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 /* Return true if T, an SSA_NAME, is known to be nonzero. Return
1372 false otherwise or if no value range information is available. */
1375 ssa_name_nonzero_p (const_tree t)
1377 value_range_t *vr = get_value_range (t);
1382 /* A VR_RANGE which does not include zero is a nonzero value. */
1383 if (vr->type == VR_RANGE && !symbolic_range_p (vr))
1384 return ! range_includes_zero_p (vr);
1386 /* A VR_ANTI_RANGE which does include zero is a nonzero value. */
1387 if (vr->type == VR_ANTI_RANGE && !symbolic_range_p (vr))
1388 return range_includes_zero_p (vr);
1393 /* If OP has a value range with a single constant value return that,
1394 otherwise return NULL_TREE. This returns OP itself if OP is a
1398 op_with_constant_singleton_value_range (tree op)
1402 if (is_gimple_min_invariant (op))
1405 if (TREE_CODE (op) != SSA_NAME)
1408 vr = get_value_range (op);
1409 if (vr->type == VR_RANGE
1410 && operand_equal_p (vr->min, vr->max, 0)
1411 && is_gimple_min_invariant (vr->min))
1418 /* Extract value range information from an ASSERT_EXPR EXPR and store
1422 extract_range_from_assert (value_range_t *vr_p, tree expr)
1424 tree var, cond, limit, min, max, type;
1425 value_range_t *var_vr, *limit_vr;
1426 enum tree_code cond_code;
1428 var = ASSERT_EXPR_VAR (expr);
1429 cond = ASSERT_EXPR_COND (expr);
1431 gcc_assert (COMPARISON_CLASS_P (cond));
1433 /* Find VAR in the ASSERT_EXPR conditional. */
1434 if (var == TREE_OPERAND (cond, 0)
1435 || TREE_CODE (TREE_OPERAND (cond, 0)) == PLUS_EXPR
1436 || TREE_CODE (TREE_OPERAND (cond, 0)) == NOP_EXPR)
1438 /* If the predicate is of the form VAR COMP LIMIT, then we just
1439 take LIMIT from the RHS and use the same comparison code. */
1440 cond_code = TREE_CODE (cond);
1441 limit = TREE_OPERAND (cond, 1);
1442 cond = TREE_OPERAND (cond, 0);
1446 /* If the predicate is of the form LIMIT COMP VAR, then we need
1447 to flip around the comparison code to create the proper range
1449 cond_code = swap_tree_comparison (TREE_CODE (cond));
1450 limit = TREE_OPERAND (cond, 0);
1451 cond = TREE_OPERAND (cond, 1);
1454 limit = avoid_overflow_infinity (limit);
1456 type = TREE_TYPE (limit);
1457 gcc_assert (limit != var);
1459 /* For pointer arithmetic, we only keep track of pointer equality
1461 if (POINTER_TYPE_P (type) && cond_code != NE_EXPR && cond_code != EQ_EXPR)
1463 set_value_range_to_varying (vr_p);
1467 /* If LIMIT is another SSA name and LIMIT has a range of its own,
1468 try to use LIMIT's range to avoid creating symbolic ranges
1470 limit_vr = (TREE_CODE (limit) == SSA_NAME) ? get_value_range (limit) : NULL;
1472 /* LIMIT's range is only interesting if it has any useful information. */
1474 && (limit_vr->type == VR_UNDEFINED
1475 || limit_vr->type == VR_VARYING
1476 || symbolic_range_p (limit_vr)))
1479 /* Initially, the new range has the same set of equivalences of
1480 VAR's range. This will be revised before returning the final
1481 value. Since assertions may be chained via mutually exclusive
1482 predicates, we will need to trim the set of equivalences before
1484 gcc_assert (vr_p->equiv == NULL);
1485 add_equivalence (&vr_p->equiv, var);
1487 /* Extract a new range based on the asserted comparison for VAR and
1488 LIMIT's value range. Notice that if LIMIT has an anti-range, we
1489 will only use it for equality comparisons (EQ_EXPR). For any
1490 other kind of assertion, we cannot derive a range from LIMIT's
1491 anti-range that can be used to describe the new range. For
1492 instance, ASSERT_EXPR <x_2, x_2 <= b_4>. If b_4 is ~[2, 10],
1493 then b_4 takes on the ranges [-INF, 1] and [11, +INF]. There is
1494 no single range for x_2 that could describe LE_EXPR, so we might
1495 as well build the range [b_4, +INF] for it.
1496 One special case we handle is extracting a range from a
1497 range test encoded as (unsigned)var + CST <= limit. */
1498 if (TREE_CODE (cond) == NOP_EXPR
1499 || TREE_CODE (cond) == PLUS_EXPR)
1501 if (TREE_CODE (cond) == PLUS_EXPR)
1503 min = fold_build1 (NEGATE_EXPR, TREE_TYPE (TREE_OPERAND (cond, 1)),
1504 TREE_OPERAND (cond, 1));
1505 max = int_const_binop (PLUS_EXPR, limit, min, 0);
1506 cond = TREE_OPERAND (cond, 0);
1510 min = build_int_cst (TREE_TYPE (var), 0);
1514 /* Make sure to not set TREE_OVERFLOW on the final type
1515 conversion. We are willingly interpreting large positive
1516 unsigned values as negative singed values here. */
1517 min = force_fit_type_double (TREE_TYPE (var), TREE_INT_CST_LOW (min),
1518 TREE_INT_CST_HIGH (min), 0, false);
1519 max = force_fit_type_double (TREE_TYPE (var), TREE_INT_CST_LOW (max),
1520 TREE_INT_CST_HIGH (max), 0, false);
1522 /* We can transform a max, min range to an anti-range or
1523 vice-versa. Use set_and_canonicalize_value_range which does
1525 if (cond_code == LE_EXPR)
1526 set_and_canonicalize_value_range (vr_p, VR_RANGE,
1527 min, max, vr_p->equiv);
1528 else if (cond_code == GT_EXPR)
1529 set_and_canonicalize_value_range (vr_p, VR_ANTI_RANGE,
1530 min, max, vr_p->equiv);
1534 else if (cond_code == EQ_EXPR)
1536 enum value_range_type range_type;
1540 range_type = limit_vr->type;
1541 min = limit_vr->min;
1542 max = limit_vr->max;
1546 range_type = VR_RANGE;
1551 set_value_range (vr_p, range_type, min, max, vr_p->equiv);
1553 /* When asserting the equality VAR == LIMIT and LIMIT is another
1554 SSA name, the new range will also inherit the equivalence set
1556 if (TREE_CODE (limit) == SSA_NAME)
1557 add_equivalence (&vr_p->equiv, limit);
1559 else if (cond_code == NE_EXPR)
1561 /* As described above, when LIMIT's range is an anti-range and
1562 this assertion is an inequality (NE_EXPR), then we cannot
1563 derive anything from the anti-range. For instance, if
1564 LIMIT's range was ~[0, 0], the assertion 'VAR != LIMIT' does
1565 not imply that VAR's range is [0, 0]. So, in the case of
1566 anti-ranges, we just assert the inequality using LIMIT and
1569 If LIMIT_VR is a range, we can only use it to build a new
1570 anti-range if LIMIT_VR is a single-valued range. For
1571 instance, if LIMIT_VR is [0, 1], the predicate
1572 VAR != [0, 1] does not mean that VAR's range is ~[0, 1].
1573 Rather, it means that for value 0 VAR should be ~[0, 0]
1574 and for value 1, VAR should be ~[1, 1]. We cannot
1575 represent these ranges.
1577 The only situation in which we can build a valid
1578 anti-range is when LIMIT_VR is a single-valued range
1579 (i.e., LIMIT_VR->MIN == LIMIT_VR->MAX). In that case,
1580 build the anti-range ~[LIMIT_VR->MIN, LIMIT_VR->MAX]. */
1582 && limit_vr->type == VR_RANGE
1583 && compare_values (limit_vr->min, limit_vr->max) == 0)
1585 min = limit_vr->min;
1586 max = limit_vr->max;
1590 /* In any other case, we cannot use LIMIT's range to build a
1591 valid anti-range. */
1595 /* If MIN and MAX cover the whole range for their type, then
1596 just use the original LIMIT. */
1597 if (INTEGRAL_TYPE_P (type)
1598 && vrp_val_is_min (min)
1599 && vrp_val_is_max (max))
1602 set_value_range (vr_p, VR_ANTI_RANGE, min, max, vr_p->equiv);
1604 else if (cond_code == LE_EXPR || cond_code == LT_EXPR)
1606 min = TYPE_MIN_VALUE (type);
1608 if (limit_vr == NULL || limit_vr->type == VR_ANTI_RANGE)
1612 /* If LIMIT_VR is of the form [N1, N2], we need to build the
1613 range [MIN, N2] for LE_EXPR and [MIN, N2 - 1] for
1615 max = limit_vr->max;
1618 /* If the maximum value forces us to be out of bounds, simply punt.
1619 It would be pointless to try and do anything more since this
1620 all should be optimized away above us. */
1621 if ((cond_code == LT_EXPR
1622 && compare_values (max, min) == 0)
1623 || (CONSTANT_CLASS_P (max) && TREE_OVERFLOW (max)))
1624 set_value_range_to_varying (vr_p);
1627 /* For LT_EXPR, we create the range [MIN, MAX - 1]. */
1628 if (cond_code == LT_EXPR)
1630 tree one = build_int_cst (type, 1);
1631 max = fold_build2 (MINUS_EXPR, type, max, one);
1633 TREE_NO_WARNING (max) = 1;
1636 set_value_range (vr_p, VR_RANGE, min, max, vr_p->equiv);
1639 else if (cond_code == GE_EXPR || cond_code == GT_EXPR)
1641 max = TYPE_MAX_VALUE (type);
1643 if (limit_vr == NULL || limit_vr->type == VR_ANTI_RANGE)
1647 /* If LIMIT_VR is of the form [N1, N2], we need to build the
1648 range [N1, MAX] for GE_EXPR and [N1 + 1, MAX] for
1650 min = limit_vr->min;
1653 /* If the minimum value forces us to be out of bounds, simply punt.
1654 It would be pointless to try and do anything more since this
1655 all should be optimized away above us. */
1656 if ((cond_code == GT_EXPR
1657 && compare_values (min, max) == 0)
1658 || (CONSTANT_CLASS_P (min) && TREE_OVERFLOW (min)))
1659 set_value_range_to_varying (vr_p);
1662 /* For GT_EXPR, we create the range [MIN + 1, MAX]. */
1663 if (cond_code == GT_EXPR)
1665 tree one = build_int_cst (type, 1);
1666 min = fold_build2 (PLUS_EXPR, type, min, one);
1668 TREE_NO_WARNING (min) = 1;
1671 set_value_range (vr_p, VR_RANGE, min, max, vr_p->equiv);
1677 /* If VAR already had a known range, it may happen that the new
1678 range we have computed and VAR's range are not compatible. For
1682 p_6 = ASSERT_EXPR <p_5, p_5 == NULL>;
1684 p_8 = ASSERT_EXPR <p_6, p_6 != NULL>;
1686 While the above comes from a faulty program, it will cause an ICE
1687 later because p_8 and p_6 will have incompatible ranges and at
1688 the same time will be considered equivalent. A similar situation
1692 i_6 = ASSERT_EXPR <i_5, i_5 > 10>;
1694 i_7 = ASSERT_EXPR <i_6, i_6 < 5>;
1696 Again i_6 and i_7 will have incompatible ranges. It would be
1697 pointless to try and do anything with i_7's range because
1698 anything dominated by 'if (i_5 < 5)' will be optimized away.
1699 Note, due to the wa in which simulation proceeds, the statement
1700 i_7 = ASSERT_EXPR <...> we would never be visited because the
1701 conditional 'if (i_5 < 5)' always evaluates to false. However,
1702 this extra check does not hurt and may protect against future
1703 changes to VRP that may get into a situation similar to the
1704 NULL pointer dereference example.
1706 Note that these compatibility tests are only needed when dealing
1707 with ranges or a mix of range and anti-range. If VAR_VR and VR_P
1708 are both anti-ranges, they will always be compatible, because two
1709 anti-ranges will always have a non-empty intersection. */
1711 var_vr = get_value_range (var);
1713 /* We may need to make adjustments when VR_P and VAR_VR are numeric
1714 ranges or anti-ranges. */
1715 if (vr_p->type == VR_VARYING
1716 || vr_p->type == VR_UNDEFINED
1717 || var_vr->type == VR_VARYING
1718 || var_vr->type == VR_UNDEFINED
1719 || symbolic_range_p (vr_p)
1720 || symbolic_range_p (var_vr))
1723 if (var_vr->type == VR_RANGE && vr_p->type == VR_RANGE)
1725 /* If the two ranges have a non-empty intersection, we can
1726 refine the resulting range. Since the assert expression
1727 creates an equivalency and at the same time it asserts a
1728 predicate, we can take the intersection of the two ranges to
1729 get better precision. */
1730 if (value_ranges_intersect_p (var_vr, vr_p))
1732 /* Use the larger of the two minimums. */
1733 if (compare_values (vr_p->min, var_vr->min) == -1)
1738 /* Use the smaller of the two maximums. */
1739 if (compare_values (vr_p->max, var_vr->max) == 1)
1744 set_value_range (vr_p, vr_p->type, min, max, vr_p->equiv);
1748 /* The two ranges do not intersect, set the new range to
1749 VARYING, because we will not be able to do anything
1750 meaningful with it. */
1751 set_value_range_to_varying (vr_p);
1754 else if ((var_vr->type == VR_RANGE && vr_p->type == VR_ANTI_RANGE)
1755 || (var_vr->type == VR_ANTI_RANGE && vr_p->type == VR_RANGE))
1757 /* A range and an anti-range will cancel each other only if
1758 their ends are the same. For instance, in the example above,
1759 p_8's range ~[0, 0] and p_6's range [0, 0] are incompatible,
1760 so VR_P should be set to VR_VARYING. */
1761 if (compare_values (var_vr->min, vr_p->min) == 0
1762 && compare_values (var_vr->max, vr_p->max) == 0)
1763 set_value_range_to_varying (vr_p);
1766 tree min, max, anti_min, anti_max, real_min, real_max;
1769 /* We want to compute the logical AND of the two ranges;
1770 there are three cases to consider.
1773 1. The VR_ANTI_RANGE range is completely within the
1774 VR_RANGE and the endpoints of the ranges are
1775 different. In that case the resulting range
1776 should be whichever range is more precise.
1777 Typically that will be the VR_RANGE.
1779 2. The VR_ANTI_RANGE is completely disjoint from
1780 the VR_RANGE. In this case the resulting range
1781 should be the VR_RANGE.
1783 3. There is some overlap between the VR_ANTI_RANGE
1786 3a. If the high limit of the VR_ANTI_RANGE resides
1787 within the VR_RANGE, then the result is a new
1788 VR_RANGE starting at the high limit of the
1789 VR_ANTI_RANGE + 1 and extending to the
1790 high limit of the original VR_RANGE.
1792 3b. If the low limit of the VR_ANTI_RANGE resides
1793 within the VR_RANGE, then the result is a new
1794 VR_RANGE starting at the low limit of the original
1795 VR_RANGE and extending to the low limit of the
1796 VR_ANTI_RANGE - 1. */
1797 if (vr_p->type == VR_ANTI_RANGE)
1799 anti_min = vr_p->min;
1800 anti_max = vr_p->max;
1801 real_min = var_vr->min;
1802 real_max = var_vr->max;
1806 anti_min = var_vr->min;
1807 anti_max = var_vr->max;
1808 real_min = vr_p->min;
1809 real_max = vr_p->max;
1813 /* Case 1, VR_ANTI_RANGE completely within VR_RANGE,
1814 not including any endpoints. */
1815 if (compare_values (anti_max, real_max) == -1
1816 && compare_values (anti_min, real_min) == 1)
1818 /* If the range is covering the whole valid range of
1819 the type keep the anti-range. */
1820 if (!vrp_val_is_min (real_min)
1821 || !vrp_val_is_max (real_max))
1822 set_value_range (vr_p, VR_RANGE, real_min,
1823 real_max, vr_p->equiv);
1825 /* Case 2, VR_ANTI_RANGE completely disjoint from
1827 else if (compare_values (anti_min, real_max) == 1
1828 || compare_values (anti_max, real_min) == -1)
1830 set_value_range (vr_p, VR_RANGE, real_min,
1831 real_max, vr_p->equiv);
1833 /* Case 3a, the anti-range extends into the low
1834 part of the real range. Thus creating a new
1835 low for the real range. */
1836 else if (((cmp = compare_values (anti_max, real_min)) == 1
1838 && compare_values (anti_max, real_max) == -1)
1840 gcc_assert (!is_positive_overflow_infinity (anti_max));
1841 if (needs_overflow_infinity (TREE_TYPE (anti_max))
1842 && vrp_val_is_max (anti_max))
1844 if (!supports_overflow_infinity (TREE_TYPE (var_vr->min)))
1846 set_value_range_to_varying (vr_p);
1849 min = positive_overflow_infinity (TREE_TYPE (var_vr->min));
1851 else if (!POINTER_TYPE_P (TREE_TYPE (var_vr->min)))
1852 min = fold_build2 (PLUS_EXPR, TREE_TYPE (var_vr->min),
1854 build_int_cst (TREE_TYPE (var_vr->min), 1));
1856 min = fold_build2 (POINTER_PLUS_EXPR, TREE_TYPE (var_vr->min),
1857 anti_max, size_int (1));
1859 set_value_range (vr_p, VR_RANGE, min, max, vr_p->equiv);
1861 /* Case 3b, the anti-range extends into the high
1862 part of the real range. Thus creating a new
1863 higher for the real range. */
1864 else if (compare_values (anti_min, real_min) == 1
1865 && ((cmp = compare_values (anti_min, real_max)) == -1
1868 gcc_assert (!is_negative_overflow_infinity (anti_min));
1869 if (needs_overflow_infinity (TREE_TYPE (anti_min))
1870 && vrp_val_is_min (anti_min))
1872 if (!supports_overflow_infinity (TREE_TYPE (var_vr->min)))
1874 set_value_range_to_varying (vr_p);
1877 max = negative_overflow_infinity (TREE_TYPE (var_vr->min));
1879 else if (!POINTER_TYPE_P (TREE_TYPE (var_vr->min)))
1880 max = fold_build2 (MINUS_EXPR, TREE_TYPE (var_vr->min),
1882 build_int_cst (TREE_TYPE (var_vr->min), 1));
1884 max = fold_build2 (POINTER_PLUS_EXPR, TREE_TYPE (var_vr->min),
1888 set_value_range (vr_p, VR_RANGE, min, max, vr_p->equiv);
1895 /* Extract range information from SSA name VAR and store it in VR. If
1896 VAR has an interesting range, use it. Otherwise, create the
1897 range [VAR, VAR] and return it. This is useful in situations where
1898 we may have conditionals testing values of VARYING names. For
1905 Even if y_5 is deemed VARYING, we can determine that x_3 > y_5 is
1909 extract_range_from_ssa_name (value_range_t *vr, tree var)
1911 value_range_t *var_vr = get_value_range (var);
1913 if (var_vr->type != VR_UNDEFINED && var_vr->type != VR_VARYING)
1914 copy_value_range (vr, var_vr);
1916 set_value_range (vr, VR_RANGE, var, var, NULL);
1918 add_equivalence (&vr->equiv, var);
1922 /* Wrapper around int_const_binop. If the operation overflows and we
1923 are not using wrapping arithmetic, then adjust the result to be
1924 -INF or +INF depending on CODE, VAL1 and VAL2. This can return
1925 NULL_TREE if we need to use an overflow infinity representation but
1926 the type does not support it. */
1929 vrp_int_const_binop (enum tree_code code, tree val1, tree val2)
1933 res = int_const_binop (code, val1, val2, 0);
1935 /* If we are not using wrapping arithmetic, operate symbolically
1936 on -INF and +INF. */
1937 if (TYPE_OVERFLOW_WRAPS (TREE_TYPE (val1)))
1939 int checkz = compare_values (res, val1);
1940 bool overflow = false;
1942 /* Ensure that res = val1 [+*] val2 >= val1
1943 or that res = val1 - val2 <= val1. */
1944 if ((code == PLUS_EXPR
1945 && !(checkz == 1 || checkz == 0))
1946 || (code == MINUS_EXPR
1947 && !(checkz == 0 || checkz == -1)))
1951 /* Checking for multiplication overflow is done by dividing the
1952 output of the multiplication by the first input of the
1953 multiplication. If the result of that division operation is
1954 not equal to the second input of the multiplication, then the
1955 multiplication overflowed. */
1956 else if (code == MULT_EXPR && !integer_zerop (val1))
1958 tree tmp = int_const_binop (TRUNC_DIV_EXPR,
1961 int check = compare_values (tmp, val2);
1969 res = copy_node (res);
1970 TREE_OVERFLOW (res) = 1;
1974 else if ((TREE_OVERFLOW (res)
1975 && !TREE_OVERFLOW (val1)
1976 && !TREE_OVERFLOW (val2))
1977 || is_overflow_infinity (val1)
1978 || is_overflow_infinity (val2))
1980 /* If the operation overflowed but neither VAL1 nor VAL2 are
1981 overflown, return -INF or +INF depending on the operation
1982 and the combination of signs of the operands. */
1983 int sgn1 = tree_int_cst_sgn (val1);
1984 int sgn2 = tree_int_cst_sgn (val2);
1986 if (needs_overflow_infinity (TREE_TYPE (res))
1987 && !supports_overflow_infinity (TREE_TYPE (res)))
1990 /* We have to punt on adding infinities of different signs,
1991 since we can't tell what the sign of the result should be.
1992 Likewise for subtracting infinities of the same sign. */
1993 if (((code == PLUS_EXPR && sgn1 != sgn2)
1994 || (code == MINUS_EXPR && sgn1 == sgn2))
1995 && is_overflow_infinity (val1)
1996 && is_overflow_infinity (val2))
1999 /* Don't try to handle division or shifting of infinities. */
2000 if ((code == TRUNC_DIV_EXPR
2001 || code == FLOOR_DIV_EXPR
2002 || code == CEIL_DIV_EXPR
2003 || code == EXACT_DIV_EXPR
2004 || code == ROUND_DIV_EXPR
2005 || code == RSHIFT_EXPR)
2006 && (is_overflow_infinity (val1)
2007 || is_overflow_infinity (val2)))
2010 /* Notice that we only need to handle the restricted set of
2011 operations handled by extract_range_from_binary_expr.
2012 Among them, only multiplication, addition and subtraction
2013 can yield overflow without overflown operands because we
2014 are working with integral types only... except in the
2015 case VAL1 = -INF and VAL2 = -1 which overflows to +INF
2016 for division too. */
2018 /* For multiplication, the sign of the overflow is given
2019 by the comparison of the signs of the operands. */
2020 if ((code == MULT_EXPR && sgn1 == sgn2)
2021 /* For addition, the operands must be of the same sign
2022 to yield an overflow. Its sign is therefore that
2023 of one of the operands, for example the first. For
2024 infinite operands X + -INF is negative, not positive. */
2025 || (code == PLUS_EXPR
2027 ? !is_negative_overflow_infinity (val2)
2028 : is_positive_overflow_infinity (val2)))
2029 /* For subtraction, non-infinite operands must be of
2030 different signs to yield an overflow. Its sign is
2031 therefore that of the first operand or the opposite of
2032 that of the second operand. A first operand of 0 counts
2033 as positive here, for the corner case 0 - (-INF), which
2034 overflows, but must yield +INF. For infinite operands 0
2035 - INF is negative, not positive. */
2036 || (code == MINUS_EXPR
2038 ? !is_positive_overflow_infinity (val2)
2039 : is_negative_overflow_infinity (val2)))
2040 /* We only get in here with positive shift count, so the
2041 overflow direction is the same as the sign of val1.
2042 Actually rshift does not overflow at all, but we only
2043 handle the case of shifting overflowed -INF and +INF. */
2044 || (code == RSHIFT_EXPR
2046 /* For division, the only case is -INF / -1 = +INF. */
2047 || code == TRUNC_DIV_EXPR
2048 || code == FLOOR_DIV_EXPR
2049 || code == CEIL_DIV_EXPR
2050 || code == EXACT_DIV_EXPR
2051 || code == ROUND_DIV_EXPR)
2052 return (needs_overflow_infinity (TREE_TYPE (res))
2053 ? positive_overflow_infinity (TREE_TYPE (res))
2054 : TYPE_MAX_VALUE (TREE_TYPE (res)));
2056 return (needs_overflow_infinity (TREE_TYPE (res))
2057 ? negative_overflow_infinity (TREE_TYPE (res))
2058 : TYPE_MIN_VALUE (TREE_TYPE (res)));
2065 /* Extract range information from a binary expression EXPR based on
2066 the ranges of each of its operands and the expression code. */
2069 extract_range_from_binary_expr (value_range_t *vr,
2070 enum tree_code code,
2071 tree expr_type, tree op0, tree op1)
2073 enum value_range_type type;
2076 value_range_t vr0 = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
2077 value_range_t vr1 = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
2079 /* Not all binary expressions can be applied to ranges in a
2080 meaningful way. Handle only arithmetic operations. */
2081 if (code != PLUS_EXPR
2082 && code != MINUS_EXPR
2083 && code != POINTER_PLUS_EXPR
2084 && code != MULT_EXPR
2085 && code != TRUNC_DIV_EXPR
2086 && code != FLOOR_DIV_EXPR
2087 && code != CEIL_DIV_EXPR
2088 && code != EXACT_DIV_EXPR
2089 && code != ROUND_DIV_EXPR
2090 && code != RSHIFT_EXPR
2093 && code != BIT_AND_EXPR
2094 && code != BIT_IOR_EXPR
2095 && code != TRUTH_AND_EXPR
2096 && code != TRUTH_OR_EXPR)
2098 /* We can still do constant propagation here. */
2099 tree const_op0 = op_with_constant_singleton_value_range (op0);
2100 tree const_op1 = op_with_constant_singleton_value_range (op1);
2101 if (const_op0 || const_op1)
2103 tree tem = fold_binary (code, expr_type,
2104 const_op0 ? const_op0 : op0,
2105 const_op1 ? const_op1 : op1);
2107 && is_gimple_min_invariant (tem)
2108 && !is_overflow_infinity (tem))
2110 set_value_range (vr, VR_RANGE, tem, tem, NULL);
2114 set_value_range_to_varying (vr);
2118 /* Get value ranges for each operand. For constant operands, create
2119 a new value range with the operand to simplify processing. */
2120 if (TREE_CODE (op0) == SSA_NAME)
2121 vr0 = *(get_value_range (op0));
2122 else if (is_gimple_min_invariant (op0))
2123 set_value_range_to_value (&vr0, op0, NULL);
2125 set_value_range_to_varying (&vr0);
2127 if (TREE_CODE (op1) == SSA_NAME)
2128 vr1 = *(get_value_range (op1));
2129 else if (is_gimple_min_invariant (op1))
2130 set_value_range_to_value (&vr1, op1, NULL);
2132 set_value_range_to_varying (&vr1);
2134 /* If either range is UNDEFINED, so is the result. */
2135 if (vr0.type == VR_UNDEFINED || vr1.type == VR_UNDEFINED)
2137 set_value_range_to_undefined (vr);
2141 /* The type of the resulting value range defaults to VR0.TYPE. */
2144 /* Refuse to operate on VARYING ranges, ranges of different kinds
2145 and symbolic ranges. As an exception, we allow BIT_AND_EXPR
2146 because we may be able to derive a useful range even if one of
2147 the operands is VR_VARYING or symbolic range. Similarly for
2148 divisions. TODO, we may be able to derive anti-ranges in
2150 if (code != BIT_AND_EXPR
2151 && code != TRUTH_AND_EXPR
2152 && code != TRUTH_OR_EXPR
2153 && code != TRUNC_DIV_EXPR
2154 && code != FLOOR_DIV_EXPR
2155 && code != CEIL_DIV_EXPR
2156 && code != EXACT_DIV_EXPR
2157 && code != ROUND_DIV_EXPR
2158 && (vr0.type == VR_VARYING
2159 || vr1.type == VR_VARYING
2160 || vr0.type != vr1.type
2161 || symbolic_range_p (&vr0)
2162 || symbolic_range_p (&vr1)))
2164 set_value_range_to_varying (vr);
2168 /* Now evaluate the expression to determine the new range. */
2169 if (POINTER_TYPE_P (expr_type)
2170 || POINTER_TYPE_P (TREE_TYPE (op0))
2171 || POINTER_TYPE_P (TREE_TYPE (op1)))
2173 if (code == MIN_EXPR || code == MAX_EXPR)
2175 /* For MIN/MAX expressions with pointers, we only care about
2176 nullness, if both are non null, then the result is nonnull.
2177 If both are null, then the result is null. Otherwise they
2179 if (range_is_nonnull (&vr0) && range_is_nonnull (&vr1))
2180 set_value_range_to_nonnull (vr, expr_type);
2181 else if (range_is_null (&vr0) && range_is_null (&vr1))
2182 set_value_range_to_null (vr, expr_type);
2184 set_value_range_to_varying (vr);
2188 gcc_assert (code == POINTER_PLUS_EXPR);
2189 /* For pointer types, we are really only interested in asserting
2190 whether the expression evaluates to non-NULL. */
2191 if (range_is_nonnull (&vr0) || range_is_nonnull (&vr1))
2192 set_value_range_to_nonnull (vr, expr_type);
2193 else if (range_is_null (&vr0) && range_is_null (&vr1))
2194 set_value_range_to_null (vr, expr_type);
2196 set_value_range_to_varying (vr);
2201 /* For integer ranges, apply the operation to each end of the
2202 range and see what we end up with. */
2203 if (code == TRUTH_AND_EXPR
2204 || code == TRUTH_OR_EXPR)
2206 /* If one of the operands is zero, we know that the whole
2207 expression evaluates zero. */
2208 if (code == TRUTH_AND_EXPR
2209 && ((vr0.type == VR_RANGE
2210 && integer_zerop (vr0.min)
2211 && integer_zerop (vr0.max))
2212 || (vr1.type == VR_RANGE
2213 && integer_zerop (vr1.min)
2214 && integer_zerop (vr1.max))))
2217 min = max = build_int_cst (expr_type, 0);
2219 /* If one of the operands is one, we know that the whole
2220 expression evaluates one. */
2221 else if (code == TRUTH_OR_EXPR
2222 && ((vr0.type == VR_RANGE
2223 && integer_onep (vr0.min)
2224 && integer_onep (vr0.max))
2225 || (vr1.type == VR_RANGE
2226 && integer_onep (vr1.min)
2227 && integer_onep (vr1.max))))
2230 min = max = build_int_cst (expr_type, 1);
2232 else if (vr0.type != VR_VARYING
2233 && vr1.type != VR_VARYING
2234 && vr0.type == vr1.type
2235 && !symbolic_range_p (&vr0)
2236 && !overflow_infinity_range_p (&vr0)
2237 && !symbolic_range_p (&vr1)
2238 && !overflow_infinity_range_p (&vr1))
2240 /* Boolean expressions cannot be folded with int_const_binop. */
2241 min = fold_binary (code, expr_type, vr0.min, vr1.min);
2242 max = fold_binary (code, expr_type, vr0.max, vr1.max);
2246 /* The result of a TRUTH_*_EXPR is always true or false. */
2247 set_value_range_to_truthvalue (vr, expr_type);
2251 else if (code == PLUS_EXPR
2253 || code == MAX_EXPR)
2255 /* If we have a PLUS_EXPR with two VR_ANTI_RANGEs, drop to
2256 VR_VARYING. It would take more effort to compute a precise
2257 range for such a case. For example, if we have op0 == 1 and
2258 op1 == -1 with their ranges both being ~[0,0], we would have
2259 op0 + op1 == 0, so we cannot claim that the sum is in ~[0,0].
2260 Note that we are guaranteed to have vr0.type == vr1.type at
2262 if (vr0.type == VR_ANTI_RANGE)
2264 if (code == PLUS_EXPR)
2266 set_value_range_to_varying (vr);
2269 /* For MIN_EXPR and MAX_EXPR with two VR_ANTI_RANGEs,
2270 the resulting VR_ANTI_RANGE is the same - intersection
2271 of the two ranges. */
2272 min = vrp_int_const_binop (MAX_EXPR, vr0.min, vr1.min);
2273 max = vrp_int_const_binop (MIN_EXPR, vr0.max, vr1.max);
2277 /* For operations that make the resulting range directly
2278 proportional to the original ranges, apply the operation to
2279 the same end of each range. */
2280 min = vrp_int_const_binop (code, vr0.min, vr1.min);
2281 max = vrp_int_const_binop (code, vr0.max, vr1.max);
2284 else if (code == MULT_EXPR
2285 || code == TRUNC_DIV_EXPR
2286 || code == FLOOR_DIV_EXPR
2287 || code == CEIL_DIV_EXPR
2288 || code == EXACT_DIV_EXPR
2289 || code == ROUND_DIV_EXPR
2290 || code == RSHIFT_EXPR)
2296 /* If we have an unsigned MULT_EXPR with two VR_ANTI_RANGEs,
2297 drop to VR_VARYING. It would take more effort to compute a
2298 precise range for such a case. For example, if we have
2299 op0 == 65536 and op1 == 65536 with their ranges both being
2300 ~[0,0] on a 32-bit machine, we would have op0 * op1 == 0, so
2301 we cannot claim that the product is in ~[0,0]. Note that we
2302 are guaranteed to have vr0.type == vr1.type at this
2304 if (code == MULT_EXPR
2305 && vr0.type == VR_ANTI_RANGE
2306 && !TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (op0)))
2308 set_value_range_to_varying (vr);
2312 /* If we have a RSHIFT_EXPR with any shift values outside [0..prec-1],
2313 then drop to VR_VARYING. Outside of this range we get undefined
2314 behavior from the shift operation. We cannot even trust
2315 SHIFT_COUNT_TRUNCATED at this stage, because that applies to rtl
2316 shifts, and the operation at the tree level may be widened. */
2317 if (code == RSHIFT_EXPR)
2319 if (vr1.type == VR_ANTI_RANGE
2320 || !vrp_expr_computes_nonnegative (op1, &sop)
2322 (build_int_cst (TREE_TYPE (vr1.max),
2323 TYPE_PRECISION (expr_type) - 1),
2326 set_value_range_to_varying (vr);
2331 else if ((code == TRUNC_DIV_EXPR
2332 || code == FLOOR_DIV_EXPR
2333 || code == CEIL_DIV_EXPR
2334 || code == EXACT_DIV_EXPR
2335 || code == ROUND_DIV_EXPR)
2336 && (vr0.type != VR_RANGE || symbolic_range_p (&vr0)))
2338 /* For division, if op1 has VR_RANGE but op0 does not, something
2339 can be deduced just from that range. Say [min, max] / [4, max]
2340 gives [min / 4, max / 4] range. */
2341 if (vr1.type == VR_RANGE
2342 && !symbolic_range_p (&vr1)
2343 && !range_includes_zero_p (&vr1))
2345 vr0.type = type = VR_RANGE;
2346 vr0.min = vrp_val_min (TREE_TYPE (op0));
2347 vr0.max = vrp_val_max (TREE_TYPE (op1));
2351 set_value_range_to_varying (vr);
2356 /* For divisions, if op0 is VR_RANGE, we can deduce a range
2357 even if op1 is VR_VARYING, VR_ANTI_RANGE, symbolic or can
2359 if ((code == TRUNC_DIV_EXPR
2360 || code == FLOOR_DIV_EXPR
2361 || code == CEIL_DIV_EXPR
2362 || code == EXACT_DIV_EXPR
2363 || code == ROUND_DIV_EXPR)
2364 && vr0.type == VR_RANGE
2365 && (vr1.type != VR_RANGE
2366 || symbolic_range_p (&vr1)
2367 || range_includes_zero_p (&vr1)))
2369 tree zero = build_int_cst (TREE_TYPE (vr0.min), 0);
2375 if (vrp_expr_computes_nonnegative (op1, &sop) && !sop)
2377 /* For unsigned division or when divisor is known
2378 to be non-negative, the range has to cover
2379 all numbers from 0 to max for positive max
2380 and all numbers from min to 0 for negative min. */
2381 cmp = compare_values (vr0.max, zero);
2384 else if (cmp == 0 || cmp == 1)
2388 cmp = compare_values (vr0.min, zero);
2391 else if (cmp == 0 || cmp == -1)
2398 /* Otherwise the range is -max .. max or min .. -min
2399 depending on which bound is bigger in absolute value,
2400 as the division can change the sign. */
2401 abs_extent_range (vr, vr0.min, vr0.max);
2404 if (type == VR_VARYING)
2406 set_value_range_to_varying (vr);
2411 /* Multiplications and divisions are a bit tricky to handle,
2412 depending on the mix of signs we have in the two ranges, we
2413 need to operate on different values to get the minimum and
2414 maximum values for the new range. One approach is to figure
2415 out all the variations of range combinations and do the
2418 However, this involves several calls to compare_values and it
2419 is pretty convoluted. It's simpler to do the 4 operations
2420 (MIN0 OP MIN1, MIN0 OP MAX1, MAX0 OP MIN1 and MAX0 OP MAX0 OP
2421 MAX1) and then figure the smallest and largest values to form
2425 gcc_assert ((vr0.type == VR_RANGE
2426 || (code == MULT_EXPR && vr0.type == VR_ANTI_RANGE))
2427 && vr0.type == vr1.type);
2429 /* Compute the 4 cross operations. */
2431 val[0] = vrp_int_const_binop (code, vr0.min, vr1.min);
2432 if (val[0] == NULL_TREE)
2435 if (vr1.max == vr1.min)
2439 val[1] = vrp_int_const_binop (code, vr0.min, vr1.max);
2440 if (val[1] == NULL_TREE)
2444 if (vr0.max == vr0.min)
2448 val[2] = vrp_int_const_binop (code, vr0.max, vr1.min);
2449 if (val[2] == NULL_TREE)
2453 if (vr0.min == vr0.max || vr1.min == vr1.max)
2457 val[3] = vrp_int_const_binop (code, vr0.max, vr1.max);
2458 if (val[3] == NULL_TREE)
2464 set_value_range_to_varying (vr);
2468 /* Set MIN to the minimum of VAL[i] and MAX to the maximum
2472 for (i = 1; i < 4; i++)
2474 if (!is_gimple_min_invariant (min)
2475 || (TREE_OVERFLOW (min) && !is_overflow_infinity (min))
2476 || !is_gimple_min_invariant (max)
2477 || (TREE_OVERFLOW (max) && !is_overflow_infinity (max)))
2482 if (!is_gimple_min_invariant (val[i])
2483 || (TREE_OVERFLOW (val[i])
2484 && !is_overflow_infinity (val[i])))
2486 /* If we found an overflowed value, set MIN and MAX
2487 to it so that we set the resulting range to
2493 if (compare_values (val[i], min) == -1)
2496 if (compare_values (val[i], max) == 1)
2502 else if (code == MINUS_EXPR)
2504 /* If we have a MINUS_EXPR with two VR_ANTI_RANGEs, drop to
2505 VR_VARYING. It would take more effort to compute a precise
2506 range for such a case. For example, if we have op0 == 1 and
2507 op1 == 1 with their ranges both being ~[0,0], we would have
2508 op0 - op1 == 0, so we cannot claim that the difference is in
2509 ~[0,0]. Note that we are guaranteed to have
2510 vr0.type == vr1.type at this point. */
2511 if (vr0.type == VR_ANTI_RANGE)
2513 set_value_range_to_varying (vr);
2517 /* For MINUS_EXPR, apply the operation to the opposite ends of
2519 min = vrp_int_const_binop (code, vr0.min, vr1.max);
2520 max = vrp_int_const_binop (code, vr0.max, vr1.min);
2522 else if (code == BIT_AND_EXPR)
2524 if (vr0.type == VR_RANGE
2525 && vr0.min == vr0.max
2526 && TREE_CODE (vr0.max) == INTEGER_CST
2527 && !TREE_OVERFLOW (vr0.max)
2528 && tree_int_cst_sgn (vr0.max) >= 0)
2530 min = build_int_cst (expr_type, 0);
2533 else if (vr1.type == VR_RANGE
2534 && vr1.min == vr1.max
2535 && TREE_CODE (vr1.max) == INTEGER_CST
2536 && !TREE_OVERFLOW (vr1.max)
2537 && tree_int_cst_sgn (vr1.max) >= 0)
2540 min = build_int_cst (expr_type, 0);
2545 set_value_range_to_varying (vr);
2549 else if (code == BIT_IOR_EXPR)
2551 if (vr0.type == VR_RANGE
2552 && vr1.type == VR_RANGE
2553 && TREE_CODE (vr0.min) == INTEGER_CST
2554 && TREE_CODE (vr1.min) == INTEGER_CST
2555 && TREE_CODE (vr0.max) == INTEGER_CST
2556 && TREE_CODE (vr1.max) == INTEGER_CST
2557 && tree_int_cst_sgn (vr0.min) >= 0
2558 && tree_int_cst_sgn (vr1.min) >= 0)
2560 double_int vr0_max = tree_to_double_int (vr0.max);
2561 double_int vr1_max = tree_to_double_int (vr1.max);
2564 /* Set all bits to the right of the most significant one to 1.
2565 For example, [0, 4] | [4, 4] = [4, 7]. */
2566 ior_max.low = vr0_max.low | vr1_max.low;
2567 ior_max.high = vr0_max.high | vr1_max.high;
2568 if (ior_max.high != 0)
2570 ior_max.low = ~(unsigned HOST_WIDE_INT)0u;
2571 ior_max.high |= ((HOST_WIDE_INT) 1
2572 << floor_log2 (ior_max.high)) - 1;
2574 else if (ior_max.low != 0)
2575 ior_max.low |= ((unsigned HOST_WIDE_INT) 1u
2576 << floor_log2 (ior_max.low)) - 1;
2578 /* Both of these endpoints are conservative. */
2579 min = vrp_int_const_binop (MAX_EXPR, vr0.min, vr1.min);
2580 max = double_int_to_tree (expr_type, ior_max);
2584 set_value_range_to_varying (vr);
2591 /* If either MIN or MAX overflowed, then set the resulting range to
2592 VARYING. But we do accept an overflow infinity
2594 if (min == NULL_TREE
2595 || !is_gimple_min_invariant (min)
2596 || (TREE_OVERFLOW (min) && !is_overflow_infinity (min))
2598 || !is_gimple_min_invariant (max)
2599 || (TREE_OVERFLOW (max) && !is_overflow_infinity (max)))
2601 set_value_range_to_varying (vr);
2607 2) [-INF, +-INF(OVF)]
2608 3) [+-INF(OVF), +INF]
2609 4) [+-INF(OVF), +-INF(OVF)]
2610 We learn nothing when we have INF and INF(OVF) on both sides.
2611 Note that we do accept [-INF, -INF] and [+INF, +INF] without
2613 if ((vrp_val_is_min (min) || is_overflow_infinity (min))
2614 && (vrp_val_is_max (max) || is_overflow_infinity (max)))
2616 set_value_range_to_varying (vr);
2620 cmp = compare_values (min, max);
2621 if (cmp == -2 || cmp == 1)
2623 /* If the new range has its limits swapped around (MIN > MAX),
2624 then the operation caused one of them to wrap around, mark
2625 the new range VARYING. */
2626 set_value_range_to_varying (vr);
2629 set_value_range (vr, type, min, max, NULL);
2633 /* Extract range information from a unary expression EXPR based on
2634 the range of its operand and the expression code. */
2637 extract_range_from_unary_expr (value_range_t *vr, enum tree_code code,
2638 tree type, tree op0)
2642 value_range_t vr0 = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
2644 /* Refuse to operate on certain unary expressions for which we
2645 cannot easily determine a resulting range. */
2646 if (code == FIX_TRUNC_EXPR
2647 || code == FLOAT_EXPR
2648 || code == BIT_NOT_EXPR
2649 || code == CONJ_EXPR)
2651 /* We can still do constant propagation here. */
2652 if ((op0 = op_with_constant_singleton_value_range (op0)) != NULL_TREE)
2654 tree tem = fold_unary (code, type, op0);
2656 && is_gimple_min_invariant (tem)
2657 && !is_overflow_infinity (tem))
2659 set_value_range (vr, VR_RANGE, tem, tem, NULL);
2663 set_value_range_to_varying (vr);
2667 /* Get value ranges for the operand. For constant operands, create
2668 a new value range with the operand to simplify processing. */
2669 if (TREE_CODE (op0) == SSA_NAME)
2670 vr0 = *(get_value_range (op0));
2671 else if (is_gimple_min_invariant (op0))
2672 set_value_range_to_value (&vr0, op0, NULL);
2674 set_value_range_to_varying (&vr0);
2676 /* If VR0 is UNDEFINED, so is the result. */
2677 if (vr0.type == VR_UNDEFINED)
2679 set_value_range_to_undefined (vr);
2683 /* Refuse to operate on symbolic ranges, or if neither operand is
2684 a pointer or integral type. */
2685 if ((!INTEGRAL_TYPE_P (TREE_TYPE (op0))
2686 && !POINTER_TYPE_P (TREE_TYPE (op0)))
2687 || (vr0.type != VR_VARYING
2688 && symbolic_range_p (&vr0)))
2690 set_value_range_to_varying (vr);
2694 /* If the expression involves pointers, we are only interested in
2695 determining if it evaluates to NULL [0, 0] or non-NULL (~[0, 0]). */
2696 if (POINTER_TYPE_P (type) || POINTER_TYPE_P (TREE_TYPE (op0)))
2701 if (range_is_nonnull (&vr0)
2702 || (tree_unary_nonzero_warnv_p (code, type, op0, &sop)
2704 set_value_range_to_nonnull (vr, type);
2705 else if (range_is_null (&vr0))
2706 set_value_range_to_null (vr, type);
2708 set_value_range_to_varying (vr);
2713 /* Handle unary expressions on integer ranges. */
2714 if (CONVERT_EXPR_CODE_P (code)
2715 && INTEGRAL_TYPE_P (type)
2716 && INTEGRAL_TYPE_P (TREE_TYPE (op0)))
2718 tree inner_type = TREE_TYPE (op0);
2719 tree outer_type = type;
2721 /* Always use base-types here. This is important for the
2722 correct signedness. */
2723 if (TREE_TYPE (inner_type))
2724 inner_type = TREE_TYPE (inner_type);
2725 if (TREE_TYPE (outer_type))
2726 outer_type = TREE_TYPE (outer_type);
2728 /* If VR0 is varying and we increase the type precision, assume
2729 a full range for the following transformation. */
2730 if (vr0.type == VR_VARYING
2731 && TYPE_PRECISION (inner_type) < TYPE_PRECISION (outer_type))
2733 vr0.type = VR_RANGE;
2734 vr0.min = TYPE_MIN_VALUE (inner_type);
2735 vr0.max = TYPE_MAX_VALUE (inner_type);
2738 /* If VR0 is a constant range or anti-range and the conversion is
2739 not truncating we can convert the min and max values and
2740 canonicalize the resulting range. Otherwise we can do the
2741 conversion if the size of the range is less than what the
2742 precision of the target type can represent and the range is
2743 not an anti-range. */
2744 if ((vr0.type == VR_RANGE
2745 || vr0.type == VR_ANTI_RANGE)
2746 && TREE_CODE (vr0.min) == INTEGER_CST
2747 && TREE_CODE (vr0.max) == INTEGER_CST
2748 && !is_overflow_infinity (vr0.min)
2749 && !is_overflow_infinity (vr0.max)
2750 && (TYPE_PRECISION (outer_type) >= TYPE_PRECISION (inner_type)
2751 || (vr0.type == VR_RANGE
2752 && integer_zerop (int_const_binop (RSHIFT_EXPR,
2753 int_const_binop (MINUS_EXPR, vr0.max, vr0.min, 0),
2754 size_int (TYPE_PRECISION (outer_type)), 0)))))
2756 tree new_min, new_max;
2757 new_min = force_fit_type_double (outer_type,
2758 TREE_INT_CST_LOW (vr0.min),
2759 TREE_INT_CST_HIGH (vr0.min), 0, 0);
2760 new_max = force_fit_type_double (outer_type,
2761 TREE_INT_CST_LOW (vr0.max),
2762 TREE_INT_CST_HIGH (vr0.max), 0, 0);
2763 set_and_canonicalize_value_range (vr, vr0.type,
2764 new_min, new_max, NULL);
2768 set_value_range_to_varying (vr);
2772 /* Conversion of a VR_VARYING value to a wider type can result
2773 in a usable range. So wait until after we've handled conversions
2774 before dropping the result to VR_VARYING if we had a source
2775 operand that is VR_VARYING. */
2776 if (vr0.type == VR_VARYING)
2778 set_value_range_to_varying (vr);
2782 /* Apply the operation to each end of the range and see what we end
2784 if (code == NEGATE_EXPR
2785 && !TYPE_UNSIGNED (type))
2787 /* NEGATE_EXPR flips the range around. We need to treat
2788 TYPE_MIN_VALUE specially. */
2789 if (is_positive_overflow_infinity (vr0.max))
2790 min = negative_overflow_infinity (type);
2791 else if (is_negative_overflow_infinity (vr0.max))
2792 min = positive_overflow_infinity (type);
2793 else if (!vrp_val_is_min (vr0.max))
2794 min = fold_unary_to_constant (code, type, vr0.max);
2795 else if (needs_overflow_infinity (type))
2797 if (supports_overflow_infinity (type)
2798 && !is_overflow_infinity (vr0.min)
2799 && !vrp_val_is_min (vr0.min))
2800 min = positive_overflow_infinity (type);
2803 set_value_range_to_varying (vr);
2808 min = TYPE_MIN_VALUE (type);
2810 if (is_positive_overflow_infinity (vr0.min))
2811 max = negative_overflow_infinity (type);
2812 else if (is_negative_overflow_infinity (vr0.min))
2813 max = positive_overflow_infinity (type);
2814 else if (!vrp_val_is_min (vr0.min))
2815 max = fold_unary_to_constant (code, type, vr0.min);
2816 else if (needs_overflow_infinity (type))
2818 if (supports_overflow_infinity (type))
2819 max = positive_overflow_infinity (type);
2822 set_value_range_to_varying (vr);
2827 max = TYPE_MIN_VALUE (type);
2829 else if (code == NEGATE_EXPR
2830 && TYPE_UNSIGNED (type))
2832 if (!range_includes_zero_p (&vr0))
2834 max = fold_unary_to_constant (code, type, vr0.min);
2835 min = fold_unary_to_constant (code, type, vr0.max);
2839 if (range_is_null (&vr0))
2840 set_value_range_to_null (vr, type);
2842 set_value_range_to_varying (vr);
2846 else if (code == ABS_EXPR
2847 && !TYPE_UNSIGNED (type))
2849 /* -TYPE_MIN_VALUE = TYPE_MIN_VALUE with flag_wrapv so we can't get a
2851 if (!TYPE_OVERFLOW_UNDEFINED (type)
2852 && ((vr0.type == VR_RANGE
2853 && vrp_val_is_min (vr0.min))
2854 || (vr0.type == VR_ANTI_RANGE
2855 && !vrp_val_is_min (vr0.min)
2856 && !range_includes_zero_p (&vr0))))
2858 set_value_range_to_varying (vr);
2862 /* ABS_EXPR may flip the range around, if the original range
2863 included negative values. */
2864 if (is_overflow_infinity (vr0.min))
2865 min = positive_overflow_infinity (type);
2866 else if (!vrp_val_is_min (vr0.min))
2867 min = fold_unary_to_constant (code, type, vr0.min);
2868 else if (!needs_overflow_infinity (type))
2869 min = TYPE_MAX_VALUE (type);
2870 else if (supports_overflow_infinity (type))
2871 min = positive_overflow_infinity (type);
2874 set_value_range_to_varying (vr);
2878 if (is_overflow_infinity (vr0.max))
2879 max = positive_overflow_infinity (type);
2880 else if (!vrp_val_is_min (vr0.max))
2881 max = fold_unary_to_constant (code, type, vr0.max);
2882 else if (!needs_overflow_infinity (type))
2883 max = TYPE_MAX_VALUE (type);
2884 else if (supports_overflow_infinity (type)
2885 /* We shouldn't generate [+INF, +INF] as set_value_range
2886 doesn't like this and ICEs. */
2887 && !is_positive_overflow_infinity (min))
2888 max = positive_overflow_infinity (type);
2891 set_value_range_to_varying (vr);
2895 cmp = compare_values (min, max);
2897 /* If a VR_ANTI_RANGEs contains zero, then we have
2898 ~[-INF, min(MIN, MAX)]. */
2899 if (vr0.type == VR_ANTI_RANGE)
2901 if (range_includes_zero_p (&vr0))
2903 /* Take the lower of the two values. */
2907 /* Create ~[-INF, min (abs(MIN), abs(MAX))]
2908 or ~[-INF + 1, min (abs(MIN), abs(MAX))] when
2909 flag_wrapv is set and the original anti-range doesn't include
2910 TYPE_MIN_VALUE, remember -TYPE_MIN_VALUE = TYPE_MIN_VALUE. */
2911 if (TYPE_OVERFLOW_WRAPS (type))
2913 tree type_min_value = TYPE_MIN_VALUE (type);
2915 min = (vr0.min != type_min_value
2916 ? int_const_binop (PLUS_EXPR, type_min_value,
2917 integer_one_node, 0)
2922 if (overflow_infinity_range_p (&vr0))
2923 min = negative_overflow_infinity (type);
2925 min = TYPE_MIN_VALUE (type);
2930 /* All else has failed, so create the range [0, INF], even for
2931 flag_wrapv since TYPE_MIN_VALUE is in the original
2933 vr0.type = VR_RANGE;
2934 min = build_int_cst (type, 0);
2935 if (needs_overflow_infinity (type))
2937 if (supports_overflow_infinity (type))
2938 max = positive_overflow_infinity (type);
2941 set_value_range_to_varying (vr);
2946 max = TYPE_MAX_VALUE (type);
2950 /* If the range contains zero then we know that the minimum value in the
2951 range will be zero. */
2952 else if (range_includes_zero_p (&vr0))
2956 min = build_int_cst (type, 0);
2960 /* If the range was reversed, swap MIN and MAX. */
2971 /* Otherwise, operate on each end of the range. */
2972 min = fold_unary_to_constant (code, type, vr0.min);
2973 max = fold_unary_to_constant (code, type, vr0.max);
2975 if (needs_overflow_infinity (type))
2977 gcc_assert (code != NEGATE_EXPR && code != ABS_EXPR);
2979 /* If both sides have overflowed, we don't know
2981 if ((is_overflow_infinity (vr0.min)
2982 || TREE_OVERFLOW (min))
2983 && (is_overflow_infinity (vr0.max)
2984 || TREE_OVERFLOW (max)))
2986 set_value_range_to_varying (vr);
2990 if (is_overflow_infinity (vr0.min))
2992 else if (TREE_OVERFLOW (min))
2994 if (supports_overflow_infinity (type))
2995 min = (tree_int_cst_sgn (min) >= 0
2996 ? positive_overflow_infinity (TREE_TYPE (min))
2997 : negative_overflow_infinity (TREE_TYPE (min)));
3000 set_value_range_to_varying (vr);
3005 if (is_overflow_infinity (vr0.max))
3007 else if (TREE_OVERFLOW (max))
3009 if (supports_overflow_infinity (type))
3010 max = (tree_int_cst_sgn (max) >= 0
3011 ? positive_overflow_infinity (TREE_TYPE (max))
3012 : negative_overflow_infinity (TREE_TYPE (max)));
3015 set_value_range_to_varying (vr);
3022 cmp = compare_values (min, max);
3023 if (cmp == -2 || cmp == 1)
3025 /* If the new range has its limits swapped around (MIN > MAX),
3026 then the operation caused one of them to wrap around, mark
3027 the new range VARYING. */
3028 set_value_range_to_varying (vr);
3031 set_value_range (vr, vr0.type, min, max, NULL);
3035 /* Extract range information from a conditional expression EXPR based on
3036 the ranges of each of its operands and the expression code. */
3039 extract_range_from_cond_expr (value_range_t *vr, tree expr)
3042 value_range_t vr0 = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
3043 value_range_t vr1 = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
3045 /* Get value ranges for each operand. For constant operands, create
3046 a new value range with the operand to simplify processing. */
3047 op0 = COND_EXPR_THEN (expr);
3048 if (TREE_CODE (op0) == SSA_NAME)
3049 vr0 = *(get_value_range (op0));
3050 else if (is_gimple_min_invariant (op0))
3051 set_value_range_to_value (&vr0, op0, NULL);
3053 set_value_range_to_varying (&vr0);
3055 op1 = COND_EXPR_ELSE (expr);
3056 if (TREE_CODE (op1) == SSA_NAME)
3057 vr1 = *(get_value_range (op1));
3058 else if (is_gimple_min_invariant (op1))
3059 set_value_range_to_value (&vr1, op1, NULL);
3061 set_value_range_to_varying (&vr1);
3063 /* The resulting value range is the union of the operand ranges */
3064 vrp_meet (&vr0, &vr1);
3065 copy_value_range (vr, &vr0);
3069 /* Extract range information from a comparison expression EXPR based
3070 on the range of its operand and the expression code. */
3073 extract_range_from_comparison (value_range_t *vr, enum tree_code code,
3074 tree type, tree op0, tree op1)
3079 val = vrp_evaluate_conditional_warnv_with_ops (code, op0, op1, false, &sop,
3082 /* A disadvantage of using a special infinity as an overflow
3083 representation is that we lose the ability to record overflow
3084 when we don't have an infinity. So we have to ignore a result
3085 which relies on overflow. */
3087 if (val && !is_overflow_infinity (val) && !sop)
3089 /* Since this expression was found on the RHS of an assignment,
3090 its type may be different from _Bool. Convert VAL to EXPR's
3092 val = fold_convert (type, val);
3093 if (is_gimple_min_invariant (val))
3094 set_value_range_to_value (vr, val, vr->equiv);
3096 set_value_range (vr, VR_RANGE, val, val, vr->equiv);
3099 /* The result of a comparison is always true or false. */
3100 set_value_range_to_truthvalue (vr, type);
3103 /* Try to derive a nonnegative or nonzero range out of STMT relying
3104 primarily on generic routines in fold in conjunction with range data.
3105 Store the result in *VR */
3108 extract_range_basic (value_range_t *vr, gimple stmt)
3111 tree type = gimple_expr_type (stmt);
3113 if (INTEGRAL_TYPE_P (type)
3114 && gimple_stmt_nonnegative_warnv_p (stmt, &sop))
3115 set_value_range_to_nonnegative (vr, type,
3116 sop || stmt_overflow_infinity (stmt));
3117 else if (vrp_stmt_computes_nonzero (stmt, &sop)
3119 set_value_range_to_nonnull (vr, type);
3121 set_value_range_to_varying (vr);
3125 /* Try to compute a useful range out of assignment STMT and store it
3129 extract_range_from_assignment (value_range_t *vr, gimple stmt)
3131 enum tree_code code = gimple_assign_rhs_code (stmt);
3133 if (code == ASSERT_EXPR)
3134 extract_range_from_assert (vr, gimple_assign_rhs1 (stmt));
3135 else if (code == SSA_NAME)
3136 extract_range_from_ssa_name (vr, gimple_assign_rhs1 (stmt));
3137 else if (TREE_CODE_CLASS (code) == tcc_binary
3138 || code == TRUTH_AND_EXPR
3139 || code == TRUTH_OR_EXPR
3140 || code == TRUTH_XOR_EXPR)
3141 extract_range_from_binary_expr (vr, gimple_assign_rhs_code (stmt),
3142 gimple_expr_type (stmt),
3143 gimple_assign_rhs1 (stmt),
3144 gimple_assign_rhs2 (stmt));
3145 else if (TREE_CODE_CLASS (code) == tcc_unary)
3146 extract_range_from_unary_expr (vr, gimple_assign_rhs_code (stmt),
3147 gimple_expr_type (stmt),
3148 gimple_assign_rhs1 (stmt));
3149 else if (code == COND_EXPR)
3150 extract_range_from_cond_expr (vr, gimple_assign_rhs1 (stmt));
3151 else if (TREE_CODE_CLASS (code) == tcc_comparison)
3152 extract_range_from_comparison (vr, gimple_assign_rhs_code (stmt),
3153 gimple_expr_type (stmt),
3154 gimple_assign_rhs1 (stmt),
3155 gimple_assign_rhs2 (stmt));
3156 else if (get_gimple_rhs_class (code) == GIMPLE_SINGLE_RHS
3157 && is_gimple_min_invariant (gimple_assign_rhs1 (stmt)))
3158 set_value_range_to_value (vr, gimple_assign_rhs1 (stmt), NULL);
3160 set_value_range_to_varying (vr);
3162 if (vr->type == VR_VARYING)
3163 extract_range_basic (vr, stmt);
3166 /* Given a range VR, a LOOP and a variable VAR, determine whether it
3167 would be profitable to adjust VR using scalar evolution information
3168 for VAR. If so, update VR with the new limits. */
3171 adjust_range_with_scev (value_range_t *vr, struct loop *loop,
3172 gimple stmt, tree var)
3174 tree init, step, chrec, tmin, tmax, min, max, type;
3175 enum ev_direction dir;
3177 /* TODO. Don't adjust anti-ranges. An anti-range may provide
3178 better opportunities than a regular range, but I'm not sure. */
3179 if (vr->type == VR_ANTI_RANGE)
3182 chrec = instantiate_parameters (loop, analyze_scalar_evolution (loop, var));
3184 /* Like in PR19590, scev can return a constant function. */
3185 if (is_gimple_min_invariant (chrec))
3187 set_value_range_to_value (vr, chrec, vr->equiv);
3191 if (TREE_CODE (chrec) != POLYNOMIAL_CHREC)
3194 init = initial_condition_in_loop_num (chrec, loop->num);
3195 step = evolution_part_in_loop_num (chrec, loop->num);
3197 /* If STEP is symbolic, we can't know whether INIT will be the
3198 minimum or maximum value in the range. Also, unless INIT is
3199 a simple expression, compare_values and possibly other functions
3200 in tree-vrp won't be able to handle it. */
3201 if (step == NULL_TREE
3202 || !is_gimple_min_invariant (step)
3203 || !valid_value_p (init))
3206 dir = scev_direction (chrec);
3207 if (/* Do not adjust ranges if we do not know whether the iv increases
3208 or decreases, ... */
3209 dir == EV_DIR_UNKNOWN
3210 /* ... or if it may wrap. */
3211 || scev_probably_wraps_p (init, step, stmt, get_chrec_loop (chrec),
3215 /* We use TYPE_MIN_VALUE and TYPE_MAX_VALUE here instead of
3216 negative_overflow_infinity and positive_overflow_infinity,
3217 because we have concluded that the loop probably does not
3220 type = TREE_TYPE (var);
3221 if (POINTER_TYPE_P (type) || !TYPE_MIN_VALUE (type))
3222 tmin = lower_bound_in_type (type, type);
3224 tmin = TYPE_MIN_VALUE (type);
3225 if (POINTER_TYPE_P (type) || !TYPE_MAX_VALUE (type))
3226 tmax = upper_bound_in_type (type, type);
3228 tmax = TYPE_MAX_VALUE (type);
3230 if (vr->type == VR_VARYING || vr->type == VR_UNDEFINED)
3235 /* For VARYING or UNDEFINED ranges, just about anything we get
3236 from scalar evolutions should be better. */
3238 if (dir == EV_DIR_DECREASES)
3243 /* If we would create an invalid range, then just assume we
3244 know absolutely nothing. This may be over-conservative,
3245 but it's clearly safe, and should happen only in unreachable
3246 parts of code, or for invalid programs. */
3247 if (compare_values (min, max) == 1)
3250 set_value_range (vr, VR_RANGE, min, max, vr->equiv);
3252 else if (vr->type == VR_RANGE)
3257 if (dir == EV_DIR_DECREASES)
3259 /* INIT is the maximum value. If INIT is lower than VR->MAX
3260 but no smaller than VR->MIN, set VR->MAX to INIT. */
3261 if (compare_values (init, max) == -1)
3265 /* If we just created an invalid range with the minimum
3266 greater than the maximum, we fail conservatively.
3267 This should happen only in unreachable
3268 parts of code, or for invalid programs. */
3269 if (compare_values (min, max) == 1)
3273 /* According to the loop information, the variable does not
3274 overflow. If we think it does, probably because of an
3275 overflow due to arithmetic on a different INF value,
3277 if (is_negative_overflow_infinity (min))
3282 /* If INIT is bigger than VR->MIN, set VR->MIN to INIT. */
3283 if (compare_values (init, min) == 1)
3287 /* Again, avoid creating invalid range by failing. */
3288 if (compare_values (min, max) == 1)
3292 if (is_positive_overflow_infinity (max))
3296 set_value_range (vr, VR_RANGE, min, max, vr->equiv);
3300 /* Return true if VAR may overflow at STMT. This checks any available
3301 loop information to see if we can determine that VAR does not
3305 vrp_var_may_overflow (tree var, gimple stmt)
3308 tree chrec, init, step;
3310 if (current_loops == NULL)
3313 l = loop_containing_stmt (stmt);
3317 chrec = instantiate_parameters (l, analyze_scalar_evolution (l, var));
3318 if (TREE_CODE (chrec) != POLYNOMIAL_CHREC)
3321 init = initial_condition_in_loop_num (chrec, l->num);
3322 step = evolution_part_in_loop_num (chrec, l->num);
3324 if (step == NULL_TREE
3325 || !is_gimple_min_invariant (step)
3326 || !valid_value_p (init))
3329 /* If we get here, we know something useful about VAR based on the
3330 loop information. If it wraps, it may overflow. */
3332 if (scev_probably_wraps_p (init, step, stmt, get_chrec_loop (chrec),
3336 if (dump_file && (dump_flags & TDF_DETAILS) != 0)
3338 print_generic_expr (dump_file, var, 0);
3339 fprintf (dump_file, ": loop information indicates does not overflow\n");
3346 /* Given two numeric value ranges VR0, VR1 and a comparison code COMP:
3348 - Return BOOLEAN_TRUE_NODE if VR0 COMP VR1 always returns true for
3349 all the values in the ranges.
3351 - Return BOOLEAN_FALSE_NODE if the comparison always returns false.
3353 - Return NULL_TREE if it is not always possible to determine the
3354 value of the comparison.
3356 Also set *STRICT_OVERFLOW_P to indicate whether a range with an
3357 overflow infinity was used in the test. */
3361 compare_ranges (enum tree_code comp, value_range_t *vr0, value_range_t *vr1,
3362 bool *strict_overflow_p)
3364 /* VARYING or UNDEFINED ranges cannot be compared. */
3365 if (vr0->type == VR_VARYING
3366 || vr0->type == VR_UNDEFINED
3367 || vr1->type == VR_VARYING
3368 || vr1->type == VR_UNDEFINED)
3371 /* Anti-ranges need to be handled separately. */
3372 if (vr0->type == VR_ANTI_RANGE || vr1->type == VR_ANTI_RANGE)
3374 /* If both are anti-ranges, then we cannot compute any
3376 if (vr0->type == VR_ANTI_RANGE && vr1->type == VR_ANTI_RANGE)
3379 /* These comparisons are never statically computable. */
3386 /* Equality can be computed only between a range and an
3387 anti-range. ~[VAL1, VAL2] == [VAL1, VAL2] is always false. */
3388 if (vr0->type == VR_RANGE)
3390 /* To simplify processing, make VR0 the anti-range. */
3391 value_range_t *tmp = vr0;
3396 gcc_assert (comp == NE_EXPR || comp == EQ_EXPR);
3398 if (compare_values_warnv (vr0->min, vr1->min, strict_overflow_p) == 0
3399 && compare_values_warnv (vr0->max, vr1->max, strict_overflow_p) == 0)
3400 return (comp == NE_EXPR) ? boolean_true_node : boolean_false_node;
3405 if (!usable_range_p (vr0, strict_overflow_p)
3406 || !usable_range_p (vr1, strict_overflow_p))
3409 /* Simplify processing. If COMP is GT_EXPR or GE_EXPR, switch the
3410 operands around and change the comparison code. */
3411 if (comp == GT_EXPR || comp == GE_EXPR)
3414 comp = (comp == GT_EXPR) ? LT_EXPR : LE_EXPR;
3420 if (comp == EQ_EXPR)
3422 /* Equality may only be computed if both ranges represent
3423 exactly one value. */
3424 if (compare_values_warnv (vr0->min, vr0->max, strict_overflow_p) == 0
3425 && compare_values_warnv (vr1->min, vr1->max, strict_overflow_p) == 0)
3427 int cmp_min = compare_values_warnv (vr0->min, vr1->min,
3429 int cmp_max = compare_values_warnv (vr0->max, vr1->max,
3431 if (cmp_min == 0 && cmp_max == 0)
3432 return boolean_true_node;
3433 else if (cmp_min != -2 && cmp_max != -2)
3434 return boolean_false_node;
3436 /* If [V0_MIN, V1_MAX] < [V1_MIN, V1_MAX] then V0 != V1. */
3437 else if (compare_values_warnv (vr0->min, vr1->max,
3438 strict_overflow_p) == 1
3439 || compare_values_warnv (vr1->min, vr0->max,
3440 strict_overflow_p) == 1)
3441 return boolean_false_node;
3445 else if (comp == NE_EXPR)
3449 /* If VR0 is completely to the left or completely to the right
3450 of VR1, they are always different. Notice that we need to
3451 make sure that both comparisons yield similar results to
3452 avoid comparing values that cannot be compared at
3454 cmp1 = compare_values_warnv (vr0->max, vr1->min, strict_overflow_p);
3455 cmp2 = compare_values_warnv (vr0->min, vr1->max, strict_overflow_p);
3456 if ((cmp1 == -1 && cmp2 == -1) || (cmp1 == 1 && cmp2 == 1))
3457 return boolean_true_node;
3459 /* If VR0 and VR1 represent a single value and are identical,
3461 else if (compare_values_warnv (vr0->min, vr0->max,
3462 strict_overflow_p) == 0
3463 && compare_values_warnv (vr1->min, vr1->max,
3464 strict_overflow_p) == 0
3465 && compare_values_warnv (vr0->min, vr1->min,
3466 strict_overflow_p) == 0
3467 && compare_values_warnv (vr0->max, vr1->max,
3468 strict_overflow_p) == 0)
3469 return boolean_false_node;
3471 /* Otherwise, they may or may not be different. */
3475 else if (comp == LT_EXPR || comp == LE_EXPR)
3479 /* If VR0 is to the left of VR1, return true. */
3480 tst = compare_values_warnv (vr0->max, vr1->min, strict_overflow_p);
3481 if ((comp == LT_EXPR && tst == -1)
3482 || (comp == LE_EXPR && (tst == -1 || tst == 0)))
3484 if (overflow_infinity_range_p (vr0)
3485 || overflow_infinity_range_p (vr1))
3486 *strict_overflow_p = true;
3487 return boolean_true_node;
3490 /* If VR0 is to the right of VR1, return false. */
3491 tst = compare_values_warnv (vr0->min, vr1->max, strict_overflow_p);
3492 if ((comp == LT_EXPR && (tst == 0 || tst == 1))
3493 || (comp == LE_EXPR && tst == 1))
3495 if (overflow_infinity_range_p (vr0)
3496 || overflow_infinity_range_p (vr1))
3497 *strict_overflow_p = true;
3498 return boolean_false_node;
3501 /* Otherwise, we don't know. */
3509 /* Given a value range VR, a value VAL and a comparison code COMP, return
3510 BOOLEAN_TRUE_NODE if VR COMP VAL always returns true for all the
3511 values in VR. Return BOOLEAN_FALSE_NODE if the comparison
3512 always returns false. Return NULL_TREE if it is not always
3513 possible to determine the value of the comparison. Also set
3514 *STRICT_OVERFLOW_P to indicate whether a range with an overflow
3515 infinity was used in the test. */
3518 compare_range_with_value (enum tree_code comp, value_range_t *vr, tree val,
3519 bool *strict_overflow_p)
3521 if (vr->type == VR_VARYING || vr->type == VR_UNDEFINED)
3524 /* Anti-ranges need to be handled separately. */
3525 if (vr->type == VR_ANTI_RANGE)
3527 /* For anti-ranges, the only predicates that we can compute at
3528 compile time are equality and inequality. */
3535 /* ~[VAL_1, VAL_2] OP VAL is known if VAL_1 <= VAL <= VAL_2. */
3536 if (value_inside_range (val, vr) == 1)
3537 return (comp == NE_EXPR) ? boolean_true_node : boolean_false_node;
3542 if (!usable_range_p (vr, strict_overflow_p))
3545 if (comp == EQ_EXPR)
3547 /* EQ_EXPR may only be computed if VR represents exactly
3549 if (compare_values_warnv (vr->min, vr->max, strict_overflow_p) == 0)
3551 int cmp = compare_values_warnv (vr->min, val, strict_overflow_p);
3553 return boolean_true_node;
3554 else if (cmp == -1 || cmp == 1 || cmp == 2)
3555 return boolean_false_node;
3557 else if (compare_values_warnv (val, vr->min, strict_overflow_p) == -1
3558 || compare_values_warnv (vr->max, val, strict_overflow_p) == -1)
3559 return boolean_false_node;
3563 else if (comp == NE_EXPR)
3565 /* If VAL is not inside VR, then they are always different. */
3566 if (compare_values_warnv (vr->max, val, strict_overflow_p) == -1
3567 || compare_values_warnv (vr->min, val, strict_overflow_p) == 1)
3568 return boolean_true_node;
3570 /* If VR represents exactly one value equal to VAL, then return
3572 if (compare_values_warnv (vr->min, vr->max, strict_overflow_p) == 0
3573 && compare_values_warnv (vr->min, val, strict_overflow_p) == 0)
3574 return boolean_false_node;
3576 /* Otherwise, they may or may not be different. */
3579 else if (comp == LT_EXPR || comp == LE_EXPR)
3583 /* If VR is to the left of VAL, return true. */
3584 tst = compare_values_warnv (vr->max, val, strict_overflow_p);
3585 if ((comp == LT_EXPR && tst == -1)
3586 || (comp == LE_EXPR && (tst == -1 || tst == 0)))
3588 if (overflow_infinity_range_p (vr))
3589 *strict_overflow_p = true;
3590 return boolean_true_node;
3593 /* If VR is to the right of VAL, return false. */
3594 tst = compare_values_warnv (vr->min, val, strict_overflow_p);
3595 if ((comp == LT_EXPR && (tst == 0 || tst == 1))
3596 || (comp == LE_EXPR && tst == 1))
3598 if (overflow_infinity_range_p (vr))
3599 *strict_overflow_p = true;
3600 return boolean_false_node;
3603 /* Otherwise, we don't know. */
3606 else if (comp == GT_EXPR || comp == GE_EXPR)
3610 /* If VR is to the right of VAL, return true. */
3611 tst = compare_values_warnv (vr->min, val, strict_overflow_p);
3612 if ((comp == GT_EXPR && tst == 1)
3613 || (comp == GE_EXPR && (tst == 0 || tst == 1)))
3615 if (overflow_infinity_range_p (vr))
3616 *strict_overflow_p = true;
3617 return boolean_true_node;
3620 /* If VR is to the left of VAL, return false. */
3621 tst = compare_values_warnv (vr->max, val, strict_overflow_p);
3622 if ((comp == GT_EXPR && (tst == -1 || tst == 0))
3623 || (comp == GE_EXPR && tst == -1))
3625 if (overflow_infinity_range_p (vr))
3626 *strict_overflow_p = true;
3627 return boolean_false_node;
3630 /* Otherwise, we don't know. */
3638 /* Debugging dumps. */
3640 void dump_value_range (FILE *, value_range_t *);
3641 void debug_value_range (value_range_t *);
3642 void dump_all_value_ranges (FILE *);
3643 void debug_all_value_ranges (void);
3644 void dump_vr_equiv (FILE *, bitmap);
3645 void debug_vr_equiv (bitmap);
3648 /* Dump value range VR to FILE. */
3651 dump_value_range (FILE *file, value_range_t *vr)
3654 fprintf (file, "[]");
3655 else if (vr->type == VR_UNDEFINED)
3656 fprintf (file, "UNDEFINED");
3657 else if (vr->type == VR_RANGE || vr->type == VR_ANTI_RANGE)
3659 tree type = TREE_TYPE (vr->min);
3661 fprintf (file, "%s[", (vr->type == VR_ANTI_RANGE) ? "~" : "");
3663 if (is_negative_overflow_infinity (vr->min))
3664 fprintf (file, "-INF(OVF)");
3665 else if (INTEGRAL_TYPE_P (type)
3666 && !TYPE_UNSIGNED (type)
3667 && vrp_val_is_min (vr->min))
3668 fprintf (file, "-INF");
3670 print_generic_expr (file, vr->min, 0);
3672 fprintf (file, ", ");
3674 if (is_positive_overflow_infinity (vr->max))
3675 fprintf (file, "+INF(OVF)");
3676 else if (INTEGRAL_TYPE_P (type)
3677 && vrp_val_is_max (vr->max))
3678 fprintf (file, "+INF");
3680 print_generic_expr (file, vr->max, 0);
3682 fprintf (file, "]");
3689 fprintf (file, " EQUIVALENCES: { ");
3691 EXECUTE_IF_SET_IN_BITMAP (vr->equiv, 0, i, bi)
3693 print_generic_expr (file, ssa_name (i), 0);
3694 fprintf (file, " ");
3698 fprintf (file, "} (%u elements)", c);
3701 else if (vr->type == VR_VARYING)
3702 fprintf (file, "VARYING");
3704 fprintf (file, "INVALID RANGE");
3708 /* Dump value range VR to stderr. */
3711 debug_value_range (value_range_t *vr)
3713 dump_value_range (stderr, vr);
3714 fprintf (stderr, "\n");
3718 /* Dump value ranges of all SSA_NAMEs to FILE. */
3721 dump_all_value_ranges (FILE *file)
3725 for (i = 0; i < num_ssa_names; i++)
3729 print_generic_expr (file, ssa_name (i), 0);
3730 fprintf (file, ": ");
3731 dump_value_range (file, vr_value[i]);
3732 fprintf (file, "\n");
3736 fprintf (file, "\n");
3740 /* Dump all value ranges to stderr. */
3743 debug_all_value_ranges (void)
3745 dump_all_value_ranges (stderr);
3749 /* Given a COND_EXPR COND of the form 'V OP W', and an SSA name V,
3750 create a new SSA name N and return the assertion assignment
3751 'V = ASSERT_EXPR <V, V OP W>'. */
3754 build_assert_expr_for (tree cond, tree v)
3759 gcc_assert (TREE_CODE (v) == SSA_NAME);
3760 n = duplicate_ssa_name (v, NULL);
3762 if (COMPARISON_CLASS_P (cond))
3764 tree a = build2 (ASSERT_EXPR, TREE_TYPE (v), v, cond);
3765 assertion = gimple_build_assign (n, a);
3767 else if (TREE_CODE (cond) == TRUTH_NOT_EXPR)
3769 /* Given !V, build the assignment N = false. */
3770 tree op0 = TREE_OPERAND (cond, 0);
3771 gcc_assert (op0 == v);
3772 assertion = gimple_build_assign (n, boolean_false_node);
3774 else if (TREE_CODE (cond) == SSA_NAME)
3776 /* Given V, build the assignment N = true. */
3777 gcc_assert (v == cond);
3778 assertion = gimple_build_assign (n, boolean_true_node);
3783 SSA_NAME_DEF_STMT (n) = assertion;
3785 /* The new ASSERT_EXPR, creates a new SSA name that replaces the
3786 operand of the ASSERT_EXPR. Register the new name and the old one
3787 in the replacement table so that we can fix the SSA web after
3788 adding all the ASSERT_EXPRs. */
3789 register_new_name_mapping (n, v);
3795 /* Return false if EXPR is a predicate expression involving floating
3799 fp_predicate (gimple stmt)
3801 GIMPLE_CHECK (stmt, GIMPLE_COND);
3803 return FLOAT_TYPE_P (TREE_TYPE (gimple_cond_lhs (stmt)));
3807 /* If the range of values taken by OP can be inferred after STMT executes,
3808 return the comparison code (COMP_CODE_P) and value (VAL_P) that
3809 describes the inferred range. Return true if a range could be
3813 infer_value_range (gimple stmt, tree op, enum tree_code *comp_code_p, tree *val_p)
3816 *comp_code_p = ERROR_MARK;
3818 /* Do not attempt to infer anything in names that flow through
3820 if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (op))
3823 /* Similarly, don't infer anything from statements that may throw
3825 if (stmt_could_throw_p (stmt))
3828 /* If STMT is the last statement of a basic block with no
3829 successors, there is no point inferring anything about any of its
3830 operands. We would not be able to find a proper insertion point
3831 for the assertion, anyway. */
3832 if (stmt_ends_bb_p (stmt) && EDGE_COUNT (gimple_bb (stmt)->succs) == 0)
3835 /* We can only assume that a pointer dereference will yield
3836 non-NULL if -fdelete-null-pointer-checks is enabled. */
3837 if (flag_delete_null_pointer_checks
3838 && POINTER_TYPE_P (TREE_TYPE (op))
3839 && gimple_code (stmt) != GIMPLE_ASM)
3841 unsigned num_uses, num_loads, num_stores;
3843 count_uses_and_derefs (op, stmt, &num_uses, &num_loads, &num_stores);
3844 if (num_loads + num_stores > 0)
3846 *val_p = build_int_cst (TREE_TYPE (op), 0);
3847 *comp_code_p = NE_EXPR;
3856 void dump_asserts_for (FILE *, tree);
3857 void debug_asserts_for (tree);
3858 void dump_all_asserts (FILE *);
3859 void debug_all_asserts (void);
3861 /* Dump all the registered assertions for NAME to FILE. */
3864 dump_asserts_for (FILE *file, tree name)
3868 fprintf (file, "Assertions to be inserted for ");
3869 print_generic_expr (file, name, 0);
3870 fprintf (file, "\n");
3872 loc = asserts_for[SSA_NAME_VERSION (name)];
3875 fprintf (file, "\t");
3876 print_gimple_stmt (file, gsi_stmt (loc->si), 0, 0);
3877 fprintf (file, "\n\tBB #%d", loc->bb->index);
3880 fprintf (file, "\n\tEDGE %d->%d", loc->e->src->index,
3881 loc->e->dest->index);
3882 dump_edge_info (file, loc->e, 0);
3884 fprintf (file, "\n\tPREDICATE: ");
3885 print_generic_expr (file, name, 0);
3886 fprintf (file, " %s ", tree_code_name[(int)loc->comp_code]);
3887 print_generic_expr (file, loc->val, 0);
3888 fprintf (file, "\n\n");
3892 fprintf (file, "\n");
3896 /* Dump all the registered assertions for NAME to stderr. */
3899 debug_asserts_for (tree name)
3901 dump_asserts_for (stderr, name);
3905 /* Dump all the registered assertions for all the names to FILE. */
3908 dump_all_asserts (FILE *file)
3913 fprintf (file, "\nASSERT_EXPRs to be inserted\n\n");
3914 EXECUTE_IF_SET_IN_BITMAP (need_assert_for, 0, i, bi)
3915 dump_asserts_for (file, ssa_name (i));
3916 fprintf (file, "\n");
3920 /* Dump all the registered assertions for all the names to stderr. */
3923 debug_all_asserts (void)
3925 dump_all_asserts (stderr);
3929 /* If NAME doesn't have an ASSERT_EXPR registered for asserting
3930 'EXPR COMP_CODE VAL' at a location that dominates block BB or
3931 E->DEST, then register this location as a possible insertion point
3932 for ASSERT_EXPR <NAME, EXPR COMP_CODE VAL>.
3934 BB, E and SI provide the exact insertion point for the new
3935 ASSERT_EXPR. If BB is NULL, then the ASSERT_EXPR is to be inserted
3936 on edge E. Otherwise, if E is NULL, the ASSERT_EXPR is inserted on
3937 BB. If SI points to a COND_EXPR or a SWITCH_EXPR statement, then E
3938 must not be NULL. */
3941 register_new_assert_for (tree name, tree expr,
3942 enum tree_code comp_code,
3946 gimple_stmt_iterator si)
3948 assert_locus_t n, loc, last_loc;
3950 basic_block dest_bb;
3952 #if defined ENABLE_CHECKING
3953 gcc_assert (bb == NULL || e == NULL);
3956 gcc_assert (gimple_code (gsi_stmt (si)) != GIMPLE_COND
3957 && gimple_code (gsi_stmt (si)) != GIMPLE_SWITCH);
3960 /* Never build an assert comparing against an integer constant with
3961 TREE_OVERFLOW set. This confuses our undefined overflow warning
3963 if (TREE_CODE (val) == INTEGER_CST
3964 && TREE_OVERFLOW (val))
3965 val = build_int_cst_wide (TREE_TYPE (val),
3966 TREE_INT_CST_LOW (val), TREE_INT_CST_HIGH (val));
3968 /* The new assertion A will be inserted at BB or E. We need to
3969 determine if the new location is dominated by a previously
3970 registered location for A. If we are doing an edge insertion,
3971 assume that A will be inserted at E->DEST. Note that this is not
3974 If E is a critical edge, it will be split. But even if E is
3975 split, the new block will dominate the same set of blocks that
3978 The reverse, however, is not true, blocks dominated by E->DEST
3979 will not be dominated by the new block created to split E. So,
3980 if the insertion location is on a critical edge, we will not use
3981 the new location to move another assertion previously registered
3982 at a block dominated by E->DEST. */
3983 dest_bb = (bb) ? bb : e->dest;
3985 /* If NAME already has an ASSERT_EXPR registered for COMP_CODE and
3986 VAL at a block dominating DEST_BB, then we don't need to insert a new
3987 one. Similarly, if the same assertion already exists at a block
3988 dominated by DEST_BB and the new location is not on a critical
3989 edge, then update the existing location for the assertion (i.e.,
3990 move the assertion up in the dominance tree).
3992 Note, this is implemented as a simple linked list because there
3993 should not be more than a handful of assertions registered per
3994 name. If this becomes a performance problem, a table hashed by
3995 COMP_CODE and VAL could be implemented. */
3996 loc = asserts_for[SSA_NAME_VERSION (name)];
4001 if (loc->comp_code == comp_code
4003 || operand_equal_p (loc->val, val, 0))
4004 && (loc->expr == expr
4005 || operand_equal_p (loc->expr, expr, 0)))
4007 /* If the assertion NAME COMP_CODE VAL has already been
4008 registered at a basic block that dominates DEST_BB, then
4009 we don't need to insert the same assertion again. Note
4010 that we don't check strict dominance here to avoid
4011 replicating the same assertion inside the same basic
4012 block more than once (e.g., when a pointer is
4013 dereferenced several times inside a block).
4015 An exception to this rule are edge insertions. If the
4016 new assertion is to be inserted on edge E, then it will
4017 dominate all the other insertions that we may want to
4018 insert in DEST_BB. So, if we are doing an edge
4019 insertion, don't do this dominance check. */
4021 && dominated_by_p (CDI_DOMINATORS, dest_bb, loc->bb))
4024 /* Otherwise, if E is not a critical edge and DEST_BB
4025 dominates the existing location for the assertion, move
4026 the assertion up in the dominance tree by updating its
4027 location information. */
4028 if ((e == NULL || !EDGE_CRITICAL_P (e))
4029 && dominated_by_p (CDI_DOMINATORS, loc->bb, dest_bb))
4038 /* Update the last node of the list and move to the next one. */
4043 /* If we didn't find an assertion already registered for
4044 NAME COMP_CODE VAL, add a new one at the end of the list of
4045 assertions associated with NAME. */
4046 n = XNEW (struct assert_locus_d);
4050 n->comp_code = comp_code;
4058 asserts_for[SSA_NAME_VERSION (name)] = n;
4060 bitmap_set_bit (need_assert_for, SSA_NAME_VERSION (name));
4063 /* (COND_OP0 COND_CODE COND_OP1) is a predicate which uses NAME.
4064 Extract a suitable test code and value and store them into *CODE_P and
4065 *VAL_P so the predicate is normalized to NAME *CODE_P *VAL_P.
4067 If no extraction was possible, return FALSE, otherwise return TRUE.
4069 If INVERT is true, then we invert the result stored into *CODE_P. */
4072 extract_code_and_val_from_cond_with_ops (tree name, enum tree_code cond_code,
4073 tree cond_op0, tree cond_op1,
4074 bool invert, enum tree_code *code_p,
4077 enum tree_code comp_code;
4080 /* Otherwise, we have a comparison of the form NAME COMP VAL
4081 or VAL COMP NAME. */
4082 if (name == cond_op1)
4084 /* If the predicate is of the form VAL COMP NAME, flip
4085 COMP around because we need to register NAME as the
4086 first operand in the predicate. */
4087 comp_code = swap_tree_comparison (cond_code);
4092 /* The comparison is of the form NAME COMP VAL, so the
4093 comparison code remains unchanged. */
4094 comp_code = cond_code;
4098 /* Invert the comparison code as necessary. */
4100 comp_code = invert_tree_comparison (comp_code, 0);
4102 /* VRP does not handle float types. */
4103 if (SCALAR_FLOAT_TYPE_P (TREE_TYPE (val)))
4106 /* Do not register always-false predicates.
4107 FIXME: this works around a limitation in fold() when dealing with
4108 enumerations. Given 'enum { N1, N2 } x;', fold will not
4109 fold 'if (x > N2)' to 'if (0)'. */
4110 if ((comp_code == GT_EXPR || comp_code == LT_EXPR)
4111 && INTEGRAL_TYPE_P (TREE_TYPE (val)))
4113 tree min = TYPE_MIN_VALUE (TREE_TYPE (val));
4114 tree max = TYPE_MAX_VALUE (TREE_TYPE (val));
4116 if (comp_code == GT_EXPR
4118 || compare_values (val, max) == 0))
4121 if (comp_code == LT_EXPR
4123 || compare_values (val, min) == 0))
4126 *code_p = comp_code;
4131 /* Try to register an edge assertion for SSA name NAME on edge E for
4132 the condition COND contributing to the conditional jump pointed to by BSI.
4133 Invert the condition COND if INVERT is true.
4134 Return true if an assertion for NAME could be registered. */
4137 register_edge_assert_for_2 (tree name, edge e, gimple_stmt_iterator bsi,
4138 enum tree_code cond_code,
4139 tree cond_op0, tree cond_op1, bool invert)
4142 enum tree_code comp_code;
4143 bool retval = false;
4145 if (!extract_code_and_val_from_cond_with_ops (name, cond_code,
4148 invert, &comp_code, &val))
4151 /* Only register an ASSERT_EXPR if NAME was found in the sub-graph
4152 reachable from E. */
4153 if (live_on_edge (e, name)
4154 && !has_single_use (name))
4156 register_new_assert_for (name, name, comp_code, val, NULL, e, bsi);
4160 /* In the case of NAME <= CST and NAME being defined as
4161 NAME = (unsigned) NAME2 + CST2 we can assert NAME2 >= -CST2
4162 and NAME2 <= CST - CST2. We can do the same for NAME > CST.
4163 This catches range and anti-range tests. */
4164 if ((comp_code == LE_EXPR
4165 || comp_code == GT_EXPR)
4166 && TREE_CODE (val) == INTEGER_CST
4167 && TYPE_UNSIGNED (TREE_TYPE (val)))
4169 gimple def_stmt = SSA_NAME_DEF_STMT (name);
4170 tree cst2 = NULL_TREE, name2 = NULL_TREE, name3 = NULL_TREE;
4172 /* Extract CST2 from the (optional) addition. */
4173 if (is_gimple_assign (def_stmt)
4174 && gimple_assign_rhs_code (def_stmt) == PLUS_EXPR)
4176 name2 = gimple_assign_rhs1 (def_stmt);
4177 cst2 = gimple_assign_rhs2 (def_stmt);
4178 if (TREE_CODE (name2) == SSA_NAME
4179 && TREE_CODE (cst2) == INTEGER_CST)
4180 def_stmt = SSA_NAME_DEF_STMT (name2);
4183 /* Extract NAME2 from the (optional) sign-changing cast. */
4184 if (gimple_assign_cast_p (def_stmt))
4186 if (CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (def_stmt))
4187 && ! TYPE_UNSIGNED (TREE_TYPE (gimple_assign_rhs1 (def_stmt)))
4188 && (TYPE_PRECISION (gimple_expr_type (def_stmt))
4189 == TYPE_PRECISION (TREE_TYPE (gimple_assign_rhs1 (def_stmt)))))
4190 name3 = gimple_assign_rhs1 (def_stmt);
4193 /* If name3 is used later, create an ASSERT_EXPR for it. */
4194 if (name3 != NULL_TREE
4195 && TREE_CODE (name3) == SSA_NAME
4196 && (cst2 == NULL_TREE
4197 || TREE_CODE (cst2) == INTEGER_CST)
4198 && INTEGRAL_TYPE_P (TREE_TYPE (name3))
4199 && live_on_edge (e, name3)
4200 && !has_single_use (name3))
4204 /* Build an expression for the range test. */
4205 tmp = build1 (NOP_EXPR, TREE_TYPE (name), name3);
4206 if (cst2 != NULL_TREE)
4207 tmp = build2 (PLUS_EXPR, TREE_TYPE (name), tmp, cst2);
4211 fprintf (dump_file, "Adding assert for ");
4212 print_generic_expr (dump_file, name3, 0);
4213 fprintf (dump_file, " from ");
4214 print_generic_expr (dump_file, tmp, 0);
4215 fprintf (dump_file, "\n");
4218 register_new_assert_for (name3, tmp, comp_code, val, NULL, e, bsi);
4223 /* If name2 is used later, create an ASSERT_EXPR for it. */
4224 if (name2 != NULL_TREE
4225 && TREE_CODE (name2) == SSA_NAME
4226 && TREE_CODE (cst2) == INTEGER_CST
4227 && INTEGRAL_TYPE_P (TREE_TYPE (name2))
4228 && live_on_edge (e, name2)
4229 && !has_single_use (name2))
4233 /* Build an expression for the range test. */
4235 if (TREE_TYPE (name) != TREE_TYPE (name2))
4236 tmp = build1 (NOP_EXPR, TREE_TYPE (name), tmp);
4237 if (cst2 != NULL_TREE)
4238 tmp = build2 (PLUS_EXPR, TREE_TYPE (name), tmp, cst2);
4242 fprintf (dump_file, "Adding assert for ");
4243 print_generic_expr (dump_file, name2, 0);
4244 fprintf (dump_file, " from ");
4245 print_generic_expr (dump_file, tmp, 0);
4246 fprintf (dump_file, "\n");
4249 register_new_assert_for (name2, tmp, comp_code, val, NULL, e, bsi);
4258 /* OP is an operand of a truth value expression which is known to have
4259 a particular value. Register any asserts for OP and for any
4260 operands in OP's defining statement.
4262 If CODE is EQ_EXPR, then we want to register OP is zero (false),
4263 if CODE is NE_EXPR, then we want to register OP is nonzero (true). */
4266 register_edge_assert_for_1 (tree op, enum tree_code code,
4267 edge e, gimple_stmt_iterator bsi)
4269 bool retval = false;
4272 enum tree_code rhs_code;
4274 /* We only care about SSA_NAMEs. */
4275 if (TREE_CODE (op) != SSA_NAME)
4278 /* We know that OP will have a zero or nonzero value. If OP is used
4279 more than once go ahead and register an assert for OP.
4281 The FOUND_IN_SUBGRAPH support is not helpful in this situation as
4282 it will always be set for OP (because OP is used in a COND_EXPR in
4284 if (!has_single_use (op))
4286 val = build_int_cst (TREE_TYPE (op), 0);
4287 register_new_assert_for (op, op, code, val, NULL, e, bsi);
4291 /* Now look at how OP is set. If it's set from a comparison,
4292 a truth operation or some bit operations, then we may be able
4293 to register information about the operands of that assignment. */
4294 op_def = SSA_NAME_DEF_STMT (op);
4295 if (gimple_code (op_def) != GIMPLE_ASSIGN)
4298 rhs_code = gimple_assign_rhs_code (op_def);
4300 if (TREE_CODE_CLASS (rhs_code) == tcc_comparison)
4302 bool invert = (code == EQ_EXPR ? true : false);
4303 tree op0 = gimple_assign_rhs1 (op_def);
4304 tree op1 = gimple_assign_rhs2 (op_def);
4306 if (TREE_CODE (op0) == SSA_NAME)
4307 retval |= register_edge_assert_for_2 (op0, e, bsi, rhs_code, op0, op1,
4309 if (TREE_CODE (op1) == SSA_NAME)
4310 retval |= register_edge_assert_for_2 (op1, e, bsi, rhs_code, op0, op1,
4313 else if ((code == NE_EXPR
4314 && (gimple_assign_rhs_code (op_def) == TRUTH_AND_EXPR
4315 || gimple_assign_rhs_code (op_def) == BIT_AND_EXPR))
4317 && (gimple_assign_rhs_code (op_def) == TRUTH_OR_EXPR
4318 || gimple_assign_rhs_code (op_def) == BIT_IOR_EXPR)))
4320 /* Recurse on each operand. */
4321 retval |= register_edge_assert_for_1 (gimple_assign_rhs1 (op_def),
4323 retval |= register_edge_assert_for_1 (gimple_assign_rhs2 (op_def),
4326 else if (gimple_assign_rhs_code (op_def) == TRUTH_NOT_EXPR)
4328 /* Recurse, flipping CODE. */
4329 code = invert_tree_comparison (code, false);
4330 retval |= register_edge_assert_for_1 (gimple_assign_rhs1 (op_def),
4333 else if (gimple_assign_rhs_code (op_def) == SSA_NAME)
4335 /* Recurse through the copy. */
4336 retval |= register_edge_assert_for_1 (gimple_assign_rhs1 (op_def),
4339 else if (CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (op_def)))
4341 /* Recurse through the type conversion. */
4342 retval |= register_edge_assert_for_1 (gimple_assign_rhs1 (op_def),
4349 /* Try to register an edge assertion for SSA name NAME on edge E for
4350 the condition COND contributing to the conditional jump pointed to by SI.
4351 Return true if an assertion for NAME could be registered. */
4354 register_edge_assert_for (tree name, edge e, gimple_stmt_iterator si,
4355 enum tree_code cond_code, tree cond_op0,
4359 enum tree_code comp_code;
4360 bool retval = false;
4361 bool is_else_edge = (e->flags & EDGE_FALSE_VALUE) != 0;
4363 /* Do not attempt to infer anything in names that flow through
4365 if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (name))
4368 if (!extract_code_and_val_from_cond_with_ops (name, cond_code,
4374 /* Register ASSERT_EXPRs for name. */
4375 retval |= register_edge_assert_for_2 (name, e, si, cond_code, cond_op0,
4376 cond_op1, is_else_edge);
4379 /* If COND is effectively an equality test of an SSA_NAME against
4380 the value zero or one, then we may be able to assert values
4381 for SSA_NAMEs which flow into COND. */
4383 /* In the case of NAME == 1 or NAME != 0, for TRUTH_AND_EXPR defining
4384 statement of NAME we can assert both operands of the TRUTH_AND_EXPR
4385 have nonzero value. */
4386 if (((comp_code == EQ_EXPR && integer_onep (val))
4387 || (comp_code == NE_EXPR && integer_zerop (val))))
4389 gimple def_stmt = SSA_NAME_DEF_STMT (name);
4391 if (is_gimple_assign (def_stmt)
4392 && (gimple_assign_rhs_code (def_stmt) == TRUTH_AND_EXPR
4393 || gimple_assign_rhs_code (def_stmt) == BIT_AND_EXPR))
4395 tree op0 = gimple_assign_rhs1 (def_stmt);
4396 tree op1 = gimple_assign_rhs2 (def_stmt);
4397 retval |= register_edge_assert_for_1 (op0, NE_EXPR, e, si);
4398 retval |= register_edge_assert_for_1 (op1, NE_EXPR, e, si);
4402 /* In the case of NAME == 0 or NAME != 1, for TRUTH_OR_EXPR defining
4403 statement of NAME we can assert both operands of the TRUTH_OR_EXPR
4405 if (((comp_code == EQ_EXPR && integer_zerop (val))
4406 || (comp_code == NE_EXPR && integer_onep (val))))
4408 gimple def_stmt = SSA_NAME_DEF_STMT (name);
4410 if (is_gimple_assign (def_stmt)
4411 && (gimple_assign_rhs_code (def_stmt) == TRUTH_OR_EXPR
4412 /* For BIT_IOR_EXPR only if NAME == 0 both operands have
4413 necessarily zero value. */
4414 || (comp_code == EQ_EXPR
4415 && (gimple_assign_rhs_code (def_stmt) == BIT_IOR_EXPR))))
4417 tree op0 = gimple_assign_rhs1 (def_stmt);
4418 tree op1 = gimple_assign_rhs2 (def_stmt);
4419 retval |= register_edge_assert_for_1 (op0, EQ_EXPR, e, si);
4420 retval |= register_edge_assert_for_1 (op1, EQ_EXPR, e, si);
4428 /* Determine whether the outgoing edges of BB should receive an
4429 ASSERT_EXPR for each of the operands of BB's LAST statement.
4430 The last statement of BB must be a COND_EXPR.
4432 If any of the sub-graphs rooted at BB have an interesting use of
4433 the predicate operands, an assert location node is added to the
4434 list of assertions for the corresponding operands. */
4437 find_conditional_asserts (basic_block bb, gimple last)
4440 gimple_stmt_iterator bsi;
4446 need_assert = false;
4447 bsi = gsi_for_stmt (last);
4449 /* Look for uses of the operands in each of the sub-graphs
4450 rooted at BB. We need to check each of the outgoing edges
4451 separately, so that we know what kind of ASSERT_EXPR to
4453 FOR_EACH_EDGE (e, ei, bb->succs)
4458 /* Register the necessary assertions for each operand in the
4459 conditional predicate. */
4460 FOR_EACH_SSA_TREE_OPERAND (op, last, iter, SSA_OP_USE)
4462 need_assert |= register_edge_assert_for (op, e, bsi,
4463 gimple_cond_code (last),
4464 gimple_cond_lhs (last),
4465 gimple_cond_rhs (last));
4472 /* Compare two case labels sorting first by the destination label uid
4473 and then by the case value. */
4476 compare_case_labels (const void *p1, const void *p2)
4478 const_tree const case1 = *(const_tree const*)p1;
4479 const_tree const case2 = *(const_tree const*)p2;
4480 unsigned int uid1 = DECL_UID (CASE_LABEL (case1));
4481 unsigned int uid2 = DECL_UID (CASE_LABEL (case2));
4485 else if (uid1 == uid2)
4487 /* Make sure the default label is first in a group. */
4488 if (!CASE_LOW (case1))
4490 else if (!CASE_LOW (case2))
4493 return tree_int_cst_compare (CASE_LOW (case1), CASE_LOW (case2));
4499 /* Determine whether the outgoing edges of BB should receive an
4500 ASSERT_EXPR for each of the operands of BB's LAST statement.
4501 The last statement of BB must be a SWITCH_EXPR.
4503 If any of the sub-graphs rooted at BB have an interesting use of
4504 the predicate operands, an assert location node is added to the
4505 list of assertions for the corresponding operands. */
4508 find_switch_asserts (basic_block bb, gimple last)
4511 gimple_stmt_iterator bsi;
4515 size_t n = gimple_switch_num_labels(last);
4516 #if GCC_VERSION >= 4000
4519 /* Work around GCC 3.4 bug (PR 37086). */
4520 volatile unsigned int idx;
4523 need_assert = false;
4524 bsi = gsi_for_stmt (last);
4525 op = gimple_switch_index (last);
4526 if (TREE_CODE (op) != SSA_NAME)
4529 /* Build a vector of case labels sorted by destination label. */
4530 vec2 = make_tree_vec (n);
4531 for (idx = 0; idx < n; ++idx)
4532 TREE_VEC_ELT (vec2, idx) = gimple_switch_label (last, idx);
4533 qsort (&TREE_VEC_ELT (vec2, 0), n, sizeof (tree), compare_case_labels);
4535 for (idx = 0; idx < n; ++idx)
4538 tree cl = TREE_VEC_ELT (vec2, idx);
4540 min = CASE_LOW (cl);
4541 max = CASE_HIGH (cl);
4543 /* If there are multiple case labels with the same destination
4544 we need to combine them to a single value range for the edge. */
4546 && CASE_LABEL (cl) == CASE_LABEL (TREE_VEC_ELT (vec2, idx + 1)))
4548 /* Skip labels until the last of the group. */
4552 && CASE_LABEL (cl) == CASE_LABEL (TREE_VEC_ELT (vec2, idx)));
4555 /* Pick up the maximum of the case label range. */
4556 if (CASE_HIGH (TREE_VEC_ELT (vec2, idx)))
4557 max = CASE_HIGH (TREE_VEC_ELT (vec2, idx));
4559 max = CASE_LOW (TREE_VEC_ELT (vec2, idx));
4562 /* Nothing to do if the range includes the default label until we
4563 can register anti-ranges. */
4564 if (min == NULL_TREE)
4567 /* Find the edge to register the assert expr on. */
4568 e = find_edge (bb, label_to_block (CASE_LABEL (cl)));
4570 /* Register the necessary assertions for the operand in the
4572 need_assert |= register_edge_assert_for (op, e, bsi,
4573 max ? GE_EXPR : EQ_EXPR,
4575 fold_convert (TREE_TYPE (op),
4579 need_assert |= register_edge_assert_for (op, e, bsi, LE_EXPR,
4581 fold_convert (TREE_TYPE (op),
4590 /* Traverse all the statements in block BB looking for statements that
4591 may generate useful assertions for the SSA names in their operand.
4592 If a statement produces a useful assertion A for name N_i, then the
4593 list of assertions already generated for N_i is scanned to
4594 determine if A is actually needed.
4596 If N_i already had the assertion A at a location dominating the
4597 current location, then nothing needs to be done. Otherwise, the
4598 new location for A is recorded instead.
4600 1- For every statement S in BB, all the variables used by S are
4601 added to bitmap FOUND_IN_SUBGRAPH.
4603 2- If statement S uses an operand N in a way that exposes a known
4604 value range for N, then if N was not already generated by an
4605 ASSERT_EXPR, create a new assert location for N. For instance,
4606 if N is a pointer and the statement dereferences it, we can
4607 assume that N is not NULL.
4609 3- COND_EXPRs are a special case of #2. We can derive range
4610 information from the predicate but need to insert different
4611 ASSERT_EXPRs for each of the sub-graphs rooted at the
4612 conditional block. If the last statement of BB is a conditional
4613 expression of the form 'X op Y', then
4615 a) Remove X and Y from the set FOUND_IN_SUBGRAPH.
4617 b) If the conditional is the only entry point to the sub-graph
4618 corresponding to the THEN_CLAUSE, recurse into it. On
4619 return, if X and/or Y are marked in FOUND_IN_SUBGRAPH, then
4620 an ASSERT_EXPR is added for the corresponding variable.
4622 c) Repeat step (b) on the ELSE_CLAUSE.
4624 d) Mark X and Y in FOUND_IN_SUBGRAPH.
4633 In this case, an assertion on the THEN clause is useful to
4634 determine that 'a' is always 9 on that edge. However, an assertion
4635 on the ELSE clause would be unnecessary.
4637 4- If BB does not end in a conditional expression, then we recurse
4638 into BB's dominator children.
4640 At the end of the recursive traversal, every SSA name will have a
4641 list of locations where ASSERT_EXPRs should be added. When a new
4642 location for name N is found, it is registered by calling
4643 register_new_assert_for. That function keeps track of all the
4644 registered assertions to prevent adding unnecessary assertions.
4645 For instance, if a pointer P_4 is dereferenced more than once in a
4646 dominator tree, only the location dominating all the dereference of
4647 P_4 will receive an ASSERT_EXPR.
4649 If this function returns true, then it means that there are names
4650 for which we need to generate ASSERT_EXPRs. Those assertions are
4651 inserted by process_assert_insertions. */
4654 find_assert_locations_1 (basic_block bb, sbitmap live)
4656 gimple_stmt_iterator si;
4661 need_assert = false;
4662 last = last_stmt (bb);
4664 /* If BB's last statement is a conditional statement involving integer
4665 operands, determine if we need to add ASSERT_EXPRs. */
4667 && gimple_code (last) == GIMPLE_COND
4668 && !fp_predicate (last)
4669 && !ZERO_SSA_OPERANDS (last, SSA_OP_USE))
4670 need_assert |= find_conditional_asserts (bb, last);
4672 /* If BB's last statement is a switch statement involving integer
4673 operands, determine if we need to add ASSERT_EXPRs. */
4675 && gimple_code (last) == GIMPLE_SWITCH
4676 && !ZERO_SSA_OPERANDS (last, SSA_OP_USE))
4677 need_assert |= find_switch_asserts (bb, last);
4679 /* Traverse all the statements in BB marking used names and looking
4680 for statements that may infer assertions for their used operands. */
4681 for (si = gsi_start_bb (bb); !gsi_end_p (si); gsi_next (&si))
4687 stmt = gsi_stmt (si);
4689 /* See if we can derive an assertion for any of STMT's operands. */
4690 FOR_EACH_SSA_TREE_OPERAND (op, stmt, i, SSA_OP_USE)
4693 enum tree_code comp_code;
4695 /* Mark OP in our live bitmap. */
4696 SET_BIT (live, SSA_NAME_VERSION (op));
4698 /* If OP is used in such a way that we can infer a value
4699 range for it, and we don't find a previous assertion for
4700 it, create a new assertion location node for OP. */
4701 if (infer_value_range (stmt, op, &comp_code, &value))
4703 /* If we are able to infer a nonzero value range for OP,
4704 then walk backwards through the use-def chain to see if OP
4705 was set via a typecast.
4707 If so, then we can also infer a nonzero value range
4708 for the operand of the NOP_EXPR. */
4709 if (comp_code == NE_EXPR && integer_zerop (value))
4712 gimple def_stmt = SSA_NAME_DEF_STMT (t);
4714 while (is_gimple_assign (def_stmt)
4715 && gimple_assign_rhs_code (def_stmt) == NOP_EXPR
4717 (gimple_assign_rhs1 (def_stmt)) == SSA_NAME
4719 (TREE_TYPE (gimple_assign_rhs1 (def_stmt))))
4721 t = gimple_assign_rhs1 (def_stmt);
4722 def_stmt = SSA_NAME_DEF_STMT (t);
4724 /* Note we want to register the assert for the
4725 operand of the NOP_EXPR after SI, not after the
4727 if (! has_single_use (t))
4729 register_new_assert_for (t, t, comp_code, value,
4736 /* If OP is used only once, namely in this STMT, don't
4737 bother creating an ASSERT_EXPR for it. Such an
4738 ASSERT_EXPR would do nothing but increase compile time. */
4739 if (!has_single_use (op))
4741 register_new_assert_for (op, op, comp_code, value,
4749 /* Traverse all PHI nodes in BB marking used operands. */
4750 for (si = gsi_start_phis (bb); !gsi_end_p(si); gsi_next (&si))
4752 use_operand_p arg_p;
4754 phi = gsi_stmt (si);
4756 FOR_EACH_PHI_ARG (arg_p, phi, i, SSA_OP_USE)
4758 tree arg = USE_FROM_PTR (arg_p);
4759 if (TREE_CODE (arg) == SSA_NAME)
4760 SET_BIT (live, SSA_NAME_VERSION (arg));
4767 /* Do an RPO walk over the function computing SSA name liveness
4768 on-the-fly and deciding on assert expressions to insert.
4769 Returns true if there are assert expressions to be inserted. */
4772 find_assert_locations (void)
4774 int *rpo = XCNEWVEC (int, last_basic_block + NUM_FIXED_BLOCKS);
4775 int *bb_rpo = XCNEWVEC (int, last_basic_block + NUM_FIXED_BLOCKS);
4776 int *last_rpo = XCNEWVEC (int, last_basic_block + NUM_FIXED_BLOCKS);
4780 live = XCNEWVEC (sbitmap, last_basic_block + NUM_FIXED_BLOCKS);
4781 rpo_cnt = pre_and_rev_post_order_compute (NULL, rpo, false);
4782 for (i = 0; i < rpo_cnt; ++i)
4785 need_asserts = false;
4786 for (i = rpo_cnt-1; i >= 0; --i)
4788 basic_block bb = BASIC_BLOCK (rpo[i]);
4794 live[rpo[i]] = sbitmap_alloc (num_ssa_names);
4795 sbitmap_zero (live[rpo[i]]);
4798 /* Process BB and update the live information with uses in
4800 need_asserts |= find_assert_locations_1 (bb, live[rpo[i]]);
4802 /* Merge liveness into the predecessor blocks and free it. */
4803 if (!sbitmap_empty_p (live[rpo[i]]))
4806 FOR_EACH_EDGE (e, ei, bb->preds)
4808 int pred = e->src->index;
4809 if (e->flags & EDGE_DFS_BACK)
4814 live[pred] = sbitmap_alloc (num_ssa_names);
4815 sbitmap_zero (live[pred]);
4817 sbitmap_a_or_b (live[pred], live[pred], live[rpo[i]]);
4819 if (bb_rpo[pred] < pred_rpo)
4820 pred_rpo = bb_rpo[pred];
4823 /* Record the RPO number of the last visited block that needs
4824 live information from this block. */
4825 last_rpo[rpo[i]] = pred_rpo;
4829 sbitmap_free (live[rpo[i]]);
4830 live[rpo[i]] = NULL;
4833 /* We can free all successors live bitmaps if all their
4834 predecessors have been visited already. */
4835 FOR_EACH_EDGE (e, ei, bb->succs)
4836 if (last_rpo[e->dest->index] == i
4837 && live[e->dest->index])
4839 sbitmap_free (live[e->dest->index]);
4840 live[e->dest->index] = NULL;
4845 XDELETEVEC (bb_rpo);
4846 XDELETEVEC (last_rpo);
4847 for (i = 0; i < last_basic_block + NUM_FIXED_BLOCKS; ++i)
4849 sbitmap_free (live[i]);
4852 return need_asserts;
4855 /* Create an ASSERT_EXPR for NAME and insert it in the location
4856 indicated by LOC. Return true if we made any edge insertions. */
4859 process_assert_insertions_for (tree name, assert_locus_t loc)
4861 /* Build the comparison expression NAME_i COMP_CODE VAL. */
4868 cond = build2 (loc->comp_code, boolean_type_node, loc->expr, loc->val);
4869 assert_stmt = build_assert_expr_for (cond, name);
4872 /* We have been asked to insert the assertion on an edge. This
4873 is used only by COND_EXPR and SWITCH_EXPR assertions. */
4874 #if defined ENABLE_CHECKING
4875 gcc_assert (gimple_code (gsi_stmt (loc->si)) == GIMPLE_COND
4876 || gimple_code (gsi_stmt (loc->si)) == GIMPLE_SWITCH);
4879 gsi_insert_on_edge (loc->e, assert_stmt);
4883 /* Otherwise, we can insert right after LOC->SI iff the
4884 statement must not be the last statement in the block. */
4885 stmt = gsi_stmt (loc->si);
4886 if (!stmt_ends_bb_p (stmt))
4888 gsi_insert_after (&loc->si, assert_stmt, GSI_SAME_STMT);
4892 /* If STMT must be the last statement in BB, we can only insert new
4893 assertions on the non-abnormal edge out of BB. Note that since
4894 STMT is not control flow, there may only be one non-abnormal edge
4896 FOR_EACH_EDGE (e, ei, loc->bb->succs)
4897 if (!(e->flags & EDGE_ABNORMAL))
4899 gsi_insert_on_edge (e, assert_stmt);
4907 /* Process all the insertions registered for every name N_i registered
4908 in NEED_ASSERT_FOR. The list of assertions to be inserted are
4909 found in ASSERTS_FOR[i]. */
4912 process_assert_insertions (void)
4916 bool update_edges_p = false;
4917 int num_asserts = 0;
4919 if (dump_file && (dump_flags & TDF_DETAILS))
4920 dump_all_asserts (dump_file);
4922 EXECUTE_IF_SET_IN_BITMAP (need_assert_for, 0, i, bi)
4924 assert_locus_t loc = asserts_for[i];
4929 assert_locus_t next = loc->next;
4930 update_edges_p |= process_assert_insertions_for (ssa_name (i), loc);
4938 gsi_commit_edge_inserts ();
4940 statistics_counter_event (cfun, "Number of ASSERT_EXPR expressions inserted",
4945 /* Traverse the flowgraph looking for conditional jumps to insert range
4946 expressions. These range expressions are meant to provide information
4947 to optimizations that need to reason in terms of value ranges. They
4948 will not be expanded into RTL. For instance, given:
4957 this pass will transform the code into:
4963 x = ASSERT_EXPR <x, x < y>
4968 y = ASSERT_EXPR <y, x <= y>
4972 The idea is that once copy and constant propagation have run, other
4973 optimizations will be able to determine what ranges of values can 'x'
4974 take in different paths of the code, simply by checking the reaching
4975 definition of 'x'. */
4978 insert_range_assertions (void)
4980 need_assert_for = BITMAP_ALLOC (NULL);
4981 asserts_for = XCNEWVEC (assert_locus_t, num_ssa_names);
4983 calculate_dominance_info (CDI_DOMINATORS);
4985 if (find_assert_locations ())
4987 process_assert_insertions ();
4988 update_ssa (TODO_update_ssa_no_phi);
4991 if (dump_file && (dump_flags & TDF_DETAILS))
4993 fprintf (dump_file, "\nSSA form after inserting ASSERT_EXPRs\n");
4994 dump_function_to_file (current_function_decl, dump_file, dump_flags);
4998 BITMAP_FREE (need_assert_for);
5001 /* Checks one ARRAY_REF in REF, located at LOCUS. Ignores flexible arrays
5002 and "struct" hacks. If VRP can determine that the
5003 array subscript is a constant, check if it is outside valid
5004 range. If the array subscript is a RANGE, warn if it is
5005 non-overlapping with valid range.
5006 IGNORE_OFF_BY_ONE is true if the ARRAY_REF is inside a ADDR_EXPR. */
5009 check_array_ref (tree ref, const location_t *location, bool ignore_off_by_one)
5011 value_range_t* vr = NULL;
5012 tree low_sub, up_sub;
5013 tree low_bound, up_bound = array_ref_up_bound (ref);
5015 low_sub = up_sub = TREE_OPERAND (ref, 1);
5017 if (!up_bound || TREE_NO_WARNING (ref)
5018 || TREE_CODE (up_bound) != INTEGER_CST
5019 /* Can not check flexible arrays. */
5020 || (TYPE_SIZE (TREE_TYPE (ref)) == NULL_TREE
5021 && TYPE_DOMAIN (TREE_TYPE (ref)) != NULL_TREE
5022 && TYPE_MAX_VALUE (TYPE_DOMAIN (TREE_TYPE (ref))) == NULL_TREE)
5023 /* Accesses after the end of arrays of size 0 (gcc
5024 extension) and 1 are likely intentional ("struct
5026 || compare_tree_int (up_bound, 1) <= 0)
5029 low_bound = array_ref_low_bound (ref);
5031 if (TREE_CODE (low_sub) == SSA_NAME)
5033 vr = get_value_range (low_sub);
5034 if (vr->type == VR_RANGE || vr->type == VR_ANTI_RANGE)
5036 low_sub = vr->type == VR_RANGE ? vr->max : vr->min;
5037 up_sub = vr->type == VR_RANGE ? vr->min : vr->max;
5041 if (vr && vr->type == VR_ANTI_RANGE)
5043 if (TREE_CODE (up_sub) == INTEGER_CST
5044 && tree_int_cst_lt (up_bound, up_sub)
5045 && TREE_CODE (low_sub) == INTEGER_CST
5046 && tree_int_cst_lt (low_sub, low_bound))
5048 warning (OPT_Warray_bounds,
5049 "%Harray subscript is outside array bounds", location);
5050 TREE_NO_WARNING (ref) = 1;
5053 else if (TREE_CODE (up_sub) == INTEGER_CST
5054 && tree_int_cst_lt (up_bound, up_sub)
5055 && !tree_int_cst_equal (up_bound, up_sub)
5056 && (!ignore_off_by_one
5057 || !tree_int_cst_equal (int_const_binop (PLUS_EXPR,
5063 warning (OPT_Warray_bounds, "%Harray subscript is above array bounds",
5065 TREE_NO_WARNING (ref) = 1;
5067 else if (TREE_CODE (low_sub) == INTEGER_CST
5068 && tree_int_cst_lt (low_sub, low_bound))
5070 warning (OPT_Warray_bounds, "%Harray subscript is below array bounds",
5072 TREE_NO_WARNING (ref) = 1;
5076 /* Searches if the expr T, located at LOCATION computes
5077 address of an ARRAY_REF, and call check_array_ref on it. */
5080 search_for_addr_array (tree t, const location_t *location)
5082 while (TREE_CODE (t) == SSA_NAME)
5084 gimple g = SSA_NAME_DEF_STMT (t);
5086 if (gimple_code (g) != GIMPLE_ASSIGN)
5089 if (get_gimple_rhs_class (gimple_assign_rhs_code (g))
5090 != GIMPLE_SINGLE_RHS)
5093 t = gimple_assign_rhs1 (g);
5097 /* We are only interested in addresses of ARRAY_REF's. */
5098 if (TREE_CODE (t) != ADDR_EXPR)
5101 /* Check each ARRAY_REFs in the reference chain. */
5104 if (TREE_CODE (t) == ARRAY_REF)
5105 check_array_ref (t, location, true /*ignore_off_by_one*/);
5107 t = TREE_OPERAND (t, 0);
5109 while (handled_component_p (t));
5112 /* walk_tree() callback that checks if *TP is
5113 an ARRAY_REF inside an ADDR_EXPR (in which an array
5114 subscript one outside the valid range is allowed). Call
5115 check_array_ref for each ARRAY_REF found. The location is
5119 check_array_bounds (tree *tp, int *walk_subtree, void *data)
5122 struct walk_stmt_info *wi = (struct walk_stmt_info *) data;
5123 const location_t *location = (const location_t *) wi->info;
5125 *walk_subtree = TRUE;
5127 if (TREE_CODE (t) == ARRAY_REF)
5128 check_array_ref (t, location, false /*ignore_off_by_one*/);
5130 if (TREE_CODE (t) == INDIRECT_REF
5131 || (TREE_CODE (t) == RETURN_EXPR && TREE_OPERAND (t, 0)))
5132 search_for_addr_array (TREE_OPERAND (t, 0), location);
5134 if (TREE_CODE (t) == ADDR_EXPR)
5135 *walk_subtree = FALSE;
5140 /* Walk over all statements of all reachable BBs and call check_array_bounds
5144 check_all_array_refs (void)
5147 gimple_stmt_iterator si;
5151 /* Skip bb's that are clearly unreachable. */
5152 if (single_pred_p (bb))
5154 basic_block pred_bb = EDGE_PRED (bb, 0)->src;
5157 if (!gsi_end_p (gsi_last_bb (pred_bb)))
5158 ls = gsi_stmt (gsi_last_bb (pred_bb));
5160 if (ls && gimple_code (ls) == GIMPLE_COND
5161 && ((gimple_cond_false_p (ls)
5162 && (EDGE_PRED (bb, 0)->flags & EDGE_TRUE_VALUE))
5163 || (gimple_cond_true_p (ls)
5164 && (EDGE_PRED (bb, 0)->flags & EDGE_FALSE_VALUE))))
5167 for (si = gsi_start_bb (bb); !gsi_end_p (si); gsi_next (&si))
5169 gimple stmt = gsi_stmt (si);
5170 const location_t *location = gimple_location_ptr (stmt);
5171 struct walk_stmt_info wi;
5172 if (!gimple_has_location (stmt))
5175 if (is_gimple_call (stmt))
5178 size_t n = gimple_call_num_args (stmt);
5179 for (i = 0; i < n; i++)
5181 tree arg = gimple_call_arg (stmt, i);
5182 search_for_addr_array (arg, location);
5187 memset (&wi, 0, sizeof (wi));
5188 wi.info = CONST_CAST (void *, (const void *) location);
5190 walk_gimple_op (gsi_stmt (si),
5198 /* Convert range assertion expressions into the implied copies and
5199 copy propagate away the copies. Doing the trivial copy propagation
5200 here avoids the need to run the full copy propagation pass after
5203 FIXME, this will eventually lead to copy propagation removing the
5204 names that had useful range information attached to them. For
5205 instance, if we had the assertion N_i = ASSERT_EXPR <N_j, N_j > 3>,
5206 then N_i will have the range [3, +INF].
5208 However, by converting the assertion into the implied copy
5209 operation N_i = N_j, we will then copy-propagate N_j into the uses
5210 of N_i and lose the range information. We may want to hold on to
5211 ASSERT_EXPRs a little while longer as the ranges could be used in
5212 things like jump threading.
5214 The problem with keeping ASSERT_EXPRs around is that passes after
5215 VRP need to handle them appropriately.
5217 Another approach would be to make the range information a first
5218 class property of the SSA_NAME so that it can be queried from
5219 any pass. This is made somewhat more complex by the need for
5220 multiple ranges to be associated with one SSA_NAME. */
5223 remove_range_assertions (void)
5226 gimple_stmt_iterator si;
5228 /* Note that the BSI iterator bump happens at the bottom of the
5229 loop and no bump is necessary if we're removing the statement
5230 referenced by the current BSI. */
5232 for (si = gsi_start_bb (bb); !gsi_end_p (si);)
5234 gimple stmt = gsi_stmt (si);
5237 if (is_gimple_assign (stmt)
5238 && gimple_assign_rhs_code (stmt) == ASSERT_EXPR)
5240 tree rhs = gimple_assign_rhs1 (stmt);
5242 tree cond = fold (ASSERT_EXPR_COND (rhs));
5243 use_operand_p use_p;
5244 imm_use_iterator iter;
5246 gcc_assert (cond != boolean_false_node);
5248 /* Propagate the RHS into every use of the LHS. */
5249 var = ASSERT_EXPR_VAR (rhs);
5250 FOR_EACH_IMM_USE_STMT (use_stmt, iter,
5251 gimple_assign_lhs (stmt))
5252 FOR_EACH_IMM_USE_ON_STMT (use_p, iter)
5254 SET_USE (use_p, var);
5255 gcc_assert (TREE_CODE (var) == SSA_NAME);
5258 /* And finally, remove the copy, it is not needed. */
5259 gsi_remove (&si, true);
5260 release_defs (stmt);
5268 /* Return true if STMT is interesting for VRP. */
5271 stmt_interesting_for_vrp (gimple stmt)
5273 if (gimple_code (stmt) == GIMPLE_PHI
5274 && is_gimple_reg (gimple_phi_result (stmt))
5275 && (INTEGRAL_TYPE_P (TREE_TYPE (gimple_phi_result (stmt)))
5276 || POINTER_TYPE_P (TREE_TYPE (gimple_phi_result (stmt)))))
5278 else if (is_gimple_assign (stmt) || is_gimple_call (stmt))
5280 tree lhs = gimple_get_lhs (stmt);
5282 /* In general, assignments with virtual operands are not useful
5283 for deriving ranges, with the obvious exception of calls to
5284 builtin functions. */
5285 if (lhs && TREE_CODE (lhs) == SSA_NAME
5286 && (INTEGRAL_TYPE_P (TREE_TYPE (lhs))
5287 || POINTER_TYPE_P (TREE_TYPE (lhs)))
5288 && ((is_gimple_call (stmt)
5289 && gimple_call_fndecl (stmt) != NULL_TREE
5290 && DECL_IS_BUILTIN (gimple_call_fndecl (stmt)))
5291 || ZERO_SSA_OPERANDS (stmt, SSA_OP_ALL_VIRTUALS)))
5294 else if (gimple_code (stmt) == GIMPLE_COND
5295 || gimple_code (stmt) == GIMPLE_SWITCH)
5302 /* Initialize local data structures for VRP. */
5305 vrp_initialize (void)
5309 vr_value = XCNEWVEC (value_range_t *, num_ssa_names);
5310 vr_phi_edge_counts = XCNEWVEC (int, num_ssa_names);
5314 gimple_stmt_iterator si;
5316 for (si = gsi_start_phis (bb); !gsi_end_p (si); gsi_next (&si))
5318 gimple phi = gsi_stmt (si);
5319 if (!stmt_interesting_for_vrp (phi))
5321 tree lhs = PHI_RESULT (phi);
5322 set_value_range_to_varying (get_value_range (lhs));
5323 prop_set_simulate_again (phi, false);
5326 prop_set_simulate_again (phi, true);
5329 for (si = gsi_start_bb (bb); !gsi_end_p (si); gsi_next (&si))
5331 gimple stmt = gsi_stmt (si);
5333 if (!stmt_interesting_for_vrp (stmt))
5337 FOR_EACH_SSA_TREE_OPERAND (def, stmt, i, SSA_OP_DEF)
5338 set_value_range_to_varying (get_value_range (def));
5339 prop_set_simulate_again (stmt, false);
5343 prop_set_simulate_again (stmt, true);
5350 /* Visit assignment STMT. If it produces an interesting range, record
5351 the SSA name in *OUTPUT_P. */
5353 static enum ssa_prop_result
5354 vrp_visit_assignment_or_call (gimple stmt, tree *output_p)
5358 enum gimple_code code = gimple_code (stmt);
5359 lhs = gimple_get_lhs (stmt);
5361 /* We only keep track of ranges in integral and pointer types. */
5362 if (TREE_CODE (lhs) == SSA_NAME
5363 && ((INTEGRAL_TYPE_P (TREE_TYPE (lhs))
5364 /* It is valid to have NULL MIN/MAX values on a type. See
5365 build_range_type. */
5366 && TYPE_MIN_VALUE (TREE_TYPE (lhs))
5367 && TYPE_MAX_VALUE (TREE_TYPE (lhs)))
5368 || POINTER_TYPE_P (TREE_TYPE (lhs))))
5371 value_range_t new_vr = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
5373 if (code == GIMPLE_CALL)
5374 extract_range_basic (&new_vr, stmt);
5376 extract_range_from_assignment (&new_vr, stmt);
5378 /* If STMT is inside a loop, we may be able to know something
5379 else about the range of LHS by examining scalar evolution
5381 if (current_loops && (l = loop_containing_stmt (stmt)))
5382 adjust_range_with_scev (&new_vr, l, stmt, lhs);
5384 if (update_value_range (lhs, &new_vr))
5388 if (dump_file && (dump_flags & TDF_DETAILS))
5390 fprintf (dump_file, "Found new range for ");
5391 print_generic_expr (dump_file, lhs, 0);
5392 fprintf (dump_file, ": ");
5393 dump_value_range (dump_file, &new_vr);
5394 fprintf (dump_file, "\n\n");
5397 if (new_vr.type == VR_VARYING)
5398 return SSA_PROP_VARYING;
5400 return SSA_PROP_INTERESTING;
5403 return SSA_PROP_NOT_INTERESTING;
5406 /* Every other statement produces no useful ranges. */
5407 FOR_EACH_SSA_TREE_OPERAND (def, stmt, iter, SSA_OP_DEF)
5408 set_value_range_to_varying (get_value_range (def));
5410 return SSA_PROP_VARYING;
5413 /* Helper that gets the value range of the SSA_NAME with version I
5414 or a symbolic range containing the SSA_NAME only if the value range
5415 is varying or undefined. */
5417 static inline value_range_t
5418 get_vr_for_comparison (int i)
5420 value_range_t vr = *(vr_value[i]);
5422 /* If name N_i does not have a valid range, use N_i as its own
5423 range. This allows us to compare against names that may
5424 have N_i in their ranges. */
5425 if (vr.type == VR_VARYING || vr.type == VR_UNDEFINED)
5428 vr.min = ssa_name (i);
5429 vr.max = ssa_name (i);
5435 /* Compare all the value ranges for names equivalent to VAR with VAL
5436 using comparison code COMP. Return the same value returned by
5437 compare_range_with_value, including the setting of
5438 *STRICT_OVERFLOW_P. */
5441 compare_name_with_value (enum tree_code comp, tree var, tree val,
5442 bool *strict_overflow_p)
5448 int used_strict_overflow;
5450 value_range_t equiv_vr;
5452 /* Get the set of equivalences for VAR. */
5453 e = get_value_range (var)->equiv;
5455 /* Start at -1. Set it to 0 if we do a comparison without relying
5456 on overflow, or 1 if all comparisons rely on overflow. */
5457 used_strict_overflow = -1;
5459 /* Compare vars' value range with val. */
5460 equiv_vr = get_vr_for_comparison (SSA_NAME_VERSION (var));
5462 retval = compare_range_with_value (comp, &equiv_vr, val, &sop);
5464 used_strict_overflow = sop ? 1 : 0;
5466 /* If the equiv set is empty we have done all work we need to do. */
5470 && used_strict_overflow > 0)
5471 *strict_overflow_p = true;
5475 EXECUTE_IF_SET_IN_BITMAP (e, 0, i, bi)
5477 equiv_vr = get_vr_for_comparison (i);
5479 t = compare_range_with_value (comp, &equiv_vr, val, &sop);
5482 /* If we get different answers from different members
5483 of the equivalence set this check must be in a dead
5484 code region. Folding it to a trap representation
5485 would be correct here. For now just return don't-know. */
5495 used_strict_overflow = 0;
5496 else if (used_strict_overflow < 0)
5497 used_strict_overflow = 1;
5502 && used_strict_overflow > 0)
5503 *strict_overflow_p = true;
5509 /* Given a comparison code COMP and names N1 and N2, compare all the
5510 ranges equivalent to N1 against all the ranges equivalent to N2
5511 to determine the value of N1 COMP N2. Return the same value
5512 returned by compare_ranges. Set *STRICT_OVERFLOW_P to indicate
5513 whether we relied on an overflow infinity in the comparison. */
5517 compare_names (enum tree_code comp, tree n1, tree n2,
5518 bool *strict_overflow_p)
5522 bitmap_iterator bi1, bi2;
5524 int used_strict_overflow;
5525 static bitmap_obstack *s_obstack = NULL;
5526 static bitmap s_e1 = NULL, s_e2 = NULL;
5528 /* Compare the ranges of every name equivalent to N1 against the
5529 ranges of every name equivalent to N2. */
5530 e1 = get_value_range (n1)->equiv;
5531 e2 = get_value_range (n2)->equiv;
5533 /* Use the fake bitmaps if e1 or e2 are not available. */
5534 if (s_obstack == NULL)
5536 s_obstack = XNEW (bitmap_obstack);
5537 bitmap_obstack_initialize (s_obstack);
5538 s_e1 = BITMAP_ALLOC (s_obstack);
5539 s_e2 = BITMAP_ALLOC (s_obstack);
5546 /* Add N1 and N2 to their own set of equivalences to avoid
5547 duplicating the body of the loop just to check N1 and N2
5549 bitmap_set_bit (e1, SSA_NAME_VERSION (n1));
5550 bitmap_set_bit (e2, SSA_NAME_VERSION (n2));
5552 /* If the equivalence sets have a common intersection, then the two
5553 names can be compared without checking their ranges. */
5554 if (bitmap_intersect_p (e1, e2))
5556 bitmap_clear_bit (e1, SSA_NAME_VERSION (n1));
5557 bitmap_clear_bit (e2, SSA_NAME_VERSION (n2));
5559 return (comp == EQ_EXPR || comp == GE_EXPR || comp == LE_EXPR)
5561 : boolean_false_node;
5564 /* Start at -1. Set it to 0 if we do a comparison without relying
5565 on overflow, or 1 if all comparisons rely on overflow. */
5566 used_strict_overflow = -1;
5568 /* Otherwise, compare all the equivalent ranges. First, add N1 and
5569 N2 to their own set of equivalences to avoid duplicating the body
5570 of the loop just to check N1 and N2 ranges. */
5571 EXECUTE_IF_SET_IN_BITMAP (e1, 0, i1, bi1)
5573 value_range_t vr1 = get_vr_for_comparison (i1);
5575 t = retval = NULL_TREE;
5576 EXECUTE_IF_SET_IN_BITMAP (e2, 0, i2, bi2)
5580 value_range_t vr2 = get_vr_for_comparison (i2);
5582 t = compare_ranges (comp, &vr1, &vr2, &sop);
5585 /* If we get different answers from different members
5586 of the equivalence set this check must be in a dead
5587 code region. Folding it to a trap representation
5588 would be correct here. For now just return don't-know. */
5592 bitmap_clear_bit (e1, SSA_NAME_VERSION (n1));
5593 bitmap_clear_bit (e2, SSA_NAME_VERSION (n2));
5599 used_strict_overflow = 0;
5600 else if (used_strict_overflow < 0)
5601 used_strict_overflow = 1;
5607 bitmap_clear_bit (e1, SSA_NAME_VERSION (n1));
5608 bitmap_clear_bit (e2, SSA_NAME_VERSION (n2));
5609 if (used_strict_overflow > 0)
5610 *strict_overflow_p = true;
5615 /* None of the equivalent ranges are useful in computing this
5617 bitmap_clear_bit (e1, SSA_NAME_VERSION (n1));
5618 bitmap_clear_bit (e2, SSA_NAME_VERSION (n2));
5622 /* Helper function for vrp_evaluate_conditional_warnv. */
5625 vrp_evaluate_conditional_warnv_with_ops_using_ranges (enum tree_code code,
5627 bool * strict_overflow_p)
5629 value_range_t *vr0, *vr1;
5631 vr0 = (TREE_CODE (op0) == SSA_NAME) ? get_value_range (op0) : NULL;
5632 vr1 = (TREE_CODE (op1) == SSA_NAME) ? get_value_range (op1) : NULL;
5635 return compare_ranges (code, vr0, vr1, strict_overflow_p);
5636 else if (vr0 && vr1 == NULL)
5637 return compare_range_with_value (code, vr0, op1, strict_overflow_p);
5638 else if (vr0 == NULL && vr1)
5639 return (compare_range_with_value
5640 (swap_tree_comparison (code), vr1, op0, strict_overflow_p));
5644 /* Helper function for vrp_evaluate_conditional_warnv. */
5647 vrp_evaluate_conditional_warnv_with_ops (enum tree_code code, tree op0,
5648 tree op1, bool use_equiv_p,
5649 bool *strict_overflow_p, bool *only_ranges)
5653 *only_ranges = true;
5655 /* We only deal with integral and pointer types. */
5656 if (!INTEGRAL_TYPE_P (TREE_TYPE (op0))
5657 && !POINTER_TYPE_P (TREE_TYPE (op0)))
5663 && (ret = vrp_evaluate_conditional_warnv_with_ops_using_ranges
5664 (code, op0, op1, strict_overflow_p)))
5666 *only_ranges = false;
5667 if (TREE_CODE (op0) == SSA_NAME && TREE_CODE (op1) == SSA_NAME)
5668 return compare_names (code, op0, op1, strict_overflow_p);
5669 else if (TREE_CODE (op0) == SSA_NAME)
5670 return compare_name_with_value (code, op0, op1, strict_overflow_p);
5671 else if (TREE_CODE (op1) == SSA_NAME)
5672 return (compare_name_with_value
5673 (swap_tree_comparison (code), op1, op0, strict_overflow_p));
5676 return vrp_evaluate_conditional_warnv_with_ops_using_ranges (code, op0, op1,
5681 /* Given (CODE OP0 OP1) within STMT, try to simplify it based on value range
5682 information. Return NULL if the conditional can not be evaluated.
5683 The ranges of all the names equivalent with the operands in COND
5684 will be used when trying to compute the value. If the result is
5685 based on undefined signed overflow, issue a warning if
5689 vrp_evaluate_conditional (enum tree_code code, tree op0, tree op1, gimple stmt)
5695 /* Some passes and foldings leak constants with overflow flag set
5696 into the IL. Avoid doing wrong things with these and bail out. */
5697 if ((TREE_CODE (op0) == INTEGER_CST
5698 && TREE_OVERFLOW (op0))
5699 || (TREE_CODE (op1) == INTEGER_CST
5700 && TREE_OVERFLOW (op1)))
5704 ret = vrp_evaluate_conditional_warnv_with_ops (code, op0, op1, true, &sop,
5709 enum warn_strict_overflow_code wc;
5710 const char* warnmsg;
5712 if (is_gimple_min_invariant (ret))
5714 wc = WARN_STRICT_OVERFLOW_CONDITIONAL;
5715 warnmsg = G_("assuming signed overflow does not occur when "
5716 "simplifying conditional to constant");
5720 wc = WARN_STRICT_OVERFLOW_COMPARISON;
5721 warnmsg = G_("assuming signed overflow does not occur when "
5722 "simplifying conditional");
5725 if (issue_strict_overflow_warning (wc))
5727 location_t location;
5729 if (!gimple_has_location (stmt))
5730 location = input_location;
5732 location = gimple_location (stmt);
5733 warning (OPT_Wstrict_overflow, "%H%s", &location, warnmsg);
5737 if (warn_type_limits
5738 && ret && only_ranges
5739 && TREE_CODE_CLASS (code) == tcc_comparison
5740 && TREE_CODE (op0) == SSA_NAME)
5742 /* If the comparison is being folded and the operand on the LHS
5743 is being compared against a constant value that is outside of
5744 the natural range of OP0's type, then the predicate will
5745 always fold regardless of the value of OP0. If -Wtype-limits
5746 was specified, emit a warning. */
5747 const char *warnmsg = NULL;
5748 tree type = TREE_TYPE (op0);
5749 value_range_t *vr0 = get_value_range (op0);
5751 if (vr0->type != VR_VARYING
5752 && INTEGRAL_TYPE_P (type)
5753 && vrp_val_is_min (vr0->min)
5754 && vrp_val_is_max (vr0->max)
5755 && is_gimple_min_invariant (op1))
5757 if (integer_zerop (ret))
5758 warnmsg = G_("comparison always false due to limited range of "
5761 warnmsg = G_("comparison always true due to limited range of "
5767 location_t location;
5769 if (!gimple_has_location (stmt))
5770 location = input_location;
5772 location = gimple_location (stmt);
5774 warning (OPT_Wtype_limits, "%H%s", &location, warnmsg);
5782 /* Visit conditional statement STMT. If we can determine which edge
5783 will be taken out of STMT's basic block, record it in
5784 *TAKEN_EDGE_P and return SSA_PROP_INTERESTING. Otherwise, return
5785 SSA_PROP_VARYING. */
5787 static enum ssa_prop_result
5788 vrp_visit_cond_stmt (gimple stmt, edge *taken_edge_p)
5793 *taken_edge_p = NULL;
5795 if (dump_file && (dump_flags & TDF_DETAILS))
5800 fprintf (dump_file, "\nVisiting conditional with predicate: ");
5801 print_gimple_stmt (dump_file, stmt, 0, 0);
5802 fprintf (dump_file, "\nWith known ranges\n");
5804 FOR_EACH_SSA_TREE_OPERAND (use, stmt, i, SSA_OP_USE)
5806 fprintf (dump_file, "\t");
5807 print_generic_expr (dump_file, use, 0);
5808 fprintf (dump_file, ": ");
5809 dump_value_range (dump_file, vr_value[SSA_NAME_VERSION (use)]);
5812 fprintf (dump_file, "\n");
5815 /* Compute the value of the predicate COND by checking the known
5816 ranges of each of its operands.
5818 Note that we cannot evaluate all the equivalent ranges here
5819 because those ranges may not yet be final and with the current
5820 propagation strategy, we cannot determine when the value ranges
5821 of the names in the equivalence set have changed.
5823 For instance, given the following code fragment
5827 i_14 = ASSERT_EXPR <i_5, i_5 != 0>
5831 Assume that on the first visit to i_14, i_5 has the temporary
5832 range [8, 8] because the second argument to the PHI function is
5833 not yet executable. We derive the range ~[0, 0] for i_14 and the
5834 equivalence set { i_5 }. So, when we visit 'if (i_14 == 1)' for
5835 the first time, since i_14 is equivalent to the range [8, 8], we
5836 determine that the predicate is always false.
5838 On the next round of propagation, i_13 is determined to be
5839 VARYING, which causes i_5 to drop down to VARYING. So, another
5840 visit to i_14 is scheduled. In this second visit, we compute the
5841 exact same range and equivalence set for i_14, namely ~[0, 0] and
5842 { i_5 }. But we did not have the previous range for i_5
5843 registered, so vrp_visit_assignment thinks that the range for
5844 i_14 has not changed. Therefore, the predicate 'if (i_14 == 1)'
5845 is not visited again, which stops propagation from visiting
5846 statements in the THEN clause of that if().
5848 To properly fix this we would need to keep the previous range
5849 value for the names in the equivalence set. This way we would've
5850 discovered that from one visit to the other i_5 changed from
5851 range [8, 8] to VR_VARYING.
5853 However, fixing this apparent limitation may not be worth the
5854 additional checking. Testing on several code bases (GCC, DLV,
5855 MICO, TRAMP3D and SPEC2000) showed that doing this results in
5856 4 more predicates folded in SPEC. */
5859 val = vrp_evaluate_conditional_warnv_with_ops (gimple_cond_code (stmt),
5860 gimple_cond_lhs (stmt),
5861 gimple_cond_rhs (stmt),
5866 *taken_edge_p = find_taken_edge (gimple_bb (stmt), val);
5869 if (dump_file && (dump_flags & TDF_DETAILS))
5871 "\nIgnoring predicate evaluation because "
5872 "it assumes that signed overflow is undefined");
5877 if (dump_file && (dump_flags & TDF_DETAILS))
5879 fprintf (dump_file, "\nPredicate evaluates to: ");
5880 if (val == NULL_TREE)
5881 fprintf (dump_file, "DON'T KNOW\n");
5883 print_generic_stmt (dump_file, val, 0);
5886 return (*taken_edge_p) ? SSA_PROP_INTERESTING : SSA_PROP_VARYING;
5889 /* Searches the case label vector VEC for the index *IDX of the CASE_LABEL
5890 that includes the value VAL. The search is restricted to the range
5891 [START_IDX, n - 1] where n is the size of VEC.
5893 If there is a CASE_LABEL for VAL, its index is placed in IDX and true is
5896 If there is no CASE_LABEL for VAL and the is one that is larger than VAL,
5897 it is placed in IDX and false is returned.
5899 If VAL is larger than any CASE_LABEL, n is placed on IDX and false is
5903 find_case_label_index (gimple stmt, size_t start_idx, tree val, size_t *idx)
5905 size_t n = gimple_switch_num_labels (stmt);
5908 /* Find case label for minimum of the value range or the next one.
5909 At each iteration we are searching in [low, high - 1]. */
5911 for (low = start_idx, high = n; high != low; )
5915 /* Note that i != high, so we never ask for n. */
5916 size_t i = (high + low) / 2;
5917 t = gimple_switch_label (stmt, i);
5919 /* Cache the result of comparing CASE_LOW and val. */
5920 cmp = tree_int_cst_compare (CASE_LOW (t), val);
5924 /* Ranges cannot be empty. */
5933 if (CASE_HIGH (t) != NULL
5934 && tree_int_cst_compare (CASE_HIGH (t), val) >= 0)
5946 /* Searches the case label vector VEC for the range of CASE_LABELs that is used
5947 for values between MIN and MAX. The first index is placed in MIN_IDX. The
5948 last index is placed in MAX_IDX. If the range of CASE_LABELs is empty
5949 then MAX_IDX < MIN_IDX.
5950 Returns true if the default label is not needed. */
5953 find_case_label_range (gimple stmt, tree min, tree max, size_t *min_idx,
5957 bool min_take_default = !find_case_label_index (stmt, 1, min, &i);
5958 bool max_take_default = !find_case_label_index (stmt, i, max, &j);
5962 && max_take_default)
5964 /* Only the default case label reached.
5965 Return an empty range. */
5972 bool take_default = min_take_default || max_take_default;
5976 if (max_take_default)
5979 /* If the case label range is continuous, we do not need
5980 the default case label. Verify that. */
5981 high = CASE_LOW (gimple_switch_label (stmt, i));
5982 if (CASE_HIGH (gimple_switch_label (stmt, i)))
5983 high = CASE_HIGH (gimple_switch_label (stmt, i));
5984 for (k = i + 1; k <= j; ++k)
5986 low = CASE_LOW (gimple_switch_label (stmt, k));
5987 if (!integer_onep (int_const_binop (MINUS_EXPR, low, high, 0)))
5989 take_default = true;
5993 if (CASE_HIGH (gimple_switch_label (stmt, k)))
5994 high = CASE_HIGH (gimple_switch_label (stmt, k));
5999 return !take_default;
6003 /* Visit switch statement STMT. If we can determine which edge
6004 will be taken out of STMT's basic block, record it in
6005 *TAKEN_EDGE_P and return SSA_PROP_INTERESTING. Otherwise, return
6006 SSA_PROP_VARYING. */
6008 static enum ssa_prop_result
6009 vrp_visit_switch_stmt (gimple stmt, edge *taken_edge_p)
6013 size_t i = 0, j = 0, n;
6016 *taken_edge_p = NULL;
6017 op = gimple_switch_index (stmt);
6018 if (TREE_CODE (op) != SSA_NAME)
6019 return SSA_PROP_VARYING;
6021 vr = get_value_range (op);
6022 if (dump_file && (dump_flags & TDF_DETAILS))
6024 fprintf (dump_file, "\nVisiting switch expression with operand ");
6025 print_generic_expr (dump_file, op, 0);
6026 fprintf (dump_file, " with known range ");
6027 dump_value_range (dump_file, vr);
6028 fprintf (dump_file, "\n");
6031 if (vr->type != VR_RANGE
6032 || symbolic_range_p (vr))
6033 return SSA_PROP_VARYING;
6035 /* Find the single edge that is taken from the switch expression. */
6036 n = gimple_switch_num_labels (stmt);
6038 take_default = !find_case_label_range (stmt, vr->min, vr->max, &i, &j);
6040 /* Check if the range spans no CASE_LABEL. If so, we only reach the default
6044 gcc_assert (take_default);
6045 val = gimple_switch_default_label (stmt);
6049 /* Check if labels with index i to j and maybe the default label
6050 are all reaching the same label. */
6052 val = gimple_switch_label (stmt, i);
6054 && CASE_LABEL (gimple_switch_default_label (stmt))
6055 != CASE_LABEL (val))
6057 if (dump_file && (dump_flags & TDF_DETAILS))
6058 fprintf (dump_file, " not a single destination for this "
6060 return SSA_PROP_VARYING;
6062 for (++i; i <= j; ++i)
6064 if (CASE_LABEL (gimple_switch_label (stmt, i)) != CASE_LABEL (val))
6066 if (dump_file && (dump_flags & TDF_DETAILS))
6067 fprintf (dump_file, " not a single destination for this "
6069 return SSA_PROP_VARYING;
6074 *taken_edge_p = find_edge (gimple_bb (stmt),
6075 label_to_block (CASE_LABEL (val)));
6077 if (dump_file && (dump_flags & TDF_DETAILS))
6079 fprintf (dump_file, " will take edge to ");
6080 print_generic_stmt (dump_file, CASE_LABEL (val), 0);
6083 return SSA_PROP_INTERESTING;
6087 /* Evaluate statement STMT. If the statement produces a useful range,
6088 return SSA_PROP_INTERESTING and record the SSA name with the
6089 interesting range into *OUTPUT_P.
6091 If STMT is a conditional branch and we can determine its truth
6092 value, the taken edge is recorded in *TAKEN_EDGE_P.
6094 If STMT produces a varying value, return SSA_PROP_VARYING. */
6096 static enum ssa_prop_result
6097 vrp_visit_stmt (gimple stmt, edge *taken_edge_p, tree *output_p)
6102 if (dump_file && (dump_flags & TDF_DETAILS))
6104 fprintf (dump_file, "\nVisiting statement:\n");
6105 print_gimple_stmt (dump_file, stmt, 0, dump_flags);
6106 fprintf (dump_file, "\n");
6109 if (is_gimple_assign (stmt) || is_gimple_call (stmt))
6111 /* In general, assignments with virtual operands are not useful
6112 for deriving ranges, with the obvious exception of calls to
6113 builtin functions. */
6115 if ((is_gimple_call (stmt)
6116 && gimple_call_fndecl (stmt) != NULL_TREE
6117 && DECL_IS_BUILTIN (gimple_call_fndecl (stmt)))
6118 || ZERO_SSA_OPERANDS (stmt, SSA_OP_ALL_VIRTUALS))
6119 return vrp_visit_assignment_or_call (stmt, output_p);
6121 else if (gimple_code (stmt) == GIMPLE_COND)
6122 return vrp_visit_cond_stmt (stmt, taken_edge_p);
6123 else if (gimple_code (stmt) == GIMPLE_SWITCH)
6124 return vrp_visit_switch_stmt (stmt, taken_edge_p);
6126 /* All other statements produce nothing of interest for VRP, so mark
6127 their outputs varying and prevent further simulation. */
6128 FOR_EACH_SSA_TREE_OPERAND (def, stmt, iter, SSA_OP_DEF)
6129 set_value_range_to_varying (get_value_range (def));
6131 return SSA_PROP_VARYING;
6135 /* Meet operation for value ranges. Given two value ranges VR0 and
6136 VR1, store in VR0 a range that contains both VR0 and VR1. This
6137 may not be the smallest possible such range. */
6140 vrp_meet (value_range_t *vr0, value_range_t *vr1)
6142 if (vr0->type == VR_UNDEFINED)
6144 copy_value_range (vr0, vr1);
6148 if (vr1->type == VR_UNDEFINED)
6150 /* Nothing to do. VR0 already has the resulting range. */
6154 if (vr0->type == VR_VARYING)
6156 /* Nothing to do. VR0 already has the resulting range. */
6160 if (vr1->type == VR_VARYING)
6162 set_value_range_to_varying (vr0);
6166 if (vr0->type == VR_RANGE && vr1->type == VR_RANGE)
6171 /* Compute the convex hull of the ranges. The lower limit of
6172 the new range is the minimum of the two ranges. If they
6173 cannot be compared, then give up. */
6174 cmp = compare_values (vr0->min, vr1->min);
6175 if (cmp == 0 || cmp == 1)
6182 /* Similarly, the upper limit of the new range is the maximum
6183 of the two ranges. If they cannot be compared, then
6185 cmp = compare_values (vr0->max, vr1->max);
6186 if (cmp == 0 || cmp == -1)
6193 /* Check for useless ranges. */
6194 if (INTEGRAL_TYPE_P (TREE_TYPE (min))
6195 && ((vrp_val_is_min (min) || is_overflow_infinity (min))
6196 && (vrp_val_is_max (max) || is_overflow_infinity (max))))
6199 /* The resulting set of equivalences is the intersection of
6201 if (vr0->equiv && vr1->equiv && vr0->equiv != vr1->equiv)
6202 bitmap_and_into (vr0->equiv, vr1->equiv);
6203 else if (vr0->equiv && !vr1->equiv)
6204 bitmap_clear (vr0->equiv);
6206 set_value_range (vr0, vr0->type, min, max, vr0->equiv);
6208 else if (vr0->type == VR_ANTI_RANGE && vr1->type == VR_ANTI_RANGE)
6210 /* Two anti-ranges meet only if their complements intersect.
6211 Only handle the case of identical ranges. */
6212 if (compare_values (vr0->min, vr1->min) == 0
6213 && compare_values (vr0->max, vr1->max) == 0
6214 && compare_values (vr0->min, vr0->max) == 0)
6216 /* The resulting set of equivalences is the intersection of
6218 if (vr0->equiv && vr1->equiv && vr0->equiv != vr1->equiv)
6219 bitmap_and_into (vr0->equiv, vr1->equiv);
6220 else if (vr0->equiv && !vr1->equiv)
6221 bitmap_clear (vr0->equiv);
6226 else if (vr0->type == VR_ANTI_RANGE || vr1->type == VR_ANTI_RANGE)
6228 /* For a numeric range [VAL1, VAL2] and an anti-range ~[VAL3, VAL4],
6229 only handle the case where the ranges have an empty intersection.
6230 The result of the meet operation is the anti-range. */
6231 if (!symbolic_range_p (vr0)
6232 && !symbolic_range_p (vr1)
6233 && !value_ranges_intersect_p (vr0, vr1))
6235 /* Copy most of VR1 into VR0. Don't copy VR1's equivalence
6236 set. We need to compute the intersection of the two
6237 equivalence sets. */
6238 if (vr1->type == VR_ANTI_RANGE)
6239 set_value_range (vr0, vr1->type, vr1->min, vr1->max, vr0->equiv);
6241 /* The resulting set of equivalences is the intersection of
6243 if (vr0->equiv && vr1->equiv && vr0->equiv != vr1->equiv)
6244 bitmap_and_into (vr0->equiv, vr1->equiv);
6245 else if (vr0->equiv && !vr1->equiv)
6246 bitmap_clear (vr0->equiv);
6257 /* Failed to find an efficient meet. Before giving up and setting
6258 the result to VARYING, see if we can at least derive a useful
6259 anti-range. FIXME, all this nonsense about distinguishing
6260 anti-ranges from ranges is necessary because of the odd
6261 semantics of range_includes_zero_p and friends. */
6262 if (!symbolic_range_p (vr0)
6263 && ((vr0->type == VR_RANGE && !range_includes_zero_p (vr0))
6264 || (vr0->type == VR_ANTI_RANGE && range_includes_zero_p (vr0)))
6265 && !symbolic_range_p (vr1)
6266 && ((vr1->type == VR_RANGE && !range_includes_zero_p (vr1))
6267 || (vr1->type == VR_ANTI_RANGE && range_includes_zero_p (vr1))))
6269 set_value_range_to_nonnull (vr0, TREE_TYPE (vr0->min));
6271 /* Since this meet operation did not result from the meeting of
6272 two equivalent names, VR0 cannot have any equivalences. */
6274 bitmap_clear (vr0->equiv);
6277 set_value_range_to_varying (vr0);
6281 /* Visit all arguments for PHI node PHI that flow through executable
6282 edges. If a valid value range can be derived from all the incoming
6283 value ranges, set a new range for the LHS of PHI. */
6285 static enum ssa_prop_result
6286 vrp_visit_phi_node (gimple phi)
6289 tree lhs = PHI_RESULT (phi);
6290 value_range_t *lhs_vr = get_value_range (lhs);
6291 value_range_t vr_result = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
6292 int edges, old_edges;
6294 copy_value_range (&vr_result, lhs_vr);
6296 if (dump_file && (dump_flags & TDF_DETAILS))
6298 fprintf (dump_file, "\nVisiting PHI node: ");
6299 print_gimple_stmt (dump_file, phi, 0, dump_flags);
6303 for (i = 0; i < gimple_phi_num_args (phi); i++)
6305 edge e = gimple_phi_arg_edge (phi, i);
6307 if (dump_file && (dump_flags & TDF_DETAILS))
6310 "\n Argument #%d (%d -> %d %sexecutable)\n",
6311 (int) i, e->src->index, e->dest->index,
6312 (e->flags & EDGE_EXECUTABLE) ? "" : "not ");
6315 if (e->flags & EDGE_EXECUTABLE)
6317 tree arg = PHI_ARG_DEF (phi, i);
6318 value_range_t vr_arg;
6322 if (TREE_CODE (arg) == SSA_NAME)
6324 vr_arg = *(get_value_range (arg));
6328 if (is_overflow_infinity (arg))
6330 arg = copy_node (arg);
6331 TREE_OVERFLOW (arg) = 0;
6334 vr_arg.type = VR_RANGE;
6337 vr_arg.equiv = NULL;
6340 if (dump_file && (dump_flags & TDF_DETAILS))
6342 fprintf (dump_file, "\t");
6343 print_generic_expr (dump_file, arg, dump_flags);
6344 fprintf (dump_file, "\n\tValue: ");
6345 dump_value_range (dump_file, &vr_arg);
6346 fprintf (dump_file, "\n");
6349 vrp_meet (&vr_result, &vr_arg);
6351 if (vr_result.type == VR_VARYING)
6356 if (vr_result.type == VR_VARYING)
6359 old_edges = vr_phi_edge_counts[SSA_NAME_VERSION (lhs)];
6360 vr_phi_edge_counts[SSA_NAME_VERSION (lhs)] = edges;
6362 /* To prevent infinite iterations in the algorithm, derive ranges
6363 when the new value is slightly bigger or smaller than the
6364 previous one. We don't do this if we have seen a new executable
6365 edge; this helps us avoid an overflow infinity for conditionals
6366 which are not in a loop. */
6367 if (lhs_vr->type == VR_RANGE && vr_result.type == VR_RANGE
6368 && edges <= old_edges)
6370 if (!POINTER_TYPE_P (TREE_TYPE (lhs)))
6372 int cmp_min = compare_values (lhs_vr->min, vr_result.min);
6373 int cmp_max = compare_values (lhs_vr->max, vr_result.max);
6375 /* If the new minimum is smaller or larger than the previous
6376 one, go all the way to -INF. In the first case, to avoid
6377 iterating millions of times to reach -INF, and in the
6378 other case to avoid infinite bouncing between different
6380 if (cmp_min > 0 || cmp_min < 0)
6382 /* If we will end up with a (-INF, +INF) range, set it to
6383 VARYING. Same if the previous max value was invalid for
6384 the type and we'd end up with vr_result.min > vr_result.max. */
6385 if (vrp_val_is_max (vr_result.max)
6386 || compare_values (TYPE_MIN_VALUE (TREE_TYPE (vr_result.min)),
6390 if (!needs_overflow_infinity (TREE_TYPE (vr_result.min))
6391 || !vrp_var_may_overflow (lhs, phi))
6392 vr_result.min = TYPE_MIN_VALUE (TREE_TYPE (vr_result.min));
6393 else if (supports_overflow_infinity (TREE_TYPE (vr_result.min)))
6395 negative_overflow_infinity (TREE_TYPE (vr_result.min));
6400 /* Similarly, if the new maximum is smaller or larger than
6401 the previous one, go all the way to +INF. */
6402 if (cmp_max < 0 || cmp_max > 0)
6404 /* If we will end up with a (-INF, +INF) range, set it to
6405 VARYING. Same if the previous min value was invalid for
6406 the type and we'd end up with vr_result.max < vr_result.min. */
6407 if (vrp_val_is_min (vr_result.min)
6408 || compare_values (TYPE_MAX_VALUE (TREE_TYPE (vr_result.max)),
6412 if (!needs_overflow_infinity (TREE_TYPE (vr_result.max))
6413 || !vrp_var_may_overflow (lhs, phi))
6414 vr_result.max = TYPE_MAX_VALUE (TREE_TYPE (vr_result.max));
6415 else if (supports_overflow_infinity (TREE_TYPE (vr_result.max)))
6417 positive_overflow_infinity (TREE_TYPE (vr_result.max));
6424 /* If the new range is different than the previous value, keep
6426 if (update_value_range (lhs, &vr_result))
6427 return SSA_PROP_INTERESTING;
6429 /* Nothing changed, don't add outgoing edges. */
6430 return SSA_PROP_NOT_INTERESTING;
6432 /* No match found. Set the LHS to VARYING. */
6434 set_value_range_to_varying (lhs_vr);
6435 return SSA_PROP_VARYING;
6438 /* Simplify boolean operations if the source is known
6439 to be already a boolean. */
6441 simplify_truth_ops_using_ranges (gimple_stmt_iterator *gsi, gimple stmt)
6443 enum tree_code rhs_code = gimple_assign_rhs_code (stmt);
6448 bool need_conversion;
6450 op0 = gimple_assign_rhs1 (stmt);
6451 if (TYPE_PRECISION (TREE_TYPE (op0)) != 1)
6453 if (TREE_CODE (op0) != SSA_NAME)
6455 vr = get_value_range (op0);
6457 val = compare_range_with_value (GE_EXPR, vr, integer_zero_node, &sop);
6458 if (!val || !integer_onep (val))
6461 val = compare_range_with_value (LE_EXPR, vr, integer_one_node, &sop);
6462 if (!val || !integer_onep (val))
6466 if (rhs_code == TRUTH_NOT_EXPR)
6469 op1 = build_int_cst (TREE_TYPE (op0), 1);
6473 op1 = gimple_assign_rhs2 (stmt);
6475 /* Reduce number of cases to handle. */
6476 if (is_gimple_min_invariant (op1))
6478 /* Exclude anything that should have been already folded. */
6479 if (rhs_code != EQ_EXPR
6480 && rhs_code != NE_EXPR
6481 && rhs_code != TRUTH_XOR_EXPR)
6484 if (!integer_zerop (op1)
6485 && !integer_onep (op1)
6486 && !integer_all_onesp (op1))
6489 /* Limit the number of cases we have to consider. */
6490 if (rhs_code == EQ_EXPR)
6493 op1 = fold_unary (TRUTH_NOT_EXPR, TREE_TYPE (op1), op1);
6498 /* Punt on A == B as there is no BIT_XNOR_EXPR. */
6499 if (rhs_code == EQ_EXPR)
6502 if (TYPE_PRECISION (TREE_TYPE (op1)) != 1)
6504 vr = get_value_range (op1);
6505 val = compare_range_with_value (GE_EXPR, vr, integer_zero_node, &sop);
6506 if (!val || !integer_onep (val))
6509 val = compare_range_with_value (LE_EXPR, vr, integer_one_node, &sop);
6510 if (!val || !integer_onep (val))
6516 if (sop && issue_strict_overflow_warning (WARN_STRICT_OVERFLOW_MISC))
6518 location_t location;
6520 if (!gimple_has_location (stmt))
6521 location = input_location;
6523 location = gimple_location (stmt);
6525 if (rhs_code == TRUTH_AND_EXPR || rhs_code == TRUTH_OR_EXPR)
6526 warning_at (location, OPT_Wstrict_overflow,
6527 _("assuming signed overflow does not occur when "
6528 "simplifying && or || to & or |"));
6530 warning_at (location, OPT_Wstrict_overflow,
6531 _("assuming signed overflow does not occur when "
6532 "simplifying ==, != or ! to identity or ^"));
6536 !useless_type_conversion_p (TREE_TYPE (gimple_assign_lhs (stmt)),
6539 /* Make sure to not sign-extend -1 as a boolean value. */
6541 && !TYPE_UNSIGNED (TREE_TYPE (op0))
6542 && TYPE_PRECISION (TREE_TYPE (op0)) == 1)
6547 case TRUTH_AND_EXPR:
6548 rhs_code = BIT_AND_EXPR;
6551 rhs_code = BIT_IOR_EXPR;
6553 case TRUTH_XOR_EXPR:
6555 if (integer_zerop (op1))
6557 gimple_assign_set_rhs_with_ops (gsi,
6558 need_conversion ? NOP_EXPR : SSA_NAME,
6560 update_stmt (gsi_stmt (*gsi));
6564 rhs_code = BIT_XOR_EXPR;
6570 if (need_conversion)
6573 gimple_assign_set_rhs_with_ops (gsi, rhs_code, op0, op1);
6574 update_stmt (gsi_stmt (*gsi));
6578 /* Simplify a division or modulo operator to a right shift or
6579 bitwise and if the first operand is unsigned or is greater
6580 than zero and the second operand is an exact power of two. */
6583 simplify_div_or_mod_using_ranges (gimple stmt)
6585 enum tree_code rhs_code = gimple_assign_rhs_code (stmt);
6587 tree op0 = gimple_assign_rhs1 (stmt);
6588 tree op1 = gimple_assign_rhs2 (stmt);
6589 value_range_t *vr = get_value_range (gimple_assign_rhs1 (stmt));
6591 if (TYPE_UNSIGNED (TREE_TYPE (op0)))
6593 val = integer_one_node;
6599 val = compare_range_with_value (GE_EXPR, vr, integer_zero_node, &sop);
6603 && integer_onep (val)
6604 && issue_strict_overflow_warning (WARN_STRICT_OVERFLOW_MISC))
6606 location_t location;
6608 if (!gimple_has_location (stmt))
6609 location = input_location;
6611 location = gimple_location (stmt);
6612 warning (OPT_Wstrict_overflow,
6613 ("%Hassuming signed overflow does not occur when "
6614 "simplifying / or %% to >> or &"),
6619 if (val && integer_onep (val))
6623 if (rhs_code == TRUNC_DIV_EXPR)
6625 t = build_int_cst (NULL_TREE, tree_log2 (op1));
6626 gimple_assign_set_rhs_code (stmt, RSHIFT_EXPR);
6627 gimple_assign_set_rhs1 (stmt, op0);
6628 gimple_assign_set_rhs2 (stmt, t);
6632 t = build_int_cst (TREE_TYPE (op1), 1);
6633 t = int_const_binop (MINUS_EXPR, op1, t, 0);
6634 t = fold_convert (TREE_TYPE (op0), t);
6636 gimple_assign_set_rhs_code (stmt, BIT_AND_EXPR);
6637 gimple_assign_set_rhs1 (stmt, op0);
6638 gimple_assign_set_rhs2 (stmt, t);
6648 /* If the operand to an ABS_EXPR is >= 0, then eliminate the
6649 ABS_EXPR. If the operand is <= 0, then simplify the
6650 ABS_EXPR into a NEGATE_EXPR. */
6653 simplify_abs_using_ranges (gimple stmt)
6656 tree op = gimple_assign_rhs1 (stmt);
6657 tree type = TREE_TYPE (op);
6658 value_range_t *vr = get_value_range (op);
6660 if (TYPE_UNSIGNED (type))
6662 val = integer_zero_node;
6668 val = compare_range_with_value (LE_EXPR, vr, integer_zero_node, &sop);
6672 val = compare_range_with_value (GE_EXPR, vr, integer_zero_node,
6677 if (integer_zerop (val))
6678 val = integer_one_node;
6679 else if (integer_onep (val))
6680 val = integer_zero_node;
6685 && (integer_onep (val) || integer_zerop (val)))
6687 if (sop && issue_strict_overflow_warning (WARN_STRICT_OVERFLOW_MISC))
6689 location_t location;
6691 if (!gimple_has_location (stmt))
6692 location = input_location;
6694 location = gimple_location (stmt);
6695 warning (OPT_Wstrict_overflow,
6696 ("%Hassuming signed overflow does not occur when "
6697 "simplifying abs (X) to X or -X"),
6701 gimple_assign_set_rhs1 (stmt, op);
6702 if (integer_onep (val))
6703 gimple_assign_set_rhs_code (stmt, NEGATE_EXPR);
6705 gimple_assign_set_rhs_code (stmt, SSA_NAME);
6714 /* We are comparing trees OP0 and OP1 using COND_CODE. OP0 has
6715 a known value range VR.
6717 If there is one and only one value which will satisfy the
6718 conditional, then return that value. Else return NULL. */
6721 test_for_singularity (enum tree_code cond_code, tree op0,
6722 tree op1, value_range_t *vr)
6727 /* Extract minimum/maximum values which satisfy the
6728 the conditional as it was written. */
6729 if (cond_code == LE_EXPR || cond_code == LT_EXPR)
6731 /* This should not be negative infinity; there is no overflow
6733 min = TYPE_MIN_VALUE (TREE_TYPE (op0));
6736 if (cond_code == LT_EXPR && !is_overflow_infinity (max))
6738 tree one = build_int_cst (TREE_TYPE (op0), 1);
6739 max = fold_build2 (MINUS_EXPR, TREE_TYPE (op0), max, one);
6741 TREE_NO_WARNING (max) = 1;
6744 else if (cond_code == GE_EXPR || cond_code == GT_EXPR)
6746 /* This should not be positive infinity; there is no overflow
6748 max = TYPE_MAX_VALUE (TREE_TYPE (op0));
6751 if (cond_code == GT_EXPR && !is_overflow_infinity (min))
6753 tree one = build_int_cst (TREE_TYPE (op0), 1);
6754 min = fold_build2 (PLUS_EXPR, TREE_TYPE (op0), min, one);
6756 TREE_NO_WARNING (min) = 1;
6760 /* Now refine the minimum and maximum values using any
6761 value range information we have for op0. */
6764 if (compare_values (vr->min, min) == -1)
6768 if (compare_values (vr->max, max) == 1)
6773 /* If the new min/max values have converged to a single value,
6774 then there is only one value which can satisfy the condition,
6775 return that value. */
6776 if (operand_equal_p (min, max, 0) && is_gimple_min_invariant (min))
6782 /* Simplify a conditional using a relational operator to an equality
6783 test if the range information indicates only one value can satisfy
6784 the original conditional. */
6787 simplify_cond_using_ranges (gimple stmt)
6789 tree op0 = gimple_cond_lhs (stmt);
6790 tree op1 = gimple_cond_rhs (stmt);
6791 enum tree_code cond_code = gimple_cond_code (stmt);
6793 if (cond_code != NE_EXPR
6794 && cond_code != EQ_EXPR
6795 && TREE_CODE (op0) == SSA_NAME
6796 && INTEGRAL_TYPE_P (TREE_TYPE (op0))
6797 && is_gimple_min_invariant (op1))
6799 value_range_t *vr = get_value_range (op0);
6801 /* If we have range information for OP0, then we might be
6802 able to simplify this conditional. */
6803 if (vr->type == VR_RANGE)
6805 tree new_tree = test_for_singularity (cond_code, op0, op1, vr);
6811 fprintf (dump_file, "Simplified relational ");
6812 print_gimple_stmt (dump_file, stmt, 0, 0);
6813 fprintf (dump_file, " into ");
6816 gimple_cond_set_code (stmt, EQ_EXPR);
6817 gimple_cond_set_lhs (stmt, op0);
6818 gimple_cond_set_rhs (stmt, new_tree);
6824 print_gimple_stmt (dump_file, stmt, 0, 0);
6825 fprintf (dump_file, "\n");
6831 /* Try again after inverting the condition. We only deal
6832 with integral types here, so no need to worry about
6833 issues with inverting FP comparisons. */
6834 cond_code = invert_tree_comparison (cond_code, false);
6835 new_tree = test_for_singularity (cond_code, op0, op1, vr);
6841 fprintf (dump_file, "Simplified relational ");
6842 print_gimple_stmt (dump_file, stmt, 0, 0);
6843 fprintf (dump_file, " into ");
6846 gimple_cond_set_code (stmt, NE_EXPR);
6847 gimple_cond_set_lhs (stmt, op0);
6848 gimple_cond_set_rhs (stmt, new_tree);
6854 print_gimple_stmt (dump_file, stmt, 0, 0);
6855 fprintf (dump_file, "\n");
6866 /* Simplify a switch statement using the value range of the switch
6870 simplify_switch_using_ranges (gimple stmt)
6872 tree op = gimple_switch_index (stmt);
6877 size_t i = 0, j = 0, n, n2;
6881 if (TREE_CODE (op) != SSA_NAME)
6884 vr = get_value_range (op);
6886 /* We can only handle integer ranges. */
6887 if (vr->type != VR_RANGE
6888 || symbolic_range_p (vr))
6891 /* Find case label for min/max of the value range. */
6892 n = gimple_switch_num_labels (stmt);
6893 take_default = !find_case_label_range (stmt, vr->min, vr->max, &i, &j);
6895 /* Bail out if this is just all edges taken. */
6901 /* Build a new vector of taken case labels. */
6902 vec2 = make_tree_vec (j - i + 1 + (int)take_default);
6905 /* Add the default edge, if necessary. */
6907 TREE_VEC_ELT (vec2, n2++) = gimple_switch_default_label (stmt);
6909 for (; i <= j; ++i, ++n2)
6910 TREE_VEC_ELT (vec2, n2) = gimple_switch_label (stmt, i);
6912 /* Mark needed edges. */
6913 for (i = 0; i < n2; ++i)
6915 e = find_edge (gimple_bb (stmt),
6916 label_to_block (CASE_LABEL (TREE_VEC_ELT (vec2, i))));
6917 e->aux = (void *)-1;
6920 /* Queue not needed edges for later removal. */
6921 FOR_EACH_EDGE (e, ei, gimple_bb (stmt)->succs)
6923 if (e->aux == (void *)-1)
6929 if (dump_file && (dump_flags & TDF_DETAILS))
6931 fprintf (dump_file, "removing unreachable case label\n");
6933 VEC_safe_push (edge, heap, to_remove_edges, e);
6936 /* And queue an update for the stmt. */
6939 VEC_safe_push (switch_update, heap, to_update_switch_stmts, &su);
6943 /* Simplify STMT using ranges if possible. */
6946 simplify_stmt_using_ranges (gimple_stmt_iterator *gsi)
6948 gimple stmt = gsi_stmt (*gsi);
6949 if (is_gimple_assign (stmt))
6951 enum tree_code rhs_code = gimple_assign_rhs_code (stmt);
6957 case TRUTH_NOT_EXPR:
6958 case TRUTH_AND_EXPR:
6960 case TRUTH_XOR_EXPR:
6961 /* Transform EQ_EXPR, NE_EXPR, TRUTH_NOT_EXPR into BIT_XOR_EXPR
6962 or identity if the RHS is zero or one, and the LHS are known
6963 to be boolean values. Transform all TRUTH_*_EXPR into
6964 BIT_*_EXPR if both arguments are known to be boolean values. */
6965 if (INTEGRAL_TYPE_P (TREE_TYPE (gimple_assign_rhs1 (stmt))))
6966 return simplify_truth_ops_using_ranges (gsi, stmt);
6969 /* Transform TRUNC_DIV_EXPR and TRUNC_MOD_EXPR into RSHIFT_EXPR
6970 and BIT_AND_EXPR respectively if the first operand is greater
6971 than zero and the second operand is an exact power of two. */
6972 case TRUNC_DIV_EXPR:
6973 case TRUNC_MOD_EXPR:
6974 if (INTEGRAL_TYPE_P (TREE_TYPE (gimple_assign_rhs1 (stmt)))
6975 && integer_pow2p (gimple_assign_rhs2 (stmt)))
6976 return simplify_div_or_mod_using_ranges (stmt);
6979 /* Transform ABS (X) into X or -X as appropriate. */
6981 if (TREE_CODE (gimple_assign_rhs1 (stmt)) == SSA_NAME
6982 && INTEGRAL_TYPE_P (TREE_TYPE (gimple_assign_rhs1 (stmt))))
6983 return simplify_abs_using_ranges (stmt);
6990 else if (gimple_code (stmt) == GIMPLE_COND)
6991 return simplify_cond_using_ranges (stmt);
6992 else if (gimple_code (stmt) == GIMPLE_SWITCH)
6993 return simplify_switch_using_ranges (stmt);
6998 /* Stack of dest,src equivalency pairs that need to be restored after
6999 each attempt to thread a block's incoming edge to an outgoing edge.
7001 A NULL entry is used to mark the end of pairs which need to be
7003 static VEC(tree,heap) *stack;
7005 /* A trivial wrapper so that we can present the generic jump threading
7006 code with a simple API for simplifying statements. STMT is the
7007 statement we want to simplify, WITHIN_STMT provides the location
7008 for any overflow warnings. */
7011 simplify_stmt_for_jump_threading (gimple stmt, gimple within_stmt)
7013 /* We only use VRP information to simplify conditionals. This is
7014 overly conservative, but it's unclear if doing more would be
7015 worth the compile time cost. */
7016 if (gimple_code (stmt) != GIMPLE_COND)
7019 return vrp_evaluate_conditional (gimple_cond_code (stmt),
7020 gimple_cond_lhs (stmt),
7021 gimple_cond_rhs (stmt), within_stmt);
7024 /* Blocks which have more than one predecessor and more than
7025 one successor present jump threading opportunities, i.e.,
7026 when the block is reached from a specific predecessor, we
7027 may be able to determine which of the outgoing edges will
7028 be traversed. When this optimization applies, we are able
7029 to avoid conditionals at runtime and we may expose secondary
7030 optimization opportunities.
7032 This routine is effectively a driver for the generic jump
7033 threading code. It basically just presents the generic code
7034 with edges that may be suitable for jump threading.
7036 Unlike DOM, we do not iterate VRP if jump threading was successful.
7037 While iterating may expose new opportunities for VRP, it is expected
7038 those opportunities would be very limited and the compile time cost
7039 to expose those opportunities would be significant.
7041 As jump threading opportunities are discovered, they are registered
7042 for later realization. */
7045 identify_jump_threads (void)
7052 /* Ugh. When substituting values earlier in this pass we can
7053 wipe the dominance information. So rebuild the dominator
7054 information as we need it within the jump threading code. */
7055 calculate_dominance_info (CDI_DOMINATORS);
7057 /* We do not allow VRP information to be used for jump threading
7058 across a back edge in the CFG. Otherwise it becomes too
7059 difficult to avoid eliminating loop exit tests. Of course
7060 EDGE_DFS_BACK is not accurate at this time so we have to
7062 mark_dfs_back_edges ();
7064 /* Do not thread across edges we are about to remove. Just marking
7065 them as EDGE_DFS_BACK will do. */
7066 for (i = 0; VEC_iterate (edge, to_remove_edges, i, e); ++i)
7067 e->flags |= EDGE_DFS_BACK;
7069 /* Allocate our unwinder stack to unwind any temporary equivalences
7070 that might be recorded. */
7071 stack = VEC_alloc (tree, heap, 20);
7073 /* To avoid lots of silly node creation, we create a single
7074 conditional and just modify it in-place when attempting to
7076 dummy = gimple_build_cond (EQ_EXPR,
7077 integer_zero_node, integer_zero_node,
7080 /* Walk through all the blocks finding those which present a
7081 potential jump threading opportunity. We could set this up
7082 as a dominator walker and record data during the walk, but
7083 I doubt it's worth the effort for the classes of jump
7084 threading opportunities we are trying to identify at this
7085 point in compilation. */
7090 /* If the generic jump threading code does not find this block
7091 interesting, then there is nothing to do. */
7092 if (! potentially_threadable_block (bb))
7095 /* We only care about blocks ending in a COND_EXPR. While there
7096 may be some value in handling SWITCH_EXPR here, I doubt it's
7097 terribly important. */
7098 last = gsi_stmt (gsi_last_bb (bb));
7099 if (gimple_code (last) != GIMPLE_COND)
7102 /* We're basically looking for any kind of conditional with
7103 integral type arguments. */
7104 if (TREE_CODE (gimple_cond_lhs (last)) == SSA_NAME
7105 && INTEGRAL_TYPE_P (TREE_TYPE (gimple_cond_lhs (last)))
7106 && (TREE_CODE (gimple_cond_rhs (last)) == SSA_NAME
7107 || is_gimple_min_invariant (gimple_cond_rhs (last)))
7108 && INTEGRAL_TYPE_P (TREE_TYPE (gimple_cond_rhs (last))))
7112 /* We've got a block with multiple predecessors and multiple
7113 successors which also ends in a suitable conditional. For
7114 each predecessor, see if we can thread it to a specific
7116 FOR_EACH_EDGE (e, ei, bb->preds)
7118 /* Do not thread across back edges or abnormal edges
7120 if (e->flags & (EDGE_DFS_BACK | EDGE_COMPLEX))
7123 thread_across_edge (dummy, e, true, &stack,
7124 simplify_stmt_for_jump_threading);
7129 /* We do not actually update the CFG or SSA graphs at this point as
7130 ASSERT_EXPRs are still in the IL and cfg cleanup code does not yet
7131 handle ASSERT_EXPRs gracefully. */
7134 /* We identified all the jump threading opportunities earlier, but could
7135 not transform the CFG at that time. This routine transforms the
7136 CFG and arranges for the dominator tree to be rebuilt if necessary.
7138 Note the SSA graph update will occur during the normal TODO
7139 processing by the pass manager. */
7141 finalize_jump_threads (void)
7143 thread_through_all_blocks (false);
7144 VEC_free (tree, heap, stack);
7148 /* Traverse all the blocks folding conditionals with known ranges. */
7154 prop_value_t *single_val_range;
7155 bool do_value_subst_p;
7159 fprintf (dump_file, "\nValue ranges after VRP:\n\n");
7160 dump_all_value_ranges (dump_file);
7161 fprintf (dump_file, "\n");
7164 /* We may have ended with ranges that have exactly one value. Those
7165 values can be substituted as any other copy/const propagated
7166 value using substitute_and_fold. */
7167 single_val_range = XCNEWVEC (prop_value_t, num_ssa_names);
7169 do_value_subst_p = false;
7170 for (i = 0; i < num_ssa_names; i++)
7172 && vr_value[i]->type == VR_RANGE
7173 && vr_value[i]->min == vr_value[i]->max)
7175 single_val_range[i].value = vr_value[i]->min;
7176 do_value_subst_p = true;
7179 if (!do_value_subst_p)
7181 /* We found no single-valued ranges, don't waste time trying to
7182 do single value substitution in substitute_and_fold. */
7183 free (single_val_range);
7184 single_val_range = NULL;
7187 substitute_and_fold (single_val_range, true);
7189 if (warn_array_bounds)
7190 check_all_array_refs ();
7192 /* We must identify jump threading opportunities before we release
7193 the datastructures built by VRP. */
7194 identify_jump_threads ();
7196 /* Free allocated memory. */
7197 for (i = 0; i < num_ssa_names; i++)
7200 BITMAP_FREE (vr_value[i]->equiv);
7204 free (single_val_range);
7206 free (vr_phi_edge_counts);
7208 /* So that we can distinguish between VRP data being available
7209 and not available. */
7211 vr_phi_edge_counts = NULL;
7215 /* Main entry point to VRP (Value Range Propagation). This pass is
7216 loosely based on J. R. C. Patterson, ``Accurate Static Branch
7217 Prediction by Value Range Propagation,'' in SIGPLAN Conference on
7218 Programming Language Design and Implementation, pp. 67-78, 1995.
7219 Also available at http://citeseer.ist.psu.edu/patterson95accurate.html
7221 This is essentially an SSA-CCP pass modified to deal with ranges
7222 instead of constants.
7224 While propagating ranges, we may find that two or more SSA name
7225 have equivalent, though distinct ranges. For instance,
7228 2 p_4 = ASSERT_EXPR <p_3, p_3 != 0>
7230 4 p_5 = ASSERT_EXPR <p_4, p_4 == q_2>;
7234 In the code above, pointer p_5 has range [q_2, q_2], but from the
7235 code we can also determine that p_5 cannot be NULL and, if q_2 had
7236 a non-varying range, p_5's range should also be compatible with it.
7238 These equivalences are created by two expressions: ASSERT_EXPR and
7239 copy operations. Since p_5 is an assertion on p_4, and p_4 was the
7240 result of another assertion, then we can use the fact that p_5 and
7241 p_4 are equivalent when evaluating p_5's range.
7243 Together with value ranges, we also propagate these equivalences
7244 between names so that we can take advantage of information from
7245 multiple ranges when doing final replacement. Note that this
7246 equivalency relation is transitive but not symmetric.
7248 In the example above, p_5 is equivalent to p_4, q_2 and p_3, but we
7249 cannot assert that q_2 is equivalent to p_5 because q_2 may be used
7250 in contexts where that assertion does not hold (e.g., in line 6).
7252 TODO, the main difference between this pass and Patterson's is that
7253 we do not propagate edge probabilities. We only compute whether
7254 edges can be taken or not. That is, instead of having a spectrum
7255 of jump probabilities between 0 and 1, we only deal with 0, 1 and
7256 DON'T KNOW. In the future, it may be worthwhile to propagate
7257 probabilities to aid branch prediction. */
7266 loop_optimizer_init (LOOPS_NORMAL | LOOPS_HAVE_RECORDED_EXITS);
7267 rewrite_into_loop_closed_ssa (NULL, TODO_update_ssa);
7270 insert_range_assertions ();
7272 to_remove_edges = VEC_alloc (edge, heap, 10);
7273 to_update_switch_stmts = VEC_alloc (switch_update, heap, 5);
7276 ssa_propagate (vrp_visit_stmt, vrp_visit_phi_node);
7279 /* ASSERT_EXPRs must be removed before finalizing jump threads
7280 as finalizing jump threads calls the CFG cleanup code which
7281 does not properly handle ASSERT_EXPRs. */
7282 remove_range_assertions ();
7284 /* If we exposed any new variables, go ahead and put them into
7285 SSA form now, before we handle jump threading. This simplifies
7286 interactions between rewriting of _DECL nodes into SSA form
7287 and rewriting SSA_NAME nodes into SSA form after block
7288 duplication and CFG manipulation. */
7289 update_ssa (TODO_update_ssa);
7291 finalize_jump_threads ();
7293 /* Remove dead edges from SWITCH_EXPR optimization. This leaves the
7294 CFG in a broken state and requires a cfg_cleanup run. */
7295 for (i = 0; VEC_iterate (edge, to_remove_edges, i, e); ++i)
7297 /* Update SWITCH_EXPR case label vector. */
7298 for (i = 0; VEC_iterate (switch_update, to_update_switch_stmts, i, su); ++i)
7301 size_t n = TREE_VEC_LENGTH (su->vec);
7303 gimple_switch_set_num_labels (su->stmt, n);
7304 for (j = 0; j < n; j++)
7305 gimple_switch_set_label (su->stmt, j, TREE_VEC_ELT (su->vec, j));
7306 /* As we may have replaced the default label with a regular one
7307 make sure to make it a real default label again. This ensures
7308 optimal expansion. */
7309 label = gimple_switch_default_label (su->stmt);
7310 CASE_LOW (label) = NULL_TREE;
7311 CASE_HIGH (label) = NULL_TREE;
7314 if (VEC_length (edge, to_remove_edges) > 0)
7315 free_dominance_info (CDI_DOMINATORS);
7317 VEC_free (edge, heap, to_remove_edges);
7318 VEC_free (switch_update, heap, to_update_switch_stmts);
7321 loop_optimizer_finalize ();
7328 return flag_tree_vrp != 0;
7331 struct gimple_opt_pass pass_vrp =
7336 gate_vrp, /* gate */
7337 execute_vrp, /* execute */
7340 0, /* static_pass_number */
7341 TV_TREE_VRP, /* tv_id */
7342 PROP_ssa | PROP_alias, /* properties_required */
7343 0, /* properties_provided */
7344 0, /* properties_destroyed */
7345 0, /* todo_flags_start */
7350 | TODO_update_ssa /* todo_flags_finish */