1 /* Support routines for Value Range Propagation (VRP).
2 Copyright (C) 2005, 2006, 2007, 2008, 2009, 2010, 2011
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"
39 #include "tree-scalar-evolution.h"
40 #include "tree-ssa-propagate.h"
41 #include "tree-chrec.h"
42 #include "gimple-fold.h"
45 /* Type of value ranges. See value_range_d for a description of these
47 enum value_range_type
{ VR_UNDEFINED
, VR_RANGE
, VR_ANTI_RANGE
, VR_VARYING
};
49 /* Range of values that can be associated with an SSA_NAME after VRP
53 /* Lattice value represented by this range. */
54 enum value_range_type type
;
56 /* Minimum and maximum values represented by this range. These
57 values should be interpreted as follows:
59 - If TYPE is VR_UNDEFINED or VR_VARYING then MIN and MAX must
62 - If TYPE == VR_RANGE then MIN holds the minimum value and
63 MAX holds the maximum value of the range [MIN, MAX].
65 - If TYPE == ANTI_RANGE the variable is known to NOT
66 take any values in the range [MIN, MAX]. */
70 /* Set of SSA names whose value ranges are equivalent to this one.
71 This set is only valid when TYPE is VR_RANGE or VR_ANTI_RANGE. */
75 typedef struct value_range_d value_range_t
;
77 /* Set of SSA names found live during the RPO traversal of the function
78 for still active basic-blocks. */
81 /* Return true if the SSA name NAME is live on the edge E. */
84 live_on_edge (edge e
, tree name
)
86 return (live
[e
->dest
->index
]
87 && TEST_BIT (live
[e
->dest
->index
], SSA_NAME_VERSION (name
)));
90 /* Local functions. */
91 static int compare_values (tree val1
, tree val2
);
92 static int compare_values_warnv (tree val1
, tree val2
, bool *);
93 static void vrp_meet (value_range_t
*, value_range_t
*);
94 static tree
vrp_evaluate_conditional_warnv_with_ops (enum tree_code
,
95 tree
, tree
, bool, bool *,
98 /* Location information for ASSERT_EXPRs. Each instance of this
99 structure describes an ASSERT_EXPR for an SSA name. Since a single
100 SSA name may have more than one assertion associated with it, these
101 locations are kept in a linked list attached to the corresponding
103 struct assert_locus_d
105 /* Basic block where the assertion would be inserted. */
108 /* Some assertions need to be inserted on an edge (e.g., assertions
109 generated by COND_EXPRs). In those cases, BB will be NULL. */
112 /* Pointer to the statement that generated this assertion. */
113 gimple_stmt_iterator si
;
115 /* Predicate code for the ASSERT_EXPR. Must be COMPARISON_CLASS_P. */
116 enum tree_code comp_code
;
118 /* Value being compared against. */
121 /* Expression to compare. */
124 /* Next node in the linked list. */
125 struct assert_locus_d
*next
;
128 typedef struct assert_locus_d
*assert_locus_t
;
130 /* If bit I is present, it means that SSA name N_i has a list of
131 assertions that should be inserted in the IL. */
132 static bitmap need_assert_for
;
134 /* Array of locations lists where to insert assertions. ASSERTS_FOR[I]
135 holds a list of ASSERT_LOCUS_T nodes that describe where
136 ASSERT_EXPRs for SSA name N_I should be inserted. */
137 static assert_locus_t
*asserts_for
;
139 /* Value range array. After propagation, VR_VALUE[I] holds the range
140 of values that SSA name N_I may take. */
141 static value_range_t
**vr_value
;
143 /* For a PHI node which sets SSA name N_I, VR_COUNTS[I] holds the
144 number of executable edges we saw the last time we visited the
146 static int *vr_phi_edge_counts
;
153 static VEC (edge
, heap
) *to_remove_edges
;
154 DEF_VEC_O(switch_update
);
155 DEF_VEC_ALLOC_O(switch_update
, heap
);
156 static VEC (switch_update
, heap
) *to_update_switch_stmts
;
159 /* Return the maximum value for TYPE. */
162 vrp_val_max (const_tree type
)
164 if (!INTEGRAL_TYPE_P (type
))
167 return TYPE_MAX_VALUE (type
);
170 /* Return the minimum value for TYPE. */
173 vrp_val_min (const_tree type
)
175 if (!INTEGRAL_TYPE_P (type
))
178 return TYPE_MIN_VALUE (type
);
181 /* Return whether VAL is equal to the maximum value of its type. This
182 will be true for a positive overflow infinity. We can't do a
183 simple equality comparison with TYPE_MAX_VALUE because C typedefs
184 and Ada subtypes can produce types whose TYPE_MAX_VALUE is not ==
185 to the integer constant with the same value in the type. */
188 vrp_val_is_max (const_tree val
)
190 tree type_max
= vrp_val_max (TREE_TYPE (val
));
191 return (val
== type_max
192 || (type_max
!= NULL_TREE
193 && operand_equal_p (val
, type_max
, 0)));
196 /* Return whether VAL is equal to the minimum value of its type. This
197 will be true for a negative overflow infinity. */
200 vrp_val_is_min (const_tree val
)
202 tree type_min
= vrp_val_min (TREE_TYPE (val
));
203 return (val
== type_min
204 || (type_min
!= NULL_TREE
205 && operand_equal_p (val
, type_min
, 0)));
209 /* Return whether TYPE should use an overflow infinity distinct from
210 TYPE_{MIN,MAX}_VALUE. We use an overflow infinity value to
211 represent a signed overflow during VRP computations. An infinity
212 is distinct from a half-range, which will go from some number to
213 TYPE_{MIN,MAX}_VALUE. */
216 needs_overflow_infinity (const_tree type
)
218 return INTEGRAL_TYPE_P (type
) && !TYPE_OVERFLOW_WRAPS (type
);
221 /* Return whether TYPE can support our overflow infinity
222 representation: we use the TREE_OVERFLOW flag, which only exists
223 for constants. If TYPE doesn't support this, we don't optimize
224 cases which would require signed overflow--we drop them to
228 supports_overflow_infinity (const_tree type
)
230 tree min
= vrp_val_min (type
), max
= vrp_val_max (type
);
231 #ifdef ENABLE_CHECKING
232 gcc_assert (needs_overflow_infinity (type
));
234 return (min
!= NULL_TREE
235 && CONSTANT_CLASS_P (min
)
237 && CONSTANT_CLASS_P (max
));
240 /* VAL is the maximum or minimum value of a type. Return a
241 corresponding overflow infinity. */
244 make_overflow_infinity (tree val
)
246 gcc_checking_assert (val
!= NULL_TREE
&& CONSTANT_CLASS_P (val
));
247 val
= copy_node (val
);
248 TREE_OVERFLOW (val
) = 1;
252 /* Return a negative overflow infinity for TYPE. */
255 negative_overflow_infinity (tree type
)
257 gcc_checking_assert (supports_overflow_infinity (type
));
258 return make_overflow_infinity (vrp_val_min (type
));
261 /* Return a positive overflow infinity for TYPE. */
264 positive_overflow_infinity (tree type
)
266 gcc_checking_assert (supports_overflow_infinity (type
));
267 return make_overflow_infinity (vrp_val_max (type
));
270 /* Return whether VAL is a negative overflow infinity. */
273 is_negative_overflow_infinity (const_tree val
)
275 return (needs_overflow_infinity (TREE_TYPE (val
))
276 && CONSTANT_CLASS_P (val
)
277 && TREE_OVERFLOW (val
)
278 && vrp_val_is_min (val
));
281 /* Return whether VAL is a positive overflow infinity. */
284 is_positive_overflow_infinity (const_tree val
)
286 return (needs_overflow_infinity (TREE_TYPE (val
))
287 && CONSTANT_CLASS_P (val
)
288 && TREE_OVERFLOW (val
)
289 && vrp_val_is_max (val
));
292 /* Return whether VAL is a positive or negative overflow infinity. */
295 is_overflow_infinity (const_tree val
)
297 return (needs_overflow_infinity (TREE_TYPE (val
))
298 && CONSTANT_CLASS_P (val
)
299 && TREE_OVERFLOW (val
)
300 && (vrp_val_is_min (val
) || vrp_val_is_max (val
)));
303 /* Return whether STMT has a constant rhs that is_overflow_infinity. */
306 stmt_overflow_infinity (gimple stmt
)
308 if (is_gimple_assign (stmt
)
309 && get_gimple_rhs_class (gimple_assign_rhs_code (stmt
)) ==
311 return is_overflow_infinity (gimple_assign_rhs1 (stmt
));
315 /* If VAL is now an overflow infinity, return VAL. Otherwise, return
316 the same value with TREE_OVERFLOW clear. This can be used to avoid
317 confusing a regular value with an overflow value. */
320 avoid_overflow_infinity (tree val
)
322 if (!is_overflow_infinity (val
))
325 if (vrp_val_is_max (val
))
326 return vrp_val_max (TREE_TYPE (val
));
329 gcc_checking_assert (vrp_val_is_min (val
));
330 return vrp_val_min (TREE_TYPE (val
));
335 /* Return true if ARG is marked with the nonnull attribute in the
336 current function signature. */
339 nonnull_arg_p (const_tree arg
)
341 tree t
, attrs
, fntype
;
342 unsigned HOST_WIDE_INT arg_num
;
344 gcc_assert (TREE_CODE (arg
) == PARM_DECL
&& POINTER_TYPE_P (TREE_TYPE (arg
)));
346 /* The static chain decl is always non null. */
347 if (arg
== cfun
->static_chain_decl
)
350 fntype
= TREE_TYPE (current_function_decl
);
351 attrs
= lookup_attribute ("nonnull", TYPE_ATTRIBUTES (fntype
));
353 /* If "nonnull" wasn't specified, we know nothing about the argument. */
354 if (attrs
== NULL_TREE
)
357 /* If "nonnull" applies to all the arguments, then ARG is non-null. */
358 if (TREE_VALUE (attrs
) == NULL_TREE
)
361 /* Get the position number for ARG in the function signature. */
362 for (arg_num
= 1, t
= DECL_ARGUMENTS (current_function_decl
);
364 t
= DECL_CHAIN (t
), arg_num
++)
370 gcc_assert (t
== arg
);
372 /* Now see if ARG_NUM is mentioned in the nonnull list. */
373 for (t
= TREE_VALUE (attrs
); t
; t
= TREE_CHAIN (t
))
375 if (compare_tree_int (TREE_VALUE (t
), arg_num
) == 0)
383 /* Set value range VR to VR_VARYING. */
386 set_value_range_to_varying (value_range_t
*vr
)
388 vr
->type
= VR_VARYING
;
389 vr
->min
= vr
->max
= NULL_TREE
;
391 bitmap_clear (vr
->equiv
);
395 /* Set value range VR to {T, MIN, MAX, EQUIV}. */
398 set_value_range (value_range_t
*vr
, enum value_range_type t
, tree min
,
399 tree max
, bitmap equiv
)
401 #if defined ENABLE_CHECKING
402 /* Check the validity of the range. */
403 if (t
== VR_RANGE
|| t
== VR_ANTI_RANGE
)
407 gcc_assert (min
&& max
);
409 if (INTEGRAL_TYPE_P (TREE_TYPE (min
)) && t
== VR_ANTI_RANGE
)
410 gcc_assert (!vrp_val_is_min (min
) || !vrp_val_is_max (max
));
412 cmp
= compare_values (min
, max
);
413 gcc_assert (cmp
== 0 || cmp
== -1 || cmp
== -2);
415 if (needs_overflow_infinity (TREE_TYPE (min
)))
416 gcc_assert (!is_overflow_infinity (min
)
417 || !is_overflow_infinity (max
));
420 if (t
== VR_UNDEFINED
|| t
== VR_VARYING
)
421 gcc_assert (min
== NULL_TREE
&& max
== NULL_TREE
);
423 if (t
== VR_UNDEFINED
|| t
== VR_VARYING
)
424 gcc_assert (equiv
== NULL
|| bitmap_empty_p (equiv
));
431 /* Since updating the equivalence set involves deep copying the
432 bitmaps, only do it if absolutely necessary. */
433 if (vr
->equiv
== NULL
435 vr
->equiv
= BITMAP_ALLOC (NULL
);
437 if (equiv
!= vr
->equiv
)
439 if (equiv
&& !bitmap_empty_p (equiv
))
440 bitmap_copy (vr
->equiv
, equiv
);
442 bitmap_clear (vr
->equiv
);
447 /* Set value range VR to the canonical form of {T, MIN, MAX, EQUIV}.
448 This means adjusting T, MIN and MAX representing the case of a
449 wrapping range with MAX < MIN covering [MIN, type_max] U [type_min, MAX]
450 as anti-rage ~[MAX+1, MIN-1]. Likewise for wrapping anti-ranges.
451 In corner cases where MAX+1 or MIN-1 wraps this will fall back
453 This routine exists to ease canonicalization in the case where we
454 extract ranges from var + CST op limit. */
457 set_and_canonicalize_value_range (value_range_t
*vr
, enum value_range_type t
,
458 tree min
, tree max
, bitmap equiv
)
460 /* Nothing to canonicalize for symbolic or unknown or varying ranges. */
462 && t
!= VR_ANTI_RANGE
)
463 || TREE_CODE (min
) != INTEGER_CST
464 || TREE_CODE (max
) != INTEGER_CST
)
466 set_value_range (vr
, t
, min
, max
, equiv
);
470 /* Wrong order for min and max, to swap them and the VR type we need
472 if (tree_int_cst_lt (max
, min
))
474 tree one
= build_int_cst (TREE_TYPE (min
), 1);
475 tree tmp
= int_const_binop (PLUS_EXPR
, max
, one
);
476 max
= int_const_binop (MINUS_EXPR
, min
, one
);
479 /* There's one corner case, if we had [C+1, C] before we now have
480 that again. But this represents an empty value range, so drop
481 to varying in this case. */
482 if (tree_int_cst_lt (max
, min
))
484 set_value_range_to_varying (vr
);
488 t
= t
== VR_RANGE
? VR_ANTI_RANGE
: VR_RANGE
;
491 /* Anti-ranges that can be represented as ranges should be so. */
492 if (t
== VR_ANTI_RANGE
)
494 bool is_min
= vrp_val_is_min (min
);
495 bool is_max
= vrp_val_is_max (max
);
497 if (is_min
&& is_max
)
499 /* We cannot deal with empty ranges, drop to varying. */
500 set_value_range_to_varying (vr
);
504 /* As a special exception preserve non-null ranges. */
505 && !(TYPE_UNSIGNED (TREE_TYPE (min
))
506 && integer_zerop (max
)))
508 tree one
= build_int_cst (TREE_TYPE (max
), 1);
509 min
= int_const_binop (PLUS_EXPR
, max
, one
);
510 max
= vrp_val_max (TREE_TYPE (max
));
515 tree one
= build_int_cst (TREE_TYPE (min
), 1);
516 max
= int_const_binop (MINUS_EXPR
, min
, one
);
517 min
= vrp_val_min (TREE_TYPE (min
));
522 set_value_range (vr
, t
, min
, max
, equiv
);
525 /* Copy value range FROM into value range TO. */
528 copy_value_range (value_range_t
*to
, value_range_t
*from
)
530 set_value_range (to
, from
->type
, from
->min
, from
->max
, from
->equiv
);
533 /* Set value range VR to a single value. This function is only called
534 with values we get from statements, and exists to clear the
535 TREE_OVERFLOW flag so that we don't think we have an overflow
536 infinity when we shouldn't. */
539 set_value_range_to_value (value_range_t
*vr
, tree val
, bitmap equiv
)
541 gcc_assert (is_gimple_min_invariant (val
));
542 val
= avoid_overflow_infinity (val
);
543 set_value_range (vr
, VR_RANGE
, val
, val
, equiv
);
546 /* Set value range VR to a non-negative range of type TYPE.
547 OVERFLOW_INFINITY indicates whether to use an overflow infinity
548 rather than TYPE_MAX_VALUE; this should be true if we determine
549 that the range is nonnegative based on the assumption that signed
550 overflow does not occur. */
553 set_value_range_to_nonnegative (value_range_t
*vr
, tree type
,
554 bool overflow_infinity
)
558 if (overflow_infinity
&& !supports_overflow_infinity (type
))
560 set_value_range_to_varying (vr
);
564 zero
= build_int_cst (type
, 0);
565 set_value_range (vr
, VR_RANGE
, zero
,
567 ? positive_overflow_infinity (type
)
568 : TYPE_MAX_VALUE (type
)),
572 /* Set value range VR to a non-NULL range of type TYPE. */
575 set_value_range_to_nonnull (value_range_t
*vr
, tree type
)
577 tree zero
= build_int_cst (type
, 0);
578 set_value_range (vr
, VR_ANTI_RANGE
, zero
, zero
, vr
->equiv
);
582 /* Set value range VR to a NULL range of type TYPE. */
585 set_value_range_to_null (value_range_t
*vr
, tree type
)
587 set_value_range_to_value (vr
, build_int_cst (type
, 0), vr
->equiv
);
591 /* Set value range VR to a range of a truthvalue of type TYPE. */
594 set_value_range_to_truthvalue (value_range_t
*vr
, tree type
)
596 if (TYPE_PRECISION (type
) == 1)
597 set_value_range_to_varying (vr
);
599 set_value_range (vr
, VR_RANGE
,
600 build_int_cst (type
, 0), build_int_cst (type
, 1),
605 /* Set value range VR to VR_UNDEFINED. */
608 set_value_range_to_undefined (value_range_t
*vr
)
610 vr
->type
= VR_UNDEFINED
;
611 vr
->min
= vr
->max
= NULL_TREE
;
613 bitmap_clear (vr
->equiv
);
617 /* If abs (min) < abs (max), set VR to [-max, max], if
618 abs (min) >= abs (max), set VR to [-min, min]. */
621 abs_extent_range (value_range_t
*vr
, tree min
, tree max
)
625 gcc_assert (TREE_CODE (min
) == INTEGER_CST
);
626 gcc_assert (TREE_CODE (max
) == INTEGER_CST
);
627 gcc_assert (INTEGRAL_TYPE_P (TREE_TYPE (min
)));
628 gcc_assert (!TYPE_UNSIGNED (TREE_TYPE (min
)));
629 min
= fold_unary (ABS_EXPR
, TREE_TYPE (min
), min
);
630 max
= fold_unary (ABS_EXPR
, TREE_TYPE (max
), max
);
631 if (TREE_OVERFLOW (min
) || TREE_OVERFLOW (max
))
633 set_value_range_to_varying (vr
);
636 cmp
= compare_values (min
, max
);
638 min
= fold_unary (NEGATE_EXPR
, TREE_TYPE (min
), max
);
639 else if (cmp
== 0 || cmp
== 1)
642 min
= fold_unary (NEGATE_EXPR
, TREE_TYPE (min
), min
);
646 set_value_range_to_varying (vr
);
649 set_and_canonicalize_value_range (vr
, VR_RANGE
, min
, max
, NULL
);
653 /* Return value range information for VAR.
655 If we have no values ranges recorded (ie, VRP is not running), then
656 return NULL. Otherwise create an empty range if none existed for VAR. */
658 static value_range_t
*
659 get_value_range (const_tree var
)
663 unsigned ver
= SSA_NAME_VERSION (var
);
665 /* If we have no recorded ranges, then return NULL. */
673 /* Create a default value range. */
674 vr_value
[ver
] = vr
= XCNEW (value_range_t
);
676 /* Defer allocating the equivalence set. */
679 /* If VAR is a default definition, the variable can take any value
681 sym
= SSA_NAME_VAR (var
);
682 if (SSA_NAME_IS_DEFAULT_DEF (var
))
684 /* Try to use the "nonnull" attribute to create ~[0, 0]
685 anti-ranges for pointers. Note that this is only valid with
686 default definitions of PARM_DECLs. */
687 if (TREE_CODE (sym
) == PARM_DECL
688 && POINTER_TYPE_P (TREE_TYPE (sym
))
689 && nonnull_arg_p (sym
))
690 set_value_range_to_nonnull (vr
, TREE_TYPE (sym
));
692 set_value_range_to_varying (vr
);
698 /* Return true, if VAL1 and VAL2 are equal values for VRP purposes. */
701 vrp_operand_equal_p (const_tree val1
, const_tree val2
)
705 if (!val1
|| !val2
|| !operand_equal_p (val1
, val2
, 0))
707 if (is_overflow_infinity (val1
))
708 return is_overflow_infinity (val2
);
712 /* Return true, if the bitmaps B1 and B2 are equal. */
715 vrp_bitmap_equal_p (const_bitmap b1
, const_bitmap b2
)
718 || ((!b1
|| bitmap_empty_p (b1
))
719 && (!b2
|| bitmap_empty_p (b2
)))
721 && bitmap_equal_p (b1
, b2
)));
724 /* Update the value range and equivalence set for variable VAR to
725 NEW_VR. Return true if NEW_VR is different from VAR's previous
728 NOTE: This function assumes that NEW_VR is a temporary value range
729 object created for the sole purpose of updating VAR's range. The
730 storage used by the equivalence set from NEW_VR will be freed by
731 this function. Do not call update_value_range when NEW_VR
732 is the range object associated with another SSA name. */
735 update_value_range (const_tree var
, value_range_t
*new_vr
)
737 value_range_t
*old_vr
;
740 /* Update the value range, if necessary. */
741 old_vr
= get_value_range (var
);
742 is_new
= old_vr
->type
!= new_vr
->type
743 || !vrp_operand_equal_p (old_vr
->min
, new_vr
->min
)
744 || !vrp_operand_equal_p (old_vr
->max
, new_vr
->max
)
745 || !vrp_bitmap_equal_p (old_vr
->equiv
, new_vr
->equiv
);
748 set_value_range (old_vr
, new_vr
->type
, new_vr
->min
, new_vr
->max
,
751 BITMAP_FREE (new_vr
->equiv
);
757 /* Add VAR and VAR's equivalence set to EQUIV. This is the central
758 point where equivalence processing can be turned on/off. */
761 add_equivalence (bitmap
*equiv
, const_tree var
)
763 unsigned ver
= SSA_NAME_VERSION (var
);
764 value_range_t
*vr
= vr_value
[ver
];
767 *equiv
= BITMAP_ALLOC (NULL
);
768 bitmap_set_bit (*equiv
, ver
);
770 bitmap_ior_into (*equiv
, vr
->equiv
);
774 /* Return true if VR is ~[0, 0]. */
777 range_is_nonnull (value_range_t
*vr
)
779 return vr
->type
== VR_ANTI_RANGE
780 && integer_zerop (vr
->min
)
781 && integer_zerop (vr
->max
);
785 /* Return true if VR is [0, 0]. */
788 range_is_null (value_range_t
*vr
)
790 return vr
->type
== VR_RANGE
791 && integer_zerop (vr
->min
)
792 && integer_zerop (vr
->max
);
795 /* Return true if max and min of VR are INTEGER_CST. It's not necessary
799 range_int_cst_p (value_range_t
*vr
)
801 return (vr
->type
== VR_RANGE
802 && TREE_CODE (vr
->max
) == INTEGER_CST
803 && TREE_CODE (vr
->min
) == INTEGER_CST
804 && !TREE_OVERFLOW (vr
->max
)
805 && !TREE_OVERFLOW (vr
->min
));
808 /* Return true if VR is a INTEGER_CST singleton. */
811 range_int_cst_singleton_p (value_range_t
*vr
)
813 return (range_int_cst_p (vr
)
814 && tree_int_cst_equal (vr
->min
, vr
->max
));
817 /* Return true if value range VR involves at least one symbol. */
820 symbolic_range_p (value_range_t
*vr
)
822 return (!is_gimple_min_invariant (vr
->min
)
823 || !is_gimple_min_invariant (vr
->max
));
826 /* Return true if value range VR uses an overflow infinity. */
829 overflow_infinity_range_p (value_range_t
*vr
)
831 return (vr
->type
== VR_RANGE
832 && (is_overflow_infinity (vr
->min
)
833 || is_overflow_infinity (vr
->max
)));
836 /* Return false if we can not make a valid comparison based on VR;
837 this will be the case if it uses an overflow infinity and overflow
838 is not undefined (i.e., -fno-strict-overflow is in effect).
839 Otherwise return true, and set *STRICT_OVERFLOW_P to true if VR
840 uses an overflow infinity. */
843 usable_range_p (value_range_t
*vr
, bool *strict_overflow_p
)
845 gcc_assert (vr
->type
== VR_RANGE
);
846 if (is_overflow_infinity (vr
->min
))
848 *strict_overflow_p
= true;
849 if (!TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (vr
->min
)))
852 if (is_overflow_infinity (vr
->max
))
854 *strict_overflow_p
= true;
855 if (!TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (vr
->max
)))
862 /* Like tree_expr_nonnegative_warnv_p, but this function uses value
863 ranges obtained so far. */
866 vrp_expr_computes_nonnegative (tree expr
, bool *strict_overflow_p
)
868 return (tree_expr_nonnegative_warnv_p (expr
, strict_overflow_p
)
869 || (TREE_CODE (expr
) == SSA_NAME
870 && ssa_name_nonnegative_p (expr
)));
873 /* Return true if the result of assignment STMT is know to be non-negative.
874 If the return value is based on the assumption that signed overflow is
875 undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't change
876 *STRICT_OVERFLOW_P.*/
879 gimple_assign_nonnegative_warnv_p (gimple stmt
, bool *strict_overflow_p
)
881 enum tree_code code
= gimple_assign_rhs_code (stmt
);
882 switch (get_gimple_rhs_class (code
))
884 case GIMPLE_UNARY_RHS
:
885 return tree_unary_nonnegative_warnv_p (gimple_assign_rhs_code (stmt
),
886 gimple_expr_type (stmt
),
887 gimple_assign_rhs1 (stmt
),
889 case GIMPLE_BINARY_RHS
:
890 return tree_binary_nonnegative_warnv_p (gimple_assign_rhs_code (stmt
),
891 gimple_expr_type (stmt
),
892 gimple_assign_rhs1 (stmt
),
893 gimple_assign_rhs2 (stmt
),
895 case GIMPLE_TERNARY_RHS
:
897 case GIMPLE_SINGLE_RHS
:
898 return tree_single_nonnegative_warnv_p (gimple_assign_rhs1 (stmt
),
900 case GIMPLE_INVALID_RHS
:
907 /* Return true if return value of call STMT is know to be non-negative.
908 If the return value is based on the assumption that signed overflow is
909 undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't change
910 *STRICT_OVERFLOW_P.*/
913 gimple_call_nonnegative_warnv_p (gimple stmt
, bool *strict_overflow_p
)
915 tree arg0
= gimple_call_num_args (stmt
) > 0 ?
916 gimple_call_arg (stmt
, 0) : NULL_TREE
;
917 tree arg1
= gimple_call_num_args (stmt
) > 1 ?
918 gimple_call_arg (stmt
, 1) : NULL_TREE
;
920 return tree_call_nonnegative_warnv_p (gimple_expr_type (stmt
),
921 gimple_call_fndecl (stmt
),
927 /* Return true if STMT is know to to compute a non-negative value.
928 If the return value is based on the assumption that signed overflow is
929 undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't change
930 *STRICT_OVERFLOW_P.*/
933 gimple_stmt_nonnegative_warnv_p (gimple stmt
, bool *strict_overflow_p
)
935 switch (gimple_code (stmt
))
938 return gimple_assign_nonnegative_warnv_p (stmt
, strict_overflow_p
);
940 return gimple_call_nonnegative_warnv_p (stmt
, strict_overflow_p
);
946 /* Return true if the result of assignment STMT is know to be non-zero.
947 If the return value is based on the assumption that signed overflow is
948 undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't change
949 *STRICT_OVERFLOW_P.*/
952 gimple_assign_nonzero_warnv_p (gimple stmt
, bool *strict_overflow_p
)
954 enum tree_code code
= gimple_assign_rhs_code (stmt
);
955 switch (get_gimple_rhs_class (code
))
957 case GIMPLE_UNARY_RHS
:
958 return tree_unary_nonzero_warnv_p (gimple_assign_rhs_code (stmt
),
959 gimple_expr_type (stmt
),
960 gimple_assign_rhs1 (stmt
),
962 case GIMPLE_BINARY_RHS
:
963 return tree_binary_nonzero_warnv_p (gimple_assign_rhs_code (stmt
),
964 gimple_expr_type (stmt
),
965 gimple_assign_rhs1 (stmt
),
966 gimple_assign_rhs2 (stmt
),
968 case GIMPLE_TERNARY_RHS
:
970 case GIMPLE_SINGLE_RHS
:
971 return tree_single_nonzero_warnv_p (gimple_assign_rhs1 (stmt
),
973 case GIMPLE_INVALID_RHS
:
980 /* Return true if STMT is know to to compute a non-zero value.
981 If the return value is based on the assumption that signed overflow is
982 undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't change
983 *STRICT_OVERFLOW_P.*/
986 gimple_stmt_nonzero_warnv_p (gimple stmt
, bool *strict_overflow_p
)
988 switch (gimple_code (stmt
))
991 return gimple_assign_nonzero_warnv_p (stmt
, strict_overflow_p
);
993 return gimple_alloca_call_p (stmt
);
999 /* Like tree_expr_nonzero_warnv_p, but this function uses value ranges
1003 vrp_stmt_computes_nonzero (gimple stmt
, bool *strict_overflow_p
)
1005 if (gimple_stmt_nonzero_warnv_p (stmt
, strict_overflow_p
))
1008 /* If we have an expression of the form &X->a, then the expression
1009 is nonnull if X is nonnull. */
1010 if (is_gimple_assign (stmt
)
1011 && gimple_assign_rhs_code (stmt
) == ADDR_EXPR
)
1013 tree expr
= gimple_assign_rhs1 (stmt
);
1014 tree base
= get_base_address (TREE_OPERAND (expr
, 0));
1016 if (base
!= NULL_TREE
1017 && TREE_CODE (base
) == MEM_REF
1018 && TREE_CODE (TREE_OPERAND (base
, 0)) == SSA_NAME
)
1020 value_range_t
*vr
= get_value_range (TREE_OPERAND (base
, 0));
1021 if (range_is_nonnull (vr
))
1029 /* Returns true if EXPR is a valid value (as expected by compare_values) --
1030 a gimple invariant, or SSA_NAME +- CST. */
1033 valid_value_p (tree expr
)
1035 if (TREE_CODE (expr
) == SSA_NAME
)
1038 if (TREE_CODE (expr
) == PLUS_EXPR
1039 || TREE_CODE (expr
) == MINUS_EXPR
)
1040 return (TREE_CODE (TREE_OPERAND (expr
, 0)) == SSA_NAME
1041 && TREE_CODE (TREE_OPERAND (expr
, 1)) == INTEGER_CST
);
1043 return is_gimple_min_invariant (expr
);
1049 -2 if those are incomparable. */
1051 operand_less_p (tree val
, tree val2
)
1053 /* LT is folded faster than GE and others. Inline the common case. */
1054 if (TREE_CODE (val
) == INTEGER_CST
&& TREE_CODE (val2
) == INTEGER_CST
)
1056 if (TYPE_UNSIGNED (TREE_TYPE (val
)))
1057 return INT_CST_LT_UNSIGNED (val
, val2
);
1060 if (INT_CST_LT (val
, val2
))
1068 fold_defer_overflow_warnings ();
1070 tcmp
= fold_binary_to_constant (LT_EXPR
, boolean_type_node
, val
, val2
);
1072 fold_undefer_and_ignore_overflow_warnings ();
1075 || TREE_CODE (tcmp
) != INTEGER_CST
)
1078 if (!integer_zerop (tcmp
))
1082 /* val >= val2, not considering overflow infinity. */
1083 if (is_negative_overflow_infinity (val
))
1084 return is_negative_overflow_infinity (val2
) ? 0 : 1;
1085 else if (is_positive_overflow_infinity (val2
))
1086 return is_positive_overflow_infinity (val
) ? 0 : 1;
1091 /* Compare two values VAL1 and VAL2. Return
1093 -2 if VAL1 and VAL2 cannot be compared at compile-time,
1096 +1 if VAL1 > VAL2, and
1099 This is similar to tree_int_cst_compare but supports pointer values
1100 and values that cannot be compared at compile time.
1102 If STRICT_OVERFLOW_P is not NULL, then set *STRICT_OVERFLOW_P to
1103 true if the return value is only valid if we assume that signed
1104 overflow is undefined. */
1107 compare_values_warnv (tree val1
, tree val2
, bool *strict_overflow_p
)
1112 /* Below we rely on the fact that VAL1 and VAL2 are both pointers or
1114 gcc_assert (POINTER_TYPE_P (TREE_TYPE (val1
))
1115 == POINTER_TYPE_P (TREE_TYPE (val2
)));
1116 /* Convert the two values into the same type. This is needed because
1117 sizetype causes sign extension even for unsigned types. */
1118 val2
= fold_convert (TREE_TYPE (val1
), val2
);
1119 STRIP_USELESS_TYPE_CONVERSION (val2
);
1121 if ((TREE_CODE (val1
) == SSA_NAME
1122 || TREE_CODE (val1
) == PLUS_EXPR
1123 || TREE_CODE (val1
) == MINUS_EXPR
)
1124 && (TREE_CODE (val2
) == SSA_NAME
1125 || TREE_CODE (val2
) == PLUS_EXPR
1126 || TREE_CODE (val2
) == MINUS_EXPR
))
1128 tree n1
, c1
, n2
, c2
;
1129 enum tree_code code1
, code2
;
1131 /* If VAL1 and VAL2 are of the form 'NAME [+-] CST' or 'NAME',
1132 return -1 or +1 accordingly. If VAL1 and VAL2 don't use the
1133 same name, return -2. */
1134 if (TREE_CODE (val1
) == SSA_NAME
)
1142 code1
= TREE_CODE (val1
);
1143 n1
= TREE_OPERAND (val1
, 0);
1144 c1
= TREE_OPERAND (val1
, 1);
1145 if (tree_int_cst_sgn (c1
) == -1)
1147 if (is_negative_overflow_infinity (c1
))
1149 c1
= fold_unary_to_constant (NEGATE_EXPR
, TREE_TYPE (c1
), c1
);
1152 code1
= code1
== MINUS_EXPR
? PLUS_EXPR
: MINUS_EXPR
;
1156 if (TREE_CODE (val2
) == SSA_NAME
)
1164 code2
= TREE_CODE (val2
);
1165 n2
= TREE_OPERAND (val2
, 0);
1166 c2
= TREE_OPERAND (val2
, 1);
1167 if (tree_int_cst_sgn (c2
) == -1)
1169 if (is_negative_overflow_infinity (c2
))
1171 c2
= fold_unary_to_constant (NEGATE_EXPR
, TREE_TYPE (c2
), c2
);
1174 code2
= code2
== MINUS_EXPR
? PLUS_EXPR
: MINUS_EXPR
;
1178 /* Both values must use the same name. */
1182 if (code1
== SSA_NAME
1183 && code2
== SSA_NAME
)
1187 /* If overflow is defined we cannot simplify more. */
1188 if (!TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (val1
)))
1191 if (strict_overflow_p
!= NULL
1192 && (code1
== SSA_NAME
|| !TREE_NO_WARNING (val1
))
1193 && (code2
== SSA_NAME
|| !TREE_NO_WARNING (val2
)))
1194 *strict_overflow_p
= true;
1196 if (code1
== SSA_NAME
)
1198 if (code2
== PLUS_EXPR
)
1199 /* NAME < NAME + CST */
1201 else if (code2
== MINUS_EXPR
)
1202 /* NAME > NAME - CST */
1205 else if (code1
== PLUS_EXPR
)
1207 if (code2
== SSA_NAME
)
1208 /* NAME + CST > NAME */
1210 else if (code2
== PLUS_EXPR
)
1211 /* NAME + CST1 > NAME + CST2, if CST1 > CST2 */
1212 return compare_values_warnv (c1
, c2
, strict_overflow_p
);
1213 else if (code2
== MINUS_EXPR
)
1214 /* NAME + CST1 > NAME - CST2 */
1217 else if (code1
== MINUS_EXPR
)
1219 if (code2
== SSA_NAME
)
1220 /* NAME - CST < NAME */
1222 else if (code2
== PLUS_EXPR
)
1223 /* NAME - CST1 < NAME + CST2 */
1225 else if (code2
== MINUS_EXPR
)
1226 /* NAME - CST1 > NAME - CST2, if CST1 < CST2. Notice that
1227 C1 and C2 are swapped in the call to compare_values. */
1228 return compare_values_warnv (c2
, c1
, strict_overflow_p
);
1234 /* We cannot compare non-constants. */
1235 if (!is_gimple_min_invariant (val1
) || !is_gimple_min_invariant (val2
))
1238 if (!POINTER_TYPE_P (TREE_TYPE (val1
)))
1240 /* We cannot compare overflowed values, except for overflow
1242 if (TREE_OVERFLOW (val1
) || TREE_OVERFLOW (val2
))
1244 if (strict_overflow_p
!= NULL
)
1245 *strict_overflow_p
= true;
1246 if (is_negative_overflow_infinity (val1
))
1247 return is_negative_overflow_infinity (val2
) ? 0 : -1;
1248 else if (is_negative_overflow_infinity (val2
))
1250 else if (is_positive_overflow_infinity (val1
))
1251 return is_positive_overflow_infinity (val2
) ? 0 : 1;
1252 else if (is_positive_overflow_infinity (val2
))
1257 return tree_int_cst_compare (val1
, val2
);
1263 /* First see if VAL1 and VAL2 are not the same. */
1264 if (val1
== val2
|| operand_equal_p (val1
, val2
, 0))
1267 /* If VAL1 is a lower address than VAL2, return -1. */
1268 if (operand_less_p (val1
, val2
) == 1)
1271 /* If VAL1 is a higher address than VAL2, return +1. */
1272 if (operand_less_p (val2
, val1
) == 1)
1275 /* If VAL1 is different than VAL2, return +2.
1276 For integer constants we either have already returned -1 or 1
1277 or they are equivalent. We still might succeed in proving
1278 something about non-trivial operands. */
1279 if (TREE_CODE (val1
) != INTEGER_CST
1280 || TREE_CODE (val2
) != INTEGER_CST
)
1282 t
= fold_binary_to_constant (NE_EXPR
, boolean_type_node
, val1
, val2
);
1283 if (t
&& integer_onep (t
))
1291 /* Compare values like compare_values_warnv, but treat comparisons of
1292 nonconstants which rely on undefined overflow as incomparable. */
1295 compare_values (tree val1
, tree val2
)
1301 ret
= compare_values_warnv (val1
, val2
, &sop
);
1303 && (!is_gimple_min_invariant (val1
) || !is_gimple_min_invariant (val2
)))
1309 /* Return 1 if VAL is inside value range VR (VR->MIN <= VAL <= VR->MAX),
1310 0 if VAL is not inside VR,
1311 -2 if we cannot tell either way.
1313 FIXME, the current semantics of this functions are a bit quirky
1314 when taken in the context of VRP. In here we do not care
1315 about VR's type. If VR is the anti-range ~[3, 5] the call
1316 value_inside_range (4, VR) will return 1.
1318 This is counter-intuitive in a strict sense, but the callers
1319 currently expect this. They are calling the function
1320 merely to determine whether VR->MIN <= VAL <= VR->MAX. The
1321 callers are applying the VR_RANGE/VR_ANTI_RANGE semantics
1324 This also applies to value_ranges_intersect_p and
1325 range_includes_zero_p. The semantics of VR_RANGE and
1326 VR_ANTI_RANGE should be encoded here, but that also means
1327 adapting the users of these functions to the new semantics.
1329 Benchmark compile/20001226-1.c compilation time after changing this
1333 value_inside_range (tree val
, value_range_t
* vr
)
1337 cmp1
= operand_less_p (val
, vr
->min
);
1343 cmp2
= operand_less_p (vr
->max
, val
);
1351 /* Return true if value ranges VR0 and VR1 have a non-empty
1354 Benchmark compile/20001226-1.c compilation time after changing this
1359 value_ranges_intersect_p (value_range_t
*vr0
, value_range_t
*vr1
)
1361 /* The value ranges do not intersect if the maximum of the first range is
1362 less than the minimum of the second range or vice versa.
1363 When those relations are unknown, we can't do any better. */
1364 if (operand_less_p (vr0
->max
, vr1
->min
) != 0)
1366 if (operand_less_p (vr1
->max
, vr0
->min
) != 0)
1372 /* Return true if VR includes the value zero, false otherwise. FIXME,
1373 currently this will return false for an anti-range like ~[-4, 3].
1374 This will be wrong when the semantics of value_inside_range are
1375 modified (currently the users of this function expect these
1379 range_includes_zero_p (value_range_t
*vr
)
1383 gcc_assert (vr
->type
!= VR_UNDEFINED
1384 && vr
->type
!= VR_VARYING
1385 && !symbolic_range_p (vr
));
1387 zero
= build_int_cst (TREE_TYPE (vr
->min
), 0);
1388 return (value_inside_range (zero
, vr
) == 1);
1391 /* Return true if T, an SSA_NAME, is known to be nonnegative. Return
1392 false otherwise or if no value range information is available. */
1395 ssa_name_nonnegative_p (const_tree t
)
1397 value_range_t
*vr
= get_value_range (t
);
1399 if (INTEGRAL_TYPE_P (t
)
1400 && TYPE_UNSIGNED (t
))
1406 /* Testing for VR_ANTI_RANGE is not useful here as any anti-range
1407 which would return a useful value should be encoded as a VR_RANGE. */
1408 if (vr
->type
== VR_RANGE
)
1410 int result
= compare_values (vr
->min
, integer_zero_node
);
1412 return (result
== 0 || result
== 1);
1417 /* If OP has a value range with a single constant value return that,
1418 otherwise return NULL_TREE. This returns OP itself if OP is a
1422 op_with_constant_singleton_value_range (tree op
)
1426 if (is_gimple_min_invariant (op
))
1429 if (TREE_CODE (op
) != SSA_NAME
)
1432 vr
= get_value_range (op
);
1433 if (vr
->type
== VR_RANGE
1434 && operand_equal_p (vr
->min
, vr
->max
, 0)
1435 && is_gimple_min_invariant (vr
->min
))
1442 /* Extract value range information from an ASSERT_EXPR EXPR and store
1446 extract_range_from_assert (value_range_t
*vr_p
, tree expr
)
1448 tree var
, cond
, limit
, min
, max
, type
;
1449 value_range_t
*var_vr
, *limit_vr
;
1450 enum tree_code cond_code
;
1452 var
= ASSERT_EXPR_VAR (expr
);
1453 cond
= ASSERT_EXPR_COND (expr
);
1455 gcc_assert (COMPARISON_CLASS_P (cond
));
1457 /* Find VAR in the ASSERT_EXPR conditional. */
1458 if (var
== TREE_OPERAND (cond
, 0)
1459 || TREE_CODE (TREE_OPERAND (cond
, 0)) == PLUS_EXPR
1460 || TREE_CODE (TREE_OPERAND (cond
, 0)) == NOP_EXPR
)
1462 /* If the predicate is of the form VAR COMP LIMIT, then we just
1463 take LIMIT from the RHS and use the same comparison code. */
1464 cond_code
= TREE_CODE (cond
);
1465 limit
= TREE_OPERAND (cond
, 1);
1466 cond
= TREE_OPERAND (cond
, 0);
1470 /* If the predicate is of the form LIMIT COMP VAR, then we need
1471 to flip around the comparison code to create the proper range
1473 cond_code
= swap_tree_comparison (TREE_CODE (cond
));
1474 limit
= TREE_OPERAND (cond
, 0);
1475 cond
= TREE_OPERAND (cond
, 1);
1478 limit
= avoid_overflow_infinity (limit
);
1480 type
= TREE_TYPE (limit
);
1481 gcc_assert (limit
!= var
);
1483 /* For pointer arithmetic, we only keep track of pointer equality
1485 if (POINTER_TYPE_P (type
) && cond_code
!= NE_EXPR
&& cond_code
!= EQ_EXPR
)
1487 set_value_range_to_varying (vr_p
);
1491 /* If LIMIT is another SSA name and LIMIT has a range of its own,
1492 try to use LIMIT's range to avoid creating symbolic ranges
1494 limit_vr
= (TREE_CODE (limit
) == SSA_NAME
) ? get_value_range (limit
) : NULL
;
1496 /* LIMIT's range is only interesting if it has any useful information. */
1498 && (limit_vr
->type
== VR_UNDEFINED
1499 || limit_vr
->type
== VR_VARYING
1500 || symbolic_range_p (limit_vr
)))
1503 /* Initially, the new range has the same set of equivalences of
1504 VAR's range. This will be revised before returning the final
1505 value. Since assertions may be chained via mutually exclusive
1506 predicates, we will need to trim the set of equivalences before
1508 gcc_assert (vr_p
->equiv
== NULL
);
1509 add_equivalence (&vr_p
->equiv
, var
);
1511 /* Extract a new range based on the asserted comparison for VAR and
1512 LIMIT's value range. Notice that if LIMIT has an anti-range, we
1513 will only use it for equality comparisons (EQ_EXPR). For any
1514 other kind of assertion, we cannot derive a range from LIMIT's
1515 anti-range that can be used to describe the new range. For
1516 instance, ASSERT_EXPR <x_2, x_2 <= b_4>. If b_4 is ~[2, 10],
1517 then b_4 takes on the ranges [-INF, 1] and [11, +INF]. There is
1518 no single range for x_2 that could describe LE_EXPR, so we might
1519 as well build the range [b_4, +INF] for it.
1520 One special case we handle is extracting a range from a
1521 range test encoded as (unsigned)var + CST <= limit. */
1522 if (TREE_CODE (cond
) == NOP_EXPR
1523 || TREE_CODE (cond
) == PLUS_EXPR
)
1525 if (TREE_CODE (cond
) == PLUS_EXPR
)
1527 min
= fold_build1 (NEGATE_EXPR
, TREE_TYPE (TREE_OPERAND (cond
, 1)),
1528 TREE_OPERAND (cond
, 1));
1529 max
= int_const_binop (PLUS_EXPR
, limit
, min
);
1530 cond
= TREE_OPERAND (cond
, 0);
1534 min
= build_int_cst (TREE_TYPE (var
), 0);
1538 /* Make sure to not set TREE_OVERFLOW on the final type
1539 conversion. We are willingly interpreting large positive
1540 unsigned values as negative singed values here. */
1541 min
= force_fit_type_double (TREE_TYPE (var
), tree_to_double_int (min
),
1543 max
= force_fit_type_double (TREE_TYPE (var
), tree_to_double_int (max
),
1546 /* We can transform a max, min range to an anti-range or
1547 vice-versa. Use set_and_canonicalize_value_range which does
1549 if (cond_code
== LE_EXPR
)
1550 set_and_canonicalize_value_range (vr_p
, VR_RANGE
,
1551 min
, max
, vr_p
->equiv
);
1552 else if (cond_code
== GT_EXPR
)
1553 set_and_canonicalize_value_range (vr_p
, VR_ANTI_RANGE
,
1554 min
, max
, vr_p
->equiv
);
1558 else if (cond_code
== EQ_EXPR
)
1560 enum value_range_type range_type
;
1564 range_type
= limit_vr
->type
;
1565 min
= limit_vr
->min
;
1566 max
= limit_vr
->max
;
1570 range_type
= VR_RANGE
;
1575 set_value_range (vr_p
, range_type
, min
, max
, vr_p
->equiv
);
1577 /* When asserting the equality VAR == LIMIT and LIMIT is another
1578 SSA name, the new range will also inherit the equivalence set
1580 if (TREE_CODE (limit
) == SSA_NAME
)
1581 add_equivalence (&vr_p
->equiv
, limit
);
1583 else if (cond_code
== NE_EXPR
)
1585 /* As described above, when LIMIT's range is an anti-range and
1586 this assertion is an inequality (NE_EXPR), then we cannot
1587 derive anything from the anti-range. For instance, if
1588 LIMIT's range was ~[0, 0], the assertion 'VAR != LIMIT' does
1589 not imply that VAR's range is [0, 0]. So, in the case of
1590 anti-ranges, we just assert the inequality using LIMIT and
1593 If LIMIT_VR is a range, we can only use it to build a new
1594 anti-range if LIMIT_VR is a single-valued range. For
1595 instance, if LIMIT_VR is [0, 1], the predicate
1596 VAR != [0, 1] does not mean that VAR's range is ~[0, 1].
1597 Rather, it means that for value 0 VAR should be ~[0, 0]
1598 and for value 1, VAR should be ~[1, 1]. We cannot
1599 represent these ranges.
1601 The only situation in which we can build a valid
1602 anti-range is when LIMIT_VR is a single-valued range
1603 (i.e., LIMIT_VR->MIN == LIMIT_VR->MAX). In that case,
1604 build the anti-range ~[LIMIT_VR->MIN, LIMIT_VR->MAX]. */
1606 && limit_vr
->type
== VR_RANGE
1607 && compare_values (limit_vr
->min
, limit_vr
->max
) == 0)
1609 min
= limit_vr
->min
;
1610 max
= limit_vr
->max
;
1614 /* In any other case, we cannot use LIMIT's range to build a
1615 valid anti-range. */
1619 /* If MIN and MAX cover the whole range for their type, then
1620 just use the original LIMIT. */
1621 if (INTEGRAL_TYPE_P (type
)
1622 && vrp_val_is_min (min
)
1623 && vrp_val_is_max (max
))
1626 set_value_range (vr_p
, VR_ANTI_RANGE
, min
, max
, vr_p
->equiv
);
1628 else if (cond_code
== LE_EXPR
|| cond_code
== LT_EXPR
)
1630 min
= TYPE_MIN_VALUE (type
);
1632 if (limit_vr
== NULL
|| limit_vr
->type
== VR_ANTI_RANGE
)
1636 /* If LIMIT_VR is of the form [N1, N2], we need to build the
1637 range [MIN, N2] for LE_EXPR and [MIN, N2 - 1] for
1639 max
= limit_vr
->max
;
1642 /* If the maximum value forces us to be out of bounds, simply punt.
1643 It would be pointless to try and do anything more since this
1644 all should be optimized away above us. */
1645 if ((cond_code
== LT_EXPR
1646 && compare_values (max
, min
) == 0)
1647 || (CONSTANT_CLASS_P (max
) && TREE_OVERFLOW (max
)))
1648 set_value_range_to_varying (vr_p
);
1651 /* For LT_EXPR, we create the range [MIN, MAX - 1]. */
1652 if (cond_code
== LT_EXPR
)
1654 tree one
= build_int_cst (type
, 1);
1655 max
= fold_build2 (MINUS_EXPR
, type
, max
, one
);
1657 TREE_NO_WARNING (max
) = 1;
1660 set_value_range (vr_p
, VR_RANGE
, min
, max
, vr_p
->equiv
);
1663 else if (cond_code
== GE_EXPR
|| cond_code
== GT_EXPR
)
1665 max
= TYPE_MAX_VALUE (type
);
1667 if (limit_vr
== NULL
|| limit_vr
->type
== VR_ANTI_RANGE
)
1671 /* If LIMIT_VR is of the form [N1, N2], we need to build the
1672 range [N1, MAX] for GE_EXPR and [N1 + 1, MAX] for
1674 min
= limit_vr
->min
;
1677 /* If the minimum value forces us to be out of bounds, simply punt.
1678 It would be pointless to try and do anything more since this
1679 all should be optimized away above us. */
1680 if ((cond_code
== GT_EXPR
1681 && compare_values (min
, max
) == 0)
1682 || (CONSTANT_CLASS_P (min
) && TREE_OVERFLOW (min
)))
1683 set_value_range_to_varying (vr_p
);
1686 /* For GT_EXPR, we create the range [MIN + 1, MAX]. */
1687 if (cond_code
== GT_EXPR
)
1689 tree one
= build_int_cst (type
, 1);
1690 min
= fold_build2 (PLUS_EXPR
, type
, min
, one
);
1692 TREE_NO_WARNING (min
) = 1;
1695 set_value_range (vr_p
, VR_RANGE
, min
, max
, vr_p
->equiv
);
1701 /* If VAR already had a known range, it may happen that the new
1702 range we have computed and VAR's range are not compatible. For
1706 p_6 = ASSERT_EXPR <p_5, p_5 == NULL>;
1708 p_8 = ASSERT_EXPR <p_6, p_6 != NULL>;
1710 While the above comes from a faulty program, it will cause an ICE
1711 later because p_8 and p_6 will have incompatible ranges and at
1712 the same time will be considered equivalent. A similar situation
1716 i_6 = ASSERT_EXPR <i_5, i_5 > 10>;
1718 i_7 = ASSERT_EXPR <i_6, i_6 < 5>;
1720 Again i_6 and i_7 will have incompatible ranges. It would be
1721 pointless to try and do anything with i_7's range because
1722 anything dominated by 'if (i_5 < 5)' will be optimized away.
1723 Note, due to the wa in which simulation proceeds, the statement
1724 i_7 = ASSERT_EXPR <...> we would never be visited because the
1725 conditional 'if (i_5 < 5)' always evaluates to false. However,
1726 this extra check does not hurt and may protect against future
1727 changes to VRP that may get into a situation similar to the
1728 NULL pointer dereference example.
1730 Note that these compatibility tests are only needed when dealing
1731 with ranges or a mix of range and anti-range. If VAR_VR and VR_P
1732 are both anti-ranges, they will always be compatible, because two
1733 anti-ranges will always have a non-empty intersection. */
1735 var_vr
= get_value_range (var
);
1737 /* We may need to make adjustments when VR_P and VAR_VR are numeric
1738 ranges or anti-ranges. */
1739 if (vr_p
->type
== VR_VARYING
1740 || vr_p
->type
== VR_UNDEFINED
1741 || var_vr
->type
== VR_VARYING
1742 || var_vr
->type
== VR_UNDEFINED
1743 || symbolic_range_p (vr_p
)
1744 || symbolic_range_p (var_vr
))
1747 if (var_vr
->type
== VR_RANGE
&& vr_p
->type
== VR_RANGE
)
1749 /* If the two ranges have a non-empty intersection, we can
1750 refine the resulting range. Since the assert expression
1751 creates an equivalency and at the same time it asserts a
1752 predicate, we can take the intersection of the two ranges to
1753 get better precision. */
1754 if (value_ranges_intersect_p (var_vr
, vr_p
))
1756 /* Use the larger of the two minimums. */
1757 if (compare_values (vr_p
->min
, var_vr
->min
) == -1)
1762 /* Use the smaller of the two maximums. */
1763 if (compare_values (vr_p
->max
, var_vr
->max
) == 1)
1768 set_value_range (vr_p
, vr_p
->type
, min
, max
, vr_p
->equiv
);
1772 /* The two ranges do not intersect, set the new range to
1773 VARYING, because we will not be able to do anything
1774 meaningful with it. */
1775 set_value_range_to_varying (vr_p
);
1778 else if ((var_vr
->type
== VR_RANGE
&& vr_p
->type
== VR_ANTI_RANGE
)
1779 || (var_vr
->type
== VR_ANTI_RANGE
&& vr_p
->type
== VR_RANGE
))
1781 /* A range and an anti-range will cancel each other only if
1782 their ends are the same. For instance, in the example above,
1783 p_8's range ~[0, 0] and p_6's range [0, 0] are incompatible,
1784 so VR_P should be set to VR_VARYING. */
1785 if (compare_values (var_vr
->min
, vr_p
->min
) == 0
1786 && compare_values (var_vr
->max
, vr_p
->max
) == 0)
1787 set_value_range_to_varying (vr_p
);
1790 tree min
, max
, anti_min
, anti_max
, real_min
, real_max
;
1793 /* We want to compute the logical AND of the two ranges;
1794 there are three cases to consider.
1797 1. The VR_ANTI_RANGE range is completely within the
1798 VR_RANGE and the endpoints of the ranges are
1799 different. In that case the resulting range
1800 should be whichever range is more precise.
1801 Typically that will be the VR_RANGE.
1803 2. The VR_ANTI_RANGE is completely disjoint from
1804 the VR_RANGE. In this case the resulting range
1805 should be the VR_RANGE.
1807 3. There is some overlap between the VR_ANTI_RANGE
1810 3a. If the high limit of the VR_ANTI_RANGE resides
1811 within the VR_RANGE, then the result is a new
1812 VR_RANGE starting at the high limit of the
1813 VR_ANTI_RANGE + 1 and extending to the
1814 high limit of the original VR_RANGE.
1816 3b. If the low limit of the VR_ANTI_RANGE resides
1817 within the VR_RANGE, then the result is a new
1818 VR_RANGE starting at the low limit of the original
1819 VR_RANGE and extending to the low limit of the
1820 VR_ANTI_RANGE - 1. */
1821 if (vr_p
->type
== VR_ANTI_RANGE
)
1823 anti_min
= vr_p
->min
;
1824 anti_max
= vr_p
->max
;
1825 real_min
= var_vr
->min
;
1826 real_max
= var_vr
->max
;
1830 anti_min
= var_vr
->min
;
1831 anti_max
= var_vr
->max
;
1832 real_min
= vr_p
->min
;
1833 real_max
= vr_p
->max
;
1837 /* Case 1, VR_ANTI_RANGE completely within VR_RANGE,
1838 not including any endpoints. */
1839 if (compare_values (anti_max
, real_max
) == -1
1840 && compare_values (anti_min
, real_min
) == 1)
1842 /* If the range is covering the whole valid range of
1843 the type keep the anti-range. */
1844 if (!vrp_val_is_min (real_min
)
1845 || !vrp_val_is_max (real_max
))
1846 set_value_range (vr_p
, VR_RANGE
, real_min
,
1847 real_max
, vr_p
->equiv
);
1849 /* Case 2, VR_ANTI_RANGE completely disjoint from
1851 else if (compare_values (anti_min
, real_max
) == 1
1852 || compare_values (anti_max
, real_min
) == -1)
1854 set_value_range (vr_p
, VR_RANGE
, real_min
,
1855 real_max
, vr_p
->equiv
);
1857 /* Case 3a, the anti-range extends into the low
1858 part of the real range. Thus creating a new
1859 low for the real range. */
1860 else if (((cmp
= compare_values (anti_max
, real_min
)) == 1
1862 && compare_values (anti_max
, real_max
) == -1)
1864 gcc_assert (!is_positive_overflow_infinity (anti_max
));
1865 if (needs_overflow_infinity (TREE_TYPE (anti_max
))
1866 && vrp_val_is_max (anti_max
))
1868 if (!supports_overflow_infinity (TREE_TYPE (var_vr
->min
)))
1870 set_value_range_to_varying (vr_p
);
1873 min
= positive_overflow_infinity (TREE_TYPE (var_vr
->min
));
1875 else if (!POINTER_TYPE_P (TREE_TYPE (var_vr
->min
)))
1876 min
= fold_build2 (PLUS_EXPR
, TREE_TYPE (var_vr
->min
),
1878 build_int_cst (TREE_TYPE (var_vr
->min
), 1));
1880 min
= fold_build2 (POINTER_PLUS_EXPR
, TREE_TYPE (var_vr
->min
),
1881 anti_max
, size_int (1));
1883 set_value_range (vr_p
, VR_RANGE
, min
, max
, vr_p
->equiv
);
1885 /* Case 3b, the anti-range extends into the high
1886 part of the real range. Thus creating a new
1887 higher for the real range. */
1888 else if (compare_values (anti_min
, real_min
) == 1
1889 && ((cmp
= compare_values (anti_min
, real_max
)) == -1
1892 gcc_assert (!is_negative_overflow_infinity (anti_min
));
1893 if (needs_overflow_infinity (TREE_TYPE (anti_min
))
1894 && vrp_val_is_min (anti_min
))
1896 if (!supports_overflow_infinity (TREE_TYPE (var_vr
->min
)))
1898 set_value_range_to_varying (vr_p
);
1901 max
= negative_overflow_infinity (TREE_TYPE (var_vr
->min
));
1903 else if (!POINTER_TYPE_P (TREE_TYPE (var_vr
->min
)))
1904 max
= fold_build2 (MINUS_EXPR
, TREE_TYPE (var_vr
->min
),
1906 build_int_cst (TREE_TYPE (var_vr
->min
), 1));
1908 max
= fold_build2 (POINTER_PLUS_EXPR
, TREE_TYPE (var_vr
->min
),
1912 set_value_range (vr_p
, VR_RANGE
, min
, max
, vr_p
->equiv
);
1919 /* Extract range information from SSA name VAR and store it in VR. If
1920 VAR has an interesting range, use it. Otherwise, create the
1921 range [VAR, VAR] and return it. This is useful in situations where
1922 we may have conditionals testing values of VARYING names. For
1929 Even if y_5 is deemed VARYING, we can determine that x_3 > y_5 is
1933 extract_range_from_ssa_name (value_range_t
*vr
, tree var
)
1935 value_range_t
*var_vr
= get_value_range (var
);
1937 if (var_vr
->type
!= VR_UNDEFINED
&& var_vr
->type
!= VR_VARYING
)
1938 copy_value_range (vr
, var_vr
);
1940 set_value_range (vr
, VR_RANGE
, var
, var
, NULL
);
1942 add_equivalence (&vr
->equiv
, var
);
1946 /* Wrapper around int_const_binop. If the operation overflows and we
1947 are not using wrapping arithmetic, then adjust the result to be
1948 -INF or +INF depending on CODE, VAL1 and VAL2. This can return
1949 NULL_TREE if we need to use an overflow infinity representation but
1950 the type does not support it. */
1953 vrp_int_const_binop (enum tree_code code
, tree val1
, tree val2
)
1957 res
= int_const_binop (code
, val1
, val2
);
1959 /* If we are using unsigned arithmetic, operate symbolically
1960 on -INF and +INF as int_const_binop only handles signed overflow. */
1961 if (TYPE_UNSIGNED (TREE_TYPE (val1
)))
1963 int checkz
= compare_values (res
, val1
);
1964 bool overflow
= false;
1966 /* Ensure that res = val1 [+*] val2 >= val1
1967 or that res = val1 - val2 <= val1. */
1968 if ((code
== PLUS_EXPR
1969 && !(checkz
== 1 || checkz
== 0))
1970 || (code
== MINUS_EXPR
1971 && !(checkz
== 0 || checkz
== -1)))
1975 /* Checking for multiplication overflow is done by dividing the
1976 output of the multiplication by the first input of the
1977 multiplication. If the result of that division operation is
1978 not equal to the second input of the multiplication, then the
1979 multiplication overflowed. */
1980 else if (code
== MULT_EXPR
&& !integer_zerop (val1
))
1982 tree tmp
= int_const_binop (TRUNC_DIV_EXPR
,
1985 int check
= compare_values (tmp
, val2
);
1993 res
= copy_node (res
);
1994 TREE_OVERFLOW (res
) = 1;
1998 else if (TYPE_OVERFLOW_WRAPS (TREE_TYPE (val1
)))
1999 /* If the singed operation wraps then int_const_binop has done
2000 everything we want. */
2002 else if ((TREE_OVERFLOW (res
)
2003 && !TREE_OVERFLOW (val1
)
2004 && !TREE_OVERFLOW (val2
))
2005 || is_overflow_infinity (val1
)
2006 || is_overflow_infinity (val2
))
2008 /* If the operation overflowed but neither VAL1 nor VAL2 are
2009 overflown, return -INF or +INF depending on the operation
2010 and the combination of signs of the operands. */
2011 int sgn1
= tree_int_cst_sgn (val1
);
2012 int sgn2
= tree_int_cst_sgn (val2
);
2014 if (needs_overflow_infinity (TREE_TYPE (res
))
2015 && !supports_overflow_infinity (TREE_TYPE (res
)))
2018 /* We have to punt on adding infinities of different signs,
2019 since we can't tell what the sign of the result should be.
2020 Likewise for subtracting infinities of the same sign. */
2021 if (((code
== PLUS_EXPR
&& sgn1
!= sgn2
)
2022 || (code
== MINUS_EXPR
&& sgn1
== sgn2
))
2023 && is_overflow_infinity (val1
)
2024 && is_overflow_infinity (val2
))
2027 /* Don't try to handle division or shifting of infinities. */
2028 if ((code
== TRUNC_DIV_EXPR
2029 || code
== FLOOR_DIV_EXPR
2030 || code
== CEIL_DIV_EXPR
2031 || code
== EXACT_DIV_EXPR
2032 || code
== ROUND_DIV_EXPR
2033 || code
== RSHIFT_EXPR
)
2034 && (is_overflow_infinity (val1
)
2035 || is_overflow_infinity (val2
)))
2038 /* Notice that we only need to handle the restricted set of
2039 operations handled by extract_range_from_binary_expr.
2040 Among them, only multiplication, addition and subtraction
2041 can yield overflow without overflown operands because we
2042 are working with integral types only... except in the
2043 case VAL1 = -INF and VAL2 = -1 which overflows to +INF
2044 for division too. */
2046 /* For multiplication, the sign of the overflow is given
2047 by the comparison of the signs of the operands. */
2048 if ((code
== MULT_EXPR
&& sgn1
== sgn2
)
2049 /* For addition, the operands must be of the same sign
2050 to yield an overflow. Its sign is therefore that
2051 of one of the operands, for example the first. For
2052 infinite operands X + -INF is negative, not positive. */
2053 || (code
== PLUS_EXPR
2055 ? !is_negative_overflow_infinity (val2
)
2056 : is_positive_overflow_infinity (val2
)))
2057 /* For subtraction, non-infinite operands must be of
2058 different signs to yield an overflow. Its sign is
2059 therefore that of the first operand or the opposite of
2060 that of the second operand. A first operand of 0 counts
2061 as positive here, for the corner case 0 - (-INF), which
2062 overflows, but must yield +INF. For infinite operands 0
2063 - INF is negative, not positive. */
2064 || (code
== MINUS_EXPR
2066 ? !is_positive_overflow_infinity (val2
)
2067 : is_negative_overflow_infinity (val2
)))
2068 /* We only get in here with positive shift count, so the
2069 overflow direction is the same as the sign of val1.
2070 Actually rshift does not overflow at all, but we only
2071 handle the case of shifting overflowed -INF and +INF. */
2072 || (code
== RSHIFT_EXPR
2074 /* For division, the only case is -INF / -1 = +INF. */
2075 || code
== TRUNC_DIV_EXPR
2076 || code
== FLOOR_DIV_EXPR
2077 || code
== CEIL_DIV_EXPR
2078 || code
== EXACT_DIV_EXPR
2079 || code
== ROUND_DIV_EXPR
)
2080 return (needs_overflow_infinity (TREE_TYPE (res
))
2081 ? positive_overflow_infinity (TREE_TYPE (res
))
2082 : TYPE_MAX_VALUE (TREE_TYPE (res
)));
2084 return (needs_overflow_infinity (TREE_TYPE (res
))
2085 ? negative_overflow_infinity (TREE_TYPE (res
))
2086 : TYPE_MIN_VALUE (TREE_TYPE (res
)));
2093 /* For range VR compute two double_int bitmasks. In *MAY_BE_NONZERO
2094 bitmask if some bit is unset, it means for all numbers in the range
2095 the bit is 0, otherwise it might be 0 or 1. In *MUST_BE_NONZERO
2096 bitmask if some bit is set, it means for all numbers in the range
2097 the bit is 1, otherwise it might be 0 or 1. */
2100 zero_nonzero_bits_from_vr (value_range_t
*vr
, double_int
*may_be_nonzero
,
2101 double_int
*must_be_nonzero
)
2103 if (range_int_cst_p (vr
))
2105 if (range_int_cst_singleton_p (vr
))
2107 *may_be_nonzero
= tree_to_double_int (vr
->min
);
2108 *must_be_nonzero
= *may_be_nonzero
;
2111 if (tree_int_cst_sgn (vr
->min
) >= 0)
2113 double_int dmin
= tree_to_double_int (vr
->min
);
2114 double_int dmax
= tree_to_double_int (vr
->max
);
2115 double_int xor_mask
= double_int_xor (dmin
, dmax
);
2116 *may_be_nonzero
= double_int_ior (dmin
, dmax
);
2117 *must_be_nonzero
= double_int_and (dmin
, dmax
);
2118 if (xor_mask
.high
!= 0)
2120 unsigned HOST_WIDE_INT mask
2121 = ((unsigned HOST_WIDE_INT
) 1
2122 << floor_log2 (xor_mask
.high
)) - 1;
2123 may_be_nonzero
->low
= ALL_ONES
;
2124 may_be_nonzero
->high
|= mask
;
2125 must_be_nonzero
->low
= 0;
2126 must_be_nonzero
->high
&= ~mask
;
2128 else if (xor_mask
.low
!= 0)
2130 unsigned HOST_WIDE_INT mask
2131 = ((unsigned HOST_WIDE_INT
) 1
2132 << floor_log2 (xor_mask
.low
)) - 1;
2133 may_be_nonzero
->low
|= mask
;
2134 must_be_nonzero
->low
&= ~mask
;
2139 may_be_nonzero
->low
= ALL_ONES
;
2140 may_be_nonzero
->high
= ALL_ONES
;
2141 must_be_nonzero
->low
= 0;
2142 must_be_nonzero
->high
= 0;
2147 /* Extract range information from a binary expression EXPR based on
2148 the ranges of each of its operands and the expression code. */
2151 extract_range_from_binary_expr (value_range_t
*vr
,
2152 enum tree_code code
,
2153 tree expr_type
, tree op0
, tree op1
)
2155 enum value_range_type type
;
2158 value_range_t vr0
= { VR_UNDEFINED
, NULL_TREE
, NULL_TREE
, NULL
};
2159 value_range_t vr1
= { VR_UNDEFINED
, NULL_TREE
, NULL_TREE
, NULL
};
2161 /* Not all binary expressions can be applied to ranges in a
2162 meaningful way. Handle only arithmetic operations. */
2163 if (code
!= PLUS_EXPR
2164 && code
!= MINUS_EXPR
2165 && code
!= POINTER_PLUS_EXPR
2166 && code
!= MULT_EXPR
2167 && code
!= TRUNC_DIV_EXPR
2168 && code
!= FLOOR_DIV_EXPR
2169 && code
!= CEIL_DIV_EXPR
2170 && code
!= EXACT_DIV_EXPR
2171 && code
!= ROUND_DIV_EXPR
2172 && code
!= TRUNC_MOD_EXPR
2173 && code
!= RSHIFT_EXPR
2176 && code
!= BIT_AND_EXPR
2177 && code
!= BIT_IOR_EXPR
2178 && code
!= TRUTH_AND_EXPR
2179 && code
!= TRUTH_OR_EXPR
)
2181 /* We can still do constant propagation here. */
2182 tree const_op0
= op_with_constant_singleton_value_range (op0
);
2183 tree const_op1
= op_with_constant_singleton_value_range (op1
);
2184 if (const_op0
|| const_op1
)
2186 tree tem
= fold_binary (code
, expr_type
,
2187 const_op0
? const_op0
: op0
,
2188 const_op1
? const_op1
: op1
);
2190 && is_gimple_min_invariant (tem
)
2191 && !is_overflow_infinity (tem
))
2193 set_value_range (vr
, VR_RANGE
, tem
, tem
, NULL
);
2197 set_value_range_to_varying (vr
);
2201 /* Get value ranges for each operand. For constant operands, create
2202 a new value range with the operand to simplify processing. */
2203 if (TREE_CODE (op0
) == SSA_NAME
)
2204 vr0
= *(get_value_range (op0
));
2205 else if (is_gimple_min_invariant (op0
))
2206 set_value_range_to_value (&vr0
, op0
, NULL
);
2208 set_value_range_to_varying (&vr0
);
2210 if (TREE_CODE (op1
) == SSA_NAME
)
2211 vr1
= *(get_value_range (op1
));
2212 else if (is_gimple_min_invariant (op1
))
2213 set_value_range_to_value (&vr1
, op1
, NULL
);
2215 set_value_range_to_varying (&vr1
);
2217 /* If either range is UNDEFINED, so is the result. */
2218 if (vr0
.type
== VR_UNDEFINED
|| vr1
.type
== VR_UNDEFINED
)
2220 set_value_range_to_undefined (vr
);
2224 /* The type of the resulting value range defaults to VR0.TYPE. */
2227 /* Refuse to operate on VARYING ranges, ranges of different kinds
2228 and symbolic ranges. As an exception, we allow BIT_AND_EXPR
2229 because we may be able to derive a useful range even if one of
2230 the operands is VR_VARYING or symbolic range. Similarly for
2231 divisions. TODO, we may be able to derive anti-ranges in
2233 if (code
!= BIT_AND_EXPR
2234 && code
!= TRUTH_AND_EXPR
2235 && code
!= TRUTH_OR_EXPR
2236 && code
!= TRUNC_DIV_EXPR
2237 && code
!= FLOOR_DIV_EXPR
2238 && code
!= CEIL_DIV_EXPR
2239 && code
!= EXACT_DIV_EXPR
2240 && code
!= ROUND_DIV_EXPR
2241 && code
!= TRUNC_MOD_EXPR
2242 && (vr0
.type
== VR_VARYING
2243 || vr1
.type
== VR_VARYING
2244 || vr0
.type
!= vr1
.type
2245 || symbolic_range_p (&vr0
)
2246 || symbolic_range_p (&vr1
)))
2248 set_value_range_to_varying (vr
);
2252 /* Now evaluate the expression to determine the new range. */
2253 if (POINTER_TYPE_P (expr_type
)
2254 || POINTER_TYPE_P (TREE_TYPE (op0
))
2255 || POINTER_TYPE_P (TREE_TYPE (op1
)))
2257 if (code
== MIN_EXPR
|| code
== MAX_EXPR
)
2259 /* For MIN/MAX expressions with pointers, we only care about
2260 nullness, if both are non null, then the result is nonnull.
2261 If both are null, then the result is null. Otherwise they
2263 if (range_is_nonnull (&vr0
) && range_is_nonnull (&vr1
))
2264 set_value_range_to_nonnull (vr
, expr_type
);
2265 else if (range_is_null (&vr0
) && range_is_null (&vr1
))
2266 set_value_range_to_null (vr
, expr_type
);
2268 set_value_range_to_varying (vr
);
2272 if (code
== POINTER_PLUS_EXPR
)
2274 /* For pointer types, we are really only interested in asserting
2275 whether the expression evaluates to non-NULL. */
2276 if (range_is_nonnull (&vr0
) || range_is_nonnull (&vr1
))
2277 set_value_range_to_nonnull (vr
, expr_type
);
2278 else if (range_is_null (&vr0
) && range_is_null (&vr1
))
2279 set_value_range_to_null (vr
, expr_type
);
2281 set_value_range_to_varying (vr
);
2283 else if (code
== BIT_AND_EXPR
)
2285 /* For pointer types, we are really only interested in asserting
2286 whether the expression evaluates to non-NULL. */
2287 if (range_is_nonnull (&vr0
) && range_is_nonnull (&vr1
))
2288 set_value_range_to_nonnull (vr
, expr_type
);
2289 else if (range_is_null (&vr0
) || range_is_null (&vr1
))
2290 set_value_range_to_null (vr
, expr_type
);
2292 set_value_range_to_varying (vr
);
2300 /* For integer ranges, apply the operation to each end of the
2301 range and see what we end up with. */
2302 if (code
== TRUTH_AND_EXPR
2303 || code
== TRUTH_OR_EXPR
)
2305 /* If one of the operands is zero, we know that the whole
2306 expression evaluates zero. */
2307 if (code
== TRUTH_AND_EXPR
2308 && ((vr0
.type
== VR_RANGE
2309 && integer_zerop (vr0
.min
)
2310 && integer_zerop (vr0
.max
))
2311 || (vr1
.type
== VR_RANGE
2312 && integer_zerop (vr1
.min
)
2313 && integer_zerop (vr1
.max
))))
2316 min
= max
= build_int_cst (expr_type
, 0);
2318 /* If one of the operands is one, we know that the whole
2319 expression evaluates one. */
2320 else if (code
== TRUTH_OR_EXPR
2321 && ((vr0
.type
== VR_RANGE
2322 && integer_onep (vr0
.min
)
2323 && integer_onep (vr0
.max
))
2324 || (vr1
.type
== VR_RANGE
2325 && integer_onep (vr1
.min
)
2326 && integer_onep (vr1
.max
))))
2329 min
= max
= build_int_cst (expr_type
, 1);
2331 else if (vr0
.type
!= VR_VARYING
2332 && vr1
.type
!= VR_VARYING
2333 && vr0
.type
== vr1
.type
2334 && !symbolic_range_p (&vr0
)
2335 && !overflow_infinity_range_p (&vr0
)
2336 && !symbolic_range_p (&vr1
)
2337 && !overflow_infinity_range_p (&vr1
))
2339 /* Boolean expressions cannot be folded with int_const_binop. */
2340 min
= fold_binary (code
, expr_type
, vr0
.min
, vr1
.min
);
2341 max
= fold_binary (code
, expr_type
, vr0
.max
, vr1
.max
);
2345 /* The result of a TRUTH_*_EXPR is always true or false. */
2346 set_value_range_to_truthvalue (vr
, expr_type
);
2350 else if (code
== PLUS_EXPR
2352 || code
== MAX_EXPR
)
2354 /* If we have a PLUS_EXPR with two VR_ANTI_RANGEs, drop to
2355 VR_VARYING. It would take more effort to compute a precise
2356 range for such a case. For example, if we have op0 == 1 and
2357 op1 == -1 with their ranges both being ~[0,0], we would have
2358 op0 + op1 == 0, so we cannot claim that the sum is in ~[0,0].
2359 Note that we are guaranteed to have vr0.type == vr1.type at
2361 if (vr0
.type
== VR_ANTI_RANGE
)
2363 if (code
== PLUS_EXPR
)
2365 set_value_range_to_varying (vr
);
2368 /* For MIN_EXPR and MAX_EXPR with two VR_ANTI_RANGEs,
2369 the resulting VR_ANTI_RANGE is the same - intersection
2370 of the two ranges. */
2371 min
= vrp_int_const_binop (MAX_EXPR
, vr0
.min
, vr1
.min
);
2372 max
= vrp_int_const_binop (MIN_EXPR
, vr0
.max
, vr1
.max
);
2376 /* For operations that make the resulting range directly
2377 proportional to the original ranges, apply the operation to
2378 the same end of each range. */
2379 min
= vrp_int_const_binop (code
, vr0
.min
, vr1
.min
);
2380 max
= vrp_int_const_binop (code
, vr0
.max
, vr1
.max
);
2383 /* If both additions overflowed the range kind is still correct.
2384 This happens regularly with subtracting something in unsigned
2386 ??? See PR30318 for all the cases we do not handle. */
2387 if (code
== PLUS_EXPR
2388 && (TREE_OVERFLOW (min
) && !is_overflow_infinity (min
))
2389 && (TREE_OVERFLOW (max
) && !is_overflow_infinity (max
)))
2391 min
= build_int_cst_wide (TREE_TYPE (min
),
2392 TREE_INT_CST_LOW (min
),
2393 TREE_INT_CST_HIGH (min
));
2394 max
= build_int_cst_wide (TREE_TYPE (max
),
2395 TREE_INT_CST_LOW (max
),
2396 TREE_INT_CST_HIGH (max
));
2399 else if (code
== MULT_EXPR
2400 || code
== TRUNC_DIV_EXPR
2401 || code
== FLOOR_DIV_EXPR
2402 || code
== CEIL_DIV_EXPR
2403 || code
== EXACT_DIV_EXPR
2404 || code
== ROUND_DIV_EXPR
2405 || code
== RSHIFT_EXPR
)
2411 /* If we have an unsigned MULT_EXPR with two VR_ANTI_RANGEs,
2412 drop to VR_VARYING. It would take more effort to compute a
2413 precise range for such a case. For example, if we have
2414 op0 == 65536 and op1 == 65536 with their ranges both being
2415 ~[0,0] on a 32-bit machine, we would have op0 * op1 == 0, so
2416 we cannot claim that the product is in ~[0,0]. Note that we
2417 are guaranteed to have vr0.type == vr1.type at this
2419 if (code
== MULT_EXPR
2420 && vr0
.type
== VR_ANTI_RANGE
2421 && !TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (op0
)))
2423 set_value_range_to_varying (vr
);
2427 /* If we have a RSHIFT_EXPR with any shift values outside [0..prec-1],
2428 then drop to VR_VARYING. Outside of this range we get undefined
2429 behavior from the shift operation. We cannot even trust
2430 SHIFT_COUNT_TRUNCATED at this stage, because that applies to rtl
2431 shifts, and the operation at the tree level may be widened. */
2432 if (code
== RSHIFT_EXPR
)
2434 if (vr1
.type
== VR_ANTI_RANGE
2435 || !vrp_expr_computes_nonnegative (op1
, &sop
)
2437 (build_int_cst (TREE_TYPE (vr1
.max
),
2438 TYPE_PRECISION (expr_type
) - 1),
2441 set_value_range_to_varying (vr
);
2446 else if ((code
== TRUNC_DIV_EXPR
2447 || code
== FLOOR_DIV_EXPR
2448 || code
== CEIL_DIV_EXPR
2449 || code
== EXACT_DIV_EXPR
2450 || code
== ROUND_DIV_EXPR
)
2451 && (vr0
.type
!= VR_RANGE
|| symbolic_range_p (&vr0
)))
2453 /* For division, if op1 has VR_RANGE but op0 does not, something
2454 can be deduced just from that range. Say [min, max] / [4, max]
2455 gives [min / 4, max / 4] range. */
2456 if (vr1
.type
== VR_RANGE
2457 && !symbolic_range_p (&vr1
)
2458 && !range_includes_zero_p (&vr1
))
2460 vr0
.type
= type
= VR_RANGE
;
2461 vr0
.min
= vrp_val_min (TREE_TYPE (op0
));
2462 vr0
.max
= vrp_val_max (TREE_TYPE (op1
));
2466 set_value_range_to_varying (vr
);
2471 /* For divisions, if flag_non_call_exceptions is true, we must
2472 not eliminate a division by zero. */
2473 if ((code
== TRUNC_DIV_EXPR
2474 || code
== FLOOR_DIV_EXPR
2475 || code
== CEIL_DIV_EXPR
2476 || code
== EXACT_DIV_EXPR
2477 || code
== ROUND_DIV_EXPR
)
2478 && cfun
->can_throw_non_call_exceptions
2479 && (vr1
.type
!= VR_RANGE
2480 || symbolic_range_p (&vr1
)
2481 || range_includes_zero_p (&vr1
)))
2483 set_value_range_to_varying (vr
);
2487 /* For divisions, if op0 is VR_RANGE, we can deduce a range
2488 even if op1 is VR_VARYING, VR_ANTI_RANGE, symbolic or can
2490 if ((code
== TRUNC_DIV_EXPR
2491 || code
== FLOOR_DIV_EXPR
2492 || code
== CEIL_DIV_EXPR
2493 || code
== EXACT_DIV_EXPR
2494 || code
== ROUND_DIV_EXPR
)
2495 && vr0
.type
== VR_RANGE
2496 && (vr1
.type
!= VR_RANGE
2497 || symbolic_range_p (&vr1
)
2498 || range_includes_zero_p (&vr1
)))
2500 tree zero
= build_int_cst (TREE_TYPE (vr0
.min
), 0);
2506 if (vrp_expr_computes_nonnegative (op1
, &sop
) && !sop
)
2508 /* For unsigned division or when divisor is known
2509 to be non-negative, the range has to cover
2510 all numbers from 0 to max for positive max
2511 and all numbers from min to 0 for negative min. */
2512 cmp
= compare_values (vr0
.max
, zero
);
2515 else if (cmp
== 0 || cmp
== 1)
2519 cmp
= compare_values (vr0
.min
, zero
);
2522 else if (cmp
== 0 || cmp
== -1)
2529 /* Otherwise the range is -max .. max or min .. -min
2530 depending on which bound is bigger in absolute value,
2531 as the division can change the sign. */
2532 abs_extent_range (vr
, vr0
.min
, vr0
.max
);
2535 if (type
== VR_VARYING
)
2537 set_value_range_to_varying (vr
);
2542 /* Multiplications and divisions are a bit tricky to handle,
2543 depending on the mix of signs we have in the two ranges, we
2544 need to operate on different values to get the minimum and
2545 maximum values for the new range. One approach is to figure
2546 out all the variations of range combinations and do the
2549 However, this involves several calls to compare_values and it
2550 is pretty convoluted. It's simpler to do the 4 operations
2551 (MIN0 OP MIN1, MIN0 OP MAX1, MAX0 OP MIN1 and MAX0 OP MAX0 OP
2552 MAX1) and then figure the smallest and largest values to form
2556 gcc_assert ((vr0
.type
== VR_RANGE
2557 || (code
== MULT_EXPR
&& vr0
.type
== VR_ANTI_RANGE
))
2558 && vr0
.type
== vr1
.type
);
2560 /* Compute the 4 cross operations. */
2562 val
[0] = vrp_int_const_binop (code
, vr0
.min
, vr1
.min
);
2563 if (val
[0] == NULL_TREE
)
2566 if (vr1
.max
== vr1
.min
)
2570 val
[1] = vrp_int_const_binop (code
, vr0
.min
, vr1
.max
);
2571 if (val
[1] == NULL_TREE
)
2575 if (vr0
.max
== vr0
.min
)
2579 val
[2] = vrp_int_const_binop (code
, vr0
.max
, vr1
.min
);
2580 if (val
[2] == NULL_TREE
)
2584 if (vr0
.min
== vr0
.max
|| vr1
.min
== vr1
.max
)
2588 val
[3] = vrp_int_const_binop (code
, vr0
.max
, vr1
.max
);
2589 if (val
[3] == NULL_TREE
)
2595 set_value_range_to_varying (vr
);
2599 /* Set MIN to the minimum of VAL[i] and MAX to the maximum
2603 for (i
= 1; i
< 4; i
++)
2605 if (!is_gimple_min_invariant (min
)
2606 || (TREE_OVERFLOW (min
) && !is_overflow_infinity (min
))
2607 || !is_gimple_min_invariant (max
)
2608 || (TREE_OVERFLOW (max
) && !is_overflow_infinity (max
)))
2613 if (!is_gimple_min_invariant (val
[i
])
2614 || (TREE_OVERFLOW (val
[i
])
2615 && !is_overflow_infinity (val
[i
])))
2617 /* If we found an overflowed value, set MIN and MAX
2618 to it so that we set the resulting range to
2624 if (compare_values (val
[i
], min
) == -1)
2627 if (compare_values (val
[i
], max
) == 1)
2633 else if (code
== TRUNC_MOD_EXPR
)
2636 if (vr1
.type
!= VR_RANGE
2637 || symbolic_range_p (&vr1
)
2638 || range_includes_zero_p (&vr1
)
2639 || vrp_val_is_min (vr1
.min
))
2641 set_value_range_to_varying (vr
);
2645 /* Compute MAX <|vr1.min|, |vr1.max|> - 1. */
2646 max
= fold_unary_to_constant (ABS_EXPR
, TREE_TYPE (vr1
.min
), vr1
.min
);
2647 if (tree_int_cst_lt (max
, vr1
.max
))
2649 max
= int_const_binop (MINUS_EXPR
, max
, integer_one_node
);
2650 /* If the dividend is non-negative the modulus will be
2651 non-negative as well. */
2652 if (TYPE_UNSIGNED (TREE_TYPE (max
))
2653 || (vrp_expr_computes_nonnegative (op0
, &sop
) && !sop
))
2654 min
= build_int_cst (TREE_TYPE (max
), 0);
2656 min
= fold_unary_to_constant (NEGATE_EXPR
, TREE_TYPE (max
), max
);
2658 else if (code
== MINUS_EXPR
)
2660 /* If we have a MINUS_EXPR with two VR_ANTI_RANGEs, drop to
2661 VR_VARYING. It would take more effort to compute a precise
2662 range for such a case. For example, if we have op0 == 1 and
2663 op1 == 1 with their ranges both being ~[0,0], we would have
2664 op0 - op1 == 0, so we cannot claim that the difference is in
2665 ~[0,0]. Note that we are guaranteed to have
2666 vr0.type == vr1.type at this point. */
2667 if (vr0
.type
== VR_ANTI_RANGE
)
2669 set_value_range_to_varying (vr
);
2673 /* For MINUS_EXPR, apply the operation to the opposite ends of
2675 min
= vrp_int_const_binop (code
, vr0
.min
, vr1
.max
);
2676 max
= vrp_int_const_binop (code
, vr0
.max
, vr1
.min
);
2678 else if (code
== BIT_AND_EXPR
|| code
== BIT_IOR_EXPR
)
2680 bool vr0_int_cst_singleton_p
, vr1_int_cst_singleton_p
;
2681 bool int_cst_range0
, int_cst_range1
;
2682 double_int may_be_nonzero0
, may_be_nonzero1
;
2683 double_int must_be_nonzero0
, must_be_nonzero1
;
2685 vr0_int_cst_singleton_p
= range_int_cst_singleton_p (&vr0
);
2686 vr1_int_cst_singleton_p
= range_int_cst_singleton_p (&vr1
);
2687 int_cst_range0
= zero_nonzero_bits_from_vr (&vr0
, &may_be_nonzero0
,
2689 int_cst_range1
= zero_nonzero_bits_from_vr (&vr1
, &may_be_nonzero1
,
2693 if (vr0_int_cst_singleton_p
&& vr1_int_cst_singleton_p
)
2694 min
= max
= int_const_binop (code
, vr0
.max
, vr1
.max
);
2695 else if (!int_cst_range0
&& !int_cst_range1
)
2697 set_value_range_to_varying (vr
);
2700 else if (code
== BIT_AND_EXPR
)
2702 min
= double_int_to_tree (expr_type
,
2703 double_int_and (must_be_nonzero0
,
2705 max
= double_int_to_tree (expr_type
,
2706 double_int_and (may_be_nonzero0
,
2708 if (TREE_OVERFLOW (min
) || tree_int_cst_sgn (min
) < 0)
2710 if (TREE_OVERFLOW (max
) || tree_int_cst_sgn (max
) < 0)
2712 if (int_cst_range0
&& tree_int_cst_sgn (vr0
.min
) >= 0)
2714 if (min
== NULL_TREE
)
2715 min
= build_int_cst (expr_type
, 0);
2716 if (max
== NULL_TREE
|| tree_int_cst_lt (vr0
.max
, max
))
2719 if (int_cst_range1
&& tree_int_cst_sgn (vr1
.min
) >= 0)
2721 if (min
== NULL_TREE
)
2722 min
= build_int_cst (expr_type
, 0);
2723 if (max
== NULL_TREE
|| tree_int_cst_lt (vr1
.max
, max
))
2727 else if (!int_cst_range0
2729 || tree_int_cst_sgn (vr0
.min
) < 0
2730 || tree_int_cst_sgn (vr1
.min
) < 0)
2732 set_value_range_to_varying (vr
);
2737 min
= double_int_to_tree (expr_type
,
2738 double_int_ior (must_be_nonzero0
,
2740 max
= double_int_to_tree (expr_type
,
2741 double_int_ior (may_be_nonzero0
,
2743 if (TREE_OVERFLOW (min
) || tree_int_cst_sgn (min
) < 0)
2746 min
= vrp_int_const_binop (MAX_EXPR
, min
, vr0
.min
);
2747 if (TREE_OVERFLOW (max
) || tree_int_cst_sgn (max
) < 0)
2749 min
= vrp_int_const_binop (MAX_EXPR
, min
, vr1
.min
);
2755 /* If either MIN or MAX overflowed, then set the resulting range to
2756 VARYING. But we do accept an overflow infinity
2758 if (min
== NULL_TREE
2759 || !is_gimple_min_invariant (min
)
2760 || (TREE_OVERFLOW (min
) && !is_overflow_infinity (min
))
2762 || !is_gimple_min_invariant (max
)
2763 || (TREE_OVERFLOW (max
) && !is_overflow_infinity (max
)))
2765 set_value_range_to_varying (vr
);
2771 2) [-INF, +-INF(OVF)]
2772 3) [+-INF(OVF), +INF]
2773 4) [+-INF(OVF), +-INF(OVF)]
2774 We learn nothing when we have INF and INF(OVF) on both sides.
2775 Note that we do accept [-INF, -INF] and [+INF, +INF] without
2777 if ((vrp_val_is_min (min
) || is_overflow_infinity (min
))
2778 && (vrp_val_is_max (max
) || is_overflow_infinity (max
)))
2780 set_value_range_to_varying (vr
);
2784 cmp
= compare_values (min
, max
);
2785 if (cmp
== -2 || cmp
== 1)
2787 /* If the new range has its limits swapped around (MIN > MAX),
2788 then the operation caused one of them to wrap around, mark
2789 the new range VARYING. */
2790 set_value_range_to_varying (vr
);
2793 set_value_range (vr
, type
, min
, max
, NULL
);
2797 /* Extract range information from a unary expression EXPR based on
2798 the range of its operand and the expression code. */
2801 extract_range_from_unary_expr (value_range_t
*vr
, enum tree_code code
,
2802 tree type
, tree op0
)
2806 value_range_t vr0
= { VR_UNDEFINED
, NULL_TREE
, NULL_TREE
, NULL
};
2808 /* Refuse to operate on certain unary expressions for which we
2809 cannot easily determine a resulting range. */
2810 if (code
== FIX_TRUNC_EXPR
2811 || code
== FLOAT_EXPR
2812 || code
== BIT_NOT_EXPR
2813 || code
== CONJ_EXPR
)
2815 /* We can still do constant propagation here. */
2816 if ((op0
= op_with_constant_singleton_value_range (op0
)) != NULL_TREE
)
2818 tree tem
= fold_unary (code
, type
, op0
);
2820 && is_gimple_min_invariant (tem
)
2821 && !is_overflow_infinity (tem
))
2823 set_value_range (vr
, VR_RANGE
, tem
, tem
, NULL
);
2827 set_value_range_to_varying (vr
);
2831 /* Get value ranges for the operand. For constant operands, create
2832 a new value range with the operand to simplify processing. */
2833 if (TREE_CODE (op0
) == SSA_NAME
)
2834 vr0
= *(get_value_range (op0
));
2835 else if (is_gimple_min_invariant (op0
))
2836 set_value_range_to_value (&vr0
, op0
, NULL
);
2838 set_value_range_to_varying (&vr0
);
2840 /* If VR0 is UNDEFINED, so is the result. */
2841 if (vr0
.type
== VR_UNDEFINED
)
2843 set_value_range_to_undefined (vr
);
2847 /* Refuse to operate on symbolic ranges, or if neither operand is
2848 a pointer or integral type. */
2849 if ((!INTEGRAL_TYPE_P (TREE_TYPE (op0
))
2850 && !POINTER_TYPE_P (TREE_TYPE (op0
)))
2851 || (vr0
.type
!= VR_VARYING
2852 && symbolic_range_p (&vr0
)))
2854 set_value_range_to_varying (vr
);
2858 /* If the expression involves pointers, we are only interested in
2859 determining if it evaluates to NULL [0, 0] or non-NULL (~[0, 0]). */
2860 if (POINTER_TYPE_P (type
) || POINTER_TYPE_P (TREE_TYPE (op0
)))
2865 if (range_is_nonnull (&vr0
)
2866 || (tree_unary_nonzero_warnv_p (code
, type
, op0
, &sop
)
2868 set_value_range_to_nonnull (vr
, type
);
2869 else if (range_is_null (&vr0
))
2870 set_value_range_to_null (vr
, type
);
2872 set_value_range_to_varying (vr
);
2877 /* Handle unary expressions on integer ranges. */
2878 if (CONVERT_EXPR_CODE_P (code
)
2879 && INTEGRAL_TYPE_P (type
)
2880 && INTEGRAL_TYPE_P (TREE_TYPE (op0
)))
2882 tree inner_type
= TREE_TYPE (op0
);
2883 tree outer_type
= type
;
2885 /* If VR0 is varying and we increase the type precision, assume
2886 a full range for the following transformation. */
2887 if (vr0
.type
== VR_VARYING
2888 && TYPE_PRECISION (inner_type
) < TYPE_PRECISION (outer_type
))
2890 vr0
.type
= VR_RANGE
;
2891 vr0
.min
= TYPE_MIN_VALUE (inner_type
);
2892 vr0
.max
= TYPE_MAX_VALUE (inner_type
);
2895 /* If VR0 is a constant range or anti-range and the conversion is
2896 not truncating we can convert the min and max values and
2897 canonicalize the resulting range. Otherwise we can do the
2898 conversion if the size of the range is less than what the
2899 precision of the target type can represent and the range is
2900 not an anti-range. */
2901 if ((vr0
.type
== VR_RANGE
2902 || vr0
.type
== VR_ANTI_RANGE
)
2903 && TREE_CODE (vr0
.min
) == INTEGER_CST
2904 && TREE_CODE (vr0
.max
) == INTEGER_CST
2905 && (!is_overflow_infinity (vr0
.min
)
2906 || (vr0
.type
== VR_RANGE
2907 && TYPE_PRECISION (outer_type
) > TYPE_PRECISION (inner_type
)
2908 && needs_overflow_infinity (outer_type
)
2909 && supports_overflow_infinity (outer_type
)))
2910 && (!is_overflow_infinity (vr0
.max
)
2911 || (vr0
.type
== VR_RANGE
2912 && TYPE_PRECISION (outer_type
) > TYPE_PRECISION (inner_type
)
2913 && needs_overflow_infinity (outer_type
)
2914 && supports_overflow_infinity (outer_type
)))
2915 && (TYPE_PRECISION (outer_type
) >= TYPE_PRECISION (inner_type
)
2916 || (vr0
.type
== VR_RANGE
2917 && integer_zerop (int_const_binop (RSHIFT_EXPR
,
2918 int_const_binop (MINUS_EXPR
, vr0
.max
, vr0
.min
),
2919 size_int (TYPE_PRECISION (outer_type
)))))))
2921 tree new_min
, new_max
;
2922 new_min
= force_fit_type_double (outer_type
,
2923 tree_to_double_int (vr0
.min
),
2925 new_max
= force_fit_type_double (outer_type
,
2926 tree_to_double_int (vr0
.max
),
2928 if (is_overflow_infinity (vr0
.min
))
2929 new_min
= negative_overflow_infinity (outer_type
);
2930 if (is_overflow_infinity (vr0
.max
))
2931 new_max
= positive_overflow_infinity (outer_type
);
2932 set_and_canonicalize_value_range (vr
, vr0
.type
,
2933 new_min
, new_max
, NULL
);
2937 set_value_range_to_varying (vr
);
2941 /* Conversion of a VR_VARYING value to a wider type can result
2942 in a usable range. So wait until after we've handled conversions
2943 before dropping the result to VR_VARYING if we had a source
2944 operand that is VR_VARYING. */
2945 if (vr0
.type
== VR_VARYING
)
2947 set_value_range_to_varying (vr
);
2951 /* Apply the operation to each end of the range and see what we end
2953 if (code
== NEGATE_EXPR
2954 && !TYPE_UNSIGNED (type
))
2956 /* NEGATE_EXPR flips the range around. We need to treat
2957 TYPE_MIN_VALUE specially. */
2958 if (is_positive_overflow_infinity (vr0
.max
))
2959 min
= negative_overflow_infinity (type
);
2960 else if (is_negative_overflow_infinity (vr0
.max
))
2961 min
= positive_overflow_infinity (type
);
2962 else if (!vrp_val_is_min (vr0
.max
))
2963 min
= fold_unary_to_constant (code
, type
, vr0
.max
);
2964 else if (needs_overflow_infinity (type
))
2966 if (supports_overflow_infinity (type
)
2967 && !is_overflow_infinity (vr0
.min
)
2968 && !vrp_val_is_min (vr0
.min
))
2969 min
= positive_overflow_infinity (type
);
2972 set_value_range_to_varying (vr
);
2977 min
= TYPE_MIN_VALUE (type
);
2979 if (is_positive_overflow_infinity (vr0
.min
))
2980 max
= negative_overflow_infinity (type
);
2981 else if (is_negative_overflow_infinity (vr0
.min
))
2982 max
= positive_overflow_infinity (type
);
2983 else if (!vrp_val_is_min (vr0
.min
))
2984 max
= fold_unary_to_constant (code
, type
, vr0
.min
);
2985 else if (needs_overflow_infinity (type
))
2987 if (supports_overflow_infinity (type
))
2988 max
= positive_overflow_infinity (type
);
2991 set_value_range_to_varying (vr
);
2996 max
= TYPE_MIN_VALUE (type
);
2998 else if (code
== NEGATE_EXPR
2999 && TYPE_UNSIGNED (type
))
3001 if (!range_includes_zero_p (&vr0
))
3003 max
= fold_unary_to_constant (code
, type
, vr0
.min
);
3004 min
= fold_unary_to_constant (code
, type
, vr0
.max
);
3008 if (range_is_null (&vr0
))
3009 set_value_range_to_null (vr
, type
);
3011 set_value_range_to_varying (vr
);
3015 else if (code
== ABS_EXPR
3016 && !TYPE_UNSIGNED (type
))
3018 /* -TYPE_MIN_VALUE = TYPE_MIN_VALUE with flag_wrapv so we can't get a
3020 if (!TYPE_OVERFLOW_UNDEFINED (type
)
3021 && ((vr0
.type
== VR_RANGE
3022 && vrp_val_is_min (vr0
.min
))
3023 || (vr0
.type
== VR_ANTI_RANGE
3024 && !vrp_val_is_min (vr0
.min
)
3025 && !range_includes_zero_p (&vr0
))))
3027 set_value_range_to_varying (vr
);
3031 /* ABS_EXPR may flip the range around, if the original range
3032 included negative values. */
3033 if (is_overflow_infinity (vr0
.min
))
3034 min
= positive_overflow_infinity (type
);
3035 else if (!vrp_val_is_min (vr0
.min
))
3036 min
= fold_unary_to_constant (code
, type
, vr0
.min
);
3037 else if (!needs_overflow_infinity (type
))
3038 min
= TYPE_MAX_VALUE (type
);
3039 else if (supports_overflow_infinity (type
))
3040 min
= positive_overflow_infinity (type
);
3043 set_value_range_to_varying (vr
);
3047 if (is_overflow_infinity (vr0
.max
))
3048 max
= positive_overflow_infinity (type
);
3049 else if (!vrp_val_is_min (vr0
.max
))
3050 max
= fold_unary_to_constant (code
, type
, vr0
.max
);
3051 else if (!needs_overflow_infinity (type
))
3052 max
= TYPE_MAX_VALUE (type
);
3053 else if (supports_overflow_infinity (type
)
3054 /* We shouldn't generate [+INF, +INF] as set_value_range
3055 doesn't like this and ICEs. */
3056 && !is_positive_overflow_infinity (min
))
3057 max
= positive_overflow_infinity (type
);
3060 set_value_range_to_varying (vr
);
3064 cmp
= compare_values (min
, max
);
3066 /* If a VR_ANTI_RANGEs contains zero, then we have
3067 ~[-INF, min(MIN, MAX)]. */
3068 if (vr0
.type
== VR_ANTI_RANGE
)
3070 if (range_includes_zero_p (&vr0
))
3072 /* Take the lower of the two values. */
3076 /* Create ~[-INF, min (abs(MIN), abs(MAX))]
3077 or ~[-INF + 1, min (abs(MIN), abs(MAX))] when
3078 flag_wrapv is set and the original anti-range doesn't include
3079 TYPE_MIN_VALUE, remember -TYPE_MIN_VALUE = TYPE_MIN_VALUE. */
3080 if (TYPE_OVERFLOW_WRAPS (type
))
3082 tree type_min_value
= TYPE_MIN_VALUE (type
);
3084 min
= (vr0
.min
!= type_min_value
3085 ? int_const_binop (PLUS_EXPR
, type_min_value
,
3091 if (overflow_infinity_range_p (&vr0
))
3092 min
= negative_overflow_infinity (type
);
3094 min
= TYPE_MIN_VALUE (type
);
3099 /* All else has failed, so create the range [0, INF], even for
3100 flag_wrapv since TYPE_MIN_VALUE is in the original
3102 vr0
.type
= VR_RANGE
;
3103 min
= build_int_cst (type
, 0);
3104 if (needs_overflow_infinity (type
))
3106 if (supports_overflow_infinity (type
))
3107 max
= positive_overflow_infinity (type
);
3110 set_value_range_to_varying (vr
);
3115 max
= TYPE_MAX_VALUE (type
);
3119 /* If the range contains zero then we know that the minimum value in the
3120 range will be zero. */
3121 else if (range_includes_zero_p (&vr0
))
3125 min
= build_int_cst (type
, 0);
3129 /* If the range was reversed, swap MIN and MAX. */
3140 /* Otherwise, operate on each end of the range. */
3141 min
= fold_unary_to_constant (code
, type
, vr0
.min
);
3142 max
= fold_unary_to_constant (code
, type
, vr0
.max
);
3144 if (needs_overflow_infinity (type
))
3146 gcc_assert (code
!= NEGATE_EXPR
&& code
!= ABS_EXPR
);
3148 /* If both sides have overflowed, we don't know
3150 if ((is_overflow_infinity (vr0
.min
)
3151 || TREE_OVERFLOW (min
))
3152 && (is_overflow_infinity (vr0
.max
)
3153 || TREE_OVERFLOW (max
)))
3155 set_value_range_to_varying (vr
);
3159 if (is_overflow_infinity (vr0
.min
))
3161 else if (TREE_OVERFLOW (min
))
3163 if (supports_overflow_infinity (type
))
3164 min
= (tree_int_cst_sgn (min
) >= 0
3165 ? positive_overflow_infinity (TREE_TYPE (min
))
3166 : negative_overflow_infinity (TREE_TYPE (min
)));
3169 set_value_range_to_varying (vr
);
3174 if (is_overflow_infinity (vr0
.max
))
3176 else if (TREE_OVERFLOW (max
))
3178 if (supports_overflow_infinity (type
))
3179 max
= (tree_int_cst_sgn (max
) >= 0
3180 ? positive_overflow_infinity (TREE_TYPE (max
))
3181 : negative_overflow_infinity (TREE_TYPE (max
)));
3184 set_value_range_to_varying (vr
);
3191 cmp
= compare_values (min
, max
);
3192 if (cmp
== -2 || cmp
== 1)
3194 /* If the new range has its limits swapped around (MIN > MAX),
3195 then the operation caused one of them to wrap around, mark
3196 the new range VARYING. */
3197 set_value_range_to_varying (vr
);
3200 set_value_range (vr
, vr0
.type
, min
, max
, NULL
);
3204 /* Extract range information from a conditional expression EXPR based on
3205 the ranges of each of its operands and the expression code. */
3208 extract_range_from_cond_expr (value_range_t
*vr
, tree expr
)
3211 value_range_t vr0
= { VR_UNDEFINED
, NULL_TREE
, NULL_TREE
, NULL
};
3212 value_range_t vr1
= { VR_UNDEFINED
, NULL_TREE
, NULL_TREE
, NULL
};
3214 /* Get value ranges for each operand. For constant operands, create
3215 a new value range with the operand to simplify processing. */
3216 op0
= COND_EXPR_THEN (expr
);
3217 if (TREE_CODE (op0
) == SSA_NAME
)
3218 vr0
= *(get_value_range (op0
));
3219 else if (is_gimple_min_invariant (op0
))
3220 set_value_range_to_value (&vr0
, op0
, NULL
);
3222 set_value_range_to_varying (&vr0
);
3224 op1
= COND_EXPR_ELSE (expr
);
3225 if (TREE_CODE (op1
) == SSA_NAME
)
3226 vr1
= *(get_value_range (op1
));
3227 else if (is_gimple_min_invariant (op1
))
3228 set_value_range_to_value (&vr1
, op1
, NULL
);
3230 set_value_range_to_varying (&vr1
);
3232 /* The resulting value range is the union of the operand ranges */
3233 vrp_meet (&vr0
, &vr1
);
3234 copy_value_range (vr
, &vr0
);
3238 /* Extract range information from a comparison expression EXPR based
3239 on the range of its operand and the expression code. */
3242 extract_range_from_comparison (value_range_t
*vr
, enum tree_code code
,
3243 tree type
, tree op0
, tree op1
)
3248 val
= vrp_evaluate_conditional_warnv_with_ops (code
, op0
, op1
, false, &sop
,
3251 /* A disadvantage of using a special infinity as an overflow
3252 representation is that we lose the ability to record overflow
3253 when we don't have an infinity. So we have to ignore a result
3254 which relies on overflow. */
3256 if (val
&& !is_overflow_infinity (val
) && !sop
)
3258 /* Since this expression was found on the RHS of an assignment,
3259 its type may be different from _Bool. Convert VAL to EXPR's
3261 val
= fold_convert (type
, val
);
3262 if (is_gimple_min_invariant (val
))
3263 set_value_range_to_value (vr
, val
, vr
->equiv
);
3265 set_value_range (vr
, VR_RANGE
, val
, val
, vr
->equiv
);
3268 /* The result of a comparison is always true or false. */
3269 set_value_range_to_truthvalue (vr
, type
);
3272 /* Try to derive a nonnegative or nonzero range out of STMT relying
3273 primarily on generic routines in fold in conjunction with range data.
3274 Store the result in *VR */
3277 extract_range_basic (value_range_t
*vr
, gimple stmt
)
3280 tree type
= gimple_expr_type (stmt
);
3282 if (INTEGRAL_TYPE_P (type
)
3283 && gimple_stmt_nonnegative_warnv_p (stmt
, &sop
))
3284 set_value_range_to_nonnegative (vr
, type
,
3285 sop
|| stmt_overflow_infinity (stmt
));
3286 else if (vrp_stmt_computes_nonzero (stmt
, &sop
)
3288 set_value_range_to_nonnull (vr
, type
);
3290 set_value_range_to_varying (vr
);
3294 /* Try to compute a useful range out of assignment STMT and store it
3298 extract_range_from_assignment (value_range_t
*vr
, gimple stmt
)
3300 enum tree_code code
= gimple_assign_rhs_code (stmt
);
3302 if (code
== ASSERT_EXPR
)
3303 extract_range_from_assert (vr
, gimple_assign_rhs1 (stmt
));
3304 else if (code
== SSA_NAME
)
3305 extract_range_from_ssa_name (vr
, gimple_assign_rhs1 (stmt
));
3306 else if (TREE_CODE_CLASS (code
) == tcc_binary
3307 || code
== TRUTH_AND_EXPR
3308 || code
== TRUTH_OR_EXPR
3309 || code
== TRUTH_XOR_EXPR
)
3310 extract_range_from_binary_expr (vr
, gimple_assign_rhs_code (stmt
),
3311 gimple_expr_type (stmt
),
3312 gimple_assign_rhs1 (stmt
),
3313 gimple_assign_rhs2 (stmt
));
3314 else if (TREE_CODE_CLASS (code
) == tcc_unary
)
3315 extract_range_from_unary_expr (vr
, gimple_assign_rhs_code (stmt
),
3316 gimple_expr_type (stmt
),
3317 gimple_assign_rhs1 (stmt
));
3318 else if (code
== COND_EXPR
)
3319 extract_range_from_cond_expr (vr
, gimple_assign_rhs1 (stmt
));
3320 else if (TREE_CODE_CLASS (code
) == tcc_comparison
)
3321 extract_range_from_comparison (vr
, gimple_assign_rhs_code (stmt
),
3322 gimple_expr_type (stmt
),
3323 gimple_assign_rhs1 (stmt
),
3324 gimple_assign_rhs2 (stmt
));
3325 else if (get_gimple_rhs_class (code
) == GIMPLE_SINGLE_RHS
3326 && is_gimple_min_invariant (gimple_assign_rhs1 (stmt
)))
3327 set_value_range_to_value (vr
, gimple_assign_rhs1 (stmt
), NULL
);
3329 set_value_range_to_varying (vr
);
3331 if (vr
->type
== VR_VARYING
)
3332 extract_range_basic (vr
, stmt
);
3335 /* Given a range VR, a LOOP and a variable VAR, determine whether it
3336 would be profitable to adjust VR using scalar evolution information
3337 for VAR. If so, update VR with the new limits. */
3340 adjust_range_with_scev (value_range_t
*vr
, struct loop
*loop
,
3341 gimple stmt
, tree var
)
3343 tree init
, step
, chrec
, tmin
, tmax
, min
, max
, type
, tem
;
3344 enum ev_direction dir
;
3346 /* TODO. Don't adjust anti-ranges. An anti-range may provide
3347 better opportunities than a regular range, but I'm not sure. */
3348 if (vr
->type
== VR_ANTI_RANGE
)
3351 chrec
= instantiate_parameters (loop
, analyze_scalar_evolution (loop
, var
));
3353 /* Like in PR19590, scev can return a constant function. */
3354 if (is_gimple_min_invariant (chrec
))
3356 set_value_range_to_value (vr
, chrec
, vr
->equiv
);
3360 if (TREE_CODE (chrec
) != POLYNOMIAL_CHREC
)
3363 init
= initial_condition_in_loop_num (chrec
, loop
->num
);
3364 tem
= op_with_constant_singleton_value_range (init
);
3367 step
= evolution_part_in_loop_num (chrec
, loop
->num
);
3368 tem
= op_with_constant_singleton_value_range (step
);
3372 /* If STEP is symbolic, we can't know whether INIT will be the
3373 minimum or maximum value in the range. Also, unless INIT is
3374 a simple expression, compare_values and possibly other functions
3375 in tree-vrp won't be able to handle it. */
3376 if (step
== NULL_TREE
3377 || !is_gimple_min_invariant (step
)
3378 || !valid_value_p (init
))
3381 dir
= scev_direction (chrec
);
3382 if (/* Do not adjust ranges if we do not know whether the iv increases
3383 or decreases, ... */
3384 dir
== EV_DIR_UNKNOWN
3385 /* ... or if it may wrap. */
3386 || scev_probably_wraps_p (init
, step
, stmt
, get_chrec_loop (chrec
),
3390 /* We use TYPE_MIN_VALUE and TYPE_MAX_VALUE here instead of
3391 negative_overflow_infinity and positive_overflow_infinity,
3392 because we have concluded that the loop probably does not
3395 type
= TREE_TYPE (var
);
3396 if (POINTER_TYPE_P (type
) || !TYPE_MIN_VALUE (type
))
3397 tmin
= lower_bound_in_type (type
, type
);
3399 tmin
= TYPE_MIN_VALUE (type
);
3400 if (POINTER_TYPE_P (type
) || !TYPE_MAX_VALUE (type
))
3401 tmax
= upper_bound_in_type (type
, type
);
3403 tmax
= TYPE_MAX_VALUE (type
);
3405 /* Try to use estimated number of iterations for the loop to constrain the
3406 final value in the evolution.
3407 We are interested in the number of executions of the latch, while
3408 nb_iterations_upper_bound includes the last execution of the exit test. */
3409 if (TREE_CODE (step
) == INTEGER_CST
3410 && loop
->any_upper_bound
3411 && !double_int_zero_p (loop
->nb_iterations_upper_bound
)
3412 && is_gimple_val (init
)
3413 && (TREE_CODE (init
) != SSA_NAME
3414 || get_value_range (init
)->type
== VR_RANGE
))
3416 value_range_t maxvr
= { VR_UNDEFINED
, NULL_TREE
, NULL_TREE
, NULL
};
3418 bool unsigned_p
= TYPE_UNSIGNED (TREE_TYPE (step
));
3421 dtmp
= double_int_mul_with_sign (tree_to_double_int (step
),
3423 loop
->nb_iterations_upper_bound
,
3425 unsigned_p
, &overflow
);
3426 tem
= double_int_to_tree (TREE_TYPE (init
), dtmp
);
3427 /* If the multiplication overflowed we can't do a meaningful
3429 if (!overflow
&& double_int_equal_p (dtmp
, tree_to_double_int (tem
)))
3431 extract_range_from_binary_expr (&maxvr
, PLUS_EXPR
,
3432 TREE_TYPE (init
), init
, tem
);
3433 /* Likewise if the addition did. */
3434 if (maxvr
.type
== VR_RANGE
)
3442 if (vr
->type
== VR_VARYING
|| vr
->type
== VR_UNDEFINED
)
3447 /* For VARYING or UNDEFINED ranges, just about anything we get
3448 from scalar evolutions should be better. */
3450 if (dir
== EV_DIR_DECREASES
)
3455 /* If we would create an invalid range, then just assume we
3456 know absolutely nothing. This may be over-conservative,
3457 but it's clearly safe, and should happen only in unreachable
3458 parts of code, or for invalid programs. */
3459 if (compare_values (min
, max
) == 1)
3462 set_value_range (vr
, VR_RANGE
, min
, max
, vr
->equiv
);
3464 else if (vr
->type
== VR_RANGE
)
3469 if (dir
== EV_DIR_DECREASES
)
3471 /* INIT is the maximum value. If INIT is lower than VR->MAX
3472 but no smaller than VR->MIN, set VR->MAX to INIT. */
3473 if (compare_values (init
, max
) == -1)
3476 /* According to the loop information, the variable does not
3477 overflow. If we think it does, probably because of an
3478 overflow due to arithmetic on a different INF value,
3480 if (is_negative_overflow_infinity (min
)
3481 || compare_values (min
, tmin
) == -1)
3487 /* If INIT is bigger than VR->MIN, set VR->MIN to INIT. */
3488 if (compare_values (init
, min
) == 1)
3491 if (is_positive_overflow_infinity (max
)
3492 || compare_values (tmax
, max
) == -1)
3496 /* If we just created an invalid range with the minimum
3497 greater than the maximum, we fail conservatively.
3498 This should happen only in unreachable
3499 parts of code, or for invalid programs. */
3500 if (compare_values (min
, max
) == 1)
3503 set_value_range (vr
, VR_RANGE
, min
, max
, vr
->equiv
);
3507 /* Return true if VAR may overflow at STMT. This checks any available
3508 loop information to see if we can determine that VAR does not
3512 vrp_var_may_overflow (tree var
, gimple stmt
)
3515 tree chrec
, init
, step
;
3517 if (current_loops
== NULL
)
3520 l
= loop_containing_stmt (stmt
);
3525 chrec
= instantiate_parameters (l
, analyze_scalar_evolution (l
, var
));
3526 if (TREE_CODE (chrec
) != POLYNOMIAL_CHREC
)
3529 init
= initial_condition_in_loop_num (chrec
, l
->num
);
3530 step
= evolution_part_in_loop_num (chrec
, l
->num
);
3532 if (step
== NULL_TREE
3533 || !is_gimple_min_invariant (step
)
3534 || !valid_value_p (init
))
3537 /* If we get here, we know something useful about VAR based on the
3538 loop information. If it wraps, it may overflow. */
3540 if (scev_probably_wraps_p (init
, step
, stmt
, get_chrec_loop (chrec
),
3544 if (dump_file
&& (dump_flags
& TDF_DETAILS
) != 0)
3546 print_generic_expr (dump_file
, var
, 0);
3547 fprintf (dump_file
, ": loop information indicates does not overflow\n");
3554 /* Given two numeric value ranges VR0, VR1 and a comparison code COMP:
3556 - Return BOOLEAN_TRUE_NODE if VR0 COMP VR1 always returns true for
3557 all the values in the ranges.
3559 - Return BOOLEAN_FALSE_NODE if the comparison always returns false.
3561 - Return NULL_TREE if it is not always possible to determine the
3562 value of the comparison.
3564 Also set *STRICT_OVERFLOW_P to indicate whether a range with an
3565 overflow infinity was used in the test. */
3569 compare_ranges (enum tree_code comp
, value_range_t
*vr0
, value_range_t
*vr1
,
3570 bool *strict_overflow_p
)
3572 /* VARYING or UNDEFINED ranges cannot be compared. */
3573 if (vr0
->type
== VR_VARYING
3574 || vr0
->type
== VR_UNDEFINED
3575 || vr1
->type
== VR_VARYING
3576 || vr1
->type
== VR_UNDEFINED
)
3579 /* Anti-ranges need to be handled separately. */
3580 if (vr0
->type
== VR_ANTI_RANGE
|| vr1
->type
== VR_ANTI_RANGE
)
3582 /* If both are anti-ranges, then we cannot compute any
3584 if (vr0
->type
== VR_ANTI_RANGE
&& vr1
->type
== VR_ANTI_RANGE
)
3587 /* These comparisons are never statically computable. */
3594 /* Equality can be computed only between a range and an
3595 anti-range. ~[VAL1, VAL2] == [VAL1, VAL2] is always false. */
3596 if (vr0
->type
== VR_RANGE
)
3598 /* To simplify processing, make VR0 the anti-range. */
3599 value_range_t
*tmp
= vr0
;
3604 gcc_assert (comp
== NE_EXPR
|| comp
== EQ_EXPR
);
3606 if (compare_values_warnv (vr0
->min
, vr1
->min
, strict_overflow_p
) == 0
3607 && compare_values_warnv (vr0
->max
, vr1
->max
, strict_overflow_p
) == 0)
3608 return (comp
== NE_EXPR
) ? boolean_true_node
: boolean_false_node
;
3613 if (!usable_range_p (vr0
, strict_overflow_p
)
3614 || !usable_range_p (vr1
, strict_overflow_p
))
3617 /* Simplify processing. If COMP is GT_EXPR or GE_EXPR, switch the
3618 operands around and change the comparison code. */
3619 if (comp
== GT_EXPR
|| comp
== GE_EXPR
)
3622 comp
= (comp
== GT_EXPR
) ? LT_EXPR
: LE_EXPR
;
3628 if (comp
== EQ_EXPR
)
3630 /* Equality may only be computed if both ranges represent
3631 exactly one value. */
3632 if (compare_values_warnv (vr0
->min
, vr0
->max
, strict_overflow_p
) == 0
3633 && compare_values_warnv (vr1
->min
, vr1
->max
, strict_overflow_p
) == 0)
3635 int cmp_min
= compare_values_warnv (vr0
->min
, vr1
->min
,
3637 int cmp_max
= compare_values_warnv (vr0
->max
, vr1
->max
,
3639 if (cmp_min
== 0 && cmp_max
== 0)
3640 return boolean_true_node
;
3641 else if (cmp_min
!= -2 && cmp_max
!= -2)
3642 return boolean_false_node
;
3644 /* If [V0_MIN, V1_MAX] < [V1_MIN, V1_MAX] then V0 != V1. */
3645 else if (compare_values_warnv (vr0
->min
, vr1
->max
,
3646 strict_overflow_p
) == 1
3647 || compare_values_warnv (vr1
->min
, vr0
->max
,
3648 strict_overflow_p
) == 1)
3649 return boolean_false_node
;
3653 else if (comp
== NE_EXPR
)
3657 /* If VR0 is completely to the left or completely to the right
3658 of VR1, they are always different. Notice that we need to
3659 make sure that both comparisons yield similar results to
3660 avoid comparing values that cannot be compared at
3662 cmp1
= compare_values_warnv (vr0
->max
, vr1
->min
, strict_overflow_p
);
3663 cmp2
= compare_values_warnv (vr0
->min
, vr1
->max
, strict_overflow_p
);
3664 if ((cmp1
== -1 && cmp2
== -1) || (cmp1
== 1 && cmp2
== 1))
3665 return boolean_true_node
;
3667 /* If VR0 and VR1 represent a single value and are identical,
3669 else if (compare_values_warnv (vr0
->min
, vr0
->max
,
3670 strict_overflow_p
) == 0
3671 && compare_values_warnv (vr1
->min
, vr1
->max
,
3672 strict_overflow_p
) == 0
3673 && compare_values_warnv (vr0
->min
, vr1
->min
,
3674 strict_overflow_p
) == 0
3675 && compare_values_warnv (vr0
->max
, vr1
->max
,
3676 strict_overflow_p
) == 0)
3677 return boolean_false_node
;
3679 /* Otherwise, they may or may not be different. */
3683 else if (comp
== LT_EXPR
|| comp
== LE_EXPR
)
3687 /* If VR0 is to the left of VR1, return true. */
3688 tst
= compare_values_warnv (vr0
->max
, vr1
->min
, strict_overflow_p
);
3689 if ((comp
== LT_EXPR
&& tst
== -1)
3690 || (comp
== LE_EXPR
&& (tst
== -1 || tst
== 0)))
3692 if (overflow_infinity_range_p (vr0
)
3693 || overflow_infinity_range_p (vr1
))
3694 *strict_overflow_p
= true;
3695 return boolean_true_node
;
3698 /* If VR0 is to the right of VR1, return false. */
3699 tst
= compare_values_warnv (vr0
->min
, vr1
->max
, strict_overflow_p
);
3700 if ((comp
== LT_EXPR
&& (tst
== 0 || tst
== 1))
3701 || (comp
== LE_EXPR
&& tst
== 1))
3703 if (overflow_infinity_range_p (vr0
)
3704 || overflow_infinity_range_p (vr1
))
3705 *strict_overflow_p
= true;
3706 return boolean_false_node
;
3709 /* Otherwise, we don't know. */
3717 /* Given a value range VR, a value VAL and a comparison code COMP, return
3718 BOOLEAN_TRUE_NODE if VR COMP VAL always returns true for all the
3719 values in VR. Return BOOLEAN_FALSE_NODE if the comparison
3720 always returns false. Return NULL_TREE if it is not always
3721 possible to determine the value of the comparison. Also set
3722 *STRICT_OVERFLOW_P to indicate whether a range with an overflow
3723 infinity was used in the test. */
3726 compare_range_with_value (enum tree_code comp
, value_range_t
*vr
, tree val
,
3727 bool *strict_overflow_p
)
3729 if (vr
->type
== VR_VARYING
|| vr
->type
== VR_UNDEFINED
)
3732 /* Anti-ranges need to be handled separately. */
3733 if (vr
->type
== VR_ANTI_RANGE
)
3735 /* For anti-ranges, the only predicates that we can compute at
3736 compile time are equality and inequality. */
3743 /* ~[VAL_1, VAL_2] OP VAL is known if VAL_1 <= VAL <= VAL_2. */
3744 if (value_inside_range (val
, vr
) == 1)
3745 return (comp
== NE_EXPR
) ? boolean_true_node
: boolean_false_node
;
3750 if (!usable_range_p (vr
, strict_overflow_p
))
3753 if (comp
== EQ_EXPR
)
3755 /* EQ_EXPR may only be computed if VR represents exactly
3757 if (compare_values_warnv (vr
->min
, vr
->max
, strict_overflow_p
) == 0)
3759 int cmp
= compare_values_warnv (vr
->min
, val
, strict_overflow_p
);
3761 return boolean_true_node
;
3762 else if (cmp
== -1 || cmp
== 1 || cmp
== 2)
3763 return boolean_false_node
;
3765 else if (compare_values_warnv (val
, vr
->min
, strict_overflow_p
) == -1
3766 || compare_values_warnv (vr
->max
, val
, strict_overflow_p
) == -1)
3767 return boolean_false_node
;
3771 else if (comp
== NE_EXPR
)
3773 /* If VAL is not inside VR, then they are always different. */
3774 if (compare_values_warnv (vr
->max
, val
, strict_overflow_p
) == -1
3775 || compare_values_warnv (vr
->min
, val
, strict_overflow_p
) == 1)
3776 return boolean_true_node
;
3778 /* If VR represents exactly one value equal to VAL, then return
3780 if (compare_values_warnv (vr
->min
, vr
->max
, strict_overflow_p
) == 0
3781 && compare_values_warnv (vr
->min
, val
, strict_overflow_p
) == 0)
3782 return boolean_false_node
;
3784 /* Otherwise, they may or may not be different. */
3787 else if (comp
== LT_EXPR
|| comp
== LE_EXPR
)
3791 /* If VR is to the left of VAL, return true. */
3792 tst
= compare_values_warnv (vr
->max
, val
, strict_overflow_p
);
3793 if ((comp
== LT_EXPR
&& tst
== -1)
3794 || (comp
== LE_EXPR
&& (tst
== -1 || tst
== 0)))
3796 if (overflow_infinity_range_p (vr
))
3797 *strict_overflow_p
= true;
3798 return boolean_true_node
;
3801 /* If VR is to the right of VAL, return false. */
3802 tst
= compare_values_warnv (vr
->min
, val
, strict_overflow_p
);
3803 if ((comp
== LT_EXPR
&& (tst
== 0 || tst
== 1))
3804 || (comp
== LE_EXPR
&& tst
== 1))
3806 if (overflow_infinity_range_p (vr
))
3807 *strict_overflow_p
= true;
3808 return boolean_false_node
;
3811 /* Otherwise, we don't know. */
3814 else if (comp
== GT_EXPR
|| comp
== GE_EXPR
)
3818 /* If VR is to the right of VAL, return true. */
3819 tst
= compare_values_warnv (vr
->min
, val
, strict_overflow_p
);
3820 if ((comp
== GT_EXPR
&& tst
== 1)
3821 || (comp
== GE_EXPR
&& (tst
== 0 || tst
== 1)))
3823 if (overflow_infinity_range_p (vr
))
3824 *strict_overflow_p
= true;
3825 return boolean_true_node
;
3828 /* If VR is to the left of VAL, return false. */
3829 tst
= compare_values_warnv (vr
->max
, val
, strict_overflow_p
);
3830 if ((comp
== GT_EXPR
&& (tst
== -1 || tst
== 0))
3831 || (comp
== GE_EXPR
&& tst
== -1))
3833 if (overflow_infinity_range_p (vr
))
3834 *strict_overflow_p
= true;
3835 return boolean_false_node
;
3838 /* Otherwise, we don't know. */
3846 /* Debugging dumps. */
3848 void dump_value_range (FILE *, value_range_t
*);
3849 void debug_value_range (value_range_t
*);
3850 void dump_all_value_ranges (FILE *);
3851 void debug_all_value_ranges (void);
3852 void dump_vr_equiv (FILE *, bitmap
);
3853 void debug_vr_equiv (bitmap
);
3856 /* Dump value range VR to FILE. */
3859 dump_value_range (FILE *file
, value_range_t
*vr
)
3862 fprintf (file
, "[]");
3863 else if (vr
->type
== VR_UNDEFINED
)
3864 fprintf (file
, "UNDEFINED");
3865 else if (vr
->type
== VR_RANGE
|| vr
->type
== VR_ANTI_RANGE
)
3867 tree type
= TREE_TYPE (vr
->min
);
3869 fprintf (file
, "%s[", (vr
->type
== VR_ANTI_RANGE
) ? "~" : "");
3871 if (is_negative_overflow_infinity (vr
->min
))
3872 fprintf (file
, "-INF(OVF)");
3873 else if (INTEGRAL_TYPE_P (type
)
3874 && !TYPE_UNSIGNED (type
)
3875 && vrp_val_is_min (vr
->min
))
3876 fprintf (file
, "-INF");
3878 print_generic_expr (file
, vr
->min
, 0);
3880 fprintf (file
, ", ");
3882 if (is_positive_overflow_infinity (vr
->max
))
3883 fprintf (file
, "+INF(OVF)");
3884 else if (INTEGRAL_TYPE_P (type
)
3885 && vrp_val_is_max (vr
->max
))
3886 fprintf (file
, "+INF");
3888 print_generic_expr (file
, vr
->max
, 0);
3890 fprintf (file
, "]");
3897 fprintf (file
, " EQUIVALENCES: { ");
3899 EXECUTE_IF_SET_IN_BITMAP (vr
->equiv
, 0, i
, bi
)
3901 print_generic_expr (file
, ssa_name (i
), 0);
3902 fprintf (file
, " ");
3906 fprintf (file
, "} (%u elements)", c
);
3909 else if (vr
->type
== VR_VARYING
)
3910 fprintf (file
, "VARYING");
3912 fprintf (file
, "INVALID RANGE");
3916 /* Dump value range VR to stderr. */
3919 debug_value_range (value_range_t
*vr
)
3921 dump_value_range (stderr
, vr
);
3922 fprintf (stderr
, "\n");
3926 /* Dump value ranges of all SSA_NAMEs to FILE. */
3929 dump_all_value_ranges (FILE *file
)
3933 for (i
= 0; i
< num_ssa_names
; i
++)
3937 print_generic_expr (file
, ssa_name (i
), 0);
3938 fprintf (file
, ": ");
3939 dump_value_range (file
, vr_value
[i
]);
3940 fprintf (file
, "\n");
3944 fprintf (file
, "\n");
3948 /* Dump all value ranges to stderr. */
3951 debug_all_value_ranges (void)
3953 dump_all_value_ranges (stderr
);
3957 /* Given a COND_EXPR COND of the form 'V OP W', and an SSA name V,
3958 create a new SSA name N and return the assertion assignment
3959 'V = ASSERT_EXPR <V, V OP W>'. */
3962 build_assert_expr_for (tree cond
, tree v
)
3967 gcc_assert (TREE_CODE (v
) == SSA_NAME
);
3968 n
= duplicate_ssa_name (v
, NULL
);
3970 if (COMPARISON_CLASS_P (cond
))
3972 tree a
= build2 (ASSERT_EXPR
, TREE_TYPE (v
), v
, cond
);
3973 assertion
= gimple_build_assign (n
, a
);
3975 else if (TREE_CODE (cond
) == TRUTH_NOT_EXPR
)
3977 /* Given !V, build the assignment N = false. */
3978 tree op0
= TREE_OPERAND (cond
, 0);
3979 gcc_assert (op0
== v
);
3980 assertion
= gimple_build_assign (n
, boolean_false_node
);
3982 else if (TREE_CODE (cond
) == SSA_NAME
)
3984 /* Given V, build the assignment N = true. */
3985 gcc_assert (v
== cond
);
3986 assertion
= gimple_build_assign (n
, boolean_true_node
);
3991 SSA_NAME_DEF_STMT (n
) = assertion
;
3993 /* The new ASSERT_EXPR, creates a new SSA name that replaces the
3994 operand of the ASSERT_EXPR. Register the new name and the old one
3995 in the replacement table so that we can fix the SSA web after
3996 adding all the ASSERT_EXPRs. */
3997 register_new_name_mapping (n
, v
);
4003 /* Return false if EXPR is a predicate expression involving floating
4007 fp_predicate (gimple stmt
)
4009 GIMPLE_CHECK (stmt
, GIMPLE_COND
);
4011 return FLOAT_TYPE_P (TREE_TYPE (gimple_cond_lhs (stmt
)));
4015 /* If the range of values taken by OP can be inferred after STMT executes,
4016 return the comparison code (COMP_CODE_P) and value (VAL_P) that
4017 describes the inferred range. Return true if a range could be
4021 infer_value_range (gimple stmt
, tree op
, enum tree_code
*comp_code_p
, tree
*val_p
)
4024 *comp_code_p
= ERROR_MARK
;
4026 /* Do not attempt to infer anything in names that flow through
4028 if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (op
))
4031 /* Similarly, don't infer anything from statements that may throw
4033 if (stmt_could_throw_p (stmt
))
4036 /* If STMT is the last statement of a basic block with no
4037 successors, there is no point inferring anything about any of its
4038 operands. We would not be able to find a proper insertion point
4039 for the assertion, anyway. */
4040 if (stmt_ends_bb_p (stmt
) && EDGE_COUNT (gimple_bb (stmt
)->succs
) == 0)
4043 /* We can only assume that a pointer dereference will yield
4044 non-NULL if -fdelete-null-pointer-checks is enabled. */
4045 if (flag_delete_null_pointer_checks
4046 && POINTER_TYPE_P (TREE_TYPE (op
))
4047 && gimple_code (stmt
) != GIMPLE_ASM
)
4049 unsigned num_uses
, num_loads
, num_stores
;
4051 count_uses_and_derefs (op
, stmt
, &num_uses
, &num_loads
, &num_stores
);
4052 if (num_loads
+ num_stores
> 0)
4054 *val_p
= build_int_cst (TREE_TYPE (op
), 0);
4055 *comp_code_p
= NE_EXPR
;
4064 void dump_asserts_for (FILE *, tree
);
4065 void debug_asserts_for (tree
);
4066 void dump_all_asserts (FILE *);
4067 void debug_all_asserts (void);
4069 /* Dump all the registered assertions for NAME to FILE. */
4072 dump_asserts_for (FILE *file
, tree name
)
4076 fprintf (file
, "Assertions to be inserted for ");
4077 print_generic_expr (file
, name
, 0);
4078 fprintf (file
, "\n");
4080 loc
= asserts_for
[SSA_NAME_VERSION (name
)];
4083 fprintf (file
, "\t");
4084 print_gimple_stmt (file
, gsi_stmt (loc
->si
), 0, 0);
4085 fprintf (file
, "\n\tBB #%d", loc
->bb
->index
);
4088 fprintf (file
, "\n\tEDGE %d->%d", loc
->e
->src
->index
,
4089 loc
->e
->dest
->index
);
4090 dump_edge_info (file
, loc
->e
, 0);
4092 fprintf (file
, "\n\tPREDICATE: ");
4093 print_generic_expr (file
, name
, 0);
4094 fprintf (file
, " %s ", tree_code_name
[(int)loc
->comp_code
]);
4095 print_generic_expr (file
, loc
->val
, 0);
4096 fprintf (file
, "\n\n");
4100 fprintf (file
, "\n");
4104 /* Dump all the registered assertions for NAME to stderr. */
4107 debug_asserts_for (tree name
)
4109 dump_asserts_for (stderr
, name
);
4113 /* Dump all the registered assertions for all the names to FILE. */
4116 dump_all_asserts (FILE *file
)
4121 fprintf (file
, "\nASSERT_EXPRs to be inserted\n\n");
4122 EXECUTE_IF_SET_IN_BITMAP (need_assert_for
, 0, i
, bi
)
4123 dump_asserts_for (file
, ssa_name (i
));
4124 fprintf (file
, "\n");
4128 /* Dump all the registered assertions for all the names to stderr. */
4131 debug_all_asserts (void)
4133 dump_all_asserts (stderr
);
4137 /* If NAME doesn't have an ASSERT_EXPR registered for asserting
4138 'EXPR COMP_CODE VAL' at a location that dominates block BB or
4139 E->DEST, then register this location as a possible insertion point
4140 for ASSERT_EXPR <NAME, EXPR COMP_CODE VAL>.
4142 BB, E and SI provide the exact insertion point for the new
4143 ASSERT_EXPR. If BB is NULL, then the ASSERT_EXPR is to be inserted
4144 on edge E. Otherwise, if E is NULL, the ASSERT_EXPR is inserted on
4145 BB. If SI points to a COND_EXPR or a SWITCH_EXPR statement, then E
4146 must not be NULL. */
4149 register_new_assert_for (tree name
, tree expr
,
4150 enum tree_code comp_code
,
4154 gimple_stmt_iterator si
)
4156 assert_locus_t n
, loc
, last_loc
;
4157 basic_block dest_bb
;
4159 gcc_checking_assert (bb
== NULL
|| e
== NULL
);
4162 gcc_checking_assert (gimple_code (gsi_stmt (si
)) != GIMPLE_COND
4163 && gimple_code (gsi_stmt (si
)) != GIMPLE_SWITCH
);
4165 /* Never build an assert comparing against an integer constant with
4166 TREE_OVERFLOW set. This confuses our undefined overflow warning
4168 if (TREE_CODE (val
) == INTEGER_CST
4169 && TREE_OVERFLOW (val
))
4170 val
= build_int_cst_wide (TREE_TYPE (val
),
4171 TREE_INT_CST_LOW (val
), TREE_INT_CST_HIGH (val
));
4173 /* The new assertion A will be inserted at BB or E. We need to
4174 determine if the new location is dominated by a previously
4175 registered location for A. If we are doing an edge insertion,
4176 assume that A will be inserted at E->DEST. Note that this is not
4179 If E is a critical edge, it will be split. But even if E is
4180 split, the new block will dominate the same set of blocks that
4183 The reverse, however, is not true, blocks dominated by E->DEST
4184 will not be dominated by the new block created to split E. So,
4185 if the insertion location is on a critical edge, we will not use
4186 the new location to move another assertion previously registered
4187 at a block dominated by E->DEST. */
4188 dest_bb
= (bb
) ? bb
: e
->dest
;
4190 /* If NAME already has an ASSERT_EXPR registered for COMP_CODE and
4191 VAL at a block dominating DEST_BB, then we don't need to insert a new
4192 one. Similarly, if the same assertion already exists at a block
4193 dominated by DEST_BB and the new location is not on a critical
4194 edge, then update the existing location for the assertion (i.e.,
4195 move the assertion up in the dominance tree).
4197 Note, this is implemented as a simple linked list because there
4198 should not be more than a handful of assertions registered per
4199 name. If this becomes a performance problem, a table hashed by
4200 COMP_CODE and VAL could be implemented. */
4201 loc
= asserts_for
[SSA_NAME_VERSION (name
)];
4205 if (loc
->comp_code
== comp_code
4207 || operand_equal_p (loc
->val
, val
, 0))
4208 && (loc
->expr
== expr
4209 || operand_equal_p (loc
->expr
, expr
, 0)))
4211 /* If the assertion NAME COMP_CODE VAL has already been
4212 registered at a basic block that dominates DEST_BB, then
4213 we don't need to insert the same assertion again. Note
4214 that we don't check strict dominance here to avoid
4215 replicating the same assertion inside the same basic
4216 block more than once (e.g., when a pointer is
4217 dereferenced several times inside a block).
4219 An exception to this rule are edge insertions. If the
4220 new assertion is to be inserted on edge E, then it will
4221 dominate all the other insertions that we may want to
4222 insert in DEST_BB. So, if we are doing an edge
4223 insertion, don't do this dominance check. */
4225 && dominated_by_p (CDI_DOMINATORS
, dest_bb
, loc
->bb
))
4228 /* Otherwise, if E is not a critical edge and DEST_BB
4229 dominates the existing location for the assertion, move
4230 the assertion up in the dominance tree by updating its
4231 location information. */
4232 if ((e
== NULL
|| !EDGE_CRITICAL_P (e
))
4233 && dominated_by_p (CDI_DOMINATORS
, loc
->bb
, dest_bb
))
4242 /* Update the last node of the list and move to the next one. */
4247 /* If we didn't find an assertion already registered for
4248 NAME COMP_CODE VAL, add a new one at the end of the list of
4249 assertions associated with NAME. */
4250 n
= XNEW (struct assert_locus_d
);
4254 n
->comp_code
= comp_code
;
4262 asserts_for
[SSA_NAME_VERSION (name
)] = n
;
4264 bitmap_set_bit (need_assert_for
, SSA_NAME_VERSION (name
));
4267 /* (COND_OP0 COND_CODE COND_OP1) is a predicate which uses NAME.
4268 Extract a suitable test code and value and store them into *CODE_P and
4269 *VAL_P so the predicate is normalized to NAME *CODE_P *VAL_P.
4271 If no extraction was possible, return FALSE, otherwise return TRUE.
4273 If INVERT is true, then we invert the result stored into *CODE_P. */
4276 extract_code_and_val_from_cond_with_ops (tree name
, enum tree_code cond_code
,
4277 tree cond_op0
, tree cond_op1
,
4278 bool invert
, enum tree_code
*code_p
,
4281 enum tree_code comp_code
;
4284 /* Otherwise, we have a comparison of the form NAME COMP VAL
4285 or VAL COMP NAME. */
4286 if (name
== cond_op1
)
4288 /* If the predicate is of the form VAL COMP NAME, flip
4289 COMP around because we need to register NAME as the
4290 first operand in the predicate. */
4291 comp_code
= swap_tree_comparison (cond_code
);
4296 /* The comparison is of the form NAME COMP VAL, so the
4297 comparison code remains unchanged. */
4298 comp_code
= cond_code
;
4302 /* Invert the comparison code as necessary. */
4304 comp_code
= invert_tree_comparison (comp_code
, 0);
4306 /* VRP does not handle float types. */
4307 if (SCALAR_FLOAT_TYPE_P (TREE_TYPE (val
)))
4310 /* Do not register always-false predicates.
4311 FIXME: this works around a limitation in fold() when dealing with
4312 enumerations. Given 'enum { N1, N2 } x;', fold will not
4313 fold 'if (x > N2)' to 'if (0)'. */
4314 if ((comp_code
== GT_EXPR
|| comp_code
== LT_EXPR
)
4315 && INTEGRAL_TYPE_P (TREE_TYPE (val
)))
4317 tree min
= TYPE_MIN_VALUE (TREE_TYPE (val
));
4318 tree max
= TYPE_MAX_VALUE (TREE_TYPE (val
));
4320 if (comp_code
== GT_EXPR
4322 || compare_values (val
, max
) == 0))
4325 if (comp_code
== LT_EXPR
4327 || compare_values (val
, min
) == 0))
4330 *code_p
= comp_code
;
4335 /* Try to register an edge assertion for SSA name NAME on edge E for
4336 the condition COND contributing to the conditional jump pointed to by BSI.
4337 Invert the condition COND if INVERT is true.
4338 Return true if an assertion for NAME could be registered. */
4341 register_edge_assert_for_2 (tree name
, edge e
, gimple_stmt_iterator bsi
,
4342 enum tree_code cond_code
,
4343 tree cond_op0
, tree cond_op1
, bool invert
)
4346 enum tree_code comp_code
;
4347 bool retval
= false;
4349 if (!extract_code_and_val_from_cond_with_ops (name
, cond_code
,
4352 invert
, &comp_code
, &val
))
4355 /* Only register an ASSERT_EXPR if NAME was found in the sub-graph
4356 reachable from E. */
4357 if (live_on_edge (e
, name
)
4358 && !has_single_use (name
))
4360 register_new_assert_for (name
, name
, comp_code
, val
, NULL
, e
, bsi
);
4364 /* In the case of NAME <= CST and NAME being defined as
4365 NAME = (unsigned) NAME2 + CST2 we can assert NAME2 >= -CST2
4366 and NAME2 <= CST - CST2. We can do the same for NAME > CST.
4367 This catches range and anti-range tests. */
4368 if ((comp_code
== LE_EXPR
4369 || comp_code
== GT_EXPR
)
4370 && TREE_CODE (val
) == INTEGER_CST
4371 && TYPE_UNSIGNED (TREE_TYPE (val
)))
4373 gimple def_stmt
= SSA_NAME_DEF_STMT (name
);
4374 tree cst2
= NULL_TREE
, name2
= NULL_TREE
, name3
= NULL_TREE
;
4376 /* Extract CST2 from the (optional) addition. */
4377 if (is_gimple_assign (def_stmt
)
4378 && gimple_assign_rhs_code (def_stmt
) == PLUS_EXPR
)
4380 name2
= gimple_assign_rhs1 (def_stmt
);
4381 cst2
= gimple_assign_rhs2 (def_stmt
);
4382 if (TREE_CODE (name2
) == SSA_NAME
4383 && TREE_CODE (cst2
) == INTEGER_CST
)
4384 def_stmt
= SSA_NAME_DEF_STMT (name2
);
4387 /* Extract NAME2 from the (optional) sign-changing cast. */
4388 if (gimple_assign_cast_p (def_stmt
))
4390 if (CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (def_stmt
))
4391 && ! TYPE_UNSIGNED (TREE_TYPE (gimple_assign_rhs1 (def_stmt
)))
4392 && (TYPE_PRECISION (gimple_expr_type (def_stmt
))
4393 == TYPE_PRECISION (TREE_TYPE (gimple_assign_rhs1 (def_stmt
)))))
4394 name3
= gimple_assign_rhs1 (def_stmt
);
4397 /* If name3 is used later, create an ASSERT_EXPR for it. */
4398 if (name3
!= NULL_TREE
4399 && TREE_CODE (name3
) == SSA_NAME
4400 && (cst2
== NULL_TREE
4401 || TREE_CODE (cst2
) == INTEGER_CST
)
4402 && INTEGRAL_TYPE_P (TREE_TYPE (name3
))
4403 && live_on_edge (e
, name3
)
4404 && !has_single_use (name3
))
4408 /* Build an expression for the range test. */
4409 tmp
= build1 (NOP_EXPR
, TREE_TYPE (name
), name3
);
4410 if (cst2
!= NULL_TREE
)
4411 tmp
= build2 (PLUS_EXPR
, TREE_TYPE (name
), tmp
, cst2
);
4415 fprintf (dump_file
, "Adding assert for ");
4416 print_generic_expr (dump_file
, name3
, 0);
4417 fprintf (dump_file
, " from ");
4418 print_generic_expr (dump_file
, tmp
, 0);
4419 fprintf (dump_file
, "\n");
4422 register_new_assert_for (name3
, tmp
, comp_code
, val
, NULL
, e
, bsi
);
4427 /* If name2 is used later, create an ASSERT_EXPR for it. */
4428 if (name2
!= NULL_TREE
4429 && TREE_CODE (name2
) == SSA_NAME
4430 && TREE_CODE (cst2
) == INTEGER_CST
4431 && INTEGRAL_TYPE_P (TREE_TYPE (name2
))
4432 && live_on_edge (e
, name2
)
4433 && !has_single_use (name2
))
4437 /* Build an expression for the range test. */
4439 if (TREE_TYPE (name
) != TREE_TYPE (name2
))
4440 tmp
= build1 (NOP_EXPR
, TREE_TYPE (name
), tmp
);
4441 if (cst2
!= NULL_TREE
)
4442 tmp
= build2 (PLUS_EXPR
, TREE_TYPE (name
), tmp
, cst2
);
4446 fprintf (dump_file
, "Adding assert for ");
4447 print_generic_expr (dump_file
, name2
, 0);
4448 fprintf (dump_file
, " from ");
4449 print_generic_expr (dump_file
, tmp
, 0);
4450 fprintf (dump_file
, "\n");
4453 register_new_assert_for (name2
, tmp
, comp_code
, val
, NULL
, e
, bsi
);
4462 /* OP is an operand of a truth value expression which is known to have
4463 a particular value. Register any asserts for OP and for any
4464 operands in OP's defining statement.
4466 If CODE is EQ_EXPR, then we want to register OP is zero (false),
4467 if CODE is NE_EXPR, then we want to register OP is nonzero (true). */
4470 register_edge_assert_for_1 (tree op
, enum tree_code code
,
4471 edge e
, gimple_stmt_iterator bsi
)
4473 bool retval
= false;
4476 enum tree_code rhs_code
;
4478 /* We only care about SSA_NAMEs. */
4479 if (TREE_CODE (op
) != SSA_NAME
)
4482 /* We know that OP will have a zero or nonzero value. If OP is used
4483 more than once go ahead and register an assert for OP.
4485 The FOUND_IN_SUBGRAPH support is not helpful in this situation as
4486 it will always be set for OP (because OP is used in a COND_EXPR in
4488 if (!has_single_use (op
))
4490 val
= build_int_cst (TREE_TYPE (op
), 0);
4491 register_new_assert_for (op
, op
, code
, val
, NULL
, e
, bsi
);
4495 /* Now look at how OP is set. If it's set from a comparison,
4496 a truth operation or some bit operations, then we may be able
4497 to register information about the operands of that assignment. */
4498 op_def
= SSA_NAME_DEF_STMT (op
);
4499 if (gimple_code (op_def
) != GIMPLE_ASSIGN
)
4502 rhs_code
= gimple_assign_rhs_code (op_def
);
4504 if (TREE_CODE_CLASS (rhs_code
) == tcc_comparison
)
4506 bool invert
= (code
== EQ_EXPR
? true : false);
4507 tree op0
= gimple_assign_rhs1 (op_def
);
4508 tree op1
= gimple_assign_rhs2 (op_def
);
4510 if (TREE_CODE (op0
) == SSA_NAME
)
4511 retval
|= register_edge_assert_for_2 (op0
, e
, bsi
, rhs_code
, op0
, op1
,
4513 if (TREE_CODE (op1
) == SSA_NAME
)
4514 retval
|= register_edge_assert_for_2 (op1
, e
, bsi
, rhs_code
, op0
, op1
,
4517 else if ((code
== NE_EXPR
4518 && (gimple_assign_rhs_code (op_def
) == TRUTH_AND_EXPR
4519 || gimple_assign_rhs_code (op_def
) == BIT_AND_EXPR
))
4521 && (gimple_assign_rhs_code (op_def
) == TRUTH_OR_EXPR
4522 || gimple_assign_rhs_code (op_def
) == BIT_IOR_EXPR
)))
4524 /* Recurse on each operand. */
4525 retval
|= register_edge_assert_for_1 (gimple_assign_rhs1 (op_def
),
4527 retval
|= register_edge_assert_for_1 (gimple_assign_rhs2 (op_def
),
4530 else if (gimple_assign_rhs_code (op_def
) == TRUTH_NOT_EXPR
)
4532 /* Recurse, flipping CODE. */
4533 code
= invert_tree_comparison (code
, false);
4534 retval
|= register_edge_assert_for_1 (gimple_assign_rhs1 (op_def
),
4537 else if (gimple_assign_rhs_code (op_def
) == SSA_NAME
)
4539 /* Recurse through the copy. */
4540 retval
|= register_edge_assert_for_1 (gimple_assign_rhs1 (op_def
),
4543 else if (CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (op_def
)))
4545 /* Recurse through the type conversion. */
4546 retval
|= register_edge_assert_for_1 (gimple_assign_rhs1 (op_def
),
4553 /* Try to register an edge assertion for SSA name NAME on edge E for
4554 the condition COND contributing to the conditional jump pointed to by SI.
4555 Return true if an assertion for NAME could be registered. */
4558 register_edge_assert_for (tree name
, edge e
, gimple_stmt_iterator si
,
4559 enum tree_code cond_code
, tree cond_op0
,
4563 enum tree_code comp_code
;
4564 bool retval
= false;
4565 bool is_else_edge
= (e
->flags
& EDGE_FALSE_VALUE
) != 0;
4567 /* Do not attempt to infer anything in names that flow through
4569 if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (name
))
4572 if (!extract_code_and_val_from_cond_with_ops (name
, cond_code
,
4578 /* Register ASSERT_EXPRs for name. */
4579 retval
|= register_edge_assert_for_2 (name
, e
, si
, cond_code
, cond_op0
,
4580 cond_op1
, is_else_edge
);
4583 /* If COND is effectively an equality test of an SSA_NAME against
4584 the value zero or one, then we may be able to assert values
4585 for SSA_NAMEs which flow into COND. */
4587 /* In the case of NAME == 1 or NAME != 0, for TRUTH_AND_EXPR defining
4588 statement of NAME we can assert both operands of the TRUTH_AND_EXPR
4589 have nonzero value. */
4590 if (((comp_code
== EQ_EXPR
&& integer_onep (val
))
4591 || (comp_code
== NE_EXPR
&& integer_zerop (val
))))
4593 gimple def_stmt
= SSA_NAME_DEF_STMT (name
);
4595 if (is_gimple_assign (def_stmt
)
4596 && (gimple_assign_rhs_code (def_stmt
) == TRUTH_AND_EXPR
4597 || gimple_assign_rhs_code (def_stmt
) == BIT_AND_EXPR
))
4599 tree op0
= gimple_assign_rhs1 (def_stmt
);
4600 tree op1
= gimple_assign_rhs2 (def_stmt
);
4601 retval
|= register_edge_assert_for_1 (op0
, NE_EXPR
, e
, si
);
4602 retval
|= register_edge_assert_for_1 (op1
, NE_EXPR
, e
, si
);
4606 /* In the case of NAME == 0 or NAME != 1, for TRUTH_OR_EXPR defining
4607 statement of NAME we can assert both operands of the TRUTH_OR_EXPR
4609 if (((comp_code
== EQ_EXPR
&& integer_zerop (val
))
4610 || (comp_code
== NE_EXPR
&& integer_onep (val
))))
4612 gimple def_stmt
= SSA_NAME_DEF_STMT (name
);
4614 if (is_gimple_assign (def_stmt
)
4615 && (gimple_assign_rhs_code (def_stmt
) == TRUTH_OR_EXPR
4616 /* For BIT_IOR_EXPR only if NAME == 0 both operands have
4617 necessarily zero value. */
4618 || (comp_code
== EQ_EXPR
4619 && (gimple_assign_rhs_code (def_stmt
) == BIT_IOR_EXPR
))))
4621 tree op0
= gimple_assign_rhs1 (def_stmt
);
4622 tree op1
= gimple_assign_rhs2 (def_stmt
);
4623 retval
|= register_edge_assert_for_1 (op0
, EQ_EXPR
, e
, si
);
4624 retval
|= register_edge_assert_for_1 (op1
, EQ_EXPR
, e
, si
);
4632 /* Determine whether the outgoing edges of BB should receive an
4633 ASSERT_EXPR for each of the operands of BB's LAST statement.
4634 The last statement of BB must be a COND_EXPR.
4636 If any of the sub-graphs rooted at BB have an interesting use of
4637 the predicate operands, an assert location node is added to the
4638 list of assertions for the corresponding operands. */
4641 find_conditional_asserts (basic_block bb
, gimple last
)
4644 gimple_stmt_iterator bsi
;
4650 need_assert
= false;
4651 bsi
= gsi_for_stmt (last
);
4653 /* Look for uses of the operands in each of the sub-graphs
4654 rooted at BB. We need to check each of the outgoing edges
4655 separately, so that we know what kind of ASSERT_EXPR to
4657 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
4662 /* Register the necessary assertions for each operand in the
4663 conditional predicate. */
4664 FOR_EACH_SSA_TREE_OPERAND (op
, last
, iter
, SSA_OP_USE
)
4666 need_assert
|= register_edge_assert_for (op
, e
, bsi
,
4667 gimple_cond_code (last
),
4668 gimple_cond_lhs (last
),
4669 gimple_cond_rhs (last
));
4682 /* Compare two case labels sorting first by the destination bb index
4683 and then by the case value. */
4686 compare_case_labels (const void *p1
, const void *p2
)
4688 const struct case_info
*ci1
= (const struct case_info
*) p1
;
4689 const struct case_info
*ci2
= (const struct case_info
*) p2
;
4690 int idx1
= ci1
->bb
->index
;
4691 int idx2
= ci2
->bb
->index
;
4695 else if (idx1
== idx2
)
4697 /* Make sure the default label is first in a group. */
4698 if (!CASE_LOW (ci1
->expr
))
4700 else if (!CASE_LOW (ci2
->expr
))
4703 return tree_int_cst_compare (CASE_LOW (ci1
->expr
),
4704 CASE_LOW (ci2
->expr
));
4710 /* Determine whether the outgoing edges of BB should receive an
4711 ASSERT_EXPR for each of the operands of BB's LAST statement.
4712 The last statement of BB must be a SWITCH_EXPR.
4714 If any of the sub-graphs rooted at BB have an interesting use of
4715 the predicate operands, an assert location node is added to the
4716 list of assertions for the corresponding operands. */
4719 find_switch_asserts (basic_block bb
, gimple last
)
4722 gimple_stmt_iterator bsi
;
4725 struct case_info
*ci
;
4726 size_t n
= gimple_switch_num_labels (last
);
4727 #if GCC_VERSION >= 4000
4730 /* Work around GCC 3.4 bug (PR 37086). */
4731 volatile unsigned int idx
;
4734 need_assert
= false;
4735 bsi
= gsi_for_stmt (last
);
4736 op
= gimple_switch_index (last
);
4737 if (TREE_CODE (op
) != SSA_NAME
)
4740 /* Build a vector of case labels sorted by destination label. */
4741 ci
= XNEWVEC (struct case_info
, n
);
4742 for (idx
= 0; idx
< n
; ++idx
)
4744 ci
[idx
].expr
= gimple_switch_label (last
, idx
);
4745 ci
[idx
].bb
= label_to_block (CASE_LABEL (ci
[idx
].expr
));
4747 qsort (ci
, n
, sizeof (struct case_info
), compare_case_labels
);
4749 for (idx
= 0; idx
< n
; ++idx
)
4752 tree cl
= ci
[idx
].expr
;
4753 basic_block cbb
= ci
[idx
].bb
;
4755 min
= CASE_LOW (cl
);
4756 max
= CASE_HIGH (cl
);
4758 /* If there are multiple case labels with the same destination
4759 we need to combine them to a single value range for the edge. */
4760 if (idx
+ 1 < n
&& cbb
== ci
[idx
+ 1].bb
)
4762 /* Skip labels until the last of the group. */
4765 } while (idx
< n
&& cbb
== ci
[idx
].bb
);
4768 /* Pick up the maximum of the case label range. */
4769 if (CASE_HIGH (ci
[idx
].expr
))
4770 max
= CASE_HIGH (ci
[idx
].expr
);
4772 max
= CASE_LOW (ci
[idx
].expr
);
4775 /* Nothing to do if the range includes the default label until we
4776 can register anti-ranges. */
4777 if (min
== NULL_TREE
)
4780 /* Find the edge to register the assert expr on. */
4781 e
= find_edge (bb
, cbb
);
4783 /* Register the necessary assertions for the operand in the
4785 need_assert
|= register_edge_assert_for (op
, e
, bsi
,
4786 max
? GE_EXPR
: EQ_EXPR
,
4788 fold_convert (TREE_TYPE (op
),
4792 need_assert
|= register_edge_assert_for (op
, e
, bsi
, LE_EXPR
,
4794 fold_convert (TREE_TYPE (op
),
4804 /* Traverse all the statements in block BB looking for statements that
4805 may generate useful assertions for the SSA names in their operand.
4806 If a statement produces a useful assertion A for name N_i, then the
4807 list of assertions already generated for N_i is scanned to
4808 determine if A is actually needed.
4810 If N_i already had the assertion A at a location dominating the
4811 current location, then nothing needs to be done. Otherwise, the
4812 new location for A is recorded instead.
4814 1- For every statement S in BB, all the variables used by S are
4815 added to bitmap FOUND_IN_SUBGRAPH.
4817 2- If statement S uses an operand N in a way that exposes a known
4818 value range for N, then if N was not already generated by an
4819 ASSERT_EXPR, create a new assert location for N. For instance,
4820 if N is a pointer and the statement dereferences it, we can
4821 assume that N is not NULL.
4823 3- COND_EXPRs are a special case of #2. We can derive range
4824 information from the predicate but need to insert different
4825 ASSERT_EXPRs for each of the sub-graphs rooted at the
4826 conditional block. If the last statement of BB is a conditional
4827 expression of the form 'X op Y', then
4829 a) Remove X and Y from the set FOUND_IN_SUBGRAPH.
4831 b) If the conditional is the only entry point to the sub-graph
4832 corresponding to the THEN_CLAUSE, recurse into it. On
4833 return, if X and/or Y are marked in FOUND_IN_SUBGRAPH, then
4834 an ASSERT_EXPR is added for the corresponding variable.
4836 c) Repeat step (b) on the ELSE_CLAUSE.
4838 d) Mark X and Y in FOUND_IN_SUBGRAPH.
4847 In this case, an assertion on the THEN clause is useful to
4848 determine that 'a' is always 9 on that edge. However, an assertion
4849 on the ELSE clause would be unnecessary.
4851 4- If BB does not end in a conditional expression, then we recurse
4852 into BB's dominator children.
4854 At the end of the recursive traversal, every SSA name will have a
4855 list of locations where ASSERT_EXPRs should be added. When a new
4856 location for name N is found, it is registered by calling
4857 register_new_assert_for. That function keeps track of all the
4858 registered assertions to prevent adding unnecessary assertions.
4859 For instance, if a pointer P_4 is dereferenced more than once in a
4860 dominator tree, only the location dominating all the dereference of
4861 P_4 will receive an ASSERT_EXPR.
4863 If this function returns true, then it means that there are names
4864 for which we need to generate ASSERT_EXPRs. Those assertions are
4865 inserted by process_assert_insertions. */
4868 find_assert_locations_1 (basic_block bb
, sbitmap live
)
4870 gimple_stmt_iterator si
;
4875 need_assert
= false;
4876 last
= last_stmt (bb
);
4878 /* If BB's last statement is a conditional statement involving integer
4879 operands, determine if we need to add ASSERT_EXPRs. */
4881 && gimple_code (last
) == GIMPLE_COND
4882 && !fp_predicate (last
)
4883 && !ZERO_SSA_OPERANDS (last
, SSA_OP_USE
))
4884 need_assert
|= find_conditional_asserts (bb
, last
);
4886 /* If BB's last statement is a switch statement involving integer
4887 operands, determine if we need to add ASSERT_EXPRs. */
4889 && gimple_code (last
) == GIMPLE_SWITCH
4890 && !ZERO_SSA_OPERANDS (last
, SSA_OP_USE
))
4891 need_assert
|= find_switch_asserts (bb
, last
);
4893 /* Traverse all the statements in BB marking used names and looking
4894 for statements that may infer assertions for their used operands. */
4895 for (si
= gsi_start_bb (bb
); !gsi_end_p (si
); gsi_next (&si
))
4901 stmt
= gsi_stmt (si
);
4903 if (is_gimple_debug (stmt
))
4906 /* See if we can derive an assertion for any of STMT's operands. */
4907 FOR_EACH_SSA_TREE_OPERAND (op
, stmt
, i
, SSA_OP_USE
)
4910 enum tree_code comp_code
;
4912 /* Mark OP in our live bitmap. */
4913 SET_BIT (live
, SSA_NAME_VERSION (op
));
4915 /* If OP is used in such a way that we can infer a value
4916 range for it, and we don't find a previous assertion for
4917 it, create a new assertion location node for OP. */
4918 if (infer_value_range (stmt
, op
, &comp_code
, &value
))
4920 /* If we are able to infer a nonzero value range for OP,
4921 then walk backwards through the use-def chain to see if OP
4922 was set via a typecast.
4924 If so, then we can also infer a nonzero value range
4925 for the operand of the NOP_EXPR. */
4926 if (comp_code
== NE_EXPR
&& integer_zerop (value
))
4929 gimple def_stmt
= SSA_NAME_DEF_STMT (t
);
4931 while (is_gimple_assign (def_stmt
)
4932 && gimple_assign_rhs_code (def_stmt
) == NOP_EXPR
4934 (gimple_assign_rhs1 (def_stmt
)) == SSA_NAME
4936 (TREE_TYPE (gimple_assign_rhs1 (def_stmt
))))
4938 t
= gimple_assign_rhs1 (def_stmt
);
4939 def_stmt
= SSA_NAME_DEF_STMT (t
);
4941 /* Note we want to register the assert for the
4942 operand of the NOP_EXPR after SI, not after the
4944 if (! has_single_use (t
))
4946 register_new_assert_for (t
, t
, comp_code
, value
,
4953 /* If OP is used only once, namely in this STMT, don't
4954 bother creating an ASSERT_EXPR for it. Such an
4955 ASSERT_EXPR would do nothing but increase compile time. */
4956 if (!has_single_use (op
))
4958 register_new_assert_for (op
, op
, comp_code
, value
,
4966 /* Traverse all PHI nodes in BB marking used operands. */
4967 for (si
= gsi_start_phis (bb
); !gsi_end_p(si
); gsi_next (&si
))
4969 use_operand_p arg_p
;
4971 phi
= gsi_stmt (si
);
4973 FOR_EACH_PHI_ARG (arg_p
, phi
, i
, SSA_OP_USE
)
4975 tree arg
= USE_FROM_PTR (arg_p
);
4976 if (TREE_CODE (arg
) == SSA_NAME
)
4977 SET_BIT (live
, SSA_NAME_VERSION (arg
));
4984 /* Do an RPO walk over the function computing SSA name liveness
4985 on-the-fly and deciding on assert expressions to insert.
4986 Returns true if there are assert expressions to be inserted. */
4989 find_assert_locations (void)
4991 int *rpo
= XCNEWVEC (int, last_basic_block
+ NUM_FIXED_BLOCKS
);
4992 int *bb_rpo
= XCNEWVEC (int, last_basic_block
+ NUM_FIXED_BLOCKS
);
4993 int *last_rpo
= XCNEWVEC (int, last_basic_block
+ NUM_FIXED_BLOCKS
);
4997 live
= XCNEWVEC (sbitmap
, last_basic_block
+ NUM_FIXED_BLOCKS
);
4998 rpo_cnt
= pre_and_rev_post_order_compute (NULL
, rpo
, false);
4999 for (i
= 0; i
< rpo_cnt
; ++i
)
5002 need_asserts
= false;
5003 for (i
= rpo_cnt
-1; i
>= 0; --i
)
5005 basic_block bb
= BASIC_BLOCK (rpo
[i
]);
5011 live
[rpo
[i
]] = sbitmap_alloc (num_ssa_names
);
5012 sbitmap_zero (live
[rpo
[i
]]);
5015 /* Process BB and update the live information with uses in
5017 need_asserts
|= find_assert_locations_1 (bb
, live
[rpo
[i
]]);
5019 /* Merge liveness into the predecessor blocks and free it. */
5020 if (!sbitmap_empty_p (live
[rpo
[i
]]))
5023 FOR_EACH_EDGE (e
, ei
, bb
->preds
)
5025 int pred
= e
->src
->index
;
5026 if (e
->flags
& EDGE_DFS_BACK
)
5031 live
[pred
] = sbitmap_alloc (num_ssa_names
);
5032 sbitmap_zero (live
[pred
]);
5034 sbitmap_a_or_b (live
[pred
], live
[pred
], live
[rpo
[i
]]);
5036 if (bb_rpo
[pred
] < pred_rpo
)
5037 pred_rpo
= bb_rpo
[pred
];
5040 /* Record the RPO number of the last visited block that needs
5041 live information from this block. */
5042 last_rpo
[rpo
[i
]] = pred_rpo
;
5046 sbitmap_free (live
[rpo
[i
]]);
5047 live
[rpo
[i
]] = NULL
;
5050 /* We can free all successors live bitmaps if all their
5051 predecessors have been visited already. */
5052 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
5053 if (last_rpo
[e
->dest
->index
] == i
5054 && live
[e
->dest
->index
])
5056 sbitmap_free (live
[e
->dest
->index
]);
5057 live
[e
->dest
->index
] = NULL
;
5062 XDELETEVEC (bb_rpo
);
5063 XDELETEVEC (last_rpo
);
5064 for (i
= 0; i
< last_basic_block
+ NUM_FIXED_BLOCKS
; ++i
)
5066 sbitmap_free (live
[i
]);
5069 return need_asserts
;
5072 /* Create an ASSERT_EXPR for NAME and insert it in the location
5073 indicated by LOC. Return true if we made any edge insertions. */
5076 process_assert_insertions_for (tree name
, assert_locus_t loc
)
5078 /* Build the comparison expression NAME_i COMP_CODE VAL. */
5085 /* If we have X <=> X do not insert an assert expr for that. */
5086 if (loc
->expr
== loc
->val
)
5089 cond
= build2 (loc
->comp_code
, boolean_type_node
, loc
->expr
, loc
->val
);
5090 assert_stmt
= build_assert_expr_for (cond
, name
);
5093 /* We have been asked to insert the assertion on an edge. This
5094 is used only by COND_EXPR and SWITCH_EXPR assertions. */
5095 gcc_checking_assert (gimple_code (gsi_stmt (loc
->si
)) == GIMPLE_COND
5096 || (gimple_code (gsi_stmt (loc
->si
))
5099 gsi_insert_on_edge (loc
->e
, assert_stmt
);
5103 /* Otherwise, we can insert right after LOC->SI iff the
5104 statement must not be the last statement in the block. */
5105 stmt
= gsi_stmt (loc
->si
);
5106 if (!stmt_ends_bb_p (stmt
))
5108 gsi_insert_after (&loc
->si
, assert_stmt
, GSI_SAME_STMT
);
5112 /* If STMT must be the last statement in BB, we can only insert new
5113 assertions on the non-abnormal edge out of BB. Note that since
5114 STMT is not control flow, there may only be one non-abnormal edge
5116 FOR_EACH_EDGE (e
, ei
, loc
->bb
->succs
)
5117 if (!(e
->flags
& EDGE_ABNORMAL
))
5119 gsi_insert_on_edge (e
, assert_stmt
);
5127 /* Process all the insertions registered for every name N_i registered
5128 in NEED_ASSERT_FOR. The list of assertions to be inserted are
5129 found in ASSERTS_FOR[i]. */
5132 process_assert_insertions (void)
5136 bool update_edges_p
= false;
5137 int num_asserts
= 0;
5139 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
5140 dump_all_asserts (dump_file
);
5142 EXECUTE_IF_SET_IN_BITMAP (need_assert_for
, 0, i
, bi
)
5144 assert_locus_t loc
= asserts_for
[i
];
5149 assert_locus_t next
= loc
->next
;
5150 update_edges_p
|= process_assert_insertions_for (ssa_name (i
), loc
);
5158 gsi_commit_edge_inserts ();
5160 statistics_counter_event (cfun
, "Number of ASSERT_EXPR expressions inserted",
5165 /* Traverse the flowgraph looking for conditional jumps to insert range
5166 expressions. These range expressions are meant to provide information
5167 to optimizations that need to reason in terms of value ranges. They
5168 will not be expanded into RTL. For instance, given:
5177 this pass will transform the code into:
5183 x = ASSERT_EXPR <x, x < y>
5188 y = ASSERT_EXPR <y, x <= y>
5192 The idea is that once copy and constant propagation have run, other
5193 optimizations will be able to determine what ranges of values can 'x'
5194 take in different paths of the code, simply by checking the reaching
5195 definition of 'x'. */
5198 insert_range_assertions (void)
5200 need_assert_for
= BITMAP_ALLOC (NULL
);
5201 asserts_for
= XCNEWVEC (assert_locus_t
, num_ssa_names
);
5203 calculate_dominance_info (CDI_DOMINATORS
);
5205 if (find_assert_locations ())
5207 process_assert_insertions ();
5208 update_ssa (TODO_update_ssa_no_phi
);
5211 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
5213 fprintf (dump_file
, "\nSSA form after inserting ASSERT_EXPRs\n");
5214 dump_function_to_file (current_function_decl
, dump_file
, dump_flags
);
5218 BITMAP_FREE (need_assert_for
);
5221 /* Checks one ARRAY_REF in REF, located at LOCUS. Ignores flexible arrays
5222 and "struct" hacks. If VRP can determine that the
5223 array subscript is a constant, check if it is outside valid
5224 range. If the array subscript is a RANGE, warn if it is
5225 non-overlapping with valid range.
5226 IGNORE_OFF_BY_ONE is true if the ARRAY_REF is inside a ADDR_EXPR. */
5229 check_array_ref (location_t location
, tree ref
, bool ignore_off_by_one
)
5231 value_range_t
* vr
= NULL
;
5232 tree low_sub
, up_sub
;
5233 tree low_bound
, up_bound
, up_bound_p1
;
5236 if (TREE_NO_WARNING (ref
))
5239 low_sub
= up_sub
= TREE_OPERAND (ref
, 1);
5240 up_bound
= array_ref_up_bound (ref
);
5242 /* Can not check flexible arrays. */
5244 || TREE_CODE (up_bound
) != INTEGER_CST
)
5247 /* Accesses to trailing arrays via pointers may access storage
5248 beyond the types array bounds. */
5249 base
= get_base_address (ref
);
5250 if (base
&& TREE_CODE (base
) == MEM_REF
)
5252 tree cref
, next
= NULL_TREE
;
5254 if (TREE_CODE (TREE_OPERAND (ref
, 0)) != COMPONENT_REF
)
5257 cref
= TREE_OPERAND (ref
, 0);
5258 if (TREE_CODE (TREE_TYPE (TREE_OPERAND (cref
, 0))) == RECORD_TYPE
)
5259 for (next
= DECL_CHAIN (TREE_OPERAND (cref
, 1));
5260 next
&& TREE_CODE (next
) != FIELD_DECL
;
5261 next
= DECL_CHAIN (next
))
5264 /* If this is the last field in a struct type or a field in a
5265 union type do not warn. */
5270 low_bound
= array_ref_low_bound (ref
);
5271 up_bound_p1
= int_const_binop (PLUS_EXPR
, up_bound
, integer_one_node
);
5273 if (TREE_CODE (low_sub
) == SSA_NAME
)
5275 vr
= get_value_range (low_sub
);
5276 if (vr
->type
== VR_RANGE
|| vr
->type
== VR_ANTI_RANGE
)
5278 low_sub
= vr
->type
== VR_RANGE
? vr
->max
: vr
->min
;
5279 up_sub
= vr
->type
== VR_RANGE
? vr
->min
: vr
->max
;
5283 if (vr
&& vr
->type
== VR_ANTI_RANGE
)
5285 if (TREE_CODE (up_sub
) == INTEGER_CST
5286 && tree_int_cst_lt (up_bound
, up_sub
)
5287 && TREE_CODE (low_sub
) == INTEGER_CST
5288 && tree_int_cst_lt (low_sub
, low_bound
))
5290 warning_at (location
, OPT_Warray_bounds
,
5291 "array subscript is outside array bounds");
5292 TREE_NO_WARNING (ref
) = 1;
5295 else if (TREE_CODE (up_sub
) == INTEGER_CST
5296 && (ignore_off_by_one
5297 ? (tree_int_cst_lt (up_bound
, up_sub
)
5298 && !tree_int_cst_equal (up_bound_p1
, up_sub
))
5299 : (tree_int_cst_lt (up_bound
, up_sub
)
5300 || tree_int_cst_equal (up_bound_p1
, up_sub
))))
5302 warning_at (location
, OPT_Warray_bounds
,
5303 "array subscript is above array bounds");
5304 TREE_NO_WARNING (ref
) = 1;
5306 else if (TREE_CODE (low_sub
) == INTEGER_CST
5307 && tree_int_cst_lt (low_sub
, low_bound
))
5309 warning_at (location
, OPT_Warray_bounds
,
5310 "array subscript is below array bounds");
5311 TREE_NO_WARNING (ref
) = 1;
5315 /* Searches if the expr T, located at LOCATION computes
5316 address of an ARRAY_REF, and call check_array_ref on it. */
5319 search_for_addr_array (tree t
, location_t location
)
5321 while (TREE_CODE (t
) == SSA_NAME
)
5323 gimple g
= SSA_NAME_DEF_STMT (t
);
5325 if (gimple_code (g
) != GIMPLE_ASSIGN
)
5328 if (get_gimple_rhs_class (gimple_assign_rhs_code (g
))
5329 != GIMPLE_SINGLE_RHS
)
5332 t
= gimple_assign_rhs1 (g
);
5336 /* We are only interested in addresses of ARRAY_REF's. */
5337 if (TREE_CODE (t
) != ADDR_EXPR
)
5340 /* Check each ARRAY_REFs in the reference chain. */
5343 if (TREE_CODE (t
) == ARRAY_REF
)
5344 check_array_ref (location
, t
, true /*ignore_off_by_one*/);
5346 t
= TREE_OPERAND (t
, 0);
5348 while (handled_component_p (t
));
5350 if (TREE_CODE (t
) == MEM_REF
5351 && TREE_CODE (TREE_OPERAND (t
, 0)) == ADDR_EXPR
5352 && !TREE_NO_WARNING (t
))
5354 tree tem
= TREE_OPERAND (TREE_OPERAND (t
, 0), 0);
5355 tree low_bound
, up_bound
, el_sz
;
5357 if (TREE_CODE (TREE_TYPE (tem
)) != ARRAY_TYPE
5358 || TREE_CODE (TREE_TYPE (TREE_TYPE (tem
))) == ARRAY_TYPE
5359 || !TYPE_DOMAIN (TREE_TYPE (tem
)))
5362 low_bound
= TYPE_MIN_VALUE (TYPE_DOMAIN (TREE_TYPE (tem
)));
5363 up_bound
= TYPE_MAX_VALUE (TYPE_DOMAIN (TREE_TYPE (tem
)));
5364 el_sz
= TYPE_SIZE_UNIT (TREE_TYPE (TREE_TYPE (tem
)));
5366 || TREE_CODE (low_bound
) != INTEGER_CST
5368 || TREE_CODE (up_bound
) != INTEGER_CST
5370 || TREE_CODE (el_sz
) != INTEGER_CST
)
5373 idx
= mem_ref_offset (t
);
5374 idx
= double_int_sdiv (idx
, tree_to_double_int (el_sz
), TRUNC_DIV_EXPR
);
5375 if (double_int_scmp (idx
, double_int_zero
) < 0)
5377 warning_at (location
, OPT_Warray_bounds
,
5378 "array subscript is below array bounds");
5379 TREE_NO_WARNING (t
) = 1;
5381 else if (double_int_scmp (idx
,
5384 (tree_to_double_int (up_bound
),
5386 (tree_to_double_int (low_bound
))),
5387 double_int_one
)) > 0)
5389 warning_at (location
, OPT_Warray_bounds
,
5390 "array subscript is above array bounds");
5391 TREE_NO_WARNING (t
) = 1;
5396 /* walk_tree() callback that checks if *TP is
5397 an ARRAY_REF inside an ADDR_EXPR (in which an array
5398 subscript one outside the valid range is allowed). Call
5399 check_array_ref for each ARRAY_REF found. The location is
5403 check_array_bounds (tree
*tp
, int *walk_subtree
, void *data
)
5406 struct walk_stmt_info
*wi
= (struct walk_stmt_info
*) data
;
5407 location_t location
;
5409 if (EXPR_HAS_LOCATION (t
))
5410 location
= EXPR_LOCATION (t
);
5413 location_t
*locp
= (location_t
*) wi
->info
;
5417 *walk_subtree
= TRUE
;
5419 if (TREE_CODE (t
) == ARRAY_REF
)
5420 check_array_ref (location
, t
, false /*ignore_off_by_one*/);
5422 if (TREE_CODE (t
) == MEM_REF
5423 || (TREE_CODE (t
) == RETURN_EXPR
&& TREE_OPERAND (t
, 0)))
5424 search_for_addr_array (TREE_OPERAND (t
, 0), location
);
5426 if (TREE_CODE (t
) == ADDR_EXPR
)
5427 *walk_subtree
= FALSE
;
5432 /* Walk over all statements of all reachable BBs and call check_array_bounds
5436 check_all_array_refs (void)
5439 gimple_stmt_iterator si
;
5445 bool executable
= false;
5447 /* Skip blocks that were found to be unreachable. */
5448 FOR_EACH_EDGE (e
, ei
, bb
->preds
)
5449 executable
|= !!(e
->flags
& EDGE_EXECUTABLE
);
5453 for (si
= gsi_start_bb (bb
); !gsi_end_p (si
); gsi_next (&si
))
5455 gimple stmt
= gsi_stmt (si
);
5456 struct walk_stmt_info wi
;
5457 if (!gimple_has_location (stmt
))
5460 if (is_gimple_call (stmt
))
5463 size_t n
= gimple_call_num_args (stmt
);
5464 for (i
= 0; i
< n
; i
++)
5466 tree arg
= gimple_call_arg (stmt
, i
);
5467 search_for_addr_array (arg
, gimple_location (stmt
));
5472 memset (&wi
, 0, sizeof (wi
));
5473 wi
.info
= CONST_CAST (void *, (const void *)
5474 gimple_location_ptr (stmt
));
5476 walk_gimple_op (gsi_stmt (si
),
5484 /* Convert range assertion expressions into the implied copies and
5485 copy propagate away the copies. Doing the trivial copy propagation
5486 here avoids the need to run the full copy propagation pass after
5489 FIXME, this will eventually lead to copy propagation removing the
5490 names that had useful range information attached to them. For
5491 instance, if we had the assertion N_i = ASSERT_EXPR <N_j, N_j > 3>,
5492 then N_i will have the range [3, +INF].
5494 However, by converting the assertion into the implied copy
5495 operation N_i = N_j, we will then copy-propagate N_j into the uses
5496 of N_i and lose the range information. We may want to hold on to
5497 ASSERT_EXPRs a little while longer as the ranges could be used in
5498 things like jump threading.
5500 The problem with keeping ASSERT_EXPRs around is that passes after
5501 VRP need to handle them appropriately.
5503 Another approach would be to make the range information a first
5504 class property of the SSA_NAME so that it can be queried from
5505 any pass. This is made somewhat more complex by the need for
5506 multiple ranges to be associated with one SSA_NAME. */
5509 remove_range_assertions (void)
5512 gimple_stmt_iterator si
;
5514 /* Note that the BSI iterator bump happens at the bottom of the
5515 loop and no bump is necessary if we're removing the statement
5516 referenced by the current BSI. */
5518 for (si
= gsi_start_bb (bb
); !gsi_end_p (si
);)
5520 gimple stmt
= gsi_stmt (si
);
5523 if (is_gimple_assign (stmt
)
5524 && gimple_assign_rhs_code (stmt
) == ASSERT_EXPR
)
5526 tree rhs
= gimple_assign_rhs1 (stmt
);
5528 tree cond
= fold (ASSERT_EXPR_COND (rhs
));
5529 use_operand_p use_p
;
5530 imm_use_iterator iter
;
5532 gcc_assert (cond
!= boolean_false_node
);
5534 /* Propagate the RHS into every use of the LHS. */
5535 var
= ASSERT_EXPR_VAR (rhs
);
5536 FOR_EACH_IMM_USE_STMT (use_stmt
, iter
,
5537 gimple_assign_lhs (stmt
))
5538 FOR_EACH_IMM_USE_ON_STMT (use_p
, iter
)
5540 SET_USE (use_p
, var
);
5541 gcc_assert (TREE_CODE (var
) == SSA_NAME
);
5544 /* And finally, remove the copy, it is not needed. */
5545 gsi_remove (&si
, true);
5546 release_defs (stmt
);
5554 /* Return true if STMT is interesting for VRP. */
5557 stmt_interesting_for_vrp (gimple stmt
)
5559 if (gimple_code (stmt
) == GIMPLE_PHI
5560 && is_gimple_reg (gimple_phi_result (stmt
))
5561 && (INTEGRAL_TYPE_P (TREE_TYPE (gimple_phi_result (stmt
)))
5562 || POINTER_TYPE_P (TREE_TYPE (gimple_phi_result (stmt
)))))
5564 else if (is_gimple_assign (stmt
) || is_gimple_call (stmt
))
5566 tree lhs
= gimple_get_lhs (stmt
);
5568 /* In general, assignments with virtual operands are not useful
5569 for deriving ranges, with the obvious exception of calls to
5570 builtin functions. */
5571 if (lhs
&& TREE_CODE (lhs
) == SSA_NAME
5572 && (INTEGRAL_TYPE_P (TREE_TYPE (lhs
))
5573 || POINTER_TYPE_P (TREE_TYPE (lhs
)))
5574 && ((is_gimple_call (stmt
)
5575 && gimple_call_fndecl (stmt
) != NULL_TREE
5576 && DECL_IS_BUILTIN (gimple_call_fndecl (stmt
)))
5577 || !gimple_vuse (stmt
)))
5580 else if (gimple_code (stmt
) == GIMPLE_COND
5581 || gimple_code (stmt
) == GIMPLE_SWITCH
)
5588 /* Initialize local data structures for VRP. */
5591 vrp_initialize (void)
5595 vr_value
= XCNEWVEC (value_range_t
*, num_ssa_names
);
5596 vr_phi_edge_counts
= XCNEWVEC (int, num_ssa_names
);
5600 gimple_stmt_iterator si
;
5602 for (si
= gsi_start_phis (bb
); !gsi_end_p (si
); gsi_next (&si
))
5604 gimple phi
= gsi_stmt (si
);
5605 if (!stmt_interesting_for_vrp (phi
))
5607 tree lhs
= PHI_RESULT (phi
);
5608 set_value_range_to_varying (get_value_range (lhs
));
5609 prop_set_simulate_again (phi
, false);
5612 prop_set_simulate_again (phi
, true);
5615 for (si
= gsi_start_bb (bb
); !gsi_end_p (si
); gsi_next (&si
))
5617 gimple stmt
= gsi_stmt (si
);
5619 /* If the statement is a control insn, then we do not
5620 want to avoid simulating the statement once. Failure
5621 to do so means that those edges will never get added. */
5622 if (stmt_ends_bb_p (stmt
))
5623 prop_set_simulate_again (stmt
, true);
5624 else if (!stmt_interesting_for_vrp (stmt
))
5628 FOR_EACH_SSA_TREE_OPERAND (def
, stmt
, i
, SSA_OP_DEF
)
5629 set_value_range_to_varying (get_value_range (def
));
5630 prop_set_simulate_again (stmt
, false);
5633 prop_set_simulate_again (stmt
, true);
5638 /* Return the singleton value-range for NAME or NAME. */
5641 vrp_valueize (tree name
)
5643 if (TREE_CODE (name
) == SSA_NAME
)
5645 value_range_t
*vr
= get_value_range (name
);
5646 if (vr
->type
== VR_RANGE
5647 && (vr
->min
== vr
->max
5648 || operand_equal_p (vr
->min
, vr
->max
, 0)))
5654 /* Visit assignment STMT. If it produces an interesting range, record
5655 the SSA name in *OUTPUT_P. */
5657 static enum ssa_prop_result
5658 vrp_visit_assignment_or_call (gimple stmt
, tree
*output_p
)
5662 enum gimple_code code
= gimple_code (stmt
);
5663 lhs
= gimple_get_lhs (stmt
);
5665 /* We only keep track of ranges in integral and pointer types. */
5666 if (TREE_CODE (lhs
) == SSA_NAME
5667 && ((INTEGRAL_TYPE_P (TREE_TYPE (lhs
))
5668 /* It is valid to have NULL MIN/MAX values on a type. See
5669 build_range_type. */
5670 && TYPE_MIN_VALUE (TREE_TYPE (lhs
))
5671 && TYPE_MAX_VALUE (TREE_TYPE (lhs
)))
5672 || POINTER_TYPE_P (TREE_TYPE (lhs
))))
5674 value_range_t new_vr
= { VR_UNDEFINED
, NULL_TREE
, NULL_TREE
, NULL
};
5676 /* Try folding the statement to a constant first. */
5677 tree tem
= gimple_fold_stmt_to_constant (stmt
, vrp_valueize
);
5678 if (tem
&& !is_overflow_infinity (tem
))
5679 set_value_range (&new_vr
, VR_RANGE
, tem
, tem
, NULL
);
5680 /* Then dispatch to value-range extracting functions. */
5681 else if (code
== GIMPLE_CALL
)
5682 extract_range_basic (&new_vr
, stmt
);
5684 extract_range_from_assignment (&new_vr
, stmt
);
5686 if (update_value_range (lhs
, &new_vr
))
5690 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
5692 fprintf (dump_file
, "Found new range for ");
5693 print_generic_expr (dump_file
, lhs
, 0);
5694 fprintf (dump_file
, ": ");
5695 dump_value_range (dump_file
, &new_vr
);
5696 fprintf (dump_file
, "\n\n");
5699 if (new_vr
.type
== VR_VARYING
)
5700 return SSA_PROP_VARYING
;
5702 return SSA_PROP_INTERESTING
;
5705 return SSA_PROP_NOT_INTERESTING
;
5708 /* Every other statement produces no useful ranges. */
5709 FOR_EACH_SSA_TREE_OPERAND (def
, stmt
, iter
, SSA_OP_DEF
)
5710 set_value_range_to_varying (get_value_range (def
));
5712 return SSA_PROP_VARYING
;
5715 /* Helper that gets the value range of the SSA_NAME with version I
5716 or a symbolic range containing the SSA_NAME only if the value range
5717 is varying or undefined. */
5719 static inline value_range_t
5720 get_vr_for_comparison (int i
)
5722 value_range_t vr
= *(vr_value
[i
]);
5724 /* If name N_i does not have a valid range, use N_i as its own
5725 range. This allows us to compare against names that may
5726 have N_i in their ranges. */
5727 if (vr
.type
== VR_VARYING
|| vr
.type
== VR_UNDEFINED
)
5730 vr
.min
= ssa_name (i
);
5731 vr
.max
= ssa_name (i
);
5737 /* Compare all the value ranges for names equivalent to VAR with VAL
5738 using comparison code COMP. Return the same value returned by
5739 compare_range_with_value, including the setting of
5740 *STRICT_OVERFLOW_P. */
5743 compare_name_with_value (enum tree_code comp
, tree var
, tree val
,
5744 bool *strict_overflow_p
)
5750 int used_strict_overflow
;
5752 value_range_t equiv_vr
;
5754 /* Get the set of equivalences for VAR. */
5755 e
= get_value_range (var
)->equiv
;
5757 /* Start at -1. Set it to 0 if we do a comparison without relying
5758 on overflow, or 1 if all comparisons rely on overflow. */
5759 used_strict_overflow
= -1;
5761 /* Compare vars' value range with val. */
5762 equiv_vr
= get_vr_for_comparison (SSA_NAME_VERSION (var
));
5764 retval
= compare_range_with_value (comp
, &equiv_vr
, val
, &sop
);
5766 used_strict_overflow
= sop
? 1 : 0;
5768 /* If the equiv set is empty we have done all work we need to do. */
5772 && used_strict_overflow
> 0)
5773 *strict_overflow_p
= true;
5777 EXECUTE_IF_SET_IN_BITMAP (e
, 0, i
, bi
)
5779 equiv_vr
= get_vr_for_comparison (i
);
5781 t
= compare_range_with_value (comp
, &equiv_vr
, val
, &sop
);
5784 /* If we get different answers from different members
5785 of the equivalence set this check must be in a dead
5786 code region. Folding it to a trap representation
5787 would be correct here. For now just return don't-know. */
5797 used_strict_overflow
= 0;
5798 else if (used_strict_overflow
< 0)
5799 used_strict_overflow
= 1;
5804 && used_strict_overflow
> 0)
5805 *strict_overflow_p
= true;
5811 /* Given a comparison code COMP and names N1 and N2, compare all the
5812 ranges equivalent to N1 against all the ranges equivalent to N2
5813 to determine the value of N1 COMP N2. Return the same value
5814 returned by compare_ranges. Set *STRICT_OVERFLOW_P to indicate
5815 whether we relied on an overflow infinity in the comparison. */
5819 compare_names (enum tree_code comp
, tree n1
, tree n2
,
5820 bool *strict_overflow_p
)
5824 bitmap_iterator bi1
, bi2
;
5826 int used_strict_overflow
;
5827 static bitmap_obstack
*s_obstack
= NULL
;
5828 static bitmap s_e1
= NULL
, s_e2
= NULL
;
5830 /* Compare the ranges of every name equivalent to N1 against the
5831 ranges of every name equivalent to N2. */
5832 e1
= get_value_range (n1
)->equiv
;
5833 e2
= get_value_range (n2
)->equiv
;
5835 /* Use the fake bitmaps if e1 or e2 are not available. */
5836 if (s_obstack
== NULL
)
5838 s_obstack
= XNEW (bitmap_obstack
);
5839 bitmap_obstack_initialize (s_obstack
);
5840 s_e1
= BITMAP_ALLOC (s_obstack
);
5841 s_e2
= BITMAP_ALLOC (s_obstack
);
5848 /* Add N1 and N2 to their own set of equivalences to avoid
5849 duplicating the body of the loop just to check N1 and N2
5851 bitmap_set_bit (e1
, SSA_NAME_VERSION (n1
));
5852 bitmap_set_bit (e2
, SSA_NAME_VERSION (n2
));
5854 /* If the equivalence sets have a common intersection, then the two
5855 names can be compared without checking their ranges. */
5856 if (bitmap_intersect_p (e1
, e2
))
5858 bitmap_clear_bit (e1
, SSA_NAME_VERSION (n1
));
5859 bitmap_clear_bit (e2
, SSA_NAME_VERSION (n2
));
5861 return (comp
== EQ_EXPR
|| comp
== GE_EXPR
|| comp
== LE_EXPR
)
5863 : boolean_false_node
;
5866 /* Start at -1. Set it to 0 if we do a comparison without relying
5867 on overflow, or 1 if all comparisons rely on overflow. */
5868 used_strict_overflow
= -1;
5870 /* Otherwise, compare all the equivalent ranges. First, add N1 and
5871 N2 to their own set of equivalences to avoid duplicating the body
5872 of the loop just to check N1 and N2 ranges. */
5873 EXECUTE_IF_SET_IN_BITMAP (e1
, 0, i1
, bi1
)
5875 value_range_t vr1
= get_vr_for_comparison (i1
);
5877 t
= retval
= NULL_TREE
;
5878 EXECUTE_IF_SET_IN_BITMAP (e2
, 0, i2
, bi2
)
5882 value_range_t vr2
= get_vr_for_comparison (i2
);
5884 t
= compare_ranges (comp
, &vr1
, &vr2
, &sop
);
5887 /* If we get different answers from different members
5888 of the equivalence set this check must be in a dead
5889 code region. Folding it to a trap representation
5890 would be correct here. For now just return don't-know. */
5894 bitmap_clear_bit (e1
, SSA_NAME_VERSION (n1
));
5895 bitmap_clear_bit (e2
, SSA_NAME_VERSION (n2
));
5901 used_strict_overflow
= 0;
5902 else if (used_strict_overflow
< 0)
5903 used_strict_overflow
= 1;
5909 bitmap_clear_bit (e1
, SSA_NAME_VERSION (n1
));
5910 bitmap_clear_bit (e2
, SSA_NAME_VERSION (n2
));
5911 if (used_strict_overflow
> 0)
5912 *strict_overflow_p
= true;
5917 /* None of the equivalent ranges are useful in computing this
5919 bitmap_clear_bit (e1
, SSA_NAME_VERSION (n1
));
5920 bitmap_clear_bit (e2
, SSA_NAME_VERSION (n2
));
5924 /* Helper function for vrp_evaluate_conditional_warnv. */
5927 vrp_evaluate_conditional_warnv_with_ops_using_ranges (enum tree_code code
,
5929 bool * strict_overflow_p
)
5931 value_range_t
*vr0
, *vr1
;
5933 vr0
= (TREE_CODE (op0
) == SSA_NAME
) ? get_value_range (op0
) : NULL
;
5934 vr1
= (TREE_CODE (op1
) == SSA_NAME
) ? get_value_range (op1
) : NULL
;
5937 return compare_ranges (code
, vr0
, vr1
, strict_overflow_p
);
5938 else if (vr0
&& vr1
== NULL
)
5939 return compare_range_with_value (code
, vr0
, op1
, strict_overflow_p
);
5940 else if (vr0
== NULL
&& vr1
)
5941 return (compare_range_with_value
5942 (swap_tree_comparison (code
), vr1
, op0
, strict_overflow_p
));
5946 /* Helper function for vrp_evaluate_conditional_warnv. */
5949 vrp_evaluate_conditional_warnv_with_ops (enum tree_code code
, tree op0
,
5950 tree op1
, bool use_equiv_p
,
5951 bool *strict_overflow_p
, bool *only_ranges
)
5955 *only_ranges
= true;
5957 /* We only deal with integral and pointer types. */
5958 if (!INTEGRAL_TYPE_P (TREE_TYPE (op0
))
5959 && !POINTER_TYPE_P (TREE_TYPE (op0
)))
5965 && (ret
= vrp_evaluate_conditional_warnv_with_ops_using_ranges
5966 (code
, op0
, op1
, strict_overflow_p
)))
5968 *only_ranges
= false;
5969 if (TREE_CODE (op0
) == SSA_NAME
&& TREE_CODE (op1
) == SSA_NAME
)
5970 return compare_names (code
, op0
, op1
, strict_overflow_p
);
5971 else if (TREE_CODE (op0
) == SSA_NAME
)
5972 return compare_name_with_value (code
, op0
, op1
, strict_overflow_p
);
5973 else if (TREE_CODE (op1
) == SSA_NAME
)
5974 return (compare_name_with_value
5975 (swap_tree_comparison (code
), op1
, op0
, strict_overflow_p
));
5978 return vrp_evaluate_conditional_warnv_with_ops_using_ranges (code
, op0
, op1
,
5983 /* Given (CODE OP0 OP1) within STMT, try to simplify it based on value range
5984 information. Return NULL if the conditional can not be evaluated.
5985 The ranges of all the names equivalent with the operands in COND
5986 will be used when trying to compute the value. If the result is
5987 based on undefined signed overflow, issue a warning if
5991 vrp_evaluate_conditional (enum tree_code code
, tree op0
, tree op1
, gimple stmt
)
5997 /* Some passes and foldings leak constants with overflow flag set
5998 into the IL. Avoid doing wrong things with these and bail out. */
5999 if ((TREE_CODE (op0
) == INTEGER_CST
6000 && TREE_OVERFLOW (op0
))
6001 || (TREE_CODE (op1
) == INTEGER_CST
6002 && TREE_OVERFLOW (op1
)))
6006 ret
= vrp_evaluate_conditional_warnv_with_ops (code
, op0
, op1
, true, &sop
,
6011 enum warn_strict_overflow_code wc
;
6012 const char* warnmsg
;
6014 if (is_gimple_min_invariant (ret
))
6016 wc
= WARN_STRICT_OVERFLOW_CONDITIONAL
;
6017 warnmsg
= G_("assuming signed overflow does not occur when "
6018 "simplifying conditional to constant");
6022 wc
= WARN_STRICT_OVERFLOW_COMPARISON
;
6023 warnmsg
= G_("assuming signed overflow does not occur when "
6024 "simplifying conditional");
6027 if (issue_strict_overflow_warning (wc
))
6029 location_t location
;
6031 if (!gimple_has_location (stmt
))
6032 location
= input_location
;
6034 location
= gimple_location (stmt
);
6035 warning_at (location
, OPT_Wstrict_overflow
, "%s", warnmsg
);
6039 if (warn_type_limits
6040 && ret
&& only_ranges
6041 && TREE_CODE_CLASS (code
) == tcc_comparison
6042 && TREE_CODE (op0
) == SSA_NAME
)
6044 /* If the comparison is being folded and the operand on the LHS
6045 is being compared against a constant value that is outside of
6046 the natural range of OP0's type, then the predicate will
6047 always fold regardless of the value of OP0. If -Wtype-limits
6048 was specified, emit a warning. */
6049 tree type
= TREE_TYPE (op0
);
6050 value_range_t
*vr0
= get_value_range (op0
);
6052 if (vr0
->type
!= VR_VARYING
6053 && INTEGRAL_TYPE_P (type
)
6054 && vrp_val_is_min (vr0
->min
)
6055 && vrp_val_is_max (vr0
->max
)
6056 && is_gimple_min_invariant (op1
))
6058 location_t location
;
6060 if (!gimple_has_location (stmt
))
6061 location
= input_location
;
6063 location
= gimple_location (stmt
);
6065 warning_at (location
, OPT_Wtype_limits
,
6067 ? G_("comparison always false "
6068 "due to limited range of data type")
6069 : G_("comparison always true "
6070 "due to limited range of data type"));
6078 /* Visit conditional statement STMT. If we can determine which edge
6079 will be taken out of STMT's basic block, record it in
6080 *TAKEN_EDGE_P and return SSA_PROP_INTERESTING. Otherwise, return
6081 SSA_PROP_VARYING. */
6083 static enum ssa_prop_result
6084 vrp_visit_cond_stmt (gimple stmt
, edge
*taken_edge_p
)
6089 *taken_edge_p
= NULL
;
6091 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
6096 fprintf (dump_file
, "\nVisiting conditional with predicate: ");
6097 print_gimple_stmt (dump_file
, stmt
, 0, 0);
6098 fprintf (dump_file
, "\nWith known ranges\n");
6100 FOR_EACH_SSA_TREE_OPERAND (use
, stmt
, i
, SSA_OP_USE
)
6102 fprintf (dump_file
, "\t");
6103 print_generic_expr (dump_file
, use
, 0);
6104 fprintf (dump_file
, ": ");
6105 dump_value_range (dump_file
, vr_value
[SSA_NAME_VERSION (use
)]);
6108 fprintf (dump_file
, "\n");
6111 /* Compute the value of the predicate COND by checking the known
6112 ranges of each of its operands.
6114 Note that we cannot evaluate all the equivalent ranges here
6115 because those ranges may not yet be final and with the current
6116 propagation strategy, we cannot determine when the value ranges
6117 of the names in the equivalence set have changed.
6119 For instance, given the following code fragment
6123 i_14 = ASSERT_EXPR <i_5, i_5 != 0>
6127 Assume that on the first visit to i_14, i_5 has the temporary
6128 range [8, 8] because the second argument to the PHI function is
6129 not yet executable. We derive the range ~[0, 0] for i_14 and the
6130 equivalence set { i_5 }. So, when we visit 'if (i_14 == 1)' for
6131 the first time, since i_14 is equivalent to the range [8, 8], we
6132 determine that the predicate is always false.
6134 On the next round of propagation, i_13 is determined to be
6135 VARYING, which causes i_5 to drop down to VARYING. So, another
6136 visit to i_14 is scheduled. In this second visit, we compute the
6137 exact same range and equivalence set for i_14, namely ~[0, 0] and
6138 { i_5 }. But we did not have the previous range for i_5
6139 registered, so vrp_visit_assignment thinks that the range for
6140 i_14 has not changed. Therefore, the predicate 'if (i_14 == 1)'
6141 is not visited again, which stops propagation from visiting
6142 statements in the THEN clause of that if().
6144 To properly fix this we would need to keep the previous range
6145 value for the names in the equivalence set. This way we would've
6146 discovered that from one visit to the other i_5 changed from
6147 range [8, 8] to VR_VARYING.
6149 However, fixing this apparent limitation may not be worth the
6150 additional checking. Testing on several code bases (GCC, DLV,
6151 MICO, TRAMP3D and SPEC2000) showed that doing this results in
6152 4 more predicates folded in SPEC. */
6155 val
= vrp_evaluate_conditional_warnv_with_ops (gimple_cond_code (stmt
),
6156 gimple_cond_lhs (stmt
),
6157 gimple_cond_rhs (stmt
),
6162 *taken_edge_p
= find_taken_edge (gimple_bb (stmt
), val
);
6165 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
6167 "\nIgnoring predicate evaluation because "
6168 "it assumes that signed overflow is undefined");
6173 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
6175 fprintf (dump_file
, "\nPredicate evaluates to: ");
6176 if (val
== NULL_TREE
)
6177 fprintf (dump_file
, "DON'T KNOW\n");
6179 print_generic_stmt (dump_file
, val
, 0);
6182 return (*taken_edge_p
) ? SSA_PROP_INTERESTING
: SSA_PROP_VARYING
;
6185 /* Searches the case label vector VEC for the index *IDX of the CASE_LABEL
6186 that includes the value VAL. The search is restricted to the range
6187 [START_IDX, n - 1] where n is the size of VEC.
6189 If there is a CASE_LABEL for VAL, its index is placed in IDX and true is
6192 If there is no CASE_LABEL for VAL and there is one that is larger than VAL,
6193 it is placed in IDX and false is returned.
6195 If VAL is larger than any CASE_LABEL, n is placed on IDX and false is
6199 find_case_label_index (gimple stmt
, size_t start_idx
, tree val
, size_t *idx
)
6201 size_t n
= gimple_switch_num_labels (stmt
);
6204 /* Find case label for minimum of the value range or the next one.
6205 At each iteration we are searching in [low, high - 1]. */
6207 for (low
= start_idx
, high
= n
; high
!= low
; )
6211 /* Note that i != high, so we never ask for n. */
6212 size_t i
= (high
+ low
) / 2;
6213 t
= gimple_switch_label (stmt
, i
);
6215 /* Cache the result of comparing CASE_LOW and val. */
6216 cmp
= tree_int_cst_compare (CASE_LOW (t
), val
);
6220 /* Ranges cannot be empty. */
6229 if (CASE_HIGH (t
) != NULL
6230 && tree_int_cst_compare (CASE_HIGH (t
), val
) >= 0)
6242 /* Searches the case label vector VEC for the range of CASE_LABELs that is used
6243 for values between MIN and MAX. The first index is placed in MIN_IDX. The
6244 last index is placed in MAX_IDX. If the range of CASE_LABELs is empty
6245 then MAX_IDX < MIN_IDX.
6246 Returns true if the default label is not needed. */
6249 find_case_label_range (gimple stmt
, tree min
, tree max
, size_t *min_idx
,
6253 bool min_take_default
= !find_case_label_index (stmt
, 1, min
, &i
);
6254 bool max_take_default
= !find_case_label_index (stmt
, i
, max
, &j
);
6258 && max_take_default
)
6260 /* Only the default case label reached.
6261 Return an empty range. */
6268 bool take_default
= min_take_default
|| max_take_default
;
6272 if (max_take_default
)
6275 /* If the case label range is continuous, we do not need
6276 the default case label. Verify that. */
6277 high
= CASE_LOW (gimple_switch_label (stmt
, i
));
6278 if (CASE_HIGH (gimple_switch_label (stmt
, i
)))
6279 high
= CASE_HIGH (gimple_switch_label (stmt
, i
));
6280 for (k
= i
+ 1; k
<= j
; ++k
)
6282 low
= CASE_LOW (gimple_switch_label (stmt
, k
));
6283 if (!integer_onep (int_const_binop (MINUS_EXPR
, low
, high
)))
6285 take_default
= true;
6289 if (CASE_HIGH (gimple_switch_label (stmt
, k
)))
6290 high
= CASE_HIGH (gimple_switch_label (stmt
, k
));
6295 return !take_default
;
6299 /* Visit switch statement STMT. If we can determine which edge
6300 will be taken out of STMT's basic block, record it in
6301 *TAKEN_EDGE_P and return SSA_PROP_INTERESTING. Otherwise, return
6302 SSA_PROP_VARYING. */
6304 static enum ssa_prop_result
6305 vrp_visit_switch_stmt (gimple stmt
, edge
*taken_edge_p
)
6309 size_t i
= 0, j
= 0;
6312 *taken_edge_p
= NULL
;
6313 op
= gimple_switch_index (stmt
);
6314 if (TREE_CODE (op
) != SSA_NAME
)
6315 return SSA_PROP_VARYING
;
6317 vr
= get_value_range (op
);
6318 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
6320 fprintf (dump_file
, "\nVisiting switch expression with operand ");
6321 print_generic_expr (dump_file
, op
, 0);
6322 fprintf (dump_file
, " with known range ");
6323 dump_value_range (dump_file
, vr
);
6324 fprintf (dump_file
, "\n");
6327 if (vr
->type
!= VR_RANGE
6328 || symbolic_range_p (vr
))
6329 return SSA_PROP_VARYING
;
6331 /* Find the single edge that is taken from the switch expression. */
6332 take_default
= !find_case_label_range (stmt
, vr
->min
, vr
->max
, &i
, &j
);
6334 /* Check if the range spans no CASE_LABEL. If so, we only reach the default
6338 gcc_assert (take_default
);
6339 val
= gimple_switch_default_label (stmt
);
6343 /* Check if labels with index i to j and maybe the default label
6344 are all reaching the same label. */
6346 val
= gimple_switch_label (stmt
, i
);
6348 && CASE_LABEL (gimple_switch_default_label (stmt
))
6349 != CASE_LABEL (val
))
6351 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
6352 fprintf (dump_file
, " not a single destination for this "
6354 return SSA_PROP_VARYING
;
6356 for (++i
; i
<= j
; ++i
)
6358 if (CASE_LABEL (gimple_switch_label (stmt
, i
)) != CASE_LABEL (val
))
6360 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
6361 fprintf (dump_file
, " not a single destination for this "
6363 return SSA_PROP_VARYING
;
6368 *taken_edge_p
= find_edge (gimple_bb (stmt
),
6369 label_to_block (CASE_LABEL (val
)));
6371 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
6373 fprintf (dump_file
, " will take edge to ");
6374 print_generic_stmt (dump_file
, CASE_LABEL (val
), 0);
6377 return SSA_PROP_INTERESTING
;
6381 /* Evaluate statement STMT. If the statement produces a useful range,
6382 return SSA_PROP_INTERESTING and record the SSA name with the
6383 interesting range into *OUTPUT_P.
6385 If STMT is a conditional branch and we can determine its truth
6386 value, the taken edge is recorded in *TAKEN_EDGE_P.
6388 If STMT produces a varying value, return SSA_PROP_VARYING. */
6390 static enum ssa_prop_result
6391 vrp_visit_stmt (gimple stmt
, edge
*taken_edge_p
, tree
*output_p
)
6396 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
6398 fprintf (dump_file
, "\nVisiting statement:\n");
6399 print_gimple_stmt (dump_file
, stmt
, 0, dump_flags
);
6400 fprintf (dump_file
, "\n");
6403 if (!stmt_interesting_for_vrp (stmt
))
6404 gcc_assert (stmt_ends_bb_p (stmt
));
6405 else if (is_gimple_assign (stmt
) || is_gimple_call (stmt
))
6407 /* In general, assignments with virtual operands are not useful
6408 for deriving ranges, with the obvious exception of calls to
6409 builtin functions. */
6410 if ((is_gimple_call (stmt
)
6411 && gimple_call_fndecl (stmt
) != NULL_TREE
6412 && DECL_IS_BUILTIN (gimple_call_fndecl (stmt
)))
6413 || !gimple_vuse (stmt
))
6414 return vrp_visit_assignment_or_call (stmt
, output_p
);
6416 else if (gimple_code (stmt
) == GIMPLE_COND
)
6417 return vrp_visit_cond_stmt (stmt
, taken_edge_p
);
6418 else if (gimple_code (stmt
) == GIMPLE_SWITCH
)
6419 return vrp_visit_switch_stmt (stmt
, taken_edge_p
);
6421 /* All other statements produce nothing of interest for VRP, so mark
6422 their outputs varying and prevent further simulation. */
6423 FOR_EACH_SSA_TREE_OPERAND (def
, stmt
, iter
, SSA_OP_DEF
)
6424 set_value_range_to_varying (get_value_range (def
));
6426 return SSA_PROP_VARYING
;
6430 /* Meet operation for value ranges. Given two value ranges VR0 and
6431 VR1, store in VR0 a range that contains both VR0 and VR1. This
6432 may not be the smallest possible such range. */
6435 vrp_meet (value_range_t
*vr0
, value_range_t
*vr1
)
6437 if (vr0
->type
== VR_UNDEFINED
)
6439 copy_value_range (vr0
, vr1
);
6443 if (vr1
->type
== VR_UNDEFINED
)
6445 /* Nothing to do. VR0 already has the resulting range. */
6449 if (vr0
->type
== VR_VARYING
)
6451 /* Nothing to do. VR0 already has the resulting range. */
6455 if (vr1
->type
== VR_VARYING
)
6457 set_value_range_to_varying (vr0
);
6461 if (vr0
->type
== VR_RANGE
&& vr1
->type
== VR_RANGE
)
6466 /* Compute the convex hull of the ranges. The lower limit of
6467 the new range is the minimum of the two ranges. If they
6468 cannot be compared, then give up. */
6469 cmp
= compare_values (vr0
->min
, vr1
->min
);
6470 if (cmp
== 0 || cmp
== 1)
6477 /* Similarly, the upper limit of the new range is the maximum
6478 of the two ranges. If they cannot be compared, then
6480 cmp
= compare_values (vr0
->max
, vr1
->max
);
6481 if (cmp
== 0 || cmp
== -1)
6488 /* Check for useless ranges. */
6489 if (INTEGRAL_TYPE_P (TREE_TYPE (min
))
6490 && ((vrp_val_is_min (min
) || is_overflow_infinity (min
))
6491 && (vrp_val_is_max (max
) || is_overflow_infinity (max
))))
6494 /* The resulting set of equivalences is the intersection of
6496 if (vr0
->equiv
&& vr1
->equiv
&& vr0
->equiv
!= vr1
->equiv
)
6497 bitmap_and_into (vr0
->equiv
, vr1
->equiv
);
6498 else if (vr0
->equiv
&& !vr1
->equiv
)
6499 bitmap_clear (vr0
->equiv
);
6501 set_value_range (vr0
, vr0
->type
, min
, max
, vr0
->equiv
);
6503 else if (vr0
->type
== VR_ANTI_RANGE
&& vr1
->type
== VR_ANTI_RANGE
)
6505 /* Two anti-ranges meet only if their complements intersect.
6506 Only handle the case of identical ranges. */
6507 if (compare_values (vr0
->min
, vr1
->min
) == 0
6508 && compare_values (vr0
->max
, vr1
->max
) == 0
6509 && compare_values (vr0
->min
, vr0
->max
) == 0)
6511 /* The resulting set of equivalences is the intersection of
6513 if (vr0
->equiv
&& vr1
->equiv
&& vr0
->equiv
!= vr1
->equiv
)
6514 bitmap_and_into (vr0
->equiv
, vr1
->equiv
);
6515 else if (vr0
->equiv
&& !vr1
->equiv
)
6516 bitmap_clear (vr0
->equiv
);
6521 else if (vr0
->type
== VR_ANTI_RANGE
|| vr1
->type
== VR_ANTI_RANGE
)
6523 /* For a numeric range [VAL1, VAL2] and an anti-range ~[VAL3, VAL4],
6524 only handle the case where the ranges have an empty intersection.
6525 The result of the meet operation is the anti-range. */
6526 if (!symbolic_range_p (vr0
)
6527 && !symbolic_range_p (vr1
)
6528 && !value_ranges_intersect_p (vr0
, vr1
))
6530 /* Copy most of VR1 into VR0. Don't copy VR1's equivalence
6531 set. We need to compute the intersection of the two
6532 equivalence sets. */
6533 if (vr1
->type
== VR_ANTI_RANGE
)
6534 set_value_range (vr0
, vr1
->type
, vr1
->min
, vr1
->max
, vr0
->equiv
);
6536 /* The resulting set of equivalences is the intersection of
6538 if (vr0
->equiv
&& vr1
->equiv
&& vr0
->equiv
!= vr1
->equiv
)
6539 bitmap_and_into (vr0
->equiv
, vr1
->equiv
);
6540 else if (vr0
->equiv
&& !vr1
->equiv
)
6541 bitmap_clear (vr0
->equiv
);
6552 /* Failed to find an efficient meet. Before giving up and setting
6553 the result to VARYING, see if we can at least derive a useful
6554 anti-range. FIXME, all this nonsense about distinguishing
6555 anti-ranges from ranges is necessary because of the odd
6556 semantics of range_includes_zero_p and friends. */
6557 if (!symbolic_range_p (vr0
)
6558 && ((vr0
->type
== VR_RANGE
&& !range_includes_zero_p (vr0
))
6559 || (vr0
->type
== VR_ANTI_RANGE
&& range_includes_zero_p (vr0
)))
6560 && !symbolic_range_p (vr1
)
6561 && ((vr1
->type
== VR_RANGE
&& !range_includes_zero_p (vr1
))
6562 || (vr1
->type
== VR_ANTI_RANGE
&& range_includes_zero_p (vr1
))))
6564 set_value_range_to_nonnull (vr0
, TREE_TYPE (vr0
->min
));
6566 /* Since this meet operation did not result from the meeting of
6567 two equivalent names, VR0 cannot have any equivalences. */
6569 bitmap_clear (vr0
->equiv
);
6572 set_value_range_to_varying (vr0
);
6576 /* Visit all arguments for PHI node PHI that flow through executable
6577 edges. If a valid value range can be derived from all the incoming
6578 value ranges, set a new range for the LHS of PHI. */
6580 static enum ssa_prop_result
6581 vrp_visit_phi_node (gimple phi
)
6584 tree lhs
= PHI_RESULT (phi
);
6585 value_range_t
*lhs_vr
= get_value_range (lhs
);
6586 value_range_t vr_result
= { VR_UNDEFINED
, NULL_TREE
, NULL_TREE
, NULL
};
6587 int edges
, old_edges
;
6590 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
6592 fprintf (dump_file
, "\nVisiting PHI node: ");
6593 print_gimple_stmt (dump_file
, phi
, 0, dump_flags
);
6597 for (i
= 0; i
< gimple_phi_num_args (phi
); i
++)
6599 edge e
= gimple_phi_arg_edge (phi
, i
);
6601 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
6604 "\n Argument #%d (%d -> %d %sexecutable)\n",
6605 (int) i
, e
->src
->index
, e
->dest
->index
,
6606 (e
->flags
& EDGE_EXECUTABLE
) ? "" : "not ");
6609 if (e
->flags
& EDGE_EXECUTABLE
)
6611 tree arg
= PHI_ARG_DEF (phi
, i
);
6612 value_range_t vr_arg
;
6616 if (TREE_CODE (arg
) == SSA_NAME
)
6618 vr_arg
= *(get_value_range (arg
));
6622 if (is_overflow_infinity (arg
))
6624 arg
= copy_node (arg
);
6625 TREE_OVERFLOW (arg
) = 0;
6628 vr_arg
.type
= VR_RANGE
;
6631 vr_arg
.equiv
= NULL
;
6634 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
6636 fprintf (dump_file
, "\t");
6637 print_generic_expr (dump_file
, arg
, dump_flags
);
6638 fprintf (dump_file
, "\n\tValue: ");
6639 dump_value_range (dump_file
, &vr_arg
);
6640 fprintf (dump_file
, "\n");
6643 vrp_meet (&vr_result
, &vr_arg
);
6645 if (vr_result
.type
== VR_VARYING
)
6650 if (vr_result
.type
== VR_VARYING
)
6653 old_edges
= vr_phi_edge_counts
[SSA_NAME_VERSION (lhs
)];
6654 vr_phi_edge_counts
[SSA_NAME_VERSION (lhs
)] = edges
;
6656 /* To prevent infinite iterations in the algorithm, derive ranges
6657 when the new value is slightly bigger or smaller than the
6658 previous one. We don't do this if we have seen a new executable
6659 edge; this helps us avoid an overflow infinity for conditionals
6660 which are not in a loop. */
6662 && gimple_phi_num_args (phi
) > 1
6663 && edges
== old_edges
)
6665 int cmp_min
= compare_values (lhs_vr
->min
, vr_result
.min
);
6666 int cmp_max
= compare_values (lhs_vr
->max
, vr_result
.max
);
6668 /* For non VR_RANGE or for pointers fall back to varying if
6669 the range changed. */
6670 if ((lhs_vr
->type
!= VR_RANGE
|| vr_result
.type
!= VR_RANGE
6671 || POINTER_TYPE_P (TREE_TYPE (lhs
)))
6672 && (cmp_min
!= 0 || cmp_max
!= 0))
6675 /* If the new minimum is smaller or larger than the previous
6676 one, go all the way to -INF. In the first case, to avoid
6677 iterating millions of times to reach -INF, and in the
6678 other case to avoid infinite bouncing between different
6680 if (cmp_min
> 0 || cmp_min
< 0)
6682 if (!needs_overflow_infinity (TREE_TYPE (vr_result
.min
))
6683 || !vrp_var_may_overflow (lhs
, phi
))
6684 vr_result
.min
= TYPE_MIN_VALUE (TREE_TYPE (vr_result
.min
));
6685 else if (supports_overflow_infinity (TREE_TYPE (vr_result
.min
)))
6687 negative_overflow_infinity (TREE_TYPE (vr_result
.min
));
6690 /* Similarly, if the new maximum is smaller or larger than
6691 the previous one, go all the way to +INF. */
6692 if (cmp_max
< 0 || cmp_max
> 0)
6694 if (!needs_overflow_infinity (TREE_TYPE (vr_result
.max
))
6695 || !vrp_var_may_overflow (lhs
, phi
))
6696 vr_result
.max
= TYPE_MAX_VALUE (TREE_TYPE (vr_result
.max
));
6697 else if (supports_overflow_infinity (TREE_TYPE (vr_result
.max
)))
6699 positive_overflow_infinity (TREE_TYPE (vr_result
.max
));
6702 /* If we dropped either bound to +-INF then if this is a loop
6703 PHI node SCEV may known more about its value-range. */
6704 if ((cmp_min
> 0 || cmp_min
< 0
6705 || cmp_max
< 0 || cmp_max
> 0)
6707 && (l
= loop_containing_stmt (phi
))
6708 && l
->header
== gimple_bb (phi
))
6709 adjust_range_with_scev (&vr_result
, l
, phi
, lhs
);
6711 /* If we will end up with a (-INF, +INF) range, set it to
6712 VARYING. Same if the previous max value was invalid for
6713 the type and we end up with vr_result.min > vr_result.max. */
6714 if ((vrp_val_is_max (vr_result
.max
)
6715 && vrp_val_is_min (vr_result
.min
))
6716 || compare_values (vr_result
.min
,
6721 /* If the new range is different than the previous value, keep
6723 if (update_value_range (lhs
, &vr_result
))
6725 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
6727 fprintf (dump_file
, "Found new range for ");
6728 print_generic_expr (dump_file
, lhs
, 0);
6729 fprintf (dump_file
, ": ");
6730 dump_value_range (dump_file
, &vr_result
);
6731 fprintf (dump_file
, "\n\n");
6734 return SSA_PROP_INTERESTING
;
6737 /* Nothing changed, don't add outgoing edges. */
6738 return SSA_PROP_NOT_INTERESTING
;
6740 /* No match found. Set the LHS to VARYING. */
6742 set_value_range_to_varying (lhs_vr
);
6743 return SSA_PROP_VARYING
;
6746 /* Simplify boolean operations if the source is known
6747 to be already a boolean. */
6749 simplify_truth_ops_using_ranges (gimple_stmt_iterator
*gsi
, gimple stmt
)
6751 enum tree_code rhs_code
= gimple_assign_rhs_code (stmt
);
6756 bool need_conversion
;
6758 op0
= gimple_assign_rhs1 (stmt
);
6759 if (TYPE_PRECISION (TREE_TYPE (op0
)) != 1)
6761 if (TREE_CODE (op0
) != SSA_NAME
)
6763 vr
= get_value_range (op0
);
6765 val
= compare_range_with_value (GE_EXPR
, vr
, integer_zero_node
, &sop
);
6766 if (!val
|| !integer_onep (val
))
6769 val
= compare_range_with_value (LE_EXPR
, vr
, integer_one_node
, &sop
);
6770 if (!val
|| !integer_onep (val
))
6774 if (rhs_code
== TRUTH_NOT_EXPR
)
6777 op1
= build_int_cst (TREE_TYPE (op0
), 1);
6781 op1
= gimple_assign_rhs2 (stmt
);
6783 /* Reduce number of cases to handle. */
6784 if (is_gimple_min_invariant (op1
))
6786 /* Exclude anything that should have been already folded. */
6787 if (rhs_code
!= EQ_EXPR
6788 && rhs_code
!= NE_EXPR
6789 && rhs_code
!= TRUTH_XOR_EXPR
)
6792 if (!integer_zerop (op1
)
6793 && !integer_onep (op1
)
6794 && !integer_all_onesp (op1
))
6797 /* Limit the number of cases we have to consider. */
6798 if (rhs_code
== EQ_EXPR
)
6801 op1
= fold_unary (TRUTH_NOT_EXPR
, TREE_TYPE (op1
), op1
);
6806 /* Punt on A == B as there is no BIT_XNOR_EXPR. */
6807 if (rhs_code
== EQ_EXPR
)
6810 if (TYPE_PRECISION (TREE_TYPE (op1
)) != 1)
6812 vr
= get_value_range (op1
);
6813 val
= compare_range_with_value (GE_EXPR
, vr
, integer_zero_node
, &sop
);
6814 if (!val
|| !integer_onep (val
))
6817 val
= compare_range_with_value (LE_EXPR
, vr
, integer_one_node
, &sop
);
6818 if (!val
|| !integer_onep (val
))
6824 if (sop
&& issue_strict_overflow_warning (WARN_STRICT_OVERFLOW_MISC
))
6826 location_t location
;
6828 if (!gimple_has_location (stmt
))
6829 location
= input_location
;
6831 location
= gimple_location (stmt
);
6833 if (rhs_code
== TRUTH_AND_EXPR
|| rhs_code
== TRUTH_OR_EXPR
)
6834 warning_at (location
, OPT_Wstrict_overflow
,
6835 _("assuming signed overflow does not occur when "
6836 "simplifying && or || to & or |"));
6838 warning_at (location
, OPT_Wstrict_overflow
,
6839 _("assuming signed overflow does not occur when "
6840 "simplifying ==, != or ! to identity or ^"));
6844 !useless_type_conversion_p (TREE_TYPE (gimple_assign_lhs (stmt
)),
6847 /* Make sure to not sign-extend -1 as a boolean value. */
6849 && !TYPE_UNSIGNED (TREE_TYPE (op0
))
6850 && TYPE_PRECISION (TREE_TYPE (op0
)) == 1)
6855 case TRUTH_AND_EXPR
:
6856 rhs_code
= BIT_AND_EXPR
;
6859 rhs_code
= BIT_IOR_EXPR
;
6861 case TRUTH_XOR_EXPR
:
6863 if (integer_zerop (op1
))
6865 gimple_assign_set_rhs_with_ops (gsi
,
6866 need_conversion
? NOP_EXPR
: SSA_NAME
,
6868 update_stmt (gsi_stmt (*gsi
));
6872 rhs_code
= BIT_XOR_EXPR
;
6878 if (need_conversion
)
6881 gimple_assign_set_rhs_with_ops (gsi
, rhs_code
, op0
, op1
);
6882 update_stmt (gsi_stmt (*gsi
));
6886 /* Simplify a division or modulo operator to a right shift or
6887 bitwise and if the first operand is unsigned or is greater
6888 than zero and the second operand is an exact power of two. */
6891 simplify_div_or_mod_using_ranges (gimple stmt
)
6893 enum tree_code rhs_code
= gimple_assign_rhs_code (stmt
);
6895 tree op0
= gimple_assign_rhs1 (stmt
);
6896 tree op1
= gimple_assign_rhs2 (stmt
);
6897 value_range_t
*vr
= get_value_range (gimple_assign_rhs1 (stmt
));
6899 if (TYPE_UNSIGNED (TREE_TYPE (op0
)))
6901 val
= integer_one_node
;
6907 val
= compare_range_with_value (GE_EXPR
, vr
, integer_zero_node
, &sop
);
6911 && integer_onep (val
)
6912 && issue_strict_overflow_warning (WARN_STRICT_OVERFLOW_MISC
))
6914 location_t location
;
6916 if (!gimple_has_location (stmt
))
6917 location
= input_location
;
6919 location
= gimple_location (stmt
);
6920 warning_at (location
, OPT_Wstrict_overflow
,
6921 "assuming signed overflow does not occur when "
6922 "simplifying %</%> or %<%%%> to %<>>%> or %<&%>");
6926 if (val
&& integer_onep (val
))
6930 if (rhs_code
== TRUNC_DIV_EXPR
)
6932 t
= build_int_cst (integer_type_node
, tree_log2 (op1
));
6933 gimple_assign_set_rhs_code (stmt
, RSHIFT_EXPR
);
6934 gimple_assign_set_rhs1 (stmt
, op0
);
6935 gimple_assign_set_rhs2 (stmt
, t
);
6939 t
= build_int_cst (TREE_TYPE (op1
), 1);
6940 t
= int_const_binop (MINUS_EXPR
, op1
, t
);
6941 t
= fold_convert (TREE_TYPE (op0
), t
);
6943 gimple_assign_set_rhs_code (stmt
, BIT_AND_EXPR
);
6944 gimple_assign_set_rhs1 (stmt
, op0
);
6945 gimple_assign_set_rhs2 (stmt
, t
);
6955 /* If the operand to an ABS_EXPR is >= 0, then eliminate the
6956 ABS_EXPR. If the operand is <= 0, then simplify the
6957 ABS_EXPR into a NEGATE_EXPR. */
6960 simplify_abs_using_ranges (gimple stmt
)
6963 tree op
= gimple_assign_rhs1 (stmt
);
6964 tree type
= TREE_TYPE (op
);
6965 value_range_t
*vr
= get_value_range (op
);
6967 if (TYPE_UNSIGNED (type
))
6969 val
= integer_zero_node
;
6975 val
= compare_range_with_value (LE_EXPR
, vr
, integer_zero_node
, &sop
);
6979 val
= compare_range_with_value (GE_EXPR
, vr
, integer_zero_node
,
6984 if (integer_zerop (val
))
6985 val
= integer_one_node
;
6986 else if (integer_onep (val
))
6987 val
= integer_zero_node
;
6992 && (integer_onep (val
) || integer_zerop (val
)))
6994 if (sop
&& issue_strict_overflow_warning (WARN_STRICT_OVERFLOW_MISC
))
6996 location_t location
;
6998 if (!gimple_has_location (stmt
))
6999 location
= input_location
;
7001 location
= gimple_location (stmt
);
7002 warning_at (location
, OPT_Wstrict_overflow
,
7003 "assuming signed overflow does not occur when "
7004 "simplifying %<abs (X)%> to %<X%> or %<-X%>");
7007 gimple_assign_set_rhs1 (stmt
, op
);
7008 if (integer_onep (val
))
7009 gimple_assign_set_rhs_code (stmt
, NEGATE_EXPR
);
7011 gimple_assign_set_rhs_code (stmt
, SSA_NAME
);
7020 /* Optimize away redundant BIT_AND_EXPR and BIT_IOR_EXPR.
7021 If all the bits that are being cleared by & are already
7022 known to be zero from VR, or all the bits that are being
7023 set by | are already known to be one from VR, the bit
7024 operation is redundant. */
7027 simplify_bit_ops_using_ranges (gimple_stmt_iterator
*gsi
, gimple stmt
)
7029 tree op0
= gimple_assign_rhs1 (stmt
);
7030 tree op1
= gimple_assign_rhs2 (stmt
);
7031 tree op
= NULL_TREE
;
7032 value_range_t vr0
= { VR_UNDEFINED
, NULL_TREE
, NULL_TREE
, NULL
};
7033 value_range_t vr1
= { VR_UNDEFINED
, NULL_TREE
, NULL_TREE
, NULL
};
7034 double_int may_be_nonzero0
, may_be_nonzero1
;
7035 double_int must_be_nonzero0
, must_be_nonzero1
;
7038 if (TREE_CODE (op0
) == SSA_NAME
)
7039 vr0
= *(get_value_range (op0
));
7040 else if (is_gimple_min_invariant (op0
))
7041 set_value_range_to_value (&vr0
, op0
, NULL
);
7045 if (TREE_CODE (op1
) == SSA_NAME
)
7046 vr1
= *(get_value_range (op1
));
7047 else if (is_gimple_min_invariant (op1
))
7048 set_value_range_to_value (&vr1
, op1
, NULL
);
7052 if (!zero_nonzero_bits_from_vr (&vr0
, &may_be_nonzero0
, &must_be_nonzero0
))
7054 if (!zero_nonzero_bits_from_vr (&vr1
, &may_be_nonzero1
, &must_be_nonzero1
))
7057 switch (gimple_assign_rhs_code (stmt
))
7060 mask
= double_int_and_not (may_be_nonzero0
, must_be_nonzero1
);
7061 if (double_int_zero_p (mask
))
7066 mask
= double_int_and_not (may_be_nonzero1
, must_be_nonzero0
);
7067 if (double_int_zero_p (mask
))
7074 mask
= double_int_and_not (may_be_nonzero0
, must_be_nonzero1
);
7075 if (double_int_zero_p (mask
))
7080 mask
= double_int_and_not (may_be_nonzero1
, must_be_nonzero0
);
7081 if (double_int_zero_p (mask
))
7091 if (op
== NULL_TREE
)
7094 gimple_assign_set_rhs_with_ops (gsi
, TREE_CODE (op
), op
, NULL
);
7095 update_stmt (gsi_stmt (*gsi
));
7099 /* We are comparing trees OP0 and OP1 using COND_CODE. OP0 has
7100 a known value range VR.
7102 If there is one and only one value which will satisfy the
7103 conditional, then return that value. Else return NULL. */
7106 test_for_singularity (enum tree_code cond_code
, tree op0
,
7107 tree op1
, value_range_t
*vr
)
7112 /* Extract minimum/maximum values which satisfy the
7113 the conditional as it was written. */
7114 if (cond_code
== LE_EXPR
|| cond_code
== LT_EXPR
)
7116 /* This should not be negative infinity; there is no overflow
7118 min
= TYPE_MIN_VALUE (TREE_TYPE (op0
));
7121 if (cond_code
== LT_EXPR
&& !is_overflow_infinity (max
))
7123 tree one
= build_int_cst (TREE_TYPE (op0
), 1);
7124 max
= fold_build2 (MINUS_EXPR
, TREE_TYPE (op0
), max
, one
);
7126 TREE_NO_WARNING (max
) = 1;
7129 else if (cond_code
== GE_EXPR
|| cond_code
== GT_EXPR
)
7131 /* This should not be positive infinity; there is no overflow
7133 max
= TYPE_MAX_VALUE (TREE_TYPE (op0
));
7136 if (cond_code
== GT_EXPR
&& !is_overflow_infinity (min
))
7138 tree one
= build_int_cst (TREE_TYPE (op0
), 1);
7139 min
= fold_build2 (PLUS_EXPR
, TREE_TYPE (op0
), min
, one
);
7141 TREE_NO_WARNING (min
) = 1;
7145 /* Now refine the minimum and maximum values using any
7146 value range information we have for op0. */
7149 if (compare_values (vr
->min
, min
) == 1)
7151 if (compare_values (vr
->max
, max
) == -1)
7154 /* If the new min/max values have converged to a single value,
7155 then there is only one value which can satisfy the condition,
7156 return that value. */
7157 if (operand_equal_p (min
, max
, 0) && is_gimple_min_invariant (min
))
7163 /* Simplify a conditional using a relational operator to an equality
7164 test if the range information indicates only one value can satisfy
7165 the original conditional. */
7168 simplify_cond_using_ranges (gimple stmt
)
7170 tree op0
= gimple_cond_lhs (stmt
);
7171 tree op1
= gimple_cond_rhs (stmt
);
7172 enum tree_code cond_code
= gimple_cond_code (stmt
);
7174 if (cond_code
!= NE_EXPR
7175 && cond_code
!= EQ_EXPR
7176 && TREE_CODE (op0
) == SSA_NAME
7177 && INTEGRAL_TYPE_P (TREE_TYPE (op0
))
7178 && is_gimple_min_invariant (op1
))
7180 value_range_t
*vr
= get_value_range (op0
);
7182 /* If we have range information for OP0, then we might be
7183 able to simplify this conditional. */
7184 if (vr
->type
== VR_RANGE
)
7186 tree new_tree
= test_for_singularity (cond_code
, op0
, op1
, vr
);
7192 fprintf (dump_file
, "Simplified relational ");
7193 print_gimple_stmt (dump_file
, stmt
, 0, 0);
7194 fprintf (dump_file
, " into ");
7197 gimple_cond_set_code (stmt
, EQ_EXPR
);
7198 gimple_cond_set_lhs (stmt
, op0
);
7199 gimple_cond_set_rhs (stmt
, new_tree
);
7205 print_gimple_stmt (dump_file
, stmt
, 0, 0);
7206 fprintf (dump_file
, "\n");
7212 /* Try again after inverting the condition. We only deal
7213 with integral types here, so no need to worry about
7214 issues with inverting FP comparisons. */
7215 cond_code
= invert_tree_comparison (cond_code
, false);
7216 new_tree
= test_for_singularity (cond_code
, op0
, op1
, vr
);
7222 fprintf (dump_file
, "Simplified relational ");
7223 print_gimple_stmt (dump_file
, stmt
, 0, 0);
7224 fprintf (dump_file
, " into ");
7227 gimple_cond_set_code (stmt
, NE_EXPR
);
7228 gimple_cond_set_lhs (stmt
, op0
);
7229 gimple_cond_set_rhs (stmt
, new_tree
);
7235 print_gimple_stmt (dump_file
, stmt
, 0, 0);
7236 fprintf (dump_file
, "\n");
7247 /* Simplify a switch statement using the value range of the switch
7251 simplify_switch_using_ranges (gimple stmt
)
7253 tree op
= gimple_switch_index (stmt
);
7258 size_t i
= 0, j
= 0, n
, n2
;
7262 if (TREE_CODE (op
) == SSA_NAME
)
7264 vr
= get_value_range (op
);
7266 /* We can only handle integer ranges. */
7267 if (vr
->type
!= VR_RANGE
7268 || symbolic_range_p (vr
))
7271 /* Find case label for min/max of the value range. */
7272 take_default
= !find_case_label_range (stmt
, vr
->min
, vr
->max
, &i
, &j
);
7274 else if (TREE_CODE (op
) == INTEGER_CST
)
7276 take_default
= !find_case_label_index (stmt
, 1, op
, &i
);
7290 n
= gimple_switch_num_labels (stmt
);
7292 /* Bail out if this is just all edges taken. */
7298 /* Build a new vector of taken case labels. */
7299 vec2
= make_tree_vec (j
- i
+ 1 + (int)take_default
);
7302 /* Add the default edge, if necessary. */
7304 TREE_VEC_ELT (vec2
, n2
++) = gimple_switch_default_label (stmt
);
7306 for (; i
<= j
; ++i
, ++n2
)
7307 TREE_VEC_ELT (vec2
, n2
) = gimple_switch_label (stmt
, i
);
7309 /* Mark needed edges. */
7310 for (i
= 0; i
< n2
; ++i
)
7312 e
= find_edge (gimple_bb (stmt
),
7313 label_to_block (CASE_LABEL (TREE_VEC_ELT (vec2
, i
))));
7314 e
->aux
= (void *)-1;
7317 /* Queue not needed edges for later removal. */
7318 FOR_EACH_EDGE (e
, ei
, gimple_bb (stmt
)->succs
)
7320 if (e
->aux
== (void *)-1)
7326 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
7328 fprintf (dump_file
, "removing unreachable case label\n");
7330 VEC_safe_push (edge
, heap
, to_remove_edges
, e
);
7331 e
->flags
&= ~EDGE_EXECUTABLE
;
7334 /* And queue an update for the stmt. */
7337 VEC_safe_push (switch_update
, heap
, to_update_switch_stmts
, &su
);
7341 /* Simplify STMT using ranges if possible. */
7344 simplify_stmt_using_ranges (gimple_stmt_iterator
*gsi
)
7346 gimple stmt
= gsi_stmt (*gsi
);
7347 if (is_gimple_assign (stmt
))
7349 enum tree_code rhs_code
= gimple_assign_rhs_code (stmt
);
7355 case TRUTH_NOT_EXPR
:
7356 case TRUTH_AND_EXPR
:
7358 case TRUTH_XOR_EXPR
:
7359 /* Transform EQ_EXPR, NE_EXPR, TRUTH_NOT_EXPR into BIT_XOR_EXPR
7360 or identity if the RHS is zero or one, and the LHS are known
7361 to be boolean values. Transform all TRUTH_*_EXPR into
7362 BIT_*_EXPR if both arguments are known to be boolean values. */
7363 if (INTEGRAL_TYPE_P (TREE_TYPE (gimple_assign_rhs1 (stmt
))))
7364 return simplify_truth_ops_using_ranges (gsi
, stmt
);
7367 /* Transform TRUNC_DIV_EXPR and TRUNC_MOD_EXPR into RSHIFT_EXPR
7368 and BIT_AND_EXPR respectively if the first operand is greater
7369 than zero and the second operand is an exact power of two. */
7370 case TRUNC_DIV_EXPR
:
7371 case TRUNC_MOD_EXPR
:
7372 if (INTEGRAL_TYPE_P (TREE_TYPE (gimple_assign_rhs1 (stmt
)))
7373 && integer_pow2p (gimple_assign_rhs2 (stmt
)))
7374 return simplify_div_or_mod_using_ranges (stmt
);
7377 /* Transform ABS (X) into X or -X as appropriate. */
7379 if (TREE_CODE (gimple_assign_rhs1 (stmt
)) == SSA_NAME
7380 && INTEGRAL_TYPE_P (TREE_TYPE (gimple_assign_rhs1 (stmt
))))
7381 return simplify_abs_using_ranges (stmt
);
7386 /* Optimize away BIT_AND_EXPR and BIT_IOR_EXPR
7387 if all the bits being cleared are already cleared or
7388 all the bits being set are already set. */
7389 if (INTEGRAL_TYPE_P (TREE_TYPE (gimple_assign_rhs1 (stmt
))))
7390 return simplify_bit_ops_using_ranges (gsi
, stmt
);
7397 else if (gimple_code (stmt
) == GIMPLE_COND
)
7398 return simplify_cond_using_ranges (stmt
);
7399 else if (gimple_code (stmt
) == GIMPLE_SWITCH
)
7400 return simplify_switch_using_ranges (stmt
);
7405 /* If the statement pointed by SI has a predicate whose value can be
7406 computed using the value range information computed by VRP, compute
7407 its value and return true. Otherwise, return false. */
7410 fold_predicate_in (gimple_stmt_iterator
*si
)
7412 bool assignment_p
= false;
7414 gimple stmt
= gsi_stmt (*si
);
7416 if (is_gimple_assign (stmt
)
7417 && TREE_CODE_CLASS (gimple_assign_rhs_code (stmt
)) == tcc_comparison
)
7419 assignment_p
= true;
7420 val
= vrp_evaluate_conditional (gimple_assign_rhs_code (stmt
),
7421 gimple_assign_rhs1 (stmt
),
7422 gimple_assign_rhs2 (stmt
),
7425 else if (gimple_code (stmt
) == GIMPLE_COND
)
7426 val
= vrp_evaluate_conditional (gimple_cond_code (stmt
),
7427 gimple_cond_lhs (stmt
),
7428 gimple_cond_rhs (stmt
),
7436 val
= fold_convert (gimple_expr_type (stmt
), val
);
7440 fprintf (dump_file
, "Folding predicate ");
7441 print_gimple_expr (dump_file
, stmt
, 0, 0);
7442 fprintf (dump_file
, " to ");
7443 print_generic_expr (dump_file
, val
, 0);
7444 fprintf (dump_file
, "\n");
7447 if (is_gimple_assign (stmt
))
7448 gimple_assign_set_rhs_from_tree (si
, val
);
7451 gcc_assert (gimple_code (stmt
) == GIMPLE_COND
);
7452 if (integer_zerop (val
))
7453 gimple_cond_make_false (stmt
);
7454 else if (integer_onep (val
))
7455 gimple_cond_make_true (stmt
);
7466 /* Callback for substitute_and_fold folding the stmt at *SI. */
7469 vrp_fold_stmt (gimple_stmt_iterator
*si
)
7471 if (fold_predicate_in (si
))
7474 return simplify_stmt_using_ranges (si
);
7477 /* Stack of dest,src equivalency pairs that need to be restored after
7478 each attempt to thread a block's incoming edge to an outgoing edge.
7480 A NULL entry is used to mark the end of pairs which need to be
7482 static VEC(tree
,heap
) *stack
;
7484 /* A trivial wrapper so that we can present the generic jump threading
7485 code with a simple API for simplifying statements. STMT is the
7486 statement we want to simplify, WITHIN_STMT provides the location
7487 for any overflow warnings. */
7490 simplify_stmt_for_jump_threading (gimple stmt
, gimple within_stmt
)
7492 /* We only use VRP information to simplify conditionals. This is
7493 overly conservative, but it's unclear if doing more would be
7494 worth the compile time cost. */
7495 if (gimple_code (stmt
) != GIMPLE_COND
)
7498 return vrp_evaluate_conditional (gimple_cond_code (stmt
),
7499 gimple_cond_lhs (stmt
),
7500 gimple_cond_rhs (stmt
), within_stmt
);
7503 /* Blocks which have more than one predecessor and more than
7504 one successor present jump threading opportunities, i.e.,
7505 when the block is reached from a specific predecessor, we
7506 may be able to determine which of the outgoing edges will
7507 be traversed. When this optimization applies, we are able
7508 to avoid conditionals at runtime and we may expose secondary
7509 optimization opportunities.
7511 This routine is effectively a driver for the generic jump
7512 threading code. It basically just presents the generic code
7513 with edges that may be suitable for jump threading.
7515 Unlike DOM, we do not iterate VRP if jump threading was successful.
7516 While iterating may expose new opportunities for VRP, it is expected
7517 those opportunities would be very limited and the compile time cost
7518 to expose those opportunities would be significant.
7520 As jump threading opportunities are discovered, they are registered
7521 for later realization. */
7524 identify_jump_threads (void)
7531 /* Ugh. When substituting values earlier in this pass we can
7532 wipe the dominance information. So rebuild the dominator
7533 information as we need it within the jump threading code. */
7534 calculate_dominance_info (CDI_DOMINATORS
);
7536 /* We do not allow VRP information to be used for jump threading
7537 across a back edge in the CFG. Otherwise it becomes too
7538 difficult to avoid eliminating loop exit tests. Of course
7539 EDGE_DFS_BACK is not accurate at this time so we have to
7541 mark_dfs_back_edges ();
7543 /* Do not thread across edges we are about to remove. Just marking
7544 them as EDGE_DFS_BACK will do. */
7545 FOR_EACH_VEC_ELT (edge
, to_remove_edges
, i
, e
)
7546 e
->flags
|= EDGE_DFS_BACK
;
7548 /* Allocate our unwinder stack to unwind any temporary equivalences
7549 that might be recorded. */
7550 stack
= VEC_alloc (tree
, heap
, 20);
7552 /* To avoid lots of silly node creation, we create a single
7553 conditional and just modify it in-place when attempting to
7555 dummy
= gimple_build_cond (EQ_EXPR
,
7556 integer_zero_node
, integer_zero_node
,
7559 /* Walk through all the blocks finding those which present a
7560 potential jump threading opportunity. We could set this up
7561 as a dominator walker and record data during the walk, but
7562 I doubt it's worth the effort for the classes of jump
7563 threading opportunities we are trying to identify at this
7564 point in compilation. */
7569 /* If the generic jump threading code does not find this block
7570 interesting, then there is nothing to do. */
7571 if (! potentially_threadable_block (bb
))
7574 /* We only care about blocks ending in a COND_EXPR. While there
7575 may be some value in handling SWITCH_EXPR here, I doubt it's
7576 terribly important. */
7577 last
= gsi_stmt (gsi_last_bb (bb
));
7579 /* We're basically looking for a switch or any kind of conditional with
7580 integral or pointer type arguments. Note the type of the second
7581 argument will be the same as the first argument, so no need to
7582 check it explicitly. */
7583 if (gimple_code (last
) == GIMPLE_SWITCH
7584 || (gimple_code (last
) == GIMPLE_COND
7585 && TREE_CODE (gimple_cond_lhs (last
)) == SSA_NAME
7586 && (INTEGRAL_TYPE_P (TREE_TYPE (gimple_cond_lhs (last
)))
7587 || POINTER_TYPE_P (TREE_TYPE (gimple_cond_lhs (last
))))
7588 && (TREE_CODE (gimple_cond_rhs (last
)) == SSA_NAME
7589 || is_gimple_min_invariant (gimple_cond_rhs (last
)))))
7593 /* We've got a block with multiple predecessors and multiple
7594 successors which also ends in a suitable conditional or
7595 switch statement. For each predecessor, see if we can thread
7596 it to a specific successor. */
7597 FOR_EACH_EDGE (e
, ei
, bb
->preds
)
7599 /* Do not thread across back edges or abnormal edges
7601 if (e
->flags
& (EDGE_DFS_BACK
| EDGE_COMPLEX
))
7604 thread_across_edge (dummy
, e
, true, &stack
,
7605 simplify_stmt_for_jump_threading
);
7610 /* We do not actually update the CFG or SSA graphs at this point as
7611 ASSERT_EXPRs are still in the IL and cfg cleanup code does not yet
7612 handle ASSERT_EXPRs gracefully. */
7615 /* We identified all the jump threading opportunities earlier, but could
7616 not transform the CFG at that time. This routine transforms the
7617 CFG and arranges for the dominator tree to be rebuilt if necessary.
7619 Note the SSA graph update will occur during the normal TODO
7620 processing by the pass manager. */
7622 finalize_jump_threads (void)
7624 thread_through_all_blocks (false);
7625 VEC_free (tree
, heap
, stack
);
7629 /* Traverse all the blocks folding conditionals with known ranges. */
7635 unsigned num
= num_ssa_names
;
7639 fprintf (dump_file
, "\nValue ranges after VRP:\n\n");
7640 dump_all_value_ranges (dump_file
);
7641 fprintf (dump_file
, "\n");
7644 substitute_and_fold (op_with_constant_singleton_value_range
,
7645 vrp_fold_stmt
, false);
7647 if (warn_array_bounds
)
7648 check_all_array_refs ();
7650 /* We must identify jump threading opportunities before we release
7651 the datastructures built by VRP. */
7652 identify_jump_threads ();
7654 /* Free allocated memory. */
7655 for (i
= 0; i
< num
; i
++)
7658 BITMAP_FREE (vr_value
[i
]->equiv
);
7663 free (vr_phi_edge_counts
);
7665 /* So that we can distinguish between VRP data being available
7666 and not available. */
7668 vr_phi_edge_counts
= NULL
;
7672 /* Main entry point to VRP (Value Range Propagation). This pass is
7673 loosely based on J. R. C. Patterson, ``Accurate Static Branch
7674 Prediction by Value Range Propagation,'' in SIGPLAN Conference on
7675 Programming Language Design and Implementation, pp. 67-78, 1995.
7676 Also available at http://citeseer.ist.psu.edu/patterson95accurate.html
7678 This is essentially an SSA-CCP pass modified to deal with ranges
7679 instead of constants.
7681 While propagating ranges, we may find that two or more SSA name
7682 have equivalent, though distinct ranges. For instance,
7685 2 p_4 = ASSERT_EXPR <p_3, p_3 != 0>
7687 4 p_5 = ASSERT_EXPR <p_4, p_4 == q_2>;
7691 In the code above, pointer p_5 has range [q_2, q_2], but from the
7692 code we can also determine that p_5 cannot be NULL and, if q_2 had
7693 a non-varying range, p_5's range should also be compatible with it.
7695 These equivalences are created by two expressions: ASSERT_EXPR and
7696 copy operations. Since p_5 is an assertion on p_4, and p_4 was the
7697 result of another assertion, then we can use the fact that p_5 and
7698 p_4 are equivalent when evaluating p_5's range.
7700 Together with value ranges, we also propagate these equivalences
7701 between names so that we can take advantage of information from
7702 multiple ranges when doing final replacement. Note that this
7703 equivalency relation is transitive but not symmetric.
7705 In the example above, p_5 is equivalent to p_4, q_2 and p_3, but we
7706 cannot assert that q_2 is equivalent to p_5 because q_2 may be used
7707 in contexts where that assertion does not hold (e.g., in line 6).
7709 TODO, the main difference between this pass and Patterson's is that
7710 we do not propagate edge probabilities. We only compute whether
7711 edges can be taken or not. That is, instead of having a spectrum
7712 of jump probabilities between 0 and 1, we only deal with 0, 1 and
7713 DON'T KNOW. In the future, it may be worthwhile to propagate
7714 probabilities to aid branch prediction. */
7723 loop_optimizer_init (LOOPS_NORMAL
| LOOPS_HAVE_RECORDED_EXITS
);
7724 rewrite_into_loop_closed_ssa (NULL
, TODO_update_ssa
);
7727 /* Estimate number of iterations - but do not use undefined behavior
7728 for this. We can't do this lazily as other functions may compute
7729 this using undefined behavior. */
7730 free_numbers_of_iterations_estimates ();
7731 estimate_numbers_of_iterations (false);
7733 insert_range_assertions ();
7735 to_remove_edges
= VEC_alloc (edge
, heap
, 10);
7736 to_update_switch_stmts
= VEC_alloc (switch_update
, heap
, 5);
7737 threadedge_initialize_values ();
7740 ssa_propagate (vrp_visit_stmt
, vrp_visit_phi_node
);
7743 /* ASSERT_EXPRs must be removed before finalizing jump threads
7744 as finalizing jump threads calls the CFG cleanup code which
7745 does not properly handle ASSERT_EXPRs. */
7746 remove_range_assertions ();
7748 /* If we exposed any new variables, go ahead and put them into
7749 SSA form now, before we handle jump threading. This simplifies
7750 interactions between rewriting of _DECL nodes into SSA form
7751 and rewriting SSA_NAME nodes into SSA form after block
7752 duplication and CFG manipulation. */
7753 update_ssa (TODO_update_ssa
);
7755 finalize_jump_threads ();
7757 /* Remove dead edges from SWITCH_EXPR optimization. This leaves the
7758 CFG in a broken state and requires a cfg_cleanup run. */
7759 FOR_EACH_VEC_ELT (edge
, to_remove_edges
, i
, e
)
7761 /* Update SWITCH_EXPR case label vector. */
7762 FOR_EACH_VEC_ELT (switch_update
, to_update_switch_stmts
, i
, su
)
7765 size_t n
= TREE_VEC_LENGTH (su
->vec
);
7767 gimple_switch_set_num_labels (su
->stmt
, n
);
7768 for (j
= 0; j
< n
; j
++)
7769 gimple_switch_set_label (su
->stmt
, j
, TREE_VEC_ELT (su
->vec
, j
));
7770 /* As we may have replaced the default label with a regular one
7771 make sure to make it a real default label again. This ensures
7772 optimal expansion. */
7773 label
= gimple_switch_default_label (su
->stmt
);
7774 CASE_LOW (label
) = NULL_TREE
;
7775 CASE_HIGH (label
) = NULL_TREE
;
7778 if (VEC_length (edge
, to_remove_edges
) > 0)
7779 free_dominance_info (CDI_DOMINATORS
);
7781 VEC_free (edge
, heap
, to_remove_edges
);
7782 VEC_free (switch_update
, heap
, to_update_switch_stmts
);
7783 threadedge_finalize_values ();
7786 loop_optimizer_finalize ();
7793 return flag_tree_vrp
!= 0;
7796 struct gimple_opt_pass pass_vrp
=
7801 gate_vrp
, /* gate */
7802 execute_vrp
, /* execute */
7805 0, /* static_pass_number */
7806 TV_TREE_VRP
, /* tv_id */
7807 PROP_ssa
, /* properties_required */
7808 0, /* properties_provided */
7809 0, /* properties_destroyed */
7810 0, /* todo_flags_start */
7816 | TODO_ggc_collect
/* todo_flags_finish */