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);
768 /* Return true if value range VR involves at least one symbol. */
771 symbolic_range_p (value_range_t *vr)
773 return (!is_gimple_min_invariant (vr->min)
774 || !is_gimple_min_invariant (vr->max));
777 /* Return true if value range VR uses an overflow infinity. */
780 overflow_infinity_range_p (value_range_t *vr)
782 return (vr->type == VR_RANGE
783 && (is_overflow_infinity (vr->min)
784 || is_overflow_infinity (vr->max)));
787 /* Return false if we can not make a valid comparison based on VR;
788 this will be the case if it uses an overflow infinity and overflow
789 is not undefined (i.e., -fno-strict-overflow is in effect).
790 Otherwise return true, and set *STRICT_OVERFLOW_P to true if VR
791 uses an overflow infinity. */
794 usable_range_p (value_range_t *vr, bool *strict_overflow_p)
796 gcc_assert (vr->type == VR_RANGE);
797 if (is_overflow_infinity (vr->min))
799 *strict_overflow_p = true;
800 if (!TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (vr->min)))
803 if (is_overflow_infinity (vr->max))
805 *strict_overflow_p = true;
806 if (!TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (vr->max)))
813 /* Like tree_expr_nonnegative_warnv_p, but this function uses value
814 ranges obtained so far. */
817 vrp_expr_computes_nonnegative (tree expr, bool *strict_overflow_p)
819 return (tree_expr_nonnegative_warnv_p (expr, strict_overflow_p)
820 || (TREE_CODE (expr) == SSA_NAME
821 && ssa_name_nonnegative_p (expr)));
824 /* Return true if the result of assignment STMT is know to be non-negative.
825 If the return value is based on the assumption that signed overflow is
826 undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't change
827 *STRICT_OVERFLOW_P.*/
830 gimple_assign_nonnegative_warnv_p (gimple stmt, bool *strict_overflow_p)
832 enum tree_code code = gimple_assign_rhs_code (stmt);
833 switch (get_gimple_rhs_class (code))
835 case GIMPLE_UNARY_RHS:
836 return tree_unary_nonnegative_warnv_p (gimple_assign_rhs_code (stmt),
837 gimple_expr_type (stmt),
838 gimple_assign_rhs1 (stmt),
840 case GIMPLE_BINARY_RHS:
841 return tree_binary_nonnegative_warnv_p (gimple_assign_rhs_code (stmt),
842 gimple_expr_type (stmt),
843 gimple_assign_rhs1 (stmt),
844 gimple_assign_rhs2 (stmt),
846 case GIMPLE_SINGLE_RHS:
847 return tree_single_nonnegative_warnv_p (gimple_assign_rhs1 (stmt),
849 case GIMPLE_INVALID_RHS:
856 /* Return true if return value of call STMT is know to be non-negative.
857 If the return value is based on the assumption that signed overflow is
858 undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't change
859 *STRICT_OVERFLOW_P.*/
862 gimple_call_nonnegative_warnv_p (gimple stmt, bool *strict_overflow_p)
864 tree arg0 = gimple_call_num_args (stmt) > 0 ?
865 gimple_call_arg (stmt, 0) : NULL_TREE;
866 tree arg1 = gimple_call_num_args (stmt) > 1 ?
867 gimple_call_arg (stmt, 1) : NULL_TREE;
869 return tree_call_nonnegative_warnv_p (gimple_expr_type (stmt),
870 gimple_call_fndecl (stmt),
876 /* Return true if STMT is know to to compute a non-negative value.
877 If the return value is based on the assumption that signed overflow is
878 undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't change
879 *STRICT_OVERFLOW_P.*/
882 gimple_stmt_nonnegative_warnv_p (gimple stmt, bool *strict_overflow_p)
884 switch (gimple_code (stmt))
887 return gimple_assign_nonnegative_warnv_p (stmt, strict_overflow_p);
889 return gimple_call_nonnegative_warnv_p (stmt, strict_overflow_p);
895 /* Return true if the result of assignment STMT is know to be non-zero.
896 If the return value is based on the assumption that signed overflow is
897 undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't change
898 *STRICT_OVERFLOW_P.*/
901 gimple_assign_nonzero_warnv_p (gimple stmt, bool *strict_overflow_p)
903 enum tree_code code = gimple_assign_rhs_code (stmt);
904 switch (get_gimple_rhs_class (code))
906 case GIMPLE_UNARY_RHS:
907 return tree_unary_nonzero_warnv_p (gimple_assign_rhs_code (stmt),
908 gimple_expr_type (stmt),
909 gimple_assign_rhs1 (stmt),
911 case GIMPLE_BINARY_RHS:
912 return tree_binary_nonzero_warnv_p (gimple_assign_rhs_code (stmt),
913 gimple_expr_type (stmt),
914 gimple_assign_rhs1 (stmt),
915 gimple_assign_rhs2 (stmt),
917 case GIMPLE_SINGLE_RHS:
918 return tree_single_nonzero_warnv_p (gimple_assign_rhs1 (stmt),
920 case GIMPLE_INVALID_RHS:
927 /* Return true if STMT is know to to compute a non-zero value.
928 If the return value is based on the assumption that signed overflow is
929 undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't change
930 *STRICT_OVERFLOW_P.*/
933 gimple_stmt_nonzero_warnv_p (gimple stmt, bool *strict_overflow_p)
935 switch (gimple_code (stmt))
938 return gimple_assign_nonzero_warnv_p (stmt, strict_overflow_p);
940 return gimple_alloca_call_p (stmt);
946 /* Like tree_expr_nonzero_warnv_p, but this function uses value ranges
950 vrp_stmt_computes_nonzero (gimple stmt, bool *strict_overflow_p)
952 if (gimple_stmt_nonzero_warnv_p (stmt, strict_overflow_p))
955 /* If we have an expression of the form &X->a, then the expression
956 is nonnull if X is nonnull. */
957 if (is_gimple_assign (stmt)
958 && gimple_assign_rhs_code (stmt) == ADDR_EXPR)
960 tree expr = gimple_assign_rhs1 (stmt);
961 tree base = get_base_address (TREE_OPERAND (expr, 0));
963 if (base != NULL_TREE
964 && TREE_CODE (base) == INDIRECT_REF
965 && TREE_CODE (TREE_OPERAND (base, 0)) == SSA_NAME)
967 value_range_t *vr = get_value_range (TREE_OPERAND (base, 0));
968 if (range_is_nonnull (vr))
976 /* Returns true if EXPR is a valid value (as expected by compare_values) --
977 a gimple invariant, or SSA_NAME +- CST. */
980 valid_value_p (tree expr)
982 if (TREE_CODE (expr) == SSA_NAME)
985 if (TREE_CODE (expr) == PLUS_EXPR
986 || TREE_CODE (expr) == MINUS_EXPR)
987 return (TREE_CODE (TREE_OPERAND (expr, 0)) == SSA_NAME
988 && TREE_CODE (TREE_OPERAND (expr, 1)) == INTEGER_CST);
990 return is_gimple_min_invariant (expr);
996 -2 if those are incomparable. */
998 operand_less_p (tree val, tree val2)
1000 /* LT is folded faster than GE and others. Inline the common case. */
1001 if (TREE_CODE (val) == INTEGER_CST && TREE_CODE (val2) == INTEGER_CST)
1003 if (TYPE_UNSIGNED (TREE_TYPE (val)))
1004 return INT_CST_LT_UNSIGNED (val, val2);
1007 if (INT_CST_LT (val, val2))
1015 fold_defer_overflow_warnings ();
1017 tcmp = fold_binary_to_constant (LT_EXPR, boolean_type_node, val, val2);
1019 fold_undefer_and_ignore_overflow_warnings ();
1022 || TREE_CODE (tcmp) != INTEGER_CST)
1025 if (!integer_zerop (tcmp))
1029 /* val >= val2, not considering overflow infinity. */
1030 if (is_negative_overflow_infinity (val))
1031 return is_negative_overflow_infinity (val2) ? 0 : 1;
1032 else if (is_positive_overflow_infinity (val2))
1033 return is_positive_overflow_infinity (val) ? 0 : 1;
1038 /* Compare two values VAL1 and VAL2. Return
1040 -2 if VAL1 and VAL2 cannot be compared at compile-time,
1043 +1 if VAL1 > VAL2, and
1046 This is similar to tree_int_cst_compare but supports pointer values
1047 and values that cannot be compared at compile time.
1049 If STRICT_OVERFLOW_P is not NULL, then set *STRICT_OVERFLOW_P to
1050 true if the return value is only valid if we assume that signed
1051 overflow is undefined. */
1054 compare_values_warnv (tree val1, tree val2, bool *strict_overflow_p)
1059 /* Below we rely on the fact that VAL1 and VAL2 are both pointers or
1061 gcc_assert (POINTER_TYPE_P (TREE_TYPE (val1))
1062 == POINTER_TYPE_P (TREE_TYPE (val2)));
1063 /* Convert the two values into the same type. This is needed because
1064 sizetype causes sign extension even for unsigned types. */
1065 val2 = fold_convert (TREE_TYPE (val1), val2);
1066 STRIP_USELESS_TYPE_CONVERSION (val2);
1068 if ((TREE_CODE (val1) == SSA_NAME
1069 || TREE_CODE (val1) == PLUS_EXPR
1070 || TREE_CODE (val1) == MINUS_EXPR)
1071 && (TREE_CODE (val2) == SSA_NAME
1072 || TREE_CODE (val2) == PLUS_EXPR
1073 || TREE_CODE (val2) == MINUS_EXPR))
1075 tree n1, c1, n2, c2;
1076 enum tree_code code1, code2;
1078 /* If VAL1 and VAL2 are of the form 'NAME [+-] CST' or 'NAME',
1079 return -1 or +1 accordingly. If VAL1 and VAL2 don't use the
1080 same name, return -2. */
1081 if (TREE_CODE (val1) == SSA_NAME)
1089 code1 = TREE_CODE (val1);
1090 n1 = TREE_OPERAND (val1, 0);
1091 c1 = TREE_OPERAND (val1, 1);
1092 if (tree_int_cst_sgn (c1) == -1)
1094 if (is_negative_overflow_infinity (c1))
1096 c1 = fold_unary_to_constant (NEGATE_EXPR, TREE_TYPE (c1), c1);
1099 code1 = code1 == MINUS_EXPR ? PLUS_EXPR : MINUS_EXPR;
1103 if (TREE_CODE (val2) == SSA_NAME)
1111 code2 = TREE_CODE (val2);
1112 n2 = TREE_OPERAND (val2, 0);
1113 c2 = TREE_OPERAND (val2, 1);
1114 if (tree_int_cst_sgn (c2) == -1)
1116 if (is_negative_overflow_infinity (c2))
1118 c2 = fold_unary_to_constant (NEGATE_EXPR, TREE_TYPE (c2), c2);
1121 code2 = code2 == MINUS_EXPR ? PLUS_EXPR : MINUS_EXPR;
1125 /* Both values must use the same name. */
1129 if (code1 == SSA_NAME
1130 && code2 == SSA_NAME)
1134 /* If overflow is defined we cannot simplify more. */
1135 if (!TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (val1)))
1138 if (strict_overflow_p != NULL
1139 && (code1 == SSA_NAME || !TREE_NO_WARNING (val1))
1140 && (code2 == SSA_NAME || !TREE_NO_WARNING (val2)))
1141 *strict_overflow_p = true;
1143 if (code1 == SSA_NAME)
1145 if (code2 == PLUS_EXPR)
1146 /* NAME < NAME + CST */
1148 else if (code2 == MINUS_EXPR)
1149 /* NAME > NAME - CST */
1152 else if (code1 == PLUS_EXPR)
1154 if (code2 == SSA_NAME)
1155 /* NAME + CST > NAME */
1157 else if (code2 == PLUS_EXPR)
1158 /* NAME + CST1 > NAME + CST2, if CST1 > CST2 */
1159 return compare_values_warnv (c1, c2, strict_overflow_p);
1160 else if (code2 == MINUS_EXPR)
1161 /* NAME + CST1 > NAME - CST2 */
1164 else if (code1 == MINUS_EXPR)
1166 if (code2 == SSA_NAME)
1167 /* NAME - CST < NAME */
1169 else if (code2 == PLUS_EXPR)
1170 /* NAME - CST1 < NAME + CST2 */
1172 else if (code2 == MINUS_EXPR)
1173 /* NAME - CST1 > NAME - CST2, if CST1 < CST2. Notice that
1174 C1 and C2 are swapped in the call to compare_values. */
1175 return compare_values_warnv (c2, c1, strict_overflow_p);
1181 /* We cannot compare non-constants. */
1182 if (!is_gimple_min_invariant (val1) || !is_gimple_min_invariant (val2))
1185 if (!POINTER_TYPE_P (TREE_TYPE (val1)))
1187 /* We cannot compare overflowed values, except for overflow
1189 if (TREE_OVERFLOW (val1) || TREE_OVERFLOW (val2))
1191 if (strict_overflow_p != NULL)
1192 *strict_overflow_p = true;
1193 if (is_negative_overflow_infinity (val1))
1194 return is_negative_overflow_infinity (val2) ? 0 : -1;
1195 else if (is_negative_overflow_infinity (val2))
1197 else if (is_positive_overflow_infinity (val1))
1198 return is_positive_overflow_infinity (val2) ? 0 : 1;
1199 else if (is_positive_overflow_infinity (val2))
1204 return tree_int_cst_compare (val1, val2);
1210 /* First see if VAL1 and VAL2 are not the same. */
1211 if (val1 == val2 || operand_equal_p (val1, val2, 0))
1214 /* If VAL1 is a lower address than VAL2, return -1. */
1215 if (operand_less_p (val1, val2) == 1)
1218 /* If VAL1 is a higher address than VAL2, return +1. */
1219 if (operand_less_p (val2, val1) == 1)
1222 /* If VAL1 is different than VAL2, return +2.
1223 For integer constants we either have already returned -1 or 1
1224 or they are equivalent. We still might succeed in proving
1225 something about non-trivial operands. */
1226 if (TREE_CODE (val1) != INTEGER_CST
1227 || TREE_CODE (val2) != INTEGER_CST)
1229 t = fold_binary_to_constant (NE_EXPR, boolean_type_node, val1, val2);
1230 if (t && integer_onep (t))
1238 /* Compare values like compare_values_warnv, but treat comparisons of
1239 nonconstants which rely on undefined overflow as incomparable. */
1242 compare_values (tree val1, tree val2)
1248 ret = compare_values_warnv (val1, val2, &sop);
1250 && (!is_gimple_min_invariant (val1) || !is_gimple_min_invariant (val2)))
1256 /* Return 1 if VAL is inside value range VR (VR->MIN <= VAL <= VR->MAX),
1257 0 if VAL is not inside VR,
1258 -2 if we cannot tell either way.
1260 FIXME, the current semantics of this functions are a bit quirky
1261 when taken in the context of VRP. In here we do not care
1262 about VR's type. If VR is the anti-range ~[3, 5] the call
1263 value_inside_range (4, VR) will return 1.
1265 This is counter-intuitive in a strict sense, but the callers
1266 currently expect this. They are calling the function
1267 merely to determine whether VR->MIN <= VAL <= VR->MAX. The
1268 callers are applying the VR_RANGE/VR_ANTI_RANGE semantics
1271 This also applies to value_ranges_intersect_p and
1272 range_includes_zero_p. The semantics of VR_RANGE and
1273 VR_ANTI_RANGE should be encoded here, but that also means
1274 adapting the users of these functions to the new semantics.
1276 Benchmark compile/20001226-1.c compilation time after changing this
1280 value_inside_range (tree val, value_range_t * vr)
1284 cmp1 = operand_less_p (val, vr->min);
1290 cmp2 = operand_less_p (vr->max, val);
1298 /* Return true if value ranges VR0 and VR1 have a non-empty
1301 Benchmark compile/20001226-1.c compilation time after changing this
1306 value_ranges_intersect_p (value_range_t *vr0, value_range_t *vr1)
1308 /* The value ranges do not intersect if the maximum of the first range is
1309 less than the minimum of the second range or vice versa.
1310 When those relations are unknown, we can't do any better. */
1311 if (operand_less_p (vr0->max, vr1->min) != 0)
1313 if (operand_less_p (vr1->max, vr0->min) != 0)
1319 /* Return true if VR includes the value zero, false otherwise. FIXME,
1320 currently this will return false for an anti-range like ~[-4, 3].
1321 This will be wrong when the semantics of value_inside_range are
1322 modified (currently the users of this function expect these
1326 range_includes_zero_p (value_range_t *vr)
1330 gcc_assert (vr->type != VR_UNDEFINED
1331 && vr->type != VR_VARYING
1332 && !symbolic_range_p (vr));
1334 zero = build_int_cst (TREE_TYPE (vr->min), 0);
1335 return (value_inside_range (zero, vr) == 1);
1338 /* Return true if T, an SSA_NAME, is known to be nonnegative. Return
1339 false otherwise or if no value range information is available. */
1342 ssa_name_nonnegative_p (const_tree t)
1344 value_range_t *vr = get_value_range (t);
1349 /* Testing for VR_ANTI_RANGE is not useful here as any anti-range
1350 which would return a useful value should be encoded as a VR_RANGE. */
1351 if (vr->type == VR_RANGE)
1353 int result = compare_values (vr->min, integer_zero_node);
1355 return (result == 0 || result == 1);
1360 /* If OP has a value range with a single constant value return that,
1361 otherwise return NULL_TREE. This returns OP itself if OP is a
1365 op_with_constant_singleton_value_range (tree op)
1369 if (is_gimple_min_invariant (op))
1372 if (TREE_CODE (op) != SSA_NAME)
1375 vr = get_value_range (op);
1376 if (vr->type == VR_RANGE
1377 && operand_equal_p (vr->min, vr->max, 0)
1378 && is_gimple_min_invariant (vr->min))
1385 /* Extract value range information from an ASSERT_EXPR EXPR and store
1389 extract_range_from_assert (value_range_t *vr_p, tree expr)
1391 tree var, cond, limit, min, max, type;
1392 value_range_t *var_vr, *limit_vr;
1393 enum tree_code cond_code;
1395 var = ASSERT_EXPR_VAR (expr);
1396 cond = ASSERT_EXPR_COND (expr);
1398 gcc_assert (COMPARISON_CLASS_P (cond));
1400 /* Find VAR in the ASSERT_EXPR conditional. */
1401 if (var == TREE_OPERAND (cond, 0)
1402 || TREE_CODE (TREE_OPERAND (cond, 0)) == PLUS_EXPR
1403 || TREE_CODE (TREE_OPERAND (cond, 0)) == NOP_EXPR)
1405 /* If the predicate is of the form VAR COMP LIMIT, then we just
1406 take LIMIT from the RHS and use the same comparison code. */
1407 cond_code = TREE_CODE (cond);
1408 limit = TREE_OPERAND (cond, 1);
1409 cond = TREE_OPERAND (cond, 0);
1413 /* If the predicate is of the form LIMIT COMP VAR, then we need
1414 to flip around the comparison code to create the proper range
1416 cond_code = swap_tree_comparison (TREE_CODE (cond));
1417 limit = TREE_OPERAND (cond, 0);
1418 cond = TREE_OPERAND (cond, 1);
1421 limit = avoid_overflow_infinity (limit);
1423 type = TREE_TYPE (limit);
1424 gcc_assert (limit != var);
1426 /* For pointer arithmetic, we only keep track of pointer equality
1428 if (POINTER_TYPE_P (type) && cond_code != NE_EXPR && cond_code != EQ_EXPR)
1430 set_value_range_to_varying (vr_p);
1434 /* If LIMIT is another SSA name and LIMIT has a range of its own,
1435 try to use LIMIT's range to avoid creating symbolic ranges
1437 limit_vr = (TREE_CODE (limit) == SSA_NAME) ? get_value_range (limit) : NULL;
1439 /* LIMIT's range is only interesting if it has any useful information. */
1441 && (limit_vr->type == VR_UNDEFINED
1442 || limit_vr->type == VR_VARYING
1443 || symbolic_range_p (limit_vr)))
1446 /* Initially, the new range has the same set of equivalences of
1447 VAR's range. This will be revised before returning the final
1448 value. Since assertions may be chained via mutually exclusive
1449 predicates, we will need to trim the set of equivalences before
1451 gcc_assert (vr_p->equiv == NULL);
1452 add_equivalence (&vr_p->equiv, var);
1454 /* Extract a new range based on the asserted comparison for VAR and
1455 LIMIT's value range. Notice that if LIMIT has an anti-range, we
1456 will only use it for equality comparisons (EQ_EXPR). For any
1457 other kind of assertion, we cannot derive a range from LIMIT's
1458 anti-range that can be used to describe the new range. For
1459 instance, ASSERT_EXPR <x_2, x_2 <= b_4>. If b_4 is ~[2, 10],
1460 then b_4 takes on the ranges [-INF, 1] and [11, +INF]. There is
1461 no single range for x_2 that could describe LE_EXPR, so we might
1462 as well build the range [b_4, +INF] for it.
1463 One special case we handle is extracting a range from a
1464 range test encoded as (unsigned)var + CST <= limit. */
1465 if (TREE_CODE (cond) == NOP_EXPR
1466 || TREE_CODE (cond) == PLUS_EXPR)
1468 if (TREE_CODE (cond) == PLUS_EXPR)
1470 min = fold_build1 (NEGATE_EXPR, TREE_TYPE (TREE_OPERAND (cond, 1)),
1471 TREE_OPERAND (cond, 1));
1472 max = int_const_binop (PLUS_EXPR, limit, min, 0);
1473 cond = TREE_OPERAND (cond, 0);
1477 min = build_int_cst (TREE_TYPE (var), 0);
1481 /* Make sure to not set TREE_OVERFLOW on the final type
1482 conversion. We are willingly interpreting large positive
1483 unsigned values as negative singed values here. */
1484 min = force_fit_type_double (TREE_TYPE (var), TREE_INT_CST_LOW (min),
1485 TREE_INT_CST_HIGH (min), 0, false);
1486 max = force_fit_type_double (TREE_TYPE (var), TREE_INT_CST_LOW (max),
1487 TREE_INT_CST_HIGH (max), 0, false);
1489 /* We can transform a max, min range to an anti-range or
1490 vice-versa. Use set_and_canonicalize_value_range which does
1492 if (cond_code == LE_EXPR)
1493 set_and_canonicalize_value_range (vr_p, VR_RANGE,
1494 min, max, vr_p->equiv);
1495 else if (cond_code == GT_EXPR)
1496 set_and_canonicalize_value_range (vr_p, VR_ANTI_RANGE,
1497 min, max, vr_p->equiv);
1501 else if (cond_code == EQ_EXPR)
1503 enum value_range_type range_type;
1507 range_type = limit_vr->type;
1508 min = limit_vr->min;
1509 max = limit_vr->max;
1513 range_type = VR_RANGE;
1518 set_value_range (vr_p, range_type, min, max, vr_p->equiv);
1520 /* When asserting the equality VAR == LIMIT and LIMIT is another
1521 SSA name, the new range will also inherit the equivalence set
1523 if (TREE_CODE (limit) == SSA_NAME)
1524 add_equivalence (&vr_p->equiv, limit);
1526 else if (cond_code == NE_EXPR)
1528 /* As described above, when LIMIT's range is an anti-range and
1529 this assertion is an inequality (NE_EXPR), then we cannot
1530 derive anything from the anti-range. For instance, if
1531 LIMIT's range was ~[0, 0], the assertion 'VAR != LIMIT' does
1532 not imply that VAR's range is [0, 0]. So, in the case of
1533 anti-ranges, we just assert the inequality using LIMIT and
1536 If LIMIT_VR is a range, we can only use it to build a new
1537 anti-range if LIMIT_VR is a single-valued range. For
1538 instance, if LIMIT_VR is [0, 1], the predicate
1539 VAR != [0, 1] does not mean that VAR's range is ~[0, 1].
1540 Rather, it means that for value 0 VAR should be ~[0, 0]
1541 and for value 1, VAR should be ~[1, 1]. We cannot
1542 represent these ranges.
1544 The only situation in which we can build a valid
1545 anti-range is when LIMIT_VR is a single-valued range
1546 (i.e., LIMIT_VR->MIN == LIMIT_VR->MAX). In that case,
1547 build the anti-range ~[LIMIT_VR->MIN, LIMIT_VR->MAX]. */
1549 && limit_vr->type == VR_RANGE
1550 && compare_values (limit_vr->min, limit_vr->max) == 0)
1552 min = limit_vr->min;
1553 max = limit_vr->max;
1557 /* In any other case, we cannot use LIMIT's range to build a
1558 valid anti-range. */
1562 /* If MIN and MAX cover the whole range for their type, then
1563 just use the original LIMIT. */
1564 if (INTEGRAL_TYPE_P (type)
1565 && vrp_val_is_min (min)
1566 && vrp_val_is_max (max))
1569 set_value_range (vr_p, VR_ANTI_RANGE, min, max, vr_p->equiv);
1571 else if (cond_code == LE_EXPR || cond_code == LT_EXPR)
1573 min = TYPE_MIN_VALUE (type);
1575 if (limit_vr == NULL || limit_vr->type == VR_ANTI_RANGE)
1579 /* If LIMIT_VR is of the form [N1, N2], we need to build the
1580 range [MIN, N2] for LE_EXPR and [MIN, N2 - 1] for
1582 max = limit_vr->max;
1585 /* If the maximum value forces us to be out of bounds, simply punt.
1586 It would be pointless to try and do anything more since this
1587 all should be optimized away above us. */
1588 if ((cond_code == LT_EXPR
1589 && compare_values (max, min) == 0)
1590 || (CONSTANT_CLASS_P (max) && TREE_OVERFLOW (max)))
1591 set_value_range_to_varying (vr_p);
1594 /* For LT_EXPR, we create the range [MIN, MAX - 1]. */
1595 if (cond_code == LT_EXPR)
1597 tree one = build_int_cst (type, 1);
1598 max = fold_build2 (MINUS_EXPR, type, max, one);
1600 TREE_NO_WARNING (max) = 1;
1603 set_value_range (vr_p, VR_RANGE, min, max, vr_p->equiv);
1606 else if (cond_code == GE_EXPR || cond_code == GT_EXPR)
1608 max = TYPE_MAX_VALUE (type);
1610 if (limit_vr == NULL || limit_vr->type == VR_ANTI_RANGE)
1614 /* If LIMIT_VR is of the form [N1, N2], we need to build the
1615 range [N1, MAX] for GE_EXPR and [N1 + 1, MAX] for
1617 min = limit_vr->min;
1620 /* If the minimum value forces us to be out of bounds, simply punt.
1621 It would be pointless to try and do anything more since this
1622 all should be optimized away above us. */
1623 if ((cond_code == GT_EXPR
1624 && compare_values (min, max) == 0)
1625 || (CONSTANT_CLASS_P (min) && TREE_OVERFLOW (min)))
1626 set_value_range_to_varying (vr_p);
1629 /* For GT_EXPR, we create the range [MIN + 1, MAX]. */
1630 if (cond_code == GT_EXPR)
1632 tree one = build_int_cst (type, 1);
1633 min = fold_build2 (PLUS_EXPR, type, min, one);
1635 TREE_NO_WARNING (min) = 1;
1638 set_value_range (vr_p, VR_RANGE, min, max, vr_p->equiv);
1644 /* If VAR already had a known range, it may happen that the new
1645 range we have computed and VAR's range are not compatible. For
1649 p_6 = ASSERT_EXPR <p_5, p_5 == NULL>;
1651 p_8 = ASSERT_EXPR <p_6, p_6 != NULL>;
1653 While the above comes from a faulty program, it will cause an ICE
1654 later because p_8 and p_6 will have incompatible ranges and at
1655 the same time will be considered equivalent. A similar situation
1659 i_6 = ASSERT_EXPR <i_5, i_5 > 10>;
1661 i_7 = ASSERT_EXPR <i_6, i_6 < 5>;
1663 Again i_6 and i_7 will have incompatible ranges. It would be
1664 pointless to try and do anything with i_7's range because
1665 anything dominated by 'if (i_5 < 5)' will be optimized away.
1666 Note, due to the wa in which simulation proceeds, the statement
1667 i_7 = ASSERT_EXPR <...> we would never be visited because the
1668 conditional 'if (i_5 < 5)' always evaluates to false. However,
1669 this extra check does not hurt and may protect against future
1670 changes to VRP that may get into a situation similar to the
1671 NULL pointer dereference example.
1673 Note that these compatibility tests are only needed when dealing
1674 with ranges or a mix of range and anti-range. If VAR_VR and VR_P
1675 are both anti-ranges, they will always be compatible, because two
1676 anti-ranges will always have a non-empty intersection. */
1678 var_vr = get_value_range (var);
1680 /* We may need to make adjustments when VR_P and VAR_VR are numeric
1681 ranges or anti-ranges. */
1682 if (vr_p->type == VR_VARYING
1683 || vr_p->type == VR_UNDEFINED
1684 || var_vr->type == VR_VARYING
1685 || var_vr->type == VR_UNDEFINED
1686 || symbolic_range_p (vr_p)
1687 || symbolic_range_p (var_vr))
1690 if (var_vr->type == VR_RANGE && vr_p->type == VR_RANGE)
1692 /* If the two ranges have a non-empty intersection, we can
1693 refine the resulting range. Since the assert expression
1694 creates an equivalency and at the same time it asserts a
1695 predicate, we can take the intersection of the two ranges to
1696 get better precision. */
1697 if (value_ranges_intersect_p (var_vr, vr_p))
1699 /* Use the larger of the two minimums. */
1700 if (compare_values (vr_p->min, var_vr->min) == -1)
1705 /* Use the smaller of the two maximums. */
1706 if (compare_values (vr_p->max, var_vr->max) == 1)
1711 set_value_range (vr_p, vr_p->type, min, max, vr_p->equiv);
1715 /* The two ranges do not intersect, set the new range to
1716 VARYING, because we will not be able to do anything
1717 meaningful with it. */
1718 set_value_range_to_varying (vr_p);
1721 else if ((var_vr->type == VR_RANGE && vr_p->type == VR_ANTI_RANGE)
1722 || (var_vr->type == VR_ANTI_RANGE && vr_p->type == VR_RANGE))
1724 /* A range and an anti-range will cancel each other only if
1725 their ends are the same. For instance, in the example above,
1726 p_8's range ~[0, 0] and p_6's range [0, 0] are incompatible,
1727 so VR_P should be set to VR_VARYING. */
1728 if (compare_values (var_vr->min, vr_p->min) == 0
1729 && compare_values (var_vr->max, vr_p->max) == 0)
1730 set_value_range_to_varying (vr_p);
1733 tree min, max, anti_min, anti_max, real_min, real_max;
1736 /* We want to compute the logical AND of the two ranges;
1737 there are three cases to consider.
1740 1. The VR_ANTI_RANGE range is completely within the
1741 VR_RANGE and the endpoints of the ranges are
1742 different. In that case the resulting range
1743 should be whichever range is more precise.
1744 Typically that will be the VR_RANGE.
1746 2. The VR_ANTI_RANGE is completely disjoint from
1747 the VR_RANGE. In this case the resulting range
1748 should be the VR_RANGE.
1750 3. There is some overlap between the VR_ANTI_RANGE
1753 3a. If the high limit of the VR_ANTI_RANGE resides
1754 within the VR_RANGE, then the result is a new
1755 VR_RANGE starting at the high limit of the
1756 VR_ANTI_RANGE + 1 and extending to the
1757 high limit of the original VR_RANGE.
1759 3b. If the low limit of the VR_ANTI_RANGE resides
1760 within the VR_RANGE, then the result is a new
1761 VR_RANGE starting at the low limit of the original
1762 VR_RANGE and extending to the low limit of the
1763 VR_ANTI_RANGE - 1. */
1764 if (vr_p->type == VR_ANTI_RANGE)
1766 anti_min = vr_p->min;
1767 anti_max = vr_p->max;
1768 real_min = var_vr->min;
1769 real_max = var_vr->max;
1773 anti_min = var_vr->min;
1774 anti_max = var_vr->max;
1775 real_min = vr_p->min;
1776 real_max = vr_p->max;
1780 /* Case 1, VR_ANTI_RANGE completely within VR_RANGE,
1781 not including any endpoints. */
1782 if (compare_values (anti_max, real_max) == -1
1783 && compare_values (anti_min, real_min) == 1)
1785 /* If the range is covering the whole valid range of
1786 the type keep the anti-range. */
1787 if (!vrp_val_is_min (real_min)
1788 || !vrp_val_is_max (real_max))
1789 set_value_range (vr_p, VR_RANGE, real_min,
1790 real_max, vr_p->equiv);
1792 /* Case 2, VR_ANTI_RANGE completely disjoint from
1794 else if (compare_values (anti_min, real_max) == 1
1795 || compare_values (anti_max, real_min) == -1)
1797 set_value_range (vr_p, VR_RANGE, real_min,
1798 real_max, vr_p->equiv);
1800 /* Case 3a, the anti-range extends into the low
1801 part of the real range. Thus creating a new
1802 low for the real range. */
1803 else if (((cmp = compare_values (anti_max, real_min)) == 1
1805 && compare_values (anti_max, real_max) == -1)
1807 gcc_assert (!is_positive_overflow_infinity (anti_max));
1808 if (needs_overflow_infinity (TREE_TYPE (anti_max))
1809 && vrp_val_is_max (anti_max))
1811 if (!supports_overflow_infinity (TREE_TYPE (var_vr->min)))
1813 set_value_range_to_varying (vr_p);
1816 min = positive_overflow_infinity (TREE_TYPE (var_vr->min));
1818 else if (!POINTER_TYPE_P (TREE_TYPE (var_vr->min)))
1819 min = fold_build2 (PLUS_EXPR, TREE_TYPE (var_vr->min),
1821 build_int_cst (TREE_TYPE (var_vr->min), 1));
1823 min = fold_build2 (POINTER_PLUS_EXPR, TREE_TYPE (var_vr->min),
1824 anti_max, size_int (1));
1826 set_value_range (vr_p, VR_RANGE, min, max, vr_p->equiv);
1828 /* Case 3b, the anti-range extends into the high
1829 part of the real range. Thus creating a new
1830 higher for the real range. */
1831 else if (compare_values (anti_min, real_min) == 1
1832 && ((cmp = compare_values (anti_min, real_max)) == -1
1835 gcc_assert (!is_negative_overflow_infinity (anti_min));
1836 if (needs_overflow_infinity (TREE_TYPE (anti_min))
1837 && vrp_val_is_min (anti_min))
1839 if (!supports_overflow_infinity (TREE_TYPE (var_vr->min)))
1841 set_value_range_to_varying (vr_p);
1844 max = negative_overflow_infinity (TREE_TYPE (var_vr->min));
1846 else if (!POINTER_TYPE_P (TREE_TYPE (var_vr->min)))
1847 max = fold_build2 (MINUS_EXPR, TREE_TYPE (var_vr->min),
1849 build_int_cst (TREE_TYPE (var_vr->min), 1));
1851 max = fold_build2 (POINTER_PLUS_EXPR, TREE_TYPE (var_vr->min),
1855 set_value_range (vr_p, VR_RANGE, min, max, vr_p->equiv);
1862 /* Extract range information from SSA name VAR and store it in VR. If
1863 VAR has an interesting range, use it. Otherwise, create the
1864 range [VAR, VAR] and return it. This is useful in situations where
1865 we may have conditionals testing values of VARYING names. For
1872 Even if y_5 is deemed VARYING, we can determine that x_3 > y_5 is
1876 extract_range_from_ssa_name (value_range_t *vr, tree var)
1878 value_range_t *var_vr = get_value_range (var);
1880 if (var_vr->type != VR_UNDEFINED && var_vr->type != VR_VARYING)
1881 copy_value_range (vr, var_vr);
1883 set_value_range (vr, VR_RANGE, var, var, NULL);
1885 add_equivalence (&vr->equiv, var);
1889 /* Wrapper around int_const_binop. If the operation overflows and we
1890 are not using wrapping arithmetic, then adjust the result to be
1891 -INF or +INF depending on CODE, VAL1 and VAL2. This can return
1892 NULL_TREE if we need to use an overflow infinity representation but
1893 the type does not support it. */
1896 vrp_int_const_binop (enum tree_code code, tree val1, tree val2)
1900 res = int_const_binop (code, val1, val2, 0);
1902 /* If we are using unsigned arithmetic, operate symbolically
1903 on -INF and +INF as int_const_binop only handles signed overflow. */
1904 if (TYPE_UNSIGNED (TREE_TYPE (val1)))
1906 int checkz = compare_values (res, val1);
1907 bool overflow = false;
1909 /* Ensure that res = val1 [+*] val2 >= val1
1910 or that res = val1 - val2 <= val1. */
1911 if ((code == PLUS_EXPR
1912 && !(checkz == 1 || checkz == 0))
1913 || (code == MINUS_EXPR
1914 && !(checkz == 0 || checkz == -1)))
1918 /* Checking for multiplication overflow is done by dividing the
1919 output of the multiplication by the first input of the
1920 multiplication. If the result of that division operation is
1921 not equal to the second input of the multiplication, then the
1922 multiplication overflowed. */
1923 else if (code == MULT_EXPR && !integer_zerop (val1))
1925 tree tmp = int_const_binop (TRUNC_DIV_EXPR,
1928 int check = compare_values (tmp, val2);
1936 res = copy_node (res);
1937 TREE_OVERFLOW (res) = 1;
1941 else if (TYPE_OVERFLOW_WRAPS (TREE_TYPE (val1)))
1942 /* If the singed operation wraps then int_const_binop has done
1943 everything we want. */
1945 else if ((TREE_OVERFLOW (res)
1946 && !TREE_OVERFLOW (val1)
1947 && !TREE_OVERFLOW (val2))
1948 || is_overflow_infinity (val1)
1949 || is_overflow_infinity (val2))
1951 /* If the operation overflowed but neither VAL1 nor VAL2 are
1952 overflown, return -INF or +INF depending on the operation
1953 and the combination of signs of the operands. */
1954 int sgn1 = tree_int_cst_sgn (val1);
1955 int sgn2 = tree_int_cst_sgn (val2);
1957 if (needs_overflow_infinity (TREE_TYPE (res))
1958 && !supports_overflow_infinity (TREE_TYPE (res)))
1961 /* We have to punt on adding infinities of different signs,
1962 since we can't tell what the sign of the result should be.
1963 Likewise for subtracting infinities of the same sign. */
1964 if (((code == PLUS_EXPR && sgn1 != sgn2)
1965 || (code == MINUS_EXPR && sgn1 == sgn2))
1966 && is_overflow_infinity (val1)
1967 && is_overflow_infinity (val2))
1970 /* Don't try to handle division or shifting of infinities. */
1971 if ((code == TRUNC_DIV_EXPR
1972 || code == FLOOR_DIV_EXPR
1973 || code == CEIL_DIV_EXPR
1974 || code == EXACT_DIV_EXPR
1975 || code == ROUND_DIV_EXPR
1976 || code == RSHIFT_EXPR)
1977 && (is_overflow_infinity (val1)
1978 || is_overflow_infinity (val2)))
1981 /* Notice that we only need to handle the restricted set of
1982 operations handled by extract_range_from_binary_expr.
1983 Among them, only multiplication, addition and subtraction
1984 can yield overflow without overflown operands because we
1985 are working with integral types only... except in the
1986 case VAL1 = -INF and VAL2 = -1 which overflows to +INF
1987 for division too. */
1989 /* For multiplication, the sign of the overflow is given
1990 by the comparison of the signs of the operands. */
1991 if ((code == MULT_EXPR && sgn1 == sgn2)
1992 /* For addition, the operands must be of the same sign
1993 to yield an overflow. Its sign is therefore that
1994 of one of the operands, for example the first. For
1995 infinite operands X + -INF is negative, not positive. */
1996 || (code == PLUS_EXPR
1998 ? !is_negative_overflow_infinity (val2)
1999 : is_positive_overflow_infinity (val2)))
2000 /* For subtraction, non-infinite operands must be of
2001 different signs to yield an overflow. Its sign is
2002 therefore that of the first operand or the opposite of
2003 that of the second operand. A first operand of 0 counts
2004 as positive here, for the corner case 0 - (-INF), which
2005 overflows, but must yield +INF. For infinite operands 0
2006 - INF is negative, not positive. */
2007 || (code == MINUS_EXPR
2009 ? !is_positive_overflow_infinity (val2)
2010 : is_negative_overflow_infinity (val2)))
2011 /* We only get in here with positive shift count, so the
2012 overflow direction is the same as the sign of val1.
2013 Actually rshift does not overflow at all, but we only
2014 handle the case of shifting overflowed -INF and +INF. */
2015 || (code == RSHIFT_EXPR
2017 /* For division, the only case is -INF / -1 = +INF. */
2018 || code == TRUNC_DIV_EXPR
2019 || code == FLOOR_DIV_EXPR
2020 || code == CEIL_DIV_EXPR
2021 || code == EXACT_DIV_EXPR
2022 || code == ROUND_DIV_EXPR)
2023 return (needs_overflow_infinity (TREE_TYPE (res))
2024 ? positive_overflow_infinity (TREE_TYPE (res))
2025 : TYPE_MAX_VALUE (TREE_TYPE (res)));
2027 return (needs_overflow_infinity (TREE_TYPE (res))
2028 ? negative_overflow_infinity (TREE_TYPE (res))
2029 : TYPE_MIN_VALUE (TREE_TYPE (res)));
2036 /* Extract range information from a binary expression EXPR based on
2037 the ranges of each of its operands and the expression code. */
2040 extract_range_from_binary_expr (value_range_t *vr,
2041 enum tree_code code,
2042 tree expr_type, tree op0, tree op1)
2044 enum value_range_type type;
2047 value_range_t vr0 = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
2048 value_range_t vr1 = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
2050 /* Not all binary expressions can be applied to ranges in a
2051 meaningful way. Handle only arithmetic operations. */
2052 if (code != PLUS_EXPR
2053 && code != MINUS_EXPR
2054 && code != POINTER_PLUS_EXPR
2055 && code != MULT_EXPR
2056 && code != TRUNC_DIV_EXPR
2057 && code != FLOOR_DIV_EXPR
2058 && code != CEIL_DIV_EXPR
2059 && code != EXACT_DIV_EXPR
2060 && code != ROUND_DIV_EXPR
2061 && code != RSHIFT_EXPR
2064 && code != BIT_AND_EXPR
2065 && code != BIT_IOR_EXPR
2066 && code != TRUTH_AND_EXPR
2067 && code != TRUTH_OR_EXPR)
2069 /* We can still do constant propagation here. */
2070 tree const_op0 = op_with_constant_singleton_value_range (op0);
2071 tree const_op1 = op_with_constant_singleton_value_range (op1);
2072 if (const_op0 || const_op1)
2074 tree tem = fold_binary (code, expr_type,
2075 const_op0 ? const_op0 : op0,
2076 const_op1 ? const_op1 : op1);
2078 && is_gimple_min_invariant (tem)
2079 && !is_overflow_infinity (tem))
2081 set_value_range (vr, VR_RANGE, tem, tem, NULL);
2085 set_value_range_to_varying (vr);
2089 /* Get value ranges for each operand. For constant operands, create
2090 a new value range with the operand to simplify processing. */
2091 if (TREE_CODE (op0) == SSA_NAME)
2092 vr0 = *(get_value_range (op0));
2093 else if (is_gimple_min_invariant (op0))
2094 set_value_range_to_value (&vr0, op0, NULL);
2096 set_value_range_to_varying (&vr0);
2098 if (TREE_CODE (op1) == SSA_NAME)
2099 vr1 = *(get_value_range (op1));
2100 else if (is_gimple_min_invariant (op1))
2101 set_value_range_to_value (&vr1, op1, NULL);
2103 set_value_range_to_varying (&vr1);
2105 /* If either range is UNDEFINED, so is the result. */
2106 if (vr0.type == VR_UNDEFINED || vr1.type == VR_UNDEFINED)
2108 set_value_range_to_undefined (vr);
2112 /* The type of the resulting value range defaults to VR0.TYPE. */
2115 /* Refuse to operate on VARYING ranges, ranges of different kinds
2116 and symbolic ranges. As an exception, we allow BIT_AND_EXPR
2117 because we may be able to derive a useful range even if one of
2118 the operands is VR_VARYING or symbolic range. Similarly for
2119 divisions. TODO, we may be able to derive anti-ranges in
2121 if (code != BIT_AND_EXPR
2122 && code != TRUTH_AND_EXPR
2123 && code != TRUTH_OR_EXPR
2124 && code != TRUNC_DIV_EXPR
2125 && code != FLOOR_DIV_EXPR
2126 && code != CEIL_DIV_EXPR
2127 && code != EXACT_DIV_EXPR
2128 && code != ROUND_DIV_EXPR
2129 && (vr0.type == VR_VARYING
2130 || vr1.type == VR_VARYING
2131 || vr0.type != vr1.type
2132 || symbolic_range_p (&vr0)
2133 || symbolic_range_p (&vr1)))
2135 set_value_range_to_varying (vr);
2139 /* Now evaluate the expression to determine the new range. */
2140 if (POINTER_TYPE_P (expr_type)
2141 || POINTER_TYPE_P (TREE_TYPE (op0))
2142 || POINTER_TYPE_P (TREE_TYPE (op1)))
2144 if (code == MIN_EXPR || code == MAX_EXPR)
2146 /* For MIN/MAX expressions with pointers, we only care about
2147 nullness, if both are non null, then the result is nonnull.
2148 If both are null, then the result is null. Otherwise they
2150 if (range_is_nonnull (&vr0) && range_is_nonnull (&vr1))
2151 set_value_range_to_nonnull (vr, expr_type);
2152 else if (range_is_null (&vr0) && range_is_null (&vr1))
2153 set_value_range_to_null (vr, expr_type);
2155 set_value_range_to_varying (vr);
2159 gcc_assert (code == POINTER_PLUS_EXPR);
2160 /* For pointer types, we are really only interested in asserting
2161 whether the expression evaluates to non-NULL. */
2162 if (range_is_nonnull (&vr0) || range_is_nonnull (&vr1))
2163 set_value_range_to_nonnull (vr, expr_type);
2164 else if (range_is_null (&vr0) && range_is_null (&vr1))
2165 set_value_range_to_null (vr, expr_type);
2167 set_value_range_to_varying (vr);
2172 /* For integer ranges, apply the operation to each end of the
2173 range and see what we end up with. */
2174 if (code == TRUTH_AND_EXPR
2175 || code == TRUTH_OR_EXPR)
2177 /* If one of the operands is zero, we know that the whole
2178 expression evaluates zero. */
2179 if (code == TRUTH_AND_EXPR
2180 && ((vr0.type == VR_RANGE
2181 && integer_zerop (vr0.min)
2182 && integer_zerop (vr0.max))
2183 || (vr1.type == VR_RANGE
2184 && integer_zerop (vr1.min)
2185 && integer_zerop (vr1.max))))
2188 min = max = build_int_cst (expr_type, 0);
2190 /* If one of the operands is one, we know that the whole
2191 expression evaluates one. */
2192 else if (code == TRUTH_OR_EXPR
2193 && ((vr0.type == VR_RANGE
2194 && integer_onep (vr0.min)
2195 && integer_onep (vr0.max))
2196 || (vr1.type == VR_RANGE
2197 && integer_onep (vr1.min)
2198 && integer_onep (vr1.max))))
2201 min = max = build_int_cst (expr_type, 1);
2203 else if (vr0.type != VR_VARYING
2204 && vr1.type != VR_VARYING
2205 && vr0.type == vr1.type
2206 && !symbolic_range_p (&vr0)
2207 && !overflow_infinity_range_p (&vr0)
2208 && !symbolic_range_p (&vr1)
2209 && !overflow_infinity_range_p (&vr1))
2211 /* Boolean expressions cannot be folded with int_const_binop. */
2212 min = fold_binary (code, expr_type, vr0.min, vr1.min);
2213 max = fold_binary (code, expr_type, vr0.max, vr1.max);
2217 /* The result of a TRUTH_*_EXPR is always true or false. */
2218 set_value_range_to_truthvalue (vr, expr_type);
2222 else if (code == PLUS_EXPR
2224 || code == MAX_EXPR)
2226 /* If we have a PLUS_EXPR with two VR_ANTI_RANGEs, drop to
2227 VR_VARYING. It would take more effort to compute a precise
2228 range for such a case. For example, if we have op0 == 1 and
2229 op1 == -1 with their ranges both being ~[0,0], we would have
2230 op0 + op1 == 0, so we cannot claim that the sum is in ~[0,0].
2231 Note that we are guaranteed to have vr0.type == vr1.type at
2233 if (code == PLUS_EXPR && vr0.type == VR_ANTI_RANGE)
2235 set_value_range_to_varying (vr);
2239 /* For operations that make the resulting range directly
2240 proportional to the original ranges, apply the operation to
2241 the same end of each range. */
2242 min = vrp_int_const_binop (code, vr0.min, vr1.min);
2243 max = vrp_int_const_binop (code, vr0.max, vr1.max);
2245 /* If both additions overflowed the range kind is still correct.
2246 This happens regularly with subtracting something in unsigned
2248 ??? See PR30318 for all the cases we do not handle. */
2249 if (code == PLUS_EXPR
2250 && (TREE_OVERFLOW (min) && !is_overflow_infinity (min))
2251 && (TREE_OVERFLOW (max) && !is_overflow_infinity (max)))
2253 min = build_int_cst_wide (TREE_TYPE (min),
2254 TREE_INT_CST_LOW (min),
2255 TREE_INT_CST_HIGH (min));
2256 max = build_int_cst_wide (TREE_TYPE (max),
2257 TREE_INT_CST_LOW (max),
2258 TREE_INT_CST_HIGH (max));
2261 else if (code == MULT_EXPR
2262 || code == TRUNC_DIV_EXPR
2263 || code == FLOOR_DIV_EXPR
2264 || code == CEIL_DIV_EXPR
2265 || code == EXACT_DIV_EXPR
2266 || code == ROUND_DIV_EXPR
2267 || code == RSHIFT_EXPR)
2273 /* If we have an unsigned MULT_EXPR with two VR_ANTI_RANGEs,
2274 drop to VR_VARYING. It would take more effort to compute a
2275 precise range for such a case. For example, if we have
2276 op0 == 65536 and op1 == 65536 with their ranges both being
2277 ~[0,0] on a 32-bit machine, we would have op0 * op1 == 0, so
2278 we cannot claim that the product is in ~[0,0]. Note that we
2279 are guaranteed to have vr0.type == vr1.type at this
2281 if (code == MULT_EXPR
2282 && vr0.type == VR_ANTI_RANGE
2283 && !TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (op0)))
2285 set_value_range_to_varying (vr);
2289 /* If we have a RSHIFT_EXPR with any shift values outside [0..prec-1],
2290 then drop to VR_VARYING. Outside of this range we get undefined
2291 behavior from the shift operation. We cannot even trust
2292 SHIFT_COUNT_TRUNCATED at this stage, because that applies to rtl
2293 shifts, and the operation at the tree level may be widened. */
2294 if (code == RSHIFT_EXPR)
2296 if (vr1.type == VR_ANTI_RANGE
2297 || !vrp_expr_computes_nonnegative (op1, &sop)
2299 (build_int_cst (TREE_TYPE (vr1.max),
2300 TYPE_PRECISION (expr_type) - 1),
2303 set_value_range_to_varying (vr);
2308 else if ((code == TRUNC_DIV_EXPR
2309 || code == FLOOR_DIV_EXPR
2310 || code == CEIL_DIV_EXPR
2311 || code == EXACT_DIV_EXPR
2312 || code == ROUND_DIV_EXPR)
2313 && (vr0.type != VR_RANGE || symbolic_range_p (&vr0)))
2315 /* For division, if op1 has VR_RANGE but op0 does not, something
2316 can be deduced just from that range. Say [min, max] / [4, max]
2317 gives [min / 4, max / 4] range. */
2318 if (vr1.type == VR_RANGE
2319 && !symbolic_range_p (&vr1)
2320 && !range_includes_zero_p (&vr1))
2322 vr0.type = type = VR_RANGE;
2323 vr0.min = vrp_val_min (TREE_TYPE (op0));
2324 vr0.max = vrp_val_max (TREE_TYPE (op1));
2328 set_value_range_to_varying (vr);
2333 /* For divisions, if op0 is VR_RANGE, we can deduce a range
2334 even if op1 is VR_VARYING, VR_ANTI_RANGE, symbolic or can
2336 if ((code == TRUNC_DIV_EXPR
2337 || code == FLOOR_DIV_EXPR
2338 || code == CEIL_DIV_EXPR
2339 || code == EXACT_DIV_EXPR
2340 || code == ROUND_DIV_EXPR)
2341 && vr0.type == VR_RANGE
2342 && (vr1.type != VR_RANGE
2343 || symbolic_range_p (&vr1)
2344 || range_includes_zero_p (&vr1)))
2346 tree zero = build_int_cst (TREE_TYPE (vr0.min), 0);
2352 if (vrp_expr_computes_nonnegative (op1, &sop) && !sop)
2354 /* For unsigned division or when divisor is known
2355 to be non-negative, the range has to cover
2356 all numbers from 0 to max for positive max
2357 and all numbers from min to 0 for negative min. */
2358 cmp = compare_values (vr0.max, zero);
2361 else if (cmp == 0 || cmp == 1)
2365 cmp = compare_values (vr0.min, zero);
2368 else if (cmp == 0 || cmp == -1)
2375 /* Otherwise the range is -max .. max or min .. -min
2376 depending on which bound is bigger in absolute value,
2377 as the division can change the sign. */
2378 abs_extent_range (vr, vr0.min, vr0.max);
2381 if (type == VR_VARYING)
2383 set_value_range_to_varying (vr);
2388 /* Multiplications and divisions are a bit tricky to handle,
2389 depending on the mix of signs we have in the two ranges, we
2390 need to operate on different values to get the minimum and
2391 maximum values for the new range. One approach is to figure
2392 out all the variations of range combinations and do the
2395 However, this involves several calls to compare_values and it
2396 is pretty convoluted. It's simpler to do the 4 operations
2397 (MIN0 OP MIN1, MIN0 OP MAX1, MAX0 OP MIN1 and MAX0 OP MAX0 OP
2398 MAX1) and then figure the smallest and largest values to form
2402 gcc_assert ((vr0.type == VR_RANGE
2403 || (code == MULT_EXPR && vr0.type == VR_ANTI_RANGE))
2404 && vr0.type == vr1.type);
2406 /* Compute the 4 cross operations. */
2408 val[0] = vrp_int_const_binop (code, vr0.min, vr1.min);
2409 if (val[0] == NULL_TREE)
2412 if (vr1.max == vr1.min)
2416 val[1] = vrp_int_const_binop (code, vr0.min, vr1.max);
2417 if (val[1] == NULL_TREE)
2421 if (vr0.max == vr0.min)
2425 val[2] = vrp_int_const_binop (code, vr0.max, vr1.min);
2426 if (val[2] == NULL_TREE)
2430 if (vr0.min == vr0.max || vr1.min == vr1.max)
2434 val[3] = vrp_int_const_binop (code, vr0.max, vr1.max);
2435 if (val[3] == NULL_TREE)
2441 set_value_range_to_varying (vr);
2445 /* Set MIN to the minimum of VAL[i] and MAX to the maximum
2449 for (i = 1; i < 4; i++)
2451 if (!is_gimple_min_invariant (min)
2452 || (TREE_OVERFLOW (min) && !is_overflow_infinity (min))
2453 || !is_gimple_min_invariant (max)
2454 || (TREE_OVERFLOW (max) && !is_overflow_infinity (max)))
2459 if (!is_gimple_min_invariant (val[i])
2460 || (TREE_OVERFLOW (val[i])
2461 && !is_overflow_infinity (val[i])))
2463 /* If we found an overflowed value, set MIN and MAX
2464 to it so that we set the resulting range to
2470 if (compare_values (val[i], min) == -1)
2473 if (compare_values (val[i], max) == 1)
2479 else if (code == MINUS_EXPR)
2481 /* If we have a MINUS_EXPR with two VR_ANTI_RANGEs, drop to
2482 VR_VARYING. It would take more effort to compute a precise
2483 range for such a case. For example, if we have op0 == 1 and
2484 op1 == 1 with their ranges both being ~[0,0], we would have
2485 op0 - op1 == 0, so we cannot claim that the difference is in
2486 ~[0,0]. Note that we are guaranteed to have
2487 vr0.type == vr1.type at this point. */
2488 if (vr0.type == VR_ANTI_RANGE)
2490 set_value_range_to_varying (vr);
2494 /* For MINUS_EXPR, apply the operation to the opposite ends of
2496 min = vrp_int_const_binop (code, vr0.min, vr1.max);
2497 max = vrp_int_const_binop (code, vr0.max, vr1.min);
2499 else if (code == BIT_AND_EXPR)
2501 if (vr0.type == VR_RANGE
2502 && vr0.min == vr0.max
2503 && TREE_CODE (vr0.max) == INTEGER_CST
2504 && !TREE_OVERFLOW (vr0.max)
2505 && tree_int_cst_sgn (vr0.max) >= 0)
2507 min = build_int_cst (expr_type, 0);
2510 else if (vr1.type == VR_RANGE
2511 && vr1.min == vr1.max
2512 && TREE_CODE (vr1.max) == INTEGER_CST
2513 && !TREE_OVERFLOW (vr1.max)
2514 && tree_int_cst_sgn (vr1.max) >= 0)
2517 min = build_int_cst (expr_type, 0);
2522 set_value_range_to_varying (vr);
2526 else if (code == BIT_IOR_EXPR)
2528 if (vr0.type == VR_RANGE
2529 && vr1.type == VR_RANGE
2530 && TREE_CODE (vr0.min) == INTEGER_CST
2531 && TREE_CODE (vr1.min) == INTEGER_CST
2532 && TREE_CODE (vr0.max) == INTEGER_CST
2533 && TREE_CODE (vr1.max) == INTEGER_CST
2534 && tree_int_cst_sgn (vr0.min) >= 0
2535 && tree_int_cst_sgn (vr1.min) >= 0)
2537 double_int vr0_max = tree_to_double_int (vr0.max);
2538 double_int vr1_max = tree_to_double_int (vr1.max);
2541 /* Set all bits to the right of the most significant one to 1.
2542 For example, [0, 4] | [4, 4] = [4, 7]. */
2543 ior_max.low = vr0_max.low | vr1_max.low;
2544 ior_max.high = vr0_max.high | vr1_max.high;
2545 if (ior_max.high != 0)
2547 ior_max.low = ~(unsigned HOST_WIDE_INT)0u;
2548 ior_max.high |= ((HOST_WIDE_INT) 1
2549 << floor_log2 (ior_max.high)) - 1;
2551 else if (ior_max.low != 0)
2552 ior_max.low |= ((unsigned HOST_WIDE_INT) 1u
2553 << floor_log2 (ior_max.low)) - 1;
2555 /* Both of these endpoints are conservative. */
2556 min = vrp_int_const_binop (MAX_EXPR, vr0.min, vr1.min);
2557 max = double_int_to_tree (expr_type, ior_max);
2561 set_value_range_to_varying (vr);
2568 /* If either MIN or MAX overflowed, then set the resulting range to
2569 VARYING. But we do accept an overflow infinity
2571 if (min == NULL_TREE
2572 || !is_gimple_min_invariant (min)
2573 || (TREE_OVERFLOW (min) && !is_overflow_infinity (min))
2575 || !is_gimple_min_invariant (max)
2576 || (TREE_OVERFLOW (max) && !is_overflow_infinity (max)))
2578 set_value_range_to_varying (vr);
2584 2) [-INF, +-INF(OVF)]
2585 3) [+-INF(OVF), +INF]
2586 4) [+-INF(OVF), +-INF(OVF)]
2587 We learn nothing when we have INF and INF(OVF) on both sides.
2588 Note that we do accept [-INF, -INF] and [+INF, +INF] without
2590 if ((vrp_val_is_min (min) || is_overflow_infinity (min))
2591 && (vrp_val_is_max (max) || is_overflow_infinity (max)))
2593 set_value_range_to_varying (vr);
2597 cmp = compare_values (min, max);
2598 if (cmp == -2 || cmp == 1)
2600 /* If the new range has its limits swapped around (MIN > MAX),
2601 then the operation caused one of them to wrap around, mark
2602 the new range VARYING. */
2603 set_value_range_to_varying (vr);
2606 set_value_range (vr, type, min, max, NULL);
2610 /* Extract range information from a unary expression EXPR based on
2611 the range of its operand and the expression code. */
2614 extract_range_from_unary_expr (value_range_t *vr, enum tree_code code,
2615 tree type, tree op0)
2619 value_range_t vr0 = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
2621 /* Refuse to operate on certain unary expressions for which we
2622 cannot easily determine a resulting range. */
2623 if (code == FIX_TRUNC_EXPR
2624 || code == FLOAT_EXPR
2625 || code == BIT_NOT_EXPR
2626 || code == CONJ_EXPR)
2628 /* We can still do constant propagation here. */
2629 if ((op0 = op_with_constant_singleton_value_range (op0)) != NULL_TREE)
2631 tree tem = fold_unary (code, type, op0);
2633 && is_gimple_min_invariant (tem)
2634 && !is_overflow_infinity (tem))
2636 set_value_range (vr, VR_RANGE, tem, tem, NULL);
2640 set_value_range_to_varying (vr);
2644 /* Get value ranges for the operand. For constant operands, create
2645 a new value range with the operand to simplify processing. */
2646 if (TREE_CODE (op0) == SSA_NAME)
2647 vr0 = *(get_value_range (op0));
2648 else if (is_gimple_min_invariant (op0))
2649 set_value_range_to_value (&vr0, op0, NULL);
2651 set_value_range_to_varying (&vr0);
2653 /* If VR0 is UNDEFINED, so is the result. */
2654 if (vr0.type == VR_UNDEFINED)
2656 set_value_range_to_undefined (vr);
2660 /* Refuse to operate on symbolic ranges, or if neither operand is
2661 a pointer or integral type. */
2662 if ((!INTEGRAL_TYPE_P (TREE_TYPE (op0))
2663 && !POINTER_TYPE_P (TREE_TYPE (op0)))
2664 || (vr0.type != VR_VARYING
2665 && symbolic_range_p (&vr0)))
2667 set_value_range_to_varying (vr);
2671 /* If the expression involves pointers, we are only interested in
2672 determining if it evaluates to NULL [0, 0] or non-NULL (~[0, 0]). */
2673 if (POINTER_TYPE_P (type) || POINTER_TYPE_P (TREE_TYPE (op0)))
2678 if (range_is_nonnull (&vr0)
2679 || (tree_unary_nonzero_warnv_p (code, type, op0, &sop)
2681 set_value_range_to_nonnull (vr, type);
2682 else if (range_is_null (&vr0))
2683 set_value_range_to_null (vr, type);
2685 set_value_range_to_varying (vr);
2690 /* Handle unary expressions on integer ranges. */
2691 if (CONVERT_EXPR_CODE_P (code)
2692 && INTEGRAL_TYPE_P (type)
2693 && INTEGRAL_TYPE_P (TREE_TYPE (op0)))
2695 tree inner_type = TREE_TYPE (op0);
2696 tree outer_type = type;
2698 /* If VR0 is varying and we increase the type precision, assume
2699 a full range for the following transformation. */
2700 if (vr0.type == VR_VARYING
2701 && TYPE_PRECISION (inner_type) < TYPE_PRECISION (outer_type))
2703 vr0.type = VR_RANGE;
2704 vr0.min = TYPE_MIN_VALUE (inner_type);
2705 vr0.max = TYPE_MAX_VALUE (inner_type);
2708 /* If VR0 is a constant range or anti-range and the conversion is
2709 not truncating we can convert the min and max values and
2710 canonicalize the resulting range. Otherwise we can do the
2711 conversion if the size of the range is less than what the
2712 precision of the target type can represent and the range is
2713 not an anti-range. */
2714 if ((vr0.type == VR_RANGE
2715 || vr0.type == VR_ANTI_RANGE)
2716 && TREE_CODE (vr0.min) == INTEGER_CST
2717 && TREE_CODE (vr0.max) == INTEGER_CST
2718 && (!is_overflow_infinity (vr0.min)
2719 || (vr0.type == VR_RANGE
2720 && TYPE_PRECISION (outer_type) > TYPE_PRECISION (inner_type)
2721 && needs_overflow_infinity (outer_type)
2722 && supports_overflow_infinity (outer_type)))
2723 && (!is_overflow_infinity (vr0.max)
2724 || (vr0.type == VR_RANGE
2725 && TYPE_PRECISION (outer_type) > TYPE_PRECISION (inner_type)
2726 && needs_overflow_infinity (outer_type)
2727 && supports_overflow_infinity (outer_type)))
2728 && (TYPE_PRECISION (outer_type) >= TYPE_PRECISION (inner_type)
2729 || (vr0.type == VR_RANGE
2730 && integer_zerop (int_const_binop (RSHIFT_EXPR,
2731 int_const_binop (MINUS_EXPR, vr0.max, vr0.min, 0),
2732 size_int (TYPE_PRECISION (outer_type)), 0)))))
2734 tree new_min, new_max;
2735 new_min = force_fit_type_double (outer_type,
2736 TREE_INT_CST_LOW (vr0.min),
2737 TREE_INT_CST_HIGH (vr0.min), 0, 0);
2738 new_max = force_fit_type_double (outer_type,
2739 TREE_INT_CST_LOW (vr0.max),
2740 TREE_INT_CST_HIGH (vr0.max), 0, 0);
2741 if (is_overflow_infinity (vr0.min))
2742 new_min = negative_overflow_infinity (outer_type);
2743 if (is_overflow_infinity (vr0.max))
2744 new_max = positive_overflow_infinity (outer_type);
2745 set_and_canonicalize_value_range (vr, vr0.type,
2746 new_min, new_max, NULL);
2750 set_value_range_to_varying (vr);
2754 /* Conversion of a VR_VARYING value to a wider type can result
2755 in a usable range. So wait until after we've handled conversions
2756 before dropping the result to VR_VARYING if we had a source
2757 operand that is VR_VARYING. */
2758 if (vr0.type == VR_VARYING)
2760 set_value_range_to_varying (vr);
2764 /* Apply the operation to each end of the range and see what we end
2766 if (code == NEGATE_EXPR
2767 && !TYPE_UNSIGNED (type))
2769 /* NEGATE_EXPR flips the range around. We need to treat
2770 TYPE_MIN_VALUE specially. */
2771 if (is_positive_overflow_infinity (vr0.max))
2772 min = negative_overflow_infinity (type);
2773 else if (is_negative_overflow_infinity (vr0.max))
2774 min = positive_overflow_infinity (type);
2775 else if (!vrp_val_is_min (vr0.max))
2776 min = fold_unary_to_constant (code, type, vr0.max);
2777 else if (needs_overflow_infinity (type))
2779 if (supports_overflow_infinity (type)
2780 && !is_overflow_infinity (vr0.min)
2781 && !vrp_val_is_min (vr0.min))
2782 min = positive_overflow_infinity (type);
2785 set_value_range_to_varying (vr);
2790 min = TYPE_MIN_VALUE (type);
2792 if (is_positive_overflow_infinity (vr0.min))
2793 max = negative_overflow_infinity (type);
2794 else if (is_negative_overflow_infinity (vr0.min))
2795 max = positive_overflow_infinity (type);
2796 else if (!vrp_val_is_min (vr0.min))
2797 max = fold_unary_to_constant (code, type, vr0.min);
2798 else if (needs_overflow_infinity (type))
2800 if (supports_overflow_infinity (type))
2801 max = positive_overflow_infinity (type);
2804 set_value_range_to_varying (vr);
2809 max = TYPE_MIN_VALUE (type);
2811 else if (code == NEGATE_EXPR
2812 && TYPE_UNSIGNED (type))
2814 if (!range_includes_zero_p (&vr0))
2816 max = fold_unary_to_constant (code, type, vr0.min);
2817 min = fold_unary_to_constant (code, type, vr0.max);
2821 if (range_is_null (&vr0))
2822 set_value_range_to_null (vr, type);
2824 set_value_range_to_varying (vr);
2828 else if (code == ABS_EXPR
2829 && !TYPE_UNSIGNED (type))
2831 /* -TYPE_MIN_VALUE = TYPE_MIN_VALUE with flag_wrapv so we can't get a
2833 if (!TYPE_OVERFLOW_UNDEFINED (type)
2834 && ((vr0.type == VR_RANGE
2835 && vrp_val_is_min (vr0.min))
2836 || (vr0.type == VR_ANTI_RANGE
2837 && !vrp_val_is_min (vr0.min)
2838 && !range_includes_zero_p (&vr0))))
2840 set_value_range_to_varying (vr);
2844 /* ABS_EXPR may flip the range around, if the original range
2845 included negative values. */
2846 if (is_overflow_infinity (vr0.min))
2847 min = positive_overflow_infinity (type);
2848 else if (!vrp_val_is_min (vr0.min))
2849 min = fold_unary_to_constant (code, type, vr0.min);
2850 else if (!needs_overflow_infinity (type))
2851 min = TYPE_MAX_VALUE (type);
2852 else if (supports_overflow_infinity (type))
2853 min = positive_overflow_infinity (type);
2856 set_value_range_to_varying (vr);
2860 if (is_overflow_infinity (vr0.max))
2861 max = positive_overflow_infinity (type);
2862 else if (!vrp_val_is_min (vr0.max))
2863 max = fold_unary_to_constant (code, type, vr0.max);
2864 else if (!needs_overflow_infinity (type))
2865 max = TYPE_MAX_VALUE (type);
2866 else if (supports_overflow_infinity (type)
2867 /* We shouldn't generate [+INF, +INF] as set_value_range
2868 doesn't like this and ICEs. */
2869 && !is_positive_overflow_infinity (min))
2870 max = positive_overflow_infinity (type);
2873 set_value_range_to_varying (vr);
2877 cmp = compare_values (min, max);
2879 /* If a VR_ANTI_RANGEs contains zero, then we have
2880 ~[-INF, min(MIN, MAX)]. */
2881 if (vr0.type == VR_ANTI_RANGE)
2883 if (range_includes_zero_p (&vr0))
2885 /* Take the lower of the two values. */
2889 /* Create ~[-INF, min (abs(MIN), abs(MAX))]
2890 or ~[-INF + 1, min (abs(MIN), abs(MAX))] when
2891 flag_wrapv is set and the original anti-range doesn't include
2892 TYPE_MIN_VALUE, remember -TYPE_MIN_VALUE = TYPE_MIN_VALUE. */
2893 if (TYPE_OVERFLOW_WRAPS (type))
2895 tree type_min_value = TYPE_MIN_VALUE (type);
2897 min = (vr0.min != type_min_value
2898 ? int_const_binop (PLUS_EXPR, type_min_value,
2899 integer_one_node, 0)
2904 if (overflow_infinity_range_p (&vr0))
2905 min = negative_overflow_infinity (type);
2907 min = TYPE_MIN_VALUE (type);
2912 /* All else has failed, so create the range [0, INF], even for
2913 flag_wrapv since TYPE_MIN_VALUE is in the original
2915 vr0.type = VR_RANGE;
2916 min = build_int_cst (type, 0);
2917 if (needs_overflow_infinity (type))
2919 if (supports_overflow_infinity (type))
2920 max = positive_overflow_infinity (type);
2923 set_value_range_to_varying (vr);
2928 max = TYPE_MAX_VALUE (type);
2932 /* If the range contains zero then we know that the minimum value in the
2933 range will be zero. */
2934 else if (range_includes_zero_p (&vr0))
2938 min = build_int_cst (type, 0);
2942 /* If the range was reversed, swap MIN and MAX. */
2953 /* Otherwise, operate on each end of the range. */
2954 min = fold_unary_to_constant (code, type, vr0.min);
2955 max = fold_unary_to_constant (code, type, vr0.max);
2957 if (needs_overflow_infinity (type))
2959 gcc_assert (code != NEGATE_EXPR && code != ABS_EXPR);
2961 /* If both sides have overflowed, we don't know
2963 if ((is_overflow_infinity (vr0.min)
2964 || TREE_OVERFLOW (min))
2965 && (is_overflow_infinity (vr0.max)
2966 || TREE_OVERFLOW (max)))
2968 set_value_range_to_varying (vr);
2972 if (is_overflow_infinity (vr0.min))
2974 else if (TREE_OVERFLOW (min))
2976 if (supports_overflow_infinity (type))
2977 min = (tree_int_cst_sgn (min) >= 0
2978 ? positive_overflow_infinity (TREE_TYPE (min))
2979 : negative_overflow_infinity (TREE_TYPE (min)));
2982 set_value_range_to_varying (vr);
2987 if (is_overflow_infinity (vr0.max))
2989 else if (TREE_OVERFLOW (max))
2991 if (supports_overflow_infinity (type))
2992 max = (tree_int_cst_sgn (max) >= 0
2993 ? positive_overflow_infinity (TREE_TYPE (max))
2994 : negative_overflow_infinity (TREE_TYPE (max)));
2997 set_value_range_to_varying (vr);
3004 cmp = compare_values (min, max);
3005 if (cmp == -2 || cmp == 1)
3007 /* If the new range has its limits swapped around (MIN > MAX),
3008 then the operation caused one of them to wrap around, mark
3009 the new range VARYING. */
3010 set_value_range_to_varying (vr);
3013 set_value_range (vr, vr0.type, min, max, NULL);
3017 /* Extract range information from a conditional expression EXPR based on
3018 the ranges of each of its operands and the expression code. */
3021 extract_range_from_cond_expr (value_range_t *vr, tree expr)
3024 value_range_t vr0 = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
3025 value_range_t vr1 = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
3027 /* Get value ranges for each operand. For constant operands, create
3028 a new value range with the operand to simplify processing. */
3029 op0 = COND_EXPR_THEN (expr);
3030 if (TREE_CODE (op0) == SSA_NAME)
3031 vr0 = *(get_value_range (op0));
3032 else if (is_gimple_min_invariant (op0))
3033 set_value_range_to_value (&vr0, op0, NULL);
3035 set_value_range_to_varying (&vr0);
3037 op1 = COND_EXPR_ELSE (expr);
3038 if (TREE_CODE (op1) == SSA_NAME)
3039 vr1 = *(get_value_range (op1));
3040 else if (is_gimple_min_invariant (op1))
3041 set_value_range_to_value (&vr1, op1, NULL);
3043 set_value_range_to_varying (&vr1);
3045 /* The resulting value range is the union of the operand ranges */
3046 vrp_meet (&vr0, &vr1);
3047 copy_value_range (vr, &vr0);
3051 /* Extract range information from a comparison expression EXPR based
3052 on the range of its operand and the expression code. */
3055 extract_range_from_comparison (value_range_t *vr, enum tree_code code,
3056 tree type, tree op0, tree op1)
3061 val = vrp_evaluate_conditional_warnv_with_ops (code, op0, op1, false, &sop,
3064 /* A disadvantage of using a special infinity as an overflow
3065 representation is that we lose the ability to record overflow
3066 when we don't have an infinity. So we have to ignore a result
3067 which relies on overflow. */
3069 if (val && !is_overflow_infinity (val) && !sop)
3071 /* Since this expression was found on the RHS of an assignment,
3072 its type may be different from _Bool. Convert VAL to EXPR's
3074 val = fold_convert (type, val);
3075 if (is_gimple_min_invariant (val))
3076 set_value_range_to_value (vr, val, vr->equiv);
3078 set_value_range (vr, VR_RANGE, val, val, vr->equiv);
3081 /* The result of a comparison is always true or false. */
3082 set_value_range_to_truthvalue (vr, type);
3085 /* Try to derive a nonnegative or nonzero range out of STMT relying
3086 primarily on generic routines in fold in conjunction with range data.
3087 Store the result in *VR */
3090 extract_range_basic (value_range_t *vr, gimple stmt)
3093 tree type = gimple_expr_type (stmt);
3095 if (INTEGRAL_TYPE_P (type)
3096 && gimple_stmt_nonnegative_warnv_p (stmt, &sop))
3097 set_value_range_to_nonnegative (vr, type,
3098 sop || stmt_overflow_infinity (stmt));
3099 else if (vrp_stmt_computes_nonzero (stmt, &sop)
3101 set_value_range_to_nonnull (vr, type);
3103 set_value_range_to_varying (vr);
3107 /* Try to compute a useful range out of assignment STMT and store it
3111 extract_range_from_assignment (value_range_t *vr, gimple stmt)
3113 enum tree_code code = gimple_assign_rhs_code (stmt);
3115 if (code == ASSERT_EXPR)
3116 extract_range_from_assert (vr, gimple_assign_rhs1 (stmt));
3117 else if (code == SSA_NAME)
3118 extract_range_from_ssa_name (vr, gimple_assign_rhs1 (stmt));
3119 else if (TREE_CODE_CLASS (code) == tcc_binary
3120 || code == TRUTH_AND_EXPR
3121 || code == TRUTH_OR_EXPR
3122 || code == TRUTH_XOR_EXPR)
3123 extract_range_from_binary_expr (vr, gimple_assign_rhs_code (stmt),
3124 gimple_expr_type (stmt),
3125 gimple_assign_rhs1 (stmt),
3126 gimple_assign_rhs2 (stmt));
3127 else if (TREE_CODE_CLASS (code) == tcc_unary)
3128 extract_range_from_unary_expr (vr, gimple_assign_rhs_code (stmt),
3129 gimple_expr_type (stmt),
3130 gimple_assign_rhs1 (stmt));
3131 else if (code == COND_EXPR)
3132 extract_range_from_cond_expr (vr, gimple_assign_rhs1 (stmt));
3133 else if (TREE_CODE_CLASS (code) == tcc_comparison)
3134 extract_range_from_comparison (vr, gimple_assign_rhs_code (stmt),
3135 gimple_expr_type (stmt),
3136 gimple_assign_rhs1 (stmt),
3137 gimple_assign_rhs2 (stmt));
3138 else if (get_gimple_rhs_class (code) == GIMPLE_SINGLE_RHS
3139 && is_gimple_min_invariant (gimple_assign_rhs1 (stmt)))
3140 set_value_range_to_value (vr, gimple_assign_rhs1 (stmt), NULL);
3142 set_value_range_to_varying (vr);
3144 if (vr->type == VR_VARYING)
3145 extract_range_basic (vr, stmt);
3148 /* Given a range VR, a LOOP and a variable VAR, determine whether it
3149 would be profitable to adjust VR using scalar evolution information
3150 for VAR. If so, update VR with the new limits. */
3153 adjust_range_with_scev (value_range_t *vr, struct loop *loop,
3154 gimple stmt, tree var)
3156 tree init, step, chrec, tmin, tmax, min, max, type;
3157 enum ev_direction dir;
3159 /* TODO. Don't adjust anti-ranges. An anti-range may provide
3160 better opportunities than a regular range, but I'm not sure. */
3161 if (vr->type == VR_ANTI_RANGE)
3164 chrec = instantiate_parameters (loop, analyze_scalar_evolution (loop, var));
3166 /* Like in PR19590, scev can return a constant function. */
3167 if (is_gimple_min_invariant (chrec))
3169 set_value_range_to_value (vr, chrec, vr->equiv);
3173 if (TREE_CODE (chrec) != POLYNOMIAL_CHREC)
3176 init = initial_condition_in_loop_num (chrec, loop->num);
3177 step = evolution_part_in_loop_num (chrec, loop->num);
3179 /* If STEP is symbolic, we can't know whether INIT will be the
3180 minimum or maximum value in the range. Also, unless INIT is
3181 a simple expression, compare_values and possibly other functions
3182 in tree-vrp won't be able to handle it. */
3183 if (step == NULL_TREE
3184 || !is_gimple_min_invariant (step)
3185 || !valid_value_p (init))
3188 dir = scev_direction (chrec);
3189 if (/* Do not adjust ranges if we do not know whether the iv increases
3190 or decreases, ... */
3191 dir == EV_DIR_UNKNOWN
3192 /* ... or if it may wrap. */
3193 || scev_probably_wraps_p (init, step, stmt, get_chrec_loop (chrec),
3197 /* We use TYPE_MIN_VALUE and TYPE_MAX_VALUE here instead of
3198 negative_overflow_infinity and positive_overflow_infinity,
3199 because we have concluded that the loop probably does not
3202 type = TREE_TYPE (var);
3203 if (POINTER_TYPE_P (type) || !TYPE_MIN_VALUE (type))
3204 tmin = lower_bound_in_type (type, type);
3206 tmin = TYPE_MIN_VALUE (type);
3207 if (POINTER_TYPE_P (type) || !TYPE_MAX_VALUE (type))
3208 tmax = upper_bound_in_type (type, type);
3210 tmax = TYPE_MAX_VALUE (type);
3212 if (vr->type == VR_VARYING || vr->type == VR_UNDEFINED)
3217 /* For VARYING or UNDEFINED ranges, just about anything we get
3218 from scalar evolutions should be better. */
3220 if (dir == EV_DIR_DECREASES)
3225 /* If we would create an invalid range, then just assume we
3226 know absolutely nothing. This may be over-conservative,
3227 but it's clearly safe, and should happen only in unreachable
3228 parts of code, or for invalid programs. */
3229 if (compare_values (min, max) == 1)
3232 set_value_range (vr, VR_RANGE, min, max, vr->equiv);
3234 else if (vr->type == VR_RANGE)
3239 if (dir == EV_DIR_DECREASES)
3241 /* INIT is the maximum value. If INIT is lower than VR->MAX
3242 but no smaller than VR->MIN, set VR->MAX to INIT. */
3243 if (compare_values (init, max) == -1)
3247 /* If we just created an invalid range with the minimum
3248 greater than the maximum, we fail conservatively.
3249 This should happen only in unreachable
3250 parts of code, or for invalid programs. */
3251 if (compare_values (min, max) == 1)
3255 /* According to the loop information, the variable does not
3256 overflow. If we think it does, probably because of an
3257 overflow due to arithmetic on a different INF value,
3259 if (is_negative_overflow_infinity (min))
3264 /* If INIT is bigger than VR->MIN, set VR->MIN to INIT. */
3265 if (compare_values (init, min) == 1)
3269 /* Again, avoid creating invalid range by failing. */
3270 if (compare_values (min, max) == 1)
3274 if (is_positive_overflow_infinity (max))
3278 set_value_range (vr, VR_RANGE, min, max, vr->equiv);
3282 /* Return true if VAR may overflow at STMT. This checks any available
3283 loop information to see if we can determine that VAR does not
3287 vrp_var_may_overflow (tree var, gimple stmt)
3290 tree chrec, init, step;
3292 if (current_loops == NULL)
3295 l = loop_containing_stmt (stmt);
3300 chrec = instantiate_parameters (l, analyze_scalar_evolution (l, var));
3301 if (TREE_CODE (chrec) != POLYNOMIAL_CHREC)
3304 init = initial_condition_in_loop_num (chrec, l->num);
3305 step = evolution_part_in_loop_num (chrec, l->num);
3307 if (step == NULL_TREE
3308 || !is_gimple_min_invariant (step)
3309 || !valid_value_p (init))
3312 /* If we get here, we know something useful about VAR based on the
3313 loop information. If it wraps, it may overflow. */
3315 if (scev_probably_wraps_p (init, step, stmt, get_chrec_loop (chrec),
3319 if (dump_file && (dump_flags & TDF_DETAILS) != 0)
3321 print_generic_expr (dump_file, var, 0);
3322 fprintf (dump_file, ": loop information indicates does not overflow\n");
3329 /* Given two numeric value ranges VR0, VR1 and a comparison code COMP:
3331 - Return BOOLEAN_TRUE_NODE if VR0 COMP VR1 always returns true for
3332 all the values in the ranges.
3334 - Return BOOLEAN_FALSE_NODE if the comparison always returns false.
3336 - Return NULL_TREE if it is not always possible to determine the
3337 value of the comparison.
3339 Also set *STRICT_OVERFLOW_P to indicate whether a range with an
3340 overflow infinity was used in the test. */
3344 compare_ranges (enum tree_code comp, value_range_t *vr0, value_range_t *vr1,
3345 bool *strict_overflow_p)
3347 /* VARYING or UNDEFINED ranges cannot be compared. */
3348 if (vr0->type == VR_VARYING
3349 || vr0->type == VR_UNDEFINED
3350 || vr1->type == VR_VARYING
3351 || vr1->type == VR_UNDEFINED)
3354 /* Anti-ranges need to be handled separately. */
3355 if (vr0->type == VR_ANTI_RANGE || vr1->type == VR_ANTI_RANGE)
3357 /* If both are anti-ranges, then we cannot compute any
3359 if (vr0->type == VR_ANTI_RANGE && vr1->type == VR_ANTI_RANGE)
3362 /* These comparisons are never statically computable. */
3369 /* Equality can be computed only between a range and an
3370 anti-range. ~[VAL1, VAL2] == [VAL1, VAL2] is always false. */
3371 if (vr0->type == VR_RANGE)
3373 /* To simplify processing, make VR0 the anti-range. */
3374 value_range_t *tmp = vr0;
3379 gcc_assert (comp == NE_EXPR || comp == EQ_EXPR);
3381 if (compare_values_warnv (vr0->min, vr1->min, strict_overflow_p) == 0
3382 && compare_values_warnv (vr0->max, vr1->max, strict_overflow_p) == 0)
3383 return (comp == NE_EXPR) ? boolean_true_node : boolean_false_node;
3388 if (!usable_range_p (vr0, strict_overflow_p)
3389 || !usable_range_p (vr1, strict_overflow_p))
3392 /* Simplify processing. If COMP is GT_EXPR or GE_EXPR, switch the
3393 operands around and change the comparison code. */
3394 if (comp == GT_EXPR || comp == GE_EXPR)
3397 comp = (comp == GT_EXPR) ? LT_EXPR : LE_EXPR;
3403 if (comp == EQ_EXPR)
3405 /* Equality may only be computed if both ranges represent
3406 exactly one value. */
3407 if (compare_values_warnv (vr0->min, vr0->max, strict_overflow_p) == 0
3408 && compare_values_warnv (vr1->min, vr1->max, strict_overflow_p) == 0)
3410 int cmp_min = compare_values_warnv (vr0->min, vr1->min,
3412 int cmp_max = compare_values_warnv (vr0->max, vr1->max,
3414 if (cmp_min == 0 && cmp_max == 0)
3415 return boolean_true_node;
3416 else if (cmp_min != -2 && cmp_max != -2)
3417 return boolean_false_node;
3419 /* If [V0_MIN, V1_MAX] < [V1_MIN, V1_MAX] then V0 != V1. */
3420 else if (compare_values_warnv (vr0->min, vr1->max,
3421 strict_overflow_p) == 1
3422 || compare_values_warnv (vr1->min, vr0->max,
3423 strict_overflow_p) == 1)
3424 return boolean_false_node;
3428 else if (comp == NE_EXPR)
3432 /* If VR0 is completely to the left or completely to the right
3433 of VR1, they are always different. Notice that we need to
3434 make sure that both comparisons yield similar results to
3435 avoid comparing values that cannot be compared at
3437 cmp1 = compare_values_warnv (vr0->max, vr1->min, strict_overflow_p);
3438 cmp2 = compare_values_warnv (vr0->min, vr1->max, strict_overflow_p);
3439 if ((cmp1 == -1 && cmp2 == -1) || (cmp1 == 1 && cmp2 == 1))
3440 return boolean_true_node;
3442 /* If VR0 and VR1 represent a single value and are identical,
3444 else if (compare_values_warnv (vr0->min, vr0->max,
3445 strict_overflow_p) == 0
3446 && compare_values_warnv (vr1->min, vr1->max,
3447 strict_overflow_p) == 0
3448 && compare_values_warnv (vr0->min, vr1->min,
3449 strict_overflow_p) == 0
3450 && compare_values_warnv (vr0->max, vr1->max,
3451 strict_overflow_p) == 0)
3452 return boolean_false_node;
3454 /* Otherwise, they may or may not be different. */
3458 else if (comp == LT_EXPR || comp == LE_EXPR)
3462 /* If VR0 is to the left of VR1, return true. */
3463 tst = compare_values_warnv (vr0->max, vr1->min, strict_overflow_p);
3464 if ((comp == LT_EXPR && tst == -1)
3465 || (comp == LE_EXPR && (tst == -1 || tst == 0)))
3467 if (overflow_infinity_range_p (vr0)
3468 || overflow_infinity_range_p (vr1))
3469 *strict_overflow_p = true;
3470 return boolean_true_node;
3473 /* If VR0 is to the right of VR1, return false. */
3474 tst = compare_values_warnv (vr0->min, vr1->max, strict_overflow_p);
3475 if ((comp == LT_EXPR && (tst == 0 || tst == 1))
3476 || (comp == LE_EXPR && tst == 1))
3478 if (overflow_infinity_range_p (vr0)
3479 || overflow_infinity_range_p (vr1))
3480 *strict_overflow_p = true;
3481 return boolean_false_node;
3484 /* Otherwise, we don't know. */
3492 /* Given a value range VR, a value VAL and a comparison code COMP, return
3493 BOOLEAN_TRUE_NODE if VR COMP VAL always returns true for all the
3494 values in VR. Return BOOLEAN_FALSE_NODE if the comparison
3495 always returns false. Return NULL_TREE if it is not always
3496 possible to determine the value of the comparison. Also set
3497 *STRICT_OVERFLOW_P to indicate whether a range with an overflow
3498 infinity was used in the test. */
3501 compare_range_with_value (enum tree_code comp, value_range_t *vr, tree val,
3502 bool *strict_overflow_p)
3504 if (vr->type == VR_VARYING || vr->type == VR_UNDEFINED)
3507 /* Anti-ranges need to be handled separately. */
3508 if (vr->type == VR_ANTI_RANGE)
3510 /* For anti-ranges, the only predicates that we can compute at
3511 compile time are equality and inequality. */
3518 /* ~[VAL_1, VAL_2] OP VAL is known if VAL_1 <= VAL <= VAL_2. */
3519 if (value_inside_range (val, vr) == 1)
3520 return (comp == NE_EXPR) ? boolean_true_node : boolean_false_node;
3525 if (!usable_range_p (vr, strict_overflow_p))
3528 if (comp == EQ_EXPR)
3530 /* EQ_EXPR may only be computed if VR represents exactly
3532 if (compare_values_warnv (vr->min, vr->max, strict_overflow_p) == 0)
3534 int cmp = compare_values_warnv (vr->min, val, strict_overflow_p);
3536 return boolean_true_node;
3537 else if (cmp == -1 || cmp == 1 || cmp == 2)
3538 return boolean_false_node;
3540 else if (compare_values_warnv (val, vr->min, strict_overflow_p) == -1
3541 || compare_values_warnv (vr->max, val, strict_overflow_p) == -1)
3542 return boolean_false_node;
3546 else if (comp == NE_EXPR)
3548 /* If VAL is not inside VR, then they are always different. */
3549 if (compare_values_warnv (vr->max, val, strict_overflow_p) == -1
3550 || compare_values_warnv (vr->min, val, strict_overflow_p) == 1)
3551 return boolean_true_node;
3553 /* If VR represents exactly one value equal to VAL, then return
3555 if (compare_values_warnv (vr->min, vr->max, strict_overflow_p) == 0
3556 && compare_values_warnv (vr->min, val, strict_overflow_p) == 0)
3557 return boolean_false_node;
3559 /* Otherwise, they may or may not be different. */
3562 else if (comp == LT_EXPR || comp == LE_EXPR)
3566 /* If VR is to the left of VAL, return true. */
3567 tst = compare_values_warnv (vr->max, val, strict_overflow_p);
3568 if ((comp == LT_EXPR && tst == -1)
3569 || (comp == LE_EXPR && (tst == -1 || tst == 0)))
3571 if (overflow_infinity_range_p (vr))
3572 *strict_overflow_p = true;
3573 return boolean_true_node;
3576 /* If VR is to the right of VAL, return false. */
3577 tst = compare_values_warnv (vr->min, val, strict_overflow_p);
3578 if ((comp == LT_EXPR && (tst == 0 || tst == 1))
3579 || (comp == LE_EXPR && tst == 1))
3581 if (overflow_infinity_range_p (vr))
3582 *strict_overflow_p = true;
3583 return boolean_false_node;
3586 /* Otherwise, we don't know. */
3589 else if (comp == GT_EXPR || comp == GE_EXPR)
3593 /* If VR is to the right of VAL, return true. */
3594 tst = compare_values_warnv (vr->min, val, strict_overflow_p);
3595 if ((comp == GT_EXPR && tst == 1)
3596 || (comp == GE_EXPR && (tst == 0 || tst == 1)))
3598 if (overflow_infinity_range_p (vr))
3599 *strict_overflow_p = true;
3600 return boolean_true_node;
3603 /* If VR is to the left of VAL, return false. */
3604 tst = compare_values_warnv (vr->max, val, strict_overflow_p);
3605 if ((comp == GT_EXPR && (tst == -1 || tst == 0))
3606 || (comp == GE_EXPR && tst == -1))
3608 if (overflow_infinity_range_p (vr))
3609 *strict_overflow_p = true;
3610 return boolean_false_node;
3613 /* Otherwise, we don't know. */
3621 /* Debugging dumps. */
3623 void dump_value_range (FILE *, value_range_t *);
3624 void debug_value_range (value_range_t *);
3625 void dump_all_value_ranges (FILE *);
3626 void debug_all_value_ranges (void);
3627 void dump_vr_equiv (FILE *, bitmap);
3628 void debug_vr_equiv (bitmap);
3631 /* Dump value range VR to FILE. */
3634 dump_value_range (FILE *file, value_range_t *vr)
3637 fprintf (file, "[]");
3638 else if (vr->type == VR_UNDEFINED)
3639 fprintf (file, "UNDEFINED");
3640 else if (vr->type == VR_RANGE || vr->type == VR_ANTI_RANGE)
3642 tree type = TREE_TYPE (vr->min);
3644 fprintf (file, "%s[", (vr->type == VR_ANTI_RANGE) ? "~" : "");
3646 if (is_negative_overflow_infinity (vr->min))
3647 fprintf (file, "-INF(OVF)");
3648 else if (INTEGRAL_TYPE_P (type)
3649 && !TYPE_UNSIGNED (type)
3650 && vrp_val_is_min (vr->min))
3651 fprintf (file, "-INF");
3653 print_generic_expr (file, vr->min, 0);
3655 fprintf (file, ", ");
3657 if (is_positive_overflow_infinity (vr->max))
3658 fprintf (file, "+INF(OVF)");
3659 else if (INTEGRAL_TYPE_P (type)
3660 && vrp_val_is_max (vr->max))
3661 fprintf (file, "+INF");
3663 print_generic_expr (file, vr->max, 0);
3665 fprintf (file, "]");
3672 fprintf (file, " EQUIVALENCES: { ");
3674 EXECUTE_IF_SET_IN_BITMAP (vr->equiv, 0, i, bi)
3676 print_generic_expr (file, ssa_name (i), 0);
3677 fprintf (file, " ");
3681 fprintf (file, "} (%u elements)", c);
3684 else if (vr->type == VR_VARYING)
3685 fprintf (file, "VARYING");
3687 fprintf (file, "INVALID RANGE");
3691 /* Dump value range VR to stderr. */
3694 debug_value_range (value_range_t *vr)
3696 dump_value_range (stderr, vr);
3697 fprintf (stderr, "\n");
3701 /* Dump value ranges of all SSA_NAMEs to FILE. */
3704 dump_all_value_ranges (FILE *file)
3708 for (i = 0; i < num_ssa_names; i++)
3712 print_generic_expr (file, ssa_name (i), 0);
3713 fprintf (file, ": ");
3714 dump_value_range (file, vr_value[i]);
3715 fprintf (file, "\n");
3719 fprintf (file, "\n");
3723 /* Dump all value ranges to stderr. */
3726 debug_all_value_ranges (void)
3728 dump_all_value_ranges (stderr);
3732 /* Given a COND_EXPR COND of the form 'V OP W', and an SSA name V,
3733 create a new SSA name N and return the assertion assignment
3734 'V = ASSERT_EXPR <V, V OP W>'. */
3737 build_assert_expr_for (tree cond, tree v)
3742 gcc_assert (TREE_CODE (v) == SSA_NAME);
3743 n = duplicate_ssa_name (v, NULL);
3745 if (COMPARISON_CLASS_P (cond))
3747 tree a = build2 (ASSERT_EXPR, TREE_TYPE (v), v, cond);
3748 assertion = gimple_build_assign (n, a);
3750 else if (TREE_CODE (cond) == TRUTH_NOT_EXPR)
3752 /* Given !V, build the assignment N = false. */
3753 tree op0 = TREE_OPERAND (cond, 0);
3754 gcc_assert (op0 == v);
3755 assertion = gimple_build_assign (n, boolean_false_node);
3757 else if (TREE_CODE (cond) == SSA_NAME)
3759 /* Given V, build the assignment N = true. */
3760 gcc_assert (v == cond);
3761 assertion = gimple_build_assign (n, boolean_true_node);
3766 SSA_NAME_DEF_STMT (n) = assertion;
3768 /* The new ASSERT_EXPR, creates a new SSA name that replaces the
3769 operand of the ASSERT_EXPR. Register the new name and the old one
3770 in the replacement table so that we can fix the SSA web after
3771 adding all the ASSERT_EXPRs. */
3772 register_new_name_mapping (n, v);
3778 /* Return false if EXPR is a predicate expression involving floating
3782 fp_predicate (gimple stmt)
3784 GIMPLE_CHECK (stmt, GIMPLE_COND);
3786 return FLOAT_TYPE_P (TREE_TYPE (gimple_cond_lhs (stmt)));
3790 /* If the range of values taken by OP can be inferred after STMT executes,
3791 return the comparison code (COMP_CODE_P) and value (VAL_P) that
3792 describes the inferred range. Return true if a range could be
3796 infer_value_range (gimple stmt, tree op, enum tree_code *comp_code_p, tree *val_p)
3799 *comp_code_p = ERROR_MARK;
3801 /* Do not attempt to infer anything in names that flow through
3803 if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (op))
3806 /* Similarly, don't infer anything from statements that may throw
3808 if (stmt_could_throw_p (stmt))
3811 /* If STMT is the last statement of a basic block with no
3812 successors, there is no point inferring anything about any of its
3813 operands. We would not be able to find a proper insertion point
3814 for the assertion, anyway. */
3815 if (stmt_ends_bb_p (stmt) && EDGE_COUNT (gimple_bb (stmt)->succs) == 0)
3818 /* We can only assume that a pointer dereference will yield
3819 non-NULL if -fdelete-null-pointer-checks is enabled. */
3820 if (flag_delete_null_pointer_checks
3821 && POINTER_TYPE_P (TREE_TYPE (op))
3822 && gimple_code (stmt) != GIMPLE_ASM)
3824 unsigned num_uses, num_loads, num_stores;
3826 count_uses_and_derefs (op, stmt, &num_uses, &num_loads, &num_stores);
3827 if (num_loads + num_stores > 0)
3829 *val_p = build_int_cst (TREE_TYPE (op), 0);
3830 *comp_code_p = NE_EXPR;
3839 void dump_asserts_for (FILE *, tree);
3840 void debug_asserts_for (tree);
3841 void dump_all_asserts (FILE *);
3842 void debug_all_asserts (void);
3844 /* Dump all the registered assertions for NAME to FILE. */
3847 dump_asserts_for (FILE *file, tree name)
3851 fprintf (file, "Assertions to be inserted for ");
3852 print_generic_expr (file, name, 0);
3853 fprintf (file, "\n");
3855 loc = asserts_for[SSA_NAME_VERSION (name)];
3858 fprintf (file, "\t");
3859 print_gimple_stmt (file, gsi_stmt (loc->si), 0, 0);
3860 fprintf (file, "\n\tBB #%d", loc->bb->index);
3863 fprintf (file, "\n\tEDGE %d->%d", loc->e->src->index,
3864 loc->e->dest->index);
3865 dump_edge_info (file, loc->e, 0);
3867 fprintf (file, "\n\tPREDICATE: ");
3868 print_generic_expr (file, name, 0);
3869 fprintf (file, " %s ", tree_code_name[(int)loc->comp_code]);
3870 print_generic_expr (file, loc->val, 0);
3871 fprintf (file, "\n\n");
3875 fprintf (file, "\n");
3879 /* Dump all the registered assertions for NAME to stderr. */
3882 debug_asserts_for (tree name)
3884 dump_asserts_for (stderr, name);
3888 /* Dump all the registered assertions for all the names to FILE. */
3891 dump_all_asserts (FILE *file)
3896 fprintf (file, "\nASSERT_EXPRs to be inserted\n\n");
3897 EXECUTE_IF_SET_IN_BITMAP (need_assert_for, 0, i, bi)
3898 dump_asserts_for (file, ssa_name (i));
3899 fprintf (file, "\n");
3903 /* Dump all the registered assertions for all the names to stderr. */
3906 debug_all_asserts (void)
3908 dump_all_asserts (stderr);
3912 /* If NAME doesn't have an ASSERT_EXPR registered for asserting
3913 'EXPR COMP_CODE VAL' at a location that dominates block BB or
3914 E->DEST, then register this location as a possible insertion point
3915 for ASSERT_EXPR <NAME, EXPR COMP_CODE VAL>.
3917 BB, E and SI provide the exact insertion point for the new
3918 ASSERT_EXPR. If BB is NULL, then the ASSERT_EXPR is to be inserted
3919 on edge E. Otherwise, if E is NULL, the ASSERT_EXPR is inserted on
3920 BB. If SI points to a COND_EXPR or a SWITCH_EXPR statement, then E
3921 must not be NULL. */
3924 register_new_assert_for (tree name, tree expr,
3925 enum tree_code comp_code,
3929 gimple_stmt_iterator si)
3931 assert_locus_t n, loc, last_loc;
3932 basic_block dest_bb;
3934 #if defined ENABLE_CHECKING
3935 gcc_assert (bb == NULL || e == NULL);
3938 gcc_assert (gimple_code (gsi_stmt (si)) != GIMPLE_COND
3939 && gimple_code (gsi_stmt (si)) != GIMPLE_SWITCH);
3942 /* Never build an assert comparing against an integer constant with
3943 TREE_OVERFLOW set. This confuses our undefined overflow warning
3945 if (TREE_CODE (val) == INTEGER_CST
3946 && TREE_OVERFLOW (val))
3947 val = build_int_cst_wide (TREE_TYPE (val),
3948 TREE_INT_CST_LOW (val), TREE_INT_CST_HIGH (val));
3950 /* The new assertion A will be inserted at BB or E. We need to
3951 determine if the new location is dominated by a previously
3952 registered location for A. If we are doing an edge insertion,
3953 assume that A will be inserted at E->DEST. Note that this is not
3956 If E is a critical edge, it will be split. But even if E is
3957 split, the new block will dominate the same set of blocks that
3960 The reverse, however, is not true, blocks dominated by E->DEST
3961 will not be dominated by the new block created to split E. So,
3962 if the insertion location is on a critical edge, we will not use
3963 the new location to move another assertion previously registered
3964 at a block dominated by E->DEST. */
3965 dest_bb = (bb) ? bb : e->dest;
3967 /* If NAME already has an ASSERT_EXPR registered for COMP_CODE and
3968 VAL at a block dominating DEST_BB, then we don't need to insert a new
3969 one. Similarly, if the same assertion already exists at a block
3970 dominated by DEST_BB and the new location is not on a critical
3971 edge, then update the existing location for the assertion (i.e.,
3972 move the assertion up in the dominance tree).
3974 Note, this is implemented as a simple linked list because there
3975 should not be more than a handful of assertions registered per
3976 name. If this becomes a performance problem, a table hashed by
3977 COMP_CODE and VAL could be implemented. */
3978 loc = asserts_for[SSA_NAME_VERSION (name)];
3982 if (loc->comp_code == comp_code
3984 || operand_equal_p (loc->val, val, 0))
3985 && (loc->expr == expr
3986 || operand_equal_p (loc->expr, expr, 0)))
3988 /* If the assertion NAME COMP_CODE VAL has already been
3989 registered at a basic block that dominates DEST_BB, then
3990 we don't need to insert the same assertion again. Note
3991 that we don't check strict dominance here to avoid
3992 replicating the same assertion inside the same basic
3993 block more than once (e.g., when a pointer is
3994 dereferenced several times inside a block).
3996 An exception to this rule are edge insertions. If the
3997 new assertion is to be inserted on edge E, then it will
3998 dominate all the other insertions that we may want to
3999 insert in DEST_BB. So, if we are doing an edge
4000 insertion, don't do this dominance check. */
4002 && dominated_by_p (CDI_DOMINATORS, dest_bb, loc->bb))
4005 /* Otherwise, if E is not a critical edge and DEST_BB
4006 dominates the existing location for the assertion, move
4007 the assertion up in the dominance tree by updating its
4008 location information. */
4009 if ((e == NULL || !EDGE_CRITICAL_P (e))
4010 && dominated_by_p (CDI_DOMINATORS, loc->bb, dest_bb))
4019 /* Update the last node of the list and move to the next one. */
4024 /* If we didn't find an assertion already registered for
4025 NAME COMP_CODE VAL, add a new one at the end of the list of
4026 assertions associated with NAME. */
4027 n = XNEW (struct assert_locus_d);
4031 n->comp_code = comp_code;
4039 asserts_for[SSA_NAME_VERSION (name)] = n;
4041 bitmap_set_bit (need_assert_for, SSA_NAME_VERSION (name));
4044 /* (COND_OP0 COND_CODE COND_OP1) is a predicate which uses NAME.
4045 Extract a suitable test code and value and store them into *CODE_P and
4046 *VAL_P so the predicate is normalized to NAME *CODE_P *VAL_P.
4048 If no extraction was possible, return FALSE, otherwise return TRUE.
4050 If INVERT is true, then we invert the result stored into *CODE_P. */
4053 extract_code_and_val_from_cond_with_ops (tree name, enum tree_code cond_code,
4054 tree cond_op0, tree cond_op1,
4055 bool invert, enum tree_code *code_p,
4058 enum tree_code comp_code;
4061 /* Otherwise, we have a comparison of the form NAME COMP VAL
4062 or VAL COMP NAME. */
4063 if (name == cond_op1)
4065 /* If the predicate is of the form VAL COMP NAME, flip
4066 COMP around because we need to register NAME as the
4067 first operand in the predicate. */
4068 comp_code = swap_tree_comparison (cond_code);
4073 /* The comparison is of the form NAME COMP VAL, so the
4074 comparison code remains unchanged. */
4075 comp_code = cond_code;
4079 /* Invert the comparison code as necessary. */
4081 comp_code = invert_tree_comparison (comp_code, 0);
4083 /* VRP does not handle float types. */
4084 if (SCALAR_FLOAT_TYPE_P (TREE_TYPE (val)))
4087 /* Do not register always-false predicates.
4088 FIXME: this works around a limitation in fold() when dealing with
4089 enumerations. Given 'enum { N1, N2 } x;', fold will not
4090 fold 'if (x > N2)' to 'if (0)'. */
4091 if ((comp_code == GT_EXPR || comp_code == LT_EXPR)
4092 && INTEGRAL_TYPE_P (TREE_TYPE (val)))
4094 tree min = TYPE_MIN_VALUE (TREE_TYPE (val));
4095 tree max = TYPE_MAX_VALUE (TREE_TYPE (val));
4097 if (comp_code == GT_EXPR
4099 || compare_values (val, max) == 0))
4102 if (comp_code == LT_EXPR
4104 || compare_values (val, min) == 0))
4107 *code_p = comp_code;
4112 /* Try to register an edge assertion for SSA name NAME on edge E for
4113 the condition COND contributing to the conditional jump pointed to by BSI.
4114 Invert the condition COND if INVERT is true.
4115 Return true if an assertion for NAME could be registered. */
4118 register_edge_assert_for_2 (tree name, edge e, gimple_stmt_iterator bsi,
4119 enum tree_code cond_code,
4120 tree cond_op0, tree cond_op1, bool invert)
4123 enum tree_code comp_code;
4124 bool retval = false;
4126 if (!extract_code_and_val_from_cond_with_ops (name, cond_code,
4129 invert, &comp_code, &val))
4132 /* Only register an ASSERT_EXPR if NAME was found in the sub-graph
4133 reachable from E. */
4134 if (live_on_edge (e, name)
4135 && !has_single_use (name))
4137 register_new_assert_for (name, name, comp_code, val, NULL, e, bsi);
4141 /* In the case of NAME <= CST and NAME being defined as
4142 NAME = (unsigned) NAME2 + CST2 we can assert NAME2 >= -CST2
4143 and NAME2 <= CST - CST2. We can do the same for NAME > CST.
4144 This catches range and anti-range tests. */
4145 if ((comp_code == LE_EXPR
4146 || comp_code == GT_EXPR)
4147 && TREE_CODE (val) == INTEGER_CST
4148 && TYPE_UNSIGNED (TREE_TYPE (val)))
4150 gimple def_stmt = SSA_NAME_DEF_STMT (name);
4151 tree cst2 = NULL_TREE, name2 = NULL_TREE, name3 = NULL_TREE;
4153 /* Extract CST2 from the (optional) addition. */
4154 if (is_gimple_assign (def_stmt)
4155 && gimple_assign_rhs_code (def_stmt) == PLUS_EXPR)
4157 name2 = gimple_assign_rhs1 (def_stmt);
4158 cst2 = gimple_assign_rhs2 (def_stmt);
4159 if (TREE_CODE (name2) == SSA_NAME
4160 && TREE_CODE (cst2) == INTEGER_CST)
4161 def_stmt = SSA_NAME_DEF_STMT (name2);
4164 /* Extract NAME2 from the (optional) sign-changing cast. */
4165 if (gimple_assign_cast_p (def_stmt))
4167 if (CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (def_stmt))
4168 && ! TYPE_UNSIGNED (TREE_TYPE (gimple_assign_rhs1 (def_stmt)))
4169 && (TYPE_PRECISION (gimple_expr_type (def_stmt))
4170 == TYPE_PRECISION (TREE_TYPE (gimple_assign_rhs1 (def_stmt)))))
4171 name3 = gimple_assign_rhs1 (def_stmt);
4174 /* If name3 is used later, create an ASSERT_EXPR for it. */
4175 if (name3 != NULL_TREE
4176 && TREE_CODE (name3) == SSA_NAME
4177 && (cst2 == NULL_TREE
4178 || TREE_CODE (cst2) == INTEGER_CST)
4179 && INTEGRAL_TYPE_P (TREE_TYPE (name3))
4180 && live_on_edge (e, name3)
4181 && !has_single_use (name3))
4185 /* Build an expression for the range test. */
4186 tmp = build1 (NOP_EXPR, TREE_TYPE (name), name3);
4187 if (cst2 != NULL_TREE)
4188 tmp = build2 (PLUS_EXPR, TREE_TYPE (name), tmp, cst2);
4192 fprintf (dump_file, "Adding assert for ");
4193 print_generic_expr (dump_file, name3, 0);
4194 fprintf (dump_file, " from ");
4195 print_generic_expr (dump_file, tmp, 0);
4196 fprintf (dump_file, "\n");
4199 register_new_assert_for (name3, tmp, comp_code, val, NULL, e, bsi);
4204 /* If name2 is used later, create an ASSERT_EXPR for it. */
4205 if (name2 != NULL_TREE
4206 && TREE_CODE (name2) == SSA_NAME
4207 && TREE_CODE (cst2) == INTEGER_CST
4208 && INTEGRAL_TYPE_P (TREE_TYPE (name2))
4209 && live_on_edge (e, name2)
4210 && !has_single_use (name2))
4214 /* Build an expression for the range test. */
4216 if (TREE_TYPE (name) != TREE_TYPE (name2))
4217 tmp = build1 (NOP_EXPR, TREE_TYPE (name), tmp);
4218 if (cst2 != NULL_TREE)
4219 tmp = build2 (PLUS_EXPR, TREE_TYPE (name), tmp, cst2);
4223 fprintf (dump_file, "Adding assert for ");
4224 print_generic_expr (dump_file, name2, 0);
4225 fprintf (dump_file, " from ");
4226 print_generic_expr (dump_file, tmp, 0);
4227 fprintf (dump_file, "\n");
4230 register_new_assert_for (name2, tmp, comp_code, val, NULL, e, bsi);
4239 /* OP is an operand of a truth value expression which is known to have
4240 a particular value. Register any asserts for OP and for any
4241 operands in OP's defining statement.
4243 If CODE is EQ_EXPR, then we want to register OP is zero (false),
4244 if CODE is NE_EXPR, then we want to register OP is nonzero (true). */
4247 register_edge_assert_for_1 (tree op, enum tree_code code,
4248 edge e, gimple_stmt_iterator bsi)
4250 bool retval = false;
4253 enum tree_code rhs_code;
4255 /* We only care about SSA_NAMEs. */
4256 if (TREE_CODE (op) != SSA_NAME)
4259 /* We know that OP will have a zero or nonzero value. If OP is used
4260 more than once go ahead and register an assert for OP.
4262 The FOUND_IN_SUBGRAPH support is not helpful in this situation as
4263 it will always be set for OP (because OP is used in a COND_EXPR in
4265 if (!has_single_use (op))
4267 val = build_int_cst (TREE_TYPE (op), 0);
4268 register_new_assert_for (op, op, code, val, NULL, e, bsi);
4272 /* Now look at how OP is set. If it's set from a comparison,
4273 a truth operation or some bit operations, then we may be able
4274 to register information about the operands of that assignment. */
4275 op_def = SSA_NAME_DEF_STMT (op);
4276 if (gimple_code (op_def) != GIMPLE_ASSIGN)
4279 rhs_code = gimple_assign_rhs_code (op_def);
4281 if (TREE_CODE_CLASS (rhs_code) == tcc_comparison)
4283 bool invert = (code == EQ_EXPR ? true : false);
4284 tree op0 = gimple_assign_rhs1 (op_def);
4285 tree op1 = gimple_assign_rhs2 (op_def);
4287 if (TREE_CODE (op0) == SSA_NAME)
4288 retval |= register_edge_assert_for_2 (op0, e, bsi, rhs_code, op0, op1,
4290 if (TREE_CODE (op1) == SSA_NAME)
4291 retval |= register_edge_assert_for_2 (op1, e, bsi, rhs_code, op0, op1,
4294 else if ((code == NE_EXPR
4295 && (gimple_assign_rhs_code (op_def) == TRUTH_AND_EXPR
4296 || gimple_assign_rhs_code (op_def) == BIT_AND_EXPR))
4298 && (gimple_assign_rhs_code (op_def) == TRUTH_OR_EXPR
4299 || gimple_assign_rhs_code (op_def) == BIT_IOR_EXPR)))
4301 /* Recurse on each operand. */
4302 retval |= register_edge_assert_for_1 (gimple_assign_rhs1 (op_def),
4304 retval |= register_edge_assert_for_1 (gimple_assign_rhs2 (op_def),
4307 else if (gimple_assign_rhs_code (op_def) == TRUTH_NOT_EXPR)
4309 /* Recurse, flipping CODE. */
4310 code = invert_tree_comparison (code, false);
4311 retval |= register_edge_assert_for_1 (gimple_assign_rhs1 (op_def),
4314 else if (gimple_assign_rhs_code (op_def) == SSA_NAME)
4316 /* Recurse through the copy. */
4317 retval |= register_edge_assert_for_1 (gimple_assign_rhs1 (op_def),
4320 else if (CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (op_def)))
4322 /* Recurse through the type conversion. */
4323 retval |= register_edge_assert_for_1 (gimple_assign_rhs1 (op_def),
4330 /* Try to register an edge assertion for SSA name NAME on edge E for
4331 the condition COND contributing to the conditional jump pointed to by SI.
4332 Return true if an assertion for NAME could be registered. */
4335 register_edge_assert_for (tree name, edge e, gimple_stmt_iterator si,
4336 enum tree_code cond_code, tree cond_op0,
4340 enum tree_code comp_code;
4341 bool retval = false;
4342 bool is_else_edge = (e->flags & EDGE_FALSE_VALUE) != 0;
4344 /* Do not attempt to infer anything in names that flow through
4346 if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (name))
4349 if (!extract_code_and_val_from_cond_with_ops (name, cond_code,
4355 /* Register ASSERT_EXPRs for name. */
4356 retval |= register_edge_assert_for_2 (name, e, si, cond_code, cond_op0,
4357 cond_op1, is_else_edge);
4360 /* If COND is effectively an equality test of an SSA_NAME against
4361 the value zero or one, then we may be able to assert values
4362 for SSA_NAMEs which flow into COND. */
4364 /* In the case of NAME == 1 or NAME != 0, for TRUTH_AND_EXPR defining
4365 statement of NAME we can assert both operands of the TRUTH_AND_EXPR
4366 have nonzero value. */
4367 if (((comp_code == EQ_EXPR && integer_onep (val))
4368 || (comp_code == NE_EXPR && integer_zerop (val))))
4370 gimple def_stmt = SSA_NAME_DEF_STMT (name);
4372 if (is_gimple_assign (def_stmt)
4373 && (gimple_assign_rhs_code (def_stmt) == TRUTH_AND_EXPR
4374 || gimple_assign_rhs_code (def_stmt) == BIT_AND_EXPR))
4376 tree op0 = gimple_assign_rhs1 (def_stmt);
4377 tree op1 = gimple_assign_rhs2 (def_stmt);
4378 retval |= register_edge_assert_for_1 (op0, NE_EXPR, e, si);
4379 retval |= register_edge_assert_for_1 (op1, NE_EXPR, e, si);
4383 /* In the case of NAME == 0 or NAME != 1, for TRUTH_OR_EXPR defining
4384 statement of NAME we can assert both operands of the TRUTH_OR_EXPR
4386 if (((comp_code == EQ_EXPR && integer_zerop (val))
4387 || (comp_code == NE_EXPR && integer_onep (val))))
4389 gimple def_stmt = SSA_NAME_DEF_STMT (name);
4391 if (is_gimple_assign (def_stmt)
4392 && (gimple_assign_rhs_code (def_stmt) == TRUTH_OR_EXPR
4393 /* For BIT_IOR_EXPR only if NAME == 0 both operands have
4394 necessarily zero value. */
4395 || (comp_code == EQ_EXPR
4396 && (gimple_assign_rhs_code (def_stmt) == BIT_IOR_EXPR))))
4398 tree op0 = gimple_assign_rhs1 (def_stmt);
4399 tree op1 = gimple_assign_rhs2 (def_stmt);
4400 retval |= register_edge_assert_for_1 (op0, EQ_EXPR, e, si);
4401 retval |= register_edge_assert_for_1 (op1, EQ_EXPR, e, si);
4409 /* Determine whether the outgoing edges of BB should receive an
4410 ASSERT_EXPR for each of the operands of BB's LAST statement.
4411 The last statement of BB must be a COND_EXPR.
4413 If any of the sub-graphs rooted at BB have an interesting use of
4414 the predicate operands, an assert location node is added to the
4415 list of assertions for the corresponding operands. */
4418 find_conditional_asserts (basic_block bb, gimple last)
4421 gimple_stmt_iterator bsi;
4427 need_assert = false;
4428 bsi = gsi_for_stmt (last);
4430 /* Look for uses of the operands in each of the sub-graphs
4431 rooted at BB. We need to check each of the outgoing edges
4432 separately, so that we know what kind of ASSERT_EXPR to
4434 FOR_EACH_EDGE (e, ei, bb->succs)
4439 /* Register the necessary assertions for each operand in the
4440 conditional predicate. */
4441 FOR_EACH_SSA_TREE_OPERAND (op, last, iter, SSA_OP_USE)
4443 need_assert |= register_edge_assert_for (op, e, bsi,
4444 gimple_cond_code (last),
4445 gimple_cond_lhs (last),
4446 gimple_cond_rhs (last));
4453 /* Compare two case labels sorting first by the destination label uid
4454 and then by the case value. */
4457 compare_case_labels (const void *p1, const void *p2)
4459 const_tree const case1 = *(const_tree const*)p1;
4460 const_tree const case2 = *(const_tree const*)p2;
4461 unsigned int uid1 = DECL_UID (CASE_LABEL (case1));
4462 unsigned int uid2 = DECL_UID (CASE_LABEL (case2));
4466 else if (uid1 == uid2)
4468 /* Make sure the default label is first in a group. */
4469 if (!CASE_LOW (case1))
4471 else if (!CASE_LOW (case2))
4474 return tree_int_cst_compare (CASE_LOW (case1), CASE_LOW (case2));
4480 /* Determine whether the outgoing edges of BB should receive an
4481 ASSERT_EXPR for each of the operands of BB's LAST statement.
4482 The last statement of BB must be a SWITCH_EXPR.
4484 If any of the sub-graphs rooted at BB have an interesting use of
4485 the predicate operands, an assert location node is added to the
4486 list of assertions for the corresponding operands. */
4489 find_switch_asserts (basic_block bb, gimple last)
4492 gimple_stmt_iterator bsi;
4496 size_t n = gimple_switch_num_labels(last);
4497 #if GCC_VERSION >= 4000
4500 /* Work around GCC 3.4 bug (PR 37086). */
4501 volatile unsigned int idx;
4504 need_assert = false;
4505 bsi = gsi_for_stmt (last);
4506 op = gimple_switch_index (last);
4507 if (TREE_CODE (op) != SSA_NAME)
4510 /* Build a vector of case labels sorted by destination label. */
4511 vec2 = make_tree_vec (n);
4512 for (idx = 0; idx < n; ++idx)
4513 TREE_VEC_ELT (vec2, idx) = gimple_switch_label (last, idx);
4514 qsort (&TREE_VEC_ELT (vec2, 0), n, sizeof (tree), compare_case_labels);
4516 for (idx = 0; idx < n; ++idx)
4519 tree cl = TREE_VEC_ELT (vec2, idx);
4521 min = CASE_LOW (cl);
4522 max = CASE_HIGH (cl);
4524 /* If there are multiple case labels with the same destination
4525 we need to combine them to a single value range for the edge. */
4527 && CASE_LABEL (cl) == CASE_LABEL (TREE_VEC_ELT (vec2, idx + 1)))
4529 /* Skip labels until the last of the group. */
4533 && CASE_LABEL (cl) == CASE_LABEL (TREE_VEC_ELT (vec2, idx)));
4536 /* Pick up the maximum of the case label range. */
4537 if (CASE_HIGH (TREE_VEC_ELT (vec2, idx)))
4538 max = CASE_HIGH (TREE_VEC_ELT (vec2, idx));
4540 max = CASE_LOW (TREE_VEC_ELT (vec2, idx));
4543 /* Nothing to do if the range includes the default label until we
4544 can register anti-ranges. */
4545 if (min == NULL_TREE)
4548 /* Find the edge to register the assert expr on. */
4549 e = find_edge (bb, label_to_block (CASE_LABEL (cl)));
4551 /* Register the necessary assertions for the operand in the
4553 need_assert |= register_edge_assert_for (op, e, bsi,
4554 max ? GE_EXPR : EQ_EXPR,
4556 fold_convert (TREE_TYPE (op),
4560 need_assert |= register_edge_assert_for (op, e, bsi, LE_EXPR,
4562 fold_convert (TREE_TYPE (op),
4571 /* Traverse all the statements in block BB looking for statements that
4572 may generate useful assertions for the SSA names in their operand.
4573 If a statement produces a useful assertion A for name N_i, then the
4574 list of assertions already generated for N_i is scanned to
4575 determine if A is actually needed.
4577 If N_i already had the assertion A at a location dominating the
4578 current location, then nothing needs to be done. Otherwise, the
4579 new location for A is recorded instead.
4581 1- For every statement S in BB, all the variables used by S are
4582 added to bitmap FOUND_IN_SUBGRAPH.
4584 2- If statement S uses an operand N in a way that exposes a known
4585 value range for N, then if N was not already generated by an
4586 ASSERT_EXPR, create a new assert location for N. For instance,
4587 if N is a pointer and the statement dereferences it, we can
4588 assume that N is not NULL.
4590 3- COND_EXPRs are a special case of #2. We can derive range
4591 information from the predicate but need to insert different
4592 ASSERT_EXPRs for each of the sub-graphs rooted at the
4593 conditional block. If the last statement of BB is a conditional
4594 expression of the form 'X op Y', then
4596 a) Remove X and Y from the set FOUND_IN_SUBGRAPH.
4598 b) If the conditional is the only entry point to the sub-graph
4599 corresponding to the THEN_CLAUSE, recurse into it. On
4600 return, if X and/or Y are marked in FOUND_IN_SUBGRAPH, then
4601 an ASSERT_EXPR is added for the corresponding variable.
4603 c) Repeat step (b) on the ELSE_CLAUSE.
4605 d) Mark X and Y in FOUND_IN_SUBGRAPH.
4614 In this case, an assertion on the THEN clause is useful to
4615 determine that 'a' is always 9 on that edge. However, an assertion
4616 on the ELSE clause would be unnecessary.
4618 4- If BB does not end in a conditional expression, then we recurse
4619 into BB's dominator children.
4621 At the end of the recursive traversal, every SSA name will have a
4622 list of locations where ASSERT_EXPRs should be added. When a new
4623 location for name N is found, it is registered by calling
4624 register_new_assert_for. That function keeps track of all the
4625 registered assertions to prevent adding unnecessary assertions.
4626 For instance, if a pointer P_4 is dereferenced more than once in a
4627 dominator tree, only the location dominating all the dereference of
4628 P_4 will receive an ASSERT_EXPR.
4630 If this function returns true, then it means that there are names
4631 for which we need to generate ASSERT_EXPRs. Those assertions are
4632 inserted by process_assert_insertions. */
4635 find_assert_locations_1 (basic_block bb, sbitmap live)
4637 gimple_stmt_iterator si;
4642 need_assert = false;
4643 last = last_stmt (bb);
4645 /* If BB's last statement is a conditional statement involving integer
4646 operands, determine if we need to add ASSERT_EXPRs. */
4648 && gimple_code (last) == GIMPLE_COND
4649 && !fp_predicate (last)
4650 && !ZERO_SSA_OPERANDS (last, SSA_OP_USE))
4651 need_assert |= find_conditional_asserts (bb, last);
4653 /* If BB's last statement is a switch statement involving integer
4654 operands, determine if we need to add ASSERT_EXPRs. */
4656 && gimple_code (last) == GIMPLE_SWITCH
4657 && !ZERO_SSA_OPERANDS (last, SSA_OP_USE))
4658 need_assert |= find_switch_asserts (bb, last);
4660 /* Traverse all the statements in BB marking used names and looking
4661 for statements that may infer assertions for their used operands. */
4662 for (si = gsi_start_bb (bb); !gsi_end_p (si); gsi_next (&si))
4668 stmt = gsi_stmt (si);
4670 if (is_gimple_debug (stmt))
4673 /* See if we can derive an assertion for any of STMT's operands. */
4674 FOR_EACH_SSA_TREE_OPERAND (op, stmt, i, SSA_OP_USE)
4677 enum tree_code comp_code;
4679 /* Mark OP in our live bitmap. */
4680 SET_BIT (live, SSA_NAME_VERSION (op));
4682 /* If OP is used in such a way that we can infer a value
4683 range for it, and we don't find a previous assertion for
4684 it, create a new assertion location node for OP. */
4685 if (infer_value_range (stmt, op, &comp_code, &value))
4687 /* If we are able to infer a nonzero value range for OP,
4688 then walk backwards through the use-def chain to see if OP
4689 was set via a typecast.
4691 If so, then we can also infer a nonzero value range
4692 for the operand of the NOP_EXPR. */
4693 if (comp_code == NE_EXPR && integer_zerop (value))
4696 gimple def_stmt = SSA_NAME_DEF_STMT (t);
4698 while (is_gimple_assign (def_stmt)
4699 && gimple_assign_rhs_code (def_stmt) == NOP_EXPR
4701 (gimple_assign_rhs1 (def_stmt)) == SSA_NAME
4703 (TREE_TYPE (gimple_assign_rhs1 (def_stmt))))
4705 t = gimple_assign_rhs1 (def_stmt);
4706 def_stmt = SSA_NAME_DEF_STMT (t);
4708 /* Note we want to register the assert for the
4709 operand of the NOP_EXPR after SI, not after the
4711 if (! has_single_use (t))
4713 register_new_assert_for (t, t, comp_code, value,
4720 /* If OP is used only once, namely in this STMT, don't
4721 bother creating an ASSERT_EXPR for it. Such an
4722 ASSERT_EXPR would do nothing but increase compile time. */
4723 if (!has_single_use (op))
4725 register_new_assert_for (op, op, comp_code, value,
4733 /* Traverse all PHI nodes in BB marking used operands. */
4734 for (si = gsi_start_phis (bb); !gsi_end_p(si); gsi_next (&si))
4736 use_operand_p arg_p;
4738 phi = gsi_stmt (si);
4740 FOR_EACH_PHI_ARG (arg_p, phi, i, SSA_OP_USE)
4742 tree arg = USE_FROM_PTR (arg_p);
4743 if (TREE_CODE (arg) == SSA_NAME)
4744 SET_BIT (live, SSA_NAME_VERSION (arg));
4751 /* Do an RPO walk over the function computing SSA name liveness
4752 on-the-fly and deciding on assert expressions to insert.
4753 Returns true if there are assert expressions to be inserted. */
4756 find_assert_locations (void)
4758 int *rpo = XCNEWVEC (int, last_basic_block + NUM_FIXED_BLOCKS);
4759 int *bb_rpo = XCNEWVEC (int, last_basic_block + NUM_FIXED_BLOCKS);
4760 int *last_rpo = XCNEWVEC (int, last_basic_block + NUM_FIXED_BLOCKS);
4764 live = XCNEWVEC (sbitmap, last_basic_block + NUM_FIXED_BLOCKS);
4765 rpo_cnt = pre_and_rev_post_order_compute (NULL, rpo, false);
4766 for (i = 0; i < rpo_cnt; ++i)
4769 need_asserts = false;
4770 for (i = rpo_cnt-1; i >= 0; --i)
4772 basic_block bb = BASIC_BLOCK (rpo[i]);
4778 live[rpo[i]] = sbitmap_alloc (num_ssa_names);
4779 sbitmap_zero (live[rpo[i]]);
4782 /* Process BB and update the live information with uses in
4784 need_asserts |= find_assert_locations_1 (bb, live[rpo[i]]);
4786 /* Merge liveness into the predecessor blocks and free it. */
4787 if (!sbitmap_empty_p (live[rpo[i]]))
4790 FOR_EACH_EDGE (e, ei, bb->preds)
4792 int pred = e->src->index;
4793 if (e->flags & EDGE_DFS_BACK)
4798 live[pred] = sbitmap_alloc (num_ssa_names);
4799 sbitmap_zero (live[pred]);
4801 sbitmap_a_or_b (live[pred], live[pred], live[rpo[i]]);
4803 if (bb_rpo[pred] < pred_rpo)
4804 pred_rpo = bb_rpo[pred];
4807 /* Record the RPO number of the last visited block that needs
4808 live information from this block. */
4809 last_rpo[rpo[i]] = pred_rpo;
4813 sbitmap_free (live[rpo[i]]);
4814 live[rpo[i]] = NULL;
4817 /* We can free all successors live bitmaps if all their
4818 predecessors have been visited already. */
4819 FOR_EACH_EDGE (e, ei, bb->succs)
4820 if (last_rpo[e->dest->index] == i
4821 && live[e->dest->index])
4823 sbitmap_free (live[e->dest->index]);
4824 live[e->dest->index] = NULL;
4829 XDELETEVEC (bb_rpo);
4830 XDELETEVEC (last_rpo);
4831 for (i = 0; i < last_basic_block + NUM_FIXED_BLOCKS; ++i)
4833 sbitmap_free (live[i]);
4836 return need_asserts;
4839 /* Create an ASSERT_EXPR for NAME and insert it in the location
4840 indicated by LOC. Return true if we made any edge insertions. */
4843 process_assert_insertions_for (tree name, assert_locus_t loc)
4845 /* Build the comparison expression NAME_i COMP_CODE VAL. */
4852 /* If we have X <=> X do not insert an assert expr for that. */
4853 if (loc->expr == loc->val)
4856 cond = build2 (loc->comp_code, boolean_type_node, loc->expr, loc->val);
4857 assert_stmt = build_assert_expr_for (cond, name);
4860 /* We have been asked to insert the assertion on an edge. This
4861 is used only by COND_EXPR and SWITCH_EXPR assertions. */
4862 #if defined ENABLE_CHECKING
4863 gcc_assert (gimple_code (gsi_stmt (loc->si)) == GIMPLE_COND
4864 || gimple_code (gsi_stmt (loc->si)) == GIMPLE_SWITCH);
4867 gsi_insert_on_edge (loc->e, assert_stmt);
4871 /* Otherwise, we can insert right after LOC->SI iff the
4872 statement must not be the last statement in the block. */
4873 stmt = gsi_stmt (loc->si);
4874 if (!stmt_ends_bb_p (stmt))
4876 gsi_insert_after (&loc->si, assert_stmt, GSI_SAME_STMT);
4880 /* If STMT must be the last statement in BB, we can only insert new
4881 assertions on the non-abnormal edge out of BB. Note that since
4882 STMT is not control flow, there may only be one non-abnormal edge
4884 FOR_EACH_EDGE (e, ei, loc->bb->succs)
4885 if (!(e->flags & EDGE_ABNORMAL))
4887 gsi_insert_on_edge (e, assert_stmt);
4895 /* Process all the insertions registered for every name N_i registered
4896 in NEED_ASSERT_FOR. The list of assertions to be inserted are
4897 found in ASSERTS_FOR[i]. */
4900 process_assert_insertions (void)
4904 bool update_edges_p = false;
4905 int num_asserts = 0;
4907 if (dump_file && (dump_flags & TDF_DETAILS))
4908 dump_all_asserts (dump_file);
4910 EXECUTE_IF_SET_IN_BITMAP (need_assert_for, 0, i, bi)
4912 assert_locus_t loc = asserts_for[i];
4917 assert_locus_t next = loc->next;
4918 update_edges_p |= process_assert_insertions_for (ssa_name (i), loc);
4926 gsi_commit_edge_inserts ();
4928 statistics_counter_event (cfun, "Number of ASSERT_EXPR expressions inserted",
4933 /* Traverse the flowgraph looking for conditional jumps to insert range
4934 expressions. These range expressions are meant to provide information
4935 to optimizations that need to reason in terms of value ranges. They
4936 will not be expanded into RTL. For instance, given:
4945 this pass will transform the code into:
4951 x = ASSERT_EXPR <x, x < y>
4956 y = ASSERT_EXPR <y, x <= y>
4960 The idea is that once copy and constant propagation have run, other
4961 optimizations will be able to determine what ranges of values can 'x'
4962 take in different paths of the code, simply by checking the reaching
4963 definition of 'x'. */
4966 insert_range_assertions (void)
4968 need_assert_for = BITMAP_ALLOC (NULL);
4969 asserts_for = XCNEWVEC (assert_locus_t, num_ssa_names);
4971 calculate_dominance_info (CDI_DOMINATORS);
4973 if (find_assert_locations ())
4975 process_assert_insertions ();
4976 update_ssa (TODO_update_ssa_no_phi);
4979 if (dump_file && (dump_flags & TDF_DETAILS))
4981 fprintf (dump_file, "\nSSA form after inserting ASSERT_EXPRs\n");
4982 dump_function_to_file (current_function_decl, dump_file, dump_flags);
4986 BITMAP_FREE (need_assert_for);
4989 /* Checks one ARRAY_REF in REF, located at LOCUS. Ignores flexible arrays
4990 and "struct" hacks. If VRP can determine that the
4991 array subscript is a constant, check if it is outside valid
4992 range. If the array subscript is a RANGE, warn if it is
4993 non-overlapping with valid range.
4994 IGNORE_OFF_BY_ONE is true if the ARRAY_REF is inside a ADDR_EXPR. */
4997 check_array_ref (location_t location, tree ref, bool ignore_off_by_one)
4999 value_range_t* vr = NULL;
5000 tree low_sub, up_sub;
5001 tree low_bound, up_bound, up_bound_p1;
5004 if (TREE_NO_WARNING (ref))
5007 low_sub = up_sub = TREE_OPERAND (ref, 1);
5008 up_bound = array_ref_up_bound (ref);
5010 /* Can not check flexible arrays. */
5012 || TREE_CODE (up_bound) != INTEGER_CST)
5015 /* Accesses to trailing arrays via pointers may access storage
5016 beyond the types array bounds. */
5017 base = get_base_address (ref);
5019 && INDIRECT_REF_P (base))
5021 tree cref, next = NULL_TREE;
5023 if (TREE_CODE (TREE_OPERAND (ref, 0)) != COMPONENT_REF)
5026 cref = TREE_OPERAND (ref, 0);
5027 if (TREE_CODE (TREE_TYPE (TREE_OPERAND (cref, 0))) == RECORD_TYPE)
5028 for (next = TREE_CHAIN (TREE_OPERAND (cref, 1));
5029 next && TREE_CODE (next) != FIELD_DECL;
5030 next = TREE_CHAIN (next))
5033 /* If this is the last field in a struct type or a field in a
5034 union type do not warn. */
5039 low_bound = array_ref_low_bound (ref);
5040 up_bound_p1 = int_const_binop (PLUS_EXPR, up_bound, integer_one_node, 0);
5042 if (TREE_CODE (low_sub) == SSA_NAME)
5044 vr = get_value_range (low_sub);
5045 if (vr->type == VR_RANGE || vr->type == VR_ANTI_RANGE)
5047 low_sub = vr->type == VR_RANGE ? vr->max : vr->min;
5048 up_sub = vr->type == VR_RANGE ? vr->min : vr->max;
5052 if (vr && vr->type == VR_ANTI_RANGE)
5054 if (TREE_CODE (up_sub) == INTEGER_CST
5055 && tree_int_cst_lt (up_bound, up_sub)
5056 && TREE_CODE (low_sub) == INTEGER_CST
5057 && tree_int_cst_lt (low_sub, low_bound))
5059 warning_at (location, OPT_Warray_bounds,
5060 "array subscript is outside array bounds");
5061 TREE_NO_WARNING (ref) = 1;
5064 else if (TREE_CODE (up_sub) == INTEGER_CST
5065 && (ignore_off_by_one
5066 ? (tree_int_cst_lt (up_bound, up_sub)
5067 && !tree_int_cst_equal (up_bound_p1, up_sub))
5068 : (tree_int_cst_lt (up_bound, up_sub)
5069 || tree_int_cst_equal (up_bound_p1, up_sub))))
5071 warning_at (location, OPT_Warray_bounds,
5072 "array subscript is above array bounds");
5073 TREE_NO_WARNING (ref) = 1;
5075 else if (TREE_CODE (low_sub) == INTEGER_CST
5076 && tree_int_cst_lt (low_sub, low_bound))
5078 warning_at (location, OPT_Warray_bounds,
5079 "array subscript is below array bounds");
5080 TREE_NO_WARNING (ref) = 1;
5084 /* Searches if the expr T, located at LOCATION computes
5085 address of an ARRAY_REF, and call check_array_ref on it. */
5088 search_for_addr_array (tree t, location_t location)
5090 while (TREE_CODE (t) == SSA_NAME)
5092 gimple g = SSA_NAME_DEF_STMT (t);
5094 if (gimple_code (g) != GIMPLE_ASSIGN)
5097 if (get_gimple_rhs_class (gimple_assign_rhs_code (g))
5098 != GIMPLE_SINGLE_RHS)
5101 t = gimple_assign_rhs1 (g);
5105 /* We are only interested in addresses of ARRAY_REF's. */
5106 if (TREE_CODE (t) != ADDR_EXPR)
5109 /* Check each ARRAY_REFs in the reference chain. */
5112 if (TREE_CODE (t) == ARRAY_REF)
5113 check_array_ref (location, t, true /*ignore_off_by_one*/);
5115 t = TREE_OPERAND (t, 0);
5117 while (handled_component_p (t));
5120 /* walk_tree() callback that checks if *TP is
5121 an ARRAY_REF inside an ADDR_EXPR (in which an array
5122 subscript one outside the valid range is allowed). Call
5123 check_array_ref for each ARRAY_REF found. The location is
5127 check_array_bounds (tree *tp, int *walk_subtree, void *data)
5130 struct walk_stmt_info *wi = (struct walk_stmt_info *) data;
5131 location_t location;
5133 if (EXPR_HAS_LOCATION (t))
5134 location = EXPR_LOCATION (t);
5137 location_t *locp = (location_t *) wi->info;
5141 *walk_subtree = TRUE;
5143 if (TREE_CODE (t) == ARRAY_REF)
5144 check_array_ref (location, t, false /*ignore_off_by_one*/);
5146 if (TREE_CODE (t) == INDIRECT_REF
5147 || (TREE_CODE (t) == RETURN_EXPR && TREE_OPERAND (t, 0)))
5148 search_for_addr_array (TREE_OPERAND (t, 0), location);
5150 if (TREE_CODE (t) == ADDR_EXPR)
5151 *walk_subtree = FALSE;
5156 /* Walk over all statements of all reachable BBs and call check_array_bounds
5160 check_all_array_refs (void)
5163 gimple_stmt_iterator si;
5169 bool executable = false;
5171 /* Skip blocks that were found to be unreachable. */
5172 FOR_EACH_EDGE (e, ei, bb->preds)
5173 executable |= !!(e->flags & EDGE_EXECUTABLE);
5177 for (si = gsi_start_bb (bb); !gsi_end_p (si); gsi_next (&si))
5179 gimple stmt = gsi_stmt (si);
5180 struct walk_stmt_info wi;
5181 if (!gimple_has_location (stmt))
5184 if (is_gimple_call (stmt))
5187 size_t n = gimple_call_num_args (stmt);
5188 for (i = 0; i < n; i++)
5190 tree arg = gimple_call_arg (stmt, i);
5191 search_for_addr_array (arg, gimple_location (stmt));
5196 memset (&wi, 0, sizeof (wi));
5197 wi.info = CONST_CAST (void *, (const void *)
5198 gimple_location_ptr (stmt));
5200 walk_gimple_op (gsi_stmt (si),
5208 /* Convert range assertion expressions into the implied copies and
5209 copy propagate away the copies. Doing the trivial copy propagation
5210 here avoids the need to run the full copy propagation pass after
5213 FIXME, this will eventually lead to copy propagation removing the
5214 names that had useful range information attached to them. For
5215 instance, if we had the assertion N_i = ASSERT_EXPR <N_j, N_j > 3>,
5216 then N_i will have the range [3, +INF].
5218 However, by converting the assertion into the implied copy
5219 operation N_i = N_j, we will then copy-propagate N_j into the uses
5220 of N_i and lose the range information. We may want to hold on to
5221 ASSERT_EXPRs a little while longer as the ranges could be used in
5222 things like jump threading.
5224 The problem with keeping ASSERT_EXPRs around is that passes after
5225 VRP need to handle them appropriately.
5227 Another approach would be to make the range information a first
5228 class property of the SSA_NAME so that it can be queried from
5229 any pass. This is made somewhat more complex by the need for
5230 multiple ranges to be associated with one SSA_NAME. */
5233 remove_range_assertions (void)
5236 gimple_stmt_iterator si;
5238 /* Note that the BSI iterator bump happens at the bottom of the
5239 loop and no bump is necessary if we're removing the statement
5240 referenced by the current BSI. */
5242 for (si = gsi_start_bb (bb); !gsi_end_p (si);)
5244 gimple stmt = gsi_stmt (si);
5247 if (is_gimple_assign (stmt)
5248 && gimple_assign_rhs_code (stmt) == ASSERT_EXPR)
5250 tree rhs = gimple_assign_rhs1 (stmt);
5252 tree cond = fold (ASSERT_EXPR_COND (rhs));
5253 use_operand_p use_p;
5254 imm_use_iterator iter;
5256 gcc_assert (cond != boolean_false_node);
5258 /* Propagate the RHS into every use of the LHS. */
5259 var = ASSERT_EXPR_VAR (rhs);
5260 FOR_EACH_IMM_USE_STMT (use_stmt, iter,
5261 gimple_assign_lhs (stmt))
5262 FOR_EACH_IMM_USE_ON_STMT (use_p, iter)
5264 SET_USE (use_p, var);
5265 gcc_assert (TREE_CODE (var) == SSA_NAME);
5268 /* And finally, remove the copy, it is not needed. */
5269 gsi_remove (&si, true);
5270 release_defs (stmt);
5278 /* Return true if STMT is interesting for VRP. */
5281 stmt_interesting_for_vrp (gimple stmt)
5283 if (gimple_code (stmt) == GIMPLE_PHI
5284 && is_gimple_reg (gimple_phi_result (stmt))
5285 && (INTEGRAL_TYPE_P (TREE_TYPE (gimple_phi_result (stmt)))
5286 || POINTER_TYPE_P (TREE_TYPE (gimple_phi_result (stmt)))))
5288 else if (is_gimple_assign (stmt) || is_gimple_call (stmt))
5290 tree lhs = gimple_get_lhs (stmt);
5292 /* In general, assignments with virtual operands are not useful
5293 for deriving ranges, with the obvious exception of calls to
5294 builtin functions. */
5295 if (lhs && TREE_CODE (lhs) == SSA_NAME
5296 && (INTEGRAL_TYPE_P (TREE_TYPE (lhs))
5297 || POINTER_TYPE_P (TREE_TYPE (lhs)))
5298 && ((is_gimple_call (stmt)
5299 && gimple_call_fndecl (stmt) != NULL_TREE
5300 && DECL_IS_BUILTIN (gimple_call_fndecl (stmt)))
5301 || !gimple_vuse (stmt)))
5304 else if (gimple_code (stmt) == GIMPLE_COND
5305 || gimple_code (stmt) == GIMPLE_SWITCH)
5312 /* Initialize local data structures for VRP. */
5315 vrp_initialize (void)
5319 vr_value = XCNEWVEC (value_range_t *, num_ssa_names);
5320 vr_phi_edge_counts = XCNEWVEC (int, num_ssa_names);
5324 gimple_stmt_iterator si;
5326 for (si = gsi_start_phis (bb); !gsi_end_p (si); gsi_next (&si))
5328 gimple phi = gsi_stmt (si);
5329 if (!stmt_interesting_for_vrp (phi))
5331 tree lhs = PHI_RESULT (phi);
5332 set_value_range_to_varying (get_value_range (lhs));
5333 prop_set_simulate_again (phi, false);
5336 prop_set_simulate_again (phi, true);
5339 for (si = gsi_start_bb (bb); !gsi_end_p (si); gsi_next (&si))
5341 gimple stmt = gsi_stmt (si);
5343 /* If the statement is a control insn, then we do not
5344 want to avoid simulating the statement once. Failure
5345 to do so means that those edges will never get added. */
5346 if (stmt_ends_bb_p (stmt))
5347 prop_set_simulate_again (stmt, true);
5348 else if (!stmt_interesting_for_vrp (stmt))
5352 FOR_EACH_SSA_TREE_OPERAND (def, stmt, i, SSA_OP_DEF)
5353 set_value_range_to_varying (get_value_range (def));
5354 prop_set_simulate_again (stmt, false);
5357 prop_set_simulate_again (stmt, true);
5363 /* Visit assignment STMT. If it produces an interesting range, record
5364 the SSA name in *OUTPUT_P. */
5366 static enum ssa_prop_result
5367 vrp_visit_assignment_or_call (gimple stmt, tree *output_p)
5371 enum gimple_code code = gimple_code (stmt);
5372 lhs = gimple_get_lhs (stmt);
5374 /* We only keep track of ranges in integral and pointer types. */
5375 if (TREE_CODE (lhs) == SSA_NAME
5376 && ((INTEGRAL_TYPE_P (TREE_TYPE (lhs))
5377 /* It is valid to have NULL MIN/MAX values on a type. See
5378 build_range_type. */
5379 && TYPE_MIN_VALUE (TREE_TYPE (lhs))
5380 && TYPE_MAX_VALUE (TREE_TYPE (lhs)))
5381 || POINTER_TYPE_P (TREE_TYPE (lhs))))
5383 value_range_t new_vr = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
5385 if (code == GIMPLE_CALL)
5386 extract_range_basic (&new_vr, stmt);
5388 extract_range_from_assignment (&new_vr, stmt);
5390 if (update_value_range (lhs, &new_vr))
5394 if (dump_file && (dump_flags & TDF_DETAILS))
5396 fprintf (dump_file, "Found new range for ");
5397 print_generic_expr (dump_file, lhs, 0);
5398 fprintf (dump_file, ": ");
5399 dump_value_range (dump_file, &new_vr);
5400 fprintf (dump_file, "\n\n");
5403 if (new_vr.type == VR_VARYING)
5404 return SSA_PROP_VARYING;
5406 return SSA_PROP_INTERESTING;
5409 return SSA_PROP_NOT_INTERESTING;
5412 /* Every other statement produces no useful ranges. */
5413 FOR_EACH_SSA_TREE_OPERAND (def, stmt, iter, SSA_OP_DEF)
5414 set_value_range_to_varying (get_value_range (def));
5416 return SSA_PROP_VARYING;
5419 /* Helper that gets the value range of the SSA_NAME with version I
5420 or a symbolic range containing the SSA_NAME only if the value range
5421 is varying or undefined. */
5423 static inline value_range_t
5424 get_vr_for_comparison (int i)
5426 value_range_t vr = *(vr_value[i]);
5428 /* If name N_i does not have a valid range, use N_i as its own
5429 range. This allows us to compare against names that may
5430 have N_i in their ranges. */
5431 if (vr.type == VR_VARYING || vr.type == VR_UNDEFINED)
5434 vr.min = ssa_name (i);
5435 vr.max = ssa_name (i);
5441 /* Compare all the value ranges for names equivalent to VAR with VAL
5442 using comparison code COMP. Return the same value returned by
5443 compare_range_with_value, including the setting of
5444 *STRICT_OVERFLOW_P. */
5447 compare_name_with_value (enum tree_code comp, tree var, tree val,
5448 bool *strict_overflow_p)
5454 int used_strict_overflow;
5456 value_range_t equiv_vr;
5458 /* Get the set of equivalences for VAR. */
5459 e = get_value_range (var)->equiv;
5461 /* Start at -1. Set it to 0 if we do a comparison without relying
5462 on overflow, or 1 if all comparisons rely on overflow. */
5463 used_strict_overflow = -1;
5465 /* Compare vars' value range with val. */
5466 equiv_vr = get_vr_for_comparison (SSA_NAME_VERSION (var));
5468 retval = compare_range_with_value (comp, &equiv_vr, val, &sop);
5470 used_strict_overflow = sop ? 1 : 0;
5472 /* If the equiv set is empty we have done all work we need to do. */
5476 && used_strict_overflow > 0)
5477 *strict_overflow_p = true;
5481 EXECUTE_IF_SET_IN_BITMAP (e, 0, i, bi)
5483 equiv_vr = get_vr_for_comparison (i);
5485 t = compare_range_with_value (comp, &equiv_vr, val, &sop);
5488 /* If we get different answers from different members
5489 of the equivalence set this check must be in a dead
5490 code region. Folding it to a trap representation
5491 would be correct here. For now just return don't-know. */
5501 used_strict_overflow = 0;
5502 else if (used_strict_overflow < 0)
5503 used_strict_overflow = 1;
5508 && used_strict_overflow > 0)
5509 *strict_overflow_p = true;
5515 /* Given a comparison code COMP and names N1 and N2, compare all the
5516 ranges equivalent to N1 against all the ranges equivalent to N2
5517 to determine the value of N1 COMP N2. Return the same value
5518 returned by compare_ranges. Set *STRICT_OVERFLOW_P to indicate
5519 whether we relied on an overflow infinity in the comparison. */
5523 compare_names (enum tree_code comp, tree n1, tree n2,
5524 bool *strict_overflow_p)
5528 bitmap_iterator bi1, bi2;
5530 int used_strict_overflow;
5531 static bitmap_obstack *s_obstack = NULL;
5532 static bitmap s_e1 = NULL, s_e2 = NULL;
5534 /* Compare the ranges of every name equivalent to N1 against the
5535 ranges of every name equivalent to N2. */
5536 e1 = get_value_range (n1)->equiv;
5537 e2 = get_value_range (n2)->equiv;
5539 /* Use the fake bitmaps if e1 or e2 are not available. */
5540 if (s_obstack == NULL)
5542 s_obstack = XNEW (bitmap_obstack);
5543 bitmap_obstack_initialize (s_obstack);
5544 s_e1 = BITMAP_ALLOC (s_obstack);
5545 s_e2 = BITMAP_ALLOC (s_obstack);
5552 /* Add N1 and N2 to their own set of equivalences to avoid
5553 duplicating the body of the loop just to check N1 and N2
5555 bitmap_set_bit (e1, SSA_NAME_VERSION (n1));
5556 bitmap_set_bit (e2, SSA_NAME_VERSION (n2));
5558 /* If the equivalence sets have a common intersection, then the two
5559 names can be compared without checking their ranges. */
5560 if (bitmap_intersect_p (e1, e2))
5562 bitmap_clear_bit (e1, SSA_NAME_VERSION (n1));
5563 bitmap_clear_bit (e2, SSA_NAME_VERSION (n2));
5565 return (comp == EQ_EXPR || comp == GE_EXPR || comp == LE_EXPR)
5567 : boolean_false_node;
5570 /* Start at -1. Set it to 0 if we do a comparison without relying
5571 on overflow, or 1 if all comparisons rely on overflow. */
5572 used_strict_overflow = -1;
5574 /* Otherwise, compare all the equivalent ranges. First, add N1 and
5575 N2 to their own set of equivalences to avoid duplicating the body
5576 of the loop just to check N1 and N2 ranges. */
5577 EXECUTE_IF_SET_IN_BITMAP (e1, 0, i1, bi1)
5579 value_range_t vr1 = get_vr_for_comparison (i1);
5581 t = retval = NULL_TREE;
5582 EXECUTE_IF_SET_IN_BITMAP (e2, 0, i2, bi2)
5586 value_range_t vr2 = get_vr_for_comparison (i2);
5588 t = compare_ranges (comp, &vr1, &vr2, &sop);
5591 /* If we get different answers from different members
5592 of the equivalence set this check must be in a dead
5593 code region. Folding it to a trap representation
5594 would be correct here. For now just return don't-know. */
5598 bitmap_clear_bit (e1, SSA_NAME_VERSION (n1));
5599 bitmap_clear_bit (e2, SSA_NAME_VERSION (n2));
5605 used_strict_overflow = 0;
5606 else if (used_strict_overflow < 0)
5607 used_strict_overflow = 1;
5613 bitmap_clear_bit (e1, SSA_NAME_VERSION (n1));
5614 bitmap_clear_bit (e2, SSA_NAME_VERSION (n2));
5615 if (used_strict_overflow > 0)
5616 *strict_overflow_p = true;
5621 /* None of the equivalent ranges are useful in computing this
5623 bitmap_clear_bit (e1, SSA_NAME_VERSION (n1));
5624 bitmap_clear_bit (e2, SSA_NAME_VERSION (n2));
5628 /* Helper function for vrp_evaluate_conditional_warnv. */
5631 vrp_evaluate_conditional_warnv_with_ops_using_ranges (enum tree_code code,
5633 bool * strict_overflow_p)
5635 value_range_t *vr0, *vr1;
5637 vr0 = (TREE_CODE (op0) == SSA_NAME) ? get_value_range (op0) : NULL;
5638 vr1 = (TREE_CODE (op1) == SSA_NAME) ? get_value_range (op1) : NULL;
5641 return compare_ranges (code, vr0, vr1, strict_overflow_p);
5642 else if (vr0 && vr1 == NULL)
5643 return compare_range_with_value (code, vr0, op1, strict_overflow_p);
5644 else if (vr0 == NULL && vr1)
5645 return (compare_range_with_value
5646 (swap_tree_comparison (code), vr1, op0, strict_overflow_p));
5650 /* Helper function for vrp_evaluate_conditional_warnv. */
5653 vrp_evaluate_conditional_warnv_with_ops (enum tree_code code, tree op0,
5654 tree op1, bool use_equiv_p,
5655 bool *strict_overflow_p, bool *only_ranges)
5659 *only_ranges = true;
5661 /* We only deal with integral and pointer types. */
5662 if (!INTEGRAL_TYPE_P (TREE_TYPE (op0))
5663 && !POINTER_TYPE_P (TREE_TYPE (op0)))
5669 && (ret = vrp_evaluate_conditional_warnv_with_ops_using_ranges
5670 (code, op0, op1, strict_overflow_p)))
5672 *only_ranges = false;
5673 if (TREE_CODE (op0) == SSA_NAME && TREE_CODE (op1) == SSA_NAME)
5674 return compare_names (code, op0, op1, strict_overflow_p);
5675 else if (TREE_CODE (op0) == SSA_NAME)
5676 return compare_name_with_value (code, op0, op1, strict_overflow_p);
5677 else if (TREE_CODE (op1) == SSA_NAME)
5678 return (compare_name_with_value
5679 (swap_tree_comparison (code), op1, op0, strict_overflow_p));
5682 return vrp_evaluate_conditional_warnv_with_ops_using_ranges (code, op0, op1,
5687 /* Given (CODE OP0 OP1) within STMT, try to simplify it based on value range
5688 information. Return NULL if the conditional can not be evaluated.
5689 The ranges of all the names equivalent with the operands in COND
5690 will be used when trying to compute the value. If the result is
5691 based on undefined signed overflow, issue a warning if
5695 vrp_evaluate_conditional (enum tree_code code, tree op0, tree op1, gimple stmt)
5701 /* Some passes and foldings leak constants with overflow flag set
5702 into the IL. Avoid doing wrong things with these and bail out. */
5703 if ((TREE_CODE (op0) == INTEGER_CST
5704 && TREE_OVERFLOW (op0))
5705 || (TREE_CODE (op1) == INTEGER_CST
5706 && TREE_OVERFLOW (op1)))
5710 ret = vrp_evaluate_conditional_warnv_with_ops (code, op0, op1, true, &sop,
5715 enum warn_strict_overflow_code wc;
5716 const char* warnmsg;
5718 if (is_gimple_min_invariant (ret))
5720 wc = WARN_STRICT_OVERFLOW_CONDITIONAL;
5721 warnmsg = G_("assuming signed overflow does not occur when "
5722 "simplifying conditional to constant");
5726 wc = WARN_STRICT_OVERFLOW_COMPARISON;
5727 warnmsg = G_("assuming signed overflow does not occur when "
5728 "simplifying conditional");
5731 if (issue_strict_overflow_warning (wc))
5733 location_t location;
5735 if (!gimple_has_location (stmt))
5736 location = input_location;
5738 location = gimple_location (stmt);
5739 warning_at (location, OPT_Wstrict_overflow, "%s", warnmsg);
5743 if (warn_type_limits
5744 && ret && only_ranges
5745 && TREE_CODE_CLASS (code) == tcc_comparison
5746 && TREE_CODE (op0) == SSA_NAME)
5748 /* If the comparison is being folded and the operand on the LHS
5749 is being compared against a constant value that is outside of
5750 the natural range of OP0's type, then the predicate will
5751 always fold regardless of the value of OP0. If -Wtype-limits
5752 was specified, emit a warning. */
5753 tree type = TREE_TYPE (op0);
5754 value_range_t *vr0 = get_value_range (op0);
5756 if (vr0->type != VR_VARYING
5757 && INTEGRAL_TYPE_P (type)
5758 && vrp_val_is_min (vr0->min)
5759 && vrp_val_is_max (vr0->max)
5760 && is_gimple_min_invariant (op1))
5762 location_t location;
5764 if (!gimple_has_location (stmt))
5765 location = input_location;
5767 location = gimple_location (stmt);
5769 warning_at (location, OPT_Wtype_limits,
5771 ? G_("comparison always false "
5772 "due to limited range of data type")
5773 : G_("comparison always true "
5774 "due to limited range of data type"));
5782 /* Visit conditional statement STMT. If we can determine which edge
5783 will be taken out of STMT's basic block, record it in
5784 *TAKEN_EDGE_P and return SSA_PROP_INTERESTING. Otherwise, return
5785 SSA_PROP_VARYING. */
5787 static enum ssa_prop_result
5788 vrp_visit_cond_stmt (gimple stmt, edge *taken_edge_p)
5793 *taken_edge_p = NULL;
5795 if (dump_file && (dump_flags & TDF_DETAILS))
5800 fprintf (dump_file, "\nVisiting conditional with predicate: ");
5801 print_gimple_stmt (dump_file, stmt, 0, 0);
5802 fprintf (dump_file, "\nWith known ranges\n");
5804 FOR_EACH_SSA_TREE_OPERAND (use, stmt, i, SSA_OP_USE)
5806 fprintf (dump_file, "\t");
5807 print_generic_expr (dump_file, use, 0);
5808 fprintf (dump_file, ": ");
5809 dump_value_range (dump_file, vr_value[SSA_NAME_VERSION (use)]);
5812 fprintf (dump_file, "\n");
5815 /* Compute the value of the predicate COND by checking the known
5816 ranges of each of its operands.
5818 Note that we cannot evaluate all the equivalent ranges here
5819 because those ranges may not yet be final and with the current
5820 propagation strategy, we cannot determine when the value ranges
5821 of the names in the equivalence set have changed.
5823 For instance, given the following code fragment
5827 i_14 = ASSERT_EXPR <i_5, i_5 != 0>
5831 Assume that on the first visit to i_14, i_5 has the temporary
5832 range [8, 8] because the second argument to the PHI function is
5833 not yet executable. We derive the range ~[0, 0] for i_14 and the
5834 equivalence set { i_5 }. So, when we visit 'if (i_14 == 1)' for
5835 the first time, since i_14 is equivalent to the range [8, 8], we
5836 determine that the predicate is always false.
5838 On the next round of propagation, i_13 is determined to be
5839 VARYING, which causes i_5 to drop down to VARYING. So, another
5840 visit to i_14 is scheduled. In this second visit, we compute the
5841 exact same range and equivalence set for i_14, namely ~[0, 0] and
5842 { i_5 }. But we did not have the previous range for i_5
5843 registered, so vrp_visit_assignment thinks that the range for
5844 i_14 has not changed. Therefore, the predicate 'if (i_14 == 1)'
5845 is not visited again, which stops propagation from visiting
5846 statements in the THEN clause of that if().
5848 To properly fix this we would need to keep the previous range
5849 value for the names in the equivalence set. This way we would've
5850 discovered that from one visit to the other i_5 changed from
5851 range [8, 8] to VR_VARYING.
5853 However, fixing this apparent limitation may not be worth the
5854 additional checking. Testing on several code bases (GCC, DLV,
5855 MICO, TRAMP3D and SPEC2000) showed that doing this results in
5856 4 more predicates folded in SPEC. */
5859 val = vrp_evaluate_conditional_warnv_with_ops (gimple_cond_code (stmt),
5860 gimple_cond_lhs (stmt),
5861 gimple_cond_rhs (stmt),
5866 *taken_edge_p = find_taken_edge (gimple_bb (stmt), val);
5869 if (dump_file && (dump_flags & TDF_DETAILS))
5871 "\nIgnoring predicate evaluation because "
5872 "it assumes that signed overflow is undefined");
5877 if (dump_file && (dump_flags & TDF_DETAILS))
5879 fprintf (dump_file, "\nPredicate evaluates to: ");
5880 if (val == NULL_TREE)
5881 fprintf (dump_file, "DON'T KNOW\n");
5883 print_generic_stmt (dump_file, val, 0);
5886 return (*taken_edge_p) ? SSA_PROP_INTERESTING : SSA_PROP_VARYING;
5889 /* Searches the case label vector VEC for the index *IDX of the CASE_LABEL
5890 that includes the value VAL. The search is restricted to the range
5891 [START_IDX, n - 1] where n is the size of VEC.
5893 If there is a CASE_LABEL for VAL, its index is placed in IDX and true is
5896 If there is no CASE_LABEL for VAL and there is one that is larger than VAL,
5897 it is placed in IDX and false is returned.
5899 If VAL is larger than any CASE_LABEL, n is placed on IDX and false is
5903 find_case_label_index (gimple stmt, size_t start_idx, tree val, size_t *idx)
5905 size_t n = gimple_switch_num_labels (stmt);
5908 /* Find case label for minimum of the value range or the next one.
5909 At each iteration we are searching in [low, high - 1]. */
5911 for (low = start_idx, high = n; high != low; )
5915 /* Note that i != high, so we never ask for n. */
5916 size_t i = (high + low) / 2;
5917 t = gimple_switch_label (stmt, i);
5919 /* Cache the result of comparing CASE_LOW and val. */
5920 cmp = tree_int_cst_compare (CASE_LOW (t), val);
5924 /* Ranges cannot be empty. */
5933 if (CASE_HIGH (t) != NULL
5934 && tree_int_cst_compare (CASE_HIGH (t), val) >= 0)
5946 /* Searches the case label vector VEC for the range of CASE_LABELs that is used
5947 for values between MIN and MAX. The first index is placed in MIN_IDX. The
5948 last index is placed in MAX_IDX. If the range of CASE_LABELs is empty
5949 then MAX_IDX < MIN_IDX.
5950 Returns true if the default label is not needed. */
5953 find_case_label_range (gimple stmt, tree min, tree max, size_t *min_idx,
5957 bool min_take_default = !find_case_label_index (stmt, 1, min, &i);
5958 bool max_take_default = !find_case_label_index (stmt, i, max, &j);
5962 && max_take_default)
5964 /* Only the default case label reached.
5965 Return an empty range. */
5972 bool take_default = min_take_default || max_take_default;
5976 if (max_take_default)
5979 /* If the case label range is continuous, we do not need
5980 the default case label. Verify that. */
5981 high = CASE_LOW (gimple_switch_label (stmt, i));
5982 if (CASE_HIGH (gimple_switch_label (stmt, i)))
5983 high = CASE_HIGH (gimple_switch_label (stmt, i));
5984 for (k = i + 1; k <= j; ++k)
5986 low = CASE_LOW (gimple_switch_label (stmt, k));
5987 if (!integer_onep (int_const_binop (MINUS_EXPR, low, high, 0)))
5989 take_default = true;
5993 if (CASE_HIGH (gimple_switch_label (stmt, k)))
5994 high = CASE_HIGH (gimple_switch_label (stmt, k));
5999 return !take_default;
6003 /* Visit switch statement STMT. If we can determine which edge
6004 will be taken out of STMT's basic block, record it in
6005 *TAKEN_EDGE_P and return SSA_PROP_INTERESTING. Otherwise, return
6006 SSA_PROP_VARYING. */
6008 static enum ssa_prop_result
6009 vrp_visit_switch_stmt (gimple stmt, edge *taken_edge_p)
6013 size_t i = 0, j = 0;
6016 *taken_edge_p = NULL;
6017 op = gimple_switch_index (stmt);
6018 if (TREE_CODE (op) != SSA_NAME)
6019 return SSA_PROP_VARYING;
6021 vr = get_value_range (op);
6022 if (dump_file && (dump_flags & TDF_DETAILS))
6024 fprintf (dump_file, "\nVisiting switch expression with operand ");
6025 print_generic_expr (dump_file, op, 0);
6026 fprintf (dump_file, " with known range ");
6027 dump_value_range (dump_file, vr);
6028 fprintf (dump_file, "\n");
6031 if (vr->type != VR_RANGE
6032 || symbolic_range_p (vr))
6033 return SSA_PROP_VARYING;
6035 /* Find the single edge that is taken from the switch expression. */
6036 take_default = !find_case_label_range (stmt, vr->min, vr->max, &i, &j);
6038 /* Check if the range spans no CASE_LABEL. If so, we only reach the default
6042 gcc_assert (take_default);
6043 val = gimple_switch_default_label (stmt);
6047 /* Check if labels with index i to j and maybe the default label
6048 are all reaching the same label. */
6050 val = gimple_switch_label (stmt, i);
6052 && CASE_LABEL (gimple_switch_default_label (stmt))
6053 != CASE_LABEL (val))
6055 if (dump_file && (dump_flags & TDF_DETAILS))
6056 fprintf (dump_file, " not a single destination for this "
6058 return SSA_PROP_VARYING;
6060 for (++i; i <= j; ++i)
6062 if (CASE_LABEL (gimple_switch_label (stmt, i)) != CASE_LABEL (val))
6064 if (dump_file && (dump_flags & TDF_DETAILS))
6065 fprintf (dump_file, " not a single destination for this "
6067 return SSA_PROP_VARYING;
6072 *taken_edge_p = find_edge (gimple_bb (stmt),
6073 label_to_block (CASE_LABEL (val)));
6075 if (dump_file && (dump_flags & TDF_DETAILS))
6077 fprintf (dump_file, " will take edge to ");
6078 print_generic_stmt (dump_file, CASE_LABEL (val), 0);
6081 return SSA_PROP_INTERESTING;
6085 /* Evaluate statement STMT. If the statement produces a useful range,
6086 return SSA_PROP_INTERESTING and record the SSA name with the
6087 interesting range into *OUTPUT_P.
6089 If STMT is a conditional branch and we can determine its truth
6090 value, the taken edge is recorded in *TAKEN_EDGE_P.
6092 If STMT produces a varying value, return SSA_PROP_VARYING. */
6094 static enum ssa_prop_result
6095 vrp_visit_stmt (gimple stmt, edge *taken_edge_p, tree *output_p)
6100 if (dump_file && (dump_flags & TDF_DETAILS))
6102 fprintf (dump_file, "\nVisiting statement:\n");
6103 print_gimple_stmt (dump_file, stmt, 0, dump_flags);
6104 fprintf (dump_file, "\n");
6107 if (!stmt_interesting_for_vrp (stmt))
6108 gcc_assert (stmt_ends_bb_p (stmt));
6109 else if (is_gimple_assign (stmt) || is_gimple_call (stmt))
6111 /* In general, assignments with virtual operands are not useful
6112 for deriving ranges, with the obvious exception of calls to
6113 builtin functions. */
6115 if ((is_gimple_call (stmt)
6116 && gimple_call_fndecl (stmt) != NULL_TREE
6117 && DECL_IS_BUILTIN (gimple_call_fndecl (stmt)))
6118 || !gimple_vuse (stmt))
6119 return vrp_visit_assignment_or_call (stmt, output_p);
6121 else if (gimple_code (stmt) == GIMPLE_COND)
6122 return vrp_visit_cond_stmt (stmt, taken_edge_p);
6123 else if (gimple_code (stmt) == GIMPLE_SWITCH)
6124 return vrp_visit_switch_stmt (stmt, taken_edge_p);
6126 /* All other statements produce nothing of interest for VRP, so mark
6127 their outputs varying and prevent further simulation. */
6128 FOR_EACH_SSA_TREE_OPERAND (def, stmt, iter, SSA_OP_DEF)
6129 set_value_range_to_varying (get_value_range (def));
6131 return SSA_PROP_VARYING;
6135 /* Meet operation for value ranges. Given two value ranges VR0 and
6136 VR1, store in VR0 a range that contains both VR0 and VR1. This
6137 may not be the smallest possible such range. */
6140 vrp_meet (value_range_t *vr0, value_range_t *vr1)
6142 if (vr0->type == VR_UNDEFINED)
6144 copy_value_range (vr0, vr1);
6148 if (vr1->type == VR_UNDEFINED)
6150 /* Nothing to do. VR0 already has the resulting range. */
6154 if (vr0->type == VR_VARYING)
6156 /* Nothing to do. VR0 already has the resulting range. */
6160 if (vr1->type == VR_VARYING)
6162 set_value_range_to_varying (vr0);
6166 if (vr0->type == VR_RANGE && vr1->type == VR_RANGE)
6171 /* Compute the convex hull of the ranges. The lower limit of
6172 the new range is the minimum of the two ranges. If they
6173 cannot be compared, then give up. */
6174 cmp = compare_values (vr0->min, vr1->min);
6175 if (cmp == 0 || cmp == 1)
6182 /* Similarly, the upper limit of the new range is the maximum
6183 of the two ranges. If they cannot be compared, then
6185 cmp = compare_values (vr0->max, vr1->max);
6186 if (cmp == 0 || cmp == -1)
6193 /* Check for useless ranges. */
6194 if (INTEGRAL_TYPE_P (TREE_TYPE (min))
6195 && ((vrp_val_is_min (min) || is_overflow_infinity (min))
6196 && (vrp_val_is_max (max) || is_overflow_infinity (max))))
6199 /* The resulting set of equivalences is the intersection of
6201 if (vr0->equiv && vr1->equiv && vr0->equiv != vr1->equiv)
6202 bitmap_and_into (vr0->equiv, vr1->equiv);
6203 else if (vr0->equiv && !vr1->equiv)
6204 bitmap_clear (vr0->equiv);
6206 set_value_range (vr0, vr0->type, min, max, vr0->equiv);
6208 else if (vr0->type == VR_ANTI_RANGE && vr1->type == VR_ANTI_RANGE)
6210 /* Two anti-ranges meet only if their complements intersect.
6211 Only handle the case of identical ranges. */
6212 if (compare_values (vr0->min, vr1->min) == 0
6213 && compare_values (vr0->max, vr1->max) == 0
6214 && compare_values (vr0->min, vr0->max) == 0)
6216 /* The resulting set of equivalences is the intersection of
6218 if (vr0->equiv && vr1->equiv && vr0->equiv != vr1->equiv)
6219 bitmap_and_into (vr0->equiv, vr1->equiv);
6220 else if (vr0->equiv && !vr1->equiv)
6221 bitmap_clear (vr0->equiv);
6226 else if (vr0->type == VR_ANTI_RANGE || vr1->type == VR_ANTI_RANGE)
6228 /* For a numeric range [VAL1, VAL2] and an anti-range ~[VAL3, VAL4],
6229 only handle the case where the ranges have an empty intersection.
6230 The result of the meet operation is the anti-range. */
6231 if (!symbolic_range_p (vr0)
6232 && !symbolic_range_p (vr1)
6233 && !value_ranges_intersect_p (vr0, vr1))
6235 /* Copy most of VR1 into VR0. Don't copy VR1's equivalence
6236 set. We need to compute the intersection of the two
6237 equivalence sets. */
6238 if (vr1->type == VR_ANTI_RANGE)
6239 set_value_range (vr0, vr1->type, vr1->min, vr1->max, vr0->equiv);
6241 /* The resulting set of equivalences is the intersection of
6243 if (vr0->equiv && vr1->equiv && vr0->equiv != vr1->equiv)
6244 bitmap_and_into (vr0->equiv, vr1->equiv);
6245 else if (vr0->equiv && !vr1->equiv)
6246 bitmap_clear (vr0->equiv);
6257 /* Failed to find an efficient meet. Before giving up and setting
6258 the result to VARYING, see if we can at least derive a useful
6259 anti-range. FIXME, all this nonsense about distinguishing
6260 anti-ranges from ranges is necessary because of the odd
6261 semantics of range_includes_zero_p and friends. */
6262 if (!symbolic_range_p (vr0)
6263 && ((vr0->type == VR_RANGE && !range_includes_zero_p (vr0))
6264 || (vr0->type == VR_ANTI_RANGE && range_includes_zero_p (vr0)))
6265 && !symbolic_range_p (vr1)
6266 && ((vr1->type == VR_RANGE && !range_includes_zero_p (vr1))
6267 || (vr1->type == VR_ANTI_RANGE && range_includes_zero_p (vr1))))
6269 set_value_range_to_nonnull (vr0, TREE_TYPE (vr0->min));
6271 /* Since this meet operation did not result from the meeting of
6272 two equivalent names, VR0 cannot have any equivalences. */
6274 bitmap_clear (vr0->equiv);
6277 set_value_range_to_varying (vr0);
6281 /* Visit all arguments for PHI node PHI that flow through executable
6282 edges. If a valid value range can be derived from all the incoming
6283 value ranges, set a new range for the LHS of PHI. */
6285 static enum ssa_prop_result
6286 vrp_visit_phi_node (gimple phi)
6289 tree lhs = PHI_RESULT (phi);
6290 value_range_t *lhs_vr = get_value_range (lhs);
6291 value_range_t vr_result = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
6292 int edges, old_edges;
6295 copy_value_range (&vr_result, lhs_vr);
6297 if (dump_file && (dump_flags & TDF_DETAILS))
6299 fprintf (dump_file, "\nVisiting PHI node: ");
6300 print_gimple_stmt (dump_file, phi, 0, dump_flags);
6304 for (i = 0; i < gimple_phi_num_args (phi); i++)
6306 edge e = gimple_phi_arg_edge (phi, i);
6308 if (dump_file && (dump_flags & TDF_DETAILS))
6311 "\n Argument #%d (%d -> %d %sexecutable)\n",
6312 (int) i, e->src->index, e->dest->index,
6313 (e->flags & EDGE_EXECUTABLE) ? "" : "not ");
6316 if (e->flags & EDGE_EXECUTABLE)
6318 tree arg = PHI_ARG_DEF (phi, i);
6319 value_range_t vr_arg;
6323 if (TREE_CODE (arg) == SSA_NAME)
6325 vr_arg = *(get_value_range (arg));
6329 if (is_overflow_infinity (arg))
6331 arg = copy_node (arg);
6332 TREE_OVERFLOW (arg) = 0;
6335 vr_arg.type = VR_RANGE;
6338 vr_arg.equiv = NULL;
6341 if (dump_file && (dump_flags & TDF_DETAILS))
6343 fprintf (dump_file, "\t");
6344 print_generic_expr (dump_file, arg, dump_flags);
6345 fprintf (dump_file, "\n\tValue: ");
6346 dump_value_range (dump_file, &vr_arg);
6347 fprintf (dump_file, "\n");
6350 vrp_meet (&vr_result, &vr_arg);
6352 if (vr_result.type == VR_VARYING)
6357 /* If this is a loop PHI node SCEV may known more about its
6360 && (l = loop_containing_stmt (phi))
6361 && l->header == gimple_bb (phi))
6362 adjust_range_with_scev (&vr_result, l, phi, lhs);
6364 if (vr_result.type == VR_VARYING)
6367 old_edges = vr_phi_edge_counts[SSA_NAME_VERSION (lhs)];
6368 vr_phi_edge_counts[SSA_NAME_VERSION (lhs)] = edges;
6370 /* To prevent infinite iterations in the algorithm, derive ranges
6371 when the new value is slightly bigger or smaller than the
6372 previous one. We don't do this if we have seen a new executable
6373 edge; this helps us avoid an overflow infinity for conditionals
6374 which are not in a loop. */
6375 if (lhs_vr->type == VR_RANGE && vr_result.type == VR_RANGE
6376 && edges <= old_edges)
6378 if (!POINTER_TYPE_P (TREE_TYPE (lhs)))
6380 int cmp_min = compare_values (lhs_vr->min, vr_result.min);
6381 int cmp_max = compare_values (lhs_vr->max, vr_result.max);
6383 /* If the new minimum is smaller or larger than the previous
6384 one, go all the way to -INF. In the first case, to avoid
6385 iterating millions of times to reach -INF, and in the
6386 other case to avoid infinite bouncing between different
6388 if (cmp_min > 0 || cmp_min < 0)
6390 /* If we will end up with a (-INF, +INF) range, set it to
6391 VARYING. Same if the previous max value was invalid for
6392 the type and we'd end up with vr_result.min > vr_result.max. */
6393 if (vrp_val_is_max (vr_result.max)
6394 || compare_values (TYPE_MIN_VALUE (TREE_TYPE (vr_result.min)),
6398 if (!needs_overflow_infinity (TREE_TYPE (vr_result.min))
6399 || !vrp_var_may_overflow (lhs, phi))
6400 vr_result.min = TYPE_MIN_VALUE (TREE_TYPE (vr_result.min));
6401 else if (supports_overflow_infinity (TREE_TYPE (vr_result.min)))
6403 negative_overflow_infinity (TREE_TYPE (vr_result.min));
6408 /* Similarly, if the new maximum is smaller or larger than
6409 the previous one, go all the way to +INF. */
6410 if (cmp_max < 0 || cmp_max > 0)
6412 /* If we will end up with a (-INF, +INF) range, set it to
6413 VARYING. Same if the previous min value was invalid for
6414 the type and we'd end up with vr_result.max < vr_result.min. */
6415 if (vrp_val_is_min (vr_result.min)
6416 || compare_values (TYPE_MAX_VALUE (TREE_TYPE (vr_result.max)),
6420 if (!needs_overflow_infinity (TREE_TYPE (vr_result.max))
6421 || !vrp_var_may_overflow (lhs, phi))
6422 vr_result.max = TYPE_MAX_VALUE (TREE_TYPE (vr_result.max));
6423 else if (supports_overflow_infinity (TREE_TYPE (vr_result.max)))
6425 positive_overflow_infinity (TREE_TYPE (vr_result.max));
6432 /* If the new range is different than the previous value, keep
6434 if (update_value_range (lhs, &vr_result))
6435 return SSA_PROP_INTERESTING;
6437 /* Nothing changed, don't add outgoing edges. */
6438 return SSA_PROP_NOT_INTERESTING;
6440 /* No match found. Set the LHS to VARYING. */
6442 set_value_range_to_varying (lhs_vr);
6443 return SSA_PROP_VARYING;
6446 /* Simplify boolean operations if the source is known
6447 to be already a boolean. */
6449 simplify_truth_ops_using_ranges (gimple_stmt_iterator *gsi, gimple stmt)
6451 enum tree_code rhs_code = gimple_assign_rhs_code (stmt);
6456 bool need_conversion;
6458 op0 = gimple_assign_rhs1 (stmt);
6459 if (TYPE_PRECISION (TREE_TYPE (op0)) != 1)
6461 if (TREE_CODE (op0) != SSA_NAME)
6463 vr = get_value_range (op0);
6465 val = compare_range_with_value (GE_EXPR, vr, integer_zero_node, &sop);
6466 if (!val || !integer_onep (val))
6469 val = compare_range_with_value (LE_EXPR, vr, integer_one_node, &sop);
6470 if (!val || !integer_onep (val))
6474 if (rhs_code == TRUTH_NOT_EXPR)
6477 op1 = build_int_cst (TREE_TYPE (op0), 1);
6481 op1 = gimple_assign_rhs2 (stmt);
6483 /* Reduce number of cases to handle. */
6484 if (is_gimple_min_invariant (op1))
6486 /* Exclude anything that should have been already folded. */
6487 if (rhs_code != EQ_EXPR
6488 && rhs_code != NE_EXPR
6489 && rhs_code != TRUTH_XOR_EXPR)
6492 if (!integer_zerop (op1)
6493 && !integer_onep (op1)
6494 && !integer_all_onesp (op1))
6497 /* Limit the number of cases we have to consider. */
6498 if (rhs_code == EQ_EXPR)
6501 op1 = fold_unary (TRUTH_NOT_EXPR, TREE_TYPE (op1), op1);
6506 /* Punt on A == B as there is no BIT_XNOR_EXPR. */
6507 if (rhs_code == EQ_EXPR)
6510 if (TYPE_PRECISION (TREE_TYPE (op1)) != 1)
6512 vr = get_value_range (op1);
6513 val = compare_range_with_value (GE_EXPR, vr, integer_zero_node, &sop);
6514 if (!val || !integer_onep (val))
6517 val = compare_range_with_value (LE_EXPR, vr, integer_one_node, &sop);
6518 if (!val || !integer_onep (val))
6524 if (sop && issue_strict_overflow_warning (WARN_STRICT_OVERFLOW_MISC))
6526 location_t location;
6528 if (!gimple_has_location (stmt))
6529 location = input_location;
6531 location = gimple_location (stmt);
6533 if (rhs_code == TRUTH_AND_EXPR || rhs_code == TRUTH_OR_EXPR)
6534 warning_at (location, OPT_Wstrict_overflow,
6535 _("assuming signed overflow does not occur when "
6536 "simplifying && or || to & or |"));
6538 warning_at (location, OPT_Wstrict_overflow,
6539 _("assuming signed overflow does not occur when "
6540 "simplifying ==, != or ! to identity or ^"));
6544 !useless_type_conversion_p (TREE_TYPE (gimple_assign_lhs (stmt)),
6547 /* Make sure to not sign-extend -1 as a boolean value. */
6549 && !TYPE_UNSIGNED (TREE_TYPE (op0))
6550 && TYPE_PRECISION (TREE_TYPE (op0)) == 1)
6555 case TRUTH_AND_EXPR:
6556 rhs_code = BIT_AND_EXPR;
6559 rhs_code = BIT_IOR_EXPR;
6561 case TRUTH_XOR_EXPR:
6563 if (integer_zerop (op1))
6565 gimple_assign_set_rhs_with_ops (gsi,
6566 need_conversion ? NOP_EXPR : SSA_NAME,
6568 update_stmt (gsi_stmt (*gsi));
6572 rhs_code = BIT_XOR_EXPR;
6578 if (need_conversion)
6581 gimple_assign_set_rhs_with_ops (gsi, rhs_code, op0, op1);
6582 update_stmt (gsi_stmt (*gsi));
6586 /* Simplify a division or modulo operator to a right shift or
6587 bitwise and if the first operand is unsigned or is greater
6588 than zero and the second operand is an exact power of two. */
6591 simplify_div_or_mod_using_ranges (gimple stmt)
6593 enum tree_code rhs_code = gimple_assign_rhs_code (stmt);
6595 tree op0 = gimple_assign_rhs1 (stmt);
6596 tree op1 = gimple_assign_rhs2 (stmt);
6597 value_range_t *vr = get_value_range (gimple_assign_rhs1 (stmt));
6599 if (TYPE_UNSIGNED (TREE_TYPE (op0)))
6601 val = integer_one_node;
6607 val = compare_range_with_value (GE_EXPR, vr, integer_zero_node, &sop);
6611 && integer_onep (val)
6612 && issue_strict_overflow_warning (WARN_STRICT_OVERFLOW_MISC))
6614 location_t location;
6616 if (!gimple_has_location (stmt))
6617 location = input_location;
6619 location = gimple_location (stmt);
6620 warning_at (location, OPT_Wstrict_overflow,
6621 "assuming signed overflow does not occur when "
6622 "simplifying %</%> or %<%%%> to %<>>%> or %<&%>");
6626 if (val && integer_onep (val))
6630 if (rhs_code == TRUNC_DIV_EXPR)
6632 t = build_int_cst (NULL_TREE, tree_log2 (op1));
6633 gimple_assign_set_rhs_code (stmt, RSHIFT_EXPR);
6634 gimple_assign_set_rhs1 (stmt, op0);
6635 gimple_assign_set_rhs2 (stmt, t);
6639 t = build_int_cst (TREE_TYPE (op1), 1);
6640 t = int_const_binop (MINUS_EXPR, op1, t, 0);
6641 t = fold_convert (TREE_TYPE (op0), t);
6643 gimple_assign_set_rhs_code (stmt, BIT_AND_EXPR);
6644 gimple_assign_set_rhs1 (stmt, op0);
6645 gimple_assign_set_rhs2 (stmt, t);
6655 /* If the operand to an ABS_EXPR is >= 0, then eliminate the
6656 ABS_EXPR. If the operand is <= 0, then simplify the
6657 ABS_EXPR into a NEGATE_EXPR. */
6660 simplify_abs_using_ranges (gimple stmt)
6663 tree op = gimple_assign_rhs1 (stmt);
6664 tree type = TREE_TYPE (op);
6665 value_range_t *vr = get_value_range (op);
6667 if (TYPE_UNSIGNED (type))
6669 val = integer_zero_node;
6675 val = compare_range_with_value (LE_EXPR, vr, integer_zero_node, &sop);
6679 val = compare_range_with_value (GE_EXPR, vr, integer_zero_node,
6684 if (integer_zerop (val))
6685 val = integer_one_node;
6686 else if (integer_onep (val))
6687 val = integer_zero_node;
6692 && (integer_onep (val) || integer_zerop (val)))
6694 if (sop && issue_strict_overflow_warning (WARN_STRICT_OVERFLOW_MISC))
6696 location_t location;
6698 if (!gimple_has_location (stmt))
6699 location = input_location;
6701 location = gimple_location (stmt);
6702 warning_at (location, OPT_Wstrict_overflow,
6703 "assuming signed overflow does not occur when "
6704 "simplifying %<abs (X)%> to %<X%> or %<-X%>");
6707 gimple_assign_set_rhs1 (stmt, op);
6708 if (integer_onep (val))
6709 gimple_assign_set_rhs_code (stmt, NEGATE_EXPR);
6711 gimple_assign_set_rhs_code (stmt, SSA_NAME);
6720 /* We are comparing trees OP0 and OP1 using COND_CODE. OP0 has
6721 a known value range VR.
6723 If there is one and only one value which will satisfy the
6724 conditional, then return that value. Else return NULL. */
6727 test_for_singularity (enum tree_code cond_code, tree op0,
6728 tree op1, value_range_t *vr)
6733 /* Extract minimum/maximum values which satisfy the
6734 the conditional as it was written. */
6735 if (cond_code == LE_EXPR || cond_code == LT_EXPR)
6737 /* This should not be negative infinity; there is no overflow
6739 min = TYPE_MIN_VALUE (TREE_TYPE (op0));
6742 if (cond_code == LT_EXPR && !is_overflow_infinity (max))
6744 tree one = build_int_cst (TREE_TYPE (op0), 1);
6745 max = fold_build2 (MINUS_EXPR, TREE_TYPE (op0), max, one);
6747 TREE_NO_WARNING (max) = 1;
6750 else if (cond_code == GE_EXPR || cond_code == GT_EXPR)
6752 /* This should not be positive infinity; there is no overflow
6754 max = TYPE_MAX_VALUE (TREE_TYPE (op0));
6757 if (cond_code == GT_EXPR && !is_overflow_infinity (min))
6759 tree one = build_int_cst (TREE_TYPE (op0), 1);
6760 min = fold_build2 (PLUS_EXPR, TREE_TYPE (op0), min, one);
6762 TREE_NO_WARNING (min) = 1;
6766 /* Now refine the minimum and maximum values using any
6767 value range information we have for op0. */
6770 if (compare_values (vr->min, min) == 1)
6772 if (compare_values (vr->max, max) == -1)
6775 /* If the new min/max values have converged to a single value,
6776 then there is only one value which can satisfy the condition,
6777 return that value. */
6778 if (operand_equal_p (min, max, 0) && is_gimple_min_invariant (min))
6784 /* Simplify a conditional using a relational operator to an equality
6785 test if the range information indicates only one value can satisfy
6786 the original conditional. */
6789 simplify_cond_using_ranges (gimple stmt)
6791 tree op0 = gimple_cond_lhs (stmt);
6792 tree op1 = gimple_cond_rhs (stmt);
6793 enum tree_code cond_code = gimple_cond_code (stmt);
6795 if (cond_code != NE_EXPR
6796 && cond_code != EQ_EXPR
6797 && TREE_CODE (op0) == SSA_NAME
6798 && INTEGRAL_TYPE_P (TREE_TYPE (op0))
6799 && is_gimple_min_invariant (op1))
6801 value_range_t *vr = get_value_range (op0);
6803 /* If we have range information for OP0, then we might be
6804 able to simplify this conditional. */
6805 if (vr->type == VR_RANGE)
6807 tree new_tree = test_for_singularity (cond_code, op0, op1, vr);
6813 fprintf (dump_file, "Simplified relational ");
6814 print_gimple_stmt (dump_file, stmt, 0, 0);
6815 fprintf (dump_file, " into ");
6818 gimple_cond_set_code (stmt, EQ_EXPR);
6819 gimple_cond_set_lhs (stmt, op0);
6820 gimple_cond_set_rhs (stmt, new_tree);
6826 print_gimple_stmt (dump_file, stmt, 0, 0);
6827 fprintf (dump_file, "\n");
6833 /* Try again after inverting the condition. We only deal
6834 with integral types here, so no need to worry about
6835 issues with inverting FP comparisons. */
6836 cond_code = invert_tree_comparison (cond_code, false);
6837 new_tree = test_for_singularity (cond_code, op0, op1, vr);
6843 fprintf (dump_file, "Simplified relational ");
6844 print_gimple_stmt (dump_file, stmt, 0, 0);
6845 fprintf (dump_file, " into ");
6848 gimple_cond_set_code (stmt, NE_EXPR);
6849 gimple_cond_set_lhs (stmt, op0);
6850 gimple_cond_set_rhs (stmt, new_tree);
6856 print_gimple_stmt (dump_file, stmt, 0, 0);
6857 fprintf (dump_file, "\n");
6868 /* Simplify a switch statement using the value range of the switch
6872 simplify_switch_using_ranges (gimple stmt)
6874 tree op = gimple_switch_index (stmt);
6879 size_t i = 0, j = 0, n, n2;
6883 if (TREE_CODE (op) == SSA_NAME)
6885 vr = get_value_range (op);
6887 /* We can only handle integer ranges. */
6888 if (vr->type != VR_RANGE
6889 || symbolic_range_p (vr))
6892 /* Find case label for min/max of the value range. */
6893 take_default = !find_case_label_range (stmt, vr->min, vr->max, &i, &j);
6895 else if (TREE_CODE (op) == INTEGER_CST)
6897 take_default = !find_case_label_index (stmt, 1, op, &i);
6911 n = gimple_switch_num_labels (stmt);
6913 /* Bail out if this is just all edges taken. */
6919 /* Build a new vector of taken case labels. */
6920 vec2 = make_tree_vec (j - i + 1 + (int)take_default);
6923 /* Add the default edge, if necessary. */
6925 TREE_VEC_ELT (vec2, n2++) = gimple_switch_default_label (stmt);
6927 for (; i <= j; ++i, ++n2)
6928 TREE_VEC_ELT (vec2, n2) = gimple_switch_label (stmt, i);
6930 /* Mark needed edges. */
6931 for (i = 0; i < n2; ++i)
6933 e = find_edge (gimple_bb (stmt),
6934 label_to_block (CASE_LABEL (TREE_VEC_ELT (vec2, i))));
6935 e->aux = (void *)-1;
6938 /* Queue not needed edges for later removal. */
6939 FOR_EACH_EDGE (e, ei, gimple_bb (stmt)->succs)
6941 if (e->aux == (void *)-1)
6947 if (dump_file && (dump_flags & TDF_DETAILS))
6949 fprintf (dump_file, "removing unreachable case label\n");
6951 VEC_safe_push (edge, heap, to_remove_edges, e);
6952 e->flags &= ~EDGE_EXECUTABLE;
6955 /* And queue an update for the stmt. */
6958 VEC_safe_push (switch_update, heap, to_update_switch_stmts, &su);
6962 /* Simplify STMT using ranges if possible. */
6965 simplify_stmt_using_ranges (gimple_stmt_iterator *gsi)
6967 gimple stmt = gsi_stmt (*gsi);
6968 if (is_gimple_assign (stmt))
6970 enum tree_code rhs_code = gimple_assign_rhs_code (stmt);
6976 case TRUTH_NOT_EXPR:
6977 case TRUTH_AND_EXPR:
6979 case TRUTH_XOR_EXPR:
6980 /* Transform EQ_EXPR, NE_EXPR, TRUTH_NOT_EXPR into BIT_XOR_EXPR
6981 or identity if the RHS is zero or one, and the LHS are known
6982 to be boolean values. Transform all TRUTH_*_EXPR into
6983 BIT_*_EXPR if both arguments are known to be boolean values. */
6984 if (INTEGRAL_TYPE_P (TREE_TYPE (gimple_assign_rhs1 (stmt))))
6985 return simplify_truth_ops_using_ranges (gsi, stmt);
6988 /* Transform TRUNC_DIV_EXPR and TRUNC_MOD_EXPR into RSHIFT_EXPR
6989 and BIT_AND_EXPR respectively if the first operand is greater
6990 than zero and the second operand is an exact power of two. */
6991 case TRUNC_DIV_EXPR:
6992 case TRUNC_MOD_EXPR:
6993 if (INTEGRAL_TYPE_P (TREE_TYPE (gimple_assign_rhs1 (stmt)))
6994 && integer_pow2p (gimple_assign_rhs2 (stmt)))
6995 return simplify_div_or_mod_using_ranges (stmt);
6998 /* Transform ABS (X) into X or -X as appropriate. */
7000 if (TREE_CODE (gimple_assign_rhs1 (stmt)) == SSA_NAME
7001 && INTEGRAL_TYPE_P (TREE_TYPE (gimple_assign_rhs1 (stmt))))
7002 return simplify_abs_using_ranges (stmt);
7009 else if (gimple_code (stmt) == GIMPLE_COND)
7010 return simplify_cond_using_ranges (stmt);
7011 else if (gimple_code (stmt) == GIMPLE_SWITCH)
7012 return simplify_switch_using_ranges (stmt);
7017 /* If the statement pointed by SI has a predicate whose value can be
7018 computed using the value range information computed by VRP, compute
7019 its value and return true. Otherwise, return false. */
7022 fold_predicate_in (gimple_stmt_iterator *si)
7024 bool assignment_p = false;
7026 gimple stmt = gsi_stmt (*si);
7028 if (is_gimple_assign (stmt)
7029 && TREE_CODE_CLASS (gimple_assign_rhs_code (stmt)) == tcc_comparison)
7031 assignment_p = true;
7032 val = vrp_evaluate_conditional (gimple_assign_rhs_code (stmt),
7033 gimple_assign_rhs1 (stmt),
7034 gimple_assign_rhs2 (stmt),
7037 else if (gimple_code (stmt) == GIMPLE_COND)
7038 val = vrp_evaluate_conditional (gimple_cond_code (stmt),
7039 gimple_cond_lhs (stmt),
7040 gimple_cond_rhs (stmt),
7048 val = fold_convert (gimple_expr_type (stmt), val);
7052 fprintf (dump_file, "Folding predicate ");
7053 print_gimple_expr (dump_file, stmt, 0, 0);
7054 fprintf (dump_file, " to ");
7055 print_generic_expr (dump_file, val, 0);
7056 fprintf (dump_file, "\n");
7059 if (is_gimple_assign (stmt))
7060 gimple_assign_set_rhs_from_tree (si, val);
7063 gcc_assert (gimple_code (stmt) == GIMPLE_COND);
7064 if (integer_zerop (val))
7065 gimple_cond_make_false (stmt);
7066 else if (integer_onep (val))
7067 gimple_cond_make_true (stmt);
7078 /* Callback for substitute_and_fold folding the stmt at *SI. */
7081 vrp_fold_stmt (gimple_stmt_iterator *si)
7083 if (fold_predicate_in (si))
7086 return simplify_stmt_using_ranges (si);
7089 /* Stack of dest,src equivalency pairs that need to be restored after
7090 each attempt to thread a block's incoming edge to an outgoing edge.
7092 A NULL entry is used to mark the end of pairs which need to be
7094 static VEC(tree,heap) *stack;
7096 /* A trivial wrapper so that we can present the generic jump threading
7097 code with a simple API for simplifying statements. STMT is the
7098 statement we want to simplify, WITHIN_STMT provides the location
7099 for any overflow warnings. */
7102 simplify_stmt_for_jump_threading (gimple stmt, gimple within_stmt)
7104 /* We only use VRP information to simplify conditionals. This is
7105 overly conservative, but it's unclear if doing more would be
7106 worth the compile time cost. */
7107 if (gimple_code (stmt) != GIMPLE_COND)
7110 return vrp_evaluate_conditional (gimple_cond_code (stmt),
7111 gimple_cond_lhs (stmt),
7112 gimple_cond_rhs (stmt), within_stmt);
7115 /* Blocks which have more than one predecessor and more than
7116 one successor present jump threading opportunities, i.e.,
7117 when the block is reached from a specific predecessor, we
7118 may be able to determine which of the outgoing edges will
7119 be traversed. When this optimization applies, we are able
7120 to avoid conditionals at runtime and we may expose secondary
7121 optimization opportunities.
7123 This routine is effectively a driver for the generic jump
7124 threading code. It basically just presents the generic code
7125 with edges that may be suitable for jump threading.
7127 Unlike DOM, we do not iterate VRP if jump threading was successful.
7128 While iterating may expose new opportunities for VRP, it is expected
7129 those opportunities would be very limited and the compile time cost
7130 to expose those opportunities would be significant.
7132 As jump threading opportunities are discovered, they are registered
7133 for later realization. */
7136 identify_jump_threads (void)
7143 /* Ugh. When substituting values earlier in this pass we can
7144 wipe the dominance information. So rebuild the dominator
7145 information as we need it within the jump threading code. */
7146 calculate_dominance_info (CDI_DOMINATORS);
7148 /* We do not allow VRP information to be used for jump threading
7149 across a back edge in the CFG. Otherwise it becomes too
7150 difficult to avoid eliminating loop exit tests. Of course
7151 EDGE_DFS_BACK is not accurate at this time so we have to
7153 mark_dfs_back_edges ();
7155 /* Do not thread across edges we are about to remove. Just marking
7156 them as EDGE_DFS_BACK will do. */
7157 for (i = 0; VEC_iterate (edge, to_remove_edges, i, e); ++i)
7158 e->flags |= EDGE_DFS_BACK;
7160 /* Allocate our unwinder stack to unwind any temporary equivalences
7161 that might be recorded. */
7162 stack = VEC_alloc (tree, heap, 20);
7164 /* To avoid lots of silly node creation, we create a single
7165 conditional and just modify it in-place when attempting to
7167 dummy = gimple_build_cond (EQ_EXPR,
7168 integer_zero_node, integer_zero_node,
7171 /* Walk through all the blocks finding those which present a
7172 potential jump threading opportunity. We could set this up
7173 as a dominator walker and record data during the walk, but
7174 I doubt it's worth the effort for the classes of jump
7175 threading opportunities we are trying to identify at this
7176 point in compilation. */
7181 /* If the generic jump threading code does not find this block
7182 interesting, then there is nothing to do. */
7183 if (! potentially_threadable_block (bb))
7186 /* We only care about blocks ending in a COND_EXPR. While there
7187 may be some value in handling SWITCH_EXPR here, I doubt it's
7188 terribly important. */
7189 last = gsi_stmt (gsi_last_bb (bb));
7190 if (gimple_code (last) != GIMPLE_COND)
7193 /* We're basically looking for any kind of conditional with
7194 integral type arguments. */
7195 if (TREE_CODE (gimple_cond_lhs (last)) == SSA_NAME
7196 && INTEGRAL_TYPE_P (TREE_TYPE (gimple_cond_lhs (last)))
7197 && (TREE_CODE (gimple_cond_rhs (last)) == SSA_NAME
7198 || is_gimple_min_invariant (gimple_cond_rhs (last)))
7199 && INTEGRAL_TYPE_P (TREE_TYPE (gimple_cond_rhs (last))))
7203 /* We've got a block with multiple predecessors and multiple
7204 successors which also ends in a suitable conditional. For
7205 each predecessor, see if we can thread it to a specific
7207 FOR_EACH_EDGE (e, ei, bb->preds)
7209 /* Do not thread across back edges or abnormal edges
7211 if (e->flags & (EDGE_DFS_BACK | EDGE_COMPLEX))
7214 thread_across_edge (dummy, e, true, &stack,
7215 simplify_stmt_for_jump_threading);
7220 /* We do not actually update the CFG or SSA graphs at this point as
7221 ASSERT_EXPRs are still in the IL and cfg cleanup code does not yet
7222 handle ASSERT_EXPRs gracefully. */
7225 /* We identified all the jump threading opportunities earlier, but could
7226 not transform the CFG at that time. This routine transforms the
7227 CFG and arranges for the dominator tree to be rebuilt if necessary.
7229 Note the SSA graph update will occur during the normal TODO
7230 processing by the pass manager. */
7232 finalize_jump_threads (void)
7234 thread_through_all_blocks (false);
7235 VEC_free (tree, heap, stack);
7239 /* Traverse all the blocks folding conditionals with known ranges. */
7245 prop_value_t *single_val_range;
7246 bool do_value_subst_p;
7250 fprintf (dump_file, "\nValue ranges after VRP:\n\n");
7251 dump_all_value_ranges (dump_file);
7252 fprintf (dump_file, "\n");
7255 /* We may have ended with ranges that have exactly one value. Those
7256 values can be substituted as any other const propagated
7257 value using substitute_and_fold. */
7258 single_val_range = XCNEWVEC (prop_value_t, num_ssa_names);
7260 do_value_subst_p = false;
7261 for (i = 0; i < num_ssa_names; i++)
7263 && vr_value[i]->type == VR_RANGE
7264 && vr_value[i]->min == vr_value[i]->max
7265 && is_gimple_min_invariant (vr_value[i]->min))
7267 single_val_range[i].value = vr_value[i]->min;
7268 do_value_subst_p = true;
7271 if (!do_value_subst_p)
7273 /* We found no single-valued ranges, don't waste time trying to
7274 do single value substitution in substitute_and_fold. */
7275 free (single_val_range);
7276 single_val_range = NULL;
7279 substitute_and_fold (single_val_range, vrp_fold_stmt);
7281 if (warn_array_bounds)
7282 check_all_array_refs ();
7284 /* We must identify jump threading opportunities before we release
7285 the datastructures built by VRP. */
7286 identify_jump_threads ();
7288 /* Free allocated memory. */
7289 for (i = 0; i < num_ssa_names; i++)
7292 BITMAP_FREE (vr_value[i]->equiv);
7296 free (single_val_range);
7298 free (vr_phi_edge_counts);
7300 /* So that we can distinguish between VRP data being available
7301 and not available. */
7303 vr_phi_edge_counts = NULL;
7307 /* Main entry point to VRP (Value Range Propagation). This pass is
7308 loosely based on J. R. C. Patterson, ``Accurate Static Branch
7309 Prediction by Value Range Propagation,'' in SIGPLAN Conference on
7310 Programming Language Design and Implementation, pp. 67-78, 1995.
7311 Also available at http://citeseer.ist.psu.edu/patterson95accurate.html
7313 This is essentially an SSA-CCP pass modified to deal with ranges
7314 instead of constants.
7316 While propagating ranges, we may find that two or more SSA name
7317 have equivalent, though distinct ranges. For instance,
7320 2 p_4 = ASSERT_EXPR <p_3, p_3 != 0>
7322 4 p_5 = ASSERT_EXPR <p_4, p_4 == q_2>;
7326 In the code above, pointer p_5 has range [q_2, q_2], but from the
7327 code we can also determine that p_5 cannot be NULL and, if q_2 had
7328 a non-varying range, p_5's range should also be compatible with it.
7330 These equivalences are created by two expressions: ASSERT_EXPR and
7331 copy operations. Since p_5 is an assertion on p_4, and p_4 was the
7332 result of another assertion, then we can use the fact that p_5 and
7333 p_4 are equivalent when evaluating p_5's range.
7335 Together with value ranges, we also propagate these equivalences
7336 between names so that we can take advantage of information from
7337 multiple ranges when doing final replacement. Note that this
7338 equivalency relation is transitive but not symmetric.
7340 In the example above, p_5 is equivalent to p_4, q_2 and p_3, but we
7341 cannot assert that q_2 is equivalent to p_5 because q_2 may be used
7342 in contexts where that assertion does not hold (e.g., in line 6).
7344 TODO, the main difference between this pass and Patterson's is that
7345 we do not propagate edge probabilities. We only compute whether
7346 edges can be taken or not. That is, instead of having a spectrum
7347 of jump probabilities between 0 and 1, we only deal with 0, 1 and
7348 DON'T KNOW. In the future, it may be worthwhile to propagate
7349 probabilities to aid branch prediction. */
7358 loop_optimizer_init (LOOPS_NORMAL | LOOPS_HAVE_RECORDED_EXITS);
7359 rewrite_into_loop_closed_ssa (NULL, TODO_update_ssa);
7362 insert_range_assertions ();
7364 to_remove_edges = VEC_alloc (edge, heap, 10);
7365 to_update_switch_stmts = VEC_alloc (switch_update, heap, 5);
7366 threadedge_initialize_values ();
7369 ssa_propagate (vrp_visit_stmt, vrp_visit_phi_node);
7372 /* ASSERT_EXPRs must be removed before finalizing jump threads
7373 as finalizing jump threads calls the CFG cleanup code which
7374 does not properly handle ASSERT_EXPRs. */
7375 remove_range_assertions ();
7377 /* If we exposed any new variables, go ahead and put them into
7378 SSA form now, before we handle jump threading. This simplifies
7379 interactions between rewriting of _DECL nodes into SSA form
7380 and rewriting SSA_NAME nodes into SSA form after block
7381 duplication and CFG manipulation. */
7382 update_ssa (TODO_update_ssa);
7384 finalize_jump_threads ();
7386 /* Remove dead edges from SWITCH_EXPR optimization. This leaves the
7387 CFG in a broken state and requires a cfg_cleanup run. */
7388 for (i = 0; VEC_iterate (edge, to_remove_edges, i, e); ++i)
7390 /* Update SWITCH_EXPR case label vector. */
7391 for (i = 0; VEC_iterate (switch_update, to_update_switch_stmts, i, su); ++i)
7394 size_t n = TREE_VEC_LENGTH (su->vec);
7396 gimple_switch_set_num_labels (su->stmt, n);
7397 for (j = 0; j < n; j++)
7398 gimple_switch_set_label (su->stmt, j, TREE_VEC_ELT (su->vec, j));
7399 /* As we may have replaced the default label with a regular one
7400 make sure to make it a real default label again. This ensures
7401 optimal expansion. */
7402 label = gimple_switch_default_label (su->stmt);
7403 CASE_LOW (label) = NULL_TREE;
7404 CASE_HIGH (label) = NULL_TREE;
7407 if (VEC_length (edge, to_remove_edges) > 0)
7408 free_dominance_info (CDI_DOMINATORS);
7410 VEC_free (edge, heap, to_remove_edges);
7411 VEC_free (switch_update, heap, to_update_switch_stmts);
7412 threadedge_finalize_values ();
7415 loop_optimizer_finalize ();
7422 return flag_tree_vrp != 0;
7425 struct gimple_opt_pass pass_vrp =
7430 gate_vrp, /* gate */
7431 execute_vrp, /* execute */
7434 0, /* static_pass_number */
7435 TV_TREE_VRP, /* tv_id */
7436 PROP_ssa, /* properties_required */
7437 0, /* properties_provided */
7438 0, /* properties_destroyed */
7439 0, /* todo_flags_start */
7444 | TODO_update_ssa /* todo_flags_finish */