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 else if (code == MULT_EXPR
2253 || code == TRUNC_DIV_EXPR
2254 || code == FLOOR_DIV_EXPR
2255 || code == CEIL_DIV_EXPR
2256 || code == EXACT_DIV_EXPR
2257 || code == ROUND_DIV_EXPR
2258 || code == RSHIFT_EXPR)
2264 /* If we have an unsigned MULT_EXPR with two VR_ANTI_RANGEs,
2265 drop to VR_VARYING. It would take more effort to compute a
2266 precise range for such a case. For example, if we have
2267 op0 == 65536 and op1 == 65536 with their ranges both being
2268 ~[0,0] on a 32-bit machine, we would have op0 * op1 == 0, so
2269 we cannot claim that the product is in ~[0,0]. Note that we
2270 are guaranteed to have vr0.type == vr1.type at this
2272 if (code == MULT_EXPR
2273 && vr0.type == VR_ANTI_RANGE
2274 && !TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (op0)))
2276 set_value_range_to_varying (vr);
2280 /* If we have a RSHIFT_EXPR with any shift values outside [0..prec-1],
2281 then drop to VR_VARYING. Outside of this range we get undefined
2282 behavior from the shift operation. We cannot even trust
2283 SHIFT_COUNT_TRUNCATED at this stage, because that applies to rtl
2284 shifts, and the operation at the tree level may be widened. */
2285 if (code == RSHIFT_EXPR)
2287 if (vr1.type == VR_ANTI_RANGE
2288 || !vrp_expr_computes_nonnegative (op1, &sop)
2290 (build_int_cst (TREE_TYPE (vr1.max),
2291 TYPE_PRECISION (expr_type) - 1),
2294 set_value_range_to_varying (vr);
2299 else if ((code == TRUNC_DIV_EXPR
2300 || code == FLOOR_DIV_EXPR
2301 || code == CEIL_DIV_EXPR
2302 || code == EXACT_DIV_EXPR
2303 || code == ROUND_DIV_EXPR)
2304 && (vr0.type != VR_RANGE || symbolic_range_p (&vr0)))
2306 /* For division, if op1 has VR_RANGE but op0 does not, something
2307 can be deduced just from that range. Say [min, max] / [4, max]
2308 gives [min / 4, max / 4] range. */
2309 if (vr1.type == VR_RANGE
2310 && !symbolic_range_p (&vr1)
2311 && !range_includes_zero_p (&vr1))
2313 vr0.type = type = VR_RANGE;
2314 vr0.min = vrp_val_min (TREE_TYPE (op0));
2315 vr0.max = vrp_val_max (TREE_TYPE (op1));
2319 set_value_range_to_varying (vr);
2324 /* For divisions, if op0 is VR_RANGE, we can deduce a range
2325 even if op1 is VR_VARYING, VR_ANTI_RANGE, symbolic or can
2327 if ((code == TRUNC_DIV_EXPR
2328 || code == FLOOR_DIV_EXPR
2329 || code == CEIL_DIV_EXPR
2330 || code == EXACT_DIV_EXPR
2331 || code == ROUND_DIV_EXPR)
2332 && vr0.type == VR_RANGE
2333 && (vr1.type != VR_RANGE
2334 || symbolic_range_p (&vr1)
2335 || range_includes_zero_p (&vr1)))
2337 tree zero = build_int_cst (TREE_TYPE (vr0.min), 0);
2343 if (vrp_expr_computes_nonnegative (op1, &sop) && !sop)
2345 /* For unsigned division or when divisor is known
2346 to be non-negative, the range has to cover
2347 all numbers from 0 to max for positive max
2348 and all numbers from min to 0 for negative min. */
2349 cmp = compare_values (vr0.max, zero);
2352 else if (cmp == 0 || cmp == 1)
2356 cmp = compare_values (vr0.min, zero);
2359 else if (cmp == 0 || cmp == -1)
2366 /* Otherwise the range is -max .. max or min .. -min
2367 depending on which bound is bigger in absolute value,
2368 as the division can change the sign. */
2369 abs_extent_range (vr, vr0.min, vr0.max);
2372 if (type == VR_VARYING)
2374 set_value_range_to_varying (vr);
2379 /* Multiplications and divisions are a bit tricky to handle,
2380 depending on the mix of signs we have in the two ranges, we
2381 need to operate on different values to get the minimum and
2382 maximum values for the new range. One approach is to figure
2383 out all the variations of range combinations and do the
2386 However, this involves several calls to compare_values and it
2387 is pretty convoluted. It's simpler to do the 4 operations
2388 (MIN0 OP MIN1, MIN0 OP MAX1, MAX0 OP MIN1 and MAX0 OP MAX0 OP
2389 MAX1) and then figure the smallest and largest values to form
2393 gcc_assert ((vr0.type == VR_RANGE
2394 || (code == MULT_EXPR && vr0.type == VR_ANTI_RANGE))
2395 && vr0.type == vr1.type);
2397 /* Compute the 4 cross operations. */
2399 val[0] = vrp_int_const_binop (code, vr0.min, vr1.min);
2400 if (val[0] == NULL_TREE)
2403 if (vr1.max == vr1.min)
2407 val[1] = vrp_int_const_binop (code, vr0.min, vr1.max);
2408 if (val[1] == NULL_TREE)
2412 if (vr0.max == vr0.min)
2416 val[2] = vrp_int_const_binop (code, vr0.max, vr1.min);
2417 if (val[2] == NULL_TREE)
2421 if (vr0.min == vr0.max || vr1.min == vr1.max)
2425 val[3] = vrp_int_const_binop (code, vr0.max, vr1.max);
2426 if (val[3] == NULL_TREE)
2432 set_value_range_to_varying (vr);
2436 /* Set MIN to the minimum of VAL[i] and MAX to the maximum
2440 for (i = 1; i < 4; i++)
2442 if (!is_gimple_min_invariant (min)
2443 || (TREE_OVERFLOW (min) && !is_overflow_infinity (min))
2444 || !is_gimple_min_invariant (max)
2445 || (TREE_OVERFLOW (max) && !is_overflow_infinity (max)))
2450 if (!is_gimple_min_invariant (val[i])
2451 || (TREE_OVERFLOW (val[i])
2452 && !is_overflow_infinity (val[i])))
2454 /* If we found an overflowed value, set MIN and MAX
2455 to it so that we set the resulting range to
2461 if (compare_values (val[i], min) == -1)
2464 if (compare_values (val[i], max) == 1)
2470 else if (code == MINUS_EXPR)
2472 /* If we have a MINUS_EXPR with two VR_ANTI_RANGEs, drop to
2473 VR_VARYING. It would take more effort to compute a precise
2474 range for such a case. For example, if we have op0 == 1 and
2475 op1 == 1 with their ranges both being ~[0,0], we would have
2476 op0 - op1 == 0, so we cannot claim that the difference is in
2477 ~[0,0]. Note that we are guaranteed to have
2478 vr0.type == vr1.type at this point. */
2479 if (vr0.type == VR_ANTI_RANGE)
2481 set_value_range_to_varying (vr);
2485 /* For MINUS_EXPR, apply the operation to the opposite ends of
2487 min = vrp_int_const_binop (code, vr0.min, vr1.max);
2488 max = vrp_int_const_binop (code, vr0.max, vr1.min);
2490 else if (code == BIT_AND_EXPR)
2492 if (vr0.type == VR_RANGE
2493 && vr0.min == vr0.max
2494 && TREE_CODE (vr0.max) == INTEGER_CST
2495 && !TREE_OVERFLOW (vr0.max)
2496 && tree_int_cst_sgn (vr0.max) >= 0)
2498 min = build_int_cst (expr_type, 0);
2501 else if (vr1.type == VR_RANGE
2502 && vr1.min == vr1.max
2503 && TREE_CODE (vr1.max) == INTEGER_CST
2504 && !TREE_OVERFLOW (vr1.max)
2505 && tree_int_cst_sgn (vr1.max) >= 0)
2508 min = build_int_cst (expr_type, 0);
2513 set_value_range_to_varying (vr);
2517 else if (code == BIT_IOR_EXPR)
2519 if (vr0.type == VR_RANGE
2520 && vr1.type == VR_RANGE
2521 && TREE_CODE (vr0.min) == INTEGER_CST
2522 && TREE_CODE (vr1.min) == INTEGER_CST
2523 && TREE_CODE (vr0.max) == INTEGER_CST
2524 && TREE_CODE (vr1.max) == INTEGER_CST
2525 && tree_int_cst_sgn (vr0.min) >= 0
2526 && tree_int_cst_sgn (vr1.min) >= 0)
2528 double_int vr0_max = tree_to_double_int (vr0.max);
2529 double_int vr1_max = tree_to_double_int (vr1.max);
2532 /* Set all bits to the right of the most significant one to 1.
2533 For example, [0, 4] | [4, 4] = [4, 7]. */
2534 ior_max.low = vr0_max.low | vr1_max.low;
2535 ior_max.high = vr0_max.high | vr1_max.high;
2536 if (ior_max.high != 0)
2538 ior_max.low = ~(unsigned HOST_WIDE_INT)0u;
2539 ior_max.high |= ((HOST_WIDE_INT) 1
2540 << floor_log2 (ior_max.high)) - 1;
2542 else if (ior_max.low != 0)
2543 ior_max.low |= ((unsigned HOST_WIDE_INT) 1u
2544 << floor_log2 (ior_max.low)) - 1;
2546 /* Both of these endpoints are conservative. */
2547 min = vrp_int_const_binop (MAX_EXPR, vr0.min, vr1.min);
2548 max = double_int_to_tree (expr_type, ior_max);
2552 set_value_range_to_varying (vr);
2559 /* If either MIN or MAX overflowed, then set the resulting range to
2560 VARYING. But we do accept an overflow infinity
2562 if (min == NULL_TREE
2563 || !is_gimple_min_invariant (min)
2564 || (TREE_OVERFLOW (min) && !is_overflow_infinity (min))
2566 || !is_gimple_min_invariant (max)
2567 || (TREE_OVERFLOW (max) && !is_overflow_infinity (max)))
2569 set_value_range_to_varying (vr);
2575 2) [-INF, +-INF(OVF)]
2576 3) [+-INF(OVF), +INF]
2577 4) [+-INF(OVF), +-INF(OVF)]
2578 We learn nothing when we have INF and INF(OVF) on both sides.
2579 Note that we do accept [-INF, -INF] and [+INF, +INF] without
2581 if ((vrp_val_is_min (min) || is_overflow_infinity (min))
2582 && (vrp_val_is_max (max) || is_overflow_infinity (max)))
2584 set_value_range_to_varying (vr);
2588 cmp = compare_values (min, max);
2589 if (cmp == -2 || cmp == 1)
2591 /* If the new range has its limits swapped around (MIN > MAX),
2592 then the operation caused one of them to wrap around, mark
2593 the new range VARYING. */
2594 set_value_range_to_varying (vr);
2597 set_value_range (vr, type, min, max, NULL);
2601 /* Extract range information from a unary expression EXPR based on
2602 the range of its operand and the expression code. */
2605 extract_range_from_unary_expr (value_range_t *vr, enum tree_code code,
2606 tree type, tree op0)
2610 value_range_t vr0 = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
2612 /* Refuse to operate on certain unary expressions for which we
2613 cannot easily determine a resulting range. */
2614 if (code == FIX_TRUNC_EXPR
2615 || code == FLOAT_EXPR
2616 || code == BIT_NOT_EXPR
2617 || code == CONJ_EXPR)
2619 /* We can still do constant propagation here. */
2620 if ((op0 = op_with_constant_singleton_value_range (op0)) != NULL_TREE)
2622 tree tem = fold_unary (code, type, op0);
2624 && is_gimple_min_invariant (tem)
2625 && !is_overflow_infinity (tem))
2627 set_value_range (vr, VR_RANGE, tem, tem, NULL);
2631 set_value_range_to_varying (vr);
2635 /* Get value ranges for the operand. For constant operands, create
2636 a new value range with the operand to simplify processing. */
2637 if (TREE_CODE (op0) == SSA_NAME)
2638 vr0 = *(get_value_range (op0));
2639 else if (is_gimple_min_invariant (op0))
2640 set_value_range_to_value (&vr0, op0, NULL);
2642 set_value_range_to_varying (&vr0);
2644 /* If VR0 is UNDEFINED, so is the result. */
2645 if (vr0.type == VR_UNDEFINED)
2647 set_value_range_to_undefined (vr);
2651 /* Refuse to operate on symbolic ranges, or if neither operand is
2652 a pointer or integral type. */
2653 if ((!INTEGRAL_TYPE_P (TREE_TYPE (op0))
2654 && !POINTER_TYPE_P (TREE_TYPE (op0)))
2655 || (vr0.type != VR_VARYING
2656 && symbolic_range_p (&vr0)))
2658 set_value_range_to_varying (vr);
2662 /* If the expression involves pointers, we are only interested in
2663 determining if it evaluates to NULL [0, 0] or non-NULL (~[0, 0]). */
2664 if (POINTER_TYPE_P (type) || POINTER_TYPE_P (TREE_TYPE (op0)))
2669 if (range_is_nonnull (&vr0)
2670 || (tree_unary_nonzero_warnv_p (code, type, op0, &sop)
2672 set_value_range_to_nonnull (vr, type);
2673 else if (range_is_null (&vr0))
2674 set_value_range_to_null (vr, type);
2676 set_value_range_to_varying (vr);
2681 /* Handle unary expressions on integer ranges. */
2682 if (CONVERT_EXPR_CODE_P (code)
2683 && INTEGRAL_TYPE_P (type)
2684 && INTEGRAL_TYPE_P (TREE_TYPE (op0)))
2686 tree inner_type = TREE_TYPE (op0);
2687 tree outer_type = type;
2689 /* Always use base-types here. This is important for the
2690 correct signedness. */
2691 if (TREE_TYPE (inner_type))
2692 inner_type = TREE_TYPE (inner_type);
2693 if (TREE_TYPE (outer_type))
2694 outer_type = TREE_TYPE (outer_type);
2696 /* If VR0 is varying and we increase the type precision, assume
2697 a full range for the following transformation. */
2698 if (vr0.type == VR_VARYING
2699 && TYPE_PRECISION (inner_type) < TYPE_PRECISION (outer_type))
2701 vr0.type = VR_RANGE;
2702 vr0.min = TYPE_MIN_VALUE (inner_type);
2703 vr0.max = TYPE_MAX_VALUE (inner_type);
2706 /* If VR0 is a constant range or anti-range and the conversion is
2707 not truncating we can convert the min and max values and
2708 canonicalize the resulting range. Otherwise we can do the
2709 conversion if the size of the range is less than what the
2710 precision of the target type can represent and the range is
2711 not an anti-range. */
2712 if ((vr0.type == VR_RANGE
2713 || vr0.type == VR_ANTI_RANGE)
2714 && TREE_CODE (vr0.min) == INTEGER_CST
2715 && TREE_CODE (vr0.max) == INTEGER_CST
2716 && !is_overflow_infinity (vr0.min)
2717 && !is_overflow_infinity (vr0.max)
2718 && (TYPE_PRECISION (outer_type) >= TYPE_PRECISION (inner_type)
2719 || (vr0.type == VR_RANGE
2720 && integer_zerop (int_const_binop (RSHIFT_EXPR,
2721 int_const_binop (MINUS_EXPR, vr0.max, vr0.min, 0),
2722 size_int (TYPE_PRECISION (outer_type)), 0)))))
2724 tree new_min, new_max;
2725 new_min = force_fit_type_double (outer_type,
2726 TREE_INT_CST_LOW (vr0.min),
2727 TREE_INT_CST_HIGH (vr0.min), 0, 0);
2728 new_max = force_fit_type_double (outer_type,
2729 TREE_INT_CST_LOW (vr0.max),
2730 TREE_INT_CST_HIGH (vr0.max), 0, 0);
2731 set_and_canonicalize_value_range (vr, vr0.type,
2732 new_min, new_max, NULL);
2736 set_value_range_to_varying (vr);
2740 /* Conversion of a VR_VARYING value to a wider type can result
2741 in a usable range. So wait until after we've handled conversions
2742 before dropping the result to VR_VARYING if we had a source
2743 operand that is VR_VARYING. */
2744 if (vr0.type == VR_VARYING)
2746 set_value_range_to_varying (vr);
2750 /* Apply the operation to each end of the range and see what we end
2752 if (code == NEGATE_EXPR
2753 && !TYPE_UNSIGNED (type))
2755 /* NEGATE_EXPR flips the range around. We need to treat
2756 TYPE_MIN_VALUE specially. */
2757 if (is_positive_overflow_infinity (vr0.max))
2758 min = negative_overflow_infinity (type);
2759 else if (is_negative_overflow_infinity (vr0.max))
2760 min = positive_overflow_infinity (type);
2761 else if (!vrp_val_is_min (vr0.max))
2762 min = fold_unary_to_constant (code, type, vr0.max);
2763 else if (needs_overflow_infinity (type))
2765 if (supports_overflow_infinity (type)
2766 && !is_overflow_infinity (vr0.min)
2767 && !vrp_val_is_min (vr0.min))
2768 min = positive_overflow_infinity (type);
2771 set_value_range_to_varying (vr);
2776 min = TYPE_MIN_VALUE (type);
2778 if (is_positive_overflow_infinity (vr0.min))
2779 max = negative_overflow_infinity (type);
2780 else if (is_negative_overflow_infinity (vr0.min))
2781 max = positive_overflow_infinity (type);
2782 else if (!vrp_val_is_min (vr0.min))
2783 max = fold_unary_to_constant (code, type, vr0.min);
2784 else if (needs_overflow_infinity (type))
2786 if (supports_overflow_infinity (type))
2787 max = positive_overflow_infinity (type);
2790 set_value_range_to_varying (vr);
2795 max = TYPE_MIN_VALUE (type);
2797 else if (code == NEGATE_EXPR
2798 && TYPE_UNSIGNED (type))
2800 if (!range_includes_zero_p (&vr0))
2802 max = fold_unary_to_constant (code, type, vr0.min);
2803 min = fold_unary_to_constant (code, type, vr0.max);
2807 if (range_is_null (&vr0))
2808 set_value_range_to_null (vr, type);
2810 set_value_range_to_varying (vr);
2814 else if (code == ABS_EXPR
2815 && !TYPE_UNSIGNED (type))
2817 /* -TYPE_MIN_VALUE = TYPE_MIN_VALUE with flag_wrapv so we can't get a
2819 if (!TYPE_OVERFLOW_UNDEFINED (type)
2820 && ((vr0.type == VR_RANGE
2821 && vrp_val_is_min (vr0.min))
2822 || (vr0.type == VR_ANTI_RANGE
2823 && !vrp_val_is_min (vr0.min)
2824 && !range_includes_zero_p (&vr0))))
2826 set_value_range_to_varying (vr);
2830 /* ABS_EXPR may flip the range around, if the original range
2831 included negative values. */
2832 if (is_overflow_infinity (vr0.min))
2833 min = positive_overflow_infinity (type);
2834 else if (!vrp_val_is_min (vr0.min))
2835 min = fold_unary_to_constant (code, type, vr0.min);
2836 else if (!needs_overflow_infinity (type))
2837 min = TYPE_MAX_VALUE (type);
2838 else if (supports_overflow_infinity (type))
2839 min = positive_overflow_infinity (type);
2842 set_value_range_to_varying (vr);
2846 if (is_overflow_infinity (vr0.max))
2847 max = positive_overflow_infinity (type);
2848 else if (!vrp_val_is_min (vr0.max))
2849 max = fold_unary_to_constant (code, type, vr0.max);
2850 else if (!needs_overflow_infinity (type))
2851 max = TYPE_MAX_VALUE (type);
2852 else if (supports_overflow_infinity (type)
2853 /* We shouldn't generate [+INF, +INF] as set_value_range
2854 doesn't like this and ICEs. */
2855 && !is_positive_overflow_infinity (min))
2856 max = positive_overflow_infinity (type);
2859 set_value_range_to_varying (vr);
2863 cmp = compare_values (min, max);
2865 /* If a VR_ANTI_RANGEs contains zero, then we have
2866 ~[-INF, min(MIN, MAX)]. */
2867 if (vr0.type == VR_ANTI_RANGE)
2869 if (range_includes_zero_p (&vr0))
2871 /* Take the lower of the two values. */
2875 /* Create ~[-INF, min (abs(MIN), abs(MAX))]
2876 or ~[-INF + 1, min (abs(MIN), abs(MAX))] when
2877 flag_wrapv is set and the original anti-range doesn't include
2878 TYPE_MIN_VALUE, remember -TYPE_MIN_VALUE = TYPE_MIN_VALUE. */
2879 if (TYPE_OVERFLOW_WRAPS (type))
2881 tree type_min_value = TYPE_MIN_VALUE (type);
2883 min = (vr0.min != type_min_value
2884 ? int_const_binop (PLUS_EXPR, type_min_value,
2885 integer_one_node, 0)
2890 if (overflow_infinity_range_p (&vr0))
2891 min = negative_overflow_infinity (type);
2893 min = TYPE_MIN_VALUE (type);
2898 /* All else has failed, so create the range [0, INF], even for
2899 flag_wrapv since TYPE_MIN_VALUE is in the original
2901 vr0.type = VR_RANGE;
2902 min = build_int_cst (type, 0);
2903 if (needs_overflow_infinity (type))
2905 if (supports_overflow_infinity (type))
2906 max = positive_overflow_infinity (type);
2909 set_value_range_to_varying (vr);
2914 max = TYPE_MAX_VALUE (type);
2918 /* If the range contains zero then we know that the minimum value in the
2919 range will be zero. */
2920 else if (range_includes_zero_p (&vr0))
2924 min = build_int_cst (type, 0);
2928 /* If the range was reversed, swap MIN and MAX. */
2939 /* Otherwise, operate on each end of the range. */
2940 min = fold_unary_to_constant (code, type, vr0.min);
2941 max = fold_unary_to_constant (code, type, vr0.max);
2943 if (needs_overflow_infinity (type))
2945 gcc_assert (code != NEGATE_EXPR && code != ABS_EXPR);
2947 /* If both sides have overflowed, we don't know
2949 if ((is_overflow_infinity (vr0.min)
2950 || TREE_OVERFLOW (min))
2951 && (is_overflow_infinity (vr0.max)
2952 || TREE_OVERFLOW (max)))
2954 set_value_range_to_varying (vr);
2958 if (is_overflow_infinity (vr0.min))
2960 else if (TREE_OVERFLOW (min))
2962 if (supports_overflow_infinity (type))
2963 min = (tree_int_cst_sgn (min) >= 0
2964 ? positive_overflow_infinity (TREE_TYPE (min))
2965 : negative_overflow_infinity (TREE_TYPE (min)));
2968 set_value_range_to_varying (vr);
2973 if (is_overflow_infinity (vr0.max))
2975 else if (TREE_OVERFLOW (max))
2977 if (supports_overflow_infinity (type))
2978 max = (tree_int_cst_sgn (max) >= 0
2979 ? positive_overflow_infinity (TREE_TYPE (max))
2980 : negative_overflow_infinity (TREE_TYPE (max)));
2983 set_value_range_to_varying (vr);
2990 cmp = compare_values (min, max);
2991 if (cmp == -2 || cmp == 1)
2993 /* If the new range has its limits swapped around (MIN > MAX),
2994 then the operation caused one of them to wrap around, mark
2995 the new range VARYING. */
2996 set_value_range_to_varying (vr);
2999 set_value_range (vr, vr0.type, min, max, NULL);
3003 /* Extract range information from a conditional expression EXPR based on
3004 the ranges of each of its operands and the expression code. */
3007 extract_range_from_cond_expr (value_range_t *vr, tree expr)
3010 value_range_t vr0 = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
3011 value_range_t vr1 = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
3013 /* Get value ranges for each operand. For constant operands, create
3014 a new value range with the operand to simplify processing. */
3015 op0 = COND_EXPR_THEN (expr);
3016 if (TREE_CODE (op0) == SSA_NAME)
3017 vr0 = *(get_value_range (op0));
3018 else if (is_gimple_min_invariant (op0))
3019 set_value_range_to_value (&vr0, op0, NULL);
3021 set_value_range_to_varying (&vr0);
3023 op1 = COND_EXPR_ELSE (expr);
3024 if (TREE_CODE (op1) == SSA_NAME)
3025 vr1 = *(get_value_range (op1));
3026 else if (is_gimple_min_invariant (op1))
3027 set_value_range_to_value (&vr1, op1, NULL);
3029 set_value_range_to_varying (&vr1);
3031 /* The resulting value range is the union of the operand ranges */
3032 vrp_meet (&vr0, &vr1);
3033 copy_value_range (vr, &vr0);
3037 /* Extract range information from a comparison expression EXPR based
3038 on the range of its operand and the expression code. */
3041 extract_range_from_comparison (value_range_t *vr, enum tree_code code,
3042 tree type, tree op0, tree op1)
3047 val = vrp_evaluate_conditional_warnv_with_ops (code, op0, op1, false, &sop,
3050 /* A disadvantage of using a special infinity as an overflow
3051 representation is that we lose the ability to record overflow
3052 when we don't have an infinity. So we have to ignore a result
3053 which relies on overflow. */
3055 if (val && !is_overflow_infinity (val) && !sop)
3057 /* Since this expression was found on the RHS of an assignment,
3058 its type may be different from _Bool. Convert VAL to EXPR's
3060 val = fold_convert (type, val);
3061 if (is_gimple_min_invariant (val))
3062 set_value_range_to_value (vr, val, vr->equiv);
3064 set_value_range (vr, VR_RANGE, val, val, vr->equiv);
3067 /* The result of a comparison is always true or false. */
3068 set_value_range_to_truthvalue (vr, type);
3071 /* Try to derive a nonnegative or nonzero range out of STMT relying
3072 primarily on generic routines in fold in conjunction with range data.
3073 Store the result in *VR */
3076 extract_range_basic (value_range_t *vr, gimple stmt)
3079 tree type = gimple_expr_type (stmt);
3081 if (INTEGRAL_TYPE_P (type)
3082 && gimple_stmt_nonnegative_warnv_p (stmt, &sop))
3083 set_value_range_to_nonnegative (vr, type,
3084 sop || stmt_overflow_infinity (stmt));
3085 else if (vrp_stmt_computes_nonzero (stmt, &sop)
3087 set_value_range_to_nonnull (vr, type);
3089 set_value_range_to_varying (vr);
3093 /* Try to compute a useful range out of assignment STMT and store it
3097 extract_range_from_assignment (value_range_t *vr, gimple stmt)
3099 enum tree_code code = gimple_assign_rhs_code (stmt);
3101 if (code == ASSERT_EXPR)
3102 extract_range_from_assert (vr, gimple_assign_rhs1 (stmt));
3103 else if (code == SSA_NAME)
3104 extract_range_from_ssa_name (vr, gimple_assign_rhs1 (stmt));
3105 else if (TREE_CODE_CLASS (code) == tcc_binary
3106 || code == TRUTH_AND_EXPR
3107 || code == TRUTH_OR_EXPR
3108 || code == TRUTH_XOR_EXPR)
3109 extract_range_from_binary_expr (vr, gimple_assign_rhs_code (stmt),
3110 gimple_expr_type (stmt),
3111 gimple_assign_rhs1 (stmt),
3112 gimple_assign_rhs2 (stmt));
3113 else if (TREE_CODE_CLASS (code) == tcc_unary)
3114 extract_range_from_unary_expr (vr, gimple_assign_rhs_code (stmt),
3115 gimple_expr_type (stmt),
3116 gimple_assign_rhs1 (stmt));
3117 else if (code == COND_EXPR)
3118 extract_range_from_cond_expr (vr, gimple_assign_rhs1 (stmt));
3119 else if (TREE_CODE_CLASS (code) == tcc_comparison)
3120 extract_range_from_comparison (vr, gimple_assign_rhs_code (stmt),
3121 gimple_expr_type (stmt),
3122 gimple_assign_rhs1 (stmt),
3123 gimple_assign_rhs2 (stmt));
3124 else if (get_gimple_rhs_class (code) == GIMPLE_SINGLE_RHS
3125 && is_gimple_min_invariant (gimple_assign_rhs1 (stmt)))
3126 set_value_range_to_value (vr, gimple_assign_rhs1 (stmt), NULL);
3128 set_value_range_to_varying (vr);
3130 if (vr->type == VR_VARYING)
3131 extract_range_basic (vr, stmt);
3134 /* Given a range VR, a LOOP and a variable VAR, determine whether it
3135 would be profitable to adjust VR using scalar evolution information
3136 for VAR. If so, update VR with the new limits. */
3139 adjust_range_with_scev (value_range_t *vr, struct loop *loop,
3140 gimple stmt, tree var)
3142 tree init, step, chrec, tmin, tmax, min, max, type;
3143 enum ev_direction dir;
3145 /* TODO. Don't adjust anti-ranges. An anti-range may provide
3146 better opportunities than a regular range, but I'm not sure. */
3147 if (vr->type == VR_ANTI_RANGE)
3150 chrec = instantiate_parameters (loop, analyze_scalar_evolution (loop, var));
3152 /* Like in PR19590, scev can return a constant function. */
3153 if (is_gimple_min_invariant (chrec))
3155 set_value_range_to_value (vr, chrec, vr->equiv);
3159 if (TREE_CODE (chrec) != POLYNOMIAL_CHREC)
3162 init = initial_condition_in_loop_num (chrec, loop->num);
3163 step = evolution_part_in_loop_num (chrec, loop->num);
3165 /* If STEP is symbolic, we can't know whether INIT will be the
3166 minimum or maximum value in the range. Also, unless INIT is
3167 a simple expression, compare_values and possibly other functions
3168 in tree-vrp won't be able to handle it. */
3169 if (step == NULL_TREE
3170 || !is_gimple_min_invariant (step)
3171 || !valid_value_p (init))
3174 dir = scev_direction (chrec);
3175 if (/* Do not adjust ranges if we do not know whether the iv increases
3176 or decreases, ... */
3177 dir == EV_DIR_UNKNOWN
3178 /* ... or if it may wrap. */
3179 || scev_probably_wraps_p (init, step, stmt, get_chrec_loop (chrec),
3183 /* We use TYPE_MIN_VALUE and TYPE_MAX_VALUE here instead of
3184 negative_overflow_infinity and positive_overflow_infinity,
3185 because we have concluded that the loop probably does not
3188 type = TREE_TYPE (var);
3189 if (POINTER_TYPE_P (type) || !TYPE_MIN_VALUE (type))
3190 tmin = lower_bound_in_type (type, type);
3192 tmin = TYPE_MIN_VALUE (type);
3193 if (POINTER_TYPE_P (type) || !TYPE_MAX_VALUE (type))
3194 tmax = upper_bound_in_type (type, type);
3196 tmax = TYPE_MAX_VALUE (type);
3198 if (vr->type == VR_VARYING || vr->type == VR_UNDEFINED)
3203 /* For VARYING or UNDEFINED ranges, just about anything we get
3204 from scalar evolutions should be better. */
3206 if (dir == EV_DIR_DECREASES)
3211 /* If we would create an invalid range, then just assume we
3212 know absolutely nothing. This may be over-conservative,
3213 but it's clearly safe, and should happen only in unreachable
3214 parts of code, or for invalid programs. */
3215 if (compare_values (min, max) == 1)
3218 set_value_range (vr, VR_RANGE, min, max, vr->equiv);
3220 else if (vr->type == VR_RANGE)
3225 if (dir == EV_DIR_DECREASES)
3227 /* INIT is the maximum value. If INIT is lower than VR->MAX
3228 but no smaller than VR->MIN, set VR->MAX to INIT. */
3229 if (compare_values (init, max) == -1)
3233 /* If we just created an invalid range with the minimum
3234 greater than the maximum, we fail conservatively.
3235 This should happen only in unreachable
3236 parts of code, or for invalid programs. */
3237 if (compare_values (min, max) == 1)
3241 /* According to the loop information, the variable does not
3242 overflow. If we think it does, probably because of an
3243 overflow due to arithmetic on a different INF value,
3245 if (is_negative_overflow_infinity (min))
3250 /* If INIT is bigger than VR->MIN, set VR->MIN to INIT. */
3251 if (compare_values (init, min) == 1)
3255 /* Again, avoid creating invalid range by failing. */
3256 if (compare_values (min, max) == 1)
3260 if (is_positive_overflow_infinity (max))
3264 set_value_range (vr, VR_RANGE, min, max, vr->equiv);
3268 /* Return true if VAR may overflow at STMT. This checks any available
3269 loop information to see if we can determine that VAR does not
3273 vrp_var_may_overflow (tree var, gimple stmt)
3276 tree chrec, init, step;
3278 if (current_loops == NULL)
3281 l = loop_containing_stmt (stmt);
3285 chrec = instantiate_parameters (l, analyze_scalar_evolution (l, var));
3286 if (TREE_CODE (chrec) != POLYNOMIAL_CHREC)
3289 init = initial_condition_in_loop_num (chrec, l->num);
3290 step = evolution_part_in_loop_num (chrec, l->num);
3292 if (step == NULL_TREE
3293 || !is_gimple_min_invariant (step)
3294 || !valid_value_p (init))
3297 /* If we get here, we know something useful about VAR based on the
3298 loop information. If it wraps, it may overflow. */
3300 if (scev_probably_wraps_p (init, step, stmt, get_chrec_loop (chrec),
3304 if (dump_file && (dump_flags & TDF_DETAILS) != 0)
3306 print_generic_expr (dump_file, var, 0);
3307 fprintf (dump_file, ": loop information indicates does not overflow\n");
3314 /* Given two numeric value ranges VR0, VR1 and a comparison code COMP:
3316 - Return BOOLEAN_TRUE_NODE if VR0 COMP VR1 always returns true for
3317 all the values in the ranges.
3319 - Return BOOLEAN_FALSE_NODE if the comparison always returns false.
3321 - Return NULL_TREE if it is not always possible to determine the
3322 value of the comparison.
3324 Also set *STRICT_OVERFLOW_P to indicate whether a range with an
3325 overflow infinity was used in the test. */
3329 compare_ranges (enum tree_code comp, value_range_t *vr0, value_range_t *vr1,
3330 bool *strict_overflow_p)
3332 /* VARYING or UNDEFINED ranges cannot be compared. */
3333 if (vr0->type == VR_VARYING
3334 || vr0->type == VR_UNDEFINED
3335 || vr1->type == VR_VARYING
3336 || vr1->type == VR_UNDEFINED)
3339 /* Anti-ranges need to be handled separately. */
3340 if (vr0->type == VR_ANTI_RANGE || vr1->type == VR_ANTI_RANGE)
3342 /* If both are anti-ranges, then we cannot compute any
3344 if (vr0->type == VR_ANTI_RANGE && vr1->type == VR_ANTI_RANGE)
3347 /* These comparisons are never statically computable. */
3354 /* Equality can be computed only between a range and an
3355 anti-range. ~[VAL1, VAL2] == [VAL1, VAL2] is always false. */
3356 if (vr0->type == VR_RANGE)
3358 /* To simplify processing, make VR0 the anti-range. */
3359 value_range_t *tmp = vr0;
3364 gcc_assert (comp == NE_EXPR || comp == EQ_EXPR);
3366 if (compare_values_warnv (vr0->min, vr1->min, strict_overflow_p) == 0
3367 && compare_values_warnv (vr0->max, vr1->max, strict_overflow_p) == 0)
3368 return (comp == NE_EXPR) ? boolean_true_node : boolean_false_node;
3373 if (!usable_range_p (vr0, strict_overflow_p)
3374 || !usable_range_p (vr1, strict_overflow_p))
3377 /* Simplify processing. If COMP is GT_EXPR or GE_EXPR, switch the
3378 operands around and change the comparison code. */
3379 if (comp == GT_EXPR || comp == GE_EXPR)
3382 comp = (comp == GT_EXPR) ? LT_EXPR : LE_EXPR;
3388 if (comp == EQ_EXPR)
3390 /* Equality may only be computed if both ranges represent
3391 exactly one value. */
3392 if (compare_values_warnv (vr0->min, vr0->max, strict_overflow_p) == 0
3393 && compare_values_warnv (vr1->min, vr1->max, strict_overflow_p) == 0)
3395 int cmp_min = compare_values_warnv (vr0->min, vr1->min,
3397 int cmp_max = compare_values_warnv (vr0->max, vr1->max,
3399 if (cmp_min == 0 && cmp_max == 0)
3400 return boolean_true_node;
3401 else if (cmp_min != -2 && cmp_max != -2)
3402 return boolean_false_node;
3404 /* If [V0_MIN, V1_MAX] < [V1_MIN, V1_MAX] then V0 != V1. */
3405 else if (compare_values_warnv (vr0->min, vr1->max,
3406 strict_overflow_p) == 1
3407 || compare_values_warnv (vr1->min, vr0->max,
3408 strict_overflow_p) == 1)
3409 return boolean_false_node;
3413 else if (comp == NE_EXPR)
3417 /* If VR0 is completely to the left or completely to the right
3418 of VR1, they are always different. Notice that we need to
3419 make sure that both comparisons yield similar results to
3420 avoid comparing values that cannot be compared at
3422 cmp1 = compare_values_warnv (vr0->max, vr1->min, strict_overflow_p);
3423 cmp2 = compare_values_warnv (vr0->min, vr1->max, strict_overflow_p);
3424 if ((cmp1 == -1 && cmp2 == -1) || (cmp1 == 1 && cmp2 == 1))
3425 return boolean_true_node;
3427 /* If VR0 and VR1 represent a single value and are identical,
3429 else if (compare_values_warnv (vr0->min, vr0->max,
3430 strict_overflow_p) == 0
3431 && compare_values_warnv (vr1->min, vr1->max,
3432 strict_overflow_p) == 0
3433 && compare_values_warnv (vr0->min, vr1->min,
3434 strict_overflow_p) == 0
3435 && compare_values_warnv (vr0->max, vr1->max,
3436 strict_overflow_p) == 0)
3437 return boolean_false_node;
3439 /* Otherwise, they may or may not be different. */
3443 else if (comp == LT_EXPR || comp == LE_EXPR)
3447 /* If VR0 is to the left of VR1, return true. */
3448 tst = compare_values_warnv (vr0->max, vr1->min, strict_overflow_p);
3449 if ((comp == LT_EXPR && tst == -1)
3450 || (comp == LE_EXPR && (tst == -1 || tst == 0)))
3452 if (overflow_infinity_range_p (vr0)
3453 || overflow_infinity_range_p (vr1))
3454 *strict_overflow_p = true;
3455 return boolean_true_node;
3458 /* If VR0 is to the right of VR1, return false. */
3459 tst = compare_values_warnv (vr0->min, vr1->max, strict_overflow_p);
3460 if ((comp == LT_EXPR && (tst == 0 || tst == 1))
3461 || (comp == LE_EXPR && tst == 1))
3463 if (overflow_infinity_range_p (vr0)
3464 || overflow_infinity_range_p (vr1))
3465 *strict_overflow_p = true;
3466 return boolean_false_node;
3469 /* Otherwise, we don't know. */
3477 /* Given a value range VR, a value VAL and a comparison code COMP, return
3478 BOOLEAN_TRUE_NODE if VR COMP VAL always returns true for all the
3479 values in VR. Return BOOLEAN_FALSE_NODE if the comparison
3480 always returns false. Return NULL_TREE if it is not always
3481 possible to determine the value of the comparison. Also set
3482 *STRICT_OVERFLOW_P to indicate whether a range with an overflow
3483 infinity was used in the test. */
3486 compare_range_with_value (enum tree_code comp, value_range_t *vr, tree val,
3487 bool *strict_overflow_p)
3489 if (vr->type == VR_VARYING || vr->type == VR_UNDEFINED)
3492 /* Anti-ranges need to be handled separately. */
3493 if (vr->type == VR_ANTI_RANGE)
3495 /* For anti-ranges, the only predicates that we can compute at
3496 compile time are equality and inequality. */
3503 /* ~[VAL_1, VAL_2] OP VAL is known if VAL_1 <= VAL <= VAL_2. */
3504 if (value_inside_range (val, vr) == 1)
3505 return (comp == NE_EXPR) ? boolean_true_node : boolean_false_node;
3510 if (!usable_range_p (vr, strict_overflow_p))
3513 if (comp == EQ_EXPR)
3515 /* EQ_EXPR may only be computed if VR represents exactly
3517 if (compare_values_warnv (vr->min, vr->max, strict_overflow_p) == 0)
3519 int cmp = compare_values_warnv (vr->min, val, strict_overflow_p);
3521 return boolean_true_node;
3522 else if (cmp == -1 || cmp == 1 || cmp == 2)
3523 return boolean_false_node;
3525 else if (compare_values_warnv (val, vr->min, strict_overflow_p) == -1
3526 || compare_values_warnv (vr->max, val, strict_overflow_p) == -1)
3527 return boolean_false_node;
3531 else if (comp == NE_EXPR)
3533 /* If VAL is not inside VR, then they are always different. */
3534 if (compare_values_warnv (vr->max, val, strict_overflow_p) == -1
3535 || compare_values_warnv (vr->min, val, strict_overflow_p) == 1)
3536 return boolean_true_node;
3538 /* If VR represents exactly one value equal to VAL, then return
3540 if (compare_values_warnv (vr->min, vr->max, strict_overflow_p) == 0
3541 && compare_values_warnv (vr->min, val, strict_overflow_p) == 0)
3542 return boolean_false_node;
3544 /* Otherwise, they may or may not be different. */
3547 else if (comp == LT_EXPR || comp == LE_EXPR)
3551 /* If VR is to the left of VAL, return true. */
3552 tst = compare_values_warnv (vr->max, val, strict_overflow_p);
3553 if ((comp == LT_EXPR && tst == -1)
3554 || (comp == LE_EXPR && (tst == -1 || tst == 0)))
3556 if (overflow_infinity_range_p (vr))
3557 *strict_overflow_p = true;
3558 return boolean_true_node;
3561 /* If VR is to the right of VAL, return false. */
3562 tst = compare_values_warnv (vr->min, val, strict_overflow_p);
3563 if ((comp == LT_EXPR && (tst == 0 || tst == 1))
3564 || (comp == LE_EXPR && tst == 1))
3566 if (overflow_infinity_range_p (vr))
3567 *strict_overflow_p = true;
3568 return boolean_false_node;
3571 /* Otherwise, we don't know. */
3574 else if (comp == GT_EXPR || comp == GE_EXPR)
3578 /* If VR is to the right of VAL, return true. */
3579 tst = compare_values_warnv (vr->min, val, strict_overflow_p);
3580 if ((comp == GT_EXPR && tst == 1)
3581 || (comp == GE_EXPR && (tst == 0 || tst == 1)))
3583 if (overflow_infinity_range_p (vr))
3584 *strict_overflow_p = true;
3585 return boolean_true_node;
3588 /* If VR is to the left of VAL, return false. */
3589 tst = compare_values_warnv (vr->max, val, strict_overflow_p);
3590 if ((comp == GT_EXPR && (tst == -1 || tst == 0))
3591 || (comp == GE_EXPR && tst == -1))
3593 if (overflow_infinity_range_p (vr))
3594 *strict_overflow_p = true;
3595 return boolean_false_node;
3598 /* Otherwise, we don't know. */
3606 /* Debugging dumps. */
3608 void dump_value_range (FILE *, value_range_t *);
3609 void debug_value_range (value_range_t *);
3610 void dump_all_value_ranges (FILE *);
3611 void debug_all_value_ranges (void);
3612 void dump_vr_equiv (FILE *, bitmap);
3613 void debug_vr_equiv (bitmap);
3616 /* Dump value range VR to FILE. */
3619 dump_value_range (FILE *file, value_range_t *vr)
3622 fprintf (file, "[]");
3623 else if (vr->type == VR_UNDEFINED)
3624 fprintf (file, "UNDEFINED");
3625 else if (vr->type == VR_RANGE || vr->type == VR_ANTI_RANGE)
3627 tree type = TREE_TYPE (vr->min);
3629 fprintf (file, "%s[", (vr->type == VR_ANTI_RANGE) ? "~" : "");
3631 if (is_negative_overflow_infinity (vr->min))
3632 fprintf (file, "-INF(OVF)");
3633 else if (INTEGRAL_TYPE_P (type)
3634 && !TYPE_UNSIGNED (type)
3635 && vrp_val_is_min (vr->min))
3636 fprintf (file, "-INF");
3638 print_generic_expr (file, vr->min, 0);
3640 fprintf (file, ", ");
3642 if (is_positive_overflow_infinity (vr->max))
3643 fprintf (file, "+INF(OVF)");
3644 else if (INTEGRAL_TYPE_P (type)
3645 && vrp_val_is_max (vr->max))
3646 fprintf (file, "+INF");
3648 print_generic_expr (file, vr->max, 0);
3650 fprintf (file, "]");
3657 fprintf (file, " EQUIVALENCES: { ");
3659 EXECUTE_IF_SET_IN_BITMAP (vr->equiv, 0, i, bi)
3661 print_generic_expr (file, ssa_name (i), 0);
3662 fprintf (file, " ");
3666 fprintf (file, "} (%u elements)", c);
3669 else if (vr->type == VR_VARYING)
3670 fprintf (file, "VARYING");
3672 fprintf (file, "INVALID RANGE");
3676 /* Dump value range VR to stderr. */
3679 debug_value_range (value_range_t *vr)
3681 dump_value_range (stderr, vr);
3682 fprintf (stderr, "\n");
3686 /* Dump value ranges of all SSA_NAMEs to FILE. */
3689 dump_all_value_ranges (FILE *file)
3693 for (i = 0; i < num_ssa_names; i++)
3697 print_generic_expr (file, ssa_name (i), 0);
3698 fprintf (file, ": ");
3699 dump_value_range (file, vr_value[i]);
3700 fprintf (file, "\n");
3704 fprintf (file, "\n");
3708 /* Dump all value ranges to stderr. */
3711 debug_all_value_ranges (void)
3713 dump_all_value_ranges (stderr);
3717 /* Given a COND_EXPR COND of the form 'V OP W', and an SSA name V,
3718 create a new SSA name N and return the assertion assignment
3719 'V = ASSERT_EXPR <V, V OP W>'. */
3722 build_assert_expr_for (tree cond, tree v)
3727 gcc_assert (TREE_CODE (v) == SSA_NAME);
3728 n = duplicate_ssa_name (v, NULL);
3730 if (COMPARISON_CLASS_P (cond))
3732 tree a = build2 (ASSERT_EXPR, TREE_TYPE (v), v, cond);
3733 assertion = gimple_build_assign (n, a);
3735 else if (TREE_CODE (cond) == TRUTH_NOT_EXPR)
3737 /* Given !V, build the assignment N = false. */
3738 tree op0 = TREE_OPERAND (cond, 0);
3739 gcc_assert (op0 == v);
3740 assertion = gimple_build_assign (n, boolean_false_node);
3742 else if (TREE_CODE (cond) == SSA_NAME)
3744 /* Given V, build the assignment N = true. */
3745 gcc_assert (v == cond);
3746 assertion = gimple_build_assign (n, boolean_true_node);
3751 SSA_NAME_DEF_STMT (n) = assertion;
3753 /* The new ASSERT_EXPR, creates a new SSA name that replaces the
3754 operand of the ASSERT_EXPR. Register the new name and the old one
3755 in the replacement table so that we can fix the SSA web after
3756 adding all the ASSERT_EXPRs. */
3757 register_new_name_mapping (n, v);
3763 /* Return false if EXPR is a predicate expression involving floating
3767 fp_predicate (gimple stmt)
3769 GIMPLE_CHECK (stmt, GIMPLE_COND);
3771 return FLOAT_TYPE_P (TREE_TYPE (gimple_cond_lhs (stmt)));
3775 /* If the range of values taken by OP can be inferred after STMT executes,
3776 return the comparison code (COMP_CODE_P) and value (VAL_P) that
3777 describes the inferred range. Return true if a range could be
3781 infer_value_range (gimple stmt, tree op, enum tree_code *comp_code_p, tree *val_p)
3784 *comp_code_p = ERROR_MARK;
3786 /* Do not attempt to infer anything in names that flow through
3788 if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (op))
3791 /* Similarly, don't infer anything from statements that may throw
3793 if (stmt_could_throw_p (stmt))
3796 /* If STMT is the last statement of a basic block with no
3797 successors, there is no point inferring anything about any of its
3798 operands. We would not be able to find a proper insertion point
3799 for the assertion, anyway. */
3800 if (stmt_ends_bb_p (stmt) && EDGE_COUNT (gimple_bb (stmt)->succs) == 0)
3803 /* We can only assume that a pointer dereference will yield
3804 non-NULL if -fdelete-null-pointer-checks is enabled. */
3805 if (flag_delete_null_pointer_checks
3806 && POINTER_TYPE_P (TREE_TYPE (op))
3807 && gimple_code (stmt) != GIMPLE_ASM)
3809 unsigned num_uses, num_loads, num_stores;
3811 count_uses_and_derefs (op, stmt, &num_uses, &num_loads, &num_stores);
3812 if (num_loads + num_stores > 0)
3814 *val_p = build_int_cst (TREE_TYPE (op), 0);
3815 *comp_code_p = NE_EXPR;
3824 void dump_asserts_for (FILE *, tree);
3825 void debug_asserts_for (tree);
3826 void dump_all_asserts (FILE *);
3827 void debug_all_asserts (void);
3829 /* Dump all the registered assertions for NAME to FILE. */
3832 dump_asserts_for (FILE *file, tree name)
3836 fprintf (file, "Assertions to be inserted for ");
3837 print_generic_expr (file, name, 0);
3838 fprintf (file, "\n");
3840 loc = asserts_for[SSA_NAME_VERSION (name)];
3843 fprintf (file, "\t");
3844 print_gimple_stmt (file, gsi_stmt (loc->si), 0, 0);
3845 fprintf (file, "\n\tBB #%d", loc->bb->index);
3848 fprintf (file, "\n\tEDGE %d->%d", loc->e->src->index,
3849 loc->e->dest->index);
3850 dump_edge_info (file, loc->e, 0);
3852 fprintf (file, "\n\tPREDICATE: ");
3853 print_generic_expr (file, name, 0);
3854 fprintf (file, " %s ", tree_code_name[(int)loc->comp_code]);
3855 print_generic_expr (file, loc->val, 0);
3856 fprintf (file, "\n\n");
3860 fprintf (file, "\n");
3864 /* Dump all the registered assertions for NAME to stderr. */
3867 debug_asserts_for (tree name)
3869 dump_asserts_for (stderr, name);
3873 /* Dump all the registered assertions for all the names to FILE. */
3876 dump_all_asserts (FILE *file)
3881 fprintf (file, "\nASSERT_EXPRs to be inserted\n\n");
3882 EXECUTE_IF_SET_IN_BITMAP (need_assert_for, 0, i, bi)
3883 dump_asserts_for (file, ssa_name (i));
3884 fprintf (file, "\n");
3888 /* Dump all the registered assertions for all the names to stderr. */
3891 debug_all_asserts (void)
3893 dump_all_asserts (stderr);
3897 /* If NAME doesn't have an ASSERT_EXPR registered for asserting
3898 'EXPR COMP_CODE VAL' at a location that dominates block BB or
3899 E->DEST, then register this location as a possible insertion point
3900 for ASSERT_EXPR <NAME, EXPR COMP_CODE VAL>.
3902 BB, E and SI provide the exact insertion point for the new
3903 ASSERT_EXPR. If BB is NULL, then the ASSERT_EXPR is to be inserted
3904 on edge E. Otherwise, if E is NULL, the ASSERT_EXPR is inserted on
3905 BB. If SI points to a COND_EXPR or a SWITCH_EXPR statement, then E
3906 must not be NULL. */
3909 register_new_assert_for (tree name, tree expr,
3910 enum tree_code comp_code,
3914 gimple_stmt_iterator si)
3916 assert_locus_t n, loc, last_loc;
3918 basic_block dest_bb;
3920 #if defined ENABLE_CHECKING
3921 gcc_assert (bb == NULL || e == NULL);
3924 gcc_assert (gimple_code (gsi_stmt (si)) != GIMPLE_COND
3925 && gimple_code (gsi_stmt (si)) != GIMPLE_SWITCH);
3928 /* Never build an assert comparing against an integer constant with
3929 TREE_OVERFLOW set. This confuses our undefined overflow warning
3931 if (TREE_CODE (val) == INTEGER_CST
3932 && TREE_OVERFLOW (val))
3933 val = build_int_cst_wide (TREE_TYPE (val),
3934 TREE_INT_CST_LOW (val), TREE_INT_CST_HIGH (val));
3936 /* The new assertion A will be inserted at BB or E. We need to
3937 determine if the new location is dominated by a previously
3938 registered location for A. If we are doing an edge insertion,
3939 assume that A will be inserted at E->DEST. Note that this is not
3942 If E is a critical edge, it will be split. But even if E is
3943 split, the new block will dominate the same set of blocks that
3946 The reverse, however, is not true, blocks dominated by E->DEST
3947 will not be dominated by the new block created to split E. So,
3948 if the insertion location is on a critical edge, we will not use
3949 the new location to move another assertion previously registered
3950 at a block dominated by E->DEST. */
3951 dest_bb = (bb) ? bb : e->dest;
3953 /* If NAME already has an ASSERT_EXPR registered for COMP_CODE and
3954 VAL at a block dominating DEST_BB, then we don't need to insert a new
3955 one. Similarly, if the same assertion already exists at a block
3956 dominated by DEST_BB and the new location is not on a critical
3957 edge, then update the existing location for the assertion (i.e.,
3958 move the assertion up in the dominance tree).
3960 Note, this is implemented as a simple linked list because there
3961 should not be more than a handful of assertions registered per
3962 name. If this becomes a performance problem, a table hashed by
3963 COMP_CODE and VAL could be implemented. */
3964 loc = asserts_for[SSA_NAME_VERSION (name)];
3969 if (loc->comp_code == comp_code
3971 || operand_equal_p (loc->val, val, 0))
3972 && (loc->expr == expr
3973 || operand_equal_p (loc->expr, expr, 0)))
3975 /* If the assertion NAME COMP_CODE VAL has already been
3976 registered at a basic block that dominates DEST_BB, then
3977 we don't need to insert the same assertion again. Note
3978 that we don't check strict dominance here to avoid
3979 replicating the same assertion inside the same basic
3980 block more than once (e.g., when a pointer is
3981 dereferenced several times inside a block).
3983 An exception to this rule are edge insertions. If the
3984 new assertion is to be inserted on edge E, then it will
3985 dominate all the other insertions that we may want to
3986 insert in DEST_BB. So, if we are doing an edge
3987 insertion, don't do this dominance check. */
3989 && dominated_by_p (CDI_DOMINATORS, dest_bb, loc->bb))
3992 /* Otherwise, if E is not a critical edge and DEST_BB
3993 dominates the existing location for the assertion, move
3994 the assertion up in the dominance tree by updating its
3995 location information. */
3996 if ((e == NULL || !EDGE_CRITICAL_P (e))
3997 && dominated_by_p (CDI_DOMINATORS, loc->bb, dest_bb))
4006 /* Update the last node of the list and move to the next one. */
4011 /* If we didn't find an assertion already registered for
4012 NAME COMP_CODE VAL, add a new one at the end of the list of
4013 assertions associated with NAME. */
4014 n = XNEW (struct assert_locus_d);
4018 n->comp_code = comp_code;
4026 asserts_for[SSA_NAME_VERSION (name)] = n;
4028 bitmap_set_bit (need_assert_for, SSA_NAME_VERSION (name));
4031 /* (COND_OP0 COND_CODE COND_OP1) is a predicate which uses NAME.
4032 Extract a suitable test code and value and store them into *CODE_P and
4033 *VAL_P so the predicate is normalized to NAME *CODE_P *VAL_P.
4035 If no extraction was possible, return FALSE, otherwise return TRUE.
4037 If INVERT is true, then we invert the result stored into *CODE_P. */
4040 extract_code_and_val_from_cond_with_ops (tree name, enum tree_code cond_code,
4041 tree cond_op0, tree cond_op1,
4042 bool invert, enum tree_code *code_p,
4045 enum tree_code comp_code;
4048 /* Otherwise, we have a comparison of the form NAME COMP VAL
4049 or VAL COMP NAME. */
4050 if (name == cond_op1)
4052 /* If the predicate is of the form VAL COMP NAME, flip
4053 COMP around because we need to register NAME as the
4054 first operand in the predicate. */
4055 comp_code = swap_tree_comparison (cond_code);
4060 /* The comparison is of the form NAME COMP VAL, so the
4061 comparison code remains unchanged. */
4062 comp_code = cond_code;
4066 /* Invert the comparison code as necessary. */
4068 comp_code = invert_tree_comparison (comp_code, 0);
4070 /* VRP does not handle float types. */
4071 if (SCALAR_FLOAT_TYPE_P (TREE_TYPE (val)))
4074 /* Do not register always-false predicates.
4075 FIXME: this works around a limitation in fold() when dealing with
4076 enumerations. Given 'enum { N1, N2 } x;', fold will not
4077 fold 'if (x > N2)' to 'if (0)'. */
4078 if ((comp_code == GT_EXPR || comp_code == LT_EXPR)
4079 && INTEGRAL_TYPE_P (TREE_TYPE (val)))
4081 tree min = TYPE_MIN_VALUE (TREE_TYPE (val));
4082 tree max = TYPE_MAX_VALUE (TREE_TYPE (val));
4084 if (comp_code == GT_EXPR
4086 || compare_values (val, max) == 0))
4089 if (comp_code == LT_EXPR
4091 || compare_values (val, min) == 0))
4094 *code_p = comp_code;
4099 /* Try to register an edge assertion for SSA name NAME on edge E for
4100 the condition COND contributing to the conditional jump pointed to by BSI.
4101 Invert the condition COND if INVERT is true.
4102 Return true if an assertion for NAME could be registered. */
4105 register_edge_assert_for_2 (tree name, edge e, gimple_stmt_iterator bsi,
4106 enum tree_code cond_code,
4107 tree cond_op0, tree cond_op1, bool invert)
4110 enum tree_code comp_code;
4111 bool retval = false;
4113 if (!extract_code_and_val_from_cond_with_ops (name, cond_code,
4116 invert, &comp_code, &val))
4119 /* Only register an ASSERT_EXPR if NAME was found in the sub-graph
4120 reachable from E. */
4121 if (live_on_edge (e, name)
4122 && !has_single_use (name))
4124 register_new_assert_for (name, name, comp_code, val, NULL, e, bsi);
4128 /* In the case of NAME <= CST and NAME being defined as
4129 NAME = (unsigned) NAME2 + CST2 we can assert NAME2 >= -CST2
4130 and NAME2 <= CST - CST2. We can do the same for NAME > CST.
4131 This catches range and anti-range tests. */
4132 if ((comp_code == LE_EXPR
4133 || comp_code == GT_EXPR)
4134 && TREE_CODE (val) == INTEGER_CST
4135 && TYPE_UNSIGNED (TREE_TYPE (val)))
4137 gimple def_stmt = SSA_NAME_DEF_STMT (name);
4138 tree cst2 = NULL_TREE, name2 = NULL_TREE, name3 = NULL_TREE;
4140 /* Extract CST2 from the (optional) addition. */
4141 if (is_gimple_assign (def_stmt)
4142 && gimple_assign_rhs_code (def_stmt) == PLUS_EXPR)
4144 name2 = gimple_assign_rhs1 (def_stmt);
4145 cst2 = gimple_assign_rhs2 (def_stmt);
4146 if (TREE_CODE (name2) == SSA_NAME
4147 && TREE_CODE (cst2) == INTEGER_CST)
4148 def_stmt = SSA_NAME_DEF_STMT (name2);
4151 /* Extract NAME2 from the (optional) sign-changing cast. */
4152 if (gimple_assign_cast_p (def_stmt))
4154 if (CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (def_stmt))
4155 && ! TYPE_UNSIGNED (TREE_TYPE (gimple_assign_rhs1 (def_stmt)))
4156 && (TYPE_PRECISION (gimple_expr_type (def_stmt))
4157 == TYPE_PRECISION (TREE_TYPE (gimple_assign_rhs1 (def_stmt)))))
4158 name3 = gimple_assign_rhs1 (def_stmt);
4161 /* If name3 is used later, create an ASSERT_EXPR for it. */
4162 if (name3 != NULL_TREE
4163 && TREE_CODE (name3) == SSA_NAME
4164 && (cst2 == NULL_TREE
4165 || TREE_CODE (cst2) == INTEGER_CST)
4166 && INTEGRAL_TYPE_P (TREE_TYPE (name3))
4167 && live_on_edge (e, name3)
4168 && !has_single_use (name3))
4172 /* Build an expression for the range test. */
4173 tmp = build1 (NOP_EXPR, TREE_TYPE (name), name3);
4174 if (cst2 != NULL_TREE)
4175 tmp = build2 (PLUS_EXPR, TREE_TYPE (name), tmp, cst2);
4179 fprintf (dump_file, "Adding assert for ");
4180 print_generic_expr (dump_file, name3, 0);
4181 fprintf (dump_file, " from ");
4182 print_generic_expr (dump_file, tmp, 0);
4183 fprintf (dump_file, "\n");
4186 register_new_assert_for (name3, tmp, comp_code, val, NULL, e, bsi);
4191 /* If name2 is used later, create an ASSERT_EXPR for it. */
4192 if (name2 != NULL_TREE
4193 && TREE_CODE (name2) == SSA_NAME
4194 && TREE_CODE (cst2) == INTEGER_CST
4195 && INTEGRAL_TYPE_P (TREE_TYPE (name2))
4196 && live_on_edge (e, name2)
4197 && !has_single_use (name2))
4201 /* Build an expression for the range test. */
4203 if (TREE_TYPE (name) != TREE_TYPE (name2))
4204 tmp = build1 (NOP_EXPR, TREE_TYPE (name), tmp);
4205 if (cst2 != NULL_TREE)
4206 tmp = build2 (PLUS_EXPR, TREE_TYPE (name), tmp, cst2);
4210 fprintf (dump_file, "Adding assert for ");
4211 print_generic_expr (dump_file, name2, 0);
4212 fprintf (dump_file, " from ");
4213 print_generic_expr (dump_file, tmp, 0);
4214 fprintf (dump_file, "\n");
4217 register_new_assert_for (name2, tmp, comp_code, val, NULL, e, bsi);
4226 /* OP is an operand of a truth value expression which is known to have
4227 a particular value. Register any asserts for OP and for any
4228 operands in OP's defining statement.
4230 If CODE is EQ_EXPR, then we want to register OP is zero (false),
4231 if CODE is NE_EXPR, then we want to register OP is nonzero (true). */
4234 register_edge_assert_for_1 (tree op, enum tree_code code,
4235 edge e, gimple_stmt_iterator bsi)
4237 bool retval = false;
4240 enum tree_code rhs_code;
4242 /* We only care about SSA_NAMEs. */
4243 if (TREE_CODE (op) != SSA_NAME)
4246 /* We know that OP will have a zero or nonzero value. If OP is used
4247 more than once go ahead and register an assert for OP.
4249 The FOUND_IN_SUBGRAPH support is not helpful in this situation as
4250 it will always be set for OP (because OP is used in a COND_EXPR in
4252 if (!has_single_use (op))
4254 val = build_int_cst (TREE_TYPE (op), 0);
4255 register_new_assert_for (op, op, code, val, NULL, e, bsi);
4259 /* Now look at how OP is set. If it's set from a comparison,
4260 a truth operation or some bit operations, then we may be able
4261 to register information about the operands of that assignment. */
4262 op_def = SSA_NAME_DEF_STMT (op);
4263 if (gimple_code (op_def) != GIMPLE_ASSIGN)
4266 rhs_code = gimple_assign_rhs_code (op_def);
4268 if (TREE_CODE_CLASS (rhs_code) == tcc_comparison)
4270 bool invert = (code == EQ_EXPR ? true : false);
4271 tree op0 = gimple_assign_rhs1 (op_def);
4272 tree op1 = gimple_assign_rhs2 (op_def);
4274 if (TREE_CODE (op0) == SSA_NAME)
4275 retval |= register_edge_assert_for_2 (op0, e, bsi, rhs_code, op0, op1,
4277 if (TREE_CODE (op1) == SSA_NAME)
4278 retval |= register_edge_assert_for_2 (op1, e, bsi, rhs_code, op0, op1,
4281 else if ((code == NE_EXPR
4282 && (gimple_assign_rhs_code (op_def) == TRUTH_AND_EXPR
4283 || gimple_assign_rhs_code (op_def) == BIT_AND_EXPR))
4285 && (gimple_assign_rhs_code (op_def) == TRUTH_OR_EXPR
4286 || gimple_assign_rhs_code (op_def) == BIT_IOR_EXPR)))
4288 /* Recurse on each operand. */
4289 retval |= register_edge_assert_for_1 (gimple_assign_rhs1 (op_def),
4291 retval |= register_edge_assert_for_1 (gimple_assign_rhs2 (op_def),
4294 else if (gimple_assign_rhs_code (op_def) == TRUTH_NOT_EXPR)
4296 /* Recurse, flipping CODE. */
4297 code = invert_tree_comparison (code, false);
4298 retval |= register_edge_assert_for_1 (gimple_assign_rhs1 (op_def),
4301 else if (gimple_assign_rhs_code (op_def) == SSA_NAME)
4303 /* Recurse through the copy. */
4304 retval |= register_edge_assert_for_1 (gimple_assign_rhs1 (op_def),
4307 else if (CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (op_def)))
4309 /* Recurse through the type conversion. */
4310 retval |= register_edge_assert_for_1 (gimple_assign_rhs1 (op_def),
4317 /* Try to register an edge assertion for SSA name NAME on edge E for
4318 the condition COND contributing to the conditional jump pointed to by SI.
4319 Return true if an assertion for NAME could be registered. */
4322 register_edge_assert_for (tree name, edge e, gimple_stmt_iterator si,
4323 enum tree_code cond_code, tree cond_op0,
4327 enum tree_code comp_code;
4328 bool retval = false;
4329 bool is_else_edge = (e->flags & EDGE_FALSE_VALUE) != 0;
4331 /* Do not attempt to infer anything in names that flow through
4333 if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (name))
4336 if (!extract_code_and_val_from_cond_with_ops (name, cond_code,
4342 /* Register ASSERT_EXPRs for name. */
4343 retval |= register_edge_assert_for_2 (name, e, si, cond_code, cond_op0,
4344 cond_op1, is_else_edge);
4347 /* If COND is effectively an equality test of an SSA_NAME against
4348 the value zero or one, then we may be able to assert values
4349 for SSA_NAMEs which flow into COND. */
4351 /* In the case of NAME == 1 or NAME != 0, for TRUTH_AND_EXPR defining
4352 statement of NAME we can assert both operands of the TRUTH_AND_EXPR
4353 have nonzero value. */
4354 if (((comp_code == EQ_EXPR && integer_onep (val))
4355 || (comp_code == NE_EXPR && integer_zerop (val))))
4357 gimple def_stmt = SSA_NAME_DEF_STMT (name);
4359 if (is_gimple_assign (def_stmt)
4360 && (gimple_assign_rhs_code (def_stmt) == TRUTH_AND_EXPR
4361 || gimple_assign_rhs_code (def_stmt) == BIT_AND_EXPR))
4363 tree op0 = gimple_assign_rhs1 (def_stmt);
4364 tree op1 = gimple_assign_rhs2 (def_stmt);
4365 retval |= register_edge_assert_for_1 (op0, NE_EXPR, e, si);
4366 retval |= register_edge_assert_for_1 (op1, NE_EXPR, e, si);
4370 /* In the case of NAME == 0 or NAME != 1, for TRUTH_OR_EXPR defining
4371 statement of NAME we can assert both operands of the TRUTH_OR_EXPR
4373 if (((comp_code == EQ_EXPR && integer_zerop (val))
4374 || (comp_code == NE_EXPR && integer_onep (val))))
4376 gimple def_stmt = SSA_NAME_DEF_STMT (name);
4378 if (is_gimple_assign (def_stmt)
4379 && (gimple_assign_rhs_code (def_stmt) == TRUTH_OR_EXPR
4380 /* For BIT_IOR_EXPR only if NAME == 0 both operands have
4381 necessarily zero value. */
4382 || (comp_code == EQ_EXPR
4383 && (gimple_assign_rhs_code (def_stmt) == BIT_IOR_EXPR))))
4385 tree op0 = gimple_assign_rhs1 (def_stmt);
4386 tree op1 = gimple_assign_rhs2 (def_stmt);
4387 retval |= register_edge_assert_for_1 (op0, EQ_EXPR, e, si);
4388 retval |= register_edge_assert_for_1 (op1, EQ_EXPR, e, si);
4396 /* Determine whether the outgoing edges of BB should receive an
4397 ASSERT_EXPR for each of the operands of BB's LAST statement.
4398 The last statement of BB must be a COND_EXPR.
4400 If any of the sub-graphs rooted at BB have an interesting use of
4401 the predicate operands, an assert location node is added to the
4402 list of assertions for the corresponding operands. */
4405 find_conditional_asserts (basic_block bb, gimple last)
4408 gimple_stmt_iterator bsi;
4414 need_assert = false;
4415 bsi = gsi_for_stmt (last);
4417 /* Look for uses of the operands in each of the sub-graphs
4418 rooted at BB. We need to check each of the outgoing edges
4419 separately, so that we know what kind of ASSERT_EXPR to
4421 FOR_EACH_EDGE (e, ei, bb->succs)
4426 /* Register the necessary assertions for each operand in the
4427 conditional predicate. */
4428 FOR_EACH_SSA_TREE_OPERAND (op, last, iter, SSA_OP_USE)
4430 need_assert |= register_edge_assert_for (op, e, bsi,
4431 gimple_cond_code (last),
4432 gimple_cond_lhs (last),
4433 gimple_cond_rhs (last));
4440 /* Compare two case labels sorting first by the destination label uid
4441 and then by the case value. */
4444 compare_case_labels (const void *p1, const void *p2)
4446 const_tree const case1 = *(const_tree const*)p1;
4447 const_tree const case2 = *(const_tree const*)p2;
4448 unsigned int uid1 = DECL_UID (CASE_LABEL (case1));
4449 unsigned int uid2 = DECL_UID (CASE_LABEL (case2));
4453 else if (uid1 == uid2)
4455 /* Make sure the default label is first in a group. */
4456 if (!CASE_LOW (case1))
4458 else if (!CASE_LOW (case2))
4461 return tree_int_cst_compare (CASE_LOW (case1), CASE_LOW (case2));
4467 /* Determine whether the outgoing edges of BB should receive an
4468 ASSERT_EXPR for each of the operands of BB's LAST statement.
4469 The last statement of BB must be a SWITCH_EXPR.
4471 If any of the sub-graphs rooted at BB have an interesting use of
4472 the predicate operands, an assert location node is added to the
4473 list of assertions for the corresponding operands. */
4476 find_switch_asserts (basic_block bb, gimple last)
4479 gimple_stmt_iterator bsi;
4483 size_t n = gimple_switch_num_labels(last);
4484 #if GCC_VERSION >= 4000
4487 /* Work around GCC 3.4 bug (PR 37086). */
4488 volatile unsigned int idx;
4491 need_assert = false;
4492 bsi = gsi_for_stmt (last);
4493 op = gimple_switch_index (last);
4494 if (TREE_CODE (op) != SSA_NAME)
4497 /* Build a vector of case labels sorted by destination label. */
4498 vec2 = make_tree_vec (n);
4499 for (idx = 0; idx < n; ++idx)
4500 TREE_VEC_ELT (vec2, idx) = gimple_switch_label (last, idx);
4501 qsort (&TREE_VEC_ELT (vec2, 0), n, sizeof (tree), compare_case_labels);
4503 for (idx = 0; idx < n; ++idx)
4506 tree cl = TREE_VEC_ELT (vec2, idx);
4508 min = CASE_LOW (cl);
4509 max = CASE_HIGH (cl);
4511 /* If there are multiple case labels with the same destination
4512 we need to combine them to a single value range for the edge. */
4514 && CASE_LABEL (cl) == CASE_LABEL (TREE_VEC_ELT (vec2, idx + 1)))
4516 /* Skip labels until the last of the group. */
4520 && CASE_LABEL (cl) == CASE_LABEL (TREE_VEC_ELT (vec2, idx)));
4523 /* Pick up the maximum of the case label range. */
4524 if (CASE_HIGH (TREE_VEC_ELT (vec2, idx)))
4525 max = CASE_HIGH (TREE_VEC_ELT (vec2, idx));
4527 max = CASE_LOW (TREE_VEC_ELT (vec2, idx));
4530 /* Nothing to do if the range includes the default label until we
4531 can register anti-ranges. */
4532 if (min == NULL_TREE)
4535 /* Find the edge to register the assert expr on. */
4536 e = find_edge (bb, label_to_block (CASE_LABEL (cl)));
4538 /* Register the necessary assertions for the operand in the
4540 need_assert |= register_edge_assert_for (op, e, bsi,
4541 max ? GE_EXPR : EQ_EXPR,
4543 fold_convert (TREE_TYPE (op),
4547 need_assert |= register_edge_assert_for (op, e, bsi, LE_EXPR,
4549 fold_convert (TREE_TYPE (op),
4558 /* Traverse all the statements in block BB looking for statements that
4559 may generate useful assertions for the SSA names in their operand.
4560 If a statement produces a useful assertion A for name N_i, then the
4561 list of assertions already generated for N_i is scanned to
4562 determine if A is actually needed.
4564 If N_i already had the assertion A at a location dominating the
4565 current location, then nothing needs to be done. Otherwise, the
4566 new location for A is recorded instead.
4568 1- For every statement S in BB, all the variables used by S are
4569 added to bitmap FOUND_IN_SUBGRAPH.
4571 2- If statement S uses an operand N in a way that exposes a known
4572 value range for N, then if N was not already generated by an
4573 ASSERT_EXPR, create a new assert location for N. For instance,
4574 if N is a pointer and the statement dereferences it, we can
4575 assume that N is not NULL.
4577 3- COND_EXPRs are a special case of #2. We can derive range
4578 information from the predicate but need to insert different
4579 ASSERT_EXPRs for each of the sub-graphs rooted at the
4580 conditional block. If the last statement of BB is a conditional
4581 expression of the form 'X op Y', then
4583 a) Remove X and Y from the set FOUND_IN_SUBGRAPH.
4585 b) If the conditional is the only entry point to the sub-graph
4586 corresponding to the THEN_CLAUSE, recurse into it. On
4587 return, if X and/or Y are marked in FOUND_IN_SUBGRAPH, then
4588 an ASSERT_EXPR is added for the corresponding variable.
4590 c) Repeat step (b) on the ELSE_CLAUSE.
4592 d) Mark X and Y in FOUND_IN_SUBGRAPH.
4601 In this case, an assertion on the THEN clause is useful to
4602 determine that 'a' is always 9 on that edge. However, an assertion
4603 on the ELSE clause would be unnecessary.
4605 4- If BB does not end in a conditional expression, then we recurse
4606 into BB's dominator children.
4608 At the end of the recursive traversal, every SSA name will have a
4609 list of locations where ASSERT_EXPRs should be added. When a new
4610 location for name N is found, it is registered by calling
4611 register_new_assert_for. That function keeps track of all the
4612 registered assertions to prevent adding unnecessary assertions.
4613 For instance, if a pointer P_4 is dereferenced more than once in a
4614 dominator tree, only the location dominating all the dereference of
4615 P_4 will receive an ASSERT_EXPR.
4617 If this function returns true, then it means that there are names
4618 for which we need to generate ASSERT_EXPRs. Those assertions are
4619 inserted by process_assert_insertions. */
4622 find_assert_locations_1 (basic_block bb, sbitmap live)
4624 gimple_stmt_iterator si;
4629 need_assert = false;
4630 last = last_stmt (bb);
4632 /* If BB's last statement is a conditional statement involving integer
4633 operands, determine if we need to add ASSERT_EXPRs. */
4635 && gimple_code (last) == GIMPLE_COND
4636 && !fp_predicate (last)
4637 && !ZERO_SSA_OPERANDS (last, SSA_OP_USE))
4638 need_assert |= find_conditional_asserts (bb, last);
4640 /* If BB's last statement is a switch statement involving integer
4641 operands, determine if we need to add ASSERT_EXPRs. */
4643 && gimple_code (last) == GIMPLE_SWITCH
4644 && !ZERO_SSA_OPERANDS (last, SSA_OP_USE))
4645 need_assert |= find_switch_asserts (bb, last);
4647 /* Traverse all the statements in BB marking used names and looking
4648 for statements that may infer assertions for their used operands. */
4649 for (si = gsi_start_bb (bb); !gsi_end_p (si); gsi_next (&si))
4655 stmt = gsi_stmt (si);
4657 /* See if we can derive an assertion for any of STMT's operands. */
4658 FOR_EACH_SSA_TREE_OPERAND (op, stmt, i, SSA_OP_USE)
4661 enum tree_code comp_code;
4663 /* Mark OP in our live bitmap. */
4664 SET_BIT (live, SSA_NAME_VERSION (op));
4666 /* If OP is used in such a way that we can infer a value
4667 range for it, and we don't find a previous assertion for
4668 it, create a new assertion location node for OP. */
4669 if (infer_value_range (stmt, op, &comp_code, &value))
4671 /* If we are able to infer a nonzero value range for OP,
4672 then walk backwards through the use-def chain to see if OP
4673 was set via a typecast.
4675 If so, then we can also infer a nonzero value range
4676 for the operand of the NOP_EXPR. */
4677 if (comp_code == NE_EXPR && integer_zerop (value))
4680 gimple def_stmt = SSA_NAME_DEF_STMT (t);
4682 while (is_gimple_assign (def_stmt)
4683 && gimple_assign_rhs_code (def_stmt) == NOP_EXPR
4685 (gimple_assign_rhs1 (def_stmt)) == SSA_NAME
4687 (TREE_TYPE (gimple_assign_rhs1 (def_stmt))))
4689 t = gimple_assign_rhs1 (def_stmt);
4690 def_stmt = SSA_NAME_DEF_STMT (t);
4692 /* Note we want to register the assert for the
4693 operand of the NOP_EXPR after SI, not after the
4695 if (! has_single_use (t))
4697 register_new_assert_for (t, t, comp_code, value,
4704 /* If OP is used only once, namely in this STMT, don't
4705 bother creating an ASSERT_EXPR for it. Such an
4706 ASSERT_EXPR would do nothing but increase compile time. */
4707 if (!has_single_use (op))
4709 register_new_assert_for (op, op, comp_code, value,
4717 /* Traverse all PHI nodes in BB marking used operands. */
4718 for (si = gsi_start_phis (bb); !gsi_end_p(si); gsi_next (&si))
4720 use_operand_p arg_p;
4722 phi = gsi_stmt (si);
4724 FOR_EACH_PHI_ARG (arg_p, phi, i, SSA_OP_USE)
4726 tree arg = USE_FROM_PTR (arg_p);
4727 if (TREE_CODE (arg) == SSA_NAME)
4728 SET_BIT (live, SSA_NAME_VERSION (arg));
4735 /* Do an RPO walk over the function computing SSA name liveness
4736 on-the-fly and deciding on assert expressions to insert.
4737 Returns true if there are assert expressions to be inserted. */
4740 find_assert_locations (void)
4742 int *rpo = XCNEWVEC (int, last_basic_block + NUM_FIXED_BLOCKS);
4743 int *bb_rpo = XCNEWVEC (int, last_basic_block + NUM_FIXED_BLOCKS);
4744 int *last_rpo = XCNEWVEC (int, last_basic_block + NUM_FIXED_BLOCKS);
4748 live = XCNEWVEC (sbitmap, last_basic_block + NUM_FIXED_BLOCKS);
4749 rpo_cnt = pre_and_rev_post_order_compute (NULL, rpo, false);
4750 for (i = 0; i < rpo_cnt; ++i)
4753 need_asserts = false;
4754 for (i = rpo_cnt-1; i >= 0; --i)
4756 basic_block bb = BASIC_BLOCK (rpo[i]);
4762 live[rpo[i]] = sbitmap_alloc (num_ssa_names);
4763 sbitmap_zero (live[rpo[i]]);
4766 /* Process BB and update the live information with uses in
4768 need_asserts |= find_assert_locations_1 (bb, live[rpo[i]]);
4770 /* Merge liveness into the predecessor blocks and free it. */
4771 if (!sbitmap_empty_p (live[rpo[i]]))
4774 FOR_EACH_EDGE (e, ei, bb->preds)
4776 int pred = e->src->index;
4777 if (e->flags & EDGE_DFS_BACK)
4782 live[pred] = sbitmap_alloc (num_ssa_names);
4783 sbitmap_zero (live[pred]);
4785 sbitmap_a_or_b (live[pred], live[pred], live[rpo[i]]);
4787 if (bb_rpo[pred] < pred_rpo)
4788 pred_rpo = bb_rpo[pred];
4791 /* Record the RPO number of the last visited block that needs
4792 live information from this block. */
4793 last_rpo[rpo[i]] = pred_rpo;
4797 sbitmap_free (live[rpo[i]]);
4798 live[rpo[i]] = NULL;
4801 /* We can free all successors live bitmaps if all their
4802 predecessors have been visited already. */
4803 FOR_EACH_EDGE (e, ei, bb->succs)
4804 if (last_rpo[e->dest->index] == i
4805 && live[e->dest->index])
4807 sbitmap_free (live[e->dest->index]);
4808 live[e->dest->index] = NULL;
4813 XDELETEVEC (bb_rpo);
4814 XDELETEVEC (last_rpo);
4815 for (i = 0; i < last_basic_block + NUM_FIXED_BLOCKS; ++i)
4817 sbitmap_free (live[i]);
4820 return need_asserts;
4823 /* Create an ASSERT_EXPR for NAME and insert it in the location
4824 indicated by LOC. Return true if we made any edge insertions. */
4827 process_assert_insertions_for (tree name, assert_locus_t loc)
4829 /* Build the comparison expression NAME_i COMP_CODE VAL. */
4836 cond = build2 (loc->comp_code, boolean_type_node, loc->expr, loc->val);
4837 assert_stmt = build_assert_expr_for (cond, name);
4840 /* We have been asked to insert the assertion on an edge. This
4841 is used only by COND_EXPR and SWITCH_EXPR assertions. */
4842 #if defined ENABLE_CHECKING
4843 gcc_assert (gimple_code (gsi_stmt (loc->si)) == GIMPLE_COND
4844 || gimple_code (gsi_stmt (loc->si)) == GIMPLE_SWITCH);
4847 gsi_insert_on_edge (loc->e, assert_stmt);
4851 /* Otherwise, we can insert right after LOC->SI iff the
4852 statement must not be the last statement in the block. */
4853 stmt = gsi_stmt (loc->si);
4854 if (!stmt_ends_bb_p (stmt))
4856 gsi_insert_after (&loc->si, assert_stmt, GSI_SAME_STMT);
4860 /* If STMT must be the last statement in BB, we can only insert new
4861 assertions on the non-abnormal edge out of BB. Note that since
4862 STMT is not control flow, there may only be one non-abnormal edge
4864 FOR_EACH_EDGE (e, ei, loc->bb->succs)
4865 if (!(e->flags & EDGE_ABNORMAL))
4867 gsi_insert_on_edge (e, assert_stmt);
4875 /* Process all the insertions registered for every name N_i registered
4876 in NEED_ASSERT_FOR. The list of assertions to be inserted are
4877 found in ASSERTS_FOR[i]. */
4880 process_assert_insertions (void)
4884 bool update_edges_p = false;
4885 int num_asserts = 0;
4887 if (dump_file && (dump_flags & TDF_DETAILS))
4888 dump_all_asserts (dump_file);
4890 EXECUTE_IF_SET_IN_BITMAP (need_assert_for, 0, i, bi)
4892 assert_locus_t loc = asserts_for[i];
4897 assert_locus_t next = loc->next;
4898 update_edges_p |= process_assert_insertions_for (ssa_name (i), loc);
4906 gsi_commit_edge_inserts ();
4908 statistics_counter_event (cfun, "Number of ASSERT_EXPR expressions inserted",
4913 /* Traverse the flowgraph looking for conditional jumps to insert range
4914 expressions. These range expressions are meant to provide information
4915 to optimizations that need to reason in terms of value ranges. They
4916 will not be expanded into RTL. For instance, given:
4925 this pass will transform the code into:
4931 x = ASSERT_EXPR <x, x < y>
4936 y = ASSERT_EXPR <y, x <= y>
4940 The idea is that once copy and constant propagation have run, other
4941 optimizations will be able to determine what ranges of values can 'x'
4942 take in different paths of the code, simply by checking the reaching
4943 definition of 'x'. */
4946 insert_range_assertions (void)
4948 need_assert_for = BITMAP_ALLOC (NULL);
4949 asserts_for = XCNEWVEC (assert_locus_t, num_ssa_names);
4951 calculate_dominance_info (CDI_DOMINATORS);
4953 if (find_assert_locations ())
4955 process_assert_insertions ();
4956 update_ssa (TODO_update_ssa_no_phi);
4959 if (dump_file && (dump_flags & TDF_DETAILS))
4961 fprintf (dump_file, "\nSSA form after inserting ASSERT_EXPRs\n");
4962 dump_function_to_file (current_function_decl, dump_file, dump_flags);
4966 BITMAP_FREE (need_assert_for);
4969 /* Checks one ARRAY_REF in REF, located at LOCUS. Ignores flexible arrays
4970 and "struct" hacks. If VRP can determine that the
4971 array subscript is a constant, check if it is outside valid
4972 range. If the array subscript is a RANGE, warn if it is
4973 non-overlapping with valid range.
4974 IGNORE_OFF_BY_ONE is true if the ARRAY_REF is inside a ADDR_EXPR. */
4977 check_array_ref (tree ref, location_t location, bool ignore_off_by_one)
4979 value_range_t* vr = NULL;
4980 tree low_sub, up_sub;
4981 tree low_bound, up_bound = array_ref_up_bound (ref);
4983 low_sub = up_sub = TREE_OPERAND (ref, 1);
4985 if (!up_bound || TREE_NO_WARNING (ref)
4986 || TREE_CODE (up_bound) != INTEGER_CST
4987 /* Can not check flexible arrays. */
4988 || (TYPE_SIZE (TREE_TYPE (ref)) == NULL_TREE
4989 && TYPE_DOMAIN (TREE_TYPE (ref)) != NULL_TREE
4990 && TYPE_MAX_VALUE (TYPE_DOMAIN (TREE_TYPE (ref))) == NULL_TREE)
4991 /* Accesses after the end of arrays of size 0 (gcc
4992 extension) and 1 are likely intentional ("struct
4994 || compare_tree_int (up_bound, 1) <= 0)
4997 low_bound = array_ref_low_bound (ref);
4999 if (TREE_CODE (low_sub) == SSA_NAME)
5001 vr = get_value_range (low_sub);
5002 if (vr->type == VR_RANGE || vr->type == VR_ANTI_RANGE)
5004 low_sub = vr->type == VR_RANGE ? vr->max : vr->min;
5005 up_sub = vr->type == VR_RANGE ? vr->min : vr->max;
5009 if (vr && vr->type == VR_ANTI_RANGE)
5011 if (TREE_CODE (up_sub) == INTEGER_CST
5012 && tree_int_cst_lt (up_bound, up_sub)
5013 && TREE_CODE (low_sub) == INTEGER_CST
5014 && tree_int_cst_lt (low_sub, low_bound))
5016 warning_at (location, OPT_Warray_bounds,
5017 "array subscript is outside array bounds");
5018 TREE_NO_WARNING (ref) = 1;
5021 else if (TREE_CODE (up_sub) == INTEGER_CST
5022 && tree_int_cst_lt (up_bound, up_sub)
5023 && !tree_int_cst_equal (up_bound, up_sub)
5024 && (!ignore_off_by_one
5025 || !tree_int_cst_equal (int_const_binop (PLUS_EXPR,
5031 warning_at (location, OPT_Warray_bounds,
5032 "array subscript is above array bounds");
5033 TREE_NO_WARNING (ref) = 1;
5035 else if (TREE_CODE (low_sub) == INTEGER_CST
5036 && tree_int_cst_lt (low_sub, low_bound))
5038 warning_at (location, OPT_Warray_bounds,
5039 "array subscript is below array bounds");
5040 TREE_NO_WARNING (ref) = 1;
5044 /* Searches if the expr T, located at LOCATION computes
5045 address of an ARRAY_REF, and call check_array_ref on it. */
5048 search_for_addr_array (tree t, location_t location)
5050 while (TREE_CODE (t) == SSA_NAME)
5052 gimple g = SSA_NAME_DEF_STMT (t);
5054 if (gimple_code (g) != GIMPLE_ASSIGN)
5057 if (get_gimple_rhs_class (gimple_assign_rhs_code (g))
5058 != GIMPLE_SINGLE_RHS)
5061 t = gimple_assign_rhs1 (g);
5065 /* We are only interested in addresses of ARRAY_REF's. */
5066 if (TREE_CODE (t) != ADDR_EXPR)
5069 /* Check each ARRAY_REFs in the reference chain. */
5072 if (TREE_CODE (t) == ARRAY_REF)
5073 check_array_ref (t, location, true /*ignore_off_by_one*/);
5075 t = TREE_OPERAND (t, 0);
5077 while (handled_component_p (t));
5080 /* walk_tree() callback that checks if *TP is
5081 an ARRAY_REF inside an ADDR_EXPR (in which an array
5082 subscript one outside the valid range is allowed). Call
5083 check_array_ref for each ARRAY_REF found. The location is
5087 check_array_bounds (tree *tp, int *walk_subtree, void *data)
5090 struct walk_stmt_info *wi = (struct walk_stmt_info *) data;
5091 const location_t *location = (const location_t *) wi->info;
5093 *walk_subtree = TRUE;
5095 if (TREE_CODE (t) == ARRAY_REF)
5096 check_array_ref (t, *location, false /*ignore_off_by_one*/);
5098 if (TREE_CODE (t) == INDIRECT_REF
5099 || (TREE_CODE (t) == RETURN_EXPR && TREE_OPERAND (t, 0)))
5100 search_for_addr_array (TREE_OPERAND (t, 0), *location);
5102 if (TREE_CODE (t) == ADDR_EXPR)
5103 *walk_subtree = FALSE;
5108 /* Walk over all statements of all reachable BBs and call check_array_bounds
5112 check_all_array_refs (void)
5115 gimple_stmt_iterator si;
5119 /* Skip bb's that are clearly unreachable. */
5120 if (single_pred_p (bb))
5123 bool reachable = true;
5125 edge e = EDGE_PRED (bb, 0);
5126 basic_block pred_bb = e->src;
5129 for (i = 0; VEC_iterate (edge, to_remove_edges, i, e2); ++i)
5139 if (!gsi_end_p (gsi_last_bb (pred_bb)))
5140 ls = gsi_stmt (gsi_last_bb (pred_bb));
5142 if (ls && gimple_code (ls) == GIMPLE_COND
5143 && ((gimple_cond_false_p (ls)
5144 && (EDGE_PRED (bb, 0)->flags & EDGE_TRUE_VALUE))
5145 || (gimple_cond_true_p (ls)
5146 && (EDGE_PRED (bb, 0)->flags & EDGE_FALSE_VALUE))))
5149 for (si = gsi_start_bb (bb); !gsi_end_p (si); gsi_next (&si))
5151 gimple stmt = gsi_stmt (si);
5152 struct walk_stmt_info wi;
5153 if (!gimple_has_location (stmt))
5156 if (is_gimple_call (stmt))
5159 size_t n = gimple_call_num_args (stmt);
5160 for (i = 0; i < n; i++)
5162 tree arg = gimple_call_arg (stmt, i);
5163 search_for_addr_array (arg, gimple_location (stmt));
5168 memset (&wi, 0, sizeof (wi));
5169 wi.info = CONST_CAST (void *, (const void *)
5170 gimple_location_ptr (stmt));
5172 walk_gimple_op (gsi_stmt (si),
5180 /* Convert range assertion expressions into the implied copies and
5181 copy propagate away the copies. Doing the trivial copy propagation
5182 here avoids the need to run the full copy propagation pass after
5185 FIXME, this will eventually lead to copy propagation removing the
5186 names that had useful range information attached to them. For
5187 instance, if we had the assertion N_i = ASSERT_EXPR <N_j, N_j > 3>,
5188 then N_i will have the range [3, +INF].
5190 However, by converting the assertion into the implied copy
5191 operation N_i = N_j, we will then copy-propagate N_j into the uses
5192 of N_i and lose the range information. We may want to hold on to
5193 ASSERT_EXPRs a little while longer as the ranges could be used in
5194 things like jump threading.
5196 The problem with keeping ASSERT_EXPRs around is that passes after
5197 VRP need to handle them appropriately.
5199 Another approach would be to make the range information a first
5200 class property of the SSA_NAME so that it can be queried from
5201 any pass. This is made somewhat more complex by the need for
5202 multiple ranges to be associated with one SSA_NAME. */
5205 remove_range_assertions (void)
5208 gimple_stmt_iterator si;
5210 /* Note that the BSI iterator bump happens at the bottom of the
5211 loop and no bump is necessary if we're removing the statement
5212 referenced by the current BSI. */
5214 for (si = gsi_start_bb (bb); !gsi_end_p (si);)
5216 gimple stmt = gsi_stmt (si);
5219 if (is_gimple_assign (stmt)
5220 && gimple_assign_rhs_code (stmt) == ASSERT_EXPR)
5222 tree rhs = gimple_assign_rhs1 (stmt);
5224 tree cond = fold (ASSERT_EXPR_COND (rhs));
5225 use_operand_p use_p;
5226 imm_use_iterator iter;
5228 gcc_assert (cond != boolean_false_node);
5230 /* Propagate the RHS into every use of the LHS. */
5231 var = ASSERT_EXPR_VAR (rhs);
5232 FOR_EACH_IMM_USE_STMT (use_stmt, iter,
5233 gimple_assign_lhs (stmt))
5234 FOR_EACH_IMM_USE_ON_STMT (use_p, iter)
5236 SET_USE (use_p, var);
5237 gcc_assert (TREE_CODE (var) == SSA_NAME);
5240 /* And finally, remove the copy, it is not needed. */
5241 gsi_remove (&si, true);
5242 release_defs (stmt);
5250 /* Return true if STMT is interesting for VRP. */
5253 stmt_interesting_for_vrp (gimple stmt)
5255 if (gimple_code (stmt) == GIMPLE_PHI
5256 && is_gimple_reg (gimple_phi_result (stmt))
5257 && (INTEGRAL_TYPE_P (TREE_TYPE (gimple_phi_result (stmt)))
5258 || POINTER_TYPE_P (TREE_TYPE (gimple_phi_result (stmt)))))
5260 else if (is_gimple_assign (stmt) || is_gimple_call (stmt))
5262 tree lhs = gimple_get_lhs (stmt);
5264 /* In general, assignments with virtual operands are not useful
5265 for deriving ranges, with the obvious exception of calls to
5266 builtin functions. */
5267 if (lhs && TREE_CODE (lhs) == SSA_NAME
5268 && (INTEGRAL_TYPE_P (TREE_TYPE (lhs))
5269 || POINTER_TYPE_P (TREE_TYPE (lhs)))
5270 && ((is_gimple_call (stmt)
5271 && gimple_call_fndecl (stmt) != NULL_TREE
5272 && DECL_IS_BUILTIN (gimple_call_fndecl (stmt)))
5273 || !gimple_vuse (stmt)))
5276 else if (gimple_code (stmt) == GIMPLE_COND
5277 || gimple_code (stmt) == GIMPLE_SWITCH)
5284 /* Initialize local data structures for VRP. */
5287 vrp_initialize (void)
5291 vr_value = XCNEWVEC (value_range_t *, num_ssa_names);
5292 vr_phi_edge_counts = XCNEWVEC (int, num_ssa_names);
5296 gimple_stmt_iterator si;
5298 for (si = gsi_start_phis (bb); !gsi_end_p (si); gsi_next (&si))
5300 gimple phi = gsi_stmt (si);
5301 if (!stmt_interesting_for_vrp (phi))
5303 tree lhs = PHI_RESULT (phi);
5304 set_value_range_to_varying (get_value_range (lhs));
5305 prop_set_simulate_again (phi, false);
5308 prop_set_simulate_again (phi, true);
5311 for (si = gsi_start_bb (bb); !gsi_end_p (si); gsi_next (&si))
5313 gimple stmt = gsi_stmt (si);
5315 if (!stmt_interesting_for_vrp (stmt))
5319 FOR_EACH_SSA_TREE_OPERAND (def, stmt, i, SSA_OP_DEF)
5320 set_value_range_to_varying (get_value_range (def));
5321 prop_set_simulate_again (stmt, false);
5325 prop_set_simulate_again (stmt, true);
5332 /* Visit assignment STMT. If it produces an interesting range, record
5333 the SSA name in *OUTPUT_P. */
5335 static enum ssa_prop_result
5336 vrp_visit_assignment_or_call (gimple stmt, tree *output_p)
5340 enum gimple_code code = gimple_code (stmt);
5341 lhs = gimple_get_lhs (stmt);
5343 /* We only keep track of ranges in integral and pointer types. */
5344 if (TREE_CODE (lhs) == SSA_NAME
5345 && ((INTEGRAL_TYPE_P (TREE_TYPE (lhs))
5346 /* It is valid to have NULL MIN/MAX values on a type. See
5347 build_range_type. */
5348 && TYPE_MIN_VALUE (TREE_TYPE (lhs))
5349 && TYPE_MAX_VALUE (TREE_TYPE (lhs)))
5350 || POINTER_TYPE_P (TREE_TYPE (lhs))))
5353 value_range_t new_vr = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
5355 if (code == GIMPLE_CALL)
5356 extract_range_basic (&new_vr, stmt);
5358 extract_range_from_assignment (&new_vr, stmt);
5360 /* If STMT is inside a loop, we may be able to know something
5361 else about the range of LHS by examining scalar evolution
5363 if (current_loops && (l = loop_containing_stmt (stmt)))
5364 adjust_range_with_scev (&new_vr, l, stmt, lhs);
5366 if (update_value_range (lhs, &new_vr))
5370 if (dump_file && (dump_flags & TDF_DETAILS))
5372 fprintf (dump_file, "Found new range for ");
5373 print_generic_expr (dump_file, lhs, 0);
5374 fprintf (dump_file, ": ");
5375 dump_value_range (dump_file, &new_vr);
5376 fprintf (dump_file, "\n\n");
5379 if (new_vr.type == VR_VARYING)
5380 return SSA_PROP_VARYING;
5382 return SSA_PROP_INTERESTING;
5385 return SSA_PROP_NOT_INTERESTING;
5388 /* Every other statement produces no useful ranges. */
5389 FOR_EACH_SSA_TREE_OPERAND (def, stmt, iter, SSA_OP_DEF)
5390 set_value_range_to_varying (get_value_range (def));
5392 return SSA_PROP_VARYING;
5395 /* Helper that gets the value range of the SSA_NAME with version I
5396 or a symbolic range containing the SSA_NAME only if the value range
5397 is varying or undefined. */
5399 static inline value_range_t
5400 get_vr_for_comparison (int i)
5402 value_range_t vr = *(vr_value[i]);
5404 /* If name N_i does not have a valid range, use N_i as its own
5405 range. This allows us to compare against names that may
5406 have N_i in their ranges. */
5407 if (vr.type == VR_VARYING || vr.type == VR_UNDEFINED)
5410 vr.min = ssa_name (i);
5411 vr.max = ssa_name (i);
5417 /* Compare all the value ranges for names equivalent to VAR with VAL
5418 using comparison code COMP. Return the same value returned by
5419 compare_range_with_value, including the setting of
5420 *STRICT_OVERFLOW_P. */
5423 compare_name_with_value (enum tree_code comp, tree var, tree val,
5424 bool *strict_overflow_p)
5430 int used_strict_overflow;
5432 value_range_t equiv_vr;
5434 /* Get the set of equivalences for VAR. */
5435 e = get_value_range (var)->equiv;
5437 /* Start at -1. Set it to 0 if we do a comparison without relying
5438 on overflow, or 1 if all comparisons rely on overflow. */
5439 used_strict_overflow = -1;
5441 /* Compare vars' value range with val. */
5442 equiv_vr = get_vr_for_comparison (SSA_NAME_VERSION (var));
5444 retval = compare_range_with_value (comp, &equiv_vr, val, &sop);
5446 used_strict_overflow = sop ? 1 : 0;
5448 /* If the equiv set is empty we have done all work we need to do. */
5452 && used_strict_overflow > 0)
5453 *strict_overflow_p = true;
5457 EXECUTE_IF_SET_IN_BITMAP (e, 0, i, bi)
5459 equiv_vr = get_vr_for_comparison (i);
5461 t = compare_range_with_value (comp, &equiv_vr, val, &sop);
5464 /* If we get different answers from different members
5465 of the equivalence set this check must be in a dead
5466 code region. Folding it to a trap representation
5467 would be correct here. For now just return don't-know. */
5477 used_strict_overflow = 0;
5478 else if (used_strict_overflow < 0)
5479 used_strict_overflow = 1;
5484 && used_strict_overflow > 0)
5485 *strict_overflow_p = true;
5491 /* Given a comparison code COMP and names N1 and N2, compare all the
5492 ranges equivalent to N1 against all the ranges equivalent to N2
5493 to determine the value of N1 COMP N2. Return the same value
5494 returned by compare_ranges. Set *STRICT_OVERFLOW_P to indicate
5495 whether we relied on an overflow infinity in the comparison. */
5499 compare_names (enum tree_code comp, tree n1, tree n2,
5500 bool *strict_overflow_p)
5504 bitmap_iterator bi1, bi2;
5506 int used_strict_overflow;
5507 static bitmap_obstack *s_obstack = NULL;
5508 static bitmap s_e1 = NULL, s_e2 = NULL;
5510 /* Compare the ranges of every name equivalent to N1 against the
5511 ranges of every name equivalent to N2. */
5512 e1 = get_value_range (n1)->equiv;
5513 e2 = get_value_range (n2)->equiv;
5515 /* Use the fake bitmaps if e1 or e2 are not available. */
5516 if (s_obstack == NULL)
5518 s_obstack = XNEW (bitmap_obstack);
5519 bitmap_obstack_initialize (s_obstack);
5520 s_e1 = BITMAP_ALLOC (s_obstack);
5521 s_e2 = BITMAP_ALLOC (s_obstack);
5528 /* Add N1 and N2 to their own set of equivalences to avoid
5529 duplicating the body of the loop just to check N1 and N2
5531 bitmap_set_bit (e1, SSA_NAME_VERSION (n1));
5532 bitmap_set_bit (e2, SSA_NAME_VERSION (n2));
5534 /* If the equivalence sets have a common intersection, then the two
5535 names can be compared without checking their ranges. */
5536 if (bitmap_intersect_p (e1, e2))
5538 bitmap_clear_bit (e1, SSA_NAME_VERSION (n1));
5539 bitmap_clear_bit (e2, SSA_NAME_VERSION (n2));
5541 return (comp == EQ_EXPR || comp == GE_EXPR || comp == LE_EXPR)
5543 : boolean_false_node;
5546 /* Start at -1. Set it to 0 if we do a comparison without relying
5547 on overflow, or 1 if all comparisons rely on overflow. */
5548 used_strict_overflow = -1;
5550 /* Otherwise, compare all the equivalent ranges. First, add N1 and
5551 N2 to their own set of equivalences to avoid duplicating the body
5552 of the loop just to check N1 and N2 ranges. */
5553 EXECUTE_IF_SET_IN_BITMAP (e1, 0, i1, bi1)
5555 value_range_t vr1 = get_vr_for_comparison (i1);
5557 t = retval = NULL_TREE;
5558 EXECUTE_IF_SET_IN_BITMAP (e2, 0, i2, bi2)
5562 value_range_t vr2 = get_vr_for_comparison (i2);
5564 t = compare_ranges (comp, &vr1, &vr2, &sop);
5567 /* If we get different answers from different members
5568 of the equivalence set this check must be in a dead
5569 code region. Folding it to a trap representation
5570 would be correct here. For now just return don't-know. */
5574 bitmap_clear_bit (e1, SSA_NAME_VERSION (n1));
5575 bitmap_clear_bit (e2, SSA_NAME_VERSION (n2));
5581 used_strict_overflow = 0;
5582 else if (used_strict_overflow < 0)
5583 used_strict_overflow = 1;
5589 bitmap_clear_bit (e1, SSA_NAME_VERSION (n1));
5590 bitmap_clear_bit (e2, SSA_NAME_VERSION (n2));
5591 if (used_strict_overflow > 0)
5592 *strict_overflow_p = true;
5597 /* None of the equivalent ranges are useful in computing this
5599 bitmap_clear_bit (e1, SSA_NAME_VERSION (n1));
5600 bitmap_clear_bit (e2, SSA_NAME_VERSION (n2));
5604 /* Helper function for vrp_evaluate_conditional_warnv. */
5607 vrp_evaluate_conditional_warnv_with_ops_using_ranges (enum tree_code code,
5609 bool * strict_overflow_p)
5611 value_range_t *vr0, *vr1;
5613 vr0 = (TREE_CODE (op0) == SSA_NAME) ? get_value_range (op0) : NULL;
5614 vr1 = (TREE_CODE (op1) == SSA_NAME) ? get_value_range (op1) : NULL;
5617 return compare_ranges (code, vr0, vr1, strict_overflow_p);
5618 else if (vr0 && vr1 == NULL)
5619 return compare_range_with_value (code, vr0, op1, strict_overflow_p);
5620 else if (vr0 == NULL && vr1)
5621 return (compare_range_with_value
5622 (swap_tree_comparison (code), vr1, op0, strict_overflow_p));
5626 /* Helper function for vrp_evaluate_conditional_warnv. */
5629 vrp_evaluate_conditional_warnv_with_ops (enum tree_code code, tree op0,
5630 tree op1, bool use_equiv_p,
5631 bool *strict_overflow_p, bool *only_ranges)
5635 *only_ranges = true;
5637 /* We only deal with integral and pointer types. */
5638 if (!INTEGRAL_TYPE_P (TREE_TYPE (op0))
5639 && !POINTER_TYPE_P (TREE_TYPE (op0)))
5645 && (ret = vrp_evaluate_conditional_warnv_with_ops_using_ranges
5646 (code, op0, op1, strict_overflow_p)))
5648 *only_ranges = false;
5649 if (TREE_CODE (op0) == SSA_NAME && TREE_CODE (op1) == SSA_NAME)
5650 return compare_names (code, op0, op1, strict_overflow_p);
5651 else if (TREE_CODE (op0) == SSA_NAME)
5652 return compare_name_with_value (code, op0, op1, strict_overflow_p);
5653 else if (TREE_CODE (op1) == SSA_NAME)
5654 return (compare_name_with_value
5655 (swap_tree_comparison (code), op1, op0, strict_overflow_p));
5658 return vrp_evaluate_conditional_warnv_with_ops_using_ranges (code, op0, op1,
5663 /* Given (CODE OP0 OP1) within STMT, try to simplify it based on value range
5664 information. Return NULL if the conditional can not be evaluated.
5665 The ranges of all the names equivalent with the operands in COND
5666 will be used when trying to compute the value. If the result is
5667 based on undefined signed overflow, issue a warning if
5671 vrp_evaluate_conditional (enum tree_code code, tree op0, tree op1, gimple stmt)
5678 ret = vrp_evaluate_conditional_warnv_with_ops (code, op0, op1, true, &sop,
5683 enum warn_strict_overflow_code wc;
5684 const char* warnmsg;
5686 if (is_gimple_min_invariant (ret))
5688 wc = WARN_STRICT_OVERFLOW_CONDITIONAL;
5689 warnmsg = G_("assuming signed overflow does not occur when "
5690 "simplifying conditional to constant");
5694 wc = WARN_STRICT_OVERFLOW_COMPARISON;
5695 warnmsg = G_("assuming signed overflow does not occur when "
5696 "simplifying conditional");
5699 if (issue_strict_overflow_warning (wc))
5701 location_t location;
5703 if (!gimple_has_location (stmt))
5704 location = input_location;
5706 location = gimple_location (stmt);
5707 warning (OPT_Wstrict_overflow, "%H%s", &location, warnmsg);
5711 if (warn_type_limits
5712 && ret && only_ranges
5713 && TREE_CODE_CLASS (code) == tcc_comparison
5714 && TREE_CODE (op0) == SSA_NAME)
5716 /* If the comparison is being folded and the operand on the LHS
5717 is being compared against a constant value that is outside of
5718 the natural range of OP0's type, then the predicate will
5719 always fold regardless of the value of OP0. If -Wtype-limits
5720 was specified, emit a warning. */
5721 const char *warnmsg = NULL;
5722 tree type = TREE_TYPE (op0);
5723 value_range_t *vr0 = get_value_range (op0);
5725 if (vr0->type != VR_VARYING
5726 && INTEGRAL_TYPE_P (type)
5727 && vrp_val_is_min (vr0->min)
5728 && vrp_val_is_max (vr0->max)
5729 && is_gimple_min_invariant (op1))
5731 if (integer_zerop (ret))
5732 warnmsg = G_("comparison always false due to limited range of "
5735 warnmsg = G_("comparison always true due to limited range of "
5741 location_t location;
5743 if (!gimple_has_location (stmt))
5744 location = input_location;
5746 location = gimple_location (stmt);
5748 warning (OPT_Wtype_limits, "%H%s", &location, warnmsg);
5756 /* Visit conditional statement STMT. If we can determine which edge
5757 will be taken out of STMT's basic block, record it in
5758 *TAKEN_EDGE_P and return SSA_PROP_INTERESTING. Otherwise, return
5759 SSA_PROP_VARYING. */
5761 static enum ssa_prop_result
5762 vrp_visit_cond_stmt (gimple stmt, edge *taken_edge_p)
5767 *taken_edge_p = NULL;
5769 if (dump_file && (dump_flags & TDF_DETAILS))
5774 fprintf (dump_file, "\nVisiting conditional with predicate: ");
5775 print_gimple_stmt (dump_file, stmt, 0, 0);
5776 fprintf (dump_file, "\nWith known ranges\n");
5778 FOR_EACH_SSA_TREE_OPERAND (use, stmt, i, SSA_OP_USE)
5780 fprintf (dump_file, "\t");
5781 print_generic_expr (dump_file, use, 0);
5782 fprintf (dump_file, ": ");
5783 dump_value_range (dump_file, vr_value[SSA_NAME_VERSION (use)]);
5786 fprintf (dump_file, "\n");
5789 /* Compute the value of the predicate COND by checking the known
5790 ranges of each of its operands.
5792 Note that we cannot evaluate all the equivalent ranges here
5793 because those ranges may not yet be final and with the current
5794 propagation strategy, we cannot determine when the value ranges
5795 of the names in the equivalence set have changed.
5797 For instance, given the following code fragment
5801 i_14 = ASSERT_EXPR <i_5, i_5 != 0>
5805 Assume that on the first visit to i_14, i_5 has the temporary
5806 range [8, 8] because the second argument to the PHI function is
5807 not yet executable. We derive the range ~[0, 0] for i_14 and the
5808 equivalence set { i_5 }. So, when we visit 'if (i_14 == 1)' for
5809 the first time, since i_14 is equivalent to the range [8, 8], we
5810 determine that the predicate is always false.
5812 On the next round of propagation, i_13 is determined to be
5813 VARYING, which causes i_5 to drop down to VARYING. So, another
5814 visit to i_14 is scheduled. In this second visit, we compute the
5815 exact same range and equivalence set for i_14, namely ~[0, 0] and
5816 { i_5 }. But we did not have the previous range for i_5
5817 registered, so vrp_visit_assignment thinks that the range for
5818 i_14 has not changed. Therefore, the predicate 'if (i_14 == 1)'
5819 is not visited again, which stops propagation from visiting
5820 statements in the THEN clause of that if().
5822 To properly fix this we would need to keep the previous range
5823 value for the names in the equivalence set. This way we would've
5824 discovered that from one visit to the other i_5 changed from
5825 range [8, 8] to VR_VARYING.
5827 However, fixing this apparent limitation may not be worth the
5828 additional checking. Testing on several code bases (GCC, DLV,
5829 MICO, TRAMP3D and SPEC2000) showed that doing this results in
5830 4 more predicates folded in SPEC. */
5833 val = vrp_evaluate_conditional_warnv_with_ops (gimple_cond_code (stmt),
5834 gimple_cond_lhs (stmt),
5835 gimple_cond_rhs (stmt),
5840 *taken_edge_p = find_taken_edge (gimple_bb (stmt), val);
5843 if (dump_file && (dump_flags & TDF_DETAILS))
5845 "\nIgnoring predicate evaluation because "
5846 "it assumes that signed overflow is undefined");
5851 if (dump_file && (dump_flags & TDF_DETAILS))
5853 fprintf (dump_file, "\nPredicate evaluates to: ");
5854 if (val == NULL_TREE)
5855 fprintf (dump_file, "DON'T KNOW\n");
5857 print_generic_stmt (dump_file, val, 0);
5860 return (*taken_edge_p) ? SSA_PROP_INTERESTING : SSA_PROP_VARYING;
5863 /* Searches the case label vector VEC for the index *IDX of the CASE_LABEL
5864 that includes the value VAL. The search is restricted to the range
5865 [START_IDX, n - 1] where n is the size of VEC.
5867 If there is a CASE_LABEL for VAL, its index is placed in IDX and true is
5870 If there is no CASE_LABEL for VAL and there is one that is larger than VAL,
5871 it is placed in IDX and false is returned.
5873 If VAL is larger than any CASE_LABEL, n is placed on IDX and false is
5877 find_case_label_index (gimple stmt, size_t start_idx, tree val, size_t *idx)
5879 size_t n = gimple_switch_num_labels (stmt);
5882 /* Find case label for minimum of the value range or the next one.
5883 At each iteration we are searching in [low, high - 1]. */
5885 for (low = start_idx, high = n; high != low; )
5889 /* Note that i != high, so we never ask for n. */
5890 size_t i = (high + low) / 2;
5891 t = gimple_switch_label (stmt, i);
5893 /* Cache the result of comparing CASE_LOW and val. */
5894 cmp = tree_int_cst_compare (CASE_LOW (t), val);
5898 /* Ranges cannot be empty. */
5907 if (CASE_HIGH (t) != NULL
5908 && tree_int_cst_compare (CASE_HIGH (t), val) >= 0)
5920 /* Searches the case label vector VEC for the range of CASE_LABELs that is used
5921 for values between MIN and MAX. The first index is placed in MIN_IDX. The
5922 last index is placed in MAX_IDX. If the range of CASE_LABELs is empty
5923 then MAX_IDX < MIN_IDX.
5924 Returns true if the default label is not needed. */
5927 find_case_label_range (gimple stmt, tree min, tree max, size_t *min_idx,
5931 bool min_take_default = !find_case_label_index (stmt, 1, min, &i);
5932 bool max_take_default = !find_case_label_index (stmt, i, max, &j);
5936 && max_take_default)
5938 /* Only the default case label reached.
5939 Return an empty range. */
5946 bool take_default = min_take_default || max_take_default;
5950 if (max_take_default)
5953 /* If the case label range is continuous, we do not need
5954 the default case label. Verify that. */
5955 high = CASE_LOW (gimple_switch_label (stmt, i));
5956 if (CASE_HIGH (gimple_switch_label (stmt, i)))
5957 high = CASE_HIGH (gimple_switch_label (stmt, i));
5958 for (k = i + 1; k <= j; ++k)
5960 low = CASE_LOW (gimple_switch_label (stmt, k));
5961 if (!integer_onep (int_const_binop (MINUS_EXPR, low, high, 0)))
5963 take_default = true;
5967 if (CASE_HIGH (gimple_switch_label (stmt, k)))
5968 high = CASE_HIGH (gimple_switch_label (stmt, k));
5973 return !take_default;
5977 /* Visit switch statement STMT. If we can determine which edge
5978 will be taken out of STMT's basic block, record it in
5979 *TAKEN_EDGE_P and return SSA_PROP_INTERESTING. Otherwise, return
5980 SSA_PROP_VARYING. */
5982 static enum ssa_prop_result
5983 vrp_visit_switch_stmt (gimple stmt, edge *taken_edge_p)
5987 size_t i = 0, j = 0, n;
5990 *taken_edge_p = NULL;
5991 op = gimple_switch_index (stmt);
5992 if (TREE_CODE (op) != SSA_NAME)
5993 return SSA_PROP_VARYING;
5995 vr = get_value_range (op);
5996 if (dump_file && (dump_flags & TDF_DETAILS))
5998 fprintf (dump_file, "\nVisiting switch expression with operand ");
5999 print_generic_expr (dump_file, op, 0);
6000 fprintf (dump_file, " with known range ");
6001 dump_value_range (dump_file, vr);
6002 fprintf (dump_file, "\n");
6005 if (vr->type != VR_RANGE
6006 || symbolic_range_p (vr))
6007 return SSA_PROP_VARYING;
6009 /* Find the single edge that is taken from the switch expression. */
6010 n = gimple_switch_num_labels (stmt);
6012 take_default = !find_case_label_range (stmt, vr->min, vr->max, &i, &j);
6014 /* Check if the range spans no CASE_LABEL. If so, we only reach the default
6018 gcc_assert (take_default);
6019 val = gimple_switch_default_label (stmt);
6023 /* Check if labels with index i to j and maybe the default label
6024 are all reaching the same label. */
6026 val = gimple_switch_label (stmt, i);
6028 && CASE_LABEL (gimple_switch_default_label (stmt))
6029 != CASE_LABEL (val))
6031 if (dump_file && (dump_flags & TDF_DETAILS))
6032 fprintf (dump_file, " not a single destination for this "
6034 return SSA_PROP_VARYING;
6036 for (++i; i <= j; ++i)
6038 if (CASE_LABEL (gimple_switch_label (stmt, i)) != CASE_LABEL (val))
6040 if (dump_file && (dump_flags & TDF_DETAILS))
6041 fprintf (dump_file, " not a single destination for this "
6043 return SSA_PROP_VARYING;
6048 *taken_edge_p = find_edge (gimple_bb (stmt),
6049 label_to_block (CASE_LABEL (val)));
6051 if (dump_file && (dump_flags & TDF_DETAILS))
6053 fprintf (dump_file, " will take edge to ");
6054 print_generic_stmt (dump_file, CASE_LABEL (val), 0);
6057 return SSA_PROP_INTERESTING;
6061 /* Evaluate statement STMT. If the statement produces a useful range,
6062 return SSA_PROP_INTERESTING and record the SSA name with the
6063 interesting range into *OUTPUT_P.
6065 If STMT is a conditional branch and we can determine its truth
6066 value, the taken edge is recorded in *TAKEN_EDGE_P.
6068 If STMT produces a varying value, return SSA_PROP_VARYING. */
6070 static enum ssa_prop_result
6071 vrp_visit_stmt (gimple stmt, edge *taken_edge_p, tree *output_p)
6076 if (dump_file && (dump_flags & TDF_DETAILS))
6078 fprintf (dump_file, "\nVisiting statement:\n");
6079 print_gimple_stmt (dump_file, stmt, 0, dump_flags);
6080 fprintf (dump_file, "\n");
6083 if (is_gimple_assign (stmt) || is_gimple_call (stmt))
6085 /* In general, assignments with virtual operands are not useful
6086 for deriving ranges, with the obvious exception of calls to
6087 builtin functions. */
6089 if ((is_gimple_call (stmt)
6090 && gimple_call_fndecl (stmt) != NULL_TREE
6091 && DECL_IS_BUILTIN (gimple_call_fndecl (stmt)))
6092 || !gimple_vuse (stmt))
6093 return vrp_visit_assignment_or_call (stmt, output_p);
6095 else if (gimple_code (stmt) == GIMPLE_COND)
6096 return vrp_visit_cond_stmt (stmt, taken_edge_p);
6097 else if (gimple_code (stmt) == GIMPLE_SWITCH)
6098 return vrp_visit_switch_stmt (stmt, taken_edge_p);
6100 /* All other statements produce nothing of interest for VRP, so mark
6101 their outputs varying and prevent further simulation. */
6102 FOR_EACH_SSA_TREE_OPERAND (def, stmt, iter, SSA_OP_DEF)
6103 set_value_range_to_varying (get_value_range (def));
6105 return SSA_PROP_VARYING;
6109 /* Meet operation for value ranges. Given two value ranges VR0 and
6110 VR1, store in VR0 a range that contains both VR0 and VR1. This
6111 may not be the smallest possible such range. */
6114 vrp_meet (value_range_t *vr0, value_range_t *vr1)
6116 if (vr0->type == VR_UNDEFINED)
6118 copy_value_range (vr0, vr1);
6122 if (vr1->type == VR_UNDEFINED)
6124 /* Nothing to do. VR0 already has the resulting range. */
6128 if (vr0->type == VR_VARYING)
6130 /* Nothing to do. VR0 already has the resulting range. */
6134 if (vr1->type == VR_VARYING)
6136 set_value_range_to_varying (vr0);
6140 if (vr0->type == VR_RANGE && vr1->type == VR_RANGE)
6145 /* Compute the convex hull of the ranges. The lower limit of
6146 the new range is the minimum of the two ranges. If they
6147 cannot be compared, then give up. */
6148 cmp = compare_values (vr0->min, vr1->min);
6149 if (cmp == 0 || cmp == 1)
6156 /* Similarly, the upper limit of the new range is the maximum
6157 of the two ranges. If they cannot be compared, then
6159 cmp = compare_values (vr0->max, vr1->max);
6160 if (cmp == 0 || cmp == -1)
6167 /* Check for useless ranges. */
6168 if (INTEGRAL_TYPE_P (TREE_TYPE (min))
6169 && ((vrp_val_is_min (min) || is_overflow_infinity (min))
6170 && (vrp_val_is_max (max) || is_overflow_infinity (max))))
6173 /* The resulting set of equivalences is the intersection of
6175 if (vr0->equiv && vr1->equiv && vr0->equiv != vr1->equiv)
6176 bitmap_and_into (vr0->equiv, vr1->equiv);
6177 else if (vr0->equiv && !vr1->equiv)
6178 bitmap_clear (vr0->equiv);
6180 set_value_range (vr0, vr0->type, min, max, vr0->equiv);
6182 else if (vr0->type == VR_ANTI_RANGE && vr1->type == VR_ANTI_RANGE)
6184 /* Two anti-ranges meet only if their complements intersect.
6185 Only handle the case of identical ranges. */
6186 if (compare_values (vr0->min, vr1->min) == 0
6187 && compare_values (vr0->max, vr1->max) == 0
6188 && compare_values (vr0->min, vr0->max) == 0)
6190 /* The resulting set of equivalences is the intersection of
6192 if (vr0->equiv && vr1->equiv && vr0->equiv != vr1->equiv)
6193 bitmap_and_into (vr0->equiv, vr1->equiv);
6194 else if (vr0->equiv && !vr1->equiv)
6195 bitmap_clear (vr0->equiv);
6200 else if (vr0->type == VR_ANTI_RANGE || vr1->type == VR_ANTI_RANGE)
6202 /* For a numeric range [VAL1, VAL2] and an anti-range ~[VAL3, VAL4],
6203 only handle the case where the ranges have an empty intersection.
6204 The result of the meet operation is the anti-range. */
6205 if (!symbolic_range_p (vr0)
6206 && !symbolic_range_p (vr1)
6207 && !value_ranges_intersect_p (vr0, vr1))
6209 /* Copy most of VR1 into VR0. Don't copy VR1's equivalence
6210 set. We need to compute the intersection of the two
6211 equivalence sets. */
6212 if (vr1->type == VR_ANTI_RANGE)
6213 set_value_range (vr0, vr1->type, vr1->min, vr1->max, vr0->equiv);
6215 /* The resulting set of equivalences is the intersection of
6217 if (vr0->equiv && vr1->equiv && vr0->equiv != vr1->equiv)
6218 bitmap_and_into (vr0->equiv, vr1->equiv);
6219 else if (vr0->equiv && !vr1->equiv)
6220 bitmap_clear (vr0->equiv);
6231 /* Failed to find an efficient meet. Before giving up and setting
6232 the result to VARYING, see if we can at least derive a useful
6233 anti-range. FIXME, all this nonsense about distinguishing
6234 anti-ranges from ranges is necessary because of the odd
6235 semantics of range_includes_zero_p and friends. */
6236 if (!symbolic_range_p (vr0)
6237 && ((vr0->type == VR_RANGE && !range_includes_zero_p (vr0))
6238 || (vr0->type == VR_ANTI_RANGE && range_includes_zero_p (vr0)))
6239 && !symbolic_range_p (vr1)
6240 && ((vr1->type == VR_RANGE && !range_includes_zero_p (vr1))
6241 || (vr1->type == VR_ANTI_RANGE && range_includes_zero_p (vr1))))
6243 set_value_range_to_nonnull (vr0, TREE_TYPE (vr0->min));
6245 /* Since this meet operation did not result from the meeting of
6246 two equivalent names, VR0 cannot have any equivalences. */
6248 bitmap_clear (vr0->equiv);
6251 set_value_range_to_varying (vr0);
6255 /* Visit all arguments for PHI node PHI that flow through executable
6256 edges. If a valid value range can be derived from all the incoming
6257 value ranges, set a new range for the LHS of PHI. */
6259 static enum ssa_prop_result
6260 vrp_visit_phi_node (gimple phi)
6263 tree lhs = PHI_RESULT (phi);
6264 value_range_t *lhs_vr = get_value_range (lhs);
6265 value_range_t vr_result = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
6266 int edges, old_edges;
6268 copy_value_range (&vr_result, lhs_vr);
6270 if (dump_file && (dump_flags & TDF_DETAILS))
6272 fprintf (dump_file, "\nVisiting PHI node: ");
6273 print_gimple_stmt (dump_file, phi, 0, dump_flags);
6277 for (i = 0; i < gimple_phi_num_args (phi); i++)
6279 edge e = gimple_phi_arg_edge (phi, i);
6281 if (dump_file && (dump_flags & TDF_DETAILS))
6284 "\n Argument #%d (%d -> %d %sexecutable)\n",
6285 (int) i, e->src->index, e->dest->index,
6286 (e->flags & EDGE_EXECUTABLE) ? "" : "not ");
6289 if (e->flags & EDGE_EXECUTABLE)
6291 tree arg = PHI_ARG_DEF (phi, i);
6292 value_range_t vr_arg;
6296 if (TREE_CODE (arg) == SSA_NAME)
6298 vr_arg = *(get_value_range (arg));
6302 if (is_overflow_infinity (arg))
6304 arg = copy_node (arg);
6305 TREE_OVERFLOW (arg) = 0;
6308 vr_arg.type = VR_RANGE;
6311 vr_arg.equiv = NULL;
6314 if (dump_file && (dump_flags & TDF_DETAILS))
6316 fprintf (dump_file, "\t");
6317 print_generic_expr (dump_file, arg, dump_flags);
6318 fprintf (dump_file, "\n\tValue: ");
6319 dump_value_range (dump_file, &vr_arg);
6320 fprintf (dump_file, "\n");
6323 vrp_meet (&vr_result, &vr_arg);
6325 if (vr_result.type == VR_VARYING)
6330 if (vr_result.type == VR_VARYING)
6333 old_edges = vr_phi_edge_counts[SSA_NAME_VERSION (lhs)];
6334 vr_phi_edge_counts[SSA_NAME_VERSION (lhs)] = edges;
6336 /* To prevent infinite iterations in the algorithm, derive ranges
6337 when the new value is slightly bigger or smaller than the
6338 previous one. We don't do this if we have seen a new executable
6339 edge; this helps us avoid an overflow infinity for conditionals
6340 which are not in a loop. */
6341 if (lhs_vr->type == VR_RANGE && vr_result.type == VR_RANGE
6342 && edges <= old_edges)
6344 if (!POINTER_TYPE_P (TREE_TYPE (lhs)))
6346 int cmp_min = compare_values (lhs_vr->min, vr_result.min);
6347 int cmp_max = compare_values (lhs_vr->max, vr_result.max);
6349 /* If the new minimum is smaller or larger than the previous
6350 one, go all the way to -INF. In the first case, to avoid
6351 iterating millions of times to reach -INF, and in the
6352 other case to avoid infinite bouncing between different
6354 if (cmp_min > 0 || cmp_min < 0)
6356 /* If we will end up with a (-INF, +INF) range, set it to
6357 VARYING. Same if the previous max value was invalid for
6358 the type and we'd end up with vr_result.min > vr_result.max. */
6359 if (vrp_val_is_max (vr_result.max)
6360 || compare_values (TYPE_MIN_VALUE (TREE_TYPE (vr_result.min)),
6364 if (!needs_overflow_infinity (TREE_TYPE (vr_result.min))
6365 || !vrp_var_may_overflow (lhs, phi))
6366 vr_result.min = TYPE_MIN_VALUE (TREE_TYPE (vr_result.min));
6367 else if (supports_overflow_infinity (TREE_TYPE (vr_result.min)))
6369 negative_overflow_infinity (TREE_TYPE (vr_result.min));
6374 /* Similarly, if the new maximum is smaller or larger than
6375 the previous one, go all the way to +INF. */
6376 if (cmp_max < 0 || cmp_max > 0)
6378 /* If we will end up with a (-INF, +INF) range, set it to
6379 VARYING. Same if the previous min value was invalid for
6380 the type and we'd end up with vr_result.max < vr_result.min. */
6381 if (vrp_val_is_min (vr_result.min)
6382 || compare_values (TYPE_MAX_VALUE (TREE_TYPE (vr_result.max)),
6386 if (!needs_overflow_infinity (TREE_TYPE (vr_result.max))
6387 || !vrp_var_may_overflow (lhs, phi))
6388 vr_result.max = TYPE_MAX_VALUE (TREE_TYPE (vr_result.max));
6389 else if (supports_overflow_infinity (TREE_TYPE (vr_result.max)))
6391 positive_overflow_infinity (TREE_TYPE (vr_result.max));
6398 /* If the new range is different than the previous value, keep
6400 if (update_value_range (lhs, &vr_result))
6401 return SSA_PROP_INTERESTING;
6403 /* Nothing changed, don't add outgoing edges. */
6404 return SSA_PROP_NOT_INTERESTING;
6406 /* No match found. Set the LHS to VARYING. */
6408 set_value_range_to_varying (lhs_vr);
6409 return SSA_PROP_VARYING;
6412 /* Simplify boolean operations if the source is known
6413 to be already a boolean. */
6415 simplify_truth_ops_using_ranges (gimple_stmt_iterator *gsi, gimple stmt)
6417 enum tree_code rhs_code = gimple_assign_rhs_code (stmt);
6422 bool need_conversion;
6424 op0 = gimple_assign_rhs1 (stmt);
6425 if (TYPE_PRECISION (TREE_TYPE (op0)) != 1)
6427 if (TREE_CODE (op0) != SSA_NAME)
6429 vr = get_value_range (op0);
6431 val = compare_range_with_value (GE_EXPR, vr, integer_zero_node, &sop);
6432 if (!val || !integer_onep (val))
6435 val = compare_range_with_value (LE_EXPR, vr, integer_one_node, &sop);
6436 if (!val || !integer_onep (val))
6440 if (rhs_code == TRUTH_NOT_EXPR)
6443 op1 = build_int_cst (TREE_TYPE (op0), 1);
6447 op1 = gimple_assign_rhs2 (stmt);
6449 /* Reduce number of cases to handle. */
6450 if (is_gimple_min_invariant (op1))
6452 /* Exclude anything that should have been already folded. */
6453 if (rhs_code != EQ_EXPR
6454 && rhs_code != NE_EXPR
6455 && rhs_code != TRUTH_XOR_EXPR)
6458 if (!integer_zerop (op1)
6459 && !integer_onep (op1)
6460 && !integer_all_onesp (op1))
6463 /* Limit the number of cases we have to consider. */
6464 if (rhs_code == EQ_EXPR)
6467 op1 = fold_unary (TRUTH_NOT_EXPR, TREE_TYPE (op1), op1);
6472 /* Punt on A == B as there is no BIT_XNOR_EXPR. */
6473 if (rhs_code == EQ_EXPR)
6476 if (TYPE_PRECISION (TREE_TYPE (op1)) != 1)
6478 vr = get_value_range (op1);
6479 val = compare_range_with_value (GE_EXPR, vr, integer_zero_node, &sop);
6480 if (!val || !integer_onep (val))
6483 val = compare_range_with_value (LE_EXPR, vr, integer_one_node, &sop);
6484 if (!val || !integer_onep (val))
6490 if (sop && issue_strict_overflow_warning (WARN_STRICT_OVERFLOW_MISC))
6492 location_t location;
6494 if (!gimple_has_location (stmt))
6495 location = input_location;
6497 location = gimple_location (stmt);
6499 if (rhs_code == TRUTH_AND_EXPR || rhs_code == TRUTH_OR_EXPR)
6500 warning_at (location, OPT_Wstrict_overflow,
6501 _("assuming signed overflow does not occur when "
6502 "simplifying && or || to & or |"));
6504 warning_at (location, OPT_Wstrict_overflow,
6505 _("assuming signed overflow does not occur when "
6506 "simplifying ==, != or ! to identity or ^"));
6510 !useless_type_conversion_p (TREE_TYPE (gimple_assign_lhs (stmt)),
6513 /* Make sure to not sign-extend -1 as a boolean value. */
6515 && !TYPE_UNSIGNED (TREE_TYPE (op0))
6516 && TYPE_PRECISION (TREE_TYPE (op0)) == 1)
6521 case TRUTH_AND_EXPR:
6522 rhs_code = BIT_AND_EXPR;
6525 rhs_code = BIT_IOR_EXPR;
6527 case TRUTH_XOR_EXPR:
6529 if (integer_zerop (op1))
6531 gimple_assign_set_rhs_with_ops (gsi,
6532 need_conversion ? NOP_EXPR : SSA_NAME,
6534 update_stmt (gsi_stmt (*gsi));
6538 rhs_code = BIT_XOR_EXPR;
6544 if (need_conversion)
6547 gimple_assign_set_rhs_with_ops (gsi, rhs_code, op0, op1);
6548 update_stmt (gsi_stmt (*gsi));
6552 /* Simplify a division or modulo operator to a right shift or
6553 bitwise and if the first operand is unsigned or is greater
6554 than zero and the second operand is an exact power of two. */
6557 simplify_div_or_mod_using_ranges (gimple stmt)
6559 enum tree_code rhs_code = gimple_assign_rhs_code (stmt);
6561 tree op0 = gimple_assign_rhs1 (stmt);
6562 tree op1 = gimple_assign_rhs2 (stmt);
6563 value_range_t *vr = get_value_range (gimple_assign_rhs1 (stmt));
6565 if (TYPE_UNSIGNED (TREE_TYPE (op0)))
6567 val = integer_one_node;
6573 val = compare_range_with_value (GE_EXPR, vr, integer_zero_node, &sop);
6577 && integer_onep (val)
6578 && issue_strict_overflow_warning (WARN_STRICT_OVERFLOW_MISC))
6580 location_t location;
6582 if (!gimple_has_location (stmt))
6583 location = input_location;
6585 location = gimple_location (stmt);
6586 warning (OPT_Wstrict_overflow,
6587 ("%Hassuming signed overflow does not occur when "
6588 "simplifying / or %% to >> or &"),
6593 if (val && integer_onep (val))
6597 if (rhs_code == TRUNC_DIV_EXPR)
6599 t = build_int_cst (NULL_TREE, tree_log2 (op1));
6600 gimple_assign_set_rhs_code (stmt, RSHIFT_EXPR);
6601 gimple_assign_set_rhs1 (stmt, op0);
6602 gimple_assign_set_rhs2 (stmt, t);
6606 t = build_int_cst (TREE_TYPE (op1), 1);
6607 t = int_const_binop (MINUS_EXPR, op1, t, 0);
6608 t = fold_convert (TREE_TYPE (op0), t);
6610 gimple_assign_set_rhs_code (stmt, BIT_AND_EXPR);
6611 gimple_assign_set_rhs1 (stmt, op0);
6612 gimple_assign_set_rhs2 (stmt, t);
6622 /* If the operand to an ABS_EXPR is >= 0, then eliminate the
6623 ABS_EXPR. If the operand is <= 0, then simplify the
6624 ABS_EXPR into a NEGATE_EXPR. */
6627 simplify_abs_using_ranges (gimple stmt)
6630 tree op = gimple_assign_rhs1 (stmt);
6631 tree type = TREE_TYPE (op);
6632 value_range_t *vr = get_value_range (op);
6634 if (TYPE_UNSIGNED (type))
6636 val = integer_zero_node;
6642 val = compare_range_with_value (LE_EXPR, vr, integer_zero_node, &sop);
6646 val = compare_range_with_value (GE_EXPR, vr, integer_zero_node,
6651 if (integer_zerop (val))
6652 val = integer_one_node;
6653 else if (integer_onep (val))
6654 val = integer_zero_node;
6659 && (integer_onep (val) || integer_zerop (val)))
6661 if (sop && issue_strict_overflow_warning (WARN_STRICT_OVERFLOW_MISC))
6663 location_t location;
6665 if (!gimple_has_location (stmt))
6666 location = input_location;
6668 location = gimple_location (stmt);
6669 warning (OPT_Wstrict_overflow,
6670 ("%Hassuming signed overflow does not occur when "
6671 "simplifying abs (X) to X or -X"),
6675 gimple_assign_set_rhs1 (stmt, op);
6676 if (integer_onep (val))
6677 gimple_assign_set_rhs_code (stmt, NEGATE_EXPR);
6679 gimple_assign_set_rhs_code (stmt, SSA_NAME);
6688 /* We are comparing trees OP0 and OP1 using COND_CODE. OP0 has
6689 a known value range VR.
6691 If there is one and only one value which will satisfy the
6692 conditional, then return that value. Else return NULL. */
6695 test_for_singularity (enum tree_code cond_code, tree op0,
6696 tree op1, value_range_t *vr)
6701 /* Extract minimum/maximum values which satisfy the
6702 the conditional as it was written. */
6703 if (cond_code == LE_EXPR || cond_code == LT_EXPR)
6705 /* This should not be negative infinity; there is no overflow
6707 min = TYPE_MIN_VALUE (TREE_TYPE (op0));
6710 if (cond_code == LT_EXPR && !is_overflow_infinity (max))
6712 tree one = build_int_cst (TREE_TYPE (op0), 1);
6713 max = fold_build2 (MINUS_EXPR, TREE_TYPE (op0), max, one);
6715 TREE_NO_WARNING (max) = 1;
6718 else if (cond_code == GE_EXPR || cond_code == GT_EXPR)
6720 /* This should not be positive infinity; there is no overflow
6722 max = TYPE_MAX_VALUE (TREE_TYPE (op0));
6725 if (cond_code == GT_EXPR && !is_overflow_infinity (min))
6727 tree one = build_int_cst (TREE_TYPE (op0), 1);
6728 min = fold_build2 (PLUS_EXPR, TREE_TYPE (op0), min, one);
6730 TREE_NO_WARNING (min) = 1;
6734 /* Now refine the minimum and maximum values using any
6735 value range information we have for op0. */
6738 if (compare_values (vr->min, min) == -1)
6742 if (compare_values (vr->max, max) == 1)
6747 /* If the new min/max values have converged to a single value,
6748 then there is only one value which can satisfy the condition,
6749 return that value. */
6750 if (operand_equal_p (min, max, 0) && is_gimple_min_invariant (min))
6756 /* Simplify a conditional using a relational operator to an equality
6757 test if the range information indicates only one value can satisfy
6758 the original conditional. */
6761 simplify_cond_using_ranges (gimple stmt)
6763 tree op0 = gimple_cond_lhs (stmt);
6764 tree op1 = gimple_cond_rhs (stmt);
6765 enum tree_code cond_code = gimple_cond_code (stmt);
6767 if (cond_code != NE_EXPR
6768 && cond_code != EQ_EXPR
6769 && TREE_CODE (op0) == SSA_NAME
6770 && INTEGRAL_TYPE_P (TREE_TYPE (op0))
6771 && is_gimple_min_invariant (op1))
6773 value_range_t *vr = get_value_range (op0);
6775 /* If we have range information for OP0, then we might be
6776 able to simplify this conditional. */
6777 if (vr->type == VR_RANGE)
6779 tree new_tree = test_for_singularity (cond_code, op0, op1, vr);
6785 fprintf (dump_file, "Simplified relational ");
6786 print_gimple_stmt (dump_file, stmt, 0, 0);
6787 fprintf (dump_file, " into ");
6790 gimple_cond_set_code (stmt, EQ_EXPR);
6791 gimple_cond_set_lhs (stmt, op0);
6792 gimple_cond_set_rhs (stmt, new_tree);
6798 print_gimple_stmt (dump_file, stmt, 0, 0);
6799 fprintf (dump_file, "\n");
6805 /* Try again after inverting the condition. We only deal
6806 with integral types here, so no need to worry about
6807 issues with inverting FP comparisons. */
6808 cond_code = invert_tree_comparison (cond_code, false);
6809 new_tree = test_for_singularity (cond_code, op0, op1, vr);
6815 fprintf (dump_file, "Simplified relational ");
6816 print_gimple_stmt (dump_file, stmt, 0, 0);
6817 fprintf (dump_file, " into ");
6820 gimple_cond_set_code (stmt, NE_EXPR);
6821 gimple_cond_set_lhs (stmt, op0);
6822 gimple_cond_set_rhs (stmt, new_tree);
6828 print_gimple_stmt (dump_file, stmt, 0, 0);
6829 fprintf (dump_file, "\n");
6840 /* Simplify a switch statement using the value range of the switch
6844 simplify_switch_using_ranges (gimple stmt)
6846 tree op = gimple_switch_index (stmt);
6851 size_t i = 0, j = 0, n, n2;
6855 if (TREE_CODE (op) == SSA_NAME)
6857 vr = get_value_range (op);
6859 /* We can only handle integer ranges. */
6860 if (vr->type != VR_RANGE
6861 || symbolic_range_p (vr))
6864 /* Find case label for min/max of the value range. */
6865 take_default = !find_case_label_range (stmt, vr->min, vr->max, &i, &j);
6867 else if (TREE_CODE (op) == INTEGER_CST)
6869 take_default = !find_case_label_index (stmt, 1, op, &i);
6883 n = gimple_switch_num_labels (stmt);
6885 /* Bail out if this is just all edges taken. */
6891 /* Build a new vector of taken case labels. */
6892 vec2 = make_tree_vec (j - i + 1 + (int)take_default);
6895 /* Add the default edge, if necessary. */
6897 TREE_VEC_ELT (vec2, n2++) = gimple_switch_default_label (stmt);
6899 for (; i <= j; ++i, ++n2)
6900 TREE_VEC_ELT (vec2, n2) = gimple_switch_label (stmt, i);
6902 /* Mark needed edges. */
6903 for (i = 0; i < n2; ++i)
6905 e = find_edge (gimple_bb (stmt),
6906 label_to_block (CASE_LABEL (TREE_VEC_ELT (vec2, i))));
6907 e->aux = (void *)-1;
6910 /* Queue not needed edges for later removal. */
6911 FOR_EACH_EDGE (e, ei, gimple_bb (stmt)->succs)
6913 if (e->aux == (void *)-1)
6919 if (dump_file && (dump_flags & TDF_DETAILS))
6921 fprintf (dump_file, "removing unreachable case label\n");
6923 VEC_safe_push (edge, heap, to_remove_edges, e);
6926 /* And queue an update for the stmt. */
6929 VEC_safe_push (switch_update, heap, to_update_switch_stmts, &su);
6933 /* Simplify STMT using ranges if possible. */
6936 simplify_stmt_using_ranges (gimple_stmt_iterator *gsi)
6938 gimple stmt = gsi_stmt (*gsi);
6939 if (is_gimple_assign (stmt))
6941 enum tree_code rhs_code = gimple_assign_rhs_code (stmt);
6947 case TRUTH_NOT_EXPR:
6948 case TRUTH_AND_EXPR:
6950 case TRUTH_XOR_EXPR:
6951 /* Transform EQ_EXPR, NE_EXPR, TRUTH_NOT_EXPR into BIT_XOR_EXPR
6952 or identity if the RHS is zero or one, and the LHS are known
6953 to be boolean values. Transform all TRUTH_*_EXPR into
6954 BIT_*_EXPR if both arguments are known to be boolean values. */
6955 if (INTEGRAL_TYPE_P (TREE_TYPE (gimple_assign_rhs1 (stmt))))
6956 return simplify_truth_ops_using_ranges (gsi, stmt);
6959 /* Transform TRUNC_DIV_EXPR and TRUNC_MOD_EXPR into RSHIFT_EXPR
6960 and BIT_AND_EXPR respectively if the first operand is greater
6961 than zero and the second operand is an exact power of two. */
6962 case TRUNC_DIV_EXPR:
6963 case TRUNC_MOD_EXPR:
6964 if (INTEGRAL_TYPE_P (TREE_TYPE (gimple_assign_rhs1 (stmt)))
6965 && integer_pow2p (gimple_assign_rhs2 (stmt)))
6966 return simplify_div_or_mod_using_ranges (stmt);
6969 /* Transform ABS (X) into X or -X as appropriate. */
6971 if (TREE_CODE (gimple_assign_rhs1 (stmt)) == SSA_NAME
6972 && INTEGRAL_TYPE_P (TREE_TYPE (gimple_assign_rhs1 (stmt))))
6973 return simplify_abs_using_ranges (stmt);
6980 else if (gimple_code (stmt) == GIMPLE_COND)
6981 return simplify_cond_using_ranges (stmt);
6982 else if (gimple_code (stmt) == GIMPLE_SWITCH)
6983 return simplify_switch_using_ranges (stmt);
6988 /* Stack of dest,src equivalency pairs that need to be restored after
6989 each attempt to thread a block's incoming edge to an outgoing edge.
6991 A NULL entry is used to mark the end of pairs which need to be
6993 static VEC(tree,heap) *stack;
6995 /* A trivial wrapper so that we can present the generic jump threading
6996 code with a simple API for simplifying statements. STMT is the
6997 statement we want to simplify, WITHIN_STMT provides the location
6998 for any overflow warnings. */
7001 simplify_stmt_for_jump_threading (gimple stmt, gimple within_stmt)
7003 /* We only use VRP information to simplify conditionals. This is
7004 overly conservative, but it's unclear if doing more would be
7005 worth the compile time cost. */
7006 if (gimple_code (stmt) != GIMPLE_COND)
7009 return vrp_evaluate_conditional (gimple_cond_code (stmt),
7010 gimple_cond_lhs (stmt),
7011 gimple_cond_rhs (stmt), within_stmt);
7014 /* Blocks which have more than one predecessor and more than
7015 one successor present jump threading opportunities, i.e.,
7016 when the block is reached from a specific predecessor, we
7017 may be able to determine which of the outgoing edges will
7018 be traversed. When this optimization applies, we are able
7019 to avoid conditionals at runtime and we may expose secondary
7020 optimization opportunities.
7022 This routine is effectively a driver for the generic jump
7023 threading code. It basically just presents the generic code
7024 with edges that may be suitable for jump threading.
7026 Unlike DOM, we do not iterate VRP if jump threading was successful.
7027 While iterating may expose new opportunities for VRP, it is expected
7028 those opportunities would be very limited and the compile time cost
7029 to expose those opportunities would be significant.
7031 As jump threading opportunities are discovered, they are registered
7032 for later realization. */
7035 identify_jump_threads (void)
7042 /* Ugh. When substituting values earlier in this pass we can
7043 wipe the dominance information. So rebuild the dominator
7044 information as we need it within the jump threading code. */
7045 calculate_dominance_info (CDI_DOMINATORS);
7047 /* We do not allow VRP information to be used for jump threading
7048 across a back edge in the CFG. Otherwise it becomes too
7049 difficult to avoid eliminating loop exit tests. Of course
7050 EDGE_DFS_BACK is not accurate at this time so we have to
7052 mark_dfs_back_edges ();
7054 /* Do not thread across edges we are about to remove. Just marking
7055 them as EDGE_DFS_BACK will do. */
7056 for (i = 0; VEC_iterate (edge, to_remove_edges, i, e); ++i)
7057 e->flags |= EDGE_DFS_BACK;
7059 /* Allocate our unwinder stack to unwind any temporary equivalences
7060 that might be recorded. */
7061 stack = VEC_alloc (tree, heap, 20);
7063 /* To avoid lots of silly node creation, we create a single
7064 conditional and just modify it in-place when attempting to
7066 dummy = gimple_build_cond (EQ_EXPR,
7067 integer_zero_node, integer_zero_node,
7070 /* Walk through all the blocks finding those which present a
7071 potential jump threading opportunity. We could set this up
7072 as a dominator walker and record data during the walk, but
7073 I doubt it's worth the effort for the classes of jump
7074 threading opportunities we are trying to identify at this
7075 point in compilation. */
7080 /* If the generic jump threading code does not find this block
7081 interesting, then there is nothing to do. */
7082 if (! potentially_threadable_block (bb))
7085 /* We only care about blocks ending in a COND_EXPR. While there
7086 may be some value in handling SWITCH_EXPR here, I doubt it's
7087 terribly important. */
7088 last = gsi_stmt (gsi_last_bb (bb));
7089 if (gimple_code (last) != GIMPLE_COND)
7092 /* We're basically looking for any kind of conditional with
7093 integral type arguments. */
7094 if (TREE_CODE (gimple_cond_lhs (last)) == SSA_NAME
7095 && INTEGRAL_TYPE_P (TREE_TYPE (gimple_cond_lhs (last)))
7096 && (TREE_CODE (gimple_cond_rhs (last)) == SSA_NAME
7097 || is_gimple_min_invariant (gimple_cond_rhs (last)))
7098 && INTEGRAL_TYPE_P (TREE_TYPE (gimple_cond_rhs (last))))
7102 /* We've got a block with multiple predecessors and multiple
7103 successors which also ends in a suitable conditional. For
7104 each predecessor, see if we can thread it to a specific
7106 FOR_EACH_EDGE (e, ei, bb->preds)
7108 /* Do not thread across back edges or abnormal edges
7110 if (e->flags & (EDGE_DFS_BACK | EDGE_COMPLEX))
7113 thread_across_edge (dummy, e, true, &stack,
7114 simplify_stmt_for_jump_threading);
7119 /* We do not actually update the CFG or SSA graphs at this point as
7120 ASSERT_EXPRs are still in the IL and cfg cleanup code does not yet
7121 handle ASSERT_EXPRs gracefully. */
7124 /* We identified all the jump threading opportunities earlier, but could
7125 not transform the CFG at that time. This routine transforms the
7126 CFG and arranges for the dominator tree to be rebuilt if necessary.
7128 Note the SSA graph update will occur during the normal TODO
7129 processing by the pass manager. */
7131 finalize_jump_threads (void)
7133 thread_through_all_blocks (false);
7134 VEC_free (tree, heap, stack);
7138 /* Traverse all the blocks folding conditionals with known ranges. */
7144 prop_value_t *single_val_range;
7145 bool do_value_subst_p;
7149 fprintf (dump_file, "\nValue ranges after VRP:\n\n");
7150 dump_all_value_ranges (dump_file);
7151 fprintf (dump_file, "\n");
7154 /* We may have ended with ranges that have exactly one value. Those
7155 values can be substituted as any other copy/const propagated
7156 value using substitute_and_fold. */
7157 single_val_range = XCNEWVEC (prop_value_t, num_ssa_names);
7159 do_value_subst_p = false;
7160 for (i = 0; i < num_ssa_names; i++)
7162 && vr_value[i]->type == VR_RANGE
7163 && vr_value[i]->min == vr_value[i]->max)
7165 single_val_range[i].value = vr_value[i]->min;
7166 do_value_subst_p = true;
7169 if (!do_value_subst_p)
7171 /* We found no single-valued ranges, don't waste time trying to
7172 do single value substitution in substitute_and_fold. */
7173 free (single_val_range);
7174 single_val_range = NULL;
7177 substitute_and_fold (single_val_range, true);
7179 if (warn_array_bounds)
7180 check_all_array_refs ();
7182 /* We must identify jump threading opportunities before we release
7183 the datastructures built by VRP. */
7184 identify_jump_threads ();
7186 /* Free allocated memory. */
7187 for (i = 0; i < num_ssa_names; i++)
7190 BITMAP_FREE (vr_value[i]->equiv);
7194 free (single_val_range);
7196 free (vr_phi_edge_counts);
7198 /* So that we can distinguish between VRP data being available
7199 and not available. */
7201 vr_phi_edge_counts = NULL;
7205 /* Main entry point to VRP (Value Range Propagation). This pass is
7206 loosely based on J. R. C. Patterson, ``Accurate Static Branch
7207 Prediction by Value Range Propagation,'' in SIGPLAN Conference on
7208 Programming Language Design and Implementation, pp. 67-78, 1995.
7209 Also available at http://citeseer.ist.psu.edu/patterson95accurate.html
7211 This is essentially an SSA-CCP pass modified to deal with ranges
7212 instead of constants.
7214 While propagating ranges, we may find that two or more SSA name
7215 have equivalent, though distinct ranges. For instance,
7218 2 p_4 = ASSERT_EXPR <p_3, p_3 != 0>
7220 4 p_5 = ASSERT_EXPR <p_4, p_4 == q_2>;
7224 In the code above, pointer p_5 has range [q_2, q_2], but from the
7225 code we can also determine that p_5 cannot be NULL and, if q_2 had
7226 a non-varying range, p_5's range should also be compatible with it.
7228 These equivalences are created by two expressions: ASSERT_EXPR and
7229 copy operations. Since p_5 is an assertion on p_4, and p_4 was the
7230 result of another assertion, then we can use the fact that p_5 and
7231 p_4 are equivalent when evaluating p_5's range.
7233 Together with value ranges, we also propagate these equivalences
7234 between names so that we can take advantage of information from
7235 multiple ranges when doing final replacement. Note that this
7236 equivalency relation is transitive but not symmetric.
7238 In the example above, p_5 is equivalent to p_4, q_2 and p_3, but we
7239 cannot assert that q_2 is equivalent to p_5 because q_2 may be used
7240 in contexts where that assertion does not hold (e.g., in line 6).
7242 TODO, the main difference between this pass and Patterson's is that
7243 we do not propagate edge probabilities. We only compute whether
7244 edges can be taken or not. That is, instead of having a spectrum
7245 of jump probabilities between 0 and 1, we only deal with 0, 1 and
7246 DON'T KNOW. In the future, it may be worthwhile to propagate
7247 probabilities to aid branch prediction. */
7256 loop_optimizer_init (LOOPS_NORMAL | LOOPS_HAVE_RECORDED_EXITS);
7257 rewrite_into_loop_closed_ssa (NULL, TODO_update_ssa);
7260 insert_range_assertions ();
7262 to_remove_edges = VEC_alloc (edge, heap, 10);
7263 to_update_switch_stmts = VEC_alloc (switch_update, heap, 5);
7266 ssa_propagate (vrp_visit_stmt, vrp_visit_phi_node);
7269 /* ASSERT_EXPRs must be removed before finalizing jump threads
7270 as finalizing jump threads calls the CFG cleanup code which
7271 does not properly handle ASSERT_EXPRs. */
7272 remove_range_assertions ();
7274 /* If we exposed any new variables, go ahead and put them into
7275 SSA form now, before we handle jump threading. This simplifies
7276 interactions between rewriting of _DECL nodes into SSA form
7277 and rewriting SSA_NAME nodes into SSA form after block
7278 duplication and CFG manipulation. */
7279 update_ssa (TODO_update_ssa);
7281 finalize_jump_threads ();
7283 /* Remove dead edges from SWITCH_EXPR optimization. This leaves the
7284 CFG in a broken state and requires a cfg_cleanup run. */
7285 for (i = 0; VEC_iterate (edge, to_remove_edges, i, e); ++i)
7287 /* Update SWITCH_EXPR case label vector. */
7288 for (i = 0; VEC_iterate (switch_update, to_update_switch_stmts, i, su); ++i)
7291 size_t n = TREE_VEC_LENGTH (su->vec);
7293 gimple_switch_set_num_labels (su->stmt, n);
7294 for (j = 0; j < n; j++)
7295 gimple_switch_set_label (su->stmt, j, TREE_VEC_ELT (su->vec, j));
7296 /* As we may have replaced the default label with a regular one
7297 make sure to make it a real default label again. This ensures
7298 optimal expansion. */
7299 label = gimple_switch_default_label (su->stmt);
7300 CASE_LOW (label) = NULL_TREE;
7301 CASE_HIGH (label) = NULL_TREE;
7304 if (VEC_length (edge, to_remove_edges) > 0)
7305 free_dominance_info (CDI_DOMINATORS);
7307 VEC_free (edge, heap, to_remove_edges);
7308 VEC_free (switch_update, heap, to_update_switch_stmts);
7311 loop_optimizer_finalize ();
7318 return flag_tree_vrp != 0;
7321 struct gimple_opt_pass pass_vrp =
7326 gate_vrp, /* gate */
7327 execute_vrp, /* execute */
7330 0, /* static_pass_number */
7331 TV_TREE_VRP, /* tv_id */
7332 PROP_ssa | PROP_alias, /* properties_required */
7333 0, /* properties_provided */
7334 0, /* properties_destroyed */
7335 0, /* todo_flags_start */
7340 | TODO_update_ssa /* todo_flags_finish */