1 /* Support routines for Value Range Propagation (VRP).
2 Copyright (C) 2005, 2006, 2007, 2008 Free Software Foundation, Inc.
3 Contributed by Diego Novillo <dnovillo@redhat.com>.
5 This file is part of GCC.
7 GCC is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 3, or (at your option)
12 GCC is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with GCC; see the file COPYING3. If not see
19 <http://www.gnu.org/licenses/>. */
23 #include "coretypes.h"
28 #include "basic-block.h"
29 #include "tree-flow.h"
30 #include "tree-pass.h"
31 #include "tree-dump.h"
33 #include "diagnostic.h"
37 #include "tree-scalar-evolution.h"
38 #include "tree-ssa-propagate.h"
39 #include "tree-chrec.h"
42 /* Set of SSA names found live during the RPO traversal of the function
43 for still active basic-blocks. */
46 /* Return true if the SSA name NAME is live on the edge E. */
49 live_on_edge (edge e
, tree name
)
51 return (live
[e
->dest
->index
]
52 && TEST_BIT (live
[e
->dest
->index
], SSA_NAME_VERSION (name
)));
55 /* Local functions. */
56 static int compare_values (tree val1
, tree val2
);
57 static int compare_values_warnv (tree val1
, tree val2
, bool *);
58 static void vrp_meet (value_range_t
*, value_range_t
*);
59 static tree
vrp_evaluate_conditional_warnv_with_ops (enum tree_code
,
60 tree
, tree
, bool, bool *);
62 /* Location information for ASSERT_EXPRs. Each instance of this
63 structure describes an ASSERT_EXPR for an SSA name. Since a single
64 SSA name may have more than one assertion associated with it, these
65 locations are kept in a linked list attached to the corresponding
69 /* Basic block where the assertion would be inserted. */
72 /* Some assertions need to be inserted on an edge (e.g., assertions
73 generated by COND_EXPRs). In those cases, BB will be NULL. */
76 /* Pointer to the statement that generated this assertion. */
77 gimple_stmt_iterator si
;
79 /* Predicate code for the ASSERT_EXPR. Must be COMPARISON_CLASS_P. */
80 enum tree_code comp_code
;
82 /* Value being compared against. */
85 /* Expression to compare. */
88 /* Next node in the linked list. */
89 struct assert_locus_d
*next
;
92 typedef struct assert_locus_d
*assert_locus_t
;
94 /* If bit I is present, it means that SSA name N_i has a list of
95 assertions that should be inserted in the IL. */
96 static bitmap need_assert_for
;
98 /* Array of locations lists where to insert assertions. ASSERTS_FOR[I]
99 holds a list of ASSERT_LOCUS_T nodes that describe where
100 ASSERT_EXPRs for SSA name N_I should be inserted. */
101 static assert_locus_t
*asserts_for
;
103 /* Value range array. After propagation, VR_VALUE[I] holds the range
104 of values that SSA name N_I may take. */
105 static value_range_t
**vr_value
;
107 /* For a PHI node which sets SSA name N_I, VR_COUNTS[I] holds the
108 number of executable edges we saw the last time we visited the
110 static int *vr_phi_edge_counts
;
117 static VEC (edge
, heap
) *to_remove_edges
;
118 DEF_VEC_O(switch_update
);
119 DEF_VEC_ALLOC_O(switch_update
, heap
);
120 static VEC (switch_update
, heap
) *to_update_switch_stmts
;
123 /* Return the maximum value for TYPEs base type. */
126 vrp_val_max (const_tree type
)
128 if (!INTEGRAL_TYPE_P (type
))
131 /* For integer sub-types the values for the base type are relevant. */
132 if (TREE_TYPE (type
))
133 type
= TREE_TYPE (type
);
135 return TYPE_MAX_VALUE (type
);
138 /* Return the minimum value for TYPEs base type. */
141 vrp_val_min (const_tree type
)
143 if (!INTEGRAL_TYPE_P (type
))
146 /* For integer sub-types the values for the base type are relevant. */
147 if (TREE_TYPE (type
))
148 type
= TREE_TYPE (type
);
150 return TYPE_MIN_VALUE (type
);
153 /* Return whether VAL is equal to the maximum value of its type. This
154 will be true for a positive overflow infinity. We can't do a
155 simple equality comparison with TYPE_MAX_VALUE because C typedefs
156 and Ada subtypes can produce types whose TYPE_MAX_VALUE is not ==
157 to the integer constant with the same value in the type. */
160 vrp_val_is_max (const_tree val
)
162 tree type_max
= vrp_val_max (TREE_TYPE (val
));
163 return (val
== type_max
164 || (type_max
!= NULL_TREE
165 && operand_equal_p (val
, type_max
, 0)));
168 /* Return whether VAL is equal to the minimum value of its type. This
169 will be true for a negative overflow infinity. */
172 vrp_val_is_min (const_tree val
)
174 tree type_min
= vrp_val_min (TREE_TYPE (val
));
175 return (val
== type_min
176 || (type_min
!= NULL_TREE
177 && operand_equal_p (val
, type_min
, 0)));
181 /* Return whether TYPE should use an overflow infinity distinct from
182 TYPE_{MIN,MAX}_VALUE. We use an overflow infinity value to
183 represent a signed overflow during VRP computations. An infinity
184 is distinct from a half-range, which will go from some number to
185 TYPE_{MIN,MAX}_VALUE. */
188 needs_overflow_infinity (const_tree type
)
190 return (INTEGRAL_TYPE_P (type
)
191 && !TYPE_OVERFLOW_WRAPS (type
)
192 /* Integer sub-types never overflow as they are never
193 operands of arithmetic operators. */
194 && !(TREE_TYPE (type
) && TREE_TYPE (type
) != type
));
197 /* Return whether TYPE can support our overflow infinity
198 representation: we use the TREE_OVERFLOW flag, which only exists
199 for constants. If TYPE doesn't support this, we don't optimize
200 cases which would require signed overflow--we drop them to
204 supports_overflow_infinity (const_tree type
)
206 tree min
= vrp_val_min (type
), max
= vrp_val_max (type
);
207 #ifdef ENABLE_CHECKING
208 gcc_assert (needs_overflow_infinity (type
));
210 return (min
!= NULL_TREE
211 && CONSTANT_CLASS_P (min
)
213 && CONSTANT_CLASS_P (max
));
216 /* VAL is the maximum or minimum value of a type. Return a
217 corresponding overflow infinity. */
220 make_overflow_infinity (tree val
)
222 #ifdef ENABLE_CHECKING
223 gcc_assert (val
!= NULL_TREE
&& CONSTANT_CLASS_P (val
));
225 val
= copy_node (val
);
226 TREE_OVERFLOW (val
) = 1;
230 /* Return a negative overflow infinity for TYPE. */
233 negative_overflow_infinity (tree type
)
235 #ifdef ENABLE_CHECKING
236 gcc_assert (supports_overflow_infinity (type
));
238 return make_overflow_infinity (vrp_val_min (type
));
241 /* Return a positive overflow infinity for TYPE. */
244 positive_overflow_infinity (tree type
)
246 #ifdef ENABLE_CHECKING
247 gcc_assert (supports_overflow_infinity (type
));
249 return make_overflow_infinity (vrp_val_max (type
));
252 /* Return whether VAL is a negative overflow infinity. */
255 is_negative_overflow_infinity (const_tree val
)
257 return (needs_overflow_infinity (TREE_TYPE (val
))
258 && CONSTANT_CLASS_P (val
)
259 && TREE_OVERFLOW (val
)
260 && vrp_val_is_min (val
));
263 /* Return whether VAL is a positive overflow infinity. */
266 is_positive_overflow_infinity (const_tree val
)
268 return (needs_overflow_infinity (TREE_TYPE (val
))
269 && CONSTANT_CLASS_P (val
)
270 && TREE_OVERFLOW (val
)
271 && vrp_val_is_max (val
));
274 /* Return whether VAL is a positive or negative overflow infinity. */
277 is_overflow_infinity (const_tree val
)
279 return (needs_overflow_infinity (TREE_TYPE (val
))
280 && CONSTANT_CLASS_P (val
)
281 && TREE_OVERFLOW (val
)
282 && (vrp_val_is_min (val
) || vrp_val_is_max (val
)));
285 /* Return whether STMT has a constant rhs that is_overflow_infinity. */
288 stmt_overflow_infinity (gimple stmt
)
290 if (is_gimple_assign (stmt
)
291 && get_gimple_rhs_class (gimple_assign_rhs_code (stmt
)) ==
293 return is_overflow_infinity (gimple_assign_rhs1 (stmt
));
297 /* If VAL is now an overflow infinity, return VAL. Otherwise, return
298 the same value with TREE_OVERFLOW clear. This can be used to avoid
299 confusing a regular value with an overflow value. */
302 avoid_overflow_infinity (tree val
)
304 if (!is_overflow_infinity (val
))
307 if (vrp_val_is_max (val
))
308 return vrp_val_max (TREE_TYPE (val
));
311 #ifdef ENABLE_CHECKING
312 gcc_assert (vrp_val_is_min (val
));
314 return vrp_val_min (TREE_TYPE (val
));
319 /* Return true if ARG is marked with the nonnull attribute in the
320 current function signature. */
323 nonnull_arg_p (const_tree arg
)
325 tree t
, attrs
, fntype
;
326 unsigned HOST_WIDE_INT arg_num
;
328 gcc_assert (TREE_CODE (arg
) == PARM_DECL
&& POINTER_TYPE_P (TREE_TYPE (arg
)));
330 /* The static chain decl is always non null. */
331 if (arg
== cfun
->static_chain_decl
)
334 fntype
= TREE_TYPE (current_function_decl
);
335 attrs
= lookup_attribute ("nonnull", TYPE_ATTRIBUTES (fntype
));
337 /* If "nonnull" wasn't specified, we know nothing about the argument. */
338 if (attrs
== NULL_TREE
)
341 /* If "nonnull" applies to all the arguments, then ARG is non-null. */
342 if (TREE_VALUE (attrs
) == NULL_TREE
)
345 /* Get the position number for ARG in the function signature. */
346 for (arg_num
= 1, t
= DECL_ARGUMENTS (current_function_decl
);
348 t
= TREE_CHAIN (t
), arg_num
++)
354 gcc_assert (t
== arg
);
356 /* Now see if ARG_NUM is mentioned in the nonnull list. */
357 for (t
= TREE_VALUE (attrs
); t
; t
= TREE_CHAIN (t
))
359 if (compare_tree_int (TREE_VALUE (t
), arg_num
) == 0)
367 /* Set value range VR to VR_VARYING. */
370 set_value_range_to_varying (value_range_t
*vr
)
372 vr
->type
= VR_VARYING
;
373 vr
->min
= vr
->max
= NULL_TREE
;
375 bitmap_clear (vr
->equiv
);
379 /* Set value range VR to {T, MIN, MAX, EQUIV}. */
382 set_value_range (value_range_t
*vr
, enum value_range_type t
, tree min
,
383 tree max
, bitmap equiv
)
385 #if defined ENABLE_CHECKING
386 /* Check the validity of the range. */
387 if (t
== VR_RANGE
|| t
== VR_ANTI_RANGE
)
391 gcc_assert (min
&& max
);
393 if (INTEGRAL_TYPE_P (TREE_TYPE (min
)) && t
== VR_ANTI_RANGE
)
394 gcc_assert (!vrp_val_is_min (min
) || !vrp_val_is_max (max
));
396 cmp
= compare_values (min
, max
);
397 gcc_assert (cmp
== 0 || cmp
== -1 || cmp
== -2);
399 if (needs_overflow_infinity (TREE_TYPE (min
)))
400 gcc_assert (!is_overflow_infinity (min
)
401 || !is_overflow_infinity (max
));
404 if (t
== VR_UNDEFINED
|| t
== VR_VARYING
)
405 gcc_assert (min
== NULL_TREE
&& max
== NULL_TREE
);
407 if (t
== VR_UNDEFINED
|| t
== VR_VARYING
)
408 gcc_assert (equiv
== NULL
|| bitmap_empty_p (equiv
));
415 /* Since updating the equivalence set involves deep copying the
416 bitmaps, only do it if absolutely necessary. */
417 if (vr
->equiv
== NULL
419 vr
->equiv
= BITMAP_ALLOC (NULL
);
421 if (equiv
!= vr
->equiv
)
423 if (equiv
&& !bitmap_empty_p (equiv
))
424 bitmap_copy (vr
->equiv
, equiv
);
426 bitmap_clear (vr
->equiv
);
431 /* Set value range VR to the canonical form of {T, MIN, MAX, EQUIV}.
432 This means adjusting T, MIN and MAX representing the case of a
433 wrapping range with MAX < MIN covering [MIN, type_max] U [type_min, MAX]
434 as anti-rage ~[MAX+1, MIN-1]. Likewise for wrapping anti-ranges.
435 In corner cases where MAX+1 or MIN-1 wraps this will fall back
437 This routine exists to ease canonicalization in the case where we
438 extract ranges from var + CST op limit. */
441 set_and_canonicalize_value_range (value_range_t
*vr
, enum value_range_type t
,
442 tree min
, tree max
, bitmap equiv
)
444 /* Nothing to canonicalize for symbolic or unknown or varying ranges. */
446 && t
!= VR_ANTI_RANGE
)
447 || TREE_CODE (min
) != INTEGER_CST
448 || TREE_CODE (max
) != INTEGER_CST
)
450 set_value_range (vr
, t
, min
, max
, equiv
);
454 /* Wrong order for min and max, to swap them and the VR type we need
456 if (tree_int_cst_lt (max
, min
))
458 tree one
= build_int_cst (TREE_TYPE (min
), 1);
459 tree tmp
= int_const_binop (PLUS_EXPR
, max
, one
, 0);
460 max
= int_const_binop (MINUS_EXPR
, min
, one
, 0);
463 /* There's one corner case, if we had [C+1, C] before we now have
464 that again. But this represents an empty value range, so drop
465 to varying in this case. */
466 if (tree_int_cst_lt (max
, min
))
468 set_value_range_to_varying (vr
);
472 t
= t
== VR_RANGE
? VR_ANTI_RANGE
: VR_RANGE
;
475 /* Anti-ranges that can be represented as ranges should be so. */
476 if (t
== VR_ANTI_RANGE
)
478 bool is_min
= vrp_val_is_min (min
);
479 bool is_max
= vrp_val_is_max (max
);
481 if (is_min
&& is_max
)
483 /* We cannot deal with empty ranges, drop to varying. */
484 set_value_range_to_varying (vr
);
488 /* As a special exception preserve non-null ranges. */
489 && !(TYPE_UNSIGNED (TREE_TYPE (min
))
490 && integer_zerop (max
)))
492 tree one
= build_int_cst (TREE_TYPE (max
), 1);
493 min
= int_const_binop (PLUS_EXPR
, max
, one
, 0);
494 max
= vrp_val_max (TREE_TYPE (max
));
499 tree one
= build_int_cst (TREE_TYPE (min
), 1);
500 max
= int_const_binop (MINUS_EXPR
, min
, one
, 0);
501 min
= vrp_val_min (TREE_TYPE (min
));
506 set_value_range (vr
, t
, min
, max
, equiv
);
509 /* Copy value range FROM into value range TO. */
512 copy_value_range (value_range_t
*to
, value_range_t
*from
)
514 set_value_range (to
, from
->type
, from
->min
, from
->max
, from
->equiv
);
517 /* Set value range VR to a single value. This function is only called
518 with values we get from statements, and exists to clear the
519 TREE_OVERFLOW flag so that we don't think we have an overflow
520 infinity when we shouldn't. */
523 set_value_range_to_value (value_range_t
*vr
, tree val
, bitmap equiv
)
525 gcc_assert (is_gimple_min_invariant (val
));
526 val
= avoid_overflow_infinity (val
);
527 set_value_range (vr
, VR_RANGE
, val
, val
, equiv
);
530 /* Set value range VR to a non-negative range of type TYPE.
531 OVERFLOW_INFINITY indicates whether to use an overflow infinity
532 rather than TYPE_MAX_VALUE; this should be true if we determine
533 that the range is nonnegative based on the assumption that signed
534 overflow does not occur. */
537 set_value_range_to_nonnegative (value_range_t
*vr
, tree type
,
538 bool overflow_infinity
)
542 if (overflow_infinity
&& !supports_overflow_infinity (type
))
544 set_value_range_to_varying (vr
);
548 zero
= build_int_cst (type
, 0);
549 set_value_range (vr
, VR_RANGE
, zero
,
551 ? positive_overflow_infinity (type
)
552 : TYPE_MAX_VALUE (type
)),
556 /* Set value range VR to a non-NULL range of type TYPE. */
559 set_value_range_to_nonnull (value_range_t
*vr
, tree type
)
561 tree zero
= build_int_cst (type
, 0);
562 set_value_range (vr
, VR_ANTI_RANGE
, zero
, zero
, vr
->equiv
);
566 /* Set value range VR to a NULL range of type TYPE. */
569 set_value_range_to_null (value_range_t
*vr
, tree type
)
571 set_value_range_to_value (vr
, build_int_cst (type
, 0), vr
->equiv
);
575 /* Set value range VR to a range of a truthvalue of type TYPE. */
578 set_value_range_to_truthvalue (value_range_t
*vr
, tree type
)
580 if (TYPE_PRECISION (type
) == 1)
581 set_value_range_to_varying (vr
);
583 set_value_range (vr
, VR_RANGE
,
584 build_int_cst (type
, 0), build_int_cst (type
, 1),
589 /* Set value range VR to VR_UNDEFINED. */
592 set_value_range_to_undefined (value_range_t
*vr
)
594 vr
->type
= VR_UNDEFINED
;
595 vr
->min
= vr
->max
= NULL_TREE
;
597 bitmap_clear (vr
->equiv
);
601 /* Return value range information for VAR.
603 If we have no values ranges recorded (ie, VRP is not running), then
604 return NULL. Otherwise create an empty range if none existed for VAR. */
606 static value_range_t
*
607 get_value_range (const_tree var
)
611 unsigned ver
= SSA_NAME_VERSION (var
);
613 /* If we have no recorded ranges, then return NULL. */
621 /* Create a default value range. */
622 vr_value
[ver
] = vr
= XCNEW (value_range_t
);
624 /* Defer allocating the equivalence set. */
627 /* If VAR is a default definition, the variable can take any value
629 sym
= SSA_NAME_VAR (var
);
630 if (SSA_NAME_IS_DEFAULT_DEF (var
))
632 /* Try to use the "nonnull" attribute to create ~[0, 0]
633 anti-ranges for pointers. Note that this is only valid with
634 default definitions of PARM_DECLs. */
635 if (TREE_CODE (sym
) == PARM_DECL
636 && POINTER_TYPE_P (TREE_TYPE (sym
))
637 && nonnull_arg_p (sym
))
638 set_value_range_to_nonnull (vr
, TREE_TYPE (sym
));
640 set_value_range_to_varying (vr
);
646 /* Return true, if VAL1 and VAL2 are equal values for VRP purposes. */
649 vrp_operand_equal_p (const_tree val1
, const_tree val2
)
653 if (!val1
|| !val2
|| !operand_equal_p (val1
, val2
, 0))
655 if (is_overflow_infinity (val1
))
656 return is_overflow_infinity (val2
);
660 /* Return true, if the bitmaps B1 and B2 are equal. */
663 vrp_bitmap_equal_p (const_bitmap b1
, const_bitmap b2
)
667 && bitmap_equal_p (b1
, b2
)));
670 /* Update the value range and equivalence set for variable VAR to
671 NEW_VR. Return true if NEW_VR is different from VAR's previous
674 NOTE: This function assumes that NEW_VR is a temporary value range
675 object created for the sole purpose of updating VAR's range. The
676 storage used by the equivalence set from NEW_VR will be freed by
677 this function. Do not call update_value_range when NEW_VR
678 is the range object associated with another SSA name. */
681 update_value_range (const_tree var
, value_range_t
*new_vr
)
683 value_range_t
*old_vr
;
686 /* Update the value range, if necessary. */
687 old_vr
= get_value_range (var
);
688 is_new
= old_vr
->type
!= new_vr
->type
689 || !vrp_operand_equal_p (old_vr
->min
, new_vr
->min
)
690 || !vrp_operand_equal_p (old_vr
->max
, new_vr
->max
)
691 || !vrp_bitmap_equal_p (old_vr
->equiv
, new_vr
->equiv
);
694 set_value_range (old_vr
, new_vr
->type
, new_vr
->min
, new_vr
->max
,
697 BITMAP_FREE (new_vr
->equiv
);
703 /* Add VAR and VAR's equivalence set to EQUIV. This is the central
704 point where equivalence processing can be turned on/off. */
707 add_equivalence (bitmap
*equiv
, const_tree var
)
709 unsigned ver
= SSA_NAME_VERSION (var
);
710 value_range_t
*vr
= vr_value
[ver
];
713 *equiv
= BITMAP_ALLOC (NULL
);
714 bitmap_set_bit (*equiv
, ver
);
716 bitmap_ior_into (*equiv
, vr
->equiv
);
720 /* Return true if VR is ~[0, 0]. */
723 range_is_nonnull (value_range_t
*vr
)
725 return vr
->type
== VR_ANTI_RANGE
726 && integer_zerop (vr
->min
)
727 && integer_zerop (vr
->max
);
731 /* Return true if VR is [0, 0]. */
734 range_is_null (value_range_t
*vr
)
736 return vr
->type
== VR_RANGE
737 && integer_zerop (vr
->min
)
738 && integer_zerop (vr
->max
);
742 /* Return true if value range VR involves at least one symbol. */
745 symbolic_range_p (value_range_t
*vr
)
747 return (!is_gimple_min_invariant (vr
->min
)
748 || !is_gimple_min_invariant (vr
->max
));
751 /* Return true if value range VR uses an overflow infinity. */
754 overflow_infinity_range_p (value_range_t
*vr
)
756 return (vr
->type
== VR_RANGE
757 && (is_overflow_infinity (vr
->min
)
758 || is_overflow_infinity (vr
->max
)));
761 /* Return false if we can not make a valid comparison based on VR;
762 this will be the case if it uses an overflow infinity and overflow
763 is not undefined (i.e., -fno-strict-overflow is in effect).
764 Otherwise return true, and set *STRICT_OVERFLOW_P to true if VR
765 uses an overflow infinity. */
768 usable_range_p (value_range_t
*vr
, bool *strict_overflow_p
)
770 gcc_assert (vr
->type
== VR_RANGE
);
771 if (is_overflow_infinity (vr
->min
))
773 *strict_overflow_p
= true;
774 if (!TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (vr
->min
)))
777 if (is_overflow_infinity (vr
->max
))
779 *strict_overflow_p
= true;
780 if (!TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (vr
->max
)))
787 /* Like tree_expr_nonnegative_warnv_p, but this function uses value
788 ranges obtained so far. */
791 vrp_expr_computes_nonnegative (tree expr
, bool *strict_overflow_p
)
793 return (tree_expr_nonnegative_warnv_p (expr
, strict_overflow_p
)
794 || (TREE_CODE (expr
) == SSA_NAME
795 && ssa_name_nonnegative_p (expr
)));
798 /* Return true if the result of assignment STMT is know to be non-negative.
799 If the return value is based on the assumption that signed overflow is
800 undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't change
801 *STRICT_OVERFLOW_P.*/
804 gimple_assign_nonnegative_warnv_p (gimple stmt
, bool *strict_overflow_p
)
806 enum tree_code code
= gimple_assign_rhs_code (stmt
);
807 switch (get_gimple_rhs_class (code
))
809 case GIMPLE_UNARY_RHS
:
810 return tree_unary_nonnegative_warnv_p (gimple_assign_rhs_code (stmt
),
811 gimple_expr_type (stmt
),
812 gimple_assign_rhs1 (stmt
),
814 case GIMPLE_BINARY_RHS
:
815 return tree_binary_nonnegative_warnv_p (gimple_assign_rhs_code (stmt
),
816 gimple_expr_type (stmt
),
817 gimple_assign_rhs1 (stmt
),
818 gimple_assign_rhs2 (stmt
),
820 case GIMPLE_SINGLE_RHS
:
821 return tree_single_nonnegative_warnv_p (gimple_assign_rhs1 (stmt
),
823 case GIMPLE_INVALID_RHS
:
830 /* Return true if return value of call STMT is know to be non-negative.
831 If the return value is based on the assumption that signed overflow is
832 undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't change
833 *STRICT_OVERFLOW_P.*/
836 gimple_call_nonnegative_warnv_p (gimple stmt
, bool *strict_overflow_p
)
838 tree arg0
= gimple_call_num_args (stmt
) > 0 ?
839 gimple_call_arg (stmt
, 0) : NULL_TREE
;
840 tree arg1
= gimple_call_num_args (stmt
) > 1 ?
841 gimple_call_arg (stmt
, 1) : NULL_TREE
;
843 return tree_call_nonnegative_warnv_p (gimple_expr_type (stmt
),
844 gimple_call_fndecl (stmt
),
850 /* Return true if STMT is know to to compute a non-negative value.
851 If the return value is based on the assumption that signed overflow is
852 undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't change
853 *STRICT_OVERFLOW_P.*/
856 gimple_stmt_nonnegative_warnv_p (gimple stmt
, bool *strict_overflow_p
)
858 switch (gimple_code (stmt
))
861 return gimple_assign_nonnegative_warnv_p (stmt
, strict_overflow_p
);
863 return gimple_call_nonnegative_warnv_p (stmt
, strict_overflow_p
);
869 /* Return true if the result of assignment STMT is know to be non-zero.
870 If the return value is based on the assumption that signed overflow is
871 undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't change
872 *STRICT_OVERFLOW_P.*/
875 gimple_assign_nonzero_warnv_p (gimple stmt
, bool *strict_overflow_p
)
877 enum tree_code code
= gimple_assign_rhs_code (stmt
);
878 switch (get_gimple_rhs_class (code
))
880 case GIMPLE_UNARY_RHS
:
881 return tree_unary_nonzero_warnv_p (gimple_assign_rhs_code (stmt
),
882 gimple_expr_type (stmt
),
883 gimple_assign_rhs1 (stmt
),
885 case GIMPLE_BINARY_RHS
:
886 return tree_binary_nonzero_warnv_p (gimple_assign_rhs_code (stmt
),
887 gimple_expr_type (stmt
),
888 gimple_assign_rhs1 (stmt
),
889 gimple_assign_rhs2 (stmt
),
891 case GIMPLE_SINGLE_RHS
:
892 return tree_single_nonzero_warnv_p (gimple_assign_rhs1 (stmt
),
894 case GIMPLE_INVALID_RHS
:
901 /* Return true if STMT is know to to compute a non-zero value.
902 If the return value is based on the assumption that signed overflow is
903 undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't change
904 *STRICT_OVERFLOW_P.*/
907 gimple_stmt_nonzero_warnv_p (gimple stmt
, bool *strict_overflow_p
)
909 switch (gimple_code (stmt
))
912 return gimple_assign_nonzero_warnv_p (stmt
, strict_overflow_p
);
914 return gimple_alloca_call_p (stmt
);
920 /* Like tree_expr_nonzero_warnv_p, but this function uses value ranges
924 vrp_stmt_computes_nonzero (gimple stmt
, bool *strict_overflow_p
)
926 if (gimple_stmt_nonzero_warnv_p (stmt
, strict_overflow_p
))
929 /* If we have an expression of the form &X->a, then the expression
930 is nonnull if X is nonnull. */
931 if (is_gimple_assign (stmt
)
932 && gimple_assign_rhs_code (stmt
) == ADDR_EXPR
)
934 tree expr
= gimple_assign_rhs1 (stmt
);
935 tree base
= get_base_address (TREE_OPERAND (expr
, 0));
937 if (base
!= NULL_TREE
938 && TREE_CODE (base
) == INDIRECT_REF
939 && TREE_CODE (TREE_OPERAND (base
, 0)) == SSA_NAME
)
941 value_range_t
*vr
= get_value_range (TREE_OPERAND (base
, 0));
942 if (range_is_nonnull (vr
))
950 /* Returns true if EXPR is a valid value (as expected by compare_values) --
951 a gimple invariant, or SSA_NAME +- CST. */
954 valid_value_p (tree expr
)
956 if (TREE_CODE (expr
) == SSA_NAME
)
959 if (TREE_CODE (expr
) == PLUS_EXPR
960 || TREE_CODE (expr
) == MINUS_EXPR
)
961 return (TREE_CODE (TREE_OPERAND (expr
, 0)) == SSA_NAME
962 && TREE_CODE (TREE_OPERAND (expr
, 1)) == INTEGER_CST
);
964 return is_gimple_min_invariant (expr
);
970 -2 if those are incomparable. */
972 operand_less_p (tree val
, tree val2
)
974 /* LT is folded faster than GE and others. Inline the common case. */
975 if (TREE_CODE (val
) == INTEGER_CST
&& TREE_CODE (val2
) == INTEGER_CST
)
977 if (TYPE_UNSIGNED (TREE_TYPE (val
)))
978 return INT_CST_LT_UNSIGNED (val
, val2
);
981 if (INT_CST_LT (val
, val2
))
989 fold_defer_overflow_warnings ();
991 tcmp
= fold_binary_to_constant (LT_EXPR
, boolean_type_node
, val
, val2
);
993 fold_undefer_and_ignore_overflow_warnings ();
996 || TREE_CODE (tcmp
) != INTEGER_CST
)
999 if (!integer_zerop (tcmp
))
1003 /* val >= val2, not considering overflow infinity. */
1004 if (is_negative_overflow_infinity (val
))
1005 return is_negative_overflow_infinity (val2
) ? 0 : 1;
1006 else if (is_positive_overflow_infinity (val2
))
1007 return is_positive_overflow_infinity (val
) ? 0 : 1;
1012 /* Compare two values VAL1 and VAL2. Return
1014 -2 if VAL1 and VAL2 cannot be compared at compile-time,
1017 +1 if VAL1 > VAL2, and
1020 This is similar to tree_int_cst_compare but supports pointer values
1021 and values that cannot be compared at compile time.
1023 If STRICT_OVERFLOW_P is not NULL, then set *STRICT_OVERFLOW_P to
1024 true if the return value is only valid if we assume that signed
1025 overflow is undefined. */
1028 compare_values_warnv (tree val1
, tree val2
, bool *strict_overflow_p
)
1033 /* Below we rely on the fact that VAL1 and VAL2 are both pointers or
1035 gcc_assert (POINTER_TYPE_P (TREE_TYPE (val1
))
1036 == POINTER_TYPE_P (TREE_TYPE (val2
)));
1037 /* Convert the two values into the same type. This is needed because
1038 sizetype causes sign extension even for unsigned types. */
1039 val2
= fold_convert (TREE_TYPE (val1
), val2
);
1040 STRIP_USELESS_TYPE_CONVERSION (val2
);
1042 if ((TREE_CODE (val1
) == SSA_NAME
1043 || TREE_CODE (val1
) == PLUS_EXPR
1044 || TREE_CODE (val1
) == MINUS_EXPR
)
1045 && (TREE_CODE (val2
) == SSA_NAME
1046 || TREE_CODE (val2
) == PLUS_EXPR
1047 || TREE_CODE (val2
) == MINUS_EXPR
))
1049 tree n1
, c1
, n2
, c2
;
1050 enum tree_code code1
, code2
;
1052 /* If VAL1 and VAL2 are of the form 'NAME [+-] CST' or 'NAME',
1053 return -1 or +1 accordingly. If VAL1 and VAL2 don't use the
1054 same name, return -2. */
1055 if (TREE_CODE (val1
) == SSA_NAME
)
1063 code1
= TREE_CODE (val1
);
1064 n1
= TREE_OPERAND (val1
, 0);
1065 c1
= TREE_OPERAND (val1
, 1);
1066 if (tree_int_cst_sgn (c1
) == -1)
1068 if (is_negative_overflow_infinity (c1
))
1070 c1
= fold_unary_to_constant (NEGATE_EXPR
, TREE_TYPE (c1
), c1
);
1073 code1
= code1
== MINUS_EXPR
? PLUS_EXPR
: MINUS_EXPR
;
1077 if (TREE_CODE (val2
) == SSA_NAME
)
1085 code2
= TREE_CODE (val2
);
1086 n2
= TREE_OPERAND (val2
, 0);
1087 c2
= TREE_OPERAND (val2
, 1);
1088 if (tree_int_cst_sgn (c2
) == -1)
1090 if (is_negative_overflow_infinity (c2
))
1092 c2
= fold_unary_to_constant (NEGATE_EXPR
, TREE_TYPE (c2
), c2
);
1095 code2
= code2
== MINUS_EXPR
? PLUS_EXPR
: MINUS_EXPR
;
1099 /* Both values must use the same name. */
1103 if (code1
== SSA_NAME
1104 && code2
== SSA_NAME
)
1108 /* If overflow is defined we cannot simplify more. */
1109 if (!TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (val1
)))
1112 if (strict_overflow_p
!= NULL
1113 && (code1
== SSA_NAME
|| !TREE_NO_WARNING (val1
))
1114 && (code2
== SSA_NAME
|| !TREE_NO_WARNING (val2
)))
1115 *strict_overflow_p
= true;
1117 if (code1
== SSA_NAME
)
1119 if (code2
== PLUS_EXPR
)
1120 /* NAME < NAME + CST */
1122 else if (code2
== MINUS_EXPR
)
1123 /* NAME > NAME - CST */
1126 else if (code1
== PLUS_EXPR
)
1128 if (code2
== SSA_NAME
)
1129 /* NAME + CST > NAME */
1131 else if (code2
== PLUS_EXPR
)
1132 /* NAME + CST1 > NAME + CST2, if CST1 > CST2 */
1133 return compare_values_warnv (c1
, c2
, strict_overflow_p
);
1134 else if (code2
== MINUS_EXPR
)
1135 /* NAME + CST1 > NAME - CST2 */
1138 else if (code1
== MINUS_EXPR
)
1140 if (code2
== SSA_NAME
)
1141 /* NAME - CST < NAME */
1143 else if (code2
== PLUS_EXPR
)
1144 /* NAME - CST1 < NAME + CST2 */
1146 else if (code2
== MINUS_EXPR
)
1147 /* NAME - CST1 > NAME - CST2, if CST1 < CST2. Notice that
1148 C1 and C2 are swapped in the call to compare_values. */
1149 return compare_values_warnv (c2
, c1
, strict_overflow_p
);
1155 /* We cannot compare non-constants. */
1156 if (!is_gimple_min_invariant (val1
) || !is_gimple_min_invariant (val2
))
1159 if (!POINTER_TYPE_P (TREE_TYPE (val1
)))
1161 /* We cannot compare overflowed values, except for overflow
1163 if (TREE_OVERFLOW (val1
) || TREE_OVERFLOW (val2
))
1165 if (strict_overflow_p
!= NULL
)
1166 *strict_overflow_p
= true;
1167 if (is_negative_overflow_infinity (val1
))
1168 return is_negative_overflow_infinity (val2
) ? 0 : -1;
1169 else if (is_negative_overflow_infinity (val2
))
1171 else if (is_positive_overflow_infinity (val1
))
1172 return is_positive_overflow_infinity (val2
) ? 0 : 1;
1173 else if (is_positive_overflow_infinity (val2
))
1178 return tree_int_cst_compare (val1
, val2
);
1184 /* First see if VAL1 and VAL2 are not the same. */
1185 if (val1
== val2
|| operand_equal_p (val1
, val2
, 0))
1188 /* If VAL1 is a lower address than VAL2, return -1. */
1189 if (operand_less_p (val1
, val2
) == 1)
1192 /* If VAL1 is a higher address than VAL2, return +1. */
1193 if (operand_less_p (val2
, val1
) == 1)
1196 /* If VAL1 is different than VAL2, return +2.
1197 For integer constants we either have already returned -1 or 1
1198 or they are equivalent. We still might succeed in proving
1199 something about non-trivial operands. */
1200 if (TREE_CODE (val1
) != INTEGER_CST
1201 || TREE_CODE (val2
) != INTEGER_CST
)
1203 t
= fold_binary_to_constant (NE_EXPR
, boolean_type_node
, val1
, val2
);
1204 if (t
&& integer_onep (t
))
1212 /* Compare values like compare_values_warnv, but treat comparisons of
1213 nonconstants which rely on undefined overflow as incomparable. */
1216 compare_values (tree val1
, tree val2
)
1222 ret
= compare_values_warnv (val1
, val2
, &sop
);
1224 && (!is_gimple_min_invariant (val1
) || !is_gimple_min_invariant (val2
)))
1230 /* Return 1 if VAL is inside value range VR (VR->MIN <= VAL <= VR->MAX),
1231 0 if VAL is not inside VR,
1232 -2 if we cannot tell either way.
1234 FIXME, the current semantics of this functions are a bit quirky
1235 when taken in the context of VRP. In here we do not care
1236 about VR's type. If VR is the anti-range ~[3, 5] the call
1237 value_inside_range (4, VR) will return 1.
1239 This is counter-intuitive in a strict sense, but the callers
1240 currently expect this. They are calling the function
1241 merely to determine whether VR->MIN <= VAL <= VR->MAX. The
1242 callers are applying the VR_RANGE/VR_ANTI_RANGE semantics
1245 This also applies to value_ranges_intersect_p and
1246 range_includes_zero_p. The semantics of VR_RANGE and
1247 VR_ANTI_RANGE should be encoded here, but that also means
1248 adapting the users of these functions to the new semantics.
1250 Benchmark compile/20001226-1.c compilation time after changing this
1254 value_inside_range (tree val
, value_range_t
* vr
)
1258 cmp1
= operand_less_p (val
, vr
->min
);
1264 cmp2
= operand_less_p (vr
->max
, val
);
1272 /* Return true if value ranges VR0 and VR1 have a non-empty
1275 Benchmark compile/20001226-1.c compilation time after changing this
1280 value_ranges_intersect_p (value_range_t
*vr0
, value_range_t
*vr1
)
1282 /* The value ranges do not intersect if the maximum of the first range is
1283 less than the minimum of the second range or vice versa.
1284 When those relations are unknown, we can't do any better. */
1285 if (operand_less_p (vr0
->max
, vr1
->min
) != 0)
1287 if (operand_less_p (vr1
->max
, vr0
->min
) != 0)
1293 /* Return true if VR includes the value zero, false otherwise. FIXME,
1294 currently this will return false for an anti-range like ~[-4, 3].
1295 This will be wrong when the semantics of value_inside_range are
1296 modified (currently the users of this function expect these
1300 range_includes_zero_p (value_range_t
*vr
)
1304 gcc_assert (vr
->type
!= VR_UNDEFINED
1305 && vr
->type
!= VR_VARYING
1306 && !symbolic_range_p (vr
));
1308 zero
= build_int_cst (TREE_TYPE (vr
->min
), 0);
1309 return (value_inside_range (zero
, vr
) == 1);
1312 /* Return true if T, an SSA_NAME, is known to be nonnegative. Return
1313 false otherwise or if no value range information is available. */
1316 ssa_name_nonnegative_p (const_tree t
)
1318 value_range_t
*vr
= get_value_range (t
);
1323 /* Testing for VR_ANTI_RANGE is not useful here as any anti-range
1324 which would return a useful value should be encoded as a VR_RANGE. */
1325 if (vr
->type
== VR_RANGE
)
1327 int result
= compare_values (vr
->min
, integer_zero_node
);
1329 return (result
== 0 || result
== 1);
1334 /* Return true if T, an SSA_NAME, is known to be nonzero. Return
1335 false otherwise or if no value range information is available. */
1338 ssa_name_nonzero_p (const_tree t
)
1340 value_range_t
*vr
= get_value_range (t
);
1345 /* A VR_RANGE which does not include zero is a nonzero value. */
1346 if (vr
->type
== VR_RANGE
&& !symbolic_range_p (vr
))
1347 return ! range_includes_zero_p (vr
);
1349 /* A VR_ANTI_RANGE which does include zero is a nonzero value. */
1350 if (vr
->type
== VR_ANTI_RANGE
&& !symbolic_range_p (vr
))
1351 return range_includes_zero_p (vr
);
1357 /* Extract value range information from an ASSERT_EXPR EXPR and store
1361 extract_range_from_assert (value_range_t
*vr_p
, tree expr
)
1363 tree var
, cond
, limit
, min
, max
, type
;
1364 value_range_t
*var_vr
, *limit_vr
;
1365 enum tree_code cond_code
;
1367 var
= ASSERT_EXPR_VAR (expr
);
1368 cond
= ASSERT_EXPR_COND (expr
);
1370 gcc_assert (COMPARISON_CLASS_P (cond
));
1372 /* Find VAR in the ASSERT_EXPR conditional. */
1373 if (var
== TREE_OPERAND (cond
, 0)
1374 || TREE_CODE (TREE_OPERAND (cond
, 0)) == PLUS_EXPR
1375 || TREE_CODE (TREE_OPERAND (cond
, 0)) == NOP_EXPR
)
1377 /* If the predicate is of the form VAR COMP LIMIT, then we just
1378 take LIMIT from the RHS and use the same comparison code. */
1379 cond_code
= TREE_CODE (cond
);
1380 limit
= TREE_OPERAND (cond
, 1);
1381 cond
= TREE_OPERAND (cond
, 0);
1385 /* If the predicate is of the form LIMIT COMP VAR, then we need
1386 to flip around the comparison code to create the proper range
1388 cond_code
= swap_tree_comparison (TREE_CODE (cond
));
1389 limit
= TREE_OPERAND (cond
, 0);
1390 cond
= TREE_OPERAND (cond
, 1);
1393 limit
= avoid_overflow_infinity (limit
);
1395 type
= TREE_TYPE (limit
);
1396 gcc_assert (limit
!= var
);
1398 /* For pointer arithmetic, we only keep track of pointer equality
1400 if (POINTER_TYPE_P (type
) && cond_code
!= NE_EXPR
&& cond_code
!= EQ_EXPR
)
1402 set_value_range_to_varying (vr_p
);
1406 /* If LIMIT is another SSA name and LIMIT has a range of its own,
1407 try to use LIMIT's range to avoid creating symbolic ranges
1409 limit_vr
= (TREE_CODE (limit
) == SSA_NAME
) ? get_value_range (limit
) : NULL
;
1411 /* LIMIT's range is only interesting if it has any useful information. */
1413 && (limit_vr
->type
== VR_UNDEFINED
1414 || limit_vr
->type
== VR_VARYING
1415 || symbolic_range_p (limit_vr
)))
1418 /* Initially, the new range has the same set of equivalences of
1419 VAR's range. This will be revised before returning the final
1420 value. Since assertions may be chained via mutually exclusive
1421 predicates, we will need to trim the set of equivalences before
1423 gcc_assert (vr_p
->equiv
== NULL
);
1424 add_equivalence (&vr_p
->equiv
, var
);
1426 /* Extract a new range based on the asserted comparison for VAR and
1427 LIMIT's value range. Notice that if LIMIT has an anti-range, we
1428 will only use it for equality comparisons (EQ_EXPR). For any
1429 other kind of assertion, we cannot derive a range from LIMIT's
1430 anti-range that can be used to describe the new range. For
1431 instance, ASSERT_EXPR <x_2, x_2 <= b_4>. If b_4 is ~[2, 10],
1432 then b_4 takes on the ranges [-INF, 1] and [11, +INF]. There is
1433 no single range for x_2 that could describe LE_EXPR, so we might
1434 as well build the range [b_4, +INF] for it.
1435 One special case we handle is extracting a range from a
1436 range test encoded as (unsigned)var + CST <= limit. */
1437 if (TREE_CODE (cond
) == NOP_EXPR
1438 || TREE_CODE (cond
) == PLUS_EXPR
)
1440 if (TREE_CODE (cond
) == PLUS_EXPR
)
1442 min
= fold_build1 (NEGATE_EXPR
, TREE_TYPE (TREE_OPERAND (cond
, 1)),
1443 TREE_OPERAND (cond
, 1));
1444 max
= int_const_binop (PLUS_EXPR
, limit
, min
, 0);
1445 cond
= TREE_OPERAND (cond
, 0);
1449 min
= build_int_cst (TREE_TYPE (var
), 0);
1453 /* Make sure to not set TREE_OVERFLOW on the final type
1454 conversion. We are willingly interpreting large positive
1455 unsigned values as negative singed values here. */
1456 min
= force_fit_type_double (TREE_TYPE (var
), TREE_INT_CST_LOW (min
),
1457 TREE_INT_CST_HIGH (min
), 0, false);
1458 max
= force_fit_type_double (TREE_TYPE (var
), TREE_INT_CST_LOW (max
),
1459 TREE_INT_CST_HIGH (max
), 0, false);
1461 /* We can transform a max, min range to an anti-range or
1462 vice-versa. Use set_and_canonicalize_value_range which does
1464 if (cond_code
== LE_EXPR
)
1465 set_and_canonicalize_value_range (vr_p
, VR_RANGE
,
1466 min
, max
, vr_p
->equiv
);
1467 else if (cond_code
== GT_EXPR
)
1468 set_and_canonicalize_value_range (vr_p
, VR_ANTI_RANGE
,
1469 min
, max
, vr_p
->equiv
);
1473 else if (cond_code
== EQ_EXPR
)
1475 enum value_range_type range_type
;
1479 range_type
= limit_vr
->type
;
1480 min
= limit_vr
->min
;
1481 max
= limit_vr
->max
;
1485 range_type
= VR_RANGE
;
1490 set_value_range (vr_p
, range_type
, min
, max
, vr_p
->equiv
);
1492 /* When asserting the equality VAR == LIMIT and LIMIT is another
1493 SSA name, the new range will also inherit the equivalence set
1495 if (TREE_CODE (limit
) == SSA_NAME
)
1496 add_equivalence (&vr_p
->equiv
, limit
);
1498 else if (cond_code
== NE_EXPR
)
1500 /* As described above, when LIMIT's range is an anti-range and
1501 this assertion is an inequality (NE_EXPR), then we cannot
1502 derive anything from the anti-range. For instance, if
1503 LIMIT's range was ~[0, 0], the assertion 'VAR != LIMIT' does
1504 not imply that VAR's range is [0, 0]. So, in the case of
1505 anti-ranges, we just assert the inequality using LIMIT and
1508 If LIMIT_VR is a range, we can only use it to build a new
1509 anti-range if LIMIT_VR is a single-valued range. For
1510 instance, if LIMIT_VR is [0, 1], the predicate
1511 VAR != [0, 1] does not mean that VAR's range is ~[0, 1].
1512 Rather, it means that for value 0 VAR should be ~[0, 0]
1513 and for value 1, VAR should be ~[1, 1]. We cannot
1514 represent these ranges.
1516 The only situation in which we can build a valid
1517 anti-range is when LIMIT_VR is a single-valued range
1518 (i.e., LIMIT_VR->MIN == LIMIT_VR->MAX). In that case,
1519 build the anti-range ~[LIMIT_VR->MIN, LIMIT_VR->MAX]. */
1521 && limit_vr
->type
== VR_RANGE
1522 && compare_values (limit_vr
->min
, limit_vr
->max
) == 0)
1524 min
= limit_vr
->min
;
1525 max
= limit_vr
->max
;
1529 /* In any other case, we cannot use LIMIT's range to build a
1530 valid anti-range. */
1534 /* If MIN and MAX cover the whole range for their type, then
1535 just use the original LIMIT. */
1536 if (INTEGRAL_TYPE_P (type
)
1537 && vrp_val_is_min (min
)
1538 && vrp_val_is_max (max
))
1541 set_value_range (vr_p
, VR_ANTI_RANGE
, min
, max
, vr_p
->equiv
);
1543 else if (cond_code
== LE_EXPR
|| cond_code
== LT_EXPR
)
1545 min
= TYPE_MIN_VALUE (type
);
1547 if (limit_vr
== NULL
|| limit_vr
->type
== VR_ANTI_RANGE
)
1551 /* If LIMIT_VR is of the form [N1, N2], we need to build the
1552 range [MIN, N2] for LE_EXPR and [MIN, N2 - 1] for
1554 max
= limit_vr
->max
;
1557 /* If the maximum value forces us to be out of bounds, simply punt.
1558 It would be pointless to try and do anything more since this
1559 all should be optimized away above us. */
1560 if ((cond_code
== LT_EXPR
1561 && compare_values (max
, min
) == 0)
1562 || is_overflow_infinity (max
))
1563 set_value_range_to_varying (vr_p
);
1566 /* For LT_EXPR, we create the range [MIN, MAX - 1]. */
1567 if (cond_code
== LT_EXPR
)
1569 tree one
= build_int_cst (type
, 1);
1570 max
= fold_build2 (MINUS_EXPR
, type
, max
, one
);
1572 TREE_NO_WARNING (max
) = 1;
1575 set_value_range (vr_p
, VR_RANGE
, min
, max
, vr_p
->equiv
);
1578 else if (cond_code
== GE_EXPR
|| cond_code
== GT_EXPR
)
1580 max
= TYPE_MAX_VALUE (type
);
1582 if (limit_vr
== NULL
|| limit_vr
->type
== VR_ANTI_RANGE
)
1586 /* If LIMIT_VR is of the form [N1, N2], we need to build the
1587 range [N1, MAX] for GE_EXPR and [N1 + 1, MAX] for
1589 min
= limit_vr
->min
;
1592 /* If the minimum value forces us to be out of bounds, simply punt.
1593 It would be pointless to try and do anything more since this
1594 all should be optimized away above us. */
1595 if ((cond_code
== GT_EXPR
1596 && compare_values (min
, max
) == 0)
1597 || is_overflow_infinity (min
))
1598 set_value_range_to_varying (vr_p
);
1601 /* For GT_EXPR, we create the range [MIN + 1, MAX]. */
1602 if (cond_code
== GT_EXPR
)
1604 tree one
= build_int_cst (type
, 1);
1605 min
= fold_build2 (PLUS_EXPR
, type
, min
, one
);
1607 TREE_NO_WARNING (min
) = 1;
1610 set_value_range (vr_p
, VR_RANGE
, min
, max
, vr_p
->equiv
);
1616 /* If VAR already had a known range, it may happen that the new
1617 range we have computed and VAR's range are not compatible. For
1621 p_6 = ASSERT_EXPR <p_5, p_5 == NULL>;
1623 p_8 = ASSERT_EXPR <p_6, p_6 != NULL>;
1625 While the above comes from a faulty program, it will cause an ICE
1626 later because p_8 and p_6 will have incompatible ranges and at
1627 the same time will be considered equivalent. A similar situation
1631 i_6 = ASSERT_EXPR <i_5, i_5 > 10>;
1633 i_7 = ASSERT_EXPR <i_6, i_6 < 5>;
1635 Again i_6 and i_7 will have incompatible ranges. It would be
1636 pointless to try and do anything with i_7's range because
1637 anything dominated by 'if (i_5 < 5)' will be optimized away.
1638 Note, due to the wa in which simulation proceeds, the statement
1639 i_7 = ASSERT_EXPR <...> we would never be visited because the
1640 conditional 'if (i_5 < 5)' always evaluates to false. However,
1641 this extra check does not hurt and may protect against future
1642 changes to VRP that may get into a situation similar to the
1643 NULL pointer dereference example.
1645 Note that these compatibility tests are only needed when dealing
1646 with ranges or a mix of range and anti-range. If VAR_VR and VR_P
1647 are both anti-ranges, they will always be compatible, because two
1648 anti-ranges will always have a non-empty intersection. */
1650 var_vr
= get_value_range (var
);
1652 /* We may need to make adjustments when VR_P and VAR_VR are numeric
1653 ranges or anti-ranges. */
1654 if (vr_p
->type
== VR_VARYING
1655 || vr_p
->type
== VR_UNDEFINED
1656 || var_vr
->type
== VR_VARYING
1657 || var_vr
->type
== VR_UNDEFINED
1658 || symbolic_range_p (vr_p
)
1659 || symbolic_range_p (var_vr
))
1662 if (var_vr
->type
== VR_RANGE
&& vr_p
->type
== VR_RANGE
)
1664 /* If the two ranges have a non-empty intersection, we can
1665 refine the resulting range. Since the assert expression
1666 creates an equivalency and at the same time it asserts a
1667 predicate, we can take the intersection of the two ranges to
1668 get better precision. */
1669 if (value_ranges_intersect_p (var_vr
, vr_p
))
1671 /* Use the larger of the two minimums. */
1672 if (compare_values (vr_p
->min
, var_vr
->min
) == -1)
1677 /* Use the smaller of the two maximums. */
1678 if (compare_values (vr_p
->max
, var_vr
->max
) == 1)
1683 set_value_range (vr_p
, vr_p
->type
, min
, max
, vr_p
->equiv
);
1687 /* The two ranges do not intersect, set the new range to
1688 VARYING, because we will not be able to do anything
1689 meaningful with it. */
1690 set_value_range_to_varying (vr_p
);
1693 else if ((var_vr
->type
== VR_RANGE
&& vr_p
->type
== VR_ANTI_RANGE
)
1694 || (var_vr
->type
== VR_ANTI_RANGE
&& vr_p
->type
== VR_RANGE
))
1696 /* A range and an anti-range will cancel each other only if
1697 their ends are the same. For instance, in the example above,
1698 p_8's range ~[0, 0] and p_6's range [0, 0] are incompatible,
1699 so VR_P should be set to VR_VARYING. */
1700 if (compare_values (var_vr
->min
, vr_p
->min
) == 0
1701 && compare_values (var_vr
->max
, vr_p
->max
) == 0)
1702 set_value_range_to_varying (vr_p
);
1705 tree min
, max
, anti_min
, anti_max
, real_min
, real_max
;
1708 /* We want to compute the logical AND of the two ranges;
1709 there are three cases to consider.
1712 1. The VR_ANTI_RANGE range is completely within the
1713 VR_RANGE and the endpoints of the ranges are
1714 different. In that case the resulting range
1715 should be whichever range is more precise.
1716 Typically that will be the VR_RANGE.
1718 2. The VR_ANTI_RANGE is completely disjoint from
1719 the VR_RANGE. In this case the resulting range
1720 should be the VR_RANGE.
1722 3. There is some overlap between the VR_ANTI_RANGE
1725 3a. If the high limit of the VR_ANTI_RANGE resides
1726 within the VR_RANGE, then the result is a new
1727 VR_RANGE starting at the high limit of the
1728 VR_ANTI_RANGE + 1 and extending to the
1729 high limit of the original VR_RANGE.
1731 3b. If the low limit of the VR_ANTI_RANGE resides
1732 within the VR_RANGE, then the result is a new
1733 VR_RANGE starting at the low limit of the original
1734 VR_RANGE and extending to the low limit of the
1735 VR_ANTI_RANGE - 1. */
1736 if (vr_p
->type
== VR_ANTI_RANGE
)
1738 anti_min
= vr_p
->min
;
1739 anti_max
= vr_p
->max
;
1740 real_min
= var_vr
->min
;
1741 real_max
= var_vr
->max
;
1745 anti_min
= var_vr
->min
;
1746 anti_max
= var_vr
->max
;
1747 real_min
= vr_p
->min
;
1748 real_max
= vr_p
->max
;
1752 /* Case 1, VR_ANTI_RANGE completely within VR_RANGE,
1753 not including any endpoints. */
1754 if (compare_values (anti_max
, real_max
) == -1
1755 && compare_values (anti_min
, real_min
) == 1)
1757 /* If the range is covering the whole valid range of
1758 the type keep the anti-range. */
1759 if (!vrp_val_is_min (real_min
)
1760 || !vrp_val_is_max (real_max
))
1761 set_value_range (vr_p
, VR_RANGE
, real_min
,
1762 real_max
, vr_p
->equiv
);
1764 /* Case 2, VR_ANTI_RANGE completely disjoint from
1766 else if (compare_values (anti_min
, real_max
) == 1
1767 || compare_values (anti_max
, real_min
) == -1)
1769 set_value_range (vr_p
, VR_RANGE
, real_min
,
1770 real_max
, vr_p
->equiv
);
1772 /* Case 3a, the anti-range extends into the low
1773 part of the real range. Thus creating a new
1774 low for the real range. */
1775 else if (((cmp
= compare_values (anti_max
, real_min
)) == 1
1777 && compare_values (anti_max
, real_max
) == -1)
1779 gcc_assert (!is_positive_overflow_infinity (anti_max
));
1780 if (needs_overflow_infinity (TREE_TYPE (anti_max
))
1781 && vrp_val_is_max (anti_max
))
1783 if (!supports_overflow_infinity (TREE_TYPE (var_vr
->min
)))
1785 set_value_range_to_varying (vr_p
);
1788 min
= positive_overflow_infinity (TREE_TYPE (var_vr
->min
));
1790 else if (!POINTER_TYPE_P (TREE_TYPE (var_vr
->min
)))
1791 min
= fold_build2 (PLUS_EXPR
, TREE_TYPE (var_vr
->min
),
1793 build_int_cst (TREE_TYPE (var_vr
->min
), 1));
1795 min
= fold_build2 (POINTER_PLUS_EXPR
, TREE_TYPE (var_vr
->min
),
1796 anti_max
, size_int (1));
1798 set_value_range (vr_p
, VR_RANGE
, min
, max
, vr_p
->equiv
);
1800 /* Case 3b, the anti-range extends into the high
1801 part of the real range. Thus creating a new
1802 higher for the real range. */
1803 else if (compare_values (anti_min
, real_min
) == 1
1804 && ((cmp
= compare_values (anti_min
, real_max
)) == -1
1807 gcc_assert (!is_negative_overflow_infinity (anti_min
));
1808 if (needs_overflow_infinity (TREE_TYPE (anti_min
))
1809 && vrp_val_is_min (anti_min
))
1811 if (!supports_overflow_infinity (TREE_TYPE (var_vr
->min
)))
1813 set_value_range_to_varying (vr_p
);
1816 max
= negative_overflow_infinity (TREE_TYPE (var_vr
->min
));
1818 else if (!POINTER_TYPE_P (TREE_TYPE (var_vr
->min
)))
1819 max
= fold_build2 (MINUS_EXPR
, TREE_TYPE (var_vr
->min
),
1821 build_int_cst (TREE_TYPE (var_vr
->min
), 1));
1823 max
= fold_build2 (POINTER_PLUS_EXPR
, TREE_TYPE (var_vr
->min
),
1827 set_value_range (vr_p
, VR_RANGE
, min
, max
, vr_p
->equiv
);
1834 /* Extract range information from SSA name VAR and store it in VR. If
1835 VAR has an interesting range, use it. Otherwise, create the
1836 range [VAR, VAR] and return it. This is useful in situations where
1837 we may have conditionals testing values of VARYING names. For
1844 Even if y_5 is deemed VARYING, we can determine that x_3 > y_5 is
1848 extract_range_from_ssa_name (value_range_t
*vr
, tree var
)
1850 value_range_t
*var_vr
= get_value_range (var
);
1852 if (var_vr
->type
!= VR_UNDEFINED
&& var_vr
->type
!= VR_VARYING
)
1853 copy_value_range (vr
, var_vr
);
1855 set_value_range (vr
, VR_RANGE
, var
, var
, NULL
);
1857 add_equivalence (&vr
->equiv
, var
);
1861 /* Wrapper around int_const_binop. If the operation overflows and we
1862 are not using wrapping arithmetic, then adjust the result to be
1863 -INF or +INF depending on CODE, VAL1 and VAL2. This can return
1864 NULL_TREE if we need to use an overflow infinity representation but
1865 the type does not support it. */
1868 vrp_int_const_binop (enum tree_code code
, tree val1
, tree val2
)
1872 res
= int_const_binop (code
, val1
, val2
, 0);
1874 /* If we are not using wrapping arithmetic, operate symbolically
1875 on -INF and +INF. */
1876 if (TYPE_OVERFLOW_WRAPS (TREE_TYPE (val1
)))
1878 int checkz
= compare_values (res
, val1
);
1879 bool overflow
= false;
1881 /* Ensure that res = val1 [+*] val2 >= val1
1882 or that res = val1 - val2 <= val1. */
1883 if ((code
== PLUS_EXPR
1884 && !(checkz
== 1 || checkz
== 0))
1885 || (code
== MINUS_EXPR
1886 && !(checkz
== 0 || checkz
== -1)))
1890 /* Checking for multiplication overflow is done by dividing the
1891 output of the multiplication by the first input of the
1892 multiplication. If the result of that division operation is
1893 not equal to the second input of the multiplication, then the
1894 multiplication overflowed. */
1895 else if (code
== MULT_EXPR
&& !integer_zerop (val1
))
1897 tree tmp
= int_const_binop (TRUNC_DIV_EXPR
,
1900 int check
= compare_values (tmp
, val2
);
1908 res
= copy_node (res
);
1909 TREE_OVERFLOW (res
) = 1;
1913 else if ((TREE_OVERFLOW (res
)
1914 && !TREE_OVERFLOW (val1
)
1915 && !TREE_OVERFLOW (val2
))
1916 || is_overflow_infinity (val1
)
1917 || is_overflow_infinity (val2
))
1919 /* If the operation overflowed but neither VAL1 nor VAL2 are
1920 overflown, return -INF or +INF depending on the operation
1921 and the combination of signs of the operands. */
1922 int sgn1
= tree_int_cst_sgn (val1
);
1923 int sgn2
= tree_int_cst_sgn (val2
);
1925 if (needs_overflow_infinity (TREE_TYPE (res
))
1926 && !supports_overflow_infinity (TREE_TYPE (res
)))
1929 /* We have to punt on adding infinities of different signs,
1930 since we can't tell what the sign of the result should be.
1931 Likewise for subtracting infinities of the same sign. */
1932 if (((code
== PLUS_EXPR
&& sgn1
!= sgn2
)
1933 || (code
== MINUS_EXPR
&& sgn1
== sgn2
))
1934 && is_overflow_infinity (val1
)
1935 && is_overflow_infinity (val2
))
1938 /* Don't try to handle division or shifting of infinities. */
1939 if ((code
== TRUNC_DIV_EXPR
1940 || code
== FLOOR_DIV_EXPR
1941 || code
== CEIL_DIV_EXPR
1942 || code
== EXACT_DIV_EXPR
1943 || code
== ROUND_DIV_EXPR
1944 || code
== RSHIFT_EXPR
)
1945 && (is_overflow_infinity (val1
)
1946 || is_overflow_infinity (val2
)))
1949 /* Notice that we only need to handle the restricted set of
1950 operations handled by extract_range_from_binary_expr.
1951 Among them, only multiplication, addition and subtraction
1952 can yield overflow without overflown operands because we
1953 are working with integral types only... except in the
1954 case VAL1 = -INF and VAL2 = -1 which overflows to +INF
1955 for division too. */
1957 /* For multiplication, the sign of the overflow is given
1958 by the comparison of the signs of the operands. */
1959 if ((code
== MULT_EXPR
&& sgn1
== sgn2
)
1960 /* For addition, the operands must be of the same sign
1961 to yield an overflow. Its sign is therefore that
1962 of one of the operands, for example the first. For
1963 infinite operands X + -INF is negative, not positive. */
1964 || (code
== PLUS_EXPR
1966 ? !is_negative_overflow_infinity (val2
)
1967 : is_positive_overflow_infinity (val2
)))
1968 /* For subtraction, non-infinite operands must be of
1969 different signs to yield an overflow. Its sign is
1970 therefore that of the first operand or the opposite of
1971 that of the second operand. A first operand of 0 counts
1972 as positive here, for the corner case 0 - (-INF), which
1973 overflows, but must yield +INF. For infinite operands 0
1974 - INF is negative, not positive. */
1975 || (code
== MINUS_EXPR
1977 ? !is_positive_overflow_infinity (val2
)
1978 : is_negative_overflow_infinity (val2
)))
1979 /* We only get in here with positive shift count, so the
1980 overflow direction is the same as the sign of val1.
1981 Actually rshift does not overflow at all, but we only
1982 handle the case of shifting overflowed -INF and +INF. */
1983 || (code
== RSHIFT_EXPR
1985 /* For division, the only case is -INF / -1 = +INF. */
1986 || code
== TRUNC_DIV_EXPR
1987 || code
== FLOOR_DIV_EXPR
1988 || code
== CEIL_DIV_EXPR
1989 || code
== EXACT_DIV_EXPR
1990 || code
== ROUND_DIV_EXPR
)
1991 return (needs_overflow_infinity (TREE_TYPE (res
))
1992 ? positive_overflow_infinity (TREE_TYPE (res
))
1993 : TYPE_MAX_VALUE (TREE_TYPE (res
)));
1995 return (needs_overflow_infinity (TREE_TYPE (res
))
1996 ? negative_overflow_infinity (TREE_TYPE (res
))
1997 : TYPE_MIN_VALUE (TREE_TYPE (res
)));
2004 /* Extract range information from a binary expression EXPR based on
2005 the ranges of each of its operands and the expression code. */
2008 extract_range_from_binary_expr (value_range_t
*vr
,
2009 enum tree_code code
,
2010 tree expr_type
, tree op0
, tree op1
)
2012 enum value_range_type type
;
2015 value_range_t vr0
= { VR_UNDEFINED
, NULL_TREE
, NULL_TREE
, NULL
};
2016 value_range_t vr1
= { VR_UNDEFINED
, NULL_TREE
, NULL_TREE
, NULL
};
2018 /* Not all binary expressions can be applied to ranges in a
2019 meaningful way. Handle only arithmetic operations. */
2020 if (code
!= PLUS_EXPR
2021 && code
!= MINUS_EXPR
2022 && code
!= POINTER_PLUS_EXPR
2023 && code
!= MULT_EXPR
2024 && code
!= TRUNC_DIV_EXPR
2025 && code
!= FLOOR_DIV_EXPR
2026 && code
!= CEIL_DIV_EXPR
2027 && code
!= EXACT_DIV_EXPR
2028 && code
!= ROUND_DIV_EXPR
2029 && code
!= RSHIFT_EXPR
2032 && code
!= BIT_AND_EXPR
2033 && code
!= TRUTH_AND_EXPR
2034 && code
!= TRUTH_OR_EXPR
)
2036 set_value_range_to_varying (vr
);
2040 /* Get value ranges for each operand. For constant operands, create
2041 a new value range with the operand to simplify processing. */
2042 if (TREE_CODE (op0
) == SSA_NAME
)
2043 vr0
= *(get_value_range (op0
));
2044 else if (is_gimple_min_invariant (op0
))
2045 set_value_range_to_value (&vr0
, op0
, NULL
);
2047 set_value_range_to_varying (&vr0
);
2049 if (TREE_CODE (op1
) == SSA_NAME
)
2050 vr1
= *(get_value_range (op1
));
2051 else if (is_gimple_min_invariant (op1
))
2052 set_value_range_to_value (&vr1
, op1
, NULL
);
2054 set_value_range_to_varying (&vr1
);
2056 /* If either range is UNDEFINED, so is the result. */
2057 if (vr0
.type
== VR_UNDEFINED
|| vr1
.type
== VR_UNDEFINED
)
2059 set_value_range_to_undefined (vr
);
2063 /* The type of the resulting value range defaults to VR0.TYPE. */
2066 /* Refuse to operate on VARYING ranges, ranges of different kinds
2067 and symbolic ranges. As an exception, we allow BIT_AND_EXPR
2068 because we may be able to derive a useful range even if one of
2069 the operands is VR_VARYING or symbolic range. TODO, we may be
2070 able to derive anti-ranges in some cases. */
2071 if (code
!= BIT_AND_EXPR
2072 && code
!= TRUTH_AND_EXPR
2073 && code
!= TRUTH_OR_EXPR
2074 && (vr0
.type
== VR_VARYING
2075 || vr1
.type
== VR_VARYING
2076 || vr0
.type
!= vr1
.type
2077 || symbolic_range_p (&vr0
)
2078 || symbolic_range_p (&vr1
)))
2080 set_value_range_to_varying (vr
);
2084 /* Now evaluate the expression to determine the new range. */
2085 if (POINTER_TYPE_P (expr_type
)
2086 || POINTER_TYPE_P (TREE_TYPE (op0
))
2087 || POINTER_TYPE_P (TREE_TYPE (op1
)))
2089 if (code
== MIN_EXPR
|| code
== MAX_EXPR
)
2091 /* For MIN/MAX expressions with pointers, we only care about
2092 nullness, if both are non null, then the result is nonnull.
2093 If both are null, then the result is null. Otherwise they
2095 if (range_is_nonnull (&vr0
) && range_is_nonnull (&vr1
))
2096 set_value_range_to_nonnull (vr
, expr_type
);
2097 else if (range_is_null (&vr0
) && range_is_null (&vr1
))
2098 set_value_range_to_null (vr
, expr_type
);
2100 set_value_range_to_varying (vr
);
2104 gcc_assert (code
== POINTER_PLUS_EXPR
);
2105 /* For pointer types, we are really only interested in asserting
2106 whether the expression evaluates to non-NULL. */
2107 if (range_is_nonnull (&vr0
) || range_is_nonnull (&vr1
))
2108 set_value_range_to_nonnull (vr
, expr_type
);
2109 else if (range_is_null (&vr0
) && range_is_null (&vr1
))
2110 set_value_range_to_null (vr
, expr_type
);
2112 set_value_range_to_varying (vr
);
2117 /* For integer ranges, apply the operation to each end of the
2118 range and see what we end up with. */
2119 if (code
== TRUTH_AND_EXPR
2120 || code
== TRUTH_OR_EXPR
)
2122 /* If one of the operands is zero, we know that the whole
2123 expression evaluates zero. */
2124 if (code
== TRUTH_AND_EXPR
2125 && ((vr0
.type
== VR_RANGE
2126 && integer_zerop (vr0
.min
)
2127 && integer_zerop (vr0
.max
))
2128 || (vr1
.type
== VR_RANGE
2129 && integer_zerop (vr1
.min
)
2130 && integer_zerop (vr1
.max
))))
2133 min
= max
= build_int_cst (expr_type
, 0);
2135 /* If one of the operands is one, we know that the whole
2136 expression evaluates one. */
2137 else if (code
== TRUTH_OR_EXPR
2138 && ((vr0
.type
== VR_RANGE
2139 && integer_onep (vr0
.min
)
2140 && integer_onep (vr0
.max
))
2141 || (vr1
.type
== VR_RANGE
2142 && integer_onep (vr1
.min
)
2143 && integer_onep (vr1
.max
))))
2146 min
= max
= build_int_cst (expr_type
, 1);
2148 else if (vr0
.type
!= VR_VARYING
2149 && vr1
.type
!= VR_VARYING
2150 && vr0
.type
== vr1
.type
2151 && !symbolic_range_p (&vr0
)
2152 && !overflow_infinity_range_p (&vr0
)
2153 && !symbolic_range_p (&vr1
)
2154 && !overflow_infinity_range_p (&vr1
))
2156 /* Boolean expressions cannot be folded with int_const_binop. */
2157 min
= fold_binary (code
, expr_type
, vr0
.min
, vr1
.min
);
2158 max
= fold_binary (code
, expr_type
, vr0
.max
, vr1
.max
);
2162 /* The result of a TRUTH_*_EXPR is always true or false. */
2163 set_value_range_to_truthvalue (vr
, expr_type
);
2167 else if (code
== PLUS_EXPR
2169 || code
== MAX_EXPR
)
2171 /* If we have a PLUS_EXPR with two VR_ANTI_RANGEs, drop to
2172 VR_VARYING. It would take more effort to compute a precise
2173 range for such a case. For example, if we have op0 == 1 and
2174 op1 == -1 with their ranges both being ~[0,0], we would have
2175 op0 + op1 == 0, so we cannot claim that the sum is in ~[0,0].
2176 Note that we are guaranteed to have vr0.type == vr1.type at
2178 if (code
== PLUS_EXPR
&& vr0
.type
== VR_ANTI_RANGE
)
2180 set_value_range_to_varying (vr
);
2184 /* For operations that make the resulting range directly
2185 proportional to the original ranges, apply the operation to
2186 the same end of each range. */
2187 min
= vrp_int_const_binop (code
, vr0
.min
, vr1
.min
);
2188 max
= vrp_int_const_binop (code
, vr0
.max
, vr1
.max
);
2190 else if (code
== MULT_EXPR
2191 || code
== TRUNC_DIV_EXPR
2192 || code
== FLOOR_DIV_EXPR
2193 || code
== CEIL_DIV_EXPR
2194 || code
== EXACT_DIV_EXPR
2195 || code
== ROUND_DIV_EXPR
2196 || code
== RSHIFT_EXPR
)
2202 /* If we have an unsigned MULT_EXPR with two VR_ANTI_RANGEs,
2203 drop to VR_VARYING. It would take more effort to compute a
2204 precise range for such a case. For example, if we have
2205 op0 == 65536 and op1 == 65536 with their ranges both being
2206 ~[0,0] on a 32-bit machine, we would have op0 * op1 == 0, so
2207 we cannot claim that the product is in ~[0,0]. Note that we
2208 are guaranteed to have vr0.type == vr1.type at this
2210 if (code
== MULT_EXPR
2211 && vr0
.type
== VR_ANTI_RANGE
2212 && !TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (op0
)))
2214 set_value_range_to_varying (vr
);
2218 /* If we have a RSHIFT_EXPR with any shift values outside [0..prec-1],
2219 then drop to VR_VARYING. Outside of this range we get undefined
2220 behavior from the shift operation. We cannot even trust
2221 SHIFT_COUNT_TRUNCATED at this stage, because that applies to rtl
2222 shifts, and the operation at the tree level may be widened. */
2223 if (code
== RSHIFT_EXPR
)
2225 if (vr1
.type
== VR_ANTI_RANGE
2226 || !vrp_expr_computes_nonnegative (op1
, &sop
)
2228 (build_int_cst (TREE_TYPE (vr1
.max
),
2229 TYPE_PRECISION (expr_type
) - 1),
2232 set_value_range_to_varying (vr
);
2237 /* Multiplications and divisions are a bit tricky to handle,
2238 depending on the mix of signs we have in the two ranges, we
2239 need to operate on different values to get the minimum and
2240 maximum values for the new range. One approach is to figure
2241 out all the variations of range combinations and do the
2244 However, this involves several calls to compare_values and it
2245 is pretty convoluted. It's simpler to do the 4 operations
2246 (MIN0 OP MIN1, MIN0 OP MAX1, MAX0 OP MIN1 and MAX0 OP MAX0 OP
2247 MAX1) and then figure the smallest and largest values to form
2250 /* Divisions by zero result in a VARYING value. */
2251 else if (code
!= MULT_EXPR
2252 && (vr0
.type
== VR_ANTI_RANGE
|| range_includes_zero_p (&vr1
)))
2254 set_value_range_to_varying (vr
);
2258 /* Compute the 4 cross operations. */
2260 val
[0] = vrp_int_const_binop (code
, vr0
.min
, vr1
.min
);
2261 if (val
[0] == NULL_TREE
)
2264 if (vr1
.max
== vr1
.min
)
2268 val
[1] = vrp_int_const_binop (code
, vr0
.min
, vr1
.max
);
2269 if (val
[1] == NULL_TREE
)
2273 if (vr0
.max
== vr0
.min
)
2277 val
[2] = vrp_int_const_binop (code
, vr0
.max
, vr1
.min
);
2278 if (val
[2] == NULL_TREE
)
2282 if (vr0
.min
== vr0
.max
|| vr1
.min
== vr1
.max
)
2286 val
[3] = vrp_int_const_binop (code
, vr0
.max
, vr1
.max
);
2287 if (val
[3] == NULL_TREE
)
2293 set_value_range_to_varying (vr
);
2297 /* Set MIN to the minimum of VAL[i] and MAX to the maximum
2301 for (i
= 1; i
< 4; i
++)
2303 if (!is_gimple_min_invariant (min
)
2304 || (TREE_OVERFLOW (min
) && !is_overflow_infinity (min
))
2305 || !is_gimple_min_invariant (max
)
2306 || (TREE_OVERFLOW (max
) && !is_overflow_infinity (max
)))
2311 if (!is_gimple_min_invariant (val
[i
])
2312 || (TREE_OVERFLOW (val
[i
])
2313 && !is_overflow_infinity (val
[i
])))
2315 /* If we found an overflowed value, set MIN and MAX
2316 to it so that we set the resulting range to
2322 if (compare_values (val
[i
], min
) == -1)
2325 if (compare_values (val
[i
], max
) == 1)
2330 else if (code
== MINUS_EXPR
)
2332 /* If we have a MINUS_EXPR with two VR_ANTI_RANGEs, drop to
2333 VR_VARYING. It would take more effort to compute a precise
2334 range for such a case. For example, if we have op0 == 1 and
2335 op1 == 1 with their ranges both being ~[0,0], we would have
2336 op0 - op1 == 0, so we cannot claim that the difference is in
2337 ~[0,0]. Note that we are guaranteed to have
2338 vr0.type == vr1.type at this point. */
2339 if (vr0
.type
== VR_ANTI_RANGE
)
2341 set_value_range_to_varying (vr
);
2345 /* For MINUS_EXPR, apply the operation to the opposite ends of
2347 min
= vrp_int_const_binop (code
, vr0
.min
, vr1
.max
);
2348 max
= vrp_int_const_binop (code
, vr0
.max
, vr1
.min
);
2350 else if (code
== BIT_AND_EXPR
)
2352 if (vr0
.type
== VR_RANGE
2353 && vr0
.min
== vr0
.max
2354 && TREE_CODE (vr0
.max
) == INTEGER_CST
2355 && !TREE_OVERFLOW (vr0
.max
)
2356 && tree_int_cst_sgn (vr0
.max
) >= 0)
2358 min
= build_int_cst (expr_type
, 0);
2361 else if (vr1
.type
== VR_RANGE
2362 && vr1
.min
== vr1
.max
2363 && TREE_CODE (vr1
.max
) == INTEGER_CST
2364 && !TREE_OVERFLOW (vr1
.max
)
2365 && tree_int_cst_sgn (vr1
.max
) >= 0)
2368 min
= build_int_cst (expr_type
, 0);
2373 set_value_range_to_varying (vr
);
2380 /* If either MIN or MAX overflowed, then set the resulting range to
2381 VARYING. But we do accept an overflow infinity
2383 if (min
== NULL_TREE
2384 || !is_gimple_min_invariant (min
)
2385 || (TREE_OVERFLOW (min
) && !is_overflow_infinity (min
))
2387 || !is_gimple_min_invariant (max
)
2388 || (TREE_OVERFLOW (max
) && !is_overflow_infinity (max
)))
2390 set_value_range_to_varying (vr
);
2396 2) [-INF, +-INF(OVF)]
2397 3) [+-INF(OVF), +INF]
2398 4) [+-INF(OVF), +-INF(OVF)]
2399 We learn nothing when we have INF and INF(OVF) on both sides.
2400 Note that we do accept [-INF, -INF] and [+INF, +INF] without
2402 if ((vrp_val_is_min (min
) || is_overflow_infinity (min
))
2403 && (vrp_val_is_max (max
) || is_overflow_infinity (max
)))
2405 set_value_range_to_varying (vr
);
2409 cmp
= compare_values (min
, max
);
2410 if (cmp
== -2 || cmp
== 1)
2412 /* If the new range has its limits swapped around (MIN > MAX),
2413 then the operation caused one of them to wrap around, mark
2414 the new range VARYING. */
2415 set_value_range_to_varying (vr
);
2418 set_value_range (vr
, type
, min
, max
, NULL
);
2422 /* Extract range information from a unary expression EXPR based on
2423 the range of its operand and the expression code. */
2426 extract_range_from_unary_expr (value_range_t
*vr
, enum tree_code code
,
2427 tree type
, tree op0
)
2431 value_range_t vr0
= { VR_UNDEFINED
, NULL_TREE
, NULL_TREE
, NULL
};
2433 /* Refuse to operate on certain unary expressions for which we
2434 cannot easily determine a resulting range. */
2435 if (code
== FIX_TRUNC_EXPR
2436 || code
== FLOAT_EXPR
2437 || code
== BIT_NOT_EXPR
2438 || code
== CONJ_EXPR
)
2440 set_value_range_to_varying (vr
);
2444 /* Get value ranges for the operand. For constant operands, create
2445 a new value range with the operand to simplify processing. */
2446 if (TREE_CODE (op0
) == SSA_NAME
)
2447 vr0
= *(get_value_range (op0
));
2448 else if (is_gimple_min_invariant (op0
))
2449 set_value_range_to_value (&vr0
, op0
, NULL
);
2451 set_value_range_to_varying (&vr0
);
2453 /* If VR0 is UNDEFINED, so is the result. */
2454 if (vr0
.type
== VR_UNDEFINED
)
2456 set_value_range_to_undefined (vr
);
2460 /* Refuse to operate on symbolic ranges, or if neither operand is
2461 a pointer or integral type. */
2462 if ((!INTEGRAL_TYPE_P (TREE_TYPE (op0
))
2463 && !POINTER_TYPE_P (TREE_TYPE (op0
)))
2464 || (vr0
.type
!= VR_VARYING
2465 && symbolic_range_p (&vr0
)))
2467 set_value_range_to_varying (vr
);
2471 /* If the expression involves pointers, we are only interested in
2472 determining if it evaluates to NULL [0, 0] or non-NULL (~[0, 0]). */
2473 if (POINTER_TYPE_P (type
) || POINTER_TYPE_P (TREE_TYPE (op0
)))
2478 if (range_is_nonnull (&vr0
)
2479 || (tree_unary_nonzero_warnv_p (code
, type
, op0
, &sop
)
2481 set_value_range_to_nonnull (vr
, type
);
2482 else if (range_is_null (&vr0
))
2483 set_value_range_to_null (vr
, type
);
2485 set_value_range_to_varying (vr
);
2490 /* Handle unary expressions on integer ranges. */
2491 if (CONVERT_EXPR_CODE_P (code
)
2492 && INTEGRAL_TYPE_P (type
)
2493 && INTEGRAL_TYPE_P (TREE_TYPE (op0
)))
2495 tree inner_type
= TREE_TYPE (op0
);
2496 tree outer_type
= type
;
2498 /* Always use base-types here. This is important for the
2499 correct signedness. */
2500 if (TREE_TYPE (inner_type
))
2501 inner_type
= TREE_TYPE (inner_type
);
2502 if (TREE_TYPE (outer_type
))
2503 outer_type
= TREE_TYPE (outer_type
);
2505 /* If VR0 is varying and we increase the type precision, assume
2506 a full range for the following transformation. */
2507 if (vr0
.type
== VR_VARYING
2508 && TYPE_PRECISION (inner_type
) < TYPE_PRECISION (outer_type
))
2510 vr0
.type
= VR_RANGE
;
2511 vr0
.min
= TYPE_MIN_VALUE (inner_type
);
2512 vr0
.max
= TYPE_MAX_VALUE (inner_type
);
2515 /* If VR0 is a constant range or anti-range and the conversion is
2516 not truncating we can convert the min and max values and
2517 canonicalize the resulting range. Otherwise we can do the
2518 conversion if the size of the range is less than what the
2519 precision of the target type can represent and the range is
2520 not an anti-range. */
2521 if ((vr0
.type
== VR_RANGE
2522 || vr0
.type
== VR_ANTI_RANGE
)
2523 && TREE_CODE (vr0
.min
) == INTEGER_CST
2524 && TREE_CODE (vr0
.max
) == INTEGER_CST
2525 && !is_overflow_infinity (vr0
.min
)
2526 && !is_overflow_infinity (vr0
.max
)
2527 && (TYPE_PRECISION (outer_type
) >= TYPE_PRECISION (inner_type
)
2528 || (vr0
.type
== VR_RANGE
2529 && integer_zerop (int_const_binop (RSHIFT_EXPR
,
2530 int_const_binop (MINUS_EXPR
, vr0
.max
, vr0
.min
, 0),
2531 size_int (TYPE_PRECISION (outer_type
)), 0)))))
2533 tree new_min
, new_max
;
2534 new_min
= force_fit_type_double (outer_type
,
2535 TREE_INT_CST_LOW (vr0
.min
),
2536 TREE_INT_CST_HIGH (vr0
.min
), 0, 0);
2537 new_max
= force_fit_type_double (outer_type
,
2538 TREE_INT_CST_LOW (vr0
.max
),
2539 TREE_INT_CST_HIGH (vr0
.max
), 0, 0);
2540 set_and_canonicalize_value_range (vr
, vr0
.type
,
2541 new_min
, new_max
, NULL
);
2545 set_value_range_to_varying (vr
);
2549 /* Conversion of a VR_VARYING value to a wider type can result
2550 in a usable range. So wait until after we've handled conversions
2551 before dropping the result to VR_VARYING if we had a source
2552 operand that is VR_VARYING. */
2553 if (vr0
.type
== VR_VARYING
)
2555 set_value_range_to_varying (vr
);
2559 /* Apply the operation to each end of the range and see what we end
2561 if (code
== NEGATE_EXPR
2562 && !TYPE_UNSIGNED (type
))
2564 /* NEGATE_EXPR flips the range around. We need to treat
2565 TYPE_MIN_VALUE specially. */
2566 if (is_positive_overflow_infinity (vr0
.max
))
2567 min
= negative_overflow_infinity (type
);
2568 else if (is_negative_overflow_infinity (vr0
.max
))
2569 min
= positive_overflow_infinity (type
);
2570 else if (!vrp_val_is_min (vr0
.max
))
2571 min
= fold_unary_to_constant (code
, type
, vr0
.max
);
2572 else if (needs_overflow_infinity (type
))
2574 if (supports_overflow_infinity (type
)
2575 && !is_overflow_infinity (vr0
.min
)
2576 && !vrp_val_is_min (vr0
.min
))
2577 min
= positive_overflow_infinity (type
);
2580 set_value_range_to_varying (vr
);
2585 min
= TYPE_MIN_VALUE (type
);
2587 if (is_positive_overflow_infinity (vr0
.min
))
2588 max
= negative_overflow_infinity (type
);
2589 else if (is_negative_overflow_infinity (vr0
.min
))
2590 max
= positive_overflow_infinity (type
);
2591 else if (!vrp_val_is_min (vr0
.min
))
2592 max
= fold_unary_to_constant (code
, type
, vr0
.min
);
2593 else if (needs_overflow_infinity (type
))
2595 if (supports_overflow_infinity (type
))
2596 max
= positive_overflow_infinity (type
);
2599 set_value_range_to_varying (vr
);
2604 max
= TYPE_MIN_VALUE (type
);
2606 else if (code
== NEGATE_EXPR
2607 && TYPE_UNSIGNED (type
))
2609 if (!range_includes_zero_p (&vr0
))
2611 max
= fold_unary_to_constant (code
, type
, vr0
.min
);
2612 min
= fold_unary_to_constant (code
, type
, vr0
.max
);
2616 if (range_is_null (&vr0
))
2617 set_value_range_to_null (vr
, type
);
2619 set_value_range_to_varying (vr
);
2623 else if (code
== ABS_EXPR
2624 && !TYPE_UNSIGNED (type
))
2626 /* -TYPE_MIN_VALUE = TYPE_MIN_VALUE with flag_wrapv so we can't get a
2628 if (!TYPE_OVERFLOW_UNDEFINED (type
)
2629 && ((vr0
.type
== VR_RANGE
2630 && vrp_val_is_min (vr0
.min
))
2631 || (vr0
.type
== VR_ANTI_RANGE
2632 && !vrp_val_is_min (vr0
.min
)
2633 && !range_includes_zero_p (&vr0
))))
2635 set_value_range_to_varying (vr
);
2639 /* ABS_EXPR may flip the range around, if the original range
2640 included negative values. */
2641 if (is_overflow_infinity (vr0
.min
))
2642 min
= positive_overflow_infinity (type
);
2643 else if (!vrp_val_is_min (vr0
.min
))
2644 min
= fold_unary_to_constant (code
, type
, vr0
.min
);
2645 else if (!needs_overflow_infinity (type
))
2646 min
= TYPE_MAX_VALUE (type
);
2647 else if (supports_overflow_infinity (type
))
2648 min
= positive_overflow_infinity (type
);
2651 set_value_range_to_varying (vr
);
2655 if (is_overflow_infinity (vr0
.max
))
2656 max
= positive_overflow_infinity (type
);
2657 else if (!vrp_val_is_min (vr0
.max
))
2658 max
= fold_unary_to_constant (code
, type
, vr0
.max
);
2659 else if (!needs_overflow_infinity (type
))
2660 max
= TYPE_MAX_VALUE (type
);
2661 else if (supports_overflow_infinity (type
))
2662 max
= positive_overflow_infinity (type
);
2665 set_value_range_to_varying (vr
);
2669 cmp
= compare_values (min
, max
);
2671 /* If a VR_ANTI_RANGEs contains zero, then we have
2672 ~[-INF, min(MIN, MAX)]. */
2673 if (vr0
.type
== VR_ANTI_RANGE
)
2675 if (range_includes_zero_p (&vr0
))
2677 /* Take the lower of the two values. */
2681 /* Create ~[-INF, min (abs(MIN), abs(MAX))]
2682 or ~[-INF + 1, min (abs(MIN), abs(MAX))] when
2683 flag_wrapv is set and the original anti-range doesn't include
2684 TYPE_MIN_VALUE, remember -TYPE_MIN_VALUE = TYPE_MIN_VALUE. */
2685 if (TYPE_OVERFLOW_WRAPS (type
))
2687 tree type_min_value
= TYPE_MIN_VALUE (type
);
2689 min
= (vr0
.min
!= type_min_value
2690 ? int_const_binop (PLUS_EXPR
, type_min_value
,
2691 integer_one_node
, 0)
2696 if (overflow_infinity_range_p (&vr0
))
2697 min
= negative_overflow_infinity (type
);
2699 min
= TYPE_MIN_VALUE (type
);
2704 /* All else has failed, so create the range [0, INF], even for
2705 flag_wrapv since TYPE_MIN_VALUE is in the original
2707 vr0
.type
= VR_RANGE
;
2708 min
= build_int_cst (type
, 0);
2709 if (needs_overflow_infinity (type
))
2711 if (supports_overflow_infinity (type
))
2712 max
= positive_overflow_infinity (type
);
2715 set_value_range_to_varying (vr
);
2720 max
= TYPE_MAX_VALUE (type
);
2724 /* If the range contains zero then we know that the minimum value in the
2725 range will be zero. */
2726 else if (range_includes_zero_p (&vr0
))
2730 min
= build_int_cst (type
, 0);
2734 /* If the range was reversed, swap MIN and MAX. */
2745 /* Otherwise, operate on each end of the range. */
2746 min
= fold_unary_to_constant (code
, type
, vr0
.min
);
2747 max
= fold_unary_to_constant (code
, type
, vr0
.max
);
2749 if (needs_overflow_infinity (type
))
2751 gcc_assert (code
!= NEGATE_EXPR
&& code
!= ABS_EXPR
);
2753 /* If both sides have overflowed, we don't know
2755 if ((is_overflow_infinity (vr0
.min
)
2756 || TREE_OVERFLOW (min
))
2757 && (is_overflow_infinity (vr0
.max
)
2758 || TREE_OVERFLOW (max
)))
2760 set_value_range_to_varying (vr
);
2764 if (is_overflow_infinity (vr0
.min
))
2766 else if (TREE_OVERFLOW (min
))
2768 if (supports_overflow_infinity (type
))
2769 min
= (tree_int_cst_sgn (min
) >= 0
2770 ? positive_overflow_infinity (TREE_TYPE (min
))
2771 : negative_overflow_infinity (TREE_TYPE (min
)));
2774 set_value_range_to_varying (vr
);
2779 if (is_overflow_infinity (vr0
.max
))
2781 else if (TREE_OVERFLOW (max
))
2783 if (supports_overflow_infinity (type
))
2784 max
= (tree_int_cst_sgn (max
) >= 0
2785 ? positive_overflow_infinity (TREE_TYPE (max
))
2786 : negative_overflow_infinity (TREE_TYPE (max
)));
2789 set_value_range_to_varying (vr
);
2796 cmp
= compare_values (min
, max
);
2797 if (cmp
== -2 || cmp
== 1)
2799 /* If the new range has its limits swapped around (MIN > MAX),
2800 then the operation caused one of them to wrap around, mark
2801 the new range VARYING. */
2802 set_value_range_to_varying (vr
);
2805 set_value_range (vr
, vr0
.type
, min
, max
, NULL
);
2809 /* Extract range information from a conditional expression EXPR based on
2810 the ranges of each of its operands and the expression code. */
2813 extract_range_from_cond_expr (value_range_t
*vr
, tree expr
)
2816 value_range_t vr0
= { VR_UNDEFINED
, NULL_TREE
, NULL_TREE
, NULL
};
2817 value_range_t vr1
= { VR_UNDEFINED
, NULL_TREE
, NULL_TREE
, NULL
};
2819 /* Get value ranges for each operand. For constant operands, create
2820 a new value range with the operand to simplify processing. */
2821 op0
= COND_EXPR_THEN (expr
);
2822 if (TREE_CODE (op0
) == SSA_NAME
)
2823 vr0
= *(get_value_range (op0
));
2824 else if (is_gimple_min_invariant (op0
))
2825 set_value_range_to_value (&vr0
, op0
, NULL
);
2827 set_value_range_to_varying (&vr0
);
2829 op1
= COND_EXPR_ELSE (expr
);
2830 if (TREE_CODE (op1
) == SSA_NAME
)
2831 vr1
= *(get_value_range (op1
));
2832 else if (is_gimple_min_invariant (op1
))
2833 set_value_range_to_value (&vr1
, op1
, NULL
);
2835 set_value_range_to_varying (&vr1
);
2837 /* The resulting value range is the union of the operand ranges */
2838 vrp_meet (&vr0
, &vr1
);
2839 copy_value_range (vr
, &vr0
);
2843 /* Extract range information from a comparison expression EXPR based
2844 on the range of its operand and the expression code. */
2847 extract_range_from_comparison (value_range_t
*vr
, enum tree_code code
,
2848 tree type
, tree op0
, tree op1
)
2853 val
= vrp_evaluate_conditional_warnv_with_ops (code
, op0
, op1
, false, &sop
);
2855 /* A disadvantage of using a special infinity as an overflow
2856 representation is that we lose the ability to record overflow
2857 when we don't have an infinity. So we have to ignore a result
2858 which relies on overflow. */
2860 if (val
&& !is_overflow_infinity (val
) && !sop
)
2862 /* Since this expression was found on the RHS of an assignment,
2863 its type may be different from _Bool. Convert VAL to EXPR's
2865 val
= fold_convert (type
, val
);
2866 if (is_gimple_min_invariant (val
))
2867 set_value_range_to_value (vr
, val
, vr
->equiv
);
2869 set_value_range (vr
, VR_RANGE
, val
, val
, vr
->equiv
);
2872 /* The result of a comparison is always true or false. */
2873 set_value_range_to_truthvalue (vr
, type
);
2876 /* Try to derive a nonnegative or nonzero range out of STMT relying
2877 primarily on generic routines in fold in conjunction with range data.
2878 Store the result in *VR */
2881 extract_range_basic (value_range_t
*vr
, gimple stmt
)
2884 tree type
= gimple_expr_type (stmt
);
2886 if (INTEGRAL_TYPE_P (type
)
2887 && gimple_stmt_nonnegative_warnv_p (stmt
, &sop
))
2888 set_value_range_to_nonnegative (vr
, type
,
2889 sop
|| stmt_overflow_infinity (stmt
));
2890 else if (vrp_stmt_computes_nonzero (stmt
, &sop
)
2892 set_value_range_to_nonnull (vr
, type
);
2894 set_value_range_to_varying (vr
);
2898 /* Try to compute a useful range out of assignment STMT and store it
2902 extract_range_from_assignment (value_range_t
*vr
, gimple stmt
)
2904 enum tree_code code
= gimple_assign_rhs_code (stmt
);
2906 if (code
== ASSERT_EXPR
)
2907 extract_range_from_assert (vr
, gimple_assign_rhs1 (stmt
));
2908 else if (code
== SSA_NAME
)
2909 extract_range_from_ssa_name (vr
, gimple_assign_rhs1 (stmt
));
2910 else if (TREE_CODE_CLASS (code
) == tcc_binary
2911 || code
== TRUTH_AND_EXPR
2912 || code
== TRUTH_OR_EXPR
2913 || code
== TRUTH_XOR_EXPR
)
2914 extract_range_from_binary_expr (vr
, gimple_assign_rhs_code (stmt
),
2915 gimple_expr_type (stmt
),
2916 gimple_assign_rhs1 (stmt
),
2917 gimple_assign_rhs2 (stmt
));
2918 else if (TREE_CODE_CLASS (code
) == tcc_unary
)
2919 extract_range_from_unary_expr (vr
, gimple_assign_rhs_code (stmt
),
2920 gimple_expr_type (stmt
),
2921 gimple_assign_rhs1 (stmt
));
2922 else if (code
== COND_EXPR
)
2923 extract_range_from_cond_expr (vr
, gimple_assign_rhs1 (stmt
));
2924 else if (TREE_CODE_CLASS (code
) == tcc_comparison
)
2925 extract_range_from_comparison (vr
, gimple_assign_rhs_code (stmt
),
2926 gimple_expr_type (stmt
),
2927 gimple_assign_rhs1 (stmt
),
2928 gimple_assign_rhs2 (stmt
));
2929 else if (get_gimple_rhs_class (code
) == GIMPLE_SINGLE_RHS
2930 && is_gimple_min_invariant (gimple_assign_rhs1 (stmt
)))
2931 set_value_range_to_value (vr
, gimple_assign_rhs1 (stmt
), NULL
);
2933 set_value_range_to_varying (vr
);
2935 if (vr
->type
== VR_VARYING
)
2936 extract_range_basic (vr
, stmt
);
2939 /* Given a range VR, a LOOP and a variable VAR, determine whether it
2940 would be profitable to adjust VR using scalar evolution information
2941 for VAR. If so, update VR with the new limits. */
2944 adjust_range_with_scev (value_range_t
*vr
, struct loop
*loop
,
2945 gimple stmt
, tree var
)
2947 tree init
, step
, chrec
, tmin
, tmax
, min
, max
, type
;
2948 enum ev_direction dir
;
2950 /* TODO. Don't adjust anti-ranges. An anti-range may provide
2951 better opportunities than a regular range, but I'm not sure. */
2952 if (vr
->type
== VR_ANTI_RANGE
)
2955 chrec
= instantiate_parameters (loop
, analyze_scalar_evolution (loop
, var
));
2957 /* Like in PR19590, scev can return a constant function. */
2958 if (is_gimple_min_invariant (chrec
))
2960 set_value_range_to_value (vr
, chrec
, vr
->equiv
);
2964 if (TREE_CODE (chrec
) != POLYNOMIAL_CHREC
)
2967 init
= initial_condition_in_loop_num (chrec
, loop
->num
);
2968 step
= evolution_part_in_loop_num (chrec
, loop
->num
);
2970 /* If STEP is symbolic, we can't know whether INIT will be the
2971 minimum or maximum value in the range. Also, unless INIT is
2972 a simple expression, compare_values and possibly other functions
2973 in tree-vrp won't be able to handle it. */
2974 if (step
== NULL_TREE
2975 || !is_gimple_min_invariant (step
)
2976 || !valid_value_p (init
))
2979 dir
= scev_direction (chrec
);
2980 if (/* Do not adjust ranges if we do not know whether the iv increases
2981 or decreases, ... */
2982 dir
== EV_DIR_UNKNOWN
2983 /* ... or if it may wrap. */
2984 || scev_probably_wraps_p (init
, step
, stmt
, get_chrec_loop (chrec
),
2988 /* We use TYPE_MIN_VALUE and TYPE_MAX_VALUE here instead of
2989 negative_overflow_infinity and positive_overflow_infinity,
2990 because we have concluded that the loop probably does not
2993 type
= TREE_TYPE (var
);
2994 if (POINTER_TYPE_P (type
) || !TYPE_MIN_VALUE (type
))
2995 tmin
= lower_bound_in_type (type
, type
);
2997 tmin
= TYPE_MIN_VALUE (type
);
2998 if (POINTER_TYPE_P (type
) || !TYPE_MAX_VALUE (type
))
2999 tmax
= upper_bound_in_type (type
, type
);
3001 tmax
= TYPE_MAX_VALUE (type
);
3003 if (vr
->type
== VR_VARYING
|| vr
->type
== VR_UNDEFINED
)
3008 /* For VARYING or UNDEFINED ranges, just about anything we get
3009 from scalar evolutions should be better. */
3011 if (dir
== EV_DIR_DECREASES
)
3016 /* If we would create an invalid range, then just assume we
3017 know absolutely nothing. This may be over-conservative,
3018 but it's clearly safe, and should happen only in unreachable
3019 parts of code, or for invalid programs. */
3020 if (compare_values (min
, max
) == 1)
3023 set_value_range (vr
, VR_RANGE
, min
, max
, vr
->equiv
);
3025 else if (vr
->type
== VR_RANGE
)
3030 if (dir
== EV_DIR_DECREASES
)
3032 /* INIT is the maximum value. If INIT is lower than VR->MAX
3033 but no smaller than VR->MIN, set VR->MAX to INIT. */
3034 if (compare_values (init
, max
) == -1)
3038 /* If we just created an invalid range with the minimum
3039 greater than the maximum, we fail conservatively.
3040 This should happen only in unreachable
3041 parts of code, or for invalid programs. */
3042 if (compare_values (min
, max
) == 1)
3046 /* According to the loop information, the variable does not
3047 overflow. If we think it does, probably because of an
3048 overflow due to arithmetic on a different INF value,
3050 if (is_negative_overflow_infinity (min
))
3055 /* If INIT is bigger than VR->MIN, set VR->MIN to INIT. */
3056 if (compare_values (init
, min
) == 1)
3060 /* Again, avoid creating invalid range by failing. */
3061 if (compare_values (min
, max
) == 1)
3065 if (is_positive_overflow_infinity (max
))
3069 set_value_range (vr
, VR_RANGE
, min
, max
, vr
->equiv
);
3073 /* Return true if VAR may overflow at STMT. This checks any available
3074 loop information to see if we can determine that VAR does not
3078 vrp_var_may_overflow (tree var
, gimple stmt
)
3081 tree chrec
, init
, step
;
3083 if (current_loops
== NULL
)
3086 l
= loop_containing_stmt (stmt
);
3090 chrec
= instantiate_parameters (l
, analyze_scalar_evolution (l
, var
));
3091 if (TREE_CODE (chrec
) != POLYNOMIAL_CHREC
)
3094 init
= initial_condition_in_loop_num (chrec
, l
->num
);
3095 step
= evolution_part_in_loop_num (chrec
, l
->num
);
3097 if (step
== NULL_TREE
3098 || !is_gimple_min_invariant (step
)
3099 || !valid_value_p (init
))
3102 /* If we get here, we know something useful about VAR based on the
3103 loop information. If it wraps, it may overflow. */
3105 if (scev_probably_wraps_p (init
, step
, stmt
, get_chrec_loop (chrec
),
3109 if (dump_file
&& (dump_flags
& TDF_DETAILS
) != 0)
3111 print_generic_expr (dump_file
, var
, 0);
3112 fprintf (dump_file
, ": loop information indicates does not overflow\n");
3119 /* Given two numeric value ranges VR0, VR1 and a comparison code COMP:
3121 - Return BOOLEAN_TRUE_NODE if VR0 COMP VR1 always returns true for
3122 all the values in the ranges.
3124 - Return BOOLEAN_FALSE_NODE if the comparison always returns false.
3126 - Return NULL_TREE if it is not always possible to determine the
3127 value of the comparison.
3129 Also set *STRICT_OVERFLOW_P to indicate whether a range with an
3130 overflow infinity was used in the test. */
3134 compare_ranges (enum tree_code comp
, value_range_t
*vr0
, value_range_t
*vr1
,
3135 bool *strict_overflow_p
)
3137 /* VARYING or UNDEFINED ranges cannot be compared. */
3138 if (vr0
->type
== VR_VARYING
3139 || vr0
->type
== VR_UNDEFINED
3140 || vr1
->type
== VR_VARYING
3141 || vr1
->type
== VR_UNDEFINED
)
3144 /* Anti-ranges need to be handled separately. */
3145 if (vr0
->type
== VR_ANTI_RANGE
|| vr1
->type
== VR_ANTI_RANGE
)
3147 /* If both are anti-ranges, then we cannot compute any
3149 if (vr0
->type
== VR_ANTI_RANGE
&& vr1
->type
== VR_ANTI_RANGE
)
3152 /* These comparisons are never statically computable. */
3159 /* Equality can be computed only between a range and an
3160 anti-range. ~[VAL1, VAL2] == [VAL1, VAL2] is always false. */
3161 if (vr0
->type
== VR_RANGE
)
3163 /* To simplify processing, make VR0 the anti-range. */
3164 value_range_t
*tmp
= vr0
;
3169 gcc_assert (comp
== NE_EXPR
|| comp
== EQ_EXPR
);
3171 if (compare_values_warnv (vr0
->min
, vr1
->min
, strict_overflow_p
) == 0
3172 && compare_values_warnv (vr0
->max
, vr1
->max
, strict_overflow_p
) == 0)
3173 return (comp
== NE_EXPR
) ? boolean_true_node
: boolean_false_node
;
3178 if (!usable_range_p (vr0
, strict_overflow_p
)
3179 || !usable_range_p (vr1
, strict_overflow_p
))
3182 /* Simplify processing. If COMP is GT_EXPR or GE_EXPR, switch the
3183 operands around and change the comparison code. */
3184 if (comp
== GT_EXPR
|| comp
== GE_EXPR
)
3187 comp
= (comp
== GT_EXPR
) ? LT_EXPR
: LE_EXPR
;
3193 if (comp
== EQ_EXPR
)
3195 /* Equality may only be computed if both ranges represent
3196 exactly one value. */
3197 if (compare_values_warnv (vr0
->min
, vr0
->max
, strict_overflow_p
) == 0
3198 && compare_values_warnv (vr1
->min
, vr1
->max
, strict_overflow_p
) == 0)
3200 int cmp_min
= compare_values_warnv (vr0
->min
, vr1
->min
,
3202 int cmp_max
= compare_values_warnv (vr0
->max
, vr1
->max
,
3204 if (cmp_min
== 0 && cmp_max
== 0)
3205 return boolean_true_node
;
3206 else if (cmp_min
!= -2 && cmp_max
!= -2)
3207 return boolean_false_node
;
3209 /* If [V0_MIN, V1_MAX] < [V1_MIN, V1_MAX] then V0 != V1. */
3210 else if (compare_values_warnv (vr0
->min
, vr1
->max
,
3211 strict_overflow_p
) == 1
3212 || compare_values_warnv (vr1
->min
, vr0
->max
,
3213 strict_overflow_p
) == 1)
3214 return boolean_false_node
;
3218 else if (comp
== NE_EXPR
)
3222 /* If VR0 is completely to the left or completely to the right
3223 of VR1, they are always different. Notice that we need to
3224 make sure that both comparisons yield similar results to
3225 avoid comparing values that cannot be compared at
3227 cmp1
= compare_values_warnv (vr0
->max
, vr1
->min
, strict_overflow_p
);
3228 cmp2
= compare_values_warnv (vr0
->min
, vr1
->max
, strict_overflow_p
);
3229 if ((cmp1
== -1 && cmp2
== -1) || (cmp1
== 1 && cmp2
== 1))
3230 return boolean_true_node
;
3232 /* If VR0 and VR1 represent a single value and are identical,
3234 else if (compare_values_warnv (vr0
->min
, vr0
->max
,
3235 strict_overflow_p
) == 0
3236 && compare_values_warnv (vr1
->min
, vr1
->max
,
3237 strict_overflow_p
) == 0
3238 && compare_values_warnv (vr0
->min
, vr1
->min
,
3239 strict_overflow_p
) == 0
3240 && compare_values_warnv (vr0
->max
, vr1
->max
,
3241 strict_overflow_p
) == 0)
3242 return boolean_false_node
;
3244 /* Otherwise, they may or may not be different. */
3248 else if (comp
== LT_EXPR
|| comp
== LE_EXPR
)
3252 /* If VR0 is to the left of VR1, return true. */
3253 tst
= compare_values_warnv (vr0
->max
, vr1
->min
, strict_overflow_p
);
3254 if ((comp
== LT_EXPR
&& tst
== -1)
3255 || (comp
== LE_EXPR
&& (tst
== -1 || tst
== 0)))
3257 if (overflow_infinity_range_p (vr0
)
3258 || overflow_infinity_range_p (vr1
))
3259 *strict_overflow_p
= true;
3260 return boolean_true_node
;
3263 /* If VR0 is to the right of VR1, return false. */
3264 tst
= compare_values_warnv (vr0
->min
, vr1
->max
, strict_overflow_p
);
3265 if ((comp
== LT_EXPR
&& (tst
== 0 || tst
== 1))
3266 || (comp
== LE_EXPR
&& tst
== 1))
3268 if (overflow_infinity_range_p (vr0
)
3269 || overflow_infinity_range_p (vr1
))
3270 *strict_overflow_p
= true;
3271 return boolean_false_node
;
3274 /* Otherwise, we don't know. */
3282 /* Given a value range VR, a value VAL and a comparison code COMP, return
3283 BOOLEAN_TRUE_NODE if VR COMP VAL always returns true for all the
3284 values in VR. Return BOOLEAN_FALSE_NODE if the comparison
3285 always returns false. Return NULL_TREE if it is not always
3286 possible to determine the value of the comparison. Also set
3287 *STRICT_OVERFLOW_P to indicate whether a range with an overflow
3288 infinity was used in the test. */
3291 compare_range_with_value (enum tree_code comp
, value_range_t
*vr
, tree val
,
3292 bool *strict_overflow_p
)
3294 if (vr
->type
== VR_VARYING
|| vr
->type
== VR_UNDEFINED
)
3297 /* Anti-ranges need to be handled separately. */
3298 if (vr
->type
== VR_ANTI_RANGE
)
3300 /* For anti-ranges, the only predicates that we can compute at
3301 compile time are equality and inequality. */
3308 /* ~[VAL_1, VAL_2] OP VAL is known if VAL_1 <= VAL <= VAL_2. */
3309 if (value_inside_range (val
, vr
) == 1)
3310 return (comp
== NE_EXPR
) ? boolean_true_node
: boolean_false_node
;
3315 if (!usable_range_p (vr
, strict_overflow_p
))
3318 if (comp
== EQ_EXPR
)
3320 /* EQ_EXPR may only be computed if VR represents exactly
3322 if (compare_values_warnv (vr
->min
, vr
->max
, strict_overflow_p
) == 0)
3324 int cmp
= compare_values_warnv (vr
->min
, val
, strict_overflow_p
);
3326 return boolean_true_node
;
3327 else if (cmp
== -1 || cmp
== 1 || cmp
== 2)
3328 return boolean_false_node
;
3330 else if (compare_values_warnv (val
, vr
->min
, strict_overflow_p
) == -1
3331 || compare_values_warnv (vr
->max
, val
, strict_overflow_p
) == -1)
3332 return boolean_false_node
;
3336 else if (comp
== NE_EXPR
)
3338 /* If VAL is not inside VR, then they are always different. */
3339 if (compare_values_warnv (vr
->max
, val
, strict_overflow_p
) == -1
3340 || compare_values_warnv (vr
->min
, val
, strict_overflow_p
) == 1)
3341 return boolean_true_node
;
3343 /* If VR represents exactly one value equal to VAL, then return
3345 if (compare_values_warnv (vr
->min
, vr
->max
, strict_overflow_p
) == 0
3346 && compare_values_warnv (vr
->min
, val
, strict_overflow_p
) == 0)
3347 return boolean_false_node
;
3349 /* Otherwise, they may or may not be different. */
3352 else if (comp
== LT_EXPR
|| comp
== LE_EXPR
)
3356 /* If VR is to the left of VAL, return true. */
3357 tst
= compare_values_warnv (vr
->max
, val
, strict_overflow_p
);
3358 if ((comp
== LT_EXPR
&& tst
== -1)
3359 || (comp
== LE_EXPR
&& (tst
== -1 || tst
== 0)))
3361 if (overflow_infinity_range_p (vr
))
3362 *strict_overflow_p
= true;
3363 return boolean_true_node
;
3366 /* If VR is to the right of VAL, return false. */
3367 tst
= compare_values_warnv (vr
->min
, val
, strict_overflow_p
);
3368 if ((comp
== LT_EXPR
&& (tst
== 0 || tst
== 1))
3369 || (comp
== LE_EXPR
&& tst
== 1))
3371 if (overflow_infinity_range_p (vr
))
3372 *strict_overflow_p
= true;
3373 return boolean_false_node
;
3376 /* Otherwise, we don't know. */
3379 else if (comp
== GT_EXPR
|| comp
== GE_EXPR
)
3383 /* If VR is to the right of VAL, return true. */
3384 tst
= compare_values_warnv (vr
->min
, val
, strict_overflow_p
);
3385 if ((comp
== GT_EXPR
&& tst
== 1)
3386 || (comp
== GE_EXPR
&& (tst
== 0 || tst
== 1)))
3388 if (overflow_infinity_range_p (vr
))
3389 *strict_overflow_p
= true;
3390 return boolean_true_node
;
3393 /* If VR is to the left of VAL, return false. */
3394 tst
= compare_values_warnv (vr
->max
, val
, strict_overflow_p
);
3395 if ((comp
== GT_EXPR
&& (tst
== -1 || tst
== 0))
3396 || (comp
== GE_EXPR
&& tst
== -1))
3398 if (overflow_infinity_range_p (vr
))
3399 *strict_overflow_p
= true;
3400 return boolean_false_node
;
3403 /* Otherwise, we don't know. */
3411 /* Debugging dumps. */
3413 void dump_value_range (FILE *, value_range_t
*);
3414 void debug_value_range (value_range_t
*);
3415 void dump_all_value_ranges (FILE *);
3416 void debug_all_value_ranges (void);
3417 void dump_vr_equiv (FILE *, bitmap
);
3418 void debug_vr_equiv (bitmap
);
3421 /* Dump value range VR to FILE. */
3424 dump_value_range (FILE *file
, value_range_t
*vr
)
3427 fprintf (file
, "[]");
3428 else if (vr
->type
== VR_UNDEFINED
)
3429 fprintf (file
, "UNDEFINED");
3430 else if (vr
->type
== VR_RANGE
|| vr
->type
== VR_ANTI_RANGE
)
3432 tree type
= TREE_TYPE (vr
->min
);
3434 fprintf (file
, "%s[", (vr
->type
== VR_ANTI_RANGE
) ? "~" : "");
3436 if (is_negative_overflow_infinity (vr
->min
))
3437 fprintf (file
, "-INF(OVF)");
3438 else if (INTEGRAL_TYPE_P (type
)
3439 && !TYPE_UNSIGNED (type
)
3440 && vrp_val_is_min (vr
->min
))
3441 fprintf (file
, "-INF");
3443 print_generic_expr (file
, vr
->min
, 0);
3445 fprintf (file
, ", ");
3447 if (is_positive_overflow_infinity (vr
->max
))
3448 fprintf (file
, "+INF(OVF)");
3449 else if (INTEGRAL_TYPE_P (type
)
3450 && vrp_val_is_max (vr
->max
))
3451 fprintf (file
, "+INF");
3453 print_generic_expr (file
, vr
->max
, 0);
3455 fprintf (file
, "]");
3462 fprintf (file
, " EQUIVALENCES: { ");
3464 EXECUTE_IF_SET_IN_BITMAP (vr
->equiv
, 0, i
, bi
)
3466 print_generic_expr (file
, ssa_name (i
), 0);
3467 fprintf (file
, " ");
3471 fprintf (file
, "} (%u elements)", c
);
3474 else if (vr
->type
== VR_VARYING
)
3475 fprintf (file
, "VARYING");
3477 fprintf (file
, "INVALID RANGE");
3481 /* Dump value range VR to stderr. */
3484 debug_value_range (value_range_t
*vr
)
3486 dump_value_range (stderr
, vr
);
3487 fprintf (stderr
, "\n");
3491 /* Dump value ranges of all SSA_NAMEs to FILE. */
3494 dump_all_value_ranges (FILE *file
)
3498 for (i
= 0; i
< num_ssa_names
; i
++)
3502 print_generic_expr (file
, ssa_name (i
), 0);
3503 fprintf (file
, ": ");
3504 dump_value_range (file
, vr_value
[i
]);
3505 fprintf (file
, "\n");
3509 fprintf (file
, "\n");
3513 /* Dump all value ranges to stderr. */
3516 debug_all_value_ranges (void)
3518 dump_all_value_ranges (stderr
);
3522 /* Given a COND_EXPR COND of the form 'V OP W', and an SSA name V,
3523 create a new SSA name N and return the assertion assignment
3524 'V = ASSERT_EXPR <V, V OP W>'. */
3527 build_assert_expr_for (tree cond
, tree v
)
3532 gcc_assert (TREE_CODE (v
) == SSA_NAME
);
3533 n
= duplicate_ssa_name (v
, NULL
);
3535 if (COMPARISON_CLASS_P (cond
))
3537 tree a
= build2 (ASSERT_EXPR
, TREE_TYPE (v
), v
, cond
);
3538 assertion
= gimple_build_assign (n
, a
);
3540 else if (TREE_CODE (cond
) == TRUTH_NOT_EXPR
)
3542 /* Given !V, build the assignment N = false. */
3543 tree op0
= TREE_OPERAND (cond
, 0);
3544 gcc_assert (op0
== v
);
3545 assertion
= gimple_build_assign (n
, boolean_false_node
);
3547 else if (TREE_CODE (cond
) == SSA_NAME
)
3549 /* Given V, build the assignment N = true. */
3550 gcc_assert (v
== cond
);
3551 assertion
= gimple_build_assign (n
, boolean_true_node
);
3556 SSA_NAME_DEF_STMT (n
) = assertion
;
3558 /* The new ASSERT_EXPR, creates a new SSA name that replaces the
3559 operand of the ASSERT_EXPR. Register the new name and the old one
3560 in the replacement table so that we can fix the SSA web after
3561 adding all the ASSERT_EXPRs. */
3562 register_new_name_mapping (n
, v
);
3568 /* Return false if EXPR is a predicate expression involving floating
3572 fp_predicate (gimple stmt
)
3574 GIMPLE_CHECK (stmt
, GIMPLE_COND
);
3576 return FLOAT_TYPE_P (TREE_TYPE (gimple_cond_lhs (stmt
)));
3580 /* If the range of values taken by OP can be inferred after STMT executes,
3581 return the comparison code (COMP_CODE_P) and value (VAL_P) that
3582 describes the inferred range. Return true if a range could be
3586 infer_value_range (gimple stmt
, tree op
, enum tree_code
*comp_code_p
, tree
*val_p
)
3589 *comp_code_p
= ERROR_MARK
;
3591 /* Do not attempt to infer anything in names that flow through
3593 if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (op
))
3596 /* Similarly, don't infer anything from statements that may throw
3598 if (stmt_could_throw_p (stmt
))
3601 /* If STMT is the last statement of a basic block with no
3602 successors, there is no point inferring anything about any of its
3603 operands. We would not be able to find a proper insertion point
3604 for the assertion, anyway. */
3605 if (stmt_ends_bb_p (stmt
) && EDGE_COUNT (gimple_bb (stmt
)->succs
) == 0)
3608 /* We can only assume that a pointer dereference will yield
3609 non-NULL if -fdelete-null-pointer-checks is enabled. */
3610 if (flag_delete_null_pointer_checks
3611 && POINTER_TYPE_P (TREE_TYPE (op
))
3612 && gimple_code (stmt
) != GIMPLE_ASM
)
3614 unsigned num_uses
, num_loads
, num_stores
;
3616 count_uses_and_derefs (op
, stmt
, &num_uses
, &num_loads
, &num_stores
);
3617 if (num_loads
+ num_stores
> 0)
3619 *val_p
= build_int_cst (TREE_TYPE (op
), 0);
3620 *comp_code_p
= NE_EXPR
;
3629 void dump_asserts_for (FILE *, tree
);
3630 void debug_asserts_for (tree
);
3631 void dump_all_asserts (FILE *);
3632 void debug_all_asserts (void);
3634 /* Dump all the registered assertions for NAME to FILE. */
3637 dump_asserts_for (FILE *file
, tree name
)
3641 fprintf (file
, "Assertions to be inserted for ");
3642 print_generic_expr (file
, name
, 0);
3643 fprintf (file
, "\n");
3645 loc
= asserts_for
[SSA_NAME_VERSION (name
)];
3648 fprintf (file
, "\t");
3649 print_gimple_stmt (file
, gsi_stmt (loc
->si
), 0, 0);
3650 fprintf (file
, "\n\tBB #%d", loc
->bb
->index
);
3653 fprintf (file
, "\n\tEDGE %d->%d", loc
->e
->src
->index
,
3654 loc
->e
->dest
->index
);
3655 dump_edge_info (file
, loc
->e
, 0);
3657 fprintf (file
, "\n\tPREDICATE: ");
3658 print_generic_expr (file
, name
, 0);
3659 fprintf (file
, " %s ", tree_code_name
[(int)loc
->comp_code
]);
3660 print_generic_expr (file
, loc
->val
, 0);
3661 fprintf (file
, "\n\n");
3665 fprintf (file
, "\n");
3669 /* Dump all the registered assertions for NAME to stderr. */
3672 debug_asserts_for (tree name
)
3674 dump_asserts_for (stderr
, name
);
3678 /* Dump all the registered assertions for all the names to FILE. */
3681 dump_all_asserts (FILE *file
)
3686 fprintf (file
, "\nASSERT_EXPRs to be inserted\n\n");
3687 EXECUTE_IF_SET_IN_BITMAP (need_assert_for
, 0, i
, bi
)
3688 dump_asserts_for (file
, ssa_name (i
));
3689 fprintf (file
, "\n");
3693 /* Dump all the registered assertions for all the names to stderr. */
3696 debug_all_asserts (void)
3698 dump_all_asserts (stderr
);
3702 /* If NAME doesn't have an ASSERT_EXPR registered for asserting
3703 'EXPR COMP_CODE VAL' at a location that dominates block BB or
3704 E->DEST, then register this location as a possible insertion point
3705 for ASSERT_EXPR <NAME, EXPR COMP_CODE VAL>.
3707 BB, E and SI provide the exact insertion point for the new
3708 ASSERT_EXPR. If BB is NULL, then the ASSERT_EXPR is to be inserted
3709 on edge E. Otherwise, if E is NULL, the ASSERT_EXPR is inserted on
3710 BB. If SI points to a COND_EXPR or a SWITCH_EXPR statement, then E
3711 must not be NULL. */
3714 register_new_assert_for (tree name
, tree expr
,
3715 enum tree_code comp_code
,
3719 gimple_stmt_iterator si
)
3721 assert_locus_t n
, loc
, last_loc
;
3723 basic_block dest_bb
;
3725 #if defined ENABLE_CHECKING
3726 gcc_assert (bb
== NULL
|| e
== NULL
);
3729 gcc_assert (gimple_code (gsi_stmt (si
)) != GIMPLE_COND
3730 && gimple_code (gsi_stmt (si
)) != GIMPLE_SWITCH
);
3733 /* The new assertion A will be inserted at BB or E. We need to
3734 determine if the new location is dominated by a previously
3735 registered location for A. If we are doing an edge insertion,
3736 assume that A will be inserted at E->DEST. Note that this is not
3739 If E is a critical edge, it will be split. But even if E is
3740 split, the new block will dominate the same set of blocks that
3743 The reverse, however, is not true, blocks dominated by E->DEST
3744 will not be dominated by the new block created to split E. So,
3745 if the insertion location is on a critical edge, we will not use
3746 the new location to move another assertion previously registered
3747 at a block dominated by E->DEST. */
3748 dest_bb
= (bb
) ? bb
: e
->dest
;
3750 /* If NAME already has an ASSERT_EXPR registered for COMP_CODE and
3751 VAL at a block dominating DEST_BB, then we don't need to insert a new
3752 one. Similarly, if the same assertion already exists at a block
3753 dominated by DEST_BB and the new location is not on a critical
3754 edge, then update the existing location for the assertion (i.e.,
3755 move the assertion up in the dominance tree).
3757 Note, this is implemented as a simple linked list because there
3758 should not be more than a handful of assertions registered per
3759 name. If this becomes a performance problem, a table hashed by
3760 COMP_CODE and VAL could be implemented. */
3761 loc
= asserts_for
[SSA_NAME_VERSION (name
)];
3766 if (loc
->comp_code
== comp_code
3768 || operand_equal_p (loc
->val
, val
, 0))
3769 && (loc
->expr
== expr
3770 || operand_equal_p (loc
->expr
, expr
, 0)))
3772 /* If the assertion NAME COMP_CODE VAL has already been
3773 registered at a basic block that dominates DEST_BB, then
3774 we don't need to insert the same assertion again. Note
3775 that we don't check strict dominance here to avoid
3776 replicating the same assertion inside the same basic
3777 block more than once (e.g., when a pointer is
3778 dereferenced several times inside a block).
3780 An exception to this rule are edge insertions. If the
3781 new assertion is to be inserted on edge E, then it will
3782 dominate all the other insertions that we may want to
3783 insert in DEST_BB. So, if we are doing an edge
3784 insertion, don't do this dominance check. */
3786 && dominated_by_p (CDI_DOMINATORS
, dest_bb
, loc
->bb
))
3789 /* Otherwise, if E is not a critical edge and DEST_BB
3790 dominates the existing location for the assertion, move
3791 the assertion up in the dominance tree by updating its
3792 location information. */
3793 if ((e
== NULL
|| !EDGE_CRITICAL_P (e
))
3794 && dominated_by_p (CDI_DOMINATORS
, loc
->bb
, dest_bb
))
3803 /* Update the last node of the list and move to the next one. */
3808 /* If we didn't find an assertion already registered for
3809 NAME COMP_CODE VAL, add a new one at the end of the list of
3810 assertions associated with NAME. */
3811 n
= XNEW (struct assert_locus_d
);
3815 n
->comp_code
= comp_code
;
3823 asserts_for
[SSA_NAME_VERSION (name
)] = n
;
3825 bitmap_set_bit (need_assert_for
, SSA_NAME_VERSION (name
));
3828 /* (COND_OP0 COND_CODE COND_OP1) is a predicate which uses NAME.
3829 Extract a suitable test code and value and store them into *CODE_P and
3830 *VAL_P so the predicate is normalized to NAME *CODE_P *VAL_P.
3832 If no extraction was possible, return FALSE, otherwise return TRUE.
3834 If INVERT is true, then we invert the result stored into *CODE_P. */
3837 extract_code_and_val_from_cond_with_ops (tree name
, enum tree_code cond_code
,
3838 tree cond_op0
, tree cond_op1
,
3839 bool invert
, enum tree_code
*code_p
,
3842 enum tree_code comp_code
;
3845 /* Otherwise, we have a comparison of the form NAME COMP VAL
3846 or VAL COMP NAME. */
3847 if (name
== cond_op1
)
3849 /* If the predicate is of the form VAL COMP NAME, flip
3850 COMP around because we need to register NAME as the
3851 first operand in the predicate. */
3852 comp_code
= swap_tree_comparison (cond_code
);
3857 /* The comparison is of the form NAME COMP VAL, so the
3858 comparison code remains unchanged. */
3859 comp_code
= cond_code
;
3863 /* Invert the comparison code as necessary. */
3865 comp_code
= invert_tree_comparison (comp_code
, 0);
3867 /* VRP does not handle float types. */
3868 if (SCALAR_FLOAT_TYPE_P (TREE_TYPE (val
)))
3871 /* Do not register always-false predicates.
3872 FIXME: this works around a limitation in fold() when dealing with
3873 enumerations. Given 'enum { N1, N2 } x;', fold will not
3874 fold 'if (x > N2)' to 'if (0)'. */
3875 if ((comp_code
== GT_EXPR
|| comp_code
== LT_EXPR
)
3876 && INTEGRAL_TYPE_P (TREE_TYPE (val
)))
3878 tree min
= TYPE_MIN_VALUE (TREE_TYPE (val
));
3879 tree max
= TYPE_MAX_VALUE (TREE_TYPE (val
));
3881 if (comp_code
== GT_EXPR
3883 || compare_values (val
, max
) == 0))
3886 if (comp_code
== LT_EXPR
3888 || compare_values (val
, min
) == 0))
3891 *code_p
= comp_code
;
3896 /* Try to register an edge assertion for SSA name NAME on edge E for
3897 the condition COND contributing to the conditional jump pointed to by BSI.
3898 Invert the condition COND if INVERT is true.
3899 Return true if an assertion for NAME could be registered. */
3902 register_edge_assert_for_2 (tree name
, edge e
, gimple_stmt_iterator bsi
,
3903 enum tree_code cond_code
,
3904 tree cond_op0
, tree cond_op1
, bool invert
)
3907 enum tree_code comp_code
;
3908 bool retval
= false;
3910 if (!extract_code_and_val_from_cond_with_ops (name
, cond_code
,
3913 invert
, &comp_code
, &val
))
3916 /* Only register an ASSERT_EXPR if NAME was found in the sub-graph
3917 reachable from E. */
3918 if (live_on_edge (e
, name
)
3919 && !has_single_use (name
))
3921 register_new_assert_for (name
, name
, comp_code
, val
, NULL
, e
, bsi
);
3925 /* In the case of NAME <= CST and NAME being defined as
3926 NAME = (unsigned) NAME2 + CST2 we can assert NAME2 >= -CST2
3927 and NAME2 <= CST - CST2. We can do the same for NAME > CST.
3928 This catches range and anti-range tests. */
3929 if ((comp_code
== LE_EXPR
3930 || comp_code
== GT_EXPR
)
3931 && TREE_CODE (val
) == INTEGER_CST
3932 && TYPE_UNSIGNED (TREE_TYPE (val
)))
3934 gimple def_stmt
= SSA_NAME_DEF_STMT (name
);
3935 tree cst2
= NULL_TREE
, name2
= NULL_TREE
, name3
= NULL_TREE
;
3937 /* Extract CST2 from the (optional) addition. */
3938 if (is_gimple_assign (def_stmt
)
3939 && gimple_assign_rhs_code (def_stmt
) == PLUS_EXPR
)
3941 name2
= gimple_assign_rhs1 (def_stmt
);
3942 cst2
= gimple_assign_rhs2 (def_stmt
);
3943 if (TREE_CODE (name2
) == SSA_NAME
3944 && TREE_CODE (cst2
) == INTEGER_CST
)
3945 def_stmt
= SSA_NAME_DEF_STMT (name2
);
3948 /* Extract NAME2 from the (optional) sign-changing cast. */
3949 if (gimple_assign_cast_p (def_stmt
))
3951 if (CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (def_stmt
))
3952 && ! TYPE_UNSIGNED (TREE_TYPE (gimple_assign_rhs1 (def_stmt
)))
3953 && (TYPE_PRECISION (gimple_expr_type (def_stmt
))
3954 == TYPE_PRECISION (TREE_TYPE (gimple_assign_rhs1 (def_stmt
)))))
3955 name3
= gimple_assign_rhs1 (def_stmt
);
3958 /* If name3 is used later, create an ASSERT_EXPR for it. */
3959 if (name3
!= NULL_TREE
3960 && TREE_CODE (name3
) == SSA_NAME
3961 && (cst2
== NULL_TREE
3962 || TREE_CODE (cst2
) == INTEGER_CST
)
3963 && INTEGRAL_TYPE_P (TREE_TYPE (name3
))
3964 && live_on_edge (e
, name3
)
3965 && !has_single_use (name3
))
3969 /* Build an expression for the range test. */
3970 tmp
= build1 (NOP_EXPR
, TREE_TYPE (name
), name3
);
3971 if (cst2
!= NULL_TREE
)
3972 tmp
= build2 (PLUS_EXPR
, TREE_TYPE (name
), tmp
, cst2
);
3976 fprintf (dump_file
, "Adding assert for ");
3977 print_generic_expr (dump_file
, name3
, 0);
3978 fprintf (dump_file
, " from ");
3979 print_generic_expr (dump_file
, tmp
, 0);
3980 fprintf (dump_file
, "\n");
3983 register_new_assert_for (name3
, tmp
, comp_code
, val
, NULL
, e
, bsi
);
3988 /* If name2 is used later, create an ASSERT_EXPR for it. */
3989 if (name2
!= NULL_TREE
3990 && TREE_CODE (name2
) == SSA_NAME
3991 && TREE_CODE (cst2
) == INTEGER_CST
3992 && INTEGRAL_TYPE_P (TREE_TYPE (name2
))
3993 && live_on_edge (e
, name2
)
3994 && !has_single_use (name2
))
3998 /* Build an expression for the range test. */
4000 if (TREE_TYPE (name
) != TREE_TYPE (name2
))
4001 tmp
= build1 (NOP_EXPR
, TREE_TYPE (name
), tmp
);
4002 if (cst2
!= NULL_TREE
)
4003 tmp
= build2 (PLUS_EXPR
, TREE_TYPE (name
), tmp
, cst2
);
4007 fprintf (dump_file
, "Adding assert for ");
4008 print_generic_expr (dump_file
, name2
, 0);
4009 fprintf (dump_file
, " from ");
4010 print_generic_expr (dump_file
, tmp
, 0);
4011 fprintf (dump_file
, "\n");
4014 register_new_assert_for (name2
, tmp
, comp_code
, val
, NULL
, e
, bsi
);
4023 /* OP is an operand of a truth value expression which is known to have
4024 a particular value. Register any asserts for OP and for any
4025 operands in OP's defining statement.
4027 If CODE is EQ_EXPR, then we want to register OP is zero (false),
4028 if CODE is NE_EXPR, then we want to register OP is nonzero (true). */
4031 register_edge_assert_for_1 (tree op
, enum tree_code code
,
4032 edge e
, gimple_stmt_iterator bsi
)
4034 bool retval
= false;
4037 enum tree_code rhs_code
;
4039 /* We only care about SSA_NAMEs. */
4040 if (TREE_CODE (op
) != SSA_NAME
)
4043 /* We know that OP will have a zero or nonzero value. If OP is used
4044 more than once go ahead and register an assert for OP.
4046 The FOUND_IN_SUBGRAPH support is not helpful in this situation as
4047 it will always be set for OP (because OP is used in a COND_EXPR in
4049 if (!has_single_use (op
))
4051 val
= build_int_cst (TREE_TYPE (op
), 0);
4052 register_new_assert_for (op
, op
, code
, val
, NULL
, e
, bsi
);
4056 /* Now look at how OP is set. If it's set from a comparison,
4057 a truth operation or some bit operations, then we may be able
4058 to register information about the operands of that assignment. */
4059 op_def
= SSA_NAME_DEF_STMT (op
);
4060 if (gimple_code (op_def
) != GIMPLE_ASSIGN
)
4063 rhs_code
= gimple_assign_rhs_code (op_def
);
4065 if (TREE_CODE_CLASS (rhs_code
) == tcc_comparison
)
4067 bool invert
= (code
== EQ_EXPR
? true : false);
4068 tree op0
= gimple_assign_rhs1 (op_def
);
4069 tree op1
= gimple_assign_rhs2 (op_def
);
4071 if (TREE_CODE (op0
) == SSA_NAME
)
4072 retval
|= register_edge_assert_for_2 (op0
, e
, bsi
, rhs_code
, op0
, op1
,
4074 if (TREE_CODE (op1
) == SSA_NAME
)
4075 retval
|= register_edge_assert_for_2 (op1
, e
, bsi
, rhs_code
, op0
, op1
,
4078 else if ((code
== NE_EXPR
4079 && (gimple_assign_rhs_code (op_def
) == TRUTH_AND_EXPR
4080 || gimple_assign_rhs_code (op_def
) == BIT_AND_EXPR
))
4082 && (gimple_assign_rhs_code (op_def
) == TRUTH_OR_EXPR
4083 || gimple_assign_rhs_code (op_def
) == BIT_IOR_EXPR
)))
4085 /* Recurse on each operand. */
4086 retval
|= register_edge_assert_for_1 (gimple_assign_rhs1 (op_def
),
4088 retval
|= register_edge_assert_for_1 (gimple_assign_rhs2 (op_def
),
4091 else if (gimple_assign_rhs_code (op_def
) == TRUTH_NOT_EXPR
)
4093 /* Recurse, flipping CODE. */
4094 code
= invert_tree_comparison (code
, false);
4095 retval
|= register_edge_assert_for_1 (gimple_assign_rhs1 (op_def
),
4098 else if (gimple_assign_rhs_code (op_def
) == SSA_NAME
)
4100 /* Recurse through the copy. */
4101 retval
|= register_edge_assert_for_1 (gimple_assign_rhs1 (op_def
),
4104 else if (CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (op_def
)))
4106 /* Recurse through the type conversion. */
4107 retval
|= register_edge_assert_for_1 (gimple_assign_rhs1 (op_def
),
4114 /* Try to register an edge assertion for SSA name NAME on edge E for
4115 the condition COND contributing to the conditional jump pointed to by SI.
4116 Return true if an assertion for NAME could be registered. */
4119 register_edge_assert_for (tree name
, edge e
, gimple_stmt_iterator si
,
4120 enum tree_code cond_code
, tree cond_op0
,
4124 enum tree_code comp_code
;
4125 bool retval
= false;
4126 bool is_else_edge
= (e
->flags
& EDGE_FALSE_VALUE
) != 0;
4128 /* Do not attempt to infer anything in names that flow through
4130 if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (name
))
4133 if (!extract_code_and_val_from_cond_with_ops (name
, cond_code
,
4139 /* Register ASSERT_EXPRs for name. */
4140 retval
|= register_edge_assert_for_2 (name
, e
, si
, cond_code
, cond_op0
,
4141 cond_op1
, is_else_edge
);
4144 /* If COND is effectively an equality test of an SSA_NAME against
4145 the value zero or one, then we may be able to assert values
4146 for SSA_NAMEs which flow into COND. */
4148 /* In the case of NAME == 1 or NAME != 0, for TRUTH_AND_EXPR defining
4149 statement of NAME we can assert both operands of the TRUTH_AND_EXPR
4150 have nonzero value. */
4151 if (((comp_code
== EQ_EXPR
&& integer_onep (val
))
4152 || (comp_code
== NE_EXPR
&& integer_zerop (val
))))
4154 gimple def_stmt
= SSA_NAME_DEF_STMT (name
);
4156 if (is_gimple_assign (def_stmt
)
4157 && (gimple_assign_rhs_code (def_stmt
) == TRUTH_AND_EXPR
4158 || gimple_assign_rhs_code (def_stmt
) == BIT_AND_EXPR
))
4160 tree op0
= gimple_assign_rhs1 (def_stmt
);
4161 tree op1
= gimple_assign_rhs2 (def_stmt
);
4162 retval
|= register_edge_assert_for_1 (op0
, NE_EXPR
, e
, si
);
4163 retval
|= register_edge_assert_for_1 (op1
, NE_EXPR
, e
, si
);
4167 /* In the case of NAME == 0 or NAME != 1, for TRUTH_OR_EXPR defining
4168 statement of NAME we can assert both operands of the TRUTH_OR_EXPR
4170 if (((comp_code
== EQ_EXPR
&& integer_zerop (val
))
4171 || (comp_code
== NE_EXPR
&& integer_onep (val
))))
4173 gimple def_stmt
= SSA_NAME_DEF_STMT (name
);
4175 if (is_gimple_assign (def_stmt
)
4176 && (gimple_assign_rhs_code (def_stmt
) == TRUTH_OR_EXPR
4177 /* For BIT_IOR_EXPR only if NAME == 0 both operands have
4178 necessarily zero value. */
4179 || (comp_code
== EQ_EXPR
4180 && (gimple_assign_rhs_code (def_stmt
) == BIT_IOR_EXPR
))))
4182 tree op0
= gimple_assign_rhs1 (def_stmt
);
4183 tree op1
= gimple_assign_rhs2 (def_stmt
);
4184 retval
|= register_edge_assert_for_1 (op0
, EQ_EXPR
, e
, si
);
4185 retval
|= register_edge_assert_for_1 (op1
, EQ_EXPR
, e
, si
);
4193 /* Determine whether the outgoing edges of BB should receive an
4194 ASSERT_EXPR for each of the operands of BB's LAST statement.
4195 The last statement of BB must be a COND_EXPR.
4197 If any of the sub-graphs rooted at BB have an interesting use of
4198 the predicate operands, an assert location node is added to the
4199 list of assertions for the corresponding operands. */
4202 find_conditional_asserts (basic_block bb
, gimple last
)
4205 gimple_stmt_iterator bsi
;
4211 need_assert
= false;
4212 bsi
= gsi_for_stmt (last
);
4214 /* Look for uses of the operands in each of the sub-graphs
4215 rooted at BB. We need to check each of the outgoing edges
4216 separately, so that we know what kind of ASSERT_EXPR to
4218 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
4223 /* Register the necessary assertions for each operand in the
4224 conditional predicate. */
4225 FOR_EACH_SSA_TREE_OPERAND (op
, last
, iter
, SSA_OP_USE
)
4227 need_assert
|= register_edge_assert_for (op
, e
, bsi
,
4228 gimple_cond_code (last
),
4229 gimple_cond_lhs (last
),
4230 gimple_cond_rhs (last
));
4237 /* Compare two case labels sorting first by the destination label uid
4238 and then by the case value. */
4241 compare_case_labels (const void *p1
, const void *p2
)
4243 const_tree
const case1
= *(const_tree
const*)p1
;
4244 const_tree
const case2
= *(const_tree
const*)p2
;
4245 unsigned int uid1
= DECL_UID (CASE_LABEL (case1
));
4246 unsigned int uid2
= DECL_UID (CASE_LABEL (case2
));
4250 else if (uid1
== uid2
)
4252 /* Make sure the default label is first in a group. */
4253 if (!CASE_LOW (case1
))
4255 else if (!CASE_LOW (case2
))
4258 return tree_int_cst_compare (CASE_LOW (case1
), CASE_LOW (case2
));
4264 /* Determine whether the outgoing edges of BB should receive an
4265 ASSERT_EXPR for each of the operands of BB's LAST statement.
4266 The last statement of BB must be a SWITCH_EXPR.
4268 If any of the sub-graphs rooted at BB have an interesting use of
4269 the predicate operands, an assert location node is added to the
4270 list of assertions for the corresponding operands. */
4273 find_switch_asserts (basic_block bb
, gimple last
)
4276 gimple_stmt_iterator bsi
;
4280 size_t n
= gimple_switch_num_labels(last
);
4283 need_assert
= false;
4284 bsi
= gsi_for_stmt (last
);
4285 op
= gimple_switch_index (last
);
4286 if (TREE_CODE (op
) != SSA_NAME
)
4289 /* Build a vector of case labels sorted by destination label. */
4290 vec2
= make_tree_vec (n
);
4291 for (idx
= 0; idx
< n
; ++idx
)
4292 TREE_VEC_ELT (vec2
, idx
) = gimple_switch_label (last
, idx
);
4293 qsort (&TREE_VEC_ELT (vec2
, 0), n
, sizeof (tree
), compare_case_labels
);
4295 for (idx
= 0; idx
< n
; ++idx
)
4298 tree cl
= TREE_VEC_ELT (vec2
, idx
);
4300 min
= CASE_LOW (cl
);
4301 max
= CASE_HIGH (cl
);
4303 /* If there are multiple case labels with the same destination
4304 we need to combine them to a single value range for the edge. */
4306 && CASE_LABEL (cl
) == CASE_LABEL (TREE_VEC_ELT (vec2
, idx
+ 1)))
4308 /* Skip labels until the last of the group. */
4312 && CASE_LABEL (cl
) == CASE_LABEL (TREE_VEC_ELT (vec2
, idx
)));
4315 /* Pick up the maximum of the case label range. */
4316 if (CASE_HIGH (TREE_VEC_ELT (vec2
, idx
)))
4317 max
= CASE_HIGH (TREE_VEC_ELT (vec2
, idx
));
4319 max
= CASE_LOW (TREE_VEC_ELT (vec2
, idx
));
4322 /* Nothing to do if the range includes the default label until we
4323 can register anti-ranges. */
4324 if (min
== NULL_TREE
)
4327 /* Find the edge to register the assert expr on. */
4328 e
= find_edge (bb
, label_to_block (CASE_LABEL (cl
)));
4330 /* Register the necessary assertions for the operand in the
4332 need_assert
|= register_edge_assert_for (op
, e
, bsi
,
4333 max
? GE_EXPR
: EQ_EXPR
,
4335 fold_convert (TREE_TYPE (op
),
4339 need_assert
|= register_edge_assert_for (op
, e
, bsi
, LE_EXPR
,
4341 fold_convert (TREE_TYPE (op
),
4350 /* Traverse all the statements in block BB looking for statements that
4351 may generate useful assertions for the SSA names in their operand.
4352 If a statement produces a useful assertion A for name N_i, then the
4353 list of assertions already generated for N_i is scanned to
4354 determine if A is actually needed.
4356 If N_i already had the assertion A at a location dominating the
4357 current location, then nothing needs to be done. Otherwise, the
4358 new location for A is recorded instead.
4360 1- For every statement S in BB, all the variables used by S are
4361 added to bitmap FOUND_IN_SUBGRAPH.
4363 2- If statement S uses an operand N in a way that exposes a known
4364 value range for N, then if N was not already generated by an
4365 ASSERT_EXPR, create a new assert location for N. For instance,
4366 if N is a pointer and the statement dereferences it, we can
4367 assume that N is not NULL.
4369 3- COND_EXPRs are a special case of #2. We can derive range
4370 information from the predicate but need to insert different
4371 ASSERT_EXPRs for each of the sub-graphs rooted at the
4372 conditional block. If the last statement of BB is a conditional
4373 expression of the form 'X op Y', then
4375 a) Remove X and Y from the set FOUND_IN_SUBGRAPH.
4377 b) If the conditional is the only entry point to the sub-graph
4378 corresponding to the THEN_CLAUSE, recurse into it. On
4379 return, if X and/or Y are marked in FOUND_IN_SUBGRAPH, then
4380 an ASSERT_EXPR is added for the corresponding variable.
4382 c) Repeat step (b) on the ELSE_CLAUSE.
4384 d) Mark X and Y in FOUND_IN_SUBGRAPH.
4393 In this case, an assertion on the THEN clause is useful to
4394 determine that 'a' is always 9 on that edge. However, an assertion
4395 on the ELSE clause would be unnecessary.
4397 4- If BB does not end in a conditional expression, then we recurse
4398 into BB's dominator children.
4400 At the end of the recursive traversal, every SSA name will have a
4401 list of locations where ASSERT_EXPRs should be added. When a new
4402 location for name N is found, it is registered by calling
4403 register_new_assert_for. That function keeps track of all the
4404 registered assertions to prevent adding unnecessary assertions.
4405 For instance, if a pointer P_4 is dereferenced more than once in a
4406 dominator tree, only the location dominating all the dereference of
4407 P_4 will receive an ASSERT_EXPR.
4409 If this function returns true, then it means that there are names
4410 for which we need to generate ASSERT_EXPRs. Those assertions are
4411 inserted by process_assert_insertions. */
4414 find_assert_locations_1 (basic_block bb
, sbitmap live
)
4416 gimple_stmt_iterator si
;
4421 need_assert
= false;
4422 last
= last_stmt (bb
);
4424 /* If BB's last statement is a conditional statement involving integer
4425 operands, determine if we need to add ASSERT_EXPRs. */
4427 && gimple_code (last
) == GIMPLE_COND
4428 && !fp_predicate (last
)
4429 && !ZERO_SSA_OPERANDS (last
, SSA_OP_USE
))
4430 need_assert
|= find_conditional_asserts (bb
, last
);
4432 /* If BB's last statement is a switch statement involving integer
4433 operands, determine if we need to add ASSERT_EXPRs. */
4435 && gimple_code (last
) == GIMPLE_SWITCH
4436 && !ZERO_SSA_OPERANDS (last
, SSA_OP_USE
))
4437 need_assert
|= find_switch_asserts (bb
, last
);
4439 /* Traverse all the statements in BB marking used names and looking
4440 for statements that may infer assertions for their used operands. */
4441 for (si
= gsi_start_bb (bb
); !gsi_end_p (si
); gsi_next (&si
))
4447 stmt
= gsi_stmt (si
);
4449 /* See if we can derive an assertion for any of STMT's operands. */
4450 FOR_EACH_SSA_TREE_OPERAND (op
, stmt
, i
, SSA_OP_USE
)
4453 enum tree_code comp_code
;
4455 /* Mark OP in our live bitmap. */
4456 SET_BIT (live
, SSA_NAME_VERSION (op
));
4458 /* If OP is used in such a way that we can infer a value
4459 range for it, and we don't find a previous assertion for
4460 it, create a new assertion location node for OP. */
4461 if (infer_value_range (stmt
, op
, &comp_code
, &value
))
4463 /* If we are able to infer a nonzero value range for OP,
4464 then walk backwards through the use-def chain to see if OP
4465 was set via a typecast.
4467 If so, then we can also infer a nonzero value range
4468 for the operand of the NOP_EXPR. */
4469 if (comp_code
== NE_EXPR
&& integer_zerop (value
))
4472 gimple def_stmt
= SSA_NAME_DEF_STMT (t
);
4474 while (is_gimple_assign (def_stmt
)
4475 && gimple_assign_rhs_code (def_stmt
) == NOP_EXPR
4477 (gimple_assign_rhs1 (def_stmt
)) == SSA_NAME
4479 (TREE_TYPE (gimple_assign_rhs1 (def_stmt
))))
4481 t
= gimple_assign_rhs1 (def_stmt
);
4482 def_stmt
= SSA_NAME_DEF_STMT (t
);
4484 /* Note we want to register the assert for the
4485 operand of the NOP_EXPR after SI, not after the
4487 if (! has_single_use (t
))
4489 register_new_assert_for (t
, t
, comp_code
, value
,
4496 /* If OP is used only once, namely in this STMT, don't
4497 bother creating an ASSERT_EXPR for it. Such an
4498 ASSERT_EXPR would do nothing but increase compile time. */
4499 if (!has_single_use (op
))
4501 register_new_assert_for (op
, op
, comp_code
, value
,
4509 /* Traverse all PHI nodes in BB marking used operands. */
4510 for (si
= gsi_start_phis (bb
); !gsi_end_p(si
); gsi_next (&si
))
4512 use_operand_p arg_p
;
4514 phi
= gsi_stmt (si
);
4516 FOR_EACH_PHI_ARG (arg_p
, phi
, i
, SSA_OP_USE
)
4518 tree arg
= USE_FROM_PTR (arg_p
);
4519 if (TREE_CODE (arg
) == SSA_NAME
)
4520 SET_BIT (live
, SSA_NAME_VERSION (arg
));
4527 /* Do an RPO walk over the function computing SSA name liveness
4528 on-the-fly and deciding on assert expressions to insert.
4529 Returns true if there are assert expressions to be inserted. */
4532 find_assert_locations (void)
4534 int *rpo
= XCNEWVEC (int, last_basic_block
+ NUM_FIXED_BLOCKS
);
4535 int *bb_rpo
= XCNEWVEC (int, last_basic_block
+ NUM_FIXED_BLOCKS
);
4536 int *last_rpo
= XCNEWVEC (int, last_basic_block
+ NUM_FIXED_BLOCKS
);
4540 live
= XCNEWVEC (sbitmap
, last_basic_block
+ NUM_FIXED_BLOCKS
);
4541 rpo_cnt
= pre_and_rev_post_order_compute (NULL
, rpo
, false);
4542 for (i
= 0; i
< rpo_cnt
; ++i
)
4545 need_asserts
= false;
4546 for (i
= rpo_cnt
-1; i
>= 0; --i
)
4548 basic_block bb
= BASIC_BLOCK (rpo
[i
]);
4554 live
[rpo
[i
]] = sbitmap_alloc (num_ssa_names
);
4555 sbitmap_zero (live
[rpo
[i
]]);
4558 /* Process BB and update the live information with uses in
4560 need_asserts
|= find_assert_locations_1 (bb
, live
[rpo
[i
]]);
4562 /* Merge liveness into the predecessor blocks and free it. */
4563 if (!sbitmap_empty_p (live
[rpo
[i
]]))
4566 FOR_EACH_EDGE (e
, ei
, bb
->preds
)
4568 int pred
= e
->src
->index
;
4569 if (e
->flags
& EDGE_DFS_BACK
)
4574 live
[pred
] = sbitmap_alloc (num_ssa_names
);
4575 sbitmap_zero (live
[pred
]);
4577 sbitmap_a_or_b (live
[pred
], live
[pred
], live
[rpo
[i
]]);
4579 if (bb_rpo
[pred
] < pred_rpo
)
4580 pred_rpo
= bb_rpo
[pred
];
4583 /* Record the RPO number of the last visited block that needs
4584 live information from this block. */
4585 last_rpo
[rpo
[i
]] = pred_rpo
;
4589 sbitmap_free (live
[rpo
[i
]]);
4590 live
[rpo
[i
]] = NULL
;
4593 /* We can free all successors live bitmaps if all their
4594 predecessors have been visited already. */
4595 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
4596 if (last_rpo
[e
->dest
->index
] == i
4597 && live
[e
->dest
->index
])
4599 sbitmap_free (live
[e
->dest
->index
]);
4600 live
[e
->dest
->index
] = NULL
;
4605 XDELETEVEC (bb_rpo
);
4606 XDELETEVEC (last_rpo
);
4607 for (i
= 0; i
< last_basic_block
+ NUM_FIXED_BLOCKS
; ++i
)
4609 sbitmap_free (live
[i
]);
4612 return need_asserts
;
4615 /* Create an ASSERT_EXPR for NAME and insert it in the location
4616 indicated by LOC. Return true if we made any edge insertions. */
4619 process_assert_insertions_for (tree name
, assert_locus_t loc
)
4621 /* Build the comparison expression NAME_i COMP_CODE VAL. */
4628 cond
= build2 (loc
->comp_code
, boolean_type_node
, loc
->expr
, loc
->val
);
4629 assert_stmt
= build_assert_expr_for (cond
, name
);
4632 /* We have been asked to insert the assertion on an edge. This
4633 is used only by COND_EXPR and SWITCH_EXPR assertions. */
4634 #if defined ENABLE_CHECKING
4635 gcc_assert (gimple_code (gsi_stmt (loc
->si
)) == GIMPLE_COND
4636 || gimple_code (gsi_stmt (loc
->si
)) == GIMPLE_SWITCH
);
4639 gsi_insert_on_edge (loc
->e
, assert_stmt
);
4643 /* Otherwise, we can insert right after LOC->SI iff the
4644 statement must not be the last statement in the block. */
4645 stmt
= gsi_stmt (loc
->si
);
4646 if (!stmt_ends_bb_p (stmt
))
4648 gsi_insert_after (&loc
->si
, assert_stmt
, GSI_SAME_STMT
);
4652 /* If STMT must be the last statement in BB, we can only insert new
4653 assertions on the non-abnormal edge out of BB. Note that since
4654 STMT is not control flow, there may only be one non-abnormal edge
4656 FOR_EACH_EDGE (e
, ei
, loc
->bb
->succs
)
4657 if (!(e
->flags
& EDGE_ABNORMAL
))
4659 gsi_insert_on_edge (e
, assert_stmt
);
4667 /* Process all the insertions registered for every name N_i registered
4668 in NEED_ASSERT_FOR. The list of assertions to be inserted are
4669 found in ASSERTS_FOR[i]. */
4672 process_assert_insertions (void)
4676 bool update_edges_p
= false;
4677 int num_asserts
= 0;
4679 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
4680 dump_all_asserts (dump_file
);
4682 EXECUTE_IF_SET_IN_BITMAP (need_assert_for
, 0, i
, bi
)
4684 assert_locus_t loc
= asserts_for
[i
];
4689 assert_locus_t next
= loc
->next
;
4690 update_edges_p
|= process_assert_insertions_for (ssa_name (i
), loc
);
4698 gsi_commit_edge_inserts ();
4700 statistics_counter_event (cfun
, "Number of ASSERT_EXPR expressions inserted",
4705 /* Traverse the flowgraph looking for conditional jumps to insert range
4706 expressions. These range expressions are meant to provide information
4707 to optimizations that need to reason in terms of value ranges. They
4708 will not be expanded into RTL. For instance, given:
4717 this pass will transform the code into:
4723 x = ASSERT_EXPR <x, x < y>
4728 y = ASSERT_EXPR <y, x <= y>
4732 The idea is that once copy and constant propagation have run, other
4733 optimizations will be able to determine what ranges of values can 'x'
4734 take in different paths of the code, simply by checking the reaching
4735 definition of 'x'. */
4738 insert_range_assertions (void)
4740 need_assert_for
= BITMAP_ALLOC (NULL
);
4741 asserts_for
= XCNEWVEC (assert_locus_t
, num_ssa_names
);
4743 calculate_dominance_info (CDI_DOMINATORS
);
4745 if (find_assert_locations ())
4747 process_assert_insertions ();
4748 update_ssa (TODO_update_ssa_no_phi
);
4751 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
4753 fprintf (dump_file
, "\nSSA form after inserting ASSERT_EXPRs\n");
4754 dump_function_to_file (current_function_decl
, dump_file
, dump_flags
);
4758 BITMAP_FREE (need_assert_for
);
4761 /* Checks one ARRAY_REF in REF, located at LOCUS. Ignores flexible arrays
4762 and "struct" hacks. If VRP can determine that the
4763 array subscript is a constant, check if it is outside valid
4764 range. If the array subscript is a RANGE, warn if it is
4765 non-overlapping with valid range.
4766 IGNORE_OFF_BY_ONE is true if the ARRAY_REF is inside a ADDR_EXPR. */
4769 check_array_ref (tree ref
, const location_t
*location
, bool ignore_off_by_one
)
4771 value_range_t
* vr
= NULL
;
4772 tree low_sub
, up_sub
;
4773 tree low_bound
, up_bound
= array_ref_up_bound (ref
);
4775 low_sub
= up_sub
= TREE_OPERAND (ref
, 1);
4777 if (!up_bound
|| TREE_NO_WARNING (ref
)
4778 || TREE_CODE (up_bound
) != INTEGER_CST
4779 /* Can not check flexible arrays. */
4780 || (TYPE_SIZE (TREE_TYPE (ref
)) == NULL_TREE
4781 && TYPE_DOMAIN (TREE_TYPE (ref
)) != NULL_TREE
4782 && TYPE_MAX_VALUE (TYPE_DOMAIN (TREE_TYPE (ref
))) == NULL_TREE
)
4783 /* Accesses after the end of arrays of size 0 (gcc
4784 extension) and 1 are likely intentional ("struct
4786 || compare_tree_int (up_bound
, 1) <= 0)
4789 low_bound
= array_ref_low_bound (ref
);
4791 if (TREE_CODE (low_sub
) == SSA_NAME
)
4793 vr
= get_value_range (low_sub
);
4794 if (vr
->type
== VR_RANGE
|| vr
->type
== VR_ANTI_RANGE
)
4796 low_sub
= vr
->type
== VR_RANGE
? vr
->max
: vr
->min
;
4797 up_sub
= vr
->type
== VR_RANGE
? vr
->min
: vr
->max
;
4801 if (vr
&& vr
->type
== VR_ANTI_RANGE
)
4803 if (TREE_CODE (up_sub
) == INTEGER_CST
4804 && tree_int_cst_lt (up_bound
, up_sub
)
4805 && TREE_CODE (low_sub
) == INTEGER_CST
4806 && tree_int_cst_lt (low_sub
, low_bound
))
4808 warning (OPT_Warray_bounds
,
4809 "%Harray subscript is outside array bounds", location
);
4810 TREE_NO_WARNING (ref
) = 1;
4813 else if (TREE_CODE (up_sub
) == INTEGER_CST
4814 && tree_int_cst_lt (up_bound
, up_sub
)
4815 && !tree_int_cst_equal (up_bound
, up_sub
)
4816 && (!ignore_off_by_one
4817 || !tree_int_cst_equal (int_const_binop (PLUS_EXPR
,
4823 warning (OPT_Warray_bounds
, "%Harray subscript is above array bounds",
4825 TREE_NO_WARNING (ref
) = 1;
4827 else if (TREE_CODE (low_sub
) == INTEGER_CST
4828 && tree_int_cst_lt (low_sub
, low_bound
))
4830 warning (OPT_Warray_bounds
, "%Harray subscript is below array bounds",
4832 TREE_NO_WARNING (ref
) = 1;
4836 /* Searches if the expr T, located at LOCATION computes
4837 address of an ARRAY_REF, and call check_array_ref on it. */
4840 search_for_addr_array(tree t
, const location_t
*location
)
4842 while (TREE_CODE (t
) == SSA_NAME
)
4844 gimple g
= SSA_NAME_DEF_STMT (t
);
4846 if (gimple_code (g
) != GIMPLE_ASSIGN
)
4849 if (get_gimple_rhs_class (gimple_assign_rhs_code (g
)) !=
4853 t
= gimple_assign_rhs1 (g
);
4857 /* We are only interested in addresses of ARRAY_REF's. */
4858 if (TREE_CODE (t
) != ADDR_EXPR
)
4861 /* Check each ARRAY_REFs in the reference chain. */
4864 if (TREE_CODE (t
) == ARRAY_REF
)
4865 check_array_ref (t
, location
, true /*ignore_off_by_one*/);
4867 t
= TREE_OPERAND(t
,0);
4869 while (handled_component_p (t
));
4872 /* walk_tree() callback that checks if *TP is
4873 an ARRAY_REF inside an ADDR_EXPR (in which an array
4874 subscript one outside the valid range is allowed). Call
4875 check_array_ref for each ARRAY_REF found. The location is
4879 check_array_bounds (tree
*tp
, int *walk_subtree
, void *data
)
4882 struct walk_stmt_info
*wi
= (struct walk_stmt_info
*) data
;
4883 const location_t
*location
= (const location_t
*) wi
->info
;
4885 *walk_subtree
= TRUE
;
4887 if (TREE_CODE (t
) == ARRAY_REF
)
4888 check_array_ref (t
, location
, false /*ignore_off_by_one*/);
4890 if (TREE_CODE (t
) == INDIRECT_REF
4891 || (TREE_CODE (t
) == RETURN_EXPR
&& TREE_OPERAND (t
, 0)))
4892 search_for_addr_array (TREE_OPERAND (t
, 0), location
);
4894 if (TREE_CODE (t
) == ADDR_EXPR
)
4895 *walk_subtree
= FALSE
;
4900 /* Walk over all statements of all reachable BBs and call check_array_bounds
4904 check_all_array_refs (void)
4907 gimple_stmt_iterator si
;
4911 /* Skip bb's that are clearly unreachable. */
4912 if (single_pred_p (bb
))
4914 basic_block pred_bb
= EDGE_PRED (bb
, 0)->src
;
4917 if (!gsi_end_p (gsi_last_bb (pred_bb
)))
4918 ls
= gsi_stmt (gsi_last_bb (pred_bb
));
4920 if (ls
&& gimple_code (ls
) == GIMPLE_COND
4921 && ((gimple_cond_false_p (ls
)
4922 && (EDGE_PRED (bb
, 0)->flags
& EDGE_TRUE_VALUE
))
4923 || (gimple_cond_true_p (ls
)
4924 && (EDGE_PRED (bb
, 0)->flags
& EDGE_FALSE_VALUE
))))
4927 for (si
= gsi_start_bb (bb
); !gsi_end_p (si
); gsi_next (&si
))
4929 gimple stmt
= gsi_stmt (si
);
4930 const location_t
*location
= gimple_location_ptr (stmt
);
4931 struct walk_stmt_info wi
;
4932 if (!gimple_has_location (stmt
))
4935 if (is_gimple_call (stmt
))
4938 size_t n
= gimple_call_num_args (stmt
);
4939 for (i
= 0; i
< n
; i
++)
4941 tree arg
= gimple_call_arg (stmt
, i
);
4942 search_for_addr_array (arg
, location
);
4947 memset (&wi
, 0, sizeof (wi
));
4948 wi
.info
= CONST_CAST (void *, (const void *) location
);
4950 walk_gimple_op (gsi_stmt (si
),
4958 /* Convert range assertion expressions into the implied copies and
4959 copy propagate away the copies. Doing the trivial copy propagation
4960 here avoids the need to run the full copy propagation pass after
4963 FIXME, this will eventually lead to copy propagation removing the
4964 names that had useful range information attached to them. For
4965 instance, if we had the assertion N_i = ASSERT_EXPR <N_j, N_j > 3>,
4966 then N_i will have the range [3, +INF].
4968 However, by converting the assertion into the implied copy
4969 operation N_i = N_j, we will then copy-propagate N_j into the uses
4970 of N_i and lose the range information. We may want to hold on to
4971 ASSERT_EXPRs a little while longer as the ranges could be used in
4972 things like jump threading.
4974 The problem with keeping ASSERT_EXPRs around is that passes after
4975 VRP need to handle them appropriately.
4977 Another approach would be to make the range information a first
4978 class property of the SSA_NAME so that it can be queried from
4979 any pass. This is made somewhat more complex by the need for
4980 multiple ranges to be associated with one SSA_NAME. */
4983 remove_range_assertions (void)
4986 gimple_stmt_iterator si
;
4988 /* Note that the BSI iterator bump happens at the bottom of the
4989 loop and no bump is necessary if we're removing the statement
4990 referenced by the current BSI. */
4992 for (si
= gsi_start_bb (bb
); !gsi_end_p (si
);)
4994 gimple stmt
= gsi_stmt (si
);
4997 if (is_gimple_assign (stmt
)
4998 && gimple_assign_rhs_code (stmt
) == ASSERT_EXPR
)
5000 tree rhs
= gimple_assign_rhs1 (stmt
);
5002 tree cond
= fold (ASSERT_EXPR_COND (rhs
));
5003 use_operand_p use_p
;
5004 imm_use_iterator iter
;
5006 gcc_assert (cond
!= boolean_false_node
);
5008 /* Propagate the RHS into every use of the LHS. */
5009 var
= ASSERT_EXPR_VAR (rhs
);
5010 FOR_EACH_IMM_USE_STMT (use_stmt
, iter
,
5011 gimple_assign_lhs (stmt
))
5012 FOR_EACH_IMM_USE_ON_STMT (use_p
, iter
)
5014 SET_USE (use_p
, var
);
5015 gcc_assert (TREE_CODE (var
) == SSA_NAME
);
5018 /* And finally, remove the copy, it is not needed. */
5019 gsi_remove (&si
, true);
5020 release_defs (stmt
);
5028 /* Return true if STMT is interesting for VRP. */
5031 stmt_interesting_for_vrp (gimple stmt
)
5033 if (gimple_code (stmt
) == GIMPLE_PHI
5034 && is_gimple_reg (gimple_phi_result (stmt
))
5035 && (INTEGRAL_TYPE_P (TREE_TYPE (gimple_phi_result (stmt
)))
5036 || POINTER_TYPE_P (TREE_TYPE (gimple_phi_result (stmt
)))))
5038 else if (is_gimple_assign (stmt
) || is_gimple_call (stmt
))
5040 tree lhs
= gimple_get_lhs (stmt
);
5042 /* In general, assignments with virtual operands are not useful
5043 for deriving ranges, with the obvious exception of calls to
5044 builtin functions. */
5045 if (lhs
&& TREE_CODE (lhs
) == SSA_NAME
5046 && (INTEGRAL_TYPE_P (TREE_TYPE (lhs
))
5047 || POINTER_TYPE_P (TREE_TYPE (lhs
)))
5048 && ((is_gimple_call (stmt
)
5049 && gimple_call_fndecl (stmt
) != NULL_TREE
5050 && DECL_IS_BUILTIN (gimple_call_fndecl (stmt
)))
5051 || ZERO_SSA_OPERANDS (stmt
, SSA_OP_ALL_VIRTUALS
)))
5054 else if (gimple_code (stmt
) == GIMPLE_COND
5055 || gimple_code (stmt
) == GIMPLE_SWITCH
)
5062 /* Initialize local data structures for VRP. */
5065 vrp_initialize (void)
5069 vr_value
= XCNEWVEC (value_range_t
*, num_ssa_names
);
5070 vr_phi_edge_counts
= XCNEWVEC (int, num_ssa_names
);
5074 gimple_stmt_iterator si
;
5076 for (si
= gsi_start_phis (bb
); !gsi_end_p (si
); gsi_next (&si
))
5078 gimple phi
= gsi_stmt (si
);
5079 if (!stmt_interesting_for_vrp (phi
))
5081 tree lhs
= PHI_RESULT (phi
);
5082 set_value_range_to_varying (get_value_range (lhs
));
5083 prop_set_simulate_again (phi
, false);
5086 prop_set_simulate_again (phi
, true);
5089 for (si
= gsi_start_bb (bb
); !gsi_end_p (si
); gsi_next (&si
))
5091 gimple stmt
= gsi_stmt (si
);
5093 if (!stmt_interesting_for_vrp (stmt
))
5097 FOR_EACH_SSA_TREE_OPERAND (def
, stmt
, i
, SSA_OP_DEF
)
5098 set_value_range_to_varying (get_value_range (def
));
5099 prop_set_simulate_again (stmt
, false);
5103 prop_set_simulate_again (stmt
, true);
5110 /* Visit assignment STMT. If it produces an interesting range, record
5111 the SSA name in *OUTPUT_P. */
5113 static enum ssa_prop_result
5114 vrp_visit_assignment_or_call (gimple stmt
, tree
*output_p
)
5118 enum gimple_code code
= gimple_code (stmt
);
5119 lhs
= gimple_get_lhs (stmt
);
5121 /* We only keep track of ranges in integral and pointer types. */
5122 if (TREE_CODE (lhs
) == SSA_NAME
5123 && ((INTEGRAL_TYPE_P (TREE_TYPE (lhs
))
5124 /* It is valid to have NULL MIN/MAX values on a type. See
5125 build_range_type. */
5126 && TYPE_MIN_VALUE (TREE_TYPE (lhs
))
5127 && TYPE_MAX_VALUE (TREE_TYPE (lhs
)))
5128 || POINTER_TYPE_P (TREE_TYPE (lhs
))))
5131 value_range_t new_vr
= { VR_UNDEFINED
, NULL_TREE
, NULL_TREE
, NULL
};
5133 if (code
== GIMPLE_CALL
)
5134 extract_range_basic (&new_vr
, stmt
);
5136 extract_range_from_assignment (&new_vr
, stmt
);
5138 /* If STMT is inside a loop, we may be able to know something
5139 else about the range of LHS by examining scalar evolution
5141 if (current_loops
&& (l
= loop_containing_stmt (stmt
)))
5142 adjust_range_with_scev (&new_vr
, l
, stmt
, lhs
);
5144 if (update_value_range (lhs
, &new_vr
))
5148 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
5150 fprintf (dump_file
, "Found new range for ");
5151 print_generic_expr (dump_file
, lhs
, 0);
5152 fprintf (dump_file
, ": ");
5153 dump_value_range (dump_file
, &new_vr
);
5154 fprintf (dump_file
, "\n\n");
5157 if (new_vr
.type
== VR_VARYING
)
5158 return SSA_PROP_VARYING
;
5160 return SSA_PROP_INTERESTING
;
5163 return SSA_PROP_NOT_INTERESTING
;
5166 /* Every other statement produces no useful ranges. */
5167 FOR_EACH_SSA_TREE_OPERAND (def
, stmt
, iter
, SSA_OP_DEF
)
5168 set_value_range_to_varying (get_value_range (def
));
5170 return SSA_PROP_VARYING
;
5173 /* Helper that gets the value range of the SSA_NAME with version I
5174 or a symbolic range containing the SSA_NAME only if the value range
5175 is varying or undefined. */
5177 static inline value_range_t
5178 get_vr_for_comparison (int i
)
5180 value_range_t vr
= *(vr_value
[i
]);
5182 /* If name N_i does not have a valid range, use N_i as its own
5183 range. This allows us to compare against names that may
5184 have N_i in their ranges. */
5185 if (vr
.type
== VR_VARYING
|| vr
.type
== VR_UNDEFINED
)
5188 vr
.min
= ssa_name (i
);
5189 vr
.max
= ssa_name (i
);
5195 /* Compare all the value ranges for names equivalent to VAR with VAL
5196 using comparison code COMP. Return the same value returned by
5197 compare_range_with_value, including the setting of
5198 *STRICT_OVERFLOW_P. */
5201 compare_name_with_value (enum tree_code comp
, tree var
, tree val
,
5202 bool *strict_overflow_p
)
5208 int used_strict_overflow
;
5210 value_range_t equiv_vr
;
5212 /* Get the set of equivalences for VAR. */
5213 e
= get_value_range (var
)->equiv
;
5215 /* Start at -1. Set it to 0 if we do a comparison without relying
5216 on overflow, or 1 if all comparisons rely on overflow. */
5217 used_strict_overflow
= -1;
5219 /* Compare vars' value range with val. */
5220 equiv_vr
= get_vr_for_comparison (SSA_NAME_VERSION (var
));
5222 retval
= compare_range_with_value (comp
, &equiv_vr
, val
, &sop
);
5224 used_strict_overflow
= sop
? 1 : 0;
5226 /* If the equiv set is empty we have done all work we need to do. */
5230 && used_strict_overflow
> 0)
5231 *strict_overflow_p
= true;
5235 EXECUTE_IF_SET_IN_BITMAP (e
, 0, i
, bi
)
5237 equiv_vr
= get_vr_for_comparison (i
);
5239 t
= compare_range_with_value (comp
, &equiv_vr
, val
, &sop
);
5242 /* If we get different answers from different members
5243 of the equivalence set this check must be in a dead
5244 code region. Folding it to a trap representation
5245 would be correct here. For now just return don't-know. */
5255 used_strict_overflow
= 0;
5256 else if (used_strict_overflow
< 0)
5257 used_strict_overflow
= 1;
5262 && used_strict_overflow
> 0)
5263 *strict_overflow_p
= true;
5269 /* Given a comparison code COMP and names N1 and N2, compare all the
5270 ranges equivalent to N1 against all the ranges equivalent to N2
5271 to determine the value of N1 COMP N2. Return the same value
5272 returned by compare_ranges. Set *STRICT_OVERFLOW_P to indicate
5273 whether we relied on an overflow infinity in the comparison. */
5277 compare_names (enum tree_code comp
, tree n1
, tree n2
,
5278 bool *strict_overflow_p
)
5282 bitmap_iterator bi1
, bi2
;
5284 int used_strict_overflow
;
5285 static bitmap_obstack
*s_obstack
= NULL
;
5286 static bitmap s_e1
= NULL
, s_e2
= NULL
;
5288 /* Compare the ranges of every name equivalent to N1 against the
5289 ranges of every name equivalent to N2. */
5290 e1
= get_value_range (n1
)->equiv
;
5291 e2
= get_value_range (n2
)->equiv
;
5293 /* Use the fake bitmaps if e1 or e2 are not available. */
5294 if (s_obstack
== NULL
)
5296 s_obstack
= XNEW (bitmap_obstack
);
5297 bitmap_obstack_initialize (s_obstack
);
5298 s_e1
= BITMAP_ALLOC (s_obstack
);
5299 s_e2
= BITMAP_ALLOC (s_obstack
);
5306 /* Add N1 and N2 to their own set of equivalences to avoid
5307 duplicating the body of the loop just to check N1 and N2
5309 bitmap_set_bit (e1
, SSA_NAME_VERSION (n1
));
5310 bitmap_set_bit (e2
, SSA_NAME_VERSION (n2
));
5312 /* If the equivalence sets have a common intersection, then the two
5313 names can be compared without checking their ranges. */
5314 if (bitmap_intersect_p (e1
, e2
))
5316 bitmap_clear_bit (e1
, SSA_NAME_VERSION (n1
));
5317 bitmap_clear_bit (e2
, SSA_NAME_VERSION (n2
));
5319 return (comp
== EQ_EXPR
|| comp
== GE_EXPR
|| comp
== LE_EXPR
)
5321 : boolean_false_node
;
5324 /* Start at -1. Set it to 0 if we do a comparison without relying
5325 on overflow, or 1 if all comparisons rely on overflow. */
5326 used_strict_overflow
= -1;
5328 /* Otherwise, compare all the equivalent ranges. First, add N1 and
5329 N2 to their own set of equivalences to avoid duplicating the body
5330 of the loop just to check N1 and N2 ranges. */
5331 EXECUTE_IF_SET_IN_BITMAP (e1
, 0, i1
, bi1
)
5333 value_range_t vr1
= get_vr_for_comparison (i1
);
5335 t
= retval
= NULL_TREE
;
5336 EXECUTE_IF_SET_IN_BITMAP (e2
, 0, i2
, bi2
)
5340 value_range_t vr2
= get_vr_for_comparison (i2
);
5342 t
= compare_ranges (comp
, &vr1
, &vr2
, &sop
);
5345 /* If we get different answers from different members
5346 of the equivalence set this check must be in a dead
5347 code region. Folding it to a trap representation
5348 would be correct here. For now just return don't-know. */
5352 bitmap_clear_bit (e1
, SSA_NAME_VERSION (n1
));
5353 bitmap_clear_bit (e2
, SSA_NAME_VERSION (n2
));
5359 used_strict_overflow
= 0;
5360 else if (used_strict_overflow
< 0)
5361 used_strict_overflow
= 1;
5367 bitmap_clear_bit (e1
, SSA_NAME_VERSION (n1
));
5368 bitmap_clear_bit (e2
, SSA_NAME_VERSION (n2
));
5369 if (used_strict_overflow
> 0)
5370 *strict_overflow_p
= true;
5375 /* None of the equivalent ranges are useful in computing this
5377 bitmap_clear_bit (e1
, SSA_NAME_VERSION (n1
));
5378 bitmap_clear_bit (e2
, SSA_NAME_VERSION (n2
));
5382 /* Helper function for vrp_evaluate_conditional_warnv. */
5385 vrp_evaluate_conditional_warnv_with_ops (enum tree_code code
, tree op0
,
5386 tree op1
, bool use_equiv_p
,
5387 bool *strict_overflow_p
)
5389 /* We only deal with integral and pointer types. */
5390 if (!INTEGRAL_TYPE_P (TREE_TYPE (op0
))
5391 && !POINTER_TYPE_P (TREE_TYPE (op0
)))
5396 if (TREE_CODE (op0
) == SSA_NAME
&& TREE_CODE (op1
) == SSA_NAME
)
5397 return compare_names (code
, op0
, op1
, strict_overflow_p
);
5398 else if (TREE_CODE (op0
) == SSA_NAME
)
5399 return compare_name_with_value (code
, op0
, op1
, strict_overflow_p
);
5400 else if (TREE_CODE (op1
) == SSA_NAME
)
5401 return (compare_name_with_value
5402 (swap_tree_comparison (code
), op1
, op0
, strict_overflow_p
));
5406 value_range_t
*vr0
, *vr1
;
5408 vr0
= (TREE_CODE (op0
) == SSA_NAME
) ? get_value_range (op0
) : NULL
;
5409 vr1
= (TREE_CODE (op1
) == SSA_NAME
) ? get_value_range (op1
) : NULL
;
5412 return compare_ranges (code
, vr0
, vr1
, strict_overflow_p
);
5413 else if (vr0
&& vr1
== NULL
)
5414 return compare_range_with_value (code
, vr0
, op1
, strict_overflow_p
);
5415 else if (vr0
== NULL
&& vr1
)
5416 return (compare_range_with_value
5417 (swap_tree_comparison (code
), vr1
, op0
, strict_overflow_p
));
5422 /* Given (CODE OP0 OP1) within STMT, try to simplify it based on value range
5423 information. Return NULL if the conditional can not be evaluated.
5424 The ranges of all the names equivalent with the operands in COND
5425 will be used when trying to compute the value. If the result is
5426 based on undefined signed overflow, issue a warning if
5430 vrp_evaluate_conditional (enum tree_code code
, tree op0
, tree op1
, gimple stmt
)
5436 ret
= vrp_evaluate_conditional_warnv_with_ops (code
, op0
, op1
, true, &sop
);
5440 enum warn_strict_overflow_code wc
;
5441 const char* warnmsg
;
5443 if (is_gimple_min_invariant (ret
))
5445 wc
= WARN_STRICT_OVERFLOW_CONDITIONAL
;
5446 warnmsg
= G_("assuming signed overflow does not occur when "
5447 "simplifying conditional to constant");
5451 wc
= WARN_STRICT_OVERFLOW_COMPARISON
;
5452 warnmsg
= G_("assuming signed overflow does not occur when "
5453 "simplifying conditional");
5456 if (issue_strict_overflow_warning (wc
))
5458 location_t location
;
5460 if (!gimple_has_location (stmt
))
5461 location
= input_location
;
5463 location
= gimple_location (stmt
);
5464 warning (OPT_Wstrict_overflow
, "%H%s", &location
, warnmsg
);
5468 if (warn_type_limits
5470 && TREE_CODE_CLASS (code
) == tcc_comparison
5471 && TREE_CODE (op0
) == SSA_NAME
)
5473 /* If the comparison is being folded and the operand on the LHS
5474 is being compared against a constant value that is outside of
5475 the natural range of OP0's type, then the predicate will
5476 always fold regardless of the value of OP0. If -Wtype-limits
5477 was specified, emit a warning. */
5478 const char *warnmsg
= NULL
;
5479 tree type
= TREE_TYPE (op0
);
5480 value_range_t
*vr0
= get_value_range (op0
);
5482 if (vr0
->type
!= VR_VARYING
5483 && INTEGRAL_TYPE_P (type
)
5484 && vrp_val_is_min (vr0
->min
)
5485 && vrp_val_is_max (vr0
->max
)
5486 && is_gimple_min_invariant (op1
))
5488 if (integer_zerop (ret
))
5489 warnmsg
= G_("comparison always false due to limited range of "
5492 warnmsg
= G_("comparison always true due to limited range of "
5498 location_t location
;
5500 if (!gimple_has_location (stmt
))
5501 location
= input_location
;
5503 location
= gimple_location (stmt
);
5505 warning (OPT_Wtype_limits
, "%H%s", &location
, warnmsg
);
5513 /* Visit conditional statement STMT. If we can determine which edge
5514 will be taken out of STMT's basic block, record it in
5515 *TAKEN_EDGE_P and return SSA_PROP_INTERESTING. Otherwise, return
5516 SSA_PROP_VARYING. */
5518 static enum ssa_prop_result
5519 vrp_visit_cond_stmt (gimple stmt
, edge
*taken_edge_p
)
5524 *taken_edge_p
= NULL
;
5526 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
5531 fprintf (dump_file
, "\nVisiting conditional with predicate: ");
5532 print_gimple_stmt (dump_file
, stmt
, 0, 0);
5533 fprintf (dump_file
, "\nWith known ranges\n");
5535 FOR_EACH_SSA_TREE_OPERAND (use
, stmt
, i
, SSA_OP_USE
)
5537 fprintf (dump_file
, "\t");
5538 print_generic_expr (dump_file
, use
, 0);
5539 fprintf (dump_file
, ": ");
5540 dump_value_range (dump_file
, vr_value
[SSA_NAME_VERSION (use
)]);
5543 fprintf (dump_file
, "\n");
5546 /* Compute the value of the predicate COND by checking the known
5547 ranges of each of its operands.
5549 Note that we cannot evaluate all the equivalent ranges here
5550 because those ranges may not yet be final and with the current
5551 propagation strategy, we cannot determine when the value ranges
5552 of the names in the equivalence set have changed.
5554 For instance, given the following code fragment
5558 i_14 = ASSERT_EXPR <i_5, i_5 != 0>
5562 Assume that on the first visit to i_14, i_5 has the temporary
5563 range [8, 8] because the second argument to the PHI function is
5564 not yet executable. We derive the range ~[0, 0] for i_14 and the
5565 equivalence set { i_5 }. So, when we visit 'if (i_14 == 1)' for
5566 the first time, since i_14 is equivalent to the range [8, 8], we
5567 determine that the predicate is always false.
5569 On the next round of propagation, i_13 is determined to be
5570 VARYING, which causes i_5 to drop down to VARYING. So, another
5571 visit to i_14 is scheduled. In this second visit, we compute the
5572 exact same range and equivalence set for i_14, namely ~[0, 0] and
5573 { i_5 }. But we did not have the previous range for i_5
5574 registered, so vrp_visit_assignment thinks that the range for
5575 i_14 has not changed. Therefore, the predicate 'if (i_14 == 1)'
5576 is not visited again, which stops propagation from visiting
5577 statements in the THEN clause of that if().
5579 To properly fix this we would need to keep the previous range
5580 value for the names in the equivalence set. This way we would've
5581 discovered that from one visit to the other i_5 changed from
5582 range [8, 8] to VR_VARYING.
5584 However, fixing this apparent limitation may not be worth the
5585 additional checking. Testing on several code bases (GCC, DLV,
5586 MICO, TRAMP3D and SPEC2000) showed that doing this results in
5587 4 more predicates folded in SPEC. */
5590 val
= vrp_evaluate_conditional_warnv_with_ops (gimple_cond_code (stmt
),
5591 gimple_cond_lhs (stmt
),
5592 gimple_cond_rhs (stmt
),
5597 *taken_edge_p
= find_taken_edge (gimple_bb (stmt
), val
);
5600 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
5602 "\nIgnoring predicate evaluation because "
5603 "it assumes that signed overflow is undefined");
5608 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
5610 fprintf (dump_file
, "\nPredicate evaluates to: ");
5611 if (val
== NULL_TREE
)
5612 fprintf (dump_file
, "DON'T KNOW\n");
5614 print_generic_stmt (dump_file
, val
, 0);
5617 return (*taken_edge_p
) ? SSA_PROP_INTERESTING
: SSA_PROP_VARYING
;
5620 /* Searches the case label vector VEC for the index *IDX of the CASE_LABEL
5621 that includes the value VAL. The search is restricted to the range
5622 [START_IDX, n - 1] where n is the size of VEC.
5624 If there is a CASE_LABEL for VAL, its index is placed in IDX and true is
5627 If there is no CASE_LABEL for VAL and the is one that is larger than VAL,
5628 it is placed in IDX and false is returned.
5630 If VAL is larger than any CASE_LABEL, n is placed on IDX and false is
5634 find_case_label_index (gimple stmt
, size_t start_idx
, tree val
, size_t *idx
)
5636 size_t n
= gimple_switch_num_labels (stmt
);
5639 /* Find case label for minimum of the value range or the next one.
5640 At each iteration we are searching in [low, high - 1]. */
5642 for (low
= start_idx
, high
= n
; high
!= low
; )
5646 /* Note that i != high, so we never ask for n. */
5647 size_t i
= (high
+ low
) / 2;
5648 t
= gimple_switch_label (stmt
, i
);
5650 /* Cache the result of comparing CASE_LOW and val. */
5651 cmp
= tree_int_cst_compare (CASE_LOW (t
), val
);
5655 /* Ranges cannot be empty. */
5664 if (CASE_HIGH (t
) != NULL
5665 && tree_int_cst_compare (CASE_HIGH (t
), val
) >= 0)
5677 /* Searches the case label vector VEC for the range of CASE_LABELs that is used
5678 for values between MIN and MAX. The first index is placed in MIN_IDX. The
5679 last index is placed in MAX_IDX. If the range of CASE_LABELs is empty
5680 then MAX_IDX < MIN_IDX.
5681 Returns true if the default label is not needed. */
5684 find_case_label_range (gimple stmt
, tree min
, tree max
, size_t *min_idx
,
5688 bool min_take_default
= !find_case_label_index (stmt
, 1, min
, &i
);
5689 bool max_take_default
= !find_case_label_index (stmt
, i
, max
, &j
);
5693 && max_take_default
)
5695 /* Only the default case label reached.
5696 Return an empty range. */
5703 bool take_default
= min_take_default
|| max_take_default
;
5707 if (max_take_default
)
5710 /* If the case label range is continuous, we do not need
5711 the default case label. Verify that. */
5712 high
= CASE_LOW (gimple_switch_label (stmt
, i
));
5713 if (CASE_HIGH (gimple_switch_label (stmt
, i
)))
5714 high
= CASE_HIGH (gimple_switch_label (stmt
, i
));
5715 for (k
= i
+ 1; k
<= j
; ++k
)
5717 low
= CASE_LOW (gimple_switch_label (stmt
, k
));
5718 if (!integer_onep (int_const_binop (MINUS_EXPR
, low
, high
, 0)))
5720 take_default
= true;
5724 if (CASE_HIGH (gimple_switch_label (stmt
, k
)))
5725 high
= CASE_HIGH (gimple_switch_label (stmt
, k
));
5730 return !take_default
;
5734 /* Visit switch statement STMT. If we can determine which edge
5735 will be taken out of STMT's basic block, record it in
5736 *TAKEN_EDGE_P and return SSA_PROP_INTERESTING. Otherwise, return
5737 SSA_PROP_VARYING. */
5739 static enum ssa_prop_result
5740 vrp_visit_switch_stmt (gimple stmt
, edge
*taken_edge_p
)
5744 size_t i
= 0, j
= 0, n
;
5747 *taken_edge_p
= NULL
;
5748 op
= gimple_switch_index (stmt
);
5749 if (TREE_CODE (op
) != SSA_NAME
)
5750 return SSA_PROP_VARYING
;
5752 vr
= get_value_range (op
);
5753 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
5755 fprintf (dump_file
, "\nVisiting switch expression with operand ");
5756 print_generic_expr (dump_file
, op
, 0);
5757 fprintf (dump_file
, " with known range ");
5758 dump_value_range (dump_file
, vr
);
5759 fprintf (dump_file
, "\n");
5762 if (vr
->type
!= VR_RANGE
5763 || symbolic_range_p (vr
))
5764 return SSA_PROP_VARYING
;
5766 /* Find the single edge that is taken from the switch expression. */
5767 n
= gimple_switch_num_labels (stmt
);
5769 take_default
= !find_case_label_range (stmt
, vr
->min
, vr
->max
, &i
, &j
);
5771 /* Check if the range spans no CASE_LABEL. If so, we only reach the default
5775 gcc_assert (take_default
);
5776 val
= gimple_switch_default_label (stmt
);
5780 /* Check if labels with index i to j and maybe the default label
5781 are all reaching the same label. */
5783 val
= gimple_switch_label (stmt
, i
);
5785 && CASE_LABEL (gimple_switch_default_label (stmt
))
5786 != CASE_LABEL (val
))
5788 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
5789 fprintf (dump_file
, " not a single destination for this "
5791 return SSA_PROP_VARYING
;
5793 for (++i
; i
<= j
; ++i
)
5795 if (CASE_LABEL (gimple_switch_label (stmt
, i
)) != CASE_LABEL (val
))
5797 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
5798 fprintf (dump_file
, " not a single destination for this "
5800 return SSA_PROP_VARYING
;
5805 *taken_edge_p
= find_edge (gimple_bb (stmt
),
5806 label_to_block (CASE_LABEL (val
)));
5808 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
5810 fprintf (dump_file
, " will take edge to ");
5811 print_generic_stmt (dump_file
, CASE_LABEL (val
), 0);
5814 return SSA_PROP_INTERESTING
;
5818 /* Evaluate statement STMT. If the statement produces a useful range,
5819 return SSA_PROP_INTERESTING and record the SSA name with the
5820 interesting range into *OUTPUT_P.
5822 If STMT is a conditional branch and we can determine its truth
5823 value, the taken edge is recorded in *TAKEN_EDGE_P.
5825 If STMT produces a varying value, return SSA_PROP_VARYING. */
5827 static enum ssa_prop_result
5828 vrp_visit_stmt (gimple stmt
, edge
*taken_edge_p
, tree
*output_p
)
5833 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
5835 fprintf (dump_file
, "\nVisiting statement:\n");
5836 print_gimple_stmt (dump_file
, stmt
, 0, dump_flags
);
5837 fprintf (dump_file
, "\n");
5840 if (is_gimple_assign (stmt
) || is_gimple_call (stmt
))
5842 /* In general, assignments with virtual operands are not useful
5843 for deriving ranges, with the obvious exception of calls to
5844 builtin functions. */
5846 if ((is_gimple_call (stmt
)
5847 && gimple_call_fndecl (stmt
) != NULL_TREE
5848 && DECL_IS_BUILTIN (gimple_call_fndecl (stmt
)))
5849 || ZERO_SSA_OPERANDS (stmt
, SSA_OP_ALL_VIRTUALS
))
5850 return vrp_visit_assignment_or_call (stmt
, output_p
);
5852 else if (gimple_code (stmt
) == GIMPLE_COND
)
5853 return vrp_visit_cond_stmt (stmt
, taken_edge_p
);
5854 else if (gimple_code (stmt
) == GIMPLE_SWITCH
)
5855 return vrp_visit_switch_stmt (stmt
, taken_edge_p
);
5857 /* All other statements produce nothing of interest for VRP, so mark
5858 their outputs varying and prevent further simulation. */
5859 FOR_EACH_SSA_TREE_OPERAND (def
, stmt
, iter
, SSA_OP_DEF
)
5860 set_value_range_to_varying (get_value_range (def
));
5862 return SSA_PROP_VARYING
;
5866 /* Meet operation for value ranges. Given two value ranges VR0 and
5867 VR1, store in VR0 a range that contains both VR0 and VR1. This
5868 may not be the smallest possible such range. */
5871 vrp_meet (value_range_t
*vr0
, value_range_t
*vr1
)
5873 if (vr0
->type
== VR_UNDEFINED
)
5875 copy_value_range (vr0
, vr1
);
5879 if (vr1
->type
== VR_UNDEFINED
)
5881 /* Nothing to do. VR0 already has the resulting range. */
5885 if (vr0
->type
== VR_VARYING
)
5887 /* Nothing to do. VR0 already has the resulting range. */
5891 if (vr1
->type
== VR_VARYING
)
5893 set_value_range_to_varying (vr0
);
5897 if (vr0
->type
== VR_RANGE
&& vr1
->type
== VR_RANGE
)
5902 /* Compute the convex hull of the ranges. The lower limit of
5903 the new range is the minimum of the two ranges. If they
5904 cannot be compared, then give up. */
5905 cmp
= compare_values (vr0
->min
, vr1
->min
);
5906 if (cmp
== 0 || cmp
== 1)
5913 /* Similarly, the upper limit of the new range is the maximum
5914 of the two ranges. If they cannot be compared, then
5916 cmp
= compare_values (vr0
->max
, vr1
->max
);
5917 if (cmp
== 0 || cmp
== -1)
5924 /* Check for useless ranges. */
5925 if (INTEGRAL_TYPE_P (TREE_TYPE (min
))
5926 && ((vrp_val_is_min (min
) || is_overflow_infinity (min
))
5927 && (vrp_val_is_max (max
) || is_overflow_infinity (max
))))
5930 /* The resulting set of equivalences is the intersection of
5932 if (vr0
->equiv
&& vr1
->equiv
&& vr0
->equiv
!= vr1
->equiv
)
5933 bitmap_and_into (vr0
->equiv
, vr1
->equiv
);
5934 else if (vr0
->equiv
&& !vr1
->equiv
)
5935 bitmap_clear (vr0
->equiv
);
5937 set_value_range (vr0
, vr0
->type
, min
, max
, vr0
->equiv
);
5939 else if (vr0
->type
== VR_ANTI_RANGE
&& vr1
->type
== VR_ANTI_RANGE
)
5941 /* Two anti-ranges meet only if their complements intersect.
5942 Only handle the case of identical ranges. */
5943 if (compare_values (vr0
->min
, vr1
->min
) == 0
5944 && compare_values (vr0
->max
, vr1
->max
) == 0
5945 && compare_values (vr0
->min
, vr0
->max
) == 0)
5947 /* The resulting set of equivalences is the intersection of
5949 if (vr0
->equiv
&& vr1
->equiv
&& vr0
->equiv
!= vr1
->equiv
)
5950 bitmap_and_into (vr0
->equiv
, vr1
->equiv
);
5951 else if (vr0
->equiv
&& !vr1
->equiv
)
5952 bitmap_clear (vr0
->equiv
);
5957 else if (vr0
->type
== VR_ANTI_RANGE
|| vr1
->type
== VR_ANTI_RANGE
)
5959 /* For a numeric range [VAL1, VAL2] and an anti-range ~[VAL3, VAL4],
5960 only handle the case where the ranges have an empty intersection.
5961 The result of the meet operation is the anti-range. */
5962 if (!symbolic_range_p (vr0
)
5963 && !symbolic_range_p (vr1
)
5964 && !value_ranges_intersect_p (vr0
, vr1
))
5966 /* Copy most of VR1 into VR0. Don't copy VR1's equivalence
5967 set. We need to compute the intersection of the two
5968 equivalence sets. */
5969 if (vr1
->type
== VR_ANTI_RANGE
)
5970 set_value_range (vr0
, vr1
->type
, vr1
->min
, vr1
->max
, vr0
->equiv
);
5972 /* The resulting set of equivalences is the intersection of
5974 if (vr0
->equiv
&& vr1
->equiv
&& vr0
->equiv
!= vr1
->equiv
)
5975 bitmap_and_into (vr0
->equiv
, vr1
->equiv
);
5976 else if (vr0
->equiv
&& !vr1
->equiv
)
5977 bitmap_clear (vr0
->equiv
);
5988 /* Failed to find an efficient meet. Before giving up and setting
5989 the result to VARYING, see if we can at least derive a useful
5990 anti-range. FIXME, all this nonsense about distinguishing
5991 anti-ranges from ranges is necessary because of the odd
5992 semantics of range_includes_zero_p and friends. */
5993 if (!symbolic_range_p (vr0
)
5994 && ((vr0
->type
== VR_RANGE
&& !range_includes_zero_p (vr0
))
5995 || (vr0
->type
== VR_ANTI_RANGE
&& range_includes_zero_p (vr0
)))
5996 && !symbolic_range_p (vr1
)
5997 && ((vr1
->type
== VR_RANGE
&& !range_includes_zero_p (vr1
))
5998 || (vr1
->type
== VR_ANTI_RANGE
&& range_includes_zero_p (vr1
))))
6000 set_value_range_to_nonnull (vr0
, TREE_TYPE (vr0
->min
));
6002 /* Since this meet operation did not result from the meeting of
6003 two equivalent names, VR0 cannot have any equivalences. */
6005 bitmap_clear (vr0
->equiv
);
6008 set_value_range_to_varying (vr0
);
6012 /* Visit all arguments for PHI node PHI that flow through executable
6013 edges. If a valid value range can be derived from all the incoming
6014 value ranges, set a new range for the LHS of PHI. */
6016 static enum ssa_prop_result
6017 vrp_visit_phi_node (gimple phi
)
6020 tree lhs
= PHI_RESULT (phi
);
6021 value_range_t
*lhs_vr
= get_value_range (lhs
);
6022 value_range_t vr_result
= { VR_UNDEFINED
, NULL_TREE
, NULL_TREE
, NULL
};
6023 int edges
, old_edges
;
6025 copy_value_range (&vr_result
, lhs_vr
);
6027 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
6029 fprintf (dump_file
, "\nVisiting PHI node: ");
6030 print_gimple_stmt (dump_file
, phi
, 0, dump_flags
);
6034 for (i
= 0; i
< gimple_phi_num_args (phi
); i
++)
6036 edge e
= gimple_phi_arg_edge (phi
, i
);
6038 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
6041 "\n Argument #%d (%d -> %d %sexecutable)\n",
6042 (int) i
, e
->src
->index
, e
->dest
->index
,
6043 (e
->flags
& EDGE_EXECUTABLE
) ? "" : "not ");
6046 if (e
->flags
& EDGE_EXECUTABLE
)
6048 tree arg
= PHI_ARG_DEF (phi
, i
);
6049 value_range_t vr_arg
;
6053 if (TREE_CODE (arg
) == SSA_NAME
)
6055 vr_arg
= *(get_value_range (arg
));
6059 if (is_overflow_infinity (arg
))
6061 arg
= copy_node (arg
);
6062 TREE_OVERFLOW (arg
) = 0;
6065 vr_arg
.type
= VR_RANGE
;
6068 vr_arg
.equiv
= NULL
;
6071 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
6073 fprintf (dump_file
, "\t");
6074 print_generic_expr (dump_file
, arg
, dump_flags
);
6075 fprintf (dump_file
, "\n\tValue: ");
6076 dump_value_range (dump_file
, &vr_arg
);
6077 fprintf (dump_file
, "\n");
6080 vrp_meet (&vr_result
, &vr_arg
);
6082 if (vr_result
.type
== VR_VARYING
)
6087 if (vr_result
.type
== VR_VARYING
)
6090 old_edges
= vr_phi_edge_counts
[SSA_NAME_VERSION (lhs
)];
6091 vr_phi_edge_counts
[SSA_NAME_VERSION (lhs
)] = edges
;
6093 /* To prevent infinite iterations in the algorithm, derive ranges
6094 when the new value is slightly bigger or smaller than the
6095 previous one. We don't do this if we have seen a new executable
6096 edge; this helps us avoid an overflow infinity for conditionals
6097 which are not in a loop. */
6098 if (lhs_vr
->type
== VR_RANGE
&& vr_result
.type
== VR_RANGE
6099 && edges
<= old_edges
)
6101 if (!POINTER_TYPE_P (TREE_TYPE (lhs
)))
6103 int cmp_min
= compare_values (lhs_vr
->min
, vr_result
.min
);
6104 int cmp_max
= compare_values (lhs_vr
->max
, vr_result
.max
);
6106 /* If the new minimum is smaller or larger than the previous
6107 one, go all the way to -INF. In the first case, to avoid
6108 iterating millions of times to reach -INF, and in the
6109 other case to avoid infinite bouncing between different
6111 if (cmp_min
> 0 || cmp_min
< 0)
6113 /* If we will end up with a (-INF, +INF) range, set it
6115 if (vrp_val_is_max (vr_result
.max
))
6118 if (!needs_overflow_infinity (TREE_TYPE (vr_result
.min
))
6119 || !vrp_var_may_overflow (lhs
, phi
))
6120 vr_result
.min
= TYPE_MIN_VALUE (TREE_TYPE (vr_result
.min
));
6121 else if (supports_overflow_infinity (TREE_TYPE (vr_result
.min
)))
6123 negative_overflow_infinity (TREE_TYPE (vr_result
.min
));
6128 /* Similarly, if the new maximum is smaller or larger than
6129 the previous one, go all the way to +INF. */
6130 if (cmp_max
< 0 || cmp_max
> 0)
6132 /* If we will end up with a (-INF, +INF) range, set it
6134 if (vrp_val_is_min (vr_result
.min
))
6137 if (!needs_overflow_infinity (TREE_TYPE (vr_result
.max
))
6138 || !vrp_var_may_overflow (lhs
, phi
))
6139 vr_result
.max
= TYPE_MAX_VALUE (TREE_TYPE (vr_result
.max
));
6140 else if (supports_overflow_infinity (TREE_TYPE (vr_result
.max
)))
6142 positive_overflow_infinity (TREE_TYPE (vr_result
.max
));
6149 /* If the new range is different than the previous value, keep
6151 if (update_value_range (lhs
, &vr_result
))
6152 return SSA_PROP_INTERESTING
;
6154 /* Nothing changed, don't add outgoing edges. */
6155 return SSA_PROP_NOT_INTERESTING
;
6157 /* No match found. Set the LHS to VARYING. */
6159 set_value_range_to_varying (lhs_vr
);
6160 return SSA_PROP_VARYING
;
6163 /* Simplify a division or modulo operator to a right shift or
6164 bitwise and if the first operand is unsigned or is greater
6165 than zero and the second operand is an exact power of two. */
6168 simplify_div_or_mod_using_ranges (gimple stmt
)
6170 enum tree_code rhs_code
= gimple_assign_rhs_code (stmt
);
6172 tree op0
= gimple_assign_rhs1 (stmt
);
6173 tree op1
= gimple_assign_rhs2 (stmt
);
6174 value_range_t
*vr
= get_value_range (gimple_assign_rhs1 (stmt
));
6176 if (TYPE_UNSIGNED (TREE_TYPE (op0
)))
6178 val
= integer_one_node
;
6184 val
= compare_range_with_value (GE_EXPR
, vr
, integer_zero_node
, &sop
);
6188 && integer_onep (val
)
6189 && issue_strict_overflow_warning (WARN_STRICT_OVERFLOW_MISC
))
6191 location_t location
;
6193 if (!gimple_has_location (stmt
))
6194 location
= input_location
;
6196 location
= gimple_location (stmt
);
6197 warning (OPT_Wstrict_overflow
,
6198 ("%Hassuming signed overflow does not occur when "
6199 "simplifying / or %% to >> or &"),
6204 if (val
&& integer_onep (val
))
6208 if (rhs_code
== TRUNC_DIV_EXPR
)
6210 t
= build_int_cst (NULL_TREE
, tree_log2 (op1
));
6211 gimple_assign_set_rhs_code (stmt
, RSHIFT_EXPR
);
6212 gimple_assign_set_rhs1 (stmt
, op0
);
6213 gimple_assign_set_rhs2 (stmt
, t
);
6217 t
= build_int_cst (TREE_TYPE (op1
), 1);
6218 t
= int_const_binop (MINUS_EXPR
, op1
, t
, 0);
6219 t
= fold_convert (TREE_TYPE (op0
), t
);
6221 gimple_assign_set_rhs_code (stmt
, BIT_AND_EXPR
);
6222 gimple_assign_set_rhs1 (stmt
, op0
);
6223 gimple_assign_set_rhs2 (stmt
, t
);
6230 /* If the operand to an ABS_EXPR is >= 0, then eliminate the
6231 ABS_EXPR. If the operand is <= 0, then simplify the
6232 ABS_EXPR into a NEGATE_EXPR. */
6235 simplify_abs_using_ranges (gimple stmt
)
6238 tree op
= gimple_assign_rhs1 (stmt
);
6239 tree type
= TREE_TYPE (op
);
6240 value_range_t
*vr
= get_value_range (op
);
6242 if (TYPE_UNSIGNED (type
))
6244 val
= integer_zero_node
;
6250 val
= compare_range_with_value (LE_EXPR
, vr
, integer_zero_node
, &sop
);
6254 val
= compare_range_with_value (GE_EXPR
, vr
, integer_zero_node
,
6259 if (integer_zerop (val
))
6260 val
= integer_one_node
;
6261 else if (integer_onep (val
))
6262 val
= integer_zero_node
;
6267 && (integer_onep (val
) || integer_zerop (val
)))
6269 if (sop
&& issue_strict_overflow_warning (WARN_STRICT_OVERFLOW_MISC
))
6271 location_t location
;
6273 if (!gimple_has_location (stmt
))
6274 location
= input_location
;
6276 location
= gimple_location (stmt
);
6277 warning (OPT_Wstrict_overflow
,
6278 ("%Hassuming signed overflow does not occur when "
6279 "simplifying abs (X) to X or -X"),
6283 gimple_assign_set_rhs1 (stmt
, op
);
6284 if (integer_onep (val
))
6285 gimple_assign_set_rhs_code (stmt
, NEGATE_EXPR
);
6287 gimple_assign_set_rhs_code (stmt
, SSA_NAME
);
6293 /* We are comparing trees OP0 and OP1 using COND_CODE. OP0 has
6294 a known value range VR.
6296 If there is one and only one value which will satisfy the
6297 conditional, then return that value. Else return NULL. */
6300 test_for_singularity (enum tree_code cond_code
, tree op0
,
6301 tree op1
, value_range_t
*vr
)
6306 /* Extract minimum/maximum values which satisfy the
6307 the conditional as it was written. */
6308 if (cond_code
== LE_EXPR
|| cond_code
== LT_EXPR
)
6310 /* This should not be negative infinity; there is no overflow
6312 min
= TYPE_MIN_VALUE (TREE_TYPE (op0
));
6315 if (cond_code
== LT_EXPR
&& !is_overflow_infinity (max
))
6317 tree one
= build_int_cst (TREE_TYPE (op0
), 1);
6318 max
= fold_build2 (MINUS_EXPR
, TREE_TYPE (op0
), max
, one
);
6320 TREE_NO_WARNING (max
) = 1;
6323 else if (cond_code
== GE_EXPR
|| cond_code
== GT_EXPR
)
6325 /* This should not be positive infinity; there is no overflow
6327 max
= TYPE_MAX_VALUE (TREE_TYPE (op0
));
6330 if (cond_code
== GT_EXPR
&& !is_overflow_infinity (min
))
6332 tree one
= build_int_cst (TREE_TYPE (op0
), 1);
6333 min
= fold_build2 (PLUS_EXPR
, TREE_TYPE (op0
), min
, one
);
6335 TREE_NO_WARNING (min
) = 1;
6339 /* Now refine the minimum and maximum values using any
6340 value range information we have for op0. */
6343 if (compare_values (vr
->min
, min
) == -1)
6347 if (compare_values (vr
->max
, max
) == 1)
6352 /* If the new min/max values have converged to a single value,
6353 then there is only one value which can satisfy the condition,
6354 return that value. */
6355 if (operand_equal_p (min
, max
, 0) && is_gimple_min_invariant (min
))
6361 /* Simplify a conditional using a relational operator to an equality
6362 test if the range information indicates only one value can satisfy
6363 the original conditional. */
6366 simplify_cond_using_ranges (gimple stmt
)
6368 tree op0
= gimple_cond_lhs (stmt
);
6369 tree op1
= gimple_cond_rhs (stmt
);
6370 enum tree_code cond_code
= gimple_cond_code (stmt
);
6372 if (cond_code
!= NE_EXPR
6373 && cond_code
!= EQ_EXPR
6374 && TREE_CODE (op0
) == SSA_NAME
6375 && INTEGRAL_TYPE_P (TREE_TYPE (op0
))
6376 && is_gimple_min_invariant (op1
))
6378 value_range_t
*vr
= get_value_range (op0
);
6380 /* If we have range information for OP0, then we might be
6381 able to simplify this conditional. */
6382 if (vr
->type
== VR_RANGE
)
6384 tree new_tree
= test_for_singularity (cond_code
, op0
, op1
, vr
);
6390 fprintf (dump_file
, "Simplified relational ");
6391 print_gimple_stmt (dump_file
, stmt
, 0, 0);
6392 fprintf (dump_file
, " into ");
6395 gimple_cond_set_code (stmt
, EQ_EXPR
);
6396 gimple_cond_set_lhs (stmt
, op0
);
6397 gimple_cond_set_rhs (stmt
, new_tree
);
6403 print_gimple_stmt (dump_file
, stmt
, 0, 0);
6404 fprintf (dump_file
, "\n");
6410 /* Try again after inverting the condition. We only deal
6411 with integral types here, so no need to worry about
6412 issues with inverting FP comparisons. */
6413 cond_code
= invert_tree_comparison (cond_code
, false);
6414 new_tree
= test_for_singularity (cond_code
, op0
, op1
, vr
);
6420 fprintf (dump_file
, "Simplified relational ");
6421 print_gimple_stmt (dump_file
, stmt
, 0, 0);
6422 fprintf (dump_file
, " into ");
6425 gimple_cond_set_code (stmt
, NE_EXPR
);
6426 gimple_cond_set_lhs (stmt
, op0
);
6427 gimple_cond_set_rhs (stmt
, new_tree
);
6433 print_gimple_stmt (dump_file
, stmt
, 0, 0);
6434 fprintf (dump_file
, "\n");
6443 /* Simplify a switch statement using the value range of the switch
6447 simplify_switch_using_ranges (gimple stmt
)
6449 tree op
= gimple_switch_index (stmt
);
6454 size_t i
= 0, j
= 0, n
, n2
;
6458 if (TREE_CODE (op
) != SSA_NAME
)
6461 vr
= get_value_range (op
);
6463 /* We can only handle integer ranges. */
6464 if (vr
->type
!= VR_RANGE
6465 || symbolic_range_p (vr
))
6468 /* Find case label for min/max of the value range. */
6469 n
= gimple_switch_num_labels (stmt
);
6470 take_default
= !find_case_label_range (stmt
, vr
->min
, vr
->max
, &i
, &j
);
6472 /* Bail out if this is just all edges taken. */
6478 /* Build a new vector of taken case labels. */
6479 vec2
= make_tree_vec (j
- i
+ 1 + (int)take_default
);
6482 /* Add the default edge, if necessary. */
6484 TREE_VEC_ELT (vec2
, n2
++) = gimple_switch_default_label (stmt
);
6486 for (; i
<= j
; ++i
, ++n2
)
6487 TREE_VEC_ELT (vec2
, n2
) = gimple_switch_label (stmt
, i
);
6489 /* Mark needed edges. */
6490 for (i
= 0; i
< n2
; ++i
)
6492 e
= find_edge (gimple_bb (stmt
),
6493 label_to_block (CASE_LABEL (TREE_VEC_ELT (vec2
, i
))));
6494 e
->aux
= (void *)-1;
6497 /* Queue not needed edges for later removal. */
6498 FOR_EACH_EDGE (e
, ei
, gimple_bb (stmt
)->succs
)
6500 if (e
->aux
== (void *)-1)
6506 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
6508 fprintf (dump_file
, "removing unreachable case label\n");
6510 VEC_safe_push (edge
, heap
, to_remove_edges
, e
);
6513 /* And queue an update for the stmt. */
6516 VEC_safe_push (switch_update
, heap
, to_update_switch_stmts
, &su
);
6519 /* Simplify STMT using ranges if possible. */
6522 simplify_stmt_using_ranges (gimple stmt
)
6524 if (is_gimple_assign (stmt
))
6526 enum tree_code rhs_code
= gimple_assign_rhs_code (stmt
);
6528 /* Transform TRUNC_DIV_EXPR and TRUNC_MOD_EXPR into RSHIFT_EXPR
6529 and BIT_AND_EXPR respectively if the first operand is greater
6530 than zero and the second operand is an exact power of two. */
6531 if ((rhs_code
== TRUNC_DIV_EXPR
|| rhs_code
== TRUNC_MOD_EXPR
)
6532 && INTEGRAL_TYPE_P (TREE_TYPE (gimple_assign_rhs1 (stmt
)))
6533 && integer_pow2p (gimple_assign_rhs2 (stmt
)))
6534 simplify_div_or_mod_using_ranges (stmt
);
6536 /* Transform ABS (X) into X or -X as appropriate. */
6537 if (rhs_code
== ABS_EXPR
6538 && TREE_CODE (gimple_assign_rhs1 (stmt
)) == SSA_NAME
6539 && INTEGRAL_TYPE_P (TREE_TYPE (gimple_assign_rhs1 (stmt
))))
6540 simplify_abs_using_ranges (stmt
);
6542 else if (gimple_code (stmt
) == GIMPLE_COND
)
6543 simplify_cond_using_ranges (stmt
);
6544 else if (gimple_code (stmt
) == GIMPLE_SWITCH
)
6545 simplify_switch_using_ranges (stmt
);
6548 /* Stack of dest,src equivalency pairs that need to be restored after
6549 each attempt to thread a block's incoming edge to an outgoing edge.
6551 A NULL entry is used to mark the end of pairs which need to be
6553 static VEC(tree
,heap
) *stack
;
6555 /* A trivial wrapper so that we can present the generic jump threading
6556 code with a simple API for simplifying statements. STMT is the
6557 statement we want to simplify, WITHIN_STMT provides the location
6558 for any overflow warnings. */
6561 simplify_stmt_for_jump_threading (gimple stmt
, gimple within_stmt
)
6563 /* We only use VRP information to simplify conditionals. This is
6564 overly conservative, but it's unclear if doing more would be
6565 worth the compile time cost. */
6566 if (gimple_code (stmt
) != GIMPLE_COND
)
6569 return vrp_evaluate_conditional (gimple_cond_code (stmt
),
6570 gimple_cond_lhs (stmt
),
6571 gimple_cond_rhs (stmt
), within_stmt
);
6574 /* Blocks which have more than one predecessor and more than
6575 one successor present jump threading opportunities, i.e.,
6576 when the block is reached from a specific predecessor, we
6577 may be able to determine which of the outgoing edges will
6578 be traversed. When this optimization applies, we are able
6579 to avoid conditionals at runtime and we may expose secondary
6580 optimization opportunities.
6582 This routine is effectively a driver for the generic jump
6583 threading code. It basically just presents the generic code
6584 with edges that may be suitable for jump threading.
6586 Unlike DOM, we do not iterate VRP if jump threading was successful.
6587 While iterating may expose new opportunities for VRP, it is expected
6588 those opportunities would be very limited and the compile time cost
6589 to expose those opportunities would be significant.
6591 As jump threading opportunities are discovered, they are registered
6592 for later realization. */
6595 identify_jump_threads (void)
6602 /* Ugh. When substituting values earlier in this pass we can
6603 wipe the dominance information. So rebuild the dominator
6604 information as we need it within the jump threading code. */
6605 calculate_dominance_info (CDI_DOMINATORS
);
6607 /* We do not allow VRP information to be used for jump threading
6608 across a back edge in the CFG. Otherwise it becomes too
6609 difficult to avoid eliminating loop exit tests. Of course
6610 EDGE_DFS_BACK is not accurate at this time so we have to
6612 mark_dfs_back_edges ();
6614 /* Do not thread across edges we are about to remove. Just marking
6615 them as EDGE_DFS_BACK will do. */
6616 for (i
= 0; VEC_iterate (edge
, to_remove_edges
, i
, e
); ++i
)
6617 e
->flags
|= EDGE_DFS_BACK
;
6619 /* Allocate our unwinder stack to unwind any temporary equivalences
6620 that might be recorded. */
6621 stack
= VEC_alloc (tree
, heap
, 20);
6623 /* To avoid lots of silly node creation, we create a single
6624 conditional and just modify it in-place when attempting to
6626 dummy
= gimple_build_cond (EQ_EXPR
,
6627 integer_zero_node
, integer_zero_node
,
6630 /* Walk through all the blocks finding those which present a
6631 potential jump threading opportunity. We could set this up
6632 as a dominator walker and record data during the walk, but
6633 I doubt it's worth the effort for the classes of jump
6634 threading opportunities we are trying to identify at this
6635 point in compilation. */
6640 /* If the generic jump threading code does not find this block
6641 interesting, then there is nothing to do. */
6642 if (! potentially_threadable_block (bb
))
6645 /* We only care about blocks ending in a COND_EXPR. While there
6646 may be some value in handling SWITCH_EXPR here, I doubt it's
6647 terribly important. */
6648 last
= gsi_stmt (gsi_last_bb (bb
));
6649 if (gimple_code (last
) != GIMPLE_COND
)
6652 /* We're basically looking for any kind of conditional with
6653 integral type arguments. */
6654 if (TREE_CODE (gimple_cond_lhs (last
)) == SSA_NAME
6655 && INTEGRAL_TYPE_P (TREE_TYPE (gimple_cond_lhs (last
)))
6656 && (TREE_CODE (gimple_cond_rhs (last
)) == SSA_NAME
6657 || is_gimple_min_invariant (gimple_cond_rhs (last
)))
6658 && INTEGRAL_TYPE_P (TREE_TYPE (gimple_cond_rhs (last
))))
6662 /* We've got a block with multiple predecessors and multiple
6663 successors which also ends in a suitable conditional. For
6664 each predecessor, see if we can thread it to a specific
6666 FOR_EACH_EDGE (e
, ei
, bb
->preds
)
6668 /* Do not thread across back edges or abnormal edges
6670 if (e
->flags
& (EDGE_DFS_BACK
| EDGE_COMPLEX
))
6673 thread_across_edge (dummy
, e
, true, &stack
,
6674 simplify_stmt_for_jump_threading
);
6679 /* We do not actually update the CFG or SSA graphs at this point as
6680 ASSERT_EXPRs are still in the IL and cfg cleanup code does not yet
6681 handle ASSERT_EXPRs gracefully. */
6684 /* We identified all the jump threading opportunities earlier, but could
6685 not transform the CFG at that time. This routine transforms the
6686 CFG and arranges for the dominator tree to be rebuilt if necessary.
6688 Note the SSA graph update will occur during the normal TODO
6689 processing by the pass manager. */
6691 finalize_jump_threads (void)
6693 thread_through_all_blocks (false);
6694 VEC_free (tree
, heap
, stack
);
6698 /* Traverse all the blocks folding conditionals with known ranges. */
6704 prop_value_t
*single_val_range
;
6705 bool do_value_subst_p
;
6709 fprintf (dump_file
, "\nValue ranges after VRP:\n\n");
6710 dump_all_value_ranges (dump_file
);
6711 fprintf (dump_file
, "\n");
6714 /* We may have ended with ranges that have exactly one value. Those
6715 values can be substituted as any other copy/const propagated
6716 value using substitute_and_fold. */
6717 single_val_range
= XCNEWVEC (prop_value_t
, num_ssa_names
);
6719 do_value_subst_p
= false;
6720 for (i
= 0; i
< num_ssa_names
; i
++)
6722 && vr_value
[i
]->type
== VR_RANGE
6723 && vr_value
[i
]->min
== vr_value
[i
]->max
)
6725 single_val_range
[i
].value
= vr_value
[i
]->min
;
6726 do_value_subst_p
= true;
6729 if (!do_value_subst_p
)
6731 /* We found no single-valued ranges, don't waste time trying to
6732 do single value substitution in substitute_and_fold. */
6733 free (single_val_range
);
6734 single_val_range
= NULL
;
6737 substitute_and_fold (single_val_range
, true);
6739 if (warn_array_bounds
)
6740 check_all_array_refs ();
6742 /* We must identify jump threading opportunities before we release
6743 the datastructures built by VRP. */
6744 identify_jump_threads ();
6746 /* Free allocated memory. */
6747 for (i
= 0; i
< num_ssa_names
; i
++)
6750 BITMAP_FREE (vr_value
[i
]->equiv
);
6754 free (single_val_range
);
6756 free (vr_phi_edge_counts
);
6758 /* So that we can distinguish between VRP data being available
6759 and not available. */
6761 vr_phi_edge_counts
= NULL
;
6765 /* Main entry point to VRP (Value Range Propagation). This pass is
6766 loosely based on J. R. C. Patterson, ``Accurate Static Branch
6767 Prediction by Value Range Propagation,'' in SIGPLAN Conference on
6768 Programming Language Design and Implementation, pp. 67-78, 1995.
6769 Also available at http://citeseer.ist.psu.edu/patterson95accurate.html
6771 This is essentially an SSA-CCP pass modified to deal with ranges
6772 instead of constants.
6774 While propagating ranges, we may find that two or more SSA name
6775 have equivalent, though distinct ranges. For instance,
6778 2 p_4 = ASSERT_EXPR <p_3, p_3 != 0>
6780 4 p_5 = ASSERT_EXPR <p_4, p_4 == q_2>;
6784 In the code above, pointer p_5 has range [q_2, q_2], but from the
6785 code we can also determine that p_5 cannot be NULL and, if q_2 had
6786 a non-varying range, p_5's range should also be compatible with it.
6788 These equivalences are created by two expressions: ASSERT_EXPR and
6789 copy operations. Since p_5 is an assertion on p_4, and p_4 was the
6790 result of another assertion, then we can use the fact that p_5 and
6791 p_4 are equivalent when evaluating p_5's range.
6793 Together with value ranges, we also propagate these equivalences
6794 between names so that we can take advantage of information from
6795 multiple ranges when doing final replacement. Note that this
6796 equivalency relation is transitive but not symmetric.
6798 In the example above, p_5 is equivalent to p_4, q_2 and p_3, but we
6799 cannot assert that q_2 is equivalent to p_5 because q_2 may be used
6800 in contexts where that assertion does not hold (e.g., in line 6).
6802 TODO, the main difference between this pass and Patterson's is that
6803 we do not propagate edge probabilities. We only compute whether
6804 edges can be taken or not. That is, instead of having a spectrum
6805 of jump probabilities between 0 and 1, we only deal with 0, 1 and
6806 DON'T KNOW. In the future, it may be worthwhile to propagate
6807 probabilities to aid branch prediction. */
6816 loop_optimizer_init (LOOPS_NORMAL
| LOOPS_HAVE_RECORDED_EXITS
);
6817 rewrite_into_loop_closed_ssa (NULL
, TODO_update_ssa
);
6820 insert_range_assertions ();
6822 to_remove_edges
= VEC_alloc (edge
, heap
, 10);
6823 to_update_switch_stmts
= VEC_alloc (switch_update
, heap
, 5);
6826 ssa_propagate (vrp_visit_stmt
, vrp_visit_phi_node
);
6829 /* ASSERT_EXPRs must be removed before finalizing jump threads
6830 as finalizing jump threads calls the CFG cleanup code which
6831 does not properly handle ASSERT_EXPRs. */
6832 remove_range_assertions ();
6834 /* If we exposed any new variables, go ahead and put them into
6835 SSA form now, before we handle jump threading. This simplifies
6836 interactions between rewriting of _DECL nodes into SSA form
6837 and rewriting SSA_NAME nodes into SSA form after block
6838 duplication and CFG manipulation. */
6839 update_ssa (TODO_update_ssa
);
6841 finalize_jump_threads ();
6843 /* Remove dead edges from SWITCH_EXPR optimization. This leaves the
6844 CFG in a broken state and requires a cfg_cleanup run. */
6845 for (i
= 0; VEC_iterate (edge
, to_remove_edges
, i
, e
); ++i
)
6847 /* Update SWITCH_EXPR case label vector. */
6848 for (i
= 0; VEC_iterate (switch_update
, to_update_switch_stmts
, i
, su
); ++i
)
6851 size_t n
= TREE_VEC_LENGTH (su
->vec
);
6852 gimple_switch_set_num_labels (su
->stmt
, n
);
6853 for (j
= 0; j
< n
; j
++)
6854 gimple_switch_set_label (su
->stmt
, j
, TREE_VEC_ELT (su
->vec
, j
));
6857 if (VEC_length (edge
, to_remove_edges
) > 0)
6858 free_dominance_info (CDI_DOMINATORS
);
6860 VEC_free (edge
, heap
, to_remove_edges
);
6861 VEC_free (switch_update
, heap
, to_update_switch_stmts
);
6864 loop_optimizer_finalize ();
6871 return flag_tree_vrp
!= 0;
6874 struct gimple_opt_pass pass_vrp
=
6879 gate_vrp
, /* gate */
6880 execute_vrp
, /* execute */
6883 0, /* static_pass_number */
6884 TV_TREE_VRP
, /* tv_id */
6885 PROP_ssa
| PROP_alias
, /* properties_required */
6886 0, /* properties_provided */
6887 0, /* properties_destroyed */
6888 0, /* todo_flags_start */
6893 | TODO_update_ssa
/* todo_flags_finish */