an ADDR_EXPR (in which an array
5180 subscript one outside the valid range is allowed). Call
5181 check_array_ref for each ARRAY_REF found. The location is
5185 check_array_bounds (tree *tp, int *walk_subtree, void *data)
5188 struct walk_stmt_info *wi = (struct walk_stmt_info *) data;
5189 location_t location;
5191 if (EXPR_HAS_LOCATION (t))
5192 location = EXPR_LOCATION (t);
5195 location_t *locp = (location_t *) wi->info;
5199 *walk_subtree = TRUE;
5201 if (TREE_CODE (t) == ARRAY_REF)
5202 check_array_ref (location, t, false /*ignore_off_by_one*/);
5204 if (TREE_CODE (t) == INDIRECT_REF
5205 || (TREE_CODE (t) == RETURN_EXPR && TREE_OPERAND (t, 0)))
5206 search_for_addr_array (TREE_OPERAND (t, 0), location);
5208 if (TREE_CODE (t) == ADDR_EXPR)
5209 *walk_subtree = FALSE;
5214 /* Walk over all statements of all reachable BBs and call check_array_bounds
5218 check_all_array_refs (void)
5221 gimple_stmt_iterator si;
5227 bool executable = false;
5229 /* Skip blocks that were found to be unreachable. */
5230 FOR_EACH_EDGE (e, ei, bb->preds)
5231 executable |= !!(e->flags & EDGE_EXECUTABLE);
5235 for (si = gsi_start_bb (bb); !gsi_end_p (si); gsi_next (&si))
5237 gimple stmt = gsi_stmt (si);
5238 struct walk_stmt_info wi;
5239 if (!gimple_has_location (stmt))
5242 if (is_gimple_call (stmt))
5245 size_t n = gimple_call_num_args (stmt);
5246 for (i = 0; i < n; i++)
5248 tree arg = gimple_call_arg (stmt, i);
5249 search_for_addr_array (arg, gimple_location (stmt));
5254 memset (&wi, 0, sizeof (wi));
5255 wi.info = CONST_CAST (void *, (const void *)
5256 gimple_location_ptr (stmt));
5258 walk_gimple_op (gsi_stmt (si),
5266 /* Convert range assertion expressions into the implied copies and
5267 copy propagate away the copies. Doing the trivial copy propagation
5268 here avoids the need to run the full copy propagation pass after
5271 FIXME, this will eventually lead to copy propagation removing the
5272 names that had useful range information attached to them. For
5273 instance, if we had the assertion N_i = ASSERT_EXPR <N_j, N_j > 3>,
5274 then N_i will have the range [3, +INF].
5276 However, by converting the assertion into the implied copy
5277 operation N_i = N_j, we will then copy-propagate N_j into the uses
5278 of N_i and lose the range information. We may want to hold on to
5279 ASSERT_EXPRs a little while longer as the ranges could be used in
5280 things like jump threading.
5282 The problem with keeping ASSERT_EXPRs around is that passes after
5283 VRP need to handle them appropriately.
5285 Another approach would be to make the range information a first
5286 class property of the SSA_NAME so that it can be queried from
5287 any pass. This is made somewhat more complex by the need for
5288 multiple ranges to be associated with one SSA_NAME. */
5291 remove_range_assertions (void)
5294 gimple_stmt_iterator si;
5296 /* Note that the BSI iterator bump happens at the bottom of the
5297 loop and no bump is necessary if we're removing the statement
5298 referenced by the current BSI. */
5300 for (si = gsi_start_bb (bb); !gsi_end_p (si);)
5302 gimple stmt = gsi_stmt (si);
5305 if (is_gimple_assign (stmt)
5306 && gimple_assign_rhs_code (stmt) == ASSERT_EXPR)
5308 tree rhs = gimple_assign_rhs1 (stmt);
5310 tree cond = fold (ASSERT_EXPR_COND (rhs));
5311 use_operand_p use_p;
5312 imm_use_iterator iter;
5314 gcc_assert (cond != boolean_false_node);
5316 /* Propagate the RHS into every use of the LHS. */
5317 var = ASSERT_EXPR_VAR (rhs);
5318 FOR_EACH_IMM_USE_STMT (use_stmt, iter,
5319 gimple_assign_lhs (stmt))
5320 FOR_EACH_IMM_USE_ON_STMT (use_p, iter)
5322 SET_USE (use_p, var);
5323 gcc_assert (TREE_CODE (var) == SSA_NAME);
5326 /* And finally, remove the copy, it is not needed. */
5327 gsi_remove (&si, true);
5328 release_defs (stmt);
5336 /* Return true if STMT is interesting for VRP. */
5339 stmt_interesting_for_vrp (gimple stmt)
5341 if (gimple_code (stmt) == GIMPLE_PHI
5342 && is_gimple_reg (gimple_phi_result (stmt))
5343 && (INTEGRAL_TYPE_P (TREE_TYPE (gimple_phi_result (stmt)))
5344 || POINTER_TYPE_P (TREE_TYPE (gimple_phi_result (stmt)))))
5346 else if (is_gimple_assign (stmt) || is_gimple_call (stmt))
5348 tree lhs = gimple_get_lhs (stmt);
5350 /* In general, assignments with virtual operands are not useful
5351 for deriving ranges, with the obvious exception of calls to
5352 builtin functions. */
5353 if (lhs && TREE_CODE (lhs) == SSA_NAME
5354 && (INTEGRAL_TYPE_P (TREE_TYPE (lhs))
5355 || POINTER_TYPE_P (TREE_TYPE (lhs)))
5356 && ((is_gimple_call (stmt)
5357 && gimple_call_fndecl (stmt) != NULL_TREE
5358 && DECL_IS_BUILTIN (gimple_call_fndecl (stmt)))
5359 || !gimple_vuse (stmt)))
5362 else if (gimple_code (stmt) == GIMPLE_COND
5363 || gimple_code (stmt) == GIMPLE_SWITCH)
5370 /* Initialize local data structures for VRP. */
5373 vrp_initialize (void)
5377 vr_value = XCNEWVEC (value_range_t *, num_ssa_names);
5378 vr_phi_edge_counts = XCNEWVEC (int, num_ssa_names);
5382 gimple_stmt_iterator si;
5384 for (si = gsi_start_phis (bb); !gsi_end_p (si); gsi_next (&si))
5386 gimple phi = gsi_stmt (si);
5387 if (!stmt_interesting_for_vrp (phi))
5389 tree lhs = PHI_RESULT (phi);
5390 set_value_range_to_varying (get_value_range (lhs));
5391 prop_set_simulate_again (phi, false);
5394 prop_set_simulate_again (phi, true);
5397 for (si = gsi_start_bb (bb); !gsi_end_p (si); gsi_next (&si))
5399 gimple stmt = gsi_stmt (si);
5401 /* If the statement is a control insn, then we do not
5402 want to avoid simulating the statement once. Failure
5403 to do so means that those edges will never get added. */
5404 if (stmt_ends_bb_p (stmt))
5405 prop_set_simulate_again (stmt, true);
5406 else if (!stmt_interesting_for_vrp (stmt))
5410 FOR_EACH_SSA_TREE_OPERAND (def, stmt, i, SSA_OP_DEF)
5411 set_value_range_to_varying (get_value_range (def));
5412 prop_set_simulate_again (stmt, false);
5415 prop_set_simulate_again (stmt, true);
5421 /* Visit assignment STMT. If it produces an interesting range, record
5422 the SSA name in *OUTPUT_P. */
5424 static enum ssa_prop_result
5425 vrp_visit_assignment_or_call (gimple stmt, tree *output_p)
5429 enum gimple_code code = gimple_code (stmt);
5430 lhs = gimple_get_lhs (stmt);
5432 /* We only keep track of ranges in integral and pointer types. */
5433 if (TREE_CODE (lhs) == SSA_NAME
5434 && ((INTEGRAL_TYPE_P (TREE_TYPE (lhs))
5435 /* It is valid to have NULL MIN/MAX values on a type. See
5436 build_range_type. */
5437 && TYPE_MIN_VALUE (TREE_TYPE (lhs))
5438 && TYPE_MAX_VALUE (TREE_TYPE (lhs)))
5439 || POINTER_TYPE_P (TREE_TYPE (lhs))))
5441 value_range_t new_vr = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
5443 if (code == GIMPLE_CALL)
5444 extract_range_basic (&new_vr, stmt);
5446 extract_range_from_assignment (&new_vr, stmt);
5448 if (update_value_range (lhs, &new_vr))
5452 if (dump_file && (dump_flags & TDF_DETAILS))
5454 fprintf (dump_file, "Found new range for ");
5455 print_generic_expr (dump_file, lhs, 0);
5456 fprintf (dump_file, ": ");
5457 dump_value_range (dump_file, &new_vr);
5458 fprintf (dump_file, "\n\n");
5461 if (new_vr.type == VR_VARYING)
5462 return SSA_PROP_VARYING;
5464 return SSA_PROP_INTERESTING;
5467 return SSA_PROP_NOT_INTERESTING;
5470 /* Every other statement produces no useful ranges. */
5471 FOR_EACH_SSA_TREE_OPERAND (def, stmt, iter, SSA_OP_DEF)
5472 set_value_range_to_varying (get_value_range (def));
5474 return SSA_PROP_VARYING;
5477 /* Helper that gets the value range of the SSA_NAME with version I
5478 or a symbolic range containing the SSA_NAME only if the value range
5479 is varying or undefined. */
5481 static inline value_range_t
5482 get_vr_for_comparison (int i)
5484 value_range_t vr = *(vr_value[i]);
5486 /* If name N_i does not have a valid range, use N_i as its own
5487 range. This allows us to compare against names that may
5488 have N_i in their ranges. */
5489 if (vr.type == VR_VARYING || vr.type == VR_UNDEFINED)
5492 vr.min = ssa_name (i);
5493 vr.max = ssa_name (i);
5499 /* Compare all the value ranges for names equivalent to VAR with VAL
5500 using comparison code COMP. Return the same value returned by
5501 compare_range_with_value, including the setting of
5502 *STRICT_OVERFLOW_P. */
5505 compare_name_with_value (enum tree_code comp, tree var, tree val,
5506 bool *strict_overflow_p)
5512 int used_strict_overflow;
5514 value_range_t equiv_vr;
5516 /* Get the set of equivalences for VAR. */
5517 e = get_value_range (var)->equiv;
5519 /* Start at -1. Set it to 0 if we do a comparison without relying
5520 on overflow, or 1 if all comparisons rely on overflow. */
5521 used_strict_overflow = -1;
5523 /* Compare vars' value range with val. */
5524 equiv_vr = get_vr_for_comparison (SSA_NAME_VERSION (var));
5526 retval = compare_range_with_value (comp, &equiv_vr, val, &sop);
5528 used_strict_overflow = sop ? 1 : 0;
5530 /* If the equiv set is empty we have done all work we need to do. */
5534 && used_strict_overflow > 0)
5535 *strict_overflow_p = true;
5539 EXECUTE_IF_SET_IN_BITMAP (e, 0, i, bi)
5541 equiv_vr = get_vr_for_comparison (i);
5543 t = compare_range_with_value (comp, &equiv_vr, val, &sop);
5546 /* If we get different answers from different members
5547 of the equivalence set this check must be in a dead
5548 code region. Folding it to a trap representation
5549 would be correct here. For now just return don't-know. */
5559 used_strict_overflow = 0;
5560 else if (used_strict_overflow < 0)
5561 used_strict_overflow = 1;
5566 && used_strict_overflow > 0)
5567 *strict_overflow_p = true;
5573 /* Given a comparison code COMP and names N1 and N2, compare all the
5574 ranges equivalent to N1 against all the ranges equivalent to N2
5575 to determine the value of N1 COMP N2. Return the same value
5576 returned by compare_ranges. Set *STRICT_OVERFLOW_P to indicate
5577 whether we relied on an overflow infinity in the comparison. */
5581 compare_names (enum tree_code comp, tree n1, tree n2,
5582 bool *strict_overflow_p)
5586 bitmap_iterator bi1, bi2;
5588 int used_strict_overflow;
5589 static bitmap_obstack *s_obstack = NULL;
5590 static bitmap s_e1 = NULL, s_e2 = NULL;
5592 /* Compare the ranges of every name equivalent to N1 against the
5593 ranges of every name equivalent to N2. */
5594 e1 = get_value_range (n1)->equiv;
5595 e2 = get_value_range (n2)->equiv;
5597 /* Use the fake bitmaps if e1 or e2 are not available. */
5598 if (s_obstack == NULL)
5600 s_obstack = XNEW (bitmap_obstack);
5601 bitmap_obstack_initialize (s_obstack);
5602 s_e1 = BITMAP_ALLOC (s_obstack);
5603 s_e2 = BITMAP_ALLOC (s_obstack);
5610 /* Add N1 and N2 to their own set of equivalences to avoid
5611 duplicating the body of the loop just to check N1 and N2
5613 bitmap_set_bit (e1, SSA_NAME_VERSION (n1));
5614 bitmap_set_bit (e2, SSA_NAME_VERSION (n2));
5616 /* If the equivalence sets have a common intersection, then the two
5617 names can be compared without checking their ranges. */
5618 if (bitmap_intersect_p (e1, e2))
5620 bitmap_clear_bit (e1, SSA_NAME_VERSION (n1));
5621 bitmap_clear_bit (e2, SSA_NAME_VERSION (n2));
5623 return (comp == EQ_EXPR || comp == GE_EXPR || comp == LE_EXPR)
5625 : boolean_false_node;
5628 /* Start at -1. Set it to 0 if we do a comparison without relying
5629 on overflow, or 1 if all comparisons rely on overflow. */
5630 used_strict_overflow = -1;
5632 /* Otherwise, compare all the equivalent ranges. First, add N1 and
5633 N2 to their own set of equivalences to avoid duplicating the body
5634 of the loop just to check N1 and N2 ranges. */
5635 EXECUTE_IF_SET_IN_BITMAP (e1, 0, i1, bi1)
5637 value_range_t vr1 = get_vr_for_comparison (i1);
5639 t = retval = NULL_TREE;
5640 EXECUTE_IF_SET_IN_BITMAP (e2, 0, i2, bi2)
5644 value_range_t vr2 = get_vr_for_comparison (i2);
5646 t = compare_ranges (comp, &vr1, &vr2, &sop);
5649 /* If we get different answers from different members
5650 of the equivalence set this check must be in a dead
5651 code region. Folding it to a trap representation
5652 would be correct here. For now just return don't-know. */
5656 bitmap_clear_bit (e1, SSA_NAME_VERSION (n1));
5657 bitmap_clear_bit (e2, SSA_NAME_VERSION (n2));
5663 used_strict_overflow = 0;
5664 else if (used_strict_overflow < 0)
5665 used_strict_overflow = 1;
5671 bitmap_clear_bit (e1, SSA_NAME_VERSION (n1));
5672 bitmap_clear_bit (e2, SSA_NAME_VERSION (n2));
5673 if (used_strict_overflow > 0)
5674 *strict_overflow_p = true;
5679 /* None of the equivalent ranges are useful in computing this
5681 bitmap_clear_bit (e1, SSA_NAME_VERSION (n1));
5682 bitmap_clear_bit (e2, SSA_NAME_VERSION (n2));
5686 /* Helper function for vrp_evaluate_conditional_warnv. */
5689 vrp_evaluate_conditional_warnv_with_ops_using_ranges (enum tree_code code,
5691 bool * strict_overflow_p)
5693 value_range_t *vr0, *vr1;
5695 vr0 = (TREE_CODE (op0) == SSA_NAME) ? get_value_range (op0) : NULL;
5696 vr1 = (TREE_CODE (op1) == SSA_NAME) ? get_value_range (op1) : NULL;
5699 return compare_ranges (code, vr0, vr1, strict_overflow_p);
5700 else if (vr0 && vr1 == NULL)
5701 return compare_range_with_value (code, vr0, op1, strict_overflow_p);
5702 else if (vr0 == NULL && vr1)
5703 return (compare_range_with_value
5704 (swap_tree_comparison (code), vr1, op0, strict_overflow_p));
5708 /* Helper function for vrp_evaluate_conditional_warnv. */
5711 vrp_evaluate_conditional_warnv_with_ops (enum tree_code code, tree op0,
5712 tree op1, bool use_equiv_p,
5713 bool *strict_overflow_p, bool *only_ranges)
5717 *only_ranges = true;
5719 /* We only deal with integral and pointer types. */
5720 if (!INTEGRAL_TYPE_P (TREE_TYPE (op0))
5721 && !POINTER_TYPE_P (TREE_TYPE (op0)))
5727 && (ret = vrp_evaluate_conditional_warnv_with_ops_using_ranges
5728 (code, op0, op1, strict_overflow_p)))
5730 *only_ranges = false;
5731 if (TREE_CODE (op0) == SSA_NAME && TREE_CODE (op1) == SSA_NAME)
5732 return compare_names (code, op0, op1, strict_overflow_p);
5733 else if (TREE_CODE (op0) == SSA_NAME)
5734 return compare_name_with_value (code, op0, op1, strict_overflow_p);
5735 else if (TREE_CODE (op1) == SSA_NAME)
5736 return (compare_name_with_value
5737 (swap_tree_comparison (code), op1, op0, strict_overflow_p));
5740 return vrp_evaluate_conditional_warnv_with_ops_using_ranges (code, op0, op1,
5745 /* Given (CODE OP0 OP1) within STMT, try to simplify it based on value range
5746 information. Return NULL if the conditional can not be evaluated.
5747 The ranges of all the names equivalent with the operands in COND
5748 will be used when trying to compute the value. If the result is
5749 based on undefined signed overflow, issue a warning if
5753 vrp_evaluate_conditional (enum tree_code code, tree op0, tree op1, gimple stmt)
5759 /* Some passes and foldings leak constants with overflow flag set
5760 into the IL. Avoid doing wrong things with these and bail out. */
5761 if ((TREE_CODE (op0) == INTEGER_CST
5762 && TREE_OVERFLOW (op0))
5763 || (TREE_CODE (op1) == INTEGER_CST
5764 && TREE_OVERFLOW (op1)))
5768 ret = vrp_evaluate_conditional_warnv_with_ops (code, op0, op1, true, &sop,
5773 enum warn_strict_overflow_code wc;
5774 const char* warnmsg;
5776 if (is_gimple_min_invariant (ret))
5778 wc = WARN_STRICT_OVERFLOW_CONDITIONAL;
5779 warnmsg = G_("assuming signed overflow does not occur when "
5780 "simplifying conditional to constant");
5784 wc = WARN_STRICT_OVERFLOW_COMPARISON;
5785 warnmsg = G_("assuming signed overflow does not occur when "
5786 "simplifying conditional");
5789 if (issue_strict_overflow_warning (wc))
5791 location_t location;
5793 if (!gimple_has_location (stmt))
5794 location = input_location;
5796 location = gimple_location (stmt);
5797 warning_at (location, OPT_Wstrict_overflow, "%s", warnmsg);
5801 if (warn_type_limits
5802 && ret && only_ranges
5803 && TREE_CODE_CLASS (code) == tcc_comparison
5804 && TREE_CODE (op0) == SSA_NAME)
5806 /* If the comparison is being folded and the operand on the LHS
5807 is being compared against a constant value that is outside of
5808 the natural range of OP0's type, then the predicate will
5809 always fold regardless of the value of OP0. If -Wtype-limits
5810 was specified, emit a warning. */
5811 tree type = TREE_TYPE (op0);
5812 value_range_t *vr0 = get_value_range (op0);
5814 if (vr0->type != VR_VARYING
5815 && INTEGRAL_TYPE_P (type)
5816 && vrp_val_is_min (vr0->min)
5817 && vrp_val_is_max (vr0->max)
5818 && is_gimple_min_invariant (op1))
5820 location_t location;
5822 if (!gimple_has_location (stmt))
5823 location = input_location;
5825 location = gimple_location (stmt);
5827 warning_at (location, OPT_Wtype_limits,
5829 ? G_("comparison always false "
5830 "due to limited range of data type")
5831 : G_("comparison always true "
5832 "due to limited range of data type"));
5840 /* Visit conditional statement STMT. If we can determine which edge
5841 will be taken out of STMT's basic block, record it in
5842 *TAKEN_EDGE_P and return SSA_PROP_INTERESTING. Otherwise, return
5843 SSA_PROP_VARYING. */
5845 static enum ssa_prop_result
5846 vrp_visit_cond_stmt (gimple stmt, edge *taken_edge_p)
5851 *taken_edge_p = NULL;
5853 if (dump_file && (dump_flags & TDF_DETAILS))
5858 fprintf (dump_file, "\nVisiting conditional with predicate: ");
5859 print_gimple_stmt (dump_file, stmt, 0, 0);
5860 fprintf (dump_file, "\nWith known ranges\n");
5862 FOR_EACH_SSA_TREE_OPERAND (use, stmt, i, SSA_OP_USE)
5864 fprintf (dump_file, "\t");
5865 print_generic_expr (dump_file, use, 0);
5866 fprintf (dump_file, ": ");
5867 dump_value_range (dump_file, vr_value[SSA_NAME_VERSION (use)]);
5870 fprintf (dump_file, "\n");
5873 /* Compute the value of the predicate COND by checking the known
5874 ranges of each of its operands.
5876 Note that we cannot evaluate all the equivalent ranges here
5877 because those ranges may not yet be final and with the current
5878 propagation strategy, we cannot determine when the value ranges
5879 of the names in the equivalence set have changed.
5881 For instance, given the following code fragment
5885 i_14 = ASSERT_EXPR <i_5, i_5 != 0>
5889 Assume that on the first visit to i_14, i_5 has the temporary
5890 range [8, 8] because the second argument to the PHI function is
5891 not yet executable. We derive the range ~[0, 0] for i_14 and the
5892 equivalence set { i_5 }. So, when we visit 'if (i_14 == 1)' for
5893 the first time, since i_14 is equivalent to the range [8, 8], we
5894 determine that the predicate is always false.
5896 On the next round of propagation, i_13 is determined to be
5897 VARYING, which causes i_5 to drop down to VARYING. So, another
5898 visit to i_14 is scheduled. In this second visit, we compute the
5899 exact same range and equivalence set for i_14, namely ~[0, 0] and
5900 { i_5 }. But we did not have the previous range for i_5
5901 registered, so vrp_visit_assignment thinks that the range for
5902 i_14 has not changed. Therefore, the predicate 'if (i_14 == 1)'
5903 is not visited again, which stops propagation from visiting
5904 statements in the THEN clause of that if().
5906 To properly fix this we would need to keep the previous range
5907 value for the names in the equivalence set. This way we would've
5908 discovered that from one visit to the other i_5 changed from
5909 range [8, 8] to VR_VARYING.
5911 However, fixing this apparent limitation may not be worth the
5912 additional checking. Testing on several code bases (GCC, DLV,
5913 MICO, TRAMP3D and SPEC2000) showed that doing this results in
5914 4 more predicates folded in SPEC. */
5917 val = vrp_evaluate_conditional_warnv_with_ops (gimple_cond_code (stmt),
5918 gimple_cond_lhs (stmt),
5919 gimple_cond_rhs (stmt),
5924 *taken_edge_p = find_taken_edge (gimple_bb (stmt), val);
5927 if (dump_file && (dump_flags & TDF_DETAILS))
5929 "\nIgnoring predicate evaluation because "
5930 "it assumes that signed overflow is undefined");
5935 if (dump_file && (dump_flags & TDF_DETAILS))
5937 fprintf (dump_file, "\nPredicate evaluates to: ");
5938 if (val == NULL_TREE)
5939 fprintf (dump_file, "DON'T KNOW\n");
5941 print_generic_stmt (dump_file, val, 0);
5944 return (*taken_edge_p) ? SSA_PROP_INTERESTING : SSA_PROP_VARYING;
5947 /* Searches the case label vector VEC for the index *IDX of the CASE_LABEL
5948 that includes the value VAL. The search is restricted to the range
5949 [START_IDX, n - 1] where n is the size of VEC.
5951 If there is a CASE_LABEL for VAL, its index is placed in IDX and true is
5954 If there is no CASE_LABEL for VAL and there is one that is larger than VAL,
5955 it is placed in IDX and false is returned.
5957 If VAL is larger than any CASE_LABEL, n is placed on IDX and false is
5961 find_case_label_index (gimple stmt, size_t start_idx, tree val, size_t *idx)
5963 size_t n = gimple_switch_num_labels (stmt);
5966 /* Find case label for minimum of the value range or the next one.
5967 At each iteration we are searching in [low, high - 1]. */
5969 for (low = start_idx, high = n; high != low; )
5973 /* Note that i != high, so we never ask for n. */
5974 size_t i = (high + low) / 2;
5975 t = gimple_switch_label (stmt, i);
5977 /* Cache the result of comparing CASE_LOW and val. */
5978 cmp = tree_int_cst_compare (CASE_LOW (t), val);
5982 /* Ranges cannot be empty. */
5991 if (CASE_HIGH (t) != NULL
5992 && tree_int_cst_compare (CASE_HIGH (t), val) >= 0)
6004 /* Searches the case label vector VEC for the range of CASE_LABELs that is used
6005 for values between MIN and MAX. The first index is placed in MIN_IDX. The
6006 last index is placed in MAX_IDX. If the range of CASE_LABELs is empty
6007 then MAX_IDX < MIN_IDX.
6008 Returns true if the default label is not needed. */
6011 find_case_label_range (gimple stmt, tree min, tree max, size_t *min_idx,
6015 bool min_take_default = !find_case_label_index (stmt, 1, min, &i);
6016 bool max_take_default = !find_case_label_index (stmt, i, max, &j);
6020 && max_take_default)
6022 /* Only the default case label reached.
6023 Return an empty range. */
6030 bool take_default = min_take_default || max_take_default;
6034 if (max_take_default)
6037 /* If the case label range is continuous, we do not need
6038 the default case label. Verify that. */
6039 high = CASE_LOW (gimple_switch_label (stmt, i));
6040 if (CASE_HIGH (gimple_switch_label (stmt, i)))
6041 high = CASE_HIGH (gimple_switch_label (stmt, i));
6042 for (k = i + 1; k <= j; ++k)
6044 low = CASE_LOW (gimple_switch_label (stmt, k));
6045 if (!integer_onep (int_const_binop (MINUS_EXPR, low, high, 0)))
6047 take_default = true;
6051 if (CASE_HIGH (gimple_switch_label (stmt, k)))
6052 high = CASE_HIGH (gimple_switch_label (stmt, k));
6057 return !take_default;
6061 /* Visit switch statement STMT. If we can determine which edge
6062 will be taken out of STMT's basic block, record it in
6063 *TAKEN_EDGE_P and return SSA_PROP_INTERESTING. Otherwise, return
6064 SSA_PROP_VARYING. */
6066 static enum ssa_prop_result
6067 vrp_visit_switch_stmt (gimple stmt, edge *taken_edge_p)
6071 size_t i = 0, j = 0;
6074 *taken_edge_p = NULL;
6075 op = gimple_switch_index (stmt);
6076 if (TREE_CODE (op) != SSA_NAME)
6077 return SSA_PROP_VARYING;
6079 vr = get_value_range (op);
6080 if (dump_file && (dump_flags & TDF_DETAILS))
6082 fprintf (dump_file, "\nVisiting switch expression with operand ");
6083 print_generic_expr (dump_file, op, 0);
6084 fprintf (dump_file, " with known range ");
6085 dump_value_range (dump_file, vr);
6086 fprintf (dump_file, "\n");
6089 if (vr->type != VR_RANGE
6090 || symbolic_range_p (vr))
6091 return SSA_PROP_VARYING;
6093 /* Find the single edge that is taken from the switch expression. */
6094 take_default = !find_case_label_range (stmt, vr->min, vr->max, &i, &j);
6096 /* Check if the range spans no CASE_LABEL. If so, we only reach the default
6100 gcc_assert (take_default);
6101 val = gimple_switch_default_label (stmt);
6105 /* Check if labels with index i to j and maybe the default label
6106 are all reaching the same label. */
6108 val = gimple_switch_label (stmt, i);
6110 && CASE_LABEL (gimple_switch_default_label (stmt))
6111 != CASE_LABEL (val))
6113 if (dump_file && (dump_flags & TDF_DETAILS))
6114 fprintf (dump_file, " not a single destination for this "
6116 return SSA_PROP_VARYING;
6118 for (++i; i <= j; ++i)
6120 if (CASE_LABEL (gimple_switch_label (stmt, i)) != CASE_LABEL (val))
6122 if (dump_file && (dump_flags & TDF_DETAILS))
6123 fprintf (dump_file, " not a single destination for this "
6125 return SSA_PROP_VARYING;
6130 *taken_edge_p = find_edge (gimple_bb (stmt),
6131 label_to_block (CASE_LABEL (val)));
6133 if (dump_file && (dump_flags & TDF_DETAILS))
6135 fprintf (dump_file, " will take edge to ");
6136 print_generic_stmt (dump_file, CASE_LABEL (val), 0);
6139 return SSA_PROP_INTERESTING;
6143 /* Evaluate statement STMT. If the statement produces a useful range,
6144 return SSA_PROP_INTERESTING and record the SSA name with the
6145 interesting range into *OUTPUT_P.
6147 If STMT is a conditional branch and we can determine its truth
6148 value, the taken edge is recorded in *TAKEN_EDGE_P.
6150 If STMT produces a varying value, return SSA_PROP_VARYING. */
6152 static enum ssa_prop_result
6153 vrp_visit_stmt (gimple stmt, edge *taken_edge_p, tree *output_p)
6158 if (dump_file && (dump_flags & TDF_DETAILS))
6160 fprintf (dump_file, "\nVisiting statement:\n");
6161 print_gimple_stmt (dump_file, stmt, 0, dump_flags);
6162 fprintf (dump_file, "\n");
6165 if (!stmt_interesting_for_vrp (stmt))
6166 gcc_assert (stmt_ends_bb_p (stmt));
6167 else if (is_gimple_assign (stmt) || is_gimple_call (stmt))
6169 /* In general, assignments with virtual operands are not useful
6170 for deriving ranges, with the obvious exception of calls to
6171 builtin functions. */
6173 if ((is_gimple_call (stmt)
6174 && gimple_call_fndecl (stmt) != NULL_TREE
6175 && DECL_IS_BUILTIN (gimple_call_fndecl (stmt)))
6176 || !gimple_vuse (stmt))
6177 return vrp_visit_assignment_or_call (stmt, output_p);
6179 else if (gimple_code (stmt) == GIMPLE_COND)
6180 return vrp_visit_cond_stmt (stmt, taken_edge_p);
6181 else if (gimple_code (stmt) == GIMPLE_SWITCH)
6182 return vrp_visit_switch_stmt (stmt, taken_edge_p);
6184 /* All other statements produce nothing of interest for VRP, so mark
6185 their outputs varying and prevent further simulation. */
6186 FOR_EACH_SSA_TREE_OPERAND (def, stmt, iter, SSA_OP_DEF)
6187 set_value_range_to_varying (get_value_range (def));
6189 return SSA_PROP_VARYING;
6193 /* Meet operation for value ranges. Given two value ranges VR0 and
6194 VR1, store in VR0 a range that contains both VR0 and VR1. This
6195 may not be the smallest possible such range. */
6198 vrp_meet (value_range_t *vr0, value_range_t *vr1)
6200 if (vr0->type == VR_UNDEFINED)
6202 copy_value_range (vr0, vr1);
6206 if (vr1->type == VR_UNDEFINED)
6208 /* Nothing to do. VR0 already has the resulting range. */
6212 if (vr0->type == VR_VARYING)
6214 /* Nothing to do. VR0 already has the resulting range. */
6218 if (vr1->type == VR_VARYING)
6220 set_value_range_to_varying (vr0);
6224 if (vr0->type == VR_RANGE && vr1->type == VR_RANGE)
6229 /* Compute the convex hull of the ranges. The lower limit of
6230 the new range is the minimum of the two ranges. If they
6231 cannot be compared, then give up. */
6232 cmp = compare_values (vr0->min, vr1->min);
6233 if (cmp == 0 || cmp == 1)
6240 /* Similarly, the upper limit of the new range is the maximum
6241 of the two ranges. If they cannot be compared, then
6243 cmp = compare_values (vr0->max, vr1->max);
6244 if (cmp == 0 || cmp == -1)
6251 /* Check for useless ranges. */
6252 if (INTEGRAL_TYPE_P (TREE_TYPE (min))
6253 && ((vrp_val_is_min (min) || is_overflow_infinity (min))
6254 && (vrp_val_is_max (max) || is_overflow_infinity (max))))
6257 /* The resulting set of equivalences is the intersection of
6259 if (vr0->equiv && vr1->equiv && vr0->equiv != vr1->equiv)
6260 bitmap_and_into (vr0->equiv, vr1->equiv);
6261 else if (vr0->equiv && !vr1->equiv)
6262 bitmap_clear (vr0->equiv);
6264 set_value_range (vr0, vr0->type, min, max, vr0->equiv);
6266 else if (vr0->type == VR_ANTI_RANGE && vr1->type == VR_ANTI_RANGE)
6268 /* Two anti-ranges meet only if their complements intersect.
6269 Only handle the case of identical ranges. */
6270 if (compare_values (vr0->min, vr1->min) == 0
6271 && compare_values (vr0->max, vr1->max) == 0
6272 && compare_values (vr0->min, vr0->max) == 0)
6274 /* The resulting set of equivalences is the intersection of
6276 if (vr0->equiv && vr1->equiv && vr0->equiv != vr1->equiv)
6277 bitmap_and_into (vr0->equiv, vr1->equiv);
6278 else if (vr0->equiv && !vr1->equiv)
6279 bitmap_clear (vr0->equiv);
6284 else if (vr0->type == VR_ANTI_RANGE || vr1->type == VR_ANTI_RANGE)
6286 /* For a numeric range [VAL1, VAL2] and an anti-range ~[VAL3, VAL4],
6287 only handle the case where the ranges have an empty intersection.
6288 The result of the meet operation is the anti-range. */
6289 if (!symbolic_range_p (vr0)
6290 && !symbolic_range_p (vr1)
6291 && !value_ranges_intersect_p (vr0, vr1))
6293 /* Copy most of VR1 into VR0. Don't copy VR1's equivalence
6294 set. We need to compute the intersection of the two
6295 equivalence sets. */
6296 if (vr1->type == VR_ANTI_RANGE)
6297 set_value_range (vr0, vr1->type, vr1->min, vr1->max, vr0->equiv);
6299 /* The resulting set of equivalences is the intersection of
6301 if (vr0->equiv && vr1->equiv && vr0->equiv != vr1->equiv)
6302 bitmap_and_into (vr0->equiv, vr1->equiv);
6303 else if (vr0->equiv && !vr1->equiv)
6304 bitmap_clear (vr0->equiv);
6315 /* Failed to find an efficient meet. Before giving up and setting
6316 the result to VARYING, see if we can at least derive a useful
6317 anti-range. FIXME, all this nonsense about distinguishing
6318 anti-ranges from ranges is necessary because of the odd
6319 semantics of range_includes_zero_p and friends. */
6320 if (!symbolic_range_p (vr0)
6321 && ((vr0->type == VR_RANGE && !range_includes_zero_p (vr0))
6322 || (vr0->type == VR_ANTI_RANGE && range_includes_zero_p (vr0)))
6323 && !symbolic_range_p (vr1)
6324 && ((vr1->type == VR_RANGE && !range_includes_zero_p (vr1))
6325 || (vr1->type == VR_ANTI_RANGE && range_includes_zero_p (vr1))))
6327 set_value_range_to_nonnull (vr0, TREE_TYPE (vr0->min));
6329 /* Since this meet operation did not result from the meeting of
6330 two equivalent names, VR0 cannot have any equivalences. */
6332 bitmap_clear (vr0->equiv);
6335 set_value_range_to_varying (vr0);
6339 /* Visit all arguments for PHI node PHI that flow through executable
6340 edges. If a valid value range can be derived from all the incoming
6341 value ranges, set a new range for the LHS of PHI. */
6343 static enum ssa_prop_result
6344 vrp_visit_phi_node (gimple phi)
6347 tree lhs = PHI_RESULT (phi);
6348 value_range_t *lhs_vr = get_value_range (lhs);
6349 value_range_t vr_result = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
6350 int edges, old_edges;
6353 copy_value_range (&vr_result, lhs_vr);
6355 if (dump_file && (dump_flags & TDF_DETAILS))
6357 fprintf (dump_file, "\nVisiting PHI node: ");
6358 print_gimple_stmt (dump_file, phi, 0, dump_flags);
6362 for (i = 0; i < gimple_phi_num_args (phi); i++)
6364 edge e = gimple_phi_arg_edge (phi, i);
6366 if (dump_file && (dump_flags & TDF_DETAILS))
6369 "\n Argument #%d (%d -> %d %sexecutable)\n",
6370 (int) i, e->src->index, e->dest->index,
6371 (e->flags & EDGE_EXECUTABLE) ? "" : "not ");
6374 if (e->flags & EDGE_EXECUTABLE)
6376 tree arg = PHI_ARG_DEF (phi, i);
6377 value_range_t vr_arg;
6381 if (TREE_CODE (arg) == SSA_NAME)
6383 vr_arg = *(get_value_range (arg));
6387 if (is_overflow_infinity (arg))
6389 arg = copy_node (arg);
6390 TREE_OVERFLOW (arg) = 0;
6393 vr_arg.type = VR_RANGE;
6396 vr_arg.equiv = NULL;
6399 if (dump_file && (dump_flags & TDF_DETAILS))
6401 fprintf (dump_file, "\t");
6402 print_generic_expr (dump_file, arg, dump_flags);
6403 fprintf (dump_file, "\n\tValue: ");
6404 dump_value_range (dump_file, &vr_arg);
6405 fprintf (dump_file, "\n");
6408 vrp_meet (&vr_result, &vr_arg);
6410 if (vr_result.type == VR_VARYING)
6415 /* If this is a loop PHI node SCEV may known more about its
6418 && (l = loop_containing_stmt (phi))
6419 && l->header == gimple_bb (phi))
6420 adjust_range_with_scev (&vr_result, l, phi, lhs);
6422 if (vr_result.type == VR_VARYING)
6425 old_edges = vr_phi_edge_counts[SSA_NAME_VERSION (lhs)];
6426 vr_phi_edge_counts[SSA_NAME_VERSION (lhs)] = edges;
6428 /* To prevent infinite iterations in the algorithm, derive ranges
6429 when the new value is slightly bigger or smaller than the
6430 previous one. We don't do this if we have seen a new executable
6431 edge; this helps us avoid an overflow infinity for conditionals
6432 which are not in a loop. */
6433 if (lhs_vr->type == VR_RANGE && vr_result.type == VR_RANGE
6434 && edges <= old_edges)
6436 if (!POINTER_TYPE_P (TREE_TYPE (lhs)))
6438 int cmp_min = compare_values (lhs_vr->min, vr_result.min);
6439 int cmp_max = compare_values (lhs_vr->max, vr_result.max);
6441 /* If the new minimum is smaller or larger than the previous
6442 one, go all the way to -INF. In the first case, to avoid
6443 iterating millions of times to reach -INF, and in the
6444 other case to avoid infinite bouncing between different
6446 if (cmp_min > 0 || cmp_min < 0)
6448 /* If we will end up with a (-INF, +INF) range, set it to
6449 VARYING. Same if the previous max value was invalid for
6450 the type and we'd end up with vr_result.min > vr_result.max. */
6451 if (vrp_val_is_max (vr_result.max)
6452 || compare_values (TYPE_MIN_VALUE (TREE_TYPE (vr_result.min)),
6456 if (!needs_overflow_infinity (TREE_TYPE (vr_result.min))
6457 || !vrp_var_may_overflow (lhs, phi))
6458 vr_result.min = TYPE_MIN_VALUE (TREE_TYPE (vr_result.min));
6459 else if (supports_overflow_infinity (TREE_TYPE (vr_result.min)))
6461 negative_overflow_infinity (TREE_TYPE (vr_result.min));
6466 /* Similarly, if the new maximum is smaller or larger than
6467 the previous one, go all the way to +INF. */
6468 if (cmp_max < 0 || cmp_max > 0)
6470 /* If we will end up with a (-INF, +INF) range, set it to
6471 VARYING. Same if the previous min value was invalid for
6472 the type and we'd end up with vr_result.max < vr_result.min. */
6473 if (vrp_val_is_min (vr_result.min)
6474 || compare_values (TYPE_MAX_VALUE (TREE_TYPE (vr_result.max)),
6478 if (!needs_overflow_infinity (TREE_TYPE (vr_result.max))
6479 || !vrp_var_may_overflow (lhs, phi))
6480 vr_result.max = TYPE_MAX_VALUE (TREE_TYPE (vr_result.max));
6481 else if (supports_overflow_infinity (TREE_TYPE (vr_result.max)))
6483 positive_overflow_infinity (TREE_TYPE (vr_result.max));
6490 /* If the new range is different than the previous value, keep
6492 if (update_value_range (lhs, &vr_result))
6494 if (dump_file && (dump_flags & TDF_DETAILS))
6496 fprintf (dump_file, "Found new range for ");
6497 print_generic_expr (dump_file, lhs, 0);
6498 fprintf (dump_file, ": ");
6499 dump_value_range (dump_file, &vr_result);
6500 fprintf (dump_file, "\n\n");
6503 return SSA_PROP_INTERESTING;
6506 /* Nothing changed, don't add outgoing edges. */
6507 return SSA_PROP_NOT_INTERESTING;
6509 /* No match found. Set the LHS to VARYING. */
6511 set_value_range_to_varying (lhs_vr);
6512 return SSA_PROP_VARYING;
6515 /* Simplify boolean operations if the source is known
6516 to be already a boolean. */
6518 simplify_truth_ops_using_ranges (gimple_stmt_iterator *gsi, gimple stmt)
6520 enum tree_code rhs_code = gimple_assign_rhs_code (stmt);
6525 bool need_conversion;
6527 op0 = gimple_assign_rhs1 (stmt);
6528 if (TYPE_PRECISION (TREE_TYPE (op0)) != 1)
6530 if (TREE_CODE (op0) != SSA_NAME)
6532 vr = get_value_range (op0);
6534 val = compare_range_with_value (GE_EXPR, vr, integer_zero_node, &sop);
6535 if (!val || !integer_onep (val))
6538 val = compare_range_with_value (LE_EXPR, vr, integer_one_node, &sop);
6539 if (!val || !integer_onep (val))
6543 if (rhs_code == TRUTH_NOT_EXPR)
6546 op1 = build_int_cst (TREE_TYPE (op0), 1);
6550 op1 = gimple_assign_rhs2 (stmt);
6552 /* Reduce number of cases to handle. */
6553 if (is_gimple_min_invariant (op1))
6555 /* Exclude anything that should have been already folded. */
6556 if (rhs_code != EQ_EXPR
6557 && rhs_code != NE_EXPR
6558 && rhs_code != TRUTH_XOR_EXPR)
6561 if (!integer_zerop (op1)
6562 && !integer_onep (op1)
6563 && !integer_all_onesp (op1))
6566 /* Limit the number of cases we have to consider. */
6567 if (rhs_code == EQ_EXPR)
6570 op1 = fold_unary (TRUTH_NOT_EXPR, TREE_TYPE (op1), op1);
6575 /* Punt on A == B as there is no BIT_XNOR_EXPR. */
6576 if (rhs_code == EQ_EXPR)
6579 if (TYPE_PRECISION (TREE_TYPE (op1)) != 1)
6581 vr = get_value_range (op1);
6582 val = compare_range_with_value (GE_EXPR, vr, integer_zero_node, &sop);
6583 if (!val || !integer_onep (val))
6586 val = compare_range_with_value (LE_EXPR, vr, integer_one_node, &sop);
6587 if (!val || !integer_onep (val))
6593 if (sop && issue_strict_overflow_warning (WARN_STRICT_OVERFLOW_MISC))
6595 location_t location;
6597 if (!gimple_has_location (stmt))
6598 location = input_location;
6600 location = gimple_location (stmt);
6602 if (rhs_code == TRUTH_AND_EXPR || rhs_code == TRUTH_OR_EXPR)
6603 warning_at (location, OPT_Wstrict_overflow,
6604 _("assuming signed overflow does not occur when "
6605 "simplifying && or || to & or |"));
6607 warning_at (location, OPT_Wstrict_overflow,
6608 _("assuming signed overflow does not occur when "
6609 "simplifying ==, != or ! to identity or ^"));
6613 !useless_type_conversion_p (TREE_TYPE (gimple_assign_lhs (stmt)),
6616 /* Make sure to not sign-extend -1 as a boolean value. */
6618 && !TYPE_UNSIGNED (TREE_TYPE (op0))
6619 && TYPE_PRECISION (TREE_TYPE (op0)) == 1)
6624 case TRUTH_AND_EXPR:
6625 rhs_code = BIT_AND_EXPR;
6628 rhs_code = BIT_IOR_EXPR;
6630 case TRUTH_XOR_EXPR:
6632 if (integer_zerop (op1))
6634 gimple_assign_set_rhs_with_ops (gsi,
6635 need_conversion ? NOP_EXPR : SSA_NAME,
6637 update_stmt (gsi_stmt (*gsi));
6641 rhs_code = BIT_XOR_EXPR;
6647 if (need_conversion)
6650 gimple_assign_set_rhs_with_ops (gsi, rhs_code, op0, op1);
6651 update_stmt (gsi_stmt (*gsi));
6655 /* Simplify a division or modulo operator to a right shift or
6656 bitwise and if the first operand is unsigned or is greater
6657 than zero and the second operand is an exact power of two. */
6660 simplify_div_or_mod_using_ranges (gimple stmt)
6662 enum tree_code rhs_code = gimple_assign_rhs_code (stmt);
6664 tree op0 = gimple_assign_rhs1 (stmt);
6665 tree op1 = gimple_assign_rhs2 (stmt);
6666 value_range_t *vr = get_value_range (gimple_assign_rhs1 (stmt));
6668 if (TYPE_UNSIGNED (TREE_TYPE (op0)))
6670 val = integer_one_node;
6676 val = compare_range_with_value (GE_EXPR, vr, integer_zero_node, &sop);
6680 && integer_onep (val)
6681 && issue_strict_overflow_warning (WARN_STRICT_OVERFLOW_MISC))
6683 location_t location;
6685 if (!gimple_has_location (stmt))
6686 location = input_location;
6688 location = gimple_location (stmt);
6689 warning_at (location, OPT_Wstrict_overflow,
6690 "assuming signed overflow does not occur when "
6691 "simplifying %</%> or %<%%%> to %<>>%> or %<&%>");
6695 if (val && integer_onep (val))
6699 if (rhs_code == TRUNC_DIV_EXPR)
6701 t = build_int_cst (NULL_TREE, tree_log2 (op1));
6702 gimple_assign_set_rhs_code (stmt, RSHIFT_EXPR);
6703 gimple_assign_set_rhs1 (stmt, op0);
6704 gimple_assign_set_rhs2 (stmt, t);
6708 t = build_int_cst (TREE_TYPE (op1), 1);
6709 t = int_const_binop (MINUS_EXPR, op1, t, 0);
6710 t = fold_convert (TREE_TYPE (op0), t);
6712 gimple_assign_set_rhs_code (stmt, BIT_AND_EXPR);
6713 gimple_assign_set_rhs1 (stmt, op0);
6714 gimple_assign_set_rhs2 (stmt, t);
6724 /* If the operand to an ABS_EXPR is >= 0, then eliminate the
6725 ABS_EXPR. If the operand is <= 0, then simplify the
6726 ABS_EXPR into a NEGATE_EXPR. */
6729 simplify_abs_using_ranges (gimple stmt)
6732 tree op = gimple_assign_rhs1 (stmt);
6733 tree type = TREE_TYPE (op);
6734 value_range_t *vr = get_value_range (op);
6736 if (TYPE_UNSIGNED (type))
6738 val = integer_zero_node;
6744 val = compare_range_with_value (LE_EXPR, vr, integer_zero_node, &sop);
6748 val = compare_range_with_value (GE_EXPR, vr, integer_zero_node,
6753 if (integer_zerop (val))
6754 val = integer_one_node;
6755 else if (integer_onep (val))
6756 val = integer_zero_node;
6761 && (integer_onep (val) || integer_zerop (val)))
6763 if (sop && issue_strict_overflow_warning (WARN_STRICT_OVERFLOW_MISC))
6765 location_t location;
6767 if (!gimple_has_location (stmt))
6768 location = input_location;
6770 location = gimple_location (stmt);
6771 warning_at (location, OPT_Wstrict_overflow,
6772 "assuming signed overflow does not occur when "
6773 "simplifying %<abs (X)%> to %<X%> or %<-X%>");
6776 gimple_assign_set_rhs1 (stmt, op);
6777 if (integer_onep (val))
6778 gimple_assign_set_rhs_code (stmt, NEGATE_EXPR);
6780 gimple_assign_set_rhs_code (stmt, SSA_NAME);
6789 /* We are comparing trees OP0 and OP1 using COND_CODE. OP0 has
6790 a known value range VR.
6792 If there is one and only one value which will satisfy the
6793 conditional, then return that value. Else return NULL. */
6796 test_for_singularity (enum tree_code cond_code, tree op0,
6797 tree op1, value_range_t *vr)
6802 /* Extract minimum/maximum values which satisfy the
6803 the conditional as it was written. */
6804 if (cond_code == LE_EXPR || cond_code == LT_EXPR)
6806 /* This should not be negative infinity; there is no overflow
6808 min = TYPE_MIN_VALUE (TREE_TYPE (op0));
6811 if (cond_code == LT_EXPR && !is_overflow_infinity (max))
6813 tree one = build_int_cst (TREE_TYPE (op0), 1);
6814 max = fold_build2 (MINUS_EXPR, TREE_TYPE (op0), max, one);
6816 TREE_NO_WARNING (max) = 1;
6819 else if (cond_code == GE_EXPR || cond_code == GT_EXPR)
6821 /* This should not be positive infinity; there is no overflow
6823 max = TYPE_MAX_VALUE (TREE_TYPE (op0));
6826 if (cond_code == GT_EXPR && !is_overflow_infinity (min))
6828 tree one = build_int_cst (TREE_TYPE (op0), 1);
6829 min = fold_build2 (PLUS_EXPR, TREE_TYPE (op0), min, one);
6831 TREE_NO_WARNING (min) = 1;
6835 /* Now refine the minimum and maximum values using any
6836 value range information we have for op0. */
6839 if (compare_values (vr->min, min) == 1)
6841 if (compare_values (vr->max, max) == -1)
6844 /* If the new min/max values have converged to a single value,
6845 then there is only one value which can satisfy the condition,
6846 return that value. */
6847 if (operand_equal_p (min, max, 0) && is_gimple_min_invariant (min))
6853 /* Simplify a conditional using a relational operator to an equality
6854 test if the range information indicates only one value can satisfy
6855 the original conditional. */
6858 simplify_cond_using_ranges (gimple stmt)
6860 tree op0 = gimple_cond_lhs (stmt);
6861 tree op1 = gimple_cond_rhs (stmt);
6862 enum tree_code cond_code = gimple_cond_code (stmt);
6864 if (cond_code != NE_EXPR
6865 && cond_code != EQ_EXPR
6866 && TREE_CODE (op0) == SSA_NAME
6867 && INTEGRAL_TYPE_P (TREE_TYPE (op0))
6868 && is_gimple_min_invariant (op1))
6870 value_range_t *vr = get_value_range (op0);
6872 /* If we have range information for OP0, then we might be
6873 able to simplify this conditional. */
6874 if (vr->type == VR_RANGE)
6876 tree new_tree = test_for_singularity (cond_code, op0, op1, vr);
6882 fprintf (dump_file, "Simplified relational ");
6883 print_gimple_stmt (dump_file, stmt, 0, 0);
6884 fprintf (dump_file, " into ");
6887 gimple_cond_set_code (stmt, EQ_EXPR);
6888 gimple_cond_set_lhs (stmt, op0);
6889 gimple_cond_set_rhs (stmt, new_tree);
6895 print_gimple_stmt (dump_file, stmt, 0, 0);
6896 fprintf (dump_file, "\n");
6902 /* Try again after inverting the condition. We only deal
6903 with integral types here, so no need to worry about
6904 issues with inverting FP comparisons. */
6905 cond_code = invert_tree_comparison (cond_code, false);
6906 new_tree = test_for_singularity (cond_code, op0, op1, vr);
6912 fprintf (dump_file, "Simplified relational ");
6913 print_gimple_stmt (dump_file, stmt, 0, 0);
6914 fprintf (dump_file, " into ");
6917 gimple_cond_set_code (stmt, NE_EXPR);
6918 gimple_cond_set_lhs (stmt, op0);
6919 gimple_cond_set_rhs (stmt, new_tree);
6925 print_gimple_stmt (dump_file, stmt, 0, 0);
6926 fprintf (dump_file, "\n");
6937 /* Simplify a switch statement using the value range of the switch
6941 simplify_switch_using_ranges (gimple stmt)
6943 tree op = gimple_switch_index (stmt);
6948 size_t i = 0, j = 0, n, n2;
6952 if (TREE_CODE (op) == SSA_NAME)
6954 vr = get_value_range (op);
6956 /* We can only handle integer ranges. */
6957 if (vr->type != VR_RANGE
6958 || symbolic_range_p (vr))
6961 /* Find case label for min/max of the value range. */
6962 take_default = !find_case_label_range (stmt, vr->min, vr->max, &i, &j);
6964 else if (TREE_CODE (op) == INTEGER_CST)
6966 take_default = !find_case_label_index (stmt, 1, op, &i);
6980 n = gimple_switch_num_labels (stmt);
6982 /* Bail out if this is just all edges taken. */
6988 /* Build a new vector of taken case labels. */
6989 vec2 = make_tree_vec (j - i + 1 + (int)take_default);
6992 /* Add the default edge, if necessary. */
6994 TREE_VEC_ELT (vec2, n2++) = gimple_switch_default_label (stmt);
6996 for (; i <= j; ++i, ++n2)
6997 TREE_VEC_ELT (vec2, n2) = gimple_switch_label (stmt, i);
6999 /* Mark needed edges. */
7000 for (i = 0; i < n2; ++i)
7002 e = find_edge (gimple_bb (stmt),
7003 label_to_block (CASE_LABEL (TREE_VEC_ELT (vec2, i))));
7004 e->aux = (void *)-1;
7007 /* Queue not needed edges for later removal. */
7008 FOR_EACH_EDGE (e, ei, gimple_bb (stmt)->succs)
7010 if (e->aux == (void *)-1)
7016 if (dump_file && (dump_flags & TDF_DETAILS))
7018 fprintf (dump_file, "removing unreachable case label\n");
7020 VEC_safe_push (edge, heap, to_remove_edges, e);
7021 e->flags &= ~EDGE_EXECUTABLE;
7024 /* And queue an update for the stmt. */
7027 VEC_safe_push (switch_update, heap, to_update_switch_stmts, &su);
7031 /* Simplify STMT using ranges if possible. */
7034 simplify_stmt_using_ranges (gimple_stmt_iterator *gsi)
7036 gimple stmt = gsi_stmt (*gsi);
7037 if (is_gimple_assign (stmt))
7039 enum tree_code rhs_code = gimple_assign_rhs_code (stmt);
7045 case TRUTH_NOT_EXPR:
7046 case TRUTH_AND_EXPR:
7048 case TRUTH_XOR_EXPR:
7049 /* Transform EQ_EXPR, NE_EXPR, TRUTH_NOT_EXPR into BIT_XOR_EXPR
7050 or identity if the RHS is zero or one, and the LHS are known
7051 to be boolean values. Transform all TRUTH_*_EXPR into
7052 BIT_*_EXPR if both arguments are known to be boolean values. */
7053 if (INTEGRAL_TYPE_P (TREE_TYPE (gimple_assign_rhs1 (stmt))))
7054 return simplify_truth_ops_using_ranges (gsi, stmt);
7057 /* Transform TRUNC_DIV_EXPR and TRUNC_MOD_EXPR into RSHIFT_EXPR
7058 and BIT_AND_EXPR respectively if the first operand is greater
7059 than zero and the second operand is an exact power of two. */
7060 case TRUNC_DIV_EXPR:
7061 case TRUNC_MOD_EXPR:
7062 if (INTEGRAL_TYPE_P (TREE_TYPE (gimple_assign_rhs1 (stmt)))
7063 && integer_pow2p (gimple_assign_rhs2 (stmt)))
7064 return simplify_div_or_mod_using_ranges (stmt);
7067 /* Transform ABS (X) into X or -X as appropriate. */
7069 if (TREE_CODE (gimple_assign_rhs1 (stmt)) == SSA_NAME
7070 && INTEGRAL_TYPE_P (TREE_TYPE (gimple_assign_rhs1 (stmt))))
7071 return simplify_abs_using_ranges (stmt);
7078 else if (gimple_code (stmt) == GIMPLE_COND)
7079 return simplify_cond_using_ranges (stmt);
7080 else if (gimple_code (stmt) == GIMPLE_SWITCH)
7081 return simplify_switch_using_ranges (stmt);
7086 /* If the statement pointed by SI has a predicate whose value can be
7087 computed using the value range information computed by VRP, compute
7088 its value and return true. Otherwise, return false. */
7091 fold_predicate_in (gimple_stmt_iterator *si)
7093 bool assignment_p = false;
7095 gimple stmt = gsi_stmt (*si);
7097 if (is_gimple_assign (stmt)
7098 && TREE_CODE_CLASS (gimple_assign_rhs_code (stmt)) == tcc_comparison)
7100 assignment_p = true;
7101 val = vrp_evaluate_conditional (gimple_assign_rhs_code (stmt),
7102 gimple_assign_rhs1 (stmt),
7103 gimple_assign_rhs2 (stmt),
7106 else if (gimple_code (stmt) == GIMPLE_COND)
7107 val = vrp_evaluate_conditional (gimple_cond_code (stmt),
7108 gimple_cond_lhs (stmt),
7109 gimple_cond_rhs (stmt),
7117 val = fold_convert (gimple_expr_type (stmt), val);
7121 fprintf (dump_file, "Folding predicate ");
7122 print_gimple_expr (dump_file, stmt, 0, 0);
7123 fprintf (dump_file, " to ");
7124 print_generic_expr (dump_file, val, 0);
7125 fprintf (dump_file, "\n");
7128 if (is_gimple_assign (stmt))
7129 gimple_assign_set_rhs_from_tree (si, val);
7132 gcc_assert (gimple_code (stmt) == GIMPLE_COND);
7133 if (integer_zerop (val))
7134 gimple_cond_make_false (stmt);
7135 else if (integer_onep (val))
7136 gimple_cond_make_true (stmt);
7147 /* Callback for substitute_and_fold folding the stmt at *SI. */
7150 vrp_fold_stmt (gimple_stmt_iterator *si)
7152 if (fold_predicate_in (si))
7155 return simplify_stmt_using_ranges (si);
7158 /* Stack of dest,src equivalency pairs that need to be restored after
7159 each attempt to thread a block's incoming edge to an outgoing edge.
7161 A NULL entry is used to mark the end of pairs which need to be
7163 static VEC(tree,heap) *stack;
7165 /* A trivial wrapper so that we can present the generic jump threading
7166 code with a simple API for simplifying statements. STMT is the
7167 statement we want to simplify, WITHIN_STMT provides the location
7168 for any overflow warnings. */
7171 simplify_stmt_for_jump_threading (gimple stmt, gimple within_stmt)
7173 /* We only use VRP information to simplify conditionals. This is
7174 overly conservative, but it's unclear if doing more would be
7175 worth the compile time cost. */
7176 if (gimple_code (stmt) != GIMPLE_COND)
7179 return vrp_evaluate_conditional (gimple_cond_code (stmt),
7180 gimple_cond_lhs (stmt),
7181 gimple_cond_rhs (stmt), within_stmt);
7184 /* Blocks which have more than one predecessor and more than
7185 one successor present jump threading opportunities, i.e.,
7186 when the block is reached from a specific predecessor, we
7187 may be able to determine which of the outgoing edges will
7188 be traversed. When this optimization applies, we are able
7189 to avoid conditionals at runtime and we may expose secondary
7190 optimization opportunities.
7192 This routine is effectively a driver for the generic jump
7193 threading code. It basically just presents the generic code
7194 with edges that may be suitable for jump threading.
7196 Unlike DOM, we do not iterate VRP if jump threading was successful.
7197 While iterating may expose new opportunities for VRP, it is expected
7198 those opportunities would be very limited and the compile time cost
7199 to expose those opportunities would be significant.
7201 As jump threading opportunities are discovered, they are registered
7202 for later realization. */
7205 identify_jump_threads (void)
7212 /* Ugh. When substituting values earlier in this pass we can
7213 wipe the dominance information. So rebuild the dominator
7214 information as we need it within the jump threading code. */
7215 calculate_dominance_info (CDI_DOMINATORS);
7217 /* We do not allow VRP information to be used for jump threading
7218 across a back edge in the CFG. Otherwise it becomes too
7219 difficult to avoid eliminating loop exit tests. Of course
7220 EDGE_DFS_BACK is not accurate at this time so we have to
7222 mark_dfs_back_edges ();
7224 /* Do not thread across edges we are about to remove. Just marking
7225 them as EDGE_DFS_BACK will do. */
7226 for (i = 0; VEC_iterate (edge, to_remove_edges, i, e); ++i)
7227 e->flags |= EDGE_DFS_BACK;
7229 /* Allocate our unwinder stack to unwind any temporary equivalences
7230 that might be recorded. */
7231 stack = VEC_alloc (tree, heap, 20);
7233 /* To avoid lots of silly node creation, we create a single
7234 conditional and just modify it in-place when attempting to
7236 dummy = gimple_build_cond (EQ_EXPR,
7237 integer_zero_node, integer_zero_node,
7240 /* Walk through all the blocks finding those which present a
7241 potential jump threading opportunity. We could set this up
7242 as a dominator walker and record data during the walk, but
7243 I doubt it's worth the effort for the classes of jump
7244 threading opportunities we are trying to identify at this
7245 point in compilation. */
7250 /* If the generic jump threading code does not find this block
7251 interesting, then there is nothing to do. */
7252 if (! potentially_threadable_block (bb))
7255 /* We only care about blocks ending in a COND_EXPR. While there
7256 may be some value in handling SWITCH_EXPR here, I doubt it's
7257 terribly important. */
7258 last = gsi_stmt (gsi_last_bb (bb));
7259 if (gimple_code (last) != GIMPLE_COND)
7262 /* We're basically looking for any kind of conditional with
7263 integral type arguments. */
7264 if (TREE_CODE (gimple_cond_lhs (last)) == SSA_NAME
7265 && INTEGRAL_TYPE_P (TREE_TYPE (gimple_cond_lhs (last)))
7266 && (TREE_CODE (gimple_cond_rhs (last)) == SSA_NAME
7267 || is_gimple_min_invariant (gimple_cond_rhs (last)))
7268 && INTEGRAL_TYPE_P (TREE_TYPE (gimple_cond_rhs (last))))
7272 /* We've got a block with multiple predecessors and multiple
7273 successors which also ends in a suitable conditional. For
7274 each predecessor, see if we can thread it to a specific
7276 FOR_EACH_EDGE (e, ei, bb->preds)
7278 /* Do not thread across back edges or abnormal edges
7280 if (e->flags & (EDGE_DFS_BACK | EDGE_COMPLEX))
7283 thread_across_edge (dummy, e, true, &stack,
7284 simplify_stmt_for_jump_threading);
7289 /* We do not actually update the CFG or SSA graphs at this point as
7290 ASSERT_EXPRs are still in the IL and cfg cleanup code does not yet
7291 handle ASSERT_EXPRs gracefully. */
7294 /* We identified all the jump threading opportunities earlier, but could
7295 not transform the CFG at that time. This routine transforms the
7296 CFG and arranges for the dominator tree to be rebuilt if necessary.
7298 Note the SSA graph update will occur during the normal TODO
7299 processing by the pass manager. */
7301 finalize_jump_threads (void)
7303 thread_through_all_blocks (false);
7304 VEC_free (tree, heap, stack);
7308 /* Traverse all the blocks folding conditionals with known ranges. */
7314 prop_value_t *single_val_range;
7315 bool do_value_subst_p;
7319 fprintf (dump_file, "\nValue ranges after VRP:\n\n");
7320 dump_all_value_ranges (dump_file);
7321 fprintf (dump_file, "\n");
7324 /* We may have ended with ranges that have exactly one value. Those
7325 values can be substituted as any other const propagated
7326 value using substitute_and_fold. */
7327 single_val_range = XCNEWVEC (prop_value_t, num_ssa_names);
7329 do_value_subst_p = false;
7330 for (i = 0; i < num_ssa_names; i++)
7332 && vr_value[i]->type == VR_RANGE
7333 && vr_value[i]->min == vr_value[i]->max
7334 && is_gimple_min_invariant (vr_value[i]->min))
7336 single_val_range[i].value = vr_value[i]->min;
7337 do_value_subst_p = true;
7340 if (!do_value_subst_p)
7342 /* We found no single-valued ranges, don't waste time trying to
7343 do single value substitution in substitute_and_fold. */
7344 free (single_val_range);
7345 single_val_range = NULL;
7348 substitute_and_fold (single_val_range, vrp_fold_stmt);
7350 if (warn_array_bounds)
7351 check_all_array_refs ();
7353 /* We must identify jump threading opportunities before we release
7354 the datastructures built by VRP. */
7355 identify_jump_threads ();
7357 /* Free allocated memory. */
7358 for (i = 0; i < num_ssa_names; i++)
7361 BITMAP_FREE (vr_value[i]->equiv);
7365 free (single_val_range);
7367 free (vr_phi_edge_counts);
7369 /* So that we can distinguish between VRP data being available
7370 and not available. */
7372 vr_phi_edge_counts = NULL;
7376 /* Main entry point to VRP (Value Range Propagation). This pass is
7377 loosely based on J. R. C. Patterson, ``Accurate Static Branch
7378 Prediction by Value Range Propagation,'' in SIGPLAN Conference on
7379 Programming Language Design and Implementation, pp. 67-78, 1995.
7380 Also available at http://citeseer.ist.psu.edu/patterson95accurate.html
7382 This is essentially an SSA-CCP pass modified to deal with ranges
7383 instead of constants.
7385 While propagating ranges, we may find that two or more SSA name
7386 have equivalent, though distinct ranges. For instance,
7389 2 p_4 = ASSERT_EXPR <p_3, p_3 != 0>
7391 4 p_5 = ASSERT_EXPR <p_4, p_4 == q_2>;
7395 In the code above, pointer p_5 has range [q_2, q_2], but from the
7396 code we can also determine that p_5 cannot be NULL and, if q_2 had
7397 a non-varying range, p_5's range should also be compatible with it.
7399 These equivalences are created by two expressions: ASSERT_EXPR and
7400 copy operations. Since p_5 is an assertion on p_4, and p_4 was the
7401 result of another assertion, then we can use the fact that p_5 and
7402 p_4 are equivalent when evaluating p_5's range.
7404 Together with value ranges, we also propagate these equivalences
7405 between names so that we can take advantage of information from
7406 multiple ranges when doing final replacement. Note that this
7407 equivalency relation is transitive but not symmetric.
7409 In the example above, p_5 is equivalent to p_4, q_2 and p_3, but we
7410 cannot assert that q_2 is equivalent to p_5 because q_2 may be used
7411 in contexts where that assertion does not hold (e.g., in line 6).
7413 TODO, the main difference between this pass and Patterson's is that
7414 we do not propagate edge probabilities. We only compute whether
7415 edges can be taken or not. That is, instead of having a spectrum
7416 of jump probabilities between 0 and 1, we only deal with 0, 1 and
7417 DON'T KNOW. In the future, it may be worthwhile to propagate
7418 probabilities to aid branch prediction. */
7427 loop_optimizer_init (LOOPS_NORMAL | LOOPS_HAVE_RECORDED_EXITS);
7428 rewrite_into_loop_closed_ssa (NULL, TODO_update_ssa);
7431 insert_range_assertions ();
7433 to_remove_edges = VEC_alloc (edge, heap, 10);
7434 to_update_switch_stmts = VEC_alloc (switch_update, heap, 5);
7435 threadedge_initialize_values ();
7438 ssa_propagate (vrp_visit_stmt, vrp_visit_phi_node);
7441 /* ASSERT_EXPRs must be removed before finalizing jump threads
7442 as finalizing jump threads calls the CFG cleanup code which
7443 does not properly handle ASSERT_EXPRs. */
7444 remove_range_assertions ();
7446 /* If we exposed any new variables, go ahead and put them into
7447 SSA form now, before we handle jump threading. This simplifies
7448 interactions between rewriting of _DECL nodes into SSA form
7449 and rewriting SSA_NAME nodes into SSA form after block
7450 duplication and CFG manipulation. */
7451 update_ssa (TODO_update_ssa);
7453 finalize_jump_threads ();
7455 /* Remove dead edges from SWITCH_EXPR optimization. This leaves the
7456 CFG in a broken state and requires a cfg_cleanup run. */
7457 for (i = 0; VEC_iterate (edge, to_remove_edges, i, e); ++i)
7459 /* Update SWITCH_EXPR case label vector. */
7460 for (i = 0; VEC_iterate (switch_update, to_update_switch_stmts, i, su); ++i)
7463 size_t n = TREE_VEC_LENGTH (su->vec);
7465 gimple_switch_set_num_labels (su->stmt, n);
7466 for (j = 0; j < n; j++)
7467 gimple_switch_set_label (su->stmt, j, TREE_VEC_ELT (su->vec, j));
7468 /* As we may have replaced the default label with a regular one
7469 make sure to make it a real default label again. This ensures
7470 optimal expansion. */
7471 label = gimple_switch_default_label (su->stmt);
7472 CASE_LOW (label) = NULL_TREE;
7473 CASE_HIGH (label) = NULL_TREE;
7476 if (VEC_length (edge, to_remove_edges) > 0)
7477 free_dominance_info (CDI_DOMINATORS);
7479 VEC_free (edge, heap, to_remove_edges);
7480 VEC_free (switch_update, heap, to_update_switch_stmts);
7481 threadedge_finalize_values ();
7484 loop_optimizer_finalize ();
7491 return flag_tree_vrp != 0;
7494 struct gimple_opt_pass pass_vrp =
7499 gate_vrp, /* gate */
7500 execute_vrp, /* execute */
7503 0, /* static_pass_number */
7504 TV_TREE_VRP, /* tv_id */
7505 PROP_ssa, /* properties_required */
7506 0, /* properties_provided */
7507 0, /* properties_destroyed */
7508 0, /* todo_flags_start */
7513 | TODO_update_ssa /* todo_flags_finish */