1 /* Support routines for Value Range Propagation (VRP).
2 Copyright (C) 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012
3 Free Software Foundation, Inc.
4 Contributed by Diego Novillo <dnovillo@redhat.com>.
6 This file is part of GCC.
8 GCC is free software; you can redistribute it and/or modify
9 it under the terms of the GNU General Public License as published by
10 the Free Software Foundation; either version 3, or (at your option)
13 GCC is distributed in the hope that it will be useful,
14 but WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 GNU General Public License for more details.
18 You should have received a copy of the GNU General Public License
19 along with GCC; see the file COPYING3. If not see
20 <http://www.gnu.org/licenses/>. */
24 #include "coretypes.h"
29 #include "basic-block.h"
30 #include "tree-flow.h"
31 #include "tree-pass.h"
32 #include "tree-dump.h"
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 (var
);
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 if (TYPE_PRECISION (TREE_TYPE (max
)) == 1
1697 && !TYPE_UNSIGNED (TREE_TYPE (max
)))
1698 max
= fold_build2 (PLUS_EXPR
, TREE_TYPE (max
), max
,
1699 build_int_cst (TREE_TYPE (max
), -1));
1701 max
= fold_build2 (MINUS_EXPR
, TREE_TYPE (max
), max
,
1702 build_int_cst (TREE_TYPE (max
), 1));
1704 TREE_NO_WARNING (max
) = 1;
1707 set_value_range (vr_p
, VR_RANGE
, min
, max
, vr_p
->equiv
);
1710 else if (cond_code
== GE_EXPR
|| cond_code
== GT_EXPR
)
1712 max
= TYPE_MAX_VALUE (type
);
1714 if (limit_vr
== NULL
|| limit_vr
->type
== VR_ANTI_RANGE
)
1718 /* If LIMIT_VR is of the form [N1, N2], we need to build the
1719 range [N1, MAX] for GE_EXPR and [N1 + 1, MAX] for
1721 min
= limit_vr
->min
;
1724 /* If the minimum value forces us to be out of bounds, simply punt.
1725 It would be pointless to try and do anything more since this
1726 all should be optimized away above us. */
1727 if ((cond_code
== GT_EXPR
1728 && compare_values (min
, max
) == 0)
1729 || (CONSTANT_CLASS_P (min
) && TREE_OVERFLOW (min
)))
1730 set_value_range_to_varying (vr_p
);
1733 /* For GT_EXPR, we create the range [MIN + 1, MAX]. */
1734 if (cond_code
== GT_EXPR
)
1736 if (TYPE_PRECISION (TREE_TYPE (min
)) == 1
1737 && !TYPE_UNSIGNED (TREE_TYPE (min
)))
1738 min
= fold_build2 (MINUS_EXPR
, TREE_TYPE (min
), min
,
1739 build_int_cst (TREE_TYPE (min
), -1));
1741 min
= fold_build2 (PLUS_EXPR
, TREE_TYPE (min
), min
,
1742 build_int_cst (TREE_TYPE (min
), 1));
1744 TREE_NO_WARNING (min
) = 1;
1747 set_value_range (vr_p
, VR_RANGE
, min
, max
, vr_p
->equiv
);
1753 /* If VAR already had a known range, it may happen that the new
1754 range we have computed and VAR's range are not compatible. For
1758 p_6 = ASSERT_EXPR <p_5, p_5 == NULL>;
1760 p_8 = ASSERT_EXPR <p_6, p_6 != NULL>;
1762 While the above comes from a faulty program, it will cause an ICE
1763 later because p_8 and p_6 will have incompatible ranges and at
1764 the same time will be considered equivalent. A similar situation
1768 i_6 = ASSERT_EXPR <i_5, i_5 > 10>;
1770 i_7 = ASSERT_EXPR <i_6, i_6 < 5>;
1772 Again i_6 and i_7 will have incompatible ranges. It would be
1773 pointless to try and do anything with i_7's range because
1774 anything dominated by 'if (i_5 < 5)' will be optimized away.
1775 Note, due to the wa in which simulation proceeds, the statement
1776 i_7 = ASSERT_EXPR <...> we would never be visited because the
1777 conditional 'if (i_5 < 5)' always evaluates to false. However,
1778 this extra check does not hurt and may protect against future
1779 changes to VRP that may get into a situation similar to the
1780 NULL pointer dereference example.
1782 Note that these compatibility tests are only needed when dealing
1783 with ranges or a mix of range and anti-range. If VAR_VR and VR_P
1784 are both anti-ranges, they will always be compatible, because two
1785 anti-ranges will always have a non-empty intersection. */
1787 var_vr
= get_value_range (var
);
1789 /* We may need to make adjustments when VR_P and VAR_VR are numeric
1790 ranges or anti-ranges. */
1791 if (vr_p
->type
== VR_VARYING
1792 || vr_p
->type
== VR_UNDEFINED
1793 || var_vr
->type
== VR_VARYING
1794 || var_vr
->type
== VR_UNDEFINED
1795 || symbolic_range_p (vr_p
)
1796 || symbolic_range_p (var_vr
))
1799 if (var_vr
->type
== VR_RANGE
&& vr_p
->type
== VR_RANGE
)
1801 /* If the two ranges have a non-empty intersection, we can
1802 refine the resulting range. Since the assert expression
1803 creates an equivalency and at the same time it asserts a
1804 predicate, we can take the intersection of the two ranges to
1805 get better precision. */
1806 if (value_ranges_intersect_p (var_vr
, vr_p
))
1808 /* Use the larger of the two minimums. */
1809 if (compare_values (vr_p
->min
, var_vr
->min
) == -1)
1814 /* Use the smaller of the two maximums. */
1815 if (compare_values (vr_p
->max
, var_vr
->max
) == 1)
1820 set_value_range (vr_p
, vr_p
->type
, min
, max
, vr_p
->equiv
);
1824 /* The two ranges do not intersect, set the new range to
1825 VARYING, because we will not be able to do anything
1826 meaningful with it. */
1827 set_value_range_to_varying (vr_p
);
1830 else if ((var_vr
->type
== VR_RANGE
&& vr_p
->type
== VR_ANTI_RANGE
)
1831 || (var_vr
->type
== VR_ANTI_RANGE
&& vr_p
->type
== VR_RANGE
))
1833 /* A range and an anti-range will cancel each other only if
1834 their ends are the same. For instance, in the example above,
1835 p_8's range ~[0, 0] and p_6's range [0, 0] are incompatible,
1836 so VR_P should be set to VR_VARYING. */
1837 if (compare_values (var_vr
->min
, vr_p
->min
) == 0
1838 && compare_values (var_vr
->max
, vr_p
->max
) == 0)
1839 set_value_range_to_varying (vr_p
);
1842 tree min
, max
, anti_min
, anti_max
, real_min
, real_max
;
1845 /* We want to compute the logical AND of the two ranges;
1846 there are three cases to consider.
1849 1. The VR_ANTI_RANGE range is completely within the
1850 VR_RANGE and the endpoints of the ranges are
1851 different. In that case the resulting range
1852 should be whichever range is more precise.
1853 Typically that will be the VR_RANGE.
1855 2. The VR_ANTI_RANGE is completely disjoint from
1856 the VR_RANGE. In this case the resulting range
1857 should be the VR_RANGE.
1859 3. There is some overlap between the VR_ANTI_RANGE
1862 3a. If the high limit of the VR_ANTI_RANGE resides
1863 within the VR_RANGE, then the result is a new
1864 VR_RANGE starting at the high limit of the
1865 VR_ANTI_RANGE + 1 and extending to the
1866 high limit of the original VR_RANGE.
1868 3b. If the low limit of the VR_ANTI_RANGE resides
1869 within the VR_RANGE, then the result is a new
1870 VR_RANGE starting at the low limit of the original
1871 VR_RANGE and extending to the low limit of the
1872 VR_ANTI_RANGE - 1. */
1873 if (vr_p
->type
== VR_ANTI_RANGE
)
1875 anti_min
= vr_p
->min
;
1876 anti_max
= vr_p
->max
;
1877 real_min
= var_vr
->min
;
1878 real_max
= var_vr
->max
;
1882 anti_min
= var_vr
->min
;
1883 anti_max
= var_vr
->max
;
1884 real_min
= vr_p
->min
;
1885 real_max
= vr_p
->max
;
1889 /* Case 1, VR_ANTI_RANGE completely within VR_RANGE,
1890 not including any endpoints. */
1891 if (compare_values (anti_max
, real_max
) == -1
1892 && compare_values (anti_min
, real_min
) == 1)
1894 /* If the range is covering the whole valid range of
1895 the type keep the anti-range. */
1896 if (!vrp_val_is_min (real_min
)
1897 || !vrp_val_is_max (real_max
))
1898 set_value_range (vr_p
, VR_RANGE
, real_min
,
1899 real_max
, vr_p
->equiv
);
1901 /* Case 2, VR_ANTI_RANGE completely disjoint from
1903 else if (compare_values (anti_min
, real_max
) == 1
1904 || compare_values (anti_max
, real_min
) == -1)
1906 set_value_range (vr_p
, VR_RANGE
, real_min
,
1907 real_max
, vr_p
->equiv
);
1909 /* Case 3a, the anti-range extends into the low
1910 part of the real range. Thus creating a new
1911 low for the real range. */
1912 else if (((cmp
= compare_values (anti_max
, real_min
)) == 1
1914 && compare_values (anti_max
, real_max
) == -1)
1916 gcc_assert (!is_positive_overflow_infinity (anti_max
));
1917 if (needs_overflow_infinity (TREE_TYPE (anti_max
))
1918 && vrp_val_is_max (anti_max
))
1920 if (!supports_overflow_infinity (TREE_TYPE (var_vr
->min
)))
1922 set_value_range_to_varying (vr_p
);
1925 min
= positive_overflow_infinity (TREE_TYPE (var_vr
->min
));
1927 else if (!POINTER_TYPE_P (TREE_TYPE (var_vr
->min
)))
1929 if (TYPE_PRECISION (TREE_TYPE (var_vr
->min
)) == 1
1930 && !TYPE_UNSIGNED (TREE_TYPE (var_vr
->min
)))
1931 min
= fold_build2 (MINUS_EXPR
, TREE_TYPE (var_vr
->min
),
1933 build_int_cst (TREE_TYPE (var_vr
->min
),
1936 min
= fold_build2 (PLUS_EXPR
, TREE_TYPE (var_vr
->min
),
1938 build_int_cst (TREE_TYPE (var_vr
->min
),
1942 min
= fold_build_pointer_plus_hwi (anti_max
, 1);
1944 set_value_range (vr_p
, VR_RANGE
, min
, max
, vr_p
->equiv
);
1946 /* Case 3b, the anti-range extends into the high
1947 part of the real range. Thus creating a new
1948 higher for the real range. */
1949 else if (compare_values (anti_min
, real_min
) == 1
1950 && ((cmp
= compare_values (anti_min
, real_max
)) == -1
1953 gcc_assert (!is_negative_overflow_infinity (anti_min
));
1954 if (needs_overflow_infinity (TREE_TYPE (anti_min
))
1955 && vrp_val_is_min (anti_min
))
1957 if (!supports_overflow_infinity (TREE_TYPE (var_vr
->min
)))
1959 set_value_range_to_varying (vr_p
);
1962 max
= negative_overflow_infinity (TREE_TYPE (var_vr
->min
));
1964 else if (!POINTER_TYPE_P (TREE_TYPE (var_vr
->min
)))
1966 if (TYPE_PRECISION (TREE_TYPE (var_vr
->min
)) == 1
1967 && !TYPE_UNSIGNED (TREE_TYPE (var_vr
->min
)))
1968 max
= fold_build2 (PLUS_EXPR
, TREE_TYPE (var_vr
->min
),
1970 build_int_cst (TREE_TYPE (var_vr
->min
),
1973 max
= fold_build2 (MINUS_EXPR
, TREE_TYPE (var_vr
->min
),
1975 build_int_cst (TREE_TYPE (var_vr
->min
),
1979 max
= fold_build_pointer_plus_hwi (anti_min
, -1);
1981 set_value_range (vr_p
, VR_RANGE
, min
, max
, vr_p
->equiv
);
1988 /* Extract range information from SSA name VAR and store it in VR. If
1989 VAR has an interesting range, use it. Otherwise, create the
1990 range [VAR, VAR] and return it. This is useful in situations where
1991 we may have conditionals testing values of VARYING names. For
1998 Even if y_5 is deemed VARYING, we can determine that x_3 > y_5 is
2002 extract_range_from_ssa_name (value_range_t
*vr
, tree var
)
2004 value_range_t
*var_vr
= get_value_range (var
);
2006 if (var_vr
->type
!= VR_UNDEFINED
&& var_vr
->type
!= VR_VARYING
)
2007 copy_value_range (vr
, var_vr
);
2009 set_value_range (vr
, VR_RANGE
, var
, var
, NULL
);
2011 add_equivalence (&vr
->equiv
, var
);
2015 /* Wrapper around int_const_binop. If the operation overflows and we
2016 are not using wrapping arithmetic, then adjust the result to be
2017 -INF or +INF depending on CODE, VAL1 and VAL2. This can return
2018 NULL_TREE if we need to use an overflow infinity representation but
2019 the type does not support it. */
2022 vrp_int_const_binop (enum tree_code code
, tree val1
, tree val2
)
2026 res
= int_const_binop (code
, val1
, val2
);
2028 /* If we are using unsigned arithmetic, operate symbolically
2029 on -INF and +INF as int_const_binop only handles signed overflow. */
2030 if (TYPE_UNSIGNED (TREE_TYPE (val1
)))
2032 int checkz
= compare_values (res
, val1
);
2033 bool overflow
= false;
2035 /* Ensure that res = val1 [+*] val2 >= val1
2036 or that res = val1 - val2 <= val1. */
2037 if ((code
== PLUS_EXPR
2038 && !(checkz
== 1 || checkz
== 0))
2039 || (code
== MINUS_EXPR
2040 && !(checkz
== 0 || checkz
== -1)))
2044 /* Checking for multiplication overflow is done by dividing the
2045 output of the multiplication by the first input of the
2046 multiplication. If the result of that division operation is
2047 not equal to the second input of the multiplication, then the
2048 multiplication overflowed. */
2049 else if (code
== MULT_EXPR
&& !integer_zerop (val1
))
2051 tree tmp
= int_const_binop (TRUNC_DIV_EXPR
,
2054 int check
= compare_values (tmp
, val2
);
2062 res
= copy_node (res
);
2063 TREE_OVERFLOW (res
) = 1;
2067 else if (TYPE_OVERFLOW_WRAPS (TREE_TYPE (val1
)))
2068 /* If the singed operation wraps then int_const_binop has done
2069 everything we want. */
2071 else if ((TREE_OVERFLOW (res
)
2072 && !TREE_OVERFLOW (val1
)
2073 && !TREE_OVERFLOW (val2
))
2074 || is_overflow_infinity (val1
)
2075 || is_overflow_infinity (val2
))
2077 /* If the operation overflowed but neither VAL1 nor VAL2 are
2078 overflown, return -INF or +INF depending on the operation
2079 and the combination of signs of the operands. */
2080 int sgn1
= tree_int_cst_sgn (val1
);
2081 int sgn2
= tree_int_cst_sgn (val2
);
2083 if (needs_overflow_infinity (TREE_TYPE (res
))
2084 && !supports_overflow_infinity (TREE_TYPE (res
)))
2087 /* We have to punt on adding infinities of different signs,
2088 since we can't tell what the sign of the result should be.
2089 Likewise for subtracting infinities of the same sign. */
2090 if (((code
== PLUS_EXPR
&& sgn1
!= sgn2
)
2091 || (code
== MINUS_EXPR
&& sgn1
== sgn2
))
2092 && is_overflow_infinity (val1
)
2093 && is_overflow_infinity (val2
))
2096 /* Don't try to handle division or shifting of infinities. */
2097 if ((code
== TRUNC_DIV_EXPR
2098 || code
== FLOOR_DIV_EXPR
2099 || code
== CEIL_DIV_EXPR
2100 || code
== EXACT_DIV_EXPR
2101 || code
== ROUND_DIV_EXPR
2102 || code
== RSHIFT_EXPR
)
2103 && (is_overflow_infinity (val1
)
2104 || is_overflow_infinity (val2
)))
2107 /* Notice that we only need to handle the restricted set of
2108 operations handled by extract_range_from_binary_expr.
2109 Among them, only multiplication, addition and subtraction
2110 can yield overflow without overflown operands because we
2111 are working with integral types only... except in the
2112 case VAL1 = -INF and VAL2 = -1 which overflows to +INF
2113 for division too. */
2115 /* For multiplication, the sign of the overflow is given
2116 by the comparison of the signs of the operands. */
2117 if ((code
== MULT_EXPR
&& sgn1
== sgn2
)
2118 /* For addition, the operands must be of the same sign
2119 to yield an overflow. Its sign is therefore that
2120 of one of the operands, for example the first. For
2121 infinite operands X + -INF is negative, not positive. */
2122 || (code
== PLUS_EXPR
2124 ? !is_negative_overflow_infinity (val2
)
2125 : is_positive_overflow_infinity (val2
)))
2126 /* For subtraction, non-infinite operands must be of
2127 different signs to yield an overflow. Its sign is
2128 therefore that of the first operand or the opposite of
2129 that of the second operand. A first operand of 0 counts
2130 as positive here, for the corner case 0 - (-INF), which
2131 overflows, but must yield +INF. For infinite operands 0
2132 - INF is negative, not positive. */
2133 || (code
== MINUS_EXPR
2135 ? !is_positive_overflow_infinity (val2
)
2136 : is_negative_overflow_infinity (val2
)))
2137 /* We only get in here with positive shift count, so the
2138 overflow direction is the same as the sign of val1.
2139 Actually rshift does not overflow at all, but we only
2140 handle the case of shifting overflowed -INF and +INF. */
2141 || (code
== RSHIFT_EXPR
2143 /* For division, the only case is -INF / -1 = +INF. */
2144 || code
== TRUNC_DIV_EXPR
2145 || code
== FLOOR_DIV_EXPR
2146 || code
== CEIL_DIV_EXPR
2147 || code
== EXACT_DIV_EXPR
2148 || code
== ROUND_DIV_EXPR
)
2149 return (needs_overflow_infinity (TREE_TYPE (res
))
2150 ? positive_overflow_infinity (TREE_TYPE (res
))
2151 : TYPE_MAX_VALUE (TREE_TYPE (res
)));
2153 return (needs_overflow_infinity (TREE_TYPE (res
))
2154 ? negative_overflow_infinity (TREE_TYPE (res
))
2155 : TYPE_MIN_VALUE (TREE_TYPE (res
)));
2162 /* For range VR compute two double_int bitmasks. In *MAY_BE_NONZERO
2163 bitmask if some bit is unset, it means for all numbers in the range
2164 the bit is 0, otherwise it might be 0 or 1. In *MUST_BE_NONZERO
2165 bitmask if some bit is set, it means for all numbers in the range
2166 the bit is 1, otherwise it might be 0 or 1. */
2169 zero_nonzero_bits_from_vr (value_range_t
*vr
,
2170 double_int
*may_be_nonzero
,
2171 double_int
*must_be_nonzero
)
2173 *may_be_nonzero
= double_int_minus_one
;
2174 *must_be_nonzero
= double_int_zero
;
2175 if (!range_int_cst_p (vr
))
2178 if (range_int_cst_singleton_p (vr
))
2180 *may_be_nonzero
= tree_to_double_int (vr
->min
);
2181 *must_be_nonzero
= *may_be_nonzero
;
2183 else if (tree_int_cst_sgn (vr
->min
) >= 0
2184 || tree_int_cst_sgn (vr
->max
) < 0)
2186 double_int dmin
= tree_to_double_int (vr
->min
);
2187 double_int dmax
= tree_to_double_int (vr
->max
);
2188 double_int xor_mask
= double_int_xor (dmin
, dmax
);
2189 *may_be_nonzero
= double_int_ior (dmin
, dmax
);
2190 *must_be_nonzero
= double_int_and (dmin
, dmax
);
2191 if (xor_mask
.high
!= 0)
2193 unsigned HOST_WIDE_INT mask
2194 = ((unsigned HOST_WIDE_INT
) 1
2195 << floor_log2 (xor_mask
.high
)) - 1;
2196 may_be_nonzero
->low
= ALL_ONES
;
2197 may_be_nonzero
->high
|= mask
;
2198 must_be_nonzero
->low
= 0;
2199 must_be_nonzero
->high
&= ~mask
;
2201 else if (xor_mask
.low
!= 0)
2203 unsigned HOST_WIDE_INT mask
2204 = ((unsigned HOST_WIDE_INT
) 1
2205 << floor_log2 (xor_mask
.low
)) - 1;
2206 may_be_nonzero
->low
|= mask
;
2207 must_be_nonzero
->low
&= ~mask
;
2214 /* Helper to extract a value-range *VR for a multiplicative operation
2218 extract_range_from_multiplicative_op_1 (value_range_t
*vr
,
2219 enum tree_code code
,
2220 value_range_t
*vr0
, value_range_t
*vr1
)
2222 enum value_range_type type
;
2229 /* Multiplications, divisions and shifts are a bit tricky to handle,
2230 depending on the mix of signs we have in the two ranges, we
2231 need to operate on different values to get the minimum and
2232 maximum values for the new range. One approach is to figure
2233 out all the variations of range combinations and do the
2236 However, this involves several calls to compare_values and it
2237 is pretty convoluted. It's simpler to do the 4 operations
2238 (MIN0 OP MIN1, MIN0 OP MAX1, MAX0 OP MIN1 and MAX0 OP MAX0 OP
2239 MAX1) and then figure the smallest and largest values to form
2241 gcc_assert (code
== MULT_EXPR
2242 || code
== TRUNC_DIV_EXPR
2243 || code
== FLOOR_DIV_EXPR
2244 || code
== CEIL_DIV_EXPR
2245 || code
== EXACT_DIV_EXPR
2246 || code
== ROUND_DIV_EXPR
2247 || code
== RSHIFT_EXPR
);
2248 gcc_assert ((vr0
->type
== VR_RANGE
2249 || (code
== MULT_EXPR
&& vr0
->type
== VR_ANTI_RANGE
))
2250 && vr0
->type
== vr1
->type
);
2254 /* Compute the 4 cross operations. */
2256 val
[0] = vrp_int_const_binop (code
, vr0
->min
, vr1
->min
);
2257 if (val
[0] == NULL_TREE
)
2260 if (vr1
->max
== vr1
->min
)
2264 val
[1] = vrp_int_const_binop (code
, vr0
->min
, vr1
->max
);
2265 if (val
[1] == NULL_TREE
)
2269 if (vr0
->max
== vr0
->min
)
2273 val
[2] = vrp_int_const_binop (code
, vr0
->max
, vr1
->min
);
2274 if (val
[2] == NULL_TREE
)
2278 if (vr0
->min
== vr0
->max
|| vr1
->min
== vr1
->max
)
2282 val
[3] = vrp_int_const_binop (code
, vr0
->max
, vr1
->max
);
2283 if (val
[3] == NULL_TREE
)
2289 set_value_range_to_varying (vr
);
2293 /* Set MIN to the minimum of VAL[i] and MAX to the maximum
2297 for (i
= 1; i
< 4; i
++)
2299 if (!is_gimple_min_invariant (min
)
2300 || (TREE_OVERFLOW (min
) && !is_overflow_infinity (min
))
2301 || !is_gimple_min_invariant (max
)
2302 || (TREE_OVERFLOW (max
) && !is_overflow_infinity (max
)))
2307 if (!is_gimple_min_invariant (val
[i
])
2308 || (TREE_OVERFLOW (val
[i
])
2309 && !is_overflow_infinity (val
[i
])))
2311 /* If we found an overflowed value, set MIN and MAX
2312 to it so that we set the resulting range to
2318 if (compare_values (val
[i
], min
) == -1)
2321 if (compare_values (val
[i
], max
) == 1)
2326 /* If either MIN or MAX overflowed, then set the resulting range to
2327 VARYING. But we do accept an overflow infinity
2329 if (min
== NULL_TREE
2330 || !is_gimple_min_invariant (min
)
2331 || (TREE_OVERFLOW (min
) && !is_overflow_infinity (min
))
2333 || !is_gimple_min_invariant (max
)
2334 || (TREE_OVERFLOW (max
) && !is_overflow_infinity (max
)))
2336 set_value_range_to_varying (vr
);
2342 2) [-INF, +-INF(OVF)]
2343 3) [+-INF(OVF), +INF]
2344 4) [+-INF(OVF), +-INF(OVF)]
2345 We learn nothing when we have INF and INF(OVF) on both sides.
2346 Note that we do accept [-INF, -INF] and [+INF, +INF] without
2348 if ((vrp_val_is_min (min
) || is_overflow_infinity (min
))
2349 && (vrp_val_is_max (max
) || is_overflow_infinity (max
)))
2351 set_value_range_to_varying (vr
);
2355 cmp
= compare_values (min
, max
);
2356 if (cmp
== -2 || cmp
== 1)
2358 /* If the new range has its limits swapped around (MIN > MAX),
2359 then the operation caused one of them to wrap around, mark
2360 the new range VARYING. */
2361 set_value_range_to_varying (vr
);
2364 set_value_range (vr
, type
, min
, max
, NULL
);
2367 /* Extract range information from a binary operation CODE based on
2368 the ranges of each of its operands, *VR0 and *VR1 with resulting
2369 type EXPR_TYPE. The resulting range is stored in *VR. */
2372 extract_range_from_binary_expr_1 (value_range_t
*vr
,
2373 enum tree_code code
, tree expr_type
,
2374 value_range_t
*vr0_
, value_range_t
*vr1_
)
2376 value_range_t vr0
= *vr0_
, vr1
= *vr1_
;
2377 enum value_range_type type
;
2378 tree min
= NULL_TREE
, max
= NULL_TREE
;
2381 if (!INTEGRAL_TYPE_P (expr_type
)
2382 && !POINTER_TYPE_P (expr_type
))
2384 set_value_range_to_varying (vr
);
2388 /* Not all binary expressions can be applied to ranges in a
2389 meaningful way. Handle only arithmetic operations. */
2390 if (code
!= PLUS_EXPR
2391 && code
!= MINUS_EXPR
2392 && code
!= POINTER_PLUS_EXPR
2393 && code
!= MULT_EXPR
2394 && code
!= TRUNC_DIV_EXPR
2395 && code
!= FLOOR_DIV_EXPR
2396 && code
!= CEIL_DIV_EXPR
2397 && code
!= EXACT_DIV_EXPR
2398 && code
!= ROUND_DIV_EXPR
2399 && code
!= TRUNC_MOD_EXPR
2400 && code
!= RSHIFT_EXPR
2403 && code
!= BIT_AND_EXPR
2404 && code
!= BIT_IOR_EXPR
2405 && code
!= BIT_XOR_EXPR
)
2407 set_value_range_to_varying (vr
);
2411 /* If both ranges are UNDEFINED, so is the result. */
2412 if (vr0
.type
== VR_UNDEFINED
&& vr1
.type
== VR_UNDEFINED
)
2414 set_value_range_to_undefined (vr
);
2417 /* If one of the ranges is UNDEFINED drop it to VARYING for the following
2418 code. At some point we may want to special-case operations that
2419 have UNDEFINED result for all or some value-ranges of the not UNDEFINED
2421 else if (vr0
.type
== VR_UNDEFINED
)
2422 set_value_range_to_varying (&vr0
);
2423 else if (vr1
.type
== VR_UNDEFINED
)
2424 set_value_range_to_varying (&vr1
);
2426 /* The type of the resulting value range defaults to VR0.TYPE. */
2429 /* Refuse to operate on VARYING ranges, ranges of different kinds
2430 and symbolic ranges. As an exception, we allow BIT_AND_EXPR
2431 because we may be able to derive a useful range even if one of
2432 the operands is VR_VARYING or symbolic range. Similarly for
2433 divisions. TODO, we may be able to derive anti-ranges in
2435 if (code
!= BIT_AND_EXPR
2436 && code
!= BIT_IOR_EXPR
2437 && code
!= TRUNC_DIV_EXPR
2438 && code
!= FLOOR_DIV_EXPR
2439 && code
!= CEIL_DIV_EXPR
2440 && code
!= EXACT_DIV_EXPR
2441 && code
!= ROUND_DIV_EXPR
2442 && code
!= TRUNC_MOD_EXPR
2443 && (vr0
.type
== VR_VARYING
2444 || vr1
.type
== VR_VARYING
2445 || vr0
.type
!= vr1
.type
2446 || symbolic_range_p (&vr0
)
2447 || symbolic_range_p (&vr1
)))
2449 set_value_range_to_varying (vr
);
2453 /* Now evaluate the expression to determine the new range. */
2454 if (POINTER_TYPE_P (expr_type
))
2456 if (code
== MIN_EXPR
|| code
== MAX_EXPR
)
2458 /* For MIN/MAX expressions with pointers, we only care about
2459 nullness, if both are non null, then the result is nonnull.
2460 If both are null, then the result is null. Otherwise they
2462 if (range_is_nonnull (&vr0
) && range_is_nonnull (&vr1
))
2463 set_value_range_to_nonnull (vr
, expr_type
);
2464 else if (range_is_null (&vr0
) && range_is_null (&vr1
))
2465 set_value_range_to_null (vr
, expr_type
);
2467 set_value_range_to_varying (vr
);
2469 else if (code
== POINTER_PLUS_EXPR
)
2471 /* For pointer types, we are really only interested in asserting
2472 whether the expression evaluates to non-NULL. */
2473 if (range_is_nonnull (&vr0
) || range_is_nonnull (&vr1
))
2474 set_value_range_to_nonnull (vr
, expr_type
);
2475 else if (range_is_null (&vr0
) && range_is_null (&vr1
))
2476 set_value_range_to_null (vr
, expr_type
);
2478 set_value_range_to_varying (vr
);
2480 else if (code
== BIT_AND_EXPR
)
2482 /* For pointer types, we are really only interested in asserting
2483 whether the expression evaluates to non-NULL. */
2484 if (range_is_nonnull (&vr0
) && range_is_nonnull (&vr1
))
2485 set_value_range_to_nonnull (vr
, expr_type
);
2486 else if (range_is_null (&vr0
) || range_is_null (&vr1
))
2487 set_value_range_to_null (vr
, expr_type
);
2489 set_value_range_to_varying (vr
);
2492 set_value_range_to_varying (vr
);
2497 /* For integer ranges, apply the operation to each end of the
2498 range and see what we end up with. */
2499 if (code
== PLUS_EXPR
)
2501 /* If we have a PLUS_EXPR with two VR_ANTI_RANGEs, drop to
2502 VR_VARYING. It would take more effort to compute a precise
2503 range for such a case. For example, if we have op0 == 1 and
2504 op1 == -1 with their ranges both being ~[0,0], we would have
2505 op0 + op1 == 0, so we cannot claim that the sum is in ~[0,0].
2506 Note that we are guaranteed to have vr0.type == vr1.type at
2508 if (vr0
.type
== VR_ANTI_RANGE
)
2510 set_value_range_to_varying (vr
);
2514 /* For operations that make the resulting range directly
2515 proportional to the original ranges, apply the operation to
2516 the same end of each range. */
2517 min
= vrp_int_const_binop (code
, vr0
.min
, vr1
.min
);
2518 max
= vrp_int_const_binop (code
, vr0
.max
, vr1
.max
);
2520 /* If both additions overflowed the range kind is still correct.
2521 This happens regularly with subtracting something in unsigned
2523 ??? See PR30318 for all the cases we do not handle. */
2524 if ((TREE_OVERFLOW (min
) && !is_overflow_infinity (min
))
2525 && (TREE_OVERFLOW (max
) && !is_overflow_infinity (max
)))
2527 min
= build_int_cst_wide (TREE_TYPE (min
),
2528 TREE_INT_CST_LOW (min
),
2529 TREE_INT_CST_HIGH (min
));
2530 max
= build_int_cst_wide (TREE_TYPE (max
),
2531 TREE_INT_CST_LOW (max
),
2532 TREE_INT_CST_HIGH (max
));
2535 else if (code
== MIN_EXPR
2536 || code
== MAX_EXPR
)
2538 if (vr0
.type
== VR_ANTI_RANGE
)
2540 /* For MIN_EXPR and MAX_EXPR with two VR_ANTI_RANGEs,
2541 the resulting VR_ANTI_RANGE is the same - intersection
2542 of the two ranges. */
2543 min
= vrp_int_const_binop (MAX_EXPR
, vr0
.min
, vr1
.min
);
2544 max
= vrp_int_const_binop (MIN_EXPR
, vr0
.max
, vr1
.max
);
2548 /* For operations that make the resulting range directly
2549 proportional to the original ranges, apply the operation to
2550 the same end of each range. */
2551 min
= vrp_int_const_binop (code
, vr0
.min
, vr1
.min
);
2552 max
= vrp_int_const_binop (code
, vr0
.max
, vr1
.max
);
2555 else if (code
== MULT_EXPR
)
2557 /* If we have an unsigned MULT_EXPR with two VR_ANTI_RANGEs,
2558 drop to VR_VARYING. It would take more effort to compute a
2559 precise range for such a case. For example, if we have
2560 op0 == 65536 and op1 == 65536 with their ranges both being
2561 ~[0,0] on a 32-bit machine, we would have op0 * op1 == 0, so
2562 we cannot claim that the product is in ~[0,0]. Note that we
2563 are guaranteed to have vr0.type == vr1.type at this
2565 if (vr0
.type
== VR_ANTI_RANGE
2566 && !TYPE_OVERFLOW_UNDEFINED (expr_type
))
2568 set_value_range_to_varying (vr
);
2572 extract_range_from_multiplicative_op_1 (vr
, code
, &vr0
, &vr1
);
2575 else if (code
== RSHIFT_EXPR
)
2577 /* If we have a RSHIFT_EXPR with any shift values outside [0..prec-1],
2578 then drop to VR_VARYING. Outside of this range we get undefined
2579 behavior from the shift operation. We cannot even trust
2580 SHIFT_COUNT_TRUNCATED at this stage, because that applies to rtl
2581 shifts, and the operation at the tree level may be widened. */
2582 if (vr1
.type
!= VR_RANGE
2583 || !value_range_nonnegative_p (&vr1
)
2584 || TREE_CODE (vr1
.max
) != INTEGER_CST
2585 || compare_tree_int (vr1
.max
, TYPE_PRECISION (expr_type
) - 1) == 1)
2587 set_value_range_to_varying (vr
);
2591 extract_range_from_multiplicative_op_1 (vr
, code
, &vr0
, &vr1
);
2594 else if (code
== TRUNC_DIV_EXPR
2595 || code
== FLOOR_DIV_EXPR
2596 || code
== CEIL_DIV_EXPR
2597 || code
== EXACT_DIV_EXPR
2598 || code
== ROUND_DIV_EXPR
)
2600 if (vr0
.type
!= VR_RANGE
|| symbolic_range_p (&vr0
))
2602 /* For division, if op1 has VR_RANGE but op0 does not, something
2603 can be deduced just from that range. Say [min, max] / [4, max]
2604 gives [min / 4, max / 4] range. */
2605 if (vr1
.type
== VR_RANGE
2606 && !symbolic_range_p (&vr1
)
2607 && !range_includes_zero_p (&vr1
))
2609 vr0
.type
= type
= VR_RANGE
;
2610 vr0
.min
= vrp_val_min (expr_type
);
2611 vr0
.max
= vrp_val_max (expr_type
);
2615 set_value_range_to_varying (vr
);
2620 /* For divisions, if flag_non_call_exceptions is true, we must
2621 not eliminate a division by zero. */
2622 if (cfun
->can_throw_non_call_exceptions
2623 && (vr1
.type
!= VR_RANGE
2624 || symbolic_range_p (&vr1
)
2625 || range_includes_zero_p (&vr1
)))
2627 set_value_range_to_varying (vr
);
2631 /* For divisions, if op0 is VR_RANGE, we can deduce a range
2632 even if op1 is VR_VARYING, VR_ANTI_RANGE, symbolic or can
2634 if (vr0
.type
== VR_RANGE
2635 && (vr1
.type
!= VR_RANGE
2636 || symbolic_range_p (&vr1
)
2637 || range_includes_zero_p (&vr1
)))
2639 tree zero
= build_int_cst (TREE_TYPE (vr0
.min
), 0);
2644 if (TYPE_UNSIGNED (expr_type
)
2645 || value_range_nonnegative_p (&vr1
))
2647 /* For unsigned division or when divisor is known
2648 to be non-negative, the range has to cover
2649 all numbers from 0 to max for positive max
2650 and all numbers from min to 0 for negative min. */
2651 cmp
= compare_values (vr0
.max
, zero
);
2654 else if (cmp
== 0 || cmp
== 1)
2658 cmp
= compare_values (vr0
.min
, zero
);
2661 else if (cmp
== 0 || cmp
== -1)
2668 /* Otherwise the range is -max .. max or min .. -min
2669 depending on which bound is bigger in absolute value,
2670 as the division can change the sign. */
2671 abs_extent_range (vr
, vr0
.min
, vr0
.max
);
2674 if (type
== VR_VARYING
)
2676 set_value_range_to_varying (vr
);
2682 extract_range_from_multiplicative_op_1 (vr
, code
, &vr0
, &vr1
);
2686 else if (code
== TRUNC_MOD_EXPR
)
2688 if (vr1
.type
!= VR_RANGE
2689 || symbolic_range_p (&vr1
)
2690 || range_includes_zero_p (&vr1
)
2691 || vrp_val_is_min (vr1
.min
))
2693 set_value_range_to_varying (vr
);
2697 /* Compute MAX <|vr1.min|, |vr1.max|> - 1. */
2698 max
= fold_unary_to_constant (ABS_EXPR
, expr_type
, vr1
.min
);
2699 if (tree_int_cst_lt (max
, vr1
.max
))
2701 max
= int_const_binop (MINUS_EXPR
, max
, integer_one_node
);
2702 /* If the dividend is non-negative the modulus will be
2703 non-negative as well. */
2704 if (TYPE_UNSIGNED (expr_type
)
2705 || value_range_nonnegative_p (&vr0
))
2706 min
= build_int_cst (TREE_TYPE (max
), 0);
2708 min
= fold_unary_to_constant (NEGATE_EXPR
, expr_type
, max
);
2710 else if (code
== MINUS_EXPR
)
2712 /* If we have a MINUS_EXPR with two VR_ANTI_RANGEs, drop to
2713 VR_VARYING. It would take more effort to compute a precise
2714 range for such a case. For example, if we have op0 == 1 and
2715 op1 == 1 with their ranges both being ~[0,0], we would have
2716 op0 - op1 == 0, so we cannot claim that the difference is in
2717 ~[0,0]. Note that we are guaranteed to have
2718 vr0.type == vr1.type at this point. */
2719 if (vr0
.type
== VR_ANTI_RANGE
)
2721 set_value_range_to_varying (vr
);
2725 /* For MINUS_EXPR, apply the operation to the opposite ends of
2727 min
= vrp_int_const_binop (code
, vr0
.min
, vr1
.max
);
2728 max
= vrp_int_const_binop (code
, vr0
.max
, vr1
.min
);
2730 else if (code
== BIT_AND_EXPR
|| code
== BIT_IOR_EXPR
|| code
== BIT_XOR_EXPR
)
2732 bool int_cst_range0
, int_cst_range1
;
2733 double_int may_be_nonzero0
, may_be_nonzero1
;
2734 double_int must_be_nonzero0
, must_be_nonzero1
;
2736 int_cst_range0
= zero_nonzero_bits_from_vr (&vr0
, &may_be_nonzero0
,
2738 int_cst_range1
= zero_nonzero_bits_from_vr (&vr1
, &may_be_nonzero1
,
2742 if (code
== BIT_AND_EXPR
)
2745 min
= double_int_to_tree (expr_type
,
2746 double_int_and (must_be_nonzero0
,
2748 dmax
= double_int_and (may_be_nonzero0
, may_be_nonzero1
);
2749 /* If both input ranges contain only negative values we can
2750 truncate the result range maximum to the minimum of the
2751 input range maxima. */
2752 if (int_cst_range0
&& int_cst_range1
2753 && tree_int_cst_sgn (vr0
.max
) < 0
2754 && tree_int_cst_sgn (vr1
.max
) < 0)
2756 dmax
= double_int_min (dmax
, tree_to_double_int (vr0
.max
),
2757 TYPE_UNSIGNED (expr_type
));
2758 dmax
= double_int_min (dmax
, tree_to_double_int (vr1
.max
),
2759 TYPE_UNSIGNED (expr_type
));
2761 /* If either input range contains only non-negative values
2762 we can truncate the result range maximum to the respective
2763 maximum of the input range. */
2764 if (int_cst_range0
&& tree_int_cst_sgn (vr0
.min
) >= 0)
2765 dmax
= double_int_min (dmax
, tree_to_double_int (vr0
.max
),
2766 TYPE_UNSIGNED (expr_type
));
2767 if (int_cst_range1
&& tree_int_cst_sgn (vr1
.min
) >= 0)
2768 dmax
= double_int_min (dmax
, tree_to_double_int (vr1
.max
),
2769 TYPE_UNSIGNED (expr_type
));
2770 max
= double_int_to_tree (expr_type
, dmax
);
2772 else if (code
== BIT_IOR_EXPR
)
2775 max
= double_int_to_tree (expr_type
,
2776 double_int_ior (may_be_nonzero0
,
2778 dmin
= double_int_ior (must_be_nonzero0
, must_be_nonzero1
);
2779 /* If the input ranges contain only positive values we can
2780 truncate the minimum of the result range to the maximum
2781 of the input range minima. */
2782 if (int_cst_range0
&& int_cst_range1
2783 && tree_int_cst_sgn (vr0
.min
) >= 0
2784 && tree_int_cst_sgn (vr1
.min
) >= 0)
2786 dmin
= double_int_max (dmin
, tree_to_double_int (vr0
.min
),
2787 TYPE_UNSIGNED (expr_type
));
2788 dmin
= double_int_max (dmin
, tree_to_double_int (vr1
.min
),
2789 TYPE_UNSIGNED (expr_type
));
2791 /* If either input range contains only negative values
2792 we can truncate the minimum of the result range to the
2793 respective minimum range. */
2794 if (int_cst_range0
&& tree_int_cst_sgn (vr0
.max
) < 0)
2795 dmin
= double_int_max (dmin
, tree_to_double_int (vr0
.min
),
2796 TYPE_UNSIGNED (expr_type
));
2797 if (int_cst_range1
&& tree_int_cst_sgn (vr1
.max
) < 0)
2798 dmin
= double_int_max (dmin
, tree_to_double_int (vr1
.min
),
2799 TYPE_UNSIGNED (expr_type
));
2800 min
= double_int_to_tree (expr_type
, dmin
);
2802 else if (code
== BIT_XOR_EXPR
)
2804 double_int result_zero_bits
, result_one_bits
;
2806 = double_int_ior (double_int_and (must_be_nonzero0
,
2809 (double_int_ior (may_be_nonzero0
,
2812 = double_int_ior (double_int_and
2814 double_int_not (may_be_nonzero1
)),
2817 double_int_not (may_be_nonzero0
)));
2818 max
= double_int_to_tree (expr_type
,
2819 double_int_not (result_zero_bits
));
2820 min
= double_int_to_tree (expr_type
, result_one_bits
);
2821 /* If the range has all positive or all negative values the
2822 result is better than VARYING. */
2823 if (tree_int_cst_sgn (min
) < 0
2824 || tree_int_cst_sgn (max
) >= 0)
2827 max
= min
= NULL_TREE
;
2833 /* If either MIN or MAX overflowed, then set the resulting range to
2834 VARYING. But we do accept an overflow infinity
2836 if (min
== NULL_TREE
2837 || !is_gimple_min_invariant (min
)
2838 || (TREE_OVERFLOW (min
) && !is_overflow_infinity (min
))
2840 || !is_gimple_min_invariant (max
)
2841 || (TREE_OVERFLOW (max
) && !is_overflow_infinity (max
)))
2843 set_value_range_to_varying (vr
);
2849 2) [-INF, +-INF(OVF)]
2850 3) [+-INF(OVF), +INF]
2851 4) [+-INF(OVF), +-INF(OVF)]
2852 We learn nothing when we have INF and INF(OVF) on both sides.
2853 Note that we do accept [-INF, -INF] and [+INF, +INF] without
2855 if ((vrp_val_is_min (min
) || is_overflow_infinity (min
))
2856 && (vrp_val_is_max (max
) || is_overflow_infinity (max
)))
2858 set_value_range_to_varying (vr
);
2862 cmp
= compare_values (min
, max
);
2863 if (cmp
== -2 || cmp
== 1)
2865 /* If the new range has its limits swapped around (MIN > MAX),
2866 then the operation caused one of them to wrap around, mark
2867 the new range VARYING. */
2868 set_value_range_to_varying (vr
);
2871 set_value_range (vr
, type
, min
, max
, NULL
);
2874 /* Extract range information from a binary expression OP0 CODE OP1 based on
2875 the ranges of each of its operands with resulting type EXPR_TYPE.
2876 The resulting range is stored in *VR. */
2879 extract_range_from_binary_expr (value_range_t
*vr
,
2880 enum tree_code code
,
2881 tree expr_type
, tree op0
, tree op1
)
2883 value_range_t vr0
= { VR_UNDEFINED
, NULL_TREE
, NULL_TREE
, NULL
};
2884 value_range_t vr1
= { VR_UNDEFINED
, NULL_TREE
, NULL_TREE
, NULL
};
2886 /* Get value ranges for each operand. For constant operands, create
2887 a new value range with the operand to simplify processing. */
2888 if (TREE_CODE (op0
) == SSA_NAME
)
2889 vr0
= *(get_value_range (op0
));
2890 else if (is_gimple_min_invariant (op0
))
2891 set_value_range_to_value (&vr0
, op0
, NULL
);
2893 set_value_range_to_varying (&vr0
);
2895 if (TREE_CODE (op1
) == SSA_NAME
)
2896 vr1
= *(get_value_range (op1
));
2897 else if (is_gimple_min_invariant (op1
))
2898 set_value_range_to_value (&vr1
, op1
, NULL
);
2900 set_value_range_to_varying (&vr1
);
2902 extract_range_from_binary_expr_1 (vr
, code
, expr_type
, &vr0
, &vr1
);
2905 /* Extract range information from a unary operation CODE based on
2906 the range of its operand *VR0 with type OP0_TYPE with resulting type TYPE.
2907 The The resulting range is stored in *VR. */
2910 extract_range_from_unary_expr_1 (value_range_t
*vr
,
2911 enum tree_code code
, tree type
,
2912 value_range_t
*vr0_
, tree op0_type
)
2914 value_range_t vr0
= *vr0_
;
2916 /* VRP only operates on integral and pointer types. */
2917 if (!(INTEGRAL_TYPE_P (op0_type
)
2918 || POINTER_TYPE_P (op0_type
))
2919 || !(INTEGRAL_TYPE_P (type
)
2920 || POINTER_TYPE_P (type
)))
2922 set_value_range_to_varying (vr
);
2926 /* If VR0 is UNDEFINED, so is the result. */
2927 if (vr0
.type
== VR_UNDEFINED
)
2929 set_value_range_to_undefined (vr
);
2933 if (CONVERT_EXPR_CODE_P (code
))
2935 tree inner_type
= op0_type
;
2936 tree outer_type
= type
;
2938 /* If the expression evaluates to a pointer, we are only interested in
2939 determining if it evaluates to NULL [0, 0] or non-NULL (~[0, 0]). */
2940 if (POINTER_TYPE_P (type
))
2942 if (range_is_nonnull (&vr0
))
2943 set_value_range_to_nonnull (vr
, type
);
2944 else if (range_is_null (&vr0
))
2945 set_value_range_to_null (vr
, type
);
2947 set_value_range_to_varying (vr
);
2951 /* If VR0 is varying and we increase the type precision, assume
2952 a full range for the following transformation. */
2953 if (vr0
.type
== VR_VARYING
2954 && INTEGRAL_TYPE_P (inner_type
)
2955 && TYPE_PRECISION (inner_type
) < TYPE_PRECISION (outer_type
))
2957 vr0
.type
= VR_RANGE
;
2958 vr0
.min
= TYPE_MIN_VALUE (inner_type
);
2959 vr0
.max
= TYPE_MAX_VALUE (inner_type
);
2962 /* If VR0 is a constant range or anti-range and the conversion is
2963 not truncating we can convert the min and max values and
2964 canonicalize the resulting range. Otherwise we can do the
2965 conversion if the size of the range is less than what the
2966 precision of the target type can represent and the range is
2967 not an anti-range. */
2968 if ((vr0
.type
== VR_RANGE
2969 || vr0
.type
== VR_ANTI_RANGE
)
2970 && TREE_CODE (vr0
.min
) == INTEGER_CST
2971 && TREE_CODE (vr0
.max
) == INTEGER_CST
2972 && (!is_overflow_infinity (vr0
.min
)
2973 || (vr0
.type
== VR_RANGE
2974 && TYPE_PRECISION (outer_type
) > TYPE_PRECISION (inner_type
)
2975 && needs_overflow_infinity (outer_type
)
2976 && supports_overflow_infinity (outer_type
)))
2977 && (!is_overflow_infinity (vr0
.max
)
2978 || (vr0
.type
== VR_RANGE
2979 && TYPE_PRECISION (outer_type
) > TYPE_PRECISION (inner_type
)
2980 && needs_overflow_infinity (outer_type
)
2981 && supports_overflow_infinity (outer_type
)))
2982 && (TYPE_PRECISION (outer_type
) >= TYPE_PRECISION (inner_type
)
2983 || (vr0
.type
== VR_RANGE
2984 && integer_zerop (int_const_binop (RSHIFT_EXPR
,
2985 int_const_binop (MINUS_EXPR
, vr0
.max
, vr0
.min
),
2986 size_int (TYPE_PRECISION (outer_type
)))))))
2988 tree new_min
, new_max
;
2989 if (is_overflow_infinity (vr0
.min
))
2990 new_min
= negative_overflow_infinity (outer_type
);
2992 new_min
= force_fit_type_double (outer_type
,
2993 tree_to_double_int (vr0
.min
),
2995 if (is_overflow_infinity (vr0
.max
))
2996 new_max
= positive_overflow_infinity (outer_type
);
2998 new_max
= force_fit_type_double (outer_type
,
2999 tree_to_double_int (vr0
.max
),
3001 set_and_canonicalize_value_range (vr
, vr0
.type
,
3002 new_min
, new_max
, NULL
);
3006 set_value_range_to_varying (vr
);
3009 else if (code
== NEGATE_EXPR
)
3011 /* -X is simply 0 - X, so re-use existing code that also handles
3012 anti-ranges fine. */
3013 value_range_t zero
= { VR_UNDEFINED
, NULL_TREE
, NULL_TREE
, NULL
};
3014 set_value_range_to_value (&zero
, build_int_cst (type
, 0), NULL
);
3015 extract_range_from_binary_expr_1 (vr
, MINUS_EXPR
, type
, &zero
, &vr0
);
3018 else if (code
== ABS_EXPR
)
3023 /* Pass through vr0 in the easy cases. */
3024 if (TYPE_UNSIGNED (type
)
3025 || value_range_nonnegative_p (&vr0
))
3027 copy_value_range (vr
, &vr0
);
3031 /* For the remaining varying or symbolic ranges we can't do anything
3033 if (vr0
.type
== VR_VARYING
3034 || symbolic_range_p (&vr0
))
3036 set_value_range_to_varying (vr
);
3040 /* -TYPE_MIN_VALUE = TYPE_MIN_VALUE with flag_wrapv so we can't get a
3042 if (!TYPE_OVERFLOW_UNDEFINED (type
)
3043 && ((vr0
.type
== VR_RANGE
3044 && vrp_val_is_min (vr0
.min
))
3045 || (vr0
.type
== VR_ANTI_RANGE
3046 && !vrp_val_is_min (vr0
.min
))))
3048 set_value_range_to_varying (vr
);
3052 /* ABS_EXPR may flip the range around, if the original range
3053 included negative values. */
3054 if (is_overflow_infinity (vr0
.min
))
3055 min
= positive_overflow_infinity (type
);
3056 else if (!vrp_val_is_min (vr0
.min
))
3057 min
= fold_unary_to_constant (code
, type
, vr0
.min
);
3058 else if (!needs_overflow_infinity (type
))
3059 min
= TYPE_MAX_VALUE (type
);
3060 else if (supports_overflow_infinity (type
))
3061 min
= positive_overflow_infinity (type
);
3064 set_value_range_to_varying (vr
);
3068 if (is_overflow_infinity (vr0
.max
))
3069 max
= positive_overflow_infinity (type
);
3070 else if (!vrp_val_is_min (vr0
.max
))
3071 max
= fold_unary_to_constant (code
, type
, vr0
.max
);
3072 else if (!needs_overflow_infinity (type
))
3073 max
= TYPE_MAX_VALUE (type
);
3074 else if (supports_overflow_infinity (type
)
3075 /* We shouldn't generate [+INF, +INF] as set_value_range
3076 doesn't like this and ICEs. */
3077 && !is_positive_overflow_infinity (min
))
3078 max
= positive_overflow_infinity (type
);
3081 set_value_range_to_varying (vr
);
3085 cmp
= compare_values (min
, max
);
3087 /* If a VR_ANTI_RANGEs contains zero, then we have
3088 ~[-INF, min(MIN, MAX)]. */
3089 if (vr0
.type
== VR_ANTI_RANGE
)
3091 if (range_includes_zero_p (&vr0
))
3093 /* Take the lower of the two values. */
3097 /* Create ~[-INF, min (abs(MIN), abs(MAX))]
3098 or ~[-INF + 1, min (abs(MIN), abs(MAX))] when
3099 flag_wrapv is set and the original anti-range doesn't include
3100 TYPE_MIN_VALUE, remember -TYPE_MIN_VALUE = TYPE_MIN_VALUE. */
3101 if (TYPE_OVERFLOW_WRAPS (type
))
3103 tree type_min_value
= TYPE_MIN_VALUE (type
);
3105 min
= (vr0
.min
!= type_min_value
3106 ? int_const_binop (PLUS_EXPR
, type_min_value
,
3112 if (overflow_infinity_range_p (&vr0
))
3113 min
= negative_overflow_infinity (type
);
3115 min
= TYPE_MIN_VALUE (type
);
3120 /* All else has failed, so create the range [0, INF], even for
3121 flag_wrapv since TYPE_MIN_VALUE is in the original
3123 vr0
.type
= VR_RANGE
;
3124 min
= build_int_cst (type
, 0);
3125 if (needs_overflow_infinity (type
))
3127 if (supports_overflow_infinity (type
))
3128 max
= positive_overflow_infinity (type
);
3131 set_value_range_to_varying (vr
);
3136 max
= TYPE_MAX_VALUE (type
);
3140 /* If the range contains zero then we know that the minimum value in the
3141 range will be zero. */
3142 else if (range_includes_zero_p (&vr0
))
3146 min
= build_int_cst (type
, 0);
3150 /* If the range was reversed, swap MIN and MAX. */
3159 cmp
= compare_values (min
, max
);
3160 if (cmp
== -2 || cmp
== 1)
3162 /* If the new range has its limits swapped around (MIN > MAX),
3163 then the operation caused one of them to wrap around, mark
3164 the new range VARYING. */
3165 set_value_range_to_varying (vr
);
3168 set_value_range (vr
, vr0
.type
, min
, max
, NULL
);
3171 else if (code
== BIT_NOT_EXPR
)
3173 /* ~X is simply -1 - X, so re-use existing code that also handles
3174 anti-ranges fine. */
3175 value_range_t minusone
= { VR_UNDEFINED
, NULL_TREE
, NULL_TREE
, NULL
};
3176 set_value_range_to_value (&minusone
, build_int_cst (type
, -1), NULL
);
3177 extract_range_from_binary_expr_1 (vr
, MINUS_EXPR
,
3178 type
, &minusone
, &vr0
);
3181 else if (code
== PAREN_EXPR
)
3183 copy_value_range (vr
, &vr0
);
3187 /* For unhandled operations fall back to varying. */
3188 set_value_range_to_varying (vr
);
3193 /* Extract range information from a unary expression CODE OP0 based on
3194 the range of its operand with resulting type TYPE.
3195 The resulting range is stored in *VR. */
3198 extract_range_from_unary_expr (value_range_t
*vr
, enum tree_code code
,
3199 tree type
, tree op0
)
3201 value_range_t vr0
= { VR_UNDEFINED
, NULL_TREE
, NULL_TREE
, NULL
};
3203 /* Get value ranges for the operand. For constant operands, create
3204 a new value range with the operand to simplify processing. */
3205 if (TREE_CODE (op0
) == SSA_NAME
)
3206 vr0
= *(get_value_range (op0
));
3207 else if (is_gimple_min_invariant (op0
))
3208 set_value_range_to_value (&vr0
, op0
, NULL
);
3210 set_value_range_to_varying (&vr0
);
3212 extract_range_from_unary_expr_1 (vr
, code
, type
, &vr0
, TREE_TYPE (op0
));
3216 /* Extract range information from a conditional expression STMT based on
3217 the ranges of each of its operands and the expression code. */
3220 extract_range_from_cond_expr (value_range_t
*vr
, gimple stmt
)
3223 value_range_t vr0
= { VR_UNDEFINED
, NULL_TREE
, NULL_TREE
, NULL
};
3224 value_range_t vr1
= { VR_UNDEFINED
, NULL_TREE
, NULL_TREE
, NULL
};
3226 /* Get value ranges for each operand. For constant operands, create
3227 a new value range with the operand to simplify processing. */
3228 op0
= gimple_assign_rhs2 (stmt
);
3229 if (TREE_CODE (op0
) == SSA_NAME
)
3230 vr0
= *(get_value_range (op0
));
3231 else if (is_gimple_min_invariant (op0
))
3232 set_value_range_to_value (&vr0
, op0
, NULL
);
3234 set_value_range_to_varying (&vr0
);
3236 op1
= gimple_assign_rhs3 (stmt
);
3237 if (TREE_CODE (op1
) == SSA_NAME
)
3238 vr1
= *(get_value_range (op1
));
3239 else if (is_gimple_min_invariant (op1
))
3240 set_value_range_to_value (&vr1
, op1
, NULL
);
3242 set_value_range_to_varying (&vr1
);
3244 /* The resulting value range is the union of the operand ranges */
3245 vrp_meet (&vr0
, &vr1
);
3246 copy_value_range (vr
, &vr0
);
3250 /* Extract range information from a comparison expression EXPR based
3251 on the range of its operand and the expression code. */
3254 extract_range_from_comparison (value_range_t
*vr
, enum tree_code code
,
3255 tree type
, tree op0
, tree op1
)
3260 val
= vrp_evaluate_conditional_warnv_with_ops (code
, op0
, op1
, false, &sop
,
3263 /* A disadvantage of using a special infinity as an overflow
3264 representation is that we lose the ability to record overflow
3265 when we don't have an infinity. So we have to ignore a result
3266 which relies on overflow. */
3268 if (val
&& !is_overflow_infinity (val
) && !sop
)
3270 /* Since this expression was found on the RHS of an assignment,
3271 its type may be different from _Bool. Convert VAL to EXPR's
3273 val
= fold_convert (type
, val
);
3274 if (is_gimple_min_invariant (val
))
3275 set_value_range_to_value (vr
, val
, vr
->equiv
);
3277 set_value_range (vr
, VR_RANGE
, val
, val
, vr
->equiv
);
3280 /* The result of a comparison is always true or false. */
3281 set_value_range_to_truthvalue (vr
, type
);
3284 /* Try to derive a nonnegative or nonzero range out of STMT relying
3285 primarily on generic routines in fold in conjunction with range data.
3286 Store the result in *VR */
3289 extract_range_basic (value_range_t
*vr
, gimple stmt
)
3292 tree type
= gimple_expr_type (stmt
);
3294 if (INTEGRAL_TYPE_P (type
)
3295 && gimple_stmt_nonnegative_warnv_p (stmt
, &sop
))
3296 set_value_range_to_nonnegative (vr
, type
,
3297 sop
|| stmt_overflow_infinity (stmt
));
3298 else if (vrp_stmt_computes_nonzero (stmt
, &sop
)
3300 set_value_range_to_nonnull (vr
, type
);
3302 set_value_range_to_varying (vr
);
3306 /* Try to compute a useful range out of assignment STMT and store it
3310 extract_range_from_assignment (value_range_t
*vr
, gimple stmt
)
3312 enum tree_code code
= gimple_assign_rhs_code (stmt
);
3314 if (code
== ASSERT_EXPR
)
3315 extract_range_from_assert (vr
, gimple_assign_rhs1 (stmt
));
3316 else if (code
== SSA_NAME
)
3317 extract_range_from_ssa_name (vr
, gimple_assign_rhs1 (stmt
));
3318 else if (TREE_CODE_CLASS (code
) == tcc_binary
)
3319 extract_range_from_binary_expr (vr
, gimple_assign_rhs_code (stmt
),
3320 gimple_expr_type (stmt
),
3321 gimple_assign_rhs1 (stmt
),
3322 gimple_assign_rhs2 (stmt
));
3323 else if (TREE_CODE_CLASS (code
) == tcc_unary
)
3324 extract_range_from_unary_expr (vr
, gimple_assign_rhs_code (stmt
),
3325 gimple_expr_type (stmt
),
3326 gimple_assign_rhs1 (stmt
));
3327 else if (code
== COND_EXPR
)
3328 extract_range_from_cond_expr (vr
, stmt
);
3329 else if (TREE_CODE_CLASS (code
) == tcc_comparison
)
3330 extract_range_from_comparison (vr
, gimple_assign_rhs_code (stmt
),
3331 gimple_expr_type (stmt
),
3332 gimple_assign_rhs1 (stmt
),
3333 gimple_assign_rhs2 (stmt
));
3334 else if (get_gimple_rhs_class (code
) == GIMPLE_SINGLE_RHS
3335 && is_gimple_min_invariant (gimple_assign_rhs1 (stmt
)))
3336 set_value_range_to_value (vr
, gimple_assign_rhs1 (stmt
), NULL
);
3338 set_value_range_to_varying (vr
);
3340 if (vr
->type
== VR_VARYING
)
3341 extract_range_basic (vr
, stmt
);
3344 /* Given a range VR, a LOOP and a variable VAR, determine whether it
3345 would be profitable to adjust VR using scalar evolution information
3346 for VAR. If so, update VR with the new limits. */
3349 adjust_range_with_scev (value_range_t
*vr
, struct loop
*loop
,
3350 gimple stmt
, tree var
)
3352 tree init
, step
, chrec
, tmin
, tmax
, min
, max
, type
, tem
;
3353 enum ev_direction dir
;
3355 /* TODO. Don't adjust anti-ranges. An anti-range may provide
3356 better opportunities than a regular range, but I'm not sure. */
3357 if (vr
->type
== VR_ANTI_RANGE
)
3360 chrec
= instantiate_parameters (loop
, analyze_scalar_evolution (loop
, var
));
3362 /* Like in PR19590, scev can return a constant function. */
3363 if (is_gimple_min_invariant (chrec
))
3365 set_value_range_to_value (vr
, chrec
, vr
->equiv
);
3369 if (TREE_CODE (chrec
) != POLYNOMIAL_CHREC
)
3372 init
= initial_condition_in_loop_num (chrec
, loop
->num
);
3373 tem
= op_with_constant_singleton_value_range (init
);
3376 step
= evolution_part_in_loop_num (chrec
, loop
->num
);
3377 tem
= op_with_constant_singleton_value_range (step
);
3381 /* If STEP is symbolic, we can't know whether INIT will be the
3382 minimum or maximum value in the range. Also, unless INIT is
3383 a simple expression, compare_values and possibly other functions
3384 in tree-vrp won't be able to handle it. */
3385 if (step
== NULL_TREE
3386 || !is_gimple_min_invariant (step
)
3387 || !valid_value_p (init
))
3390 dir
= scev_direction (chrec
);
3391 if (/* Do not adjust ranges if we do not know whether the iv increases
3392 or decreases, ... */
3393 dir
== EV_DIR_UNKNOWN
3394 /* ... or if it may wrap. */
3395 || scev_probably_wraps_p (init
, step
, stmt
, get_chrec_loop (chrec
),
3399 /* We use TYPE_MIN_VALUE and TYPE_MAX_VALUE here instead of
3400 negative_overflow_infinity and positive_overflow_infinity,
3401 because we have concluded that the loop probably does not
3404 type
= TREE_TYPE (var
);
3405 if (POINTER_TYPE_P (type
) || !TYPE_MIN_VALUE (type
))
3406 tmin
= lower_bound_in_type (type
, type
);
3408 tmin
= TYPE_MIN_VALUE (type
);
3409 if (POINTER_TYPE_P (type
) || !TYPE_MAX_VALUE (type
))
3410 tmax
= upper_bound_in_type (type
, type
);
3412 tmax
= TYPE_MAX_VALUE (type
);
3414 /* Try to use estimated number of iterations for the loop to constrain the
3415 final value in the evolution. */
3416 if (TREE_CODE (step
) == INTEGER_CST
3417 && is_gimple_val (init
)
3418 && (TREE_CODE (init
) != SSA_NAME
3419 || get_value_range (init
)->type
== VR_RANGE
))
3423 if (estimated_loop_iterations (loop
, true, &nit
))
3425 value_range_t maxvr
= { VR_UNDEFINED
, NULL_TREE
, NULL_TREE
, NULL
};
3427 bool unsigned_p
= TYPE_UNSIGNED (TREE_TYPE (step
));
3430 dtmp
= double_int_mul_with_sign (tree_to_double_int (step
), nit
,
3431 unsigned_p
, &overflow
);
3432 /* If the multiplication overflowed we can't do a meaningful
3433 adjustment. Likewise if the result doesn't fit in the type
3434 of the induction variable. For a signed type we have to
3435 check whether the result has the expected signedness which
3436 is that of the step as number of iterations is unsigned. */
3438 && double_int_fits_to_tree_p (TREE_TYPE (init
), dtmp
)
3440 || ((dtmp
.high
^ TREE_INT_CST_HIGH (step
)) >= 0)))
3442 tem
= double_int_to_tree (TREE_TYPE (init
), dtmp
);
3443 extract_range_from_binary_expr (&maxvr
, PLUS_EXPR
,
3444 TREE_TYPE (init
), init
, tem
);
3445 /* Likewise if the addition did. */
3446 if (maxvr
.type
== VR_RANGE
)
3455 if (vr
->type
== VR_VARYING
|| vr
->type
== VR_UNDEFINED
)
3460 /* For VARYING or UNDEFINED ranges, just about anything we get
3461 from scalar evolutions should be better. */
3463 if (dir
== EV_DIR_DECREASES
)
3468 /* If we would create an invalid range, then just assume we
3469 know absolutely nothing. This may be over-conservative,
3470 but it's clearly safe, and should happen only in unreachable
3471 parts of code, or for invalid programs. */
3472 if (compare_values (min
, max
) == 1)
3475 set_value_range (vr
, VR_RANGE
, min
, max
, vr
->equiv
);
3477 else if (vr
->type
== VR_RANGE
)
3482 if (dir
== EV_DIR_DECREASES
)
3484 /* INIT is the maximum value. If INIT is lower than VR->MAX
3485 but no smaller than VR->MIN, set VR->MAX to INIT. */
3486 if (compare_values (init
, max
) == -1)
3489 /* According to the loop information, the variable does not
3490 overflow. If we think it does, probably because of an
3491 overflow due to arithmetic on a different INF value,
3493 if (is_negative_overflow_infinity (min
)
3494 || compare_values (min
, tmin
) == -1)
3500 /* If INIT is bigger than VR->MIN, set VR->MIN to INIT. */
3501 if (compare_values (init
, min
) == 1)
3504 if (is_positive_overflow_infinity (max
)
3505 || compare_values (tmax
, max
) == -1)
3509 /* If we just created an invalid range with the minimum
3510 greater than the maximum, we fail conservatively.
3511 This should happen only in unreachable
3512 parts of code, or for invalid programs. */
3513 if (compare_values (min
, max
) == 1)
3516 set_value_range (vr
, VR_RANGE
, min
, max
, vr
->equiv
);
3520 /* Return true if VAR may overflow at STMT. This checks any available
3521 loop information to see if we can determine that VAR does not
3525 vrp_var_may_overflow (tree var
, gimple stmt
)
3528 tree chrec
, init
, step
;
3530 if (current_loops
== NULL
)
3533 l
= loop_containing_stmt (stmt
);
3538 chrec
= instantiate_parameters (l
, analyze_scalar_evolution (l
, var
));
3539 if (TREE_CODE (chrec
) != POLYNOMIAL_CHREC
)
3542 init
= initial_condition_in_loop_num (chrec
, l
->num
);
3543 step
= evolution_part_in_loop_num (chrec
, l
->num
);
3545 if (step
== NULL_TREE
3546 || !is_gimple_min_invariant (step
)
3547 || !valid_value_p (init
))
3550 /* If we get here, we know something useful about VAR based on the
3551 loop information. If it wraps, it may overflow. */
3553 if (scev_probably_wraps_p (init
, step
, stmt
, get_chrec_loop (chrec
),
3557 if (dump_file
&& (dump_flags
& TDF_DETAILS
) != 0)
3559 print_generic_expr (dump_file
, var
, 0);
3560 fprintf (dump_file
, ": loop information indicates does not overflow\n");
3567 /* Given two numeric value ranges VR0, VR1 and a comparison code COMP:
3569 - Return BOOLEAN_TRUE_NODE if VR0 COMP VR1 always returns true for
3570 all the values in the ranges.
3572 - Return BOOLEAN_FALSE_NODE if the comparison always returns false.
3574 - Return NULL_TREE if it is not always possible to determine the
3575 value of the comparison.
3577 Also set *STRICT_OVERFLOW_P to indicate whether a range with an
3578 overflow infinity was used in the test. */
3582 compare_ranges (enum tree_code comp
, value_range_t
*vr0
, value_range_t
*vr1
,
3583 bool *strict_overflow_p
)
3585 /* VARYING or UNDEFINED ranges cannot be compared. */
3586 if (vr0
->type
== VR_VARYING
3587 || vr0
->type
== VR_UNDEFINED
3588 || vr1
->type
== VR_VARYING
3589 || vr1
->type
== VR_UNDEFINED
)
3592 /* Anti-ranges need to be handled separately. */
3593 if (vr0
->type
== VR_ANTI_RANGE
|| vr1
->type
== VR_ANTI_RANGE
)
3595 /* If both are anti-ranges, then we cannot compute any
3597 if (vr0
->type
== VR_ANTI_RANGE
&& vr1
->type
== VR_ANTI_RANGE
)
3600 /* These comparisons are never statically computable. */
3607 /* Equality can be computed only between a range and an
3608 anti-range. ~[VAL1, VAL2] == [VAL1, VAL2] is always false. */
3609 if (vr0
->type
== VR_RANGE
)
3611 /* To simplify processing, make VR0 the anti-range. */
3612 value_range_t
*tmp
= vr0
;
3617 gcc_assert (comp
== NE_EXPR
|| comp
== EQ_EXPR
);
3619 if (compare_values_warnv (vr0
->min
, vr1
->min
, strict_overflow_p
) == 0
3620 && compare_values_warnv (vr0
->max
, vr1
->max
, strict_overflow_p
) == 0)
3621 return (comp
== NE_EXPR
) ? boolean_true_node
: boolean_false_node
;
3626 if (!usable_range_p (vr0
, strict_overflow_p
)
3627 || !usable_range_p (vr1
, strict_overflow_p
))
3630 /* Simplify processing. If COMP is GT_EXPR or GE_EXPR, switch the
3631 operands around and change the comparison code. */
3632 if (comp
== GT_EXPR
|| comp
== GE_EXPR
)
3635 comp
= (comp
== GT_EXPR
) ? LT_EXPR
: LE_EXPR
;
3641 if (comp
== EQ_EXPR
)
3643 /* Equality may only be computed if both ranges represent
3644 exactly one value. */
3645 if (compare_values_warnv (vr0
->min
, vr0
->max
, strict_overflow_p
) == 0
3646 && compare_values_warnv (vr1
->min
, vr1
->max
, strict_overflow_p
) == 0)
3648 int cmp_min
= compare_values_warnv (vr0
->min
, vr1
->min
,
3650 int cmp_max
= compare_values_warnv (vr0
->max
, vr1
->max
,
3652 if (cmp_min
== 0 && cmp_max
== 0)
3653 return boolean_true_node
;
3654 else if (cmp_min
!= -2 && cmp_max
!= -2)
3655 return boolean_false_node
;
3657 /* If [V0_MIN, V1_MAX] < [V1_MIN, V1_MAX] then V0 != V1. */
3658 else if (compare_values_warnv (vr0
->min
, vr1
->max
,
3659 strict_overflow_p
) == 1
3660 || compare_values_warnv (vr1
->min
, vr0
->max
,
3661 strict_overflow_p
) == 1)
3662 return boolean_false_node
;
3666 else if (comp
== NE_EXPR
)
3670 /* If VR0 is completely to the left or completely to the right
3671 of VR1, they are always different. Notice that we need to
3672 make sure that both comparisons yield similar results to
3673 avoid comparing values that cannot be compared at
3675 cmp1
= compare_values_warnv (vr0
->max
, vr1
->min
, strict_overflow_p
);
3676 cmp2
= compare_values_warnv (vr0
->min
, vr1
->max
, strict_overflow_p
);
3677 if ((cmp1
== -1 && cmp2
== -1) || (cmp1
== 1 && cmp2
== 1))
3678 return boolean_true_node
;
3680 /* If VR0 and VR1 represent a single value and are identical,
3682 else if (compare_values_warnv (vr0
->min
, vr0
->max
,
3683 strict_overflow_p
) == 0
3684 && compare_values_warnv (vr1
->min
, vr1
->max
,
3685 strict_overflow_p
) == 0
3686 && compare_values_warnv (vr0
->min
, vr1
->min
,
3687 strict_overflow_p
) == 0
3688 && compare_values_warnv (vr0
->max
, vr1
->max
,
3689 strict_overflow_p
) == 0)
3690 return boolean_false_node
;
3692 /* Otherwise, they may or may not be different. */
3696 else if (comp
== LT_EXPR
|| comp
== LE_EXPR
)
3700 /* If VR0 is to the left of VR1, return true. */
3701 tst
= compare_values_warnv (vr0
->max
, vr1
->min
, strict_overflow_p
);
3702 if ((comp
== LT_EXPR
&& tst
== -1)
3703 || (comp
== LE_EXPR
&& (tst
== -1 || tst
== 0)))
3705 if (overflow_infinity_range_p (vr0
)
3706 || overflow_infinity_range_p (vr1
))
3707 *strict_overflow_p
= true;
3708 return boolean_true_node
;
3711 /* If VR0 is to the right of VR1, return false. */
3712 tst
= compare_values_warnv (vr0
->min
, vr1
->max
, strict_overflow_p
);
3713 if ((comp
== LT_EXPR
&& (tst
== 0 || tst
== 1))
3714 || (comp
== LE_EXPR
&& tst
== 1))
3716 if (overflow_infinity_range_p (vr0
)
3717 || overflow_infinity_range_p (vr1
))
3718 *strict_overflow_p
= true;
3719 return boolean_false_node
;
3722 /* Otherwise, we don't know. */
3730 /* Given a value range VR, a value VAL and a comparison code COMP, return
3731 BOOLEAN_TRUE_NODE if VR COMP VAL always returns true for all the
3732 values in VR. Return BOOLEAN_FALSE_NODE if the comparison
3733 always returns false. Return NULL_TREE if it is not always
3734 possible to determine the value of the comparison. Also set
3735 *STRICT_OVERFLOW_P to indicate whether a range with an overflow
3736 infinity was used in the test. */
3739 compare_range_with_value (enum tree_code comp
, value_range_t
*vr
, tree val
,
3740 bool *strict_overflow_p
)
3742 if (vr
->type
== VR_VARYING
|| vr
->type
== VR_UNDEFINED
)
3745 /* Anti-ranges need to be handled separately. */
3746 if (vr
->type
== VR_ANTI_RANGE
)
3748 /* For anti-ranges, the only predicates that we can compute at
3749 compile time are equality and inequality. */
3756 /* ~[VAL_1, VAL_2] OP VAL is known if VAL_1 <= VAL <= VAL_2. */
3757 if (value_inside_range (val
, vr
) == 1)
3758 return (comp
== NE_EXPR
) ? boolean_true_node
: boolean_false_node
;
3763 if (!usable_range_p (vr
, strict_overflow_p
))
3766 if (comp
== EQ_EXPR
)
3768 /* EQ_EXPR may only be computed if VR represents exactly
3770 if (compare_values_warnv (vr
->min
, vr
->max
, strict_overflow_p
) == 0)
3772 int cmp
= compare_values_warnv (vr
->min
, val
, strict_overflow_p
);
3774 return boolean_true_node
;
3775 else if (cmp
== -1 || cmp
== 1 || cmp
== 2)
3776 return boolean_false_node
;
3778 else if (compare_values_warnv (val
, vr
->min
, strict_overflow_p
) == -1
3779 || compare_values_warnv (vr
->max
, val
, strict_overflow_p
) == -1)
3780 return boolean_false_node
;
3784 else if (comp
== NE_EXPR
)
3786 /* If VAL is not inside VR, then they are always different. */
3787 if (compare_values_warnv (vr
->max
, val
, strict_overflow_p
) == -1
3788 || compare_values_warnv (vr
->min
, val
, strict_overflow_p
) == 1)
3789 return boolean_true_node
;
3791 /* If VR represents exactly one value equal to VAL, then return
3793 if (compare_values_warnv (vr
->min
, vr
->max
, strict_overflow_p
) == 0
3794 && compare_values_warnv (vr
->min
, val
, strict_overflow_p
) == 0)
3795 return boolean_false_node
;
3797 /* Otherwise, they may or may not be different. */
3800 else if (comp
== LT_EXPR
|| comp
== LE_EXPR
)
3804 /* If VR is to the left of VAL, return true. */
3805 tst
= compare_values_warnv (vr
->max
, val
, strict_overflow_p
);
3806 if ((comp
== LT_EXPR
&& tst
== -1)
3807 || (comp
== LE_EXPR
&& (tst
== -1 || tst
== 0)))
3809 if (overflow_infinity_range_p (vr
))
3810 *strict_overflow_p
= true;
3811 return boolean_true_node
;
3814 /* If VR is to the right of VAL, return false. */
3815 tst
= compare_values_warnv (vr
->min
, val
, strict_overflow_p
);
3816 if ((comp
== LT_EXPR
&& (tst
== 0 || tst
== 1))
3817 || (comp
== LE_EXPR
&& tst
== 1))
3819 if (overflow_infinity_range_p (vr
))
3820 *strict_overflow_p
= true;
3821 return boolean_false_node
;
3824 /* Otherwise, we don't know. */
3827 else if (comp
== GT_EXPR
|| comp
== GE_EXPR
)
3831 /* If VR is to the right of VAL, return true. */
3832 tst
= compare_values_warnv (vr
->min
, val
, strict_overflow_p
);
3833 if ((comp
== GT_EXPR
&& tst
== 1)
3834 || (comp
== GE_EXPR
&& (tst
== 0 || tst
== 1)))
3836 if (overflow_infinity_range_p (vr
))
3837 *strict_overflow_p
= true;
3838 return boolean_true_node
;
3841 /* If VR is to the left of VAL, return false. */
3842 tst
= compare_values_warnv (vr
->max
, val
, strict_overflow_p
);
3843 if ((comp
== GT_EXPR
&& (tst
== -1 || tst
== 0))
3844 || (comp
== GE_EXPR
&& tst
== -1))
3846 if (overflow_infinity_range_p (vr
))
3847 *strict_overflow_p
= true;
3848 return boolean_false_node
;
3851 /* Otherwise, we don't know. */
3859 /* Debugging dumps. */
3861 void dump_value_range (FILE *, value_range_t
*);
3862 void debug_value_range (value_range_t
*);
3863 void dump_all_value_ranges (FILE *);
3864 void debug_all_value_ranges (void);
3865 void dump_vr_equiv (FILE *, bitmap
);
3866 void debug_vr_equiv (bitmap
);
3869 /* Dump value range VR to FILE. */
3872 dump_value_range (FILE *file
, value_range_t
*vr
)
3875 fprintf (file
, "[]");
3876 else if (vr
->type
== VR_UNDEFINED
)
3877 fprintf (file
, "UNDEFINED");
3878 else if (vr
->type
== VR_RANGE
|| vr
->type
== VR_ANTI_RANGE
)
3880 tree type
= TREE_TYPE (vr
->min
);
3882 fprintf (file
, "%s[", (vr
->type
== VR_ANTI_RANGE
) ? "~" : "");
3884 if (is_negative_overflow_infinity (vr
->min
))
3885 fprintf (file
, "-INF(OVF)");
3886 else if (INTEGRAL_TYPE_P (type
)
3887 && !TYPE_UNSIGNED (type
)
3888 && vrp_val_is_min (vr
->min
))
3889 fprintf (file
, "-INF");
3891 print_generic_expr (file
, vr
->min
, 0);
3893 fprintf (file
, ", ");
3895 if (is_positive_overflow_infinity (vr
->max
))
3896 fprintf (file
, "+INF(OVF)");
3897 else if (INTEGRAL_TYPE_P (type
)
3898 && vrp_val_is_max (vr
->max
))
3899 fprintf (file
, "+INF");
3901 print_generic_expr (file
, vr
->max
, 0);
3903 fprintf (file
, "]");
3910 fprintf (file
, " EQUIVALENCES: { ");
3912 EXECUTE_IF_SET_IN_BITMAP (vr
->equiv
, 0, i
, bi
)
3914 print_generic_expr (file
, ssa_name (i
), 0);
3915 fprintf (file
, " ");
3919 fprintf (file
, "} (%u elements)", c
);
3922 else if (vr
->type
== VR_VARYING
)
3923 fprintf (file
, "VARYING");
3925 fprintf (file
, "INVALID RANGE");
3929 /* Dump value range VR to stderr. */
3932 debug_value_range (value_range_t
*vr
)
3934 dump_value_range (stderr
, vr
);
3935 fprintf (stderr
, "\n");
3939 /* Dump value ranges of all SSA_NAMEs to FILE. */
3942 dump_all_value_ranges (FILE *file
)
3946 for (i
= 0; i
< num_vr_values
; i
++)
3950 print_generic_expr (file
, ssa_name (i
), 0);
3951 fprintf (file
, ": ");
3952 dump_value_range (file
, vr_value
[i
]);
3953 fprintf (file
, "\n");
3957 fprintf (file
, "\n");
3961 /* Dump all value ranges to stderr. */
3964 debug_all_value_ranges (void)
3966 dump_all_value_ranges (stderr
);
3970 /* Given a COND_EXPR COND of the form 'V OP W', and an SSA name V,
3971 create a new SSA name N and return the assertion assignment
3972 'V = ASSERT_EXPR <V, V OP W>'. */
3975 build_assert_expr_for (tree cond
, tree v
)
3980 gcc_assert (TREE_CODE (v
) == SSA_NAME
);
3981 n
= duplicate_ssa_name (v
, NULL
);
3983 if (COMPARISON_CLASS_P (cond
))
3985 tree a
= build2 (ASSERT_EXPR
, TREE_TYPE (v
), v
, cond
);
3986 assertion
= gimple_build_assign (n
, a
);
3988 else if (TREE_CODE (cond
) == SSA_NAME
)
3990 /* Given V, build the assignment N = true. */
3991 gcc_assert (v
== cond
);
3992 assertion
= gimple_build_assign (n
, boolean_true_node
);
3997 SSA_NAME_DEF_STMT (n
) = assertion
;
3999 /* The new ASSERT_EXPR, creates a new SSA name that replaces the
4000 operand of the ASSERT_EXPR. Register the new name and the old one
4001 in the replacement table so that we can fix the SSA web after
4002 adding all the ASSERT_EXPRs. */
4003 register_new_name_mapping (n
, v
);
4009 /* Return false if EXPR is a predicate expression involving floating
4013 fp_predicate (gimple stmt
)
4015 GIMPLE_CHECK (stmt
, GIMPLE_COND
);
4017 return FLOAT_TYPE_P (TREE_TYPE (gimple_cond_lhs (stmt
)));
4021 /* If the range of values taken by OP can be inferred after STMT executes,
4022 return the comparison code (COMP_CODE_P) and value (VAL_P) that
4023 describes the inferred range. Return true if a range could be
4027 infer_value_range (gimple stmt
, tree op
, enum tree_code
*comp_code_p
, tree
*val_p
)
4030 *comp_code_p
= ERROR_MARK
;
4032 /* Do not attempt to infer anything in names that flow through
4034 if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (op
))
4037 /* Similarly, don't infer anything from statements that may throw
4039 if (stmt_could_throw_p (stmt
))
4042 /* If STMT is the last statement of a basic block with no
4043 successors, there is no point inferring anything about any of its
4044 operands. We would not be able to find a proper insertion point
4045 for the assertion, anyway. */
4046 if (stmt_ends_bb_p (stmt
) && EDGE_COUNT (gimple_bb (stmt
)->succs
) == 0)
4049 /* We can only assume that a pointer dereference will yield
4050 non-NULL if -fdelete-null-pointer-checks is enabled. */
4051 if (flag_delete_null_pointer_checks
4052 && POINTER_TYPE_P (TREE_TYPE (op
))
4053 && gimple_code (stmt
) != GIMPLE_ASM
)
4055 unsigned num_uses
, num_loads
, num_stores
;
4057 count_uses_and_derefs (op
, stmt
, &num_uses
, &num_loads
, &num_stores
);
4058 if (num_loads
+ num_stores
> 0)
4060 *val_p
= build_int_cst (TREE_TYPE (op
), 0);
4061 *comp_code_p
= NE_EXPR
;
4070 void dump_asserts_for (FILE *, tree
);
4071 void debug_asserts_for (tree
);
4072 void dump_all_asserts (FILE *);
4073 void debug_all_asserts (void);
4075 /* Dump all the registered assertions for NAME to FILE. */
4078 dump_asserts_for (FILE *file
, tree name
)
4082 fprintf (file
, "Assertions to be inserted for ");
4083 print_generic_expr (file
, name
, 0);
4084 fprintf (file
, "\n");
4086 loc
= asserts_for
[SSA_NAME_VERSION (name
)];
4089 fprintf (file
, "\t");
4090 print_gimple_stmt (file
, gsi_stmt (loc
->si
), 0, 0);
4091 fprintf (file
, "\n\tBB #%d", loc
->bb
->index
);
4094 fprintf (file
, "\n\tEDGE %d->%d", loc
->e
->src
->index
,
4095 loc
->e
->dest
->index
);
4096 dump_edge_info (file
, loc
->e
, 0);
4098 fprintf (file
, "\n\tPREDICATE: ");
4099 print_generic_expr (file
, name
, 0);
4100 fprintf (file
, " %s ", tree_code_name
[(int)loc
->comp_code
]);
4101 print_generic_expr (file
, loc
->val
, 0);
4102 fprintf (file
, "\n\n");
4106 fprintf (file
, "\n");
4110 /* Dump all the registered assertions for NAME to stderr. */
4113 debug_asserts_for (tree name
)
4115 dump_asserts_for (stderr
, name
);
4119 /* Dump all the registered assertions for all the names to FILE. */
4122 dump_all_asserts (FILE *file
)
4127 fprintf (file
, "\nASSERT_EXPRs to be inserted\n\n");
4128 EXECUTE_IF_SET_IN_BITMAP (need_assert_for
, 0, i
, bi
)
4129 dump_asserts_for (file
, ssa_name (i
));
4130 fprintf (file
, "\n");
4134 /* Dump all the registered assertions for all the names to stderr. */
4137 debug_all_asserts (void)
4139 dump_all_asserts (stderr
);
4143 /* If NAME doesn't have an ASSERT_EXPR registered for asserting
4144 'EXPR COMP_CODE VAL' at a location that dominates block BB or
4145 E->DEST, then register this location as a possible insertion point
4146 for ASSERT_EXPR <NAME, EXPR COMP_CODE VAL>.
4148 BB, E and SI provide the exact insertion point for the new
4149 ASSERT_EXPR. If BB is NULL, then the ASSERT_EXPR is to be inserted
4150 on edge E. Otherwise, if E is NULL, the ASSERT_EXPR is inserted on
4151 BB. If SI points to a COND_EXPR or a SWITCH_EXPR statement, then E
4152 must not be NULL. */
4155 register_new_assert_for (tree name
, tree expr
,
4156 enum tree_code comp_code
,
4160 gimple_stmt_iterator si
)
4162 assert_locus_t n
, loc
, last_loc
;
4163 basic_block dest_bb
;
4165 gcc_checking_assert (bb
== NULL
|| e
== NULL
);
4168 gcc_checking_assert (gimple_code (gsi_stmt (si
)) != GIMPLE_COND
4169 && gimple_code (gsi_stmt (si
)) != GIMPLE_SWITCH
);
4171 /* Never build an assert comparing against an integer constant with
4172 TREE_OVERFLOW set. This confuses our undefined overflow warning
4174 if (TREE_CODE (val
) == INTEGER_CST
4175 && TREE_OVERFLOW (val
))
4176 val
= build_int_cst_wide (TREE_TYPE (val
),
4177 TREE_INT_CST_LOW (val
), TREE_INT_CST_HIGH (val
));
4179 /* The new assertion A will be inserted at BB or E. We need to
4180 determine if the new location is dominated by a previously
4181 registered location for A. If we are doing an edge insertion,
4182 assume that A will be inserted at E->DEST. Note that this is not
4185 If E is a critical edge, it will be split. But even if E is
4186 split, the new block will dominate the same set of blocks that
4189 The reverse, however, is not true, blocks dominated by E->DEST
4190 will not be dominated by the new block created to split E. So,
4191 if the insertion location is on a critical edge, we will not use
4192 the new location to move another assertion previously registered
4193 at a block dominated by E->DEST. */
4194 dest_bb
= (bb
) ? bb
: e
->dest
;
4196 /* If NAME already has an ASSERT_EXPR registered for COMP_CODE and
4197 VAL at a block dominating DEST_BB, then we don't need to insert a new
4198 one. Similarly, if the same assertion already exists at a block
4199 dominated by DEST_BB and the new location is not on a critical
4200 edge, then update the existing location for the assertion (i.e.,
4201 move the assertion up in the dominance tree).
4203 Note, this is implemented as a simple linked list because there
4204 should not be more than a handful of assertions registered per
4205 name. If this becomes a performance problem, a table hashed by
4206 COMP_CODE and VAL could be implemented. */
4207 loc
= asserts_for
[SSA_NAME_VERSION (name
)];
4211 if (loc
->comp_code
== comp_code
4213 || operand_equal_p (loc
->val
, val
, 0))
4214 && (loc
->expr
== expr
4215 || operand_equal_p (loc
->expr
, expr
, 0)))
4217 /* If the assertion NAME COMP_CODE VAL has already been
4218 registered at a basic block that dominates DEST_BB, then
4219 we don't need to insert the same assertion again. Note
4220 that we don't check strict dominance here to avoid
4221 replicating the same assertion inside the same basic
4222 block more than once (e.g., when a pointer is
4223 dereferenced several times inside a block).
4225 An exception to this rule are edge insertions. If the
4226 new assertion is to be inserted on edge E, then it will
4227 dominate all the other insertions that we may want to
4228 insert in DEST_BB. So, if we are doing an edge
4229 insertion, don't do this dominance check. */
4231 && dominated_by_p (CDI_DOMINATORS
, dest_bb
, loc
->bb
))
4234 /* Otherwise, if E is not a critical edge and DEST_BB
4235 dominates the existing location for the assertion, move
4236 the assertion up in the dominance tree by updating its
4237 location information. */
4238 if ((e
== NULL
|| !EDGE_CRITICAL_P (e
))
4239 && dominated_by_p (CDI_DOMINATORS
, loc
->bb
, dest_bb
))
4248 /* Update the last node of the list and move to the next one. */
4253 /* If we didn't find an assertion already registered for
4254 NAME COMP_CODE VAL, add a new one at the end of the list of
4255 assertions associated with NAME. */
4256 n
= XNEW (struct assert_locus_d
);
4260 n
->comp_code
= comp_code
;
4268 asserts_for
[SSA_NAME_VERSION (name
)] = n
;
4270 bitmap_set_bit (need_assert_for
, SSA_NAME_VERSION (name
));
4273 /* (COND_OP0 COND_CODE COND_OP1) is a predicate which uses NAME.
4274 Extract a suitable test code and value and store them into *CODE_P and
4275 *VAL_P so the predicate is normalized to NAME *CODE_P *VAL_P.
4277 If no extraction was possible, return FALSE, otherwise return TRUE.
4279 If INVERT is true, then we invert the result stored into *CODE_P. */
4282 extract_code_and_val_from_cond_with_ops (tree name
, enum tree_code cond_code
,
4283 tree cond_op0
, tree cond_op1
,
4284 bool invert
, enum tree_code
*code_p
,
4287 enum tree_code comp_code
;
4290 /* Otherwise, we have a comparison of the form NAME COMP VAL
4291 or VAL COMP NAME. */
4292 if (name
== cond_op1
)
4294 /* If the predicate is of the form VAL COMP NAME, flip
4295 COMP around because we need to register NAME as the
4296 first operand in the predicate. */
4297 comp_code
= swap_tree_comparison (cond_code
);
4302 /* The comparison is of the form NAME COMP VAL, so the
4303 comparison code remains unchanged. */
4304 comp_code
= cond_code
;
4308 /* Invert the comparison code as necessary. */
4310 comp_code
= invert_tree_comparison (comp_code
, 0);
4312 /* VRP does not handle float types. */
4313 if (SCALAR_FLOAT_TYPE_P (TREE_TYPE (val
)))
4316 /* Do not register always-false predicates.
4317 FIXME: this works around a limitation in fold() when dealing with
4318 enumerations. Given 'enum { N1, N2 } x;', fold will not
4319 fold 'if (x > N2)' to 'if (0)'. */
4320 if ((comp_code
== GT_EXPR
|| comp_code
== LT_EXPR
)
4321 && INTEGRAL_TYPE_P (TREE_TYPE (val
)))
4323 tree min
= TYPE_MIN_VALUE (TREE_TYPE (val
));
4324 tree max
= TYPE_MAX_VALUE (TREE_TYPE (val
));
4326 if (comp_code
== GT_EXPR
4328 || compare_values (val
, max
) == 0))
4331 if (comp_code
== LT_EXPR
4333 || compare_values (val
, min
) == 0))
4336 *code_p
= comp_code
;
4341 /* Find out smallest RES where RES > VAL && (RES & MASK) == RES, if any
4342 (otherwise return VAL). VAL and MASK must be zero-extended for
4343 precision PREC. If SGNBIT is non-zero, first xor VAL with SGNBIT
4344 (to transform signed values into unsigned) and at the end xor
4348 masked_increment (double_int val
, double_int mask
, double_int sgnbit
,
4351 double_int bit
= double_int_one
, res
;
4354 val
= double_int_xor (val
, sgnbit
);
4355 for (i
= 0; i
< prec
; i
++, bit
= double_int_add (bit
, bit
))
4358 if (double_int_zero_p (double_int_and (res
, bit
)))
4360 res
= double_int_sub (bit
, double_int_one
);
4361 res
= double_int_and_not (double_int_add (val
, bit
), res
);
4362 res
= double_int_and (res
, mask
);
4363 if (double_int_ucmp (res
, val
) > 0)
4364 return double_int_xor (res
, sgnbit
);
4366 return double_int_xor (val
, sgnbit
);
4369 /* Try to register an edge assertion for SSA name NAME on edge E for
4370 the condition COND contributing to the conditional jump pointed to by BSI.
4371 Invert the condition COND if INVERT is true.
4372 Return true if an assertion for NAME could be registered. */
4375 register_edge_assert_for_2 (tree name
, edge e
, gimple_stmt_iterator bsi
,
4376 enum tree_code cond_code
,
4377 tree cond_op0
, tree cond_op1
, bool invert
)
4380 enum tree_code comp_code
;
4381 bool retval
= false;
4383 if (!extract_code_and_val_from_cond_with_ops (name
, cond_code
,
4386 invert
, &comp_code
, &val
))
4389 /* Only register an ASSERT_EXPR if NAME was found in the sub-graph
4390 reachable from E. */
4391 if (live_on_edge (e
, name
)
4392 && !has_single_use (name
))
4394 register_new_assert_for (name
, name
, comp_code
, val
, NULL
, e
, bsi
);
4398 /* In the case of NAME <= CST and NAME being defined as
4399 NAME = (unsigned) NAME2 + CST2 we can assert NAME2 >= -CST2
4400 and NAME2 <= CST - CST2. We can do the same for NAME > CST.
4401 This catches range and anti-range tests. */
4402 if ((comp_code
== LE_EXPR
4403 || comp_code
== GT_EXPR
)
4404 && TREE_CODE (val
) == INTEGER_CST
4405 && TYPE_UNSIGNED (TREE_TYPE (val
)))
4407 gimple def_stmt
= SSA_NAME_DEF_STMT (name
);
4408 tree cst2
= NULL_TREE
, name2
= NULL_TREE
, name3
= NULL_TREE
;
4410 /* Extract CST2 from the (optional) addition. */
4411 if (is_gimple_assign (def_stmt
)
4412 && gimple_assign_rhs_code (def_stmt
) == PLUS_EXPR
)
4414 name2
= gimple_assign_rhs1 (def_stmt
);
4415 cst2
= gimple_assign_rhs2 (def_stmt
);
4416 if (TREE_CODE (name2
) == SSA_NAME
4417 && TREE_CODE (cst2
) == INTEGER_CST
)
4418 def_stmt
= SSA_NAME_DEF_STMT (name2
);
4421 /* Extract NAME2 from the (optional) sign-changing cast. */
4422 if (gimple_assign_cast_p (def_stmt
))
4424 if (CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (def_stmt
))
4425 && ! TYPE_UNSIGNED (TREE_TYPE (gimple_assign_rhs1 (def_stmt
)))
4426 && (TYPE_PRECISION (gimple_expr_type (def_stmt
))
4427 == TYPE_PRECISION (TREE_TYPE (gimple_assign_rhs1 (def_stmt
)))))
4428 name3
= gimple_assign_rhs1 (def_stmt
);
4431 /* If name3 is used later, create an ASSERT_EXPR for it. */
4432 if (name3
!= NULL_TREE
4433 && TREE_CODE (name3
) == SSA_NAME
4434 && (cst2
== NULL_TREE
4435 || TREE_CODE (cst2
) == INTEGER_CST
)
4436 && INTEGRAL_TYPE_P (TREE_TYPE (name3
))
4437 && live_on_edge (e
, name3
)
4438 && !has_single_use (name3
))
4442 /* Build an expression for the range test. */
4443 tmp
= build1 (NOP_EXPR
, TREE_TYPE (name
), name3
);
4444 if (cst2
!= NULL_TREE
)
4445 tmp
= build2 (PLUS_EXPR
, TREE_TYPE (name
), tmp
, cst2
);
4449 fprintf (dump_file
, "Adding assert for ");
4450 print_generic_expr (dump_file
, name3
, 0);
4451 fprintf (dump_file
, " from ");
4452 print_generic_expr (dump_file
, tmp
, 0);
4453 fprintf (dump_file
, "\n");
4456 register_new_assert_for (name3
, tmp
, comp_code
, val
, NULL
, e
, bsi
);
4461 /* If name2 is used later, create an ASSERT_EXPR for it. */
4462 if (name2
!= NULL_TREE
4463 && TREE_CODE (name2
) == SSA_NAME
4464 && TREE_CODE (cst2
) == INTEGER_CST
4465 && INTEGRAL_TYPE_P (TREE_TYPE (name2
))
4466 && live_on_edge (e
, name2
)
4467 && !has_single_use (name2
))
4471 /* Build an expression for the range test. */
4473 if (TREE_TYPE (name
) != TREE_TYPE (name2
))
4474 tmp
= build1 (NOP_EXPR
, TREE_TYPE (name
), tmp
);
4475 if (cst2
!= NULL_TREE
)
4476 tmp
= build2 (PLUS_EXPR
, TREE_TYPE (name
), tmp
, cst2
);
4480 fprintf (dump_file
, "Adding assert for ");
4481 print_generic_expr (dump_file
, name2
, 0);
4482 fprintf (dump_file
, " from ");
4483 print_generic_expr (dump_file
, tmp
, 0);
4484 fprintf (dump_file
, "\n");
4487 register_new_assert_for (name2
, tmp
, comp_code
, val
, NULL
, e
, bsi
);
4493 if (TREE_CODE_CLASS (comp_code
) == tcc_comparison
4494 && TREE_CODE (val
) == INTEGER_CST
)
4496 gimple def_stmt
= SSA_NAME_DEF_STMT (name
);
4497 tree name2
= NULL_TREE
, names
[2], cst2
= NULL_TREE
;
4498 tree val2
= NULL_TREE
;
4499 double_int mask
= double_int_zero
;
4500 unsigned int prec
= TYPE_PRECISION (TREE_TYPE (val
));
4502 /* Add asserts for NAME cmp CST and NAME being defined
4503 as NAME = (int) NAME2. */
4504 if (!TYPE_UNSIGNED (TREE_TYPE (val
))
4505 && (comp_code
== LE_EXPR
|| comp_code
== LT_EXPR
4506 || comp_code
== GT_EXPR
|| comp_code
== GE_EXPR
)
4507 && gimple_assign_cast_p (def_stmt
))
4509 name2
= gimple_assign_rhs1 (def_stmt
);
4510 if (CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (def_stmt
))
4511 && INTEGRAL_TYPE_P (TREE_TYPE (name2
))
4512 && TYPE_UNSIGNED (TREE_TYPE (name2
))
4513 && prec
== TYPE_PRECISION (TREE_TYPE (name2
))
4514 && (comp_code
== LE_EXPR
|| comp_code
== GT_EXPR
4515 || !tree_int_cst_equal (val
,
4516 TYPE_MIN_VALUE (TREE_TYPE (val
))))
4517 && live_on_edge (e
, name2
)
4518 && !has_single_use (name2
))
4521 enum tree_code new_comp_code
= comp_code
;
4523 cst
= fold_convert (TREE_TYPE (name2
),
4524 TYPE_MIN_VALUE (TREE_TYPE (val
)));
4525 /* Build an expression for the range test. */
4526 tmp
= build2 (PLUS_EXPR
, TREE_TYPE (name2
), name2
, cst
);
4527 cst
= fold_build2 (PLUS_EXPR
, TREE_TYPE (name2
), cst
,
4528 fold_convert (TREE_TYPE (name2
), val
));
4529 if (comp_code
== LT_EXPR
|| comp_code
== GE_EXPR
)
4531 new_comp_code
= comp_code
== LT_EXPR
? LE_EXPR
: GT_EXPR
;
4532 cst
= fold_build2 (MINUS_EXPR
, TREE_TYPE (name2
), cst
,
4533 build_int_cst (TREE_TYPE (name2
), 1));
4538 fprintf (dump_file
, "Adding assert for ");
4539 print_generic_expr (dump_file
, name2
, 0);
4540 fprintf (dump_file
, " from ");
4541 print_generic_expr (dump_file
, tmp
, 0);
4542 fprintf (dump_file
, "\n");
4545 register_new_assert_for (name2
, tmp
, new_comp_code
, cst
, NULL
,
4552 /* Add asserts for NAME cmp CST and NAME being defined as
4553 NAME = NAME2 >> CST2.
4555 Extract CST2 from the right shift. */
4556 if (is_gimple_assign (def_stmt
)
4557 && gimple_assign_rhs_code (def_stmt
) == RSHIFT_EXPR
)
4559 name2
= gimple_assign_rhs1 (def_stmt
);
4560 cst2
= gimple_assign_rhs2 (def_stmt
);
4561 if (TREE_CODE (name2
) == SSA_NAME
4562 && host_integerp (cst2
, 1)
4563 && INTEGRAL_TYPE_P (TREE_TYPE (name2
))
4564 && IN_RANGE (tree_low_cst (cst2
, 1), 1, prec
- 1)
4565 && prec
<= 2 * HOST_BITS_PER_WIDE_INT
4566 && live_on_edge (e
, name2
)
4567 && !has_single_use (name2
))
4569 mask
= double_int_mask (tree_low_cst (cst2
, 1));
4570 val2
= fold_binary (LSHIFT_EXPR
, TREE_TYPE (val
), val
, cst2
);
4573 if (val2
!= NULL_TREE
4574 && TREE_CODE (val2
) == INTEGER_CST
4575 && simple_cst_equal (fold_build2 (RSHIFT_EXPR
,
4579 enum tree_code new_comp_code
= comp_code
;
4583 if (comp_code
== EQ_EXPR
|| comp_code
== NE_EXPR
)
4585 if (!TYPE_UNSIGNED (TREE_TYPE (val
)))
4587 tree type
= build_nonstandard_integer_type (prec
, 1);
4588 tmp
= build1 (NOP_EXPR
, type
, name2
);
4589 val2
= fold_convert (type
, val2
);
4591 tmp
= fold_build2 (MINUS_EXPR
, TREE_TYPE (tmp
), tmp
, val2
);
4592 new_val
= double_int_to_tree (TREE_TYPE (tmp
), mask
);
4593 new_comp_code
= comp_code
== EQ_EXPR
? LE_EXPR
: GT_EXPR
;
4595 else if (comp_code
== LT_EXPR
|| comp_code
== GE_EXPR
)
4599 mask
= double_int_ior (tree_to_double_int (val2
), mask
);
4600 if (double_int_minus_one_p (double_int_sext (mask
, prec
)))
4601 new_val
= NULL_TREE
;
4603 new_val
= double_int_to_tree (TREE_TYPE (val2
), mask
);
4610 fprintf (dump_file
, "Adding assert for ");
4611 print_generic_expr (dump_file
, name2
, 0);
4612 fprintf (dump_file
, " from ");
4613 print_generic_expr (dump_file
, tmp
, 0);
4614 fprintf (dump_file
, "\n");
4617 register_new_assert_for (name2
, tmp
, new_comp_code
, new_val
,
4623 /* Add asserts for NAME cmp CST and NAME being defined as
4624 NAME = NAME2 & CST2.
4626 Extract CST2 from the and. */
4627 names
[0] = NULL_TREE
;
4628 names
[1] = NULL_TREE
;
4630 if (is_gimple_assign (def_stmt
)
4631 && gimple_assign_rhs_code (def_stmt
) == BIT_AND_EXPR
)
4633 name2
= gimple_assign_rhs1 (def_stmt
);
4634 cst2
= gimple_assign_rhs2 (def_stmt
);
4635 if (TREE_CODE (name2
) == SSA_NAME
4636 && INTEGRAL_TYPE_P (TREE_TYPE (name2
))
4637 && TREE_CODE (cst2
) == INTEGER_CST
4638 && !integer_zerop (cst2
)
4639 && prec
<= 2 * HOST_BITS_PER_WIDE_INT
4641 || TYPE_UNSIGNED (TREE_TYPE (val
))))
4643 gimple def_stmt2
= SSA_NAME_DEF_STMT (name2
);
4644 if (gimple_assign_cast_p (def_stmt2
))
4646 names
[1] = gimple_assign_rhs1 (def_stmt2
);
4647 if (!CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (def_stmt2
))
4648 || !INTEGRAL_TYPE_P (TREE_TYPE (names
[1]))
4649 || (TYPE_PRECISION (TREE_TYPE (name2
))
4650 != TYPE_PRECISION (TREE_TYPE (names
[1])))
4651 || !live_on_edge (e
, names
[1])
4652 || has_single_use (names
[1]))
4653 names
[1] = NULL_TREE
;
4655 if (live_on_edge (e
, name2
)
4656 && !has_single_use (name2
))
4660 if (names
[0] || names
[1])
4662 double_int minv
, maxv
= double_int_zero
, valv
, cst2v
;
4663 double_int tem
, sgnbit
;
4664 bool valid_p
= false, valn
= false, cst2n
= false;
4665 enum tree_code ccode
= comp_code
;
4667 valv
= double_int_zext (tree_to_double_int (val
), prec
);
4668 cst2v
= double_int_zext (tree_to_double_int (cst2
), prec
);
4669 if (!TYPE_UNSIGNED (TREE_TYPE (val
)))
4671 valn
= double_int_negative_p (double_int_sext (valv
, prec
));
4672 cst2n
= double_int_negative_p (double_int_sext (cst2v
, prec
));
4674 /* If CST2 doesn't have most significant bit set,
4675 but VAL is negative, we have comparison like
4676 if ((x & 0x123) > -4) (always true). Just give up. */
4680 sgnbit
= double_int_zext (double_int_lshift (double_int_one
,
4684 sgnbit
= double_int_zero
;
4685 minv
= double_int_and (valv
, cst2v
);
4689 /* Minimum unsigned value for equality is VAL & CST2
4690 (should be equal to VAL, otherwise we probably should
4691 have folded the comparison into false) and
4692 maximum unsigned value is VAL | ~CST2. */
4693 maxv
= double_int_ior (valv
, double_int_not (cst2v
));
4694 maxv
= double_int_zext (maxv
, prec
);
4698 tem
= double_int_ior (valv
, double_int_not (cst2v
));
4699 tem
= double_int_zext (tem
, prec
);
4700 /* If VAL is 0, handle (X & CST2) != 0 as (X & CST2) > 0U. */
4701 if (double_int_zero_p (valv
))
4704 sgnbit
= double_int_zero
;
4707 /* If (VAL | ~CST2) is all ones, handle it as
4708 (X & CST2) < VAL. */
4709 if (double_int_equal_p (tem
, double_int_mask (prec
)))
4713 sgnbit
= double_int_zero
;
4717 && double_int_negative_p (double_int_sext (cst2v
, prec
)))
4718 sgnbit
= double_int_zext (double_int_lshift (double_int_one
,
4721 if (!double_int_zero_p (sgnbit
))
4723 if (double_int_equal_p (valv
, sgnbit
))
4729 if (double_int_equal_p (tem
, double_int_mask (prec
- 1)))
4735 sgnbit
= double_int_zero
;
4739 /* Minimum unsigned value for >= if (VAL & CST2) == VAL
4740 is VAL and maximum unsigned value is ~0. For signed
4741 comparison, if CST2 doesn't have most significant bit
4742 set, handle it similarly. If CST2 has MSB set,
4743 the minimum is the same, and maximum is ~0U/2. */
4744 if (!double_int_equal_p (minv
, valv
))
4746 /* If (VAL & CST2) != VAL, X & CST2 can't be equal to
4748 minv
= masked_increment (valv
, cst2v
, sgnbit
, prec
);
4749 if (double_int_equal_p (minv
, valv
))
4752 maxv
= double_int_mask (prec
- (cst2n
? 1 : 0));
4757 /* Find out smallest MINV where MINV > VAL
4758 && (MINV & CST2) == MINV, if any. If VAL is signed and
4759 CST2 has MSB set, compute it biased by 1 << (prec - 1). */
4760 minv
= masked_increment (valv
, cst2v
, sgnbit
, prec
);
4761 if (double_int_equal_p (minv
, valv
))
4763 maxv
= double_int_mask (prec
- (cst2n
? 1 : 0));
4767 /* Minimum unsigned value for <= is 0 and maximum
4768 unsigned value is VAL | ~CST2 if (VAL & CST2) == VAL.
4769 Otherwise, find smallest VAL2 where VAL2 > VAL
4770 && (VAL2 & CST2) == VAL2 and use (VAL2 - 1) | ~CST2
4772 For signed comparison, if CST2 doesn't have most
4773 significant bit set, handle it similarly. If CST2 has
4774 MSB set, the maximum is the same and minimum is INT_MIN. */
4775 if (double_int_equal_p (minv
, valv
))
4779 maxv
= masked_increment (valv
, cst2v
, sgnbit
, prec
);
4780 if (double_int_equal_p (maxv
, valv
))
4782 maxv
= double_int_sub (maxv
, double_int_one
);
4784 maxv
= double_int_ior (maxv
, double_int_not (cst2v
));
4785 maxv
= double_int_zext (maxv
, prec
);
4791 /* Minimum unsigned value for < is 0 and maximum
4792 unsigned value is (VAL-1) | ~CST2 if (VAL & CST2) == VAL.
4793 Otherwise, find smallest VAL2 where VAL2 > VAL
4794 && (VAL2 & CST2) == VAL2 and use (VAL2 - 1) | ~CST2
4796 For signed comparison, if CST2 doesn't have most
4797 significant bit set, handle it similarly. If CST2 has
4798 MSB set, the maximum is the same and minimum is INT_MIN. */
4799 if (double_int_equal_p (minv
, valv
))
4801 if (double_int_equal_p (valv
, sgnbit
))
4807 maxv
= masked_increment (valv
, cst2v
, sgnbit
, prec
);
4808 if (double_int_equal_p (maxv
, valv
))
4811 maxv
= double_int_sub (maxv
, double_int_one
);
4812 maxv
= double_int_ior (maxv
, double_int_not (cst2v
));
4813 maxv
= double_int_zext (maxv
, prec
);
4821 && !double_int_equal_p (double_int_zext (double_int_sub (maxv
,
4824 double_int_mask (prec
)))
4826 tree tmp
, new_val
, type
;
4829 for (i
= 0; i
< 2; i
++)
4832 double_int maxv2
= maxv
;
4834 type
= TREE_TYPE (names
[i
]);
4835 if (!TYPE_UNSIGNED (type
))
4837 type
= build_nonstandard_integer_type (prec
, 1);
4838 tmp
= build1 (NOP_EXPR
, type
, names
[i
]);
4840 if (!double_int_zero_p (minv
))
4842 tmp
= build2 (PLUS_EXPR
, type
, tmp
,
4843 double_int_to_tree (type
,
4844 double_int_neg (minv
)));
4845 maxv2
= double_int_sub (maxv
, minv
);
4847 new_val
= double_int_to_tree (type
, maxv2
);
4851 fprintf (dump_file
, "Adding assert for ");
4852 print_generic_expr (dump_file
, names
[i
], 0);
4853 fprintf (dump_file
, " from ");
4854 print_generic_expr (dump_file
, tmp
, 0);
4855 fprintf (dump_file
, "\n");
4858 register_new_assert_for (names
[i
], tmp
, LE_EXPR
,
4859 new_val
, NULL
, e
, bsi
);
4869 /* OP is an operand of a truth value expression which is known to have
4870 a particular value. Register any asserts for OP and for any
4871 operands in OP's defining statement.
4873 If CODE is EQ_EXPR, then we want to register OP is zero (false),
4874 if CODE is NE_EXPR, then we want to register OP is nonzero (true). */
4877 register_edge_assert_for_1 (tree op
, enum tree_code code
,
4878 edge e
, gimple_stmt_iterator bsi
)
4880 bool retval
= false;
4883 enum tree_code rhs_code
;
4885 /* We only care about SSA_NAMEs. */
4886 if (TREE_CODE (op
) != SSA_NAME
)
4889 /* We know that OP will have a zero or nonzero value. If OP is used
4890 more than once go ahead and register an assert for OP.
4892 The FOUND_IN_SUBGRAPH support is not helpful in this situation as
4893 it will always be set for OP (because OP is used in a COND_EXPR in
4895 if (!has_single_use (op
))
4897 val
= build_int_cst (TREE_TYPE (op
), 0);
4898 register_new_assert_for (op
, op
, code
, val
, NULL
, e
, bsi
);
4902 /* Now look at how OP is set. If it's set from a comparison,
4903 a truth operation or some bit operations, then we may be able
4904 to register information about the operands of that assignment. */
4905 op_def
= SSA_NAME_DEF_STMT (op
);
4906 if (gimple_code (op_def
) != GIMPLE_ASSIGN
)
4909 rhs_code
= gimple_assign_rhs_code (op_def
);
4911 if (TREE_CODE_CLASS (rhs_code
) == tcc_comparison
)
4913 bool invert
= (code
== EQ_EXPR
? true : false);
4914 tree op0
= gimple_assign_rhs1 (op_def
);
4915 tree op1
= gimple_assign_rhs2 (op_def
);
4917 if (TREE_CODE (op0
) == SSA_NAME
)
4918 retval
|= register_edge_assert_for_2 (op0
, e
, bsi
, rhs_code
, op0
, op1
,
4920 if (TREE_CODE (op1
) == SSA_NAME
)
4921 retval
|= register_edge_assert_for_2 (op1
, e
, bsi
, rhs_code
, op0
, op1
,
4924 else if ((code
== NE_EXPR
4925 && gimple_assign_rhs_code (op_def
) == BIT_AND_EXPR
)
4927 && gimple_assign_rhs_code (op_def
) == BIT_IOR_EXPR
))
4929 /* Recurse on each operand. */
4930 retval
|= register_edge_assert_for_1 (gimple_assign_rhs1 (op_def
),
4932 retval
|= register_edge_assert_for_1 (gimple_assign_rhs2 (op_def
),
4935 else if (gimple_assign_rhs_code (op_def
) == BIT_NOT_EXPR
4936 && TYPE_PRECISION (TREE_TYPE (gimple_assign_lhs (op_def
))) == 1)
4938 /* Recurse, flipping CODE. */
4939 code
= invert_tree_comparison (code
, false);
4940 retval
|= register_edge_assert_for_1 (gimple_assign_rhs1 (op_def
),
4943 else if (gimple_assign_rhs_code (op_def
) == SSA_NAME
)
4945 /* Recurse through the copy. */
4946 retval
|= register_edge_assert_for_1 (gimple_assign_rhs1 (op_def
),
4949 else if (CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (op_def
)))
4951 /* Recurse through the type conversion. */
4952 retval
|= register_edge_assert_for_1 (gimple_assign_rhs1 (op_def
),
4959 /* Try to register an edge assertion for SSA name NAME on edge E for
4960 the condition COND contributing to the conditional jump pointed to by SI.
4961 Return true if an assertion for NAME could be registered. */
4964 register_edge_assert_for (tree name
, edge e
, gimple_stmt_iterator si
,
4965 enum tree_code cond_code
, tree cond_op0
,
4969 enum tree_code comp_code
;
4970 bool retval
= false;
4971 bool is_else_edge
= (e
->flags
& EDGE_FALSE_VALUE
) != 0;
4973 /* Do not attempt to infer anything in names that flow through
4975 if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (name
))
4978 if (!extract_code_and_val_from_cond_with_ops (name
, cond_code
,
4984 /* Register ASSERT_EXPRs for name. */
4985 retval
|= register_edge_assert_for_2 (name
, e
, si
, cond_code
, cond_op0
,
4986 cond_op1
, is_else_edge
);
4989 /* If COND is effectively an equality test of an SSA_NAME against
4990 the value zero or one, then we may be able to assert values
4991 for SSA_NAMEs which flow into COND. */
4993 /* In the case of NAME == 1 or NAME != 0, for BIT_AND_EXPR defining
4994 statement of NAME we can assert both operands of the BIT_AND_EXPR
4995 have nonzero value. */
4996 if (((comp_code
== EQ_EXPR
&& integer_onep (val
))
4997 || (comp_code
== NE_EXPR
&& integer_zerop (val
))))
4999 gimple def_stmt
= SSA_NAME_DEF_STMT (name
);
5001 if (is_gimple_assign (def_stmt
)
5002 && gimple_assign_rhs_code (def_stmt
) == BIT_AND_EXPR
)
5004 tree op0
= gimple_assign_rhs1 (def_stmt
);
5005 tree op1
= gimple_assign_rhs2 (def_stmt
);
5006 retval
|= register_edge_assert_for_1 (op0
, NE_EXPR
, e
, si
);
5007 retval
|= register_edge_assert_for_1 (op1
, NE_EXPR
, e
, si
);
5011 /* In the case of NAME == 0 or NAME != 1, for BIT_IOR_EXPR defining
5012 statement of NAME we can assert both operands of the BIT_IOR_EXPR
5014 if (((comp_code
== EQ_EXPR
&& integer_zerop (val
))
5015 || (comp_code
== NE_EXPR
&& integer_onep (val
))))
5017 gimple def_stmt
= SSA_NAME_DEF_STMT (name
);
5019 /* For BIT_IOR_EXPR only if NAME == 0 both operands have
5020 necessarily zero value, or if type-precision is one. */
5021 if (is_gimple_assign (def_stmt
)
5022 && (gimple_assign_rhs_code (def_stmt
) == BIT_IOR_EXPR
5023 && (TYPE_PRECISION (TREE_TYPE (name
)) == 1
5024 || comp_code
== EQ_EXPR
)))
5026 tree op0
= gimple_assign_rhs1 (def_stmt
);
5027 tree op1
= gimple_assign_rhs2 (def_stmt
);
5028 retval
|= register_edge_assert_for_1 (op0
, EQ_EXPR
, e
, si
);
5029 retval
|= register_edge_assert_for_1 (op1
, EQ_EXPR
, e
, si
);
5037 /* Determine whether the outgoing edges of BB should receive an
5038 ASSERT_EXPR for each of the operands of BB's LAST statement.
5039 The last statement of BB must be a COND_EXPR.
5041 If any of the sub-graphs rooted at BB have an interesting use of
5042 the predicate operands, an assert location node is added to the
5043 list of assertions for the corresponding operands. */
5046 find_conditional_asserts (basic_block bb
, gimple last
)
5049 gimple_stmt_iterator bsi
;
5055 need_assert
= false;
5056 bsi
= gsi_for_stmt (last
);
5058 /* Look for uses of the operands in each of the sub-graphs
5059 rooted at BB. We need to check each of the outgoing edges
5060 separately, so that we know what kind of ASSERT_EXPR to
5062 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
5067 /* Register the necessary assertions for each operand in the
5068 conditional predicate. */
5069 FOR_EACH_SSA_TREE_OPERAND (op
, last
, iter
, SSA_OP_USE
)
5071 need_assert
|= register_edge_assert_for (op
, e
, bsi
,
5072 gimple_cond_code (last
),
5073 gimple_cond_lhs (last
),
5074 gimple_cond_rhs (last
));
5087 /* Compare two case labels sorting first by the destination bb index
5088 and then by the case value. */
5091 compare_case_labels (const void *p1
, const void *p2
)
5093 const struct case_info
*ci1
= (const struct case_info
*) p1
;
5094 const struct case_info
*ci2
= (const struct case_info
*) p2
;
5095 int idx1
= ci1
->bb
->index
;
5096 int idx2
= ci2
->bb
->index
;
5100 else if (idx1
== idx2
)
5102 /* Make sure the default label is first in a group. */
5103 if (!CASE_LOW (ci1
->expr
))
5105 else if (!CASE_LOW (ci2
->expr
))
5108 return tree_int_cst_compare (CASE_LOW (ci1
->expr
),
5109 CASE_LOW (ci2
->expr
));
5115 /* Determine whether the outgoing edges of BB should receive an
5116 ASSERT_EXPR for each of the operands of BB's LAST statement.
5117 The last statement of BB must be a SWITCH_EXPR.
5119 If any of the sub-graphs rooted at BB have an interesting use of
5120 the predicate operands, an assert location node is added to the
5121 list of assertions for the corresponding operands. */
5124 find_switch_asserts (basic_block bb
, gimple last
)
5127 gimple_stmt_iterator bsi
;
5130 struct case_info
*ci
;
5131 size_t n
= gimple_switch_num_labels (last
);
5132 #if GCC_VERSION >= 4000
5135 /* Work around GCC 3.4 bug (PR 37086). */
5136 volatile unsigned int idx
;
5139 need_assert
= false;
5140 bsi
= gsi_for_stmt (last
);
5141 op
= gimple_switch_index (last
);
5142 if (TREE_CODE (op
) != SSA_NAME
)
5145 /* Build a vector of case labels sorted by destination label. */
5146 ci
= XNEWVEC (struct case_info
, n
);
5147 for (idx
= 0; idx
< n
; ++idx
)
5149 ci
[idx
].expr
= gimple_switch_label (last
, idx
);
5150 ci
[idx
].bb
= label_to_block (CASE_LABEL (ci
[idx
].expr
));
5152 qsort (ci
, n
, sizeof (struct case_info
), compare_case_labels
);
5154 for (idx
= 0; idx
< n
; ++idx
)
5157 tree cl
= ci
[idx
].expr
;
5158 basic_block cbb
= ci
[idx
].bb
;
5160 min
= CASE_LOW (cl
);
5161 max
= CASE_HIGH (cl
);
5163 /* If there are multiple case labels with the same destination
5164 we need to combine them to a single value range for the edge. */
5165 if (idx
+ 1 < n
&& cbb
== ci
[idx
+ 1].bb
)
5167 /* Skip labels until the last of the group. */
5170 } while (idx
< n
&& cbb
== ci
[idx
].bb
);
5173 /* Pick up the maximum of the case label range. */
5174 if (CASE_HIGH (ci
[idx
].expr
))
5175 max
= CASE_HIGH (ci
[idx
].expr
);
5177 max
= CASE_LOW (ci
[idx
].expr
);
5180 /* Nothing to do if the range includes the default label until we
5181 can register anti-ranges. */
5182 if (min
== NULL_TREE
)
5185 /* Find the edge to register the assert expr on. */
5186 e
= find_edge (bb
, cbb
);
5188 /* Register the necessary assertions for the operand in the
5190 need_assert
|= register_edge_assert_for (op
, e
, bsi
,
5191 max
? GE_EXPR
: EQ_EXPR
,
5193 fold_convert (TREE_TYPE (op
),
5197 need_assert
|= register_edge_assert_for (op
, e
, bsi
, LE_EXPR
,
5199 fold_convert (TREE_TYPE (op
),
5209 /* Traverse all the statements in block BB looking for statements that
5210 may generate useful assertions for the SSA names in their operand.
5211 If a statement produces a useful assertion A for name N_i, then the
5212 list of assertions already generated for N_i is scanned to
5213 determine if A is actually needed.
5215 If N_i already had the assertion A at a location dominating the
5216 current location, then nothing needs to be done. Otherwise, the
5217 new location for A is recorded instead.
5219 1- For every statement S in BB, all the variables used by S are
5220 added to bitmap FOUND_IN_SUBGRAPH.
5222 2- If statement S uses an operand N in a way that exposes a known
5223 value range for N, then if N was not already generated by an
5224 ASSERT_EXPR, create a new assert location for N. For instance,
5225 if N is a pointer and the statement dereferences it, we can
5226 assume that N is not NULL.
5228 3- COND_EXPRs are a special case of #2. We can derive range
5229 information from the predicate but need to insert different
5230 ASSERT_EXPRs for each of the sub-graphs rooted at the
5231 conditional block. If the last statement of BB is a conditional
5232 expression of the form 'X op Y', then
5234 a) Remove X and Y from the set FOUND_IN_SUBGRAPH.
5236 b) If the conditional is the only entry point to the sub-graph
5237 corresponding to the THEN_CLAUSE, recurse into it. On
5238 return, if X and/or Y are marked in FOUND_IN_SUBGRAPH, then
5239 an ASSERT_EXPR is added for the corresponding variable.
5241 c) Repeat step (b) on the ELSE_CLAUSE.
5243 d) Mark X and Y in FOUND_IN_SUBGRAPH.
5252 In this case, an assertion on the THEN clause is useful to
5253 determine that 'a' is always 9 on that edge. However, an assertion
5254 on the ELSE clause would be unnecessary.
5256 4- If BB does not end in a conditional expression, then we recurse
5257 into BB's dominator children.
5259 At the end of the recursive traversal, every SSA name will have a
5260 list of locations where ASSERT_EXPRs should be added. When a new
5261 location for name N is found, it is registered by calling
5262 register_new_assert_for. That function keeps track of all the
5263 registered assertions to prevent adding unnecessary assertions.
5264 For instance, if a pointer P_4 is dereferenced more than once in a
5265 dominator tree, only the location dominating all the dereference of
5266 P_4 will receive an ASSERT_EXPR.
5268 If this function returns true, then it means that there are names
5269 for which we need to generate ASSERT_EXPRs. Those assertions are
5270 inserted by process_assert_insertions. */
5273 find_assert_locations_1 (basic_block bb
, sbitmap live
)
5275 gimple_stmt_iterator si
;
5280 need_assert
= false;
5281 last
= last_stmt (bb
);
5283 /* If BB's last statement is a conditional statement involving integer
5284 operands, determine if we need to add ASSERT_EXPRs. */
5286 && gimple_code (last
) == GIMPLE_COND
5287 && !fp_predicate (last
)
5288 && !ZERO_SSA_OPERANDS (last
, SSA_OP_USE
))
5289 need_assert
|= find_conditional_asserts (bb
, last
);
5291 /* If BB's last statement is a switch statement involving integer
5292 operands, determine if we need to add ASSERT_EXPRs. */
5294 && gimple_code (last
) == GIMPLE_SWITCH
5295 && !ZERO_SSA_OPERANDS (last
, SSA_OP_USE
))
5296 need_assert
|= find_switch_asserts (bb
, last
);
5298 /* Traverse all the statements in BB marking used names and looking
5299 for statements that may infer assertions for their used operands. */
5300 for (si
= gsi_start_bb (bb
); !gsi_end_p (si
); gsi_next (&si
))
5306 stmt
= gsi_stmt (si
);
5308 if (is_gimple_debug (stmt
))
5311 /* See if we can derive an assertion for any of STMT's operands. */
5312 FOR_EACH_SSA_TREE_OPERAND (op
, stmt
, i
, SSA_OP_USE
)
5315 enum tree_code comp_code
;
5317 /* Mark OP in our live bitmap. */
5318 SET_BIT (live
, SSA_NAME_VERSION (op
));
5320 /* If OP is used in such a way that we can infer a value
5321 range for it, and we don't find a previous assertion for
5322 it, create a new assertion location node for OP. */
5323 if (infer_value_range (stmt
, op
, &comp_code
, &value
))
5325 /* If we are able to infer a nonzero value range for OP,
5326 then walk backwards through the use-def chain to see if OP
5327 was set via a typecast.
5329 If so, then we can also infer a nonzero value range
5330 for the operand of the NOP_EXPR. */
5331 if (comp_code
== NE_EXPR
&& integer_zerop (value
))
5334 gimple def_stmt
= SSA_NAME_DEF_STMT (t
);
5336 while (is_gimple_assign (def_stmt
)
5337 && gimple_assign_rhs_code (def_stmt
) == NOP_EXPR
5339 (gimple_assign_rhs1 (def_stmt
)) == SSA_NAME
5341 (TREE_TYPE (gimple_assign_rhs1 (def_stmt
))))
5343 t
= gimple_assign_rhs1 (def_stmt
);
5344 def_stmt
= SSA_NAME_DEF_STMT (t
);
5346 /* Note we want to register the assert for the
5347 operand of the NOP_EXPR after SI, not after the
5349 if (! has_single_use (t
))
5351 register_new_assert_for (t
, t
, comp_code
, value
,
5358 /* If OP is used only once, namely in this STMT, don't
5359 bother creating an ASSERT_EXPR for it. Such an
5360 ASSERT_EXPR would do nothing but increase compile time. */
5361 if (!has_single_use (op
))
5363 register_new_assert_for (op
, op
, comp_code
, value
,
5371 /* Traverse all PHI nodes in BB marking used operands. */
5372 for (si
= gsi_start_phis (bb
); !gsi_end_p(si
); gsi_next (&si
))
5374 use_operand_p arg_p
;
5376 phi
= gsi_stmt (si
);
5378 FOR_EACH_PHI_ARG (arg_p
, phi
, i
, SSA_OP_USE
)
5380 tree arg
= USE_FROM_PTR (arg_p
);
5381 if (TREE_CODE (arg
) == SSA_NAME
)
5382 SET_BIT (live
, SSA_NAME_VERSION (arg
));
5389 /* Do an RPO walk over the function computing SSA name liveness
5390 on-the-fly and deciding on assert expressions to insert.
5391 Returns true if there are assert expressions to be inserted. */
5394 find_assert_locations (void)
5396 int *rpo
= XCNEWVEC (int, last_basic_block
+ NUM_FIXED_BLOCKS
);
5397 int *bb_rpo
= XCNEWVEC (int, last_basic_block
+ NUM_FIXED_BLOCKS
);
5398 int *last_rpo
= XCNEWVEC (int, last_basic_block
+ NUM_FIXED_BLOCKS
);
5402 live
= XCNEWVEC (sbitmap
, last_basic_block
+ NUM_FIXED_BLOCKS
);
5403 rpo_cnt
= pre_and_rev_post_order_compute (NULL
, rpo
, false);
5404 for (i
= 0; i
< rpo_cnt
; ++i
)
5407 need_asserts
= false;
5408 for (i
= rpo_cnt
-1; i
>= 0; --i
)
5410 basic_block bb
= BASIC_BLOCK (rpo
[i
]);
5416 live
[rpo
[i
]] = sbitmap_alloc (num_ssa_names
);
5417 sbitmap_zero (live
[rpo
[i
]]);
5420 /* Process BB and update the live information with uses in
5422 need_asserts
|= find_assert_locations_1 (bb
, live
[rpo
[i
]]);
5424 /* Merge liveness into the predecessor blocks and free it. */
5425 if (!sbitmap_empty_p (live
[rpo
[i
]]))
5428 FOR_EACH_EDGE (e
, ei
, bb
->preds
)
5430 int pred
= e
->src
->index
;
5431 if (e
->flags
& EDGE_DFS_BACK
)
5436 live
[pred
] = sbitmap_alloc (num_ssa_names
);
5437 sbitmap_zero (live
[pred
]);
5439 sbitmap_a_or_b (live
[pred
], live
[pred
], live
[rpo
[i
]]);
5441 if (bb_rpo
[pred
] < pred_rpo
)
5442 pred_rpo
= bb_rpo
[pred
];
5445 /* Record the RPO number of the last visited block that needs
5446 live information from this block. */
5447 last_rpo
[rpo
[i
]] = pred_rpo
;
5451 sbitmap_free (live
[rpo
[i
]]);
5452 live
[rpo
[i
]] = NULL
;
5455 /* We can free all successors live bitmaps if all their
5456 predecessors have been visited already. */
5457 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
5458 if (last_rpo
[e
->dest
->index
] == i
5459 && live
[e
->dest
->index
])
5461 sbitmap_free (live
[e
->dest
->index
]);
5462 live
[e
->dest
->index
] = NULL
;
5467 XDELETEVEC (bb_rpo
);
5468 XDELETEVEC (last_rpo
);
5469 for (i
= 0; i
< last_basic_block
+ NUM_FIXED_BLOCKS
; ++i
)
5471 sbitmap_free (live
[i
]);
5474 return need_asserts
;
5477 /* Create an ASSERT_EXPR for NAME and insert it in the location
5478 indicated by LOC. Return true if we made any edge insertions. */
5481 process_assert_insertions_for (tree name
, assert_locus_t loc
)
5483 /* Build the comparison expression NAME_i COMP_CODE VAL. */
5490 /* If we have X <=> X do not insert an assert expr for that. */
5491 if (loc
->expr
== loc
->val
)
5494 cond
= build2 (loc
->comp_code
, boolean_type_node
, loc
->expr
, loc
->val
);
5495 assert_stmt
= build_assert_expr_for (cond
, name
);
5498 /* We have been asked to insert the assertion on an edge. This
5499 is used only by COND_EXPR and SWITCH_EXPR assertions. */
5500 gcc_checking_assert (gimple_code (gsi_stmt (loc
->si
)) == GIMPLE_COND
5501 || (gimple_code (gsi_stmt (loc
->si
))
5504 gsi_insert_on_edge (loc
->e
, assert_stmt
);
5508 /* Otherwise, we can insert right after LOC->SI iff the
5509 statement must not be the last statement in the block. */
5510 stmt
= gsi_stmt (loc
->si
);
5511 if (!stmt_ends_bb_p (stmt
))
5513 gsi_insert_after (&loc
->si
, assert_stmt
, GSI_SAME_STMT
);
5517 /* If STMT must be the last statement in BB, we can only insert new
5518 assertions on the non-abnormal edge out of BB. Note that since
5519 STMT is not control flow, there may only be one non-abnormal edge
5521 FOR_EACH_EDGE (e
, ei
, loc
->bb
->succs
)
5522 if (!(e
->flags
& EDGE_ABNORMAL
))
5524 gsi_insert_on_edge (e
, assert_stmt
);
5532 /* Process all the insertions registered for every name N_i registered
5533 in NEED_ASSERT_FOR. The list of assertions to be inserted are
5534 found in ASSERTS_FOR[i]. */
5537 process_assert_insertions (void)
5541 bool update_edges_p
= false;
5542 int num_asserts
= 0;
5544 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
5545 dump_all_asserts (dump_file
);
5547 EXECUTE_IF_SET_IN_BITMAP (need_assert_for
, 0, i
, bi
)
5549 assert_locus_t loc
= asserts_for
[i
];
5554 assert_locus_t next
= loc
->next
;
5555 update_edges_p
|= process_assert_insertions_for (ssa_name (i
), loc
);
5563 gsi_commit_edge_inserts ();
5565 statistics_counter_event (cfun
, "Number of ASSERT_EXPR expressions inserted",
5570 /* Traverse the flowgraph looking for conditional jumps to insert range
5571 expressions. These range expressions are meant to provide information
5572 to optimizations that need to reason in terms of value ranges. They
5573 will not be expanded into RTL. For instance, given:
5582 this pass will transform the code into:
5588 x = ASSERT_EXPR <x, x < y>
5593 y = ASSERT_EXPR <y, x <= y>
5597 The idea is that once copy and constant propagation have run, other
5598 optimizations will be able to determine what ranges of values can 'x'
5599 take in different paths of the code, simply by checking the reaching
5600 definition of 'x'. */
5603 insert_range_assertions (void)
5605 need_assert_for
= BITMAP_ALLOC (NULL
);
5606 asserts_for
= XCNEWVEC (assert_locus_t
, num_ssa_names
);
5608 calculate_dominance_info (CDI_DOMINATORS
);
5610 if (find_assert_locations ())
5612 process_assert_insertions ();
5613 update_ssa (TODO_update_ssa_no_phi
);
5616 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
5618 fprintf (dump_file
, "\nSSA form after inserting ASSERT_EXPRs\n");
5619 dump_function_to_file (current_function_decl
, dump_file
, dump_flags
);
5623 BITMAP_FREE (need_assert_for
);
5626 /* Checks one ARRAY_REF in REF, located at LOCUS. Ignores flexible arrays
5627 and "struct" hacks. If VRP can determine that the
5628 array subscript is a constant, check if it is outside valid
5629 range. If the array subscript is a RANGE, warn if it is
5630 non-overlapping with valid range.
5631 IGNORE_OFF_BY_ONE is true if the ARRAY_REF is inside a ADDR_EXPR. */
5634 check_array_ref (location_t location
, tree ref
, bool ignore_off_by_one
)
5636 value_range_t
* vr
= NULL
;
5637 tree low_sub
, up_sub
;
5638 tree low_bound
, up_bound
, up_bound_p1
;
5641 if (TREE_NO_WARNING (ref
))
5644 low_sub
= up_sub
= TREE_OPERAND (ref
, 1);
5645 up_bound
= array_ref_up_bound (ref
);
5647 /* Can not check flexible arrays. */
5649 || TREE_CODE (up_bound
) != INTEGER_CST
)
5652 /* Accesses to trailing arrays via pointers may access storage
5653 beyond the types array bounds. */
5654 base
= get_base_address (ref
);
5655 if (base
&& TREE_CODE (base
) == MEM_REF
)
5657 tree cref
, next
= NULL_TREE
;
5659 if (TREE_CODE (TREE_OPERAND (ref
, 0)) != COMPONENT_REF
)
5662 cref
= TREE_OPERAND (ref
, 0);
5663 if (TREE_CODE (TREE_TYPE (TREE_OPERAND (cref
, 0))) == RECORD_TYPE
)
5664 for (next
= DECL_CHAIN (TREE_OPERAND (cref
, 1));
5665 next
&& TREE_CODE (next
) != FIELD_DECL
;
5666 next
= DECL_CHAIN (next
))
5669 /* If this is the last field in a struct type or a field in a
5670 union type do not warn. */
5675 low_bound
= array_ref_low_bound (ref
);
5676 up_bound_p1
= int_const_binop (PLUS_EXPR
, up_bound
, integer_one_node
);
5678 if (TREE_CODE (low_sub
) == SSA_NAME
)
5680 vr
= get_value_range (low_sub
);
5681 if (vr
->type
== VR_RANGE
|| vr
->type
== VR_ANTI_RANGE
)
5683 low_sub
= vr
->type
== VR_RANGE
? vr
->max
: vr
->min
;
5684 up_sub
= vr
->type
== VR_RANGE
? vr
->min
: vr
->max
;
5688 if (vr
&& vr
->type
== VR_ANTI_RANGE
)
5690 if (TREE_CODE (up_sub
) == INTEGER_CST
5691 && tree_int_cst_lt (up_bound
, up_sub
)
5692 && TREE_CODE (low_sub
) == INTEGER_CST
5693 && tree_int_cst_lt (low_sub
, low_bound
))
5695 warning_at (location
, OPT_Warray_bounds
,
5696 "array subscript is outside array bounds");
5697 TREE_NO_WARNING (ref
) = 1;
5700 else if (TREE_CODE (up_sub
) == INTEGER_CST
5701 && (ignore_off_by_one
5702 ? (tree_int_cst_lt (up_bound
, up_sub
)
5703 && !tree_int_cst_equal (up_bound_p1
, up_sub
))
5704 : (tree_int_cst_lt (up_bound
, up_sub
)
5705 || tree_int_cst_equal (up_bound_p1
, up_sub
))))
5707 warning_at (location
, OPT_Warray_bounds
,
5708 "array subscript is above array bounds");
5709 TREE_NO_WARNING (ref
) = 1;
5711 else if (TREE_CODE (low_sub
) == INTEGER_CST
5712 && tree_int_cst_lt (low_sub
, low_bound
))
5714 warning_at (location
, OPT_Warray_bounds
,
5715 "array subscript is below array bounds");
5716 TREE_NO_WARNING (ref
) = 1;
5720 /* Searches if the expr T, located at LOCATION computes
5721 address of an ARRAY_REF, and call check_array_ref on it. */
5724 search_for_addr_array (tree t
, location_t location
)
5726 while (TREE_CODE (t
) == SSA_NAME
)
5728 gimple g
= SSA_NAME_DEF_STMT (t
);
5730 if (gimple_code (g
) != GIMPLE_ASSIGN
)
5733 if (get_gimple_rhs_class (gimple_assign_rhs_code (g
))
5734 != GIMPLE_SINGLE_RHS
)
5737 t
= gimple_assign_rhs1 (g
);
5741 /* We are only interested in addresses of ARRAY_REF's. */
5742 if (TREE_CODE (t
) != ADDR_EXPR
)
5745 /* Check each ARRAY_REFs in the reference chain. */
5748 if (TREE_CODE (t
) == ARRAY_REF
)
5749 check_array_ref (location
, t
, true /*ignore_off_by_one*/);
5751 t
= TREE_OPERAND (t
, 0);
5753 while (handled_component_p (t
));
5755 if (TREE_CODE (t
) == MEM_REF
5756 && TREE_CODE (TREE_OPERAND (t
, 0)) == ADDR_EXPR
5757 && !TREE_NO_WARNING (t
))
5759 tree tem
= TREE_OPERAND (TREE_OPERAND (t
, 0), 0);
5760 tree low_bound
, up_bound
, el_sz
;
5762 if (TREE_CODE (TREE_TYPE (tem
)) != ARRAY_TYPE
5763 || TREE_CODE (TREE_TYPE (TREE_TYPE (tem
))) == ARRAY_TYPE
5764 || !TYPE_DOMAIN (TREE_TYPE (tem
)))
5767 low_bound
= TYPE_MIN_VALUE (TYPE_DOMAIN (TREE_TYPE (tem
)));
5768 up_bound
= TYPE_MAX_VALUE (TYPE_DOMAIN (TREE_TYPE (tem
)));
5769 el_sz
= TYPE_SIZE_UNIT (TREE_TYPE (TREE_TYPE (tem
)));
5771 || TREE_CODE (low_bound
) != INTEGER_CST
5773 || TREE_CODE (up_bound
) != INTEGER_CST
5775 || TREE_CODE (el_sz
) != INTEGER_CST
)
5778 idx
= mem_ref_offset (t
);
5779 idx
= double_int_sdiv (idx
, tree_to_double_int (el_sz
), TRUNC_DIV_EXPR
);
5780 if (double_int_scmp (idx
, double_int_zero
) < 0)
5782 warning_at (location
, OPT_Warray_bounds
,
5783 "array subscript is below array bounds");
5784 TREE_NO_WARNING (t
) = 1;
5786 else if (double_int_scmp (idx
,
5789 (tree_to_double_int (up_bound
),
5791 (tree_to_double_int (low_bound
))),
5792 double_int_one
)) > 0)
5794 warning_at (location
, OPT_Warray_bounds
,
5795 "array subscript is above array bounds");
5796 TREE_NO_WARNING (t
) = 1;
5801 /* walk_tree() callback that checks if *TP is
5802 an ARRAY_REF inside an ADDR_EXPR (in which an array
5803 subscript one outside the valid range is allowed). Call
5804 check_array_ref for each ARRAY_REF found. The location is
5808 check_array_bounds (tree
*tp
, int *walk_subtree
, void *data
)
5811 struct walk_stmt_info
*wi
= (struct walk_stmt_info
*) data
;
5812 location_t location
;
5814 if (EXPR_HAS_LOCATION (t
))
5815 location
= EXPR_LOCATION (t
);
5818 location_t
*locp
= (location_t
*) wi
->info
;
5822 *walk_subtree
= TRUE
;
5824 if (TREE_CODE (t
) == ARRAY_REF
)
5825 check_array_ref (location
, t
, false /*ignore_off_by_one*/);
5827 if (TREE_CODE (t
) == MEM_REF
5828 || (TREE_CODE (t
) == RETURN_EXPR
&& TREE_OPERAND (t
, 0)))
5829 search_for_addr_array (TREE_OPERAND (t
, 0), location
);
5831 if (TREE_CODE (t
) == ADDR_EXPR
)
5832 *walk_subtree
= FALSE
;
5837 /* Walk over all statements of all reachable BBs and call check_array_bounds
5841 check_all_array_refs (void)
5844 gimple_stmt_iterator si
;
5850 bool executable
= false;
5852 /* Skip blocks that were found to be unreachable. */
5853 FOR_EACH_EDGE (e
, ei
, bb
->preds
)
5854 executable
|= !!(e
->flags
& EDGE_EXECUTABLE
);
5858 for (si
= gsi_start_bb (bb
); !gsi_end_p (si
); gsi_next (&si
))
5860 gimple stmt
= gsi_stmt (si
);
5861 struct walk_stmt_info wi
;
5862 if (!gimple_has_location (stmt
))
5865 if (is_gimple_call (stmt
))
5868 size_t n
= gimple_call_num_args (stmt
);
5869 for (i
= 0; i
< n
; i
++)
5871 tree arg
= gimple_call_arg (stmt
, i
);
5872 search_for_addr_array (arg
, gimple_location (stmt
));
5877 memset (&wi
, 0, sizeof (wi
));
5878 wi
.info
= CONST_CAST (void *, (const void *)
5879 gimple_location_ptr (stmt
));
5881 walk_gimple_op (gsi_stmt (si
),
5889 /* Convert range assertion expressions into the implied copies and
5890 copy propagate away the copies. Doing the trivial copy propagation
5891 here avoids the need to run the full copy propagation pass after
5894 FIXME, this will eventually lead to copy propagation removing the
5895 names that had useful range information attached to them. For
5896 instance, if we had the assertion N_i = ASSERT_EXPR <N_j, N_j > 3>,
5897 then N_i will have the range [3, +INF].
5899 However, by converting the assertion into the implied copy
5900 operation N_i = N_j, we will then copy-propagate N_j into the uses
5901 of N_i and lose the range information. We may want to hold on to
5902 ASSERT_EXPRs a little while longer as the ranges could be used in
5903 things like jump threading.
5905 The problem with keeping ASSERT_EXPRs around is that passes after
5906 VRP need to handle them appropriately.
5908 Another approach would be to make the range information a first
5909 class property of the SSA_NAME so that it can be queried from
5910 any pass. This is made somewhat more complex by the need for
5911 multiple ranges to be associated with one SSA_NAME. */
5914 remove_range_assertions (void)
5917 gimple_stmt_iterator si
;
5919 /* Note that the BSI iterator bump happens at the bottom of the
5920 loop and no bump is necessary if we're removing the statement
5921 referenced by the current BSI. */
5923 for (si
= gsi_start_bb (bb
); !gsi_end_p (si
);)
5925 gimple stmt
= gsi_stmt (si
);
5928 if (is_gimple_assign (stmt
)
5929 && gimple_assign_rhs_code (stmt
) == ASSERT_EXPR
)
5931 tree rhs
= gimple_assign_rhs1 (stmt
);
5933 tree cond
= fold (ASSERT_EXPR_COND (rhs
));
5934 use_operand_p use_p
;
5935 imm_use_iterator iter
;
5937 gcc_assert (cond
!= boolean_false_node
);
5939 /* Propagate the RHS into every use of the LHS. */
5940 var
= ASSERT_EXPR_VAR (rhs
);
5941 FOR_EACH_IMM_USE_STMT (use_stmt
, iter
,
5942 gimple_assign_lhs (stmt
))
5943 FOR_EACH_IMM_USE_ON_STMT (use_p
, iter
)
5945 SET_USE (use_p
, var
);
5946 gcc_assert (TREE_CODE (var
) == SSA_NAME
);
5949 /* And finally, remove the copy, it is not needed. */
5950 gsi_remove (&si
, true);
5951 release_defs (stmt
);
5959 /* Return true if STMT is interesting for VRP. */
5962 stmt_interesting_for_vrp (gimple stmt
)
5964 if (gimple_code (stmt
) == GIMPLE_PHI
5965 && is_gimple_reg (gimple_phi_result (stmt
))
5966 && (INTEGRAL_TYPE_P (TREE_TYPE (gimple_phi_result (stmt
)))
5967 || POINTER_TYPE_P (TREE_TYPE (gimple_phi_result (stmt
)))))
5969 else if (is_gimple_assign (stmt
) || is_gimple_call (stmt
))
5971 tree lhs
= gimple_get_lhs (stmt
);
5973 /* In general, assignments with virtual operands are not useful
5974 for deriving ranges, with the obvious exception of calls to
5975 builtin functions. */
5976 if (lhs
&& TREE_CODE (lhs
) == SSA_NAME
5977 && (INTEGRAL_TYPE_P (TREE_TYPE (lhs
))
5978 || POINTER_TYPE_P (TREE_TYPE (lhs
)))
5979 && ((is_gimple_call (stmt
)
5980 && gimple_call_fndecl (stmt
) != NULL_TREE
5981 && DECL_BUILT_IN (gimple_call_fndecl (stmt
)))
5982 || !gimple_vuse (stmt
)))
5985 else if (gimple_code (stmt
) == GIMPLE_COND
5986 || gimple_code (stmt
) == GIMPLE_SWITCH
)
5993 /* Initialize local data structures for VRP. */
5996 vrp_initialize (void)
6000 values_propagated
= false;
6001 num_vr_values
= num_ssa_names
;
6002 vr_value
= XCNEWVEC (value_range_t
*, num_vr_values
);
6003 vr_phi_edge_counts
= XCNEWVEC (int, num_ssa_names
);
6007 gimple_stmt_iterator si
;
6009 for (si
= gsi_start_phis (bb
); !gsi_end_p (si
); gsi_next (&si
))
6011 gimple phi
= gsi_stmt (si
);
6012 if (!stmt_interesting_for_vrp (phi
))
6014 tree lhs
= PHI_RESULT (phi
);
6015 set_value_range_to_varying (get_value_range (lhs
));
6016 prop_set_simulate_again (phi
, false);
6019 prop_set_simulate_again (phi
, true);
6022 for (si
= gsi_start_bb (bb
); !gsi_end_p (si
); gsi_next (&si
))
6024 gimple stmt
= gsi_stmt (si
);
6026 /* If the statement is a control insn, then we do not
6027 want to avoid simulating the statement once. Failure
6028 to do so means that those edges will never get added. */
6029 if (stmt_ends_bb_p (stmt
))
6030 prop_set_simulate_again (stmt
, true);
6031 else if (!stmt_interesting_for_vrp (stmt
))
6035 FOR_EACH_SSA_TREE_OPERAND (def
, stmt
, i
, SSA_OP_DEF
)
6036 set_value_range_to_varying (get_value_range (def
));
6037 prop_set_simulate_again (stmt
, false);
6040 prop_set_simulate_again (stmt
, true);
6045 /* Return the singleton value-range for NAME or NAME. */
6048 vrp_valueize (tree name
)
6050 if (TREE_CODE (name
) == SSA_NAME
)
6052 value_range_t
*vr
= get_value_range (name
);
6053 if (vr
->type
== VR_RANGE
6054 && (vr
->min
== vr
->max
6055 || operand_equal_p (vr
->min
, vr
->max
, 0)))
6061 /* Visit assignment STMT. If it produces an interesting range, record
6062 the SSA name in *OUTPUT_P. */
6064 static enum ssa_prop_result
6065 vrp_visit_assignment_or_call (gimple stmt
, tree
*output_p
)
6069 enum gimple_code code
= gimple_code (stmt
);
6070 lhs
= gimple_get_lhs (stmt
);
6072 /* We only keep track of ranges in integral and pointer types. */
6073 if (TREE_CODE (lhs
) == SSA_NAME
6074 && ((INTEGRAL_TYPE_P (TREE_TYPE (lhs
))
6075 /* It is valid to have NULL MIN/MAX values on a type. See
6076 build_range_type. */
6077 && TYPE_MIN_VALUE (TREE_TYPE (lhs
))
6078 && TYPE_MAX_VALUE (TREE_TYPE (lhs
)))
6079 || POINTER_TYPE_P (TREE_TYPE (lhs
))))
6081 value_range_t new_vr
= { VR_UNDEFINED
, NULL_TREE
, NULL_TREE
, NULL
};
6083 /* Try folding the statement to a constant first. */
6084 tree tem
= gimple_fold_stmt_to_constant (stmt
, vrp_valueize
);
6085 if (tem
&& !is_overflow_infinity (tem
))
6086 set_value_range (&new_vr
, VR_RANGE
, tem
, tem
, NULL
);
6087 /* Then dispatch to value-range extracting functions. */
6088 else if (code
== GIMPLE_CALL
)
6089 extract_range_basic (&new_vr
, stmt
);
6091 extract_range_from_assignment (&new_vr
, stmt
);
6093 if (update_value_range (lhs
, &new_vr
))
6097 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
6099 fprintf (dump_file
, "Found new range for ");
6100 print_generic_expr (dump_file
, lhs
, 0);
6101 fprintf (dump_file
, ": ");
6102 dump_value_range (dump_file
, &new_vr
);
6103 fprintf (dump_file
, "\n\n");
6106 if (new_vr
.type
== VR_VARYING
)
6107 return SSA_PROP_VARYING
;
6109 return SSA_PROP_INTERESTING
;
6112 return SSA_PROP_NOT_INTERESTING
;
6115 /* Every other statement produces no useful ranges. */
6116 FOR_EACH_SSA_TREE_OPERAND (def
, stmt
, iter
, SSA_OP_DEF
)
6117 set_value_range_to_varying (get_value_range (def
));
6119 return SSA_PROP_VARYING
;
6122 /* Helper that gets the value range of the SSA_NAME with version I
6123 or a symbolic range containing the SSA_NAME only if the value range
6124 is varying or undefined. */
6126 static inline value_range_t
6127 get_vr_for_comparison (int i
)
6129 value_range_t vr
= *get_value_range (ssa_name (i
));
6131 /* If name N_i does not have a valid range, use N_i as its own
6132 range. This allows us to compare against names that may
6133 have N_i in their ranges. */
6134 if (vr
.type
== VR_VARYING
|| vr
.type
== VR_UNDEFINED
)
6137 vr
.min
= ssa_name (i
);
6138 vr
.max
= ssa_name (i
);
6144 /* Compare all the value ranges for names equivalent to VAR with VAL
6145 using comparison code COMP. Return the same value returned by
6146 compare_range_with_value, including the setting of
6147 *STRICT_OVERFLOW_P. */
6150 compare_name_with_value (enum tree_code comp
, tree var
, tree val
,
6151 bool *strict_overflow_p
)
6157 int used_strict_overflow
;
6159 value_range_t equiv_vr
;
6161 /* Get the set of equivalences for VAR. */
6162 e
= get_value_range (var
)->equiv
;
6164 /* Start at -1. Set it to 0 if we do a comparison without relying
6165 on overflow, or 1 if all comparisons rely on overflow. */
6166 used_strict_overflow
= -1;
6168 /* Compare vars' value range with val. */
6169 equiv_vr
= get_vr_for_comparison (SSA_NAME_VERSION (var
));
6171 retval
= compare_range_with_value (comp
, &equiv_vr
, val
, &sop
);
6173 used_strict_overflow
= sop
? 1 : 0;
6175 /* If the equiv set is empty we have done all work we need to do. */
6179 && used_strict_overflow
> 0)
6180 *strict_overflow_p
= true;
6184 EXECUTE_IF_SET_IN_BITMAP (e
, 0, i
, bi
)
6186 equiv_vr
= get_vr_for_comparison (i
);
6188 t
= compare_range_with_value (comp
, &equiv_vr
, val
, &sop
);
6191 /* If we get different answers from different members
6192 of the equivalence set this check must be in a dead
6193 code region. Folding it to a trap representation
6194 would be correct here. For now just return don't-know. */
6204 used_strict_overflow
= 0;
6205 else if (used_strict_overflow
< 0)
6206 used_strict_overflow
= 1;
6211 && used_strict_overflow
> 0)
6212 *strict_overflow_p
= true;
6218 /* Given a comparison code COMP and names N1 and N2, compare all the
6219 ranges equivalent to N1 against all the ranges equivalent to N2
6220 to determine the value of N1 COMP N2. Return the same value
6221 returned by compare_ranges. Set *STRICT_OVERFLOW_P to indicate
6222 whether we relied on an overflow infinity in the comparison. */
6226 compare_names (enum tree_code comp
, tree n1
, tree n2
,
6227 bool *strict_overflow_p
)
6231 bitmap_iterator bi1
, bi2
;
6233 int used_strict_overflow
;
6234 static bitmap_obstack
*s_obstack
= NULL
;
6235 static bitmap s_e1
= NULL
, s_e2
= NULL
;
6237 /* Compare the ranges of every name equivalent to N1 against the
6238 ranges of every name equivalent to N2. */
6239 e1
= get_value_range (n1
)->equiv
;
6240 e2
= get_value_range (n2
)->equiv
;
6242 /* Use the fake bitmaps if e1 or e2 are not available. */
6243 if (s_obstack
== NULL
)
6245 s_obstack
= XNEW (bitmap_obstack
);
6246 bitmap_obstack_initialize (s_obstack
);
6247 s_e1
= BITMAP_ALLOC (s_obstack
);
6248 s_e2
= BITMAP_ALLOC (s_obstack
);
6255 /* Add N1 and N2 to their own set of equivalences to avoid
6256 duplicating the body of the loop just to check N1 and N2
6258 bitmap_set_bit (e1
, SSA_NAME_VERSION (n1
));
6259 bitmap_set_bit (e2
, SSA_NAME_VERSION (n2
));
6261 /* If the equivalence sets have a common intersection, then the two
6262 names can be compared without checking their ranges. */
6263 if (bitmap_intersect_p (e1
, e2
))
6265 bitmap_clear_bit (e1
, SSA_NAME_VERSION (n1
));
6266 bitmap_clear_bit (e2
, SSA_NAME_VERSION (n2
));
6268 return (comp
== EQ_EXPR
|| comp
== GE_EXPR
|| comp
== LE_EXPR
)
6270 : boolean_false_node
;
6273 /* Start at -1. Set it to 0 if we do a comparison without relying
6274 on overflow, or 1 if all comparisons rely on overflow. */
6275 used_strict_overflow
= -1;
6277 /* Otherwise, compare all the equivalent ranges. First, add N1 and
6278 N2 to their own set of equivalences to avoid duplicating the body
6279 of the loop just to check N1 and N2 ranges. */
6280 EXECUTE_IF_SET_IN_BITMAP (e1
, 0, i1
, bi1
)
6282 value_range_t vr1
= get_vr_for_comparison (i1
);
6284 t
= retval
= NULL_TREE
;
6285 EXECUTE_IF_SET_IN_BITMAP (e2
, 0, i2
, bi2
)
6289 value_range_t vr2
= get_vr_for_comparison (i2
);
6291 t
= compare_ranges (comp
, &vr1
, &vr2
, &sop
);
6294 /* If we get different answers from different members
6295 of the equivalence set this check must be in a dead
6296 code region. Folding it to a trap representation
6297 would be correct here. For now just return don't-know. */
6301 bitmap_clear_bit (e1
, SSA_NAME_VERSION (n1
));
6302 bitmap_clear_bit (e2
, SSA_NAME_VERSION (n2
));
6308 used_strict_overflow
= 0;
6309 else if (used_strict_overflow
< 0)
6310 used_strict_overflow
= 1;
6316 bitmap_clear_bit (e1
, SSA_NAME_VERSION (n1
));
6317 bitmap_clear_bit (e2
, SSA_NAME_VERSION (n2
));
6318 if (used_strict_overflow
> 0)
6319 *strict_overflow_p
= true;
6324 /* None of the equivalent ranges are useful in computing this
6326 bitmap_clear_bit (e1
, SSA_NAME_VERSION (n1
));
6327 bitmap_clear_bit (e2
, SSA_NAME_VERSION (n2
));
6331 /* Helper function for vrp_evaluate_conditional_warnv. */
6334 vrp_evaluate_conditional_warnv_with_ops_using_ranges (enum tree_code code
,
6336 bool * strict_overflow_p
)
6338 value_range_t
*vr0
, *vr1
;
6340 vr0
= (TREE_CODE (op0
) == SSA_NAME
) ? get_value_range (op0
) : NULL
;
6341 vr1
= (TREE_CODE (op1
) == SSA_NAME
) ? get_value_range (op1
) : NULL
;
6344 return compare_ranges (code
, vr0
, vr1
, strict_overflow_p
);
6345 else if (vr0
&& vr1
== NULL
)
6346 return compare_range_with_value (code
, vr0
, op1
, strict_overflow_p
);
6347 else if (vr0
== NULL
&& vr1
)
6348 return (compare_range_with_value
6349 (swap_tree_comparison (code
), vr1
, op0
, strict_overflow_p
));
6353 /* Helper function for vrp_evaluate_conditional_warnv. */
6356 vrp_evaluate_conditional_warnv_with_ops (enum tree_code code
, tree op0
,
6357 tree op1
, bool use_equiv_p
,
6358 bool *strict_overflow_p
, bool *only_ranges
)
6362 *only_ranges
= true;
6364 /* We only deal with integral and pointer types. */
6365 if (!INTEGRAL_TYPE_P (TREE_TYPE (op0
))
6366 && !POINTER_TYPE_P (TREE_TYPE (op0
)))
6372 && (ret
= vrp_evaluate_conditional_warnv_with_ops_using_ranges
6373 (code
, op0
, op1
, strict_overflow_p
)))
6375 *only_ranges
= false;
6376 if (TREE_CODE (op0
) == SSA_NAME
&& TREE_CODE (op1
) == SSA_NAME
)
6377 return compare_names (code
, op0
, op1
, strict_overflow_p
);
6378 else if (TREE_CODE (op0
) == SSA_NAME
)
6379 return compare_name_with_value (code
, op0
, op1
, strict_overflow_p
);
6380 else if (TREE_CODE (op1
) == SSA_NAME
)
6381 return (compare_name_with_value
6382 (swap_tree_comparison (code
), op1
, op0
, strict_overflow_p
));
6385 return vrp_evaluate_conditional_warnv_with_ops_using_ranges (code
, op0
, op1
,
6390 /* Given (CODE OP0 OP1) within STMT, try to simplify it based on value range
6391 information. Return NULL if the conditional can not be evaluated.
6392 The ranges of all the names equivalent with the operands in COND
6393 will be used when trying to compute the value. If the result is
6394 based on undefined signed overflow, issue a warning if
6398 vrp_evaluate_conditional (enum tree_code code
, tree op0
, tree op1
, gimple stmt
)
6404 /* Some passes and foldings leak constants with overflow flag set
6405 into the IL. Avoid doing wrong things with these and bail out. */
6406 if ((TREE_CODE (op0
) == INTEGER_CST
6407 && TREE_OVERFLOW (op0
))
6408 || (TREE_CODE (op1
) == INTEGER_CST
6409 && TREE_OVERFLOW (op1
)))
6413 ret
= vrp_evaluate_conditional_warnv_with_ops (code
, op0
, op1
, true, &sop
,
6418 enum warn_strict_overflow_code wc
;
6419 const char* warnmsg
;
6421 if (is_gimple_min_invariant (ret
))
6423 wc
= WARN_STRICT_OVERFLOW_CONDITIONAL
;
6424 warnmsg
= G_("assuming signed overflow does not occur when "
6425 "simplifying conditional to constant");
6429 wc
= WARN_STRICT_OVERFLOW_COMPARISON
;
6430 warnmsg
= G_("assuming signed overflow does not occur when "
6431 "simplifying conditional");
6434 if (issue_strict_overflow_warning (wc
))
6436 location_t location
;
6438 if (!gimple_has_location (stmt
))
6439 location
= input_location
;
6441 location
= gimple_location (stmt
);
6442 warning_at (location
, OPT_Wstrict_overflow
, "%s", warnmsg
);
6446 if (warn_type_limits
6447 && ret
&& only_ranges
6448 && TREE_CODE_CLASS (code
) == tcc_comparison
6449 && TREE_CODE (op0
) == SSA_NAME
)
6451 /* If the comparison is being folded and the operand on the LHS
6452 is being compared against a constant value that is outside of
6453 the natural range of OP0's type, then the predicate will
6454 always fold regardless of the value of OP0. If -Wtype-limits
6455 was specified, emit a warning. */
6456 tree type
= TREE_TYPE (op0
);
6457 value_range_t
*vr0
= get_value_range (op0
);
6459 if (vr0
->type
!= VR_VARYING
6460 && INTEGRAL_TYPE_P (type
)
6461 && vrp_val_is_min (vr0
->min
)
6462 && vrp_val_is_max (vr0
->max
)
6463 && is_gimple_min_invariant (op1
))
6465 location_t location
;
6467 if (!gimple_has_location (stmt
))
6468 location
= input_location
;
6470 location
= gimple_location (stmt
);
6472 warning_at (location
, OPT_Wtype_limits
,
6474 ? G_("comparison always false "
6475 "due to limited range of data type")
6476 : G_("comparison always true "
6477 "due to limited range of data type"));
6485 /* Visit conditional statement STMT. If we can determine which edge
6486 will be taken out of STMT's basic block, record it in
6487 *TAKEN_EDGE_P and return SSA_PROP_INTERESTING. Otherwise, return
6488 SSA_PROP_VARYING. */
6490 static enum ssa_prop_result
6491 vrp_visit_cond_stmt (gimple stmt
, edge
*taken_edge_p
)
6496 *taken_edge_p
= NULL
;
6498 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
6503 fprintf (dump_file
, "\nVisiting conditional with predicate: ");
6504 print_gimple_stmt (dump_file
, stmt
, 0, 0);
6505 fprintf (dump_file
, "\nWith known ranges\n");
6507 FOR_EACH_SSA_TREE_OPERAND (use
, stmt
, i
, SSA_OP_USE
)
6509 fprintf (dump_file
, "\t");
6510 print_generic_expr (dump_file
, use
, 0);
6511 fprintf (dump_file
, ": ");
6512 dump_value_range (dump_file
, vr_value
[SSA_NAME_VERSION (use
)]);
6515 fprintf (dump_file
, "\n");
6518 /* Compute the value of the predicate COND by checking the known
6519 ranges of each of its operands.
6521 Note that we cannot evaluate all the equivalent ranges here
6522 because those ranges may not yet be final and with the current
6523 propagation strategy, we cannot determine when the value ranges
6524 of the names in the equivalence set have changed.
6526 For instance, given the following code fragment
6530 i_14 = ASSERT_EXPR <i_5, i_5 != 0>
6534 Assume that on the first visit to i_14, i_5 has the temporary
6535 range [8, 8] because the second argument to the PHI function is
6536 not yet executable. We derive the range ~[0, 0] for i_14 and the
6537 equivalence set { i_5 }. So, when we visit 'if (i_14 == 1)' for
6538 the first time, since i_14 is equivalent to the range [8, 8], we
6539 determine that the predicate is always false.
6541 On the next round of propagation, i_13 is determined to be
6542 VARYING, which causes i_5 to drop down to VARYING. So, another
6543 visit to i_14 is scheduled. In this second visit, we compute the
6544 exact same range and equivalence set for i_14, namely ~[0, 0] and
6545 { i_5 }. But we did not have the previous range for i_5
6546 registered, so vrp_visit_assignment thinks that the range for
6547 i_14 has not changed. Therefore, the predicate 'if (i_14 == 1)'
6548 is not visited again, which stops propagation from visiting
6549 statements in the THEN clause of that if().
6551 To properly fix this we would need to keep the previous range
6552 value for the names in the equivalence set. This way we would've
6553 discovered that from one visit to the other i_5 changed from
6554 range [8, 8] to VR_VARYING.
6556 However, fixing this apparent limitation may not be worth the
6557 additional checking. Testing on several code bases (GCC, DLV,
6558 MICO, TRAMP3D and SPEC2000) showed that doing this results in
6559 4 more predicates folded in SPEC. */
6562 val
= vrp_evaluate_conditional_warnv_with_ops (gimple_cond_code (stmt
),
6563 gimple_cond_lhs (stmt
),
6564 gimple_cond_rhs (stmt
),
6569 *taken_edge_p
= find_taken_edge (gimple_bb (stmt
), val
);
6572 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
6574 "\nIgnoring predicate evaluation because "
6575 "it assumes that signed overflow is undefined");
6580 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
6582 fprintf (dump_file
, "\nPredicate evaluates to: ");
6583 if (val
== NULL_TREE
)
6584 fprintf (dump_file
, "DON'T KNOW\n");
6586 print_generic_stmt (dump_file
, val
, 0);
6589 return (*taken_edge_p
) ? SSA_PROP_INTERESTING
: SSA_PROP_VARYING
;
6592 /* Searches the case label vector VEC for the index *IDX of the CASE_LABEL
6593 that includes the value VAL. The search is restricted to the range
6594 [START_IDX, n - 1] where n is the size of VEC.
6596 If there is a CASE_LABEL for VAL, its index is placed in IDX and true is
6599 If there is no CASE_LABEL for VAL and there is one that is larger than VAL,
6600 it is placed in IDX and false is returned.
6602 If VAL is larger than any CASE_LABEL, n is placed on IDX and false is
6606 find_case_label_index (gimple stmt
, size_t start_idx
, tree val
, size_t *idx
)
6608 size_t n
= gimple_switch_num_labels (stmt
);
6611 /* Find case label for minimum of the value range or the next one.
6612 At each iteration we are searching in [low, high - 1]. */
6614 for (low
= start_idx
, high
= n
; high
!= low
; )
6618 /* Note that i != high, so we never ask for n. */
6619 size_t i
= (high
+ low
) / 2;
6620 t
= gimple_switch_label (stmt
, i
);
6622 /* Cache the result of comparing CASE_LOW and val. */
6623 cmp
= tree_int_cst_compare (CASE_LOW (t
), val
);
6627 /* Ranges cannot be empty. */
6636 if (CASE_HIGH (t
) != NULL
6637 && tree_int_cst_compare (CASE_HIGH (t
), val
) >= 0)
6649 /* Searches the case label vector VEC for the range of CASE_LABELs that is used
6650 for values between MIN and MAX. The first index is placed in MIN_IDX. The
6651 last index is placed in MAX_IDX. If the range of CASE_LABELs is empty
6652 then MAX_IDX < MIN_IDX.
6653 Returns true if the default label is not needed. */
6656 find_case_label_range (gimple stmt
, tree min
, tree max
, size_t *min_idx
,
6660 bool min_take_default
= !find_case_label_index (stmt
, 1, min
, &i
);
6661 bool max_take_default
= !find_case_label_index (stmt
, i
, max
, &j
);
6665 && max_take_default
)
6667 /* Only the default case label reached.
6668 Return an empty range. */
6675 bool take_default
= min_take_default
|| max_take_default
;
6679 if (max_take_default
)
6682 /* If the case label range is continuous, we do not need
6683 the default case label. Verify that. */
6684 high
= CASE_LOW (gimple_switch_label (stmt
, i
));
6685 if (CASE_HIGH (gimple_switch_label (stmt
, i
)))
6686 high
= CASE_HIGH (gimple_switch_label (stmt
, i
));
6687 for (k
= i
+ 1; k
<= j
; ++k
)
6689 low
= CASE_LOW (gimple_switch_label (stmt
, k
));
6690 if (!integer_onep (int_const_binop (MINUS_EXPR
, low
, high
)))
6692 take_default
= true;
6696 if (CASE_HIGH (gimple_switch_label (stmt
, k
)))
6697 high
= CASE_HIGH (gimple_switch_label (stmt
, k
));
6702 return !take_default
;
6706 /* Visit switch statement STMT. If we can determine which edge
6707 will be taken out of STMT's basic block, record it in
6708 *TAKEN_EDGE_P and return SSA_PROP_INTERESTING. Otherwise, return
6709 SSA_PROP_VARYING. */
6711 static enum ssa_prop_result
6712 vrp_visit_switch_stmt (gimple stmt
, edge
*taken_edge_p
)
6716 size_t i
= 0, j
= 0;
6719 *taken_edge_p
= NULL
;
6720 op
= gimple_switch_index (stmt
);
6721 if (TREE_CODE (op
) != SSA_NAME
)
6722 return SSA_PROP_VARYING
;
6724 vr
= get_value_range (op
);
6725 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
6727 fprintf (dump_file
, "\nVisiting switch expression with operand ");
6728 print_generic_expr (dump_file
, op
, 0);
6729 fprintf (dump_file
, " with known range ");
6730 dump_value_range (dump_file
, vr
);
6731 fprintf (dump_file
, "\n");
6734 if (vr
->type
!= VR_RANGE
6735 || symbolic_range_p (vr
))
6736 return SSA_PROP_VARYING
;
6738 /* Find the single edge that is taken from the switch expression. */
6739 take_default
= !find_case_label_range (stmt
, vr
->min
, vr
->max
, &i
, &j
);
6741 /* Check if the range spans no CASE_LABEL. If so, we only reach the default
6745 gcc_assert (take_default
);
6746 val
= gimple_switch_default_label (stmt
);
6750 /* Check if labels with index i to j and maybe the default label
6751 are all reaching the same label. */
6753 val
= gimple_switch_label (stmt
, i
);
6755 && CASE_LABEL (gimple_switch_default_label (stmt
))
6756 != CASE_LABEL (val
))
6758 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
6759 fprintf (dump_file
, " not a single destination for this "
6761 return SSA_PROP_VARYING
;
6763 for (++i
; i
<= j
; ++i
)
6765 if (CASE_LABEL (gimple_switch_label (stmt
, i
)) != CASE_LABEL (val
))
6767 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
6768 fprintf (dump_file
, " not a single destination for this "
6770 return SSA_PROP_VARYING
;
6775 *taken_edge_p
= find_edge (gimple_bb (stmt
),
6776 label_to_block (CASE_LABEL (val
)));
6778 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
6780 fprintf (dump_file
, " will take edge to ");
6781 print_generic_stmt (dump_file
, CASE_LABEL (val
), 0);
6784 return SSA_PROP_INTERESTING
;
6788 /* Evaluate statement STMT. If the statement produces a useful range,
6789 return SSA_PROP_INTERESTING and record the SSA name with the
6790 interesting range into *OUTPUT_P.
6792 If STMT is a conditional branch and we can determine its truth
6793 value, the taken edge is recorded in *TAKEN_EDGE_P.
6795 If STMT produces a varying value, return SSA_PROP_VARYING. */
6797 static enum ssa_prop_result
6798 vrp_visit_stmt (gimple stmt
, edge
*taken_edge_p
, tree
*output_p
)
6803 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
6805 fprintf (dump_file
, "\nVisiting statement:\n");
6806 print_gimple_stmt (dump_file
, stmt
, 0, dump_flags
);
6807 fprintf (dump_file
, "\n");
6810 if (!stmt_interesting_for_vrp (stmt
))
6811 gcc_assert (stmt_ends_bb_p (stmt
));
6812 else if (is_gimple_assign (stmt
) || is_gimple_call (stmt
))
6814 /* In general, assignments with virtual operands are not useful
6815 for deriving ranges, with the obvious exception of calls to
6816 builtin functions. */
6817 if ((is_gimple_call (stmt
)
6818 && gimple_call_fndecl (stmt
) != NULL_TREE
6819 && DECL_BUILT_IN (gimple_call_fndecl (stmt
)))
6820 || !gimple_vuse (stmt
))
6821 return vrp_visit_assignment_or_call (stmt
, output_p
);
6823 else if (gimple_code (stmt
) == GIMPLE_COND
)
6824 return vrp_visit_cond_stmt (stmt
, taken_edge_p
);
6825 else if (gimple_code (stmt
) == GIMPLE_SWITCH
)
6826 return vrp_visit_switch_stmt (stmt
, taken_edge_p
);
6828 /* All other statements produce nothing of interest for VRP, so mark
6829 their outputs varying and prevent further simulation. */
6830 FOR_EACH_SSA_TREE_OPERAND (def
, stmt
, iter
, SSA_OP_DEF
)
6831 set_value_range_to_varying (get_value_range (def
));
6833 return SSA_PROP_VARYING
;
6837 /* Meet operation for value ranges. Given two value ranges VR0 and
6838 VR1, store in VR0 a range that contains both VR0 and VR1. This
6839 may not be the smallest possible such range. */
6842 vrp_meet (value_range_t
*vr0
, value_range_t
*vr1
)
6844 if (vr0
->type
== VR_UNDEFINED
)
6846 copy_value_range (vr0
, vr1
);
6850 if (vr1
->type
== VR_UNDEFINED
)
6852 /* Nothing to do. VR0 already has the resulting range. */
6856 if (vr0
->type
== VR_VARYING
)
6858 /* Nothing to do. VR0 already has the resulting range. */
6862 if (vr1
->type
== VR_VARYING
)
6864 set_value_range_to_varying (vr0
);
6868 if (vr0
->type
== VR_RANGE
&& vr1
->type
== VR_RANGE
)
6873 /* Compute the convex hull of the ranges. The lower limit of
6874 the new range is the minimum of the two ranges. If they
6875 cannot be compared, then give up. */
6876 cmp
= compare_values (vr0
->min
, vr1
->min
);
6877 if (cmp
== 0 || cmp
== 1)
6884 /* Similarly, the upper limit of the new range is the maximum
6885 of the two ranges. If they cannot be compared, then
6887 cmp
= compare_values (vr0
->max
, vr1
->max
);
6888 if (cmp
== 0 || cmp
== -1)
6895 /* Check for useless ranges. */
6896 if (INTEGRAL_TYPE_P (TREE_TYPE (min
))
6897 && ((vrp_val_is_min (min
) || is_overflow_infinity (min
))
6898 && (vrp_val_is_max (max
) || is_overflow_infinity (max
))))
6901 /* The resulting set of equivalences is the intersection of
6903 if (vr0
->equiv
&& vr1
->equiv
&& vr0
->equiv
!= vr1
->equiv
)
6904 bitmap_and_into (vr0
->equiv
, vr1
->equiv
);
6905 else if (vr0
->equiv
&& !vr1
->equiv
)
6906 bitmap_clear (vr0
->equiv
);
6908 set_value_range (vr0
, vr0
->type
, min
, max
, vr0
->equiv
);
6910 else if (vr0
->type
== VR_ANTI_RANGE
&& vr1
->type
== VR_ANTI_RANGE
)
6912 /* Two anti-ranges meet only if their complements intersect.
6913 Only handle the case of identical ranges. */
6914 if (compare_values (vr0
->min
, vr1
->min
) == 0
6915 && compare_values (vr0
->max
, vr1
->max
) == 0
6916 && compare_values (vr0
->min
, vr0
->max
) == 0)
6918 /* The resulting set of equivalences is the intersection of
6920 if (vr0
->equiv
&& vr1
->equiv
&& vr0
->equiv
!= vr1
->equiv
)
6921 bitmap_and_into (vr0
->equiv
, vr1
->equiv
);
6922 else if (vr0
->equiv
&& !vr1
->equiv
)
6923 bitmap_clear (vr0
->equiv
);
6928 else if (vr0
->type
== VR_ANTI_RANGE
|| vr1
->type
== VR_ANTI_RANGE
)
6930 /* For a numeric range [VAL1, VAL2] and an anti-range ~[VAL3, VAL4],
6931 only handle the case where the ranges have an empty intersection.
6932 The result of the meet operation is the anti-range. */
6933 if (!symbolic_range_p (vr0
)
6934 && !symbolic_range_p (vr1
)
6935 && !value_ranges_intersect_p (vr0
, vr1
))
6937 /* Copy most of VR1 into VR0. Don't copy VR1's equivalence
6938 set. We need to compute the intersection of the two
6939 equivalence sets. */
6940 if (vr1
->type
== VR_ANTI_RANGE
)
6941 set_value_range (vr0
, vr1
->type
, vr1
->min
, vr1
->max
, vr0
->equiv
);
6943 /* The resulting set of equivalences is the intersection of
6945 if (vr0
->equiv
&& vr1
->equiv
&& vr0
->equiv
!= vr1
->equiv
)
6946 bitmap_and_into (vr0
->equiv
, vr1
->equiv
);
6947 else if (vr0
->equiv
&& !vr1
->equiv
)
6948 bitmap_clear (vr0
->equiv
);
6959 /* Failed to find an efficient meet. Before giving up and setting
6960 the result to VARYING, see if we can at least derive a useful
6961 anti-range. FIXME, all this nonsense about distinguishing
6962 anti-ranges from ranges is necessary because of the odd
6963 semantics of range_includes_zero_p and friends. */
6964 if (!symbolic_range_p (vr0
)
6965 && ((vr0
->type
== VR_RANGE
&& !range_includes_zero_p (vr0
))
6966 || (vr0
->type
== VR_ANTI_RANGE
&& range_includes_zero_p (vr0
)))
6967 && !symbolic_range_p (vr1
)
6968 && ((vr1
->type
== VR_RANGE
&& !range_includes_zero_p (vr1
))
6969 || (vr1
->type
== VR_ANTI_RANGE
&& range_includes_zero_p (vr1
))))
6971 set_value_range_to_nonnull (vr0
, TREE_TYPE (vr0
->min
));
6973 /* Since this meet operation did not result from the meeting of
6974 two equivalent names, VR0 cannot have any equivalences. */
6976 bitmap_clear (vr0
->equiv
);
6979 set_value_range_to_varying (vr0
);
6983 /* Visit all arguments for PHI node PHI that flow through executable
6984 edges. If a valid value range can be derived from all the incoming
6985 value ranges, set a new range for the LHS of PHI. */
6987 static enum ssa_prop_result
6988 vrp_visit_phi_node (gimple phi
)
6991 tree lhs
= PHI_RESULT (phi
);
6992 value_range_t
*lhs_vr
= get_value_range (lhs
);
6993 value_range_t vr_result
= { VR_UNDEFINED
, NULL_TREE
, NULL_TREE
, NULL
};
6994 int edges
, old_edges
;
6997 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
6999 fprintf (dump_file
, "\nVisiting PHI node: ");
7000 print_gimple_stmt (dump_file
, phi
, 0, dump_flags
);
7004 for (i
= 0; i
< gimple_phi_num_args (phi
); i
++)
7006 edge e
= gimple_phi_arg_edge (phi
, i
);
7008 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
7011 "\n Argument #%d (%d -> %d %sexecutable)\n",
7012 (int) i
, e
->src
->index
, e
->dest
->index
,
7013 (e
->flags
& EDGE_EXECUTABLE
) ? "" : "not ");
7016 if (e
->flags
& EDGE_EXECUTABLE
)
7018 tree arg
= PHI_ARG_DEF (phi
, i
);
7019 value_range_t vr_arg
;
7023 if (TREE_CODE (arg
) == SSA_NAME
)
7025 vr_arg
= *(get_value_range (arg
));
7029 if (is_overflow_infinity (arg
))
7031 arg
= copy_node (arg
);
7032 TREE_OVERFLOW (arg
) = 0;
7035 vr_arg
.type
= VR_RANGE
;
7038 vr_arg
.equiv
= NULL
;
7041 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
7043 fprintf (dump_file
, "\t");
7044 print_generic_expr (dump_file
, arg
, dump_flags
);
7045 fprintf (dump_file
, "\n\tValue: ");
7046 dump_value_range (dump_file
, &vr_arg
);
7047 fprintf (dump_file
, "\n");
7050 vrp_meet (&vr_result
, &vr_arg
);
7052 if (vr_result
.type
== VR_VARYING
)
7057 if (vr_result
.type
== VR_VARYING
)
7059 else if (vr_result
.type
== VR_UNDEFINED
)
7062 old_edges
= vr_phi_edge_counts
[SSA_NAME_VERSION (lhs
)];
7063 vr_phi_edge_counts
[SSA_NAME_VERSION (lhs
)] = edges
;
7065 /* To prevent infinite iterations in the algorithm, derive ranges
7066 when the new value is slightly bigger or smaller than the
7067 previous one. We don't do this if we have seen a new executable
7068 edge; this helps us avoid an overflow infinity for conditionals
7069 which are not in a loop. */
7071 && gimple_phi_num_args (phi
) > 1
7072 && edges
== old_edges
)
7074 int cmp_min
= compare_values (lhs_vr
->min
, vr_result
.min
);
7075 int cmp_max
= compare_values (lhs_vr
->max
, vr_result
.max
);
7077 /* For non VR_RANGE or for pointers fall back to varying if
7078 the range changed. */
7079 if ((lhs_vr
->type
!= VR_RANGE
|| vr_result
.type
!= VR_RANGE
7080 || POINTER_TYPE_P (TREE_TYPE (lhs
)))
7081 && (cmp_min
!= 0 || cmp_max
!= 0))
7084 /* If the new minimum is smaller or larger than the previous
7085 one, go all the way to -INF. In the first case, to avoid
7086 iterating millions of times to reach -INF, and in the
7087 other case to avoid infinite bouncing between different
7089 if (cmp_min
> 0 || cmp_min
< 0)
7091 if (!needs_overflow_infinity (TREE_TYPE (vr_result
.min
))
7092 || !vrp_var_may_overflow (lhs
, phi
))
7093 vr_result
.min
= TYPE_MIN_VALUE (TREE_TYPE (vr_result
.min
));
7094 else if (supports_overflow_infinity (TREE_TYPE (vr_result
.min
)))
7096 negative_overflow_infinity (TREE_TYPE (vr_result
.min
));
7099 /* Similarly, if the new maximum is smaller or larger than
7100 the previous one, go all the way to +INF. */
7101 if (cmp_max
< 0 || cmp_max
> 0)
7103 if (!needs_overflow_infinity (TREE_TYPE (vr_result
.max
))
7104 || !vrp_var_may_overflow (lhs
, phi
))
7105 vr_result
.max
= TYPE_MAX_VALUE (TREE_TYPE (vr_result
.max
));
7106 else if (supports_overflow_infinity (TREE_TYPE (vr_result
.max
)))
7108 positive_overflow_infinity (TREE_TYPE (vr_result
.max
));
7111 /* If we dropped either bound to +-INF then if this is a loop
7112 PHI node SCEV may known more about its value-range. */
7113 if ((cmp_min
> 0 || cmp_min
< 0
7114 || cmp_max
< 0 || cmp_max
> 0)
7116 && (l
= loop_containing_stmt (phi
))
7117 && l
->header
== gimple_bb (phi
))
7118 adjust_range_with_scev (&vr_result
, l
, phi
, lhs
);
7120 /* If we will end up with a (-INF, +INF) range, set it to
7121 VARYING. Same if the previous max value was invalid for
7122 the type and we end up with vr_result.min > vr_result.max. */
7123 if ((vrp_val_is_max (vr_result
.max
)
7124 && vrp_val_is_min (vr_result
.min
))
7125 || compare_values (vr_result
.min
,
7130 /* If the new range is different than the previous value, keep
7133 if (update_value_range (lhs
, &vr_result
))
7135 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
7137 fprintf (dump_file
, "Found new range for ");
7138 print_generic_expr (dump_file
, lhs
, 0);
7139 fprintf (dump_file
, ": ");
7140 dump_value_range (dump_file
, &vr_result
);
7141 fprintf (dump_file
, "\n\n");
7144 return SSA_PROP_INTERESTING
;
7147 /* Nothing changed, don't add outgoing edges. */
7148 return SSA_PROP_NOT_INTERESTING
;
7150 /* No match found. Set the LHS to VARYING. */
7152 set_value_range_to_varying (lhs_vr
);
7153 return SSA_PROP_VARYING
;
7156 /* Simplify boolean operations if the source is known
7157 to be already a boolean. */
7159 simplify_truth_ops_using_ranges (gimple_stmt_iterator
*gsi
, gimple stmt
)
7161 enum tree_code rhs_code
= gimple_assign_rhs_code (stmt
);
7163 bool need_conversion
;
7165 /* We handle only !=/== case here. */
7166 gcc_assert (rhs_code
== EQ_EXPR
|| rhs_code
== NE_EXPR
);
7168 op0
= gimple_assign_rhs1 (stmt
);
7169 if (!op_with_boolean_value_range_p (op0
))
7172 op1
= gimple_assign_rhs2 (stmt
);
7173 if (!op_with_boolean_value_range_p (op1
))
7176 /* Reduce number of cases to handle to NE_EXPR. As there is no
7177 BIT_XNOR_EXPR we cannot replace A == B with a single statement. */
7178 if (rhs_code
== EQ_EXPR
)
7180 if (TREE_CODE (op1
) == INTEGER_CST
)
7181 op1
= int_const_binop (BIT_XOR_EXPR
, op1
, integer_one_node
);
7186 lhs
= gimple_assign_lhs (stmt
);
7188 = !useless_type_conversion_p (TREE_TYPE (lhs
), TREE_TYPE (op0
));
7190 /* Make sure to not sign-extend a 1-bit 1 when converting the result. */
7192 && !TYPE_UNSIGNED (TREE_TYPE (op0
))
7193 && TYPE_PRECISION (TREE_TYPE (op0
)) == 1
7194 && TYPE_PRECISION (TREE_TYPE (lhs
)) > 1)
7197 /* For A != 0 we can substitute A itself. */
7198 if (integer_zerop (op1
))
7199 gimple_assign_set_rhs_with_ops (gsi
,
7201 ? NOP_EXPR
: TREE_CODE (op0
),
7203 /* For A != B we substitute A ^ B. Either with conversion. */
7204 else if (need_conversion
)
7207 tree tem
= create_tmp_reg (TREE_TYPE (op0
), NULL
);
7208 newop
= gimple_build_assign_with_ops (BIT_XOR_EXPR
, tem
, op0
, op1
);
7209 tem
= make_ssa_name (tem
, newop
);
7210 gimple_assign_set_lhs (newop
, tem
);
7211 gsi_insert_before (gsi
, newop
, GSI_SAME_STMT
);
7212 update_stmt (newop
);
7213 gimple_assign_set_rhs_with_ops (gsi
, NOP_EXPR
, tem
, NULL_TREE
);
7217 gimple_assign_set_rhs_with_ops (gsi
, BIT_XOR_EXPR
, op0
, op1
);
7218 update_stmt (gsi_stmt (*gsi
));
7223 /* Simplify a division or modulo operator to a right shift or
7224 bitwise and if the first operand is unsigned or is greater
7225 than zero and the second operand is an exact power of two. */
7228 simplify_div_or_mod_using_ranges (gimple stmt
)
7230 enum tree_code rhs_code
= gimple_assign_rhs_code (stmt
);
7232 tree op0
= gimple_assign_rhs1 (stmt
);
7233 tree op1
= gimple_assign_rhs2 (stmt
);
7234 value_range_t
*vr
= get_value_range (gimple_assign_rhs1 (stmt
));
7236 if (TYPE_UNSIGNED (TREE_TYPE (op0
)))
7238 val
= integer_one_node
;
7244 val
= compare_range_with_value (GE_EXPR
, vr
, integer_zero_node
, &sop
);
7248 && integer_onep (val
)
7249 && issue_strict_overflow_warning (WARN_STRICT_OVERFLOW_MISC
))
7251 location_t location
;
7253 if (!gimple_has_location (stmt
))
7254 location
= input_location
;
7256 location
= gimple_location (stmt
);
7257 warning_at (location
, OPT_Wstrict_overflow
,
7258 "assuming signed overflow does not occur when "
7259 "simplifying %</%> or %<%%%> to %<>>%> or %<&%>");
7263 if (val
&& integer_onep (val
))
7267 if (rhs_code
== TRUNC_DIV_EXPR
)
7269 t
= build_int_cst (integer_type_node
, tree_log2 (op1
));
7270 gimple_assign_set_rhs_code (stmt
, RSHIFT_EXPR
);
7271 gimple_assign_set_rhs1 (stmt
, op0
);
7272 gimple_assign_set_rhs2 (stmt
, t
);
7276 t
= build_int_cst (TREE_TYPE (op1
), 1);
7277 t
= int_const_binop (MINUS_EXPR
, op1
, t
);
7278 t
= fold_convert (TREE_TYPE (op0
), t
);
7280 gimple_assign_set_rhs_code (stmt
, BIT_AND_EXPR
);
7281 gimple_assign_set_rhs1 (stmt
, op0
);
7282 gimple_assign_set_rhs2 (stmt
, t
);
7292 /* If the operand to an ABS_EXPR is >= 0, then eliminate the
7293 ABS_EXPR. If the operand is <= 0, then simplify the
7294 ABS_EXPR into a NEGATE_EXPR. */
7297 simplify_abs_using_ranges (gimple stmt
)
7300 tree op
= gimple_assign_rhs1 (stmt
);
7301 tree type
= TREE_TYPE (op
);
7302 value_range_t
*vr
= get_value_range (op
);
7304 if (TYPE_UNSIGNED (type
))
7306 val
= integer_zero_node
;
7312 val
= compare_range_with_value (LE_EXPR
, vr
, integer_zero_node
, &sop
);
7316 val
= compare_range_with_value (GE_EXPR
, vr
, integer_zero_node
,
7321 if (integer_zerop (val
))
7322 val
= integer_one_node
;
7323 else if (integer_onep (val
))
7324 val
= integer_zero_node
;
7329 && (integer_onep (val
) || integer_zerop (val
)))
7331 if (sop
&& issue_strict_overflow_warning (WARN_STRICT_OVERFLOW_MISC
))
7333 location_t location
;
7335 if (!gimple_has_location (stmt
))
7336 location
= input_location
;
7338 location
= gimple_location (stmt
);
7339 warning_at (location
, OPT_Wstrict_overflow
,
7340 "assuming signed overflow does not occur when "
7341 "simplifying %<abs (X)%> to %<X%> or %<-X%>");
7344 gimple_assign_set_rhs1 (stmt
, op
);
7345 if (integer_onep (val
))
7346 gimple_assign_set_rhs_code (stmt
, NEGATE_EXPR
);
7348 gimple_assign_set_rhs_code (stmt
, SSA_NAME
);
7357 /* Optimize away redundant BIT_AND_EXPR and BIT_IOR_EXPR.
7358 If all the bits that are being cleared by & are already
7359 known to be zero from VR, or all the bits that are being
7360 set by | are already known to be one from VR, the bit
7361 operation is redundant. */
7364 simplify_bit_ops_using_ranges (gimple_stmt_iterator
*gsi
, gimple stmt
)
7366 tree op0
= gimple_assign_rhs1 (stmt
);
7367 tree op1
= gimple_assign_rhs2 (stmt
);
7368 tree op
= NULL_TREE
;
7369 value_range_t vr0
= { VR_UNDEFINED
, NULL_TREE
, NULL_TREE
, NULL
};
7370 value_range_t vr1
= { VR_UNDEFINED
, NULL_TREE
, NULL_TREE
, NULL
};
7371 double_int may_be_nonzero0
, may_be_nonzero1
;
7372 double_int must_be_nonzero0
, must_be_nonzero1
;
7375 if (TREE_CODE (op0
) == SSA_NAME
)
7376 vr0
= *(get_value_range (op0
));
7377 else if (is_gimple_min_invariant (op0
))
7378 set_value_range_to_value (&vr0
, op0
, NULL
);
7382 if (TREE_CODE (op1
) == SSA_NAME
)
7383 vr1
= *(get_value_range (op1
));
7384 else if (is_gimple_min_invariant (op1
))
7385 set_value_range_to_value (&vr1
, op1
, NULL
);
7389 if (!zero_nonzero_bits_from_vr (&vr0
, &may_be_nonzero0
, &must_be_nonzero0
))
7391 if (!zero_nonzero_bits_from_vr (&vr1
, &may_be_nonzero1
, &must_be_nonzero1
))
7394 switch (gimple_assign_rhs_code (stmt
))
7397 mask
= double_int_and_not (may_be_nonzero0
, must_be_nonzero1
);
7398 if (double_int_zero_p (mask
))
7403 mask
= double_int_and_not (may_be_nonzero1
, must_be_nonzero0
);
7404 if (double_int_zero_p (mask
))
7411 mask
= double_int_and_not (may_be_nonzero0
, must_be_nonzero1
);
7412 if (double_int_zero_p (mask
))
7417 mask
= double_int_and_not (may_be_nonzero1
, must_be_nonzero0
);
7418 if (double_int_zero_p (mask
))
7428 if (op
== NULL_TREE
)
7431 gimple_assign_set_rhs_with_ops (gsi
, TREE_CODE (op
), op
, NULL
);
7432 update_stmt (gsi_stmt (*gsi
));
7436 /* We are comparing trees OP0 and OP1 using COND_CODE. OP0 has
7437 a known value range VR.
7439 If there is one and only one value which will satisfy the
7440 conditional, then return that value. Else return NULL. */
7443 test_for_singularity (enum tree_code cond_code
, tree op0
,
7444 tree op1
, value_range_t
*vr
)
7449 /* Extract minimum/maximum values which satisfy the
7450 the conditional as it was written. */
7451 if (cond_code
== LE_EXPR
|| cond_code
== LT_EXPR
)
7453 /* This should not be negative infinity; there is no overflow
7455 min
= TYPE_MIN_VALUE (TREE_TYPE (op0
));
7458 if (cond_code
== LT_EXPR
&& !is_overflow_infinity (max
))
7460 tree one
= build_int_cst (TREE_TYPE (op0
), 1);
7461 max
= fold_build2 (MINUS_EXPR
, TREE_TYPE (op0
), max
, one
);
7463 TREE_NO_WARNING (max
) = 1;
7466 else if (cond_code
== GE_EXPR
|| cond_code
== GT_EXPR
)
7468 /* This should not be positive infinity; there is no overflow
7470 max
= TYPE_MAX_VALUE (TREE_TYPE (op0
));
7473 if (cond_code
== GT_EXPR
&& !is_overflow_infinity (min
))
7475 tree one
= build_int_cst (TREE_TYPE (op0
), 1);
7476 min
= fold_build2 (PLUS_EXPR
, TREE_TYPE (op0
), min
, one
);
7478 TREE_NO_WARNING (min
) = 1;
7482 /* Now refine the minimum and maximum values using any
7483 value range information we have for op0. */
7486 if (compare_values (vr
->min
, min
) == 1)
7488 if (compare_values (vr
->max
, max
) == -1)
7491 /* If the new min/max values have converged to a single value,
7492 then there is only one value which can satisfy the condition,
7493 return that value. */
7494 if (operand_equal_p (min
, max
, 0) && is_gimple_min_invariant (min
))
7500 /* Simplify a conditional using a relational operator to an equality
7501 test if the range information indicates only one value can satisfy
7502 the original conditional. */
7505 simplify_cond_using_ranges (gimple stmt
)
7507 tree op0
= gimple_cond_lhs (stmt
);
7508 tree op1
= gimple_cond_rhs (stmt
);
7509 enum tree_code cond_code
= gimple_cond_code (stmt
);
7511 if (cond_code
!= NE_EXPR
7512 && cond_code
!= EQ_EXPR
7513 && TREE_CODE (op0
) == SSA_NAME
7514 && INTEGRAL_TYPE_P (TREE_TYPE (op0
))
7515 && is_gimple_min_invariant (op1
))
7517 value_range_t
*vr
= get_value_range (op0
);
7519 /* If we have range information for OP0, then we might be
7520 able to simplify this conditional. */
7521 if (vr
->type
== VR_RANGE
)
7523 tree new_tree
= test_for_singularity (cond_code
, op0
, op1
, vr
);
7529 fprintf (dump_file
, "Simplified relational ");
7530 print_gimple_stmt (dump_file
, stmt
, 0, 0);
7531 fprintf (dump_file
, " into ");
7534 gimple_cond_set_code (stmt
, EQ_EXPR
);
7535 gimple_cond_set_lhs (stmt
, op0
);
7536 gimple_cond_set_rhs (stmt
, new_tree
);
7542 print_gimple_stmt (dump_file
, stmt
, 0, 0);
7543 fprintf (dump_file
, "\n");
7549 /* Try again after inverting the condition. We only deal
7550 with integral types here, so no need to worry about
7551 issues with inverting FP comparisons. */
7552 cond_code
= invert_tree_comparison (cond_code
, false);
7553 new_tree
= test_for_singularity (cond_code
, op0
, op1
, vr
);
7559 fprintf (dump_file
, "Simplified relational ");
7560 print_gimple_stmt (dump_file
, stmt
, 0, 0);
7561 fprintf (dump_file
, " into ");
7564 gimple_cond_set_code (stmt
, NE_EXPR
);
7565 gimple_cond_set_lhs (stmt
, op0
);
7566 gimple_cond_set_rhs (stmt
, new_tree
);
7572 print_gimple_stmt (dump_file
, stmt
, 0, 0);
7573 fprintf (dump_file
, "\n");
7584 /* Simplify a switch statement using the value range of the switch
7588 simplify_switch_using_ranges (gimple stmt
)
7590 tree op
= gimple_switch_index (stmt
);
7595 size_t i
= 0, j
= 0, n
, n2
;
7599 if (TREE_CODE (op
) == SSA_NAME
)
7601 vr
= get_value_range (op
);
7603 /* We can only handle integer ranges. */
7604 if (vr
->type
!= VR_RANGE
7605 || symbolic_range_p (vr
))
7608 /* Find case label for min/max of the value range. */
7609 take_default
= !find_case_label_range (stmt
, vr
->min
, vr
->max
, &i
, &j
);
7611 else if (TREE_CODE (op
) == INTEGER_CST
)
7613 take_default
= !find_case_label_index (stmt
, 1, op
, &i
);
7627 n
= gimple_switch_num_labels (stmt
);
7629 /* Bail out if this is just all edges taken. */
7635 /* Build a new vector of taken case labels. */
7636 vec2
= make_tree_vec (j
- i
+ 1 + (int)take_default
);
7639 /* Add the default edge, if necessary. */
7641 TREE_VEC_ELT (vec2
, n2
++) = gimple_switch_default_label (stmt
);
7643 for (; i
<= j
; ++i
, ++n2
)
7644 TREE_VEC_ELT (vec2
, n2
) = gimple_switch_label (stmt
, i
);
7646 /* Mark needed edges. */
7647 for (i
= 0; i
< n2
; ++i
)
7649 e
= find_edge (gimple_bb (stmt
),
7650 label_to_block (CASE_LABEL (TREE_VEC_ELT (vec2
, i
))));
7651 e
->aux
= (void *)-1;
7654 /* Queue not needed edges for later removal. */
7655 FOR_EACH_EDGE (e
, ei
, gimple_bb (stmt
)->succs
)
7657 if (e
->aux
== (void *)-1)
7663 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
7665 fprintf (dump_file
, "removing unreachable case label\n");
7667 VEC_safe_push (edge
, heap
, to_remove_edges
, e
);
7668 e
->flags
&= ~EDGE_EXECUTABLE
;
7671 /* And queue an update for the stmt. */
7674 VEC_safe_push (switch_update
, heap
, to_update_switch_stmts
, &su
);
7678 /* Simplify an integral conversion from an SSA name in STMT. */
7681 simplify_conversion_using_ranges (gimple stmt
)
7683 tree innerop
, middleop
, finaltype
;
7685 value_range_t
*innervr
;
7686 bool inner_unsigned_p
, middle_unsigned_p
, final_unsigned_p
;
7687 unsigned inner_prec
, middle_prec
, final_prec
;
7688 double_int innermin
, innermed
, innermax
, middlemin
, middlemed
, middlemax
;
7690 finaltype
= TREE_TYPE (gimple_assign_lhs (stmt
));
7691 if (!INTEGRAL_TYPE_P (finaltype
))
7693 middleop
= gimple_assign_rhs1 (stmt
);
7694 def_stmt
= SSA_NAME_DEF_STMT (middleop
);
7695 if (!is_gimple_assign (def_stmt
)
7696 || !CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (def_stmt
)))
7698 innerop
= gimple_assign_rhs1 (def_stmt
);
7699 if (TREE_CODE (innerop
) != SSA_NAME
)
7702 /* Get the value-range of the inner operand. */
7703 innervr
= get_value_range (innerop
);
7704 if (innervr
->type
!= VR_RANGE
7705 || TREE_CODE (innervr
->min
) != INTEGER_CST
7706 || TREE_CODE (innervr
->max
) != INTEGER_CST
)
7709 /* Simulate the conversion chain to check if the result is equal if
7710 the middle conversion is removed. */
7711 innermin
= tree_to_double_int (innervr
->min
);
7712 innermax
= tree_to_double_int (innervr
->max
);
7714 inner_prec
= TYPE_PRECISION (TREE_TYPE (innerop
));
7715 middle_prec
= TYPE_PRECISION (TREE_TYPE (middleop
));
7716 final_prec
= TYPE_PRECISION (finaltype
);
7718 /* If the first conversion is not injective, the second must not
7720 if (double_int_cmp (double_int_sub (innermax
, innermin
),
7721 double_int_mask (middle_prec
), true) > 0
7722 && middle_prec
< final_prec
)
7724 /* We also want a medium value so that we can track the effect that
7725 narrowing conversions with sign change have. */
7726 inner_unsigned_p
= TYPE_UNSIGNED (TREE_TYPE (innerop
));
7727 if (inner_unsigned_p
)
7728 innermed
= double_int_rshift (double_int_mask (inner_prec
),
7729 1, inner_prec
, false);
7731 innermed
= double_int_zero
;
7732 if (double_int_cmp (innermin
, innermed
, inner_unsigned_p
) >= 0
7733 || double_int_cmp (innermed
, innermax
, inner_unsigned_p
) >= 0)
7734 innermed
= innermin
;
7736 middle_unsigned_p
= TYPE_UNSIGNED (TREE_TYPE (middleop
));
7737 middlemin
= double_int_ext (innermin
, middle_prec
, middle_unsigned_p
);
7738 middlemed
= double_int_ext (innermed
, middle_prec
, middle_unsigned_p
);
7739 middlemax
= double_int_ext (innermax
, middle_prec
, middle_unsigned_p
);
7741 /* Require that the final conversion applied to both the original
7742 and the intermediate range produces the same result. */
7743 final_unsigned_p
= TYPE_UNSIGNED (finaltype
);
7744 if (!double_int_equal_p (double_int_ext (middlemin
,
7745 final_prec
, final_unsigned_p
),
7746 double_int_ext (innermin
,
7747 final_prec
, final_unsigned_p
))
7748 || !double_int_equal_p (double_int_ext (middlemed
,
7749 final_prec
, final_unsigned_p
),
7750 double_int_ext (innermed
,
7751 final_prec
, final_unsigned_p
))
7752 || !double_int_equal_p (double_int_ext (middlemax
,
7753 final_prec
, final_unsigned_p
),
7754 double_int_ext (innermax
,
7755 final_prec
, final_unsigned_p
)))
7758 gimple_assign_set_rhs1 (stmt
, innerop
);
7763 /* Return whether the value range *VR fits in an integer type specified
7764 by PRECISION and UNSIGNED_P. */
7767 range_fits_type_p (value_range_t
*vr
, unsigned precision
, bool unsigned_p
)
7770 unsigned src_precision
;
7773 /* We can only handle integral and pointer types. */
7774 src_type
= TREE_TYPE (vr
->min
);
7775 if (!INTEGRAL_TYPE_P (src_type
)
7776 && !POINTER_TYPE_P (src_type
))
7779 /* An extension is always fine, so is an identity transform. */
7780 src_precision
= TYPE_PRECISION (TREE_TYPE (vr
->min
));
7781 if (src_precision
< precision
7782 || (src_precision
== precision
7783 && TYPE_UNSIGNED (src_type
) == unsigned_p
))
7786 /* Now we can only handle ranges with constant bounds. */
7787 if (vr
->type
!= VR_RANGE
7788 || TREE_CODE (vr
->min
) != INTEGER_CST
7789 || TREE_CODE (vr
->max
) != INTEGER_CST
)
7792 /* For precision-preserving sign-changes the MSB of the double-int
7794 if (src_precision
== precision
7795 && (TREE_INT_CST_HIGH (vr
->min
) | TREE_INT_CST_HIGH (vr
->max
)) < 0)
7798 /* Then we can perform the conversion on both ends and compare
7799 the result for equality. */
7800 tem
= double_int_ext (tree_to_double_int (vr
->min
), precision
, unsigned_p
);
7801 if (!double_int_equal_p (tree_to_double_int (vr
->min
), tem
))
7803 tem
= double_int_ext (tree_to_double_int (vr
->max
), precision
, unsigned_p
);
7804 if (!double_int_equal_p (tree_to_double_int (vr
->max
), tem
))
7810 /* Simplify a conversion from integral SSA name to float in STMT. */
7813 simplify_float_conversion_using_ranges (gimple_stmt_iterator
*gsi
, gimple stmt
)
7815 tree rhs1
= gimple_assign_rhs1 (stmt
);
7816 value_range_t
*vr
= get_value_range (rhs1
);
7817 enum machine_mode fltmode
= TYPE_MODE (TREE_TYPE (gimple_assign_lhs (stmt
)));
7818 enum machine_mode mode
;
7822 /* We can only handle constant ranges. */
7823 if (vr
->type
!= VR_RANGE
7824 || TREE_CODE (vr
->min
) != INTEGER_CST
7825 || TREE_CODE (vr
->max
) != INTEGER_CST
)
7828 /* First check if we can use a signed type in place of an unsigned. */
7829 if (TYPE_UNSIGNED (TREE_TYPE (rhs1
))
7830 && (can_float_p (fltmode
, TYPE_MODE (TREE_TYPE (rhs1
)), 0)
7831 != CODE_FOR_nothing
)
7832 && range_fits_type_p (vr
, GET_MODE_PRECISION
7833 (TYPE_MODE (TREE_TYPE (rhs1
))), 0))
7834 mode
= TYPE_MODE (TREE_TYPE (rhs1
));
7835 /* If we can do the conversion in the current input mode do nothing. */
7836 else if (can_float_p (fltmode
, TYPE_MODE (TREE_TYPE (rhs1
)),
7837 TYPE_UNSIGNED (TREE_TYPE (rhs1
))))
7839 /* Otherwise search for a mode we can use, starting from the narrowest
7840 integer mode available. */
7843 mode
= GET_CLASS_NARROWEST_MODE (MODE_INT
);
7846 /* If we cannot do a signed conversion to float from mode
7847 or if the value-range does not fit in the signed type
7848 try with a wider mode. */
7849 if (can_float_p (fltmode
, mode
, 0) != CODE_FOR_nothing
7850 && range_fits_type_p (vr
, GET_MODE_PRECISION (mode
), 0))
7853 mode
= GET_MODE_WIDER_MODE (mode
);
7854 /* But do not widen the input. Instead leave that to the
7855 optabs expansion code. */
7856 if (GET_MODE_PRECISION (mode
) > TYPE_PRECISION (TREE_TYPE (rhs1
)))
7859 while (mode
!= VOIDmode
);
7860 if (mode
== VOIDmode
)
7864 /* It works, insert a truncation or sign-change before the
7865 float conversion. */
7866 tem
= create_tmp_var (build_nonstandard_integer_type
7867 (GET_MODE_PRECISION (mode
), 0), NULL
);
7868 conv
= gimple_build_assign_with_ops (NOP_EXPR
, tem
, rhs1
, NULL_TREE
);
7869 tem
= make_ssa_name (tem
, conv
);
7870 gimple_assign_set_lhs (conv
, tem
);
7871 gsi_insert_before (gsi
, conv
, GSI_SAME_STMT
);
7872 gimple_assign_set_rhs1 (stmt
, tem
);
7878 /* Simplify STMT using ranges if possible. */
7881 simplify_stmt_using_ranges (gimple_stmt_iterator
*gsi
)
7883 gimple stmt
= gsi_stmt (*gsi
);
7884 if (is_gimple_assign (stmt
))
7886 enum tree_code rhs_code
= gimple_assign_rhs_code (stmt
);
7887 tree rhs1
= gimple_assign_rhs1 (stmt
);
7893 /* Transform EQ_EXPR, NE_EXPR into BIT_XOR_EXPR or identity
7894 if the RHS is zero or one, and the LHS are known to be boolean
7896 if (INTEGRAL_TYPE_P (TREE_TYPE (rhs1
)))
7897 return simplify_truth_ops_using_ranges (gsi
, stmt
);
7900 /* Transform TRUNC_DIV_EXPR and TRUNC_MOD_EXPR into RSHIFT_EXPR
7901 and BIT_AND_EXPR respectively if the first operand is greater
7902 than zero and the second operand is an exact power of two. */
7903 case TRUNC_DIV_EXPR
:
7904 case TRUNC_MOD_EXPR
:
7905 if (INTEGRAL_TYPE_P (TREE_TYPE (rhs1
))
7906 && integer_pow2p (gimple_assign_rhs2 (stmt
)))
7907 return simplify_div_or_mod_using_ranges (stmt
);
7910 /* Transform ABS (X) into X or -X as appropriate. */
7912 if (TREE_CODE (rhs1
) == SSA_NAME
7913 && INTEGRAL_TYPE_P (TREE_TYPE (rhs1
)))
7914 return simplify_abs_using_ranges (stmt
);
7919 /* Optimize away BIT_AND_EXPR and BIT_IOR_EXPR
7920 if all the bits being cleared are already cleared or
7921 all the bits being set are already set. */
7922 if (INTEGRAL_TYPE_P (TREE_TYPE (rhs1
)))
7923 return simplify_bit_ops_using_ranges (gsi
, stmt
);
7927 if (TREE_CODE (rhs1
) == SSA_NAME
7928 && INTEGRAL_TYPE_P (TREE_TYPE (rhs1
)))
7929 return simplify_conversion_using_ranges (stmt
);
7933 if (TREE_CODE (rhs1
) == SSA_NAME
7934 && INTEGRAL_TYPE_P (TREE_TYPE (rhs1
)))
7935 return simplify_float_conversion_using_ranges (gsi
, stmt
);
7942 else if (gimple_code (stmt
) == GIMPLE_COND
)
7943 return simplify_cond_using_ranges (stmt
);
7944 else if (gimple_code (stmt
) == GIMPLE_SWITCH
)
7945 return simplify_switch_using_ranges (stmt
);
7950 /* If the statement pointed by SI has a predicate whose value can be
7951 computed using the value range information computed by VRP, compute
7952 its value and return true. Otherwise, return false. */
7955 fold_predicate_in (gimple_stmt_iterator
*si
)
7957 bool assignment_p
= false;
7959 gimple stmt
= gsi_stmt (*si
);
7961 if (is_gimple_assign (stmt
)
7962 && TREE_CODE_CLASS (gimple_assign_rhs_code (stmt
)) == tcc_comparison
)
7964 assignment_p
= true;
7965 val
= vrp_evaluate_conditional (gimple_assign_rhs_code (stmt
),
7966 gimple_assign_rhs1 (stmt
),
7967 gimple_assign_rhs2 (stmt
),
7970 else if (gimple_code (stmt
) == GIMPLE_COND
)
7971 val
= vrp_evaluate_conditional (gimple_cond_code (stmt
),
7972 gimple_cond_lhs (stmt
),
7973 gimple_cond_rhs (stmt
),
7981 val
= fold_convert (gimple_expr_type (stmt
), val
);
7985 fprintf (dump_file
, "Folding predicate ");
7986 print_gimple_expr (dump_file
, stmt
, 0, 0);
7987 fprintf (dump_file
, " to ");
7988 print_generic_expr (dump_file
, val
, 0);
7989 fprintf (dump_file
, "\n");
7992 if (is_gimple_assign (stmt
))
7993 gimple_assign_set_rhs_from_tree (si
, val
);
7996 gcc_assert (gimple_code (stmt
) == GIMPLE_COND
);
7997 if (integer_zerop (val
))
7998 gimple_cond_make_false (stmt
);
7999 else if (integer_onep (val
))
8000 gimple_cond_make_true (stmt
);
8011 /* Callback for substitute_and_fold folding the stmt at *SI. */
8014 vrp_fold_stmt (gimple_stmt_iterator
*si
)
8016 if (fold_predicate_in (si
))
8019 return simplify_stmt_using_ranges (si
);
8022 /* Stack of dest,src equivalency pairs that need to be restored after
8023 each attempt to thread a block's incoming edge to an outgoing edge.
8025 A NULL entry is used to mark the end of pairs which need to be
8027 static VEC(tree
,heap
) *stack
;
8029 /* A trivial wrapper so that we can present the generic jump threading
8030 code with a simple API for simplifying statements. STMT is the
8031 statement we want to simplify, WITHIN_STMT provides the location
8032 for any overflow warnings. */
8035 simplify_stmt_for_jump_threading (gimple stmt
, gimple within_stmt
)
8037 /* We only use VRP information to simplify conditionals. This is
8038 overly conservative, but it's unclear if doing more would be
8039 worth the compile time cost. */
8040 if (gimple_code (stmt
) != GIMPLE_COND
)
8043 return vrp_evaluate_conditional (gimple_cond_code (stmt
),
8044 gimple_cond_lhs (stmt
),
8045 gimple_cond_rhs (stmt
), within_stmt
);
8048 /* Blocks which have more than one predecessor and more than
8049 one successor present jump threading opportunities, i.e.,
8050 when the block is reached from a specific predecessor, we
8051 may be able to determine which of the outgoing edges will
8052 be traversed. When this optimization applies, we are able
8053 to avoid conditionals at runtime and we may expose secondary
8054 optimization opportunities.
8056 This routine is effectively a driver for the generic jump
8057 threading code. It basically just presents the generic code
8058 with edges that may be suitable for jump threading.
8060 Unlike DOM, we do not iterate VRP if jump threading was successful.
8061 While iterating may expose new opportunities for VRP, it is expected
8062 those opportunities would be very limited and the compile time cost
8063 to expose those opportunities would be significant.
8065 As jump threading opportunities are discovered, they are registered
8066 for later realization. */
8069 identify_jump_threads (void)
8076 /* Ugh. When substituting values earlier in this pass we can
8077 wipe the dominance information. So rebuild the dominator
8078 information as we need it within the jump threading code. */
8079 calculate_dominance_info (CDI_DOMINATORS
);
8081 /* We do not allow VRP information to be used for jump threading
8082 across a back edge in the CFG. Otherwise it becomes too
8083 difficult to avoid eliminating loop exit tests. Of course
8084 EDGE_DFS_BACK is not accurate at this time so we have to
8086 mark_dfs_back_edges ();
8088 /* Do not thread across edges we are about to remove. Just marking
8089 them as EDGE_DFS_BACK will do. */
8090 FOR_EACH_VEC_ELT (edge
, to_remove_edges
, i
, e
)
8091 e
->flags
|= EDGE_DFS_BACK
;
8093 /* Allocate our unwinder stack to unwind any temporary equivalences
8094 that might be recorded. */
8095 stack
= VEC_alloc (tree
, heap
, 20);
8097 /* To avoid lots of silly node creation, we create a single
8098 conditional and just modify it in-place when attempting to
8100 dummy
= gimple_build_cond (EQ_EXPR
,
8101 integer_zero_node
, integer_zero_node
,
8104 /* Walk through all the blocks finding those which present a
8105 potential jump threading opportunity. We could set this up
8106 as a dominator walker and record data during the walk, but
8107 I doubt it's worth the effort for the classes of jump
8108 threading opportunities we are trying to identify at this
8109 point in compilation. */
8114 /* If the generic jump threading code does not find this block
8115 interesting, then there is nothing to do. */
8116 if (! potentially_threadable_block (bb
))
8119 /* We only care about blocks ending in a COND_EXPR. While there
8120 may be some value in handling SWITCH_EXPR here, I doubt it's
8121 terribly important. */
8122 last
= gsi_stmt (gsi_last_bb (bb
));
8124 /* We're basically looking for a switch or any kind of conditional with
8125 integral or pointer type arguments. Note the type of the second
8126 argument will be the same as the first argument, so no need to
8127 check it explicitly. */
8128 if (gimple_code (last
) == GIMPLE_SWITCH
8129 || (gimple_code (last
) == GIMPLE_COND
8130 && TREE_CODE (gimple_cond_lhs (last
)) == SSA_NAME
8131 && (INTEGRAL_TYPE_P (TREE_TYPE (gimple_cond_lhs (last
)))
8132 || POINTER_TYPE_P (TREE_TYPE (gimple_cond_lhs (last
))))
8133 && (TREE_CODE (gimple_cond_rhs (last
)) == SSA_NAME
8134 || is_gimple_min_invariant (gimple_cond_rhs (last
)))))
8138 /* We've got a block with multiple predecessors and multiple
8139 successors which also ends in a suitable conditional or
8140 switch statement. For each predecessor, see if we can thread
8141 it to a specific successor. */
8142 FOR_EACH_EDGE (e
, ei
, bb
->preds
)
8144 /* Do not thread across back edges or abnormal edges
8146 if (e
->flags
& (EDGE_DFS_BACK
| EDGE_COMPLEX
))
8149 thread_across_edge (dummy
, e
, true, &stack
,
8150 simplify_stmt_for_jump_threading
);
8155 /* We do not actually update the CFG or SSA graphs at this point as
8156 ASSERT_EXPRs are still in the IL and cfg cleanup code does not yet
8157 handle ASSERT_EXPRs gracefully. */
8160 /* We identified all the jump threading opportunities earlier, but could
8161 not transform the CFG at that time. This routine transforms the
8162 CFG and arranges for the dominator tree to be rebuilt if necessary.
8164 Note the SSA graph update will occur during the normal TODO
8165 processing by the pass manager. */
8167 finalize_jump_threads (void)
8169 thread_through_all_blocks (false);
8170 VEC_free (tree
, heap
, stack
);
8174 /* Traverse all the blocks folding conditionals with known ranges. */
8181 values_propagated
= true;
8185 fprintf (dump_file
, "\nValue ranges after VRP:\n\n");
8186 dump_all_value_ranges (dump_file
);
8187 fprintf (dump_file
, "\n");
8190 substitute_and_fold (op_with_constant_singleton_value_range
,
8191 vrp_fold_stmt
, false);
8193 if (warn_array_bounds
)
8194 check_all_array_refs ();
8196 /* We must identify jump threading opportunities before we release
8197 the datastructures built by VRP. */
8198 identify_jump_threads ();
8200 /* Free allocated memory. */
8201 for (i
= 0; i
< num_vr_values
; i
++)
8204 BITMAP_FREE (vr_value
[i
]->equiv
);
8209 free (vr_phi_edge_counts
);
8211 /* So that we can distinguish between VRP data being available
8212 and not available. */
8214 vr_phi_edge_counts
= NULL
;
8218 /* Main entry point to VRP (Value Range Propagation). This pass is
8219 loosely based on J. R. C. Patterson, ``Accurate Static Branch
8220 Prediction by Value Range Propagation,'' in SIGPLAN Conference on
8221 Programming Language Design and Implementation, pp. 67-78, 1995.
8222 Also available at http://citeseer.ist.psu.edu/patterson95accurate.html
8224 This is essentially an SSA-CCP pass modified to deal with ranges
8225 instead of constants.
8227 While propagating ranges, we may find that two or more SSA name
8228 have equivalent, though distinct ranges. For instance,
8231 2 p_4 = ASSERT_EXPR <p_3, p_3 != 0>
8233 4 p_5 = ASSERT_EXPR <p_4, p_4 == q_2>;
8237 In the code above, pointer p_5 has range [q_2, q_2], but from the
8238 code we can also determine that p_5 cannot be NULL and, if q_2 had
8239 a non-varying range, p_5's range should also be compatible with it.
8241 These equivalences are created by two expressions: ASSERT_EXPR and
8242 copy operations. Since p_5 is an assertion on p_4, and p_4 was the
8243 result of another assertion, then we can use the fact that p_5 and
8244 p_4 are equivalent when evaluating p_5's range.
8246 Together with value ranges, we also propagate these equivalences
8247 between names so that we can take advantage of information from
8248 multiple ranges when doing final replacement. Note that this
8249 equivalency relation is transitive but not symmetric.
8251 In the example above, p_5 is equivalent to p_4, q_2 and p_3, but we
8252 cannot assert that q_2 is equivalent to p_5 because q_2 may be used
8253 in contexts where that assertion does not hold (e.g., in line 6).
8255 TODO, the main difference between this pass and Patterson's is that
8256 we do not propagate edge probabilities. We only compute whether
8257 edges can be taken or not. That is, instead of having a spectrum
8258 of jump probabilities between 0 and 1, we only deal with 0, 1 and
8259 DON'T KNOW. In the future, it may be worthwhile to propagate
8260 probabilities to aid branch prediction. */
8269 loop_optimizer_init (LOOPS_NORMAL
| LOOPS_HAVE_RECORDED_EXITS
);
8270 rewrite_into_loop_closed_ssa (NULL
, TODO_update_ssa
);
8273 insert_range_assertions ();
8275 /* Estimate number of iterations - but do not use undefined behavior
8276 for this. We can't do this lazily as other functions may compute
8277 this using undefined behavior. */
8278 free_numbers_of_iterations_estimates ();
8279 estimate_numbers_of_iterations (false);
8281 to_remove_edges
= VEC_alloc (edge
, heap
, 10);
8282 to_update_switch_stmts
= VEC_alloc (switch_update
, heap
, 5);
8283 threadedge_initialize_values ();
8286 ssa_propagate (vrp_visit_stmt
, vrp_visit_phi_node
);
8289 free_numbers_of_iterations_estimates ();
8291 /* ASSERT_EXPRs must be removed before finalizing jump threads
8292 as finalizing jump threads calls the CFG cleanup code which
8293 does not properly handle ASSERT_EXPRs. */
8294 remove_range_assertions ();
8296 /* If we exposed any new variables, go ahead and put them into
8297 SSA form now, before we handle jump threading. This simplifies
8298 interactions between rewriting of _DECL nodes into SSA form
8299 and rewriting SSA_NAME nodes into SSA form after block
8300 duplication and CFG manipulation. */
8301 update_ssa (TODO_update_ssa
);
8303 finalize_jump_threads ();
8305 /* Remove dead edges from SWITCH_EXPR optimization. This leaves the
8306 CFG in a broken state and requires a cfg_cleanup run. */
8307 FOR_EACH_VEC_ELT (edge
, to_remove_edges
, i
, e
)
8309 /* Update SWITCH_EXPR case label vector. */
8310 FOR_EACH_VEC_ELT (switch_update
, to_update_switch_stmts
, i
, su
)
8313 size_t n
= TREE_VEC_LENGTH (su
->vec
);
8315 gimple_switch_set_num_labels (su
->stmt
, n
);
8316 for (j
= 0; j
< n
; j
++)
8317 gimple_switch_set_label (su
->stmt
, j
, TREE_VEC_ELT (su
->vec
, j
));
8318 /* As we may have replaced the default label with a regular one
8319 make sure to make it a real default label again. This ensures
8320 optimal expansion. */
8321 label
= gimple_switch_default_label (su
->stmt
);
8322 CASE_LOW (label
) = NULL_TREE
;
8323 CASE_HIGH (label
) = NULL_TREE
;
8326 if (VEC_length (edge
, to_remove_edges
) > 0)
8327 free_dominance_info (CDI_DOMINATORS
);
8329 VEC_free (edge
, heap
, to_remove_edges
);
8330 VEC_free (switch_update
, heap
, to_update_switch_stmts
);
8331 threadedge_finalize_values ();
8334 loop_optimizer_finalize ();
8341 return flag_tree_vrp
!= 0;
8344 struct gimple_opt_pass pass_vrp
=
8349 gate_vrp
, /* gate */
8350 execute_vrp
, /* execute */
8353 0, /* static_pass_number */
8354 TV_TREE_VRP
, /* tv_id */
8355 PROP_ssa
, /* properties_required */
8356 0, /* properties_provided */
8357 0, /* properties_destroyed */
8358 0, /* todo_flags_start */
8363 | TODO_ggc_collect
/* todo_flags_finish */