1 /* Support routines for Value Range Propagation (VRP).
2 Copyright (C) 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012
3 Free Software Foundation, Inc.
4 Contributed by Diego Novillo <dnovillo@redhat.com>.
6 This file is part of GCC.
8 GCC is free software; you can redistribute it and/or modify
9 it under the terms of the GNU General Public License as published by
10 the Free Software Foundation; either version 3, or (at your option)
13 GCC is distributed in the hope that it will be useful,
14 but WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 GNU General Public License for more details.
18 You should have received a copy of the GNU General Public License
19 along with GCC; see the file COPYING3. If not see
20 <http://www.gnu.org/licenses/>. */
24 #include "coretypes.h"
29 #include "basic-block.h"
30 #include "tree-flow.h"
31 #include "tree-pass.h"
32 #include "tree-dump.h"
33 #include "gimple-pretty-print.h"
34 #include "diagnostic-core.h"
37 #include "tree-scalar-evolution.h"
38 #include "tree-ssa-propagate.h"
39 #include "tree-chrec.h"
40 #include "gimple-fold.h"
45 /* Type of value ranges. See value_range_d for a description of these
47 enum value_range_type
{ VR_UNDEFINED
, VR_RANGE
, VR_ANTI_RANGE
, VR_VARYING
};
49 /* Range of values that can be associated with an SSA_NAME after VRP
53 /* Lattice value represented by this range. */
54 enum value_range_type type
;
56 /* Minimum and maximum values represented by this range. These
57 values should be interpreted as follows:
59 - If TYPE is VR_UNDEFINED or VR_VARYING then MIN and MAX must
62 - If TYPE == VR_RANGE then MIN holds the minimum value and
63 MAX holds the maximum value of the range [MIN, MAX].
65 - If TYPE == ANTI_RANGE the variable is known to NOT
66 take any values in the range [MIN, MAX]. */
70 /* Set of SSA names whose value ranges are equivalent to this one.
71 This set is only valid when TYPE is VR_RANGE or VR_ANTI_RANGE. */
75 typedef struct value_range_d value_range_t
;
77 #define VR_INITIALIZER { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL }
79 /* Set of SSA names found live during the RPO traversal of the function
80 for still active basic-blocks. */
83 /* Return true if the SSA name NAME is live on the edge E. */
86 live_on_edge (edge e
, tree name
)
88 return (live
[e
->dest
->index
]
89 && TEST_BIT (live
[e
->dest
->index
], SSA_NAME_VERSION (name
)));
92 /* Local functions. */
93 static int compare_values (tree val1
, tree val2
);
94 static int compare_values_warnv (tree val1
, tree val2
, bool *);
95 static void vrp_meet (value_range_t
*, value_range_t
*);
96 static void vrp_intersect_ranges (value_range_t
*, value_range_t
*);
97 static tree
vrp_evaluate_conditional_warnv_with_ops (enum tree_code
,
98 tree
, tree
, bool, bool *,
101 /* Location information for ASSERT_EXPRs. Each instance of this
102 structure describes an ASSERT_EXPR for an SSA name. Since a single
103 SSA name may have more than one assertion associated with it, these
104 locations are kept in a linked list attached to the corresponding
106 struct assert_locus_d
108 /* Basic block where the assertion would be inserted. */
111 /* Some assertions need to be inserted on an edge (e.g., assertions
112 generated by COND_EXPRs). In those cases, BB will be NULL. */
115 /* Pointer to the statement that generated this assertion. */
116 gimple_stmt_iterator si
;
118 /* Predicate code for the ASSERT_EXPR. Must be COMPARISON_CLASS_P. */
119 enum tree_code comp_code
;
121 /* Value being compared against. */
124 /* Expression to compare. */
127 /* Next node in the linked list. */
128 struct assert_locus_d
*next
;
131 typedef struct assert_locus_d
*assert_locus_t
;
133 /* If bit I is present, it means that SSA name N_i has a list of
134 assertions that should be inserted in the IL. */
135 static bitmap need_assert_for
;
137 /* Array of locations lists where to insert assertions. ASSERTS_FOR[I]
138 holds a list of ASSERT_LOCUS_T nodes that describe where
139 ASSERT_EXPRs for SSA name N_I should be inserted. */
140 static assert_locus_t
*asserts_for
;
142 /* Value range array. After propagation, VR_VALUE[I] holds the range
143 of values that SSA name N_I may take. */
144 static unsigned num_vr_values
;
145 static value_range_t
**vr_value
;
146 static bool values_propagated
;
148 /* For a PHI node which sets SSA name N_I, VR_COUNTS[I] holds the
149 number of executable edges we saw the last time we visited the
151 static int *vr_phi_edge_counts
;
158 static VEC (edge
, heap
) *to_remove_edges
;
159 DEF_VEC_O(switch_update
);
160 DEF_VEC_ALLOC_O(switch_update
, heap
);
161 static VEC (switch_update
, heap
) *to_update_switch_stmts
;
164 /* Return the maximum value for TYPE. */
167 vrp_val_max (const_tree type
)
169 if (!INTEGRAL_TYPE_P (type
))
172 return TYPE_MAX_VALUE (type
);
175 /* Return the minimum value for TYPE. */
178 vrp_val_min (const_tree type
)
180 if (!INTEGRAL_TYPE_P (type
))
183 return TYPE_MIN_VALUE (type
);
186 /* Return whether VAL is equal to the maximum value of its type. This
187 will be true for a positive overflow infinity. We can't do a
188 simple equality comparison with TYPE_MAX_VALUE because C typedefs
189 and Ada subtypes can produce types whose TYPE_MAX_VALUE is not ==
190 to the integer constant with the same value in the type. */
193 vrp_val_is_max (const_tree val
)
195 tree type_max
= vrp_val_max (TREE_TYPE (val
));
196 return (val
== type_max
197 || (type_max
!= NULL_TREE
198 && operand_equal_p (val
, type_max
, 0)));
201 /* Return whether VAL is equal to the minimum value of its type. This
202 will be true for a negative overflow infinity. */
205 vrp_val_is_min (const_tree val
)
207 tree type_min
= vrp_val_min (TREE_TYPE (val
));
208 return (val
== type_min
209 || (type_min
!= NULL_TREE
210 && operand_equal_p (val
, type_min
, 0)));
214 /* Return whether TYPE should use an overflow infinity distinct from
215 TYPE_{MIN,MAX}_VALUE. We use an overflow infinity value to
216 represent a signed overflow during VRP computations. An infinity
217 is distinct from a half-range, which will go from some number to
218 TYPE_{MIN,MAX}_VALUE. */
221 needs_overflow_infinity (const_tree type
)
223 return INTEGRAL_TYPE_P (type
) && !TYPE_OVERFLOW_WRAPS (type
);
226 /* Return whether TYPE can support our overflow infinity
227 representation: we use the TREE_OVERFLOW flag, which only exists
228 for constants. If TYPE doesn't support this, we don't optimize
229 cases which would require signed overflow--we drop them to
233 supports_overflow_infinity (const_tree type
)
235 tree min
= vrp_val_min (type
), max
= vrp_val_max (type
);
236 #ifdef ENABLE_CHECKING
237 gcc_assert (needs_overflow_infinity (type
));
239 return (min
!= NULL_TREE
240 && CONSTANT_CLASS_P (min
)
242 && CONSTANT_CLASS_P (max
));
245 /* VAL is the maximum or minimum value of a type. Return a
246 corresponding overflow infinity. */
249 make_overflow_infinity (tree val
)
251 gcc_checking_assert (val
!= NULL_TREE
&& CONSTANT_CLASS_P (val
));
252 val
= copy_node (val
);
253 TREE_OVERFLOW (val
) = 1;
257 /* Return a negative overflow infinity for TYPE. */
260 negative_overflow_infinity (tree type
)
262 gcc_checking_assert (supports_overflow_infinity (type
));
263 return make_overflow_infinity (vrp_val_min (type
));
266 /* Return a positive overflow infinity for TYPE. */
269 positive_overflow_infinity (tree type
)
271 gcc_checking_assert (supports_overflow_infinity (type
));
272 return make_overflow_infinity (vrp_val_max (type
));
275 /* Return whether VAL is a negative overflow infinity. */
278 is_negative_overflow_infinity (const_tree val
)
280 return (needs_overflow_infinity (TREE_TYPE (val
))
281 && CONSTANT_CLASS_P (val
)
282 && TREE_OVERFLOW (val
)
283 && vrp_val_is_min (val
));
286 /* Return whether VAL is a positive overflow infinity. */
289 is_positive_overflow_infinity (const_tree val
)
291 return (needs_overflow_infinity (TREE_TYPE (val
))
292 && CONSTANT_CLASS_P (val
)
293 && TREE_OVERFLOW (val
)
294 && vrp_val_is_max (val
));
297 /* Return whether VAL is a positive or negative overflow infinity. */
300 is_overflow_infinity (const_tree val
)
302 return (needs_overflow_infinity (TREE_TYPE (val
))
303 && CONSTANT_CLASS_P (val
)
304 && TREE_OVERFLOW (val
)
305 && (vrp_val_is_min (val
) || vrp_val_is_max (val
)));
308 /* Return whether STMT has a constant rhs that is_overflow_infinity. */
311 stmt_overflow_infinity (gimple stmt
)
313 if (is_gimple_assign (stmt
)
314 && get_gimple_rhs_class (gimple_assign_rhs_code (stmt
)) ==
316 return is_overflow_infinity (gimple_assign_rhs1 (stmt
));
320 /* If VAL is now an overflow infinity, return VAL. Otherwise, return
321 the same value with TREE_OVERFLOW clear. This can be used to avoid
322 confusing a regular value with an overflow value. */
325 avoid_overflow_infinity (tree val
)
327 if (!is_overflow_infinity (val
))
330 if (vrp_val_is_max (val
))
331 return vrp_val_max (TREE_TYPE (val
));
334 gcc_checking_assert (vrp_val_is_min (val
));
335 return vrp_val_min (TREE_TYPE (val
));
340 /* Return true if ARG is marked with the nonnull attribute in the
341 current function signature. */
344 nonnull_arg_p (const_tree arg
)
346 tree t
, attrs
, fntype
;
347 unsigned HOST_WIDE_INT arg_num
;
349 gcc_assert (TREE_CODE (arg
) == PARM_DECL
&& POINTER_TYPE_P (TREE_TYPE (arg
)));
351 /* The static chain decl is always non null. */
352 if (arg
== cfun
->static_chain_decl
)
355 fntype
= TREE_TYPE (current_function_decl
);
356 for (attrs
= TYPE_ATTRIBUTES (fntype
); attrs
; attrs
= TREE_CHAIN (attrs
))
358 attrs
= lookup_attribute ("nonnull", attrs
);
360 /* If "nonnull" wasn't specified, we know nothing about the argument. */
361 if (attrs
== NULL_TREE
)
364 /* If "nonnull" applies to all the arguments, then ARG is non-null. */
365 if (TREE_VALUE (attrs
) == NULL_TREE
)
368 /* Get the position number for ARG in the function signature. */
369 for (arg_num
= 1, t
= DECL_ARGUMENTS (current_function_decl
);
371 t
= DECL_CHAIN (t
), arg_num
++)
377 gcc_assert (t
== arg
);
379 /* Now see if ARG_NUM is mentioned in the nonnull list. */
380 for (t
= TREE_VALUE (attrs
); t
; t
= TREE_CHAIN (t
))
382 if (compare_tree_int (TREE_VALUE (t
), arg_num
) == 0)
391 /* Set value range VR to VR_UNDEFINED. */
394 set_value_range_to_undefined (value_range_t
*vr
)
396 vr
->type
= VR_UNDEFINED
;
397 vr
->min
= vr
->max
= NULL_TREE
;
399 bitmap_clear (vr
->equiv
);
403 /* Set value range VR to VR_VARYING. */
406 set_value_range_to_varying (value_range_t
*vr
)
408 vr
->type
= VR_VARYING
;
409 vr
->min
= vr
->max
= NULL_TREE
;
411 bitmap_clear (vr
->equiv
);
415 /* Set value range VR to {T, MIN, MAX, EQUIV}. */
418 set_value_range (value_range_t
*vr
, enum value_range_type t
, tree min
,
419 tree max
, bitmap equiv
)
421 #if defined ENABLE_CHECKING
422 /* Check the validity of the range. */
423 if (t
== VR_RANGE
|| t
== VR_ANTI_RANGE
)
427 gcc_assert (min
&& max
);
429 if (INTEGRAL_TYPE_P (TREE_TYPE (min
)) && t
== VR_ANTI_RANGE
)
430 gcc_assert (!vrp_val_is_min (min
) || !vrp_val_is_max (max
));
432 cmp
= compare_values (min
, max
);
433 gcc_assert (cmp
== 0 || cmp
== -1 || cmp
== -2);
435 if (needs_overflow_infinity (TREE_TYPE (min
)))
436 gcc_assert (!is_overflow_infinity (min
)
437 || !is_overflow_infinity (max
));
440 if (t
== VR_UNDEFINED
|| t
== VR_VARYING
)
441 gcc_assert (min
== NULL_TREE
&& max
== NULL_TREE
);
443 if (t
== VR_UNDEFINED
|| t
== VR_VARYING
)
444 gcc_assert (equiv
== NULL
|| bitmap_empty_p (equiv
));
451 /* Since updating the equivalence set involves deep copying the
452 bitmaps, only do it if absolutely necessary. */
453 if (vr
->equiv
== NULL
455 vr
->equiv
= BITMAP_ALLOC (NULL
);
457 if (equiv
!= vr
->equiv
)
459 if (equiv
&& !bitmap_empty_p (equiv
))
460 bitmap_copy (vr
->equiv
, equiv
);
462 bitmap_clear (vr
->equiv
);
467 /* Set value range VR to the canonical form of {T, MIN, MAX, EQUIV}.
468 This means adjusting T, MIN and MAX representing the case of a
469 wrapping range with MAX < MIN covering [MIN, type_max] U [type_min, MAX]
470 as anti-rage ~[MAX+1, MIN-1]. Likewise for wrapping anti-ranges.
471 In corner cases where MAX+1 or MIN-1 wraps this will fall back
473 This routine exists to ease canonicalization in the case where we
474 extract ranges from var + CST op limit. */
477 set_and_canonicalize_value_range (value_range_t
*vr
, enum value_range_type t
,
478 tree min
, tree max
, bitmap equiv
)
480 /* Use the canonical setters for VR_UNDEFINED and VR_VARYING. */
481 if (t
== VR_UNDEFINED
)
483 set_value_range_to_undefined (vr
);
486 else if (t
== VR_VARYING
)
488 set_value_range_to_varying (vr
);
492 /* Nothing to canonicalize for symbolic ranges. */
493 if (TREE_CODE (min
) != INTEGER_CST
494 || TREE_CODE (max
) != INTEGER_CST
)
496 set_value_range (vr
, t
, min
, max
, equiv
);
500 /* Wrong order for min and max, to swap them and the VR type we need
502 if (tree_int_cst_lt (max
, min
))
504 tree one
= build_int_cst (TREE_TYPE (min
), 1);
505 tree tmp
= int_const_binop (PLUS_EXPR
, max
, one
);
506 max
= int_const_binop (MINUS_EXPR
, min
, one
);
509 /* There's one corner case, if we had [C+1, C] before we now have
510 that again. But this represents an empty value range, so drop
511 to varying in this case. */
512 if (tree_int_cst_lt (max
, min
))
514 set_value_range_to_varying (vr
);
518 t
= t
== VR_RANGE
? VR_ANTI_RANGE
: VR_RANGE
;
521 /* Anti-ranges that can be represented as ranges should be so. */
522 if (t
== VR_ANTI_RANGE
)
524 bool is_min
= vrp_val_is_min (min
);
525 bool is_max
= vrp_val_is_max (max
);
527 if (is_min
&& is_max
)
529 /* We cannot deal with empty ranges, drop to varying.
530 ??? This could be VR_UNDEFINED instead. */
531 set_value_range_to_varying (vr
);
535 /* As a special exception preserve non-null ranges. */
536 && !(TYPE_UNSIGNED (TREE_TYPE (min
))
537 && integer_zerop (max
)))
539 tree one
= build_int_cst (TREE_TYPE (max
), 1);
540 min
= int_const_binop (PLUS_EXPR
, max
, one
);
541 max
= vrp_val_max (TREE_TYPE (max
));
546 tree one
= build_int_cst (TREE_TYPE (min
), 1);
547 max
= int_const_binop (MINUS_EXPR
, min
, one
);
548 min
= vrp_val_min (TREE_TYPE (min
));
553 /* Drop [-INF(OVF), +INF(OVF)] to varying. */
554 if (needs_overflow_infinity (TREE_TYPE (min
))
555 && is_overflow_infinity (min
)
556 && is_overflow_infinity (max
))
558 set_value_range_to_varying (vr
);
562 set_value_range (vr
, t
, min
, max
, equiv
);
565 /* Copy value range FROM into value range TO. */
568 copy_value_range (value_range_t
*to
, value_range_t
*from
)
570 set_value_range (to
, from
->type
, from
->min
, from
->max
, from
->equiv
);
573 /* Set value range VR to a single value. This function is only called
574 with values we get from statements, and exists to clear the
575 TREE_OVERFLOW flag so that we don't think we have an overflow
576 infinity when we shouldn't. */
579 set_value_range_to_value (value_range_t
*vr
, tree val
, bitmap equiv
)
581 gcc_assert (is_gimple_min_invariant (val
));
582 val
= avoid_overflow_infinity (val
);
583 set_value_range (vr
, VR_RANGE
, val
, val
, equiv
);
586 /* Set value range VR to a non-negative range of type TYPE.
587 OVERFLOW_INFINITY indicates whether to use an overflow infinity
588 rather than TYPE_MAX_VALUE; this should be true if we determine
589 that the range is nonnegative based on the assumption that signed
590 overflow does not occur. */
593 set_value_range_to_nonnegative (value_range_t
*vr
, tree type
,
594 bool overflow_infinity
)
598 if (overflow_infinity
&& !supports_overflow_infinity (type
))
600 set_value_range_to_varying (vr
);
604 zero
= build_int_cst (type
, 0);
605 set_value_range (vr
, VR_RANGE
, zero
,
607 ? positive_overflow_infinity (type
)
608 : TYPE_MAX_VALUE (type
)),
612 /* Set value range VR to a non-NULL range of type TYPE. */
615 set_value_range_to_nonnull (value_range_t
*vr
, tree type
)
617 tree zero
= build_int_cst (type
, 0);
618 set_value_range (vr
, VR_ANTI_RANGE
, zero
, zero
, vr
->equiv
);
622 /* Set value range VR to a NULL range of type TYPE. */
625 set_value_range_to_null (value_range_t
*vr
, tree type
)
627 set_value_range_to_value (vr
, build_int_cst (type
, 0), vr
->equiv
);
631 /* Set value range VR to a range of a truthvalue of type TYPE. */
634 set_value_range_to_truthvalue (value_range_t
*vr
, tree type
)
636 if (TYPE_PRECISION (type
) == 1)
637 set_value_range_to_varying (vr
);
639 set_value_range (vr
, VR_RANGE
,
640 build_int_cst (type
, 0), build_int_cst (type
, 1),
645 /* If abs (min) < abs (max), set VR to [-max, max], if
646 abs (min) >= abs (max), set VR to [-min, min]. */
649 abs_extent_range (value_range_t
*vr
, tree min
, tree max
)
653 gcc_assert (TREE_CODE (min
) == INTEGER_CST
);
654 gcc_assert (TREE_CODE (max
) == INTEGER_CST
);
655 gcc_assert (INTEGRAL_TYPE_P (TREE_TYPE (min
)));
656 gcc_assert (!TYPE_UNSIGNED (TREE_TYPE (min
)));
657 min
= fold_unary (ABS_EXPR
, TREE_TYPE (min
), min
);
658 max
= fold_unary (ABS_EXPR
, TREE_TYPE (max
), max
);
659 if (TREE_OVERFLOW (min
) || TREE_OVERFLOW (max
))
661 set_value_range_to_varying (vr
);
664 cmp
= compare_values (min
, max
);
666 min
= fold_unary (NEGATE_EXPR
, TREE_TYPE (min
), max
);
667 else if (cmp
== 0 || cmp
== 1)
670 min
= fold_unary (NEGATE_EXPR
, TREE_TYPE (min
), min
);
674 set_value_range_to_varying (vr
);
677 set_and_canonicalize_value_range (vr
, VR_RANGE
, min
, max
, NULL
);
681 /* Return value range information for VAR.
683 If we have no values ranges recorded (ie, VRP is not running), then
684 return NULL. Otherwise create an empty range if none existed for VAR. */
686 static value_range_t
*
687 get_value_range (const_tree var
)
689 static const struct value_range_d vr_const_varying
690 = { VR_VARYING
, NULL_TREE
, NULL_TREE
, NULL
};
693 unsigned ver
= SSA_NAME_VERSION (var
);
695 /* If we have no recorded ranges, then return NULL. */
699 /* If we query the range for a new SSA name return an unmodifiable VARYING.
700 We should get here at most from the substitute-and-fold stage which
701 will never try to change values. */
702 if (ver
>= num_vr_values
)
703 return CONST_CAST (value_range_t
*, &vr_const_varying
);
709 /* After propagation finished do not allocate new value-ranges. */
710 if (values_propagated
)
711 return CONST_CAST (value_range_t
*, &vr_const_varying
);
713 /* Create a default value range. */
714 vr_value
[ver
] = vr
= XCNEW (value_range_t
);
716 /* Defer allocating the equivalence set. */
719 /* If VAR is a default definition of a parameter, the variable can
720 take any value in VAR's type. */
721 sym
= SSA_NAME_VAR (var
);
722 if (SSA_NAME_IS_DEFAULT_DEF (var
))
724 if (TREE_CODE (sym
) == PARM_DECL
)
726 /* Try to use the "nonnull" attribute to create ~[0, 0]
727 anti-ranges for pointers. Note that this is only valid with
728 default definitions of PARM_DECLs. */
729 if (POINTER_TYPE_P (TREE_TYPE (sym
))
730 && nonnull_arg_p (sym
))
731 set_value_range_to_nonnull (vr
, TREE_TYPE (sym
));
733 set_value_range_to_varying (vr
);
735 else if (TREE_CODE (sym
) == RESULT_DECL
736 && DECL_BY_REFERENCE (sym
))
737 set_value_range_to_nonnull (vr
, TREE_TYPE (sym
));
743 /* Return true, if VAL1 and VAL2 are equal values for VRP purposes. */
746 vrp_operand_equal_p (const_tree val1
, const_tree val2
)
750 if (!val1
|| !val2
|| !operand_equal_p (val1
, val2
, 0))
752 if (is_overflow_infinity (val1
))
753 return is_overflow_infinity (val2
);
757 /* Return true, if the bitmaps B1 and B2 are equal. */
760 vrp_bitmap_equal_p (const_bitmap b1
, const_bitmap b2
)
763 || ((!b1
|| bitmap_empty_p (b1
))
764 && (!b2
|| bitmap_empty_p (b2
)))
766 && bitmap_equal_p (b1
, b2
)));
769 /* Update the value range and equivalence set for variable VAR to
770 NEW_VR. Return true if NEW_VR is different from VAR's previous
773 NOTE: This function assumes that NEW_VR is a temporary value range
774 object created for the sole purpose of updating VAR's range. The
775 storage used by the equivalence set from NEW_VR will be freed by
776 this function. Do not call update_value_range when NEW_VR
777 is the range object associated with another SSA name. */
780 update_value_range (const_tree var
, value_range_t
*new_vr
)
782 value_range_t
*old_vr
;
785 /* Update the value range, if necessary. */
786 old_vr
= get_value_range (var
);
787 is_new
= old_vr
->type
!= new_vr
->type
788 || !vrp_operand_equal_p (old_vr
->min
, new_vr
->min
)
789 || !vrp_operand_equal_p (old_vr
->max
, new_vr
->max
)
790 || !vrp_bitmap_equal_p (old_vr
->equiv
, new_vr
->equiv
);
793 set_value_range (old_vr
, new_vr
->type
, new_vr
->min
, new_vr
->max
,
796 BITMAP_FREE (new_vr
->equiv
);
802 /* Add VAR and VAR's equivalence set to EQUIV. This is the central
803 point where equivalence processing can be turned on/off. */
806 add_equivalence (bitmap
*equiv
, const_tree var
)
808 unsigned ver
= SSA_NAME_VERSION (var
);
809 value_range_t
*vr
= vr_value
[ver
];
812 *equiv
= BITMAP_ALLOC (NULL
);
813 bitmap_set_bit (*equiv
, ver
);
815 bitmap_ior_into (*equiv
, vr
->equiv
);
819 /* Return true if VR is ~[0, 0]. */
822 range_is_nonnull (value_range_t
*vr
)
824 return vr
->type
== VR_ANTI_RANGE
825 && integer_zerop (vr
->min
)
826 && integer_zerop (vr
->max
);
830 /* Return true if VR is [0, 0]. */
833 range_is_null (value_range_t
*vr
)
835 return vr
->type
== VR_RANGE
836 && integer_zerop (vr
->min
)
837 && integer_zerop (vr
->max
);
840 /* Return true if max and min of VR are INTEGER_CST. It's not necessary
844 range_int_cst_p (value_range_t
*vr
)
846 return (vr
->type
== VR_RANGE
847 && TREE_CODE (vr
->max
) == INTEGER_CST
848 && TREE_CODE (vr
->min
) == INTEGER_CST
);
851 /* Return true if VR is a INTEGER_CST singleton. */
854 range_int_cst_singleton_p (value_range_t
*vr
)
856 return (range_int_cst_p (vr
)
857 && !TREE_OVERFLOW (vr
->min
)
858 && !TREE_OVERFLOW (vr
->max
)
859 && tree_int_cst_equal (vr
->min
, vr
->max
));
862 /* Return true if value range VR involves at least one symbol. */
865 symbolic_range_p (value_range_t
*vr
)
867 return (!is_gimple_min_invariant (vr
->min
)
868 || !is_gimple_min_invariant (vr
->max
));
871 /* Return true if value range VR uses an overflow infinity. */
874 overflow_infinity_range_p (value_range_t
*vr
)
876 return (vr
->type
== VR_RANGE
877 && (is_overflow_infinity (vr
->min
)
878 || is_overflow_infinity (vr
->max
)));
881 /* Return false if we can not make a valid comparison based on VR;
882 this will be the case if it uses an overflow infinity and overflow
883 is not undefined (i.e., -fno-strict-overflow is in effect).
884 Otherwise return true, and set *STRICT_OVERFLOW_P to true if VR
885 uses an overflow infinity. */
888 usable_range_p (value_range_t
*vr
, bool *strict_overflow_p
)
890 gcc_assert (vr
->type
== VR_RANGE
);
891 if (is_overflow_infinity (vr
->min
))
893 *strict_overflow_p
= true;
894 if (!TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (vr
->min
)))
897 if (is_overflow_infinity (vr
->max
))
899 *strict_overflow_p
= true;
900 if (!TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (vr
->max
)))
907 /* Return true if the result of assignment STMT is know to be non-negative.
908 If the return value is based on the assumption that signed overflow is
909 undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't change
910 *STRICT_OVERFLOW_P.*/
913 gimple_assign_nonnegative_warnv_p (gimple stmt
, bool *strict_overflow_p
)
915 enum tree_code code
= gimple_assign_rhs_code (stmt
);
916 switch (get_gimple_rhs_class (code
))
918 case GIMPLE_UNARY_RHS
:
919 return tree_unary_nonnegative_warnv_p (gimple_assign_rhs_code (stmt
),
920 gimple_expr_type (stmt
),
921 gimple_assign_rhs1 (stmt
),
923 case GIMPLE_BINARY_RHS
:
924 return tree_binary_nonnegative_warnv_p (gimple_assign_rhs_code (stmt
),
925 gimple_expr_type (stmt
),
926 gimple_assign_rhs1 (stmt
),
927 gimple_assign_rhs2 (stmt
),
929 case GIMPLE_TERNARY_RHS
:
931 case GIMPLE_SINGLE_RHS
:
932 return tree_single_nonnegative_warnv_p (gimple_assign_rhs1 (stmt
),
934 case GIMPLE_INVALID_RHS
:
941 /* Return true if return value of call STMT is know to be non-negative.
942 If the return value is based on the assumption that signed overflow is
943 undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't change
944 *STRICT_OVERFLOW_P.*/
947 gimple_call_nonnegative_warnv_p (gimple stmt
, bool *strict_overflow_p
)
949 tree arg0
= gimple_call_num_args (stmt
) > 0 ?
950 gimple_call_arg (stmt
, 0) : NULL_TREE
;
951 tree arg1
= gimple_call_num_args (stmt
) > 1 ?
952 gimple_call_arg (stmt
, 1) : NULL_TREE
;
954 return tree_call_nonnegative_warnv_p (gimple_expr_type (stmt
),
955 gimple_call_fndecl (stmt
),
961 /* Return true if STMT is know to to compute a non-negative value.
962 If the return value is based on the assumption that signed overflow is
963 undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't change
964 *STRICT_OVERFLOW_P.*/
967 gimple_stmt_nonnegative_warnv_p (gimple stmt
, bool *strict_overflow_p
)
969 switch (gimple_code (stmt
))
972 return gimple_assign_nonnegative_warnv_p (stmt
, strict_overflow_p
);
974 return gimple_call_nonnegative_warnv_p (stmt
, strict_overflow_p
);
980 /* Return true if the result of assignment STMT is know to be non-zero.
981 If the return value is based on the assumption that signed overflow is
982 undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't change
983 *STRICT_OVERFLOW_P.*/
986 gimple_assign_nonzero_warnv_p (gimple stmt
, bool *strict_overflow_p
)
988 enum tree_code code
= gimple_assign_rhs_code (stmt
);
989 switch (get_gimple_rhs_class (code
))
991 case GIMPLE_UNARY_RHS
:
992 return tree_unary_nonzero_warnv_p (gimple_assign_rhs_code (stmt
),
993 gimple_expr_type (stmt
),
994 gimple_assign_rhs1 (stmt
),
996 case GIMPLE_BINARY_RHS
:
997 return tree_binary_nonzero_warnv_p (gimple_assign_rhs_code (stmt
),
998 gimple_expr_type (stmt
),
999 gimple_assign_rhs1 (stmt
),
1000 gimple_assign_rhs2 (stmt
),
1002 case GIMPLE_TERNARY_RHS
:
1004 case GIMPLE_SINGLE_RHS
:
1005 return tree_single_nonzero_warnv_p (gimple_assign_rhs1 (stmt
),
1007 case GIMPLE_INVALID_RHS
:
1014 /* Return true if STMT is know to to compute a non-zero value.
1015 If the return value is based on the assumption that signed overflow is
1016 undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't change
1017 *STRICT_OVERFLOW_P.*/
1020 gimple_stmt_nonzero_warnv_p (gimple stmt
, bool *strict_overflow_p
)
1022 switch (gimple_code (stmt
))
1025 return gimple_assign_nonzero_warnv_p (stmt
, strict_overflow_p
);
1027 return gimple_alloca_call_p (stmt
);
1033 /* Like tree_expr_nonzero_warnv_p, but this function uses value ranges
1037 vrp_stmt_computes_nonzero (gimple stmt
, bool *strict_overflow_p
)
1039 if (gimple_stmt_nonzero_warnv_p (stmt
, strict_overflow_p
))
1042 /* If we have an expression of the form &X->a, then the expression
1043 is nonnull if X is nonnull. */
1044 if (is_gimple_assign (stmt
)
1045 && gimple_assign_rhs_code (stmt
) == ADDR_EXPR
)
1047 tree expr
= gimple_assign_rhs1 (stmt
);
1048 tree base
= get_base_address (TREE_OPERAND (expr
, 0));
1050 if (base
!= NULL_TREE
1051 && TREE_CODE (base
) == MEM_REF
1052 && TREE_CODE (TREE_OPERAND (base
, 0)) == SSA_NAME
)
1054 value_range_t
*vr
= get_value_range (TREE_OPERAND (base
, 0));
1055 if (range_is_nonnull (vr
))
1063 /* Returns true if EXPR is a valid value (as expected by compare_values) --
1064 a gimple invariant, or SSA_NAME +- CST. */
1067 valid_value_p (tree expr
)
1069 if (TREE_CODE (expr
) == SSA_NAME
)
1072 if (TREE_CODE (expr
) == PLUS_EXPR
1073 || TREE_CODE (expr
) == MINUS_EXPR
)
1074 return (TREE_CODE (TREE_OPERAND (expr
, 0)) == SSA_NAME
1075 && TREE_CODE (TREE_OPERAND (expr
, 1)) == INTEGER_CST
);
1077 return is_gimple_min_invariant (expr
);
1083 -2 if those are incomparable. */
1085 operand_less_p (tree val
, tree val2
)
1087 /* LT is folded faster than GE and others. Inline the common case. */
1088 if (TREE_CODE (val
) == INTEGER_CST
&& TREE_CODE (val2
) == INTEGER_CST
)
1090 if (TYPE_UNSIGNED (TREE_TYPE (val
)))
1091 return INT_CST_LT_UNSIGNED (val
, val2
);
1094 if (INT_CST_LT (val
, val2
))
1102 fold_defer_overflow_warnings ();
1104 tcmp
= fold_binary_to_constant (LT_EXPR
, boolean_type_node
, val
, val2
);
1106 fold_undefer_and_ignore_overflow_warnings ();
1109 || TREE_CODE (tcmp
) != INTEGER_CST
)
1112 if (!integer_zerop (tcmp
))
1116 /* val >= val2, not considering overflow infinity. */
1117 if (is_negative_overflow_infinity (val
))
1118 return is_negative_overflow_infinity (val2
) ? 0 : 1;
1119 else if (is_positive_overflow_infinity (val2
))
1120 return is_positive_overflow_infinity (val
) ? 0 : 1;
1125 /* Compare two values VAL1 and VAL2. Return
1127 -2 if VAL1 and VAL2 cannot be compared at compile-time,
1130 +1 if VAL1 > VAL2, and
1133 This is similar to tree_int_cst_compare but supports pointer values
1134 and values that cannot be compared at compile time.
1136 If STRICT_OVERFLOW_P is not NULL, then set *STRICT_OVERFLOW_P to
1137 true if the return value is only valid if we assume that signed
1138 overflow is undefined. */
1141 compare_values_warnv (tree val1
, tree val2
, bool *strict_overflow_p
)
1146 /* Below we rely on the fact that VAL1 and VAL2 are both pointers or
1148 gcc_assert (POINTER_TYPE_P (TREE_TYPE (val1
))
1149 == POINTER_TYPE_P (TREE_TYPE (val2
)));
1150 /* Convert the two values into the same type. This is needed because
1151 sizetype causes sign extension even for unsigned types. */
1152 val2
= fold_convert (TREE_TYPE (val1
), val2
);
1153 STRIP_USELESS_TYPE_CONVERSION (val2
);
1155 if ((TREE_CODE (val1
) == SSA_NAME
1156 || TREE_CODE (val1
) == PLUS_EXPR
1157 || TREE_CODE (val1
) == MINUS_EXPR
)
1158 && (TREE_CODE (val2
) == SSA_NAME
1159 || TREE_CODE (val2
) == PLUS_EXPR
1160 || TREE_CODE (val2
) == MINUS_EXPR
))
1162 tree n1
, c1
, n2
, c2
;
1163 enum tree_code code1
, code2
;
1165 /* If VAL1 and VAL2 are of the form 'NAME [+-] CST' or 'NAME',
1166 return -1 or +1 accordingly. If VAL1 and VAL2 don't use the
1167 same name, return -2. */
1168 if (TREE_CODE (val1
) == SSA_NAME
)
1176 code1
= TREE_CODE (val1
);
1177 n1
= TREE_OPERAND (val1
, 0);
1178 c1
= TREE_OPERAND (val1
, 1);
1179 if (tree_int_cst_sgn (c1
) == -1)
1181 if (is_negative_overflow_infinity (c1
))
1183 c1
= fold_unary_to_constant (NEGATE_EXPR
, TREE_TYPE (c1
), c1
);
1186 code1
= code1
== MINUS_EXPR
? PLUS_EXPR
: MINUS_EXPR
;
1190 if (TREE_CODE (val2
) == SSA_NAME
)
1198 code2
= TREE_CODE (val2
);
1199 n2
= TREE_OPERAND (val2
, 0);
1200 c2
= TREE_OPERAND (val2
, 1);
1201 if (tree_int_cst_sgn (c2
) == -1)
1203 if (is_negative_overflow_infinity (c2
))
1205 c2
= fold_unary_to_constant (NEGATE_EXPR
, TREE_TYPE (c2
), c2
);
1208 code2
= code2
== MINUS_EXPR
? PLUS_EXPR
: MINUS_EXPR
;
1212 /* Both values must use the same name. */
1216 if (code1
== SSA_NAME
1217 && code2
== SSA_NAME
)
1221 /* If overflow is defined we cannot simplify more. */
1222 if (!TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (val1
)))
1225 if (strict_overflow_p
!= NULL
1226 && (code1
== SSA_NAME
|| !TREE_NO_WARNING (val1
))
1227 && (code2
== SSA_NAME
|| !TREE_NO_WARNING (val2
)))
1228 *strict_overflow_p
= true;
1230 if (code1
== SSA_NAME
)
1232 if (code2
== PLUS_EXPR
)
1233 /* NAME < NAME + CST */
1235 else if (code2
== MINUS_EXPR
)
1236 /* NAME > NAME - CST */
1239 else if (code1
== PLUS_EXPR
)
1241 if (code2
== SSA_NAME
)
1242 /* NAME + CST > NAME */
1244 else if (code2
== PLUS_EXPR
)
1245 /* NAME + CST1 > NAME + CST2, if CST1 > CST2 */
1246 return compare_values_warnv (c1
, c2
, strict_overflow_p
);
1247 else if (code2
== MINUS_EXPR
)
1248 /* NAME + CST1 > NAME - CST2 */
1251 else if (code1
== MINUS_EXPR
)
1253 if (code2
== SSA_NAME
)
1254 /* NAME - CST < NAME */
1256 else if (code2
== PLUS_EXPR
)
1257 /* NAME - CST1 < NAME + CST2 */
1259 else if (code2
== MINUS_EXPR
)
1260 /* NAME - CST1 > NAME - CST2, if CST1 < CST2. Notice that
1261 C1 and C2 are swapped in the call to compare_values. */
1262 return compare_values_warnv (c2
, c1
, strict_overflow_p
);
1268 /* We cannot compare non-constants. */
1269 if (!is_gimple_min_invariant (val1
) || !is_gimple_min_invariant (val2
))
1272 if (!POINTER_TYPE_P (TREE_TYPE (val1
)))
1274 /* We cannot compare overflowed values, except for overflow
1276 if (TREE_OVERFLOW (val1
) || TREE_OVERFLOW (val2
))
1278 if (strict_overflow_p
!= NULL
)
1279 *strict_overflow_p
= true;
1280 if (is_negative_overflow_infinity (val1
))
1281 return is_negative_overflow_infinity (val2
) ? 0 : -1;
1282 else if (is_negative_overflow_infinity (val2
))
1284 else if (is_positive_overflow_infinity (val1
))
1285 return is_positive_overflow_infinity (val2
) ? 0 : 1;
1286 else if (is_positive_overflow_infinity (val2
))
1291 return tree_int_cst_compare (val1
, val2
);
1297 /* First see if VAL1 and VAL2 are not the same. */
1298 if (val1
== val2
|| operand_equal_p (val1
, val2
, 0))
1301 /* If VAL1 is a lower address than VAL2, return -1. */
1302 if (operand_less_p (val1
, val2
) == 1)
1305 /* If VAL1 is a higher address than VAL2, return +1. */
1306 if (operand_less_p (val2
, val1
) == 1)
1309 /* If VAL1 is different than VAL2, return +2.
1310 For integer constants we either have already returned -1 or 1
1311 or they are equivalent. We still might succeed in proving
1312 something about non-trivial operands. */
1313 if (TREE_CODE (val1
) != INTEGER_CST
1314 || TREE_CODE (val2
) != INTEGER_CST
)
1316 t
= fold_binary_to_constant (NE_EXPR
, boolean_type_node
, val1
, val2
);
1317 if (t
&& integer_onep (t
))
1325 /* Compare values like compare_values_warnv, but treat comparisons of
1326 nonconstants which rely on undefined overflow as incomparable. */
1329 compare_values (tree val1
, tree val2
)
1335 ret
= compare_values_warnv (val1
, val2
, &sop
);
1337 && (!is_gimple_min_invariant (val1
) || !is_gimple_min_invariant (val2
)))
1343 /* Return 1 if VAL is inside value range MIN <= VAL <= MAX,
1344 0 if VAL is not inside [MIN, MAX],
1345 -2 if we cannot tell either way.
1347 Benchmark compile/20001226-1.c compilation time after changing this
1351 value_inside_range (tree val
, tree min
, tree max
)
1355 cmp1
= operand_less_p (val
, min
);
1361 cmp2
= operand_less_p (max
, val
);
1369 /* Return true if value ranges VR0 and VR1 have a non-empty
1372 Benchmark compile/20001226-1.c compilation time after changing this
1377 value_ranges_intersect_p (value_range_t
*vr0
, value_range_t
*vr1
)
1379 /* The value ranges do not intersect if the maximum of the first range is
1380 less than the minimum of the second range or vice versa.
1381 When those relations are unknown, we can't do any better. */
1382 if (operand_less_p (vr0
->max
, vr1
->min
) != 0)
1384 if (operand_less_p (vr1
->max
, vr0
->min
) != 0)
1390 /* Return 1 if [MIN, MAX] includes the value zero, 0 if it does not
1391 include the value zero, -2 if we cannot tell. */
1394 range_includes_zero_p (tree min
, tree max
)
1396 tree zero
= build_int_cst (TREE_TYPE (min
), 0);
1397 return value_inside_range (zero
, min
, max
);
1400 /* Return true if *VR is know to only contain nonnegative values. */
1403 value_range_nonnegative_p (value_range_t
*vr
)
1405 /* Testing for VR_ANTI_RANGE is not useful here as any anti-range
1406 which would return a useful value should be encoded as a
1408 if (vr
->type
== VR_RANGE
)
1410 int result
= compare_values (vr
->min
, integer_zero_node
);
1411 return (result
== 0 || result
== 1);
1417 /* Return true if T, an SSA_NAME, is known to be nonnegative. Return
1418 false otherwise or if no value range information is available. */
1421 ssa_name_nonnegative_p (const_tree t
)
1423 value_range_t
*vr
= get_value_range (t
);
1425 if (INTEGRAL_TYPE_P (t
)
1426 && TYPE_UNSIGNED (t
))
1432 return value_range_nonnegative_p (vr
);
1435 /* If *VR has a value rante that is a single constant value return that,
1436 otherwise return NULL_TREE. */
1439 value_range_constant_singleton (value_range_t
*vr
)
1441 if (vr
->type
== VR_RANGE
1442 && operand_equal_p (vr
->min
, vr
->max
, 0)
1443 && is_gimple_min_invariant (vr
->min
))
1449 /* If OP has a value range with a single constant value return that,
1450 otherwise return NULL_TREE. This returns OP itself if OP is a
1454 op_with_constant_singleton_value_range (tree op
)
1456 if (is_gimple_min_invariant (op
))
1459 if (TREE_CODE (op
) != SSA_NAME
)
1462 return value_range_constant_singleton (get_value_range (op
));
1465 /* Return true if op is in a boolean [0, 1] value-range. */
1468 op_with_boolean_value_range_p (tree op
)
1472 if (TYPE_PRECISION (TREE_TYPE (op
)) == 1)
1475 if (integer_zerop (op
)
1476 || integer_onep (op
))
1479 if (TREE_CODE (op
) != SSA_NAME
)
1482 vr
= get_value_range (op
);
1483 return (vr
->type
== VR_RANGE
1484 && integer_zerop (vr
->min
)
1485 && integer_onep (vr
->max
));
1488 /* Extract value range information from an ASSERT_EXPR EXPR and store
1492 extract_range_from_assert (value_range_t
*vr_p
, tree expr
)
1494 tree var
, cond
, limit
, min
, max
, type
;
1495 value_range_t
*limit_vr
;
1496 enum tree_code cond_code
;
1498 var
= ASSERT_EXPR_VAR (expr
);
1499 cond
= ASSERT_EXPR_COND (expr
);
1501 gcc_assert (COMPARISON_CLASS_P (cond
));
1503 /* Find VAR in the ASSERT_EXPR conditional. */
1504 if (var
== TREE_OPERAND (cond
, 0)
1505 || TREE_CODE (TREE_OPERAND (cond
, 0)) == PLUS_EXPR
1506 || TREE_CODE (TREE_OPERAND (cond
, 0)) == NOP_EXPR
)
1508 /* If the predicate is of the form VAR COMP LIMIT, then we just
1509 take LIMIT from the RHS and use the same comparison code. */
1510 cond_code
= TREE_CODE (cond
);
1511 limit
= TREE_OPERAND (cond
, 1);
1512 cond
= TREE_OPERAND (cond
, 0);
1516 /* If the predicate is of the form LIMIT COMP VAR, then we need
1517 to flip around the comparison code to create the proper range
1519 cond_code
= swap_tree_comparison (TREE_CODE (cond
));
1520 limit
= TREE_OPERAND (cond
, 0);
1521 cond
= TREE_OPERAND (cond
, 1);
1524 limit
= avoid_overflow_infinity (limit
);
1526 type
= TREE_TYPE (var
);
1527 gcc_assert (limit
!= var
);
1529 /* For pointer arithmetic, we only keep track of pointer equality
1531 if (POINTER_TYPE_P (type
) && cond_code
!= NE_EXPR
&& cond_code
!= EQ_EXPR
)
1533 set_value_range_to_varying (vr_p
);
1537 /* If LIMIT is another SSA name and LIMIT has a range of its own,
1538 try to use LIMIT's range to avoid creating symbolic ranges
1540 limit_vr
= (TREE_CODE (limit
) == SSA_NAME
) ? get_value_range (limit
) : NULL
;
1542 /* LIMIT's range is only interesting if it has any useful information. */
1544 && (limit_vr
->type
== VR_UNDEFINED
1545 || limit_vr
->type
== VR_VARYING
1546 || symbolic_range_p (limit_vr
)))
1549 /* Initially, the new range has the same set of equivalences of
1550 VAR's range. This will be revised before returning the final
1551 value. Since assertions may be chained via mutually exclusive
1552 predicates, we will need to trim the set of equivalences before
1554 gcc_assert (vr_p
->equiv
== NULL
);
1555 add_equivalence (&vr_p
->equiv
, var
);
1557 /* Extract a new range based on the asserted comparison for VAR and
1558 LIMIT's value range. Notice that if LIMIT has an anti-range, we
1559 will only use it for equality comparisons (EQ_EXPR). For any
1560 other kind of assertion, we cannot derive a range from LIMIT's
1561 anti-range that can be used to describe the new range. For
1562 instance, ASSERT_EXPR <x_2, x_2 <= b_4>. If b_4 is ~[2, 10],
1563 then b_4 takes on the ranges [-INF, 1] and [11, +INF]. There is
1564 no single range for x_2 that could describe LE_EXPR, so we might
1565 as well build the range [b_4, +INF] for it.
1566 One special case we handle is extracting a range from a
1567 range test encoded as (unsigned)var + CST <= limit. */
1568 if (TREE_CODE (cond
) == NOP_EXPR
1569 || TREE_CODE (cond
) == PLUS_EXPR
)
1571 if (TREE_CODE (cond
) == PLUS_EXPR
)
1573 min
= fold_build1 (NEGATE_EXPR
, TREE_TYPE (TREE_OPERAND (cond
, 1)),
1574 TREE_OPERAND (cond
, 1));
1575 max
= int_const_binop (PLUS_EXPR
, limit
, min
);
1576 cond
= TREE_OPERAND (cond
, 0);
1580 min
= build_int_cst (TREE_TYPE (var
), 0);
1584 /* Make sure to not set TREE_OVERFLOW on the final type
1585 conversion. We are willingly interpreting large positive
1586 unsigned values as negative singed values here. */
1587 min
= force_fit_type_double (TREE_TYPE (var
), tree_to_double_int (min
),
1589 max
= force_fit_type_double (TREE_TYPE (var
), tree_to_double_int (max
),
1592 /* We can transform a max, min range to an anti-range or
1593 vice-versa. Use set_and_canonicalize_value_range which does
1595 if (cond_code
== LE_EXPR
)
1596 set_and_canonicalize_value_range (vr_p
, VR_RANGE
,
1597 min
, max
, vr_p
->equiv
);
1598 else if (cond_code
== GT_EXPR
)
1599 set_and_canonicalize_value_range (vr_p
, VR_ANTI_RANGE
,
1600 min
, max
, vr_p
->equiv
);
1604 else if (cond_code
== EQ_EXPR
)
1606 enum value_range_type range_type
;
1610 range_type
= limit_vr
->type
;
1611 min
= limit_vr
->min
;
1612 max
= limit_vr
->max
;
1616 range_type
= VR_RANGE
;
1621 set_value_range (vr_p
, range_type
, min
, max
, vr_p
->equiv
);
1623 /* When asserting the equality VAR == LIMIT and LIMIT is another
1624 SSA name, the new range will also inherit the equivalence set
1626 if (TREE_CODE (limit
) == SSA_NAME
)
1627 add_equivalence (&vr_p
->equiv
, limit
);
1629 else if (cond_code
== NE_EXPR
)
1631 /* As described above, when LIMIT's range is an anti-range and
1632 this assertion is an inequality (NE_EXPR), then we cannot
1633 derive anything from the anti-range. For instance, if
1634 LIMIT's range was ~[0, 0], the assertion 'VAR != LIMIT' does
1635 not imply that VAR's range is [0, 0]. So, in the case of
1636 anti-ranges, we just assert the inequality using LIMIT and
1639 If LIMIT_VR is a range, we can only use it to build a new
1640 anti-range if LIMIT_VR is a single-valued range. For
1641 instance, if LIMIT_VR is [0, 1], the predicate
1642 VAR != [0, 1] does not mean that VAR's range is ~[0, 1].
1643 Rather, it means that for value 0 VAR should be ~[0, 0]
1644 and for value 1, VAR should be ~[1, 1]. We cannot
1645 represent these ranges.
1647 The only situation in which we can build a valid
1648 anti-range is when LIMIT_VR is a single-valued range
1649 (i.e., LIMIT_VR->MIN == LIMIT_VR->MAX). In that case,
1650 build the anti-range ~[LIMIT_VR->MIN, LIMIT_VR->MAX]. */
1652 && limit_vr
->type
== VR_RANGE
1653 && compare_values (limit_vr
->min
, limit_vr
->max
) == 0)
1655 min
= limit_vr
->min
;
1656 max
= limit_vr
->max
;
1660 /* In any other case, we cannot use LIMIT's range to build a
1661 valid anti-range. */
1665 /* If MIN and MAX cover the whole range for their type, then
1666 just use the original LIMIT. */
1667 if (INTEGRAL_TYPE_P (type
)
1668 && vrp_val_is_min (min
)
1669 && vrp_val_is_max (max
))
1672 set_value_range (vr_p
, VR_ANTI_RANGE
, min
, max
, vr_p
->equiv
);
1674 else if (cond_code
== LE_EXPR
|| cond_code
== LT_EXPR
)
1676 min
= TYPE_MIN_VALUE (type
);
1678 if (limit_vr
== NULL
|| limit_vr
->type
== VR_ANTI_RANGE
)
1682 /* If LIMIT_VR is of the form [N1, N2], we need to build the
1683 range [MIN, N2] for LE_EXPR and [MIN, N2 - 1] for
1685 max
= limit_vr
->max
;
1688 /* If the maximum value forces us to be out of bounds, simply punt.
1689 It would be pointless to try and do anything more since this
1690 all should be optimized away above us. */
1691 if ((cond_code
== LT_EXPR
1692 && compare_values (max
, min
) == 0)
1693 || (CONSTANT_CLASS_P (max
) && TREE_OVERFLOW (max
)))
1694 set_value_range_to_varying (vr_p
);
1697 /* For LT_EXPR, we create the range [MIN, MAX - 1]. */
1698 if (cond_code
== LT_EXPR
)
1700 if (TYPE_PRECISION (TREE_TYPE (max
)) == 1
1701 && !TYPE_UNSIGNED (TREE_TYPE (max
)))
1702 max
= fold_build2 (PLUS_EXPR
, TREE_TYPE (max
), max
,
1703 build_int_cst (TREE_TYPE (max
), -1));
1705 max
= fold_build2 (MINUS_EXPR
, TREE_TYPE (max
), max
,
1706 build_int_cst (TREE_TYPE (max
), 1));
1708 TREE_NO_WARNING (max
) = 1;
1711 set_value_range (vr_p
, VR_RANGE
, min
, max
, vr_p
->equiv
);
1714 else if (cond_code
== GE_EXPR
|| cond_code
== GT_EXPR
)
1716 max
= TYPE_MAX_VALUE (type
);
1718 if (limit_vr
== NULL
|| limit_vr
->type
== VR_ANTI_RANGE
)
1722 /* If LIMIT_VR is of the form [N1, N2], we need to build the
1723 range [N1, MAX] for GE_EXPR and [N1 + 1, MAX] for
1725 min
= limit_vr
->min
;
1728 /* If the minimum value forces us to be out of bounds, simply punt.
1729 It would be pointless to try and do anything more since this
1730 all should be optimized away above us. */
1731 if ((cond_code
== GT_EXPR
1732 && compare_values (min
, max
) == 0)
1733 || (CONSTANT_CLASS_P (min
) && TREE_OVERFLOW (min
)))
1734 set_value_range_to_varying (vr_p
);
1737 /* For GT_EXPR, we create the range [MIN + 1, MAX]. */
1738 if (cond_code
== GT_EXPR
)
1740 if (TYPE_PRECISION (TREE_TYPE (min
)) == 1
1741 && !TYPE_UNSIGNED (TREE_TYPE (min
)))
1742 min
= fold_build2 (MINUS_EXPR
, TREE_TYPE (min
), min
,
1743 build_int_cst (TREE_TYPE (min
), -1));
1745 min
= fold_build2 (PLUS_EXPR
, TREE_TYPE (min
), min
,
1746 build_int_cst (TREE_TYPE (min
), 1));
1748 TREE_NO_WARNING (min
) = 1;
1751 set_value_range (vr_p
, VR_RANGE
, min
, max
, vr_p
->equiv
);
1757 /* Finally intersect the new range with what we already know about var. */
1758 vrp_intersect_ranges (vr_p
, get_value_range (var
));
1762 /* Extract range information from SSA name VAR and store it in VR. If
1763 VAR has an interesting range, use it. Otherwise, create the
1764 range [VAR, VAR] and return it. This is useful in situations where
1765 we may have conditionals testing values of VARYING names. For
1772 Even if y_5 is deemed VARYING, we can determine that x_3 > y_5 is
1776 extract_range_from_ssa_name (value_range_t
*vr
, tree var
)
1778 value_range_t
*var_vr
= get_value_range (var
);
1780 if (var_vr
->type
!= VR_UNDEFINED
&& var_vr
->type
!= VR_VARYING
)
1781 copy_value_range (vr
, var_vr
);
1783 set_value_range (vr
, VR_RANGE
, var
, var
, NULL
);
1785 add_equivalence (&vr
->equiv
, var
);
1789 /* Wrapper around int_const_binop. If the operation overflows and we
1790 are not using wrapping arithmetic, then adjust the result to be
1791 -INF or +INF depending on CODE, VAL1 and VAL2. This can return
1792 NULL_TREE if we need to use an overflow infinity representation but
1793 the type does not support it. */
1796 vrp_int_const_binop (enum tree_code code
, tree val1
, tree val2
)
1800 res
= int_const_binop (code
, val1
, val2
);
1802 /* If we are using unsigned arithmetic, operate symbolically
1803 on -INF and +INF as int_const_binop only handles signed overflow. */
1804 if (TYPE_UNSIGNED (TREE_TYPE (val1
)))
1806 int checkz
= compare_values (res
, val1
);
1807 bool overflow
= false;
1809 /* Ensure that res = val1 [+*] val2 >= val1
1810 or that res = val1 - val2 <= val1. */
1811 if ((code
== PLUS_EXPR
1812 && !(checkz
== 1 || checkz
== 0))
1813 || (code
== MINUS_EXPR
1814 && !(checkz
== 0 || checkz
== -1)))
1818 /* Checking for multiplication overflow is done by dividing the
1819 output of the multiplication by the first input of the
1820 multiplication. If the result of that division operation is
1821 not equal to the second input of the multiplication, then the
1822 multiplication overflowed. */
1823 else if (code
== MULT_EXPR
&& !integer_zerop (val1
))
1825 tree tmp
= int_const_binop (TRUNC_DIV_EXPR
,
1828 int check
= compare_values (tmp
, val2
);
1836 res
= copy_node (res
);
1837 TREE_OVERFLOW (res
) = 1;
1841 else if (TYPE_OVERFLOW_WRAPS (TREE_TYPE (val1
)))
1842 /* If the singed operation wraps then int_const_binop has done
1843 everything we want. */
1845 else if ((TREE_OVERFLOW (res
)
1846 && !TREE_OVERFLOW (val1
)
1847 && !TREE_OVERFLOW (val2
))
1848 || is_overflow_infinity (val1
)
1849 || is_overflow_infinity (val2
))
1851 /* If the operation overflowed but neither VAL1 nor VAL2 are
1852 overflown, return -INF or +INF depending on the operation
1853 and the combination of signs of the operands. */
1854 int sgn1
= tree_int_cst_sgn (val1
);
1855 int sgn2
= tree_int_cst_sgn (val2
);
1857 if (needs_overflow_infinity (TREE_TYPE (res
))
1858 && !supports_overflow_infinity (TREE_TYPE (res
)))
1861 /* We have to punt on adding infinities of different signs,
1862 since we can't tell what the sign of the result should be.
1863 Likewise for subtracting infinities of the same sign. */
1864 if (((code
== PLUS_EXPR
&& sgn1
!= sgn2
)
1865 || (code
== MINUS_EXPR
&& sgn1
== sgn2
))
1866 && is_overflow_infinity (val1
)
1867 && is_overflow_infinity (val2
))
1870 /* Don't try to handle division or shifting of infinities. */
1871 if ((code
== TRUNC_DIV_EXPR
1872 || code
== FLOOR_DIV_EXPR
1873 || code
== CEIL_DIV_EXPR
1874 || code
== EXACT_DIV_EXPR
1875 || code
== ROUND_DIV_EXPR
1876 || code
== RSHIFT_EXPR
)
1877 && (is_overflow_infinity (val1
)
1878 || is_overflow_infinity (val2
)))
1881 /* Notice that we only need to handle the restricted set of
1882 operations handled by extract_range_from_binary_expr.
1883 Among them, only multiplication, addition and subtraction
1884 can yield overflow without overflown operands because we
1885 are working with integral types only... except in the
1886 case VAL1 = -INF and VAL2 = -1 which overflows to +INF
1887 for division too. */
1889 /* For multiplication, the sign of the overflow is given
1890 by the comparison of the signs of the operands. */
1891 if ((code
== MULT_EXPR
&& sgn1
== sgn2
)
1892 /* For addition, the operands must be of the same sign
1893 to yield an overflow. Its sign is therefore that
1894 of one of the operands, for example the first. For
1895 infinite operands X + -INF is negative, not positive. */
1896 || (code
== PLUS_EXPR
1898 ? !is_negative_overflow_infinity (val2
)
1899 : is_positive_overflow_infinity (val2
)))
1900 /* For subtraction, non-infinite operands must be of
1901 different signs to yield an overflow. Its sign is
1902 therefore that of the first operand or the opposite of
1903 that of the second operand. A first operand of 0 counts
1904 as positive here, for the corner case 0 - (-INF), which
1905 overflows, but must yield +INF. For infinite operands 0
1906 - INF is negative, not positive. */
1907 || (code
== MINUS_EXPR
1909 ? !is_positive_overflow_infinity (val2
)
1910 : is_negative_overflow_infinity (val2
)))
1911 /* We only get in here with positive shift count, so the
1912 overflow direction is the same as the sign of val1.
1913 Actually rshift does not overflow at all, but we only
1914 handle the case of shifting overflowed -INF and +INF. */
1915 || (code
== RSHIFT_EXPR
1917 /* For division, the only case is -INF / -1 = +INF. */
1918 || code
== TRUNC_DIV_EXPR
1919 || code
== FLOOR_DIV_EXPR
1920 || code
== CEIL_DIV_EXPR
1921 || code
== EXACT_DIV_EXPR
1922 || code
== ROUND_DIV_EXPR
)
1923 return (needs_overflow_infinity (TREE_TYPE (res
))
1924 ? positive_overflow_infinity (TREE_TYPE (res
))
1925 : TYPE_MAX_VALUE (TREE_TYPE (res
)));
1927 return (needs_overflow_infinity (TREE_TYPE (res
))
1928 ? negative_overflow_infinity (TREE_TYPE (res
))
1929 : TYPE_MIN_VALUE (TREE_TYPE (res
)));
1936 /* For range VR compute two double_int bitmasks. In *MAY_BE_NONZERO
1937 bitmask if some bit is unset, it means for all numbers in the range
1938 the bit is 0, otherwise it might be 0 or 1. In *MUST_BE_NONZERO
1939 bitmask if some bit is set, it means for all numbers in the range
1940 the bit is 1, otherwise it might be 0 or 1. */
1943 zero_nonzero_bits_from_vr (value_range_t
*vr
,
1944 double_int
*may_be_nonzero
,
1945 double_int
*must_be_nonzero
)
1947 *may_be_nonzero
= double_int_minus_one
;
1948 *must_be_nonzero
= double_int_zero
;
1949 if (!range_int_cst_p (vr
)
1950 || TREE_OVERFLOW (vr
->min
)
1951 || TREE_OVERFLOW (vr
->max
))
1954 if (range_int_cst_singleton_p (vr
))
1956 *may_be_nonzero
= tree_to_double_int (vr
->min
);
1957 *must_be_nonzero
= *may_be_nonzero
;
1959 else if (tree_int_cst_sgn (vr
->min
) >= 0
1960 || tree_int_cst_sgn (vr
->max
) < 0)
1962 double_int dmin
= tree_to_double_int (vr
->min
);
1963 double_int dmax
= tree_to_double_int (vr
->max
);
1964 double_int xor_mask
= double_int_xor (dmin
, dmax
);
1965 *may_be_nonzero
= double_int_ior (dmin
, dmax
);
1966 *must_be_nonzero
= double_int_and (dmin
, dmax
);
1967 if (xor_mask
.high
!= 0)
1969 unsigned HOST_WIDE_INT mask
1970 = ((unsigned HOST_WIDE_INT
) 1
1971 << floor_log2 (xor_mask
.high
)) - 1;
1972 may_be_nonzero
->low
= ALL_ONES
;
1973 may_be_nonzero
->high
|= mask
;
1974 must_be_nonzero
->low
= 0;
1975 must_be_nonzero
->high
&= ~mask
;
1977 else if (xor_mask
.low
!= 0)
1979 unsigned HOST_WIDE_INT mask
1980 = ((unsigned HOST_WIDE_INT
) 1
1981 << floor_log2 (xor_mask
.low
)) - 1;
1982 may_be_nonzero
->low
|= mask
;
1983 must_be_nonzero
->low
&= ~mask
;
1990 /* Create two value-ranges in *VR0 and *VR1 from the anti-range *AR
1991 so that *VR0 U *VR1 == *AR. Returns true if that is possible,
1992 false otherwise. If *AR can be represented with a single range
1993 *VR1 will be VR_UNDEFINED. */
1996 ranges_from_anti_range (value_range_t
*ar
,
1997 value_range_t
*vr0
, value_range_t
*vr1
)
1999 tree type
= TREE_TYPE (ar
->min
);
2001 vr0
->type
= VR_UNDEFINED
;
2002 vr1
->type
= VR_UNDEFINED
;
2004 if (ar
->type
!= VR_ANTI_RANGE
2005 || TREE_CODE (ar
->min
) != INTEGER_CST
2006 || TREE_CODE (ar
->max
) != INTEGER_CST
2007 || !vrp_val_min (type
)
2008 || !vrp_val_max (type
))
2011 if (!vrp_val_is_min (ar
->min
))
2013 vr0
->type
= VR_RANGE
;
2014 vr0
->min
= vrp_val_min (type
);
2016 = double_int_to_tree (type
,
2017 double_int_sub (tree_to_double_int (ar
->min
),
2020 if (!vrp_val_is_max (ar
->max
))
2022 vr1
->type
= VR_RANGE
;
2024 = double_int_to_tree (type
,
2025 double_int_add (tree_to_double_int (ar
->max
),
2027 vr1
->max
= vrp_val_max (type
);
2029 if (vr0
->type
== VR_UNDEFINED
)
2032 vr1
->type
= VR_UNDEFINED
;
2035 return vr0
->type
!= VR_UNDEFINED
;
2038 /* Helper to extract a value-range *VR for a multiplicative operation
2042 extract_range_from_multiplicative_op_1 (value_range_t
*vr
,
2043 enum tree_code code
,
2044 value_range_t
*vr0
, value_range_t
*vr1
)
2046 enum value_range_type type
;
2053 /* Multiplications, divisions and shifts are a bit tricky to handle,
2054 depending on the mix of signs we have in the two ranges, we
2055 need to operate on different values to get the minimum and
2056 maximum values for the new range. One approach is to figure
2057 out all the variations of range combinations and do the
2060 However, this involves several calls to compare_values and it
2061 is pretty convoluted. It's simpler to do the 4 operations
2062 (MIN0 OP MIN1, MIN0 OP MAX1, MAX0 OP MIN1 and MAX0 OP MAX0 OP
2063 MAX1) and then figure the smallest and largest values to form
2065 gcc_assert (code
== MULT_EXPR
2066 || code
== TRUNC_DIV_EXPR
2067 || code
== FLOOR_DIV_EXPR
2068 || code
== CEIL_DIV_EXPR
2069 || code
== EXACT_DIV_EXPR
2070 || code
== ROUND_DIV_EXPR
2071 || code
== RSHIFT_EXPR
);
2072 gcc_assert ((vr0
->type
== VR_RANGE
2073 || (code
== MULT_EXPR
&& vr0
->type
== VR_ANTI_RANGE
))
2074 && vr0
->type
== vr1
->type
);
2078 /* Compute the 4 cross operations. */
2080 val
[0] = vrp_int_const_binop (code
, vr0
->min
, vr1
->min
);
2081 if (val
[0] == NULL_TREE
)
2084 if (vr1
->max
== vr1
->min
)
2088 val
[1] = vrp_int_const_binop (code
, vr0
->min
, vr1
->max
);
2089 if (val
[1] == NULL_TREE
)
2093 if (vr0
->max
== vr0
->min
)
2097 val
[2] = vrp_int_const_binop (code
, vr0
->max
, vr1
->min
);
2098 if (val
[2] == NULL_TREE
)
2102 if (vr0
->min
== vr0
->max
|| vr1
->min
== vr1
->max
)
2106 val
[3] = vrp_int_const_binop (code
, vr0
->max
, vr1
->max
);
2107 if (val
[3] == NULL_TREE
)
2113 set_value_range_to_varying (vr
);
2117 /* Set MIN to the minimum of VAL[i] and MAX to the maximum
2121 for (i
= 1; i
< 4; i
++)
2123 if (!is_gimple_min_invariant (min
)
2124 || (TREE_OVERFLOW (min
) && !is_overflow_infinity (min
))
2125 || !is_gimple_min_invariant (max
)
2126 || (TREE_OVERFLOW (max
) && !is_overflow_infinity (max
)))
2131 if (!is_gimple_min_invariant (val
[i
])
2132 || (TREE_OVERFLOW (val
[i
])
2133 && !is_overflow_infinity (val
[i
])))
2135 /* If we found an overflowed value, set MIN and MAX
2136 to it so that we set the resulting range to
2142 if (compare_values (val
[i
], min
) == -1)
2145 if (compare_values (val
[i
], max
) == 1)
2150 /* If either MIN or MAX overflowed, then set the resulting range to
2151 VARYING. But we do accept an overflow infinity
2153 if (min
== NULL_TREE
2154 || !is_gimple_min_invariant (min
)
2155 || (TREE_OVERFLOW (min
) && !is_overflow_infinity (min
))
2157 || !is_gimple_min_invariant (max
)
2158 || (TREE_OVERFLOW (max
) && !is_overflow_infinity (max
)))
2160 set_value_range_to_varying (vr
);
2166 2) [-INF, +-INF(OVF)]
2167 3) [+-INF(OVF), +INF]
2168 4) [+-INF(OVF), +-INF(OVF)]
2169 We learn nothing when we have INF and INF(OVF) on both sides.
2170 Note that we do accept [-INF, -INF] and [+INF, +INF] without
2172 if ((vrp_val_is_min (min
) || is_overflow_infinity (min
))
2173 && (vrp_val_is_max (max
) || is_overflow_infinity (max
)))
2175 set_value_range_to_varying (vr
);
2179 cmp
= compare_values (min
, max
);
2180 if (cmp
== -2 || cmp
== 1)
2182 /* If the new range has its limits swapped around (MIN > MAX),
2183 then the operation caused one of them to wrap around, mark
2184 the new range VARYING. */
2185 set_value_range_to_varying (vr
);
2188 set_value_range (vr
, type
, min
, max
, NULL
);
2191 /* Extract range information from a binary operation CODE based on
2192 the ranges of each of its operands, *VR0 and *VR1 with resulting
2193 type EXPR_TYPE. The resulting range is stored in *VR. */
2196 extract_range_from_binary_expr_1 (value_range_t
*vr
,
2197 enum tree_code code
, tree expr_type
,
2198 value_range_t
*vr0_
, value_range_t
*vr1_
)
2200 value_range_t vr0
= *vr0_
, vr1
= *vr1_
;
2201 value_range_t vrtem0
= VR_INITIALIZER
, vrtem1
= VR_INITIALIZER
;
2202 enum value_range_type type
;
2203 tree min
= NULL_TREE
, max
= NULL_TREE
;
2206 if (!INTEGRAL_TYPE_P (expr_type
)
2207 && !POINTER_TYPE_P (expr_type
))
2209 set_value_range_to_varying (vr
);
2213 /* Not all binary expressions can be applied to ranges in a
2214 meaningful way. Handle only arithmetic operations. */
2215 if (code
!= PLUS_EXPR
2216 && code
!= MINUS_EXPR
2217 && code
!= POINTER_PLUS_EXPR
2218 && code
!= MULT_EXPR
2219 && code
!= TRUNC_DIV_EXPR
2220 && code
!= FLOOR_DIV_EXPR
2221 && code
!= CEIL_DIV_EXPR
2222 && code
!= EXACT_DIV_EXPR
2223 && code
!= ROUND_DIV_EXPR
2224 && code
!= TRUNC_MOD_EXPR
2225 && code
!= RSHIFT_EXPR
2226 && code
!= LSHIFT_EXPR
2229 && code
!= BIT_AND_EXPR
2230 && code
!= BIT_IOR_EXPR
2231 && code
!= BIT_XOR_EXPR
)
2233 set_value_range_to_varying (vr
);
2237 /* If both ranges are UNDEFINED, so is the result. */
2238 if (vr0
.type
== VR_UNDEFINED
&& vr1
.type
== VR_UNDEFINED
)
2240 set_value_range_to_undefined (vr
);
2243 /* If one of the ranges is UNDEFINED drop it to VARYING for the following
2244 code. At some point we may want to special-case operations that
2245 have UNDEFINED result for all or some value-ranges of the not UNDEFINED
2247 else if (vr0
.type
== VR_UNDEFINED
)
2248 set_value_range_to_varying (&vr0
);
2249 else if (vr1
.type
== VR_UNDEFINED
)
2250 set_value_range_to_varying (&vr1
);
2252 /* Now canonicalize anti-ranges to ranges when they are not symbolic
2253 and express ~[] op X as ([]' op X) U ([]'' op X). */
2254 if (vr0
.type
== VR_ANTI_RANGE
2255 && ranges_from_anti_range (&vr0
, &vrtem0
, &vrtem1
))
2257 extract_range_from_binary_expr_1 (vr
, code
, expr_type
, &vrtem0
, vr1_
);
2258 if (vrtem1
.type
!= VR_UNDEFINED
)
2260 value_range_t vrres
= VR_INITIALIZER
;
2261 extract_range_from_binary_expr_1 (&vrres
, code
, expr_type
,
2263 vrp_meet (vr
, &vrres
);
2267 /* Likewise for X op ~[]. */
2268 if (vr1
.type
== VR_ANTI_RANGE
2269 && ranges_from_anti_range (&vr1
, &vrtem0
, &vrtem1
))
2271 extract_range_from_binary_expr_1 (vr
, code
, expr_type
, vr0_
, &vrtem0
);
2272 if (vrtem1
.type
!= VR_UNDEFINED
)
2274 value_range_t vrres
= VR_INITIALIZER
;
2275 extract_range_from_binary_expr_1 (&vrres
, code
, expr_type
,
2277 vrp_meet (vr
, &vrres
);
2282 /* The type of the resulting value range defaults to VR0.TYPE. */
2285 /* Refuse to operate on VARYING ranges, ranges of different kinds
2286 and symbolic ranges. As an exception, we allow BIT_AND_EXPR
2287 because we may be able to derive a useful range even if one of
2288 the operands is VR_VARYING or symbolic range. Similarly for
2289 divisions. TODO, we may be able to derive anti-ranges in
2291 if (code
!= BIT_AND_EXPR
2292 && code
!= BIT_IOR_EXPR
2293 && code
!= TRUNC_DIV_EXPR
2294 && code
!= FLOOR_DIV_EXPR
2295 && code
!= CEIL_DIV_EXPR
2296 && code
!= EXACT_DIV_EXPR
2297 && code
!= ROUND_DIV_EXPR
2298 && code
!= TRUNC_MOD_EXPR
2299 && (vr0
.type
== VR_VARYING
2300 || vr1
.type
== VR_VARYING
2301 || vr0
.type
!= vr1
.type
2302 || symbolic_range_p (&vr0
)
2303 || symbolic_range_p (&vr1
)))
2305 set_value_range_to_varying (vr
);
2309 /* Now evaluate the expression to determine the new range. */
2310 if (POINTER_TYPE_P (expr_type
))
2312 if (code
== MIN_EXPR
|| code
== MAX_EXPR
)
2314 /* For MIN/MAX expressions with pointers, we only care about
2315 nullness, if both are non null, then the result is nonnull.
2316 If both are null, then the result is null. Otherwise they
2318 if (range_is_nonnull (&vr0
) && range_is_nonnull (&vr1
))
2319 set_value_range_to_nonnull (vr
, expr_type
);
2320 else if (range_is_null (&vr0
) && range_is_null (&vr1
))
2321 set_value_range_to_null (vr
, expr_type
);
2323 set_value_range_to_varying (vr
);
2325 else if (code
== POINTER_PLUS_EXPR
)
2327 /* For pointer types, we are really only interested in asserting
2328 whether the expression evaluates to non-NULL. */
2329 if (range_is_nonnull (&vr0
) || range_is_nonnull (&vr1
))
2330 set_value_range_to_nonnull (vr
, expr_type
);
2331 else if (range_is_null (&vr0
) && range_is_null (&vr1
))
2332 set_value_range_to_null (vr
, expr_type
);
2334 set_value_range_to_varying (vr
);
2336 else if (code
== BIT_AND_EXPR
)
2338 /* For pointer types, we are really only interested in asserting
2339 whether the expression evaluates to non-NULL. */
2340 if (range_is_nonnull (&vr0
) && range_is_nonnull (&vr1
))
2341 set_value_range_to_nonnull (vr
, expr_type
);
2342 else if (range_is_null (&vr0
) || range_is_null (&vr1
))
2343 set_value_range_to_null (vr
, expr_type
);
2345 set_value_range_to_varying (vr
);
2348 set_value_range_to_varying (vr
);
2353 /* For integer ranges, apply the operation to each end of the
2354 range and see what we end up with. */
2355 if (code
== PLUS_EXPR
|| code
== MINUS_EXPR
)
2357 /* If we have a PLUS_EXPR with two VR_RANGE integer constant
2358 ranges compute the precise range for such case if possible. */
2359 if (range_int_cst_p (&vr0
)
2360 && range_int_cst_p (&vr1
)
2361 /* We need as many bits as the possibly unsigned inputs. */
2362 && TYPE_PRECISION (expr_type
) <= HOST_BITS_PER_DOUBLE_INT
)
2364 double_int min0
= tree_to_double_int (vr0
.min
);
2365 double_int max0
= tree_to_double_int (vr0
.max
);
2366 double_int min1
= tree_to_double_int (vr1
.min
);
2367 double_int max1
= tree_to_double_int (vr1
.max
);
2368 bool uns
= TYPE_UNSIGNED (expr_type
);
2370 = double_int_min_value (TYPE_PRECISION (expr_type
), uns
);
2372 = double_int_max_value (TYPE_PRECISION (expr_type
), uns
);
2373 double_int dmin
, dmax
;
2377 if (code
== PLUS_EXPR
)
2379 dmin
= double_int_add (min0
, min1
);
2380 dmax
= double_int_add (max0
, max1
);
2382 /* Check for overflow in double_int. */
2383 if (double_int_cmp (min1
, double_int_zero
, uns
)
2384 != double_int_cmp (dmin
, min0
, uns
))
2385 min_ovf
= double_int_cmp (min0
, dmin
, uns
);
2386 if (double_int_cmp (max1
, double_int_zero
, uns
)
2387 != double_int_cmp (dmax
, max0
, uns
))
2388 max_ovf
= double_int_cmp (max0
, dmax
, uns
);
2390 else /* if (code == MINUS_EXPR) */
2392 dmin
= double_int_sub (min0
, max1
);
2393 dmax
= double_int_sub (max0
, min1
);
2395 if (double_int_cmp (double_int_zero
, max1
, uns
)
2396 != double_int_cmp (dmin
, min0
, uns
))
2397 min_ovf
= double_int_cmp (min0
, max1
, uns
);
2398 if (double_int_cmp (double_int_zero
, min1
, uns
)
2399 != double_int_cmp (dmax
, max0
, uns
))
2400 max_ovf
= double_int_cmp (max0
, min1
, uns
);
2403 /* For non-wrapping arithmetic look at possibly smaller
2404 value-ranges of the type. */
2405 if (!TYPE_OVERFLOW_WRAPS (expr_type
))
2407 if (vrp_val_min (expr_type
))
2408 type_min
= tree_to_double_int (vrp_val_min (expr_type
));
2409 if (vrp_val_max (expr_type
))
2410 type_max
= tree_to_double_int (vrp_val_max (expr_type
));
2413 /* Check for type overflow. */
2416 if (double_int_cmp (dmin
, type_min
, uns
) == -1)
2418 else if (double_int_cmp (dmin
, type_max
, uns
) == 1)
2423 if (double_int_cmp (dmax
, type_min
, uns
) == -1)
2425 else if (double_int_cmp (dmax
, type_max
, uns
) == 1)
2429 if (TYPE_OVERFLOW_WRAPS (expr_type
))
2431 /* If overflow wraps, truncate the values and adjust the
2432 range kind and bounds appropriately. */
2434 = double_int_ext (dmin
, TYPE_PRECISION (expr_type
), uns
);
2436 = double_int_ext (dmax
, TYPE_PRECISION (expr_type
), uns
);
2437 if (min_ovf
== max_ovf
)
2439 /* No overflow or both overflow or underflow. The
2440 range kind stays VR_RANGE. */
2441 min
= double_int_to_tree (expr_type
, tmin
);
2442 max
= double_int_to_tree (expr_type
, tmax
);
2444 else if (min_ovf
== -1
2447 /* Underflow and overflow, drop to VR_VARYING. */
2448 set_value_range_to_varying (vr
);
2453 /* Min underflow or max overflow. The range kind
2454 changes to VR_ANTI_RANGE. */
2455 double_int tem
= tmin
;
2456 gcc_assert ((min_ovf
== -1 && max_ovf
== 0)
2457 || (max_ovf
== 1 && min_ovf
== 0));
2458 type
= VR_ANTI_RANGE
;
2459 tmin
= double_int_add (tmax
, double_int_one
);
2460 tmax
= double_int_add (tem
, double_int_minus_one
);
2461 /* If the anti-range would cover nothing, drop to varying.
2462 Likewise if the anti-range bounds are outside of the
2464 if (double_int_cmp (tmin
, tmax
, uns
) > 0
2465 || double_int_cmp (tmin
, type_min
, uns
) < 0
2466 || double_int_cmp (tmax
, type_max
, uns
) > 0)
2468 set_value_range_to_varying (vr
);
2471 min
= double_int_to_tree (expr_type
, tmin
);
2472 max
= double_int_to_tree (expr_type
, tmax
);
2477 /* If overflow does not wrap, saturate to the types min/max
2481 if (needs_overflow_infinity (expr_type
)
2482 && supports_overflow_infinity (expr_type
))
2483 min
= negative_overflow_infinity (expr_type
);
2485 min
= double_int_to_tree (expr_type
, type_min
);
2487 else if (min_ovf
== 1)
2489 if (needs_overflow_infinity (expr_type
)
2490 && supports_overflow_infinity (expr_type
))
2491 min
= positive_overflow_infinity (expr_type
);
2493 min
= double_int_to_tree (expr_type
, type_max
);
2496 min
= double_int_to_tree (expr_type
, dmin
);
2500 if (needs_overflow_infinity (expr_type
)
2501 && supports_overflow_infinity (expr_type
))
2502 max
= negative_overflow_infinity (expr_type
);
2504 max
= double_int_to_tree (expr_type
, type_min
);
2506 else if (max_ovf
== 1)
2508 if (needs_overflow_infinity (expr_type
)
2509 && supports_overflow_infinity (expr_type
))
2510 max
= positive_overflow_infinity (expr_type
);
2512 max
= double_int_to_tree (expr_type
, type_max
);
2515 max
= double_int_to_tree (expr_type
, dmax
);
2517 if (needs_overflow_infinity (expr_type
)
2518 && supports_overflow_infinity (expr_type
))
2520 if (is_negative_overflow_infinity (vr0
.min
)
2521 || (code
== PLUS_EXPR
2522 ? is_negative_overflow_infinity (vr1
.min
)
2523 : is_positive_overflow_infinity (vr1
.max
)))
2524 min
= negative_overflow_infinity (expr_type
);
2525 if (is_positive_overflow_infinity (vr0
.max
)
2526 || (code
== PLUS_EXPR
2527 ? is_positive_overflow_infinity (vr1
.max
)
2528 : is_negative_overflow_infinity (vr1
.min
)))
2529 max
= positive_overflow_infinity (expr_type
);
2534 /* For other cases, for example if we have a PLUS_EXPR with two
2535 VR_ANTI_RANGEs, drop to VR_VARYING. It would take more effort
2536 to compute a precise range for such a case.
2537 ??? General even mixed range kind operations can be expressed
2538 by for example transforming ~[3, 5] + [1, 2] to range-only
2539 operations and a union primitive:
2540 [-INF, 2] + [1, 2] U [5, +INF] + [1, 2]
2541 [-INF+1, 4] U [6, +INF(OVF)]
2542 though usually the union is not exactly representable with
2543 a single range or anti-range as the above is
2544 [-INF+1, +INF(OVF)] intersected with ~[5, 5]
2545 but one could use a scheme similar to equivalences for this. */
2546 set_value_range_to_varying (vr
);
2550 else if (code
== MIN_EXPR
2551 || code
== MAX_EXPR
)
2553 if (vr0
.type
== VR_ANTI_RANGE
)
2555 /* For MIN_EXPR and MAX_EXPR with two VR_ANTI_RANGEs,
2556 the resulting VR_ANTI_RANGE is the same - intersection
2557 of the two ranges. */
2558 min
= vrp_int_const_binop (MAX_EXPR
, vr0
.min
, vr1
.min
);
2559 max
= vrp_int_const_binop (MIN_EXPR
, vr0
.max
, vr1
.max
);
2563 /* For operations that make the resulting range directly
2564 proportional to the original ranges, apply the operation to
2565 the same end of each range. */
2566 min
= vrp_int_const_binop (code
, vr0
.min
, vr1
.min
);
2567 max
= vrp_int_const_binop (code
, vr0
.max
, vr1
.max
);
2570 else if (code
== MULT_EXPR
)
2572 /* If we have an unsigned MULT_EXPR with two VR_ANTI_RANGEs,
2573 drop to VR_VARYING. It would take more effort to compute a
2574 precise range for such a case. For example, if we have
2575 op0 == 65536 and op1 == 65536 with their ranges both being
2576 ~[0,0] on a 32-bit machine, we would have op0 * op1 == 0, so
2577 we cannot claim that the product is in ~[0,0]. Note that we
2578 are guaranteed to have vr0.type == vr1.type at this
2580 if (vr0
.type
== VR_ANTI_RANGE
2581 && !TYPE_OVERFLOW_UNDEFINED (expr_type
))
2583 set_value_range_to_varying (vr
);
2587 extract_range_from_multiplicative_op_1 (vr
, code
, &vr0
, &vr1
);
2590 else if (code
== RSHIFT_EXPR
)
2592 /* If we have a RSHIFT_EXPR with any shift values outside [0..prec-1],
2593 then drop to VR_VARYING. Outside of this range we get undefined
2594 behavior from the shift operation. We cannot even trust
2595 SHIFT_COUNT_TRUNCATED at this stage, because that applies to rtl
2596 shifts, and the operation at the tree level may be widened. */
2597 if (vr1
.type
!= VR_RANGE
2598 || !value_range_nonnegative_p (&vr1
)
2599 || TREE_CODE (vr1
.max
) != INTEGER_CST
2600 || compare_tree_int (vr1
.max
, TYPE_PRECISION (expr_type
) - 1) == 1)
2602 set_value_range_to_varying (vr
);
2606 extract_range_from_multiplicative_op_1 (vr
, code
, &vr0
, &vr1
);
2609 else if (code
== LSHIFT_EXPR
)
2611 /* If we have a LSHIFT_EXPR with any shift values outside [0..prec-1],
2612 then drop to VR_VARYING. Outside of this range we get undefined
2613 behavior from the shift operation. We cannot even trust
2614 SHIFT_COUNT_TRUNCATED at this stage, because that applies to rtl
2615 shifts, and the operation at the tree level may be widened. */
2616 if (vr1
.type
!= VR_RANGE
2617 || !value_range_nonnegative_p (&vr1
)
2618 || TREE_CODE (vr1
.max
) != INTEGER_CST
2619 || compare_tree_int (vr1
.max
, TYPE_PRECISION (expr_type
) - 1) == 1)
2621 set_value_range_to_varying (vr
);
2625 /* We can map shifts by constants to MULT_EXPR handling. */
2626 if (range_int_cst_singleton_p (&vr1
))
2628 value_range_t vr1p
= VR_INITIALIZER
;
2629 vr1p
.type
= VR_RANGE
;
2631 = double_int_to_tree (expr_type
,
2632 double_int_lshift (double_int_one
,
2633 TREE_INT_CST_LOW (vr1
.min
),
2634 TYPE_PRECISION (expr_type
),
2636 vr1p
.max
= vr1p
.min
;
2637 extract_range_from_multiplicative_op_1 (vr
, MULT_EXPR
, &vr0
, &vr1p
);
2641 set_value_range_to_varying (vr
);
2644 else if (code
== TRUNC_DIV_EXPR
2645 || code
== FLOOR_DIV_EXPR
2646 || code
== CEIL_DIV_EXPR
2647 || code
== EXACT_DIV_EXPR
2648 || code
== ROUND_DIV_EXPR
)
2650 if (vr0
.type
!= VR_RANGE
|| symbolic_range_p (&vr0
))
2652 /* For division, if op1 has VR_RANGE but op0 does not, something
2653 can be deduced just from that range. Say [min, max] / [4, max]
2654 gives [min / 4, max / 4] range. */
2655 if (vr1
.type
== VR_RANGE
2656 && !symbolic_range_p (&vr1
)
2657 && range_includes_zero_p (vr1
.min
, vr1
.max
) == 0)
2659 vr0
.type
= type
= VR_RANGE
;
2660 vr0
.min
= vrp_val_min (expr_type
);
2661 vr0
.max
= vrp_val_max (expr_type
);
2665 set_value_range_to_varying (vr
);
2670 /* For divisions, if flag_non_call_exceptions is true, we must
2671 not eliminate a division by zero. */
2672 if (cfun
->can_throw_non_call_exceptions
2673 && (vr1
.type
!= VR_RANGE
2674 || range_includes_zero_p (vr1
.min
, vr1
.max
) != 0))
2676 set_value_range_to_varying (vr
);
2680 /* For divisions, if op0 is VR_RANGE, we can deduce a range
2681 even if op1 is VR_VARYING, VR_ANTI_RANGE, symbolic or can
2683 if (vr0
.type
== VR_RANGE
2684 && (vr1
.type
!= VR_RANGE
2685 || range_includes_zero_p (vr1
.min
, vr1
.max
) != 0))
2687 tree zero
= build_int_cst (TREE_TYPE (vr0
.min
), 0);
2692 if (TYPE_UNSIGNED (expr_type
)
2693 || value_range_nonnegative_p (&vr1
))
2695 /* For unsigned division or when divisor is known
2696 to be non-negative, the range has to cover
2697 all numbers from 0 to max for positive max
2698 and all numbers from min to 0 for negative min. */
2699 cmp
= compare_values (vr0
.max
, zero
);
2702 else if (cmp
== 0 || cmp
== 1)
2706 cmp
= compare_values (vr0
.min
, zero
);
2709 else if (cmp
== 0 || cmp
== -1)
2716 /* Otherwise the range is -max .. max or min .. -min
2717 depending on which bound is bigger in absolute value,
2718 as the division can change the sign. */
2719 abs_extent_range (vr
, vr0
.min
, vr0
.max
);
2722 if (type
== VR_VARYING
)
2724 set_value_range_to_varying (vr
);
2730 extract_range_from_multiplicative_op_1 (vr
, code
, &vr0
, &vr1
);
2734 else if (code
== TRUNC_MOD_EXPR
)
2736 if (vr1
.type
!= VR_RANGE
2737 || range_includes_zero_p (vr1
.min
, vr1
.max
) != 0
2738 || vrp_val_is_min (vr1
.min
))
2740 set_value_range_to_varying (vr
);
2744 /* Compute MAX <|vr1.min|, |vr1.max|> - 1. */
2745 max
= fold_unary_to_constant (ABS_EXPR
, expr_type
, vr1
.min
);
2746 if (tree_int_cst_lt (max
, vr1
.max
))
2748 max
= int_const_binop (MINUS_EXPR
, max
, integer_one_node
);
2749 /* If the dividend is non-negative the modulus will be
2750 non-negative as well. */
2751 if (TYPE_UNSIGNED (expr_type
)
2752 || value_range_nonnegative_p (&vr0
))
2753 min
= build_int_cst (TREE_TYPE (max
), 0);
2755 min
= fold_unary_to_constant (NEGATE_EXPR
, expr_type
, max
);
2757 else if (code
== BIT_AND_EXPR
|| code
== BIT_IOR_EXPR
|| code
== BIT_XOR_EXPR
)
2759 bool int_cst_range0
, int_cst_range1
;
2760 double_int may_be_nonzero0
, may_be_nonzero1
;
2761 double_int must_be_nonzero0
, must_be_nonzero1
;
2763 int_cst_range0
= zero_nonzero_bits_from_vr (&vr0
, &may_be_nonzero0
,
2765 int_cst_range1
= zero_nonzero_bits_from_vr (&vr1
, &may_be_nonzero1
,
2769 if (code
== BIT_AND_EXPR
)
2772 min
= double_int_to_tree (expr_type
,
2773 double_int_and (must_be_nonzero0
,
2775 dmax
= double_int_and (may_be_nonzero0
, may_be_nonzero1
);
2776 /* If both input ranges contain only negative values we can
2777 truncate the result range maximum to the minimum of the
2778 input range maxima. */
2779 if (int_cst_range0
&& int_cst_range1
2780 && tree_int_cst_sgn (vr0
.max
) < 0
2781 && tree_int_cst_sgn (vr1
.max
) < 0)
2783 dmax
= double_int_min (dmax
, tree_to_double_int (vr0
.max
),
2784 TYPE_UNSIGNED (expr_type
));
2785 dmax
= double_int_min (dmax
, tree_to_double_int (vr1
.max
),
2786 TYPE_UNSIGNED (expr_type
));
2788 /* If either input range contains only non-negative values
2789 we can truncate the result range maximum to the respective
2790 maximum of the input range. */
2791 if (int_cst_range0
&& tree_int_cst_sgn (vr0
.min
) >= 0)
2792 dmax
= double_int_min (dmax
, tree_to_double_int (vr0
.max
),
2793 TYPE_UNSIGNED (expr_type
));
2794 if (int_cst_range1
&& tree_int_cst_sgn (vr1
.min
) >= 0)
2795 dmax
= double_int_min (dmax
, tree_to_double_int (vr1
.max
),
2796 TYPE_UNSIGNED (expr_type
));
2797 max
= double_int_to_tree (expr_type
, dmax
);
2799 else if (code
== BIT_IOR_EXPR
)
2802 max
= double_int_to_tree (expr_type
,
2803 double_int_ior (may_be_nonzero0
,
2805 dmin
= double_int_ior (must_be_nonzero0
, must_be_nonzero1
);
2806 /* If the input ranges contain only positive values we can
2807 truncate the minimum of the result range to the maximum
2808 of the input range minima. */
2809 if (int_cst_range0
&& int_cst_range1
2810 && tree_int_cst_sgn (vr0
.min
) >= 0
2811 && tree_int_cst_sgn (vr1
.min
) >= 0)
2813 dmin
= double_int_max (dmin
, tree_to_double_int (vr0
.min
),
2814 TYPE_UNSIGNED (expr_type
));
2815 dmin
= double_int_max (dmin
, tree_to_double_int (vr1
.min
),
2816 TYPE_UNSIGNED (expr_type
));
2818 /* If either input range contains only negative values
2819 we can truncate the minimum of the result range to the
2820 respective minimum range. */
2821 if (int_cst_range0
&& tree_int_cst_sgn (vr0
.max
) < 0)
2822 dmin
= double_int_max (dmin
, tree_to_double_int (vr0
.min
),
2823 TYPE_UNSIGNED (expr_type
));
2824 if (int_cst_range1
&& tree_int_cst_sgn (vr1
.max
) < 0)
2825 dmin
= double_int_max (dmin
, tree_to_double_int (vr1
.min
),
2826 TYPE_UNSIGNED (expr_type
));
2827 min
= double_int_to_tree (expr_type
, dmin
);
2829 else if (code
== BIT_XOR_EXPR
)
2831 double_int result_zero_bits
, result_one_bits
;
2833 = double_int_ior (double_int_and (must_be_nonzero0
,
2836 (double_int_ior (may_be_nonzero0
,
2839 = double_int_ior (double_int_and
2841 double_int_not (may_be_nonzero1
)),
2844 double_int_not (may_be_nonzero0
)));
2845 max
= double_int_to_tree (expr_type
,
2846 double_int_not (result_zero_bits
));
2847 min
= double_int_to_tree (expr_type
, result_one_bits
);
2848 /* If the range has all positive or all negative values the
2849 result is better than VARYING. */
2850 if (tree_int_cst_sgn (min
) < 0
2851 || tree_int_cst_sgn (max
) >= 0)
2854 max
= min
= NULL_TREE
;
2860 /* If either MIN or MAX overflowed, then set the resulting range to
2861 VARYING. But we do accept an overflow infinity
2863 if (min
== NULL_TREE
2864 || !is_gimple_min_invariant (min
)
2865 || (TREE_OVERFLOW (min
) && !is_overflow_infinity (min
))
2867 || !is_gimple_min_invariant (max
)
2868 || (TREE_OVERFLOW (max
) && !is_overflow_infinity (max
)))
2870 set_value_range_to_varying (vr
);
2876 2) [-INF, +-INF(OVF)]
2877 3) [+-INF(OVF), +INF]
2878 4) [+-INF(OVF), +-INF(OVF)]
2879 We learn nothing when we have INF and INF(OVF) on both sides.
2880 Note that we do accept [-INF, -INF] and [+INF, +INF] without
2882 if ((vrp_val_is_min (min
) || is_overflow_infinity (min
))
2883 && (vrp_val_is_max (max
) || is_overflow_infinity (max
)))
2885 set_value_range_to_varying (vr
);
2889 cmp
= compare_values (min
, max
);
2890 if (cmp
== -2 || cmp
== 1)
2892 /* If the new range has its limits swapped around (MIN > MAX),
2893 then the operation caused one of them to wrap around, mark
2894 the new range VARYING. */
2895 set_value_range_to_varying (vr
);
2898 set_value_range (vr
, type
, min
, max
, NULL
);
2901 /* Extract range information from a binary expression OP0 CODE OP1 based on
2902 the ranges of each of its operands with resulting type EXPR_TYPE.
2903 The resulting range is stored in *VR. */
2906 extract_range_from_binary_expr (value_range_t
*vr
,
2907 enum tree_code code
,
2908 tree expr_type
, tree op0
, tree op1
)
2910 value_range_t vr0
= VR_INITIALIZER
;
2911 value_range_t vr1
= VR_INITIALIZER
;
2913 /* Get value ranges for each operand. For constant operands, create
2914 a new value range with the operand to simplify processing. */
2915 if (TREE_CODE (op0
) == SSA_NAME
)
2916 vr0
= *(get_value_range (op0
));
2917 else if (is_gimple_min_invariant (op0
))
2918 set_value_range_to_value (&vr0
, op0
, NULL
);
2920 set_value_range_to_varying (&vr0
);
2922 if (TREE_CODE (op1
) == SSA_NAME
)
2923 vr1
= *(get_value_range (op1
));
2924 else if (is_gimple_min_invariant (op1
))
2925 set_value_range_to_value (&vr1
, op1
, NULL
);
2927 set_value_range_to_varying (&vr1
);
2929 extract_range_from_binary_expr_1 (vr
, code
, expr_type
, &vr0
, &vr1
);
2932 /* Extract range information from a unary operation CODE based on
2933 the range of its operand *VR0 with type OP0_TYPE with resulting type TYPE.
2934 The The resulting range is stored in *VR. */
2937 extract_range_from_unary_expr_1 (value_range_t
*vr
,
2938 enum tree_code code
, tree type
,
2939 value_range_t
*vr0_
, tree op0_type
)
2941 value_range_t vr0
= *vr0_
, vrtem0
= VR_INITIALIZER
, vrtem1
= VR_INITIALIZER
;
2943 /* VRP only operates on integral and pointer types. */
2944 if (!(INTEGRAL_TYPE_P (op0_type
)
2945 || POINTER_TYPE_P (op0_type
))
2946 || !(INTEGRAL_TYPE_P (type
)
2947 || POINTER_TYPE_P (type
)))
2949 set_value_range_to_varying (vr
);
2953 /* If VR0 is UNDEFINED, so is the result. */
2954 if (vr0
.type
== VR_UNDEFINED
)
2956 set_value_range_to_undefined (vr
);
2960 /* Handle operations that we express in terms of others. */
2961 if (code
== PAREN_EXPR
)
2963 /* PAREN_EXPR is a simple copy. */
2964 copy_value_range (vr
, &vr0
);
2967 else if (code
== NEGATE_EXPR
)
2969 /* -X is simply 0 - X, so re-use existing code that also handles
2970 anti-ranges fine. */
2971 value_range_t zero
= VR_INITIALIZER
;
2972 set_value_range_to_value (&zero
, build_int_cst (type
, 0), NULL
);
2973 extract_range_from_binary_expr_1 (vr
, MINUS_EXPR
, type
, &zero
, &vr0
);
2976 else if (code
== BIT_NOT_EXPR
)
2978 /* ~X is simply -1 - X, so re-use existing code that also handles
2979 anti-ranges fine. */
2980 value_range_t minusone
= VR_INITIALIZER
;
2981 set_value_range_to_value (&minusone
, build_int_cst (type
, -1), NULL
);
2982 extract_range_from_binary_expr_1 (vr
, MINUS_EXPR
,
2983 type
, &minusone
, &vr0
);
2987 /* Now canonicalize anti-ranges to ranges when they are not symbolic
2988 and express op ~[] as (op []') U (op []''). */
2989 if (vr0
.type
== VR_ANTI_RANGE
2990 && ranges_from_anti_range (&vr0
, &vrtem0
, &vrtem1
))
2992 extract_range_from_unary_expr_1 (vr
, code
, type
, &vrtem0
, op0_type
);
2993 if (vrtem1
.type
!= VR_UNDEFINED
)
2995 value_range_t vrres
= VR_INITIALIZER
;
2996 extract_range_from_unary_expr_1 (&vrres
, code
, type
,
2998 vrp_meet (vr
, &vrres
);
3003 if (CONVERT_EXPR_CODE_P (code
))
3005 tree inner_type
= op0_type
;
3006 tree outer_type
= type
;
3008 /* If the expression evaluates to a pointer, we are only interested in
3009 determining if it evaluates to NULL [0, 0] or non-NULL (~[0, 0]). */
3010 if (POINTER_TYPE_P (type
))
3012 if (range_is_nonnull (&vr0
))
3013 set_value_range_to_nonnull (vr
, type
);
3014 else if (range_is_null (&vr0
))
3015 set_value_range_to_null (vr
, type
);
3017 set_value_range_to_varying (vr
);
3021 /* If VR0 is varying and we increase the type precision, assume
3022 a full range for the following transformation. */
3023 if (vr0
.type
== VR_VARYING
3024 && INTEGRAL_TYPE_P (inner_type
)
3025 && TYPE_PRECISION (inner_type
) < TYPE_PRECISION (outer_type
))
3027 vr0
.type
= VR_RANGE
;
3028 vr0
.min
= TYPE_MIN_VALUE (inner_type
);
3029 vr0
.max
= TYPE_MAX_VALUE (inner_type
);
3032 /* If VR0 is a constant range or anti-range and the conversion is
3033 not truncating we can convert the min and max values and
3034 canonicalize the resulting range. Otherwise we can do the
3035 conversion if the size of the range is less than what the
3036 precision of the target type can represent and the range is
3037 not an anti-range. */
3038 if ((vr0
.type
== VR_RANGE
3039 || vr0
.type
== VR_ANTI_RANGE
)
3040 && TREE_CODE (vr0
.min
) == INTEGER_CST
3041 && TREE_CODE (vr0
.max
) == INTEGER_CST
3042 && (!is_overflow_infinity (vr0
.min
)
3043 || (vr0
.type
== VR_RANGE
3044 && TYPE_PRECISION (outer_type
) > TYPE_PRECISION (inner_type
)
3045 && needs_overflow_infinity (outer_type
)
3046 && supports_overflow_infinity (outer_type
)))
3047 && (!is_overflow_infinity (vr0
.max
)
3048 || (vr0
.type
== VR_RANGE
3049 && TYPE_PRECISION (outer_type
) > TYPE_PRECISION (inner_type
)
3050 && needs_overflow_infinity (outer_type
)
3051 && supports_overflow_infinity (outer_type
)))
3052 && (TYPE_PRECISION (outer_type
) >= TYPE_PRECISION (inner_type
)
3053 || (vr0
.type
== VR_RANGE
3054 && integer_zerop (int_const_binop (RSHIFT_EXPR
,
3055 int_const_binop (MINUS_EXPR
, vr0
.max
, vr0
.min
),
3056 size_int (TYPE_PRECISION (outer_type
)))))))
3058 tree new_min
, new_max
;
3059 if (is_overflow_infinity (vr0
.min
))
3060 new_min
= negative_overflow_infinity (outer_type
);
3062 new_min
= force_fit_type_double (outer_type
,
3063 tree_to_double_int (vr0
.min
),
3065 if (is_overflow_infinity (vr0
.max
))
3066 new_max
= positive_overflow_infinity (outer_type
);
3068 new_max
= force_fit_type_double (outer_type
,
3069 tree_to_double_int (vr0
.max
),
3071 set_and_canonicalize_value_range (vr
, vr0
.type
,
3072 new_min
, new_max
, NULL
);
3076 set_value_range_to_varying (vr
);
3079 else if (code
== ABS_EXPR
)
3084 /* Pass through vr0 in the easy cases. */
3085 if (TYPE_UNSIGNED (type
)
3086 || value_range_nonnegative_p (&vr0
))
3088 copy_value_range (vr
, &vr0
);
3092 /* For the remaining varying or symbolic ranges we can't do anything
3094 if (vr0
.type
== VR_VARYING
3095 || symbolic_range_p (&vr0
))
3097 set_value_range_to_varying (vr
);
3101 /* -TYPE_MIN_VALUE = TYPE_MIN_VALUE with flag_wrapv so we can't get a
3103 if (!TYPE_OVERFLOW_UNDEFINED (type
)
3104 && ((vr0
.type
== VR_RANGE
3105 && vrp_val_is_min (vr0
.min
))
3106 || (vr0
.type
== VR_ANTI_RANGE
3107 && !vrp_val_is_min (vr0
.min
))))
3109 set_value_range_to_varying (vr
);
3113 /* ABS_EXPR may flip the range around, if the original range
3114 included negative values. */
3115 if (is_overflow_infinity (vr0
.min
))
3116 min
= positive_overflow_infinity (type
);
3117 else if (!vrp_val_is_min (vr0
.min
))
3118 min
= fold_unary_to_constant (code
, type
, vr0
.min
);
3119 else if (!needs_overflow_infinity (type
))
3120 min
= TYPE_MAX_VALUE (type
);
3121 else if (supports_overflow_infinity (type
))
3122 min
= positive_overflow_infinity (type
);
3125 set_value_range_to_varying (vr
);
3129 if (is_overflow_infinity (vr0
.max
))
3130 max
= positive_overflow_infinity (type
);
3131 else if (!vrp_val_is_min (vr0
.max
))
3132 max
= fold_unary_to_constant (code
, type
, vr0
.max
);
3133 else if (!needs_overflow_infinity (type
))
3134 max
= TYPE_MAX_VALUE (type
);
3135 else if (supports_overflow_infinity (type
)
3136 /* We shouldn't generate [+INF, +INF] as set_value_range
3137 doesn't like this and ICEs. */
3138 && !is_positive_overflow_infinity (min
))
3139 max
= positive_overflow_infinity (type
);
3142 set_value_range_to_varying (vr
);
3146 cmp
= compare_values (min
, max
);
3148 /* If a VR_ANTI_RANGEs contains zero, then we have
3149 ~[-INF, min(MIN, MAX)]. */
3150 if (vr0
.type
== VR_ANTI_RANGE
)
3152 if (range_includes_zero_p (vr0
.min
, vr0
.max
) == 1)
3154 /* Take the lower of the two values. */
3158 /* Create ~[-INF, min (abs(MIN), abs(MAX))]
3159 or ~[-INF + 1, min (abs(MIN), abs(MAX))] when
3160 flag_wrapv is set and the original anti-range doesn't include
3161 TYPE_MIN_VALUE, remember -TYPE_MIN_VALUE = TYPE_MIN_VALUE. */
3162 if (TYPE_OVERFLOW_WRAPS (type
))
3164 tree type_min_value
= TYPE_MIN_VALUE (type
);
3166 min
= (vr0
.min
!= type_min_value
3167 ? int_const_binop (PLUS_EXPR
, type_min_value
,
3173 if (overflow_infinity_range_p (&vr0
))
3174 min
= negative_overflow_infinity (type
);
3176 min
= TYPE_MIN_VALUE (type
);
3181 /* All else has failed, so create the range [0, INF], even for
3182 flag_wrapv since TYPE_MIN_VALUE is in the original
3184 vr0
.type
= VR_RANGE
;
3185 min
= build_int_cst (type
, 0);
3186 if (needs_overflow_infinity (type
))
3188 if (supports_overflow_infinity (type
))
3189 max
= positive_overflow_infinity (type
);
3192 set_value_range_to_varying (vr
);
3197 max
= TYPE_MAX_VALUE (type
);
3201 /* If the range contains zero then we know that the minimum value in the
3202 range will be zero. */
3203 else if (range_includes_zero_p (vr0
.min
, vr0
.max
) == 1)
3207 min
= build_int_cst (type
, 0);
3211 /* If the range was reversed, swap MIN and MAX. */
3220 cmp
= compare_values (min
, max
);
3221 if (cmp
== -2 || cmp
== 1)
3223 /* If the new range has its limits swapped around (MIN > MAX),
3224 then the operation caused one of them to wrap around, mark
3225 the new range VARYING. */
3226 set_value_range_to_varying (vr
);
3229 set_value_range (vr
, vr0
.type
, min
, max
, NULL
);
3233 /* For unhandled operations fall back to varying. */
3234 set_value_range_to_varying (vr
);
3239 /* Extract range information from a unary expression CODE OP0 based on
3240 the range of its operand with resulting type TYPE.
3241 The resulting range is stored in *VR. */
3244 extract_range_from_unary_expr (value_range_t
*vr
, enum tree_code code
,
3245 tree type
, tree op0
)
3247 value_range_t vr0
= VR_INITIALIZER
;
3249 /* Get value ranges for the operand. For constant operands, create
3250 a new value range with the operand to simplify processing. */
3251 if (TREE_CODE (op0
) == SSA_NAME
)
3252 vr0
= *(get_value_range (op0
));
3253 else if (is_gimple_min_invariant (op0
))
3254 set_value_range_to_value (&vr0
, op0
, NULL
);
3256 set_value_range_to_varying (&vr0
);
3258 extract_range_from_unary_expr_1 (vr
, code
, type
, &vr0
, TREE_TYPE (op0
));
3262 /* Extract range information from a conditional expression STMT based on
3263 the ranges of each of its operands and the expression code. */
3266 extract_range_from_cond_expr (value_range_t
*vr
, gimple stmt
)
3269 value_range_t vr0
= VR_INITIALIZER
;
3270 value_range_t vr1
= VR_INITIALIZER
;
3272 /* Get value ranges for each operand. For constant operands, create
3273 a new value range with the operand to simplify processing. */
3274 op0
= gimple_assign_rhs2 (stmt
);
3275 if (TREE_CODE (op0
) == SSA_NAME
)
3276 vr0
= *(get_value_range (op0
));
3277 else if (is_gimple_min_invariant (op0
))
3278 set_value_range_to_value (&vr0
, op0
, NULL
);
3280 set_value_range_to_varying (&vr0
);
3282 op1
= gimple_assign_rhs3 (stmt
);
3283 if (TREE_CODE (op1
) == SSA_NAME
)
3284 vr1
= *(get_value_range (op1
));
3285 else if (is_gimple_min_invariant (op1
))
3286 set_value_range_to_value (&vr1
, op1
, NULL
);
3288 set_value_range_to_varying (&vr1
);
3290 /* The resulting value range is the union of the operand ranges */
3291 copy_value_range (vr
, &vr0
);
3292 vrp_meet (vr
, &vr1
);
3296 /* Extract range information from a comparison expression EXPR based
3297 on the range of its operand and the expression code. */
3300 extract_range_from_comparison (value_range_t
*vr
, enum tree_code code
,
3301 tree type
, tree op0
, tree op1
)
3306 val
= vrp_evaluate_conditional_warnv_with_ops (code
, op0
, op1
, false, &sop
,
3309 /* A disadvantage of using a special infinity as an overflow
3310 representation is that we lose the ability to record overflow
3311 when we don't have an infinity. So we have to ignore a result
3312 which relies on overflow. */
3314 if (val
&& !is_overflow_infinity (val
) && !sop
)
3316 /* Since this expression was found on the RHS of an assignment,
3317 its type may be different from _Bool. Convert VAL to EXPR's
3319 val
= fold_convert (type
, val
);
3320 if (is_gimple_min_invariant (val
))
3321 set_value_range_to_value (vr
, val
, vr
->equiv
);
3323 set_value_range (vr
, VR_RANGE
, val
, val
, vr
->equiv
);
3326 /* The result of a comparison is always true or false. */
3327 set_value_range_to_truthvalue (vr
, type
);
3330 /* Try to derive a nonnegative or nonzero range out of STMT relying
3331 primarily on generic routines in fold in conjunction with range data.
3332 Store the result in *VR */
3335 extract_range_basic (value_range_t
*vr
, gimple stmt
)
3338 tree type
= gimple_expr_type (stmt
);
3340 if (INTEGRAL_TYPE_P (type
)
3341 && gimple_stmt_nonnegative_warnv_p (stmt
, &sop
))
3342 set_value_range_to_nonnegative (vr
, type
,
3343 sop
|| stmt_overflow_infinity (stmt
));
3344 else if (vrp_stmt_computes_nonzero (stmt
, &sop
)
3346 set_value_range_to_nonnull (vr
, type
);
3348 set_value_range_to_varying (vr
);
3352 /* Try to compute a useful range out of assignment STMT and store it
3356 extract_range_from_assignment (value_range_t
*vr
, gimple stmt
)
3358 enum tree_code code
= gimple_assign_rhs_code (stmt
);
3360 if (code
== ASSERT_EXPR
)
3361 extract_range_from_assert (vr
, gimple_assign_rhs1 (stmt
));
3362 else if (code
== SSA_NAME
)
3363 extract_range_from_ssa_name (vr
, gimple_assign_rhs1 (stmt
));
3364 else if (TREE_CODE_CLASS (code
) == tcc_binary
)
3365 extract_range_from_binary_expr (vr
, gimple_assign_rhs_code (stmt
),
3366 gimple_expr_type (stmt
),
3367 gimple_assign_rhs1 (stmt
),
3368 gimple_assign_rhs2 (stmt
));
3369 else if (TREE_CODE_CLASS (code
) == tcc_unary
)
3370 extract_range_from_unary_expr (vr
, gimple_assign_rhs_code (stmt
),
3371 gimple_expr_type (stmt
),
3372 gimple_assign_rhs1 (stmt
));
3373 else if (code
== COND_EXPR
)
3374 extract_range_from_cond_expr (vr
, stmt
);
3375 else if (TREE_CODE_CLASS (code
) == tcc_comparison
)
3376 extract_range_from_comparison (vr
, gimple_assign_rhs_code (stmt
),
3377 gimple_expr_type (stmt
),
3378 gimple_assign_rhs1 (stmt
),
3379 gimple_assign_rhs2 (stmt
));
3380 else if (get_gimple_rhs_class (code
) == GIMPLE_SINGLE_RHS
3381 && is_gimple_min_invariant (gimple_assign_rhs1 (stmt
)))
3382 set_value_range_to_value (vr
, gimple_assign_rhs1 (stmt
), NULL
);
3384 set_value_range_to_varying (vr
);
3386 if (vr
->type
== VR_VARYING
)
3387 extract_range_basic (vr
, stmt
);
3390 /* Given a range VR, a LOOP and a variable VAR, determine whether it
3391 would be profitable to adjust VR using scalar evolution information
3392 for VAR. If so, update VR with the new limits. */
3395 adjust_range_with_scev (value_range_t
*vr
, struct loop
*loop
,
3396 gimple stmt
, tree var
)
3398 tree init
, step
, chrec
, tmin
, tmax
, min
, max
, type
, tem
;
3399 enum ev_direction dir
;
3401 /* TODO. Don't adjust anti-ranges. An anti-range may provide
3402 better opportunities than a regular range, but I'm not sure. */
3403 if (vr
->type
== VR_ANTI_RANGE
)
3406 chrec
= instantiate_parameters (loop
, analyze_scalar_evolution (loop
, var
));
3408 /* Like in PR19590, scev can return a constant function. */
3409 if (is_gimple_min_invariant (chrec
))
3411 set_value_range_to_value (vr
, chrec
, vr
->equiv
);
3415 if (TREE_CODE (chrec
) != POLYNOMIAL_CHREC
)
3418 init
= initial_condition_in_loop_num (chrec
, loop
->num
);
3419 tem
= op_with_constant_singleton_value_range (init
);
3422 step
= evolution_part_in_loop_num (chrec
, loop
->num
);
3423 tem
= op_with_constant_singleton_value_range (step
);
3427 /* If STEP is symbolic, we can't know whether INIT will be the
3428 minimum or maximum value in the range. Also, unless INIT is
3429 a simple expression, compare_values and possibly other functions
3430 in tree-vrp won't be able to handle it. */
3431 if (step
== NULL_TREE
3432 || !is_gimple_min_invariant (step
)
3433 || !valid_value_p (init
))
3436 dir
= scev_direction (chrec
);
3437 if (/* Do not adjust ranges if we do not know whether the iv increases
3438 or decreases, ... */
3439 dir
== EV_DIR_UNKNOWN
3440 /* ... or if it may wrap. */
3441 || scev_probably_wraps_p (init
, step
, stmt
, get_chrec_loop (chrec
),
3445 /* We use TYPE_MIN_VALUE and TYPE_MAX_VALUE here instead of
3446 negative_overflow_infinity and positive_overflow_infinity,
3447 because we have concluded that the loop probably does not
3450 type
= TREE_TYPE (var
);
3451 if (POINTER_TYPE_P (type
) || !TYPE_MIN_VALUE (type
))
3452 tmin
= lower_bound_in_type (type
, type
);
3454 tmin
= TYPE_MIN_VALUE (type
);
3455 if (POINTER_TYPE_P (type
) || !TYPE_MAX_VALUE (type
))
3456 tmax
= upper_bound_in_type (type
, type
);
3458 tmax
= TYPE_MAX_VALUE (type
);
3460 /* Try to use estimated number of iterations for the loop to constrain the
3461 final value in the evolution. */
3462 if (TREE_CODE (step
) == INTEGER_CST
3463 && is_gimple_val (init
)
3464 && (TREE_CODE (init
) != SSA_NAME
3465 || get_value_range (init
)->type
== VR_RANGE
))
3469 /* We are only entering here for loop header PHI nodes, so using
3470 the number of latch executions is the correct thing to use. */
3471 if (max_loop_iterations (loop
, &nit
))
3473 value_range_t maxvr
= VR_INITIALIZER
;
3475 bool unsigned_p
= TYPE_UNSIGNED (TREE_TYPE (step
));
3478 dtmp
= double_int_mul_with_sign (tree_to_double_int (step
), nit
,
3479 unsigned_p
, &overflow
);
3480 /* If the multiplication overflowed we can't do a meaningful
3481 adjustment. Likewise if the result doesn't fit in the type
3482 of the induction variable. For a signed type we have to
3483 check whether the result has the expected signedness which
3484 is that of the step as number of iterations is unsigned. */
3486 && double_int_fits_to_tree_p (TREE_TYPE (init
), dtmp
)
3488 || ((dtmp
.high
^ TREE_INT_CST_HIGH (step
)) >= 0)))
3490 tem
= double_int_to_tree (TREE_TYPE (init
), dtmp
);
3491 extract_range_from_binary_expr (&maxvr
, PLUS_EXPR
,
3492 TREE_TYPE (init
), init
, tem
);
3493 /* Likewise if the addition did. */
3494 if (maxvr
.type
== VR_RANGE
)
3503 if (vr
->type
== VR_VARYING
|| vr
->type
== VR_UNDEFINED
)
3508 /* For VARYING or UNDEFINED ranges, just about anything we get
3509 from scalar evolutions should be better. */
3511 if (dir
== EV_DIR_DECREASES
)
3516 /* If we would create an invalid range, then just assume we
3517 know absolutely nothing. This may be over-conservative,
3518 but it's clearly safe, and should happen only in unreachable
3519 parts of code, or for invalid programs. */
3520 if (compare_values (min
, max
) == 1)
3523 set_value_range (vr
, VR_RANGE
, min
, max
, vr
->equiv
);
3525 else if (vr
->type
== VR_RANGE
)
3530 if (dir
== EV_DIR_DECREASES
)
3532 /* INIT is the maximum value. If INIT is lower than VR->MAX
3533 but no smaller than VR->MIN, set VR->MAX to INIT. */
3534 if (compare_values (init
, max
) == -1)
3537 /* According to the loop information, the variable does not
3538 overflow. If we think it does, probably because of an
3539 overflow due to arithmetic on a different INF value,
3541 if (is_negative_overflow_infinity (min
)
3542 || compare_values (min
, tmin
) == -1)
3548 /* If INIT is bigger than VR->MIN, set VR->MIN to INIT. */
3549 if (compare_values (init
, min
) == 1)
3552 if (is_positive_overflow_infinity (max
)
3553 || compare_values (tmax
, max
) == -1)
3557 /* If we just created an invalid range with the minimum
3558 greater than the maximum, we fail conservatively.
3559 This should happen only in unreachable
3560 parts of code, or for invalid programs. */
3561 if (compare_values (min
, max
) == 1)
3564 set_value_range (vr
, VR_RANGE
, min
, max
, vr
->equiv
);
3568 /* Return true if VAR may overflow at STMT. This checks any available
3569 loop information to see if we can determine that VAR does not
3573 vrp_var_may_overflow (tree var
, gimple stmt
)
3576 tree chrec
, init
, step
;
3578 if (current_loops
== NULL
)
3581 l
= loop_containing_stmt (stmt
);
3586 chrec
= instantiate_parameters (l
, analyze_scalar_evolution (l
, var
));
3587 if (TREE_CODE (chrec
) != POLYNOMIAL_CHREC
)
3590 init
= initial_condition_in_loop_num (chrec
, l
->num
);
3591 step
= evolution_part_in_loop_num (chrec
, l
->num
);
3593 if (step
== NULL_TREE
3594 || !is_gimple_min_invariant (step
)
3595 || !valid_value_p (init
))
3598 /* If we get here, we know something useful about VAR based on the
3599 loop information. If it wraps, it may overflow. */
3601 if (scev_probably_wraps_p (init
, step
, stmt
, get_chrec_loop (chrec
),
3605 if (dump_file
&& (dump_flags
& TDF_DETAILS
) != 0)
3607 print_generic_expr (dump_file
, var
, 0);
3608 fprintf (dump_file
, ": loop information indicates does not overflow\n");
3615 /* Given two numeric value ranges VR0, VR1 and a comparison code COMP:
3617 - Return BOOLEAN_TRUE_NODE if VR0 COMP VR1 always returns true for
3618 all the values in the ranges.
3620 - Return BOOLEAN_FALSE_NODE if the comparison always returns false.
3622 - Return NULL_TREE if it is not always possible to determine the
3623 value of the comparison.
3625 Also set *STRICT_OVERFLOW_P to indicate whether a range with an
3626 overflow infinity was used in the test. */
3630 compare_ranges (enum tree_code comp
, value_range_t
*vr0
, value_range_t
*vr1
,
3631 bool *strict_overflow_p
)
3633 /* VARYING or UNDEFINED ranges cannot be compared. */
3634 if (vr0
->type
== VR_VARYING
3635 || vr0
->type
== VR_UNDEFINED
3636 || vr1
->type
== VR_VARYING
3637 || vr1
->type
== VR_UNDEFINED
)
3640 /* Anti-ranges need to be handled separately. */
3641 if (vr0
->type
== VR_ANTI_RANGE
|| vr1
->type
== VR_ANTI_RANGE
)
3643 /* If both are anti-ranges, then we cannot compute any
3645 if (vr0
->type
== VR_ANTI_RANGE
&& vr1
->type
== VR_ANTI_RANGE
)
3648 /* These comparisons are never statically computable. */
3655 /* Equality can be computed only between a range and an
3656 anti-range. ~[VAL1, VAL2] == [VAL1, VAL2] is always false. */
3657 if (vr0
->type
== VR_RANGE
)
3659 /* To simplify processing, make VR0 the anti-range. */
3660 value_range_t
*tmp
= vr0
;
3665 gcc_assert (comp
== NE_EXPR
|| comp
== EQ_EXPR
);
3667 if (compare_values_warnv (vr0
->min
, vr1
->min
, strict_overflow_p
) == 0
3668 && compare_values_warnv (vr0
->max
, vr1
->max
, strict_overflow_p
) == 0)
3669 return (comp
== NE_EXPR
) ? boolean_true_node
: boolean_false_node
;
3674 if (!usable_range_p (vr0
, strict_overflow_p
)
3675 || !usable_range_p (vr1
, strict_overflow_p
))
3678 /* Simplify processing. If COMP is GT_EXPR or GE_EXPR, switch the
3679 operands around and change the comparison code. */
3680 if (comp
== GT_EXPR
|| comp
== GE_EXPR
)
3683 comp
= (comp
== GT_EXPR
) ? LT_EXPR
: LE_EXPR
;
3689 if (comp
== EQ_EXPR
)
3691 /* Equality may only be computed if both ranges represent
3692 exactly one value. */
3693 if (compare_values_warnv (vr0
->min
, vr0
->max
, strict_overflow_p
) == 0
3694 && compare_values_warnv (vr1
->min
, vr1
->max
, strict_overflow_p
) == 0)
3696 int cmp_min
= compare_values_warnv (vr0
->min
, vr1
->min
,
3698 int cmp_max
= compare_values_warnv (vr0
->max
, vr1
->max
,
3700 if (cmp_min
== 0 && cmp_max
== 0)
3701 return boolean_true_node
;
3702 else if (cmp_min
!= -2 && cmp_max
!= -2)
3703 return boolean_false_node
;
3705 /* If [V0_MIN, V1_MAX] < [V1_MIN, V1_MAX] then V0 != V1. */
3706 else if (compare_values_warnv (vr0
->min
, vr1
->max
,
3707 strict_overflow_p
) == 1
3708 || compare_values_warnv (vr1
->min
, vr0
->max
,
3709 strict_overflow_p
) == 1)
3710 return boolean_false_node
;
3714 else if (comp
== NE_EXPR
)
3718 /* If VR0 is completely to the left or completely to the right
3719 of VR1, they are always different. Notice that we need to
3720 make sure that both comparisons yield similar results to
3721 avoid comparing values that cannot be compared at
3723 cmp1
= compare_values_warnv (vr0
->max
, vr1
->min
, strict_overflow_p
);
3724 cmp2
= compare_values_warnv (vr0
->min
, vr1
->max
, strict_overflow_p
);
3725 if ((cmp1
== -1 && cmp2
== -1) || (cmp1
== 1 && cmp2
== 1))
3726 return boolean_true_node
;
3728 /* If VR0 and VR1 represent a single value and are identical,
3730 else if (compare_values_warnv (vr0
->min
, vr0
->max
,
3731 strict_overflow_p
) == 0
3732 && compare_values_warnv (vr1
->min
, vr1
->max
,
3733 strict_overflow_p
) == 0
3734 && compare_values_warnv (vr0
->min
, vr1
->min
,
3735 strict_overflow_p
) == 0
3736 && compare_values_warnv (vr0
->max
, vr1
->max
,
3737 strict_overflow_p
) == 0)
3738 return boolean_false_node
;
3740 /* Otherwise, they may or may not be different. */
3744 else if (comp
== LT_EXPR
|| comp
== LE_EXPR
)
3748 /* If VR0 is to the left of VR1, return true. */
3749 tst
= compare_values_warnv (vr0
->max
, vr1
->min
, strict_overflow_p
);
3750 if ((comp
== LT_EXPR
&& tst
== -1)
3751 || (comp
== LE_EXPR
&& (tst
== -1 || tst
== 0)))
3753 if (overflow_infinity_range_p (vr0
)
3754 || overflow_infinity_range_p (vr1
))
3755 *strict_overflow_p
= true;
3756 return boolean_true_node
;
3759 /* If VR0 is to the right of VR1, return false. */
3760 tst
= compare_values_warnv (vr0
->min
, vr1
->max
, strict_overflow_p
);
3761 if ((comp
== LT_EXPR
&& (tst
== 0 || tst
== 1))
3762 || (comp
== LE_EXPR
&& tst
== 1))
3764 if (overflow_infinity_range_p (vr0
)
3765 || overflow_infinity_range_p (vr1
))
3766 *strict_overflow_p
= true;
3767 return boolean_false_node
;
3770 /* Otherwise, we don't know. */
3778 /* Given a value range VR, a value VAL and a comparison code COMP, return
3779 BOOLEAN_TRUE_NODE if VR COMP VAL always returns true for all the
3780 values in VR. Return BOOLEAN_FALSE_NODE if the comparison
3781 always returns false. Return NULL_TREE if it is not always
3782 possible to determine the value of the comparison. Also set
3783 *STRICT_OVERFLOW_P to indicate whether a range with an overflow
3784 infinity was used in the test. */
3787 compare_range_with_value (enum tree_code comp
, value_range_t
*vr
, tree val
,
3788 bool *strict_overflow_p
)
3790 if (vr
->type
== VR_VARYING
|| vr
->type
== VR_UNDEFINED
)
3793 /* Anti-ranges need to be handled separately. */
3794 if (vr
->type
== VR_ANTI_RANGE
)
3796 /* For anti-ranges, the only predicates that we can compute at
3797 compile time are equality and inequality. */
3804 /* ~[VAL_1, VAL_2] OP VAL is known if VAL_1 <= VAL <= VAL_2. */
3805 if (value_inside_range (val
, vr
->min
, vr
->max
) == 1)
3806 return (comp
== NE_EXPR
) ? boolean_true_node
: boolean_false_node
;
3811 if (!usable_range_p (vr
, strict_overflow_p
))
3814 if (comp
== EQ_EXPR
)
3816 /* EQ_EXPR may only be computed if VR represents exactly
3818 if (compare_values_warnv (vr
->min
, vr
->max
, strict_overflow_p
) == 0)
3820 int cmp
= compare_values_warnv (vr
->min
, val
, strict_overflow_p
);
3822 return boolean_true_node
;
3823 else if (cmp
== -1 || cmp
== 1 || cmp
== 2)
3824 return boolean_false_node
;
3826 else if (compare_values_warnv (val
, vr
->min
, strict_overflow_p
) == -1
3827 || compare_values_warnv (vr
->max
, val
, strict_overflow_p
) == -1)
3828 return boolean_false_node
;
3832 else if (comp
== NE_EXPR
)
3834 /* If VAL is not inside VR, then they are always different. */
3835 if (compare_values_warnv (vr
->max
, val
, strict_overflow_p
) == -1
3836 || compare_values_warnv (vr
->min
, val
, strict_overflow_p
) == 1)
3837 return boolean_true_node
;
3839 /* If VR represents exactly one value equal to VAL, then return
3841 if (compare_values_warnv (vr
->min
, vr
->max
, strict_overflow_p
) == 0
3842 && compare_values_warnv (vr
->min
, val
, strict_overflow_p
) == 0)
3843 return boolean_false_node
;
3845 /* Otherwise, they may or may not be different. */
3848 else if (comp
== LT_EXPR
|| comp
== LE_EXPR
)
3852 /* If VR is to the left of VAL, return true. */
3853 tst
= compare_values_warnv (vr
->max
, val
, strict_overflow_p
);
3854 if ((comp
== LT_EXPR
&& tst
== -1)
3855 || (comp
== LE_EXPR
&& (tst
== -1 || tst
== 0)))
3857 if (overflow_infinity_range_p (vr
))
3858 *strict_overflow_p
= true;
3859 return boolean_true_node
;
3862 /* If VR is to the right of VAL, return false. */
3863 tst
= compare_values_warnv (vr
->min
, val
, strict_overflow_p
);
3864 if ((comp
== LT_EXPR
&& (tst
== 0 || tst
== 1))
3865 || (comp
== LE_EXPR
&& tst
== 1))
3867 if (overflow_infinity_range_p (vr
))
3868 *strict_overflow_p
= true;
3869 return boolean_false_node
;
3872 /* Otherwise, we don't know. */
3875 else if (comp
== GT_EXPR
|| comp
== GE_EXPR
)
3879 /* If VR is to the right of VAL, return true. */
3880 tst
= compare_values_warnv (vr
->min
, val
, strict_overflow_p
);
3881 if ((comp
== GT_EXPR
&& tst
== 1)
3882 || (comp
== GE_EXPR
&& (tst
== 0 || tst
== 1)))
3884 if (overflow_infinity_range_p (vr
))
3885 *strict_overflow_p
= true;
3886 return boolean_true_node
;
3889 /* If VR is to the left of VAL, return false. */
3890 tst
= compare_values_warnv (vr
->max
, val
, strict_overflow_p
);
3891 if ((comp
== GT_EXPR
&& (tst
== -1 || tst
== 0))
3892 || (comp
== GE_EXPR
&& tst
== -1))
3894 if (overflow_infinity_range_p (vr
))
3895 *strict_overflow_p
= true;
3896 return boolean_false_node
;
3899 /* Otherwise, we don't know. */
3907 /* Debugging dumps. */
3909 void dump_value_range (FILE *, value_range_t
*);
3910 void debug_value_range (value_range_t
*);
3911 void dump_all_value_ranges (FILE *);
3912 void debug_all_value_ranges (void);
3913 void dump_vr_equiv (FILE *, bitmap
);
3914 void debug_vr_equiv (bitmap
);
3917 /* Dump value range VR to FILE. */
3920 dump_value_range (FILE *file
, value_range_t
*vr
)
3923 fprintf (file
, "[]");
3924 else if (vr
->type
== VR_UNDEFINED
)
3925 fprintf (file
, "UNDEFINED");
3926 else if (vr
->type
== VR_RANGE
|| vr
->type
== VR_ANTI_RANGE
)
3928 tree type
= TREE_TYPE (vr
->min
);
3930 fprintf (file
, "%s[", (vr
->type
== VR_ANTI_RANGE
) ? "~" : "");
3932 if (is_negative_overflow_infinity (vr
->min
))
3933 fprintf (file
, "-INF(OVF)");
3934 else if (INTEGRAL_TYPE_P (type
)
3935 && !TYPE_UNSIGNED (type
)
3936 && vrp_val_is_min (vr
->min
))
3937 fprintf (file
, "-INF");
3939 print_generic_expr (file
, vr
->min
, 0);
3941 fprintf (file
, ", ");
3943 if (is_positive_overflow_infinity (vr
->max
))
3944 fprintf (file
, "+INF(OVF)");
3945 else if (INTEGRAL_TYPE_P (type
)
3946 && vrp_val_is_max (vr
->max
))
3947 fprintf (file
, "+INF");
3949 print_generic_expr (file
, vr
->max
, 0);
3951 fprintf (file
, "]");
3958 fprintf (file
, " EQUIVALENCES: { ");
3960 EXECUTE_IF_SET_IN_BITMAP (vr
->equiv
, 0, i
, bi
)
3962 print_generic_expr (file
, ssa_name (i
), 0);
3963 fprintf (file
, " ");
3967 fprintf (file
, "} (%u elements)", c
);
3970 else if (vr
->type
== VR_VARYING
)
3971 fprintf (file
, "VARYING");
3973 fprintf (file
, "INVALID RANGE");
3977 /* Dump value range VR to stderr. */
3980 debug_value_range (value_range_t
*vr
)
3982 dump_value_range (stderr
, vr
);
3983 fprintf (stderr
, "\n");
3987 /* Dump value ranges of all SSA_NAMEs to FILE. */
3990 dump_all_value_ranges (FILE *file
)
3994 for (i
= 0; i
< num_vr_values
; i
++)
3998 print_generic_expr (file
, ssa_name (i
), 0);
3999 fprintf (file
, ": ");
4000 dump_value_range (file
, vr_value
[i
]);
4001 fprintf (file
, "\n");
4005 fprintf (file
, "\n");
4009 /* Dump all value ranges to stderr. */
4012 debug_all_value_ranges (void)
4014 dump_all_value_ranges (stderr
);
4018 /* Given a COND_EXPR COND of the form 'V OP W', and an SSA name V,
4019 create a new SSA name N and return the assertion assignment
4020 'V = ASSERT_EXPR <V, V OP W>'. */
4023 build_assert_expr_for (tree cond
, tree v
)
4028 gcc_assert (TREE_CODE (v
) == SSA_NAME
);
4029 n
= duplicate_ssa_name (v
, NULL
);
4031 if (COMPARISON_CLASS_P (cond
))
4033 tree a
= build2 (ASSERT_EXPR
, TREE_TYPE (v
), v
, cond
);
4034 assertion
= gimple_build_assign (n
, a
);
4036 else if (TREE_CODE (cond
) == SSA_NAME
)
4038 /* Given V, build the assignment N = true. */
4039 gcc_assert (v
== cond
);
4040 assertion
= gimple_build_assign (n
, boolean_true_node
);
4045 SSA_NAME_DEF_STMT (n
) = assertion
;
4047 /* The new ASSERT_EXPR, creates a new SSA name that replaces the
4048 operand of the ASSERT_EXPR. Register the new name and the old one
4049 in the replacement table so that we can fix the SSA web after
4050 adding all the ASSERT_EXPRs. */
4051 register_new_name_mapping (n
, v
);
4057 /* Return false if EXPR is a predicate expression involving floating
4061 fp_predicate (gimple stmt
)
4063 GIMPLE_CHECK (stmt
, GIMPLE_COND
);
4065 return FLOAT_TYPE_P (TREE_TYPE (gimple_cond_lhs (stmt
)));
4069 /* If the range of values taken by OP can be inferred after STMT executes,
4070 return the comparison code (COMP_CODE_P) and value (VAL_P) that
4071 describes the inferred range. Return true if a range could be
4075 infer_value_range (gimple stmt
, tree op
, enum tree_code
*comp_code_p
, tree
*val_p
)
4078 *comp_code_p
= ERROR_MARK
;
4080 /* Do not attempt to infer anything in names that flow through
4082 if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (op
))
4085 /* Similarly, don't infer anything from statements that may throw
4087 if (stmt_could_throw_p (stmt
))
4090 /* If STMT is the last statement of a basic block with no
4091 successors, there is no point inferring anything about any of its
4092 operands. We would not be able to find a proper insertion point
4093 for the assertion, anyway. */
4094 if (stmt_ends_bb_p (stmt
) && EDGE_COUNT (gimple_bb (stmt
)->succs
) == 0)
4097 /* We can only assume that a pointer dereference will yield
4098 non-NULL if -fdelete-null-pointer-checks is enabled. */
4099 if (flag_delete_null_pointer_checks
4100 && POINTER_TYPE_P (TREE_TYPE (op
))
4101 && gimple_code (stmt
) != GIMPLE_ASM
)
4103 unsigned num_uses
, num_loads
, num_stores
;
4105 count_uses_and_derefs (op
, stmt
, &num_uses
, &num_loads
, &num_stores
);
4106 if (num_loads
+ num_stores
> 0)
4108 *val_p
= build_int_cst (TREE_TYPE (op
), 0);
4109 *comp_code_p
= NE_EXPR
;
4118 void dump_asserts_for (FILE *, tree
);
4119 void debug_asserts_for (tree
);
4120 void dump_all_asserts (FILE *);
4121 void debug_all_asserts (void);
4123 /* Dump all the registered assertions for NAME to FILE. */
4126 dump_asserts_for (FILE *file
, tree name
)
4130 fprintf (file
, "Assertions to be inserted for ");
4131 print_generic_expr (file
, name
, 0);
4132 fprintf (file
, "\n");
4134 loc
= asserts_for
[SSA_NAME_VERSION (name
)];
4137 fprintf (file
, "\t");
4138 print_gimple_stmt (file
, gsi_stmt (loc
->si
), 0, 0);
4139 fprintf (file
, "\n\tBB #%d", loc
->bb
->index
);
4142 fprintf (file
, "\n\tEDGE %d->%d", loc
->e
->src
->index
,
4143 loc
->e
->dest
->index
);
4144 dump_edge_info (file
, loc
->e
, dump_flags
, 0);
4146 fprintf (file
, "\n\tPREDICATE: ");
4147 print_generic_expr (file
, name
, 0);
4148 fprintf (file
, " %s ", tree_code_name
[(int)loc
->comp_code
]);
4149 print_generic_expr (file
, loc
->val
, 0);
4150 fprintf (file
, "\n\n");
4154 fprintf (file
, "\n");
4158 /* Dump all the registered assertions for NAME to stderr. */
4161 debug_asserts_for (tree name
)
4163 dump_asserts_for (stderr
, name
);
4167 /* Dump all the registered assertions for all the names to FILE. */
4170 dump_all_asserts (FILE *file
)
4175 fprintf (file
, "\nASSERT_EXPRs to be inserted\n\n");
4176 EXECUTE_IF_SET_IN_BITMAP (need_assert_for
, 0, i
, bi
)
4177 dump_asserts_for (file
, ssa_name (i
));
4178 fprintf (file
, "\n");
4182 /* Dump all the registered assertions for all the names to stderr. */
4185 debug_all_asserts (void)
4187 dump_all_asserts (stderr
);
4191 /* If NAME doesn't have an ASSERT_EXPR registered for asserting
4192 'EXPR COMP_CODE VAL' at a location that dominates block BB or
4193 E->DEST, then register this location as a possible insertion point
4194 for ASSERT_EXPR <NAME, EXPR COMP_CODE VAL>.
4196 BB, E and SI provide the exact insertion point for the new
4197 ASSERT_EXPR. If BB is NULL, then the ASSERT_EXPR is to be inserted
4198 on edge E. Otherwise, if E is NULL, the ASSERT_EXPR is inserted on
4199 BB. If SI points to a COND_EXPR or a SWITCH_EXPR statement, then E
4200 must not be NULL. */
4203 register_new_assert_for (tree name
, tree expr
,
4204 enum tree_code comp_code
,
4208 gimple_stmt_iterator si
)
4210 assert_locus_t n
, loc
, last_loc
;
4211 basic_block dest_bb
;
4213 gcc_checking_assert (bb
== NULL
|| e
== NULL
);
4216 gcc_checking_assert (gimple_code (gsi_stmt (si
)) != GIMPLE_COND
4217 && gimple_code (gsi_stmt (si
)) != GIMPLE_SWITCH
);
4219 /* Never build an assert comparing against an integer constant with
4220 TREE_OVERFLOW set. This confuses our undefined overflow warning
4222 if (TREE_CODE (val
) == INTEGER_CST
4223 && TREE_OVERFLOW (val
))
4224 val
= build_int_cst_wide (TREE_TYPE (val
),
4225 TREE_INT_CST_LOW (val
), TREE_INT_CST_HIGH (val
));
4227 /* The new assertion A will be inserted at BB or E. We need to
4228 determine if the new location is dominated by a previously
4229 registered location for A. If we are doing an edge insertion,
4230 assume that A will be inserted at E->DEST. Note that this is not
4233 If E is a critical edge, it will be split. But even if E is
4234 split, the new block will dominate the same set of blocks that
4237 The reverse, however, is not true, blocks dominated by E->DEST
4238 will not be dominated by the new block created to split E. So,
4239 if the insertion location is on a critical edge, we will not use
4240 the new location to move another assertion previously registered
4241 at a block dominated by E->DEST. */
4242 dest_bb
= (bb
) ? bb
: e
->dest
;
4244 /* If NAME already has an ASSERT_EXPR registered for COMP_CODE and
4245 VAL at a block dominating DEST_BB, then we don't need to insert a new
4246 one. Similarly, if the same assertion already exists at a block
4247 dominated by DEST_BB and the new location is not on a critical
4248 edge, then update the existing location for the assertion (i.e.,
4249 move the assertion up in the dominance tree).
4251 Note, this is implemented as a simple linked list because there
4252 should not be more than a handful of assertions registered per
4253 name. If this becomes a performance problem, a table hashed by
4254 COMP_CODE and VAL could be implemented. */
4255 loc
= asserts_for
[SSA_NAME_VERSION (name
)];
4259 if (loc
->comp_code
== comp_code
4261 || operand_equal_p (loc
->val
, val
, 0))
4262 && (loc
->expr
== expr
4263 || operand_equal_p (loc
->expr
, expr
, 0)))
4265 /* If the assertion NAME COMP_CODE VAL has already been
4266 registered at a basic block that dominates DEST_BB, then
4267 we don't need to insert the same assertion again. Note
4268 that we don't check strict dominance here to avoid
4269 replicating the same assertion inside the same basic
4270 block more than once (e.g., when a pointer is
4271 dereferenced several times inside a block).
4273 An exception to this rule are edge insertions. If the
4274 new assertion is to be inserted on edge E, then it will
4275 dominate all the other insertions that we may want to
4276 insert in DEST_BB. So, if we are doing an edge
4277 insertion, don't do this dominance check. */
4279 && dominated_by_p (CDI_DOMINATORS
, dest_bb
, loc
->bb
))
4282 /* Otherwise, if E is not a critical edge and DEST_BB
4283 dominates the existing location for the assertion, move
4284 the assertion up in the dominance tree by updating its
4285 location information. */
4286 if ((e
== NULL
|| !EDGE_CRITICAL_P (e
))
4287 && dominated_by_p (CDI_DOMINATORS
, loc
->bb
, dest_bb
))
4296 /* Update the last node of the list and move to the next one. */
4301 /* If we didn't find an assertion already registered for
4302 NAME COMP_CODE VAL, add a new one at the end of the list of
4303 assertions associated with NAME. */
4304 n
= XNEW (struct assert_locus_d
);
4308 n
->comp_code
= comp_code
;
4316 asserts_for
[SSA_NAME_VERSION (name
)] = n
;
4318 bitmap_set_bit (need_assert_for
, SSA_NAME_VERSION (name
));
4321 /* (COND_OP0 COND_CODE COND_OP1) is a predicate which uses NAME.
4322 Extract a suitable test code and value and store them into *CODE_P and
4323 *VAL_P so the predicate is normalized to NAME *CODE_P *VAL_P.
4325 If no extraction was possible, return FALSE, otherwise return TRUE.
4327 If INVERT is true, then we invert the result stored into *CODE_P. */
4330 extract_code_and_val_from_cond_with_ops (tree name
, enum tree_code cond_code
,
4331 tree cond_op0
, tree cond_op1
,
4332 bool invert
, enum tree_code
*code_p
,
4335 enum tree_code comp_code
;
4338 /* Otherwise, we have a comparison of the form NAME COMP VAL
4339 or VAL COMP NAME. */
4340 if (name
== cond_op1
)
4342 /* If the predicate is of the form VAL COMP NAME, flip
4343 COMP around because we need to register NAME as the
4344 first operand in the predicate. */
4345 comp_code
= swap_tree_comparison (cond_code
);
4350 /* The comparison is of the form NAME COMP VAL, so the
4351 comparison code remains unchanged. */
4352 comp_code
= cond_code
;
4356 /* Invert the comparison code as necessary. */
4358 comp_code
= invert_tree_comparison (comp_code
, 0);
4360 /* VRP does not handle float types. */
4361 if (SCALAR_FLOAT_TYPE_P (TREE_TYPE (val
)))
4364 /* Do not register always-false predicates.
4365 FIXME: this works around a limitation in fold() when dealing with
4366 enumerations. Given 'enum { N1, N2 } x;', fold will not
4367 fold 'if (x > N2)' to 'if (0)'. */
4368 if ((comp_code
== GT_EXPR
|| comp_code
== LT_EXPR
)
4369 && INTEGRAL_TYPE_P (TREE_TYPE (val
)))
4371 tree min
= TYPE_MIN_VALUE (TREE_TYPE (val
));
4372 tree max
= TYPE_MAX_VALUE (TREE_TYPE (val
));
4374 if (comp_code
== GT_EXPR
4376 || compare_values (val
, max
) == 0))
4379 if (comp_code
== LT_EXPR
4381 || compare_values (val
, min
) == 0))
4384 *code_p
= comp_code
;
4389 /* Find out smallest RES where RES > VAL && (RES & MASK) == RES, if any
4390 (otherwise return VAL). VAL and MASK must be zero-extended for
4391 precision PREC. If SGNBIT is non-zero, first xor VAL with SGNBIT
4392 (to transform signed values into unsigned) and at the end xor
4396 masked_increment (double_int val
, double_int mask
, double_int sgnbit
,
4399 double_int bit
= double_int_one
, res
;
4402 val
= double_int_xor (val
, sgnbit
);
4403 for (i
= 0; i
< prec
; i
++, bit
= double_int_add (bit
, bit
))
4406 if (double_int_zero_p (double_int_and (res
, bit
)))
4408 res
= double_int_sub (bit
, double_int_one
);
4409 res
= double_int_and_not (double_int_add (val
, bit
), res
);
4410 res
= double_int_and (res
, mask
);
4411 if (double_int_ucmp (res
, val
) > 0)
4412 return double_int_xor (res
, sgnbit
);
4414 return double_int_xor (val
, sgnbit
);
4417 /* Try to register an edge assertion for SSA name NAME on edge E for
4418 the condition COND contributing to the conditional jump pointed to by BSI.
4419 Invert the condition COND if INVERT is true.
4420 Return true if an assertion for NAME could be registered. */
4423 register_edge_assert_for_2 (tree name
, edge e
, gimple_stmt_iterator bsi
,
4424 enum tree_code cond_code
,
4425 tree cond_op0
, tree cond_op1
, bool invert
)
4428 enum tree_code comp_code
;
4429 bool retval
= false;
4431 if (!extract_code_and_val_from_cond_with_ops (name
, cond_code
,
4434 invert
, &comp_code
, &val
))
4437 /* Only register an ASSERT_EXPR if NAME was found in the sub-graph
4438 reachable from E. */
4439 if (live_on_edge (e
, name
)
4440 && !has_single_use (name
))
4442 register_new_assert_for (name
, name
, comp_code
, val
, NULL
, e
, bsi
);
4446 /* In the case of NAME <= CST and NAME being defined as
4447 NAME = (unsigned) NAME2 + CST2 we can assert NAME2 >= -CST2
4448 and NAME2 <= CST - CST2. We can do the same for NAME > CST.
4449 This catches range and anti-range tests. */
4450 if ((comp_code
== LE_EXPR
4451 || comp_code
== GT_EXPR
)
4452 && TREE_CODE (val
) == INTEGER_CST
4453 && TYPE_UNSIGNED (TREE_TYPE (val
)))
4455 gimple def_stmt
= SSA_NAME_DEF_STMT (name
);
4456 tree cst2
= NULL_TREE
, name2
= NULL_TREE
, name3
= NULL_TREE
;
4458 /* Extract CST2 from the (optional) addition. */
4459 if (is_gimple_assign (def_stmt
)
4460 && gimple_assign_rhs_code (def_stmt
) == PLUS_EXPR
)
4462 name2
= gimple_assign_rhs1 (def_stmt
);
4463 cst2
= gimple_assign_rhs2 (def_stmt
);
4464 if (TREE_CODE (name2
) == SSA_NAME
4465 && TREE_CODE (cst2
) == INTEGER_CST
)
4466 def_stmt
= SSA_NAME_DEF_STMT (name2
);
4469 /* Extract NAME2 from the (optional) sign-changing cast. */
4470 if (gimple_assign_cast_p (def_stmt
))
4472 if (CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (def_stmt
))
4473 && ! TYPE_UNSIGNED (TREE_TYPE (gimple_assign_rhs1 (def_stmt
)))
4474 && (TYPE_PRECISION (gimple_expr_type (def_stmt
))
4475 == TYPE_PRECISION (TREE_TYPE (gimple_assign_rhs1 (def_stmt
)))))
4476 name3
= gimple_assign_rhs1 (def_stmt
);
4479 /* If name3 is used later, create an ASSERT_EXPR for it. */
4480 if (name3
!= NULL_TREE
4481 && TREE_CODE (name3
) == SSA_NAME
4482 && (cst2
== NULL_TREE
4483 || TREE_CODE (cst2
) == INTEGER_CST
)
4484 && INTEGRAL_TYPE_P (TREE_TYPE (name3
))
4485 && live_on_edge (e
, name3
)
4486 && !has_single_use (name3
))
4490 /* Build an expression for the range test. */
4491 tmp
= build1 (NOP_EXPR
, TREE_TYPE (name
), name3
);
4492 if (cst2
!= NULL_TREE
)
4493 tmp
= build2 (PLUS_EXPR
, TREE_TYPE (name
), tmp
, cst2
);
4497 fprintf (dump_file
, "Adding assert for ");
4498 print_generic_expr (dump_file
, name3
, 0);
4499 fprintf (dump_file
, " from ");
4500 print_generic_expr (dump_file
, tmp
, 0);
4501 fprintf (dump_file
, "\n");
4504 register_new_assert_for (name3
, tmp
, comp_code
, val
, NULL
, e
, bsi
);
4509 /* If name2 is used later, create an ASSERT_EXPR for it. */
4510 if (name2
!= NULL_TREE
4511 && TREE_CODE (name2
) == SSA_NAME
4512 && TREE_CODE (cst2
) == INTEGER_CST
4513 && INTEGRAL_TYPE_P (TREE_TYPE (name2
))
4514 && live_on_edge (e
, name2
)
4515 && !has_single_use (name2
))
4519 /* Build an expression for the range test. */
4521 if (TREE_TYPE (name
) != TREE_TYPE (name2
))
4522 tmp
= build1 (NOP_EXPR
, TREE_TYPE (name
), tmp
);
4523 if (cst2
!= NULL_TREE
)
4524 tmp
= build2 (PLUS_EXPR
, TREE_TYPE (name
), tmp
, cst2
);
4528 fprintf (dump_file
, "Adding assert for ");
4529 print_generic_expr (dump_file
, name2
, 0);
4530 fprintf (dump_file
, " from ");
4531 print_generic_expr (dump_file
, tmp
, 0);
4532 fprintf (dump_file
, "\n");
4535 register_new_assert_for (name2
, tmp
, comp_code
, val
, NULL
, e
, bsi
);
4541 if (TREE_CODE_CLASS (comp_code
) == tcc_comparison
4542 && TREE_CODE (val
) == INTEGER_CST
)
4544 gimple def_stmt
= SSA_NAME_DEF_STMT (name
);
4545 tree name2
= NULL_TREE
, names
[2], cst2
= NULL_TREE
;
4546 tree val2
= NULL_TREE
;
4547 double_int mask
= double_int_zero
;
4548 unsigned int prec
= TYPE_PRECISION (TREE_TYPE (val
));
4550 /* Add asserts for NAME cmp CST and NAME being defined
4551 as NAME = (int) NAME2. */
4552 if (!TYPE_UNSIGNED (TREE_TYPE (val
))
4553 && (comp_code
== LE_EXPR
|| comp_code
== LT_EXPR
4554 || comp_code
== GT_EXPR
|| comp_code
== GE_EXPR
)
4555 && gimple_assign_cast_p (def_stmt
))
4557 name2
= gimple_assign_rhs1 (def_stmt
);
4558 if (CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (def_stmt
))
4559 && INTEGRAL_TYPE_P (TREE_TYPE (name2
))
4560 && TYPE_UNSIGNED (TREE_TYPE (name2
))
4561 && prec
== TYPE_PRECISION (TREE_TYPE (name2
))
4562 && (comp_code
== LE_EXPR
|| comp_code
== GT_EXPR
4563 || !tree_int_cst_equal (val
,
4564 TYPE_MIN_VALUE (TREE_TYPE (val
))))
4565 && live_on_edge (e
, name2
)
4566 && !has_single_use (name2
))
4569 enum tree_code new_comp_code
= comp_code
;
4571 cst
= fold_convert (TREE_TYPE (name2
),
4572 TYPE_MIN_VALUE (TREE_TYPE (val
)));
4573 /* Build an expression for the range test. */
4574 tmp
= build2 (PLUS_EXPR
, TREE_TYPE (name2
), name2
, cst
);
4575 cst
= fold_build2 (PLUS_EXPR
, TREE_TYPE (name2
), cst
,
4576 fold_convert (TREE_TYPE (name2
), val
));
4577 if (comp_code
== LT_EXPR
|| comp_code
== GE_EXPR
)
4579 new_comp_code
= comp_code
== LT_EXPR
? LE_EXPR
: GT_EXPR
;
4580 cst
= fold_build2 (MINUS_EXPR
, TREE_TYPE (name2
), cst
,
4581 build_int_cst (TREE_TYPE (name2
), 1));
4586 fprintf (dump_file
, "Adding assert for ");
4587 print_generic_expr (dump_file
, name2
, 0);
4588 fprintf (dump_file
, " from ");
4589 print_generic_expr (dump_file
, tmp
, 0);
4590 fprintf (dump_file
, "\n");
4593 register_new_assert_for (name2
, tmp
, new_comp_code
, cst
, NULL
,
4600 /* Add asserts for NAME cmp CST and NAME being defined as
4601 NAME = NAME2 >> CST2.
4603 Extract CST2 from the right shift. */
4604 if (is_gimple_assign (def_stmt
)
4605 && gimple_assign_rhs_code (def_stmt
) == RSHIFT_EXPR
)
4607 name2
= gimple_assign_rhs1 (def_stmt
);
4608 cst2
= gimple_assign_rhs2 (def_stmt
);
4609 if (TREE_CODE (name2
) == SSA_NAME
4610 && host_integerp (cst2
, 1)
4611 && INTEGRAL_TYPE_P (TREE_TYPE (name2
))
4612 && IN_RANGE (tree_low_cst (cst2
, 1), 1, prec
- 1)
4613 && prec
<= HOST_BITS_PER_DOUBLE_INT
4614 && prec
== GET_MODE_PRECISION (TYPE_MODE (TREE_TYPE (val
)))
4615 && live_on_edge (e
, name2
)
4616 && !has_single_use (name2
))
4618 mask
= double_int_mask (tree_low_cst (cst2
, 1));
4619 val2
= fold_binary (LSHIFT_EXPR
, TREE_TYPE (val
), val
, cst2
);
4622 if (val2
!= NULL_TREE
4623 && TREE_CODE (val2
) == INTEGER_CST
4624 && simple_cst_equal (fold_build2 (RSHIFT_EXPR
,
4628 enum tree_code new_comp_code
= comp_code
;
4632 if (comp_code
== EQ_EXPR
|| comp_code
== NE_EXPR
)
4634 if (!TYPE_UNSIGNED (TREE_TYPE (val
)))
4636 tree type
= build_nonstandard_integer_type (prec
, 1);
4637 tmp
= build1 (NOP_EXPR
, type
, name2
);
4638 val2
= fold_convert (type
, val2
);
4640 tmp
= fold_build2 (MINUS_EXPR
, TREE_TYPE (tmp
), tmp
, val2
);
4641 new_val
= double_int_to_tree (TREE_TYPE (tmp
), mask
);
4642 new_comp_code
= comp_code
== EQ_EXPR
? LE_EXPR
: GT_EXPR
;
4644 else if (comp_code
== LT_EXPR
|| comp_code
== GE_EXPR
)
4649 = double_int_max_value (prec
, TYPE_UNSIGNED (TREE_TYPE (val
)));
4650 mask
= double_int_ior (tree_to_double_int (val2
), mask
);
4651 if (double_int_equal_p (mask
, maxval
))
4652 new_val
= NULL_TREE
;
4654 new_val
= double_int_to_tree (TREE_TYPE (val2
), mask
);
4661 fprintf (dump_file
, "Adding assert for ");
4662 print_generic_expr (dump_file
, name2
, 0);
4663 fprintf (dump_file
, " from ");
4664 print_generic_expr (dump_file
, tmp
, 0);
4665 fprintf (dump_file
, "\n");
4668 register_new_assert_for (name2
, tmp
, new_comp_code
, new_val
,
4674 /* Add asserts for NAME cmp CST and NAME being defined as
4675 NAME = NAME2 & CST2.
4677 Extract CST2 from the and. */
4678 names
[0] = NULL_TREE
;
4679 names
[1] = NULL_TREE
;
4681 if (is_gimple_assign (def_stmt
)
4682 && gimple_assign_rhs_code (def_stmt
) == BIT_AND_EXPR
)
4684 name2
= gimple_assign_rhs1 (def_stmt
);
4685 cst2
= gimple_assign_rhs2 (def_stmt
);
4686 if (TREE_CODE (name2
) == SSA_NAME
4687 && INTEGRAL_TYPE_P (TREE_TYPE (name2
))
4688 && TREE_CODE (cst2
) == INTEGER_CST
4689 && !integer_zerop (cst2
)
4690 && prec
<= HOST_BITS_PER_DOUBLE_INT
4692 || TYPE_UNSIGNED (TREE_TYPE (val
))))
4694 gimple def_stmt2
= SSA_NAME_DEF_STMT (name2
);
4695 if (gimple_assign_cast_p (def_stmt2
))
4697 names
[1] = gimple_assign_rhs1 (def_stmt2
);
4698 if (!CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (def_stmt2
))
4699 || !INTEGRAL_TYPE_P (TREE_TYPE (names
[1]))
4700 || (TYPE_PRECISION (TREE_TYPE (name2
))
4701 != TYPE_PRECISION (TREE_TYPE (names
[1])))
4702 || !live_on_edge (e
, names
[1])
4703 || has_single_use (names
[1]))
4704 names
[1] = NULL_TREE
;
4706 if (live_on_edge (e
, name2
)
4707 && !has_single_use (name2
))
4711 if (names
[0] || names
[1])
4713 double_int minv
, maxv
= double_int_zero
, valv
, cst2v
;
4714 double_int tem
, sgnbit
;
4715 bool valid_p
= false, valn
= false, cst2n
= false;
4716 enum tree_code ccode
= comp_code
;
4718 valv
= double_int_zext (tree_to_double_int (val
), prec
);
4719 cst2v
= double_int_zext (tree_to_double_int (cst2
), prec
);
4720 if (!TYPE_UNSIGNED (TREE_TYPE (val
)))
4722 valn
= double_int_negative_p (double_int_sext (valv
, prec
));
4723 cst2n
= double_int_negative_p (double_int_sext (cst2v
, prec
));
4725 /* If CST2 doesn't have most significant bit set,
4726 but VAL is negative, we have comparison like
4727 if ((x & 0x123) > -4) (always true). Just give up. */
4731 sgnbit
= double_int_zext (double_int_lshift (double_int_one
,
4735 sgnbit
= double_int_zero
;
4736 minv
= double_int_and (valv
, cst2v
);
4740 /* Minimum unsigned value for equality is VAL & CST2
4741 (should be equal to VAL, otherwise we probably should
4742 have folded the comparison into false) and
4743 maximum unsigned value is VAL | ~CST2. */
4744 maxv
= double_int_ior (valv
, double_int_not (cst2v
));
4745 maxv
= double_int_zext (maxv
, prec
);
4749 tem
= double_int_ior (valv
, double_int_not (cst2v
));
4750 tem
= double_int_zext (tem
, prec
);
4751 /* If VAL is 0, handle (X & CST2) != 0 as (X & CST2) > 0U. */
4752 if (double_int_zero_p (valv
))
4755 sgnbit
= double_int_zero
;
4758 /* If (VAL | ~CST2) is all ones, handle it as
4759 (X & CST2) < VAL. */
4760 if (double_int_equal_p (tem
, double_int_mask (prec
)))
4764 sgnbit
= double_int_zero
;
4768 && double_int_negative_p (double_int_sext (cst2v
, prec
)))
4769 sgnbit
= double_int_zext (double_int_lshift (double_int_one
,
4772 if (!double_int_zero_p (sgnbit
))
4774 if (double_int_equal_p (valv
, sgnbit
))
4780 if (double_int_equal_p (tem
, double_int_mask (prec
- 1)))
4786 sgnbit
= double_int_zero
;
4790 /* Minimum unsigned value for >= if (VAL & CST2) == VAL
4791 is VAL and maximum unsigned value is ~0. For signed
4792 comparison, if CST2 doesn't have most significant bit
4793 set, handle it similarly. If CST2 has MSB set,
4794 the minimum is the same, and maximum is ~0U/2. */
4795 if (!double_int_equal_p (minv
, valv
))
4797 /* If (VAL & CST2) != VAL, X & CST2 can't be equal to
4799 minv
= masked_increment (valv
, cst2v
, sgnbit
, prec
);
4800 if (double_int_equal_p (minv
, valv
))
4803 maxv
= double_int_mask (prec
- (cst2n
? 1 : 0));
4808 /* Find out smallest MINV where MINV > VAL
4809 && (MINV & CST2) == MINV, if any. If VAL is signed and
4810 CST2 has MSB set, compute it biased by 1 << (prec - 1). */
4811 minv
= masked_increment (valv
, cst2v
, sgnbit
, prec
);
4812 if (double_int_equal_p (minv
, valv
))
4814 maxv
= double_int_mask (prec
- (cst2n
? 1 : 0));
4818 /* Minimum unsigned value for <= is 0 and maximum
4819 unsigned value is VAL | ~CST2 if (VAL & CST2) == VAL.
4820 Otherwise, find smallest VAL2 where VAL2 > VAL
4821 && (VAL2 & CST2) == VAL2 and use (VAL2 - 1) | ~CST2
4823 For signed comparison, if CST2 doesn't have most
4824 significant bit set, handle it similarly. If CST2 has
4825 MSB set, the maximum is the same and minimum is INT_MIN. */
4826 if (double_int_equal_p (minv
, valv
))
4830 maxv
= masked_increment (valv
, cst2v
, sgnbit
, prec
);
4831 if (double_int_equal_p (maxv
, valv
))
4833 maxv
= double_int_sub (maxv
, double_int_one
);
4835 maxv
= double_int_ior (maxv
, double_int_not (cst2v
));
4836 maxv
= double_int_zext (maxv
, prec
);
4842 /* Minimum unsigned value for < is 0 and maximum
4843 unsigned value is (VAL-1) | ~CST2 if (VAL & CST2) == VAL.
4844 Otherwise, find smallest VAL2 where VAL2 > VAL
4845 && (VAL2 & CST2) == VAL2 and use (VAL2 - 1) | ~CST2
4847 For signed comparison, if CST2 doesn't have most
4848 significant bit set, handle it similarly. If CST2 has
4849 MSB set, the maximum is the same and minimum is INT_MIN. */
4850 if (double_int_equal_p (minv
, valv
))
4852 if (double_int_equal_p (valv
, sgnbit
))
4858 maxv
= masked_increment (valv
, cst2v
, sgnbit
, prec
);
4859 if (double_int_equal_p (maxv
, valv
))
4862 maxv
= double_int_sub (maxv
, double_int_one
);
4863 maxv
= double_int_ior (maxv
, double_int_not (cst2v
));
4864 maxv
= double_int_zext (maxv
, prec
);
4872 && !double_int_equal_p (double_int_zext (double_int_sub (maxv
,
4875 double_int_mask (prec
)))
4877 tree tmp
, new_val
, type
;
4880 for (i
= 0; i
< 2; i
++)
4883 double_int maxv2
= maxv
;
4885 type
= TREE_TYPE (names
[i
]);
4886 if (!TYPE_UNSIGNED (type
))
4888 type
= build_nonstandard_integer_type (prec
, 1);
4889 tmp
= build1 (NOP_EXPR
, type
, names
[i
]);
4891 if (!double_int_zero_p (minv
))
4893 tmp
= build2 (PLUS_EXPR
, type
, tmp
,
4894 double_int_to_tree (type
,
4895 double_int_neg (minv
)));
4896 maxv2
= double_int_sub (maxv
, minv
);
4898 new_val
= double_int_to_tree (type
, maxv2
);
4902 fprintf (dump_file
, "Adding assert for ");
4903 print_generic_expr (dump_file
, names
[i
], 0);
4904 fprintf (dump_file
, " from ");
4905 print_generic_expr (dump_file
, tmp
, 0);
4906 fprintf (dump_file
, "\n");
4909 register_new_assert_for (names
[i
], tmp
, LE_EXPR
,
4910 new_val
, NULL
, e
, bsi
);
4920 /* OP is an operand of a truth value expression which is known to have
4921 a particular value. Register any asserts for OP and for any
4922 operands in OP's defining statement.
4924 If CODE is EQ_EXPR, then we want to register OP is zero (false),
4925 if CODE is NE_EXPR, then we want to register OP is nonzero (true). */
4928 register_edge_assert_for_1 (tree op
, enum tree_code code
,
4929 edge e
, gimple_stmt_iterator bsi
)
4931 bool retval
= false;
4934 enum tree_code rhs_code
;
4936 /* We only care about SSA_NAMEs. */
4937 if (TREE_CODE (op
) != SSA_NAME
)
4940 /* We know that OP will have a zero or nonzero value. If OP is used
4941 more than once go ahead and register an assert for OP.
4943 The FOUND_IN_SUBGRAPH support is not helpful in this situation as
4944 it will always be set for OP (because OP is used in a COND_EXPR in
4946 if (!has_single_use (op
))
4948 val
= build_int_cst (TREE_TYPE (op
), 0);
4949 register_new_assert_for (op
, op
, code
, val
, NULL
, e
, bsi
);
4953 /* Now look at how OP is set. If it's set from a comparison,
4954 a truth operation or some bit operations, then we may be able
4955 to register information about the operands of that assignment. */
4956 op_def
= SSA_NAME_DEF_STMT (op
);
4957 if (gimple_code (op_def
) != GIMPLE_ASSIGN
)
4960 rhs_code
= gimple_assign_rhs_code (op_def
);
4962 if (TREE_CODE_CLASS (rhs_code
) == tcc_comparison
)
4964 bool invert
= (code
== EQ_EXPR
? true : false);
4965 tree op0
= gimple_assign_rhs1 (op_def
);
4966 tree op1
= gimple_assign_rhs2 (op_def
);
4968 if (TREE_CODE (op0
) == SSA_NAME
)
4969 retval
|= register_edge_assert_for_2 (op0
, e
, bsi
, rhs_code
, op0
, op1
,
4971 if (TREE_CODE (op1
) == SSA_NAME
)
4972 retval
|= register_edge_assert_for_2 (op1
, e
, bsi
, rhs_code
, op0
, op1
,
4975 else if ((code
== NE_EXPR
4976 && gimple_assign_rhs_code (op_def
) == BIT_AND_EXPR
)
4978 && gimple_assign_rhs_code (op_def
) == BIT_IOR_EXPR
))
4980 /* Recurse on each operand. */
4981 retval
|= register_edge_assert_for_1 (gimple_assign_rhs1 (op_def
),
4983 retval
|= register_edge_assert_for_1 (gimple_assign_rhs2 (op_def
),
4986 else if (gimple_assign_rhs_code (op_def
) == BIT_NOT_EXPR
4987 && TYPE_PRECISION (TREE_TYPE (gimple_assign_lhs (op_def
))) == 1)
4989 /* Recurse, flipping CODE. */
4990 code
= invert_tree_comparison (code
, false);
4991 retval
|= register_edge_assert_for_1 (gimple_assign_rhs1 (op_def
),
4994 else if (gimple_assign_rhs_code (op_def
) == SSA_NAME
)
4996 /* Recurse through the copy. */
4997 retval
|= register_edge_assert_for_1 (gimple_assign_rhs1 (op_def
),
5000 else if (CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (op_def
)))
5002 /* Recurse through the type conversion. */
5003 retval
|= register_edge_assert_for_1 (gimple_assign_rhs1 (op_def
),
5010 /* Try to register an edge assertion for SSA name NAME on edge E for
5011 the condition COND contributing to the conditional jump pointed to by SI.
5012 Return true if an assertion for NAME could be registered. */
5015 register_edge_assert_for (tree name
, edge e
, gimple_stmt_iterator si
,
5016 enum tree_code cond_code
, tree cond_op0
,
5020 enum tree_code comp_code
;
5021 bool retval
= false;
5022 bool is_else_edge
= (e
->flags
& EDGE_FALSE_VALUE
) != 0;
5024 /* Do not attempt to infer anything in names that flow through
5026 if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (name
))
5029 if (!extract_code_and_val_from_cond_with_ops (name
, cond_code
,
5035 /* Register ASSERT_EXPRs for name. */
5036 retval
|= register_edge_assert_for_2 (name
, e
, si
, cond_code
, cond_op0
,
5037 cond_op1
, is_else_edge
);
5040 /* If COND is effectively an equality test of an SSA_NAME against
5041 the value zero or one, then we may be able to assert values
5042 for SSA_NAMEs which flow into COND. */
5044 /* In the case of NAME == 1 or NAME != 0, for BIT_AND_EXPR defining
5045 statement of NAME we can assert both operands of the BIT_AND_EXPR
5046 have nonzero value. */
5047 if (((comp_code
== EQ_EXPR
&& integer_onep (val
))
5048 || (comp_code
== NE_EXPR
&& integer_zerop (val
))))
5050 gimple def_stmt
= SSA_NAME_DEF_STMT (name
);
5052 if (is_gimple_assign (def_stmt
)
5053 && gimple_assign_rhs_code (def_stmt
) == BIT_AND_EXPR
)
5055 tree op0
= gimple_assign_rhs1 (def_stmt
);
5056 tree op1
= gimple_assign_rhs2 (def_stmt
);
5057 retval
|= register_edge_assert_for_1 (op0
, NE_EXPR
, e
, si
);
5058 retval
|= register_edge_assert_for_1 (op1
, NE_EXPR
, e
, si
);
5062 /* In the case of NAME == 0 or NAME != 1, for BIT_IOR_EXPR defining
5063 statement of NAME we can assert both operands of the BIT_IOR_EXPR
5065 if (((comp_code
== EQ_EXPR
&& integer_zerop (val
))
5066 || (comp_code
== NE_EXPR
&& integer_onep (val
))))
5068 gimple def_stmt
= SSA_NAME_DEF_STMT (name
);
5070 /* For BIT_IOR_EXPR only if NAME == 0 both operands have
5071 necessarily zero value, or if type-precision is one. */
5072 if (is_gimple_assign (def_stmt
)
5073 && (gimple_assign_rhs_code (def_stmt
) == BIT_IOR_EXPR
5074 && (TYPE_PRECISION (TREE_TYPE (name
)) == 1
5075 || comp_code
== EQ_EXPR
)))
5077 tree op0
= gimple_assign_rhs1 (def_stmt
);
5078 tree op1
= gimple_assign_rhs2 (def_stmt
);
5079 retval
|= register_edge_assert_for_1 (op0
, EQ_EXPR
, e
, si
);
5080 retval
|= register_edge_assert_for_1 (op1
, EQ_EXPR
, e
, si
);
5088 /* Determine whether the outgoing edges of BB should receive an
5089 ASSERT_EXPR for each of the operands of BB's LAST statement.
5090 The last statement of BB must be a COND_EXPR.
5092 If any of the sub-graphs rooted at BB have an interesting use of
5093 the predicate operands, an assert location node is added to the
5094 list of assertions for the corresponding operands. */
5097 find_conditional_asserts (basic_block bb
, gimple last
)
5100 gimple_stmt_iterator bsi
;
5106 need_assert
= false;
5107 bsi
= gsi_for_stmt (last
);
5109 /* Look for uses of the operands in each of the sub-graphs
5110 rooted at BB. We need to check each of the outgoing edges
5111 separately, so that we know what kind of ASSERT_EXPR to
5113 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
5118 /* Register the necessary assertions for each operand in the
5119 conditional predicate. */
5120 FOR_EACH_SSA_TREE_OPERAND (op
, last
, iter
, SSA_OP_USE
)
5122 need_assert
|= register_edge_assert_for (op
, e
, bsi
,
5123 gimple_cond_code (last
),
5124 gimple_cond_lhs (last
),
5125 gimple_cond_rhs (last
));
5138 /* Compare two case labels sorting first by the destination bb index
5139 and then by the case value. */
5142 compare_case_labels (const void *p1
, const void *p2
)
5144 const struct case_info
*ci1
= (const struct case_info
*) p1
;
5145 const struct case_info
*ci2
= (const struct case_info
*) p2
;
5146 int idx1
= ci1
->bb
->index
;
5147 int idx2
= ci2
->bb
->index
;
5151 else if (idx1
== idx2
)
5153 /* Make sure the default label is first in a group. */
5154 if (!CASE_LOW (ci1
->expr
))
5156 else if (!CASE_LOW (ci2
->expr
))
5159 return tree_int_cst_compare (CASE_LOW (ci1
->expr
),
5160 CASE_LOW (ci2
->expr
));
5166 /* Determine whether the outgoing edges of BB should receive an
5167 ASSERT_EXPR for each of the operands of BB's LAST statement.
5168 The last statement of BB must be a SWITCH_EXPR.
5170 If any of the sub-graphs rooted at BB have an interesting use of
5171 the predicate operands, an assert location node is added to the
5172 list of assertions for the corresponding operands. */
5175 find_switch_asserts (basic_block bb
, gimple last
)
5178 gimple_stmt_iterator bsi
;
5181 struct case_info
*ci
;
5182 size_t n
= gimple_switch_num_labels (last
);
5183 #if GCC_VERSION >= 4000
5186 /* Work around GCC 3.4 bug (PR 37086). */
5187 volatile unsigned int idx
;
5190 need_assert
= false;
5191 bsi
= gsi_for_stmt (last
);
5192 op
= gimple_switch_index (last
);
5193 if (TREE_CODE (op
) != SSA_NAME
)
5196 /* Build a vector of case labels sorted by destination label. */
5197 ci
= XNEWVEC (struct case_info
, n
);
5198 for (idx
= 0; idx
< n
; ++idx
)
5200 ci
[idx
].expr
= gimple_switch_label (last
, idx
);
5201 ci
[idx
].bb
= label_to_block (CASE_LABEL (ci
[idx
].expr
));
5203 qsort (ci
, n
, sizeof (struct case_info
), compare_case_labels
);
5205 for (idx
= 0; idx
< n
; ++idx
)
5208 tree cl
= ci
[idx
].expr
;
5209 basic_block cbb
= ci
[idx
].bb
;
5211 min
= CASE_LOW (cl
);
5212 max
= CASE_HIGH (cl
);
5214 /* If there are multiple case labels with the same destination
5215 we need to combine them to a single value range for the edge. */
5216 if (idx
+ 1 < n
&& cbb
== ci
[idx
+ 1].bb
)
5218 /* Skip labels until the last of the group. */
5221 } while (idx
< n
&& cbb
== ci
[idx
].bb
);
5224 /* Pick up the maximum of the case label range. */
5225 if (CASE_HIGH (ci
[idx
].expr
))
5226 max
= CASE_HIGH (ci
[idx
].expr
);
5228 max
= CASE_LOW (ci
[idx
].expr
);
5231 /* Nothing to do if the range includes the default label until we
5232 can register anti-ranges. */
5233 if (min
== NULL_TREE
)
5236 /* Find the edge to register the assert expr on. */
5237 e
= find_edge (bb
, cbb
);
5239 /* Register the necessary assertions for the operand in the
5241 need_assert
|= register_edge_assert_for (op
, e
, bsi
,
5242 max
? GE_EXPR
: EQ_EXPR
,
5244 fold_convert (TREE_TYPE (op
),
5248 need_assert
|= register_edge_assert_for (op
, e
, bsi
, LE_EXPR
,
5250 fold_convert (TREE_TYPE (op
),
5260 /* Traverse all the statements in block BB looking for statements that
5261 may generate useful assertions for the SSA names in their operand.
5262 If a statement produces a useful assertion A for name N_i, then the
5263 list of assertions already generated for N_i is scanned to
5264 determine if A is actually needed.
5266 If N_i already had the assertion A at a location dominating the
5267 current location, then nothing needs to be done. Otherwise, the
5268 new location for A is recorded instead.
5270 1- For every statement S in BB, all the variables used by S are
5271 added to bitmap FOUND_IN_SUBGRAPH.
5273 2- If statement S uses an operand N in a way that exposes a known
5274 value range for N, then if N was not already generated by an
5275 ASSERT_EXPR, create a new assert location for N. For instance,
5276 if N is a pointer and the statement dereferences it, we can
5277 assume that N is not NULL.
5279 3- COND_EXPRs are a special case of #2. We can derive range
5280 information from the predicate but need to insert different
5281 ASSERT_EXPRs for each of the sub-graphs rooted at the
5282 conditional block. If the last statement of BB is a conditional
5283 expression of the form 'X op Y', then
5285 a) Remove X and Y from the set FOUND_IN_SUBGRAPH.
5287 b) If the conditional is the only entry point to the sub-graph
5288 corresponding to the THEN_CLAUSE, recurse into it. On
5289 return, if X and/or Y are marked in FOUND_IN_SUBGRAPH, then
5290 an ASSERT_EXPR is added for the corresponding variable.
5292 c) Repeat step (b) on the ELSE_CLAUSE.
5294 d) Mark X and Y in FOUND_IN_SUBGRAPH.
5303 In this case, an assertion on the THEN clause is useful to
5304 determine that 'a' is always 9 on that edge. However, an assertion
5305 on the ELSE clause would be unnecessary.
5307 4- If BB does not end in a conditional expression, then we recurse
5308 into BB's dominator children.
5310 At the end of the recursive traversal, every SSA name will have a
5311 list of locations where ASSERT_EXPRs should be added. When a new
5312 location for name N is found, it is registered by calling
5313 register_new_assert_for. That function keeps track of all the
5314 registered assertions to prevent adding unnecessary assertions.
5315 For instance, if a pointer P_4 is dereferenced more than once in a
5316 dominator tree, only the location dominating all the dereference of
5317 P_4 will receive an ASSERT_EXPR.
5319 If this function returns true, then it means that there are names
5320 for which we need to generate ASSERT_EXPRs. Those assertions are
5321 inserted by process_assert_insertions. */
5324 find_assert_locations_1 (basic_block bb
, sbitmap live
)
5326 gimple_stmt_iterator si
;
5331 need_assert
= false;
5332 last
= last_stmt (bb
);
5334 /* If BB's last statement is a conditional statement involving integer
5335 operands, determine if we need to add ASSERT_EXPRs. */
5337 && gimple_code (last
) == GIMPLE_COND
5338 && !fp_predicate (last
)
5339 && !ZERO_SSA_OPERANDS (last
, SSA_OP_USE
))
5340 need_assert
|= find_conditional_asserts (bb
, last
);
5342 /* If BB's last statement is a switch statement involving integer
5343 operands, determine if we need to add ASSERT_EXPRs. */
5345 && gimple_code (last
) == GIMPLE_SWITCH
5346 && !ZERO_SSA_OPERANDS (last
, SSA_OP_USE
))
5347 need_assert
|= find_switch_asserts (bb
, last
);
5349 /* Traverse all the statements in BB marking used names and looking
5350 for statements that may infer assertions for their used operands. */
5351 for (si
= gsi_start_bb (bb
); !gsi_end_p (si
); gsi_next (&si
))
5357 stmt
= gsi_stmt (si
);
5359 if (is_gimple_debug (stmt
))
5362 /* See if we can derive an assertion for any of STMT's operands. */
5363 FOR_EACH_SSA_TREE_OPERAND (op
, stmt
, i
, SSA_OP_USE
)
5366 enum tree_code comp_code
;
5368 /* Mark OP in our live bitmap. */
5369 SET_BIT (live
, SSA_NAME_VERSION (op
));
5371 /* If OP is used in such a way that we can infer a value
5372 range for it, and we don't find a previous assertion for
5373 it, create a new assertion location node for OP. */
5374 if (infer_value_range (stmt
, op
, &comp_code
, &value
))
5376 /* If we are able to infer a nonzero value range for OP,
5377 then walk backwards through the use-def chain to see if OP
5378 was set via a typecast.
5380 If so, then we can also infer a nonzero value range
5381 for the operand of the NOP_EXPR. */
5382 if (comp_code
== NE_EXPR
&& integer_zerop (value
))
5385 gimple def_stmt
= SSA_NAME_DEF_STMT (t
);
5387 while (is_gimple_assign (def_stmt
)
5388 && gimple_assign_rhs_code (def_stmt
) == NOP_EXPR
5390 (gimple_assign_rhs1 (def_stmt
)) == SSA_NAME
5392 (TREE_TYPE (gimple_assign_rhs1 (def_stmt
))))
5394 t
= gimple_assign_rhs1 (def_stmt
);
5395 def_stmt
= SSA_NAME_DEF_STMT (t
);
5397 /* Note we want to register the assert for the
5398 operand of the NOP_EXPR after SI, not after the
5400 if (! has_single_use (t
))
5402 register_new_assert_for (t
, t
, comp_code
, value
,
5409 /* If OP is used only once, namely in this STMT, don't
5410 bother creating an ASSERT_EXPR for it. Such an
5411 ASSERT_EXPR would do nothing but increase compile time. */
5412 if (!has_single_use (op
))
5414 register_new_assert_for (op
, op
, comp_code
, value
,
5422 /* Traverse all PHI nodes in BB marking used operands. */
5423 for (si
= gsi_start_phis (bb
); !gsi_end_p(si
); gsi_next (&si
))
5425 use_operand_p arg_p
;
5427 phi
= gsi_stmt (si
);
5429 FOR_EACH_PHI_ARG (arg_p
, phi
, i
, SSA_OP_USE
)
5431 tree arg
= USE_FROM_PTR (arg_p
);
5432 if (TREE_CODE (arg
) == SSA_NAME
)
5433 SET_BIT (live
, SSA_NAME_VERSION (arg
));
5440 /* Do an RPO walk over the function computing SSA name liveness
5441 on-the-fly and deciding on assert expressions to insert.
5442 Returns true if there are assert expressions to be inserted. */
5445 find_assert_locations (void)
5447 int *rpo
= XCNEWVEC (int, last_basic_block
+ NUM_FIXED_BLOCKS
);
5448 int *bb_rpo
= XCNEWVEC (int, last_basic_block
+ NUM_FIXED_BLOCKS
);
5449 int *last_rpo
= XCNEWVEC (int, last_basic_block
+ NUM_FIXED_BLOCKS
);
5453 live
= XCNEWVEC (sbitmap
, last_basic_block
+ NUM_FIXED_BLOCKS
);
5454 rpo_cnt
= pre_and_rev_post_order_compute (NULL
, rpo
, false);
5455 for (i
= 0; i
< rpo_cnt
; ++i
)
5458 need_asserts
= false;
5459 for (i
= rpo_cnt
-1; i
>= 0; --i
)
5461 basic_block bb
= BASIC_BLOCK (rpo
[i
]);
5467 live
[rpo
[i
]] = sbitmap_alloc (num_ssa_names
);
5468 sbitmap_zero (live
[rpo
[i
]]);
5471 /* Process BB and update the live information with uses in
5473 need_asserts
|= find_assert_locations_1 (bb
, live
[rpo
[i
]]);
5475 /* Merge liveness into the predecessor blocks and free it. */
5476 if (!sbitmap_empty_p (live
[rpo
[i
]]))
5479 FOR_EACH_EDGE (e
, ei
, bb
->preds
)
5481 int pred
= e
->src
->index
;
5482 if (e
->flags
& EDGE_DFS_BACK
)
5487 live
[pred
] = sbitmap_alloc (num_ssa_names
);
5488 sbitmap_zero (live
[pred
]);
5490 sbitmap_a_or_b (live
[pred
], live
[pred
], live
[rpo
[i
]]);
5492 if (bb_rpo
[pred
] < pred_rpo
)
5493 pred_rpo
= bb_rpo
[pred
];
5496 /* Record the RPO number of the last visited block that needs
5497 live information from this block. */
5498 last_rpo
[rpo
[i
]] = pred_rpo
;
5502 sbitmap_free (live
[rpo
[i
]]);
5503 live
[rpo
[i
]] = NULL
;
5506 /* We can free all successors live bitmaps if all their
5507 predecessors have been visited already. */
5508 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
5509 if (last_rpo
[e
->dest
->index
] == i
5510 && live
[e
->dest
->index
])
5512 sbitmap_free (live
[e
->dest
->index
]);
5513 live
[e
->dest
->index
] = NULL
;
5518 XDELETEVEC (bb_rpo
);
5519 XDELETEVEC (last_rpo
);
5520 for (i
= 0; i
< last_basic_block
+ NUM_FIXED_BLOCKS
; ++i
)
5522 sbitmap_free (live
[i
]);
5525 return need_asserts
;
5528 /* Create an ASSERT_EXPR for NAME and insert it in the location
5529 indicated by LOC. Return true if we made any edge insertions. */
5532 process_assert_insertions_for (tree name
, assert_locus_t loc
)
5534 /* Build the comparison expression NAME_i COMP_CODE VAL. */
5541 /* If we have X <=> X do not insert an assert expr for that. */
5542 if (loc
->expr
== loc
->val
)
5545 cond
= build2 (loc
->comp_code
, boolean_type_node
, loc
->expr
, loc
->val
);
5546 assert_stmt
= build_assert_expr_for (cond
, name
);
5549 /* We have been asked to insert the assertion on an edge. This
5550 is used only by COND_EXPR and SWITCH_EXPR assertions. */
5551 gcc_checking_assert (gimple_code (gsi_stmt (loc
->si
)) == GIMPLE_COND
5552 || (gimple_code (gsi_stmt (loc
->si
))
5555 gsi_insert_on_edge (loc
->e
, assert_stmt
);
5559 /* Otherwise, we can insert right after LOC->SI iff the
5560 statement must not be the last statement in the block. */
5561 stmt
= gsi_stmt (loc
->si
);
5562 if (!stmt_ends_bb_p (stmt
))
5564 gsi_insert_after (&loc
->si
, assert_stmt
, GSI_SAME_STMT
);
5568 /* If STMT must be the last statement in BB, we can only insert new
5569 assertions on the non-abnormal edge out of BB. Note that since
5570 STMT is not control flow, there may only be one non-abnormal edge
5572 FOR_EACH_EDGE (e
, ei
, loc
->bb
->succs
)
5573 if (!(e
->flags
& EDGE_ABNORMAL
))
5575 gsi_insert_on_edge (e
, assert_stmt
);
5583 /* Process all the insertions registered for every name N_i registered
5584 in NEED_ASSERT_FOR. The list of assertions to be inserted are
5585 found in ASSERTS_FOR[i]. */
5588 process_assert_insertions (void)
5592 bool update_edges_p
= false;
5593 int num_asserts
= 0;
5595 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
5596 dump_all_asserts (dump_file
);
5598 EXECUTE_IF_SET_IN_BITMAP (need_assert_for
, 0, i
, bi
)
5600 assert_locus_t loc
= asserts_for
[i
];
5605 assert_locus_t next
= loc
->next
;
5606 update_edges_p
|= process_assert_insertions_for (ssa_name (i
), loc
);
5614 gsi_commit_edge_inserts ();
5616 statistics_counter_event (cfun
, "Number of ASSERT_EXPR expressions inserted",
5621 /* Traverse the flowgraph looking for conditional jumps to insert range
5622 expressions. These range expressions are meant to provide information
5623 to optimizations that need to reason in terms of value ranges. They
5624 will not be expanded into RTL. For instance, given:
5633 this pass will transform the code into:
5639 x = ASSERT_EXPR <x, x < y>
5644 y = ASSERT_EXPR <y, x <= y>
5648 The idea is that once copy and constant propagation have run, other
5649 optimizations will be able to determine what ranges of values can 'x'
5650 take in different paths of the code, simply by checking the reaching
5651 definition of 'x'. */
5654 insert_range_assertions (void)
5656 need_assert_for
= BITMAP_ALLOC (NULL
);
5657 asserts_for
= XCNEWVEC (assert_locus_t
, num_ssa_names
);
5659 calculate_dominance_info (CDI_DOMINATORS
);
5661 if (find_assert_locations ())
5663 process_assert_insertions ();
5664 update_ssa (TODO_update_ssa_no_phi
);
5667 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
5669 fprintf (dump_file
, "\nSSA form after inserting ASSERT_EXPRs\n");
5670 dump_function_to_file (current_function_decl
, dump_file
, dump_flags
);
5674 BITMAP_FREE (need_assert_for
);
5677 /* Checks one ARRAY_REF in REF, located at LOCUS. Ignores flexible arrays
5678 and "struct" hacks. If VRP can determine that the
5679 array subscript is a constant, check if it is outside valid
5680 range. If the array subscript is a RANGE, warn if it is
5681 non-overlapping with valid range.
5682 IGNORE_OFF_BY_ONE is true if the ARRAY_REF is inside a ADDR_EXPR. */
5685 check_array_ref (location_t location
, tree ref
, bool ignore_off_by_one
)
5687 value_range_t
* vr
= NULL
;
5688 tree low_sub
, up_sub
;
5689 tree low_bound
, up_bound
, up_bound_p1
;
5692 if (TREE_NO_WARNING (ref
))
5695 low_sub
= up_sub
= TREE_OPERAND (ref
, 1);
5696 up_bound
= array_ref_up_bound (ref
);
5698 /* Can not check flexible arrays. */
5700 || TREE_CODE (up_bound
) != INTEGER_CST
)
5703 /* Accesses to trailing arrays via pointers may access storage
5704 beyond the types array bounds. */
5705 base
= get_base_address (ref
);
5706 if (base
&& TREE_CODE (base
) == MEM_REF
)
5708 tree cref
, next
= NULL_TREE
;
5710 if (TREE_CODE (TREE_OPERAND (ref
, 0)) != COMPONENT_REF
)
5713 cref
= TREE_OPERAND (ref
, 0);
5714 if (TREE_CODE (TREE_TYPE (TREE_OPERAND (cref
, 0))) == RECORD_TYPE
)
5715 for (next
= DECL_CHAIN (TREE_OPERAND (cref
, 1));
5716 next
&& TREE_CODE (next
) != FIELD_DECL
;
5717 next
= DECL_CHAIN (next
))
5720 /* If this is the last field in a struct type or a field in a
5721 union type do not warn. */
5726 low_bound
= array_ref_low_bound (ref
);
5727 up_bound_p1
= int_const_binop (PLUS_EXPR
, up_bound
, integer_one_node
);
5729 if (TREE_CODE (low_sub
) == SSA_NAME
)
5731 vr
= get_value_range (low_sub
);
5732 if (vr
->type
== VR_RANGE
|| vr
->type
== VR_ANTI_RANGE
)
5734 low_sub
= vr
->type
== VR_RANGE
? vr
->max
: vr
->min
;
5735 up_sub
= vr
->type
== VR_RANGE
? vr
->min
: vr
->max
;
5739 if (vr
&& vr
->type
== VR_ANTI_RANGE
)
5741 if (TREE_CODE (up_sub
) == INTEGER_CST
5742 && tree_int_cst_lt (up_bound
, up_sub
)
5743 && TREE_CODE (low_sub
) == INTEGER_CST
5744 && tree_int_cst_lt (low_sub
, low_bound
))
5746 warning_at (location
, OPT_Warray_bounds
,
5747 "array subscript is outside array bounds");
5748 TREE_NO_WARNING (ref
) = 1;
5751 else if (TREE_CODE (up_sub
) == INTEGER_CST
5752 && (ignore_off_by_one
5753 ? (tree_int_cst_lt (up_bound
, up_sub
)
5754 && !tree_int_cst_equal (up_bound_p1
, up_sub
))
5755 : (tree_int_cst_lt (up_bound
, up_sub
)
5756 || tree_int_cst_equal (up_bound_p1
, up_sub
))))
5758 warning_at (location
, OPT_Warray_bounds
,
5759 "array subscript is above array bounds");
5760 TREE_NO_WARNING (ref
) = 1;
5762 else if (TREE_CODE (low_sub
) == INTEGER_CST
5763 && tree_int_cst_lt (low_sub
, low_bound
))
5765 warning_at (location
, OPT_Warray_bounds
,
5766 "array subscript is below array bounds");
5767 TREE_NO_WARNING (ref
) = 1;
5771 /* Searches if the expr T, located at LOCATION computes
5772 address of an ARRAY_REF, and call check_array_ref on it. */
5775 search_for_addr_array (tree t
, location_t location
)
5777 while (TREE_CODE (t
) == SSA_NAME
)
5779 gimple g
= SSA_NAME_DEF_STMT (t
);
5781 if (gimple_code (g
) != GIMPLE_ASSIGN
)
5784 if (get_gimple_rhs_class (gimple_assign_rhs_code (g
))
5785 != GIMPLE_SINGLE_RHS
)
5788 t
= gimple_assign_rhs1 (g
);
5792 /* We are only interested in addresses of ARRAY_REF's. */
5793 if (TREE_CODE (t
) != ADDR_EXPR
)
5796 /* Check each ARRAY_REFs in the reference chain. */
5799 if (TREE_CODE (t
) == ARRAY_REF
)
5800 check_array_ref (location
, t
, true /*ignore_off_by_one*/);
5802 t
= TREE_OPERAND (t
, 0);
5804 while (handled_component_p (t
));
5806 if (TREE_CODE (t
) == MEM_REF
5807 && TREE_CODE (TREE_OPERAND (t
, 0)) == ADDR_EXPR
5808 && !TREE_NO_WARNING (t
))
5810 tree tem
= TREE_OPERAND (TREE_OPERAND (t
, 0), 0);
5811 tree low_bound
, up_bound
, el_sz
;
5813 if (TREE_CODE (TREE_TYPE (tem
)) != ARRAY_TYPE
5814 || TREE_CODE (TREE_TYPE (TREE_TYPE (tem
))) == ARRAY_TYPE
5815 || !TYPE_DOMAIN (TREE_TYPE (tem
)))
5818 low_bound
= TYPE_MIN_VALUE (TYPE_DOMAIN (TREE_TYPE (tem
)));
5819 up_bound
= TYPE_MAX_VALUE (TYPE_DOMAIN (TREE_TYPE (tem
)));
5820 el_sz
= TYPE_SIZE_UNIT (TREE_TYPE (TREE_TYPE (tem
)));
5822 || TREE_CODE (low_bound
) != INTEGER_CST
5824 || TREE_CODE (up_bound
) != INTEGER_CST
5826 || TREE_CODE (el_sz
) != INTEGER_CST
)
5829 idx
= mem_ref_offset (t
);
5830 idx
= double_int_sdiv (idx
, tree_to_double_int (el_sz
), TRUNC_DIV_EXPR
);
5831 if (double_int_scmp (idx
, double_int_zero
) < 0)
5833 warning_at (location
, OPT_Warray_bounds
,
5834 "array subscript is below array bounds");
5835 TREE_NO_WARNING (t
) = 1;
5837 else if (double_int_scmp (idx
,
5840 (tree_to_double_int (up_bound
),
5842 (tree_to_double_int (low_bound
))),
5843 double_int_one
)) > 0)
5845 warning_at (location
, OPT_Warray_bounds
,
5846 "array subscript is above array bounds");
5847 TREE_NO_WARNING (t
) = 1;
5852 /* walk_tree() callback that checks if *TP is
5853 an ARRAY_REF inside an ADDR_EXPR (in which an array
5854 subscript one outside the valid range is allowed). Call
5855 check_array_ref for each ARRAY_REF found. The location is
5859 check_array_bounds (tree
*tp
, int *walk_subtree
, void *data
)
5862 struct walk_stmt_info
*wi
= (struct walk_stmt_info
*) data
;
5863 location_t location
;
5865 if (EXPR_HAS_LOCATION (t
))
5866 location
= EXPR_LOCATION (t
);
5869 location_t
*locp
= (location_t
*) wi
->info
;
5873 *walk_subtree
= TRUE
;
5875 if (TREE_CODE (t
) == ARRAY_REF
)
5876 check_array_ref (location
, t
, false /*ignore_off_by_one*/);
5878 if (TREE_CODE (t
) == MEM_REF
5879 || (TREE_CODE (t
) == RETURN_EXPR
&& TREE_OPERAND (t
, 0)))
5880 search_for_addr_array (TREE_OPERAND (t
, 0), location
);
5882 if (TREE_CODE (t
) == ADDR_EXPR
)
5883 *walk_subtree
= FALSE
;
5888 /* Walk over all statements of all reachable BBs and call check_array_bounds
5892 check_all_array_refs (void)
5895 gimple_stmt_iterator si
;
5901 bool executable
= false;
5903 /* Skip blocks that were found to be unreachable. */
5904 FOR_EACH_EDGE (e
, ei
, bb
->preds
)
5905 executable
|= !!(e
->flags
& EDGE_EXECUTABLE
);
5909 for (si
= gsi_start_bb (bb
); !gsi_end_p (si
); gsi_next (&si
))
5911 gimple stmt
= gsi_stmt (si
);
5912 struct walk_stmt_info wi
;
5913 if (!gimple_has_location (stmt
))
5916 if (is_gimple_call (stmt
))
5919 size_t n
= gimple_call_num_args (stmt
);
5920 for (i
= 0; i
< n
; i
++)
5922 tree arg
= gimple_call_arg (stmt
, i
);
5923 search_for_addr_array (arg
, gimple_location (stmt
));
5928 memset (&wi
, 0, sizeof (wi
));
5929 wi
.info
= CONST_CAST (void *, (const void *)
5930 gimple_location_ptr (stmt
));
5932 walk_gimple_op (gsi_stmt (si
),
5940 /* Convert range assertion expressions into the implied copies and
5941 copy propagate away the copies. Doing the trivial copy propagation
5942 here avoids the need to run the full copy propagation pass after
5945 FIXME, this will eventually lead to copy propagation removing the
5946 names that had useful range information attached to them. For
5947 instance, if we had the assertion N_i = ASSERT_EXPR <N_j, N_j > 3>,
5948 then N_i will have the range [3, +INF].
5950 However, by converting the assertion into the implied copy
5951 operation N_i = N_j, we will then copy-propagate N_j into the uses
5952 of N_i and lose the range information. We may want to hold on to
5953 ASSERT_EXPRs a little while longer as the ranges could be used in
5954 things like jump threading.
5956 The problem with keeping ASSERT_EXPRs around is that passes after
5957 VRP need to handle them appropriately.
5959 Another approach would be to make the range information a first
5960 class property of the SSA_NAME so that it can be queried from
5961 any pass. This is made somewhat more complex by the need for
5962 multiple ranges to be associated with one SSA_NAME. */
5965 remove_range_assertions (void)
5968 gimple_stmt_iterator si
;
5970 /* Note that the BSI iterator bump happens at the bottom of the
5971 loop and no bump is necessary if we're removing the statement
5972 referenced by the current BSI. */
5974 for (si
= gsi_start_bb (bb
); !gsi_end_p (si
);)
5976 gimple stmt
= gsi_stmt (si
);
5979 if (is_gimple_assign (stmt
)
5980 && gimple_assign_rhs_code (stmt
) == ASSERT_EXPR
)
5982 tree rhs
= gimple_assign_rhs1 (stmt
);
5984 tree cond
= fold (ASSERT_EXPR_COND (rhs
));
5985 use_operand_p use_p
;
5986 imm_use_iterator iter
;
5988 gcc_assert (cond
!= boolean_false_node
);
5990 /* Propagate the RHS into every use of the LHS. */
5991 var
= ASSERT_EXPR_VAR (rhs
);
5992 FOR_EACH_IMM_USE_STMT (use_stmt
, iter
,
5993 gimple_assign_lhs (stmt
))
5994 FOR_EACH_IMM_USE_ON_STMT (use_p
, iter
)
5996 SET_USE (use_p
, var
);
5997 gcc_assert (TREE_CODE (var
) == SSA_NAME
);
6000 /* And finally, remove the copy, it is not needed. */
6001 gsi_remove (&si
, true);
6002 release_defs (stmt
);
6010 /* Return true if STMT is interesting for VRP. */
6013 stmt_interesting_for_vrp (gimple stmt
)
6015 if (gimple_code (stmt
) == GIMPLE_PHI
6016 && is_gimple_reg (gimple_phi_result (stmt
))
6017 && (INTEGRAL_TYPE_P (TREE_TYPE (gimple_phi_result (stmt
)))
6018 || POINTER_TYPE_P (TREE_TYPE (gimple_phi_result (stmt
)))))
6020 else if (is_gimple_assign (stmt
) || is_gimple_call (stmt
))
6022 tree lhs
= gimple_get_lhs (stmt
);
6024 /* In general, assignments with virtual operands are not useful
6025 for deriving ranges, with the obvious exception of calls to
6026 builtin functions. */
6027 if (lhs
&& TREE_CODE (lhs
) == SSA_NAME
6028 && (INTEGRAL_TYPE_P (TREE_TYPE (lhs
))
6029 || POINTER_TYPE_P (TREE_TYPE (lhs
)))
6030 && ((is_gimple_call (stmt
)
6031 && gimple_call_fndecl (stmt
) != NULL_TREE
6032 && DECL_BUILT_IN (gimple_call_fndecl (stmt
)))
6033 || !gimple_vuse (stmt
)))
6036 else if (gimple_code (stmt
) == GIMPLE_COND
6037 || gimple_code (stmt
) == GIMPLE_SWITCH
)
6044 /* Initialize local data structures for VRP. */
6047 vrp_initialize (void)
6051 values_propagated
= false;
6052 num_vr_values
= num_ssa_names
;
6053 vr_value
= XCNEWVEC (value_range_t
*, num_vr_values
);
6054 vr_phi_edge_counts
= XCNEWVEC (int, num_ssa_names
);
6058 gimple_stmt_iterator si
;
6060 for (si
= gsi_start_phis (bb
); !gsi_end_p (si
); gsi_next (&si
))
6062 gimple phi
= gsi_stmt (si
);
6063 if (!stmt_interesting_for_vrp (phi
))
6065 tree lhs
= PHI_RESULT (phi
);
6066 set_value_range_to_varying (get_value_range (lhs
));
6067 prop_set_simulate_again (phi
, false);
6070 prop_set_simulate_again (phi
, true);
6073 for (si
= gsi_start_bb (bb
); !gsi_end_p (si
); gsi_next (&si
))
6075 gimple stmt
= gsi_stmt (si
);
6077 /* If the statement is a control insn, then we do not
6078 want to avoid simulating the statement once. Failure
6079 to do so means that those edges will never get added. */
6080 if (stmt_ends_bb_p (stmt
))
6081 prop_set_simulate_again (stmt
, true);
6082 else if (!stmt_interesting_for_vrp (stmt
))
6086 FOR_EACH_SSA_TREE_OPERAND (def
, stmt
, i
, SSA_OP_DEF
)
6087 set_value_range_to_varying (get_value_range (def
));
6088 prop_set_simulate_again (stmt
, false);
6091 prop_set_simulate_again (stmt
, true);
6096 /* Return the singleton value-range for NAME or NAME. */
6099 vrp_valueize (tree name
)
6101 if (TREE_CODE (name
) == SSA_NAME
)
6103 value_range_t
*vr
= get_value_range (name
);
6104 if (vr
->type
== VR_RANGE
6105 && (vr
->min
== vr
->max
6106 || operand_equal_p (vr
->min
, vr
->max
, 0)))
6112 /* Visit assignment STMT. If it produces an interesting range, record
6113 the SSA name in *OUTPUT_P. */
6115 static enum ssa_prop_result
6116 vrp_visit_assignment_or_call (gimple stmt
, tree
*output_p
)
6120 enum gimple_code code
= gimple_code (stmt
);
6121 lhs
= gimple_get_lhs (stmt
);
6123 /* We only keep track of ranges in integral and pointer types. */
6124 if (TREE_CODE (lhs
) == SSA_NAME
6125 && ((INTEGRAL_TYPE_P (TREE_TYPE (lhs
))
6126 /* It is valid to have NULL MIN/MAX values on a type. See
6127 build_range_type. */
6128 && TYPE_MIN_VALUE (TREE_TYPE (lhs
))
6129 && TYPE_MAX_VALUE (TREE_TYPE (lhs
)))
6130 || POINTER_TYPE_P (TREE_TYPE (lhs
))))
6132 value_range_t new_vr
= VR_INITIALIZER
;
6134 /* Try folding the statement to a constant first. */
6135 tree tem
= gimple_fold_stmt_to_constant (stmt
, vrp_valueize
);
6136 if (tem
&& !is_overflow_infinity (tem
))
6137 set_value_range (&new_vr
, VR_RANGE
, tem
, tem
, NULL
);
6138 /* Then dispatch to value-range extracting functions. */
6139 else if (code
== GIMPLE_CALL
)
6140 extract_range_basic (&new_vr
, stmt
);
6142 extract_range_from_assignment (&new_vr
, stmt
);
6144 if (update_value_range (lhs
, &new_vr
))
6148 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
6150 fprintf (dump_file
, "Found new range for ");
6151 print_generic_expr (dump_file
, lhs
, 0);
6152 fprintf (dump_file
, ": ");
6153 dump_value_range (dump_file
, &new_vr
);
6154 fprintf (dump_file
, "\n\n");
6157 if (new_vr
.type
== VR_VARYING
)
6158 return SSA_PROP_VARYING
;
6160 return SSA_PROP_INTERESTING
;
6163 return SSA_PROP_NOT_INTERESTING
;
6166 /* Every other statement produces no useful ranges. */
6167 FOR_EACH_SSA_TREE_OPERAND (def
, stmt
, iter
, SSA_OP_DEF
)
6168 set_value_range_to_varying (get_value_range (def
));
6170 return SSA_PROP_VARYING
;
6173 /* Helper that gets the value range of the SSA_NAME with version I
6174 or a symbolic range containing the SSA_NAME only if the value range
6175 is varying or undefined. */
6177 static inline value_range_t
6178 get_vr_for_comparison (int i
)
6180 value_range_t vr
= *get_value_range (ssa_name (i
));
6182 /* If name N_i does not have a valid range, use N_i as its own
6183 range. This allows us to compare against names that may
6184 have N_i in their ranges. */
6185 if (vr
.type
== VR_VARYING
|| vr
.type
== VR_UNDEFINED
)
6188 vr
.min
= ssa_name (i
);
6189 vr
.max
= ssa_name (i
);
6195 /* Compare all the value ranges for names equivalent to VAR with VAL
6196 using comparison code COMP. Return the same value returned by
6197 compare_range_with_value, including the setting of
6198 *STRICT_OVERFLOW_P. */
6201 compare_name_with_value (enum tree_code comp
, tree var
, tree val
,
6202 bool *strict_overflow_p
)
6208 int used_strict_overflow
;
6210 value_range_t equiv_vr
;
6212 /* Get the set of equivalences for VAR. */
6213 e
= get_value_range (var
)->equiv
;
6215 /* Start at -1. Set it to 0 if we do a comparison without relying
6216 on overflow, or 1 if all comparisons rely on overflow. */
6217 used_strict_overflow
= -1;
6219 /* Compare vars' value range with val. */
6220 equiv_vr
= get_vr_for_comparison (SSA_NAME_VERSION (var
));
6222 retval
= compare_range_with_value (comp
, &equiv_vr
, val
, &sop
);
6224 used_strict_overflow
= sop
? 1 : 0;
6226 /* If the equiv set is empty we have done all work we need to do. */
6230 && used_strict_overflow
> 0)
6231 *strict_overflow_p
= true;
6235 EXECUTE_IF_SET_IN_BITMAP (e
, 0, i
, bi
)
6237 equiv_vr
= get_vr_for_comparison (i
);
6239 t
= compare_range_with_value (comp
, &equiv_vr
, val
, &sop
);
6242 /* If we get different answers from different members
6243 of the equivalence set this check must be in a dead
6244 code region. Folding it to a trap representation
6245 would be correct here. For now just return don't-know. */
6255 used_strict_overflow
= 0;
6256 else if (used_strict_overflow
< 0)
6257 used_strict_overflow
= 1;
6262 && used_strict_overflow
> 0)
6263 *strict_overflow_p
= true;
6269 /* Given a comparison code COMP and names N1 and N2, compare all the
6270 ranges equivalent to N1 against all the ranges equivalent to N2
6271 to determine the value of N1 COMP N2. Return the same value
6272 returned by compare_ranges. Set *STRICT_OVERFLOW_P to indicate
6273 whether we relied on an overflow infinity in the comparison. */
6277 compare_names (enum tree_code comp
, tree n1
, tree n2
,
6278 bool *strict_overflow_p
)
6282 bitmap_iterator bi1
, bi2
;
6284 int used_strict_overflow
;
6285 static bitmap_obstack
*s_obstack
= NULL
;
6286 static bitmap s_e1
= NULL
, s_e2
= NULL
;
6288 /* Compare the ranges of every name equivalent to N1 against the
6289 ranges of every name equivalent to N2. */
6290 e1
= get_value_range (n1
)->equiv
;
6291 e2
= get_value_range (n2
)->equiv
;
6293 /* Use the fake bitmaps if e1 or e2 are not available. */
6294 if (s_obstack
== NULL
)
6296 s_obstack
= XNEW (bitmap_obstack
);
6297 bitmap_obstack_initialize (s_obstack
);
6298 s_e1
= BITMAP_ALLOC (s_obstack
);
6299 s_e2
= BITMAP_ALLOC (s_obstack
);
6306 /* Add N1 and N2 to their own set of equivalences to avoid
6307 duplicating the body of the loop just to check N1 and N2
6309 bitmap_set_bit (e1
, SSA_NAME_VERSION (n1
));
6310 bitmap_set_bit (e2
, SSA_NAME_VERSION (n2
));
6312 /* If the equivalence sets have a common intersection, then the two
6313 names can be compared without checking their ranges. */
6314 if (bitmap_intersect_p (e1
, e2
))
6316 bitmap_clear_bit (e1
, SSA_NAME_VERSION (n1
));
6317 bitmap_clear_bit (e2
, SSA_NAME_VERSION (n2
));
6319 return (comp
== EQ_EXPR
|| comp
== GE_EXPR
|| comp
== LE_EXPR
)
6321 : boolean_false_node
;
6324 /* Start at -1. Set it to 0 if we do a comparison without relying
6325 on overflow, or 1 if all comparisons rely on overflow. */
6326 used_strict_overflow
= -1;
6328 /* Otherwise, compare all the equivalent ranges. First, add N1 and
6329 N2 to their own set of equivalences to avoid duplicating the body
6330 of the loop just to check N1 and N2 ranges. */
6331 EXECUTE_IF_SET_IN_BITMAP (e1
, 0, i1
, bi1
)
6333 value_range_t vr1
= get_vr_for_comparison (i1
);
6335 t
= retval
= NULL_TREE
;
6336 EXECUTE_IF_SET_IN_BITMAP (e2
, 0, i2
, bi2
)
6340 value_range_t vr2
= get_vr_for_comparison (i2
);
6342 t
= compare_ranges (comp
, &vr1
, &vr2
, &sop
);
6345 /* If we get different answers from different members
6346 of the equivalence set this check must be in a dead
6347 code region. Folding it to a trap representation
6348 would be correct here. For now just return don't-know. */
6352 bitmap_clear_bit (e1
, SSA_NAME_VERSION (n1
));
6353 bitmap_clear_bit (e2
, SSA_NAME_VERSION (n2
));
6359 used_strict_overflow
= 0;
6360 else if (used_strict_overflow
< 0)
6361 used_strict_overflow
= 1;
6367 bitmap_clear_bit (e1
, SSA_NAME_VERSION (n1
));
6368 bitmap_clear_bit (e2
, SSA_NAME_VERSION (n2
));
6369 if (used_strict_overflow
> 0)
6370 *strict_overflow_p
= true;
6375 /* None of the equivalent ranges are useful in computing this
6377 bitmap_clear_bit (e1
, SSA_NAME_VERSION (n1
));
6378 bitmap_clear_bit (e2
, SSA_NAME_VERSION (n2
));
6382 /* Helper function for vrp_evaluate_conditional_warnv. */
6385 vrp_evaluate_conditional_warnv_with_ops_using_ranges (enum tree_code code
,
6387 bool * strict_overflow_p
)
6389 value_range_t
*vr0
, *vr1
;
6391 vr0
= (TREE_CODE (op0
) == SSA_NAME
) ? get_value_range (op0
) : NULL
;
6392 vr1
= (TREE_CODE (op1
) == SSA_NAME
) ? get_value_range (op1
) : NULL
;
6395 return compare_ranges (code
, vr0
, vr1
, strict_overflow_p
);
6396 else if (vr0
&& vr1
== NULL
)
6397 return compare_range_with_value (code
, vr0
, op1
, strict_overflow_p
);
6398 else if (vr0
== NULL
&& vr1
)
6399 return (compare_range_with_value
6400 (swap_tree_comparison (code
), vr1
, op0
, strict_overflow_p
));
6404 /* Helper function for vrp_evaluate_conditional_warnv. */
6407 vrp_evaluate_conditional_warnv_with_ops (enum tree_code code
, tree op0
,
6408 tree op1
, bool use_equiv_p
,
6409 bool *strict_overflow_p
, bool *only_ranges
)
6413 *only_ranges
= true;
6415 /* We only deal with integral and pointer types. */
6416 if (!INTEGRAL_TYPE_P (TREE_TYPE (op0
))
6417 && !POINTER_TYPE_P (TREE_TYPE (op0
)))
6423 && (ret
= vrp_evaluate_conditional_warnv_with_ops_using_ranges
6424 (code
, op0
, op1
, strict_overflow_p
)))
6426 *only_ranges
= false;
6427 if (TREE_CODE (op0
) == SSA_NAME
&& TREE_CODE (op1
) == SSA_NAME
)
6428 return compare_names (code
, op0
, op1
, strict_overflow_p
);
6429 else if (TREE_CODE (op0
) == SSA_NAME
)
6430 return compare_name_with_value (code
, op0
, op1
, strict_overflow_p
);
6431 else if (TREE_CODE (op1
) == SSA_NAME
)
6432 return (compare_name_with_value
6433 (swap_tree_comparison (code
), op1
, op0
, strict_overflow_p
));
6436 return vrp_evaluate_conditional_warnv_with_ops_using_ranges (code
, op0
, op1
,
6441 /* Given (CODE OP0 OP1) within STMT, try to simplify it based on value range
6442 information. Return NULL if the conditional can not be evaluated.
6443 The ranges of all the names equivalent with the operands in COND
6444 will be used when trying to compute the value. If the result is
6445 based on undefined signed overflow, issue a warning if
6449 vrp_evaluate_conditional (enum tree_code code
, tree op0
, tree op1
, gimple stmt
)
6455 /* Some passes and foldings leak constants with overflow flag set
6456 into the IL. Avoid doing wrong things with these and bail out. */
6457 if ((TREE_CODE (op0
) == INTEGER_CST
6458 && TREE_OVERFLOW (op0
))
6459 || (TREE_CODE (op1
) == INTEGER_CST
6460 && TREE_OVERFLOW (op1
)))
6464 ret
= vrp_evaluate_conditional_warnv_with_ops (code
, op0
, op1
, true, &sop
,
6469 enum warn_strict_overflow_code wc
;
6470 const char* warnmsg
;
6472 if (is_gimple_min_invariant (ret
))
6474 wc
= WARN_STRICT_OVERFLOW_CONDITIONAL
;
6475 warnmsg
= G_("assuming signed overflow does not occur when "
6476 "simplifying conditional to constant");
6480 wc
= WARN_STRICT_OVERFLOW_COMPARISON
;
6481 warnmsg
= G_("assuming signed overflow does not occur when "
6482 "simplifying conditional");
6485 if (issue_strict_overflow_warning (wc
))
6487 location_t location
;
6489 if (!gimple_has_location (stmt
))
6490 location
= input_location
;
6492 location
= gimple_location (stmt
);
6493 warning_at (location
, OPT_Wstrict_overflow
, "%s", warnmsg
);
6497 if (warn_type_limits
6498 && ret
&& only_ranges
6499 && TREE_CODE_CLASS (code
) == tcc_comparison
6500 && TREE_CODE (op0
) == SSA_NAME
)
6502 /* If the comparison is being folded and the operand on the LHS
6503 is being compared against a constant value that is outside of
6504 the natural range of OP0's type, then the predicate will
6505 always fold regardless of the value of OP0. If -Wtype-limits
6506 was specified, emit a warning. */
6507 tree type
= TREE_TYPE (op0
);
6508 value_range_t
*vr0
= get_value_range (op0
);
6510 if (vr0
->type
!= VR_VARYING
6511 && INTEGRAL_TYPE_P (type
)
6512 && vrp_val_is_min (vr0
->min
)
6513 && vrp_val_is_max (vr0
->max
)
6514 && is_gimple_min_invariant (op1
))
6516 location_t location
;
6518 if (!gimple_has_location (stmt
))
6519 location
= input_location
;
6521 location
= gimple_location (stmt
);
6523 warning_at (location
, OPT_Wtype_limits
,
6525 ? G_("comparison always false "
6526 "due to limited range of data type")
6527 : G_("comparison always true "
6528 "due to limited range of data type"));
6536 /* Visit conditional statement STMT. If we can determine which edge
6537 will be taken out of STMT's basic block, record it in
6538 *TAKEN_EDGE_P and return SSA_PROP_INTERESTING. Otherwise, return
6539 SSA_PROP_VARYING. */
6541 static enum ssa_prop_result
6542 vrp_visit_cond_stmt (gimple stmt
, edge
*taken_edge_p
)
6547 *taken_edge_p
= NULL
;
6549 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
6554 fprintf (dump_file
, "\nVisiting conditional with predicate: ");
6555 print_gimple_stmt (dump_file
, stmt
, 0, 0);
6556 fprintf (dump_file
, "\nWith known ranges\n");
6558 FOR_EACH_SSA_TREE_OPERAND (use
, stmt
, i
, SSA_OP_USE
)
6560 fprintf (dump_file
, "\t");
6561 print_generic_expr (dump_file
, use
, 0);
6562 fprintf (dump_file
, ": ");
6563 dump_value_range (dump_file
, vr_value
[SSA_NAME_VERSION (use
)]);
6566 fprintf (dump_file
, "\n");
6569 /* Compute the value of the predicate COND by checking the known
6570 ranges of each of its operands.
6572 Note that we cannot evaluate all the equivalent ranges here
6573 because those ranges may not yet be final and with the current
6574 propagation strategy, we cannot determine when the value ranges
6575 of the names in the equivalence set have changed.
6577 For instance, given the following code fragment
6581 i_14 = ASSERT_EXPR <i_5, i_5 != 0>
6585 Assume that on the first visit to i_14, i_5 has the temporary
6586 range [8, 8] because the second argument to the PHI function is
6587 not yet executable. We derive the range ~[0, 0] for i_14 and the
6588 equivalence set { i_5 }. So, when we visit 'if (i_14 == 1)' for
6589 the first time, since i_14 is equivalent to the range [8, 8], we
6590 determine that the predicate is always false.
6592 On the next round of propagation, i_13 is determined to be
6593 VARYING, which causes i_5 to drop down to VARYING. So, another
6594 visit to i_14 is scheduled. In this second visit, we compute the
6595 exact same range and equivalence set for i_14, namely ~[0, 0] and
6596 { i_5 }. But we did not have the previous range for i_5
6597 registered, so vrp_visit_assignment thinks that the range for
6598 i_14 has not changed. Therefore, the predicate 'if (i_14 == 1)'
6599 is not visited again, which stops propagation from visiting
6600 statements in the THEN clause of that if().
6602 To properly fix this we would need to keep the previous range
6603 value for the names in the equivalence set. This way we would've
6604 discovered that from one visit to the other i_5 changed from
6605 range [8, 8] to VR_VARYING.
6607 However, fixing this apparent limitation may not be worth the
6608 additional checking. Testing on several code bases (GCC, DLV,
6609 MICO, TRAMP3D and SPEC2000) showed that doing this results in
6610 4 more predicates folded in SPEC. */
6613 val
= vrp_evaluate_conditional_warnv_with_ops (gimple_cond_code (stmt
),
6614 gimple_cond_lhs (stmt
),
6615 gimple_cond_rhs (stmt
),
6620 *taken_edge_p
= find_taken_edge (gimple_bb (stmt
), val
);
6623 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
6625 "\nIgnoring predicate evaluation because "
6626 "it assumes that signed overflow is undefined");
6631 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
6633 fprintf (dump_file
, "\nPredicate evaluates to: ");
6634 if (val
== NULL_TREE
)
6635 fprintf (dump_file
, "DON'T KNOW\n");
6637 print_generic_stmt (dump_file
, val
, 0);
6640 return (*taken_edge_p
) ? SSA_PROP_INTERESTING
: SSA_PROP_VARYING
;
6643 /* Searches the case label vector VEC for the index *IDX of the CASE_LABEL
6644 that includes the value VAL. The search is restricted to the range
6645 [START_IDX, n - 1] where n is the size of VEC.
6647 If there is a CASE_LABEL for VAL, its index is placed in IDX and true is
6650 If there is no CASE_LABEL for VAL and there is one that is larger than VAL,
6651 it is placed in IDX and false is returned.
6653 If VAL is larger than any CASE_LABEL, n is placed on IDX and false is
6657 find_case_label_index (gimple stmt
, size_t start_idx
, tree val
, size_t *idx
)
6659 size_t n
= gimple_switch_num_labels (stmt
);
6662 /* Find case label for minimum of the value range or the next one.
6663 At each iteration we are searching in [low, high - 1]. */
6665 for (low
= start_idx
, high
= n
; high
!= low
; )
6669 /* Note that i != high, so we never ask for n. */
6670 size_t i
= (high
+ low
) / 2;
6671 t
= gimple_switch_label (stmt
, i
);
6673 /* Cache the result of comparing CASE_LOW and val. */
6674 cmp
= tree_int_cst_compare (CASE_LOW (t
), val
);
6678 /* Ranges cannot be empty. */
6687 if (CASE_HIGH (t
) != NULL
6688 && tree_int_cst_compare (CASE_HIGH (t
), val
) >= 0)
6700 /* Searches the case label vector VEC for the range of CASE_LABELs that is used
6701 for values between MIN and MAX. The first index is placed in MIN_IDX. The
6702 last index is placed in MAX_IDX. If the range of CASE_LABELs is empty
6703 then MAX_IDX < MIN_IDX.
6704 Returns true if the default label is not needed. */
6707 find_case_label_range (gimple stmt
, tree min
, tree max
, size_t *min_idx
,
6711 bool min_take_default
= !find_case_label_index (stmt
, 1, min
, &i
);
6712 bool max_take_default
= !find_case_label_index (stmt
, i
, max
, &j
);
6716 && max_take_default
)
6718 /* Only the default case label reached.
6719 Return an empty range. */
6726 bool take_default
= min_take_default
|| max_take_default
;
6730 if (max_take_default
)
6733 /* If the case label range is continuous, we do not need
6734 the default case label. Verify that. */
6735 high
= CASE_LOW (gimple_switch_label (stmt
, i
));
6736 if (CASE_HIGH (gimple_switch_label (stmt
, i
)))
6737 high
= CASE_HIGH (gimple_switch_label (stmt
, i
));
6738 for (k
= i
+ 1; k
<= j
; ++k
)
6740 low
= CASE_LOW (gimple_switch_label (stmt
, k
));
6741 if (!integer_onep (int_const_binop (MINUS_EXPR
, low
, high
)))
6743 take_default
= true;
6747 if (CASE_HIGH (gimple_switch_label (stmt
, k
)))
6748 high
= CASE_HIGH (gimple_switch_label (stmt
, k
));
6753 return !take_default
;
6757 /* Visit switch statement STMT. If we can determine which edge
6758 will be taken out of STMT's basic block, record it in
6759 *TAKEN_EDGE_P and return SSA_PROP_INTERESTING. Otherwise, return
6760 SSA_PROP_VARYING. */
6762 static enum ssa_prop_result
6763 vrp_visit_switch_stmt (gimple stmt
, edge
*taken_edge_p
)
6767 size_t i
= 0, j
= 0;
6770 *taken_edge_p
= NULL
;
6771 op
= gimple_switch_index (stmt
);
6772 if (TREE_CODE (op
) != SSA_NAME
)
6773 return SSA_PROP_VARYING
;
6775 vr
= get_value_range (op
);
6776 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
6778 fprintf (dump_file
, "\nVisiting switch expression with operand ");
6779 print_generic_expr (dump_file
, op
, 0);
6780 fprintf (dump_file
, " with known range ");
6781 dump_value_range (dump_file
, vr
);
6782 fprintf (dump_file
, "\n");
6785 if (vr
->type
!= VR_RANGE
6786 || symbolic_range_p (vr
))
6787 return SSA_PROP_VARYING
;
6789 /* Find the single edge that is taken from the switch expression. */
6790 take_default
= !find_case_label_range (stmt
, vr
->min
, vr
->max
, &i
, &j
);
6792 /* Check if the range spans no CASE_LABEL. If so, we only reach the default
6796 gcc_assert (take_default
);
6797 val
= gimple_switch_default_label (stmt
);
6801 /* Check if labels with index i to j and maybe the default label
6802 are all reaching the same label. */
6804 val
= gimple_switch_label (stmt
, i
);
6806 && CASE_LABEL (gimple_switch_default_label (stmt
))
6807 != CASE_LABEL (val
))
6809 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
6810 fprintf (dump_file
, " not a single destination for this "
6812 return SSA_PROP_VARYING
;
6814 for (++i
; i
<= j
; ++i
)
6816 if (CASE_LABEL (gimple_switch_label (stmt
, i
)) != CASE_LABEL (val
))
6818 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
6819 fprintf (dump_file
, " not a single destination for this "
6821 return SSA_PROP_VARYING
;
6826 *taken_edge_p
= find_edge (gimple_bb (stmt
),
6827 label_to_block (CASE_LABEL (val
)));
6829 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
6831 fprintf (dump_file
, " will take edge to ");
6832 print_generic_stmt (dump_file
, CASE_LABEL (val
), 0);
6835 return SSA_PROP_INTERESTING
;
6839 /* Evaluate statement STMT. If the statement produces a useful range,
6840 return SSA_PROP_INTERESTING and record the SSA name with the
6841 interesting range into *OUTPUT_P.
6843 If STMT is a conditional branch and we can determine its truth
6844 value, the taken edge is recorded in *TAKEN_EDGE_P.
6846 If STMT produces a varying value, return SSA_PROP_VARYING. */
6848 static enum ssa_prop_result
6849 vrp_visit_stmt (gimple stmt
, edge
*taken_edge_p
, tree
*output_p
)
6854 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
6856 fprintf (dump_file
, "\nVisiting statement:\n");
6857 print_gimple_stmt (dump_file
, stmt
, 0, dump_flags
);
6858 fprintf (dump_file
, "\n");
6861 if (!stmt_interesting_for_vrp (stmt
))
6862 gcc_assert (stmt_ends_bb_p (stmt
));
6863 else if (is_gimple_assign (stmt
) || is_gimple_call (stmt
))
6865 /* In general, assignments with virtual operands are not useful
6866 for deriving ranges, with the obvious exception of calls to
6867 builtin functions. */
6868 if ((is_gimple_call (stmt
)
6869 && gimple_call_fndecl (stmt
) != NULL_TREE
6870 && DECL_BUILT_IN (gimple_call_fndecl (stmt
)))
6871 || !gimple_vuse (stmt
))
6872 return vrp_visit_assignment_or_call (stmt
, output_p
);
6874 else if (gimple_code (stmt
) == GIMPLE_COND
)
6875 return vrp_visit_cond_stmt (stmt
, taken_edge_p
);
6876 else if (gimple_code (stmt
) == GIMPLE_SWITCH
)
6877 return vrp_visit_switch_stmt (stmt
, taken_edge_p
);
6879 /* All other statements produce nothing of interest for VRP, so mark
6880 their outputs varying and prevent further simulation. */
6881 FOR_EACH_SSA_TREE_OPERAND (def
, stmt
, iter
, SSA_OP_DEF
)
6882 set_value_range_to_varying (get_value_range (def
));
6884 return SSA_PROP_VARYING
;
6887 /* Union the two value-ranges { *VR0TYPE, *VR0MIN, *VR0MAX } and
6888 { VR1TYPE, VR0MIN, VR0MAX } and store the result
6889 in { *VR0TYPE, *VR0MIN, *VR0MAX }. This may not be the smallest
6890 possible such range. The resulting range is not canonicalized. */
6893 union_ranges (enum value_range_type
*vr0type
,
6894 tree
*vr0min
, tree
*vr0max
,
6895 enum value_range_type vr1type
,
6896 tree vr1min
, tree vr1max
)
6898 bool mineq
= operand_equal_p (*vr0min
, vr1min
, 0);
6899 bool maxeq
= operand_equal_p (*vr0max
, vr1max
, 0);
6901 /* [] is vr0, () is vr1 in the following classification comments. */
6905 if (*vr0type
== vr1type
)
6906 /* Nothing to do for equal ranges. */
6908 else if ((*vr0type
== VR_RANGE
6909 && vr1type
== VR_ANTI_RANGE
)
6910 || (*vr0type
== VR_ANTI_RANGE
6911 && vr1type
== VR_RANGE
))
6913 /* For anti-range with range union the result is varying. */
6919 else if (operand_less_p (*vr0max
, vr1min
) == 1
6920 || operand_less_p (vr1max
, *vr0min
) == 1)
6922 /* [ ] ( ) or ( ) [ ]
6923 If the ranges have an empty intersection, result of the union
6924 operation is the anti-range or if both are anti-ranges
6926 if (*vr0type
== VR_ANTI_RANGE
6927 && vr1type
== VR_ANTI_RANGE
)
6929 else if (*vr0type
== VR_ANTI_RANGE
6930 && vr1type
== VR_RANGE
)
6932 else if (*vr0type
== VR_RANGE
6933 && vr1type
== VR_ANTI_RANGE
)
6939 else if (*vr0type
== VR_RANGE
6940 && vr1type
== VR_RANGE
)
6942 /* The result is the convex hull of both ranges. */
6943 if (operand_less_p (*vr0max
, vr1min
) == 1)
6945 /* If the result can be an anti-range, create one. */
6946 if (TREE_CODE (*vr0max
) == INTEGER_CST
6947 && TREE_CODE (vr1min
) == INTEGER_CST
6948 && vrp_val_is_min (*vr0min
)
6949 && vrp_val_is_max (vr1max
))
6951 tree min
= int_const_binop (PLUS_EXPR
,
6952 *vr0max
, integer_one_node
);
6953 tree max
= int_const_binop (MINUS_EXPR
,
6954 vr1min
, integer_one_node
);
6955 if (!operand_less_p (max
, min
))
6957 *vr0type
= VR_ANTI_RANGE
;
6969 /* If the result can be an anti-range, create one. */
6970 if (TREE_CODE (vr1max
) == INTEGER_CST
6971 && TREE_CODE (*vr0min
) == INTEGER_CST
6972 && vrp_val_is_min (vr1min
)
6973 && vrp_val_is_max (*vr0max
))
6975 tree min
= int_const_binop (PLUS_EXPR
,
6976 vr1max
, integer_one_node
);
6977 tree max
= int_const_binop (MINUS_EXPR
,
6978 *vr0min
, integer_one_node
);
6979 if (!operand_less_p (max
, min
))
6981 *vr0type
= VR_ANTI_RANGE
;
6995 else if ((maxeq
|| operand_less_p (vr1max
, *vr0max
) == 1)
6996 && (mineq
|| operand_less_p (*vr0min
, vr1min
) == 1))
6998 /* [ ( ) ] or [( ) ] or [ ( )] */
6999 if (*vr0type
== VR_RANGE
7000 && vr1type
== VR_RANGE
)
7002 else if (*vr0type
== VR_ANTI_RANGE
7003 && vr1type
== VR_ANTI_RANGE
)
7009 else if (*vr0type
== VR_ANTI_RANGE
7010 && vr1type
== VR_RANGE
)
7012 /* Arbitrarily choose the right or left gap. */
7013 if (!mineq
&& TREE_CODE (vr1min
) == INTEGER_CST
)
7014 *vr0max
= int_const_binop (MINUS_EXPR
, vr1min
, integer_one_node
);
7015 else if (!maxeq
&& TREE_CODE (vr1max
) == INTEGER_CST
)
7016 *vr0min
= int_const_binop (PLUS_EXPR
, vr1max
, integer_one_node
);
7020 else if (*vr0type
== VR_RANGE
7021 && vr1type
== VR_ANTI_RANGE
)
7022 /* The result covers everything. */
7027 else if ((maxeq
|| operand_less_p (*vr0max
, vr1max
) == 1)
7028 && (mineq
|| operand_less_p (vr1min
, *vr0min
) == 1))
7030 /* ( [ ] ) or ([ ] ) or ( [ ]) */
7031 if (*vr0type
== VR_RANGE
7032 && vr1type
== VR_RANGE
)
7038 else if (*vr0type
== VR_ANTI_RANGE
7039 && vr1type
== VR_ANTI_RANGE
)
7041 else if (*vr0type
== VR_RANGE
7042 && vr1type
== VR_ANTI_RANGE
)
7044 *vr0type
= VR_ANTI_RANGE
;
7045 if (!mineq
&& TREE_CODE (*vr0min
) == INTEGER_CST
)
7047 *vr0max
= int_const_binop (MINUS_EXPR
, *vr0min
, integer_one_node
);
7050 else if (!maxeq
&& TREE_CODE (*vr0max
) == INTEGER_CST
)
7052 *vr0min
= int_const_binop (PLUS_EXPR
, *vr0max
, integer_one_node
);
7058 else if (*vr0type
== VR_ANTI_RANGE
7059 && vr1type
== VR_RANGE
)
7060 /* The result covers everything. */
7065 else if ((operand_less_p (vr1min
, *vr0max
) == 1
7066 || operand_equal_p (vr1min
, *vr0max
, 0))
7067 && operand_less_p (*vr0min
, vr1min
) == 1)
7069 /* [ ( ] ) or [ ]( ) */
7070 if (*vr0type
== VR_RANGE
7071 && vr1type
== VR_RANGE
)
7073 else if (*vr0type
== VR_ANTI_RANGE
7074 && vr1type
== VR_ANTI_RANGE
)
7076 else if (*vr0type
== VR_ANTI_RANGE
7077 && vr1type
== VR_RANGE
)
7079 if (TREE_CODE (vr1min
) == INTEGER_CST
)
7080 *vr0max
= int_const_binop (MINUS_EXPR
, vr1min
, integer_one_node
);
7084 else if (*vr0type
== VR_RANGE
7085 && vr1type
== VR_ANTI_RANGE
)
7087 if (TREE_CODE (*vr0max
) == INTEGER_CST
)
7090 *vr0min
= int_const_binop (PLUS_EXPR
, *vr0max
, integer_one_node
);
7099 else if ((operand_less_p (*vr0min
, vr1max
) == 1
7100 || operand_equal_p (*vr0min
, vr1max
, 0))
7101 && operand_less_p (vr1min
, *vr0min
) == 1)
7103 /* ( [ ) ] or ( )[ ] */
7104 if (*vr0type
== VR_RANGE
7105 && vr1type
== VR_RANGE
)
7107 else if (*vr0type
== VR_ANTI_RANGE
7108 && vr1type
== VR_ANTI_RANGE
)
7110 else if (*vr0type
== VR_ANTI_RANGE
7111 && vr1type
== VR_RANGE
)
7113 if (TREE_CODE (vr1max
) == INTEGER_CST
)
7114 *vr0min
= int_const_binop (PLUS_EXPR
, vr1max
, integer_one_node
);
7118 else if (*vr0type
== VR_RANGE
7119 && vr1type
== VR_ANTI_RANGE
)
7121 if (TREE_CODE (*vr0min
) == INTEGER_CST
)
7125 *vr0max
= int_const_binop (MINUS_EXPR
, *vr0min
, integer_one_node
);
7139 *vr0type
= VR_VARYING
;
7140 *vr0min
= NULL_TREE
;
7141 *vr0max
= NULL_TREE
;
7144 /* Intersect the two value-ranges { *VR0TYPE, *VR0MIN, *VR0MAX } and
7145 { VR1TYPE, VR0MIN, VR0MAX } and store the result
7146 in { *VR0TYPE, *VR0MIN, *VR0MAX }. This may not be the smallest
7147 possible such range. The resulting range is not canonicalized. */
7150 intersect_ranges (enum value_range_type
*vr0type
,
7151 tree
*vr0min
, tree
*vr0max
,
7152 enum value_range_type vr1type
,
7153 tree vr1min
, tree vr1max
)
7155 bool mineq
= operand_equal_p (*vr0min
, vr1min
, 0);
7156 bool maxeq
= operand_equal_p (*vr0max
, vr1max
, 0);
7158 /* [] is vr0, () is vr1 in the following classification comments. */
7162 if (*vr0type
== vr1type
)
7163 /* Nothing to do for equal ranges. */
7165 else if ((*vr0type
== VR_RANGE
7166 && vr1type
== VR_ANTI_RANGE
)
7167 || (*vr0type
== VR_ANTI_RANGE
7168 && vr1type
== VR_RANGE
))
7170 /* For anti-range with range intersection the result is empty. */
7171 *vr0type
= VR_UNDEFINED
;
7172 *vr0min
= NULL_TREE
;
7173 *vr0max
= NULL_TREE
;
7178 else if (operand_less_p (*vr0max
, vr1min
) == 1
7179 || operand_less_p (vr1max
, *vr0min
) == 1)
7181 /* [ ] ( ) or ( ) [ ]
7182 If the ranges have an empty intersection, the result of the
7183 intersect operation is the range for intersecting an
7184 anti-range with a range or empty when intersecting two ranges. */
7185 if (*vr0type
== VR_RANGE
7186 && vr1type
== VR_ANTI_RANGE
)
7188 else if (*vr0type
== VR_ANTI_RANGE
7189 && vr1type
== VR_RANGE
)
7195 else if (*vr0type
== VR_RANGE
7196 && vr1type
== VR_RANGE
)
7198 *vr0type
= VR_UNDEFINED
;
7199 *vr0min
= NULL_TREE
;
7200 *vr0max
= NULL_TREE
;
7202 else if (*vr0type
== VR_ANTI_RANGE
7203 && vr1type
== VR_ANTI_RANGE
)
7205 /* If the anti-ranges are adjacent to each other merge them. */
7206 if (TREE_CODE (*vr0max
) == INTEGER_CST
7207 && TREE_CODE (vr1min
) == INTEGER_CST
7208 && operand_less_p (*vr0max
, vr1min
) == 1
7209 && integer_onep (int_const_binop (MINUS_EXPR
,
7212 else if (TREE_CODE (vr1max
) == INTEGER_CST
7213 && TREE_CODE (*vr0min
) == INTEGER_CST
7214 && operand_less_p (vr1max
, *vr0min
) == 1
7215 && integer_onep (int_const_binop (MINUS_EXPR
,
7218 /* Else arbitrarily take VR0. */
7221 else if ((maxeq
|| operand_less_p (vr1max
, *vr0max
) == 1)
7222 && (mineq
|| operand_less_p (*vr0min
, vr1min
) == 1))
7224 /* [ ( ) ] or [( ) ] or [ ( )] */
7225 if (*vr0type
== VR_RANGE
7226 && vr1type
== VR_RANGE
)
7228 /* If both are ranges the result is the inner one. */
7233 else if (*vr0type
== VR_RANGE
7234 && vr1type
== VR_ANTI_RANGE
)
7236 /* Choose the right gap if the left one is empty. */
7239 if (TREE_CODE (vr1max
) == INTEGER_CST
)
7240 *vr0min
= int_const_binop (PLUS_EXPR
, vr1max
, integer_one_node
);
7244 /* Choose the left gap if the right one is empty. */
7247 if (TREE_CODE (vr1min
) == INTEGER_CST
)
7248 *vr0max
= int_const_binop (MINUS_EXPR
, vr1min
,
7253 /* Choose the anti-range if the range is effectively varying. */
7254 else if (vrp_val_is_min (*vr0min
)
7255 && vrp_val_is_max (*vr0max
))
7261 /* Else choose the range. */
7263 else if (*vr0type
== VR_ANTI_RANGE
7264 && vr1type
== VR_ANTI_RANGE
)
7265 /* If both are anti-ranges the result is the outer one. */
7267 else if (*vr0type
== VR_ANTI_RANGE
7268 && vr1type
== VR_RANGE
)
7270 /* The intersection is empty. */
7271 *vr0type
= VR_UNDEFINED
;
7272 *vr0min
= NULL_TREE
;
7273 *vr0max
= NULL_TREE
;
7278 else if ((maxeq
|| operand_less_p (*vr0max
, vr1max
) == 1)
7279 && (mineq
|| operand_less_p (vr1min
, *vr0min
) == 1))
7281 /* ( [ ] ) or ([ ] ) or ( [ ]) */
7282 if (*vr0type
== VR_RANGE
7283 && vr1type
== VR_RANGE
)
7284 /* Choose the inner range. */
7286 else if (*vr0type
== VR_ANTI_RANGE
7287 && vr1type
== VR_RANGE
)
7289 /* Choose the right gap if the left is empty. */
7292 *vr0type
= VR_RANGE
;
7293 if (TREE_CODE (*vr0max
) == INTEGER_CST
)
7294 *vr0min
= int_const_binop (PLUS_EXPR
, *vr0max
,
7300 /* Choose the left gap if the right is empty. */
7303 *vr0type
= VR_RANGE
;
7304 if (TREE_CODE (*vr0min
) == INTEGER_CST
)
7305 *vr0max
= int_const_binop (MINUS_EXPR
, *vr0min
,
7311 /* Choose the anti-range if the range is effectively varying. */
7312 else if (vrp_val_is_min (vr1min
)
7313 && vrp_val_is_max (vr1max
))
7315 /* Else choose the range. */
7323 else if (*vr0type
== VR_ANTI_RANGE
7324 && vr1type
== VR_ANTI_RANGE
)
7326 /* If both are anti-ranges the result is the outer one. */
7331 else if (vr1type
== VR_ANTI_RANGE
7332 && *vr0type
== VR_RANGE
)
7334 /* The intersection is empty. */
7335 *vr0type
= VR_UNDEFINED
;
7336 *vr0min
= NULL_TREE
;
7337 *vr0max
= NULL_TREE
;
7342 else if ((operand_less_p (vr1min
, *vr0max
) == 1
7343 || operand_equal_p (vr1min
, *vr0max
, 0))
7344 && operand_less_p (*vr0min
, vr1min
) == 1)
7346 /* [ ( ] ) or [ ]( ) */
7347 if (*vr0type
== VR_ANTI_RANGE
7348 && vr1type
== VR_ANTI_RANGE
)
7350 else if (*vr0type
== VR_RANGE
7351 && vr1type
== VR_RANGE
)
7353 else if (*vr0type
== VR_RANGE
7354 && vr1type
== VR_ANTI_RANGE
)
7356 if (TREE_CODE (vr1min
) == INTEGER_CST
)
7357 *vr0max
= int_const_binop (MINUS_EXPR
, vr1min
,
7362 else if (*vr0type
== VR_ANTI_RANGE
7363 && vr1type
== VR_RANGE
)
7365 *vr0type
= VR_RANGE
;
7366 if (TREE_CODE (*vr0max
) == INTEGER_CST
)
7367 *vr0min
= int_const_binop (PLUS_EXPR
, *vr0max
,
7376 else if ((operand_less_p (*vr0min
, vr1max
) == 1
7377 || operand_equal_p (*vr0min
, vr1max
, 0))
7378 && operand_less_p (vr1min
, *vr0min
) == 1)
7380 /* ( [ ) ] or ( )[ ] */
7381 if (*vr0type
== VR_ANTI_RANGE
7382 && vr1type
== VR_ANTI_RANGE
)
7384 else if (*vr0type
== VR_RANGE
7385 && vr1type
== VR_RANGE
)
7387 else if (*vr0type
== VR_RANGE
7388 && vr1type
== VR_ANTI_RANGE
)
7390 if (TREE_CODE (vr1max
) == INTEGER_CST
)
7391 *vr0min
= int_const_binop (PLUS_EXPR
, vr1max
,
7396 else if (*vr0type
== VR_ANTI_RANGE
7397 && vr1type
== VR_RANGE
)
7399 *vr0type
= VR_RANGE
;
7400 if (TREE_CODE (*vr0min
) == INTEGER_CST
)
7401 *vr0max
= int_const_binop (MINUS_EXPR
, *vr0min
,
7411 /* As a fallback simply use { *VRTYPE, *VR0MIN, *VR0MAX } as
7412 result for the intersection. That's always a conservative
7413 correct estimate. */
7419 /* Intersect the two value-ranges *VR0 and *VR1 and store the result
7420 in *VR0. This may not be the smallest possible such range. */
7423 vrp_intersect_ranges_1 (value_range_t
*vr0
, value_range_t
*vr1
)
7425 value_range_t saved
;
7427 /* If either range is VR_VARYING the other one wins. */
7428 if (vr1
->type
== VR_VARYING
)
7430 if (vr0
->type
== VR_VARYING
)
7432 copy_value_range (vr0
, vr1
);
7436 /* When either range is VR_UNDEFINED the resulting range is
7437 VR_UNDEFINED, too. */
7438 if (vr0
->type
== VR_UNDEFINED
)
7440 if (vr1
->type
== VR_UNDEFINED
)
7442 set_value_range_to_undefined (vr0
);
7446 /* Save the original vr0 so we can return it as conservative intersection
7447 result when our worker turns things to varying. */
7449 intersect_ranges (&vr0
->type
, &vr0
->min
, &vr0
->max
,
7450 vr1
->type
, vr1
->min
, vr1
->max
);
7451 /* Make sure to canonicalize the result though as the inversion of a
7452 VR_RANGE can still be a VR_RANGE. */
7453 set_and_canonicalize_value_range (vr0
, vr0
->type
,
7454 vr0
->min
, vr0
->max
, vr0
->equiv
);
7455 /* If that failed, use the saved original VR0. */
7456 if (vr0
->type
== VR_VARYING
)
7461 /* If the result is VR_UNDEFINED there is no need to mess with
7462 the equivalencies. */
7463 if (vr0
->type
== VR_UNDEFINED
)
7466 /* The resulting set of equivalences for range intersection is the union of
7468 if (vr0
->equiv
&& vr1
->equiv
&& vr0
->equiv
!= vr1
->equiv
)
7469 bitmap_ior_into (vr0
->equiv
, vr1
->equiv
);
7470 else if (vr1
->equiv
&& !vr0
->equiv
)
7471 bitmap_copy (vr0
->equiv
, vr1
->equiv
);
7475 vrp_intersect_ranges (value_range_t
*vr0
, value_range_t
*vr1
)
7477 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
7479 fprintf (dump_file
, "Intersecting\n ");
7480 dump_value_range (dump_file
, vr0
);
7481 fprintf (dump_file
, "\nand\n ");
7482 dump_value_range (dump_file
, vr1
);
7483 fprintf (dump_file
, "\n");
7485 vrp_intersect_ranges_1 (vr0
, vr1
);
7486 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
7488 fprintf (dump_file
, "to\n ");
7489 dump_value_range (dump_file
, vr0
);
7490 fprintf (dump_file
, "\n");
7494 /* Meet operation for value ranges. Given two value ranges VR0 and
7495 VR1, store in VR0 a range that contains both VR0 and VR1. This
7496 may not be the smallest possible such range. */
7499 vrp_meet_1 (value_range_t
*vr0
, value_range_t
*vr1
)
7501 value_range_t saved
;
7503 if (vr0
->type
== VR_UNDEFINED
)
7505 /* Drop equivalences. See PR53465. */
7506 set_value_range (vr0
, vr1
->type
, vr1
->min
, vr1
->max
, NULL
);
7510 if (vr1
->type
== VR_UNDEFINED
)
7512 /* VR0 already has the resulting range, just drop equivalences.
7515 bitmap_clear (vr0
->equiv
);
7519 if (vr0
->type
== VR_VARYING
)
7521 /* Nothing to do. VR0 already has the resulting range. */
7525 if (vr1
->type
== VR_VARYING
)
7527 set_value_range_to_varying (vr0
);
7532 union_ranges (&vr0
->type
, &vr0
->min
, &vr0
->max
,
7533 vr1
->type
, vr1
->min
, vr1
->max
);
7534 if (vr0
->type
== VR_VARYING
)
7536 /* Failed to find an efficient meet. Before giving up and setting
7537 the result to VARYING, see if we can at least derive a useful
7538 anti-range. FIXME, all this nonsense about distinguishing
7539 anti-ranges from ranges is necessary because of the odd
7540 semantics of range_includes_zero_p and friends. */
7541 if (((saved
.type
== VR_RANGE
7542 && range_includes_zero_p (saved
.min
, saved
.max
) == 0)
7543 || (saved
.type
== VR_ANTI_RANGE
7544 && range_includes_zero_p (saved
.min
, saved
.max
) == 1))
7545 && ((vr1
->type
== VR_RANGE
7546 && range_includes_zero_p (vr1
->min
, vr1
->max
) == 0)
7547 || (vr1
->type
== VR_ANTI_RANGE
7548 && range_includes_zero_p (vr1
->min
, vr1
->max
) == 1)))
7550 set_value_range_to_nonnull (vr0
, TREE_TYPE (saved
.min
));
7552 /* Since this meet operation did not result from the meeting of
7553 two equivalent names, VR0 cannot have any equivalences. */
7555 bitmap_clear (vr0
->equiv
);
7559 set_value_range_to_varying (vr0
);
7562 set_and_canonicalize_value_range (vr0
, vr0
->type
, vr0
->min
, vr0
->max
,
7564 if (vr0
->type
== VR_VARYING
)
7567 /* The resulting set of equivalences is always the intersection of
7569 if (vr0
->equiv
&& vr1
->equiv
&& vr0
->equiv
!= vr1
->equiv
)
7570 bitmap_and_into (vr0
->equiv
, vr1
->equiv
);
7571 else if (vr0
->equiv
&& !vr1
->equiv
)
7572 bitmap_clear (vr0
->equiv
);
7576 vrp_meet (value_range_t
*vr0
, value_range_t
*vr1
)
7578 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
7580 fprintf (dump_file
, "Meeting\n ");
7581 dump_value_range (dump_file
, vr0
);
7582 fprintf (dump_file
, "\nand\n ");
7583 dump_value_range (dump_file
, vr1
);
7584 fprintf (dump_file
, "\n");
7586 vrp_meet_1 (vr0
, vr1
);
7587 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
7589 fprintf (dump_file
, "to\n ");
7590 dump_value_range (dump_file
, vr0
);
7591 fprintf (dump_file
, "\n");
7596 /* Visit all arguments for PHI node PHI that flow through executable
7597 edges. If a valid value range can be derived from all the incoming
7598 value ranges, set a new range for the LHS of PHI. */
7600 static enum ssa_prop_result
7601 vrp_visit_phi_node (gimple phi
)
7604 tree lhs
= PHI_RESULT (phi
);
7605 value_range_t
*lhs_vr
= get_value_range (lhs
);
7606 value_range_t vr_result
= VR_INITIALIZER
;
7608 int edges
, old_edges
;
7611 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
7613 fprintf (dump_file
, "\nVisiting PHI node: ");
7614 print_gimple_stmt (dump_file
, phi
, 0, dump_flags
);
7618 for (i
= 0; i
< gimple_phi_num_args (phi
); i
++)
7620 edge e
= gimple_phi_arg_edge (phi
, i
);
7622 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
7625 "\n Argument #%d (%d -> %d %sexecutable)\n",
7626 (int) i
, e
->src
->index
, e
->dest
->index
,
7627 (e
->flags
& EDGE_EXECUTABLE
) ? "" : "not ");
7630 if (e
->flags
& EDGE_EXECUTABLE
)
7632 tree arg
= PHI_ARG_DEF (phi
, i
);
7633 value_range_t vr_arg
;
7637 if (TREE_CODE (arg
) == SSA_NAME
)
7639 vr_arg
= *(get_value_range (arg
));
7643 if (is_overflow_infinity (arg
))
7645 arg
= copy_node (arg
);
7646 TREE_OVERFLOW (arg
) = 0;
7649 vr_arg
.type
= VR_RANGE
;
7652 vr_arg
.equiv
= NULL
;
7655 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
7657 fprintf (dump_file
, "\t");
7658 print_generic_expr (dump_file
, arg
, dump_flags
);
7659 fprintf (dump_file
, "\n\tValue: ");
7660 dump_value_range (dump_file
, &vr_arg
);
7661 fprintf (dump_file
, "\n");
7665 copy_value_range (&vr_result
, &vr_arg
);
7667 vrp_meet (&vr_result
, &vr_arg
);
7670 if (vr_result
.type
== VR_VARYING
)
7675 if (vr_result
.type
== VR_VARYING
)
7677 else if (vr_result
.type
== VR_UNDEFINED
)
7680 old_edges
= vr_phi_edge_counts
[SSA_NAME_VERSION (lhs
)];
7681 vr_phi_edge_counts
[SSA_NAME_VERSION (lhs
)] = edges
;
7683 /* To prevent infinite iterations in the algorithm, derive ranges
7684 when the new value is slightly bigger or smaller than the
7685 previous one. We don't do this if we have seen a new executable
7686 edge; this helps us avoid an overflow infinity for conditionals
7687 which are not in a loop. */
7689 && gimple_phi_num_args (phi
) > 1
7690 && edges
== old_edges
)
7692 int cmp_min
= compare_values (lhs_vr
->min
, vr_result
.min
);
7693 int cmp_max
= compare_values (lhs_vr
->max
, vr_result
.max
);
7695 /* For non VR_RANGE or for pointers fall back to varying if
7696 the range changed. */
7697 if ((lhs_vr
->type
!= VR_RANGE
|| vr_result
.type
!= VR_RANGE
7698 || POINTER_TYPE_P (TREE_TYPE (lhs
)))
7699 && (cmp_min
!= 0 || cmp_max
!= 0))
7702 /* If the new minimum is smaller or larger than the previous
7703 one, go all the way to -INF. In the first case, to avoid
7704 iterating millions of times to reach -INF, and in the
7705 other case to avoid infinite bouncing between different
7707 if (cmp_min
> 0 || cmp_min
< 0)
7709 if (!needs_overflow_infinity (TREE_TYPE (vr_result
.min
))
7710 || !vrp_var_may_overflow (lhs
, phi
))
7711 vr_result
.min
= TYPE_MIN_VALUE (TREE_TYPE (vr_result
.min
));
7712 else if (supports_overflow_infinity (TREE_TYPE (vr_result
.min
)))
7714 negative_overflow_infinity (TREE_TYPE (vr_result
.min
));
7717 /* Similarly, if the new maximum is smaller or larger than
7718 the previous one, go all the way to +INF. */
7719 if (cmp_max
< 0 || cmp_max
> 0)
7721 if (!needs_overflow_infinity (TREE_TYPE (vr_result
.max
))
7722 || !vrp_var_may_overflow (lhs
, phi
))
7723 vr_result
.max
= TYPE_MAX_VALUE (TREE_TYPE (vr_result
.max
));
7724 else if (supports_overflow_infinity (TREE_TYPE (vr_result
.max
)))
7726 positive_overflow_infinity (TREE_TYPE (vr_result
.max
));
7729 /* If we dropped either bound to +-INF then if this is a loop
7730 PHI node SCEV may known more about its value-range. */
7731 if ((cmp_min
> 0 || cmp_min
< 0
7732 || cmp_max
< 0 || cmp_max
> 0)
7734 && (l
= loop_containing_stmt (phi
))
7735 && l
->header
== gimple_bb (phi
))
7736 adjust_range_with_scev (&vr_result
, l
, phi
, lhs
);
7738 /* If we will end up with a (-INF, +INF) range, set it to
7739 VARYING. Same if the previous max value was invalid for
7740 the type and we end up with vr_result.min > vr_result.max. */
7741 if ((vrp_val_is_max (vr_result
.max
)
7742 && vrp_val_is_min (vr_result
.min
))
7743 || compare_values (vr_result
.min
,
7748 /* If the new range is different than the previous value, keep
7751 if (update_value_range (lhs
, &vr_result
))
7753 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
7755 fprintf (dump_file
, "Found new range for ");
7756 print_generic_expr (dump_file
, lhs
, 0);
7757 fprintf (dump_file
, ": ");
7758 dump_value_range (dump_file
, &vr_result
);
7759 fprintf (dump_file
, "\n\n");
7762 return SSA_PROP_INTERESTING
;
7765 /* Nothing changed, don't add outgoing edges. */
7766 return SSA_PROP_NOT_INTERESTING
;
7768 /* No match found. Set the LHS to VARYING. */
7770 set_value_range_to_varying (lhs_vr
);
7771 return SSA_PROP_VARYING
;
7774 /* Simplify boolean operations if the source is known
7775 to be already a boolean. */
7777 simplify_truth_ops_using_ranges (gimple_stmt_iterator
*gsi
, gimple stmt
)
7779 enum tree_code rhs_code
= gimple_assign_rhs_code (stmt
);
7781 bool need_conversion
;
7783 /* We handle only !=/== case here. */
7784 gcc_assert (rhs_code
== EQ_EXPR
|| rhs_code
== NE_EXPR
);
7786 op0
= gimple_assign_rhs1 (stmt
);
7787 if (!op_with_boolean_value_range_p (op0
))
7790 op1
= gimple_assign_rhs2 (stmt
);
7791 if (!op_with_boolean_value_range_p (op1
))
7794 /* Reduce number of cases to handle to NE_EXPR. As there is no
7795 BIT_XNOR_EXPR we cannot replace A == B with a single statement. */
7796 if (rhs_code
== EQ_EXPR
)
7798 if (TREE_CODE (op1
) == INTEGER_CST
)
7799 op1
= int_const_binop (BIT_XOR_EXPR
, op1
, integer_one_node
);
7804 lhs
= gimple_assign_lhs (stmt
);
7806 = !useless_type_conversion_p (TREE_TYPE (lhs
), TREE_TYPE (op0
));
7808 /* Make sure to not sign-extend a 1-bit 1 when converting the result. */
7810 && !TYPE_UNSIGNED (TREE_TYPE (op0
))
7811 && TYPE_PRECISION (TREE_TYPE (op0
)) == 1
7812 && TYPE_PRECISION (TREE_TYPE (lhs
)) > 1)
7815 /* For A != 0 we can substitute A itself. */
7816 if (integer_zerop (op1
))
7817 gimple_assign_set_rhs_with_ops (gsi
,
7819 ? NOP_EXPR
: TREE_CODE (op0
),
7821 /* For A != B we substitute A ^ B. Either with conversion. */
7822 else if (need_conversion
)
7825 tree tem
= create_tmp_reg (TREE_TYPE (op0
), NULL
);
7826 newop
= gimple_build_assign_with_ops (BIT_XOR_EXPR
, tem
, op0
, op1
);
7827 tem
= make_ssa_name (tem
, newop
);
7828 gimple_assign_set_lhs (newop
, tem
);
7829 gsi_insert_before (gsi
, newop
, GSI_SAME_STMT
);
7830 update_stmt (newop
);
7831 gimple_assign_set_rhs_with_ops (gsi
, NOP_EXPR
, tem
, NULL_TREE
);
7835 gimple_assign_set_rhs_with_ops (gsi
, BIT_XOR_EXPR
, op0
, op1
);
7836 update_stmt (gsi_stmt (*gsi
));
7841 /* Simplify a division or modulo operator to a right shift or
7842 bitwise and if the first operand is unsigned or is greater
7843 than zero and the second operand is an exact power of two. */
7846 simplify_div_or_mod_using_ranges (gimple stmt
)
7848 enum tree_code rhs_code
= gimple_assign_rhs_code (stmt
);
7850 tree op0
= gimple_assign_rhs1 (stmt
);
7851 tree op1
= gimple_assign_rhs2 (stmt
);
7852 value_range_t
*vr
= get_value_range (gimple_assign_rhs1 (stmt
));
7854 if (TYPE_UNSIGNED (TREE_TYPE (op0
)))
7856 val
= integer_one_node
;
7862 val
= compare_range_with_value (GE_EXPR
, vr
, integer_zero_node
, &sop
);
7866 && integer_onep (val
)
7867 && issue_strict_overflow_warning (WARN_STRICT_OVERFLOW_MISC
))
7869 location_t location
;
7871 if (!gimple_has_location (stmt
))
7872 location
= input_location
;
7874 location
= gimple_location (stmt
);
7875 warning_at (location
, OPT_Wstrict_overflow
,
7876 "assuming signed overflow does not occur when "
7877 "simplifying %</%> or %<%%%> to %<>>%> or %<&%>");
7881 if (val
&& integer_onep (val
))
7885 if (rhs_code
== TRUNC_DIV_EXPR
)
7887 t
= build_int_cst (integer_type_node
, tree_log2 (op1
));
7888 gimple_assign_set_rhs_code (stmt
, RSHIFT_EXPR
);
7889 gimple_assign_set_rhs1 (stmt
, op0
);
7890 gimple_assign_set_rhs2 (stmt
, t
);
7894 t
= build_int_cst (TREE_TYPE (op1
), 1);
7895 t
= int_const_binop (MINUS_EXPR
, op1
, t
);
7896 t
= fold_convert (TREE_TYPE (op0
), t
);
7898 gimple_assign_set_rhs_code (stmt
, BIT_AND_EXPR
);
7899 gimple_assign_set_rhs1 (stmt
, op0
);
7900 gimple_assign_set_rhs2 (stmt
, t
);
7910 /* If the operand to an ABS_EXPR is >= 0, then eliminate the
7911 ABS_EXPR. If the operand is <= 0, then simplify the
7912 ABS_EXPR into a NEGATE_EXPR. */
7915 simplify_abs_using_ranges (gimple stmt
)
7918 tree op
= gimple_assign_rhs1 (stmt
);
7919 tree type
= TREE_TYPE (op
);
7920 value_range_t
*vr
= get_value_range (op
);
7922 if (TYPE_UNSIGNED (type
))
7924 val
= integer_zero_node
;
7930 val
= compare_range_with_value (LE_EXPR
, vr
, integer_zero_node
, &sop
);
7934 val
= compare_range_with_value (GE_EXPR
, vr
, integer_zero_node
,
7939 if (integer_zerop (val
))
7940 val
= integer_one_node
;
7941 else if (integer_onep (val
))
7942 val
= integer_zero_node
;
7947 && (integer_onep (val
) || integer_zerop (val
)))
7949 if (sop
&& issue_strict_overflow_warning (WARN_STRICT_OVERFLOW_MISC
))
7951 location_t location
;
7953 if (!gimple_has_location (stmt
))
7954 location
= input_location
;
7956 location
= gimple_location (stmt
);
7957 warning_at (location
, OPT_Wstrict_overflow
,
7958 "assuming signed overflow does not occur when "
7959 "simplifying %<abs (X)%> to %<X%> or %<-X%>");
7962 gimple_assign_set_rhs1 (stmt
, op
);
7963 if (integer_onep (val
))
7964 gimple_assign_set_rhs_code (stmt
, NEGATE_EXPR
);
7966 gimple_assign_set_rhs_code (stmt
, SSA_NAME
);
7975 /* Optimize away redundant BIT_AND_EXPR and BIT_IOR_EXPR.
7976 If all the bits that are being cleared by & are already
7977 known to be zero from VR, or all the bits that are being
7978 set by | are already known to be one from VR, the bit
7979 operation is redundant. */
7982 simplify_bit_ops_using_ranges (gimple_stmt_iterator
*gsi
, gimple stmt
)
7984 tree op0
= gimple_assign_rhs1 (stmt
);
7985 tree op1
= gimple_assign_rhs2 (stmt
);
7986 tree op
= NULL_TREE
;
7987 value_range_t vr0
= VR_INITIALIZER
;
7988 value_range_t vr1
= VR_INITIALIZER
;
7989 double_int may_be_nonzero0
, may_be_nonzero1
;
7990 double_int must_be_nonzero0
, must_be_nonzero1
;
7993 if (TREE_CODE (op0
) == SSA_NAME
)
7994 vr0
= *(get_value_range (op0
));
7995 else if (is_gimple_min_invariant (op0
))
7996 set_value_range_to_value (&vr0
, op0
, NULL
);
8000 if (TREE_CODE (op1
) == SSA_NAME
)
8001 vr1
= *(get_value_range (op1
));
8002 else if (is_gimple_min_invariant (op1
))
8003 set_value_range_to_value (&vr1
, op1
, NULL
);
8007 if (!zero_nonzero_bits_from_vr (&vr0
, &may_be_nonzero0
, &must_be_nonzero0
))
8009 if (!zero_nonzero_bits_from_vr (&vr1
, &may_be_nonzero1
, &must_be_nonzero1
))
8012 switch (gimple_assign_rhs_code (stmt
))
8015 mask
= double_int_and_not (may_be_nonzero0
, must_be_nonzero1
);
8016 if (double_int_zero_p (mask
))
8021 mask
= double_int_and_not (may_be_nonzero1
, must_be_nonzero0
);
8022 if (double_int_zero_p (mask
))
8029 mask
= double_int_and_not (may_be_nonzero0
, must_be_nonzero1
);
8030 if (double_int_zero_p (mask
))
8035 mask
= double_int_and_not (may_be_nonzero1
, must_be_nonzero0
);
8036 if (double_int_zero_p (mask
))
8046 if (op
== NULL_TREE
)
8049 gimple_assign_set_rhs_with_ops (gsi
, TREE_CODE (op
), op
, NULL
);
8050 update_stmt (gsi_stmt (*gsi
));
8054 /* We are comparing trees OP0 and OP1 using COND_CODE. OP0 has
8055 a known value range VR.
8057 If there is one and only one value which will satisfy the
8058 conditional, then return that value. Else return NULL. */
8061 test_for_singularity (enum tree_code cond_code
, tree op0
,
8062 tree op1
, value_range_t
*vr
)
8067 /* Extract minimum/maximum values which satisfy the
8068 the conditional as it was written. */
8069 if (cond_code
== LE_EXPR
|| cond_code
== LT_EXPR
)
8071 /* This should not be negative infinity; there is no overflow
8073 min
= TYPE_MIN_VALUE (TREE_TYPE (op0
));
8076 if (cond_code
== LT_EXPR
&& !is_overflow_infinity (max
))
8078 tree one
= build_int_cst (TREE_TYPE (op0
), 1);
8079 max
= fold_build2 (MINUS_EXPR
, TREE_TYPE (op0
), max
, one
);
8081 TREE_NO_WARNING (max
) = 1;
8084 else if (cond_code
== GE_EXPR
|| cond_code
== GT_EXPR
)
8086 /* This should not be positive infinity; there is no overflow
8088 max
= TYPE_MAX_VALUE (TREE_TYPE (op0
));
8091 if (cond_code
== GT_EXPR
&& !is_overflow_infinity (min
))
8093 tree one
= build_int_cst (TREE_TYPE (op0
), 1);
8094 min
= fold_build2 (PLUS_EXPR
, TREE_TYPE (op0
), min
, one
);
8096 TREE_NO_WARNING (min
) = 1;
8100 /* Now refine the minimum and maximum values using any
8101 value range information we have for op0. */
8104 if (compare_values (vr
->min
, min
) == 1)
8106 if (compare_values (vr
->max
, max
) == -1)
8109 /* If the new min/max values have converged to a single value,
8110 then there is only one value which can satisfy the condition,
8111 return that value. */
8112 if (operand_equal_p (min
, max
, 0) && is_gimple_min_invariant (min
))
8118 /* Simplify a conditional using a relational operator to an equality
8119 test if the range information indicates only one value can satisfy
8120 the original conditional. */
8123 simplify_cond_using_ranges (gimple stmt
)
8125 tree op0
= gimple_cond_lhs (stmt
);
8126 tree op1
= gimple_cond_rhs (stmt
);
8127 enum tree_code cond_code
= gimple_cond_code (stmt
);
8129 if (cond_code
!= NE_EXPR
8130 && cond_code
!= EQ_EXPR
8131 && TREE_CODE (op0
) == SSA_NAME
8132 && INTEGRAL_TYPE_P (TREE_TYPE (op0
))
8133 && is_gimple_min_invariant (op1
))
8135 value_range_t
*vr
= get_value_range (op0
);
8137 /* If we have range information for OP0, then we might be
8138 able to simplify this conditional. */
8139 if (vr
->type
== VR_RANGE
)
8141 tree new_tree
= test_for_singularity (cond_code
, op0
, op1
, vr
);
8147 fprintf (dump_file
, "Simplified relational ");
8148 print_gimple_stmt (dump_file
, stmt
, 0, 0);
8149 fprintf (dump_file
, " into ");
8152 gimple_cond_set_code (stmt
, EQ_EXPR
);
8153 gimple_cond_set_lhs (stmt
, op0
);
8154 gimple_cond_set_rhs (stmt
, new_tree
);
8160 print_gimple_stmt (dump_file
, stmt
, 0, 0);
8161 fprintf (dump_file
, "\n");
8167 /* Try again after inverting the condition. We only deal
8168 with integral types here, so no need to worry about
8169 issues with inverting FP comparisons. */
8170 cond_code
= invert_tree_comparison (cond_code
, false);
8171 new_tree
= test_for_singularity (cond_code
, op0
, op1
, vr
);
8177 fprintf (dump_file
, "Simplified relational ");
8178 print_gimple_stmt (dump_file
, stmt
, 0, 0);
8179 fprintf (dump_file
, " into ");
8182 gimple_cond_set_code (stmt
, NE_EXPR
);
8183 gimple_cond_set_lhs (stmt
, op0
);
8184 gimple_cond_set_rhs (stmt
, new_tree
);
8190 print_gimple_stmt (dump_file
, stmt
, 0, 0);
8191 fprintf (dump_file
, "\n");
8202 /* Simplify a switch statement using the value range of the switch
8206 simplify_switch_using_ranges (gimple stmt
)
8208 tree op
= gimple_switch_index (stmt
);
8213 size_t i
= 0, j
= 0, n
, n2
;
8217 if (TREE_CODE (op
) == SSA_NAME
)
8219 vr
= get_value_range (op
);
8221 /* We can only handle integer ranges. */
8222 if (vr
->type
!= VR_RANGE
8223 || symbolic_range_p (vr
))
8226 /* Find case label for min/max of the value range. */
8227 take_default
= !find_case_label_range (stmt
, vr
->min
, vr
->max
, &i
, &j
);
8229 else if (TREE_CODE (op
) == INTEGER_CST
)
8231 take_default
= !find_case_label_index (stmt
, 1, op
, &i
);
8245 n
= gimple_switch_num_labels (stmt
);
8247 /* Bail out if this is just all edges taken. */
8253 /* Build a new vector of taken case labels. */
8254 vec2
= make_tree_vec (j
- i
+ 1 + (int)take_default
);
8257 /* Add the default edge, if necessary. */
8259 TREE_VEC_ELT (vec2
, n2
++) = gimple_switch_default_label (stmt
);
8261 for (; i
<= j
; ++i
, ++n2
)
8262 TREE_VEC_ELT (vec2
, n2
) = gimple_switch_label (stmt
, i
);
8264 /* Mark needed edges. */
8265 for (i
= 0; i
< n2
; ++i
)
8267 e
= find_edge (gimple_bb (stmt
),
8268 label_to_block (CASE_LABEL (TREE_VEC_ELT (vec2
, i
))));
8269 e
->aux
= (void *)-1;
8272 /* Queue not needed edges for later removal. */
8273 FOR_EACH_EDGE (e
, ei
, gimple_bb (stmt
)->succs
)
8275 if (e
->aux
== (void *)-1)
8281 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
8283 fprintf (dump_file
, "removing unreachable case label\n");
8285 VEC_safe_push (edge
, heap
, to_remove_edges
, e
);
8286 e
->flags
&= ~EDGE_EXECUTABLE
;
8289 /* And queue an update for the stmt. */
8292 VEC_safe_push (switch_update
, heap
, to_update_switch_stmts
, &su
);
8296 /* Simplify an integral conversion from an SSA name in STMT. */
8299 simplify_conversion_using_ranges (gimple stmt
)
8301 tree innerop
, middleop
, finaltype
;
8303 value_range_t
*innervr
;
8304 bool inner_unsigned_p
, middle_unsigned_p
, final_unsigned_p
;
8305 unsigned inner_prec
, middle_prec
, final_prec
;
8306 double_int innermin
, innermed
, innermax
, middlemin
, middlemed
, middlemax
;
8308 finaltype
= TREE_TYPE (gimple_assign_lhs (stmt
));
8309 if (!INTEGRAL_TYPE_P (finaltype
))
8311 middleop
= gimple_assign_rhs1 (stmt
);
8312 def_stmt
= SSA_NAME_DEF_STMT (middleop
);
8313 if (!is_gimple_assign (def_stmt
)
8314 || !CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (def_stmt
)))
8316 innerop
= gimple_assign_rhs1 (def_stmt
);
8317 if (TREE_CODE (innerop
) != SSA_NAME
)
8320 /* Get the value-range of the inner operand. */
8321 innervr
= get_value_range (innerop
);
8322 if (innervr
->type
!= VR_RANGE
8323 || TREE_CODE (innervr
->min
) != INTEGER_CST
8324 || TREE_CODE (innervr
->max
) != INTEGER_CST
)
8327 /* Simulate the conversion chain to check if the result is equal if
8328 the middle conversion is removed. */
8329 innermin
= tree_to_double_int (innervr
->min
);
8330 innermax
= tree_to_double_int (innervr
->max
);
8332 inner_prec
= TYPE_PRECISION (TREE_TYPE (innerop
));
8333 middle_prec
= TYPE_PRECISION (TREE_TYPE (middleop
));
8334 final_prec
= TYPE_PRECISION (finaltype
);
8336 /* If the first conversion is not injective, the second must not
8338 if (double_int_cmp (double_int_sub (innermax
, innermin
),
8339 double_int_mask (middle_prec
), true) > 0
8340 && middle_prec
< final_prec
)
8342 /* We also want a medium value so that we can track the effect that
8343 narrowing conversions with sign change have. */
8344 inner_unsigned_p
= TYPE_UNSIGNED (TREE_TYPE (innerop
));
8345 if (inner_unsigned_p
)
8346 innermed
= double_int_rshift (double_int_mask (inner_prec
),
8347 1, inner_prec
, false);
8349 innermed
= double_int_zero
;
8350 if (double_int_cmp (innermin
, innermed
, inner_unsigned_p
) >= 0
8351 || double_int_cmp (innermed
, innermax
, inner_unsigned_p
) >= 0)
8352 innermed
= innermin
;
8354 middle_unsigned_p
= TYPE_UNSIGNED (TREE_TYPE (middleop
));
8355 middlemin
= double_int_ext (innermin
, middle_prec
, middle_unsigned_p
);
8356 middlemed
= double_int_ext (innermed
, middle_prec
, middle_unsigned_p
);
8357 middlemax
= double_int_ext (innermax
, middle_prec
, middle_unsigned_p
);
8359 /* Require that the final conversion applied to both the original
8360 and the intermediate range produces the same result. */
8361 final_unsigned_p
= TYPE_UNSIGNED (finaltype
);
8362 if (!double_int_equal_p (double_int_ext (middlemin
,
8363 final_prec
, final_unsigned_p
),
8364 double_int_ext (innermin
,
8365 final_prec
, final_unsigned_p
))
8366 || !double_int_equal_p (double_int_ext (middlemed
,
8367 final_prec
, final_unsigned_p
),
8368 double_int_ext (innermed
,
8369 final_prec
, final_unsigned_p
))
8370 || !double_int_equal_p (double_int_ext (middlemax
,
8371 final_prec
, final_unsigned_p
),
8372 double_int_ext (innermax
,
8373 final_prec
, final_unsigned_p
)))
8376 gimple_assign_set_rhs1 (stmt
, innerop
);
8381 /* Return whether the value range *VR fits in an integer type specified
8382 by PRECISION and UNSIGNED_P. */
8385 range_fits_type_p (value_range_t
*vr
, unsigned precision
, bool unsigned_p
)
8388 unsigned src_precision
;
8391 /* We can only handle integral and pointer types. */
8392 src_type
= TREE_TYPE (vr
->min
);
8393 if (!INTEGRAL_TYPE_P (src_type
)
8394 && !POINTER_TYPE_P (src_type
))
8397 /* An extension is always fine, so is an identity transform. */
8398 src_precision
= TYPE_PRECISION (TREE_TYPE (vr
->min
));
8399 if (src_precision
< precision
8400 || (src_precision
== precision
8401 && TYPE_UNSIGNED (src_type
) == unsigned_p
))
8404 /* Now we can only handle ranges with constant bounds. */
8405 if (vr
->type
!= VR_RANGE
8406 || TREE_CODE (vr
->min
) != INTEGER_CST
8407 || TREE_CODE (vr
->max
) != INTEGER_CST
)
8410 /* For precision-preserving sign-changes the MSB of the double-int
8412 if (src_precision
== precision
8413 && (TREE_INT_CST_HIGH (vr
->min
) | TREE_INT_CST_HIGH (vr
->max
)) < 0)
8416 /* Then we can perform the conversion on both ends and compare
8417 the result for equality. */
8418 tem
= double_int_ext (tree_to_double_int (vr
->min
), precision
, unsigned_p
);
8419 if (!double_int_equal_p (tree_to_double_int (vr
->min
), tem
))
8421 tem
= double_int_ext (tree_to_double_int (vr
->max
), precision
, unsigned_p
);
8422 if (!double_int_equal_p (tree_to_double_int (vr
->max
), tem
))
8428 /* Simplify a conversion from integral SSA name to float in STMT. */
8431 simplify_float_conversion_using_ranges (gimple_stmt_iterator
*gsi
, gimple stmt
)
8433 tree rhs1
= gimple_assign_rhs1 (stmt
);
8434 value_range_t
*vr
= get_value_range (rhs1
);
8435 enum machine_mode fltmode
= TYPE_MODE (TREE_TYPE (gimple_assign_lhs (stmt
)));
8436 enum machine_mode mode
;
8440 /* We can only handle constant ranges. */
8441 if (vr
->type
!= VR_RANGE
8442 || TREE_CODE (vr
->min
) != INTEGER_CST
8443 || TREE_CODE (vr
->max
) != INTEGER_CST
)
8446 /* First check if we can use a signed type in place of an unsigned. */
8447 if (TYPE_UNSIGNED (TREE_TYPE (rhs1
))
8448 && (can_float_p (fltmode
, TYPE_MODE (TREE_TYPE (rhs1
)), 0)
8449 != CODE_FOR_nothing
)
8450 && range_fits_type_p (vr
, GET_MODE_PRECISION
8451 (TYPE_MODE (TREE_TYPE (rhs1
))), 0))
8452 mode
= TYPE_MODE (TREE_TYPE (rhs1
));
8453 /* If we can do the conversion in the current input mode do nothing. */
8454 else if (can_float_p (fltmode
, TYPE_MODE (TREE_TYPE (rhs1
)),
8455 TYPE_UNSIGNED (TREE_TYPE (rhs1
))))
8457 /* Otherwise search for a mode we can use, starting from the narrowest
8458 integer mode available. */
8461 mode
= GET_CLASS_NARROWEST_MODE (MODE_INT
);
8464 /* If we cannot do a signed conversion to float from mode
8465 or if the value-range does not fit in the signed type
8466 try with a wider mode. */
8467 if (can_float_p (fltmode
, mode
, 0) != CODE_FOR_nothing
8468 && range_fits_type_p (vr
, GET_MODE_PRECISION (mode
), 0))
8471 mode
= GET_MODE_WIDER_MODE (mode
);
8472 /* But do not widen the input. Instead leave that to the
8473 optabs expansion code. */
8474 if (GET_MODE_PRECISION (mode
) > TYPE_PRECISION (TREE_TYPE (rhs1
)))
8477 while (mode
!= VOIDmode
);
8478 if (mode
== VOIDmode
)
8482 /* It works, insert a truncation or sign-change before the
8483 float conversion. */
8484 tem
= create_tmp_var (build_nonstandard_integer_type
8485 (GET_MODE_PRECISION (mode
), 0), NULL
);
8486 conv
= gimple_build_assign_with_ops (NOP_EXPR
, tem
, rhs1
, NULL_TREE
);
8487 tem
= make_ssa_name (tem
, conv
);
8488 gimple_assign_set_lhs (conv
, tem
);
8489 gsi_insert_before (gsi
, conv
, GSI_SAME_STMT
);
8490 gimple_assign_set_rhs1 (stmt
, tem
);
8496 /* Simplify STMT using ranges if possible. */
8499 simplify_stmt_using_ranges (gimple_stmt_iterator
*gsi
)
8501 gimple stmt
= gsi_stmt (*gsi
);
8502 if (is_gimple_assign (stmt
))
8504 enum tree_code rhs_code
= gimple_assign_rhs_code (stmt
);
8505 tree rhs1
= gimple_assign_rhs1 (stmt
);
8511 /* Transform EQ_EXPR, NE_EXPR into BIT_XOR_EXPR or identity
8512 if the RHS is zero or one, and the LHS are known to be boolean
8514 if (INTEGRAL_TYPE_P (TREE_TYPE (rhs1
)))
8515 return simplify_truth_ops_using_ranges (gsi
, stmt
);
8518 /* Transform TRUNC_DIV_EXPR and TRUNC_MOD_EXPR into RSHIFT_EXPR
8519 and BIT_AND_EXPR respectively if the first operand is greater
8520 than zero and the second operand is an exact power of two. */
8521 case TRUNC_DIV_EXPR
:
8522 case TRUNC_MOD_EXPR
:
8523 if (INTEGRAL_TYPE_P (TREE_TYPE (rhs1
))
8524 && integer_pow2p (gimple_assign_rhs2 (stmt
)))
8525 return simplify_div_or_mod_using_ranges (stmt
);
8528 /* Transform ABS (X) into X or -X as appropriate. */
8530 if (TREE_CODE (rhs1
) == SSA_NAME
8531 && INTEGRAL_TYPE_P (TREE_TYPE (rhs1
)))
8532 return simplify_abs_using_ranges (stmt
);
8537 /* Optimize away BIT_AND_EXPR and BIT_IOR_EXPR
8538 if all the bits being cleared are already cleared or
8539 all the bits being set are already set. */
8540 if (INTEGRAL_TYPE_P (TREE_TYPE (rhs1
)))
8541 return simplify_bit_ops_using_ranges (gsi
, stmt
);
8545 if (TREE_CODE (rhs1
) == SSA_NAME
8546 && INTEGRAL_TYPE_P (TREE_TYPE (rhs1
)))
8547 return simplify_conversion_using_ranges (stmt
);
8551 if (TREE_CODE (rhs1
) == SSA_NAME
8552 && INTEGRAL_TYPE_P (TREE_TYPE (rhs1
)))
8553 return simplify_float_conversion_using_ranges (gsi
, stmt
);
8560 else if (gimple_code (stmt
) == GIMPLE_COND
)
8561 return simplify_cond_using_ranges (stmt
);
8562 else if (gimple_code (stmt
) == GIMPLE_SWITCH
)
8563 return simplify_switch_using_ranges (stmt
);
8568 /* If the statement pointed by SI has a predicate whose value can be
8569 computed using the value range information computed by VRP, compute
8570 its value and return true. Otherwise, return false. */
8573 fold_predicate_in (gimple_stmt_iterator
*si
)
8575 bool assignment_p
= false;
8577 gimple stmt
= gsi_stmt (*si
);
8579 if (is_gimple_assign (stmt
)
8580 && TREE_CODE_CLASS (gimple_assign_rhs_code (stmt
)) == tcc_comparison
)
8582 assignment_p
= true;
8583 val
= vrp_evaluate_conditional (gimple_assign_rhs_code (stmt
),
8584 gimple_assign_rhs1 (stmt
),
8585 gimple_assign_rhs2 (stmt
),
8588 else if (gimple_code (stmt
) == GIMPLE_COND
)
8589 val
= vrp_evaluate_conditional (gimple_cond_code (stmt
),
8590 gimple_cond_lhs (stmt
),
8591 gimple_cond_rhs (stmt
),
8599 val
= fold_convert (gimple_expr_type (stmt
), val
);
8603 fprintf (dump_file
, "Folding predicate ");
8604 print_gimple_expr (dump_file
, stmt
, 0, 0);
8605 fprintf (dump_file
, " to ");
8606 print_generic_expr (dump_file
, val
, 0);
8607 fprintf (dump_file
, "\n");
8610 if (is_gimple_assign (stmt
))
8611 gimple_assign_set_rhs_from_tree (si
, val
);
8614 gcc_assert (gimple_code (stmt
) == GIMPLE_COND
);
8615 if (integer_zerop (val
))
8616 gimple_cond_make_false (stmt
);
8617 else if (integer_onep (val
))
8618 gimple_cond_make_true (stmt
);
8629 /* Callback for substitute_and_fold folding the stmt at *SI. */
8632 vrp_fold_stmt (gimple_stmt_iterator
*si
)
8634 if (fold_predicate_in (si
))
8637 return simplify_stmt_using_ranges (si
);
8640 /* Stack of dest,src equivalency pairs that need to be restored after
8641 each attempt to thread a block's incoming edge to an outgoing edge.
8643 A NULL entry is used to mark the end of pairs which need to be
8645 static VEC(tree
,heap
) *stack
;
8647 /* A trivial wrapper so that we can present the generic jump threading
8648 code with a simple API for simplifying statements. STMT is the
8649 statement we want to simplify, WITHIN_STMT provides the location
8650 for any overflow warnings. */
8653 simplify_stmt_for_jump_threading (gimple stmt
, gimple within_stmt
)
8655 /* We only use VRP information to simplify conditionals. This is
8656 overly conservative, but it's unclear if doing more would be
8657 worth the compile time cost. */
8658 if (gimple_code (stmt
) != GIMPLE_COND
)
8661 return vrp_evaluate_conditional (gimple_cond_code (stmt
),
8662 gimple_cond_lhs (stmt
),
8663 gimple_cond_rhs (stmt
), within_stmt
);
8666 /* Blocks which have more than one predecessor and more than
8667 one successor present jump threading opportunities, i.e.,
8668 when the block is reached from a specific predecessor, we
8669 may be able to determine which of the outgoing edges will
8670 be traversed. When this optimization applies, we are able
8671 to avoid conditionals at runtime and we may expose secondary
8672 optimization opportunities.
8674 This routine is effectively a driver for the generic jump
8675 threading code. It basically just presents the generic code
8676 with edges that may be suitable for jump threading.
8678 Unlike DOM, we do not iterate VRP if jump threading was successful.
8679 While iterating may expose new opportunities for VRP, it is expected
8680 those opportunities would be very limited and the compile time cost
8681 to expose those opportunities would be significant.
8683 As jump threading opportunities are discovered, they are registered
8684 for later realization. */
8687 identify_jump_threads (void)
8694 /* Ugh. When substituting values earlier in this pass we can
8695 wipe the dominance information. So rebuild the dominator
8696 information as we need it within the jump threading code. */
8697 calculate_dominance_info (CDI_DOMINATORS
);
8699 /* We do not allow VRP information to be used for jump threading
8700 across a back edge in the CFG. Otherwise it becomes too
8701 difficult to avoid eliminating loop exit tests. Of course
8702 EDGE_DFS_BACK is not accurate at this time so we have to
8704 mark_dfs_back_edges ();
8706 /* Do not thread across edges we are about to remove. Just marking
8707 them as EDGE_DFS_BACK will do. */
8708 FOR_EACH_VEC_ELT (edge
, to_remove_edges
, i
, e
)
8709 e
->flags
|= EDGE_DFS_BACK
;
8711 /* Allocate our unwinder stack to unwind any temporary equivalences
8712 that might be recorded. */
8713 stack
= VEC_alloc (tree
, heap
, 20);
8715 /* To avoid lots of silly node creation, we create a single
8716 conditional and just modify it in-place when attempting to
8718 dummy
= gimple_build_cond (EQ_EXPR
,
8719 integer_zero_node
, integer_zero_node
,
8722 /* Walk through all the blocks finding those which present a
8723 potential jump threading opportunity. We could set this up
8724 as a dominator walker and record data during the walk, but
8725 I doubt it's worth the effort for the classes of jump
8726 threading opportunities we are trying to identify at this
8727 point in compilation. */
8732 /* If the generic jump threading code does not find this block
8733 interesting, then there is nothing to do. */
8734 if (! potentially_threadable_block (bb
))
8737 /* We only care about blocks ending in a COND_EXPR. While there
8738 may be some value in handling SWITCH_EXPR here, I doubt it's
8739 terribly important. */
8740 last
= gsi_stmt (gsi_last_bb (bb
));
8742 /* We're basically looking for a switch or any kind of conditional with
8743 integral or pointer type arguments. Note the type of the second
8744 argument will be the same as the first argument, so no need to
8745 check it explicitly. */
8746 if (gimple_code (last
) == GIMPLE_SWITCH
8747 || (gimple_code (last
) == GIMPLE_COND
8748 && TREE_CODE (gimple_cond_lhs (last
)) == SSA_NAME
8749 && (INTEGRAL_TYPE_P (TREE_TYPE (gimple_cond_lhs (last
)))
8750 || POINTER_TYPE_P (TREE_TYPE (gimple_cond_lhs (last
))))
8751 && (TREE_CODE (gimple_cond_rhs (last
)) == SSA_NAME
8752 || is_gimple_min_invariant (gimple_cond_rhs (last
)))))
8756 /* We've got a block with multiple predecessors and multiple
8757 successors which also ends in a suitable conditional or
8758 switch statement. For each predecessor, see if we can thread
8759 it to a specific successor. */
8760 FOR_EACH_EDGE (e
, ei
, bb
->preds
)
8762 /* Do not thread across back edges or abnormal edges
8764 if (e
->flags
& (EDGE_DFS_BACK
| EDGE_COMPLEX
))
8767 thread_across_edge (dummy
, e
, true, &stack
,
8768 simplify_stmt_for_jump_threading
);
8773 /* We do not actually update the CFG or SSA graphs at this point as
8774 ASSERT_EXPRs are still in the IL and cfg cleanup code does not yet
8775 handle ASSERT_EXPRs gracefully. */
8778 /* We identified all the jump threading opportunities earlier, but could
8779 not transform the CFG at that time. This routine transforms the
8780 CFG and arranges for the dominator tree to be rebuilt if necessary.
8782 Note the SSA graph update will occur during the normal TODO
8783 processing by the pass manager. */
8785 finalize_jump_threads (void)
8787 thread_through_all_blocks (false);
8788 VEC_free (tree
, heap
, stack
);
8792 /* Traverse all the blocks folding conditionals with known ranges. */
8799 values_propagated
= true;
8803 fprintf (dump_file
, "\nValue ranges after VRP:\n\n");
8804 dump_all_value_ranges (dump_file
);
8805 fprintf (dump_file
, "\n");
8808 substitute_and_fold (op_with_constant_singleton_value_range
,
8809 vrp_fold_stmt
, false);
8811 if (warn_array_bounds
)
8812 check_all_array_refs ();
8814 /* We must identify jump threading opportunities before we release
8815 the datastructures built by VRP. */
8816 identify_jump_threads ();
8818 /* Free allocated memory. */
8819 for (i
= 0; i
< num_vr_values
; i
++)
8822 BITMAP_FREE (vr_value
[i
]->equiv
);
8827 free (vr_phi_edge_counts
);
8829 /* So that we can distinguish between VRP data being available
8830 and not available. */
8832 vr_phi_edge_counts
= NULL
;
8836 /* Main entry point to VRP (Value Range Propagation). This pass is
8837 loosely based on J. R. C. Patterson, ``Accurate Static Branch
8838 Prediction by Value Range Propagation,'' in SIGPLAN Conference on
8839 Programming Language Design and Implementation, pp. 67-78, 1995.
8840 Also available at http://citeseer.ist.psu.edu/patterson95accurate.html
8842 This is essentially an SSA-CCP pass modified to deal with ranges
8843 instead of constants.
8845 While propagating ranges, we may find that two or more SSA name
8846 have equivalent, though distinct ranges. For instance,
8849 2 p_4 = ASSERT_EXPR <p_3, p_3 != 0>
8851 4 p_5 = ASSERT_EXPR <p_4, p_4 == q_2>;
8855 In the code above, pointer p_5 has range [q_2, q_2], but from the
8856 code we can also determine that p_5 cannot be NULL and, if q_2 had
8857 a non-varying range, p_5's range should also be compatible with it.
8859 These equivalences are created by two expressions: ASSERT_EXPR and
8860 copy operations. Since p_5 is an assertion on p_4, and p_4 was the
8861 result of another assertion, then we can use the fact that p_5 and
8862 p_4 are equivalent when evaluating p_5's range.
8864 Together with value ranges, we also propagate these equivalences
8865 between names so that we can take advantage of information from
8866 multiple ranges when doing final replacement. Note that this
8867 equivalency relation is transitive but not symmetric.
8869 In the example above, p_5 is equivalent to p_4, q_2 and p_3, but we
8870 cannot assert that q_2 is equivalent to p_5 because q_2 may be used
8871 in contexts where that assertion does not hold (e.g., in line 6).
8873 TODO, the main difference between this pass and Patterson's is that
8874 we do not propagate edge probabilities. We only compute whether
8875 edges can be taken or not. That is, instead of having a spectrum
8876 of jump probabilities between 0 and 1, we only deal with 0, 1 and
8877 DON'T KNOW. In the future, it may be worthwhile to propagate
8878 probabilities to aid branch prediction. */
8887 loop_optimizer_init (LOOPS_NORMAL
| LOOPS_HAVE_RECORDED_EXITS
);
8888 rewrite_into_loop_closed_ssa (NULL
, TODO_update_ssa
);
8891 insert_range_assertions ();
8893 to_remove_edges
= VEC_alloc (edge
, heap
, 10);
8894 to_update_switch_stmts
= VEC_alloc (switch_update
, heap
, 5);
8895 threadedge_initialize_values ();
8898 ssa_propagate (vrp_visit_stmt
, vrp_visit_phi_node
);
8901 free_numbers_of_iterations_estimates ();
8903 /* ASSERT_EXPRs must be removed before finalizing jump threads
8904 as finalizing jump threads calls the CFG cleanup code which
8905 does not properly handle ASSERT_EXPRs. */
8906 remove_range_assertions ();
8908 /* If we exposed any new variables, go ahead and put them into
8909 SSA form now, before we handle jump threading. This simplifies
8910 interactions between rewriting of _DECL nodes into SSA form
8911 and rewriting SSA_NAME nodes into SSA form after block
8912 duplication and CFG manipulation. */
8913 update_ssa (TODO_update_ssa
);
8915 finalize_jump_threads ();
8917 /* Remove dead edges from SWITCH_EXPR optimization. This leaves the
8918 CFG in a broken state and requires a cfg_cleanup run. */
8919 FOR_EACH_VEC_ELT (edge
, to_remove_edges
, i
, e
)
8921 /* Update SWITCH_EXPR case label vector. */
8922 FOR_EACH_VEC_ELT (switch_update
, to_update_switch_stmts
, i
, su
)
8925 size_t n
= TREE_VEC_LENGTH (su
->vec
);
8927 gimple_switch_set_num_labels (su
->stmt
, n
);
8928 for (j
= 0; j
< n
; j
++)
8929 gimple_switch_set_label (su
->stmt
, j
, TREE_VEC_ELT (su
->vec
, j
));
8930 /* As we may have replaced the default label with a regular one
8931 make sure to make it a real default label again. This ensures
8932 optimal expansion. */
8933 label
= gimple_switch_default_label (su
->stmt
);
8934 CASE_LOW (label
) = NULL_TREE
;
8935 CASE_HIGH (label
) = NULL_TREE
;
8938 if (VEC_length (edge
, to_remove_edges
) > 0)
8939 free_dominance_info (CDI_DOMINATORS
);
8941 VEC_free (edge
, heap
, to_remove_edges
);
8942 VEC_free (switch_update
, heap
, to_update_switch_stmts
);
8943 threadedge_finalize_values ();
8946 loop_optimizer_finalize ();
8953 return flag_tree_vrp
!= 0;
8956 struct gimple_opt_pass pass_vrp
=
8961 gate_vrp
, /* gate */
8962 execute_vrp
, /* execute */
8965 0, /* static_pass_number */
8966 TV_TREE_VRP
, /* tv_id */
8967 PROP_ssa
, /* properties_required */
8968 0, /* properties_provided */
8969 0, /* properties_destroyed */
8970 0, /* todo_flags_start */
8975 | TODO_ggc_collect
/* todo_flags_finish */