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 TYPEs base type. */
127 vrp_val_max (const_tree type)
129 if (!INTEGRAL_TYPE_P (type))
132 /* For integer sub-types the values for the base type are relevant. */
133 if (TREE_TYPE (type))
134 type = TREE_TYPE (type);
136 return TYPE_MAX_VALUE (type);
139 /* Return the minimum value for TYPEs base type. */
142 vrp_val_min (const_tree type)
144 if (!INTEGRAL_TYPE_P (type))
147 /* For integer sub-types the values for the base type are relevant. */
148 if (TREE_TYPE (type))
149 type = TREE_TYPE (type);
151 return TYPE_MIN_VALUE (type);
154 /* Return whether VAL is equal to the maximum value of its type. This
155 will be true for a positive overflow infinity. We can't do a
156 simple equality comparison with TYPE_MAX_VALUE because C typedefs
157 and Ada subtypes can produce types whose TYPE_MAX_VALUE is not ==
158 to the integer constant with the same value in the type. */
161 vrp_val_is_max (const_tree val)
163 tree type_max = vrp_val_max (TREE_TYPE (val));
164 return (val == type_max
165 || (type_max != NULL_TREE
166 && operand_equal_p (val, type_max, 0)));
169 /* Return whether VAL is equal to the minimum value of its type. This
170 will be true for a negative overflow infinity. */
173 vrp_val_is_min (const_tree val)
175 tree type_min = vrp_val_min (TREE_TYPE (val));
176 return (val == type_min
177 || (type_min != NULL_TREE
178 && operand_equal_p (val, type_min, 0)));
182 /* Return whether TYPE should use an overflow infinity distinct from
183 TYPE_{MIN,MAX}_VALUE. We use an overflow infinity value to
184 represent a signed overflow during VRP computations. An infinity
185 is distinct from a half-range, which will go from some number to
186 TYPE_{MIN,MAX}_VALUE. */
189 needs_overflow_infinity (const_tree type)
191 return (INTEGRAL_TYPE_P (type)
192 && !TYPE_OVERFLOW_WRAPS (type)
193 /* Integer sub-types never overflow as they are never
194 operands of arithmetic operators. */
195 && !(TREE_TYPE (type) && TREE_TYPE (type) != type));
198 /* Return whether TYPE can support our overflow infinity
199 representation: we use the TREE_OVERFLOW flag, which only exists
200 for constants. If TYPE doesn't support this, we don't optimize
201 cases which would require signed overflow--we drop them to
205 supports_overflow_infinity (const_tree type)
207 tree min = vrp_val_min (type), max = vrp_val_max (type);
208 #ifdef ENABLE_CHECKING
209 gcc_assert (needs_overflow_infinity (type));
211 return (min != NULL_TREE
212 && CONSTANT_CLASS_P (min)
214 && CONSTANT_CLASS_P (max));
217 /* VAL is the maximum or minimum value of a type. Return a
218 corresponding overflow infinity. */
221 make_overflow_infinity (tree val)
223 #ifdef ENABLE_CHECKING
224 gcc_assert (val != NULL_TREE && CONSTANT_CLASS_P (val));
226 val = copy_node (val);
227 TREE_OVERFLOW (val) = 1;
231 /* Return a negative overflow infinity for TYPE. */
234 negative_overflow_infinity (tree type)
236 #ifdef ENABLE_CHECKING
237 gcc_assert (supports_overflow_infinity (type));
239 return make_overflow_infinity (vrp_val_min (type));
242 /* Return a positive overflow infinity for TYPE. */
245 positive_overflow_infinity (tree type)
247 #ifdef ENABLE_CHECKING
248 gcc_assert (supports_overflow_infinity (type));
250 return make_overflow_infinity (vrp_val_max (type));
253 /* Return whether VAL is a negative overflow infinity. */
256 is_negative_overflow_infinity (const_tree val)
258 return (needs_overflow_infinity (TREE_TYPE (val))
259 && CONSTANT_CLASS_P (val)
260 && TREE_OVERFLOW (val)
261 && vrp_val_is_min (val));
264 /* Return whether VAL is a positive overflow infinity. */
267 is_positive_overflow_infinity (const_tree val)
269 return (needs_overflow_infinity (TREE_TYPE (val))
270 && CONSTANT_CLASS_P (val)
271 && TREE_OVERFLOW (val)
272 && vrp_val_is_max (val));
275 /* Return whether VAL is a positive or negative overflow infinity. */
278 is_overflow_infinity (const_tree val)
280 return (needs_overflow_infinity (TREE_TYPE (val))
281 && CONSTANT_CLASS_P (val)
282 && TREE_OVERFLOW (val)
283 && (vrp_val_is_min (val) || vrp_val_is_max (val)));
286 /* Return whether STMT has a constant rhs that is_overflow_infinity. */
289 stmt_overflow_infinity (gimple stmt)
291 if (is_gimple_assign (stmt)
292 && get_gimple_rhs_class (gimple_assign_rhs_code (stmt)) ==
294 return is_overflow_infinity (gimple_assign_rhs1 (stmt));
298 /* If VAL is now an overflow infinity, return VAL. Otherwise, return
299 the same value with TREE_OVERFLOW clear. This can be used to avoid
300 confusing a regular value with an overflow value. */
303 avoid_overflow_infinity (tree val)
305 if (!is_overflow_infinity (val))
308 if (vrp_val_is_max (val))
309 return vrp_val_max (TREE_TYPE (val));
312 #ifdef ENABLE_CHECKING
313 gcc_assert (vrp_val_is_min (val));
315 return vrp_val_min (TREE_TYPE (val));
320 /* Return true if ARG is marked with the nonnull attribute in the
321 current function signature. */
324 nonnull_arg_p (const_tree arg)
326 tree t, attrs, fntype;
327 unsigned HOST_WIDE_INT arg_num;
329 gcc_assert (TREE_CODE (arg) == PARM_DECL && POINTER_TYPE_P (TREE_TYPE (arg)));
331 /* The static chain decl is always non null. */
332 if (arg == cfun->static_chain_decl)
335 fntype = TREE_TYPE (current_function_decl);
336 attrs = lookup_attribute ("nonnull", TYPE_ATTRIBUTES (fntype));
338 /* If "nonnull" wasn't specified, we know nothing about the argument. */
339 if (attrs == NULL_TREE)
342 /* If "nonnull" applies to all the arguments, then ARG is non-null. */
343 if (TREE_VALUE (attrs) == NULL_TREE)
346 /* Get the position number for ARG in the function signature. */
347 for (arg_num = 1, t = DECL_ARGUMENTS (current_function_decl);
349 t = TREE_CHAIN (t), arg_num++)
355 gcc_assert (t == arg);
357 /* Now see if ARG_NUM is mentioned in the nonnull list. */
358 for (t = TREE_VALUE (attrs); t; t = TREE_CHAIN (t))
360 if (compare_tree_int (TREE_VALUE (t), arg_num) == 0)
368 /* Set value range VR to VR_VARYING. */
371 set_value_range_to_varying (value_range_t *vr)
373 vr->type = VR_VARYING;
374 vr->min = vr->max = NULL_TREE;
376 bitmap_clear (vr->equiv);
380 /* Set value range VR to {T, MIN, MAX, EQUIV}. */
383 set_value_range (value_range_t *vr, enum value_range_type t, tree min,
384 tree max, bitmap equiv)
386 #if defined ENABLE_CHECKING
387 /* Check the validity of the range. */
388 if (t == VR_RANGE || t == VR_ANTI_RANGE)
392 gcc_assert (min && max);
394 if (INTEGRAL_TYPE_P (TREE_TYPE (min)) && t == VR_ANTI_RANGE)
395 gcc_assert (!vrp_val_is_min (min) || !vrp_val_is_max (max));
397 cmp = compare_values (min, max);
398 gcc_assert (cmp == 0 || cmp == -1 || cmp == -2);
400 if (needs_overflow_infinity (TREE_TYPE (min)))
401 gcc_assert (!is_overflow_infinity (min)
402 || !is_overflow_infinity (max));
405 if (t == VR_UNDEFINED || t == VR_VARYING)
406 gcc_assert (min == NULL_TREE && max == NULL_TREE);
408 if (t == VR_UNDEFINED || t == VR_VARYING)
409 gcc_assert (equiv == NULL || bitmap_empty_p (equiv));
416 /* Since updating the equivalence set involves deep copying the
417 bitmaps, only do it if absolutely necessary. */
418 if (vr->equiv == NULL
420 vr->equiv = BITMAP_ALLOC (NULL);
422 if (equiv != vr->equiv)
424 if (equiv && !bitmap_empty_p (equiv))
425 bitmap_copy (vr->equiv, equiv);
427 bitmap_clear (vr->equiv);
432 /* Set value range VR to the canonical form of {T, MIN, MAX, EQUIV}.
433 This means adjusting T, MIN and MAX representing the case of a
434 wrapping range with MAX < MIN covering [MIN, type_max] U [type_min, MAX]
435 as anti-rage ~[MAX+1, MIN-1]. Likewise for wrapping anti-ranges.
436 In corner cases where MAX+1 or MIN-1 wraps this will fall back
438 This routine exists to ease canonicalization in the case where we
439 extract ranges from var + CST op limit. */
442 set_and_canonicalize_value_range (value_range_t *vr, enum value_range_type t,
443 tree min, tree max, bitmap equiv)
445 /* Nothing to canonicalize for symbolic or unknown or varying ranges. */
447 && t != VR_ANTI_RANGE)
448 || TREE_CODE (min) != INTEGER_CST
449 || TREE_CODE (max) != INTEGER_CST)
451 set_value_range (vr, t, min, max, equiv);
455 /* Wrong order for min and max, to swap them and the VR type we need
457 if (tree_int_cst_lt (max, min))
459 tree one = build_int_cst (TREE_TYPE (min), 1);
460 tree tmp = int_const_binop (PLUS_EXPR, max, one, 0);
461 max = int_const_binop (MINUS_EXPR, min, one, 0);
464 /* There's one corner case, if we had [C+1, C] before we now have
465 that again. But this represents an empty value range, so drop
466 to varying in this case. */
467 if (tree_int_cst_lt (max, min))
469 set_value_range_to_varying (vr);
473 t = t == VR_RANGE ? VR_ANTI_RANGE : VR_RANGE;
476 /* Anti-ranges that can be represented as ranges should be so. */
477 if (t == VR_ANTI_RANGE)
479 bool is_min = vrp_val_is_min (min);
480 bool is_max = vrp_val_is_max (max);
482 if (is_min && is_max)
484 /* We cannot deal with empty ranges, drop to varying. */
485 set_value_range_to_varying (vr);
489 /* As a special exception preserve non-null ranges. */
490 && !(TYPE_UNSIGNED (TREE_TYPE (min))
491 && integer_zerop (max)))
493 tree one = build_int_cst (TREE_TYPE (max), 1);
494 min = int_const_binop (PLUS_EXPR, max, one, 0);
495 max = vrp_val_max (TREE_TYPE (max));
500 tree one = build_int_cst (TREE_TYPE (min), 1);
501 max = int_const_binop (MINUS_EXPR, min, one, 0);
502 min = vrp_val_min (TREE_TYPE (min));
507 set_value_range (vr, t, min, max, equiv);
510 /* Copy value range FROM into value range TO. */
513 copy_value_range (value_range_t *to, value_range_t *from)
515 set_value_range (to, from->type, from->min, from->max, from->equiv);
518 /* Set value range VR to a single value. This function is only called
519 with values we get from statements, and exists to clear the
520 TREE_OVERFLOW flag so that we don't think we have an overflow
521 infinity when we shouldn't. */
524 set_value_range_to_value (value_range_t *vr, tree val, bitmap equiv)
526 gcc_assert (is_gimple_min_invariant (val));
527 val = avoid_overflow_infinity (val);
528 set_value_range (vr, VR_RANGE, val, val, equiv);
531 /* Set value range VR to a non-negative range of type TYPE.
532 OVERFLOW_INFINITY indicates whether to use an overflow infinity
533 rather than TYPE_MAX_VALUE; this should be true if we determine
534 that the range is nonnegative based on the assumption that signed
535 overflow does not occur. */
538 set_value_range_to_nonnegative (value_range_t *vr, tree type,
539 bool overflow_infinity)
543 if (overflow_infinity && !supports_overflow_infinity (type))
545 set_value_range_to_varying (vr);
549 zero = build_int_cst (type, 0);
550 set_value_range (vr, VR_RANGE, zero,
552 ? positive_overflow_infinity (type)
553 : TYPE_MAX_VALUE (type)),
557 /* Set value range VR to a non-NULL range of type TYPE. */
560 set_value_range_to_nonnull (value_range_t *vr, tree type)
562 tree zero = build_int_cst (type, 0);
563 set_value_range (vr, VR_ANTI_RANGE, zero, zero, vr->equiv);
567 /* Set value range VR to a NULL range of type TYPE. */
570 set_value_range_to_null (value_range_t *vr, tree type)
572 set_value_range_to_value (vr, build_int_cst (type, 0), vr->equiv);
576 /* Set value range VR to a range of a truthvalue of type TYPE. */
579 set_value_range_to_truthvalue (value_range_t *vr, tree type)
581 if (TYPE_PRECISION (type) == 1)
582 set_value_range_to_varying (vr);
584 set_value_range (vr, VR_RANGE,
585 build_int_cst (type, 0), build_int_cst (type, 1),
590 /* Set value range VR to VR_UNDEFINED. */
593 set_value_range_to_undefined (value_range_t *vr)
595 vr->type = VR_UNDEFINED;
596 vr->min = vr->max = NULL_TREE;
598 bitmap_clear (vr->equiv);
602 /* If abs (min) < abs (max), set VR to [-max, max], if
603 abs (min) >= abs (max), set VR to [-min, min]. */
606 abs_extent_range (value_range_t *vr, tree min, tree max)
610 gcc_assert (TREE_CODE (min) == INTEGER_CST);
611 gcc_assert (TREE_CODE (max) == INTEGER_CST);
612 gcc_assert (INTEGRAL_TYPE_P (TREE_TYPE (min)));
613 gcc_assert (!TYPE_UNSIGNED (TREE_TYPE (min)));
614 min = fold_unary (ABS_EXPR, TREE_TYPE (min), min);
615 max = fold_unary (ABS_EXPR, TREE_TYPE (max), max);
616 if (TREE_OVERFLOW (min) || TREE_OVERFLOW (max))
618 set_value_range_to_varying (vr);
621 cmp = compare_values (min, max);
623 min = fold_unary (NEGATE_EXPR, TREE_TYPE (min), max);
624 else if (cmp == 0 || cmp == 1)
627 min = fold_unary (NEGATE_EXPR, TREE_TYPE (min), min);
631 set_value_range_to_varying (vr);
634 set_and_canonicalize_value_range (vr, VR_RANGE, min, max, NULL);
638 /* Return value range information for VAR.
640 If we have no values ranges recorded (ie, VRP is not running), then
641 return NULL. Otherwise create an empty range if none existed for VAR. */
643 static value_range_t *
644 get_value_range (const_tree var)
648 unsigned ver = SSA_NAME_VERSION (var);
650 /* If we have no recorded ranges, then return NULL. */
658 /* Create a default value range. */
659 vr_value[ver] = vr = XCNEW (value_range_t);
661 /* Defer allocating the equivalence set. */
664 /* If VAR is a default definition, the variable can take any value
666 sym = SSA_NAME_VAR (var);
667 if (SSA_NAME_IS_DEFAULT_DEF (var))
669 /* Try to use the "nonnull" attribute to create ~[0, 0]
670 anti-ranges for pointers. Note that this is only valid with
671 default definitions of PARM_DECLs. */
672 if (TREE_CODE (sym) == PARM_DECL
673 && POINTER_TYPE_P (TREE_TYPE (sym))
674 && nonnull_arg_p (sym))
675 set_value_range_to_nonnull (vr, TREE_TYPE (sym));
677 set_value_range_to_varying (vr);
683 /* Return true, if VAL1 and VAL2 are equal values for VRP purposes. */
686 vrp_operand_equal_p (const_tree val1, const_tree val2)
690 if (!val1 || !val2 || !operand_equal_p (val1, val2, 0))
692 if (is_overflow_infinity (val1))
693 return is_overflow_infinity (val2);
697 /* Return true, if the bitmaps B1 and B2 are equal. */
700 vrp_bitmap_equal_p (const_bitmap b1, const_bitmap b2)
704 && bitmap_equal_p (b1, b2)));
707 /* Update the value range and equivalence set for variable VAR to
708 NEW_VR. Return true if NEW_VR is different from VAR's previous
711 NOTE: This function assumes that NEW_VR is a temporary value range
712 object created for the sole purpose of updating VAR's range. The
713 storage used by the equivalence set from NEW_VR will be freed by
714 this function. Do not call update_value_range when NEW_VR
715 is the range object associated with another SSA name. */
718 update_value_range (const_tree var, value_range_t *new_vr)
720 value_range_t *old_vr;
723 /* Update the value range, if necessary. */
724 old_vr = get_value_range (var);
725 is_new = old_vr->type != new_vr->type
726 || !vrp_operand_equal_p (old_vr->min, new_vr->min)
727 || !vrp_operand_equal_p (old_vr->max, new_vr->max)
728 || !vrp_bitmap_equal_p (old_vr->equiv, new_vr->equiv);
731 set_value_range (old_vr, new_vr->type, new_vr->min, new_vr->max,
734 BITMAP_FREE (new_vr->equiv);
740 /* Add VAR and VAR's equivalence set to EQUIV. This is the central
741 point where equivalence processing can be turned on/off. */
744 add_equivalence (bitmap *equiv, const_tree var)
746 unsigned ver = SSA_NAME_VERSION (var);
747 value_range_t *vr = vr_value[ver];
750 *equiv = BITMAP_ALLOC (NULL);
751 bitmap_set_bit (*equiv, ver);
753 bitmap_ior_into (*equiv, vr->equiv);
757 /* Return true if VR is ~[0, 0]. */
760 range_is_nonnull (value_range_t *vr)
762 return vr->type == VR_ANTI_RANGE
763 && integer_zerop (vr->min)
764 && integer_zerop (vr->max);
768 /* Return true if VR is [0, 0]. */
771 range_is_null (value_range_t *vr)
773 return vr->type == VR_RANGE
774 && integer_zerop (vr->min)
775 && integer_zerop (vr->max);
779 /* Return true if value range VR involves at least one symbol. */
782 symbolic_range_p (value_range_t *vr)
784 return (!is_gimple_min_invariant (vr->min)
785 || !is_gimple_min_invariant (vr->max));
788 /* Return true if value range VR uses an overflow infinity. */
791 overflow_infinity_range_p (value_range_t *vr)
793 return (vr->type == VR_RANGE
794 && (is_overflow_infinity (vr->min)
795 || is_overflow_infinity (vr->max)));
798 /* Return false if we can not make a valid comparison based on VR;
799 this will be the case if it uses an overflow infinity and overflow
800 is not undefined (i.e., -fno-strict-overflow is in effect).
801 Otherwise return true, and set *STRICT_OVERFLOW_P to true if VR
802 uses an overflow infinity. */
805 usable_range_p (value_range_t *vr, bool *strict_overflow_p)
807 gcc_assert (vr->type == VR_RANGE);
808 if (is_overflow_infinity (vr->min))
810 *strict_overflow_p = true;
811 if (!TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (vr->min)))
814 if (is_overflow_infinity (vr->max))
816 *strict_overflow_p = true;
817 if (!TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (vr->max)))
824 /* Like tree_expr_nonnegative_warnv_p, but this function uses value
825 ranges obtained so far. */
828 vrp_expr_computes_nonnegative (tree expr, bool *strict_overflow_p)
830 return (tree_expr_nonnegative_warnv_p (expr, strict_overflow_p)
831 || (TREE_CODE (expr) == SSA_NAME
832 && ssa_name_nonnegative_p (expr)));
835 /* Return true if the result of assignment STMT is know to be non-negative.
836 If the return value is based on the assumption that signed overflow is
837 undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't change
838 *STRICT_OVERFLOW_P.*/
841 gimple_assign_nonnegative_warnv_p (gimple stmt, bool *strict_overflow_p)
843 enum tree_code code = gimple_assign_rhs_code (stmt);
844 switch (get_gimple_rhs_class (code))
846 case GIMPLE_UNARY_RHS:
847 return tree_unary_nonnegative_warnv_p (gimple_assign_rhs_code (stmt),
848 gimple_expr_type (stmt),
849 gimple_assign_rhs1 (stmt),
851 case GIMPLE_BINARY_RHS:
852 return tree_binary_nonnegative_warnv_p (gimple_assign_rhs_code (stmt),
853 gimple_expr_type (stmt),
854 gimple_assign_rhs1 (stmt),
855 gimple_assign_rhs2 (stmt),
857 case GIMPLE_SINGLE_RHS:
858 return tree_single_nonnegative_warnv_p (gimple_assign_rhs1 (stmt),
860 case GIMPLE_INVALID_RHS:
867 /* Return true if return value of call STMT is know to be non-negative.
868 If the return value is based on the assumption that signed overflow is
869 undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't change
870 *STRICT_OVERFLOW_P.*/
873 gimple_call_nonnegative_warnv_p (gimple stmt, bool *strict_overflow_p)
875 tree arg0 = gimple_call_num_args (stmt) > 0 ?
876 gimple_call_arg (stmt, 0) : NULL_TREE;
877 tree arg1 = gimple_call_num_args (stmt) > 1 ?
878 gimple_call_arg (stmt, 1) : NULL_TREE;
880 return tree_call_nonnegative_warnv_p (gimple_expr_type (stmt),
881 gimple_call_fndecl (stmt),
887 /* Return true if STMT is know to to compute a non-negative value.
888 If the return value is based on the assumption that signed overflow is
889 undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't change
890 *STRICT_OVERFLOW_P.*/
893 gimple_stmt_nonnegative_warnv_p (gimple stmt, bool *strict_overflow_p)
895 switch (gimple_code (stmt))
898 return gimple_assign_nonnegative_warnv_p (stmt, strict_overflow_p);
900 return gimple_call_nonnegative_warnv_p (stmt, strict_overflow_p);
906 /* Return true if the result of assignment STMT is know to be non-zero.
907 If the return value is based on the assumption that signed overflow is
908 undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't change
909 *STRICT_OVERFLOW_P.*/
912 gimple_assign_nonzero_warnv_p (gimple stmt, bool *strict_overflow_p)
914 enum tree_code code = gimple_assign_rhs_code (stmt);
915 switch (get_gimple_rhs_class (code))
917 case GIMPLE_UNARY_RHS:
918 return tree_unary_nonzero_warnv_p (gimple_assign_rhs_code (stmt),
919 gimple_expr_type (stmt),
920 gimple_assign_rhs1 (stmt),
922 case GIMPLE_BINARY_RHS:
923 return tree_binary_nonzero_warnv_p (gimple_assign_rhs_code (stmt),
924 gimple_expr_type (stmt),
925 gimple_assign_rhs1 (stmt),
926 gimple_assign_rhs2 (stmt),
928 case GIMPLE_SINGLE_RHS:
929 return tree_single_nonzero_warnv_p (gimple_assign_rhs1 (stmt),
931 case GIMPLE_INVALID_RHS:
938 /* Return true if STMT is know to to compute a non-zero value.
939 If the return value is based on the assumption that signed overflow is
940 undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't change
941 *STRICT_OVERFLOW_P.*/
944 gimple_stmt_nonzero_warnv_p (gimple stmt, bool *strict_overflow_p)
946 switch (gimple_code (stmt))
949 return gimple_assign_nonzero_warnv_p (stmt, strict_overflow_p);
951 return gimple_alloca_call_p (stmt);
957 /* Like tree_expr_nonzero_warnv_p, but this function uses value ranges
961 vrp_stmt_computes_nonzero (gimple stmt, bool *strict_overflow_p)
963 if (gimple_stmt_nonzero_warnv_p (stmt, strict_overflow_p))
966 /* If we have an expression of the form &X->a, then the expression
967 is nonnull if X is nonnull. */
968 if (is_gimple_assign (stmt)
969 && gimple_assign_rhs_code (stmt) == ADDR_EXPR)
971 tree expr = gimple_assign_rhs1 (stmt);
972 tree base = get_base_address (TREE_OPERAND (expr, 0));
974 if (base != NULL_TREE
975 && TREE_CODE (base) == INDIRECT_REF
976 && TREE_CODE (TREE_OPERAND (base, 0)) == SSA_NAME)
978 value_range_t *vr = get_value_range (TREE_OPERAND (base, 0));
979 if (range_is_nonnull (vr))
987 /* Returns true if EXPR is a valid value (as expected by compare_values) --
988 a gimple invariant, or SSA_NAME +- CST. */
991 valid_value_p (tree expr)
993 if (TREE_CODE (expr) == SSA_NAME)
996 if (TREE_CODE (expr) == PLUS_EXPR
997 || TREE_CODE (expr) == MINUS_EXPR)
998 return (TREE_CODE (TREE_OPERAND (expr, 0)) == SSA_NAME
999 && TREE_CODE (TREE_OPERAND (expr, 1)) == INTEGER_CST);
1001 return is_gimple_min_invariant (expr);
1007 -2 if those are incomparable. */
1009 operand_less_p (tree val, tree val2)
1011 /* LT is folded faster than GE and others. Inline the common case. */
1012 if (TREE_CODE (val) == INTEGER_CST && TREE_CODE (val2) == INTEGER_CST)
1014 if (TYPE_UNSIGNED (TREE_TYPE (val)))
1015 return INT_CST_LT_UNSIGNED (val, val2);
1018 if (INT_CST_LT (val, val2))
1026 fold_defer_overflow_warnings ();
1028 tcmp = fold_binary_to_constant (LT_EXPR, boolean_type_node, val, val2);
1030 fold_undefer_and_ignore_overflow_warnings ();
1033 || TREE_CODE (tcmp) != INTEGER_CST)
1036 if (!integer_zerop (tcmp))
1040 /* val >= val2, not considering overflow infinity. */
1041 if (is_negative_overflow_infinity (val))
1042 return is_negative_overflow_infinity (val2) ? 0 : 1;
1043 else if (is_positive_overflow_infinity (val2))
1044 return is_positive_overflow_infinity (val) ? 0 : 1;
1049 /* Compare two values VAL1 and VAL2. Return
1051 -2 if VAL1 and VAL2 cannot be compared at compile-time,
1054 +1 if VAL1 > VAL2, and
1057 This is similar to tree_int_cst_compare but supports pointer values
1058 and values that cannot be compared at compile time.
1060 If STRICT_OVERFLOW_P is not NULL, then set *STRICT_OVERFLOW_P to
1061 true if the return value is only valid if we assume that signed
1062 overflow is undefined. */
1065 compare_values_warnv (tree val1, tree val2, bool *strict_overflow_p)
1070 /* Below we rely on the fact that VAL1 and VAL2 are both pointers or
1072 gcc_assert (POINTER_TYPE_P (TREE_TYPE (val1))
1073 == POINTER_TYPE_P (TREE_TYPE (val2)));
1074 /* Convert the two values into the same type. This is needed because
1075 sizetype causes sign extension even for unsigned types. */
1076 val2 = fold_convert (TREE_TYPE (val1), val2);
1077 STRIP_USELESS_TYPE_CONVERSION (val2);
1079 if ((TREE_CODE (val1) == SSA_NAME
1080 || TREE_CODE (val1) == PLUS_EXPR
1081 || TREE_CODE (val1) == MINUS_EXPR)
1082 && (TREE_CODE (val2) == SSA_NAME
1083 || TREE_CODE (val2) == PLUS_EXPR
1084 || TREE_CODE (val2) == MINUS_EXPR))
1086 tree n1, c1, n2, c2;
1087 enum tree_code code1, code2;
1089 /* If VAL1 and VAL2 are of the form 'NAME [+-] CST' or 'NAME',
1090 return -1 or +1 accordingly. If VAL1 and VAL2 don't use the
1091 same name, return -2. */
1092 if (TREE_CODE (val1) == SSA_NAME)
1100 code1 = TREE_CODE (val1);
1101 n1 = TREE_OPERAND (val1, 0);
1102 c1 = TREE_OPERAND (val1, 1);
1103 if (tree_int_cst_sgn (c1) == -1)
1105 if (is_negative_overflow_infinity (c1))
1107 c1 = fold_unary_to_constant (NEGATE_EXPR, TREE_TYPE (c1), c1);
1110 code1 = code1 == MINUS_EXPR ? PLUS_EXPR : MINUS_EXPR;
1114 if (TREE_CODE (val2) == SSA_NAME)
1122 code2 = TREE_CODE (val2);
1123 n2 = TREE_OPERAND (val2, 0);
1124 c2 = TREE_OPERAND (val2, 1);
1125 if (tree_int_cst_sgn (c2) == -1)
1127 if (is_negative_overflow_infinity (c2))
1129 c2 = fold_unary_to_constant (NEGATE_EXPR, TREE_TYPE (c2), c2);
1132 code2 = code2 == MINUS_EXPR ? PLUS_EXPR : MINUS_EXPR;
1136 /* Both values must use the same name. */
1140 if (code1 == SSA_NAME
1141 && code2 == SSA_NAME)
1145 /* If overflow is defined we cannot simplify more. */
1146 if (!TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (val1)))
1149 if (strict_overflow_p != NULL
1150 && (code1 == SSA_NAME || !TREE_NO_WARNING (val1))
1151 && (code2 == SSA_NAME || !TREE_NO_WARNING (val2)))
1152 *strict_overflow_p = true;
1154 if (code1 == SSA_NAME)
1156 if (code2 == PLUS_EXPR)
1157 /* NAME < NAME + CST */
1159 else if (code2 == MINUS_EXPR)
1160 /* NAME > NAME - CST */
1163 else if (code1 == PLUS_EXPR)
1165 if (code2 == SSA_NAME)
1166 /* NAME + CST > NAME */
1168 else if (code2 == PLUS_EXPR)
1169 /* NAME + CST1 > NAME + CST2, if CST1 > CST2 */
1170 return compare_values_warnv (c1, c2, strict_overflow_p);
1171 else if (code2 == MINUS_EXPR)
1172 /* NAME + CST1 > NAME - CST2 */
1175 else if (code1 == MINUS_EXPR)
1177 if (code2 == SSA_NAME)
1178 /* NAME - CST < NAME */
1180 else if (code2 == PLUS_EXPR)
1181 /* NAME - CST1 < NAME + CST2 */
1183 else if (code2 == MINUS_EXPR)
1184 /* NAME - CST1 > NAME - CST2, if CST1 < CST2. Notice that
1185 C1 and C2 are swapped in the call to compare_values. */
1186 return compare_values_warnv (c2, c1, strict_overflow_p);
1192 /* We cannot compare non-constants. */
1193 if (!is_gimple_min_invariant (val1) || !is_gimple_min_invariant (val2))
1196 if (!POINTER_TYPE_P (TREE_TYPE (val1)))
1198 /* We cannot compare overflowed values, except for overflow
1200 if (TREE_OVERFLOW (val1) || TREE_OVERFLOW (val2))
1202 if (strict_overflow_p != NULL)
1203 *strict_overflow_p = true;
1204 if (is_negative_overflow_infinity (val1))
1205 return is_negative_overflow_infinity (val2) ? 0 : -1;
1206 else if (is_negative_overflow_infinity (val2))
1208 else if (is_positive_overflow_infinity (val1))
1209 return is_positive_overflow_infinity (val2) ? 0 : 1;
1210 else if (is_positive_overflow_infinity (val2))
1215 return tree_int_cst_compare (val1, val2);
1221 /* First see if VAL1 and VAL2 are not the same. */
1222 if (val1 == val2 || operand_equal_p (val1, val2, 0))
1225 /* If VAL1 is a lower address than VAL2, return -1. */
1226 if (operand_less_p (val1, val2) == 1)
1229 /* If VAL1 is a higher address than VAL2, return +1. */
1230 if (operand_less_p (val2, val1) == 1)
1233 /* If VAL1 is different than VAL2, return +2.
1234 For integer constants we either have already returned -1 or 1
1235 or they are equivalent. We still might succeed in proving
1236 something about non-trivial operands. */
1237 if (TREE_CODE (val1) != INTEGER_CST
1238 || TREE_CODE (val2) != INTEGER_CST)
1240 t = fold_binary_to_constant (NE_EXPR, boolean_type_node, val1, val2);
1241 if (t && integer_onep (t))
1249 /* Compare values like compare_values_warnv, but treat comparisons of
1250 nonconstants which rely on undefined overflow as incomparable. */
1253 compare_values (tree val1, tree val2)
1259 ret = compare_values_warnv (val1, val2, &sop);
1261 && (!is_gimple_min_invariant (val1) || !is_gimple_min_invariant (val2)))
1267 /* Return 1 if VAL is inside value range VR (VR->MIN <= VAL <= VR->MAX),
1268 0 if VAL is not inside VR,
1269 -2 if we cannot tell either way.
1271 FIXME, the current semantics of this functions are a bit quirky
1272 when taken in the context of VRP. In here we do not care
1273 about VR's type. If VR is the anti-range ~[3, 5] the call
1274 value_inside_range (4, VR) will return 1.
1276 This is counter-intuitive in a strict sense, but the callers
1277 currently expect this. They are calling the function
1278 merely to determine whether VR->MIN <= VAL <= VR->MAX. The
1279 callers are applying the VR_RANGE/VR_ANTI_RANGE semantics
1282 This also applies to value_ranges_intersect_p and
1283 range_includes_zero_p. The semantics of VR_RANGE and
1284 VR_ANTI_RANGE should be encoded here, but that also means
1285 adapting the users of these functions to the new semantics.
1287 Benchmark compile/20001226-1.c compilation time after changing this
1291 value_inside_range (tree val, value_range_t * vr)
1295 cmp1 = operand_less_p (val, vr->min);
1301 cmp2 = operand_less_p (vr->max, val);
1309 /* Return true if value ranges VR0 and VR1 have a non-empty
1312 Benchmark compile/20001226-1.c compilation time after changing this
1317 value_ranges_intersect_p (value_range_t *vr0, value_range_t *vr1)
1319 /* The value ranges do not intersect if the maximum of the first range is
1320 less than the minimum of the second range or vice versa.
1321 When those relations are unknown, we can't do any better. */
1322 if (operand_less_p (vr0->max, vr1->min) != 0)
1324 if (operand_less_p (vr1->max, vr0->min) != 0)
1330 /* Return true if VR includes the value zero, false otherwise. FIXME,
1331 currently this will return false for an anti-range like ~[-4, 3].
1332 This will be wrong when the semantics of value_inside_range are
1333 modified (currently the users of this function expect these
1337 range_includes_zero_p (value_range_t *vr)
1341 gcc_assert (vr->type != VR_UNDEFINED
1342 && vr->type != VR_VARYING
1343 && !symbolic_range_p (vr));
1345 zero = build_int_cst (TREE_TYPE (vr->min), 0);
1346 return (value_inside_range (zero, vr) == 1);
1349 /* Return true if T, an SSA_NAME, is known to be nonnegative. Return
1350 false otherwise or if no value range information is available. */
1353 ssa_name_nonnegative_p (const_tree t)
1355 value_range_t *vr = get_value_range (t);
1360 /* Testing for VR_ANTI_RANGE is not useful here as any anti-range
1361 which would return a useful value should be encoded as a VR_RANGE. */
1362 if (vr->type == VR_RANGE)
1364 int result = compare_values (vr->min, integer_zero_node);
1366 return (result == 0 || result == 1);
1371 /* If OP has a value range with a single constant value return that,
1372 otherwise return NULL_TREE. This returns OP itself if OP is a
1376 op_with_constant_singleton_value_range (tree op)
1380 if (is_gimple_min_invariant (op))
1383 if (TREE_CODE (op) != SSA_NAME)
1386 vr = get_value_range (op);
1387 if (vr->type == VR_RANGE
1388 && operand_equal_p (vr->min, vr->max, 0)
1389 && is_gimple_min_invariant (vr->min))
1396 /* Extract value range information from an ASSERT_EXPR EXPR and store
1400 extract_range_from_assert (value_range_t *vr_p, tree expr)
1402 tree var, cond, limit, min, max, type;
1403 value_range_t *var_vr, *limit_vr;
1404 enum tree_code cond_code;
1406 var = ASSERT_EXPR_VAR (expr);
1407 cond = ASSERT_EXPR_COND (expr);
1409 gcc_assert (COMPARISON_CLASS_P (cond));
1411 /* Find VAR in the ASSERT_EXPR conditional. */
1412 if (var == TREE_OPERAND (cond, 0)
1413 || TREE_CODE (TREE_OPERAND (cond, 0)) == PLUS_EXPR
1414 || TREE_CODE (TREE_OPERAND (cond, 0)) == NOP_EXPR)
1416 /* If the predicate is of the form VAR COMP LIMIT, then we just
1417 take LIMIT from the RHS and use the same comparison code. */
1418 cond_code = TREE_CODE (cond);
1419 limit = TREE_OPERAND (cond, 1);
1420 cond = TREE_OPERAND (cond, 0);
1424 /* If the predicate is of the form LIMIT COMP VAR, then we need
1425 to flip around the comparison code to create the proper range
1427 cond_code = swap_tree_comparison (TREE_CODE (cond));
1428 limit = TREE_OPERAND (cond, 0);
1429 cond = TREE_OPERAND (cond, 1);
1432 limit = avoid_overflow_infinity (limit);
1434 type = TREE_TYPE (limit);
1435 gcc_assert (limit != var);
1437 /* For pointer arithmetic, we only keep track of pointer equality
1439 if (POINTER_TYPE_P (type) && cond_code != NE_EXPR && cond_code != EQ_EXPR)
1441 set_value_range_to_varying (vr_p);
1445 /* If LIMIT is another SSA name and LIMIT has a range of its own,
1446 try to use LIMIT's range to avoid creating symbolic ranges
1448 limit_vr = (TREE_CODE (limit) == SSA_NAME) ? get_value_range (limit) : NULL;
1450 /* LIMIT's range is only interesting if it has any useful information. */
1452 && (limit_vr->type == VR_UNDEFINED
1453 || limit_vr->type == VR_VARYING
1454 || symbolic_range_p (limit_vr)))
1457 /* Initially, the new range has the same set of equivalences of
1458 VAR's range. This will be revised before returning the final
1459 value. Since assertions may be chained via mutually exclusive
1460 predicates, we will need to trim the set of equivalences before
1462 gcc_assert (vr_p->equiv == NULL);
1463 add_equivalence (&vr_p->equiv, var);
1465 /* Extract a new range based on the asserted comparison for VAR and
1466 LIMIT's value range. Notice that if LIMIT has an anti-range, we
1467 will only use it for equality comparisons (EQ_EXPR). For any
1468 other kind of assertion, we cannot derive a range from LIMIT's
1469 anti-range that can be used to describe the new range. For
1470 instance, ASSERT_EXPR <x_2, x_2 <= b_4>. If b_4 is ~[2, 10],
1471 then b_4 takes on the ranges [-INF, 1] and [11, +INF]. There is
1472 no single range for x_2 that could describe LE_EXPR, so we might
1473 as well build the range [b_4, +INF] for it.
1474 One special case we handle is extracting a range from a
1475 range test encoded as (unsigned)var + CST <= limit. */
1476 if (TREE_CODE (cond) == NOP_EXPR
1477 || TREE_CODE (cond) == PLUS_EXPR)
1479 if (TREE_CODE (cond) == PLUS_EXPR)
1481 min = fold_build1 (NEGATE_EXPR, TREE_TYPE (TREE_OPERAND (cond, 1)),
1482 TREE_OPERAND (cond, 1));
1483 max = int_const_binop (PLUS_EXPR, limit, min, 0);
1484 cond = TREE_OPERAND (cond, 0);
1488 min = build_int_cst (TREE_TYPE (var), 0);
1492 /* Make sure to not set TREE_OVERFLOW on the final type
1493 conversion. We are willingly interpreting large positive
1494 unsigned values as negative singed values here. */
1495 min = force_fit_type_double (TREE_TYPE (var), TREE_INT_CST_LOW (min),
1496 TREE_INT_CST_HIGH (min), 0, false);
1497 max = force_fit_type_double (TREE_TYPE (var), TREE_INT_CST_LOW (max),
1498 TREE_INT_CST_HIGH (max), 0, false);
1500 /* We can transform a max, min range to an anti-range or
1501 vice-versa. Use set_and_canonicalize_value_range which does
1503 if (cond_code == LE_EXPR)
1504 set_and_canonicalize_value_range (vr_p, VR_RANGE,
1505 min, max, vr_p->equiv);
1506 else if (cond_code == GT_EXPR)
1507 set_and_canonicalize_value_range (vr_p, VR_ANTI_RANGE,
1508 min, max, vr_p->equiv);
1512 else if (cond_code == EQ_EXPR)
1514 enum value_range_type range_type;
1518 range_type = limit_vr->type;
1519 min = limit_vr->min;
1520 max = limit_vr->max;
1524 range_type = VR_RANGE;
1529 set_value_range (vr_p, range_type, min, max, vr_p->equiv);
1531 /* When asserting the equality VAR == LIMIT and LIMIT is another
1532 SSA name, the new range will also inherit the equivalence set
1534 if (TREE_CODE (limit) == SSA_NAME)
1535 add_equivalence (&vr_p->equiv, limit);
1537 else if (cond_code == NE_EXPR)
1539 /* As described above, when LIMIT's range is an anti-range and
1540 this assertion is an inequality (NE_EXPR), then we cannot
1541 derive anything from the anti-range. For instance, if
1542 LIMIT's range was ~[0, 0], the assertion 'VAR != LIMIT' does
1543 not imply that VAR's range is [0, 0]. So, in the case of
1544 anti-ranges, we just assert the inequality using LIMIT and
1547 If LIMIT_VR is a range, we can only use it to build a new
1548 anti-range if LIMIT_VR is a single-valued range. For
1549 instance, if LIMIT_VR is [0, 1], the predicate
1550 VAR != [0, 1] does not mean that VAR's range is ~[0, 1].
1551 Rather, it means that for value 0 VAR should be ~[0, 0]
1552 and for value 1, VAR should be ~[1, 1]. We cannot
1553 represent these ranges.
1555 The only situation in which we can build a valid
1556 anti-range is when LIMIT_VR is a single-valued range
1557 (i.e., LIMIT_VR->MIN == LIMIT_VR->MAX). In that case,
1558 build the anti-range ~[LIMIT_VR->MIN, LIMIT_VR->MAX]. */
1560 && limit_vr->type == VR_RANGE
1561 && compare_values (limit_vr->min, limit_vr->max) == 0)
1563 min = limit_vr->min;
1564 max = limit_vr->max;
1568 /* In any other case, we cannot use LIMIT's range to build a
1569 valid anti-range. */
1573 /* If MIN and MAX cover the whole range for their type, then
1574 just use the original LIMIT. */
1575 if (INTEGRAL_TYPE_P (type)
1576 && vrp_val_is_min (min)
1577 && vrp_val_is_max (max))
1580 set_value_range (vr_p, VR_ANTI_RANGE, min, max, vr_p->equiv);
1582 else if (cond_code == LE_EXPR || cond_code == LT_EXPR)
1584 min = TYPE_MIN_VALUE (type);
1586 if (limit_vr == NULL || limit_vr->type == VR_ANTI_RANGE)
1590 /* If LIMIT_VR is of the form [N1, N2], we need to build the
1591 range [MIN, N2] for LE_EXPR and [MIN, N2 - 1] for
1593 max = limit_vr->max;
1596 /* If the maximum value forces us to be out of bounds, simply punt.
1597 It would be pointless to try and do anything more since this
1598 all should be optimized away above us. */
1599 if ((cond_code == LT_EXPR
1600 && compare_values (max, min) == 0)
1601 || (CONSTANT_CLASS_P (max) && TREE_OVERFLOW (max)))
1602 set_value_range_to_varying (vr_p);
1605 /* For LT_EXPR, we create the range [MIN, MAX - 1]. */
1606 if (cond_code == LT_EXPR)
1608 tree one = build_int_cst (type, 1);
1609 max = fold_build2 (MINUS_EXPR, type, max, one);
1611 TREE_NO_WARNING (max) = 1;
1614 set_value_range (vr_p, VR_RANGE, min, max, vr_p->equiv);
1617 else if (cond_code == GE_EXPR || cond_code == GT_EXPR)
1619 max = TYPE_MAX_VALUE (type);
1621 if (limit_vr == NULL || limit_vr->type == VR_ANTI_RANGE)
1625 /* If LIMIT_VR is of the form [N1, N2], we need to build the
1626 range [N1, MAX] for GE_EXPR and [N1 + 1, MAX] for
1628 min = limit_vr->min;
1631 /* If the minimum value forces us to be out of bounds, simply punt.
1632 It would be pointless to try and do anything more since this
1633 all should be optimized away above us. */
1634 if ((cond_code == GT_EXPR
1635 && compare_values (min, max) == 0)
1636 || (CONSTANT_CLASS_P (min) && TREE_OVERFLOW (min)))
1637 set_value_range_to_varying (vr_p);
1640 /* For GT_EXPR, we create the range [MIN + 1, MAX]. */
1641 if (cond_code == GT_EXPR)
1643 tree one = build_int_cst (type, 1);
1644 min = fold_build2 (PLUS_EXPR, type, min, one);
1646 TREE_NO_WARNING (min) = 1;
1649 set_value_range (vr_p, VR_RANGE, min, max, vr_p->equiv);
1655 /* If VAR already had a known range, it may happen that the new
1656 range we have computed and VAR's range are not compatible. For
1660 p_6 = ASSERT_EXPR <p_5, p_5 == NULL>;
1662 p_8 = ASSERT_EXPR <p_6, p_6 != NULL>;
1664 While the above comes from a faulty program, it will cause an ICE
1665 later because p_8 and p_6 will have incompatible ranges and at
1666 the same time will be considered equivalent. A similar situation
1670 i_6 = ASSERT_EXPR <i_5, i_5 > 10>;
1672 i_7 = ASSERT_EXPR <i_6, i_6 < 5>;
1674 Again i_6 and i_7 will have incompatible ranges. It would be
1675 pointless to try and do anything with i_7's range because
1676 anything dominated by 'if (i_5 < 5)' will be optimized away.
1677 Note, due to the wa in which simulation proceeds, the statement
1678 i_7 = ASSERT_EXPR <...> we would never be visited because the
1679 conditional 'if (i_5 < 5)' always evaluates to false. However,
1680 this extra check does not hurt and may protect against future
1681 changes to VRP that may get into a situation similar to the
1682 NULL pointer dereference example.
1684 Note that these compatibility tests are only needed when dealing
1685 with ranges or a mix of range and anti-range. If VAR_VR and VR_P
1686 are both anti-ranges, they will always be compatible, because two
1687 anti-ranges will always have a non-empty intersection. */
1689 var_vr = get_value_range (var);
1691 /* We may need to make adjustments when VR_P and VAR_VR are numeric
1692 ranges or anti-ranges. */
1693 if (vr_p->type == VR_VARYING
1694 || vr_p->type == VR_UNDEFINED
1695 || var_vr->type == VR_VARYING
1696 || var_vr->type == VR_UNDEFINED
1697 || symbolic_range_p (vr_p)
1698 || symbolic_range_p (var_vr))
1701 if (var_vr->type == VR_RANGE && vr_p->type == VR_RANGE)
1703 /* If the two ranges have a non-empty intersection, we can
1704 refine the resulting range. Since the assert expression
1705 creates an equivalency and at the same time it asserts a
1706 predicate, we can take the intersection of the two ranges to
1707 get better precision. */
1708 if (value_ranges_intersect_p (var_vr, vr_p))
1710 /* Use the larger of the two minimums. */
1711 if (compare_values (vr_p->min, var_vr->min) == -1)
1716 /* Use the smaller of the two maximums. */
1717 if (compare_values (vr_p->max, var_vr->max) == 1)
1722 set_value_range (vr_p, vr_p->type, min, max, vr_p->equiv);
1726 /* The two ranges do not intersect, set the new range to
1727 VARYING, because we will not be able to do anything
1728 meaningful with it. */
1729 set_value_range_to_varying (vr_p);
1732 else if ((var_vr->type == VR_RANGE && vr_p->type == VR_ANTI_RANGE)
1733 || (var_vr->type == VR_ANTI_RANGE && vr_p->type == VR_RANGE))
1735 /* A range and an anti-range will cancel each other only if
1736 their ends are the same. For instance, in the example above,
1737 p_8's range ~[0, 0] and p_6's range [0, 0] are incompatible,
1738 so VR_P should be set to VR_VARYING. */
1739 if (compare_values (var_vr->min, vr_p->min) == 0
1740 && compare_values (var_vr->max, vr_p->max) == 0)
1741 set_value_range_to_varying (vr_p);
1744 tree min, max, anti_min, anti_max, real_min, real_max;
1747 /* We want to compute the logical AND of the two ranges;
1748 there are three cases to consider.
1751 1. The VR_ANTI_RANGE range is completely within the
1752 VR_RANGE and the endpoints of the ranges are
1753 different. In that case the resulting range
1754 should be whichever range is more precise.
1755 Typically that will be the VR_RANGE.
1757 2. The VR_ANTI_RANGE is completely disjoint from
1758 the VR_RANGE. In this case the resulting range
1759 should be the VR_RANGE.
1761 3. There is some overlap between the VR_ANTI_RANGE
1764 3a. If the high limit of the VR_ANTI_RANGE resides
1765 within the VR_RANGE, then the result is a new
1766 VR_RANGE starting at the high limit of the
1767 VR_ANTI_RANGE + 1 and extending to the
1768 high limit of the original VR_RANGE.
1770 3b. If the low limit of the VR_ANTI_RANGE resides
1771 within the VR_RANGE, then the result is a new
1772 VR_RANGE starting at the low limit of the original
1773 VR_RANGE and extending to the low limit of the
1774 VR_ANTI_RANGE - 1. */
1775 if (vr_p->type == VR_ANTI_RANGE)
1777 anti_min = vr_p->min;
1778 anti_max = vr_p->max;
1779 real_min = var_vr->min;
1780 real_max = var_vr->max;
1784 anti_min = var_vr->min;
1785 anti_max = var_vr->max;
1786 real_min = vr_p->min;
1787 real_max = vr_p->max;
1791 /* Case 1, VR_ANTI_RANGE completely within VR_RANGE,
1792 not including any endpoints. */
1793 if (compare_values (anti_max, real_max) == -1
1794 && compare_values (anti_min, real_min) == 1)
1796 /* If the range is covering the whole valid range of
1797 the type keep the anti-range. */
1798 if (!vrp_val_is_min (real_min)
1799 || !vrp_val_is_max (real_max))
1800 set_value_range (vr_p, VR_RANGE, real_min,
1801 real_max, vr_p->equiv);
1803 /* Case 2, VR_ANTI_RANGE completely disjoint from
1805 else if (compare_values (anti_min, real_max) == 1
1806 || compare_values (anti_max, real_min) == -1)
1808 set_value_range (vr_p, VR_RANGE, real_min,
1809 real_max, vr_p->equiv);
1811 /* Case 3a, the anti-range extends into the low
1812 part of the real range. Thus creating a new
1813 low for the real range. */
1814 else if (((cmp = compare_values (anti_max, real_min)) == 1
1816 && compare_values (anti_max, real_max) == -1)
1818 gcc_assert (!is_positive_overflow_infinity (anti_max));
1819 if (needs_overflow_infinity (TREE_TYPE (anti_max))
1820 && vrp_val_is_max (anti_max))
1822 if (!supports_overflow_infinity (TREE_TYPE (var_vr->min)))
1824 set_value_range_to_varying (vr_p);
1827 min = positive_overflow_infinity (TREE_TYPE (var_vr->min));
1829 else if (!POINTER_TYPE_P (TREE_TYPE (var_vr->min)))
1830 min = fold_build2 (PLUS_EXPR, TREE_TYPE (var_vr->min),
1832 build_int_cst (TREE_TYPE (var_vr->min), 1));
1834 min = fold_build2 (POINTER_PLUS_EXPR, TREE_TYPE (var_vr->min),
1835 anti_max, size_int (1));
1837 set_value_range (vr_p, VR_RANGE, min, max, vr_p->equiv);
1839 /* Case 3b, the anti-range extends into the high
1840 part of the real range. Thus creating a new
1841 higher for the real range. */
1842 else if (compare_values (anti_min, real_min) == 1
1843 && ((cmp = compare_values (anti_min, real_max)) == -1
1846 gcc_assert (!is_negative_overflow_infinity (anti_min));
1847 if (needs_overflow_infinity (TREE_TYPE (anti_min))
1848 && vrp_val_is_min (anti_min))
1850 if (!supports_overflow_infinity (TREE_TYPE (var_vr->min)))
1852 set_value_range_to_varying (vr_p);
1855 max = negative_overflow_infinity (TREE_TYPE (var_vr->min));
1857 else if (!POINTER_TYPE_P (TREE_TYPE (var_vr->min)))
1858 max = fold_build2 (MINUS_EXPR, TREE_TYPE (var_vr->min),
1860 build_int_cst (TREE_TYPE (var_vr->min), 1));
1862 max = fold_build2 (POINTER_PLUS_EXPR, TREE_TYPE (var_vr->min),
1866 set_value_range (vr_p, VR_RANGE, min, max, vr_p->equiv);
1873 /* Extract range information from SSA name VAR and store it in VR. If
1874 VAR has an interesting range, use it. Otherwise, create the
1875 range [VAR, VAR] and return it. This is useful in situations where
1876 we may have conditionals testing values of VARYING names. For
1883 Even if y_5 is deemed VARYING, we can determine that x_3 > y_5 is
1887 extract_range_from_ssa_name (value_range_t *vr, tree var)
1889 value_range_t *var_vr = get_value_range (var);
1891 if (var_vr->type != VR_UNDEFINED && var_vr->type != VR_VARYING)
1892 copy_value_range (vr, var_vr);
1894 set_value_range (vr, VR_RANGE, var, var, NULL);
1896 add_equivalence (&vr->equiv, var);
1900 /* Wrapper around int_const_binop. If the operation overflows and we
1901 are not using wrapping arithmetic, then adjust the result to be
1902 -INF or +INF depending on CODE, VAL1 and VAL2. This can return
1903 NULL_TREE if we need to use an overflow infinity representation but
1904 the type does not support it. */
1907 vrp_int_const_binop (enum tree_code code, tree val1, tree val2)
1911 res = int_const_binop (code, val1, val2, 0);
1913 /* If we are not using wrapping arithmetic, operate symbolically
1914 on -INF and +INF. */
1915 if (TYPE_OVERFLOW_WRAPS (TREE_TYPE (val1)))
1917 int checkz = compare_values (res, val1);
1918 bool overflow = false;
1920 /* Ensure that res = val1 [+*] val2 >= val1
1921 or that res = val1 - val2 <= val1. */
1922 if ((code == PLUS_EXPR
1923 && !(checkz == 1 || checkz == 0))
1924 || (code == MINUS_EXPR
1925 && !(checkz == 0 || checkz == -1)))
1929 /* Checking for multiplication overflow is done by dividing the
1930 output of the multiplication by the first input of the
1931 multiplication. If the result of that division operation is
1932 not equal to the second input of the multiplication, then the
1933 multiplication overflowed. */
1934 else if (code == MULT_EXPR && !integer_zerop (val1))
1936 tree tmp = int_const_binop (TRUNC_DIV_EXPR,
1939 int check = compare_values (tmp, val2);
1947 res = copy_node (res);
1948 TREE_OVERFLOW (res) = 1;
1952 else if ((TREE_OVERFLOW (res)
1953 && !TREE_OVERFLOW (val1)
1954 && !TREE_OVERFLOW (val2))
1955 || is_overflow_infinity (val1)
1956 || is_overflow_infinity (val2))
1958 /* If the operation overflowed but neither VAL1 nor VAL2 are
1959 overflown, return -INF or +INF depending on the operation
1960 and the combination of signs of the operands. */
1961 int sgn1 = tree_int_cst_sgn (val1);
1962 int sgn2 = tree_int_cst_sgn (val2);
1964 if (needs_overflow_infinity (TREE_TYPE (res))
1965 && !supports_overflow_infinity (TREE_TYPE (res)))
1968 /* We have to punt on adding infinities of different signs,
1969 since we can't tell what the sign of the result should be.
1970 Likewise for subtracting infinities of the same sign. */
1971 if (((code == PLUS_EXPR && sgn1 != sgn2)
1972 || (code == MINUS_EXPR && sgn1 == sgn2))
1973 && is_overflow_infinity (val1)
1974 && is_overflow_infinity (val2))
1977 /* Don't try to handle division or shifting of infinities. */
1978 if ((code == TRUNC_DIV_EXPR
1979 || code == FLOOR_DIV_EXPR
1980 || code == CEIL_DIV_EXPR
1981 || code == EXACT_DIV_EXPR
1982 || code == ROUND_DIV_EXPR
1983 || code == RSHIFT_EXPR)
1984 && (is_overflow_infinity (val1)
1985 || is_overflow_infinity (val2)))
1988 /* Notice that we only need to handle the restricted set of
1989 operations handled by extract_range_from_binary_expr.
1990 Among them, only multiplication, addition and subtraction
1991 can yield overflow without overflown operands because we
1992 are working with integral types only... except in the
1993 case VAL1 = -INF and VAL2 = -1 which overflows to +INF
1994 for division too. */
1996 /* For multiplication, the sign of the overflow is given
1997 by the comparison of the signs of the operands. */
1998 if ((code == MULT_EXPR && sgn1 == sgn2)
1999 /* For addition, the operands must be of the same sign
2000 to yield an overflow. Its sign is therefore that
2001 of one of the operands, for example the first. For
2002 infinite operands X + -INF is negative, not positive. */
2003 || (code == PLUS_EXPR
2005 ? !is_negative_overflow_infinity (val2)
2006 : is_positive_overflow_infinity (val2)))
2007 /* For subtraction, non-infinite operands must be of
2008 different signs to yield an overflow. Its sign is
2009 therefore that of the first operand or the opposite of
2010 that of the second operand. A first operand of 0 counts
2011 as positive here, for the corner case 0 - (-INF), which
2012 overflows, but must yield +INF. For infinite operands 0
2013 - INF is negative, not positive. */
2014 || (code == MINUS_EXPR
2016 ? !is_positive_overflow_infinity (val2)
2017 : is_negative_overflow_infinity (val2)))
2018 /* We only get in here with positive shift count, so the
2019 overflow direction is the same as the sign of val1.
2020 Actually rshift does not overflow at all, but we only
2021 handle the case of shifting overflowed -INF and +INF. */
2022 || (code == RSHIFT_EXPR
2024 /* For division, the only case is -INF / -1 = +INF. */
2025 || code == TRUNC_DIV_EXPR
2026 || code == FLOOR_DIV_EXPR
2027 || code == CEIL_DIV_EXPR
2028 || code == EXACT_DIV_EXPR
2029 || code == ROUND_DIV_EXPR)
2030 return (needs_overflow_infinity (TREE_TYPE (res))
2031 ? positive_overflow_infinity (TREE_TYPE (res))
2032 : TYPE_MAX_VALUE (TREE_TYPE (res)));
2034 return (needs_overflow_infinity (TREE_TYPE (res))
2035 ? negative_overflow_infinity (TREE_TYPE (res))
2036 : TYPE_MIN_VALUE (TREE_TYPE (res)));
2043 /* Extract range information from a binary expression EXPR based on
2044 the ranges of each of its operands and the expression code. */
2047 extract_range_from_binary_expr (value_range_t *vr,
2048 enum tree_code code,
2049 tree expr_type, tree op0, tree op1)
2051 enum value_range_type type;
2054 value_range_t vr0 = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
2055 value_range_t vr1 = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
2057 /* Not all binary expressions can be applied to ranges in a
2058 meaningful way. Handle only arithmetic operations. */
2059 if (code != PLUS_EXPR
2060 && code != MINUS_EXPR
2061 && code != POINTER_PLUS_EXPR
2062 && code != MULT_EXPR
2063 && code != TRUNC_DIV_EXPR
2064 && code != FLOOR_DIV_EXPR
2065 && code != CEIL_DIV_EXPR
2066 && code != EXACT_DIV_EXPR
2067 && code != ROUND_DIV_EXPR
2068 && code != RSHIFT_EXPR
2071 && code != BIT_AND_EXPR
2072 && code != BIT_IOR_EXPR
2073 && code != TRUTH_AND_EXPR
2074 && code != TRUTH_OR_EXPR)
2076 /* We can still do constant propagation here. */
2077 tree const_op0 = op_with_constant_singleton_value_range (op0);
2078 tree const_op1 = op_with_constant_singleton_value_range (op1);
2079 if (const_op0 || const_op1)
2081 tree tem = fold_binary (code, expr_type,
2082 const_op0 ? const_op0 : op0,
2083 const_op1 ? const_op1 : op1);
2085 && is_gimple_min_invariant (tem)
2086 && !is_overflow_infinity (tem))
2088 set_value_range (vr, VR_RANGE, tem, tem, NULL);
2092 set_value_range_to_varying (vr);
2096 /* Get value ranges for each operand. For constant operands, create
2097 a new value range with the operand to simplify processing. */
2098 if (TREE_CODE (op0) == SSA_NAME)
2099 vr0 = *(get_value_range (op0));
2100 else if (is_gimple_min_invariant (op0))
2101 set_value_range_to_value (&vr0, op0, NULL);
2103 set_value_range_to_varying (&vr0);
2105 if (TREE_CODE (op1) == SSA_NAME)
2106 vr1 = *(get_value_range (op1));
2107 else if (is_gimple_min_invariant (op1))
2108 set_value_range_to_value (&vr1, op1, NULL);
2110 set_value_range_to_varying (&vr1);
2112 /* If either range is UNDEFINED, so is the result. */
2113 if (vr0.type == VR_UNDEFINED || vr1.type == VR_UNDEFINED)
2115 set_value_range_to_undefined (vr);
2119 /* The type of the resulting value range defaults to VR0.TYPE. */
2122 /* Refuse to operate on VARYING ranges, ranges of different kinds
2123 and symbolic ranges. As an exception, we allow BIT_AND_EXPR
2124 because we may be able to derive a useful range even if one of
2125 the operands is VR_VARYING or symbolic range. Similarly for
2126 divisions. TODO, we may be able to derive anti-ranges in
2128 if (code != BIT_AND_EXPR
2129 && code != TRUTH_AND_EXPR
2130 && code != TRUTH_OR_EXPR
2131 && code != TRUNC_DIV_EXPR
2132 && code != FLOOR_DIV_EXPR
2133 && code != CEIL_DIV_EXPR
2134 && code != EXACT_DIV_EXPR
2135 && code != ROUND_DIV_EXPR
2136 && (vr0.type == VR_VARYING
2137 || vr1.type == VR_VARYING
2138 || vr0.type != vr1.type
2139 || symbolic_range_p (&vr0)
2140 || symbolic_range_p (&vr1)))
2142 set_value_range_to_varying (vr);
2146 /* Now evaluate the expression to determine the new range. */
2147 if (POINTER_TYPE_P (expr_type)
2148 || POINTER_TYPE_P (TREE_TYPE (op0))
2149 || POINTER_TYPE_P (TREE_TYPE (op1)))
2151 if (code == MIN_EXPR || code == MAX_EXPR)
2153 /* For MIN/MAX expressions with pointers, we only care about
2154 nullness, if both are non null, then the result is nonnull.
2155 If both are null, then the result is null. Otherwise they
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);
2166 gcc_assert (code == POINTER_PLUS_EXPR);
2167 /* For pointer types, we are really only interested in asserting
2168 whether the expression evaluates to non-NULL. */
2169 if (range_is_nonnull (&vr0) || range_is_nonnull (&vr1))
2170 set_value_range_to_nonnull (vr, expr_type);
2171 else if (range_is_null (&vr0) && range_is_null (&vr1))
2172 set_value_range_to_null (vr, expr_type);
2174 set_value_range_to_varying (vr);
2179 /* For integer ranges, apply the operation to each end of the
2180 range and see what we end up with. */
2181 if (code == TRUTH_AND_EXPR
2182 || code == TRUTH_OR_EXPR)
2184 /* If one of the operands is zero, we know that the whole
2185 expression evaluates zero. */
2186 if (code == TRUTH_AND_EXPR
2187 && ((vr0.type == VR_RANGE
2188 && integer_zerop (vr0.min)
2189 && integer_zerop (vr0.max))
2190 || (vr1.type == VR_RANGE
2191 && integer_zerop (vr1.min)
2192 && integer_zerop (vr1.max))))
2195 min = max = build_int_cst (expr_type, 0);
2197 /* If one of the operands is one, we know that the whole
2198 expression evaluates one. */
2199 else if (code == TRUTH_OR_EXPR
2200 && ((vr0.type == VR_RANGE
2201 && integer_onep (vr0.min)
2202 && integer_onep (vr0.max))
2203 || (vr1.type == VR_RANGE
2204 && integer_onep (vr1.min)
2205 && integer_onep (vr1.max))))
2208 min = max = build_int_cst (expr_type, 1);
2210 else if (vr0.type != VR_VARYING
2211 && vr1.type != VR_VARYING
2212 && vr0.type == vr1.type
2213 && !symbolic_range_p (&vr0)
2214 && !overflow_infinity_range_p (&vr0)
2215 && !symbolic_range_p (&vr1)
2216 && !overflow_infinity_range_p (&vr1))
2218 /* Boolean expressions cannot be folded with int_const_binop. */
2219 min = fold_binary (code, expr_type, vr0.min, vr1.min);
2220 max = fold_binary (code, expr_type, vr0.max, vr1.max);
2224 /* The result of a TRUTH_*_EXPR is always true or false. */
2225 set_value_range_to_truthvalue (vr, expr_type);
2229 else if (code == PLUS_EXPR
2231 || code == MAX_EXPR)
2233 /* If we have a PLUS_EXPR with two VR_ANTI_RANGEs, drop to
2234 VR_VARYING. It would take more effort to compute a precise
2235 range for such a case. For example, if we have op0 == 1 and
2236 op1 == -1 with their ranges both being ~[0,0], we would have
2237 op0 + op1 == 0, so we cannot claim that the sum is in ~[0,0].
2238 Note that we are guaranteed to have vr0.type == vr1.type at
2240 if (code == PLUS_EXPR && vr0.type == VR_ANTI_RANGE)
2242 set_value_range_to_varying (vr);
2246 /* For operations that make the resulting range directly
2247 proportional to the original ranges, apply the operation to
2248 the same end of each range. */
2249 min = vrp_int_const_binop (code, vr0.min, vr1.min);
2250 max = vrp_int_const_binop (code, vr0.max, vr1.max);
2252 /* If both additions overflowed the range kind is still correct.
2253 This happens regularly with subtracting something in unsigned
2255 ??? See PR30318 for all the cases we do not handle. */
2256 if (code == PLUS_EXPR
2257 && (TREE_OVERFLOW (min) && !is_overflow_infinity (min))
2258 && (TREE_OVERFLOW (max) && !is_overflow_infinity (max)))
2260 min = build_int_cst_wide (TREE_TYPE (min),
2261 TREE_INT_CST_LOW (min),
2262 TREE_INT_CST_HIGH (min));
2263 max = build_int_cst_wide (TREE_TYPE (max),
2264 TREE_INT_CST_LOW (max),
2265 TREE_INT_CST_HIGH (max));
2268 else if (code == MULT_EXPR
2269 || code == TRUNC_DIV_EXPR
2270 || code == FLOOR_DIV_EXPR
2271 || code == CEIL_DIV_EXPR
2272 || code == EXACT_DIV_EXPR
2273 || code == ROUND_DIV_EXPR
2274 || code == RSHIFT_EXPR)
2280 /* If we have an unsigned MULT_EXPR with two VR_ANTI_RANGEs,
2281 drop to VR_VARYING. It would take more effort to compute a
2282 precise range for such a case. For example, if we have
2283 op0 == 65536 and op1 == 65536 with their ranges both being
2284 ~[0,0] on a 32-bit machine, we would have op0 * op1 == 0, so
2285 we cannot claim that the product is in ~[0,0]. Note that we
2286 are guaranteed to have vr0.type == vr1.type at this
2288 if (code == MULT_EXPR
2289 && vr0.type == VR_ANTI_RANGE
2290 && !TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (op0)))
2292 set_value_range_to_varying (vr);
2296 /* If we have a RSHIFT_EXPR with any shift values outside [0..prec-1],
2297 then drop to VR_VARYING. Outside of this range we get undefined
2298 behavior from the shift operation. We cannot even trust
2299 SHIFT_COUNT_TRUNCATED at this stage, because that applies to rtl
2300 shifts, and the operation at the tree level may be widened. */
2301 if (code == RSHIFT_EXPR)
2303 if (vr1.type == VR_ANTI_RANGE
2304 || !vrp_expr_computes_nonnegative (op1, &sop)
2306 (build_int_cst (TREE_TYPE (vr1.max),
2307 TYPE_PRECISION (expr_type) - 1),
2310 set_value_range_to_varying (vr);
2315 else if ((code == TRUNC_DIV_EXPR
2316 || code == FLOOR_DIV_EXPR
2317 || code == CEIL_DIV_EXPR
2318 || code == EXACT_DIV_EXPR
2319 || code == ROUND_DIV_EXPR)
2320 && (vr0.type != VR_RANGE || symbolic_range_p (&vr0)))
2322 /* For division, if op1 has VR_RANGE but op0 does not, something
2323 can be deduced just from that range. Say [min, max] / [4, max]
2324 gives [min / 4, max / 4] range. */
2325 if (vr1.type == VR_RANGE
2326 && !symbolic_range_p (&vr1)
2327 && !range_includes_zero_p (&vr1))
2329 vr0.type = type = VR_RANGE;
2330 vr0.min = vrp_val_min (TREE_TYPE (op0));
2331 vr0.max = vrp_val_max (TREE_TYPE (op1));
2335 set_value_range_to_varying (vr);
2340 /* For divisions, if op0 is VR_RANGE, we can deduce a range
2341 even if op1 is VR_VARYING, VR_ANTI_RANGE, symbolic or can
2343 if ((code == TRUNC_DIV_EXPR
2344 || code == FLOOR_DIV_EXPR
2345 || code == CEIL_DIV_EXPR
2346 || code == EXACT_DIV_EXPR
2347 || code == ROUND_DIV_EXPR)
2348 && vr0.type == VR_RANGE
2349 && (vr1.type != VR_RANGE
2350 || symbolic_range_p (&vr1)
2351 || range_includes_zero_p (&vr1)))
2353 tree zero = build_int_cst (TREE_TYPE (vr0.min), 0);
2359 if (vrp_expr_computes_nonnegative (op1, &sop) && !sop)
2361 /* For unsigned division or when divisor is known
2362 to be non-negative, the range has to cover
2363 all numbers from 0 to max for positive max
2364 and all numbers from min to 0 for negative min. */
2365 cmp = compare_values (vr0.max, zero);
2368 else if (cmp == 0 || cmp == 1)
2372 cmp = compare_values (vr0.min, zero);
2375 else if (cmp == 0 || cmp == -1)
2382 /* Otherwise the range is -max .. max or min .. -min
2383 depending on which bound is bigger in absolute value,
2384 as the division can change the sign. */
2385 abs_extent_range (vr, vr0.min, vr0.max);
2388 if (type == VR_VARYING)
2390 set_value_range_to_varying (vr);
2395 /* Multiplications and divisions are a bit tricky to handle,
2396 depending on the mix of signs we have in the two ranges, we
2397 need to operate on different values to get the minimum and
2398 maximum values for the new range. One approach is to figure
2399 out all the variations of range combinations and do the
2402 However, this involves several calls to compare_values and it
2403 is pretty convoluted. It's simpler to do the 4 operations
2404 (MIN0 OP MIN1, MIN0 OP MAX1, MAX0 OP MIN1 and MAX0 OP MAX0 OP
2405 MAX1) and then figure the smallest and largest values to form
2409 gcc_assert ((vr0.type == VR_RANGE
2410 || (code == MULT_EXPR && vr0.type == VR_ANTI_RANGE))
2411 && vr0.type == vr1.type);
2413 /* Compute the 4 cross operations. */
2415 val[0] = vrp_int_const_binop (code, vr0.min, vr1.min);
2416 if (val[0] == NULL_TREE)
2419 if (vr1.max == vr1.min)
2423 val[1] = vrp_int_const_binop (code, vr0.min, vr1.max);
2424 if (val[1] == NULL_TREE)
2428 if (vr0.max == vr0.min)
2432 val[2] = vrp_int_const_binop (code, vr0.max, vr1.min);
2433 if (val[2] == NULL_TREE)
2437 if (vr0.min == vr0.max || vr1.min == vr1.max)
2441 val[3] = vrp_int_const_binop (code, vr0.max, vr1.max);
2442 if (val[3] == NULL_TREE)
2448 set_value_range_to_varying (vr);
2452 /* Set MIN to the minimum of VAL[i] and MAX to the maximum
2456 for (i = 1; i < 4; i++)
2458 if (!is_gimple_min_invariant (min)
2459 || (TREE_OVERFLOW (min) && !is_overflow_infinity (min))
2460 || !is_gimple_min_invariant (max)
2461 || (TREE_OVERFLOW (max) && !is_overflow_infinity (max)))
2466 if (!is_gimple_min_invariant (val[i])
2467 || (TREE_OVERFLOW (val[i])
2468 && !is_overflow_infinity (val[i])))
2470 /* If we found an overflowed value, set MIN and MAX
2471 to it so that we set the resulting range to
2477 if (compare_values (val[i], min) == -1)
2480 if (compare_values (val[i], max) == 1)
2486 else if (code == MINUS_EXPR)
2488 /* If we have a MINUS_EXPR with two VR_ANTI_RANGEs, drop to
2489 VR_VARYING. It would take more effort to compute a precise
2490 range for such a case. For example, if we have op0 == 1 and
2491 op1 == 1 with their ranges both being ~[0,0], we would have
2492 op0 - op1 == 0, so we cannot claim that the difference is in
2493 ~[0,0]. Note that we are guaranteed to have
2494 vr0.type == vr1.type at this point. */
2495 if (vr0.type == VR_ANTI_RANGE)
2497 set_value_range_to_varying (vr);
2501 /* For MINUS_EXPR, apply the operation to the opposite ends of
2503 min = vrp_int_const_binop (code, vr0.min, vr1.max);
2504 max = vrp_int_const_binop (code, vr0.max, vr1.min);
2506 else if (code == BIT_AND_EXPR)
2508 if (vr0.type == VR_RANGE
2509 && vr0.min == vr0.max
2510 && TREE_CODE (vr0.max) == INTEGER_CST
2511 && !TREE_OVERFLOW (vr0.max)
2512 && tree_int_cst_sgn (vr0.max) >= 0)
2514 min = build_int_cst (expr_type, 0);
2517 else if (vr1.type == VR_RANGE
2518 && vr1.min == vr1.max
2519 && TREE_CODE (vr1.max) == INTEGER_CST
2520 && !TREE_OVERFLOW (vr1.max)
2521 && tree_int_cst_sgn (vr1.max) >= 0)
2524 min = build_int_cst (expr_type, 0);
2529 set_value_range_to_varying (vr);
2533 else if (code == BIT_IOR_EXPR)
2535 if (vr0.type == VR_RANGE
2536 && vr1.type == VR_RANGE
2537 && TREE_CODE (vr0.min) == INTEGER_CST
2538 && TREE_CODE (vr1.min) == INTEGER_CST
2539 && TREE_CODE (vr0.max) == INTEGER_CST
2540 && TREE_CODE (vr1.max) == INTEGER_CST
2541 && tree_int_cst_sgn (vr0.min) >= 0
2542 && tree_int_cst_sgn (vr1.min) >= 0)
2544 double_int vr0_max = tree_to_double_int (vr0.max);
2545 double_int vr1_max = tree_to_double_int (vr1.max);
2548 /* Set all bits to the right of the most significant one to 1.
2549 For example, [0, 4] | [4, 4] = [4, 7]. */
2550 ior_max.low = vr0_max.low | vr1_max.low;
2551 ior_max.high = vr0_max.high | vr1_max.high;
2552 if (ior_max.high != 0)
2554 ior_max.low = ~(unsigned HOST_WIDE_INT)0u;
2555 ior_max.high |= ((HOST_WIDE_INT) 1
2556 << floor_log2 (ior_max.high)) - 1;
2558 else if (ior_max.low != 0)
2559 ior_max.low |= ((unsigned HOST_WIDE_INT) 1u
2560 << floor_log2 (ior_max.low)) - 1;
2562 /* Both of these endpoints are conservative. */
2563 min = vrp_int_const_binop (MAX_EXPR, vr0.min, vr1.min);
2564 max = double_int_to_tree (expr_type, ior_max);
2568 set_value_range_to_varying (vr);
2575 /* If either MIN or MAX overflowed, then set the resulting range to
2576 VARYING. But we do accept an overflow infinity
2578 if (min == NULL_TREE
2579 || !is_gimple_min_invariant (min)
2580 || (TREE_OVERFLOW (min) && !is_overflow_infinity (min))
2582 || !is_gimple_min_invariant (max)
2583 || (TREE_OVERFLOW (max) && !is_overflow_infinity (max)))
2585 set_value_range_to_varying (vr);
2591 2) [-INF, +-INF(OVF)]
2592 3) [+-INF(OVF), +INF]
2593 4) [+-INF(OVF), +-INF(OVF)]
2594 We learn nothing when we have INF and INF(OVF) on both sides.
2595 Note that we do accept [-INF, -INF] and [+INF, +INF] without
2597 if ((vrp_val_is_min (min) || is_overflow_infinity (min))
2598 && (vrp_val_is_max (max) || is_overflow_infinity (max)))
2600 set_value_range_to_varying (vr);
2604 cmp = compare_values (min, max);
2605 if (cmp == -2 || cmp == 1)
2607 /* If the new range has its limits swapped around (MIN > MAX),
2608 then the operation caused one of them to wrap around, mark
2609 the new range VARYING. */
2610 set_value_range_to_varying (vr);
2613 set_value_range (vr, type, min, max, NULL);
2617 /* Extract range information from a unary expression EXPR based on
2618 the range of its operand and the expression code. */
2621 extract_range_from_unary_expr (value_range_t *vr, enum tree_code code,
2622 tree type, tree op0)
2626 value_range_t vr0 = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
2628 /* Refuse to operate on certain unary expressions for which we
2629 cannot easily determine a resulting range. */
2630 if (code == FIX_TRUNC_EXPR
2631 || code == FLOAT_EXPR
2632 || code == BIT_NOT_EXPR
2633 || code == CONJ_EXPR)
2635 /* We can still do constant propagation here. */
2636 if ((op0 = op_with_constant_singleton_value_range (op0)) != NULL_TREE)
2638 tree tem = fold_unary (code, type, op0);
2640 && is_gimple_min_invariant (tem)
2641 && !is_overflow_infinity (tem))
2643 set_value_range (vr, VR_RANGE, tem, tem, NULL);
2647 set_value_range_to_varying (vr);
2651 /* Get value ranges for the operand. For constant operands, create
2652 a new value range with the operand to simplify processing. */
2653 if (TREE_CODE (op0) == SSA_NAME)
2654 vr0 = *(get_value_range (op0));
2655 else if (is_gimple_min_invariant (op0))
2656 set_value_range_to_value (&vr0, op0, NULL);
2658 set_value_range_to_varying (&vr0);
2660 /* If VR0 is UNDEFINED, so is the result. */
2661 if (vr0.type == VR_UNDEFINED)
2663 set_value_range_to_undefined (vr);
2667 /* Refuse to operate on symbolic ranges, or if neither operand is
2668 a pointer or integral type. */
2669 if ((!INTEGRAL_TYPE_P (TREE_TYPE (op0))
2670 && !POINTER_TYPE_P (TREE_TYPE (op0)))
2671 || (vr0.type != VR_VARYING
2672 && symbolic_range_p (&vr0)))
2674 set_value_range_to_varying (vr);
2678 /* If the expression involves pointers, we are only interested in
2679 determining if it evaluates to NULL [0, 0] or non-NULL (~[0, 0]). */
2680 if (POINTER_TYPE_P (type) || POINTER_TYPE_P (TREE_TYPE (op0)))
2685 if (range_is_nonnull (&vr0)
2686 || (tree_unary_nonzero_warnv_p (code, type, op0, &sop)
2688 set_value_range_to_nonnull (vr, type);
2689 else if (range_is_null (&vr0))
2690 set_value_range_to_null (vr, type);
2692 set_value_range_to_varying (vr);
2697 /* Handle unary expressions on integer ranges. */
2698 if (CONVERT_EXPR_CODE_P (code)
2699 && INTEGRAL_TYPE_P (type)
2700 && INTEGRAL_TYPE_P (TREE_TYPE (op0)))
2702 tree inner_type = TREE_TYPE (op0);
2703 tree outer_type = type;
2705 /* Always use base-types here. This is important for the
2706 correct signedness. */
2707 if (TREE_TYPE (inner_type))
2708 inner_type = TREE_TYPE (inner_type);
2709 if (TREE_TYPE (outer_type))
2710 outer_type = TREE_TYPE (outer_type);
2712 /* If VR0 is varying and we increase the type precision, assume
2713 a full range for the following transformation. */
2714 if (vr0.type == VR_VARYING
2715 && TYPE_PRECISION (inner_type) < TYPE_PRECISION (outer_type))
2717 vr0.type = VR_RANGE;
2718 vr0.min = TYPE_MIN_VALUE (inner_type);
2719 vr0.max = TYPE_MAX_VALUE (inner_type);
2722 /* If VR0 is a constant range or anti-range and the conversion is
2723 not truncating we can convert the min and max values and
2724 canonicalize the resulting range. Otherwise we can do the
2725 conversion if the size of the range is less than what the
2726 precision of the target type can represent and the range is
2727 not an anti-range. */
2728 if ((vr0.type == VR_RANGE
2729 || vr0.type == VR_ANTI_RANGE)
2730 && TREE_CODE (vr0.min) == INTEGER_CST
2731 && TREE_CODE (vr0.max) == INTEGER_CST
2732 && !is_overflow_infinity (vr0.min)
2733 && !is_overflow_infinity (vr0.max)
2734 && (TYPE_PRECISION (outer_type) >= TYPE_PRECISION (inner_type)
2735 || (vr0.type == VR_RANGE
2736 && integer_zerop (int_const_binop (RSHIFT_EXPR,
2737 int_const_binop (MINUS_EXPR, vr0.max, vr0.min, 0),
2738 size_int (TYPE_PRECISION (outer_type)), 0)))))
2740 tree new_min, new_max;
2741 new_min = force_fit_type_double (outer_type,
2742 TREE_INT_CST_LOW (vr0.min),
2743 TREE_INT_CST_HIGH (vr0.min), 0, 0);
2744 new_max = force_fit_type_double (outer_type,
2745 TREE_INT_CST_LOW (vr0.max),
2746 TREE_INT_CST_HIGH (vr0.max), 0, 0);
2747 set_and_canonicalize_value_range (vr, vr0.type,
2748 new_min, new_max, NULL);
2752 set_value_range_to_varying (vr);
2756 /* Conversion of a VR_VARYING value to a wider type can result
2757 in a usable range. So wait until after we've handled conversions
2758 before dropping the result to VR_VARYING if we had a source
2759 operand that is VR_VARYING. */
2760 if (vr0.type == VR_VARYING)
2762 set_value_range_to_varying (vr);
2766 /* Apply the operation to each end of the range and see what we end
2768 if (code == NEGATE_EXPR
2769 && !TYPE_UNSIGNED (type))
2771 /* NEGATE_EXPR flips the range around. We need to treat
2772 TYPE_MIN_VALUE specially. */
2773 if (is_positive_overflow_infinity (vr0.max))
2774 min = negative_overflow_infinity (type);
2775 else if (is_negative_overflow_infinity (vr0.max))
2776 min = positive_overflow_infinity (type);
2777 else if (!vrp_val_is_min (vr0.max))
2778 min = fold_unary_to_constant (code, type, vr0.max);
2779 else if (needs_overflow_infinity (type))
2781 if (supports_overflow_infinity (type)
2782 && !is_overflow_infinity (vr0.min)
2783 && !vrp_val_is_min (vr0.min))
2784 min = positive_overflow_infinity (type);
2787 set_value_range_to_varying (vr);
2792 min = TYPE_MIN_VALUE (type);
2794 if (is_positive_overflow_infinity (vr0.min))
2795 max = negative_overflow_infinity (type);
2796 else if (is_negative_overflow_infinity (vr0.min))
2797 max = positive_overflow_infinity (type);
2798 else if (!vrp_val_is_min (vr0.min))
2799 max = fold_unary_to_constant (code, type, vr0.min);
2800 else if (needs_overflow_infinity (type))
2802 if (supports_overflow_infinity (type))
2803 max = positive_overflow_infinity (type);
2806 set_value_range_to_varying (vr);
2811 max = TYPE_MIN_VALUE (type);
2813 else if (code == NEGATE_EXPR
2814 && TYPE_UNSIGNED (type))
2816 if (!range_includes_zero_p (&vr0))
2818 max = fold_unary_to_constant (code, type, vr0.min);
2819 min = fold_unary_to_constant (code, type, vr0.max);
2823 if (range_is_null (&vr0))
2824 set_value_range_to_null (vr, type);
2826 set_value_range_to_varying (vr);
2830 else if (code == ABS_EXPR
2831 && !TYPE_UNSIGNED (type))
2833 /* -TYPE_MIN_VALUE = TYPE_MIN_VALUE with flag_wrapv so we can't get a
2835 if (!TYPE_OVERFLOW_UNDEFINED (type)
2836 && ((vr0.type == VR_RANGE
2837 && vrp_val_is_min (vr0.min))
2838 || (vr0.type == VR_ANTI_RANGE
2839 && !vrp_val_is_min (vr0.min)
2840 && !range_includes_zero_p (&vr0))))
2842 set_value_range_to_varying (vr);
2846 /* ABS_EXPR may flip the range around, if the original range
2847 included negative values. */
2848 if (is_overflow_infinity (vr0.min))
2849 min = positive_overflow_infinity (type);
2850 else if (!vrp_val_is_min (vr0.min))
2851 min = fold_unary_to_constant (code, type, vr0.min);
2852 else if (!needs_overflow_infinity (type))
2853 min = TYPE_MAX_VALUE (type);
2854 else if (supports_overflow_infinity (type))
2855 min = positive_overflow_infinity (type);
2858 set_value_range_to_varying (vr);
2862 if (is_overflow_infinity (vr0.max))
2863 max = positive_overflow_infinity (type);
2864 else if (!vrp_val_is_min (vr0.max))
2865 max = fold_unary_to_constant (code, type, vr0.max);
2866 else if (!needs_overflow_infinity (type))
2867 max = TYPE_MAX_VALUE (type);
2868 else if (supports_overflow_infinity (type)
2869 /* We shouldn't generate [+INF, +INF] as set_value_range
2870 doesn't like this and ICEs. */
2871 && !is_positive_overflow_infinity (min))
2872 max = positive_overflow_infinity (type);
2875 set_value_range_to_varying (vr);
2879 cmp = compare_values (min, max);
2881 /* If a VR_ANTI_RANGEs contains zero, then we have
2882 ~[-INF, min(MIN, MAX)]. */
2883 if (vr0.type == VR_ANTI_RANGE)
2885 if (range_includes_zero_p (&vr0))
2887 /* Take the lower of the two values. */
2891 /* Create ~[-INF, min (abs(MIN), abs(MAX))]
2892 or ~[-INF + 1, min (abs(MIN), abs(MAX))] when
2893 flag_wrapv is set and the original anti-range doesn't include
2894 TYPE_MIN_VALUE, remember -TYPE_MIN_VALUE = TYPE_MIN_VALUE. */
2895 if (TYPE_OVERFLOW_WRAPS (type))
2897 tree type_min_value = TYPE_MIN_VALUE (type);
2899 min = (vr0.min != type_min_value
2900 ? int_const_binop (PLUS_EXPR, type_min_value,
2901 integer_one_node, 0)
2906 if (overflow_infinity_range_p (&vr0))
2907 min = negative_overflow_infinity (type);
2909 min = TYPE_MIN_VALUE (type);
2914 /* All else has failed, so create the range [0, INF], even for
2915 flag_wrapv since TYPE_MIN_VALUE is in the original
2917 vr0.type = VR_RANGE;
2918 min = build_int_cst (type, 0);
2919 if (needs_overflow_infinity (type))
2921 if (supports_overflow_infinity (type))
2922 max = positive_overflow_infinity (type);
2925 set_value_range_to_varying (vr);
2930 max = TYPE_MAX_VALUE (type);
2934 /* If the range contains zero then we know that the minimum value in the
2935 range will be zero. */
2936 else if (range_includes_zero_p (&vr0))
2940 min = build_int_cst (type, 0);
2944 /* If the range was reversed, swap MIN and MAX. */
2955 /* Otherwise, operate on each end of the range. */
2956 min = fold_unary_to_constant (code, type, vr0.min);
2957 max = fold_unary_to_constant (code, type, vr0.max);
2959 if (needs_overflow_infinity (type))
2961 gcc_assert (code != NEGATE_EXPR && code != ABS_EXPR);
2963 /* If both sides have overflowed, we don't know
2965 if ((is_overflow_infinity (vr0.min)
2966 || TREE_OVERFLOW (min))
2967 && (is_overflow_infinity (vr0.max)
2968 || TREE_OVERFLOW (max)))
2970 set_value_range_to_varying (vr);
2974 if (is_overflow_infinity (vr0.min))
2976 else if (TREE_OVERFLOW (min))
2978 if (supports_overflow_infinity (type))
2979 min = (tree_int_cst_sgn (min) >= 0
2980 ? positive_overflow_infinity (TREE_TYPE (min))
2981 : negative_overflow_infinity (TREE_TYPE (min)));
2984 set_value_range_to_varying (vr);
2989 if (is_overflow_infinity (vr0.max))
2991 else if (TREE_OVERFLOW (max))
2993 if (supports_overflow_infinity (type))
2994 max = (tree_int_cst_sgn (max) >= 0
2995 ? positive_overflow_infinity (TREE_TYPE (max))
2996 : negative_overflow_infinity (TREE_TYPE (max)));
2999 set_value_range_to_varying (vr);
3006 cmp = compare_values (min, max);
3007 if (cmp == -2 || cmp == 1)
3009 /* If the new range has its limits swapped around (MIN > MAX),
3010 then the operation caused one of them to wrap around, mark
3011 the new range VARYING. */
3012 set_value_range_to_varying (vr);
3015 set_value_range (vr, vr0.type, min, max, NULL);
3019 /* Extract range information from a conditional expression EXPR based on
3020 the ranges of each of its operands and the expression code. */
3023 extract_range_from_cond_expr (value_range_t *vr, tree expr)
3026 value_range_t vr0 = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
3027 value_range_t vr1 = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
3029 /* Get value ranges for each operand. For constant operands, create
3030 a new value range with the operand to simplify processing. */
3031 op0 = COND_EXPR_THEN (expr);
3032 if (TREE_CODE (op0) == SSA_NAME)
3033 vr0 = *(get_value_range (op0));
3034 else if (is_gimple_min_invariant (op0))
3035 set_value_range_to_value (&vr0, op0, NULL);
3037 set_value_range_to_varying (&vr0);
3039 op1 = COND_EXPR_ELSE (expr);
3040 if (TREE_CODE (op1) == SSA_NAME)
3041 vr1 = *(get_value_range (op1));
3042 else if (is_gimple_min_invariant (op1))
3043 set_value_range_to_value (&vr1, op1, NULL);
3045 set_value_range_to_varying (&vr1);
3047 /* The resulting value range is the union of the operand ranges */
3048 vrp_meet (&vr0, &vr1);
3049 copy_value_range (vr, &vr0);
3053 /* Extract range information from a comparison expression EXPR based
3054 on the range of its operand and the expression code. */
3057 extract_range_from_comparison (value_range_t *vr, enum tree_code code,
3058 tree type, tree op0, tree op1)
3063 val = vrp_evaluate_conditional_warnv_with_ops (code, op0, op1, false, &sop,
3066 /* A disadvantage of using a special infinity as an overflow
3067 representation is that we lose the ability to record overflow
3068 when we don't have an infinity. So we have to ignore a result
3069 which relies on overflow. */
3071 if (val && !is_overflow_infinity (val) && !sop)
3073 /* Since this expression was found on the RHS of an assignment,
3074 its type may be different from _Bool. Convert VAL to EXPR's
3076 val = fold_convert (type, val);
3077 if (is_gimple_min_invariant (val))
3078 set_value_range_to_value (vr, val, vr->equiv);
3080 set_value_range (vr, VR_RANGE, val, val, vr->equiv);
3083 /* The result of a comparison is always true or false. */
3084 set_value_range_to_truthvalue (vr, type);
3087 /* Try to derive a nonnegative or nonzero range out of STMT relying
3088 primarily on generic routines in fold in conjunction with range data.
3089 Store the result in *VR */
3092 extract_range_basic (value_range_t *vr, gimple stmt)
3095 tree type = gimple_expr_type (stmt);
3097 if (INTEGRAL_TYPE_P (type)
3098 && gimple_stmt_nonnegative_warnv_p (stmt, &sop))
3099 set_value_range_to_nonnegative (vr, type,
3100 sop || stmt_overflow_infinity (stmt));
3101 else if (vrp_stmt_computes_nonzero (stmt, &sop)
3103 set_value_range_to_nonnull (vr, type);
3105 set_value_range_to_varying (vr);
3109 /* Try to compute a useful range out of assignment STMT and store it
3113 extract_range_from_assignment (value_range_t *vr, gimple stmt)
3115 enum tree_code code = gimple_assign_rhs_code (stmt);
3117 if (code == ASSERT_EXPR)
3118 extract_range_from_assert (vr, gimple_assign_rhs1 (stmt));
3119 else if (code == SSA_NAME)
3120 extract_range_from_ssa_name (vr, gimple_assign_rhs1 (stmt));
3121 else if (TREE_CODE_CLASS (code) == tcc_binary
3122 || code == TRUTH_AND_EXPR
3123 || code == TRUTH_OR_EXPR
3124 || code == TRUTH_XOR_EXPR)
3125 extract_range_from_binary_expr (vr, gimple_assign_rhs_code (stmt),
3126 gimple_expr_type (stmt),
3127 gimple_assign_rhs1 (stmt),
3128 gimple_assign_rhs2 (stmt));
3129 else if (TREE_CODE_CLASS (code) == tcc_unary)
3130 extract_range_from_unary_expr (vr, gimple_assign_rhs_code (stmt),
3131 gimple_expr_type (stmt),
3132 gimple_assign_rhs1 (stmt));
3133 else if (code == COND_EXPR)
3134 extract_range_from_cond_expr (vr, gimple_assign_rhs1 (stmt));
3135 else if (TREE_CODE_CLASS (code) == tcc_comparison)
3136 extract_range_from_comparison (vr, gimple_assign_rhs_code (stmt),
3137 gimple_expr_type (stmt),
3138 gimple_assign_rhs1 (stmt),
3139 gimple_assign_rhs2 (stmt));
3140 else if (get_gimple_rhs_class (code) == GIMPLE_SINGLE_RHS
3141 && is_gimple_min_invariant (gimple_assign_rhs1 (stmt)))
3142 set_value_range_to_value (vr, gimple_assign_rhs1 (stmt), NULL);
3144 set_value_range_to_varying (vr);
3146 if (vr->type == VR_VARYING)
3147 extract_range_basic (vr, stmt);
3150 /* Given a range VR, a LOOP and a variable VAR, determine whether it
3151 would be profitable to adjust VR using scalar evolution information
3152 for VAR. If so, update VR with the new limits. */
3155 adjust_range_with_scev (value_range_t *vr, struct loop *loop,
3156 gimple stmt, tree var)
3158 tree init, step, chrec, tmin, tmax, min, max, type;
3159 enum ev_direction dir;
3161 /* TODO. Don't adjust anti-ranges. An anti-range may provide
3162 better opportunities than a regular range, but I'm not sure. */
3163 if (vr->type == VR_ANTI_RANGE)
3166 chrec = instantiate_parameters (loop, analyze_scalar_evolution (loop, var));
3168 /* Like in PR19590, scev can return a constant function. */
3169 if (is_gimple_min_invariant (chrec))
3171 set_value_range_to_value (vr, chrec, vr->equiv);
3175 if (TREE_CODE (chrec) != POLYNOMIAL_CHREC)
3178 init = initial_condition_in_loop_num (chrec, loop->num);
3179 step = evolution_part_in_loop_num (chrec, loop->num);
3181 /* If STEP is symbolic, we can't know whether INIT will be the
3182 minimum or maximum value in the range. Also, unless INIT is
3183 a simple expression, compare_values and possibly other functions
3184 in tree-vrp won't be able to handle it. */
3185 if (step == NULL_TREE
3186 || !is_gimple_min_invariant (step)
3187 || !valid_value_p (init))
3190 dir = scev_direction (chrec);
3191 if (/* Do not adjust ranges if we do not know whether the iv increases
3192 or decreases, ... */
3193 dir == EV_DIR_UNKNOWN
3194 /* ... or if it may wrap. */
3195 || scev_probably_wraps_p (init, step, stmt, get_chrec_loop (chrec),
3199 /* We use TYPE_MIN_VALUE and TYPE_MAX_VALUE here instead of
3200 negative_overflow_infinity and positive_overflow_infinity,
3201 because we have concluded that the loop probably does not
3204 type = TREE_TYPE (var);
3205 if (POINTER_TYPE_P (type) || !TYPE_MIN_VALUE (type))
3206 tmin = lower_bound_in_type (type, type);
3208 tmin = TYPE_MIN_VALUE (type);
3209 if (POINTER_TYPE_P (type) || !TYPE_MAX_VALUE (type))
3210 tmax = upper_bound_in_type (type, type);
3212 tmax = TYPE_MAX_VALUE (type);
3214 if (vr->type == VR_VARYING || vr->type == VR_UNDEFINED)
3219 /* For VARYING or UNDEFINED ranges, just about anything we get
3220 from scalar evolutions should be better. */
3222 if (dir == EV_DIR_DECREASES)
3227 /* If we would create an invalid range, then just assume we
3228 know absolutely nothing. This may be over-conservative,
3229 but it's clearly safe, and should happen only in unreachable
3230 parts of code, or for invalid programs. */
3231 if (compare_values (min, max) == 1)
3234 set_value_range (vr, VR_RANGE, min, max, vr->equiv);
3236 else if (vr->type == VR_RANGE)
3241 if (dir == EV_DIR_DECREASES)
3243 /* INIT is the maximum value. If INIT is lower than VR->MAX
3244 but no smaller than VR->MIN, set VR->MAX to INIT. */
3245 if (compare_values (init, max) == -1)
3249 /* If we just created an invalid range with the minimum
3250 greater than the maximum, we fail conservatively.
3251 This should happen only in unreachable
3252 parts of code, or for invalid programs. */
3253 if (compare_values (min, max) == 1)
3257 /* According to the loop information, the variable does not
3258 overflow. If we think it does, probably because of an
3259 overflow due to arithmetic on a different INF value,
3261 if (is_negative_overflow_infinity (min))
3266 /* If INIT is bigger than VR->MIN, set VR->MIN to INIT. */
3267 if (compare_values (init, min) == 1)
3271 /* Again, avoid creating invalid range by failing. */
3272 if (compare_values (min, max) == 1)
3276 if (is_positive_overflow_infinity (max))
3280 set_value_range (vr, VR_RANGE, min, max, vr->equiv);
3284 /* Return true if VAR may overflow at STMT. This checks any available
3285 loop information to see if we can determine that VAR does not
3289 vrp_var_may_overflow (tree var, gimple stmt)
3292 tree chrec, init, step;
3294 if (current_loops == NULL)
3297 l = loop_containing_stmt (stmt);
3301 chrec = instantiate_parameters (l, analyze_scalar_evolution (l, var));
3302 if (TREE_CODE (chrec) != POLYNOMIAL_CHREC)
3305 init = initial_condition_in_loop_num (chrec, l->num);
3306 step = evolution_part_in_loop_num (chrec, l->num);
3308 if (step == NULL_TREE
3309 || !is_gimple_min_invariant (step)
3310 || !valid_value_p (init))
3313 /* If we get here, we know something useful about VAR based on the
3314 loop information. If it wraps, it may overflow. */
3316 if (scev_probably_wraps_p (init, step, stmt, get_chrec_loop (chrec),
3320 if (dump_file && (dump_flags & TDF_DETAILS) != 0)
3322 print_generic_expr (dump_file, var, 0);
3323 fprintf (dump_file, ": loop information indicates does not overflow\n");
3330 /* Given two numeric value ranges VR0, VR1 and a comparison code COMP:
3332 - Return BOOLEAN_TRUE_NODE if VR0 COMP VR1 always returns true for
3333 all the values in the ranges.
3335 - Return BOOLEAN_FALSE_NODE if the comparison always returns false.
3337 - Return NULL_TREE if it is not always possible to determine the
3338 value of the comparison.
3340 Also set *STRICT_OVERFLOW_P to indicate whether a range with an
3341 overflow infinity was used in the test. */
3345 compare_ranges (enum tree_code comp, value_range_t *vr0, value_range_t *vr1,
3346 bool *strict_overflow_p)
3348 /* VARYING or UNDEFINED ranges cannot be compared. */
3349 if (vr0->type == VR_VARYING
3350 || vr0->type == VR_UNDEFINED
3351 || vr1->type == VR_VARYING
3352 || vr1->type == VR_UNDEFINED)
3355 /* Anti-ranges need to be handled separately. */
3356 if (vr0->type == VR_ANTI_RANGE || vr1->type == VR_ANTI_RANGE)
3358 /* If both are anti-ranges, then we cannot compute any
3360 if (vr0->type == VR_ANTI_RANGE && vr1->type == VR_ANTI_RANGE)
3363 /* These comparisons are never statically computable. */
3370 /* Equality can be computed only between a range and an
3371 anti-range. ~[VAL1, VAL2] == [VAL1, VAL2] is always false. */
3372 if (vr0->type == VR_RANGE)
3374 /* To simplify processing, make VR0 the anti-range. */
3375 value_range_t *tmp = vr0;
3380 gcc_assert (comp == NE_EXPR || comp == EQ_EXPR);
3382 if (compare_values_warnv (vr0->min, vr1->min, strict_overflow_p) == 0
3383 && compare_values_warnv (vr0->max, vr1->max, strict_overflow_p) == 0)
3384 return (comp == NE_EXPR) ? boolean_true_node : boolean_false_node;
3389 if (!usable_range_p (vr0, strict_overflow_p)
3390 || !usable_range_p (vr1, strict_overflow_p))
3393 /* Simplify processing. If COMP is GT_EXPR or GE_EXPR, switch the
3394 operands around and change the comparison code. */
3395 if (comp == GT_EXPR || comp == GE_EXPR)
3398 comp = (comp == GT_EXPR) ? LT_EXPR : LE_EXPR;
3404 if (comp == EQ_EXPR)
3406 /* Equality may only be computed if both ranges represent
3407 exactly one value. */
3408 if (compare_values_warnv (vr0->min, vr0->max, strict_overflow_p) == 0
3409 && compare_values_warnv (vr1->min, vr1->max, strict_overflow_p) == 0)
3411 int cmp_min = compare_values_warnv (vr0->min, vr1->min,
3413 int cmp_max = compare_values_warnv (vr0->max, vr1->max,
3415 if (cmp_min == 0 && cmp_max == 0)
3416 return boolean_true_node;
3417 else if (cmp_min != -2 && cmp_max != -2)
3418 return boolean_false_node;
3420 /* If [V0_MIN, V1_MAX] < [V1_MIN, V1_MAX] then V0 != V1. */
3421 else if (compare_values_warnv (vr0->min, vr1->max,
3422 strict_overflow_p) == 1
3423 || compare_values_warnv (vr1->min, vr0->max,
3424 strict_overflow_p) == 1)
3425 return boolean_false_node;
3429 else if (comp == NE_EXPR)
3433 /* If VR0 is completely to the left or completely to the right
3434 of VR1, they are always different. Notice that we need to
3435 make sure that both comparisons yield similar results to
3436 avoid comparing values that cannot be compared at
3438 cmp1 = compare_values_warnv (vr0->max, vr1->min, strict_overflow_p);
3439 cmp2 = compare_values_warnv (vr0->min, vr1->max, strict_overflow_p);
3440 if ((cmp1 == -1 && cmp2 == -1) || (cmp1 == 1 && cmp2 == 1))
3441 return boolean_true_node;
3443 /* If VR0 and VR1 represent a single value and are identical,
3445 else if (compare_values_warnv (vr0->min, vr0->max,
3446 strict_overflow_p) == 0
3447 && compare_values_warnv (vr1->min, vr1->max,
3448 strict_overflow_p) == 0
3449 && compare_values_warnv (vr0->min, vr1->min,
3450 strict_overflow_p) == 0
3451 && compare_values_warnv (vr0->max, vr1->max,
3452 strict_overflow_p) == 0)
3453 return boolean_false_node;
3455 /* Otherwise, they may or may not be different. */
3459 else if (comp == LT_EXPR || comp == LE_EXPR)
3463 /* If VR0 is to the left of VR1, return true. */
3464 tst = compare_values_warnv (vr0->max, vr1->min, strict_overflow_p);
3465 if ((comp == LT_EXPR && tst == -1)
3466 || (comp == LE_EXPR && (tst == -1 || tst == 0)))
3468 if (overflow_infinity_range_p (vr0)
3469 || overflow_infinity_range_p (vr1))
3470 *strict_overflow_p = true;
3471 return boolean_true_node;
3474 /* If VR0 is to the right of VR1, return false. */
3475 tst = compare_values_warnv (vr0->min, vr1->max, strict_overflow_p);
3476 if ((comp == LT_EXPR && (tst == 0 || tst == 1))
3477 || (comp == LE_EXPR && tst == 1))
3479 if (overflow_infinity_range_p (vr0)
3480 || overflow_infinity_range_p (vr1))
3481 *strict_overflow_p = true;
3482 return boolean_false_node;
3485 /* Otherwise, we don't know. */
3493 /* Given a value range VR, a value VAL and a comparison code COMP, return
3494 BOOLEAN_TRUE_NODE if VR COMP VAL always returns true for all the
3495 values in VR. Return BOOLEAN_FALSE_NODE if the comparison
3496 always returns false. Return NULL_TREE if it is not always
3497 possible to determine the value of the comparison. Also set
3498 *STRICT_OVERFLOW_P to indicate whether a range with an overflow
3499 infinity was used in the test. */
3502 compare_range_with_value (enum tree_code comp, value_range_t *vr, tree val,
3503 bool *strict_overflow_p)
3505 if (vr->type == VR_VARYING || vr->type == VR_UNDEFINED)
3508 /* Anti-ranges need to be handled separately. */
3509 if (vr->type == VR_ANTI_RANGE)
3511 /* For anti-ranges, the only predicates that we can compute at
3512 compile time are equality and inequality. */
3519 /* ~[VAL_1, VAL_2] OP VAL is known if VAL_1 <= VAL <= VAL_2. */
3520 if (value_inside_range (val, vr) == 1)
3521 return (comp == NE_EXPR) ? boolean_true_node : boolean_false_node;
3526 if (!usable_range_p (vr, strict_overflow_p))
3529 if (comp == EQ_EXPR)
3531 /* EQ_EXPR may only be computed if VR represents exactly
3533 if (compare_values_warnv (vr->min, vr->max, strict_overflow_p) == 0)
3535 int cmp = compare_values_warnv (vr->min, val, strict_overflow_p);
3537 return boolean_true_node;
3538 else if (cmp == -1 || cmp == 1 || cmp == 2)
3539 return boolean_false_node;
3541 else if (compare_values_warnv (val, vr->min, strict_overflow_p) == -1
3542 || compare_values_warnv (vr->max, val, strict_overflow_p) == -1)
3543 return boolean_false_node;
3547 else if (comp == NE_EXPR)
3549 /* If VAL is not inside VR, then they are always different. */
3550 if (compare_values_warnv (vr->max, val, strict_overflow_p) == -1
3551 || compare_values_warnv (vr->min, val, strict_overflow_p) == 1)
3552 return boolean_true_node;
3554 /* If VR represents exactly one value equal to VAL, then return
3556 if (compare_values_warnv (vr->min, vr->max, strict_overflow_p) == 0
3557 && compare_values_warnv (vr->min, val, strict_overflow_p) == 0)
3558 return boolean_false_node;
3560 /* Otherwise, they may or may not be different. */
3563 else if (comp == LT_EXPR || comp == LE_EXPR)
3567 /* If VR is to the left of VAL, return true. */
3568 tst = compare_values_warnv (vr->max, val, strict_overflow_p);
3569 if ((comp == LT_EXPR && tst == -1)
3570 || (comp == LE_EXPR && (tst == -1 || tst == 0)))
3572 if (overflow_infinity_range_p (vr))
3573 *strict_overflow_p = true;
3574 return boolean_true_node;
3577 /* If VR is to the right of VAL, return false. */
3578 tst = compare_values_warnv (vr->min, val, strict_overflow_p);
3579 if ((comp == LT_EXPR && (tst == 0 || tst == 1))
3580 || (comp == LE_EXPR && tst == 1))
3582 if (overflow_infinity_range_p (vr))
3583 *strict_overflow_p = true;
3584 return boolean_false_node;
3587 /* Otherwise, we don't know. */
3590 else if (comp == GT_EXPR || comp == GE_EXPR)
3594 /* If VR is to the right of VAL, return true. */
3595 tst = compare_values_warnv (vr->min, val, strict_overflow_p);
3596 if ((comp == GT_EXPR && tst == 1)
3597 || (comp == GE_EXPR && (tst == 0 || tst == 1)))
3599 if (overflow_infinity_range_p (vr))
3600 *strict_overflow_p = true;
3601 return boolean_true_node;
3604 /* If VR is to the left of VAL, return false. */
3605 tst = compare_values_warnv (vr->max, val, strict_overflow_p);
3606 if ((comp == GT_EXPR && (tst == -1 || tst == 0))
3607 || (comp == GE_EXPR && tst == -1))
3609 if (overflow_infinity_range_p (vr))
3610 *strict_overflow_p = true;
3611 return boolean_false_node;
3614 /* Otherwise, we don't know. */
3622 /* Debugging dumps. */
3624 void dump_value_range (FILE *, value_range_t *);
3625 void debug_value_range (value_range_t *);
3626 void dump_all_value_ranges (FILE *);
3627 void debug_all_value_ranges (void);
3628 void dump_vr_equiv (FILE *, bitmap);
3629 void debug_vr_equiv (bitmap);
3632 /* Dump value range VR to FILE. */
3635 dump_value_range (FILE *file, value_range_t *vr)
3638 fprintf (file, "[]");
3639 else if (vr->type == VR_UNDEFINED)
3640 fprintf (file, "UNDEFINED");
3641 else if (vr->type == VR_RANGE || vr->type == VR_ANTI_RANGE)
3643 tree type = TREE_TYPE (vr->min);
3645 fprintf (file, "%s[", (vr->type == VR_ANTI_RANGE) ? "~" : "");
3647 if (is_negative_overflow_infinity (vr->min))
3648 fprintf (file, "-INF(OVF)");
3649 else if (INTEGRAL_TYPE_P (type)
3650 && !TYPE_UNSIGNED (type)
3651 && vrp_val_is_min (vr->min))
3652 fprintf (file, "-INF");
3654 print_generic_expr (file, vr->min, 0);
3656 fprintf (file, ", ");
3658 if (is_positive_overflow_infinity (vr->max))
3659 fprintf (file, "+INF(OVF)");
3660 else if (INTEGRAL_TYPE_P (type)
3661 && vrp_val_is_max (vr->max))
3662 fprintf (file, "+INF");
3664 print_generic_expr (file, vr->max, 0);
3666 fprintf (file, "]");
3673 fprintf (file, " EQUIVALENCES: { ");
3675 EXECUTE_IF_SET_IN_BITMAP (vr->equiv, 0, i, bi)
3677 print_generic_expr (file, ssa_name (i), 0);
3678 fprintf (file, " ");
3682 fprintf (file, "} (%u elements)", c);
3685 else if (vr->type == VR_VARYING)
3686 fprintf (file, "VARYING");
3688 fprintf (file, "INVALID RANGE");
3692 /* Dump value range VR to stderr. */
3695 debug_value_range (value_range_t *vr)
3697 dump_value_range (stderr, vr);
3698 fprintf (stderr, "\n");
3702 /* Dump value ranges of all SSA_NAMEs to FILE. */
3705 dump_all_value_ranges (FILE *file)
3709 for (i = 0; i < num_ssa_names; i++)
3713 print_generic_expr (file, ssa_name (i), 0);
3714 fprintf (file, ": ");
3715 dump_value_range (file, vr_value[i]);
3716 fprintf (file, "\n");
3720 fprintf (file, "\n");
3724 /* Dump all value ranges to stderr. */
3727 debug_all_value_ranges (void)
3729 dump_all_value_ranges (stderr);
3733 /* Given a COND_EXPR COND of the form 'V OP W', and an SSA name V,
3734 create a new SSA name N and return the assertion assignment
3735 'V = ASSERT_EXPR <V, V OP W>'. */
3738 build_assert_expr_for (tree cond, tree v)
3743 gcc_assert (TREE_CODE (v) == SSA_NAME);
3744 n = duplicate_ssa_name (v, NULL);
3746 if (COMPARISON_CLASS_P (cond))
3748 tree a = build2 (ASSERT_EXPR, TREE_TYPE (v), v, cond);
3749 assertion = gimple_build_assign (n, a);
3751 else if (TREE_CODE (cond) == TRUTH_NOT_EXPR)
3753 /* Given !V, build the assignment N = false. */
3754 tree op0 = TREE_OPERAND (cond, 0);
3755 gcc_assert (op0 == v);
3756 assertion = gimple_build_assign (n, boolean_false_node);
3758 else if (TREE_CODE (cond) == SSA_NAME)
3760 /* Given V, build the assignment N = true. */
3761 gcc_assert (v == cond);
3762 assertion = gimple_build_assign (n, boolean_true_node);
3767 SSA_NAME_DEF_STMT (n) = assertion;
3769 /* The new ASSERT_EXPR, creates a new SSA name that replaces the
3770 operand of the ASSERT_EXPR. Register the new name and the old one
3771 in the replacement table so that we can fix the SSA web after
3772 adding all the ASSERT_EXPRs. */
3773 register_new_name_mapping (n, v);
3779 /* Return false if EXPR is a predicate expression involving floating
3783 fp_predicate (gimple stmt)
3785 GIMPLE_CHECK (stmt, GIMPLE_COND);
3787 return FLOAT_TYPE_P (TREE_TYPE (gimple_cond_lhs (stmt)));
3791 /* If the range of values taken by OP can be inferred after STMT executes,
3792 return the comparison code (COMP_CODE_P) and value (VAL_P) that
3793 describes the inferred range. Return true if a range could be
3797 infer_value_range (gimple stmt, tree op, enum tree_code *comp_code_p, tree *val_p)
3800 *comp_code_p = ERROR_MARK;
3802 /* Do not attempt to infer anything in names that flow through
3804 if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (op))
3807 /* Similarly, don't infer anything from statements that may throw
3809 if (stmt_could_throw_p (stmt))
3812 /* If STMT is the last statement of a basic block with no
3813 successors, there is no point inferring anything about any of its
3814 operands. We would not be able to find a proper insertion point
3815 for the assertion, anyway. */
3816 if (stmt_ends_bb_p (stmt) && EDGE_COUNT (gimple_bb (stmt)->succs) == 0)
3819 /* We can only assume that a pointer dereference will yield
3820 non-NULL if -fdelete-null-pointer-checks is enabled. */
3821 if (flag_delete_null_pointer_checks
3822 && POINTER_TYPE_P (TREE_TYPE (op))
3823 && gimple_code (stmt) != GIMPLE_ASM)
3825 unsigned num_uses, num_loads, num_stores;
3827 count_uses_and_derefs (op, stmt, &num_uses, &num_loads, &num_stores);
3828 if (num_loads + num_stores > 0)
3830 *val_p = build_int_cst (TREE_TYPE (op), 0);
3831 *comp_code_p = NE_EXPR;
3840 void dump_asserts_for (FILE *, tree);
3841 void debug_asserts_for (tree);
3842 void dump_all_asserts (FILE *);
3843 void debug_all_asserts (void);
3845 /* Dump all the registered assertions for NAME to FILE. */
3848 dump_asserts_for (FILE *file, tree name)
3852 fprintf (file, "Assertions to be inserted for ");
3853 print_generic_expr (file, name, 0);
3854 fprintf (file, "\n");
3856 loc = asserts_for[SSA_NAME_VERSION (name)];
3859 fprintf (file, "\t");
3860 print_gimple_stmt (file, gsi_stmt (loc->si), 0, 0);
3861 fprintf (file, "\n\tBB #%d", loc->bb->index);
3864 fprintf (file, "\n\tEDGE %d->%d", loc->e->src->index,
3865 loc->e->dest->index);
3866 dump_edge_info (file, loc->e, 0);
3868 fprintf (file, "\n\tPREDICATE: ");
3869 print_generic_expr (file, name, 0);
3870 fprintf (file, " %s ", tree_code_name[(int)loc->comp_code]);
3871 print_generic_expr (file, loc->val, 0);
3872 fprintf (file, "\n\n");
3876 fprintf (file, "\n");
3880 /* Dump all the registered assertions for NAME to stderr. */
3883 debug_asserts_for (tree name)
3885 dump_asserts_for (stderr, name);
3889 /* Dump all the registered assertions for all the names to FILE. */
3892 dump_all_asserts (FILE *file)
3897 fprintf (file, "\nASSERT_EXPRs to be inserted\n\n");
3898 EXECUTE_IF_SET_IN_BITMAP (need_assert_for, 0, i, bi)
3899 dump_asserts_for (file, ssa_name (i));
3900 fprintf (file, "\n");
3904 /* Dump all the registered assertions for all the names to stderr. */
3907 debug_all_asserts (void)
3909 dump_all_asserts (stderr);
3913 /* If NAME doesn't have an ASSERT_EXPR registered for asserting
3914 'EXPR COMP_CODE VAL' at a location that dominates block BB or
3915 E->DEST, then register this location as a possible insertion point
3916 for ASSERT_EXPR <NAME, EXPR COMP_CODE VAL>.
3918 BB, E and SI provide the exact insertion point for the new
3919 ASSERT_EXPR. If BB is NULL, then the ASSERT_EXPR is to be inserted
3920 on edge E. Otherwise, if E is NULL, the ASSERT_EXPR is inserted on
3921 BB. If SI points to a COND_EXPR or a SWITCH_EXPR statement, then E
3922 must not be NULL. */
3925 register_new_assert_for (tree name, tree expr,
3926 enum tree_code comp_code,
3930 gimple_stmt_iterator si)
3932 assert_locus_t n, loc, last_loc;
3934 basic_block dest_bb;
3936 #if defined ENABLE_CHECKING
3937 gcc_assert (bb == NULL || e == NULL);
3940 gcc_assert (gimple_code (gsi_stmt (si)) != GIMPLE_COND
3941 && gimple_code (gsi_stmt (si)) != GIMPLE_SWITCH);
3944 /* Never build an assert comparing against an integer constant with
3945 TREE_OVERFLOW set. This confuses our undefined overflow warning
3947 if (TREE_CODE (val) == INTEGER_CST
3948 && TREE_OVERFLOW (val))
3949 val = build_int_cst_wide (TREE_TYPE (val),
3950 TREE_INT_CST_LOW (val), TREE_INT_CST_HIGH (val));
3952 /* The new assertion A will be inserted at BB or E. We need to
3953 determine if the new location is dominated by a previously
3954 registered location for A. If we are doing an edge insertion,
3955 assume that A will be inserted at E->DEST. Note that this is not
3958 If E is a critical edge, it will be split. But even if E is
3959 split, the new block will dominate the same set of blocks that
3962 The reverse, however, is not true, blocks dominated by E->DEST
3963 will not be dominated by the new block created to split E. So,
3964 if the insertion location is on a critical edge, we will not use
3965 the new location to move another assertion previously registered
3966 at a block dominated by E->DEST. */
3967 dest_bb = (bb) ? bb : e->dest;
3969 /* If NAME already has an ASSERT_EXPR registered for COMP_CODE and
3970 VAL at a block dominating DEST_BB, then we don't need to insert a new
3971 one. Similarly, if the same assertion already exists at a block
3972 dominated by DEST_BB and the new location is not on a critical
3973 edge, then update the existing location for the assertion (i.e.,
3974 move the assertion up in the dominance tree).
3976 Note, this is implemented as a simple linked list because there
3977 should not be more than a handful of assertions registered per
3978 name. If this becomes a performance problem, a table hashed by
3979 COMP_CODE and VAL could be implemented. */
3980 loc = asserts_for[SSA_NAME_VERSION (name)];
3985 if (loc->comp_code == comp_code
3987 || operand_equal_p (loc->val, val, 0))
3988 && (loc->expr == expr
3989 || operand_equal_p (loc->expr, expr, 0)))
3991 /* If the assertion NAME COMP_CODE VAL has already been
3992 registered at a basic block that dominates DEST_BB, then
3993 we don't need to insert the same assertion again. Note
3994 that we don't check strict dominance here to avoid
3995 replicating the same assertion inside the same basic
3996 block more than once (e.g., when a pointer is
3997 dereferenced several times inside a block).
3999 An exception to this rule are edge insertions. If the
4000 new assertion is to be inserted on edge E, then it will
4001 dominate all the other insertions that we may want to
4002 insert in DEST_BB. So, if we are doing an edge
4003 insertion, don't do this dominance check. */
4005 && dominated_by_p (CDI_DOMINATORS, dest_bb, loc->bb))
4008 /* Otherwise, if E is not a critical edge and DEST_BB
4009 dominates the existing location for the assertion, move
4010 the assertion up in the dominance tree by updating its
4011 location information. */
4012 if ((e == NULL || !EDGE_CRITICAL_P (e))
4013 && dominated_by_p (CDI_DOMINATORS, loc->bb, dest_bb))
4022 /* Update the last node of the list and move to the next one. */
4027 /* If we didn't find an assertion already registered for
4028 NAME COMP_CODE VAL, add a new one at the end of the list of
4029 assertions associated with NAME. */
4030 n = XNEW (struct assert_locus_d);
4034 n->comp_code = comp_code;
4042 asserts_for[SSA_NAME_VERSION (name)] = n;
4044 bitmap_set_bit (need_assert_for, SSA_NAME_VERSION (name));
4047 /* (COND_OP0 COND_CODE COND_OP1) is a predicate which uses NAME.
4048 Extract a suitable test code and value and store them into *CODE_P and
4049 *VAL_P so the predicate is normalized to NAME *CODE_P *VAL_P.
4051 If no extraction was possible, return FALSE, otherwise return TRUE.
4053 If INVERT is true, then we invert the result stored into *CODE_P. */
4056 extract_code_and_val_from_cond_with_ops (tree name, enum tree_code cond_code,
4057 tree cond_op0, tree cond_op1,
4058 bool invert, enum tree_code *code_p,
4061 enum tree_code comp_code;
4064 /* Otherwise, we have a comparison of the form NAME COMP VAL
4065 or VAL COMP NAME. */
4066 if (name == cond_op1)
4068 /* If the predicate is of the form VAL COMP NAME, flip
4069 COMP around because we need to register NAME as the
4070 first operand in the predicate. */
4071 comp_code = swap_tree_comparison (cond_code);
4076 /* The comparison is of the form NAME COMP VAL, so the
4077 comparison code remains unchanged. */
4078 comp_code = cond_code;
4082 /* Invert the comparison code as necessary. */
4084 comp_code = invert_tree_comparison (comp_code, 0);
4086 /* VRP does not handle float types. */
4087 if (SCALAR_FLOAT_TYPE_P (TREE_TYPE (val)))
4090 /* Do not register always-false predicates.
4091 FIXME: this works around a limitation in fold() when dealing with
4092 enumerations. Given 'enum { N1, N2 } x;', fold will not
4093 fold 'if (x > N2)' to 'if (0)'. */
4094 if ((comp_code == GT_EXPR || comp_code == LT_EXPR)
4095 && INTEGRAL_TYPE_P (TREE_TYPE (val)))
4097 tree min = TYPE_MIN_VALUE (TREE_TYPE (val));
4098 tree max = TYPE_MAX_VALUE (TREE_TYPE (val));
4100 if (comp_code == GT_EXPR
4102 || compare_values (val, max) == 0))
4105 if (comp_code == LT_EXPR
4107 || compare_values (val, min) == 0))
4110 *code_p = comp_code;
4115 /* Try to register an edge assertion for SSA name NAME on edge E for
4116 the condition COND contributing to the conditional jump pointed to by BSI.
4117 Invert the condition COND if INVERT is true.
4118 Return true if an assertion for NAME could be registered. */
4121 register_edge_assert_for_2 (tree name, edge e, gimple_stmt_iterator bsi,
4122 enum tree_code cond_code,
4123 tree cond_op0, tree cond_op1, bool invert)
4126 enum tree_code comp_code;
4127 bool retval = false;
4129 if (!extract_code_and_val_from_cond_with_ops (name, cond_code,
4132 invert, &comp_code, &val))
4135 /* Only register an ASSERT_EXPR if NAME was found in the sub-graph
4136 reachable from E. */
4137 if (live_on_edge (e, name)
4138 && !has_single_use (name))
4140 register_new_assert_for (name, name, comp_code, val, NULL, e, bsi);
4144 /* In the case of NAME <= CST and NAME being defined as
4145 NAME = (unsigned) NAME2 + CST2 we can assert NAME2 >= -CST2
4146 and NAME2 <= CST - CST2. We can do the same for NAME > CST.
4147 This catches range and anti-range tests. */
4148 if ((comp_code == LE_EXPR
4149 || comp_code == GT_EXPR)
4150 && TREE_CODE (val) == INTEGER_CST
4151 && TYPE_UNSIGNED (TREE_TYPE (val)))
4153 gimple def_stmt = SSA_NAME_DEF_STMT (name);
4154 tree cst2 = NULL_TREE, name2 = NULL_TREE, name3 = NULL_TREE;
4156 /* Extract CST2 from the (optional) addition. */
4157 if (is_gimple_assign (def_stmt)
4158 && gimple_assign_rhs_code (def_stmt) == PLUS_EXPR)
4160 name2 = gimple_assign_rhs1 (def_stmt);
4161 cst2 = gimple_assign_rhs2 (def_stmt);
4162 if (TREE_CODE (name2) == SSA_NAME
4163 && TREE_CODE (cst2) == INTEGER_CST)
4164 def_stmt = SSA_NAME_DEF_STMT (name2);
4167 /* Extract NAME2 from the (optional) sign-changing cast. */
4168 if (gimple_assign_cast_p (def_stmt))
4170 if (CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (def_stmt))
4171 && ! TYPE_UNSIGNED (TREE_TYPE (gimple_assign_rhs1 (def_stmt)))
4172 && (TYPE_PRECISION (gimple_expr_type (def_stmt))
4173 == TYPE_PRECISION (TREE_TYPE (gimple_assign_rhs1 (def_stmt)))))
4174 name3 = gimple_assign_rhs1 (def_stmt);
4177 /* If name3 is used later, create an ASSERT_EXPR for it. */
4178 if (name3 != NULL_TREE
4179 && TREE_CODE (name3) == SSA_NAME
4180 && (cst2 == NULL_TREE
4181 || TREE_CODE (cst2) == INTEGER_CST)
4182 && INTEGRAL_TYPE_P (TREE_TYPE (name3))
4183 && live_on_edge (e, name3)
4184 && !has_single_use (name3))
4188 /* Build an expression for the range test. */
4189 tmp = build1 (NOP_EXPR, TREE_TYPE (name), name3);
4190 if (cst2 != NULL_TREE)
4191 tmp = build2 (PLUS_EXPR, TREE_TYPE (name), tmp, cst2);
4195 fprintf (dump_file, "Adding assert for ");
4196 print_generic_expr (dump_file, name3, 0);
4197 fprintf (dump_file, " from ");
4198 print_generic_expr (dump_file, tmp, 0);
4199 fprintf (dump_file, "\n");
4202 register_new_assert_for (name3, tmp, comp_code, val, NULL, e, bsi);
4207 /* If name2 is used later, create an ASSERT_EXPR for it. */
4208 if (name2 != NULL_TREE
4209 && TREE_CODE (name2) == SSA_NAME
4210 && TREE_CODE (cst2) == INTEGER_CST
4211 && INTEGRAL_TYPE_P (TREE_TYPE (name2))
4212 && live_on_edge (e, name2)
4213 && !has_single_use (name2))
4217 /* Build an expression for the range test. */
4219 if (TREE_TYPE (name) != TREE_TYPE (name2))
4220 tmp = build1 (NOP_EXPR, TREE_TYPE (name), tmp);
4221 if (cst2 != NULL_TREE)
4222 tmp = build2 (PLUS_EXPR, TREE_TYPE (name), tmp, cst2);
4226 fprintf (dump_file, "Adding assert for ");
4227 print_generic_expr (dump_file, name2, 0);
4228 fprintf (dump_file, " from ");
4229 print_generic_expr (dump_file, tmp, 0);
4230 fprintf (dump_file, "\n");
4233 register_new_assert_for (name2, tmp, comp_code, val, NULL, e, bsi);
4242 /* OP is an operand of a truth value expression which is known to have
4243 a particular value. Register any asserts for OP and for any
4244 operands in OP's defining statement.
4246 If CODE is EQ_EXPR, then we want to register OP is zero (false),
4247 if CODE is NE_EXPR, then we want to register OP is nonzero (true). */
4250 register_edge_assert_for_1 (tree op, enum tree_code code,
4251 edge e, gimple_stmt_iterator bsi)
4253 bool retval = false;
4256 enum tree_code rhs_code;
4258 /* We only care about SSA_NAMEs. */
4259 if (TREE_CODE (op) != SSA_NAME)
4262 /* We know that OP will have a zero or nonzero value. If OP is used
4263 more than once go ahead and register an assert for OP.
4265 The FOUND_IN_SUBGRAPH support is not helpful in this situation as
4266 it will always be set for OP (because OP is used in a COND_EXPR in
4268 if (!has_single_use (op))
4270 val = build_int_cst (TREE_TYPE (op), 0);
4271 register_new_assert_for (op, op, code, val, NULL, e, bsi);
4275 /* Now look at how OP is set. If it's set from a comparison,
4276 a truth operation or some bit operations, then we may be able
4277 to register information about the operands of that assignment. */
4278 op_def = SSA_NAME_DEF_STMT (op);
4279 if (gimple_code (op_def) != GIMPLE_ASSIGN)
4282 rhs_code = gimple_assign_rhs_code (op_def);
4284 if (TREE_CODE_CLASS (rhs_code) == tcc_comparison)
4286 bool invert = (code == EQ_EXPR ? true : false);
4287 tree op0 = gimple_assign_rhs1 (op_def);
4288 tree op1 = gimple_assign_rhs2 (op_def);
4290 if (TREE_CODE (op0) == SSA_NAME)
4291 retval |= register_edge_assert_for_2 (op0, e, bsi, rhs_code, op0, op1,
4293 if (TREE_CODE (op1) == SSA_NAME)
4294 retval |= register_edge_assert_for_2 (op1, e, bsi, rhs_code, op0, op1,
4297 else if ((code == NE_EXPR
4298 && (gimple_assign_rhs_code (op_def) == TRUTH_AND_EXPR
4299 || gimple_assign_rhs_code (op_def) == BIT_AND_EXPR))
4301 && (gimple_assign_rhs_code (op_def) == TRUTH_OR_EXPR
4302 || gimple_assign_rhs_code (op_def) == BIT_IOR_EXPR)))
4304 /* Recurse on each operand. */
4305 retval |= register_edge_assert_for_1 (gimple_assign_rhs1 (op_def),
4307 retval |= register_edge_assert_for_1 (gimple_assign_rhs2 (op_def),
4310 else if (gimple_assign_rhs_code (op_def) == TRUTH_NOT_EXPR)
4312 /* Recurse, flipping CODE. */
4313 code = invert_tree_comparison (code, false);
4314 retval |= register_edge_assert_for_1 (gimple_assign_rhs1 (op_def),
4317 else if (gimple_assign_rhs_code (op_def) == SSA_NAME)
4319 /* Recurse through the copy. */
4320 retval |= register_edge_assert_for_1 (gimple_assign_rhs1 (op_def),
4323 else if (CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (op_def)))
4325 /* Recurse through the type conversion. */
4326 retval |= register_edge_assert_for_1 (gimple_assign_rhs1 (op_def),
4333 /* Try to register an edge assertion for SSA name NAME on edge E for
4334 the condition COND contributing to the conditional jump pointed to by SI.
4335 Return true if an assertion for NAME could be registered. */
4338 register_edge_assert_for (tree name, edge e, gimple_stmt_iterator si,
4339 enum tree_code cond_code, tree cond_op0,
4343 enum tree_code comp_code;
4344 bool retval = false;
4345 bool is_else_edge = (e->flags & EDGE_FALSE_VALUE) != 0;
4347 /* Do not attempt to infer anything in names that flow through
4349 if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (name))
4352 if (!extract_code_and_val_from_cond_with_ops (name, cond_code,
4358 /* Register ASSERT_EXPRs for name. */
4359 retval |= register_edge_assert_for_2 (name, e, si, cond_code, cond_op0,
4360 cond_op1, is_else_edge);
4363 /* If COND is effectively an equality test of an SSA_NAME against
4364 the value zero or one, then we may be able to assert values
4365 for SSA_NAMEs which flow into COND. */
4367 /* In the case of NAME == 1 or NAME != 0, for TRUTH_AND_EXPR defining
4368 statement of NAME we can assert both operands of the TRUTH_AND_EXPR
4369 have nonzero value. */
4370 if (((comp_code == EQ_EXPR && integer_onep (val))
4371 || (comp_code == NE_EXPR && integer_zerop (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_AND_EXPR
4377 || gimple_assign_rhs_code (def_stmt) == BIT_AND_EXPR))
4379 tree op0 = gimple_assign_rhs1 (def_stmt);
4380 tree op1 = gimple_assign_rhs2 (def_stmt);
4381 retval |= register_edge_assert_for_1 (op0, NE_EXPR, e, si);
4382 retval |= register_edge_assert_for_1 (op1, NE_EXPR, e, si);
4386 /* In the case of NAME == 0 or NAME != 1, for TRUTH_OR_EXPR defining
4387 statement of NAME we can assert both operands of the TRUTH_OR_EXPR
4389 if (((comp_code == EQ_EXPR && integer_zerop (val))
4390 || (comp_code == NE_EXPR && integer_onep (val))))
4392 gimple def_stmt = SSA_NAME_DEF_STMT (name);
4394 if (is_gimple_assign (def_stmt)
4395 && (gimple_assign_rhs_code (def_stmt) == TRUTH_OR_EXPR
4396 /* For BIT_IOR_EXPR only if NAME == 0 both operands have
4397 necessarily zero value. */
4398 || (comp_code == EQ_EXPR
4399 && (gimple_assign_rhs_code (def_stmt) == BIT_IOR_EXPR))))
4401 tree op0 = gimple_assign_rhs1 (def_stmt);
4402 tree op1 = gimple_assign_rhs2 (def_stmt);
4403 retval |= register_edge_assert_for_1 (op0, EQ_EXPR, e, si);
4404 retval |= register_edge_assert_for_1 (op1, EQ_EXPR, e, si);
4412 /* Determine whether the outgoing edges of BB should receive an
4413 ASSERT_EXPR for each of the operands of BB's LAST statement.
4414 The last statement of BB must be a COND_EXPR.
4416 If any of the sub-graphs rooted at BB have an interesting use of
4417 the predicate operands, an assert location node is added to the
4418 list of assertions for the corresponding operands. */
4421 find_conditional_asserts (basic_block bb, gimple last)
4424 gimple_stmt_iterator bsi;
4430 need_assert = false;
4431 bsi = gsi_for_stmt (last);
4433 /* Look for uses of the operands in each of the sub-graphs
4434 rooted at BB. We need to check each of the outgoing edges
4435 separately, so that we know what kind of ASSERT_EXPR to
4437 FOR_EACH_EDGE (e, ei, bb->succs)
4442 /* Register the necessary assertions for each operand in the
4443 conditional predicate. */
4444 FOR_EACH_SSA_TREE_OPERAND (op, last, iter, SSA_OP_USE)
4446 need_assert |= register_edge_assert_for (op, e, bsi,
4447 gimple_cond_code (last),
4448 gimple_cond_lhs (last),
4449 gimple_cond_rhs (last));
4456 /* Compare two case labels sorting first by the destination label uid
4457 and then by the case value. */
4460 compare_case_labels (const void *p1, const void *p2)
4462 const_tree const case1 = *(const_tree const*)p1;
4463 const_tree const case2 = *(const_tree const*)p2;
4464 unsigned int uid1 = DECL_UID (CASE_LABEL (case1));
4465 unsigned int uid2 = DECL_UID (CASE_LABEL (case2));
4469 else if (uid1 == uid2)
4471 /* Make sure the default label is first in a group. */
4472 if (!CASE_LOW (case1))
4474 else if (!CASE_LOW (case2))
4477 return tree_int_cst_compare (CASE_LOW (case1), CASE_LOW (case2));
4483 /* Determine whether the outgoing edges of BB should receive an
4484 ASSERT_EXPR for each of the operands of BB's LAST statement.
4485 The last statement of BB must be a SWITCH_EXPR.
4487 If any of the sub-graphs rooted at BB have an interesting use of
4488 the predicate operands, an assert location node is added to the
4489 list of assertions for the corresponding operands. */
4492 find_switch_asserts (basic_block bb, gimple last)
4495 gimple_stmt_iterator bsi;
4499 size_t n = gimple_switch_num_labels(last);
4500 #if GCC_VERSION >= 4000
4503 /* Work around GCC 3.4 bug (PR 37086). */
4504 volatile unsigned int idx;
4507 need_assert = false;
4508 bsi = gsi_for_stmt (last);
4509 op = gimple_switch_index (last);
4510 if (TREE_CODE (op) != SSA_NAME)
4513 /* Build a vector of case labels sorted by destination label. */
4514 vec2 = make_tree_vec (n);
4515 for (idx = 0; idx < n; ++idx)
4516 TREE_VEC_ELT (vec2, idx) = gimple_switch_label (last, idx);
4517 qsort (&TREE_VEC_ELT (vec2, 0), n, sizeof (tree), compare_case_labels);
4519 for (idx = 0; idx < n; ++idx)
4522 tree cl = TREE_VEC_ELT (vec2, idx);
4524 min = CASE_LOW (cl);
4525 max = CASE_HIGH (cl);
4527 /* If there are multiple case labels with the same destination
4528 we need to combine them to a single value range for the edge. */
4530 && CASE_LABEL (cl) == CASE_LABEL (TREE_VEC_ELT (vec2, idx + 1)))
4532 /* Skip labels until the last of the group. */
4536 && CASE_LABEL (cl) == CASE_LABEL (TREE_VEC_ELT (vec2, idx)));
4539 /* Pick up the maximum of the case label range. */
4540 if (CASE_HIGH (TREE_VEC_ELT (vec2, idx)))
4541 max = CASE_HIGH (TREE_VEC_ELT (vec2, idx));
4543 max = CASE_LOW (TREE_VEC_ELT (vec2, idx));
4546 /* Nothing to do if the range includes the default label until we
4547 can register anti-ranges. */
4548 if (min == NULL_TREE)
4551 /* Find the edge to register the assert expr on. */
4552 e = find_edge (bb, label_to_block (CASE_LABEL (cl)));
4554 /* Register the necessary assertions for the operand in the
4556 need_assert |= register_edge_assert_for (op, e, bsi,
4557 max ? GE_EXPR : EQ_EXPR,
4559 fold_convert (TREE_TYPE (op),
4563 need_assert |= register_edge_assert_for (op, e, bsi, LE_EXPR,
4565 fold_convert (TREE_TYPE (op),
4574 /* Traverse all the statements in block BB looking for statements that
4575 may generate useful assertions for the SSA names in their operand.
4576 If a statement produces a useful assertion A for name N_i, then the
4577 list of assertions already generated for N_i is scanned to
4578 determine if A is actually needed.
4580 If N_i already had the assertion A at a location dominating the
4581 current location, then nothing needs to be done. Otherwise, the
4582 new location for A is recorded instead.
4584 1- For every statement S in BB, all the variables used by S are
4585 added to bitmap FOUND_IN_SUBGRAPH.
4587 2- If statement S uses an operand N in a way that exposes a known
4588 value range for N, then if N was not already generated by an
4589 ASSERT_EXPR, create a new assert location for N. For instance,
4590 if N is a pointer and the statement dereferences it, we can
4591 assume that N is not NULL.
4593 3- COND_EXPRs are a special case of #2. We can derive range
4594 information from the predicate but need to insert different
4595 ASSERT_EXPRs for each of the sub-graphs rooted at the
4596 conditional block. If the last statement of BB is a conditional
4597 expression of the form 'X op Y', then
4599 a) Remove X and Y from the set FOUND_IN_SUBGRAPH.
4601 b) If the conditional is the only entry point to the sub-graph
4602 corresponding to the THEN_CLAUSE, recurse into it. On
4603 return, if X and/or Y are marked in FOUND_IN_SUBGRAPH, then
4604 an ASSERT_EXPR is added for the corresponding variable.
4606 c) Repeat step (b) on the ELSE_CLAUSE.
4608 d) Mark X and Y in FOUND_IN_SUBGRAPH.
4617 In this case, an assertion on the THEN clause is useful to
4618 determine that 'a' is always 9 on that edge. However, an assertion
4619 on the ELSE clause would be unnecessary.
4621 4- If BB does not end in a conditional expression, then we recurse
4622 into BB's dominator children.
4624 At the end of the recursive traversal, every SSA name will have a
4625 list of locations where ASSERT_EXPRs should be added. When a new
4626 location for name N is found, it is registered by calling
4627 register_new_assert_for. That function keeps track of all the
4628 registered assertions to prevent adding unnecessary assertions.
4629 For instance, if a pointer P_4 is dereferenced more than once in a
4630 dominator tree, only the location dominating all the dereference of
4631 P_4 will receive an ASSERT_EXPR.
4633 If this function returns true, then it means that there are names
4634 for which we need to generate ASSERT_EXPRs. Those assertions are
4635 inserted by process_assert_insertions. */
4638 find_assert_locations_1 (basic_block bb, sbitmap live)
4640 gimple_stmt_iterator si;
4645 need_assert = false;
4646 last = last_stmt (bb);
4648 /* If BB's last statement is a conditional statement involving integer
4649 operands, determine if we need to add ASSERT_EXPRs. */
4651 && gimple_code (last) == GIMPLE_COND
4652 && !fp_predicate (last)
4653 && !ZERO_SSA_OPERANDS (last, SSA_OP_USE))
4654 need_assert |= find_conditional_asserts (bb, last);
4656 /* If BB's last statement is a switch statement involving integer
4657 operands, determine if we need to add ASSERT_EXPRs. */
4659 && gimple_code (last) == GIMPLE_SWITCH
4660 && !ZERO_SSA_OPERANDS (last, SSA_OP_USE))
4661 need_assert |= find_switch_asserts (bb, last);
4663 /* Traverse all the statements in BB marking used names and looking
4664 for statements that may infer assertions for their used operands. */
4665 for (si = gsi_start_bb (bb); !gsi_end_p (si); gsi_next (&si))
4671 stmt = gsi_stmt (si);
4673 /* See if we can derive an assertion for any of STMT's operands. */
4674 FOR_EACH_SSA_TREE_OPERAND (op, stmt, i, SSA_OP_USE)
4677 enum tree_code comp_code;
4679 /* Mark OP in our live bitmap. */
4680 SET_BIT (live, SSA_NAME_VERSION (op));
4682 /* If OP is used in such a way that we can infer a value
4683 range for it, and we don't find a previous assertion for
4684 it, create a new assertion location node for OP. */
4685 if (infer_value_range (stmt, op, &comp_code, &value))
4687 /* If we are able to infer a nonzero value range for OP,
4688 then walk backwards through the use-def chain to see if OP
4689 was set via a typecast.
4691 If so, then we can also infer a nonzero value range
4692 for the operand of the NOP_EXPR. */
4693 if (comp_code == NE_EXPR && integer_zerop (value))
4696 gimple def_stmt = SSA_NAME_DEF_STMT (t);
4698 while (is_gimple_assign (def_stmt)
4699 && gimple_assign_rhs_code (def_stmt) == NOP_EXPR
4701 (gimple_assign_rhs1 (def_stmt)) == SSA_NAME
4703 (TREE_TYPE (gimple_assign_rhs1 (def_stmt))))
4705 t = gimple_assign_rhs1 (def_stmt);
4706 def_stmt = SSA_NAME_DEF_STMT (t);
4708 /* Note we want to register the assert for the
4709 operand of the NOP_EXPR after SI, not after the
4711 if (! has_single_use (t))
4713 register_new_assert_for (t, t, comp_code, value,
4720 /* If OP is used only once, namely in this STMT, don't
4721 bother creating an ASSERT_EXPR for it. Such an
4722 ASSERT_EXPR would do nothing but increase compile time. */
4723 if (!has_single_use (op))
4725 register_new_assert_for (op, op, comp_code, value,
4733 /* Traverse all PHI nodes in BB marking used operands. */
4734 for (si = gsi_start_phis (bb); !gsi_end_p(si); gsi_next (&si))
4736 use_operand_p arg_p;
4738 phi = gsi_stmt (si);
4740 FOR_EACH_PHI_ARG (arg_p, phi, i, SSA_OP_USE)
4742 tree arg = USE_FROM_PTR (arg_p);
4743 if (TREE_CODE (arg) == SSA_NAME)
4744 SET_BIT (live, SSA_NAME_VERSION (arg));
4751 /* Do an RPO walk over the function computing SSA name liveness
4752 on-the-fly and deciding on assert expressions to insert.
4753 Returns true if there are assert expressions to be inserted. */
4756 find_assert_locations (void)
4758 int *rpo = XCNEWVEC (int, last_basic_block + NUM_FIXED_BLOCKS);
4759 int *bb_rpo = XCNEWVEC (int, last_basic_block + NUM_FIXED_BLOCKS);
4760 int *last_rpo = XCNEWVEC (int, last_basic_block + NUM_FIXED_BLOCKS);
4764 live = XCNEWVEC (sbitmap, last_basic_block + NUM_FIXED_BLOCKS);
4765 rpo_cnt = pre_and_rev_post_order_compute (NULL, rpo, false);
4766 for (i = 0; i < rpo_cnt; ++i)
4769 need_asserts = false;
4770 for (i = rpo_cnt-1; i >= 0; --i)
4772 basic_block bb = BASIC_BLOCK (rpo[i]);
4778 live[rpo[i]] = sbitmap_alloc (num_ssa_names);
4779 sbitmap_zero (live[rpo[i]]);
4782 /* Process BB and update the live information with uses in
4784 need_asserts |= find_assert_locations_1 (bb, live[rpo[i]]);
4786 /* Merge liveness into the predecessor blocks and free it. */
4787 if (!sbitmap_empty_p (live[rpo[i]]))
4790 FOR_EACH_EDGE (e, ei, bb->preds)
4792 int pred = e->src->index;
4793 if (e->flags & EDGE_DFS_BACK)
4798 live[pred] = sbitmap_alloc (num_ssa_names);
4799 sbitmap_zero (live[pred]);
4801 sbitmap_a_or_b (live[pred], live[pred], live[rpo[i]]);
4803 if (bb_rpo[pred] < pred_rpo)
4804 pred_rpo = bb_rpo[pred];
4807 /* Record the RPO number of the last visited block that needs
4808 live information from this block. */
4809 last_rpo[rpo[i]] = pred_rpo;
4813 sbitmap_free (live[rpo[i]]);
4814 live[rpo[i]] = NULL;
4817 /* We can free all successors live bitmaps if all their
4818 predecessors have been visited already. */
4819 FOR_EACH_EDGE (e, ei, bb->succs)
4820 if (last_rpo[e->dest->index] == i
4821 && live[e->dest->index])
4823 sbitmap_free (live[e->dest->index]);
4824 live[e->dest->index] = NULL;
4829 XDELETEVEC (bb_rpo);
4830 XDELETEVEC (last_rpo);
4831 for (i = 0; i < last_basic_block + NUM_FIXED_BLOCKS; ++i)
4833 sbitmap_free (live[i]);
4836 return need_asserts;
4839 /* Create an ASSERT_EXPR for NAME and insert it in the location
4840 indicated by LOC. Return true if we made any edge insertions. */
4843 process_assert_insertions_for (tree name, assert_locus_t loc)
4845 /* Build the comparison expression NAME_i COMP_CODE VAL. */
4852 cond = build2 (loc->comp_code, boolean_type_node, loc->expr, loc->val);
4853 assert_stmt = build_assert_expr_for (cond, name);
4856 /* We have been asked to insert the assertion on an edge. This
4857 is used only by COND_EXPR and SWITCH_EXPR assertions. */
4858 #if defined ENABLE_CHECKING
4859 gcc_assert (gimple_code (gsi_stmt (loc->si)) == GIMPLE_COND
4860 || gimple_code (gsi_stmt (loc->si)) == GIMPLE_SWITCH);
4863 gsi_insert_on_edge (loc->e, assert_stmt);
4867 /* Otherwise, we can insert right after LOC->SI iff the
4868 statement must not be the last statement in the block. */
4869 stmt = gsi_stmt (loc->si);
4870 if (!stmt_ends_bb_p (stmt))
4872 gsi_insert_after (&loc->si, assert_stmt, GSI_SAME_STMT);
4876 /* If STMT must be the last statement in BB, we can only insert new
4877 assertions on the non-abnormal edge out of BB. Note that since
4878 STMT is not control flow, there may only be one non-abnormal edge
4880 FOR_EACH_EDGE (e, ei, loc->bb->succs)
4881 if (!(e->flags & EDGE_ABNORMAL))
4883 gsi_insert_on_edge (e, assert_stmt);
4891 /* Process all the insertions registered for every name N_i registered
4892 in NEED_ASSERT_FOR. The list of assertions to be inserted are
4893 found in ASSERTS_FOR[i]. */
4896 process_assert_insertions (void)
4900 bool update_edges_p = false;
4901 int num_asserts = 0;
4903 if (dump_file && (dump_flags & TDF_DETAILS))
4904 dump_all_asserts (dump_file);
4906 EXECUTE_IF_SET_IN_BITMAP (need_assert_for, 0, i, bi)
4908 assert_locus_t loc = asserts_for[i];
4913 assert_locus_t next = loc->next;
4914 update_edges_p |= process_assert_insertions_for (ssa_name (i), loc);
4922 gsi_commit_edge_inserts ();
4924 statistics_counter_event (cfun, "Number of ASSERT_EXPR expressions inserted",
4929 /* Traverse the flowgraph looking for conditional jumps to insert range
4930 expressions. These range expressions are meant to provide information
4931 to optimizations that need to reason in terms of value ranges. They
4932 will not be expanded into RTL. For instance, given:
4941 this pass will transform the code into:
4947 x = ASSERT_EXPR <x, x < y>
4952 y = ASSERT_EXPR <y, x <= y>
4956 The idea is that once copy and constant propagation have run, other
4957 optimizations will be able to determine what ranges of values can 'x'
4958 take in different paths of the code, simply by checking the reaching
4959 definition of 'x'. */
4962 insert_range_assertions (void)
4964 need_assert_for = BITMAP_ALLOC (NULL);
4965 asserts_for = XCNEWVEC (assert_locus_t, num_ssa_names);
4967 calculate_dominance_info (CDI_DOMINATORS);
4969 if (find_assert_locations ())
4971 process_assert_insertions ();
4972 update_ssa (TODO_update_ssa_no_phi);
4975 if (dump_file && (dump_flags & TDF_DETAILS))
4977 fprintf (dump_file, "\nSSA form after inserting ASSERT_EXPRs\n");
4978 dump_function_to_file (current_function_decl, dump_file, dump_flags);
4982 BITMAP_FREE (need_assert_for);
4985 /* Checks one ARRAY_REF in REF, located at LOCUS. Ignores flexible arrays
4986 and "struct" hacks. If VRP can determine that the
4987 array subscript is a constant, check if it is outside valid
4988 range. If the array subscript is a RANGE, warn if it is
4989 non-overlapping with valid range.
4990 IGNORE_OFF_BY_ONE is true if the ARRAY_REF is inside a ADDR_EXPR. */
4993 check_array_ref (tree ref, location_t location, bool ignore_off_by_one)
4995 value_range_t* vr = NULL;
4996 tree low_sub, up_sub;
4997 tree low_bound, up_bound = array_ref_up_bound (ref);
4999 low_sub = up_sub = TREE_OPERAND (ref, 1);
5001 if (!up_bound || TREE_NO_WARNING (ref)
5002 || TREE_CODE (up_bound) != INTEGER_CST
5003 /* Can not check flexible arrays. */
5004 || (TYPE_SIZE (TREE_TYPE (ref)) == NULL_TREE
5005 && TYPE_DOMAIN (TREE_TYPE (ref)) != NULL_TREE
5006 && TYPE_MAX_VALUE (TYPE_DOMAIN (TREE_TYPE (ref))) == NULL_TREE)
5007 /* Accesses after the end of arrays of size 0 (gcc
5008 extension) and 1 are likely intentional ("struct
5010 || compare_tree_int (up_bound, 1) <= 0)
5013 low_bound = array_ref_low_bound (ref);
5015 if (TREE_CODE (low_sub) == SSA_NAME)
5017 vr = get_value_range (low_sub);
5018 if (vr->type == VR_RANGE || vr->type == VR_ANTI_RANGE)
5020 low_sub = vr->type == VR_RANGE ? vr->max : vr->min;
5021 up_sub = vr->type == VR_RANGE ? vr->min : vr->max;
5025 if (vr && vr->type == VR_ANTI_RANGE)
5027 if (TREE_CODE (up_sub) == INTEGER_CST
5028 && tree_int_cst_lt (up_bound, up_sub)
5029 && TREE_CODE (low_sub) == INTEGER_CST
5030 && tree_int_cst_lt (low_sub, low_bound))
5032 warning_at (location, OPT_Warray_bounds,
5033 "array subscript is outside array bounds");
5034 TREE_NO_WARNING (ref) = 1;
5037 else if (TREE_CODE (up_sub) == INTEGER_CST
5038 && tree_int_cst_lt (up_bound, up_sub)
5039 && !tree_int_cst_equal (up_bound, up_sub)
5040 && (!ignore_off_by_one
5041 || !tree_int_cst_equal (int_const_binop (PLUS_EXPR,
5047 warning_at (location, OPT_Warray_bounds,
5048 "array subscript is above array bounds");
5049 TREE_NO_WARNING (ref) = 1;
5051 else if (TREE_CODE (low_sub) == INTEGER_CST
5052 && tree_int_cst_lt (low_sub, low_bound))
5054 warning_at (location, OPT_Warray_bounds,
5055 "array subscript is below array bounds");
5056 TREE_NO_WARNING (ref) = 1;
5060 /* Searches if the expr T, located at LOCATION computes
5061 address of an ARRAY_REF, and call check_array_ref on it. */
5064 search_for_addr_array (tree t, location_t location)
5066 while (TREE_CODE (t) == SSA_NAME)
5068 gimple g = SSA_NAME_DEF_STMT (t);
5070 if (gimple_code (g) != GIMPLE_ASSIGN)
5073 if (get_gimple_rhs_class (gimple_assign_rhs_code (g))
5074 != GIMPLE_SINGLE_RHS)
5077 t = gimple_assign_rhs1 (g);
5081 /* We are only interested in addresses of ARRAY_REF's. */
5082 if (TREE_CODE (t) != ADDR_EXPR)
5085 /* Check each ARRAY_REFs in the reference chain. */
5088 if (TREE_CODE (t) == ARRAY_REF)
5089 check_array_ref (t, location, true /*ignore_off_by_one*/);
5091 t = TREE_OPERAND (t, 0);
5093 while (handled_component_p (t));
5096 /* walk_tree() callback that checks if *TP is
5097 an ARRAY_REF inside an ADDR_EXPR (in which an array
5098 subscript one outside the valid range is allowed). Call
5099 check_array_ref for each ARRAY_REF found. The location is
5103 check_array_bounds (tree *tp, int *walk_subtree, void *data)
5106 struct walk_stmt_info *wi = (struct walk_stmt_info *) data;
5107 const location_t *location = (const location_t *) wi->info;
5109 *walk_subtree = TRUE;
5111 if (TREE_CODE (t) == ARRAY_REF)
5112 check_array_ref (t, *location, false /*ignore_off_by_one*/);
5114 if (TREE_CODE (t) == INDIRECT_REF
5115 || (TREE_CODE (t) == RETURN_EXPR && TREE_OPERAND (t, 0)))
5116 search_for_addr_array (TREE_OPERAND (t, 0), *location);
5118 if (TREE_CODE (t) == ADDR_EXPR)
5119 *walk_subtree = FALSE;
5124 /* Walk over all statements of all reachable BBs and call check_array_bounds
5128 check_all_array_refs (void)
5131 gimple_stmt_iterator si;
5135 /* Skip bb's that are clearly unreachable. */
5136 if (single_pred_p (bb))
5139 bool reachable = true;
5141 edge e = EDGE_PRED (bb, 0);
5142 basic_block pred_bb = e->src;
5145 for (i = 0; VEC_iterate (edge, to_remove_edges, i, e2); ++i)
5155 if (!gsi_end_p (gsi_last_bb (pred_bb)))
5156 ls = gsi_stmt (gsi_last_bb (pred_bb));
5158 if (ls && gimple_code (ls) == GIMPLE_COND
5159 && ((gimple_cond_false_p (ls)
5160 && (EDGE_PRED (bb, 0)->flags & EDGE_TRUE_VALUE))
5161 || (gimple_cond_true_p (ls)
5162 && (EDGE_PRED (bb, 0)->flags & EDGE_FALSE_VALUE))))
5165 for (si = gsi_start_bb (bb); !gsi_end_p (si); gsi_next (&si))
5167 gimple stmt = gsi_stmt (si);
5168 struct walk_stmt_info wi;
5169 if (!gimple_has_location (stmt))
5172 if (is_gimple_call (stmt))
5175 size_t n = gimple_call_num_args (stmt);
5176 for (i = 0; i < n; i++)
5178 tree arg = gimple_call_arg (stmt, i);
5179 search_for_addr_array (arg, gimple_location (stmt));
5184 memset (&wi, 0, sizeof (wi));
5185 wi.info = CONST_CAST (void *, (const void *)
5186 gimple_location_ptr (stmt));
5188 walk_gimple_op (gsi_stmt (si),
5196 /* Convert range assertion expressions into the implied copies and
5197 copy propagate away the copies. Doing the trivial copy propagation
5198 here avoids the need to run the full copy propagation pass after
5201 FIXME, this will eventually lead to copy propagation removing the
5202 names that had useful range information attached to them. For
5203 instance, if we had the assertion N_i = ASSERT_EXPR <N_j, N_j > 3>,
5204 then N_i will have the range [3, +INF].
5206 However, by converting the assertion into the implied copy
5207 operation N_i = N_j, we will then copy-propagate N_j into the uses
5208 of N_i and lose the range information. We may want to hold on to
5209 ASSERT_EXPRs a little while longer as the ranges could be used in
5210 things like jump threading.
5212 The problem with keeping ASSERT_EXPRs around is that passes after
5213 VRP need to handle them appropriately.
5215 Another approach would be to make the range information a first
5216 class property of the SSA_NAME so that it can be queried from
5217 any pass. This is made somewhat more complex by the need for
5218 multiple ranges to be associated with one SSA_NAME. */
5221 remove_range_assertions (void)
5224 gimple_stmt_iterator si;
5226 /* Note that the BSI iterator bump happens at the bottom of the
5227 loop and no bump is necessary if we're removing the statement
5228 referenced by the current BSI. */
5230 for (si = gsi_start_bb (bb); !gsi_end_p (si);)
5232 gimple stmt = gsi_stmt (si);
5235 if (is_gimple_assign (stmt)
5236 && gimple_assign_rhs_code (stmt) == ASSERT_EXPR)
5238 tree rhs = gimple_assign_rhs1 (stmt);
5240 tree cond = fold (ASSERT_EXPR_COND (rhs));
5241 use_operand_p use_p;
5242 imm_use_iterator iter;
5244 gcc_assert (cond != boolean_false_node);
5246 /* Propagate the RHS into every use of the LHS. */
5247 var = ASSERT_EXPR_VAR (rhs);
5248 FOR_EACH_IMM_USE_STMT (use_stmt, iter,
5249 gimple_assign_lhs (stmt))
5250 FOR_EACH_IMM_USE_ON_STMT (use_p, iter)
5252 SET_USE (use_p, var);
5253 gcc_assert (TREE_CODE (var) == SSA_NAME);
5256 /* And finally, remove the copy, it is not needed. */
5257 gsi_remove (&si, true);
5258 release_defs (stmt);
5266 /* Return true if STMT is interesting for VRP. */
5269 stmt_interesting_for_vrp (gimple stmt)
5271 if (gimple_code (stmt) == GIMPLE_PHI
5272 && is_gimple_reg (gimple_phi_result (stmt))
5273 && (INTEGRAL_TYPE_P (TREE_TYPE (gimple_phi_result (stmt)))
5274 || POINTER_TYPE_P (TREE_TYPE (gimple_phi_result (stmt)))))
5276 else if (is_gimple_assign (stmt) || is_gimple_call (stmt))
5278 tree lhs = gimple_get_lhs (stmt);
5280 /* In general, assignments with virtual operands are not useful
5281 for deriving ranges, with the obvious exception of calls to
5282 builtin functions. */
5283 if (lhs && TREE_CODE (lhs) == SSA_NAME
5284 && (INTEGRAL_TYPE_P (TREE_TYPE (lhs))
5285 || POINTER_TYPE_P (TREE_TYPE (lhs)))
5286 && ((is_gimple_call (stmt)
5287 && gimple_call_fndecl (stmt) != NULL_TREE
5288 && DECL_IS_BUILTIN (gimple_call_fndecl (stmt)))
5289 || !gimple_vuse (stmt)))
5292 else if (gimple_code (stmt) == GIMPLE_COND
5293 || gimple_code (stmt) == GIMPLE_SWITCH)
5300 /* Initialize local data structures for VRP. */
5303 vrp_initialize (void)
5307 vr_value = XCNEWVEC (value_range_t *, num_ssa_names);
5308 vr_phi_edge_counts = XCNEWVEC (int, num_ssa_names);
5312 gimple_stmt_iterator si;
5314 for (si = gsi_start_phis (bb); !gsi_end_p (si); gsi_next (&si))
5316 gimple phi = gsi_stmt (si);
5317 if (!stmt_interesting_for_vrp (phi))
5319 tree lhs = PHI_RESULT (phi);
5320 set_value_range_to_varying (get_value_range (lhs));
5321 prop_set_simulate_again (phi, false);
5324 prop_set_simulate_again (phi, true);
5327 for (si = gsi_start_bb (bb); !gsi_end_p (si); gsi_next (&si))
5329 gimple stmt = gsi_stmt (si);
5331 if (!stmt_interesting_for_vrp (stmt))
5335 FOR_EACH_SSA_TREE_OPERAND (def, stmt, i, SSA_OP_DEF)
5336 set_value_range_to_varying (get_value_range (def));
5337 prop_set_simulate_again (stmt, false);
5341 prop_set_simulate_again (stmt, true);
5348 /* Visit assignment STMT. If it produces an interesting range, record
5349 the SSA name in *OUTPUT_P. */
5351 static enum ssa_prop_result
5352 vrp_visit_assignment_or_call (gimple stmt, tree *output_p)
5356 enum gimple_code code = gimple_code (stmt);
5357 lhs = gimple_get_lhs (stmt);
5359 /* We only keep track of ranges in integral and pointer types. */
5360 if (TREE_CODE (lhs) == SSA_NAME
5361 && ((INTEGRAL_TYPE_P (TREE_TYPE (lhs))
5362 /* It is valid to have NULL MIN/MAX values on a type. See
5363 build_range_type. */
5364 && TYPE_MIN_VALUE (TREE_TYPE (lhs))
5365 && TYPE_MAX_VALUE (TREE_TYPE (lhs)))
5366 || POINTER_TYPE_P (TREE_TYPE (lhs))))
5369 value_range_t new_vr = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
5371 if (code == GIMPLE_CALL)
5372 extract_range_basic (&new_vr, stmt);
5374 extract_range_from_assignment (&new_vr, stmt);
5376 /* If STMT is inside a loop, we may be able to know something
5377 else about the range of LHS by examining scalar evolution
5379 if (current_loops && (l = loop_containing_stmt (stmt)))
5380 adjust_range_with_scev (&new_vr, l, stmt, lhs);
5382 if (update_value_range (lhs, &new_vr))
5386 if (dump_file && (dump_flags & TDF_DETAILS))
5388 fprintf (dump_file, "Found new range for ");
5389 print_generic_expr (dump_file, lhs, 0);
5390 fprintf (dump_file, ": ");
5391 dump_value_range (dump_file, &new_vr);
5392 fprintf (dump_file, "\n\n");
5395 if (new_vr.type == VR_VARYING)
5396 return SSA_PROP_VARYING;
5398 return SSA_PROP_INTERESTING;
5401 return SSA_PROP_NOT_INTERESTING;
5404 /* Every other statement produces no useful ranges. */
5405 FOR_EACH_SSA_TREE_OPERAND (def, stmt, iter, SSA_OP_DEF)
5406 set_value_range_to_varying (get_value_range (def));
5408 return SSA_PROP_VARYING;
5411 /* Helper that gets the value range of the SSA_NAME with version I
5412 or a symbolic range containing the SSA_NAME only if the value range
5413 is varying or undefined. */
5415 static inline value_range_t
5416 get_vr_for_comparison (int i)
5418 value_range_t vr = *(vr_value[i]);
5420 /* If name N_i does not have a valid range, use N_i as its own
5421 range. This allows us to compare against names that may
5422 have N_i in their ranges. */
5423 if (vr.type == VR_VARYING || vr.type == VR_UNDEFINED)
5426 vr.min = ssa_name (i);
5427 vr.max = ssa_name (i);
5433 /* Compare all the value ranges for names equivalent to VAR with VAL
5434 using comparison code COMP. Return the same value returned by
5435 compare_range_with_value, including the setting of
5436 *STRICT_OVERFLOW_P. */
5439 compare_name_with_value (enum tree_code comp, tree var, tree val,
5440 bool *strict_overflow_p)
5446 int used_strict_overflow;
5448 value_range_t equiv_vr;
5450 /* Get the set of equivalences for VAR. */
5451 e = get_value_range (var)->equiv;
5453 /* Start at -1. Set it to 0 if we do a comparison without relying
5454 on overflow, or 1 if all comparisons rely on overflow. */
5455 used_strict_overflow = -1;
5457 /* Compare vars' value range with val. */
5458 equiv_vr = get_vr_for_comparison (SSA_NAME_VERSION (var));
5460 retval = compare_range_with_value (comp, &equiv_vr, val, &sop);
5462 used_strict_overflow = sop ? 1 : 0;
5464 /* If the equiv set is empty we have done all work we need to do. */
5468 && used_strict_overflow > 0)
5469 *strict_overflow_p = true;
5473 EXECUTE_IF_SET_IN_BITMAP (e, 0, i, bi)
5475 equiv_vr = get_vr_for_comparison (i);
5477 t = compare_range_with_value (comp, &equiv_vr, val, &sop);
5480 /* If we get different answers from different members
5481 of the equivalence set this check must be in a dead
5482 code region. Folding it to a trap representation
5483 would be correct here. For now just return don't-know. */
5493 used_strict_overflow = 0;
5494 else if (used_strict_overflow < 0)
5495 used_strict_overflow = 1;
5500 && used_strict_overflow > 0)
5501 *strict_overflow_p = true;
5507 /* Given a comparison code COMP and names N1 and N2, compare all the
5508 ranges equivalent to N1 against all the ranges equivalent to N2
5509 to determine the value of N1 COMP N2. Return the same value
5510 returned by compare_ranges. Set *STRICT_OVERFLOW_P to indicate
5511 whether we relied on an overflow infinity in the comparison. */
5515 compare_names (enum tree_code comp, tree n1, tree n2,
5516 bool *strict_overflow_p)
5520 bitmap_iterator bi1, bi2;
5522 int used_strict_overflow;
5523 static bitmap_obstack *s_obstack = NULL;
5524 static bitmap s_e1 = NULL, s_e2 = NULL;
5526 /* Compare the ranges of every name equivalent to N1 against the
5527 ranges of every name equivalent to N2. */
5528 e1 = get_value_range (n1)->equiv;
5529 e2 = get_value_range (n2)->equiv;
5531 /* Use the fake bitmaps if e1 or e2 are not available. */
5532 if (s_obstack == NULL)
5534 s_obstack = XNEW (bitmap_obstack);
5535 bitmap_obstack_initialize (s_obstack);
5536 s_e1 = BITMAP_ALLOC (s_obstack);
5537 s_e2 = BITMAP_ALLOC (s_obstack);
5544 /* Add N1 and N2 to their own set of equivalences to avoid
5545 duplicating the body of the loop just to check N1 and N2
5547 bitmap_set_bit (e1, SSA_NAME_VERSION (n1));
5548 bitmap_set_bit (e2, SSA_NAME_VERSION (n2));
5550 /* If the equivalence sets have a common intersection, then the two
5551 names can be compared without checking their ranges. */
5552 if (bitmap_intersect_p (e1, e2))
5554 bitmap_clear_bit (e1, SSA_NAME_VERSION (n1));
5555 bitmap_clear_bit (e2, SSA_NAME_VERSION (n2));
5557 return (comp == EQ_EXPR || comp == GE_EXPR || comp == LE_EXPR)
5559 : boolean_false_node;
5562 /* Start at -1. Set it to 0 if we do a comparison without relying
5563 on overflow, or 1 if all comparisons rely on overflow. */
5564 used_strict_overflow = -1;
5566 /* Otherwise, compare all the equivalent ranges. First, add N1 and
5567 N2 to their own set of equivalences to avoid duplicating the body
5568 of the loop just to check N1 and N2 ranges. */
5569 EXECUTE_IF_SET_IN_BITMAP (e1, 0, i1, bi1)
5571 value_range_t vr1 = get_vr_for_comparison (i1);
5573 t = retval = NULL_TREE;
5574 EXECUTE_IF_SET_IN_BITMAP (e2, 0, i2, bi2)
5578 value_range_t vr2 = get_vr_for_comparison (i2);
5580 t = compare_ranges (comp, &vr1, &vr2, &sop);
5583 /* If we get different answers from different members
5584 of the equivalence set this check must be in a dead
5585 code region. Folding it to a trap representation
5586 would be correct here. For now just return don't-know. */
5590 bitmap_clear_bit (e1, SSA_NAME_VERSION (n1));
5591 bitmap_clear_bit (e2, SSA_NAME_VERSION (n2));
5597 used_strict_overflow = 0;
5598 else if (used_strict_overflow < 0)
5599 used_strict_overflow = 1;
5605 bitmap_clear_bit (e1, SSA_NAME_VERSION (n1));
5606 bitmap_clear_bit (e2, SSA_NAME_VERSION (n2));
5607 if (used_strict_overflow > 0)
5608 *strict_overflow_p = true;
5613 /* None of the equivalent ranges are useful in computing this
5615 bitmap_clear_bit (e1, SSA_NAME_VERSION (n1));
5616 bitmap_clear_bit (e2, SSA_NAME_VERSION (n2));
5620 /* Helper function for vrp_evaluate_conditional_warnv. */
5623 vrp_evaluate_conditional_warnv_with_ops_using_ranges (enum tree_code code,
5625 bool * strict_overflow_p)
5627 value_range_t *vr0, *vr1;
5629 vr0 = (TREE_CODE (op0) == SSA_NAME) ? get_value_range (op0) : NULL;
5630 vr1 = (TREE_CODE (op1) == SSA_NAME) ? get_value_range (op1) : NULL;
5633 return compare_ranges (code, vr0, vr1, strict_overflow_p);
5634 else if (vr0 && vr1 == NULL)
5635 return compare_range_with_value (code, vr0, op1, strict_overflow_p);
5636 else if (vr0 == NULL && vr1)
5637 return (compare_range_with_value
5638 (swap_tree_comparison (code), vr1, op0, strict_overflow_p));
5642 /* Helper function for vrp_evaluate_conditional_warnv. */
5645 vrp_evaluate_conditional_warnv_with_ops (enum tree_code code, tree op0,
5646 tree op1, bool use_equiv_p,
5647 bool *strict_overflow_p, bool *only_ranges)
5651 *only_ranges = true;
5653 /* We only deal with integral and pointer types. */
5654 if (!INTEGRAL_TYPE_P (TREE_TYPE (op0))
5655 && !POINTER_TYPE_P (TREE_TYPE (op0)))
5661 && (ret = vrp_evaluate_conditional_warnv_with_ops_using_ranges
5662 (code, op0, op1, strict_overflow_p)))
5664 *only_ranges = false;
5665 if (TREE_CODE (op0) == SSA_NAME && TREE_CODE (op1) == SSA_NAME)
5666 return compare_names (code, op0, op1, strict_overflow_p);
5667 else if (TREE_CODE (op0) == SSA_NAME)
5668 return compare_name_with_value (code, op0, op1, strict_overflow_p);
5669 else if (TREE_CODE (op1) == SSA_NAME)
5670 return (compare_name_with_value
5671 (swap_tree_comparison (code), op1, op0, strict_overflow_p));
5674 return vrp_evaluate_conditional_warnv_with_ops_using_ranges (code, op0, op1,
5679 /* Given (CODE OP0 OP1) within STMT, try to simplify it based on value range
5680 information. Return NULL if the conditional can not be evaluated.
5681 The ranges of all the names equivalent with the operands in COND
5682 will be used when trying to compute the value. If the result is
5683 based on undefined signed overflow, issue a warning if
5687 vrp_evaluate_conditional (enum tree_code code, tree op0, tree op1, gimple stmt)
5694 ret = vrp_evaluate_conditional_warnv_with_ops (code, op0, op1, true, &sop,
5699 enum warn_strict_overflow_code wc;
5700 const char* warnmsg;
5702 if (is_gimple_min_invariant (ret))
5704 wc = WARN_STRICT_OVERFLOW_CONDITIONAL;
5705 warnmsg = G_("assuming signed overflow does not occur when "
5706 "simplifying conditional to constant");
5710 wc = WARN_STRICT_OVERFLOW_COMPARISON;
5711 warnmsg = G_("assuming signed overflow does not occur when "
5712 "simplifying conditional");
5715 if (issue_strict_overflow_warning (wc))
5717 location_t location;
5719 if (!gimple_has_location (stmt))
5720 location = input_location;
5722 location = gimple_location (stmt);
5723 warning (OPT_Wstrict_overflow, "%H%s", &location, warnmsg);
5727 if (warn_type_limits
5728 && ret && only_ranges
5729 && TREE_CODE_CLASS (code) == tcc_comparison
5730 && TREE_CODE (op0) == SSA_NAME)
5732 /* If the comparison is being folded and the operand on the LHS
5733 is being compared against a constant value that is outside of
5734 the natural range of OP0's type, then the predicate will
5735 always fold regardless of the value of OP0. If -Wtype-limits
5736 was specified, emit a warning. */
5737 const char *warnmsg = NULL;
5738 tree type = TREE_TYPE (op0);
5739 value_range_t *vr0 = get_value_range (op0);
5741 if (vr0->type != VR_VARYING
5742 && INTEGRAL_TYPE_P (type)
5743 && vrp_val_is_min (vr0->min)
5744 && vrp_val_is_max (vr0->max)
5745 && is_gimple_min_invariant (op1))
5747 if (integer_zerop (ret))
5748 warnmsg = G_("comparison always false due to limited range of "
5751 warnmsg = G_("comparison always true due to limited range of "
5757 location_t location;
5759 if (!gimple_has_location (stmt))
5760 location = input_location;
5762 location = gimple_location (stmt);
5764 warning (OPT_Wtype_limits, "%H%s", &location, warnmsg);
5772 /* Visit conditional statement STMT. If we can determine which edge
5773 will be taken out of STMT's basic block, record it in
5774 *TAKEN_EDGE_P and return SSA_PROP_INTERESTING. Otherwise, return
5775 SSA_PROP_VARYING. */
5777 static enum ssa_prop_result
5778 vrp_visit_cond_stmt (gimple stmt, edge *taken_edge_p)
5783 *taken_edge_p = NULL;
5785 if (dump_file && (dump_flags & TDF_DETAILS))
5790 fprintf (dump_file, "\nVisiting conditional with predicate: ");
5791 print_gimple_stmt (dump_file, stmt, 0, 0);
5792 fprintf (dump_file, "\nWith known ranges\n");
5794 FOR_EACH_SSA_TREE_OPERAND (use, stmt, i, SSA_OP_USE)
5796 fprintf (dump_file, "\t");
5797 print_generic_expr (dump_file, use, 0);
5798 fprintf (dump_file, ": ");
5799 dump_value_range (dump_file, vr_value[SSA_NAME_VERSION (use)]);
5802 fprintf (dump_file, "\n");
5805 /* Compute the value of the predicate COND by checking the known
5806 ranges of each of its operands.
5808 Note that we cannot evaluate all the equivalent ranges here
5809 because those ranges may not yet be final and with the current
5810 propagation strategy, we cannot determine when the value ranges
5811 of the names in the equivalence set have changed.
5813 For instance, given the following code fragment
5817 i_14 = ASSERT_EXPR <i_5, i_5 != 0>
5821 Assume that on the first visit to i_14, i_5 has the temporary
5822 range [8, 8] because the second argument to the PHI function is
5823 not yet executable. We derive the range ~[0, 0] for i_14 and the
5824 equivalence set { i_5 }. So, when we visit 'if (i_14 == 1)' for
5825 the first time, since i_14 is equivalent to the range [8, 8], we
5826 determine that the predicate is always false.
5828 On the next round of propagation, i_13 is determined to be
5829 VARYING, which causes i_5 to drop down to VARYING. So, another
5830 visit to i_14 is scheduled. In this second visit, we compute the
5831 exact same range and equivalence set for i_14, namely ~[0, 0] and
5832 { i_5 }. But we did not have the previous range for i_5
5833 registered, so vrp_visit_assignment thinks that the range for
5834 i_14 has not changed. Therefore, the predicate 'if (i_14 == 1)'
5835 is not visited again, which stops propagation from visiting
5836 statements in the THEN clause of that if().
5838 To properly fix this we would need to keep the previous range
5839 value for the names in the equivalence set. This way we would've
5840 discovered that from one visit to the other i_5 changed from
5841 range [8, 8] to VR_VARYING.
5843 However, fixing this apparent limitation may not be worth the
5844 additional checking. Testing on several code bases (GCC, DLV,
5845 MICO, TRAMP3D and SPEC2000) showed that doing this results in
5846 4 more predicates folded in SPEC. */
5849 val = vrp_evaluate_conditional_warnv_with_ops (gimple_cond_code (stmt),
5850 gimple_cond_lhs (stmt),
5851 gimple_cond_rhs (stmt),
5856 *taken_edge_p = find_taken_edge (gimple_bb (stmt), val);
5859 if (dump_file && (dump_flags & TDF_DETAILS))
5861 "\nIgnoring predicate evaluation because "
5862 "it assumes that signed overflow is undefined");
5867 if (dump_file && (dump_flags & TDF_DETAILS))
5869 fprintf (dump_file, "\nPredicate evaluates to: ");
5870 if (val == NULL_TREE)
5871 fprintf (dump_file, "DON'T KNOW\n");
5873 print_generic_stmt (dump_file, val, 0);
5876 return (*taken_edge_p) ? SSA_PROP_INTERESTING : SSA_PROP_VARYING;
5879 /* Searches the case label vector VEC for the index *IDX of the CASE_LABEL
5880 that includes the value VAL. The search is restricted to the range
5881 [START_IDX, n - 1] where n is the size of VEC.
5883 If there is a CASE_LABEL for VAL, its index is placed in IDX and true is
5886 If there is no CASE_LABEL for VAL and there is one that is larger than VAL,
5887 it is placed in IDX and false is returned.
5889 If VAL is larger than any CASE_LABEL, n is placed on IDX and false is
5893 find_case_label_index (gimple stmt, size_t start_idx, tree val, size_t *idx)
5895 size_t n = gimple_switch_num_labels (stmt);
5898 /* Find case label for minimum of the value range or the next one.
5899 At each iteration we are searching in [low, high - 1]. */
5901 for (low = start_idx, high = n; high != low; )
5905 /* Note that i != high, so we never ask for n. */
5906 size_t i = (high + low) / 2;
5907 t = gimple_switch_label (stmt, i);
5909 /* Cache the result of comparing CASE_LOW and val. */
5910 cmp = tree_int_cst_compare (CASE_LOW (t), val);
5914 /* Ranges cannot be empty. */
5923 if (CASE_HIGH (t) != NULL
5924 && tree_int_cst_compare (CASE_HIGH (t), val) >= 0)
5936 /* Searches the case label vector VEC for the range of CASE_LABELs that is used
5937 for values between MIN and MAX. The first index is placed in MIN_IDX. The
5938 last index is placed in MAX_IDX. If the range of CASE_LABELs is empty
5939 then MAX_IDX < MIN_IDX.
5940 Returns true if the default label is not needed. */
5943 find_case_label_range (gimple stmt, tree min, tree max, size_t *min_idx,
5947 bool min_take_default = !find_case_label_index (stmt, 1, min, &i);
5948 bool max_take_default = !find_case_label_index (stmt, i, max, &j);
5952 && max_take_default)
5954 /* Only the default case label reached.
5955 Return an empty range. */
5962 bool take_default = min_take_default || max_take_default;
5966 if (max_take_default)
5969 /* If the case label range is continuous, we do not need
5970 the default case label. Verify that. */
5971 high = CASE_LOW (gimple_switch_label (stmt, i));
5972 if (CASE_HIGH (gimple_switch_label (stmt, i)))
5973 high = CASE_HIGH (gimple_switch_label (stmt, i));
5974 for (k = i + 1; k <= j; ++k)
5976 low = CASE_LOW (gimple_switch_label (stmt, k));
5977 if (!integer_onep (int_const_binop (MINUS_EXPR, low, high, 0)))
5979 take_default = true;
5983 if (CASE_HIGH (gimple_switch_label (stmt, k)))
5984 high = CASE_HIGH (gimple_switch_label (stmt, k));
5989 return !take_default;
5993 /* Visit switch statement STMT. If we can determine which edge
5994 will be taken out of STMT's basic block, record it in
5995 *TAKEN_EDGE_P and return SSA_PROP_INTERESTING. Otherwise, return
5996 SSA_PROP_VARYING. */
5998 static enum ssa_prop_result
5999 vrp_visit_switch_stmt (gimple stmt, edge *taken_edge_p)
6003 size_t i = 0, j = 0, n;
6006 *taken_edge_p = NULL;
6007 op = gimple_switch_index (stmt);
6008 if (TREE_CODE (op) != SSA_NAME)
6009 return SSA_PROP_VARYING;
6011 vr = get_value_range (op);
6012 if (dump_file && (dump_flags & TDF_DETAILS))
6014 fprintf (dump_file, "\nVisiting switch expression with operand ");
6015 print_generic_expr (dump_file, op, 0);
6016 fprintf (dump_file, " with known range ");
6017 dump_value_range (dump_file, vr);
6018 fprintf (dump_file, "\n");
6021 if (vr->type != VR_RANGE
6022 || symbolic_range_p (vr))
6023 return SSA_PROP_VARYING;
6025 /* Find the single edge that is taken from the switch expression. */
6026 n = gimple_switch_num_labels (stmt);
6028 take_default = !find_case_label_range (stmt, vr->min, vr->max, &i, &j);
6030 /* Check if the range spans no CASE_LABEL. If so, we only reach the default
6034 gcc_assert (take_default);
6035 val = gimple_switch_default_label (stmt);
6039 /* Check if labels with index i to j and maybe the default label
6040 are all reaching the same label. */
6042 val = gimple_switch_label (stmt, i);
6044 && CASE_LABEL (gimple_switch_default_label (stmt))
6045 != CASE_LABEL (val))
6047 if (dump_file && (dump_flags & TDF_DETAILS))
6048 fprintf (dump_file, " not a single destination for this "
6050 return SSA_PROP_VARYING;
6052 for (++i; i <= j; ++i)
6054 if (CASE_LABEL (gimple_switch_label (stmt, i)) != CASE_LABEL (val))
6056 if (dump_file && (dump_flags & TDF_DETAILS))
6057 fprintf (dump_file, " not a single destination for this "
6059 return SSA_PROP_VARYING;
6064 *taken_edge_p = find_edge (gimple_bb (stmt),
6065 label_to_block (CASE_LABEL (val)));
6067 if (dump_file && (dump_flags & TDF_DETAILS))
6069 fprintf (dump_file, " will take edge to ");
6070 print_generic_stmt (dump_file, CASE_LABEL (val), 0);
6073 return SSA_PROP_INTERESTING;
6077 /* Evaluate statement STMT. If the statement produces a useful range,
6078 return SSA_PROP_INTERESTING and record the SSA name with the
6079 interesting range into *OUTPUT_P.
6081 If STMT is a conditional branch and we can determine its truth
6082 value, the taken edge is recorded in *TAKEN_EDGE_P.
6084 If STMT produces a varying value, return SSA_PROP_VARYING. */
6086 static enum ssa_prop_result
6087 vrp_visit_stmt (gimple stmt, edge *taken_edge_p, tree *output_p)
6092 if (dump_file && (dump_flags & TDF_DETAILS))
6094 fprintf (dump_file, "\nVisiting statement:\n");
6095 print_gimple_stmt (dump_file, stmt, 0, dump_flags);
6096 fprintf (dump_file, "\n");
6099 if (is_gimple_assign (stmt) || is_gimple_call (stmt))
6101 /* In general, assignments with virtual operands are not useful
6102 for deriving ranges, with the obvious exception of calls to
6103 builtin functions. */
6105 if ((is_gimple_call (stmt)
6106 && gimple_call_fndecl (stmt) != NULL_TREE
6107 && DECL_IS_BUILTIN (gimple_call_fndecl (stmt)))
6108 || !gimple_vuse (stmt))
6109 return vrp_visit_assignment_or_call (stmt, output_p);
6111 else if (gimple_code (stmt) == GIMPLE_COND)
6112 return vrp_visit_cond_stmt (stmt, taken_edge_p);
6113 else if (gimple_code (stmt) == GIMPLE_SWITCH)
6114 return vrp_visit_switch_stmt (stmt, taken_edge_p);
6116 /* All other statements produce nothing of interest for VRP, so mark
6117 their outputs varying and prevent further simulation. */
6118 FOR_EACH_SSA_TREE_OPERAND (def, stmt, iter, SSA_OP_DEF)
6119 set_value_range_to_varying (get_value_range (def));
6121 return SSA_PROP_VARYING;
6125 /* Meet operation for value ranges. Given two value ranges VR0 and
6126 VR1, store in VR0 a range that contains both VR0 and VR1. This
6127 may not be the smallest possible such range. */
6130 vrp_meet (value_range_t *vr0, value_range_t *vr1)
6132 if (vr0->type == VR_UNDEFINED)
6134 copy_value_range (vr0, vr1);
6138 if (vr1->type == VR_UNDEFINED)
6140 /* Nothing to do. VR0 already has the resulting range. */
6144 if (vr0->type == VR_VARYING)
6146 /* Nothing to do. VR0 already has the resulting range. */
6150 if (vr1->type == VR_VARYING)
6152 set_value_range_to_varying (vr0);
6156 if (vr0->type == VR_RANGE && vr1->type == VR_RANGE)
6161 /* Compute the convex hull of the ranges. The lower limit of
6162 the new range is the minimum of the two ranges. If they
6163 cannot be compared, then give up. */
6164 cmp = compare_values (vr0->min, vr1->min);
6165 if (cmp == 0 || cmp == 1)
6172 /* Similarly, the upper limit of the new range is the maximum
6173 of the two ranges. If they cannot be compared, then
6175 cmp = compare_values (vr0->max, vr1->max);
6176 if (cmp == 0 || cmp == -1)
6183 /* Check for useless ranges. */
6184 if (INTEGRAL_TYPE_P (TREE_TYPE (min))
6185 && ((vrp_val_is_min (min) || is_overflow_infinity (min))
6186 && (vrp_val_is_max (max) || is_overflow_infinity (max))))
6189 /* The resulting set of equivalences is the intersection of
6191 if (vr0->equiv && vr1->equiv && vr0->equiv != vr1->equiv)
6192 bitmap_and_into (vr0->equiv, vr1->equiv);
6193 else if (vr0->equiv && !vr1->equiv)
6194 bitmap_clear (vr0->equiv);
6196 set_value_range (vr0, vr0->type, min, max, vr0->equiv);
6198 else if (vr0->type == VR_ANTI_RANGE && vr1->type == VR_ANTI_RANGE)
6200 /* Two anti-ranges meet only if their complements intersect.
6201 Only handle the case of identical ranges. */
6202 if (compare_values (vr0->min, vr1->min) == 0
6203 && compare_values (vr0->max, vr1->max) == 0
6204 && compare_values (vr0->min, vr0->max) == 0)
6206 /* The resulting set of equivalences is the intersection of
6208 if (vr0->equiv && vr1->equiv && vr0->equiv != vr1->equiv)
6209 bitmap_and_into (vr0->equiv, vr1->equiv);
6210 else if (vr0->equiv && !vr1->equiv)
6211 bitmap_clear (vr0->equiv);
6216 else if (vr0->type == VR_ANTI_RANGE || vr1->type == VR_ANTI_RANGE)
6218 /* For a numeric range [VAL1, VAL2] and an anti-range ~[VAL3, VAL4],
6219 only handle the case where the ranges have an empty intersection.
6220 The result of the meet operation is the anti-range. */
6221 if (!symbolic_range_p (vr0)
6222 && !symbolic_range_p (vr1)
6223 && !value_ranges_intersect_p (vr0, vr1))
6225 /* Copy most of VR1 into VR0. Don't copy VR1's equivalence
6226 set. We need to compute the intersection of the two
6227 equivalence sets. */
6228 if (vr1->type == VR_ANTI_RANGE)
6229 set_value_range (vr0, vr1->type, vr1->min, vr1->max, vr0->equiv);
6231 /* The resulting set of equivalences is the intersection of
6233 if (vr0->equiv && vr1->equiv && vr0->equiv != vr1->equiv)
6234 bitmap_and_into (vr0->equiv, vr1->equiv);
6235 else if (vr0->equiv && !vr1->equiv)
6236 bitmap_clear (vr0->equiv);
6247 /* Failed to find an efficient meet. Before giving up and setting
6248 the result to VARYING, see if we can at least derive a useful
6249 anti-range. FIXME, all this nonsense about distinguishing
6250 anti-ranges from ranges is necessary because of the odd
6251 semantics of range_includes_zero_p and friends. */
6252 if (!symbolic_range_p (vr0)
6253 && ((vr0->type == VR_RANGE && !range_includes_zero_p (vr0))
6254 || (vr0->type == VR_ANTI_RANGE && range_includes_zero_p (vr0)))
6255 && !symbolic_range_p (vr1)
6256 && ((vr1->type == VR_RANGE && !range_includes_zero_p (vr1))
6257 || (vr1->type == VR_ANTI_RANGE && range_includes_zero_p (vr1))))
6259 set_value_range_to_nonnull (vr0, TREE_TYPE (vr0->min));
6261 /* Since this meet operation did not result from the meeting of
6262 two equivalent names, VR0 cannot have any equivalences. */
6264 bitmap_clear (vr0->equiv);
6267 set_value_range_to_varying (vr0);
6271 /* Visit all arguments for PHI node PHI that flow through executable
6272 edges. If a valid value range can be derived from all the incoming
6273 value ranges, set a new range for the LHS of PHI. */
6275 static enum ssa_prop_result
6276 vrp_visit_phi_node (gimple phi)
6279 tree lhs = PHI_RESULT (phi);
6280 value_range_t *lhs_vr = get_value_range (lhs);
6281 value_range_t vr_result = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
6282 int edges, old_edges;
6284 copy_value_range (&vr_result, lhs_vr);
6286 if (dump_file && (dump_flags & TDF_DETAILS))
6288 fprintf (dump_file, "\nVisiting PHI node: ");
6289 print_gimple_stmt (dump_file, phi, 0, dump_flags);
6293 for (i = 0; i < gimple_phi_num_args (phi); i++)
6295 edge e = gimple_phi_arg_edge (phi, i);
6297 if (dump_file && (dump_flags & TDF_DETAILS))
6300 "\n Argument #%d (%d -> %d %sexecutable)\n",
6301 (int) i, e->src->index, e->dest->index,
6302 (e->flags & EDGE_EXECUTABLE) ? "" : "not ");
6305 if (e->flags & EDGE_EXECUTABLE)
6307 tree arg = PHI_ARG_DEF (phi, i);
6308 value_range_t vr_arg;
6312 if (TREE_CODE (arg) == SSA_NAME)
6314 vr_arg = *(get_value_range (arg));
6318 if (is_overflow_infinity (arg))
6320 arg = copy_node (arg);
6321 TREE_OVERFLOW (arg) = 0;
6324 vr_arg.type = VR_RANGE;
6327 vr_arg.equiv = NULL;
6330 if (dump_file && (dump_flags & TDF_DETAILS))
6332 fprintf (dump_file, "\t");
6333 print_generic_expr (dump_file, arg, dump_flags);
6334 fprintf (dump_file, "\n\tValue: ");
6335 dump_value_range (dump_file, &vr_arg);
6336 fprintf (dump_file, "\n");
6339 vrp_meet (&vr_result, &vr_arg);
6341 if (vr_result.type == VR_VARYING)
6346 if (vr_result.type == VR_VARYING)
6349 old_edges = vr_phi_edge_counts[SSA_NAME_VERSION (lhs)];
6350 vr_phi_edge_counts[SSA_NAME_VERSION (lhs)] = edges;
6352 /* To prevent infinite iterations in the algorithm, derive ranges
6353 when the new value is slightly bigger or smaller than the
6354 previous one. We don't do this if we have seen a new executable
6355 edge; this helps us avoid an overflow infinity for conditionals
6356 which are not in a loop. */
6357 if (lhs_vr->type == VR_RANGE && vr_result.type == VR_RANGE
6358 && edges <= old_edges)
6360 if (!POINTER_TYPE_P (TREE_TYPE (lhs)))
6362 int cmp_min = compare_values (lhs_vr->min, vr_result.min);
6363 int cmp_max = compare_values (lhs_vr->max, vr_result.max);
6365 /* If the new minimum is smaller or larger than the previous
6366 one, go all the way to -INF. In the first case, to avoid
6367 iterating millions of times to reach -INF, and in the
6368 other case to avoid infinite bouncing between different
6370 if (cmp_min > 0 || cmp_min < 0)
6372 /* If we will end up with a (-INF, +INF) range, set it to
6373 VARYING. Same if the previous max value was invalid for
6374 the type and we'd end up with vr_result.min > vr_result.max. */
6375 if (vrp_val_is_max (vr_result.max)
6376 || compare_values (TYPE_MIN_VALUE (TREE_TYPE (vr_result.min)),
6380 if (!needs_overflow_infinity (TREE_TYPE (vr_result.min))
6381 || !vrp_var_may_overflow (lhs, phi))
6382 vr_result.min = TYPE_MIN_VALUE (TREE_TYPE (vr_result.min));
6383 else if (supports_overflow_infinity (TREE_TYPE (vr_result.min)))
6385 negative_overflow_infinity (TREE_TYPE (vr_result.min));
6390 /* Similarly, if the new maximum is smaller or larger than
6391 the previous one, go all the way to +INF. */
6392 if (cmp_max < 0 || cmp_max > 0)
6394 /* If we will end up with a (-INF, +INF) range, set it to
6395 VARYING. Same if the previous min value was invalid for
6396 the type and we'd end up with vr_result.max < vr_result.min. */
6397 if (vrp_val_is_min (vr_result.min)
6398 || compare_values (TYPE_MAX_VALUE (TREE_TYPE (vr_result.max)),
6402 if (!needs_overflow_infinity (TREE_TYPE (vr_result.max))
6403 || !vrp_var_may_overflow (lhs, phi))
6404 vr_result.max = TYPE_MAX_VALUE (TREE_TYPE (vr_result.max));
6405 else if (supports_overflow_infinity (TREE_TYPE (vr_result.max)))
6407 positive_overflow_infinity (TREE_TYPE (vr_result.max));
6414 /* If the new range is different than the previous value, keep
6416 if (update_value_range (lhs, &vr_result))
6417 return SSA_PROP_INTERESTING;
6419 /* Nothing changed, don't add outgoing edges. */
6420 return SSA_PROP_NOT_INTERESTING;
6422 /* No match found. Set the LHS to VARYING. */
6424 set_value_range_to_varying (lhs_vr);
6425 return SSA_PROP_VARYING;
6428 /* Simplify boolean operations if the source is known
6429 to be already a boolean. */
6431 simplify_truth_ops_using_ranges (gimple_stmt_iterator *gsi, gimple stmt)
6433 enum tree_code rhs_code = gimple_assign_rhs_code (stmt);
6438 bool need_conversion;
6440 op0 = gimple_assign_rhs1 (stmt);
6441 if (TYPE_PRECISION (TREE_TYPE (op0)) != 1)
6443 if (TREE_CODE (op0) != SSA_NAME)
6445 vr = get_value_range (op0);
6447 val = compare_range_with_value (GE_EXPR, vr, integer_zero_node, &sop);
6448 if (!val || !integer_onep (val))
6451 val = compare_range_with_value (LE_EXPR, vr, integer_one_node, &sop);
6452 if (!val || !integer_onep (val))
6456 if (rhs_code == TRUTH_NOT_EXPR)
6459 op1 = build_int_cst (TREE_TYPE (op0), 1);
6463 op1 = gimple_assign_rhs2 (stmt);
6465 /* Reduce number of cases to handle. */
6466 if (is_gimple_min_invariant (op1))
6468 /* Exclude anything that should have been already folded. */
6469 if (rhs_code != EQ_EXPR
6470 && rhs_code != NE_EXPR
6471 && rhs_code != TRUTH_XOR_EXPR)
6474 if (!integer_zerop (op1)
6475 && !integer_onep (op1)
6476 && !integer_all_onesp (op1))
6479 /* Limit the number of cases we have to consider. */
6480 if (rhs_code == EQ_EXPR)
6483 op1 = fold_unary (TRUTH_NOT_EXPR, TREE_TYPE (op1), op1);
6488 /* Punt on A == B as there is no BIT_XNOR_EXPR. */
6489 if (rhs_code == EQ_EXPR)
6492 if (TYPE_PRECISION (TREE_TYPE (op1)) != 1)
6494 vr = get_value_range (op1);
6495 val = compare_range_with_value (GE_EXPR, vr, integer_zero_node, &sop);
6496 if (!val || !integer_onep (val))
6499 val = compare_range_with_value (LE_EXPR, vr, integer_one_node, &sop);
6500 if (!val || !integer_onep (val))
6506 if (sop && issue_strict_overflow_warning (WARN_STRICT_OVERFLOW_MISC))
6508 location_t location;
6510 if (!gimple_has_location (stmt))
6511 location = input_location;
6513 location = gimple_location (stmt);
6515 if (rhs_code == TRUTH_AND_EXPR || rhs_code == TRUTH_OR_EXPR)
6516 warning_at (location, OPT_Wstrict_overflow,
6517 _("assuming signed overflow does not occur when "
6518 "simplifying && or || to & or |"));
6520 warning_at (location, OPT_Wstrict_overflow,
6521 _("assuming signed overflow does not occur when "
6522 "simplifying ==, != or ! to identity or ^"));
6526 !useless_type_conversion_p (TREE_TYPE (gimple_assign_lhs (stmt)),
6529 /* Make sure to not sign-extend -1 as a boolean value. */
6531 && !TYPE_UNSIGNED (TREE_TYPE (op0))
6532 && TYPE_PRECISION (TREE_TYPE (op0)) == 1)
6537 case TRUTH_AND_EXPR:
6538 rhs_code = BIT_AND_EXPR;
6541 rhs_code = BIT_IOR_EXPR;
6543 case TRUTH_XOR_EXPR:
6545 if (integer_zerop (op1))
6547 gimple_assign_set_rhs_with_ops (gsi,
6548 need_conversion ? NOP_EXPR : SSA_NAME,
6550 update_stmt (gsi_stmt (*gsi));
6554 rhs_code = BIT_XOR_EXPR;
6560 if (need_conversion)
6563 gimple_assign_set_rhs_with_ops (gsi, rhs_code, op0, op1);
6564 update_stmt (gsi_stmt (*gsi));
6568 /* Simplify a division or modulo operator to a right shift or
6569 bitwise and if the first operand is unsigned or is greater
6570 than zero and the second operand is an exact power of two. */
6573 simplify_div_or_mod_using_ranges (gimple stmt)
6575 enum tree_code rhs_code = gimple_assign_rhs_code (stmt);
6577 tree op0 = gimple_assign_rhs1 (stmt);
6578 tree op1 = gimple_assign_rhs2 (stmt);
6579 value_range_t *vr = get_value_range (gimple_assign_rhs1 (stmt));
6581 if (TYPE_UNSIGNED (TREE_TYPE (op0)))
6583 val = integer_one_node;
6589 val = compare_range_with_value (GE_EXPR, vr, integer_zero_node, &sop);
6593 && integer_onep (val)
6594 && issue_strict_overflow_warning (WARN_STRICT_OVERFLOW_MISC))
6596 location_t location;
6598 if (!gimple_has_location (stmt))
6599 location = input_location;
6601 location = gimple_location (stmt);
6602 warning (OPT_Wstrict_overflow,
6603 ("%Hassuming signed overflow does not occur when "
6604 "simplifying / or %% to >> or &"),
6609 if (val && integer_onep (val))
6613 if (rhs_code == TRUNC_DIV_EXPR)
6615 t = build_int_cst (NULL_TREE, tree_log2 (op1));
6616 gimple_assign_set_rhs_code (stmt, RSHIFT_EXPR);
6617 gimple_assign_set_rhs1 (stmt, op0);
6618 gimple_assign_set_rhs2 (stmt, t);
6622 t = build_int_cst (TREE_TYPE (op1), 1);
6623 t = int_const_binop (MINUS_EXPR, op1, t, 0);
6624 t = fold_convert (TREE_TYPE (op0), t);
6626 gimple_assign_set_rhs_code (stmt, BIT_AND_EXPR);
6627 gimple_assign_set_rhs1 (stmt, op0);
6628 gimple_assign_set_rhs2 (stmt, t);
6638 /* If the operand to an ABS_EXPR is >= 0, then eliminate the
6639 ABS_EXPR. If the operand is <= 0, then simplify the
6640 ABS_EXPR into a NEGATE_EXPR. */
6643 simplify_abs_using_ranges (gimple stmt)
6646 tree op = gimple_assign_rhs1 (stmt);
6647 tree type = TREE_TYPE (op);
6648 value_range_t *vr = get_value_range (op);
6650 if (TYPE_UNSIGNED (type))
6652 val = integer_zero_node;
6658 val = compare_range_with_value (LE_EXPR, vr, integer_zero_node, &sop);
6662 val = compare_range_with_value (GE_EXPR, vr, integer_zero_node,
6667 if (integer_zerop (val))
6668 val = integer_one_node;
6669 else if (integer_onep (val))
6670 val = integer_zero_node;
6675 && (integer_onep (val) || integer_zerop (val)))
6677 if (sop && issue_strict_overflow_warning (WARN_STRICT_OVERFLOW_MISC))
6679 location_t location;
6681 if (!gimple_has_location (stmt))
6682 location = input_location;
6684 location = gimple_location (stmt);
6685 warning (OPT_Wstrict_overflow,
6686 ("%Hassuming signed overflow does not occur when "
6687 "simplifying abs (X) to X or -X"),
6691 gimple_assign_set_rhs1 (stmt, op);
6692 if (integer_onep (val))
6693 gimple_assign_set_rhs_code (stmt, NEGATE_EXPR);
6695 gimple_assign_set_rhs_code (stmt, SSA_NAME);
6704 /* We are comparing trees OP0 and OP1 using COND_CODE. OP0 has
6705 a known value range VR.
6707 If there is one and only one value which will satisfy the
6708 conditional, then return that value. Else return NULL. */
6711 test_for_singularity (enum tree_code cond_code, tree op0,
6712 tree op1, value_range_t *vr)
6717 /* Extract minimum/maximum values which satisfy the
6718 the conditional as it was written. */
6719 if (cond_code == LE_EXPR || cond_code == LT_EXPR)
6721 /* This should not be negative infinity; there is no overflow
6723 min = TYPE_MIN_VALUE (TREE_TYPE (op0));
6726 if (cond_code == LT_EXPR && !is_overflow_infinity (max))
6728 tree one = build_int_cst (TREE_TYPE (op0), 1);
6729 max = fold_build2 (MINUS_EXPR, TREE_TYPE (op0), max, one);
6731 TREE_NO_WARNING (max) = 1;
6734 else if (cond_code == GE_EXPR || cond_code == GT_EXPR)
6736 /* This should not be positive infinity; there is no overflow
6738 max = TYPE_MAX_VALUE (TREE_TYPE (op0));
6741 if (cond_code == GT_EXPR && !is_overflow_infinity (min))
6743 tree one = build_int_cst (TREE_TYPE (op0), 1);
6744 min = fold_build2 (PLUS_EXPR, TREE_TYPE (op0), min, one);
6746 TREE_NO_WARNING (min) = 1;
6750 /* Now refine the minimum and maximum values using any
6751 value range information we have for op0. */
6754 if (compare_values (vr->min, min) == -1)
6758 if (compare_values (vr->max, max) == 1)
6763 /* If the new min/max values have converged to a single value,
6764 then there is only one value which can satisfy the condition,
6765 return that value. */
6766 if (operand_equal_p (min, max, 0) && is_gimple_min_invariant (min))
6772 /* Simplify a conditional using a relational operator to an equality
6773 test if the range information indicates only one value can satisfy
6774 the original conditional. */
6777 simplify_cond_using_ranges (gimple stmt)
6779 tree op0 = gimple_cond_lhs (stmt);
6780 tree op1 = gimple_cond_rhs (stmt);
6781 enum tree_code cond_code = gimple_cond_code (stmt);
6783 if (cond_code != NE_EXPR
6784 && cond_code != EQ_EXPR
6785 && TREE_CODE (op0) == SSA_NAME
6786 && INTEGRAL_TYPE_P (TREE_TYPE (op0))
6787 && is_gimple_min_invariant (op1))
6789 value_range_t *vr = get_value_range (op0);
6791 /* If we have range information for OP0, then we might be
6792 able to simplify this conditional. */
6793 if (vr->type == VR_RANGE)
6795 tree new_tree = test_for_singularity (cond_code, op0, op1, vr);
6801 fprintf (dump_file, "Simplified relational ");
6802 print_gimple_stmt (dump_file, stmt, 0, 0);
6803 fprintf (dump_file, " into ");
6806 gimple_cond_set_code (stmt, EQ_EXPR);
6807 gimple_cond_set_lhs (stmt, op0);
6808 gimple_cond_set_rhs (stmt, new_tree);
6814 print_gimple_stmt (dump_file, stmt, 0, 0);
6815 fprintf (dump_file, "\n");
6821 /* Try again after inverting the condition. We only deal
6822 with integral types here, so no need to worry about
6823 issues with inverting FP comparisons. */
6824 cond_code = invert_tree_comparison (cond_code, false);
6825 new_tree = test_for_singularity (cond_code, op0, op1, vr);
6831 fprintf (dump_file, "Simplified relational ");
6832 print_gimple_stmt (dump_file, stmt, 0, 0);
6833 fprintf (dump_file, " into ");
6836 gimple_cond_set_code (stmt, NE_EXPR);
6837 gimple_cond_set_lhs (stmt, op0);
6838 gimple_cond_set_rhs (stmt, new_tree);
6844 print_gimple_stmt (dump_file, stmt, 0, 0);
6845 fprintf (dump_file, "\n");
6856 /* Simplify a switch statement using the value range of the switch
6860 simplify_switch_using_ranges (gimple stmt)
6862 tree op = gimple_switch_index (stmt);
6867 size_t i = 0, j = 0, n, n2;
6871 if (TREE_CODE (op) == SSA_NAME)
6873 vr = get_value_range (op);
6875 /* We can only handle integer ranges. */
6876 if (vr->type != VR_RANGE
6877 || symbolic_range_p (vr))
6880 /* Find case label for min/max of the value range. */
6881 take_default = !find_case_label_range (stmt, vr->min, vr->max, &i, &j);
6883 else if (TREE_CODE (op) == INTEGER_CST)
6885 take_default = !find_case_label_index (stmt, 1, op, &i);
6899 n = gimple_switch_num_labels (stmt);
6901 /* Bail out if this is just all edges taken. */
6907 /* Build a new vector of taken case labels. */
6908 vec2 = make_tree_vec (j - i + 1 + (int)take_default);
6911 /* Add the default edge, if necessary. */
6913 TREE_VEC_ELT (vec2, n2++) = gimple_switch_default_label (stmt);
6915 for (; i <= j; ++i, ++n2)
6916 TREE_VEC_ELT (vec2, n2) = gimple_switch_label (stmt, i);
6918 /* Mark needed edges. */
6919 for (i = 0; i < n2; ++i)
6921 e = find_edge (gimple_bb (stmt),
6922 label_to_block (CASE_LABEL (TREE_VEC_ELT (vec2, i))));
6923 e->aux = (void *)-1;
6926 /* Queue not needed edges for later removal. */
6927 FOR_EACH_EDGE (e, ei, gimple_bb (stmt)->succs)
6929 if (e->aux == (void *)-1)
6935 if (dump_file && (dump_flags & TDF_DETAILS))
6937 fprintf (dump_file, "removing unreachable case label\n");
6939 VEC_safe_push (edge, heap, to_remove_edges, e);
6942 /* And queue an update for the stmt. */
6945 VEC_safe_push (switch_update, heap, to_update_switch_stmts, &su);
6949 /* Simplify STMT using ranges if possible. */
6952 simplify_stmt_using_ranges (gimple_stmt_iterator *gsi)
6954 gimple stmt = gsi_stmt (*gsi);
6955 if (is_gimple_assign (stmt))
6957 enum tree_code rhs_code = gimple_assign_rhs_code (stmt);
6963 case TRUTH_NOT_EXPR:
6964 case TRUTH_AND_EXPR:
6966 case TRUTH_XOR_EXPR:
6967 /* Transform EQ_EXPR, NE_EXPR, TRUTH_NOT_EXPR into BIT_XOR_EXPR
6968 or identity if the RHS is zero or one, and the LHS are known
6969 to be boolean values. Transform all TRUTH_*_EXPR into
6970 BIT_*_EXPR if both arguments are known to be boolean values. */
6971 if (INTEGRAL_TYPE_P (TREE_TYPE (gimple_assign_rhs1 (stmt))))
6972 return simplify_truth_ops_using_ranges (gsi, stmt);
6975 /* Transform TRUNC_DIV_EXPR and TRUNC_MOD_EXPR into RSHIFT_EXPR
6976 and BIT_AND_EXPR respectively if the first operand is greater
6977 than zero and the second operand is an exact power of two. */
6978 case TRUNC_DIV_EXPR:
6979 case TRUNC_MOD_EXPR:
6980 if (INTEGRAL_TYPE_P (TREE_TYPE (gimple_assign_rhs1 (stmt)))
6981 && integer_pow2p (gimple_assign_rhs2 (stmt)))
6982 return simplify_div_or_mod_using_ranges (stmt);
6985 /* Transform ABS (X) into X or -X as appropriate. */
6987 if (TREE_CODE (gimple_assign_rhs1 (stmt)) == SSA_NAME
6988 && INTEGRAL_TYPE_P (TREE_TYPE (gimple_assign_rhs1 (stmt))))
6989 return simplify_abs_using_ranges (stmt);
6996 else if (gimple_code (stmt) == GIMPLE_COND)
6997 return simplify_cond_using_ranges (stmt);
6998 else if (gimple_code (stmt) == GIMPLE_SWITCH)
6999 return simplify_switch_using_ranges (stmt);
7004 /* Stack of dest,src equivalency pairs that need to be restored after
7005 each attempt to thread a block's incoming edge to an outgoing edge.
7007 A NULL entry is used to mark the end of pairs which need to be
7009 static VEC(tree,heap) *stack;
7011 /* A trivial wrapper so that we can present the generic jump threading
7012 code with a simple API for simplifying statements. STMT is the
7013 statement we want to simplify, WITHIN_STMT provides the location
7014 for any overflow warnings. */
7017 simplify_stmt_for_jump_threading (gimple stmt, gimple within_stmt)
7019 /* We only use VRP information to simplify conditionals. This is
7020 overly conservative, but it's unclear if doing more would be
7021 worth the compile time cost. */
7022 if (gimple_code (stmt) != GIMPLE_COND)
7025 return vrp_evaluate_conditional (gimple_cond_code (stmt),
7026 gimple_cond_lhs (stmt),
7027 gimple_cond_rhs (stmt), within_stmt);
7030 /* Blocks which have more than one predecessor and more than
7031 one successor present jump threading opportunities, i.e.,
7032 when the block is reached from a specific predecessor, we
7033 may be able to determine which of the outgoing edges will
7034 be traversed. When this optimization applies, we are able
7035 to avoid conditionals at runtime and we may expose secondary
7036 optimization opportunities.
7038 This routine is effectively a driver for the generic jump
7039 threading code. It basically just presents the generic code
7040 with edges that may be suitable for jump threading.
7042 Unlike DOM, we do not iterate VRP if jump threading was successful.
7043 While iterating may expose new opportunities for VRP, it is expected
7044 those opportunities would be very limited and the compile time cost
7045 to expose those opportunities would be significant.
7047 As jump threading opportunities are discovered, they are registered
7048 for later realization. */
7051 identify_jump_threads (void)
7058 /* Ugh. When substituting values earlier in this pass we can
7059 wipe the dominance information. So rebuild the dominator
7060 information as we need it within the jump threading code. */
7061 calculate_dominance_info (CDI_DOMINATORS);
7063 /* We do not allow VRP information to be used for jump threading
7064 across a back edge in the CFG. Otherwise it becomes too
7065 difficult to avoid eliminating loop exit tests. Of course
7066 EDGE_DFS_BACK is not accurate at this time so we have to
7068 mark_dfs_back_edges ();
7070 /* Do not thread across edges we are about to remove. Just marking
7071 them as EDGE_DFS_BACK will do. */
7072 for (i = 0; VEC_iterate (edge, to_remove_edges, i, e); ++i)
7073 e->flags |= EDGE_DFS_BACK;
7075 /* Allocate our unwinder stack to unwind any temporary equivalences
7076 that might be recorded. */
7077 stack = VEC_alloc (tree, heap, 20);
7079 /* To avoid lots of silly node creation, we create a single
7080 conditional and just modify it in-place when attempting to
7082 dummy = gimple_build_cond (EQ_EXPR,
7083 integer_zero_node, integer_zero_node,
7086 /* Walk through all the blocks finding those which present a
7087 potential jump threading opportunity. We could set this up
7088 as a dominator walker and record data during the walk, but
7089 I doubt it's worth the effort for the classes of jump
7090 threading opportunities we are trying to identify at this
7091 point in compilation. */
7096 /* If the generic jump threading code does not find this block
7097 interesting, then there is nothing to do. */
7098 if (! potentially_threadable_block (bb))
7101 /* We only care about blocks ending in a COND_EXPR. While there
7102 may be some value in handling SWITCH_EXPR here, I doubt it's
7103 terribly important. */
7104 last = gsi_stmt (gsi_last_bb (bb));
7105 if (gimple_code (last) != GIMPLE_COND)
7108 /* We're basically looking for any kind of conditional with
7109 integral type arguments. */
7110 if (TREE_CODE (gimple_cond_lhs (last)) == SSA_NAME
7111 && INTEGRAL_TYPE_P (TREE_TYPE (gimple_cond_lhs (last)))
7112 && (TREE_CODE (gimple_cond_rhs (last)) == SSA_NAME
7113 || is_gimple_min_invariant (gimple_cond_rhs (last)))
7114 && INTEGRAL_TYPE_P (TREE_TYPE (gimple_cond_rhs (last))))
7118 /* We've got a block with multiple predecessors and multiple
7119 successors which also ends in a suitable conditional. For
7120 each predecessor, see if we can thread it to a specific
7122 FOR_EACH_EDGE (e, ei, bb->preds)
7124 /* Do not thread across back edges or abnormal edges
7126 if (e->flags & (EDGE_DFS_BACK | EDGE_COMPLEX))
7129 thread_across_edge (dummy, e, true, &stack,
7130 simplify_stmt_for_jump_threading);
7135 /* We do not actually update the CFG or SSA graphs at this point as
7136 ASSERT_EXPRs are still in the IL and cfg cleanup code does not yet
7137 handle ASSERT_EXPRs gracefully. */
7140 /* We identified all the jump threading opportunities earlier, but could
7141 not transform the CFG at that time. This routine transforms the
7142 CFG and arranges for the dominator tree to be rebuilt if necessary.
7144 Note the SSA graph update will occur during the normal TODO
7145 processing by the pass manager. */
7147 finalize_jump_threads (void)
7149 thread_through_all_blocks (false);
7150 VEC_free (tree, heap, stack);
7154 /* Traverse all the blocks folding conditionals with known ranges. */
7160 prop_value_t *single_val_range;
7161 bool do_value_subst_p;
7165 fprintf (dump_file, "\nValue ranges after VRP:\n\n");
7166 dump_all_value_ranges (dump_file);
7167 fprintf (dump_file, "\n");
7170 /* We may have ended with ranges that have exactly one value. Those
7171 values can be substituted as any other copy/const propagated
7172 value using substitute_and_fold. */
7173 single_val_range = XCNEWVEC (prop_value_t, num_ssa_names);
7175 do_value_subst_p = false;
7176 for (i = 0; i < num_ssa_names; i++)
7178 && vr_value[i]->type == VR_RANGE
7179 && vr_value[i]->min == vr_value[i]->max)
7181 single_val_range[i].value = vr_value[i]->min;
7182 do_value_subst_p = true;
7185 if (!do_value_subst_p)
7187 /* We found no single-valued ranges, don't waste time trying to
7188 do single value substitution in substitute_and_fold. */
7189 free (single_val_range);
7190 single_val_range = NULL;
7193 substitute_and_fold (single_val_range, true);
7195 if (warn_array_bounds)
7196 check_all_array_refs ();
7198 /* We must identify jump threading opportunities before we release
7199 the datastructures built by VRP. */
7200 identify_jump_threads ();
7202 /* Free allocated memory. */
7203 for (i = 0; i < num_ssa_names; i++)
7206 BITMAP_FREE (vr_value[i]->equiv);
7210 free (single_val_range);
7212 free (vr_phi_edge_counts);
7214 /* So that we can distinguish between VRP data being available
7215 and not available. */
7217 vr_phi_edge_counts = NULL;
7221 /* Main entry point to VRP (Value Range Propagation). This pass is
7222 loosely based on J. R. C. Patterson, ``Accurate Static Branch
7223 Prediction by Value Range Propagation,'' in SIGPLAN Conference on
7224 Programming Language Design and Implementation, pp. 67-78, 1995.
7225 Also available at http://citeseer.ist.psu.edu/patterson95accurate.html
7227 This is essentially an SSA-CCP pass modified to deal with ranges
7228 instead of constants.
7230 While propagating ranges, we may find that two or more SSA name
7231 have equivalent, though distinct ranges. For instance,
7234 2 p_4 = ASSERT_EXPR <p_3, p_3 != 0>
7236 4 p_5 = ASSERT_EXPR <p_4, p_4 == q_2>;
7240 In the code above, pointer p_5 has range [q_2, q_2], but from the
7241 code we can also determine that p_5 cannot be NULL and, if q_2 had
7242 a non-varying range, p_5's range should also be compatible with it.
7244 These equivalences are created by two expressions: ASSERT_EXPR and
7245 copy operations. Since p_5 is an assertion on p_4, and p_4 was the
7246 result of another assertion, then we can use the fact that p_5 and
7247 p_4 are equivalent when evaluating p_5's range.
7249 Together with value ranges, we also propagate these equivalences
7250 between names so that we can take advantage of information from
7251 multiple ranges when doing final replacement. Note that this
7252 equivalency relation is transitive but not symmetric.
7254 In the example above, p_5 is equivalent to p_4, q_2 and p_3, but we
7255 cannot assert that q_2 is equivalent to p_5 because q_2 may be used
7256 in contexts where that assertion does not hold (e.g., in line 6).
7258 TODO, the main difference between this pass and Patterson's is that
7259 we do not propagate edge probabilities. We only compute whether
7260 edges can be taken or not. That is, instead of having a spectrum
7261 of jump probabilities between 0 and 1, we only deal with 0, 1 and
7262 DON'T KNOW. In the future, it may be worthwhile to propagate
7263 probabilities to aid branch prediction. */
7272 loop_optimizer_init (LOOPS_NORMAL | LOOPS_HAVE_RECORDED_EXITS);
7273 rewrite_into_loop_closed_ssa (NULL, TODO_update_ssa);
7276 insert_range_assertions ();
7278 to_remove_edges = VEC_alloc (edge, heap, 10);
7279 to_update_switch_stmts = VEC_alloc (switch_update, heap, 5);
7280 threadedge_initialize_values ();
7283 ssa_propagate (vrp_visit_stmt, vrp_visit_phi_node);
7286 /* ASSERT_EXPRs must be removed before finalizing jump threads
7287 as finalizing jump threads calls the CFG cleanup code which
7288 does not properly handle ASSERT_EXPRs. */
7289 remove_range_assertions ();
7291 /* If we exposed any new variables, go ahead and put them into
7292 SSA form now, before we handle jump threading. This simplifies
7293 interactions between rewriting of _DECL nodes into SSA form
7294 and rewriting SSA_NAME nodes into SSA form after block
7295 duplication and CFG manipulation. */
7296 update_ssa (TODO_update_ssa);
7298 finalize_jump_threads ();
7300 /* Remove dead edges from SWITCH_EXPR optimization. This leaves the
7301 CFG in a broken state and requires a cfg_cleanup run. */
7302 for (i = 0; VEC_iterate (edge, to_remove_edges, i, e); ++i)
7304 /* Update SWITCH_EXPR case label vector. */
7305 for (i = 0; VEC_iterate (switch_update, to_update_switch_stmts, i, su); ++i)
7308 size_t n = TREE_VEC_LENGTH (su->vec);
7310 gimple_switch_set_num_labels (su->stmt, n);
7311 for (j = 0; j < n; j++)
7312 gimple_switch_set_label (su->stmt, j, TREE_VEC_ELT (su->vec, j));
7313 /* As we may have replaced the default label with a regular one
7314 make sure to make it a real default label again. This ensures
7315 optimal expansion. */
7316 label = gimple_switch_default_label (su->stmt);
7317 CASE_LOW (label) = NULL_TREE;
7318 CASE_HIGH (label) = NULL_TREE;
7321 if (VEC_length (edge, to_remove_edges) > 0)
7322 free_dominance_info (CDI_DOMINATORS);
7324 VEC_free (edge, heap, to_remove_edges);
7325 VEC_free (switch_update, heap, to_update_switch_stmts);
7326 threadedge_finalize_values ();
7329 loop_optimizer_finalize ();
7336 return flag_tree_vrp != 0;
7339 struct gimple_opt_pass pass_vrp =
7344 gate_vrp, /* gate */
7345 execute_vrp, /* execute */
7348 0, /* static_pass_number */
7349 TV_TREE_VRP, /* tv_id */
7350 PROP_ssa | PROP_alias, /* properties_required */
7351 0, /* properties_provided */
7352 0, /* properties_destroyed */
7353 0, /* todo_flags_start */
7358 | TODO_update_ssa /* todo_flags_finish */