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
= DECL_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 /* For range VR compute two double_int bitmasks. In *MAY_BE_NONZERO
2068 bitmask if some bit is unset, it means for all numbers in the range
2069 the bit is 0, otherwise it might be 0 or 1. In *MUST_BE_NONZERO
2070 bitmask if some bit is set, it means for all numbers in the range
2071 the bit is 1, otherwise it might be 0 or 1. */
2074 zero_nonzero_bits_from_vr (value_range_t
*vr
, double_int
*may_be_nonzero
,
2075 double_int
*must_be_nonzero
)
2077 if (range_int_cst_p (vr
))
2079 if (range_int_cst_singleton_p (vr
))
2081 *may_be_nonzero
= tree_to_double_int (vr
->min
);
2082 *must_be_nonzero
= *may_be_nonzero
;
2085 if (tree_int_cst_sgn (vr
->min
) >= 0)
2087 double_int dmin
= tree_to_double_int (vr
->min
);
2088 double_int dmax
= tree_to_double_int (vr
->max
);
2089 double_int xor_mask
= double_int_xor (dmin
, dmax
);
2090 *may_be_nonzero
= double_int_ior (dmin
, dmax
);
2091 *must_be_nonzero
= double_int_and (dmin
, dmax
);
2092 if (xor_mask
.high
!= 0)
2094 unsigned HOST_WIDE_INT mask
2095 = ((unsigned HOST_WIDE_INT
) 1
2096 << floor_log2 (xor_mask
.high
)) - 1;
2097 may_be_nonzero
->low
= ALL_ONES
;
2098 may_be_nonzero
->high
|= mask
;
2099 must_be_nonzero
->low
= 0;
2100 must_be_nonzero
->high
&= ~mask
;
2102 else if (xor_mask
.low
!= 0)
2104 unsigned HOST_WIDE_INT mask
2105 = ((unsigned HOST_WIDE_INT
) 1
2106 << floor_log2 (xor_mask
.low
)) - 1;
2107 may_be_nonzero
->low
|= mask
;
2108 must_be_nonzero
->low
&= ~mask
;
2113 may_be_nonzero
->low
= ALL_ONES
;
2114 may_be_nonzero
->high
= ALL_ONES
;
2115 must_be_nonzero
->low
= 0;
2116 must_be_nonzero
->high
= 0;
2121 /* Extract range information from a binary expression EXPR based on
2122 the ranges of each of its operands and the expression code. */
2125 extract_range_from_binary_expr (value_range_t
*vr
,
2126 enum tree_code code
,
2127 tree expr_type
, tree op0
, tree op1
)
2129 enum value_range_type type
;
2132 value_range_t vr0
= { VR_UNDEFINED
, NULL_TREE
, NULL_TREE
, NULL
};
2133 value_range_t vr1
= { VR_UNDEFINED
, NULL_TREE
, NULL_TREE
, NULL
};
2135 /* Not all binary expressions can be applied to ranges in a
2136 meaningful way. Handle only arithmetic operations. */
2137 if (code
!= PLUS_EXPR
2138 && code
!= MINUS_EXPR
2139 && code
!= POINTER_PLUS_EXPR
2140 && code
!= MULT_EXPR
2141 && code
!= TRUNC_DIV_EXPR
2142 && code
!= FLOOR_DIV_EXPR
2143 && code
!= CEIL_DIV_EXPR
2144 && code
!= EXACT_DIV_EXPR
2145 && code
!= ROUND_DIV_EXPR
2146 && code
!= TRUNC_MOD_EXPR
2147 && code
!= RSHIFT_EXPR
2150 && code
!= BIT_AND_EXPR
2151 && code
!= BIT_IOR_EXPR
2152 && code
!= TRUTH_AND_EXPR
2153 && code
!= TRUTH_OR_EXPR
)
2155 /* We can still do constant propagation here. */
2156 tree const_op0
= op_with_constant_singleton_value_range (op0
);
2157 tree const_op1
= op_with_constant_singleton_value_range (op1
);
2158 if (const_op0
|| const_op1
)
2160 tree tem
= fold_binary (code
, expr_type
,
2161 const_op0
? const_op0
: op0
,
2162 const_op1
? const_op1
: op1
);
2164 && is_gimple_min_invariant (tem
)
2165 && !is_overflow_infinity (tem
))
2167 set_value_range (vr
, VR_RANGE
, tem
, tem
, NULL
);
2171 set_value_range_to_varying (vr
);
2175 /* Get value ranges for each operand. For constant operands, create
2176 a new value range with the operand to simplify processing. */
2177 if (TREE_CODE (op0
) == SSA_NAME
)
2178 vr0
= *(get_value_range (op0
));
2179 else if (is_gimple_min_invariant (op0
))
2180 set_value_range_to_value (&vr0
, op0
, NULL
);
2182 set_value_range_to_varying (&vr0
);
2184 if (TREE_CODE (op1
) == SSA_NAME
)
2185 vr1
= *(get_value_range (op1
));
2186 else if (is_gimple_min_invariant (op1
))
2187 set_value_range_to_value (&vr1
, op1
, NULL
);
2189 set_value_range_to_varying (&vr1
);
2191 /* If either range is UNDEFINED, so is the result. */
2192 if (vr0
.type
== VR_UNDEFINED
|| vr1
.type
== VR_UNDEFINED
)
2194 set_value_range_to_undefined (vr
);
2198 /* The type of the resulting value range defaults to VR0.TYPE. */
2201 /* Refuse to operate on VARYING ranges, ranges of different kinds
2202 and symbolic ranges. As an exception, we allow BIT_AND_EXPR
2203 because we may be able to derive a useful range even if one of
2204 the operands is VR_VARYING or symbolic range. Similarly for
2205 divisions. TODO, we may be able to derive anti-ranges in
2207 if (code
!= BIT_AND_EXPR
2208 && code
!= TRUTH_AND_EXPR
2209 && code
!= TRUTH_OR_EXPR
2210 && code
!= TRUNC_DIV_EXPR
2211 && code
!= FLOOR_DIV_EXPR
2212 && code
!= CEIL_DIV_EXPR
2213 && code
!= EXACT_DIV_EXPR
2214 && code
!= ROUND_DIV_EXPR
2215 && code
!= TRUNC_MOD_EXPR
2216 && (vr0
.type
== VR_VARYING
2217 || vr1
.type
== VR_VARYING
2218 || vr0
.type
!= vr1
.type
2219 || symbolic_range_p (&vr0
)
2220 || symbolic_range_p (&vr1
)))
2222 set_value_range_to_varying (vr
);
2226 /* Now evaluate the expression to determine the new range. */
2227 if (POINTER_TYPE_P (expr_type
)
2228 || POINTER_TYPE_P (TREE_TYPE (op0
))
2229 || POINTER_TYPE_P (TREE_TYPE (op1
)))
2231 if (code
== MIN_EXPR
|| code
== MAX_EXPR
)
2233 /* For MIN/MAX expressions with pointers, we only care about
2234 nullness, if both are non null, then the result is nonnull.
2235 If both are null, then the result is null. Otherwise they
2237 if (range_is_nonnull (&vr0
) && range_is_nonnull (&vr1
))
2238 set_value_range_to_nonnull (vr
, expr_type
);
2239 else if (range_is_null (&vr0
) && range_is_null (&vr1
))
2240 set_value_range_to_null (vr
, expr_type
);
2242 set_value_range_to_varying (vr
);
2246 if (code
== POINTER_PLUS_EXPR
)
2248 /* For pointer types, we are really only interested in asserting
2249 whether the expression evaluates to non-NULL. */
2250 if (range_is_nonnull (&vr0
) || range_is_nonnull (&vr1
))
2251 set_value_range_to_nonnull (vr
, expr_type
);
2252 else if (range_is_null (&vr0
) && range_is_null (&vr1
))
2253 set_value_range_to_null (vr
, expr_type
);
2255 set_value_range_to_varying (vr
);
2257 else if (code
== BIT_AND_EXPR
)
2259 /* For pointer types, we are really only interested in asserting
2260 whether the expression evaluates to non-NULL. */
2261 if (range_is_nonnull (&vr0
) && range_is_nonnull (&vr1
))
2262 set_value_range_to_nonnull (vr
, expr_type
);
2263 else if (range_is_null (&vr0
) || range_is_null (&vr1
))
2264 set_value_range_to_null (vr
, expr_type
);
2266 set_value_range_to_varying (vr
);
2274 /* For integer ranges, apply the operation to each end of the
2275 range and see what we end up with. */
2276 if (code
== TRUTH_AND_EXPR
2277 || code
== TRUTH_OR_EXPR
)
2279 /* If one of the operands is zero, we know that the whole
2280 expression evaluates zero. */
2281 if (code
== TRUTH_AND_EXPR
2282 && ((vr0
.type
== VR_RANGE
2283 && integer_zerop (vr0
.min
)
2284 && integer_zerop (vr0
.max
))
2285 || (vr1
.type
== VR_RANGE
2286 && integer_zerop (vr1
.min
)
2287 && integer_zerop (vr1
.max
))))
2290 min
= max
= build_int_cst (expr_type
, 0);
2292 /* If one of the operands is one, we know that the whole
2293 expression evaluates one. */
2294 else if (code
== TRUTH_OR_EXPR
2295 && ((vr0
.type
== VR_RANGE
2296 && integer_onep (vr0
.min
)
2297 && integer_onep (vr0
.max
))
2298 || (vr1
.type
== VR_RANGE
2299 && integer_onep (vr1
.min
)
2300 && integer_onep (vr1
.max
))))
2303 min
= max
= build_int_cst (expr_type
, 1);
2305 else if (vr0
.type
!= VR_VARYING
2306 && vr1
.type
!= VR_VARYING
2307 && vr0
.type
== vr1
.type
2308 && !symbolic_range_p (&vr0
)
2309 && !overflow_infinity_range_p (&vr0
)
2310 && !symbolic_range_p (&vr1
)
2311 && !overflow_infinity_range_p (&vr1
))
2313 /* Boolean expressions cannot be folded with int_const_binop. */
2314 min
= fold_binary (code
, expr_type
, vr0
.min
, vr1
.min
);
2315 max
= fold_binary (code
, expr_type
, vr0
.max
, vr1
.max
);
2319 /* The result of a TRUTH_*_EXPR is always true or false. */
2320 set_value_range_to_truthvalue (vr
, expr_type
);
2324 else if (code
== PLUS_EXPR
2326 || code
== MAX_EXPR
)
2328 /* If we have a PLUS_EXPR with two VR_ANTI_RANGEs, drop to
2329 VR_VARYING. It would take more effort to compute a precise
2330 range for such a case. For example, if we have op0 == 1 and
2331 op1 == -1 with their ranges both being ~[0,0], we would have
2332 op0 + op1 == 0, so we cannot claim that the sum is in ~[0,0].
2333 Note that we are guaranteed to have vr0.type == vr1.type at
2335 if (code
== PLUS_EXPR
&& vr0
.type
== VR_ANTI_RANGE
)
2337 set_value_range_to_varying (vr
);
2341 /* For operations that make the resulting range directly
2342 proportional to the original ranges, apply the operation to
2343 the same end of each range. */
2344 min
= vrp_int_const_binop (code
, vr0
.min
, vr1
.min
);
2345 max
= vrp_int_const_binop (code
, vr0
.max
, vr1
.max
);
2347 /* If both additions overflowed the range kind is still correct.
2348 This happens regularly with subtracting something in unsigned
2350 ??? See PR30318 for all the cases we do not handle. */
2351 if (code
== PLUS_EXPR
2352 && (TREE_OVERFLOW (min
) && !is_overflow_infinity (min
))
2353 && (TREE_OVERFLOW (max
) && !is_overflow_infinity (max
)))
2355 min
= build_int_cst_wide (TREE_TYPE (min
),
2356 TREE_INT_CST_LOW (min
),
2357 TREE_INT_CST_HIGH (min
));
2358 max
= build_int_cst_wide (TREE_TYPE (max
),
2359 TREE_INT_CST_LOW (max
),
2360 TREE_INT_CST_HIGH (max
));
2363 else if (code
== MULT_EXPR
2364 || code
== TRUNC_DIV_EXPR
2365 || code
== FLOOR_DIV_EXPR
2366 || code
== CEIL_DIV_EXPR
2367 || code
== EXACT_DIV_EXPR
2368 || code
== ROUND_DIV_EXPR
2369 || code
== RSHIFT_EXPR
)
2375 /* If we have an unsigned MULT_EXPR with two VR_ANTI_RANGEs,
2376 drop to VR_VARYING. It would take more effort to compute a
2377 precise range for such a case. For example, if we have
2378 op0 == 65536 and op1 == 65536 with their ranges both being
2379 ~[0,0] on a 32-bit machine, we would have op0 * op1 == 0, so
2380 we cannot claim that the product is in ~[0,0]. Note that we
2381 are guaranteed to have vr0.type == vr1.type at this
2383 if (code
== MULT_EXPR
2384 && vr0
.type
== VR_ANTI_RANGE
2385 && !TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (op0
)))
2387 set_value_range_to_varying (vr
);
2391 /* If we have a RSHIFT_EXPR with any shift values outside [0..prec-1],
2392 then drop to VR_VARYING. Outside of this range we get undefined
2393 behavior from the shift operation. We cannot even trust
2394 SHIFT_COUNT_TRUNCATED at this stage, because that applies to rtl
2395 shifts, and the operation at the tree level may be widened. */
2396 if (code
== RSHIFT_EXPR
)
2398 if (vr1
.type
== VR_ANTI_RANGE
2399 || !vrp_expr_computes_nonnegative (op1
, &sop
)
2401 (build_int_cst (TREE_TYPE (vr1
.max
),
2402 TYPE_PRECISION (expr_type
) - 1),
2405 set_value_range_to_varying (vr
);
2410 else if ((code
== TRUNC_DIV_EXPR
2411 || code
== FLOOR_DIV_EXPR
2412 || code
== CEIL_DIV_EXPR
2413 || code
== EXACT_DIV_EXPR
2414 || code
== ROUND_DIV_EXPR
)
2415 && (vr0
.type
!= VR_RANGE
|| symbolic_range_p (&vr0
)))
2417 /* For division, if op1 has VR_RANGE but op0 does not, something
2418 can be deduced just from that range. Say [min, max] / [4, max]
2419 gives [min / 4, max / 4] range. */
2420 if (vr1
.type
== VR_RANGE
2421 && !symbolic_range_p (&vr1
)
2422 && !range_includes_zero_p (&vr1
))
2424 vr0
.type
= type
= VR_RANGE
;
2425 vr0
.min
= vrp_val_min (TREE_TYPE (op0
));
2426 vr0
.max
= vrp_val_max (TREE_TYPE (op1
));
2430 set_value_range_to_varying (vr
);
2435 /* For divisions, if op0 is VR_RANGE, we can deduce a range
2436 even if op1 is VR_VARYING, VR_ANTI_RANGE, symbolic or can
2438 if ((code
== TRUNC_DIV_EXPR
2439 || code
== FLOOR_DIV_EXPR
2440 || code
== CEIL_DIV_EXPR
2441 || code
== EXACT_DIV_EXPR
2442 || code
== ROUND_DIV_EXPR
)
2443 && vr0
.type
== VR_RANGE
2444 && (vr1
.type
!= VR_RANGE
2445 || symbolic_range_p (&vr1
)
2446 || range_includes_zero_p (&vr1
)))
2448 tree zero
= build_int_cst (TREE_TYPE (vr0
.min
), 0);
2454 if (vrp_expr_computes_nonnegative (op1
, &sop
) && !sop
)
2456 /* For unsigned division or when divisor is known
2457 to be non-negative, the range has to cover
2458 all numbers from 0 to max for positive max
2459 and all numbers from min to 0 for negative min. */
2460 cmp
= compare_values (vr0
.max
, zero
);
2463 else if (cmp
== 0 || cmp
== 1)
2467 cmp
= compare_values (vr0
.min
, zero
);
2470 else if (cmp
== 0 || cmp
== -1)
2477 /* Otherwise the range is -max .. max or min .. -min
2478 depending on which bound is bigger in absolute value,
2479 as the division can change the sign. */
2480 abs_extent_range (vr
, vr0
.min
, vr0
.max
);
2483 if (type
== VR_VARYING
)
2485 set_value_range_to_varying (vr
);
2490 /* Multiplications and divisions are a bit tricky to handle,
2491 depending on the mix of signs we have in the two ranges, we
2492 need to operate on different values to get the minimum and
2493 maximum values for the new range. One approach is to figure
2494 out all the variations of range combinations and do the
2497 However, this involves several calls to compare_values and it
2498 is pretty convoluted. It's simpler to do the 4 operations
2499 (MIN0 OP MIN1, MIN0 OP MAX1, MAX0 OP MIN1 and MAX0 OP MAX0 OP
2500 MAX1) and then figure the smallest and largest values to form
2504 gcc_assert ((vr0
.type
== VR_RANGE
2505 || (code
== MULT_EXPR
&& vr0
.type
== VR_ANTI_RANGE
))
2506 && vr0
.type
== vr1
.type
);
2508 /* Compute the 4 cross operations. */
2510 val
[0] = vrp_int_const_binop (code
, vr0
.min
, vr1
.min
);
2511 if (val
[0] == NULL_TREE
)
2514 if (vr1
.max
== vr1
.min
)
2518 val
[1] = vrp_int_const_binop (code
, vr0
.min
, vr1
.max
);
2519 if (val
[1] == NULL_TREE
)
2523 if (vr0
.max
== vr0
.min
)
2527 val
[2] = vrp_int_const_binop (code
, vr0
.max
, vr1
.min
);
2528 if (val
[2] == NULL_TREE
)
2532 if (vr0
.min
== vr0
.max
|| vr1
.min
== vr1
.max
)
2536 val
[3] = vrp_int_const_binop (code
, vr0
.max
, vr1
.max
);
2537 if (val
[3] == NULL_TREE
)
2543 set_value_range_to_varying (vr
);
2547 /* Set MIN to the minimum of VAL[i] and MAX to the maximum
2551 for (i
= 1; i
< 4; i
++)
2553 if (!is_gimple_min_invariant (min
)
2554 || (TREE_OVERFLOW (min
) && !is_overflow_infinity (min
))
2555 || !is_gimple_min_invariant (max
)
2556 || (TREE_OVERFLOW (max
) && !is_overflow_infinity (max
)))
2561 if (!is_gimple_min_invariant (val
[i
])
2562 || (TREE_OVERFLOW (val
[i
])
2563 && !is_overflow_infinity (val
[i
])))
2565 /* If we found an overflowed value, set MIN and MAX
2566 to it so that we set the resulting range to
2572 if (compare_values (val
[i
], min
) == -1)
2575 if (compare_values (val
[i
], max
) == 1)
2581 else if (code
== TRUNC_MOD_EXPR
)
2584 if (vr1
.type
!= VR_RANGE
2585 || symbolic_range_p (&vr1
)
2586 || range_includes_zero_p (&vr1
)
2587 || vrp_val_is_min (vr1
.min
))
2589 set_value_range_to_varying (vr
);
2593 /* Compute MAX <|vr1.min|, |vr1.max|> - 1. */
2594 max
= fold_unary_to_constant (ABS_EXPR
, TREE_TYPE (vr1
.min
), vr1
.min
);
2595 if (tree_int_cst_lt (max
, vr1
.max
))
2597 max
= int_const_binop (MINUS_EXPR
, max
, integer_one_node
, 0);
2598 /* If the dividend is non-negative the modulus will be
2599 non-negative as well. */
2600 if (TYPE_UNSIGNED (TREE_TYPE (max
))
2601 || (vrp_expr_computes_nonnegative (op0
, &sop
) && !sop
))
2602 min
= build_int_cst (TREE_TYPE (max
), 0);
2604 min
= fold_unary_to_constant (NEGATE_EXPR
, TREE_TYPE (max
), max
);
2606 else if (code
== MINUS_EXPR
)
2608 /* If we have a MINUS_EXPR with two VR_ANTI_RANGEs, drop to
2609 VR_VARYING. It would take more effort to compute a precise
2610 range for such a case. For example, if we have op0 == 1 and
2611 op1 == 1 with their ranges both being ~[0,0], we would have
2612 op0 - op1 == 0, so we cannot claim that the difference is in
2613 ~[0,0]. Note that we are guaranteed to have
2614 vr0.type == vr1.type at this point. */
2615 if (vr0
.type
== VR_ANTI_RANGE
)
2617 set_value_range_to_varying (vr
);
2621 /* For MINUS_EXPR, apply the operation to the opposite ends of
2623 min
= vrp_int_const_binop (code
, vr0
.min
, vr1
.max
);
2624 max
= vrp_int_const_binop (code
, vr0
.max
, vr1
.min
);
2626 else if (code
== BIT_AND_EXPR
|| code
== BIT_IOR_EXPR
)
2628 bool vr0_int_cst_singleton_p
, vr1_int_cst_singleton_p
;
2629 bool int_cst_range0
, int_cst_range1
;
2630 double_int may_be_nonzero0
, may_be_nonzero1
;
2631 double_int must_be_nonzero0
, must_be_nonzero1
;
2633 vr0_int_cst_singleton_p
= range_int_cst_singleton_p (&vr0
);
2634 vr1_int_cst_singleton_p
= range_int_cst_singleton_p (&vr1
);
2635 int_cst_range0
= zero_nonzero_bits_from_vr (&vr0
, &may_be_nonzero0
,
2637 int_cst_range1
= zero_nonzero_bits_from_vr (&vr1
, &may_be_nonzero1
,
2641 if (vr0_int_cst_singleton_p
&& vr1_int_cst_singleton_p
)
2642 min
= max
= int_const_binop (code
, vr0
.max
, vr1
.max
, 0);
2643 else if (!int_cst_range0
&& !int_cst_range1
)
2645 set_value_range_to_varying (vr
);
2648 else if (code
== BIT_AND_EXPR
)
2650 min
= double_int_to_tree (expr_type
,
2651 double_int_and (must_be_nonzero0
,
2653 max
= double_int_to_tree (expr_type
,
2654 double_int_and (may_be_nonzero0
,
2656 if (TREE_OVERFLOW (min
) || tree_int_cst_sgn (min
) < 0)
2658 if (TREE_OVERFLOW (max
) || tree_int_cst_sgn (max
) < 0)
2660 if (int_cst_range0
&& tree_int_cst_sgn (vr0
.min
) >= 0)
2662 if (min
== NULL_TREE
)
2663 min
= build_int_cst (expr_type
, 0);
2664 if (max
== NULL_TREE
|| tree_int_cst_lt (vr0
.max
, max
))
2667 if (int_cst_range1
&& tree_int_cst_sgn (vr1
.min
) >= 0)
2669 if (min
== NULL_TREE
)
2670 min
= build_int_cst (expr_type
, 0);
2671 if (max
== NULL_TREE
|| tree_int_cst_lt (vr1
.max
, max
))
2675 else if (!int_cst_range0
2677 || tree_int_cst_sgn (vr0
.min
) < 0
2678 || tree_int_cst_sgn (vr1
.min
) < 0)
2680 set_value_range_to_varying (vr
);
2685 min
= double_int_to_tree (expr_type
,
2686 double_int_ior (must_be_nonzero0
,
2688 max
= double_int_to_tree (expr_type
,
2689 double_int_ior (may_be_nonzero0
,
2691 if (TREE_OVERFLOW (min
) || tree_int_cst_sgn (min
) < 0)
2694 min
= vrp_int_const_binop (MAX_EXPR
, min
, vr0
.min
);
2695 if (TREE_OVERFLOW (max
) || tree_int_cst_sgn (max
) < 0)
2697 min
= vrp_int_const_binop (MAX_EXPR
, min
, vr1
.min
);
2703 /* If either MIN or MAX overflowed, then set the resulting range to
2704 VARYING. But we do accept an overflow infinity
2706 if (min
== NULL_TREE
2707 || !is_gimple_min_invariant (min
)
2708 || (TREE_OVERFLOW (min
) && !is_overflow_infinity (min
))
2710 || !is_gimple_min_invariant (max
)
2711 || (TREE_OVERFLOW (max
) && !is_overflow_infinity (max
)))
2713 set_value_range_to_varying (vr
);
2719 2) [-INF, +-INF(OVF)]
2720 3) [+-INF(OVF), +INF]
2721 4) [+-INF(OVF), +-INF(OVF)]
2722 We learn nothing when we have INF and INF(OVF) on both sides.
2723 Note that we do accept [-INF, -INF] and [+INF, +INF] without
2725 if ((vrp_val_is_min (min
) || is_overflow_infinity (min
))
2726 && (vrp_val_is_max (max
) || is_overflow_infinity (max
)))
2728 set_value_range_to_varying (vr
);
2732 cmp
= compare_values (min
, max
);
2733 if (cmp
== -2 || cmp
== 1)
2735 /* If the new range has its limits swapped around (MIN > MAX),
2736 then the operation caused one of them to wrap around, mark
2737 the new range VARYING. */
2738 set_value_range_to_varying (vr
);
2741 set_value_range (vr
, type
, min
, max
, NULL
);
2745 /* Extract range information from a unary expression EXPR based on
2746 the range of its operand and the expression code. */
2749 extract_range_from_unary_expr (value_range_t
*vr
, enum tree_code code
,
2750 tree type
, tree op0
)
2754 value_range_t vr0
= { VR_UNDEFINED
, NULL_TREE
, NULL_TREE
, NULL
};
2756 /* Refuse to operate on certain unary expressions for which we
2757 cannot easily determine a resulting range. */
2758 if (code
== FIX_TRUNC_EXPR
2759 || code
== FLOAT_EXPR
2760 || code
== BIT_NOT_EXPR
2761 || code
== CONJ_EXPR
)
2763 /* We can still do constant propagation here. */
2764 if ((op0
= op_with_constant_singleton_value_range (op0
)) != NULL_TREE
)
2766 tree tem
= fold_unary (code
, type
, op0
);
2768 && is_gimple_min_invariant (tem
)
2769 && !is_overflow_infinity (tem
))
2771 set_value_range (vr
, VR_RANGE
, tem
, tem
, NULL
);
2775 set_value_range_to_varying (vr
);
2779 /* Get value ranges for the operand. For constant operands, create
2780 a new value range with the operand to simplify processing. */
2781 if (TREE_CODE (op0
) == SSA_NAME
)
2782 vr0
= *(get_value_range (op0
));
2783 else if (is_gimple_min_invariant (op0
))
2784 set_value_range_to_value (&vr0
, op0
, NULL
);
2786 set_value_range_to_varying (&vr0
);
2788 /* If VR0 is UNDEFINED, so is the result. */
2789 if (vr0
.type
== VR_UNDEFINED
)
2791 set_value_range_to_undefined (vr
);
2795 /* Refuse to operate on symbolic ranges, or if neither operand is
2796 a pointer or integral type. */
2797 if ((!INTEGRAL_TYPE_P (TREE_TYPE (op0
))
2798 && !POINTER_TYPE_P (TREE_TYPE (op0
)))
2799 || (vr0
.type
!= VR_VARYING
2800 && symbolic_range_p (&vr0
)))
2802 set_value_range_to_varying (vr
);
2806 /* If the expression involves pointers, we are only interested in
2807 determining if it evaluates to NULL [0, 0] or non-NULL (~[0, 0]). */
2808 if (POINTER_TYPE_P (type
) || POINTER_TYPE_P (TREE_TYPE (op0
)))
2813 if (range_is_nonnull (&vr0
)
2814 || (tree_unary_nonzero_warnv_p (code
, type
, op0
, &sop
)
2816 set_value_range_to_nonnull (vr
, type
);
2817 else if (range_is_null (&vr0
))
2818 set_value_range_to_null (vr
, type
);
2820 set_value_range_to_varying (vr
);
2825 /* Handle unary expressions on integer ranges. */
2826 if (CONVERT_EXPR_CODE_P (code
)
2827 && INTEGRAL_TYPE_P (type
)
2828 && INTEGRAL_TYPE_P (TREE_TYPE (op0
)))
2830 tree inner_type
= TREE_TYPE (op0
);
2831 tree outer_type
= type
;
2833 /* If VR0 is varying and we increase the type precision, assume
2834 a full range for the following transformation. */
2835 if (vr0
.type
== VR_VARYING
2836 && TYPE_PRECISION (inner_type
) < TYPE_PRECISION (outer_type
))
2838 vr0
.type
= VR_RANGE
;
2839 vr0
.min
= TYPE_MIN_VALUE (inner_type
);
2840 vr0
.max
= TYPE_MAX_VALUE (inner_type
);
2843 /* If VR0 is a constant range or anti-range and the conversion is
2844 not truncating we can convert the min and max values and
2845 canonicalize the resulting range. Otherwise we can do the
2846 conversion if the size of the range is less than what the
2847 precision of the target type can represent and the range is
2848 not an anti-range. */
2849 if ((vr0
.type
== VR_RANGE
2850 || vr0
.type
== VR_ANTI_RANGE
)
2851 && TREE_CODE (vr0
.min
) == INTEGER_CST
2852 && TREE_CODE (vr0
.max
) == INTEGER_CST
2853 && (!is_overflow_infinity (vr0
.min
)
2854 || (vr0
.type
== VR_RANGE
2855 && TYPE_PRECISION (outer_type
) > TYPE_PRECISION (inner_type
)
2856 && needs_overflow_infinity (outer_type
)
2857 && supports_overflow_infinity (outer_type
)))
2858 && (!is_overflow_infinity (vr0
.max
)
2859 || (vr0
.type
== VR_RANGE
2860 && TYPE_PRECISION (outer_type
) > TYPE_PRECISION (inner_type
)
2861 && needs_overflow_infinity (outer_type
)
2862 && supports_overflow_infinity (outer_type
)))
2863 && (TYPE_PRECISION (outer_type
) >= TYPE_PRECISION (inner_type
)
2864 || (vr0
.type
== VR_RANGE
2865 && integer_zerop (int_const_binop (RSHIFT_EXPR
,
2866 int_const_binop (MINUS_EXPR
, vr0
.max
, vr0
.min
, 0),
2867 size_int (TYPE_PRECISION (outer_type
)), 0)))))
2869 tree new_min
, new_max
;
2870 new_min
= force_fit_type_double (outer_type
,
2871 tree_to_double_int (vr0
.min
),
2873 new_max
= force_fit_type_double (outer_type
,
2874 tree_to_double_int (vr0
.max
),
2876 if (is_overflow_infinity (vr0
.min
))
2877 new_min
= negative_overflow_infinity (outer_type
);
2878 if (is_overflow_infinity (vr0
.max
))
2879 new_max
= positive_overflow_infinity (outer_type
);
2880 set_and_canonicalize_value_range (vr
, vr0
.type
,
2881 new_min
, new_max
, NULL
);
2885 set_value_range_to_varying (vr
);
2889 /* Conversion of a VR_VARYING value to a wider type can result
2890 in a usable range. So wait until after we've handled conversions
2891 before dropping the result to VR_VARYING if we had a source
2892 operand that is VR_VARYING. */
2893 if (vr0
.type
== VR_VARYING
)
2895 set_value_range_to_varying (vr
);
2899 /* Apply the operation to each end of the range and see what we end
2901 if (code
== NEGATE_EXPR
2902 && !TYPE_UNSIGNED (type
))
2904 /* NEGATE_EXPR flips the range around. We need to treat
2905 TYPE_MIN_VALUE specially. */
2906 if (is_positive_overflow_infinity (vr0
.max
))
2907 min
= negative_overflow_infinity (type
);
2908 else if (is_negative_overflow_infinity (vr0
.max
))
2909 min
= positive_overflow_infinity (type
);
2910 else if (!vrp_val_is_min (vr0
.max
))
2911 min
= fold_unary_to_constant (code
, type
, vr0
.max
);
2912 else if (needs_overflow_infinity (type
))
2914 if (supports_overflow_infinity (type
)
2915 && !is_overflow_infinity (vr0
.min
)
2916 && !vrp_val_is_min (vr0
.min
))
2917 min
= positive_overflow_infinity (type
);
2920 set_value_range_to_varying (vr
);
2925 min
= TYPE_MIN_VALUE (type
);
2927 if (is_positive_overflow_infinity (vr0
.min
))
2928 max
= negative_overflow_infinity (type
);
2929 else if (is_negative_overflow_infinity (vr0
.min
))
2930 max
= positive_overflow_infinity (type
);
2931 else if (!vrp_val_is_min (vr0
.min
))
2932 max
= fold_unary_to_constant (code
, type
, vr0
.min
);
2933 else if (needs_overflow_infinity (type
))
2935 if (supports_overflow_infinity (type
))
2936 max
= positive_overflow_infinity (type
);
2939 set_value_range_to_varying (vr
);
2944 max
= TYPE_MIN_VALUE (type
);
2946 else if (code
== NEGATE_EXPR
2947 && TYPE_UNSIGNED (type
))
2949 if (!range_includes_zero_p (&vr0
))
2951 max
= fold_unary_to_constant (code
, type
, vr0
.min
);
2952 min
= fold_unary_to_constant (code
, type
, vr0
.max
);
2956 if (range_is_null (&vr0
))
2957 set_value_range_to_null (vr
, type
);
2959 set_value_range_to_varying (vr
);
2963 else if (code
== ABS_EXPR
2964 && !TYPE_UNSIGNED (type
))
2966 /* -TYPE_MIN_VALUE = TYPE_MIN_VALUE with flag_wrapv so we can't get a
2968 if (!TYPE_OVERFLOW_UNDEFINED (type
)
2969 && ((vr0
.type
== VR_RANGE
2970 && vrp_val_is_min (vr0
.min
))
2971 || (vr0
.type
== VR_ANTI_RANGE
2972 && !vrp_val_is_min (vr0
.min
)
2973 && !range_includes_zero_p (&vr0
))))
2975 set_value_range_to_varying (vr
);
2979 /* ABS_EXPR may flip the range around, if the original range
2980 included negative values. */
2981 if (is_overflow_infinity (vr0
.min
))
2982 min
= positive_overflow_infinity (type
);
2983 else if (!vrp_val_is_min (vr0
.min
))
2984 min
= fold_unary_to_constant (code
, type
, vr0
.min
);
2985 else if (!needs_overflow_infinity (type
))
2986 min
= TYPE_MAX_VALUE (type
);
2987 else if (supports_overflow_infinity (type
))
2988 min
= positive_overflow_infinity (type
);
2991 set_value_range_to_varying (vr
);
2995 if (is_overflow_infinity (vr0
.max
))
2996 max
= positive_overflow_infinity (type
);
2997 else if (!vrp_val_is_min (vr0
.max
))
2998 max
= fold_unary_to_constant (code
, type
, vr0
.max
);
2999 else if (!needs_overflow_infinity (type
))
3000 max
= TYPE_MAX_VALUE (type
);
3001 else if (supports_overflow_infinity (type
)
3002 /* We shouldn't generate [+INF, +INF] as set_value_range
3003 doesn't like this and ICEs. */
3004 && !is_positive_overflow_infinity (min
))
3005 max
= positive_overflow_infinity (type
);
3008 set_value_range_to_varying (vr
);
3012 cmp
= compare_values (min
, max
);
3014 /* If a VR_ANTI_RANGEs contains zero, then we have
3015 ~[-INF, min(MIN, MAX)]. */
3016 if (vr0
.type
== VR_ANTI_RANGE
)
3018 if (range_includes_zero_p (&vr0
))
3020 /* Take the lower of the two values. */
3024 /* Create ~[-INF, min (abs(MIN), abs(MAX))]
3025 or ~[-INF + 1, min (abs(MIN), abs(MAX))] when
3026 flag_wrapv is set and the original anti-range doesn't include
3027 TYPE_MIN_VALUE, remember -TYPE_MIN_VALUE = TYPE_MIN_VALUE. */
3028 if (TYPE_OVERFLOW_WRAPS (type
))
3030 tree type_min_value
= TYPE_MIN_VALUE (type
);
3032 min
= (vr0
.min
!= type_min_value
3033 ? int_const_binop (PLUS_EXPR
, type_min_value
,
3034 integer_one_node
, 0)
3039 if (overflow_infinity_range_p (&vr0
))
3040 min
= negative_overflow_infinity (type
);
3042 min
= TYPE_MIN_VALUE (type
);
3047 /* All else has failed, so create the range [0, INF], even for
3048 flag_wrapv since TYPE_MIN_VALUE is in the original
3050 vr0
.type
= VR_RANGE
;
3051 min
= build_int_cst (type
, 0);
3052 if (needs_overflow_infinity (type
))
3054 if (supports_overflow_infinity (type
))
3055 max
= positive_overflow_infinity (type
);
3058 set_value_range_to_varying (vr
);
3063 max
= TYPE_MAX_VALUE (type
);
3067 /* If the range contains zero then we know that the minimum value in the
3068 range will be zero. */
3069 else if (range_includes_zero_p (&vr0
))
3073 min
= build_int_cst (type
, 0);
3077 /* If the range was reversed, swap MIN and MAX. */
3088 /* Otherwise, operate on each end of the range. */
3089 min
= fold_unary_to_constant (code
, type
, vr0
.min
);
3090 max
= fold_unary_to_constant (code
, type
, vr0
.max
);
3092 if (needs_overflow_infinity (type
))
3094 gcc_assert (code
!= NEGATE_EXPR
&& code
!= ABS_EXPR
);
3096 /* If both sides have overflowed, we don't know
3098 if ((is_overflow_infinity (vr0
.min
)
3099 || TREE_OVERFLOW (min
))
3100 && (is_overflow_infinity (vr0
.max
)
3101 || TREE_OVERFLOW (max
)))
3103 set_value_range_to_varying (vr
);
3107 if (is_overflow_infinity (vr0
.min
))
3109 else if (TREE_OVERFLOW (min
))
3111 if (supports_overflow_infinity (type
))
3112 min
= (tree_int_cst_sgn (min
) >= 0
3113 ? positive_overflow_infinity (TREE_TYPE (min
))
3114 : negative_overflow_infinity (TREE_TYPE (min
)));
3117 set_value_range_to_varying (vr
);
3122 if (is_overflow_infinity (vr0
.max
))
3124 else if (TREE_OVERFLOW (max
))
3126 if (supports_overflow_infinity (type
))
3127 max
= (tree_int_cst_sgn (max
) >= 0
3128 ? positive_overflow_infinity (TREE_TYPE (max
))
3129 : negative_overflow_infinity (TREE_TYPE (max
)));
3132 set_value_range_to_varying (vr
);
3139 cmp
= compare_values (min
, max
);
3140 if (cmp
== -2 || cmp
== 1)
3142 /* If the new range has its limits swapped around (MIN > MAX),
3143 then the operation caused one of them to wrap around, mark
3144 the new range VARYING. */
3145 set_value_range_to_varying (vr
);
3148 set_value_range (vr
, vr0
.type
, min
, max
, NULL
);
3152 /* Extract range information from a conditional expression EXPR based on
3153 the ranges of each of its operands and the expression code. */
3156 extract_range_from_cond_expr (value_range_t
*vr
, tree expr
)
3159 value_range_t vr0
= { VR_UNDEFINED
, NULL_TREE
, NULL_TREE
, NULL
};
3160 value_range_t vr1
= { VR_UNDEFINED
, NULL_TREE
, NULL_TREE
, NULL
};
3162 /* Get value ranges for each operand. For constant operands, create
3163 a new value range with the operand to simplify processing. */
3164 op0
= COND_EXPR_THEN (expr
);
3165 if (TREE_CODE (op0
) == SSA_NAME
)
3166 vr0
= *(get_value_range (op0
));
3167 else if (is_gimple_min_invariant (op0
))
3168 set_value_range_to_value (&vr0
, op0
, NULL
);
3170 set_value_range_to_varying (&vr0
);
3172 op1
= COND_EXPR_ELSE (expr
);
3173 if (TREE_CODE (op1
) == SSA_NAME
)
3174 vr1
= *(get_value_range (op1
));
3175 else if (is_gimple_min_invariant (op1
))
3176 set_value_range_to_value (&vr1
, op1
, NULL
);
3178 set_value_range_to_varying (&vr1
);
3180 /* The resulting value range is the union of the operand ranges */
3181 vrp_meet (&vr0
, &vr1
);
3182 copy_value_range (vr
, &vr0
);
3186 /* Extract range information from a comparison expression EXPR based
3187 on the range of its operand and the expression code. */
3190 extract_range_from_comparison (value_range_t
*vr
, enum tree_code code
,
3191 tree type
, tree op0
, tree op1
)
3196 val
= vrp_evaluate_conditional_warnv_with_ops (code
, op0
, op1
, false, &sop
,
3199 /* A disadvantage of using a special infinity as an overflow
3200 representation is that we lose the ability to record overflow
3201 when we don't have an infinity. So we have to ignore a result
3202 which relies on overflow. */
3204 if (val
&& !is_overflow_infinity (val
) && !sop
)
3206 /* Since this expression was found on the RHS of an assignment,
3207 its type may be different from _Bool. Convert VAL to EXPR's
3209 val
= fold_convert (type
, val
);
3210 if (is_gimple_min_invariant (val
))
3211 set_value_range_to_value (vr
, val
, vr
->equiv
);
3213 set_value_range (vr
, VR_RANGE
, val
, val
, vr
->equiv
);
3216 /* The result of a comparison is always true or false. */
3217 set_value_range_to_truthvalue (vr
, type
);
3220 /* Try to derive a nonnegative or nonzero range out of STMT relying
3221 primarily on generic routines in fold in conjunction with range data.
3222 Store the result in *VR */
3225 extract_range_basic (value_range_t
*vr
, gimple stmt
)
3228 tree type
= gimple_expr_type (stmt
);
3230 if (INTEGRAL_TYPE_P (type
)
3231 && gimple_stmt_nonnegative_warnv_p (stmt
, &sop
))
3232 set_value_range_to_nonnegative (vr
, type
,
3233 sop
|| stmt_overflow_infinity (stmt
));
3234 else if (vrp_stmt_computes_nonzero (stmt
, &sop
)
3236 set_value_range_to_nonnull (vr
, type
);
3238 set_value_range_to_varying (vr
);
3242 /* Try to compute a useful range out of assignment STMT and store it
3246 extract_range_from_assignment (value_range_t
*vr
, gimple stmt
)
3248 enum tree_code code
= gimple_assign_rhs_code (stmt
);
3250 if (code
== ASSERT_EXPR
)
3251 extract_range_from_assert (vr
, gimple_assign_rhs1 (stmt
));
3252 else if (code
== SSA_NAME
)
3253 extract_range_from_ssa_name (vr
, gimple_assign_rhs1 (stmt
));
3254 else if (TREE_CODE_CLASS (code
) == tcc_binary
3255 || code
== TRUTH_AND_EXPR
3256 || code
== TRUTH_OR_EXPR
3257 || code
== TRUTH_XOR_EXPR
)
3258 extract_range_from_binary_expr (vr
, gimple_assign_rhs_code (stmt
),
3259 gimple_expr_type (stmt
),
3260 gimple_assign_rhs1 (stmt
),
3261 gimple_assign_rhs2 (stmt
));
3262 else if (TREE_CODE_CLASS (code
) == tcc_unary
)
3263 extract_range_from_unary_expr (vr
, gimple_assign_rhs_code (stmt
),
3264 gimple_expr_type (stmt
),
3265 gimple_assign_rhs1 (stmt
));
3266 else if (code
== COND_EXPR
)
3267 extract_range_from_cond_expr (vr
, gimple_assign_rhs1 (stmt
));
3268 else if (TREE_CODE_CLASS (code
) == tcc_comparison
)
3269 extract_range_from_comparison (vr
, gimple_assign_rhs_code (stmt
),
3270 gimple_expr_type (stmt
),
3271 gimple_assign_rhs1 (stmt
),
3272 gimple_assign_rhs2 (stmt
));
3273 else if (get_gimple_rhs_class (code
) == GIMPLE_SINGLE_RHS
3274 && is_gimple_min_invariant (gimple_assign_rhs1 (stmt
)))
3275 set_value_range_to_value (vr
, gimple_assign_rhs1 (stmt
), NULL
);
3277 set_value_range_to_varying (vr
);
3279 if (vr
->type
== VR_VARYING
)
3280 extract_range_basic (vr
, stmt
);
3283 /* Given a range VR, a LOOP and a variable VAR, determine whether it
3284 would be profitable to adjust VR using scalar evolution information
3285 for VAR. If so, update VR with the new limits. */
3288 adjust_range_with_scev (value_range_t
*vr
, struct loop
*loop
,
3289 gimple stmt
, tree var
)
3291 tree init
, step
, chrec
, tmin
, tmax
, min
, max
, type
, tem
;
3292 enum ev_direction dir
;
3294 /* TODO. Don't adjust anti-ranges. An anti-range may provide
3295 better opportunities than a regular range, but I'm not sure. */
3296 if (vr
->type
== VR_ANTI_RANGE
)
3299 chrec
= instantiate_parameters (loop
, analyze_scalar_evolution (loop
, var
));
3301 /* Like in PR19590, scev can return a constant function. */
3302 if (is_gimple_min_invariant (chrec
))
3304 set_value_range_to_value (vr
, chrec
, vr
->equiv
);
3308 if (TREE_CODE (chrec
) != POLYNOMIAL_CHREC
)
3311 init
= initial_condition_in_loop_num (chrec
, loop
->num
);
3312 tem
= op_with_constant_singleton_value_range (init
);
3315 step
= evolution_part_in_loop_num (chrec
, loop
->num
);
3316 tem
= op_with_constant_singleton_value_range (step
);
3320 /* If STEP is symbolic, we can't know whether INIT will be the
3321 minimum or maximum value in the range. Also, unless INIT is
3322 a simple expression, compare_values and possibly other functions
3323 in tree-vrp won't be able to handle it. */
3324 if (step
== NULL_TREE
3325 || !is_gimple_min_invariant (step
)
3326 || !valid_value_p (init
))
3329 dir
= scev_direction (chrec
);
3330 if (/* Do not adjust ranges if we do not know whether the iv increases
3331 or decreases, ... */
3332 dir
== EV_DIR_UNKNOWN
3333 /* ... or if it may wrap. */
3334 || scev_probably_wraps_p (init
, step
, stmt
, get_chrec_loop (chrec
),
3338 /* We use TYPE_MIN_VALUE and TYPE_MAX_VALUE here instead of
3339 negative_overflow_infinity and positive_overflow_infinity,
3340 because we have concluded that the loop probably does not
3343 type
= TREE_TYPE (var
);
3344 if (POINTER_TYPE_P (type
) || !TYPE_MIN_VALUE (type
))
3345 tmin
= lower_bound_in_type (type
, type
);
3347 tmin
= TYPE_MIN_VALUE (type
);
3348 if (POINTER_TYPE_P (type
) || !TYPE_MAX_VALUE (type
))
3349 tmax
= upper_bound_in_type (type
, type
);
3351 tmax
= TYPE_MAX_VALUE (type
);
3353 if (vr
->type
== VR_VARYING
|| vr
->type
== VR_UNDEFINED
)
3358 /* For VARYING or UNDEFINED ranges, just about anything we get
3359 from scalar evolutions should be better. */
3361 if (dir
== EV_DIR_DECREASES
)
3366 /* If we would create an invalid range, then just assume we
3367 know absolutely nothing. This may be over-conservative,
3368 but it's clearly safe, and should happen only in unreachable
3369 parts of code, or for invalid programs. */
3370 if (compare_values (min
, max
) == 1)
3373 set_value_range (vr
, VR_RANGE
, min
, max
, vr
->equiv
);
3375 else if (vr
->type
== VR_RANGE
)
3380 if (dir
== EV_DIR_DECREASES
)
3382 /* INIT is the maximum value. If INIT is lower than VR->MAX
3383 but no smaller than VR->MIN, set VR->MAX to INIT. */
3384 if (compare_values (init
, max
) == -1)
3388 /* If we just created an invalid range with the minimum
3389 greater than the maximum, we fail conservatively.
3390 This should happen only in unreachable
3391 parts of code, or for invalid programs. */
3392 if (compare_values (min
, max
) == 1)
3396 /* According to the loop information, the variable does not
3397 overflow. If we think it does, probably because of an
3398 overflow due to arithmetic on a different INF value,
3400 if (is_negative_overflow_infinity (min
))
3405 /* If INIT is bigger than VR->MIN, set VR->MIN to INIT. */
3406 if (compare_values (init
, min
) == 1)
3410 /* Again, avoid creating invalid range by failing. */
3411 if (compare_values (min
, max
) == 1)
3415 if (is_positive_overflow_infinity (max
))
3419 set_value_range (vr
, VR_RANGE
, min
, max
, vr
->equiv
);
3423 /* Return true if VAR may overflow at STMT. This checks any available
3424 loop information to see if we can determine that VAR does not
3428 vrp_var_may_overflow (tree var
, gimple stmt
)
3431 tree chrec
, init
, step
;
3433 if (current_loops
== NULL
)
3436 l
= loop_containing_stmt (stmt
);
3441 chrec
= instantiate_parameters (l
, analyze_scalar_evolution (l
, var
));
3442 if (TREE_CODE (chrec
) != POLYNOMIAL_CHREC
)
3445 init
= initial_condition_in_loop_num (chrec
, l
->num
);
3446 step
= evolution_part_in_loop_num (chrec
, l
->num
);
3448 if (step
== NULL_TREE
3449 || !is_gimple_min_invariant (step
)
3450 || !valid_value_p (init
))
3453 /* If we get here, we know something useful about VAR based on the
3454 loop information. If it wraps, it may overflow. */
3456 if (scev_probably_wraps_p (init
, step
, stmt
, get_chrec_loop (chrec
),
3460 if (dump_file
&& (dump_flags
& TDF_DETAILS
) != 0)
3462 print_generic_expr (dump_file
, var
, 0);
3463 fprintf (dump_file
, ": loop information indicates does not overflow\n");
3470 /* Given two numeric value ranges VR0, VR1 and a comparison code COMP:
3472 - Return BOOLEAN_TRUE_NODE if VR0 COMP VR1 always returns true for
3473 all the values in the ranges.
3475 - Return BOOLEAN_FALSE_NODE if the comparison always returns false.
3477 - Return NULL_TREE if it is not always possible to determine the
3478 value of the comparison.
3480 Also set *STRICT_OVERFLOW_P to indicate whether a range with an
3481 overflow infinity was used in the test. */
3485 compare_ranges (enum tree_code comp
, value_range_t
*vr0
, value_range_t
*vr1
,
3486 bool *strict_overflow_p
)
3488 /* VARYING or UNDEFINED ranges cannot be compared. */
3489 if (vr0
->type
== VR_VARYING
3490 || vr0
->type
== VR_UNDEFINED
3491 || vr1
->type
== VR_VARYING
3492 || vr1
->type
== VR_UNDEFINED
)
3495 /* Anti-ranges need to be handled separately. */
3496 if (vr0
->type
== VR_ANTI_RANGE
|| vr1
->type
== VR_ANTI_RANGE
)
3498 /* If both are anti-ranges, then we cannot compute any
3500 if (vr0
->type
== VR_ANTI_RANGE
&& vr1
->type
== VR_ANTI_RANGE
)
3503 /* These comparisons are never statically computable. */
3510 /* Equality can be computed only between a range and an
3511 anti-range. ~[VAL1, VAL2] == [VAL1, VAL2] is always false. */
3512 if (vr0
->type
== VR_RANGE
)
3514 /* To simplify processing, make VR0 the anti-range. */
3515 value_range_t
*tmp
= vr0
;
3520 gcc_assert (comp
== NE_EXPR
|| comp
== EQ_EXPR
);
3522 if (compare_values_warnv (vr0
->min
, vr1
->min
, strict_overflow_p
) == 0
3523 && compare_values_warnv (vr0
->max
, vr1
->max
, strict_overflow_p
) == 0)
3524 return (comp
== NE_EXPR
) ? boolean_true_node
: boolean_false_node
;
3529 if (!usable_range_p (vr0
, strict_overflow_p
)
3530 || !usable_range_p (vr1
, strict_overflow_p
))
3533 /* Simplify processing. If COMP is GT_EXPR or GE_EXPR, switch the
3534 operands around and change the comparison code. */
3535 if (comp
== GT_EXPR
|| comp
== GE_EXPR
)
3538 comp
= (comp
== GT_EXPR
) ? LT_EXPR
: LE_EXPR
;
3544 if (comp
== EQ_EXPR
)
3546 /* Equality may only be computed if both ranges represent
3547 exactly one value. */
3548 if (compare_values_warnv (vr0
->min
, vr0
->max
, strict_overflow_p
) == 0
3549 && compare_values_warnv (vr1
->min
, vr1
->max
, strict_overflow_p
) == 0)
3551 int cmp_min
= compare_values_warnv (vr0
->min
, vr1
->min
,
3553 int cmp_max
= compare_values_warnv (vr0
->max
, vr1
->max
,
3555 if (cmp_min
== 0 && cmp_max
== 0)
3556 return boolean_true_node
;
3557 else if (cmp_min
!= -2 && cmp_max
!= -2)
3558 return boolean_false_node
;
3560 /* If [V0_MIN, V1_MAX] < [V1_MIN, V1_MAX] then V0 != V1. */
3561 else if (compare_values_warnv (vr0
->min
, vr1
->max
,
3562 strict_overflow_p
) == 1
3563 || compare_values_warnv (vr1
->min
, vr0
->max
,
3564 strict_overflow_p
) == 1)
3565 return boolean_false_node
;
3569 else if (comp
== NE_EXPR
)
3573 /* If VR0 is completely to the left or completely to the right
3574 of VR1, they are always different. Notice that we need to
3575 make sure that both comparisons yield similar results to
3576 avoid comparing values that cannot be compared at
3578 cmp1
= compare_values_warnv (vr0
->max
, vr1
->min
, strict_overflow_p
);
3579 cmp2
= compare_values_warnv (vr0
->min
, vr1
->max
, strict_overflow_p
);
3580 if ((cmp1
== -1 && cmp2
== -1) || (cmp1
== 1 && cmp2
== 1))
3581 return boolean_true_node
;
3583 /* If VR0 and VR1 represent a single value and are identical,
3585 else if (compare_values_warnv (vr0
->min
, vr0
->max
,
3586 strict_overflow_p
) == 0
3587 && compare_values_warnv (vr1
->min
, vr1
->max
,
3588 strict_overflow_p
) == 0
3589 && compare_values_warnv (vr0
->min
, vr1
->min
,
3590 strict_overflow_p
) == 0
3591 && compare_values_warnv (vr0
->max
, vr1
->max
,
3592 strict_overflow_p
) == 0)
3593 return boolean_false_node
;
3595 /* Otherwise, they may or may not be different. */
3599 else if (comp
== LT_EXPR
|| comp
== LE_EXPR
)
3603 /* If VR0 is to the left of VR1, return true. */
3604 tst
= compare_values_warnv (vr0
->max
, vr1
->min
, strict_overflow_p
);
3605 if ((comp
== LT_EXPR
&& tst
== -1)
3606 || (comp
== LE_EXPR
&& (tst
== -1 || tst
== 0)))
3608 if (overflow_infinity_range_p (vr0
)
3609 || overflow_infinity_range_p (vr1
))
3610 *strict_overflow_p
= true;
3611 return boolean_true_node
;
3614 /* If VR0 is to the right of VR1, return false. */
3615 tst
= compare_values_warnv (vr0
->min
, vr1
->max
, strict_overflow_p
);
3616 if ((comp
== LT_EXPR
&& (tst
== 0 || tst
== 1))
3617 || (comp
== LE_EXPR
&& tst
== 1))
3619 if (overflow_infinity_range_p (vr0
)
3620 || overflow_infinity_range_p (vr1
))
3621 *strict_overflow_p
= true;
3622 return boolean_false_node
;
3625 /* Otherwise, we don't know. */
3633 /* Given a value range VR, a value VAL and a comparison code COMP, return
3634 BOOLEAN_TRUE_NODE if VR COMP VAL always returns true for all the
3635 values in VR. Return BOOLEAN_FALSE_NODE if the comparison
3636 always returns false. Return NULL_TREE if it is not always
3637 possible to determine the value of the comparison. Also set
3638 *STRICT_OVERFLOW_P to indicate whether a range with an overflow
3639 infinity was used in the test. */
3642 compare_range_with_value (enum tree_code comp
, value_range_t
*vr
, tree val
,
3643 bool *strict_overflow_p
)
3645 if (vr
->type
== VR_VARYING
|| vr
->type
== VR_UNDEFINED
)
3648 /* Anti-ranges need to be handled separately. */
3649 if (vr
->type
== VR_ANTI_RANGE
)
3651 /* For anti-ranges, the only predicates that we can compute at
3652 compile time are equality and inequality. */
3659 /* ~[VAL_1, VAL_2] OP VAL is known if VAL_1 <= VAL <= VAL_2. */
3660 if (value_inside_range (val
, vr
) == 1)
3661 return (comp
== NE_EXPR
) ? boolean_true_node
: boolean_false_node
;
3666 if (!usable_range_p (vr
, strict_overflow_p
))
3669 if (comp
== EQ_EXPR
)
3671 /* EQ_EXPR may only be computed if VR represents exactly
3673 if (compare_values_warnv (vr
->min
, vr
->max
, strict_overflow_p
) == 0)
3675 int cmp
= compare_values_warnv (vr
->min
, val
, strict_overflow_p
);
3677 return boolean_true_node
;
3678 else if (cmp
== -1 || cmp
== 1 || cmp
== 2)
3679 return boolean_false_node
;
3681 else if (compare_values_warnv (val
, vr
->min
, strict_overflow_p
) == -1
3682 || compare_values_warnv (vr
->max
, val
, strict_overflow_p
) == -1)
3683 return boolean_false_node
;
3687 else if (comp
== NE_EXPR
)
3689 /* If VAL is not inside VR, then they are always different. */
3690 if (compare_values_warnv (vr
->max
, val
, strict_overflow_p
) == -1
3691 || compare_values_warnv (vr
->min
, val
, strict_overflow_p
) == 1)
3692 return boolean_true_node
;
3694 /* If VR represents exactly one value equal to VAL, then return
3696 if (compare_values_warnv (vr
->min
, vr
->max
, strict_overflow_p
) == 0
3697 && compare_values_warnv (vr
->min
, val
, strict_overflow_p
) == 0)
3698 return boolean_false_node
;
3700 /* Otherwise, they may or may not be different. */
3703 else if (comp
== LT_EXPR
|| comp
== LE_EXPR
)
3707 /* If VR is to the left of VAL, return true. */
3708 tst
= compare_values_warnv (vr
->max
, val
, strict_overflow_p
);
3709 if ((comp
== LT_EXPR
&& tst
== -1)
3710 || (comp
== LE_EXPR
&& (tst
== -1 || tst
== 0)))
3712 if (overflow_infinity_range_p (vr
))
3713 *strict_overflow_p
= true;
3714 return boolean_true_node
;
3717 /* If VR is to the right of VAL, return false. */
3718 tst
= compare_values_warnv (vr
->min
, val
, strict_overflow_p
);
3719 if ((comp
== LT_EXPR
&& (tst
== 0 || tst
== 1))
3720 || (comp
== LE_EXPR
&& tst
== 1))
3722 if (overflow_infinity_range_p (vr
))
3723 *strict_overflow_p
= true;
3724 return boolean_false_node
;
3727 /* Otherwise, we don't know. */
3730 else if (comp
== GT_EXPR
|| comp
== GE_EXPR
)
3734 /* If VR is to the right of VAL, return true. */
3735 tst
= compare_values_warnv (vr
->min
, val
, strict_overflow_p
);
3736 if ((comp
== GT_EXPR
&& tst
== 1)
3737 || (comp
== GE_EXPR
&& (tst
== 0 || tst
== 1)))
3739 if (overflow_infinity_range_p (vr
))
3740 *strict_overflow_p
= true;
3741 return boolean_true_node
;
3744 /* If VR is to the left of VAL, return false. */
3745 tst
= compare_values_warnv (vr
->max
, val
, strict_overflow_p
);
3746 if ((comp
== GT_EXPR
&& (tst
== -1 || tst
== 0))
3747 || (comp
== GE_EXPR
&& tst
== -1))
3749 if (overflow_infinity_range_p (vr
))
3750 *strict_overflow_p
= true;
3751 return boolean_false_node
;
3754 /* Otherwise, we don't know. */
3762 /* Debugging dumps. */
3764 void dump_value_range (FILE *, value_range_t
*);
3765 void debug_value_range (value_range_t
*);
3766 void dump_all_value_ranges (FILE *);
3767 void debug_all_value_ranges (void);
3768 void dump_vr_equiv (FILE *, bitmap
);
3769 void debug_vr_equiv (bitmap
);
3772 /* Dump value range VR to FILE. */
3775 dump_value_range (FILE *file
, value_range_t
*vr
)
3778 fprintf (file
, "[]");
3779 else if (vr
->type
== VR_UNDEFINED
)
3780 fprintf (file
, "UNDEFINED");
3781 else if (vr
->type
== VR_RANGE
|| vr
->type
== VR_ANTI_RANGE
)
3783 tree type
= TREE_TYPE (vr
->min
);
3785 fprintf (file
, "%s[", (vr
->type
== VR_ANTI_RANGE
) ? "~" : "");
3787 if (is_negative_overflow_infinity (vr
->min
))
3788 fprintf (file
, "-INF(OVF)");
3789 else if (INTEGRAL_TYPE_P (type
)
3790 && !TYPE_UNSIGNED (type
)
3791 && vrp_val_is_min (vr
->min
))
3792 fprintf (file
, "-INF");
3794 print_generic_expr (file
, vr
->min
, 0);
3796 fprintf (file
, ", ");
3798 if (is_positive_overflow_infinity (vr
->max
))
3799 fprintf (file
, "+INF(OVF)");
3800 else if (INTEGRAL_TYPE_P (type
)
3801 && vrp_val_is_max (vr
->max
))
3802 fprintf (file
, "+INF");
3804 print_generic_expr (file
, vr
->max
, 0);
3806 fprintf (file
, "]");
3813 fprintf (file
, " EQUIVALENCES: { ");
3815 EXECUTE_IF_SET_IN_BITMAP (vr
->equiv
, 0, i
, bi
)
3817 print_generic_expr (file
, ssa_name (i
), 0);
3818 fprintf (file
, " ");
3822 fprintf (file
, "} (%u elements)", c
);
3825 else if (vr
->type
== VR_VARYING
)
3826 fprintf (file
, "VARYING");
3828 fprintf (file
, "INVALID RANGE");
3832 /* Dump value range VR to stderr. */
3835 debug_value_range (value_range_t
*vr
)
3837 dump_value_range (stderr
, vr
);
3838 fprintf (stderr
, "\n");
3842 /* Dump value ranges of all SSA_NAMEs to FILE. */
3845 dump_all_value_ranges (FILE *file
)
3849 for (i
= 0; i
< num_ssa_names
; i
++)
3853 print_generic_expr (file
, ssa_name (i
), 0);
3854 fprintf (file
, ": ");
3855 dump_value_range (file
, vr_value
[i
]);
3856 fprintf (file
, "\n");
3860 fprintf (file
, "\n");
3864 /* Dump all value ranges to stderr. */
3867 debug_all_value_ranges (void)
3869 dump_all_value_ranges (stderr
);
3873 /* Given a COND_EXPR COND of the form 'V OP W', and an SSA name V,
3874 create a new SSA name N and return the assertion assignment
3875 'V = ASSERT_EXPR <V, V OP W>'. */
3878 build_assert_expr_for (tree cond
, tree v
)
3883 gcc_assert (TREE_CODE (v
) == SSA_NAME
);
3884 n
= duplicate_ssa_name (v
, NULL
);
3886 if (COMPARISON_CLASS_P (cond
))
3888 tree a
= build2 (ASSERT_EXPR
, TREE_TYPE (v
), v
, cond
);
3889 assertion
= gimple_build_assign (n
, a
);
3891 else if (TREE_CODE (cond
) == TRUTH_NOT_EXPR
)
3893 /* Given !V, build the assignment N = false. */
3894 tree op0
= TREE_OPERAND (cond
, 0);
3895 gcc_assert (op0
== v
);
3896 assertion
= gimple_build_assign (n
, boolean_false_node
);
3898 else if (TREE_CODE (cond
) == SSA_NAME
)
3900 /* Given V, build the assignment N = true. */
3901 gcc_assert (v
== cond
);
3902 assertion
= gimple_build_assign (n
, boolean_true_node
);
3907 SSA_NAME_DEF_STMT (n
) = assertion
;
3909 /* The new ASSERT_EXPR, creates a new SSA name that replaces the
3910 operand of the ASSERT_EXPR. Register the new name and the old one
3911 in the replacement table so that we can fix the SSA web after
3912 adding all the ASSERT_EXPRs. */
3913 register_new_name_mapping (n
, v
);
3919 /* Return false if EXPR is a predicate expression involving floating
3923 fp_predicate (gimple stmt
)
3925 GIMPLE_CHECK (stmt
, GIMPLE_COND
);
3927 return FLOAT_TYPE_P (TREE_TYPE (gimple_cond_lhs (stmt
)));
3931 /* If the range of values taken by OP can be inferred after STMT executes,
3932 return the comparison code (COMP_CODE_P) and value (VAL_P) that
3933 describes the inferred range. Return true if a range could be
3937 infer_value_range (gimple stmt
, tree op
, enum tree_code
*comp_code_p
, tree
*val_p
)
3940 *comp_code_p
= ERROR_MARK
;
3942 /* Do not attempt to infer anything in names that flow through
3944 if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (op
))
3947 /* Similarly, don't infer anything from statements that may throw
3949 if (stmt_could_throw_p (stmt
))
3952 /* If STMT is the last statement of a basic block with no
3953 successors, there is no point inferring anything about any of its
3954 operands. We would not be able to find a proper insertion point
3955 for the assertion, anyway. */
3956 if (stmt_ends_bb_p (stmt
) && EDGE_COUNT (gimple_bb (stmt
)->succs
) == 0)
3959 /* We can only assume that a pointer dereference will yield
3960 non-NULL if -fdelete-null-pointer-checks is enabled. */
3961 if (flag_delete_null_pointer_checks
3962 && POINTER_TYPE_P (TREE_TYPE (op
))
3963 && gimple_code (stmt
) != GIMPLE_ASM
)
3965 unsigned num_uses
, num_loads
, num_stores
;
3967 count_uses_and_derefs (op
, stmt
, &num_uses
, &num_loads
, &num_stores
);
3968 if (num_loads
+ num_stores
> 0)
3970 *val_p
= build_int_cst (TREE_TYPE (op
), 0);
3971 *comp_code_p
= NE_EXPR
;
3980 void dump_asserts_for (FILE *, tree
);
3981 void debug_asserts_for (tree
);
3982 void dump_all_asserts (FILE *);
3983 void debug_all_asserts (void);
3985 /* Dump all the registered assertions for NAME to FILE. */
3988 dump_asserts_for (FILE *file
, tree name
)
3992 fprintf (file
, "Assertions to be inserted for ");
3993 print_generic_expr (file
, name
, 0);
3994 fprintf (file
, "\n");
3996 loc
= asserts_for
[SSA_NAME_VERSION (name
)];
3999 fprintf (file
, "\t");
4000 print_gimple_stmt (file
, gsi_stmt (loc
->si
), 0, 0);
4001 fprintf (file
, "\n\tBB #%d", loc
->bb
->index
);
4004 fprintf (file
, "\n\tEDGE %d->%d", loc
->e
->src
->index
,
4005 loc
->e
->dest
->index
);
4006 dump_edge_info (file
, loc
->e
, 0);
4008 fprintf (file
, "\n\tPREDICATE: ");
4009 print_generic_expr (file
, name
, 0);
4010 fprintf (file
, " %s ", tree_code_name
[(int)loc
->comp_code
]);
4011 print_generic_expr (file
, loc
->val
, 0);
4012 fprintf (file
, "\n\n");
4016 fprintf (file
, "\n");
4020 /* Dump all the registered assertions for NAME to stderr. */
4023 debug_asserts_for (tree name
)
4025 dump_asserts_for (stderr
, name
);
4029 /* Dump all the registered assertions for all the names to FILE. */
4032 dump_all_asserts (FILE *file
)
4037 fprintf (file
, "\nASSERT_EXPRs to be inserted\n\n");
4038 EXECUTE_IF_SET_IN_BITMAP (need_assert_for
, 0, i
, bi
)
4039 dump_asserts_for (file
, ssa_name (i
));
4040 fprintf (file
, "\n");
4044 /* Dump all the registered assertions for all the names to stderr. */
4047 debug_all_asserts (void)
4049 dump_all_asserts (stderr
);
4053 /* If NAME doesn't have an ASSERT_EXPR registered for asserting
4054 'EXPR COMP_CODE VAL' at a location that dominates block BB or
4055 E->DEST, then register this location as a possible insertion point
4056 for ASSERT_EXPR <NAME, EXPR COMP_CODE VAL>.
4058 BB, E and SI provide the exact insertion point for the new
4059 ASSERT_EXPR. If BB is NULL, then the ASSERT_EXPR is to be inserted
4060 on edge E. Otherwise, if E is NULL, the ASSERT_EXPR is inserted on
4061 BB. If SI points to a COND_EXPR or a SWITCH_EXPR statement, then E
4062 must not be NULL. */
4065 register_new_assert_for (tree name
, tree expr
,
4066 enum tree_code comp_code
,
4070 gimple_stmt_iterator si
)
4072 assert_locus_t n
, loc
, last_loc
;
4073 basic_block dest_bb
;
4075 #if defined ENABLE_CHECKING
4076 gcc_assert (bb
== NULL
|| e
== NULL
);
4079 gcc_assert (gimple_code (gsi_stmt (si
)) != GIMPLE_COND
4080 && gimple_code (gsi_stmt (si
)) != GIMPLE_SWITCH
);
4083 /* Never build an assert comparing against an integer constant with
4084 TREE_OVERFLOW set. This confuses our undefined overflow warning
4086 if (TREE_CODE (val
) == INTEGER_CST
4087 && TREE_OVERFLOW (val
))
4088 val
= build_int_cst_wide (TREE_TYPE (val
),
4089 TREE_INT_CST_LOW (val
), TREE_INT_CST_HIGH (val
));
4091 /* The new assertion A will be inserted at BB or E. We need to
4092 determine if the new location is dominated by a previously
4093 registered location for A. If we are doing an edge insertion,
4094 assume that A will be inserted at E->DEST. Note that this is not
4097 If E is a critical edge, it will be split. But even if E is
4098 split, the new block will dominate the same set of blocks that
4101 The reverse, however, is not true, blocks dominated by E->DEST
4102 will not be dominated by the new block created to split E. So,
4103 if the insertion location is on a critical edge, we will not use
4104 the new location to move another assertion previously registered
4105 at a block dominated by E->DEST. */
4106 dest_bb
= (bb
) ? bb
: e
->dest
;
4108 /* If NAME already has an ASSERT_EXPR registered for COMP_CODE and
4109 VAL at a block dominating DEST_BB, then we don't need to insert a new
4110 one. Similarly, if the same assertion already exists at a block
4111 dominated by DEST_BB and the new location is not on a critical
4112 edge, then update the existing location for the assertion (i.e.,
4113 move the assertion up in the dominance tree).
4115 Note, this is implemented as a simple linked list because there
4116 should not be more than a handful of assertions registered per
4117 name. If this becomes a performance problem, a table hashed by
4118 COMP_CODE and VAL could be implemented. */
4119 loc
= asserts_for
[SSA_NAME_VERSION (name
)];
4123 if (loc
->comp_code
== comp_code
4125 || operand_equal_p (loc
->val
, val
, 0))
4126 && (loc
->expr
== expr
4127 || operand_equal_p (loc
->expr
, expr
, 0)))
4129 /* If the assertion NAME COMP_CODE VAL has already been
4130 registered at a basic block that dominates DEST_BB, then
4131 we don't need to insert the same assertion again. Note
4132 that we don't check strict dominance here to avoid
4133 replicating the same assertion inside the same basic
4134 block more than once (e.g., when a pointer is
4135 dereferenced several times inside a block).
4137 An exception to this rule are edge insertions. If the
4138 new assertion is to be inserted on edge E, then it will
4139 dominate all the other insertions that we may want to
4140 insert in DEST_BB. So, if we are doing an edge
4141 insertion, don't do this dominance check. */
4143 && dominated_by_p (CDI_DOMINATORS
, dest_bb
, loc
->bb
))
4146 /* Otherwise, if E is not a critical edge and DEST_BB
4147 dominates the existing location for the assertion, move
4148 the assertion up in the dominance tree by updating its
4149 location information. */
4150 if ((e
== NULL
|| !EDGE_CRITICAL_P (e
))
4151 && dominated_by_p (CDI_DOMINATORS
, loc
->bb
, dest_bb
))
4160 /* Update the last node of the list and move to the next one. */
4165 /* If we didn't find an assertion already registered for
4166 NAME COMP_CODE VAL, add a new one at the end of the list of
4167 assertions associated with NAME. */
4168 n
= XNEW (struct assert_locus_d
);
4172 n
->comp_code
= comp_code
;
4180 asserts_for
[SSA_NAME_VERSION (name
)] = n
;
4182 bitmap_set_bit (need_assert_for
, SSA_NAME_VERSION (name
));
4185 /* (COND_OP0 COND_CODE COND_OP1) is a predicate which uses NAME.
4186 Extract a suitable test code and value and store them into *CODE_P and
4187 *VAL_P so the predicate is normalized to NAME *CODE_P *VAL_P.
4189 If no extraction was possible, return FALSE, otherwise return TRUE.
4191 If INVERT is true, then we invert the result stored into *CODE_P. */
4194 extract_code_and_val_from_cond_with_ops (tree name
, enum tree_code cond_code
,
4195 tree cond_op0
, tree cond_op1
,
4196 bool invert
, enum tree_code
*code_p
,
4199 enum tree_code comp_code
;
4202 /* Otherwise, we have a comparison of the form NAME COMP VAL
4203 or VAL COMP NAME. */
4204 if (name
== cond_op1
)
4206 /* If the predicate is of the form VAL COMP NAME, flip
4207 COMP around because we need to register NAME as the
4208 first operand in the predicate. */
4209 comp_code
= swap_tree_comparison (cond_code
);
4214 /* The comparison is of the form NAME COMP VAL, so the
4215 comparison code remains unchanged. */
4216 comp_code
= cond_code
;
4220 /* Invert the comparison code as necessary. */
4222 comp_code
= invert_tree_comparison (comp_code
, 0);
4224 /* VRP does not handle float types. */
4225 if (SCALAR_FLOAT_TYPE_P (TREE_TYPE (val
)))
4228 /* Do not register always-false predicates.
4229 FIXME: this works around a limitation in fold() when dealing with
4230 enumerations. Given 'enum { N1, N2 } x;', fold will not
4231 fold 'if (x > N2)' to 'if (0)'. */
4232 if ((comp_code
== GT_EXPR
|| comp_code
== LT_EXPR
)
4233 && INTEGRAL_TYPE_P (TREE_TYPE (val
)))
4235 tree min
= TYPE_MIN_VALUE (TREE_TYPE (val
));
4236 tree max
= TYPE_MAX_VALUE (TREE_TYPE (val
));
4238 if (comp_code
== GT_EXPR
4240 || compare_values (val
, max
) == 0))
4243 if (comp_code
== LT_EXPR
4245 || compare_values (val
, min
) == 0))
4248 *code_p
= comp_code
;
4253 /* Try to register an edge assertion for SSA name NAME on edge E for
4254 the condition COND contributing to the conditional jump pointed to by BSI.
4255 Invert the condition COND if INVERT is true.
4256 Return true if an assertion for NAME could be registered. */
4259 register_edge_assert_for_2 (tree name
, edge e
, gimple_stmt_iterator bsi
,
4260 enum tree_code cond_code
,
4261 tree cond_op0
, tree cond_op1
, bool invert
)
4264 enum tree_code comp_code
;
4265 bool retval
= false;
4267 if (!extract_code_and_val_from_cond_with_ops (name
, cond_code
,
4270 invert
, &comp_code
, &val
))
4273 /* Only register an ASSERT_EXPR if NAME was found in the sub-graph
4274 reachable from E. */
4275 if (live_on_edge (e
, name
)
4276 && !has_single_use (name
))
4278 register_new_assert_for (name
, name
, comp_code
, val
, NULL
, e
, bsi
);
4282 /* In the case of NAME <= CST and NAME being defined as
4283 NAME = (unsigned) NAME2 + CST2 we can assert NAME2 >= -CST2
4284 and NAME2 <= CST - CST2. We can do the same for NAME > CST.
4285 This catches range and anti-range tests. */
4286 if ((comp_code
== LE_EXPR
4287 || comp_code
== GT_EXPR
)
4288 && TREE_CODE (val
) == INTEGER_CST
4289 && TYPE_UNSIGNED (TREE_TYPE (val
)))
4291 gimple def_stmt
= SSA_NAME_DEF_STMT (name
);
4292 tree cst2
= NULL_TREE
, name2
= NULL_TREE
, name3
= NULL_TREE
;
4294 /* Extract CST2 from the (optional) addition. */
4295 if (is_gimple_assign (def_stmt
)
4296 && gimple_assign_rhs_code (def_stmt
) == PLUS_EXPR
)
4298 name2
= gimple_assign_rhs1 (def_stmt
);
4299 cst2
= gimple_assign_rhs2 (def_stmt
);
4300 if (TREE_CODE (name2
) == SSA_NAME
4301 && TREE_CODE (cst2
) == INTEGER_CST
)
4302 def_stmt
= SSA_NAME_DEF_STMT (name2
);
4305 /* Extract NAME2 from the (optional) sign-changing cast. */
4306 if (gimple_assign_cast_p (def_stmt
))
4308 if (CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (def_stmt
))
4309 && ! TYPE_UNSIGNED (TREE_TYPE (gimple_assign_rhs1 (def_stmt
)))
4310 && (TYPE_PRECISION (gimple_expr_type (def_stmt
))
4311 == TYPE_PRECISION (TREE_TYPE (gimple_assign_rhs1 (def_stmt
)))))
4312 name3
= gimple_assign_rhs1 (def_stmt
);
4315 /* If name3 is used later, create an ASSERT_EXPR for it. */
4316 if (name3
!= NULL_TREE
4317 && TREE_CODE (name3
) == SSA_NAME
4318 && (cst2
== NULL_TREE
4319 || TREE_CODE (cst2
) == INTEGER_CST
)
4320 && INTEGRAL_TYPE_P (TREE_TYPE (name3
))
4321 && live_on_edge (e
, name3
)
4322 && !has_single_use (name3
))
4326 /* Build an expression for the range test. */
4327 tmp
= build1 (NOP_EXPR
, TREE_TYPE (name
), name3
);
4328 if (cst2
!= NULL_TREE
)
4329 tmp
= build2 (PLUS_EXPR
, TREE_TYPE (name
), tmp
, cst2
);
4333 fprintf (dump_file
, "Adding assert for ");
4334 print_generic_expr (dump_file
, name3
, 0);
4335 fprintf (dump_file
, " from ");
4336 print_generic_expr (dump_file
, tmp
, 0);
4337 fprintf (dump_file
, "\n");
4340 register_new_assert_for (name3
, tmp
, comp_code
, val
, NULL
, e
, bsi
);
4345 /* If name2 is used later, create an ASSERT_EXPR for it. */
4346 if (name2
!= NULL_TREE
4347 && TREE_CODE (name2
) == SSA_NAME
4348 && TREE_CODE (cst2
) == INTEGER_CST
4349 && INTEGRAL_TYPE_P (TREE_TYPE (name2
))
4350 && live_on_edge (e
, name2
)
4351 && !has_single_use (name2
))
4355 /* Build an expression for the range test. */
4357 if (TREE_TYPE (name
) != TREE_TYPE (name2
))
4358 tmp
= build1 (NOP_EXPR
, TREE_TYPE (name
), tmp
);
4359 if (cst2
!= NULL_TREE
)
4360 tmp
= build2 (PLUS_EXPR
, TREE_TYPE (name
), tmp
, cst2
);
4364 fprintf (dump_file
, "Adding assert for ");
4365 print_generic_expr (dump_file
, name2
, 0);
4366 fprintf (dump_file
, " from ");
4367 print_generic_expr (dump_file
, tmp
, 0);
4368 fprintf (dump_file
, "\n");
4371 register_new_assert_for (name2
, tmp
, comp_code
, val
, NULL
, e
, bsi
);
4380 /* OP is an operand of a truth value expression which is known to have
4381 a particular value. Register any asserts for OP and for any
4382 operands in OP's defining statement.
4384 If CODE is EQ_EXPR, then we want to register OP is zero (false),
4385 if CODE is NE_EXPR, then we want to register OP is nonzero (true). */
4388 register_edge_assert_for_1 (tree op
, enum tree_code code
,
4389 edge e
, gimple_stmt_iterator bsi
)
4391 bool retval
= false;
4394 enum tree_code rhs_code
;
4396 /* We only care about SSA_NAMEs. */
4397 if (TREE_CODE (op
) != SSA_NAME
)
4400 /* We know that OP will have a zero or nonzero value. If OP is used
4401 more than once go ahead and register an assert for OP.
4403 The FOUND_IN_SUBGRAPH support is not helpful in this situation as
4404 it will always be set for OP (because OP is used in a COND_EXPR in
4406 if (!has_single_use (op
))
4408 val
= build_int_cst (TREE_TYPE (op
), 0);
4409 register_new_assert_for (op
, op
, code
, val
, NULL
, e
, bsi
);
4413 /* Now look at how OP is set. If it's set from a comparison,
4414 a truth operation or some bit operations, then we may be able
4415 to register information about the operands of that assignment. */
4416 op_def
= SSA_NAME_DEF_STMT (op
);
4417 if (gimple_code (op_def
) != GIMPLE_ASSIGN
)
4420 rhs_code
= gimple_assign_rhs_code (op_def
);
4422 if (TREE_CODE_CLASS (rhs_code
) == tcc_comparison
)
4424 bool invert
= (code
== EQ_EXPR
? true : false);
4425 tree op0
= gimple_assign_rhs1 (op_def
);
4426 tree op1
= gimple_assign_rhs2 (op_def
);
4428 if (TREE_CODE (op0
) == SSA_NAME
)
4429 retval
|= register_edge_assert_for_2 (op0
, e
, bsi
, rhs_code
, op0
, op1
,
4431 if (TREE_CODE (op1
) == SSA_NAME
)
4432 retval
|= register_edge_assert_for_2 (op1
, e
, bsi
, rhs_code
, op0
, op1
,
4435 else if ((code
== NE_EXPR
4436 && (gimple_assign_rhs_code (op_def
) == TRUTH_AND_EXPR
4437 || gimple_assign_rhs_code (op_def
) == BIT_AND_EXPR
))
4439 && (gimple_assign_rhs_code (op_def
) == TRUTH_OR_EXPR
4440 || gimple_assign_rhs_code (op_def
) == BIT_IOR_EXPR
)))
4442 /* Recurse on each operand. */
4443 retval
|= register_edge_assert_for_1 (gimple_assign_rhs1 (op_def
),
4445 retval
|= register_edge_assert_for_1 (gimple_assign_rhs2 (op_def
),
4448 else if (gimple_assign_rhs_code (op_def
) == TRUTH_NOT_EXPR
)
4450 /* Recurse, flipping CODE. */
4451 code
= invert_tree_comparison (code
, false);
4452 retval
|= register_edge_assert_for_1 (gimple_assign_rhs1 (op_def
),
4455 else if (gimple_assign_rhs_code (op_def
) == SSA_NAME
)
4457 /* Recurse through the copy. */
4458 retval
|= register_edge_assert_for_1 (gimple_assign_rhs1 (op_def
),
4461 else if (CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (op_def
)))
4463 /* Recurse through the type conversion. */
4464 retval
|= register_edge_assert_for_1 (gimple_assign_rhs1 (op_def
),
4471 /* Try to register an edge assertion for SSA name NAME on edge E for
4472 the condition COND contributing to the conditional jump pointed to by SI.
4473 Return true if an assertion for NAME could be registered. */
4476 register_edge_assert_for (tree name
, edge e
, gimple_stmt_iterator si
,
4477 enum tree_code cond_code
, tree cond_op0
,
4481 enum tree_code comp_code
;
4482 bool retval
= false;
4483 bool is_else_edge
= (e
->flags
& EDGE_FALSE_VALUE
) != 0;
4485 /* Do not attempt to infer anything in names that flow through
4487 if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (name
))
4490 if (!extract_code_and_val_from_cond_with_ops (name
, cond_code
,
4496 /* Register ASSERT_EXPRs for name. */
4497 retval
|= register_edge_assert_for_2 (name
, e
, si
, cond_code
, cond_op0
,
4498 cond_op1
, is_else_edge
);
4501 /* If COND is effectively an equality test of an SSA_NAME against
4502 the value zero or one, then we may be able to assert values
4503 for SSA_NAMEs which flow into COND. */
4505 /* In the case of NAME == 1 or NAME != 0, for TRUTH_AND_EXPR defining
4506 statement of NAME we can assert both operands of the TRUTH_AND_EXPR
4507 have nonzero value. */
4508 if (((comp_code
== EQ_EXPR
&& integer_onep (val
))
4509 || (comp_code
== NE_EXPR
&& integer_zerop (val
))))
4511 gimple def_stmt
= SSA_NAME_DEF_STMT (name
);
4513 if (is_gimple_assign (def_stmt
)
4514 && (gimple_assign_rhs_code (def_stmt
) == TRUTH_AND_EXPR
4515 || gimple_assign_rhs_code (def_stmt
) == BIT_AND_EXPR
))
4517 tree op0
= gimple_assign_rhs1 (def_stmt
);
4518 tree op1
= gimple_assign_rhs2 (def_stmt
);
4519 retval
|= register_edge_assert_for_1 (op0
, NE_EXPR
, e
, si
);
4520 retval
|= register_edge_assert_for_1 (op1
, NE_EXPR
, e
, si
);
4524 /* In the case of NAME == 0 or NAME != 1, for TRUTH_OR_EXPR defining
4525 statement of NAME we can assert both operands of the TRUTH_OR_EXPR
4527 if (((comp_code
== EQ_EXPR
&& integer_zerop (val
))
4528 || (comp_code
== NE_EXPR
&& integer_onep (val
))))
4530 gimple def_stmt
= SSA_NAME_DEF_STMT (name
);
4532 if (is_gimple_assign (def_stmt
)
4533 && (gimple_assign_rhs_code (def_stmt
) == TRUTH_OR_EXPR
4534 /* For BIT_IOR_EXPR only if NAME == 0 both operands have
4535 necessarily zero value. */
4536 || (comp_code
== EQ_EXPR
4537 && (gimple_assign_rhs_code (def_stmt
) == BIT_IOR_EXPR
))))
4539 tree op0
= gimple_assign_rhs1 (def_stmt
);
4540 tree op1
= gimple_assign_rhs2 (def_stmt
);
4541 retval
|= register_edge_assert_for_1 (op0
, EQ_EXPR
, e
, si
);
4542 retval
|= register_edge_assert_for_1 (op1
, EQ_EXPR
, e
, si
);
4550 /* Determine whether the outgoing edges of BB should receive an
4551 ASSERT_EXPR for each of the operands of BB's LAST statement.
4552 The last statement of BB must be a COND_EXPR.
4554 If any of the sub-graphs rooted at BB have an interesting use of
4555 the predicate operands, an assert location node is added to the
4556 list of assertions for the corresponding operands. */
4559 find_conditional_asserts (basic_block bb
, gimple last
)
4562 gimple_stmt_iterator bsi
;
4568 need_assert
= false;
4569 bsi
= gsi_for_stmt (last
);
4571 /* Look for uses of the operands in each of the sub-graphs
4572 rooted at BB. We need to check each of the outgoing edges
4573 separately, so that we know what kind of ASSERT_EXPR to
4575 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
4580 /* Register the necessary assertions for each operand in the
4581 conditional predicate. */
4582 FOR_EACH_SSA_TREE_OPERAND (op
, last
, iter
, SSA_OP_USE
)
4584 need_assert
|= register_edge_assert_for (op
, e
, bsi
,
4585 gimple_cond_code (last
),
4586 gimple_cond_lhs (last
),
4587 gimple_cond_rhs (last
));
4594 /* Compare two case labels sorting first by the destination label uid
4595 and then by the case value. */
4598 compare_case_labels (const void *p1
, const void *p2
)
4600 const_tree
const case1
= *(const_tree
const*)p1
;
4601 const_tree
const case2
= *(const_tree
const*)p2
;
4602 unsigned int uid1
= DECL_UID (CASE_LABEL (case1
));
4603 unsigned int uid2
= DECL_UID (CASE_LABEL (case2
));
4607 else if (uid1
== uid2
)
4609 /* Make sure the default label is first in a group. */
4610 if (!CASE_LOW (case1
))
4612 else if (!CASE_LOW (case2
))
4615 return tree_int_cst_compare (CASE_LOW (case1
), CASE_LOW (case2
));
4621 /* Determine whether the outgoing edges of BB should receive an
4622 ASSERT_EXPR for each of the operands of BB's LAST statement.
4623 The last statement of BB must be a SWITCH_EXPR.
4625 If any of the sub-graphs rooted at BB have an interesting use of
4626 the predicate operands, an assert location node is added to the
4627 list of assertions for the corresponding operands. */
4630 find_switch_asserts (basic_block bb
, gimple last
)
4633 gimple_stmt_iterator bsi
;
4637 size_t n
= gimple_switch_num_labels(last
);
4638 #if GCC_VERSION >= 4000
4641 /* Work around GCC 3.4 bug (PR 37086). */
4642 volatile unsigned int idx
;
4645 need_assert
= false;
4646 bsi
= gsi_for_stmt (last
);
4647 op
= gimple_switch_index (last
);
4648 if (TREE_CODE (op
) != SSA_NAME
)
4651 /* Build a vector of case labels sorted by destination label. */
4652 vec2
= make_tree_vec (n
);
4653 for (idx
= 0; idx
< n
; ++idx
)
4654 TREE_VEC_ELT (vec2
, idx
) = gimple_switch_label (last
, idx
);
4655 qsort (&TREE_VEC_ELT (vec2
, 0), n
, sizeof (tree
), compare_case_labels
);
4657 for (idx
= 0; idx
< n
; ++idx
)
4660 tree cl
= TREE_VEC_ELT (vec2
, idx
);
4662 min
= CASE_LOW (cl
);
4663 max
= CASE_HIGH (cl
);
4665 /* If there are multiple case labels with the same destination
4666 we need to combine them to a single value range for the edge. */
4668 && CASE_LABEL (cl
) == CASE_LABEL (TREE_VEC_ELT (vec2
, idx
+ 1)))
4670 /* Skip labels until the last of the group. */
4674 && CASE_LABEL (cl
) == CASE_LABEL (TREE_VEC_ELT (vec2
, idx
)));
4677 /* Pick up the maximum of the case label range. */
4678 if (CASE_HIGH (TREE_VEC_ELT (vec2
, idx
)))
4679 max
= CASE_HIGH (TREE_VEC_ELT (vec2
, idx
));
4681 max
= CASE_LOW (TREE_VEC_ELT (vec2
, idx
));
4684 /* Nothing to do if the range includes the default label until we
4685 can register anti-ranges. */
4686 if (min
== NULL_TREE
)
4689 /* Find the edge to register the assert expr on. */
4690 e
= find_edge (bb
, label_to_block (CASE_LABEL (cl
)));
4692 /* Register the necessary assertions for the operand in the
4694 need_assert
|= register_edge_assert_for (op
, e
, bsi
,
4695 max
? GE_EXPR
: EQ_EXPR
,
4697 fold_convert (TREE_TYPE (op
),
4701 need_assert
|= register_edge_assert_for (op
, e
, bsi
, LE_EXPR
,
4703 fold_convert (TREE_TYPE (op
),
4712 /* Traverse all the statements in block BB looking for statements that
4713 may generate useful assertions for the SSA names in their operand.
4714 If a statement produces a useful assertion A for name N_i, then the
4715 list of assertions already generated for N_i is scanned to
4716 determine if A is actually needed.
4718 If N_i already had the assertion A at a location dominating the
4719 current location, then nothing needs to be done. Otherwise, the
4720 new location for A is recorded instead.
4722 1- For every statement S in BB, all the variables used by S are
4723 added to bitmap FOUND_IN_SUBGRAPH.
4725 2- If statement S uses an operand N in a way that exposes a known
4726 value range for N, then if N was not already generated by an
4727 ASSERT_EXPR, create a new assert location for N. For instance,
4728 if N is a pointer and the statement dereferences it, we can
4729 assume that N is not NULL.
4731 3- COND_EXPRs are a special case of #2. We can derive range
4732 information from the predicate but need to insert different
4733 ASSERT_EXPRs for each of the sub-graphs rooted at the
4734 conditional block. If the last statement of BB is a conditional
4735 expression of the form 'X op Y', then
4737 a) Remove X and Y from the set FOUND_IN_SUBGRAPH.
4739 b) If the conditional is the only entry point to the sub-graph
4740 corresponding to the THEN_CLAUSE, recurse into it. On
4741 return, if X and/or Y are marked in FOUND_IN_SUBGRAPH, then
4742 an ASSERT_EXPR is added for the corresponding variable.
4744 c) Repeat step (b) on the ELSE_CLAUSE.
4746 d) Mark X and Y in FOUND_IN_SUBGRAPH.
4755 In this case, an assertion on the THEN clause is useful to
4756 determine that 'a' is always 9 on that edge. However, an assertion
4757 on the ELSE clause would be unnecessary.
4759 4- If BB does not end in a conditional expression, then we recurse
4760 into BB's dominator children.
4762 At the end of the recursive traversal, every SSA name will have a
4763 list of locations where ASSERT_EXPRs should be added. When a new
4764 location for name N is found, it is registered by calling
4765 register_new_assert_for. That function keeps track of all the
4766 registered assertions to prevent adding unnecessary assertions.
4767 For instance, if a pointer P_4 is dereferenced more than once in a
4768 dominator tree, only the location dominating all the dereference of
4769 P_4 will receive an ASSERT_EXPR.
4771 If this function returns true, then it means that there are names
4772 for which we need to generate ASSERT_EXPRs. Those assertions are
4773 inserted by process_assert_insertions. */
4776 find_assert_locations_1 (basic_block bb
, sbitmap live
)
4778 gimple_stmt_iterator si
;
4783 need_assert
= false;
4784 last
= last_stmt (bb
);
4786 /* If BB's last statement is a conditional statement involving integer
4787 operands, determine if we need to add ASSERT_EXPRs. */
4789 && gimple_code (last
) == GIMPLE_COND
4790 && !fp_predicate (last
)
4791 && !ZERO_SSA_OPERANDS (last
, SSA_OP_USE
))
4792 need_assert
|= find_conditional_asserts (bb
, last
);
4794 /* If BB's last statement is a switch statement involving integer
4795 operands, determine if we need to add ASSERT_EXPRs. */
4797 && gimple_code (last
) == GIMPLE_SWITCH
4798 && !ZERO_SSA_OPERANDS (last
, SSA_OP_USE
))
4799 need_assert
|= find_switch_asserts (bb
, last
);
4801 /* Traverse all the statements in BB marking used names and looking
4802 for statements that may infer assertions for their used operands. */
4803 for (si
= gsi_start_bb (bb
); !gsi_end_p (si
); gsi_next (&si
))
4809 stmt
= gsi_stmt (si
);
4811 if (is_gimple_debug (stmt
))
4814 /* See if we can derive an assertion for any of STMT's operands. */
4815 FOR_EACH_SSA_TREE_OPERAND (op
, stmt
, i
, SSA_OP_USE
)
4818 enum tree_code comp_code
;
4820 /* Mark OP in our live bitmap. */
4821 SET_BIT (live
, SSA_NAME_VERSION (op
));
4823 /* If OP is used in such a way that we can infer a value
4824 range for it, and we don't find a previous assertion for
4825 it, create a new assertion location node for OP. */
4826 if (infer_value_range (stmt
, op
, &comp_code
, &value
))
4828 /* If we are able to infer a nonzero value range for OP,
4829 then walk backwards through the use-def chain to see if OP
4830 was set via a typecast.
4832 If so, then we can also infer a nonzero value range
4833 for the operand of the NOP_EXPR. */
4834 if (comp_code
== NE_EXPR
&& integer_zerop (value
))
4837 gimple def_stmt
= SSA_NAME_DEF_STMT (t
);
4839 while (is_gimple_assign (def_stmt
)
4840 && gimple_assign_rhs_code (def_stmt
) == NOP_EXPR
4842 (gimple_assign_rhs1 (def_stmt
)) == SSA_NAME
4844 (TREE_TYPE (gimple_assign_rhs1 (def_stmt
))))
4846 t
= gimple_assign_rhs1 (def_stmt
);
4847 def_stmt
= SSA_NAME_DEF_STMT (t
);
4849 /* Note we want to register the assert for the
4850 operand of the NOP_EXPR after SI, not after the
4852 if (! has_single_use (t
))
4854 register_new_assert_for (t
, t
, comp_code
, value
,
4861 /* If OP is used only once, namely in this STMT, don't
4862 bother creating an ASSERT_EXPR for it. Such an
4863 ASSERT_EXPR would do nothing but increase compile time. */
4864 if (!has_single_use (op
))
4866 register_new_assert_for (op
, op
, comp_code
, value
,
4874 /* Traverse all PHI nodes in BB marking used operands. */
4875 for (si
= gsi_start_phis (bb
); !gsi_end_p(si
); gsi_next (&si
))
4877 use_operand_p arg_p
;
4879 phi
= gsi_stmt (si
);
4881 FOR_EACH_PHI_ARG (arg_p
, phi
, i
, SSA_OP_USE
)
4883 tree arg
= USE_FROM_PTR (arg_p
);
4884 if (TREE_CODE (arg
) == SSA_NAME
)
4885 SET_BIT (live
, SSA_NAME_VERSION (arg
));
4892 /* Do an RPO walk over the function computing SSA name liveness
4893 on-the-fly and deciding on assert expressions to insert.
4894 Returns true if there are assert expressions to be inserted. */
4897 find_assert_locations (void)
4899 int *rpo
= XCNEWVEC (int, last_basic_block
+ NUM_FIXED_BLOCKS
);
4900 int *bb_rpo
= XCNEWVEC (int, last_basic_block
+ NUM_FIXED_BLOCKS
);
4901 int *last_rpo
= XCNEWVEC (int, last_basic_block
+ NUM_FIXED_BLOCKS
);
4905 live
= XCNEWVEC (sbitmap
, last_basic_block
+ NUM_FIXED_BLOCKS
);
4906 rpo_cnt
= pre_and_rev_post_order_compute (NULL
, rpo
, false);
4907 for (i
= 0; i
< rpo_cnt
; ++i
)
4910 need_asserts
= false;
4911 for (i
= rpo_cnt
-1; i
>= 0; --i
)
4913 basic_block bb
= BASIC_BLOCK (rpo
[i
]);
4919 live
[rpo
[i
]] = sbitmap_alloc (num_ssa_names
);
4920 sbitmap_zero (live
[rpo
[i
]]);
4923 /* Process BB and update the live information with uses in
4925 need_asserts
|= find_assert_locations_1 (bb
, live
[rpo
[i
]]);
4927 /* Merge liveness into the predecessor blocks and free it. */
4928 if (!sbitmap_empty_p (live
[rpo
[i
]]))
4931 FOR_EACH_EDGE (e
, ei
, bb
->preds
)
4933 int pred
= e
->src
->index
;
4934 if (e
->flags
& EDGE_DFS_BACK
)
4939 live
[pred
] = sbitmap_alloc (num_ssa_names
);
4940 sbitmap_zero (live
[pred
]);
4942 sbitmap_a_or_b (live
[pred
], live
[pred
], live
[rpo
[i
]]);
4944 if (bb_rpo
[pred
] < pred_rpo
)
4945 pred_rpo
= bb_rpo
[pred
];
4948 /* Record the RPO number of the last visited block that needs
4949 live information from this block. */
4950 last_rpo
[rpo
[i
]] = pred_rpo
;
4954 sbitmap_free (live
[rpo
[i
]]);
4955 live
[rpo
[i
]] = NULL
;
4958 /* We can free all successors live bitmaps if all their
4959 predecessors have been visited already. */
4960 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
4961 if (last_rpo
[e
->dest
->index
] == i
4962 && live
[e
->dest
->index
])
4964 sbitmap_free (live
[e
->dest
->index
]);
4965 live
[e
->dest
->index
] = NULL
;
4970 XDELETEVEC (bb_rpo
);
4971 XDELETEVEC (last_rpo
);
4972 for (i
= 0; i
< last_basic_block
+ NUM_FIXED_BLOCKS
; ++i
)
4974 sbitmap_free (live
[i
]);
4977 return need_asserts
;
4980 /* Create an ASSERT_EXPR for NAME and insert it in the location
4981 indicated by LOC. Return true if we made any edge insertions. */
4984 process_assert_insertions_for (tree name
, assert_locus_t loc
)
4986 /* Build the comparison expression NAME_i COMP_CODE VAL. */
4993 /* If we have X <=> X do not insert an assert expr for that. */
4994 if (loc
->expr
== loc
->val
)
4997 cond
= build2 (loc
->comp_code
, boolean_type_node
, loc
->expr
, loc
->val
);
4998 assert_stmt
= build_assert_expr_for (cond
, name
);
5001 /* We have been asked to insert the assertion on an edge. This
5002 is used only by COND_EXPR and SWITCH_EXPR assertions. */
5003 #if defined ENABLE_CHECKING
5004 gcc_assert (gimple_code (gsi_stmt (loc
->si
)) == GIMPLE_COND
5005 || gimple_code (gsi_stmt (loc
->si
)) == GIMPLE_SWITCH
);
5008 gsi_insert_on_edge (loc
->e
, assert_stmt
);
5012 /* Otherwise, we can insert right after LOC->SI iff the
5013 statement must not be the last statement in the block. */
5014 stmt
= gsi_stmt (loc
->si
);
5015 if (!stmt_ends_bb_p (stmt
))
5017 gsi_insert_after (&loc
->si
, assert_stmt
, GSI_SAME_STMT
);
5021 /* If STMT must be the last statement in BB, we can only insert new
5022 assertions on the non-abnormal edge out of BB. Note that since
5023 STMT is not control flow, there may only be one non-abnormal edge
5025 FOR_EACH_EDGE (e
, ei
, loc
->bb
->succs
)
5026 if (!(e
->flags
& EDGE_ABNORMAL
))
5028 gsi_insert_on_edge (e
, assert_stmt
);
5036 /* Process all the insertions registered for every name N_i registered
5037 in NEED_ASSERT_FOR. The list of assertions to be inserted are
5038 found in ASSERTS_FOR[i]. */
5041 process_assert_insertions (void)
5045 bool update_edges_p
= false;
5046 int num_asserts
= 0;
5048 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
5049 dump_all_asserts (dump_file
);
5051 EXECUTE_IF_SET_IN_BITMAP (need_assert_for
, 0, i
, bi
)
5053 assert_locus_t loc
= asserts_for
[i
];
5058 assert_locus_t next
= loc
->next
;
5059 update_edges_p
|= process_assert_insertions_for (ssa_name (i
), loc
);
5067 gsi_commit_edge_inserts ();
5069 statistics_counter_event (cfun
, "Number of ASSERT_EXPR expressions inserted",
5074 /* Traverse the flowgraph looking for conditional jumps to insert range
5075 expressions. These range expressions are meant to provide information
5076 to optimizations that need to reason in terms of value ranges. They
5077 will not be expanded into RTL. For instance, given:
5086 this pass will transform the code into:
5092 x = ASSERT_EXPR <x, x < y>
5097 y = ASSERT_EXPR <y, x <= y>
5101 The idea is that once copy and constant propagation have run, other
5102 optimizations will be able to determine what ranges of values can 'x'
5103 take in different paths of the code, simply by checking the reaching
5104 definition of 'x'. */
5107 insert_range_assertions (void)
5109 need_assert_for
= BITMAP_ALLOC (NULL
);
5110 asserts_for
= XCNEWVEC (assert_locus_t
, num_ssa_names
);
5112 calculate_dominance_info (CDI_DOMINATORS
);
5114 if (find_assert_locations ())
5116 process_assert_insertions ();
5117 update_ssa (TODO_update_ssa_no_phi
);
5120 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
5122 fprintf (dump_file
, "\nSSA form after inserting ASSERT_EXPRs\n");
5123 dump_function_to_file (current_function_decl
, dump_file
, dump_flags
);
5127 BITMAP_FREE (need_assert_for
);
5130 /* Checks one ARRAY_REF in REF, located at LOCUS. Ignores flexible arrays
5131 and "struct" hacks. If VRP can determine that the
5132 array subscript is a constant, check if it is outside valid
5133 range. If the array subscript is a RANGE, warn if it is
5134 non-overlapping with valid range.
5135 IGNORE_OFF_BY_ONE is true if the ARRAY_REF is inside a ADDR_EXPR. */
5138 check_array_ref (location_t location
, tree ref
, bool ignore_off_by_one
)
5140 value_range_t
* vr
= NULL
;
5141 tree low_sub
, up_sub
;
5142 tree low_bound
, up_bound
, up_bound_p1
;
5145 if (TREE_NO_WARNING (ref
))
5148 low_sub
= up_sub
= TREE_OPERAND (ref
, 1);
5149 up_bound
= array_ref_up_bound (ref
);
5151 /* Can not check flexible arrays. */
5153 || TREE_CODE (up_bound
) != INTEGER_CST
)
5156 /* Accesses to trailing arrays via pointers may access storage
5157 beyond the types array bounds. */
5158 base
= get_base_address (ref
);
5159 if (base
&& TREE_CODE (base
) == MEM_REF
)
5161 tree cref
, next
= NULL_TREE
;
5163 if (TREE_CODE (TREE_OPERAND (ref
, 0)) != COMPONENT_REF
)
5166 cref
= TREE_OPERAND (ref
, 0);
5167 if (TREE_CODE (TREE_TYPE (TREE_OPERAND (cref
, 0))) == RECORD_TYPE
)
5168 for (next
= DECL_CHAIN (TREE_OPERAND (cref
, 1));
5169 next
&& TREE_CODE (next
) != FIELD_DECL
;
5170 next
= DECL_CHAIN (next
))
5173 /* If this is the last field in a struct type or a field in a
5174 union type do not warn. */
5179 low_bound
= array_ref_low_bound (ref
);
5180 up_bound_p1
= int_const_binop (PLUS_EXPR
, up_bound
, integer_one_node
, 0);
5182 if (TREE_CODE (low_sub
) == SSA_NAME
)
5184 vr
= get_value_range (low_sub
);
5185 if (vr
->type
== VR_RANGE
|| vr
->type
== VR_ANTI_RANGE
)
5187 low_sub
= vr
->type
== VR_RANGE
? vr
->max
: vr
->min
;
5188 up_sub
= vr
->type
== VR_RANGE
? vr
->min
: vr
->max
;
5192 if (vr
&& vr
->type
== VR_ANTI_RANGE
)
5194 if (TREE_CODE (up_sub
) == INTEGER_CST
5195 && tree_int_cst_lt (up_bound
, up_sub
)
5196 && TREE_CODE (low_sub
) == INTEGER_CST
5197 && tree_int_cst_lt (low_sub
, low_bound
))
5199 warning_at (location
, OPT_Warray_bounds
,
5200 "array subscript is outside array bounds");
5201 TREE_NO_WARNING (ref
) = 1;
5204 else if (TREE_CODE (up_sub
) == INTEGER_CST
5205 && (ignore_off_by_one
5206 ? (tree_int_cst_lt (up_bound
, up_sub
)
5207 && !tree_int_cst_equal (up_bound_p1
, up_sub
))
5208 : (tree_int_cst_lt (up_bound
, up_sub
)
5209 || tree_int_cst_equal (up_bound_p1
, up_sub
))))
5211 warning_at (location
, OPT_Warray_bounds
,
5212 "array subscript is above array bounds");
5213 TREE_NO_WARNING (ref
) = 1;
5215 else if (TREE_CODE (low_sub
) == INTEGER_CST
5216 && tree_int_cst_lt (low_sub
, low_bound
))
5218 warning_at (location
, OPT_Warray_bounds
,
5219 "array subscript is below array bounds");
5220 TREE_NO_WARNING (ref
) = 1;
5224 /* Searches if the expr T, located at LOCATION computes
5225 address of an ARRAY_REF, and call check_array_ref on it. */
5228 search_for_addr_array (tree t
, location_t location
)
5230 while (TREE_CODE (t
) == SSA_NAME
)
5232 gimple g
= SSA_NAME_DEF_STMT (t
);
5234 if (gimple_code (g
) != GIMPLE_ASSIGN
)
5237 if (get_gimple_rhs_class (gimple_assign_rhs_code (g
))
5238 != GIMPLE_SINGLE_RHS
)
5241 t
= gimple_assign_rhs1 (g
);
5245 /* We are only interested in addresses of ARRAY_REF's. */
5246 if (TREE_CODE (t
) != ADDR_EXPR
)
5249 /* Check each ARRAY_REFs in the reference chain. */
5252 if (TREE_CODE (t
) == ARRAY_REF
)
5253 check_array_ref (location
, t
, true /*ignore_off_by_one*/);
5255 t
= TREE_OPERAND (t
, 0);
5257 while (handled_component_p (t
));
5259 if (TREE_CODE (t
) == MEM_REF
5260 && TREE_CODE (TREE_OPERAND (t
, 0)) == ADDR_EXPR
5261 && !TREE_NO_WARNING (t
))
5263 tree tem
= TREE_OPERAND (TREE_OPERAND (t
, 0), 0);
5264 tree low_bound
, up_bound
, el_sz
;
5266 if (TREE_CODE (TREE_TYPE (tem
)) != ARRAY_TYPE
5267 || TREE_CODE (TREE_TYPE (TREE_TYPE (tem
))) == ARRAY_TYPE
5268 || !TYPE_DOMAIN (TREE_TYPE (tem
)))
5271 low_bound
= TYPE_MIN_VALUE (TYPE_DOMAIN (TREE_TYPE (tem
)));
5272 up_bound
= TYPE_MAX_VALUE (TYPE_DOMAIN (TREE_TYPE (tem
)));
5273 el_sz
= TYPE_SIZE_UNIT (TREE_TYPE (TREE_TYPE (tem
)));
5275 || TREE_CODE (low_bound
) != INTEGER_CST
5277 || TREE_CODE (up_bound
) != INTEGER_CST
5279 || TREE_CODE (el_sz
) != INTEGER_CST
)
5282 idx
= mem_ref_offset (t
);
5283 idx
= double_int_sdiv (idx
, tree_to_double_int (el_sz
), TRUNC_DIV_EXPR
);
5284 if (double_int_scmp (idx
, double_int_zero
) < 0)
5286 warning_at (location
, OPT_Warray_bounds
,
5287 "array subscript is below array bounds");
5288 TREE_NO_WARNING (t
) = 1;
5290 else if (double_int_scmp (idx
,
5293 (tree_to_double_int (up_bound
),
5295 (tree_to_double_int (low_bound
))),
5296 double_int_one
)) > 0)
5298 warning_at (location
, OPT_Warray_bounds
,
5299 "array subscript is above array bounds");
5300 TREE_NO_WARNING (t
) = 1;
5305 /* walk_tree() callback that checks if *TP is
5306 an ARRAY_REF inside an ADDR_EXPR (in which an array
5307 subscript one outside the valid range is allowed). Call
5308 check_array_ref for each ARRAY_REF found. The location is
5312 check_array_bounds (tree
*tp
, int *walk_subtree
, void *data
)
5315 struct walk_stmt_info
*wi
= (struct walk_stmt_info
*) data
;
5316 location_t location
;
5318 if (EXPR_HAS_LOCATION (t
))
5319 location
= EXPR_LOCATION (t
);
5322 location_t
*locp
= (location_t
*) wi
->info
;
5326 *walk_subtree
= TRUE
;
5328 if (TREE_CODE (t
) == ARRAY_REF
)
5329 check_array_ref (location
, t
, false /*ignore_off_by_one*/);
5331 if (TREE_CODE (t
) == MEM_REF
5332 || (TREE_CODE (t
) == RETURN_EXPR
&& TREE_OPERAND (t
, 0)))
5333 search_for_addr_array (TREE_OPERAND (t
, 0), location
);
5335 if (TREE_CODE (t
) == ADDR_EXPR
)
5336 *walk_subtree
= FALSE
;
5341 /* Walk over all statements of all reachable BBs and call check_array_bounds
5345 check_all_array_refs (void)
5348 gimple_stmt_iterator si
;
5354 bool executable
= false;
5356 /* Skip blocks that were found to be unreachable. */
5357 FOR_EACH_EDGE (e
, ei
, bb
->preds
)
5358 executable
|= !!(e
->flags
& EDGE_EXECUTABLE
);
5362 for (si
= gsi_start_bb (bb
); !gsi_end_p (si
); gsi_next (&si
))
5364 gimple stmt
= gsi_stmt (si
);
5365 struct walk_stmt_info wi
;
5366 if (!gimple_has_location (stmt
))
5369 if (is_gimple_call (stmt
))
5372 size_t n
= gimple_call_num_args (stmt
);
5373 for (i
= 0; i
< n
; i
++)
5375 tree arg
= gimple_call_arg (stmt
, i
);
5376 search_for_addr_array (arg
, gimple_location (stmt
));
5381 memset (&wi
, 0, sizeof (wi
));
5382 wi
.info
= CONST_CAST (void *, (const void *)
5383 gimple_location_ptr (stmt
));
5385 walk_gimple_op (gsi_stmt (si
),
5393 /* Convert range assertion expressions into the implied copies and
5394 copy propagate away the copies. Doing the trivial copy propagation
5395 here avoids the need to run the full copy propagation pass after
5398 FIXME, this will eventually lead to copy propagation removing the
5399 names that had useful range information attached to them. For
5400 instance, if we had the assertion N_i = ASSERT_EXPR <N_j, N_j > 3>,
5401 then N_i will have the range [3, +INF].
5403 However, by converting the assertion into the implied copy
5404 operation N_i = N_j, we will then copy-propagate N_j into the uses
5405 of N_i and lose the range information. We may want to hold on to
5406 ASSERT_EXPRs a little while longer as the ranges could be used in
5407 things like jump threading.
5409 The problem with keeping ASSERT_EXPRs around is that passes after
5410 VRP need to handle them appropriately.
5412 Another approach would be to make the range information a first
5413 class property of the SSA_NAME so that it can be queried from
5414 any pass. This is made somewhat more complex by the need for
5415 multiple ranges to be associated with one SSA_NAME. */
5418 remove_range_assertions (void)
5421 gimple_stmt_iterator si
;
5423 /* Note that the BSI iterator bump happens at the bottom of the
5424 loop and no bump is necessary if we're removing the statement
5425 referenced by the current BSI. */
5427 for (si
= gsi_start_bb (bb
); !gsi_end_p (si
);)
5429 gimple stmt
= gsi_stmt (si
);
5432 if (is_gimple_assign (stmt
)
5433 && gimple_assign_rhs_code (stmt
) == ASSERT_EXPR
)
5435 tree rhs
= gimple_assign_rhs1 (stmt
);
5437 tree cond
= fold (ASSERT_EXPR_COND (rhs
));
5438 use_operand_p use_p
;
5439 imm_use_iterator iter
;
5441 gcc_assert (cond
!= boolean_false_node
);
5443 /* Propagate the RHS into every use of the LHS. */
5444 var
= ASSERT_EXPR_VAR (rhs
);
5445 FOR_EACH_IMM_USE_STMT (use_stmt
, iter
,
5446 gimple_assign_lhs (stmt
))
5447 FOR_EACH_IMM_USE_ON_STMT (use_p
, iter
)
5449 SET_USE (use_p
, var
);
5450 gcc_assert (TREE_CODE (var
) == SSA_NAME
);
5453 /* And finally, remove the copy, it is not needed. */
5454 gsi_remove (&si
, true);
5455 release_defs (stmt
);
5463 /* Return true if STMT is interesting for VRP. */
5466 stmt_interesting_for_vrp (gimple stmt
)
5468 if (gimple_code (stmt
) == GIMPLE_PHI
5469 && is_gimple_reg (gimple_phi_result (stmt
))
5470 && (INTEGRAL_TYPE_P (TREE_TYPE (gimple_phi_result (stmt
)))
5471 || POINTER_TYPE_P (TREE_TYPE (gimple_phi_result (stmt
)))))
5473 else if (is_gimple_assign (stmt
) || is_gimple_call (stmt
))
5475 tree lhs
= gimple_get_lhs (stmt
);
5477 /* In general, assignments with virtual operands are not useful
5478 for deriving ranges, with the obvious exception of calls to
5479 builtin functions. */
5480 if (lhs
&& TREE_CODE (lhs
) == SSA_NAME
5481 && (INTEGRAL_TYPE_P (TREE_TYPE (lhs
))
5482 || POINTER_TYPE_P (TREE_TYPE (lhs
)))
5483 && ((is_gimple_call (stmt
)
5484 && gimple_call_fndecl (stmt
) != NULL_TREE
5485 && DECL_IS_BUILTIN (gimple_call_fndecl (stmt
)))
5486 || !gimple_vuse (stmt
)))
5489 else if (gimple_code (stmt
) == GIMPLE_COND
5490 || gimple_code (stmt
) == GIMPLE_SWITCH
)
5497 /* Initialize local data structures for VRP. */
5500 vrp_initialize (void)
5504 vr_value
= XCNEWVEC (value_range_t
*, num_ssa_names
);
5505 vr_phi_edge_counts
= XCNEWVEC (int, num_ssa_names
);
5509 gimple_stmt_iterator si
;
5511 for (si
= gsi_start_phis (bb
); !gsi_end_p (si
); gsi_next (&si
))
5513 gimple phi
= gsi_stmt (si
);
5514 if (!stmt_interesting_for_vrp (phi
))
5516 tree lhs
= PHI_RESULT (phi
);
5517 set_value_range_to_varying (get_value_range (lhs
));
5518 prop_set_simulate_again (phi
, false);
5521 prop_set_simulate_again (phi
, true);
5524 for (si
= gsi_start_bb (bb
); !gsi_end_p (si
); gsi_next (&si
))
5526 gimple stmt
= gsi_stmt (si
);
5528 /* If the statement is a control insn, then we do not
5529 want to avoid simulating the statement once. Failure
5530 to do so means that those edges will never get added. */
5531 if (stmt_ends_bb_p (stmt
))
5532 prop_set_simulate_again (stmt
, true);
5533 else if (!stmt_interesting_for_vrp (stmt
))
5537 FOR_EACH_SSA_TREE_OPERAND (def
, stmt
, i
, SSA_OP_DEF
)
5538 set_value_range_to_varying (get_value_range (def
));
5539 prop_set_simulate_again (stmt
, false);
5542 prop_set_simulate_again (stmt
, true);
5548 /* Visit assignment STMT. If it produces an interesting range, record
5549 the SSA name in *OUTPUT_P. */
5551 static enum ssa_prop_result
5552 vrp_visit_assignment_or_call (gimple stmt
, tree
*output_p
)
5556 enum gimple_code code
= gimple_code (stmt
);
5557 lhs
= gimple_get_lhs (stmt
);
5559 /* We only keep track of ranges in integral and pointer types. */
5560 if (TREE_CODE (lhs
) == SSA_NAME
5561 && ((INTEGRAL_TYPE_P (TREE_TYPE (lhs
))
5562 /* It is valid to have NULL MIN/MAX values on a type. See
5563 build_range_type. */
5564 && TYPE_MIN_VALUE (TREE_TYPE (lhs
))
5565 && TYPE_MAX_VALUE (TREE_TYPE (lhs
)))
5566 || POINTER_TYPE_P (TREE_TYPE (lhs
))))
5568 value_range_t new_vr
= { VR_UNDEFINED
, NULL_TREE
, NULL_TREE
, NULL
};
5570 if (code
== GIMPLE_CALL
)
5571 extract_range_basic (&new_vr
, stmt
);
5573 extract_range_from_assignment (&new_vr
, stmt
);
5575 if (update_value_range (lhs
, &new_vr
))
5579 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
5581 fprintf (dump_file
, "Found new range for ");
5582 print_generic_expr (dump_file
, lhs
, 0);
5583 fprintf (dump_file
, ": ");
5584 dump_value_range (dump_file
, &new_vr
);
5585 fprintf (dump_file
, "\n\n");
5588 if (new_vr
.type
== VR_VARYING
)
5589 return SSA_PROP_VARYING
;
5591 return SSA_PROP_INTERESTING
;
5594 return SSA_PROP_NOT_INTERESTING
;
5597 /* Every other statement produces no useful ranges. */
5598 FOR_EACH_SSA_TREE_OPERAND (def
, stmt
, iter
, SSA_OP_DEF
)
5599 set_value_range_to_varying (get_value_range (def
));
5601 return SSA_PROP_VARYING
;
5604 /* Helper that gets the value range of the SSA_NAME with version I
5605 or a symbolic range containing the SSA_NAME only if the value range
5606 is varying or undefined. */
5608 static inline value_range_t
5609 get_vr_for_comparison (int i
)
5611 value_range_t vr
= *(vr_value
[i
]);
5613 /* If name N_i does not have a valid range, use N_i as its own
5614 range. This allows us to compare against names that may
5615 have N_i in their ranges. */
5616 if (vr
.type
== VR_VARYING
|| vr
.type
== VR_UNDEFINED
)
5619 vr
.min
= ssa_name (i
);
5620 vr
.max
= ssa_name (i
);
5626 /* Compare all the value ranges for names equivalent to VAR with VAL
5627 using comparison code COMP. Return the same value returned by
5628 compare_range_with_value, including the setting of
5629 *STRICT_OVERFLOW_P. */
5632 compare_name_with_value (enum tree_code comp
, tree var
, tree val
,
5633 bool *strict_overflow_p
)
5639 int used_strict_overflow
;
5641 value_range_t equiv_vr
;
5643 /* Get the set of equivalences for VAR. */
5644 e
= get_value_range (var
)->equiv
;
5646 /* Start at -1. Set it to 0 if we do a comparison without relying
5647 on overflow, or 1 if all comparisons rely on overflow. */
5648 used_strict_overflow
= -1;
5650 /* Compare vars' value range with val. */
5651 equiv_vr
= get_vr_for_comparison (SSA_NAME_VERSION (var
));
5653 retval
= compare_range_with_value (comp
, &equiv_vr
, val
, &sop
);
5655 used_strict_overflow
= sop
? 1 : 0;
5657 /* If the equiv set is empty we have done all work we need to do. */
5661 && used_strict_overflow
> 0)
5662 *strict_overflow_p
= true;
5666 EXECUTE_IF_SET_IN_BITMAP (e
, 0, i
, bi
)
5668 equiv_vr
= get_vr_for_comparison (i
);
5670 t
= compare_range_with_value (comp
, &equiv_vr
, val
, &sop
);
5673 /* If we get different answers from different members
5674 of the equivalence set this check must be in a dead
5675 code region. Folding it to a trap representation
5676 would be correct here. For now just return don't-know. */
5686 used_strict_overflow
= 0;
5687 else if (used_strict_overflow
< 0)
5688 used_strict_overflow
= 1;
5693 && used_strict_overflow
> 0)
5694 *strict_overflow_p
= true;
5700 /* Given a comparison code COMP and names N1 and N2, compare all the
5701 ranges equivalent to N1 against all the ranges equivalent to N2
5702 to determine the value of N1 COMP N2. Return the same value
5703 returned by compare_ranges. Set *STRICT_OVERFLOW_P to indicate
5704 whether we relied on an overflow infinity in the comparison. */
5708 compare_names (enum tree_code comp
, tree n1
, tree n2
,
5709 bool *strict_overflow_p
)
5713 bitmap_iterator bi1
, bi2
;
5715 int used_strict_overflow
;
5716 static bitmap_obstack
*s_obstack
= NULL
;
5717 static bitmap s_e1
= NULL
, s_e2
= NULL
;
5719 /* Compare the ranges of every name equivalent to N1 against the
5720 ranges of every name equivalent to N2. */
5721 e1
= get_value_range (n1
)->equiv
;
5722 e2
= get_value_range (n2
)->equiv
;
5724 /* Use the fake bitmaps if e1 or e2 are not available. */
5725 if (s_obstack
== NULL
)
5727 s_obstack
= XNEW (bitmap_obstack
);
5728 bitmap_obstack_initialize (s_obstack
);
5729 s_e1
= BITMAP_ALLOC (s_obstack
);
5730 s_e2
= BITMAP_ALLOC (s_obstack
);
5737 /* Add N1 and N2 to their own set of equivalences to avoid
5738 duplicating the body of the loop just to check N1 and N2
5740 bitmap_set_bit (e1
, SSA_NAME_VERSION (n1
));
5741 bitmap_set_bit (e2
, SSA_NAME_VERSION (n2
));
5743 /* If the equivalence sets have a common intersection, then the two
5744 names can be compared without checking their ranges. */
5745 if (bitmap_intersect_p (e1
, e2
))
5747 bitmap_clear_bit (e1
, SSA_NAME_VERSION (n1
));
5748 bitmap_clear_bit (e2
, SSA_NAME_VERSION (n2
));
5750 return (comp
== EQ_EXPR
|| comp
== GE_EXPR
|| comp
== LE_EXPR
)
5752 : boolean_false_node
;
5755 /* Start at -1. Set it to 0 if we do a comparison without relying
5756 on overflow, or 1 if all comparisons rely on overflow. */
5757 used_strict_overflow
= -1;
5759 /* Otherwise, compare all the equivalent ranges. First, add N1 and
5760 N2 to their own set of equivalences to avoid duplicating the body
5761 of the loop just to check N1 and N2 ranges. */
5762 EXECUTE_IF_SET_IN_BITMAP (e1
, 0, i1
, bi1
)
5764 value_range_t vr1
= get_vr_for_comparison (i1
);
5766 t
= retval
= NULL_TREE
;
5767 EXECUTE_IF_SET_IN_BITMAP (e2
, 0, i2
, bi2
)
5771 value_range_t vr2
= get_vr_for_comparison (i2
);
5773 t
= compare_ranges (comp
, &vr1
, &vr2
, &sop
);
5776 /* If we get different answers from different members
5777 of the equivalence set this check must be in a dead
5778 code region. Folding it to a trap representation
5779 would be correct here. For now just return don't-know. */
5783 bitmap_clear_bit (e1
, SSA_NAME_VERSION (n1
));
5784 bitmap_clear_bit (e2
, SSA_NAME_VERSION (n2
));
5790 used_strict_overflow
= 0;
5791 else if (used_strict_overflow
< 0)
5792 used_strict_overflow
= 1;
5798 bitmap_clear_bit (e1
, SSA_NAME_VERSION (n1
));
5799 bitmap_clear_bit (e2
, SSA_NAME_VERSION (n2
));
5800 if (used_strict_overflow
> 0)
5801 *strict_overflow_p
= true;
5806 /* None of the equivalent ranges are useful in computing this
5808 bitmap_clear_bit (e1
, SSA_NAME_VERSION (n1
));
5809 bitmap_clear_bit (e2
, SSA_NAME_VERSION (n2
));
5813 /* Helper function for vrp_evaluate_conditional_warnv. */
5816 vrp_evaluate_conditional_warnv_with_ops_using_ranges (enum tree_code code
,
5818 bool * strict_overflow_p
)
5820 value_range_t
*vr0
, *vr1
;
5822 vr0
= (TREE_CODE (op0
) == SSA_NAME
) ? get_value_range (op0
) : NULL
;
5823 vr1
= (TREE_CODE (op1
) == SSA_NAME
) ? get_value_range (op1
) : NULL
;
5826 return compare_ranges (code
, vr0
, vr1
, strict_overflow_p
);
5827 else if (vr0
&& vr1
== NULL
)
5828 return compare_range_with_value (code
, vr0
, op1
, strict_overflow_p
);
5829 else if (vr0
== NULL
&& vr1
)
5830 return (compare_range_with_value
5831 (swap_tree_comparison (code
), vr1
, op0
, strict_overflow_p
));
5835 /* Helper function for vrp_evaluate_conditional_warnv. */
5838 vrp_evaluate_conditional_warnv_with_ops (enum tree_code code
, tree op0
,
5839 tree op1
, bool use_equiv_p
,
5840 bool *strict_overflow_p
, bool *only_ranges
)
5844 *only_ranges
= true;
5846 /* We only deal with integral and pointer types. */
5847 if (!INTEGRAL_TYPE_P (TREE_TYPE (op0
))
5848 && !POINTER_TYPE_P (TREE_TYPE (op0
)))
5854 && (ret
= vrp_evaluate_conditional_warnv_with_ops_using_ranges
5855 (code
, op0
, op1
, strict_overflow_p
)))
5857 *only_ranges
= false;
5858 if (TREE_CODE (op0
) == SSA_NAME
&& TREE_CODE (op1
) == SSA_NAME
)
5859 return compare_names (code
, op0
, op1
, strict_overflow_p
);
5860 else if (TREE_CODE (op0
) == SSA_NAME
)
5861 return compare_name_with_value (code
, op0
, op1
, strict_overflow_p
);
5862 else if (TREE_CODE (op1
) == SSA_NAME
)
5863 return (compare_name_with_value
5864 (swap_tree_comparison (code
), op1
, op0
, strict_overflow_p
));
5867 return vrp_evaluate_conditional_warnv_with_ops_using_ranges (code
, op0
, op1
,
5872 /* Given (CODE OP0 OP1) within STMT, try to simplify it based on value range
5873 information. Return NULL if the conditional can not be evaluated.
5874 The ranges of all the names equivalent with the operands in COND
5875 will be used when trying to compute the value. If the result is
5876 based on undefined signed overflow, issue a warning if
5880 vrp_evaluate_conditional (enum tree_code code
, tree op0
, tree op1
, gimple stmt
)
5886 /* Some passes and foldings leak constants with overflow flag set
5887 into the IL. Avoid doing wrong things with these and bail out. */
5888 if ((TREE_CODE (op0
) == INTEGER_CST
5889 && TREE_OVERFLOW (op0
))
5890 || (TREE_CODE (op1
) == INTEGER_CST
5891 && TREE_OVERFLOW (op1
)))
5895 ret
= vrp_evaluate_conditional_warnv_with_ops (code
, op0
, op1
, true, &sop
,
5900 enum warn_strict_overflow_code wc
;
5901 const char* warnmsg
;
5903 if (is_gimple_min_invariant (ret
))
5905 wc
= WARN_STRICT_OVERFLOW_CONDITIONAL
;
5906 warnmsg
= G_("assuming signed overflow does not occur when "
5907 "simplifying conditional to constant");
5911 wc
= WARN_STRICT_OVERFLOW_COMPARISON
;
5912 warnmsg
= G_("assuming signed overflow does not occur when "
5913 "simplifying conditional");
5916 if (issue_strict_overflow_warning (wc
))
5918 location_t location
;
5920 if (!gimple_has_location (stmt
))
5921 location
= input_location
;
5923 location
= gimple_location (stmt
);
5924 warning_at (location
, OPT_Wstrict_overflow
, "%s", warnmsg
);
5928 if (warn_type_limits
5929 && ret
&& only_ranges
5930 && TREE_CODE_CLASS (code
) == tcc_comparison
5931 && TREE_CODE (op0
) == SSA_NAME
)
5933 /* If the comparison is being folded and the operand on the LHS
5934 is being compared against a constant value that is outside of
5935 the natural range of OP0's type, then the predicate will
5936 always fold regardless of the value of OP0. If -Wtype-limits
5937 was specified, emit a warning. */
5938 tree type
= TREE_TYPE (op0
);
5939 value_range_t
*vr0
= get_value_range (op0
);
5941 if (vr0
->type
!= VR_VARYING
5942 && INTEGRAL_TYPE_P (type
)
5943 && vrp_val_is_min (vr0
->min
)
5944 && vrp_val_is_max (vr0
->max
)
5945 && is_gimple_min_invariant (op1
))
5947 location_t location
;
5949 if (!gimple_has_location (stmt
))
5950 location
= input_location
;
5952 location
= gimple_location (stmt
);
5954 warning_at (location
, OPT_Wtype_limits
,
5956 ? G_("comparison always false "
5957 "due to limited range of data type")
5958 : G_("comparison always true "
5959 "due to limited range of data type"));
5967 /* Visit conditional statement STMT. If we can determine which edge
5968 will be taken out of STMT's basic block, record it in
5969 *TAKEN_EDGE_P and return SSA_PROP_INTERESTING. Otherwise, return
5970 SSA_PROP_VARYING. */
5972 static enum ssa_prop_result
5973 vrp_visit_cond_stmt (gimple stmt
, edge
*taken_edge_p
)
5978 *taken_edge_p
= NULL
;
5980 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
5985 fprintf (dump_file
, "\nVisiting conditional with predicate: ");
5986 print_gimple_stmt (dump_file
, stmt
, 0, 0);
5987 fprintf (dump_file
, "\nWith known ranges\n");
5989 FOR_EACH_SSA_TREE_OPERAND (use
, stmt
, i
, SSA_OP_USE
)
5991 fprintf (dump_file
, "\t");
5992 print_generic_expr (dump_file
, use
, 0);
5993 fprintf (dump_file
, ": ");
5994 dump_value_range (dump_file
, vr_value
[SSA_NAME_VERSION (use
)]);
5997 fprintf (dump_file
, "\n");
6000 /* Compute the value of the predicate COND by checking the known
6001 ranges of each of its operands.
6003 Note that we cannot evaluate all the equivalent ranges here
6004 because those ranges may not yet be final and with the current
6005 propagation strategy, we cannot determine when the value ranges
6006 of the names in the equivalence set have changed.
6008 For instance, given the following code fragment
6012 i_14 = ASSERT_EXPR <i_5, i_5 != 0>
6016 Assume that on the first visit to i_14, i_5 has the temporary
6017 range [8, 8] because the second argument to the PHI function is
6018 not yet executable. We derive the range ~[0, 0] for i_14 and the
6019 equivalence set { i_5 }. So, when we visit 'if (i_14 == 1)' for
6020 the first time, since i_14 is equivalent to the range [8, 8], we
6021 determine that the predicate is always false.
6023 On the next round of propagation, i_13 is determined to be
6024 VARYING, which causes i_5 to drop down to VARYING. So, another
6025 visit to i_14 is scheduled. In this second visit, we compute the
6026 exact same range and equivalence set for i_14, namely ~[0, 0] and
6027 { i_5 }. But we did not have the previous range for i_5
6028 registered, so vrp_visit_assignment thinks that the range for
6029 i_14 has not changed. Therefore, the predicate 'if (i_14 == 1)'
6030 is not visited again, which stops propagation from visiting
6031 statements in the THEN clause of that if().
6033 To properly fix this we would need to keep the previous range
6034 value for the names in the equivalence set. This way we would've
6035 discovered that from one visit to the other i_5 changed from
6036 range [8, 8] to VR_VARYING.
6038 However, fixing this apparent limitation may not be worth the
6039 additional checking. Testing on several code bases (GCC, DLV,
6040 MICO, TRAMP3D and SPEC2000) showed that doing this results in
6041 4 more predicates folded in SPEC. */
6044 val
= vrp_evaluate_conditional_warnv_with_ops (gimple_cond_code (stmt
),
6045 gimple_cond_lhs (stmt
),
6046 gimple_cond_rhs (stmt
),
6051 *taken_edge_p
= find_taken_edge (gimple_bb (stmt
), val
);
6054 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
6056 "\nIgnoring predicate evaluation because "
6057 "it assumes that signed overflow is undefined");
6062 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
6064 fprintf (dump_file
, "\nPredicate evaluates to: ");
6065 if (val
== NULL_TREE
)
6066 fprintf (dump_file
, "DON'T KNOW\n");
6068 print_generic_stmt (dump_file
, val
, 0);
6071 return (*taken_edge_p
) ? SSA_PROP_INTERESTING
: SSA_PROP_VARYING
;
6074 /* Searches the case label vector VEC for the index *IDX of the CASE_LABEL
6075 that includes the value VAL. The search is restricted to the range
6076 [START_IDX, n - 1] where n is the size of VEC.
6078 If there is a CASE_LABEL for VAL, its index is placed in IDX and true is
6081 If there is no CASE_LABEL for VAL and there is one that is larger than VAL,
6082 it is placed in IDX and false is returned.
6084 If VAL is larger than any CASE_LABEL, n is placed on IDX and false is
6088 find_case_label_index (gimple stmt
, size_t start_idx
, tree val
, size_t *idx
)
6090 size_t n
= gimple_switch_num_labels (stmt
);
6093 /* Find case label for minimum of the value range or the next one.
6094 At each iteration we are searching in [low, high - 1]. */
6096 for (low
= start_idx
, high
= n
; high
!= low
; )
6100 /* Note that i != high, so we never ask for n. */
6101 size_t i
= (high
+ low
) / 2;
6102 t
= gimple_switch_label (stmt
, i
);
6104 /* Cache the result of comparing CASE_LOW and val. */
6105 cmp
= tree_int_cst_compare (CASE_LOW (t
), val
);
6109 /* Ranges cannot be empty. */
6118 if (CASE_HIGH (t
) != NULL
6119 && tree_int_cst_compare (CASE_HIGH (t
), val
) >= 0)
6131 /* Searches the case label vector VEC for the range of CASE_LABELs that is used
6132 for values between MIN and MAX. The first index is placed in MIN_IDX. The
6133 last index is placed in MAX_IDX. If the range of CASE_LABELs is empty
6134 then MAX_IDX < MIN_IDX.
6135 Returns true if the default label is not needed. */
6138 find_case_label_range (gimple stmt
, tree min
, tree max
, size_t *min_idx
,
6142 bool min_take_default
= !find_case_label_index (stmt
, 1, min
, &i
);
6143 bool max_take_default
= !find_case_label_index (stmt
, i
, max
, &j
);
6147 && max_take_default
)
6149 /* Only the default case label reached.
6150 Return an empty range. */
6157 bool take_default
= min_take_default
|| max_take_default
;
6161 if (max_take_default
)
6164 /* If the case label range is continuous, we do not need
6165 the default case label. Verify that. */
6166 high
= CASE_LOW (gimple_switch_label (stmt
, i
));
6167 if (CASE_HIGH (gimple_switch_label (stmt
, i
)))
6168 high
= CASE_HIGH (gimple_switch_label (stmt
, i
));
6169 for (k
= i
+ 1; k
<= j
; ++k
)
6171 low
= CASE_LOW (gimple_switch_label (stmt
, k
));
6172 if (!integer_onep (int_const_binop (MINUS_EXPR
, low
, high
, 0)))
6174 take_default
= true;
6178 if (CASE_HIGH (gimple_switch_label (stmt
, k
)))
6179 high
= CASE_HIGH (gimple_switch_label (stmt
, k
));
6184 return !take_default
;
6188 /* Visit switch statement STMT. If we can determine which edge
6189 will be taken out of STMT's basic block, record it in
6190 *TAKEN_EDGE_P and return SSA_PROP_INTERESTING. Otherwise, return
6191 SSA_PROP_VARYING. */
6193 static enum ssa_prop_result
6194 vrp_visit_switch_stmt (gimple stmt
, edge
*taken_edge_p
)
6198 size_t i
= 0, j
= 0;
6201 *taken_edge_p
= NULL
;
6202 op
= gimple_switch_index (stmt
);
6203 if (TREE_CODE (op
) != SSA_NAME
)
6204 return SSA_PROP_VARYING
;
6206 vr
= get_value_range (op
);
6207 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
6209 fprintf (dump_file
, "\nVisiting switch expression with operand ");
6210 print_generic_expr (dump_file
, op
, 0);
6211 fprintf (dump_file
, " with known range ");
6212 dump_value_range (dump_file
, vr
);
6213 fprintf (dump_file
, "\n");
6216 if (vr
->type
!= VR_RANGE
6217 || symbolic_range_p (vr
))
6218 return SSA_PROP_VARYING
;
6220 /* Find the single edge that is taken from the switch expression. */
6221 take_default
= !find_case_label_range (stmt
, vr
->min
, vr
->max
, &i
, &j
);
6223 /* Check if the range spans no CASE_LABEL. If so, we only reach the default
6227 gcc_assert (take_default
);
6228 val
= gimple_switch_default_label (stmt
);
6232 /* Check if labels with index i to j and maybe the default label
6233 are all reaching the same label. */
6235 val
= gimple_switch_label (stmt
, i
);
6237 && CASE_LABEL (gimple_switch_default_label (stmt
))
6238 != CASE_LABEL (val
))
6240 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
6241 fprintf (dump_file
, " not a single destination for this "
6243 return SSA_PROP_VARYING
;
6245 for (++i
; i
<= j
; ++i
)
6247 if (CASE_LABEL (gimple_switch_label (stmt
, i
)) != CASE_LABEL (val
))
6249 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
6250 fprintf (dump_file
, " not a single destination for this "
6252 return SSA_PROP_VARYING
;
6257 *taken_edge_p
= find_edge (gimple_bb (stmt
),
6258 label_to_block (CASE_LABEL (val
)));
6260 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
6262 fprintf (dump_file
, " will take edge to ");
6263 print_generic_stmt (dump_file
, CASE_LABEL (val
), 0);
6266 return SSA_PROP_INTERESTING
;
6270 /* Evaluate statement STMT. If the statement produces a useful range,
6271 return SSA_PROP_INTERESTING and record the SSA name with the
6272 interesting range into *OUTPUT_P.
6274 If STMT is a conditional branch and we can determine its truth
6275 value, the taken edge is recorded in *TAKEN_EDGE_P.
6277 If STMT produces a varying value, return SSA_PROP_VARYING. */
6279 static enum ssa_prop_result
6280 vrp_visit_stmt (gimple stmt
, edge
*taken_edge_p
, tree
*output_p
)
6285 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
6287 fprintf (dump_file
, "\nVisiting statement:\n");
6288 print_gimple_stmt (dump_file
, stmt
, 0, dump_flags
);
6289 fprintf (dump_file
, "\n");
6292 if (!stmt_interesting_for_vrp (stmt
))
6293 gcc_assert (stmt_ends_bb_p (stmt
));
6294 else if (is_gimple_assign (stmt
) || is_gimple_call (stmt
))
6296 /* In general, assignments with virtual operands are not useful
6297 for deriving ranges, with the obvious exception of calls to
6298 builtin functions. */
6300 if ((is_gimple_call (stmt
)
6301 && gimple_call_fndecl (stmt
) != NULL_TREE
6302 && DECL_IS_BUILTIN (gimple_call_fndecl (stmt
)))
6303 || !gimple_vuse (stmt
))
6304 return vrp_visit_assignment_or_call (stmt
, output_p
);
6306 else if (gimple_code (stmt
) == GIMPLE_COND
)
6307 return vrp_visit_cond_stmt (stmt
, taken_edge_p
);
6308 else if (gimple_code (stmt
) == GIMPLE_SWITCH
)
6309 return vrp_visit_switch_stmt (stmt
, taken_edge_p
);
6311 /* All other statements produce nothing of interest for VRP, so mark
6312 their outputs varying and prevent further simulation. */
6313 FOR_EACH_SSA_TREE_OPERAND (def
, stmt
, iter
, SSA_OP_DEF
)
6314 set_value_range_to_varying (get_value_range (def
));
6316 return SSA_PROP_VARYING
;
6320 /* Meet operation for value ranges. Given two value ranges VR0 and
6321 VR1, store in VR0 a range that contains both VR0 and VR1. This
6322 may not be the smallest possible such range. */
6325 vrp_meet (value_range_t
*vr0
, value_range_t
*vr1
)
6327 if (vr0
->type
== VR_UNDEFINED
)
6329 copy_value_range (vr0
, vr1
);
6333 if (vr1
->type
== VR_UNDEFINED
)
6335 /* Nothing to do. VR0 already has the resulting range. */
6339 if (vr0
->type
== VR_VARYING
)
6341 /* Nothing to do. VR0 already has the resulting range. */
6345 if (vr1
->type
== VR_VARYING
)
6347 set_value_range_to_varying (vr0
);
6351 if (vr0
->type
== VR_RANGE
&& vr1
->type
== VR_RANGE
)
6356 /* Compute the convex hull of the ranges. The lower limit of
6357 the new range is the minimum of the two ranges. If they
6358 cannot be compared, then give up. */
6359 cmp
= compare_values (vr0
->min
, vr1
->min
);
6360 if (cmp
== 0 || cmp
== 1)
6367 /* Similarly, the upper limit of the new range is the maximum
6368 of the two ranges. If they cannot be compared, then
6370 cmp
= compare_values (vr0
->max
, vr1
->max
);
6371 if (cmp
== 0 || cmp
== -1)
6378 /* Check for useless ranges. */
6379 if (INTEGRAL_TYPE_P (TREE_TYPE (min
))
6380 && ((vrp_val_is_min (min
) || is_overflow_infinity (min
))
6381 && (vrp_val_is_max (max
) || is_overflow_infinity (max
))))
6384 /* The resulting set of equivalences is the intersection of
6386 if (vr0
->equiv
&& vr1
->equiv
&& vr0
->equiv
!= vr1
->equiv
)
6387 bitmap_and_into (vr0
->equiv
, vr1
->equiv
);
6388 else if (vr0
->equiv
&& !vr1
->equiv
)
6389 bitmap_clear (vr0
->equiv
);
6391 set_value_range (vr0
, vr0
->type
, min
, max
, vr0
->equiv
);
6393 else if (vr0
->type
== VR_ANTI_RANGE
&& vr1
->type
== VR_ANTI_RANGE
)
6395 /* Two anti-ranges meet only if their complements intersect.
6396 Only handle the case of identical ranges. */
6397 if (compare_values (vr0
->min
, vr1
->min
) == 0
6398 && compare_values (vr0
->max
, vr1
->max
) == 0
6399 && compare_values (vr0
->min
, vr0
->max
) == 0)
6401 /* The resulting set of equivalences is the intersection of
6403 if (vr0
->equiv
&& vr1
->equiv
&& vr0
->equiv
!= vr1
->equiv
)
6404 bitmap_and_into (vr0
->equiv
, vr1
->equiv
);
6405 else if (vr0
->equiv
&& !vr1
->equiv
)
6406 bitmap_clear (vr0
->equiv
);
6411 else if (vr0
->type
== VR_ANTI_RANGE
|| vr1
->type
== VR_ANTI_RANGE
)
6413 /* For a numeric range [VAL1, VAL2] and an anti-range ~[VAL3, VAL4],
6414 only handle the case where the ranges have an empty intersection.
6415 The result of the meet operation is the anti-range. */
6416 if (!symbolic_range_p (vr0
)
6417 && !symbolic_range_p (vr1
)
6418 && !value_ranges_intersect_p (vr0
, vr1
))
6420 /* Copy most of VR1 into VR0. Don't copy VR1's equivalence
6421 set. We need to compute the intersection of the two
6422 equivalence sets. */
6423 if (vr1
->type
== VR_ANTI_RANGE
)
6424 set_value_range (vr0
, vr1
->type
, vr1
->min
, vr1
->max
, vr0
->equiv
);
6426 /* The resulting set of equivalences is the intersection of
6428 if (vr0
->equiv
&& vr1
->equiv
&& vr0
->equiv
!= vr1
->equiv
)
6429 bitmap_and_into (vr0
->equiv
, vr1
->equiv
);
6430 else if (vr0
->equiv
&& !vr1
->equiv
)
6431 bitmap_clear (vr0
->equiv
);
6442 /* Failed to find an efficient meet. Before giving up and setting
6443 the result to VARYING, see if we can at least derive a useful
6444 anti-range. FIXME, all this nonsense about distinguishing
6445 anti-ranges from ranges is necessary because of the odd
6446 semantics of range_includes_zero_p and friends. */
6447 if (!symbolic_range_p (vr0
)
6448 && ((vr0
->type
== VR_RANGE
&& !range_includes_zero_p (vr0
))
6449 || (vr0
->type
== VR_ANTI_RANGE
&& range_includes_zero_p (vr0
)))
6450 && !symbolic_range_p (vr1
)
6451 && ((vr1
->type
== VR_RANGE
&& !range_includes_zero_p (vr1
))
6452 || (vr1
->type
== VR_ANTI_RANGE
&& range_includes_zero_p (vr1
))))
6454 set_value_range_to_nonnull (vr0
, TREE_TYPE (vr0
->min
));
6456 /* Since this meet operation did not result from the meeting of
6457 two equivalent names, VR0 cannot have any equivalences. */
6459 bitmap_clear (vr0
->equiv
);
6462 set_value_range_to_varying (vr0
);
6466 /* Visit all arguments for PHI node PHI that flow through executable
6467 edges. If a valid value range can be derived from all the incoming
6468 value ranges, set a new range for the LHS of PHI. */
6470 static enum ssa_prop_result
6471 vrp_visit_phi_node (gimple phi
)
6474 tree lhs
= PHI_RESULT (phi
);
6475 value_range_t
*lhs_vr
= get_value_range (lhs
);
6476 value_range_t vr_result
= { VR_UNDEFINED
, NULL_TREE
, NULL_TREE
, NULL
};
6477 int edges
, old_edges
;
6480 copy_value_range (&vr_result
, lhs_vr
);
6482 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
6484 fprintf (dump_file
, "\nVisiting PHI node: ");
6485 print_gimple_stmt (dump_file
, phi
, 0, dump_flags
);
6489 for (i
= 0; i
< gimple_phi_num_args (phi
); i
++)
6491 edge e
= gimple_phi_arg_edge (phi
, i
);
6493 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
6496 "\n Argument #%d (%d -> %d %sexecutable)\n",
6497 (int) i
, e
->src
->index
, e
->dest
->index
,
6498 (e
->flags
& EDGE_EXECUTABLE
) ? "" : "not ");
6501 if (e
->flags
& EDGE_EXECUTABLE
)
6503 tree arg
= PHI_ARG_DEF (phi
, i
);
6504 value_range_t vr_arg
;
6508 if (TREE_CODE (arg
) == SSA_NAME
)
6510 vr_arg
= *(get_value_range (arg
));
6514 if (is_overflow_infinity (arg
))
6516 arg
= copy_node (arg
);
6517 TREE_OVERFLOW (arg
) = 0;
6520 vr_arg
.type
= VR_RANGE
;
6523 vr_arg
.equiv
= NULL
;
6526 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
6528 fprintf (dump_file
, "\t");
6529 print_generic_expr (dump_file
, arg
, dump_flags
);
6530 fprintf (dump_file
, "\n\tValue: ");
6531 dump_value_range (dump_file
, &vr_arg
);
6532 fprintf (dump_file
, "\n");
6535 vrp_meet (&vr_result
, &vr_arg
);
6537 if (vr_result
.type
== VR_VARYING
)
6542 /* If this is a loop PHI node SCEV may known more about its
6545 && (l
= loop_containing_stmt (phi
))
6546 && l
->header
== gimple_bb (phi
))
6547 adjust_range_with_scev (&vr_result
, l
, phi
, lhs
);
6549 if (vr_result
.type
== VR_VARYING
)
6552 old_edges
= vr_phi_edge_counts
[SSA_NAME_VERSION (lhs
)];
6553 vr_phi_edge_counts
[SSA_NAME_VERSION (lhs
)] = edges
;
6555 /* To prevent infinite iterations in the algorithm, derive ranges
6556 when the new value is slightly bigger or smaller than the
6557 previous one. We don't do this if we have seen a new executable
6558 edge; this helps us avoid an overflow infinity for conditionals
6559 which are not in a loop. */
6560 if (lhs_vr
->type
== VR_RANGE
&& vr_result
.type
== VR_RANGE
6561 && edges
<= old_edges
)
6563 if (!POINTER_TYPE_P (TREE_TYPE (lhs
)))
6565 int cmp_min
= compare_values (lhs_vr
->min
, vr_result
.min
);
6566 int cmp_max
= compare_values (lhs_vr
->max
, vr_result
.max
);
6568 /* If the new minimum is smaller or larger than the previous
6569 one, go all the way to -INF. In the first case, to avoid
6570 iterating millions of times to reach -INF, and in the
6571 other case to avoid infinite bouncing between different
6573 if (cmp_min
> 0 || cmp_min
< 0)
6575 /* If we will end up with a (-INF, +INF) range, set it to
6576 VARYING. Same if the previous max value was invalid for
6577 the type and we'd end up with vr_result.min > vr_result.max. */
6578 if (vrp_val_is_max (vr_result
.max
)
6579 || compare_values (TYPE_MIN_VALUE (TREE_TYPE (vr_result
.min
)),
6583 if (!needs_overflow_infinity (TREE_TYPE (vr_result
.min
))
6584 || !vrp_var_may_overflow (lhs
, phi
))
6585 vr_result
.min
= TYPE_MIN_VALUE (TREE_TYPE (vr_result
.min
));
6586 else if (supports_overflow_infinity (TREE_TYPE (vr_result
.min
)))
6588 negative_overflow_infinity (TREE_TYPE (vr_result
.min
));
6593 /* Similarly, if the new maximum is smaller or larger than
6594 the previous one, go all the way to +INF. */
6595 if (cmp_max
< 0 || cmp_max
> 0)
6597 /* If we will end up with a (-INF, +INF) range, set it to
6598 VARYING. Same if the previous min value was invalid for
6599 the type and we'd end up with vr_result.max < vr_result.min. */
6600 if (vrp_val_is_min (vr_result
.min
)
6601 || compare_values (TYPE_MAX_VALUE (TREE_TYPE (vr_result
.max
)),
6605 if (!needs_overflow_infinity (TREE_TYPE (vr_result
.max
))
6606 || !vrp_var_may_overflow (lhs
, phi
))
6607 vr_result
.max
= TYPE_MAX_VALUE (TREE_TYPE (vr_result
.max
));
6608 else if (supports_overflow_infinity (TREE_TYPE (vr_result
.max
)))
6610 positive_overflow_infinity (TREE_TYPE (vr_result
.max
));
6617 /* If the new range is different than the previous value, keep
6619 if (update_value_range (lhs
, &vr_result
))
6621 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
6623 fprintf (dump_file
, "Found new range for ");
6624 print_generic_expr (dump_file
, lhs
, 0);
6625 fprintf (dump_file
, ": ");
6626 dump_value_range (dump_file
, &vr_result
);
6627 fprintf (dump_file
, "\n\n");
6630 return SSA_PROP_INTERESTING
;
6633 /* Nothing changed, don't add outgoing edges. */
6634 return SSA_PROP_NOT_INTERESTING
;
6636 /* No match found. Set the LHS to VARYING. */
6638 set_value_range_to_varying (lhs_vr
);
6639 return SSA_PROP_VARYING
;
6642 /* Simplify boolean operations if the source is known
6643 to be already a boolean. */
6645 simplify_truth_ops_using_ranges (gimple_stmt_iterator
*gsi
, gimple stmt
)
6647 enum tree_code rhs_code
= gimple_assign_rhs_code (stmt
);
6652 bool need_conversion
;
6654 op0
= gimple_assign_rhs1 (stmt
);
6655 if (TYPE_PRECISION (TREE_TYPE (op0
)) != 1)
6657 if (TREE_CODE (op0
) != SSA_NAME
)
6659 vr
= get_value_range (op0
);
6661 val
= compare_range_with_value (GE_EXPR
, vr
, integer_zero_node
, &sop
);
6662 if (!val
|| !integer_onep (val
))
6665 val
= compare_range_with_value (LE_EXPR
, vr
, integer_one_node
, &sop
);
6666 if (!val
|| !integer_onep (val
))
6670 if (rhs_code
== TRUTH_NOT_EXPR
)
6673 op1
= build_int_cst (TREE_TYPE (op0
), 1);
6677 op1
= gimple_assign_rhs2 (stmt
);
6679 /* Reduce number of cases to handle. */
6680 if (is_gimple_min_invariant (op1
))
6682 /* Exclude anything that should have been already folded. */
6683 if (rhs_code
!= EQ_EXPR
6684 && rhs_code
!= NE_EXPR
6685 && rhs_code
!= TRUTH_XOR_EXPR
)
6688 if (!integer_zerop (op1
)
6689 && !integer_onep (op1
)
6690 && !integer_all_onesp (op1
))
6693 /* Limit the number of cases we have to consider. */
6694 if (rhs_code
== EQ_EXPR
)
6697 op1
= fold_unary (TRUTH_NOT_EXPR
, TREE_TYPE (op1
), op1
);
6702 /* Punt on A == B as there is no BIT_XNOR_EXPR. */
6703 if (rhs_code
== EQ_EXPR
)
6706 if (TYPE_PRECISION (TREE_TYPE (op1
)) != 1)
6708 vr
= get_value_range (op1
);
6709 val
= compare_range_with_value (GE_EXPR
, vr
, integer_zero_node
, &sop
);
6710 if (!val
|| !integer_onep (val
))
6713 val
= compare_range_with_value (LE_EXPR
, vr
, integer_one_node
, &sop
);
6714 if (!val
|| !integer_onep (val
))
6720 if (sop
&& issue_strict_overflow_warning (WARN_STRICT_OVERFLOW_MISC
))
6722 location_t location
;
6724 if (!gimple_has_location (stmt
))
6725 location
= input_location
;
6727 location
= gimple_location (stmt
);
6729 if (rhs_code
== TRUTH_AND_EXPR
|| rhs_code
== TRUTH_OR_EXPR
)
6730 warning_at (location
, OPT_Wstrict_overflow
,
6731 _("assuming signed overflow does not occur when "
6732 "simplifying && or || to & or |"));
6734 warning_at (location
, OPT_Wstrict_overflow
,
6735 _("assuming signed overflow does not occur when "
6736 "simplifying ==, != or ! to identity or ^"));
6740 !useless_type_conversion_p (TREE_TYPE (gimple_assign_lhs (stmt
)),
6743 /* Make sure to not sign-extend -1 as a boolean value. */
6745 && !TYPE_UNSIGNED (TREE_TYPE (op0
))
6746 && TYPE_PRECISION (TREE_TYPE (op0
)) == 1)
6751 case TRUTH_AND_EXPR
:
6752 rhs_code
= BIT_AND_EXPR
;
6755 rhs_code
= BIT_IOR_EXPR
;
6757 case TRUTH_XOR_EXPR
:
6759 if (integer_zerop (op1
))
6761 gimple_assign_set_rhs_with_ops (gsi
,
6762 need_conversion
? NOP_EXPR
: SSA_NAME
,
6764 update_stmt (gsi_stmt (*gsi
));
6768 rhs_code
= BIT_XOR_EXPR
;
6774 if (need_conversion
)
6777 gimple_assign_set_rhs_with_ops (gsi
, rhs_code
, op0
, op1
);
6778 update_stmt (gsi_stmt (*gsi
));
6782 /* Simplify a division or modulo operator to a right shift or
6783 bitwise and if the first operand is unsigned or is greater
6784 than zero and the second operand is an exact power of two. */
6787 simplify_div_or_mod_using_ranges (gimple stmt
)
6789 enum tree_code rhs_code
= gimple_assign_rhs_code (stmt
);
6791 tree op0
= gimple_assign_rhs1 (stmt
);
6792 tree op1
= gimple_assign_rhs2 (stmt
);
6793 value_range_t
*vr
= get_value_range (gimple_assign_rhs1 (stmt
));
6795 if (TYPE_UNSIGNED (TREE_TYPE (op0
)))
6797 val
= integer_one_node
;
6803 val
= compare_range_with_value (GE_EXPR
, vr
, integer_zero_node
, &sop
);
6807 && integer_onep (val
)
6808 && issue_strict_overflow_warning (WARN_STRICT_OVERFLOW_MISC
))
6810 location_t location
;
6812 if (!gimple_has_location (stmt
))
6813 location
= input_location
;
6815 location
= gimple_location (stmt
);
6816 warning_at (location
, OPT_Wstrict_overflow
,
6817 "assuming signed overflow does not occur when "
6818 "simplifying %</%> or %<%%%> to %<>>%> or %<&%>");
6822 if (val
&& integer_onep (val
))
6826 if (rhs_code
== TRUNC_DIV_EXPR
)
6828 t
= build_int_cst (NULL_TREE
, tree_log2 (op1
));
6829 gimple_assign_set_rhs_code (stmt
, RSHIFT_EXPR
);
6830 gimple_assign_set_rhs1 (stmt
, op0
);
6831 gimple_assign_set_rhs2 (stmt
, t
);
6835 t
= build_int_cst (TREE_TYPE (op1
), 1);
6836 t
= int_const_binop (MINUS_EXPR
, op1
, t
, 0);
6837 t
= fold_convert (TREE_TYPE (op0
), t
);
6839 gimple_assign_set_rhs_code (stmt
, BIT_AND_EXPR
);
6840 gimple_assign_set_rhs1 (stmt
, op0
);
6841 gimple_assign_set_rhs2 (stmt
, t
);
6851 /* If the operand to an ABS_EXPR is >= 0, then eliminate the
6852 ABS_EXPR. If the operand is <= 0, then simplify the
6853 ABS_EXPR into a NEGATE_EXPR. */
6856 simplify_abs_using_ranges (gimple stmt
)
6859 tree op
= gimple_assign_rhs1 (stmt
);
6860 tree type
= TREE_TYPE (op
);
6861 value_range_t
*vr
= get_value_range (op
);
6863 if (TYPE_UNSIGNED (type
))
6865 val
= integer_zero_node
;
6871 val
= compare_range_with_value (LE_EXPR
, vr
, integer_zero_node
, &sop
);
6875 val
= compare_range_with_value (GE_EXPR
, vr
, integer_zero_node
,
6880 if (integer_zerop (val
))
6881 val
= integer_one_node
;
6882 else if (integer_onep (val
))
6883 val
= integer_zero_node
;
6888 && (integer_onep (val
) || integer_zerop (val
)))
6890 if (sop
&& issue_strict_overflow_warning (WARN_STRICT_OVERFLOW_MISC
))
6892 location_t location
;
6894 if (!gimple_has_location (stmt
))
6895 location
= input_location
;
6897 location
= gimple_location (stmt
);
6898 warning_at (location
, OPT_Wstrict_overflow
,
6899 "assuming signed overflow does not occur when "
6900 "simplifying %<abs (X)%> to %<X%> or %<-X%>");
6903 gimple_assign_set_rhs1 (stmt
, op
);
6904 if (integer_onep (val
))
6905 gimple_assign_set_rhs_code (stmt
, NEGATE_EXPR
);
6907 gimple_assign_set_rhs_code (stmt
, SSA_NAME
);
6916 /* Optimize away redundant BIT_AND_EXPR and BIT_IOR_EXPR.
6917 If all the bits that are being cleared by & are already
6918 known to be zero from VR, or all the bits that are being
6919 set by | are already known to be one from VR, the bit
6920 operation is redundant. */
6923 simplify_bit_ops_using_ranges (gimple_stmt_iterator
*gsi
, gimple stmt
)
6925 tree op0
= gimple_assign_rhs1 (stmt
);
6926 tree op1
= gimple_assign_rhs2 (stmt
);
6927 tree op
= NULL_TREE
;
6928 value_range_t vr0
= { VR_UNDEFINED
, NULL_TREE
, NULL_TREE
, NULL
};
6929 value_range_t vr1
= { VR_UNDEFINED
, NULL_TREE
, NULL_TREE
, NULL
};
6930 double_int may_be_nonzero0
, may_be_nonzero1
;
6931 double_int must_be_nonzero0
, must_be_nonzero1
;
6934 if (TREE_CODE (op0
) == SSA_NAME
)
6935 vr0
= *(get_value_range (op0
));
6936 else if (is_gimple_min_invariant (op0
))
6937 set_value_range_to_value (&vr0
, op0
, NULL
);
6941 if (TREE_CODE (op1
) == SSA_NAME
)
6942 vr1
= *(get_value_range (op1
));
6943 else if (is_gimple_min_invariant (op1
))
6944 set_value_range_to_value (&vr1
, op1
, NULL
);
6948 if (!zero_nonzero_bits_from_vr (&vr0
, &may_be_nonzero0
, &must_be_nonzero0
))
6950 if (!zero_nonzero_bits_from_vr (&vr1
, &may_be_nonzero1
, &must_be_nonzero1
))
6953 switch (gimple_assign_rhs_code (stmt
))
6956 mask
= double_int_and (may_be_nonzero0
,
6957 double_int_not (must_be_nonzero1
));
6958 if (double_int_zero_p (mask
))
6963 mask
= double_int_and (may_be_nonzero1
,
6964 double_int_not (must_be_nonzero0
));
6965 if (double_int_zero_p (mask
))
6972 mask
= double_int_and (may_be_nonzero0
,
6973 double_int_not (must_be_nonzero1
));
6974 if (double_int_zero_p (mask
))
6979 mask
= double_int_and (may_be_nonzero1
,
6980 double_int_not (must_be_nonzero0
));
6981 if (double_int_zero_p (mask
))
6991 if (op
== NULL_TREE
)
6994 gimple_assign_set_rhs_with_ops (gsi
, TREE_CODE (op
), op
, NULL
);
6995 update_stmt (gsi_stmt (*gsi
));
6999 /* We are comparing trees OP0 and OP1 using COND_CODE. OP0 has
7000 a known value range VR.
7002 If there is one and only one value which will satisfy the
7003 conditional, then return that value. Else return NULL. */
7006 test_for_singularity (enum tree_code cond_code
, tree op0
,
7007 tree op1
, value_range_t
*vr
)
7012 /* Extract minimum/maximum values which satisfy the
7013 the conditional as it was written. */
7014 if (cond_code
== LE_EXPR
|| cond_code
== LT_EXPR
)
7016 /* This should not be negative infinity; there is no overflow
7018 min
= TYPE_MIN_VALUE (TREE_TYPE (op0
));
7021 if (cond_code
== LT_EXPR
&& !is_overflow_infinity (max
))
7023 tree one
= build_int_cst (TREE_TYPE (op0
), 1);
7024 max
= fold_build2 (MINUS_EXPR
, TREE_TYPE (op0
), max
, one
);
7026 TREE_NO_WARNING (max
) = 1;
7029 else if (cond_code
== GE_EXPR
|| cond_code
== GT_EXPR
)
7031 /* This should not be positive infinity; there is no overflow
7033 max
= TYPE_MAX_VALUE (TREE_TYPE (op0
));
7036 if (cond_code
== GT_EXPR
&& !is_overflow_infinity (min
))
7038 tree one
= build_int_cst (TREE_TYPE (op0
), 1);
7039 min
= fold_build2 (PLUS_EXPR
, TREE_TYPE (op0
), min
, one
);
7041 TREE_NO_WARNING (min
) = 1;
7045 /* Now refine the minimum and maximum values using any
7046 value range information we have for op0. */
7049 if (compare_values (vr
->min
, min
) == 1)
7051 if (compare_values (vr
->max
, max
) == -1)
7054 /* If the new min/max values have converged to a single value,
7055 then there is only one value which can satisfy the condition,
7056 return that value. */
7057 if (operand_equal_p (min
, max
, 0) && is_gimple_min_invariant (min
))
7063 /* Simplify a conditional using a relational operator to an equality
7064 test if the range information indicates only one value can satisfy
7065 the original conditional. */
7068 simplify_cond_using_ranges (gimple stmt
)
7070 tree op0
= gimple_cond_lhs (stmt
);
7071 tree op1
= gimple_cond_rhs (stmt
);
7072 enum tree_code cond_code
= gimple_cond_code (stmt
);
7074 if (cond_code
!= NE_EXPR
7075 && cond_code
!= EQ_EXPR
7076 && TREE_CODE (op0
) == SSA_NAME
7077 && INTEGRAL_TYPE_P (TREE_TYPE (op0
))
7078 && is_gimple_min_invariant (op1
))
7080 value_range_t
*vr
= get_value_range (op0
);
7082 /* If we have range information for OP0, then we might be
7083 able to simplify this conditional. */
7084 if (vr
->type
== VR_RANGE
)
7086 tree new_tree
= test_for_singularity (cond_code
, op0
, op1
, vr
);
7092 fprintf (dump_file
, "Simplified relational ");
7093 print_gimple_stmt (dump_file
, stmt
, 0, 0);
7094 fprintf (dump_file
, " into ");
7097 gimple_cond_set_code (stmt
, EQ_EXPR
);
7098 gimple_cond_set_lhs (stmt
, op0
);
7099 gimple_cond_set_rhs (stmt
, new_tree
);
7105 print_gimple_stmt (dump_file
, stmt
, 0, 0);
7106 fprintf (dump_file
, "\n");
7112 /* Try again after inverting the condition. We only deal
7113 with integral types here, so no need to worry about
7114 issues with inverting FP comparisons. */
7115 cond_code
= invert_tree_comparison (cond_code
, false);
7116 new_tree
= test_for_singularity (cond_code
, op0
, op1
, vr
);
7122 fprintf (dump_file
, "Simplified relational ");
7123 print_gimple_stmt (dump_file
, stmt
, 0, 0);
7124 fprintf (dump_file
, " into ");
7127 gimple_cond_set_code (stmt
, NE_EXPR
);
7128 gimple_cond_set_lhs (stmt
, op0
);
7129 gimple_cond_set_rhs (stmt
, new_tree
);
7135 print_gimple_stmt (dump_file
, stmt
, 0, 0);
7136 fprintf (dump_file
, "\n");
7147 /* Simplify a switch statement using the value range of the switch
7151 simplify_switch_using_ranges (gimple stmt
)
7153 tree op
= gimple_switch_index (stmt
);
7158 size_t i
= 0, j
= 0, n
, n2
;
7162 if (TREE_CODE (op
) == SSA_NAME
)
7164 vr
= get_value_range (op
);
7166 /* We can only handle integer ranges. */
7167 if (vr
->type
!= VR_RANGE
7168 || symbolic_range_p (vr
))
7171 /* Find case label for min/max of the value range. */
7172 take_default
= !find_case_label_range (stmt
, vr
->min
, vr
->max
, &i
, &j
);
7174 else if (TREE_CODE (op
) == INTEGER_CST
)
7176 take_default
= !find_case_label_index (stmt
, 1, op
, &i
);
7190 n
= gimple_switch_num_labels (stmt
);
7192 /* Bail out if this is just all edges taken. */
7198 /* Build a new vector of taken case labels. */
7199 vec2
= make_tree_vec (j
- i
+ 1 + (int)take_default
);
7202 /* Add the default edge, if necessary. */
7204 TREE_VEC_ELT (vec2
, n2
++) = gimple_switch_default_label (stmt
);
7206 for (; i
<= j
; ++i
, ++n2
)
7207 TREE_VEC_ELT (vec2
, n2
) = gimple_switch_label (stmt
, i
);
7209 /* Mark needed edges. */
7210 for (i
= 0; i
< n2
; ++i
)
7212 e
= find_edge (gimple_bb (stmt
),
7213 label_to_block (CASE_LABEL (TREE_VEC_ELT (vec2
, i
))));
7214 e
->aux
= (void *)-1;
7217 /* Queue not needed edges for later removal. */
7218 FOR_EACH_EDGE (e
, ei
, gimple_bb (stmt
)->succs
)
7220 if (e
->aux
== (void *)-1)
7226 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
7228 fprintf (dump_file
, "removing unreachable case label\n");
7230 VEC_safe_push (edge
, heap
, to_remove_edges
, e
);
7231 e
->flags
&= ~EDGE_EXECUTABLE
;
7234 /* And queue an update for the stmt. */
7237 VEC_safe_push (switch_update
, heap
, to_update_switch_stmts
, &su
);
7241 /* Simplify STMT using ranges if possible. */
7244 simplify_stmt_using_ranges (gimple_stmt_iterator
*gsi
)
7246 gimple stmt
= gsi_stmt (*gsi
);
7247 if (is_gimple_assign (stmt
))
7249 enum tree_code rhs_code
= gimple_assign_rhs_code (stmt
);
7255 case TRUTH_NOT_EXPR
:
7256 case TRUTH_AND_EXPR
:
7258 case TRUTH_XOR_EXPR
:
7259 /* Transform EQ_EXPR, NE_EXPR, TRUTH_NOT_EXPR into BIT_XOR_EXPR
7260 or identity if the RHS is zero or one, and the LHS are known
7261 to be boolean values. Transform all TRUTH_*_EXPR into
7262 BIT_*_EXPR if both arguments are known to be boolean values. */
7263 if (INTEGRAL_TYPE_P (TREE_TYPE (gimple_assign_rhs1 (stmt
))))
7264 return simplify_truth_ops_using_ranges (gsi
, stmt
);
7267 /* Transform TRUNC_DIV_EXPR and TRUNC_MOD_EXPR into RSHIFT_EXPR
7268 and BIT_AND_EXPR respectively if the first operand is greater
7269 than zero and the second operand is an exact power of two. */
7270 case TRUNC_DIV_EXPR
:
7271 case TRUNC_MOD_EXPR
:
7272 if (INTEGRAL_TYPE_P (TREE_TYPE (gimple_assign_rhs1 (stmt
)))
7273 && integer_pow2p (gimple_assign_rhs2 (stmt
)))
7274 return simplify_div_or_mod_using_ranges (stmt
);
7277 /* Transform ABS (X) into X or -X as appropriate. */
7279 if (TREE_CODE (gimple_assign_rhs1 (stmt
)) == SSA_NAME
7280 && INTEGRAL_TYPE_P (TREE_TYPE (gimple_assign_rhs1 (stmt
))))
7281 return simplify_abs_using_ranges (stmt
);
7286 /* Optimize away BIT_AND_EXPR and BIT_IOR_EXPR
7287 if all the bits being cleared are already cleared or
7288 all the bits being set are already set. */
7289 if (INTEGRAL_TYPE_P (TREE_TYPE (gimple_assign_rhs1 (stmt
))))
7290 return simplify_bit_ops_using_ranges (gsi
, stmt
);
7297 else if (gimple_code (stmt
) == GIMPLE_COND
)
7298 return simplify_cond_using_ranges (stmt
);
7299 else if (gimple_code (stmt
) == GIMPLE_SWITCH
)
7300 return simplify_switch_using_ranges (stmt
);
7305 /* If the statement pointed by SI has a predicate whose value can be
7306 computed using the value range information computed by VRP, compute
7307 its value and return true. Otherwise, return false. */
7310 fold_predicate_in (gimple_stmt_iterator
*si
)
7312 bool assignment_p
= false;
7314 gimple stmt
= gsi_stmt (*si
);
7316 if (is_gimple_assign (stmt
)
7317 && TREE_CODE_CLASS (gimple_assign_rhs_code (stmt
)) == tcc_comparison
)
7319 assignment_p
= true;
7320 val
= vrp_evaluate_conditional (gimple_assign_rhs_code (stmt
),
7321 gimple_assign_rhs1 (stmt
),
7322 gimple_assign_rhs2 (stmt
),
7325 else if (gimple_code (stmt
) == GIMPLE_COND
)
7326 val
= vrp_evaluate_conditional (gimple_cond_code (stmt
),
7327 gimple_cond_lhs (stmt
),
7328 gimple_cond_rhs (stmt
),
7336 val
= fold_convert (gimple_expr_type (stmt
), val
);
7340 fprintf (dump_file
, "Folding predicate ");
7341 print_gimple_expr (dump_file
, stmt
, 0, 0);
7342 fprintf (dump_file
, " to ");
7343 print_generic_expr (dump_file
, val
, 0);
7344 fprintf (dump_file
, "\n");
7347 if (is_gimple_assign (stmt
))
7348 gimple_assign_set_rhs_from_tree (si
, val
);
7351 gcc_assert (gimple_code (stmt
) == GIMPLE_COND
);
7352 if (integer_zerop (val
))
7353 gimple_cond_make_false (stmt
);
7354 else if (integer_onep (val
))
7355 gimple_cond_make_true (stmt
);
7366 /* Callback for substitute_and_fold folding the stmt at *SI. */
7369 vrp_fold_stmt (gimple_stmt_iterator
*si
)
7371 if (fold_predicate_in (si
))
7374 return simplify_stmt_using_ranges (si
);
7377 /* Stack of dest,src equivalency pairs that need to be restored after
7378 each attempt to thread a block's incoming edge to an outgoing edge.
7380 A NULL entry is used to mark the end of pairs which need to be
7382 static VEC(tree
,heap
) *stack
;
7384 /* A trivial wrapper so that we can present the generic jump threading
7385 code with a simple API for simplifying statements. STMT is the
7386 statement we want to simplify, WITHIN_STMT provides the location
7387 for any overflow warnings. */
7390 simplify_stmt_for_jump_threading (gimple stmt
, gimple within_stmt
)
7392 /* We only use VRP information to simplify conditionals. This is
7393 overly conservative, but it's unclear if doing more would be
7394 worth the compile time cost. */
7395 if (gimple_code (stmt
) != GIMPLE_COND
)
7398 return vrp_evaluate_conditional (gimple_cond_code (stmt
),
7399 gimple_cond_lhs (stmt
),
7400 gimple_cond_rhs (stmt
), within_stmt
);
7403 /* Blocks which have more than one predecessor and more than
7404 one successor present jump threading opportunities, i.e.,
7405 when the block is reached from a specific predecessor, we
7406 may be able to determine which of the outgoing edges will
7407 be traversed. When this optimization applies, we are able
7408 to avoid conditionals at runtime and we may expose secondary
7409 optimization opportunities.
7411 This routine is effectively a driver for the generic jump
7412 threading code. It basically just presents the generic code
7413 with edges that may be suitable for jump threading.
7415 Unlike DOM, we do not iterate VRP if jump threading was successful.
7416 While iterating may expose new opportunities for VRP, it is expected
7417 those opportunities would be very limited and the compile time cost
7418 to expose those opportunities would be significant.
7420 As jump threading opportunities are discovered, they are registered
7421 for later realization. */
7424 identify_jump_threads (void)
7431 /* Ugh. When substituting values earlier in this pass we can
7432 wipe the dominance information. So rebuild the dominator
7433 information as we need it within the jump threading code. */
7434 calculate_dominance_info (CDI_DOMINATORS
);
7436 /* We do not allow VRP information to be used for jump threading
7437 across a back edge in the CFG. Otherwise it becomes too
7438 difficult to avoid eliminating loop exit tests. Of course
7439 EDGE_DFS_BACK is not accurate at this time so we have to
7441 mark_dfs_back_edges ();
7443 /* Do not thread across edges we are about to remove. Just marking
7444 them as EDGE_DFS_BACK will do. */
7445 for (i
= 0; VEC_iterate (edge
, to_remove_edges
, i
, e
); ++i
)
7446 e
->flags
|= EDGE_DFS_BACK
;
7448 /* Allocate our unwinder stack to unwind any temporary equivalences
7449 that might be recorded. */
7450 stack
= VEC_alloc (tree
, heap
, 20);
7452 /* To avoid lots of silly node creation, we create a single
7453 conditional and just modify it in-place when attempting to
7455 dummy
= gimple_build_cond (EQ_EXPR
,
7456 integer_zero_node
, integer_zero_node
,
7459 /* Walk through all the blocks finding those which present a
7460 potential jump threading opportunity. We could set this up
7461 as a dominator walker and record data during the walk, but
7462 I doubt it's worth the effort for the classes of jump
7463 threading opportunities we are trying to identify at this
7464 point in compilation. */
7469 /* If the generic jump threading code does not find this block
7470 interesting, then there is nothing to do. */
7471 if (! potentially_threadable_block (bb
))
7474 /* We only care about blocks ending in a COND_EXPR. While there
7475 may be some value in handling SWITCH_EXPR here, I doubt it's
7476 terribly important. */
7477 last
= gsi_stmt (gsi_last_bb (bb
));
7478 if (gimple_code (last
) != GIMPLE_COND
)
7481 /* We're basically looking for any kind of conditional with
7482 integral type arguments. */
7483 if (TREE_CODE (gimple_cond_lhs (last
)) == SSA_NAME
7484 && INTEGRAL_TYPE_P (TREE_TYPE (gimple_cond_lhs (last
)))
7485 && (TREE_CODE (gimple_cond_rhs (last
)) == SSA_NAME
7486 || is_gimple_min_invariant (gimple_cond_rhs (last
)))
7487 && INTEGRAL_TYPE_P (TREE_TYPE (gimple_cond_rhs (last
))))
7491 /* We've got a block with multiple predecessors and multiple
7492 successors which also ends in a suitable conditional. For
7493 each predecessor, see if we can thread it to a specific
7495 FOR_EACH_EDGE (e
, ei
, bb
->preds
)
7497 /* Do not thread across back edges or abnormal edges
7499 if (e
->flags
& (EDGE_DFS_BACK
| EDGE_COMPLEX
))
7502 thread_across_edge (dummy
, e
, true, &stack
,
7503 simplify_stmt_for_jump_threading
);
7508 /* We do not actually update the CFG or SSA graphs at this point as
7509 ASSERT_EXPRs are still in the IL and cfg cleanup code does not yet
7510 handle ASSERT_EXPRs gracefully. */
7513 /* We identified all the jump threading opportunities earlier, but could
7514 not transform the CFG at that time. This routine transforms the
7515 CFG and arranges for the dominator tree to be rebuilt if necessary.
7517 Note the SSA graph update will occur during the normal TODO
7518 processing by the pass manager. */
7520 finalize_jump_threads (void)
7522 thread_through_all_blocks (false);
7523 VEC_free (tree
, heap
, stack
);
7527 /* Traverse all the blocks folding conditionals with known ranges. */
7533 prop_value_t
*single_val_range
;
7534 bool do_value_subst_p
;
7535 unsigned num
= num_ssa_names
;
7539 fprintf (dump_file
, "\nValue ranges after VRP:\n\n");
7540 dump_all_value_ranges (dump_file
);
7541 fprintf (dump_file
, "\n");
7544 /* We may have ended with ranges that have exactly one value. Those
7545 values can be substituted as any other const propagated
7546 value using substitute_and_fold. */
7547 single_val_range
= XCNEWVEC (prop_value_t
, num
);
7549 do_value_subst_p
= false;
7550 for (i
= 0; i
< num
; i
++)
7552 && vr_value
[i
]->type
== VR_RANGE
7553 && vr_value
[i
]->min
== vr_value
[i
]->max
7554 && is_gimple_min_invariant (vr_value
[i
]->min
))
7556 single_val_range
[i
].value
= vr_value
[i
]->min
;
7557 do_value_subst_p
= true;
7560 if (!do_value_subst_p
)
7562 /* We found no single-valued ranges, don't waste time trying to
7563 do single value substitution in substitute_and_fold. */
7564 free (single_val_range
);
7565 single_val_range
= NULL
;
7568 substitute_and_fold (single_val_range
, vrp_fold_stmt
, false);
7570 if (warn_array_bounds
)
7571 check_all_array_refs ();
7573 /* We must identify jump threading opportunities before we release
7574 the datastructures built by VRP. */
7575 identify_jump_threads ();
7577 /* Free allocated memory. */
7578 for (i
= 0; i
< num
; i
++)
7581 BITMAP_FREE (vr_value
[i
]->equiv
);
7585 free (single_val_range
);
7587 free (vr_phi_edge_counts
);
7589 /* So that we can distinguish between VRP data being available
7590 and not available. */
7592 vr_phi_edge_counts
= NULL
;
7596 /* Main entry point to VRP (Value Range Propagation). This pass is
7597 loosely based on J. R. C. Patterson, ``Accurate Static Branch
7598 Prediction by Value Range Propagation,'' in SIGPLAN Conference on
7599 Programming Language Design and Implementation, pp. 67-78, 1995.
7600 Also available at http://citeseer.ist.psu.edu/patterson95accurate.html
7602 This is essentially an SSA-CCP pass modified to deal with ranges
7603 instead of constants.
7605 While propagating ranges, we may find that two or more SSA name
7606 have equivalent, though distinct ranges. For instance,
7609 2 p_4 = ASSERT_EXPR <p_3, p_3 != 0>
7611 4 p_5 = ASSERT_EXPR <p_4, p_4 == q_2>;
7615 In the code above, pointer p_5 has range [q_2, q_2], but from the
7616 code we can also determine that p_5 cannot be NULL and, if q_2 had
7617 a non-varying range, p_5's range should also be compatible with it.
7619 These equivalences are created by two expressions: ASSERT_EXPR and
7620 copy operations. Since p_5 is an assertion on p_4, and p_4 was the
7621 result of another assertion, then we can use the fact that p_5 and
7622 p_4 are equivalent when evaluating p_5's range.
7624 Together with value ranges, we also propagate these equivalences
7625 between names so that we can take advantage of information from
7626 multiple ranges when doing final replacement. Note that this
7627 equivalency relation is transitive but not symmetric.
7629 In the example above, p_5 is equivalent to p_4, q_2 and p_3, but we
7630 cannot assert that q_2 is equivalent to p_5 because q_2 may be used
7631 in contexts where that assertion does not hold (e.g., in line 6).
7633 TODO, the main difference between this pass and Patterson's is that
7634 we do not propagate edge probabilities. We only compute whether
7635 edges can be taken or not. That is, instead of having a spectrum
7636 of jump probabilities between 0 and 1, we only deal with 0, 1 and
7637 DON'T KNOW. In the future, it may be worthwhile to propagate
7638 probabilities to aid branch prediction. */
7647 loop_optimizer_init (LOOPS_NORMAL
| LOOPS_HAVE_RECORDED_EXITS
);
7648 rewrite_into_loop_closed_ssa (NULL
, TODO_update_ssa
);
7651 insert_range_assertions ();
7653 to_remove_edges
= VEC_alloc (edge
, heap
, 10);
7654 to_update_switch_stmts
= VEC_alloc (switch_update
, heap
, 5);
7655 threadedge_initialize_values ();
7658 ssa_propagate (vrp_visit_stmt
, vrp_visit_phi_node
);
7661 /* ASSERT_EXPRs must be removed before finalizing jump threads
7662 as finalizing jump threads calls the CFG cleanup code which
7663 does not properly handle ASSERT_EXPRs. */
7664 remove_range_assertions ();
7666 /* If we exposed any new variables, go ahead and put them into
7667 SSA form now, before we handle jump threading. This simplifies
7668 interactions between rewriting of _DECL nodes into SSA form
7669 and rewriting SSA_NAME nodes into SSA form after block
7670 duplication and CFG manipulation. */
7671 update_ssa (TODO_update_ssa
);
7673 finalize_jump_threads ();
7675 /* Remove dead edges from SWITCH_EXPR optimization. This leaves the
7676 CFG in a broken state and requires a cfg_cleanup run. */
7677 for (i
= 0; VEC_iterate (edge
, to_remove_edges
, i
, e
); ++i
)
7679 /* Update SWITCH_EXPR case label vector. */
7680 for (i
= 0; VEC_iterate (switch_update
, to_update_switch_stmts
, i
, su
); ++i
)
7683 size_t n
= TREE_VEC_LENGTH (su
->vec
);
7685 gimple_switch_set_num_labels (su
->stmt
, n
);
7686 for (j
= 0; j
< n
; j
++)
7687 gimple_switch_set_label (su
->stmt
, j
, TREE_VEC_ELT (su
->vec
, j
));
7688 /* As we may have replaced the default label with a regular one
7689 make sure to make it a real default label again. This ensures
7690 optimal expansion. */
7691 label
= gimple_switch_default_label (su
->stmt
);
7692 CASE_LOW (label
) = NULL_TREE
;
7693 CASE_HIGH (label
) = NULL_TREE
;
7696 if (VEC_length (edge
, to_remove_edges
) > 0)
7697 free_dominance_info (CDI_DOMINATORS
);
7699 VEC_free (edge
, heap
, to_remove_edges
);
7700 VEC_free (switch_update
, heap
, to_update_switch_stmts
);
7701 threadedge_finalize_values ();
7704 loop_optimizer_finalize ();
7711 return flag_tree_vrp
!= 0;
7714 struct gimple_opt_pass pass_vrp
=
7719 gate_vrp
, /* gate */
7720 execute_vrp
, /* execute */
7723 0, /* static_pass_number */
7724 TV_TREE_VRP
, /* tv_id */
7725 PROP_ssa
, /* properties_required */
7726 0, /* properties_provided */
7727 0, /* properties_destroyed */
7728 0, /* todo_flags_start */
7733 | TODO_update_ssa
/* todo_flags_finish */