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"
36 #include "diagnostic-core.h"
40 #include "tree-scalar-evolution.h"
41 #include "tree-ssa-propagate.h"
42 #include "tree-chrec.h"
45 /* Set of SSA names found live during the RPO traversal of the function
46 for still active basic-blocks. */
49 /* Return true if the SSA name NAME is live on the edge E. */
52 live_on_edge (edge e, tree name)
54 return (live[e->dest->index]
55 && TEST_BIT (live[e->dest->index], SSA_NAME_VERSION (name)));
58 /* Local functions. */
59 static int compare_values (tree val1, tree val2);
60 static int compare_values_warnv (tree val1, tree val2, bool *);
61 static void vrp_meet (value_range_t *, value_range_t *);
62 static tree vrp_evaluate_conditional_warnv_with_ops (enum tree_code,
63 tree, tree, bool, bool *,
66 /* Location information for ASSERT_EXPRs. Each instance of this
67 structure describes an ASSERT_EXPR for an SSA name. Since a single
68 SSA name may have more than one assertion associated with it, these
69 locations are kept in a linked list attached to the corresponding
73 /* Basic block where the assertion would be inserted. */
76 /* Some assertions need to be inserted on an edge (e.g., assertions
77 generated by COND_EXPRs). In those cases, BB will be NULL. */
80 /* Pointer to the statement that generated this assertion. */
81 gimple_stmt_iterator si;
83 /* Predicate code for the ASSERT_EXPR. Must be COMPARISON_CLASS_P. */
84 enum tree_code comp_code;
86 /* Value being compared against. */
89 /* Expression to compare. */
92 /* Next node in the linked list. */
93 struct assert_locus_d *next;
96 typedef struct assert_locus_d *assert_locus_t;
98 /* If bit I is present, it means that SSA name N_i has a list of
99 assertions that should be inserted in the IL. */
100 static bitmap need_assert_for;
102 /* Array of locations lists where to insert assertions. ASSERTS_FOR[I]
103 holds a list of ASSERT_LOCUS_T nodes that describe where
104 ASSERT_EXPRs for SSA name N_I should be inserted. */
105 static assert_locus_t *asserts_for;
107 /* Value range array. After propagation, VR_VALUE[I] holds the range
108 of values that SSA name N_I may take. */
109 static value_range_t **vr_value;
111 /* For a PHI node which sets SSA name N_I, VR_COUNTS[I] holds the
112 number of executable edges we saw the last time we visited the
114 static int *vr_phi_edge_counts;
121 static VEC (edge, heap) *to_remove_edges;
122 DEF_VEC_O(switch_update);
123 DEF_VEC_ALLOC_O(switch_update, heap);
124 static VEC (switch_update, heap) *to_update_switch_stmts;
127 /* Return the maximum value for TYPE. */
130 vrp_val_max (const_tree type)
132 if (!INTEGRAL_TYPE_P (type))
135 return TYPE_MAX_VALUE (type);
138 /* Return the minimum value for TYPE. */
141 vrp_val_min (const_tree type)
143 if (!INTEGRAL_TYPE_P (type))
146 return TYPE_MIN_VALUE (type);
149 /* Return whether VAL is equal to the maximum value of its type. This
150 will be true for a positive overflow infinity. We can't do a
151 simple equality comparison with TYPE_MAX_VALUE because C typedefs
152 and Ada subtypes can produce types whose TYPE_MAX_VALUE is not ==
153 to the integer constant with the same value in the type. */
156 vrp_val_is_max (const_tree val)
158 tree type_max = vrp_val_max (TREE_TYPE (val));
159 return (val == type_max
160 || (type_max != NULL_TREE
161 && operand_equal_p (val, type_max, 0)));
164 /* Return whether VAL is equal to the minimum value of its type. This
165 will be true for a negative overflow infinity. */
168 vrp_val_is_min (const_tree val)
170 tree type_min = vrp_val_min (TREE_TYPE (val));
171 return (val == type_min
172 || (type_min != NULL_TREE
173 && operand_equal_p (val, type_min, 0)));
177 /* Return whether TYPE should use an overflow infinity distinct from
178 TYPE_{MIN,MAX}_VALUE. We use an overflow infinity value to
179 represent a signed overflow during VRP computations. An infinity
180 is distinct from a half-range, which will go from some number to
181 TYPE_{MIN,MAX}_VALUE. */
184 needs_overflow_infinity (const_tree type)
186 return INTEGRAL_TYPE_P (type) && !TYPE_OVERFLOW_WRAPS (type);
189 /* Return whether TYPE can support our overflow infinity
190 representation: we use the TREE_OVERFLOW flag, which only exists
191 for constants. If TYPE doesn't support this, we don't optimize
192 cases which would require signed overflow--we drop them to
196 supports_overflow_infinity (const_tree type)
198 tree min = vrp_val_min (type), max = vrp_val_max (type);
199 #ifdef ENABLE_CHECKING
200 gcc_assert (needs_overflow_infinity (type));
202 return (min != NULL_TREE
203 && CONSTANT_CLASS_P (min)
205 && CONSTANT_CLASS_P (max));
208 /* VAL is the maximum or minimum value of a type. Return a
209 corresponding overflow infinity. */
212 make_overflow_infinity (tree val)
214 #ifdef ENABLE_CHECKING
215 gcc_assert (val != NULL_TREE && CONSTANT_CLASS_P (val));
217 val = copy_node (val);
218 TREE_OVERFLOW (val) = 1;
222 /* Return a negative overflow infinity for TYPE. */
225 negative_overflow_infinity (tree type)
227 #ifdef ENABLE_CHECKING
228 gcc_assert (supports_overflow_infinity (type));
230 return make_overflow_infinity (vrp_val_min (type));
233 /* Return a positive overflow infinity for TYPE. */
236 positive_overflow_infinity (tree type)
238 #ifdef ENABLE_CHECKING
239 gcc_assert (supports_overflow_infinity (type));
241 return make_overflow_infinity (vrp_val_max (type));
244 /* Return whether VAL is a negative overflow infinity. */
247 is_negative_overflow_infinity (const_tree val)
249 return (needs_overflow_infinity (TREE_TYPE (val))
250 && CONSTANT_CLASS_P (val)
251 && TREE_OVERFLOW (val)
252 && vrp_val_is_min (val));
255 /* Return whether VAL is a positive overflow infinity. */
258 is_positive_overflow_infinity (const_tree val)
260 return (needs_overflow_infinity (TREE_TYPE (val))
261 && CONSTANT_CLASS_P (val)
262 && TREE_OVERFLOW (val)
263 && vrp_val_is_max (val));
266 /* Return whether VAL is a positive or negative overflow infinity. */
269 is_overflow_infinity (const_tree val)
271 return (needs_overflow_infinity (TREE_TYPE (val))
272 && CONSTANT_CLASS_P (val)
273 && TREE_OVERFLOW (val)
274 && (vrp_val_is_min (val) || vrp_val_is_max (val)));
277 /* Return whether STMT has a constant rhs that is_overflow_infinity. */
280 stmt_overflow_infinity (gimple stmt)
282 if (is_gimple_assign (stmt)
283 && get_gimple_rhs_class (gimple_assign_rhs_code (stmt)) ==
285 return is_overflow_infinity (gimple_assign_rhs1 (stmt));
289 /* If VAL is now an overflow infinity, return VAL. Otherwise, return
290 the same value with TREE_OVERFLOW clear. This can be used to avoid
291 confusing a regular value with an overflow value. */
294 avoid_overflow_infinity (tree val)
296 if (!is_overflow_infinity (val))
299 if (vrp_val_is_max (val))
300 return vrp_val_max (TREE_TYPE (val));
303 #ifdef ENABLE_CHECKING
304 gcc_assert (vrp_val_is_min (val));
306 return vrp_val_min (TREE_TYPE (val));
311 /* Return true if ARG is marked with the nonnull attribute in the
312 current function signature. */
315 nonnull_arg_p (const_tree arg)
317 tree t, attrs, fntype;
318 unsigned HOST_WIDE_INT arg_num;
320 gcc_assert (TREE_CODE (arg) == PARM_DECL && POINTER_TYPE_P (TREE_TYPE (arg)));
322 /* The static chain decl is always non null. */
323 if (arg == cfun->static_chain_decl)
326 fntype = TREE_TYPE (current_function_decl);
327 attrs = lookup_attribute ("nonnull", TYPE_ATTRIBUTES (fntype));
329 /* If "nonnull" wasn't specified, we know nothing about the argument. */
330 if (attrs == NULL_TREE)
333 /* If "nonnull" applies to all the arguments, then ARG is non-null. */
334 if (TREE_VALUE (attrs) == NULL_TREE)
337 /* Get the position number for ARG in the function signature. */
338 for (arg_num = 1, t = DECL_ARGUMENTS (current_function_decl);
340 t = TREE_CHAIN (t), arg_num++)
346 gcc_assert (t == arg);
348 /* Now see if ARG_NUM is mentioned in the nonnull list. */
349 for (t = TREE_VALUE (attrs); t; t = TREE_CHAIN (t))
351 if (compare_tree_int (TREE_VALUE (t), arg_num) == 0)
359 /* Set value range VR to VR_VARYING. */
362 set_value_range_to_varying (value_range_t *vr)
364 vr->type = VR_VARYING;
365 vr->min = vr->max = NULL_TREE;
367 bitmap_clear (vr->equiv);
371 /* Set value range VR to {T, MIN, MAX, EQUIV}. */
374 set_value_range (value_range_t *vr, enum value_range_type t, tree min,
375 tree max, bitmap equiv)
377 #if defined ENABLE_CHECKING
378 /* Check the validity of the range. */
379 if (t == VR_RANGE || t == VR_ANTI_RANGE)
383 gcc_assert (min && max);
385 if (INTEGRAL_TYPE_P (TREE_TYPE (min)) && t == VR_ANTI_RANGE)
386 gcc_assert (!vrp_val_is_min (min) || !vrp_val_is_max (max));
388 cmp = compare_values (min, max);
389 gcc_assert (cmp == 0 || cmp == -1 || cmp == -2);
391 if (needs_overflow_infinity (TREE_TYPE (min)))
392 gcc_assert (!is_overflow_infinity (min)
393 || !is_overflow_infinity (max));
396 if (t == VR_UNDEFINED || t == VR_VARYING)
397 gcc_assert (min == NULL_TREE && max == NULL_TREE);
399 if (t == VR_UNDEFINED || t == VR_VARYING)
400 gcc_assert (equiv == NULL || bitmap_empty_p (equiv));
407 /* Since updating the equivalence set involves deep copying the
408 bitmaps, only do it if absolutely necessary. */
409 if (vr->equiv == NULL
411 vr->equiv = BITMAP_ALLOC (NULL);
413 if (equiv != vr->equiv)
415 if (equiv && !bitmap_empty_p (equiv))
416 bitmap_copy (vr->equiv, equiv);
418 bitmap_clear (vr->equiv);
423 /* Set value range VR to the canonical form of {T, MIN, MAX, EQUIV}.
424 This means adjusting T, MIN and MAX representing the case of a
425 wrapping range with MAX < MIN covering [MIN, type_max] U [type_min, MAX]
426 as anti-rage ~[MAX+1, MIN-1]. Likewise for wrapping anti-ranges.
427 In corner cases where MAX+1 or MIN-1 wraps this will fall back
429 This routine exists to ease canonicalization in the case where we
430 extract ranges from var + CST op limit. */
433 set_and_canonicalize_value_range (value_range_t *vr, enum value_range_type t,
434 tree min, tree max, bitmap equiv)
436 /* Nothing to canonicalize for symbolic or unknown or varying ranges. */
438 && t != VR_ANTI_RANGE)
439 || TREE_CODE (min) != INTEGER_CST
440 || TREE_CODE (max) != INTEGER_CST)
442 set_value_range (vr, t, min, max, equiv);
446 /* Wrong order for min and max, to swap them and the VR type we need
448 if (tree_int_cst_lt (max, min))
450 tree one = build_int_cst (TREE_TYPE (min), 1);
451 tree tmp = int_const_binop (PLUS_EXPR, max, one, 0);
452 max = int_const_binop (MINUS_EXPR, min, one, 0);
455 /* There's one corner case, if we had [C+1, C] before we now have
456 that again. But this represents an empty value range, so drop
457 to varying in this case. */
458 if (tree_int_cst_lt (max, min))
460 set_value_range_to_varying (vr);
464 t = t == VR_RANGE ? VR_ANTI_RANGE : VR_RANGE;
467 /* Anti-ranges that can be represented as ranges should be so. */
468 if (t == VR_ANTI_RANGE)
470 bool is_min = vrp_val_is_min (min);
471 bool is_max = vrp_val_is_max (max);
473 if (is_min && is_max)
475 /* We cannot deal with empty ranges, drop to varying. */
476 set_value_range_to_varying (vr);
480 /* As a special exception preserve non-null ranges. */
481 && !(TYPE_UNSIGNED (TREE_TYPE (min))
482 && integer_zerop (max)))
484 tree one = build_int_cst (TREE_TYPE (max), 1);
485 min = int_const_binop (PLUS_EXPR, max, one, 0);
486 max = vrp_val_max (TREE_TYPE (max));
491 tree one = build_int_cst (TREE_TYPE (min), 1);
492 max = int_const_binop (MINUS_EXPR, min, one, 0);
493 min = vrp_val_min (TREE_TYPE (min));
498 set_value_range (vr, t, min, max, equiv);
501 /* Copy value range FROM into value range TO. */
504 copy_value_range (value_range_t *to, value_range_t *from)
506 set_value_range (to, from->type, from->min, from->max, from->equiv);
509 /* Set value range VR to a single value. This function is only called
510 with values we get from statements, and exists to clear the
511 TREE_OVERFLOW flag so that we don't think we have an overflow
512 infinity when we shouldn't. */
515 set_value_range_to_value (value_range_t *vr, tree val, bitmap equiv)
517 gcc_assert (is_gimple_min_invariant (val));
518 val = avoid_overflow_infinity (val);
519 set_value_range (vr, VR_RANGE, val, val, equiv);
522 /* Set value range VR to a non-negative range of type TYPE.
523 OVERFLOW_INFINITY indicates whether to use an overflow infinity
524 rather than TYPE_MAX_VALUE; this should be true if we determine
525 that the range is nonnegative based on the assumption that signed
526 overflow does not occur. */
529 set_value_range_to_nonnegative (value_range_t *vr, tree type,
530 bool overflow_infinity)
534 if (overflow_infinity && !supports_overflow_infinity (type))
536 set_value_range_to_varying (vr);
540 zero = build_int_cst (type, 0);
541 set_value_range (vr, VR_RANGE, zero,
543 ? positive_overflow_infinity (type)
544 : TYPE_MAX_VALUE (type)),
548 /* Set value range VR to a non-NULL range of type TYPE. */
551 set_value_range_to_nonnull (value_range_t *vr, tree type)
553 tree zero = build_int_cst (type, 0);
554 set_value_range (vr, VR_ANTI_RANGE, zero, zero, vr->equiv);
558 /* Set value range VR to a NULL range of type TYPE. */
561 set_value_range_to_null (value_range_t *vr, tree type)
563 set_value_range_to_value (vr, build_int_cst (type, 0), vr->equiv);
567 /* Set value range VR to a range of a truthvalue of type TYPE. */
570 set_value_range_to_truthvalue (value_range_t *vr, tree type)
572 if (TYPE_PRECISION (type) == 1)
573 set_value_range_to_varying (vr);
575 set_value_range (vr, VR_RANGE,
576 build_int_cst (type, 0), build_int_cst (type, 1),
581 /* Set value range VR to VR_UNDEFINED. */
584 set_value_range_to_undefined (value_range_t *vr)
586 vr->type = VR_UNDEFINED;
587 vr->min = vr->max = NULL_TREE;
589 bitmap_clear (vr->equiv);
593 /* If abs (min) < abs (max), set VR to [-max, max], if
594 abs (min) >= abs (max), set VR to [-min, min]. */
597 abs_extent_range (value_range_t *vr, tree min, tree max)
601 gcc_assert (TREE_CODE (min) == INTEGER_CST);
602 gcc_assert (TREE_CODE (max) == INTEGER_CST);
603 gcc_assert (INTEGRAL_TYPE_P (TREE_TYPE (min)));
604 gcc_assert (!TYPE_UNSIGNED (TREE_TYPE (min)));
605 min = fold_unary (ABS_EXPR, TREE_TYPE (min), min);
606 max = fold_unary (ABS_EXPR, TREE_TYPE (max), max);
607 if (TREE_OVERFLOW (min) || TREE_OVERFLOW (max))
609 set_value_range_to_varying (vr);
612 cmp = compare_values (min, max);
614 min = fold_unary (NEGATE_EXPR, TREE_TYPE (min), max);
615 else if (cmp == 0 || cmp == 1)
618 min = fold_unary (NEGATE_EXPR, TREE_TYPE (min), min);
622 set_value_range_to_varying (vr);
625 set_and_canonicalize_value_range (vr, VR_RANGE, min, max, NULL);
629 /* Return value range information for VAR.
631 If we have no values ranges recorded (ie, VRP is not running), then
632 return NULL. Otherwise create an empty range if none existed for VAR. */
634 static value_range_t *
635 get_value_range (const_tree var)
639 unsigned ver = SSA_NAME_VERSION (var);
641 /* If we have no recorded ranges, then return NULL. */
649 /* Create a default value range. */
650 vr_value[ver] = vr = XCNEW (value_range_t);
652 /* Defer allocating the equivalence set. */
655 /* If VAR is a default definition, the variable can take any value
657 sym = SSA_NAME_VAR (var);
658 if (SSA_NAME_IS_DEFAULT_DEF (var))
660 /* Try to use the "nonnull" attribute to create ~[0, 0]
661 anti-ranges for pointers. Note that this is only valid with
662 default definitions of PARM_DECLs. */
663 if (TREE_CODE (sym) == PARM_DECL
664 && POINTER_TYPE_P (TREE_TYPE (sym))
665 && nonnull_arg_p (sym))
666 set_value_range_to_nonnull (vr, TREE_TYPE (sym));
668 set_value_range_to_varying (vr);
674 /* Return true, if VAL1 and VAL2 are equal values for VRP purposes. */
677 vrp_operand_equal_p (const_tree val1, const_tree val2)
681 if (!val1 || !val2 || !operand_equal_p (val1, val2, 0))
683 if (is_overflow_infinity (val1))
684 return is_overflow_infinity (val2);
688 /* Return true, if the bitmaps B1 and B2 are equal. */
691 vrp_bitmap_equal_p (const_bitmap b1, const_bitmap b2)
695 && bitmap_equal_p (b1, b2)));
698 /* Update the value range and equivalence set for variable VAR to
699 NEW_VR. Return true if NEW_VR is different from VAR's previous
702 NOTE: This function assumes that NEW_VR is a temporary value range
703 object created for the sole purpose of updating VAR's range. The
704 storage used by the equivalence set from NEW_VR will be freed by
705 this function. Do not call update_value_range when NEW_VR
706 is the range object associated with another SSA name. */
709 update_value_range (const_tree var, value_range_t *new_vr)
711 value_range_t *old_vr;
714 /* Update the value range, if necessary. */
715 old_vr = get_value_range (var);
716 is_new = old_vr->type != new_vr->type
717 || !vrp_operand_equal_p (old_vr->min, new_vr->min)
718 || !vrp_operand_equal_p (old_vr->max, new_vr->max)
719 || !vrp_bitmap_equal_p (old_vr->equiv, new_vr->equiv);
722 set_value_range (old_vr, new_vr->type, new_vr->min, new_vr->max,
725 BITMAP_FREE (new_vr->equiv);
731 /* Add VAR and VAR's equivalence set to EQUIV. This is the central
732 point where equivalence processing can be turned on/off. */
735 add_equivalence (bitmap *equiv, const_tree var)
737 unsigned ver = SSA_NAME_VERSION (var);
738 value_range_t *vr = vr_value[ver];
741 *equiv = BITMAP_ALLOC (NULL);
742 bitmap_set_bit (*equiv, ver);
744 bitmap_ior_into (*equiv, vr->equiv);
748 /* Return true if VR is ~[0, 0]. */
751 range_is_nonnull (value_range_t *vr)
753 return vr->type == VR_ANTI_RANGE
754 && integer_zerop (vr->min)
755 && integer_zerop (vr->max);
759 /* Return true if VR is [0, 0]. */
762 range_is_null (value_range_t *vr)
764 return vr->type == VR_RANGE
765 && integer_zerop (vr->min)
766 && integer_zerop (vr->max);
769 /* Return true if max and min of VR are INTEGER_CST. It's not necessary
773 range_int_cst_p (value_range_t *vr)
775 return (vr->type == VR_RANGE
776 && TREE_CODE (vr->max) == INTEGER_CST
777 && TREE_CODE (vr->min) == INTEGER_CST
778 && !TREE_OVERFLOW (vr->max)
779 && !TREE_OVERFLOW (vr->min));
782 /* Return true if VR is a INTEGER_CST singleton. */
785 range_int_cst_singleton_p (value_range_t *vr)
787 return (range_int_cst_p (vr)
788 && tree_int_cst_equal (vr->min, vr->max));
791 /* Return true if value range VR involves at least one symbol. */
794 symbolic_range_p (value_range_t *vr)
796 return (!is_gimple_min_invariant (vr->min)
797 || !is_gimple_min_invariant (vr->max));
800 /* Return true if value range VR uses an overflow infinity. */
803 overflow_infinity_range_p (value_range_t *vr)
805 return (vr->type == VR_RANGE
806 && (is_overflow_infinity (vr->min)
807 || is_overflow_infinity (vr->max)));
810 /* Return false if we can not make a valid comparison based on VR;
811 this will be the case if it uses an overflow infinity and overflow
812 is not undefined (i.e., -fno-strict-overflow is in effect).
813 Otherwise return true, and set *STRICT_OVERFLOW_P to true if VR
814 uses an overflow infinity. */
817 usable_range_p (value_range_t *vr, bool *strict_overflow_p)
819 gcc_assert (vr->type == VR_RANGE);
820 if (is_overflow_infinity (vr->min))
822 *strict_overflow_p = true;
823 if (!TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (vr->min)))
826 if (is_overflow_infinity (vr->max))
828 *strict_overflow_p = true;
829 if (!TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (vr->max)))
836 /* Like tree_expr_nonnegative_warnv_p, but this function uses value
837 ranges obtained so far. */
840 vrp_expr_computes_nonnegative (tree expr, bool *strict_overflow_p)
842 return (tree_expr_nonnegative_warnv_p (expr, strict_overflow_p)
843 || (TREE_CODE (expr) == SSA_NAME
844 && ssa_name_nonnegative_p (expr)));
847 /* Return true if the result of assignment STMT is know to be non-negative.
848 If the return value is based on the assumption that signed overflow is
849 undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't change
850 *STRICT_OVERFLOW_P.*/
853 gimple_assign_nonnegative_warnv_p (gimple stmt, bool *strict_overflow_p)
855 enum tree_code code = gimple_assign_rhs_code (stmt);
856 switch (get_gimple_rhs_class (code))
858 case GIMPLE_UNARY_RHS:
859 return tree_unary_nonnegative_warnv_p (gimple_assign_rhs_code (stmt),
860 gimple_expr_type (stmt),
861 gimple_assign_rhs1 (stmt),
863 case GIMPLE_BINARY_RHS:
864 return tree_binary_nonnegative_warnv_p (gimple_assign_rhs_code (stmt),
865 gimple_expr_type (stmt),
866 gimple_assign_rhs1 (stmt),
867 gimple_assign_rhs2 (stmt),
869 case GIMPLE_TERNARY_RHS:
871 case GIMPLE_SINGLE_RHS:
872 return tree_single_nonnegative_warnv_p (gimple_assign_rhs1 (stmt),
874 case GIMPLE_INVALID_RHS:
881 /* Return true if return value of call STMT is know to be non-negative.
882 If the return value is based on the assumption that signed overflow is
883 undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't change
884 *STRICT_OVERFLOW_P.*/
887 gimple_call_nonnegative_warnv_p (gimple stmt, bool *strict_overflow_p)
889 tree arg0 = gimple_call_num_args (stmt) > 0 ?
890 gimple_call_arg (stmt, 0) : NULL_TREE;
891 tree arg1 = gimple_call_num_args (stmt) > 1 ?
892 gimple_call_arg (stmt, 1) : NULL_TREE;
894 return tree_call_nonnegative_warnv_p (gimple_expr_type (stmt),
895 gimple_call_fndecl (stmt),
901 /* Return true if STMT is know to to compute a non-negative value.
902 If the return value is based on the assumption that signed overflow is
903 undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't change
904 *STRICT_OVERFLOW_P.*/
907 gimple_stmt_nonnegative_warnv_p (gimple stmt, bool *strict_overflow_p)
909 switch (gimple_code (stmt))
912 return gimple_assign_nonnegative_warnv_p (stmt, strict_overflow_p);
914 return gimple_call_nonnegative_warnv_p (stmt, strict_overflow_p);
920 /* Return true if the result of assignment STMT is know to be non-zero.
921 If the return value is based on the assumption that signed overflow is
922 undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't change
923 *STRICT_OVERFLOW_P.*/
926 gimple_assign_nonzero_warnv_p (gimple stmt, bool *strict_overflow_p)
928 enum tree_code code = gimple_assign_rhs_code (stmt);
929 switch (get_gimple_rhs_class (code))
931 case GIMPLE_UNARY_RHS:
932 return tree_unary_nonzero_warnv_p (gimple_assign_rhs_code (stmt),
933 gimple_expr_type (stmt),
934 gimple_assign_rhs1 (stmt),
936 case GIMPLE_BINARY_RHS:
937 return tree_binary_nonzero_warnv_p (gimple_assign_rhs_code (stmt),
938 gimple_expr_type (stmt),
939 gimple_assign_rhs1 (stmt),
940 gimple_assign_rhs2 (stmt),
942 case GIMPLE_TERNARY_RHS:
944 case GIMPLE_SINGLE_RHS:
945 return tree_single_nonzero_warnv_p (gimple_assign_rhs1 (stmt),
947 case GIMPLE_INVALID_RHS:
954 /* Return true if STMT is know to to compute a non-zero value.
955 If the return value is based on the assumption that signed overflow is
956 undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't change
957 *STRICT_OVERFLOW_P.*/
960 gimple_stmt_nonzero_warnv_p (gimple stmt, bool *strict_overflow_p)
962 switch (gimple_code (stmt))
965 return gimple_assign_nonzero_warnv_p (stmt, strict_overflow_p);
967 return gimple_alloca_call_p (stmt);
973 /* Like tree_expr_nonzero_warnv_p, but this function uses value ranges
977 vrp_stmt_computes_nonzero (gimple stmt, bool *strict_overflow_p)
979 if (gimple_stmt_nonzero_warnv_p (stmt, strict_overflow_p))
982 /* If we have an expression of the form &X->a, then the expression
983 is nonnull if X is nonnull. */
984 if (is_gimple_assign (stmt)
985 && gimple_assign_rhs_code (stmt) == ADDR_EXPR)
987 tree expr = gimple_assign_rhs1 (stmt);
988 tree base = get_base_address (TREE_OPERAND (expr, 0));
990 if (base != NULL_TREE
991 && TREE_CODE (base) == MEM_REF
992 && TREE_CODE (TREE_OPERAND (base, 0)) == SSA_NAME)
994 value_range_t *vr = get_value_range (TREE_OPERAND (base, 0));
995 if (range_is_nonnull (vr))
1003 /* Returns true if EXPR is a valid value (as expected by compare_values) --
1004 a gimple invariant, or SSA_NAME +- CST. */
1007 valid_value_p (tree expr)
1009 if (TREE_CODE (expr) == SSA_NAME)
1012 if (TREE_CODE (expr) == PLUS_EXPR
1013 || TREE_CODE (expr) == MINUS_EXPR)
1014 return (TREE_CODE (TREE_OPERAND (expr, 0)) == SSA_NAME
1015 && TREE_CODE (TREE_OPERAND (expr, 1)) == INTEGER_CST);
1017 return is_gimple_min_invariant (expr);
1023 -2 if those are incomparable. */
1025 operand_less_p (tree val, tree val2)
1027 /* LT is folded faster than GE and others. Inline the common case. */
1028 if (TREE_CODE (val) == INTEGER_CST && TREE_CODE (val2) == INTEGER_CST)
1030 if (TYPE_UNSIGNED (TREE_TYPE (val)))
1031 return INT_CST_LT_UNSIGNED (val, val2);
1034 if (INT_CST_LT (val, val2))
1042 fold_defer_overflow_warnings ();
1044 tcmp = fold_binary_to_constant (LT_EXPR, boolean_type_node, val, val2);
1046 fold_undefer_and_ignore_overflow_warnings ();
1049 || TREE_CODE (tcmp) != INTEGER_CST)
1052 if (!integer_zerop (tcmp))
1056 /* val >= val2, not considering overflow infinity. */
1057 if (is_negative_overflow_infinity (val))
1058 return is_negative_overflow_infinity (val2) ? 0 : 1;
1059 else if (is_positive_overflow_infinity (val2))
1060 return is_positive_overflow_infinity (val) ? 0 : 1;
1065 /* Compare two values VAL1 and VAL2. Return
1067 -2 if VAL1 and VAL2 cannot be compared at compile-time,
1070 +1 if VAL1 > VAL2, and
1073 This is similar to tree_int_cst_compare but supports pointer values
1074 and values that cannot be compared at compile time.
1076 If STRICT_OVERFLOW_P is not NULL, then set *STRICT_OVERFLOW_P to
1077 true if the return value is only valid if we assume that signed
1078 overflow is undefined. */
1081 compare_values_warnv (tree val1, tree val2, bool *strict_overflow_p)
1086 /* Below we rely on the fact that VAL1 and VAL2 are both pointers or
1088 gcc_assert (POINTER_TYPE_P (TREE_TYPE (val1))
1089 == POINTER_TYPE_P (TREE_TYPE (val2)));
1090 /* Convert the two values into the same type. This is needed because
1091 sizetype causes sign extension even for unsigned types. */
1092 val2 = fold_convert (TREE_TYPE (val1), val2);
1093 STRIP_USELESS_TYPE_CONVERSION (val2);
1095 if ((TREE_CODE (val1) == SSA_NAME
1096 || TREE_CODE (val1) == PLUS_EXPR
1097 || TREE_CODE (val1) == MINUS_EXPR)
1098 && (TREE_CODE (val2) == SSA_NAME
1099 || TREE_CODE (val2) == PLUS_EXPR
1100 || TREE_CODE (val2) == MINUS_EXPR))
1102 tree n1, c1, n2, c2;
1103 enum tree_code code1, code2;
1105 /* If VAL1 and VAL2 are of the form 'NAME [+-] CST' or 'NAME',
1106 return -1 or +1 accordingly. If VAL1 and VAL2 don't use the
1107 same name, return -2. */
1108 if (TREE_CODE (val1) == SSA_NAME)
1116 code1 = TREE_CODE (val1);
1117 n1 = TREE_OPERAND (val1, 0);
1118 c1 = TREE_OPERAND (val1, 1);
1119 if (tree_int_cst_sgn (c1) == -1)
1121 if (is_negative_overflow_infinity (c1))
1123 c1 = fold_unary_to_constant (NEGATE_EXPR, TREE_TYPE (c1), c1);
1126 code1 = code1 == MINUS_EXPR ? PLUS_EXPR : MINUS_EXPR;
1130 if (TREE_CODE (val2) == SSA_NAME)
1138 code2 = TREE_CODE (val2);
1139 n2 = TREE_OPERAND (val2, 0);
1140 c2 = TREE_OPERAND (val2, 1);
1141 if (tree_int_cst_sgn (c2) == -1)
1143 if (is_negative_overflow_infinity (c2))
1145 c2 = fold_unary_to_constant (NEGATE_EXPR, TREE_TYPE (c2), c2);
1148 code2 = code2 == MINUS_EXPR ? PLUS_EXPR : MINUS_EXPR;
1152 /* Both values must use the same name. */
1156 if (code1 == SSA_NAME
1157 && code2 == SSA_NAME)
1161 /* If overflow is defined we cannot simplify more. */
1162 if (!TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (val1)))
1165 if (strict_overflow_p != NULL
1166 && (code1 == SSA_NAME || !TREE_NO_WARNING (val1))
1167 && (code2 == SSA_NAME || !TREE_NO_WARNING (val2)))
1168 *strict_overflow_p = true;
1170 if (code1 == SSA_NAME)
1172 if (code2 == PLUS_EXPR)
1173 /* NAME < NAME + CST */
1175 else if (code2 == MINUS_EXPR)
1176 /* NAME > NAME - CST */
1179 else if (code1 == PLUS_EXPR)
1181 if (code2 == SSA_NAME)
1182 /* NAME + CST > NAME */
1184 else if (code2 == PLUS_EXPR)
1185 /* NAME + CST1 > NAME + CST2, if CST1 > CST2 */
1186 return compare_values_warnv (c1, c2, strict_overflow_p);
1187 else if (code2 == MINUS_EXPR)
1188 /* NAME + CST1 > NAME - CST2 */
1191 else if (code1 == MINUS_EXPR)
1193 if (code2 == SSA_NAME)
1194 /* NAME - CST < NAME */
1196 else if (code2 == PLUS_EXPR)
1197 /* NAME - CST1 < NAME + CST2 */
1199 else if (code2 == MINUS_EXPR)
1200 /* NAME - CST1 > NAME - CST2, if CST1 < CST2. Notice that
1201 C1 and C2 are swapped in the call to compare_values. */
1202 return compare_values_warnv (c2, c1, strict_overflow_p);
1208 /* We cannot compare non-constants. */
1209 if (!is_gimple_min_invariant (val1) || !is_gimple_min_invariant (val2))
1212 if (!POINTER_TYPE_P (TREE_TYPE (val1)))
1214 /* We cannot compare overflowed values, except for overflow
1216 if (TREE_OVERFLOW (val1) || TREE_OVERFLOW (val2))
1218 if (strict_overflow_p != NULL)
1219 *strict_overflow_p = true;
1220 if (is_negative_overflow_infinity (val1))
1221 return is_negative_overflow_infinity (val2) ? 0 : -1;
1222 else if (is_negative_overflow_infinity (val2))
1224 else if (is_positive_overflow_infinity (val1))
1225 return is_positive_overflow_infinity (val2) ? 0 : 1;
1226 else if (is_positive_overflow_infinity (val2))
1231 return tree_int_cst_compare (val1, val2);
1237 /* First see if VAL1 and VAL2 are not the same. */
1238 if (val1 == val2 || operand_equal_p (val1, val2, 0))
1241 /* If VAL1 is a lower address than VAL2, return -1. */
1242 if (operand_less_p (val1, val2) == 1)
1245 /* If VAL1 is a higher address than VAL2, return +1. */
1246 if (operand_less_p (val2, val1) == 1)
1249 /* If VAL1 is different than VAL2, return +2.
1250 For integer constants we either have already returned -1 or 1
1251 or they are equivalent. We still might succeed in proving
1252 something about non-trivial operands. */
1253 if (TREE_CODE (val1) != INTEGER_CST
1254 || TREE_CODE (val2) != INTEGER_CST)
1256 t = fold_binary_to_constant (NE_EXPR, boolean_type_node, val1, val2);
1257 if (t && integer_onep (t))
1265 /* Compare values like compare_values_warnv, but treat comparisons of
1266 nonconstants which rely on undefined overflow as incomparable. */
1269 compare_values (tree val1, tree val2)
1275 ret = compare_values_warnv (val1, val2, &sop);
1277 && (!is_gimple_min_invariant (val1) || !is_gimple_min_invariant (val2)))
1283 /* Return 1 if VAL is inside value range VR (VR->MIN <= VAL <= VR->MAX),
1284 0 if VAL is not inside VR,
1285 -2 if we cannot tell either way.
1287 FIXME, the current semantics of this functions are a bit quirky
1288 when taken in the context of VRP. In here we do not care
1289 about VR's type. If VR is the anti-range ~[3, 5] the call
1290 value_inside_range (4, VR) will return 1.
1292 This is counter-intuitive in a strict sense, but the callers
1293 currently expect this. They are calling the function
1294 merely to determine whether VR->MIN <= VAL <= VR->MAX. The
1295 callers are applying the VR_RANGE/VR_ANTI_RANGE semantics
1298 This also applies to value_ranges_intersect_p and
1299 range_includes_zero_p. The semantics of VR_RANGE and
1300 VR_ANTI_RANGE should be encoded here, but that also means
1301 adapting the users of these functions to the new semantics.
1303 Benchmark compile/20001226-1.c compilation time after changing this
1307 value_inside_range (tree val, value_range_t * vr)
1311 cmp1 = operand_less_p (val, vr->min);
1317 cmp2 = operand_less_p (vr->max, val);
1325 /* Return true if value ranges VR0 and VR1 have a non-empty
1328 Benchmark compile/20001226-1.c compilation time after changing this
1333 value_ranges_intersect_p (value_range_t *vr0, value_range_t *vr1)
1335 /* The value ranges do not intersect if the maximum of the first range is
1336 less than the minimum of the second range or vice versa.
1337 When those relations are unknown, we can't do any better. */
1338 if (operand_less_p (vr0->max, vr1->min) != 0)
1340 if (operand_less_p (vr1->max, vr0->min) != 0)
1346 /* Return true if VR includes the value zero, false otherwise. FIXME,
1347 currently this will return false for an anti-range like ~[-4, 3].
1348 This will be wrong when the semantics of value_inside_range are
1349 modified (currently the users of this function expect these
1353 range_includes_zero_p (value_range_t *vr)
1357 gcc_assert (vr->type != VR_UNDEFINED
1358 && vr->type != VR_VARYING
1359 && !symbolic_range_p (vr));
1361 zero = build_int_cst (TREE_TYPE (vr->min), 0);
1362 return (value_inside_range (zero, vr) == 1);
1365 /* Return true if T, an SSA_NAME, is known to be nonnegative. Return
1366 false otherwise or if no value range information is available. */
1369 ssa_name_nonnegative_p (const_tree t)
1371 value_range_t *vr = get_value_range (t);
1373 if (INTEGRAL_TYPE_P (t)
1374 && TYPE_UNSIGNED (t))
1380 /* Testing for VR_ANTI_RANGE is not useful here as any anti-range
1381 which would return a useful value should be encoded as a VR_RANGE. */
1382 if (vr->type == VR_RANGE)
1384 int result = compare_values (vr->min, integer_zero_node);
1386 return (result == 0 || result == 1);
1391 /* If OP has a value range with a single constant value return that,
1392 otherwise return NULL_TREE. This returns OP itself if OP is a
1396 op_with_constant_singleton_value_range (tree op)
1400 if (is_gimple_min_invariant (op))
1403 if (TREE_CODE (op) != SSA_NAME)
1406 vr = get_value_range (op);
1407 if (vr->type == VR_RANGE
1408 && operand_equal_p (vr->min, vr->max, 0)
1409 && is_gimple_min_invariant (vr->min))
1416 /* Extract value range information from an ASSERT_EXPR EXPR and store
1420 extract_range_from_assert (value_range_t *vr_p, tree expr)
1422 tree var, cond, limit, min, max, type;
1423 value_range_t *var_vr, *limit_vr;
1424 enum tree_code cond_code;
1426 var = ASSERT_EXPR_VAR (expr);
1427 cond = ASSERT_EXPR_COND (expr);
1429 gcc_assert (COMPARISON_CLASS_P (cond));
1431 /* Find VAR in the ASSERT_EXPR conditional. */
1432 if (var == TREE_OPERAND (cond, 0)
1433 || TREE_CODE (TREE_OPERAND (cond, 0)) == PLUS_EXPR
1434 || TREE_CODE (TREE_OPERAND (cond, 0)) == NOP_EXPR)
1436 /* If the predicate is of the form VAR COMP LIMIT, then we just
1437 take LIMIT from the RHS and use the same comparison code. */
1438 cond_code = TREE_CODE (cond);
1439 limit = TREE_OPERAND (cond, 1);
1440 cond = TREE_OPERAND (cond, 0);
1444 /* If the predicate is of the form LIMIT COMP VAR, then we need
1445 to flip around the comparison code to create the proper range
1447 cond_code = swap_tree_comparison (TREE_CODE (cond));
1448 limit = TREE_OPERAND (cond, 0);
1449 cond = TREE_OPERAND (cond, 1);
1452 limit = avoid_overflow_infinity (limit);
1454 type = TREE_TYPE (limit);
1455 gcc_assert (limit != var);
1457 /* For pointer arithmetic, we only keep track of pointer equality
1459 if (POINTER_TYPE_P (type) && cond_code != NE_EXPR && cond_code != EQ_EXPR)
1461 set_value_range_to_varying (vr_p);
1465 /* If LIMIT is another SSA name and LIMIT has a range of its own,
1466 try to use LIMIT's range to avoid creating symbolic ranges
1468 limit_vr = (TREE_CODE (limit) == SSA_NAME) ? get_value_range (limit) : NULL;
1470 /* LIMIT's range is only interesting if it has any useful information. */
1472 && (limit_vr->type == VR_UNDEFINED
1473 || limit_vr->type == VR_VARYING
1474 || symbolic_range_p (limit_vr)))
1477 /* Initially, the new range has the same set of equivalences of
1478 VAR's range. This will be revised before returning the final
1479 value. Since assertions may be chained via mutually exclusive
1480 predicates, we will need to trim the set of equivalences before
1482 gcc_assert (vr_p->equiv == NULL);
1483 add_equivalence (&vr_p->equiv, var);
1485 /* Extract a new range based on the asserted comparison for VAR and
1486 LIMIT's value range. Notice that if LIMIT has an anti-range, we
1487 will only use it for equality comparisons (EQ_EXPR). For any
1488 other kind of assertion, we cannot derive a range from LIMIT's
1489 anti-range that can be used to describe the new range. For
1490 instance, ASSERT_EXPR <x_2, x_2 <= b_4>. If b_4 is ~[2, 10],
1491 then b_4 takes on the ranges [-INF, 1] and [11, +INF]. There is
1492 no single range for x_2 that could describe LE_EXPR, so we might
1493 as well build the range [b_4, +INF] for it.
1494 One special case we handle is extracting a range from a
1495 range test encoded as (unsigned)var + CST <= limit. */
1496 if (TREE_CODE (cond) == NOP_EXPR
1497 || TREE_CODE (cond) == PLUS_EXPR)
1499 if (TREE_CODE (cond) == PLUS_EXPR)
1501 min = fold_build1 (NEGATE_EXPR, TREE_TYPE (TREE_OPERAND (cond, 1)),
1502 TREE_OPERAND (cond, 1));
1503 max = int_const_binop (PLUS_EXPR, limit, min, 0);
1504 cond = TREE_OPERAND (cond, 0);
1508 min = build_int_cst (TREE_TYPE (var), 0);
1512 /* Make sure to not set TREE_OVERFLOW on the final type
1513 conversion. We are willingly interpreting large positive
1514 unsigned values as negative singed values here. */
1515 min = force_fit_type_double (TREE_TYPE (var), tree_to_double_int (min),
1517 max = force_fit_type_double (TREE_TYPE (var), tree_to_double_int (max),
1520 /* We can transform a max, min range to an anti-range or
1521 vice-versa. Use set_and_canonicalize_value_range which does
1523 if (cond_code == LE_EXPR)
1524 set_and_canonicalize_value_range (vr_p, VR_RANGE,
1525 min, max, vr_p->equiv);
1526 else if (cond_code == GT_EXPR)
1527 set_and_canonicalize_value_range (vr_p, VR_ANTI_RANGE,
1528 min, max, vr_p->equiv);
1532 else if (cond_code == EQ_EXPR)
1534 enum value_range_type range_type;
1538 range_type = limit_vr->type;
1539 min = limit_vr->min;
1540 max = limit_vr->max;
1544 range_type = VR_RANGE;
1549 set_value_range (vr_p, range_type, min, max, vr_p->equiv);
1551 /* When asserting the equality VAR == LIMIT and LIMIT is another
1552 SSA name, the new range will also inherit the equivalence set
1554 if (TREE_CODE (limit) == SSA_NAME)
1555 add_equivalence (&vr_p->equiv, limit);
1557 else if (cond_code == NE_EXPR)
1559 /* As described above, when LIMIT's range is an anti-range and
1560 this assertion is an inequality (NE_EXPR), then we cannot
1561 derive anything from the anti-range. For instance, if
1562 LIMIT's range was ~[0, 0], the assertion 'VAR != LIMIT' does
1563 not imply that VAR's range is [0, 0]. So, in the case of
1564 anti-ranges, we just assert the inequality using LIMIT and
1567 If LIMIT_VR is a range, we can only use it to build a new
1568 anti-range if LIMIT_VR is a single-valued range. For
1569 instance, if LIMIT_VR is [0, 1], the predicate
1570 VAR != [0, 1] does not mean that VAR's range is ~[0, 1].
1571 Rather, it means that for value 0 VAR should be ~[0, 0]
1572 and for value 1, VAR should be ~[1, 1]. We cannot
1573 represent these ranges.
1575 The only situation in which we can build a valid
1576 anti-range is when LIMIT_VR is a single-valued range
1577 (i.e., LIMIT_VR->MIN == LIMIT_VR->MAX). In that case,
1578 build the anti-range ~[LIMIT_VR->MIN, LIMIT_VR->MAX]. */
1580 && limit_vr->type == VR_RANGE
1581 && compare_values (limit_vr->min, limit_vr->max) == 0)
1583 min = limit_vr->min;
1584 max = limit_vr->max;
1588 /* In any other case, we cannot use LIMIT's range to build a
1589 valid anti-range. */
1593 /* If MIN and MAX cover the whole range for their type, then
1594 just use the original LIMIT. */
1595 if (INTEGRAL_TYPE_P (type)
1596 && vrp_val_is_min (min)
1597 && vrp_val_is_max (max))
1600 set_value_range (vr_p, VR_ANTI_RANGE, min, max, vr_p->equiv);
1602 else if (cond_code == LE_EXPR || cond_code == LT_EXPR)
1604 min = TYPE_MIN_VALUE (type);
1606 if (limit_vr == NULL || limit_vr->type == VR_ANTI_RANGE)
1610 /* If LIMIT_VR is of the form [N1, N2], we need to build the
1611 range [MIN, N2] for LE_EXPR and [MIN, N2 - 1] for
1613 max = limit_vr->max;
1616 /* If the maximum value forces us to be out of bounds, simply punt.
1617 It would be pointless to try and do anything more since this
1618 all should be optimized away above us. */
1619 if ((cond_code == LT_EXPR
1620 && compare_values (max, min) == 0)
1621 || (CONSTANT_CLASS_P (max) && TREE_OVERFLOW (max)))
1622 set_value_range_to_varying (vr_p);
1625 /* For LT_EXPR, we create the range [MIN, MAX - 1]. */
1626 if (cond_code == LT_EXPR)
1628 tree one = build_int_cst (type, 1);
1629 max = fold_build2 (MINUS_EXPR, type, max, one);
1631 TREE_NO_WARNING (max) = 1;
1634 set_value_range (vr_p, VR_RANGE, min, max, vr_p->equiv);
1637 else if (cond_code == GE_EXPR || cond_code == GT_EXPR)
1639 max = TYPE_MAX_VALUE (type);
1641 if (limit_vr == NULL || limit_vr->type == VR_ANTI_RANGE)
1645 /* If LIMIT_VR is of the form [N1, N2], we need to build the
1646 range [N1, MAX] for GE_EXPR and [N1 + 1, MAX] for
1648 min = limit_vr->min;
1651 /* If the minimum value forces us to be out of bounds, simply punt.
1652 It would be pointless to try and do anything more since this
1653 all should be optimized away above us. */
1654 if ((cond_code == GT_EXPR
1655 && compare_values (min, max) == 0)
1656 || (CONSTANT_CLASS_P (min) && TREE_OVERFLOW (min)))
1657 set_value_range_to_varying (vr_p);
1660 /* For GT_EXPR, we create the range [MIN + 1, MAX]. */
1661 if (cond_code == GT_EXPR)
1663 tree one = build_int_cst (type, 1);
1664 min = fold_build2 (PLUS_EXPR, type, min, one);
1666 TREE_NO_WARNING (min) = 1;
1669 set_value_range (vr_p, VR_RANGE, min, max, vr_p->equiv);
1675 /* If VAR already had a known range, it may happen that the new
1676 range we have computed and VAR's range are not compatible. For
1680 p_6 = ASSERT_EXPR <p_5, p_5 == NULL>;
1682 p_8 = ASSERT_EXPR <p_6, p_6 != NULL>;
1684 While the above comes from a faulty program, it will cause an ICE
1685 later because p_8 and p_6 will have incompatible ranges and at
1686 the same time will be considered equivalent. A similar situation
1690 i_6 = ASSERT_EXPR <i_5, i_5 > 10>;
1692 i_7 = ASSERT_EXPR <i_6, i_6 < 5>;
1694 Again i_6 and i_7 will have incompatible ranges. It would be
1695 pointless to try and do anything with i_7's range because
1696 anything dominated by 'if (i_5 < 5)' will be optimized away.
1697 Note, due to the wa in which simulation proceeds, the statement
1698 i_7 = ASSERT_EXPR <...> we would never be visited because the
1699 conditional 'if (i_5 < 5)' always evaluates to false. However,
1700 this extra check does not hurt and may protect against future
1701 changes to VRP that may get into a situation similar to the
1702 NULL pointer dereference example.
1704 Note that these compatibility tests are only needed when dealing
1705 with ranges or a mix of range and anti-range. If VAR_VR and VR_P
1706 are both anti-ranges, they will always be compatible, because two
1707 anti-ranges will always have a non-empty intersection. */
1709 var_vr = get_value_range (var);
1711 /* We may need to make adjustments when VR_P and VAR_VR are numeric
1712 ranges or anti-ranges. */
1713 if (vr_p->type == VR_VARYING
1714 || vr_p->type == VR_UNDEFINED
1715 || var_vr->type == VR_VARYING
1716 || var_vr->type == VR_UNDEFINED
1717 || symbolic_range_p (vr_p)
1718 || symbolic_range_p (var_vr))
1721 if (var_vr->type == VR_RANGE && vr_p->type == VR_RANGE)
1723 /* If the two ranges have a non-empty intersection, we can
1724 refine the resulting range. Since the assert expression
1725 creates an equivalency and at the same time it asserts a
1726 predicate, we can take the intersection of the two ranges to
1727 get better precision. */
1728 if (value_ranges_intersect_p (var_vr, vr_p))
1730 /* Use the larger of the two minimums. */
1731 if (compare_values (vr_p->min, var_vr->min) == -1)
1736 /* Use the smaller of the two maximums. */
1737 if (compare_values (vr_p->max, var_vr->max) == 1)
1742 set_value_range (vr_p, vr_p->type, min, max, vr_p->equiv);
1746 /* The two ranges do not intersect, set the new range to
1747 VARYING, because we will not be able to do anything
1748 meaningful with it. */
1749 set_value_range_to_varying (vr_p);
1752 else if ((var_vr->type == VR_RANGE && vr_p->type == VR_ANTI_RANGE)
1753 || (var_vr->type == VR_ANTI_RANGE && vr_p->type == VR_RANGE))
1755 /* A range and an anti-range will cancel each other only if
1756 their ends are the same. For instance, in the example above,
1757 p_8's range ~[0, 0] and p_6's range [0, 0] are incompatible,
1758 so VR_P should be set to VR_VARYING. */
1759 if (compare_values (var_vr->min, vr_p->min) == 0
1760 && compare_values (var_vr->max, vr_p->max) == 0)
1761 set_value_range_to_varying (vr_p);
1764 tree min, max, anti_min, anti_max, real_min, real_max;
1767 /* We want to compute the logical AND of the two ranges;
1768 there are three cases to consider.
1771 1. The VR_ANTI_RANGE range is completely within the
1772 VR_RANGE and the endpoints of the ranges are
1773 different. In that case the resulting range
1774 should be whichever range is more precise.
1775 Typically that will be the VR_RANGE.
1777 2. The VR_ANTI_RANGE is completely disjoint from
1778 the VR_RANGE. In this case the resulting range
1779 should be the VR_RANGE.
1781 3. There is some overlap between the VR_ANTI_RANGE
1784 3a. If the high limit of the VR_ANTI_RANGE resides
1785 within the VR_RANGE, then the result is a new
1786 VR_RANGE starting at the high limit of the
1787 VR_ANTI_RANGE + 1 and extending to the
1788 high limit of the original VR_RANGE.
1790 3b. If the low limit of the VR_ANTI_RANGE resides
1791 within the VR_RANGE, then the result is a new
1792 VR_RANGE starting at the low limit of the original
1793 VR_RANGE and extending to the low limit of the
1794 VR_ANTI_RANGE - 1. */
1795 if (vr_p->type == VR_ANTI_RANGE)
1797 anti_min = vr_p->min;
1798 anti_max = vr_p->max;
1799 real_min = var_vr->min;
1800 real_max = var_vr->max;
1804 anti_min = var_vr->min;
1805 anti_max = var_vr->max;
1806 real_min = vr_p->min;
1807 real_max = vr_p->max;
1811 /* Case 1, VR_ANTI_RANGE completely within VR_RANGE,
1812 not including any endpoints. */
1813 if (compare_values (anti_max, real_max) == -1
1814 && compare_values (anti_min, real_min) == 1)
1816 /* If the range is covering the whole valid range of
1817 the type keep the anti-range. */
1818 if (!vrp_val_is_min (real_min)
1819 || !vrp_val_is_max (real_max))
1820 set_value_range (vr_p, VR_RANGE, real_min,
1821 real_max, vr_p->equiv);
1823 /* Case 2, VR_ANTI_RANGE completely disjoint from
1825 else if (compare_values (anti_min, real_max) == 1
1826 || compare_values (anti_max, real_min) == -1)
1828 set_value_range (vr_p, VR_RANGE, real_min,
1829 real_max, vr_p->equiv);
1831 /* Case 3a, the anti-range extends into the low
1832 part of the real range. Thus creating a new
1833 low for the real range. */
1834 else if (((cmp = compare_values (anti_max, real_min)) == 1
1836 && compare_values (anti_max, real_max) == -1)
1838 gcc_assert (!is_positive_overflow_infinity (anti_max));
1839 if (needs_overflow_infinity (TREE_TYPE (anti_max))
1840 && vrp_val_is_max (anti_max))
1842 if (!supports_overflow_infinity (TREE_TYPE (var_vr->min)))
1844 set_value_range_to_varying (vr_p);
1847 min = positive_overflow_infinity (TREE_TYPE (var_vr->min));
1849 else if (!POINTER_TYPE_P (TREE_TYPE (var_vr->min)))
1850 min = fold_build2 (PLUS_EXPR, TREE_TYPE (var_vr->min),
1852 build_int_cst (TREE_TYPE (var_vr->min), 1));
1854 min = fold_build2 (POINTER_PLUS_EXPR, TREE_TYPE (var_vr->min),
1855 anti_max, size_int (1));
1857 set_value_range (vr_p, VR_RANGE, min, max, vr_p->equiv);
1859 /* Case 3b, the anti-range extends into the high
1860 part of the real range. Thus creating a new
1861 higher for the real range. */
1862 else if (compare_values (anti_min, real_min) == 1
1863 && ((cmp = compare_values (anti_min, real_max)) == -1
1866 gcc_assert (!is_negative_overflow_infinity (anti_min));
1867 if (needs_overflow_infinity (TREE_TYPE (anti_min))
1868 && vrp_val_is_min (anti_min))
1870 if (!supports_overflow_infinity (TREE_TYPE (var_vr->min)))
1872 set_value_range_to_varying (vr_p);
1875 max = negative_overflow_infinity (TREE_TYPE (var_vr->min));
1877 else if (!POINTER_TYPE_P (TREE_TYPE (var_vr->min)))
1878 max = fold_build2 (MINUS_EXPR, TREE_TYPE (var_vr->min),
1880 build_int_cst (TREE_TYPE (var_vr->min), 1));
1882 max = fold_build2 (POINTER_PLUS_EXPR, TREE_TYPE (var_vr->min),
1886 set_value_range (vr_p, VR_RANGE, min, max, vr_p->equiv);
1893 /* Extract range information from SSA name VAR and store it in VR. If
1894 VAR has an interesting range, use it. Otherwise, create the
1895 range [VAR, VAR] and return it. This is useful in situations where
1896 we may have conditionals testing values of VARYING names. For
1903 Even if y_5 is deemed VARYING, we can determine that x_3 > y_5 is
1907 extract_range_from_ssa_name (value_range_t *vr, tree var)
1909 value_range_t *var_vr = get_value_range (var);
1911 if (var_vr->type != VR_UNDEFINED && var_vr->type != VR_VARYING)
1912 copy_value_range (vr, var_vr);
1914 set_value_range (vr, VR_RANGE, var, var, NULL);
1916 add_equivalence (&vr->equiv, var);
1920 /* Wrapper around int_const_binop. If the operation overflows and we
1921 are not using wrapping arithmetic, then adjust the result to be
1922 -INF or +INF depending on CODE, VAL1 and VAL2. This can return
1923 NULL_TREE if we need to use an overflow infinity representation but
1924 the type does not support it. */
1927 vrp_int_const_binop (enum tree_code code, tree val1, tree val2)
1931 res = int_const_binop (code, val1, val2, 0);
1933 /* If we are using unsigned arithmetic, operate symbolically
1934 on -INF and +INF as int_const_binop only handles signed overflow. */
1935 if (TYPE_UNSIGNED (TREE_TYPE (val1)))
1937 int checkz = compare_values (res, val1);
1938 bool overflow = false;
1940 /* Ensure that res = val1 [+*] val2 >= val1
1941 or that res = val1 - val2 <= val1. */
1942 if ((code == PLUS_EXPR
1943 && !(checkz == 1 || checkz == 0))
1944 || (code == MINUS_EXPR
1945 && !(checkz == 0 || checkz == -1)))
1949 /* Checking for multiplication overflow is done by dividing the
1950 output of the multiplication by the first input of the
1951 multiplication. If the result of that division operation is
1952 not equal to the second input of the multiplication, then the
1953 multiplication overflowed. */
1954 else if (code == MULT_EXPR && !integer_zerop (val1))
1956 tree tmp = int_const_binop (TRUNC_DIV_EXPR,
1959 int check = compare_values (tmp, val2);
1967 res = copy_node (res);
1968 TREE_OVERFLOW (res) = 1;
1972 else if (TYPE_OVERFLOW_WRAPS (TREE_TYPE (val1)))
1973 /* If the singed operation wraps then int_const_binop has done
1974 everything we want. */
1976 else if ((TREE_OVERFLOW (res)
1977 && !TREE_OVERFLOW (val1)
1978 && !TREE_OVERFLOW (val2))
1979 || is_overflow_infinity (val1)
1980 || is_overflow_infinity (val2))
1982 /* If the operation overflowed but neither VAL1 nor VAL2 are
1983 overflown, return -INF or +INF depending on the operation
1984 and the combination of signs of the operands. */
1985 int sgn1 = tree_int_cst_sgn (val1);
1986 int sgn2 = tree_int_cst_sgn (val2);
1988 if (needs_overflow_infinity (TREE_TYPE (res))
1989 && !supports_overflow_infinity (TREE_TYPE (res)))
1992 /* We have to punt on adding infinities of different signs,
1993 since we can't tell what the sign of the result should be.
1994 Likewise for subtracting infinities of the same sign. */
1995 if (((code == PLUS_EXPR && sgn1 != sgn2)
1996 || (code == MINUS_EXPR && sgn1 == sgn2))
1997 && is_overflow_infinity (val1)
1998 && is_overflow_infinity (val2))
2001 /* Don't try to handle division or shifting of infinities. */
2002 if ((code == TRUNC_DIV_EXPR
2003 || code == FLOOR_DIV_EXPR
2004 || code == CEIL_DIV_EXPR
2005 || code == EXACT_DIV_EXPR
2006 || code == ROUND_DIV_EXPR
2007 || code == RSHIFT_EXPR)
2008 && (is_overflow_infinity (val1)
2009 || is_overflow_infinity (val2)))
2012 /* Notice that we only need to handle the restricted set of
2013 operations handled by extract_range_from_binary_expr.
2014 Among them, only multiplication, addition and subtraction
2015 can yield overflow without overflown operands because we
2016 are working with integral types only... except in the
2017 case VAL1 = -INF and VAL2 = -1 which overflows to +INF
2018 for division too. */
2020 /* For multiplication, the sign of the overflow is given
2021 by the comparison of the signs of the operands. */
2022 if ((code == MULT_EXPR && sgn1 == sgn2)
2023 /* For addition, the operands must be of the same sign
2024 to yield an overflow. Its sign is therefore that
2025 of one of the operands, for example the first. For
2026 infinite operands X + -INF is negative, not positive. */
2027 || (code == PLUS_EXPR
2029 ? !is_negative_overflow_infinity (val2)
2030 : is_positive_overflow_infinity (val2)))
2031 /* For subtraction, non-infinite operands must be of
2032 different signs to yield an overflow. Its sign is
2033 therefore that of the first operand or the opposite of
2034 that of the second operand. A first operand of 0 counts
2035 as positive here, for the corner case 0 - (-INF), which
2036 overflows, but must yield +INF. For infinite operands 0
2037 - INF is negative, not positive. */
2038 || (code == MINUS_EXPR
2040 ? !is_positive_overflow_infinity (val2)
2041 : is_negative_overflow_infinity (val2)))
2042 /* We only get in here with positive shift count, so the
2043 overflow direction is the same as the sign of val1.
2044 Actually rshift does not overflow at all, but we only
2045 handle the case of shifting overflowed -INF and +INF. */
2046 || (code == RSHIFT_EXPR
2048 /* For division, the only case is -INF / -1 = +INF. */
2049 || code == TRUNC_DIV_EXPR
2050 || code == FLOOR_DIV_EXPR
2051 || code == CEIL_DIV_EXPR
2052 || code == EXACT_DIV_EXPR
2053 || code == ROUND_DIV_EXPR)
2054 return (needs_overflow_infinity (TREE_TYPE (res))
2055 ? positive_overflow_infinity (TREE_TYPE (res))
2056 : TYPE_MAX_VALUE (TREE_TYPE (res)));
2058 return (needs_overflow_infinity (TREE_TYPE (res))
2059 ? negative_overflow_infinity (TREE_TYPE (res))
2060 : TYPE_MIN_VALUE (TREE_TYPE (res)));
2067 /* Extract range information from a binary expression EXPR based on
2068 the ranges of each of its operands and the expression code. */
2071 extract_range_from_binary_expr (value_range_t *vr,
2072 enum tree_code code,
2073 tree expr_type, tree op0, tree op1)
2075 enum value_range_type type;
2078 value_range_t vr0 = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
2079 value_range_t vr1 = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
2081 /* Not all binary expressions can be applied to ranges in a
2082 meaningful way. Handle only arithmetic operations. */
2083 if (code != PLUS_EXPR
2084 && code != MINUS_EXPR
2085 && code != POINTER_PLUS_EXPR
2086 && code != MULT_EXPR
2087 && code != TRUNC_DIV_EXPR
2088 && code != FLOOR_DIV_EXPR
2089 && code != CEIL_DIV_EXPR
2090 && code != EXACT_DIV_EXPR
2091 && code != ROUND_DIV_EXPR
2092 && code != TRUNC_MOD_EXPR
2093 && code != RSHIFT_EXPR
2096 && code != BIT_AND_EXPR
2097 && code != BIT_IOR_EXPR
2098 && code != TRUTH_AND_EXPR
2099 && code != TRUTH_OR_EXPR)
2101 /* We can still do constant propagation here. */
2102 tree const_op0 = op_with_constant_singleton_value_range (op0);
2103 tree const_op1 = op_with_constant_singleton_value_range (op1);
2104 if (const_op0 || const_op1)
2106 tree tem = fold_binary (code, expr_type,
2107 const_op0 ? const_op0 : op0,
2108 const_op1 ? const_op1 : op1);
2110 && is_gimple_min_invariant (tem)
2111 && !is_overflow_infinity (tem))
2113 set_value_range (vr, VR_RANGE, tem, tem, NULL);
2117 set_value_range_to_varying (vr);
2121 /* Get value ranges for each operand. For constant operands, create
2122 a new value range with the operand to simplify processing. */
2123 if (TREE_CODE (op0) == SSA_NAME)
2124 vr0 = *(get_value_range (op0));
2125 else if (is_gimple_min_invariant (op0))
2126 set_value_range_to_value (&vr0, op0, NULL);
2128 set_value_range_to_varying (&vr0);
2130 if (TREE_CODE (op1) == SSA_NAME)
2131 vr1 = *(get_value_range (op1));
2132 else if (is_gimple_min_invariant (op1))
2133 set_value_range_to_value (&vr1, op1, NULL);
2135 set_value_range_to_varying (&vr1);
2137 /* If either range is UNDEFINED, so is the result. */
2138 if (vr0.type == VR_UNDEFINED || vr1.type == VR_UNDEFINED)
2140 set_value_range_to_undefined (vr);
2144 /* The type of the resulting value range defaults to VR0.TYPE. */
2147 /* Refuse to operate on VARYING ranges, ranges of different kinds
2148 and symbolic ranges. As an exception, we allow BIT_AND_EXPR
2149 because we may be able to derive a useful range even if one of
2150 the operands is VR_VARYING or symbolic range. Similarly for
2151 divisions. TODO, we may be able to derive anti-ranges in
2153 if (code != BIT_AND_EXPR
2154 && code != TRUTH_AND_EXPR
2155 && code != TRUTH_OR_EXPR
2156 && code != TRUNC_DIV_EXPR
2157 && code != FLOOR_DIV_EXPR
2158 && code != CEIL_DIV_EXPR
2159 && code != EXACT_DIV_EXPR
2160 && code != ROUND_DIV_EXPR
2161 && code != TRUNC_MOD_EXPR
2162 && (vr0.type == VR_VARYING
2163 || vr1.type == VR_VARYING
2164 || vr0.type != vr1.type
2165 || symbolic_range_p (&vr0)
2166 || symbolic_range_p (&vr1)))
2168 set_value_range_to_varying (vr);
2172 /* Now evaluate the expression to determine the new range. */
2173 if (POINTER_TYPE_P (expr_type)
2174 || POINTER_TYPE_P (TREE_TYPE (op0))
2175 || POINTER_TYPE_P (TREE_TYPE (op1)))
2177 if (code == MIN_EXPR || code == MAX_EXPR)
2179 /* For MIN/MAX expressions with pointers, we only care about
2180 nullness, if both are non null, then the result is nonnull.
2181 If both are null, then the result is null. Otherwise they
2183 if (range_is_nonnull (&vr0) && range_is_nonnull (&vr1))
2184 set_value_range_to_nonnull (vr, expr_type);
2185 else if (range_is_null (&vr0) && range_is_null (&vr1))
2186 set_value_range_to_null (vr, expr_type);
2188 set_value_range_to_varying (vr);
2192 if (code == POINTER_PLUS_EXPR)
2194 /* For pointer types, we are really only interested in asserting
2195 whether the expression evaluates to non-NULL. */
2196 if (range_is_nonnull (&vr0) || range_is_nonnull (&vr1))
2197 set_value_range_to_nonnull (vr, expr_type);
2198 else if (range_is_null (&vr0) && range_is_null (&vr1))
2199 set_value_range_to_null (vr, expr_type);
2201 set_value_range_to_varying (vr);
2203 else if (code == BIT_AND_EXPR)
2205 /* For pointer types, we are really only interested in asserting
2206 whether the expression evaluates to non-NULL. */
2207 if (range_is_nonnull (&vr0) && range_is_nonnull (&vr1))
2208 set_value_range_to_nonnull (vr, expr_type);
2209 else if (range_is_null (&vr0) || range_is_null (&vr1))
2210 set_value_range_to_null (vr, expr_type);
2212 set_value_range_to_varying (vr);
2220 /* For integer ranges, apply the operation to each end of the
2221 range and see what we end up with. */
2222 if (code == TRUTH_AND_EXPR
2223 || code == TRUTH_OR_EXPR)
2225 /* If one of the operands is zero, we know that the whole
2226 expression evaluates zero. */
2227 if (code == TRUTH_AND_EXPR
2228 && ((vr0.type == VR_RANGE
2229 && integer_zerop (vr0.min)
2230 && integer_zerop (vr0.max))
2231 || (vr1.type == VR_RANGE
2232 && integer_zerop (vr1.min)
2233 && integer_zerop (vr1.max))))
2236 min = max = build_int_cst (expr_type, 0);
2238 /* If one of the operands is one, we know that the whole
2239 expression evaluates one. */
2240 else if (code == TRUTH_OR_EXPR
2241 && ((vr0.type == VR_RANGE
2242 && integer_onep (vr0.min)
2243 && integer_onep (vr0.max))
2244 || (vr1.type == VR_RANGE
2245 && integer_onep (vr1.min)
2246 && integer_onep (vr1.max))))
2249 min = max = build_int_cst (expr_type, 1);
2251 else if (vr0.type != VR_VARYING
2252 && vr1.type != VR_VARYING
2253 && vr0.type == vr1.type
2254 && !symbolic_range_p (&vr0)
2255 && !overflow_infinity_range_p (&vr0)
2256 && !symbolic_range_p (&vr1)
2257 && !overflow_infinity_range_p (&vr1))
2259 /* Boolean expressions cannot be folded with int_const_binop. */
2260 min = fold_binary (code, expr_type, vr0.min, vr1.min);
2261 max = fold_binary (code, expr_type, vr0.max, vr1.max);
2265 /* The result of a TRUTH_*_EXPR is always true or false. */
2266 set_value_range_to_truthvalue (vr, expr_type);
2270 else if (code == PLUS_EXPR
2272 || code == MAX_EXPR)
2274 /* If we have a PLUS_EXPR with two VR_ANTI_RANGEs, drop to
2275 VR_VARYING. It would take more effort to compute a precise
2276 range for such a case. For example, if we have op0 == 1 and
2277 op1 == -1 with their ranges both being ~[0,0], we would have
2278 op0 + op1 == 0, so we cannot claim that the sum is in ~[0,0].
2279 Note that we are guaranteed to have vr0.type == vr1.type at
2281 if (code == PLUS_EXPR && vr0.type == VR_ANTI_RANGE)
2283 set_value_range_to_varying (vr);
2287 /* For operations that make the resulting range directly
2288 proportional to the original ranges, apply the operation to
2289 the same end of each range. */
2290 min = vrp_int_const_binop (code, vr0.min, vr1.min);
2291 max = vrp_int_const_binop (code, vr0.max, vr1.max);
2293 /* If both additions overflowed the range kind is still correct.
2294 This happens regularly with subtracting something in unsigned
2296 ??? See PR30318 for all the cases we do not handle. */
2297 if (code == PLUS_EXPR
2298 && (TREE_OVERFLOW (min) && !is_overflow_infinity (min))
2299 && (TREE_OVERFLOW (max) && !is_overflow_infinity (max)))
2301 min = build_int_cst_wide (TREE_TYPE (min),
2302 TREE_INT_CST_LOW (min),
2303 TREE_INT_CST_HIGH (min));
2304 max = build_int_cst_wide (TREE_TYPE (max),
2305 TREE_INT_CST_LOW (max),
2306 TREE_INT_CST_HIGH (max));
2309 else if (code == MULT_EXPR
2310 || code == TRUNC_DIV_EXPR
2311 || code == FLOOR_DIV_EXPR
2312 || code == CEIL_DIV_EXPR
2313 || code == EXACT_DIV_EXPR
2314 || code == ROUND_DIV_EXPR
2315 || code == RSHIFT_EXPR)
2321 /* If we have an unsigned MULT_EXPR with two VR_ANTI_RANGEs,
2322 drop to VR_VARYING. It would take more effort to compute a
2323 precise range for such a case. For example, if we have
2324 op0 == 65536 and op1 == 65536 with their ranges both being
2325 ~[0,0] on a 32-bit machine, we would have op0 * op1 == 0, so
2326 we cannot claim that the product is in ~[0,0]. Note that we
2327 are guaranteed to have vr0.type == vr1.type at this
2329 if (code == MULT_EXPR
2330 && vr0.type == VR_ANTI_RANGE
2331 && !TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (op0)))
2333 set_value_range_to_varying (vr);
2337 /* If we have a RSHIFT_EXPR with any shift values outside [0..prec-1],
2338 then drop to VR_VARYING. Outside of this range we get undefined
2339 behavior from the shift operation. We cannot even trust
2340 SHIFT_COUNT_TRUNCATED at this stage, because that applies to rtl
2341 shifts, and the operation at the tree level may be widened. */
2342 if (code == RSHIFT_EXPR)
2344 if (vr1.type == VR_ANTI_RANGE
2345 || !vrp_expr_computes_nonnegative (op1, &sop)
2347 (build_int_cst (TREE_TYPE (vr1.max),
2348 TYPE_PRECISION (expr_type) - 1),
2351 set_value_range_to_varying (vr);
2356 else if ((code == TRUNC_DIV_EXPR
2357 || code == FLOOR_DIV_EXPR
2358 || code == CEIL_DIV_EXPR
2359 || code == EXACT_DIV_EXPR
2360 || code == ROUND_DIV_EXPR)
2361 && (vr0.type != VR_RANGE || symbolic_range_p (&vr0)))
2363 /* For division, if op1 has VR_RANGE but op0 does not, something
2364 can be deduced just from that range. Say [min, max] / [4, max]
2365 gives [min / 4, max / 4] range. */
2366 if (vr1.type == VR_RANGE
2367 && !symbolic_range_p (&vr1)
2368 && !range_includes_zero_p (&vr1))
2370 vr0.type = type = VR_RANGE;
2371 vr0.min = vrp_val_min (TREE_TYPE (op0));
2372 vr0.max = vrp_val_max (TREE_TYPE (op1));
2376 set_value_range_to_varying (vr);
2381 /* For divisions, if op0 is VR_RANGE, we can deduce a range
2382 even if op1 is VR_VARYING, VR_ANTI_RANGE, symbolic or can
2384 if ((code == TRUNC_DIV_EXPR
2385 || code == FLOOR_DIV_EXPR
2386 || code == CEIL_DIV_EXPR
2387 || code == EXACT_DIV_EXPR
2388 || code == ROUND_DIV_EXPR)
2389 && vr0.type == VR_RANGE
2390 && (vr1.type != VR_RANGE
2391 || symbolic_range_p (&vr1)
2392 || range_includes_zero_p (&vr1)))
2394 tree zero = build_int_cst (TREE_TYPE (vr0.min), 0);
2400 if (vrp_expr_computes_nonnegative (op1, &sop) && !sop)
2402 /* For unsigned division or when divisor is known
2403 to be non-negative, the range has to cover
2404 all numbers from 0 to max for positive max
2405 and all numbers from min to 0 for negative min. */
2406 cmp = compare_values (vr0.max, zero);
2409 else if (cmp == 0 || cmp == 1)
2413 cmp = compare_values (vr0.min, zero);
2416 else if (cmp == 0 || cmp == -1)
2423 /* Otherwise the range is -max .. max or min .. -min
2424 depending on which bound is bigger in absolute value,
2425 as the division can change the sign. */
2426 abs_extent_range (vr, vr0.min, vr0.max);
2429 if (type == VR_VARYING)
2431 set_value_range_to_varying (vr);
2436 /* Multiplications and divisions are a bit tricky to handle,
2437 depending on the mix of signs we have in the two ranges, we
2438 need to operate on different values to get the minimum and
2439 maximum values for the new range. One approach is to figure
2440 out all the variations of range combinations and do the
2443 However, this involves several calls to compare_values and it
2444 is pretty convoluted. It's simpler to do the 4 operations
2445 (MIN0 OP MIN1, MIN0 OP MAX1, MAX0 OP MIN1 and MAX0 OP MAX0 OP
2446 MAX1) and then figure the smallest and largest values to form
2450 gcc_assert ((vr0.type == VR_RANGE
2451 || (code == MULT_EXPR && vr0.type == VR_ANTI_RANGE))
2452 && vr0.type == vr1.type);
2454 /* Compute the 4 cross operations. */
2456 val[0] = vrp_int_const_binop (code, vr0.min, vr1.min);
2457 if (val[0] == NULL_TREE)
2460 if (vr1.max == vr1.min)
2464 val[1] = vrp_int_const_binop (code, vr0.min, vr1.max);
2465 if (val[1] == NULL_TREE)
2469 if (vr0.max == vr0.min)
2473 val[2] = vrp_int_const_binop (code, vr0.max, vr1.min);
2474 if (val[2] == NULL_TREE)
2478 if (vr0.min == vr0.max || vr1.min == vr1.max)
2482 val[3] = vrp_int_const_binop (code, vr0.max, vr1.max);
2483 if (val[3] == NULL_TREE)
2489 set_value_range_to_varying (vr);
2493 /* Set MIN to the minimum of VAL[i] and MAX to the maximum
2497 for (i = 1; i < 4; i++)
2499 if (!is_gimple_min_invariant (min)
2500 || (TREE_OVERFLOW (min) && !is_overflow_infinity (min))
2501 || !is_gimple_min_invariant (max)
2502 || (TREE_OVERFLOW (max) && !is_overflow_infinity (max)))
2507 if (!is_gimple_min_invariant (val[i])
2508 || (TREE_OVERFLOW (val[i])
2509 && !is_overflow_infinity (val[i])))
2511 /* If we found an overflowed value, set MIN and MAX
2512 to it so that we set the resulting range to
2518 if (compare_values (val[i], min) == -1)
2521 if (compare_values (val[i], max) == 1)
2527 else if (code == TRUNC_MOD_EXPR)
2530 if (vr1.type != VR_RANGE
2531 || symbolic_range_p (&vr1)
2532 || range_includes_zero_p (&vr1)
2533 || vrp_val_is_min (vr1.min))
2535 set_value_range_to_varying (vr);
2539 /* Compute MAX <|vr1.min|, |vr1.max|> - 1. */
2540 max = fold_unary_to_constant (ABS_EXPR, TREE_TYPE (vr1.min), vr1.min);
2541 if (tree_int_cst_lt (max, vr1.max))
2543 max = int_const_binop (MINUS_EXPR, max, integer_one_node, 0);
2544 /* If the dividend is non-negative the modulus will be
2545 non-negative as well. */
2546 if (TYPE_UNSIGNED (TREE_TYPE (max))
2547 || (vrp_expr_computes_nonnegative (op0, &sop) && !sop))
2548 min = build_int_cst (TREE_TYPE (max), 0);
2550 min = fold_unary_to_constant (NEGATE_EXPR, TREE_TYPE (max), max);
2552 else if (code == MINUS_EXPR)
2554 /* If we have a MINUS_EXPR with two VR_ANTI_RANGEs, drop to
2555 VR_VARYING. It would take more effort to compute a precise
2556 range for such a case. For example, if we have op0 == 1 and
2557 op1 == 1 with their ranges both being ~[0,0], we would have
2558 op0 - op1 == 0, so we cannot claim that the difference is in
2559 ~[0,0]. Note that we are guaranteed to have
2560 vr0.type == vr1.type at this point. */
2561 if (vr0.type == VR_ANTI_RANGE)
2563 set_value_range_to_varying (vr);
2567 /* For MINUS_EXPR, apply the operation to the opposite ends of
2569 min = vrp_int_const_binop (code, vr0.min, vr1.max);
2570 max = vrp_int_const_binop (code, vr0.max, vr1.min);
2572 else if (code == BIT_AND_EXPR)
2574 bool vr0_int_cst_singleton_p, vr1_int_cst_singleton_p;
2576 vr0_int_cst_singleton_p = range_int_cst_singleton_p (&vr0);
2577 vr1_int_cst_singleton_p = range_int_cst_singleton_p (&vr1);
2579 if (vr0_int_cst_singleton_p && vr1_int_cst_singleton_p)
2580 min = max = int_const_binop (code, vr0.max, vr1.max, 0);
2581 else if (vr0_int_cst_singleton_p
2582 && tree_int_cst_sgn (vr0.max) >= 0)
2584 min = build_int_cst (expr_type, 0);
2587 else if (vr1_int_cst_singleton_p
2588 && tree_int_cst_sgn (vr1.max) >= 0)
2591 min = build_int_cst (expr_type, 0);
2596 set_value_range_to_varying (vr);
2600 else if (code == BIT_IOR_EXPR)
2602 if (range_int_cst_p (&vr0)
2603 && range_int_cst_p (&vr1)
2604 && tree_int_cst_sgn (vr0.min) >= 0
2605 && tree_int_cst_sgn (vr1.min) >= 0)
2607 double_int vr0_max = tree_to_double_int (vr0.max);
2608 double_int vr1_max = tree_to_double_int (vr1.max);
2611 /* Set all bits to the right of the most significant one to 1.
2612 For example, [0, 4] | [4, 4] = [4, 7]. */
2613 ior_max.low = vr0_max.low | vr1_max.low;
2614 ior_max.high = vr0_max.high | vr1_max.high;
2615 if (ior_max.high != 0)
2617 ior_max.low = ~(unsigned HOST_WIDE_INT)0u;
2618 ior_max.high |= ((HOST_WIDE_INT) 1
2619 << floor_log2 (ior_max.high)) - 1;
2621 else if (ior_max.low != 0)
2622 ior_max.low |= ((unsigned HOST_WIDE_INT) 1u
2623 << floor_log2 (ior_max.low)) - 1;
2625 /* Both of these endpoints are conservative. */
2626 min = vrp_int_const_binop (MAX_EXPR, vr0.min, vr1.min);
2627 max = double_int_to_tree (expr_type, ior_max);
2631 set_value_range_to_varying (vr);
2638 /* If either MIN or MAX overflowed, then set the resulting range to
2639 VARYING. But we do accept an overflow infinity
2641 if (min == NULL_TREE
2642 || !is_gimple_min_invariant (min)
2643 || (TREE_OVERFLOW (min) && !is_overflow_infinity (min))
2645 || !is_gimple_min_invariant (max)
2646 || (TREE_OVERFLOW (max) && !is_overflow_infinity (max)))
2648 set_value_range_to_varying (vr);
2654 2) [-INF, +-INF(OVF)]
2655 3) [+-INF(OVF), +INF]
2656 4) [+-INF(OVF), +-INF(OVF)]
2657 We learn nothing when we have INF and INF(OVF) on both sides.
2658 Note that we do accept [-INF, -INF] and [+INF, +INF] without
2660 if ((vrp_val_is_min (min) || is_overflow_infinity (min))
2661 && (vrp_val_is_max (max) || is_overflow_infinity (max)))
2663 set_value_range_to_varying (vr);
2667 cmp = compare_values (min, max);
2668 if (cmp == -2 || cmp == 1)
2670 /* If the new range has its limits swapped around (MIN > MAX),
2671 then the operation caused one of them to wrap around, mark
2672 the new range VARYING. */
2673 set_value_range_to_varying (vr);
2676 set_value_range (vr, type, min, max, NULL);
2680 /* Extract range information from a unary expression EXPR based on
2681 the range of its operand and the expression code. */
2684 extract_range_from_unary_expr (value_range_t *vr, enum tree_code code,
2685 tree type, tree op0)
2689 value_range_t vr0 = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
2691 /* Refuse to operate on certain unary expressions for which we
2692 cannot easily determine a resulting range. */
2693 if (code == FIX_TRUNC_EXPR
2694 || code == FLOAT_EXPR
2695 || code == BIT_NOT_EXPR
2696 || code == CONJ_EXPR)
2698 /* We can still do constant propagation here. */
2699 if ((op0 = op_with_constant_singleton_value_range (op0)) != NULL_TREE)
2701 tree tem = fold_unary (code, type, op0);
2703 && is_gimple_min_invariant (tem)
2704 && !is_overflow_infinity (tem))
2706 set_value_range (vr, VR_RANGE, tem, tem, NULL);
2710 set_value_range_to_varying (vr);
2714 /* Get value ranges for the operand. For constant operands, create
2715 a new value range with the operand to simplify processing. */
2716 if (TREE_CODE (op0) == SSA_NAME)
2717 vr0 = *(get_value_range (op0));
2718 else if (is_gimple_min_invariant (op0))
2719 set_value_range_to_value (&vr0, op0, NULL);
2721 set_value_range_to_varying (&vr0);
2723 /* If VR0 is UNDEFINED, so is the result. */
2724 if (vr0.type == VR_UNDEFINED)
2726 set_value_range_to_undefined (vr);
2730 /* Refuse to operate on symbolic ranges, or if neither operand is
2731 a pointer or integral type. */
2732 if ((!INTEGRAL_TYPE_P (TREE_TYPE (op0))
2733 && !POINTER_TYPE_P (TREE_TYPE (op0)))
2734 || (vr0.type != VR_VARYING
2735 && symbolic_range_p (&vr0)))
2737 set_value_range_to_varying (vr);
2741 /* If the expression involves pointers, we are only interested in
2742 determining if it evaluates to NULL [0, 0] or non-NULL (~[0, 0]). */
2743 if (POINTER_TYPE_P (type) || POINTER_TYPE_P (TREE_TYPE (op0)))
2748 if (range_is_nonnull (&vr0)
2749 || (tree_unary_nonzero_warnv_p (code, type, op0, &sop)
2751 set_value_range_to_nonnull (vr, type);
2752 else if (range_is_null (&vr0))
2753 set_value_range_to_null (vr, type);
2755 set_value_range_to_varying (vr);
2760 /* Handle unary expressions on integer ranges. */
2761 if (CONVERT_EXPR_CODE_P (code)
2762 && INTEGRAL_TYPE_P (type)
2763 && INTEGRAL_TYPE_P (TREE_TYPE (op0)))
2765 tree inner_type = TREE_TYPE (op0);
2766 tree outer_type = type;
2768 /* If VR0 is varying and we increase the type precision, assume
2769 a full range for the following transformation. */
2770 if (vr0.type == VR_VARYING
2771 && TYPE_PRECISION (inner_type) < TYPE_PRECISION (outer_type))
2773 vr0.type = VR_RANGE;
2774 vr0.min = TYPE_MIN_VALUE (inner_type);
2775 vr0.max = TYPE_MAX_VALUE (inner_type);
2778 /* If VR0 is a constant range or anti-range and the conversion is
2779 not truncating we can convert the min and max values and
2780 canonicalize the resulting range. Otherwise we can do the
2781 conversion if the size of the range is less than what the
2782 precision of the target type can represent and the range is
2783 not an anti-range. */
2784 if ((vr0.type == VR_RANGE
2785 || vr0.type == VR_ANTI_RANGE)
2786 && TREE_CODE (vr0.min) == INTEGER_CST
2787 && TREE_CODE (vr0.max) == INTEGER_CST
2788 && (!is_overflow_infinity (vr0.min)
2789 || (vr0.type == VR_RANGE
2790 && TYPE_PRECISION (outer_type) > TYPE_PRECISION (inner_type)
2791 && needs_overflow_infinity (outer_type)
2792 && supports_overflow_infinity (outer_type)))
2793 && (!is_overflow_infinity (vr0.max)
2794 || (vr0.type == VR_RANGE
2795 && TYPE_PRECISION (outer_type) > TYPE_PRECISION (inner_type)
2796 && needs_overflow_infinity (outer_type)
2797 && supports_overflow_infinity (outer_type)))
2798 && (TYPE_PRECISION (outer_type) >= TYPE_PRECISION (inner_type)
2799 || (vr0.type == VR_RANGE
2800 && integer_zerop (int_const_binop (RSHIFT_EXPR,
2801 int_const_binop (MINUS_EXPR, vr0.max, vr0.min, 0),
2802 size_int (TYPE_PRECISION (outer_type)), 0)))))
2804 tree new_min, new_max;
2805 new_min = force_fit_type_double (outer_type,
2806 tree_to_double_int (vr0.min),
2808 new_max = force_fit_type_double (outer_type,
2809 tree_to_double_int (vr0.max),
2811 if (is_overflow_infinity (vr0.min))
2812 new_min = negative_overflow_infinity (outer_type);
2813 if (is_overflow_infinity (vr0.max))
2814 new_max = positive_overflow_infinity (outer_type);
2815 set_and_canonicalize_value_range (vr, vr0.type,
2816 new_min, new_max, NULL);
2820 set_value_range_to_varying (vr);
2824 /* Conversion of a VR_VARYING value to a wider type can result
2825 in a usable range. So wait until after we've handled conversions
2826 before dropping the result to VR_VARYING if we had a source
2827 operand that is VR_VARYING. */
2828 if (vr0.type == VR_VARYING)
2830 set_value_range_to_varying (vr);
2834 /* Apply the operation to each end of the range and see what we end
2836 if (code == NEGATE_EXPR
2837 && !TYPE_UNSIGNED (type))
2839 /* NEGATE_EXPR flips the range around. We need to treat
2840 TYPE_MIN_VALUE specially. */
2841 if (is_positive_overflow_infinity (vr0.max))
2842 min = negative_overflow_infinity (type);
2843 else if (is_negative_overflow_infinity (vr0.max))
2844 min = positive_overflow_infinity (type);
2845 else if (!vrp_val_is_min (vr0.max))
2846 min = fold_unary_to_constant (code, type, vr0.max);
2847 else if (needs_overflow_infinity (type))
2849 if (supports_overflow_infinity (type)
2850 && !is_overflow_infinity (vr0.min)
2851 && !vrp_val_is_min (vr0.min))
2852 min = positive_overflow_infinity (type);
2855 set_value_range_to_varying (vr);
2860 min = TYPE_MIN_VALUE (type);
2862 if (is_positive_overflow_infinity (vr0.min))
2863 max = negative_overflow_infinity (type);
2864 else if (is_negative_overflow_infinity (vr0.min))
2865 max = positive_overflow_infinity (type);
2866 else if (!vrp_val_is_min (vr0.min))
2867 max = fold_unary_to_constant (code, type, vr0.min);
2868 else if (needs_overflow_infinity (type))
2870 if (supports_overflow_infinity (type))
2871 max = positive_overflow_infinity (type);
2874 set_value_range_to_varying (vr);
2879 max = TYPE_MIN_VALUE (type);
2881 else if (code == NEGATE_EXPR
2882 && TYPE_UNSIGNED (type))
2884 if (!range_includes_zero_p (&vr0))
2886 max = fold_unary_to_constant (code, type, vr0.min);
2887 min = fold_unary_to_constant (code, type, vr0.max);
2891 if (range_is_null (&vr0))
2892 set_value_range_to_null (vr, type);
2894 set_value_range_to_varying (vr);
2898 else if (code == ABS_EXPR
2899 && !TYPE_UNSIGNED (type))
2901 /* -TYPE_MIN_VALUE = TYPE_MIN_VALUE with flag_wrapv so we can't get a
2903 if (!TYPE_OVERFLOW_UNDEFINED (type)
2904 && ((vr0.type == VR_RANGE
2905 && vrp_val_is_min (vr0.min))
2906 || (vr0.type == VR_ANTI_RANGE
2907 && !vrp_val_is_min (vr0.min)
2908 && !range_includes_zero_p (&vr0))))
2910 set_value_range_to_varying (vr);
2914 /* ABS_EXPR may flip the range around, if the original range
2915 included negative values. */
2916 if (is_overflow_infinity (vr0.min))
2917 min = positive_overflow_infinity (type);
2918 else if (!vrp_val_is_min (vr0.min))
2919 min = fold_unary_to_constant (code, type, vr0.min);
2920 else if (!needs_overflow_infinity (type))
2921 min = TYPE_MAX_VALUE (type);
2922 else if (supports_overflow_infinity (type))
2923 min = positive_overflow_infinity (type);
2926 set_value_range_to_varying (vr);
2930 if (is_overflow_infinity (vr0.max))
2931 max = positive_overflow_infinity (type);
2932 else if (!vrp_val_is_min (vr0.max))
2933 max = fold_unary_to_constant (code, type, vr0.max);
2934 else if (!needs_overflow_infinity (type))
2935 max = TYPE_MAX_VALUE (type);
2936 else if (supports_overflow_infinity (type)
2937 /* We shouldn't generate [+INF, +INF] as set_value_range
2938 doesn't like this and ICEs. */
2939 && !is_positive_overflow_infinity (min))
2940 max = positive_overflow_infinity (type);
2943 set_value_range_to_varying (vr);
2947 cmp = compare_values (min, max);
2949 /* If a VR_ANTI_RANGEs contains zero, then we have
2950 ~[-INF, min(MIN, MAX)]. */
2951 if (vr0.type == VR_ANTI_RANGE)
2953 if (range_includes_zero_p (&vr0))
2955 /* Take the lower of the two values. */
2959 /* Create ~[-INF, min (abs(MIN), abs(MAX))]
2960 or ~[-INF + 1, min (abs(MIN), abs(MAX))] when
2961 flag_wrapv is set and the original anti-range doesn't include
2962 TYPE_MIN_VALUE, remember -TYPE_MIN_VALUE = TYPE_MIN_VALUE. */
2963 if (TYPE_OVERFLOW_WRAPS (type))
2965 tree type_min_value = TYPE_MIN_VALUE (type);
2967 min = (vr0.min != type_min_value
2968 ? int_const_binop (PLUS_EXPR, type_min_value,
2969 integer_one_node, 0)
2974 if (overflow_infinity_range_p (&vr0))
2975 min = negative_overflow_infinity (type);
2977 min = TYPE_MIN_VALUE (type);
2982 /* All else has failed, so create the range [0, INF], even for
2983 flag_wrapv since TYPE_MIN_VALUE is in the original
2985 vr0.type = VR_RANGE;
2986 min = build_int_cst (type, 0);
2987 if (needs_overflow_infinity (type))
2989 if (supports_overflow_infinity (type))
2990 max = positive_overflow_infinity (type);
2993 set_value_range_to_varying (vr);
2998 max = TYPE_MAX_VALUE (type);
3002 /* If the range contains zero then we know that the minimum value in the
3003 range will be zero. */
3004 else if (range_includes_zero_p (&vr0))
3008 min = build_int_cst (type, 0);
3012 /* If the range was reversed, swap MIN and MAX. */
3023 /* Otherwise, operate on each end of the range. */
3024 min = fold_unary_to_constant (code, type, vr0.min);
3025 max = fold_unary_to_constant (code, type, vr0.max);
3027 if (needs_overflow_infinity (type))
3029 gcc_assert (code != NEGATE_EXPR && code != ABS_EXPR);
3031 /* If both sides have overflowed, we don't know
3033 if ((is_overflow_infinity (vr0.min)
3034 || TREE_OVERFLOW (min))
3035 && (is_overflow_infinity (vr0.max)
3036 || TREE_OVERFLOW (max)))
3038 set_value_range_to_varying (vr);
3042 if (is_overflow_infinity (vr0.min))
3044 else if (TREE_OVERFLOW (min))
3046 if (supports_overflow_infinity (type))
3047 min = (tree_int_cst_sgn (min) >= 0
3048 ? positive_overflow_infinity (TREE_TYPE (min))
3049 : negative_overflow_infinity (TREE_TYPE (min)));
3052 set_value_range_to_varying (vr);
3057 if (is_overflow_infinity (vr0.max))
3059 else if (TREE_OVERFLOW (max))
3061 if (supports_overflow_infinity (type))
3062 max = (tree_int_cst_sgn (max) >= 0
3063 ? positive_overflow_infinity (TREE_TYPE (max))
3064 : negative_overflow_infinity (TREE_TYPE (max)));
3067 set_value_range_to_varying (vr);
3074 cmp = compare_values (min, max);
3075 if (cmp == -2 || cmp == 1)
3077 /* If the new range has its limits swapped around (MIN > MAX),
3078 then the operation caused one of them to wrap around, mark
3079 the new range VARYING. */
3080 set_value_range_to_varying (vr);
3083 set_value_range (vr, vr0.type, min, max, NULL);
3087 /* Extract range information from a conditional expression EXPR based on
3088 the ranges of each of its operands and the expression code. */
3091 extract_range_from_cond_expr (value_range_t *vr, tree expr)
3094 value_range_t vr0 = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
3095 value_range_t vr1 = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
3097 /* Get value ranges for each operand. For constant operands, create
3098 a new value range with the operand to simplify processing. */
3099 op0 = COND_EXPR_THEN (expr);
3100 if (TREE_CODE (op0) == SSA_NAME)
3101 vr0 = *(get_value_range (op0));
3102 else if (is_gimple_min_invariant (op0))
3103 set_value_range_to_value (&vr0, op0, NULL);
3105 set_value_range_to_varying (&vr0);
3107 op1 = COND_EXPR_ELSE (expr);
3108 if (TREE_CODE (op1) == SSA_NAME)
3109 vr1 = *(get_value_range (op1));
3110 else if (is_gimple_min_invariant (op1))
3111 set_value_range_to_value (&vr1, op1, NULL);
3113 set_value_range_to_varying (&vr1);
3115 /* The resulting value range is the union of the operand ranges */
3116 vrp_meet (&vr0, &vr1);
3117 copy_value_range (vr, &vr0);
3121 /* Extract range information from a comparison expression EXPR based
3122 on the range of its operand and the expression code. */
3125 extract_range_from_comparison (value_range_t *vr, enum tree_code code,
3126 tree type, tree op0, tree op1)
3131 val = vrp_evaluate_conditional_warnv_with_ops (code, op0, op1, false, &sop,
3134 /* A disadvantage of using a special infinity as an overflow
3135 representation is that we lose the ability to record overflow
3136 when we don't have an infinity. So we have to ignore a result
3137 which relies on overflow. */
3139 if (val && !is_overflow_infinity (val) && !sop)
3141 /* Since this expression was found on the RHS of an assignment,
3142 its type may be different from _Bool. Convert VAL to EXPR's
3144 val = fold_convert (type, val);
3145 if (is_gimple_min_invariant (val))
3146 set_value_range_to_value (vr, val, vr->equiv);
3148 set_value_range (vr, VR_RANGE, val, val, vr->equiv);
3151 /* The result of a comparison is always true or false. */
3152 set_value_range_to_truthvalue (vr, type);
3155 /* Try to derive a nonnegative or nonzero range out of STMT relying
3156 primarily on generic routines in fold in conjunction with range data.
3157 Store the result in *VR */
3160 extract_range_basic (value_range_t *vr, gimple stmt)
3163 tree type = gimple_expr_type (stmt);
3165 if (INTEGRAL_TYPE_P (type)
3166 && gimple_stmt_nonnegative_warnv_p (stmt, &sop))
3167 set_value_range_to_nonnegative (vr, type,
3168 sop || stmt_overflow_infinity (stmt));
3169 else if (vrp_stmt_computes_nonzero (stmt, &sop)
3171 set_value_range_to_nonnull (vr, type);
3173 set_value_range_to_varying (vr);
3177 /* Try to compute a useful range out of assignment STMT and store it
3181 extract_range_from_assignment (value_range_t *vr, gimple stmt)
3183 enum tree_code code = gimple_assign_rhs_code (stmt);
3185 if (code == ASSERT_EXPR)
3186 extract_range_from_assert (vr, gimple_assign_rhs1 (stmt));
3187 else if (code == SSA_NAME)
3188 extract_range_from_ssa_name (vr, gimple_assign_rhs1 (stmt));
3189 else if (TREE_CODE_CLASS (code) == tcc_binary
3190 || code == TRUTH_AND_EXPR
3191 || code == TRUTH_OR_EXPR
3192 || code == TRUTH_XOR_EXPR)
3193 extract_range_from_binary_expr (vr, gimple_assign_rhs_code (stmt),
3194 gimple_expr_type (stmt),
3195 gimple_assign_rhs1 (stmt),
3196 gimple_assign_rhs2 (stmt));
3197 else if (TREE_CODE_CLASS (code) == tcc_unary)
3198 extract_range_from_unary_expr (vr, gimple_assign_rhs_code (stmt),
3199 gimple_expr_type (stmt),
3200 gimple_assign_rhs1 (stmt));
3201 else if (code == COND_EXPR)
3202 extract_range_from_cond_expr (vr, gimple_assign_rhs1 (stmt));
3203 else if (TREE_CODE_CLASS (code) == tcc_comparison)
3204 extract_range_from_comparison (vr, gimple_assign_rhs_code (stmt),
3205 gimple_expr_type (stmt),
3206 gimple_assign_rhs1 (stmt),
3207 gimple_assign_rhs2 (stmt));
3208 else if (get_gimple_rhs_class (code) == GIMPLE_SINGLE_RHS
3209 && is_gimple_min_invariant (gimple_assign_rhs1 (stmt)))
3210 set_value_range_to_value (vr, gimple_assign_rhs1 (stmt), NULL);
3212 set_value_range_to_varying (vr);
3214 if (vr->type == VR_VARYING)
3215 extract_range_basic (vr, stmt);
3218 /* Given a range VR, a LOOP and a variable VAR, determine whether it
3219 would be profitable to adjust VR using scalar evolution information
3220 for VAR. If so, update VR with the new limits. */
3223 adjust_range_with_scev (value_range_t *vr, struct loop *loop,
3224 gimple stmt, tree var)
3226 tree init, step, chrec, tmin, tmax, min, max, type, tem;
3227 enum ev_direction dir;
3229 /* TODO. Don't adjust anti-ranges. An anti-range may provide
3230 better opportunities than a regular range, but I'm not sure. */
3231 if (vr->type == VR_ANTI_RANGE)
3234 chrec = instantiate_parameters (loop, analyze_scalar_evolution (loop, var));
3236 /* Like in PR19590, scev can return a constant function. */
3237 if (is_gimple_min_invariant (chrec))
3239 set_value_range_to_value (vr, chrec, vr->equiv);
3243 if (TREE_CODE (chrec) != POLYNOMIAL_CHREC)
3246 init = initial_condition_in_loop_num (chrec, loop->num);
3247 tem = op_with_constant_singleton_value_range (init);
3250 step = evolution_part_in_loop_num (chrec, loop->num);
3251 tem = op_with_constant_singleton_value_range (step);
3255 /* If STEP is symbolic, we can't know whether INIT will be the
3256 minimum or maximum value in the range. Also, unless INIT is
3257 a simple expression, compare_values and possibly other functions
3258 in tree-vrp won't be able to handle it. */
3259 if (step == NULL_TREE
3260 || !is_gimple_min_invariant (step)
3261 || !valid_value_p (init))
3264 dir = scev_direction (chrec);
3265 if (/* Do not adjust ranges if we do not know whether the iv increases
3266 or decreases, ... */
3267 dir == EV_DIR_UNKNOWN
3268 /* ... or if it may wrap. */
3269 || scev_probably_wraps_p (init, step, stmt, get_chrec_loop (chrec),
3273 /* We use TYPE_MIN_VALUE and TYPE_MAX_VALUE here instead of
3274 negative_overflow_infinity and positive_overflow_infinity,
3275 because we have concluded that the loop probably does not
3278 type = TREE_TYPE (var);
3279 if (POINTER_TYPE_P (type) || !TYPE_MIN_VALUE (type))
3280 tmin = lower_bound_in_type (type, type);
3282 tmin = TYPE_MIN_VALUE (type);
3283 if (POINTER_TYPE_P (type) || !TYPE_MAX_VALUE (type))
3284 tmax = upper_bound_in_type (type, type);
3286 tmax = TYPE_MAX_VALUE (type);
3288 if (vr->type == VR_VARYING || vr->type == VR_UNDEFINED)
3293 /* For VARYING or UNDEFINED ranges, just about anything we get
3294 from scalar evolutions should be better. */
3296 if (dir == EV_DIR_DECREASES)
3301 /* If we would create an invalid range, then just assume we
3302 know absolutely nothing. This may be over-conservative,
3303 but it's clearly safe, and should happen only in unreachable
3304 parts of code, or for invalid programs. */
3305 if (compare_values (min, max) == 1)
3308 set_value_range (vr, VR_RANGE, min, max, vr->equiv);
3310 else if (vr->type == VR_RANGE)
3315 if (dir == EV_DIR_DECREASES)
3317 /* INIT is the maximum value. If INIT is lower than VR->MAX
3318 but no smaller than VR->MIN, set VR->MAX to INIT. */
3319 if (compare_values (init, max) == -1)
3323 /* If we just created an invalid range with the minimum
3324 greater than the maximum, we fail conservatively.
3325 This should happen only in unreachable
3326 parts of code, or for invalid programs. */
3327 if (compare_values (min, max) == 1)
3331 /* According to the loop information, the variable does not
3332 overflow. If we think it does, probably because of an
3333 overflow due to arithmetic on a different INF value,
3335 if (is_negative_overflow_infinity (min))
3340 /* If INIT is bigger than VR->MIN, set VR->MIN to INIT. */
3341 if (compare_values (init, min) == 1)
3345 /* Again, avoid creating invalid range by failing. */
3346 if (compare_values (min, max) == 1)
3350 if (is_positive_overflow_infinity (max))
3354 set_value_range (vr, VR_RANGE, min, max, vr->equiv);
3358 /* Return true if VAR may overflow at STMT. This checks any available
3359 loop information to see if we can determine that VAR does not
3363 vrp_var_may_overflow (tree var, gimple stmt)
3366 tree chrec, init, step;
3368 if (current_loops == NULL)
3371 l = loop_containing_stmt (stmt);
3376 chrec = instantiate_parameters (l, analyze_scalar_evolution (l, var));
3377 if (TREE_CODE (chrec) != POLYNOMIAL_CHREC)
3380 init = initial_condition_in_loop_num (chrec, l->num);
3381 step = evolution_part_in_loop_num (chrec, l->num);
3383 if (step == NULL_TREE
3384 || !is_gimple_min_invariant (step)
3385 || !valid_value_p (init))
3388 /* If we get here, we know something useful about VAR based on the
3389 loop information. If it wraps, it may overflow. */
3391 if (scev_probably_wraps_p (init, step, stmt, get_chrec_loop (chrec),
3395 if (dump_file && (dump_flags & TDF_DETAILS) != 0)
3397 print_generic_expr (dump_file, var, 0);
3398 fprintf (dump_file, ": loop information indicates does not overflow\n");
3405 /* Given two numeric value ranges VR0, VR1 and a comparison code COMP:
3407 - Return BOOLEAN_TRUE_NODE if VR0 COMP VR1 always returns true for
3408 all the values in the ranges.
3410 - Return BOOLEAN_FALSE_NODE if the comparison always returns false.
3412 - Return NULL_TREE if it is not always possible to determine the
3413 value of the comparison.
3415 Also set *STRICT_OVERFLOW_P to indicate whether a range with an
3416 overflow infinity was used in the test. */
3420 compare_ranges (enum tree_code comp, value_range_t *vr0, value_range_t *vr1,
3421 bool *strict_overflow_p)
3423 /* VARYING or UNDEFINED ranges cannot be compared. */
3424 if (vr0->type == VR_VARYING
3425 || vr0->type == VR_UNDEFINED
3426 || vr1->type == VR_VARYING
3427 || vr1->type == VR_UNDEFINED)
3430 /* Anti-ranges need to be handled separately. */
3431 if (vr0->type == VR_ANTI_RANGE || vr1->type == VR_ANTI_RANGE)
3433 /* If both are anti-ranges, then we cannot compute any
3435 if (vr0->type == VR_ANTI_RANGE && vr1->type == VR_ANTI_RANGE)
3438 /* These comparisons are never statically computable. */
3445 /* Equality can be computed only between a range and an
3446 anti-range. ~[VAL1, VAL2] == [VAL1, VAL2] is always false. */
3447 if (vr0->type == VR_RANGE)
3449 /* To simplify processing, make VR0 the anti-range. */
3450 value_range_t *tmp = vr0;
3455 gcc_assert (comp == NE_EXPR || comp == EQ_EXPR);
3457 if (compare_values_warnv (vr0->min, vr1->min, strict_overflow_p) == 0
3458 && compare_values_warnv (vr0->max, vr1->max, strict_overflow_p) == 0)
3459 return (comp == NE_EXPR) ? boolean_true_node : boolean_false_node;
3464 if (!usable_range_p (vr0, strict_overflow_p)
3465 || !usable_range_p (vr1, strict_overflow_p))
3468 /* Simplify processing. If COMP is GT_EXPR or GE_EXPR, switch the
3469 operands around and change the comparison code. */
3470 if (comp == GT_EXPR || comp == GE_EXPR)
3473 comp = (comp == GT_EXPR) ? LT_EXPR : LE_EXPR;
3479 if (comp == EQ_EXPR)
3481 /* Equality may only be computed if both ranges represent
3482 exactly one value. */
3483 if (compare_values_warnv (vr0->min, vr0->max, strict_overflow_p) == 0
3484 && compare_values_warnv (vr1->min, vr1->max, strict_overflow_p) == 0)
3486 int cmp_min = compare_values_warnv (vr0->min, vr1->min,
3488 int cmp_max = compare_values_warnv (vr0->max, vr1->max,
3490 if (cmp_min == 0 && cmp_max == 0)
3491 return boolean_true_node;
3492 else if (cmp_min != -2 && cmp_max != -2)
3493 return boolean_false_node;
3495 /* If [V0_MIN, V1_MAX] < [V1_MIN, V1_MAX] then V0 != V1. */
3496 else if (compare_values_warnv (vr0->min, vr1->max,
3497 strict_overflow_p) == 1
3498 || compare_values_warnv (vr1->min, vr0->max,
3499 strict_overflow_p) == 1)
3500 return boolean_false_node;
3504 else if (comp == NE_EXPR)
3508 /* If VR0 is completely to the left or completely to the right
3509 of VR1, they are always different. Notice that we need to
3510 make sure that both comparisons yield similar results to
3511 avoid comparing values that cannot be compared at
3513 cmp1 = compare_values_warnv (vr0->max, vr1->min, strict_overflow_p);
3514 cmp2 = compare_values_warnv (vr0->min, vr1->max, strict_overflow_p);
3515 if ((cmp1 == -1 && cmp2 == -1) || (cmp1 == 1 && cmp2 == 1))
3516 return boolean_true_node;
3518 /* If VR0 and VR1 represent a single value and are identical,
3520 else if (compare_values_warnv (vr0->min, vr0->max,
3521 strict_overflow_p) == 0
3522 && compare_values_warnv (vr1->min, vr1->max,
3523 strict_overflow_p) == 0
3524 && compare_values_warnv (vr0->min, vr1->min,
3525 strict_overflow_p) == 0
3526 && compare_values_warnv (vr0->max, vr1->max,
3527 strict_overflow_p) == 0)
3528 return boolean_false_node;
3530 /* Otherwise, they may or may not be different. */
3534 else if (comp == LT_EXPR || comp == LE_EXPR)
3538 /* If VR0 is to the left of VR1, return true. */
3539 tst = compare_values_warnv (vr0->max, vr1->min, strict_overflow_p);
3540 if ((comp == LT_EXPR && tst == -1)
3541 || (comp == LE_EXPR && (tst == -1 || tst == 0)))
3543 if (overflow_infinity_range_p (vr0)
3544 || overflow_infinity_range_p (vr1))
3545 *strict_overflow_p = true;
3546 return boolean_true_node;
3549 /* If VR0 is to the right of VR1, return false. */
3550 tst = compare_values_warnv (vr0->min, vr1->max, strict_overflow_p);
3551 if ((comp == LT_EXPR && (tst == 0 || tst == 1))
3552 || (comp == LE_EXPR && tst == 1))
3554 if (overflow_infinity_range_p (vr0)
3555 || overflow_infinity_range_p (vr1))
3556 *strict_overflow_p = true;
3557 return boolean_false_node;
3560 /* Otherwise, we don't know. */
3568 /* Given a value range VR, a value VAL and a comparison code COMP, return
3569 BOOLEAN_TRUE_NODE if VR COMP VAL always returns true for all the
3570 values in VR. Return BOOLEAN_FALSE_NODE if the comparison
3571 always returns false. Return NULL_TREE if it is not always
3572 possible to determine the value of the comparison. Also set
3573 *STRICT_OVERFLOW_P to indicate whether a range with an overflow
3574 infinity was used in the test. */
3577 compare_range_with_value (enum tree_code comp, value_range_t *vr, tree val,
3578 bool *strict_overflow_p)
3580 if (vr->type == VR_VARYING || vr->type == VR_UNDEFINED)
3583 /* Anti-ranges need to be handled separately. */
3584 if (vr->type == VR_ANTI_RANGE)
3586 /* For anti-ranges, the only predicates that we can compute at
3587 compile time are equality and inequality. */
3594 /* ~[VAL_1, VAL_2] OP VAL is known if VAL_1 <= VAL <= VAL_2. */
3595 if (value_inside_range (val, vr) == 1)
3596 return (comp == NE_EXPR) ? boolean_true_node : boolean_false_node;
3601 if (!usable_range_p (vr, strict_overflow_p))
3604 if (comp == EQ_EXPR)
3606 /* EQ_EXPR may only be computed if VR represents exactly
3608 if (compare_values_warnv (vr->min, vr->max, strict_overflow_p) == 0)
3610 int cmp = compare_values_warnv (vr->min, val, strict_overflow_p);
3612 return boolean_true_node;
3613 else if (cmp == -1 || cmp == 1 || cmp == 2)
3614 return boolean_false_node;
3616 else if (compare_values_warnv (val, vr->min, strict_overflow_p) == -1
3617 || compare_values_warnv (vr->max, val, strict_overflow_p) == -1)
3618 return boolean_false_node;
3622 else if (comp == NE_EXPR)
3624 /* If VAL is not inside VR, then they are always different. */
3625 if (compare_values_warnv (vr->max, val, strict_overflow_p) == -1
3626 || compare_values_warnv (vr->min, val, strict_overflow_p) == 1)
3627 return boolean_true_node;
3629 /* If VR represents exactly one value equal to VAL, then return
3631 if (compare_values_warnv (vr->min, vr->max, strict_overflow_p) == 0
3632 && compare_values_warnv (vr->min, val, strict_overflow_p) == 0)
3633 return boolean_false_node;
3635 /* Otherwise, they may or may not be different. */
3638 else if (comp == LT_EXPR || comp == LE_EXPR)
3642 /* If VR is to the left of VAL, return true. */
3643 tst = compare_values_warnv (vr->max, val, strict_overflow_p);
3644 if ((comp == LT_EXPR && tst == -1)
3645 || (comp == LE_EXPR && (tst == -1 || tst == 0)))
3647 if (overflow_infinity_range_p (vr))
3648 *strict_overflow_p = true;
3649 return boolean_true_node;
3652 /* If VR is to the right of VAL, return false. */
3653 tst = compare_values_warnv (vr->min, val, strict_overflow_p);
3654 if ((comp == LT_EXPR && (tst == 0 || tst == 1))
3655 || (comp == LE_EXPR && tst == 1))
3657 if (overflow_infinity_range_p (vr))
3658 *strict_overflow_p = true;
3659 return boolean_false_node;
3662 /* Otherwise, we don't know. */
3665 else if (comp == GT_EXPR || comp == GE_EXPR)
3669 /* If VR is to the right of VAL, return true. */
3670 tst = compare_values_warnv (vr->min, val, strict_overflow_p);
3671 if ((comp == GT_EXPR && tst == 1)
3672 || (comp == GE_EXPR && (tst == 0 || tst == 1)))
3674 if (overflow_infinity_range_p (vr))
3675 *strict_overflow_p = true;
3676 return boolean_true_node;
3679 /* If VR is to the left of VAL, return false. */
3680 tst = compare_values_warnv (vr->max, val, strict_overflow_p);
3681 if ((comp == GT_EXPR && (tst == -1 || tst == 0))
3682 || (comp == GE_EXPR && tst == -1))
3684 if (overflow_infinity_range_p (vr))
3685 *strict_overflow_p = true;
3686 return boolean_false_node;
3689 /* Otherwise, we don't know. */
3697 /* Debugging dumps. */
3699 void dump_value_range (FILE *, value_range_t *);
3700 void debug_value_range (value_range_t *);
3701 void dump_all_value_ranges (FILE *);
3702 void debug_all_value_ranges (void);
3703 void dump_vr_equiv (FILE *, bitmap);
3704 void debug_vr_equiv (bitmap);
3707 /* Dump value range VR to FILE. */
3710 dump_value_range (FILE *file, value_range_t *vr)
3713 fprintf (file, "[]");
3714 else if (vr->type == VR_UNDEFINED)
3715 fprintf (file, "UNDEFINED");
3716 else if (vr->type == VR_RANGE || vr->type == VR_ANTI_RANGE)
3718 tree type = TREE_TYPE (vr->min);
3720 fprintf (file, "%s[", (vr->type == VR_ANTI_RANGE) ? "~" : "");
3722 if (is_negative_overflow_infinity (vr->min))
3723 fprintf (file, "-INF(OVF)");
3724 else if (INTEGRAL_TYPE_P (type)
3725 && !TYPE_UNSIGNED (type)
3726 && vrp_val_is_min (vr->min))
3727 fprintf (file, "-INF");
3729 print_generic_expr (file, vr->min, 0);
3731 fprintf (file, ", ");
3733 if (is_positive_overflow_infinity (vr->max))
3734 fprintf (file, "+INF(OVF)");
3735 else if (INTEGRAL_TYPE_P (type)
3736 && vrp_val_is_max (vr->max))
3737 fprintf (file, "+INF");
3739 print_generic_expr (file, vr->max, 0);
3741 fprintf (file, "]");
3748 fprintf (file, " EQUIVALENCES: { ");
3750 EXECUTE_IF_SET_IN_BITMAP (vr->equiv, 0, i, bi)
3752 print_generic_expr (file, ssa_name (i), 0);
3753 fprintf (file, " ");
3757 fprintf (file, "} (%u elements)", c);
3760 else if (vr->type == VR_VARYING)
3761 fprintf (file, "VARYING");
3763 fprintf (file, "INVALID RANGE");
3767 /* Dump value range VR to stderr. */
3770 debug_value_range (value_range_t *vr)
3772 dump_value_range (stderr, vr);
3773 fprintf (stderr, "\n");
3777 /* Dump value ranges of all SSA_NAMEs to FILE. */
3780 dump_all_value_ranges (FILE *file)
3784 for (i = 0; i < num_ssa_names; i++)
3788 print_generic_expr (file, ssa_name (i), 0);
3789 fprintf (file, ": ");
3790 dump_value_range (file, vr_value[i]);
3791 fprintf (file, "\n");
3795 fprintf (file, "\n");
3799 /* Dump all value ranges to stderr. */
3802 debug_all_value_ranges (void)
3804 dump_all_value_ranges (stderr);
3808 /* Given a COND_EXPR COND of the form 'V OP W', and an SSA name V,
3809 create a new SSA name N and return the assertion assignment
3810 'V = ASSERT_EXPR <V, V OP W>'. */
3813 build_assert_expr_for (tree cond, tree v)
3818 gcc_assert (TREE_CODE (v) == SSA_NAME);
3819 n = duplicate_ssa_name (v, NULL);
3821 if (COMPARISON_CLASS_P (cond))
3823 tree a = build2 (ASSERT_EXPR, TREE_TYPE (v), v, cond);
3824 assertion = gimple_build_assign (n, a);
3826 else if (TREE_CODE (cond) == TRUTH_NOT_EXPR)
3828 /* Given !V, build the assignment N = false. */
3829 tree op0 = TREE_OPERAND (cond, 0);
3830 gcc_assert (op0 == v);
3831 assertion = gimple_build_assign (n, boolean_false_node);
3833 else if (TREE_CODE (cond) == SSA_NAME)
3835 /* Given V, build the assignment N = true. */
3836 gcc_assert (v == cond);
3837 assertion = gimple_build_assign (n, boolean_true_node);
3842 SSA_NAME_DEF_STMT (n) = assertion;
3844 /* The new ASSERT_EXPR, creates a new SSA name that replaces the
3845 operand of the ASSERT_EXPR. Register the new name and the old one
3846 in the replacement table so that we can fix the SSA web after
3847 adding all the ASSERT_EXPRs. */
3848 register_new_name_mapping (n, v);
3854 /* Return false if EXPR is a predicate expression involving floating
3858 fp_predicate (gimple stmt)
3860 GIMPLE_CHECK (stmt, GIMPLE_COND);
3862 return FLOAT_TYPE_P (TREE_TYPE (gimple_cond_lhs (stmt)));
3866 /* If the range of values taken by OP can be inferred after STMT executes,
3867 return the comparison code (COMP_CODE_P) and value (VAL_P) that
3868 describes the inferred range. Return true if a range could be
3872 infer_value_range (gimple stmt, tree op, enum tree_code *comp_code_p, tree *val_p)
3875 *comp_code_p = ERROR_MARK;
3877 /* Do not attempt to infer anything in names that flow through
3879 if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (op))
3882 /* Similarly, don't infer anything from statements that may throw
3884 if (stmt_could_throw_p (stmt))
3887 /* If STMT is the last statement of a basic block with no
3888 successors, there is no point inferring anything about any of its
3889 operands. We would not be able to find a proper insertion point
3890 for the assertion, anyway. */
3891 if (stmt_ends_bb_p (stmt) && EDGE_COUNT (gimple_bb (stmt)->succs) == 0)
3894 /* We can only assume that a pointer dereference will yield
3895 non-NULL if -fdelete-null-pointer-checks is enabled. */
3896 if (flag_delete_null_pointer_checks
3897 && POINTER_TYPE_P (TREE_TYPE (op))
3898 && gimple_code (stmt) != GIMPLE_ASM)
3900 unsigned num_uses, num_loads, num_stores;
3902 count_uses_and_derefs (op, stmt, &num_uses, &num_loads, &num_stores);
3903 if (num_loads + num_stores > 0)
3905 *val_p = build_int_cst (TREE_TYPE (op), 0);
3906 *comp_code_p = NE_EXPR;
3915 void dump_asserts_for (FILE *, tree);
3916 void debug_asserts_for (tree);
3917 void dump_all_asserts (FILE *);
3918 void debug_all_asserts (void);
3920 /* Dump all the registered assertions for NAME to FILE. */
3923 dump_asserts_for (FILE *file, tree name)
3927 fprintf (file, "Assertions to be inserted for ");
3928 print_generic_expr (file, name, 0);
3929 fprintf (file, "\n");
3931 loc = asserts_for[SSA_NAME_VERSION (name)];
3934 fprintf (file, "\t");
3935 print_gimple_stmt (file, gsi_stmt (loc->si), 0, 0);
3936 fprintf (file, "\n\tBB #%d", loc->bb->index);
3939 fprintf (file, "\n\tEDGE %d->%d", loc->e->src->index,
3940 loc->e->dest->index);
3941 dump_edge_info (file, loc->e, 0);
3943 fprintf (file, "\n\tPREDICATE: ");
3944 print_generic_expr (file, name, 0);
3945 fprintf (file, " %s ", tree_code_name[(int)loc->comp_code]);
3946 print_generic_expr (file, loc->val, 0);
3947 fprintf (file, "\n\n");
3951 fprintf (file, "\n");
3955 /* Dump all the registered assertions for NAME to stderr. */
3958 debug_asserts_for (tree name)
3960 dump_asserts_for (stderr, name);
3964 /* Dump all the registered assertions for all the names to FILE. */
3967 dump_all_asserts (FILE *file)
3972 fprintf (file, "\nASSERT_EXPRs to be inserted\n\n");
3973 EXECUTE_IF_SET_IN_BITMAP (need_assert_for, 0, i, bi)
3974 dump_asserts_for (file, ssa_name (i));
3975 fprintf (file, "\n");
3979 /* Dump all the registered assertions for all the names to stderr. */
3982 debug_all_asserts (void)
3984 dump_all_asserts (stderr);
3988 /* If NAME doesn't have an ASSERT_EXPR registered for asserting
3989 'EXPR COMP_CODE VAL' at a location that dominates block BB or
3990 E->DEST, then register this location as a possible insertion point
3991 for ASSERT_EXPR <NAME, EXPR COMP_CODE VAL>.
3993 BB, E and SI provide the exact insertion point for the new
3994 ASSERT_EXPR. If BB is NULL, then the ASSERT_EXPR is to be inserted
3995 on edge E. Otherwise, if E is NULL, the ASSERT_EXPR is inserted on
3996 BB. If SI points to a COND_EXPR or a SWITCH_EXPR statement, then E
3997 must not be NULL. */
4000 register_new_assert_for (tree name, tree expr,
4001 enum tree_code comp_code,
4005 gimple_stmt_iterator si)
4007 assert_locus_t n, loc, last_loc;
4008 basic_block dest_bb;
4010 #if defined ENABLE_CHECKING
4011 gcc_assert (bb == NULL || e == NULL);
4014 gcc_assert (gimple_code (gsi_stmt (si)) != GIMPLE_COND
4015 && gimple_code (gsi_stmt (si)) != GIMPLE_SWITCH);
4018 /* Never build an assert comparing against an integer constant with
4019 TREE_OVERFLOW set. This confuses our undefined overflow warning
4021 if (TREE_CODE (val) == INTEGER_CST
4022 && TREE_OVERFLOW (val))
4023 val = build_int_cst_wide (TREE_TYPE (val),
4024 TREE_INT_CST_LOW (val), TREE_INT_CST_HIGH (val));
4026 /* The new assertion A will be inserted at BB or E. We need to
4027 determine if the new location is dominated by a previously
4028 registered location for A. If we are doing an edge insertion,
4029 assume that A will be inserted at E->DEST. Note that this is not
4032 If E is a critical edge, it will be split. But even if E is
4033 split, the new block will dominate the same set of blocks that
4036 The reverse, however, is not true, blocks dominated by E->DEST
4037 will not be dominated by the new block created to split E. So,
4038 if the insertion location is on a critical edge, we will not use
4039 the new location to move another assertion previously registered
4040 at a block dominated by E->DEST. */
4041 dest_bb = (bb) ? bb : e->dest;
4043 /* If NAME already has an ASSERT_EXPR registered for COMP_CODE and
4044 VAL at a block dominating DEST_BB, then we don't need to insert a new
4045 one. Similarly, if the same assertion already exists at a block
4046 dominated by DEST_BB and the new location is not on a critical
4047 edge, then update the existing location for the assertion (i.e.,
4048 move the assertion up in the dominance tree).
4050 Note, this is implemented as a simple linked list because there
4051 should not be more than a handful of assertions registered per
4052 name. If this becomes a performance problem, a table hashed by
4053 COMP_CODE and VAL could be implemented. */
4054 loc = asserts_for[SSA_NAME_VERSION (name)];
4058 if (loc->comp_code == comp_code
4060 || operand_equal_p (loc->val, val, 0))
4061 && (loc->expr == expr
4062 || operand_equal_p (loc->expr, expr, 0)))
4064 /* If the assertion NAME COMP_CODE VAL has already been
4065 registered at a basic block that dominates DEST_BB, then
4066 we don't need to insert the same assertion again. Note
4067 that we don't check strict dominance here to avoid
4068 replicating the same assertion inside the same basic
4069 block more than once (e.g., when a pointer is
4070 dereferenced several times inside a block).
4072 An exception to this rule are edge insertions. If the
4073 new assertion is to be inserted on edge E, then it will
4074 dominate all the other insertions that we may want to
4075 insert in DEST_BB. So, if we are doing an edge
4076 insertion, don't do this dominance check. */
4078 && dominated_by_p (CDI_DOMINATORS, dest_bb, loc->bb))
4081 /* Otherwise, if E is not a critical edge and DEST_BB
4082 dominates the existing location for the assertion, move
4083 the assertion up in the dominance tree by updating its
4084 location information. */
4085 if ((e == NULL || !EDGE_CRITICAL_P (e))
4086 && dominated_by_p (CDI_DOMINATORS, loc->bb, dest_bb))
4095 /* Update the last node of the list and move to the next one. */
4100 /* If we didn't find an assertion already registered for
4101 NAME COMP_CODE VAL, add a new one at the end of the list of
4102 assertions associated with NAME. */
4103 n = XNEW (struct assert_locus_d);
4107 n->comp_code = comp_code;
4115 asserts_for[SSA_NAME_VERSION (name)] = n;
4117 bitmap_set_bit (need_assert_for, SSA_NAME_VERSION (name));
4120 /* (COND_OP0 COND_CODE COND_OP1) is a predicate which uses NAME.
4121 Extract a suitable test code and value and store them into *CODE_P and
4122 *VAL_P so the predicate is normalized to NAME *CODE_P *VAL_P.
4124 If no extraction was possible, return FALSE, otherwise return TRUE.
4126 If INVERT is true, then we invert the result stored into *CODE_P. */
4129 extract_code_and_val_from_cond_with_ops (tree name, enum tree_code cond_code,
4130 tree cond_op0, tree cond_op1,
4131 bool invert, enum tree_code *code_p,
4134 enum tree_code comp_code;
4137 /* Otherwise, we have a comparison of the form NAME COMP VAL
4138 or VAL COMP NAME. */
4139 if (name == cond_op1)
4141 /* If the predicate is of the form VAL COMP NAME, flip
4142 COMP around because we need to register NAME as the
4143 first operand in the predicate. */
4144 comp_code = swap_tree_comparison (cond_code);
4149 /* The comparison is of the form NAME COMP VAL, so the
4150 comparison code remains unchanged. */
4151 comp_code = cond_code;
4155 /* Invert the comparison code as necessary. */
4157 comp_code = invert_tree_comparison (comp_code, 0);
4159 /* VRP does not handle float types. */
4160 if (SCALAR_FLOAT_TYPE_P (TREE_TYPE (val)))
4163 /* Do not register always-false predicates.
4164 FIXME: this works around a limitation in fold() when dealing with
4165 enumerations. Given 'enum { N1, N2 } x;', fold will not
4166 fold 'if (x > N2)' to 'if (0)'. */
4167 if ((comp_code == GT_EXPR || comp_code == LT_EXPR)
4168 && INTEGRAL_TYPE_P (TREE_TYPE (val)))
4170 tree min = TYPE_MIN_VALUE (TREE_TYPE (val));
4171 tree max = TYPE_MAX_VALUE (TREE_TYPE (val));
4173 if (comp_code == GT_EXPR
4175 || compare_values (val, max) == 0))
4178 if (comp_code == LT_EXPR
4180 || compare_values (val, min) == 0))
4183 *code_p = comp_code;
4188 /* Try to register an edge assertion for SSA name NAME on edge E for
4189 the condition COND contributing to the conditional jump pointed to by BSI.
4190 Invert the condition COND if INVERT is true.
4191 Return true if an assertion for NAME could be registered. */
4194 register_edge_assert_for_2 (tree name, edge e, gimple_stmt_iterator bsi,
4195 enum tree_code cond_code,
4196 tree cond_op0, tree cond_op1, bool invert)
4199 enum tree_code comp_code;
4200 bool retval = false;
4202 if (!extract_code_and_val_from_cond_with_ops (name, cond_code,
4205 invert, &comp_code, &val))
4208 /* Only register an ASSERT_EXPR if NAME was found in the sub-graph
4209 reachable from E. */
4210 if (live_on_edge (e, name)
4211 && !has_single_use (name))
4213 register_new_assert_for (name, name, comp_code, val, NULL, e, bsi);
4217 /* In the case of NAME <= CST and NAME being defined as
4218 NAME = (unsigned) NAME2 + CST2 we can assert NAME2 >= -CST2
4219 and NAME2 <= CST - CST2. We can do the same for NAME > CST.
4220 This catches range and anti-range tests. */
4221 if ((comp_code == LE_EXPR
4222 || comp_code == GT_EXPR)
4223 && TREE_CODE (val) == INTEGER_CST
4224 && TYPE_UNSIGNED (TREE_TYPE (val)))
4226 gimple def_stmt = SSA_NAME_DEF_STMT (name);
4227 tree cst2 = NULL_TREE, name2 = NULL_TREE, name3 = NULL_TREE;
4229 /* Extract CST2 from the (optional) addition. */
4230 if (is_gimple_assign (def_stmt)
4231 && gimple_assign_rhs_code (def_stmt) == PLUS_EXPR)
4233 name2 = gimple_assign_rhs1 (def_stmt);
4234 cst2 = gimple_assign_rhs2 (def_stmt);
4235 if (TREE_CODE (name2) == SSA_NAME
4236 && TREE_CODE (cst2) == INTEGER_CST)
4237 def_stmt = SSA_NAME_DEF_STMT (name2);
4240 /* Extract NAME2 from the (optional) sign-changing cast. */
4241 if (gimple_assign_cast_p (def_stmt))
4243 if (CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (def_stmt))
4244 && ! TYPE_UNSIGNED (TREE_TYPE (gimple_assign_rhs1 (def_stmt)))
4245 && (TYPE_PRECISION (gimple_expr_type (def_stmt))
4246 == TYPE_PRECISION (TREE_TYPE (gimple_assign_rhs1 (def_stmt)))))
4247 name3 = gimple_assign_rhs1 (def_stmt);
4250 /* If name3 is used later, create an ASSERT_EXPR for it. */
4251 if (name3 != NULL_TREE
4252 && TREE_CODE (name3) == SSA_NAME
4253 && (cst2 == NULL_TREE
4254 || TREE_CODE (cst2) == INTEGER_CST)
4255 && INTEGRAL_TYPE_P (TREE_TYPE (name3))
4256 && live_on_edge (e, name3)
4257 && !has_single_use (name3))
4261 /* Build an expression for the range test. */
4262 tmp = build1 (NOP_EXPR, TREE_TYPE (name), name3);
4263 if (cst2 != NULL_TREE)
4264 tmp = build2 (PLUS_EXPR, TREE_TYPE (name), tmp, cst2);
4268 fprintf (dump_file, "Adding assert for ");
4269 print_generic_expr (dump_file, name3, 0);
4270 fprintf (dump_file, " from ");
4271 print_generic_expr (dump_file, tmp, 0);
4272 fprintf (dump_file, "\n");
4275 register_new_assert_for (name3, tmp, comp_code, val, NULL, e, bsi);
4280 /* If name2 is used later, create an ASSERT_EXPR for it. */
4281 if (name2 != NULL_TREE
4282 && TREE_CODE (name2) == SSA_NAME
4283 && TREE_CODE (cst2) == INTEGER_CST
4284 && INTEGRAL_TYPE_P (TREE_TYPE (name2))
4285 && live_on_edge (e, name2)
4286 && !has_single_use (name2))
4290 /* Build an expression for the range test. */
4292 if (TREE_TYPE (name) != TREE_TYPE (name2))
4293 tmp = build1 (NOP_EXPR, TREE_TYPE (name), tmp);
4294 if (cst2 != NULL_TREE)
4295 tmp = build2 (PLUS_EXPR, TREE_TYPE (name), tmp, cst2);
4299 fprintf (dump_file, "Adding assert for ");
4300 print_generic_expr (dump_file, name2, 0);
4301 fprintf (dump_file, " from ");
4302 print_generic_expr (dump_file, tmp, 0);
4303 fprintf (dump_file, "\n");
4306 register_new_assert_for (name2, tmp, comp_code, val, NULL, e, bsi);
4315 /* OP is an operand of a truth value expression which is known to have
4316 a particular value. Register any asserts for OP and for any
4317 operands in OP's defining statement.
4319 If CODE is EQ_EXPR, then we want to register OP is zero (false),
4320 if CODE is NE_EXPR, then we want to register OP is nonzero (true). */
4323 register_edge_assert_for_1 (tree op, enum tree_code code,
4324 edge e, gimple_stmt_iterator bsi)
4326 bool retval = false;
4329 enum tree_code rhs_code;
4331 /* We only care about SSA_NAMEs. */
4332 if (TREE_CODE (op) != SSA_NAME)
4335 /* We know that OP will have a zero or nonzero value. If OP is used
4336 more than once go ahead and register an assert for OP.
4338 The FOUND_IN_SUBGRAPH support is not helpful in this situation as
4339 it will always be set for OP (because OP is used in a COND_EXPR in
4341 if (!has_single_use (op))
4343 val = build_int_cst (TREE_TYPE (op), 0);
4344 register_new_assert_for (op, op, code, val, NULL, e, bsi);
4348 /* Now look at how OP is set. If it's set from a comparison,
4349 a truth operation or some bit operations, then we may be able
4350 to register information about the operands of that assignment. */
4351 op_def = SSA_NAME_DEF_STMT (op);
4352 if (gimple_code (op_def) != GIMPLE_ASSIGN)
4355 rhs_code = gimple_assign_rhs_code (op_def);
4357 if (TREE_CODE_CLASS (rhs_code) == tcc_comparison)
4359 bool invert = (code == EQ_EXPR ? true : false);
4360 tree op0 = gimple_assign_rhs1 (op_def);
4361 tree op1 = gimple_assign_rhs2 (op_def);
4363 if (TREE_CODE (op0) == SSA_NAME)
4364 retval |= register_edge_assert_for_2 (op0, e, bsi, rhs_code, op0, op1,
4366 if (TREE_CODE (op1) == SSA_NAME)
4367 retval |= register_edge_assert_for_2 (op1, e, bsi, rhs_code, op0, op1,
4370 else if ((code == NE_EXPR
4371 && (gimple_assign_rhs_code (op_def) == TRUTH_AND_EXPR
4372 || gimple_assign_rhs_code (op_def) == BIT_AND_EXPR))
4374 && (gimple_assign_rhs_code (op_def) == TRUTH_OR_EXPR
4375 || gimple_assign_rhs_code (op_def) == BIT_IOR_EXPR)))
4377 /* Recurse on each operand. */
4378 retval |= register_edge_assert_for_1 (gimple_assign_rhs1 (op_def),
4380 retval |= register_edge_assert_for_1 (gimple_assign_rhs2 (op_def),
4383 else if (gimple_assign_rhs_code (op_def) == TRUTH_NOT_EXPR)
4385 /* Recurse, flipping CODE. */
4386 code = invert_tree_comparison (code, false);
4387 retval |= register_edge_assert_for_1 (gimple_assign_rhs1 (op_def),
4390 else if (gimple_assign_rhs_code (op_def) == SSA_NAME)
4392 /* Recurse through the copy. */
4393 retval |= register_edge_assert_for_1 (gimple_assign_rhs1 (op_def),
4396 else if (CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (op_def)))
4398 /* Recurse through the type conversion. */
4399 retval |= register_edge_assert_for_1 (gimple_assign_rhs1 (op_def),
4406 /* Try to register an edge assertion for SSA name NAME on edge E for
4407 the condition COND contributing to the conditional jump pointed to by SI.
4408 Return true if an assertion for NAME could be registered. */
4411 register_edge_assert_for (tree name, edge e, gimple_stmt_iterator si,
4412 enum tree_code cond_code, tree cond_op0,
4416 enum tree_code comp_code;
4417 bool retval = false;
4418 bool is_else_edge = (e->flags & EDGE_FALSE_VALUE) != 0;
4420 /* Do not attempt to infer anything in names that flow through
4422 if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (name))
4425 if (!extract_code_and_val_from_cond_with_ops (name, cond_code,
4431 /* Register ASSERT_EXPRs for name. */
4432 retval |= register_edge_assert_for_2 (name, e, si, cond_code, cond_op0,
4433 cond_op1, is_else_edge);
4436 /* If COND is effectively an equality test of an SSA_NAME against
4437 the value zero or one, then we may be able to assert values
4438 for SSA_NAMEs which flow into COND. */
4440 /* In the case of NAME == 1 or NAME != 0, for TRUTH_AND_EXPR defining
4441 statement of NAME we can assert both operands of the TRUTH_AND_EXPR
4442 have nonzero value. */
4443 if (((comp_code == EQ_EXPR && integer_onep (val))
4444 || (comp_code == NE_EXPR && integer_zerop (val))))
4446 gimple def_stmt = SSA_NAME_DEF_STMT (name);
4448 if (is_gimple_assign (def_stmt)
4449 && (gimple_assign_rhs_code (def_stmt) == TRUTH_AND_EXPR
4450 || gimple_assign_rhs_code (def_stmt) == BIT_AND_EXPR))
4452 tree op0 = gimple_assign_rhs1 (def_stmt);
4453 tree op1 = gimple_assign_rhs2 (def_stmt);
4454 retval |= register_edge_assert_for_1 (op0, NE_EXPR, e, si);
4455 retval |= register_edge_assert_for_1 (op1, NE_EXPR, e, si);
4459 /* In the case of NAME == 0 or NAME != 1, for TRUTH_OR_EXPR defining
4460 statement of NAME we can assert both operands of the TRUTH_OR_EXPR
4462 if (((comp_code == EQ_EXPR && integer_zerop (val))
4463 || (comp_code == NE_EXPR && integer_onep (val))))
4465 gimple def_stmt = SSA_NAME_DEF_STMT (name);
4467 if (is_gimple_assign (def_stmt)
4468 && (gimple_assign_rhs_code (def_stmt) == TRUTH_OR_EXPR
4469 /* For BIT_IOR_EXPR only if NAME == 0 both operands have
4470 necessarily zero value. */
4471 || (comp_code == EQ_EXPR
4472 && (gimple_assign_rhs_code (def_stmt) == BIT_IOR_EXPR))))
4474 tree op0 = gimple_assign_rhs1 (def_stmt);
4475 tree op1 = gimple_assign_rhs2 (def_stmt);
4476 retval |= register_edge_assert_for_1 (op0, EQ_EXPR, e, si);
4477 retval |= register_edge_assert_for_1 (op1, EQ_EXPR, e, si);
4485 /* Determine whether the outgoing edges of BB should receive an
4486 ASSERT_EXPR for each of the operands of BB's LAST statement.
4487 The last statement of BB must be a COND_EXPR.
4489 If any of the sub-graphs rooted at BB have an interesting use of
4490 the predicate operands, an assert location node is added to the
4491 list of assertions for the corresponding operands. */
4494 find_conditional_asserts (basic_block bb, gimple last)
4497 gimple_stmt_iterator bsi;
4503 need_assert = false;
4504 bsi = gsi_for_stmt (last);
4506 /* Look for uses of the operands in each of the sub-graphs
4507 rooted at BB. We need to check each of the outgoing edges
4508 separately, so that we know what kind of ASSERT_EXPR to
4510 FOR_EACH_EDGE (e, ei, bb->succs)
4515 /* Register the necessary assertions for each operand in the
4516 conditional predicate. */
4517 FOR_EACH_SSA_TREE_OPERAND (op, last, iter, SSA_OP_USE)
4519 need_assert |= register_edge_assert_for (op, e, bsi,
4520 gimple_cond_code (last),
4521 gimple_cond_lhs (last),
4522 gimple_cond_rhs (last));
4529 /* Compare two case labels sorting first by the destination label uid
4530 and then by the case value. */
4533 compare_case_labels (const void *p1, const void *p2)
4535 const_tree const case1 = *(const_tree const*)p1;
4536 const_tree const case2 = *(const_tree const*)p2;
4537 unsigned int uid1 = DECL_UID (CASE_LABEL (case1));
4538 unsigned int uid2 = DECL_UID (CASE_LABEL (case2));
4542 else if (uid1 == uid2)
4544 /* Make sure the default label is first in a group. */
4545 if (!CASE_LOW (case1))
4547 else if (!CASE_LOW (case2))
4550 return tree_int_cst_compare (CASE_LOW (case1), CASE_LOW (case2));
4556 /* Determine whether the outgoing edges of BB should receive an
4557 ASSERT_EXPR for each of the operands of BB's LAST statement.
4558 The last statement of BB must be a SWITCH_EXPR.
4560 If any of the sub-graphs rooted at BB have an interesting use of
4561 the predicate operands, an assert location node is added to the
4562 list of assertions for the corresponding operands. */
4565 find_switch_asserts (basic_block bb, gimple last)
4568 gimple_stmt_iterator bsi;
4572 size_t n = gimple_switch_num_labels(last);
4573 #if GCC_VERSION >= 4000
4576 /* Work around GCC 3.4 bug (PR 37086). */
4577 volatile unsigned int idx;
4580 need_assert = false;
4581 bsi = gsi_for_stmt (last);
4582 op = gimple_switch_index (last);
4583 if (TREE_CODE (op) != SSA_NAME)
4586 /* Build a vector of case labels sorted by destination label. */
4587 vec2 = make_tree_vec (n);
4588 for (idx = 0; idx < n; ++idx)
4589 TREE_VEC_ELT (vec2, idx) = gimple_switch_label (last, idx);
4590 qsort (&TREE_VEC_ELT (vec2, 0), n, sizeof (tree), compare_case_labels);
4592 for (idx = 0; idx < n; ++idx)
4595 tree cl = TREE_VEC_ELT (vec2, idx);
4597 min = CASE_LOW (cl);
4598 max = CASE_HIGH (cl);
4600 /* If there are multiple case labels with the same destination
4601 we need to combine them to a single value range for the edge. */
4603 && CASE_LABEL (cl) == CASE_LABEL (TREE_VEC_ELT (vec2, idx + 1)))
4605 /* Skip labels until the last of the group. */
4609 && CASE_LABEL (cl) == CASE_LABEL (TREE_VEC_ELT (vec2, idx)));
4612 /* Pick up the maximum of the case label range. */
4613 if (CASE_HIGH (TREE_VEC_ELT (vec2, idx)))
4614 max = CASE_HIGH (TREE_VEC_ELT (vec2, idx));
4616 max = CASE_LOW (TREE_VEC_ELT (vec2, idx));
4619 /* Nothing to do if the range includes the default label until we
4620 can register anti-ranges. */
4621 if (min == NULL_TREE)
4624 /* Find the edge to register the assert expr on. */
4625 e = find_edge (bb, label_to_block (CASE_LABEL (cl)));
4627 /* Register the necessary assertions for the operand in the
4629 need_assert |= register_edge_assert_for (op, e, bsi,
4630 max ? GE_EXPR : EQ_EXPR,
4632 fold_convert (TREE_TYPE (op),
4636 need_assert |= register_edge_assert_for (op, e, bsi, LE_EXPR,
4638 fold_convert (TREE_TYPE (op),
4647 /* Traverse all the statements in block BB looking for statements that
4648 may generate useful assertions for the SSA names in their operand.
4649 If a statement produces a useful assertion A for name N_i, then the
4650 list of assertions already generated for N_i is scanned to
4651 determine if A is actually needed.
4653 If N_i already had the assertion A at a location dominating the
4654 current location, then nothing needs to be done. Otherwise, the
4655 new location for A is recorded instead.
4657 1- For every statement S in BB, all the variables used by S are
4658 added to bitmap FOUND_IN_SUBGRAPH.
4660 2- If statement S uses an operand N in a way that exposes a known
4661 value range for N, then if N was not already generated by an
4662 ASSERT_EXPR, create a new assert location for N. For instance,
4663 if N is a pointer and the statement dereferences it, we can
4664 assume that N is not NULL.
4666 3- COND_EXPRs are a special case of #2. We can derive range
4667 information from the predicate but need to insert different
4668 ASSERT_EXPRs for each of the sub-graphs rooted at the
4669 conditional block. If the last statement of BB is a conditional
4670 expression of the form 'X op Y', then
4672 a) Remove X and Y from the set FOUND_IN_SUBGRAPH.
4674 b) If the conditional is the only entry point to the sub-graph
4675 corresponding to the THEN_CLAUSE, recurse into it. On
4676 return, if X and/or Y are marked in FOUND_IN_SUBGRAPH, then
4677 an ASSERT_EXPR is added for the corresponding variable.
4679 c) Repeat step (b) on the ELSE_CLAUSE.
4681 d) Mark X and Y in FOUND_IN_SUBGRAPH.
4690 In this case, an assertion on the THEN clause is useful to
4691 determine that 'a' is always 9 on that edge. However, an assertion
4692 on the ELSE clause would be unnecessary.
4694 4- If BB does not end in a conditional expression, then we recurse
4695 into BB's dominator children.
4697 At the end of the recursive traversal, every SSA name will have a
4698 list of locations where ASSERT_EXPRs should be added. When a new
4699 location for name N is found, it is registered by calling
4700 register_new_assert_for. That function keeps track of all the
4701 registered assertions to prevent adding unnecessary assertions.
4702 For instance, if a pointer P_4 is dereferenced more than once in a
4703 dominator tree, only the location dominating all the dereference of
4704 P_4 will receive an ASSERT_EXPR.
4706 If this function returns true, then it means that there are names
4707 for which we need to generate ASSERT_EXPRs. Those assertions are
4708 inserted by process_assert_insertions. */
4711 find_assert_locations_1 (basic_block bb, sbitmap live)
4713 gimple_stmt_iterator si;
4718 need_assert = false;
4719 last = last_stmt (bb);
4721 /* If BB's last statement is a conditional statement involving integer
4722 operands, determine if we need to add ASSERT_EXPRs. */
4724 && gimple_code (last) == GIMPLE_COND
4725 && !fp_predicate (last)
4726 && !ZERO_SSA_OPERANDS (last, SSA_OP_USE))
4727 need_assert |= find_conditional_asserts (bb, last);
4729 /* If BB's last statement is a switch statement involving integer
4730 operands, determine if we need to add ASSERT_EXPRs. */
4732 && gimple_code (last) == GIMPLE_SWITCH
4733 && !ZERO_SSA_OPERANDS (last, SSA_OP_USE))
4734 need_assert |= find_switch_asserts (bb, last);
4736 /* Traverse all the statements in BB marking used names and looking
4737 for statements that may infer assertions for their used operands. */
4738 for (si = gsi_start_bb (bb); !gsi_end_p (si); gsi_next (&si))
4744 stmt = gsi_stmt (si);
4746 if (is_gimple_debug (stmt))
4749 /* See if we can derive an assertion for any of STMT's operands. */
4750 FOR_EACH_SSA_TREE_OPERAND (op, stmt, i, SSA_OP_USE)
4753 enum tree_code comp_code;
4755 /* Mark OP in our live bitmap. */
4756 SET_BIT (live, SSA_NAME_VERSION (op));
4758 /* If OP is used in such a way that we can infer a value
4759 range for it, and we don't find a previous assertion for
4760 it, create a new assertion location node for OP. */
4761 if (infer_value_range (stmt, op, &comp_code, &value))
4763 /* If we are able to infer a nonzero value range for OP,
4764 then walk backwards through the use-def chain to see if OP
4765 was set via a typecast.
4767 If so, then we can also infer a nonzero value range
4768 for the operand of the NOP_EXPR. */
4769 if (comp_code == NE_EXPR && integer_zerop (value))
4772 gimple def_stmt = SSA_NAME_DEF_STMT (t);
4774 while (is_gimple_assign (def_stmt)
4775 && gimple_assign_rhs_code (def_stmt) == NOP_EXPR
4777 (gimple_assign_rhs1 (def_stmt)) == SSA_NAME
4779 (TREE_TYPE (gimple_assign_rhs1 (def_stmt))))
4781 t = gimple_assign_rhs1 (def_stmt);
4782 def_stmt = SSA_NAME_DEF_STMT (t);
4784 /* Note we want to register the assert for the
4785 operand of the NOP_EXPR after SI, not after the
4787 if (! has_single_use (t))
4789 register_new_assert_for (t, t, comp_code, value,
4796 /* If OP is used only once, namely in this STMT, don't
4797 bother creating an ASSERT_EXPR for it. Such an
4798 ASSERT_EXPR would do nothing but increase compile time. */
4799 if (!has_single_use (op))
4801 register_new_assert_for (op, op, comp_code, value,
4809 /* Traverse all PHI nodes in BB marking used operands. */
4810 for (si = gsi_start_phis (bb); !gsi_end_p(si); gsi_next (&si))
4812 use_operand_p arg_p;
4814 phi = gsi_stmt (si);
4816 FOR_EACH_PHI_ARG (arg_p, phi, i, SSA_OP_USE)
4818 tree arg = USE_FROM_PTR (arg_p);
4819 if (TREE_CODE (arg) == SSA_NAME)
4820 SET_BIT (live, SSA_NAME_VERSION (arg));
4827 /* Do an RPO walk over the function computing SSA name liveness
4828 on-the-fly and deciding on assert expressions to insert.
4829 Returns true if there are assert expressions to be inserted. */
4832 find_assert_locations (void)
4834 int *rpo = XCNEWVEC (int, last_basic_block + NUM_FIXED_BLOCKS);
4835 int *bb_rpo = XCNEWVEC (int, last_basic_block + NUM_FIXED_BLOCKS);
4836 int *last_rpo = XCNEWVEC (int, last_basic_block + NUM_FIXED_BLOCKS);
4840 live = XCNEWVEC (sbitmap, last_basic_block + NUM_FIXED_BLOCKS);
4841 rpo_cnt = pre_and_rev_post_order_compute (NULL, rpo, false);
4842 for (i = 0; i < rpo_cnt; ++i)
4845 need_asserts = false;
4846 for (i = rpo_cnt-1; i >= 0; --i)
4848 basic_block bb = BASIC_BLOCK (rpo[i]);
4854 live[rpo[i]] = sbitmap_alloc (num_ssa_names);
4855 sbitmap_zero (live[rpo[i]]);
4858 /* Process BB and update the live information with uses in
4860 need_asserts |= find_assert_locations_1 (bb, live[rpo[i]]);
4862 /* Merge liveness into the predecessor blocks and free it. */
4863 if (!sbitmap_empty_p (live[rpo[i]]))
4866 FOR_EACH_EDGE (e, ei, bb->preds)
4868 int pred = e->src->index;
4869 if (e->flags & EDGE_DFS_BACK)
4874 live[pred] = sbitmap_alloc (num_ssa_names);
4875 sbitmap_zero (live[pred]);
4877 sbitmap_a_or_b (live[pred], live[pred], live[rpo[i]]);
4879 if (bb_rpo[pred] < pred_rpo)
4880 pred_rpo = bb_rpo[pred];
4883 /* Record the RPO number of the last visited block that needs
4884 live information from this block. */
4885 last_rpo[rpo[i]] = pred_rpo;
4889 sbitmap_free (live[rpo[i]]);
4890 live[rpo[i]] = NULL;
4893 /* We can free all successors live bitmaps if all their
4894 predecessors have been visited already. */
4895 FOR_EACH_EDGE (e, ei, bb->succs)
4896 if (last_rpo[e->dest->index] == i
4897 && live[e->dest->index])
4899 sbitmap_free (live[e->dest->index]);
4900 live[e->dest->index] = NULL;
4905 XDELETEVEC (bb_rpo);
4906 XDELETEVEC (last_rpo);
4907 for (i = 0; i < last_basic_block + NUM_FIXED_BLOCKS; ++i)
4909 sbitmap_free (live[i]);
4912 return need_asserts;
4915 /* Create an ASSERT_EXPR for NAME and insert it in the location
4916 indicated by LOC. Return true if we made any edge insertions. */
4919 process_assert_insertions_for (tree name, assert_locus_t loc)
4921 /* Build the comparison expression NAME_i COMP_CODE VAL. */
4928 /* If we have X <=> X do not insert an assert expr for that. */
4929 if (loc->expr == loc->val)
4932 cond = build2 (loc->comp_code, boolean_type_node, loc->expr, loc->val);
4933 assert_stmt = build_assert_expr_for (cond, name);
4936 /* We have been asked to insert the assertion on an edge. This
4937 is used only by COND_EXPR and SWITCH_EXPR assertions. */
4938 #if defined ENABLE_CHECKING
4939 gcc_assert (gimple_code (gsi_stmt (loc->si)) == GIMPLE_COND
4940 || gimple_code (gsi_stmt (loc->si)) == GIMPLE_SWITCH);
4943 gsi_insert_on_edge (loc->e, assert_stmt);
4947 /* Otherwise, we can insert right after LOC->SI iff the
4948 statement must not be the last statement in the block. */
4949 stmt = gsi_stmt (loc->si);
4950 if (!stmt_ends_bb_p (stmt))
4952 gsi_insert_after (&loc->si, assert_stmt, GSI_SAME_STMT);
4956 /* If STMT must be the last statement in BB, we can only insert new
4957 assertions on the non-abnormal edge out of BB. Note that since
4958 STMT is not control flow, there may only be one non-abnormal edge
4960 FOR_EACH_EDGE (e, ei, loc->bb->succs)
4961 if (!(e->flags & EDGE_ABNORMAL))
4963 gsi_insert_on_edge (e, assert_stmt);
4971 /* Process all the insertions registered for every name N_i registered
4972 in NEED_ASSERT_FOR. The list of assertions to be inserted are
4973 found in ASSERTS_FOR[i]. */
4976 process_assert_insertions (void)
4980 bool update_edges_p = false;
4981 int num_asserts = 0;
4983 if (dump_file && (dump_flags & TDF_DETAILS))
4984 dump_all_asserts (dump_file);
4986 EXECUTE_IF_SET_IN_BITMAP (need_assert_for, 0, i, bi)
4988 assert_locus_t loc = asserts_for[i];
4993 assert_locus_t next = loc->next;
4994 update_edges_p |= process_assert_insertions_for (ssa_name (i), loc);
5002 gsi_commit_edge_inserts ();
5004 statistics_counter_event (cfun, "Number of ASSERT_EXPR expressions inserted",
5009 /* Traverse the flowgraph looking for conditional jumps to insert range
5010 expressions. These range expressions are meant to provide information
5011 to optimizations that need to reason in terms of value ranges. They
5012 will not be expanded into RTL. For instance, given:
5021 this pass will transform the code into:
5027 x = ASSERT_EXPR <x, x < y>
5032 y = ASSERT_EXPR <y, x <= y>
5036 The idea is that once copy and constant propagation have run, other
5037 optimizations will be able to determine what ranges of values can 'x'
5038 take in different paths of the code, simply by checking the reaching
5039 definition of 'x'. */
5042 insert_range_assertions (void)
5044 need_assert_for = BITMAP_ALLOC (NULL);
5045 asserts_for = XCNEWVEC (assert_locus_t, num_ssa_names);
5047 calculate_dominance_info (CDI_DOMINATORS);
5049 if (find_assert_locations ())
5051 process_assert_insertions ();
5052 update_ssa (TODO_update_ssa_no_phi);
5055 if (dump_file && (dump_flags & TDF_DETAILS))
5057 fprintf (dump_file, "\nSSA form after inserting ASSERT_EXPRs\n");
5058 dump_function_to_file (current_function_decl, dump_file, dump_flags);
5062 BITMAP_FREE (need_assert_for);
5065 /* Checks one ARRAY_REF in REF, located at LOCUS. Ignores flexible arrays
5066 and "struct" hacks. If VRP can determine that the
5067 array subscript is a constant, check if it is outside valid
5068 range. If the array subscript is a RANGE, warn if it is
5069 non-overlapping with valid range.
5070 IGNORE_OFF_BY_ONE is true if the ARRAY_REF is inside a ADDR_EXPR. */
5073 check_array_ref (location_t location, tree ref, bool ignore_off_by_one)
5075 value_range_t* vr = NULL;
5076 tree low_sub, up_sub;
5077 tree low_bound, up_bound, up_bound_p1;
5080 if (TREE_NO_WARNING (ref))
5083 low_sub = up_sub = TREE_OPERAND (ref, 1);
5084 up_bound = array_ref_up_bound (ref);
5086 /* Can not check flexible arrays. */
5088 || TREE_CODE (up_bound) != INTEGER_CST)
5091 /* Accesses to trailing arrays via pointers may access storage
5092 beyond the types array bounds. */
5093 base = get_base_address (ref);
5094 if (base && TREE_CODE (base) == MEM_REF)
5096 tree cref, next = NULL_TREE;
5098 if (TREE_CODE (TREE_OPERAND (ref, 0)) != COMPONENT_REF)
5101 cref = TREE_OPERAND (ref, 0);
5102 if (TREE_CODE (TREE_TYPE (TREE_OPERAND (cref, 0))) == RECORD_TYPE)
5103 for (next = TREE_CHAIN (TREE_OPERAND (cref, 1));
5104 next && TREE_CODE (next) != FIELD_DECL;
5105 next = TREE_CHAIN (next))
5108 /* If this is the last field in a struct type or a field in a
5109 union type do not warn. */
5114 low_bound = array_ref_low_bound (ref);
5115 up_bound_p1 = int_const_binop (PLUS_EXPR, up_bound, integer_one_node, 0);
5117 if (TREE_CODE (low_sub) == SSA_NAME)
5119 vr = get_value_range (low_sub);
5120 if (vr->type == VR_RANGE || vr->type == VR_ANTI_RANGE)
5122 low_sub = vr->type == VR_RANGE ? vr->max : vr->min;
5123 up_sub = vr->type == VR_RANGE ? vr->min : vr->max;
5127 if (vr && vr->type == VR_ANTI_RANGE)
5129 if (TREE_CODE (up_sub) == INTEGER_CST
5130 && tree_int_cst_lt (up_bound, up_sub)
5131 && TREE_CODE (low_sub) == INTEGER_CST
5132 && tree_int_cst_lt (low_sub, low_bound))
5134 warning_at (location, OPT_Warray_bounds,
5135 "array subscript is outside array bounds");
5136 TREE_NO_WARNING (ref) = 1;
5139 else if (TREE_CODE (up_sub) == INTEGER_CST
5140 && (ignore_off_by_one
5141 ? (tree_int_cst_lt (up_bound, up_sub)
5142 && !tree_int_cst_equal (up_bound_p1, up_sub))
5143 : (tree_int_cst_lt (up_bound, up_sub)
5144 || tree_int_cst_equal (up_bound_p1, up_sub))))
5146 warning_at (location, OPT_Warray_bounds,
5147 "array subscript is above array bounds");
5148 TREE_NO_WARNING (ref) = 1;
5150 else if (TREE_CODE (low_sub) == INTEGER_CST
5151 && tree_int_cst_lt (low_sub, low_bound))
5153 warning_at (location, OPT_Warray_bounds,
5154 "array subscript is below array bounds");
5155 TREE_NO_WARNING (ref) = 1;
5159 /* Searches if the expr T, located at LOCATION computes
5160 address of an ARRAY_REF, and call check_array_ref on it. */
5163 search_for_addr_array (tree t, location_t location)
5165 while (TREE_CODE (t) == SSA_NAME)
5167 gimple g = SSA_NAME_DEF_STMT (t);
5169 if (gimple_code (g) != GIMPLE_ASSIGN)
5172 if (get_gimple_rhs_class (gimple_assign_rhs_code (g))
5173 != GIMPLE_SINGLE_RHS)
5176 t = gimple_assign_rhs1 (g);
5180 /* We are only interested in addresses of ARRAY_REF's. */
5181 if (TREE_CODE (t) != ADDR_EXPR)
5184 /* Check each ARRAY_REFs in the reference chain. */
5187 if (TREE_CODE (t) == ARRAY_REF)
5188 check_array_ref (location, t, true /*ignore_off_by_one*/);
5190 t = TREE_OPERAND (t, 0);
5192 while (handled_component_p (t));
5194 if (TREE_CODE (t) == MEM_REF
5195 && TREE_CODE (TREE_OPERAND (t, 0)) == ADDR_EXPR
5196 && !TREE_NO_WARNING (t))
5198 tree tem = TREE_OPERAND (TREE_OPERAND (t, 0), 0);
5199 tree low_bound, up_bound, el_sz;
5201 if (TREE_CODE (TREE_TYPE (tem)) != ARRAY_TYPE
5202 || TREE_CODE (TREE_TYPE (TREE_TYPE (tem))) == ARRAY_TYPE
5203 || !TYPE_DOMAIN (TREE_TYPE (tem)))
5206 low_bound = TYPE_MIN_VALUE (TYPE_DOMAIN (TREE_TYPE (tem)));
5207 up_bound = TYPE_MAX_VALUE (TYPE_DOMAIN (TREE_TYPE (tem)));
5208 el_sz = TYPE_SIZE_UNIT (TREE_TYPE (TREE_TYPE (tem)));
5210 || TREE_CODE (low_bound) != INTEGER_CST
5212 || TREE_CODE (up_bound) != INTEGER_CST
5214 || TREE_CODE (el_sz) != INTEGER_CST)
5217 idx = mem_ref_offset (t);
5218 idx = double_int_sdiv (idx, tree_to_double_int (el_sz), TRUNC_DIV_EXPR);
5219 if (double_int_scmp (idx, double_int_zero) < 0)
5221 warning_at (location, OPT_Warray_bounds,
5222 "array subscript is below array bounds");
5223 TREE_NO_WARNING (t) = 1;
5225 else if (double_int_scmp (idx,
5228 (tree_to_double_int (up_bound),
5230 (tree_to_double_int (low_bound))),
5231 double_int_one)) > 0)
5233 warning_at (location, OPT_Warray_bounds,
5234 "array subscript is above array bounds");
5235 TREE_NO_WARNING (t) = 1;
5240 /* walk_tree() callback that checks if *TP is
5241 an ARRAY_REF inside an ADDR_EXPR (in which an array
5242 subscript one outside the valid range is allowed). Call
5243 check_array_ref for each ARRAY_REF found. The location is
5247 check_array_bounds (tree *tp, int *walk_subtree, void *data)
5250 struct walk_stmt_info *wi = (struct walk_stmt_info *) data;
5251 location_t location;
5253 if (EXPR_HAS_LOCATION (t))
5254 location = EXPR_LOCATION (t);
5257 location_t *locp = (location_t *) wi->info;
5261 *walk_subtree = TRUE;
5263 if (TREE_CODE (t) == ARRAY_REF)
5264 check_array_ref (location, t, false /*ignore_off_by_one*/);
5266 if (TREE_CODE (t) == MEM_REF
5267 || (TREE_CODE (t) == RETURN_EXPR && TREE_OPERAND (t, 0)))
5268 search_for_addr_array (TREE_OPERAND (t, 0), location);
5270 if (TREE_CODE (t) == ADDR_EXPR)
5271 *walk_subtree = FALSE;
5276 /* Walk over all statements of all reachable BBs and call check_array_bounds
5280 check_all_array_refs (void)
5283 gimple_stmt_iterator si;
5289 bool executable = false;
5291 /* Skip blocks that were found to be unreachable. */
5292 FOR_EACH_EDGE (e, ei, bb->preds)
5293 executable |= !!(e->flags & EDGE_EXECUTABLE);
5297 for (si = gsi_start_bb (bb); !gsi_end_p (si); gsi_next (&si))
5299 gimple stmt = gsi_stmt (si);
5300 struct walk_stmt_info wi;
5301 if (!gimple_has_location (stmt))
5304 if (is_gimple_call (stmt))
5307 size_t n = gimple_call_num_args (stmt);
5308 for (i = 0; i < n; i++)
5310 tree arg = gimple_call_arg (stmt, i);
5311 search_for_addr_array (arg, gimple_location (stmt));
5316 memset (&wi, 0, sizeof (wi));
5317 wi.info = CONST_CAST (void *, (const void *)
5318 gimple_location_ptr (stmt));
5320 walk_gimple_op (gsi_stmt (si),
5328 /* Convert range assertion expressions into the implied copies and
5329 copy propagate away the copies. Doing the trivial copy propagation
5330 here avoids the need to run the full copy propagation pass after
5333 FIXME, this will eventually lead to copy propagation removing the
5334 names that had useful range information attached to them. For
5335 instance, if we had the assertion N_i = ASSERT_EXPR <N_j, N_j > 3>,
5336 then N_i will have the range [3, +INF].
5338 However, by converting the assertion into the implied copy
5339 operation N_i = N_j, we will then copy-propagate N_j into the uses
5340 of N_i and lose the range information. We may want to hold on to
5341 ASSERT_EXPRs a little while longer as the ranges could be used in
5342 things like jump threading.
5344 The problem with keeping ASSERT_EXPRs around is that passes after
5345 VRP need to handle them appropriately.
5347 Another approach would be to make the range information a first
5348 class property of the SSA_NAME so that it can be queried from
5349 any pass. This is made somewhat more complex by the need for
5350 multiple ranges to be associated with one SSA_NAME. */
5353 remove_range_assertions (void)
5356 gimple_stmt_iterator si;
5358 /* Note that the BSI iterator bump happens at the bottom of the
5359 loop and no bump is necessary if we're removing the statement
5360 referenced by the current BSI. */
5362 for (si = gsi_start_bb (bb); !gsi_end_p (si);)
5364 gimple stmt = gsi_stmt (si);
5367 if (is_gimple_assign (stmt)
5368 && gimple_assign_rhs_code (stmt) == ASSERT_EXPR)
5370 tree rhs = gimple_assign_rhs1 (stmt);
5372 tree cond = fold (ASSERT_EXPR_COND (rhs));
5373 use_operand_p use_p;
5374 imm_use_iterator iter;
5376 gcc_assert (cond != boolean_false_node);
5378 /* Propagate the RHS into every use of the LHS. */
5379 var = ASSERT_EXPR_VAR (rhs);
5380 FOR_EACH_IMM_USE_STMT (use_stmt, iter,
5381 gimple_assign_lhs (stmt))
5382 FOR_EACH_IMM_USE_ON_STMT (use_p, iter)
5384 SET_USE (use_p, var);
5385 gcc_assert (TREE_CODE (var) == SSA_NAME);
5388 /* And finally, remove the copy, it is not needed. */
5389 gsi_remove (&si, true);
5390 release_defs (stmt);
5398 /* Return true if STMT is interesting for VRP. */
5401 stmt_interesting_for_vrp (gimple stmt)
5403 if (gimple_code (stmt) == GIMPLE_PHI
5404 && is_gimple_reg (gimple_phi_result (stmt))
5405 && (INTEGRAL_TYPE_P (TREE_TYPE (gimple_phi_result (stmt)))
5406 || POINTER_TYPE_P (TREE_TYPE (gimple_phi_result (stmt)))))
5408 else if (is_gimple_assign (stmt) || is_gimple_call (stmt))
5410 tree lhs = gimple_get_lhs (stmt);
5412 /* In general, assignments with virtual operands are not useful
5413 for deriving ranges, with the obvious exception of calls to
5414 builtin functions. */
5415 if (lhs && TREE_CODE (lhs) == SSA_NAME
5416 && (INTEGRAL_TYPE_P (TREE_TYPE (lhs))
5417 || POINTER_TYPE_P (TREE_TYPE (lhs)))
5418 && ((is_gimple_call (stmt)
5419 && gimple_call_fndecl (stmt) != NULL_TREE
5420 && DECL_IS_BUILTIN (gimple_call_fndecl (stmt)))
5421 || !gimple_vuse (stmt)))
5424 else if (gimple_code (stmt) == GIMPLE_COND
5425 || gimple_code (stmt) == GIMPLE_SWITCH)
5432 /* Initialize local data structures for VRP. */
5435 vrp_initialize (void)
5439 vr_value = XCNEWVEC (value_range_t *, num_ssa_names);
5440 vr_phi_edge_counts = XCNEWVEC (int, num_ssa_names);
5444 gimple_stmt_iterator si;
5446 for (si = gsi_start_phis (bb); !gsi_end_p (si); gsi_next (&si))
5448 gimple phi = gsi_stmt (si);
5449 if (!stmt_interesting_for_vrp (phi))
5451 tree lhs = PHI_RESULT (phi);
5452 set_value_range_to_varying (get_value_range (lhs));
5453 prop_set_simulate_again (phi, false);
5456 prop_set_simulate_again (phi, true);
5459 for (si = gsi_start_bb (bb); !gsi_end_p (si); gsi_next (&si))
5461 gimple stmt = gsi_stmt (si);
5463 /* If the statement is a control insn, then we do not
5464 want to avoid simulating the statement once. Failure
5465 to do so means that those edges will never get added. */
5466 if (stmt_ends_bb_p (stmt))
5467 prop_set_simulate_again (stmt, true);
5468 else if (!stmt_interesting_for_vrp (stmt))
5472 FOR_EACH_SSA_TREE_OPERAND (def, stmt, i, SSA_OP_DEF)
5473 set_value_range_to_varying (get_value_range (def));
5474 prop_set_simulate_again (stmt, false);
5477 prop_set_simulate_again (stmt, true);
5483 /* Visit assignment STMT. If it produces an interesting range, record
5484 the SSA name in *OUTPUT_P. */
5486 static enum ssa_prop_result
5487 vrp_visit_assignment_or_call (gimple stmt, tree *output_p)
5491 enum gimple_code code = gimple_code (stmt);
5492 lhs = gimple_get_lhs (stmt);
5494 /* We only keep track of ranges in integral and pointer types. */
5495 if (TREE_CODE (lhs) == SSA_NAME
5496 && ((INTEGRAL_TYPE_P (TREE_TYPE (lhs))
5497 /* It is valid to have NULL MIN/MAX values on a type. See
5498 build_range_type. */
5499 && TYPE_MIN_VALUE (TREE_TYPE (lhs))
5500 && TYPE_MAX_VALUE (TREE_TYPE (lhs)))
5501 || POINTER_TYPE_P (TREE_TYPE (lhs))))
5503 value_range_t new_vr = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
5505 if (code == GIMPLE_CALL)
5506 extract_range_basic (&new_vr, stmt);
5508 extract_range_from_assignment (&new_vr, stmt);
5510 if (update_value_range (lhs, &new_vr))
5514 if (dump_file && (dump_flags & TDF_DETAILS))
5516 fprintf (dump_file, "Found new range for ");
5517 print_generic_expr (dump_file, lhs, 0);
5518 fprintf (dump_file, ": ");
5519 dump_value_range (dump_file, &new_vr);
5520 fprintf (dump_file, "\n\n");
5523 if (new_vr.type == VR_VARYING)
5524 return SSA_PROP_VARYING;
5526 return SSA_PROP_INTERESTING;
5529 return SSA_PROP_NOT_INTERESTING;
5532 /* Every other statement produces no useful ranges. */
5533 FOR_EACH_SSA_TREE_OPERAND (def, stmt, iter, SSA_OP_DEF)
5534 set_value_range_to_varying (get_value_range (def));
5536 return SSA_PROP_VARYING;
5539 /* Helper that gets the value range of the SSA_NAME with version I
5540 or a symbolic range containing the SSA_NAME only if the value range
5541 is varying or undefined. */
5543 static inline value_range_t
5544 get_vr_for_comparison (int i)
5546 value_range_t vr = *(vr_value[i]);
5548 /* If name N_i does not have a valid range, use N_i as its own
5549 range. This allows us to compare against names that may
5550 have N_i in their ranges. */
5551 if (vr.type == VR_VARYING || vr.type == VR_UNDEFINED)
5554 vr.min = ssa_name (i);
5555 vr.max = ssa_name (i);
5561 /* Compare all the value ranges for names equivalent to VAR with VAL
5562 using comparison code COMP. Return the same value returned by
5563 compare_range_with_value, including the setting of
5564 *STRICT_OVERFLOW_P. */
5567 compare_name_with_value (enum tree_code comp, tree var, tree val,
5568 bool *strict_overflow_p)
5574 int used_strict_overflow;
5576 value_range_t equiv_vr;
5578 /* Get the set of equivalences for VAR. */
5579 e = get_value_range (var)->equiv;
5581 /* Start at -1. Set it to 0 if we do a comparison without relying
5582 on overflow, or 1 if all comparisons rely on overflow. */
5583 used_strict_overflow = -1;
5585 /* Compare vars' value range with val. */
5586 equiv_vr = get_vr_for_comparison (SSA_NAME_VERSION (var));
5588 retval = compare_range_with_value (comp, &equiv_vr, val, &sop);
5590 used_strict_overflow = sop ? 1 : 0;
5592 /* If the equiv set is empty we have done all work we need to do. */
5596 && used_strict_overflow > 0)
5597 *strict_overflow_p = true;
5601 EXECUTE_IF_SET_IN_BITMAP (e, 0, i, bi)
5603 equiv_vr = get_vr_for_comparison (i);
5605 t = compare_range_with_value (comp, &equiv_vr, val, &sop);
5608 /* If we get different answers from different members
5609 of the equivalence set this check must be in a dead
5610 code region. Folding it to a trap representation
5611 would be correct here. For now just return don't-know. */
5621 used_strict_overflow = 0;
5622 else if (used_strict_overflow < 0)
5623 used_strict_overflow = 1;
5628 && used_strict_overflow > 0)
5629 *strict_overflow_p = true;
5635 /* Given a comparison code COMP and names N1 and N2, compare all the
5636 ranges equivalent to N1 against all the ranges equivalent to N2
5637 to determine the value of N1 COMP N2. Return the same value
5638 returned by compare_ranges. Set *STRICT_OVERFLOW_P to indicate
5639 whether we relied on an overflow infinity in the comparison. */
5643 compare_names (enum tree_code comp, tree n1, tree n2,
5644 bool *strict_overflow_p)
5648 bitmap_iterator bi1, bi2;
5650 int used_strict_overflow;
5651 static bitmap_obstack *s_obstack = NULL;
5652 static bitmap s_e1 = NULL, s_e2 = NULL;
5654 /* Compare the ranges of every name equivalent to N1 against the
5655 ranges of every name equivalent to N2. */
5656 e1 = get_value_range (n1)->equiv;
5657 e2 = get_value_range (n2)->equiv;
5659 /* Use the fake bitmaps if e1 or e2 are not available. */
5660 if (s_obstack == NULL)
5662 s_obstack = XNEW (bitmap_obstack);
5663 bitmap_obstack_initialize (s_obstack);
5664 s_e1 = BITMAP_ALLOC (s_obstack);
5665 s_e2 = BITMAP_ALLOC (s_obstack);
5672 /* Add N1 and N2 to their own set of equivalences to avoid
5673 duplicating the body of the loop just to check N1 and N2
5675 bitmap_set_bit (e1, SSA_NAME_VERSION (n1));
5676 bitmap_set_bit (e2, SSA_NAME_VERSION (n2));
5678 /* If the equivalence sets have a common intersection, then the two
5679 names can be compared without checking their ranges. */
5680 if (bitmap_intersect_p (e1, e2))
5682 bitmap_clear_bit (e1, SSA_NAME_VERSION (n1));
5683 bitmap_clear_bit (e2, SSA_NAME_VERSION (n2));
5685 return (comp == EQ_EXPR || comp == GE_EXPR || comp == LE_EXPR)
5687 : boolean_false_node;
5690 /* Start at -1. Set it to 0 if we do a comparison without relying
5691 on overflow, or 1 if all comparisons rely on overflow. */
5692 used_strict_overflow = -1;
5694 /* Otherwise, compare all the equivalent ranges. First, add N1 and
5695 N2 to their own set of equivalences to avoid duplicating the body
5696 of the loop just to check N1 and N2 ranges. */
5697 EXECUTE_IF_SET_IN_BITMAP (e1, 0, i1, bi1)
5699 value_range_t vr1 = get_vr_for_comparison (i1);
5701 t = retval = NULL_TREE;
5702 EXECUTE_IF_SET_IN_BITMAP (e2, 0, i2, bi2)
5706 value_range_t vr2 = get_vr_for_comparison (i2);
5708 t = compare_ranges (comp, &vr1, &vr2, &sop);
5711 /* If we get different answers from different members
5712 of the equivalence set this check must be in a dead
5713 code region. Folding it to a trap representation
5714 would be correct here. For now just return don't-know. */
5718 bitmap_clear_bit (e1, SSA_NAME_VERSION (n1));
5719 bitmap_clear_bit (e2, SSA_NAME_VERSION (n2));
5725 used_strict_overflow = 0;
5726 else if (used_strict_overflow < 0)
5727 used_strict_overflow = 1;
5733 bitmap_clear_bit (e1, SSA_NAME_VERSION (n1));
5734 bitmap_clear_bit (e2, SSA_NAME_VERSION (n2));
5735 if (used_strict_overflow > 0)
5736 *strict_overflow_p = true;
5741 /* None of the equivalent ranges are useful in computing this
5743 bitmap_clear_bit (e1, SSA_NAME_VERSION (n1));
5744 bitmap_clear_bit (e2, SSA_NAME_VERSION (n2));
5748 /* Helper function for vrp_evaluate_conditional_warnv. */
5751 vrp_evaluate_conditional_warnv_with_ops_using_ranges (enum tree_code code,
5753 bool * strict_overflow_p)
5755 value_range_t *vr0, *vr1;
5757 vr0 = (TREE_CODE (op0) == SSA_NAME) ? get_value_range (op0) : NULL;
5758 vr1 = (TREE_CODE (op1) == SSA_NAME) ? get_value_range (op1) : NULL;
5761 return compare_ranges (code, vr0, vr1, strict_overflow_p);
5762 else if (vr0 && vr1 == NULL)
5763 return compare_range_with_value (code, vr0, op1, strict_overflow_p);
5764 else if (vr0 == NULL && vr1)
5765 return (compare_range_with_value
5766 (swap_tree_comparison (code), vr1, op0, strict_overflow_p));
5770 /* Helper function for vrp_evaluate_conditional_warnv. */
5773 vrp_evaluate_conditional_warnv_with_ops (enum tree_code code, tree op0,
5774 tree op1, bool use_equiv_p,
5775 bool *strict_overflow_p, bool *only_ranges)
5779 *only_ranges = true;
5781 /* We only deal with integral and pointer types. */
5782 if (!INTEGRAL_TYPE_P (TREE_TYPE (op0))
5783 && !POINTER_TYPE_P (TREE_TYPE (op0)))
5789 && (ret = vrp_evaluate_conditional_warnv_with_ops_using_ranges
5790 (code, op0, op1, strict_overflow_p)))
5792 *only_ranges = false;
5793 if (TREE_CODE (op0) == SSA_NAME && TREE_CODE (op1) == SSA_NAME)
5794 return compare_names (code, op0, op1, strict_overflow_p);
5795 else if (TREE_CODE (op0) == SSA_NAME)
5796 return compare_name_with_value (code, op0, op1, strict_overflow_p);
5797 else if (TREE_CODE (op1) == SSA_NAME)
5798 return (compare_name_with_value
5799 (swap_tree_comparison (code), op1, op0, strict_overflow_p));
5802 return vrp_evaluate_conditional_warnv_with_ops_using_ranges (code, op0, op1,
5807 /* Given (CODE OP0 OP1) within STMT, try to simplify it based on value range
5808 information. Return NULL if the conditional can not be evaluated.
5809 The ranges of all the names equivalent with the operands in COND
5810 will be used when trying to compute the value. If the result is
5811 based on undefined signed overflow, issue a warning if
5815 vrp_evaluate_conditional (enum tree_code code, tree op0, tree op1, gimple stmt)
5821 /* Some passes and foldings leak constants with overflow flag set
5822 into the IL. Avoid doing wrong things with these and bail out. */
5823 if ((TREE_CODE (op0) == INTEGER_CST
5824 && TREE_OVERFLOW (op0))
5825 || (TREE_CODE (op1) == INTEGER_CST
5826 && TREE_OVERFLOW (op1)))
5830 ret = vrp_evaluate_conditional_warnv_with_ops (code, op0, op1, true, &sop,
5835 enum warn_strict_overflow_code wc;
5836 const char* warnmsg;
5838 if (is_gimple_min_invariant (ret))
5840 wc = WARN_STRICT_OVERFLOW_CONDITIONAL;
5841 warnmsg = G_("assuming signed overflow does not occur when "
5842 "simplifying conditional to constant");
5846 wc = WARN_STRICT_OVERFLOW_COMPARISON;
5847 warnmsg = G_("assuming signed overflow does not occur when "
5848 "simplifying conditional");
5851 if (issue_strict_overflow_warning (wc))
5853 location_t location;
5855 if (!gimple_has_location (stmt))
5856 location = input_location;
5858 location = gimple_location (stmt);
5859 warning_at (location, OPT_Wstrict_overflow, "%s", warnmsg);
5863 if (warn_type_limits
5864 && ret && only_ranges
5865 && TREE_CODE_CLASS (code) == tcc_comparison
5866 && TREE_CODE (op0) == SSA_NAME)
5868 /* If the comparison is being folded and the operand on the LHS
5869 is being compared against a constant value that is outside of
5870 the natural range of OP0's type, then the predicate will
5871 always fold regardless of the value of OP0. If -Wtype-limits
5872 was specified, emit a warning. */
5873 tree type = TREE_TYPE (op0);
5874 value_range_t *vr0 = get_value_range (op0);
5876 if (vr0->type != VR_VARYING
5877 && INTEGRAL_TYPE_P (type)
5878 && vrp_val_is_min (vr0->min)
5879 && vrp_val_is_max (vr0->max)
5880 && is_gimple_min_invariant (op1))
5882 location_t location;
5884 if (!gimple_has_location (stmt))
5885 location = input_location;
5887 location = gimple_location (stmt);
5889 warning_at (location, OPT_Wtype_limits,
5891 ? G_("comparison always false "
5892 "due to limited range of data type")
5893 : G_("comparison always true "
5894 "due to limited range of data type"));
5902 /* Visit conditional statement STMT. If we can determine which edge
5903 will be taken out of STMT's basic block, record it in
5904 *TAKEN_EDGE_P and return SSA_PROP_INTERESTING. Otherwise, return
5905 SSA_PROP_VARYING. */
5907 static enum ssa_prop_result
5908 vrp_visit_cond_stmt (gimple stmt, edge *taken_edge_p)
5913 *taken_edge_p = NULL;
5915 if (dump_file && (dump_flags & TDF_DETAILS))
5920 fprintf (dump_file, "\nVisiting conditional with predicate: ");
5921 print_gimple_stmt (dump_file, stmt, 0, 0);
5922 fprintf (dump_file, "\nWith known ranges\n");
5924 FOR_EACH_SSA_TREE_OPERAND (use, stmt, i, SSA_OP_USE)
5926 fprintf (dump_file, "\t");
5927 print_generic_expr (dump_file, use, 0);
5928 fprintf (dump_file, ": ");
5929 dump_value_range (dump_file, vr_value[SSA_NAME_VERSION (use)]);
5932 fprintf (dump_file, "\n");
5935 /* Compute the value of the predicate COND by checking the known
5936 ranges of each of its operands.
5938 Note that we cannot evaluate all the equivalent ranges here
5939 because those ranges may not yet be final and with the current
5940 propagation strategy, we cannot determine when the value ranges
5941 of the names in the equivalence set have changed.
5943 For instance, given the following code fragment
5947 i_14 = ASSERT_EXPR <i_5, i_5 != 0>
5951 Assume that on the first visit to i_14, i_5 has the temporary
5952 range [8, 8] because the second argument to the PHI function is
5953 not yet executable. We derive the range ~[0, 0] for i_14 and the
5954 equivalence set { i_5 }. So, when we visit 'if (i_14 == 1)' for
5955 the first time, since i_14 is equivalent to the range [8, 8], we
5956 determine that the predicate is always false.
5958 On the next round of propagation, i_13 is determined to be
5959 VARYING, which causes i_5 to drop down to VARYING. So, another
5960 visit to i_14 is scheduled. In this second visit, we compute the
5961 exact same range and equivalence set for i_14, namely ~[0, 0] and
5962 { i_5 }. But we did not have the previous range for i_5
5963 registered, so vrp_visit_assignment thinks that the range for
5964 i_14 has not changed. Therefore, the predicate 'if (i_14 == 1)'
5965 is not visited again, which stops propagation from visiting
5966 statements in the THEN clause of that if().
5968 To properly fix this we would need to keep the previous range
5969 value for the names in the equivalence set. This way we would've
5970 discovered that from one visit to the other i_5 changed from
5971 range [8, 8] to VR_VARYING.
5973 However, fixing this apparent limitation may not be worth the
5974 additional checking. Testing on several code bases (GCC, DLV,
5975 MICO, TRAMP3D and SPEC2000) showed that doing this results in
5976 4 more predicates folded in SPEC. */
5979 val = vrp_evaluate_conditional_warnv_with_ops (gimple_cond_code (stmt),
5980 gimple_cond_lhs (stmt),
5981 gimple_cond_rhs (stmt),
5986 *taken_edge_p = find_taken_edge (gimple_bb (stmt), val);
5989 if (dump_file && (dump_flags & TDF_DETAILS))
5991 "\nIgnoring predicate evaluation because "
5992 "it assumes that signed overflow is undefined");
5997 if (dump_file && (dump_flags & TDF_DETAILS))
5999 fprintf (dump_file, "\nPredicate evaluates to: ");
6000 if (val == NULL_TREE)
6001 fprintf (dump_file, "DON'T KNOW\n");
6003 print_generic_stmt (dump_file, val, 0);
6006 return (*taken_edge_p) ? SSA_PROP_INTERESTING : SSA_PROP_VARYING;
6009 /* Searches the case label vector VEC for the index *IDX of the CASE_LABEL
6010 that includes the value VAL. The search is restricted to the range
6011 [START_IDX, n - 1] where n is the size of VEC.
6013 If there is a CASE_LABEL for VAL, its index is placed in IDX and true is
6016 If there is no CASE_LABEL for VAL and there is one that is larger than VAL,
6017 it is placed in IDX and false is returned.
6019 If VAL is larger than any CASE_LABEL, n is placed on IDX and false is
6023 find_case_label_index (gimple stmt, size_t start_idx, tree val, size_t *idx)
6025 size_t n = gimple_switch_num_labels (stmt);
6028 /* Find case label for minimum of the value range or the next one.
6029 At each iteration we are searching in [low, high - 1]. */
6031 for (low = start_idx, high = n; high != low; )
6035 /* Note that i != high, so we never ask for n. */
6036 size_t i = (high + low) / 2;
6037 t = gimple_switch_label (stmt, i);
6039 /* Cache the result of comparing CASE_LOW and val. */
6040 cmp = tree_int_cst_compare (CASE_LOW (t), val);
6044 /* Ranges cannot be empty. */
6053 if (CASE_HIGH (t) != NULL
6054 && tree_int_cst_compare (CASE_HIGH (t), val) >= 0)
6066 /* Searches the case label vector VEC for the range of CASE_LABELs that is used
6067 for values between MIN and MAX. The first index is placed in MIN_IDX. The
6068 last index is placed in MAX_IDX. If the range of CASE_LABELs is empty
6069 then MAX_IDX < MIN_IDX.
6070 Returns true if the default label is not needed. */
6073 find_case_label_range (gimple stmt, tree min, tree max, size_t *min_idx,
6077 bool min_take_default = !find_case_label_index (stmt, 1, min, &i);
6078 bool max_take_default = !find_case_label_index (stmt, i, max, &j);
6082 && max_take_default)
6084 /* Only the default case label reached.
6085 Return an empty range. */
6092 bool take_default = min_take_default || max_take_default;
6096 if (max_take_default)
6099 /* If the case label range is continuous, we do not need
6100 the default case label. Verify that. */
6101 high = CASE_LOW (gimple_switch_label (stmt, i));
6102 if (CASE_HIGH (gimple_switch_label (stmt, i)))
6103 high = CASE_HIGH (gimple_switch_label (stmt, i));
6104 for (k = i + 1; k <= j; ++k)
6106 low = CASE_LOW (gimple_switch_label (stmt, k));
6107 if (!integer_onep (int_const_binop (MINUS_EXPR, low, high, 0)))
6109 take_default = true;
6113 if (CASE_HIGH (gimple_switch_label (stmt, k)))
6114 high = CASE_HIGH (gimple_switch_label (stmt, k));
6119 return !take_default;
6123 /* Visit switch statement STMT. If we can determine which edge
6124 will be taken out of STMT's basic block, record it in
6125 *TAKEN_EDGE_P and return SSA_PROP_INTERESTING. Otherwise, return
6126 SSA_PROP_VARYING. */
6128 static enum ssa_prop_result
6129 vrp_visit_switch_stmt (gimple stmt, edge *taken_edge_p)
6133 size_t i = 0, j = 0;
6136 *taken_edge_p = NULL;
6137 op = gimple_switch_index (stmt);
6138 if (TREE_CODE (op) != SSA_NAME)
6139 return SSA_PROP_VARYING;
6141 vr = get_value_range (op);
6142 if (dump_file && (dump_flags & TDF_DETAILS))
6144 fprintf (dump_file, "\nVisiting switch expression with operand ");
6145 print_generic_expr (dump_file, op, 0);
6146 fprintf (dump_file, " with known range ");
6147 dump_value_range (dump_file, vr);
6148 fprintf (dump_file, "\n");
6151 if (vr->type != VR_RANGE
6152 || symbolic_range_p (vr))
6153 return SSA_PROP_VARYING;
6155 /* Find the single edge that is taken from the switch expression. */
6156 take_default = !find_case_label_range (stmt, vr->min, vr->max, &i, &j);
6158 /* Check if the range spans no CASE_LABEL. If so, we only reach the default
6162 gcc_assert (take_default);
6163 val = gimple_switch_default_label (stmt);
6167 /* Check if labels with index i to j and maybe the default label
6168 are all reaching the same label. */
6170 val = gimple_switch_label (stmt, i);
6172 && CASE_LABEL (gimple_switch_default_label (stmt))
6173 != CASE_LABEL (val))
6175 if (dump_file && (dump_flags & TDF_DETAILS))
6176 fprintf (dump_file, " not a single destination for this "
6178 return SSA_PROP_VARYING;
6180 for (++i; i <= j; ++i)
6182 if (CASE_LABEL (gimple_switch_label (stmt, i)) != CASE_LABEL (val))
6184 if (dump_file && (dump_flags & TDF_DETAILS))
6185 fprintf (dump_file, " not a single destination for this "
6187 return SSA_PROP_VARYING;
6192 *taken_edge_p = find_edge (gimple_bb (stmt),
6193 label_to_block (CASE_LABEL (val)));
6195 if (dump_file && (dump_flags & TDF_DETAILS))
6197 fprintf (dump_file, " will take edge to ");
6198 print_generic_stmt (dump_file, CASE_LABEL (val), 0);
6201 return SSA_PROP_INTERESTING;
6205 /* Evaluate statement STMT. If the statement produces a useful range,
6206 return SSA_PROP_INTERESTING and record the SSA name with the
6207 interesting range into *OUTPUT_P.
6209 If STMT is a conditional branch and we can determine its truth
6210 value, the taken edge is recorded in *TAKEN_EDGE_P.
6212 If STMT produces a varying value, return SSA_PROP_VARYING. */
6214 static enum ssa_prop_result
6215 vrp_visit_stmt (gimple stmt, edge *taken_edge_p, tree *output_p)
6220 if (dump_file && (dump_flags & TDF_DETAILS))
6222 fprintf (dump_file, "\nVisiting statement:\n");
6223 print_gimple_stmt (dump_file, stmt, 0, dump_flags);
6224 fprintf (dump_file, "\n");
6227 if (!stmt_interesting_for_vrp (stmt))
6228 gcc_assert (stmt_ends_bb_p (stmt));
6229 else if (is_gimple_assign (stmt) || is_gimple_call (stmt))
6231 /* In general, assignments with virtual operands are not useful
6232 for deriving ranges, with the obvious exception of calls to
6233 builtin functions. */
6235 if ((is_gimple_call (stmt)
6236 && gimple_call_fndecl (stmt) != NULL_TREE
6237 && DECL_IS_BUILTIN (gimple_call_fndecl (stmt)))
6238 || !gimple_vuse (stmt))
6239 return vrp_visit_assignment_or_call (stmt, output_p);
6241 else if (gimple_code (stmt) == GIMPLE_COND)
6242 return vrp_visit_cond_stmt (stmt, taken_edge_p);
6243 else if (gimple_code (stmt) == GIMPLE_SWITCH)
6244 return vrp_visit_switch_stmt (stmt, taken_edge_p);
6246 /* All other statements produce nothing of interest for VRP, so mark
6247 their outputs varying and prevent further simulation. */
6248 FOR_EACH_SSA_TREE_OPERAND (def, stmt, iter, SSA_OP_DEF)
6249 set_value_range_to_varying (get_value_range (def));
6251 return SSA_PROP_VARYING;
6255 /* Meet operation for value ranges. Given two value ranges VR0 and
6256 VR1, store in VR0 a range that contains both VR0 and VR1. This
6257 may not be the smallest possible such range. */
6260 vrp_meet (value_range_t *vr0, value_range_t *vr1)
6262 if (vr0->type == VR_UNDEFINED)
6264 copy_value_range (vr0, vr1);
6268 if (vr1->type == VR_UNDEFINED)
6270 /* Nothing to do. VR0 already has the resulting range. */
6274 if (vr0->type == VR_VARYING)
6276 /* Nothing to do. VR0 already has the resulting range. */
6280 if (vr1->type == VR_VARYING)
6282 set_value_range_to_varying (vr0);
6286 if (vr0->type == VR_RANGE && vr1->type == VR_RANGE)
6291 /* Compute the convex hull of the ranges. The lower limit of
6292 the new range is the minimum of the two ranges. If they
6293 cannot be compared, then give up. */
6294 cmp = compare_values (vr0->min, vr1->min);
6295 if (cmp == 0 || cmp == 1)
6302 /* Similarly, the upper limit of the new range is the maximum
6303 of the two ranges. If they cannot be compared, then
6305 cmp = compare_values (vr0->max, vr1->max);
6306 if (cmp == 0 || cmp == -1)
6313 /* Check for useless ranges. */
6314 if (INTEGRAL_TYPE_P (TREE_TYPE (min))
6315 && ((vrp_val_is_min (min) || is_overflow_infinity (min))
6316 && (vrp_val_is_max (max) || is_overflow_infinity (max))))
6319 /* The resulting set of equivalences is the intersection of
6321 if (vr0->equiv && vr1->equiv && vr0->equiv != vr1->equiv)
6322 bitmap_and_into (vr0->equiv, vr1->equiv);
6323 else if (vr0->equiv && !vr1->equiv)
6324 bitmap_clear (vr0->equiv);
6326 set_value_range (vr0, vr0->type, min, max, vr0->equiv);
6328 else if (vr0->type == VR_ANTI_RANGE && vr1->type == VR_ANTI_RANGE)
6330 /* Two anti-ranges meet only if their complements intersect.
6331 Only handle the case of identical ranges. */
6332 if (compare_values (vr0->min, vr1->min) == 0
6333 && compare_values (vr0->max, vr1->max) == 0
6334 && compare_values (vr0->min, vr0->max) == 0)
6336 /* The resulting set of equivalences is the intersection of
6338 if (vr0->equiv && vr1->equiv && vr0->equiv != vr1->equiv)
6339 bitmap_and_into (vr0->equiv, vr1->equiv);
6340 else if (vr0->equiv && !vr1->equiv)
6341 bitmap_clear (vr0->equiv);
6346 else if (vr0->type == VR_ANTI_RANGE || vr1->type == VR_ANTI_RANGE)
6348 /* For a numeric range [VAL1, VAL2] and an anti-range ~[VAL3, VAL4],
6349 only handle the case where the ranges have an empty intersection.
6350 The result of the meet operation is the anti-range. */
6351 if (!symbolic_range_p (vr0)
6352 && !symbolic_range_p (vr1)
6353 && !value_ranges_intersect_p (vr0, vr1))
6355 /* Copy most of VR1 into VR0. Don't copy VR1's equivalence
6356 set. We need to compute the intersection of the two
6357 equivalence sets. */
6358 if (vr1->type == VR_ANTI_RANGE)
6359 set_value_range (vr0, vr1->type, vr1->min, vr1->max, vr0->equiv);
6361 /* The resulting set of equivalences is the intersection of
6363 if (vr0->equiv && vr1->equiv && vr0->equiv != vr1->equiv)
6364 bitmap_and_into (vr0->equiv, vr1->equiv);
6365 else if (vr0->equiv && !vr1->equiv)
6366 bitmap_clear (vr0->equiv);
6377 /* Failed to find an efficient meet. Before giving up and setting
6378 the result to VARYING, see if we can at least derive a useful
6379 anti-range. FIXME, all this nonsense about distinguishing
6380 anti-ranges from ranges is necessary because of the odd
6381 semantics of range_includes_zero_p and friends. */
6382 if (!symbolic_range_p (vr0)
6383 && ((vr0->type == VR_RANGE && !range_includes_zero_p (vr0))
6384 || (vr0->type == VR_ANTI_RANGE && range_includes_zero_p (vr0)))
6385 && !symbolic_range_p (vr1)
6386 && ((vr1->type == VR_RANGE && !range_includes_zero_p (vr1))
6387 || (vr1->type == VR_ANTI_RANGE && range_includes_zero_p (vr1))))
6389 set_value_range_to_nonnull (vr0, TREE_TYPE (vr0->min));
6391 /* Since this meet operation did not result from the meeting of
6392 two equivalent names, VR0 cannot have any equivalences. */
6394 bitmap_clear (vr0->equiv);
6397 set_value_range_to_varying (vr0);
6401 /* Visit all arguments for PHI node PHI that flow through executable
6402 edges. If a valid value range can be derived from all the incoming
6403 value ranges, set a new range for the LHS of PHI. */
6405 static enum ssa_prop_result
6406 vrp_visit_phi_node (gimple phi)
6409 tree lhs = PHI_RESULT (phi);
6410 value_range_t *lhs_vr = get_value_range (lhs);
6411 value_range_t vr_result = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
6412 int edges, old_edges;
6415 copy_value_range (&vr_result, lhs_vr);
6417 if (dump_file && (dump_flags & TDF_DETAILS))
6419 fprintf (dump_file, "\nVisiting PHI node: ");
6420 print_gimple_stmt (dump_file, phi, 0, dump_flags);
6424 for (i = 0; i < gimple_phi_num_args (phi); i++)
6426 edge e = gimple_phi_arg_edge (phi, i);
6428 if (dump_file && (dump_flags & TDF_DETAILS))
6431 "\n Argument #%d (%d -> %d %sexecutable)\n",
6432 (int) i, e->src->index, e->dest->index,
6433 (e->flags & EDGE_EXECUTABLE) ? "" : "not ");
6436 if (e->flags & EDGE_EXECUTABLE)
6438 tree arg = PHI_ARG_DEF (phi, i);
6439 value_range_t vr_arg;
6443 if (TREE_CODE (arg) == SSA_NAME)
6445 vr_arg = *(get_value_range (arg));
6449 if (is_overflow_infinity (arg))
6451 arg = copy_node (arg);
6452 TREE_OVERFLOW (arg) = 0;
6455 vr_arg.type = VR_RANGE;
6458 vr_arg.equiv = NULL;
6461 if (dump_file && (dump_flags & TDF_DETAILS))
6463 fprintf (dump_file, "\t");
6464 print_generic_expr (dump_file, arg, dump_flags);
6465 fprintf (dump_file, "\n\tValue: ");
6466 dump_value_range (dump_file, &vr_arg);
6467 fprintf (dump_file, "\n");
6470 vrp_meet (&vr_result, &vr_arg);
6472 if (vr_result.type == VR_VARYING)
6477 /* If this is a loop PHI node SCEV may known more about its
6480 && (l = loop_containing_stmt (phi))
6481 && l->header == gimple_bb (phi))
6482 adjust_range_with_scev (&vr_result, l, phi, lhs);
6484 if (vr_result.type == VR_VARYING)
6487 old_edges = vr_phi_edge_counts[SSA_NAME_VERSION (lhs)];
6488 vr_phi_edge_counts[SSA_NAME_VERSION (lhs)] = edges;
6490 /* To prevent infinite iterations in the algorithm, derive ranges
6491 when the new value is slightly bigger or smaller than the
6492 previous one. We don't do this if we have seen a new executable
6493 edge; this helps us avoid an overflow infinity for conditionals
6494 which are not in a loop. */
6495 if (lhs_vr->type == VR_RANGE && vr_result.type == VR_RANGE
6496 && edges <= old_edges)
6498 if (!POINTER_TYPE_P (TREE_TYPE (lhs)))
6500 int cmp_min = compare_values (lhs_vr->min, vr_result.min);
6501 int cmp_max = compare_values (lhs_vr->max, vr_result.max);
6503 /* If the new minimum is smaller or larger than the previous
6504 one, go all the way to -INF. In the first case, to avoid
6505 iterating millions of times to reach -INF, and in the
6506 other case to avoid infinite bouncing between different
6508 if (cmp_min > 0 || cmp_min < 0)
6510 /* If we will end up with a (-INF, +INF) range, set it to
6511 VARYING. Same if the previous max value was invalid for
6512 the type and we'd end up with vr_result.min > vr_result.max. */
6513 if (vrp_val_is_max (vr_result.max)
6514 || compare_values (TYPE_MIN_VALUE (TREE_TYPE (vr_result.min)),
6518 if (!needs_overflow_infinity (TREE_TYPE (vr_result.min))
6519 || !vrp_var_may_overflow (lhs, phi))
6520 vr_result.min = TYPE_MIN_VALUE (TREE_TYPE (vr_result.min));
6521 else if (supports_overflow_infinity (TREE_TYPE (vr_result.min)))
6523 negative_overflow_infinity (TREE_TYPE (vr_result.min));
6528 /* Similarly, if the new maximum is smaller or larger than
6529 the previous one, go all the way to +INF. */
6530 if (cmp_max < 0 || cmp_max > 0)
6532 /* If we will end up with a (-INF, +INF) range, set it to
6533 VARYING. Same if the previous min value was invalid for
6534 the type and we'd end up with vr_result.max < vr_result.min. */
6535 if (vrp_val_is_min (vr_result.min)
6536 || compare_values (TYPE_MAX_VALUE (TREE_TYPE (vr_result.max)),
6540 if (!needs_overflow_infinity (TREE_TYPE (vr_result.max))
6541 || !vrp_var_may_overflow (lhs, phi))
6542 vr_result.max = TYPE_MAX_VALUE (TREE_TYPE (vr_result.max));
6543 else if (supports_overflow_infinity (TREE_TYPE (vr_result.max)))
6545 positive_overflow_infinity (TREE_TYPE (vr_result.max));
6552 /* If the new range is different than the previous value, keep
6554 if (update_value_range (lhs, &vr_result))
6556 if (dump_file && (dump_flags & TDF_DETAILS))
6558 fprintf (dump_file, "Found new range for ");
6559 print_generic_expr (dump_file, lhs, 0);
6560 fprintf (dump_file, ": ");
6561 dump_value_range (dump_file, &vr_result);
6562 fprintf (dump_file, "\n\n");
6565 return SSA_PROP_INTERESTING;
6568 /* Nothing changed, don't add outgoing edges. */
6569 return SSA_PROP_NOT_INTERESTING;
6571 /* No match found. Set the LHS to VARYING. */
6573 set_value_range_to_varying (lhs_vr);
6574 return SSA_PROP_VARYING;
6577 /* Simplify boolean operations if the source is known
6578 to be already a boolean. */
6580 simplify_truth_ops_using_ranges (gimple_stmt_iterator *gsi, gimple stmt)
6582 enum tree_code rhs_code = gimple_assign_rhs_code (stmt);
6587 bool need_conversion;
6589 op0 = gimple_assign_rhs1 (stmt);
6590 if (TYPE_PRECISION (TREE_TYPE (op0)) != 1)
6592 if (TREE_CODE (op0) != SSA_NAME)
6594 vr = get_value_range (op0);
6596 val = compare_range_with_value (GE_EXPR, vr, integer_zero_node, &sop);
6597 if (!val || !integer_onep (val))
6600 val = compare_range_with_value (LE_EXPR, vr, integer_one_node, &sop);
6601 if (!val || !integer_onep (val))
6605 if (rhs_code == TRUTH_NOT_EXPR)
6608 op1 = build_int_cst (TREE_TYPE (op0), 1);
6612 op1 = gimple_assign_rhs2 (stmt);
6614 /* Reduce number of cases to handle. */
6615 if (is_gimple_min_invariant (op1))
6617 /* Exclude anything that should have been already folded. */
6618 if (rhs_code != EQ_EXPR
6619 && rhs_code != NE_EXPR
6620 && rhs_code != TRUTH_XOR_EXPR)
6623 if (!integer_zerop (op1)
6624 && !integer_onep (op1)
6625 && !integer_all_onesp (op1))
6628 /* Limit the number of cases we have to consider. */
6629 if (rhs_code == EQ_EXPR)
6632 op1 = fold_unary (TRUTH_NOT_EXPR, TREE_TYPE (op1), op1);
6637 /* Punt on A == B as there is no BIT_XNOR_EXPR. */
6638 if (rhs_code == EQ_EXPR)
6641 if (TYPE_PRECISION (TREE_TYPE (op1)) != 1)
6643 vr = get_value_range (op1);
6644 val = compare_range_with_value (GE_EXPR, vr, integer_zero_node, &sop);
6645 if (!val || !integer_onep (val))
6648 val = compare_range_with_value (LE_EXPR, vr, integer_one_node, &sop);
6649 if (!val || !integer_onep (val))
6655 if (sop && issue_strict_overflow_warning (WARN_STRICT_OVERFLOW_MISC))
6657 location_t location;
6659 if (!gimple_has_location (stmt))
6660 location = input_location;
6662 location = gimple_location (stmt);
6664 if (rhs_code == TRUTH_AND_EXPR || rhs_code == TRUTH_OR_EXPR)
6665 warning_at (location, OPT_Wstrict_overflow,
6666 _("assuming signed overflow does not occur when "
6667 "simplifying && or || to & or |"));
6669 warning_at (location, OPT_Wstrict_overflow,
6670 _("assuming signed overflow does not occur when "
6671 "simplifying ==, != or ! to identity or ^"));
6675 !useless_type_conversion_p (TREE_TYPE (gimple_assign_lhs (stmt)),
6678 /* Make sure to not sign-extend -1 as a boolean value. */
6680 && !TYPE_UNSIGNED (TREE_TYPE (op0))
6681 && TYPE_PRECISION (TREE_TYPE (op0)) == 1)
6686 case TRUTH_AND_EXPR:
6687 rhs_code = BIT_AND_EXPR;
6690 rhs_code = BIT_IOR_EXPR;
6692 case TRUTH_XOR_EXPR:
6694 if (integer_zerop (op1))
6696 gimple_assign_set_rhs_with_ops (gsi,
6697 need_conversion ? NOP_EXPR : SSA_NAME,
6699 update_stmt (gsi_stmt (*gsi));
6703 rhs_code = BIT_XOR_EXPR;
6709 if (need_conversion)
6712 gimple_assign_set_rhs_with_ops (gsi, rhs_code, op0, op1);
6713 update_stmt (gsi_stmt (*gsi));
6717 /* Simplify a division or modulo operator to a right shift or
6718 bitwise and if the first operand is unsigned or is greater
6719 than zero and the second operand is an exact power of two. */
6722 simplify_div_or_mod_using_ranges (gimple stmt)
6724 enum tree_code rhs_code = gimple_assign_rhs_code (stmt);
6726 tree op0 = gimple_assign_rhs1 (stmt);
6727 tree op1 = gimple_assign_rhs2 (stmt);
6728 value_range_t *vr = get_value_range (gimple_assign_rhs1 (stmt));
6730 if (TYPE_UNSIGNED (TREE_TYPE (op0)))
6732 val = integer_one_node;
6738 val = compare_range_with_value (GE_EXPR, vr, integer_zero_node, &sop);
6742 && integer_onep (val)
6743 && issue_strict_overflow_warning (WARN_STRICT_OVERFLOW_MISC))
6745 location_t location;
6747 if (!gimple_has_location (stmt))
6748 location = input_location;
6750 location = gimple_location (stmt);
6751 warning_at (location, OPT_Wstrict_overflow,
6752 "assuming signed overflow does not occur when "
6753 "simplifying %</%> or %<%%%> to %<>>%> or %<&%>");
6757 if (val && integer_onep (val))
6761 if (rhs_code == TRUNC_DIV_EXPR)
6763 t = build_int_cst (NULL_TREE, tree_log2 (op1));
6764 gimple_assign_set_rhs_code (stmt, RSHIFT_EXPR);
6765 gimple_assign_set_rhs1 (stmt, op0);
6766 gimple_assign_set_rhs2 (stmt, t);
6770 t = build_int_cst (TREE_TYPE (op1), 1);
6771 t = int_const_binop (MINUS_EXPR, op1, t, 0);
6772 t = fold_convert (TREE_TYPE (op0), t);
6774 gimple_assign_set_rhs_code (stmt, BIT_AND_EXPR);
6775 gimple_assign_set_rhs1 (stmt, op0);
6776 gimple_assign_set_rhs2 (stmt, t);
6786 /* If the operand to an ABS_EXPR is >= 0, then eliminate the
6787 ABS_EXPR. If the operand is <= 0, then simplify the
6788 ABS_EXPR into a NEGATE_EXPR. */
6791 simplify_abs_using_ranges (gimple stmt)
6794 tree op = gimple_assign_rhs1 (stmt);
6795 tree type = TREE_TYPE (op);
6796 value_range_t *vr = get_value_range (op);
6798 if (TYPE_UNSIGNED (type))
6800 val = integer_zero_node;
6806 val = compare_range_with_value (LE_EXPR, vr, integer_zero_node, &sop);
6810 val = compare_range_with_value (GE_EXPR, vr, integer_zero_node,
6815 if (integer_zerop (val))
6816 val = integer_one_node;
6817 else if (integer_onep (val))
6818 val = integer_zero_node;
6823 && (integer_onep (val) || integer_zerop (val)))
6825 if (sop && issue_strict_overflow_warning (WARN_STRICT_OVERFLOW_MISC))
6827 location_t location;
6829 if (!gimple_has_location (stmt))
6830 location = input_location;
6832 location = gimple_location (stmt);
6833 warning_at (location, OPT_Wstrict_overflow,
6834 "assuming signed overflow does not occur when "
6835 "simplifying %<abs (X)%> to %<X%> or %<-X%>");
6838 gimple_assign_set_rhs1 (stmt, op);
6839 if (integer_onep (val))
6840 gimple_assign_set_rhs_code (stmt, NEGATE_EXPR);
6842 gimple_assign_set_rhs_code (stmt, SSA_NAME);
6851 /* We are comparing trees OP0 and OP1 using COND_CODE. OP0 has
6852 a known value range VR.
6854 If there is one and only one value which will satisfy the
6855 conditional, then return that value. Else return NULL. */
6858 test_for_singularity (enum tree_code cond_code, tree op0,
6859 tree op1, value_range_t *vr)
6864 /* Extract minimum/maximum values which satisfy the
6865 the conditional as it was written. */
6866 if (cond_code == LE_EXPR || cond_code == LT_EXPR)
6868 /* This should not be negative infinity; there is no overflow
6870 min = TYPE_MIN_VALUE (TREE_TYPE (op0));
6873 if (cond_code == LT_EXPR && !is_overflow_infinity (max))
6875 tree one = build_int_cst (TREE_TYPE (op0), 1);
6876 max = fold_build2 (MINUS_EXPR, TREE_TYPE (op0), max, one);
6878 TREE_NO_WARNING (max) = 1;
6881 else if (cond_code == GE_EXPR || cond_code == GT_EXPR)
6883 /* This should not be positive infinity; there is no overflow
6885 max = TYPE_MAX_VALUE (TREE_TYPE (op0));
6888 if (cond_code == GT_EXPR && !is_overflow_infinity (min))
6890 tree one = build_int_cst (TREE_TYPE (op0), 1);
6891 min = fold_build2 (PLUS_EXPR, TREE_TYPE (op0), min, one);
6893 TREE_NO_WARNING (min) = 1;
6897 /* Now refine the minimum and maximum values using any
6898 value range information we have for op0. */
6901 if (compare_values (vr->min, min) == 1)
6903 if (compare_values (vr->max, max) == -1)
6906 /* If the new min/max values have converged to a single value,
6907 then there is only one value which can satisfy the condition,
6908 return that value. */
6909 if (operand_equal_p (min, max, 0) && is_gimple_min_invariant (min))
6915 /* Simplify a conditional using a relational operator to an equality
6916 test if the range information indicates only one value can satisfy
6917 the original conditional. */
6920 simplify_cond_using_ranges (gimple stmt)
6922 tree op0 = gimple_cond_lhs (stmt);
6923 tree op1 = gimple_cond_rhs (stmt);
6924 enum tree_code cond_code = gimple_cond_code (stmt);
6926 if (cond_code != NE_EXPR
6927 && cond_code != EQ_EXPR
6928 && TREE_CODE (op0) == SSA_NAME
6929 && INTEGRAL_TYPE_P (TREE_TYPE (op0))
6930 && is_gimple_min_invariant (op1))
6932 value_range_t *vr = get_value_range (op0);
6934 /* If we have range information for OP0, then we might be
6935 able to simplify this conditional. */
6936 if (vr->type == VR_RANGE)
6938 tree new_tree = test_for_singularity (cond_code, op0, op1, vr);
6944 fprintf (dump_file, "Simplified relational ");
6945 print_gimple_stmt (dump_file, stmt, 0, 0);
6946 fprintf (dump_file, " into ");
6949 gimple_cond_set_code (stmt, EQ_EXPR);
6950 gimple_cond_set_lhs (stmt, op0);
6951 gimple_cond_set_rhs (stmt, new_tree);
6957 print_gimple_stmt (dump_file, stmt, 0, 0);
6958 fprintf (dump_file, "\n");
6964 /* Try again after inverting the condition. We only deal
6965 with integral types here, so no need to worry about
6966 issues with inverting FP comparisons. */
6967 cond_code = invert_tree_comparison (cond_code, false);
6968 new_tree = test_for_singularity (cond_code, op0, op1, vr);
6974 fprintf (dump_file, "Simplified relational ");
6975 print_gimple_stmt (dump_file, stmt, 0, 0);
6976 fprintf (dump_file, " into ");
6979 gimple_cond_set_code (stmt, NE_EXPR);
6980 gimple_cond_set_lhs (stmt, op0);
6981 gimple_cond_set_rhs (stmt, new_tree);
6987 print_gimple_stmt (dump_file, stmt, 0, 0);
6988 fprintf (dump_file, "\n");
6999 /* Simplify a switch statement using the value range of the switch
7003 simplify_switch_using_ranges (gimple stmt)
7005 tree op = gimple_switch_index (stmt);
7010 size_t i = 0, j = 0, n, n2;
7014 if (TREE_CODE (op) == SSA_NAME)
7016 vr = get_value_range (op);
7018 /* We can only handle integer ranges. */
7019 if (vr->type != VR_RANGE
7020 || symbolic_range_p (vr))
7023 /* Find case label for min/max of the value range. */
7024 take_default = !find_case_label_range (stmt, vr->min, vr->max, &i, &j);
7026 else if (TREE_CODE (op) == INTEGER_CST)
7028 take_default = !find_case_label_index (stmt, 1, op, &i);
7042 n = gimple_switch_num_labels (stmt);
7044 /* Bail out if this is just all edges taken. */
7050 /* Build a new vector of taken case labels. */
7051 vec2 = make_tree_vec (j - i + 1 + (int)take_default);
7054 /* Add the default edge, if necessary. */
7056 TREE_VEC_ELT (vec2, n2++) = gimple_switch_default_label (stmt);
7058 for (; i <= j; ++i, ++n2)
7059 TREE_VEC_ELT (vec2, n2) = gimple_switch_label (stmt, i);
7061 /* Mark needed edges. */
7062 for (i = 0; i < n2; ++i)
7064 e = find_edge (gimple_bb (stmt),
7065 label_to_block (CASE_LABEL (TREE_VEC_ELT (vec2, i))));
7066 e->aux = (void *)-1;
7069 /* Queue not needed edges for later removal. */
7070 FOR_EACH_EDGE (e, ei, gimple_bb (stmt)->succs)
7072 if (e->aux == (void *)-1)
7078 if (dump_file && (dump_flags & TDF_DETAILS))
7080 fprintf (dump_file, "removing unreachable case label\n");
7082 VEC_safe_push (edge, heap, to_remove_edges, e);
7083 e->flags &= ~EDGE_EXECUTABLE;
7086 /* And queue an update for the stmt. */
7089 VEC_safe_push (switch_update, heap, to_update_switch_stmts, &su);
7093 /* Simplify STMT using ranges if possible. */
7096 simplify_stmt_using_ranges (gimple_stmt_iterator *gsi)
7098 gimple stmt = gsi_stmt (*gsi);
7099 if (is_gimple_assign (stmt))
7101 enum tree_code rhs_code = gimple_assign_rhs_code (stmt);
7107 case TRUTH_NOT_EXPR:
7108 case TRUTH_AND_EXPR:
7110 case TRUTH_XOR_EXPR:
7111 /* Transform EQ_EXPR, NE_EXPR, TRUTH_NOT_EXPR into BIT_XOR_EXPR
7112 or identity if the RHS is zero or one, and the LHS are known
7113 to be boolean values. Transform all TRUTH_*_EXPR into
7114 BIT_*_EXPR if both arguments are known to be boolean values. */
7115 if (INTEGRAL_TYPE_P (TREE_TYPE (gimple_assign_rhs1 (stmt))))
7116 return simplify_truth_ops_using_ranges (gsi, stmt);
7119 /* Transform TRUNC_DIV_EXPR and TRUNC_MOD_EXPR into RSHIFT_EXPR
7120 and BIT_AND_EXPR respectively if the first operand is greater
7121 than zero and the second operand is an exact power of two. */
7122 case TRUNC_DIV_EXPR:
7123 case TRUNC_MOD_EXPR:
7124 if (INTEGRAL_TYPE_P (TREE_TYPE (gimple_assign_rhs1 (stmt)))
7125 && integer_pow2p (gimple_assign_rhs2 (stmt)))
7126 return simplify_div_or_mod_using_ranges (stmt);
7129 /* Transform ABS (X) into X or -X as appropriate. */
7131 if (TREE_CODE (gimple_assign_rhs1 (stmt)) == SSA_NAME
7132 && INTEGRAL_TYPE_P (TREE_TYPE (gimple_assign_rhs1 (stmt))))
7133 return simplify_abs_using_ranges (stmt);
7140 else if (gimple_code (stmt) == GIMPLE_COND)
7141 return simplify_cond_using_ranges (stmt);
7142 else if (gimple_code (stmt) == GIMPLE_SWITCH)
7143 return simplify_switch_using_ranges (stmt);
7148 /* If the statement pointed by SI has a predicate whose value can be
7149 computed using the value range information computed by VRP, compute
7150 its value and return true. Otherwise, return false. */
7153 fold_predicate_in (gimple_stmt_iterator *si)
7155 bool assignment_p = false;
7157 gimple stmt = gsi_stmt (*si);
7159 if (is_gimple_assign (stmt)
7160 && TREE_CODE_CLASS (gimple_assign_rhs_code (stmt)) == tcc_comparison)
7162 assignment_p = true;
7163 val = vrp_evaluate_conditional (gimple_assign_rhs_code (stmt),
7164 gimple_assign_rhs1 (stmt),
7165 gimple_assign_rhs2 (stmt),
7168 else if (gimple_code (stmt) == GIMPLE_COND)
7169 val = vrp_evaluate_conditional (gimple_cond_code (stmt),
7170 gimple_cond_lhs (stmt),
7171 gimple_cond_rhs (stmt),
7179 val = fold_convert (gimple_expr_type (stmt), val);
7183 fprintf (dump_file, "Folding predicate ");
7184 print_gimple_expr (dump_file, stmt, 0, 0);
7185 fprintf (dump_file, " to ");
7186 print_generic_expr (dump_file, val, 0);
7187 fprintf (dump_file, "\n");
7190 if (is_gimple_assign (stmt))
7191 gimple_assign_set_rhs_from_tree (si, val);
7194 gcc_assert (gimple_code (stmt) == GIMPLE_COND);
7195 if (integer_zerop (val))
7196 gimple_cond_make_false (stmt);
7197 else if (integer_onep (val))
7198 gimple_cond_make_true (stmt);
7209 /* Callback for substitute_and_fold folding the stmt at *SI. */
7212 vrp_fold_stmt (gimple_stmt_iterator *si)
7214 if (fold_predicate_in (si))
7217 return simplify_stmt_using_ranges (si);
7220 /* Stack of dest,src equivalency pairs that need to be restored after
7221 each attempt to thread a block's incoming edge to an outgoing edge.
7223 A NULL entry is used to mark the end of pairs which need to be
7225 static VEC(tree,heap) *stack;
7227 /* A trivial wrapper so that we can present the generic jump threading
7228 code with a simple API for simplifying statements. STMT is the
7229 statement we want to simplify, WITHIN_STMT provides the location
7230 for any overflow warnings. */
7233 simplify_stmt_for_jump_threading (gimple stmt, gimple within_stmt)
7235 /* We only use VRP information to simplify conditionals. This is
7236 overly conservative, but it's unclear if doing more would be
7237 worth the compile time cost. */
7238 if (gimple_code (stmt) != GIMPLE_COND)
7241 return vrp_evaluate_conditional (gimple_cond_code (stmt),
7242 gimple_cond_lhs (stmt),
7243 gimple_cond_rhs (stmt), within_stmt);
7246 /* Blocks which have more than one predecessor and more than
7247 one successor present jump threading opportunities, i.e.,
7248 when the block is reached from a specific predecessor, we
7249 may be able to determine which of the outgoing edges will
7250 be traversed. When this optimization applies, we are able
7251 to avoid conditionals at runtime and we may expose secondary
7252 optimization opportunities.
7254 This routine is effectively a driver for the generic jump
7255 threading code. It basically just presents the generic code
7256 with edges that may be suitable for jump threading.
7258 Unlike DOM, we do not iterate VRP if jump threading was successful.
7259 While iterating may expose new opportunities for VRP, it is expected
7260 those opportunities would be very limited and the compile time cost
7261 to expose those opportunities would be significant.
7263 As jump threading opportunities are discovered, they are registered
7264 for later realization. */
7267 identify_jump_threads (void)
7274 /* Ugh. When substituting values earlier in this pass we can
7275 wipe the dominance information. So rebuild the dominator
7276 information as we need it within the jump threading code. */
7277 calculate_dominance_info (CDI_DOMINATORS);
7279 /* We do not allow VRP information to be used for jump threading
7280 across a back edge in the CFG. Otherwise it becomes too
7281 difficult to avoid eliminating loop exit tests. Of course
7282 EDGE_DFS_BACK is not accurate at this time so we have to
7284 mark_dfs_back_edges ();
7286 /* Do not thread across edges we are about to remove. Just marking
7287 them as EDGE_DFS_BACK will do. */
7288 for (i = 0; VEC_iterate (edge, to_remove_edges, i, e); ++i)
7289 e->flags |= EDGE_DFS_BACK;
7291 /* Allocate our unwinder stack to unwind any temporary equivalences
7292 that might be recorded. */
7293 stack = VEC_alloc (tree, heap, 20);
7295 /* To avoid lots of silly node creation, we create a single
7296 conditional and just modify it in-place when attempting to
7298 dummy = gimple_build_cond (EQ_EXPR,
7299 integer_zero_node, integer_zero_node,
7302 /* Walk through all the blocks finding those which present a
7303 potential jump threading opportunity. We could set this up
7304 as a dominator walker and record data during the walk, but
7305 I doubt it's worth the effort for the classes of jump
7306 threading opportunities we are trying to identify at this
7307 point in compilation. */
7312 /* If the generic jump threading code does not find this block
7313 interesting, then there is nothing to do. */
7314 if (! potentially_threadable_block (bb))
7317 /* We only care about blocks ending in a COND_EXPR. While there
7318 may be some value in handling SWITCH_EXPR here, I doubt it's
7319 terribly important. */
7320 last = gsi_stmt (gsi_last_bb (bb));
7321 if (gimple_code (last) != GIMPLE_COND)
7324 /* We're basically looking for any kind of conditional with
7325 integral type arguments. */
7326 if (TREE_CODE (gimple_cond_lhs (last)) == SSA_NAME
7327 && INTEGRAL_TYPE_P (TREE_TYPE (gimple_cond_lhs (last)))
7328 && (TREE_CODE (gimple_cond_rhs (last)) == SSA_NAME
7329 || is_gimple_min_invariant (gimple_cond_rhs (last)))
7330 && INTEGRAL_TYPE_P (TREE_TYPE (gimple_cond_rhs (last))))
7334 /* We've got a block with multiple predecessors and multiple
7335 successors which also ends in a suitable conditional. For
7336 each predecessor, see if we can thread it to a specific
7338 FOR_EACH_EDGE (e, ei, bb->preds)
7340 /* Do not thread across back edges or abnormal edges
7342 if (e->flags & (EDGE_DFS_BACK | EDGE_COMPLEX))
7345 thread_across_edge (dummy, e, true, &stack,
7346 simplify_stmt_for_jump_threading);
7351 /* We do not actually update the CFG or SSA graphs at this point as
7352 ASSERT_EXPRs are still in the IL and cfg cleanup code does not yet
7353 handle ASSERT_EXPRs gracefully. */
7356 /* We identified all the jump threading opportunities earlier, but could
7357 not transform the CFG at that time. This routine transforms the
7358 CFG and arranges for the dominator tree to be rebuilt if necessary.
7360 Note the SSA graph update will occur during the normal TODO
7361 processing by the pass manager. */
7363 finalize_jump_threads (void)
7365 thread_through_all_blocks (false);
7366 VEC_free (tree, heap, stack);
7370 /* Traverse all the blocks folding conditionals with known ranges. */
7376 prop_value_t *single_val_range;
7377 bool do_value_subst_p;
7378 unsigned num = num_ssa_names;
7382 fprintf (dump_file, "\nValue ranges after VRP:\n\n");
7383 dump_all_value_ranges (dump_file);
7384 fprintf (dump_file, "\n");
7387 /* We may have ended with ranges that have exactly one value. Those
7388 values can be substituted as any other const propagated
7389 value using substitute_and_fold. */
7390 single_val_range = XCNEWVEC (prop_value_t, num);
7392 do_value_subst_p = false;
7393 for (i = 0; i < num; i++)
7395 && vr_value[i]->type == VR_RANGE
7396 && vr_value[i]->min == vr_value[i]->max
7397 && is_gimple_min_invariant (vr_value[i]->min))
7399 single_val_range[i].value = vr_value[i]->min;
7400 do_value_subst_p = true;
7403 if (!do_value_subst_p)
7405 /* We found no single-valued ranges, don't waste time trying to
7406 do single value substitution in substitute_and_fold. */
7407 free (single_val_range);
7408 single_val_range = NULL;
7411 substitute_and_fold (single_val_range, vrp_fold_stmt, false);
7413 if (warn_array_bounds)
7414 check_all_array_refs ();
7416 /* We must identify jump threading opportunities before we release
7417 the datastructures built by VRP. */
7418 identify_jump_threads ();
7420 /* Free allocated memory. */
7421 for (i = 0; i < num; i++)
7424 BITMAP_FREE (vr_value[i]->equiv);
7428 free (single_val_range);
7430 free (vr_phi_edge_counts);
7432 /* So that we can distinguish between VRP data being available
7433 and not available. */
7435 vr_phi_edge_counts = NULL;
7439 /* Main entry point to VRP (Value Range Propagation). This pass is
7440 loosely based on J. R. C. Patterson, ``Accurate Static Branch
7441 Prediction by Value Range Propagation,'' in SIGPLAN Conference on
7442 Programming Language Design and Implementation, pp. 67-78, 1995.
7443 Also available at http://citeseer.ist.psu.edu/patterson95accurate.html
7445 This is essentially an SSA-CCP pass modified to deal with ranges
7446 instead of constants.
7448 While propagating ranges, we may find that two or more SSA name
7449 have equivalent, though distinct ranges. For instance,
7452 2 p_4 = ASSERT_EXPR <p_3, p_3 != 0>
7454 4 p_5 = ASSERT_EXPR <p_4, p_4 == q_2>;
7458 In the code above, pointer p_5 has range [q_2, q_2], but from the
7459 code we can also determine that p_5 cannot be NULL and, if q_2 had
7460 a non-varying range, p_5's range should also be compatible with it.
7462 These equivalences are created by two expressions: ASSERT_EXPR and
7463 copy operations. Since p_5 is an assertion on p_4, and p_4 was the
7464 result of another assertion, then we can use the fact that p_5 and
7465 p_4 are equivalent when evaluating p_5's range.
7467 Together with value ranges, we also propagate these equivalences
7468 between names so that we can take advantage of information from
7469 multiple ranges when doing final replacement. Note that this
7470 equivalency relation is transitive but not symmetric.
7472 In the example above, p_5 is equivalent to p_4, q_2 and p_3, but we
7473 cannot assert that q_2 is equivalent to p_5 because q_2 may be used
7474 in contexts where that assertion does not hold (e.g., in line 6).
7476 TODO, the main difference between this pass and Patterson's is that
7477 we do not propagate edge probabilities. We only compute whether
7478 edges can be taken or not. That is, instead of having a spectrum
7479 of jump probabilities between 0 and 1, we only deal with 0, 1 and
7480 DON'T KNOW. In the future, it may be worthwhile to propagate
7481 probabilities to aid branch prediction. */
7490 loop_optimizer_init (LOOPS_NORMAL | LOOPS_HAVE_RECORDED_EXITS);
7491 rewrite_into_loop_closed_ssa (NULL, TODO_update_ssa);
7494 insert_range_assertions ();
7496 to_remove_edges = VEC_alloc (edge, heap, 10);
7497 to_update_switch_stmts = VEC_alloc (switch_update, heap, 5);
7498 threadedge_initialize_values ();
7501 ssa_propagate (vrp_visit_stmt, vrp_visit_phi_node);
7504 /* ASSERT_EXPRs must be removed before finalizing jump threads
7505 as finalizing jump threads calls the CFG cleanup code which
7506 does not properly handle ASSERT_EXPRs. */
7507 remove_range_assertions ();
7509 /* If we exposed any new variables, go ahead and put them into
7510 SSA form now, before we handle jump threading. This simplifies
7511 interactions between rewriting of _DECL nodes into SSA form
7512 and rewriting SSA_NAME nodes into SSA form after block
7513 duplication and CFG manipulation. */
7514 update_ssa (TODO_update_ssa);
7516 finalize_jump_threads ();
7518 /* Remove dead edges from SWITCH_EXPR optimization. This leaves the
7519 CFG in a broken state and requires a cfg_cleanup run. */
7520 for (i = 0; VEC_iterate (edge, to_remove_edges, i, e); ++i)
7522 /* Update SWITCH_EXPR case label vector. */
7523 for (i = 0; VEC_iterate (switch_update, to_update_switch_stmts, i, su); ++i)
7526 size_t n = TREE_VEC_LENGTH (su->vec);
7528 gimple_switch_set_num_labels (su->stmt, n);
7529 for (j = 0; j < n; j++)
7530 gimple_switch_set_label (su->stmt, j, TREE_VEC_ELT (su->vec, j));
7531 /* As we may have replaced the default label with a regular one
7532 make sure to make it a real default label again. This ensures
7533 optimal expansion. */
7534 label = gimple_switch_default_label (su->stmt);
7535 CASE_LOW (label) = NULL_TREE;
7536 CASE_HIGH (label) = NULL_TREE;
7539 if (VEC_length (edge, to_remove_edges) > 0)
7540 free_dominance_info (CDI_DOMINATORS);
7542 VEC_free (edge, heap, to_remove_edges);
7543 VEC_free (switch_update, heap, to_update_switch_stmts);
7544 threadedge_finalize_values ();
7547 loop_optimizer_finalize ();
7554 return flag_tree_vrp != 0;
7557 struct gimple_opt_pass pass_vrp =
7562 gate_vrp, /* gate */
7563 execute_vrp, /* execute */
7566 0, /* static_pass_number */
7567 TV_TREE_VRP, /* tv_id */
7568 PROP_ssa, /* properties_required */
7569 0, /* properties_provided */
7570 0, /* properties_destroyed */
7571 0, /* todo_flags_start */
7576 | TODO_update_ssa /* todo_flags_finish */