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 != RSHIFT_EXPR
2090 && code != BIT_AND_EXPR
2091 && code != BIT_IOR_EXPR
2092 && code != TRUTH_AND_EXPR
2093 && code != TRUTH_OR_EXPR)
2095 /* We can still do constant propagation here. */
2096 tree const_op0 = op_with_constant_singleton_value_range (op0);
2097 tree const_op1 = op_with_constant_singleton_value_range (op1);
2098 if (const_op0 || const_op1)
2100 tree tem = fold_binary (code, expr_type,
2101 const_op0 ? const_op0 : op0,
2102 const_op1 ? const_op1 : op1);
2104 && is_gimple_min_invariant (tem)
2105 && !is_overflow_infinity (tem))
2107 set_value_range (vr, VR_RANGE, tem, tem, NULL);
2111 set_value_range_to_varying (vr);
2115 /* Get value ranges for each operand. For constant operands, create
2116 a new value range with the operand to simplify processing. */
2117 if (TREE_CODE (op0) == SSA_NAME)
2118 vr0 = *(get_value_range (op0));
2119 else if (is_gimple_min_invariant (op0))
2120 set_value_range_to_value (&vr0, op0, NULL);
2122 set_value_range_to_varying (&vr0);
2124 if (TREE_CODE (op1) == SSA_NAME)
2125 vr1 = *(get_value_range (op1));
2126 else if (is_gimple_min_invariant (op1))
2127 set_value_range_to_value (&vr1, op1, NULL);
2129 set_value_range_to_varying (&vr1);
2131 /* If either range is UNDEFINED, so is the result. */
2132 if (vr0.type == VR_UNDEFINED || vr1.type == VR_UNDEFINED)
2134 set_value_range_to_undefined (vr);
2138 /* The type of the resulting value range defaults to VR0.TYPE. */
2141 /* Refuse to operate on VARYING ranges, ranges of different kinds
2142 and symbolic ranges. As an exception, we allow BIT_AND_EXPR
2143 because we may be able to derive a useful range even if one of
2144 the operands is VR_VARYING or symbolic range. Similarly for
2145 divisions. TODO, we may be able to derive anti-ranges in
2147 if (code != BIT_AND_EXPR
2148 && code != TRUTH_AND_EXPR
2149 && code != TRUTH_OR_EXPR
2150 && code != TRUNC_DIV_EXPR
2151 && code != FLOOR_DIV_EXPR
2152 && code != CEIL_DIV_EXPR
2153 && code != EXACT_DIV_EXPR
2154 && code != ROUND_DIV_EXPR
2155 && code != TRUNC_MOD_EXPR
2156 && (vr0.type == VR_VARYING
2157 || vr1.type == VR_VARYING
2158 || vr0.type != vr1.type
2159 || symbolic_range_p (&vr0)
2160 || symbolic_range_p (&vr1)))
2162 set_value_range_to_varying (vr);
2166 /* Now evaluate the expression to determine the new range. */
2167 if (POINTER_TYPE_P (expr_type)
2168 || POINTER_TYPE_P (TREE_TYPE (op0))
2169 || POINTER_TYPE_P (TREE_TYPE (op1)))
2171 if (code == MIN_EXPR || code == MAX_EXPR)
2173 /* For MIN/MAX expressions with pointers, we only care about
2174 nullness, if both are non null, then the result is nonnull.
2175 If both are null, then the result is null. Otherwise they
2177 if (range_is_nonnull (&vr0) && range_is_nonnull (&vr1))
2178 set_value_range_to_nonnull (vr, expr_type);
2179 else if (range_is_null (&vr0) && range_is_null (&vr1))
2180 set_value_range_to_null (vr, expr_type);
2182 set_value_range_to_varying (vr);
2186 gcc_assert (code == POINTER_PLUS_EXPR);
2187 /* For pointer types, we are really only interested in asserting
2188 whether the expression evaluates to non-NULL. */
2189 if (range_is_nonnull (&vr0) || range_is_nonnull (&vr1))
2190 set_value_range_to_nonnull (vr, expr_type);
2191 else if (range_is_null (&vr0) && range_is_null (&vr1))
2192 set_value_range_to_null (vr, expr_type);
2194 set_value_range_to_varying (vr);
2199 /* For integer ranges, apply the operation to each end of the
2200 range and see what we end up with. */
2201 if (code == TRUTH_AND_EXPR
2202 || code == TRUTH_OR_EXPR)
2204 /* If one of the operands is zero, we know that the whole
2205 expression evaluates zero. */
2206 if (code == TRUTH_AND_EXPR
2207 && ((vr0.type == VR_RANGE
2208 && integer_zerop (vr0.min)
2209 && integer_zerop (vr0.max))
2210 || (vr1.type == VR_RANGE
2211 && integer_zerop (vr1.min)
2212 && integer_zerop (vr1.max))))
2215 min = max = build_int_cst (expr_type, 0);
2217 /* If one of the operands is one, we know that the whole
2218 expression evaluates one. */
2219 else if (code == TRUTH_OR_EXPR
2220 && ((vr0.type == VR_RANGE
2221 && integer_onep (vr0.min)
2222 && integer_onep (vr0.max))
2223 || (vr1.type == VR_RANGE
2224 && integer_onep (vr1.min)
2225 && integer_onep (vr1.max))))
2228 min = max = build_int_cst (expr_type, 1);
2230 else if (vr0.type != VR_VARYING
2231 && vr1.type != VR_VARYING
2232 && vr0.type == vr1.type
2233 && !symbolic_range_p (&vr0)
2234 && !overflow_infinity_range_p (&vr0)
2235 && !symbolic_range_p (&vr1)
2236 && !overflow_infinity_range_p (&vr1))
2238 /* Boolean expressions cannot be folded with int_const_binop. */
2239 min = fold_binary (code, expr_type, vr0.min, vr1.min);
2240 max = fold_binary (code, expr_type, vr0.max, vr1.max);
2244 /* The result of a TRUTH_*_EXPR is always true or false. */
2245 set_value_range_to_truthvalue (vr, expr_type);
2249 else if (code == PLUS_EXPR
2251 || code == MAX_EXPR)
2253 /* If we have a PLUS_EXPR with two VR_ANTI_RANGEs, drop to
2254 VR_VARYING. It would take more effort to compute a precise
2255 range for such a case. For example, if we have op0 == 1 and
2256 op1 == -1 with their ranges both being ~[0,0], we would have
2257 op0 + op1 == 0, so we cannot claim that the sum is in ~[0,0].
2258 Note that we are guaranteed to have vr0.type == vr1.type at
2260 if (code == PLUS_EXPR && vr0.type == VR_ANTI_RANGE)
2262 set_value_range_to_varying (vr);
2266 /* For operations that make the resulting range directly
2267 proportional to the original ranges, apply the operation to
2268 the same end of each range. */
2269 min = vrp_int_const_binop (code, vr0.min, vr1.min);
2270 max = vrp_int_const_binop (code, vr0.max, vr1.max);
2272 /* If both additions overflowed the range kind is still correct.
2273 This happens regularly with subtracting something in unsigned
2275 ??? See PR30318 for all the cases we do not handle. */
2276 if (code == PLUS_EXPR
2277 && (TREE_OVERFLOW (min) && !is_overflow_infinity (min))
2278 && (TREE_OVERFLOW (max) && !is_overflow_infinity (max)))
2280 min = build_int_cst_wide (TREE_TYPE (min),
2281 TREE_INT_CST_LOW (min),
2282 TREE_INT_CST_HIGH (min));
2283 max = build_int_cst_wide (TREE_TYPE (max),
2284 TREE_INT_CST_LOW (max),
2285 TREE_INT_CST_HIGH (max));
2288 else if (code == MULT_EXPR
2289 || code == TRUNC_DIV_EXPR
2290 || code == FLOOR_DIV_EXPR
2291 || code == CEIL_DIV_EXPR
2292 || code == EXACT_DIV_EXPR
2293 || code == ROUND_DIV_EXPR
2294 || code == RSHIFT_EXPR)
2300 /* If we have an unsigned MULT_EXPR with two VR_ANTI_RANGEs,
2301 drop to VR_VARYING. It would take more effort to compute a
2302 precise range for such a case. For example, if we have
2303 op0 == 65536 and op1 == 65536 with their ranges both being
2304 ~[0,0] on a 32-bit machine, we would have op0 * op1 == 0, so
2305 we cannot claim that the product is in ~[0,0]. Note that we
2306 are guaranteed to have vr0.type == vr1.type at this
2308 if (code == MULT_EXPR
2309 && vr0.type == VR_ANTI_RANGE
2310 && !TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (op0)))
2312 set_value_range_to_varying (vr);
2316 /* If we have a RSHIFT_EXPR with any shift values outside [0..prec-1],
2317 then drop to VR_VARYING. Outside of this range we get undefined
2318 behavior from the shift operation. We cannot even trust
2319 SHIFT_COUNT_TRUNCATED at this stage, because that applies to rtl
2320 shifts, and the operation at the tree level may be widened. */
2321 if (code == RSHIFT_EXPR)
2323 if (vr1.type == VR_ANTI_RANGE
2324 || !vrp_expr_computes_nonnegative (op1, &sop)
2326 (build_int_cst (TREE_TYPE (vr1.max),
2327 TYPE_PRECISION (expr_type) - 1),
2330 set_value_range_to_varying (vr);
2335 else if ((code == TRUNC_DIV_EXPR
2336 || code == FLOOR_DIV_EXPR
2337 || code == CEIL_DIV_EXPR
2338 || code == EXACT_DIV_EXPR
2339 || code == ROUND_DIV_EXPR)
2340 && (vr0.type != VR_RANGE || symbolic_range_p (&vr0)))
2342 /* For division, if op1 has VR_RANGE but op0 does not, something
2343 can be deduced just from that range. Say [min, max] / [4, max]
2344 gives [min / 4, max / 4] range. */
2345 if (vr1.type == VR_RANGE
2346 && !symbolic_range_p (&vr1)
2347 && !range_includes_zero_p (&vr1))
2349 vr0.type = type = VR_RANGE;
2350 vr0.min = vrp_val_min (TREE_TYPE (op0));
2351 vr0.max = vrp_val_max (TREE_TYPE (op1));
2355 set_value_range_to_varying (vr);
2360 /* For divisions, if op0 is VR_RANGE, we can deduce a range
2361 even if op1 is VR_VARYING, VR_ANTI_RANGE, symbolic or can
2363 if ((code == TRUNC_DIV_EXPR
2364 || code == FLOOR_DIV_EXPR
2365 || code == CEIL_DIV_EXPR
2366 || code == EXACT_DIV_EXPR
2367 || code == ROUND_DIV_EXPR)
2368 && vr0.type == VR_RANGE
2369 && (vr1.type != VR_RANGE
2370 || symbolic_range_p (&vr1)
2371 || range_includes_zero_p (&vr1)))
2373 tree zero = build_int_cst (TREE_TYPE (vr0.min), 0);
2379 if (vrp_expr_computes_nonnegative (op1, &sop) && !sop)
2381 /* For unsigned division or when divisor is known
2382 to be non-negative, the range has to cover
2383 all numbers from 0 to max for positive max
2384 and all numbers from min to 0 for negative min. */
2385 cmp = compare_values (vr0.max, zero);
2388 else if (cmp == 0 || cmp == 1)
2392 cmp = compare_values (vr0.min, zero);
2395 else if (cmp == 0 || cmp == -1)
2402 /* Otherwise the range is -max .. max or min .. -min
2403 depending on which bound is bigger in absolute value,
2404 as the division can change the sign. */
2405 abs_extent_range (vr, vr0.min, vr0.max);
2408 if (type == VR_VARYING)
2410 set_value_range_to_varying (vr);
2415 /* Multiplications and divisions are a bit tricky to handle,
2416 depending on the mix of signs we have in the two ranges, we
2417 need to operate on different values to get the minimum and
2418 maximum values for the new range. One approach is to figure
2419 out all the variations of range combinations and do the
2422 However, this involves several calls to compare_values and it
2423 is pretty convoluted. It's simpler to do the 4 operations
2424 (MIN0 OP MIN1, MIN0 OP MAX1, MAX0 OP MIN1 and MAX0 OP MAX0 OP
2425 MAX1) and then figure the smallest and largest values to form
2429 gcc_assert ((vr0.type == VR_RANGE
2430 || (code == MULT_EXPR && vr0.type == VR_ANTI_RANGE))
2431 && vr0.type == vr1.type);
2433 /* Compute the 4 cross operations. */
2435 val[0] = vrp_int_const_binop (code, vr0.min, vr1.min);
2436 if (val[0] == NULL_TREE)
2439 if (vr1.max == vr1.min)
2443 val[1] = vrp_int_const_binop (code, vr0.min, vr1.max);
2444 if (val[1] == NULL_TREE)
2448 if (vr0.max == vr0.min)
2452 val[2] = vrp_int_const_binop (code, vr0.max, vr1.min);
2453 if (val[2] == NULL_TREE)
2457 if (vr0.min == vr0.max || vr1.min == vr1.max)
2461 val[3] = vrp_int_const_binop (code, vr0.max, vr1.max);
2462 if (val[3] == NULL_TREE)
2468 set_value_range_to_varying (vr);
2472 /* Set MIN to the minimum of VAL[i] and MAX to the maximum
2476 for (i = 1; i < 4; i++)
2478 if (!is_gimple_min_invariant (min)
2479 || (TREE_OVERFLOW (min) && !is_overflow_infinity (min))
2480 || !is_gimple_min_invariant (max)
2481 || (TREE_OVERFLOW (max) && !is_overflow_infinity (max)))
2486 if (!is_gimple_min_invariant (val[i])
2487 || (TREE_OVERFLOW (val[i])
2488 && !is_overflow_infinity (val[i])))
2490 /* If we found an overflowed value, set MIN and MAX
2491 to it so that we set the resulting range to
2497 if (compare_values (val[i], min) == -1)
2500 if (compare_values (val[i], max) == 1)
2506 else if (code == TRUNC_MOD_EXPR)
2509 if (vr1.type != VR_RANGE
2510 || symbolic_range_p (&vr1)
2511 || range_includes_zero_p (&vr1)
2512 || vrp_val_is_min (vr1.min))
2514 set_value_range_to_varying (vr);
2518 /* Compute MAX <|vr1.min|, |vr1.max|> - 1. */
2519 max = fold_unary_to_constant (ABS_EXPR, TREE_TYPE (vr1.min), vr1.min);
2520 if (tree_int_cst_lt (max, vr1.max))
2522 max = int_const_binop (MINUS_EXPR, max, integer_one_node, 0);
2523 /* If the dividend is non-negative the modulus will be
2524 non-negative as well. */
2525 if (TYPE_UNSIGNED (TREE_TYPE (max))
2526 || (vrp_expr_computes_nonnegative (op0, &sop) && !sop))
2527 min = build_int_cst (TREE_TYPE (max), 0);
2529 min = fold_unary_to_constant (NEGATE_EXPR, TREE_TYPE (max), max);
2531 else if (code == MINUS_EXPR)
2533 /* If we have a MINUS_EXPR with two VR_ANTI_RANGEs, drop to
2534 VR_VARYING. It would take more effort to compute a precise
2535 range for such a case. For example, if we have op0 == 1 and
2536 op1 == 1 with their ranges both being ~[0,0], we would have
2537 op0 - op1 == 0, so we cannot claim that the difference is in
2538 ~[0,0]. Note that we are guaranteed to have
2539 vr0.type == vr1.type at this point. */
2540 if (vr0.type == VR_ANTI_RANGE)
2542 set_value_range_to_varying (vr);
2546 /* For MINUS_EXPR, apply the operation to the opposite ends of
2548 min = vrp_int_const_binop (code, vr0.min, vr1.max);
2549 max = vrp_int_const_binop (code, vr0.max, vr1.min);
2551 else if (code == BIT_AND_EXPR)
2553 bool vr0_int_cst_singleton_p, vr1_int_cst_singleton_p;
2555 vr0_int_cst_singleton_p = range_int_cst_singleton_p (&vr0);
2556 vr1_int_cst_singleton_p = range_int_cst_singleton_p (&vr1);
2558 if (vr0_int_cst_singleton_p && vr1_int_cst_singleton_p)
2559 min = max = int_const_binop (code, vr0.max, vr1.max, 0);
2560 else if (vr0_int_cst_singleton_p
2561 && tree_int_cst_sgn (vr0.max) >= 0)
2563 min = build_int_cst (expr_type, 0);
2566 else if (vr1_int_cst_singleton_p
2567 && tree_int_cst_sgn (vr1.max) >= 0)
2570 min = build_int_cst (expr_type, 0);
2575 set_value_range_to_varying (vr);
2579 else if (code == BIT_IOR_EXPR)
2581 if (range_int_cst_p (&vr0)
2582 && range_int_cst_p (&vr1)
2583 && tree_int_cst_sgn (vr0.min) >= 0
2584 && tree_int_cst_sgn (vr1.min) >= 0)
2586 double_int vr0_max = tree_to_double_int (vr0.max);
2587 double_int vr1_max = tree_to_double_int (vr1.max);
2590 /* Set all bits to the right of the most significant one to 1.
2591 For example, [0, 4] | [4, 4] = [4, 7]. */
2592 ior_max.low = vr0_max.low | vr1_max.low;
2593 ior_max.high = vr0_max.high | vr1_max.high;
2594 if (ior_max.high != 0)
2596 ior_max.low = ~(unsigned HOST_WIDE_INT)0u;
2597 ior_max.high |= ((HOST_WIDE_INT) 1
2598 << floor_log2 (ior_max.high)) - 1;
2600 else if (ior_max.low != 0)
2601 ior_max.low |= ((unsigned HOST_WIDE_INT) 1u
2602 << floor_log2 (ior_max.low)) - 1;
2604 /* Both of these endpoints are conservative. */
2605 min = vrp_int_const_binop (MAX_EXPR, vr0.min, vr1.min);
2606 max = double_int_to_tree (expr_type, ior_max);
2610 set_value_range_to_varying (vr);
2617 /* If either MIN or MAX overflowed, then set the resulting range to
2618 VARYING. But we do accept an overflow infinity
2620 if (min == NULL_TREE
2621 || !is_gimple_min_invariant (min)
2622 || (TREE_OVERFLOW (min) && !is_overflow_infinity (min))
2624 || !is_gimple_min_invariant (max)
2625 || (TREE_OVERFLOW (max) && !is_overflow_infinity (max)))
2627 set_value_range_to_varying (vr);
2633 2) [-INF, +-INF(OVF)]
2634 3) [+-INF(OVF), +INF]
2635 4) [+-INF(OVF), +-INF(OVF)]
2636 We learn nothing when we have INF and INF(OVF) on both sides.
2637 Note that we do accept [-INF, -INF] and [+INF, +INF] without
2639 if ((vrp_val_is_min (min) || is_overflow_infinity (min))
2640 && (vrp_val_is_max (max) || is_overflow_infinity (max)))
2642 set_value_range_to_varying (vr);
2646 cmp = compare_values (min, max);
2647 if (cmp == -2 || cmp == 1)
2649 /* If the new range has its limits swapped around (MIN > MAX),
2650 then the operation caused one of them to wrap around, mark
2651 the new range VARYING. */
2652 set_value_range_to_varying (vr);
2655 set_value_range (vr, type, min, max, NULL);
2659 /* Extract range information from a unary expression EXPR based on
2660 the range of its operand and the expression code. */
2663 extract_range_from_unary_expr (value_range_t *vr, enum tree_code code,
2664 tree type, tree op0)
2668 value_range_t vr0 = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
2670 /* Refuse to operate on certain unary expressions for which we
2671 cannot easily determine a resulting range. */
2672 if (code == FIX_TRUNC_EXPR
2673 || code == FLOAT_EXPR
2674 || code == BIT_NOT_EXPR
2675 || code == CONJ_EXPR)
2677 /* We can still do constant propagation here. */
2678 if ((op0 = op_with_constant_singleton_value_range (op0)) != NULL_TREE)
2680 tree tem = fold_unary (code, type, op0);
2682 && is_gimple_min_invariant (tem)
2683 && !is_overflow_infinity (tem))
2685 set_value_range (vr, VR_RANGE, tem, tem, NULL);
2689 set_value_range_to_varying (vr);
2693 /* Get value ranges for the operand. For constant operands, create
2694 a new value range with the operand to simplify processing. */
2695 if (TREE_CODE (op0) == SSA_NAME)
2696 vr0 = *(get_value_range (op0));
2697 else if (is_gimple_min_invariant (op0))
2698 set_value_range_to_value (&vr0, op0, NULL);
2700 set_value_range_to_varying (&vr0);
2702 /* If VR0 is UNDEFINED, so is the result. */
2703 if (vr0.type == VR_UNDEFINED)
2705 set_value_range_to_undefined (vr);
2709 /* Refuse to operate on symbolic ranges, or if neither operand is
2710 a pointer or integral type. */
2711 if ((!INTEGRAL_TYPE_P (TREE_TYPE (op0))
2712 && !POINTER_TYPE_P (TREE_TYPE (op0)))
2713 || (vr0.type != VR_VARYING
2714 && symbolic_range_p (&vr0)))
2716 set_value_range_to_varying (vr);
2720 /* If the expression involves pointers, we are only interested in
2721 determining if it evaluates to NULL [0, 0] or non-NULL (~[0, 0]). */
2722 if (POINTER_TYPE_P (type) || POINTER_TYPE_P (TREE_TYPE (op0)))
2727 if (range_is_nonnull (&vr0)
2728 || (tree_unary_nonzero_warnv_p (code, type, op0, &sop)
2730 set_value_range_to_nonnull (vr, type);
2731 else if (range_is_null (&vr0))
2732 set_value_range_to_null (vr, type);
2734 set_value_range_to_varying (vr);
2739 /* Handle unary expressions on integer ranges. */
2740 if (CONVERT_EXPR_CODE_P (code)
2741 && INTEGRAL_TYPE_P (type)
2742 && INTEGRAL_TYPE_P (TREE_TYPE (op0)))
2744 tree inner_type = TREE_TYPE (op0);
2745 tree outer_type = type;
2747 /* If VR0 is varying and we increase the type precision, assume
2748 a full range for the following transformation. */
2749 if (vr0.type == VR_VARYING
2750 && TYPE_PRECISION (inner_type) < TYPE_PRECISION (outer_type))
2752 vr0.type = VR_RANGE;
2753 vr0.min = TYPE_MIN_VALUE (inner_type);
2754 vr0.max = TYPE_MAX_VALUE (inner_type);
2757 /* If VR0 is a constant range or anti-range and the conversion is
2758 not truncating we can convert the min and max values and
2759 canonicalize the resulting range. Otherwise we can do the
2760 conversion if the size of the range is less than what the
2761 precision of the target type can represent and the range is
2762 not an anti-range. */
2763 if ((vr0.type == VR_RANGE
2764 || vr0.type == VR_ANTI_RANGE)
2765 && TREE_CODE (vr0.min) == INTEGER_CST
2766 && TREE_CODE (vr0.max) == INTEGER_CST
2767 && (!is_overflow_infinity (vr0.min)
2768 || (vr0.type == VR_RANGE
2769 && TYPE_PRECISION (outer_type) > TYPE_PRECISION (inner_type)
2770 && needs_overflow_infinity (outer_type)
2771 && supports_overflow_infinity (outer_type)))
2772 && (!is_overflow_infinity (vr0.max)
2773 || (vr0.type == VR_RANGE
2774 && TYPE_PRECISION (outer_type) > TYPE_PRECISION (inner_type)
2775 && needs_overflow_infinity (outer_type)
2776 && supports_overflow_infinity (outer_type)))
2777 && (TYPE_PRECISION (outer_type) >= TYPE_PRECISION (inner_type)
2778 || (vr0.type == VR_RANGE
2779 && integer_zerop (int_const_binop (RSHIFT_EXPR,
2780 int_const_binop (MINUS_EXPR, vr0.max, vr0.min, 0),
2781 size_int (TYPE_PRECISION (outer_type)), 0)))))
2783 tree new_min, new_max;
2784 new_min = force_fit_type_double (outer_type,
2785 TREE_INT_CST_LOW (vr0.min),
2786 TREE_INT_CST_HIGH (vr0.min), 0, 0);
2787 new_max = force_fit_type_double (outer_type,
2788 TREE_INT_CST_LOW (vr0.max),
2789 TREE_INT_CST_HIGH (vr0.max), 0, 0);
2790 if (is_overflow_infinity (vr0.min))
2791 new_min = negative_overflow_infinity (outer_type);
2792 if (is_overflow_infinity (vr0.max))
2793 new_max = positive_overflow_infinity (outer_type);
2794 set_and_canonicalize_value_range (vr, vr0.type,
2795 new_min, new_max, NULL);
2799 set_value_range_to_varying (vr);
2803 /* Conversion of a VR_VARYING value to a wider type can result
2804 in a usable range. So wait until after we've handled conversions
2805 before dropping the result to VR_VARYING if we had a source
2806 operand that is VR_VARYING. */
2807 if (vr0.type == VR_VARYING)
2809 set_value_range_to_varying (vr);
2813 /* Apply the operation to each end of the range and see what we end
2815 if (code == NEGATE_EXPR
2816 && !TYPE_UNSIGNED (type))
2818 /* NEGATE_EXPR flips the range around. We need to treat
2819 TYPE_MIN_VALUE specially. */
2820 if (is_positive_overflow_infinity (vr0.max))
2821 min = negative_overflow_infinity (type);
2822 else if (is_negative_overflow_infinity (vr0.max))
2823 min = positive_overflow_infinity (type);
2824 else if (!vrp_val_is_min (vr0.max))
2825 min = fold_unary_to_constant (code, type, vr0.max);
2826 else if (needs_overflow_infinity (type))
2828 if (supports_overflow_infinity (type)
2829 && !is_overflow_infinity (vr0.min)
2830 && !vrp_val_is_min (vr0.min))
2831 min = positive_overflow_infinity (type);
2834 set_value_range_to_varying (vr);
2839 min = TYPE_MIN_VALUE (type);
2841 if (is_positive_overflow_infinity (vr0.min))
2842 max = negative_overflow_infinity (type);
2843 else if (is_negative_overflow_infinity (vr0.min))
2844 max = positive_overflow_infinity (type);
2845 else if (!vrp_val_is_min (vr0.min))
2846 max = fold_unary_to_constant (code, type, vr0.min);
2847 else if (needs_overflow_infinity (type))
2849 if (supports_overflow_infinity (type))
2850 max = positive_overflow_infinity (type);
2853 set_value_range_to_varying (vr);
2858 max = TYPE_MIN_VALUE (type);
2860 else if (code == NEGATE_EXPR
2861 && TYPE_UNSIGNED (type))
2863 if (!range_includes_zero_p (&vr0))
2865 max = fold_unary_to_constant (code, type, vr0.min);
2866 min = fold_unary_to_constant (code, type, vr0.max);
2870 if (range_is_null (&vr0))
2871 set_value_range_to_null (vr, type);
2873 set_value_range_to_varying (vr);
2877 else if (code == ABS_EXPR
2878 && !TYPE_UNSIGNED (type))
2880 /* -TYPE_MIN_VALUE = TYPE_MIN_VALUE with flag_wrapv so we can't get a
2882 if (!TYPE_OVERFLOW_UNDEFINED (type)
2883 && ((vr0.type == VR_RANGE
2884 && vrp_val_is_min (vr0.min))
2885 || (vr0.type == VR_ANTI_RANGE
2886 && !vrp_val_is_min (vr0.min)
2887 && !range_includes_zero_p (&vr0))))
2889 set_value_range_to_varying (vr);
2893 /* ABS_EXPR may flip the range around, if the original range
2894 included negative values. */
2895 if (is_overflow_infinity (vr0.min))
2896 min = positive_overflow_infinity (type);
2897 else if (!vrp_val_is_min (vr0.min))
2898 min = fold_unary_to_constant (code, type, vr0.min);
2899 else if (!needs_overflow_infinity (type))
2900 min = TYPE_MAX_VALUE (type);
2901 else if (supports_overflow_infinity (type))
2902 min = positive_overflow_infinity (type);
2905 set_value_range_to_varying (vr);
2909 if (is_overflow_infinity (vr0.max))
2910 max = positive_overflow_infinity (type);
2911 else if (!vrp_val_is_min (vr0.max))
2912 max = fold_unary_to_constant (code, type, vr0.max);
2913 else if (!needs_overflow_infinity (type))
2914 max = TYPE_MAX_VALUE (type);
2915 else if (supports_overflow_infinity (type)
2916 /* We shouldn't generate [+INF, +INF] as set_value_range
2917 doesn't like this and ICEs. */
2918 && !is_positive_overflow_infinity (min))
2919 max = positive_overflow_infinity (type);
2922 set_value_range_to_varying (vr);
2926 cmp = compare_values (min, max);
2928 /* If a VR_ANTI_RANGEs contains zero, then we have
2929 ~[-INF, min(MIN, MAX)]. */
2930 if (vr0.type == VR_ANTI_RANGE)
2932 if (range_includes_zero_p (&vr0))
2934 /* Take the lower of the two values. */
2938 /* Create ~[-INF, min (abs(MIN), abs(MAX))]
2939 or ~[-INF + 1, min (abs(MIN), abs(MAX))] when
2940 flag_wrapv is set and the original anti-range doesn't include
2941 TYPE_MIN_VALUE, remember -TYPE_MIN_VALUE = TYPE_MIN_VALUE. */
2942 if (TYPE_OVERFLOW_WRAPS (type))
2944 tree type_min_value = TYPE_MIN_VALUE (type);
2946 min = (vr0.min != type_min_value
2947 ? int_const_binop (PLUS_EXPR, type_min_value,
2948 integer_one_node, 0)
2953 if (overflow_infinity_range_p (&vr0))
2954 min = negative_overflow_infinity (type);
2956 min = TYPE_MIN_VALUE (type);
2961 /* All else has failed, so create the range [0, INF], even for
2962 flag_wrapv since TYPE_MIN_VALUE is in the original
2964 vr0.type = VR_RANGE;
2965 min = build_int_cst (type, 0);
2966 if (needs_overflow_infinity (type))
2968 if (supports_overflow_infinity (type))
2969 max = positive_overflow_infinity (type);
2972 set_value_range_to_varying (vr);
2977 max = TYPE_MAX_VALUE (type);
2981 /* If the range contains zero then we know that the minimum value in the
2982 range will be zero. */
2983 else if (range_includes_zero_p (&vr0))
2987 min = build_int_cst (type, 0);
2991 /* If the range was reversed, swap MIN and MAX. */
3002 /* Otherwise, operate on each end of the range. */
3003 min = fold_unary_to_constant (code, type, vr0.min);
3004 max = fold_unary_to_constant (code, type, vr0.max);
3006 if (needs_overflow_infinity (type))
3008 gcc_assert (code != NEGATE_EXPR && code != ABS_EXPR);
3010 /* If both sides have overflowed, we don't know
3012 if ((is_overflow_infinity (vr0.min)
3013 || TREE_OVERFLOW (min))
3014 && (is_overflow_infinity (vr0.max)
3015 || TREE_OVERFLOW (max)))
3017 set_value_range_to_varying (vr);
3021 if (is_overflow_infinity (vr0.min))
3023 else if (TREE_OVERFLOW (min))
3025 if (supports_overflow_infinity (type))
3026 min = (tree_int_cst_sgn (min) >= 0
3027 ? positive_overflow_infinity (TREE_TYPE (min))
3028 : negative_overflow_infinity (TREE_TYPE (min)));
3031 set_value_range_to_varying (vr);
3036 if (is_overflow_infinity (vr0.max))
3038 else if (TREE_OVERFLOW (max))
3040 if (supports_overflow_infinity (type))
3041 max = (tree_int_cst_sgn (max) >= 0
3042 ? positive_overflow_infinity (TREE_TYPE (max))
3043 : negative_overflow_infinity (TREE_TYPE (max)));
3046 set_value_range_to_varying (vr);
3053 cmp = compare_values (min, max);
3054 if (cmp == -2 || cmp == 1)
3056 /* If the new range has its limits swapped around (MIN > MAX),
3057 then the operation caused one of them to wrap around, mark
3058 the new range VARYING. */
3059 set_value_range_to_varying (vr);
3062 set_value_range (vr, vr0.type, min, max, NULL);
3066 /* Extract range information from a conditional expression EXPR based on
3067 the ranges of each of its operands and the expression code. */
3070 extract_range_from_cond_expr (value_range_t *vr, tree expr)
3073 value_range_t vr0 = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
3074 value_range_t vr1 = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
3076 /* Get value ranges for each operand. For constant operands, create
3077 a new value range with the operand to simplify processing. */
3078 op0 = COND_EXPR_THEN (expr);
3079 if (TREE_CODE (op0) == SSA_NAME)
3080 vr0 = *(get_value_range (op0));
3081 else if (is_gimple_min_invariant (op0))
3082 set_value_range_to_value (&vr0, op0, NULL);
3084 set_value_range_to_varying (&vr0);
3086 op1 = COND_EXPR_ELSE (expr);
3087 if (TREE_CODE (op1) == SSA_NAME)
3088 vr1 = *(get_value_range (op1));
3089 else if (is_gimple_min_invariant (op1))
3090 set_value_range_to_value (&vr1, op1, NULL);
3092 set_value_range_to_varying (&vr1);
3094 /* The resulting value range is the union of the operand ranges */
3095 vrp_meet (&vr0, &vr1);
3096 copy_value_range (vr, &vr0);
3100 /* Extract range information from a comparison expression EXPR based
3101 on the range of its operand and the expression code. */
3104 extract_range_from_comparison (value_range_t *vr, enum tree_code code,
3105 tree type, tree op0, tree op1)
3110 val = vrp_evaluate_conditional_warnv_with_ops (code, op0, op1, false, &sop,
3113 /* A disadvantage of using a special infinity as an overflow
3114 representation is that we lose the ability to record overflow
3115 when we don't have an infinity. So we have to ignore a result
3116 which relies on overflow. */
3118 if (val && !is_overflow_infinity (val) && !sop)
3120 /* Since this expression was found on the RHS of an assignment,
3121 its type may be different from _Bool. Convert VAL to EXPR's
3123 val = fold_convert (type, val);
3124 if (is_gimple_min_invariant (val))
3125 set_value_range_to_value (vr, val, vr->equiv);
3127 set_value_range (vr, VR_RANGE, val, val, vr->equiv);
3130 /* The result of a comparison is always true or false. */
3131 set_value_range_to_truthvalue (vr, type);
3134 /* Try to derive a nonnegative or nonzero range out of STMT relying
3135 primarily on generic routines in fold in conjunction with range data.
3136 Store the result in *VR */
3139 extract_range_basic (value_range_t *vr, gimple stmt)
3142 tree type = gimple_expr_type (stmt);
3144 if (INTEGRAL_TYPE_P (type)
3145 && gimple_stmt_nonnegative_warnv_p (stmt, &sop))
3146 set_value_range_to_nonnegative (vr, type,
3147 sop || stmt_overflow_infinity (stmt));
3148 else if (vrp_stmt_computes_nonzero (stmt, &sop)
3150 set_value_range_to_nonnull (vr, type);
3152 set_value_range_to_varying (vr);
3156 /* Try to compute a useful range out of assignment STMT and store it
3160 extract_range_from_assignment (value_range_t *vr, gimple stmt)
3162 enum tree_code code = gimple_assign_rhs_code (stmt);
3164 if (code == ASSERT_EXPR)
3165 extract_range_from_assert (vr, gimple_assign_rhs1 (stmt));
3166 else if (code == SSA_NAME)
3167 extract_range_from_ssa_name (vr, gimple_assign_rhs1 (stmt));
3168 else if (TREE_CODE_CLASS (code) == tcc_binary
3169 || code == TRUTH_AND_EXPR
3170 || code == TRUTH_OR_EXPR
3171 || code == TRUTH_XOR_EXPR)
3172 extract_range_from_binary_expr (vr, gimple_assign_rhs_code (stmt),
3173 gimple_expr_type (stmt),
3174 gimple_assign_rhs1 (stmt),
3175 gimple_assign_rhs2 (stmt));
3176 else if (TREE_CODE_CLASS (code) == tcc_unary)
3177 extract_range_from_unary_expr (vr, gimple_assign_rhs_code (stmt),
3178 gimple_expr_type (stmt),
3179 gimple_assign_rhs1 (stmt));
3180 else if (code == COND_EXPR)
3181 extract_range_from_cond_expr (vr, gimple_assign_rhs1 (stmt));
3182 else if (TREE_CODE_CLASS (code) == tcc_comparison)
3183 extract_range_from_comparison (vr, gimple_assign_rhs_code (stmt),
3184 gimple_expr_type (stmt),
3185 gimple_assign_rhs1 (stmt),
3186 gimple_assign_rhs2 (stmt));
3187 else if (get_gimple_rhs_class (code) == GIMPLE_SINGLE_RHS
3188 && is_gimple_min_invariant (gimple_assign_rhs1 (stmt)))
3189 set_value_range_to_value (vr, gimple_assign_rhs1 (stmt), NULL);
3191 set_value_range_to_varying (vr);
3193 if (vr->type == VR_VARYING)
3194 extract_range_basic (vr, stmt);
3197 /* Given a range VR, a LOOP and a variable VAR, determine whether it
3198 would be profitable to adjust VR using scalar evolution information
3199 for VAR. If so, update VR with the new limits. */
3202 adjust_range_with_scev (value_range_t *vr, struct loop *loop,
3203 gimple stmt, tree var)
3205 tree init, step, chrec, tmin, tmax, min, max, type, tem;
3206 enum ev_direction dir;
3208 /* TODO. Don't adjust anti-ranges. An anti-range may provide
3209 better opportunities than a regular range, but I'm not sure. */
3210 if (vr->type == VR_ANTI_RANGE)
3213 chrec = instantiate_parameters (loop, analyze_scalar_evolution (loop, var));
3215 /* Like in PR19590, scev can return a constant function. */
3216 if (is_gimple_min_invariant (chrec))
3218 set_value_range_to_value (vr, chrec, vr->equiv);
3222 if (TREE_CODE (chrec) != POLYNOMIAL_CHREC)
3225 init = initial_condition_in_loop_num (chrec, loop->num);
3226 tem = op_with_constant_singleton_value_range (init);
3229 step = evolution_part_in_loop_num (chrec, loop->num);
3230 tem = op_with_constant_singleton_value_range (step);
3234 /* If STEP is symbolic, we can't know whether INIT will be the
3235 minimum or maximum value in the range. Also, unless INIT is
3236 a simple expression, compare_values and possibly other functions
3237 in tree-vrp won't be able to handle it. */
3238 if (step == NULL_TREE
3239 || !is_gimple_min_invariant (step)
3240 || !valid_value_p (init))
3243 dir = scev_direction (chrec);
3244 if (/* Do not adjust ranges if we do not know whether the iv increases
3245 or decreases, ... */
3246 dir == EV_DIR_UNKNOWN
3247 /* ... or if it may wrap. */
3248 || scev_probably_wraps_p (init, step, stmt, get_chrec_loop (chrec),
3252 /* We use TYPE_MIN_VALUE and TYPE_MAX_VALUE here instead of
3253 negative_overflow_infinity and positive_overflow_infinity,
3254 because we have concluded that the loop probably does not
3257 type = TREE_TYPE (var);
3258 if (POINTER_TYPE_P (type) || !TYPE_MIN_VALUE (type))
3259 tmin = lower_bound_in_type (type, type);
3261 tmin = TYPE_MIN_VALUE (type);
3262 if (POINTER_TYPE_P (type) || !TYPE_MAX_VALUE (type))
3263 tmax = upper_bound_in_type (type, type);
3265 tmax = TYPE_MAX_VALUE (type);
3267 if (vr->type == VR_VARYING || vr->type == VR_UNDEFINED)
3272 /* For VARYING or UNDEFINED ranges, just about anything we get
3273 from scalar evolutions should be better. */
3275 if (dir == EV_DIR_DECREASES)
3280 /* If we would create an invalid range, then just assume we
3281 know absolutely nothing. This may be over-conservative,
3282 but it's clearly safe, and should happen only in unreachable
3283 parts of code, or for invalid programs. */
3284 if (compare_values (min, max) == 1)
3287 set_value_range (vr, VR_RANGE, min, max, vr->equiv);
3289 else if (vr->type == VR_RANGE)
3294 if (dir == EV_DIR_DECREASES)
3296 /* INIT is the maximum value. If INIT is lower than VR->MAX
3297 but no smaller than VR->MIN, set VR->MAX to INIT. */
3298 if (compare_values (init, max) == -1)
3302 /* If we just created an invalid range with the minimum
3303 greater than the maximum, we fail conservatively.
3304 This should happen only in unreachable
3305 parts of code, or for invalid programs. */
3306 if (compare_values (min, max) == 1)
3310 /* According to the loop information, the variable does not
3311 overflow. If we think it does, probably because of an
3312 overflow due to arithmetic on a different INF value,
3314 if (is_negative_overflow_infinity (min))
3319 /* If INIT is bigger than VR->MIN, set VR->MIN to INIT. */
3320 if (compare_values (init, min) == 1)
3324 /* Again, avoid creating invalid range by failing. */
3325 if (compare_values (min, max) == 1)
3329 if (is_positive_overflow_infinity (max))
3333 set_value_range (vr, VR_RANGE, min, max, vr->equiv);
3337 /* Return true if VAR may overflow at STMT. This checks any available
3338 loop information to see if we can determine that VAR does not
3342 vrp_var_may_overflow (tree var, gimple stmt)
3345 tree chrec, init, step;
3347 if (current_loops == NULL)
3350 l = loop_containing_stmt (stmt);
3355 chrec = instantiate_parameters (l, analyze_scalar_evolution (l, var));
3356 if (TREE_CODE (chrec) != POLYNOMIAL_CHREC)
3359 init = initial_condition_in_loop_num (chrec, l->num);
3360 step = evolution_part_in_loop_num (chrec, l->num);
3362 if (step == NULL_TREE
3363 || !is_gimple_min_invariant (step)
3364 || !valid_value_p (init))
3367 /* If we get here, we know something useful about VAR based on the
3368 loop information. If it wraps, it may overflow. */
3370 if (scev_probably_wraps_p (init, step, stmt, get_chrec_loop (chrec),
3374 if (dump_file && (dump_flags & TDF_DETAILS) != 0)
3376 print_generic_expr (dump_file, var, 0);
3377 fprintf (dump_file, ": loop information indicates does not overflow\n");
3384 /* Given two numeric value ranges VR0, VR1 and a comparison code COMP:
3386 - Return BOOLEAN_TRUE_NODE if VR0 COMP VR1 always returns true for
3387 all the values in the ranges.
3389 - Return BOOLEAN_FALSE_NODE if the comparison always returns false.
3391 - Return NULL_TREE if it is not always possible to determine the
3392 value of the comparison.
3394 Also set *STRICT_OVERFLOW_P to indicate whether a range with an
3395 overflow infinity was used in the test. */
3399 compare_ranges (enum tree_code comp, value_range_t *vr0, value_range_t *vr1,
3400 bool *strict_overflow_p)
3402 /* VARYING or UNDEFINED ranges cannot be compared. */
3403 if (vr0->type == VR_VARYING
3404 || vr0->type == VR_UNDEFINED
3405 || vr1->type == VR_VARYING
3406 || vr1->type == VR_UNDEFINED)
3409 /* Anti-ranges need to be handled separately. */
3410 if (vr0->type == VR_ANTI_RANGE || vr1->type == VR_ANTI_RANGE)
3412 /* If both are anti-ranges, then we cannot compute any
3414 if (vr0->type == VR_ANTI_RANGE && vr1->type == VR_ANTI_RANGE)
3417 /* These comparisons are never statically computable. */
3424 /* Equality can be computed only between a range and an
3425 anti-range. ~[VAL1, VAL2] == [VAL1, VAL2] is always false. */
3426 if (vr0->type == VR_RANGE)
3428 /* To simplify processing, make VR0 the anti-range. */
3429 value_range_t *tmp = vr0;
3434 gcc_assert (comp == NE_EXPR || comp == EQ_EXPR);
3436 if (compare_values_warnv (vr0->min, vr1->min, strict_overflow_p) == 0
3437 && compare_values_warnv (vr0->max, vr1->max, strict_overflow_p) == 0)
3438 return (comp == NE_EXPR) ? boolean_true_node : boolean_false_node;
3443 if (!usable_range_p (vr0, strict_overflow_p)
3444 || !usable_range_p (vr1, strict_overflow_p))
3447 /* Simplify processing. If COMP is GT_EXPR or GE_EXPR, switch the
3448 operands around and change the comparison code. */
3449 if (comp == GT_EXPR || comp == GE_EXPR)
3452 comp = (comp == GT_EXPR) ? LT_EXPR : LE_EXPR;
3458 if (comp == EQ_EXPR)
3460 /* Equality may only be computed if both ranges represent
3461 exactly one value. */
3462 if (compare_values_warnv (vr0->min, vr0->max, strict_overflow_p) == 0
3463 && compare_values_warnv (vr1->min, vr1->max, strict_overflow_p) == 0)
3465 int cmp_min = compare_values_warnv (vr0->min, vr1->min,
3467 int cmp_max = compare_values_warnv (vr0->max, vr1->max,
3469 if (cmp_min == 0 && cmp_max == 0)
3470 return boolean_true_node;
3471 else if (cmp_min != -2 && cmp_max != -2)
3472 return boolean_false_node;
3474 /* If [V0_MIN, V1_MAX] < [V1_MIN, V1_MAX] then V0 != V1. */
3475 else if (compare_values_warnv (vr0->min, vr1->max,
3476 strict_overflow_p) == 1
3477 || compare_values_warnv (vr1->min, vr0->max,
3478 strict_overflow_p) == 1)
3479 return boolean_false_node;
3483 else if (comp == NE_EXPR)
3487 /* If VR0 is completely to the left or completely to the right
3488 of VR1, they are always different. Notice that we need to
3489 make sure that both comparisons yield similar results to
3490 avoid comparing values that cannot be compared at
3492 cmp1 = compare_values_warnv (vr0->max, vr1->min, strict_overflow_p);
3493 cmp2 = compare_values_warnv (vr0->min, vr1->max, strict_overflow_p);
3494 if ((cmp1 == -1 && cmp2 == -1) || (cmp1 == 1 && cmp2 == 1))
3495 return boolean_true_node;
3497 /* If VR0 and VR1 represent a single value and are identical,
3499 else if (compare_values_warnv (vr0->min, vr0->max,
3500 strict_overflow_p) == 0
3501 && compare_values_warnv (vr1->min, vr1->max,
3502 strict_overflow_p) == 0
3503 && compare_values_warnv (vr0->min, vr1->min,
3504 strict_overflow_p) == 0
3505 && compare_values_warnv (vr0->max, vr1->max,
3506 strict_overflow_p) == 0)
3507 return boolean_false_node;
3509 /* Otherwise, they may or may not be different. */
3513 else if (comp == LT_EXPR || comp == LE_EXPR)
3517 /* If VR0 is to the left of VR1, return true. */
3518 tst = compare_values_warnv (vr0->max, vr1->min, strict_overflow_p);
3519 if ((comp == LT_EXPR && tst == -1)
3520 || (comp == LE_EXPR && (tst == -1 || tst == 0)))
3522 if (overflow_infinity_range_p (vr0)
3523 || overflow_infinity_range_p (vr1))
3524 *strict_overflow_p = true;
3525 return boolean_true_node;
3528 /* If VR0 is to the right of VR1, return false. */
3529 tst = compare_values_warnv (vr0->min, vr1->max, strict_overflow_p);
3530 if ((comp == LT_EXPR && (tst == 0 || tst == 1))
3531 || (comp == LE_EXPR && tst == 1))
3533 if (overflow_infinity_range_p (vr0)
3534 || overflow_infinity_range_p (vr1))
3535 *strict_overflow_p = true;
3536 return boolean_false_node;
3539 /* Otherwise, we don't know. */
3547 /* Given a value range VR, a value VAL and a comparison code COMP, return
3548 BOOLEAN_TRUE_NODE if VR COMP VAL always returns true for all the
3549 values in VR. Return BOOLEAN_FALSE_NODE if the comparison
3550 always returns false. Return NULL_TREE if it is not always
3551 possible to determine the value of the comparison. Also set
3552 *STRICT_OVERFLOW_P to indicate whether a range with an overflow
3553 infinity was used in the test. */
3556 compare_range_with_value (enum tree_code comp, value_range_t *vr, tree val,
3557 bool *strict_overflow_p)
3559 if (vr->type == VR_VARYING || vr->type == VR_UNDEFINED)
3562 /* Anti-ranges need to be handled separately. */
3563 if (vr->type == VR_ANTI_RANGE)
3565 /* For anti-ranges, the only predicates that we can compute at
3566 compile time are equality and inequality. */
3573 /* ~[VAL_1, VAL_2] OP VAL is known if VAL_1 <= VAL <= VAL_2. */
3574 if (value_inside_range (val, vr) == 1)
3575 return (comp == NE_EXPR) ? boolean_true_node : boolean_false_node;
3580 if (!usable_range_p (vr, strict_overflow_p))
3583 if (comp == EQ_EXPR)
3585 /* EQ_EXPR may only be computed if VR represents exactly
3587 if (compare_values_warnv (vr->min, vr->max, strict_overflow_p) == 0)
3589 int cmp = compare_values_warnv (vr->min, val, strict_overflow_p);
3591 return boolean_true_node;
3592 else if (cmp == -1 || cmp == 1 || cmp == 2)
3593 return boolean_false_node;
3595 else if (compare_values_warnv (val, vr->min, strict_overflow_p) == -1
3596 || compare_values_warnv (vr->max, val, strict_overflow_p) == -1)
3597 return boolean_false_node;
3601 else if (comp == NE_EXPR)
3603 /* If VAL is not inside VR, then they are always different. */
3604 if (compare_values_warnv (vr->max, val, strict_overflow_p) == -1
3605 || compare_values_warnv (vr->min, val, strict_overflow_p) == 1)
3606 return boolean_true_node;
3608 /* If VR represents exactly one value equal to VAL, then return
3610 if (compare_values_warnv (vr->min, vr->max, strict_overflow_p) == 0
3611 && compare_values_warnv (vr->min, val, strict_overflow_p) == 0)
3612 return boolean_false_node;
3614 /* Otherwise, they may or may not be different. */
3617 else if (comp == LT_EXPR || comp == LE_EXPR)
3621 /* If VR is to the left of VAL, return true. */
3622 tst = compare_values_warnv (vr->max, val, strict_overflow_p);
3623 if ((comp == LT_EXPR && tst == -1)
3624 || (comp == LE_EXPR && (tst == -1 || tst == 0)))
3626 if (overflow_infinity_range_p (vr))
3627 *strict_overflow_p = true;
3628 return boolean_true_node;
3631 /* If VR is to the right of VAL, return false. */
3632 tst = compare_values_warnv (vr->min, val, strict_overflow_p);
3633 if ((comp == LT_EXPR && (tst == 0 || tst == 1))
3634 || (comp == LE_EXPR && tst == 1))
3636 if (overflow_infinity_range_p (vr))
3637 *strict_overflow_p = true;
3638 return boolean_false_node;
3641 /* Otherwise, we don't know. */
3644 else if (comp == GT_EXPR || comp == GE_EXPR)
3648 /* If VR is to the right of VAL, return true. */
3649 tst = compare_values_warnv (vr->min, val, strict_overflow_p);
3650 if ((comp == GT_EXPR && tst == 1)
3651 || (comp == GE_EXPR && (tst == 0 || tst == 1)))
3653 if (overflow_infinity_range_p (vr))
3654 *strict_overflow_p = true;
3655 return boolean_true_node;
3658 /* If VR is to the left of VAL, return false. */
3659 tst = compare_values_warnv (vr->max, val, strict_overflow_p);
3660 if ((comp == GT_EXPR && (tst == -1 || tst == 0))
3661 || (comp == GE_EXPR && tst == -1))
3663 if (overflow_infinity_range_p (vr))
3664 *strict_overflow_p = true;
3665 return boolean_false_node;
3668 /* Otherwise, we don't know. */
3676 /* Debugging dumps. */
3678 void dump_value_range (FILE *, value_range_t *);
3679 void debug_value_range (value_range_t *);
3680 void dump_all_value_ranges (FILE *);
3681 void debug_all_value_ranges (void);
3682 void dump_vr_equiv (FILE *, bitmap);
3683 void debug_vr_equiv (bitmap);
3686 /* Dump value range VR to FILE. */
3689 dump_value_range (FILE *file, value_range_t *vr)
3692 fprintf (file, "[]");
3693 else if (vr->type == VR_UNDEFINED)
3694 fprintf (file, "UNDEFINED");
3695 else if (vr->type == VR_RANGE || vr->type == VR_ANTI_RANGE)
3697 tree type = TREE_TYPE (vr->min);
3699 fprintf (file, "%s[", (vr->type == VR_ANTI_RANGE) ? "~" : "");
3701 if (is_negative_overflow_infinity (vr->min))
3702 fprintf (file, "-INF(OVF)");
3703 else if (INTEGRAL_TYPE_P (type)
3704 && !TYPE_UNSIGNED (type)
3705 && vrp_val_is_min (vr->min))
3706 fprintf (file, "-INF");
3708 print_generic_expr (file, vr->min, 0);
3710 fprintf (file, ", ");
3712 if (is_positive_overflow_infinity (vr->max))
3713 fprintf (file, "+INF(OVF)");
3714 else if (INTEGRAL_TYPE_P (type)
3715 && vrp_val_is_max (vr->max))
3716 fprintf (file, "+INF");
3718 print_generic_expr (file, vr->max, 0);
3720 fprintf (file, "]");
3727 fprintf (file, " EQUIVALENCES: { ");
3729 EXECUTE_IF_SET_IN_BITMAP (vr->equiv, 0, i, bi)
3731 print_generic_expr (file, ssa_name (i), 0);
3732 fprintf (file, " ");
3736 fprintf (file, "} (%u elements)", c);
3739 else if (vr->type == VR_VARYING)
3740 fprintf (file, "VARYING");
3742 fprintf (file, "INVALID RANGE");
3746 /* Dump value range VR to stderr. */
3749 debug_value_range (value_range_t *vr)
3751 dump_value_range (stderr, vr);
3752 fprintf (stderr, "\n");
3756 /* Dump value ranges of all SSA_NAMEs to FILE. */
3759 dump_all_value_ranges (FILE *file)
3763 for (i = 0; i < num_ssa_names; i++)
3767 print_generic_expr (file, ssa_name (i), 0);
3768 fprintf (file, ": ");
3769 dump_value_range (file, vr_value[i]);
3770 fprintf (file, "\n");
3774 fprintf (file, "\n");
3778 /* Dump all value ranges to stderr. */
3781 debug_all_value_ranges (void)
3783 dump_all_value_ranges (stderr);
3787 /* Given a COND_EXPR COND of the form 'V OP W', and an SSA name V,
3788 create a new SSA name N and return the assertion assignment
3789 'V = ASSERT_EXPR <V, V OP W>'. */
3792 build_assert_expr_for (tree cond, tree v)
3797 gcc_assert (TREE_CODE (v) == SSA_NAME);
3798 n = duplicate_ssa_name (v, NULL);
3800 if (COMPARISON_CLASS_P (cond))
3802 tree a = build2 (ASSERT_EXPR, TREE_TYPE (v), v, cond);
3803 assertion = gimple_build_assign (n, a);
3805 else if (TREE_CODE (cond) == TRUTH_NOT_EXPR)
3807 /* Given !V, build the assignment N = false. */
3808 tree op0 = TREE_OPERAND (cond, 0);
3809 gcc_assert (op0 == v);
3810 assertion = gimple_build_assign (n, boolean_false_node);
3812 else if (TREE_CODE (cond) == SSA_NAME)
3814 /* Given V, build the assignment N = true. */
3815 gcc_assert (v == cond);
3816 assertion = gimple_build_assign (n, boolean_true_node);
3821 SSA_NAME_DEF_STMT (n) = assertion;
3823 /* The new ASSERT_EXPR, creates a new SSA name that replaces the
3824 operand of the ASSERT_EXPR. Register the new name and the old one
3825 in the replacement table so that we can fix the SSA web after
3826 adding all the ASSERT_EXPRs. */
3827 register_new_name_mapping (n, v);
3833 /* Return false if EXPR is a predicate expression involving floating
3837 fp_predicate (gimple stmt)
3839 GIMPLE_CHECK (stmt, GIMPLE_COND);
3841 return FLOAT_TYPE_P (TREE_TYPE (gimple_cond_lhs (stmt)));
3845 /* If the range of values taken by OP can be inferred after STMT executes,
3846 return the comparison code (COMP_CODE_P) and value (VAL_P) that
3847 describes the inferred range. Return true if a range could be
3851 infer_value_range (gimple stmt, tree op, enum tree_code *comp_code_p, tree *val_p)
3854 *comp_code_p = ERROR_MARK;
3856 /* Do not attempt to infer anything in names that flow through
3858 if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (op))
3861 /* Similarly, don't infer anything from statements that may throw
3863 if (stmt_could_throw_p (stmt))
3866 /* If STMT is the last statement of a basic block with no
3867 successors, there is no point inferring anything about any of its
3868 operands. We would not be able to find a proper insertion point
3869 for the assertion, anyway. */
3870 if (stmt_ends_bb_p (stmt) && EDGE_COUNT (gimple_bb (stmt)->succs) == 0)
3873 /* We can only assume that a pointer dereference will yield
3874 non-NULL if -fdelete-null-pointer-checks is enabled. */
3875 if (flag_delete_null_pointer_checks
3876 && POINTER_TYPE_P (TREE_TYPE (op))
3877 && gimple_code (stmt) != GIMPLE_ASM)
3879 unsigned num_uses, num_loads, num_stores;
3881 count_uses_and_derefs (op, stmt, &num_uses, &num_loads, &num_stores);
3882 if (num_loads + num_stores > 0)
3884 *val_p = build_int_cst (TREE_TYPE (op), 0);
3885 *comp_code_p = NE_EXPR;
3894 void dump_asserts_for (FILE *, tree);
3895 void debug_asserts_for (tree);
3896 void dump_all_asserts (FILE *);
3897 void debug_all_asserts (void);
3899 /* Dump all the registered assertions for NAME to FILE. */
3902 dump_asserts_for (FILE *file, tree name)
3906 fprintf (file, "Assertions to be inserted for ");
3907 print_generic_expr (file, name, 0);
3908 fprintf (file, "\n");
3910 loc = asserts_for[SSA_NAME_VERSION (name)];
3913 fprintf (file, "\t");
3914 print_gimple_stmt (file, gsi_stmt (loc->si), 0, 0);
3915 fprintf (file, "\n\tBB #%d", loc->bb->index);
3918 fprintf (file, "\n\tEDGE %d->%d", loc->e->src->index,
3919 loc->e->dest->index);
3920 dump_edge_info (file, loc->e, 0);
3922 fprintf (file, "\n\tPREDICATE: ");
3923 print_generic_expr (file, name, 0);
3924 fprintf (file, " %s ", tree_code_name[(int)loc->comp_code]);
3925 print_generic_expr (file, loc->val, 0);
3926 fprintf (file, "\n\n");
3930 fprintf (file, "\n");
3934 /* Dump all the registered assertions for NAME to stderr. */
3937 debug_asserts_for (tree name)
3939 dump_asserts_for (stderr, name);
3943 /* Dump all the registered assertions for all the names to FILE. */
3946 dump_all_asserts (FILE *file)
3951 fprintf (file, "\nASSERT_EXPRs to be inserted\n\n");
3952 EXECUTE_IF_SET_IN_BITMAP (need_assert_for, 0, i, bi)
3953 dump_asserts_for (file, ssa_name (i));
3954 fprintf (file, "\n");
3958 /* Dump all the registered assertions for all the names to stderr. */
3961 debug_all_asserts (void)
3963 dump_all_asserts (stderr);
3967 /* If NAME doesn't have an ASSERT_EXPR registered for asserting
3968 'EXPR COMP_CODE VAL' at a location that dominates block BB or
3969 E->DEST, then register this location as a possible insertion point
3970 for ASSERT_EXPR <NAME, EXPR COMP_CODE VAL>.
3972 BB, E and SI provide the exact insertion point for the new
3973 ASSERT_EXPR. If BB is NULL, then the ASSERT_EXPR is to be inserted
3974 on edge E. Otherwise, if E is NULL, the ASSERT_EXPR is inserted on
3975 BB. If SI points to a COND_EXPR or a SWITCH_EXPR statement, then E
3976 must not be NULL. */
3979 register_new_assert_for (tree name, tree expr,
3980 enum tree_code comp_code,
3984 gimple_stmt_iterator si)
3986 assert_locus_t n, loc, last_loc;
3987 basic_block dest_bb;
3989 #if defined ENABLE_CHECKING
3990 gcc_assert (bb == NULL || e == NULL);
3993 gcc_assert (gimple_code (gsi_stmt (si)) != GIMPLE_COND
3994 && gimple_code (gsi_stmt (si)) != GIMPLE_SWITCH);
3997 /* Never build an assert comparing against an integer constant with
3998 TREE_OVERFLOW set. This confuses our undefined overflow warning
4000 if (TREE_CODE (val) == INTEGER_CST
4001 && TREE_OVERFLOW (val))
4002 val = build_int_cst_wide (TREE_TYPE (val),
4003 TREE_INT_CST_LOW (val), TREE_INT_CST_HIGH (val));
4005 /* The new assertion A will be inserted at BB or E. We need to
4006 determine if the new location is dominated by a previously
4007 registered location for A. If we are doing an edge insertion,
4008 assume that A will be inserted at E->DEST. Note that this is not
4011 If E is a critical edge, it will be split. But even if E is
4012 split, the new block will dominate the same set of blocks that
4015 The reverse, however, is not true, blocks dominated by E->DEST
4016 will not be dominated by the new block created to split E. So,
4017 if the insertion location is on a critical edge, we will not use
4018 the new location to move another assertion previously registered
4019 at a block dominated by E->DEST. */
4020 dest_bb = (bb) ? bb : e->dest;
4022 /* If NAME already has an ASSERT_EXPR registered for COMP_CODE and
4023 VAL at a block dominating DEST_BB, then we don't need to insert a new
4024 one. Similarly, if the same assertion already exists at a block
4025 dominated by DEST_BB and the new location is not on a critical
4026 edge, then update the existing location for the assertion (i.e.,
4027 move the assertion up in the dominance tree).
4029 Note, this is implemented as a simple linked list because there
4030 should not be more than a handful of assertions registered per
4031 name. If this becomes a performance problem, a table hashed by
4032 COMP_CODE and VAL could be implemented. */
4033 loc = asserts_for[SSA_NAME_VERSION (name)];
4037 if (loc->comp_code == comp_code
4039 || operand_equal_p (loc->val, val, 0))
4040 && (loc->expr == expr
4041 || operand_equal_p (loc->expr, expr, 0)))
4043 /* If the assertion NAME COMP_CODE VAL has already been
4044 registered at a basic block that dominates DEST_BB, then
4045 we don't need to insert the same assertion again. Note
4046 that we don't check strict dominance here to avoid
4047 replicating the same assertion inside the same basic
4048 block more than once (e.g., when a pointer is
4049 dereferenced several times inside a block).
4051 An exception to this rule are edge insertions. If the
4052 new assertion is to be inserted on edge E, then it will
4053 dominate all the other insertions that we may want to
4054 insert in DEST_BB. So, if we are doing an edge
4055 insertion, don't do this dominance check. */
4057 && dominated_by_p (CDI_DOMINATORS, dest_bb, loc->bb))
4060 /* Otherwise, if E is not a critical edge and DEST_BB
4061 dominates the existing location for the assertion, move
4062 the assertion up in the dominance tree by updating its
4063 location information. */
4064 if ((e == NULL || !EDGE_CRITICAL_P (e))
4065 && dominated_by_p (CDI_DOMINATORS, loc->bb, dest_bb))
4074 /* Update the last node of the list and move to the next one. */
4079 /* If we didn't find an assertion already registered for
4080 NAME COMP_CODE VAL, add a new one at the end of the list of
4081 assertions associated with NAME. */
4082 n = XNEW (struct assert_locus_d);
4086 n->comp_code = comp_code;
4094 asserts_for[SSA_NAME_VERSION (name)] = n;
4096 bitmap_set_bit (need_assert_for, SSA_NAME_VERSION (name));
4099 /* (COND_OP0 COND_CODE COND_OP1) is a predicate which uses NAME.
4100 Extract a suitable test code and value and store them into *CODE_P and
4101 *VAL_P so the predicate is normalized to NAME *CODE_P *VAL_P.
4103 If no extraction was possible, return FALSE, otherwise return TRUE.
4105 If INVERT is true, then we invert the result stored into *CODE_P. */
4108 extract_code_and_val_from_cond_with_ops (tree name, enum tree_code cond_code,
4109 tree cond_op0, tree cond_op1,
4110 bool invert, enum tree_code *code_p,
4113 enum tree_code comp_code;
4116 /* Otherwise, we have a comparison of the form NAME COMP VAL
4117 or VAL COMP NAME. */
4118 if (name == cond_op1)
4120 /* If the predicate is of the form VAL COMP NAME, flip
4121 COMP around because we need to register NAME as the
4122 first operand in the predicate. */
4123 comp_code = swap_tree_comparison (cond_code);
4128 /* The comparison is of the form NAME COMP VAL, so the
4129 comparison code remains unchanged. */
4130 comp_code = cond_code;
4134 /* Invert the comparison code as necessary. */
4136 comp_code = invert_tree_comparison (comp_code, 0);
4138 /* VRP does not handle float types. */
4139 if (SCALAR_FLOAT_TYPE_P (TREE_TYPE (val)))
4142 /* Do not register always-false predicates.
4143 FIXME: this works around a limitation in fold() when dealing with
4144 enumerations. Given 'enum { N1, N2 } x;', fold will not
4145 fold 'if (x > N2)' to 'if (0)'. */
4146 if ((comp_code == GT_EXPR || comp_code == LT_EXPR)
4147 && INTEGRAL_TYPE_P (TREE_TYPE (val)))
4149 tree min = TYPE_MIN_VALUE (TREE_TYPE (val));
4150 tree max = TYPE_MAX_VALUE (TREE_TYPE (val));
4152 if (comp_code == GT_EXPR
4154 || compare_values (val, max) == 0))
4157 if (comp_code == LT_EXPR
4159 || compare_values (val, min) == 0))
4162 *code_p = comp_code;
4167 /* Try to register an edge assertion for SSA name NAME on edge E for
4168 the condition COND contributing to the conditional jump pointed to by BSI.
4169 Invert the condition COND if INVERT is true.
4170 Return true if an assertion for NAME could be registered. */
4173 register_edge_assert_for_2 (tree name, edge e, gimple_stmt_iterator bsi,
4174 enum tree_code cond_code,
4175 tree cond_op0, tree cond_op1, bool invert)
4178 enum tree_code comp_code;
4179 bool retval = false;
4181 if (!extract_code_and_val_from_cond_with_ops (name, cond_code,
4184 invert, &comp_code, &val))
4187 /* Only register an ASSERT_EXPR if NAME was found in the sub-graph
4188 reachable from E. */
4189 if (live_on_edge (e, name)
4190 && !has_single_use (name))
4192 register_new_assert_for (name, name, comp_code, val, NULL, e, bsi);
4196 /* In the case of NAME <= CST and NAME being defined as
4197 NAME = (unsigned) NAME2 + CST2 we can assert NAME2 >= -CST2
4198 and NAME2 <= CST - CST2. We can do the same for NAME > CST.
4199 This catches range and anti-range tests. */
4200 if ((comp_code == LE_EXPR
4201 || comp_code == GT_EXPR)
4202 && TREE_CODE (val) == INTEGER_CST
4203 && TYPE_UNSIGNED (TREE_TYPE (val)))
4205 gimple def_stmt = SSA_NAME_DEF_STMT (name);
4206 tree cst2 = NULL_TREE, name2 = NULL_TREE, name3 = NULL_TREE;
4208 /* Extract CST2 from the (optional) addition. */
4209 if (is_gimple_assign (def_stmt)
4210 && gimple_assign_rhs_code (def_stmt) == PLUS_EXPR)
4212 name2 = gimple_assign_rhs1 (def_stmt);
4213 cst2 = gimple_assign_rhs2 (def_stmt);
4214 if (TREE_CODE (name2) == SSA_NAME
4215 && TREE_CODE (cst2) == INTEGER_CST)
4216 def_stmt = SSA_NAME_DEF_STMT (name2);
4219 /* Extract NAME2 from the (optional) sign-changing cast. */
4220 if (gimple_assign_cast_p (def_stmt))
4222 if (CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (def_stmt))
4223 && ! TYPE_UNSIGNED (TREE_TYPE (gimple_assign_rhs1 (def_stmt)))
4224 && (TYPE_PRECISION (gimple_expr_type (def_stmt))
4225 == TYPE_PRECISION (TREE_TYPE (gimple_assign_rhs1 (def_stmt)))))
4226 name3 = gimple_assign_rhs1 (def_stmt);
4229 /* If name3 is used later, create an ASSERT_EXPR for it. */
4230 if (name3 != NULL_TREE
4231 && TREE_CODE (name3) == SSA_NAME
4232 && (cst2 == NULL_TREE
4233 || TREE_CODE (cst2) == INTEGER_CST)
4234 && INTEGRAL_TYPE_P (TREE_TYPE (name3))
4235 && live_on_edge (e, name3)
4236 && !has_single_use (name3))
4240 /* Build an expression for the range test. */
4241 tmp = build1 (NOP_EXPR, TREE_TYPE (name), name3);
4242 if (cst2 != NULL_TREE)
4243 tmp = build2 (PLUS_EXPR, TREE_TYPE (name), tmp, cst2);
4247 fprintf (dump_file, "Adding assert for ");
4248 print_generic_expr (dump_file, name3, 0);
4249 fprintf (dump_file, " from ");
4250 print_generic_expr (dump_file, tmp, 0);
4251 fprintf (dump_file, "\n");
4254 register_new_assert_for (name3, tmp, comp_code, val, NULL, e, bsi);
4259 /* If name2 is used later, create an ASSERT_EXPR for it. */
4260 if (name2 != NULL_TREE
4261 && TREE_CODE (name2) == SSA_NAME
4262 && TREE_CODE (cst2) == INTEGER_CST
4263 && INTEGRAL_TYPE_P (TREE_TYPE (name2))
4264 && live_on_edge (e, name2)
4265 && !has_single_use (name2))
4269 /* Build an expression for the range test. */
4271 if (TREE_TYPE (name) != TREE_TYPE (name2))
4272 tmp = build1 (NOP_EXPR, TREE_TYPE (name), tmp);
4273 if (cst2 != NULL_TREE)
4274 tmp = build2 (PLUS_EXPR, TREE_TYPE (name), tmp, cst2);
4278 fprintf (dump_file, "Adding assert for ");
4279 print_generic_expr (dump_file, name2, 0);
4280 fprintf (dump_file, " from ");
4281 print_generic_expr (dump_file, tmp, 0);
4282 fprintf (dump_file, "\n");
4285 register_new_assert_for (name2, tmp, comp_code, val, NULL, e, bsi);
4294 /* OP is an operand of a truth value expression which is known to have
4295 a particular value. Register any asserts for OP and for any
4296 operands in OP's defining statement.
4298 If CODE is EQ_EXPR, then we want to register OP is zero (false),
4299 if CODE is NE_EXPR, then we want to register OP is nonzero (true). */
4302 register_edge_assert_for_1 (tree op, enum tree_code code,
4303 edge e, gimple_stmt_iterator bsi)
4305 bool retval = false;
4308 enum tree_code rhs_code;
4310 /* We only care about SSA_NAMEs. */
4311 if (TREE_CODE (op) != SSA_NAME)
4314 /* We know that OP will have a zero or nonzero value. If OP is used
4315 more than once go ahead and register an assert for OP.
4317 The FOUND_IN_SUBGRAPH support is not helpful in this situation as
4318 it will always be set for OP (because OP is used in a COND_EXPR in
4320 if (!has_single_use (op))
4322 val = build_int_cst (TREE_TYPE (op), 0);
4323 register_new_assert_for (op, op, code, val, NULL, e, bsi);
4327 /* Now look at how OP is set. If it's set from a comparison,
4328 a truth operation or some bit operations, then we may be able
4329 to register information about the operands of that assignment. */
4330 op_def = SSA_NAME_DEF_STMT (op);
4331 if (gimple_code (op_def) != GIMPLE_ASSIGN)
4334 rhs_code = gimple_assign_rhs_code (op_def);
4336 if (TREE_CODE_CLASS (rhs_code) == tcc_comparison)
4338 bool invert = (code == EQ_EXPR ? true : false);
4339 tree op0 = gimple_assign_rhs1 (op_def);
4340 tree op1 = gimple_assign_rhs2 (op_def);
4342 if (TREE_CODE (op0) == SSA_NAME)
4343 retval |= register_edge_assert_for_2 (op0, e, bsi, rhs_code, op0, op1,
4345 if (TREE_CODE (op1) == SSA_NAME)
4346 retval |= register_edge_assert_for_2 (op1, e, bsi, rhs_code, op0, op1,
4349 else if ((code == NE_EXPR
4350 && (gimple_assign_rhs_code (op_def) == TRUTH_AND_EXPR
4351 || gimple_assign_rhs_code (op_def) == BIT_AND_EXPR))
4353 && (gimple_assign_rhs_code (op_def) == TRUTH_OR_EXPR
4354 || gimple_assign_rhs_code (op_def) == BIT_IOR_EXPR)))
4356 /* Recurse on each operand. */
4357 retval |= register_edge_assert_for_1 (gimple_assign_rhs1 (op_def),
4359 retval |= register_edge_assert_for_1 (gimple_assign_rhs2 (op_def),
4362 else if (gimple_assign_rhs_code (op_def) == TRUTH_NOT_EXPR)
4364 /* Recurse, flipping CODE. */
4365 code = invert_tree_comparison (code, false);
4366 retval |= register_edge_assert_for_1 (gimple_assign_rhs1 (op_def),
4369 else if (gimple_assign_rhs_code (op_def) == SSA_NAME)
4371 /* Recurse through the copy. */
4372 retval |= register_edge_assert_for_1 (gimple_assign_rhs1 (op_def),
4375 else if (CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (op_def)))
4377 /* Recurse through the type conversion. */
4378 retval |= register_edge_assert_for_1 (gimple_assign_rhs1 (op_def),
4385 /* Try to register an edge assertion for SSA name NAME on edge E for
4386 the condition COND contributing to the conditional jump pointed to by SI.
4387 Return true if an assertion for NAME could be registered. */
4390 register_edge_assert_for (tree name, edge e, gimple_stmt_iterator si,
4391 enum tree_code cond_code, tree cond_op0,
4395 enum tree_code comp_code;
4396 bool retval = false;
4397 bool is_else_edge = (e->flags & EDGE_FALSE_VALUE) != 0;
4399 /* Do not attempt to infer anything in names that flow through
4401 if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (name))
4404 if (!extract_code_and_val_from_cond_with_ops (name, cond_code,
4410 /* Register ASSERT_EXPRs for name. */
4411 retval |= register_edge_assert_for_2 (name, e, si, cond_code, cond_op0,
4412 cond_op1, is_else_edge);
4415 /* If COND is effectively an equality test of an SSA_NAME against
4416 the value zero or one, then we may be able to assert values
4417 for SSA_NAMEs which flow into COND. */
4419 /* In the case of NAME == 1 or NAME != 0, for TRUTH_AND_EXPR defining
4420 statement of NAME we can assert both operands of the TRUTH_AND_EXPR
4421 have nonzero value. */
4422 if (((comp_code == EQ_EXPR && integer_onep (val))
4423 || (comp_code == NE_EXPR && integer_zerop (val))))
4425 gimple def_stmt = SSA_NAME_DEF_STMT (name);
4427 if (is_gimple_assign (def_stmt)
4428 && (gimple_assign_rhs_code (def_stmt) == TRUTH_AND_EXPR
4429 || gimple_assign_rhs_code (def_stmt) == BIT_AND_EXPR))
4431 tree op0 = gimple_assign_rhs1 (def_stmt);
4432 tree op1 = gimple_assign_rhs2 (def_stmt);
4433 retval |= register_edge_assert_for_1 (op0, NE_EXPR, e, si);
4434 retval |= register_edge_assert_for_1 (op1, NE_EXPR, e, si);
4438 /* In the case of NAME == 0 or NAME != 1, for TRUTH_OR_EXPR defining
4439 statement of NAME we can assert both operands of the TRUTH_OR_EXPR
4441 if (((comp_code == EQ_EXPR && integer_zerop (val))
4442 || (comp_code == NE_EXPR && integer_onep (val))))
4444 gimple def_stmt = SSA_NAME_DEF_STMT (name);
4446 if (is_gimple_assign (def_stmt)
4447 && (gimple_assign_rhs_code (def_stmt) == TRUTH_OR_EXPR
4448 /* For BIT_IOR_EXPR only if NAME == 0 both operands have
4449 necessarily zero value. */
4450 || (comp_code == EQ_EXPR
4451 && (gimple_assign_rhs_code (def_stmt) == BIT_IOR_EXPR))))
4453 tree op0 = gimple_assign_rhs1 (def_stmt);
4454 tree op1 = gimple_assign_rhs2 (def_stmt);
4455 retval |= register_edge_assert_for_1 (op0, EQ_EXPR, e, si);
4456 retval |= register_edge_assert_for_1 (op1, EQ_EXPR, e, si);
4464 /* Determine whether the outgoing edges of BB should receive an
4465 ASSERT_EXPR for each of the operands of BB's LAST statement.
4466 The last statement of BB must be a COND_EXPR.
4468 If any of the sub-graphs rooted at BB have an interesting use of
4469 the predicate operands, an assert location node is added to the
4470 list of assertions for the corresponding operands. */
4473 find_conditional_asserts (basic_block bb, gimple last)
4476 gimple_stmt_iterator bsi;
4482 need_assert = false;
4483 bsi = gsi_for_stmt (last);
4485 /* Look for uses of the operands in each of the sub-graphs
4486 rooted at BB. We need to check each of the outgoing edges
4487 separately, so that we know what kind of ASSERT_EXPR to
4489 FOR_EACH_EDGE (e, ei, bb->succs)
4494 /* Register the necessary assertions for each operand in the
4495 conditional predicate. */
4496 FOR_EACH_SSA_TREE_OPERAND (op, last, iter, SSA_OP_USE)
4498 need_assert |= register_edge_assert_for (op, e, bsi,
4499 gimple_cond_code (last),
4500 gimple_cond_lhs (last),
4501 gimple_cond_rhs (last));
4508 /* Compare two case labels sorting first by the destination label uid
4509 and then by the case value. */
4512 compare_case_labels (const void *p1, const void *p2)
4514 const_tree const case1 = *(const_tree const*)p1;
4515 const_tree const case2 = *(const_tree const*)p2;
4516 unsigned int uid1 = DECL_UID (CASE_LABEL (case1));
4517 unsigned int uid2 = DECL_UID (CASE_LABEL (case2));
4521 else if (uid1 == uid2)
4523 /* Make sure the default label is first in a group. */
4524 if (!CASE_LOW (case1))
4526 else if (!CASE_LOW (case2))
4529 return tree_int_cst_compare (CASE_LOW (case1), CASE_LOW (case2));
4535 /* Determine whether the outgoing edges of BB should receive an
4536 ASSERT_EXPR for each of the operands of BB's LAST statement.
4537 The last statement of BB must be a SWITCH_EXPR.
4539 If any of the sub-graphs rooted at BB have an interesting use of
4540 the predicate operands, an assert location node is added to the
4541 list of assertions for the corresponding operands. */
4544 find_switch_asserts (basic_block bb, gimple last)
4547 gimple_stmt_iterator bsi;
4551 size_t n = gimple_switch_num_labels(last);
4552 #if GCC_VERSION >= 4000
4555 /* Work around GCC 3.4 bug (PR 37086). */
4556 volatile unsigned int idx;
4559 need_assert = false;
4560 bsi = gsi_for_stmt (last);
4561 op = gimple_switch_index (last);
4562 if (TREE_CODE (op) != SSA_NAME)
4565 /* Build a vector of case labels sorted by destination label. */
4566 vec2 = make_tree_vec (n);
4567 for (idx = 0; idx < n; ++idx)
4568 TREE_VEC_ELT (vec2, idx) = gimple_switch_label (last, idx);
4569 qsort (&TREE_VEC_ELT (vec2, 0), n, sizeof (tree), compare_case_labels);
4571 for (idx = 0; idx < n; ++idx)
4574 tree cl = TREE_VEC_ELT (vec2, idx);
4576 min = CASE_LOW (cl);
4577 max = CASE_HIGH (cl);
4579 /* If there are multiple case labels with the same destination
4580 we need to combine them to a single value range for the edge. */
4582 && CASE_LABEL (cl) == CASE_LABEL (TREE_VEC_ELT (vec2, idx + 1)))
4584 /* Skip labels until the last of the group. */
4588 && CASE_LABEL (cl) == CASE_LABEL (TREE_VEC_ELT (vec2, idx)));
4591 /* Pick up the maximum of the case label range. */
4592 if (CASE_HIGH (TREE_VEC_ELT (vec2, idx)))
4593 max = CASE_HIGH (TREE_VEC_ELT (vec2, idx));
4595 max = CASE_LOW (TREE_VEC_ELT (vec2, idx));
4598 /* Nothing to do if the range includes the default label until we
4599 can register anti-ranges. */
4600 if (min == NULL_TREE)
4603 /* Find the edge to register the assert expr on. */
4604 e = find_edge (bb, label_to_block (CASE_LABEL (cl)));
4606 /* Register the necessary assertions for the operand in the
4608 need_assert |= register_edge_assert_for (op, e, bsi,
4609 max ? GE_EXPR : EQ_EXPR,
4611 fold_convert (TREE_TYPE (op),
4615 need_assert |= register_edge_assert_for (op, e, bsi, LE_EXPR,
4617 fold_convert (TREE_TYPE (op),
4626 /* Traverse all the statements in block BB looking for statements that
4627 may generate useful assertions for the SSA names in their operand.
4628 If a statement produces a useful assertion A for name N_i, then the
4629 list of assertions already generated for N_i is scanned to
4630 determine if A is actually needed.
4632 If N_i already had the assertion A at a location dominating the
4633 current location, then nothing needs to be done. Otherwise, the
4634 new location for A is recorded instead.
4636 1- For every statement S in BB, all the variables used by S are
4637 added to bitmap FOUND_IN_SUBGRAPH.
4639 2- If statement S uses an operand N in a way that exposes a known
4640 value range for N, then if N was not already generated by an
4641 ASSERT_EXPR, create a new assert location for N. For instance,
4642 if N is a pointer and the statement dereferences it, we can
4643 assume that N is not NULL.
4645 3- COND_EXPRs are a special case of #2. We can derive range
4646 information from the predicate but need to insert different
4647 ASSERT_EXPRs for each of the sub-graphs rooted at the
4648 conditional block. If the last statement of BB is a conditional
4649 expression of the form 'X op Y', then
4651 a) Remove X and Y from the set FOUND_IN_SUBGRAPH.
4653 b) If the conditional is the only entry point to the sub-graph
4654 corresponding to the THEN_CLAUSE, recurse into it. On
4655 return, if X and/or Y are marked in FOUND_IN_SUBGRAPH, then
4656 an ASSERT_EXPR is added for the corresponding variable.
4658 c) Repeat step (b) on the ELSE_CLAUSE.
4660 d) Mark X and Y in FOUND_IN_SUBGRAPH.
4669 In this case, an assertion on the THEN clause is useful to
4670 determine that 'a' is always 9 on that edge. However, an assertion
4671 on the ELSE clause would be unnecessary.
4673 4- If BB does not end in a conditional expression, then we recurse
4674 into BB's dominator children.
4676 At the end of the recursive traversal, every SSA name will have a
4677 list of locations where ASSERT_EXPRs should be added. When a new
4678 location for name N is found, it is registered by calling
4679 register_new_assert_for. That function keeps track of all the
4680 registered assertions to prevent adding unnecessary assertions.
4681 For instance, if a pointer P_4 is dereferenced more than once in a
4682 dominator tree, only the location dominating all the dereference of
4683 P_4 will receive an ASSERT_EXPR.
4685 If this function returns true, then it means that there are names
4686 for which we need to generate ASSERT_EXPRs. Those assertions are
4687 inserted by process_assert_insertions. */
4690 find_assert_locations_1 (basic_block bb, sbitmap live)
4692 gimple_stmt_iterator si;
4697 need_assert = false;
4698 last = last_stmt (bb);
4700 /* If BB's last statement is a conditional statement involving integer
4701 operands, determine if we need to add ASSERT_EXPRs. */
4703 && gimple_code (last) == GIMPLE_COND
4704 && !fp_predicate (last)
4705 && !ZERO_SSA_OPERANDS (last, SSA_OP_USE))
4706 need_assert |= find_conditional_asserts (bb, last);
4708 /* If BB's last statement is a switch statement involving integer
4709 operands, determine if we need to add ASSERT_EXPRs. */
4711 && gimple_code (last) == GIMPLE_SWITCH
4712 && !ZERO_SSA_OPERANDS (last, SSA_OP_USE))
4713 need_assert |= find_switch_asserts (bb, last);
4715 /* Traverse all the statements in BB marking used names and looking
4716 for statements that may infer assertions for their used operands. */
4717 for (si = gsi_start_bb (bb); !gsi_end_p (si); gsi_next (&si))
4723 stmt = gsi_stmt (si);
4725 if (is_gimple_debug (stmt))
4728 /* See if we can derive an assertion for any of STMT's operands. */
4729 FOR_EACH_SSA_TREE_OPERAND (op, stmt, i, SSA_OP_USE)
4732 enum tree_code comp_code;
4734 /* Mark OP in our live bitmap. */
4735 SET_BIT (live, SSA_NAME_VERSION (op));
4737 /* If OP is used in such a way that we can infer a value
4738 range for it, and we don't find a previous assertion for
4739 it, create a new assertion location node for OP. */
4740 if (infer_value_range (stmt, op, &comp_code, &value))
4742 /* If we are able to infer a nonzero value range for OP,
4743 then walk backwards through the use-def chain to see if OP
4744 was set via a typecast.
4746 If so, then we can also infer a nonzero value range
4747 for the operand of the NOP_EXPR. */
4748 if (comp_code == NE_EXPR && integer_zerop (value))
4751 gimple def_stmt = SSA_NAME_DEF_STMT (t);
4753 while (is_gimple_assign (def_stmt)
4754 && gimple_assign_rhs_code (def_stmt) == NOP_EXPR
4756 (gimple_assign_rhs1 (def_stmt)) == SSA_NAME
4758 (TREE_TYPE (gimple_assign_rhs1 (def_stmt))))
4760 t = gimple_assign_rhs1 (def_stmt);
4761 def_stmt = SSA_NAME_DEF_STMT (t);
4763 /* Note we want to register the assert for the
4764 operand of the NOP_EXPR after SI, not after the
4766 if (! has_single_use (t))
4768 register_new_assert_for (t, t, comp_code, value,
4775 /* If OP is used only once, namely in this STMT, don't
4776 bother creating an ASSERT_EXPR for it. Such an
4777 ASSERT_EXPR would do nothing but increase compile time. */
4778 if (!has_single_use (op))
4780 register_new_assert_for (op, op, comp_code, value,
4788 /* Traverse all PHI nodes in BB marking used operands. */
4789 for (si = gsi_start_phis (bb); !gsi_end_p(si); gsi_next (&si))
4791 use_operand_p arg_p;
4793 phi = gsi_stmt (si);
4795 FOR_EACH_PHI_ARG (arg_p, phi, i, SSA_OP_USE)
4797 tree arg = USE_FROM_PTR (arg_p);
4798 if (TREE_CODE (arg) == SSA_NAME)
4799 SET_BIT (live, SSA_NAME_VERSION (arg));
4806 /* Do an RPO walk over the function computing SSA name liveness
4807 on-the-fly and deciding on assert expressions to insert.
4808 Returns true if there are assert expressions to be inserted. */
4811 find_assert_locations (void)
4813 int *rpo = XCNEWVEC (int, last_basic_block + NUM_FIXED_BLOCKS);
4814 int *bb_rpo = XCNEWVEC (int, last_basic_block + NUM_FIXED_BLOCKS);
4815 int *last_rpo = XCNEWVEC (int, last_basic_block + NUM_FIXED_BLOCKS);
4819 live = XCNEWVEC (sbitmap, last_basic_block + NUM_FIXED_BLOCKS);
4820 rpo_cnt = pre_and_rev_post_order_compute (NULL, rpo, false);
4821 for (i = 0; i < rpo_cnt; ++i)
4824 need_asserts = false;
4825 for (i = rpo_cnt-1; i >= 0; --i)
4827 basic_block bb = BASIC_BLOCK (rpo[i]);
4833 live[rpo[i]] = sbitmap_alloc (num_ssa_names);
4834 sbitmap_zero (live[rpo[i]]);
4837 /* Process BB and update the live information with uses in
4839 need_asserts |= find_assert_locations_1 (bb, live[rpo[i]]);
4841 /* Merge liveness into the predecessor blocks and free it. */
4842 if (!sbitmap_empty_p (live[rpo[i]]))
4845 FOR_EACH_EDGE (e, ei, bb->preds)
4847 int pred = e->src->index;
4848 if (e->flags & EDGE_DFS_BACK)
4853 live[pred] = sbitmap_alloc (num_ssa_names);
4854 sbitmap_zero (live[pred]);
4856 sbitmap_a_or_b (live[pred], live[pred], live[rpo[i]]);
4858 if (bb_rpo[pred] < pred_rpo)
4859 pred_rpo = bb_rpo[pred];
4862 /* Record the RPO number of the last visited block that needs
4863 live information from this block. */
4864 last_rpo[rpo[i]] = pred_rpo;
4868 sbitmap_free (live[rpo[i]]);
4869 live[rpo[i]] = NULL;
4872 /* We can free all successors live bitmaps if all their
4873 predecessors have been visited already. */
4874 FOR_EACH_EDGE (e, ei, bb->succs)
4875 if (last_rpo[e->dest->index] == i
4876 && live[e->dest->index])
4878 sbitmap_free (live[e->dest->index]);
4879 live[e->dest->index] = NULL;
4884 XDELETEVEC (bb_rpo);
4885 XDELETEVEC (last_rpo);
4886 for (i = 0; i < last_basic_block + NUM_FIXED_BLOCKS; ++i)
4888 sbitmap_free (live[i]);
4891 return need_asserts;
4894 /* Create an ASSERT_EXPR for NAME and insert it in the location
4895 indicated by LOC. Return true if we made any edge insertions. */
4898 process_assert_insertions_for (tree name, assert_locus_t loc)
4900 /* Build the comparison expression NAME_i COMP_CODE VAL. */
4907 /* If we have X <=> X do not insert an assert expr for that. */
4908 if (loc->expr == loc->val)
4911 cond = build2 (loc->comp_code, boolean_type_node, loc->expr, loc->val);
4912 assert_stmt = build_assert_expr_for (cond, name);
4915 /* We have been asked to insert the assertion on an edge. This
4916 is used only by COND_EXPR and SWITCH_EXPR assertions. */
4917 #if defined ENABLE_CHECKING
4918 gcc_assert (gimple_code (gsi_stmt (loc->si)) == GIMPLE_COND
4919 || gimple_code (gsi_stmt (loc->si)) == GIMPLE_SWITCH);
4922 gsi_insert_on_edge (loc->e, assert_stmt);
4926 /* Otherwise, we can insert right after LOC->SI iff the
4927 statement must not be the last statement in the block. */
4928 stmt = gsi_stmt (loc->si);
4929 if (!stmt_ends_bb_p (stmt))
4931 gsi_insert_after (&loc->si, assert_stmt, GSI_SAME_STMT);
4935 /* If STMT must be the last statement in BB, we can only insert new
4936 assertions on the non-abnormal edge out of BB. Note that since
4937 STMT is not control flow, there may only be one non-abnormal edge
4939 FOR_EACH_EDGE (e, ei, loc->bb->succs)
4940 if (!(e->flags & EDGE_ABNORMAL))
4942 gsi_insert_on_edge (e, assert_stmt);
4950 /* Process all the insertions registered for every name N_i registered
4951 in NEED_ASSERT_FOR. The list of assertions to be inserted are
4952 found in ASSERTS_FOR[i]. */
4955 process_assert_insertions (void)
4959 bool update_edges_p = false;
4960 int num_asserts = 0;
4962 if (dump_file && (dump_flags & TDF_DETAILS))
4963 dump_all_asserts (dump_file);
4965 EXECUTE_IF_SET_IN_BITMAP (need_assert_for, 0, i, bi)
4967 assert_locus_t loc = asserts_for[i];
4972 assert_locus_t next = loc->next;
4973 update_edges_p |= process_assert_insertions_for (ssa_name (i), loc);
4981 gsi_commit_edge_inserts ();
4983 statistics_counter_event (cfun, "Number of ASSERT_EXPR expressions inserted",
4988 /* Traverse the flowgraph looking for conditional jumps to insert range
4989 expressions. These range expressions are meant to provide information
4990 to optimizations that need to reason in terms of value ranges. They
4991 will not be expanded into RTL. For instance, given:
5000 this pass will transform the code into:
5006 x = ASSERT_EXPR <x, x < y>
5011 y = ASSERT_EXPR <y, x <= y>
5015 The idea is that once copy and constant propagation have run, other
5016 optimizations will be able to determine what ranges of values can 'x'
5017 take in different paths of the code, simply by checking the reaching
5018 definition of 'x'. */
5021 insert_range_assertions (void)
5023 need_assert_for = BITMAP_ALLOC (NULL);
5024 asserts_for = XCNEWVEC (assert_locus_t, num_ssa_names);
5026 calculate_dominance_info (CDI_DOMINATORS);
5028 if (find_assert_locations ())
5030 process_assert_insertions ();
5031 update_ssa (TODO_update_ssa_no_phi);
5034 if (dump_file && (dump_flags & TDF_DETAILS))
5036 fprintf (dump_file, "\nSSA form after inserting ASSERT_EXPRs\n");
5037 dump_function_to_file (current_function_decl, dump_file, dump_flags);
5041 BITMAP_FREE (need_assert_for);
5044 /* Checks one ARRAY_REF in REF, located at LOCUS. Ignores flexible arrays
5045 and "struct" hacks. If VRP can determine that the
5046 array subscript is a constant, check if it is outside valid
5047 range. If the array subscript is a RANGE, warn if it is
5048 non-overlapping with valid range.
5049 IGNORE_OFF_BY_ONE is true if the ARRAY_REF is inside a ADDR_EXPR. */
5052 check_array_ref (location_t location, tree ref, bool ignore_off_by_one)
5054 value_range_t* vr = NULL;
5055 tree low_sub, up_sub;
5056 tree low_bound, up_bound, up_bound_p1;
5059 if (TREE_NO_WARNING (ref))
5062 low_sub = up_sub = TREE_OPERAND (ref, 1);
5063 up_bound = array_ref_up_bound (ref);
5065 /* Can not check flexible arrays. */
5067 || TREE_CODE (up_bound) != INTEGER_CST)
5070 /* Accesses to trailing arrays via pointers may access storage
5071 beyond the types array bounds. */
5072 base = get_base_address (ref);
5074 && INDIRECT_REF_P (base))
5076 tree cref, next = NULL_TREE;
5078 if (TREE_CODE (TREE_OPERAND (ref, 0)) != COMPONENT_REF)
5081 cref = TREE_OPERAND (ref, 0);
5082 if (TREE_CODE (TREE_TYPE (TREE_OPERAND (cref, 0))) == RECORD_TYPE)
5083 for (next = TREE_CHAIN (TREE_OPERAND (cref, 1));
5084 next && TREE_CODE (next) != FIELD_DECL;
5085 next = TREE_CHAIN (next))
5088 /* If this is the last field in a struct type or a field in a
5089 union type do not warn. */
5094 low_bound = array_ref_low_bound (ref);
5095 up_bound_p1 = int_const_binop (PLUS_EXPR, up_bound, integer_one_node, 0);
5097 if (TREE_CODE (low_sub) == SSA_NAME)
5099 vr = get_value_range (low_sub);
5100 if (vr->type == VR_RANGE || vr->type == VR_ANTI_RANGE)
5102 low_sub = vr->type == VR_RANGE ? vr->max : vr->min;
5103 up_sub = vr->type == VR_RANGE ? vr->min : vr->max;
5107 if (vr && vr->type == VR_ANTI_RANGE)
5109 if (TREE_CODE (up_sub) == INTEGER_CST
5110 && tree_int_cst_lt (up_bound, up_sub)
5111 && TREE_CODE (low_sub) == INTEGER_CST
5112 && tree_int_cst_lt (low_sub, low_bound))
5114 warning_at (location, OPT_Warray_bounds,
5115 "array subscript is outside array bounds");
5116 TREE_NO_WARNING (ref) = 1;
5119 else if (TREE_CODE (up_sub) == INTEGER_CST
5120 && (ignore_off_by_one
5121 ? (tree_int_cst_lt (up_bound, up_sub)
5122 && !tree_int_cst_equal (up_bound_p1, up_sub))
5123 : (tree_int_cst_lt (up_bound, up_sub)
5124 || tree_int_cst_equal (up_bound_p1, up_sub))))
5126 warning_at (location, OPT_Warray_bounds,
5127 "array subscript is above array bounds");
5128 TREE_NO_WARNING (ref) = 1;
5130 else if (TREE_CODE (low_sub) == INTEGER_CST
5131 && tree_int_cst_lt (low_sub, low_bound))
5133 warning_at (location, OPT_Warray_bounds,
5134 "array subscript is below array bounds");
5135 TREE_NO_WARNING (ref) = 1;
5139 /* Searches if the expr T, located at LOCATION computes
5140 address of an ARRAY_REF, and call check_array_ref on it. */
5143 search_for_addr_array (tree t, location_t location)
5145 while (TREE_CODE (t) == SSA_NAME)
5147 gimple g = SSA_NAME_DEF_STMT (t);
5149 if (gimple_code (g) != GIMPLE_ASSIGN)
5152 if (get_gimple_rhs_class (gimple_assign_rhs_code (g))
5153 != GIMPLE_SINGLE_RHS)
5156 t = gimple_assign_rhs1 (g);
5160 /* We are only interested in addresses of ARRAY_REF's. */
5161 if (TREE_CODE (t) != ADDR_EXPR)
5164 /* Check each ARRAY_REFs in the reference chain. */
5167 if (TREE_CODE (t) == ARRAY_REF)
5168 check_array_ref (location, t, true /*ignore_off_by_one*/);
5170 t = TREE_OPERAND (t, 0);
5172 while (handled_component_p (t));
5175 /* walk_tree() callback that checks if *TP is
5176 an ARRAY_REF inside an ADDR_EXPR (in which an array
5177 subscript one outside the valid range is allowed). Call
5178 check_array_ref for each ARRAY_REF found. The location is
5182 check_array_bounds (tree *tp, int *walk_subtree, void *data)
5185 struct walk_stmt_info *wi = (struct walk_stmt_info *) data;
5186 location_t location;
5188 if (EXPR_HAS_LOCATION (t))
5189 location = EXPR_LOCATION (t);
5192 location_t *locp = (location_t *) wi->info;
5196 *walk_subtree = TRUE;
5198 if (TREE_CODE (t) == ARRAY_REF)
5199 check_array_ref (location, t, false /*ignore_off_by_one*/);
5201 if (TREE_CODE (t) == INDIRECT_REF
5202 || (TREE_CODE (t) == RETURN_EXPR && TREE_OPERAND (t, 0)))
5203 search_for_addr_array (TREE_OPERAND (t, 0), location);
5205 if (TREE_CODE (t) == ADDR_EXPR)
5206 *walk_subtree = FALSE;
5211 /* Walk over all statements of all reachable BBs and call check_array_bounds
5215 check_all_array_refs (void)
5218 gimple_stmt_iterator si;
5224 bool executable = false;
5226 /* Skip blocks that were found to be unreachable. */
5227 FOR_EACH_EDGE (e, ei, bb->preds)
5228 executable |= !!(e->flags & EDGE_EXECUTABLE);
5232 for (si = gsi_start_bb (bb); !gsi_end_p (si); gsi_next (&si))
5234 gimple stmt = gsi_stmt (si);
5235 struct walk_stmt_info wi;
5236 if (!gimple_has_location (stmt))
5239 if (is_gimple_call (stmt))
5242 size_t n = gimple_call_num_args (stmt);
5243 for (i = 0; i < n; i++)
5245 tree arg = gimple_call_arg (stmt, i);
5246 search_for_addr_array (arg, gimple_location (stmt));
5251 memset (&wi, 0, sizeof (wi));
5252 wi.info = CONST_CAST (void *, (const void *)
5253 gimple_location_ptr (stmt));
5255 walk_gimple_op (gsi_stmt (si),
5263 /* Convert range assertion expressions into the implied copies and
5264 copy propagate away the copies. Doing the trivial copy propagation
5265 here avoids the need to run the full copy propagation pass after
5268 FIXME, this will eventually lead to copy propagation removing the
5269 names that had useful range information attached to them. For
5270 instance, if we had the assertion N_i = ASSERT_EXPR <N_j, N_j > 3>,
5271 then N_i will have the range [3, +INF].
5273 However, by converting the assertion into the implied copy
5274 operation N_i = N_j, we will then copy-propagate N_j into the uses
5275 of N_i and lose the range information. We may want to hold on to
5276 ASSERT_EXPRs a little while longer as the ranges could be used in
5277 things like jump threading.
5279 The problem with keeping ASSERT_EXPRs around is that passes after
5280 VRP need to handle them appropriately.
5282 Another approach would be to make the range information a first
5283 class property of the SSA_NAME so that it can be queried from
5284 any pass. This is made somewhat more complex by the need for
5285 multiple ranges to be associated with one SSA_NAME. */
5288 remove_range_assertions (void)
5291 gimple_stmt_iterator si;
5293 /* Note that the BSI iterator bump happens at the bottom of the
5294 loop and no bump is necessary if we're removing the statement
5295 referenced by the current BSI. */
5297 for (si = gsi_start_bb (bb); !gsi_end_p (si);)
5299 gimple stmt = gsi_stmt (si);
5302 if (is_gimple_assign (stmt)
5303 && gimple_assign_rhs_code (stmt) == ASSERT_EXPR)
5305 tree rhs = gimple_assign_rhs1 (stmt);
5307 tree cond = fold (ASSERT_EXPR_COND (rhs));
5308 use_operand_p use_p;
5309 imm_use_iterator iter;
5311 gcc_assert (cond != boolean_false_node);
5313 /* Propagate the RHS into every use of the LHS. */
5314 var = ASSERT_EXPR_VAR (rhs);
5315 FOR_EACH_IMM_USE_STMT (use_stmt, iter,
5316 gimple_assign_lhs (stmt))
5317 FOR_EACH_IMM_USE_ON_STMT (use_p, iter)
5319 SET_USE (use_p, var);
5320 gcc_assert (TREE_CODE (var) == SSA_NAME);
5323 /* And finally, remove the copy, it is not needed. */
5324 gsi_remove (&si, true);
5325 release_defs (stmt);
5333 /* Return true if STMT is interesting for VRP. */
5336 stmt_interesting_for_vrp (gimple stmt)
5338 if (gimple_code (stmt) == GIMPLE_PHI
5339 && is_gimple_reg (gimple_phi_result (stmt))
5340 && (INTEGRAL_TYPE_P (TREE_TYPE (gimple_phi_result (stmt)))
5341 || POINTER_TYPE_P (TREE_TYPE (gimple_phi_result (stmt)))))
5343 else if (is_gimple_assign (stmt) || is_gimple_call (stmt))
5345 tree lhs = gimple_get_lhs (stmt);
5347 /* In general, assignments with virtual operands are not useful
5348 for deriving ranges, with the obvious exception of calls to
5349 builtin functions. */
5350 if (lhs && TREE_CODE (lhs) == SSA_NAME
5351 && (INTEGRAL_TYPE_P (TREE_TYPE (lhs))
5352 || POINTER_TYPE_P (TREE_TYPE (lhs)))
5353 && ((is_gimple_call (stmt)
5354 && gimple_call_fndecl (stmt) != NULL_TREE
5355 && DECL_IS_BUILTIN (gimple_call_fndecl (stmt)))
5356 || !gimple_vuse (stmt)))
5359 else if (gimple_code (stmt) == GIMPLE_COND
5360 || gimple_code (stmt) == GIMPLE_SWITCH)
5367 /* Initialize local data structures for VRP. */
5370 vrp_initialize (void)
5374 vr_value = XCNEWVEC (value_range_t *, num_ssa_names);
5375 vr_phi_edge_counts = XCNEWVEC (int, num_ssa_names);
5379 gimple_stmt_iterator si;
5381 for (si = gsi_start_phis (bb); !gsi_end_p (si); gsi_next (&si))
5383 gimple phi = gsi_stmt (si);
5384 if (!stmt_interesting_for_vrp (phi))
5386 tree lhs = PHI_RESULT (phi);
5387 set_value_range_to_varying (get_value_range (lhs));
5388 prop_set_simulate_again (phi, false);
5391 prop_set_simulate_again (phi, true);
5394 for (si = gsi_start_bb (bb); !gsi_end_p (si); gsi_next (&si))
5396 gimple stmt = gsi_stmt (si);
5398 /* If the statement is a control insn, then we do not
5399 want to avoid simulating the statement once. Failure
5400 to do so means that those edges will never get added. */
5401 if (stmt_ends_bb_p (stmt))
5402 prop_set_simulate_again (stmt, true);
5403 else if (!stmt_interesting_for_vrp (stmt))
5407 FOR_EACH_SSA_TREE_OPERAND (def, stmt, i, SSA_OP_DEF)
5408 set_value_range_to_varying (get_value_range (def));
5409 prop_set_simulate_again (stmt, false);
5412 prop_set_simulate_again (stmt, true);
5418 /* Visit assignment STMT. If it produces an interesting range, record
5419 the SSA name in *OUTPUT_P. */
5421 static enum ssa_prop_result
5422 vrp_visit_assignment_or_call (gimple stmt, tree *output_p)
5426 enum gimple_code code = gimple_code (stmt);
5427 lhs = gimple_get_lhs (stmt);
5429 /* We only keep track of ranges in integral and pointer types. */
5430 if (TREE_CODE (lhs) == SSA_NAME
5431 && ((INTEGRAL_TYPE_P (TREE_TYPE (lhs))
5432 /* It is valid to have NULL MIN/MAX values on a type. See
5433 build_range_type. */
5434 && TYPE_MIN_VALUE (TREE_TYPE (lhs))
5435 && TYPE_MAX_VALUE (TREE_TYPE (lhs)))
5436 || POINTER_TYPE_P (TREE_TYPE (lhs))))
5438 value_range_t new_vr = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
5440 if (code == GIMPLE_CALL)
5441 extract_range_basic (&new_vr, stmt);
5443 extract_range_from_assignment (&new_vr, stmt);
5445 if (update_value_range (lhs, &new_vr))
5449 if (dump_file && (dump_flags & TDF_DETAILS))
5451 fprintf (dump_file, "Found new range for ");
5452 print_generic_expr (dump_file, lhs, 0);
5453 fprintf (dump_file, ": ");
5454 dump_value_range (dump_file, &new_vr);
5455 fprintf (dump_file, "\n\n");
5458 if (new_vr.type == VR_VARYING)
5459 return SSA_PROP_VARYING;
5461 return SSA_PROP_INTERESTING;
5464 return SSA_PROP_NOT_INTERESTING;
5467 /* Every other statement produces no useful ranges. */
5468 FOR_EACH_SSA_TREE_OPERAND (def, stmt, iter, SSA_OP_DEF)
5469 set_value_range_to_varying (get_value_range (def));
5471 return SSA_PROP_VARYING;
5474 /* Helper that gets the value range of the SSA_NAME with version I
5475 or a symbolic range containing the SSA_NAME only if the value range
5476 is varying or undefined. */
5478 static inline value_range_t
5479 get_vr_for_comparison (int i)
5481 value_range_t vr = *(vr_value[i]);
5483 /* If name N_i does not have a valid range, use N_i as its own
5484 range. This allows us to compare against names that may
5485 have N_i in their ranges. */
5486 if (vr.type == VR_VARYING || vr.type == VR_UNDEFINED)
5489 vr.min = ssa_name (i);
5490 vr.max = ssa_name (i);
5496 /* Compare all the value ranges for names equivalent to VAR with VAL
5497 using comparison code COMP. Return the same value returned by
5498 compare_range_with_value, including the setting of
5499 *STRICT_OVERFLOW_P. */
5502 compare_name_with_value (enum tree_code comp, tree var, tree val,
5503 bool *strict_overflow_p)
5509 int used_strict_overflow;
5511 value_range_t equiv_vr;
5513 /* Get the set of equivalences for VAR. */
5514 e = get_value_range (var)->equiv;
5516 /* Start at -1. Set it to 0 if we do a comparison without relying
5517 on overflow, or 1 if all comparisons rely on overflow. */
5518 used_strict_overflow = -1;
5520 /* Compare vars' value range with val. */
5521 equiv_vr = get_vr_for_comparison (SSA_NAME_VERSION (var));
5523 retval = compare_range_with_value (comp, &equiv_vr, val, &sop);
5525 used_strict_overflow = sop ? 1 : 0;
5527 /* If the equiv set is empty we have done all work we need to do. */
5531 && used_strict_overflow > 0)
5532 *strict_overflow_p = true;
5536 EXECUTE_IF_SET_IN_BITMAP (e, 0, i, bi)
5538 equiv_vr = get_vr_for_comparison (i);
5540 t = compare_range_with_value (comp, &equiv_vr, val, &sop);
5543 /* If we get different answers from different members
5544 of the equivalence set this check must be in a dead
5545 code region. Folding it to a trap representation
5546 would be correct here. For now just return don't-know. */
5556 used_strict_overflow = 0;
5557 else if (used_strict_overflow < 0)
5558 used_strict_overflow = 1;
5563 && used_strict_overflow > 0)
5564 *strict_overflow_p = true;
5570 /* Given a comparison code COMP and names N1 and N2, compare all the
5571 ranges equivalent to N1 against all the ranges equivalent to N2
5572 to determine the value of N1 COMP N2. Return the same value
5573 returned by compare_ranges. Set *STRICT_OVERFLOW_P to indicate
5574 whether we relied on an overflow infinity in the comparison. */
5578 compare_names (enum tree_code comp, tree n1, tree n2,
5579 bool *strict_overflow_p)
5583 bitmap_iterator bi1, bi2;
5585 int used_strict_overflow;
5586 static bitmap_obstack *s_obstack = NULL;
5587 static bitmap s_e1 = NULL, s_e2 = NULL;
5589 /* Compare the ranges of every name equivalent to N1 against the
5590 ranges of every name equivalent to N2. */
5591 e1 = get_value_range (n1)->equiv;
5592 e2 = get_value_range (n2)->equiv;
5594 /* Use the fake bitmaps if e1 or e2 are not available. */
5595 if (s_obstack == NULL)
5597 s_obstack = XNEW (bitmap_obstack);
5598 bitmap_obstack_initialize (s_obstack);
5599 s_e1 = BITMAP_ALLOC (s_obstack);
5600 s_e2 = BITMAP_ALLOC (s_obstack);
5607 /* Add N1 and N2 to their own set of equivalences to avoid
5608 duplicating the body of the loop just to check N1 and N2
5610 bitmap_set_bit (e1, SSA_NAME_VERSION (n1));
5611 bitmap_set_bit (e2, SSA_NAME_VERSION (n2));
5613 /* If the equivalence sets have a common intersection, then the two
5614 names can be compared without checking their ranges. */
5615 if (bitmap_intersect_p (e1, e2))
5617 bitmap_clear_bit (e1, SSA_NAME_VERSION (n1));
5618 bitmap_clear_bit (e2, SSA_NAME_VERSION (n2));
5620 return (comp == EQ_EXPR || comp == GE_EXPR || comp == LE_EXPR)
5622 : boolean_false_node;
5625 /* Start at -1. Set it to 0 if we do a comparison without relying
5626 on overflow, or 1 if all comparisons rely on overflow. */
5627 used_strict_overflow = -1;
5629 /* Otherwise, compare all the equivalent ranges. First, add N1 and
5630 N2 to their own set of equivalences to avoid duplicating the body
5631 of the loop just to check N1 and N2 ranges. */
5632 EXECUTE_IF_SET_IN_BITMAP (e1, 0, i1, bi1)
5634 value_range_t vr1 = get_vr_for_comparison (i1);
5636 t = retval = NULL_TREE;
5637 EXECUTE_IF_SET_IN_BITMAP (e2, 0, i2, bi2)
5641 value_range_t vr2 = get_vr_for_comparison (i2);
5643 t = compare_ranges (comp, &vr1, &vr2, &sop);
5646 /* If we get different answers from different members
5647 of the equivalence set this check must be in a dead
5648 code region. Folding it to a trap representation
5649 would be correct here. For now just return don't-know. */
5653 bitmap_clear_bit (e1, SSA_NAME_VERSION (n1));
5654 bitmap_clear_bit (e2, SSA_NAME_VERSION (n2));
5660 used_strict_overflow = 0;
5661 else if (used_strict_overflow < 0)
5662 used_strict_overflow = 1;
5668 bitmap_clear_bit (e1, SSA_NAME_VERSION (n1));
5669 bitmap_clear_bit (e2, SSA_NAME_VERSION (n2));
5670 if (used_strict_overflow > 0)
5671 *strict_overflow_p = true;
5676 /* None of the equivalent ranges are useful in computing this
5678 bitmap_clear_bit (e1, SSA_NAME_VERSION (n1));
5679 bitmap_clear_bit (e2, SSA_NAME_VERSION (n2));
5683 /* Helper function for vrp_evaluate_conditional_warnv. */
5686 vrp_evaluate_conditional_warnv_with_ops_using_ranges (enum tree_code code,
5688 bool * strict_overflow_p)
5690 value_range_t *vr0, *vr1;
5692 vr0 = (TREE_CODE (op0) == SSA_NAME) ? get_value_range (op0) : NULL;
5693 vr1 = (TREE_CODE (op1) == SSA_NAME) ? get_value_range (op1) : NULL;
5696 return compare_ranges (code, vr0, vr1, strict_overflow_p);
5697 else if (vr0 && vr1 == NULL)
5698 return compare_range_with_value (code, vr0, op1, strict_overflow_p);
5699 else if (vr0 == NULL && vr1)
5700 return (compare_range_with_value
5701 (swap_tree_comparison (code), vr1, op0, strict_overflow_p));
5705 /* Helper function for vrp_evaluate_conditional_warnv. */
5708 vrp_evaluate_conditional_warnv_with_ops (enum tree_code code, tree op0,
5709 tree op1, bool use_equiv_p,
5710 bool *strict_overflow_p, bool *only_ranges)
5714 *only_ranges = true;
5716 /* We only deal with integral and pointer types. */
5717 if (!INTEGRAL_TYPE_P (TREE_TYPE (op0))
5718 && !POINTER_TYPE_P (TREE_TYPE (op0)))
5724 && (ret = vrp_evaluate_conditional_warnv_with_ops_using_ranges
5725 (code, op0, op1, strict_overflow_p)))
5727 *only_ranges = false;
5728 if (TREE_CODE (op0) == SSA_NAME && TREE_CODE (op1) == SSA_NAME)
5729 return compare_names (code, op0, op1, strict_overflow_p);
5730 else if (TREE_CODE (op0) == SSA_NAME)
5731 return compare_name_with_value (code, op0, op1, strict_overflow_p);
5732 else if (TREE_CODE (op1) == SSA_NAME)
5733 return (compare_name_with_value
5734 (swap_tree_comparison (code), op1, op0, strict_overflow_p));
5737 return vrp_evaluate_conditional_warnv_with_ops_using_ranges (code, op0, op1,
5742 /* Given (CODE OP0 OP1) within STMT, try to simplify it based on value range
5743 information. Return NULL if the conditional can not be evaluated.
5744 The ranges of all the names equivalent with the operands in COND
5745 will be used when trying to compute the value. If the result is
5746 based on undefined signed overflow, issue a warning if
5750 vrp_evaluate_conditional (enum tree_code code, tree op0, tree op1, gimple stmt)
5756 /* Some passes and foldings leak constants with overflow flag set
5757 into the IL. Avoid doing wrong things with these and bail out. */
5758 if ((TREE_CODE (op0) == INTEGER_CST
5759 && TREE_OVERFLOW (op0))
5760 || (TREE_CODE (op1) == INTEGER_CST
5761 && TREE_OVERFLOW (op1)))
5765 ret = vrp_evaluate_conditional_warnv_with_ops (code, op0, op1, true, &sop,
5770 enum warn_strict_overflow_code wc;
5771 const char* warnmsg;
5773 if (is_gimple_min_invariant (ret))
5775 wc = WARN_STRICT_OVERFLOW_CONDITIONAL;
5776 warnmsg = G_("assuming signed overflow does not occur when "
5777 "simplifying conditional to constant");
5781 wc = WARN_STRICT_OVERFLOW_COMPARISON;
5782 warnmsg = G_("assuming signed overflow does not occur when "
5783 "simplifying conditional");
5786 if (issue_strict_overflow_warning (wc))
5788 location_t location;
5790 if (!gimple_has_location (stmt))
5791 location = input_location;
5793 location = gimple_location (stmt);
5794 warning_at (location, OPT_Wstrict_overflow, "%s", warnmsg);
5798 if (warn_type_limits
5799 && ret && only_ranges
5800 && TREE_CODE_CLASS (code) == tcc_comparison
5801 && TREE_CODE (op0) == SSA_NAME)
5803 /* If the comparison is being folded and the operand on the LHS
5804 is being compared against a constant value that is outside of
5805 the natural range of OP0's type, then the predicate will
5806 always fold regardless of the value of OP0. If -Wtype-limits
5807 was specified, emit a warning. */
5808 tree type = TREE_TYPE (op0);
5809 value_range_t *vr0 = get_value_range (op0);
5811 if (vr0->type != VR_VARYING
5812 && INTEGRAL_TYPE_P (type)
5813 && vrp_val_is_min (vr0->min)
5814 && vrp_val_is_max (vr0->max)
5815 && is_gimple_min_invariant (op1))
5817 location_t location;
5819 if (!gimple_has_location (stmt))
5820 location = input_location;
5822 location = gimple_location (stmt);
5824 warning_at (location, OPT_Wtype_limits,
5826 ? G_("comparison always false "
5827 "due to limited range of data type")
5828 : G_("comparison always true "
5829 "due to limited range of data type"));
5837 /* Visit conditional statement STMT. If we can determine which edge
5838 will be taken out of STMT's basic block, record it in
5839 *TAKEN_EDGE_P and return SSA_PROP_INTERESTING. Otherwise, return
5840 SSA_PROP_VARYING. */
5842 static enum ssa_prop_result
5843 vrp_visit_cond_stmt (gimple stmt, edge *taken_edge_p)
5848 *taken_edge_p = NULL;
5850 if (dump_file && (dump_flags & TDF_DETAILS))
5855 fprintf (dump_file, "\nVisiting conditional with predicate: ");
5856 print_gimple_stmt (dump_file, stmt, 0, 0);
5857 fprintf (dump_file, "\nWith known ranges\n");
5859 FOR_EACH_SSA_TREE_OPERAND (use, stmt, i, SSA_OP_USE)
5861 fprintf (dump_file, "\t");
5862 print_generic_expr (dump_file, use, 0);
5863 fprintf (dump_file, ": ");
5864 dump_value_range (dump_file, vr_value[SSA_NAME_VERSION (use)]);
5867 fprintf (dump_file, "\n");
5870 /* Compute the value of the predicate COND by checking the known
5871 ranges of each of its operands.
5873 Note that we cannot evaluate all the equivalent ranges here
5874 because those ranges may not yet be final and with the current
5875 propagation strategy, we cannot determine when the value ranges
5876 of the names in the equivalence set have changed.
5878 For instance, given the following code fragment
5882 i_14 = ASSERT_EXPR <i_5, i_5 != 0>
5886 Assume that on the first visit to i_14, i_5 has the temporary
5887 range [8, 8] because the second argument to the PHI function is
5888 not yet executable. We derive the range ~[0, 0] for i_14 and the
5889 equivalence set { i_5 }. So, when we visit 'if (i_14 == 1)' for
5890 the first time, since i_14 is equivalent to the range [8, 8], we
5891 determine that the predicate is always false.
5893 On the next round of propagation, i_13 is determined to be
5894 VARYING, which causes i_5 to drop down to VARYING. So, another
5895 visit to i_14 is scheduled. In this second visit, we compute the
5896 exact same range and equivalence set for i_14, namely ~[0, 0] and
5897 { i_5 }. But we did not have the previous range for i_5
5898 registered, so vrp_visit_assignment thinks that the range for
5899 i_14 has not changed. Therefore, the predicate 'if (i_14 == 1)'
5900 is not visited again, which stops propagation from visiting
5901 statements in the THEN clause of that if().
5903 To properly fix this we would need to keep the previous range
5904 value for the names in the equivalence set. This way we would've
5905 discovered that from one visit to the other i_5 changed from
5906 range [8, 8] to VR_VARYING.
5908 However, fixing this apparent limitation may not be worth the
5909 additional checking. Testing on several code bases (GCC, DLV,
5910 MICO, TRAMP3D and SPEC2000) showed that doing this results in
5911 4 more predicates folded in SPEC. */
5914 val = vrp_evaluate_conditional_warnv_with_ops (gimple_cond_code (stmt),
5915 gimple_cond_lhs (stmt),
5916 gimple_cond_rhs (stmt),
5921 *taken_edge_p = find_taken_edge (gimple_bb (stmt), val);
5924 if (dump_file && (dump_flags & TDF_DETAILS))
5926 "\nIgnoring predicate evaluation because "
5927 "it assumes that signed overflow is undefined");
5932 if (dump_file && (dump_flags & TDF_DETAILS))
5934 fprintf (dump_file, "\nPredicate evaluates to: ");
5935 if (val == NULL_TREE)
5936 fprintf (dump_file, "DON'T KNOW\n");
5938 print_generic_stmt (dump_file, val, 0);
5941 return (*taken_edge_p) ? SSA_PROP_INTERESTING : SSA_PROP_VARYING;
5944 /* Searches the case label vector VEC for the index *IDX of the CASE_LABEL
5945 that includes the value VAL. The search is restricted to the range
5946 [START_IDX, n - 1] where n is the size of VEC.
5948 If there is a CASE_LABEL for VAL, its index is placed in IDX and true is
5951 If there is no CASE_LABEL for VAL and there is one that is larger than VAL,
5952 it is placed in IDX and false is returned.
5954 If VAL is larger than any CASE_LABEL, n is placed on IDX and false is
5958 find_case_label_index (gimple stmt, size_t start_idx, tree val, size_t *idx)
5960 size_t n = gimple_switch_num_labels (stmt);
5963 /* Find case label for minimum of the value range or the next one.
5964 At each iteration we are searching in [low, high - 1]. */
5966 for (low = start_idx, high = n; high != low; )
5970 /* Note that i != high, so we never ask for n. */
5971 size_t i = (high + low) / 2;
5972 t = gimple_switch_label (stmt, i);
5974 /* Cache the result of comparing CASE_LOW and val. */
5975 cmp = tree_int_cst_compare (CASE_LOW (t), val);
5979 /* Ranges cannot be empty. */
5988 if (CASE_HIGH (t) != NULL
5989 && tree_int_cst_compare (CASE_HIGH (t), val) >= 0)
6001 /* Searches the case label vector VEC for the range of CASE_LABELs that is used
6002 for values between MIN and MAX. The first index is placed in MIN_IDX. The
6003 last index is placed in MAX_IDX. If the range of CASE_LABELs is empty
6004 then MAX_IDX < MIN_IDX.
6005 Returns true if the default label is not needed. */
6008 find_case_label_range (gimple stmt, tree min, tree max, size_t *min_idx,
6012 bool min_take_default = !find_case_label_index (stmt, 1, min, &i);
6013 bool max_take_default = !find_case_label_index (stmt, i, max, &j);
6017 && max_take_default)
6019 /* Only the default case label reached.
6020 Return an empty range. */
6027 bool take_default = min_take_default || max_take_default;
6031 if (max_take_default)
6034 /* If the case label range is continuous, we do not need
6035 the default case label. Verify that. */
6036 high = CASE_LOW (gimple_switch_label (stmt, i));
6037 if (CASE_HIGH (gimple_switch_label (stmt, i)))
6038 high = CASE_HIGH (gimple_switch_label (stmt, i));
6039 for (k = i + 1; k <= j; ++k)
6041 low = CASE_LOW (gimple_switch_label (stmt, k));
6042 if (!integer_onep (int_const_binop (MINUS_EXPR, low, high, 0)))
6044 take_default = true;
6048 if (CASE_HIGH (gimple_switch_label (stmt, k)))
6049 high = CASE_HIGH (gimple_switch_label (stmt, k));
6054 return !take_default;
6058 /* Visit switch statement STMT. If we can determine which edge
6059 will be taken out of STMT's basic block, record it in
6060 *TAKEN_EDGE_P and return SSA_PROP_INTERESTING. Otherwise, return
6061 SSA_PROP_VARYING. */
6063 static enum ssa_prop_result
6064 vrp_visit_switch_stmt (gimple stmt, edge *taken_edge_p)
6068 size_t i = 0, j = 0;
6071 *taken_edge_p = NULL;
6072 op = gimple_switch_index (stmt);
6073 if (TREE_CODE (op) != SSA_NAME)
6074 return SSA_PROP_VARYING;
6076 vr = get_value_range (op);
6077 if (dump_file && (dump_flags & TDF_DETAILS))
6079 fprintf (dump_file, "\nVisiting switch expression with operand ");
6080 print_generic_expr (dump_file, op, 0);
6081 fprintf (dump_file, " with known range ");
6082 dump_value_range (dump_file, vr);
6083 fprintf (dump_file, "\n");
6086 if (vr->type != VR_RANGE
6087 || symbolic_range_p (vr))
6088 return SSA_PROP_VARYING;
6090 /* Find the single edge that is taken from the switch expression. */
6091 take_default = !find_case_label_range (stmt, vr->min, vr->max, &i, &j);
6093 /* Check if the range spans no CASE_LABEL. If so, we only reach the default
6097 gcc_assert (take_default);
6098 val = gimple_switch_default_label (stmt);
6102 /* Check if labels with index i to j and maybe the default label
6103 are all reaching the same label. */
6105 val = gimple_switch_label (stmt, i);
6107 && CASE_LABEL (gimple_switch_default_label (stmt))
6108 != CASE_LABEL (val))
6110 if (dump_file && (dump_flags & TDF_DETAILS))
6111 fprintf (dump_file, " not a single destination for this "
6113 return SSA_PROP_VARYING;
6115 for (++i; i <= j; ++i)
6117 if (CASE_LABEL (gimple_switch_label (stmt, i)) != CASE_LABEL (val))
6119 if (dump_file && (dump_flags & TDF_DETAILS))
6120 fprintf (dump_file, " not a single destination for this "
6122 return SSA_PROP_VARYING;
6127 *taken_edge_p = find_edge (gimple_bb (stmt),
6128 label_to_block (CASE_LABEL (val)));
6130 if (dump_file && (dump_flags & TDF_DETAILS))
6132 fprintf (dump_file, " will take edge to ");
6133 print_generic_stmt (dump_file, CASE_LABEL (val), 0);
6136 return SSA_PROP_INTERESTING;
6140 /* Evaluate statement STMT. If the statement produces a useful range,
6141 return SSA_PROP_INTERESTING and record the SSA name with the
6142 interesting range into *OUTPUT_P.
6144 If STMT is a conditional branch and we can determine its truth
6145 value, the taken edge is recorded in *TAKEN_EDGE_P.
6147 If STMT produces a varying value, return SSA_PROP_VARYING. */
6149 static enum ssa_prop_result
6150 vrp_visit_stmt (gimple stmt, edge *taken_edge_p, tree *output_p)
6155 if (dump_file && (dump_flags & TDF_DETAILS))
6157 fprintf (dump_file, "\nVisiting statement:\n");
6158 print_gimple_stmt (dump_file, stmt, 0, dump_flags);
6159 fprintf (dump_file, "\n");
6162 if (!stmt_interesting_for_vrp (stmt))
6163 gcc_assert (stmt_ends_bb_p (stmt));
6164 else if (is_gimple_assign (stmt) || is_gimple_call (stmt))
6166 /* In general, assignments with virtual operands are not useful
6167 for deriving ranges, with the obvious exception of calls to
6168 builtin functions. */
6170 if ((is_gimple_call (stmt)
6171 && gimple_call_fndecl (stmt) != NULL_TREE
6172 && DECL_IS_BUILTIN (gimple_call_fndecl (stmt)))
6173 || !gimple_vuse (stmt))
6174 return vrp_visit_assignment_or_call (stmt, output_p);
6176 else if (gimple_code (stmt) == GIMPLE_COND)
6177 return vrp_visit_cond_stmt (stmt, taken_edge_p);
6178 else if (gimple_code (stmt) == GIMPLE_SWITCH)
6179 return vrp_visit_switch_stmt (stmt, taken_edge_p);
6181 /* All other statements produce nothing of interest for VRP, so mark
6182 their outputs varying and prevent further simulation. */
6183 FOR_EACH_SSA_TREE_OPERAND (def, stmt, iter, SSA_OP_DEF)
6184 set_value_range_to_varying (get_value_range (def));
6186 return SSA_PROP_VARYING;
6190 /* Meet operation for value ranges. Given two value ranges VR0 and
6191 VR1, store in VR0 a range that contains both VR0 and VR1. This
6192 may not be the smallest possible such range. */
6195 vrp_meet (value_range_t *vr0, value_range_t *vr1)
6197 if (vr0->type == VR_UNDEFINED)
6199 copy_value_range (vr0, vr1);
6203 if (vr1->type == VR_UNDEFINED)
6205 /* Nothing to do. VR0 already has the resulting range. */
6209 if (vr0->type == VR_VARYING)
6211 /* Nothing to do. VR0 already has the resulting range. */
6215 if (vr1->type == VR_VARYING)
6217 set_value_range_to_varying (vr0);
6221 if (vr0->type == VR_RANGE && vr1->type == VR_RANGE)
6226 /* Compute the convex hull of the ranges. The lower limit of
6227 the new range is the minimum of the two ranges. If they
6228 cannot be compared, then give up. */
6229 cmp = compare_values (vr0->min, vr1->min);
6230 if (cmp == 0 || cmp == 1)
6237 /* Similarly, the upper limit of the new range is the maximum
6238 of the two ranges. If they cannot be compared, then
6240 cmp = compare_values (vr0->max, vr1->max);
6241 if (cmp == 0 || cmp == -1)
6248 /* Check for useless ranges. */
6249 if (INTEGRAL_TYPE_P (TREE_TYPE (min))
6250 && ((vrp_val_is_min (min) || is_overflow_infinity (min))
6251 && (vrp_val_is_max (max) || is_overflow_infinity (max))))
6254 /* The resulting set of equivalences is the intersection of
6256 if (vr0->equiv && vr1->equiv && vr0->equiv != vr1->equiv)
6257 bitmap_and_into (vr0->equiv, vr1->equiv);
6258 else if (vr0->equiv && !vr1->equiv)
6259 bitmap_clear (vr0->equiv);
6261 set_value_range (vr0, vr0->type, min, max, vr0->equiv);
6263 else if (vr0->type == VR_ANTI_RANGE && vr1->type == VR_ANTI_RANGE)
6265 /* Two anti-ranges meet only if their complements intersect.
6266 Only handle the case of identical ranges. */
6267 if (compare_values (vr0->min, vr1->min) == 0
6268 && compare_values (vr0->max, vr1->max) == 0
6269 && compare_values (vr0->min, vr0->max) == 0)
6271 /* The resulting set of equivalences is the intersection of
6273 if (vr0->equiv && vr1->equiv && vr0->equiv != vr1->equiv)
6274 bitmap_and_into (vr0->equiv, vr1->equiv);
6275 else if (vr0->equiv && !vr1->equiv)
6276 bitmap_clear (vr0->equiv);
6281 else if (vr0->type == VR_ANTI_RANGE || vr1->type == VR_ANTI_RANGE)
6283 /* For a numeric range [VAL1, VAL2] and an anti-range ~[VAL3, VAL4],
6284 only handle the case where the ranges have an empty intersection.
6285 The result of the meet operation is the anti-range. */
6286 if (!symbolic_range_p (vr0)
6287 && !symbolic_range_p (vr1)
6288 && !value_ranges_intersect_p (vr0, vr1))
6290 /* Copy most of VR1 into VR0. Don't copy VR1's equivalence
6291 set. We need to compute the intersection of the two
6292 equivalence sets. */
6293 if (vr1->type == VR_ANTI_RANGE)
6294 set_value_range (vr0, vr1->type, vr1->min, vr1->max, vr0->equiv);
6296 /* The resulting set of equivalences is the intersection of
6298 if (vr0->equiv && vr1->equiv && vr0->equiv != vr1->equiv)
6299 bitmap_and_into (vr0->equiv, vr1->equiv);
6300 else if (vr0->equiv && !vr1->equiv)
6301 bitmap_clear (vr0->equiv);
6312 /* Failed to find an efficient meet. Before giving up and setting
6313 the result to VARYING, see if we can at least derive a useful
6314 anti-range. FIXME, all this nonsense about distinguishing
6315 anti-ranges from ranges is necessary because of the odd
6316 semantics of range_includes_zero_p and friends. */
6317 if (!symbolic_range_p (vr0)
6318 && ((vr0->type == VR_RANGE && !range_includes_zero_p (vr0))
6319 || (vr0->type == VR_ANTI_RANGE && range_includes_zero_p (vr0)))
6320 && !symbolic_range_p (vr1)
6321 && ((vr1->type == VR_RANGE && !range_includes_zero_p (vr1))
6322 || (vr1->type == VR_ANTI_RANGE && range_includes_zero_p (vr1))))
6324 set_value_range_to_nonnull (vr0, TREE_TYPE (vr0->min));
6326 /* Since this meet operation did not result from the meeting of
6327 two equivalent names, VR0 cannot have any equivalences. */
6329 bitmap_clear (vr0->equiv);
6332 set_value_range_to_varying (vr0);
6336 /* Visit all arguments for PHI node PHI that flow through executable
6337 edges. If a valid value range can be derived from all the incoming
6338 value ranges, set a new range for the LHS of PHI. */
6340 static enum ssa_prop_result
6341 vrp_visit_phi_node (gimple phi)
6344 tree lhs = PHI_RESULT (phi);
6345 value_range_t *lhs_vr = get_value_range (lhs);
6346 value_range_t vr_result = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
6347 int edges, old_edges;
6350 copy_value_range (&vr_result, lhs_vr);
6352 if (dump_file && (dump_flags & TDF_DETAILS))
6354 fprintf (dump_file, "\nVisiting PHI node: ");
6355 print_gimple_stmt (dump_file, phi, 0, dump_flags);
6359 for (i = 0; i < gimple_phi_num_args (phi); i++)
6361 edge e = gimple_phi_arg_edge (phi, i);
6363 if (dump_file && (dump_flags & TDF_DETAILS))
6366 "\n Argument #%d (%d -> %d %sexecutable)\n",
6367 (int) i, e->src->index, e->dest->index,
6368 (e->flags & EDGE_EXECUTABLE) ? "" : "not ");
6371 if (e->flags & EDGE_EXECUTABLE)
6373 tree arg = PHI_ARG_DEF (phi, i);
6374 value_range_t vr_arg;
6378 if (TREE_CODE (arg) == SSA_NAME)
6380 vr_arg = *(get_value_range (arg));
6384 if (is_overflow_infinity (arg))
6386 arg = copy_node (arg);
6387 TREE_OVERFLOW (arg) = 0;
6390 vr_arg.type = VR_RANGE;
6393 vr_arg.equiv = NULL;
6396 if (dump_file && (dump_flags & TDF_DETAILS))
6398 fprintf (dump_file, "\t");
6399 print_generic_expr (dump_file, arg, dump_flags);
6400 fprintf (dump_file, "\n\tValue: ");
6401 dump_value_range (dump_file, &vr_arg);
6402 fprintf (dump_file, "\n");
6405 vrp_meet (&vr_result, &vr_arg);
6407 if (vr_result.type == VR_VARYING)
6412 /* If this is a loop PHI node SCEV may known more about its
6415 && (l = loop_containing_stmt (phi))
6416 && l->header == gimple_bb (phi))
6417 adjust_range_with_scev (&vr_result, l, phi, lhs);
6419 if (vr_result.type == VR_VARYING)
6422 old_edges = vr_phi_edge_counts[SSA_NAME_VERSION (lhs)];
6423 vr_phi_edge_counts[SSA_NAME_VERSION (lhs)] = edges;
6425 /* To prevent infinite iterations in the algorithm, derive ranges
6426 when the new value is slightly bigger or smaller than the
6427 previous one. We don't do this if we have seen a new executable
6428 edge; this helps us avoid an overflow infinity for conditionals
6429 which are not in a loop. */
6430 if (lhs_vr->type == VR_RANGE && vr_result.type == VR_RANGE
6431 && edges <= old_edges)
6433 if (!POINTER_TYPE_P (TREE_TYPE (lhs)))
6435 int cmp_min = compare_values (lhs_vr->min, vr_result.min);
6436 int cmp_max = compare_values (lhs_vr->max, vr_result.max);
6438 /* If the new minimum is smaller or larger than the previous
6439 one, go all the way to -INF. In the first case, to avoid
6440 iterating millions of times to reach -INF, and in the
6441 other case to avoid infinite bouncing between different
6443 if (cmp_min > 0 || cmp_min < 0)
6445 /* If we will end up with a (-INF, +INF) range, set it to
6446 VARYING. Same if the previous max value was invalid for
6447 the type and we'd end up with vr_result.min > vr_result.max. */
6448 if (vrp_val_is_max (vr_result.max)
6449 || compare_values (TYPE_MIN_VALUE (TREE_TYPE (vr_result.min)),
6453 if (!needs_overflow_infinity (TREE_TYPE (vr_result.min))
6454 || !vrp_var_may_overflow (lhs, phi))
6455 vr_result.min = TYPE_MIN_VALUE (TREE_TYPE (vr_result.min));
6456 else if (supports_overflow_infinity (TREE_TYPE (vr_result.min)))
6458 negative_overflow_infinity (TREE_TYPE (vr_result.min));
6463 /* Similarly, if the new maximum is smaller or larger than
6464 the previous one, go all the way to +INF. */
6465 if (cmp_max < 0 || cmp_max > 0)
6467 /* If we will end up with a (-INF, +INF) range, set it to
6468 VARYING. Same if the previous min value was invalid for
6469 the type and we'd end up with vr_result.max < vr_result.min. */
6470 if (vrp_val_is_min (vr_result.min)
6471 || compare_values (TYPE_MAX_VALUE (TREE_TYPE (vr_result.max)),
6475 if (!needs_overflow_infinity (TREE_TYPE (vr_result.max))
6476 || !vrp_var_may_overflow (lhs, phi))
6477 vr_result.max = TYPE_MAX_VALUE (TREE_TYPE (vr_result.max));
6478 else if (supports_overflow_infinity (TREE_TYPE (vr_result.max)))
6480 positive_overflow_infinity (TREE_TYPE (vr_result.max));
6487 /* If the new range is different than the previous value, keep
6489 if (update_value_range (lhs, &vr_result))
6491 if (dump_file && (dump_flags & TDF_DETAILS))
6493 fprintf (dump_file, "Found new range for ");
6494 print_generic_expr (dump_file, lhs, 0);
6495 fprintf (dump_file, ": ");
6496 dump_value_range (dump_file, &vr_result);
6497 fprintf (dump_file, "\n\n");
6500 return SSA_PROP_INTERESTING;
6503 /* Nothing changed, don't add outgoing edges. */
6504 return SSA_PROP_NOT_INTERESTING;
6506 /* No match found. Set the LHS to VARYING. */
6508 set_value_range_to_varying (lhs_vr);
6509 return SSA_PROP_VARYING;
6512 /* Simplify boolean operations if the source is known
6513 to be already a boolean. */
6515 simplify_truth_ops_using_ranges (gimple_stmt_iterator *gsi, gimple stmt)
6517 enum tree_code rhs_code = gimple_assign_rhs_code (stmt);
6522 bool need_conversion;
6524 op0 = gimple_assign_rhs1 (stmt);
6525 if (TYPE_PRECISION (TREE_TYPE (op0)) != 1)
6527 if (TREE_CODE (op0) != SSA_NAME)
6529 vr = get_value_range (op0);
6531 val = compare_range_with_value (GE_EXPR, vr, integer_zero_node, &sop);
6532 if (!val || !integer_onep (val))
6535 val = compare_range_with_value (LE_EXPR, vr, integer_one_node, &sop);
6536 if (!val || !integer_onep (val))
6540 if (rhs_code == TRUTH_NOT_EXPR)
6543 op1 = build_int_cst (TREE_TYPE (op0), 1);
6547 op1 = gimple_assign_rhs2 (stmt);
6549 /* Reduce number of cases to handle. */
6550 if (is_gimple_min_invariant (op1))
6552 /* Exclude anything that should have been already folded. */
6553 if (rhs_code != EQ_EXPR
6554 && rhs_code != NE_EXPR
6555 && rhs_code != TRUTH_XOR_EXPR)
6558 if (!integer_zerop (op1)
6559 && !integer_onep (op1)
6560 && !integer_all_onesp (op1))
6563 /* Limit the number of cases we have to consider. */
6564 if (rhs_code == EQ_EXPR)
6567 op1 = fold_unary (TRUTH_NOT_EXPR, TREE_TYPE (op1), op1);
6572 /* Punt on A == B as there is no BIT_XNOR_EXPR. */
6573 if (rhs_code == EQ_EXPR)
6576 if (TYPE_PRECISION (TREE_TYPE (op1)) != 1)
6578 vr = get_value_range (op1);
6579 val = compare_range_with_value (GE_EXPR, vr, integer_zero_node, &sop);
6580 if (!val || !integer_onep (val))
6583 val = compare_range_with_value (LE_EXPR, vr, integer_one_node, &sop);
6584 if (!val || !integer_onep (val))
6590 if (sop && issue_strict_overflow_warning (WARN_STRICT_OVERFLOW_MISC))
6592 location_t location;
6594 if (!gimple_has_location (stmt))
6595 location = input_location;
6597 location = gimple_location (stmt);
6599 if (rhs_code == TRUTH_AND_EXPR || rhs_code == TRUTH_OR_EXPR)
6600 warning_at (location, OPT_Wstrict_overflow,
6601 _("assuming signed overflow does not occur when "
6602 "simplifying && or || to & or |"));
6604 warning_at (location, OPT_Wstrict_overflow,
6605 _("assuming signed overflow does not occur when "
6606 "simplifying ==, != or ! to identity or ^"));
6610 !useless_type_conversion_p (TREE_TYPE (gimple_assign_lhs (stmt)),
6613 /* Make sure to not sign-extend -1 as a boolean value. */
6615 && !TYPE_UNSIGNED (TREE_TYPE (op0))
6616 && TYPE_PRECISION (TREE_TYPE (op0)) == 1)
6621 case TRUTH_AND_EXPR:
6622 rhs_code = BIT_AND_EXPR;
6625 rhs_code = BIT_IOR_EXPR;
6627 case TRUTH_XOR_EXPR:
6629 if (integer_zerop (op1))
6631 gimple_assign_set_rhs_with_ops (gsi,
6632 need_conversion ? NOP_EXPR : SSA_NAME,
6634 update_stmt (gsi_stmt (*gsi));
6638 rhs_code = BIT_XOR_EXPR;
6644 if (need_conversion)
6647 gimple_assign_set_rhs_with_ops (gsi, rhs_code, op0, op1);
6648 update_stmt (gsi_stmt (*gsi));
6652 /* Simplify a division or modulo operator to a right shift or
6653 bitwise and if the first operand is unsigned or is greater
6654 than zero and the second operand is an exact power of two. */
6657 simplify_div_or_mod_using_ranges (gimple stmt)
6659 enum tree_code rhs_code = gimple_assign_rhs_code (stmt);
6661 tree op0 = gimple_assign_rhs1 (stmt);
6662 tree op1 = gimple_assign_rhs2 (stmt);
6663 value_range_t *vr = get_value_range (gimple_assign_rhs1 (stmt));
6665 if (TYPE_UNSIGNED (TREE_TYPE (op0)))
6667 val = integer_one_node;
6673 val = compare_range_with_value (GE_EXPR, vr, integer_zero_node, &sop);
6677 && integer_onep (val)
6678 && issue_strict_overflow_warning (WARN_STRICT_OVERFLOW_MISC))
6680 location_t location;
6682 if (!gimple_has_location (stmt))
6683 location = input_location;
6685 location = gimple_location (stmt);
6686 warning_at (location, OPT_Wstrict_overflow,
6687 "assuming signed overflow does not occur when "
6688 "simplifying %</%> or %<%%%> to %<>>%> or %<&%>");
6692 if (val && integer_onep (val))
6696 if (rhs_code == TRUNC_DIV_EXPR)
6698 t = build_int_cst (NULL_TREE, tree_log2 (op1));
6699 gimple_assign_set_rhs_code (stmt, RSHIFT_EXPR);
6700 gimple_assign_set_rhs1 (stmt, op0);
6701 gimple_assign_set_rhs2 (stmt, t);
6705 t = build_int_cst (TREE_TYPE (op1), 1);
6706 t = int_const_binop (MINUS_EXPR, op1, t, 0);
6707 t = fold_convert (TREE_TYPE (op0), t);
6709 gimple_assign_set_rhs_code (stmt, BIT_AND_EXPR);
6710 gimple_assign_set_rhs1 (stmt, op0);
6711 gimple_assign_set_rhs2 (stmt, t);
6721 /* If the operand to an ABS_EXPR is >= 0, then eliminate the
6722 ABS_EXPR. If the operand is <= 0, then simplify the
6723 ABS_EXPR into a NEGATE_EXPR. */
6726 simplify_abs_using_ranges (gimple stmt)
6729 tree op = gimple_assign_rhs1 (stmt);
6730 tree type = TREE_TYPE (op);
6731 value_range_t *vr = get_value_range (op);
6733 if (TYPE_UNSIGNED (type))
6735 val = integer_zero_node;
6741 val = compare_range_with_value (LE_EXPR, vr, integer_zero_node, &sop);
6745 val = compare_range_with_value (GE_EXPR, vr, integer_zero_node,
6750 if (integer_zerop (val))
6751 val = integer_one_node;
6752 else if (integer_onep (val))
6753 val = integer_zero_node;
6758 && (integer_onep (val) || integer_zerop (val)))
6760 if (sop && issue_strict_overflow_warning (WARN_STRICT_OVERFLOW_MISC))
6762 location_t location;
6764 if (!gimple_has_location (stmt))
6765 location = input_location;
6767 location = gimple_location (stmt);
6768 warning_at (location, OPT_Wstrict_overflow,
6769 "assuming signed overflow does not occur when "
6770 "simplifying %<abs (X)%> to %<X%> or %<-X%>");
6773 gimple_assign_set_rhs1 (stmt, op);
6774 if (integer_onep (val))
6775 gimple_assign_set_rhs_code (stmt, NEGATE_EXPR);
6777 gimple_assign_set_rhs_code (stmt, SSA_NAME);
6786 /* We are comparing trees OP0 and OP1 using COND_CODE. OP0 has
6787 a known value range VR.
6789 If there is one and only one value which will satisfy the
6790 conditional, then return that value. Else return NULL. */
6793 test_for_singularity (enum tree_code cond_code, tree op0,
6794 tree op1, value_range_t *vr)
6799 /* Extract minimum/maximum values which satisfy the
6800 the conditional as it was written. */
6801 if (cond_code == LE_EXPR || cond_code == LT_EXPR)
6803 /* This should not be negative infinity; there is no overflow
6805 min = TYPE_MIN_VALUE (TREE_TYPE (op0));
6808 if (cond_code == LT_EXPR && !is_overflow_infinity (max))
6810 tree one = build_int_cst (TREE_TYPE (op0), 1);
6811 max = fold_build2 (MINUS_EXPR, TREE_TYPE (op0), max, one);
6813 TREE_NO_WARNING (max) = 1;
6816 else if (cond_code == GE_EXPR || cond_code == GT_EXPR)
6818 /* This should not be positive infinity; there is no overflow
6820 max = TYPE_MAX_VALUE (TREE_TYPE (op0));
6823 if (cond_code == GT_EXPR && !is_overflow_infinity (min))
6825 tree one = build_int_cst (TREE_TYPE (op0), 1);
6826 min = fold_build2 (PLUS_EXPR, TREE_TYPE (op0), min, one);
6828 TREE_NO_WARNING (min) = 1;
6832 /* Now refine the minimum and maximum values using any
6833 value range information we have for op0. */
6836 if (compare_values (vr->min, min) == 1)
6838 if (compare_values (vr->max, max) == -1)
6841 /* If the new min/max values have converged to a single value,
6842 then there is only one value which can satisfy the condition,
6843 return that value. */
6844 if (operand_equal_p (min, max, 0) && is_gimple_min_invariant (min))
6850 /* Simplify a conditional using a relational operator to an equality
6851 test if the range information indicates only one value can satisfy
6852 the original conditional. */
6855 simplify_cond_using_ranges (gimple stmt)
6857 tree op0 = gimple_cond_lhs (stmt);
6858 tree op1 = gimple_cond_rhs (stmt);
6859 enum tree_code cond_code = gimple_cond_code (stmt);
6861 if (cond_code != NE_EXPR
6862 && cond_code != EQ_EXPR
6863 && TREE_CODE (op0) == SSA_NAME
6864 && INTEGRAL_TYPE_P (TREE_TYPE (op0))
6865 && is_gimple_min_invariant (op1))
6867 value_range_t *vr = get_value_range (op0);
6869 /* If we have range information for OP0, then we might be
6870 able to simplify this conditional. */
6871 if (vr->type == VR_RANGE)
6873 tree new_tree = test_for_singularity (cond_code, op0, op1, vr);
6879 fprintf (dump_file, "Simplified relational ");
6880 print_gimple_stmt (dump_file, stmt, 0, 0);
6881 fprintf (dump_file, " into ");
6884 gimple_cond_set_code (stmt, EQ_EXPR);
6885 gimple_cond_set_lhs (stmt, op0);
6886 gimple_cond_set_rhs (stmt, new_tree);
6892 print_gimple_stmt (dump_file, stmt, 0, 0);
6893 fprintf (dump_file, "\n");
6899 /* Try again after inverting the condition. We only deal
6900 with integral types here, so no need to worry about
6901 issues with inverting FP comparisons. */
6902 cond_code = invert_tree_comparison (cond_code, false);
6903 new_tree = test_for_singularity (cond_code, op0, op1, vr);
6909 fprintf (dump_file, "Simplified relational ");
6910 print_gimple_stmt (dump_file, stmt, 0, 0);
6911 fprintf (dump_file, " into ");
6914 gimple_cond_set_code (stmt, NE_EXPR);
6915 gimple_cond_set_lhs (stmt, op0);
6916 gimple_cond_set_rhs (stmt, new_tree);
6922 print_gimple_stmt (dump_file, stmt, 0, 0);
6923 fprintf (dump_file, "\n");
6934 /* Simplify a switch statement using the value range of the switch
6938 simplify_switch_using_ranges (gimple stmt)
6940 tree op = gimple_switch_index (stmt);
6945 size_t i = 0, j = 0, n, n2;
6949 if (TREE_CODE (op) == SSA_NAME)
6951 vr = get_value_range (op);
6953 /* We can only handle integer ranges. */
6954 if (vr->type != VR_RANGE
6955 || symbolic_range_p (vr))
6958 /* Find case label for min/max of the value range. */
6959 take_default = !find_case_label_range (stmt, vr->min, vr->max, &i, &j);
6961 else if (TREE_CODE (op) == INTEGER_CST)
6963 take_default = !find_case_label_index (stmt, 1, op, &i);
6977 n = gimple_switch_num_labels (stmt);
6979 /* Bail out if this is just all edges taken. */
6985 /* Build a new vector of taken case labels. */
6986 vec2 = make_tree_vec (j - i + 1 + (int)take_default);
6989 /* Add the default edge, if necessary. */
6991 TREE_VEC_ELT (vec2, n2++) = gimple_switch_default_label (stmt);
6993 for (; i <= j; ++i, ++n2)
6994 TREE_VEC_ELT (vec2, n2) = gimple_switch_label (stmt, i);
6996 /* Mark needed edges. */
6997 for (i = 0; i < n2; ++i)
6999 e = find_edge (gimple_bb (stmt),
7000 label_to_block (CASE_LABEL (TREE_VEC_ELT (vec2, i))));
7001 e->aux = (void *)-1;
7004 /* Queue not needed edges for later removal. */
7005 FOR_EACH_EDGE (e, ei, gimple_bb (stmt)->succs)
7007 if (e->aux == (void *)-1)
7013 if (dump_file && (dump_flags & TDF_DETAILS))
7015 fprintf (dump_file, "removing unreachable case label\n");
7017 VEC_safe_push (edge, heap, to_remove_edges, e);
7018 e->flags &= ~EDGE_EXECUTABLE;
7021 /* And queue an update for the stmt. */
7024 VEC_safe_push (switch_update, heap, to_update_switch_stmts, &su);
7028 /* Simplify STMT using ranges if possible. */
7031 simplify_stmt_using_ranges (gimple_stmt_iterator *gsi)
7033 gimple stmt = gsi_stmt (*gsi);
7034 if (is_gimple_assign (stmt))
7036 enum tree_code rhs_code = gimple_assign_rhs_code (stmt);
7042 case TRUTH_NOT_EXPR:
7043 case TRUTH_AND_EXPR:
7045 case TRUTH_XOR_EXPR:
7046 /* Transform EQ_EXPR, NE_EXPR, TRUTH_NOT_EXPR into BIT_XOR_EXPR
7047 or identity if the RHS is zero or one, and the LHS are known
7048 to be boolean values. Transform all TRUTH_*_EXPR into
7049 BIT_*_EXPR if both arguments are known to be boolean values. */
7050 if (INTEGRAL_TYPE_P (TREE_TYPE (gimple_assign_rhs1 (stmt))))
7051 return simplify_truth_ops_using_ranges (gsi, stmt);
7054 /* Transform TRUNC_DIV_EXPR and TRUNC_MOD_EXPR into RSHIFT_EXPR
7055 and BIT_AND_EXPR respectively if the first operand is greater
7056 than zero and the second operand is an exact power of two. */
7057 case TRUNC_DIV_EXPR:
7058 case TRUNC_MOD_EXPR:
7059 if (INTEGRAL_TYPE_P (TREE_TYPE (gimple_assign_rhs1 (stmt)))
7060 && integer_pow2p (gimple_assign_rhs2 (stmt)))
7061 return simplify_div_or_mod_using_ranges (stmt);
7064 /* Transform ABS (X) into X or -X as appropriate. */
7066 if (TREE_CODE (gimple_assign_rhs1 (stmt)) == SSA_NAME
7067 && INTEGRAL_TYPE_P (TREE_TYPE (gimple_assign_rhs1 (stmt))))
7068 return simplify_abs_using_ranges (stmt);
7075 else if (gimple_code (stmt) == GIMPLE_COND)
7076 return simplify_cond_using_ranges (stmt);
7077 else if (gimple_code (stmt) == GIMPLE_SWITCH)
7078 return simplify_switch_using_ranges (stmt);
7083 /* If the statement pointed by SI has a predicate whose value can be
7084 computed using the value range information computed by VRP, compute
7085 its value and return true. Otherwise, return false. */
7088 fold_predicate_in (gimple_stmt_iterator *si)
7090 bool assignment_p = false;
7092 gimple stmt = gsi_stmt (*si);
7094 if (is_gimple_assign (stmt)
7095 && TREE_CODE_CLASS (gimple_assign_rhs_code (stmt)) == tcc_comparison)
7097 assignment_p = true;
7098 val = vrp_evaluate_conditional (gimple_assign_rhs_code (stmt),
7099 gimple_assign_rhs1 (stmt),
7100 gimple_assign_rhs2 (stmt),
7103 else if (gimple_code (stmt) == GIMPLE_COND)
7104 val = vrp_evaluate_conditional (gimple_cond_code (stmt),
7105 gimple_cond_lhs (stmt),
7106 gimple_cond_rhs (stmt),
7114 val = fold_convert (gimple_expr_type (stmt), val);
7118 fprintf (dump_file, "Folding predicate ");
7119 print_gimple_expr (dump_file, stmt, 0, 0);
7120 fprintf (dump_file, " to ");
7121 print_generic_expr (dump_file, val, 0);
7122 fprintf (dump_file, "\n");
7125 if (is_gimple_assign (stmt))
7126 gimple_assign_set_rhs_from_tree (si, val);
7129 gcc_assert (gimple_code (stmt) == GIMPLE_COND);
7130 if (integer_zerop (val))
7131 gimple_cond_make_false (stmt);
7132 else if (integer_onep (val))
7133 gimple_cond_make_true (stmt);
7144 /* Callback for substitute_and_fold folding the stmt at *SI. */
7147 vrp_fold_stmt (gimple_stmt_iterator *si)
7149 if (fold_predicate_in (si))
7152 return simplify_stmt_using_ranges (si);
7155 /* Stack of dest,src equivalency pairs that need to be restored after
7156 each attempt to thread a block's incoming edge to an outgoing edge.
7158 A NULL entry is used to mark the end of pairs which need to be
7160 static VEC(tree,heap) *stack;
7162 /* A trivial wrapper so that we can present the generic jump threading
7163 code with a simple API for simplifying statements. STMT is the
7164 statement we want to simplify, WITHIN_STMT provides the location
7165 for any overflow warnings. */
7168 simplify_stmt_for_jump_threading (gimple stmt, gimple within_stmt)
7170 /* We only use VRP information to simplify conditionals. This is
7171 overly conservative, but it's unclear if doing more would be
7172 worth the compile time cost. */
7173 if (gimple_code (stmt) != GIMPLE_COND)
7176 return vrp_evaluate_conditional (gimple_cond_code (stmt),
7177 gimple_cond_lhs (stmt),
7178 gimple_cond_rhs (stmt), within_stmt);
7181 /* Blocks which have more than one predecessor and more than
7182 one successor present jump threading opportunities, i.e.,
7183 when the block is reached from a specific predecessor, we
7184 may be able to determine which of the outgoing edges will
7185 be traversed. When this optimization applies, we are able
7186 to avoid conditionals at runtime and we may expose secondary
7187 optimization opportunities.
7189 This routine is effectively a driver for the generic jump
7190 threading code. It basically just presents the generic code
7191 with edges that may be suitable for jump threading.
7193 Unlike DOM, we do not iterate VRP if jump threading was successful.
7194 While iterating may expose new opportunities for VRP, it is expected
7195 those opportunities would be very limited and the compile time cost
7196 to expose those opportunities would be significant.
7198 As jump threading opportunities are discovered, they are registered
7199 for later realization. */
7202 identify_jump_threads (void)
7209 /* Ugh. When substituting values earlier in this pass we can
7210 wipe the dominance information. So rebuild the dominator
7211 information as we need it within the jump threading code. */
7212 calculate_dominance_info (CDI_DOMINATORS);
7214 /* We do not allow VRP information to be used for jump threading
7215 across a back edge in the CFG. Otherwise it becomes too
7216 difficult to avoid eliminating loop exit tests. Of course
7217 EDGE_DFS_BACK is not accurate at this time so we have to
7219 mark_dfs_back_edges ();
7221 /* Do not thread across edges we are about to remove. Just marking
7222 them as EDGE_DFS_BACK will do. */
7223 for (i = 0; VEC_iterate (edge, to_remove_edges, i, e); ++i)
7224 e->flags |= EDGE_DFS_BACK;
7226 /* Allocate our unwinder stack to unwind any temporary equivalences
7227 that might be recorded. */
7228 stack = VEC_alloc (tree, heap, 20);
7230 /* To avoid lots of silly node creation, we create a single
7231 conditional and just modify it in-place when attempting to
7233 dummy = gimple_build_cond (EQ_EXPR,
7234 integer_zero_node, integer_zero_node,
7237 /* Walk through all the blocks finding those which present a
7238 potential jump threading opportunity. We could set this up
7239 as a dominator walker and record data during the walk, but
7240 I doubt it's worth the effort for the classes of jump
7241 threading opportunities we are trying to identify at this
7242 point in compilation. */
7247 /* If the generic jump threading code does not find this block
7248 interesting, then there is nothing to do. */
7249 if (! potentially_threadable_block (bb))
7252 /* We only care about blocks ending in a COND_EXPR. While there
7253 may be some value in handling SWITCH_EXPR here, I doubt it's
7254 terribly important. */
7255 last = gsi_stmt (gsi_last_bb (bb));
7256 if (gimple_code (last) != GIMPLE_COND)
7259 /* We're basically looking for any kind of conditional with
7260 integral type arguments. */
7261 if (TREE_CODE (gimple_cond_lhs (last)) == SSA_NAME
7262 && INTEGRAL_TYPE_P (TREE_TYPE (gimple_cond_lhs (last)))
7263 && (TREE_CODE (gimple_cond_rhs (last)) == SSA_NAME
7264 || is_gimple_min_invariant (gimple_cond_rhs (last)))
7265 && INTEGRAL_TYPE_P (TREE_TYPE (gimple_cond_rhs (last))))
7269 /* We've got a block with multiple predecessors and multiple
7270 successors which also ends in a suitable conditional. For
7271 each predecessor, see if we can thread it to a specific
7273 FOR_EACH_EDGE (e, ei, bb->preds)
7275 /* Do not thread across back edges or abnormal edges
7277 if (e->flags & (EDGE_DFS_BACK | EDGE_COMPLEX))
7280 thread_across_edge (dummy, e, true, &stack,
7281 simplify_stmt_for_jump_threading);
7286 /* We do not actually update the CFG or SSA graphs at this point as
7287 ASSERT_EXPRs are still in the IL and cfg cleanup code does not yet
7288 handle ASSERT_EXPRs gracefully. */
7291 /* We identified all the jump threading opportunities earlier, but could
7292 not transform the CFG at that time. This routine transforms the
7293 CFG and arranges for the dominator tree to be rebuilt if necessary.
7295 Note the SSA graph update will occur during the normal TODO
7296 processing by the pass manager. */
7298 finalize_jump_threads (void)
7300 thread_through_all_blocks (false);
7301 VEC_free (tree, heap, stack);
7305 /* Traverse all the blocks folding conditionals with known ranges. */
7311 prop_value_t *single_val_range;
7312 bool do_value_subst_p;
7316 fprintf (dump_file, "\nValue ranges after VRP:\n\n");
7317 dump_all_value_ranges (dump_file);
7318 fprintf (dump_file, "\n");
7321 /* We may have ended with ranges that have exactly one value. Those
7322 values can be substituted as any other const propagated
7323 value using substitute_and_fold. */
7324 single_val_range = XCNEWVEC (prop_value_t, num_ssa_names);
7326 do_value_subst_p = false;
7327 for (i = 0; i < num_ssa_names; i++)
7329 && vr_value[i]->type == VR_RANGE
7330 && vr_value[i]->min == vr_value[i]->max
7331 && is_gimple_min_invariant (vr_value[i]->min))
7333 single_val_range[i].value = vr_value[i]->min;
7334 do_value_subst_p = true;
7337 if (!do_value_subst_p)
7339 /* We found no single-valued ranges, don't waste time trying to
7340 do single value substitution in substitute_and_fold. */
7341 free (single_val_range);
7342 single_val_range = NULL;
7345 substitute_and_fold (single_val_range, vrp_fold_stmt);
7347 if (warn_array_bounds)
7348 check_all_array_refs ();
7350 /* We must identify jump threading opportunities before we release
7351 the datastructures built by VRP. */
7352 identify_jump_threads ();
7354 /* Free allocated memory. */
7355 for (i = 0; i < num_ssa_names; i++)
7358 BITMAP_FREE (vr_value[i]->equiv);
7362 free (single_val_range);
7364 free (vr_phi_edge_counts);
7366 /* So that we can distinguish between VRP data being available
7367 and not available. */
7369 vr_phi_edge_counts = NULL;
7373 /* Main entry point to VRP (Value Range Propagation). This pass is
7374 loosely based on J. R. C. Patterson, ``Accurate Static Branch
7375 Prediction by Value Range Propagation,'' in SIGPLAN Conference on
7376 Programming Language Design and Implementation, pp. 67-78, 1995.
7377 Also available at http://citeseer.ist.psu.edu/patterson95accurate.html
7379 This is essentially an SSA-CCP pass modified to deal with ranges
7380 instead of constants.
7382 While propagating ranges, we may find that two or more SSA name
7383 have equivalent, though distinct ranges. For instance,
7386 2 p_4 = ASSERT_EXPR <p_3, p_3 != 0>
7388 4 p_5 = ASSERT_EXPR <p_4, p_4 == q_2>;
7392 In the code above, pointer p_5 has range [q_2, q_2], but from the
7393 code we can also determine that p_5 cannot be NULL and, if q_2 had
7394 a non-varying range, p_5's range should also be compatible with it.
7396 These equivalences are created by two expressions: ASSERT_EXPR and
7397 copy operations. Since p_5 is an assertion on p_4, and p_4 was the
7398 result of another assertion, then we can use the fact that p_5 and
7399 p_4 are equivalent when evaluating p_5's range.
7401 Together with value ranges, we also propagate these equivalences
7402 between names so that we can take advantage of information from
7403 multiple ranges when doing final replacement. Note that this
7404 equivalency relation is transitive but not symmetric.
7406 In the example above, p_5 is equivalent to p_4, q_2 and p_3, but we
7407 cannot assert that q_2 is equivalent to p_5 because q_2 may be used
7408 in contexts where that assertion does not hold (e.g., in line 6).
7410 TODO, the main difference between this pass and Patterson's is that
7411 we do not propagate edge probabilities. We only compute whether
7412 edges can be taken or not. That is, instead of having a spectrum
7413 of jump probabilities between 0 and 1, we only deal with 0, 1 and
7414 DON'T KNOW. In the future, it may be worthwhile to propagate
7415 probabilities to aid branch prediction. */
7424 loop_optimizer_init (LOOPS_NORMAL | LOOPS_HAVE_RECORDED_EXITS);
7425 rewrite_into_loop_closed_ssa (NULL, TODO_update_ssa);
7428 insert_range_assertions ();
7430 to_remove_edges = VEC_alloc (edge, heap, 10);
7431 to_update_switch_stmts = VEC_alloc (switch_update, heap, 5);
7432 threadedge_initialize_values ();
7435 ssa_propagate (vrp_visit_stmt, vrp_visit_phi_node);
7438 /* ASSERT_EXPRs must be removed before finalizing jump threads
7439 as finalizing jump threads calls the CFG cleanup code which
7440 does not properly handle ASSERT_EXPRs. */
7441 remove_range_assertions ();
7443 /* If we exposed any new variables, go ahead and put them into
7444 SSA form now, before we handle jump threading. This simplifies
7445 interactions between rewriting of _DECL nodes into SSA form
7446 and rewriting SSA_NAME nodes into SSA form after block
7447 duplication and CFG manipulation. */
7448 update_ssa (TODO_update_ssa);
7450 finalize_jump_threads ();
7452 /* Remove dead edges from SWITCH_EXPR optimization. This leaves the
7453 CFG in a broken state and requires a cfg_cleanup run. */
7454 for (i = 0; VEC_iterate (edge, to_remove_edges, i, e); ++i)
7456 /* Update SWITCH_EXPR case label vector. */
7457 for (i = 0; VEC_iterate (switch_update, to_update_switch_stmts, i, su); ++i)
7460 size_t n = TREE_VEC_LENGTH (su->vec);
7462 gimple_switch_set_num_labels (su->stmt, n);
7463 for (j = 0; j < n; j++)
7464 gimple_switch_set_label (su->stmt, j, TREE_VEC_ELT (su->vec, j));
7465 /* As we may have replaced the default label with a regular one
7466 make sure to make it a real default label again. This ensures
7467 optimal expansion. */
7468 label = gimple_switch_default_label (su->stmt);
7469 CASE_LOW (label) = NULL_TREE;
7470 CASE_HIGH (label) = NULL_TREE;
7473 if (VEC_length (edge, to_remove_edges) > 0)
7474 free_dominance_info (CDI_DOMINATORS);
7476 VEC_free (edge, heap, to_remove_edges);
7477 VEC_free (switch_update, heap, to_update_switch_stmts);
7478 threadedge_finalize_values ();
7481 loop_optimizer_finalize ();
7488 return flag_tree_vrp != 0;
7491 struct gimple_opt_pass pass_vrp =
7496 gate_vrp, /* gate */
7497 execute_vrp, /* execute */
7500 0, /* static_pass_number */
7501 TV_TREE_VRP, /* tv_id */
7502 PROP_ssa, /* properties_required */
7503 0, /* properties_provided */
7504 0, /* properties_destroyed */
7505 0, /* todo_flags_start */
7510 | TODO_update_ssa /* todo_flags_finish */