1 /* Support routines for Value Range Propagation (VRP).
2 Copyright (C) 2005, 2006, 2007, 2008, 2009 Free Software Foundation, Inc.
3 Contributed by Diego Novillo <dnovillo@redhat.com>.
5 This file is part of GCC.
7 GCC is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 3, or (at your option)
12 GCC is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with GCC; see the file COPYING3. If not see
19 <http://www.gnu.org/licenses/>. */
23 #include "coretypes.h"
28 #include "basic-block.h"
29 #include "tree-flow.h"
30 #include "tree-pass.h"
31 #include "tree-dump.h"
33 #include "diagnostic.h"
37 #include "tree-scalar-evolution.h"
38 #include "tree-ssa-propagate.h"
39 #include "tree-chrec.h"
42 /* Set of SSA names found live during the RPO traversal of the function
43 for still active basic-blocks. */
46 /* Return true if the SSA name NAME is live on the edge E. */
49 live_on_edge (edge e, tree name)
51 return (live[e->dest->index]
52 && TEST_BIT (live[e->dest->index], SSA_NAME_VERSION (name)));
55 /* Local functions. */
56 static int compare_values (tree val1, tree val2);
57 static int compare_values_warnv (tree val1, tree val2, bool *);
58 static void vrp_meet (value_range_t *, value_range_t *);
59 static tree vrp_evaluate_conditional_warnv_with_ops (enum tree_code,
60 tree, tree, bool, bool *,
63 /* Location information for ASSERT_EXPRs. Each instance of this
64 structure describes an ASSERT_EXPR for an SSA name. Since a single
65 SSA name may have more than one assertion associated with it, these
66 locations are kept in a linked list attached to the corresponding
70 /* Basic block where the assertion would be inserted. */
73 /* Some assertions need to be inserted on an edge (e.g., assertions
74 generated by COND_EXPRs). In those cases, BB will be NULL. */
77 /* Pointer to the statement that generated this assertion. */
78 gimple_stmt_iterator si;
80 /* Predicate code for the ASSERT_EXPR. Must be COMPARISON_CLASS_P. */
81 enum tree_code comp_code;
83 /* Value being compared against. */
86 /* Expression to compare. */
89 /* Next node in the linked list. */
90 struct assert_locus_d *next;
93 typedef struct assert_locus_d *assert_locus_t;
95 /* If bit I is present, it means that SSA name N_i has a list of
96 assertions that should be inserted in the IL. */
97 static bitmap need_assert_for;
99 /* Array of locations lists where to insert assertions. ASSERTS_FOR[I]
100 holds a list of ASSERT_LOCUS_T nodes that describe where
101 ASSERT_EXPRs for SSA name N_I should be inserted. */
102 static assert_locus_t *asserts_for;
104 /* Value range array. After propagation, VR_VALUE[I] holds the range
105 of values that SSA name N_I may take. */
106 static value_range_t **vr_value;
108 /* For a PHI node which sets SSA name N_I, VR_COUNTS[I] holds the
109 number of executable edges we saw the last time we visited the
111 static int *vr_phi_edge_counts;
118 static VEC (edge, heap) *to_remove_edges;
119 DEF_VEC_O(switch_update);
120 DEF_VEC_ALLOC_O(switch_update, heap);
121 static VEC (switch_update, heap) *to_update_switch_stmts;
124 /* Return the maximum value for TYPE. */
127 vrp_val_max (const_tree type)
129 if (!INTEGRAL_TYPE_P (type))
132 return TYPE_MAX_VALUE (type);
135 /* Return the minimum value for TYPE. */
138 vrp_val_min (const_tree type)
140 if (!INTEGRAL_TYPE_P (type))
143 return TYPE_MIN_VALUE (type);
146 /* Return whether VAL is equal to the maximum value of its type. This
147 will be true for a positive overflow infinity. We can't do a
148 simple equality comparison with TYPE_MAX_VALUE because C typedefs
149 and Ada subtypes can produce types whose TYPE_MAX_VALUE is not ==
150 to the integer constant with the same value in the type. */
153 vrp_val_is_max (const_tree val)
155 tree type_max = vrp_val_max (TREE_TYPE (val));
156 return (val == type_max
157 || (type_max != NULL_TREE
158 && operand_equal_p (val, type_max, 0)));
161 /* Return whether VAL is equal to the minimum value of its type. This
162 will be true for a negative overflow infinity. */
165 vrp_val_is_min (const_tree val)
167 tree type_min = vrp_val_min (TREE_TYPE (val));
168 return (val == type_min
169 || (type_min != NULL_TREE
170 && operand_equal_p (val, type_min, 0)));
174 /* Return whether TYPE should use an overflow infinity distinct from
175 TYPE_{MIN,MAX}_VALUE. We use an overflow infinity value to
176 represent a signed overflow during VRP computations. An infinity
177 is distinct from a half-range, which will go from some number to
178 TYPE_{MIN,MAX}_VALUE. */
181 needs_overflow_infinity (const_tree type)
183 return INTEGRAL_TYPE_P (type) && !TYPE_OVERFLOW_WRAPS (type);
186 /* Return whether TYPE can support our overflow infinity
187 representation: we use the TREE_OVERFLOW flag, which only exists
188 for constants. If TYPE doesn't support this, we don't optimize
189 cases which would require signed overflow--we drop them to
193 supports_overflow_infinity (const_tree type)
195 tree min = vrp_val_min (type), max = vrp_val_max (type);
196 #ifdef ENABLE_CHECKING
197 gcc_assert (needs_overflow_infinity (type));
199 return (min != NULL_TREE
200 && CONSTANT_CLASS_P (min)
202 && CONSTANT_CLASS_P (max));
205 /* VAL is the maximum or minimum value of a type. Return a
206 corresponding overflow infinity. */
209 make_overflow_infinity (tree val)
211 #ifdef ENABLE_CHECKING
212 gcc_assert (val != NULL_TREE && CONSTANT_CLASS_P (val));
214 val = copy_node (val);
215 TREE_OVERFLOW (val) = 1;
219 /* Return a negative overflow infinity for TYPE. */
222 negative_overflow_infinity (tree type)
224 #ifdef ENABLE_CHECKING
225 gcc_assert (supports_overflow_infinity (type));
227 return make_overflow_infinity (vrp_val_min (type));
230 /* Return a positive overflow infinity for TYPE. */
233 positive_overflow_infinity (tree type)
235 #ifdef ENABLE_CHECKING
236 gcc_assert (supports_overflow_infinity (type));
238 return make_overflow_infinity (vrp_val_max (type));
241 /* Return whether VAL is a negative overflow infinity. */
244 is_negative_overflow_infinity (const_tree val)
246 return (needs_overflow_infinity (TREE_TYPE (val))
247 && CONSTANT_CLASS_P (val)
248 && TREE_OVERFLOW (val)
249 && vrp_val_is_min (val));
252 /* Return whether VAL is a positive overflow infinity. */
255 is_positive_overflow_infinity (const_tree val)
257 return (needs_overflow_infinity (TREE_TYPE (val))
258 && CONSTANT_CLASS_P (val)
259 && TREE_OVERFLOW (val)
260 && vrp_val_is_max (val));
263 /* Return whether VAL is a positive or negative overflow infinity. */
266 is_overflow_infinity (const_tree val)
268 return (needs_overflow_infinity (TREE_TYPE (val))
269 && CONSTANT_CLASS_P (val)
270 && TREE_OVERFLOW (val)
271 && (vrp_val_is_min (val) || vrp_val_is_max (val)));
274 /* Return whether STMT has a constant rhs that is_overflow_infinity. */
277 stmt_overflow_infinity (gimple stmt)
279 if (is_gimple_assign (stmt)
280 && get_gimple_rhs_class (gimple_assign_rhs_code (stmt)) ==
282 return is_overflow_infinity (gimple_assign_rhs1 (stmt));
286 /* If VAL is now an overflow infinity, return VAL. Otherwise, return
287 the same value with TREE_OVERFLOW clear. This can be used to avoid
288 confusing a regular value with an overflow value. */
291 avoid_overflow_infinity (tree val)
293 if (!is_overflow_infinity (val))
296 if (vrp_val_is_max (val))
297 return vrp_val_max (TREE_TYPE (val));
300 #ifdef ENABLE_CHECKING
301 gcc_assert (vrp_val_is_min (val));
303 return vrp_val_min (TREE_TYPE (val));
308 /* Return true if ARG is marked with the nonnull attribute in the
309 current function signature. */
312 nonnull_arg_p (const_tree arg)
314 tree t, attrs, fntype;
315 unsigned HOST_WIDE_INT arg_num;
317 gcc_assert (TREE_CODE (arg) == PARM_DECL && POINTER_TYPE_P (TREE_TYPE (arg)));
319 /* The static chain decl is always non null. */
320 if (arg == cfun->static_chain_decl)
323 fntype = TREE_TYPE (current_function_decl);
324 attrs = lookup_attribute ("nonnull", TYPE_ATTRIBUTES (fntype));
326 /* If "nonnull" wasn't specified, we know nothing about the argument. */
327 if (attrs == NULL_TREE)
330 /* If "nonnull" applies to all the arguments, then ARG is non-null. */
331 if (TREE_VALUE (attrs) == NULL_TREE)
334 /* Get the position number for ARG in the function signature. */
335 for (arg_num = 1, t = DECL_ARGUMENTS (current_function_decl);
337 t = TREE_CHAIN (t), arg_num++)
343 gcc_assert (t == arg);
345 /* Now see if ARG_NUM is mentioned in the nonnull list. */
346 for (t = TREE_VALUE (attrs); t; t = TREE_CHAIN (t))
348 if (compare_tree_int (TREE_VALUE (t), arg_num) == 0)
356 /* Set value range VR to VR_VARYING. */
359 set_value_range_to_varying (value_range_t *vr)
361 vr->type = VR_VARYING;
362 vr->min = vr->max = NULL_TREE;
364 bitmap_clear (vr->equiv);
368 /* Set value range VR to {T, MIN, MAX, EQUIV}. */
371 set_value_range (value_range_t *vr, enum value_range_type t, tree min,
372 tree max, bitmap equiv)
374 #if defined ENABLE_CHECKING
375 /* Check the validity of the range. */
376 if (t == VR_RANGE || t == VR_ANTI_RANGE)
380 gcc_assert (min && max);
382 if (INTEGRAL_TYPE_P (TREE_TYPE (min)) && t == VR_ANTI_RANGE)
383 gcc_assert (!vrp_val_is_min (min) || !vrp_val_is_max (max));
385 cmp = compare_values (min, max);
386 gcc_assert (cmp == 0 || cmp == -1 || cmp == -2);
388 if (needs_overflow_infinity (TREE_TYPE (min)))
389 gcc_assert (!is_overflow_infinity (min)
390 || !is_overflow_infinity (max));
393 if (t == VR_UNDEFINED || t == VR_VARYING)
394 gcc_assert (min == NULL_TREE && max == NULL_TREE);
396 if (t == VR_UNDEFINED || t == VR_VARYING)
397 gcc_assert (equiv == NULL || bitmap_empty_p (equiv));
404 /* Since updating the equivalence set involves deep copying the
405 bitmaps, only do it if absolutely necessary. */
406 if (vr->equiv == NULL
408 vr->equiv = BITMAP_ALLOC (NULL);
410 if (equiv != vr->equiv)
412 if (equiv && !bitmap_empty_p (equiv))
413 bitmap_copy (vr->equiv, equiv);
415 bitmap_clear (vr->equiv);
420 /* Set value range VR to the canonical form of {T, MIN, MAX, EQUIV}.
421 This means adjusting T, MIN and MAX representing the case of a
422 wrapping range with MAX < MIN covering [MIN, type_max] U [type_min, MAX]
423 as anti-rage ~[MAX+1, MIN-1]. Likewise for wrapping anti-ranges.
424 In corner cases where MAX+1 or MIN-1 wraps this will fall back
426 This routine exists to ease canonicalization in the case where we
427 extract ranges from var + CST op limit. */
430 set_and_canonicalize_value_range (value_range_t *vr, enum value_range_type t,
431 tree min, tree max, bitmap equiv)
433 /* Nothing to canonicalize for symbolic or unknown or varying ranges. */
435 && t != VR_ANTI_RANGE)
436 || TREE_CODE (min) != INTEGER_CST
437 || TREE_CODE (max) != INTEGER_CST)
439 set_value_range (vr, t, min, max, equiv);
443 /* Wrong order for min and max, to swap them and the VR type we need
445 if (tree_int_cst_lt (max, min))
447 tree one = build_int_cst (TREE_TYPE (min), 1);
448 tree tmp = int_const_binop (PLUS_EXPR, max, one, 0);
449 max = int_const_binop (MINUS_EXPR, min, one, 0);
452 /* There's one corner case, if we had [C+1, C] before we now have
453 that again. But this represents an empty value range, so drop
454 to varying in this case. */
455 if (tree_int_cst_lt (max, min))
457 set_value_range_to_varying (vr);
461 t = t == VR_RANGE ? VR_ANTI_RANGE : VR_RANGE;
464 /* Anti-ranges that can be represented as ranges should be so. */
465 if (t == VR_ANTI_RANGE)
467 bool is_min = vrp_val_is_min (min);
468 bool is_max = vrp_val_is_max (max);
470 if (is_min && is_max)
472 /* We cannot deal with empty ranges, drop to varying. */
473 set_value_range_to_varying (vr);
477 /* As a special exception preserve non-null ranges. */
478 && !(TYPE_UNSIGNED (TREE_TYPE (min))
479 && integer_zerop (max)))
481 tree one = build_int_cst (TREE_TYPE (max), 1);
482 min = int_const_binop (PLUS_EXPR, max, one, 0);
483 max = vrp_val_max (TREE_TYPE (max));
488 tree one = build_int_cst (TREE_TYPE (min), 1);
489 max = int_const_binop (MINUS_EXPR, min, one, 0);
490 min = vrp_val_min (TREE_TYPE (min));
495 set_value_range (vr, t, min, max, equiv);
498 /* Copy value range FROM into value range TO. */
501 copy_value_range (value_range_t *to, value_range_t *from)
503 set_value_range (to, from->type, from->min, from->max, from->equiv);
506 /* Set value range VR to a single value. This function is only called
507 with values we get from statements, and exists to clear the
508 TREE_OVERFLOW flag so that we don't think we have an overflow
509 infinity when we shouldn't. */
512 set_value_range_to_value (value_range_t *vr, tree val, bitmap equiv)
514 gcc_assert (is_gimple_min_invariant (val));
515 val = avoid_overflow_infinity (val);
516 set_value_range (vr, VR_RANGE, val, val, equiv);
519 /* Set value range VR to a non-negative range of type TYPE.
520 OVERFLOW_INFINITY indicates whether to use an overflow infinity
521 rather than TYPE_MAX_VALUE; this should be true if we determine
522 that the range is nonnegative based on the assumption that signed
523 overflow does not occur. */
526 set_value_range_to_nonnegative (value_range_t *vr, tree type,
527 bool overflow_infinity)
531 if (overflow_infinity && !supports_overflow_infinity (type))
533 set_value_range_to_varying (vr);
537 zero = build_int_cst (type, 0);
538 set_value_range (vr, VR_RANGE, zero,
540 ? positive_overflow_infinity (type)
541 : TYPE_MAX_VALUE (type)),
545 /* Set value range VR to a non-NULL range of type TYPE. */
548 set_value_range_to_nonnull (value_range_t *vr, tree type)
550 tree zero = build_int_cst (type, 0);
551 set_value_range (vr, VR_ANTI_RANGE, zero, zero, vr->equiv);
555 /* Set value range VR to a NULL range of type TYPE. */
558 set_value_range_to_null (value_range_t *vr, tree type)
560 set_value_range_to_value (vr, build_int_cst (type, 0), vr->equiv);
564 /* Set value range VR to a range of a truthvalue of type TYPE. */
567 set_value_range_to_truthvalue (value_range_t *vr, tree type)
569 if (TYPE_PRECISION (type) == 1)
570 set_value_range_to_varying (vr);
572 set_value_range (vr, VR_RANGE,
573 build_int_cst (type, 0), build_int_cst (type, 1),
578 /* Set value range VR to VR_UNDEFINED. */
581 set_value_range_to_undefined (value_range_t *vr)
583 vr->type = VR_UNDEFINED;
584 vr->min = vr->max = NULL_TREE;
586 bitmap_clear (vr->equiv);
590 /* If abs (min) < abs (max), set VR to [-max, max], if
591 abs (min) >= abs (max), set VR to [-min, min]. */
594 abs_extent_range (value_range_t *vr, tree min, tree max)
598 gcc_assert (TREE_CODE (min) == INTEGER_CST);
599 gcc_assert (TREE_CODE (max) == INTEGER_CST);
600 gcc_assert (INTEGRAL_TYPE_P (TREE_TYPE (min)));
601 gcc_assert (!TYPE_UNSIGNED (TREE_TYPE (min)));
602 min = fold_unary (ABS_EXPR, TREE_TYPE (min), min);
603 max = fold_unary (ABS_EXPR, TREE_TYPE (max), max);
604 if (TREE_OVERFLOW (min) || TREE_OVERFLOW (max))
606 set_value_range_to_varying (vr);
609 cmp = compare_values (min, max);
611 min = fold_unary (NEGATE_EXPR, TREE_TYPE (min), max);
612 else if (cmp == 0 || cmp == 1)
615 min = fold_unary (NEGATE_EXPR, TREE_TYPE (min), min);
619 set_value_range_to_varying (vr);
622 set_and_canonicalize_value_range (vr, VR_RANGE, min, max, NULL);
626 /* Return value range information for VAR.
628 If we have no values ranges recorded (ie, VRP is not running), then
629 return NULL. Otherwise create an empty range if none existed for VAR. */
631 static value_range_t *
632 get_value_range (const_tree var)
636 unsigned ver = SSA_NAME_VERSION (var);
638 /* If we have no recorded ranges, then return NULL. */
646 /* Create a default value range. */
647 vr_value[ver] = vr = XCNEW (value_range_t);
649 /* Defer allocating the equivalence set. */
652 /* If VAR is a default definition, the variable can take any value
654 sym = SSA_NAME_VAR (var);
655 if (SSA_NAME_IS_DEFAULT_DEF (var))
657 /* Try to use the "nonnull" attribute to create ~[0, 0]
658 anti-ranges for pointers. Note that this is only valid with
659 default definitions of PARM_DECLs. */
660 if (TREE_CODE (sym) == PARM_DECL
661 && POINTER_TYPE_P (TREE_TYPE (sym))
662 && nonnull_arg_p (sym))
663 set_value_range_to_nonnull (vr, TREE_TYPE (sym));
665 set_value_range_to_varying (vr);
671 /* Return true, if VAL1 and VAL2 are equal values for VRP purposes. */
674 vrp_operand_equal_p (const_tree val1, const_tree val2)
678 if (!val1 || !val2 || !operand_equal_p (val1, val2, 0))
680 if (is_overflow_infinity (val1))
681 return is_overflow_infinity (val2);
685 /* Return true, if the bitmaps B1 and B2 are equal. */
688 vrp_bitmap_equal_p (const_bitmap b1, const_bitmap b2)
692 && bitmap_equal_p (b1, b2)));
695 /* Update the value range and equivalence set for variable VAR to
696 NEW_VR. Return true if NEW_VR is different from VAR's previous
699 NOTE: This function assumes that NEW_VR is a temporary value range
700 object created for the sole purpose of updating VAR's range. The
701 storage used by the equivalence set from NEW_VR will be freed by
702 this function. Do not call update_value_range when NEW_VR
703 is the range object associated with another SSA name. */
706 update_value_range (const_tree var, value_range_t *new_vr)
708 value_range_t *old_vr;
711 /* Update the value range, if necessary. */
712 old_vr = get_value_range (var);
713 is_new = old_vr->type != new_vr->type
714 || !vrp_operand_equal_p (old_vr->min, new_vr->min)
715 || !vrp_operand_equal_p (old_vr->max, new_vr->max)
716 || !vrp_bitmap_equal_p (old_vr->equiv, new_vr->equiv);
719 set_value_range (old_vr, new_vr->type, new_vr->min, new_vr->max,
722 BITMAP_FREE (new_vr->equiv);
728 /* Add VAR and VAR's equivalence set to EQUIV. This is the central
729 point where equivalence processing can be turned on/off. */
732 add_equivalence (bitmap *equiv, const_tree var)
734 unsigned ver = SSA_NAME_VERSION (var);
735 value_range_t *vr = vr_value[ver];
738 *equiv = BITMAP_ALLOC (NULL);
739 bitmap_set_bit (*equiv, ver);
741 bitmap_ior_into (*equiv, vr->equiv);
745 /* Return true if VR is ~[0, 0]. */
748 range_is_nonnull (value_range_t *vr)
750 return vr->type == VR_ANTI_RANGE
751 && integer_zerop (vr->min)
752 && integer_zerop (vr->max);
756 /* Return true if VR is [0, 0]. */
759 range_is_null (value_range_t *vr)
761 return vr->type == VR_RANGE
762 && integer_zerop (vr->min)
763 && integer_zerop (vr->max);
767 /* Return true if value range VR involves at least one symbol. */
770 symbolic_range_p (value_range_t *vr)
772 return (!is_gimple_min_invariant (vr->min)
773 || !is_gimple_min_invariant (vr->max));
776 /* Return true if value range VR uses an overflow infinity. */
779 overflow_infinity_range_p (value_range_t *vr)
781 return (vr->type == VR_RANGE
782 && (is_overflow_infinity (vr->min)
783 || is_overflow_infinity (vr->max)));
786 /* Return false if we can not make a valid comparison based on VR;
787 this will be the case if it uses an overflow infinity and overflow
788 is not undefined (i.e., -fno-strict-overflow is in effect).
789 Otherwise return true, and set *STRICT_OVERFLOW_P to true if VR
790 uses an overflow infinity. */
793 usable_range_p (value_range_t *vr, bool *strict_overflow_p)
795 gcc_assert (vr->type == VR_RANGE);
796 if (is_overflow_infinity (vr->min))
798 *strict_overflow_p = true;
799 if (!TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (vr->min)))
802 if (is_overflow_infinity (vr->max))
804 *strict_overflow_p = true;
805 if (!TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (vr->max)))
812 /* Like tree_expr_nonnegative_warnv_p, but this function uses value
813 ranges obtained so far. */
816 vrp_expr_computes_nonnegative (tree expr, bool *strict_overflow_p)
818 return (tree_expr_nonnegative_warnv_p (expr, strict_overflow_p)
819 || (TREE_CODE (expr) == SSA_NAME
820 && ssa_name_nonnegative_p (expr)));
823 /* Return true if the result of assignment STMT is know to be non-negative.
824 If the return value is based on the assumption that signed overflow is
825 undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't change
826 *STRICT_OVERFLOW_P.*/
829 gimple_assign_nonnegative_warnv_p (gimple stmt, bool *strict_overflow_p)
831 enum tree_code code = gimple_assign_rhs_code (stmt);
832 switch (get_gimple_rhs_class (code))
834 case GIMPLE_UNARY_RHS:
835 return tree_unary_nonnegative_warnv_p (gimple_assign_rhs_code (stmt),
836 gimple_expr_type (stmt),
837 gimple_assign_rhs1 (stmt),
839 case GIMPLE_BINARY_RHS:
840 return tree_binary_nonnegative_warnv_p (gimple_assign_rhs_code (stmt),
841 gimple_expr_type (stmt),
842 gimple_assign_rhs1 (stmt),
843 gimple_assign_rhs2 (stmt),
845 case GIMPLE_SINGLE_RHS:
846 return tree_single_nonnegative_warnv_p (gimple_assign_rhs1 (stmt),
848 case GIMPLE_INVALID_RHS:
855 /* Return true if return value of call STMT is know to be non-negative.
856 If the return value is based on the assumption that signed overflow is
857 undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't change
858 *STRICT_OVERFLOW_P.*/
861 gimple_call_nonnegative_warnv_p (gimple stmt, bool *strict_overflow_p)
863 tree arg0 = gimple_call_num_args (stmt) > 0 ?
864 gimple_call_arg (stmt, 0) : NULL_TREE;
865 tree arg1 = gimple_call_num_args (stmt) > 1 ?
866 gimple_call_arg (stmt, 1) : NULL_TREE;
868 return tree_call_nonnegative_warnv_p (gimple_expr_type (stmt),
869 gimple_call_fndecl (stmt),
875 /* Return true if STMT is know to to compute a non-negative value.
876 If the return value is based on the assumption that signed overflow is
877 undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't change
878 *STRICT_OVERFLOW_P.*/
881 gimple_stmt_nonnegative_warnv_p (gimple stmt, bool *strict_overflow_p)
883 switch (gimple_code (stmt))
886 return gimple_assign_nonnegative_warnv_p (stmt, strict_overflow_p);
888 return gimple_call_nonnegative_warnv_p (stmt, strict_overflow_p);
894 /* Return true if the result of assignment STMT is know to be non-zero.
895 If the return value is based on the assumption that signed overflow is
896 undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't change
897 *STRICT_OVERFLOW_P.*/
900 gimple_assign_nonzero_warnv_p (gimple stmt, bool *strict_overflow_p)
902 enum tree_code code = gimple_assign_rhs_code (stmt);
903 switch (get_gimple_rhs_class (code))
905 case GIMPLE_UNARY_RHS:
906 return tree_unary_nonzero_warnv_p (gimple_assign_rhs_code (stmt),
907 gimple_expr_type (stmt),
908 gimple_assign_rhs1 (stmt),
910 case GIMPLE_BINARY_RHS:
911 return tree_binary_nonzero_warnv_p (gimple_assign_rhs_code (stmt),
912 gimple_expr_type (stmt),
913 gimple_assign_rhs1 (stmt),
914 gimple_assign_rhs2 (stmt),
916 case GIMPLE_SINGLE_RHS:
917 return tree_single_nonzero_warnv_p (gimple_assign_rhs1 (stmt),
919 case GIMPLE_INVALID_RHS:
926 /* Return true if STMT is know to to compute a non-zero value.
927 If the return value is based on the assumption that signed overflow is
928 undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't change
929 *STRICT_OVERFLOW_P.*/
932 gimple_stmt_nonzero_warnv_p (gimple stmt, bool *strict_overflow_p)
934 switch (gimple_code (stmt))
937 return gimple_assign_nonzero_warnv_p (stmt, strict_overflow_p);
939 return gimple_alloca_call_p (stmt);
945 /* Like tree_expr_nonzero_warnv_p, but this function uses value ranges
949 vrp_stmt_computes_nonzero (gimple stmt, bool *strict_overflow_p)
951 if (gimple_stmt_nonzero_warnv_p (stmt, strict_overflow_p))
954 /* If we have an expression of the form &X->a, then the expression
955 is nonnull if X is nonnull. */
956 if (is_gimple_assign (stmt)
957 && gimple_assign_rhs_code (stmt) == ADDR_EXPR)
959 tree expr = gimple_assign_rhs1 (stmt);
960 tree base = get_base_address (TREE_OPERAND (expr, 0));
962 if (base != NULL_TREE
963 && TREE_CODE (base) == INDIRECT_REF
964 && TREE_CODE (TREE_OPERAND (base, 0)) == SSA_NAME)
966 value_range_t *vr = get_value_range (TREE_OPERAND (base, 0));
967 if (range_is_nonnull (vr))
975 /* Returns true if EXPR is a valid value (as expected by compare_values) --
976 a gimple invariant, or SSA_NAME +- CST. */
979 valid_value_p (tree expr)
981 if (TREE_CODE (expr) == SSA_NAME)
984 if (TREE_CODE (expr) == PLUS_EXPR
985 || TREE_CODE (expr) == MINUS_EXPR)
986 return (TREE_CODE (TREE_OPERAND (expr, 0)) == SSA_NAME
987 && TREE_CODE (TREE_OPERAND (expr, 1)) == INTEGER_CST);
989 return is_gimple_min_invariant (expr);
995 -2 if those are incomparable. */
997 operand_less_p (tree val, tree val2)
999 /* LT is folded faster than GE and others. Inline the common case. */
1000 if (TREE_CODE (val) == INTEGER_CST && TREE_CODE (val2) == INTEGER_CST)
1002 if (TYPE_UNSIGNED (TREE_TYPE (val)))
1003 return INT_CST_LT_UNSIGNED (val, val2);
1006 if (INT_CST_LT (val, val2))
1014 fold_defer_overflow_warnings ();
1016 tcmp = fold_binary_to_constant (LT_EXPR, boolean_type_node, val, val2);
1018 fold_undefer_and_ignore_overflow_warnings ();
1021 || TREE_CODE (tcmp) != INTEGER_CST)
1024 if (!integer_zerop (tcmp))
1028 /* val >= val2, not considering overflow infinity. */
1029 if (is_negative_overflow_infinity (val))
1030 return is_negative_overflow_infinity (val2) ? 0 : 1;
1031 else if (is_positive_overflow_infinity (val2))
1032 return is_positive_overflow_infinity (val) ? 0 : 1;
1037 /* Compare two values VAL1 and VAL2. Return
1039 -2 if VAL1 and VAL2 cannot be compared at compile-time,
1042 +1 if VAL1 > VAL2, and
1045 This is similar to tree_int_cst_compare but supports pointer values
1046 and values that cannot be compared at compile time.
1048 If STRICT_OVERFLOW_P is not NULL, then set *STRICT_OVERFLOW_P to
1049 true if the return value is only valid if we assume that signed
1050 overflow is undefined. */
1053 compare_values_warnv (tree val1, tree val2, bool *strict_overflow_p)
1058 /* Below we rely on the fact that VAL1 and VAL2 are both pointers or
1060 gcc_assert (POINTER_TYPE_P (TREE_TYPE (val1))
1061 == POINTER_TYPE_P (TREE_TYPE (val2)));
1062 /* Convert the two values into the same type. This is needed because
1063 sizetype causes sign extension even for unsigned types. */
1064 val2 = fold_convert (TREE_TYPE (val1), val2);
1065 STRIP_USELESS_TYPE_CONVERSION (val2);
1067 if ((TREE_CODE (val1) == SSA_NAME
1068 || TREE_CODE (val1) == PLUS_EXPR
1069 || TREE_CODE (val1) == MINUS_EXPR)
1070 && (TREE_CODE (val2) == SSA_NAME
1071 || TREE_CODE (val2) == PLUS_EXPR
1072 || TREE_CODE (val2) == MINUS_EXPR))
1074 tree n1, c1, n2, c2;
1075 enum tree_code code1, code2;
1077 /* If VAL1 and VAL2 are of the form 'NAME [+-] CST' or 'NAME',
1078 return -1 or +1 accordingly. If VAL1 and VAL2 don't use the
1079 same name, return -2. */
1080 if (TREE_CODE (val1) == SSA_NAME)
1088 code1 = TREE_CODE (val1);
1089 n1 = TREE_OPERAND (val1, 0);
1090 c1 = TREE_OPERAND (val1, 1);
1091 if (tree_int_cst_sgn (c1) == -1)
1093 if (is_negative_overflow_infinity (c1))
1095 c1 = fold_unary_to_constant (NEGATE_EXPR, TREE_TYPE (c1), c1);
1098 code1 = code1 == MINUS_EXPR ? PLUS_EXPR : MINUS_EXPR;
1102 if (TREE_CODE (val2) == SSA_NAME)
1110 code2 = TREE_CODE (val2);
1111 n2 = TREE_OPERAND (val2, 0);
1112 c2 = TREE_OPERAND (val2, 1);
1113 if (tree_int_cst_sgn (c2) == -1)
1115 if (is_negative_overflow_infinity (c2))
1117 c2 = fold_unary_to_constant (NEGATE_EXPR, TREE_TYPE (c2), c2);
1120 code2 = code2 == MINUS_EXPR ? PLUS_EXPR : MINUS_EXPR;
1124 /* Both values must use the same name. */
1128 if (code1 == SSA_NAME
1129 && code2 == SSA_NAME)
1133 /* If overflow is defined we cannot simplify more. */
1134 if (!TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (val1)))
1137 if (strict_overflow_p != NULL
1138 && (code1 == SSA_NAME || !TREE_NO_WARNING (val1))
1139 && (code2 == SSA_NAME || !TREE_NO_WARNING (val2)))
1140 *strict_overflow_p = true;
1142 if (code1 == SSA_NAME)
1144 if (code2 == PLUS_EXPR)
1145 /* NAME < NAME + CST */
1147 else if (code2 == MINUS_EXPR)
1148 /* NAME > NAME - CST */
1151 else if (code1 == PLUS_EXPR)
1153 if (code2 == SSA_NAME)
1154 /* NAME + CST > NAME */
1156 else if (code2 == PLUS_EXPR)
1157 /* NAME + CST1 > NAME + CST2, if CST1 > CST2 */
1158 return compare_values_warnv (c1, c2, strict_overflow_p);
1159 else if (code2 == MINUS_EXPR)
1160 /* NAME + CST1 > NAME - CST2 */
1163 else if (code1 == MINUS_EXPR)
1165 if (code2 == SSA_NAME)
1166 /* NAME - CST < NAME */
1168 else if (code2 == PLUS_EXPR)
1169 /* NAME - CST1 < NAME + CST2 */
1171 else if (code2 == MINUS_EXPR)
1172 /* NAME - CST1 > NAME - CST2, if CST1 < CST2. Notice that
1173 C1 and C2 are swapped in the call to compare_values. */
1174 return compare_values_warnv (c2, c1, strict_overflow_p);
1180 /* We cannot compare non-constants. */
1181 if (!is_gimple_min_invariant (val1) || !is_gimple_min_invariant (val2))
1184 if (!POINTER_TYPE_P (TREE_TYPE (val1)))
1186 /* We cannot compare overflowed values, except for overflow
1188 if (TREE_OVERFLOW (val1) || TREE_OVERFLOW (val2))
1190 if (strict_overflow_p != NULL)
1191 *strict_overflow_p = true;
1192 if (is_negative_overflow_infinity (val1))
1193 return is_negative_overflow_infinity (val2) ? 0 : -1;
1194 else if (is_negative_overflow_infinity (val2))
1196 else if (is_positive_overflow_infinity (val1))
1197 return is_positive_overflow_infinity (val2) ? 0 : 1;
1198 else if (is_positive_overflow_infinity (val2))
1203 return tree_int_cst_compare (val1, val2);
1209 /* First see if VAL1 and VAL2 are not the same. */
1210 if (val1 == val2 || operand_equal_p (val1, val2, 0))
1213 /* If VAL1 is a lower address than VAL2, return -1. */
1214 if (operand_less_p (val1, val2) == 1)
1217 /* If VAL1 is a higher address than VAL2, return +1. */
1218 if (operand_less_p (val2, val1) == 1)
1221 /* If VAL1 is different than VAL2, return +2.
1222 For integer constants we either have already returned -1 or 1
1223 or they are equivalent. We still might succeed in proving
1224 something about non-trivial operands. */
1225 if (TREE_CODE (val1) != INTEGER_CST
1226 || TREE_CODE (val2) != INTEGER_CST)
1228 t = fold_binary_to_constant (NE_EXPR, boolean_type_node, val1, val2);
1229 if (t && integer_onep (t))
1237 /* Compare values like compare_values_warnv, but treat comparisons of
1238 nonconstants which rely on undefined overflow as incomparable. */
1241 compare_values (tree val1, tree val2)
1247 ret = compare_values_warnv (val1, val2, &sop);
1249 && (!is_gimple_min_invariant (val1) || !is_gimple_min_invariant (val2)))
1255 /* Return 1 if VAL is inside value range VR (VR->MIN <= VAL <= VR->MAX),
1256 0 if VAL is not inside VR,
1257 -2 if we cannot tell either way.
1259 FIXME, the current semantics of this functions are a bit quirky
1260 when taken in the context of VRP. In here we do not care
1261 about VR's type. If VR is the anti-range ~[3, 5] the call
1262 value_inside_range (4, VR) will return 1.
1264 This is counter-intuitive in a strict sense, but the callers
1265 currently expect this. They are calling the function
1266 merely to determine whether VR->MIN <= VAL <= VR->MAX. The
1267 callers are applying the VR_RANGE/VR_ANTI_RANGE semantics
1270 This also applies to value_ranges_intersect_p and
1271 range_includes_zero_p. The semantics of VR_RANGE and
1272 VR_ANTI_RANGE should be encoded here, but that also means
1273 adapting the users of these functions to the new semantics.
1275 Benchmark compile/20001226-1.c compilation time after changing this
1279 value_inside_range (tree val, value_range_t * vr)
1283 cmp1 = operand_less_p (val, vr->min);
1289 cmp2 = operand_less_p (vr->max, val);
1297 /* Return true if value ranges VR0 and VR1 have a non-empty
1300 Benchmark compile/20001226-1.c compilation time after changing this
1305 value_ranges_intersect_p (value_range_t *vr0, value_range_t *vr1)
1307 /* The value ranges do not intersect if the maximum of the first range is
1308 less than the minimum of the second range or vice versa.
1309 When those relations are unknown, we can't do any better. */
1310 if (operand_less_p (vr0->max, vr1->min) != 0)
1312 if (operand_less_p (vr1->max, vr0->min) != 0)
1318 /* Return true if VR includes the value zero, false otherwise. FIXME,
1319 currently this will return false for an anti-range like ~[-4, 3].
1320 This will be wrong when the semantics of value_inside_range are
1321 modified (currently the users of this function expect these
1325 range_includes_zero_p (value_range_t *vr)
1329 gcc_assert (vr->type != VR_UNDEFINED
1330 && vr->type != VR_VARYING
1331 && !symbolic_range_p (vr));
1333 zero = build_int_cst (TREE_TYPE (vr->min), 0);
1334 return (value_inside_range (zero, vr) == 1);
1337 /* Return true if T, an SSA_NAME, is known to be nonnegative. Return
1338 false otherwise or if no value range information is available. */
1341 ssa_name_nonnegative_p (const_tree t)
1343 value_range_t *vr = get_value_range (t);
1348 /* Testing for VR_ANTI_RANGE is not useful here as any anti-range
1349 which would return a useful value should be encoded as a VR_RANGE. */
1350 if (vr->type == VR_RANGE)
1352 int result = compare_values (vr->min, integer_zero_node);
1354 return (result == 0 || result == 1);
1359 /* If OP has a value range with a single constant value return that,
1360 otherwise return NULL_TREE. This returns OP itself if OP is a
1364 op_with_constant_singleton_value_range (tree op)
1368 if (is_gimple_min_invariant (op))
1371 if (TREE_CODE (op) != SSA_NAME)
1374 vr = get_value_range (op);
1375 if (vr->type == VR_RANGE
1376 && operand_equal_p (vr->min, vr->max, 0)
1377 && is_gimple_min_invariant (vr->min))
1384 /* Extract value range information from an ASSERT_EXPR EXPR and store
1388 extract_range_from_assert (value_range_t *vr_p, tree expr)
1390 tree var, cond, limit, min, max, type;
1391 value_range_t *var_vr, *limit_vr;
1392 enum tree_code cond_code;
1394 var = ASSERT_EXPR_VAR (expr);
1395 cond = ASSERT_EXPR_COND (expr);
1397 gcc_assert (COMPARISON_CLASS_P (cond));
1399 /* Find VAR in the ASSERT_EXPR conditional. */
1400 if (var == TREE_OPERAND (cond, 0)
1401 || TREE_CODE (TREE_OPERAND (cond, 0)) == PLUS_EXPR
1402 || TREE_CODE (TREE_OPERAND (cond, 0)) == NOP_EXPR)
1404 /* If the predicate is of the form VAR COMP LIMIT, then we just
1405 take LIMIT from the RHS and use the same comparison code. */
1406 cond_code = TREE_CODE (cond);
1407 limit = TREE_OPERAND (cond, 1);
1408 cond = TREE_OPERAND (cond, 0);
1412 /* If the predicate is of the form LIMIT COMP VAR, then we need
1413 to flip around the comparison code to create the proper range
1415 cond_code = swap_tree_comparison (TREE_CODE (cond));
1416 limit = TREE_OPERAND (cond, 0);
1417 cond = TREE_OPERAND (cond, 1);
1420 limit = avoid_overflow_infinity (limit);
1422 type = TREE_TYPE (limit);
1423 gcc_assert (limit != var);
1425 /* For pointer arithmetic, we only keep track of pointer equality
1427 if (POINTER_TYPE_P (type) && cond_code != NE_EXPR && cond_code != EQ_EXPR)
1429 set_value_range_to_varying (vr_p);
1433 /* If LIMIT is another SSA name and LIMIT has a range of its own,
1434 try to use LIMIT's range to avoid creating symbolic ranges
1436 limit_vr = (TREE_CODE (limit) == SSA_NAME) ? get_value_range (limit) : NULL;
1438 /* LIMIT's range is only interesting if it has any useful information. */
1440 && (limit_vr->type == VR_UNDEFINED
1441 || limit_vr->type == VR_VARYING
1442 || symbolic_range_p (limit_vr)))
1445 /* Initially, the new range has the same set of equivalences of
1446 VAR's range. This will be revised before returning the final
1447 value. Since assertions may be chained via mutually exclusive
1448 predicates, we will need to trim the set of equivalences before
1450 gcc_assert (vr_p->equiv == NULL);
1451 add_equivalence (&vr_p->equiv, var);
1453 /* Extract a new range based on the asserted comparison for VAR and
1454 LIMIT's value range. Notice that if LIMIT has an anti-range, we
1455 will only use it for equality comparisons (EQ_EXPR). For any
1456 other kind of assertion, we cannot derive a range from LIMIT's
1457 anti-range that can be used to describe the new range. For
1458 instance, ASSERT_EXPR <x_2, x_2 <= b_4>. If b_4 is ~[2, 10],
1459 then b_4 takes on the ranges [-INF, 1] and [11, +INF]. There is
1460 no single range for x_2 that could describe LE_EXPR, so we might
1461 as well build the range [b_4, +INF] for it.
1462 One special case we handle is extracting a range from a
1463 range test encoded as (unsigned)var + CST <= limit. */
1464 if (TREE_CODE (cond) == NOP_EXPR
1465 || TREE_CODE (cond) == PLUS_EXPR)
1467 if (TREE_CODE (cond) == PLUS_EXPR)
1469 min = fold_build1 (NEGATE_EXPR, TREE_TYPE (TREE_OPERAND (cond, 1)),
1470 TREE_OPERAND (cond, 1));
1471 max = int_const_binop (PLUS_EXPR, limit, min, 0);
1472 cond = TREE_OPERAND (cond, 0);
1476 min = build_int_cst (TREE_TYPE (var), 0);
1480 /* Make sure to not set TREE_OVERFLOW on the final type
1481 conversion. We are willingly interpreting large positive
1482 unsigned values as negative singed values here. */
1483 min = force_fit_type_double (TREE_TYPE (var), TREE_INT_CST_LOW (min),
1484 TREE_INT_CST_HIGH (min), 0, false);
1485 max = force_fit_type_double (TREE_TYPE (var), TREE_INT_CST_LOW (max),
1486 TREE_INT_CST_HIGH (max), 0, false);
1488 /* We can transform a max, min range to an anti-range or
1489 vice-versa. Use set_and_canonicalize_value_range which does
1491 if (cond_code == LE_EXPR)
1492 set_and_canonicalize_value_range (vr_p, VR_RANGE,
1493 min, max, vr_p->equiv);
1494 else if (cond_code == GT_EXPR)
1495 set_and_canonicalize_value_range (vr_p, VR_ANTI_RANGE,
1496 min, max, vr_p->equiv);
1500 else if (cond_code == EQ_EXPR)
1502 enum value_range_type range_type;
1506 range_type = limit_vr->type;
1507 min = limit_vr->min;
1508 max = limit_vr->max;
1512 range_type = VR_RANGE;
1517 set_value_range (vr_p, range_type, min, max, vr_p->equiv);
1519 /* When asserting the equality VAR == LIMIT and LIMIT is another
1520 SSA name, the new range will also inherit the equivalence set
1522 if (TREE_CODE (limit) == SSA_NAME)
1523 add_equivalence (&vr_p->equiv, limit);
1525 else if (cond_code == NE_EXPR)
1527 /* As described above, when LIMIT's range is an anti-range and
1528 this assertion is an inequality (NE_EXPR), then we cannot
1529 derive anything from the anti-range. For instance, if
1530 LIMIT's range was ~[0, 0], the assertion 'VAR != LIMIT' does
1531 not imply that VAR's range is [0, 0]. So, in the case of
1532 anti-ranges, we just assert the inequality using LIMIT and
1535 If LIMIT_VR is a range, we can only use it to build a new
1536 anti-range if LIMIT_VR is a single-valued range. For
1537 instance, if LIMIT_VR is [0, 1], the predicate
1538 VAR != [0, 1] does not mean that VAR's range is ~[0, 1].
1539 Rather, it means that for value 0 VAR should be ~[0, 0]
1540 and for value 1, VAR should be ~[1, 1]. We cannot
1541 represent these ranges.
1543 The only situation in which we can build a valid
1544 anti-range is when LIMIT_VR is a single-valued range
1545 (i.e., LIMIT_VR->MIN == LIMIT_VR->MAX). In that case,
1546 build the anti-range ~[LIMIT_VR->MIN, LIMIT_VR->MAX]. */
1548 && limit_vr->type == VR_RANGE
1549 && compare_values (limit_vr->min, limit_vr->max) == 0)
1551 min = limit_vr->min;
1552 max = limit_vr->max;
1556 /* In any other case, we cannot use LIMIT's range to build a
1557 valid anti-range. */
1561 /* If MIN and MAX cover the whole range for their type, then
1562 just use the original LIMIT. */
1563 if (INTEGRAL_TYPE_P (type)
1564 && vrp_val_is_min (min)
1565 && vrp_val_is_max (max))
1568 set_value_range (vr_p, VR_ANTI_RANGE, min, max, vr_p->equiv);
1570 else if (cond_code == LE_EXPR || cond_code == LT_EXPR)
1572 min = TYPE_MIN_VALUE (type);
1574 if (limit_vr == NULL || limit_vr->type == VR_ANTI_RANGE)
1578 /* If LIMIT_VR is of the form [N1, N2], we need to build the
1579 range [MIN, N2] for LE_EXPR and [MIN, N2 - 1] for
1581 max = limit_vr->max;
1584 /* If the maximum value forces us to be out of bounds, simply punt.
1585 It would be pointless to try and do anything more since this
1586 all should be optimized away above us. */
1587 if ((cond_code == LT_EXPR
1588 && compare_values (max, min) == 0)
1589 || (CONSTANT_CLASS_P (max) && TREE_OVERFLOW (max)))
1590 set_value_range_to_varying (vr_p);
1593 /* For LT_EXPR, we create the range [MIN, MAX - 1]. */
1594 if (cond_code == LT_EXPR)
1596 tree one = build_int_cst (type, 1);
1597 max = fold_build2 (MINUS_EXPR, type, max, one);
1599 TREE_NO_WARNING (max) = 1;
1602 set_value_range (vr_p, VR_RANGE, min, max, vr_p->equiv);
1605 else if (cond_code == GE_EXPR || cond_code == GT_EXPR)
1607 max = TYPE_MAX_VALUE (type);
1609 if (limit_vr == NULL || limit_vr->type == VR_ANTI_RANGE)
1613 /* If LIMIT_VR is of the form [N1, N2], we need to build the
1614 range [N1, MAX] for GE_EXPR and [N1 + 1, MAX] for
1616 min = limit_vr->min;
1619 /* If the minimum value forces us to be out of bounds, simply punt.
1620 It would be pointless to try and do anything more since this
1621 all should be optimized away above us. */
1622 if ((cond_code == GT_EXPR
1623 && compare_values (min, max) == 0)
1624 || (CONSTANT_CLASS_P (min) && TREE_OVERFLOW (min)))
1625 set_value_range_to_varying (vr_p);
1628 /* For GT_EXPR, we create the range [MIN + 1, MAX]. */
1629 if (cond_code == GT_EXPR)
1631 tree one = build_int_cst (type, 1);
1632 min = fold_build2 (PLUS_EXPR, type, min, one);
1634 TREE_NO_WARNING (min) = 1;
1637 set_value_range (vr_p, VR_RANGE, min, max, vr_p->equiv);
1643 /* If VAR already had a known range, it may happen that the new
1644 range we have computed and VAR's range are not compatible. For
1648 p_6 = ASSERT_EXPR <p_5, p_5 == NULL>;
1650 p_8 = ASSERT_EXPR <p_6, p_6 != NULL>;
1652 While the above comes from a faulty program, it will cause an ICE
1653 later because p_8 and p_6 will have incompatible ranges and at
1654 the same time will be considered equivalent. A similar situation
1658 i_6 = ASSERT_EXPR <i_5, i_5 > 10>;
1660 i_7 = ASSERT_EXPR <i_6, i_6 < 5>;
1662 Again i_6 and i_7 will have incompatible ranges. It would be
1663 pointless to try and do anything with i_7's range because
1664 anything dominated by 'if (i_5 < 5)' will be optimized away.
1665 Note, due to the wa in which simulation proceeds, the statement
1666 i_7 = ASSERT_EXPR <...> we would never be visited because the
1667 conditional 'if (i_5 < 5)' always evaluates to false. However,
1668 this extra check does not hurt and may protect against future
1669 changes to VRP that may get into a situation similar to the
1670 NULL pointer dereference example.
1672 Note that these compatibility tests are only needed when dealing
1673 with ranges or a mix of range and anti-range. If VAR_VR and VR_P
1674 are both anti-ranges, they will always be compatible, because two
1675 anti-ranges will always have a non-empty intersection. */
1677 var_vr = get_value_range (var);
1679 /* We may need to make adjustments when VR_P and VAR_VR are numeric
1680 ranges or anti-ranges. */
1681 if (vr_p->type == VR_VARYING
1682 || vr_p->type == VR_UNDEFINED
1683 || var_vr->type == VR_VARYING
1684 || var_vr->type == VR_UNDEFINED
1685 || symbolic_range_p (vr_p)
1686 || symbolic_range_p (var_vr))
1689 if (var_vr->type == VR_RANGE && vr_p->type == VR_RANGE)
1691 /* If the two ranges have a non-empty intersection, we can
1692 refine the resulting range. Since the assert expression
1693 creates an equivalency and at the same time it asserts a
1694 predicate, we can take the intersection of the two ranges to
1695 get better precision. */
1696 if (value_ranges_intersect_p (var_vr, vr_p))
1698 /* Use the larger of the two minimums. */
1699 if (compare_values (vr_p->min, var_vr->min) == -1)
1704 /* Use the smaller of the two maximums. */
1705 if (compare_values (vr_p->max, var_vr->max) == 1)
1710 set_value_range (vr_p, vr_p->type, min, max, vr_p->equiv);
1714 /* The two ranges do not intersect, set the new range to
1715 VARYING, because we will not be able to do anything
1716 meaningful with it. */
1717 set_value_range_to_varying (vr_p);
1720 else if ((var_vr->type == VR_RANGE && vr_p->type == VR_ANTI_RANGE)
1721 || (var_vr->type == VR_ANTI_RANGE && vr_p->type == VR_RANGE))
1723 /* A range and an anti-range will cancel each other only if
1724 their ends are the same. For instance, in the example above,
1725 p_8's range ~[0, 0] and p_6's range [0, 0] are incompatible,
1726 so VR_P should be set to VR_VARYING. */
1727 if (compare_values (var_vr->min, vr_p->min) == 0
1728 && compare_values (var_vr->max, vr_p->max) == 0)
1729 set_value_range_to_varying (vr_p);
1732 tree min, max, anti_min, anti_max, real_min, real_max;
1735 /* We want to compute the logical AND of the two ranges;
1736 there are three cases to consider.
1739 1. The VR_ANTI_RANGE range is completely within the
1740 VR_RANGE and the endpoints of the ranges are
1741 different. In that case the resulting range
1742 should be whichever range is more precise.
1743 Typically that will be the VR_RANGE.
1745 2. The VR_ANTI_RANGE is completely disjoint from
1746 the VR_RANGE. In this case the resulting range
1747 should be the VR_RANGE.
1749 3. There is some overlap between the VR_ANTI_RANGE
1752 3a. If the high limit of the VR_ANTI_RANGE resides
1753 within the VR_RANGE, then the result is a new
1754 VR_RANGE starting at the high limit of the
1755 VR_ANTI_RANGE + 1 and extending to the
1756 high limit of the original VR_RANGE.
1758 3b. If the low limit of the VR_ANTI_RANGE resides
1759 within the VR_RANGE, then the result is a new
1760 VR_RANGE starting at the low limit of the original
1761 VR_RANGE and extending to the low limit of the
1762 VR_ANTI_RANGE - 1. */
1763 if (vr_p->type == VR_ANTI_RANGE)
1765 anti_min = vr_p->min;
1766 anti_max = vr_p->max;
1767 real_min = var_vr->min;
1768 real_max = var_vr->max;
1772 anti_min = var_vr->min;
1773 anti_max = var_vr->max;
1774 real_min = vr_p->min;
1775 real_max = vr_p->max;
1779 /* Case 1, VR_ANTI_RANGE completely within VR_RANGE,
1780 not including any endpoints. */
1781 if (compare_values (anti_max, real_max) == -1
1782 && compare_values (anti_min, real_min) == 1)
1784 /* If the range is covering the whole valid range of
1785 the type keep the anti-range. */
1786 if (!vrp_val_is_min (real_min)
1787 || !vrp_val_is_max (real_max))
1788 set_value_range (vr_p, VR_RANGE, real_min,
1789 real_max, vr_p->equiv);
1791 /* Case 2, VR_ANTI_RANGE completely disjoint from
1793 else if (compare_values (anti_min, real_max) == 1
1794 || compare_values (anti_max, real_min) == -1)
1796 set_value_range (vr_p, VR_RANGE, real_min,
1797 real_max, vr_p->equiv);
1799 /* Case 3a, the anti-range extends into the low
1800 part of the real range. Thus creating a new
1801 low for the real range. */
1802 else if (((cmp = compare_values (anti_max, real_min)) == 1
1804 && compare_values (anti_max, real_max) == -1)
1806 gcc_assert (!is_positive_overflow_infinity (anti_max));
1807 if (needs_overflow_infinity (TREE_TYPE (anti_max))
1808 && vrp_val_is_max (anti_max))
1810 if (!supports_overflow_infinity (TREE_TYPE (var_vr->min)))
1812 set_value_range_to_varying (vr_p);
1815 min = positive_overflow_infinity (TREE_TYPE (var_vr->min));
1817 else if (!POINTER_TYPE_P (TREE_TYPE (var_vr->min)))
1818 min = fold_build2 (PLUS_EXPR, TREE_TYPE (var_vr->min),
1820 build_int_cst (TREE_TYPE (var_vr->min), 1));
1822 min = fold_build2 (POINTER_PLUS_EXPR, TREE_TYPE (var_vr->min),
1823 anti_max, size_int (1));
1825 set_value_range (vr_p, VR_RANGE, min, max, vr_p->equiv);
1827 /* Case 3b, the anti-range extends into the high
1828 part of the real range. Thus creating a new
1829 higher for the real range. */
1830 else if (compare_values (anti_min, real_min) == 1
1831 && ((cmp = compare_values (anti_min, real_max)) == -1
1834 gcc_assert (!is_negative_overflow_infinity (anti_min));
1835 if (needs_overflow_infinity (TREE_TYPE (anti_min))
1836 && vrp_val_is_min (anti_min))
1838 if (!supports_overflow_infinity (TREE_TYPE (var_vr->min)))
1840 set_value_range_to_varying (vr_p);
1843 max = negative_overflow_infinity (TREE_TYPE (var_vr->min));
1845 else if (!POINTER_TYPE_P (TREE_TYPE (var_vr->min)))
1846 max = fold_build2 (MINUS_EXPR, TREE_TYPE (var_vr->min),
1848 build_int_cst (TREE_TYPE (var_vr->min), 1));
1850 max = fold_build2 (POINTER_PLUS_EXPR, TREE_TYPE (var_vr->min),
1854 set_value_range (vr_p, VR_RANGE, min, max, vr_p->equiv);
1861 /* Extract range information from SSA name VAR and store it in VR. If
1862 VAR has an interesting range, use it. Otherwise, create the
1863 range [VAR, VAR] and return it. This is useful in situations where
1864 we may have conditionals testing values of VARYING names. For
1871 Even if y_5 is deemed VARYING, we can determine that x_3 > y_5 is
1875 extract_range_from_ssa_name (value_range_t *vr, tree var)
1877 value_range_t *var_vr = get_value_range (var);
1879 if (var_vr->type != VR_UNDEFINED && var_vr->type != VR_VARYING)
1880 copy_value_range (vr, var_vr);
1882 set_value_range (vr, VR_RANGE, var, var, NULL);
1884 add_equivalence (&vr->equiv, var);
1888 /* Wrapper around int_const_binop. If the operation overflows and we
1889 are not using wrapping arithmetic, then adjust the result to be
1890 -INF or +INF depending on CODE, VAL1 and VAL2. This can return
1891 NULL_TREE if we need to use an overflow infinity representation but
1892 the type does not support it. */
1895 vrp_int_const_binop (enum tree_code code, tree val1, tree val2)
1899 res = int_const_binop (code, val1, val2, 0);
1901 /* If we are not using wrapping arithmetic, operate symbolically
1902 on -INF and +INF. */
1903 if (TYPE_OVERFLOW_WRAPS (TREE_TYPE (val1)))
1905 int checkz = compare_values (res, val1);
1906 bool overflow = false;
1908 /* Ensure that res = val1 [+*] val2 >= val1
1909 or that res = val1 - val2 <= val1. */
1910 if ((code == PLUS_EXPR
1911 && !(checkz == 1 || checkz == 0))
1912 || (code == MINUS_EXPR
1913 && !(checkz == 0 || checkz == -1)))
1917 /* Checking for multiplication overflow is done by dividing the
1918 output of the multiplication by the first input of the
1919 multiplication. If the result of that division operation is
1920 not equal to the second input of the multiplication, then the
1921 multiplication overflowed. */
1922 else if (code == MULT_EXPR && !integer_zerop (val1))
1924 tree tmp = int_const_binop (TRUNC_DIV_EXPR,
1927 int check = compare_values (tmp, val2);
1935 res = copy_node (res);
1936 TREE_OVERFLOW (res) = 1;
1940 else if ((TREE_OVERFLOW (res)
1941 && !TREE_OVERFLOW (val1)
1942 && !TREE_OVERFLOW (val2))
1943 || is_overflow_infinity (val1)
1944 || is_overflow_infinity (val2))
1946 /* If the operation overflowed but neither VAL1 nor VAL2 are
1947 overflown, return -INF or +INF depending on the operation
1948 and the combination of signs of the operands. */
1949 int sgn1 = tree_int_cst_sgn (val1);
1950 int sgn2 = tree_int_cst_sgn (val2);
1952 if (needs_overflow_infinity (TREE_TYPE (res))
1953 && !supports_overflow_infinity (TREE_TYPE (res)))
1956 /* We have to punt on adding infinities of different signs,
1957 since we can't tell what the sign of the result should be.
1958 Likewise for subtracting infinities of the same sign. */
1959 if (((code == PLUS_EXPR && sgn1 != sgn2)
1960 || (code == MINUS_EXPR && sgn1 == sgn2))
1961 && is_overflow_infinity (val1)
1962 && is_overflow_infinity (val2))
1965 /* Don't try to handle division or shifting of infinities. */
1966 if ((code == TRUNC_DIV_EXPR
1967 || code == FLOOR_DIV_EXPR
1968 || code == CEIL_DIV_EXPR
1969 || code == EXACT_DIV_EXPR
1970 || code == ROUND_DIV_EXPR
1971 || code == RSHIFT_EXPR)
1972 && (is_overflow_infinity (val1)
1973 || is_overflow_infinity (val2)))
1976 /* Notice that we only need to handle the restricted set of
1977 operations handled by extract_range_from_binary_expr.
1978 Among them, only multiplication, addition and subtraction
1979 can yield overflow without overflown operands because we
1980 are working with integral types only... except in the
1981 case VAL1 = -INF and VAL2 = -1 which overflows to +INF
1982 for division too. */
1984 /* For multiplication, the sign of the overflow is given
1985 by the comparison of the signs of the operands. */
1986 if ((code == MULT_EXPR && sgn1 == sgn2)
1987 /* For addition, the operands must be of the same sign
1988 to yield an overflow. Its sign is therefore that
1989 of one of the operands, for example the first. For
1990 infinite operands X + -INF is negative, not positive. */
1991 || (code == PLUS_EXPR
1993 ? !is_negative_overflow_infinity (val2)
1994 : is_positive_overflow_infinity (val2)))
1995 /* For subtraction, non-infinite operands must be of
1996 different signs to yield an overflow. Its sign is
1997 therefore that of the first operand or the opposite of
1998 that of the second operand. A first operand of 0 counts
1999 as positive here, for the corner case 0 - (-INF), which
2000 overflows, but must yield +INF. For infinite operands 0
2001 - INF is negative, not positive. */
2002 || (code == MINUS_EXPR
2004 ? !is_positive_overflow_infinity (val2)
2005 : is_negative_overflow_infinity (val2)))
2006 /* We only get in here with positive shift count, so the
2007 overflow direction is the same as the sign of val1.
2008 Actually rshift does not overflow at all, but we only
2009 handle the case of shifting overflowed -INF and +INF. */
2010 || (code == RSHIFT_EXPR
2012 /* For division, the only case is -INF / -1 = +INF. */
2013 || code == TRUNC_DIV_EXPR
2014 || code == FLOOR_DIV_EXPR
2015 || code == CEIL_DIV_EXPR
2016 || code == EXACT_DIV_EXPR
2017 || code == ROUND_DIV_EXPR)
2018 return (needs_overflow_infinity (TREE_TYPE (res))
2019 ? positive_overflow_infinity (TREE_TYPE (res))
2020 : TYPE_MAX_VALUE (TREE_TYPE (res)));
2022 return (needs_overflow_infinity (TREE_TYPE (res))
2023 ? negative_overflow_infinity (TREE_TYPE (res))
2024 : TYPE_MIN_VALUE (TREE_TYPE (res)));
2031 /* Extract range information from a binary expression EXPR based on
2032 the ranges of each of its operands and the expression code. */
2035 extract_range_from_binary_expr (value_range_t *vr,
2036 enum tree_code code,
2037 tree expr_type, tree op0, tree op1)
2039 enum value_range_type type;
2042 value_range_t vr0 = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
2043 value_range_t vr1 = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
2045 /* Not all binary expressions can be applied to ranges in a
2046 meaningful way. Handle only arithmetic operations. */
2047 if (code != PLUS_EXPR
2048 && code != MINUS_EXPR
2049 && code != POINTER_PLUS_EXPR
2050 && code != MULT_EXPR
2051 && code != TRUNC_DIV_EXPR
2052 && code != FLOOR_DIV_EXPR
2053 && code != CEIL_DIV_EXPR
2054 && code != EXACT_DIV_EXPR
2055 && code != ROUND_DIV_EXPR
2056 && code != RSHIFT_EXPR
2059 && code != BIT_AND_EXPR
2060 && code != BIT_IOR_EXPR
2061 && code != TRUTH_AND_EXPR
2062 && code != TRUTH_OR_EXPR)
2064 /* We can still do constant propagation here. */
2065 tree const_op0 = op_with_constant_singleton_value_range (op0);
2066 tree const_op1 = op_with_constant_singleton_value_range (op1);
2067 if (const_op0 || const_op1)
2069 tree tem = fold_binary (code, expr_type,
2070 const_op0 ? const_op0 : op0,
2071 const_op1 ? const_op1 : op1);
2073 && is_gimple_min_invariant (tem)
2074 && !is_overflow_infinity (tem))
2076 set_value_range (vr, VR_RANGE, tem, tem, NULL);
2080 set_value_range_to_varying (vr);
2084 /* Get value ranges for each operand. For constant operands, create
2085 a new value range with the operand to simplify processing. */
2086 if (TREE_CODE (op0) == SSA_NAME)
2087 vr0 = *(get_value_range (op0));
2088 else if (is_gimple_min_invariant (op0))
2089 set_value_range_to_value (&vr0, op0, NULL);
2091 set_value_range_to_varying (&vr0);
2093 if (TREE_CODE (op1) == SSA_NAME)
2094 vr1 = *(get_value_range (op1));
2095 else if (is_gimple_min_invariant (op1))
2096 set_value_range_to_value (&vr1, op1, NULL);
2098 set_value_range_to_varying (&vr1);
2100 /* If either range is UNDEFINED, so is the result. */
2101 if (vr0.type == VR_UNDEFINED || vr1.type == VR_UNDEFINED)
2103 set_value_range_to_undefined (vr);
2107 /* The type of the resulting value range defaults to VR0.TYPE. */
2110 /* Refuse to operate on VARYING ranges, ranges of different kinds
2111 and symbolic ranges. As an exception, we allow BIT_AND_EXPR
2112 because we may be able to derive a useful range even if one of
2113 the operands is VR_VARYING or symbolic range. Similarly for
2114 divisions. TODO, we may be able to derive anti-ranges in
2116 if (code != BIT_AND_EXPR
2117 && code != TRUTH_AND_EXPR
2118 && code != TRUTH_OR_EXPR
2119 && code != TRUNC_DIV_EXPR
2120 && code != FLOOR_DIV_EXPR
2121 && code != CEIL_DIV_EXPR
2122 && code != EXACT_DIV_EXPR
2123 && code != ROUND_DIV_EXPR
2124 && (vr0.type == VR_VARYING
2125 || vr1.type == VR_VARYING
2126 || vr0.type != vr1.type
2127 || symbolic_range_p (&vr0)
2128 || symbolic_range_p (&vr1)))
2130 set_value_range_to_varying (vr);
2134 /* Now evaluate the expression to determine the new range. */
2135 if (POINTER_TYPE_P (expr_type)
2136 || POINTER_TYPE_P (TREE_TYPE (op0))
2137 || POINTER_TYPE_P (TREE_TYPE (op1)))
2139 if (code == MIN_EXPR || code == MAX_EXPR)
2141 /* For MIN/MAX expressions with pointers, we only care about
2142 nullness, if both are non null, then the result is nonnull.
2143 If both are null, then the result is null. Otherwise they
2145 if (range_is_nonnull (&vr0) && range_is_nonnull (&vr1))
2146 set_value_range_to_nonnull (vr, expr_type);
2147 else if (range_is_null (&vr0) && range_is_null (&vr1))
2148 set_value_range_to_null (vr, expr_type);
2150 set_value_range_to_varying (vr);
2154 gcc_assert (code == POINTER_PLUS_EXPR);
2155 /* For pointer types, we are really only interested in asserting
2156 whether the expression evaluates to non-NULL. */
2157 if (range_is_nonnull (&vr0) || range_is_nonnull (&vr1))
2158 set_value_range_to_nonnull (vr, expr_type);
2159 else if (range_is_null (&vr0) && range_is_null (&vr1))
2160 set_value_range_to_null (vr, expr_type);
2162 set_value_range_to_varying (vr);
2167 /* For integer ranges, apply the operation to each end of the
2168 range and see what we end up with. */
2169 if (code == TRUTH_AND_EXPR
2170 || code == TRUTH_OR_EXPR)
2172 /* If one of the operands is zero, we know that the whole
2173 expression evaluates zero. */
2174 if (code == TRUTH_AND_EXPR
2175 && ((vr0.type == VR_RANGE
2176 && integer_zerop (vr0.min)
2177 && integer_zerop (vr0.max))
2178 || (vr1.type == VR_RANGE
2179 && integer_zerop (vr1.min)
2180 && integer_zerop (vr1.max))))
2183 min = max = build_int_cst (expr_type, 0);
2185 /* If one of the operands is one, we know that the whole
2186 expression evaluates one. */
2187 else if (code == TRUTH_OR_EXPR
2188 && ((vr0.type == VR_RANGE
2189 && integer_onep (vr0.min)
2190 && integer_onep (vr0.max))
2191 || (vr1.type == VR_RANGE
2192 && integer_onep (vr1.min)
2193 && integer_onep (vr1.max))))
2196 min = max = build_int_cst (expr_type, 1);
2198 else if (vr0.type != VR_VARYING
2199 && vr1.type != VR_VARYING
2200 && vr0.type == vr1.type
2201 && !symbolic_range_p (&vr0)
2202 && !overflow_infinity_range_p (&vr0)
2203 && !symbolic_range_p (&vr1)
2204 && !overflow_infinity_range_p (&vr1))
2206 /* Boolean expressions cannot be folded with int_const_binop. */
2207 min = fold_binary (code, expr_type, vr0.min, vr1.min);
2208 max = fold_binary (code, expr_type, vr0.max, vr1.max);
2212 /* The result of a TRUTH_*_EXPR is always true or false. */
2213 set_value_range_to_truthvalue (vr, expr_type);
2217 else if (code == PLUS_EXPR
2219 || code == MAX_EXPR)
2221 /* If we have a PLUS_EXPR with two VR_ANTI_RANGEs, drop to
2222 VR_VARYING. It would take more effort to compute a precise
2223 range for such a case. For example, if we have op0 == 1 and
2224 op1 == -1 with their ranges both being ~[0,0], we would have
2225 op0 + op1 == 0, so we cannot claim that the sum is in ~[0,0].
2226 Note that we are guaranteed to have vr0.type == vr1.type at
2228 if (code == PLUS_EXPR && vr0.type == VR_ANTI_RANGE)
2230 set_value_range_to_varying (vr);
2234 /* For operations that make the resulting range directly
2235 proportional to the original ranges, apply the operation to
2236 the same end of each range. */
2237 min = vrp_int_const_binop (code, vr0.min, vr1.min);
2238 max = vrp_int_const_binop (code, vr0.max, vr1.max);
2240 /* If both additions overflowed the range kind is still correct.
2241 This happens regularly with subtracting something in unsigned
2243 ??? See PR30318 for all the cases we do not handle. */
2244 if (code == PLUS_EXPR
2245 && (TREE_OVERFLOW (min) && !is_overflow_infinity (min))
2246 && (TREE_OVERFLOW (max) && !is_overflow_infinity (max)))
2248 min = build_int_cst_wide (TREE_TYPE (min),
2249 TREE_INT_CST_LOW (min),
2250 TREE_INT_CST_HIGH (min));
2251 max = build_int_cst_wide (TREE_TYPE (max),
2252 TREE_INT_CST_LOW (max),
2253 TREE_INT_CST_HIGH (max));
2256 else if (code == MULT_EXPR
2257 || code == TRUNC_DIV_EXPR
2258 || code == FLOOR_DIV_EXPR
2259 || code == CEIL_DIV_EXPR
2260 || code == EXACT_DIV_EXPR
2261 || code == ROUND_DIV_EXPR
2262 || code == RSHIFT_EXPR)
2268 /* If we have an unsigned MULT_EXPR with two VR_ANTI_RANGEs,
2269 drop to VR_VARYING. It would take more effort to compute a
2270 precise range for such a case. For example, if we have
2271 op0 == 65536 and op1 == 65536 with their ranges both being
2272 ~[0,0] on a 32-bit machine, we would have op0 * op1 == 0, so
2273 we cannot claim that the product is in ~[0,0]. Note that we
2274 are guaranteed to have vr0.type == vr1.type at this
2276 if (code == MULT_EXPR
2277 && vr0.type == VR_ANTI_RANGE
2278 && !TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (op0)))
2280 set_value_range_to_varying (vr);
2284 /* If we have a RSHIFT_EXPR with any shift values outside [0..prec-1],
2285 then drop to VR_VARYING. Outside of this range we get undefined
2286 behavior from the shift operation. We cannot even trust
2287 SHIFT_COUNT_TRUNCATED at this stage, because that applies to rtl
2288 shifts, and the operation at the tree level may be widened. */
2289 if (code == RSHIFT_EXPR)
2291 if (vr1.type == VR_ANTI_RANGE
2292 || !vrp_expr_computes_nonnegative (op1, &sop)
2294 (build_int_cst (TREE_TYPE (vr1.max),
2295 TYPE_PRECISION (expr_type) - 1),
2298 set_value_range_to_varying (vr);
2303 else if ((code == TRUNC_DIV_EXPR
2304 || code == FLOOR_DIV_EXPR
2305 || code == CEIL_DIV_EXPR
2306 || code == EXACT_DIV_EXPR
2307 || code == ROUND_DIV_EXPR)
2308 && (vr0.type != VR_RANGE || symbolic_range_p (&vr0)))
2310 /* For division, if op1 has VR_RANGE but op0 does not, something
2311 can be deduced just from that range. Say [min, max] / [4, max]
2312 gives [min / 4, max / 4] range. */
2313 if (vr1.type == VR_RANGE
2314 && !symbolic_range_p (&vr1)
2315 && !range_includes_zero_p (&vr1))
2317 vr0.type = type = VR_RANGE;
2318 vr0.min = vrp_val_min (TREE_TYPE (op0));
2319 vr0.max = vrp_val_max (TREE_TYPE (op1));
2323 set_value_range_to_varying (vr);
2328 /* For divisions, if op0 is VR_RANGE, we can deduce a range
2329 even if op1 is VR_VARYING, VR_ANTI_RANGE, symbolic or can
2331 if ((code == TRUNC_DIV_EXPR
2332 || code == FLOOR_DIV_EXPR
2333 || code == CEIL_DIV_EXPR
2334 || code == EXACT_DIV_EXPR
2335 || code == ROUND_DIV_EXPR)
2336 && vr0.type == VR_RANGE
2337 && (vr1.type != VR_RANGE
2338 || symbolic_range_p (&vr1)
2339 || range_includes_zero_p (&vr1)))
2341 tree zero = build_int_cst (TREE_TYPE (vr0.min), 0);
2347 if (vrp_expr_computes_nonnegative (op1, &sop) && !sop)
2349 /* For unsigned division or when divisor is known
2350 to be non-negative, the range has to cover
2351 all numbers from 0 to max for positive max
2352 and all numbers from min to 0 for negative min. */
2353 cmp = compare_values (vr0.max, zero);
2356 else if (cmp == 0 || cmp == 1)
2360 cmp = compare_values (vr0.min, zero);
2363 else if (cmp == 0 || cmp == -1)
2370 /* Otherwise the range is -max .. max or min .. -min
2371 depending on which bound is bigger in absolute value,
2372 as the division can change the sign. */
2373 abs_extent_range (vr, vr0.min, vr0.max);
2376 if (type == VR_VARYING)
2378 set_value_range_to_varying (vr);
2383 /* Multiplications and divisions are a bit tricky to handle,
2384 depending on the mix of signs we have in the two ranges, we
2385 need to operate on different values to get the minimum and
2386 maximum values for the new range. One approach is to figure
2387 out all the variations of range combinations and do the
2390 However, this involves several calls to compare_values and it
2391 is pretty convoluted. It's simpler to do the 4 operations
2392 (MIN0 OP MIN1, MIN0 OP MAX1, MAX0 OP MIN1 and MAX0 OP MAX0 OP
2393 MAX1) and then figure the smallest and largest values to form
2397 gcc_assert ((vr0.type == VR_RANGE
2398 || (code == MULT_EXPR && vr0.type == VR_ANTI_RANGE))
2399 && vr0.type == vr1.type);
2401 /* Compute the 4 cross operations. */
2403 val[0] = vrp_int_const_binop (code, vr0.min, vr1.min);
2404 if (val[0] == NULL_TREE)
2407 if (vr1.max == vr1.min)
2411 val[1] = vrp_int_const_binop (code, vr0.min, vr1.max);
2412 if (val[1] == NULL_TREE)
2416 if (vr0.max == vr0.min)
2420 val[2] = vrp_int_const_binop (code, vr0.max, vr1.min);
2421 if (val[2] == NULL_TREE)
2425 if (vr0.min == vr0.max || vr1.min == vr1.max)
2429 val[3] = vrp_int_const_binop (code, vr0.max, vr1.max);
2430 if (val[3] == NULL_TREE)
2436 set_value_range_to_varying (vr);
2440 /* Set MIN to the minimum of VAL[i] and MAX to the maximum
2444 for (i = 1; i < 4; i++)
2446 if (!is_gimple_min_invariant (min)
2447 || (TREE_OVERFLOW (min) && !is_overflow_infinity (min))
2448 || !is_gimple_min_invariant (max)
2449 || (TREE_OVERFLOW (max) && !is_overflow_infinity (max)))
2454 if (!is_gimple_min_invariant (val[i])
2455 || (TREE_OVERFLOW (val[i])
2456 && !is_overflow_infinity (val[i])))
2458 /* If we found an overflowed value, set MIN and MAX
2459 to it so that we set the resulting range to
2465 if (compare_values (val[i], min) == -1)
2468 if (compare_values (val[i], max) == 1)
2474 else if (code == MINUS_EXPR)
2476 /* If we have a MINUS_EXPR with two VR_ANTI_RANGEs, drop to
2477 VR_VARYING. It would take more effort to compute a precise
2478 range for such a case. For example, if we have op0 == 1 and
2479 op1 == 1 with their ranges both being ~[0,0], we would have
2480 op0 - op1 == 0, so we cannot claim that the difference is in
2481 ~[0,0]. Note that we are guaranteed to have
2482 vr0.type == vr1.type at this point. */
2483 if (vr0.type == VR_ANTI_RANGE)
2485 set_value_range_to_varying (vr);
2489 /* For MINUS_EXPR, apply the operation to the opposite ends of
2491 min = vrp_int_const_binop (code, vr0.min, vr1.max);
2492 max = vrp_int_const_binop (code, vr0.max, vr1.min);
2494 else if (code == BIT_AND_EXPR)
2496 if (vr0.type == VR_RANGE
2497 && vr0.min == vr0.max
2498 && TREE_CODE (vr0.max) == INTEGER_CST
2499 && !TREE_OVERFLOW (vr0.max)
2500 && tree_int_cst_sgn (vr0.max) >= 0)
2502 min = build_int_cst (expr_type, 0);
2505 else if (vr1.type == VR_RANGE
2506 && vr1.min == vr1.max
2507 && TREE_CODE (vr1.max) == INTEGER_CST
2508 && !TREE_OVERFLOW (vr1.max)
2509 && tree_int_cst_sgn (vr1.max) >= 0)
2512 min = build_int_cst (expr_type, 0);
2517 set_value_range_to_varying (vr);
2521 else if (code == BIT_IOR_EXPR)
2523 if (vr0.type == VR_RANGE
2524 && vr1.type == VR_RANGE
2525 && TREE_CODE (vr0.min) == INTEGER_CST
2526 && TREE_CODE (vr1.min) == INTEGER_CST
2527 && TREE_CODE (vr0.max) == INTEGER_CST
2528 && TREE_CODE (vr1.max) == INTEGER_CST
2529 && tree_int_cst_sgn (vr0.min) >= 0
2530 && tree_int_cst_sgn (vr1.min) >= 0)
2532 double_int vr0_max = tree_to_double_int (vr0.max);
2533 double_int vr1_max = tree_to_double_int (vr1.max);
2536 /* Set all bits to the right of the most significant one to 1.
2537 For example, [0, 4] | [4, 4] = [4, 7]. */
2538 ior_max.low = vr0_max.low | vr1_max.low;
2539 ior_max.high = vr0_max.high | vr1_max.high;
2540 if (ior_max.high != 0)
2542 ior_max.low = ~(unsigned HOST_WIDE_INT)0u;
2543 ior_max.high |= ((HOST_WIDE_INT) 1
2544 << floor_log2 (ior_max.high)) - 1;
2546 else if (ior_max.low != 0)
2547 ior_max.low |= ((unsigned HOST_WIDE_INT) 1u
2548 << floor_log2 (ior_max.low)) - 1;
2550 /* Both of these endpoints are conservative. */
2551 min = vrp_int_const_binop (MAX_EXPR, vr0.min, vr1.min);
2552 max = double_int_to_tree (expr_type, ior_max);
2556 set_value_range_to_varying (vr);
2563 /* If either MIN or MAX overflowed, then set the resulting range to
2564 VARYING. But we do accept an overflow infinity
2566 if (min == NULL_TREE
2567 || !is_gimple_min_invariant (min)
2568 || (TREE_OVERFLOW (min) && !is_overflow_infinity (min))
2570 || !is_gimple_min_invariant (max)
2571 || (TREE_OVERFLOW (max) && !is_overflow_infinity (max)))
2573 set_value_range_to_varying (vr);
2579 2) [-INF, +-INF(OVF)]
2580 3) [+-INF(OVF), +INF]
2581 4) [+-INF(OVF), +-INF(OVF)]
2582 We learn nothing when we have INF and INF(OVF) on both sides.
2583 Note that we do accept [-INF, -INF] and [+INF, +INF] without
2585 if ((vrp_val_is_min (min) || is_overflow_infinity (min))
2586 && (vrp_val_is_max (max) || is_overflow_infinity (max)))
2588 set_value_range_to_varying (vr);
2592 cmp = compare_values (min, max);
2593 if (cmp == -2 || cmp == 1)
2595 /* If the new range has its limits swapped around (MIN > MAX),
2596 then the operation caused one of them to wrap around, mark
2597 the new range VARYING. */
2598 set_value_range_to_varying (vr);
2601 set_value_range (vr, type, min, max, NULL);
2605 /* Extract range information from a unary expression EXPR based on
2606 the range of its operand and the expression code. */
2609 extract_range_from_unary_expr (value_range_t *vr, enum tree_code code,
2610 tree type, tree op0)
2614 value_range_t vr0 = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
2616 /* Refuse to operate on certain unary expressions for which we
2617 cannot easily determine a resulting range. */
2618 if (code == FIX_TRUNC_EXPR
2619 || code == FLOAT_EXPR
2620 || code == BIT_NOT_EXPR
2621 || code == CONJ_EXPR)
2623 /* We can still do constant propagation here. */
2624 if ((op0 = op_with_constant_singleton_value_range (op0)) != NULL_TREE)
2626 tree tem = fold_unary (code, type, op0);
2628 && is_gimple_min_invariant (tem)
2629 && !is_overflow_infinity (tem))
2631 set_value_range (vr, VR_RANGE, tem, tem, NULL);
2635 set_value_range_to_varying (vr);
2639 /* Get value ranges for the operand. For constant operands, create
2640 a new value range with the operand to simplify processing. */
2641 if (TREE_CODE (op0) == SSA_NAME)
2642 vr0 = *(get_value_range (op0));
2643 else if (is_gimple_min_invariant (op0))
2644 set_value_range_to_value (&vr0, op0, NULL);
2646 set_value_range_to_varying (&vr0);
2648 /* If VR0 is UNDEFINED, so is the result. */
2649 if (vr0.type == VR_UNDEFINED)
2651 set_value_range_to_undefined (vr);
2655 /* Refuse to operate on symbolic ranges, or if neither operand is
2656 a pointer or integral type. */
2657 if ((!INTEGRAL_TYPE_P (TREE_TYPE (op0))
2658 && !POINTER_TYPE_P (TREE_TYPE (op0)))
2659 || (vr0.type != VR_VARYING
2660 && symbolic_range_p (&vr0)))
2662 set_value_range_to_varying (vr);
2666 /* If the expression involves pointers, we are only interested in
2667 determining if it evaluates to NULL [0, 0] or non-NULL (~[0, 0]). */
2668 if (POINTER_TYPE_P (type) || POINTER_TYPE_P (TREE_TYPE (op0)))
2673 if (range_is_nonnull (&vr0)
2674 || (tree_unary_nonzero_warnv_p (code, type, op0, &sop)
2676 set_value_range_to_nonnull (vr, type);
2677 else if (range_is_null (&vr0))
2678 set_value_range_to_null (vr, type);
2680 set_value_range_to_varying (vr);
2685 /* Handle unary expressions on integer ranges. */
2686 if (CONVERT_EXPR_CODE_P (code)
2687 && INTEGRAL_TYPE_P (type)
2688 && INTEGRAL_TYPE_P (TREE_TYPE (op0)))
2690 tree inner_type = TREE_TYPE (op0);
2691 tree outer_type = type;
2693 /* If VR0 is varying and we increase the type precision, assume
2694 a full range for the following transformation. */
2695 if (vr0.type == VR_VARYING
2696 && TYPE_PRECISION (inner_type) < TYPE_PRECISION (outer_type))
2698 vr0.type = VR_RANGE;
2699 vr0.min = TYPE_MIN_VALUE (inner_type);
2700 vr0.max = TYPE_MAX_VALUE (inner_type);
2703 /* If VR0 is a constant range or anti-range and the conversion is
2704 not truncating we can convert the min and max values and
2705 canonicalize the resulting range. Otherwise we can do the
2706 conversion if the size of the range is less than what the
2707 precision of the target type can represent and the range is
2708 not an anti-range. */
2709 if ((vr0.type == VR_RANGE
2710 || vr0.type == VR_ANTI_RANGE)
2711 && TREE_CODE (vr0.min) == INTEGER_CST
2712 && TREE_CODE (vr0.max) == INTEGER_CST
2713 && !is_overflow_infinity (vr0.min)
2714 && !is_overflow_infinity (vr0.max)
2715 && (TYPE_PRECISION (outer_type) >= TYPE_PRECISION (inner_type)
2716 || (vr0.type == VR_RANGE
2717 && integer_zerop (int_const_binop (RSHIFT_EXPR,
2718 int_const_binop (MINUS_EXPR, vr0.max, vr0.min, 0),
2719 size_int (TYPE_PRECISION (outer_type)), 0)))))
2721 tree new_min, new_max;
2722 new_min = force_fit_type_double (outer_type,
2723 TREE_INT_CST_LOW (vr0.min),
2724 TREE_INT_CST_HIGH (vr0.min), 0, 0);
2725 new_max = force_fit_type_double (outer_type,
2726 TREE_INT_CST_LOW (vr0.max),
2727 TREE_INT_CST_HIGH (vr0.max), 0, 0);
2728 set_and_canonicalize_value_range (vr, vr0.type,
2729 new_min, new_max, NULL);
2733 set_value_range_to_varying (vr);
2737 /* Conversion of a VR_VARYING value to a wider type can result
2738 in a usable range. So wait until after we've handled conversions
2739 before dropping the result to VR_VARYING if we had a source
2740 operand that is VR_VARYING. */
2741 if (vr0.type == VR_VARYING)
2743 set_value_range_to_varying (vr);
2747 /* Apply the operation to each end of the range and see what we end
2749 if (code == NEGATE_EXPR
2750 && !TYPE_UNSIGNED (type))
2752 /* NEGATE_EXPR flips the range around. We need to treat
2753 TYPE_MIN_VALUE specially. */
2754 if (is_positive_overflow_infinity (vr0.max))
2755 min = negative_overflow_infinity (type);
2756 else if (is_negative_overflow_infinity (vr0.max))
2757 min = positive_overflow_infinity (type);
2758 else if (!vrp_val_is_min (vr0.max))
2759 min = fold_unary_to_constant (code, type, vr0.max);
2760 else if (needs_overflow_infinity (type))
2762 if (supports_overflow_infinity (type)
2763 && !is_overflow_infinity (vr0.min)
2764 && !vrp_val_is_min (vr0.min))
2765 min = positive_overflow_infinity (type);
2768 set_value_range_to_varying (vr);
2773 min = TYPE_MIN_VALUE (type);
2775 if (is_positive_overflow_infinity (vr0.min))
2776 max = negative_overflow_infinity (type);
2777 else if (is_negative_overflow_infinity (vr0.min))
2778 max = positive_overflow_infinity (type);
2779 else if (!vrp_val_is_min (vr0.min))
2780 max = fold_unary_to_constant (code, type, vr0.min);
2781 else if (needs_overflow_infinity (type))
2783 if (supports_overflow_infinity (type))
2784 max = positive_overflow_infinity (type);
2787 set_value_range_to_varying (vr);
2792 max = TYPE_MIN_VALUE (type);
2794 else if (code == NEGATE_EXPR
2795 && TYPE_UNSIGNED (type))
2797 if (!range_includes_zero_p (&vr0))
2799 max = fold_unary_to_constant (code, type, vr0.min);
2800 min = fold_unary_to_constant (code, type, vr0.max);
2804 if (range_is_null (&vr0))
2805 set_value_range_to_null (vr, type);
2807 set_value_range_to_varying (vr);
2811 else if (code == ABS_EXPR
2812 && !TYPE_UNSIGNED (type))
2814 /* -TYPE_MIN_VALUE = TYPE_MIN_VALUE with flag_wrapv so we can't get a
2816 if (!TYPE_OVERFLOW_UNDEFINED (type)
2817 && ((vr0.type == VR_RANGE
2818 && vrp_val_is_min (vr0.min))
2819 || (vr0.type == VR_ANTI_RANGE
2820 && !vrp_val_is_min (vr0.min)
2821 && !range_includes_zero_p (&vr0))))
2823 set_value_range_to_varying (vr);
2827 /* ABS_EXPR may flip the range around, if the original range
2828 included negative values. */
2829 if (is_overflow_infinity (vr0.min))
2830 min = positive_overflow_infinity (type);
2831 else if (!vrp_val_is_min (vr0.min))
2832 min = fold_unary_to_constant (code, type, vr0.min);
2833 else if (!needs_overflow_infinity (type))
2834 min = TYPE_MAX_VALUE (type);
2835 else if (supports_overflow_infinity (type))
2836 min = positive_overflow_infinity (type);
2839 set_value_range_to_varying (vr);
2843 if (is_overflow_infinity (vr0.max))
2844 max = positive_overflow_infinity (type);
2845 else if (!vrp_val_is_min (vr0.max))
2846 max = fold_unary_to_constant (code, type, vr0.max);
2847 else if (!needs_overflow_infinity (type))
2848 max = TYPE_MAX_VALUE (type);
2849 else if (supports_overflow_infinity (type)
2850 /* We shouldn't generate [+INF, +INF] as set_value_range
2851 doesn't like this and ICEs. */
2852 && !is_positive_overflow_infinity (min))
2853 max = positive_overflow_infinity (type);
2856 set_value_range_to_varying (vr);
2860 cmp = compare_values (min, max);
2862 /* If a VR_ANTI_RANGEs contains zero, then we have
2863 ~[-INF, min(MIN, MAX)]. */
2864 if (vr0.type == VR_ANTI_RANGE)
2866 if (range_includes_zero_p (&vr0))
2868 /* Take the lower of the two values. */
2872 /* Create ~[-INF, min (abs(MIN), abs(MAX))]
2873 or ~[-INF + 1, min (abs(MIN), abs(MAX))] when
2874 flag_wrapv is set and the original anti-range doesn't include
2875 TYPE_MIN_VALUE, remember -TYPE_MIN_VALUE = TYPE_MIN_VALUE. */
2876 if (TYPE_OVERFLOW_WRAPS (type))
2878 tree type_min_value = TYPE_MIN_VALUE (type);
2880 min = (vr0.min != type_min_value
2881 ? int_const_binop (PLUS_EXPR, type_min_value,
2882 integer_one_node, 0)
2887 if (overflow_infinity_range_p (&vr0))
2888 min = negative_overflow_infinity (type);
2890 min = TYPE_MIN_VALUE (type);
2895 /* All else has failed, so create the range [0, INF], even for
2896 flag_wrapv since TYPE_MIN_VALUE is in the original
2898 vr0.type = VR_RANGE;
2899 min = build_int_cst (type, 0);
2900 if (needs_overflow_infinity (type))
2902 if (supports_overflow_infinity (type))
2903 max = positive_overflow_infinity (type);
2906 set_value_range_to_varying (vr);
2911 max = TYPE_MAX_VALUE (type);
2915 /* If the range contains zero then we know that the minimum value in the
2916 range will be zero. */
2917 else if (range_includes_zero_p (&vr0))
2921 min = build_int_cst (type, 0);
2925 /* If the range was reversed, swap MIN and MAX. */
2936 /* Otherwise, operate on each end of the range. */
2937 min = fold_unary_to_constant (code, type, vr0.min);
2938 max = fold_unary_to_constant (code, type, vr0.max);
2940 if (needs_overflow_infinity (type))
2942 gcc_assert (code != NEGATE_EXPR && code != ABS_EXPR);
2944 /* If both sides have overflowed, we don't know
2946 if ((is_overflow_infinity (vr0.min)
2947 || TREE_OVERFLOW (min))
2948 && (is_overflow_infinity (vr0.max)
2949 || TREE_OVERFLOW (max)))
2951 set_value_range_to_varying (vr);
2955 if (is_overflow_infinity (vr0.min))
2957 else if (TREE_OVERFLOW (min))
2959 if (supports_overflow_infinity (type))
2960 min = (tree_int_cst_sgn (min) >= 0
2961 ? positive_overflow_infinity (TREE_TYPE (min))
2962 : negative_overflow_infinity (TREE_TYPE (min)));
2965 set_value_range_to_varying (vr);
2970 if (is_overflow_infinity (vr0.max))
2972 else if (TREE_OVERFLOW (max))
2974 if (supports_overflow_infinity (type))
2975 max = (tree_int_cst_sgn (max) >= 0
2976 ? positive_overflow_infinity (TREE_TYPE (max))
2977 : negative_overflow_infinity (TREE_TYPE (max)));
2980 set_value_range_to_varying (vr);
2987 cmp = compare_values (min, max);
2988 if (cmp == -2 || cmp == 1)
2990 /* If the new range has its limits swapped around (MIN > MAX),
2991 then the operation caused one of them to wrap around, mark
2992 the new range VARYING. */
2993 set_value_range_to_varying (vr);
2996 set_value_range (vr, vr0.type, min, max, NULL);
3000 /* Extract range information from a conditional expression EXPR based on
3001 the ranges of each of its operands and the expression code. */
3004 extract_range_from_cond_expr (value_range_t *vr, tree expr)
3007 value_range_t vr0 = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
3008 value_range_t vr1 = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
3010 /* Get value ranges for each operand. For constant operands, create
3011 a new value range with the operand to simplify processing. */
3012 op0 = COND_EXPR_THEN (expr);
3013 if (TREE_CODE (op0) == SSA_NAME)
3014 vr0 = *(get_value_range (op0));
3015 else if (is_gimple_min_invariant (op0))
3016 set_value_range_to_value (&vr0, op0, NULL);
3018 set_value_range_to_varying (&vr0);
3020 op1 = COND_EXPR_ELSE (expr);
3021 if (TREE_CODE (op1) == SSA_NAME)
3022 vr1 = *(get_value_range (op1));
3023 else if (is_gimple_min_invariant (op1))
3024 set_value_range_to_value (&vr1, op1, NULL);
3026 set_value_range_to_varying (&vr1);
3028 /* The resulting value range is the union of the operand ranges */
3029 vrp_meet (&vr0, &vr1);
3030 copy_value_range (vr, &vr0);
3034 /* Extract range information from a comparison expression EXPR based
3035 on the range of its operand and the expression code. */
3038 extract_range_from_comparison (value_range_t *vr, enum tree_code code,
3039 tree type, tree op0, tree op1)
3044 val = vrp_evaluate_conditional_warnv_with_ops (code, op0, op1, false, &sop,
3047 /* A disadvantage of using a special infinity as an overflow
3048 representation is that we lose the ability to record overflow
3049 when we don't have an infinity. So we have to ignore a result
3050 which relies on overflow. */
3052 if (val && !is_overflow_infinity (val) && !sop)
3054 /* Since this expression was found on the RHS of an assignment,
3055 its type may be different from _Bool. Convert VAL to EXPR's
3057 val = fold_convert (type, val);
3058 if (is_gimple_min_invariant (val))
3059 set_value_range_to_value (vr, val, vr->equiv);
3061 set_value_range (vr, VR_RANGE, val, val, vr->equiv);
3064 /* The result of a comparison is always true or false. */
3065 set_value_range_to_truthvalue (vr, type);
3068 /* Try to derive a nonnegative or nonzero range out of STMT relying
3069 primarily on generic routines in fold in conjunction with range data.
3070 Store the result in *VR */
3073 extract_range_basic (value_range_t *vr, gimple stmt)
3076 tree type = gimple_expr_type (stmt);
3078 if (INTEGRAL_TYPE_P (type)
3079 && gimple_stmt_nonnegative_warnv_p (stmt, &sop))
3080 set_value_range_to_nonnegative (vr, type,
3081 sop || stmt_overflow_infinity (stmt));
3082 else if (vrp_stmt_computes_nonzero (stmt, &sop)
3084 set_value_range_to_nonnull (vr, type);
3086 set_value_range_to_varying (vr);
3090 /* Try to compute a useful range out of assignment STMT and store it
3094 extract_range_from_assignment (value_range_t *vr, gimple stmt)
3096 enum tree_code code = gimple_assign_rhs_code (stmt);
3098 if (code == ASSERT_EXPR)
3099 extract_range_from_assert (vr, gimple_assign_rhs1 (stmt));
3100 else if (code == SSA_NAME)
3101 extract_range_from_ssa_name (vr, gimple_assign_rhs1 (stmt));
3102 else if (TREE_CODE_CLASS (code) == tcc_binary
3103 || code == TRUTH_AND_EXPR
3104 || code == TRUTH_OR_EXPR
3105 || code == TRUTH_XOR_EXPR)
3106 extract_range_from_binary_expr (vr, gimple_assign_rhs_code (stmt),
3107 gimple_expr_type (stmt),
3108 gimple_assign_rhs1 (stmt),
3109 gimple_assign_rhs2 (stmt));
3110 else if (TREE_CODE_CLASS (code) == tcc_unary)
3111 extract_range_from_unary_expr (vr, gimple_assign_rhs_code (stmt),
3112 gimple_expr_type (stmt),
3113 gimple_assign_rhs1 (stmt));
3114 else if (code == COND_EXPR)
3115 extract_range_from_cond_expr (vr, gimple_assign_rhs1 (stmt));
3116 else if (TREE_CODE_CLASS (code) == tcc_comparison)
3117 extract_range_from_comparison (vr, gimple_assign_rhs_code (stmt),
3118 gimple_expr_type (stmt),
3119 gimple_assign_rhs1 (stmt),
3120 gimple_assign_rhs2 (stmt));
3121 else if (get_gimple_rhs_class (code) == GIMPLE_SINGLE_RHS
3122 && is_gimple_min_invariant (gimple_assign_rhs1 (stmt)))
3123 set_value_range_to_value (vr, gimple_assign_rhs1 (stmt), NULL);
3125 set_value_range_to_varying (vr);
3127 if (vr->type == VR_VARYING)
3128 extract_range_basic (vr, stmt);
3131 /* Given a range VR, a LOOP and a variable VAR, determine whether it
3132 would be profitable to adjust VR using scalar evolution information
3133 for VAR. If so, update VR with the new limits. */
3136 adjust_range_with_scev (value_range_t *vr, struct loop *loop,
3137 gimple stmt, tree var)
3139 tree init, step, chrec, tmin, tmax, min, max, type;
3140 enum ev_direction dir;
3142 /* TODO. Don't adjust anti-ranges. An anti-range may provide
3143 better opportunities than a regular range, but I'm not sure. */
3144 if (vr->type == VR_ANTI_RANGE)
3147 chrec = instantiate_parameters (loop, analyze_scalar_evolution (loop, var));
3149 /* Like in PR19590, scev can return a constant function. */
3150 if (is_gimple_min_invariant (chrec))
3152 set_value_range_to_value (vr, chrec, vr->equiv);
3156 if (TREE_CODE (chrec) != POLYNOMIAL_CHREC)
3159 init = initial_condition_in_loop_num (chrec, loop->num);
3160 step = evolution_part_in_loop_num (chrec, loop->num);
3162 /* If STEP is symbolic, we can't know whether INIT will be the
3163 minimum or maximum value in the range. Also, unless INIT is
3164 a simple expression, compare_values and possibly other functions
3165 in tree-vrp won't be able to handle it. */
3166 if (step == NULL_TREE
3167 || !is_gimple_min_invariant (step)
3168 || !valid_value_p (init))
3171 dir = scev_direction (chrec);
3172 if (/* Do not adjust ranges if we do not know whether the iv increases
3173 or decreases, ... */
3174 dir == EV_DIR_UNKNOWN
3175 /* ... or if it may wrap. */
3176 || scev_probably_wraps_p (init, step, stmt, get_chrec_loop (chrec),
3180 /* We use TYPE_MIN_VALUE and TYPE_MAX_VALUE here instead of
3181 negative_overflow_infinity and positive_overflow_infinity,
3182 because we have concluded that the loop probably does not
3185 type = TREE_TYPE (var);
3186 if (POINTER_TYPE_P (type) || !TYPE_MIN_VALUE (type))
3187 tmin = lower_bound_in_type (type, type);
3189 tmin = TYPE_MIN_VALUE (type);
3190 if (POINTER_TYPE_P (type) || !TYPE_MAX_VALUE (type))
3191 tmax = upper_bound_in_type (type, type);
3193 tmax = TYPE_MAX_VALUE (type);
3195 if (vr->type == VR_VARYING || vr->type == VR_UNDEFINED)
3200 /* For VARYING or UNDEFINED ranges, just about anything we get
3201 from scalar evolutions should be better. */
3203 if (dir == EV_DIR_DECREASES)
3208 /* If we would create an invalid range, then just assume we
3209 know absolutely nothing. This may be over-conservative,
3210 but it's clearly safe, and should happen only in unreachable
3211 parts of code, or for invalid programs. */
3212 if (compare_values (min, max) == 1)
3215 set_value_range (vr, VR_RANGE, min, max, vr->equiv);
3217 else if (vr->type == VR_RANGE)
3222 if (dir == EV_DIR_DECREASES)
3224 /* INIT is the maximum value. If INIT is lower than VR->MAX
3225 but no smaller than VR->MIN, set VR->MAX to INIT. */
3226 if (compare_values (init, max) == -1)
3230 /* If we just created an invalid range with the minimum
3231 greater than the maximum, we fail conservatively.
3232 This should happen only in unreachable
3233 parts of code, or for invalid programs. */
3234 if (compare_values (min, max) == 1)
3238 /* According to the loop information, the variable does not
3239 overflow. If we think it does, probably because of an
3240 overflow due to arithmetic on a different INF value,
3242 if (is_negative_overflow_infinity (min))
3247 /* If INIT is bigger than VR->MIN, set VR->MIN to INIT. */
3248 if (compare_values (init, min) == 1)
3252 /* Again, avoid creating invalid range by failing. */
3253 if (compare_values (min, max) == 1)
3257 if (is_positive_overflow_infinity (max))
3261 set_value_range (vr, VR_RANGE, min, max, vr->equiv);
3265 /* Return true if VAR may overflow at STMT. This checks any available
3266 loop information to see if we can determine that VAR does not
3270 vrp_var_may_overflow (tree var, gimple stmt)
3273 tree chrec, init, step;
3275 if (current_loops == NULL)
3278 l = loop_containing_stmt (stmt);
3282 chrec = instantiate_parameters (l, analyze_scalar_evolution (l, var));
3283 if (TREE_CODE (chrec) != POLYNOMIAL_CHREC)
3286 init = initial_condition_in_loop_num (chrec, l->num);
3287 step = evolution_part_in_loop_num (chrec, l->num);
3289 if (step == NULL_TREE
3290 || !is_gimple_min_invariant (step)
3291 || !valid_value_p (init))
3294 /* If we get here, we know something useful about VAR based on the
3295 loop information. If it wraps, it may overflow. */
3297 if (scev_probably_wraps_p (init, step, stmt, get_chrec_loop (chrec),
3301 if (dump_file && (dump_flags & TDF_DETAILS) != 0)
3303 print_generic_expr (dump_file, var, 0);
3304 fprintf (dump_file, ": loop information indicates does not overflow\n");
3311 /* Given two numeric value ranges VR0, VR1 and a comparison code COMP:
3313 - Return BOOLEAN_TRUE_NODE if VR0 COMP VR1 always returns true for
3314 all the values in the ranges.
3316 - Return BOOLEAN_FALSE_NODE if the comparison always returns false.
3318 - Return NULL_TREE if it is not always possible to determine the
3319 value of the comparison.
3321 Also set *STRICT_OVERFLOW_P to indicate whether a range with an
3322 overflow infinity was used in the test. */
3326 compare_ranges (enum tree_code comp, value_range_t *vr0, value_range_t *vr1,
3327 bool *strict_overflow_p)
3329 /* VARYING or UNDEFINED ranges cannot be compared. */
3330 if (vr0->type == VR_VARYING
3331 || vr0->type == VR_UNDEFINED
3332 || vr1->type == VR_VARYING
3333 || vr1->type == VR_UNDEFINED)
3336 /* Anti-ranges need to be handled separately. */
3337 if (vr0->type == VR_ANTI_RANGE || vr1->type == VR_ANTI_RANGE)
3339 /* If both are anti-ranges, then we cannot compute any
3341 if (vr0->type == VR_ANTI_RANGE && vr1->type == VR_ANTI_RANGE)
3344 /* These comparisons are never statically computable. */
3351 /* Equality can be computed only between a range and an
3352 anti-range. ~[VAL1, VAL2] == [VAL1, VAL2] is always false. */
3353 if (vr0->type == VR_RANGE)
3355 /* To simplify processing, make VR0 the anti-range. */
3356 value_range_t *tmp = vr0;
3361 gcc_assert (comp == NE_EXPR || comp == EQ_EXPR);
3363 if (compare_values_warnv (vr0->min, vr1->min, strict_overflow_p) == 0
3364 && compare_values_warnv (vr0->max, vr1->max, strict_overflow_p) == 0)
3365 return (comp == NE_EXPR) ? boolean_true_node : boolean_false_node;
3370 if (!usable_range_p (vr0, strict_overflow_p)
3371 || !usable_range_p (vr1, strict_overflow_p))
3374 /* Simplify processing. If COMP is GT_EXPR or GE_EXPR, switch the
3375 operands around and change the comparison code. */
3376 if (comp == GT_EXPR || comp == GE_EXPR)
3379 comp = (comp == GT_EXPR) ? LT_EXPR : LE_EXPR;
3385 if (comp == EQ_EXPR)
3387 /* Equality may only be computed if both ranges represent
3388 exactly one value. */
3389 if (compare_values_warnv (vr0->min, vr0->max, strict_overflow_p) == 0
3390 && compare_values_warnv (vr1->min, vr1->max, strict_overflow_p) == 0)
3392 int cmp_min = compare_values_warnv (vr0->min, vr1->min,
3394 int cmp_max = compare_values_warnv (vr0->max, vr1->max,
3396 if (cmp_min == 0 && cmp_max == 0)
3397 return boolean_true_node;
3398 else if (cmp_min != -2 && cmp_max != -2)
3399 return boolean_false_node;
3401 /* If [V0_MIN, V1_MAX] < [V1_MIN, V1_MAX] then V0 != V1. */
3402 else if (compare_values_warnv (vr0->min, vr1->max,
3403 strict_overflow_p) == 1
3404 || compare_values_warnv (vr1->min, vr0->max,
3405 strict_overflow_p) == 1)
3406 return boolean_false_node;
3410 else if (comp == NE_EXPR)
3414 /* If VR0 is completely to the left or completely to the right
3415 of VR1, they are always different. Notice that we need to
3416 make sure that both comparisons yield similar results to
3417 avoid comparing values that cannot be compared at
3419 cmp1 = compare_values_warnv (vr0->max, vr1->min, strict_overflow_p);
3420 cmp2 = compare_values_warnv (vr0->min, vr1->max, strict_overflow_p);
3421 if ((cmp1 == -1 && cmp2 == -1) || (cmp1 == 1 && cmp2 == 1))
3422 return boolean_true_node;
3424 /* If VR0 and VR1 represent a single value and are identical,
3426 else if (compare_values_warnv (vr0->min, vr0->max,
3427 strict_overflow_p) == 0
3428 && compare_values_warnv (vr1->min, vr1->max,
3429 strict_overflow_p) == 0
3430 && compare_values_warnv (vr0->min, vr1->min,
3431 strict_overflow_p) == 0
3432 && compare_values_warnv (vr0->max, vr1->max,
3433 strict_overflow_p) == 0)
3434 return boolean_false_node;
3436 /* Otherwise, they may or may not be different. */
3440 else if (comp == LT_EXPR || comp == LE_EXPR)
3444 /* If VR0 is to the left of VR1, return true. */
3445 tst = compare_values_warnv (vr0->max, vr1->min, strict_overflow_p);
3446 if ((comp == LT_EXPR && tst == -1)
3447 || (comp == LE_EXPR && (tst == -1 || tst == 0)))
3449 if (overflow_infinity_range_p (vr0)
3450 || overflow_infinity_range_p (vr1))
3451 *strict_overflow_p = true;
3452 return boolean_true_node;
3455 /* If VR0 is to the right of VR1, return false. */
3456 tst = compare_values_warnv (vr0->min, vr1->max, strict_overflow_p);
3457 if ((comp == LT_EXPR && (tst == 0 || tst == 1))
3458 || (comp == LE_EXPR && tst == 1))
3460 if (overflow_infinity_range_p (vr0)
3461 || overflow_infinity_range_p (vr1))
3462 *strict_overflow_p = true;
3463 return boolean_false_node;
3466 /* Otherwise, we don't know. */
3474 /* Given a value range VR, a value VAL and a comparison code COMP, return
3475 BOOLEAN_TRUE_NODE if VR COMP VAL always returns true for all the
3476 values in VR. Return BOOLEAN_FALSE_NODE if the comparison
3477 always returns false. Return NULL_TREE if it is not always
3478 possible to determine the value of the comparison. Also set
3479 *STRICT_OVERFLOW_P to indicate whether a range with an overflow
3480 infinity was used in the test. */
3483 compare_range_with_value (enum tree_code comp, value_range_t *vr, tree val,
3484 bool *strict_overflow_p)
3486 if (vr->type == VR_VARYING || vr->type == VR_UNDEFINED)
3489 /* Anti-ranges need to be handled separately. */
3490 if (vr->type == VR_ANTI_RANGE)
3492 /* For anti-ranges, the only predicates that we can compute at
3493 compile time are equality and inequality. */
3500 /* ~[VAL_1, VAL_2] OP VAL is known if VAL_1 <= VAL <= VAL_2. */
3501 if (value_inside_range (val, vr) == 1)
3502 return (comp == NE_EXPR) ? boolean_true_node : boolean_false_node;
3507 if (!usable_range_p (vr, strict_overflow_p))
3510 if (comp == EQ_EXPR)
3512 /* EQ_EXPR may only be computed if VR represents exactly
3514 if (compare_values_warnv (vr->min, vr->max, strict_overflow_p) == 0)
3516 int cmp = compare_values_warnv (vr->min, val, strict_overflow_p);
3518 return boolean_true_node;
3519 else if (cmp == -1 || cmp == 1 || cmp == 2)
3520 return boolean_false_node;
3522 else if (compare_values_warnv (val, vr->min, strict_overflow_p) == -1
3523 || compare_values_warnv (vr->max, val, strict_overflow_p) == -1)
3524 return boolean_false_node;
3528 else if (comp == NE_EXPR)
3530 /* If VAL is not inside VR, then they are always different. */
3531 if (compare_values_warnv (vr->max, val, strict_overflow_p) == -1
3532 || compare_values_warnv (vr->min, val, strict_overflow_p) == 1)
3533 return boolean_true_node;
3535 /* If VR represents exactly one value equal to VAL, then return
3537 if (compare_values_warnv (vr->min, vr->max, strict_overflow_p) == 0
3538 && compare_values_warnv (vr->min, val, strict_overflow_p) == 0)
3539 return boolean_false_node;
3541 /* Otherwise, they may or may not be different. */
3544 else if (comp == LT_EXPR || comp == LE_EXPR)
3548 /* If VR is to the left of VAL, return true. */
3549 tst = compare_values_warnv (vr->max, val, strict_overflow_p);
3550 if ((comp == LT_EXPR && tst == -1)
3551 || (comp == LE_EXPR && (tst == -1 || tst == 0)))
3553 if (overflow_infinity_range_p (vr))
3554 *strict_overflow_p = true;
3555 return boolean_true_node;
3558 /* If VR is to the right of VAL, return false. */
3559 tst = compare_values_warnv (vr->min, val, strict_overflow_p);
3560 if ((comp == LT_EXPR && (tst == 0 || tst == 1))
3561 || (comp == LE_EXPR && tst == 1))
3563 if (overflow_infinity_range_p (vr))
3564 *strict_overflow_p = true;
3565 return boolean_false_node;
3568 /* Otherwise, we don't know. */
3571 else if (comp == GT_EXPR || comp == GE_EXPR)
3575 /* If VR is to the right of VAL, return true. */
3576 tst = compare_values_warnv (vr->min, val, strict_overflow_p);
3577 if ((comp == GT_EXPR && tst == 1)
3578 || (comp == GE_EXPR && (tst == 0 || tst == 1)))
3580 if (overflow_infinity_range_p (vr))
3581 *strict_overflow_p = true;
3582 return boolean_true_node;
3585 /* If VR is to the left of VAL, return false. */
3586 tst = compare_values_warnv (vr->max, val, strict_overflow_p);
3587 if ((comp == GT_EXPR && (tst == -1 || tst == 0))
3588 || (comp == GE_EXPR && tst == -1))
3590 if (overflow_infinity_range_p (vr))
3591 *strict_overflow_p = true;
3592 return boolean_false_node;
3595 /* Otherwise, we don't know. */
3603 /* Debugging dumps. */
3605 void dump_value_range (FILE *, value_range_t *);
3606 void debug_value_range (value_range_t *);
3607 void dump_all_value_ranges (FILE *);
3608 void debug_all_value_ranges (void);
3609 void dump_vr_equiv (FILE *, bitmap);
3610 void debug_vr_equiv (bitmap);
3613 /* Dump value range VR to FILE. */
3616 dump_value_range (FILE *file, value_range_t *vr)
3619 fprintf (file, "[]");
3620 else if (vr->type == VR_UNDEFINED)
3621 fprintf (file, "UNDEFINED");
3622 else if (vr->type == VR_RANGE || vr->type == VR_ANTI_RANGE)
3624 tree type = TREE_TYPE (vr->min);
3626 fprintf (file, "%s[", (vr->type == VR_ANTI_RANGE) ? "~" : "");
3628 if (is_negative_overflow_infinity (vr->min))
3629 fprintf (file, "-INF(OVF)");
3630 else if (INTEGRAL_TYPE_P (type)
3631 && !TYPE_UNSIGNED (type)
3632 && vrp_val_is_min (vr->min))
3633 fprintf (file, "-INF");
3635 print_generic_expr (file, vr->min, 0);
3637 fprintf (file, ", ");
3639 if (is_positive_overflow_infinity (vr->max))
3640 fprintf (file, "+INF(OVF)");
3641 else if (INTEGRAL_TYPE_P (type)
3642 && vrp_val_is_max (vr->max))
3643 fprintf (file, "+INF");
3645 print_generic_expr (file, vr->max, 0);
3647 fprintf (file, "]");
3654 fprintf (file, " EQUIVALENCES: { ");
3656 EXECUTE_IF_SET_IN_BITMAP (vr->equiv, 0, i, bi)
3658 print_generic_expr (file, ssa_name (i), 0);
3659 fprintf (file, " ");
3663 fprintf (file, "} (%u elements)", c);
3666 else if (vr->type == VR_VARYING)
3667 fprintf (file, "VARYING");
3669 fprintf (file, "INVALID RANGE");
3673 /* Dump value range VR to stderr. */
3676 debug_value_range (value_range_t *vr)
3678 dump_value_range (stderr, vr);
3679 fprintf (stderr, "\n");
3683 /* Dump value ranges of all SSA_NAMEs to FILE. */
3686 dump_all_value_ranges (FILE *file)
3690 for (i = 0; i < num_ssa_names; i++)
3694 print_generic_expr (file, ssa_name (i), 0);
3695 fprintf (file, ": ");
3696 dump_value_range (file, vr_value[i]);
3697 fprintf (file, "\n");
3701 fprintf (file, "\n");
3705 /* Dump all value ranges to stderr. */
3708 debug_all_value_ranges (void)
3710 dump_all_value_ranges (stderr);
3714 /* Given a COND_EXPR COND of the form 'V OP W', and an SSA name V,
3715 create a new SSA name N and return the assertion assignment
3716 'V = ASSERT_EXPR <V, V OP W>'. */
3719 build_assert_expr_for (tree cond, tree v)
3724 gcc_assert (TREE_CODE (v) == SSA_NAME);
3725 n = duplicate_ssa_name (v, NULL);
3727 if (COMPARISON_CLASS_P (cond))
3729 tree a = build2 (ASSERT_EXPR, TREE_TYPE (v), v, cond);
3730 assertion = gimple_build_assign (n, a);
3732 else if (TREE_CODE (cond) == TRUTH_NOT_EXPR)
3734 /* Given !V, build the assignment N = false. */
3735 tree op0 = TREE_OPERAND (cond, 0);
3736 gcc_assert (op0 == v);
3737 assertion = gimple_build_assign (n, boolean_false_node);
3739 else if (TREE_CODE (cond) == SSA_NAME)
3741 /* Given V, build the assignment N = true. */
3742 gcc_assert (v == cond);
3743 assertion = gimple_build_assign (n, boolean_true_node);
3748 SSA_NAME_DEF_STMT (n) = assertion;
3750 /* The new ASSERT_EXPR, creates a new SSA name that replaces the
3751 operand of the ASSERT_EXPR. Register the new name and the old one
3752 in the replacement table so that we can fix the SSA web after
3753 adding all the ASSERT_EXPRs. */
3754 register_new_name_mapping (n, v);
3760 /* Return false if EXPR is a predicate expression involving floating
3764 fp_predicate (gimple stmt)
3766 GIMPLE_CHECK (stmt, GIMPLE_COND);
3768 return FLOAT_TYPE_P (TREE_TYPE (gimple_cond_lhs (stmt)));
3772 /* If the range of values taken by OP can be inferred after STMT executes,
3773 return the comparison code (COMP_CODE_P) and value (VAL_P) that
3774 describes the inferred range. Return true if a range could be
3778 infer_value_range (gimple stmt, tree op, enum tree_code *comp_code_p, tree *val_p)
3781 *comp_code_p = ERROR_MARK;
3783 /* Do not attempt to infer anything in names that flow through
3785 if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (op))
3788 /* Similarly, don't infer anything from statements that may throw
3790 if (stmt_could_throw_p (stmt))
3793 /* If STMT is the last statement of a basic block with no
3794 successors, there is no point inferring anything about any of its
3795 operands. We would not be able to find a proper insertion point
3796 for the assertion, anyway. */
3797 if (stmt_ends_bb_p (stmt) && EDGE_COUNT (gimple_bb (stmt)->succs) == 0)
3800 /* We can only assume that a pointer dereference will yield
3801 non-NULL if -fdelete-null-pointer-checks is enabled. */
3802 if (flag_delete_null_pointer_checks
3803 && POINTER_TYPE_P (TREE_TYPE (op))
3804 && gimple_code (stmt) != GIMPLE_ASM)
3806 unsigned num_uses, num_loads, num_stores;
3808 count_uses_and_derefs (op, stmt, &num_uses, &num_loads, &num_stores);
3809 if (num_loads + num_stores > 0)
3811 *val_p = build_int_cst (TREE_TYPE (op), 0);
3812 *comp_code_p = NE_EXPR;
3821 void dump_asserts_for (FILE *, tree);
3822 void debug_asserts_for (tree);
3823 void dump_all_asserts (FILE *);
3824 void debug_all_asserts (void);
3826 /* Dump all the registered assertions for NAME to FILE. */
3829 dump_asserts_for (FILE *file, tree name)
3833 fprintf (file, "Assertions to be inserted for ");
3834 print_generic_expr (file, name, 0);
3835 fprintf (file, "\n");
3837 loc = asserts_for[SSA_NAME_VERSION (name)];
3840 fprintf (file, "\t");
3841 print_gimple_stmt (file, gsi_stmt (loc->si), 0, 0);
3842 fprintf (file, "\n\tBB #%d", loc->bb->index);
3845 fprintf (file, "\n\tEDGE %d->%d", loc->e->src->index,
3846 loc->e->dest->index);
3847 dump_edge_info (file, loc->e, 0);
3849 fprintf (file, "\n\tPREDICATE: ");
3850 print_generic_expr (file, name, 0);
3851 fprintf (file, " %s ", tree_code_name[(int)loc->comp_code]);
3852 print_generic_expr (file, loc->val, 0);
3853 fprintf (file, "\n\n");
3857 fprintf (file, "\n");
3861 /* Dump all the registered assertions for NAME to stderr. */
3864 debug_asserts_for (tree name)
3866 dump_asserts_for (stderr, name);
3870 /* Dump all the registered assertions for all the names to FILE. */
3873 dump_all_asserts (FILE *file)
3878 fprintf (file, "\nASSERT_EXPRs to be inserted\n\n");
3879 EXECUTE_IF_SET_IN_BITMAP (need_assert_for, 0, i, bi)
3880 dump_asserts_for (file, ssa_name (i));
3881 fprintf (file, "\n");
3885 /* Dump all the registered assertions for all the names to stderr. */
3888 debug_all_asserts (void)
3890 dump_all_asserts (stderr);
3894 /* If NAME doesn't have an ASSERT_EXPR registered for asserting
3895 'EXPR COMP_CODE VAL' at a location that dominates block BB or
3896 E->DEST, then register this location as a possible insertion point
3897 for ASSERT_EXPR <NAME, EXPR COMP_CODE VAL>.
3899 BB, E and SI provide the exact insertion point for the new
3900 ASSERT_EXPR. If BB is NULL, then the ASSERT_EXPR is to be inserted
3901 on edge E. Otherwise, if E is NULL, the ASSERT_EXPR is inserted on
3902 BB. If SI points to a COND_EXPR or a SWITCH_EXPR statement, then E
3903 must not be NULL. */
3906 register_new_assert_for (tree name, tree expr,
3907 enum tree_code comp_code,
3911 gimple_stmt_iterator si)
3913 assert_locus_t n, loc, last_loc;
3915 basic_block dest_bb;
3917 #if defined ENABLE_CHECKING
3918 gcc_assert (bb == NULL || e == NULL);
3921 gcc_assert (gimple_code (gsi_stmt (si)) != GIMPLE_COND
3922 && gimple_code (gsi_stmt (si)) != GIMPLE_SWITCH);
3925 /* Never build an assert comparing against an integer constant with
3926 TREE_OVERFLOW set. This confuses our undefined overflow warning
3928 if (TREE_CODE (val) == INTEGER_CST
3929 && TREE_OVERFLOW (val))
3930 val = build_int_cst_wide (TREE_TYPE (val),
3931 TREE_INT_CST_LOW (val), TREE_INT_CST_HIGH (val));
3933 /* The new assertion A will be inserted at BB or E. We need to
3934 determine if the new location is dominated by a previously
3935 registered location for A. If we are doing an edge insertion,
3936 assume that A will be inserted at E->DEST. Note that this is not
3939 If E is a critical edge, it will be split. But even if E is
3940 split, the new block will dominate the same set of blocks that
3943 The reverse, however, is not true, blocks dominated by E->DEST
3944 will not be dominated by the new block created to split E. So,
3945 if the insertion location is on a critical edge, we will not use
3946 the new location to move another assertion previously registered
3947 at a block dominated by E->DEST. */
3948 dest_bb = (bb) ? bb : e->dest;
3950 /* If NAME already has an ASSERT_EXPR registered for COMP_CODE and
3951 VAL at a block dominating DEST_BB, then we don't need to insert a new
3952 one. Similarly, if the same assertion already exists at a block
3953 dominated by DEST_BB and the new location is not on a critical
3954 edge, then update the existing location for the assertion (i.e.,
3955 move the assertion up in the dominance tree).
3957 Note, this is implemented as a simple linked list because there
3958 should not be more than a handful of assertions registered per
3959 name. If this becomes a performance problem, a table hashed by
3960 COMP_CODE and VAL could be implemented. */
3961 loc = asserts_for[SSA_NAME_VERSION (name)];
3966 if (loc->comp_code == comp_code
3968 || operand_equal_p (loc->val, val, 0))
3969 && (loc->expr == expr
3970 || operand_equal_p (loc->expr, expr, 0)))
3972 /* If the assertion NAME COMP_CODE VAL has already been
3973 registered at a basic block that dominates DEST_BB, then
3974 we don't need to insert the same assertion again. Note
3975 that we don't check strict dominance here to avoid
3976 replicating the same assertion inside the same basic
3977 block more than once (e.g., when a pointer is
3978 dereferenced several times inside a block).
3980 An exception to this rule are edge insertions. If the
3981 new assertion is to be inserted on edge E, then it will
3982 dominate all the other insertions that we may want to
3983 insert in DEST_BB. So, if we are doing an edge
3984 insertion, don't do this dominance check. */
3986 && dominated_by_p (CDI_DOMINATORS, dest_bb, loc->bb))
3989 /* Otherwise, if E is not a critical edge and DEST_BB
3990 dominates the existing location for the assertion, move
3991 the assertion up in the dominance tree by updating its
3992 location information. */
3993 if ((e == NULL || !EDGE_CRITICAL_P (e))
3994 && dominated_by_p (CDI_DOMINATORS, loc->bb, dest_bb))
4003 /* Update the last node of the list and move to the next one. */
4008 /* If we didn't find an assertion already registered for
4009 NAME COMP_CODE VAL, add a new one at the end of the list of
4010 assertions associated with NAME. */
4011 n = XNEW (struct assert_locus_d);
4015 n->comp_code = comp_code;
4023 asserts_for[SSA_NAME_VERSION (name)] = n;
4025 bitmap_set_bit (need_assert_for, SSA_NAME_VERSION (name));
4028 /* (COND_OP0 COND_CODE COND_OP1) is a predicate which uses NAME.
4029 Extract a suitable test code and value and store them into *CODE_P and
4030 *VAL_P so the predicate is normalized to NAME *CODE_P *VAL_P.
4032 If no extraction was possible, return FALSE, otherwise return TRUE.
4034 If INVERT is true, then we invert the result stored into *CODE_P. */
4037 extract_code_and_val_from_cond_with_ops (tree name, enum tree_code cond_code,
4038 tree cond_op0, tree cond_op1,
4039 bool invert, enum tree_code *code_p,
4042 enum tree_code comp_code;
4045 /* Otherwise, we have a comparison of the form NAME COMP VAL
4046 or VAL COMP NAME. */
4047 if (name == cond_op1)
4049 /* If the predicate is of the form VAL COMP NAME, flip
4050 COMP around because we need to register NAME as the
4051 first operand in the predicate. */
4052 comp_code = swap_tree_comparison (cond_code);
4057 /* The comparison is of the form NAME COMP VAL, so the
4058 comparison code remains unchanged. */
4059 comp_code = cond_code;
4063 /* Invert the comparison code as necessary. */
4065 comp_code = invert_tree_comparison (comp_code, 0);
4067 /* VRP does not handle float types. */
4068 if (SCALAR_FLOAT_TYPE_P (TREE_TYPE (val)))
4071 /* Do not register always-false predicates.
4072 FIXME: this works around a limitation in fold() when dealing with
4073 enumerations. Given 'enum { N1, N2 } x;', fold will not
4074 fold 'if (x > N2)' to 'if (0)'. */
4075 if ((comp_code == GT_EXPR || comp_code == LT_EXPR)
4076 && INTEGRAL_TYPE_P (TREE_TYPE (val)))
4078 tree min = TYPE_MIN_VALUE (TREE_TYPE (val));
4079 tree max = TYPE_MAX_VALUE (TREE_TYPE (val));
4081 if (comp_code == GT_EXPR
4083 || compare_values (val, max) == 0))
4086 if (comp_code == LT_EXPR
4088 || compare_values (val, min) == 0))
4091 *code_p = comp_code;
4096 /* Try to register an edge assertion for SSA name NAME on edge E for
4097 the condition COND contributing to the conditional jump pointed to by BSI.
4098 Invert the condition COND if INVERT is true.
4099 Return true if an assertion for NAME could be registered. */
4102 register_edge_assert_for_2 (tree name, edge e, gimple_stmt_iterator bsi,
4103 enum tree_code cond_code,
4104 tree cond_op0, tree cond_op1, bool invert)
4107 enum tree_code comp_code;
4108 bool retval = false;
4110 if (!extract_code_and_val_from_cond_with_ops (name, cond_code,
4113 invert, &comp_code, &val))
4116 /* Only register an ASSERT_EXPR if NAME was found in the sub-graph
4117 reachable from E. */
4118 if (live_on_edge (e, name)
4119 && !has_single_use (name))
4121 register_new_assert_for (name, name, comp_code, val, NULL, e, bsi);
4125 /* In the case of NAME <= CST and NAME being defined as
4126 NAME = (unsigned) NAME2 + CST2 we can assert NAME2 >= -CST2
4127 and NAME2 <= CST - CST2. We can do the same for NAME > CST.
4128 This catches range and anti-range tests. */
4129 if ((comp_code == LE_EXPR
4130 || comp_code == GT_EXPR)
4131 && TREE_CODE (val) == INTEGER_CST
4132 && TYPE_UNSIGNED (TREE_TYPE (val)))
4134 gimple def_stmt = SSA_NAME_DEF_STMT (name);
4135 tree cst2 = NULL_TREE, name2 = NULL_TREE, name3 = NULL_TREE;
4137 /* Extract CST2 from the (optional) addition. */
4138 if (is_gimple_assign (def_stmt)
4139 && gimple_assign_rhs_code (def_stmt) == PLUS_EXPR)
4141 name2 = gimple_assign_rhs1 (def_stmt);
4142 cst2 = gimple_assign_rhs2 (def_stmt);
4143 if (TREE_CODE (name2) == SSA_NAME
4144 && TREE_CODE (cst2) == INTEGER_CST)
4145 def_stmt = SSA_NAME_DEF_STMT (name2);
4148 /* Extract NAME2 from the (optional) sign-changing cast. */
4149 if (gimple_assign_cast_p (def_stmt))
4151 if (CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (def_stmt))
4152 && ! TYPE_UNSIGNED (TREE_TYPE (gimple_assign_rhs1 (def_stmt)))
4153 && (TYPE_PRECISION (gimple_expr_type (def_stmt))
4154 == TYPE_PRECISION (TREE_TYPE (gimple_assign_rhs1 (def_stmt)))))
4155 name3 = gimple_assign_rhs1 (def_stmt);
4158 /* If name3 is used later, create an ASSERT_EXPR for it. */
4159 if (name3 != NULL_TREE
4160 && TREE_CODE (name3) == SSA_NAME
4161 && (cst2 == NULL_TREE
4162 || TREE_CODE (cst2) == INTEGER_CST)
4163 && INTEGRAL_TYPE_P (TREE_TYPE (name3))
4164 && live_on_edge (e, name3)
4165 && !has_single_use (name3))
4169 /* Build an expression for the range test. */
4170 tmp = build1 (NOP_EXPR, TREE_TYPE (name), name3);
4171 if (cst2 != NULL_TREE)
4172 tmp = build2 (PLUS_EXPR, TREE_TYPE (name), tmp, cst2);
4176 fprintf (dump_file, "Adding assert for ");
4177 print_generic_expr (dump_file, name3, 0);
4178 fprintf (dump_file, " from ");
4179 print_generic_expr (dump_file, tmp, 0);
4180 fprintf (dump_file, "\n");
4183 register_new_assert_for (name3, tmp, comp_code, val, NULL, e, bsi);
4188 /* If name2 is used later, create an ASSERT_EXPR for it. */
4189 if (name2 != NULL_TREE
4190 && TREE_CODE (name2) == SSA_NAME
4191 && TREE_CODE (cst2) == INTEGER_CST
4192 && INTEGRAL_TYPE_P (TREE_TYPE (name2))
4193 && live_on_edge (e, name2)
4194 && !has_single_use (name2))
4198 /* Build an expression for the range test. */
4200 if (TREE_TYPE (name) != TREE_TYPE (name2))
4201 tmp = build1 (NOP_EXPR, TREE_TYPE (name), tmp);
4202 if (cst2 != NULL_TREE)
4203 tmp = build2 (PLUS_EXPR, TREE_TYPE (name), tmp, cst2);
4207 fprintf (dump_file, "Adding assert for ");
4208 print_generic_expr (dump_file, name2, 0);
4209 fprintf (dump_file, " from ");
4210 print_generic_expr (dump_file, tmp, 0);
4211 fprintf (dump_file, "\n");
4214 register_new_assert_for (name2, tmp, comp_code, val, NULL, e, bsi);
4223 /* OP is an operand of a truth value expression which is known to have
4224 a particular value. Register any asserts for OP and for any
4225 operands in OP's defining statement.
4227 If CODE is EQ_EXPR, then we want to register OP is zero (false),
4228 if CODE is NE_EXPR, then we want to register OP is nonzero (true). */
4231 register_edge_assert_for_1 (tree op, enum tree_code code,
4232 edge e, gimple_stmt_iterator bsi)
4234 bool retval = false;
4237 enum tree_code rhs_code;
4239 /* We only care about SSA_NAMEs. */
4240 if (TREE_CODE (op) != SSA_NAME)
4243 /* We know that OP will have a zero or nonzero value. If OP is used
4244 more than once go ahead and register an assert for OP.
4246 The FOUND_IN_SUBGRAPH support is not helpful in this situation as
4247 it will always be set for OP (because OP is used in a COND_EXPR in
4249 if (!has_single_use (op))
4251 val = build_int_cst (TREE_TYPE (op), 0);
4252 register_new_assert_for (op, op, code, val, NULL, e, bsi);
4256 /* Now look at how OP is set. If it's set from a comparison,
4257 a truth operation or some bit operations, then we may be able
4258 to register information about the operands of that assignment. */
4259 op_def = SSA_NAME_DEF_STMT (op);
4260 if (gimple_code (op_def) != GIMPLE_ASSIGN)
4263 rhs_code = gimple_assign_rhs_code (op_def);
4265 if (TREE_CODE_CLASS (rhs_code) == tcc_comparison)
4267 bool invert = (code == EQ_EXPR ? true : false);
4268 tree op0 = gimple_assign_rhs1 (op_def);
4269 tree op1 = gimple_assign_rhs2 (op_def);
4271 if (TREE_CODE (op0) == SSA_NAME)
4272 retval |= register_edge_assert_for_2 (op0, e, bsi, rhs_code, op0, op1,
4274 if (TREE_CODE (op1) == SSA_NAME)
4275 retval |= register_edge_assert_for_2 (op1, e, bsi, rhs_code, op0, op1,
4278 else if ((code == NE_EXPR
4279 && (gimple_assign_rhs_code (op_def) == TRUTH_AND_EXPR
4280 || gimple_assign_rhs_code (op_def) == BIT_AND_EXPR))
4282 && (gimple_assign_rhs_code (op_def) == TRUTH_OR_EXPR
4283 || gimple_assign_rhs_code (op_def) == BIT_IOR_EXPR)))
4285 /* Recurse on each operand. */
4286 retval |= register_edge_assert_for_1 (gimple_assign_rhs1 (op_def),
4288 retval |= register_edge_assert_for_1 (gimple_assign_rhs2 (op_def),
4291 else if (gimple_assign_rhs_code (op_def) == TRUTH_NOT_EXPR)
4293 /* Recurse, flipping CODE. */
4294 code = invert_tree_comparison (code, false);
4295 retval |= register_edge_assert_for_1 (gimple_assign_rhs1 (op_def),
4298 else if (gimple_assign_rhs_code (op_def) == SSA_NAME)
4300 /* Recurse through the copy. */
4301 retval |= register_edge_assert_for_1 (gimple_assign_rhs1 (op_def),
4304 else if (CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (op_def)))
4306 /* Recurse through the type conversion. */
4307 retval |= register_edge_assert_for_1 (gimple_assign_rhs1 (op_def),
4314 /* Try to register an edge assertion for SSA name NAME on edge E for
4315 the condition COND contributing to the conditional jump pointed to by SI.
4316 Return true if an assertion for NAME could be registered. */
4319 register_edge_assert_for (tree name, edge e, gimple_stmt_iterator si,
4320 enum tree_code cond_code, tree cond_op0,
4324 enum tree_code comp_code;
4325 bool retval = false;
4326 bool is_else_edge = (e->flags & EDGE_FALSE_VALUE) != 0;
4328 /* Do not attempt to infer anything in names that flow through
4330 if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (name))
4333 if (!extract_code_and_val_from_cond_with_ops (name, cond_code,
4339 /* Register ASSERT_EXPRs for name. */
4340 retval |= register_edge_assert_for_2 (name, e, si, cond_code, cond_op0,
4341 cond_op1, is_else_edge);
4344 /* If COND is effectively an equality test of an SSA_NAME against
4345 the value zero or one, then we may be able to assert values
4346 for SSA_NAMEs which flow into COND. */
4348 /* In the case of NAME == 1 or NAME != 0, for TRUTH_AND_EXPR defining
4349 statement of NAME we can assert both operands of the TRUTH_AND_EXPR
4350 have nonzero value. */
4351 if (((comp_code == EQ_EXPR && integer_onep (val))
4352 || (comp_code == NE_EXPR && integer_zerop (val))))
4354 gimple def_stmt = SSA_NAME_DEF_STMT (name);
4356 if (is_gimple_assign (def_stmt)
4357 && (gimple_assign_rhs_code (def_stmt) == TRUTH_AND_EXPR
4358 || gimple_assign_rhs_code (def_stmt) == BIT_AND_EXPR))
4360 tree op0 = gimple_assign_rhs1 (def_stmt);
4361 tree op1 = gimple_assign_rhs2 (def_stmt);
4362 retval |= register_edge_assert_for_1 (op0, NE_EXPR, e, si);
4363 retval |= register_edge_assert_for_1 (op1, NE_EXPR, e, si);
4367 /* In the case of NAME == 0 or NAME != 1, for TRUTH_OR_EXPR defining
4368 statement of NAME we can assert both operands of the TRUTH_OR_EXPR
4370 if (((comp_code == EQ_EXPR && integer_zerop (val))
4371 || (comp_code == NE_EXPR && integer_onep (val))))
4373 gimple def_stmt = SSA_NAME_DEF_STMT (name);
4375 if (is_gimple_assign (def_stmt)
4376 && (gimple_assign_rhs_code (def_stmt) == TRUTH_OR_EXPR
4377 /* For BIT_IOR_EXPR only if NAME == 0 both operands have
4378 necessarily zero value. */
4379 || (comp_code == EQ_EXPR
4380 && (gimple_assign_rhs_code (def_stmt) == BIT_IOR_EXPR))))
4382 tree op0 = gimple_assign_rhs1 (def_stmt);
4383 tree op1 = gimple_assign_rhs2 (def_stmt);
4384 retval |= register_edge_assert_for_1 (op0, EQ_EXPR, e, si);
4385 retval |= register_edge_assert_for_1 (op1, EQ_EXPR, e, si);
4393 /* Determine whether the outgoing edges of BB should receive an
4394 ASSERT_EXPR for each of the operands of BB's LAST statement.
4395 The last statement of BB must be a COND_EXPR.
4397 If any of the sub-graphs rooted at BB have an interesting use of
4398 the predicate operands, an assert location node is added to the
4399 list of assertions for the corresponding operands. */
4402 find_conditional_asserts (basic_block bb, gimple last)
4405 gimple_stmt_iterator bsi;
4411 need_assert = false;
4412 bsi = gsi_for_stmt (last);
4414 /* Look for uses of the operands in each of the sub-graphs
4415 rooted at BB. We need to check each of the outgoing edges
4416 separately, so that we know what kind of ASSERT_EXPR to
4418 FOR_EACH_EDGE (e, ei, bb->succs)
4423 /* Register the necessary assertions for each operand in the
4424 conditional predicate. */
4425 FOR_EACH_SSA_TREE_OPERAND (op, last, iter, SSA_OP_USE)
4427 need_assert |= register_edge_assert_for (op, e, bsi,
4428 gimple_cond_code (last),
4429 gimple_cond_lhs (last),
4430 gimple_cond_rhs (last));
4437 /* Compare two case labels sorting first by the destination label uid
4438 and then by the case value. */
4441 compare_case_labels (const void *p1, const void *p2)
4443 const_tree const case1 = *(const_tree const*)p1;
4444 const_tree const case2 = *(const_tree const*)p2;
4445 unsigned int uid1 = DECL_UID (CASE_LABEL (case1));
4446 unsigned int uid2 = DECL_UID (CASE_LABEL (case2));
4450 else if (uid1 == uid2)
4452 /* Make sure the default label is first in a group. */
4453 if (!CASE_LOW (case1))
4455 else if (!CASE_LOW (case2))
4458 return tree_int_cst_compare (CASE_LOW (case1), CASE_LOW (case2));
4464 /* Determine whether the outgoing edges of BB should receive an
4465 ASSERT_EXPR for each of the operands of BB's LAST statement.
4466 The last statement of BB must be a SWITCH_EXPR.
4468 If any of the sub-graphs rooted at BB have an interesting use of
4469 the predicate operands, an assert location node is added to the
4470 list of assertions for the corresponding operands. */
4473 find_switch_asserts (basic_block bb, gimple last)
4476 gimple_stmt_iterator bsi;
4480 size_t n = gimple_switch_num_labels(last);
4481 #if GCC_VERSION >= 4000
4484 /* Work around GCC 3.4 bug (PR 37086). */
4485 volatile unsigned int idx;
4488 need_assert = false;
4489 bsi = gsi_for_stmt (last);
4490 op = gimple_switch_index (last);
4491 if (TREE_CODE (op) != SSA_NAME)
4494 /* Build a vector of case labels sorted by destination label. */
4495 vec2 = make_tree_vec (n);
4496 for (idx = 0; idx < n; ++idx)
4497 TREE_VEC_ELT (vec2, idx) = gimple_switch_label (last, idx);
4498 qsort (&TREE_VEC_ELT (vec2, 0), n, sizeof (tree), compare_case_labels);
4500 for (idx = 0; idx < n; ++idx)
4503 tree cl = TREE_VEC_ELT (vec2, idx);
4505 min = CASE_LOW (cl);
4506 max = CASE_HIGH (cl);
4508 /* If there are multiple case labels with the same destination
4509 we need to combine them to a single value range for the edge. */
4511 && CASE_LABEL (cl) == CASE_LABEL (TREE_VEC_ELT (vec2, idx + 1)))
4513 /* Skip labels until the last of the group. */
4517 && CASE_LABEL (cl) == CASE_LABEL (TREE_VEC_ELT (vec2, idx)));
4520 /* Pick up the maximum of the case label range. */
4521 if (CASE_HIGH (TREE_VEC_ELT (vec2, idx)))
4522 max = CASE_HIGH (TREE_VEC_ELT (vec2, idx));
4524 max = CASE_LOW (TREE_VEC_ELT (vec2, idx));
4527 /* Nothing to do if the range includes the default label until we
4528 can register anti-ranges. */
4529 if (min == NULL_TREE)
4532 /* Find the edge to register the assert expr on. */
4533 e = find_edge (bb, label_to_block (CASE_LABEL (cl)));
4535 /* Register the necessary assertions for the operand in the
4537 need_assert |= register_edge_assert_for (op, e, bsi,
4538 max ? GE_EXPR : EQ_EXPR,
4540 fold_convert (TREE_TYPE (op),
4544 need_assert |= register_edge_assert_for (op, e, bsi, LE_EXPR,
4546 fold_convert (TREE_TYPE (op),
4555 /* Traverse all the statements in block BB looking for statements that
4556 may generate useful assertions for the SSA names in their operand.
4557 If a statement produces a useful assertion A for name N_i, then the
4558 list of assertions already generated for N_i is scanned to
4559 determine if A is actually needed.
4561 If N_i already had the assertion A at a location dominating the
4562 current location, then nothing needs to be done. Otherwise, the
4563 new location for A is recorded instead.
4565 1- For every statement S in BB, all the variables used by S are
4566 added to bitmap FOUND_IN_SUBGRAPH.
4568 2- If statement S uses an operand N in a way that exposes a known
4569 value range for N, then if N was not already generated by an
4570 ASSERT_EXPR, create a new assert location for N. For instance,
4571 if N is a pointer and the statement dereferences it, we can
4572 assume that N is not NULL.
4574 3- COND_EXPRs are a special case of #2. We can derive range
4575 information from the predicate but need to insert different
4576 ASSERT_EXPRs for each of the sub-graphs rooted at the
4577 conditional block. If the last statement of BB is a conditional
4578 expression of the form 'X op Y', then
4580 a) Remove X and Y from the set FOUND_IN_SUBGRAPH.
4582 b) If the conditional is the only entry point to the sub-graph
4583 corresponding to the THEN_CLAUSE, recurse into it. On
4584 return, if X and/or Y are marked in FOUND_IN_SUBGRAPH, then
4585 an ASSERT_EXPR is added for the corresponding variable.
4587 c) Repeat step (b) on the ELSE_CLAUSE.
4589 d) Mark X and Y in FOUND_IN_SUBGRAPH.
4598 In this case, an assertion on the THEN clause is useful to
4599 determine that 'a' is always 9 on that edge. However, an assertion
4600 on the ELSE clause would be unnecessary.
4602 4- If BB does not end in a conditional expression, then we recurse
4603 into BB's dominator children.
4605 At the end of the recursive traversal, every SSA name will have a
4606 list of locations where ASSERT_EXPRs should be added. When a new
4607 location for name N is found, it is registered by calling
4608 register_new_assert_for. That function keeps track of all the
4609 registered assertions to prevent adding unnecessary assertions.
4610 For instance, if a pointer P_4 is dereferenced more than once in a
4611 dominator tree, only the location dominating all the dereference of
4612 P_4 will receive an ASSERT_EXPR.
4614 If this function returns true, then it means that there are names
4615 for which we need to generate ASSERT_EXPRs. Those assertions are
4616 inserted by process_assert_insertions. */
4619 find_assert_locations_1 (basic_block bb, sbitmap live)
4621 gimple_stmt_iterator si;
4626 need_assert = false;
4627 last = last_stmt (bb);
4629 /* If BB's last statement is a conditional statement involving integer
4630 operands, determine if we need to add ASSERT_EXPRs. */
4632 && gimple_code (last) == GIMPLE_COND
4633 && !fp_predicate (last)
4634 && !ZERO_SSA_OPERANDS (last, SSA_OP_USE))
4635 need_assert |= find_conditional_asserts (bb, last);
4637 /* If BB's last statement is a switch statement involving integer
4638 operands, determine if we need to add ASSERT_EXPRs. */
4640 && gimple_code (last) == GIMPLE_SWITCH
4641 && !ZERO_SSA_OPERANDS (last, SSA_OP_USE))
4642 need_assert |= find_switch_asserts (bb, last);
4644 /* Traverse all the statements in BB marking used names and looking
4645 for statements that may infer assertions for their used operands. */
4646 for (si = gsi_start_bb (bb); !gsi_end_p (si); gsi_next (&si))
4652 stmt = gsi_stmt (si);
4654 /* See if we can derive an assertion for any of STMT's operands. */
4655 FOR_EACH_SSA_TREE_OPERAND (op, stmt, i, SSA_OP_USE)
4658 enum tree_code comp_code;
4660 /* Mark OP in our live bitmap. */
4661 SET_BIT (live, SSA_NAME_VERSION (op));
4663 /* If OP is used in such a way that we can infer a value
4664 range for it, and we don't find a previous assertion for
4665 it, create a new assertion location node for OP. */
4666 if (infer_value_range (stmt, op, &comp_code, &value))
4668 /* If we are able to infer a nonzero value range for OP,
4669 then walk backwards through the use-def chain to see if OP
4670 was set via a typecast.
4672 If so, then we can also infer a nonzero value range
4673 for the operand of the NOP_EXPR. */
4674 if (comp_code == NE_EXPR && integer_zerop (value))
4677 gimple def_stmt = SSA_NAME_DEF_STMT (t);
4679 while (is_gimple_assign (def_stmt)
4680 && gimple_assign_rhs_code (def_stmt) == NOP_EXPR
4682 (gimple_assign_rhs1 (def_stmt)) == SSA_NAME
4684 (TREE_TYPE (gimple_assign_rhs1 (def_stmt))))
4686 t = gimple_assign_rhs1 (def_stmt);
4687 def_stmt = SSA_NAME_DEF_STMT (t);
4689 /* Note we want to register the assert for the
4690 operand of the NOP_EXPR after SI, not after the
4692 if (! has_single_use (t))
4694 register_new_assert_for (t, t, comp_code, value,
4701 /* If OP is used only once, namely in this STMT, don't
4702 bother creating an ASSERT_EXPR for it. Such an
4703 ASSERT_EXPR would do nothing but increase compile time. */
4704 if (!has_single_use (op))
4706 register_new_assert_for (op, op, comp_code, value,
4714 /* Traverse all PHI nodes in BB marking used operands. */
4715 for (si = gsi_start_phis (bb); !gsi_end_p(si); gsi_next (&si))
4717 use_operand_p arg_p;
4719 phi = gsi_stmt (si);
4721 FOR_EACH_PHI_ARG (arg_p, phi, i, SSA_OP_USE)
4723 tree arg = USE_FROM_PTR (arg_p);
4724 if (TREE_CODE (arg) == SSA_NAME)
4725 SET_BIT (live, SSA_NAME_VERSION (arg));
4732 /* Do an RPO walk over the function computing SSA name liveness
4733 on-the-fly and deciding on assert expressions to insert.
4734 Returns true if there are assert expressions to be inserted. */
4737 find_assert_locations (void)
4739 int *rpo = XCNEWVEC (int, last_basic_block + NUM_FIXED_BLOCKS);
4740 int *bb_rpo = XCNEWVEC (int, last_basic_block + NUM_FIXED_BLOCKS);
4741 int *last_rpo = XCNEWVEC (int, last_basic_block + NUM_FIXED_BLOCKS);
4745 live = XCNEWVEC (sbitmap, last_basic_block + NUM_FIXED_BLOCKS);
4746 rpo_cnt = pre_and_rev_post_order_compute (NULL, rpo, false);
4747 for (i = 0; i < rpo_cnt; ++i)
4750 need_asserts = false;
4751 for (i = rpo_cnt-1; i >= 0; --i)
4753 basic_block bb = BASIC_BLOCK (rpo[i]);
4759 live[rpo[i]] = sbitmap_alloc (num_ssa_names);
4760 sbitmap_zero (live[rpo[i]]);
4763 /* Process BB and update the live information with uses in
4765 need_asserts |= find_assert_locations_1 (bb, live[rpo[i]]);
4767 /* Merge liveness into the predecessor blocks and free it. */
4768 if (!sbitmap_empty_p (live[rpo[i]]))
4771 FOR_EACH_EDGE (e, ei, bb->preds)
4773 int pred = e->src->index;
4774 if (e->flags & EDGE_DFS_BACK)
4779 live[pred] = sbitmap_alloc (num_ssa_names);
4780 sbitmap_zero (live[pred]);
4782 sbitmap_a_or_b (live[pred], live[pred], live[rpo[i]]);
4784 if (bb_rpo[pred] < pred_rpo)
4785 pred_rpo = bb_rpo[pred];
4788 /* Record the RPO number of the last visited block that needs
4789 live information from this block. */
4790 last_rpo[rpo[i]] = pred_rpo;
4794 sbitmap_free (live[rpo[i]]);
4795 live[rpo[i]] = NULL;
4798 /* We can free all successors live bitmaps if all their
4799 predecessors have been visited already. */
4800 FOR_EACH_EDGE (e, ei, bb->succs)
4801 if (last_rpo[e->dest->index] == i
4802 && live[e->dest->index])
4804 sbitmap_free (live[e->dest->index]);
4805 live[e->dest->index] = NULL;
4810 XDELETEVEC (bb_rpo);
4811 XDELETEVEC (last_rpo);
4812 for (i = 0; i < last_basic_block + NUM_FIXED_BLOCKS; ++i)
4814 sbitmap_free (live[i]);
4817 return need_asserts;
4820 /* Create an ASSERT_EXPR for NAME and insert it in the location
4821 indicated by LOC. Return true if we made any edge insertions. */
4824 process_assert_insertions_for (tree name, assert_locus_t loc)
4826 /* Build the comparison expression NAME_i COMP_CODE VAL. */
4833 cond = build2 (loc->comp_code, boolean_type_node, loc->expr, loc->val);
4834 assert_stmt = build_assert_expr_for (cond, name);
4837 /* We have been asked to insert the assertion on an edge. This
4838 is used only by COND_EXPR and SWITCH_EXPR assertions. */
4839 #if defined ENABLE_CHECKING
4840 gcc_assert (gimple_code (gsi_stmt (loc->si)) == GIMPLE_COND
4841 || gimple_code (gsi_stmt (loc->si)) == GIMPLE_SWITCH);
4844 gsi_insert_on_edge (loc->e, assert_stmt);
4848 /* Otherwise, we can insert right after LOC->SI iff the
4849 statement must not be the last statement in the block. */
4850 stmt = gsi_stmt (loc->si);
4851 if (!stmt_ends_bb_p (stmt))
4853 gsi_insert_after (&loc->si, assert_stmt, GSI_SAME_STMT);
4857 /* If STMT must be the last statement in BB, we can only insert new
4858 assertions on the non-abnormal edge out of BB. Note that since
4859 STMT is not control flow, there may only be one non-abnormal edge
4861 FOR_EACH_EDGE (e, ei, loc->bb->succs)
4862 if (!(e->flags & EDGE_ABNORMAL))
4864 gsi_insert_on_edge (e, assert_stmt);
4872 /* Process all the insertions registered for every name N_i registered
4873 in NEED_ASSERT_FOR. The list of assertions to be inserted are
4874 found in ASSERTS_FOR[i]. */
4877 process_assert_insertions (void)
4881 bool update_edges_p = false;
4882 int num_asserts = 0;
4884 if (dump_file && (dump_flags & TDF_DETAILS))
4885 dump_all_asserts (dump_file);
4887 EXECUTE_IF_SET_IN_BITMAP (need_assert_for, 0, i, bi)
4889 assert_locus_t loc = asserts_for[i];
4894 assert_locus_t next = loc->next;
4895 update_edges_p |= process_assert_insertions_for (ssa_name (i), loc);
4903 gsi_commit_edge_inserts ();
4905 statistics_counter_event (cfun, "Number of ASSERT_EXPR expressions inserted",
4910 /* Traverse the flowgraph looking for conditional jumps to insert range
4911 expressions. These range expressions are meant to provide information
4912 to optimizations that need to reason in terms of value ranges. They
4913 will not be expanded into RTL. For instance, given:
4922 this pass will transform the code into:
4928 x = ASSERT_EXPR <x, x < y>
4933 y = ASSERT_EXPR <y, x <= y>
4937 The idea is that once copy and constant propagation have run, other
4938 optimizations will be able to determine what ranges of values can 'x'
4939 take in different paths of the code, simply by checking the reaching
4940 definition of 'x'. */
4943 insert_range_assertions (void)
4945 need_assert_for = BITMAP_ALLOC (NULL);
4946 asserts_for = XCNEWVEC (assert_locus_t, num_ssa_names);
4948 calculate_dominance_info (CDI_DOMINATORS);
4950 if (find_assert_locations ())
4952 process_assert_insertions ();
4953 update_ssa (TODO_update_ssa_no_phi);
4956 if (dump_file && (dump_flags & TDF_DETAILS))
4958 fprintf (dump_file, "\nSSA form after inserting ASSERT_EXPRs\n");
4959 dump_function_to_file (current_function_decl, dump_file, dump_flags);
4963 BITMAP_FREE (need_assert_for);
4966 /* Checks one ARRAY_REF in REF, located at LOCUS. Ignores flexible arrays
4967 and "struct" hacks. If VRP can determine that the
4968 array subscript is a constant, check if it is outside valid
4969 range. If the array subscript is a RANGE, warn if it is
4970 non-overlapping with valid range.
4971 IGNORE_OFF_BY_ONE is true if the ARRAY_REF is inside a ADDR_EXPR. */
4974 check_array_ref (tree ref, location_t location, bool ignore_off_by_one)
4976 value_range_t* vr = NULL;
4977 tree low_sub, up_sub;
4978 tree low_bound, up_bound = array_ref_up_bound (ref);
4980 low_sub = up_sub = TREE_OPERAND (ref, 1);
4982 if (!up_bound || TREE_NO_WARNING (ref)
4983 || TREE_CODE (up_bound) != INTEGER_CST
4984 /* Can not check flexible arrays. */
4985 || (TYPE_SIZE (TREE_TYPE (ref)) == NULL_TREE
4986 && TYPE_DOMAIN (TREE_TYPE (ref)) != NULL_TREE
4987 && TYPE_MAX_VALUE (TYPE_DOMAIN (TREE_TYPE (ref))) == NULL_TREE)
4988 /* Accesses after the end of arrays of size 0 (gcc
4989 extension) and 1 are likely intentional ("struct
4991 || compare_tree_int (up_bound, 1) <= 0)
4994 low_bound = array_ref_low_bound (ref);
4996 if (TREE_CODE (low_sub) == SSA_NAME)
4998 vr = get_value_range (low_sub);
4999 if (vr->type == VR_RANGE || vr->type == VR_ANTI_RANGE)
5001 low_sub = vr->type == VR_RANGE ? vr->max : vr->min;
5002 up_sub = vr->type == VR_RANGE ? vr->min : vr->max;
5006 if (vr && vr->type == VR_ANTI_RANGE)
5008 if (TREE_CODE (up_sub) == INTEGER_CST
5009 && tree_int_cst_lt (up_bound, up_sub)
5010 && TREE_CODE (low_sub) == INTEGER_CST
5011 && tree_int_cst_lt (low_sub, low_bound))
5013 warning_at (location, OPT_Warray_bounds,
5014 "array subscript is outside array bounds");
5015 TREE_NO_WARNING (ref) = 1;
5018 else if (TREE_CODE (up_sub) == INTEGER_CST
5019 && tree_int_cst_lt (up_bound, up_sub)
5020 && !tree_int_cst_equal (up_bound, up_sub)
5021 && (!ignore_off_by_one
5022 || !tree_int_cst_equal (int_const_binop (PLUS_EXPR,
5028 warning_at (location, OPT_Warray_bounds,
5029 "array subscript is above array bounds");
5030 TREE_NO_WARNING (ref) = 1;
5032 else if (TREE_CODE (low_sub) == INTEGER_CST
5033 && tree_int_cst_lt (low_sub, low_bound))
5035 warning_at (location, OPT_Warray_bounds,
5036 "array subscript is below array bounds");
5037 TREE_NO_WARNING (ref) = 1;
5041 /* Searches if the expr T, located at LOCATION computes
5042 address of an ARRAY_REF, and call check_array_ref on it. */
5045 search_for_addr_array (tree t, location_t location)
5047 while (TREE_CODE (t) == SSA_NAME)
5049 gimple g = SSA_NAME_DEF_STMT (t);
5051 if (gimple_code (g) != GIMPLE_ASSIGN)
5054 if (get_gimple_rhs_class (gimple_assign_rhs_code (g))
5055 != GIMPLE_SINGLE_RHS)
5058 t = gimple_assign_rhs1 (g);
5062 /* We are only interested in addresses of ARRAY_REF's. */
5063 if (TREE_CODE (t) != ADDR_EXPR)
5066 /* Check each ARRAY_REFs in the reference chain. */
5069 if (TREE_CODE (t) == ARRAY_REF)
5070 check_array_ref (t, location, true /*ignore_off_by_one*/);
5072 t = TREE_OPERAND (t, 0);
5074 while (handled_component_p (t));
5077 /* walk_tree() callback that checks if *TP is
5078 an ARRAY_REF inside an ADDR_EXPR (in which an array
5079 subscript one outside the valid range is allowed). Call
5080 check_array_ref for each ARRAY_REF found. The location is
5084 check_array_bounds (tree *tp, int *walk_subtree, void *data)
5087 struct walk_stmt_info *wi = (struct walk_stmt_info *) data;
5088 const location_t *location = (const location_t *) wi->info;
5090 *walk_subtree = TRUE;
5092 if (TREE_CODE (t) == ARRAY_REF)
5093 check_array_ref (t, *location, false /*ignore_off_by_one*/);
5095 if (TREE_CODE (t) == INDIRECT_REF
5096 || (TREE_CODE (t) == RETURN_EXPR && TREE_OPERAND (t, 0)))
5097 search_for_addr_array (TREE_OPERAND (t, 0), *location);
5099 if (TREE_CODE (t) == ADDR_EXPR)
5100 *walk_subtree = FALSE;
5105 /* Walk over all statements of all reachable BBs and call check_array_bounds
5109 check_all_array_refs (void)
5112 gimple_stmt_iterator si;
5116 /* Skip bb's that are clearly unreachable. */
5117 if (single_pred_p (bb))
5120 bool reachable = true;
5122 edge e = EDGE_PRED (bb, 0);
5123 basic_block pred_bb = e->src;
5126 for (i = 0; VEC_iterate (edge, to_remove_edges, i, e2); ++i)
5136 if (!gsi_end_p (gsi_last_bb (pred_bb)))
5137 ls = gsi_stmt (gsi_last_bb (pred_bb));
5139 if (ls && gimple_code (ls) == GIMPLE_COND
5140 && ((gimple_cond_false_p (ls)
5141 && (EDGE_PRED (bb, 0)->flags & EDGE_TRUE_VALUE))
5142 || (gimple_cond_true_p (ls)
5143 && (EDGE_PRED (bb, 0)->flags & EDGE_FALSE_VALUE))))
5146 for (si = gsi_start_bb (bb); !gsi_end_p (si); gsi_next (&si))
5148 gimple stmt = gsi_stmt (si);
5149 struct walk_stmt_info wi;
5150 if (!gimple_has_location (stmt))
5153 if (is_gimple_call (stmt))
5156 size_t n = gimple_call_num_args (stmt);
5157 for (i = 0; i < n; i++)
5159 tree arg = gimple_call_arg (stmt, i);
5160 search_for_addr_array (arg, gimple_location (stmt));
5165 memset (&wi, 0, sizeof (wi));
5166 wi.info = CONST_CAST (void *, (const void *)
5167 gimple_location_ptr (stmt));
5169 walk_gimple_op (gsi_stmt (si),
5177 /* Convert range assertion expressions into the implied copies and
5178 copy propagate away the copies. Doing the trivial copy propagation
5179 here avoids the need to run the full copy propagation pass after
5182 FIXME, this will eventually lead to copy propagation removing the
5183 names that had useful range information attached to them. For
5184 instance, if we had the assertion N_i = ASSERT_EXPR <N_j, N_j > 3>,
5185 then N_i will have the range [3, +INF].
5187 However, by converting the assertion into the implied copy
5188 operation N_i = N_j, we will then copy-propagate N_j into the uses
5189 of N_i and lose the range information. We may want to hold on to
5190 ASSERT_EXPRs a little while longer as the ranges could be used in
5191 things like jump threading.
5193 The problem with keeping ASSERT_EXPRs around is that passes after
5194 VRP need to handle them appropriately.
5196 Another approach would be to make the range information a first
5197 class property of the SSA_NAME so that it can be queried from
5198 any pass. This is made somewhat more complex by the need for
5199 multiple ranges to be associated with one SSA_NAME. */
5202 remove_range_assertions (void)
5205 gimple_stmt_iterator si;
5207 /* Note that the BSI iterator bump happens at the bottom of the
5208 loop and no bump is necessary if we're removing the statement
5209 referenced by the current BSI. */
5211 for (si = gsi_start_bb (bb); !gsi_end_p (si);)
5213 gimple stmt = gsi_stmt (si);
5216 if (is_gimple_assign (stmt)
5217 && gimple_assign_rhs_code (stmt) == ASSERT_EXPR)
5219 tree rhs = gimple_assign_rhs1 (stmt);
5221 tree cond = fold (ASSERT_EXPR_COND (rhs));
5222 use_operand_p use_p;
5223 imm_use_iterator iter;
5225 gcc_assert (cond != boolean_false_node);
5227 /* Propagate the RHS into every use of the LHS. */
5228 var = ASSERT_EXPR_VAR (rhs);
5229 FOR_EACH_IMM_USE_STMT (use_stmt, iter,
5230 gimple_assign_lhs (stmt))
5231 FOR_EACH_IMM_USE_ON_STMT (use_p, iter)
5233 SET_USE (use_p, var);
5234 gcc_assert (TREE_CODE (var) == SSA_NAME);
5237 /* And finally, remove the copy, it is not needed. */
5238 gsi_remove (&si, true);
5239 release_defs (stmt);
5247 /* Return true if STMT is interesting for VRP. */
5250 stmt_interesting_for_vrp (gimple stmt)
5252 if (gimple_code (stmt) == GIMPLE_PHI
5253 && is_gimple_reg (gimple_phi_result (stmt))
5254 && (INTEGRAL_TYPE_P (TREE_TYPE (gimple_phi_result (stmt)))
5255 || POINTER_TYPE_P (TREE_TYPE (gimple_phi_result (stmt)))))
5257 else if (is_gimple_assign (stmt) || is_gimple_call (stmt))
5259 tree lhs = gimple_get_lhs (stmt);
5261 /* In general, assignments with virtual operands are not useful
5262 for deriving ranges, with the obvious exception of calls to
5263 builtin functions. */
5264 if (lhs && TREE_CODE (lhs) == SSA_NAME
5265 && (INTEGRAL_TYPE_P (TREE_TYPE (lhs))
5266 || POINTER_TYPE_P (TREE_TYPE (lhs)))
5267 && ((is_gimple_call (stmt)
5268 && gimple_call_fndecl (stmt) != NULL_TREE
5269 && DECL_IS_BUILTIN (gimple_call_fndecl (stmt)))
5270 || !gimple_vuse (stmt)))
5273 else if (gimple_code (stmt) == GIMPLE_COND
5274 || gimple_code (stmt) == GIMPLE_SWITCH)
5281 /* Initialize local data structures for VRP. */
5284 vrp_initialize (void)
5288 vr_value = XCNEWVEC (value_range_t *, num_ssa_names);
5289 vr_phi_edge_counts = XCNEWVEC (int, num_ssa_names);
5293 gimple_stmt_iterator si;
5295 for (si = gsi_start_phis (bb); !gsi_end_p (si); gsi_next (&si))
5297 gimple phi = gsi_stmt (si);
5298 if (!stmt_interesting_for_vrp (phi))
5300 tree lhs = PHI_RESULT (phi);
5301 set_value_range_to_varying (get_value_range (lhs));
5302 prop_set_simulate_again (phi, false);
5305 prop_set_simulate_again (phi, true);
5308 for (si = gsi_start_bb (bb); !gsi_end_p (si); gsi_next (&si))
5310 gimple stmt = gsi_stmt (si);
5312 if (!stmt_interesting_for_vrp (stmt))
5316 FOR_EACH_SSA_TREE_OPERAND (def, stmt, i, SSA_OP_DEF)
5317 set_value_range_to_varying (get_value_range (def));
5318 prop_set_simulate_again (stmt, false);
5322 prop_set_simulate_again (stmt, true);
5329 /* Visit assignment STMT. If it produces an interesting range, record
5330 the SSA name in *OUTPUT_P. */
5332 static enum ssa_prop_result
5333 vrp_visit_assignment_or_call (gimple stmt, tree *output_p)
5337 enum gimple_code code = gimple_code (stmt);
5338 lhs = gimple_get_lhs (stmt);
5340 /* We only keep track of ranges in integral and pointer types. */
5341 if (TREE_CODE (lhs) == SSA_NAME
5342 && ((INTEGRAL_TYPE_P (TREE_TYPE (lhs))
5343 /* It is valid to have NULL MIN/MAX values on a type. See
5344 build_range_type. */
5345 && TYPE_MIN_VALUE (TREE_TYPE (lhs))
5346 && TYPE_MAX_VALUE (TREE_TYPE (lhs)))
5347 || POINTER_TYPE_P (TREE_TYPE (lhs))))
5350 value_range_t new_vr = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
5352 if (code == GIMPLE_CALL)
5353 extract_range_basic (&new_vr, stmt);
5355 extract_range_from_assignment (&new_vr, stmt);
5357 /* If STMT is inside a loop, we may be able to know something
5358 else about the range of LHS by examining scalar evolution
5360 if (current_loops && (l = loop_containing_stmt (stmt)))
5361 adjust_range_with_scev (&new_vr, l, stmt, lhs);
5363 if (update_value_range (lhs, &new_vr))
5367 if (dump_file && (dump_flags & TDF_DETAILS))
5369 fprintf (dump_file, "Found new range for ");
5370 print_generic_expr (dump_file, lhs, 0);
5371 fprintf (dump_file, ": ");
5372 dump_value_range (dump_file, &new_vr);
5373 fprintf (dump_file, "\n\n");
5376 if (new_vr.type == VR_VARYING)
5377 return SSA_PROP_VARYING;
5379 return SSA_PROP_INTERESTING;
5382 return SSA_PROP_NOT_INTERESTING;
5385 /* Every other statement produces no useful ranges. */
5386 FOR_EACH_SSA_TREE_OPERAND (def, stmt, iter, SSA_OP_DEF)
5387 set_value_range_to_varying (get_value_range (def));
5389 return SSA_PROP_VARYING;
5392 /* Helper that gets the value range of the SSA_NAME with version I
5393 or a symbolic range containing the SSA_NAME only if the value range
5394 is varying or undefined. */
5396 static inline value_range_t
5397 get_vr_for_comparison (int i)
5399 value_range_t vr = *(vr_value[i]);
5401 /* If name N_i does not have a valid range, use N_i as its own
5402 range. This allows us to compare against names that may
5403 have N_i in their ranges. */
5404 if (vr.type == VR_VARYING || vr.type == VR_UNDEFINED)
5407 vr.min = ssa_name (i);
5408 vr.max = ssa_name (i);
5414 /* Compare all the value ranges for names equivalent to VAR with VAL
5415 using comparison code COMP. Return the same value returned by
5416 compare_range_with_value, including the setting of
5417 *STRICT_OVERFLOW_P. */
5420 compare_name_with_value (enum tree_code comp, tree var, tree val,
5421 bool *strict_overflow_p)
5427 int used_strict_overflow;
5429 value_range_t equiv_vr;
5431 /* Get the set of equivalences for VAR. */
5432 e = get_value_range (var)->equiv;
5434 /* Start at -1. Set it to 0 if we do a comparison without relying
5435 on overflow, or 1 if all comparisons rely on overflow. */
5436 used_strict_overflow = -1;
5438 /* Compare vars' value range with val. */
5439 equiv_vr = get_vr_for_comparison (SSA_NAME_VERSION (var));
5441 retval = compare_range_with_value (comp, &equiv_vr, val, &sop);
5443 used_strict_overflow = sop ? 1 : 0;
5445 /* If the equiv set is empty we have done all work we need to do. */
5449 && used_strict_overflow > 0)
5450 *strict_overflow_p = true;
5454 EXECUTE_IF_SET_IN_BITMAP (e, 0, i, bi)
5456 equiv_vr = get_vr_for_comparison (i);
5458 t = compare_range_with_value (comp, &equiv_vr, val, &sop);
5461 /* If we get different answers from different members
5462 of the equivalence set this check must be in a dead
5463 code region. Folding it to a trap representation
5464 would be correct here. For now just return don't-know. */
5474 used_strict_overflow = 0;
5475 else if (used_strict_overflow < 0)
5476 used_strict_overflow = 1;
5481 && used_strict_overflow > 0)
5482 *strict_overflow_p = true;
5488 /* Given a comparison code COMP and names N1 and N2, compare all the
5489 ranges equivalent to N1 against all the ranges equivalent to N2
5490 to determine the value of N1 COMP N2. Return the same value
5491 returned by compare_ranges. Set *STRICT_OVERFLOW_P to indicate
5492 whether we relied on an overflow infinity in the comparison. */
5496 compare_names (enum tree_code comp, tree n1, tree n2,
5497 bool *strict_overflow_p)
5501 bitmap_iterator bi1, bi2;
5503 int used_strict_overflow;
5504 static bitmap_obstack *s_obstack = NULL;
5505 static bitmap s_e1 = NULL, s_e2 = NULL;
5507 /* Compare the ranges of every name equivalent to N1 against the
5508 ranges of every name equivalent to N2. */
5509 e1 = get_value_range (n1)->equiv;
5510 e2 = get_value_range (n2)->equiv;
5512 /* Use the fake bitmaps if e1 or e2 are not available. */
5513 if (s_obstack == NULL)
5515 s_obstack = XNEW (bitmap_obstack);
5516 bitmap_obstack_initialize (s_obstack);
5517 s_e1 = BITMAP_ALLOC (s_obstack);
5518 s_e2 = BITMAP_ALLOC (s_obstack);
5525 /* Add N1 and N2 to their own set of equivalences to avoid
5526 duplicating the body of the loop just to check N1 and N2
5528 bitmap_set_bit (e1, SSA_NAME_VERSION (n1));
5529 bitmap_set_bit (e2, SSA_NAME_VERSION (n2));
5531 /* If the equivalence sets have a common intersection, then the two
5532 names can be compared without checking their ranges. */
5533 if (bitmap_intersect_p (e1, e2))
5535 bitmap_clear_bit (e1, SSA_NAME_VERSION (n1));
5536 bitmap_clear_bit (e2, SSA_NAME_VERSION (n2));
5538 return (comp == EQ_EXPR || comp == GE_EXPR || comp == LE_EXPR)
5540 : boolean_false_node;
5543 /* Start at -1. Set it to 0 if we do a comparison without relying
5544 on overflow, or 1 if all comparisons rely on overflow. */
5545 used_strict_overflow = -1;
5547 /* Otherwise, compare all the equivalent ranges. First, add N1 and
5548 N2 to their own set of equivalences to avoid duplicating the body
5549 of the loop just to check N1 and N2 ranges. */
5550 EXECUTE_IF_SET_IN_BITMAP (e1, 0, i1, bi1)
5552 value_range_t vr1 = get_vr_for_comparison (i1);
5554 t = retval = NULL_TREE;
5555 EXECUTE_IF_SET_IN_BITMAP (e2, 0, i2, bi2)
5559 value_range_t vr2 = get_vr_for_comparison (i2);
5561 t = compare_ranges (comp, &vr1, &vr2, &sop);
5564 /* If we get different answers from different members
5565 of the equivalence set this check must be in a dead
5566 code region. Folding it to a trap representation
5567 would be correct here. For now just return don't-know. */
5571 bitmap_clear_bit (e1, SSA_NAME_VERSION (n1));
5572 bitmap_clear_bit (e2, SSA_NAME_VERSION (n2));
5578 used_strict_overflow = 0;
5579 else if (used_strict_overflow < 0)
5580 used_strict_overflow = 1;
5586 bitmap_clear_bit (e1, SSA_NAME_VERSION (n1));
5587 bitmap_clear_bit (e2, SSA_NAME_VERSION (n2));
5588 if (used_strict_overflow > 0)
5589 *strict_overflow_p = true;
5594 /* None of the equivalent ranges are useful in computing this
5596 bitmap_clear_bit (e1, SSA_NAME_VERSION (n1));
5597 bitmap_clear_bit (e2, SSA_NAME_VERSION (n2));
5601 /* Helper function for vrp_evaluate_conditional_warnv. */
5604 vrp_evaluate_conditional_warnv_with_ops_using_ranges (enum tree_code code,
5606 bool * strict_overflow_p)
5608 value_range_t *vr0, *vr1;
5610 vr0 = (TREE_CODE (op0) == SSA_NAME) ? get_value_range (op0) : NULL;
5611 vr1 = (TREE_CODE (op1) == SSA_NAME) ? get_value_range (op1) : NULL;
5614 return compare_ranges (code, vr0, vr1, strict_overflow_p);
5615 else if (vr0 && vr1 == NULL)
5616 return compare_range_with_value (code, vr0, op1, strict_overflow_p);
5617 else if (vr0 == NULL && vr1)
5618 return (compare_range_with_value
5619 (swap_tree_comparison (code), vr1, op0, strict_overflow_p));
5623 /* Helper function for vrp_evaluate_conditional_warnv. */
5626 vrp_evaluate_conditional_warnv_with_ops (enum tree_code code, tree op0,
5627 tree op1, bool use_equiv_p,
5628 bool *strict_overflow_p, bool *only_ranges)
5632 *only_ranges = true;
5634 /* We only deal with integral and pointer types. */
5635 if (!INTEGRAL_TYPE_P (TREE_TYPE (op0))
5636 && !POINTER_TYPE_P (TREE_TYPE (op0)))
5642 && (ret = vrp_evaluate_conditional_warnv_with_ops_using_ranges
5643 (code, op0, op1, strict_overflow_p)))
5645 *only_ranges = false;
5646 if (TREE_CODE (op0) == SSA_NAME && TREE_CODE (op1) == SSA_NAME)
5647 return compare_names (code, op0, op1, strict_overflow_p);
5648 else if (TREE_CODE (op0) == SSA_NAME)
5649 return compare_name_with_value (code, op0, op1, strict_overflow_p);
5650 else if (TREE_CODE (op1) == SSA_NAME)
5651 return (compare_name_with_value
5652 (swap_tree_comparison (code), op1, op0, strict_overflow_p));
5655 return vrp_evaluate_conditional_warnv_with_ops_using_ranges (code, op0, op1,
5660 /* Given (CODE OP0 OP1) within STMT, try to simplify it based on value range
5661 information. Return NULL if the conditional can not be evaluated.
5662 The ranges of all the names equivalent with the operands in COND
5663 will be used when trying to compute the value. If the result is
5664 based on undefined signed overflow, issue a warning if
5668 vrp_evaluate_conditional (enum tree_code code, tree op0, tree op1, gimple stmt)
5675 ret = vrp_evaluate_conditional_warnv_with_ops (code, op0, op1, true, &sop,
5680 enum warn_strict_overflow_code wc;
5681 const char* warnmsg;
5683 if (is_gimple_min_invariant (ret))
5685 wc = WARN_STRICT_OVERFLOW_CONDITIONAL;
5686 warnmsg = G_("assuming signed overflow does not occur when "
5687 "simplifying conditional to constant");
5691 wc = WARN_STRICT_OVERFLOW_COMPARISON;
5692 warnmsg = G_("assuming signed overflow does not occur when "
5693 "simplifying conditional");
5696 if (issue_strict_overflow_warning (wc))
5698 location_t location;
5700 if (!gimple_has_location (stmt))
5701 location = input_location;
5703 location = gimple_location (stmt);
5704 warning (OPT_Wstrict_overflow, "%H%s", &location, warnmsg);
5708 if (warn_type_limits
5709 && ret && only_ranges
5710 && TREE_CODE_CLASS (code) == tcc_comparison
5711 && TREE_CODE (op0) == SSA_NAME)
5713 /* If the comparison is being folded and the operand on the LHS
5714 is being compared against a constant value that is outside of
5715 the natural range of OP0's type, then the predicate will
5716 always fold regardless of the value of OP0. If -Wtype-limits
5717 was specified, emit a warning. */
5718 const char *warnmsg = NULL;
5719 tree type = TREE_TYPE (op0);
5720 value_range_t *vr0 = get_value_range (op0);
5722 if (vr0->type != VR_VARYING
5723 && INTEGRAL_TYPE_P (type)
5724 && vrp_val_is_min (vr0->min)
5725 && vrp_val_is_max (vr0->max)
5726 && is_gimple_min_invariant (op1))
5728 if (integer_zerop (ret))
5729 warnmsg = G_("comparison always false due to limited range of "
5732 warnmsg = G_("comparison always true due to limited range of "
5738 location_t location;
5740 if (!gimple_has_location (stmt))
5741 location = input_location;
5743 location = gimple_location (stmt);
5745 warning (OPT_Wtype_limits, "%H%s", &location, warnmsg);
5753 /* Visit conditional statement STMT. If we can determine which edge
5754 will be taken out of STMT's basic block, record it in
5755 *TAKEN_EDGE_P and return SSA_PROP_INTERESTING. Otherwise, return
5756 SSA_PROP_VARYING. */
5758 static enum ssa_prop_result
5759 vrp_visit_cond_stmt (gimple stmt, edge *taken_edge_p)
5764 *taken_edge_p = NULL;
5766 if (dump_file && (dump_flags & TDF_DETAILS))
5771 fprintf (dump_file, "\nVisiting conditional with predicate: ");
5772 print_gimple_stmt (dump_file, stmt, 0, 0);
5773 fprintf (dump_file, "\nWith known ranges\n");
5775 FOR_EACH_SSA_TREE_OPERAND (use, stmt, i, SSA_OP_USE)
5777 fprintf (dump_file, "\t");
5778 print_generic_expr (dump_file, use, 0);
5779 fprintf (dump_file, ": ");
5780 dump_value_range (dump_file, vr_value[SSA_NAME_VERSION (use)]);
5783 fprintf (dump_file, "\n");
5786 /* Compute the value of the predicate COND by checking the known
5787 ranges of each of its operands.
5789 Note that we cannot evaluate all the equivalent ranges here
5790 because those ranges may not yet be final and with the current
5791 propagation strategy, we cannot determine when the value ranges
5792 of the names in the equivalence set have changed.
5794 For instance, given the following code fragment
5798 i_14 = ASSERT_EXPR <i_5, i_5 != 0>
5802 Assume that on the first visit to i_14, i_5 has the temporary
5803 range [8, 8] because the second argument to the PHI function is
5804 not yet executable. We derive the range ~[0, 0] for i_14 and the
5805 equivalence set { i_5 }. So, when we visit 'if (i_14 == 1)' for
5806 the first time, since i_14 is equivalent to the range [8, 8], we
5807 determine that the predicate is always false.
5809 On the next round of propagation, i_13 is determined to be
5810 VARYING, which causes i_5 to drop down to VARYING. So, another
5811 visit to i_14 is scheduled. In this second visit, we compute the
5812 exact same range and equivalence set for i_14, namely ~[0, 0] and
5813 { i_5 }. But we did not have the previous range for i_5
5814 registered, so vrp_visit_assignment thinks that the range for
5815 i_14 has not changed. Therefore, the predicate 'if (i_14 == 1)'
5816 is not visited again, which stops propagation from visiting
5817 statements in the THEN clause of that if().
5819 To properly fix this we would need to keep the previous range
5820 value for the names in the equivalence set. This way we would've
5821 discovered that from one visit to the other i_5 changed from
5822 range [8, 8] to VR_VARYING.
5824 However, fixing this apparent limitation may not be worth the
5825 additional checking. Testing on several code bases (GCC, DLV,
5826 MICO, TRAMP3D and SPEC2000) showed that doing this results in
5827 4 more predicates folded in SPEC. */
5830 val = vrp_evaluate_conditional_warnv_with_ops (gimple_cond_code (stmt),
5831 gimple_cond_lhs (stmt),
5832 gimple_cond_rhs (stmt),
5837 *taken_edge_p = find_taken_edge (gimple_bb (stmt), val);
5840 if (dump_file && (dump_flags & TDF_DETAILS))
5842 "\nIgnoring predicate evaluation because "
5843 "it assumes that signed overflow is undefined");
5848 if (dump_file && (dump_flags & TDF_DETAILS))
5850 fprintf (dump_file, "\nPredicate evaluates to: ");
5851 if (val == NULL_TREE)
5852 fprintf (dump_file, "DON'T KNOW\n");
5854 print_generic_stmt (dump_file, val, 0);
5857 return (*taken_edge_p) ? SSA_PROP_INTERESTING : SSA_PROP_VARYING;
5860 /* Searches the case label vector VEC for the index *IDX of the CASE_LABEL
5861 that includes the value VAL. The search is restricted to the range
5862 [START_IDX, n - 1] where n is the size of VEC.
5864 If there is a CASE_LABEL for VAL, its index is placed in IDX and true is
5867 If there is no CASE_LABEL for VAL and there is one that is larger than VAL,
5868 it is placed in IDX and false is returned.
5870 If VAL is larger than any CASE_LABEL, n is placed on IDX and false is
5874 find_case_label_index (gimple stmt, size_t start_idx, tree val, size_t *idx)
5876 size_t n = gimple_switch_num_labels (stmt);
5879 /* Find case label for minimum of the value range or the next one.
5880 At each iteration we are searching in [low, high - 1]. */
5882 for (low = start_idx, high = n; high != low; )
5886 /* Note that i != high, so we never ask for n. */
5887 size_t i = (high + low) / 2;
5888 t = gimple_switch_label (stmt, i);
5890 /* Cache the result of comparing CASE_LOW and val. */
5891 cmp = tree_int_cst_compare (CASE_LOW (t), val);
5895 /* Ranges cannot be empty. */
5904 if (CASE_HIGH (t) != NULL
5905 && tree_int_cst_compare (CASE_HIGH (t), val) >= 0)
5917 /* Searches the case label vector VEC for the range of CASE_LABELs that is used
5918 for values between MIN and MAX. The first index is placed in MIN_IDX. The
5919 last index is placed in MAX_IDX. If the range of CASE_LABELs is empty
5920 then MAX_IDX < MIN_IDX.
5921 Returns true if the default label is not needed. */
5924 find_case_label_range (gimple stmt, tree min, tree max, size_t *min_idx,
5928 bool min_take_default = !find_case_label_index (stmt, 1, min, &i);
5929 bool max_take_default = !find_case_label_index (stmt, i, max, &j);
5933 && max_take_default)
5935 /* Only the default case label reached.
5936 Return an empty range. */
5943 bool take_default = min_take_default || max_take_default;
5947 if (max_take_default)
5950 /* If the case label range is continuous, we do not need
5951 the default case label. Verify that. */
5952 high = CASE_LOW (gimple_switch_label (stmt, i));
5953 if (CASE_HIGH (gimple_switch_label (stmt, i)))
5954 high = CASE_HIGH (gimple_switch_label (stmt, i));
5955 for (k = i + 1; k <= j; ++k)
5957 low = CASE_LOW (gimple_switch_label (stmt, k));
5958 if (!integer_onep (int_const_binop (MINUS_EXPR, low, high, 0)))
5960 take_default = true;
5964 if (CASE_HIGH (gimple_switch_label (stmt, k)))
5965 high = CASE_HIGH (gimple_switch_label (stmt, k));
5970 return !take_default;
5974 /* Visit switch statement STMT. If we can determine which edge
5975 will be taken out of STMT's basic block, record it in
5976 *TAKEN_EDGE_P and return SSA_PROP_INTERESTING. Otherwise, return
5977 SSA_PROP_VARYING. */
5979 static enum ssa_prop_result
5980 vrp_visit_switch_stmt (gimple stmt, edge *taken_edge_p)
5984 size_t i = 0, j = 0, n;
5987 *taken_edge_p = NULL;
5988 op = gimple_switch_index (stmt);
5989 if (TREE_CODE (op) != SSA_NAME)
5990 return SSA_PROP_VARYING;
5992 vr = get_value_range (op);
5993 if (dump_file && (dump_flags & TDF_DETAILS))
5995 fprintf (dump_file, "\nVisiting switch expression with operand ");
5996 print_generic_expr (dump_file, op, 0);
5997 fprintf (dump_file, " with known range ");
5998 dump_value_range (dump_file, vr);
5999 fprintf (dump_file, "\n");
6002 if (vr->type != VR_RANGE
6003 || symbolic_range_p (vr))
6004 return SSA_PROP_VARYING;
6006 /* Find the single edge that is taken from the switch expression. */
6007 n = gimple_switch_num_labels (stmt);
6009 take_default = !find_case_label_range (stmt, vr->min, vr->max, &i, &j);
6011 /* Check if the range spans no CASE_LABEL. If so, we only reach the default
6015 gcc_assert (take_default);
6016 val = gimple_switch_default_label (stmt);
6020 /* Check if labels with index i to j and maybe the default label
6021 are all reaching the same label. */
6023 val = gimple_switch_label (stmt, i);
6025 && CASE_LABEL (gimple_switch_default_label (stmt))
6026 != CASE_LABEL (val))
6028 if (dump_file && (dump_flags & TDF_DETAILS))
6029 fprintf (dump_file, " not a single destination for this "
6031 return SSA_PROP_VARYING;
6033 for (++i; i <= j; ++i)
6035 if (CASE_LABEL (gimple_switch_label (stmt, i)) != CASE_LABEL (val))
6037 if (dump_file && (dump_flags & TDF_DETAILS))
6038 fprintf (dump_file, " not a single destination for this "
6040 return SSA_PROP_VARYING;
6045 *taken_edge_p = find_edge (gimple_bb (stmt),
6046 label_to_block (CASE_LABEL (val)));
6048 if (dump_file && (dump_flags & TDF_DETAILS))
6050 fprintf (dump_file, " will take edge to ");
6051 print_generic_stmt (dump_file, CASE_LABEL (val), 0);
6054 return SSA_PROP_INTERESTING;
6058 /* Evaluate statement STMT. If the statement produces a useful range,
6059 return SSA_PROP_INTERESTING and record the SSA name with the
6060 interesting range into *OUTPUT_P.
6062 If STMT is a conditional branch and we can determine its truth
6063 value, the taken edge is recorded in *TAKEN_EDGE_P.
6065 If STMT produces a varying value, return SSA_PROP_VARYING. */
6067 static enum ssa_prop_result
6068 vrp_visit_stmt (gimple stmt, edge *taken_edge_p, tree *output_p)
6073 if (dump_file && (dump_flags & TDF_DETAILS))
6075 fprintf (dump_file, "\nVisiting statement:\n");
6076 print_gimple_stmt (dump_file, stmt, 0, dump_flags);
6077 fprintf (dump_file, "\n");
6080 if (is_gimple_assign (stmt) || is_gimple_call (stmt))
6082 /* In general, assignments with virtual operands are not useful
6083 for deriving ranges, with the obvious exception of calls to
6084 builtin functions. */
6086 if ((is_gimple_call (stmt)
6087 && gimple_call_fndecl (stmt) != NULL_TREE
6088 && DECL_IS_BUILTIN (gimple_call_fndecl (stmt)))
6089 || !gimple_vuse (stmt))
6090 return vrp_visit_assignment_or_call (stmt, output_p);
6092 else if (gimple_code (stmt) == GIMPLE_COND)
6093 return vrp_visit_cond_stmt (stmt, taken_edge_p);
6094 else if (gimple_code (stmt) == GIMPLE_SWITCH)
6095 return vrp_visit_switch_stmt (stmt, taken_edge_p);
6097 /* All other statements produce nothing of interest for VRP, so mark
6098 their outputs varying and prevent further simulation. */
6099 FOR_EACH_SSA_TREE_OPERAND (def, stmt, iter, SSA_OP_DEF)
6100 set_value_range_to_varying (get_value_range (def));
6102 return SSA_PROP_VARYING;
6106 /* Meet operation for value ranges. Given two value ranges VR0 and
6107 VR1, store in VR0 a range that contains both VR0 and VR1. This
6108 may not be the smallest possible such range. */
6111 vrp_meet (value_range_t *vr0, value_range_t *vr1)
6113 if (vr0->type == VR_UNDEFINED)
6115 copy_value_range (vr0, vr1);
6119 if (vr1->type == VR_UNDEFINED)
6121 /* Nothing to do. VR0 already has the resulting range. */
6125 if (vr0->type == VR_VARYING)
6127 /* Nothing to do. VR0 already has the resulting range. */
6131 if (vr1->type == VR_VARYING)
6133 set_value_range_to_varying (vr0);
6137 if (vr0->type == VR_RANGE && vr1->type == VR_RANGE)
6142 /* Compute the convex hull of the ranges. The lower limit of
6143 the new range is the minimum of the two ranges. If they
6144 cannot be compared, then give up. */
6145 cmp = compare_values (vr0->min, vr1->min);
6146 if (cmp == 0 || cmp == 1)
6153 /* Similarly, the upper limit of the new range is the maximum
6154 of the two ranges. If they cannot be compared, then
6156 cmp = compare_values (vr0->max, vr1->max);
6157 if (cmp == 0 || cmp == -1)
6164 /* Check for useless ranges. */
6165 if (INTEGRAL_TYPE_P (TREE_TYPE (min))
6166 && ((vrp_val_is_min (min) || is_overflow_infinity (min))
6167 && (vrp_val_is_max (max) || is_overflow_infinity (max))))
6170 /* The resulting set of equivalences is the intersection of
6172 if (vr0->equiv && vr1->equiv && vr0->equiv != vr1->equiv)
6173 bitmap_and_into (vr0->equiv, vr1->equiv);
6174 else if (vr0->equiv && !vr1->equiv)
6175 bitmap_clear (vr0->equiv);
6177 set_value_range (vr0, vr0->type, min, max, vr0->equiv);
6179 else if (vr0->type == VR_ANTI_RANGE && vr1->type == VR_ANTI_RANGE)
6181 /* Two anti-ranges meet only if their complements intersect.
6182 Only handle the case of identical ranges. */
6183 if (compare_values (vr0->min, vr1->min) == 0
6184 && compare_values (vr0->max, vr1->max) == 0
6185 && compare_values (vr0->min, vr0->max) == 0)
6187 /* The resulting set of equivalences is the intersection of
6189 if (vr0->equiv && vr1->equiv && vr0->equiv != vr1->equiv)
6190 bitmap_and_into (vr0->equiv, vr1->equiv);
6191 else if (vr0->equiv && !vr1->equiv)
6192 bitmap_clear (vr0->equiv);
6197 else if (vr0->type == VR_ANTI_RANGE || vr1->type == VR_ANTI_RANGE)
6199 /* For a numeric range [VAL1, VAL2] and an anti-range ~[VAL3, VAL4],
6200 only handle the case where the ranges have an empty intersection.
6201 The result of the meet operation is the anti-range. */
6202 if (!symbolic_range_p (vr0)
6203 && !symbolic_range_p (vr1)
6204 && !value_ranges_intersect_p (vr0, vr1))
6206 /* Copy most of VR1 into VR0. Don't copy VR1's equivalence
6207 set. We need to compute the intersection of the two
6208 equivalence sets. */
6209 if (vr1->type == VR_ANTI_RANGE)
6210 set_value_range (vr0, vr1->type, vr1->min, vr1->max, vr0->equiv);
6212 /* The resulting set of equivalences is the intersection of
6214 if (vr0->equiv && vr1->equiv && vr0->equiv != vr1->equiv)
6215 bitmap_and_into (vr0->equiv, vr1->equiv);
6216 else if (vr0->equiv && !vr1->equiv)
6217 bitmap_clear (vr0->equiv);
6228 /* Failed to find an efficient meet. Before giving up and setting
6229 the result to VARYING, see if we can at least derive a useful
6230 anti-range. FIXME, all this nonsense about distinguishing
6231 anti-ranges from ranges is necessary because of the odd
6232 semantics of range_includes_zero_p and friends. */
6233 if (!symbolic_range_p (vr0)
6234 && ((vr0->type == VR_RANGE && !range_includes_zero_p (vr0))
6235 || (vr0->type == VR_ANTI_RANGE && range_includes_zero_p (vr0)))
6236 && !symbolic_range_p (vr1)
6237 && ((vr1->type == VR_RANGE && !range_includes_zero_p (vr1))
6238 || (vr1->type == VR_ANTI_RANGE && range_includes_zero_p (vr1))))
6240 set_value_range_to_nonnull (vr0, TREE_TYPE (vr0->min));
6242 /* Since this meet operation did not result from the meeting of
6243 two equivalent names, VR0 cannot have any equivalences. */
6245 bitmap_clear (vr0->equiv);
6248 set_value_range_to_varying (vr0);
6252 /* Visit all arguments for PHI node PHI that flow through executable
6253 edges. If a valid value range can be derived from all the incoming
6254 value ranges, set a new range for the LHS of PHI. */
6256 static enum ssa_prop_result
6257 vrp_visit_phi_node (gimple phi)
6260 tree lhs = PHI_RESULT (phi);
6261 value_range_t *lhs_vr = get_value_range (lhs);
6262 value_range_t vr_result = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
6263 int edges, old_edges;
6265 copy_value_range (&vr_result, lhs_vr);
6267 if (dump_file && (dump_flags & TDF_DETAILS))
6269 fprintf (dump_file, "\nVisiting PHI node: ");
6270 print_gimple_stmt (dump_file, phi, 0, dump_flags);
6274 for (i = 0; i < gimple_phi_num_args (phi); i++)
6276 edge e = gimple_phi_arg_edge (phi, i);
6278 if (dump_file && (dump_flags & TDF_DETAILS))
6281 "\n Argument #%d (%d -> %d %sexecutable)\n",
6282 (int) i, e->src->index, e->dest->index,
6283 (e->flags & EDGE_EXECUTABLE) ? "" : "not ");
6286 if (e->flags & EDGE_EXECUTABLE)
6288 tree arg = PHI_ARG_DEF (phi, i);
6289 value_range_t vr_arg;
6293 if (TREE_CODE (arg) == SSA_NAME)
6295 vr_arg = *(get_value_range (arg));
6299 if (is_overflow_infinity (arg))
6301 arg = copy_node (arg);
6302 TREE_OVERFLOW (arg) = 0;
6305 vr_arg.type = VR_RANGE;
6308 vr_arg.equiv = NULL;
6311 if (dump_file && (dump_flags & TDF_DETAILS))
6313 fprintf (dump_file, "\t");
6314 print_generic_expr (dump_file, arg, dump_flags);
6315 fprintf (dump_file, "\n\tValue: ");
6316 dump_value_range (dump_file, &vr_arg);
6317 fprintf (dump_file, "\n");
6320 vrp_meet (&vr_result, &vr_arg);
6322 if (vr_result.type == VR_VARYING)
6327 if (vr_result.type == VR_VARYING)
6330 old_edges = vr_phi_edge_counts[SSA_NAME_VERSION (lhs)];
6331 vr_phi_edge_counts[SSA_NAME_VERSION (lhs)] = edges;
6333 /* To prevent infinite iterations in the algorithm, derive ranges
6334 when the new value is slightly bigger or smaller than the
6335 previous one. We don't do this if we have seen a new executable
6336 edge; this helps us avoid an overflow infinity for conditionals
6337 which are not in a loop. */
6338 if (lhs_vr->type == VR_RANGE && vr_result.type == VR_RANGE
6339 && edges <= old_edges)
6341 if (!POINTER_TYPE_P (TREE_TYPE (lhs)))
6343 int cmp_min = compare_values (lhs_vr->min, vr_result.min);
6344 int cmp_max = compare_values (lhs_vr->max, vr_result.max);
6346 /* If the new minimum is smaller or larger than the previous
6347 one, go all the way to -INF. In the first case, to avoid
6348 iterating millions of times to reach -INF, and in the
6349 other case to avoid infinite bouncing between different
6351 if (cmp_min > 0 || cmp_min < 0)
6353 /* If we will end up with a (-INF, +INF) range, set it to
6354 VARYING. Same if the previous max value was invalid for
6355 the type and we'd end up with vr_result.min > vr_result.max. */
6356 if (vrp_val_is_max (vr_result.max)
6357 || compare_values (TYPE_MIN_VALUE (TREE_TYPE (vr_result.min)),
6361 if (!needs_overflow_infinity (TREE_TYPE (vr_result.min))
6362 || !vrp_var_may_overflow (lhs, phi))
6363 vr_result.min = TYPE_MIN_VALUE (TREE_TYPE (vr_result.min));
6364 else if (supports_overflow_infinity (TREE_TYPE (vr_result.min)))
6366 negative_overflow_infinity (TREE_TYPE (vr_result.min));
6371 /* Similarly, if the new maximum is smaller or larger than
6372 the previous one, go all the way to +INF. */
6373 if (cmp_max < 0 || cmp_max > 0)
6375 /* If we will end up with a (-INF, +INF) range, set it to
6376 VARYING. Same if the previous min value was invalid for
6377 the type and we'd end up with vr_result.max < vr_result.min. */
6378 if (vrp_val_is_min (vr_result.min)
6379 || compare_values (TYPE_MAX_VALUE (TREE_TYPE (vr_result.max)),
6383 if (!needs_overflow_infinity (TREE_TYPE (vr_result.max))
6384 || !vrp_var_may_overflow (lhs, phi))
6385 vr_result.max = TYPE_MAX_VALUE (TREE_TYPE (vr_result.max));
6386 else if (supports_overflow_infinity (TREE_TYPE (vr_result.max)))
6388 positive_overflow_infinity (TREE_TYPE (vr_result.max));
6395 /* If the new range is different than the previous value, keep
6397 if (update_value_range (lhs, &vr_result))
6398 return SSA_PROP_INTERESTING;
6400 /* Nothing changed, don't add outgoing edges. */
6401 return SSA_PROP_NOT_INTERESTING;
6403 /* No match found. Set the LHS to VARYING. */
6405 set_value_range_to_varying (lhs_vr);
6406 return SSA_PROP_VARYING;
6409 /* Simplify boolean operations if the source is known
6410 to be already a boolean. */
6412 simplify_truth_ops_using_ranges (gimple_stmt_iterator *gsi, gimple stmt)
6414 enum tree_code rhs_code = gimple_assign_rhs_code (stmt);
6419 bool need_conversion;
6421 op0 = gimple_assign_rhs1 (stmt);
6422 if (TYPE_PRECISION (TREE_TYPE (op0)) != 1)
6424 if (TREE_CODE (op0) != SSA_NAME)
6426 vr = get_value_range (op0);
6428 val = compare_range_with_value (GE_EXPR, vr, integer_zero_node, &sop);
6429 if (!val || !integer_onep (val))
6432 val = compare_range_with_value (LE_EXPR, vr, integer_one_node, &sop);
6433 if (!val || !integer_onep (val))
6437 if (rhs_code == TRUTH_NOT_EXPR)
6440 op1 = build_int_cst (TREE_TYPE (op0), 1);
6444 op1 = gimple_assign_rhs2 (stmt);
6446 /* Reduce number of cases to handle. */
6447 if (is_gimple_min_invariant (op1))
6449 /* Exclude anything that should have been already folded. */
6450 if (rhs_code != EQ_EXPR
6451 && rhs_code != NE_EXPR
6452 && rhs_code != TRUTH_XOR_EXPR)
6455 if (!integer_zerop (op1)
6456 && !integer_onep (op1)
6457 && !integer_all_onesp (op1))
6460 /* Limit the number of cases we have to consider. */
6461 if (rhs_code == EQ_EXPR)
6464 op1 = fold_unary (TRUTH_NOT_EXPR, TREE_TYPE (op1), op1);
6469 /* Punt on A == B as there is no BIT_XNOR_EXPR. */
6470 if (rhs_code == EQ_EXPR)
6473 if (TYPE_PRECISION (TREE_TYPE (op1)) != 1)
6475 vr = get_value_range (op1);
6476 val = compare_range_with_value (GE_EXPR, vr, integer_zero_node, &sop);
6477 if (!val || !integer_onep (val))
6480 val = compare_range_with_value (LE_EXPR, vr, integer_one_node, &sop);
6481 if (!val || !integer_onep (val))
6487 if (sop && issue_strict_overflow_warning (WARN_STRICT_OVERFLOW_MISC))
6489 location_t location;
6491 if (!gimple_has_location (stmt))
6492 location = input_location;
6494 location = gimple_location (stmt);
6496 if (rhs_code == TRUTH_AND_EXPR || rhs_code == TRUTH_OR_EXPR)
6497 warning_at (location, OPT_Wstrict_overflow,
6498 _("assuming signed overflow does not occur when "
6499 "simplifying && or || to & or |"));
6501 warning_at (location, OPT_Wstrict_overflow,
6502 _("assuming signed overflow does not occur when "
6503 "simplifying ==, != or ! to identity or ^"));
6507 !useless_type_conversion_p (TREE_TYPE (gimple_assign_lhs (stmt)),
6510 /* Make sure to not sign-extend -1 as a boolean value. */
6512 && !TYPE_UNSIGNED (TREE_TYPE (op0))
6513 && TYPE_PRECISION (TREE_TYPE (op0)) == 1)
6518 case TRUTH_AND_EXPR:
6519 rhs_code = BIT_AND_EXPR;
6522 rhs_code = BIT_IOR_EXPR;
6524 case TRUTH_XOR_EXPR:
6526 if (integer_zerop (op1))
6528 gimple_assign_set_rhs_with_ops (gsi,
6529 need_conversion ? NOP_EXPR : SSA_NAME,
6531 update_stmt (gsi_stmt (*gsi));
6535 rhs_code = BIT_XOR_EXPR;
6541 if (need_conversion)
6544 gimple_assign_set_rhs_with_ops (gsi, rhs_code, op0, op1);
6545 update_stmt (gsi_stmt (*gsi));
6549 /* Simplify a division or modulo operator to a right shift or
6550 bitwise and if the first operand is unsigned or is greater
6551 than zero and the second operand is an exact power of two. */
6554 simplify_div_or_mod_using_ranges (gimple stmt)
6556 enum tree_code rhs_code = gimple_assign_rhs_code (stmt);
6558 tree op0 = gimple_assign_rhs1 (stmt);
6559 tree op1 = gimple_assign_rhs2 (stmt);
6560 value_range_t *vr = get_value_range (gimple_assign_rhs1 (stmt));
6562 if (TYPE_UNSIGNED (TREE_TYPE (op0)))
6564 val = integer_one_node;
6570 val = compare_range_with_value (GE_EXPR, vr, integer_zero_node, &sop);
6574 && integer_onep (val)
6575 && issue_strict_overflow_warning (WARN_STRICT_OVERFLOW_MISC))
6577 location_t location;
6579 if (!gimple_has_location (stmt))
6580 location = input_location;
6582 location = gimple_location (stmt);
6583 warning (OPT_Wstrict_overflow,
6584 ("%Hassuming signed overflow does not occur when "
6585 "simplifying / or %% to >> or &"),
6590 if (val && integer_onep (val))
6594 if (rhs_code == TRUNC_DIV_EXPR)
6596 t = build_int_cst (NULL_TREE, tree_log2 (op1));
6597 gimple_assign_set_rhs_code (stmt, RSHIFT_EXPR);
6598 gimple_assign_set_rhs1 (stmt, op0);
6599 gimple_assign_set_rhs2 (stmt, t);
6603 t = build_int_cst (TREE_TYPE (op1), 1);
6604 t = int_const_binop (MINUS_EXPR, op1, t, 0);
6605 t = fold_convert (TREE_TYPE (op0), t);
6607 gimple_assign_set_rhs_code (stmt, BIT_AND_EXPR);
6608 gimple_assign_set_rhs1 (stmt, op0);
6609 gimple_assign_set_rhs2 (stmt, t);
6619 /* If the operand to an ABS_EXPR is >= 0, then eliminate the
6620 ABS_EXPR. If the operand is <= 0, then simplify the
6621 ABS_EXPR into a NEGATE_EXPR. */
6624 simplify_abs_using_ranges (gimple stmt)
6627 tree op = gimple_assign_rhs1 (stmt);
6628 tree type = TREE_TYPE (op);
6629 value_range_t *vr = get_value_range (op);
6631 if (TYPE_UNSIGNED (type))
6633 val = integer_zero_node;
6639 val = compare_range_with_value (LE_EXPR, vr, integer_zero_node, &sop);
6643 val = compare_range_with_value (GE_EXPR, vr, integer_zero_node,
6648 if (integer_zerop (val))
6649 val = integer_one_node;
6650 else if (integer_onep (val))
6651 val = integer_zero_node;
6656 && (integer_onep (val) || integer_zerop (val)))
6658 if (sop && issue_strict_overflow_warning (WARN_STRICT_OVERFLOW_MISC))
6660 location_t location;
6662 if (!gimple_has_location (stmt))
6663 location = input_location;
6665 location = gimple_location (stmt);
6666 warning (OPT_Wstrict_overflow,
6667 ("%Hassuming signed overflow does not occur when "
6668 "simplifying abs (X) to X or -X"),
6672 gimple_assign_set_rhs1 (stmt, op);
6673 if (integer_onep (val))
6674 gimple_assign_set_rhs_code (stmt, NEGATE_EXPR);
6676 gimple_assign_set_rhs_code (stmt, SSA_NAME);
6685 /* We are comparing trees OP0 and OP1 using COND_CODE. OP0 has
6686 a known value range VR.
6688 If there is one and only one value which will satisfy the
6689 conditional, then return that value. Else return NULL. */
6692 test_for_singularity (enum tree_code cond_code, tree op0,
6693 tree op1, value_range_t *vr)
6698 /* Extract minimum/maximum values which satisfy the
6699 the conditional as it was written. */
6700 if (cond_code == LE_EXPR || cond_code == LT_EXPR)
6702 /* This should not be negative infinity; there is no overflow
6704 min = TYPE_MIN_VALUE (TREE_TYPE (op0));
6707 if (cond_code == LT_EXPR && !is_overflow_infinity (max))
6709 tree one = build_int_cst (TREE_TYPE (op0), 1);
6710 max = fold_build2 (MINUS_EXPR, TREE_TYPE (op0), max, one);
6712 TREE_NO_WARNING (max) = 1;
6715 else if (cond_code == GE_EXPR || cond_code == GT_EXPR)
6717 /* This should not be positive infinity; there is no overflow
6719 max = TYPE_MAX_VALUE (TREE_TYPE (op0));
6722 if (cond_code == GT_EXPR && !is_overflow_infinity (min))
6724 tree one = build_int_cst (TREE_TYPE (op0), 1);
6725 min = fold_build2 (PLUS_EXPR, TREE_TYPE (op0), min, one);
6727 TREE_NO_WARNING (min) = 1;
6731 /* Now refine the minimum and maximum values using any
6732 value range information we have for op0. */
6735 if (compare_values (vr->min, min) == -1)
6739 if (compare_values (vr->max, max) == 1)
6744 /* If the new min/max values have converged to a single value,
6745 then there is only one value which can satisfy the condition,
6746 return that value. */
6747 if (operand_equal_p (min, max, 0) && is_gimple_min_invariant (min))
6753 /* Simplify a conditional using a relational operator to an equality
6754 test if the range information indicates only one value can satisfy
6755 the original conditional. */
6758 simplify_cond_using_ranges (gimple stmt)
6760 tree op0 = gimple_cond_lhs (stmt);
6761 tree op1 = gimple_cond_rhs (stmt);
6762 enum tree_code cond_code = gimple_cond_code (stmt);
6764 if (cond_code != NE_EXPR
6765 && cond_code != EQ_EXPR
6766 && TREE_CODE (op0) == SSA_NAME
6767 && INTEGRAL_TYPE_P (TREE_TYPE (op0))
6768 && is_gimple_min_invariant (op1))
6770 value_range_t *vr = get_value_range (op0);
6772 /* If we have range information for OP0, then we might be
6773 able to simplify this conditional. */
6774 if (vr->type == VR_RANGE)
6776 tree new_tree = test_for_singularity (cond_code, op0, op1, vr);
6782 fprintf (dump_file, "Simplified relational ");
6783 print_gimple_stmt (dump_file, stmt, 0, 0);
6784 fprintf (dump_file, " into ");
6787 gimple_cond_set_code (stmt, EQ_EXPR);
6788 gimple_cond_set_lhs (stmt, op0);
6789 gimple_cond_set_rhs (stmt, new_tree);
6795 print_gimple_stmt (dump_file, stmt, 0, 0);
6796 fprintf (dump_file, "\n");
6802 /* Try again after inverting the condition. We only deal
6803 with integral types here, so no need to worry about
6804 issues with inverting FP comparisons. */
6805 cond_code = invert_tree_comparison (cond_code, false);
6806 new_tree = test_for_singularity (cond_code, op0, op1, vr);
6812 fprintf (dump_file, "Simplified relational ");
6813 print_gimple_stmt (dump_file, stmt, 0, 0);
6814 fprintf (dump_file, " into ");
6817 gimple_cond_set_code (stmt, NE_EXPR);
6818 gimple_cond_set_lhs (stmt, op0);
6819 gimple_cond_set_rhs (stmt, new_tree);
6825 print_gimple_stmt (dump_file, stmt, 0, 0);
6826 fprintf (dump_file, "\n");
6837 /* Simplify a switch statement using the value range of the switch
6841 simplify_switch_using_ranges (gimple stmt)
6843 tree op = gimple_switch_index (stmt);
6848 size_t i = 0, j = 0, n, n2;
6852 if (TREE_CODE (op) == SSA_NAME)
6854 vr = get_value_range (op);
6856 /* We can only handle integer ranges. */
6857 if (vr->type != VR_RANGE
6858 || symbolic_range_p (vr))
6861 /* Find case label for min/max of the value range. */
6862 take_default = !find_case_label_range (stmt, vr->min, vr->max, &i, &j);
6864 else if (TREE_CODE (op) == INTEGER_CST)
6866 take_default = !find_case_label_index (stmt, 1, op, &i);
6880 n = gimple_switch_num_labels (stmt);
6882 /* Bail out if this is just all edges taken. */
6888 /* Build a new vector of taken case labels. */
6889 vec2 = make_tree_vec (j - i + 1 + (int)take_default);
6892 /* Add the default edge, if necessary. */
6894 TREE_VEC_ELT (vec2, n2++) = gimple_switch_default_label (stmt);
6896 for (; i <= j; ++i, ++n2)
6897 TREE_VEC_ELT (vec2, n2) = gimple_switch_label (stmt, i);
6899 /* Mark needed edges. */
6900 for (i = 0; i < n2; ++i)
6902 e = find_edge (gimple_bb (stmt),
6903 label_to_block (CASE_LABEL (TREE_VEC_ELT (vec2, i))));
6904 e->aux = (void *)-1;
6907 /* Queue not needed edges for later removal. */
6908 FOR_EACH_EDGE (e, ei, gimple_bb (stmt)->succs)
6910 if (e->aux == (void *)-1)
6916 if (dump_file && (dump_flags & TDF_DETAILS))
6918 fprintf (dump_file, "removing unreachable case label\n");
6920 VEC_safe_push (edge, heap, to_remove_edges, e);
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 /* Stack of dest,src equivalency pairs that need to be restored after
6986 each attempt to thread a block's incoming edge to an outgoing edge.
6988 A NULL entry is used to mark the end of pairs which need to be
6990 static VEC(tree,heap) *stack;
6992 /* A trivial wrapper so that we can present the generic jump threading
6993 code with a simple API for simplifying statements. STMT is the
6994 statement we want to simplify, WITHIN_STMT provides the location
6995 for any overflow warnings. */
6998 simplify_stmt_for_jump_threading (gimple stmt, gimple within_stmt)
7000 /* We only use VRP information to simplify conditionals. This is
7001 overly conservative, but it's unclear if doing more would be
7002 worth the compile time cost. */
7003 if (gimple_code (stmt) != GIMPLE_COND)
7006 return vrp_evaluate_conditional (gimple_cond_code (stmt),
7007 gimple_cond_lhs (stmt),
7008 gimple_cond_rhs (stmt), within_stmt);
7011 /* Blocks which have more than one predecessor and more than
7012 one successor present jump threading opportunities, i.e.,
7013 when the block is reached from a specific predecessor, we
7014 may be able to determine which of the outgoing edges will
7015 be traversed. When this optimization applies, we are able
7016 to avoid conditionals at runtime and we may expose secondary
7017 optimization opportunities.
7019 This routine is effectively a driver for the generic jump
7020 threading code. It basically just presents the generic code
7021 with edges that may be suitable for jump threading.
7023 Unlike DOM, we do not iterate VRP if jump threading was successful.
7024 While iterating may expose new opportunities for VRP, it is expected
7025 those opportunities would be very limited and the compile time cost
7026 to expose those opportunities would be significant.
7028 As jump threading opportunities are discovered, they are registered
7029 for later realization. */
7032 identify_jump_threads (void)
7039 /* Ugh. When substituting values earlier in this pass we can
7040 wipe the dominance information. So rebuild the dominator
7041 information as we need it within the jump threading code. */
7042 calculate_dominance_info (CDI_DOMINATORS);
7044 /* We do not allow VRP information to be used for jump threading
7045 across a back edge in the CFG. Otherwise it becomes too
7046 difficult to avoid eliminating loop exit tests. Of course
7047 EDGE_DFS_BACK is not accurate at this time so we have to
7049 mark_dfs_back_edges ();
7051 /* Do not thread across edges we are about to remove. Just marking
7052 them as EDGE_DFS_BACK will do. */
7053 for (i = 0; VEC_iterate (edge, to_remove_edges, i, e); ++i)
7054 e->flags |= EDGE_DFS_BACK;
7056 /* Allocate our unwinder stack to unwind any temporary equivalences
7057 that might be recorded. */
7058 stack = VEC_alloc (tree, heap, 20);
7060 /* To avoid lots of silly node creation, we create a single
7061 conditional and just modify it in-place when attempting to
7063 dummy = gimple_build_cond (EQ_EXPR,
7064 integer_zero_node, integer_zero_node,
7067 /* Walk through all the blocks finding those which present a
7068 potential jump threading opportunity. We could set this up
7069 as a dominator walker and record data during the walk, but
7070 I doubt it's worth the effort for the classes of jump
7071 threading opportunities we are trying to identify at this
7072 point in compilation. */
7077 /* If the generic jump threading code does not find this block
7078 interesting, then there is nothing to do. */
7079 if (! potentially_threadable_block (bb))
7082 /* We only care about blocks ending in a COND_EXPR. While there
7083 may be some value in handling SWITCH_EXPR here, I doubt it's
7084 terribly important. */
7085 last = gsi_stmt (gsi_last_bb (bb));
7086 if (gimple_code (last) != GIMPLE_COND)
7089 /* We're basically looking for any kind of conditional with
7090 integral type arguments. */
7091 if (TREE_CODE (gimple_cond_lhs (last)) == SSA_NAME
7092 && INTEGRAL_TYPE_P (TREE_TYPE (gimple_cond_lhs (last)))
7093 && (TREE_CODE (gimple_cond_rhs (last)) == SSA_NAME
7094 || is_gimple_min_invariant (gimple_cond_rhs (last)))
7095 && INTEGRAL_TYPE_P (TREE_TYPE (gimple_cond_rhs (last))))
7099 /* We've got a block with multiple predecessors and multiple
7100 successors which also ends in a suitable conditional. For
7101 each predecessor, see if we can thread it to a specific
7103 FOR_EACH_EDGE (e, ei, bb->preds)
7105 /* Do not thread across back edges or abnormal edges
7107 if (e->flags & (EDGE_DFS_BACK | EDGE_COMPLEX))
7110 thread_across_edge (dummy, e, true, &stack,
7111 simplify_stmt_for_jump_threading);
7116 /* We do not actually update the CFG or SSA graphs at this point as
7117 ASSERT_EXPRs are still in the IL and cfg cleanup code does not yet
7118 handle ASSERT_EXPRs gracefully. */
7121 /* We identified all the jump threading opportunities earlier, but could
7122 not transform the CFG at that time. This routine transforms the
7123 CFG and arranges for the dominator tree to be rebuilt if necessary.
7125 Note the SSA graph update will occur during the normal TODO
7126 processing by the pass manager. */
7128 finalize_jump_threads (void)
7130 thread_through_all_blocks (false);
7131 VEC_free (tree, heap, stack);
7135 /* Traverse all the blocks folding conditionals with known ranges. */
7141 prop_value_t *single_val_range;
7142 bool do_value_subst_p;
7146 fprintf (dump_file, "\nValue ranges after VRP:\n\n");
7147 dump_all_value_ranges (dump_file);
7148 fprintf (dump_file, "\n");
7151 /* We may have ended with ranges that have exactly one value. Those
7152 values can be substituted as any other copy/const propagated
7153 value using substitute_and_fold. */
7154 single_val_range = XCNEWVEC (prop_value_t, num_ssa_names);
7156 do_value_subst_p = false;
7157 for (i = 0; i < num_ssa_names; i++)
7159 && vr_value[i]->type == VR_RANGE
7160 && vr_value[i]->min == vr_value[i]->max)
7162 single_val_range[i].value = vr_value[i]->min;
7163 do_value_subst_p = true;
7166 if (!do_value_subst_p)
7168 /* We found no single-valued ranges, don't waste time trying to
7169 do single value substitution in substitute_and_fold. */
7170 free (single_val_range);
7171 single_val_range = NULL;
7174 substitute_and_fold (single_val_range, true);
7176 if (warn_array_bounds)
7177 check_all_array_refs ();
7179 /* We must identify jump threading opportunities before we release
7180 the datastructures built by VRP. */
7181 identify_jump_threads ();
7183 /* Free allocated memory. */
7184 for (i = 0; i < num_ssa_names; i++)
7187 BITMAP_FREE (vr_value[i]->equiv);
7191 free (single_val_range);
7193 free (vr_phi_edge_counts);
7195 /* So that we can distinguish between VRP data being available
7196 and not available. */
7198 vr_phi_edge_counts = NULL;
7202 /* Main entry point to VRP (Value Range Propagation). This pass is
7203 loosely based on J. R. C. Patterson, ``Accurate Static Branch
7204 Prediction by Value Range Propagation,'' in SIGPLAN Conference on
7205 Programming Language Design and Implementation, pp. 67-78, 1995.
7206 Also available at http://citeseer.ist.psu.edu/patterson95accurate.html
7208 This is essentially an SSA-CCP pass modified to deal with ranges
7209 instead of constants.
7211 While propagating ranges, we may find that two or more SSA name
7212 have equivalent, though distinct ranges. For instance,
7215 2 p_4 = ASSERT_EXPR <p_3, p_3 != 0>
7217 4 p_5 = ASSERT_EXPR <p_4, p_4 == q_2>;
7221 In the code above, pointer p_5 has range [q_2, q_2], but from the
7222 code we can also determine that p_5 cannot be NULL and, if q_2 had
7223 a non-varying range, p_5's range should also be compatible with it.
7225 These equivalences are created by two expressions: ASSERT_EXPR and
7226 copy operations. Since p_5 is an assertion on p_4, and p_4 was the
7227 result of another assertion, then we can use the fact that p_5 and
7228 p_4 are equivalent when evaluating p_5's range.
7230 Together with value ranges, we also propagate these equivalences
7231 between names so that we can take advantage of information from
7232 multiple ranges when doing final replacement. Note that this
7233 equivalency relation is transitive but not symmetric.
7235 In the example above, p_5 is equivalent to p_4, q_2 and p_3, but we
7236 cannot assert that q_2 is equivalent to p_5 because q_2 may be used
7237 in contexts where that assertion does not hold (e.g., in line 6).
7239 TODO, the main difference between this pass and Patterson's is that
7240 we do not propagate edge probabilities. We only compute whether
7241 edges can be taken or not. That is, instead of having a spectrum
7242 of jump probabilities between 0 and 1, we only deal with 0, 1 and
7243 DON'T KNOW. In the future, it may be worthwhile to propagate
7244 probabilities to aid branch prediction. */
7253 loop_optimizer_init (LOOPS_NORMAL | LOOPS_HAVE_RECORDED_EXITS);
7254 rewrite_into_loop_closed_ssa (NULL, TODO_update_ssa);
7257 insert_range_assertions ();
7259 to_remove_edges = VEC_alloc (edge, heap, 10);
7260 to_update_switch_stmts = VEC_alloc (switch_update, heap, 5);
7261 threadedge_initialize_values ();
7264 ssa_propagate (vrp_visit_stmt, vrp_visit_phi_node);
7267 /* ASSERT_EXPRs must be removed before finalizing jump threads
7268 as finalizing jump threads calls the CFG cleanup code which
7269 does not properly handle ASSERT_EXPRs. */
7270 remove_range_assertions ();
7272 /* If we exposed any new variables, go ahead and put them into
7273 SSA form now, before we handle jump threading. This simplifies
7274 interactions between rewriting of _DECL nodes into SSA form
7275 and rewriting SSA_NAME nodes into SSA form after block
7276 duplication and CFG manipulation. */
7277 update_ssa (TODO_update_ssa);
7279 finalize_jump_threads ();
7281 /* Remove dead edges from SWITCH_EXPR optimization. This leaves the
7282 CFG in a broken state and requires a cfg_cleanup run. */
7283 for (i = 0; VEC_iterate (edge, to_remove_edges, i, e); ++i)
7285 /* Update SWITCH_EXPR case label vector. */
7286 for (i = 0; VEC_iterate (switch_update, to_update_switch_stmts, i, su); ++i)
7289 size_t n = TREE_VEC_LENGTH (su->vec);
7291 gimple_switch_set_num_labels (su->stmt, n);
7292 for (j = 0; j < n; j++)
7293 gimple_switch_set_label (su->stmt, j, TREE_VEC_ELT (su->vec, j));
7294 /* As we may have replaced the default label with a regular one
7295 make sure to make it a real default label again. This ensures
7296 optimal expansion. */
7297 label = gimple_switch_default_label (su->stmt);
7298 CASE_LOW (label) = NULL_TREE;
7299 CASE_HIGH (label) = NULL_TREE;
7302 if (VEC_length (edge, to_remove_edges) > 0)
7303 free_dominance_info (CDI_DOMINATORS);
7305 VEC_free (edge, heap, to_remove_edges);
7306 VEC_free (switch_update, heap, to_update_switch_stmts);
7307 threadedge_finalize_values ();
7310 loop_optimizer_finalize ();
7317 return flag_tree_vrp != 0;
7320 struct gimple_opt_pass pass_vrp =
7325 gate_vrp, /* gate */
7326 execute_vrp, /* execute */
7329 0, /* static_pass_number */
7330 TV_TREE_VRP, /* tv_id */
7331 PROP_ssa, /* properties_required */
7332 0, /* properties_provided */
7333 0, /* properties_destroyed */
7334 0, /* todo_flags_start */
7339 | TODO_update_ssa /* todo_flags_finish */