1 /* Support routines for Value Range Propagation (VRP).
2 Copyright (C) 2005, 2006, 2007, 2008, 2009, 2010
3 Free Software Foundation, Inc.
4 Contributed by Diego Novillo <dnovillo@redhat.com>.
6 This file is part of GCC.
8 GCC is free software; you can redistribute it and/or modify
9 it under the terms of the GNU General Public License as published by
10 the Free Software Foundation; either version 3, or (at your option)
13 GCC is distributed in the hope that it will be useful,
14 but WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 GNU General Public License for more details.
18 You should have received a copy of the GNU General Public License
19 along with GCC; see the file COPYING3. If not see
20 <http://www.gnu.org/licenses/>. */
24 #include "coretypes.h"
29 #include "basic-block.h"
30 #include "tree-flow.h"
31 #include "tree-pass.h"
32 #include "tree-dump.h"
34 #include "tree-pretty-print.h"
35 #include "gimple-pretty-print.h"
39 #include "tree-scalar-evolution.h"
40 #include "tree-ssa-propagate.h"
41 #include "tree-chrec.h"
44 /* Set of SSA names found live during the RPO traversal of the function
45 for still active basic-blocks. */
48 /* Return true if the SSA name NAME is live on the edge E. */
51 live_on_edge (edge e, tree name)
53 return (live[e->dest->index]
54 && TEST_BIT (live[e->dest->index], SSA_NAME_VERSION (name)));
57 /* Local functions. */
58 static int compare_values (tree val1, tree val2);
59 static int compare_values_warnv (tree val1, tree val2, bool *);
60 static void vrp_meet (value_range_t *, value_range_t *);
61 static tree vrp_evaluate_conditional_warnv_with_ops (enum tree_code,
62 tree, tree, bool, bool *,
65 /* Location information for ASSERT_EXPRs. Each instance of this
66 structure describes an ASSERT_EXPR for an SSA name. Since a single
67 SSA name may have more than one assertion associated with it, these
68 locations are kept in a linked list attached to the corresponding
72 /* Basic block where the assertion would be inserted. */
75 /* Some assertions need to be inserted on an edge (e.g., assertions
76 generated by COND_EXPRs). In those cases, BB will be NULL. */
79 /* Pointer to the statement that generated this assertion. */
80 gimple_stmt_iterator si;
82 /* Predicate code for the ASSERT_EXPR. Must be COMPARISON_CLASS_P. */
83 enum tree_code comp_code;
85 /* Value being compared against. */
88 /* Expression to compare. */
91 /* Next node in the linked list. */
92 struct assert_locus_d *next;
95 typedef struct assert_locus_d *assert_locus_t;
97 /* If bit I is present, it means that SSA name N_i has a list of
98 assertions that should be inserted in the IL. */
99 static bitmap need_assert_for;
101 /* Array of locations lists where to insert assertions. ASSERTS_FOR[I]
102 holds a list of ASSERT_LOCUS_T nodes that describe where
103 ASSERT_EXPRs for SSA name N_I should be inserted. */
104 static assert_locus_t *asserts_for;
106 /* Value range array. After propagation, VR_VALUE[I] holds the range
107 of values that SSA name N_I may take. */
108 static value_range_t **vr_value;
110 /* For a PHI node which sets SSA name N_I, VR_COUNTS[I] holds the
111 number of executable edges we saw the last time we visited the
113 static int *vr_phi_edge_counts;
120 static VEC (edge, heap) *to_remove_edges;
121 DEF_VEC_O(switch_update);
122 DEF_VEC_ALLOC_O(switch_update, heap);
123 static VEC (switch_update, heap) *to_update_switch_stmts;
126 /* Return the maximum value for TYPE. */
129 vrp_val_max (const_tree type)
131 if (!INTEGRAL_TYPE_P (type))
134 return TYPE_MAX_VALUE (type);
137 /* Return the minimum value for TYPE. */
140 vrp_val_min (const_tree type)
142 if (!INTEGRAL_TYPE_P (type))
145 return TYPE_MIN_VALUE (type);
148 /* Return whether VAL is equal to the maximum value of its type. This
149 will be true for a positive overflow infinity. We can't do a
150 simple equality comparison with TYPE_MAX_VALUE because C typedefs
151 and Ada subtypes can produce types whose TYPE_MAX_VALUE is not ==
152 to the integer constant with the same value in the type. */
155 vrp_val_is_max (const_tree val)
157 tree type_max = vrp_val_max (TREE_TYPE (val));
158 return (val == type_max
159 || (type_max != NULL_TREE
160 && operand_equal_p (val, type_max, 0)));
163 /* Return whether VAL is equal to the minimum value of its type. This
164 will be true for a negative overflow infinity. */
167 vrp_val_is_min (const_tree val)
169 tree type_min = vrp_val_min (TREE_TYPE (val));
170 return (val == type_min
171 || (type_min != NULL_TREE
172 && operand_equal_p (val, type_min, 0)));
176 /* Return whether TYPE should use an overflow infinity distinct from
177 TYPE_{MIN,MAX}_VALUE. We use an overflow infinity value to
178 represent a signed overflow during VRP computations. An infinity
179 is distinct from a half-range, which will go from some number to
180 TYPE_{MIN,MAX}_VALUE. */
183 needs_overflow_infinity (const_tree type)
185 return INTEGRAL_TYPE_P (type) && !TYPE_OVERFLOW_WRAPS (type);
188 /* Return whether TYPE can support our overflow infinity
189 representation: we use the TREE_OVERFLOW flag, which only exists
190 for constants. If TYPE doesn't support this, we don't optimize
191 cases which would require signed overflow--we drop them to
195 supports_overflow_infinity (const_tree type)
197 tree min = vrp_val_min (type), max = vrp_val_max (type);
198 #ifdef ENABLE_CHECKING
199 gcc_assert (needs_overflow_infinity (type));
201 return (min != NULL_TREE
202 && CONSTANT_CLASS_P (min)
204 && CONSTANT_CLASS_P (max));
207 /* VAL is the maximum or minimum value of a type. Return a
208 corresponding overflow infinity. */
211 make_overflow_infinity (tree val)
213 #ifdef ENABLE_CHECKING
214 gcc_assert (val != NULL_TREE && CONSTANT_CLASS_P (val));
216 val = copy_node (val);
217 TREE_OVERFLOW (val) = 1;
221 /* Return a negative overflow infinity for TYPE. */
224 negative_overflow_infinity (tree type)
226 #ifdef ENABLE_CHECKING
227 gcc_assert (supports_overflow_infinity (type));
229 return make_overflow_infinity (vrp_val_min (type));
232 /* Return a positive overflow infinity for TYPE. */
235 positive_overflow_infinity (tree type)
237 #ifdef ENABLE_CHECKING
238 gcc_assert (supports_overflow_infinity (type));
240 return make_overflow_infinity (vrp_val_max (type));
243 /* Return whether VAL is a negative overflow infinity. */
246 is_negative_overflow_infinity (const_tree val)
248 return (needs_overflow_infinity (TREE_TYPE (val))
249 && CONSTANT_CLASS_P (val)
250 && TREE_OVERFLOW (val)
251 && vrp_val_is_min (val));
254 /* Return whether VAL is a positive overflow infinity. */
257 is_positive_overflow_infinity (const_tree val)
259 return (needs_overflow_infinity (TREE_TYPE (val))
260 && CONSTANT_CLASS_P (val)
261 && TREE_OVERFLOW (val)
262 && vrp_val_is_max (val));
265 /* Return whether VAL is a positive or negative overflow infinity. */
268 is_overflow_infinity (const_tree val)
270 return (needs_overflow_infinity (TREE_TYPE (val))
271 && CONSTANT_CLASS_P (val)
272 && TREE_OVERFLOW (val)
273 && (vrp_val_is_min (val) || vrp_val_is_max (val)));
276 /* Return whether STMT has a constant rhs that is_overflow_infinity. */
279 stmt_overflow_infinity (gimple stmt)
281 if (is_gimple_assign (stmt)
282 && get_gimple_rhs_class (gimple_assign_rhs_code (stmt)) ==
284 return is_overflow_infinity (gimple_assign_rhs1 (stmt));
288 /* If VAL is now an overflow infinity, return VAL. Otherwise, return
289 the same value with TREE_OVERFLOW clear. This can be used to avoid
290 confusing a regular value with an overflow value. */
293 avoid_overflow_infinity (tree val)
295 if (!is_overflow_infinity (val))
298 if (vrp_val_is_max (val))
299 return vrp_val_max (TREE_TYPE (val));
302 #ifdef ENABLE_CHECKING
303 gcc_assert (vrp_val_is_min (val));
305 return vrp_val_min (TREE_TYPE (val));
310 /* Return true if ARG is marked with the nonnull attribute in the
311 current function signature. */
314 nonnull_arg_p (const_tree arg)
316 tree t, attrs, fntype;
317 unsigned HOST_WIDE_INT arg_num;
319 gcc_assert (TREE_CODE (arg) == PARM_DECL && POINTER_TYPE_P (TREE_TYPE (arg)));
321 /* The static chain decl is always non null. */
322 if (arg == cfun->static_chain_decl)
325 fntype = TREE_TYPE (current_function_decl);
326 attrs = lookup_attribute ("nonnull", TYPE_ATTRIBUTES (fntype));
328 /* If "nonnull" wasn't specified, we know nothing about the argument. */
329 if (attrs == NULL_TREE)
332 /* If "nonnull" applies to all the arguments, then ARG is non-null. */
333 if (TREE_VALUE (attrs) == NULL_TREE)
336 /* Get the position number for ARG in the function signature. */
337 for (arg_num = 1, t = DECL_ARGUMENTS (current_function_decl);
339 t = TREE_CHAIN (t), arg_num++)
345 gcc_assert (t == arg);
347 /* Now see if ARG_NUM is mentioned in the nonnull list. */
348 for (t = TREE_VALUE (attrs); t; t = TREE_CHAIN (t))
350 if (compare_tree_int (TREE_VALUE (t), arg_num) == 0)
358 /* Set value range VR to VR_VARYING. */
361 set_value_range_to_varying (value_range_t *vr)
363 vr->type = VR_VARYING;
364 vr->min = vr->max = NULL_TREE;
366 bitmap_clear (vr->equiv);
370 /* Set value range VR to {T, MIN, MAX, EQUIV}. */
373 set_value_range (value_range_t *vr, enum value_range_type t, tree min,
374 tree max, bitmap equiv)
376 #if defined ENABLE_CHECKING
377 /* Check the validity of the range. */
378 if (t == VR_RANGE || t == VR_ANTI_RANGE)
382 gcc_assert (min && max);
384 if (INTEGRAL_TYPE_P (TREE_TYPE (min)) && t == VR_ANTI_RANGE)
385 gcc_assert (!vrp_val_is_min (min) || !vrp_val_is_max (max));
387 cmp = compare_values (min, max);
388 gcc_assert (cmp == 0 || cmp == -1 || cmp == -2);
390 if (needs_overflow_infinity (TREE_TYPE (min)))
391 gcc_assert (!is_overflow_infinity (min)
392 || !is_overflow_infinity (max));
395 if (t == VR_UNDEFINED || t == VR_VARYING)
396 gcc_assert (min == NULL_TREE && max == NULL_TREE);
398 if (t == VR_UNDEFINED || t == VR_VARYING)
399 gcc_assert (equiv == NULL || bitmap_empty_p (equiv));
406 /* Since updating the equivalence set involves deep copying the
407 bitmaps, only do it if absolutely necessary. */
408 if (vr->equiv == NULL
410 vr->equiv = BITMAP_ALLOC (NULL);
412 if (equiv != vr->equiv)
414 if (equiv && !bitmap_empty_p (equiv))
415 bitmap_copy (vr->equiv, equiv);
417 bitmap_clear (vr->equiv);
422 /* Set value range VR to the canonical form of {T, MIN, MAX, EQUIV}.
423 This means adjusting T, MIN and MAX representing the case of a
424 wrapping range with MAX < MIN covering [MIN, type_max] U [type_min, MAX]
425 as anti-rage ~[MAX+1, MIN-1]. Likewise for wrapping anti-ranges.
426 In corner cases where MAX+1 or MIN-1 wraps this will fall back
428 This routine exists to ease canonicalization in the case where we
429 extract ranges from var + CST op limit. */
432 set_and_canonicalize_value_range (value_range_t *vr, enum value_range_type t,
433 tree min, tree max, bitmap equiv)
435 /* Nothing to canonicalize for symbolic or unknown or varying ranges. */
437 && t != VR_ANTI_RANGE)
438 || TREE_CODE (min) != INTEGER_CST
439 || TREE_CODE (max) != INTEGER_CST)
441 set_value_range (vr, t, min, max, equiv);
445 /* Wrong order for min and max, to swap them and the VR type we need
447 if (tree_int_cst_lt (max, min))
449 tree one = build_int_cst (TREE_TYPE (min), 1);
450 tree tmp = int_const_binop (PLUS_EXPR, max, one, 0);
451 max = int_const_binop (MINUS_EXPR, min, one, 0);
454 /* There's one corner case, if we had [C+1, C] before we now have
455 that again. But this represents an empty value range, so drop
456 to varying in this case. */
457 if (tree_int_cst_lt (max, min))
459 set_value_range_to_varying (vr);
463 t = t == VR_RANGE ? VR_ANTI_RANGE : VR_RANGE;
466 /* Anti-ranges that can be represented as ranges should be so. */
467 if (t == VR_ANTI_RANGE)
469 bool is_min = vrp_val_is_min (min);
470 bool is_max = vrp_val_is_max (max);
472 if (is_min && is_max)
474 /* We cannot deal with empty ranges, drop to varying. */
475 set_value_range_to_varying (vr);
479 /* As a special exception preserve non-null ranges. */
480 && !(TYPE_UNSIGNED (TREE_TYPE (min))
481 && integer_zerop (max)))
483 tree one = build_int_cst (TREE_TYPE (max), 1);
484 min = int_const_binop (PLUS_EXPR, max, one, 0);
485 max = vrp_val_max (TREE_TYPE (max));
490 tree one = build_int_cst (TREE_TYPE (min), 1);
491 max = int_const_binop (MINUS_EXPR, min, one, 0);
492 min = vrp_val_min (TREE_TYPE (min));
497 set_value_range (vr, t, min, max, equiv);
500 /* Copy value range FROM into value range TO. */
503 copy_value_range (value_range_t *to, value_range_t *from)
505 set_value_range (to, from->type, from->min, from->max, from->equiv);
508 /* Set value range VR to a single value. This function is only called
509 with values we get from statements, and exists to clear the
510 TREE_OVERFLOW flag so that we don't think we have an overflow
511 infinity when we shouldn't. */
514 set_value_range_to_value (value_range_t *vr, tree val, bitmap equiv)
516 gcc_assert (is_gimple_min_invariant (val));
517 val = avoid_overflow_infinity (val);
518 set_value_range (vr, VR_RANGE, val, val, equiv);
521 /* Set value range VR to a non-negative range of type TYPE.
522 OVERFLOW_INFINITY indicates whether to use an overflow infinity
523 rather than TYPE_MAX_VALUE; this should be true if we determine
524 that the range is nonnegative based on the assumption that signed
525 overflow does not occur. */
528 set_value_range_to_nonnegative (value_range_t *vr, tree type,
529 bool overflow_infinity)
533 if (overflow_infinity && !supports_overflow_infinity (type))
535 set_value_range_to_varying (vr);
539 zero = build_int_cst (type, 0);
540 set_value_range (vr, VR_RANGE, zero,
542 ? positive_overflow_infinity (type)
543 : TYPE_MAX_VALUE (type)),
547 /* Set value range VR to a non-NULL range of type TYPE. */
550 set_value_range_to_nonnull (value_range_t *vr, tree type)
552 tree zero = build_int_cst (type, 0);
553 set_value_range (vr, VR_ANTI_RANGE, zero, zero, vr->equiv);
557 /* Set value range VR to a NULL range of type TYPE. */
560 set_value_range_to_null (value_range_t *vr, tree type)
562 set_value_range_to_value (vr, build_int_cst (type, 0), vr->equiv);
566 /* Set value range VR to a range of a truthvalue of type TYPE. */
569 set_value_range_to_truthvalue (value_range_t *vr, tree type)
571 if (TYPE_PRECISION (type) == 1)
572 set_value_range_to_varying (vr);
574 set_value_range (vr, VR_RANGE,
575 build_int_cst (type, 0), build_int_cst (type, 1),
580 /* Set value range VR to VR_UNDEFINED. */
583 set_value_range_to_undefined (value_range_t *vr)
585 vr->type = VR_UNDEFINED;
586 vr->min = vr->max = NULL_TREE;
588 bitmap_clear (vr->equiv);
592 /* If abs (min) < abs (max), set VR to [-max, max], if
593 abs (min) >= abs (max), set VR to [-min, min]. */
596 abs_extent_range (value_range_t *vr, tree min, tree max)
600 gcc_assert (TREE_CODE (min) == INTEGER_CST);
601 gcc_assert (TREE_CODE (max) == INTEGER_CST);
602 gcc_assert (INTEGRAL_TYPE_P (TREE_TYPE (min)));
603 gcc_assert (!TYPE_UNSIGNED (TREE_TYPE (min)));
604 min = fold_unary (ABS_EXPR, TREE_TYPE (min), min);
605 max = fold_unary (ABS_EXPR, TREE_TYPE (max), max);
606 if (TREE_OVERFLOW (min) || TREE_OVERFLOW (max))
608 set_value_range_to_varying (vr);
611 cmp = compare_values (min, max);
613 min = fold_unary (NEGATE_EXPR, TREE_TYPE (min), max);
614 else if (cmp == 0 || cmp == 1)
617 min = fold_unary (NEGATE_EXPR, TREE_TYPE (min), min);
621 set_value_range_to_varying (vr);
624 set_and_canonicalize_value_range (vr, VR_RANGE, min, max, NULL);
628 /* Return value range information for VAR.
630 If we have no values ranges recorded (ie, VRP is not running), then
631 return NULL. Otherwise create an empty range if none existed for VAR. */
633 static value_range_t *
634 get_value_range (const_tree var)
638 unsigned ver = SSA_NAME_VERSION (var);
640 /* If we have no recorded ranges, then return NULL. */
648 /* Create a default value range. */
649 vr_value[ver] = vr = XCNEW (value_range_t);
651 /* Defer allocating the equivalence set. */
654 /* If VAR is a default definition, the variable can take any value
656 sym = SSA_NAME_VAR (var);
657 if (SSA_NAME_IS_DEFAULT_DEF (var))
659 /* Try to use the "nonnull" attribute to create ~[0, 0]
660 anti-ranges for pointers. Note that this is only valid with
661 default definitions of PARM_DECLs. */
662 if (TREE_CODE (sym) == PARM_DECL
663 && POINTER_TYPE_P (TREE_TYPE (sym))
664 && nonnull_arg_p (sym))
665 set_value_range_to_nonnull (vr, TREE_TYPE (sym));
667 set_value_range_to_varying (vr);
673 /* Return true, if VAL1 and VAL2 are equal values for VRP purposes. */
676 vrp_operand_equal_p (const_tree val1, const_tree val2)
680 if (!val1 || !val2 || !operand_equal_p (val1, val2, 0))
682 if (is_overflow_infinity (val1))
683 return is_overflow_infinity (val2);
687 /* Return true, if the bitmaps B1 and B2 are equal. */
690 vrp_bitmap_equal_p (const_bitmap b1, const_bitmap b2)
694 && bitmap_equal_p (b1, b2)));
697 /* Update the value range and equivalence set for variable VAR to
698 NEW_VR. Return true if NEW_VR is different from VAR's previous
701 NOTE: This function assumes that NEW_VR is a temporary value range
702 object created for the sole purpose of updating VAR's range. The
703 storage used by the equivalence set from NEW_VR will be freed by
704 this function. Do not call update_value_range when NEW_VR
705 is the range object associated with another SSA name. */
708 update_value_range (const_tree var, value_range_t *new_vr)
710 value_range_t *old_vr;
713 /* Update the value range, if necessary. */
714 old_vr = get_value_range (var);
715 is_new = old_vr->type != new_vr->type
716 || !vrp_operand_equal_p (old_vr->min, new_vr->min)
717 || !vrp_operand_equal_p (old_vr->max, new_vr->max)
718 || !vrp_bitmap_equal_p (old_vr->equiv, new_vr->equiv);
721 set_value_range (old_vr, new_vr->type, new_vr->min, new_vr->max,
724 BITMAP_FREE (new_vr->equiv);
730 /* Add VAR and VAR's equivalence set to EQUIV. This is the central
731 point where equivalence processing can be turned on/off. */
734 add_equivalence (bitmap *equiv, const_tree var)
736 unsigned ver = SSA_NAME_VERSION (var);
737 value_range_t *vr = vr_value[ver];
740 *equiv = BITMAP_ALLOC (NULL);
741 bitmap_set_bit (*equiv, ver);
743 bitmap_ior_into (*equiv, vr->equiv);
747 /* Return true if VR is ~[0, 0]. */
750 range_is_nonnull (value_range_t *vr)
752 return vr->type == VR_ANTI_RANGE
753 && integer_zerop (vr->min)
754 && integer_zerop (vr->max);
758 /* Return true if VR is [0, 0]. */
761 range_is_null (value_range_t *vr)
763 return vr->type == VR_RANGE
764 && integer_zerop (vr->min)
765 && integer_zerop (vr->max);
768 /* Return true if max and min of VR are INTEGER_CST. It's not necessary
772 range_int_cst_p (value_range_t *vr)
774 return (vr->type == VR_RANGE
775 && TREE_CODE (vr->max) == INTEGER_CST
776 && TREE_CODE (vr->min) == INTEGER_CST
777 && !TREE_OVERFLOW (vr->max)
778 && !TREE_OVERFLOW (vr->min));
781 /* Return true if VR is a INTEGER_CST singleton. */
784 range_int_cst_singleton_p (value_range_t *vr)
786 return (range_int_cst_p (vr)
787 && tree_int_cst_equal (vr->min, vr->max));
790 /* Return true if value range VR involves at least one symbol. */
793 symbolic_range_p (value_range_t *vr)
795 return (!is_gimple_min_invariant (vr->min)
796 || !is_gimple_min_invariant (vr->max));
799 /* Return true if value range VR uses an overflow infinity. */
802 overflow_infinity_range_p (value_range_t *vr)
804 return (vr->type == VR_RANGE
805 && (is_overflow_infinity (vr->min)
806 || is_overflow_infinity (vr->max)));
809 /* Return false if we can not make a valid comparison based on VR;
810 this will be the case if it uses an overflow infinity and overflow
811 is not undefined (i.e., -fno-strict-overflow is in effect).
812 Otherwise return true, and set *STRICT_OVERFLOW_P to true if VR
813 uses an overflow infinity. */
816 usable_range_p (value_range_t *vr, bool *strict_overflow_p)
818 gcc_assert (vr->type == VR_RANGE);
819 if (is_overflow_infinity (vr->min))
821 *strict_overflow_p = true;
822 if (!TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (vr->min)))
825 if (is_overflow_infinity (vr->max))
827 *strict_overflow_p = true;
828 if (!TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (vr->max)))
835 /* Like tree_expr_nonnegative_warnv_p, but this function uses value
836 ranges obtained so far. */
839 vrp_expr_computes_nonnegative (tree expr, bool *strict_overflow_p)
841 return (tree_expr_nonnegative_warnv_p (expr, strict_overflow_p)
842 || (TREE_CODE (expr) == SSA_NAME
843 && ssa_name_nonnegative_p (expr)));
846 /* Return true if the result of assignment STMT is know to be non-negative.
847 If the return value is based on the assumption that signed overflow is
848 undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't change
849 *STRICT_OVERFLOW_P.*/
852 gimple_assign_nonnegative_warnv_p (gimple stmt, bool *strict_overflow_p)
854 enum tree_code code = gimple_assign_rhs_code (stmt);
855 switch (get_gimple_rhs_class (code))
857 case GIMPLE_UNARY_RHS:
858 return tree_unary_nonnegative_warnv_p (gimple_assign_rhs_code (stmt),
859 gimple_expr_type (stmt),
860 gimple_assign_rhs1 (stmt),
862 case GIMPLE_BINARY_RHS:
863 return tree_binary_nonnegative_warnv_p (gimple_assign_rhs_code (stmt),
864 gimple_expr_type (stmt),
865 gimple_assign_rhs1 (stmt),
866 gimple_assign_rhs2 (stmt),
868 case GIMPLE_TERNARY_RHS:
870 case GIMPLE_SINGLE_RHS:
871 return tree_single_nonnegative_warnv_p (gimple_assign_rhs1 (stmt),
873 case GIMPLE_INVALID_RHS:
880 /* Return true if return value of call STMT is know to be non-negative.
881 If the return value is based on the assumption that signed overflow is
882 undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't change
883 *STRICT_OVERFLOW_P.*/
886 gimple_call_nonnegative_warnv_p (gimple stmt, bool *strict_overflow_p)
888 tree arg0 = gimple_call_num_args (stmt) > 0 ?
889 gimple_call_arg (stmt, 0) : NULL_TREE;
890 tree arg1 = gimple_call_num_args (stmt) > 1 ?
891 gimple_call_arg (stmt, 1) : NULL_TREE;
893 return tree_call_nonnegative_warnv_p (gimple_expr_type (stmt),
894 gimple_call_fndecl (stmt),
900 /* Return true if STMT is know to to compute a non-negative value.
901 If the return value is based on the assumption that signed overflow is
902 undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't change
903 *STRICT_OVERFLOW_P.*/
906 gimple_stmt_nonnegative_warnv_p (gimple stmt, bool *strict_overflow_p)
908 switch (gimple_code (stmt))
911 return gimple_assign_nonnegative_warnv_p (stmt, strict_overflow_p);
913 return gimple_call_nonnegative_warnv_p (stmt, strict_overflow_p);
919 /* Return true if the result of assignment STMT is know to be non-zero.
920 If the return value is based on the assumption that signed overflow is
921 undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't change
922 *STRICT_OVERFLOW_P.*/
925 gimple_assign_nonzero_warnv_p (gimple stmt, bool *strict_overflow_p)
927 enum tree_code code = gimple_assign_rhs_code (stmt);
928 switch (get_gimple_rhs_class (code))
930 case GIMPLE_UNARY_RHS:
931 return tree_unary_nonzero_warnv_p (gimple_assign_rhs_code (stmt),
932 gimple_expr_type (stmt),
933 gimple_assign_rhs1 (stmt),
935 case GIMPLE_BINARY_RHS:
936 return tree_binary_nonzero_warnv_p (gimple_assign_rhs_code (stmt),
937 gimple_expr_type (stmt),
938 gimple_assign_rhs1 (stmt),
939 gimple_assign_rhs2 (stmt),
941 case GIMPLE_TERNARY_RHS:
943 case GIMPLE_SINGLE_RHS:
944 return tree_single_nonzero_warnv_p (gimple_assign_rhs1 (stmt),
946 case GIMPLE_INVALID_RHS:
953 /* Return true if STMT is know to to compute a non-zero value.
954 If the return value is based on the assumption that signed overflow is
955 undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't change
956 *STRICT_OVERFLOW_P.*/
959 gimple_stmt_nonzero_warnv_p (gimple stmt, bool *strict_overflow_p)
961 switch (gimple_code (stmt))
964 return gimple_assign_nonzero_warnv_p (stmt, strict_overflow_p);
966 return gimple_alloca_call_p (stmt);
972 /* Like tree_expr_nonzero_warnv_p, but this function uses value ranges
976 vrp_stmt_computes_nonzero (gimple stmt, bool *strict_overflow_p)
978 if (gimple_stmt_nonzero_warnv_p (stmt, strict_overflow_p))
981 /* If we have an expression of the form &X->a, then the expression
982 is nonnull if X is nonnull. */
983 if (is_gimple_assign (stmt)
984 && gimple_assign_rhs_code (stmt) == ADDR_EXPR)
986 tree expr = gimple_assign_rhs1 (stmt);
987 tree base = get_base_address (TREE_OPERAND (expr, 0));
989 if (base != NULL_TREE
990 && TREE_CODE (base) == INDIRECT_REF
991 && TREE_CODE (TREE_OPERAND (base, 0)) == SSA_NAME)
993 value_range_t *vr = get_value_range (TREE_OPERAND (base, 0));
994 if (range_is_nonnull (vr))
1002 /* Returns true if EXPR is a valid value (as expected by compare_values) --
1003 a gimple invariant, or SSA_NAME +- CST. */
1006 valid_value_p (tree expr)
1008 if (TREE_CODE (expr) == SSA_NAME)
1011 if (TREE_CODE (expr) == PLUS_EXPR
1012 || TREE_CODE (expr) == MINUS_EXPR)
1013 return (TREE_CODE (TREE_OPERAND (expr, 0)) == SSA_NAME
1014 && TREE_CODE (TREE_OPERAND (expr, 1)) == INTEGER_CST);
1016 return is_gimple_min_invariant (expr);
1022 -2 if those are incomparable. */
1024 operand_less_p (tree val, tree val2)
1026 /* LT is folded faster than GE and others. Inline the common case. */
1027 if (TREE_CODE (val) == INTEGER_CST && TREE_CODE (val2) == INTEGER_CST)
1029 if (TYPE_UNSIGNED (TREE_TYPE (val)))
1030 return INT_CST_LT_UNSIGNED (val, val2);
1033 if (INT_CST_LT (val, val2))
1041 fold_defer_overflow_warnings ();
1043 tcmp = fold_binary_to_constant (LT_EXPR, boolean_type_node, val, val2);
1045 fold_undefer_and_ignore_overflow_warnings ();
1048 || TREE_CODE (tcmp) != INTEGER_CST)
1051 if (!integer_zerop (tcmp))
1055 /* val >= val2, not considering overflow infinity. */
1056 if (is_negative_overflow_infinity (val))
1057 return is_negative_overflow_infinity (val2) ? 0 : 1;
1058 else if (is_positive_overflow_infinity (val2))
1059 return is_positive_overflow_infinity (val) ? 0 : 1;
1064 /* Compare two values VAL1 and VAL2. Return
1066 -2 if VAL1 and VAL2 cannot be compared at compile-time,
1069 +1 if VAL1 > VAL2, and
1072 This is similar to tree_int_cst_compare but supports pointer values
1073 and values that cannot be compared at compile time.
1075 If STRICT_OVERFLOW_P is not NULL, then set *STRICT_OVERFLOW_P to
1076 true if the return value is only valid if we assume that signed
1077 overflow is undefined. */
1080 compare_values_warnv (tree val1, tree val2, bool *strict_overflow_p)
1085 /* Below we rely on the fact that VAL1 and VAL2 are both pointers or
1087 gcc_assert (POINTER_TYPE_P (TREE_TYPE (val1))
1088 == POINTER_TYPE_P (TREE_TYPE (val2)));
1089 /* Convert the two values into the same type. This is needed because
1090 sizetype causes sign extension even for unsigned types. */
1091 val2 = fold_convert (TREE_TYPE (val1), val2);
1092 STRIP_USELESS_TYPE_CONVERSION (val2);
1094 if ((TREE_CODE (val1) == SSA_NAME
1095 || TREE_CODE (val1) == PLUS_EXPR
1096 || TREE_CODE (val1) == MINUS_EXPR)
1097 && (TREE_CODE (val2) == SSA_NAME
1098 || TREE_CODE (val2) == PLUS_EXPR
1099 || TREE_CODE (val2) == MINUS_EXPR))
1101 tree n1, c1, n2, c2;
1102 enum tree_code code1, code2;
1104 /* If VAL1 and VAL2 are of the form 'NAME [+-] CST' or 'NAME',
1105 return -1 or +1 accordingly. If VAL1 and VAL2 don't use the
1106 same name, return -2. */
1107 if (TREE_CODE (val1) == SSA_NAME)
1115 code1 = TREE_CODE (val1);
1116 n1 = TREE_OPERAND (val1, 0);
1117 c1 = TREE_OPERAND (val1, 1);
1118 if (tree_int_cst_sgn (c1) == -1)
1120 if (is_negative_overflow_infinity (c1))
1122 c1 = fold_unary_to_constant (NEGATE_EXPR, TREE_TYPE (c1), c1);
1125 code1 = code1 == MINUS_EXPR ? PLUS_EXPR : MINUS_EXPR;
1129 if (TREE_CODE (val2) == SSA_NAME)
1137 code2 = TREE_CODE (val2);
1138 n2 = TREE_OPERAND (val2, 0);
1139 c2 = TREE_OPERAND (val2, 1);
1140 if (tree_int_cst_sgn (c2) == -1)
1142 if (is_negative_overflow_infinity (c2))
1144 c2 = fold_unary_to_constant (NEGATE_EXPR, TREE_TYPE (c2), c2);
1147 code2 = code2 == MINUS_EXPR ? PLUS_EXPR : MINUS_EXPR;
1151 /* Both values must use the same name. */
1155 if (code1 == SSA_NAME
1156 && code2 == SSA_NAME)
1160 /* If overflow is defined we cannot simplify more. */
1161 if (!TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (val1)))
1164 if (strict_overflow_p != NULL
1165 && (code1 == SSA_NAME || !TREE_NO_WARNING (val1))
1166 && (code2 == SSA_NAME || !TREE_NO_WARNING (val2)))
1167 *strict_overflow_p = true;
1169 if (code1 == SSA_NAME)
1171 if (code2 == PLUS_EXPR)
1172 /* NAME < NAME + CST */
1174 else if (code2 == MINUS_EXPR)
1175 /* NAME > NAME - CST */
1178 else if (code1 == PLUS_EXPR)
1180 if (code2 == SSA_NAME)
1181 /* NAME + CST > NAME */
1183 else if (code2 == PLUS_EXPR)
1184 /* NAME + CST1 > NAME + CST2, if CST1 > CST2 */
1185 return compare_values_warnv (c1, c2, strict_overflow_p);
1186 else if (code2 == MINUS_EXPR)
1187 /* NAME + CST1 > NAME - CST2 */
1190 else if (code1 == MINUS_EXPR)
1192 if (code2 == SSA_NAME)
1193 /* NAME - CST < NAME */
1195 else if (code2 == PLUS_EXPR)
1196 /* NAME - CST1 < NAME + CST2 */
1198 else if (code2 == MINUS_EXPR)
1199 /* NAME - CST1 > NAME - CST2, if CST1 < CST2. Notice that
1200 C1 and C2 are swapped in the call to compare_values. */
1201 return compare_values_warnv (c2, c1, strict_overflow_p);
1207 /* We cannot compare non-constants. */
1208 if (!is_gimple_min_invariant (val1) || !is_gimple_min_invariant (val2))
1211 if (!POINTER_TYPE_P (TREE_TYPE (val1)))
1213 /* We cannot compare overflowed values, except for overflow
1215 if (TREE_OVERFLOW (val1) || TREE_OVERFLOW (val2))
1217 if (strict_overflow_p != NULL)
1218 *strict_overflow_p = true;
1219 if (is_negative_overflow_infinity (val1))
1220 return is_negative_overflow_infinity (val2) ? 0 : -1;
1221 else if (is_negative_overflow_infinity (val2))
1223 else if (is_positive_overflow_infinity (val1))
1224 return is_positive_overflow_infinity (val2) ? 0 : 1;
1225 else if (is_positive_overflow_infinity (val2))
1230 return tree_int_cst_compare (val1, val2);
1236 /* First see if VAL1 and VAL2 are not the same. */
1237 if (val1 == val2 || operand_equal_p (val1, val2, 0))
1240 /* If VAL1 is a lower address than VAL2, return -1. */
1241 if (operand_less_p (val1, val2) == 1)
1244 /* If VAL1 is a higher address than VAL2, return +1. */
1245 if (operand_less_p (val2, val1) == 1)
1248 /* If VAL1 is different than VAL2, return +2.
1249 For integer constants we either have already returned -1 or 1
1250 or they are equivalent. We still might succeed in proving
1251 something about non-trivial operands. */
1252 if (TREE_CODE (val1) != INTEGER_CST
1253 || TREE_CODE (val2) != INTEGER_CST)
1255 t = fold_binary_to_constant (NE_EXPR, boolean_type_node, val1, val2);
1256 if (t && integer_onep (t))
1264 /* Compare values like compare_values_warnv, but treat comparisons of
1265 nonconstants which rely on undefined overflow as incomparable. */
1268 compare_values (tree val1, tree val2)
1274 ret = compare_values_warnv (val1, val2, &sop);
1276 && (!is_gimple_min_invariant (val1) || !is_gimple_min_invariant (val2)))
1282 /* Return 1 if VAL is inside value range VR (VR->MIN <= VAL <= VR->MAX),
1283 0 if VAL is not inside VR,
1284 -2 if we cannot tell either way.
1286 FIXME, the current semantics of this functions are a bit quirky
1287 when taken in the context of VRP. In here we do not care
1288 about VR's type. If VR is the anti-range ~[3, 5] the call
1289 value_inside_range (4, VR) will return 1.
1291 This is counter-intuitive in a strict sense, but the callers
1292 currently expect this. They are calling the function
1293 merely to determine whether VR->MIN <= VAL <= VR->MAX. The
1294 callers are applying the VR_RANGE/VR_ANTI_RANGE semantics
1297 This also applies to value_ranges_intersect_p and
1298 range_includes_zero_p. The semantics of VR_RANGE and
1299 VR_ANTI_RANGE should be encoded here, but that also means
1300 adapting the users of these functions to the new semantics.
1302 Benchmark compile/20001226-1.c compilation time after changing this
1306 value_inside_range (tree val, value_range_t * vr)
1310 cmp1 = operand_less_p (val, vr->min);
1316 cmp2 = operand_less_p (vr->max, val);
1324 /* Return true if value ranges VR0 and VR1 have a non-empty
1327 Benchmark compile/20001226-1.c compilation time after changing this
1332 value_ranges_intersect_p (value_range_t *vr0, value_range_t *vr1)
1334 /* The value ranges do not intersect if the maximum of the first range is
1335 less than the minimum of the second range or vice versa.
1336 When those relations are unknown, we can't do any better. */
1337 if (operand_less_p (vr0->max, vr1->min) != 0)
1339 if (operand_less_p (vr1->max, vr0->min) != 0)
1345 /* Return true if VR includes the value zero, false otherwise. FIXME,
1346 currently this will return false for an anti-range like ~[-4, 3].
1347 This will be wrong when the semantics of value_inside_range are
1348 modified (currently the users of this function expect these
1352 range_includes_zero_p (value_range_t *vr)
1356 gcc_assert (vr->type != VR_UNDEFINED
1357 && vr->type != VR_VARYING
1358 && !symbolic_range_p (vr));
1360 zero = build_int_cst (TREE_TYPE (vr->min), 0);
1361 return (value_inside_range (zero, vr) == 1);
1364 /* Return true if T, an SSA_NAME, is known to be nonnegative. Return
1365 false otherwise or if no value range information is available. */
1368 ssa_name_nonnegative_p (const_tree t)
1370 value_range_t *vr = get_value_range (t);
1372 if (INTEGRAL_TYPE_P (t)
1373 && TYPE_UNSIGNED (t))
1379 /* Testing for VR_ANTI_RANGE is not useful here as any anti-range
1380 which would return a useful value should be encoded as a VR_RANGE. */
1381 if (vr->type == VR_RANGE)
1383 int result = compare_values (vr->min, integer_zero_node);
1385 return (result == 0 || result == 1);
1390 /* If OP has a value range with a single constant value return that,
1391 otherwise return NULL_TREE. This returns OP itself if OP is a
1395 op_with_constant_singleton_value_range (tree op)
1399 if (is_gimple_min_invariant (op))
1402 if (TREE_CODE (op) != SSA_NAME)
1405 vr = get_value_range (op);
1406 if (vr->type == VR_RANGE
1407 && operand_equal_p (vr->min, vr->max, 0)
1408 && is_gimple_min_invariant (vr->min))
1415 /* Extract value range information from an ASSERT_EXPR EXPR and store
1419 extract_range_from_assert (value_range_t *vr_p, tree expr)
1421 tree var, cond, limit, min, max, type;
1422 value_range_t *var_vr, *limit_vr;
1423 enum tree_code cond_code;
1425 var = ASSERT_EXPR_VAR (expr);
1426 cond = ASSERT_EXPR_COND (expr);
1428 gcc_assert (COMPARISON_CLASS_P (cond));
1430 /* Find VAR in the ASSERT_EXPR conditional. */
1431 if (var == TREE_OPERAND (cond, 0)
1432 || TREE_CODE (TREE_OPERAND (cond, 0)) == PLUS_EXPR
1433 || TREE_CODE (TREE_OPERAND (cond, 0)) == NOP_EXPR)
1435 /* If the predicate is of the form VAR COMP LIMIT, then we just
1436 take LIMIT from the RHS and use the same comparison code. */
1437 cond_code = TREE_CODE (cond);
1438 limit = TREE_OPERAND (cond, 1);
1439 cond = TREE_OPERAND (cond, 0);
1443 /* If the predicate is of the form LIMIT COMP VAR, then we need
1444 to flip around the comparison code to create the proper range
1446 cond_code = swap_tree_comparison (TREE_CODE (cond));
1447 limit = TREE_OPERAND (cond, 0);
1448 cond = TREE_OPERAND (cond, 1);
1451 limit = avoid_overflow_infinity (limit);
1453 type = TREE_TYPE (limit);
1454 gcc_assert (limit != var);
1456 /* For pointer arithmetic, we only keep track of pointer equality
1458 if (POINTER_TYPE_P (type) && cond_code != NE_EXPR && cond_code != EQ_EXPR)
1460 set_value_range_to_varying (vr_p);
1464 /* If LIMIT is another SSA name and LIMIT has a range of its own,
1465 try to use LIMIT's range to avoid creating symbolic ranges
1467 limit_vr = (TREE_CODE (limit) == SSA_NAME) ? get_value_range (limit) : NULL;
1469 /* LIMIT's range is only interesting if it has any useful information. */
1471 && (limit_vr->type == VR_UNDEFINED
1472 || limit_vr->type == VR_VARYING
1473 || symbolic_range_p (limit_vr)))
1476 /* Initially, the new range has the same set of equivalences of
1477 VAR's range. This will be revised before returning the final
1478 value. Since assertions may be chained via mutually exclusive
1479 predicates, we will need to trim the set of equivalences before
1481 gcc_assert (vr_p->equiv == NULL);
1482 add_equivalence (&vr_p->equiv, var);
1484 /* Extract a new range based on the asserted comparison for VAR and
1485 LIMIT's value range. Notice that if LIMIT has an anti-range, we
1486 will only use it for equality comparisons (EQ_EXPR). For any
1487 other kind of assertion, we cannot derive a range from LIMIT's
1488 anti-range that can be used to describe the new range. For
1489 instance, ASSERT_EXPR <x_2, x_2 <= b_4>. If b_4 is ~[2, 10],
1490 then b_4 takes on the ranges [-INF, 1] and [11, +INF]. There is
1491 no single range for x_2 that could describe LE_EXPR, so we might
1492 as well build the range [b_4, +INF] for it.
1493 One special case we handle is extracting a range from a
1494 range test encoded as (unsigned)var + CST <= limit. */
1495 if (TREE_CODE (cond) == NOP_EXPR
1496 || TREE_CODE (cond) == PLUS_EXPR)
1498 if (TREE_CODE (cond) == PLUS_EXPR)
1500 min = fold_build1 (NEGATE_EXPR, TREE_TYPE (TREE_OPERAND (cond, 1)),
1501 TREE_OPERAND (cond, 1));
1502 max = int_const_binop (PLUS_EXPR, limit, min, 0);
1503 cond = TREE_OPERAND (cond, 0);
1507 min = build_int_cst (TREE_TYPE (var), 0);
1511 /* Make sure to not set TREE_OVERFLOW on the final type
1512 conversion. We are willingly interpreting large positive
1513 unsigned values as negative singed values here. */
1514 min = force_fit_type_double (TREE_TYPE (var), TREE_INT_CST_LOW (min),
1515 TREE_INT_CST_HIGH (min), 0, false);
1516 max = force_fit_type_double (TREE_TYPE (var), TREE_INT_CST_LOW (max),
1517 TREE_INT_CST_HIGH (max), 0, false);
1519 /* We can transform a max, min range to an anti-range or
1520 vice-versa. Use set_and_canonicalize_value_range which does
1522 if (cond_code == LE_EXPR)
1523 set_and_canonicalize_value_range (vr_p, VR_RANGE,
1524 min, max, vr_p->equiv);
1525 else if (cond_code == GT_EXPR)
1526 set_and_canonicalize_value_range (vr_p, VR_ANTI_RANGE,
1527 min, max, vr_p->equiv);
1531 else if (cond_code == EQ_EXPR)
1533 enum value_range_type range_type;
1537 range_type = limit_vr->type;
1538 min = limit_vr->min;
1539 max = limit_vr->max;
1543 range_type = VR_RANGE;
1548 set_value_range (vr_p, range_type, min, max, vr_p->equiv);
1550 /* When asserting the equality VAR == LIMIT and LIMIT is another
1551 SSA name, the new range will also inherit the equivalence set
1553 if (TREE_CODE (limit) == SSA_NAME)
1554 add_equivalence (&vr_p->equiv, limit);
1556 else if (cond_code == NE_EXPR)
1558 /* As described above, when LIMIT's range is an anti-range and
1559 this assertion is an inequality (NE_EXPR), then we cannot
1560 derive anything from the anti-range. For instance, if
1561 LIMIT's range was ~[0, 0], the assertion 'VAR != LIMIT' does
1562 not imply that VAR's range is [0, 0]. So, in the case of
1563 anti-ranges, we just assert the inequality using LIMIT and
1566 If LIMIT_VR is a range, we can only use it to build a new
1567 anti-range if LIMIT_VR is a single-valued range. For
1568 instance, if LIMIT_VR is [0, 1], the predicate
1569 VAR != [0, 1] does not mean that VAR's range is ~[0, 1].
1570 Rather, it means that for value 0 VAR should be ~[0, 0]
1571 and for value 1, VAR should be ~[1, 1]. We cannot
1572 represent these ranges.
1574 The only situation in which we can build a valid
1575 anti-range is when LIMIT_VR is a single-valued range
1576 (i.e., LIMIT_VR->MIN == LIMIT_VR->MAX). In that case,
1577 build the anti-range ~[LIMIT_VR->MIN, LIMIT_VR->MAX]. */
1579 && limit_vr->type == VR_RANGE
1580 && compare_values (limit_vr->min, limit_vr->max) == 0)
1582 min = limit_vr->min;
1583 max = limit_vr->max;
1587 /* In any other case, we cannot use LIMIT's range to build a
1588 valid anti-range. */
1592 /* If MIN and MAX cover the whole range for their type, then
1593 just use the original LIMIT. */
1594 if (INTEGRAL_TYPE_P (type)
1595 && vrp_val_is_min (min)
1596 && vrp_val_is_max (max))
1599 set_value_range (vr_p, VR_ANTI_RANGE, min, max, vr_p->equiv);
1601 else if (cond_code == LE_EXPR || cond_code == LT_EXPR)
1603 min = TYPE_MIN_VALUE (type);
1605 if (limit_vr == NULL || limit_vr->type == VR_ANTI_RANGE)
1609 /* If LIMIT_VR is of the form [N1, N2], we need to build the
1610 range [MIN, N2] for LE_EXPR and [MIN, N2 - 1] for
1612 max = limit_vr->max;
1615 /* If the maximum value forces us to be out of bounds, simply punt.
1616 It would be pointless to try and do anything more since this
1617 all should be optimized away above us. */
1618 if ((cond_code == LT_EXPR
1619 && compare_values (max, min) == 0)
1620 || (CONSTANT_CLASS_P (max) && TREE_OVERFLOW (max)))
1621 set_value_range_to_varying (vr_p);
1624 /* For LT_EXPR, we create the range [MIN, MAX - 1]. */
1625 if (cond_code == LT_EXPR)
1627 tree one = build_int_cst (type, 1);
1628 max = fold_build2 (MINUS_EXPR, type, max, one);
1630 TREE_NO_WARNING (max) = 1;
1633 set_value_range (vr_p, VR_RANGE, min, max, vr_p->equiv);
1636 else if (cond_code == GE_EXPR || cond_code == GT_EXPR)
1638 max = TYPE_MAX_VALUE (type);
1640 if (limit_vr == NULL || limit_vr->type == VR_ANTI_RANGE)
1644 /* If LIMIT_VR is of the form [N1, N2], we need to build the
1645 range [N1, MAX] for GE_EXPR and [N1 + 1, MAX] for
1647 min = limit_vr->min;
1650 /* If the minimum value forces us to be out of bounds, simply punt.
1651 It would be pointless to try and do anything more since this
1652 all should be optimized away above us. */
1653 if ((cond_code == GT_EXPR
1654 && compare_values (min, max) == 0)
1655 || (CONSTANT_CLASS_P (min) && TREE_OVERFLOW (min)))
1656 set_value_range_to_varying (vr_p);
1659 /* For GT_EXPR, we create the range [MIN + 1, MAX]. */
1660 if (cond_code == GT_EXPR)
1662 tree one = build_int_cst (type, 1);
1663 min = fold_build2 (PLUS_EXPR, type, min, one);
1665 TREE_NO_WARNING (min) = 1;
1668 set_value_range (vr_p, VR_RANGE, min, max, vr_p->equiv);
1674 /* If VAR already had a known range, it may happen that the new
1675 range we have computed and VAR's range are not compatible. For
1679 p_6 = ASSERT_EXPR <p_5, p_5 == NULL>;
1681 p_8 = ASSERT_EXPR <p_6, p_6 != NULL>;
1683 While the above comes from a faulty program, it will cause an ICE
1684 later because p_8 and p_6 will have incompatible ranges and at
1685 the same time will be considered equivalent. A similar situation
1689 i_6 = ASSERT_EXPR <i_5, i_5 > 10>;
1691 i_7 = ASSERT_EXPR <i_6, i_6 < 5>;
1693 Again i_6 and i_7 will have incompatible ranges. It would be
1694 pointless to try and do anything with i_7's range because
1695 anything dominated by 'if (i_5 < 5)' will be optimized away.
1696 Note, due to the wa in which simulation proceeds, the statement
1697 i_7 = ASSERT_EXPR <...> we would never be visited because the
1698 conditional 'if (i_5 < 5)' always evaluates to false. However,
1699 this extra check does not hurt and may protect against future
1700 changes to VRP that may get into a situation similar to the
1701 NULL pointer dereference example.
1703 Note that these compatibility tests are only needed when dealing
1704 with ranges or a mix of range and anti-range. If VAR_VR and VR_P
1705 are both anti-ranges, they will always be compatible, because two
1706 anti-ranges will always have a non-empty intersection. */
1708 var_vr = get_value_range (var);
1710 /* We may need to make adjustments when VR_P and VAR_VR are numeric
1711 ranges or anti-ranges. */
1712 if (vr_p->type == VR_VARYING
1713 || vr_p->type == VR_UNDEFINED
1714 || var_vr->type == VR_VARYING
1715 || var_vr->type == VR_UNDEFINED
1716 || symbolic_range_p (vr_p)
1717 || symbolic_range_p (var_vr))
1720 if (var_vr->type == VR_RANGE && vr_p->type == VR_RANGE)
1722 /* If the two ranges have a non-empty intersection, we can
1723 refine the resulting range. Since the assert expression
1724 creates an equivalency and at the same time it asserts a
1725 predicate, we can take the intersection of the two ranges to
1726 get better precision. */
1727 if (value_ranges_intersect_p (var_vr, vr_p))
1729 /* Use the larger of the two minimums. */
1730 if (compare_values (vr_p->min, var_vr->min) == -1)
1735 /* Use the smaller of the two maximums. */
1736 if (compare_values (vr_p->max, var_vr->max) == 1)
1741 set_value_range (vr_p, vr_p->type, min, max, vr_p->equiv);
1745 /* The two ranges do not intersect, set the new range to
1746 VARYING, because we will not be able to do anything
1747 meaningful with it. */
1748 set_value_range_to_varying (vr_p);
1751 else if ((var_vr->type == VR_RANGE && vr_p->type == VR_ANTI_RANGE)
1752 || (var_vr->type == VR_ANTI_RANGE && vr_p->type == VR_RANGE))
1754 /* A range and an anti-range will cancel each other only if
1755 their ends are the same. For instance, in the example above,
1756 p_8's range ~[0, 0] and p_6's range [0, 0] are incompatible,
1757 so VR_P should be set to VR_VARYING. */
1758 if (compare_values (var_vr->min, vr_p->min) == 0
1759 && compare_values (var_vr->max, vr_p->max) == 0)
1760 set_value_range_to_varying (vr_p);
1763 tree min, max, anti_min, anti_max, real_min, real_max;
1766 /* We want to compute the logical AND of the two ranges;
1767 there are three cases to consider.
1770 1. The VR_ANTI_RANGE range is completely within the
1771 VR_RANGE and the endpoints of the ranges are
1772 different. In that case the resulting range
1773 should be whichever range is more precise.
1774 Typically that will be the VR_RANGE.
1776 2. The VR_ANTI_RANGE is completely disjoint from
1777 the VR_RANGE. In this case the resulting range
1778 should be the VR_RANGE.
1780 3. There is some overlap between the VR_ANTI_RANGE
1783 3a. If the high limit of the VR_ANTI_RANGE resides
1784 within the VR_RANGE, then the result is a new
1785 VR_RANGE starting at the high limit of the
1786 VR_ANTI_RANGE + 1 and extending to the
1787 high limit of the original VR_RANGE.
1789 3b. If the low limit of the VR_ANTI_RANGE resides
1790 within the VR_RANGE, then the result is a new
1791 VR_RANGE starting at the low limit of the original
1792 VR_RANGE and extending to the low limit of the
1793 VR_ANTI_RANGE - 1. */
1794 if (vr_p->type == VR_ANTI_RANGE)
1796 anti_min = vr_p->min;
1797 anti_max = vr_p->max;
1798 real_min = var_vr->min;
1799 real_max = var_vr->max;
1803 anti_min = var_vr->min;
1804 anti_max = var_vr->max;
1805 real_min = vr_p->min;
1806 real_max = vr_p->max;
1810 /* Case 1, VR_ANTI_RANGE completely within VR_RANGE,
1811 not including any endpoints. */
1812 if (compare_values (anti_max, real_max) == -1
1813 && compare_values (anti_min, real_min) == 1)
1815 /* If the range is covering the whole valid range of
1816 the type keep the anti-range. */
1817 if (!vrp_val_is_min (real_min)
1818 || !vrp_val_is_max (real_max))
1819 set_value_range (vr_p, VR_RANGE, real_min,
1820 real_max, vr_p->equiv);
1822 /* Case 2, VR_ANTI_RANGE completely disjoint from
1824 else if (compare_values (anti_min, real_max) == 1
1825 || compare_values (anti_max, real_min) == -1)
1827 set_value_range (vr_p, VR_RANGE, real_min,
1828 real_max, vr_p->equiv);
1830 /* Case 3a, the anti-range extends into the low
1831 part of the real range. Thus creating a new
1832 low for the real range. */
1833 else if (((cmp = compare_values (anti_max, real_min)) == 1
1835 && compare_values (anti_max, real_max) == -1)
1837 gcc_assert (!is_positive_overflow_infinity (anti_max));
1838 if (needs_overflow_infinity (TREE_TYPE (anti_max))
1839 && vrp_val_is_max (anti_max))
1841 if (!supports_overflow_infinity (TREE_TYPE (var_vr->min)))
1843 set_value_range_to_varying (vr_p);
1846 min = positive_overflow_infinity (TREE_TYPE (var_vr->min));
1848 else if (!POINTER_TYPE_P (TREE_TYPE (var_vr->min)))
1849 min = fold_build2 (PLUS_EXPR, TREE_TYPE (var_vr->min),
1851 build_int_cst (TREE_TYPE (var_vr->min), 1));
1853 min = fold_build2 (POINTER_PLUS_EXPR, TREE_TYPE (var_vr->min),
1854 anti_max, size_int (1));
1856 set_value_range (vr_p, VR_RANGE, min, max, vr_p->equiv);
1858 /* Case 3b, the anti-range extends into the high
1859 part of the real range. Thus creating a new
1860 higher for the real range. */
1861 else if (compare_values (anti_min, real_min) == 1
1862 && ((cmp = compare_values (anti_min, real_max)) == -1
1865 gcc_assert (!is_negative_overflow_infinity (anti_min));
1866 if (needs_overflow_infinity (TREE_TYPE (anti_min))
1867 && vrp_val_is_min (anti_min))
1869 if (!supports_overflow_infinity (TREE_TYPE (var_vr->min)))
1871 set_value_range_to_varying (vr_p);
1874 max = negative_overflow_infinity (TREE_TYPE (var_vr->min));
1876 else if (!POINTER_TYPE_P (TREE_TYPE (var_vr->min)))
1877 max = fold_build2 (MINUS_EXPR, TREE_TYPE (var_vr->min),
1879 build_int_cst (TREE_TYPE (var_vr->min), 1));
1881 max = fold_build2 (POINTER_PLUS_EXPR, TREE_TYPE (var_vr->min),
1885 set_value_range (vr_p, VR_RANGE, min, max, vr_p->equiv);
1892 /* Extract range information from SSA name VAR and store it in VR. If
1893 VAR has an interesting range, use it. Otherwise, create the
1894 range [VAR, VAR] and return it. This is useful in situations where
1895 we may have conditionals testing values of VARYING names. For
1902 Even if y_5 is deemed VARYING, we can determine that x_3 > y_5 is
1906 extract_range_from_ssa_name (value_range_t *vr, tree var)
1908 value_range_t *var_vr = get_value_range (var);
1910 if (var_vr->type != VR_UNDEFINED && var_vr->type != VR_VARYING)
1911 copy_value_range (vr, var_vr);
1913 set_value_range (vr, VR_RANGE, var, var, NULL);
1915 add_equivalence (&vr->equiv, var);
1919 /* Wrapper around int_const_binop. If the operation overflows and we
1920 are not using wrapping arithmetic, then adjust the result to be
1921 -INF or +INF depending on CODE, VAL1 and VAL2. This can return
1922 NULL_TREE if we need to use an overflow infinity representation but
1923 the type does not support it. */
1926 vrp_int_const_binop (enum tree_code code, tree val1, tree val2)
1930 res = int_const_binop (code, val1, val2, 0);
1932 /* If we are using unsigned arithmetic, operate symbolically
1933 on -INF and +INF as int_const_binop only handles signed overflow. */
1934 if (TYPE_UNSIGNED (TREE_TYPE (val1)))
1936 int checkz = compare_values (res, val1);
1937 bool overflow = false;
1939 /* Ensure that res = val1 [+*] val2 >= val1
1940 or that res = val1 - val2 <= val1. */
1941 if ((code == PLUS_EXPR
1942 && !(checkz == 1 || checkz == 0))
1943 || (code == MINUS_EXPR
1944 && !(checkz == 0 || checkz == -1)))
1948 /* Checking for multiplication overflow is done by dividing the
1949 output of the multiplication by the first input of the
1950 multiplication. If the result of that division operation is
1951 not equal to the second input of the multiplication, then the
1952 multiplication overflowed. */
1953 else if (code == MULT_EXPR && !integer_zerop (val1))
1955 tree tmp = int_const_binop (TRUNC_DIV_EXPR,
1958 int check = compare_values (tmp, val2);
1966 res = copy_node (res);
1967 TREE_OVERFLOW (res) = 1;
1971 else if (TYPE_OVERFLOW_WRAPS (TREE_TYPE (val1)))
1972 /* If the singed operation wraps then int_const_binop has done
1973 everything we want. */
1975 else if ((TREE_OVERFLOW (res)
1976 && !TREE_OVERFLOW (val1)
1977 && !TREE_OVERFLOW (val2))
1978 || is_overflow_infinity (val1)
1979 || is_overflow_infinity (val2))
1981 /* If the operation overflowed but neither VAL1 nor VAL2 are
1982 overflown, return -INF or +INF depending on the operation
1983 and the combination of signs of the operands. */
1984 int sgn1 = tree_int_cst_sgn (val1);
1985 int sgn2 = tree_int_cst_sgn (val2);
1987 if (needs_overflow_infinity (TREE_TYPE (res))
1988 && !supports_overflow_infinity (TREE_TYPE (res)))
1991 /* We have to punt on adding infinities of different signs,
1992 since we can't tell what the sign of the result should be.
1993 Likewise for subtracting infinities of the same sign. */
1994 if (((code == PLUS_EXPR && sgn1 != sgn2)
1995 || (code == MINUS_EXPR && sgn1 == sgn2))
1996 && is_overflow_infinity (val1)
1997 && is_overflow_infinity (val2))
2000 /* Don't try to handle division or shifting of infinities. */
2001 if ((code == TRUNC_DIV_EXPR
2002 || code == FLOOR_DIV_EXPR
2003 || code == CEIL_DIV_EXPR
2004 || code == EXACT_DIV_EXPR
2005 || code == ROUND_DIV_EXPR
2006 || code == RSHIFT_EXPR)
2007 && (is_overflow_infinity (val1)
2008 || is_overflow_infinity (val2)))
2011 /* Notice that we only need to handle the restricted set of
2012 operations handled by extract_range_from_binary_expr.
2013 Among them, only multiplication, addition and subtraction
2014 can yield overflow without overflown operands because we
2015 are working with integral types only... except in the
2016 case VAL1 = -INF and VAL2 = -1 which overflows to +INF
2017 for division too. */
2019 /* For multiplication, the sign of the overflow is given
2020 by the comparison of the signs of the operands. */
2021 if ((code == MULT_EXPR && sgn1 == sgn2)
2022 /* For addition, the operands must be of the same sign
2023 to yield an overflow. Its sign is therefore that
2024 of one of the operands, for example the first. For
2025 infinite operands X + -INF is negative, not positive. */
2026 || (code == PLUS_EXPR
2028 ? !is_negative_overflow_infinity (val2)
2029 : is_positive_overflow_infinity (val2)))
2030 /* For subtraction, non-infinite operands must be of
2031 different signs to yield an overflow. Its sign is
2032 therefore that of the first operand or the opposite of
2033 that of the second operand. A first operand of 0 counts
2034 as positive here, for the corner case 0 - (-INF), which
2035 overflows, but must yield +INF. For infinite operands 0
2036 - INF is negative, not positive. */
2037 || (code == MINUS_EXPR
2039 ? !is_positive_overflow_infinity (val2)
2040 : is_negative_overflow_infinity (val2)))
2041 /* We only get in here with positive shift count, so the
2042 overflow direction is the same as the sign of val1.
2043 Actually rshift does not overflow at all, but we only
2044 handle the case of shifting overflowed -INF and +INF. */
2045 || (code == RSHIFT_EXPR
2047 /* For division, the only case is -INF / -1 = +INF. */
2048 || code == TRUNC_DIV_EXPR
2049 || code == FLOOR_DIV_EXPR
2050 || code == CEIL_DIV_EXPR
2051 || code == EXACT_DIV_EXPR
2052 || code == ROUND_DIV_EXPR)
2053 return (needs_overflow_infinity (TREE_TYPE (res))
2054 ? positive_overflow_infinity (TREE_TYPE (res))
2055 : TYPE_MAX_VALUE (TREE_TYPE (res)));
2057 return (needs_overflow_infinity (TREE_TYPE (res))
2058 ? negative_overflow_infinity (TREE_TYPE (res))
2059 : TYPE_MIN_VALUE (TREE_TYPE (res)));
2066 /* Extract range information from a binary expression EXPR based on
2067 the ranges of each of its operands and the expression code. */
2070 extract_range_from_binary_expr (value_range_t *vr,
2071 enum tree_code code,
2072 tree expr_type, tree op0, tree op1)
2074 enum value_range_type type;
2077 value_range_t vr0 = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
2078 value_range_t vr1 = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
2080 /* Not all binary expressions can be applied to ranges in a
2081 meaningful way. Handle only arithmetic operations. */
2082 if (code != PLUS_EXPR
2083 && code != MINUS_EXPR
2084 && code != POINTER_PLUS_EXPR
2085 && code != MULT_EXPR
2086 && code != TRUNC_DIV_EXPR
2087 && code != FLOOR_DIV_EXPR
2088 && code != CEIL_DIV_EXPR
2089 && code != EXACT_DIV_EXPR
2090 && code != ROUND_DIV_EXPR
2091 && code != TRUNC_MOD_EXPR
2092 && code != RSHIFT_EXPR
2095 && code != BIT_AND_EXPR
2096 && code != BIT_IOR_EXPR
2097 && code != TRUTH_AND_EXPR
2098 && code != TRUTH_OR_EXPR)
2100 /* We can still do constant propagation here. */
2101 tree const_op0 = op_with_constant_singleton_value_range (op0);
2102 tree const_op1 = op_with_constant_singleton_value_range (op1);
2103 if (const_op0 || const_op1)
2105 tree tem = fold_binary (code, expr_type,
2106 const_op0 ? const_op0 : op0,
2107 const_op1 ? const_op1 : op1);
2109 && is_gimple_min_invariant (tem)
2110 && !is_overflow_infinity (tem))
2112 set_value_range (vr, VR_RANGE, tem, tem, NULL);
2116 set_value_range_to_varying (vr);
2120 /* Get value ranges for each operand. For constant operands, create
2121 a new value range with the operand to simplify processing. */
2122 if (TREE_CODE (op0) == SSA_NAME)
2123 vr0 = *(get_value_range (op0));
2124 else if (is_gimple_min_invariant (op0))
2125 set_value_range_to_value (&vr0, op0, NULL);
2127 set_value_range_to_varying (&vr0);
2129 if (TREE_CODE (op1) == SSA_NAME)
2130 vr1 = *(get_value_range (op1));
2131 else if (is_gimple_min_invariant (op1))
2132 set_value_range_to_value (&vr1, op1, NULL);
2134 set_value_range_to_varying (&vr1);
2136 /* If either range is UNDEFINED, so is the result. */
2137 if (vr0.type == VR_UNDEFINED || vr1.type == VR_UNDEFINED)
2139 set_value_range_to_undefined (vr);
2143 /* The type of the resulting value range defaults to VR0.TYPE. */
2146 /* Refuse to operate on VARYING ranges, ranges of different kinds
2147 and symbolic ranges. As an exception, we allow BIT_AND_EXPR
2148 because we may be able to derive a useful range even if one of
2149 the operands is VR_VARYING or symbolic range. Similarly for
2150 divisions. TODO, we may be able to derive anti-ranges in
2152 if (code != BIT_AND_EXPR
2153 && code != TRUTH_AND_EXPR
2154 && code != TRUTH_OR_EXPR
2155 && code != TRUNC_DIV_EXPR
2156 && code != FLOOR_DIV_EXPR
2157 && code != CEIL_DIV_EXPR
2158 && code != EXACT_DIV_EXPR
2159 && code != ROUND_DIV_EXPR
2160 && code != TRUNC_MOD_EXPR
2161 && (vr0.type == VR_VARYING
2162 || vr1.type == VR_VARYING
2163 || vr0.type != vr1.type
2164 || symbolic_range_p (&vr0)
2165 || symbolic_range_p (&vr1)))
2167 set_value_range_to_varying (vr);
2171 /* Now evaluate the expression to determine the new range. */
2172 if (POINTER_TYPE_P (expr_type)
2173 || POINTER_TYPE_P (TREE_TYPE (op0))
2174 || POINTER_TYPE_P (TREE_TYPE (op1)))
2176 if (code == MIN_EXPR || code == MAX_EXPR)
2178 /* For MIN/MAX expressions with pointers, we only care about
2179 nullness, if both are non null, then the result is nonnull.
2180 If both are null, then the result is null. Otherwise they
2182 if (range_is_nonnull (&vr0) && range_is_nonnull (&vr1))
2183 set_value_range_to_nonnull (vr, expr_type);
2184 else if (range_is_null (&vr0) && range_is_null (&vr1))
2185 set_value_range_to_null (vr, expr_type);
2187 set_value_range_to_varying (vr);
2191 gcc_assert (code == POINTER_PLUS_EXPR);
2192 /* For pointer types, we are really only interested in asserting
2193 whether the expression evaluates to non-NULL. */
2194 if (range_is_nonnull (&vr0) || range_is_nonnull (&vr1))
2195 set_value_range_to_nonnull (vr, expr_type);
2196 else if (range_is_null (&vr0) && range_is_null (&vr1))
2197 set_value_range_to_null (vr, expr_type);
2199 set_value_range_to_varying (vr);
2204 /* For integer ranges, apply the operation to each end of the
2205 range and see what we end up with. */
2206 if (code == TRUTH_AND_EXPR
2207 || code == TRUTH_OR_EXPR)
2209 /* If one of the operands is zero, we know that the whole
2210 expression evaluates zero. */
2211 if (code == TRUTH_AND_EXPR
2212 && ((vr0.type == VR_RANGE
2213 && integer_zerop (vr0.min)
2214 && integer_zerop (vr0.max))
2215 || (vr1.type == VR_RANGE
2216 && integer_zerop (vr1.min)
2217 && integer_zerop (vr1.max))))
2220 min = max = build_int_cst (expr_type, 0);
2222 /* If one of the operands is one, we know that the whole
2223 expression evaluates one. */
2224 else if (code == TRUTH_OR_EXPR
2225 && ((vr0.type == VR_RANGE
2226 && integer_onep (vr0.min)
2227 && integer_onep (vr0.max))
2228 || (vr1.type == VR_RANGE
2229 && integer_onep (vr1.min)
2230 && integer_onep (vr1.max))))
2233 min = max = build_int_cst (expr_type, 1);
2235 else if (vr0.type != VR_VARYING
2236 && vr1.type != VR_VARYING
2237 && vr0.type == vr1.type
2238 && !symbolic_range_p (&vr0)
2239 && !overflow_infinity_range_p (&vr0)
2240 && !symbolic_range_p (&vr1)
2241 && !overflow_infinity_range_p (&vr1))
2243 /* Boolean expressions cannot be folded with int_const_binop. */
2244 min = fold_binary (code, expr_type, vr0.min, vr1.min);
2245 max = fold_binary (code, expr_type, vr0.max, vr1.max);
2249 /* The result of a TRUTH_*_EXPR is always true or false. */
2250 set_value_range_to_truthvalue (vr, expr_type);
2254 else if (code == PLUS_EXPR
2256 || code == MAX_EXPR)
2258 /* If we have a PLUS_EXPR with two VR_ANTI_RANGEs, drop to
2259 VR_VARYING. It would take more effort to compute a precise
2260 range for such a case. For example, if we have op0 == 1 and
2261 op1 == -1 with their ranges both being ~[0,0], we would have
2262 op0 + op1 == 0, so we cannot claim that the sum is in ~[0,0].
2263 Note that we are guaranteed to have vr0.type == vr1.type at
2265 if (code == PLUS_EXPR && vr0.type == VR_ANTI_RANGE)
2267 set_value_range_to_varying (vr);
2271 /* For operations that make the resulting range directly
2272 proportional to the original ranges, apply the operation to
2273 the same end of each range. */
2274 min = vrp_int_const_binop (code, vr0.min, vr1.min);
2275 max = vrp_int_const_binop (code, vr0.max, vr1.max);
2277 /* If both additions overflowed the range kind is still correct.
2278 This happens regularly with subtracting something in unsigned
2280 ??? See PR30318 for all the cases we do not handle. */
2281 if (code == PLUS_EXPR
2282 && (TREE_OVERFLOW (min) && !is_overflow_infinity (min))
2283 && (TREE_OVERFLOW (max) && !is_overflow_infinity (max)))
2285 min = build_int_cst_wide (TREE_TYPE (min),
2286 TREE_INT_CST_LOW (min),
2287 TREE_INT_CST_HIGH (min));
2288 max = build_int_cst_wide (TREE_TYPE (max),
2289 TREE_INT_CST_LOW (max),
2290 TREE_INT_CST_HIGH (max));
2293 else if (code == MULT_EXPR
2294 || code == TRUNC_DIV_EXPR
2295 || code == FLOOR_DIV_EXPR
2296 || code == CEIL_DIV_EXPR
2297 || code == EXACT_DIV_EXPR
2298 || code == ROUND_DIV_EXPR
2299 || code == RSHIFT_EXPR)
2305 /* If we have an unsigned MULT_EXPR with two VR_ANTI_RANGEs,
2306 drop to VR_VARYING. It would take more effort to compute a
2307 precise range for such a case. For example, if we have
2308 op0 == 65536 and op1 == 65536 with their ranges both being
2309 ~[0,0] on a 32-bit machine, we would have op0 * op1 == 0, so
2310 we cannot claim that the product is in ~[0,0]. Note that we
2311 are guaranteed to have vr0.type == vr1.type at this
2313 if (code == MULT_EXPR
2314 && vr0.type == VR_ANTI_RANGE
2315 && !TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (op0)))
2317 set_value_range_to_varying (vr);
2321 /* If we have a RSHIFT_EXPR with any shift values outside [0..prec-1],
2322 then drop to VR_VARYING. Outside of this range we get undefined
2323 behavior from the shift operation. We cannot even trust
2324 SHIFT_COUNT_TRUNCATED at this stage, because that applies to rtl
2325 shifts, and the operation at the tree level may be widened. */
2326 if (code == RSHIFT_EXPR)
2328 if (vr1.type == VR_ANTI_RANGE
2329 || !vrp_expr_computes_nonnegative (op1, &sop)
2331 (build_int_cst (TREE_TYPE (vr1.max),
2332 TYPE_PRECISION (expr_type) - 1),
2335 set_value_range_to_varying (vr);
2340 else if ((code == TRUNC_DIV_EXPR
2341 || code == FLOOR_DIV_EXPR
2342 || code == CEIL_DIV_EXPR
2343 || code == EXACT_DIV_EXPR
2344 || code == ROUND_DIV_EXPR)
2345 && (vr0.type != VR_RANGE || symbolic_range_p (&vr0)))
2347 /* For division, if op1 has VR_RANGE but op0 does not, something
2348 can be deduced just from that range. Say [min, max] / [4, max]
2349 gives [min / 4, max / 4] range. */
2350 if (vr1.type == VR_RANGE
2351 && !symbolic_range_p (&vr1)
2352 && !range_includes_zero_p (&vr1))
2354 vr0.type = type = VR_RANGE;
2355 vr0.min = vrp_val_min (TREE_TYPE (op0));
2356 vr0.max = vrp_val_max (TREE_TYPE (op1));
2360 set_value_range_to_varying (vr);
2365 /* For divisions, if op0 is VR_RANGE, we can deduce a range
2366 even if op1 is VR_VARYING, VR_ANTI_RANGE, symbolic or can
2368 if ((code == TRUNC_DIV_EXPR
2369 || code == FLOOR_DIV_EXPR
2370 || code == CEIL_DIV_EXPR
2371 || code == EXACT_DIV_EXPR
2372 || code == ROUND_DIV_EXPR)
2373 && vr0.type == VR_RANGE
2374 && (vr1.type != VR_RANGE
2375 || symbolic_range_p (&vr1)
2376 || range_includes_zero_p (&vr1)))
2378 tree zero = build_int_cst (TREE_TYPE (vr0.min), 0);
2384 if (vrp_expr_computes_nonnegative (op1, &sop) && !sop)
2386 /* For unsigned division or when divisor is known
2387 to be non-negative, the range has to cover
2388 all numbers from 0 to max for positive max
2389 and all numbers from min to 0 for negative min. */
2390 cmp = compare_values (vr0.max, zero);
2393 else if (cmp == 0 || cmp == 1)
2397 cmp = compare_values (vr0.min, zero);
2400 else if (cmp == 0 || cmp == -1)
2407 /* Otherwise the range is -max .. max or min .. -min
2408 depending on which bound is bigger in absolute value,
2409 as the division can change the sign. */
2410 abs_extent_range (vr, vr0.min, vr0.max);
2413 if (type == VR_VARYING)
2415 set_value_range_to_varying (vr);
2420 /* Multiplications and divisions are a bit tricky to handle,
2421 depending on the mix of signs we have in the two ranges, we
2422 need to operate on different values to get the minimum and
2423 maximum values for the new range. One approach is to figure
2424 out all the variations of range combinations and do the
2427 However, this involves several calls to compare_values and it
2428 is pretty convoluted. It's simpler to do the 4 operations
2429 (MIN0 OP MIN1, MIN0 OP MAX1, MAX0 OP MIN1 and MAX0 OP MAX0 OP
2430 MAX1) and then figure the smallest and largest values to form
2434 gcc_assert ((vr0.type == VR_RANGE
2435 || (code == MULT_EXPR && vr0.type == VR_ANTI_RANGE))
2436 && vr0.type == vr1.type);
2438 /* Compute the 4 cross operations. */
2440 val[0] = vrp_int_const_binop (code, vr0.min, vr1.min);
2441 if (val[0] == NULL_TREE)
2444 if (vr1.max == vr1.min)
2448 val[1] = vrp_int_const_binop (code, vr0.min, vr1.max);
2449 if (val[1] == NULL_TREE)
2453 if (vr0.max == vr0.min)
2457 val[2] = vrp_int_const_binop (code, vr0.max, vr1.min);
2458 if (val[2] == NULL_TREE)
2462 if (vr0.min == vr0.max || vr1.min == vr1.max)
2466 val[3] = vrp_int_const_binop (code, vr0.max, vr1.max);
2467 if (val[3] == NULL_TREE)
2473 set_value_range_to_varying (vr);
2477 /* Set MIN to the minimum of VAL[i] and MAX to the maximum
2481 for (i = 1; i < 4; i++)
2483 if (!is_gimple_min_invariant (min)
2484 || (TREE_OVERFLOW (min) && !is_overflow_infinity (min))
2485 || !is_gimple_min_invariant (max)
2486 || (TREE_OVERFLOW (max) && !is_overflow_infinity (max)))
2491 if (!is_gimple_min_invariant (val[i])
2492 || (TREE_OVERFLOW (val[i])
2493 && !is_overflow_infinity (val[i])))
2495 /* If we found an overflowed value, set MIN and MAX
2496 to it so that we set the resulting range to
2502 if (compare_values (val[i], min) == -1)
2505 if (compare_values (val[i], max) == 1)
2511 else if (code == TRUNC_MOD_EXPR)
2514 if (vr1.type != VR_RANGE
2515 || symbolic_range_p (&vr1)
2516 || range_includes_zero_p (&vr1)
2517 || vrp_val_is_min (vr1.min))
2519 set_value_range_to_varying (vr);
2523 /* Compute MAX <|vr1.min|, |vr1.max|> - 1. */
2524 max = fold_unary_to_constant (ABS_EXPR, TREE_TYPE (vr1.min), vr1.min);
2525 if (tree_int_cst_lt (max, vr1.max))
2527 max = int_const_binop (MINUS_EXPR, max, integer_one_node, 0);
2528 /* If the dividend is non-negative the modulus will be
2529 non-negative as well. */
2530 if (TYPE_UNSIGNED (TREE_TYPE (max))
2531 || (vrp_expr_computes_nonnegative (op0, &sop) && !sop))
2532 min = build_int_cst (TREE_TYPE (max), 0);
2534 min = fold_unary_to_constant (NEGATE_EXPR, TREE_TYPE (max), max);
2536 else if (code == MINUS_EXPR)
2538 /* If we have a MINUS_EXPR with two VR_ANTI_RANGEs, drop to
2539 VR_VARYING. It would take more effort to compute a precise
2540 range for such a case. For example, if we have op0 == 1 and
2541 op1 == 1 with their ranges both being ~[0,0], we would have
2542 op0 - op1 == 0, so we cannot claim that the difference is in
2543 ~[0,0]. Note that we are guaranteed to have
2544 vr0.type == vr1.type at this point. */
2545 if (vr0.type == VR_ANTI_RANGE)
2547 set_value_range_to_varying (vr);
2551 /* For MINUS_EXPR, apply the operation to the opposite ends of
2553 min = vrp_int_const_binop (code, vr0.min, vr1.max);
2554 max = vrp_int_const_binop (code, vr0.max, vr1.min);
2556 else if (code == BIT_AND_EXPR)
2558 bool vr0_int_cst_singleton_p, vr1_int_cst_singleton_p;
2560 vr0_int_cst_singleton_p = range_int_cst_singleton_p (&vr0);
2561 vr1_int_cst_singleton_p = range_int_cst_singleton_p (&vr1);
2563 if (vr0_int_cst_singleton_p && vr1_int_cst_singleton_p)
2564 min = max = int_const_binop (code, vr0.max, vr1.max, 0);
2565 else if (vr0_int_cst_singleton_p
2566 && tree_int_cst_sgn (vr0.max) >= 0)
2568 min = build_int_cst (expr_type, 0);
2571 else if (vr1_int_cst_singleton_p
2572 && tree_int_cst_sgn (vr1.max) >= 0)
2575 min = build_int_cst (expr_type, 0);
2580 set_value_range_to_varying (vr);
2584 else if (code == BIT_IOR_EXPR)
2586 if (range_int_cst_p (&vr0)
2587 && range_int_cst_p (&vr1)
2588 && tree_int_cst_sgn (vr0.min) >= 0
2589 && tree_int_cst_sgn (vr1.min) >= 0)
2591 double_int vr0_max = tree_to_double_int (vr0.max);
2592 double_int vr1_max = tree_to_double_int (vr1.max);
2595 /* Set all bits to the right of the most significant one to 1.
2596 For example, [0, 4] | [4, 4] = [4, 7]. */
2597 ior_max.low = vr0_max.low | vr1_max.low;
2598 ior_max.high = vr0_max.high | vr1_max.high;
2599 if (ior_max.high != 0)
2601 ior_max.low = ~(unsigned HOST_WIDE_INT)0u;
2602 ior_max.high |= ((HOST_WIDE_INT) 1
2603 << floor_log2 (ior_max.high)) - 1;
2605 else if (ior_max.low != 0)
2606 ior_max.low |= ((unsigned HOST_WIDE_INT) 1u
2607 << floor_log2 (ior_max.low)) - 1;
2609 /* Both of these endpoints are conservative. */
2610 min = vrp_int_const_binop (MAX_EXPR, vr0.min, vr1.min);
2611 max = double_int_to_tree (expr_type, ior_max);
2615 set_value_range_to_varying (vr);
2622 /* If either MIN or MAX overflowed, then set the resulting range to
2623 VARYING. But we do accept an overflow infinity
2625 if (min == NULL_TREE
2626 || !is_gimple_min_invariant (min)
2627 || (TREE_OVERFLOW (min) && !is_overflow_infinity (min))
2629 || !is_gimple_min_invariant (max)
2630 || (TREE_OVERFLOW (max) && !is_overflow_infinity (max)))
2632 set_value_range_to_varying (vr);
2638 2) [-INF, +-INF(OVF)]
2639 3) [+-INF(OVF), +INF]
2640 4) [+-INF(OVF), +-INF(OVF)]
2641 We learn nothing when we have INF and INF(OVF) on both sides.
2642 Note that we do accept [-INF, -INF] and [+INF, +INF] without
2644 if ((vrp_val_is_min (min) || is_overflow_infinity (min))
2645 && (vrp_val_is_max (max) || is_overflow_infinity (max)))
2647 set_value_range_to_varying (vr);
2651 cmp = compare_values (min, max);
2652 if (cmp == -2 || cmp == 1)
2654 /* If the new range has its limits swapped around (MIN > MAX),
2655 then the operation caused one of them to wrap around, mark
2656 the new range VARYING. */
2657 set_value_range_to_varying (vr);
2660 set_value_range (vr, type, min, max, NULL);
2664 /* Extract range information from a unary expression EXPR based on
2665 the range of its operand and the expression code. */
2668 extract_range_from_unary_expr (value_range_t *vr, enum tree_code code,
2669 tree type, tree op0)
2673 value_range_t vr0 = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
2675 /* Refuse to operate on certain unary expressions for which we
2676 cannot easily determine a resulting range. */
2677 if (code == FIX_TRUNC_EXPR
2678 || code == FLOAT_EXPR
2679 || code == BIT_NOT_EXPR
2680 || code == CONJ_EXPR)
2682 /* We can still do constant propagation here. */
2683 if ((op0 = op_with_constant_singleton_value_range (op0)) != NULL_TREE)
2685 tree tem = fold_unary (code, type, op0);
2687 && is_gimple_min_invariant (tem)
2688 && !is_overflow_infinity (tem))
2690 set_value_range (vr, VR_RANGE, tem, tem, NULL);
2694 set_value_range_to_varying (vr);
2698 /* Get value ranges for the operand. For constant operands, create
2699 a new value range with the operand to simplify processing. */
2700 if (TREE_CODE (op0) == SSA_NAME)
2701 vr0 = *(get_value_range (op0));
2702 else if (is_gimple_min_invariant (op0))
2703 set_value_range_to_value (&vr0, op0, NULL);
2705 set_value_range_to_varying (&vr0);
2707 /* If VR0 is UNDEFINED, so is the result. */
2708 if (vr0.type == VR_UNDEFINED)
2710 set_value_range_to_undefined (vr);
2714 /* Refuse to operate on symbolic ranges, or if neither operand is
2715 a pointer or integral type. */
2716 if ((!INTEGRAL_TYPE_P (TREE_TYPE (op0))
2717 && !POINTER_TYPE_P (TREE_TYPE (op0)))
2718 || (vr0.type != VR_VARYING
2719 && symbolic_range_p (&vr0)))
2721 set_value_range_to_varying (vr);
2725 /* If the expression involves pointers, we are only interested in
2726 determining if it evaluates to NULL [0, 0] or non-NULL (~[0, 0]). */
2727 if (POINTER_TYPE_P (type) || POINTER_TYPE_P (TREE_TYPE (op0)))
2732 if (range_is_nonnull (&vr0)
2733 || (tree_unary_nonzero_warnv_p (code, type, op0, &sop)
2735 set_value_range_to_nonnull (vr, type);
2736 else if (range_is_null (&vr0))
2737 set_value_range_to_null (vr, type);
2739 set_value_range_to_varying (vr);
2744 /* Handle unary expressions on integer ranges. */
2745 if (CONVERT_EXPR_CODE_P (code)
2746 && INTEGRAL_TYPE_P (type)
2747 && INTEGRAL_TYPE_P (TREE_TYPE (op0)))
2749 tree inner_type = TREE_TYPE (op0);
2750 tree outer_type = type;
2752 /* If VR0 is varying and we increase the type precision, assume
2753 a full range for the following transformation. */
2754 if (vr0.type == VR_VARYING
2755 && TYPE_PRECISION (inner_type) < TYPE_PRECISION (outer_type))
2757 vr0.type = VR_RANGE;
2758 vr0.min = TYPE_MIN_VALUE (inner_type);
2759 vr0.max = TYPE_MAX_VALUE (inner_type);
2762 /* If VR0 is a constant range or anti-range and the conversion is
2763 not truncating we can convert the min and max values and
2764 canonicalize the resulting range. Otherwise we can do the
2765 conversion if the size of the range is less than what the
2766 precision of the target type can represent and the range is
2767 not an anti-range. */
2768 if ((vr0.type == VR_RANGE
2769 || vr0.type == VR_ANTI_RANGE)
2770 && TREE_CODE (vr0.min) == INTEGER_CST
2771 && TREE_CODE (vr0.max) == INTEGER_CST
2772 && (!is_overflow_infinity (vr0.min)
2773 || (vr0.type == VR_RANGE
2774 && TYPE_PRECISION (outer_type) > TYPE_PRECISION (inner_type)
2775 && needs_overflow_infinity (outer_type)
2776 && supports_overflow_infinity (outer_type)))
2777 && (!is_overflow_infinity (vr0.max)
2778 || (vr0.type == VR_RANGE
2779 && TYPE_PRECISION (outer_type) > TYPE_PRECISION (inner_type)
2780 && needs_overflow_infinity (outer_type)
2781 && supports_overflow_infinity (outer_type)))
2782 && (TYPE_PRECISION (outer_type) >= TYPE_PRECISION (inner_type)
2783 || (vr0.type == VR_RANGE
2784 && integer_zerop (int_const_binop (RSHIFT_EXPR,
2785 int_const_binop (MINUS_EXPR, vr0.max, vr0.min, 0),
2786 size_int (TYPE_PRECISION (outer_type)), 0)))))
2788 tree new_min, new_max;
2789 new_min = force_fit_type_double (outer_type,
2790 TREE_INT_CST_LOW (vr0.min),
2791 TREE_INT_CST_HIGH (vr0.min), 0, 0);
2792 new_max = force_fit_type_double (outer_type,
2793 TREE_INT_CST_LOW (vr0.max),
2794 TREE_INT_CST_HIGH (vr0.max), 0, 0);
2795 if (is_overflow_infinity (vr0.min))
2796 new_min = negative_overflow_infinity (outer_type);
2797 if (is_overflow_infinity (vr0.max))
2798 new_max = positive_overflow_infinity (outer_type);
2799 set_and_canonicalize_value_range (vr, vr0.type,
2800 new_min, new_max, NULL);
2804 set_value_range_to_varying (vr);
2808 /* Conversion of a VR_VARYING value to a wider type can result
2809 in a usable range. So wait until after we've handled conversions
2810 before dropping the result to VR_VARYING if we had a source
2811 operand that is VR_VARYING. */
2812 if (vr0.type == VR_VARYING)
2814 set_value_range_to_varying (vr);
2818 /* Apply the operation to each end of the range and see what we end
2820 if (code == NEGATE_EXPR
2821 && !TYPE_UNSIGNED (type))
2823 /* NEGATE_EXPR flips the range around. We need to treat
2824 TYPE_MIN_VALUE specially. */
2825 if (is_positive_overflow_infinity (vr0.max))
2826 min = negative_overflow_infinity (type);
2827 else if (is_negative_overflow_infinity (vr0.max))
2828 min = positive_overflow_infinity (type);
2829 else if (!vrp_val_is_min (vr0.max))
2830 min = fold_unary_to_constant (code, type, vr0.max);
2831 else if (needs_overflow_infinity (type))
2833 if (supports_overflow_infinity (type)
2834 && !is_overflow_infinity (vr0.min)
2835 && !vrp_val_is_min (vr0.min))
2836 min = positive_overflow_infinity (type);
2839 set_value_range_to_varying (vr);
2844 min = TYPE_MIN_VALUE (type);
2846 if (is_positive_overflow_infinity (vr0.min))
2847 max = negative_overflow_infinity (type);
2848 else if (is_negative_overflow_infinity (vr0.min))
2849 max = positive_overflow_infinity (type);
2850 else if (!vrp_val_is_min (vr0.min))
2851 max = fold_unary_to_constant (code, type, vr0.min);
2852 else if (needs_overflow_infinity (type))
2854 if (supports_overflow_infinity (type))
2855 max = positive_overflow_infinity (type);
2858 set_value_range_to_varying (vr);
2863 max = TYPE_MIN_VALUE (type);
2865 else if (code == NEGATE_EXPR
2866 && TYPE_UNSIGNED (type))
2868 if (!range_includes_zero_p (&vr0))
2870 max = fold_unary_to_constant (code, type, vr0.min);
2871 min = fold_unary_to_constant (code, type, vr0.max);
2875 if (range_is_null (&vr0))
2876 set_value_range_to_null (vr, type);
2878 set_value_range_to_varying (vr);
2882 else if (code == ABS_EXPR
2883 && !TYPE_UNSIGNED (type))
2885 /* -TYPE_MIN_VALUE = TYPE_MIN_VALUE with flag_wrapv so we can't get a
2887 if (!TYPE_OVERFLOW_UNDEFINED (type)
2888 && ((vr0.type == VR_RANGE
2889 && vrp_val_is_min (vr0.min))
2890 || (vr0.type == VR_ANTI_RANGE
2891 && !vrp_val_is_min (vr0.min)
2892 && !range_includes_zero_p (&vr0))))
2894 set_value_range_to_varying (vr);
2898 /* ABS_EXPR may flip the range around, if the original range
2899 included negative values. */
2900 if (is_overflow_infinity (vr0.min))
2901 min = positive_overflow_infinity (type);
2902 else if (!vrp_val_is_min (vr0.min))
2903 min = fold_unary_to_constant (code, type, vr0.min);
2904 else if (!needs_overflow_infinity (type))
2905 min = TYPE_MAX_VALUE (type);
2906 else if (supports_overflow_infinity (type))
2907 min = positive_overflow_infinity (type);
2910 set_value_range_to_varying (vr);
2914 if (is_overflow_infinity (vr0.max))
2915 max = positive_overflow_infinity (type);
2916 else if (!vrp_val_is_min (vr0.max))
2917 max = fold_unary_to_constant (code, type, vr0.max);
2918 else if (!needs_overflow_infinity (type))
2919 max = TYPE_MAX_VALUE (type);
2920 else if (supports_overflow_infinity (type)
2921 /* We shouldn't generate [+INF, +INF] as set_value_range
2922 doesn't like this and ICEs. */
2923 && !is_positive_overflow_infinity (min))
2924 max = positive_overflow_infinity (type);
2927 set_value_range_to_varying (vr);
2931 cmp = compare_values (min, max);
2933 /* If a VR_ANTI_RANGEs contains zero, then we have
2934 ~[-INF, min(MIN, MAX)]. */
2935 if (vr0.type == VR_ANTI_RANGE)
2937 if (range_includes_zero_p (&vr0))
2939 /* Take the lower of the two values. */
2943 /* Create ~[-INF, min (abs(MIN), abs(MAX))]
2944 or ~[-INF + 1, min (abs(MIN), abs(MAX))] when
2945 flag_wrapv is set and the original anti-range doesn't include
2946 TYPE_MIN_VALUE, remember -TYPE_MIN_VALUE = TYPE_MIN_VALUE. */
2947 if (TYPE_OVERFLOW_WRAPS (type))
2949 tree type_min_value = TYPE_MIN_VALUE (type);
2951 min = (vr0.min != type_min_value
2952 ? int_const_binop (PLUS_EXPR, type_min_value,
2953 integer_one_node, 0)
2958 if (overflow_infinity_range_p (&vr0))
2959 min = negative_overflow_infinity (type);
2961 min = TYPE_MIN_VALUE (type);
2966 /* All else has failed, so create the range [0, INF], even for
2967 flag_wrapv since TYPE_MIN_VALUE is in the original
2969 vr0.type = VR_RANGE;
2970 min = build_int_cst (type, 0);
2971 if (needs_overflow_infinity (type))
2973 if (supports_overflow_infinity (type))
2974 max = positive_overflow_infinity (type);
2977 set_value_range_to_varying (vr);
2982 max = TYPE_MAX_VALUE (type);
2986 /* If the range contains zero then we know that the minimum value in the
2987 range will be zero. */
2988 else if (range_includes_zero_p (&vr0))
2992 min = build_int_cst (type, 0);
2996 /* If the range was reversed, swap MIN and MAX. */
3007 /* Otherwise, operate on each end of the range. */
3008 min = fold_unary_to_constant (code, type, vr0.min);
3009 max = fold_unary_to_constant (code, type, vr0.max);
3011 if (needs_overflow_infinity (type))
3013 gcc_assert (code != NEGATE_EXPR && code != ABS_EXPR);
3015 /* If both sides have overflowed, we don't know
3017 if ((is_overflow_infinity (vr0.min)
3018 || TREE_OVERFLOW (min))
3019 && (is_overflow_infinity (vr0.max)
3020 || TREE_OVERFLOW (max)))
3022 set_value_range_to_varying (vr);
3026 if (is_overflow_infinity (vr0.min))
3028 else if (TREE_OVERFLOW (min))
3030 if (supports_overflow_infinity (type))
3031 min = (tree_int_cst_sgn (min) >= 0
3032 ? positive_overflow_infinity (TREE_TYPE (min))
3033 : negative_overflow_infinity (TREE_TYPE (min)));
3036 set_value_range_to_varying (vr);
3041 if (is_overflow_infinity (vr0.max))
3043 else if (TREE_OVERFLOW (max))
3045 if (supports_overflow_infinity (type))
3046 max = (tree_int_cst_sgn (max) >= 0
3047 ? positive_overflow_infinity (TREE_TYPE (max))
3048 : negative_overflow_infinity (TREE_TYPE (max)));
3051 set_value_range_to_varying (vr);
3058 cmp = compare_values (min, max);
3059 if (cmp == -2 || cmp == 1)
3061 /* If the new range has its limits swapped around (MIN > MAX),
3062 then the operation caused one of them to wrap around, mark
3063 the new range VARYING. */
3064 set_value_range_to_varying (vr);
3067 set_value_range (vr, vr0.type, min, max, NULL);
3071 /* Extract range information from a conditional expression EXPR based on
3072 the ranges of each of its operands and the expression code. */
3075 extract_range_from_cond_expr (value_range_t *vr, tree expr)
3078 value_range_t vr0 = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
3079 value_range_t vr1 = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
3081 /* Get value ranges for each operand. For constant operands, create
3082 a new value range with the operand to simplify processing. */
3083 op0 = COND_EXPR_THEN (expr);
3084 if (TREE_CODE (op0) == SSA_NAME)
3085 vr0 = *(get_value_range (op0));
3086 else if (is_gimple_min_invariant (op0))
3087 set_value_range_to_value (&vr0, op0, NULL);
3089 set_value_range_to_varying (&vr0);
3091 op1 = COND_EXPR_ELSE (expr);
3092 if (TREE_CODE (op1) == SSA_NAME)
3093 vr1 = *(get_value_range (op1));
3094 else if (is_gimple_min_invariant (op1))
3095 set_value_range_to_value (&vr1, op1, NULL);
3097 set_value_range_to_varying (&vr1);
3099 /* The resulting value range is the union of the operand ranges */
3100 vrp_meet (&vr0, &vr1);
3101 copy_value_range (vr, &vr0);
3105 /* Extract range information from a comparison expression EXPR based
3106 on the range of its operand and the expression code. */
3109 extract_range_from_comparison (value_range_t *vr, enum tree_code code,
3110 tree type, tree op0, tree op1)
3115 val = vrp_evaluate_conditional_warnv_with_ops (code, op0, op1, false, &sop,
3118 /* A disadvantage of using a special infinity as an overflow
3119 representation is that we lose the ability to record overflow
3120 when we don't have an infinity. So we have to ignore a result
3121 which relies on overflow. */
3123 if (val && !is_overflow_infinity (val) && !sop)
3125 /* Since this expression was found on the RHS of an assignment,
3126 its type may be different from _Bool. Convert VAL to EXPR's
3128 val = fold_convert (type, val);
3129 if (is_gimple_min_invariant (val))
3130 set_value_range_to_value (vr, val, vr->equiv);
3132 set_value_range (vr, VR_RANGE, val, val, vr->equiv);
3135 /* The result of a comparison is always true or false. */
3136 set_value_range_to_truthvalue (vr, type);
3139 /* Try to derive a nonnegative or nonzero range out of STMT relying
3140 primarily on generic routines in fold in conjunction with range data.
3141 Store the result in *VR */
3144 extract_range_basic (value_range_t *vr, gimple stmt)
3147 tree type = gimple_expr_type (stmt);
3149 if (INTEGRAL_TYPE_P (type)
3150 && gimple_stmt_nonnegative_warnv_p (stmt, &sop))
3151 set_value_range_to_nonnegative (vr, type,
3152 sop || stmt_overflow_infinity (stmt));
3153 else if (vrp_stmt_computes_nonzero (stmt, &sop)
3155 set_value_range_to_nonnull (vr, type);
3157 set_value_range_to_varying (vr);
3161 /* Try to compute a useful range out of assignment STMT and store it
3165 extract_range_from_assignment (value_range_t *vr, gimple stmt)
3167 enum tree_code code = gimple_assign_rhs_code (stmt);
3169 if (code == ASSERT_EXPR)
3170 extract_range_from_assert (vr, gimple_assign_rhs1 (stmt));
3171 else if (code == SSA_NAME)
3172 extract_range_from_ssa_name (vr, gimple_assign_rhs1 (stmt));
3173 else if (TREE_CODE_CLASS (code) == tcc_binary
3174 || code == TRUTH_AND_EXPR
3175 || code == TRUTH_OR_EXPR
3176 || code == TRUTH_XOR_EXPR)
3177 extract_range_from_binary_expr (vr, gimple_assign_rhs_code (stmt),
3178 gimple_expr_type (stmt),
3179 gimple_assign_rhs1 (stmt),
3180 gimple_assign_rhs2 (stmt));
3181 else if (TREE_CODE_CLASS (code) == tcc_unary)
3182 extract_range_from_unary_expr (vr, gimple_assign_rhs_code (stmt),
3183 gimple_expr_type (stmt),
3184 gimple_assign_rhs1 (stmt));
3185 else if (code == COND_EXPR)
3186 extract_range_from_cond_expr (vr, gimple_assign_rhs1 (stmt));
3187 else if (TREE_CODE_CLASS (code) == tcc_comparison)
3188 extract_range_from_comparison (vr, gimple_assign_rhs_code (stmt),
3189 gimple_expr_type (stmt),
3190 gimple_assign_rhs1 (stmt),
3191 gimple_assign_rhs2 (stmt));
3192 else if (get_gimple_rhs_class (code) == GIMPLE_SINGLE_RHS
3193 && is_gimple_min_invariant (gimple_assign_rhs1 (stmt)))
3194 set_value_range_to_value (vr, gimple_assign_rhs1 (stmt), NULL);
3196 set_value_range_to_varying (vr);
3198 if (vr->type == VR_VARYING)
3199 extract_range_basic (vr, stmt);
3202 /* Given a range VR, a LOOP and a variable VAR, determine whether it
3203 would be profitable to adjust VR using scalar evolution information
3204 for VAR. If so, update VR with the new limits. */
3207 adjust_range_with_scev (value_range_t *vr, struct loop *loop,
3208 gimple stmt, tree var)
3210 tree init, step, chrec, tmin, tmax, min, max, type, tem;
3211 enum ev_direction dir;
3213 /* TODO. Don't adjust anti-ranges. An anti-range may provide
3214 better opportunities than a regular range, but I'm not sure. */
3215 if (vr->type == VR_ANTI_RANGE)
3218 chrec = instantiate_parameters (loop, analyze_scalar_evolution (loop, var));
3220 /* Like in PR19590, scev can return a constant function. */
3221 if (is_gimple_min_invariant (chrec))
3223 set_value_range_to_value (vr, chrec, vr->equiv);
3227 if (TREE_CODE (chrec) != POLYNOMIAL_CHREC)
3230 init = initial_condition_in_loop_num (chrec, loop->num);
3231 tem = op_with_constant_singleton_value_range (init);
3234 step = evolution_part_in_loop_num (chrec, loop->num);
3235 tem = op_with_constant_singleton_value_range (step);
3239 /* If STEP is symbolic, we can't know whether INIT will be the
3240 minimum or maximum value in the range. Also, unless INIT is
3241 a simple expression, compare_values and possibly other functions
3242 in tree-vrp won't be able to handle it. */
3243 if (step == NULL_TREE
3244 || !is_gimple_min_invariant (step)
3245 || !valid_value_p (init))
3248 dir = scev_direction (chrec);
3249 if (/* Do not adjust ranges if we do not know whether the iv increases
3250 or decreases, ... */
3251 dir == EV_DIR_UNKNOWN
3252 /* ... or if it may wrap. */
3253 || scev_probably_wraps_p (init, step, stmt, get_chrec_loop (chrec),
3257 /* We use TYPE_MIN_VALUE and TYPE_MAX_VALUE here instead of
3258 negative_overflow_infinity and positive_overflow_infinity,
3259 because we have concluded that the loop probably does not
3262 type = TREE_TYPE (var);
3263 if (POINTER_TYPE_P (type) || !TYPE_MIN_VALUE (type))
3264 tmin = lower_bound_in_type (type, type);
3266 tmin = TYPE_MIN_VALUE (type);
3267 if (POINTER_TYPE_P (type) || !TYPE_MAX_VALUE (type))
3268 tmax = upper_bound_in_type (type, type);
3270 tmax = TYPE_MAX_VALUE (type);
3272 if (vr->type == VR_VARYING || vr->type == VR_UNDEFINED)
3277 /* For VARYING or UNDEFINED ranges, just about anything we get
3278 from scalar evolutions should be better. */
3280 if (dir == EV_DIR_DECREASES)
3285 /* If we would create an invalid range, then just assume we
3286 know absolutely nothing. This may be over-conservative,
3287 but it's clearly safe, and should happen only in unreachable
3288 parts of code, or for invalid programs. */
3289 if (compare_values (min, max) == 1)
3292 set_value_range (vr, VR_RANGE, min, max, vr->equiv);
3294 else if (vr->type == VR_RANGE)
3299 if (dir == EV_DIR_DECREASES)
3301 /* INIT is the maximum value. If INIT is lower than VR->MAX
3302 but no smaller than VR->MIN, set VR->MAX to INIT. */
3303 if (compare_values (init, max) == -1)
3307 /* If we just created an invalid range with the minimum
3308 greater than the maximum, we fail conservatively.
3309 This should happen only in unreachable
3310 parts of code, or for invalid programs. */
3311 if (compare_values (min, max) == 1)
3315 /* According to the loop information, the variable does not
3316 overflow. If we think it does, probably because of an
3317 overflow due to arithmetic on a different INF value,
3319 if (is_negative_overflow_infinity (min))
3324 /* If INIT is bigger than VR->MIN, set VR->MIN to INIT. */
3325 if (compare_values (init, min) == 1)
3329 /* Again, avoid creating invalid range by failing. */
3330 if (compare_values (min, max) == 1)
3334 if (is_positive_overflow_infinity (max))
3338 set_value_range (vr, VR_RANGE, min, max, vr->equiv);
3342 /* Return true if VAR may overflow at STMT. This checks any available
3343 loop information to see if we can determine that VAR does not
3347 vrp_var_may_overflow (tree var, gimple stmt)
3350 tree chrec, init, step;
3352 if (current_loops == NULL)
3355 l = loop_containing_stmt (stmt);
3360 chrec = instantiate_parameters (l, analyze_scalar_evolution (l, var));
3361 if (TREE_CODE (chrec) != POLYNOMIAL_CHREC)
3364 init = initial_condition_in_loop_num (chrec, l->num);
3365 step = evolution_part_in_loop_num (chrec, l->num);
3367 if (step == NULL_TREE
3368 || !is_gimple_min_invariant (step)
3369 || !valid_value_p (init))
3372 /* If we get here, we know something useful about VAR based on the
3373 loop information. If it wraps, it may overflow. */
3375 if (scev_probably_wraps_p (init, step, stmt, get_chrec_loop (chrec),
3379 if (dump_file && (dump_flags & TDF_DETAILS) != 0)
3381 print_generic_expr (dump_file, var, 0);
3382 fprintf (dump_file, ": loop information indicates does not overflow\n");
3389 /* Given two numeric value ranges VR0, VR1 and a comparison code COMP:
3391 - Return BOOLEAN_TRUE_NODE if VR0 COMP VR1 always returns true for
3392 all the values in the ranges.
3394 - Return BOOLEAN_FALSE_NODE if the comparison always returns false.
3396 - Return NULL_TREE if it is not always possible to determine the
3397 value of the comparison.
3399 Also set *STRICT_OVERFLOW_P to indicate whether a range with an
3400 overflow infinity was used in the test. */
3404 compare_ranges (enum tree_code comp, value_range_t *vr0, value_range_t *vr1,
3405 bool *strict_overflow_p)
3407 /* VARYING or UNDEFINED ranges cannot be compared. */
3408 if (vr0->type == VR_VARYING
3409 || vr0->type == VR_UNDEFINED
3410 || vr1->type == VR_VARYING
3411 || vr1->type == VR_UNDEFINED)
3414 /* Anti-ranges need to be handled separately. */
3415 if (vr0->type == VR_ANTI_RANGE || vr1->type == VR_ANTI_RANGE)
3417 /* If both are anti-ranges, then we cannot compute any
3419 if (vr0->type == VR_ANTI_RANGE && vr1->type == VR_ANTI_RANGE)
3422 /* These comparisons are never statically computable. */
3429 /* Equality can be computed only between a range and an
3430 anti-range. ~[VAL1, VAL2] == [VAL1, VAL2] is always false. */
3431 if (vr0->type == VR_RANGE)
3433 /* To simplify processing, make VR0 the anti-range. */
3434 value_range_t *tmp = vr0;
3439 gcc_assert (comp == NE_EXPR || comp == EQ_EXPR);
3441 if (compare_values_warnv (vr0->min, vr1->min, strict_overflow_p) == 0
3442 && compare_values_warnv (vr0->max, vr1->max, strict_overflow_p) == 0)
3443 return (comp == NE_EXPR) ? boolean_true_node : boolean_false_node;
3448 if (!usable_range_p (vr0, strict_overflow_p)
3449 || !usable_range_p (vr1, strict_overflow_p))
3452 /* Simplify processing. If COMP is GT_EXPR or GE_EXPR, switch the
3453 operands around and change the comparison code. */
3454 if (comp == GT_EXPR || comp == GE_EXPR)
3457 comp = (comp == GT_EXPR) ? LT_EXPR : LE_EXPR;
3463 if (comp == EQ_EXPR)
3465 /* Equality may only be computed if both ranges represent
3466 exactly one value. */
3467 if (compare_values_warnv (vr0->min, vr0->max, strict_overflow_p) == 0
3468 && compare_values_warnv (vr1->min, vr1->max, strict_overflow_p) == 0)
3470 int cmp_min = compare_values_warnv (vr0->min, vr1->min,
3472 int cmp_max = compare_values_warnv (vr0->max, vr1->max,
3474 if (cmp_min == 0 && cmp_max == 0)
3475 return boolean_true_node;
3476 else if (cmp_min != -2 && cmp_max != -2)
3477 return boolean_false_node;
3479 /* If [V0_MIN, V1_MAX] < [V1_MIN, V1_MAX] then V0 != V1. */
3480 else if (compare_values_warnv (vr0->min, vr1->max,
3481 strict_overflow_p) == 1
3482 || compare_values_warnv (vr1->min, vr0->max,
3483 strict_overflow_p) == 1)
3484 return boolean_false_node;
3488 else if (comp == NE_EXPR)
3492 /* If VR0 is completely to the left or completely to the right
3493 of VR1, they are always different. Notice that we need to
3494 make sure that both comparisons yield similar results to
3495 avoid comparing values that cannot be compared at
3497 cmp1 = compare_values_warnv (vr0->max, vr1->min, strict_overflow_p);
3498 cmp2 = compare_values_warnv (vr0->min, vr1->max, strict_overflow_p);
3499 if ((cmp1 == -1 && cmp2 == -1) || (cmp1 == 1 && cmp2 == 1))
3500 return boolean_true_node;
3502 /* If VR0 and VR1 represent a single value and are identical,
3504 else if (compare_values_warnv (vr0->min, vr0->max,
3505 strict_overflow_p) == 0
3506 && compare_values_warnv (vr1->min, vr1->max,
3507 strict_overflow_p) == 0
3508 && compare_values_warnv (vr0->min, vr1->min,
3509 strict_overflow_p) == 0
3510 && compare_values_warnv (vr0->max, vr1->max,
3511 strict_overflow_p) == 0)
3512 return boolean_false_node;
3514 /* Otherwise, they may or may not be different. */
3518 else if (comp == LT_EXPR || comp == LE_EXPR)
3522 /* If VR0 is to the left of VR1, return true. */
3523 tst = compare_values_warnv (vr0->max, vr1->min, strict_overflow_p);
3524 if ((comp == LT_EXPR && tst == -1)
3525 || (comp == LE_EXPR && (tst == -1 || tst == 0)))
3527 if (overflow_infinity_range_p (vr0)
3528 || overflow_infinity_range_p (vr1))
3529 *strict_overflow_p = true;
3530 return boolean_true_node;
3533 /* If VR0 is to the right of VR1, return false. */
3534 tst = compare_values_warnv (vr0->min, vr1->max, strict_overflow_p);
3535 if ((comp == LT_EXPR && (tst == 0 || tst == 1))
3536 || (comp == LE_EXPR && tst == 1))
3538 if (overflow_infinity_range_p (vr0)
3539 || overflow_infinity_range_p (vr1))
3540 *strict_overflow_p = true;
3541 return boolean_false_node;
3544 /* Otherwise, we don't know. */
3552 /* Given a value range VR, a value VAL and a comparison code COMP, return
3553 BOOLEAN_TRUE_NODE if VR COMP VAL always returns true for all the
3554 values in VR. Return BOOLEAN_FALSE_NODE if the comparison
3555 always returns false. Return NULL_TREE if it is not always
3556 possible to determine the value of the comparison. Also set
3557 *STRICT_OVERFLOW_P to indicate whether a range with an overflow
3558 infinity was used in the test. */
3561 compare_range_with_value (enum tree_code comp, value_range_t *vr, tree val,
3562 bool *strict_overflow_p)
3564 if (vr->type == VR_VARYING || vr->type == VR_UNDEFINED)
3567 /* Anti-ranges need to be handled separately. */
3568 if (vr->type == VR_ANTI_RANGE)
3570 /* For anti-ranges, the only predicates that we can compute at
3571 compile time are equality and inequality. */
3578 /* ~[VAL_1, VAL_2] OP VAL is known if VAL_1 <= VAL <= VAL_2. */
3579 if (value_inside_range (val, vr) == 1)
3580 return (comp == NE_EXPR) ? boolean_true_node : boolean_false_node;
3585 if (!usable_range_p (vr, strict_overflow_p))
3588 if (comp == EQ_EXPR)
3590 /* EQ_EXPR may only be computed if VR represents exactly
3592 if (compare_values_warnv (vr->min, vr->max, strict_overflow_p) == 0)
3594 int cmp = compare_values_warnv (vr->min, val, strict_overflow_p);
3596 return boolean_true_node;
3597 else if (cmp == -1 || cmp == 1 || cmp == 2)
3598 return boolean_false_node;
3600 else if (compare_values_warnv (val, vr->min, strict_overflow_p) == -1
3601 || compare_values_warnv (vr->max, val, strict_overflow_p) == -1)
3602 return boolean_false_node;
3606 else if (comp == NE_EXPR)
3608 /* If VAL is not inside VR, then they are always different. */
3609 if (compare_values_warnv (vr->max, val, strict_overflow_p) == -1
3610 || compare_values_warnv (vr->min, val, strict_overflow_p) == 1)
3611 return boolean_true_node;
3613 /* If VR represents exactly one value equal to VAL, then return
3615 if (compare_values_warnv (vr->min, vr->max, strict_overflow_p) == 0
3616 && compare_values_warnv (vr->min, val, strict_overflow_p) == 0)
3617 return boolean_false_node;
3619 /* Otherwise, they may or may not be different. */
3622 else if (comp == LT_EXPR || comp == LE_EXPR)
3626 /* If VR is to the left of VAL, return true. */
3627 tst = compare_values_warnv (vr->max, val, strict_overflow_p);
3628 if ((comp == LT_EXPR && tst == -1)
3629 || (comp == LE_EXPR && (tst == -1 || tst == 0)))
3631 if (overflow_infinity_range_p (vr))
3632 *strict_overflow_p = true;
3633 return boolean_true_node;
3636 /* If VR is to the right of VAL, return false. */
3637 tst = compare_values_warnv (vr->min, val, strict_overflow_p);
3638 if ((comp == LT_EXPR && (tst == 0 || tst == 1))
3639 || (comp == LE_EXPR && tst == 1))
3641 if (overflow_infinity_range_p (vr))
3642 *strict_overflow_p = true;
3643 return boolean_false_node;
3646 /* Otherwise, we don't know. */
3649 else if (comp == GT_EXPR || comp == GE_EXPR)
3653 /* If VR is to the right of VAL, return true. */
3654 tst = compare_values_warnv (vr->min, val, strict_overflow_p);
3655 if ((comp == GT_EXPR && tst == 1)
3656 || (comp == GE_EXPR && (tst == 0 || tst == 1)))
3658 if (overflow_infinity_range_p (vr))
3659 *strict_overflow_p = true;
3660 return boolean_true_node;
3663 /* If VR is to the left of VAL, return false. */
3664 tst = compare_values_warnv (vr->max, val, strict_overflow_p);
3665 if ((comp == GT_EXPR && (tst == -1 || tst == 0))
3666 || (comp == GE_EXPR && tst == -1))
3668 if (overflow_infinity_range_p (vr))
3669 *strict_overflow_p = true;
3670 return boolean_false_node;
3673 /* Otherwise, we don't know. */
3681 /* Debugging dumps. */
3683 void dump_value_range (FILE *, value_range_t *);
3684 void debug_value_range (value_range_t *);
3685 void dump_all_value_ranges (FILE *);
3686 void debug_all_value_ranges (void);
3687 void dump_vr_equiv (FILE *, bitmap);
3688 void debug_vr_equiv (bitmap);
3691 /* Dump value range VR to FILE. */
3694 dump_value_range (FILE *file, value_range_t *vr)
3697 fprintf (file, "[]");
3698 else if (vr->type == VR_UNDEFINED)
3699 fprintf (file, "UNDEFINED");
3700 else if (vr->type == VR_RANGE || vr->type == VR_ANTI_RANGE)
3702 tree type = TREE_TYPE (vr->min);
3704 fprintf (file, "%s[", (vr->type == VR_ANTI_RANGE) ? "~" : "");
3706 if (is_negative_overflow_infinity (vr->min))
3707 fprintf (file, "-INF(OVF)");
3708 else if (INTEGRAL_TYPE_P (type)
3709 && !TYPE_UNSIGNED (type)
3710 && vrp_val_is_min (vr->min))
3711 fprintf (file, "-INF");
3713 print_generic_expr (file, vr->min, 0);
3715 fprintf (file, ", ");
3717 if (is_positive_overflow_infinity (vr->max))
3718 fprintf (file, "+INF(OVF)");
3719 else if (INTEGRAL_TYPE_P (type)
3720 && vrp_val_is_max (vr->max))
3721 fprintf (file, "+INF");
3723 print_generic_expr (file, vr->max, 0);
3725 fprintf (file, "]");
3732 fprintf (file, " EQUIVALENCES: { ");
3734 EXECUTE_IF_SET_IN_BITMAP (vr->equiv, 0, i, bi)
3736 print_generic_expr (file, ssa_name (i), 0);
3737 fprintf (file, " ");
3741 fprintf (file, "} (%u elements)", c);
3744 else if (vr->type == VR_VARYING)
3745 fprintf (file, "VARYING");
3747 fprintf (file, "INVALID RANGE");
3751 /* Dump value range VR to stderr. */
3754 debug_value_range (value_range_t *vr)
3756 dump_value_range (stderr, vr);
3757 fprintf (stderr, "\n");
3761 /* Dump value ranges of all SSA_NAMEs to FILE. */
3764 dump_all_value_ranges (FILE *file)
3768 for (i = 0; i < num_ssa_names; i++)
3772 print_generic_expr (file, ssa_name (i), 0);
3773 fprintf (file, ": ");
3774 dump_value_range (file, vr_value[i]);
3775 fprintf (file, "\n");
3779 fprintf (file, "\n");
3783 /* Dump all value ranges to stderr. */
3786 debug_all_value_ranges (void)
3788 dump_all_value_ranges (stderr);
3792 /* Given a COND_EXPR COND of the form 'V OP W', and an SSA name V,
3793 create a new SSA name N and return the assertion assignment
3794 'V = ASSERT_EXPR <V, V OP W>'. */
3797 build_assert_expr_for (tree cond, tree v)
3802 gcc_assert (TREE_CODE (v) == SSA_NAME);
3803 n = duplicate_ssa_name (v, NULL);
3805 if (COMPARISON_CLASS_P (cond))
3807 tree a = build2 (ASSERT_EXPR, TREE_TYPE (v), v, cond);
3808 assertion = gimple_build_assign (n, a);
3810 else if (TREE_CODE (cond) == TRUTH_NOT_EXPR)
3812 /* Given !V, build the assignment N = false. */
3813 tree op0 = TREE_OPERAND (cond, 0);
3814 gcc_assert (op0 == v);
3815 assertion = gimple_build_assign (n, boolean_false_node);
3817 else if (TREE_CODE (cond) == SSA_NAME)
3819 /* Given V, build the assignment N = true. */
3820 gcc_assert (v == cond);
3821 assertion = gimple_build_assign (n, boolean_true_node);
3826 SSA_NAME_DEF_STMT (n) = assertion;
3828 /* The new ASSERT_EXPR, creates a new SSA name that replaces the
3829 operand of the ASSERT_EXPR. Register the new name and the old one
3830 in the replacement table so that we can fix the SSA web after
3831 adding all the ASSERT_EXPRs. */
3832 register_new_name_mapping (n, v);
3838 /* Return false if EXPR is a predicate expression involving floating
3842 fp_predicate (gimple stmt)
3844 GIMPLE_CHECK (stmt, GIMPLE_COND);
3846 return FLOAT_TYPE_P (TREE_TYPE (gimple_cond_lhs (stmt)));
3850 /* If the range of values taken by OP can be inferred after STMT executes,
3851 return the comparison code (COMP_CODE_P) and value (VAL_P) that
3852 describes the inferred range. Return true if a range could be
3856 infer_value_range (gimple stmt, tree op, enum tree_code *comp_code_p, tree *val_p)
3859 *comp_code_p = ERROR_MARK;
3861 /* Do not attempt to infer anything in names that flow through
3863 if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (op))
3866 /* Similarly, don't infer anything from statements that may throw
3868 if (stmt_could_throw_p (stmt))
3871 /* If STMT is the last statement of a basic block with no
3872 successors, there is no point inferring anything about any of its
3873 operands. We would not be able to find a proper insertion point
3874 for the assertion, anyway. */
3875 if (stmt_ends_bb_p (stmt) && EDGE_COUNT (gimple_bb (stmt)->succs) == 0)
3878 /* We can only assume that a pointer dereference will yield
3879 non-NULL if -fdelete-null-pointer-checks is enabled. */
3880 if (flag_delete_null_pointer_checks
3881 && POINTER_TYPE_P (TREE_TYPE (op))
3882 && gimple_code (stmt) != GIMPLE_ASM)
3884 unsigned num_uses, num_loads, num_stores;
3886 count_uses_and_derefs (op, stmt, &num_uses, &num_loads, &num_stores);
3887 if (num_loads + num_stores > 0)
3889 *val_p = build_int_cst (TREE_TYPE (op), 0);
3890 *comp_code_p = NE_EXPR;
3899 void dump_asserts_for (FILE *, tree);
3900 void debug_asserts_for (tree);
3901 void dump_all_asserts (FILE *);
3902 void debug_all_asserts (void);
3904 /* Dump all the registered assertions for NAME to FILE. */
3907 dump_asserts_for (FILE *file, tree name)
3911 fprintf (file, "Assertions to be inserted for ");
3912 print_generic_expr (file, name, 0);
3913 fprintf (file, "\n");
3915 loc = asserts_for[SSA_NAME_VERSION (name)];
3918 fprintf (file, "\t");
3919 print_gimple_stmt (file, gsi_stmt (loc->si), 0, 0);
3920 fprintf (file, "\n\tBB #%d", loc->bb->index);
3923 fprintf (file, "\n\tEDGE %d->%d", loc->e->src->index,
3924 loc->e->dest->index);
3925 dump_edge_info (file, loc->e, 0);
3927 fprintf (file, "\n\tPREDICATE: ");
3928 print_generic_expr (file, name, 0);
3929 fprintf (file, " %s ", tree_code_name[(int)loc->comp_code]);
3930 print_generic_expr (file, loc->val, 0);
3931 fprintf (file, "\n\n");
3935 fprintf (file, "\n");
3939 /* Dump all the registered assertions for NAME to stderr. */
3942 debug_asserts_for (tree name)
3944 dump_asserts_for (stderr, name);
3948 /* Dump all the registered assertions for all the names to FILE. */
3951 dump_all_asserts (FILE *file)
3956 fprintf (file, "\nASSERT_EXPRs to be inserted\n\n");
3957 EXECUTE_IF_SET_IN_BITMAP (need_assert_for, 0, i, bi)
3958 dump_asserts_for (file, ssa_name (i));
3959 fprintf (file, "\n");
3963 /* Dump all the registered assertions for all the names to stderr. */
3966 debug_all_asserts (void)
3968 dump_all_asserts (stderr);
3972 /* If NAME doesn't have an ASSERT_EXPR registered for asserting
3973 'EXPR COMP_CODE VAL' at a location that dominates block BB or
3974 E->DEST, then register this location as a possible insertion point
3975 for ASSERT_EXPR <NAME, EXPR COMP_CODE VAL>.
3977 BB, E and SI provide the exact insertion point for the new
3978 ASSERT_EXPR. If BB is NULL, then the ASSERT_EXPR is to be inserted
3979 on edge E. Otherwise, if E is NULL, the ASSERT_EXPR is inserted on
3980 BB. If SI points to a COND_EXPR or a SWITCH_EXPR statement, then E
3981 must not be NULL. */
3984 register_new_assert_for (tree name, tree expr,
3985 enum tree_code comp_code,
3989 gimple_stmt_iterator si)
3991 assert_locus_t n, loc, last_loc;
3992 basic_block dest_bb;
3994 #if defined ENABLE_CHECKING
3995 gcc_assert (bb == NULL || e == NULL);
3998 gcc_assert (gimple_code (gsi_stmt (si)) != GIMPLE_COND
3999 && gimple_code (gsi_stmt (si)) != GIMPLE_SWITCH);
4002 /* Never build an assert comparing against an integer constant with
4003 TREE_OVERFLOW set. This confuses our undefined overflow warning
4005 if (TREE_CODE (val) == INTEGER_CST
4006 && TREE_OVERFLOW (val))
4007 val = build_int_cst_wide (TREE_TYPE (val),
4008 TREE_INT_CST_LOW (val), TREE_INT_CST_HIGH (val));
4010 /* The new assertion A will be inserted at BB or E. We need to
4011 determine if the new location is dominated by a previously
4012 registered location for A. If we are doing an edge insertion,
4013 assume that A will be inserted at E->DEST. Note that this is not
4016 If E is a critical edge, it will be split. But even if E is
4017 split, the new block will dominate the same set of blocks that
4020 The reverse, however, is not true, blocks dominated by E->DEST
4021 will not be dominated by the new block created to split E. So,
4022 if the insertion location is on a critical edge, we will not use
4023 the new location to move another assertion previously registered
4024 at a block dominated by E->DEST. */
4025 dest_bb = (bb) ? bb : e->dest;
4027 /* If NAME already has an ASSERT_EXPR registered for COMP_CODE and
4028 VAL at a block dominating DEST_BB, then we don't need to insert a new
4029 one. Similarly, if the same assertion already exists at a block
4030 dominated by DEST_BB and the new location is not on a critical
4031 edge, then update the existing location for the assertion (i.e.,
4032 move the assertion up in the dominance tree).
4034 Note, this is implemented as a simple linked list because there
4035 should not be more than a handful of assertions registered per
4036 name. If this becomes a performance problem, a table hashed by
4037 COMP_CODE and VAL could be implemented. */
4038 loc = asserts_for[SSA_NAME_VERSION (name)];
4042 if (loc->comp_code == comp_code
4044 || operand_equal_p (loc->val, val, 0))
4045 && (loc->expr == expr
4046 || operand_equal_p (loc->expr, expr, 0)))
4048 /* If the assertion NAME COMP_CODE VAL has already been
4049 registered at a basic block that dominates DEST_BB, then
4050 we don't need to insert the same assertion again. Note
4051 that we don't check strict dominance here to avoid
4052 replicating the same assertion inside the same basic
4053 block more than once (e.g., when a pointer is
4054 dereferenced several times inside a block).
4056 An exception to this rule are edge insertions. If the
4057 new assertion is to be inserted on edge E, then it will
4058 dominate all the other insertions that we may want to
4059 insert in DEST_BB. So, if we are doing an edge
4060 insertion, don't do this dominance check. */
4062 && dominated_by_p (CDI_DOMINATORS, dest_bb, loc->bb))
4065 /* Otherwise, if E is not a critical edge and DEST_BB
4066 dominates the existing location for the assertion, move
4067 the assertion up in the dominance tree by updating its
4068 location information. */
4069 if ((e == NULL || !EDGE_CRITICAL_P (e))
4070 && dominated_by_p (CDI_DOMINATORS, loc->bb, dest_bb))
4079 /* Update the last node of the list and move to the next one. */
4084 /* If we didn't find an assertion already registered for
4085 NAME COMP_CODE VAL, add a new one at the end of the list of
4086 assertions associated with NAME. */
4087 n = XNEW (struct assert_locus_d);
4091 n->comp_code = comp_code;
4099 asserts_for[SSA_NAME_VERSION (name)] = n;
4101 bitmap_set_bit (need_assert_for, SSA_NAME_VERSION (name));
4104 /* (COND_OP0 COND_CODE COND_OP1) is a predicate which uses NAME.
4105 Extract a suitable test code and value and store them into *CODE_P and
4106 *VAL_P so the predicate is normalized to NAME *CODE_P *VAL_P.
4108 If no extraction was possible, return FALSE, otherwise return TRUE.
4110 If INVERT is true, then we invert the result stored into *CODE_P. */
4113 extract_code_and_val_from_cond_with_ops (tree name, enum tree_code cond_code,
4114 tree cond_op0, tree cond_op1,
4115 bool invert, enum tree_code *code_p,
4118 enum tree_code comp_code;
4121 /* Otherwise, we have a comparison of the form NAME COMP VAL
4122 or VAL COMP NAME. */
4123 if (name == cond_op1)
4125 /* If the predicate is of the form VAL COMP NAME, flip
4126 COMP around because we need to register NAME as the
4127 first operand in the predicate. */
4128 comp_code = swap_tree_comparison (cond_code);
4133 /* The comparison is of the form NAME COMP VAL, so the
4134 comparison code remains unchanged. */
4135 comp_code = cond_code;
4139 /* Invert the comparison code as necessary. */
4141 comp_code = invert_tree_comparison (comp_code, 0);
4143 /* VRP does not handle float types. */
4144 if (SCALAR_FLOAT_TYPE_P (TREE_TYPE (val)))
4147 /* Do not register always-false predicates.
4148 FIXME: this works around a limitation in fold() when dealing with
4149 enumerations. Given 'enum { N1, N2 } x;', fold will not
4150 fold 'if (x > N2)' to 'if (0)'. */
4151 if ((comp_code == GT_EXPR || comp_code == LT_EXPR)
4152 && INTEGRAL_TYPE_P (TREE_TYPE (val)))
4154 tree min = TYPE_MIN_VALUE (TREE_TYPE (val));
4155 tree max = TYPE_MAX_VALUE (TREE_TYPE (val));
4157 if (comp_code == GT_EXPR
4159 || compare_values (val, max) == 0))
4162 if (comp_code == LT_EXPR
4164 || compare_values (val, min) == 0))
4167 *code_p = comp_code;
4172 /* Try to register an edge assertion for SSA name NAME on edge E for
4173 the condition COND contributing to the conditional jump pointed to by BSI.
4174 Invert the condition COND if INVERT is true.
4175 Return true if an assertion for NAME could be registered. */
4178 register_edge_assert_for_2 (tree name, edge e, gimple_stmt_iterator bsi,
4179 enum tree_code cond_code,
4180 tree cond_op0, tree cond_op1, bool invert)
4183 enum tree_code comp_code;
4184 bool retval = false;
4186 if (!extract_code_and_val_from_cond_with_ops (name, cond_code,
4189 invert, &comp_code, &val))
4192 /* Only register an ASSERT_EXPR if NAME was found in the sub-graph
4193 reachable from E. */
4194 if (live_on_edge (e, name)
4195 && !has_single_use (name))
4197 register_new_assert_for (name, name, comp_code, val, NULL, e, bsi);
4201 /* In the case of NAME <= CST and NAME being defined as
4202 NAME = (unsigned) NAME2 + CST2 we can assert NAME2 >= -CST2
4203 and NAME2 <= CST - CST2. We can do the same for NAME > CST.
4204 This catches range and anti-range tests. */
4205 if ((comp_code == LE_EXPR
4206 || comp_code == GT_EXPR)
4207 && TREE_CODE (val) == INTEGER_CST
4208 && TYPE_UNSIGNED (TREE_TYPE (val)))
4210 gimple def_stmt = SSA_NAME_DEF_STMT (name);
4211 tree cst2 = NULL_TREE, name2 = NULL_TREE, name3 = NULL_TREE;
4213 /* Extract CST2 from the (optional) addition. */
4214 if (is_gimple_assign (def_stmt)
4215 && gimple_assign_rhs_code (def_stmt) == PLUS_EXPR)
4217 name2 = gimple_assign_rhs1 (def_stmt);
4218 cst2 = gimple_assign_rhs2 (def_stmt);
4219 if (TREE_CODE (name2) == SSA_NAME
4220 && TREE_CODE (cst2) == INTEGER_CST)
4221 def_stmt = SSA_NAME_DEF_STMT (name2);
4224 /* Extract NAME2 from the (optional) sign-changing cast. */
4225 if (gimple_assign_cast_p (def_stmt))
4227 if (CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (def_stmt))
4228 && ! TYPE_UNSIGNED (TREE_TYPE (gimple_assign_rhs1 (def_stmt)))
4229 && (TYPE_PRECISION (gimple_expr_type (def_stmt))
4230 == TYPE_PRECISION (TREE_TYPE (gimple_assign_rhs1 (def_stmt)))))
4231 name3 = gimple_assign_rhs1 (def_stmt);
4234 /* If name3 is used later, create an ASSERT_EXPR for it. */
4235 if (name3 != NULL_TREE
4236 && TREE_CODE (name3) == SSA_NAME
4237 && (cst2 == NULL_TREE
4238 || TREE_CODE (cst2) == INTEGER_CST)
4239 && INTEGRAL_TYPE_P (TREE_TYPE (name3))
4240 && live_on_edge (e, name3)
4241 && !has_single_use (name3))
4245 /* Build an expression for the range test. */
4246 tmp = build1 (NOP_EXPR, TREE_TYPE (name), name3);
4247 if (cst2 != NULL_TREE)
4248 tmp = build2 (PLUS_EXPR, TREE_TYPE (name), tmp, cst2);
4252 fprintf (dump_file, "Adding assert for ");
4253 print_generic_expr (dump_file, name3, 0);
4254 fprintf (dump_file, " from ");
4255 print_generic_expr (dump_file, tmp, 0);
4256 fprintf (dump_file, "\n");
4259 register_new_assert_for (name3, tmp, comp_code, val, NULL, e, bsi);
4264 /* If name2 is used later, create an ASSERT_EXPR for it. */
4265 if (name2 != NULL_TREE
4266 && TREE_CODE (name2) == SSA_NAME
4267 && TREE_CODE (cst2) == INTEGER_CST
4268 && INTEGRAL_TYPE_P (TREE_TYPE (name2))
4269 && live_on_edge (e, name2)
4270 && !has_single_use (name2))
4274 /* Build an expression for the range test. */
4276 if (TREE_TYPE (name) != TREE_TYPE (name2))
4277 tmp = build1 (NOP_EXPR, TREE_TYPE (name), tmp);
4278 if (cst2 != NULL_TREE)
4279 tmp = build2 (PLUS_EXPR, TREE_TYPE (name), tmp, cst2);
4283 fprintf (dump_file, "Adding assert for ");
4284 print_generic_expr (dump_file, name2, 0);
4285 fprintf (dump_file, " from ");
4286 print_generic_expr (dump_file, tmp, 0);
4287 fprintf (dump_file, "\n");
4290 register_new_assert_for (name2, tmp, comp_code, val, NULL, e, bsi);
4299 /* OP is an operand of a truth value expression which is known to have
4300 a particular value. Register any asserts for OP and for any
4301 operands in OP's defining statement.
4303 If CODE is EQ_EXPR, then we want to register OP is zero (false),
4304 if CODE is NE_EXPR, then we want to register OP is nonzero (true). */
4307 register_edge_assert_for_1 (tree op, enum tree_code code,
4308 edge e, gimple_stmt_iterator bsi)
4310 bool retval = false;
4313 enum tree_code rhs_code;
4315 /* We only care about SSA_NAMEs. */
4316 if (TREE_CODE (op) != SSA_NAME)
4319 /* We know that OP will have a zero or nonzero value. If OP is used
4320 more than once go ahead and register an assert for OP.
4322 The FOUND_IN_SUBGRAPH support is not helpful in this situation as
4323 it will always be set for OP (because OP is used in a COND_EXPR in
4325 if (!has_single_use (op))
4327 val = build_int_cst (TREE_TYPE (op), 0);
4328 register_new_assert_for (op, op, code, val, NULL, e, bsi);
4332 /* Now look at how OP is set. If it's set from a comparison,
4333 a truth operation or some bit operations, then we may be able
4334 to register information about the operands of that assignment. */
4335 op_def = SSA_NAME_DEF_STMT (op);
4336 if (gimple_code (op_def) != GIMPLE_ASSIGN)
4339 rhs_code = gimple_assign_rhs_code (op_def);
4341 if (TREE_CODE_CLASS (rhs_code) == tcc_comparison)
4343 bool invert = (code == EQ_EXPR ? true : false);
4344 tree op0 = gimple_assign_rhs1 (op_def);
4345 tree op1 = gimple_assign_rhs2 (op_def);
4347 if (TREE_CODE (op0) == SSA_NAME)
4348 retval |= register_edge_assert_for_2 (op0, e, bsi, rhs_code, op0, op1,
4350 if (TREE_CODE (op1) == SSA_NAME)
4351 retval |= register_edge_assert_for_2 (op1, e, bsi, rhs_code, op0, op1,
4354 else if ((code == NE_EXPR
4355 && (gimple_assign_rhs_code (op_def) == TRUTH_AND_EXPR
4356 || gimple_assign_rhs_code (op_def) == BIT_AND_EXPR))
4358 && (gimple_assign_rhs_code (op_def) == TRUTH_OR_EXPR
4359 || gimple_assign_rhs_code (op_def) == BIT_IOR_EXPR)))
4361 /* Recurse on each operand. */
4362 retval |= register_edge_assert_for_1 (gimple_assign_rhs1 (op_def),
4364 retval |= register_edge_assert_for_1 (gimple_assign_rhs2 (op_def),
4367 else if (gimple_assign_rhs_code (op_def) == TRUTH_NOT_EXPR)
4369 /* Recurse, flipping CODE. */
4370 code = invert_tree_comparison (code, false);
4371 retval |= register_edge_assert_for_1 (gimple_assign_rhs1 (op_def),
4374 else if (gimple_assign_rhs_code (op_def) == SSA_NAME)
4376 /* Recurse through the copy. */
4377 retval |= register_edge_assert_for_1 (gimple_assign_rhs1 (op_def),
4380 else if (CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (op_def)))
4382 /* Recurse through the type conversion. */
4383 retval |= register_edge_assert_for_1 (gimple_assign_rhs1 (op_def),
4390 /* Try to register an edge assertion for SSA name NAME on edge E for
4391 the condition COND contributing to the conditional jump pointed to by SI.
4392 Return true if an assertion for NAME could be registered. */
4395 register_edge_assert_for (tree name, edge e, gimple_stmt_iterator si,
4396 enum tree_code cond_code, tree cond_op0,
4400 enum tree_code comp_code;
4401 bool retval = false;
4402 bool is_else_edge = (e->flags & EDGE_FALSE_VALUE) != 0;
4404 /* Do not attempt to infer anything in names that flow through
4406 if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (name))
4409 if (!extract_code_and_val_from_cond_with_ops (name, cond_code,
4415 /* Register ASSERT_EXPRs for name. */
4416 retval |= register_edge_assert_for_2 (name, e, si, cond_code, cond_op0,
4417 cond_op1, is_else_edge);
4420 /* If COND is effectively an equality test of an SSA_NAME against
4421 the value zero or one, then we may be able to assert values
4422 for SSA_NAMEs which flow into COND. */
4424 /* In the case of NAME == 1 or NAME != 0, for TRUTH_AND_EXPR defining
4425 statement of NAME we can assert both operands of the TRUTH_AND_EXPR
4426 have nonzero value. */
4427 if (((comp_code == EQ_EXPR && integer_onep (val))
4428 || (comp_code == NE_EXPR && integer_zerop (val))))
4430 gimple def_stmt = SSA_NAME_DEF_STMT (name);
4432 if (is_gimple_assign (def_stmt)
4433 && (gimple_assign_rhs_code (def_stmt) == TRUTH_AND_EXPR
4434 || gimple_assign_rhs_code (def_stmt) == BIT_AND_EXPR))
4436 tree op0 = gimple_assign_rhs1 (def_stmt);
4437 tree op1 = gimple_assign_rhs2 (def_stmt);
4438 retval |= register_edge_assert_for_1 (op0, NE_EXPR, e, si);
4439 retval |= register_edge_assert_for_1 (op1, NE_EXPR, e, si);
4443 /* In the case of NAME == 0 or NAME != 1, for TRUTH_OR_EXPR defining
4444 statement of NAME we can assert both operands of the TRUTH_OR_EXPR
4446 if (((comp_code == EQ_EXPR && integer_zerop (val))
4447 || (comp_code == NE_EXPR && integer_onep (val))))
4449 gimple def_stmt = SSA_NAME_DEF_STMT (name);
4451 if (is_gimple_assign (def_stmt)
4452 && (gimple_assign_rhs_code (def_stmt) == TRUTH_OR_EXPR
4453 /* For BIT_IOR_EXPR only if NAME == 0 both operands have
4454 necessarily zero value. */
4455 || (comp_code == EQ_EXPR
4456 && (gimple_assign_rhs_code (def_stmt) == BIT_IOR_EXPR))))
4458 tree op0 = gimple_assign_rhs1 (def_stmt);
4459 tree op1 = gimple_assign_rhs2 (def_stmt);
4460 retval |= register_edge_assert_for_1 (op0, EQ_EXPR, e, si);
4461 retval |= register_edge_assert_for_1 (op1, EQ_EXPR, e, si);
4469 /* Determine whether the outgoing edges of BB should receive an
4470 ASSERT_EXPR for each of the operands of BB's LAST statement.
4471 The last statement of BB must be a COND_EXPR.
4473 If any of the sub-graphs rooted at BB have an interesting use of
4474 the predicate operands, an assert location node is added to the
4475 list of assertions for the corresponding operands. */
4478 find_conditional_asserts (basic_block bb, gimple last)
4481 gimple_stmt_iterator bsi;
4487 need_assert = false;
4488 bsi = gsi_for_stmt (last);
4490 /* Look for uses of the operands in each of the sub-graphs
4491 rooted at BB. We need to check each of the outgoing edges
4492 separately, so that we know what kind of ASSERT_EXPR to
4494 FOR_EACH_EDGE (e, ei, bb->succs)
4499 /* Register the necessary assertions for each operand in the
4500 conditional predicate. */
4501 FOR_EACH_SSA_TREE_OPERAND (op, last, iter, SSA_OP_USE)
4503 need_assert |= register_edge_assert_for (op, e, bsi,
4504 gimple_cond_code (last),
4505 gimple_cond_lhs (last),
4506 gimple_cond_rhs (last));
4513 /* Compare two case labels sorting first by the destination label uid
4514 and then by the case value. */
4517 compare_case_labels (const void *p1, const void *p2)
4519 const_tree const case1 = *(const_tree const*)p1;
4520 const_tree const case2 = *(const_tree const*)p2;
4521 unsigned int uid1 = DECL_UID (CASE_LABEL (case1));
4522 unsigned int uid2 = DECL_UID (CASE_LABEL (case2));
4526 else if (uid1 == uid2)
4528 /* Make sure the default label is first in a group. */
4529 if (!CASE_LOW (case1))
4531 else if (!CASE_LOW (case2))
4534 return tree_int_cst_compare (CASE_LOW (case1), CASE_LOW (case2));
4540 /* Determine whether the outgoing edges of BB should receive an
4541 ASSERT_EXPR for each of the operands of BB's LAST statement.
4542 The last statement of BB must be a SWITCH_EXPR.
4544 If any of the sub-graphs rooted at BB have an interesting use of
4545 the predicate operands, an assert location node is added to the
4546 list of assertions for the corresponding operands. */
4549 find_switch_asserts (basic_block bb, gimple last)
4552 gimple_stmt_iterator bsi;
4556 size_t n = gimple_switch_num_labels(last);
4557 #if GCC_VERSION >= 4000
4560 /* Work around GCC 3.4 bug (PR 37086). */
4561 volatile unsigned int idx;
4564 need_assert = false;
4565 bsi = gsi_for_stmt (last);
4566 op = gimple_switch_index (last);
4567 if (TREE_CODE (op) != SSA_NAME)
4570 /* Build a vector of case labels sorted by destination label. */
4571 vec2 = make_tree_vec (n);
4572 for (idx = 0; idx < n; ++idx)
4573 TREE_VEC_ELT (vec2, idx) = gimple_switch_label (last, idx);
4574 qsort (&TREE_VEC_ELT (vec2, 0), n, sizeof (tree), compare_case_labels);
4576 for (idx = 0; idx < n; ++idx)
4579 tree cl = TREE_VEC_ELT (vec2, idx);
4581 min = CASE_LOW (cl);
4582 max = CASE_HIGH (cl);
4584 /* If there are multiple case labels with the same destination
4585 we need to combine them to a single value range for the edge. */
4587 && CASE_LABEL (cl) == CASE_LABEL (TREE_VEC_ELT (vec2, idx + 1)))
4589 /* Skip labels until the last of the group. */
4593 && CASE_LABEL (cl) == CASE_LABEL (TREE_VEC_ELT (vec2, idx)));
4596 /* Pick up the maximum of the case label range. */
4597 if (CASE_HIGH (TREE_VEC_ELT (vec2, idx)))
4598 max = CASE_HIGH (TREE_VEC_ELT (vec2, idx));
4600 max = CASE_LOW (TREE_VEC_ELT (vec2, idx));
4603 /* Nothing to do if the range includes the default label until we
4604 can register anti-ranges. */
4605 if (min == NULL_TREE)
4608 /* Find the edge to register the assert expr on. */
4609 e = find_edge (bb, label_to_block (CASE_LABEL (cl)));
4611 /* Register the necessary assertions for the operand in the
4613 need_assert |= register_edge_assert_for (op, e, bsi,
4614 max ? GE_EXPR : EQ_EXPR,
4616 fold_convert (TREE_TYPE (op),
4620 need_assert |= register_edge_assert_for (op, e, bsi, LE_EXPR,
4622 fold_convert (TREE_TYPE (op),
4631 /* Traverse all the statements in block BB looking for statements that
4632 may generate useful assertions for the SSA names in their operand.
4633 If a statement produces a useful assertion A for name N_i, then the
4634 list of assertions already generated for N_i is scanned to
4635 determine if A is actually needed.
4637 If N_i already had the assertion A at a location dominating the
4638 current location, then nothing needs to be done. Otherwise, the
4639 new location for A is recorded instead.
4641 1- For every statement S in BB, all the variables used by S are
4642 added to bitmap FOUND_IN_SUBGRAPH.
4644 2- If statement S uses an operand N in a way that exposes a known
4645 value range for N, then if N was not already generated by an
4646 ASSERT_EXPR, create a new assert location for N. For instance,
4647 if N is a pointer and the statement dereferences it, we can
4648 assume that N is not NULL.
4650 3- COND_EXPRs are a special case of #2. We can derive range
4651 information from the predicate but need to insert different
4652 ASSERT_EXPRs for each of the sub-graphs rooted at the
4653 conditional block. If the last statement of BB is a conditional
4654 expression of the form 'X op Y', then
4656 a) Remove X and Y from the set FOUND_IN_SUBGRAPH.
4658 b) If the conditional is the only entry point to the sub-graph
4659 corresponding to the THEN_CLAUSE, recurse into it. On
4660 return, if X and/or Y are marked in FOUND_IN_SUBGRAPH, then
4661 an ASSERT_EXPR is added for the corresponding variable.
4663 c) Repeat step (b) on the ELSE_CLAUSE.
4665 d) Mark X and Y in FOUND_IN_SUBGRAPH.
4674 In this case, an assertion on the THEN clause is useful to
4675 determine that 'a' is always 9 on that edge. However, an assertion
4676 on the ELSE clause would be unnecessary.
4678 4- If BB does not end in a conditional expression, then we recurse
4679 into BB's dominator children.
4681 At the end of the recursive traversal, every SSA name will have a
4682 list of locations where ASSERT_EXPRs should be added. When a new
4683 location for name N is found, it is registered by calling
4684 register_new_assert_for. That function keeps track of all the
4685 registered assertions to prevent adding unnecessary assertions.
4686 For instance, if a pointer P_4 is dereferenced more than once in a
4687 dominator tree, only the location dominating all the dereference of
4688 P_4 will receive an ASSERT_EXPR.
4690 If this function returns true, then it means that there are names
4691 for which we need to generate ASSERT_EXPRs. Those assertions are
4692 inserted by process_assert_insertions. */
4695 find_assert_locations_1 (basic_block bb, sbitmap live)
4697 gimple_stmt_iterator si;
4702 need_assert = false;
4703 last = last_stmt (bb);
4705 /* If BB's last statement is a conditional statement involving integer
4706 operands, determine if we need to add ASSERT_EXPRs. */
4708 && gimple_code (last) == GIMPLE_COND
4709 && !fp_predicate (last)
4710 && !ZERO_SSA_OPERANDS (last, SSA_OP_USE))
4711 need_assert |= find_conditional_asserts (bb, last);
4713 /* If BB's last statement is a switch statement involving integer
4714 operands, determine if we need to add ASSERT_EXPRs. */
4716 && gimple_code (last) == GIMPLE_SWITCH
4717 && !ZERO_SSA_OPERANDS (last, SSA_OP_USE))
4718 need_assert |= find_switch_asserts (bb, last);
4720 /* Traverse all the statements in BB marking used names and looking
4721 for statements that may infer assertions for their used operands. */
4722 for (si = gsi_start_bb (bb); !gsi_end_p (si); gsi_next (&si))
4728 stmt = gsi_stmt (si);
4730 if (is_gimple_debug (stmt))
4733 /* See if we can derive an assertion for any of STMT's operands. */
4734 FOR_EACH_SSA_TREE_OPERAND (op, stmt, i, SSA_OP_USE)
4737 enum tree_code comp_code;
4739 /* Mark OP in our live bitmap. */
4740 SET_BIT (live, SSA_NAME_VERSION (op));
4742 /* If OP is used in such a way that we can infer a value
4743 range for it, and we don't find a previous assertion for
4744 it, create a new assertion location node for OP. */
4745 if (infer_value_range (stmt, op, &comp_code, &value))
4747 /* If we are able to infer a nonzero value range for OP,
4748 then walk backwards through the use-def chain to see if OP
4749 was set via a typecast.
4751 If so, then we can also infer a nonzero value range
4752 for the operand of the NOP_EXPR. */
4753 if (comp_code == NE_EXPR && integer_zerop (value))
4756 gimple def_stmt = SSA_NAME_DEF_STMT (t);
4758 while (is_gimple_assign (def_stmt)
4759 && gimple_assign_rhs_code (def_stmt) == NOP_EXPR
4761 (gimple_assign_rhs1 (def_stmt)) == SSA_NAME
4763 (TREE_TYPE (gimple_assign_rhs1 (def_stmt))))
4765 t = gimple_assign_rhs1 (def_stmt);
4766 def_stmt = SSA_NAME_DEF_STMT (t);
4768 /* Note we want to register the assert for the
4769 operand of the NOP_EXPR after SI, not after the
4771 if (! has_single_use (t))
4773 register_new_assert_for (t, t, comp_code, value,
4780 /* If OP is used only once, namely in this STMT, don't
4781 bother creating an ASSERT_EXPR for it. Such an
4782 ASSERT_EXPR would do nothing but increase compile time. */
4783 if (!has_single_use (op))
4785 register_new_assert_for (op, op, comp_code, value,
4793 /* Traverse all PHI nodes in BB marking used operands. */
4794 for (si = gsi_start_phis (bb); !gsi_end_p(si); gsi_next (&si))
4796 use_operand_p arg_p;
4798 phi = gsi_stmt (si);
4800 FOR_EACH_PHI_ARG (arg_p, phi, i, SSA_OP_USE)
4802 tree arg = USE_FROM_PTR (arg_p);
4803 if (TREE_CODE (arg) == SSA_NAME)
4804 SET_BIT (live, SSA_NAME_VERSION (arg));
4811 /* Do an RPO walk over the function computing SSA name liveness
4812 on-the-fly and deciding on assert expressions to insert.
4813 Returns true if there are assert expressions to be inserted. */
4816 find_assert_locations (void)
4818 int *rpo = XCNEWVEC (int, last_basic_block + NUM_FIXED_BLOCKS);
4819 int *bb_rpo = XCNEWVEC (int, last_basic_block + NUM_FIXED_BLOCKS);
4820 int *last_rpo = XCNEWVEC (int, last_basic_block + NUM_FIXED_BLOCKS);
4824 live = XCNEWVEC (sbitmap, last_basic_block + NUM_FIXED_BLOCKS);
4825 rpo_cnt = pre_and_rev_post_order_compute (NULL, rpo, false);
4826 for (i = 0; i < rpo_cnt; ++i)
4829 need_asserts = false;
4830 for (i = rpo_cnt-1; i >= 0; --i)
4832 basic_block bb = BASIC_BLOCK (rpo[i]);
4838 live[rpo[i]] = sbitmap_alloc (num_ssa_names);
4839 sbitmap_zero (live[rpo[i]]);
4842 /* Process BB and update the live information with uses in
4844 need_asserts |= find_assert_locations_1 (bb, live[rpo[i]]);
4846 /* Merge liveness into the predecessor blocks and free it. */
4847 if (!sbitmap_empty_p (live[rpo[i]]))
4850 FOR_EACH_EDGE (e, ei, bb->preds)
4852 int pred = e->src->index;
4853 if (e->flags & EDGE_DFS_BACK)
4858 live[pred] = sbitmap_alloc (num_ssa_names);
4859 sbitmap_zero (live[pred]);
4861 sbitmap_a_or_b (live[pred], live[pred], live[rpo[i]]);
4863 if (bb_rpo[pred] < pred_rpo)
4864 pred_rpo = bb_rpo[pred];
4867 /* Record the RPO number of the last visited block that needs
4868 live information from this block. */
4869 last_rpo[rpo[i]] = pred_rpo;
4873 sbitmap_free (live[rpo[i]]);
4874 live[rpo[i]] = NULL;
4877 /* We can free all successors live bitmaps if all their
4878 predecessors have been visited already. */
4879 FOR_EACH_EDGE (e, ei, bb->succs)
4880 if (last_rpo[e->dest->index] == i
4881 && live[e->dest->index])
4883 sbitmap_free (live[e->dest->index]);
4884 live[e->dest->index] = NULL;
4889 XDELETEVEC (bb_rpo);
4890 XDELETEVEC (last_rpo);
4891 for (i = 0; i < last_basic_block + NUM_FIXED_BLOCKS; ++i)
4893 sbitmap_free (live[i]);
4896 return need_asserts;
4899 /* Create an ASSERT_EXPR for NAME and insert it in the location
4900 indicated by LOC. Return true if we made any edge insertions. */
4903 process_assert_insertions_for (tree name, assert_locus_t loc)
4905 /* Build the comparison expression NAME_i COMP_CODE VAL. */
4912 /* If we have X <=> X do not insert an assert expr for that. */
4913 if (loc->expr == loc->val)
4916 cond = build2 (loc->comp_code, boolean_type_node, loc->expr, loc->val);
4917 assert_stmt = build_assert_expr_for (cond, name);
4920 /* We have been asked to insert the assertion on an edge. This
4921 is used only by COND_EXPR and SWITCH_EXPR assertions. */
4922 #if defined ENABLE_CHECKING
4923 gcc_assert (gimple_code (gsi_stmt (loc->si)) == GIMPLE_COND
4924 || gimple_code (gsi_stmt (loc->si)) == GIMPLE_SWITCH);
4927 gsi_insert_on_edge (loc->e, assert_stmt);
4931 /* Otherwise, we can insert right after LOC->SI iff the
4932 statement must not be the last statement in the block. */
4933 stmt = gsi_stmt (loc->si);
4934 if (!stmt_ends_bb_p (stmt))
4936 gsi_insert_after (&loc->si, assert_stmt, GSI_SAME_STMT);
4940 /* If STMT must be the last statement in BB, we can only insert new
4941 assertions on the non-abnormal edge out of BB. Note that since
4942 STMT is not control flow, there may only be one non-abnormal edge
4944 FOR_EACH_EDGE (e, ei, loc->bb->succs)
4945 if (!(e->flags & EDGE_ABNORMAL))
4947 gsi_insert_on_edge (e, assert_stmt);
4955 /* Process all the insertions registered for every name N_i registered
4956 in NEED_ASSERT_FOR. The list of assertions to be inserted are
4957 found in ASSERTS_FOR[i]. */
4960 process_assert_insertions (void)
4964 bool update_edges_p = false;
4965 int num_asserts = 0;
4967 if (dump_file && (dump_flags & TDF_DETAILS))
4968 dump_all_asserts (dump_file);
4970 EXECUTE_IF_SET_IN_BITMAP (need_assert_for, 0, i, bi)
4972 assert_locus_t loc = asserts_for[i];
4977 assert_locus_t next = loc->next;
4978 update_edges_p |= process_assert_insertions_for (ssa_name (i), loc);
4986 gsi_commit_edge_inserts ();
4988 statistics_counter_event (cfun, "Number of ASSERT_EXPR expressions inserted",
4993 /* Traverse the flowgraph looking for conditional jumps to insert range
4994 expressions. These range expressions are meant to provide information
4995 to optimizations that need to reason in terms of value ranges. They
4996 will not be expanded into RTL. For instance, given:
5005 this pass will transform the code into:
5011 x = ASSERT_EXPR <x, x < y>
5016 y = ASSERT_EXPR <y, x <= y>
5020 The idea is that once copy and constant propagation have run, other
5021 optimizations will be able to determine what ranges of values can 'x'
5022 take in different paths of the code, simply by checking the reaching
5023 definition of 'x'. */
5026 insert_range_assertions (void)
5028 need_assert_for = BITMAP_ALLOC (NULL);
5029 asserts_for = XCNEWVEC (assert_locus_t, num_ssa_names);
5031 calculate_dominance_info (CDI_DOMINATORS);
5033 if (find_assert_locations ())
5035 process_assert_insertions ();
5036 update_ssa (TODO_update_ssa_no_phi);
5039 if (dump_file && (dump_flags & TDF_DETAILS))
5041 fprintf (dump_file, "\nSSA form after inserting ASSERT_EXPRs\n");
5042 dump_function_to_file (current_function_decl, dump_file, dump_flags);
5046 BITMAP_FREE (need_assert_for);
5049 /* Checks one ARRAY_REF in REF, located at LOCUS. Ignores flexible arrays
5050 and "struct" hacks. If VRP can determine that the
5051 array subscript is a constant, check if it is outside valid
5052 range. If the array subscript is a RANGE, warn if it is
5053 non-overlapping with valid range.
5054 IGNORE_OFF_BY_ONE is true if the ARRAY_REF is inside a ADDR_EXPR. */
5057 check_array_ref (location_t location, tree ref, bool ignore_off_by_one)
5059 value_range_t* vr = NULL;
5060 tree low_sub, up_sub;
5061 tree low_bound, up_bound, up_bound_p1;
5064 if (TREE_NO_WARNING (ref))
5067 low_sub = up_sub = TREE_OPERAND (ref, 1);
5068 up_bound = array_ref_up_bound (ref);
5070 /* Can not check flexible arrays. */
5072 || TREE_CODE (up_bound) != INTEGER_CST)
5075 /* Accesses to trailing arrays via pointers may access storage
5076 beyond the types array bounds. */
5077 base = get_base_address (ref);
5079 && INDIRECT_REF_P (base))
5081 tree cref, next = NULL_TREE;
5083 if (TREE_CODE (TREE_OPERAND (ref, 0)) != COMPONENT_REF)
5086 cref = TREE_OPERAND (ref, 0);
5087 if (TREE_CODE (TREE_TYPE (TREE_OPERAND (cref, 0))) == RECORD_TYPE)
5088 for (next = TREE_CHAIN (TREE_OPERAND (cref, 1));
5089 next && TREE_CODE (next) != FIELD_DECL;
5090 next = TREE_CHAIN (next))
5093 /* If this is the last field in a struct type or a field in a
5094 union type do not warn. */
5099 low_bound = array_ref_low_bound (ref);
5100 up_bound_p1 = int_const_binop (PLUS_EXPR, up_bound, integer_one_node, 0);
5102 if (TREE_CODE (low_sub) == SSA_NAME)
5104 vr = get_value_range (low_sub);
5105 if (vr->type == VR_RANGE || vr->type == VR_ANTI_RANGE)
5107 low_sub = vr->type == VR_RANGE ? vr->max : vr->min;
5108 up_sub = vr->type == VR_RANGE ? vr->min : vr->max;
5112 if (vr && vr->type == VR_ANTI_RANGE)
5114 if (TREE_CODE (up_sub) == INTEGER_CST
5115 && tree_int_cst_lt (up_bound, up_sub)
5116 && TREE_CODE (low_sub) == INTEGER_CST
5117 && tree_int_cst_lt (low_sub, low_bound))
5119 warning_at (location, OPT_Warray_bounds,
5120 "array subscript is outside array bounds");
5121 TREE_NO_WARNING (ref) = 1;
5124 else if (TREE_CODE (up_sub) == INTEGER_CST
5125 && (ignore_off_by_one
5126 ? (tree_int_cst_lt (up_bound, up_sub)
5127 && !tree_int_cst_equal (up_bound_p1, up_sub))
5128 : (tree_int_cst_lt (up_bound, up_sub)
5129 || tree_int_cst_equal (up_bound_p1, up_sub))))
5131 warning_at (location, OPT_Warray_bounds,
5132 "array subscript is above array bounds");
5133 TREE_NO_WARNING (ref) = 1;
5135 else if (TREE_CODE (low_sub) == INTEGER_CST
5136 && tree_int_cst_lt (low_sub, low_bound))
5138 warning_at (location, OPT_Warray_bounds,
5139 "array subscript is below array bounds");
5140 TREE_NO_WARNING (ref) = 1;
5144 /* Searches if the expr T, located at LOCATION computes
5145 address of an ARRAY_REF, and call check_array_ref on it. */
5148 search_for_addr_array (tree t, location_t location)
5150 while (TREE_CODE (t) == SSA_NAME)
5152 gimple g = SSA_NAME_DEF_STMT (t);
5154 if (gimple_code (g) != GIMPLE_ASSIGN)
5157 if (get_gimple_rhs_class (gimple_assign_rhs_code (g))
5158 != GIMPLE_SINGLE_RHS)
5161 t = gimple_assign_rhs1 (g);
5165 /* We are only interested in addresses of ARRAY_REF's. */
5166 if (TREE_CODE (t) != ADDR_EXPR)
5169 /* Check each ARRAY_REFs in the reference chain. */
5172 if (TREE_CODE (t) == ARRAY_REF)
5173 check_array_ref (location, t, true /*ignore_off_by_one*/);
5175 t = TREE_OPERAND (t, 0);
5177 while (handled_component_p (t));
5180 /* walk_tree() callback that checks if *TP is
5181 an ARRAY_REF inside an ADDR_EXPR (in which an array
5182 subscript one outside the valid range is allowed). Call
5183 check_array_ref for each ARRAY_REF found. The location is
5187 check_array_bounds (tree *tp, int *walk_subtree, void *data)
5190 struct walk_stmt_info *wi = (struct walk_stmt_info *) data;
5191 location_t location;
5193 if (EXPR_HAS_LOCATION (t))
5194 location = EXPR_LOCATION (t);
5197 location_t *locp = (location_t *) wi->info;
5201 *walk_subtree = TRUE;
5203 if (TREE_CODE (t) == ARRAY_REF)
5204 check_array_ref (location, t, false /*ignore_off_by_one*/);
5206 if (TREE_CODE (t) == INDIRECT_REF
5207 || (TREE_CODE (t) == RETURN_EXPR && TREE_OPERAND (t, 0)))
5208 search_for_addr_array (TREE_OPERAND (t, 0), location);
5210 if (TREE_CODE (t) == ADDR_EXPR)
5211 *walk_subtree = FALSE;
5216 /* Walk over all statements of all reachable BBs and call check_array_bounds
5220 check_all_array_refs (void)
5223 gimple_stmt_iterator si;
5229 bool executable = false;
5231 /* Skip blocks that were found to be unreachable. */
5232 FOR_EACH_EDGE (e, ei, bb->preds)
5233 executable |= !!(e->flags & EDGE_EXECUTABLE);
5237 for (si = gsi_start_bb (bb); !gsi_end_p (si); gsi_next (&si))
5239 gimple stmt = gsi_stmt (si);
5240 struct walk_stmt_info wi;
5241 if (!gimple_has_location (stmt))
5244 if (is_gimple_call (stmt))
5247 size_t n = gimple_call_num_args (stmt);
5248 for (i = 0; i < n; i++)
5250 tree arg = gimple_call_arg (stmt, i);
5251 search_for_addr_array (arg, gimple_location (stmt));
5256 memset (&wi, 0, sizeof (wi));
5257 wi.info = CONST_CAST (void *, (const void *)
5258 gimple_location_ptr (stmt));
5260 walk_gimple_op (gsi_stmt (si),
5268 /* Convert range assertion expressions into the implied copies and
5269 copy propagate away the copies. Doing the trivial copy propagation
5270 here avoids the need to run the full copy propagation pass after
5273 FIXME, this will eventually lead to copy propagation removing the
5274 names that had useful range information attached to them. For
5275 instance, if we had the assertion N_i = ASSERT_EXPR <N_j, N_j > 3>,
5276 then N_i will have the range [3, +INF].
5278 However, by converting the assertion into the implied copy
5279 operation N_i = N_j, we will then copy-propagate N_j into the uses
5280 of N_i and lose the range information. We may want to hold on to
5281 ASSERT_EXPRs a little while longer as the ranges could be used in
5282 things like jump threading.
5284 The problem with keeping ASSERT_EXPRs around is that passes after
5285 VRP need to handle them appropriately.
5287 Another approach would be to make the range information a first
5288 class property of the SSA_NAME so that it can be queried from
5289 any pass. This is made somewhat more complex by the need for
5290 multiple ranges to be associated with one SSA_NAME. */
5293 remove_range_assertions (void)
5296 gimple_stmt_iterator si;
5298 /* Note that the BSI iterator bump happens at the bottom of the
5299 loop and no bump is necessary if we're removing the statement
5300 referenced by the current BSI. */
5302 for (si = gsi_start_bb (bb); !gsi_end_p (si);)
5304 gimple stmt = gsi_stmt (si);
5307 if (is_gimple_assign (stmt)
5308 && gimple_assign_rhs_code (stmt) == ASSERT_EXPR)
5310 tree rhs = gimple_assign_rhs1 (stmt);
5312 tree cond = fold (ASSERT_EXPR_COND (rhs));
5313 use_operand_p use_p;
5314 imm_use_iterator iter;
5316 gcc_assert (cond != boolean_false_node);
5318 /* Propagate the RHS into every use of the LHS. */
5319 var = ASSERT_EXPR_VAR (rhs);
5320 FOR_EACH_IMM_USE_STMT (use_stmt, iter,
5321 gimple_assign_lhs (stmt))
5322 FOR_EACH_IMM_USE_ON_STMT (use_p, iter)
5324 SET_USE (use_p, var);
5325 gcc_assert (TREE_CODE (var) == SSA_NAME);
5328 /* And finally, remove the copy, it is not needed. */
5329 gsi_remove (&si, true);
5330 release_defs (stmt);
5338 /* Return true if STMT is interesting for VRP. */
5341 stmt_interesting_for_vrp (gimple stmt)
5343 if (gimple_code (stmt) == GIMPLE_PHI
5344 && is_gimple_reg (gimple_phi_result (stmt))
5345 && (INTEGRAL_TYPE_P (TREE_TYPE (gimple_phi_result (stmt)))
5346 || POINTER_TYPE_P (TREE_TYPE (gimple_phi_result (stmt)))))
5348 else if (is_gimple_assign (stmt) || is_gimple_call (stmt))
5350 tree lhs = gimple_get_lhs (stmt);
5352 /* In general, assignments with virtual operands are not useful
5353 for deriving ranges, with the obvious exception of calls to
5354 builtin functions. */
5355 if (lhs && TREE_CODE (lhs) == SSA_NAME
5356 && (INTEGRAL_TYPE_P (TREE_TYPE (lhs))
5357 || POINTER_TYPE_P (TREE_TYPE (lhs)))
5358 && ((is_gimple_call (stmt)
5359 && gimple_call_fndecl (stmt) != NULL_TREE
5360 && DECL_IS_BUILTIN (gimple_call_fndecl (stmt)))
5361 || !gimple_vuse (stmt)))
5364 else if (gimple_code (stmt) == GIMPLE_COND
5365 || gimple_code (stmt) == GIMPLE_SWITCH)
5372 /* Initialize local data structures for VRP. */
5375 vrp_initialize (void)
5379 vr_value = XCNEWVEC (value_range_t *, num_ssa_names);
5380 vr_phi_edge_counts = XCNEWVEC (int, num_ssa_names);
5384 gimple_stmt_iterator si;
5386 for (si = gsi_start_phis (bb); !gsi_end_p (si); gsi_next (&si))
5388 gimple phi = gsi_stmt (si);
5389 if (!stmt_interesting_for_vrp (phi))
5391 tree lhs = PHI_RESULT (phi);
5392 set_value_range_to_varying (get_value_range (lhs));
5393 prop_set_simulate_again (phi, false);
5396 prop_set_simulate_again (phi, true);
5399 for (si = gsi_start_bb (bb); !gsi_end_p (si); gsi_next (&si))
5401 gimple stmt = gsi_stmt (si);
5403 /* If the statement is a control insn, then we do not
5404 want to avoid simulating the statement once. Failure
5405 to do so means that those edges will never get added. */
5406 if (stmt_ends_bb_p (stmt))
5407 prop_set_simulate_again (stmt, true);
5408 else if (!stmt_interesting_for_vrp (stmt))
5412 FOR_EACH_SSA_TREE_OPERAND (def, stmt, i, SSA_OP_DEF)
5413 set_value_range_to_varying (get_value_range (def));
5414 prop_set_simulate_again (stmt, false);
5417 prop_set_simulate_again (stmt, true);
5423 /* Visit assignment STMT. If it produces an interesting range, record
5424 the SSA name in *OUTPUT_P. */
5426 static enum ssa_prop_result
5427 vrp_visit_assignment_or_call (gimple stmt, tree *output_p)
5431 enum gimple_code code = gimple_code (stmt);
5432 lhs = gimple_get_lhs (stmt);
5434 /* We only keep track of ranges in integral and pointer types. */
5435 if (TREE_CODE (lhs) == SSA_NAME
5436 && ((INTEGRAL_TYPE_P (TREE_TYPE (lhs))
5437 /* It is valid to have NULL MIN/MAX values on a type. See
5438 build_range_type. */
5439 && TYPE_MIN_VALUE (TREE_TYPE (lhs))
5440 && TYPE_MAX_VALUE (TREE_TYPE (lhs)))
5441 || POINTER_TYPE_P (TREE_TYPE (lhs))))
5443 value_range_t new_vr = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
5445 if (code == GIMPLE_CALL)
5446 extract_range_basic (&new_vr, stmt);
5448 extract_range_from_assignment (&new_vr, stmt);
5450 if (update_value_range (lhs, &new_vr))
5454 if (dump_file && (dump_flags & TDF_DETAILS))
5456 fprintf (dump_file, "Found new range for ");
5457 print_generic_expr (dump_file, lhs, 0);
5458 fprintf (dump_file, ": ");
5459 dump_value_range (dump_file, &new_vr);
5460 fprintf (dump_file, "\n\n");
5463 if (new_vr.type == VR_VARYING)
5464 return SSA_PROP_VARYING;
5466 return SSA_PROP_INTERESTING;
5469 return SSA_PROP_NOT_INTERESTING;
5472 /* Every other statement produces no useful ranges. */
5473 FOR_EACH_SSA_TREE_OPERAND (def, stmt, iter, SSA_OP_DEF)
5474 set_value_range_to_varying (get_value_range (def));
5476 return SSA_PROP_VARYING;
5479 /* Helper that gets the value range of the SSA_NAME with version I
5480 or a symbolic range containing the SSA_NAME only if the value range
5481 is varying or undefined. */
5483 static inline value_range_t
5484 get_vr_for_comparison (int i)
5486 value_range_t vr = *(vr_value[i]);
5488 /* If name N_i does not have a valid range, use N_i as its own
5489 range. This allows us to compare against names that may
5490 have N_i in their ranges. */
5491 if (vr.type == VR_VARYING || vr.type == VR_UNDEFINED)
5494 vr.min = ssa_name (i);
5495 vr.max = ssa_name (i);
5501 /* Compare all the value ranges for names equivalent to VAR with VAL
5502 using comparison code COMP. Return the same value returned by
5503 compare_range_with_value, including the setting of
5504 *STRICT_OVERFLOW_P. */
5507 compare_name_with_value (enum tree_code comp, tree var, tree val,
5508 bool *strict_overflow_p)
5514 int used_strict_overflow;
5516 value_range_t equiv_vr;
5518 /* Get the set of equivalences for VAR. */
5519 e = get_value_range (var)->equiv;
5521 /* Start at -1. Set it to 0 if we do a comparison without relying
5522 on overflow, or 1 if all comparisons rely on overflow. */
5523 used_strict_overflow = -1;
5525 /* Compare vars' value range with val. */
5526 equiv_vr = get_vr_for_comparison (SSA_NAME_VERSION (var));
5528 retval = compare_range_with_value (comp, &equiv_vr, val, &sop);
5530 used_strict_overflow = sop ? 1 : 0;
5532 /* If the equiv set is empty we have done all work we need to do. */
5536 && used_strict_overflow > 0)
5537 *strict_overflow_p = true;
5541 EXECUTE_IF_SET_IN_BITMAP (e, 0, i, bi)
5543 equiv_vr = get_vr_for_comparison (i);
5545 t = compare_range_with_value (comp, &equiv_vr, val, &sop);
5548 /* If we get different answers from different members
5549 of the equivalence set this check must be in a dead
5550 code region. Folding it to a trap representation
5551 would be correct here. For now just return don't-know. */
5561 used_strict_overflow = 0;
5562 else if (used_strict_overflow < 0)
5563 used_strict_overflow = 1;
5568 && used_strict_overflow > 0)
5569 *strict_overflow_p = true;
5575 /* Given a comparison code COMP and names N1 and N2, compare all the
5576 ranges equivalent to N1 against all the ranges equivalent to N2
5577 to determine the value of N1 COMP N2. Return the same value
5578 returned by compare_ranges. Set *STRICT_OVERFLOW_P to indicate
5579 whether we relied on an overflow infinity in the comparison. */
5583 compare_names (enum tree_code comp, tree n1, tree n2,
5584 bool *strict_overflow_p)
5588 bitmap_iterator bi1, bi2;
5590 int used_strict_overflow;
5591 static bitmap_obstack *s_obstack = NULL;
5592 static bitmap s_e1 = NULL, s_e2 = NULL;
5594 /* Compare the ranges of every name equivalent to N1 against the
5595 ranges of every name equivalent to N2. */
5596 e1 = get_value_range (n1)->equiv;
5597 e2 = get_value_range (n2)->equiv;
5599 /* Use the fake bitmaps if e1 or e2 are not available. */
5600 if (s_obstack == NULL)
5602 s_obstack = XNEW (bitmap_obstack);
5603 bitmap_obstack_initialize (s_obstack);
5604 s_e1 = BITMAP_ALLOC (s_obstack);
5605 s_e2 = BITMAP_ALLOC (s_obstack);
5612 /* Add N1 and N2 to their own set of equivalences to avoid
5613 duplicating the body of the loop just to check N1 and N2
5615 bitmap_set_bit (e1, SSA_NAME_VERSION (n1));
5616 bitmap_set_bit (e2, SSA_NAME_VERSION (n2));
5618 /* If the equivalence sets have a common intersection, then the two
5619 names can be compared without checking their ranges. */
5620 if (bitmap_intersect_p (e1, e2))
5622 bitmap_clear_bit (e1, SSA_NAME_VERSION (n1));
5623 bitmap_clear_bit (e2, SSA_NAME_VERSION (n2));
5625 return (comp == EQ_EXPR || comp == GE_EXPR || comp == LE_EXPR)
5627 : boolean_false_node;
5630 /* Start at -1. Set it to 0 if we do a comparison without relying
5631 on overflow, or 1 if all comparisons rely on overflow. */
5632 used_strict_overflow = -1;
5634 /* Otherwise, compare all the equivalent ranges. First, add N1 and
5635 N2 to their own set of equivalences to avoid duplicating the body
5636 of the loop just to check N1 and N2 ranges. */
5637 EXECUTE_IF_SET_IN_BITMAP (e1, 0, i1, bi1)
5639 value_range_t vr1 = get_vr_for_comparison (i1);
5641 t = retval = NULL_TREE;
5642 EXECUTE_IF_SET_IN_BITMAP (e2, 0, i2, bi2)
5646 value_range_t vr2 = get_vr_for_comparison (i2);
5648 t = compare_ranges (comp, &vr1, &vr2, &sop);
5651 /* If we get different answers from different members
5652 of the equivalence set this check must be in a dead
5653 code region. Folding it to a trap representation
5654 would be correct here. For now just return don't-know. */
5658 bitmap_clear_bit (e1, SSA_NAME_VERSION (n1));
5659 bitmap_clear_bit (e2, SSA_NAME_VERSION (n2));
5665 used_strict_overflow = 0;
5666 else if (used_strict_overflow < 0)
5667 used_strict_overflow = 1;
5673 bitmap_clear_bit (e1, SSA_NAME_VERSION (n1));
5674 bitmap_clear_bit (e2, SSA_NAME_VERSION (n2));
5675 if (used_strict_overflow > 0)
5676 *strict_overflow_p = true;
5681 /* None of the equivalent ranges are useful in computing this
5683 bitmap_clear_bit (e1, SSA_NAME_VERSION (n1));
5684 bitmap_clear_bit (e2, SSA_NAME_VERSION (n2));
5688 /* Helper function for vrp_evaluate_conditional_warnv. */
5691 vrp_evaluate_conditional_warnv_with_ops_using_ranges (enum tree_code code,
5693 bool * strict_overflow_p)
5695 value_range_t *vr0, *vr1;
5697 vr0 = (TREE_CODE (op0) == SSA_NAME) ? get_value_range (op0) : NULL;
5698 vr1 = (TREE_CODE (op1) == SSA_NAME) ? get_value_range (op1) : NULL;
5701 return compare_ranges (code, vr0, vr1, strict_overflow_p);
5702 else if (vr0 && vr1 == NULL)
5703 return compare_range_with_value (code, vr0, op1, strict_overflow_p);
5704 else if (vr0 == NULL && vr1)
5705 return (compare_range_with_value
5706 (swap_tree_comparison (code), vr1, op0, strict_overflow_p));
5710 /* Helper function for vrp_evaluate_conditional_warnv. */
5713 vrp_evaluate_conditional_warnv_with_ops (enum tree_code code, tree op0,
5714 tree op1, bool use_equiv_p,
5715 bool *strict_overflow_p, bool *only_ranges)
5719 *only_ranges = true;
5721 /* We only deal with integral and pointer types. */
5722 if (!INTEGRAL_TYPE_P (TREE_TYPE (op0))
5723 && !POINTER_TYPE_P (TREE_TYPE (op0)))
5729 && (ret = vrp_evaluate_conditional_warnv_with_ops_using_ranges
5730 (code, op0, op1, strict_overflow_p)))
5732 *only_ranges = false;
5733 if (TREE_CODE (op0) == SSA_NAME && TREE_CODE (op1) == SSA_NAME)
5734 return compare_names (code, op0, op1, strict_overflow_p);
5735 else if (TREE_CODE (op0) == SSA_NAME)
5736 return compare_name_with_value (code, op0, op1, strict_overflow_p);
5737 else if (TREE_CODE (op1) == SSA_NAME)
5738 return (compare_name_with_value
5739 (swap_tree_comparison (code), op1, op0, strict_overflow_p));
5742 return vrp_evaluate_conditional_warnv_with_ops_using_ranges (code, op0, op1,
5747 /* Given (CODE OP0 OP1) within STMT, try to simplify it based on value range
5748 information. Return NULL if the conditional can not be evaluated.
5749 The ranges of all the names equivalent with the operands in COND
5750 will be used when trying to compute the value. If the result is
5751 based on undefined signed overflow, issue a warning if
5755 vrp_evaluate_conditional (enum tree_code code, tree op0, tree op1, gimple stmt)
5761 /* Some passes and foldings leak constants with overflow flag set
5762 into the IL. Avoid doing wrong things with these and bail out. */
5763 if ((TREE_CODE (op0) == INTEGER_CST
5764 && TREE_OVERFLOW (op0))
5765 || (TREE_CODE (op1) == INTEGER_CST
5766 && TREE_OVERFLOW (op1)))
5770 ret = vrp_evaluate_conditional_warnv_with_ops (code, op0, op1, true, &sop,
5775 enum warn_strict_overflow_code wc;
5776 const char* warnmsg;
5778 if (is_gimple_min_invariant (ret))
5780 wc = WARN_STRICT_OVERFLOW_CONDITIONAL;
5781 warnmsg = G_("assuming signed overflow does not occur when "
5782 "simplifying conditional to constant");
5786 wc = WARN_STRICT_OVERFLOW_COMPARISON;
5787 warnmsg = G_("assuming signed overflow does not occur when "
5788 "simplifying conditional");
5791 if (issue_strict_overflow_warning (wc))
5793 location_t location;
5795 if (!gimple_has_location (stmt))
5796 location = input_location;
5798 location = gimple_location (stmt);
5799 warning_at (location, OPT_Wstrict_overflow, "%s", warnmsg);
5803 if (warn_type_limits
5804 && ret && only_ranges
5805 && TREE_CODE_CLASS (code) == tcc_comparison
5806 && TREE_CODE (op0) == SSA_NAME)
5808 /* If the comparison is being folded and the operand on the LHS
5809 is being compared against a constant value that is outside of
5810 the natural range of OP0's type, then the predicate will
5811 always fold regardless of the value of OP0. If -Wtype-limits
5812 was specified, emit a warning. */
5813 tree type = TREE_TYPE (op0);
5814 value_range_t *vr0 = get_value_range (op0);
5816 if (vr0->type != VR_VARYING
5817 && INTEGRAL_TYPE_P (type)
5818 && vrp_val_is_min (vr0->min)
5819 && vrp_val_is_max (vr0->max)
5820 && is_gimple_min_invariant (op1))
5822 location_t location;
5824 if (!gimple_has_location (stmt))
5825 location = input_location;
5827 location = gimple_location (stmt);
5829 warning_at (location, OPT_Wtype_limits,
5831 ? G_("comparison always false "
5832 "due to limited range of data type")
5833 : G_("comparison always true "
5834 "due to limited range of data type"));
5842 /* Visit conditional statement STMT. If we can determine which edge
5843 will be taken out of STMT's basic block, record it in
5844 *TAKEN_EDGE_P and return SSA_PROP_INTERESTING. Otherwise, return
5845 SSA_PROP_VARYING. */
5847 static enum ssa_prop_result
5848 vrp_visit_cond_stmt (gimple stmt, edge *taken_edge_p)
5853 *taken_edge_p = NULL;
5855 if (dump_file && (dump_flags & TDF_DETAILS))
5860 fprintf (dump_file, "\nVisiting conditional with predicate: ");
5861 print_gimple_stmt (dump_file, stmt, 0, 0);
5862 fprintf (dump_file, "\nWith known ranges\n");
5864 FOR_EACH_SSA_TREE_OPERAND (use, stmt, i, SSA_OP_USE)
5866 fprintf (dump_file, "\t");
5867 print_generic_expr (dump_file, use, 0);
5868 fprintf (dump_file, ": ");
5869 dump_value_range (dump_file, vr_value[SSA_NAME_VERSION (use)]);
5872 fprintf (dump_file, "\n");
5875 /* Compute the value of the predicate COND by checking the known
5876 ranges of each of its operands.
5878 Note that we cannot evaluate all the equivalent ranges here
5879 because those ranges may not yet be final and with the current
5880 propagation strategy, we cannot determine when the value ranges
5881 of the names in the equivalence set have changed.
5883 For instance, given the following code fragment
5887 i_14 = ASSERT_EXPR <i_5, i_5 != 0>
5891 Assume that on the first visit to i_14, i_5 has the temporary
5892 range [8, 8] because the second argument to the PHI function is
5893 not yet executable. We derive the range ~[0, 0] for i_14 and the
5894 equivalence set { i_5 }. So, when we visit 'if (i_14 == 1)' for
5895 the first time, since i_14 is equivalent to the range [8, 8], we
5896 determine that the predicate is always false.
5898 On the next round of propagation, i_13 is determined to be
5899 VARYING, which causes i_5 to drop down to VARYING. So, another
5900 visit to i_14 is scheduled. In this second visit, we compute the
5901 exact same range and equivalence set for i_14, namely ~[0, 0] and
5902 { i_5 }. But we did not have the previous range for i_5
5903 registered, so vrp_visit_assignment thinks that the range for
5904 i_14 has not changed. Therefore, the predicate 'if (i_14 == 1)'
5905 is not visited again, which stops propagation from visiting
5906 statements in the THEN clause of that if().
5908 To properly fix this we would need to keep the previous range
5909 value for the names in the equivalence set. This way we would've
5910 discovered that from one visit to the other i_5 changed from
5911 range [8, 8] to VR_VARYING.
5913 However, fixing this apparent limitation may not be worth the
5914 additional checking. Testing on several code bases (GCC, DLV,
5915 MICO, TRAMP3D and SPEC2000) showed that doing this results in
5916 4 more predicates folded in SPEC. */
5919 val = vrp_evaluate_conditional_warnv_with_ops (gimple_cond_code (stmt),
5920 gimple_cond_lhs (stmt),
5921 gimple_cond_rhs (stmt),
5926 *taken_edge_p = find_taken_edge (gimple_bb (stmt), val);
5929 if (dump_file && (dump_flags & TDF_DETAILS))
5931 "\nIgnoring predicate evaluation because "
5932 "it assumes that signed overflow is undefined");
5937 if (dump_file && (dump_flags & TDF_DETAILS))
5939 fprintf (dump_file, "\nPredicate evaluates to: ");
5940 if (val == NULL_TREE)
5941 fprintf (dump_file, "DON'T KNOW\n");
5943 print_generic_stmt (dump_file, val, 0);
5946 return (*taken_edge_p) ? SSA_PROP_INTERESTING : SSA_PROP_VARYING;
5949 /* Searches the case label vector VEC for the index *IDX of the CASE_LABEL
5950 that includes the value VAL. The search is restricted to the range
5951 [START_IDX, n - 1] where n is the size of VEC.
5953 If there is a CASE_LABEL for VAL, its index is placed in IDX and true is
5956 If there is no CASE_LABEL for VAL and there is one that is larger than VAL,
5957 it is placed in IDX and false is returned.
5959 If VAL is larger than any CASE_LABEL, n is placed on IDX and false is
5963 find_case_label_index (gimple stmt, size_t start_idx, tree val, size_t *idx)
5965 size_t n = gimple_switch_num_labels (stmt);
5968 /* Find case label for minimum of the value range or the next one.
5969 At each iteration we are searching in [low, high - 1]. */
5971 for (low = start_idx, high = n; high != low; )
5975 /* Note that i != high, so we never ask for n. */
5976 size_t i = (high + low) / 2;
5977 t = gimple_switch_label (stmt, i);
5979 /* Cache the result of comparing CASE_LOW and val. */
5980 cmp = tree_int_cst_compare (CASE_LOW (t), val);
5984 /* Ranges cannot be empty. */
5993 if (CASE_HIGH (t) != NULL
5994 && tree_int_cst_compare (CASE_HIGH (t), val) >= 0)
6006 /* Searches the case label vector VEC for the range of CASE_LABELs that is used
6007 for values between MIN and MAX. The first index is placed in MIN_IDX. The
6008 last index is placed in MAX_IDX. If the range of CASE_LABELs is empty
6009 then MAX_IDX < MIN_IDX.
6010 Returns true if the default label is not needed. */
6013 find_case_label_range (gimple stmt, tree min, tree max, size_t *min_idx,
6017 bool min_take_default = !find_case_label_index (stmt, 1, min, &i);
6018 bool max_take_default = !find_case_label_index (stmt, i, max, &j);
6022 && max_take_default)
6024 /* Only the default case label reached.
6025 Return an empty range. */
6032 bool take_default = min_take_default || max_take_default;
6036 if (max_take_default)
6039 /* If the case label range is continuous, we do not need
6040 the default case label. Verify that. */
6041 high = CASE_LOW (gimple_switch_label (stmt, i));
6042 if (CASE_HIGH (gimple_switch_label (stmt, i)))
6043 high = CASE_HIGH (gimple_switch_label (stmt, i));
6044 for (k = i + 1; k <= j; ++k)
6046 low = CASE_LOW (gimple_switch_label (stmt, k));
6047 if (!integer_onep (int_const_binop (MINUS_EXPR, low, high, 0)))
6049 take_default = true;
6053 if (CASE_HIGH (gimple_switch_label (stmt, k)))
6054 high = CASE_HIGH (gimple_switch_label (stmt, k));
6059 return !take_default;
6063 /* Visit switch statement STMT. If we can determine which edge
6064 will be taken out of STMT's basic block, record it in
6065 *TAKEN_EDGE_P and return SSA_PROP_INTERESTING. Otherwise, return
6066 SSA_PROP_VARYING. */
6068 static enum ssa_prop_result
6069 vrp_visit_switch_stmt (gimple stmt, edge *taken_edge_p)
6073 size_t i = 0, j = 0;
6076 *taken_edge_p = NULL;
6077 op = gimple_switch_index (stmt);
6078 if (TREE_CODE (op) != SSA_NAME)
6079 return SSA_PROP_VARYING;
6081 vr = get_value_range (op);
6082 if (dump_file && (dump_flags & TDF_DETAILS))
6084 fprintf (dump_file, "\nVisiting switch expression with operand ");
6085 print_generic_expr (dump_file, op, 0);
6086 fprintf (dump_file, " with known range ");
6087 dump_value_range (dump_file, vr);
6088 fprintf (dump_file, "\n");
6091 if (vr->type != VR_RANGE
6092 || symbolic_range_p (vr))
6093 return SSA_PROP_VARYING;
6095 /* Find the single edge that is taken from the switch expression. */
6096 take_default = !find_case_label_range (stmt, vr->min, vr->max, &i, &j);
6098 /* Check if the range spans no CASE_LABEL. If so, we only reach the default
6102 gcc_assert (take_default);
6103 val = gimple_switch_default_label (stmt);
6107 /* Check if labels with index i to j and maybe the default label
6108 are all reaching the same label. */
6110 val = gimple_switch_label (stmt, i);
6112 && CASE_LABEL (gimple_switch_default_label (stmt))
6113 != CASE_LABEL (val))
6115 if (dump_file && (dump_flags & TDF_DETAILS))
6116 fprintf (dump_file, " not a single destination for this "
6118 return SSA_PROP_VARYING;
6120 for (++i; i <= j; ++i)
6122 if (CASE_LABEL (gimple_switch_label (stmt, i)) != CASE_LABEL (val))
6124 if (dump_file && (dump_flags & TDF_DETAILS))
6125 fprintf (dump_file, " not a single destination for this "
6127 return SSA_PROP_VARYING;
6132 *taken_edge_p = find_edge (gimple_bb (stmt),
6133 label_to_block (CASE_LABEL (val)));
6135 if (dump_file && (dump_flags & TDF_DETAILS))
6137 fprintf (dump_file, " will take edge to ");
6138 print_generic_stmt (dump_file, CASE_LABEL (val), 0);
6141 return SSA_PROP_INTERESTING;
6145 /* Evaluate statement STMT. If the statement produces a useful range,
6146 return SSA_PROP_INTERESTING and record the SSA name with the
6147 interesting range into *OUTPUT_P.
6149 If STMT is a conditional branch and we can determine its truth
6150 value, the taken edge is recorded in *TAKEN_EDGE_P.
6152 If STMT produces a varying value, return SSA_PROP_VARYING. */
6154 static enum ssa_prop_result
6155 vrp_visit_stmt (gimple stmt, edge *taken_edge_p, tree *output_p)
6160 if (dump_file && (dump_flags & TDF_DETAILS))
6162 fprintf (dump_file, "\nVisiting statement:\n");
6163 print_gimple_stmt (dump_file, stmt, 0, dump_flags);
6164 fprintf (dump_file, "\n");
6167 if (!stmt_interesting_for_vrp (stmt))
6168 gcc_assert (stmt_ends_bb_p (stmt));
6169 else if (is_gimple_assign (stmt) || is_gimple_call (stmt))
6171 /* In general, assignments with virtual operands are not useful
6172 for deriving ranges, with the obvious exception of calls to
6173 builtin functions. */
6175 if ((is_gimple_call (stmt)
6176 && gimple_call_fndecl (stmt) != NULL_TREE
6177 && DECL_IS_BUILTIN (gimple_call_fndecl (stmt)))
6178 || !gimple_vuse (stmt))
6179 return vrp_visit_assignment_or_call (stmt, output_p);
6181 else if (gimple_code (stmt) == GIMPLE_COND)
6182 return vrp_visit_cond_stmt (stmt, taken_edge_p);
6183 else if (gimple_code (stmt) == GIMPLE_SWITCH)
6184 return vrp_visit_switch_stmt (stmt, taken_edge_p);
6186 /* All other statements produce nothing of interest for VRP, so mark
6187 their outputs varying and prevent further simulation. */
6188 FOR_EACH_SSA_TREE_OPERAND (def, stmt, iter, SSA_OP_DEF)
6189 set_value_range_to_varying (get_value_range (def));
6191 return SSA_PROP_VARYING;
6195 /* Meet operation for value ranges. Given two value ranges VR0 and
6196 VR1, store in VR0 a range that contains both VR0 and VR1. This
6197 may not be the smallest possible such range. */
6200 vrp_meet (value_range_t *vr0, value_range_t *vr1)
6202 if (vr0->type == VR_UNDEFINED)
6204 copy_value_range (vr0, vr1);
6208 if (vr1->type == VR_UNDEFINED)
6210 /* Nothing to do. VR0 already has the resulting range. */
6214 if (vr0->type == VR_VARYING)
6216 /* Nothing to do. VR0 already has the resulting range. */
6220 if (vr1->type == VR_VARYING)
6222 set_value_range_to_varying (vr0);
6226 if (vr0->type == VR_RANGE && vr1->type == VR_RANGE)
6231 /* Compute the convex hull of the ranges. The lower limit of
6232 the new range is the minimum of the two ranges. If they
6233 cannot be compared, then give up. */
6234 cmp = compare_values (vr0->min, vr1->min);
6235 if (cmp == 0 || cmp == 1)
6242 /* Similarly, the upper limit of the new range is the maximum
6243 of the two ranges. If they cannot be compared, then
6245 cmp = compare_values (vr0->max, vr1->max);
6246 if (cmp == 0 || cmp == -1)
6253 /* Check for useless ranges. */
6254 if (INTEGRAL_TYPE_P (TREE_TYPE (min))
6255 && ((vrp_val_is_min (min) || is_overflow_infinity (min))
6256 && (vrp_val_is_max (max) || is_overflow_infinity (max))))
6259 /* The resulting set of equivalences is the intersection of
6261 if (vr0->equiv && vr1->equiv && vr0->equiv != vr1->equiv)
6262 bitmap_and_into (vr0->equiv, vr1->equiv);
6263 else if (vr0->equiv && !vr1->equiv)
6264 bitmap_clear (vr0->equiv);
6266 set_value_range (vr0, vr0->type, min, max, vr0->equiv);
6268 else if (vr0->type == VR_ANTI_RANGE && vr1->type == VR_ANTI_RANGE)
6270 /* Two anti-ranges meet only if their complements intersect.
6271 Only handle the case of identical ranges. */
6272 if (compare_values (vr0->min, vr1->min) == 0
6273 && compare_values (vr0->max, vr1->max) == 0
6274 && compare_values (vr0->min, vr0->max) == 0)
6276 /* The resulting set of equivalences is the intersection of
6278 if (vr0->equiv && vr1->equiv && vr0->equiv != vr1->equiv)
6279 bitmap_and_into (vr0->equiv, vr1->equiv);
6280 else if (vr0->equiv && !vr1->equiv)
6281 bitmap_clear (vr0->equiv);
6286 else if (vr0->type == VR_ANTI_RANGE || vr1->type == VR_ANTI_RANGE)
6288 /* For a numeric range [VAL1, VAL2] and an anti-range ~[VAL3, VAL4],
6289 only handle the case where the ranges have an empty intersection.
6290 The result of the meet operation is the anti-range. */
6291 if (!symbolic_range_p (vr0)
6292 && !symbolic_range_p (vr1)
6293 && !value_ranges_intersect_p (vr0, vr1))
6295 /* Copy most of VR1 into VR0. Don't copy VR1's equivalence
6296 set. We need to compute the intersection of the two
6297 equivalence sets. */
6298 if (vr1->type == VR_ANTI_RANGE)
6299 set_value_range (vr0, vr1->type, vr1->min, vr1->max, vr0->equiv);
6301 /* The resulting set of equivalences is the intersection of
6303 if (vr0->equiv && vr1->equiv && vr0->equiv != vr1->equiv)
6304 bitmap_and_into (vr0->equiv, vr1->equiv);
6305 else if (vr0->equiv && !vr1->equiv)
6306 bitmap_clear (vr0->equiv);
6317 /* Failed to find an efficient meet. Before giving up and setting
6318 the result to VARYING, see if we can at least derive a useful
6319 anti-range. FIXME, all this nonsense about distinguishing
6320 anti-ranges from ranges is necessary because of the odd
6321 semantics of range_includes_zero_p and friends. */
6322 if (!symbolic_range_p (vr0)
6323 && ((vr0->type == VR_RANGE && !range_includes_zero_p (vr0))
6324 || (vr0->type == VR_ANTI_RANGE && range_includes_zero_p (vr0)))
6325 && !symbolic_range_p (vr1)
6326 && ((vr1->type == VR_RANGE && !range_includes_zero_p (vr1))
6327 || (vr1->type == VR_ANTI_RANGE && range_includes_zero_p (vr1))))
6329 set_value_range_to_nonnull (vr0, TREE_TYPE (vr0->min));
6331 /* Since this meet operation did not result from the meeting of
6332 two equivalent names, VR0 cannot have any equivalences. */
6334 bitmap_clear (vr0->equiv);
6337 set_value_range_to_varying (vr0);
6341 /* Visit all arguments for PHI node PHI that flow through executable
6342 edges. If a valid value range can be derived from all the incoming
6343 value ranges, set a new range for the LHS of PHI. */
6345 static enum ssa_prop_result
6346 vrp_visit_phi_node (gimple phi)
6349 tree lhs = PHI_RESULT (phi);
6350 value_range_t *lhs_vr = get_value_range (lhs);
6351 value_range_t vr_result = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
6352 int edges, old_edges;
6355 copy_value_range (&vr_result, lhs_vr);
6357 if (dump_file && (dump_flags & TDF_DETAILS))
6359 fprintf (dump_file, "\nVisiting PHI node: ");
6360 print_gimple_stmt (dump_file, phi, 0, dump_flags);
6364 for (i = 0; i < gimple_phi_num_args (phi); i++)
6366 edge e = gimple_phi_arg_edge (phi, i);
6368 if (dump_file && (dump_flags & TDF_DETAILS))
6371 "\n Argument #%d (%d -> %d %sexecutable)\n",
6372 (int) i, e->src->index, e->dest->index,
6373 (e->flags & EDGE_EXECUTABLE) ? "" : "not ");
6376 if (e->flags & EDGE_EXECUTABLE)
6378 tree arg = PHI_ARG_DEF (phi, i);
6379 value_range_t vr_arg;
6383 if (TREE_CODE (arg) == SSA_NAME)
6385 vr_arg = *(get_value_range (arg));
6389 if (is_overflow_infinity (arg))
6391 arg = copy_node (arg);
6392 TREE_OVERFLOW (arg) = 0;
6395 vr_arg.type = VR_RANGE;
6398 vr_arg.equiv = NULL;
6401 if (dump_file && (dump_flags & TDF_DETAILS))
6403 fprintf (dump_file, "\t");
6404 print_generic_expr (dump_file, arg, dump_flags);
6405 fprintf (dump_file, "\n\tValue: ");
6406 dump_value_range (dump_file, &vr_arg);
6407 fprintf (dump_file, "\n");
6410 vrp_meet (&vr_result, &vr_arg);
6412 if (vr_result.type == VR_VARYING)
6417 /* If this is a loop PHI node SCEV may known more about its
6420 && (l = loop_containing_stmt (phi))
6421 && l->header == gimple_bb (phi))
6422 adjust_range_with_scev (&vr_result, l, phi, lhs);
6424 if (vr_result.type == VR_VARYING)
6427 old_edges = vr_phi_edge_counts[SSA_NAME_VERSION (lhs)];
6428 vr_phi_edge_counts[SSA_NAME_VERSION (lhs)] = edges;
6430 /* To prevent infinite iterations in the algorithm, derive ranges
6431 when the new value is slightly bigger or smaller than the
6432 previous one. We don't do this if we have seen a new executable
6433 edge; this helps us avoid an overflow infinity for conditionals
6434 which are not in a loop. */
6435 if (lhs_vr->type == VR_RANGE && vr_result.type == VR_RANGE
6436 && edges <= old_edges)
6438 if (!POINTER_TYPE_P (TREE_TYPE (lhs)))
6440 int cmp_min = compare_values (lhs_vr->min, vr_result.min);
6441 int cmp_max = compare_values (lhs_vr->max, vr_result.max);
6443 /* If the new minimum is smaller or larger than the previous
6444 one, go all the way to -INF. In the first case, to avoid
6445 iterating millions of times to reach -INF, and in the
6446 other case to avoid infinite bouncing between different
6448 if (cmp_min > 0 || cmp_min < 0)
6450 /* If we will end up with a (-INF, +INF) range, set it to
6451 VARYING. Same if the previous max value was invalid for
6452 the type and we'd end up with vr_result.min > vr_result.max. */
6453 if (vrp_val_is_max (vr_result.max)
6454 || compare_values (TYPE_MIN_VALUE (TREE_TYPE (vr_result.min)),
6458 if (!needs_overflow_infinity (TREE_TYPE (vr_result.min))
6459 || !vrp_var_may_overflow (lhs, phi))
6460 vr_result.min = TYPE_MIN_VALUE (TREE_TYPE (vr_result.min));
6461 else if (supports_overflow_infinity (TREE_TYPE (vr_result.min)))
6463 negative_overflow_infinity (TREE_TYPE (vr_result.min));
6468 /* Similarly, if the new maximum is smaller or larger than
6469 the previous one, go all the way to +INF. */
6470 if (cmp_max < 0 || cmp_max > 0)
6472 /* If we will end up with a (-INF, +INF) range, set it to
6473 VARYING. Same if the previous min value was invalid for
6474 the type and we'd end up with vr_result.max < vr_result.min. */
6475 if (vrp_val_is_min (vr_result.min)
6476 || compare_values (TYPE_MAX_VALUE (TREE_TYPE (vr_result.max)),
6480 if (!needs_overflow_infinity (TREE_TYPE (vr_result.max))
6481 || !vrp_var_may_overflow (lhs, phi))
6482 vr_result.max = TYPE_MAX_VALUE (TREE_TYPE (vr_result.max));
6483 else if (supports_overflow_infinity (TREE_TYPE (vr_result.max)))
6485 positive_overflow_infinity (TREE_TYPE (vr_result.max));
6492 /* If the new range is different than the previous value, keep
6494 if (update_value_range (lhs, &vr_result))
6496 if (dump_file && (dump_flags & TDF_DETAILS))
6498 fprintf (dump_file, "Found new range for ");
6499 print_generic_expr (dump_file, lhs, 0);
6500 fprintf (dump_file, ": ");
6501 dump_value_range (dump_file, &vr_result);
6502 fprintf (dump_file, "\n\n");
6505 return SSA_PROP_INTERESTING;
6508 /* Nothing changed, don't add outgoing edges. */
6509 return SSA_PROP_NOT_INTERESTING;
6511 /* No match found. Set the LHS to VARYING. */
6513 set_value_range_to_varying (lhs_vr);
6514 return SSA_PROP_VARYING;
6517 /* Simplify boolean operations if the source is known
6518 to be already a boolean. */
6520 simplify_truth_ops_using_ranges (gimple_stmt_iterator *gsi, gimple stmt)
6522 enum tree_code rhs_code = gimple_assign_rhs_code (stmt);
6527 bool need_conversion;
6529 op0 = gimple_assign_rhs1 (stmt);
6530 if (TYPE_PRECISION (TREE_TYPE (op0)) != 1)
6532 if (TREE_CODE (op0) != SSA_NAME)
6534 vr = get_value_range (op0);
6536 val = compare_range_with_value (GE_EXPR, vr, integer_zero_node, &sop);
6537 if (!val || !integer_onep (val))
6540 val = compare_range_with_value (LE_EXPR, vr, integer_one_node, &sop);
6541 if (!val || !integer_onep (val))
6545 if (rhs_code == TRUTH_NOT_EXPR)
6548 op1 = build_int_cst (TREE_TYPE (op0), 1);
6552 op1 = gimple_assign_rhs2 (stmt);
6554 /* Reduce number of cases to handle. */
6555 if (is_gimple_min_invariant (op1))
6557 /* Exclude anything that should have been already folded. */
6558 if (rhs_code != EQ_EXPR
6559 && rhs_code != NE_EXPR
6560 && rhs_code != TRUTH_XOR_EXPR)
6563 if (!integer_zerop (op1)
6564 && !integer_onep (op1)
6565 && !integer_all_onesp (op1))
6568 /* Limit the number of cases we have to consider. */
6569 if (rhs_code == EQ_EXPR)
6572 op1 = fold_unary (TRUTH_NOT_EXPR, TREE_TYPE (op1), op1);
6577 /* Punt on A == B as there is no BIT_XNOR_EXPR. */
6578 if (rhs_code == EQ_EXPR)
6581 if (TYPE_PRECISION (TREE_TYPE (op1)) != 1)
6583 vr = get_value_range (op1);
6584 val = compare_range_with_value (GE_EXPR, vr, integer_zero_node, &sop);
6585 if (!val || !integer_onep (val))
6588 val = compare_range_with_value (LE_EXPR, vr, integer_one_node, &sop);
6589 if (!val || !integer_onep (val))
6595 if (sop && issue_strict_overflow_warning (WARN_STRICT_OVERFLOW_MISC))
6597 location_t location;
6599 if (!gimple_has_location (stmt))
6600 location = input_location;
6602 location = gimple_location (stmt);
6604 if (rhs_code == TRUTH_AND_EXPR || rhs_code == TRUTH_OR_EXPR)
6605 warning_at (location, OPT_Wstrict_overflow,
6606 _("assuming signed overflow does not occur when "
6607 "simplifying && or || to & or |"));
6609 warning_at (location, OPT_Wstrict_overflow,
6610 _("assuming signed overflow does not occur when "
6611 "simplifying ==, != or ! to identity or ^"));
6615 !useless_type_conversion_p (TREE_TYPE (gimple_assign_lhs (stmt)),
6618 /* Make sure to not sign-extend -1 as a boolean value. */
6620 && !TYPE_UNSIGNED (TREE_TYPE (op0))
6621 && TYPE_PRECISION (TREE_TYPE (op0)) == 1)
6626 case TRUTH_AND_EXPR:
6627 rhs_code = BIT_AND_EXPR;
6630 rhs_code = BIT_IOR_EXPR;
6632 case TRUTH_XOR_EXPR:
6634 if (integer_zerop (op1))
6636 gimple_assign_set_rhs_with_ops (gsi,
6637 need_conversion ? NOP_EXPR : SSA_NAME,
6639 update_stmt (gsi_stmt (*gsi));
6643 rhs_code = BIT_XOR_EXPR;
6649 if (need_conversion)
6652 gimple_assign_set_rhs_with_ops (gsi, rhs_code, op0, op1);
6653 update_stmt (gsi_stmt (*gsi));
6657 /* Simplify a division or modulo operator to a right shift or
6658 bitwise and if the first operand is unsigned or is greater
6659 than zero and the second operand is an exact power of two. */
6662 simplify_div_or_mod_using_ranges (gimple stmt)
6664 enum tree_code rhs_code = gimple_assign_rhs_code (stmt);
6666 tree op0 = gimple_assign_rhs1 (stmt);
6667 tree op1 = gimple_assign_rhs2 (stmt);
6668 value_range_t *vr = get_value_range (gimple_assign_rhs1 (stmt));
6670 if (TYPE_UNSIGNED (TREE_TYPE (op0)))
6672 val = integer_one_node;
6678 val = compare_range_with_value (GE_EXPR, vr, integer_zero_node, &sop);
6682 && integer_onep (val)
6683 && issue_strict_overflow_warning (WARN_STRICT_OVERFLOW_MISC))
6685 location_t location;
6687 if (!gimple_has_location (stmt))
6688 location = input_location;
6690 location = gimple_location (stmt);
6691 warning_at (location, OPT_Wstrict_overflow,
6692 "assuming signed overflow does not occur when "
6693 "simplifying %</%> or %<%%%> to %<>>%> or %<&%>");
6697 if (val && integer_onep (val))
6701 if (rhs_code == TRUNC_DIV_EXPR)
6703 t = build_int_cst (NULL_TREE, tree_log2 (op1));
6704 gimple_assign_set_rhs_code (stmt, RSHIFT_EXPR);
6705 gimple_assign_set_rhs1 (stmt, op0);
6706 gimple_assign_set_rhs2 (stmt, t);
6710 t = build_int_cst (TREE_TYPE (op1), 1);
6711 t = int_const_binop (MINUS_EXPR, op1, t, 0);
6712 t = fold_convert (TREE_TYPE (op0), t);
6714 gimple_assign_set_rhs_code (stmt, BIT_AND_EXPR);
6715 gimple_assign_set_rhs1 (stmt, op0);
6716 gimple_assign_set_rhs2 (stmt, t);
6726 /* If the operand to an ABS_EXPR is >= 0, then eliminate the
6727 ABS_EXPR. If the operand is <= 0, then simplify the
6728 ABS_EXPR into a NEGATE_EXPR. */
6731 simplify_abs_using_ranges (gimple stmt)
6734 tree op = gimple_assign_rhs1 (stmt);
6735 tree type = TREE_TYPE (op);
6736 value_range_t *vr = get_value_range (op);
6738 if (TYPE_UNSIGNED (type))
6740 val = integer_zero_node;
6746 val = compare_range_with_value (LE_EXPR, vr, integer_zero_node, &sop);
6750 val = compare_range_with_value (GE_EXPR, vr, integer_zero_node,
6755 if (integer_zerop (val))
6756 val = integer_one_node;
6757 else if (integer_onep (val))
6758 val = integer_zero_node;
6763 && (integer_onep (val) || integer_zerop (val)))
6765 if (sop && issue_strict_overflow_warning (WARN_STRICT_OVERFLOW_MISC))
6767 location_t location;
6769 if (!gimple_has_location (stmt))
6770 location = input_location;
6772 location = gimple_location (stmt);
6773 warning_at (location, OPT_Wstrict_overflow,
6774 "assuming signed overflow does not occur when "
6775 "simplifying %<abs (X)%> to %<X%> or %<-X%>");
6778 gimple_assign_set_rhs1 (stmt, op);
6779 if (integer_onep (val))
6780 gimple_assign_set_rhs_code (stmt, NEGATE_EXPR);
6782 gimple_assign_set_rhs_code (stmt, SSA_NAME);
6791 /* We are comparing trees OP0 and OP1 using COND_CODE. OP0 has
6792 a known value range VR.
6794 If there is one and only one value which will satisfy the
6795 conditional, then return that value. Else return NULL. */
6798 test_for_singularity (enum tree_code cond_code, tree op0,
6799 tree op1, value_range_t *vr)
6804 /* Extract minimum/maximum values which satisfy the
6805 the conditional as it was written. */
6806 if (cond_code == LE_EXPR || cond_code == LT_EXPR)
6808 /* This should not be negative infinity; there is no overflow
6810 min = TYPE_MIN_VALUE (TREE_TYPE (op0));
6813 if (cond_code == LT_EXPR && !is_overflow_infinity (max))
6815 tree one = build_int_cst (TREE_TYPE (op0), 1);
6816 max = fold_build2 (MINUS_EXPR, TREE_TYPE (op0), max, one);
6818 TREE_NO_WARNING (max) = 1;
6821 else if (cond_code == GE_EXPR || cond_code == GT_EXPR)
6823 /* This should not be positive infinity; there is no overflow
6825 max = TYPE_MAX_VALUE (TREE_TYPE (op0));
6828 if (cond_code == GT_EXPR && !is_overflow_infinity (min))
6830 tree one = build_int_cst (TREE_TYPE (op0), 1);
6831 min = fold_build2 (PLUS_EXPR, TREE_TYPE (op0), min, one);
6833 TREE_NO_WARNING (min) = 1;
6837 /* Now refine the minimum and maximum values using any
6838 value range information we have for op0. */
6841 if (compare_values (vr->min, min) == 1)
6843 if (compare_values (vr->max, max) == -1)
6846 /* If the new min/max values have converged to a single value,
6847 then there is only one value which can satisfy the condition,
6848 return that value. */
6849 if (operand_equal_p (min, max, 0) && is_gimple_min_invariant (min))
6855 /* Simplify a conditional using a relational operator to an equality
6856 test if the range information indicates only one value can satisfy
6857 the original conditional. */
6860 simplify_cond_using_ranges (gimple stmt)
6862 tree op0 = gimple_cond_lhs (stmt);
6863 tree op1 = gimple_cond_rhs (stmt);
6864 enum tree_code cond_code = gimple_cond_code (stmt);
6866 if (cond_code != NE_EXPR
6867 && cond_code != EQ_EXPR
6868 && TREE_CODE (op0) == SSA_NAME
6869 && INTEGRAL_TYPE_P (TREE_TYPE (op0))
6870 && is_gimple_min_invariant (op1))
6872 value_range_t *vr = get_value_range (op0);
6874 /* If we have range information for OP0, then we might be
6875 able to simplify this conditional. */
6876 if (vr->type == VR_RANGE)
6878 tree new_tree = test_for_singularity (cond_code, op0, op1, vr);
6884 fprintf (dump_file, "Simplified relational ");
6885 print_gimple_stmt (dump_file, stmt, 0, 0);
6886 fprintf (dump_file, " into ");
6889 gimple_cond_set_code (stmt, EQ_EXPR);
6890 gimple_cond_set_lhs (stmt, op0);
6891 gimple_cond_set_rhs (stmt, new_tree);
6897 print_gimple_stmt (dump_file, stmt, 0, 0);
6898 fprintf (dump_file, "\n");
6904 /* Try again after inverting the condition. We only deal
6905 with integral types here, so no need to worry about
6906 issues with inverting FP comparisons. */
6907 cond_code = invert_tree_comparison (cond_code, false);
6908 new_tree = test_for_singularity (cond_code, op0, op1, vr);
6914 fprintf (dump_file, "Simplified relational ");
6915 print_gimple_stmt (dump_file, stmt, 0, 0);
6916 fprintf (dump_file, " into ");
6919 gimple_cond_set_code (stmt, NE_EXPR);
6920 gimple_cond_set_lhs (stmt, op0);
6921 gimple_cond_set_rhs (stmt, new_tree);
6927 print_gimple_stmt (dump_file, stmt, 0, 0);
6928 fprintf (dump_file, "\n");
6939 /* Simplify a switch statement using the value range of the switch
6943 simplify_switch_using_ranges (gimple stmt)
6945 tree op = gimple_switch_index (stmt);
6950 size_t i = 0, j = 0, n, n2;
6954 if (TREE_CODE (op) == SSA_NAME)
6956 vr = get_value_range (op);
6958 /* We can only handle integer ranges. */
6959 if (vr->type != VR_RANGE
6960 || symbolic_range_p (vr))
6963 /* Find case label for min/max of the value range. */
6964 take_default = !find_case_label_range (stmt, vr->min, vr->max, &i, &j);
6966 else if (TREE_CODE (op) == INTEGER_CST)
6968 take_default = !find_case_label_index (stmt, 1, op, &i);
6982 n = gimple_switch_num_labels (stmt);
6984 /* Bail out if this is just all edges taken. */
6990 /* Build a new vector of taken case labels. */
6991 vec2 = make_tree_vec (j - i + 1 + (int)take_default);
6994 /* Add the default edge, if necessary. */
6996 TREE_VEC_ELT (vec2, n2++) = gimple_switch_default_label (stmt);
6998 for (; i <= j; ++i, ++n2)
6999 TREE_VEC_ELT (vec2, n2) = gimple_switch_label (stmt, i);
7001 /* Mark needed edges. */
7002 for (i = 0; i < n2; ++i)
7004 e = find_edge (gimple_bb (stmt),
7005 label_to_block (CASE_LABEL (TREE_VEC_ELT (vec2, i))));
7006 e->aux = (void *)-1;
7009 /* Queue not needed edges for later removal. */
7010 FOR_EACH_EDGE (e, ei, gimple_bb (stmt)->succs)
7012 if (e->aux == (void *)-1)
7018 if (dump_file && (dump_flags & TDF_DETAILS))
7020 fprintf (dump_file, "removing unreachable case label\n");
7022 VEC_safe_push (edge, heap, to_remove_edges, e);
7023 e->flags &= ~EDGE_EXECUTABLE;
7026 /* And queue an update for the stmt. */
7029 VEC_safe_push (switch_update, heap, to_update_switch_stmts, &su);
7033 /* Simplify STMT using ranges if possible. */
7036 simplify_stmt_using_ranges (gimple_stmt_iterator *gsi)
7038 gimple stmt = gsi_stmt (*gsi);
7039 if (is_gimple_assign (stmt))
7041 enum tree_code rhs_code = gimple_assign_rhs_code (stmt);
7047 case TRUTH_NOT_EXPR:
7048 case TRUTH_AND_EXPR:
7050 case TRUTH_XOR_EXPR:
7051 /* Transform EQ_EXPR, NE_EXPR, TRUTH_NOT_EXPR into BIT_XOR_EXPR
7052 or identity if the RHS is zero or one, and the LHS are known
7053 to be boolean values. Transform all TRUTH_*_EXPR into
7054 BIT_*_EXPR if both arguments are known to be boolean values. */
7055 if (INTEGRAL_TYPE_P (TREE_TYPE (gimple_assign_rhs1 (stmt))))
7056 return simplify_truth_ops_using_ranges (gsi, stmt);
7059 /* Transform TRUNC_DIV_EXPR and TRUNC_MOD_EXPR into RSHIFT_EXPR
7060 and BIT_AND_EXPR respectively if the first operand is greater
7061 than zero and the second operand is an exact power of two. */
7062 case TRUNC_DIV_EXPR:
7063 case TRUNC_MOD_EXPR:
7064 if (INTEGRAL_TYPE_P (TREE_TYPE (gimple_assign_rhs1 (stmt)))
7065 && integer_pow2p (gimple_assign_rhs2 (stmt)))
7066 return simplify_div_or_mod_using_ranges (stmt);
7069 /* Transform ABS (X) into X or -X as appropriate. */
7071 if (TREE_CODE (gimple_assign_rhs1 (stmt)) == SSA_NAME
7072 && INTEGRAL_TYPE_P (TREE_TYPE (gimple_assign_rhs1 (stmt))))
7073 return simplify_abs_using_ranges (stmt);
7080 else if (gimple_code (stmt) == GIMPLE_COND)
7081 return simplify_cond_using_ranges (stmt);
7082 else if (gimple_code (stmt) == GIMPLE_SWITCH)
7083 return simplify_switch_using_ranges (stmt);
7088 /* If the statement pointed by SI has a predicate whose value can be
7089 computed using the value range information computed by VRP, compute
7090 its value and return true. Otherwise, return false. */
7093 fold_predicate_in (gimple_stmt_iterator *si)
7095 bool assignment_p = false;
7097 gimple stmt = gsi_stmt (*si);
7099 if (is_gimple_assign (stmt)
7100 && TREE_CODE_CLASS (gimple_assign_rhs_code (stmt)) == tcc_comparison)
7102 assignment_p = true;
7103 val = vrp_evaluate_conditional (gimple_assign_rhs_code (stmt),
7104 gimple_assign_rhs1 (stmt),
7105 gimple_assign_rhs2 (stmt),
7108 else if (gimple_code (stmt) == GIMPLE_COND)
7109 val = vrp_evaluate_conditional (gimple_cond_code (stmt),
7110 gimple_cond_lhs (stmt),
7111 gimple_cond_rhs (stmt),
7119 val = fold_convert (gimple_expr_type (stmt), val);
7123 fprintf (dump_file, "Folding predicate ");
7124 print_gimple_expr (dump_file, stmt, 0, 0);
7125 fprintf (dump_file, " to ");
7126 print_generic_expr (dump_file, val, 0);
7127 fprintf (dump_file, "\n");
7130 if (is_gimple_assign (stmt))
7131 gimple_assign_set_rhs_from_tree (si, val);
7134 gcc_assert (gimple_code (stmt) == GIMPLE_COND);
7135 if (integer_zerop (val))
7136 gimple_cond_make_false (stmt);
7137 else if (integer_onep (val))
7138 gimple_cond_make_true (stmt);
7149 /* Callback for substitute_and_fold folding the stmt at *SI. */
7152 vrp_fold_stmt (gimple_stmt_iterator *si)
7154 if (fold_predicate_in (si))
7157 return simplify_stmt_using_ranges (si);
7160 /* Stack of dest,src equivalency pairs that need to be restored after
7161 each attempt to thread a block's incoming edge to an outgoing edge.
7163 A NULL entry is used to mark the end of pairs which need to be
7165 static VEC(tree,heap) *stack;
7167 /* A trivial wrapper so that we can present the generic jump threading
7168 code with a simple API for simplifying statements. STMT is the
7169 statement we want to simplify, WITHIN_STMT provides the location
7170 for any overflow warnings. */
7173 simplify_stmt_for_jump_threading (gimple stmt, gimple within_stmt)
7175 /* We only use VRP information to simplify conditionals. This is
7176 overly conservative, but it's unclear if doing more would be
7177 worth the compile time cost. */
7178 if (gimple_code (stmt) != GIMPLE_COND)
7181 return vrp_evaluate_conditional (gimple_cond_code (stmt),
7182 gimple_cond_lhs (stmt),
7183 gimple_cond_rhs (stmt), within_stmt);
7186 /* Blocks which have more than one predecessor and more than
7187 one successor present jump threading opportunities, i.e.,
7188 when the block is reached from a specific predecessor, we
7189 may be able to determine which of the outgoing edges will
7190 be traversed. When this optimization applies, we are able
7191 to avoid conditionals at runtime and we may expose secondary
7192 optimization opportunities.
7194 This routine is effectively a driver for the generic jump
7195 threading code. It basically just presents the generic code
7196 with edges that may be suitable for jump threading.
7198 Unlike DOM, we do not iterate VRP if jump threading was successful.
7199 While iterating may expose new opportunities for VRP, it is expected
7200 those opportunities would be very limited and the compile time cost
7201 to expose those opportunities would be significant.
7203 As jump threading opportunities are discovered, they are registered
7204 for later realization. */
7207 identify_jump_threads (void)
7214 /* Ugh. When substituting values earlier in this pass we can
7215 wipe the dominance information. So rebuild the dominator
7216 information as we need it within the jump threading code. */
7217 calculate_dominance_info (CDI_DOMINATORS);
7219 /* We do not allow VRP information to be used for jump threading
7220 across a back edge in the CFG. Otherwise it becomes too
7221 difficult to avoid eliminating loop exit tests. Of course
7222 EDGE_DFS_BACK is not accurate at this time so we have to
7224 mark_dfs_back_edges ();
7226 /* Do not thread across edges we are about to remove. Just marking
7227 them as EDGE_DFS_BACK will do. */
7228 for (i = 0; VEC_iterate (edge, to_remove_edges, i, e); ++i)
7229 e->flags |= EDGE_DFS_BACK;
7231 /* Allocate our unwinder stack to unwind any temporary equivalences
7232 that might be recorded. */
7233 stack = VEC_alloc (tree, heap, 20);
7235 /* To avoid lots of silly node creation, we create a single
7236 conditional and just modify it in-place when attempting to
7238 dummy = gimple_build_cond (EQ_EXPR,
7239 integer_zero_node, integer_zero_node,
7242 /* Walk through all the blocks finding those which present a
7243 potential jump threading opportunity. We could set this up
7244 as a dominator walker and record data during the walk, but
7245 I doubt it's worth the effort for the classes of jump
7246 threading opportunities we are trying to identify at this
7247 point in compilation. */
7252 /* If the generic jump threading code does not find this block
7253 interesting, then there is nothing to do. */
7254 if (! potentially_threadable_block (bb))
7257 /* We only care about blocks ending in a COND_EXPR. While there
7258 may be some value in handling SWITCH_EXPR here, I doubt it's
7259 terribly important. */
7260 last = gsi_stmt (gsi_last_bb (bb));
7261 if (gimple_code (last) != GIMPLE_COND)
7264 /* We're basically looking for any kind of conditional with
7265 integral type arguments. */
7266 if (TREE_CODE (gimple_cond_lhs (last)) == SSA_NAME
7267 && INTEGRAL_TYPE_P (TREE_TYPE (gimple_cond_lhs (last)))
7268 && (TREE_CODE (gimple_cond_rhs (last)) == SSA_NAME
7269 || is_gimple_min_invariant (gimple_cond_rhs (last)))
7270 && INTEGRAL_TYPE_P (TREE_TYPE (gimple_cond_rhs (last))))
7274 /* We've got a block with multiple predecessors and multiple
7275 successors which also ends in a suitable conditional. For
7276 each predecessor, see if we can thread it to a specific
7278 FOR_EACH_EDGE (e, ei, bb->preds)
7280 /* Do not thread across back edges or abnormal edges
7282 if (e->flags & (EDGE_DFS_BACK | EDGE_COMPLEX))
7285 thread_across_edge (dummy, e, true, &stack,
7286 simplify_stmt_for_jump_threading);
7291 /* We do not actually update the CFG or SSA graphs at this point as
7292 ASSERT_EXPRs are still in the IL and cfg cleanup code does not yet
7293 handle ASSERT_EXPRs gracefully. */
7296 /* We identified all the jump threading opportunities earlier, but could
7297 not transform the CFG at that time. This routine transforms the
7298 CFG and arranges for the dominator tree to be rebuilt if necessary.
7300 Note the SSA graph update will occur during the normal TODO
7301 processing by the pass manager. */
7303 finalize_jump_threads (void)
7305 thread_through_all_blocks (false);
7306 VEC_free (tree, heap, stack);
7310 /* Traverse all the blocks folding conditionals with known ranges. */
7316 prop_value_t *single_val_range;
7317 bool do_value_subst_p;
7321 fprintf (dump_file, "\nValue ranges after VRP:\n\n");
7322 dump_all_value_ranges (dump_file);
7323 fprintf (dump_file, "\n");
7326 /* We may have ended with ranges that have exactly one value. Those
7327 values can be substituted as any other const propagated
7328 value using substitute_and_fold. */
7329 single_val_range = XCNEWVEC (prop_value_t, num_ssa_names);
7331 do_value_subst_p = false;
7332 for (i = 0; i < num_ssa_names; i++)
7334 && vr_value[i]->type == VR_RANGE
7335 && vr_value[i]->min == vr_value[i]->max
7336 && is_gimple_min_invariant (vr_value[i]->min))
7338 single_val_range[i].value = vr_value[i]->min;
7339 do_value_subst_p = true;
7342 if (!do_value_subst_p)
7344 /* We found no single-valued ranges, don't waste time trying to
7345 do single value substitution in substitute_and_fold. */
7346 free (single_val_range);
7347 single_val_range = NULL;
7350 substitute_and_fold (single_val_range, vrp_fold_stmt, false);
7352 if (warn_array_bounds)
7353 check_all_array_refs ();
7355 /* We must identify jump threading opportunities before we release
7356 the datastructures built by VRP. */
7357 identify_jump_threads ();
7359 /* Free allocated memory. */
7360 for (i = 0; i < num_ssa_names; i++)
7363 BITMAP_FREE (vr_value[i]->equiv);
7367 free (single_val_range);
7369 free (vr_phi_edge_counts);
7371 /* So that we can distinguish between VRP data being available
7372 and not available. */
7374 vr_phi_edge_counts = NULL;
7378 /* Main entry point to VRP (Value Range Propagation). This pass is
7379 loosely based on J. R. C. Patterson, ``Accurate Static Branch
7380 Prediction by Value Range Propagation,'' in SIGPLAN Conference on
7381 Programming Language Design and Implementation, pp. 67-78, 1995.
7382 Also available at http://citeseer.ist.psu.edu/patterson95accurate.html
7384 This is essentially an SSA-CCP pass modified to deal with ranges
7385 instead of constants.
7387 While propagating ranges, we may find that two or more SSA name
7388 have equivalent, though distinct ranges. For instance,
7391 2 p_4 = ASSERT_EXPR <p_3, p_3 != 0>
7393 4 p_5 = ASSERT_EXPR <p_4, p_4 == q_2>;
7397 In the code above, pointer p_5 has range [q_2, q_2], but from the
7398 code we can also determine that p_5 cannot be NULL and, if q_2 had
7399 a non-varying range, p_5's range should also be compatible with it.
7401 These equivalences are created by two expressions: ASSERT_EXPR and
7402 copy operations. Since p_5 is an assertion on p_4, and p_4 was the
7403 result of another assertion, then we can use the fact that p_5 and
7404 p_4 are equivalent when evaluating p_5's range.
7406 Together with value ranges, we also propagate these equivalences
7407 between names so that we can take advantage of information from
7408 multiple ranges when doing final replacement. Note that this
7409 equivalency relation is transitive but not symmetric.
7411 In the example above, p_5 is equivalent to p_4, q_2 and p_3, but we
7412 cannot assert that q_2 is equivalent to p_5 because q_2 may be used
7413 in contexts where that assertion does not hold (e.g., in line 6).
7415 TODO, the main difference between this pass and Patterson's is that
7416 we do not propagate edge probabilities. We only compute whether
7417 edges can be taken or not. That is, instead of having a spectrum
7418 of jump probabilities between 0 and 1, we only deal with 0, 1 and
7419 DON'T KNOW. In the future, it may be worthwhile to propagate
7420 probabilities to aid branch prediction. */
7429 loop_optimizer_init (LOOPS_NORMAL | LOOPS_HAVE_RECORDED_EXITS);
7430 rewrite_into_loop_closed_ssa (NULL, TODO_update_ssa);
7433 insert_range_assertions ();
7435 to_remove_edges = VEC_alloc (edge, heap, 10);
7436 to_update_switch_stmts = VEC_alloc (switch_update, heap, 5);
7437 threadedge_initialize_values ();
7440 ssa_propagate (vrp_visit_stmt, vrp_visit_phi_node);
7443 /* ASSERT_EXPRs must be removed before finalizing jump threads
7444 as finalizing jump threads calls the CFG cleanup code which
7445 does not properly handle ASSERT_EXPRs. */
7446 remove_range_assertions ();
7448 /* If we exposed any new variables, go ahead and put them into
7449 SSA form now, before we handle jump threading. This simplifies
7450 interactions between rewriting of _DECL nodes into SSA form
7451 and rewriting SSA_NAME nodes into SSA form after block
7452 duplication and CFG manipulation. */
7453 update_ssa (TODO_update_ssa);
7455 finalize_jump_threads ();
7457 /* Remove dead edges from SWITCH_EXPR optimization. This leaves the
7458 CFG in a broken state and requires a cfg_cleanup run. */
7459 for (i = 0; VEC_iterate (edge, to_remove_edges, i, e); ++i)
7461 /* Update SWITCH_EXPR case label vector. */
7462 for (i = 0; VEC_iterate (switch_update, to_update_switch_stmts, i, su); ++i)
7465 size_t n = TREE_VEC_LENGTH (su->vec);
7467 gimple_switch_set_num_labels (su->stmt, n);
7468 for (j = 0; j < n; j++)
7469 gimple_switch_set_label (su->stmt, j, TREE_VEC_ELT (su->vec, j));
7470 /* As we may have replaced the default label with a regular one
7471 make sure to make it a real default label again. This ensures
7472 optimal expansion. */
7473 label = gimple_switch_default_label (su->stmt);
7474 CASE_LOW (label) = NULL_TREE;
7475 CASE_HIGH (label) = NULL_TREE;
7478 if (VEC_length (edge, to_remove_edges) > 0)
7479 free_dominance_info (CDI_DOMINATORS);
7481 VEC_free (edge, heap, to_remove_edges);
7482 VEC_free (switch_update, heap, to_update_switch_stmts);
7483 threadedge_finalize_values ();
7486 loop_optimizer_finalize ();
7493 return flag_tree_vrp != 0;
7496 struct gimple_opt_pass pass_vrp =
7501 gate_vrp, /* gate */
7502 execute_vrp, /* execute */
7505 0, /* static_pass_number */
7506 TV_TREE_VRP, /* tv_id */
7507 PROP_ssa, /* properties_required */
7508 0, /* properties_provided */
7509 0, /* properties_destroyed */
7510 0, /* todo_flags_start */
7515 | TODO_update_ssa /* todo_flags_finish */