1 /* Support routines for Value Range Propagation (VRP).
2 Copyright (C) 2005, 2006, 2007, 2008, 2009, 2010, 2011
3 Free Software Foundation, Inc.
4 Contributed by Diego Novillo <dnovillo@redhat.com>.
6 This file is part of GCC.
8 GCC is free software; you can redistribute it and/or modify
9 it under the terms of the GNU General Public License as published by
10 the Free Software Foundation; either version 3, or (at your option)
13 GCC is distributed in the hope that it will be useful,
14 but WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 GNU General Public License for more details.
18 You should have received a copy of the GNU General Public License
19 along with GCC; see the file COPYING3. If not see
20 <http://www.gnu.org/licenses/>. */
24 #include "coretypes.h"
29 #include "basic-block.h"
30 #include "tree-flow.h"
31 #include "tree-pass.h"
32 #include "tree-dump.h"
34 #include "tree-pretty-print.h"
35 #include "gimple-pretty-print.h"
36 #include "diagnostic-core.h"
39 #include "tree-scalar-evolution.h"
40 #include "tree-ssa-propagate.h"
41 #include "tree-chrec.h"
42 #include "gimple-fold.h"
47 /* Type of value ranges. See value_range_d for a description of these
49 enum value_range_type
{ VR_UNDEFINED
, VR_RANGE
, VR_ANTI_RANGE
, VR_VARYING
};
51 /* Range of values that can be associated with an SSA_NAME after VRP
55 /* Lattice value represented by this range. */
56 enum value_range_type type
;
58 /* Minimum and maximum values represented by this range. These
59 values should be interpreted as follows:
61 - If TYPE is VR_UNDEFINED or VR_VARYING then MIN and MAX must
64 - If TYPE == VR_RANGE then MIN holds the minimum value and
65 MAX holds the maximum value of the range [MIN, MAX].
67 - If TYPE == ANTI_RANGE the variable is known to NOT
68 take any values in the range [MIN, MAX]. */
72 /* Set of SSA names whose value ranges are equivalent to this one.
73 This set is only valid when TYPE is VR_RANGE or VR_ANTI_RANGE. */
77 typedef struct value_range_d value_range_t
;
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 tree
vrp_evaluate_conditional_warnv_with_ops (enum tree_code
,
97 tree
, tree
, bool, bool *,
100 /* Location information for ASSERT_EXPRs. Each instance of this
101 structure describes an ASSERT_EXPR for an SSA name. Since a single
102 SSA name may have more than one assertion associated with it, these
103 locations are kept in a linked list attached to the corresponding
105 struct assert_locus_d
107 /* Basic block where the assertion would be inserted. */
110 /* Some assertions need to be inserted on an edge (e.g., assertions
111 generated by COND_EXPRs). In those cases, BB will be NULL. */
114 /* Pointer to the statement that generated this assertion. */
115 gimple_stmt_iterator si
;
117 /* Predicate code for the ASSERT_EXPR. Must be COMPARISON_CLASS_P. */
118 enum tree_code comp_code
;
120 /* Value being compared against. */
123 /* Expression to compare. */
126 /* Next node in the linked list. */
127 struct assert_locus_d
*next
;
130 typedef struct assert_locus_d
*assert_locus_t
;
132 /* If bit I is present, it means that SSA name N_i has a list of
133 assertions that should be inserted in the IL. */
134 static bitmap need_assert_for
;
136 /* Array of locations lists where to insert assertions. ASSERTS_FOR[I]
137 holds a list of ASSERT_LOCUS_T nodes that describe where
138 ASSERT_EXPRs for SSA name N_I should be inserted. */
139 static assert_locus_t
*asserts_for
;
141 /* Value range array. After propagation, VR_VALUE[I] holds the range
142 of values that SSA name N_I may take. */
143 static unsigned num_vr_values
;
144 static value_range_t
**vr_value
;
145 static bool values_propagated
;
147 /* For a PHI node which sets SSA name N_I, VR_COUNTS[I] holds the
148 number of executable edges we saw the last time we visited the
150 static int *vr_phi_edge_counts
;
157 static VEC (edge
, heap
) *to_remove_edges
;
158 DEF_VEC_O(switch_update
);
159 DEF_VEC_ALLOC_O(switch_update
, heap
);
160 static VEC (switch_update
, heap
) *to_update_switch_stmts
;
163 /* Return the maximum value for TYPE. */
166 vrp_val_max (const_tree type
)
168 if (!INTEGRAL_TYPE_P (type
))
171 return TYPE_MAX_VALUE (type
);
174 /* Return the minimum value for TYPE. */
177 vrp_val_min (const_tree type
)
179 if (!INTEGRAL_TYPE_P (type
))
182 return TYPE_MIN_VALUE (type
);
185 /* Return whether VAL is equal to the maximum value of its type. This
186 will be true for a positive overflow infinity. We can't do a
187 simple equality comparison with TYPE_MAX_VALUE because C typedefs
188 and Ada subtypes can produce types whose TYPE_MAX_VALUE is not ==
189 to the integer constant with the same value in the type. */
192 vrp_val_is_max (const_tree val
)
194 tree type_max
= vrp_val_max (TREE_TYPE (val
));
195 return (val
== type_max
196 || (type_max
!= NULL_TREE
197 && operand_equal_p (val
, type_max
, 0)));
200 /* Return whether VAL is equal to the minimum value of its type. This
201 will be true for a negative overflow infinity. */
204 vrp_val_is_min (const_tree val
)
206 tree type_min
= vrp_val_min (TREE_TYPE (val
));
207 return (val
== type_min
208 || (type_min
!= NULL_TREE
209 && operand_equal_p (val
, type_min
, 0)));
213 /* Return whether TYPE should use an overflow infinity distinct from
214 TYPE_{MIN,MAX}_VALUE. We use an overflow infinity value to
215 represent a signed overflow during VRP computations. An infinity
216 is distinct from a half-range, which will go from some number to
217 TYPE_{MIN,MAX}_VALUE. */
220 needs_overflow_infinity (const_tree type
)
222 return INTEGRAL_TYPE_P (type
) && !TYPE_OVERFLOW_WRAPS (type
);
225 /* Return whether TYPE can support our overflow infinity
226 representation: we use the TREE_OVERFLOW flag, which only exists
227 for constants. If TYPE doesn't support this, we don't optimize
228 cases which would require signed overflow--we drop them to
232 supports_overflow_infinity (const_tree type
)
234 tree min
= vrp_val_min (type
), max
= vrp_val_max (type
);
235 #ifdef ENABLE_CHECKING
236 gcc_assert (needs_overflow_infinity (type
));
238 return (min
!= NULL_TREE
239 && CONSTANT_CLASS_P (min
)
241 && CONSTANT_CLASS_P (max
));
244 /* VAL is the maximum or minimum value of a type. Return a
245 corresponding overflow infinity. */
248 make_overflow_infinity (tree val
)
250 gcc_checking_assert (val
!= NULL_TREE
&& CONSTANT_CLASS_P (val
));
251 val
= copy_node (val
);
252 TREE_OVERFLOW (val
) = 1;
256 /* Return a negative overflow infinity for TYPE. */
259 negative_overflow_infinity (tree type
)
261 gcc_checking_assert (supports_overflow_infinity (type
));
262 return make_overflow_infinity (vrp_val_min (type
));
265 /* Return a positive overflow infinity for TYPE. */
268 positive_overflow_infinity (tree type
)
270 gcc_checking_assert (supports_overflow_infinity (type
));
271 return make_overflow_infinity (vrp_val_max (type
));
274 /* Return whether VAL is a negative overflow infinity. */
277 is_negative_overflow_infinity (const_tree val
)
279 return (needs_overflow_infinity (TREE_TYPE (val
))
280 && CONSTANT_CLASS_P (val
)
281 && TREE_OVERFLOW (val
)
282 && vrp_val_is_min (val
));
285 /* Return whether VAL is a positive overflow infinity. */
288 is_positive_overflow_infinity (const_tree val
)
290 return (needs_overflow_infinity (TREE_TYPE (val
))
291 && CONSTANT_CLASS_P (val
)
292 && TREE_OVERFLOW (val
)
293 && vrp_val_is_max (val
));
296 /* Return whether VAL is a positive or negative overflow infinity. */
299 is_overflow_infinity (const_tree val
)
301 return (needs_overflow_infinity (TREE_TYPE (val
))
302 && CONSTANT_CLASS_P (val
)
303 && TREE_OVERFLOW (val
)
304 && (vrp_val_is_min (val
) || vrp_val_is_max (val
)));
307 /* Return whether STMT has a constant rhs that is_overflow_infinity. */
310 stmt_overflow_infinity (gimple stmt
)
312 if (is_gimple_assign (stmt
)
313 && get_gimple_rhs_class (gimple_assign_rhs_code (stmt
)) ==
315 return is_overflow_infinity (gimple_assign_rhs1 (stmt
));
319 /* If VAL is now an overflow infinity, return VAL. Otherwise, return
320 the same value with TREE_OVERFLOW clear. This can be used to avoid
321 confusing a regular value with an overflow value. */
324 avoid_overflow_infinity (tree val
)
326 if (!is_overflow_infinity (val
))
329 if (vrp_val_is_max (val
))
330 return vrp_val_max (TREE_TYPE (val
));
333 gcc_checking_assert (vrp_val_is_min (val
));
334 return vrp_val_min (TREE_TYPE (val
));
339 /* Return true if ARG is marked with the nonnull attribute in the
340 current function signature. */
343 nonnull_arg_p (const_tree arg
)
345 tree t
, attrs
, fntype
;
346 unsigned HOST_WIDE_INT arg_num
;
348 gcc_assert (TREE_CODE (arg
) == PARM_DECL
&& POINTER_TYPE_P (TREE_TYPE (arg
)));
350 /* The static chain decl is always non null. */
351 if (arg
== cfun
->static_chain_decl
)
354 fntype
= TREE_TYPE (current_function_decl
);
355 attrs
= lookup_attribute ("nonnull", TYPE_ATTRIBUTES (fntype
));
357 /* If "nonnull" wasn't specified, we know nothing about the argument. */
358 if (attrs
== NULL_TREE
)
361 /* If "nonnull" applies to all the arguments, then ARG is non-null. */
362 if (TREE_VALUE (attrs
) == NULL_TREE
)
365 /* Get the position number for ARG in the function signature. */
366 for (arg_num
= 1, t
= DECL_ARGUMENTS (current_function_decl
);
368 t
= DECL_CHAIN (t
), arg_num
++)
374 gcc_assert (t
== arg
);
376 /* Now see if ARG_NUM is mentioned in the nonnull list. */
377 for (t
= TREE_VALUE (attrs
); t
; t
= TREE_CHAIN (t
))
379 if (compare_tree_int (TREE_VALUE (t
), arg_num
) == 0)
387 /* Set value range VR to VR_VARYING. */
390 set_value_range_to_varying (value_range_t
*vr
)
392 vr
->type
= VR_VARYING
;
393 vr
->min
= vr
->max
= NULL_TREE
;
395 bitmap_clear (vr
->equiv
);
399 /* Set value range VR to {T, MIN, MAX, EQUIV}. */
402 set_value_range (value_range_t
*vr
, enum value_range_type t
, tree min
,
403 tree max
, bitmap equiv
)
405 #if defined ENABLE_CHECKING
406 /* Check the validity of the range. */
407 if (t
== VR_RANGE
|| t
== VR_ANTI_RANGE
)
411 gcc_assert (min
&& max
);
413 if (INTEGRAL_TYPE_P (TREE_TYPE (min
)) && t
== VR_ANTI_RANGE
)
414 gcc_assert (!vrp_val_is_min (min
) || !vrp_val_is_max (max
));
416 cmp
= compare_values (min
, max
);
417 gcc_assert (cmp
== 0 || cmp
== -1 || cmp
== -2);
419 if (needs_overflow_infinity (TREE_TYPE (min
)))
420 gcc_assert (!is_overflow_infinity (min
)
421 || !is_overflow_infinity (max
));
424 if (t
== VR_UNDEFINED
|| t
== VR_VARYING
)
425 gcc_assert (min
== NULL_TREE
&& max
== NULL_TREE
);
427 if (t
== VR_UNDEFINED
|| t
== VR_VARYING
)
428 gcc_assert (equiv
== NULL
|| bitmap_empty_p (equiv
));
435 /* Since updating the equivalence set involves deep copying the
436 bitmaps, only do it if absolutely necessary. */
437 if (vr
->equiv
== NULL
439 vr
->equiv
= BITMAP_ALLOC (NULL
);
441 if (equiv
!= vr
->equiv
)
443 if (equiv
&& !bitmap_empty_p (equiv
))
444 bitmap_copy (vr
->equiv
, equiv
);
446 bitmap_clear (vr
->equiv
);
451 /* Set value range VR to the canonical form of {T, MIN, MAX, EQUIV}.
452 This means adjusting T, MIN and MAX representing the case of a
453 wrapping range with MAX < MIN covering [MIN, type_max] U [type_min, MAX]
454 as anti-rage ~[MAX+1, MIN-1]. Likewise for wrapping anti-ranges.
455 In corner cases where MAX+1 or MIN-1 wraps this will fall back
457 This routine exists to ease canonicalization in the case where we
458 extract ranges from var + CST op limit. */
461 set_and_canonicalize_value_range (value_range_t
*vr
, enum value_range_type t
,
462 tree min
, tree max
, bitmap equiv
)
464 /* Nothing to canonicalize for symbolic or unknown or varying ranges. */
466 && t
!= VR_ANTI_RANGE
)
467 || TREE_CODE (min
) != INTEGER_CST
468 || TREE_CODE (max
) != INTEGER_CST
)
470 set_value_range (vr
, t
, min
, max
, equiv
);
474 /* Wrong order for min and max, to swap them and the VR type we need
476 if (tree_int_cst_lt (max
, min
))
478 tree one
= build_int_cst (TREE_TYPE (min
), 1);
479 tree tmp
= int_const_binop (PLUS_EXPR
, max
, one
);
480 max
= int_const_binop (MINUS_EXPR
, min
, one
);
483 /* There's one corner case, if we had [C+1, C] before we now have
484 that again. But this represents an empty value range, so drop
485 to varying in this case. */
486 if (tree_int_cst_lt (max
, min
))
488 set_value_range_to_varying (vr
);
492 t
= t
== VR_RANGE
? VR_ANTI_RANGE
: VR_RANGE
;
495 /* Anti-ranges that can be represented as ranges should be so. */
496 if (t
== VR_ANTI_RANGE
)
498 bool is_min
= vrp_val_is_min (min
);
499 bool is_max
= vrp_val_is_max (max
);
501 if (is_min
&& is_max
)
503 /* We cannot deal with empty ranges, drop to varying. */
504 set_value_range_to_varying (vr
);
508 /* As a special exception preserve non-null ranges. */
509 && !(TYPE_UNSIGNED (TREE_TYPE (min
))
510 && integer_zerop (max
)))
512 tree one
= build_int_cst (TREE_TYPE (max
), 1);
513 min
= int_const_binop (PLUS_EXPR
, max
, one
);
514 max
= vrp_val_max (TREE_TYPE (max
));
519 tree one
= build_int_cst (TREE_TYPE (min
), 1);
520 max
= int_const_binop (MINUS_EXPR
, min
, one
);
521 min
= vrp_val_min (TREE_TYPE (min
));
526 set_value_range (vr
, t
, min
, max
, equiv
);
529 /* Copy value range FROM into value range TO. */
532 copy_value_range (value_range_t
*to
, value_range_t
*from
)
534 set_value_range (to
, from
->type
, from
->min
, from
->max
, from
->equiv
);
537 /* Set value range VR to a single value. This function is only called
538 with values we get from statements, and exists to clear the
539 TREE_OVERFLOW flag so that we don't think we have an overflow
540 infinity when we shouldn't. */
543 set_value_range_to_value (value_range_t
*vr
, tree val
, bitmap equiv
)
545 gcc_assert (is_gimple_min_invariant (val
));
546 val
= avoid_overflow_infinity (val
);
547 set_value_range (vr
, VR_RANGE
, val
, val
, equiv
);
550 /* Set value range VR to a non-negative range of type TYPE.
551 OVERFLOW_INFINITY indicates whether to use an overflow infinity
552 rather than TYPE_MAX_VALUE; this should be true if we determine
553 that the range is nonnegative based on the assumption that signed
554 overflow does not occur. */
557 set_value_range_to_nonnegative (value_range_t
*vr
, tree type
,
558 bool overflow_infinity
)
562 if (overflow_infinity
&& !supports_overflow_infinity (type
))
564 set_value_range_to_varying (vr
);
568 zero
= build_int_cst (type
, 0);
569 set_value_range (vr
, VR_RANGE
, zero
,
571 ? positive_overflow_infinity (type
)
572 : TYPE_MAX_VALUE (type
)),
576 /* Set value range VR to a non-NULL range of type TYPE. */
579 set_value_range_to_nonnull (value_range_t
*vr
, tree type
)
581 tree zero
= build_int_cst (type
, 0);
582 set_value_range (vr
, VR_ANTI_RANGE
, zero
, zero
, vr
->equiv
);
586 /* Set value range VR to a NULL range of type TYPE. */
589 set_value_range_to_null (value_range_t
*vr
, tree type
)
591 set_value_range_to_value (vr
, build_int_cst (type
, 0), vr
->equiv
);
595 /* Set value range VR to a range of a truthvalue of type TYPE. */
598 set_value_range_to_truthvalue (value_range_t
*vr
, tree type
)
600 if (TYPE_PRECISION (type
) == 1)
601 set_value_range_to_varying (vr
);
603 set_value_range (vr
, VR_RANGE
,
604 build_int_cst (type
, 0), build_int_cst (type
, 1),
609 /* Set value range VR to VR_UNDEFINED. */
612 set_value_range_to_undefined (value_range_t
*vr
)
614 vr
->type
= VR_UNDEFINED
;
615 vr
->min
= vr
->max
= NULL_TREE
;
617 bitmap_clear (vr
->equiv
);
621 /* If abs (min) < abs (max), set VR to [-max, max], if
622 abs (min) >= abs (max), set VR to [-min, min]. */
625 abs_extent_range (value_range_t
*vr
, tree min
, tree max
)
629 gcc_assert (TREE_CODE (min
) == INTEGER_CST
);
630 gcc_assert (TREE_CODE (max
) == INTEGER_CST
);
631 gcc_assert (INTEGRAL_TYPE_P (TREE_TYPE (min
)));
632 gcc_assert (!TYPE_UNSIGNED (TREE_TYPE (min
)));
633 min
= fold_unary (ABS_EXPR
, TREE_TYPE (min
), min
);
634 max
= fold_unary (ABS_EXPR
, TREE_TYPE (max
), max
);
635 if (TREE_OVERFLOW (min
) || TREE_OVERFLOW (max
))
637 set_value_range_to_varying (vr
);
640 cmp
= compare_values (min
, max
);
642 min
= fold_unary (NEGATE_EXPR
, TREE_TYPE (min
), max
);
643 else if (cmp
== 0 || cmp
== 1)
646 min
= fold_unary (NEGATE_EXPR
, TREE_TYPE (min
), min
);
650 set_value_range_to_varying (vr
);
653 set_and_canonicalize_value_range (vr
, VR_RANGE
, min
, max
, NULL
);
657 /* Return value range information for VAR.
659 If we have no values ranges recorded (ie, VRP is not running), then
660 return NULL. Otherwise create an empty range if none existed for VAR. */
662 static value_range_t
*
663 get_value_range (const_tree var
)
665 static const struct value_range_d vr_const_varying
666 = { VR_VARYING
, NULL_TREE
, NULL_TREE
, NULL
};
669 unsigned ver
= SSA_NAME_VERSION (var
);
671 /* If we have no recorded ranges, then return NULL. */
675 /* If we query the range for a new SSA name return an unmodifiable VARYING.
676 We should get here at most from the substitute-and-fold stage which
677 will never try to change values. */
678 if (ver
>= num_vr_values
)
679 return CONST_CAST (value_range_t
*, &vr_const_varying
);
685 /* After propagation finished do not allocate new value-ranges. */
686 if (values_propagated
)
687 return CONST_CAST (value_range_t
*, &vr_const_varying
);
689 /* Create a default value range. */
690 vr_value
[ver
] = vr
= XCNEW (value_range_t
);
692 /* Defer allocating the equivalence set. */
695 /* If VAR is a default definition of a parameter, the variable can
696 take any value in VAR's type. */
697 sym
= SSA_NAME_VAR (var
);
698 if (SSA_NAME_IS_DEFAULT_DEF (var
)
699 && TREE_CODE (sym
) == PARM_DECL
)
701 /* Try to use the "nonnull" attribute to create ~[0, 0]
702 anti-ranges for pointers. Note that this is only valid with
703 default definitions of PARM_DECLs. */
704 if (POINTER_TYPE_P (TREE_TYPE (sym
))
705 && nonnull_arg_p (sym
))
706 set_value_range_to_nonnull (vr
, TREE_TYPE (sym
));
708 set_value_range_to_varying (vr
);
714 /* Return true, if VAL1 and VAL2 are equal values for VRP purposes. */
717 vrp_operand_equal_p (const_tree val1
, const_tree val2
)
721 if (!val1
|| !val2
|| !operand_equal_p (val1
, val2
, 0))
723 if (is_overflow_infinity (val1
))
724 return is_overflow_infinity (val2
);
728 /* Return true, if the bitmaps B1 and B2 are equal. */
731 vrp_bitmap_equal_p (const_bitmap b1
, const_bitmap b2
)
734 || ((!b1
|| bitmap_empty_p (b1
))
735 && (!b2
|| bitmap_empty_p (b2
)))
737 && bitmap_equal_p (b1
, b2
)));
740 /* Update the value range and equivalence set for variable VAR to
741 NEW_VR. Return true if NEW_VR is different from VAR's previous
744 NOTE: This function assumes that NEW_VR is a temporary value range
745 object created for the sole purpose of updating VAR's range. The
746 storage used by the equivalence set from NEW_VR will be freed by
747 this function. Do not call update_value_range when NEW_VR
748 is the range object associated with another SSA name. */
751 update_value_range (const_tree var
, value_range_t
*new_vr
)
753 value_range_t
*old_vr
;
756 /* Update the value range, if necessary. */
757 old_vr
= get_value_range (var
);
758 is_new
= old_vr
->type
!= new_vr
->type
759 || !vrp_operand_equal_p (old_vr
->min
, new_vr
->min
)
760 || !vrp_operand_equal_p (old_vr
->max
, new_vr
->max
)
761 || !vrp_bitmap_equal_p (old_vr
->equiv
, new_vr
->equiv
);
764 set_value_range (old_vr
, new_vr
->type
, new_vr
->min
, new_vr
->max
,
767 BITMAP_FREE (new_vr
->equiv
);
773 /* Add VAR and VAR's equivalence set to EQUIV. This is the central
774 point where equivalence processing can be turned on/off. */
777 add_equivalence (bitmap
*equiv
, const_tree var
)
779 unsigned ver
= SSA_NAME_VERSION (var
);
780 value_range_t
*vr
= vr_value
[ver
];
783 *equiv
= BITMAP_ALLOC (NULL
);
784 bitmap_set_bit (*equiv
, ver
);
786 bitmap_ior_into (*equiv
, vr
->equiv
);
790 /* Return true if VR is ~[0, 0]. */
793 range_is_nonnull (value_range_t
*vr
)
795 return vr
->type
== VR_ANTI_RANGE
796 && integer_zerop (vr
->min
)
797 && integer_zerop (vr
->max
);
801 /* Return true if VR is [0, 0]. */
804 range_is_null (value_range_t
*vr
)
806 return vr
->type
== VR_RANGE
807 && integer_zerop (vr
->min
)
808 && integer_zerop (vr
->max
);
811 /* Return true if max and min of VR are INTEGER_CST. It's not necessary
815 range_int_cst_p (value_range_t
*vr
)
817 return (vr
->type
== VR_RANGE
818 && TREE_CODE (vr
->max
) == INTEGER_CST
819 && TREE_CODE (vr
->min
) == INTEGER_CST
820 && !TREE_OVERFLOW (vr
->max
)
821 && !TREE_OVERFLOW (vr
->min
));
824 /* Return true if VR is a INTEGER_CST singleton. */
827 range_int_cst_singleton_p (value_range_t
*vr
)
829 return (range_int_cst_p (vr
)
830 && tree_int_cst_equal (vr
->min
, vr
->max
));
833 /* Return true if value range VR involves at least one symbol. */
836 symbolic_range_p (value_range_t
*vr
)
838 return (!is_gimple_min_invariant (vr
->min
)
839 || !is_gimple_min_invariant (vr
->max
));
842 /* Return true if value range VR uses an overflow infinity. */
845 overflow_infinity_range_p (value_range_t
*vr
)
847 return (vr
->type
== VR_RANGE
848 && (is_overflow_infinity (vr
->min
)
849 || is_overflow_infinity (vr
->max
)));
852 /* Return false if we can not make a valid comparison based on VR;
853 this will be the case if it uses an overflow infinity and overflow
854 is not undefined (i.e., -fno-strict-overflow is in effect).
855 Otherwise return true, and set *STRICT_OVERFLOW_P to true if VR
856 uses an overflow infinity. */
859 usable_range_p (value_range_t
*vr
, bool *strict_overflow_p
)
861 gcc_assert (vr
->type
== VR_RANGE
);
862 if (is_overflow_infinity (vr
->min
))
864 *strict_overflow_p
= true;
865 if (!TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (vr
->min
)))
868 if (is_overflow_infinity (vr
->max
))
870 *strict_overflow_p
= true;
871 if (!TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (vr
->max
)))
878 /* Return true if the result of assignment STMT is know to be non-negative.
879 If the return value is based on the assumption that signed overflow is
880 undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't change
881 *STRICT_OVERFLOW_P.*/
884 gimple_assign_nonnegative_warnv_p (gimple stmt
, bool *strict_overflow_p
)
886 enum tree_code code
= gimple_assign_rhs_code (stmt
);
887 switch (get_gimple_rhs_class (code
))
889 case GIMPLE_UNARY_RHS
:
890 return tree_unary_nonnegative_warnv_p (gimple_assign_rhs_code (stmt
),
891 gimple_expr_type (stmt
),
892 gimple_assign_rhs1 (stmt
),
894 case GIMPLE_BINARY_RHS
:
895 return tree_binary_nonnegative_warnv_p (gimple_assign_rhs_code (stmt
),
896 gimple_expr_type (stmt
),
897 gimple_assign_rhs1 (stmt
),
898 gimple_assign_rhs2 (stmt
),
900 case GIMPLE_TERNARY_RHS
:
902 case GIMPLE_SINGLE_RHS
:
903 return tree_single_nonnegative_warnv_p (gimple_assign_rhs1 (stmt
),
905 case GIMPLE_INVALID_RHS
:
912 /* Return true if return value of call STMT is know to be non-negative.
913 If the return value is based on the assumption that signed overflow is
914 undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't change
915 *STRICT_OVERFLOW_P.*/
918 gimple_call_nonnegative_warnv_p (gimple stmt
, bool *strict_overflow_p
)
920 tree arg0
= gimple_call_num_args (stmt
) > 0 ?
921 gimple_call_arg (stmt
, 0) : NULL_TREE
;
922 tree arg1
= gimple_call_num_args (stmt
) > 1 ?
923 gimple_call_arg (stmt
, 1) : NULL_TREE
;
925 return tree_call_nonnegative_warnv_p (gimple_expr_type (stmt
),
926 gimple_call_fndecl (stmt
),
932 /* Return true if STMT is know to to compute a non-negative value.
933 If the return value is based on the assumption that signed overflow is
934 undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't change
935 *STRICT_OVERFLOW_P.*/
938 gimple_stmt_nonnegative_warnv_p (gimple stmt
, bool *strict_overflow_p
)
940 switch (gimple_code (stmt
))
943 return gimple_assign_nonnegative_warnv_p (stmt
, strict_overflow_p
);
945 return gimple_call_nonnegative_warnv_p (stmt
, strict_overflow_p
);
951 /* Return true if the result of assignment STMT is know to be non-zero.
952 If the return value is based on the assumption that signed overflow is
953 undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't change
954 *STRICT_OVERFLOW_P.*/
957 gimple_assign_nonzero_warnv_p (gimple stmt
, bool *strict_overflow_p
)
959 enum tree_code code
= gimple_assign_rhs_code (stmt
);
960 switch (get_gimple_rhs_class (code
))
962 case GIMPLE_UNARY_RHS
:
963 return tree_unary_nonzero_warnv_p (gimple_assign_rhs_code (stmt
),
964 gimple_expr_type (stmt
),
965 gimple_assign_rhs1 (stmt
),
967 case GIMPLE_BINARY_RHS
:
968 return tree_binary_nonzero_warnv_p (gimple_assign_rhs_code (stmt
),
969 gimple_expr_type (stmt
),
970 gimple_assign_rhs1 (stmt
),
971 gimple_assign_rhs2 (stmt
),
973 case GIMPLE_TERNARY_RHS
:
975 case GIMPLE_SINGLE_RHS
:
976 return tree_single_nonzero_warnv_p (gimple_assign_rhs1 (stmt
),
978 case GIMPLE_INVALID_RHS
:
985 /* Return true if STMT is know to to compute a non-zero value.
986 If the return value is based on the assumption that signed overflow is
987 undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't change
988 *STRICT_OVERFLOW_P.*/
991 gimple_stmt_nonzero_warnv_p (gimple stmt
, bool *strict_overflow_p
)
993 switch (gimple_code (stmt
))
996 return gimple_assign_nonzero_warnv_p (stmt
, strict_overflow_p
);
998 return gimple_alloca_call_p (stmt
);
1004 /* Like tree_expr_nonzero_warnv_p, but this function uses value ranges
1008 vrp_stmt_computes_nonzero (gimple stmt
, bool *strict_overflow_p
)
1010 if (gimple_stmt_nonzero_warnv_p (stmt
, strict_overflow_p
))
1013 /* If we have an expression of the form &X->a, then the expression
1014 is nonnull if X is nonnull. */
1015 if (is_gimple_assign (stmt
)
1016 && gimple_assign_rhs_code (stmt
) == ADDR_EXPR
)
1018 tree expr
= gimple_assign_rhs1 (stmt
);
1019 tree base
= get_base_address (TREE_OPERAND (expr
, 0));
1021 if (base
!= NULL_TREE
1022 && TREE_CODE (base
) == MEM_REF
1023 && TREE_CODE (TREE_OPERAND (base
, 0)) == SSA_NAME
)
1025 value_range_t
*vr
= get_value_range (TREE_OPERAND (base
, 0));
1026 if (range_is_nonnull (vr
))
1034 /* Returns true if EXPR is a valid value (as expected by compare_values) --
1035 a gimple invariant, or SSA_NAME +- CST. */
1038 valid_value_p (tree expr
)
1040 if (TREE_CODE (expr
) == SSA_NAME
)
1043 if (TREE_CODE (expr
) == PLUS_EXPR
1044 || TREE_CODE (expr
) == MINUS_EXPR
)
1045 return (TREE_CODE (TREE_OPERAND (expr
, 0)) == SSA_NAME
1046 && TREE_CODE (TREE_OPERAND (expr
, 1)) == INTEGER_CST
);
1048 return is_gimple_min_invariant (expr
);
1054 -2 if those are incomparable. */
1056 operand_less_p (tree val
, tree val2
)
1058 /* LT is folded faster than GE and others. Inline the common case. */
1059 if (TREE_CODE (val
) == INTEGER_CST
&& TREE_CODE (val2
) == INTEGER_CST
)
1061 if (TYPE_UNSIGNED (TREE_TYPE (val
)))
1062 return INT_CST_LT_UNSIGNED (val
, val2
);
1065 if (INT_CST_LT (val
, val2
))
1073 fold_defer_overflow_warnings ();
1075 tcmp
= fold_binary_to_constant (LT_EXPR
, boolean_type_node
, val
, val2
);
1077 fold_undefer_and_ignore_overflow_warnings ();
1080 || TREE_CODE (tcmp
) != INTEGER_CST
)
1083 if (!integer_zerop (tcmp
))
1087 /* val >= val2, not considering overflow infinity. */
1088 if (is_negative_overflow_infinity (val
))
1089 return is_negative_overflow_infinity (val2
) ? 0 : 1;
1090 else if (is_positive_overflow_infinity (val2
))
1091 return is_positive_overflow_infinity (val
) ? 0 : 1;
1096 /* Compare two values VAL1 and VAL2. Return
1098 -2 if VAL1 and VAL2 cannot be compared at compile-time,
1101 +1 if VAL1 > VAL2, and
1104 This is similar to tree_int_cst_compare but supports pointer values
1105 and values that cannot be compared at compile time.
1107 If STRICT_OVERFLOW_P is not NULL, then set *STRICT_OVERFLOW_P to
1108 true if the return value is only valid if we assume that signed
1109 overflow is undefined. */
1112 compare_values_warnv (tree val1
, tree val2
, bool *strict_overflow_p
)
1117 /* Below we rely on the fact that VAL1 and VAL2 are both pointers or
1119 gcc_assert (POINTER_TYPE_P (TREE_TYPE (val1
))
1120 == POINTER_TYPE_P (TREE_TYPE (val2
)));
1121 /* Convert the two values into the same type. This is needed because
1122 sizetype causes sign extension even for unsigned types. */
1123 val2
= fold_convert (TREE_TYPE (val1
), val2
);
1124 STRIP_USELESS_TYPE_CONVERSION (val2
);
1126 if ((TREE_CODE (val1
) == SSA_NAME
1127 || TREE_CODE (val1
) == PLUS_EXPR
1128 || TREE_CODE (val1
) == MINUS_EXPR
)
1129 && (TREE_CODE (val2
) == SSA_NAME
1130 || TREE_CODE (val2
) == PLUS_EXPR
1131 || TREE_CODE (val2
) == MINUS_EXPR
))
1133 tree n1
, c1
, n2
, c2
;
1134 enum tree_code code1
, code2
;
1136 /* If VAL1 and VAL2 are of the form 'NAME [+-] CST' or 'NAME',
1137 return -1 or +1 accordingly. If VAL1 and VAL2 don't use the
1138 same name, return -2. */
1139 if (TREE_CODE (val1
) == SSA_NAME
)
1147 code1
= TREE_CODE (val1
);
1148 n1
= TREE_OPERAND (val1
, 0);
1149 c1
= TREE_OPERAND (val1
, 1);
1150 if (tree_int_cst_sgn (c1
) == -1)
1152 if (is_negative_overflow_infinity (c1
))
1154 c1
= fold_unary_to_constant (NEGATE_EXPR
, TREE_TYPE (c1
), c1
);
1157 code1
= code1
== MINUS_EXPR
? PLUS_EXPR
: MINUS_EXPR
;
1161 if (TREE_CODE (val2
) == SSA_NAME
)
1169 code2
= TREE_CODE (val2
);
1170 n2
= TREE_OPERAND (val2
, 0);
1171 c2
= TREE_OPERAND (val2
, 1);
1172 if (tree_int_cst_sgn (c2
) == -1)
1174 if (is_negative_overflow_infinity (c2
))
1176 c2
= fold_unary_to_constant (NEGATE_EXPR
, TREE_TYPE (c2
), c2
);
1179 code2
= code2
== MINUS_EXPR
? PLUS_EXPR
: MINUS_EXPR
;
1183 /* Both values must use the same name. */
1187 if (code1
== SSA_NAME
1188 && code2
== SSA_NAME
)
1192 /* If overflow is defined we cannot simplify more. */
1193 if (!TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (val1
)))
1196 if (strict_overflow_p
!= NULL
1197 && (code1
== SSA_NAME
|| !TREE_NO_WARNING (val1
))
1198 && (code2
== SSA_NAME
|| !TREE_NO_WARNING (val2
)))
1199 *strict_overflow_p
= true;
1201 if (code1
== SSA_NAME
)
1203 if (code2
== PLUS_EXPR
)
1204 /* NAME < NAME + CST */
1206 else if (code2
== MINUS_EXPR
)
1207 /* NAME > NAME - CST */
1210 else if (code1
== PLUS_EXPR
)
1212 if (code2
== SSA_NAME
)
1213 /* NAME + CST > NAME */
1215 else if (code2
== PLUS_EXPR
)
1216 /* NAME + CST1 > NAME + CST2, if CST1 > CST2 */
1217 return compare_values_warnv (c1
, c2
, strict_overflow_p
);
1218 else if (code2
== MINUS_EXPR
)
1219 /* NAME + CST1 > NAME - CST2 */
1222 else if (code1
== MINUS_EXPR
)
1224 if (code2
== SSA_NAME
)
1225 /* NAME - CST < NAME */
1227 else if (code2
== PLUS_EXPR
)
1228 /* NAME - CST1 < NAME + CST2 */
1230 else if (code2
== MINUS_EXPR
)
1231 /* NAME - CST1 > NAME - CST2, if CST1 < CST2. Notice that
1232 C1 and C2 are swapped in the call to compare_values. */
1233 return compare_values_warnv (c2
, c1
, strict_overflow_p
);
1239 /* We cannot compare non-constants. */
1240 if (!is_gimple_min_invariant (val1
) || !is_gimple_min_invariant (val2
))
1243 if (!POINTER_TYPE_P (TREE_TYPE (val1
)))
1245 /* We cannot compare overflowed values, except for overflow
1247 if (TREE_OVERFLOW (val1
) || TREE_OVERFLOW (val2
))
1249 if (strict_overflow_p
!= NULL
)
1250 *strict_overflow_p
= true;
1251 if (is_negative_overflow_infinity (val1
))
1252 return is_negative_overflow_infinity (val2
) ? 0 : -1;
1253 else if (is_negative_overflow_infinity (val2
))
1255 else if (is_positive_overflow_infinity (val1
))
1256 return is_positive_overflow_infinity (val2
) ? 0 : 1;
1257 else if (is_positive_overflow_infinity (val2
))
1262 return tree_int_cst_compare (val1
, val2
);
1268 /* First see if VAL1 and VAL2 are not the same. */
1269 if (val1
== val2
|| operand_equal_p (val1
, val2
, 0))
1272 /* If VAL1 is a lower address than VAL2, return -1. */
1273 if (operand_less_p (val1
, val2
) == 1)
1276 /* If VAL1 is a higher address than VAL2, return +1. */
1277 if (operand_less_p (val2
, val1
) == 1)
1280 /* If VAL1 is different than VAL2, return +2.
1281 For integer constants we either have already returned -1 or 1
1282 or they are equivalent. We still might succeed in proving
1283 something about non-trivial operands. */
1284 if (TREE_CODE (val1
) != INTEGER_CST
1285 || TREE_CODE (val2
) != INTEGER_CST
)
1287 t
= fold_binary_to_constant (NE_EXPR
, boolean_type_node
, val1
, val2
);
1288 if (t
&& integer_onep (t
))
1296 /* Compare values like compare_values_warnv, but treat comparisons of
1297 nonconstants which rely on undefined overflow as incomparable. */
1300 compare_values (tree val1
, tree val2
)
1306 ret
= compare_values_warnv (val1
, val2
, &sop
);
1308 && (!is_gimple_min_invariant (val1
) || !is_gimple_min_invariant (val2
)))
1314 /* Return 1 if VAL is inside value range VR (VR->MIN <= VAL <= VR->MAX),
1315 0 if VAL is not inside VR,
1316 -2 if we cannot tell either way.
1318 FIXME, the current semantics of this functions are a bit quirky
1319 when taken in the context of VRP. In here we do not care
1320 about VR's type. If VR is the anti-range ~[3, 5] the call
1321 value_inside_range (4, VR) will return 1.
1323 This is counter-intuitive in a strict sense, but the callers
1324 currently expect this. They are calling the function
1325 merely to determine whether VR->MIN <= VAL <= VR->MAX. The
1326 callers are applying the VR_RANGE/VR_ANTI_RANGE semantics
1329 This also applies to value_ranges_intersect_p and
1330 range_includes_zero_p. The semantics of VR_RANGE and
1331 VR_ANTI_RANGE should be encoded here, but that also means
1332 adapting the users of these functions to the new semantics.
1334 Benchmark compile/20001226-1.c compilation time after changing this
1338 value_inside_range (tree val
, value_range_t
* vr
)
1342 cmp1
= operand_less_p (val
, vr
->min
);
1348 cmp2
= operand_less_p (vr
->max
, val
);
1356 /* Return true if value ranges VR0 and VR1 have a non-empty
1359 Benchmark compile/20001226-1.c compilation time after changing this
1364 value_ranges_intersect_p (value_range_t
*vr0
, value_range_t
*vr1
)
1366 /* The value ranges do not intersect if the maximum of the first range is
1367 less than the minimum of the second range or vice versa.
1368 When those relations are unknown, we can't do any better. */
1369 if (operand_less_p (vr0
->max
, vr1
->min
) != 0)
1371 if (operand_less_p (vr1
->max
, vr0
->min
) != 0)
1377 /* Return true if VR includes the value zero, false otherwise. FIXME,
1378 currently this will return false for an anti-range like ~[-4, 3].
1379 This will be wrong when the semantics of value_inside_range are
1380 modified (currently the users of this function expect these
1384 range_includes_zero_p (value_range_t
*vr
)
1388 gcc_assert (vr
->type
!= VR_UNDEFINED
1389 && vr
->type
!= VR_VARYING
1390 && !symbolic_range_p (vr
));
1392 zero
= build_int_cst (TREE_TYPE (vr
->min
), 0);
1393 return (value_inside_range (zero
, vr
) == 1);
1396 /* Return true if *VR is know to only contain nonnegative values. */
1399 value_range_nonnegative_p (value_range_t
*vr
)
1401 /* Testing for VR_ANTI_RANGE is not useful here as any anti-range
1402 which would return a useful value should be encoded as a
1404 if (vr
->type
== VR_RANGE
)
1406 int result
= compare_values (vr
->min
, integer_zero_node
);
1407 return (result
== 0 || result
== 1);
1413 /* Return true if T, an SSA_NAME, is known to be nonnegative. Return
1414 false otherwise or if no value range information is available. */
1417 ssa_name_nonnegative_p (const_tree t
)
1419 value_range_t
*vr
= get_value_range (t
);
1421 if (INTEGRAL_TYPE_P (t
)
1422 && TYPE_UNSIGNED (t
))
1428 return value_range_nonnegative_p (vr
);
1431 /* If *VR has a value rante that is a single constant value return that,
1432 otherwise return NULL_TREE. */
1435 value_range_constant_singleton (value_range_t
*vr
)
1437 if (vr
->type
== VR_RANGE
1438 && operand_equal_p (vr
->min
, vr
->max
, 0)
1439 && is_gimple_min_invariant (vr
->min
))
1445 /* If OP has a value range with a single constant value return that,
1446 otherwise return NULL_TREE. This returns OP itself if OP is a
1450 op_with_constant_singleton_value_range (tree op
)
1452 if (is_gimple_min_invariant (op
))
1455 if (TREE_CODE (op
) != SSA_NAME
)
1458 return value_range_constant_singleton (get_value_range (op
));
1461 /* Return true if op is in a boolean [0, 1] value-range. */
1464 op_with_boolean_value_range_p (tree op
)
1468 if (TYPE_PRECISION (TREE_TYPE (op
)) == 1)
1471 if (integer_zerop (op
)
1472 || integer_onep (op
))
1475 if (TREE_CODE (op
) != SSA_NAME
)
1478 vr
= get_value_range (op
);
1479 return (vr
->type
== VR_RANGE
1480 && integer_zerop (vr
->min
)
1481 && integer_onep (vr
->max
));
1484 /* Extract value range information from an ASSERT_EXPR EXPR and store
1488 extract_range_from_assert (value_range_t
*vr_p
, tree expr
)
1490 tree var
, cond
, limit
, min
, max
, type
;
1491 value_range_t
*var_vr
, *limit_vr
;
1492 enum tree_code cond_code
;
1494 var
= ASSERT_EXPR_VAR (expr
);
1495 cond
= ASSERT_EXPR_COND (expr
);
1497 gcc_assert (COMPARISON_CLASS_P (cond
));
1499 /* Find VAR in the ASSERT_EXPR conditional. */
1500 if (var
== TREE_OPERAND (cond
, 0)
1501 || TREE_CODE (TREE_OPERAND (cond
, 0)) == PLUS_EXPR
1502 || TREE_CODE (TREE_OPERAND (cond
, 0)) == NOP_EXPR
)
1504 /* If the predicate is of the form VAR COMP LIMIT, then we just
1505 take LIMIT from the RHS and use the same comparison code. */
1506 cond_code
= TREE_CODE (cond
);
1507 limit
= TREE_OPERAND (cond
, 1);
1508 cond
= TREE_OPERAND (cond
, 0);
1512 /* If the predicate is of the form LIMIT COMP VAR, then we need
1513 to flip around the comparison code to create the proper range
1515 cond_code
= swap_tree_comparison (TREE_CODE (cond
));
1516 limit
= TREE_OPERAND (cond
, 0);
1517 cond
= TREE_OPERAND (cond
, 1);
1520 limit
= avoid_overflow_infinity (limit
);
1522 type
= TREE_TYPE (limit
);
1523 gcc_assert (limit
!= var
);
1525 /* For pointer arithmetic, we only keep track of pointer equality
1527 if (POINTER_TYPE_P (type
) && cond_code
!= NE_EXPR
&& cond_code
!= EQ_EXPR
)
1529 set_value_range_to_varying (vr_p
);
1533 /* If LIMIT is another SSA name and LIMIT has a range of its own,
1534 try to use LIMIT's range to avoid creating symbolic ranges
1536 limit_vr
= (TREE_CODE (limit
) == SSA_NAME
) ? get_value_range (limit
) : NULL
;
1538 /* LIMIT's range is only interesting if it has any useful information. */
1540 && (limit_vr
->type
== VR_UNDEFINED
1541 || limit_vr
->type
== VR_VARYING
1542 || symbolic_range_p (limit_vr
)))
1545 /* Initially, the new range has the same set of equivalences of
1546 VAR's range. This will be revised before returning the final
1547 value. Since assertions may be chained via mutually exclusive
1548 predicates, we will need to trim the set of equivalences before
1550 gcc_assert (vr_p
->equiv
== NULL
);
1551 add_equivalence (&vr_p
->equiv
, var
);
1553 /* Extract a new range based on the asserted comparison for VAR and
1554 LIMIT's value range. Notice that if LIMIT has an anti-range, we
1555 will only use it for equality comparisons (EQ_EXPR). For any
1556 other kind of assertion, we cannot derive a range from LIMIT's
1557 anti-range that can be used to describe the new range. For
1558 instance, ASSERT_EXPR <x_2, x_2 <= b_4>. If b_4 is ~[2, 10],
1559 then b_4 takes on the ranges [-INF, 1] and [11, +INF]. There is
1560 no single range for x_2 that could describe LE_EXPR, so we might
1561 as well build the range [b_4, +INF] for it.
1562 One special case we handle is extracting a range from a
1563 range test encoded as (unsigned)var + CST <= limit. */
1564 if (TREE_CODE (cond
) == NOP_EXPR
1565 || TREE_CODE (cond
) == PLUS_EXPR
)
1567 if (TREE_CODE (cond
) == PLUS_EXPR
)
1569 min
= fold_build1 (NEGATE_EXPR
, TREE_TYPE (TREE_OPERAND (cond
, 1)),
1570 TREE_OPERAND (cond
, 1));
1571 max
= int_const_binop (PLUS_EXPR
, limit
, min
);
1572 cond
= TREE_OPERAND (cond
, 0);
1576 min
= build_int_cst (TREE_TYPE (var
), 0);
1580 /* Make sure to not set TREE_OVERFLOW on the final type
1581 conversion. We are willingly interpreting large positive
1582 unsigned values as negative singed values here. */
1583 min
= force_fit_type_double (TREE_TYPE (var
), tree_to_double_int (min
),
1585 max
= force_fit_type_double (TREE_TYPE (var
), tree_to_double_int (max
),
1588 /* We can transform a max, min range to an anti-range or
1589 vice-versa. Use set_and_canonicalize_value_range which does
1591 if (cond_code
== LE_EXPR
)
1592 set_and_canonicalize_value_range (vr_p
, VR_RANGE
,
1593 min
, max
, vr_p
->equiv
);
1594 else if (cond_code
== GT_EXPR
)
1595 set_and_canonicalize_value_range (vr_p
, VR_ANTI_RANGE
,
1596 min
, max
, vr_p
->equiv
);
1600 else if (cond_code
== EQ_EXPR
)
1602 enum value_range_type range_type
;
1606 range_type
= limit_vr
->type
;
1607 min
= limit_vr
->min
;
1608 max
= limit_vr
->max
;
1612 range_type
= VR_RANGE
;
1617 set_value_range (vr_p
, range_type
, min
, max
, vr_p
->equiv
);
1619 /* When asserting the equality VAR == LIMIT and LIMIT is another
1620 SSA name, the new range will also inherit the equivalence set
1622 if (TREE_CODE (limit
) == SSA_NAME
)
1623 add_equivalence (&vr_p
->equiv
, limit
);
1625 else if (cond_code
== NE_EXPR
)
1627 /* As described above, when LIMIT's range is an anti-range and
1628 this assertion is an inequality (NE_EXPR), then we cannot
1629 derive anything from the anti-range. For instance, if
1630 LIMIT's range was ~[0, 0], the assertion 'VAR != LIMIT' does
1631 not imply that VAR's range is [0, 0]. So, in the case of
1632 anti-ranges, we just assert the inequality using LIMIT and
1635 If LIMIT_VR is a range, we can only use it to build a new
1636 anti-range if LIMIT_VR is a single-valued range. For
1637 instance, if LIMIT_VR is [0, 1], the predicate
1638 VAR != [0, 1] does not mean that VAR's range is ~[0, 1].
1639 Rather, it means that for value 0 VAR should be ~[0, 0]
1640 and for value 1, VAR should be ~[1, 1]. We cannot
1641 represent these ranges.
1643 The only situation in which we can build a valid
1644 anti-range is when LIMIT_VR is a single-valued range
1645 (i.e., LIMIT_VR->MIN == LIMIT_VR->MAX). In that case,
1646 build the anti-range ~[LIMIT_VR->MIN, LIMIT_VR->MAX]. */
1648 && limit_vr
->type
== VR_RANGE
1649 && compare_values (limit_vr
->min
, limit_vr
->max
) == 0)
1651 min
= limit_vr
->min
;
1652 max
= limit_vr
->max
;
1656 /* In any other case, we cannot use LIMIT's range to build a
1657 valid anti-range. */
1661 /* If MIN and MAX cover the whole range for their type, then
1662 just use the original LIMIT. */
1663 if (INTEGRAL_TYPE_P (type
)
1664 && vrp_val_is_min (min
)
1665 && vrp_val_is_max (max
))
1668 set_value_range (vr_p
, VR_ANTI_RANGE
, min
, max
, vr_p
->equiv
);
1670 else if (cond_code
== LE_EXPR
|| cond_code
== LT_EXPR
)
1672 min
= TYPE_MIN_VALUE (type
);
1674 if (limit_vr
== NULL
|| limit_vr
->type
== VR_ANTI_RANGE
)
1678 /* If LIMIT_VR is of the form [N1, N2], we need to build the
1679 range [MIN, N2] for LE_EXPR and [MIN, N2 - 1] for
1681 max
= limit_vr
->max
;
1684 /* If the maximum value forces us to be out of bounds, simply punt.
1685 It would be pointless to try and do anything more since this
1686 all should be optimized away above us. */
1687 if ((cond_code
== LT_EXPR
1688 && compare_values (max
, min
) == 0)
1689 || (CONSTANT_CLASS_P (max
) && TREE_OVERFLOW (max
)))
1690 set_value_range_to_varying (vr_p
);
1693 /* For LT_EXPR, we create the range [MIN, MAX - 1]. */
1694 if (cond_code
== LT_EXPR
)
1696 tree one
= build_int_cst (type
, 1);
1697 max
= fold_build2 (MINUS_EXPR
, type
, max
, one
);
1699 TREE_NO_WARNING (max
) = 1;
1702 set_value_range (vr_p
, VR_RANGE
, min
, max
, vr_p
->equiv
);
1705 else if (cond_code
== GE_EXPR
|| cond_code
== GT_EXPR
)
1707 max
= TYPE_MAX_VALUE (type
);
1709 if (limit_vr
== NULL
|| limit_vr
->type
== VR_ANTI_RANGE
)
1713 /* If LIMIT_VR is of the form [N1, N2], we need to build the
1714 range [N1, MAX] for GE_EXPR and [N1 + 1, MAX] for
1716 min
= limit_vr
->min
;
1719 /* If the minimum value forces us to be out of bounds, simply punt.
1720 It would be pointless to try and do anything more since this
1721 all should be optimized away above us. */
1722 if ((cond_code
== GT_EXPR
1723 && compare_values (min
, max
) == 0)
1724 || (CONSTANT_CLASS_P (min
) && TREE_OVERFLOW (min
)))
1725 set_value_range_to_varying (vr_p
);
1728 /* For GT_EXPR, we create the range [MIN + 1, MAX]. */
1729 if (cond_code
== GT_EXPR
)
1731 tree one
= build_int_cst (type
, 1);
1732 min
= fold_build2 (PLUS_EXPR
, type
, min
, one
);
1734 TREE_NO_WARNING (min
) = 1;
1737 set_value_range (vr_p
, VR_RANGE
, min
, max
, vr_p
->equiv
);
1743 /* If VAR already had a known range, it may happen that the new
1744 range we have computed and VAR's range are not compatible. For
1748 p_6 = ASSERT_EXPR <p_5, p_5 == NULL>;
1750 p_8 = ASSERT_EXPR <p_6, p_6 != NULL>;
1752 While the above comes from a faulty program, it will cause an ICE
1753 later because p_8 and p_6 will have incompatible ranges and at
1754 the same time will be considered equivalent. A similar situation
1758 i_6 = ASSERT_EXPR <i_5, i_5 > 10>;
1760 i_7 = ASSERT_EXPR <i_6, i_6 < 5>;
1762 Again i_6 and i_7 will have incompatible ranges. It would be
1763 pointless to try and do anything with i_7's range because
1764 anything dominated by 'if (i_5 < 5)' will be optimized away.
1765 Note, due to the wa in which simulation proceeds, the statement
1766 i_7 = ASSERT_EXPR <...> we would never be visited because the
1767 conditional 'if (i_5 < 5)' always evaluates to false. However,
1768 this extra check does not hurt and may protect against future
1769 changes to VRP that may get into a situation similar to the
1770 NULL pointer dereference example.
1772 Note that these compatibility tests are only needed when dealing
1773 with ranges or a mix of range and anti-range. If VAR_VR and VR_P
1774 are both anti-ranges, they will always be compatible, because two
1775 anti-ranges will always have a non-empty intersection. */
1777 var_vr
= get_value_range (var
);
1779 /* We may need to make adjustments when VR_P and VAR_VR are numeric
1780 ranges or anti-ranges. */
1781 if (vr_p
->type
== VR_VARYING
1782 || vr_p
->type
== VR_UNDEFINED
1783 || var_vr
->type
== VR_VARYING
1784 || var_vr
->type
== VR_UNDEFINED
1785 || symbolic_range_p (vr_p
)
1786 || symbolic_range_p (var_vr
))
1789 if (var_vr
->type
== VR_RANGE
&& vr_p
->type
== VR_RANGE
)
1791 /* If the two ranges have a non-empty intersection, we can
1792 refine the resulting range. Since the assert expression
1793 creates an equivalency and at the same time it asserts a
1794 predicate, we can take the intersection of the two ranges to
1795 get better precision. */
1796 if (value_ranges_intersect_p (var_vr
, vr_p
))
1798 /* Use the larger of the two minimums. */
1799 if (compare_values (vr_p
->min
, var_vr
->min
) == -1)
1804 /* Use the smaller of the two maximums. */
1805 if (compare_values (vr_p
->max
, var_vr
->max
) == 1)
1810 set_value_range (vr_p
, vr_p
->type
, min
, max
, vr_p
->equiv
);
1814 /* The two ranges do not intersect, set the new range to
1815 VARYING, because we will not be able to do anything
1816 meaningful with it. */
1817 set_value_range_to_varying (vr_p
);
1820 else if ((var_vr
->type
== VR_RANGE
&& vr_p
->type
== VR_ANTI_RANGE
)
1821 || (var_vr
->type
== VR_ANTI_RANGE
&& vr_p
->type
== VR_RANGE
))
1823 /* A range and an anti-range will cancel each other only if
1824 their ends are the same. For instance, in the example above,
1825 p_8's range ~[0, 0] and p_6's range [0, 0] are incompatible,
1826 so VR_P should be set to VR_VARYING. */
1827 if (compare_values (var_vr
->min
, vr_p
->min
) == 0
1828 && compare_values (var_vr
->max
, vr_p
->max
) == 0)
1829 set_value_range_to_varying (vr_p
);
1832 tree min
, max
, anti_min
, anti_max
, real_min
, real_max
;
1835 /* We want to compute the logical AND of the two ranges;
1836 there are three cases to consider.
1839 1. The VR_ANTI_RANGE range is completely within the
1840 VR_RANGE and the endpoints of the ranges are
1841 different. In that case the resulting range
1842 should be whichever range is more precise.
1843 Typically that will be the VR_RANGE.
1845 2. The VR_ANTI_RANGE is completely disjoint from
1846 the VR_RANGE. In this case the resulting range
1847 should be the VR_RANGE.
1849 3. There is some overlap between the VR_ANTI_RANGE
1852 3a. If the high limit of the VR_ANTI_RANGE resides
1853 within the VR_RANGE, then the result is a new
1854 VR_RANGE starting at the high limit of the
1855 VR_ANTI_RANGE + 1 and extending to the
1856 high limit of the original VR_RANGE.
1858 3b. If the low limit of the VR_ANTI_RANGE resides
1859 within the VR_RANGE, then the result is a new
1860 VR_RANGE starting at the low limit of the original
1861 VR_RANGE and extending to the low limit of the
1862 VR_ANTI_RANGE - 1. */
1863 if (vr_p
->type
== VR_ANTI_RANGE
)
1865 anti_min
= vr_p
->min
;
1866 anti_max
= vr_p
->max
;
1867 real_min
= var_vr
->min
;
1868 real_max
= var_vr
->max
;
1872 anti_min
= var_vr
->min
;
1873 anti_max
= var_vr
->max
;
1874 real_min
= vr_p
->min
;
1875 real_max
= vr_p
->max
;
1879 /* Case 1, VR_ANTI_RANGE completely within VR_RANGE,
1880 not including any endpoints. */
1881 if (compare_values (anti_max
, real_max
) == -1
1882 && compare_values (anti_min
, real_min
) == 1)
1884 /* If the range is covering the whole valid range of
1885 the type keep the anti-range. */
1886 if (!vrp_val_is_min (real_min
)
1887 || !vrp_val_is_max (real_max
))
1888 set_value_range (vr_p
, VR_RANGE
, real_min
,
1889 real_max
, vr_p
->equiv
);
1891 /* Case 2, VR_ANTI_RANGE completely disjoint from
1893 else if (compare_values (anti_min
, real_max
) == 1
1894 || compare_values (anti_max
, real_min
) == -1)
1896 set_value_range (vr_p
, VR_RANGE
, real_min
,
1897 real_max
, vr_p
->equiv
);
1899 /* Case 3a, the anti-range extends into the low
1900 part of the real range. Thus creating a new
1901 low for the real range. */
1902 else if (((cmp
= compare_values (anti_max
, real_min
)) == 1
1904 && compare_values (anti_max
, real_max
) == -1)
1906 gcc_assert (!is_positive_overflow_infinity (anti_max
));
1907 if (needs_overflow_infinity (TREE_TYPE (anti_max
))
1908 && vrp_val_is_max (anti_max
))
1910 if (!supports_overflow_infinity (TREE_TYPE (var_vr
->min
)))
1912 set_value_range_to_varying (vr_p
);
1915 min
= positive_overflow_infinity (TREE_TYPE (var_vr
->min
));
1917 else if (!POINTER_TYPE_P (TREE_TYPE (var_vr
->min
)))
1918 min
= fold_build2 (PLUS_EXPR
, TREE_TYPE (var_vr
->min
),
1920 build_int_cst (TREE_TYPE (var_vr
->min
), 1));
1922 min
= fold_build_pointer_plus_hwi (anti_max
, 1);
1924 set_value_range (vr_p
, VR_RANGE
, min
, max
, vr_p
->equiv
);
1926 /* Case 3b, the anti-range extends into the high
1927 part of the real range. Thus creating a new
1928 higher for the real range. */
1929 else if (compare_values (anti_min
, real_min
) == 1
1930 && ((cmp
= compare_values (anti_min
, real_max
)) == -1
1933 gcc_assert (!is_negative_overflow_infinity (anti_min
));
1934 if (needs_overflow_infinity (TREE_TYPE (anti_min
))
1935 && vrp_val_is_min (anti_min
))
1937 if (!supports_overflow_infinity (TREE_TYPE (var_vr
->min
)))
1939 set_value_range_to_varying (vr_p
);
1942 max
= negative_overflow_infinity (TREE_TYPE (var_vr
->min
));
1944 else if (!POINTER_TYPE_P (TREE_TYPE (var_vr
->min
)))
1945 max
= fold_build2 (MINUS_EXPR
, TREE_TYPE (var_vr
->min
),
1947 build_int_cst (TREE_TYPE (var_vr
->min
), 1));
1949 max
= fold_build_pointer_plus_hwi (anti_min
, -1);
1951 set_value_range (vr_p
, VR_RANGE
, min
, max
, vr_p
->equiv
);
1958 /* Extract range information from SSA name VAR and store it in VR. If
1959 VAR has an interesting range, use it. Otherwise, create the
1960 range [VAR, VAR] and return it. This is useful in situations where
1961 we may have conditionals testing values of VARYING names. For
1968 Even if y_5 is deemed VARYING, we can determine that x_3 > y_5 is
1972 extract_range_from_ssa_name (value_range_t
*vr
, tree var
)
1974 value_range_t
*var_vr
= get_value_range (var
);
1976 if (var_vr
->type
!= VR_UNDEFINED
&& var_vr
->type
!= VR_VARYING
)
1977 copy_value_range (vr
, var_vr
);
1979 set_value_range (vr
, VR_RANGE
, var
, var
, NULL
);
1981 add_equivalence (&vr
->equiv
, var
);
1985 /* Wrapper around int_const_binop. If the operation overflows and we
1986 are not using wrapping arithmetic, then adjust the result to be
1987 -INF or +INF depending on CODE, VAL1 and VAL2. This can return
1988 NULL_TREE if we need to use an overflow infinity representation but
1989 the type does not support it. */
1992 vrp_int_const_binop (enum tree_code code
, tree val1
, tree val2
)
1996 res
= int_const_binop (code
, val1
, val2
);
1998 /* If we are using unsigned arithmetic, operate symbolically
1999 on -INF and +INF as int_const_binop only handles signed overflow. */
2000 if (TYPE_UNSIGNED (TREE_TYPE (val1
)))
2002 int checkz
= compare_values (res
, val1
);
2003 bool overflow
= false;
2005 /* Ensure that res = val1 [+*] val2 >= val1
2006 or that res = val1 - val2 <= val1. */
2007 if ((code
== PLUS_EXPR
2008 && !(checkz
== 1 || checkz
== 0))
2009 || (code
== MINUS_EXPR
2010 && !(checkz
== 0 || checkz
== -1)))
2014 /* Checking for multiplication overflow is done by dividing the
2015 output of the multiplication by the first input of the
2016 multiplication. If the result of that division operation is
2017 not equal to the second input of the multiplication, then the
2018 multiplication overflowed. */
2019 else if (code
== MULT_EXPR
&& !integer_zerop (val1
))
2021 tree tmp
= int_const_binop (TRUNC_DIV_EXPR
,
2024 int check
= compare_values (tmp
, val2
);
2032 res
= copy_node (res
);
2033 TREE_OVERFLOW (res
) = 1;
2037 else if (TYPE_OVERFLOW_WRAPS (TREE_TYPE (val1
)))
2038 /* If the singed operation wraps then int_const_binop has done
2039 everything we want. */
2041 else if ((TREE_OVERFLOW (res
)
2042 && !TREE_OVERFLOW (val1
)
2043 && !TREE_OVERFLOW (val2
))
2044 || is_overflow_infinity (val1
)
2045 || is_overflow_infinity (val2
))
2047 /* If the operation overflowed but neither VAL1 nor VAL2 are
2048 overflown, return -INF or +INF depending on the operation
2049 and the combination of signs of the operands. */
2050 int sgn1
= tree_int_cst_sgn (val1
);
2051 int sgn2
= tree_int_cst_sgn (val2
);
2053 if (needs_overflow_infinity (TREE_TYPE (res
))
2054 && !supports_overflow_infinity (TREE_TYPE (res
)))
2057 /* We have to punt on adding infinities of different signs,
2058 since we can't tell what the sign of the result should be.
2059 Likewise for subtracting infinities of the same sign. */
2060 if (((code
== PLUS_EXPR
&& sgn1
!= sgn2
)
2061 || (code
== MINUS_EXPR
&& sgn1
== sgn2
))
2062 && is_overflow_infinity (val1
)
2063 && is_overflow_infinity (val2
))
2066 /* Don't try to handle division or shifting of infinities. */
2067 if ((code
== TRUNC_DIV_EXPR
2068 || code
== FLOOR_DIV_EXPR
2069 || code
== CEIL_DIV_EXPR
2070 || code
== EXACT_DIV_EXPR
2071 || code
== ROUND_DIV_EXPR
2072 || code
== RSHIFT_EXPR
)
2073 && (is_overflow_infinity (val1
)
2074 || is_overflow_infinity (val2
)))
2077 /* Notice that we only need to handle the restricted set of
2078 operations handled by extract_range_from_binary_expr.
2079 Among them, only multiplication, addition and subtraction
2080 can yield overflow without overflown operands because we
2081 are working with integral types only... except in the
2082 case VAL1 = -INF and VAL2 = -1 which overflows to +INF
2083 for division too. */
2085 /* For multiplication, the sign of the overflow is given
2086 by the comparison of the signs of the operands. */
2087 if ((code
== MULT_EXPR
&& sgn1
== sgn2
)
2088 /* For addition, the operands must be of the same sign
2089 to yield an overflow. Its sign is therefore that
2090 of one of the operands, for example the first. For
2091 infinite operands X + -INF is negative, not positive. */
2092 || (code
== PLUS_EXPR
2094 ? !is_negative_overflow_infinity (val2
)
2095 : is_positive_overflow_infinity (val2
)))
2096 /* For subtraction, non-infinite operands must be of
2097 different signs to yield an overflow. Its sign is
2098 therefore that of the first operand or the opposite of
2099 that of the second operand. A first operand of 0 counts
2100 as positive here, for the corner case 0 - (-INF), which
2101 overflows, but must yield +INF. For infinite operands 0
2102 - INF is negative, not positive. */
2103 || (code
== MINUS_EXPR
2105 ? !is_positive_overflow_infinity (val2
)
2106 : is_negative_overflow_infinity (val2
)))
2107 /* We only get in here with positive shift count, so the
2108 overflow direction is the same as the sign of val1.
2109 Actually rshift does not overflow at all, but we only
2110 handle the case of shifting overflowed -INF and +INF. */
2111 || (code
== RSHIFT_EXPR
2113 /* For division, the only case is -INF / -1 = +INF. */
2114 || code
== TRUNC_DIV_EXPR
2115 || code
== FLOOR_DIV_EXPR
2116 || code
== CEIL_DIV_EXPR
2117 || code
== EXACT_DIV_EXPR
2118 || code
== ROUND_DIV_EXPR
)
2119 return (needs_overflow_infinity (TREE_TYPE (res
))
2120 ? positive_overflow_infinity (TREE_TYPE (res
))
2121 : TYPE_MAX_VALUE (TREE_TYPE (res
)));
2123 return (needs_overflow_infinity (TREE_TYPE (res
))
2124 ? negative_overflow_infinity (TREE_TYPE (res
))
2125 : TYPE_MIN_VALUE (TREE_TYPE (res
)));
2132 /* For range VR compute two double_int bitmasks. In *MAY_BE_NONZERO
2133 bitmask if some bit is unset, it means for all numbers in the range
2134 the bit is 0, otherwise it might be 0 or 1. In *MUST_BE_NONZERO
2135 bitmask if some bit is set, it means for all numbers in the range
2136 the bit is 1, otherwise it might be 0 or 1. */
2139 zero_nonzero_bits_from_vr (value_range_t
*vr
,
2140 double_int
*may_be_nonzero
,
2141 double_int
*must_be_nonzero
)
2143 *may_be_nonzero
= double_int_minus_one
;
2144 *must_be_nonzero
= double_int_zero
;
2145 if (!range_int_cst_p (vr
))
2148 if (range_int_cst_singleton_p (vr
))
2150 *may_be_nonzero
= tree_to_double_int (vr
->min
);
2151 *must_be_nonzero
= *may_be_nonzero
;
2153 else if (tree_int_cst_sgn (vr
->min
) >= 0
2154 || tree_int_cst_sgn (vr
->max
) < 0)
2156 double_int dmin
= tree_to_double_int (vr
->min
);
2157 double_int dmax
= tree_to_double_int (vr
->max
);
2158 double_int xor_mask
= double_int_xor (dmin
, dmax
);
2159 *may_be_nonzero
= double_int_ior (dmin
, dmax
);
2160 *must_be_nonzero
= double_int_and (dmin
, dmax
);
2161 if (xor_mask
.high
!= 0)
2163 unsigned HOST_WIDE_INT mask
2164 = ((unsigned HOST_WIDE_INT
) 1
2165 << floor_log2 (xor_mask
.high
)) - 1;
2166 may_be_nonzero
->low
= ALL_ONES
;
2167 may_be_nonzero
->high
|= mask
;
2168 must_be_nonzero
->low
= 0;
2169 must_be_nonzero
->high
&= ~mask
;
2171 else if (xor_mask
.low
!= 0)
2173 unsigned HOST_WIDE_INT mask
2174 = ((unsigned HOST_WIDE_INT
) 1
2175 << floor_log2 (xor_mask
.low
)) - 1;
2176 may_be_nonzero
->low
|= mask
;
2177 must_be_nonzero
->low
&= ~mask
;
2185 /* Extract range information from a binary operation CODE based on
2186 the ranges of each of its operands, *VR0 and *VR1 with resulting
2187 type EXPR_TYPE. The resulting range is stored in *VR. */
2190 extract_range_from_binary_expr_1 (value_range_t
*vr
,
2191 enum tree_code code
, tree expr_type
,
2192 value_range_t
*vr0_
, value_range_t
*vr1_
)
2194 value_range_t vr0
= *vr0_
, vr1
= *vr1_
;
2195 enum value_range_type type
;
2199 /* Not all binary expressions can be applied to ranges in a
2200 meaningful way. Handle only arithmetic operations. */
2201 if (code
!= PLUS_EXPR
2202 && code
!= MINUS_EXPR
2203 && code
!= POINTER_PLUS_EXPR
2204 && code
!= MULT_EXPR
2205 && code
!= TRUNC_DIV_EXPR
2206 && code
!= FLOOR_DIV_EXPR
2207 && code
!= CEIL_DIV_EXPR
2208 && code
!= EXACT_DIV_EXPR
2209 && code
!= ROUND_DIV_EXPR
2210 && code
!= TRUNC_MOD_EXPR
2211 && code
!= RSHIFT_EXPR
2214 && code
!= BIT_AND_EXPR
2215 && code
!= BIT_IOR_EXPR
2216 && code
!= BIT_XOR_EXPR
)
2218 set_value_range_to_varying (vr
);
2222 /* If both ranges are UNDEFINED, so is the result. */
2223 if (vr0
.type
== VR_UNDEFINED
&& vr1
.type
== VR_UNDEFINED
)
2225 set_value_range_to_undefined (vr
);
2228 /* If one of the ranges is UNDEFINED drop it to VARYING for the following
2229 code. At some point we may want to special-case operations that
2230 have UNDEFINED result for all or some value-ranges of the not UNDEFINED
2232 else if (vr0
.type
== VR_UNDEFINED
)
2233 set_value_range_to_varying (&vr0
);
2234 else if (vr1
.type
== VR_UNDEFINED
)
2235 set_value_range_to_varying (&vr1
);
2237 /* The type of the resulting value range defaults to VR0.TYPE. */
2240 /* Refuse to operate on VARYING ranges, ranges of different kinds
2241 and symbolic ranges. As an exception, we allow BIT_AND_EXPR
2242 because we may be able to derive a useful range even if one of
2243 the operands is VR_VARYING or symbolic range. Similarly for
2244 divisions. TODO, we may be able to derive anti-ranges in
2246 if (code
!= BIT_AND_EXPR
2247 && code
!= BIT_IOR_EXPR
2248 && code
!= TRUNC_DIV_EXPR
2249 && code
!= FLOOR_DIV_EXPR
2250 && code
!= CEIL_DIV_EXPR
2251 && code
!= EXACT_DIV_EXPR
2252 && code
!= ROUND_DIV_EXPR
2253 && code
!= TRUNC_MOD_EXPR
2254 && (vr0
.type
== VR_VARYING
2255 || vr1
.type
== VR_VARYING
2256 || vr0
.type
!= vr1
.type
2257 || symbolic_range_p (&vr0
)
2258 || symbolic_range_p (&vr1
)))
2260 set_value_range_to_varying (vr
);
2264 /* Now evaluate the expression to determine the new range. */
2265 if (POINTER_TYPE_P (expr_type
))
2267 if (code
== MIN_EXPR
|| code
== MAX_EXPR
)
2269 /* For MIN/MAX expressions with pointers, we only care about
2270 nullness, if both are non null, then the result is nonnull.
2271 If both are null, then the result is null. Otherwise they
2273 if (range_is_nonnull (&vr0
) && range_is_nonnull (&vr1
))
2274 set_value_range_to_nonnull (vr
, expr_type
);
2275 else if (range_is_null (&vr0
) && range_is_null (&vr1
))
2276 set_value_range_to_null (vr
, expr_type
);
2278 set_value_range_to_varying (vr
);
2280 else if (code
== POINTER_PLUS_EXPR
)
2282 /* For pointer types, we are really only interested in asserting
2283 whether the expression evaluates to non-NULL. */
2284 if (range_is_nonnull (&vr0
) || range_is_nonnull (&vr1
))
2285 set_value_range_to_nonnull (vr
, expr_type
);
2286 else if (range_is_null (&vr0
) && range_is_null (&vr1
))
2287 set_value_range_to_null (vr
, expr_type
);
2289 set_value_range_to_varying (vr
);
2291 else if (code
== BIT_AND_EXPR
)
2293 /* For pointer types, we are really only interested in asserting
2294 whether the expression evaluates to non-NULL. */
2295 if (range_is_nonnull (&vr0
) && range_is_nonnull (&vr1
))
2296 set_value_range_to_nonnull (vr
, expr_type
);
2297 else if (range_is_null (&vr0
) || range_is_null (&vr1
))
2298 set_value_range_to_null (vr
, expr_type
);
2300 set_value_range_to_varying (vr
);
2303 set_value_range_to_varying (vr
);
2308 /* For integer ranges, apply the operation to each end of the
2309 range and see what we end up with. */
2310 if (code
== PLUS_EXPR
2312 || code
== MAX_EXPR
)
2314 /* If we have a PLUS_EXPR with two VR_ANTI_RANGEs, drop to
2315 VR_VARYING. It would take more effort to compute a precise
2316 range for such a case. For example, if we have op0 == 1 and
2317 op1 == -1 with their ranges both being ~[0,0], we would have
2318 op0 + op1 == 0, so we cannot claim that the sum is in ~[0,0].
2319 Note that we are guaranteed to have vr0.type == vr1.type at
2321 if (vr0
.type
== VR_ANTI_RANGE
)
2323 if (code
== PLUS_EXPR
)
2325 set_value_range_to_varying (vr
);
2328 /* For MIN_EXPR and MAX_EXPR with two VR_ANTI_RANGEs,
2329 the resulting VR_ANTI_RANGE is the same - intersection
2330 of the two ranges. */
2331 min
= vrp_int_const_binop (MAX_EXPR
, vr0
.min
, vr1
.min
);
2332 max
= vrp_int_const_binop (MIN_EXPR
, vr0
.max
, vr1
.max
);
2336 /* For operations that make the resulting range directly
2337 proportional to the original ranges, apply the operation to
2338 the same end of each range. */
2339 min
= vrp_int_const_binop (code
, vr0
.min
, vr1
.min
);
2340 max
= vrp_int_const_binop (code
, vr0
.max
, vr1
.max
);
2343 /* If both additions overflowed the range kind is still correct.
2344 This happens regularly with subtracting something in unsigned
2346 ??? See PR30318 for all the cases we do not handle. */
2347 if (code
== PLUS_EXPR
2348 && (TREE_OVERFLOW (min
) && !is_overflow_infinity (min
))
2349 && (TREE_OVERFLOW (max
) && !is_overflow_infinity (max
)))
2351 min
= build_int_cst_wide (TREE_TYPE (min
),
2352 TREE_INT_CST_LOW (min
),
2353 TREE_INT_CST_HIGH (min
));
2354 max
= build_int_cst_wide (TREE_TYPE (max
),
2355 TREE_INT_CST_LOW (max
),
2356 TREE_INT_CST_HIGH (max
));
2359 else if (code
== MULT_EXPR
2360 || code
== TRUNC_DIV_EXPR
2361 || code
== FLOOR_DIV_EXPR
2362 || code
== CEIL_DIV_EXPR
2363 || code
== EXACT_DIV_EXPR
2364 || code
== ROUND_DIV_EXPR
2365 || code
== RSHIFT_EXPR
)
2371 /* If we have an unsigned MULT_EXPR with two VR_ANTI_RANGEs,
2372 drop to VR_VARYING. It would take more effort to compute a
2373 precise range for such a case. For example, if we have
2374 op0 == 65536 and op1 == 65536 with their ranges both being
2375 ~[0,0] on a 32-bit machine, we would have op0 * op1 == 0, so
2376 we cannot claim that the product is in ~[0,0]. Note that we
2377 are guaranteed to have vr0.type == vr1.type at this
2379 if (code
== MULT_EXPR
2380 && vr0
.type
== VR_ANTI_RANGE
2381 && !TYPE_OVERFLOW_UNDEFINED (expr_type
))
2383 set_value_range_to_varying (vr
);
2387 /* If we have a RSHIFT_EXPR with any shift values outside [0..prec-1],
2388 then drop to VR_VARYING. Outside of this range we get undefined
2389 behavior from the shift operation. We cannot even trust
2390 SHIFT_COUNT_TRUNCATED at this stage, because that applies to rtl
2391 shifts, and the operation at the tree level may be widened. */
2392 if (code
== RSHIFT_EXPR
)
2394 if (vr1
.type
!= VR_RANGE
2395 || !value_range_nonnegative_p (&vr1
)
2396 || TREE_CODE (vr1
.max
) != INTEGER_CST
2397 || compare_tree_int (vr1
.max
,
2398 TYPE_PRECISION (expr_type
) - 1) == 1)
2400 set_value_range_to_varying (vr
);
2405 else if ((code
== TRUNC_DIV_EXPR
2406 || code
== FLOOR_DIV_EXPR
2407 || code
== CEIL_DIV_EXPR
2408 || code
== EXACT_DIV_EXPR
2409 || code
== ROUND_DIV_EXPR
)
2410 && (vr0
.type
!= VR_RANGE
|| symbolic_range_p (&vr0
)))
2412 /* For division, if op1 has VR_RANGE but op0 does not, something
2413 can be deduced just from that range. Say [min, max] / [4, max]
2414 gives [min / 4, max / 4] range. */
2415 if (vr1
.type
== VR_RANGE
2416 && !symbolic_range_p (&vr1
)
2417 && !range_includes_zero_p (&vr1
))
2419 vr0
.type
= type
= VR_RANGE
;
2420 vr0
.min
= vrp_val_min (expr_type
);
2421 vr0
.max
= vrp_val_max (expr_type
);
2425 set_value_range_to_varying (vr
);
2430 /* For divisions, if flag_non_call_exceptions is true, we must
2431 not eliminate a division by zero. */
2432 if ((code
== TRUNC_DIV_EXPR
2433 || code
== FLOOR_DIV_EXPR
2434 || code
== CEIL_DIV_EXPR
2435 || code
== EXACT_DIV_EXPR
2436 || code
== ROUND_DIV_EXPR
)
2437 && cfun
->can_throw_non_call_exceptions
2438 && (vr1
.type
!= VR_RANGE
2439 || symbolic_range_p (&vr1
)
2440 || range_includes_zero_p (&vr1
)))
2442 set_value_range_to_varying (vr
);
2446 /* For divisions, if op0 is VR_RANGE, we can deduce a range
2447 even if op1 is VR_VARYING, VR_ANTI_RANGE, symbolic or can
2449 if ((code
== TRUNC_DIV_EXPR
2450 || code
== FLOOR_DIV_EXPR
2451 || code
== CEIL_DIV_EXPR
2452 || code
== EXACT_DIV_EXPR
2453 || code
== ROUND_DIV_EXPR
)
2454 && vr0
.type
== VR_RANGE
2455 && (vr1
.type
!= VR_RANGE
2456 || symbolic_range_p (&vr1
)
2457 || range_includes_zero_p (&vr1
)))
2459 tree zero
= build_int_cst (TREE_TYPE (vr0
.min
), 0);
2465 if (TYPE_UNSIGNED (expr_type
)
2466 || value_range_nonnegative_p (&vr1
))
2468 /* For unsigned division or when divisor is known
2469 to be non-negative, the range has to cover
2470 all numbers from 0 to max for positive max
2471 and all numbers from min to 0 for negative min. */
2472 cmp
= compare_values (vr0
.max
, zero
);
2475 else if (cmp
== 0 || cmp
== 1)
2479 cmp
= compare_values (vr0
.min
, zero
);
2482 else if (cmp
== 0 || cmp
== -1)
2489 /* Otherwise the range is -max .. max or min .. -min
2490 depending on which bound is bigger in absolute value,
2491 as the division can change the sign. */
2492 abs_extent_range (vr
, vr0
.min
, vr0
.max
);
2495 if (type
== VR_VARYING
)
2497 set_value_range_to_varying (vr
);
2502 /* Multiplications and divisions are a bit tricky to handle,
2503 depending on the mix of signs we have in the two ranges, we
2504 need to operate on different values to get the minimum and
2505 maximum values for the new range. One approach is to figure
2506 out all the variations of range combinations and do the
2509 However, this involves several calls to compare_values and it
2510 is pretty convoluted. It's simpler to do the 4 operations
2511 (MIN0 OP MIN1, MIN0 OP MAX1, MAX0 OP MIN1 and MAX0 OP MAX0 OP
2512 MAX1) and then figure the smallest and largest values to form
2516 gcc_assert ((vr0
.type
== VR_RANGE
2517 || (code
== MULT_EXPR
&& vr0
.type
== VR_ANTI_RANGE
))
2518 && vr0
.type
== vr1
.type
);
2520 /* Compute the 4 cross operations. */
2522 val
[0] = vrp_int_const_binop (code
, vr0
.min
, vr1
.min
);
2523 if (val
[0] == NULL_TREE
)
2526 if (vr1
.max
== vr1
.min
)
2530 val
[1] = vrp_int_const_binop (code
, vr0
.min
, vr1
.max
);
2531 if (val
[1] == NULL_TREE
)
2535 if (vr0
.max
== vr0
.min
)
2539 val
[2] = vrp_int_const_binop (code
, vr0
.max
, vr1
.min
);
2540 if (val
[2] == NULL_TREE
)
2544 if (vr0
.min
== vr0
.max
|| vr1
.min
== vr1
.max
)
2548 val
[3] = vrp_int_const_binop (code
, vr0
.max
, vr1
.max
);
2549 if (val
[3] == NULL_TREE
)
2555 set_value_range_to_varying (vr
);
2559 /* Set MIN to the minimum of VAL[i] and MAX to the maximum
2563 for (i
= 1; i
< 4; i
++)
2565 if (!is_gimple_min_invariant (min
)
2566 || (TREE_OVERFLOW (min
) && !is_overflow_infinity (min
))
2567 || !is_gimple_min_invariant (max
)
2568 || (TREE_OVERFLOW (max
) && !is_overflow_infinity (max
)))
2573 if (!is_gimple_min_invariant (val
[i
])
2574 || (TREE_OVERFLOW (val
[i
])
2575 && !is_overflow_infinity (val
[i
])))
2577 /* If we found an overflowed value, set MIN and MAX
2578 to it so that we set the resulting range to
2584 if (compare_values (val
[i
], min
) == -1)
2587 if (compare_values (val
[i
], max
) == 1)
2593 else if (code
== TRUNC_MOD_EXPR
)
2595 if (vr1
.type
!= VR_RANGE
2596 || symbolic_range_p (&vr1
)
2597 || range_includes_zero_p (&vr1
)
2598 || vrp_val_is_min (vr1
.min
))
2600 set_value_range_to_varying (vr
);
2604 /* Compute MAX <|vr1.min|, |vr1.max|> - 1. */
2605 max
= fold_unary_to_constant (ABS_EXPR
, expr_type
, vr1
.min
);
2606 if (tree_int_cst_lt (max
, vr1
.max
))
2608 max
= int_const_binop (MINUS_EXPR
, max
, integer_one_node
);
2609 /* If the dividend is non-negative the modulus will be
2610 non-negative as well. */
2611 if (TYPE_UNSIGNED (expr_type
)
2612 || value_range_nonnegative_p (&vr0
))
2613 min
= build_int_cst (TREE_TYPE (max
), 0);
2615 min
= fold_unary_to_constant (NEGATE_EXPR
, expr_type
, max
);
2617 else if (code
== MINUS_EXPR
)
2619 /* If we have a MINUS_EXPR with two VR_ANTI_RANGEs, drop to
2620 VR_VARYING. It would take more effort to compute a precise
2621 range for such a case. For example, if we have op0 == 1 and
2622 op1 == 1 with their ranges both being ~[0,0], we would have
2623 op0 - op1 == 0, so we cannot claim that the difference is in
2624 ~[0,0]. Note that we are guaranteed to have
2625 vr0.type == vr1.type at this point. */
2626 if (vr0
.type
== VR_ANTI_RANGE
)
2628 set_value_range_to_varying (vr
);
2632 /* For MINUS_EXPR, apply the operation to the opposite ends of
2634 min
= vrp_int_const_binop (code
, vr0
.min
, vr1
.max
);
2635 max
= vrp_int_const_binop (code
, vr0
.max
, vr1
.min
);
2637 else if (code
== BIT_AND_EXPR
|| code
== BIT_IOR_EXPR
|| code
== BIT_XOR_EXPR
)
2639 bool int_cst_range0
, int_cst_range1
;
2640 double_int may_be_nonzero0
, may_be_nonzero1
;
2641 double_int must_be_nonzero0
, must_be_nonzero1
;
2643 int_cst_range0
= zero_nonzero_bits_from_vr (&vr0
, &may_be_nonzero0
,
2645 int_cst_range1
= zero_nonzero_bits_from_vr (&vr1
, &may_be_nonzero1
,
2649 if (code
== BIT_AND_EXPR
)
2652 min
= double_int_to_tree (expr_type
,
2653 double_int_and (must_be_nonzero0
,
2655 dmax
= double_int_and (may_be_nonzero0
, may_be_nonzero1
);
2656 /* If both input ranges contain only negative values we can
2657 truncate the result range maximum to the minimum of the
2658 input range maxima. */
2659 if (int_cst_range0
&& int_cst_range1
2660 && tree_int_cst_sgn (vr0
.max
) < 0
2661 && tree_int_cst_sgn (vr1
.max
) < 0)
2663 dmax
= double_int_min (dmax
, tree_to_double_int (vr0
.max
),
2664 TYPE_UNSIGNED (expr_type
));
2665 dmax
= double_int_min (dmax
, tree_to_double_int (vr1
.max
),
2666 TYPE_UNSIGNED (expr_type
));
2668 /* If either input range contains only non-negative values
2669 we can truncate the result range maximum to the respective
2670 maximum of the input range. */
2671 if (int_cst_range0
&& tree_int_cst_sgn (vr0
.min
) >= 0)
2672 dmax
= double_int_min (dmax
, tree_to_double_int (vr0
.max
),
2673 TYPE_UNSIGNED (expr_type
));
2674 if (int_cst_range1
&& tree_int_cst_sgn (vr1
.min
) >= 0)
2675 dmax
= double_int_min (dmax
, tree_to_double_int (vr1
.max
),
2676 TYPE_UNSIGNED (expr_type
));
2677 max
= double_int_to_tree (expr_type
, dmax
);
2679 else if (code
== BIT_IOR_EXPR
)
2682 max
= double_int_to_tree (expr_type
,
2683 double_int_ior (may_be_nonzero0
,
2685 dmin
= double_int_ior (must_be_nonzero0
, must_be_nonzero1
);
2686 /* If the input ranges contain only positive values we can
2687 truncate the minimum of the result range to the maximum
2688 of the input range minima. */
2689 if (int_cst_range0
&& int_cst_range1
2690 && tree_int_cst_sgn (vr0
.min
) >= 0
2691 && tree_int_cst_sgn (vr1
.min
) >= 0)
2693 dmin
= double_int_max (dmin
, tree_to_double_int (vr0
.min
),
2694 TYPE_UNSIGNED (expr_type
));
2695 dmin
= double_int_max (dmin
, tree_to_double_int (vr1
.min
),
2696 TYPE_UNSIGNED (expr_type
));
2698 /* If either input range contains only negative values
2699 we can truncate the minimum of the result range to the
2700 respective minimum range. */
2701 if (int_cst_range0
&& tree_int_cst_sgn (vr0
.max
) < 0)
2702 dmin
= double_int_max (dmin
, tree_to_double_int (vr0
.min
),
2703 TYPE_UNSIGNED (expr_type
));
2704 if (int_cst_range1
&& tree_int_cst_sgn (vr1
.max
) < 0)
2705 dmin
= double_int_max (dmin
, tree_to_double_int (vr1
.min
),
2706 TYPE_UNSIGNED (expr_type
));
2707 min
= double_int_to_tree (expr_type
, dmin
);
2709 else if (code
== BIT_XOR_EXPR
)
2711 double_int result_zero_bits
, result_one_bits
;
2713 = double_int_ior (double_int_and (must_be_nonzero0
,
2716 (double_int_ior (may_be_nonzero0
,
2719 = double_int_ior (double_int_and
2721 double_int_not (may_be_nonzero1
)),
2724 double_int_not (may_be_nonzero0
)));
2725 max
= double_int_to_tree (expr_type
,
2726 double_int_not (result_zero_bits
));
2727 min
= double_int_to_tree (expr_type
, result_one_bits
);
2728 /* If the range has all positive or all negative values the
2729 result is better than VARYING. */
2730 if (tree_int_cst_sgn (min
) < 0
2731 || tree_int_cst_sgn (max
) >= 0)
2734 max
= min
= NULL_TREE
;
2738 set_value_range_to_varying (vr
);
2745 /* If either MIN or MAX overflowed, then set the resulting range to
2746 VARYING. But we do accept an overflow infinity
2748 if (min
== NULL_TREE
2749 || !is_gimple_min_invariant (min
)
2750 || (TREE_OVERFLOW (min
) && !is_overflow_infinity (min
))
2752 || !is_gimple_min_invariant (max
)
2753 || (TREE_OVERFLOW (max
) && !is_overflow_infinity (max
)))
2755 set_value_range_to_varying (vr
);
2761 2) [-INF, +-INF(OVF)]
2762 3) [+-INF(OVF), +INF]
2763 4) [+-INF(OVF), +-INF(OVF)]
2764 We learn nothing when we have INF and INF(OVF) on both sides.
2765 Note that we do accept [-INF, -INF] and [+INF, +INF] without
2767 if ((vrp_val_is_min (min
) || is_overflow_infinity (min
))
2768 && (vrp_val_is_max (max
) || is_overflow_infinity (max
)))
2770 set_value_range_to_varying (vr
);
2774 cmp
= compare_values (min
, max
);
2775 if (cmp
== -2 || cmp
== 1)
2777 /* If the new range has its limits swapped around (MIN > MAX),
2778 then the operation caused one of them to wrap around, mark
2779 the new range VARYING. */
2780 set_value_range_to_varying (vr
);
2783 set_value_range (vr
, type
, min
, max
, NULL
);
2786 /* Extract range information from a binary expression OP0 CODE OP1 based on
2787 the ranges of each of its operands with resulting type EXPR_TYPE.
2788 The resulting range is stored in *VR. */
2791 extract_range_from_binary_expr (value_range_t
*vr
,
2792 enum tree_code code
,
2793 tree expr_type
, tree op0
, tree op1
)
2795 value_range_t vr0
= { VR_UNDEFINED
, NULL_TREE
, NULL_TREE
, NULL
};
2796 value_range_t vr1
= { VR_UNDEFINED
, NULL_TREE
, NULL_TREE
, NULL
};
2798 /* Get value ranges for each operand. For constant operands, create
2799 a new value range with the operand to simplify processing. */
2800 if (TREE_CODE (op0
) == SSA_NAME
)
2801 vr0
= *(get_value_range (op0
));
2802 else if (is_gimple_min_invariant (op0
))
2803 set_value_range_to_value (&vr0
, op0
, NULL
);
2805 set_value_range_to_varying (&vr0
);
2807 if (TREE_CODE (op1
) == SSA_NAME
)
2808 vr1
= *(get_value_range (op1
));
2809 else if (is_gimple_min_invariant (op1
))
2810 set_value_range_to_value (&vr1
, op1
, NULL
);
2812 set_value_range_to_varying (&vr1
);
2814 extract_range_from_binary_expr_1 (vr
, code
, expr_type
, &vr0
, &vr1
);
2817 /* Extract range information from a unary operation CODE based on
2818 the range of its operand *VR0 with type OP0_TYPE with resulting type TYPE.
2819 The The resulting range is stored in *VR. */
2822 extract_range_from_unary_expr_1 (value_range_t
*vr
,
2823 enum tree_code code
, tree type
,
2824 value_range_t
*vr0_
, tree op0_type
)
2826 value_range_t vr0
= *vr0_
;
2828 /* VRP only operates on integral and pointer types. */
2829 if (!(INTEGRAL_TYPE_P (op0_type
)
2830 || POINTER_TYPE_P (op0_type
))
2831 || !(INTEGRAL_TYPE_P (type
)
2832 || POINTER_TYPE_P (type
)))
2834 set_value_range_to_varying (vr
);
2838 /* If VR0 is UNDEFINED, so is the result. */
2839 if (vr0
.type
== VR_UNDEFINED
)
2841 set_value_range_to_undefined (vr
);
2845 if (CONVERT_EXPR_CODE_P (code
))
2847 tree inner_type
= op0_type
;
2848 tree outer_type
= type
;
2850 /* If the expression evaluates to a pointer, we are only interested in
2851 determining if it evaluates to NULL [0, 0] or non-NULL (~[0, 0]). */
2852 if (POINTER_TYPE_P (type
))
2854 if (CONVERT_EXPR_CODE_P (code
))
2856 if (range_is_nonnull (&vr0
))
2857 set_value_range_to_nonnull (vr
, type
);
2858 else if (range_is_null (&vr0
))
2859 set_value_range_to_null (vr
, type
);
2861 set_value_range_to_varying (vr
);
2864 set_value_range_to_varying (vr
);
2868 /* If VR0 is varying and we increase the type precision, assume
2869 a full range for the following transformation. */
2870 if (vr0
.type
== VR_VARYING
2871 && INTEGRAL_TYPE_P (inner_type
)
2872 && TYPE_PRECISION (inner_type
) < TYPE_PRECISION (outer_type
))
2874 vr0
.type
= VR_RANGE
;
2875 vr0
.min
= TYPE_MIN_VALUE (inner_type
);
2876 vr0
.max
= TYPE_MAX_VALUE (inner_type
);
2879 /* If VR0 is a constant range or anti-range and the conversion is
2880 not truncating we can convert the min and max values and
2881 canonicalize the resulting range. Otherwise we can do the
2882 conversion if the size of the range is less than what the
2883 precision of the target type can represent and the range is
2884 not an anti-range. */
2885 if ((vr0
.type
== VR_RANGE
2886 || vr0
.type
== VR_ANTI_RANGE
)
2887 && TREE_CODE (vr0
.min
) == INTEGER_CST
2888 && TREE_CODE (vr0
.max
) == INTEGER_CST
2889 && (!is_overflow_infinity (vr0
.min
)
2890 || (vr0
.type
== VR_RANGE
2891 && TYPE_PRECISION (outer_type
) > TYPE_PRECISION (inner_type
)
2892 && needs_overflow_infinity (outer_type
)
2893 && supports_overflow_infinity (outer_type
)))
2894 && (!is_overflow_infinity (vr0
.max
)
2895 || (vr0
.type
== VR_RANGE
2896 && TYPE_PRECISION (outer_type
) > TYPE_PRECISION (inner_type
)
2897 && needs_overflow_infinity (outer_type
)
2898 && supports_overflow_infinity (outer_type
)))
2899 && (TYPE_PRECISION (outer_type
) >= TYPE_PRECISION (inner_type
)
2900 || (vr0
.type
== VR_RANGE
2901 && integer_zerop (int_const_binop (RSHIFT_EXPR
,
2902 int_const_binop (MINUS_EXPR
, vr0
.max
, vr0
.min
),
2903 size_int (TYPE_PRECISION (outer_type
)))))))
2905 tree new_min
, new_max
;
2906 new_min
= force_fit_type_double (outer_type
,
2907 tree_to_double_int (vr0
.min
),
2909 new_max
= force_fit_type_double (outer_type
,
2910 tree_to_double_int (vr0
.max
),
2912 if (is_overflow_infinity (vr0
.min
))
2913 new_min
= negative_overflow_infinity (outer_type
);
2914 if (is_overflow_infinity (vr0
.max
))
2915 new_max
= positive_overflow_infinity (outer_type
);
2916 set_and_canonicalize_value_range (vr
, vr0
.type
,
2917 new_min
, new_max
, NULL
);
2921 set_value_range_to_varying (vr
);
2924 else if (code
== NEGATE_EXPR
)
2926 /* -X is simply 0 - X, so re-use existing code that also handles
2927 anti-ranges fine. */
2928 value_range_t zero
= { VR_UNDEFINED
, NULL_TREE
, NULL_TREE
, NULL
};
2929 set_value_range_to_value (&zero
, build_int_cst (type
, 0), NULL
);
2930 extract_range_from_binary_expr_1 (vr
, MINUS_EXPR
, type
, &zero
, &vr0
);
2933 else if (code
== ABS_EXPR
)
2938 /* Pass through vr0 in the easy cases. */
2939 if (TYPE_UNSIGNED (type
)
2940 || value_range_nonnegative_p (&vr0
))
2942 copy_value_range (vr
, &vr0
);
2946 /* For the remaining varying or symbolic ranges we can't do anything
2948 if (vr0
.type
== VR_VARYING
2949 || symbolic_range_p (&vr0
))
2951 set_value_range_to_varying (vr
);
2955 /* -TYPE_MIN_VALUE = TYPE_MIN_VALUE with flag_wrapv so we can't get a
2957 if (!TYPE_OVERFLOW_UNDEFINED (type
)
2958 && ((vr0
.type
== VR_RANGE
2959 && vrp_val_is_min (vr0
.min
))
2960 || (vr0
.type
== VR_ANTI_RANGE
2961 && !vrp_val_is_min (vr0
.min
))))
2963 set_value_range_to_varying (vr
);
2967 /* ABS_EXPR may flip the range around, if the original range
2968 included negative values. */
2969 if (is_overflow_infinity (vr0
.min
))
2970 min
= positive_overflow_infinity (type
);
2971 else if (!vrp_val_is_min (vr0
.min
))
2972 min
= fold_unary_to_constant (code
, type
, vr0
.min
);
2973 else if (!needs_overflow_infinity (type
))
2974 min
= TYPE_MAX_VALUE (type
);
2975 else if (supports_overflow_infinity (type
))
2976 min
= positive_overflow_infinity (type
);
2979 set_value_range_to_varying (vr
);
2983 if (is_overflow_infinity (vr0
.max
))
2984 max
= positive_overflow_infinity (type
);
2985 else if (!vrp_val_is_min (vr0
.max
))
2986 max
= fold_unary_to_constant (code
, type
, vr0
.max
);
2987 else if (!needs_overflow_infinity (type
))
2988 max
= TYPE_MAX_VALUE (type
);
2989 else if (supports_overflow_infinity (type
)
2990 /* We shouldn't generate [+INF, +INF] as set_value_range
2991 doesn't like this and ICEs. */
2992 && !is_positive_overflow_infinity (min
))
2993 max
= positive_overflow_infinity (type
);
2996 set_value_range_to_varying (vr
);
3000 cmp
= compare_values (min
, max
);
3002 /* If a VR_ANTI_RANGEs contains zero, then we have
3003 ~[-INF, min(MIN, MAX)]. */
3004 if (vr0
.type
== VR_ANTI_RANGE
)
3006 if (range_includes_zero_p (&vr0
))
3008 /* Take the lower of the two values. */
3012 /* Create ~[-INF, min (abs(MIN), abs(MAX))]
3013 or ~[-INF + 1, min (abs(MIN), abs(MAX))] when
3014 flag_wrapv is set and the original anti-range doesn't include
3015 TYPE_MIN_VALUE, remember -TYPE_MIN_VALUE = TYPE_MIN_VALUE. */
3016 if (TYPE_OVERFLOW_WRAPS (type
))
3018 tree type_min_value
= TYPE_MIN_VALUE (type
);
3020 min
= (vr0
.min
!= type_min_value
3021 ? int_const_binop (PLUS_EXPR
, type_min_value
,
3027 if (overflow_infinity_range_p (&vr0
))
3028 min
= negative_overflow_infinity (type
);
3030 min
= TYPE_MIN_VALUE (type
);
3035 /* All else has failed, so create the range [0, INF], even for
3036 flag_wrapv since TYPE_MIN_VALUE is in the original
3038 vr0
.type
= VR_RANGE
;
3039 min
= build_int_cst (type
, 0);
3040 if (needs_overflow_infinity (type
))
3042 if (supports_overflow_infinity (type
))
3043 max
= positive_overflow_infinity (type
);
3046 set_value_range_to_varying (vr
);
3051 max
= TYPE_MAX_VALUE (type
);
3055 /* If the range contains zero then we know that the minimum value in the
3056 range will be zero. */
3057 else if (range_includes_zero_p (&vr0
))
3061 min
= build_int_cst (type
, 0);
3065 /* If the range was reversed, swap MIN and MAX. */
3074 cmp
= compare_values (min
, max
);
3075 if (cmp
== -2 || cmp
== 1)
3077 /* If the new range has its limits swapped around (MIN > MAX),
3078 then the operation caused one of them to wrap around, mark
3079 the new range VARYING. */
3080 set_value_range_to_varying (vr
);
3083 set_value_range (vr
, vr0
.type
, min
, max
, NULL
);
3086 else if (code
== BIT_NOT_EXPR
)
3088 /* ~X is simply -1 - X, so re-use existing code that also handles
3089 anti-ranges fine. */
3090 value_range_t minusone
= { VR_UNDEFINED
, NULL_TREE
, NULL_TREE
, NULL
};
3091 set_value_range_to_value (&minusone
, build_int_cst (type
, -1), NULL
);
3092 extract_range_from_binary_expr_1 (vr
, MINUS_EXPR
,
3093 type
, &minusone
, &vr0
);
3096 else if (code
== PAREN_EXPR
)
3098 copy_value_range (vr
, &vr0
);
3102 /* For unhandled operations fall back to varying. */
3103 set_value_range_to_varying (vr
);
3108 /* Extract range information from a unary expression CODE OP0 based on
3109 the range of its operand with resulting type TYPE.
3110 The resulting range is stored in *VR. */
3113 extract_range_from_unary_expr (value_range_t
*vr
, enum tree_code code
,
3114 tree type
, tree op0
)
3116 value_range_t vr0
= { VR_UNDEFINED
, NULL_TREE
, NULL_TREE
, NULL
};
3118 /* Get value ranges for the operand. For constant operands, create
3119 a new value range with the operand to simplify processing. */
3120 if (TREE_CODE (op0
) == SSA_NAME
)
3121 vr0
= *(get_value_range (op0
));
3122 else if (is_gimple_min_invariant (op0
))
3123 set_value_range_to_value (&vr0
, op0
, NULL
);
3125 set_value_range_to_varying (&vr0
);
3127 extract_range_from_unary_expr_1 (vr
, code
, type
, &vr0
, TREE_TYPE (op0
));
3131 /* Extract range information from a conditional expression EXPR based on
3132 the ranges of each of its operands and the expression code. */
3135 extract_range_from_cond_expr (value_range_t
*vr
, tree expr
)
3138 value_range_t vr0
= { VR_UNDEFINED
, NULL_TREE
, NULL_TREE
, NULL
};
3139 value_range_t vr1
= { VR_UNDEFINED
, NULL_TREE
, NULL_TREE
, NULL
};
3141 /* Get value ranges for each operand. For constant operands, create
3142 a new value range with the operand to simplify processing. */
3143 op0
= COND_EXPR_THEN (expr
);
3144 if (TREE_CODE (op0
) == SSA_NAME
)
3145 vr0
= *(get_value_range (op0
));
3146 else if (is_gimple_min_invariant (op0
))
3147 set_value_range_to_value (&vr0
, op0
, NULL
);
3149 set_value_range_to_varying (&vr0
);
3151 op1
= COND_EXPR_ELSE (expr
);
3152 if (TREE_CODE (op1
) == SSA_NAME
)
3153 vr1
= *(get_value_range (op1
));
3154 else if (is_gimple_min_invariant (op1
))
3155 set_value_range_to_value (&vr1
, op1
, NULL
);
3157 set_value_range_to_varying (&vr1
);
3159 /* The resulting value range is the union of the operand ranges */
3160 vrp_meet (&vr0
, &vr1
);
3161 copy_value_range (vr
, &vr0
);
3165 /* Extract range information from a comparison expression EXPR based
3166 on the range of its operand and the expression code. */
3169 extract_range_from_comparison (value_range_t
*vr
, enum tree_code code
,
3170 tree type
, tree op0
, tree op1
)
3175 val
= vrp_evaluate_conditional_warnv_with_ops (code
, op0
, op1
, false, &sop
,
3178 /* A disadvantage of using a special infinity as an overflow
3179 representation is that we lose the ability to record overflow
3180 when we don't have an infinity. So we have to ignore a result
3181 which relies on overflow. */
3183 if (val
&& !is_overflow_infinity (val
) && !sop
)
3185 /* Since this expression was found on the RHS of an assignment,
3186 its type may be different from _Bool. Convert VAL to EXPR's
3188 val
= fold_convert (type
, val
);
3189 if (is_gimple_min_invariant (val
))
3190 set_value_range_to_value (vr
, val
, vr
->equiv
);
3192 set_value_range (vr
, VR_RANGE
, val
, val
, vr
->equiv
);
3195 /* The result of a comparison is always true or false. */
3196 set_value_range_to_truthvalue (vr
, type
);
3199 /* Try to derive a nonnegative or nonzero range out of STMT relying
3200 primarily on generic routines in fold in conjunction with range data.
3201 Store the result in *VR */
3204 extract_range_basic (value_range_t
*vr
, gimple stmt
)
3207 tree type
= gimple_expr_type (stmt
);
3209 if (INTEGRAL_TYPE_P (type
)
3210 && gimple_stmt_nonnegative_warnv_p (stmt
, &sop
))
3211 set_value_range_to_nonnegative (vr
, type
,
3212 sop
|| stmt_overflow_infinity (stmt
));
3213 else if (vrp_stmt_computes_nonzero (stmt
, &sop
)
3215 set_value_range_to_nonnull (vr
, type
);
3217 set_value_range_to_varying (vr
);
3221 /* Try to compute a useful range out of assignment STMT and store it
3225 extract_range_from_assignment (value_range_t
*vr
, gimple stmt
)
3227 enum tree_code code
= gimple_assign_rhs_code (stmt
);
3229 if (code
== ASSERT_EXPR
)
3230 extract_range_from_assert (vr
, gimple_assign_rhs1 (stmt
));
3231 else if (code
== SSA_NAME
)
3232 extract_range_from_ssa_name (vr
, gimple_assign_rhs1 (stmt
));
3233 else if (TREE_CODE_CLASS (code
) == tcc_binary
)
3234 extract_range_from_binary_expr (vr
, gimple_assign_rhs_code (stmt
),
3235 gimple_expr_type (stmt
),
3236 gimple_assign_rhs1 (stmt
),
3237 gimple_assign_rhs2 (stmt
));
3238 else if (TREE_CODE_CLASS (code
) == tcc_unary
)
3239 extract_range_from_unary_expr (vr
, gimple_assign_rhs_code (stmt
),
3240 gimple_expr_type (stmt
),
3241 gimple_assign_rhs1 (stmt
));
3242 else if (code
== COND_EXPR
)
3243 extract_range_from_cond_expr (vr
, gimple_assign_rhs1 (stmt
));
3244 else if (TREE_CODE_CLASS (code
) == tcc_comparison
)
3245 extract_range_from_comparison (vr
, gimple_assign_rhs_code (stmt
),
3246 gimple_expr_type (stmt
),
3247 gimple_assign_rhs1 (stmt
),
3248 gimple_assign_rhs2 (stmt
));
3249 else if (get_gimple_rhs_class (code
) == GIMPLE_SINGLE_RHS
3250 && is_gimple_min_invariant (gimple_assign_rhs1 (stmt
)))
3251 set_value_range_to_value (vr
, gimple_assign_rhs1 (stmt
), NULL
);
3253 set_value_range_to_varying (vr
);
3255 if (vr
->type
== VR_VARYING
)
3256 extract_range_basic (vr
, stmt
);
3259 /* Given a range VR, a LOOP and a variable VAR, determine whether it
3260 would be profitable to adjust VR using scalar evolution information
3261 for VAR. If so, update VR with the new limits. */
3264 adjust_range_with_scev (value_range_t
*vr
, struct loop
*loop
,
3265 gimple stmt
, tree var
)
3267 tree init
, step
, chrec
, tmin
, tmax
, min
, max
, type
, tem
;
3268 enum ev_direction dir
;
3270 /* TODO. Don't adjust anti-ranges. An anti-range may provide
3271 better opportunities than a regular range, but I'm not sure. */
3272 if (vr
->type
== VR_ANTI_RANGE
)
3275 chrec
= instantiate_parameters (loop
, analyze_scalar_evolution (loop
, var
));
3277 /* Like in PR19590, scev can return a constant function. */
3278 if (is_gimple_min_invariant (chrec
))
3280 set_value_range_to_value (vr
, chrec
, vr
->equiv
);
3284 if (TREE_CODE (chrec
) != POLYNOMIAL_CHREC
)
3287 init
= initial_condition_in_loop_num (chrec
, loop
->num
);
3288 tem
= op_with_constant_singleton_value_range (init
);
3291 step
= evolution_part_in_loop_num (chrec
, loop
->num
);
3292 tem
= op_with_constant_singleton_value_range (step
);
3296 /* If STEP is symbolic, we can't know whether INIT will be the
3297 minimum or maximum value in the range. Also, unless INIT is
3298 a simple expression, compare_values and possibly other functions
3299 in tree-vrp won't be able to handle it. */
3300 if (step
== NULL_TREE
3301 || !is_gimple_min_invariant (step
)
3302 || !valid_value_p (init
))
3305 dir
= scev_direction (chrec
);
3306 if (/* Do not adjust ranges if we do not know whether the iv increases
3307 or decreases, ... */
3308 dir
== EV_DIR_UNKNOWN
3309 /* ... or if it may wrap. */
3310 || scev_probably_wraps_p (init
, step
, stmt
, get_chrec_loop (chrec
),
3314 /* We use TYPE_MIN_VALUE and TYPE_MAX_VALUE here instead of
3315 negative_overflow_infinity and positive_overflow_infinity,
3316 because we have concluded that the loop probably does not
3319 type
= TREE_TYPE (var
);
3320 if (POINTER_TYPE_P (type
) || !TYPE_MIN_VALUE (type
))
3321 tmin
= lower_bound_in_type (type
, type
);
3323 tmin
= TYPE_MIN_VALUE (type
);
3324 if (POINTER_TYPE_P (type
) || !TYPE_MAX_VALUE (type
))
3325 tmax
= upper_bound_in_type (type
, type
);
3327 tmax
= TYPE_MAX_VALUE (type
);
3329 /* Try to use estimated number of iterations for the loop to constrain the
3330 final value in the evolution. */
3331 if (TREE_CODE (step
) == INTEGER_CST
3332 && is_gimple_val (init
)
3333 && (TREE_CODE (init
) != SSA_NAME
3334 || get_value_range (init
)->type
== VR_RANGE
))
3338 if (estimated_loop_iterations (loop
, true, &nit
))
3340 value_range_t maxvr
= { VR_UNDEFINED
, NULL_TREE
, NULL_TREE
, NULL
};
3342 bool unsigned_p
= TYPE_UNSIGNED (TREE_TYPE (step
));
3345 dtmp
= double_int_mul_with_sign (tree_to_double_int (step
), nit
,
3346 unsigned_p
, &overflow
);
3347 /* If the multiplication overflowed we can't do a meaningful
3348 adjustment. Likewise if the result doesn't fit in the type
3349 of the induction variable. For a signed type we have to
3350 check whether the result has the expected signedness which
3351 is that of the step as number of iterations is unsigned. */
3353 && double_int_fits_to_tree_p (TREE_TYPE (init
), dtmp
)
3355 || ((dtmp
.high
^ TREE_INT_CST_HIGH (step
)) >= 0)))
3357 tem
= double_int_to_tree (TREE_TYPE (init
), dtmp
);
3358 extract_range_from_binary_expr (&maxvr
, PLUS_EXPR
,
3359 TREE_TYPE (init
), init
, tem
);
3360 /* Likewise if the addition did. */
3361 if (maxvr
.type
== VR_RANGE
)
3370 if (vr
->type
== VR_VARYING
|| vr
->type
== VR_UNDEFINED
)
3375 /* For VARYING or UNDEFINED ranges, just about anything we get
3376 from scalar evolutions should be better. */
3378 if (dir
== EV_DIR_DECREASES
)
3383 /* If we would create an invalid range, then just assume we
3384 know absolutely nothing. This may be over-conservative,
3385 but it's clearly safe, and should happen only in unreachable
3386 parts of code, or for invalid programs. */
3387 if (compare_values (min
, max
) == 1)
3390 set_value_range (vr
, VR_RANGE
, min
, max
, vr
->equiv
);
3392 else if (vr
->type
== VR_RANGE
)
3397 if (dir
== EV_DIR_DECREASES
)
3399 /* INIT is the maximum value. If INIT is lower than VR->MAX
3400 but no smaller than VR->MIN, set VR->MAX to INIT. */
3401 if (compare_values (init
, max
) == -1)
3404 /* According to the loop information, the variable does not
3405 overflow. If we think it does, probably because of an
3406 overflow due to arithmetic on a different INF value,
3408 if (is_negative_overflow_infinity (min
)
3409 || compare_values (min
, tmin
) == -1)
3415 /* If INIT is bigger than VR->MIN, set VR->MIN to INIT. */
3416 if (compare_values (init
, min
) == 1)
3419 if (is_positive_overflow_infinity (max
)
3420 || compare_values (tmax
, max
) == -1)
3424 /* If we just created an invalid range with the minimum
3425 greater than the maximum, we fail conservatively.
3426 This should happen only in unreachable
3427 parts of code, or for invalid programs. */
3428 if (compare_values (min
, max
) == 1)
3431 set_value_range (vr
, VR_RANGE
, min
, max
, vr
->equiv
);
3435 /* Return true if VAR may overflow at STMT. This checks any available
3436 loop information to see if we can determine that VAR does not
3440 vrp_var_may_overflow (tree var
, gimple stmt
)
3443 tree chrec
, init
, step
;
3445 if (current_loops
== NULL
)
3448 l
= loop_containing_stmt (stmt
);
3453 chrec
= instantiate_parameters (l
, analyze_scalar_evolution (l
, var
));
3454 if (TREE_CODE (chrec
) != POLYNOMIAL_CHREC
)
3457 init
= initial_condition_in_loop_num (chrec
, l
->num
);
3458 step
= evolution_part_in_loop_num (chrec
, l
->num
);
3460 if (step
== NULL_TREE
3461 || !is_gimple_min_invariant (step
)
3462 || !valid_value_p (init
))
3465 /* If we get here, we know something useful about VAR based on the
3466 loop information. If it wraps, it may overflow. */
3468 if (scev_probably_wraps_p (init
, step
, stmt
, get_chrec_loop (chrec
),
3472 if (dump_file
&& (dump_flags
& TDF_DETAILS
) != 0)
3474 print_generic_expr (dump_file
, var
, 0);
3475 fprintf (dump_file
, ": loop information indicates does not overflow\n");
3482 /* Given two numeric value ranges VR0, VR1 and a comparison code COMP:
3484 - Return BOOLEAN_TRUE_NODE if VR0 COMP VR1 always returns true for
3485 all the values in the ranges.
3487 - Return BOOLEAN_FALSE_NODE if the comparison always returns false.
3489 - Return NULL_TREE if it is not always possible to determine the
3490 value of the comparison.
3492 Also set *STRICT_OVERFLOW_P to indicate whether a range with an
3493 overflow infinity was used in the test. */
3497 compare_ranges (enum tree_code comp
, value_range_t
*vr0
, value_range_t
*vr1
,
3498 bool *strict_overflow_p
)
3500 /* VARYING or UNDEFINED ranges cannot be compared. */
3501 if (vr0
->type
== VR_VARYING
3502 || vr0
->type
== VR_UNDEFINED
3503 || vr1
->type
== VR_VARYING
3504 || vr1
->type
== VR_UNDEFINED
)
3507 /* Anti-ranges need to be handled separately. */
3508 if (vr0
->type
== VR_ANTI_RANGE
|| vr1
->type
== VR_ANTI_RANGE
)
3510 /* If both are anti-ranges, then we cannot compute any
3512 if (vr0
->type
== VR_ANTI_RANGE
&& vr1
->type
== VR_ANTI_RANGE
)
3515 /* These comparisons are never statically computable. */
3522 /* Equality can be computed only between a range and an
3523 anti-range. ~[VAL1, VAL2] == [VAL1, VAL2] is always false. */
3524 if (vr0
->type
== VR_RANGE
)
3526 /* To simplify processing, make VR0 the anti-range. */
3527 value_range_t
*tmp
= vr0
;
3532 gcc_assert (comp
== NE_EXPR
|| comp
== EQ_EXPR
);
3534 if (compare_values_warnv (vr0
->min
, vr1
->min
, strict_overflow_p
) == 0
3535 && compare_values_warnv (vr0
->max
, vr1
->max
, strict_overflow_p
) == 0)
3536 return (comp
== NE_EXPR
) ? boolean_true_node
: boolean_false_node
;
3541 if (!usable_range_p (vr0
, strict_overflow_p
)
3542 || !usable_range_p (vr1
, strict_overflow_p
))
3545 /* Simplify processing. If COMP is GT_EXPR or GE_EXPR, switch the
3546 operands around and change the comparison code. */
3547 if (comp
== GT_EXPR
|| comp
== GE_EXPR
)
3550 comp
= (comp
== GT_EXPR
) ? LT_EXPR
: LE_EXPR
;
3556 if (comp
== EQ_EXPR
)
3558 /* Equality may only be computed if both ranges represent
3559 exactly one value. */
3560 if (compare_values_warnv (vr0
->min
, vr0
->max
, strict_overflow_p
) == 0
3561 && compare_values_warnv (vr1
->min
, vr1
->max
, strict_overflow_p
) == 0)
3563 int cmp_min
= compare_values_warnv (vr0
->min
, vr1
->min
,
3565 int cmp_max
= compare_values_warnv (vr0
->max
, vr1
->max
,
3567 if (cmp_min
== 0 && cmp_max
== 0)
3568 return boolean_true_node
;
3569 else if (cmp_min
!= -2 && cmp_max
!= -2)
3570 return boolean_false_node
;
3572 /* If [V0_MIN, V1_MAX] < [V1_MIN, V1_MAX] then V0 != V1. */
3573 else if (compare_values_warnv (vr0
->min
, vr1
->max
,
3574 strict_overflow_p
) == 1
3575 || compare_values_warnv (vr1
->min
, vr0
->max
,
3576 strict_overflow_p
) == 1)
3577 return boolean_false_node
;
3581 else if (comp
== NE_EXPR
)
3585 /* If VR0 is completely to the left or completely to the right
3586 of VR1, they are always different. Notice that we need to
3587 make sure that both comparisons yield similar results to
3588 avoid comparing values that cannot be compared at
3590 cmp1
= compare_values_warnv (vr0
->max
, vr1
->min
, strict_overflow_p
);
3591 cmp2
= compare_values_warnv (vr0
->min
, vr1
->max
, strict_overflow_p
);
3592 if ((cmp1
== -1 && cmp2
== -1) || (cmp1
== 1 && cmp2
== 1))
3593 return boolean_true_node
;
3595 /* If VR0 and VR1 represent a single value and are identical,
3597 else if (compare_values_warnv (vr0
->min
, vr0
->max
,
3598 strict_overflow_p
) == 0
3599 && compare_values_warnv (vr1
->min
, vr1
->max
,
3600 strict_overflow_p
) == 0
3601 && compare_values_warnv (vr0
->min
, vr1
->min
,
3602 strict_overflow_p
) == 0
3603 && compare_values_warnv (vr0
->max
, vr1
->max
,
3604 strict_overflow_p
) == 0)
3605 return boolean_false_node
;
3607 /* Otherwise, they may or may not be different. */
3611 else if (comp
== LT_EXPR
|| comp
== LE_EXPR
)
3615 /* If VR0 is to the left of VR1, return true. */
3616 tst
= compare_values_warnv (vr0
->max
, vr1
->min
, strict_overflow_p
);
3617 if ((comp
== LT_EXPR
&& tst
== -1)
3618 || (comp
== LE_EXPR
&& (tst
== -1 || tst
== 0)))
3620 if (overflow_infinity_range_p (vr0
)
3621 || overflow_infinity_range_p (vr1
))
3622 *strict_overflow_p
= true;
3623 return boolean_true_node
;
3626 /* If VR0 is to the right of VR1, return false. */
3627 tst
= compare_values_warnv (vr0
->min
, vr1
->max
, strict_overflow_p
);
3628 if ((comp
== LT_EXPR
&& (tst
== 0 || tst
== 1))
3629 || (comp
== LE_EXPR
&& tst
== 1))
3631 if (overflow_infinity_range_p (vr0
)
3632 || overflow_infinity_range_p (vr1
))
3633 *strict_overflow_p
= true;
3634 return boolean_false_node
;
3637 /* Otherwise, we don't know. */
3645 /* Given a value range VR, a value VAL and a comparison code COMP, return
3646 BOOLEAN_TRUE_NODE if VR COMP VAL always returns true for all the
3647 values in VR. Return BOOLEAN_FALSE_NODE if the comparison
3648 always returns false. Return NULL_TREE if it is not always
3649 possible to determine the value of the comparison. Also set
3650 *STRICT_OVERFLOW_P to indicate whether a range with an overflow
3651 infinity was used in the test. */
3654 compare_range_with_value (enum tree_code comp
, value_range_t
*vr
, tree val
,
3655 bool *strict_overflow_p
)
3657 if (vr
->type
== VR_VARYING
|| vr
->type
== VR_UNDEFINED
)
3660 /* Anti-ranges need to be handled separately. */
3661 if (vr
->type
== VR_ANTI_RANGE
)
3663 /* For anti-ranges, the only predicates that we can compute at
3664 compile time are equality and inequality. */
3671 /* ~[VAL_1, VAL_2] OP VAL is known if VAL_1 <= VAL <= VAL_2. */
3672 if (value_inside_range (val
, vr
) == 1)
3673 return (comp
== NE_EXPR
) ? boolean_true_node
: boolean_false_node
;
3678 if (!usable_range_p (vr
, strict_overflow_p
))
3681 if (comp
== EQ_EXPR
)
3683 /* EQ_EXPR may only be computed if VR represents exactly
3685 if (compare_values_warnv (vr
->min
, vr
->max
, strict_overflow_p
) == 0)
3687 int cmp
= compare_values_warnv (vr
->min
, val
, strict_overflow_p
);
3689 return boolean_true_node
;
3690 else if (cmp
== -1 || cmp
== 1 || cmp
== 2)
3691 return boolean_false_node
;
3693 else if (compare_values_warnv (val
, vr
->min
, strict_overflow_p
) == -1
3694 || compare_values_warnv (vr
->max
, val
, strict_overflow_p
) == -1)
3695 return boolean_false_node
;
3699 else if (comp
== NE_EXPR
)
3701 /* If VAL is not inside VR, then they are always different. */
3702 if (compare_values_warnv (vr
->max
, val
, strict_overflow_p
) == -1
3703 || compare_values_warnv (vr
->min
, val
, strict_overflow_p
) == 1)
3704 return boolean_true_node
;
3706 /* If VR represents exactly one value equal to VAL, then return
3708 if (compare_values_warnv (vr
->min
, vr
->max
, strict_overflow_p
) == 0
3709 && compare_values_warnv (vr
->min
, val
, strict_overflow_p
) == 0)
3710 return boolean_false_node
;
3712 /* Otherwise, they may or may not be different. */
3715 else if (comp
== LT_EXPR
|| comp
== LE_EXPR
)
3719 /* If VR is to the left of VAL, return true. */
3720 tst
= compare_values_warnv (vr
->max
, val
, strict_overflow_p
);
3721 if ((comp
== LT_EXPR
&& tst
== -1)
3722 || (comp
== LE_EXPR
&& (tst
== -1 || tst
== 0)))
3724 if (overflow_infinity_range_p (vr
))
3725 *strict_overflow_p
= true;
3726 return boolean_true_node
;
3729 /* If VR is to the right of VAL, return false. */
3730 tst
= compare_values_warnv (vr
->min
, val
, strict_overflow_p
);
3731 if ((comp
== LT_EXPR
&& (tst
== 0 || tst
== 1))
3732 || (comp
== LE_EXPR
&& tst
== 1))
3734 if (overflow_infinity_range_p (vr
))
3735 *strict_overflow_p
= true;
3736 return boolean_false_node
;
3739 /* Otherwise, we don't know. */
3742 else if (comp
== GT_EXPR
|| comp
== GE_EXPR
)
3746 /* If VR is to the right of VAL, return true. */
3747 tst
= compare_values_warnv (vr
->min
, val
, strict_overflow_p
);
3748 if ((comp
== GT_EXPR
&& tst
== 1)
3749 || (comp
== GE_EXPR
&& (tst
== 0 || tst
== 1)))
3751 if (overflow_infinity_range_p (vr
))
3752 *strict_overflow_p
= true;
3753 return boolean_true_node
;
3756 /* If VR is to the left of VAL, return false. */
3757 tst
= compare_values_warnv (vr
->max
, val
, strict_overflow_p
);
3758 if ((comp
== GT_EXPR
&& (tst
== -1 || tst
== 0))
3759 || (comp
== GE_EXPR
&& tst
== -1))
3761 if (overflow_infinity_range_p (vr
))
3762 *strict_overflow_p
= true;
3763 return boolean_false_node
;
3766 /* Otherwise, we don't know. */
3774 /* Debugging dumps. */
3776 void dump_value_range (FILE *, value_range_t
*);
3777 void debug_value_range (value_range_t
*);
3778 void dump_all_value_ranges (FILE *);
3779 void debug_all_value_ranges (void);
3780 void dump_vr_equiv (FILE *, bitmap
);
3781 void debug_vr_equiv (bitmap
);
3784 /* Dump value range VR to FILE. */
3787 dump_value_range (FILE *file
, value_range_t
*vr
)
3790 fprintf (file
, "[]");
3791 else if (vr
->type
== VR_UNDEFINED
)
3792 fprintf (file
, "UNDEFINED");
3793 else if (vr
->type
== VR_RANGE
|| vr
->type
== VR_ANTI_RANGE
)
3795 tree type
= TREE_TYPE (vr
->min
);
3797 fprintf (file
, "%s[", (vr
->type
== VR_ANTI_RANGE
) ? "~" : "");
3799 if (is_negative_overflow_infinity (vr
->min
))
3800 fprintf (file
, "-INF(OVF)");
3801 else if (INTEGRAL_TYPE_P (type
)
3802 && !TYPE_UNSIGNED (type
)
3803 && vrp_val_is_min (vr
->min
))
3804 fprintf (file
, "-INF");
3806 print_generic_expr (file
, vr
->min
, 0);
3808 fprintf (file
, ", ");
3810 if (is_positive_overflow_infinity (vr
->max
))
3811 fprintf (file
, "+INF(OVF)");
3812 else if (INTEGRAL_TYPE_P (type
)
3813 && vrp_val_is_max (vr
->max
))
3814 fprintf (file
, "+INF");
3816 print_generic_expr (file
, vr
->max
, 0);
3818 fprintf (file
, "]");
3825 fprintf (file
, " EQUIVALENCES: { ");
3827 EXECUTE_IF_SET_IN_BITMAP (vr
->equiv
, 0, i
, bi
)
3829 print_generic_expr (file
, ssa_name (i
), 0);
3830 fprintf (file
, " ");
3834 fprintf (file
, "} (%u elements)", c
);
3837 else if (vr
->type
== VR_VARYING
)
3838 fprintf (file
, "VARYING");
3840 fprintf (file
, "INVALID RANGE");
3844 /* Dump value range VR to stderr. */
3847 debug_value_range (value_range_t
*vr
)
3849 dump_value_range (stderr
, vr
);
3850 fprintf (stderr
, "\n");
3854 /* Dump value ranges of all SSA_NAMEs to FILE. */
3857 dump_all_value_ranges (FILE *file
)
3861 for (i
= 0; i
< num_vr_values
; i
++)
3865 print_generic_expr (file
, ssa_name (i
), 0);
3866 fprintf (file
, ": ");
3867 dump_value_range (file
, vr_value
[i
]);
3868 fprintf (file
, "\n");
3872 fprintf (file
, "\n");
3876 /* Dump all value ranges to stderr. */
3879 debug_all_value_ranges (void)
3881 dump_all_value_ranges (stderr
);
3885 /* Given a COND_EXPR COND of the form 'V OP W', and an SSA name V,
3886 create a new SSA name N and return the assertion assignment
3887 'V = ASSERT_EXPR <V, V OP W>'. */
3890 build_assert_expr_for (tree cond
, tree v
)
3895 gcc_assert (TREE_CODE (v
) == SSA_NAME
);
3896 n
= duplicate_ssa_name (v
, NULL
);
3898 if (COMPARISON_CLASS_P (cond
))
3900 tree a
= build2 (ASSERT_EXPR
, TREE_TYPE (v
), v
, cond
);
3901 assertion
= gimple_build_assign (n
, a
);
3903 else if (TREE_CODE (cond
) == SSA_NAME
)
3905 /* Given V, build the assignment N = true. */
3906 gcc_assert (v
== cond
);
3907 assertion
= gimple_build_assign (n
, boolean_true_node
);
3912 SSA_NAME_DEF_STMT (n
) = assertion
;
3914 /* The new ASSERT_EXPR, creates a new SSA name that replaces the
3915 operand of the ASSERT_EXPR. Register the new name and the old one
3916 in the replacement table so that we can fix the SSA web after
3917 adding all the ASSERT_EXPRs. */
3918 register_new_name_mapping (n
, v
);
3924 /* Return false if EXPR is a predicate expression involving floating
3928 fp_predicate (gimple stmt
)
3930 GIMPLE_CHECK (stmt
, GIMPLE_COND
);
3932 return FLOAT_TYPE_P (TREE_TYPE (gimple_cond_lhs (stmt
)));
3936 /* If the range of values taken by OP can be inferred after STMT executes,
3937 return the comparison code (COMP_CODE_P) and value (VAL_P) that
3938 describes the inferred range. Return true if a range could be
3942 infer_value_range (gimple stmt
, tree op
, enum tree_code
*comp_code_p
, tree
*val_p
)
3945 *comp_code_p
= ERROR_MARK
;
3947 /* Do not attempt to infer anything in names that flow through
3949 if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (op
))
3952 /* Similarly, don't infer anything from statements that may throw
3954 if (stmt_could_throw_p (stmt
))
3957 /* If STMT is the last statement of a basic block with no
3958 successors, there is no point inferring anything about any of its
3959 operands. We would not be able to find a proper insertion point
3960 for the assertion, anyway. */
3961 if (stmt_ends_bb_p (stmt
) && EDGE_COUNT (gimple_bb (stmt
)->succs
) == 0)
3964 /* We can only assume that a pointer dereference will yield
3965 non-NULL if -fdelete-null-pointer-checks is enabled. */
3966 if (flag_delete_null_pointer_checks
3967 && POINTER_TYPE_P (TREE_TYPE (op
))
3968 && gimple_code (stmt
) != GIMPLE_ASM
)
3970 unsigned num_uses
, num_loads
, num_stores
;
3972 count_uses_and_derefs (op
, stmt
, &num_uses
, &num_loads
, &num_stores
);
3973 if (num_loads
+ num_stores
> 0)
3975 *val_p
= build_int_cst (TREE_TYPE (op
), 0);
3976 *comp_code_p
= NE_EXPR
;
3985 void dump_asserts_for (FILE *, tree
);
3986 void debug_asserts_for (tree
);
3987 void dump_all_asserts (FILE *);
3988 void debug_all_asserts (void);
3990 /* Dump all the registered assertions for NAME to FILE. */
3993 dump_asserts_for (FILE *file
, tree name
)
3997 fprintf (file
, "Assertions to be inserted for ");
3998 print_generic_expr (file
, name
, 0);
3999 fprintf (file
, "\n");
4001 loc
= asserts_for
[SSA_NAME_VERSION (name
)];
4004 fprintf (file
, "\t");
4005 print_gimple_stmt (file
, gsi_stmt (loc
->si
), 0, 0);
4006 fprintf (file
, "\n\tBB #%d", loc
->bb
->index
);
4009 fprintf (file
, "\n\tEDGE %d->%d", loc
->e
->src
->index
,
4010 loc
->e
->dest
->index
);
4011 dump_edge_info (file
, loc
->e
, 0);
4013 fprintf (file
, "\n\tPREDICATE: ");
4014 print_generic_expr (file
, name
, 0);
4015 fprintf (file
, " %s ", tree_code_name
[(int)loc
->comp_code
]);
4016 print_generic_expr (file
, loc
->val
, 0);
4017 fprintf (file
, "\n\n");
4021 fprintf (file
, "\n");
4025 /* Dump all the registered assertions for NAME to stderr. */
4028 debug_asserts_for (tree name
)
4030 dump_asserts_for (stderr
, name
);
4034 /* Dump all the registered assertions for all the names to FILE. */
4037 dump_all_asserts (FILE *file
)
4042 fprintf (file
, "\nASSERT_EXPRs to be inserted\n\n");
4043 EXECUTE_IF_SET_IN_BITMAP (need_assert_for
, 0, i
, bi
)
4044 dump_asserts_for (file
, ssa_name (i
));
4045 fprintf (file
, "\n");
4049 /* Dump all the registered assertions for all the names to stderr. */
4052 debug_all_asserts (void)
4054 dump_all_asserts (stderr
);
4058 /* If NAME doesn't have an ASSERT_EXPR registered for asserting
4059 'EXPR COMP_CODE VAL' at a location that dominates block BB or
4060 E->DEST, then register this location as a possible insertion point
4061 for ASSERT_EXPR <NAME, EXPR COMP_CODE VAL>.
4063 BB, E and SI provide the exact insertion point for the new
4064 ASSERT_EXPR. If BB is NULL, then the ASSERT_EXPR is to be inserted
4065 on edge E. Otherwise, if E is NULL, the ASSERT_EXPR is inserted on
4066 BB. If SI points to a COND_EXPR or a SWITCH_EXPR statement, then E
4067 must not be NULL. */
4070 register_new_assert_for (tree name
, tree expr
,
4071 enum tree_code comp_code
,
4075 gimple_stmt_iterator si
)
4077 assert_locus_t n
, loc
, last_loc
;
4078 basic_block dest_bb
;
4080 gcc_checking_assert (bb
== NULL
|| e
== NULL
);
4083 gcc_checking_assert (gimple_code (gsi_stmt (si
)) != GIMPLE_COND
4084 && gimple_code (gsi_stmt (si
)) != GIMPLE_SWITCH
);
4086 /* Never build an assert comparing against an integer constant with
4087 TREE_OVERFLOW set. This confuses our undefined overflow warning
4089 if (TREE_CODE (val
) == INTEGER_CST
4090 && TREE_OVERFLOW (val
))
4091 val
= build_int_cst_wide (TREE_TYPE (val
),
4092 TREE_INT_CST_LOW (val
), TREE_INT_CST_HIGH (val
));
4094 /* The new assertion A will be inserted at BB or E. We need to
4095 determine if the new location is dominated by a previously
4096 registered location for A. If we are doing an edge insertion,
4097 assume that A will be inserted at E->DEST. Note that this is not
4100 If E is a critical edge, it will be split. But even if E is
4101 split, the new block will dominate the same set of blocks that
4104 The reverse, however, is not true, blocks dominated by E->DEST
4105 will not be dominated by the new block created to split E. So,
4106 if the insertion location is on a critical edge, we will not use
4107 the new location to move another assertion previously registered
4108 at a block dominated by E->DEST. */
4109 dest_bb
= (bb
) ? bb
: e
->dest
;
4111 /* If NAME already has an ASSERT_EXPR registered for COMP_CODE and
4112 VAL at a block dominating DEST_BB, then we don't need to insert a new
4113 one. Similarly, if the same assertion already exists at a block
4114 dominated by DEST_BB and the new location is not on a critical
4115 edge, then update the existing location for the assertion (i.e.,
4116 move the assertion up in the dominance tree).
4118 Note, this is implemented as a simple linked list because there
4119 should not be more than a handful of assertions registered per
4120 name. If this becomes a performance problem, a table hashed by
4121 COMP_CODE and VAL could be implemented. */
4122 loc
= asserts_for
[SSA_NAME_VERSION (name
)];
4126 if (loc
->comp_code
== comp_code
4128 || operand_equal_p (loc
->val
, val
, 0))
4129 && (loc
->expr
== expr
4130 || operand_equal_p (loc
->expr
, expr
, 0)))
4132 /* If the assertion NAME COMP_CODE VAL has already been
4133 registered at a basic block that dominates DEST_BB, then
4134 we don't need to insert the same assertion again. Note
4135 that we don't check strict dominance here to avoid
4136 replicating the same assertion inside the same basic
4137 block more than once (e.g., when a pointer is
4138 dereferenced several times inside a block).
4140 An exception to this rule are edge insertions. If the
4141 new assertion is to be inserted on edge E, then it will
4142 dominate all the other insertions that we may want to
4143 insert in DEST_BB. So, if we are doing an edge
4144 insertion, don't do this dominance check. */
4146 && dominated_by_p (CDI_DOMINATORS
, dest_bb
, loc
->bb
))
4149 /* Otherwise, if E is not a critical edge and DEST_BB
4150 dominates the existing location for the assertion, move
4151 the assertion up in the dominance tree by updating its
4152 location information. */
4153 if ((e
== NULL
|| !EDGE_CRITICAL_P (e
))
4154 && dominated_by_p (CDI_DOMINATORS
, loc
->bb
, dest_bb
))
4163 /* Update the last node of the list and move to the next one. */
4168 /* If we didn't find an assertion already registered for
4169 NAME COMP_CODE VAL, add a new one at the end of the list of
4170 assertions associated with NAME. */
4171 n
= XNEW (struct assert_locus_d
);
4175 n
->comp_code
= comp_code
;
4183 asserts_for
[SSA_NAME_VERSION (name
)] = n
;
4185 bitmap_set_bit (need_assert_for
, SSA_NAME_VERSION (name
));
4188 /* (COND_OP0 COND_CODE COND_OP1) is a predicate which uses NAME.
4189 Extract a suitable test code and value and store them into *CODE_P and
4190 *VAL_P so the predicate is normalized to NAME *CODE_P *VAL_P.
4192 If no extraction was possible, return FALSE, otherwise return TRUE.
4194 If INVERT is true, then we invert the result stored into *CODE_P. */
4197 extract_code_and_val_from_cond_with_ops (tree name
, enum tree_code cond_code
,
4198 tree cond_op0
, tree cond_op1
,
4199 bool invert
, enum tree_code
*code_p
,
4202 enum tree_code comp_code
;
4205 /* Otherwise, we have a comparison of the form NAME COMP VAL
4206 or VAL COMP NAME. */
4207 if (name
== cond_op1
)
4209 /* If the predicate is of the form VAL COMP NAME, flip
4210 COMP around because we need to register NAME as the
4211 first operand in the predicate. */
4212 comp_code
= swap_tree_comparison (cond_code
);
4217 /* The comparison is of the form NAME COMP VAL, so the
4218 comparison code remains unchanged. */
4219 comp_code
= cond_code
;
4223 /* Invert the comparison code as necessary. */
4225 comp_code
= invert_tree_comparison (comp_code
, 0);
4227 /* VRP does not handle float types. */
4228 if (SCALAR_FLOAT_TYPE_P (TREE_TYPE (val
)))
4231 /* Do not register always-false predicates.
4232 FIXME: this works around a limitation in fold() when dealing with
4233 enumerations. Given 'enum { N1, N2 } x;', fold will not
4234 fold 'if (x > N2)' to 'if (0)'. */
4235 if ((comp_code
== GT_EXPR
|| comp_code
== LT_EXPR
)
4236 && INTEGRAL_TYPE_P (TREE_TYPE (val
)))
4238 tree min
= TYPE_MIN_VALUE (TREE_TYPE (val
));
4239 tree max
= TYPE_MAX_VALUE (TREE_TYPE (val
));
4241 if (comp_code
== GT_EXPR
4243 || compare_values (val
, max
) == 0))
4246 if (comp_code
== LT_EXPR
4248 || compare_values (val
, min
) == 0))
4251 *code_p
= comp_code
;
4256 /* Try to register an edge assertion for SSA name NAME on edge E for
4257 the condition COND contributing to the conditional jump pointed to by BSI.
4258 Invert the condition COND if INVERT is true.
4259 Return true if an assertion for NAME could be registered. */
4262 register_edge_assert_for_2 (tree name
, edge e
, gimple_stmt_iterator bsi
,
4263 enum tree_code cond_code
,
4264 tree cond_op0
, tree cond_op1
, bool invert
)
4267 enum tree_code comp_code
;
4268 bool retval
= false;
4270 if (!extract_code_and_val_from_cond_with_ops (name
, cond_code
,
4273 invert
, &comp_code
, &val
))
4276 /* Only register an ASSERT_EXPR if NAME was found in the sub-graph
4277 reachable from E. */
4278 if (live_on_edge (e
, name
)
4279 && !has_single_use (name
))
4281 register_new_assert_for (name
, name
, comp_code
, val
, NULL
, e
, bsi
);
4285 /* In the case of NAME <= CST and NAME being defined as
4286 NAME = (unsigned) NAME2 + CST2 we can assert NAME2 >= -CST2
4287 and NAME2 <= CST - CST2. We can do the same for NAME > CST.
4288 This catches range and anti-range tests. */
4289 if ((comp_code
== LE_EXPR
4290 || comp_code
== GT_EXPR
)
4291 && TREE_CODE (val
) == INTEGER_CST
4292 && TYPE_UNSIGNED (TREE_TYPE (val
)))
4294 gimple def_stmt
= SSA_NAME_DEF_STMT (name
);
4295 tree cst2
= NULL_TREE
, name2
= NULL_TREE
, name3
= NULL_TREE
;
4297 /* Extract CST2 from the (optional) addition. */
4298 if (is_gimple_assign (def_stmt
)
4299 && gimple_assign_rhs_code (def_stmt
) == PLUS_EXPR
)
4301 name2
= gimple_assign_rhs1 (def_stmt
);
4302 cst2
= gimple_assign_rhs2 (def_stmt
);
4303 if (TREE_CODE (name2
) == SSA_NAME
4304 && TREE_CODE (cst2
) == INTEGER_CST
)
4305 def_stmt
= SSA_NAME_DEF_STMT (name2
);
4308 /* Extract NAME2 from the (optional) sign-changing cast. */
4309 if (gimple_assign_cast_p (def_stmt
))
4311 if (CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (def_stmt
))
4312 && ! TYPE_UNSIGNED (TREE_TYPE (gimple_assign_rhs1 (def_stmt
)))
4313 && (TYPE_PRECISION (gimple_expr_type (def_stmt
))
4314 == TYPE_PRECISION (TREE_TYPE (gimple_assign_rhs1 (def_stmt
)))))
4315 name3
= gimple_assign_rhs1 (def_stmt
);
4318 /* If name3 is used later, create an ASSERT_EXPR for it. */
4319 if (name3
!= NULL_TREE
4320 && TREE_CODE (name3
) == SSA_NAME
4321 && (cst2
== NULL_TREE
4322 || TREE_CODE (cst2
) == INTEGER_CST
)
4323 && INTEGRAL_TYPE_P (TREE_TYPE (name3
))
4324 && live_on_edge (e
, name3
)
4325 && !has_single_use (name3
))
4329 /* Build an expression for the range test. */
4330 tmp
= build1 (NOP_EXPR
, TREE_TYPE (name
), name3
);
4331 if (cst2
!= NULL_TREE
)
4332 tmp
= build2 (PLUS_EXPR
, TREE_TYPE (name
), tmp
, cst2
);
4336 fprintf (dump_file
, "Adding assert for ");
4337 print_generic_expr (dump_file
, name3
, 0);
4338 fprintf (dump_file
, " from ");
4339 print_generic_expr (dump_file
, tmp
, 0);
4340 fprintf (dump_file
, "\n");
4343 register_new_assert_for (name3
, tmp
, comp_code
, val
, NULL
, e
, bsi
);
4348 /* If name2 is used later, create an ASSERT_EXPR for it. */
4349 if (name2
!= NULL_TREE
4350 && TREE_CODE (name2
) == SSA_NAME
4351 && TREE_CODE (cst2
) == INTEGER_CST
4352 && INTEGRAL_TYPE_P (TREE_TYPE (name2
))
4353 && live_on_edge (e
, name2
)
4354 && !has_single_use (name2
))
4358 /* Build an expression for the range test. */
4360 if (TREE_TYPE (name
) != TREE_TYPE (name2
))
4361 tmp
= build1 (NOP_EXPR
, TREE_TYPE (name
), tmp
);
4362 if (cst2
!= NULL_TREE
)
4363 tmp
= build2 (PLUS_EXPR
, TREE_TYPE (name
), tmp
, cst2
);
4367 fprintf (dump_file
, "Adding assert for ");
4368 print_generic_expr (dump_file
, name2
, 0);
4369 fprintf (dump_file
, " from ");
4370 print_generic_expr (dump_file
, tmp
, 0);
4371 fprintf (dump_file
, "\n");
4374 register_new_assert_for (name2
, tmp
, comp_code
, val
, NULL
, e
, bsi
);
4383 /* OP is an operand of a truth value expression which is known to have
4384 a particular value. Register any asserts for OP and for any
4385 operands in OP's defining statement.
4387 If CODE is EQ_EXPR, then we want to register OP is zero (false),
4388 if CODE is NE_EXPR, then we want to register OP is nonzero (true). */
4391 register_edge_assert_for_1 (tree op
, enum tree_code code
,
4392 edge e
, gimple_stmt_iterator bsi
)
4394 bool retval
= false;
4397 enum tree_code rhs_code
;
4399 /* We only care about SSA_NAMEs. */
4400 if (TREE_CODE (op
) != SSA_NAME
)
4403 /* We know that OP will have a zero or nonzero value. If OP is used
4404 more than once go ahead and register an assert for OP.
4406 The FOUND_IN_SUBGRAPH support is not helpful in this situation as
4407 it will always be set for OP (because OP is used in a COND_EXPR in
4409 if (!has_single_use (op
))
4411 val
= build_int_cst (TREE_TYPE (op
), 0);
4412 register_new_assert_for (op
, op
, code
, val
, NULL
, e
, bsi
);
4416 /* Now look at how OP is set. If it's set from a comparison,
4417 a truth operation or some bit operations, then we may be able
4418 to register information about the operands of that assignment. */
4419 op_def
= SSA_NAME_DEF_STMT (op
);
4420 if (gimple_code (op_def
) != GIMPLE_ASSIGN
)
4423 rhs_code
= gimple_assign_rhs_code (op_def
);
4425 if (TREE_CODE_CLASS (rhs_code
) == tcc_comparison
)
4427 bool invert
= (code
== EQ_EXPR
? true : false);
4428 tree op0
= gimple_assign_rhs1 (op_def
);
4429 tree op1
= gimple_assign_rhs2 (op_def
);
4431 if (TREE_CODE (op0
) == SSA_NAME
)
4432 retval
|= register_edge_assert_for_2 (op0
, e
, bsi
, rhs_code
, op0
, op1
,
4434 if (TREE_CODE (op1
) == SSA_NAME
)
4435 retval
|= register_edge_assert_for_2 (op1
, e
, bsi
, rhs_code
, op0
, op1
,
4438 else if ((code
== NE_EXPR
4439 && gimple_assign_rhs_code (op_def
) == BIT_AND_EXPR
)
4441 && gimple_assign_rhs_code (op_def
) == BIT_IOR_EXPR
))
4443 /* Recurse on each operand. */
4444 retval
|= register_edge_assert_for_1 (gimple_assign_rhs1 (op_def
),
4446 retval
|= register_edge_assert_for_1 (gimple_assign_rhs2 (op_def
),
4449 else if (gimple_assign_rhs_code (op_def
) == BIT_NOT_EXPR
4450 && TYPE_PRECISION (TREE_TYPE (gimple_assign_lhs (op_def
))) == 1)
4452 /* Recurse, flipping CODE. */
4453 code
= invert_tree_comparison (code
, false);
4454 retval
|= register_edge_assert_for_1 (gimple_assign_rhs1 (op_def
),
4457 else if (gimple_assign_rhs_code (op_def
) == SSA_NAME
)
4459 /* Recurse through the copy. */
4460 retval
|= register_edge_assert_for_1 (gimple_assign_rhs1 (op_def
),
4463 else if (CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (op_def
)))
4465 /* Recurse through the type conversion. */
4466 retval
|= register_edge_assert_for_1 (gimple_assign_rhs1 (op_def
),
4473 /* Try to register an edge assertion for SSA name NAME on edge E for
4474 the condition COND contributing to the conditional jump pointed to by SI.
4475 Return true if an assertion for NAME could be registered. */
4478 register_edge_assert_for (tree name
, edge e
, gimple_stmt_iterator si
,
4479 enum tree_code cond_code
, tree cond_op0
,
4483 enum tree_code comp_code
;
4484 bool retval
= false;
4485 bool is_else_edge
= (e
->flags
& EDGE_FALSE_VALUE
) != 0;
4487 /* Do not attempt to infer anything in names that flow through
4489 if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (name
))
4492 if (!extract_code_and_val_from_cond_with_ops (name
, cond_code
,
4498 /* Register ASSERT_EXPRs for name. */
4499 retval
|= register_edge_assert_for_2 (name
, e
, si
, cond_code
, cond_op0
,
4500 cond_op1
, is_else_edge
);
4503 /* If COND is effectively an equality test of an SSA_NAME against
4504 the value zero or one, then we may be able to assert values
4505 for SSA_NAMEs which flow into COND. */
4507 /* In the case of NAME == 1 or NAME != 0, for BIT_AND_EXPR defining
4508 statement of NAME we can assert both operands of the BIT_AND_EXPR
4509 have nonzero value. */
4510 if (((comp_code
== EQ_EXPR
&& integer_onep (val
))
4511 || (comp_code
== NE_EXPR
&& integer_zerop (val
))))
4513 gimple def_stmt
= SSA_NAME_DEF_STMT (name
);
4515 if (is_gimple_assign (def_stmt
)
4516 && gimple_assign_rhs_code (def_stmt
) == BIT_AND_EXPR
)
4518 tree op0
= gimple_assign_rhs1 (def_stmt
);
4519 tree op1
= gimple_assign_rhs2 (def_stmt
);
4520 retval
|= register_edge_assert_for_1 (op0
, NE_EXPR
, e
, si
);
4521 retval
|= register_edge_assert_for_1 (op1
, NE_EXPR
, e
, si
);
4525 /* In the case of NAME == 0 or NAME != 1, for BIT_IOR_EXPR defining
4526 statement of NAME we can assert both operands of the BIT_IOR_EXPR
4528 if (((comp_code
== EQ_EXPR
&& integer_zerop (val
))
4529 || (comp_code
== NE_EXPR
&& integer_onep (val
))))
4531 gimple def_stmt
= SSA_NAME_DEF_STMT (name
);
4533 /* For BIT_IOR_EXPR only if NAME == 0 both operands have
4534 necessarily zero value, or if type-precision is one. */
4535 if (is_gimple_assign (def_stmt
)
4536 && (gimple_assign_rhs_code (def_stmt
) == BIT_IOR_EXPR
4537 && (TYPE_PRECISION (TREE_TYPE (name
)) == 1
4538 || comp_code
== EQ_EXPR
)))
4540 tree op0
= gimple_assign_rhs1 (def_stmt
);
4541 tree op1
= gimple_assign_rhs2 (def_stmt
);
4542 retval
|= register_edge_assert_for_1 (op0
, EQ_EXPR
, e
, si
);
4543 retval
|= register_edge_assert_for_1 (op1
, EQ_EXPR
, e
, si
);
4551 /* Determine whether the outgoing edges of BB should receive an
4552 ASSERT_EXPR for each of the operands of BB's LAST statement.
4553 The last statement of BB must be a COND_EXPR.
4555 If any of the sub-graphs rooted at BB have an interesting use of
4556 the predicate operands, an assert location node is added to the
4557 list of assertions for the corresponding operands. */
4560 find_conditional_asserts (basic_block bb
, gimple last
)
4563 gimple_stmt_iterator bsi
;
4569 need_assert
= false;
4570 bsi
= gsi_for_stmt (last
);
4572 /* Look for uses of the operands in each of the sub-graphs
4573 rooted at BB. We need to check each of the outgoing edges
4574 separately, so that we know what kind of ASSERT_EXPR to
4576 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
4581 /* Register the necessary assertions for each operand in the
4582 conditional predicate. */
4583 FOR_EACH_SSA_TREE_OPERAND (op
, last
, iter
, SSA_OP_USE
)
4585 need_assert
|= register_edge_assert_for (op
, e
, bsi
,
4586 gimple_cond_code (last
),
4587 gimple_cond_lhs (last
),
4588 gimple_cond_rhs (last
));
4601 /* Compare two case labels sorting first by the destination bb index
4602 and then by the case value. */
4605 compare_case_labels (const void *p1
, const void *p2
)
4607 const struct case_info
*ci1
= (const struct case_info
*) p1
;
4608 const struct case_info
*ci2
= (const struct case_info
*) p2
;
4609 int idx1
= ci1
->bb
->index
;
4610 int idx2
= ci2
->bb
->index
;
4614 else if (idx1
== idx2
)
4616 /* Make sure the default label is first in a group. */
4617 if (!CASE_LOW (ci1
->expr
))
4619 else if (!CASE_LOW (ci2
->expr
))
4622 return tree_int_cst_compare (CASE_LOW (ci1
->expr
),
4623 CASE_LOW (ci2
->expr
));
4629 /* Determine whether the outgoing edges of BB should receive an
4630 ASSERT_EXPR for each of the operands of BB's LAST statement.
4631 The last statement of BB must be a SWITCH_EXPR.
4633 If any of the sub-graphs rooted at BB have an interesting use of
4634 the predicate operands, an assert location node is added to the
4635 list of assertions for the corresponding operands. */
4638 find_switch_asserts (basic_block bb
, gimple last
)
4641 gimple_stmt_iterator bsi
;
4644 struct case_info
*ci
;
4645 size_t n
= gimple_switch_num_labels (last
);
4646 #if GCC_VERSION >= 4000
4649 /* Work around GCC 3.4 bug (PR 37086). */
4650 volatile unsigned int idx
;
4653 need_assert
= false;
4654 bsi
= gsi_for_stmt (last
);
4655 op
= gimple_switch_index (last
);
4656 if (TREE_CODE (op
) != SSA_NAME
)
4659 /* Build a vector of case labels sorted by destination label. */
4660 ci
= XNEWVEC (struct case_info
, n
);
4661 for (idx
= 0; idx
< n
; ++idx
)
4663 ci
[idx
].expr
= gimple_switch_label (last
, idx
);
4664 ci
[idx
].bb
= label_to_block (CASE_LABEL (ci
[idx
].expr
));
4666 qsort (ci
, n
, sizeof (struct case_info
), compare_case_labels
);
4668 for (idx
= 0; idx
< n
; ++idx
)
4671 tree cl
= ci
[idx
].expr
;
4672 basic_block cbb
= ci
[idx
].bb
;
4674 min
= CASE_LOW (cl
);
4675 max
= CASE_HIGH (cl
);
4677 /* If there are multiple case labels with the same destination
4678 we need to combine them to a single value range for the edge. */
4679 if (idx
+ 1 < n
&& cbb
== ci
[idx
+ 1].bb
)
4681 /* Skip labels until the last of the group. */
4684 } while (idx
< n
&& cbb
== ci
[idx
].bb
);
4687 /* Pick up the maximum of the case label range. */
4688 if (CASE_HIGH (ci
[idx
].expr
))
4689 max
= CASE_HIGH (ci
[idx
].expr
);
4691 max
= CASE_LOW (ci
[idx
].expr
);
4694 /* Nothing to do if the range includes the default label until we
4695 can register anti-ranges. */
4696 if (min
== NULL_TREE
)
4699 /* Find the edge to register the assert expr on. */
4700 e
= find_edge (bb
, cbb
);
4702 /* Register the necessary assertions for the operand in the
4704 need_assert
|= register_edge_assert_for (op
, e
, bsi
,
4705 max
? GE_EXPR
: EQ_EXPR
,
4707 fold_convert (TREE_TYPE (op
),
4711 need_assert
|= register_edge_assert_for (op
, e
, bsi
, LE_EXPR
,
4713 fold_convert (TREE_TYPE (op
),
4723 /* Traverse all the statements in block BB looking for statements that
4724 may generate useful assertions for the SSA names in their operand.
4725 If a statement produces a useful assertion A for name N_i, then the
4726 list of assertions already generated for N_i is scanned to
4727 determine if A is actually needed.
4729 If N_i already had the assertion A at a location dominating the
4730 current location, then nothing needs to be done. Otherwise, the
4731 new location for A is recorded instead.
4733 1- For every statement S in BB, all the variables used by S are
4734 added to bitmap FOUND_IN_SUBGRAPH.
4736 2- If statement S uses an operand N in a way that exposes a known
4737 value range for N, then if N was not already generated by an
4738 ASSERT_EXPR, create a new assert location for N. For instance,
4739 if N is a pointer and the statement dereferences it, we can
4740 assume that N is not NULL.
4742 3- COND_EXPRs are a special case of #2. We can derive range
4743 information from the predicate but need to insert different
4744 ASSERT_EXPRs for each of the sub-graphs rooted at the
4745 conditional block. If the last statement of BB is a conditional
4746 expression of the form 'X op Y', then
4748 a) Remove X and Y from the set FOUND_IN_SUBGRAPH.
4750 b) If the conditional is the only entry point to the sub-graph
4751 corresponding to the THEN_CLAUSE, recurse into it. On
4752 return, if X and/or Y are marked in FOUND_IN_SUBGRAPH, then
4753 an ASSERT_EXPR is added for the corresponding variable.
4755 c) Repeat step (b) on the ELSE_CLAUSE.
4757 d) Mark X and Y in FOUND_IN_SUBGRAPH.
4766 In this case, an assertion on the THEN clause is useful to
4767 determine that 'a' is always 9 on that edge. However, an assertion
4768 on the ELSE clause would be unnecessary.
4770 4- If BB does not end in a conditional expression, then we recurse
4771 into BB's dominator children.
4773 At the end of the recursive traversal, every SSA name will have a
4774 list of locations where ASSERT_EXPRs should be added. When a new
4775 location for name N is found, it is registered by calling
4776 register_new_assert_for. That function keeps track of all the
4777 registered assertions to prevent adding unnecessary assertions.
4778 For instance, if a pointer P_4 is dereferenced more than once in a
4779 dominator tree, only the location dominating all the dereference of
4780 P_4 will receive an ASSERT_EXPR.
4782 If this function returns true, then it means that there are names
4783 for which we need to generate ASSERT_EXPRs. Those assertions are
4784 inserted by process_assert_insertions. */
4787 find_assert_locations_1 (basic_block bb
, sbitmap live
)
4789 gimple_stmt_iterator si
;
4794 need_assert
= false;
4795 last
= last_stmt (bb
);
4797 /* If BB's last statement is a conditional statement involving integer
4798 operands, determine if we need to add ASSERT_EXPRs. */
4800 && gimple_code (last
) == GIMPLE_COND
4801 && !fp_predicate (last
)
4802 && !ZERO_SSA_OPERANDS (last
, SSA_OP_USE
))
4803 need_assert
|= find_conditional_asserts (bb
, last
);
4805 /* If BB's last statement is a switch statement involving integer
4806 operands, determine if we need to add ASSERT_EXPRs. */
4808 && gimple_code (last
) == GIMPLE_SWITCH
4809 && !ZERO_SSA_OPERANDS (last
, SSA_OP_USE
))
4810 need_assert
|= find_switch_asserts (bb
, last
);
4812 /* Traverse all the statements in BB marking used names and looking
4813 for statements that may infer assertions for their used operands. */
4814 for (si
= gsi_start_bb (bb
); !gsi_end_p (si
); gsi_next (&si
))
4820 stmt
= gsi_stmt (si
);
4822 if (is_gimple_debug (stmt
))
4825 /* See if we can derive an assertion for any of STMT's operands. */
4826 FOR_EACH_SSA_TREE_OPERAND (op
, stmt
, i
, SSA_OP_USE
)
4829 enum tree_code comp_code
;
4831 /* Mark OP in our live bitmap. */
4832 SET_BIT (live
, SSA_NAME_VERSION (op
));
4834 /* If OP is used in such a way that we can infer a value
4835 range for it, and we don't find a previous assertion for
4836 it, create a new assertion location node for OP. */
4837 if (infer_value_range (stmt
, op
, &comp_code
, &value
))
4839 /* If we are able to infer a nonzero value range for OP,
4840 then walk backwards through the use-def chain to see if OP
4841 was set via a typecast.
4843 If so, then we can also infer a nonzero value range
4844 for the operand of the NOP_EXPR. */
4845 if (comp_code
== NE_EXPR
&& integer_zerop (value
))
4848 gimple def_stmt
= SSA_NAME_DEF_STMT (t
);
4850 while (is_gimple_assign (def_stmt
)
4851 && gimple_assign_rhs_code (def_stmt
) == NOP_EXPR
4853 (gimple_assign_rhs1 (def_stmt
)) == SSA_NAME
4855 (TREE_TYPE (gimple_assign_rhs1 (def_stmt
))))
4857 t
= gimple_assign_rhs1 (def_stmt
);
4858 def_stmt
= SSA_NAME_DEF_STMT (t
);
4860 /* Note we want to register the assert for the
4861 operand of the NOP_EXPR after SI, not after the
4863 if (! has_single_use (t
))
4865 register_new_assert_for (t
, t
, comp_code
, value
,
4872 /* If OP is used only once, namely in this STMT, don't
4873 bother creating an ASSERT_EXPR for it. Such an
4874 ASSERT_EXPR would do nothing but increase compile time. */
4875 if (!has_single_use (op
))
4877 register_new_assert_for (op
, op
, comp_code
, value
,
4885 /* Traverse all PHI nodes in BB marking used operands. */
4886 for (si
= gsi_start_phis (bb
); !gsi_end_p(si
); gsi_next (&si
))
4888 use_operand_p arg_p
;
4890 phi
= gsi_stmt (si
);
4892 FOR_EACH_PHI_ARG (arg_p
, phi
, i
, SSA_OP_USE
)
4894 tree arg
= USE_FROM_PTR (arg_p
);
4895 if (TREE_CODE (arg
) == SSA_NAME
)
4896 SET_BIT (live
, SSA_NAME_VERSION (arg
));
4903 /* Do an RPO walk over the function computing SSA name liveness
4904 on-the-fly and deciding on assert expressions to insert.
4905 Returns true if there are assert expressions to be inserted. */
4908 find_assert_locations (void)
4910 int *rpo
= XCNEWVEC (int, last_basic_block
+ NUM_FIXED_BLOCKS
);
4911 int *bb_rpo
= XCNEWVEC (int, last_basic_block
+ NUM_FIXED_BLOCKS
);
4912 int *last_rpo
= XCNEWVEC (int, last_basic_block
+ NUM_FIXED_BLOCKS
);
4916 live
= XCNEWVEC (sbitmap
, last_basic_block
+ NUM_FIXED_BLOCKS
);
4917 rpo_cnt
= pre_and_rev_post_order_compute (NULL
, rpo
, false);
4918 for (i
= 0; i
< rpo_cnt
; ++i
)
4921 need_asserts
= false;
4922 for (i
= rpo_cnt
-1; i
>= 0; --i
)
4924 basic_block bb
= BASIC_BLOCK (rpo
[i
]);
4930 live
[rpo
[i
]] = sbitmap_alloc (num_ssa_names
);
4931 sbitmap_zero (live
[rpo
[i
]]);
4934 /* Process BB and update the live information with uses in
4936 need_asserts
|= find_assert_locations_1 (bb
, live
[rpo
[i
]]);
4938 /* Merge liveness into the predecessor blocks and free it. */
4939 if (!sbitmap_empty_p (live
[rpo
[i
]]))
4942 FOR_EACH_EDGE (e
, ei
, bb
->preds
)
4944 int pred
= e
->src
->index
;
4945 if (e
->flags
& EDGE_DFS_BACK
)
4950 live
[pred
] = sbitmap_alloc (num_ssa_names
);
4951 sbitmap_zero (live
[pred
]);
4953 sbitmap_a_or_b (live
[pred
], live
[pred
], live
[rpo
[i
]]);
4955 if (bb_rpo
[pred
] < pred_rpo
)
4956 pred_rpo
= bb_rpo
[pred
];
4959 /* Record the RPO number of the last visited block that needs
4960 live information from this block. */
4961 last_rpo
[rpo
[i
]] = pred_rpo
;
4965 sbitmap_free (live
[rpo
[i
]]);
4966 live
[rpo
[i
]] = NULL
;
4969 /* We can free all successors live bitmaps if all their
4970 predecessors have been visited already. */
4971 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
4972 if (last_rpo
[e
->dest
->index
] == i
4973 && live
[e
->dest
->index
])
4975 sbitmap_free (live
[e
->dest
->index
]);
4976 live
[e
->dest
->index
] = NULL
;
4981 XDELETEVEC (bb_rpo
);
4982 XDELETEVEC (last_rpo
);
4983 for (i
= 0; i
< last_basic_block
+ NUM_FIXED_BLOCKS
; ++i
)
4985 sbitmap_free (live
[i
]);
4988 return need_asserts
;
4991 /* Create an ASSERT_EXPR for NAME and insert it in the location
4992 indicated by LOC. Return true if we made any edge insertions. */
4995 process_assert_insertions_for (tree name
, assert_locus_t loc
)
4997 /* Build the comparison expression NAME_i COMP_CODE VAL. */
5004 /* If we have X <=> X do not insert an assert expr for that. */
5005 if (loc
->expr
== loc
->val
)
5008 cond
= build2 (loc
->comp_code
, boolean_type_node
, loc
->expr
, loc
->val
);
5009 assert_stmt
= build_assert_expr_for (cond
, name
);
5012 /* We have been asked to insert the assertion on an edge. This
5013 is used only by COND_EXPR and SWITCH_EXPR assertions. */
5014 gcc_checking_assert (gimple_code (gsi_stmt (loc
->si
)) == GIMPLE_COND
5015 || (gimple_code (gsi_stmt (loc
->si
))
5018 gsi_insert_on_edge (loc
->e
, assert_stmt
);
5022 /* Otherwise, we can insert right after LOC->SI iff the
5023 statement must not be the last statement in the block. */
5024 stmt
= gsi_stmt (loc
->si
);
5025 if (!stmt_ends_bb_p (stmt
))
5027 gsi_insert_after (&loc
->si
, assert_stmt
, GSI_SAME_STMT
);
5031 /* If STMT must be the last statement in BB, we can only insert new
5032 assertions on the non-abnormal edge out of BB. Note that since
5033 STMT is not control flow, there may only be one non-abnormal edge
5035 FOR_EACH_EDGE (e
, ei
, loc
->bb
->succs
)
5036 if (!(e
->flags
& EDGE_ABNORMAL
))
5038 gsi_insert_on_edge (e
, assert_stmt
);
5046 /* Process all the insertions registered for every name N_i registered
5047 in NEED_ASSERT_FOR. The list of assertions to be inserted are
5048 found in ASSERTS_FOR[i]. */
5051 process_assert_insertions (void)
5055 bool update_edges_p
= false;
5056 int num_asserts
= 0;
5058 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
5059 dump_all_asserts (dump_file
);
5061 EXECUTE_IF_SET_IN_BITMAP (need_assert_for
, 0, i
, bi
)
5063 assert_locus_t loc
= asserts_for
[i
];
5068 assert_locus_t next
= loc
->next
;
5069 update_edges_p
|= process_assert_insertions_for (ssa_name (i
), loc
);
5077 gsi_commit_edge_inserts ();
5079 statistics_counter_event (cfun
, "Number of ASSERT_EXPR expressions inserted",
5084 /* Traverse the flowgraph looking for conditional jumps to insert range
5085 expressions. These range expressions are meant to provide information
5086 to optimizations that need to reason in terms of value ranges. They
5087 will not be expanded into RTL. For instance, given:
5096 this pass will transform the code into:
5102 x = ASSERT_EXPR <x, x < y>
5107 y = ASSERT_EXPR <y, x <= y>
5111 The idea is that once copy and constant propagation have run, other
5112 optimizations will be able to determine what ranges of values can 'x'
5113 take in different paths of the code, simply by checking the reaching
5114 definition of 'x'. */
5117 insert_range_assertions (void)
5119 need_assert_for
= BITMAP_ALLOC (NULL
);
5120 asserts_for
= XCNEWVEC (assert_locus_t
, num_ssa_names
);
5122 calculate_dominance_info (CDI_DOMINATORS
);
5124 if (find_assert_locations ())
5126 process_assert_insertions ();
5127 update_ssa (TODO_update_ssa_no_phi
);
5130 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
5132 fprintf (dump_file
, "\nSSA form after inserting ASSERT_EXPRs\n");
5133 dump_function_to_file (current_function_decl
, dump_file
, dump_flags
);
5137 BITMAP_FREE (need_assert_for
);
5140 /* Checks one ARRAY_REF in REF, located at LOCUS. Ignores flexible arrays
5141 and "struct" hacks. If VRP can determine that the
5142 array subscript is a constant, check if it is outside valid
5143 range. If the array subscript is a RANGE, warn if it is
5144 non-overlapping with valid range.
5145 IGNORE_OFF_BY_ONE is true if the ARRAY_REF is inside a ADDR_EXPR. */
5148 check_array_ref (location_t location
, tree ref
, bool ignore_off_by_one
)
5150 value_range_t
* vr
= NULL
;
5151 tree low_sub
, up_sub
;
5152 tree low_bound
, up_bound
, up_bound_p1
;
5155 if (TREE_NO_WARNING (ref
))
5158 low_sub
= up_sub
= TREE_OPERAND (ref
, 1);
5159 up_bound
= array_ref_up_bound (ref
);
5161 /* Can not check flexible arrays. */
5163 || TREE_CODE (up_bound
) != INTEGER_CST
)
5166 /* Accesses to trailing arrays via pointers may access storage
5167 beyond the types array bounds. */
5168 base
= get_base_address (ref
);
5169 if (base
&& TREE_CODE (base
) == MEM_REF
)
5171 tree cref
, next
= NULL_TREE
;
5173 if (TREE_CODE (TREE_OPERAND (ref
, 0)) != COMPONENT_REF
)
5176 cref
= TREE_OPERAND (ref
, 0);
5177 if (TREE_CODE (TREE_TYPE (TREE_OPERAND (cref
, 0))) == RECORD_TYPE
)
5178 for (next
= DECL_CHAIN (TREE_OPERAND (cref
, 1));
5179 next
&& TREE_CODE (next
) != FIELD_DECL
;
5180 next
= DECL_CHAIN (next
))
5183 /* If this is the last field in a struct type or a field in a
5184 union type do not warn. */
5189 low_bound
= array_ref_low_bound (ref
);
5190 up_bound_p1
= int_const_binop (PLUS_EXPR
, up_bound
, integer_one_node
);
5192 if (TREE_CODE (low_sub
) == SSA_NAME
)
5194 vr
= get_value_range (low_sub
);
5195 if (vr
->type
== VR_RANGE
|| vr
->type
== VR_ANTI_RANGE
)
5197 low_sub
= vr
->type
== VR_RANGE
? vr
->max
: vr
->min
;
5198 up_sub
= vr
->type
== VR_RANGE
? vr
->min
: vr
->max
;
5202 if (vr
&& vr
->type
== VR_ANTI_RANGE
)
5204 if (TREE_CODE (up_sub
) == INTEGER_CST
5205 && tree_int_cst_lt (up_bound
, up_sub
)
5206 && TREE_CODE (low_sub
) == INTEGER_CST
5207 && tree_int_cst_lt (low_sub
, low_bound
))
5209 warning_at (location
, OPT_Warray_bounds
,
5210 "array subscript is outside array bounds");
5211 TREE_NO_WARNING (ref
) = 1;
5214 else if (TREE_CODE (up_sub
) == INTEGER_CST
5215 && (ignore_off_by_one
5216 ? (tree_int_cst_lt (up_bound
, up_sub
)
5217 && !tree_int_cst_equal (up_bound_p1
, up_sub
))
5218 : (tree_int_cst_lt (up_bound
, up_sub
)
5219 || tree_int_cst_equal (up_bound_p1
, up_sub
))))
5221 warning_at (location
, OPT_Warray_bounds
,
5222 "array subscript is above array bounds");
5223 TREE_NO_WARNING (ref
) = 1;
5225 else if (TREE_CODE (low_sub
) == INTEGER_CST
5226 && tree_int_cst_lt (low_sub
, low_bound
))
5228 warning_at (location
, OPT_Warray_bounds
,
5229 "array subscript is below array bounds");
5230 TREE_NO_WARNING (ref
) = 1;
5234 /* Searches if the expr T, located at LOCATION computes
5235 address of an ARRAY_REF, and call check_array_ref on it. */
5238 search_for_addr_array (tree t
, location_t location
)
5240 while (TREE_CODE (t
) == SSA_NAME
)
5242 gimple g
= SSA_NAME_DEF_STMT (t
);
5244 if (gimple_code (g
) != GIMPLE_ASSIGN
)
5247 if (get_gimple_rhs_class (gimple_assign_rhs_code (g
))
5248 != GIMPLE_SINGLE_RHS
)
5251 t
= gimple_assign_rhs1 (g
);
5255 /* We are only interested in addresses of ARRAY_REF's. */
5256 if (TREE_CODE (t
) != ADDR_EXPR
)
5259 /* Check each ARRAY_REFs in the reference chain. */
5262 if (TREE_CODE (t
) == ARRAY_REF
)
5263 check_array_ref (location
, t
, true /*ignore_off_by_one*/);
5265 t
= TREE_OPERAND (t
, 0);
5267 while (handled_component_p (t
));
5269 if (TREE_CODE (t
) == MEM_REF
5270 && TREE_CODE (TREE_OPERAND (t
, 0)) == ADDR_EXPR
5271 && !TREE_NO_WARNING (t
))
5273 tree tem
= TREE_OPERAND (TREE_OPERAND (t
, 0), 0);
5274 tree low_bound
, up_bound
, el_sz
;
5276 if (TREE_CODE (TREE_TYPE (tem
)) != ARRAY_TYPE
5277 || TREE_CODE (TREE_TYPE (TREE_TYPE (tem
))) == ARRAY_TYPE
5278 || !TYPE_DOMAIN (TREE_TYPE (tem
)))
5281 low_bound
= TYPE_MIN_VALUE (TYPE_DOMAIN (TREE_TYPE (tem
)));
5282 up_bound
= TYPE_MAX_VALUE (TYPE_DOMAIN (TREE_TYPE (tem
)));
5283 el_sz
= TYPE_SIZE_UNIT (TREE_TYPE (TREE_TYPE (tem
)));
5285 || TREE_CODE (low_bound
) != INTEGER_CST
5287 || TREE_CODE (up_bound
) != INTEGER_CST
5289 || TREE_CODE (el_sz
) != INTEGER_CST
)
5292 idx
= mem_ref_offset (t
);
5293 idx
= double_int_sdiv (idx
, tree_to_double_int (el_sz
), TRUNC_DIV_EXPR
);
5294 if (double_int_scmp (idx
, double_int_zero
) < 0)
5296 warning_at (location
, OPT_Warray_bounds
,
5297 "array subscript is below array bounds");
5298 TREE_NO_WARNING (t
) = 1;
5300 else if (double_int_scmp (idx
,
5303 (tree_to_double_int (up_bound
),
5305 (tree_to_double_int (low_bound
))),
5306 double_int_one
)) > 0)
5308 warning_at (location
, OPT_Warray_bounds
,
5309 "array subscript is above array bounds");
5310 TREE_NO_WARNING (t
) = 1;
5315 /* walk_tree() callback that checks if *TP is
5316 an ARRAY_REF inside an ADDR_EXPR (in which an array
5317 subscript one outside the valid range is allowed). Call
5318 check_array_ref for each ARRAY_REF found. The location is
5322 check_array_bounds (tree
*tp
, int *walk_subtree
, void *data
)
5325 struct walk_stmt_info
*wi
= (struct walk_stmt_info
*) data
;
5326 location_t location
;
5328 if (EXPR_HAS_LOCATION (t
))
5329 location
= EXPR_LOCATION (t
);
5332 location_t
*locp
= (location_t
*) wi
->info
;
5336 *walk_subtree
= TRUE
;
5338 if (TREE_CODE (t
) == ARRAY_REF
)
5339 check_array_ref (location
, t
, false /*ignore_off_by_one*/);
5341 if (TREE_CODE (t
) == MEM_REF
5342 || (TREE_CODE (t
) == RETURN_EXPR
&& TREE_OPERAND (t
, 0)))
5343 search_for_addr_array (TREE_OPERAND (t
, 0), location
);
5345 if (TREE_CODE (t
) == ADDR_EXPR
)
5346 *walk_subtree
= FALSE
;
5351 /* Walk over all statements of all reachable BBs and call check_array_bounds
5355 check_all_array_refs (void)
5358 gimple_stmt_iterator si
;
5364 bool executable
= false;
5366 /* Skip blocks that were found to be unreachable. */
5367 FOR_EACH_EDGE (e
, ei
, bb
->preds
)
5368 executable
|= !!(e
->flags
& EDGE_EXECUTABLE
);
5372 for (si
= gsi_start_bb (bb
); !gsi_end_p (si
); gsi_next (&si
))
5374 gimple stmt
= gsi_stmt (si
);
5375 struct walk_stmt_info wi
;
5376 if (!gimple_has_location (stmt
))
5379 if (is_gimple_call (stmt
))
5382 size_t n
= gimple_call_num_args (stmt
);
5383 for (i
= 0; i
< n
; i
++)
5385 tree arg
= gimple_call_arg (stmt
, i
);
5386 search_for_addr_array (arg
, gimple_location (stmt
));
5391 memset (&wi
, 0, sizeof (wi
));
5392 wi
.info
= CONST_CAST (void *, (const void *)
5393 gimple_location_ptr (stmt
));
5395 walk_gimple_op (gsi_stmt (si
),
5403 /* Convert range assertion expressions into the implied copies and
5404 copy propagate away the copies. Doing the trivial copy propagation
5405 here avoids the need to run the full copy propagation pass after
5408 FIXME, this will eventually lead to copy propagation removing the
5409 names that had useful range information attached to them. For
5410 instance, if we had the assertion N_i = ASSERT_EXPR <N_j, N_j > 3>,
5411 then N_i will have the range [3, +INF].
5413 However, by converting the assertion into the implied copy
5414 operation N_i = N_j, we will then copy-propagate N_j into the uses
5415 of N_i and lose the range information. We may want to hold on to
5416 ASSERT_EXPRs a little while longer as the ranges could be used in
5417 things like jump threading.
5419 The problem with keeping ASSERT_EXPRs around is that passes after
5420 VRP need to handle them appropriately.
5422 Another approach would be to make the range information a first
5423 class property of the SSA_NAME so that it can be queried from
5424 any pass. This is made somewhat more complex by the need for
5425 multiple ranges to be associated with one SSA_NAME. */
5428 remove_range_assertions (void)
5431 gimple_stmt_iterator si
;
5433 /* Note that the BSI iterator bump happens at the bottom of the
5434 loop and no bump is necessary if we're removing the statement
5435 referenced by the current BSI. */
5437 for (si
= gsi_start_bb (bb
); !gsi_end_p (si
);)
5439 gimple stmt
= gsi_stmt (si
);
5442 if (is_gimple_assign (stmt
)
5443 && gimple_assign_rhs_code (stmt
) == ASSERT_EXPR
)
5445 tree rhs
= gimple_assign_rhs1 (stmt
);
5447 tree cond
= fold (ASSERT_EXPR_COND (rhs
));
5448 use_operand_p use_p
;
5449 imm_use_iterator iter
;
5451 gcc_assert (cond
!= boolean_false_node
);
5453 /* Propagate the RHS into every use of the LHS. */
5454 var
= ASSERT_EXPR_VAR (rhs
);
5455 FOR_EACH_IMM_USE_STMT (use_stmt
, iter
,
5456 gimple_assign_lhs (stmt
))
5457 FOR_EACH_IMM_USE_ON_STMT (use_p
, iter
)
5459 SET_USE (use_p
, var
);
5460 gcc_assert (TREE_CODE (var
) == SSA_NAME
);
5463 /* And finally, remove the copy, it is not needed. */
5464 gsi_remove (&si
, true);
5465 release_defs (stmt
);
5473 /* Return true if STMT is interesting for VRP. */
5476 stmt_interesting_for_vrp (gimple stmt
)
5478 if (gimple_code (stmt
) == GIMPLE_PHI
5479 && is_gimple_reg (gimple_phi_result (stmt
))
5480 && (INTEGRAL_TYPE_P (TREE_TYPE (gimple_phi_result (stmt
)))
5481 || POINTER_TYPE_P (TREE_TYPE (gimple_phi_result (stmt
)))))
5483 else if (is_gimple_assign (stmt
) || is_gimple_call (stmt
))
5485 tree lhs
= gimple_get_lhs (stmt
);
5487 /* In general, assignments with virtual operands are not useful
5488 for deriving ranges, with the obvious exception of calls to
5489 builtin functions. */
5490 if (lhs
&& TREE_CODE (lhs
) == SSA_NAME
5491 && (INTEGRAL_TYPE_P (TREE_TYPE (lhs
))
5492 || POINTER_TYPE_P (TREE_TYPE (lhs
)))
5493 && ((is_gimple_call (stmt
)
5494 && gimple_call_fndecl (stmt
) != NULL_TREE
5495 && DECL_BUILT_IN (gimple_call_fndecl (stmt
)))
5496 || !gimple_vuse (stmt
)))
5499 else if (gimple_code (stmt
) == GIMPLE_COND
5500 || gimple_code (stmt
) == GIMPLE_SWITCH
)
5507 /* Initialize local data structures for VRP. */
5510 vrp_initialize (void)
5514 values_propagated
= false;
5515 num_vr_values
= num_ssa_names
;
5516 vr_value
= XCNEWVEC (value_range_t
*, num_vr_values
);
5517 vr_phi_edge_counts
= XCNEWVEC (int, num_ssa_names
);
5521 gimple_stmt_iterator si
;
5523 for (si
= gsi_start_phis (bb
); !gsi_end_p (si
); gsi_next (&si
))
5525 gimple phi
= gsi_stmt (si
);
5526 if (!stmt_interesting_for_vrp (phi
))
5528 tree lhs
= PHI_RESULT (phi
);
5529 set_value_range_to_varying (get_value_range (lhs
));
5530 prop_set_simulate_again (phi
, false);
5533 prop_set_simulate_again (phi
, true);
5536 for (si
= gsi_start_bb (bb
); !gsi_end_p (si
); gsi_next (&si
))
5538 gimple stmt
= gsi_stmt (si
);
5540 /* If the statement is a control insn, then we do not
5541 want to avoid simulating the statement once. Failure
5542 to do so means that those edges will never get added. */
5543 if (stmt_ends_bb_p (stmt
))
5544 prop_set_simulate_again (stmt
, true);
5545 else if (!stmt_interesting_for_vrp (stmt
))
5549 FOR_EACH_SSA_TREE_OPERAND (def
, stmt
, i
, SSA_OP_DEF
)
5550 set_value_range_to_varying (get_value_range (def
));
5551 prop_set_simulate_again (stmt
, false);
5554 prop_set_simulate_again (stmt
, true);
5559 /* Return the singleton value-range for NAME or NAME. */
5562 vrp_valueize (tree name
)
5564 if (TREE_CODE (name
) == SSA_NAME
)
5566 value_range_t
*vr
= get_value_range (name
);
5567 if (vr
->type
== VR_RANGE
5568 && (vr
->min
== vr
->max
5569 || operand_equal_p (vr
->min
, vr
->max
, 0)))
5575 /* Visit assignment STMT. If it produces an interesting range, record
5576 the SSA name in *OUTPUT_P. */
5578 static enum ssa_prop_result
5579 vrp_visit_assignment_or_call (gimple stmt
, tree
*output_p
)
5583 enum gimple_code code
= gimple_code (stmt
);
5584 lhs
= gimple_get_lhs (stmt
);
5586 /* We only keep track of ranges in integral and pointer types. */
5587 if (TREE_CODE (lhs
) == SSA_NAME
5588 && ((INTEGRAL_TYPE_P (TREE_TYPE (lhs
))
5589 /* It is valid to have NULL MIN/MAX values on a type. See
5590 build_range_type. */
5591 && TYPE_MIN_VALUE (TREE_TYPE (lhs
))
5592 && TYPE_MAX_VALUE (TREE_TYPE (lhs
)))
5593 || POINTER_TYPE_P (TREE_TYPE (lhs
))))
5595 value_range_t new_vr
= { VR_UNDEFINED
, NULL_TREE
, NULL_TREE
, NULL
};
5597 /* Try folding the statement to a constant first. */
5598 tree tem
= gimple_fold_stmt_to_constant (stmt
, vrp_valueize
);
5599 if (tem
&& !is_overflow_infinity (tem
))
5600 set_value_range (&new_vr
, VR_RANGE
, tem
, tem
, NULL
);
5601 /* Then dispatch to value-range extracting functions. */
5602 else if (code
== GIMPLE_CALL
)
5603 extract_range_basic (&new_vr
, stmt
);
5605 extract_range_from_assignment (&new_vr
, stmt
);
5607 if (update_value_range (lhs
, &new_vr
))
5611 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
5613 fprintf (dump_file
, "Found new range for ");
5614 print_generic_expr (dump_file
, lhs
, 0);
5615 fprintf (dump_file
, ": ");
5616 dump_value_range (dump_file
, &new_vr
);
5617 fprintf (dump_file
, "\n\n");
5620 if (new_vr
.type
== VR_VARYING
)
5621 return SSA_PROP_VARYING
;
5623 return SSA_PROP_INTERESTING
;
5626 return SSA_PROP_NOT_INTERESTING
;
5629 /* Every other statement produces no useful ranges. */
5630 FOR_EACH_SSA_TREE_OPERAND (def
, stmt
, iter
, SSA_OP_DEF
)
5631 set_value_range_to_varying (get_value_range (def
));
5633 return SSA_PROP_VARYING
;
5636 /* Helper that gets the value range of the SSA_NAME with version I
5637 or a symbolic range containing the SSA_NAME only if the value range
5638 is varying or undefined. */
5640 static inline value_range_t
5641 get_vr_for_comparison (int i
)
5643 value_range_t vr
= *get_value_range (ssa_name (i
));
5645 /* If name N_i does not have a valid range, use N_i as its own
5646 range. This allows us to compare against names that may
5647 have N_i in their ranges. */
5648 if (vr
.type
== VR_VARYING
|| vr
.type
== VR_UNDEFINED
)
5651 vr
.min
= ssa_name (i
);
5652 vr
.max
= ssa_name (i
);
5658 /* Compare all the value ranges for names equivalent to VAR with VAL
5659 using comparison code COMP. Return the same value returned by
5660 compare_range_with_value, including the setting of
5661 *STRICT_OVERFLOW_P. */
5664 compare_name_with_value (enum tree_code comp
, tree var
, tree val
,
5665 bool *strict_overflow_p
)
5671 int used_strict_overflow
;
5673 value_range_t equiv_vr
;
5675 /* Get the set of equivalences for VAR. */
5676 e
= get_value_range (var
)->equiv
;
5678 /* Start at -1. Set it to 0 if we do a comparison without relying
5679 on overflow, or 1 if all comparisons rely on overflow. */
5680 used_strict_overflow
= -1;
5682 /* Compare vars' value range with val. */
5683 equiv_vr
= get_vr_for_comparison (SSA_NAME_VERSION (var
));
5685 retval
= compare_range_with_value (comp
, &equiv_vr
, val
, &sop
);
5687 used_strict_overflow
= sop
? 1 : 0;
5689 /* If the equiv set is empty we have done all work we need to do. */
5693 && used_strict_overflow
> 0)
5694 *strict_overflow_p
= true;
5698 EXECUTE_IF_SET_IN_BITMAP (e
, 0, i
, bi
)
5700 equiv_vr
= get_vr_for_comparison (i
);
5702 t
= compare_range_with_value (comp
, &equiv_vr
, val
, &sop
);
5705 /* If we get different answers from different members
5706 of the equivalence set this check must be in a dead
5707 code region. Folding it to a trap representation
5708 would be correct here. For now just return don't-know. */
5718 used_strict_overflow
= 0;
5719 else if (used_strict_overflow
< 0)
5720 used_strict_overflow
= 1;
5725 && used_strict_overflow
> 0)
5726 *strict_overflow_p
= true;
5732 /* Given a comparison code COMP and names N1 and N2, compare all the
5733 ranges equivalent to N1 against all the ranges equivalent to N2
5734 to determine the value of N1 COMP N2. Return the same value
5735 returned by compare_ranges. Set *STRICT_OVERFLOW_P to indicate
5736 whether we relied on an overflow infinity in the comparison. */
5740 compare_names (enum tree_code comp
, tree n1
, tree n2
,
5741 bool *strict_overflow_p
)
5745 bitmap_iterator bi1
, bi2
;
5747 int used_strict_overflow
;
5748 static bitmap_obstack
*s_obstack
= NULL
;
5749 static bitmap s_e1
= NULL
, s_e2
= NULL
;
5751 /* Compare the ranges of every name equivalent to N1 against the
5752 ranges of every name equivalent to N2. */
5753 e1
= get_value_range (n1
)->equiv
;
5754 e2
= get_value_range (n2
)->equiv
;
5756 /* Use the fake bitmaps if e1 or e2 are not available. */
5757 if (s_obstack
== NULL
)
5759 s_obstack
= XNEW (bitmap_obstack
);
5760 bitmap_obstack_initialize (s_obstack
);
5761 s_e1
= BITMAP_ALLOC (s_obstack
);
5762 s_e2
= BITMAP_ALLOC (s_obstack
);
5769 /* Add N1 and N2 to their own set of equivalences to avoid
5770 duplicating the body of the loop just to check N1 and N2
5772 bitmap_set_bit (e1
, SSA_NAME_VERSION (n1
));
5773 bitmap_set_bit (e2
, SSA_NAME_VERSION (n2
));
5775 /* If the equivalence sets have a common intersection, then the two
5776 names can be compared without checking their ranges. */
5777 if (bitmap_intersect_p (e1
, e2
))
5779 bitmap_clear_bit (e1
, SSA_NAME_VERSION (n1
));
5780 bitmap_clear_bit (e2
, SSA_NAME_VERSION (n2
));
5782 return (comp
== EQ_EXPR
|| comp
== GE_EXPR
|| comp
== LE_EXPR
)
5784 : boolean_false_node
;
5787 /* Start at -1. Set it to 0 if we do a comparison without relying
5788 on overflow, or 1 if all comparisons rely on overflow. */
5789 used_strict_overflow
= -1;
5791 /* Otherwise, compare all the equivalent ranges. First, add N1 and
5792 N2 to their own set of equivalences to avoid duplicating the body
5793 of the loop just to check N1 and N2 ranges. */
5794 EXECUTE_IF_SET_IN_BITMAP (e1
, 0, i1
, bi1
)
5796 value_range_t vr1
= get_vr_for_comparison (i1
);
5798 t
= retval
= NULL_TREE
;
5799 EXECUTE_IF_SET_IN_BITMAP (e2
, 0, i2
, bi2
)
5803 value_range_t vr2
= get_vr_for_comparison (i2
);
5805 t
= compare_ranges (comp
, &vr1
, &vr2
, &sop
);
5808 /* If we get different answers from different members
5809 of the equivalence set this check must be in a dead
5810 code region. Folding it to a trap representation
5811 would be correct here. For now just return don't-know. */
5815 bitmap_clear_bit (e1
, SSA_NAME_VERSION (n1
));
5816 bitmap_clear_bit (e2
, SSA_NAME_VERSION (n2
));
5822 used_strict_overflow
= 0;
5823 else if (used_strict_overflow
< 0)
5824 used_strict_overflow
= 1;
5830 bitmap_clear_bit (e1
, SSA_NAME_VERSION (n1
));
5831 bitmap_clear_bit (e2
, SSA_NAME_VERSION (n2
));
5832 if (used_strict_overflow
> 0)
5833 *strict_overflow_p
= true;
5838 /* None of the equivalent ranges are useful in computing this
5840 bitmap_clear_bit (e1
, SSA_NAME_VERSION (n1
));
5841 bitmap_clear_bit (e2
, SSA_NAME_VERSION (n2
));
5845 /* Helper function for vrp_evaluate_conditional_warnv. */
5848 vrp_evaluate_conditional_warnv_with_ops_using_ranges (enum tree_code code
,
5850 bool * strict_overflow_p
)
5852 value_range_t
*vr0
, *vr1
;
5854 vr0
= (TREE_CODE (op0
) == SSA_NAME
) ? get_value_range (op0
) : NULL
;
5855 vr1
= (TREE_CODE (op1
) == SSA_NAME
) ? get_value_range (op1
) : NULL
;
5858 return compare_ranges (code
, vr0
, vr1
, strict_overflow_p
);
5859 else if (vr0
&& vr1
== NULL
)
5860 return compare_range_with_value (code
, vr0
, op1
, strict_overflow_p
);
5861 else if (vr0
== NULL
&& vr1
)
5862 return (compare_range_with_value
5863 (swap_tree_comparison (code
), vr1
, op0
, strict_overflow_p
));
5867 /* Helper function for vrp_evaluate_conditional_warnv. */
5870 vrp_evaluate_conditional_warnv_with_ops (enum tree_code code
, tree op0
,
5871 tree op1
, bool use_equiv_p
,
5872 bool *strict_overflow_p
, bool *only_ranges
)
5876 *only_ranges
= true;
5878 /* We only deal with integral and pointer types. */
5879 if (!INTEGRAL_TYPE_P (TREE_TYPE (op0
))
5880 && !POINTER_TYPE_P (TREE_TYPE (op0
)))
5886 && (ret
= vrp_evaluate_conditional_warnv_with_ops_using_ranges
5887 (code
, op0
, op1
, strict_overflow_p
)))
5889 *only_ranges
= false;
5890 if (TREE_CODE (op0
) == SSA_NAME
&& TREE_CODE (op1
) == SSA_NAME
)
5891 return compare_names (code
, op0
, op1
, strict_overflow_p
);
5892 else if (TREE_CODE (op0
) == SSA_NAME
)
5893 return compare_name_with_value (code
, op0
, op1
, strict_overflow_p
);
5894 else if (TREE_CODE (op1
) == SSA_NAME
)
5895 return (compare_name_with_value
5896 (swap_tree_comparison (code
), op1
, op0
, strict_overflow_p
));
5899 return vrp_evaluate_conditional_warnv_with_ops_using_ranges (code
, op0
, op1
,
5904 /* Given (CODE OP0 OP1) within STMT, try to simplify it based on value range
5905 information. Return NULL if the conditional can not be evaluated.
5906 The ranges of all the names equivalent with the operands in COND
5907 will be used when trying to compute the value. If the result is
5908 based on undefined signed overflow, issue a warning if
5912 vrp_evaluate_conditional (enum tree_code code
, tree op0
, tree op1
, gimple stmt
)
5918 /* Some passes and foldings leak constants with overflow flag set
5919 into the IL. Avoid doing wrong things with these and bail out. */
5920 if ((TREE_CODE (op0
) == INTEGER_CST
5921 && TREE_OVERFLOW (op0
))
5922 || (TREE_CODE (op1
) == INTEGER_CST
5923 && TREE_OVERFLOW (op1
)))
5927 ret
= vrp_evaluate_conditional_warnv_with_ops (code
, op0
, op1
, true, &sop
,
5932 enum warn_strict_overflow_code wc
;
5933 const char* warnmsg
;
5935 if (is_gimple_min_invariant (ret
))
5937 wc
= WARN_STRICT_OVERFLOW_CONDITIONAL
;
5938 warnmsg
= G_("assuming signed overflow does not occur when "
5939 "simplifying conditional to constant");
5943 wc
= WARN_STRICT_OVERFLOW_COMPARISON
;
5944 warnmsg
= G_("assuming signed overflow does not occur when "
5945 "simplifying conditional");
5948 if (issue_strict_overflow_warning (wc
))
5950 location_t location
;
5952 if (!gimple_has_location (stmt
))
5953 location
= input_location
;
5955 location
= gimple_location (stmt
);
5956 warning_at (location
, OPT_Wstrict_overflow
, "%s", warnmsg
);
5960 if (warn_type_limits
5961 && ret
&& only_ranges
5962 && TREE_CODE_CLASS (code
) == tcc_comparison
5963 && TREE_CODE (op0
) == SSA_NAME
)
5965 /* If the comparison is being folded and the operand on the LHS
5966 is being compared against a constant value that is outside of
5967 the natural range of OP0's type, then the predicate will
5968 always fold regardless of the value of OP0. If -Wtype-limits
5969 was specified, emit a warning. */
5970 tree type
= TREE_TYPE (op0
);
5971 value_range_t
*vr0
= get_value_range (op0
);
5973 if (vr0
->type
!= VR_VARYING
5974 && INTEGRAL_TYPE_P (type
)
5975 && vrp_val_is_min (vr0
->min
)
5976 && vrp_val_is_max (vr0
->max
)
5977 && is_gimple_min_invariant (op1
))
5979 location_t location
;
5981 if (!gimple_has_location (stmt
))
5982 location
= input_location
;
5984 location
= gimple_location (stmt
);
5986 warning_at (location
, OPT_Wtype_limits
,
5988 ? G_("comparison always false "
5989 "due to limited range of data type")
5990 : G_("comparison always true "
5991 "due to limited range of data type"));
5999 /* Visit conditional statement STMT. If we can determine which edge
6000 will be taken out of STMT's basic block, record it in
6001 *TAKEN_EDGE_P and return SSA_PROP_INTERESTING. Otherwise, return
6002 SSA_PROP_VARYING. */
6004 static enum ssa_prop_result
6005 vrp_visit_cond_stmt (gimple stmt
, edge
*taken_edge_p
)
6010 *taken_edge_p
= NULL
;
6012 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
6017 fprintf (dump_file
, "\nVisiting conditional with predicate: ");
6018 print_gimple_stmt (dump_file
, stmt
, 0, 0);
6019 fprintf (dump_file
, "\nWith known ranges\n");
6021 FOR_EACH_SSA_TREE_OPERAND (use
, stmt
, i
, SSA_OP_USE
)
6023 fprintf (dump_file
, "\t");
6024 print_generic_expr (dump_file
, use
, 0);
6025 fprintf (dump_file
, ": ");
6026 dump_value_range (dump_file
, vr_value
[SSA_NAME_VERSION (use
)]);
6029 fprintf (dump_file
, "\n");
6032 /* Compute the value of the predicate COND by checking the known
6033 ranges of each of its operands.
6035 Note that we cannot evaluate all the equivalent ranges here
6036 because those ranges may not yet be final and with the current
6037 propagation strategy, we cannot determine when the value ranges
6038 of the names in the equivalence set have changed.
6040 For instance, given the following code fragment
6044 i_14 = ASSERT_EXPR <i_5, i_5 != 0>
6048 Assume that on the first visit to i_14, i_5 has the temporary
6049 range [8, 8] because the second argument to the PHI function is
6050 not yet executable. We derive the range ~[0, 0] for i_14 and the
6051 equivalence set { i_5 }. So, when we visit 'if (i_14 == 1)' for
6052 the first time, since i_14 is equivalent to the range [8, 8], we
6053 determine that the predicate is always false.
6055 On the next round of propagation, i_13 is determined to be
6056 VARYING, which causes i_5 to drop down to VARYING. So, another
6057 visit to i_14 is scheduled. In this second visit, we compute the
6058 exact same range and equivalence set for i_14, namely ~[0, 0] and
6059 { i_5 }. But we did not have the previous range for i_5
6060 registered, so vrp_visit_assignment thinks that the range for
6061 i_14 has not changed. Therefore, the predicate 'if (i_14 == 1)'
6062 is not visited again, which stops propagation from visiting
6063 statements in the THEN clause of that if().
6065 To properly fix this we would need to keep the previous range
6066 value for the names in the equivalence set. This way we would've
6067 discovered that from one visit to the other i_5 changed from
6068 range [8, 8] to VR_VARYING.
6070 However, fixing this apparent limitation may not be worth the
6071 additional checking. Testing on several code bases (GCC, DLV,
6072 MICO, TRAMP3D and SPEC2000) showed that doing this results in
6073 4 more predicates folded in SPEC. */
6076 val
= vrp_evaluate_conditional_warnv_with_ops (gimple_cond_code (stmt
),
6077 gimple_cond_lhs (stmt
),
6078 gimple_cond_rhs (stmt
),
6083 *taken_edge_p
= find_taken_edge (gimple_bb (stmt
), val
);
6086 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
6088 "\nIgnoring predicate evaluation because "
6089 "it assumes that signed overflow is undefined");
6094 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
6096 fprintf (dump_file
, "\nPredicate evaluates to: ");
6097 if (val
== NULL_TREE
)
6098 fprintf (dump_file
, "DON'T KNOW\n");
6100 print_generic_stmt (dump_file
, val
, 0);
6103 return (*taken_edge_p
) ? SSA_PROP_INTERESTING
: SSA_PROP_VARYING
;
6106 /* Searches the case label vector VEC for the index *IDX of the CASE_LABEL
6107 that includes the value VAL. The search is restricted to the range
6108 [START_IDX, n - 1] where n is the size of VEC.
6110 If there is a CASE_LABEL for VAL, its index is placed in IDX and true is
6113 If there is no CASE_LABEL for VAL and there is one that is larger than VAL,
6114 it is placed in IDX and false is returned.
6116 If VAL is larger than any CASE_LABEL, n is placed on IDX and false is
6120 find_case_label_index (gimple stmt
, size_t start_idx
, tree val
, size_t *idx
)
6122 size_t n
= gimple_switch_num_labels (stmt
);
6125 /* Find case label for minimum of the value range or the next one.
6126 At each iteration we are searching in [low, high - 1]. */
6128 for (low
= start_idx
, high
= n
; high
!= low
; )
6132 /* Note that i != high, so we never ask for n. */
6133 size_t i
= (high
+ low
) / 2;
6134 t
= gimple_switch_label (stmt
, i
);
6136 /* Cache the result of comparing CASE_LOW and val. */
6137 cmp
= tree_int_cst_compare (CASE_LOW (t
), val
);
6141 /* Ranges cannot be empty. */
6150 if (CASE_HIGH (t
) != NULL
6151 && tree_int_cst_compare (CASE_HIGH (t
), val
) >= 0)
6163 /* Searches the case label vector VEC for the range of CASE_LABELs that is used
6164 for values between MIN and MAX. The first index is placed in MIN_IDX. The
6165 last index is placed in MAX_IDX. If the range of CASE_LABELs is empty
6166 then MAX_IDX < MIN_IDX.
6167 Returns true if the default label is not needed. */
6170 find_case_label_range (gimple stmt
, tree min
, tree max
, size_t *min_idx
,
6174 bool min_take_default
= !find_case_label_index (stmt
, 1, min
, &i
);
6175 bool max_take_default
= !find_case_label_index (stmt
, i
, max
, &j
);
6179 && max_take_default
)
6181 /* Only the default case label reached.
6182 Return an empty range. */
6189 bool take_default
= min_take_default
|| max_take_default
;
6193 if (max_take_default
)
6196 /* If the case label range is continuous, we do not need
6197 the default case label. Verify that. */
6198 high
= CASE_LOW (gimple_switch_label (stmt
, i
));
6199 if (CASE_HIGH (gimple_switch_label (stmt
, i
)))
6200 high
= CASE_HIGH (gimple_switch_label (stmt
, i
));
6201 for (k
= i
+ 1; k
<= j
; ++k
)
6203 low
= CASE_LOW (gimple_switch_label (stmt
, k
));
6204 if (!integer_onep (int_const_binop (MINUS_EXPR
, low
, high
)))
6206 take_default
= true;
6210 if (CASE_HIGH (gimple_switch_label (stmt
, k
)))
6211 high
= CASE_HIGH (gimple_switch_label (stmt
, k
));
6216 return !take_default
;
6220 /* Visit switch statement STMT. If we can determine which edge
6221 will be taken out of STMT's basic block, record it in
6222 *TAKEN_EDGE_P and return SSA_PROP_INTERESTING. Otherwise, return
6223 SSA_PROP_VARYING. */
6225 static enum ssa_prop_result
6226 vrp_visit_switch_stmt (gimple stmt
, edge
*taken_edge_p
)
6230 size_t i
= 0, j
= 0;
6233 *taken_edge_p
= NULL
;
6234 op
= gimple_switch_index (stmt
);
6235 if (TREE_CODE (op
) != SSA_NAME
)
6236 return SSA_PROP_VARYING
;
6238 vr
= get_value_range (op
);
6239 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
6241 fprintf (dump_file
, "\nVisiting switch expression with operand ");
6242 print_generic_expr (dump_file
, op
, 0);
6243 fprintf (dump_file
, " with known range ");
6244 dump_value_range (dump_file
, vr
);
6245 fprintf (dump_file
, "\n");
6248 if (vr
->type
!= VR_RANGE
6249 || symbolic_range_p (vr
))
6250 return SSA_PROP_VARYING
;
6252 /* Find the single edge that is taken from the switch expression. */
6253 take_default
= !find_case_label_range (stmt
, vr
->min
, vr
->max
, &i
, &j
);
6255 /* Check if the range spans no CASE_LABEL. If so, we only reach the default
6259 gcc_assert (take_default
);
6260 val
= gimple_switch_default_label (stmt
);
6264 /* Check if labels with index i to j and maybe the default label
6265 are all reaching the same label. */
6267 val
= gimple_switch_label (stmt
, i
);
6269 && CASE_LABEL (gimple_switch_default_label (stmt
))
6270 != CASE_LABEL (val
))
6272 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
6273 fprintf (dump_file
, " not a single destination for this "
6275 return SSA_PROP_VARYING
;
6277 for (++i
; i
<= j
; ++i
)
6279 if (CASE_LABEL (gimple_switch_label (stmt
, i
)) != CASE_LABEL (val
))
6281 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
6282 fprintf (dump_file
, " not a single destination for this "
6284 return SSA_PROP_VARYING
;
6289 *taken_edge_p
= find_edge (gimple_bb (stmt
),
6290 label_to_block (CASE_LABEL (val
)));
6292 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
6294 fprintf (dump_file
, " will take edge to ");
6295 print_generic_stmt (dump_file
, CASE_LABEL (val
), 0);
6298 return SSA_PROP_INTERESTING
;
6302 /* Evaluate statement STMT. If the statement produces a useful range,
6303 return SSA_PROP_INTERESTING and record the SSA name with the
6304 interesting range into *OUTPUT_P.
6306 If STMT is a conditional branch and we can determine its truth
6307 value, the taken edge is recorded in *TAKEN_EDGE_P.
6309 If STMT produces a varying value, return SSA_PROP_VARYING. */
6311 static enum ssa_prop_result
6312 vrp_visit_stmt (gimple stmt
, edge
*taken_edge_p
, tree
*output_p
)
6317 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
6319 fprintf (dump_file
, "\nVisiting statement:\n");
6320 print_gimple_stmt (dump_file
, stmt
, 0, dump_flags
);
6321 fprintf (dump_file
, "\n");
6324 if (!stmt_interesting_for_vrp (stmt
))
6325 gcc_assert (stmt_ends_bb_p (stmt
));
6326 else if (is_gimple_assign (stmt
) || is_gimple_call (stmt
))
6328 /* In general, assignments with virtual operands are not useful
6329 for deriving ranges, with the obvious exception of calls to
6330 builtin functions. */
6331 if ((is_gimple_call (stmt
)
6332 && gimple_call_fndecl (stmt
) != NULL_TREE
6333 && DECL_BUILT_IN (gimple_call_fndecl (stmt
)))
6334 || !gimple_vuse (stmt
))
6335 return vrp_visit_assignment_or_call (stmt
, output_p
);
6337 else if (gimple_code (stmt
) == GIMPLE_COND
)
6338 return vrp_visit_cond_stmt (stmt
, taken_edge_p
);
6339 else if (gimple_code (stmt
) == GIMPLE_SWITCH
)
6340 return vrp_visit_switch_stmt (stmt
, taken_edge_p
);
6342 /* All other statements produce nothing of interest for VRP, so mark
6343 their outputs varying and prevent further simulation. */
6344 FOR_EACH_SSA_TREE_OPERAND (def
, stmt
, iter
, SSA_OP_DEF
)
6345 set_value_range_to_varying (get_value_range (def
));
6347 return SSA_PROP_VARYING
;
6351 /* Meet operation for value ranges. Given two value ranges VR0 and
6352 VR1, store in VR0 a range that contains both VR0 and VR1. This
6353 may not be the smallest possible such range. */
6356 vrp_meet (value_range_t
*vr0
, value_range_t
*vr1
)
6358 if (vr0
->type
== VR_UNDEFINED
)
6360 copy_value_range (vr0
, vr1
);
6364 if (vr1
->type
== VR_UNDEFINED
)
6366 /* Nothing to do. VR0 already has the resulting range. */
6370 if (vr0
->type
== VR_VARYING
)
6372 /* Nothing to do. VR0 already has the resulting range. */
6376 if (vr1
->type
== VR_VARYING
)
6378 set_value_range_to_varying (vr0
);
6382 if (vr0
->type
== VR_RANGE
&& vr1
->type
== VR_RANGE
)
6387 /* Compute the convex hull of the ranges. The lower limit of
6388 the new range is the minimum of the two ranges. If they
6389 cannot be compared, then give up. */
6390 cmp
= compare_values (vr0
->min
, vr1
->min
);
6391 if (cmp
== 0 || cmp
== 1)
6398 /* Similarly, the upper limit of the new range is the maximum
6399 of the two ranges. If they cannot be compared, then
6401 cmp
= compare_values (vr0
->max
, vr1
->max
);
6402 if (cmp
== 0 || cmp
== -1)
6409 /* Check for useless ranges. */
6410 if (INTEGRAL_TYPE_P (TREE_TYPE (min
))
6411 && ((vrp_val_is_min (min
) || is_overflow_infinity (min
))
6412 && (vrp_val_is_max (max
) || is_overflow_infinity (max
))))
6415 /* The resulting set of equivalences is the intersection of
6417 if (vr0
->equiv
&& vr1
->equiv
&& vr0
->equiv
!= vr1
->equiv
)
6418 bitmap_and_into (vr0
->equiv
, vr1
->equiv
);
6419 else if (vr0
->equiv
&& !vr1
->equiv
)
6420 bitmap_clear (vr0
->equiv
);
6422 set_value_range (vr0
, vr0
->type
, min
, max
, vr0
->equiv
);
6424 else if (vr0
->type
== VR_ANTI_RANGE
&& vr1
->type
== VR_ANTI_RANGE
)
6426 /* Two anti-ranges meet only if their complements intersect.
6427 Only handle the case of identical ranges. */
6428 if (compare_values (vr0
->min
, vr1
->min
) == 0
6429 && compare_values (vr0
->max
, vr1
->max
) == 0
6430 && compare_values (vr0
->min
, vr0
->max
) == 0)
6432 /* The resulting set of equivalences is the intersection of
6434 if (vr0
->equiv
&& vr1
->equiv
&& vr0
->equiv
!= vr1
->equiv
)
6435 bitmap_and_into (vr0
->equiv
, vr1
->equiv
);
6436 else if (vr0
->equiv
&& !vr1
->equiv
)
6437 bitmap_clear (vr0
->equiv
);
6442 else if (vr0
->type
== VR_ANTI_RANGE
|| vr1
->type
== VR_ANTI_RANGE
)
6444 /* For a numeric range [VAL1, VAL2] and an anti-range ~[VAL3, VAL4],
6445 only handle the case where the ranges have an empty intersection.
6446 The result of the meet operation is the anti-range. */
6447 if (!symbolic_range_p (vr0
)
6448 && !symbolic_range_p (vr1
)
6449 && !value_ranges_intersect_p (vr0
, vr1
))
6451 /* Copy most of VR1 into VR0. Don't copy VR1's equivalence
6452 set. We need to compute the intersection of the two
6453 equivalence sets. */
6454 if (vr1
->type
== VR_ANTI_RANGE
)
6455 set_value_range (vr0
, vr1
->type
, vr1
->min
, vr1
->max
, vr0
->equiv
);
6457 /* The resulting set of equivalences is the intersection of
6459 if (vr0
->equiv
&& vr1
->equiv
&& vr0
->equiv
!= vr1
->equiv
)
6460 bitmap_and_into (vr0
->equiv
, vr1
->equiv
);
6461 else if (vr0
->equiv
&& !vr1
->equiv
)
6462 bitmap_clear (vr0
->equiv
);
6473 /* Failed to find an efficient meet. Before giving up and setting
6474 the result to VARYING, see if we can at least derive a useful
6475 anti-range. FIXME, all this nonsense about distinguishing
6476 anti-ranges from ranges is necessary because of the odd
6477 semantics of range_includes_zero_p and friends. */
6478 if (!symbolic_range_p (vr0
)
6479 && ((vr0
->type
== VR_RANGE
&& !range_includes_zero_p (vr0
))
6480 || (vr0
->type
== VR_ANTI_RANGE
&& range_includes_zero_p (vr0
)))
6481 && !symbolic_range_p (vr1
)
6482 && ((vr1
->type
== VR_RANGE
&& !range_includes_zero_p (vr1
))
6483 || (vr1
->type
== VR_ANTI_RANGE
&& range_includes_zero_p (vr1
))))
6485 set_value_range_to_nonnull (vr0
, TREE_TYPE (vr0
->min
));
6487 /* Since this meet operation did not result from the meeting of
6488 two equivalent names, VR0 cannot have any equivalences. */
6490 bitmap_clear (vr0
->equiv
);
6493 set_value_range_to_varying (vr0
);
6497 /* Visit all arguments for PHI node PHI that flow through executable
6498 edges. If a valid value range can be derived from all the incoming
6499 value ranges, set a new range for the LHS of PHI. */
6501 static enum ssa_prop_result
6502 vrp_visit_phi_node (gimple phi
)
6505 tree lhs
= PHI_RESULT (phi
);
6506 value_range_t
*lhs_vr
= get_value_range (lhs
);
6507 value_range_t vr_result
= { VR_UNDEFINED
, NULL_TREE
, NULL_TREE
, NULL
};
6508 int edges
, old_edges
;
6511 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
6513 fprintf (dump_file
, "\nVisiting PHI node: ");
6514 print_gimple_stmt (dump_file
, phi
, 0, dump_flags
);
6518 for (i
= 0; i
< gimple_phi_num_args (phi
); i
++)
6520 edge e
= gimple_phi_arg_edge (phi
, i
);
6522 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
6525 "\n Argument #%d (%d -> %d %sexecutable)\n",
6526 (int) i
, e
->src
->index
, e
->dest
->index
,
6527 (e
->flags
& EDGE_EXECUTABLE
) ? "" : "not ");
6530 if (e
->flags
& EDGE_EXECUTABLE
)
6532 tree arg
= PHI_ARG_DEF (phi
, i
);
6533 value_range_t vr_arg
;
6537 if (TREE_CODE (arg
) == SSA_NAME
)
6539 vr_arg
= *(get_value_range (arg
));
6543 if (is_overflow_infinity (arg
))
6545 arg
= copy_node (arg
);
6546 TREE_OVERFLOW (arg
) = 0;
6549 vr_arg
.type
= VR_RANGE
;
6552 vr_arg
.equiv
= NULL
;
6555 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
6557 fprintf (dump_file
, "\t");
6558 print_generic_expr (dump_file
, arg
, dump_flags
);
6559 fprintf (dump_file
, "\n\tValue: ");
6560 dump_value_range (dump_file
, &vr_arg
);
6561 fprintf (dump_file
, "\n");
6564 vrp_meet (&vr_result
, &vr_arg
);
6566 if (vr_result
.type
== VR_VARYING
)
6571 if (vr_result
.type
== VR_VARYING
)
6573 else if (vr_result
.type
== VR_UNDEFINED
)
6576 old_edges
= vr_phi_edge_counts
[SSA_NAME_VERSION (lhs
)];
6577 vr_phi_edge_counts
[SSA_NAME_VERSION (lhs
)] = edges
;
6579 /* To prevent infinite iterations in the algorithm, derive ranges
6580 when the new value is slightly bigger or smaller than the
6581 previous one. We don't do this if we have seen a new executable
6582 edge; this helps us avoid an overflow infinity for conditionals
6583 which are not in a loop. */
6585 && gimple_phi_num_args (phi
) > 1
6586 && edges
== old_edges
)
6588 int cmp_min
= compare_values (lhs_vr
->min
, vr_result
.min
);
6589 int cmp_max
= compare_values (lhs_vr
->max
, vr_result
.max
);
6591 /* For non VR_RANGE or for pointers fall back to varying if
6592 the range changed. */
6593 if ((lhs_vr
->type
!= VR_RANGE
|| vr_result
.type
!= VR_RANGE
6594 || POINTER_TYPE_P (TREE_TYPE (lhs
)))
6595 && (cmp_min
!= 0 || cmp_max
!= 0))
6598 /* If the new minimum is smaller or larger than the previous
6599 one, go all the way to -INF. In the first case, to avoid
6600 iterating millions of times to reach -INF, and in the
6601 other case to avoid infinite bouncing between different
6603 if (cmp_min
> 0 || cmp_min
< 0)
6605 if (!needs_overflow_infinity (TREE_TYPE (vr_result
.min
))
6606 || !vrp_var_may_overflow (lhs
, phi
))
6607 vr_result
.min
= TYPE_MIN_VALUE (TREE_TYPE (vr_result
.min
));
6608 else if (supports_overflow_infinity (TREE_TYPE (vr_result
.min
)))
6610 negative_overflow_infinity (TREE_TYPE (vr_result
.min
));
6613 /* Similarly, if the new maximum is smaller or larger than
6614 the previous one, go all the way to +INF. */
6615 if (cmp_max
< 0 || cmp_max
> 0)
6617 if (!needs_overflow_infinity (TREE_TYPE (vr_result
.max
))
6618 || !vrp_var_may_overflow (lhs
, phi
))
6619 vr_result
.max
= TYPE_MAX_VALUE (TREE_TYPE (vr_result
.max
));
6620 else if (supports_overflow_infinity (TREE_TYPE (vr_result
.max
)))
6622 positive_overflow_infinity (TREE_TYPE (vr_result
.max
));
6625 /* If we dropped either bound to +-INF then if this is a loop
6626 PHI node SCEV may known more about its value-range. */
6627 if ((cmp_min
> 0 || cmp_min
< 0
6628 || cmp_max
< 0 || cmp_max
> 0)
6630 && (l
= loop_containing_stmt (phi
))
6631 && l
->header
== gimple_bb (phi
))
6632 adjust_range_with_scev (&vr_result
, l
, phi
, lhs
);
6634 /* If we will end up with a (-INF, +INF) range, set it to
6635 VARYING. Same if the previous max value was invalid for
6636 the type and we end up with vr_result.min > vr_result.max. */
6637 if ((vrp_val_is_max (vr_result
.max
)
6638 && vrp_val_is_min (vr_result
.min
))
6639 || compare_values (vr_result
.min
,
6644 /* If the new range is different than the previous value, keep
6647 if (update_value_range (lhs
, &vr_result
))
6649 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
6651 fprintf (dump_file
, "Found new range for ");
6652 print_generic_expr (dump_file
, lhs
, 0);
6653 fprintf (dump_file
, ": ");
6654 dump_value_range (dump_file
, &vr_result
);
6655 fprintf (dump_file
, "\n\n");
6658 return SSA_PROP_INTERESTING
;
6661 /* Nothing changed, don't add outgoing edges. */
6662 return SSA_PROP_NOT_INTERESTING
;
6664 /* No match found. Set the LHS to VARYING. */
6666 set_value_range_to_varying (lhs_vr
);
6667 return SSA_PROP_VARYING
;
6670 /* Simplify boolean operations if the source is known
6671 to be already a boolean. */
6673 simplify_truth_ops_using_ranges (gimple_stmt_iterator
*gsi
, gimple stmt
)
6675 enum tree_code rhs_code
= gimple_assign_rhs_code (stmt
);
6677 bool need_conversion
;
6679 /* We handle only !=/== case here. */
6680 gcc_assert (rhs_code
== EQ_EXPR
|| rhs_code
== NE_EXPR
);
6682 op0
= gimple_assign_rhs1 (stmt
);
6683 if (!op_with_boolean_value_range_p (op0
))
6686 op1
= gimple_assign_rhs2 (stmt
);
6687 if (!op_with_boolean_value_range_p (op1
))
6690 /* Reduce number of cases to handle to NE_EXPR. As there is no
6691 BIT_XNOR_EXPR we cannot replace A == B with a single statement. */
6692 if (rhs_code
== EQ_EXPR
)
6694 if (TREE_CODE (op1
) == INTEGER_CST
)
6695 op1
= int_const_binop (BIT_XOR_EXPR
, op1
, integer_one_node
);
6700 lhs
= gimple_assign_lhs (stmt
);
6702 = !useless_type_conversion_p (TREE_TYPE (lhs
), TREE_TYPE (op0
));
6704 /* Make sure to not sign-extend a 1-bit 1 when converting the result. */
6706 && !TYPE_UNSIGNED (TREE_TYPE (op0
))
6707 && TYPE_PRECISION (TREE_TYPE (op0
)) == 1
6708 && TYPE_PRECISION (TREE_TYPE (lhs
)) > 1)
6711 /* For A != 0 we can substitute A itself. */
6712 if (integer_zerop (op1
))
6713 gimple_assign_set_rhs_with_ops (gsi
,
6715 ? NOP_EXPR
: TREE_CODE (op0
),
6717 /* For A != B we substitute A ^ B. Either with conversion. */
6718 else if (need_conversion
)
6721 tree tem
= create_tmp_reg (TREE_TYPE (op0
), NULL
);
6722 newop
= gimple_build_assign_with_ops (BIT_XOR_EXPR
, tem
, op0
, op1
);
6723 tem
= make_ssa_name (tem
, newop
);
6724 gimple_assign_set_lhs (newop
, tem
);
6725 gsi_insert_before (gsi
, newop
, GSI_SAME_STMT
);
6726 update_stmt (newop
);
6727 gimple_assign_set_rhs_with_ops (gsi
, NOP_EXPR
, tem
, NULL_TREE
);
6731 gimple_assign_set_rhs_with_ops (gsi
, BIT_XOR_EXPR
, op0
, op1
);
6732 update_stmt (gsi_stmt (*gsi
));
6737 /* Simplify a division or modulo operator to a right shift or
6738 bitwise and if the first operand is unsigned or is greater
6739 than zero and the second operand is an exact power of two. */
6742 simplify_div_or_mod_using_ranges (gimple stmt
)
6744 enum tree_code rhs_code
= gimple_assign_rhs_code (stmt
);
6746 tree op0
= gimple_assign_rhs1 (stmt
);
6747 tree op1
= gimple_assign_rhs2 (stmt
);
6748 value_range_t
*vr
= get_value_range (gimple_assign_rhs1 (stmt
));
6750 if (TYPE_UNSIGNED (TREE_TYPE (op0
)))
6752 val
= integer_one_node
;
6758 val
= compare_range_with_value (GE_EXPR
, vr
, integer_zero_node
, &sop
);
6762 && integer_onep (val
)
6763 && issue_strict_overflow_warning (WARN_STRICT_OVERFLOW_MISC
))
6765 location_t location
;
6767 if (!gimple_has_location (stmt
))
6768 location
= input_location
;
6770 location
= gimple_location (stmt
);
6771 warning_at (location
, OPT_Wstrict_overflow
,
6772 "assuming signed overflow does not occur when "
6773 "simplifying %</%> or %<%%%> to %<>>%> or %<&%>");
6777 if (val
&& integer_onep (val
))
6781 if (rhs_code
== TRUNC_DIV_EXPR
)
6783 t
= build_int_cst (integer_type_node
, tree_log2 (op1
));
6784 gimple_assign_set_rhs_code (stmt
, RSHIFT_EXPR
);
6785 gimple_assign_set_rhs1 (stmt
, op0
);
6786 gimple_assign_set_rhs2 (stmt
, t
);
6790 t
= build_int_cst (TREE_TYPE (op1
), 1);
6791 t
= int_const_binop (MINUS_EXPR
, op1
, t
);
6792 t
= fold_convert (TREE_TYPE (op0
), t
);
6794 gimple_assign_set_rhs_code (stmt
, BIT_AND_EXPR
);
6795 gimple_assign_set_rhs1 (stmt
, op0
);
6796 gimple_assign_set_rhs2 (stmt
, t
);
6806 /* If the operand to an ABS_EXPR is >= 0, then eliminate the
6807 ABS_EXPR. If the operand is <= 0, then simplify the
6808 ABS_EXPR into a NEGATE_EXPR. */
6811 simplify_abs_using_ranges (gimple stmt
)
6814 tree op
= gimple_assign_rhs1 (stmt
);
6815 tree type
= TREE_TYPE (op
);
6816 value_range_t
*vr
= get_value_range (op
);
6818 if (TYPE_UNSIGNED (type
))
6820 val
= integer_zero_node
;
6826 val
= compare_range_with_value (LE_EXPR
, vr
, integer_zero_node
, &sop
);
6830 val
= compare_range_with_value (GE_EXPR
, vr
, integer_zero_node
,
6835 if (integer_zerop (val
))
6836 val
= integer_one_node
;
6837 else if (integer_onep (val
))
6838 val
= integer_zero_node
;
6843 && (integer_onep (val
) || integer_zerop (val
)))
6845 if (sop
&& issue_strict_overflow_warning (WARN_STRICT_OVERFLOW_MISC
))
6847 location_t location
;
6849 if (!gimple_has_location (stmt
))
6850 location
= input_location
;
6852 location
= gimple_location (stmt
);
6853 warning_at (location
, OPT_Wstrict_overflow
,
6854 "assuming signed overflow does not occur when "
6855 "simplifying %<abs (X)%> to %<X%> or %<-X%>");
6858 gimple_assign_set_rhs1 (stmt
, op
);
6859 if (integer_onep (val
))
6860 gimple_assign_set_rhs_code (stmt
, NEGATE_EXPR
);
6862 gimple_assign_set_rhs_code (stmt
, SSA_NAME
);
6871 /* Optimize away redundant BIT_AND_EXPR and BIT_IOR_EXPR.
6872 If all the bits that are being cleared by & are already
6873 known to be zero from VR, or all the bits that are being
6874 set by | are already known to be one from VR, the bit
6875 operation is redundant. */
6878 simplify_bit_ops_using_ranges (gimple_stmt_iterator
*gsi
, gimple stmt
)
6880 tree op0
= gimple_assign_rhs1 (stmt
);
6881 tree op1
= gimple_assign_rhs2 (stmt
);
6882 tree op
= NULL_TREE
;
6883 value_range_t vr0
= { VR_UNDEFINED
, NULL_TREE
, NULL_TREE
, NULL
};
6884 value_range_t vr1
= { VR_UNDEFINED
, NULL_TREE
, NULL_TREE
, NULL
};
6885 double_int may_be_nonzero0
, may_be_nonzero1
;
6886 double_int must_be_nonzero0
, must_be_nonzero1
;
6889 if (TREE_CODE (op0
) == SSA_NAME
)
6890 vr0
= *(get_value_range (op0
));
6891 else if (is_gimple_min_invariant (op0
))
6892 set_value_range_to_value (&vr0
, op0
, NULL
);
6896 if (TREE_CODE (op1
) == SSA_NAME
)
6897 vr1
= *(get_value_range (op1
));
6898 else if (is_gimple_min_invariant (op1
))
6899 set_value_range_to_value (&vr1
, op1
, NULL
);
6903 if (!zero_nonzero_bits_from_vr (&vr0
, &may_be_nonzero0
, &must_be_nonzero0
))
6905 if (!zero_nonzero_bits_from_vr (&vr1
, &may_be_nonzero1
, &must_be_nonzero1
))
6908 switch (gimple_assign_rhs_code (stmt
))
6911 mask
= double_int_and_not (may_be_nonzero0
, must_be_nonzero1
);
6912 if (double_int_zero_p (mask
))
6917 mask
= double_int_and_not (may_be_nonzero1
, must_be_nonzero0
);
6918 if (double_int_zero_p (mask
))
6925 mask
= double_int_and_not (may_be_nonzero0
, must_be_nonzero1
);
6926 if (double_int_zero_p (mask
))
6931 mask
= double_int_and_not (may_be_nonzero1
, must_be_nonzero0
);
6932 if (double_int_zero_p (mask
))
6942 if (op
== NULL_TREE
)
6945 gimple_assign_set_rhs_with_ops (gsi
, TREE_CODE (op
), op
, NULL
);
6946 update_stmt (gsi_stmt (*gsi
));
6950 /* We are comparing trees OP0 and OP1 using COND_CODE. OP0 has
6951 a known value range VR.
6953 If there is one and only one value which will satisfy the
6954 conditional, then return that value. Else return NULL. */
6957 test_for_singularity (enum tree_code cond_code
, tree op0
,
6958 tree op1
, value_range_t
*vr
)
6963 /* Extract minimum/maximum values which satisfy the
6964 the conditional as it was written. */
6965 if (cond_code
== LE_EXPR
|| cond_code
== LT_EXPR
)
6967 /* This should not be negative infinity; there is no overflow
6969 min
= TYPE_MIN_VALUE (TREE_TYPE (op0
));
6972 if (cond_code
== LT_EXPR
&& !is_overflow_infinity (max
))
6974 tree one
= build_int_cst (TREE_TYPE (op0
), 1);
6975 max
= fold_build2 (MINUS_EXPR
, TREE_TYPE (op0
), max
, one
);
6977 TREE_NO_WARNING (max
) = 1;
6980 else if (cond_code
== GE_EXPR
|| cond_code
== GT_EXPR
)
6982 /* This should not be positive infinity; there is no overflow
6984 max
= TYPE_MAX_VALUE (TREE_TYPE (op0
));
6987 if (cond_code
== GT_EXPR
&& !is_overflow_infinity (min
))
6989 tree one
= build_int_cst (TREE_TYPE (op0
), 1);
6990 min
= fold_build2 (PLUS_EXPR
, TREE_TYPE (op0
), min
, one
);
6992 TREE_NO_WARNING (min
) = 1;
6996 /* Now refine the minimum and maximum values using any
6997 value range information we have for op0. */
7000 if (compare_values (vr
->min
, min
) == 1)
7002 if (compare_values (vr
->max
, max
) == -1)
7005 /* If the new min/max values have converged to a single value,
7006 then there is only one value which can satisfy the condition,
7007 return that value. */
7008 if (operand_equal_p (min
, max
, 0) && is_gimple_min_invariant (min
))
7014 /* Simplify a conditional using a relational operator to an equality
7015 test if the range information indicates only one value can satisfy
7016 the original conditional. */
7019 simplify_cond_using_ranges (gimple stmt
)
7021 tree op0
= gimple_cond_lhs (stmt
);
7022 tree op1
= gimple_cond_rhs (stmt
);
7023 enum tree_code cond_code
= gimple_cond_code (stmt
);
7025 if (cond_code
!= NE_EXPR
7026 && cond_code
!= EQ_EXPR
7027 && TREE_CODE (op0
) == SSA_NAME
7028 && INTEGRAL_TYPE_P (TREE_TYPE (op0
))
7029 && is_gimple_min_invariant (op1
))
7031 value_range_t
*vr
= get_value_range (op0
);
7033 /* If we have range information for OP0, then we might be
7034 able to simplify this conditional. */
7035 if (vr
->type
== VR_RANGE
)
7037 tree new_tree
= test_for_singularity (cond_code
, op0
, op1
, vr
);
7043 fprintf (dump_file
, "Simplified relational ");
7044 print_gimple_stmt (dump_file
, stmt
, 0, 0);
7045 fprintf (dump_file
, " into ");
7048 gimple_cond_set_code (stmt
, EQ_EXPR
);
7049 gimple_cond_set_lhs (stmt
, op0
);
7050 gimple_cond_set_rhs (stmt
, new_tree
);
7056 print_gimple_stmt (dump_file
, stmt
, 0, 0);
7057 fprintf (dump_file
, "\n");
7063 /* Try again after inverting the condition. We only deal
7064 with integral types here, so no need to worry about
7065 issues with inverting FP comparisons. */
7066 cond_code
= invert_tree_comparison (cond_code
, false);
7067 new_tree
= test_for_singularity (cond_code
, op0
, op1
, vr
);
7073 fprintf (dump_file
, "Simplified relational ");
7074 print_gimple_stmt (dump_file
, stmt
, 0, 0);
7075 fprintf (dump_file
, " into ");
7078 gimple_cond_set_code (stmt
, NE_EXPR
);
7079 gimple_cond_set_lhs (stmt
, op0
);
7080 gimple_cond_set_rhs (stmt
, new_tree
);
7086 print_gimple_stmt (dump_file
, stmt
, 0, 0);
7087 fprintf (dump_file
, "\n");
7098 /* Simplify a switch statement using the value range of the switch
7102 simplify_switch_using_ranges (gimple stmt
)
7104 tree op
= gimple_switch_index (stmt
);
7109 size_t i
= 0, j
= 0, n
, n2
;
7113 if (TREE_CODE (op
) == SSA_NAME
)
7115 vr
= get_value_range (op
);
7117 /* We can only handle integer ranges. */
7118 if (vr
->type
!= VR_RANGE
7119 || symbolic_range_p (vr
))
7122 /* Find case label for min/max of the value range. */
7123 take_default
= !find_case_label_range (stmt
, vr
->min
, vr
->max
, &i
, &j
);
7125 else if (TREE_CODE (op
) == INTEGER_CST
)
7127 take_default
= !find_case_label_index (stmt
, 1, op
, &i
);
7141 n
= gimple_switch_num_labels (stmt
);
7143 /* Bail out if this is just all edges taken. */
7149 /* Build a new vector of taken case labels. */
7150 vec2
= make_tree_vec (j
- i
+ 1 + (int)take_default
);
7153 /* Add the default edge, if necessary. */
7155 TREE_VEC_ELT (vec2
, n2
++) = gimple_switch_default_label (stmt
);
7157 for (; i
<= j
; ++i
, ++n2
)
7158 TREE_VEC_ELT (vec2
, n2
) = gimple_switch_label (stmt
, i
);
7160 /* Mark needed edges. */
7161 for (i
= 0; i
< n2
; ++i
)
7163 e
= find_edge (gimple_bb (stmt
),
7164 label_to_block (CASE_LABEL (TREE_VEC_ELT (vec2
, i
))));
7165 e
->aux
= (void *)-1;
7168 /* Queue not needed edges for later removal. */
7169 FOR_EACH_EDGE (e
, ei
, gimple_bb (stmt
)->succs
)
7171 if (e
->aux
== (void *)-1)
7177 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
7179 fprintf (dump_file
, "removing unreachable case label\n");
7181 VEC_safe_push (edge
, heap
, to_remove_edges
, e
);
7182 e
->flags
&= ~EDGE_EXECUTABLE
;
7185 /* And queue an update for the stmt. */
7188 VEC_safe_push (switch_update
, heap
, to_update_switch_stmts
, &su
);
7192 /* Simplify an integral conversion from an SSA name in STMT. */
7195 simplify_conversion_using_ranges (gimple stmt
)
7197 tree innerop
, middleop
, finaltype
;
7199 value_range_t
*innervr
;
7200 double_int innermin
, innermax
, middlemin
, middlemax
;
7202 finaltype
= TREE_TYPE (gimple_assign_lhs (stmt
));
7203 if (!INTEGRAL_TYPE_P (finaltype
))
7205 middleop
= gimple_assign_rhs1 (stmt
);
7206 def_stmt
= SSA_NAME_DEF_STMT (middleop
);
7207 if (!is_gimple_assign (def_stmt
)
7208 || !CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (def_stmt
)))
7210 innerop
= gimple_assign_rhs1 (def_stmt
);
7211 if (TREE_CODE (innerop
) != SSA_NAME
)
7214 /* Get the value-range of the inner operand. */
7215 innervr
= get_value_range (innerop
);
7216 if (innervr
->type
!= VR_RANGE
7217 || TREE_CODE (innervr
->min
) != INTEGER_CST
7218 || TREE_CODE (innervr
->max
) != INTEGER_CST
)
7221 /* Simulate the conversion chain to check if the result is equal if
7222 the middle conversion is removed. */
7223 innermin
= tree_to_double_int (innervr
->min
);
7224 innermax
= tree_to_double_int (innervr
->max
);
7225 middlemin
= double_int_ext (innermin
, TYPE_PRECISION (TREE_TYPE (middleop
)),
7226 TYPE_UNSIGNED (TREE_TYPE (middleop
)));
7227 middlemax
= double_int_ext (innermax
, TYPE_PRECISION (TREE_TYPE (middleop
)),
7228 TYPE_UNSIGNED (TREE_TYPE (middleop
)));
7229 /* If the middle values do not represent a proper range fail. */
7230 if (double_int_cmp (middlemin
, middlemax
,
7231 TYPE_UNSIGNED (TREE_TYPE (middleop
))) > 0)
7233 if (!double_int_equal_p (double_int_ext (middlemin
,
7234 TYPE_PRECISION (finaltype
),
7235 TYPE_UNSIGNED (finaltype
)),
7236 double_int_ext (innermin
,
7237 TYPE_PRECISION (finaltype
),
7238 TYPE_UNSIGNED (finaltype
)))
7239 || !double_int_equal_p (double_int_ext (middlemax
,
7240 TYPE_PRECISION (finaltype
),
7241 TYPE_UNSIGNED (finaltype
)),
7242 double_int_ext (innermax
,
7243 TYPE_PRECISION (finaltype
),
7244 TYPE_UNSIGNED (finaltype
))))
7247 gimple_assign_set_rhs1 (stmt
, innerop
);
7252 /* Return whether the value range *VR fits in an integer type specified
7253 by PRECISION and UNSIGNED_P. */
7256 range_fits_type_p (value_range_t
*vr
, unsigned precision
, bool unsigned_p
)
7259 unsigned src_precision
;
7262 /* We can only handle integral and pointer types. */
7263 src_type
= TREE_TYPE (vr
->min
);
7264 if (!INTEGRAL_TYPE_P (src_type
)
7265 && !POINTER_TYPE_P (src_type
))
7268 /* An extension is always fine, so is an identity transform. */
7269 src_precision
= TYPE_PRECISION (TREE_TYPE (vr
->min
));
7270 if (src_precision
< precision
7271 || (src_precision
== precision
7272 && TYPE_UNSIGNED (src_type
) == unsigned_p
))
7275 /* Now we can only handle ranges with constant bounds. */
7276 if (vr
->type
!= VR_RANGE
7277 || TREE_CODE (vr
->min
) != INTEGER_CST
7278 || TREE_CODE (vr
->max
) != INTEGER_CST
)
7281 /* For precision-preserving sign-changes the MSB of the double-int
7283 if (src_precision
== precision
7284 && (TREE_INT_CST_HIGH (vr
->min
) | TREE_INT_CST_HIGH (vr
->max
)) < 0)
7287 /* Then we can perform the conversion on both ends and compare
7288 the result for equality. */
7289 tem
= double_int_ext (tree_to_double_int (vr
->min
), precision
, unsigned_p
);
7290 if (!double_int_equal_p (tree_to_double_int (vr
->min
), tem
))
7292 tem
= double_int_ext (tree_to_double_int (vr
->max
), precision
, unsigned_p
);
7293 if (!double_int_equal_p (tree_to_double_int (vr
->max
), tem
))
7299 /* Simplify a conversion from integral SSA name to float in STMT. */
7302 simplify_float_conversion_using_ranges (gimple_stmt_iterator
*gsi
, gimple stmt
)
7304 tree rhs1
= gimple_assign_rhs1 (stmt
);
7305 value_range_t
*vr
= get_value_range (rhs1
);
7306 enum machine_mode fltmode
= TYPE_MODE (TREE_TYPE (gimple_assign_lhs (stmt
)));
7307 enum machine_mode mode
;
7311 /* We can only handle constant ranges. */
7312 if (vr
->type
!= VR_RANGE
7313 || TREE_CODE (vr
->min
) != INTEGER_CST
7314 || TREE_CODE (vr
->max
) != INTEGER_CST
)
7317 /* First check if we can use a signed type in place of an unsigned. */
7318 if (TYPE_UNSIGNED (TREE_TYPE (rhs1
))
7319 && (can_float_p (fltmode
, TYPE_MODE (TREE_TYPE (rhs1
)), 0)
7320 != CODE_FOR_nothing
)
7321 && range_fits_type_p (vr
, GET_MODE_PRECISION
7322 (TYPE_MODE (TREE_TYPE (rhs1
))), 0))
7323 mode
= TYPE_MODE (TREE_TYPE (rhs1
));
7324 /* If we can do the conversion in the current input mode do nothing. */
7325 else if (can_float_p (fltmode
, TYPE_MODE (TREE_TYPE (rhs1
)),
7326 TYPE_UNSIGNED (TREE_TYPE (rhs1
))))
7328 /* Otherwise search for a mode we can use, starting from the narrowest
7329 integer mode available. */
7332 mode
= GET_CLASS_NARROWEST_MODE (MODE_INT
);
7335 /* If we cannot do a signed conversion to float from mode
7336 or if the value-range does not fit in the signed type
7337 try with a wider mode. */
7338 if (can_float_p (fltmode
, mode
, 0) != CODE_FOR_nothing
7339 && range_fits_type_p (vr
, GET_MODE_PRECISION (mode
), 0))
7342 mode
= GET_MODE_WIDER_MODE (mode
);
7343 /* But do not widen the input. Instead leave that to the
7344 optabs expansion code. */
7345 if (GET_MODE_PRECISION (mode
) > TYPE_PRECISION (TREE_TYPE (rhs1
)))
7348 while (mode
!= VOIDmode
);
7349 if (mode
== VOIDmode
)
7353 /* It works, insert a truncation or sign-change before the
7354 float conversion. */
7355 tem
= create_tmp_var (build_nonstandard_integer_type
7356 (GET_MODE_PRECISION (mode
), 0), NULL
);
7357 conv
= gimple_build_assign_with_ops (NOP_EXPR
, tem
, rhs1
, NULL_TREE
);
7358 tem
= make_ssa_name (tem
, conv
);
7359 gimple_assign_set_lhs (conv
, tem
);
7360 gsi_insert_before (gsi
, conv
, GSI_SAME_STMT
);
7361 gimple_assign_set_rhs1 (stmt
, tem
);
7367 /* Simplify STMT using ranges if possible. */
7370 simplify_stmt_using_ranges (gimple_stmt_iterator
*gsi
)
7372 gimple stmt
= gsi_stmt (*gsi
);
7373 if (is_gimple_assign (stmt
))
7375 enum tree_code rhs_code
= gimple_assign_rhs_code (stmt
);
7376 tree rhs1
= gimple_assign_rhs1 (stmt
);
7382 /* Transform EQ_EXPR, NE_EXPR into BIT_XOR_EXPR or identity
7383 if the RHS is zero or one, and the LHS are known to be boolean
7385 if (INTEGRAL_TYPE_P (TREE_TYPE (rhs1
)))
7386 return simplify_truth_ops_using_ranges (gsi
, stmt
);
7389 /* Transform TRUNC_DIV_EXPR and TRUNC_MOD_EXPR into RSHIFT_EXPR
7390 and BIT_AND_EXPR respectively if the first operand is greater
7391 than zero and the second operand is an exact power of two. */
7392 case TRUNC_DIV_EXPR
:
7393 case TRUNC_MOD_EXPR
:
7394 if (INTEGRAL_TYPE_P (TREE_TYPE (rhs1
))
7395 && integer_pow2p (gimple_assign_rhs2 (stmt
)))
7396 return simplify_div_or_mod_using_ranges (stmt
);
7399 /* Transform ABS (X) into X or -X as appropriate. */
7401 if (TREE_CODE (rhs1
) == SSA_NAME
7402 && INTEGRAL_TYPE_P (TREE_TYPE (rhs1
)))
7403 return simplify_abs_using_ranges (stmt
);
7408 /* Optimize away BIT_AND_EXPR and BIT_IOR_EXPR
7409 if all the bits being cleared are already cleared or
7410 all the bits being set are already set. */
7411 if (INTEGRAL_TYPE_P (TREE_TYPE (rhs1
)))
7412 return simplify_bit_ops_using_ranges (gsi
, stmt
);
7416 if (TREE_CODE (rhs1
) == SSA_NAME
7417 && INTEGRAL_TYPE_P (TREE_TYPE (rhs1
)))
7418 return simplify_conversion_using_ranges (stmt
);
7422 if (TREE_CODE (rhs1
) == SSA_NAME
7423 && INTEGRAL_TYPE_P (TREE_TYPE (rhs1
)))
7424 return simplify_float_conversion_using_ranges (gsi
, stmt
);
7431 else if (gimple_code (stmt
) == GIMPLE_COND
)
7432 return simplify_cond_using_ranges (stmt
);
7433 else if (gimple_code (stmt
) == GIMPLE_SWITCH
)
7434 return simplify_switch_using_ranges (stmt
);
7439 /* If the statement pointed by SI has a predicate whose value can be
7440 computed using the value range information computed by VRP, compute
7441 its value and return true. Otherwise, return false. */
7444 fold_predicate_in (gimple_stmt_iterator
*si
)
7446 bool assignment_p
= false;
7448 gimple stmt
= gsi_stmt (*si
);
7450 if (is_gimple_assign (stmt
)
7451 && TREE_CODE_CLASS (gimple_assign_rhs_code (stmt
)) == tcc_comparison
)
7453 assignment_p
= true;
7454 val
= vrp_evaluate_conditional (gimple_assign_rhs_code (stmt
),
7455 gimple_assign_rhs1 (stmt
),
7456 gimple_assign_rhs2 (stmt
),
7459 else if (gimple_code (stmt
) == GIMPLE_COND
)
7460 val
= vrp_evaluate_conditional (gimple_cond_code (stmt
),
7461 gimple_cond_lhs (stmt
),
7462 gimple_cond_rhs (stmt
),
7470 val
= fold_convert (gimple_expr_type (stmt
), val
);
7474 fprintf (dump_file
, "Folding predicate ");
7475 print_gimple_expr (dump_file
, stmt
, 0, 0);
7476 fprintf (dump_file
, " to ");
7477 print_generic_expr (dump_file
, val
, 0);
7478 fprintf (dump_file
, "\n");
7481 if (is_gimple_assign (stmt
))
7482 gimple_assign_set_rhs_from_tree (si
, val
);
7485 gcc_assert (gimple_code (stmt
) == GIMPLE_COND
);
7486 if (integer_zerop (val
))
7487 gimple_cond_make_false (stmt
);
7488 else if (integer_onep (val
))
7489 gimple_cond_make_true (stmt
);
7500 /* Callback for substitute_and_fold folding the stmt at *SI. */
7503 vrp_fold_stmt (gimple_stmt_iterator
*si
)
7505 if (fold_predicate_in (si
))
7508 return simplify_stmt_using_ranges (si
);
7511 /* Stack of dest,src equivalency pairs that need to be restored after
7512 each attempt to thread a block's incoming edge to an outgoing edge.
7514 A NULL entry is used to mark the end of pairs which need to be
7516 static VEC(tree
,heap
) *stack
;
7518 /* A trivial wrapper so that we can present the generic jump threading
7519 code with a simple API for simplifying statements. STMT is the
7520 statement we want to simplify, WITHIN_STMT provides the location
7521 for any overflow warnings. */
7524 simplify_stmt_for_jump_threading (gimple stmt
, gimple within_stmt
)
7526 /* We only use VRP information to simplify conditionals. This is
7527 overly conservative, but it's unclear if doing more would be
7528 worth the compile time cost. */
7529 if (gimple_code (stmt
) != GIMPLE_COND
)
7532 return vrp_evaluate_conditional (gimple_cond_code (stmt
),
7533 gimple_cond_lhs (stmt
),
7534 gimple_cond_rhs (stmt
), within_stmt
);
7537 /* Blocks which have more than one predecessor and more than
7538 one successor present jump threading opportunities, i.e.,
7539 when the block is reached from a specific predecessor, we
7540 may be able to determine which of the outgoing edges will
7541 be traversed. When this optimization applies, we are able
7542 to avoid conditionals at runtime and we may expose secondary
7543 optimization opportunities.
7545 This routine is effectively a driver for the generic jump
7546 threading code. It basically just presents the generic code
7547 with edges that may be suitable for jump threading.
7549 Unlike DOM, we do not iterate VRP if jump threading was successful.
7550 While iterating may expose new opportunities for VRP, it is expected
7551 those opportunities would be very limited and the compile time cost
7552 to expose those opportunities would be significant.
7554 As jump threading opportunities are discovered, they are registered
7555 for later realization. */
7558 identify_jump_threads (void)
7565 /* Ugh. When substituting values earlier in this pass we can
7566 wipe the dominance information. So rebuild the dominator
7567 information as we need it within the jump threading code. */
7568 calculate_dominance_info (CDI_DOMINATORS
);
7570 /* We do not allow VRP information to be used for jump threading
7571 across a back edge in the CFG. Otherwise it becomes too
7572 difficult to avoid eliminating loop exit tests. Of course
7573 EDGE_DFS_BACK is not accurate at this time so we have to
7575 mark_dfs_back_edges ();
7577 /* Do not thread across edges we are about to remove. Just marking
7578 them as EDGE_DFS_BACK will do. */
7579 FOR_EACH_VEC_ELT (edge
, to_remove_edges
, i
, e
)
7580 e
->flags
|= EDGE_DFS_BACK
;
7582 /* Allocate our unwinder stack to unwind any temporary equivalences
7583 that might be recorded. */
7584 stack
= VEC_alloc (tree
, heap
, 20);
7586 /* To avoid lots of silly node creation, we create a single
7587 conditional and just modify it in-place when attempting to
7589 dummy
= gimple_build_cond (EQ_EXPR
,
7590 integer_zero_node
, integer_zero_node
,
7593 /* Walk through all the blocks finding those which present a
7594 potential jump threading opportunity. We could set this up
7595 as a dominator walker and record data during the walk, but
7596 I doubt it's worth the effort for the classes of jump
7597 threading opportunities we are trying to identify at this
7598 point in compilation. */
7603 /* If the generic jump threading code does not find this block
7604 interesting, then there is nothing to do. */
7605 if (! potentially_threadable_block (bb
))
7608 /* We only care about blocks ending in a COND_EXPR. While there
7609 may be some value in handling SWITCH_EXPR here, I doubt it's
7610 terribly important. */
7611 last
= gsi_stmt (gsi_last_bb (bb
));
7613 /* We're basically looking for a switch or any kind of conditional with
7614 integral or pointer type arguments. Note the type of the second
7615 argument will be the same as the first argument, so no need to
7616 check it explicitly. */
7617 if (gimple_code (last
) == GIMPLE_SWITCH
7618 || (gimple_code (last
) == GIMPLE_COND
7619 && TREE_CODE (gimple_cond_lhs (last
)) == SSA_NAME
7620 && (INTEGRAL_TYPE_P (TREE_TYPE (gimple_cond_lhs (last
)))
7621 || POINTER_TYPE_P (TREE_TYPE (gimple_cond_lhs (last
))))
7622 && (TREE_CODE (gimple_cond_rhs (last
)) == SSA_NAME
7623 || is_gimple_min_invariant (gimple_cond_rhs (last
)))))
7627 /* We've got a block with multiple predecessors and multiple
7628 successors which also ends in a suitable conditional or
7629 switch statement. For each predecessor, see if we can thread
7630 it to a specific successor. */
7631 FOR_EACH_EDGE (e
, ei
, bb
->preds
)
7633 /* Do not thread across back edges or abnormal edges
7635 if (e
->flags
& (EDGE_DFS_BACK
| EDGE_COMPLEX
))
7638 thread_across_edge (dummy
, e
, true, &stack
,
7639 simplify_stmt_for_jump_threading
);
7644 /* We do not actually update the CFG or SSA graphs at this point as
7645 ASSERT_EXPRs are still in the IL and cfg cleanup code does not yet
7646 handle ASSERT_EXPRs gracefully. */
7649 /* We identified all the jump threading opportunities earlier, but could
7650 not transform the CFG at that time. This routine transforms the
7651 CFG and arranges for the dominator tree to be rebuilt if necessary.
7653 Note the SSA graph update will occur during the normal TODO
7654 processing by the pass manager. */
7656 finalize_jump_threads (void)
7658 thread_through_all_blocks (false);
7659 VEC_free (tree
, heap
, stack
);
7663 /* Traverse all the blocks folding conditionals with known ranges. */
7670 values_propagated
= true;
7674 fprintf (dump_file
, "\nValue ranges after VRP:\n\n");
7675 dump_all_value_ranges (dump_file
);
7676 fprintf (dump_file
, "\n");
7679 substitute_and_fold (op_with_constant_singleton_value_range
,
7680 vrp_fold_stmt
, false);
7682 if (warn_array_bounds
)
7683 check_all_array_refs ();
7685 /* We must identify jump threading opportunities before we release
7686 the datastructures built by VRP. */
7687 identify_jump_threads ();
7689 /* Free allocated memory. */
7690 for (i
= 0; i
< num_vr_values
; i
++)
7693 BITMAP_FREE (vr_value
[i
]->equiv
);
7698 free (vr_phi_edge_counts
);
7700 /* So that we can distinguish between VRP data being available
7701 and not available. */
7703 vr_phi_edge_counts
= NULL
;
7707 /* Main entry point to VRP (Value Range Propagation). This pass is
7708 loosely based on J. R. C. Patterson, ``Accurate Static Branch
7709 Prediction by Value Range Propagation,'' in SIGPLAN Conference on
7710 Programming Language Design and Implementation, pp. 67-78, 1995.
7711 Also available at http://citeseer.ist.psu.edu/patterson95accurate.html
7713 This is essentially an SSA-CCP pass modified to deal with ranges
7714 instead of constants.
7716 While propagating ranges, we may find that two or more SSA name
7717 have equivalent, though distinct ranges. For instance,
7720 2 p_4 = ASSERT_EXPR <p_3, p_3 != 0>
7722 4 p_5 = ASSERT_EXPR <p_4, p_4 == q_2>;
7726 In the code above, pointer p_5 has range [q_2, q_2], but from the
7727 code we can also determine that p_5 cannot be NULL and, if q_2 had
7728 a non-varying range, p_5's range should also be compatible with it.
7730 These equivalences are created by two expressions: ASSERT_EXPR and
7731 copy operations. Since p_5 is an assertion on p_4, and p_4 was the
7732 result of another assertion, then we can use the fact that p_5 and
7733 p_4 are equivalent when evaluating p_5's range.
7735 Together with value ranges, we also propagate these equivalences
7736 between names so that we can take advantage of information from
7737 multiple ranges when doing final replacement. Note that this
7738 equivalency relation is transitive but not symmetric.
7740 In the example above, p_5 is equivalent to p_4, q_2 and p_3, but we
7741 cannot assert that q_2 is equivalent to p_5 because q_2 may be used
7742 in contexts where that assertion does not hold (e.g., in line 6).
7744 TODO, the main difference between this pass and Patterson's is that
7745 we do not propagate edge probabilities. We only compute whether
7746 edges can be taken or not. That is, instead of having a spectrum
7747 of jump probabilities between 0 and 1, we only deal with 0, 1 and
7748 DON'T KNOW. In the future, it may be worthwhile to propagate
7749 probabilities to aid branch prediction. */
7758 loop_optimizer_init (LOOPS_NORMAL
| LOOPS_HAVE_RECORDED_EXITS
);
7759 rewrite_into_loop_closed_ssa (NULL
, TODO_update_ssa
);
7762 insert_range_assertions ();
7764 /* Estimate number of iterations - but do not use undefined behavior
7765 for this. We can't do this lazily as other functions may compute
7766 this using undefined behavior. */
7767 free_numbers_of_iterations_estimates ();
7768 estimate_numbers_of_iterations (false);
7770 to_remove_edges
= VEC_alloc (edge
, heap
, 10);
7771 to_update_switch_stmts
= VEC_alloc (switch_update
, heap
, 5);
7772 threadedge_initialize_values ();
7775 ssa_propagate (vrp_visit_stmt
, vrp_visit_phi_node
);
7778 free_numbers_of_iterations_estimates ();
7780 /* ASSERT_EXPRs must be removed before finalizing jump threads
7781 as finalizing jump threads calls the CFG cleanup code which
7782 does not properly handle ASSERT_EXPRs. */
7783 remove_range_assertions ();
7785 /* If we exposed any new variables, go ahead and put them into
7786 SSA form now, before we handle jump threading. This simplifies
7787 interactions between rewriting of _DECL nodes into SSA form
7788 and rewriting SSA_NAME nodes into SSA form after block
7789 duplication and CFG manipulation. */
7790 update_ssa (TODO_update_ssa
);
7792 finalize_jump_threads ();
7794 /* Remove dead edges from SWITCH_EXPR optimization. This leaves the
7795 CFG in a broken state and requires a cfg_cleanup run. */
7796 FOR_EACH_VEC_ELT (edge
, to_remove_edges
, i
, e
)
7798 /* Update SWITCH_EXPR case label vector. */
7799 FOR_EACH_VEC_ELT (switch_update
, to_update_switch_stmts
, i
, su
)
7802 size_t n
= TREE_VEC_LENGTH (su
->vec
);
7804 gimple_switch_set_num_labels (su
->stmt
, n
);
7805 for (j
= 0; j
< n
; j
++)
7806 gimple_switch_set_label (su
->stmt
, j
, TREE_VEC_ELT (su
->vec
, j
));
7807 /* As we may have replaced the default label with a regular one
7808 make sure to make it a real default label again. This ensures
7809 optimal expansion. */
7810 label
= gimple_switch_default_label (su
->stmt
);
7811 CASE_LOW (label
) = NULL_TREE
;
7812 CASE_HIGH (label
) = NULL_TREE
;
7815 if (VEC_length (edge
, to_remove_edges
) > 0)
7816 free_dominance_info (CDI_DOMINATORS
);
7818 VEC_free (edge
, heap
, to_remove_edges
);
7819 VEC_free (switch_update
, heap
, to_update_switch_stmts
);
7820 threadedge_finalize_values ();
7823 loop_optimizer_finalize ();
7830 return flag_tree_vrp
!= 0;
7833 struct gimple_opt_pass pass_vrp
=
7838 gate_vrp
, /* gate */
7839 execute_vrp
, /* execute */
7842 0, /* static_pass_number */
7843 TV_TREE_VRP
, /* tv_id */
7844 PROP_ssa
, /* properties_required */
7845 0, /* properties_provided */
7846 0, /* properties_destroyed */
7847 0, /* todo_flags_start */
7852 | TODO_ggc_collect
/* todo_flags_finish */