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 && !is_overflow_infinity (vr0.max)
2720 && (TYPE_PRECISION (outer_type) >= TYPE_PRECISION (inner_type)
2721 || (vr0.type == VR_RANGE
2722 && integer_zerop (int_const_binop (RSHIFT_EXPR,
2723 int_const_binop (MINUS_EXPR, vr0.max, vr0.min, 0),
2724 size_int (TYPE_PRECISION (outer_type)), 0)))))
2726 tree new_min, new_max;
2727 new_min = force_fit_type_double (outer_type,
2728 TREE_INT_CST_LOW (vr0.min),
2729 TREE_INT_CST_HIGH (vr0.min), 0, 0);
2730 new_max = force_fit_type_double (outer_type,
2731 TREE_INT_CST_LOW (vr0.max),
2732 TREE_INT_CST_HIGH (vr0.max), 0, 0);
2733 set_and_canonicalize_value_range (vr, vr0.type,
2734 new_min, new_max, NULL);
2738 set_value_range_to_varying (vr);
2742 /* Conversion of a VR_VARYING value to a wider type can result
2743 in a usable range. So wait until after we've handled conversions
2744 before dropping the result to VR_VARYING if we had a source
2745 operand that is VR_VARYING. */
2746 if (vr0.type == VR_VARYING)
2748 set_value_range_to_varying (vr);
2752 /* Apply the operation to each end of the range and see what we end
2754 if (code == NEGATE_EXPR
2755 && !TYPE_UNSIGNED (type))
2757 /* NEGATE_EXPR flips the range around. We need to treat
2758 TYPE_MIN_VALUE specially. */
2759 if (is_positive_overflow_infinity (vr0.max))
2760 min = negative_overflow_infinity (type);
2761 else if (is_negative_overflow_infinity (vr0.max))
2762 min = positive_overflow_infinity (type);
2763 else if (!vrp_val_is_min (vr0.max))
2764 min = fold_unary_to_constant (code, type, vr0.max);
2765 else if (needs_overflow_infinity (type))
2767 if (supports_overflow_infinity (type)
2768 && !is_overflow_infinity (vr0.min)
2769 && !vrp_val_is_min (vr0.min))
2770 min = positive_overflow_infinity (type);
2773 set_value_range_to_varying (vr);
2778 min = TYPE_MIN_VALUE (type);
2780 if (is_positive_overflow_infinity (vr0.min))
2781 max = negative_overflow_infinity (type);
2782 else if (is_negative_overflow_infinity (vr0.min))
2783 max = positive_overflow_infinity (type);
2784 else if (!vrp_val_is_min (vr0.min))
2785 max = fold_unary_to_constant (code, type, vr0.min);
2786 else if (needs_overflow_infinity (type))
2788 if (supports_overflow_infinity (type))
2789 max = positive_overflow_infinity (type);
2792 set_value_range_to_varying (vr);
2797 max = TYPE_MIN_VALUE (type);
2799 else if (code == NEGATE_EXPR
2800 && TYPE_UNSIGNED (type))
2802 if (!range_includes_zero_p (&vr0))
2804 max = fold_unary_to_constant (code, type, vr0.min);
2805 min = fold_unary_to_constant (code, type, vr0.max);
2809 if (range_is_null (&vr0))
2810 set_value_range_to_null (vr, type);
2812 set_value_range_to_varying (vr);
2816 else if (code == ABS_EXPR
2817 && !TYPE_UNSIGNED (type))
2819 /* -TYPE_MIN_VALUE = TYPE_MIN_VALUE with flag_wrapv so we can't get a
2821 if (!TYPE_OVERFLOW_UNDEFINED (type)
2822 && ((vr0.type == VR_RANGE
2823 && vrp_val_is_min (vr0.min))
2824 || (vr0.type == VR_ANTI_RANGE
2825 && !vrp_val_is_min (vr0.min)
2826 && !range_includes_zero_p (&vr0))))
2828 set_value_range_to_varying (vr);
2832 /* ABS_EXPR may flip the range around, if the original range
2833 included negative values. */
2834 if (is_overflow_infinity (vr0.min))
2835 min = positive_overflow_infinity (type);
2836 else if (!vrp_val_is_min (vr0.min))
2837 min = fold_unary_to_constant (code, type, vr0.min);
2838 else if (!needs_overflow_infinity (type))
2839 min = TYPE_MAX_VALUE (type);
2840 else if (supports_overflow_infinity (type))
2841 min = positive_overflow_infinity (type);
2844 set_value_range_to_varying (vr);
2848 if (is_overflow_infinity (vr0.max))
2849 max = positive_overflow_infinity (type);
2850 else if (!vrp_val_is_min (vr0.max))
2851 max = fold_unary_to_constant (code, type, vr0.max);
2852 else if (!needs_overflow_infinity (type))
2853 max = TYPE_MAX_VALUE (type);
2854 else if (supports_overflow_infinity (type)
2855 /* We shouldn't generate [+INF, +INF] as set_value_range
2856 doesn't like this and ICEs. */
2857 && !is_positive_overflow_infinity (min))
2858 max = positive_overflow_infinity (type);
2861 set_value_range_to_varying (vr);
2865 cmp = compare_values (min, max);
2867 /* If a VR_ANTI_RANGEs contains zero, then we have
2868 ~[-INF, min(MIN, MAX)]. */
2869 if (vr0.type == VR_ANTI_RANGE)
2871 if (range_includes_zero_p (&vr0))
2873 /* Take the lower of the two values. */
2877 /* Create ~[-INF, min (abs(MIN), abs(MAX))]
2878 or ~[-INF + 1, min (abs(MIN), abs(MAX))] when
2879 flag_wrapv is set and the original anti-range doesn't include
2880 TYPE_MIN_VALUE, remember -TYPE_MIN_VALUE = TYPE_MIN_VALUE. */
2881 if (TYPE_OVERFLOW_WRAPS (type))
2883 tree type_min_value = TYPE_MIN_VALUE (type);
2885 min = (vr0.min != type_min_value
2886 ? int_const_binop (PLUS_EXPR, type_min_value,
2887 integer_one_node, 0)
2892 if (overflow_infinity_range_p (&vr0))
2893 min = negative_overflow_infinity (type);
2895 min = TYPE_MIN_VALUE (type);
2900 /* All else has failed, so create the range [0, INF], even for
2901 flag_wrapv since TYPE_MIN_VALUE is in the original
2903 vr0.type = VR_RANGE;
2904 min = build_int_cst (type, 0);
2905 if (needs_overflow_infinity (type))
2907 if (supports_overflow_infinity (type))
2908 max = positive_overflow_infinity (type);
2911 set_value_range_to_varying (vr);
2916 max = TYPE_MAX_VALUE (type);
2920 /* If the range contains zero then we know that the minimum value in the
2921 range will be zero. */
2922 else if (range_includes_zero_p (&vr0))
2926 min = build_int_cst (type, 0);
2930 /* If the range was reversed, swap MIN and MAX. */
2941 /* Otherwise, operate on each end of the range. */
2942 min = fold_unary_to_constant (code, type, vr0.min);
2943 max = fold_unary_to_constant (code, type, vr0.max);
2945 if (needs_overflow_infinity (type))
2947 gcc_assert (code != NEGATE_EXPR && code != ABS_EXPR);
2949 /* If both sides have overflowed, we don't know
2951 if ((is_overflow_infinity (vr0.min)
2952 || TREE_OVERFLOW (min))
2953 && (is_overflow_infinity (vr0.max)
2954 || TREE_OVERFLOW (max)))
2956 set_value_range_to_varying (vr);
2960 if (is_overflow_infinity (vr0.min))
2962 else if (TREE_OVERFLOW (min))
2964 if (supports_overflow_infinity (type))
2965 min = (tree_int_cst_sgn (min) >= 0
2966 ? positive_overflow_infinity (TREE_TYPE (min))
2967 : negative_overflow_infinity (TREE_TYPE (min)));
2970 set_value_range_to_varying (vr);
2975 if (is_overflow_infinity (vr0.max))
2977 else if (TREE_OVERFLOW (max))
2979 if (supports_overflow_infinity (type))
2980 max = (tree_int_cst_sgn (max) >= 0
2981 ? positive_overflow_infinity (TREE_TYPE (max))
2982 : negative_overflow_infinity (TREE_TYPE (max)));
2985 set_value_range_to_varying (vr);
2992 cmp = compare_values (min, max);
2993 if (cmp == -2 || cmp == 1)
2995 /* If the new range has its limits swapped around (MIN > MAX),
2996 then the operation caused one of them to wrap around, mark
2997 the new range VARYING. */
2998 set_value_range_to_varying (vr);
3001 set_value_range (vr, vr0.type, min, max, NULL);
3005 /* Extract range information from a conditional expression EXPR based on
3006 the ranges of each of its operands and the expression code. */
3009 extract_range_from_cond_expr (value_range_t *vr, tree expr)
3012 value_range_t vr0 = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
3013 value_range_t vr1 = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
3015 /* Get value ranges for each operand. For constant operands, create
3016 a new value range with the operand to simplify processing. */
3017 op0 = COND_EXPR_THEN (expr);
3018 if (TREE_CODE (op0) == SSA_NAME)
3019 vr0 = *(get_value_range (op0));
3020 else if (is_gimple_min_invariant (op0))
3021 set_value_range_to_value (&vr0, op0, NULL);
3023 set_value_range_to_varying (&vr0);
3025 op1 = COND_EXPR_ELSE (expr);
3026 if (TREE_CODE (op1) == SSA_NAME)
3027 vr1 = *(get_value_range (op1));
3028 else if (is_gimple_min_invariant (op1))
3029 set_value_range_to_value (&vr1, op1, NULL);
3031 set_value_range_to_varying (&vr1);
3033 /* The resulting value range is the union of the operand ranges */
3034 vrp_meet (&vr0, &vr1);
3035 copy_value_range (vr, &vr0);
3039 /* Extract range information from a comparison expression EXPR based
3040 on the range of its operand and the expression code. */
3043 extract_range_from_comparison (value_range_t *vr, enum tree_code code,
3044 tree type, tree op0, tree op1)
3049 val = vrp_evaluate_conditional_warnv_with_ops (code, op0, op1, false, &sop,
3052 /* A disadvantage of using a special infinity as an overflow
3053 representation is that we lose the ability to record overflow
3054 when we don't have an infinity. So we have to ignore a result
3055 which relies on overflow. */
3057 if (val && !is_overflow_infinity (val) && !sop)
3059 /* Since this expression was found on the RHS of an assignment,
3060 its type may be different from _Bool. Convert VAL to EXPR's
3062 val = fold_convert (type, val);
3063 if (is_gimple_min_invariant (val))
3064 set_value_range_to_value (vr, val, vr->equiv);
3066 set_value_range (vr, VR_RANGE, val, val, vr->equiv);
3069 /* The result of a comparison is always true or false. */
3070 set_value_range_to_truthvalue (vr, type);
3073 /* Try to derive a nonnegative or nonzero range out of STMT relying
3074 primarily on generic routines in fold in conjunction with range data.
3075 Store the result in *VR */
3078 extract_range_basic (value_range_t *vr, gimple stmt)
3081 tree type = gimple_expr_type (stmt);
3083 if (INTEGRAL_TYPE_P (type)
3084 && gimple_stmt_nonnegative_warnv_p (stmt, &sop))
3085 set_value_range_to_nonnegative (vr, type,
3086 sop || stmt_overflow_infinity (stmt));
3087 else if (vrp_stmt_computes_nonzero (stmt, &sop)
3089 set_value_range_to_nonnull (vr, type);
3091 set_value_range_to_varying (vr);
3095 /* Try to compute a useful range out of assignment STMT and store it
3099 extract_range_from_assignment (value_range_t *vr, gimple stmt)
3101 enum tree_code code = gimple_assign_rhs_code (stmt);
3103 if (code == ASSERT_EXPR)
3104 extract_range_from_assert (vr, gimple_assign_rhs1 (stmt));
3105 else if (code == SSA_NAME)
3106 extract_range_from_ssa_name (vr, gimple_assign_rhs1 (stmt));
3107 else if (TREE_CODE_CLASS (code) == tcc_binary
3108 || code == TRUTH_AND_EXPR
3109 || code == TRUTH_OR_EXPR
3110 || code == TRUTH_XOR_EXPR)
3111 extract_range_from_binary_expr (vr, gimple_assign_rhs_code (stmt),
3112 gimple_expr_type (stmt),
3113 gimple_assign_rhs1 (stmt),
3114 gimple_assign_rhs2 (stmt));
3115 else if (TREE_CODE_CLASS (code) == tcc_unary)
3116 extract_range_from_unary_expr (vr, gimple_assign_rhs_code (stmt),
3117 gimple_expr_type (stmt),
3118 gimple_assign_rhs1 (stmt));
3119 else if (code == COND_EXPR)
3120 extract_range_from_cond_expr (vr, gimple_assign_rhs1 (stmt));
3121 else if (TREE_CODE_CLASS (code) == tcc_comparison)
3122 extract_range_from_comparison (vr, gimple_assign_rhs_code (stmt),
3123 gimple_expr_type (stmt),
3124 gimple_assign_rhs1 (stmt),
3125 gimple_assign_rhs2 (stmt));
3126 else if (get_gimple_rhs_class (code) == GIMPLE_SINGLE_RHS
3127 && is_gimple_min_invariant (gimple_assign_rhs1 (stmt)))
3128 set_value_range_to_value (vr, gimple_assign_rhs1 (stmt), NULL);
3130 set_value_range_to_varying (vr);
3132 if (vr->type == VR_VARYING)
3133 extract_range_basic (vr, stmt);
3136 /* Given a range VR, a LOOP and a variable VAR, determine whether it
3137 would be profitable to adjust VR using scalar evolution information
3138 for VAR. If so, update VR with the new limits. */
3141 adjust_range_with_scev (value_range_t *vr, struct loop *loop,
3142 gimple stmt, tree var)
3144 tree init, step, chrec, tmin, tmax, min, max, type;
3145 enum ev_direction dir;
3147 /* TODO. Don't adjust anti-ranges. An anti-range may provide
3148 better opportunities than a regular range, but I'm not sure. */
3149 if (vr->type == VR_ANTI_RANGE)
3152 chrec = instantiate_parameters (loop, analyze_scalar_evolution (loop, var));
3154 /* Like in PR19590, scev can return a constant function. */
3155 if (is_gimple_min_invariant (chrec))
3157 set_value_range_to_value (vr, chrec, vr->equiv);
3161 if (TREE_CODE (chrec) != POLYNOMIAL_CHREC)
3164 init = initial_condition_in_loop_num (chrec, loop->num);
3165 step = evolution_part_in_loop_num (chrec, loop->num);
3167 /* If STEP is symbolic, we can't know whether INIT will be the
3168 minimum or maximum value in the range. Also, unless INIT is
3169 a simple expression, compare_values and possibly other functions
3170 in tree-vrp won't be able to handle it. */
3171 if (step == NULL_TREE
3172 || !is_gimple_min_invariant (step)
3173 || !valid_value_p (init))
3176 dir = scev_direction (chrec);
3177 if (/* Do not adjust ranges if we do not know whether the iv increases
3178 or decreases, ... */
3179 dir == EV_DIR_UNKNOWN
3180 /* ... or if it may wrap. */
3181 || scev_probably_wraps_p (init, step, stmt, get_chrec_loop (chrec),
3185 /* We use TYPE_MIN_VALUE and TYPE_MAX_VALUE here instead of
3186 negative_overflow_infinity and positive_overflow_infinity,
3187 because we have concluded that the loop probably does not
3190 type = TREE_TYPE (var);
3191 if (POINTER_TYPE_P (type) || !TYPE_MIN_VALUE (type))
3192 tmin = lower_bound_in_type (type, type);
3194 tmin = TYPE_MIN_VALUE (type);
3195 if (POINTER_TYPE_P (type) || !TYPE_MAX_VALUE (type))
3196 tmax = upper_bound_in_type (type, type);
3198 tmax = TYPE_MAX_VALUE (type);
3200 if (vr->type == VR_VARYING || vr->type == VR_UNDEFINED)
3205 /* For VARYING or UNDEFINED ranges, just about anything we get
3206 from scalar evolutions should be better. */
3208 if (dir == EV_DIR_DECREASES)
3213 /* If we would create an invalid range, then just assume we
3214 know absolutely nothing. This may be over-conservative,
3215 but it's clearly safe, and should happen only in unreachable
3216 parts of code, or for invalid programs. */
3217 if (compare_values (min, max) == 1)
3220 set_value_range (vr, VR_RANGE, min, max, vr->equiv);
3222 else if (vr->type == VR_RANGE)
3227 if (dir == EV_DIR_DECREASES)
3229 /* INIT is the maximum value. If INIT is lower than VR->MAX
3230 but no smaller than VR->MIN, set VR->MAX to INIT. */
3231 if (compare_values (init, max) == -1)
3235 /* If we just created an invalid range with the minimum
3236 greater than the maximum, we fail conservatively.
3237 This should happen only in unreachable
3238 parts of code, or for invalid programs. */
3239 if (compare_values (min, max) == 1)
3243 /* According to the loop information, the variable does not
3244 overflow. If we think it does, probably because of an
3245 overflow due to arithmetic on a different INF value,
3247 if (is_negative_overflow_infinity (min))
3252 /* If INIT is bigger than VR->MIN, set VR->MIN to INIT. */
3253 if (compare_values (init, min) == 1)
3257 /* Again, avoid creating invalid range by failing. */
3258 if (compare_values (min, max) == 1)
3262 if (is_positive_overflow_infinity (max))
3266 set_value_range (vr, VR_RANGE, min, max, vr->equiv);
3270 /* Return true if VAR may overflow at STMT. This checks any available
3271 loop information to see if we can determine that VAR does not
3275 vrp_var_may_overflow (tree var, gimple stmt)
3278 tree chrec, init, step;
3280 if (current_loops == NULL)
3283 l = loop_containing_stmt (stmt);
3288 chrec = instantiate_parameters (l, analyze_scalar_evolution (l, var));
3289 if (TREE_CODE (chrec) != POLYNOMIAL_CHREC)
3292 init = initial_condition_in_loop_num (chrec, l->num);
3293 step = evolution_part_in_loop_num (chrec, l->num);
3295 if (step == NULL_TREE
3296 || !is_gimple_min_invariant (step)
3297 || !valid_value_p (init))
3300 /* If we get here, we know something useful about VAR based on the
3301 loop information. If it wraps, it may overflow. */
3303 if (scev_probably_wraps_p (init, step, stmt, get_chrec_loop (chrec),
3307 if (dump_file && (dump_flags & TDF_DETAILS) != 0)
3309 print_generic_expr (dump_file, var, 0);
3310 fprintf (dump_file, ": loop information indicates does not overflow\n");
3317 /* Given two numeric value ranges VR0, VR1 and a comparison code COMP:
3319 - Return BOOLEAN_TRUE_NODE if VR0 COMP VR1 always returns true for
3320 all the values in the ranges.
3322 - Return BOOLEAN_FALSE_NODE if the comparison always returns false.
3324 - Return NULL_TREE if it is not always possible to determine the
3325 value of the comparison.
3327 Also set *STRICT_OVERFLOW_P to indicate whether a range with an
3328 overflow infinity was used in the test. */
3332 compare_ranges (enum tree_code comp, value_range_t *vr0, value_range_t *vr1,
3333 bool *strict_overflow_p)
3335 /* VARYING or UNDEFINED ranges cannot be compared. */
3336 if (vr0->type == VR_VARYING
3337 || vr0->type == VR_UNDEFINED
3338 || vr1->type == VR_VARYING
3339 || vr1->type == VR_UNDEFINED)
3342 /* Anti-ranges need to be handled separately. */
3343 if (vr0->type == VR_ANTI_RANGE || vr1->type == VR_ANTI_RANGE)
3345 /* If both are anti-ranges, then we cannot compute any
3347 if (vr0->type == VR_ANTI_RANGE && vr1->type == VR_ANTI_RANGE)
3350 /* These comparisons are never statically computable. */
3357 /* Equality can be computed only between a range and an
3358 anti-range. ~[VAL1, VAL2] == [VAL1, VAL2] is always false. */
3359 if (vr0->type == VR_RANGE)
3361 /* To simplify processing, make VR0 the anti-range. */
3362 value_range_t *tmp = vr0;
3367 gcc_assert (comp == NE_EXPR || comp == EQ_EXPR);
3369 if (compare_values_warnv (vr0->min, vr1->min, strict_overflow_p) == 0
3370 && compare_values_warnv (vr0->max, vr1->max, strict_overflow_p) == 0)
3371 return (comp == NE_EXPR) ? boolean_true_node : boolean_false_node;
3376 if (!usable_range_p (vr0, strict_overflow_p)
3377 || !usable_range_p (vr1, strict_overflow_p))
3380 /* Simplify processing. If COMP is GT_EXPR or GE_EXPR, switch the
3381 operands around and change the comparison code. */
3382 if (comp == GT_EXPR || comp == GE_EXPR)
3385 comp = (comp == GT_EXPR) ? LT_EXPR : LE_EXPR;
3391 if (comp == EQ_EXPR)
3393 /* Equality may only be computed if both ranges represent
3394 exactly one value. */
3395 if (compare_values_warnv (vr0->min, vr0->max, strict_overflow_p) == 0
3396 && compare_values_warnv (vr1->min, vr1->max, strict_overflow_p) == 0)
3398 int cmp_min = compare_values_warnv (vr0->min, vr1->min,
3400 int cmp_max = compare_values_warnv (vr0->max, vr1->max,
3402 if (cmp_min == 0 && cmp_max == 0)
3403 return boolean_true_node;
3404 else if (cmp_min != -2 && cmp_max != -2)
3405 return boolean_false_node;
3407 /* If [V0_MIN, V1_MAX] < [V1_MIN, V1_MAX] then V0 != V1. */
3408 else if (compare_values_warnv (vr0->min, vr1->max,
3409 strict_overflow_p) == 1
3410 || compare_values_warnv (vr1->min, vr0->max,
3411 strict_overflow_p) == 1)
3412 return boolean_false_node;
3416 else if (comp == NE_EXPR)
3420 /* If VR0 is completely to the left or completely to the right
3421 of VR1, they are always different. Notice that we need to
3422 make sure that both comparisons yield similar results to
3423 avoid comparing values that cannot be compared at
3425 cmp1 = compare_values_warnv (vr0->max, vr1->min, strict_overflow_p);
3426 cmp2 = compare_values_warnv (vr0->min, vr1->max, strict_overflow_p);
3427 if ((cmp1 == -1 && cmp2 == -1) || (cmp1 == 1 && cmp2 == 1))
3428 return boolean_true_node;
3430 /* If VR0 and VR1 represent a single value and are identical,
3432 else if (compare_values_warnv (vr0->min, vr0->max,
3433 strict_overflow_p) == 0
3434 && compare_values_warnv (vr1->min, vr1->max,
3435 strict_overflow_p) == 0
3436 && compare_values_warnv (vr0->min, vr1->min,
3437 strict_overflow_p) == 0
3438 && compare_values_warnv (vr0->max, vr1->max,
3439 strict_overflow_p) == 0)
3440 return boolean_false_node;
3442 /* Otherwise, they may or may not be different. */
3446 else if (comp == LT_EXPR || comp == LE_EXPR)
3450 /* If VR0 is to the left of VR1, return true. */
3451 tst = compare_values_warnv (vr0->max, vr1->min, strict_overflow_p);
3452 if ((comp == LT_EXPR && tst == -1)
3453 || (comp == LE_EXPR && (tst == -1 || tst == 0)))
3455 if (overflow_infinity_range_p (vr0)
3456 || overflow_infinity_range_p (vr1))
3457 *strict_overflow_p = true;
3458 return boolean_true_node;
3461 /* If VR0 is to the right of VR1, return false. */
3462 tst = compare_values_warnv (vr0->min, vr1->max, strict_overflow_p);
3463 if ((comp == LT_EXPR && (tst == 0 || tst == 1))
3464 || (comp == LE_EXPR && tst == 1))
3466 if (overflow_infinity_range_p (vr0)
3467 || overflow_infinity_range_p (vr1))
3468 *strict_overflow_p = true;
3469 return boolean_false_node;
3472 /* Otherwise, we don't know. */
3480 /* Given a value range VR, a value VAL and a comparison code COMP, return
3481 BOOLEAN_TRUE_NODE if VR COMP VAL always returns true for all the
3482 values in VR. Return BOOLEAN_FALSE_NODE if the comparison
3483 always returns false. Return NULL_TREE if it is not always
3484 possible to determine the value of the comparison. Also set
3485 *STRICT_OVERFLOW_P to indicate whether a range with an overflow
3486 infinity was used in the test. */
3489 compare_range_with_value (enum tree_code comp, value_range_t *vr, tree val,
3490 bool *strict_overflow_p)
3492 if (vr->type == VR_VARYING || vr->type == VR_UNDEFINED)
3495 /* Anti-ranges need to be handled separately. */
3496 if (vr->type == VR_ANTI_RANGE)
3498 /* For anti-ranges, the only predicates that we can compute at
3499 compile time are equality and inequality. */
3506 /* ~[VAL_1, VAL_2] OP VAL is known if VAL_1 <= VAL <= VAL_2. */
3507 if (value_inside_range (val, vr) == 1)
3508 return (comp == NE_EXPR) ? boolean_true_node : boolean_false_node;
3513 if (!usable_range_p (vr, strict_overflow_p))
3516 if (comp == EQ_EXPR)
3518 /* EQ_EXPR may only be computed if VR represents exactly
3520 if (compare_values_warnv (vr->min, vr->max, strict_overflow_p) == 0)
3522 int cmp = compare_values_warnv (vr->min, val, strict_overflow_p);
3524 return boolean_true_node;
3525 else if (cmp == -1 || cmp == 1 || cmp == 2)
3526 return boolean_false_node;
3528 else if (compare_values_warnv (val, vr->min, strict_overflow_p) == -1
3529 || compare_values_warnv (vr->max, val, strict_overflow_p) == -1)
3530 return boolean_false_node;
3534 else if (comp == NE_EXPR)
3536 /* If VAL is not inside VR, then they are always different. */
3537 if (compare_values_warnv (vr->max, val, strict_overflow_p) == -1
3538 || compare_values_warnv (vr->min, val, strict_overflow_p) == 1)
3539 return boolean_true_node;
3541 /* If VR represents exactly one value equal to VAL, then return
3543 if (compare_values_warnv (vr->min, vr->max, strict_overflow_p) == 0
3544 && compare_values_warnv (vr->min, val, strict_overflow_p) == 0)
3545 return boolean_false_node;
3547 /* Otherwise, they may or may not be different. */
3550 else if (comp == LT_EXPR || comp == LE_EXPR)
3554 /* If VR is to the left of VAL, return true. */
3555 tst = compare_values_warnv (vr->max, val, strict_overflow_p);
3556 if ((comp == LT_EXPR && tst == -1)
3557 || (comp == LE_EXPR && (tst == -1 || tst == 0)))
3559 if (overflow_infinity_range_p (vr))
3560 *strict_overflow_p = true;
3561 return boolean_true_node;
3564 /* If VR is to the right of VAL, return false. */
3565 tst = compare_values_warnv (vr->min, val, strict_overflow_p);
3566 if ((comp == LT_EXPR && (tst == 0 || tst == 1))
3567 || (comp == LE_EXPR && tst == 1))
3569 if (overflow_infinity_range_p (vr))
3570 *strict_overflow_p = true;
3571 return boolean_false_node;
3574 /* Otherwise, we don't know. */
3577 else if (comp == GT_EXPR || comp == GE_EXPR)
3581 /* If VR is to the right of VAL, return true. */
3582 tst = compare_values_warnv (vr->min, val, strict_overflow_p);
3583 if ((comp == GT_EXPR && tst == 1)
3584 || (comp == GE_EXPR && (tst == 0 || tst == 1)))
3586 if (overflow_infinity_range_p (vr))
3587 *strict_overflow_p = true;
3588 return boolean_true_node;
3591 /* If VR is to the left of VAL, return false. */
3592 tst = compare_values_warnv (vr->max, val, strict_overflow_p);
3593 if ((comp == GT_EXPR && (tst == -1 || tst == 0))
3594 || (comp == GE_EXPR && tst == -1))
3596 if (overflow_infinity_range_p (vr))
3597 *strict_overflow_p = true;
3598 return boolean_false_node;
3601 /* Otherwise, we don't know. */
3609 /* Debugging dumps. */
3611 void dump_value_range (FILE *, value_range_t *);
3612 void debug_value_range (value_range_t *);
3613 void dump_all_value_ranges (FILE *);
3614 void debug_all_value_ranges (void);
3615 void dump_vr_equiv (FILE *, bitmap);
3616 void debug_vr_equiv (bitmap);
3619 /* Dump value range VR to FILE. */
3622 dump_value_range (FILE *file, value_range_t *vr)
3625 fprintf (file, "[]");
3626 else if (vr->type == VR_UNDEFINED)
3627 fprintf (file, "UNDEFINED");
3628 else if (vr->type == VR_RANGE || vr->type == VR_ANTI_RANGE)
3630 tree type = TREE_TYPE (vr->min);
3632 fprintf (file, "%s[", (vr->type == VR_ANTI_RANGE) ? "~" : "");
3634 if (is_negative_overflow_infinity (vr->min))
3635 fprintf (file, "-INF(OVF)");
3636 else if (INTEGRAL_TYPE_P (type)
3637 && !TYPE_UNSIGNED (type)
3638 && vrp_val_is_min (vr->min))
3639 fprintf (file, "-INF");
3641 print_generic_expr (file, vr->min, 0);
3643 fprintf (file, ", ");
3645 if (is_positive_overflow_infinity (vr->max))
3646 fprintf (file, "+INF(OVF)");
3647 else if (INTEGRAL_TYPE_P (type)
3648 && vrp_val_is_max (vr->max))
3649 fprintf (file, "+INF");
3651 print_generic_expr (file, vr->max, 0);
3653 fprintf (file, "]");
3660 fprintf (file, " EQUIVALENCES: { ");
3662 EXECUTE_IF_SET_IN_BITMAP (vr->equiv, 0, i, bi)
3664 print_generic_expr (file, ssa_name (i), 0);
3665 fprintf (file, " ");
3669 fprintf (file, "} (%u elements)", c);
3672 else if (vr->type == VR_VARYING)
3673 fprintf (file, "VARYING");
3675 fprintf (file, "INVALID RANGE");
3679 /* Dump value range VR to stderr. */
3682 debug_value_range (value_range_t *vr)
3684 dump_value_range (stderr, vr);
3685 fprintf (stderr, "\n");
3689 /* Dump value ranges of all SSA_NAMEs to FILE. */
3692 dump_all_value_ranges (FILE *file)
3696 for (i = 0; i < num_ssa_names; i++)
3700 print_generic_expr (file, ssa_name (i), 0);
3701 fprintf (file, ": ");
3702 dump_value_range (file, vr_value[i]);
3703 fprintf (file, "\n");
3707 fprintf (file, "\n");
3711 /* Dump all value ranges to stderr. */
3714 debug_all_value_ranges (void)
3716 dump_all_value_ranges (stderr);
3720 /* Given a COND_EXPR COND of the form 'V OP W', and an SSA name V,
3721 create a new SSA name N and return the assertion assignment
3722 'V = ASSERT_EXPR <V, V OP W>'. */
3725 build_assert_expr_for (tree cond, tree v)
3730 gcc_assert (TREE_CODE (v) == SSA_NAME);
3731 n = duplicate_ssa_name (v, NULL);
3733 if (COMPARISON_CLASS_P (cond))
3735 tree a = build2 (ASSERT_EXPR, TREE_TYPE (v), v, cond);
3736 assertion = gimple_build_assign (n, a);
3738 else if (TREE_CODE (cond) == TRUTH_NOT_EXPR)
3740 /* Given !V, build the assignment N = false. */
3741 tree op0 = TREE_OPERAND (cond, 0);
3742 gcc_assert (op0 == v);
3743 assertion = gimple_build_assign (n, boolean_false_node);
3745 else if (TREE_CODE (cond) == SSA_NAME)
3747 /* Given V, build the assignment N = true. */
3748 gcc_assert (v == cond);
3749 assertion = gimple_build_assign (n, boolean_true_node);
3754 SSA_NAME_DEF_STMT (n) = assertion;
3756 /* The new ASSERT_EXPR, creates a new SSA name that replaces the
3757 operand of the ASSERT_EXPR. Register the new name and the old one
3758 in the replacement table so that we can fix the SSA web after
3759 adding all the ASSERT_EXPRs. */
3760 register_new_name_mapping (n, v);
3766 /* Return false if EXPR is a predicate expression involving floating
3770 fp_predicate (gimple stmt)
3772 GIMPLE_CHECK (stmt, GIMPLE_COND);
3774 return FLOAT_TYPE_P (TREE_TYPE (gimple_cond_lhs (stmt)));
3778 /* If the range of values taken by OP can be inferred after STMT executes,
3779 return the comparison code (COMP_CODE_P) and value (VAL_P) that
3780 describes the inferred range. Return true if a range could be
3784 infer_value_range (gimple stmt, tree op, enum tree_code *comp_code_p, tree *val_p)
3787 *comp_code_p = ERROR_MARK;
3789 /* Do not attempt to infer anything in names that flow through
3791 if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (op))
3794 /* Similarly, don't infer anything from statements that may throw
3796 if (stmt_could_throw_p (stmt))
3799 /* If STMT is the last statement of a basic block with no
3800 successors, there is no point inferring anything about any of its
3801 operands. We would not be able to find a proper insertion point
3802 for the assertion, anyway. */
3803 if (stmt_ends_bb_p (stmt) && EDGE_COUNT (gimple_bb (stmt)->succs) == 0)
3806 /* We can only assume that a pointer dereference will yield
3807 non-NULL if -fdelete-null-pointer-checks is enabled. */
3808 if (flag_delete_null_pointer_checks
3809 && POINTER_TYPE_P (TREE_TYPE (op))
3810 && gimple_code (stmt) != GIMPLE_ASM)
3812 unsigned num_uses, num_loads, num_stores;
3814 count_uses_and_derefs (op, stmt, &num_uses, &num_loads, &num_stores);
3815 if (num_loads + num_stores > 0)
3817 *val_p = build_int_cst (TREE_TYPE (op), 0);
3818 *comp_code_p = NE_EXPR;
3827 void dump_asserts_for (FILE *, tree);
3828 void debug_asserts_for (tree);
3829 void dump_all_asserts (FILE *);
3830 void debug_all_asserts (void);
3832 /* Dump all the registered assertions for NAME to FILE. */
3835 dump_asserts_for (FILE *file, tree name)
3839 fprintf (file, "Assertions to be inserted for ");
3840 print_generic_expr (file, name, 0);
3841 fprintf (file, "\n");
3843 loc = asserts_for[SSA_NAME_VERSION (name)];
3846 fprintf (file, "\t");
3847 print_gimple_stmt (file, gsi_stmt (loc->si), 0, 0);
3848 fprintf (file, "\n\tBB #%d", loc->bb->index);
3851 fprintf (file, "\n\tEDGE %d->%d", loc->e->src->index,
3852 loc->e->dest->index);
3853 dump_edge_info (file, loc->e, 0);
3855 fprintf (file, "\n\tPREDICATE: ");
3856 print_generic_expr (file, name, 0);
3857 fprintf (file, " %s ", tree_code_name[(int)loc->comp_code]);
3858 print_generic_expr (file, loc->val, 0);
3859 fprintf (file, "\n\n");
3863 fprintf (file, "\n");
3867 /* Dump all the registered assertions for NAME to stderr. */
3870 debug_asserts_for (tree name)
3872 dump_asserts_for (stderr, name);
3876 /* Dump all the registered assertions for all the names to FILE. */
3879 dump_all_asserts (FILE *file)
3884 fprintf (file, "\nASSERT_EXPRs to be inserted\n\n");
3885 EXECUTE_IF_SET_IN_BITMAP (need_assert_for, 0, i, bi)
3886 dump_asserts_for (file, ssa_name (i));
3887 fprintf (file, "\n");
3891 /* Dump all the registered assertions for all the names to stderr. */
3894 debug_all_asserts (void)
3896 dump_all_asserts (stderr);
3900 /* If NAME doesn't have an ASSERT_EXPR registered for asserting
3901 'EXPR COMP_CODE VAL' at a location that dominates block BB or
3902 E->DEST, then register this location as a possible insertion point
3903 for ASSERT_EXPR <NAME, EXPR COMP_CODE VAL>.
3905 BB, E and SI provide the exact insertion point for the new
3906 ASSERT_EXPR. If BB is NULL, then the ASSERT_EXPR is to be inserted
3907 on edge E. Otherwise, if E is NULL, the ASSERT_EXPR is inserted on
3908 BB. If SI points to a COND_EXPR or a SWITCH_EXPR statement, then E
3909 must not be NULL. */
3912 register_new_assert_for (tree name, tree expr,
3913 enum tree_code comp_code,
3917 gimple_stmt_iterator si)
3919 assert_locus_t n, loc, last_loc;
3920 basic_block dest_bb;
3922 #if defined ENABLE_CHECKING
3923 gcc_assert (bb == NULL || e == NULL);
3926 gcc_assert (gimple_code (gsi_stmt (si)) != GIMPLE_COND
3927 && gimple_code (gsi_stmt (si)) != GIMPLE_SWITCH);
3930 /* Never build an assert comparing against an integer constant with
3931 TREE_OVERFLOW set. This confuses our undefined overflow warning
3933 if (TREE_CODE (val) == INTEGER_CST
3934 && TREE_OVERFLOW (val))
3935 val = build_int_cst_wide (TREE_TYPE (val),
3936 TREE_INT_CST_LOW (val), TREE_INT_CST_HIGH (val));
3938 /* The new assertion A will be inserted at BB or E. We need to
3939 determine if the new location is dominated by a previously
3940 registered location for A. If we are doing an edge insertion,
3941 assume that A will be inserted at E->DEST. Note that this is not
3944 If E is a critical edge, it will be split. But even if E is
3945 split, the new block will dominate the same set of blocks that
3948 The reverse, however, is not true, blocks dominated by E->DEST
3949 will not be dominated by the new block created to split E. So,
3950 if the insertion location is on a critical edge, we will not use
3951 the new location to move another assertion previously registered
3952 at a block dominated by E->DEST. */
3953 dest_bb = (bb) ? bb : e->dest;
3955 /* If NAME already has an ASSERT_EXPR registered for COMP_CODE and
3956 VAL at a block dominating DEST_BB, then we don't need to insert a new
3957 one. Similarly, if the same assertion already exists at a block
3958 dominated by DEST_BB and the new location is not on a critical
3959 edge, then update the existing location for the assertion (i.e.,
3960 move the assertion up in the dominance tree).
3962 Note, this is implemented as a simple linked list because there
3963 should not be more than a handful of assertions registered per
3964 name. If this becomes a performance problem, a table hashed by
3965 COMP_CODE and VAL could be implemented. */
3966 loc = asserts_for[SSA_NAME_VERSION (name)];
3970 if (loc->comp_code == comp_code
3972 || operand_equal_p (loc->val, val, 0))
3973 && (loc->expr == expr
3974 || operand_equal_p (loc->expr, expr, 0)))
3976 /* If the assertion NAME COMP_CODE VAL has already been
3977 registered at a basic block that dominates DEST_BB, then
3978 we don't need to insert the same assertion again. Note
3979 that we don't check strict dominance here to avoid
3980 replicating the same assertion inside the same basic
3981 block more than once (e.g., when a pointer is
3982 dereferenced several times inside a block).
3984 An exception to this rule are edge insertions. If the
3985 new assertion is to be inserted on edge E, then it will
3986 dominate all the other insertions that we may want to
3987 insert in DEST_BB. So, if we are doing an edge
3988 insertion, don't do this dominance check. */
3990 && dominated_by_p (CDI_DOMINATORS, dest_bb, loc->bb))
3993 /* Otherwise, if E is not a critical edge and DEST_BB
3994 dominates the existing location for the assertion, move
3995 the assertion up in the dominance tree by updating its
3996 location information. */
3997 if ((e == NULL || !EDGE_CRITICAL_P (e))
3998 && dominated_by_p (CDI_DOMINATORS, loc->bb, dest_bb))
4007 /* Update the last node of the list and move to the next one. */
4012 /* If we didn't find an assertion already registered for
4013 NAME COMP_CODE VAL, add a new one at the end of the list of
4014 assertions associated with NAME. */
4015 n = XNEW (struct assert_locus_d);
4019 n->comp_code = comp_code;
4027 asserts_for[SSA_NAME_VERSION (name)] = n;
4029 bitmap_set_bit (need_assert_for, SSA_NAME_VERSION (name));
4032 /* (COND_OP0 COND_CODE COND_OP1) is a predicate which uses NAME.
4033 Extract a suitable test code and value and store them into *CODE_P and
4034 *VAL_P so the predicate is normalized to NAME *CODE_P *VAL_P.
4036 If no extraction was possible, return FALSE, otherwise return TRUE.
4038 If INVERT is true, then we invert the result stored into *CODE_P. */
4041 extract_code_and_val_from_cond_with_ops (tree name, enum tree_code cond_code,
4042 tree cond_op0, tree cond_op1,
4043 bool invert, enum tree_code *code_p,
4046 enum tree_code comp_code;
4049 /* Otherwise, we have a comparison of the form NAME COMP VAL
4050 or VAL COMP NAME. */
4051 if (name == cond_op1)
4053 /* If the predicate is of the form VAL COMP NAME, flip
4054 COMP around because we need to register NAME as the
4055 first operand in the predicate. */
4056 comp_code = swap_tree_comparison (cond_code);
4061 /* The comparison is of the form NAME COMP VAL, so the
4062 comparison code remains unchanged. */
4063 comp_code = cond_code;
4067 /* Invert the comparison code as necessary. */
4069 comp_code = invert_tree_comparison (comp_code, 0);
4071 /* VRP does not handle float types. */
4072 if (SCALAR_FLOAT_TYPE_P (TREE_TYPE (val)))
4075 /* Do not register always-false predicates.
4076 FIXME: this works around a limitation in fold() when dealing with
4077 enumerations. Given 'enum { N1, N2 } x;', fold will not
4078 fold 'if (x > N2)' to 'if (0)'. */
4079 if ((comp_code == GT_EXPR || comp_code == LT_EXPR)
4080 && INTEGRAL_TYPE_P (TREE_TYPE (val)))
4082 tree min = TYPE_MIN_VALUE (TREE_TYPE (val));
4083 tree max = TYPE_MAX_VALUE (TREE_TYPE (val));
4085 if (comp_code == GT_EXPR
4087 || compare_values (val, max) == 0))
4090 if (comp_code == LT_EXPR
4092 || compare_values (val, min) == 0))
4095 *code_p = comp_code;
4100 /* Try to register an edge assertion for SSA name NAME on edge E for
4101 the condition COND contributing to the conditional jump pointed to by BSI.
4102 Invert the condition COND if INVERT is true.
4103 Return true if an assertion for NAME could be registered. */
4106 register_edge_assert_for_2 (tree name, edge e, gimple_stmt_iterator bsi,
4107 enum tree_code cond_code,
4108 tree cond_op0, tree cond_op1, bool invert)
4111 enum tree_code comp_code;
4112 bool retval = false;
4114 if (!extract_code_and_val_from_cond_with_ops (name, cond_code,
4117 invert, &comp_code, &val))
4120 /* Only register an ASSERT_EXPR if NAME was found in the sub-graph
4121 reachable from E. */
4122 if (live_on_edge (e, name)
4123 && !has_single_use (name))
4125 register_new_assert_for (name, name, comp_code, val, NULL, e, bsi);
4129 /* In the case of NAME <= CST and NAME being defined as
4130 NAME = (unsigned) NAME2 + CST2 we can assert NAME2 >= -CST2
4131 and NAME2 <= CST - CST2. We can do the same for NAME > CST.
4132 This catches range and anti-range tests. */
4133 if ((comp_code == LE_EXPR
4134 || comp_code == GT_EXPR)
4135 && TREE_CODE (val) == INTEGER_CST
4136 && TYPE_UNSIGNED (TREE_TYPE (val)))
4138 gimple def_stmt = SSA_NAME_DEF_STMT (name);
4139 tree cst2 = NULL_TREE, name2 = NULL_TREE, name3 = NULL_TREE;
4141 /* Extract CST2 from the (optional) addition. */
4142 if (is_gimple_assign (def_stmt)
4143 && gimple_assign_rhs_code (def_stmt) == PLUS_EXPR)
4145 name2 = gimple_assign_rhs1 (def_stmt);
4146 cst2 = gimple_assign_rhs2 (def_stmt);
4147 if (TREE_CODE (name2) == SSA_NAME
4148 && TREE_CODE (cst2) == INTEGER_CST)
4149 def_stmt = SSA_NAME_DEF_STMT (name2);
4152 /* Extract NAME2 from the (optional) sign-changing cast. */
4153 if (gimple_assign_cast_p (def_stmt))
4155 if (CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (def_stmt))
4156 && ! TYPE_UNSIGNED (TREE_TYPE (gimple_assign_rhs1 (def_stmt)))
4157 && (TYPE_PRECISION (gimple_expr_type (def_stmt))
4158 == TYPE_PRECISION (TREE_TYPE (gimple_assign_rhs1 (def_stmt)))))
4159 name3 = gimple_assign_rhs1 (def_stmt);
4162 /* If name3 is used later, create an ASSERT_EXPR for it. */
4163 if (name3 != NULL_TREE
4164 && TREE_CODE (name3) == SSA_NAME
4165 && (cst2 == NULL_TREE
4166 || TREE_CODE (cst2) == INTEGER_CST)
4167 && INTEGRAL_TYPE_P (TREE_TYPE (name3))
4168 && live_on_edge (e, name3)
4169 && !has_single_use (name3))
4173 /* Build an expression for the range test. */
4174 tmp = build1 (NOP_EXPR, TREE_TYPE (name), name3);
4175 if (cst2 != NULL_TREE)
4176 tmp = build2 (PLUS_EXPR, TREE_TYPE (name), tmp, cst2);
4180 fprintf (dump_file, "Adding assert for ");
4181 print_generic_expr (dump_file, name3, 0);
4182 fprintf (dump_file, " from ");
4183 print_generic_expr (dump_file, tmp, 0);
4184 fprintf (dump_file, "\n");
4187 register_new_assert_for (name3, tmp, comp_code, val, NULL, e, bsi);
4192 /* If name2 is used later, create an ASSERT_EXPR for it. */
4193 if (name2 != NULL_TREE
4194 && TREE_CODE (name2) == SSA_NAME
4195 && TREE_CODE (cst2) == INTEGER_CST
4196 && INTEGRAL_TYPE_P (TREE_TYPE (name2))
4197 && live_on_edge (e, name2)
4198 && !has_single_use (name2))
4202 /* Build an expression for the range test. */
4204 if (TREE_TYPE (name) != TREE_TYPE (name2))
4205 tmp = build1 (NOP_EXPR, TREE_TYPE (name), tmp);
4206 if (cst2 != NULL_TREE)
4207 tmp = build2 (PLUS_EXPR, TREE_TYPE (name), tmp, cst2);
4211 fprintf (dump_file, "Adding assert for ");
4212 print_generic_expr (dump_file, name2, 0);
4213 fprintf (dump_file, " from ");
4214 print_generic_expr (dump_file, tmp, 0);
4215 fprintf (dump_file, "\n");
4218 register_new_assert_for (name2, tmp, comp_code, val, NULL, e, bsi);
4227 /* OP is an operand of a truth value expression which is known to have
4228 a particular value. Register any asserts for OP and for any
4229 operands in OP's defining statement.
4231 If CODE is EQ_EXPR, then we want to register OP is zero (false),
4232 if CODE is NE_EXPR, then we want to register OP is nonzero (true). */
4235 register_edge_assert_for_1 (tree op, enum tree_code code,
4236 edge e, gimple_stmt_iterator bsi)
4238 bool retval = false;
4241 enum tree_code rhs_code;
4243 /* We only care about SSA_NAMEs. */
4244 if (TREE_CODE (op) != SSA_NAME)
4247 /* We know that OP will have a zero or nonzero value. If OP is used
4248 more than once go ahead and register an assert for OP.
4250 The FOUND_IN_SUBGRAPH support is not helpful in this situation as
4251 it will always be set for OP (because OP is used in a COND_EXPR in
4253 if (!has_single_use (op))
4255 val = build_int_cst (TREE_TYPE (op), 0);
4256 register_new_assert_for (op, op, code, val, NULL, e, bsi);
4260 /* Now look at how OP is set. If it's set from a comparison,
4261 a truth operation or some bit operations, then we may be able
4262 to register information about the operands of that assignment. */
4263 op_def = SSA_NAME_DEF_STMT (op);
4264 if (gimple_code (op_def) != GIMPLE_ASSIGN)
4267 rhs_code = gimple_assign_rhs_code (op_def);
4269 if (TREE_CODE_CLASS (rhs_code) == tcc_comparison)
4271 bool invert = (code == EQ_EXPR ? true : false);
4272 tree op0 = gimple_assign_rhs1 (op_def);
4273 tree op1 = gimple_assign_rhs2 (op_def);
4275 if (TREE_CODE (op0) == SSA_NAME)
4276 retval |= register_edge_assert_for_2 (op0, e, bsi, rhs_code, op0, op1,
4278 if (TREE_CODE (op1) == SSA_NAME)
4279 retval |= register_edge_assert_for_2 (op1, e, bsi, rhs_code, op0, op1,
4282 else if ((code == NE_EXPR
4283 && (gimple_assign_rhs_code (op_def) == TRUTH_AND_EXPR
4284 || gimple_assign_rhs_code (op_def) == BIT_AND_EXPR))
4286 && (gimple_assign_rhs_code (op_def) == TRUTH_OR_EXPR
4287 || gimple_assign_rhs_code (op_def) == BIT_IOR_EXPR)))
4289 /* Recurse on each operand. */
4290 retval |= register_edge_assert_for_1 (gimple_assign_rhs1 (op_def),
4292 retval |= register_edge_assert_for_1 (gimple_assign_rhs2 (op_def),
4295 else if (gimple_assign_rhs_code (op_def) == TRUTH_NOT_EXPR)
4297 /* Recurse, flipping CODE. */
4298 code = invert_tree_comparison (code, false);
4299 retval |= register_edge_assert_for_1 (gimple_assign_rhs1 (op_def),
4302 else if (gimple_assign_rhs_code (op_def) == SSA_NAME)
4304 /* Recurse through the copy. */
4305 retval |= register_edge_assert_for_1 (gimple_assign_rhs1 (op_def),
4308 else if (CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (op_def)))
4310 /* Recurse through the type conversion. */
4311 retval |= register_edge_assert_for_1 (gimple_assign_rhs1 (op_def),
4318 /* Try to register an edge assertion for SSA name NAME on edge E for
4319 the condition COND contributing to the conditional jump pointed to by SI.
4320 Return true if an assertion for NAME could be registered. */
4323 register_edge_assert_for (tree name, edge e, gimple_stmt_iterator si,
4324 enum tree_code cond_code, tree cond_op0,
4328 enum tree_code comp_code;
4329 bool retval = false;
4330 bool is_else_edge = (e->flags & EDGE_FALSE_VALUE) != 0;
4332 /* Do not attempt to infer anything in names that flow through
4334 if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (name))
4337 if (!extract_code_and_val_from_cond_with_ops (name, cond_code,
4343 /* Register ASSERT_EXPRs for name. */
4344 retval |= register_edge_assert_for_2 (name, e, si, cond_code, cond_op0,
4345 cond_op1, is_else_edge);
4348 /* If COND is effectively an equality test of an SSA_NAME against
4349 the value zero or one, then we may be able to assert values
4350 for SSA_NAMEs which flow into COND. */
4352 /* In the case of NAME == 1 or NAME != 0, for TRUTH_AND_EXPR defining
4353 statement of NAME we can assert both operands of the TRUTH_AND_EXPR
4354 have nonzero value. */
4355 if (((comp_code == EQ_EXPR && integer_onep (val))
4356 || (comp_code == NE_EXPR && integer_zerop (val))))
4358 gimple def_stmt = SSA_NAME_DEF_STMT (name);
4360 if (is_gimple_assign (def_stmt)
4361 && (gimple_assign_rhs_code (def_stmt) == TRUTH_AND_EXPR
4362 || gimple_assign_rhs_code (def_stmt) == BIT_AND_EXPR))
4364 tree op0 = gimple_assign_rhs1 (def_stmt);
4365 tree op1 = gimple_assign_rhs2 (def_stmt);
4366 retval |= register_edge_assert_for_1 (op0, NE_EXPR, e, si);
4367 retval |= register_edge_assert_for_1 (op1, NE_EXPR, e, si);
4371 /* In the case of NAME == 0 or NAME != 1, for TRUTH_OR_EXPR defining
4372 statement of NAME we can assert both operands of the TRUTH_OR_EXPR
4374 if (((comp_code == EQ_EXPR && integer_zerop (val))
4375 || (comp_code == NE_EXPR && integer_onep (val))))
4377 gimple def_stmt = SSA_NAME_DEF_STMT (name);
4379 if (is_gimple_assign (def_stmt)
4380 && (gimple_assign_rhs_code (def_stmt) == TRUTH_OR_EXPR
4381 /* For BIT_IOR_EXPR only if NAME == 0 both operands have
4382 necessarily zero value. */
4383 || (comp_code == EQ_EXPR
4384 && (gimple_assign_rhs_code (def_stmt) == BIT_IOR_EXPR))))
4386 tree op0 = gimple_assign_rhs1 (def_stmt);
4387 tree op1 = gimple_assign_rhs2 (def_stmt);
4388 retval |= register_edge_assert_for_1 (op0, EQ_EXPR, e, si);
4389 retval |= register_edge_assert_for_1 (op1, EQ_EXPR, e, si);
4397 /* Determine whether the outgoing edges of BB should receive an
4398 ASSERT_EXPR for each of the operands of BB's LAST statement.
4399 The last statement of BB must be a COND_EXPR.
4401 If any of the sub-graphs rooted at BB have an interesting use of
4402 the predicate operands, an assert location node is added to the
4403 list of assertions for the corresponding operands. */
4406 find_conditional_asserts (basic_block bb, gimple last)
4409 gimple_stmt_iterator bsi;
4415 need_assert = false;
4416 bsi = gsi_for_stmt (last);
4418 /* Look for uses of the operands in each of the sub-graphs
4419 rooted at BB. We need to check each of the outgoing edges
4420 separately, so that we know what kind of ASSERT_EXPR to
4422 FOR_EACH_EDGE (e, ei, bb->succs)
4427 /* Register the necessary assertions for each operand in the
4428 conditional predicate. */
4429 FOR_EACH_SSA_TREE_OPERAND (op, last, iter, SSA_OP_USE)
4431 need_assert |= register_edge_assert_for (op, e, bsi,
4432 gimple_cond_code (last),
4433 gimple_cond_lhs (last),
4434 gimple_cond_rhs (last));
4441 /* Compare two case labels sorting first by the destination label uid
4442 and then by the case value. */
4445 compare_case_labels (const void *p1, const void *p2)
4447 const_tree const case1 = *(const_tree const*)p1;
4448 const_tree const case2 = *(const_tree const*)p2;
4449 unsigned int uid1 = DECL_UID (CASE_LABEL (case1));
4450 unsigned int uid2 = DECL_UID (CASE_LABEL (case2));
4454 else if (uid1 == uid2)
4456 /* Make sure the default label is first in a group. */
4457 if (!CASE_LOW (case1))
4459 else if (!CASE_LOW (case2))
4462 return tree_int_cst_compare (CASE_LOW (case1), CASE_LOW (case2));
4468 /* Determine whether the outgoing edges of BB should receive an
4469 ASSERT_EXPR for each of the operands of BB's LAST statement.
4470 The last statement of BB must be a SWITCH_EXPR.
4472 If any of the sub-graphs rooted at BB have an interesting use of
4473 the predicate operands, an assert location node is added to the
4474 list of assertions for the corresponding operands. */
4477 find_switch_asserts (basic_block bb, gimple last)
4480 gimple_stmt_iterator bsi;
4484 size_t n = gimple_switch_num_labels(last);
4485 #if GCC_VERSION >= 4000
4488 /* Work around GCC 3.4 bug (PR 37086). */
4489 volatile unsigned int idx;
4492 need_assert = false;
4493 bsi = gsi_for_stmt (last);
4494 op = gimple_switch_index (last);
4495 if (TREE_CODE (op) != SSA_NAME)
4498 /* Build a vector of case labels sorted by destination label. */
4499 vec2 = make_tree_vec (n);
4500 for (idx = 0; idx < n; ++idx)
4501 TREE_VEC_ELT (vec2, idx) = gimple_switch_label (last, idx);
4502 qsort (&TREE_VEC_ELT (vec2, 0), n, sizeof (tree), compare_case_labels);
4504 for (idx = 0; idx < n; ++idx)
4507 tree cl = TREE_VEC_ELT (vec2, idx);
4509 min = CASE_LOW (cl);
4510 max = CASE_HIGH (cl);
4512 /* If there are multiple case labels with the same destination
4513 we need to combine them to a single value range for the edge. */
4515 && CASE_LABEL (cl) == CASE_LABEL (TREE_VEC_ELT (vec2, idx + 1)))
4517 /* Skip labels until the last of the group. */
4521 && CASE_LABEL (cl) == CASE_LABEL (TREE_VEC_ELT (vec2, idx)));
4524 /* Pick up the maximum of the case label range. */
4525 if (CASE_HIGH (TREE_VEC_ELT (vec2, idx)))
4526 max = CASE_HIGH (TREE_VEC_ELT (vec2, idx));
4528 max = CASE_LOW (TREE_VEC_ELT (vec2, idx));
4531 /* Nothing to do if the range includes the default label until we
4532 can register anti-ranges. */
4533 if (min == NULL_TREE)
4536 /* Find the edge to register the assert expr on. */
4537 e = find_edge (bb, label_to_block (CASE_LABEL (cl)));
4539 /* Register the necessary assertions for the operand in the
4541 need_assert |= register_edge_assert_for (op, e, bsi,
4542 max ? GE_EXPR : EQ_EXPR,
4544 fold_convert (TREE_TYPE (op),
4548 need_assert |= register_edge_assert_for (op, e, bsi, LE_EXPR,
4550 fold_convert (TREE_TYPE (op),
4559 /* Traverse all the statements in block BB looking for statements that
4560 may generate useful assertions for the SSA names in their operand.
4561 If a statement produces a useful assertion A for name N_i, then the
4562 list of assertions already generated for N_i is scanned to
4563 determine if A is actually needed.
4565 If N_i already had the assertion A at a location dominating the
4566 current location, then nothing needs to be done. Otherwise, the
4567 new location for A is recorded instead.
4569 1- For every statement S in BB, all the variables used by S are
4570 added to bitmap FOUND_IN_SUBGRAPH.
4572 2- If statement S uses an operand N in a way that exposes a known
4573 value range for N, then if N was not already generated by an
4574 ASSERT_EXPR, create a new assert location for N. For instance,
4575 if N is a pointer and the statement dereferences it, we can
4576 assume that N is not NULL.
4578 3- COND_EXPRs are a special case of #2. We can derive range
4579 information from the predicate but need to insert different
4580 ASSERT_EXPRs for each of the sub-graphs rooted at the
4581 conditional block. If the last statement of BB is a conditional
4582 expression of the form 'X op Y', then
4584 a) Remove X and Y from the set FOUND_IN_SUBGRAPH.
4586 b) If the conditional is the only entry point to the sub-graph
4587 corresponding to the THEN_CLAUSE, recurse into it. On
4588 return, if X and/or Y are marked in FOUND_IN_SUBGRAPH, then
4589 an ASSERT_EXPR is added for the corresponding variable.
4591 c) Repeat step (b) on the ELSE_CLAUSE.
4593 d) Mark X and Y in FOUND_IN_SUBGRAPH.
4602 In this case, an assertion on the THEN clause is useful to
4603 determine that 'a' is always 9 on that edge. However, an assertion
4604 on the ELSE clause would be unnecessary.
4606 4- If BB does not end in a conditional expression, then we recurse
4607 into BB's dominator children.
4609 At the end of the recursive traversal, every SSA name will have a
4610 list of locations where ASSERT_EXPRs should be added. When a new
4611 location for name N is found, it is registered by calling
4612 register_new_assert_for. That function keeps track of all the
4613 registered assertions to prevent adding unnecessary assertions.
4614 For instance, if a pointer P_4 is dereferenced more than once in a
4615 dominator tree, only the location dominating all the dereference of
4616 P_4 will receive an ASSERT_EXPR.
4618 If this function returns true, then it means that there are names
4619 for which we need to generate ASSERT_EXPRs. Those assertions are
4620 inserted by process_assert_insertions. */
4623 find_assert_locations_1 (basic_block bb, sbitmap live)
4625 gimple_stmt_iterator si;
4630 need_assert = false;
4631 last = last_stmt (bb);
4633 /* If BB's last statement is a conditional statement involving integer
4634 operands, determine if we need to add ASSERT_EXPRs. */
4636 && gimple_code (last) == GIMPLE_COND
4637 && !fp_predicate (last)
4638 && !ZERO_SSA_OPERANDS (last, SSA_OP_USE))
4639 need_assert |= find_conditional_asserts (bb, last);
4641 /* If BB's last statement is a switch statement involving integer
4642 operands, determine if we need to add ASSERT_EXPRs. */
4644 && gimple_code (last) == GIMPLE_SWITCH
4645 && !ZERO_SSA_OPERANDS (last, SSA_OP_USE))
4646 need_assert |= find_switch_asserts (bb, last);
4648 /* Traverse all the statements in BB marking used names and looking
4649 for statements that may infer assertions for their used operands. */
4650 for (si = gsi_start_bb (bb); !gsi_end_p (si); gsi_next (&si))
4656 stmt = gsi_stmt (si);
4658 if (is_gimple_debug (stmt))
4661 /* See if we can derive an assertion for any of STMT's operands. */
4662 FOR_EACH_SSA_TREE_OPERAND (op, stmt, i, SSA_OP_USE)
4665 enum tree_code comp_code;
4667 /* Mark OP in our live bitmap. */
4668 SET_BIT (live, SSA_NAME_VERSION (op));
4670 /* If OP is used in such a way that we can infer a value
4671 range for it, and we don't find a previous assertion for
4672 it, create a new assertion location node for OP. */
4673 if (infer_value_range (stmt, op, &comp_code, &value))
4675 /* If we are able to infer a nonzero value range for OP,
4676 then walk backwards through the use-def chain to see if OP
4677 was set via a typecast.
4679 If so, then we can also infer a nonzero value range
4680 for the operand of the NOP_EXPR. */
4681 if (comp_code == NE_EXPR && integer_zerop (value))
4684 gimple def_stmt = SSA_NAME_DEF_STMT (t);
4686 while (is_gimple_assign (def_stmt)
4687 && gimple_assign_rhs_code (def_stmt) == NOP_EXPR
4689 (gimple_assign_rhs1 (def_stmt)) == SSA_NAME
4691 (TREE_TYPE (gimple_assign_rhs1 (def_stmt))))
4693 t = gimple_assign_rhs1 (def_stmt);
4694 def_stmt = SSA_NAME_DEF_STMT (t);
4696 /* Note we want to register the assert for the
4697 operand of the NOP_EXPR after SI, not after the
4699 if (! has_single_use (t))
4701 register_new_assert_for (t, t, comp_code, value,
4708 /* If OP is used only once, namely in this STMT, don't
4709 bother creating an ASSERT_EXPR for it. Such an
4710 ASSERT_EXPR would do nothing but increase compile time. */
4711 if (!has_single_use (op))
4713 register_new_assert_for (op, op, comp_code, value,
4721 /* Traverse all PHI nodes in BB marking used operands. */
4722 for (si = gsi_start_phis (bb); !gsi_end_p(si); gsi_next (&si))
4724 use_operand_p arg_p;
4726 phi = gsi_stmt (si);
4728 FOR_EACH_PHI_ARG (arg_p, phi, i, SSA_OP_USE)
4730 tree arg = USE_FROM_PTR (arg_p);
4731 if (TREE_CODE (arg) == SSA_NAME)
4732 SET_BIT (live, SSA_NAME_VERSION (arg));
4739 /* Do an RPO walk over the function computing SSA name liveness
4740 on-the-fly and deciding on assert expressions to insert.
4741 Returns true if there are assert expressions to be inserted. */
4744 find_assert_locations (void)
4746 int *rpo = XCNEWVEC (int, last_basic_block + NUM_FIXED_BLOCKS);
4747 int *bb_rpo = XCNEWVEC (int, last_basic_block + NUM_FIXED_BLOCKS);
4748 int *last_rpo = XCNEWVEC (int, last_basic_block + NUM_FIXED_BLOCKS);
4752 live = XCNEWVEC (sbitmap, last_basic_block + NUM_FIXED_BLOCKS);
4753 rpo_cnt = pre_and_rev_post_order_compute (NULL, rpo, false);
4754 for (i = 0; i < rpo_cnt; ++i)
4757 need_asserts = false;
4758 for (i = rpo_cnt-1; i >= 0; --i)
4760 basic_block bb = BASIC_BLOCK (rpo[i]);
4766 live[rpo[i]] = sbitmap_alloc (num_ssa_names);
4767 sbitmap_zero (live[rpo[i]]);
4770 /* Process BB and update the live information with uses in
4772 need_asserts |= find_assert_locations_1 (bb, live[rpo[i]]);
4774 /* Merge liveness into the predecessor blocks and free it. */
4775 if (!sbitmap_empty_p (live[rpo[i]]))
4778 FOR_EACH_EDGE (e, ei, bb->preds)
4780 int pred = e->src->index;
4781 if (e->flags & EDGE_DFS_BACK)
4786 live[pred] = sbitmap_alloc (num_ssa_names);
4787 sbitmap_zero (live[pred]);
4789 sbitmap_a_or_b (live[pred], live[pred], live[rpo[i]]);
4791 if (bb_rpo[pred] < pred_rpo)
4792 pred_rpo = bb_rpo[pred];
4795 /* Record the RPO number of the last visited block that needs
4796 live information from this block. */
4797 last_rpo[rpo[i]] = pred_rpo;
4801 sbitmap_free (live[rpo[i]]);
4802 live[rpo[i]] = NULL;
4805 /* We can free all successors live bitmaps if all their
4806 predecessors have been visited already. */
4807 FOR_EACH_EDGE (e, ei, bb->succs)
4808 if (last_rpo[e->dest->index] == i
4809 && live[e->dest->index])
4811 sbitmap_free (live[e->dest->index]);
4812 live[e->dest->index] = NULL;
4817 XDELETEVEC (bb_rpo);
4818 XDELETEVEC (last_rpo);
4819 for (i = 0; i < last_basic_block + NUM_FIXED_BLOCKS; ++i)
4821 sbitmap_free (live[i]);
4824 return need_asserts;
4827 /* Create an ASSERT_EXPR for NAME and insert it in the location
4828 indicated by LOC. Return true if we made any edge insertions. */
4831 process_assert_insertions_for (tree name, assert_locus_t loc)
4833 /* Build the comparison expression NAME_i COMP_CODE VAL. */
4840 /* If we have X <=> X do not insert an assert expr for that. */
4841 if (loc->expr == loc->val)
4844 cond = build2 (loc->comp_code, boolean_type_node, loc->expr, loc->val);
4845 assert_stmt = build_assert_expr_for (cond, name);
4848 /* We have been asked to insert the assertion on an edge. This
4849 is used only by COND_EXPR and SWITCH_EXPR assertions. */
4850 #if defined ENABLE_CHECKING
4851 gcc_assert (gimple_code (gsi_stmt (loc->si)) == GIMPLE_COND
4852 || gimple_code (gsi_stmt (loc->si)) == GIMPLE_SWITCH);
4855 gsi_insert_on_edge (loc->e, assert_stmt);
4859 /* Otherwise, we can insert right after LOC->SI iff the
4860 statement must not be the last statement in the block. */
4861 stmt = gsi_stmt (loc->si);
4862 if (!stmt_ends_bb_p (stmt))
4864 gsi_insert_after (&loc->si, assert_stmt, GSI_SAME_STMT);
4868 /* If STMT must be the last statement in BB, we can only insert new
4869 assertions on the non-abnormal edge out of BB. Note that since
4870 STMT is not control flow, there may only be one non-abnormal edge
4872 FOR_EACH_EDGE (e, ei, loc->bb->succs)
4873 if (!(e->flags & EDGE_ABNORMAL))
4875 gsi_insert_on_edge (e, assert_stmt);
4883 /* Process all the insertions registered for every name N_i registered
4884 in NEED_ASSERT_FOR. The list of assertions to be inserted are
4885 found in ASSERTS_FOR[i]. */
4888 process_assert_insertions (void)
4892 bool update_edges_p = false;
4893 int num_asserts = 0;
4895 if (dump_file && (dump_flags & TDF_DETAILS))
4896 dump_all_asserts (dump_file);
4898 EXECUTE_IF_SET_IN_BITMAP (need_assert_for, 0, i, bi)
4900 assert_locus_t loc = asserts_for[i];
4905 assert_locus_t next = loc->next;
4906 update_edges_p |= process_assert_insertions_for (ssa_name (i), loc);
4914 gsi_commit_edge_inserts ();
4916 statistics_counter_event (cfun, "Number of ASSERT_EXPR expressions inserted",
4921 /* Traverse the flowgraph looking for conditional jumps to insert range
4922 expressions. These range expressions are meant to provide information
4923 to optimizations that need to reason in terms of value ranges. They
4924 will not be expanded into RTL. For instance, given:
4933 this pass will transform the code into:
4939 x = ASSERT_EXPR <x, x < y>
4944 y = ASSERT_EXPR <y, x <= y>
4948 The idea is that once copy and constant propagation have run, other
4949 optimizations will be able to determine what ranges of values can 'x'
4950 take in different paths of the code, simply by checking the reaching
4951 definition of 'x'. */
4954 insert_range_assertions (void)
4956 need_assert_for = BITMAP_ALLOC (NULL);
4957 asserts_for = XCNEWVEC (assert_locus_t, num_ssa_names);
4959 calculate_dominance_info (CDI_DOMINATORS);
4961 if (find_assert_locations ())
4963 process_assert_insertions ();
4964 update_ssa (TODO_update_ssa_no_phi);
4967 if (dump_file && (dump_flags & TDF_DETAILS))
4969 fprintf (dump_file, "\nSSA form after inserting ASSERT_EXPRs\n");
4970 dump_function_to_file (current_function_decl, dump_file, dump_flags);
4974 BITMAP_FREE (need_assert_for);
4977 /* Checks one ARRAY_REF in REF, located at LOCUS. Ignores flexible arrays
4978 and "struct" hacks. If VRP can determine that the
4979 array subscript is a constant, check if it is outside valid
4980 range. If the array subscript is a RANGE, warn if it is
4981 non-overlapping with valid range.
4982 IGNORE_OFF_BY_ONE is true if the ARRAY_REF is inside a ADDR_EXPR. */
4985 check_array_ref (location_t location, tree ref, bool ignore_off_by_one)
4987 value_range_t* vr = NULL;
4988 tree low_sub, up_sub;
4989 tree low_bound, up_bound = array_ref_up_bound (ref);
4991 low_sub = up_sub = TREE_OPERAND (ref, 1);
4993 if (!up_bound || TREE_NO_WARNING (ref)
4994 || TREE_CODE (up_bound) != INTEGER_CST
4995 /* Can not check flexible arrays. */
4996 || (TYPE_SIZE (TREE_TYPE (ref)) == NULL_TREE
4997 && TYPE_DOMAIN (TREE_TYPE (ref)) != NULL_TREE
4998 && TYPE_MAX_VALUE (TYPE_DOMAIN (TREE_TYPE (ref))) == NULL_TREE)
4999 /* Accesses after the end of arrays of size 0 (gcc
5000 extension) and 1 are likely intentional ("struct
5002 || compare_tree_int (up_bound, 1) <= 0)
5005 low_bound = array_ref_low_bound (ref);
5007 if (TREE_CODE (low_sub) == SSA_NAME)
5009 vr = get_value_range (low_sub);
5010 if (vr->type == VR_RANGE || vr->type == VR_ANTI_RANGE)
5012 low_sub = vr->type == VR_RANGE ? vr->max : vr->min;
5013 up_sub = vr->type == VR_RANGE ? vr->min : vr->max;
5017 if (vr && vr->type == VR_ANTI_RANGE)
5019 if (TREE_CODE (up_sub) == INTEGER_CST
5020 && tree_int_cst_lt (up_bound, up_sub)
5021 && TREE_CODE (low_sub) == INTEGER_CST
5022 && tree_int_cst_lt (low_sub, low_bound))
5024 warning_at (location, OPT_Warray_bounds,
5025 "array subscript is outside array bounds");
5026 TREE_NO_WARNING (ref) = 1;
5029 else if (TREE_CODE (up_sub) == INTEGER_CST
5030 && tree_int_cst_lt (up_bound, up_sub)
5031 && !tree_int_cst_equal (up_bound, up_sub)
5032 && (!ignore_off_by_one
5033 || !tree_int_cst_equal (int_const_binop (PLUS_EXPR,
5039 warning_at (location, OPT_Warray_bounds,
5040 "array subscript is above array bounds");
5041 TREE_NO_WARNING (ref) = 1;
5043 else if (TREE_CODE (low_sub) == INTEGER_CST
5044 && tree_int_cst_lt (low_sub, low_bound))
5046 warning_at (location, OPT_Warray_bounds,
5047 "array subscript is below array bounds");
5048 TREE_NO_WARNING (ref) = 1;
5052 /* Searches if the expr T, located at LOCATION computes
5053 address of an ARRAY_REF, and call check_array_ref on it. */
5056 search_for_addr_array (tree t, location_t location)
5058 while (TREE_CODE (t) == SSA_NAME)
5060 gimple g = SSA_NAME_DEF_STMT (t);
5062 if (gimple_code (g) != GIMPLE_ASSIGN)
5065 if (get_gimple_rhs_class (gimple_assign_rhs_code (g))
5066 != GIMPLE_SINGLE_RHS)
5069 t = gimple_assign_rhs1 (g);
5073 /* We are only interested in addresses of ARRAY_REF's. */
5074 if (TREE_CODE (t) != ADDR_EXPR)
5077 /* Check each ARRAY_REFs in the reference chain. */
5080 if (TREE_CODE (t) == ARRAY_REF)
5081 check_array_ref (location, t, true /*ignore_off_by_one*/);
5083 t = TREE_OPERAND (t, 0);
5085 while (handled_component_p (t));
5088 /* walk_tree() callback that checks if *TP is
5089 an ARRAY_REF inside an ADDR_EXPR (in which an array
5090 subscript one outside the valid range is allowed). Call
5091 check_array_ref for each ARRAY_REF found. The location is
5095 check_array_bounds (tree *tp, int *walk_subtree, void *data)
5098 struct walk_stmt_info *wi = (struct walk_stmt_info *) data;
5099 location_t location;
5101 if (EXPR_HAS_LOCATION (t))
5102 location = EXPR_LOCATION (t);
5105 location_t *locp = (location_t *) wi->info;
5109 *walk_subtree = TRUE;
5111 if (TREE_CODE (t) == ARRAY_REF)
5112 check_array_ref (location, t, false /*ignore_off_by_one*/);
5114 if (TREE_CODE (t) == INDIRECT_REF
5115 || (TREE_CODE (t) == RETURN_EXPR && TREE_OPERAND (t, 0)))
5116 search_for_addr_array (TREE_OPERAND (t, 0), location);
5118 if (TREE_CODE (t) == ADDR_EXPR)
5119 *walk_subtree = FALSE;
5124 /* Walk over all statements of all reachable BBs and call check_array_bounds
5128 check_all_array_refs (void)
5131 gimple_stmt_iterator si;
5137 bool executable = false;
5139 /* Skip blocks that were found to be unreachable. */
5140 FOR_EACH_EDGE (e, ei, bb->preds)
5141 executable |= !!(e->flags & EDGE_EXECUTABLE);
5145 for (si = gsi_start_bb (bb); !gsi_end_p (si); gsi_next (&si))
5147 gimple stmt = gsi_stmt (si);
5148 struct walk_stmt_info wi;
5149 if (!gimple_has_location (stmt))
5152 if (is_gimple_call (stmt))
5155 size_t n = gimple_call_num_args (stmt);
5156 for (i = 0; i < n; i++)
5158 tree arg = gimple_call_arg (stmt, i);
5159 search_for_addr_array (arg, gimple_location (stmt));
5164 memset (&wi, 0, sizeof (wi));
5165 wi.info = CONST_CAST (void *, (const void *)
5166 gimple_location_ptr (stmt));
5168 walk_gimple_op (gsi_stmt (si),
5176 /* Convert range assertion expressions into the implied copies and
5177 copy propagate away the copies. Doing the trivial copy propagation
5178 here avoids the need to run the full copy propagation pass after
5181 FIXME, this will eventually lead to copy propagation removing the
5182 names that had useful range information attached to them. For
5183 instance, if we had the assertion N_i = ASSERT_EXPR <N_j, N_j > 3>,
5184 then N_i will have the range [3, +INF].
5186 However, by converting the assertion into the implied copy
5187 operation N_i = N_j, we will then copy-propagate N_j into the uses
5188 of N_i and lose the range information. We may want to hold on to
5189 ASSERT_EXPRs a little while longer as the ranges could be used in
5190 things like jump threading.
5192 The problem with keeping ASSERT_EXPRs around is that passes after
5193 VRP need to handle them appropriately.
5195 Another approach would be to make the range information a first
5196 class property of the SSA_NAME so that it can be queried from
5197 any pass. This is made somewhat more complex by the need for
5198 multiple ranges to be associated with one SSA_NAME. */
5201 remove_range_assertions (void)
5204 gimple_stmt_iterator si;
5206 /* Note that the BSI iterator bump happens at the bottom of the
5207 loop and no bump is necessary if we're removing the statement
5208 referenced by the current BSI. */
5210 for (si = gsi_start_bb (bb); !gsi_end_p (si);)
5212 gimple stmt = gsi_stmt (si);
5215 if (is_gimple_assign (stmt)
5216 && gimple_assign_rhs_code (stmt) == ASSERT_EXPR)
5218 tree rhs = gimple_assign_rhs1 (stmt);
5220 tree cond = fold (ASSERT_EXPR_COND (rhs));
5221 use_operand_p use_p;
5222 imm_use_iterator iter;
5224 gcc_assert (cond != boolean_false_node);
5226 /* Propagate the RHS into every use of the LHS. */
5227 var = ASSERT_EXPR_VAR (rhs);
5228 FOR_EACH_IMM_USE_STMT (use_stmt, iter,
5229 gimple_assign_lhs (stmt))
5230 FOR_EACH_IMM_USE_ON_STMT (use_p, iter)
5232 SET_USE (use_p, var);
5233 gcc_assert (TREE_CODE (var) == SSA_NAME);
5236 /* And finally, remove the copy, it is not needed. */
5237 gsi_remove (&si, true);
5238 release_defs (stmt);
5246 /* Return true if STMT is interesting for VRP. */
5249 stmt_interesting_for_vrp (gimple stmt)
5251 if (gimple_code (stmt) == GIMPLE_PHI
5252 && is_gimple_reg (gimple_phi_result (stmt))
5253 && (INTEGRAL_TYPE_P (TREE_TYPE (gimple_phi_result (stmt)))
5254 || POINTER_TYPE_P (TREE_TYPE (gimple_phi_result (stmt)))))
5256 else if (is_gimple_assign (stmt) || is_gimple_call (stmt))
5258 tree lhs = gimple_get_lhs (stmt);
5260 /* In general, assignments with virtual operands are not useful
5261 for deriving ranges, with the obvious exception of calls to
5262 builtin functions. */
5263 if (lhs && TREE_CODE (lhs) == SSA_NAME
5264 && (INTEGRAL_TYPE_P (TREE_TYPE (lhs))
5265 || POINTER_TYPE_P (TREE_TYPE (lhs)))
5266 && ((is_gimple_call (stmt)
5267 && gimple_call_fndecl (stmt) != NULL_TREE
5268 && DECL_IS_BUILTIN (gimple_call_fndecl (stmt)))
5269 || !gimple_vuse (stmt)))
5272 else if (gimple_code (stmt) == GIMPLE_COND
5273 || gimple_code (stmt) == GIMPLE_SWITCH)
5280 /* Initialize local data structures for VRP. */
5283 vrp_initialize (void)
5287 vr_value = XCNEWVEC (value_range_t *, num_ssa_names);
5288 vr_phi_edge_counts = XCNEWVEC (int, num_ssa_names);
5292 gimple_stmt_iterator si;
5294 for (si = gsi_start_phis (bb); !gsi_end_p (si); gsi_next (&si))
5296 gimple phi = gsi_stmt (si);
5297 if (!stmt_interesting_for_vrp (phi))
5299 tree lhs = PHI_RESULT (phi);
5300 set_value_range_to_varying (get_value_range (lhs));
5301 prop_set_simulate_again (phi, false);
5304 prop_set_simulate_again (phi, true);
5307 for (si = gsi_start_bb (bb); !gsi_end_p (si); gsi_next (&si))
5309 gimple stmt = gsi_stmt (si);
5311 /* If the statement is a control insn, then we do not
5312 want to avoid simulating the statement once. Failure
5313 to do so means that those edges will never get added. */
5314 if (stmt_ends_bb_p (stmt))
5315 prop_set_simulate_again (stmt, true);
5316 else if (!stmt_interesting_for_vrp (stmt))
5320 FOR_EACH_SSA_TREE_OPERAND (def, stmt, i, SSA_OP_DEF)
5321 set_value_range_to_varying (get_value_range (def));
5322 prop_set_simulate_again (stmt, false);
5325 prop_set_simulate_again (stmt, true);
5331 /* Visit assignment STMT. If it produces an interesting range, record
5332 the SSA name in *OUTPUT_P. */
5334 static enum ssa_prop_result
5335 vrp_visit_assignment_or_call (gimple stmt, tree *output_p)
5339 enum gimple_code code = gimple_code (stmt);
5340 lhs = gimple_get_lhs (stmt);
5342 /* We only keep track of ranges in integral and pointer types. */
5343 if (TREE_CODE (lhs) == SSA_NAME
5344 && ((INTEGRAL_TYPE_P (TREE_TYPE (lhs))
5345 /* It is valid to have NULL MIN/MAX values on a type. See
5346 build_range_type. */
5347 && TYPE_MIN_VALUE (TREE_TYPE (lhs))
5348 && TYPE_MAX_VALUE (TREE_TYPE (lhs)))
5349 || POINTER_TYPE_P (TREE_TYPE (lhs))))
5351 value_range_t new_vr = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
5353 if (code == GIMPLE_CALL)
5354 extract_range_basic (&new_vr, stmt);
5356 extract_range_from_assignment (&new_vr, stmt);
5358 if (update_value_range (lhs, &new_vr))
5362 if (dump_file && (dump_flags & TDF_DETAILS))
5364 fprintf (dump_file, "Found new range for ");
5365 print_generic_expr (dump_file, lhs, 0);
5366 fprintf (dump_file, ": ");
5367 dump_value_range (dump_file, &new_vr);
5368 fprintf (dump_file, "\n\n");
5371 if (new_vr.type == VR_VARYING)
5372 return SSA_PROP_VARYING;
5374 return SSA_PROP_INTERESTING;
5377 return SSA_PROP_NOT_INTERESTING;
5380 /* Every other statement produces no useful ranges. */
5381 FOR_EACH_SSA_TREE_OPERAND (def, stmt, iter, SSA_OP_DEF)
5382 set_value_range_to_varying (get_value_range (def));
5384 return SSA_PROP_VARYING;
5387 /* Helper that gets the value range of the SSA_NAME with version I
5388 or a symbolic range containing the SSA_NAME only if the value range
5389 is varying or undefined. */
5391 static inline value_range_t
5392 get_vr_for_comparison (int i)
5394 value_range_t vr = *(vr_value[i]);
5396 /* If name N_i does not have a valid range, use N_i as its own
5397 range. This allows us to compare against names that may
5398 have N_i in their ranges. */
5399 if (vr.type == VR_VARYING || vr.type == VR_UNDEFINED)
5402 vr.min = ssa_name (i);
5403 vr.max = ssa_name (i);
5409 /* Compare all the value ranges for names equivalent to VAR with VAL
5410 using comparison code COMP. Return the same value returned by
5411 compare_range_with_value, including the setting of
5412 *STRICT_OVERFLOW_P. */
5415 compare_name_with_value (enum tree_code comp, tree var, tree val,
5416 bool *strict_overflow_p)
5422 int used_strict_overflow;
5424 value_range_t equiv_vr;
5426 /* Get the set of equivalences for VAR. */
5427 e = get_value_range (var)->equiv;
5429 /* Start at -1. Set it to 0 if we do a comparison without relying
5430 on overflow, or 1 if all comparisons rely on overflow. */
5431 used_strict_overflow = -1;
5433 /* Compare vars' value range with val. */
5434 equiv_vr = get_vr_for_comparison (SSA_NAME_VERSION (var));
5436 retval = compare_range_with_value (comp, &equiv_vr, val, &sop);
5438 used_strict_overflow = sop ? 1 : 0;
5440 /* If the equiv set is empty we have done all work we need to do. */
5444 && used_strict_overflow > 0)
5445 *strict_overflow_p = true;
5449 EXECUTE_IF_SET_IN_BITMAP (e, 0, i, bi)
5451 equiv_vr = get_vr_for_comparison (i);
5453 t = compare_range_with_value (comp, &equiv_vr, val, &sop);
5456 /* If we get different answers from different members
5457 of the equivalence set this check must be in a dead
5458 code region. Folding it to a trap representation
5459 would be correct here. For now just return don't-know. */
5469 used_strict_overflow = 0;
5470 else if (used_strict_overflow < 0)
5471 used_strict_overflow = 1;
5476 && used_strict_overflow > 0)
5477 *strict_overflow_p = true;
5483 /* Given a comparison code COMP and names N1 and N2, compare all the
5484 ranges equivalent to N1 against all the ranges equivalent to N2
5485 to determine the value of N1 COMP N2. Return the same value
5486 returned by compare_ranges. Set *STRICT_OVERFLOW_P to indicate
5487 whether we relied on an overflow infinity in the comparison. */
5491 compare_names (enum tree_code comp, tree n1, tree n2,
5492 bool *strict_overflow_p)
5496 bitmap_iterator bi1, bi2;
5498 int used_strict_overflow;
5499 static bitmap_obstack *s_obstack = NULL;
5500 static bitmap s_e1 = NULL, s_e2 = NULL;
5502 /* Compare the ranges of every name equivalent to N1 against the
5503 ranges of every name equivalent to N2. */
5504 e1 = get_value_range (n1)->equiv;
5505 e2 = get_value_range (n2)->equiv;
5507 /* Use the fake bitmaps if e1 or e2 are not available. */
5508 if (s_obstack == NULL)
5510 s_obstack = XNEW (bitmap_obstack);
5511 bitmap_obstack_initialize (s_obstack);
5512 s_e1 = BITMAP_ALLOC (s_obstack);
5513 s_e2 = BITMAP_ALLOC (s_obstack);
5520 /* Add N1 and N2 to their own set of equivalences to avoid
5521 duplicating the body of the loop just to check N1 and N2
5523 bitmap_set_bit (e1, SSA_NAME_VERSION (n1));
5524 bitmap_set_bit (e2, SSA_NAME_VERSION (n2));
5526 /* If the equivalence sets have a common intersection, then the two
5527 names can be compared without checking their ranges. */
5528 if (bitmap_intersect_p (e1, e2))
5530 bitmap_clear_bit (e1, SSA_NAME_VERSION (n1));
5531 bitmap_clear_bit (e2, SSA_NAME_VERSION (n2));
5533 return (comp == EQ_EXPR || comp == GE_EXPR || comp == LE_EXPR)
5535 : boolean_false_node;
5538 /* Start at -1. Set it to 0 if we do a comparison without relying
5539 on overflow, or 1 if all comparisons rely on overflow. */
5540 used_strict_overflow = -1;
5542 /* Otherwise, compare all the equivalent ranges. First, add N1 and
5543 N2 to their own set of equivalences to avoid duplicating the body
5544 of the loop just to check N1 and N2 ranges. */
5545 EXECUTE_IF_SET_IN_BITMAP (e1, 0, i1, bi1)
5547 value_range_t vr1 = get_vr_for_comparison (i1);
5549 t = retval = NULL_TREE;
5550 EXECUTE_IF_SET_IN_BITMAP (e2, 0, i2, bi2)
5554 value_range_t vr2 = get_vr_for_comparison (i2);
5556 t = compare_ranges (comp, &vr1, &vr2, &sop);
5559 /* If we get different answers from different members
5560 of the equivalence set this check must be in a dead
5561 code region. Folding it to a trap representation
5562 would be correct here. For now just return don't-know. */
5566 bitmap_clear_bit (e1, SSA_NAME_VERSION (n1));
5567 bitmap_clear_bit (e2, SSA_NAME_VERSION (n2));
5573 used_strict_overflow = 0;
5574 else if (used_strict_overflow < 0)
5575 used_strict_overflow = 1;
5581 bitmap_clear_bit (e1, SSA_NAME_VERSION (n1));
5582 bitmap_clear_bit (e2, SSA_NAME_VERSION (n2));
5583 if (used_strict_overflow > 0)
5584 *strict_overflow_p = true;
5589 /* None of the equivalent ranges are useful in computing this
5591 bitmap_clear_bit (e1, SSA_NAME_VERSION (n1));
5592 bitmap_clear_bit (e2, SSA_NAME_VERSION (n2));
5596 /* Helper function for vrp_evaluate_conditional_warnv. */
5599 vrp_evaluate_conditional_warnv_with_ops_using_ranges (enum tree_code code,
5601 bool * strict_overflow_p)
5603 value_range_t *vr0, *vr1;
5605 vr0 = (TREE_CODE (op0) == SSA_NAME) ? get_value_range (op0) : NULL;
5606 vr1 = (TREE_CODE (op1) == SSA_NAME) ? get_value_range (op1) : NULL;
5609 return compare_ranges (code, vr0, vr1, strict_overflow_p);
5610 else if (vr0 && vr1 == NULL)
5611 return compare_range_with_value (code, vr0, op1, strict_overflow_p);
5612 else if (vr0 == NULL && vr1)
5613 return (compare_range_with_value
5614 (swap_tree_comparison (code), vr1, op0, strict_overflow_p));
5618 /* Helper function for vrp_evaluate_conditional_warnv. */
5621 vrp_evaluate_conditional_warnv_with_ops (enum tree_code code, tree op0,
5622 tree op1, bool use_equiv_p,
5623 bool *strict_overflow_p, bool *only_ranges)
5627 *only_ranges = true;
5629 /* We only deal with integral and pointer types. */
5630 if (!INTEGRAL_TYPE_P (TREE_TYPE (op0))
5631 && !POINTER_TYPE_P (TREE_TYPE (op0)))
5637 && (ret = vrp_evaluate_conditional_warnv_with_ops_using_ranges
5638 (code, op0, op1, strict_overflow_p)))
5640 *only_ranges = false;
5641 if (TREE_CODE (op0) == SSA_NAME && TREE_CODE (op1) == SSA_NAME)
5642 return compare_names (code, op0, op1, strict_overflow_p);
5643 else if (TREE_CODE (op0) == SSA_NAME)
5644 return compare_name_with_value (code, op0, op1, strict_overflow_p);
5645 else if (TREE_CODE (op1) == SSA_NAME)
5646 return (compare_name_with_value
5647 (swap_tree_comparison (code), op1, op0, strict_overflow_p));
5650 return vrp_evaluate_conditional_warnv_with_ops_using_ranges (code, op0, op1,
5655 /* Given (CODE OP0 OP1) within STMT, try to simplify it based on value range
5656 information. Return NULL if the conditional can not be evaluated.
5657 The ranges of all the names equivalent with the operands in COND
5658 will be used when trying to compute the value. If the result is
5659 based on undefined signed overflow, issue a warning if
5663 vrp_evaluate_conditional (enum tree_code code, tree op0, tree op1, gimple stmt)
5669 /* Some passes and foldings leak constants with overflow flag set
5670 into the IL. Avoid doing wrong things with these and bail out. */
5671 if ((TREE_CODE (op0) == INTEGER_CST
5672 && TREE_OVERFLOW (op0))
5673 || (TREE_CODE (op1) == INTEGER_CST
5674 && TREE_OVERFLOW (op1)))
5678 ret = vrp_evaluate_conditional_warnv_with_ops (code, op0, op1, true, &sop,
5683 enum warn_strict_overflow_code wc;
5684 const char* warnmsg;
5686 if (is_gimple_min_invariant (ret))
5688 wc = WARN_STRICT_OVERFLOW_CONDITIONAL;
5689 warnmsg = G_("assuming signed overflow does not occur when "
5690 "simplifying conditional to constant");
5694 wc = WARN_STRICT_OVERFLOW_COMPARISON;
5695 warnmsg = G_("assuming signed overflow does not occur when "
5696 "simplifying conditional");
5699 if (issue_strict_overflow_warning (wc))
5701 location_t location;
5703 if (!gimple_has_location (stmt))
5704 location = input_location;
5706 location = gimple_location (stmt);
5707 warning_at (location, OPT_Wstrict_overflow, "%s", warnmsg);
5711 if (warn_type_limits
5712 && ret && only_ranges
5713 && TREE_CODE_CLASS (code) == tcc_comparison
5714 && TREE_CODE (op0) == SSA_NAME)
5716 /* If the comparison is being folded and the operand on the LHS
5717 is being compared against a constant value that is outside of
5718 the natural range of OP0's type, then the predicate will
5719 always fold regardless of the value of OP0. If -Wtype-limits
5720 was specified, emit a warning. */
5721 tree type = TREE_TYPE (op0);
5722 value_range_t *vr0 = get_value_range (op0);
5724 if (vr0->type != VR_VARYING
5725 && INTEGRAL_TYPE_P (type)
5726 && vrp_val_is_min (vr0->min)
5727 && vrp_val_is_max (vr0->max)
5728 && is_gimple_min_invariant (op1))
5730 location_t location;
5732 if (!gimple_has_location (stmt))
5733 location = input_location;
5735 location = gimple_location (stmt);
5737 warning_at (location, OPT_Wtype_limits,
5739 ? G_("comparison always false "
5740 "due to limited range of data type")
5741 : G_("comparison always true "
5742 "due to limited range of data type"));
5750 /* Visit conditional statement STMT. If we can determine which edge
5751 will be taken out of STMT's basic block, record it in
5752 *TAKEN_EDGE_P and return SSA_PROP_INTERESTING. Otherwise, return
5753 SSA_PROP_VARYING. */
5755 static enum ssa_prop_result
5756 vrp_visit_cond_stmt (gimple stmt, edge *taken_edge_p)
5761 *taken_edge_p = NULL;
5763 if (dump_file && (dump_flags & TDF_DETAILS))
5768 fprintf (dump_file, "\nVisiting conditional with predicate: ");
5769 print_gimple_stmt (dump_file, stmt, 0, 0);
5770 fprintf (dump_file, "\nWith known ranges\n");
5772 FOR_EACH_SSA_TREE_OPERAND (use, stmt, i, SSA_OP_USE)
5774 fprintf (dump_file, "\t");
5775 print_generic_expr (dump_file, use, 0);
5776 fprintf (dump_file, ": ");
5777 dump_value_range (dump_file, vr_value[SSA_NAME_VERSION (use)]);
5780 fprintf (dump_file, "\n");
5783 /* Compute the value of the predicate COND by checking the known
5784 ranges of each of its operands.
5786 Note that we cannot evaluate all the equivalent ranges here
5787 because those ranges may not yet be final and with the current
5788 propagation strategy, we cannot determine when the value ranges
5789 of the names in the equivalence set have changed.
5791 For instance, given the following code fragment
5795 i_14 = ASSERT_EXPR <i_5, i_5 != 0>
5799 Assume that on the first visit to i_14, i_5 has the temporary
5800 range [8, 8] because the second argument to the PHI function is
5801 not yet executable. We derive the range ~[0, 0] for i_14 and the
5802 equivalence set { i_5 }. So, when we visit 'if (i_14 == 1)' for
5803 the first time, since i_14 is equivalent to the range [8, 8], we
5804 determine that the predicate is always false.
5806 On the next round of propagation, i_13 is determined to be
5807 VARYING, which causes i_5 to drop down to VARYING. So, another
5808 visit to i_14 is scheduled. In this second visit, we compute the
5809 exact same range and equivalence set for i_14, namely ~[0, 0] and
5810 { i_5 }. But we did not have the previous range for i_5
5811 registered, so vrp_visit_assignment thinks that the range for
5812 i_14 has not changed. Therefore, the predicate 'if (i_14 == 1)'
5813 is not visited again, which stops propagation from visiting
5814 statements in the THEN clause of that if().
5816 To properly fix this we would need to keep the previous range
5817 value for the names in the equivalence set. This way we would've
5818 discovered that from one visit to the other i_5 changed from
5819 range [8, 8] to VR_VARYING.
5821 However, fixing this apparent limitation may not be worth the
5822 additional checking. Testing on several code bases (GCC, DLV,
5823 MICO, TRAMP3D and SPEC2000) showed that doing this results in
5824 4 more predicates folded in SPEC. */
5827 val = vrp_evaluate_conditional_warnv_with_ops (gimple_cond_code (stmt),
5828 gimple_cond_lhs (stmt),
5829 gimple_cond_rhs (stmt),
5834 *taken_edge_p = find_taken_edge (gimple_bb (stmt), val);
5837 if (dump_file && (dump_flags & TDF_DETAILS))
5839 "\nIgnoring predicate evaluation because "
5840 "it assumes that signed overflow is undefined");
5845 if (dump_file && (dump_flags & TDF_DETAILS))
5847 fprintf (dump_file, "\nPredicate evaluates to: ");
5848 if (val == NULL_TREE)
5849 fprintf (dump_file, "DON'T KNOW\n");
5851 print_generic_stmt (dump_file, val, 0);
5854 return (*taken_edge_p) ? SSA_PROP_INTERESTING : SSA_PROP_VARYING;
5857 /* Searches the case label vector VEC for the index *IDX of the CASE_LABEL
5858 that includes the value VAL. The search is restricted to the range
5859 [START_IDX, n - 1] where n is the size of VEC.
5861 If there is a CASE_LABEL for VAL, its index is placed in IDX and true is
5864 If there is no CASE_LABEL for VAL and there is one that is larger than VAL,
5865 it is placed in IDX and false is returned.
5867 If VAL is larger than any CASE_LABEL, n is placed on IDX and false is
5871 find_case_label_index (gimple stmt, size_t start_idx, tree val, size_t *idx)
5873 size_t n = gimple_switch_num_labels (stmt);
5876 /* Find case label for minimum of the value range or the next one.
5877 At each iteration we are searching in [low, high - 1]. */
5879 for (low = start_idx, high = n; high != low; )
5883 /* Note that i != high, so we never ask for n. */
5884 size_t i = (high + low) / 2;
5885 t = gimple_switch_label (stmt, i);
5887 /* Cache the result of comparing CASE_LOW and val. */
5888 cmp = tree_int_cst_compare (CASE_LOW (t), val);
5892 /* Ranges cannot be empty. */
5901 if (CASE_HIGH (t) != NULL
5902 && tree_int_cst_compare (CASE_HIGH (t), val) >= 0)
5914 /* Searches the case label vector VEC for the range of CASE_LABELs that is used
5915 for values between MIN and MAX. The first index is placed in MIN_IDX. The
5916 last index is placed in MAX_IDX. If the range of CASE_LABELs is empty
5917 then MAX_IDX < MIN_IDX.
5918 Returns true if the default label is not needed. */
5921 find_case_label_range (gimple stmt, tree min, tree max, size_t *min_idx,
5925 bool min_take_default = !find_case_label_index (stmt, 1, min, &i);
5926 bool max_take_default = !find_case_label_index (stmt, i, max, &j);
5930 && max_take_default)
5932 /* Only the default case label reached.
5933 Return an empty range. */
5940 bool take_default = min_take_default || max_take_default;
5944 if (max_take_default)
5947 /* If the case label range is continuous, we do not need
5948 the default case label. Verify that. */
5949 high = CASE_LOW (gimple_switch_label (stmt, i));
5950 if (CASE_HIGH (gimple_switch_label (stmt, i)))
5951 high = CASE_HIGH (gimple_switch_label (stmt, i));
5952 for (k = i + 1; k <= j; ++k)
5954 low = CASE_LOW (gimple_switch_label (stmt, k));
5955 if (!integer_onep (int_const_binop (MINUS_EXPR, low, high, 0)))
5957 take_default = true;
5961 if (CASE_HIGH (gimple_switch_label (stmt, k)))
5962 high = CASE_HIGH (gimple_switch_label (stmt, k));
5967 return !take_default;
5971 /* Visit switch statement STMT. If we can determine which edge
5972 will be taken out of STMT's basic block, record it in
5973 *TAKEN_EDGE_P and return SSA_PROP_INTERESTING. Otherwise, return
5974 SSA_PROP_VARYING. */
5976 static enum ssa_prop_result
5977 vrp_visit_switch_stmt (gimple stmt, edge *taken_edge_p)
5981 size_t i = 0, j = 0;
5984 *taken_edge_p = NULL;
5985 op = gimple_switch_index (stmt);
5986 if (TREE_CODE (op) != SSA_NAME)
5987 return SSA_PROP_VARYING;
5989 vr = get_value_range (op);
5990 if (dump_file && (dump_flags & TDF_DETAILS))
5992 fprintf (dump_file, "\nVisiting switch expression with operand ");
5993 print_generic_expr (dump_file, op, 0);
5994 fprintf (dump_file, " with known range ");
5995 dump_value_range (dump_file, vr);
5996 fprintf (dump_file, "\n");
5999 if (vr->type != VR_RANGE
6000 || symbolic_range_p (vr))
6001 return SSA_PROP_VARYING;
6003 /* Find the single edge that is taken from the switch expression. */
6004 take_default = !find_case_label_range (stmt, vr->min, vr->max, &i, &j);
6006 /* Check if the range spans no CASE_LABEL. If so, we only reach the default
6010 gcc_assert (take_default);
6011 val = gimple_switch_default_label (stmt);
6015 /* Check if labels with index i to j and maybe the default label
6016 are all reaching the same label. */
6018 val = gimple_switch_label (stmt, i);
6020 && CASE_LABEL (gimple_switch_default_label (stmt))
6021 != CASE_LABEL (val))
6023 if (dump_file && (dump_flags & TDF_DETAILS))
6024 fprintf (dump_file, " not a single destination for this "
6026 return SSA_PROP_VARYING;
6028 for (++i; i <= j; ++i)
6030 if (CASE_LABEL (gimple_switch_label (stmt, i)) != CASE_LABEL (val))
6032 if (dump_file && (dump_flags & TDF_DETAILS))
6033 fprintf (dump_file, " not a single destination for this "
6035 return SSA_PROP_VARYING;
6040 *taken_edge_p = find_edge (gimple_bb (stmt),
6041 label_to_block (CASE_LABEL (val)));
6043 if (dump_file && (dump_flags & TDF_DETAILS))
6045 fprintf (dump_file, " will take edge to ");
6046 print_generic_stmt (dump_file, CASE_LABEL (val), 0);
6049 return SSA_PROP_INTERESTING;
6053 /* Evaluate statement STMT. If the statement produces a useful range,
6054 return SSA_PROP_INTERESTING and record the SSA name with the
6055 interesting range into *OUTPUT_P.
6057 If STMT is a conditional branch and we can determine its truth
6058 value, the taken edge is recorded in *TAKEN_EDGE_P.
6060 If STMT produces a varying value, return SSA_PROP_VARYING. */
6062 static enum ssa_prop_result
6063 vrp_visit_stmt (gimple stmt, edge *taken_edge_p, tree *output_p)
6068 if (dump_file && (dump_flags & TDF_DETAILS))
6070 fprintf (dump_file, "\nVisiting statement:\n");
6071 print_gimple_stmt (dump_file, stmt, 0, dump_flags);
6072 fprintf (dump_file, "\n");
6075 if (!stmt_interesting_for_vrp (stmt))
6076 gcc_assert (stmt_ends_bb_p (stmt));
6077 else if (is_gimple_assign (stmt) || is_gimple_call (stmt))
6079 /* In general, assignments with virtual operands are not useful
6080 for deriving ranges, with the obvious exception of calls to
6081 builtin functions. */
6083 if ((is_gimple_call (stmt)
6084 && gimple_call_fndecl (stmt) != NULL_TREE
6085 && DECL_IS_BUILTIN (gimple_call_fndecl (stmt)))
6086 || !gimple_vuse (stmt))
6087 return vrp_visit_assignment_or_call (stmt, output_p);
6089 else if (gimple_code (stmt) == GIMPLE_COND)
6090 return vrp_visit_cond_stmt (stmt, taken_edge_p);
6091 else if (gimple_code (stmt) == GIMPLE_SWITCH)
6092 return vrp_visit_switch_stmt (stmt, taken_edge_p);
6094 /* All other statements produce nothing of interest for VRP, so mark
6095 their outputs varying and prevent further simulation. */
6096 FOR_EACH_SSA_TREE_OPERAND (def, stmt, iter, SSA_OP_DEF)
6097 set_value_range_to_varying (get_value_range (def));
6099 return SSA_PROP_VARYING;
6103 /* Meet operation for value ranges. Given two value ranges VR0 and
6104 VR1, store in VR0 a range that contains both VR0 and VR1. This
6105 may not be the smallest possible such range. */
6108 vrp_meet (value_range_t *vr0, value_range_t *vr1)
6110 if (vr0->type == VR_UNDEFINED)
6112 copy_value_range (vr0, vr1);
6116 if (vr1->type == VR_UNDEFINED)
6118 /* Nothing to do. VR0 already has the resulting range. */
6122 if (vr0->type == VR_VARYING)
6124 /* Nothing to do. VR0 already has the resulting range. */
6128 if (vr1->type == VR_VARYING)
6130 set_value_range_to_varying (vr0);
6134 if (vr0->type == VR_RANGE && vr1->type == VR_RANGE)
6139 /* Compute the convex hull of the ranges. The lower limit of
6140 the new range is the minimum of the two ranges. If they
6141 cannot be compared, then give up. */
6142 cmp = compare_values (vr0->min, vr1->min);
6143 if (cmp == 0 || cmp == 1)
6150 /* Similarly, the upper limit of the new range is the maximum
6151 of the two ranges. If they cannot be compared, then
6153 cmp = compare_values (vr0->max, vr1->max);
6154 if (cmp == 0 || cmp == -1)
6161 /* Check for useless ranges. */
6162 if (INTEGRAL_TYPE_P (TREE_TYPE (min))
6163 && ((vrp_val_is_min (min) || is_overflow_infinity (min))
6164 && (vrp_val_is_max (max) || is_overflow_infinity (max))))
6167 /* The resulting set of equivalences is the intersection of
6169 if (vr0->equiv && vr1->equiv && vr0->equiv != vr1->equiv)
6170 bitmap_and_into (vr0->equiv, vr1->equiv);
6171 else if (vr0->equiv && !vr1->equiv)
6172 bitmap_clear (vr0->equiv);
6174 set_value_range (vr0, vr0->type, min, max, vr0->equiv);
6176 else if (vr0->type == VR_ANTI_RANGE && vr1->type == VR_ANTI_RANGE)
6178 /* Two anti-ranges meet only if their complements intersect.
6179 Only handle the case of identical ranges. */
6180 if (compare_values (vr0->min, vr1->min) == 0
6181 && compare_values (vr0->max, vr1->max) == 0
6182 && compare_values (vr0->min, vr0->max) == 0)
6184 /* The resulting set of equivalences is the intersection of
6186 if (vr0->equiv && vr1->equiv && vr0->equiv != vr1->equiv)
6187 bitmap_and_into (vr0->equiv, vr1->equiv);
6188 else if (vr0->equiv && !vr1->equiv)
6189 bitmap_clear (vr0->equiv);
6194 else if (vr0->type == VR_ANTI_RANGE || vr1->type == VR_ANTI_RANGE)
6196 /* For a numeric range [VAL1, VAL2] and an anti-range ~[VAL3, VAL4],
6197 only handle the case where the ranges have an empty intersection.
6198 The result of the meet operation is the anti-range. */
6199 if (!symbolic_range_p (vr0)
6200 && !symbolic_range_p (vr1)
6201 && !value_ranges_intersect_p (vr0, vr1))
6203 /* Copy most of VR1 into VR0. Don't copy VR1's equivalence
6204 set. We need to compute the intersection of the two
6205 equivalence sets. */
6206 if (vr1->type == VR_ANTI_RANGE)
6207 set_value_range (vr0, vr1->type, vr1->min, vr1->max, vr0->equiv);
6209 /* The resulting set of equivalences is the intersection of
6211 if (vr0->equiv && vr1->equiv && vr0->equiv != vr1->equiv)
6212 bitmap_and_into (vr0->equiv, vr1->equiv);
6213 else if (vr0->equiv && !vr1->equiv)
6214 bitmap_clear (vr0->equiv);
6225 /* Failed to find an efficient meet. Before giving up and setting
6226 the result to VARYING, see if we can at least derive a useful
6227 anti-range. FIXME, all this nonsense about distinguishing
6228 anti-ranges from ranges is necessary because of the odd
6229 semantics of range_includes_zero_p and friends. */
6230 if (!symbolic_range_p (vr0)
6231 && ((vr0->type == VR_RANGE && !range_includes_zero_p (vr0))
6232 || (vr0->type == VR_ANTI_RANGE && range_includes_zero_p (vr0)))
6233 && !symbolic_range_p (vr1)
6234 && ((vr1->type == VR_RANGE && !range_includes_zero_p (vr1))
6235 || (vr1->type == VR_ANTI_RANGE && range_includes_zero_p (vr1))))
6237 set_value_range_to_nonnull (vr0, TREE_TYPE (vr0->min));
6239 /* Since this meet operation did not result from the meeting of
6240 two equivalent names, VR0 cannot have any equivalences. */
6242 bitmap_clear (vr0->equiv);
6245 set_value_range_to_varying (vr0);
6249 /* Visit all arguments for PHI node PHI that flow through executable
6250 edges. If a valid value range can be derived from all the incoming
6251 value ranges, set a new range for the LHS of PHI. */
6253 static enum ssa_prop_result
6254 vrp_visit_phi_node (gimple phi)
6257 tree lhs = PHI_RESULT (phi);
6258 value_range_t *lhs_vr = get_value_range (lhs);
6259 value_range_t vr_result = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
6260 int edges, old_edges;
6263 copy_value_range (&vr_result, lhs_vr);
6265 if (dump_file && (dump_flags & TDF_DETAILS))
6267 fprintf (dump_file, "\nVisiting PHI node: ");
6268 print_gimple_stmt (dump_file, phi, 0, dump_flags);
6272 for (i = 0; i < gimple_phi_num_args (phi); i++)
6274 edge e = gimple_phi_arg_edge (phi, i);
6276 if (dump_file && (dump_flags & TDF_DETAILS))
6279 "\n Argument #%d (%d -> %d %sexecutable)\n",
6280 (int) i, e->src->index, e->dest->index,
6281 (e->flags & EDGE_EXECUTABLE) ? "" : "not ");
6284 if (e->flags & EDGE_EXECUTABLE)
6286 tree arg = PHI_ARG_DEF (phi, i);
6287 value_range_t vr_arg;
6291 if (TREE_CODE (arg) == SSA_NAME)
6293 vr_arg = *(get_value_range (arg));
6297 if (is_overflow_infinity (arg))
6299 arg = copy_node (arg);
6300 TREE_OVERFLOW (arg) = 0;
6303 vr_arg.type = VR_RANGE;
6306 vr_arg.equiv = NULL;
6309 if (dump_file && (dump_flags & TDF_DETAILS))
6311 fprintf (dump_file, "\t");
6312 print_generic_expr (dump_file, arg, dump_flags);
6313 fprintf (dump_file, "\n\tValue: ");
6314 dump_value_range (dump_file, &vr_arg);
6315 fprintf (dump_file, "\n");
6318 vrp_meet (&vr_result, &vr_arg);
6320 if (vr_result.type == VR_VARYING)
6325 /* If this is a loop PHI node SCEV may known more about its
6328 && (l = loop_containing_stmt (phi))
6329 && l->header == gimple_bb (phi))
6330 adjust_range_with_scev (&vr_result, l, phi, lhs);
6332 if (vr_result.type == VR_VARYING)
6335 old_edges = vr_phi_edge_counts[SSA_NAME_VERSION (lhs)];
6336 vr_phi_edge_counts[SSA_NAME_VERSION (lhs)] = edges;
6338 /* To prevent infinite iterations in the algorithm, derive ranges
6339 when the new value is slightly bigger or smaller than the
6340 previous one. We don't do this if we have seen a new executable
6341 edge; this helps us avoid an overflow infinity for conditionals
6342 which are not in a loop. */
6343 if (lhs_vr->type == VR_RANGE && vr_result.type == VR_RANGE
6344 && edges <= old_edges)
6346 if (!POINTER_TYPE_P (TREE_TYPE (lhs)))
6348 int cmp_min = compare_values (lhs_vr->min, vr_result.min);
6349 int cmp_max = compare_values (lhs_vr->max, vr_result.max);
6351 /* If the new minimum is smaller or larger than the previous
6352 one, go all the way to -INF. In the first case, to avoid
6353 iterating millions of times to reach -INF, and in the
6354 other case to avoid infinite bouncing between different
6356 if (cmp_min > 0 || cmp_min < 0)
6358 /* If we will end up with a (-INF, +INF) range, set it to
6359 VARYING. Same if the previous max value was invalid for
6360 the type and we'd end up with vr_result.min > vr_result.max. */
6361 if (vrp_val_is_max (vr_result.max)
6362 || compare_values (TYPE_MIN_VALUE (TREE_TYPE (vr_result.min)),
6366 if (!needs_overflow_infinity (TREE_TYPE (vr_result.min))
6367 || !vrp_var_may_overflow (lhs, phi))
6368 vr_result.min = TYPE_MIN_VALUE (TREE_TYPE (vr_result.min));
6369 else if (supports_overflow_infinity (TREE_TYPE (vr_result.min)))
6371 negative_overflow_infinity (TREE_TYPE (vr_result.min));
6376 /* Similarly, if the new maximum is smaller or larger than
6377 the previous one, go all the way to +INF. */
6378 if (cmp_max < 0 || cmp_max > 0)
6380 /* If we will end up with a (-INF, +INF) range, set it to
6381 VARYING. Same if the previous min value was invalid for
6382 the type and we'd end up with vr_result.max < vr_result.min. */
6383 if (vrp_val_is_min (vr_result.min)
6384 || compare_values (TYPE_MAX_VALUE (TREE_TYPE (vr_result.max)),
6388 if (!needs_overflow_infinity (TREE_TYPE (vr_result.max))
6389 || !vrp_var_may_overflow (lhs, phi))
6390 vr_result.max = TYPE_MAX_VALUE (TREE_TYPE (vr_result.max));
6391 else if (supports_overflow_infinity (TREE_TYPE (vr_result.max)))
6393 positive_overflow_infinity (TREE_TYPE (vr_result.max));
6400 /* If the new range is different than the previous value, keep
6402 if (update_value_range (lhs, &vr_result))
6403 return SSA_PROP_INTERESTING;
6405 /* Nothing changed, don't add outgoing edges. */
6406 return SSA_PROP_NOT_INTERESTING;
6408 /* No match found. Set the LHS to VARYING. */
6410 set_value_range_to_varying (lhs_vr);
6411 return SSA_PROP_VARYING;
6414 /* Simplify boolean operations if the source is known
6415 to be already a boolean. */
6417 simplify_truth_ops_using_ranges (gimple_stmt_iterator *gsi, gimple stmt)
6419 enum tree_code rhs_code = gimple_assign_rhs_code (stmt);
6424 bool need_conversion;
6426 op0 = gimple_assign_rhs1 (stmt);
6427 if (TYPE_PRECISION (TREE_TYPE (op0)) != 1)
6429 if (TREE_CODE (op0) != SSA_NAME)
6431 vr = get_value_range (op0);
6433 val = compare_range_with_value (GE_EXPR, vr, integer_zero_node, &sop);
6434 if (!val || !integer_onep (val))
6437 val = compare_range_with_value (LE_EXPR, vr, integer_one_node, &sop);
6438 if (!val || !integer_onep (val))
6442 if (rhs_code == TRUTH_NOT_EXPR)
6445 op1 = build_int_cst (TREE_TYPE (op0), 1);
6449 op1 = gimple_assign_rhs2 (stmt);
6451 /* Reduce number of cases to handle. */
6452 if (is_gimple_min_invariant (op1))
6454 /* Exclude anything that should have been already folded. */
6455 if (rhs_code != EQ_EXPR
6456 && rhs_code != NE_EXPR
6457 && rhs_code != TRUTH_XOR_EXPR)
6460 if (!integer_zerop (op1)
6461 && !integer_onep (op1)
6462 && !integer_all_onesp (op1))
6465 /* Limit the number of cases we have to consider. */
6466 if (rhs_code == EQ_EXPR)
6469 op1 = fold_unary (TRUTH_NOT_EXPR, TREE_TYPE (op1), op1);
6474 /* Punt on A == B as there is no BIT_XNOR_EXPR. */
6475 if (rhs_code == EQ_EXPR)
6478 if (TYPE_PRECISION (TREE_TYPE (op1)) != 1)
6480 vr = get_value_range (op1);
6481 val = compare_range_with_value (GE_EXPR, vr, integer_zero_node, &sop);
6482 if (!val || !integer_onep (val))
6485 val = compare_range_with_value (LE_EXPR, vr, integer_one_node, &sop);
6486 if (!val || !integer_onep (val))
6492 if (sop && issue_strict_overflow_warning (WARN_STRICT_OVERFLOW_MISC))
6494 location_t location;
6496 if (!gimple_has_location (stmt))
6497 location = input_location;
6499 location = gimple_location (stmt);
6501 if (rhs_code == TRUTH_AND_EXPR || rhs_code == TRUTH_OR_EXPR)
6502 warning_at (location, OPT_Wstrict_overflow,
6503 _("assuming signed overflow does not occur when "
6504 "simplifying && or || to & or |"));
6506 warning_at (location, OPT_Wstrict_overflow,
6507 _("assuming signed overflow does not occur when "
6508 "simplifying ==, != or ! to identity or ^"));
6512 !useless_type_conversion_p (TREE_TYPE (gimple_assign_lhs (stmt)),
6515 /* Make sure to not sign-extend -1 as a boolean value. */
6517 && !TYPE_UNSIGNED (TREE_TYPE (op0))
6518 && TYPE_PRECISION (TREE_TYPE (op0)) == 1)
6523 case TRUTH_AND_EXPR:
6524 rhs_code = BIT_AND_EXPR;
6527 rhs_code = BIT_IOR_EXPR;
6529 case TRUTH_XOR_EXPR:
6531 if (integer_zerop (op1))
6533 gimple_assign_set_rhs_with_ops (gsi,
6534 need_conversion ? NOP_EXPR : SSA_NAME,
6536 update_stmt (gsi_stmt (*gsi));
6540 rhs_code = BIT_XOR_EXPR;
6546 if (need_conversion)
6549 gimple_assign_set_rhs_with_ops (gsi, rhs_code, op0, op1);
6550 update_stmt (gsi_stmt (*gsi));
6554 /* Simplify a division or modulo operator to a right shift or
6555 bitwise and if the first operand is unsigned or is greater
6556 than zero and the second operand is an exact power of two. */
6559 simplify_div_or_mod_using_ranges (gimple stmt)
6561 enum tree_code rhs_code = gimple_assign_rhs_code (stmt);
6563 tree op0 = gimple_assign_rhs1 (stmt);
6564 tree op1 = gimple_assign_rhs2 (stmt);
6565 value_range_t *vr = get_value_range (gimple_assign_rhs1 (stmt));
6567 if (TYPE_UNSIGNED (TREE_TYPE (op0)))
6569 val = integer_one_node;
6575 val = compare_range_with_value (GE_EXPR, vr, integer_zero_node, &sop);
6579 && integer_onep (val)
6580 && issue_strict_overflow_warning (WARN_STRICT_OVERFLOW_MISC))
6582 location_t location;
6584 if (!gimple_has_location (stmt))
6585 location = input_location;
6587 location = gimple_location (stmt);
6588 warning_at (location, OPT_Wstrict_overflow,
6589 "assuming signed overflow does not occur when "
6590 "simplifying %</%> or %<%%%> to %<>>%> or %<&%>");
6594 if (val && integer_onep (val))
6598 if (rhs_code == TRUNC_DIV_EXPR)
6600 t = build_int_cst (NULL_TREE, tree_log2 (op1));
6601 gimple_assign_set_rhs_code (stmt, RSHIFT_EXPR);
6602 gimple_assign_set_rhs1 (stmt, op0);
6603 gimple_assign_set_rhs2 (stmt, t);
6607 t = build_int_cst (TREE_TYPE (op1), 1);
6608 t = int_const_binop (MINUS_EXPR, op1, t, 0);
6609 t = fold_convert (TREE_TYPE (op0), t);
6611 gimple_assign_set_rhs_code (stmt, BIT_AND_EXPR);
6612 gimple_assign_set_rhs1 (stmt, op0);
6613 gimple_assign_set_rhs2 (stmt, t);
6623 /* If the operand to an ABS_EXPR is >= 0, then eliminate the
6624 ABS_EXPR. If the operand is <= 0, then simplify the
6625 ABS_EXPR into a NEGATE_EXPR. */
6628 simplify_abs_using_ranges (gimple stmt)
6631 tree op = gimple_assign_rhs1 (stmt);
6632 tree type = TREE_TYPE (op);
6633 value_range_t *vr = get_value_range (op);
6635 if (TYPE_UNSIGNED (type))
6637 val = integer_zero_node;
6643 val = compare_range_with_value (LE_EXPR, vr, integer_zero_node, &sop);
6647 val = compare_range_with_value (GE_EXPR, vr, integer_zero_node,
6652 if (integer_zerop (val))
6653 val = integer_one_node;
6654 else if (integer_onep (val))
6655 val = integer_zero_node;
6660 && (integer_onep (val) || integer_zerop (val)))
6662 if (sop && issue_strict_overflow_warning (WARN_STRICT_OVERFLOW_MISC))
6664 location_t location;
6666 if (!gimple_has_location (stmt))
6667 location = input_location;
6669 location = gimple_location (stmt);
6670 warning_at (location, OPT_Wstrict_overflow,
6671 "assuming signed overflow does not occur when "
6672 "simplifying %<abs (X)%> to %<X%> or %<-X%>");
6675 gimple_assign_set_rhs1 (stmt, op);
6676 if (integer_onep (val))
6677 gimple_assign_set_rhs_code (stmt, NEGATE_EXPR);
6679 gimple_assign_set_rhs_code (stmt, SSA_NAME);
6688 /* We are comparing trees OP0 and OP1 using COND_CODE. OP0 has
6689 a known value range VR.
6691 If there is one and only one value which will satisfy the
6692 conditional, then return that value. Else return NULL. */
6695 test_for_singularity (enum tree_code cond_code, tree op0,
6696 tree op1, value_range_t *vr)
6701 /* Extract minimum/maximum values which satisfy the
6702 the conditional as it was written. */
6703 if (cond_code == LE_EXPR || cond_code == LT_EXPR)
6705 /* This should not be negative infinity; there is no overflow
6707 min = TYPE_MIN_VALUE (TREE_TYPE (op0));
6710 if (cond_code == LT_EXPR && !is_overflow_infinity (max))
6712 tree one = build_int_cst (TREE_TYPE (op0), 1);
6713 max = fold_build2 (MINUS_EXPR, TREE_TYPE (op0), max, one);
6715 TREE_NO_WARNING (max) = 1;
6718 else if (cond_code == GE_EXPR || cond_code == GT_EXPR)
6720 /* This should not be positive infinity; there is no overflow
6722 max = TYPE_MAX_VALUE (TREE_TYPE (op0));
6725 if (cond_code == GT_EXPR && !is_overflow_infinity (min))
6727 tree one = build_int_cst (TREE_TYPE (op0), 1);
6728 min = fold_build2 (PLUS_EXPR, TREE_TYPE (op0), min, one);
6730 TREE_NO_WARNING (min) = 1;
6734 /* Now refine the minimum and maximum values using any
6735 value range information we have for op0. */
6738 if (compare_values (vr->min, min) == 1)
6740 if (compare_values (vr->max, max) == -1)
6743 /* If the new min/max values have converged to a single value,
6744 then there is only one value which can satisfy the condition,
6745 return that value. */
6746 if (operand_equal_p (min, max, 0) && is_gimple_min_invariant (min))
6752 /* Simplify a conditional using a relational operator to an equality
6753 test if the range information indicates only one value can satisfy
6754 the original conditional. */
6757 simplify_cond_using_ranges (gimple stmt)
6759 tree op0 = gimple_cond_lhs (stmt);
6760 tree op1 = gimple_cond_rhs (stmt);
6761 enum tree_code cond_code = gimple_cond_code (stmt);
6763 if (cond_code != NE_EXPR
6764 && cond_code != EQ_EXPR
6765 && TREE_CODE (op0) == SSA_NAME
6766 && INTEGRAL_TYPE_P (TREE_TYPE (op0))
6767 && is_gimple_min_invariant (op1))
6769 value_range_t *vr = get_value_range (op0);
6771 /* If we have range information for OP0, then we might be
6772 able to simplify this conditional. */
6773 if (vr->type == VR_RANGE)
6775 tree new_tree = test_for_singularity (cond_code, op0, op1, vr);
6781 fprintf (dump_file, "Simplified relational ");
6782 print_gimple_stmt (dump_file, stmt, 0, 0);
6783 fprintf (dump_file, " into ");
6786 gimple_cond_set_code (stmt, EQ_EXPR);
6787 gimple_cond_set_lhs (stmt, op0);
6788 gimple_cond_set_rhs (stmt, new_tree);
6794 print_gimple_stmt (dump_file, stmt, 0, 0);
6795 fprintf (dump_file, "\n");
6801 /* Try again after inverting the condition. We only deal
6802 with integral types here, so no need to worry about
6803 issues with inverting FP comparisons. */
6804 cond_code = invert_tree_comparison (cond_code, false);
6805 new_tree = test_for_singularity (cond_code, op0, op1, vr);
6811 fprintf (dump_file, "Simplified relational ");
6812 print_gimple_stmt (dump_file, stmt, 0, 0);
6813 fprintf (dump_file, " into ");
6816 gimple_cond_set_code (stmt, NE_EXPR);
6817 gimple_cond_set_lhs (stmt, op0);
6818 gimple_cond_set_rhs (stmt, new_tree);
6824 print_gimple_stmt (dump_file, stmt, 0, 0);
6825 fprintf (dump_file, "\n");
6836 /* Simplify a switch statement using the value range of the switch
6840 simplify_switch_using_ranges (gimple stmt)
6842 tree op = gimple_switch_index (stmt);
6847 size_t i = 0, j = 0, n, n2;
6851 if (TREE_CODE (op) == SSA_NAME)
6853 vr = get_value_range (op);
6855 /* We can only handle integer ranges. */
6856 if (vr->type != VR_RANGE
6857 || symbolic_range_p (vr))
6860 /* Find case label for min/max of the value range. */
6861 take_default = !find_case_label_range (stmt, vr->min, vr->max, &i, &j);
6863 else if (TREE_CODE (op) == INTEGER_CST)
6865 take_default = !find_case_label_index (stmt, 1, op, &i);
6879 n = gimple_switch_num_labels (stmt);
6881 /* Bail out if this is just all edges taken. */
6887 /* Build a new vector of taken case labels. */
6888 vec2 = make_tree_vec (j - i + 1 + (int)take_default);
6891 /* Add the default edge, if necessary. */
6893 TREE_VEC_ELT (vec2, n2++) = gimple_switch_default_label (stmt);
6895 for (; i <= j; ++i, ++n2)
6896 TREE_VEC_ELT (vec2, n2) = gimple_switch_label (stmt, i);
6898 /* Mark needed edges. */
6899 for (i = 0; i < n2; ++i)
6901 e = find_edge (gimple_bb (stmt),
6902 label_to_block (CASE_LABEL (TREE_VEC_ELT (vec2, i))));
6903 e->aux = (void *)-1;
6906 /* Queue not needed edges for later removal. */
6907 FOR_EACH_EDGE (e, ei, gimple_bb (stmt)->succs)
6909 if (e->aux == (void *)-1)
6915 if (dump_file && (dump_flags & TDF_DETAILS))
6917 fprintf (dump_file, "removing unreachable case label\n");
6919 VEC_safe_push (edge, heap, to_remove_edges, e);
6920 e->flags &= ~EDGE_EXECUTABLE;
6923 /* And queue an update for the stmt. */
6926 VEC_safe_push (switch_update, heap, to_update_switch_stmts, &su);
6930 /* Simplify STMT using ranges if possible. */
6933 simplify_stmt_using_ranges (gimple_stmt_iterator *gsi)
6935 gimple stmt = gsi_stmt (*gsi);
6936 if (is_gimple_assign (stmt))
6938 enum tree_code rhs_code = gimple_assign_rhs_code (stmt);
6944 case TRUTH_NOT_EXPR:
6945 case TRUTH_AND_EXPR:
6947 case TRUTH_XOR_EXPR:
6948 /* Transform EQ_EXPR, NE_EXPR, TRUTH_NOT_EXPR into BIT_XOR_EXPR
6949 or identity if the RHS is zero or one, and the LHS are known
6950 to be boolean values. Transform all TRUTH_*_EXPR into
6951 BIT_*_EXPR if both arguments are known to be boolean values. */
6952 if (INTEGRAL_TYPE_P (TREE_TYPE (gimple_assign_rhs1 (stmt))))
6953 return simplify_truth_ops_using_ranges (gsi, stmt);
6956 /* Transform TRUNC_DIV_EXPR and TRUNC_MOD_EXPR into RSHIFT_EXPR
6957 and BIT_AND_EXPR respectively if the first operand is greater
6958 than zero and the second operand is an exact power of two. */
6959 case TRUNC_DIV_EXPR:
6960 case TRUNC_MOD_EXPR:
6961 if (INTEGRAL_TYPE_P (TREE_TYPE (gimple_assign_rhs1 (stmt)))
6962 && integer_pow2p (gimple_assign_rhs2 (stmt)))
6963 return simplify_div_or_mod_using_ranges (stmt);
6966 /* Transform ABS (X) into X or -X as appropriate. */
6968 if (TREE_CODE (gimple_assign_rhs1 (stmt)) == SSA_NAME
6969 && INTEGRAL_TYPE_P (TREE_TYPE (gimple_assign_rhs1 (stmt))))
6970 return simplify_abs_using_ranges (stmt);
6977 else if (gimple_code (stmt) == GIMPLE_COND)
6978 return simplify_cond_using_ranges (stmt);
6979 else if (gimple_code (stmt) == GIMPLE_SWITCH)
6980 return simplify_switch_using_ranges (stmt);
6985 /* If the statement pointed by SI has a predicate whose value can be
6986 computed using the value range information computed by VRP, compute
6987 its value and return true. Otherwise, return false. */
6990 fold_predicate_in (gimple_stmt_iterator *si)
6992 bool assignment_p = false;
6994 gimple stmt = gsi_stmt (*si);
6996 if (is_gimple_assign (stmt)
6997 && TREE_CODE_CLASS (gimple_assign_rhs_code (stmt)) == tcc_comparison)
6999 assignment_p = true;
7000 val = vrp_evaluate_conditional (gimple_assign_rhs_code (stmt),
7001 gimple_assign_rhs1 (stmt),
7002 gimple_assign_rhs2 (stmt),
7005 else if (gimple_code (stmt) == GIMPLE_COND)
7006 val = vrp_evaluate_conditional (gimple_cond_code (stmt),
7007 gimple_cond_lhs (stmt),
7008 gimple_cond_rhs (stmt),
7016 val = fold_convert (gimple_expr_type (stmt), val);
7020 fprintf (dump_file, "Folding predicate ");
7021 print_gimple_expr (dump_file, stmt, 0, 0);
7022 fprintf (dump_file, " to ");
7023 print_generic_expr (dump_file, val, 0);
7024 fprintf (dump_file, "\n");
7027 if (is_gimple_assign (stmt))
7028 gimple_assign_set_rhs_from_tree (si, val);
7031 gcc_assert (gimple_code (stmt) == GIMPLE_COND);
7032 if (integer_zerop (val))
7033 gimple_cond_make_false (stmt);
7034 else if (integer_onep (val))
7035 gimple_cond_make_true (stmt);
7046 /* Callback for substitute_and_fold folding the stmt at *SI. */
7049 vrp_fold_stmt (gimple_stmt_iterator *si)
7051 if (fold_predicate_in (si))
7054 return simplify_stmt_using_ranges (si);
7057 /* Stack of dest,src equivalency pairs that need to be restored after
7058 each attempt to thread a block's incoming edge to an outgoing edge.
7060 A NULL entry is used to mark the end of pairs which need to be
7062 static VEC(tree,heap) *stack;
7064 /* A trivial wrapper so that we can present the generic jump threading
7065 code with a simple API for simplifying statements. STMT is the
7066 statement we want to simplify, WITHIN_STMT provides the location
7067 for any overflow warnings. */
7070 simplify_stmt_for_jump_threading (gimple stmt, gimple within_stmt)
7072 /* We only use VRP information to simplify conditionals. This is
7073 overly conservative, but it's unclear if doing more would be
7074 worth the compile time cost. */
7075 if (gimple_code (stmt) != GIMPLE_COND)
7078 return vrp_evaluate_conditional (gimple_cond_code (stmt),
7079 gimple_cond_lhs (stmt),
7080 gimple_cond_rhs (stmt), within_stmt);
7083 /* Blocks which have more than one predecessor and more than
7084 one successor present jump threading opportunities, i.e.,
7085 when the block is reached from a specific predecessor, we
7086 may be able to determine which of the outgoing edges will
7087 be traversed. When this optimization applies, we are able
7088 to avoid conditionals at runtime and we may expose secondary
7089 optimization opportunities.
7091 This routine is effectively a driver for the generic jump
7092 threading code. It basically just presents the generic code
7093 with edges that may be suitable for jump threading.
7095 Unlike DOM, we do not iterate VRP if jump threading was successful.
7096 While iterating may expose new opportunities for VRP, it is expected
7097 those opportunities would be very limited and the compile time cost
7098 to expose those opportunities would be significant.
7100 As jump threading opportunities are discovered, they are registered
7101 for later realization. */
7104 identify_jump_threads (void)
7111 /* Ugh. When substituting values earlier in this pass we can
7112 wipe the dominance information. So rebuild the dominator
7113 information as we need it within the jump threading code. */
7114 calculate_dominance_info (CDI_DOMINATORS);
7116 /* We do not allow VRP information to be used for jump threading
7117 across a back edge in the CFG. Otherwise it becomes too
7118 difficult to avoid eliminating loop exit tests. Of course
7119 EDGE_DFS_BACK is not accurate at this time so we have to
7121 mark_dfs_back_edges ();
7123 /* Do not thread across edges we are about to remove. Just marking
7124 them as EDGE_DFS_BACK will do. */
7125 for (i = 0; VEC_iterate (edge, to_remove_edges, i, e); ++i)
7126 e->flags |= EDGE_DFS_BACK;
7128 /* Allocate our unwinder stack to unwind any temporary equivalences
7129 that might be recorded. */
7130 stack = VEC_alloc (tree, heap, 20);
7132 /* To avoid lots of silly node creation, we create a single
7133 conditional and just modify it in-place when attempting to
7135 dummy = gimple_build_cond (EQ_EXPR,
7136 integer_zero_node, integer_zero_node,
7139 /* Walk through all the blocks finding those which present a
7140 potential jump threading opportunity. We could set this up
7141 as a dominator walker and record data during the walk, but
7142 I doubt it's worth the effort for the classes of jump
7143 threading opportunities we are trying to identify at this
7144 point in compilation. */
7149 /* If the generic jump threading code does not find this block
7150 interesting, then there is nothing to do. */
7151 if (! potentially_threadable_block (bb))
7154 /* We only care about blocks ending in a COND_EXPR. While there
7155 may be some value in handling SWITCH_EXPR here, I doubt it's
7156 terribly important. */
7157 last = gsi_stmt (gsi_last_bb (bb));
7158 if (gimple_code (last) != GIMPLE_COND)
7161 /* We're basically looking for any kind of conditional with
7162 integral type arguments. */
7163 if (TREE_CODE (gimple_cond_lhs (last)) == SSA_NAME
7164 && INTEGRAL_TYPE_P (TREE_TYPE (gimple_cond_lhs (last)))
7165 && (TREE_CODE (gimple_cond_rhs (last)) == SSA_NAME
7166 || is_gimple_min_invariant (gimple_cond_rhs (last)))
7167 && INTEGRAL_TYPE_P (TREE_TYPE (gimple_cond_rhs (last))))
7171 /* We've got a block with multiple predecessors and multiple
7172 successors which also ends in a suitable conditional. For
7173 each predecessor, see if we can thread it to a specific
7175 FOR_EACH_EDGE (e, ei, bb->preds)
7177 /* Do not thread across back edges or abnormal edges
7179 if (e->flags & (EDGE_DFS_BACK | EDGE_COMPLEX))
7182 thread_across_edge (dummy, e, true, &stack,
7183 simplify_stmt_for_jump_threading);
7188 /* We do not actually update the CFG or SSA graphs at this point as
7189 ASSERT_EXPRs are still in the IL and cfg cleanup code does not yet
7190 handle ASSERT_EXPRs gracefully. */
7193 /* We identified all the jump threading opportunities earlier, but could
7194 not transform the CFG at that time. This routine transforms the
7195 CFG and arranges for the dominator tree to be rebuilt if necessary.
7197 Note the SSA graph update will occur during the normal TODO
7198 processing by the pass manager. */
7200 finalize_jump_threads (void)
7202 thread_through_all_blocks (false);
7203 VEC_free (tree, heap, stack);
7207 /* Traverse all the blocks folding conditionals with known ranges. */
7213 prop_value_t *single_val_range;
7214 bool do_value_subst_p;
7218 fprintf (dump_file, "\nValue ranges after VRP:\n\n");
7219 dump_all_value_ranges (dump_file);
7220 fprintf (dump_file, "\n");
7223 /* We may have ended with ranges that have exactly one value. Those
7224 values can be substituted as any other const propagated
7225 value using substitute_and_fold. */
7226 single_val_range = XCNEWVEC (prop_value_t, num_ssa_names);
7228 do_value_subst_p = false;
7229 for (i = 0; i < num_ssa_names; i++)
7231 && vr_value[i]->type == VR_RANGE
7232 && vr_value[i]->min == vr_value[i]->max
7233 && is_gimple_min_invariant (vr_value[i]->min))
7235 single_val_range[i].value = vr_value[i]->min;
7236 do_value_subst_p = true;
7239 if (!do_value_subst_p)
7241 /* We found no single-valued ranges, don't waste time trying to
7242 do single value substitution in substitute_and_fold. */
7243 free (single_val_range);
7244 single_val_range = NULL;
7247 substitute_and_fold (single_val_range, vrp_fold_stmt);
7249 if (warn_array_bounds)
7250 check_all_array_refs ();
7252 /* We must identify jump threading opportunities before we release
7253 the datastructures built by VRP. */
7254 identify_jump_threads ();
7256 /* Free allocated memory. */
7257 for (i = 0; i < num_ssa_names; i++)
7260 BITMAP_FREE (vr_value[i]->equiv);
7264 free (single_val_range);
7266 free (vr_phi_edge_counts);
7268 /* So that we can distinguish between VRP data being available
7269 and not available. */
7271 vr_phi_edge_counts = NULL;
7275 /* Main entry point to VRP (Value Range Propagation). This pass is
7276 loosely based on J. R. C. Patterson, ``Accurate Static Branch
7277 Prediction by Value Range Propagation,'' in SIGPLAN Conference on
7278 Programming Language Design and Implementation, pp. 67-78, 1995.
7279 Also available at http://citeseer.ist.psu.edu/patterson95accurate.html
7281 This is essentially an SSA-CCP pass modified to deal with ranges
7282 instead of constants.
7284 While propagating ranges, we may find that two or more SSA name
7285 have equivalent, though distinct ranges. For instance,
7288 2 p_4 = ASSERT_EXPR <p_3, p_3 != 0>
7290 4 p_5 = ASSERT_EXPR <p_4, p_4 == q_2>;
7294 In the code above, pointer p_5 has range [q_2, q_2], but from the
7295 code we can also determine that p_5 cannot be NULL and, if q_2 had
7296 a non-varying range, p_5's range should also be compatible with it.
7298 These equivalences are created by two expressions: ASSERT_EXPR and
7299 copy operations. Since p_5 is an assertion on p_4, and p_4 was the
7300 result of another assertion, then we can use the fact that p_5 and
7301 p_4 are equivalent when evaluating p_5's range.
7303 Together with value ranges, we also propagate these equivalences
7304 between names so that we can take advantage of information from
7305 multiple ranges when doing final replacement. Note that this
7306 equivalency relation is transitive but not symmetric.
7308 In the example above, p_5 is equivalent to p_4, q_2 and p_3, but we
7309 cannot assert that q_2 is equivalent to p_5 because q_2 may be used
7310 in contexts where that assertion does not hold (e.g., in line 6).
7312 TODO, the main difference between this pass and Patterson's is that
7313 we do not propagate edge probabilities. We only compute whether
7314 edges can be taken or not. That is, instead of having a spectrum
7315 of jump probabilities between 0 and 1, we only deal with 0, 1 and
7316 DON'T KNOW. In the future, it may be worthwhile to propagate
7317 probabilities to aid branch prediction. */
7326 loop_optimizer_init (LOOPS_NORMAL | LOOPS_HAVE_RECORDED_EXITS);
7327 rewrite_into_loop_closed_ssa (NULL, TODO_update_ssa);
7330 insert_range_assertions ();
7332 to_remove_edges = VEC_alloc (edge, heap, 10);
7333 to_update_switch_stmts = VEC_alloc (switch_update, heap, 5);
7334 threadedge_initialize_values ();
7337 ssa_propagate (vrp_visit_stmt, vrp_visit_phi_node);
7340 /* ASSERT_EXPRs must be removed before finalizing jump threads
7341 as finalizing jump threads calls the CFG cleanup code which
7342 does not properly handle ASSERT_EXPRs. */
7343 remove_range_assertions ();
7345 /* If we exposed any new variables, go ahead and put them into
7346 SSA form now, before we handle jump threading. This simplifies
7347 interactions between rewriting of _DECL nodes into SSA form
7348 and rewriting SSA_NAME nodes into SSA form after block
7349 duplication and CFG manipulation. */
7350 update_ssa (TODO_update_ssa);
7352 finalize_jump_threads ();
7354 /* Remove dead edges from SWITCH_EXPR optimization. This leaves the
7355 CFG in a broken state and requires a cfg_cleanup run. */
7356 for (i = 0; VEC_iterate (edge, to_remove_edges, i, e); ++i)
7358 /* Update SWITCH_EXPR case label vector. */
7359 for (i = 0; VEC_iterate (switch_update, to_update_switch_stmts, i, su); ++i)
7362 size_t n = TREE_VEC_LENGTH (su->vec);
7364 gimple_switch_set_num_labels (su->stmt, n);
7365 for (j = 0; j < n; j++)
7366 gimple_switch_set_label (su->stmt, j, TREE_VEC_ELT (su->vec, j));
7367 /* As we may have replaced the default label with a regular one
7368 make sure to make it a real default label again. This ensures
7369 optimal expansion. */
7370 label = gimple_switch_default_label (su->stmt);
7371 CASE_LOW (label) = NULL_TREE;
7372 CASE_HIGH (label) = NULL_TREE;
7375 if (VEC_length (edge, to_remove_edges) > 0)
7376 free_dominance_info (CDI_DOMINATORS);
7378 VEC_free (edge, heap, to_remove_edges);
7379 VEC_free (switch_update, heap, to_update_switch_stmts);
7380 threadedge_finalize_values ();
7383 loop_optimizer_finalize ();
7390 return flag_tree_vrp != 0;
7393 struct gimple_opt_pass pass_vrp =
7398 gate_vrp, /* gate */
7399 execute_vrp, /* execute */
7402 0, /* static_pass_number */
7403 TV_TREE_VRP, /* tv_id */
7404 PROP_ssa, /* properties_required */
7405 0, /* properties_provided */
7406 0, /* properties_destroyed */
7407 0, /* todo_flags_start */
7412 | TODO_update_ssa /* todo_flags_finish */