1 /* Support routines for Value Range Propagation (VRP).
2 Copyright (C) 2005, 2006, 2007, 2008, 2009 Free Software Foundation, Inc.
3 Contributed by Diego Novillo <dnovillo@redhat.com>.
5 This file is part of GCC.
7 GCC is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 3, or (at your option)
12 GCC is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with GCC; see the file COPYING3. If not see
19 <http://www.gnu.org/licenses/>. */
23 #include "coretypes.h"
28 #include "basic-block.h"
29 #include "tree-flow.h"
30 #include "tree-pass.h"
31 #include "tree-dump.h"
33 #include "diagnostic.h"
37 #include "tree-scalar-evolution.h"
38 #include "tree-ssa-propagate.h"
39 #include "tree-chrec.h"
42 /* Set of SSA names found live during the RPO traversal of the function
43 for still active basic-blocks. */
46 /* Return true if the SSA name NAME is live on the edge E. */
49 live_on_edge (edge e
, tree name
)
51 return (live
[e
->dest
->index
]
52 && TEST_BIT (live
[e
->dest
->index
], SSA_NAME_VERSION (name
)));
55 /* Local functions. */
56 static int compare_values (tree val1
, tree val2
);
57 static int compare_values_warnv (tree val1
, tree val2
, bool *);
58 static void vrp_meet (value_range_t
*, value_range_t
*);
59 static tree
vrp_evaluate_conditional_warnv_with_ops (enum tree_code
,
60 tree
, tree
, bool, bool *,
63 /* Location information for ASSERT_EXPRs. Each instance of this
64 structure describes an ASSERT_EXPR for an SSA name. Since a single
65 SSA name may have more than one assertion associated with it, these
66 locations are kept in a linked list attached to the corresponding
70 /* Basic block where the assertion would be inserted. */
73 /* Some assertions need to be inserted on an edge (e.g., assertions
74 generated by COND_EXPRs). In those cases, BB will be NULL. */
77 /* Pointer to the statement that generated this assertion. */
78 gimple_stmt_iterator si
;
80 /* Predicate code for the ASSERT_EXPR. Must be COMPARISON_CLASS_P. */
81 enum tree_code comp_code
;
83 /* Value being compared against. */
86 /* Expression to compare. */
89 /* Next node in the linked list. */
90 struct assert_locus_d
*next
;
93 typedef struct assert_locus_d
*assert_locus_t
;
95 /* If bit I is present, it means that SSA name N_i has a list of
96 assertions that should be inserted in the IL. */
97 static bitmap need_assert_for
;
99 /* Array of locations lists where to insert assertions. ASSERTS_FOR[I]
100 holds a list of ASSERT_LOCUS_T nodes that describe where
101 ASSERT_EXPRs for SSA name N_I should be inserted. */
102 static assert_locus_t
*asserts_for
;
104 /* Value range array. After propagation, VR_VALUE[I] holds the range
105 of values that SSA name N_I may take. */
106 static value_range_t
**vr_value
;
108 /* For a PHI node which sets SSA name N_I, VR_COUNTS[I] holds the
109 number of executable edges we saw the last time we visited the
111 static int *vr_phi_edge_counts
;
118 static VEC (edge
, heap
) *to_remove_edges
;
119 DEF_VEC_O(switch_update
);
120 DEF_VEC_ALLOC_O(switch_update
, heap
);
121 static VEC (switch_update
, heap
) *to_update_switch_stmts
;
124 /* Return the maximum value for TYPE. */
127 vrp_val_max (const_tree type
)
129 if (!INTEGRAL_TYPE_P (type
))
132 return TYPE_MAX_VALUE (type
);
135 /* Return the minimum value for TYPE. */
138 vrp_val_min (const_tree type
)
140 if (!INTEGRAL_TYPE_P (type
))
143 return TYPE_MIN_VALUE (type
);
146 /* Return whether VAL is equal to the maximum value of its type. This
147 will be true for a positive overflow infinity. We can't do a
148 simple equality comparison with TYPE_MAX_VALUE because C typedefs
149 and Ada subtypes can produce types whose TYPE_MAX_VALUE is not ==
150 to the integer constant with the same value in the type. */
153 vrp_val_is_max (const_tree val
)
155 tree type_max
= vrp_val_max (TREE_TYPE (val
));
156 return (val
== type_max
157 || (type_max
!= NULL_TREE
158 && operand_equal_p (val
, type_max
, 0)));
161 /* Return whether VAL is equal to the minimum value of its type. This
162 will be true for a negative overflow infinity. */
165 vrp_val_is_min (const_tree val
)
167 tree type_min
= vrp_val_min (TREE_TYPE (val
));
168 return (val
== type_min
169 || (type_min
!= NULL_TREE
170 && operand_equal_p (val
, type_min
, 0)));
174 /* Return whether TYPE should use an overflow infinity distinct from
175 TYPE_{MIN,MAX}_VALUE. We use an overflow infinity value to
176 represent a signed overflow during VRP computations. An infinity
177 is distinct from a half-range, which will go from some number to
178 TYPE_{MIN,MAX}_VALUE. */
181 needs_overflow_infinity (const_tree type
)
183 return INTEGRAL_TYPE_P (type
) && !TYPE_OVERFLOW_WRAPS (type
);
186 /* Return whether TYPE can support our overflow infinity
187 representation: we use the TREE_OVERFLOW flag, which only exists
188 for constants. If TYPE doesn't support this, we don't optimize
189 cases which would require signed overflow--we drop them to
193 supports_overflow_infinity (const_tree type
)
195 tree min
= vrp_val_min (type
), max
= vrp_val_max (type
);
196 #ifdef ENABLE_CHECKING
197 gcc_assert (needs_overflow_infinity (type
));
199 return (min
!= NULL_TREE
200 && CONSTANT_CLASS_P (min
)
202 && CONSTANT_CLASS_P (max
));
205 /* VAL is the maximum or minimum value of a type. Return a
206 corresponding overflow infinity. */
209 make_overflow_infinity (tree val
)
211 #ifdef ENABLE_CHECKING
212 gcc_assert (val
!= NULL_TREE
&& CONSTANT_CLASS_P (val
));
214 val
= copy_node (val
);
215 TREE_OVERFLOW (val
) = 1;
219 /* Return a negative overflow infinity for TYPE. */
222 negative_overflow_infinity (tree type
)
224 #ifdef ENABLE_CHECKING
225 gcc_assert (supports_overflow_infinity (type
));
227 return make_overflow_infinity (vrp_val_min (type
));
230 /* Return a positive overflow infinity for TYPE. */
233 positive_overflow_infinity (tree type
)
235 #ifdef ENABLE_CHECKING
236 gcc_assert (supports_overflow_infinity (type
));
238 return make_overflow_infinity (vrp_val_max (type
));
241 /* Return whether VAL is a negative overflow infinity. */
244 is_negative_overflow_infinity (const_tree val
)
246 return (needs_overflow_infinity (TREE_TYPE (val
))
247 && CONSTANT_CLASS_P (val
)
248 && TREE_OVERFLOW (val
)
249 && vrp_val_is_min (val
));
252 /* Return whether VAL is a positive overflow infinity. */
255 is_positive_overflow_infinity (const_tree val
)
257 return (needs_overflow_infinity (TREE_TYPE (val
))
258 && CONSTANT_CLASS_P (val
)
259 && TREE_OVERFLOW (val
)
260 && vrp_val_is_max (val
));
263 /* Return whether VAL is a positive or negative overflow infinity. */
266 is_overflow_infinity (const_tree val
)
268 return (needs_overflow_infinity (TREE_TYPE (val
))
269 && CONSTANT_CLASS_P (val
)
270 && TREE_OVERFLOW (val
)
271 && (vrp_val_is_min (val
) || vrp_val_is_max (val
)));
274 /* Return whether STMT has a constant rhs that is_overflow_infinity. */
277 stmt_overflow_infinity (gimple stmt
)
279 if (is_gimple_assign (stmt
)
280 && get_gimple_rhs_class (gimple_assign_rhs_code (stmt
)) ==
282 return is_overflow_infinity (gimple_assign_rhs1 (stmt
));
286 /* If VAL is now an overflow infinity, return VAL. Otherwise, return
287 the same value with TREE_OVERFLOW clear. This can be used to avoid
288 confusing a regular value with an overflow value. */
291 avoid_overflow_infinity (tree val
)
293 if (!is_overflow_infinity (val
))
296 if (vrp_val_is_max (val
))
297 return vrp_val_max (TREE_TYPE (val
));
300 #ifdef ENABLE_CHECKING
301 gcc_assert (vrp_val_is_min (val
));
303 return vrp_val_min (TREE_TYPE (val
));
308 /* Return true if ARG is marked with the nonnull attribute in the
309 current function signature. */
312 nonnull_arg_p (const_tree arg
)
314 tree t
, attrs
, fntype
;
315 unsigned HOST_WIDE_INT arg_num
;
317 gcc_assert (TREE_CODE (arg
) == PARM_DECL
&& POINTER_TYPE_P (TREE_TYPE (arg
)));
319 /* The static chain decl is always non null. */
320 if (arg
== cfun
->static_chain_decl
)
323 fntype
= TREE_TYPE (current_function_decl
);
324 attrs
= lookup_attribute ("nonnull", TYPE_ATTRIBUTES (fntype
));
326 /* If "nonnull" wasn't specified, we know nothing about the argument. */
327 if (attrs
== NULL_TREE
)
330 /* If "nonnull" applies to all the arguments, then ARG is non-null. */
331 if (TREE_VALUE (attrs
) == NULL_TREE
)
334 /* Get the position number for ARG in the function signature. */
335 for (arg_num
= 1, t
= DECL_ARGUMENTS (current_function_decl
);
337 t
= TREE_CHAIN (t
), arg_num
++)
343 gcc_assert (t
== arg
);
345 /* Now see if ARG_NUM is mentioned in the nonnull list. */
346 for (t
= TREE_VALUE (attrs
); t
; t
= TREE_CHAIN (t
))
348 if (compare_tree_int (TREE_VALUE (t
), arg_num
) == 0)
356 /* Set value range VR to VR_VARYING. */
359 set_value_range_to_varying (value_range_t
*vr
)
361 vr
->type
= VR_VARYING
;
362 vr
->min
= vr
->max
= NULL_TREE
;
364 bitmap_clear (vr
->equiv
);
368 /* Set value range VR to {T, MIN, MAX, EQUIV}. */
371 set_value_range (value_range_t
*vr
, enum value_range_type t
, tree min
,
372 tree max
, bitmap equiv
)
374 #if defined ENABLE_CHECKING
375 /* Check the validity of the range. */
376 if (t
== VR_RANGE
|| t
== VR_ANTI_RANGE
)
380 gcc_assert (min
&& max
);
382 if (INTEGRAL_TYPE_P (TREE_TYPE (min
)) && t
== VR_ANTI_RANGE
)
383 gcc_assert (!vrp_val_is_min (min
) || !vrp_val_is_max (max
));
385 cmp
= compare_values (min
, max
);
386 gcc_assert (cmp
== 0 || cmp
== -1 || cmp
== -2);
388 if (needs_overflow_infinity (TREE_TYPE (min
)))
389 gcc_assert (!is_overflow_infinity (min
)
390 || !is_overflow_infinity (max
));
393 if (t
== VR_UNDEFINED
|| t
== VR_VARYING
)
394 gcc_assert (min
== NULL_TREE
&& max
== NULL_TREE
);
396 if (t
== VR_UNDEFINED
|| t
== VR_VARYING
)
397 gcc_assert (equiv
== NULL
|| bitmap_empty_p (equiv
));
404 /* Since updating the equivalence set involves deep copying the
405 bitmaps, only do it if absolutely necessary. */
406 if (vr
->equiv
== NULL
408 vr
->equiv
= BITMAP_ALLOC (NULL
);
410 if (equiv
!= vr
->equiv
)
412 if (equiv
&& !bitmap_empty_p (equiv
))
413 bitmap_copy (vr
->equiv
, equiv
);
415 bitmap_clear (vr
->equiv
);
420 /* Set value range VR to the canonical form of {T, MIN, MAX, EQUIV}.
421 This means adjusting T, MIN and MAX representing the case of a
422 wrapping range with MAX < MIN covering [MIN, type_max] U [type_min, MAX]
423 as anti-rage ~[MAX+1, MIN-1]. Likewise for wrapping anti-ranges.
424 In corner cases where MAX+1 or MIN-1 wraps this will fall back
426 This routine exists to ease canonicalization in the case where we
427 extract ranges from var + CST op limit. */
430 set_and_canonicalize_value_range (value_range_t
*vr
, enum value_range_type t
,
431 tree min
, tree max
, bitmap equiv
)
433 /* Nothing to canonicalize for symbolic or unknown or varying ranges. */
435 && t
!= VR_ANTI_RANGE
)
436 || TREE_CODE (min
) != INTEGER_CST
437 || TREE_CODE (max
) != INTEGER_CST
)
439 set_value_range (vr
, t
, min
, max
, equiv
);
443 /* Wrong order for min and max, to swap them and the VR type we need
445 if (tree_int_cst_lt (max
, min
))
447 tree one
= build_int_cst (TREE_TYPE (min
), 1);
448 tree tmp
= int_const_binop (PLUS_EXPR
, max
, one
, 0);
449 max
= int_const_binop (MINUS_EXPR
, min
, one
, 0);
452 /* There's one corner case, if we had [C+1, C] before we now have
453 that again. But this represents an empty value range, so drop
454 to varying in this case. */
455 if (tree_int_cst_lt (max
, min
))
457 set_value_range_to_varying (vr
);
461 t
= t
== VR_RANGE
? VR_ANTI_RANGE
: VR_RANGE
;
464 /* Anti-ranges that can be represented as ranges should be so. */
465 if (t
== VR_ANTI_RANGE
)
467 bool is_min
= vrp_val_is_min (min
);
468 bool is_max
= vrp_val_is_max (max
);
470 if (is_min
&& is_max
)
472 /* We cannot deal with empty ranges, drop to varying. */
473 set_value_range_to_varying (vr
);
477 /* As a special exception preserve non-null ranges. */
478 && !(TYPE_UNSIGNED (TREE_TYPE (min
))
479 && integer_zerop (max
)))
481 tree one
= build_int_cst (TREE_TYPE (max
), 1);
482 min
= int_const_binop (PLUS_EXPR
, max
, one
, 0);
483 max
= vrp_val_max (TREE_TYPE (max
));
488 tree one
= build_int_cst (TREE_TYPE (min
), 1);
489 max
= int_const_binop (MINUS_EXPR
, min
, one
, 0);
490 min
= vrp_val_min (TREE_TYPE (min
));
495 set_value_range (vr
, t
, min
, max
, equiv
);
498 /* Copy value range FROM into value range TO. */
501 copy_value_range (value_range_t
*to
, value_range_t
*from
)
503 set_value_range (to
, from
->type
, from
->min
, from
->max
, from
->equiv
);
506 /* Set value range VR to a single value. This function is only called
507 with values we get from statements, and exists to clear the
508 TREE_OVERFLOW flag so that we don't think we have an overflow
509 infinity when we shouldn't. */
512 set_value_range_to_value (value_range_t
*vr
, tree val
, bitmap equiv
)
514 gcc_assert (is_gimple_min_invariant (val
));
515 val
= avoid_overflow_infinity (val
);
516 set_value_range (vr
, VR_RANGE
, val
, val
, equiv
);
519 /* Set value range VR to a non-negative range of type TYPE.
520 OVERFLOW_INFINITY indicates whether to use an overflow infinity
521 rather than TYPE_MAX_VALUE; this should be true if we determine
522 that the range is nonnegative based on the assumption that signed
523 overflow does not occur. */
526 set_value_range_to_nonnegative (value_range_t
*vr
, tree type
,
527 bool overflow_infinity
)
531 if (overflow_infinity
&& !supports_overflow_infinity (type
))
533 set_value_range_to_varying (vr
);
537 zero
= build_int_cst (type
, 0);
538 set_value_range (vr
, VR_RANGE
, zero
,
540 ? positive_overflow_infinity (type
)
541 : TYPE_MAX_VALUE (type
)),
545 /* Set value range VR to a non-NULL range of type TYPE. */
548 set_value_range_to_nonnull (value_range_t
*vr
, tree type
)
550 tree zero
= build_int_cst (type
, 0);
551 set_value_range (vr
, VR_ANTI_RANGE
, zero
, zero
, vr
->equiv
);
555 /* Set value range VR to a NULL range of type TYPE. */
558 set_value_range_to_null (value_range_t
*vr
, tree type
)
560 set_value_range_to_value (vr
, build_int_cst (type
, 0), vr
->equiv
);
564 /* Set value range VR to a range of a truthvalue of type TYPE. */
567 set_value_range_to_truthvalue (value_range_t
*vr
, tree type
)
569 if (TYPE_PRECISION (type
) == 1)
570 set_value_range_to_varying (vr
);
572 set_value_range (vr
, VR_RANGE
,
573 build_int_cst (type
, 0), build_int_cst (type
, 1),
578 /* Set value range VR to VR_UNDEFINED. */
581 set_value_range_to_undefined (value_range_t
*vr
)
583 vr
->type
= VR_UNDEFINED
;
584 vr
->min
= vr
->max
= NULL_TREE
;
586 bitmap_clear (vr
->equiv
);
590 /* If abs (min) < abs (max), set VR to [-max, max], if
591 abs (min) >= abs (max), set VR to [-min, min]. */
594 abs_extent_range (value_range_t
*vr
, tree min
, tree max
)
598 gcc_assert (TREE_CODE (min
) == INTEGER_CST
);
599 gcc_assert (TREE_CODE (max
) == INTEGER_CST
);
600 gcc_assert (INTEGRAL_TYPE_P (TREE_TYPE (min
)));
601 gcc_assert (!TYPE_UNSIGNED (TREE_TYPE (min
)));
602 min
= fold_unary (ABS_EXPR
, TREE_TYPE (min
), min
);
603 max
= fold_unary (ABS_EXPR
, TREE_TYPE (max
), max
);
604 if (TREE_OVERFLOW (min
) || TREE_OVERFLOW (max
))
606 set_value_range_to_varying (vr
);
609 cmp
= compare_values (min
, max
);
611 min
= fold_unary (NEGATE_EXPR
, TREE_TYPE (min
), max
);
612 else if (cmp
== 0 || cmp
== 1)
615 min
= fold_unary (NEGATE_EXPR
, TREE_TYPE (min
), min
);
619 set_value_range_to_varying (vr
);
622 set_and_canonicalize_value_range (vr
, VR_RANGE
, min
, max
, NULL
);
626 /* Return value range information for VAR.
628 If we have no values ranges recorded (ie, VRP is not running), then
629 return NULL. Otherwise create an empty range if none existed for VAR. */
631 static value_range_t
*
632 get_value_range (const_tree var
)
636 unsigned ver
= SSA_NAME_VERSION (var
);
638 /* If we have no recorded ranges, then return NULL. */
646 /* Create a default value range. */
647 vr_value
[ver
] = vr
= XCNEW (value_range_t
);
649 /* Defer allocating the equivalence set. */
652 /* If VAR is a default definition, the variable can take any value
654 sym
= SSA_NAME_VAR (var
);
655 if (SSA_NAME_IS_DEFAULT_DEF (var
))
657 /* Try to use the "nonnull" attribute to create ~[0, 0]
658 anti-ranges for pointers. Note that this is only valid with
659 default definitions of PARM_DECLs. */
660 if (TREE_CODE (sym
) == PARM_DECL
661 && POINTER_TYPE_P (TREE_TYPE (sym
))
662 && nonnull_arg_p (sym
))
663 set_value_range_to_nonnull (vr
, TREE_TYPE (sym
));
665 set_value_range_to_varying (vr
);
671 /* Return true, if VAL1 and VAL2 are equal values for VRP purposes. */
674 vrp_operand_equal_p (const_tree val1
, const_tree val2
)
678 if (!val1
|| !val2
|| !operand_equal_p (val1
, val2
, 0))
680 if (is_overflow_infinity (val1
))
681 return is_overflow_infinity (val2
);
685 /* Return true, if the bitmaps B1 and B2 are equal. */
688 vrp_bitmap_equal_p (const_bitmap b1
, const_bitmap b2
)
692 && bitmap_equal_p (b1
, b2
)));
695 /* Update the value range and equivalence set for variable VAR to
696 NEW_VR. Return true if NEW_VR is different from VAR's previous
699 NOTE: This function assumes that NEW_VR is a temporary value range
700 object created for the sole purpose of updating VAR's range. The
701 storage used by the equivalence set from NEW_VR will be freed by
702 this function. Do not call update_value_range when NEW_VR
703 is the range object associated with another SSA name. */
706 update_value_range (const_tree var
, value_range_t
*new_vr
)
708 value_range_t
*old_vr
;
711 /* Update the value range, if necessary. */
712 old_vr
= get_value_range (var
);
713 is_new
= old_vr
->type
!= new_vr
->type
714 || !vrp_operand_equal_p (old_vr
->min
, new_vr
->min
)
715 || !vrp_operand_equal_p (old_vr
->max
, new_vr
->max
)
716 || !vrp_bitmap_equal_p (old_vr
->equiv
, new_vr
->equiv
);
719 set_value_range (old_vr
, new_vr
->type
, new_vr
->min
, new_vr
->max
,
722 BITMAP_FREE (new_vr
->equiv
);
728 /* Add VAR and VAR's equivalence set to EQUIV. This is the central
729 point where equivalence processing can be turned on/off. */
732 add_equivalence (bitmap
*equiv
, const_tree var
)
734 unsigned ver
= SSA_NAME_VERSION (var
);
735 value_range_t
*vr
= vr_value
[ver
];
738 *equiv
= BITMAP_ALLOC (NULL
);
739 bitmap_set_bit (*equiv
, ver
);
741 bitmap_ior_into (*equiv
, vr
->equiv
);
745 /* Return true if VR is ~[0, 0]. */
748 range_is_nonnull (value_range_t
*vr
)
750 return vr
->type
== VR_ANTI_RANGE
751 && integer_zerop (vr
->min
)
752 && integer_zerop (vr
->max
);
756 /* Return true if VR is [0, 0]. */
759 range_is_null (value_range_t
*vr
)
761 return vr
->type
== VR_RANGE
762 && integer_zerop (vr
->min
)
763 && integer_zerop (vr
->max
);
767 /* Return true if value range VR involves at least one symbol. */
770 symbolic_range_p (value_range_t
*vr
)
772 return (!is_gimple_min_invariant (vr
->min
)
773 || !is_gimple_min_invariant (vr
->max
));
776 /* Return true if value range VR uses an overflow infinity. */
779 overflow_infinity_range_p (value_range_t
*vr
)
781 return (vr
->type
== VR_RANGE
782 && (is_overflow_infinity (vr
->min
)
783 || is_overflow_infinity (vr
->max
)));
786 /* Return false if we can not make a valid comparison based on VR;
787 this will be the case if it uses an overflow infinity and overflow
788 is not undefined (i.e., -fno-strict-overflow is in effect).
789 Otherwise return true, and set *STRICT_OVERFLOW_P to true if VR
790 uses an overflow infinity. */
793 usable_range_p (value_range_t
*vr
, bool *strict_overflow_p
)
795 gcc_assert (vr
->type
== VR_RANGE
);
796 if (is_overflow_infinity (vr
->min
))
798 *strict_overflow_p
= true;
799 if (!TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (vr
->min
)))
802 if (is_overflow_infinity (vr
->max
))
804 *strict_overflow_p
= true;
805 if (!TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (vr
->max
)))
812 /* Like tree_expr_nonnegative_warnv_p, but this function uses value
813 ranges obtained so far. */
816 vrp_expr_computes_nonnegative (tree expr
, bool *strict_overflow_p
)
818 return (tree_expr_nonnegative_warnv_p (expr
, strict_overflow_p
)
819 || (TREE_CODE (expr
) == SSA_NAME
820 && ssa_name_nonnegative_p (expr
)));
823 /* Return true if the result of assignment STMT is know to be non-negative.
824 If the return value is based on the assumption that signed overflow is
825 undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't change
826 *STRICT_OVERFLOW_P.*/
829 gimple_assign_nonnegative_warnv_p (gimple stmt
, bool *strict_overflow_p
)
831 enum tree_code code
= gimple_assign_rhs_code (stmt
);
832 switch (get_gimple_rhs_class (code
))
834 case GIMPLE_UNARY_RHS
:
835 return tree_unary_nonnegative_warnv_p (gimple_assign_rhs_code (stmt
),
836 gimple_expr_type (stmt
),
837 gimple_assign_rhs1 (stmt
),
839 case GIMPLE_BINARY_RHS
:
840 return tree_binary_nonnegative_warnv_p (gimple_assign_rhs_code (stmt
),
841 gimple_expr_type (stmt
),
842 gimple_assign_rhs1 (stmt
),
843 gimple_assign_rhs2 (stmt
),
845 case GIMPLE_SINGLE_RHS
:
846 return tree_single_nonnegative_warnv_p (gimple_assign_rhs1 (stmt
),
848 case GIMPLE_INVALID_RHS
:
855 /* Return true if return value of call STMT is know to be non-negative.
856 If the return value is based on the assumption that signed overflow is
857 undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't change
858 *STRICT_OVERFLOW_P.*/
861 gimple_call_nonnegative_warnv_p (gimple stmt
, bool *strict_overflow_p
)
863 tree arg0
= gimple_call_num_args (stmt
) > 0 ?
864 gimple_call_arg (stmt
, 0) : NULL_TREE
;
865 tree arg1
= gimple_call_num_args (stmt
) > 1 ?
866 gimple_call_arg (stmt
, 1) : NULL_TREE
;
868 return tree_call_nonnegative_warnv_p (gimple_expr_type (stmt
),
869 gimple_call_fndecl (stmt
),
875 /* Return true if STMT is know to to compute a non-negative value.
876 If the return value is based on the assumption that signed overflow is
877 undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't change
878 *STRICT_OVERFLOW_P.*/
881 gimple_stmt_nonnegative_warnv_p (gimple stmt
, bool *strict_overflow_p
)
883 switch (gimple_code (stmt
))
886 return gimple_assign_nonnegative_warnv_p (stmt
, strict_overflow_p
);
888 return gimple_call_nonnegative_warnv_p (stmt
, strict_overflow_p
);
894 /* Return true if the result of assignment STMT is know to be non-zero.
895 If the return value is based on the assumption that signed overflow is
896 undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't change
897 *STRICT_OVERFLOW_P.*/
900 gimple_assign_nonzero_warnv_p (gimple stmt
, bool *strict_overflow_p
)
902 enum tree_code code
= gimple_assign_rhs_code (stmt
);
903 switch (get_gimple_rhs_class (code
))
905 case GIMPLE_UNARY_RHS
:
906 return tree_unary_nonzero_warnv_p (gimple_assign_rhs_code (stmt
),
907 gimple_expr_type (stmt
),
908 gimple_assign_rhs1 (stmt
),
910 case GIMPLE_BINARY_RHS
:
911 return tree_binary_nonzero_warnv_p (gimple_assign_rhs_code (stmt
),
912 gimple_expr_type (stmt
),
913 gimple_assign_rhs1 (stmt
),
914 gimple_assign_rhs2 (stmt
),
916 case GIMPLE_SINGLE_RHS
:
917 return tree_single_nonzero_warnv_p (gimple_assign_rhs1 (stmt
),
919 case GIMPLE_INVALID_RHS
:
926 /* Return true if STMT is know to to compute a non-zero value.
927 If the return value is based on the assumption that signed overflow is
928 undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't change
929 *STRICT_OVERFLOW_P.*/
932 gimple_stmt_nonzero_warnv_p (gimple stmt
, bool *strict_overflow_p
)
934 switch (gimple_code (stmt
))
937 return gimple_assign_nonzero_warnv_p (stmt
, strict_overflow_p
);
939 return gimple_alloca_call_p (stmt
);
945 /* Like tree_expr_nonzero_warnv_p, but this function uses value ranges
949 vrp_stmt_computes_nonzero (gimple stmt
, bool *strict_overflow_p
)
951 if (gimple_stmt_nonzero_warnv_p (stmt
, strict_overflow_p
))
954 /* If we have an expression of the form &X->a, then the expression
955 is nonnull if X is nonnull. */
956 if (is_gimple_assign (stmt
)
957 && gimple_assign_rhs_code (stmt
) == ADDR_EXPR
)
959 tree expr
= gimple_assign_rhs1 (stmt
);
960 tree base
= get_base_address (TREE_OPERAND (expr
, 0));
962 if (base
!= NULL_TREE
963 && TREE_CODE (base
) == INDIRECT_REF
964 && TREE_CODE (TREE_OPERAND (base
, 0)) == SSA_NAME
)
966 value_range_t
*vr
= get_value_range (TREE_OPERAND (base
, 0));
967 if (range_is_nonnull (vr
))
975 /* Returns true if EXPR is a valid value (as expected by compare_values) --
976 a gimple invariant, or SSA_NAME +- CST. */
979 valid_value_p (tree expr
)
981 if (TREE_CODE (expr
) == SSA_NAME
)
984 if (TREE_CODE (expr
) == PLUS_EXPR
985 || TREE_CODE (expr
) == MINUS_EXPR
)
986 return (TREE_CODE (TREE_OPERAND (expr
, 0)) == SSA_NAME
987 && TREE_CODE (TREE_OPERAND (expr
, 1)) == INTEGER_CST
);
989 return is_gimple_min_invariant (expr
);
995 -2 if those are incomparable. */
997 operand_less_p (tree val
, tree val2
)
999 /* LT is folded faster than GE and others. Inline the common case. */
1000 if (TREE_CODE (val
) == INTEGER_CST
&& TREE_CODE (val2
) == INTEGER_CST
)
1002 if (TYPE_UNSIGNED (TREE_TYPE (val
)))
1003 return INT_CST_LT_UNSIGNED (val
, val2
);
1006 if (INT_CST_LT (val
, val2
))
1014 fold_defer_overflow_warnings ();
1016 tcmp
= fold_binary_to_constant (LT_EXPR
, boolean_type_node
, val
, val2
);
1018 fold_undefer_and_ignore_overflow_warnings ();
1021 || TREE_CODE (tcmp
) != INTEGER_CST
)
1024 if (!integer_zerop (tcmp
))
1028 /* val >= val2, not considering overflow infinity. */
1029 if (is_negative_overflow_infinity (val
))
1030 return is_negative_overflow_infinity (val2
) ? 0 : 1;
1031 else if (is_positive_overflow_infinity (val2
))
1032 return is_positive_overflow_infinity (val
) ? 0 : 1;
1037 /* Compare two values VAL1 and VAL2. Return
1039 -2 if VAL1 and VAL2 cannot be compared at compile-time,
1042 +1 if VAL1 > VAL2, and
1045 This is similar to tree_int_cst_compare but supports pointer values
1046 and values that cannot be compared at compile time.
1048 If STRICT_OVERFLOW_P is not NULL, then set *STRICT_OVERFLOW_P to
1049 true if the return value is only valid if we assume that signed
1050 overflow is undefined. */
1053 compare_values_warnv (tree val1
, tree val2
, bool *strict_overflow_p
)
1058 /* Below we rely on the fact that VAL1 and VAL2 are both pointers or
1060 gcc_assert (POINTER_TYPE_P (TREE_TYPE (val1
))
1061 == POINTER_TYPE_P (TREE_TYPE (val2
)));
1062 /* Convert the two values into the same type. This is needed because
1063 sizetype causes sign extension even for unsigned types. */
1064 val2
= fold_convert (TREE_TYPE (val1
), val2
);
1065 STRIP_USELESS_TYPE_CONVERSION (val2
);
1067 if ((TREE_CODE (val1
) == SSA_NAME
1068 || TREE_CODE (val1
) == PLUS_EXPR
1069 || TREE_CODE (val1
) == MINUS_EXPR
)
1070 && (TREE_CODE (val2
) == SSA_NAME
1071 || TREE_CODE (val2
) == PLUS_EXPR
1072 || TREE_CODE (val2
) == MINUS_EXPR
))
1074 tree n1
, c1
, n2
, c2
;
1075 enum tree_code code1
, code2
;
1077 /* If VAL1 and VAL2 are of the form 'NAME [+-] CST' or 'NAME',
1078 return -1 or +1 accordingly. If VAL1 and VAL2 don't use the
1079 same name, return -2. */
1080 if (TREE_CODE (val1
) == SSA_NAME
)
1088 code1
= TREE_CODE (val1
);
1089 n1
= TREE_OPERAND (val1
, 0);
1090 c1
= TREE_OPERAND (val1
, 1);
1091 if (tree_int_cst_sgn (c1
) == -1)
1093 if (is_negative_overflow_infinity (c1
))
1095 c1
= fold_unary_to_constant (NEGATE_EXPR
, TREE_TYPE (c1
), c1
);
1098 code1
= code1
== MINUS_EXPR
? PLUS_EXPR
: MINUS_EXPR
;
1102 if (TREE_CODE (val2
) == SSA_NAME
)
1110 code2
= TREE_CODE (val2
);
1111 n2
= TREE_OPERAND (val2
, 0);
1112 c2
= TREE_OPERAND (val2
, 1);
1113 if (tree_int_cst_sgn (c2
) == -1)
1115 if (is_negative_overflow_infinity (c2
))
1117 c2
= fold_unary_to_constant (NEGATE_EXPR
, TREE_TYPE (c2
), c2
);
1120 code2
= code2
== MINUS_EXPR
? PLUS_EXPR
: MINUS_EXPR
;
1124 /* Both values must use the same name. */
1128 if (code1
== SSA_NAME
1129 && code2
== SSA_NAME
)
1133 /* If overflow is defined we cannot simplify more. */
1134 if (!TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (val1
)))
1137 if (strict_overflow_p
!= NULL
1138 && (code1
== SSA_NAME
|| !TREE_NO_WARNING (val1
))
1139 && (code2
== SSA_NAME
|| !TREE_NO_WARNING (val2
)))
1140 *strict_overflow_p
= true;
1142 if (code1
== SSA_NAME
)
1144 if (code2
== PLUS_EXPR
)
1145 /* NAME < NAME + CST */
1147 else if (code2
== MINUS_EXPR
)
1148 /* NAME > NAME - CST */
1151 else if (code1
== PLUS_EXPR
)
1153 if (code2
== SSA_NAME
)
1154 /* NAME + CST > NAME */
1156 else if (code2
== PLUS_EXPR
)
1157 /* NAME + CST1 > NAME + CST2, if CST1 > CST2 */
1158 return compare_values_warnv (c1
, c2
, strict_overflow_p
);
1159 else if (code2
== MINUS_EXPR
)
1160 /* NAME + CST1 > NAME - CST2 */
1163 else if (code1
== MINUS_EXPR
)
1165 if (code2
== SSA_NAME
)
1166 /* NAME - CST < NAME */
1168 else if (code2
== PLUS_EXPR
)
1169 /* NAME - CST1 < NAME + CST2 */
1171 else if (code2
== MINUS_EXPR
)
1172 /* NAME - CST1 > NAME - CST2, if CST1 < CST2. Notice that
1173 C1 and C2 are swapped in the call to compare_values. */
1174 return compare_values_warnv (c2
, c1
, strict_overflow_p
);
1180 /* We cannot compare non-constants. */
1181 if (!is_gimple_min_invariant (val1
) || !is_gimple_min_invariant (val2
))
1184 if (!POINTER_TYPE_P (TREE_TYPE (val1
)))
1186 /* We cannot compare overflowed values, except for overflow
1188 if (TREE_OVERFLOW (val1
) || TREE_OVERFLOW (val2
))
1190 if (strict_overflow_p
!= NULL
)
1191 *strict_overflow_p
= true;
1192 if (is_negative_overflow_infinity (val1
))
1193 return is_negative_overflow_infinity (val2
) ? 0 : -1;
1194 else if (is_negative_overflow_infinity (val2
))
1196 else if (is_positive_overflow_infinity (val1
))
1197 return is_positive_overflow_infinity (val2
) ? 0 : 1;
1198 else if (is_positive_overflow_infinity (val2
))
1203 return tree_int_cst_compare (val1
, val2
);
1209 /* First see if VAL1 and VAL2 are not the same. */
1210 if (val1
== val2
|| operand_equal_p (val1
, val2
, 0))
1213 /* If VAL1 is a lower address than VAL2, return -1. */
1214 if (operand_less_p (val1
, val2
) == 1)
1217 /* If VAL1 is a higher address than VAL2, return +1. */
1218 if (operand_less_p (val2
, val1
) == 1)
1221 /* If VAL1 is different than VAL2, return +2.
1222 For integer constants we either have already returned -1 or 1
1223 or they are equivalent. We still might succeed in proving
1224 something about non-trivial operands. */
1225 if (TREE_CODE (val1
) != INTEGER_CST
1226 || TREE_CODE (val2
) != INTEGER_CST
)
1228 t
= fold_binary_to_constant (NE_EXPR
, boolean_type_node
, val1
, val2
);
1229 if (t
&& integer_onep (t
))
1237 /* Compare values like compare_values_warnv, but treat comparisons of
1238 nonconstants which rely on undefined overflow as incomparable. */
1241 compare_values (tree val1
, tree val2
)
1247 ret
= compare_values_warnv (val1
, val2
, &sop
);
1249 && (!is_gimple_min_invariant (val1
) || !is_gimple_min_invariant (val2
)))
1255 /* Return 1 if VAL is inside value range VR (VR->MIN <= VAL <= VR->MAX),
1256 0 if VAL is not inside VR,
1257 -2 if we cannot tell either way.
1259 FIXME, the current semantics of this functions are a bit quirky
1260 when taken in the context of VRP. In here we do not care
1261 about VR's type. If VR is the anti-range ~[3, 5] the call
1262 value_inside_range (4, VR) will return 1.
1264 This is counter-intuitive in a strict sense, but the callers
1265 currently expect this. They are calling the function
1266 merely to determine whether VR->MIN <= VAL <= VR->MAX. The
1267 callers are applying the VR_RANGE/VR_ANTI_RANGE semantics
1270 This also applies to value_ranges_intersect_p and
1271 range_includes_zero_p. The semantics of VR_RANGE and
1272 VR_ANTI_RANGE should be encoded here, but that also means
1273 adapting the users of these functions to the new semantics.
1275 Benchmark compile/20001226-1.c compilation time after changing this
1279 value_inside_range (tree val
, value_range_t
* vr
)
1283 cmp1
= operand_less_p (val
, vr
->min
);
1289 cmp2
= operand_less_p (vr
->max
, val
);
1297 /* Return true if value ranges VR0 and VR1 have a non-empty
1300 Benchmark compile/20001226-1.c compilation time after changing this
1305 value_ranges_intersect_p (value_range_t
*vr0
, value_range_t
*vr1
)
1307 /* The value ranges do not intersect if the maximum of the first range is
1308 less than the minimum of the second range or vice versa.
1309 When those relations are unknown, we can't do any better. */
1310 if (operand_less_p (vr0
->max
, vr1
->min
) != 0)
1312 if (operand_less_p (vr1
->max
, vr0
->min
) != 0)
1318 /* Return true if VR includes the value zero, false otherwise. FIXME,
1319 currently this will return false for an anti-range like ~[-4, 3].
1320 This will be wrong when the semantics of value_inside_range are
1321 modified (currently the users of this function expect these
1325 range_includes_zero_p (value_range_t
*vr
)
1329 gcc_assert (vr
->type
!= VR_UNDEFINED
1330 && vr
->type
!= VR_VARYING
1331 && !symbolic_range_p (vr
));
1333 zero
= build_int_cst (TREE_TYPE (vr
->min
), 0);
1334 return (value_inside_range (zero
, vr
) == 1);
1337 /* Return true if T, an SSA_NAME, is known to be nonnegative. Return
1338 false otherwise or if no value range information is available. */
1341 ssa_name_nonnegative_p (const_tree t
)
1343 value_range_t
*vr
= get_value_range (t
);
1348 /* Testing for VR_ANTI_RANGE is not useful here as any anti-range
1349 which would return a useful value should be encoded as a VR_RANGE. */
1350 if (vr
->type
== VR_RANGE
)
1352 int result
= compare_values (vr
->min
, integer_zero_node
);
1354 return (result
== 0 || result
== 1);
1359 /* If OP has a value range with a single constant value return that,
1360 otherwise return NULL_TREE. This returns OP itself if OP is a
1364 op_with_constant_singleton_value_range (tree op
)
1368 if (is_gimple_min_invariant (op
))
1371 if (TREE_CODE (op
) != SSA_NAME
)
1374 vr
= get_value_range (op
);
1375 if (vr
->type
== VR_RANGE
1376 && operand_equal_p (vr
->min
, vr
->max
, 0)
1377 && is_gimple_min_invariant (vr
->min
))
1384 /* Extract value range information from an ASSERT_EXPR EXPR and store
1388 extract_range_from_assert (value_range_t
*vr_p
, tree expr
)
1390 tree var
, cond
, limit
, min
, max
, type
;
1391 value_range_t
*var_vr
, *limit_vr
;
1392 enum tree_code cond_code
;
1394 var
= ASSERT_EXPR_VAR (expr
);
1395 cond
= ASSERT_EXPR_COND (expr
);
1397 gcc_assert (COMPARISON_CLASS_P (cond
));
1399 /* Find VAR in the ASSERT_EXPR conditional. */
1400 if (var
== TREE_OPERAND (cond
, 0)
1401 || TREE_CODE (TREE_OPERAND (cond
, 0)) == PLUS_EXPR
1402 || TREE_CODE (TREE_OPERAND (cond
, 0)) == NOP_EXPR
)
1404 /* If the predicate is of the form VAR COMP LIMIT, then we just
1405 take LIMIT from the RHS and use the same comparison code. */
1406 cond_code
= TREE_CODE (cond
);
1407 limit
= TREE_OPERAND (cond
, 1);
1408 cond
= TREE_OPERAND (cond
, 0);
1412 /* If the predicate is of the form LIMIT COMP VAR, then we need
1413 to flip around the comparison code to create the proper range
1415 cond_code
= swap_tree_comparison (TREE_CODE (cond
));
1416 limit
= TREE_OPERAND (cond
, 0);
1417 cond
= TREE_OPERAND (cond
, 1);
1420 limit
= avoid_overflow_infinity (limit
);
1422 type
= TREE_TYPE (limit
);
1423 gcc_assert (limit
!= var
);
1425 /* For pointer arithmetic, we only keep track of pointer equality
1427 if (POINTER_TYPE_P (type
) && cond_code
!= NE_EXPR
&& cond_code
!= EQ_EXPR
)
1429 set_value_range_to_varying (vr_p
);
1433 /* If LIMIT is another SSA name and LIMIT has a range of its own,
1434 try to use LIMIT's range to avoid creating symbolic ranges
1436 limit_vr
= (TREE_CODE (limit
) == SSA_NAME
) ? get_value_range (limit
) : NULL
;
1438 /* LIMIT's range is only interesting if it has any useful information. */
1440 && (limit_vr
->type
== VR_UNDEFINED
1441 || limit_vr
->type
== VR_VARYING
1442 || symbolic_range_p (limit_vr
)))
1445 /* Initially, the new range has the same set of equivalences of
1446 VAR's range. This will be revised before returning the final
1447 value. Since assertions may be chained via mutually exclusive
1448 predicates, we will need to trim the set of equivalences before
1450 gcc_assert (vr_p
->equiv
== NULL
);
1451 add_equivalence (&vr_p
->equiv
, var
);
1453 /* Extract a new range based on the asserted comparison for VAR and
1454 LIMIT's value range. Notice that if LIMIT has an anti-range, we
1455 will only use it for equality comparisons (EQ_EXPR). For any
1456 other kind of assertion, we cannot derive a range from LIMIT's
1457 anti-range that can be used to describe the new range. For
1458 instance, ASSERT_EXPR <x_2, x_2 <= b_4>. If b_4 is ~[2, 10],
1459 then b_4 takes on the ranges [-INF, 1] and [11, +INF]. There is
1460 no single range for x_2 that could describe LE_EXPR, so we might
1461 as well build the range [b_4, +INF] for it.
1462 One special case we handle is extracting a range from a
1463 range test encoded as (unsigned)var + CST <= limit. */
1464 if (TREE_CODE (cond
) == NOP_EXPR
1465 || TREE_CODE (cond
) == PLUS_EXPR
)
1467 if (TREE_CODE (cond
) == PLUS_EXPR
)
1469 min
= fold_build1 (NEGATE_EXPR
, TREE_TYPE (TREE_OPERAND (cond
, 1)),
1470 TREE_OPERAND (cond
, 1));
1471 max
= int_const_binop (PLUS_EXPR
, limit
, min
, 0);
1472 cond
= TREE_OPERAND (cond
, 0);
1476 min
= build_int_cst (TREE_TYPE (var
), 0);
1480 /* Make sure to not set TREE_OVERFLOW on the final type
1481 conversion. We are willingly interpreting large positive
1482 unsigned values as negative singed values here. */
1483 min
= force_fit_type_double (TREE_TYPE (var
), TREE_INT_CST_LOW (min
),
1484 TREE_INT_CST_HIGH (min
), 0, false);
1485 max
= force_fit_type_double (TREE_TYPE (var
), TREE_INT_CST_LOW (max
),
1486 TREE_INT_CST_HIGH (max
), 0, false);
1488 /* We can transform a max, min range to an anti-range or
1489 vice-versa. Use set_and_canonicalize_value_range which does
1491 if (cond_code
== LE_EXPR
)
1492 set_and_canonicalize_value_range (vr_p
, VR_RANGE
,
1493 min
, max
, vr_p
->equiv
);
1494 else if (cond_code
== GT_EXPR
)
1495 set_and_canonicalize_value_range (vr_p
, VR_ANTI_RANGE
,
1496 min
, max
, vr_p
->equiv
);
1500 else if (cond_code
== EQ_EXPR
)
1502 enum value_range_type range_type
;
1506 range_type
= limit_vr
->type
;
1507 min
= limit_vr
->min
;
1508 max
= limit_vr
->max
;
1512 range_type
= VR_RANGE
;
1517 set_value_range (vr_p
, range_type
, min
, max
, vr_p
->equiv
);
1519 /* When asserting the equality VAR == LIMIT and LIMIT is another
1520 SSA name, the new range will also inherit the equivalence set
1522 if (TREE_CODE (limit
) == SSA_NAME
)
1523 add_equivalence (&vr_p
->equiv
, limit
);
1525 else if (cond_code
== NE_EXPR
)
1527 /* As described above, when LIMIT's range is an anti-range and
1528 this assertion is an inequality (NE_EXPR), then we cannot
1529 derive anything from the anti-range. For instance, if
1530 LIMIT's range was ~[0, 0], the assertion 'VAR != LIMIT' does
1531 not imply that VAR's range is [0, 0]. So, in the case of
1532 anti-ranges, we just assert the inequality using LIMIT and
1535 If LIMIT_VR is a range, we can only use it to build a new
1536 anti-range if LIMIT_VR is a single-valued range. For
1537 instance, if LIMIT_VR is [0, 1], the predicate
1538 VAR != [0, 1] does not mean that VAR's range is ~[0, 1].
1539 Rather, it means that for value 0 VAR should be ~[0, 0]
1540 and for value 1, VAR should be ~[1, 1]. We cannot
1541 represent these ranges.
1543 The only situation in which we can build a valid
1544 anti-range is when LIMIT_VR is a single-valued range
1545 (i.e., LIMIT_VR->MIN == LIMIT_VR->MAX). In that case,
1546 build the anti-range ~[LIMIT_VR->MIN, LIMIT_VR->MAX]. */
1548 && limit_vr
->type
== VR_RANGE
1549 && compare_values (limit_vr
->min
, limit_vr
->max
) == 0)
1551 min
= limit_vr
->min
;
1552 max
= limit_vr
->max
;
1556 /* In any other case, we cannot use LIMIT's range to build a
1557 valid anti-range. */
1561 /* If MIN and MAX cover the whole range for their type, then
1562 just use the original LIMIT. */
1563 if (INTEGRAL_TYPE_P (type
)
1564 && vrp_val_is_min (min
)
1565 && vrp_val_is_max (max
))
1568 set_value_range (vr_p
, VR_ANTI_RANGE
, min
, max
, vr_p
->equiv
);
1570 else if (cond_code
== LE_EXPR
|| cond_code
== LT_EXPR
)
1572 min
= TYPE_MIN_VALUE (type
);
1574 if (limit_vr
== NULL
|| limit_vr
->type
== VR_ANTI_RANGE
)
1578 /* If LIMIT_VR is of the form [N1, N2], we need to build the
1579 range [MIN, N2] for LE_EXPR and [MIN, N2 - 1] for
1581 max
= limit_vr
->max
;
1584 /* If the maximum value forces us to be out of bounds, simply punt.
1585 It would be pointless to try and do anything more since this
1586 all should be optimized away above us. */
1587 if ((cond_code
== LT_EXPR
1588 && compare_values (max
, min
) == 0)
1589 || (CONSTANT_CLASS_P (max
) && TREE_OVERFLOW (max
)))
1590 set_value_range_to_varying (vr_p
);
1593 /* For LT_EXPR, we create the range [MIN, MAX - 1]. */
1594 if (cond_code
== LT_EXPR
)
1596 tree one
= build_int_cst (type
, 1);
1597 max
= fold_build2 (MINUS_EXPR
, type
, max
, one
);
1599 TREE_NO_WARNING (max
) = 1;
1602 set_value_range (vr_p
, VR_RANGE
, min
, max
, vr_p
->equiv
);
1605 else if (cond_code
== GE_EXPR
|| cond_code
== GT_EXPR
)
1607 max
= TYPE_MAX_VALUE (type
);
1609 if (limit_vr
== NULL
|| limit_vr
->type
== VR_ANTI_RANGE
)
1613 /* If LIMIT_VR is of the form [N1, N2], we need to build the
1614 range [N1, MAX] for GE_EXPR and [N1 + 1, MAX] for
1616 min
= limit_vr
->min
;
1619 /* If the minimum value forces us to be out of bounds, simply punt.
1620 It would be pointless to try and do anything more since this
1621 all should be optimized away above us. */
1622 if ((cond_code
== GT_EXPR
1623 && compare_values (min
, max
) == 0)
1624 || (CONSTANT_CLASS_P (min
) && TREE_OVERFLOW (min
)))
1625 set_value_range_to_varying (vr_p
);
1628 /* For GT_EXPR, we create the range [MIN + 1, MAX]. */
1629 if (cond_code
== GT_EXPR
)
1631 tree one
= build_int_cst (type
, 1);
1632 min
= fold_build2 (PLUS_EXPR
, type
, min
, one
);
1634 TREE_NO_WARNING (min
) = 1;
1637 set_value_range (vr_p
, VR_RANGE
, min
, max
, vr_p
->equiv
);
1643 /* If VAR already had a known range, it may happen that the new
1644 range we have computed and VAR's range are not compatible. For
1648 p_6 = ASSERT_EXPR <p_5, p_5 == NULL>;
1650 p_8 = ASSERT_EXPR <p_6, p_6 != NULL>;
1652 While the above comes from a faulty program, it will cause an ICE
1653 later because p_8 and p_6 will have incompatible ranges and at
1654 the same time will be considered equivalent. A similar situation
1658 i_6 = ASSERT_EXPR <i_5, i_5 > 10>;
1660 i_7 = ASSERT_EXPR <i_6, i_6 < 5>;
1662 Again i_6 and i_7 will have incompatible ranges. It would be
1663 pointless to try and do anything with i_7's range because
1664 anything dominated by 'if (i_5 < 5)' will be optimized away.
1665 Note, due to the wa in which simulation proceeds, the statement
1666 i_7 = ASSERT_EXPR <...> we would never be visited because the
1667 conditional 'if (i_5 < 5)' always evaluates to false. However,
1668 this extra check does not hurt and may protect against future
1669 changes to VRP that may get into a situation similar to the
1670 NULL pointer dereference example.
1672 Note that these compatibility tests are only needed when dealing
1673 with ranges or a mix of range and anti-range. If VAR_VR and VR_P
1674 are both anti-ranges, they will always be compatible, because two
1675 anti-ranges will always have a non-empty intersection. */
1677 var_vr
= get_value_range (var
);
1679 /* We may need to make adjustments when VR_P and VAR_VR are numeric
1680 ranges or anti-ranges. */
1681 if (vr_p
->type
== VR_VARYING
1682 || vr_p
->type
== VR_UNDEFINED
1683 || var_vr
->type
== VR_VARYING
1684 || var_vr
->type
== VR_UNDEFINED
1685 || symbolic_range_p (vr_p
)
1686 || symbolic_range_p (var_vr
))
1689 if (var_vr
->type
== VR_RANGE
&& vr_p
->type
== VR_RANGE
)
1691 /* If the two ranges have a non-empty intersection, we can
1692 refine the resulting range. Since the assert expression
1693 creates an equivalency and at the same time it asserts a
1694 predicate, we can take the intersection of the two ranges to
1695 get better precision. */
1696 if (value_ranges_intersect_p (var_vr
, vr_p
))
1698 /* Use the larger of the two minimums. */
1699 if (compare_values (vr_p
->min
, var_vr
->min
) == -1)
1704 /* Use the smaller of the two maximums. */
1705 if (compare_values (vr_p
->max
, var_vr
->max
) == 1)
1710 set_value_range (vr_p
, vr_p
->type
, min
, max
, vr_p
->equiv
);
1714 /* The two ranges do not intersect, set the new range to
1715 VARYING, because we will not be able to do anything
1716 meaningful with it. */
1717 set_value_range_to_varying (vr_p
);
1720 else if ((var_vr
->type
== VR_RANGE
&& vr_p
->type
== VR_ANTI_RANGE
)
1721 || (var_vr
->type
== VR_ANTI_RANGE
&& vr_p
->type
== VR_RANGE
))
1723 /* A range and an anti-range will cancel each other only if
1724 their ends are the same. For instance, in the example above,
1725 p_8's range ~[0, 0] and p_6's range [0, 0] are incompatible,
1726 so VR_P should be set to VR_VARYING. */
1727 if (compare_values (var_vr
->min
, vr_p
->min
) == 0
1728 && compare_values (var_vr
->max
, vr_p
->max
) == 0)
1729 set_value_range_to_varying (vr_p
);
1732 tree min
, max
, anti_min
, anti_max
, real_min
, real_max
;
1735 /* We want to compute the logical AND of the two ranges;
1736 there are three cases to consider.
1739 1. The VR_ANTI_RANGE range is completely within the
1740 VR_RANGE and the endpoints of the ranges are
1741 different. In that case the resulting range
1742 should be whichever range is more precise.
1743 Typically that will be the VR_RANGE.
1745 2. The VR_ANTI_RANGE is completely disjoint from
1746 the VR_RANGE. In this case the resulting range
1747 should be the VR_RANGE.
1749 3. There is some overlap between the VR_ANTI_RANGE
1752 3a. If the high limit of the VR_ANTI_RANGE resides
1753 within the VR_RANGE, then the result is a new
1754 VR_RANGE starting at the high limit of the
1755 VR_ANTI_RANGE + 1 and extending to the
1756 high limit of the original VR_RANGE.
1758 3b. If the low limit of the VR_ANTI_RANGE resides
1759 within the VR_RANGE, then the result is a new
1760 VR_RANGE starting at the low limit of the original
1761 VR_RANGE and extending to the low limit of the
1762 VR_ANTI_RANGE - 1. */
1763 if (vr_p
->type
== VR_ANTI_RANGE
)
1765 anti_min
= vr_p
->min
;
1766 anti_max
= vr_p
->max
;
1767 real_min
= var_vr
->min
;
1768 real_max
= var_vr
->max
;
1772 anti_min
= var_vr
->min
;
1773 anti_max
= var_vr
->max
;
1774 real_min
= vr_p
->min
;
1775 real_max
= vr_p
->max
;
1779 /* Case 1, VR_ANTI_RANGE completely within VR_RANGE,
1780 not including any endpoints. */
1781 if (compare_values (anti_max
, real_max
) == -1
1782 && compare_values (anti_min
, real_min
) == 1)
1784 /* If the range is covering the whole valid range of
1785 the type keep the anti-range. */
1786 if (!vrp_val_is_min (real_min
)
1787 || !vrp_val_is_max (real_max
))
1788 set_value_range (vr_p
, VR_RANGE
, real_min
,
1789 real_max
, vr_p
->equiv
);
1791 /* Case 2, VR_ANTI_RANGE completely disjoint from
1793 else if (compare_values (anti_min
, real_max
) == 1
1794 || compare_values (anti_max
, real_min
) == -1)
1796 set_value_range (vr_p
, VR_RANGE
, real_min
,
1797 real_max
, vr_p
->equiv
);
1799 /* Case 3a, the anti-range extends into the low
1800 part of the real range. Thus creating a new
1801 low for the real range. */
1802 else if (((cmp
= compare_values (anti_max
, real_min
)) == 1
1804 && compare_values (anti_max
, real_max
) == -1)
1806 gcc_assert (!is_positive_overflow_infinity (anti_max
));
1807 if (needs_overflow_infinity (TREE_TYPE (anti_max
))
1808 && vrp_val_is_max (anti_max
))
1810 if (!supports_overflow_infinity (TREE_TYPE (var_vr
->min
)))
1812 set_value_range_to_varying (vr_p
);
1815 min
= positive_overflow_infinity (TREE_TYPE (var_vr
->min
));
1817 else if (!POINTER_TYPE_P (TREE_TYPE (var_vr
->min
)))
1818 min
= fold_build2 (PLUS_EXPR
, TREE_TYPE (var_vr
->min
),
1820 build_int_cst (TREE_TYPE (var_vr
->min
), 1));
1822 min
= fold_build2 (POINTER_PLUS_EXPR
, TREE_TYPE (var_vr
->min
),
1823 anti_max
, size_int (1));
1825 set_value_range (vr_p
, VR_RANGE
, min
, max
, vr_p
->equiv
);
1827 /* Case 3b, the anti-range extends into the high
1828 part of the real range. Thus creating a new
1829 higher for the real range. */
1830 else if (compare_values (anti_min
, real_min
) == 1
1831 && ((cmp
= compare_values (anti_min
, real_max
)) == -1
1834 gcc_assert (!is_negative_overflow_infinity (anti_min
));
1835 if (needs_overflow_infinity (TREE_TYPE (anti_min
))
1836 && vrp_val_is_min (anti_min
))
1838 if (!supports_overflow_infinity (TREE_TYPE (var_vr
->min
)))
1840 set_value_range_to_varying (vr_p
);
1843 max
= negative_overflow_infinity (TREE_TYPE (var_vr
->min
));
1845 else if (!POINTER_TYPE_P (TREE_TYPE (var_vr
->min
)))
1846 max
= fold_build2 (MINUS_EXPR
, TREE_TYPE (var_vr
->min
),
1848 build_int_cst (TREE_TYPE (var_vr
->min
), 1));
1850 max
= fold_build2 (POINTER_PLUS_EXPR
, TREE_TYPE (var_vr
->min
),
1854 set_value_range (vr_p
, VR_RANGE
, min
, max
, vr_p
->equiv
);
1861 /* Extract range information from SSA name VAR and store it in VR. If
1862 VAR has an interesting range, use it. Otherwise, create the
1863 range [VAR, VAR] and return it. This is useful in situations where
1864 we may have conditionals testing values of VARYING names. For
1871 Even if y_5 is deemed VARYING, we can determine that x_3 > y_5 is
1875 extract_range_from_ssa_name (value_range_t
*vr
, tree var
)
1877 value_range_t
*var_vr
= get_value_range (var
);
1879 if (var_vr
->type
!= VR_UNDEFINED
&& var_vr
->type
!= VR_VARYING
)
1880 copy_value_range (vr
, var_vr
);
1882 set_value_range (vr
, VR_RANGE
, var
, var
, NULL
);
1884 add_equivalence (&vr
->equiv
, var
);
1888 /* Wrapper around int_const_binop. If the operation overflows and we
1889 are not using wrapping arithmetic, then adjust the result to be
1890 -INF or +INF depending on CODE, VAL1 and VAL2. This can return
1891 NULL_TREE if we need to use an overflow infinity representation but
1892 the type does not support it. */
1895 vrp_int_const_binop (enum tree_code code
, tree val1
, tree val2
)
1899 res
= int_const_binop (code
, val1
, val2
, 0);
1901 /* If we are not using wrapping arithmetic, operate symbolically
1902 on -INF and +INF. */
1903 if (TYPE_OVERFLOW_WRAPS (TREE_TYPE (val1
)))
1905 int checkz
= compare_values (res
, val1
);
1906 bool overflow
= false;
1908 /* Ensure that res = val1 [+*] val2 >= val1
1909 or that res = val1 - val2 <= val1. */
1910 if ((code
== PLUS_EXPR
1911 && !(checkz
== 1 || checkz
== 0))
1912 || (code
== MINUS_EXPR
1913 && !(checkz
== 0 || checkz
== -1)))
1917 /* Checking for multiplication overflow is done by dividing the
1918 output of the multiplication by the first input of the
1919 multiplication. If the result of that division operation is
1920 not equal to the second input of the multiplication, then the
1921 multiplication overflowed. */
1922 else if (code
== MULT_EXPR
&& !integer_zerop (val1
))
1924 tree tmp
= int_const_binop (TRUNC_DIV_EXPR
,
1927 int check
= compare_values (tmp
, val2
);
1935 res
= copy_node (res
);
1936 TREE_OVERFLOW (res
) = 1;
1940 else if ((TREE_OVERFLOW (res
)
1941 && !TREE_OVERFLOW (val1
)
1942 && !TREE_OVERFLOW (val2
))
1943 || is_overflow_infinity (val1
)
1944 || is_overflow_infinity (val2
))
1946 /* If the operation overflowed but neither VAL1 nor VAL2 are
1947 overflown, return -INF or +INF depending on the operation
1948 and the combination of signs of the operands. */
1949 int sgn1
= tree_int_cst_sgn (val1
);
1950 int sgn2
= tree_int_cst_sgn (val2
);
1952 if (needs_overflow_infinity (TREE_TYPE (res
))
1953 && !supports_overflow_infinity (TREE_TYPE (res
)))
1956 /* We have to punt on adding infinities of different signs,
1957 since we can't tell what the sign of the result should be.
1958 Likewise for subtracting infinities of the same sign. */
1959 if (((code
== PLUS_EXPR
&& sgn1
!= sgn2
)
1960 || (code
== MINUS_EXPR
&& sgn1
== sgn2
))
1961 && is_overflow_infinity (val1
)
1962 && is_overflow_infinity (val2
))
1965 /* Don't try to handle division or shifting of infinities. */
1966 if ((code
== TRUNC_DIV_EXPR
1967 || code
== FLOOR_DIV_EXPR
1968 || code
== CEIL_DIV_EXPR
1969 || code
== EXACT_DIV_EXPR
1970 || code
== ROUND_DIV_EXPR
1971 || code
== RSHIFT_EXPR
)
1972 && (is_overflow_infinity (val1
)
1973 || is_overflow_infinity (val2
)))
1976 /* Notice that we only need to handle the restricted set of
1977 operations handled by extract_range_from_binary_expr.
1978 Among them, only multiplication, addition and subtraction
1979 can yield overflow without overflown operands because we
1980 are working with integral types only... except in the
1981 case VAL1 = -INF and VAL2 = -1 which overflows to +INF
1982 for division too. */
1984 /* For multiplication, the sign of the overflow is given
1985 by the comparison of the signs of the operands. */
1986 if ((code
== MULT_EXPR
&& sgn1
== sgn2
)
1987 /* For addition, the operands must be of the same sign
1988 to yield an overflow. Its sign is therefore that
1989 of one of the operands, for example the first. For
1990 infinite operands X + -INF is negative, not positive. */
1991 || (code
== PLUS_EXPR
1993 ? !is_negative_overflow_infinity (val2
)
1994 : is_positive_overflow_infinity (val2
)))
1995 /* For subtraction, non-infinite operands must be of
1996 different signs to yield an overflow. Its sign is
1997 therefore that of the first operand or the opposite of
1998 that of the second operand. A first operand of 0 counts
1999 as positive here, for the corner case 0 - (-INF), which
2000 overflows, but must yield +INF. For infinite operands 0
2001 - INF is negative, not positive. */
2002 || (code
== MINUS_EXPR
2004 ? !is_positive_overflow_infinity (val2
)
2005 : is_negative_overflow_infinity (val2
)))
2006 /* We only get in here with positive shift count, so the
2007 overflow direction is the same as the sign of val1.
2008 Actually rshift does not overflow at all, but we only
2009 handle the case of shifting overflowed -INF and +INF. */
2010 || (code
== RSHIFT_EXPR
2012 /* For division, the only case is -INF / -1 = +INF. */
2013 || code
== TRUNC_DIV_EXPR
2014 || code
== FLOOR_DIV_EXPR
2015 || code
== CEIL_DIV_EXPR
2016 || code
== EXACT_DIV_EXPR
2017 || code
== ROUND_DIV_EXPR
)
2018 return (needs_overflow_infinity (TREE_TYPE (res
))
2019 ? positive_overflow_infinity (TREE_TYPE (res
))
2020 : TYPE_MAX_VALUE (TREE_TYPE (res
)));
2022 return (needs_overflow_infinity (TREE_TYPE (res
))
2023 ? negative_overflow_infinity (TREE_TYPE (res
))
2024 : TYPE_MIN_VALUE (TREE_TYPE (res
)));
2031 /* Extract range information from a binary expression EXPR based on
2032 the ranges of each of its operands and the expression code. */
2035 extract_range_from_binary_expr (value_range_t
*vr
,
2036 enum tree_code code
,
2037 tree expr_type
, tree op0
, tree op1
)
2039 enum value_range_type type
;
2042 value_range_t vr0
= { VR_UNDEFINED
, NULL_TREE
, NULL_TREE
, NULL
};
2043 value_range_t vr1
= { VR_UNDEFINED
, NULL_TREE
, NULL_TREE
, NULL
};
2045 /* Not all binary expressions can be applied to ranges in a
2046 meaningful way. Handle only arithmetic operations. */
2047 if (code
!= PLUS_EXPR
2048 && code
!= MINUS_EXPR
2049 && code
!= POINTER_PLUS_EXPR
2050 && code
!= MULT_EXPR
2051 && code
!= TRUNC_DIV_EXPR
2052 && code
!= FLOOR_DIV_EXPR
2053 && code
!= CEIL_DIV_EXPR
2054 && code
!= EXACT_DIV_EXPR
2055 && code
!= ROUND_DIV_EXPR
2056 && code
!= RSHIFT_EXPR
2059 && code
!= BIT_AND_EXPR
2060 && code
!= BIT_IOR_EXPR
2061 && code
!= TRUTH_AND_EXPR
2062 && code
!= TRUTH_OR_EXPR
)
2064 /* We can still do constant propagation here. */
2065 tree const_op0
= op_with_constant_singleton_value_range (op0
);
2066 tree const_op1
= op_with_constant_singleton_value_range (op1
);
2067 if (const_op0
|| const_op1
)
2069 tree tem
= fold_binary (code
, expr_type
,
2070 const_op0
? const_op0
: op0
,
2071 const_op1
? const_op1
: op1
);
2073 && is_gimple_min_invariant (tem
)
2074 && !is_overflow_infinity (tem
))
2076 set_value_range (vr
, VR_RANGE
, tem
, tem
, NULL
);
2080 set_value_range_to_varying (vr
);
2084 /* Get value ranges for each operand. For constant operands, create
2085 a new value range with the operand to simplify processing. */
2086 if (TREE_CODE (op0
) == SSA_NAME
)
2087 vr0
= *(get_value_range (op0
));
2088 else if (is_gimple_min_invariant (op0
))
2089 set_value_range_to_value (&vr0
, op0
, NULL
);
2091 set_value_range_to_varying (&vr0
);
2093 if (TREE_CODE (op1
) == SSA_NAME
)
2094 vr1
= *(get_value_range (op1
));
2095 else if (is_gimple_min_invariant (op1
))
2096 set_value_range_to_value (&vr1
, op1
, NULL
);
2098 set_value_range_to_varying (&vr1
);
2100 /* If either range is UNDEFINED, so is the result. */
2101 if (vr0
.type
== VR_UNDEFINED
|| vr1
.type
== VR_UNDEFINED
)
2103 set_value_range_to_undefined (vr
);
2107 /* The type of the resulting value range defaults to VR0.TYPE. */
2110 /* Refuse to operate on VARYING ranges, ranges of different kinds
2111 and symbolic ranges. As an exception, we allow BIT_AND_EXPR
2112 because we may be able to derive a useful range even if one of
2113 the operands is VR_VARYING or symbolic range. Similarly for
2114 divisions. TODO, we may be able to derive anti-ranges in
2116 if (code
!= BIT_AND_EXPR
2117 && code
!= TRUTH_AND_EXPR
2118 && code
!= TRUTH_OR_EXPR
2119 && code
!= TRUNC_DIV_EXPR
2120 && code
!= FLOOR_DIV_EXPR
2121 && code
!= CEIL_DIV_EXPR
2122 && code
!= EXACT_DIV_EXPR
2123 && code
!= ROUND_DIV_EXPR
2124 && (vr0
.type
== VR_VARYING
2125 || vr1
.type
== VR_VARYING
2126 || vr0
.type
!= vr1
.type
2127 || symbolic_range_p (&vr0
)
2128 || symbolic_range_p (&vr1
)))
2130 set_value_range_to_varying (vr
);
2134 /* Now evaluate the expression to determine the new range. */
2135 if (POINTER_TYPE_P (expr_type
)
2136 || POINTER_TYPE_P (TREE_TYPE (op0
))
2137 || POINTER_TYPE_P (TREE_TYPE (op1
)))
2139 if (code
== MIN_EXPR
|| code
== MAX_EXPR
)
2141 /* For MIN/MAX expressions with pointers, we only care about
2142 nullness, if both are non null, then the result is nonnull.
2143 If both are null, then the result is null. Otherwise they
2145 if (range_is_nonnull (&vr0
) && range_is_nonnull (&vr1
))
2146 set_value_range_to_nonnull (vr
, expr_type
);
2147 else if (range_is_null (&vr0
) && range_is_null (&vr1
))
2148 set_value_range_to_null (vr
, expr_type
);
2150 set_value_range_to_varying (vr
);
2154 gcc_assert (code
== POINTER_PLUS_EXPR
);
2155 /* For pointer types, we are really only interested in asserting
2156 whether the expression evaluates to non-NULL. */
2157 if (range_is_nonnull (&vr0
) || range_is_nonnull (&vr1
))
2158 set_value_range_to_nonnull (vr
, expr_type
);
2159 else if (range_is_null (&vr0
) && range_is_null (&vr1
))
2160 set_value_range_to_null (vr
, expr_type
);
2162 set_value_range_to_varying (vr
);
2167 /* For integer ranges, apply the operation to each end of the
2168 range and see what we end up with. */
2169 if (code
== TRUTH_AND_EXPR
2170 || code
== TRUTH_OR_EXPR
)
2172 /* If one of the operands is zero, we know that the whole
2173 expression evaluates zero. */
2174 if (code
== TRUTH_AND_EXPR
2175 && ((vr0
.type
== VR_RANGE
2176 && integer_zerop (vr0
.min
)
2177 && integer_zerop (vr0
.max
))
2178 || (vr1
.type
== VR_RANGE
2179 && integer_zerop (vr1
.min
)
2180 && integer_zerop (vr1
.max
))))
2183 min
= max
= build_int_cst (expr_type
, 0);
2185 /* If one of the operands is one, we know that the whole
2186 expression evaluates one. */
2187 else if (code
== TRUTH_OR_EXPR
2188 && ((vr0
.type
== VR_RANGE
2189 && integer_onep (vr0
.min
)
2190 && integer_onep (vr0
.max
))
2191 || (vr1
.type
== VR_RANGE
2192 && integer_onep (vr1
.min
)
2193 && integer_onep (vr1
.max
))))
2196 min
= max
= build_int_cst (expr_type
, 1);
2198 else if (vr0
.type
!= VR_VARYING
2199 && vr1
.type
!= VR_VARYING
2200 && vr0
.type
== vr1
.type
2201 && !symbolic_range_p (&vr0
)
2202 && !overflow_infinity_range_p (&vr0
)
2203 && !symbolic_range_p (&vr1
)
2204 && !overflow_infinity_range_p (&vr1
))
2206 /* Boolean expressions cannot be folded with int_const_binop. */
2207 min
= fold_binary (code
, expr_type
, vr0
.min
, vr1
.min
);
2208 max
= fold_binary (code
, expr_type
, vr0
.max
, vr1
.max
);
2212 /* The result of a TRUTH_*_EXPR is always true or false. */
2213 set_value_range_to_truthvalue (vr
, expr_type
);
2217 else if (code
== PLUS_EXPR
2219 || code
== MAX_EXPR
)
2221 /* If we have a PLUS_EXPR with two VR_ANTI_RANGEs, drop to
2222 VR_VARYING. It would take more effort to compute a precise
2223 range for such a case. For example, if we have op0 == 1 and
2224 op1 == -1 with their ranges both being ~[0,0], we would have
2225 op0 + op1 == 0, so we cannot claim that the sum is in ~[0,0].
2226 Note that we are guaranteed to have vr0.type == vr1.type at
2228 if (code
== PLUS_EXPR
&& vr0
.type
== VR_ANTI_RANGE
)
2230 set_value_range_to_varying (vr
);
2234 /* For operations that make the resulting range directly
2235 proportional to the original ranges, apply the operation to
2236 the same end of each range. */
2237 min
= vrp_int_const_binop (code
, vr0
.min
, vr1
.min
);
2238 max
= vrp_int_const_binop (code
, vr0
.max
, vr1
.max
);
2240 /* If both additions overflowed the range kind is still correct.
2241 This happens regularly with subtracting something in unsigned
2243 ??? See PR30318 for all the cases we do not handle. */
2244 if (code
== PLUS_EXPR
2245 && (TREE_OVERFLOW (min
) && !is_overflow_infinity (min
))
2246 && (TREE_OVERFLOW (max
) && !is_overflow_infinity (max
)))
2248 min
= build_int_cst_wide (TREE_TYPE (min
),
2249 TREE_INT_CST_LOW (min
),
2250 TREE_INT_CST_HIGH (min
));
2251 max
= build_int_cst_wide (TREE_TYPE (max
),
2252 TREE_INT_CST_LOW (max
),
2253 TREE_INT_CST_HIGH (max
));
2256 else if (code
== MULT_EXPR
2257 || code
== TRUNC_DIV_EXPR
2258 || code
== FLOOR_DIV_EXPR
2259 || code
== CEIL_DIV_EXPR
2260 || code
== EXACT_DIV_EXPR
2261 || code
== ROUND_DIV_EXPR
2262 || code
== RSHIFT_EXPR
)
2268 /* If we have an unsigned MULT_EXPR with two VR_ANTI_RANGEs,
2269 drop to VR_VARYING. It would take more effort to compute a
2270 precise range for such a case. For example, if we have
2271 op0 == 65536 and op1 == 65536 with their ranges both being
2272 ~[0,0] on a 32-bit machine, we would have op0 * op1 == 0, so
2273 we cannot claim that the product is in ~[0,0]. Note that we
2274 are guaranteed to have vr0.type == vr1.type at this
2276 if (code
== MULT_EXPR
2277 && vr0
.type
== VR_ANTI_RANGE
2278 && !TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (op0
)))
2280 set_value_range_to_varying (vr
);
2284 /* If we have a RSHIFT_EXPR with any shift values outside [0..prec-1],
2285 then drop to VR_VARYING. Outside of this range we get undefined
2286 behavior from the shift operation. We cannot even trust
2287 SHIFT_COUNT_TRUNCATED at this stage, because that applies to rtl
2288 shifts, and the operation at the tree level may be widened. */
2289 if (code
== RSHIFT_EXPR
)
2291 if (vr1
.type
== VR_ANTI_RANGE
2292 || !vrp_expr_computes_nonnegative (op1
, &sop
)
2294 (build_int_cst (TREE_TYPE (vr1
.max
),
2295 TYPE_PRECISION (expr_type
) - 1),
2298 set_value_range_to_varying (vr
);
2303 else if ((code
== TRUNC_DIV_EXPR
2304 || code
== FLOOR_DIV_EXPR
2305 || code
== CEIL_DIV_EXPR
2306 || code
== EXACT_DIV_EXPR
2307 || code
== ROUND_DIV_EXPR
)
2308 && (vr0
.type
!= VR_RANGE
|| symbolic_range_p (&vr0
)))
2310 /* For division, if op1 has VR_RANGE but op0 does not, something
2311 can be deduced just from that range. Say [min, max] / [4, max]
2312 gives [min / 4, max / 4] range. */
2313 if (vr1
.type
== VR_RANGE
2314 && !symbolic_range_p (&vr1
)
2315 && !range_includes_zero_p (&vr1
))
2317 vr0
.type
= type
= VR_RANGE
;
2318 vr0
.min
= vrp_val_min (TREE_TYPE (op0
));
2319 vr0
.max
= vrp_val_max (TREE_TYPE (op1
));
2323 set_value_range_to_varying (vr
);
2328 /* For divisions, if op0 is VR_RANGE, we can deduce a range
2329 even if op1 is VR_VARYING, VR_ANTI_RANGE, symbolic or can
2331 if ((code
== TRUNC_DIV_EXPR
2332 || code
== FLOOR_DIV_EXPR
2333 || code
== CEIL_DIV_EXPR
2334 || code
== EXACT_DIV_EXPR
2335 || code
== ROUND_DIV_EXPR
)
2336 && vr0
.type
== VR_RANGE
2337 && (vr1
.type
!= VR_RANGE
2338 || symbolic_range_p (&vr1
)
2339 || range_includes_zero_p (&vr1
)))
2341 tree zero
= build_int_cst (TREE_TYPE (vr0
.min
), 0);
2347 if (vrp_expr_computes_nonnegative (op1
, &sop
) && !sop
)
2349 /* For unsigned division or when divisor is known
2350 to be non-negative, the range has to cover
2351 all numbers from 0 to max for positive max
2352 and all numbers from min to 0 for negative min. */
2353 cmp
= compare_values (vr0
.max
, zero
);
2356 else if (cmp
== 0 || cmp
== 1)
2360 cmp
= compare_values (vr0
.min
, zero
);
2363 else if (cmp
== 0 || cmp
== -1)
2370 /* Otherwise the range is -max .. max or min .. -min
2371 depending on which bound is bigger in absolute value,
2372 as the division can change the sign. */
2373 abs_extent_range (vr
, vr0
.min
, vr0
.max
);
2376 if (type
== VR_VARYING
)
2378 set_value_range_to_varying (vr
);
2383 /* Multiplications and divisions are a bit tricky to handle,
2384 depending on the mix of signs we have in the two ranges, we
2385 need to operate on different values to get the minimum and
2386 maximum values for the new range. One approach is to figure
2387 out all the variations of range combinations and do the
2390 However, this involves several calls to compare_values and it
2391 is pretty convoluted. It's simpler to do the 4 operations
2392 (MIN0 OP MIN1, MIN0 OP MAX1, MAX0 OP MIN1 and MAX0 OP MAX0 OP
2393 MAX1) and then figure the smallest and largest values to form
2397 gcc_assert ((vr0
.type
== VR_RANGE
2398 || (code
== MULT_EXPR
&& vr0
.type
== VR_ANTI_RANGE
))
2399 && vr0
.type
== vr1
.type
);
2401 /* Compute the 4 cross operations. */
2403 val
[0] = vrp_int_const_binop (code
, vr0
.min
, vr1
.min
);
2404 if (val
[0] == NULL_TREE
)
2407 if (vr1
.max
== vr1
.min
)
2411 val
[1] = vrp_int_const_binop (code
, vr0
.min
, vr1
.max
);
2412 if (val
[1] == NULL_TREE
)
2416 if (vr0
.max
== vr0
.min
)
2420 val
[2] = vrp_int_const_binop (code
, vr0
.max
, vr1
.min
);
2421 if (val
[2] == NULL_TREE
)
2425 if (vr0
.min
== vr0
.max
|| vr1
.min
== vr1
.max
)
2429 val
[3] = vrp_int_const_binop (code
, vr0
.max
, vr1
.max
);
2430 if (val
[3] == NULL_TREE
)
2436 set_value_range_to_varying (vr
);
2440 /* Set MIN to the minimum of VAL[i] and MAX to the maximum
2444 for (i
= 1; i
< 4; i
++)
2446 if (!is_gimple_min_invariant (min
)
2447 || (TREE_OVERFLOW (min
) && !is_overflow_infinity (min
))
2448 || !is_gimple_min_invariant (max
)
2449 || (TREE_OVERFLOW (max
) && !is_overflow_infinity (max
)))
2454 if (!is_gimple_min_invariant (val
[i
])
2455 || (TREE_OVERFLOW (val
[i
])
2456 && !is_overflow_infinity (val
[i
])))
2458 /* If we found an overflowed value, set MIN and MAX
2459 to it so that we set the resulting range to
2465 if (compare_values (val
[i
], min
) == -1)
2468 if (compare_values (val
[i
], max
) == 1)
2474 else if (code
== MINUS_EXPR
)
2476 /* If we have a MINUS_EXPR with two VR_ANTI_RANGEs, drop to
2477 VR_VARYING. It would take more effort to compute a precise
2478 range for such a case. For example, if we have op0 == 1 and
2479 op1 == 1 with their ranges both being ~[0,0], we would have
2480 op0 - op1 == 0, so we cannot claim that the difference is in
2481 ~[0,0]. Note that we are guaranteed to have
2482 vr0.type == vr1.type at this point. */
2483 if (vr0
.type
== VR_ANTI_RANGE
)
2485 set_value_range_to_varying (vr
);
2489 /* For MINUS_EXPR, apply the operation to the opposite ends of
2491 min
= vrp_int_const_binop (code
, vr0
.min
, vr1
.max
);
2492 max
= vrp_int_const_binop (code
, vr0
.max
, vr1
.min
);
2494 else if (code
== BIT_AND_EXPR
)
2496 if (vr0
.type
== VR_RANGE
2497 && vr0
.min
== vr0
.max
2498 && TREE_CODE (vr0
.max
) == INTEGER_CST
2499 && !TREE_OVERFLOW (vr0
.max
)
2500 && tree_int_cst_sgn (vr0
.max
) >= 0)
2502 min
= build_int_cst (expr_type
, 0);
2505 else if (vr1
.type
== VR_RANGE
2506 && vr1
.min
== vr1
.max
2507 && TREE_CODE (vr1
.max
) == INTEGER_CST
2508 && !TREE_OVERFLOW (vr1
.max
)
2509 && tree_int_cst_sgn (vr1
.max
) >= 0)
2512 min
= build_int_cst (expr_type
, 0);
2517 set_value_range_to_varying (vr
);
2521 else if (code
== BIT_IOR_EXPR
)
2523 if (vr0
.type
== VR_RANGE
2524 && vr1
.type
== VR_RANGE
2525 && TREE_CODE (vr0
.min
) == INTEGER_CST
2526 && TREE_CODE (vr1
.min
) == INTEGER_CST
2527 && TREE_CODE (vr0
.max
) == INTEGER_CST
2528 && TREE_CODE (vr1
.max
) == INTEGER_CST
2529 && tree_int_cst_sgn (vr0
.min
) >= 0
2530 && tree_int_cst_sgn (vr1
.min
) >= 0)
2532 double_int vr0_max
= tree_to_double_int (vr0
.max
);
2533 double_int vr1_max
= tree_to_double_int (vr1
.max
);
2536 /* Set all bits to the right of the most significant one to 1.
2537 For example, [0, 4] | [4, 4] = [4, 7]. */
2538 ior_max
.low
= vr0_max
.low
| vr1_max
.low
;
2539 ior_max
.high
= vr0_max
.high
| vr1_max
.high
;
2540 if (ior_max
.high
!= 0)
2542 ior_max
.low
= ~(unsigned HOST_WIDE_INT
)0u;
2543 ior_max
.high
|= ((HOST_WIDE_INT
) 1
2544 << floor_log2 (ior_max
.high
)) - 1;
2546 else if (ior_max
.low
!= 0)
2547 ior_max
.low
|= ((unsigned HOST_WIDE_INT
) 1u
2548 << floor_log2 (ior_max
.low
)) - 1;
2550 /* Both of these endpoints are conservative. */
2551 min
= vrp_int_const_binop (MAX_EXPR
, vr0
.min
, vr1
.min
);
2552 max
= double_int_to_tree (expr_type
, ior_max
);
2556 set_value_range_to_varying (vr
);
2563 /* If either MIN or MAX overflowed, then set the resulting range to
2564 VARYING. But we do accept an overflow infinity
2566 if (min
== NULL_TREE
2567 || !is_gimple_min_invariant (min
)
2568 || (TREE_OVERFLOW (min
) && !is_overflow_infinity (min
))
2570 || !is_gimple_min_invariant (max
)
2571 || (TREE_OVERFLOW (max
) && !is_overflow_infinity (max
)))
2573 set_value_range_to_varying (vr
);
2579 2) [-INF, +-INF(OVF)]
2580 3) [+-INF(OVF), +INF]
2581 4) [+-INF(OVF), +-INF(OVF)]
2582 We learn nothing when we have INF and INF(OVF) on both sides.
2583 Note that we do accept [-INF, -INF] and [+INF, +INF] without
2585 if ((vrp_val_is_min (min
) || is_overflow_infinity (min
))
2586 && (vrp_val_is_max (max
) || is_overflow_infinity (max
)))
2588 set_value_range_to_varying (vr
);
2592 cmp
= compare_values (min
, max
);
2593 if (cmp
== -2 || cmp
== 1)
2595 /* If the new range has its limits swapped around (MIN > MAX),
2596 then the operation caused one of them to wrap around, mark
2597 the new range VARYING. */
2598 set_value_range_to_varying (vr
);
2601 set_value_range (vr
, type
, min
, max
, NULL
);
2605 /* Extract range information from a unary expression EXPR based on
2606 the range of its operand and the expression code. */
2609 extract_range_from_unary_expr (value_range_t
*vr
, enum tree_code code
,
2610 tree type
, tree op0
)
2614 value_range_t vr0
= { VR_UNDEFINED
, NULL_TREE
, NULL_TREE
, NULL
};
2616 /* Refuse to operate on certain unary expressions for which we
2617 cannot easily determine a resulting range. */
2618 if (code
== FIX_TRUNC_EXPR
2619 || code
== FLOAT_EXPR
2620 || code
== BIT_NOT_EXPR
2621 || code
== CONJ_EXPR
)
2623 /* We can still do constant propagation here. */
2624 if ((op0
= op_with_constant_singleton_value_range (op0
)) != NULL_TREE
)
2626 tree tem
= fold_unary (code
, type
, op0
);
2628 && is_gimple_min_invariant (tem
)
2629 && !is_overflow_infinity (tem
))
2631 set_value_range (vr
, VR_RANGE
, tem
, tem
, NULL
);
2635 set_value_range_to_varying (vr
);
2639 /* Get value ranges for the operand. For constant operands, create
2640 a new value range with the operand to simplify processing. */
2641 if (TREE_CODE (op0
) == SSA_NAME
)
2642 vr0
= *(get_value_range (op0
));
2643 else if (is_gimple_min_invariant (op0
))
2644 set_value_range_to_value (&vr0
, op0
, NULL
);
2646 set_value_range_to_varying (&vr0
);
2648 /* If VR0 is UNDEFINED, so is the result. */
2649 if (vr0
.type
== VR_UNDEFINED
)
2651 set_value_range_to_undefined (vr
);
2655 /* Refuse to operate on symbolic ranges, or if neither operand is
2656 a pointer or integral type. */
2657 if ((!INTEGRAL_TYPE_P (TREE_TYPE (op0
))
2658 && !POINTER_TYPE_P (TREE_TYPE (op0
)))
2659 || (vr0
.type
!= VR_VARYING
2660 && symbolic_range_p (&vr0
)))
2662 set_value_range_to_varying (vr
);
2666 /* If the expression involves pointers, we are only interested in
2667 determining if it evaluates to NULL [0, 0] or non-NULL (~[0, 0]). */
2668 if (POINTER_TYPE_P (type
) || POINTER_TYPE_P (TREE_TYPE (op0
)))
2673 if (range_is_nonnull (&vr0
)
2674 || (tree_unary_nonzero_warnv_p (code
, type
, op0
, &sop
)
2676 set_value_range_to_nonnull (vr
, type
);
2677 else if (range_is_null (&vr0
))
2678 set_value_range_to_null (vr
, type
);
2680 set_value_range_to_varying (vr
);
2685 /* Handle unary expressions on integer ranges. */
2686 if (CONVERT_EXPR_CODE_P (code
)
2687 && INTEGRAL_TYPE_P (type
)
2688 && INTEGRAL_TYPE_P (TREE_TYPE (op0
)))
2690 tree inner_type
= TREE_TYPE (op0
);
2691 tree outer_type
= type
;
2693 /* If VR0 is varying and we increase the type precision, assume
2694 a full range for the following transformation. */
2695 if (vr0
.type
== VR_VARYING
2696 && TYPE_PRECISION (inner_type
) < TYPE_PRECISION (outer_type
))
2698 vr0
.type
= VR_RANGE
;
2699 vr0
.min
= TYPE_MIN_VALUE (inner_type
);
2700 vr0
.max
= TYPE_MAX_VALUE (inner_type
);
2703 /* If VR0 is a constant range or anti-range and the conversion is
2704 not truncating we can convert the min and max values and
2705 canonicalize the resulting range. Otherwise we can do the
2706 conversion if the size of the range is less than what the
2707 precision of the target type can represent and the range is
2708 not an anti-range. */
2709 if ((vr0
.type
== VR_RANGE
2710 || vr0
.type
== VR_ANTI_RANGE
)
2711 && TREE_CODE (vr0
.min
) == INTEGER_CST
2712 && TREE_CODE (vr0
.max
) == INTEGER_CST
2713 && !is_overflow_infinity (vr0
.min
)
2714 && !is_overflow_infinity (vr0
.max
)
2715 && (TYPE_PRECISION (outer_type
) >= TYPE_PRECISION (inner_type
)
2716 || (vr0
.type
== VR_RANGE
2717 && integer_zerop (int_const_binop (RSHIFT_EXPR
,
2718 int_const_binop (MINUS_EXPR
, vr0
.max
, vr0
.min
, 0),
2719 size_int (TYPE_PRECISION (outer_type
)), 0)))))
2721 tree new_min
, new_max
;
2722 new_min
= force_fit_type_double (outer_type
,
2723 TREE_INT_CST_LOW (vr0
.min
),
2724 TREE_INT_CST_HIGH (vr0
.min
), 0, 0);
2725 new_max
= force_fit_type_double (outer_type
,
2726 TREE_INT_CST_LOW (vr0
.max
),
2727 TREE_INT_CST_HIGH (vr0
.max
), 0, 0);
2728 set_and_canonicalize_value_range (vr
, vr0
.type
,
2729 new_min
, new_max
, NULL
);
2733 set_value_range_to_varying (vr
);
2737 /* Conversion of a VR_VARYING value to a wider type can result
2738 in a usable range. So wait until after we've handled conversions
2739 before dropping the result to VR_VARYING if we had a source
2740 operand that is VR_VARYING. */
2741 if (vr0
.type
== VR_VARYING
)
2743 set_value_range_to_varying (vr
);
2747 /* Apply the operation to each end of the range and see what we end
2749 if (code
== NEGATE_EXPR
2750 && !TYPE_UNSIGNED (type
))
2752 /* NEGATE_EXPR flips the range around. We need to treat
2753 TYPE_MIN_VALUE specially. */
2754 if (is_positive_overflow_infinity (vr0
.max
))
2755 min
= negative_overflow_infinity (type
);
2756 else if (is_negative_overflow_infinity (vr0
.max
))
2757 min
= positive_overflow_infinity (type
);
2758 else if (!vrp_val_is_min (vr0
.max
))
2759 min
= fold_unary_to_constant (code
, type
, vr0
.max
);
2760 else if (needs_overflow_infinity (type
))
2762 if (supports_overflow_infinity (type
)
2763 && !is_overflow_infinity (vr0
.min
)
2764 && !vrp_val_is_min (vr0
.min
))
2765 min
= positive_overflow_infinity (type
);
2768 set_value_range_to_varying (vr
);
2773 min
= TYPE_MIN_VALUE (type
);
2775 if (is_positive_overflow_infinity (vr0
.min
))
2776 max
= negative_overflow_infinity (type
);
2777 else if (is_negative_overflow_infinity (vr0
.min
))
2778 max
= positive_overflow_infinity (type
);
2779 else if (!vrp_val_is_min (vr0
.min
))
2780 max
= fold_unary_to_constant (code
, type
, vr0
.min
);
2781 else if (needs_overflow_infinity (type
))
2783 if (supports_overflow_infinity (type
))
2784 max
= positive_overflow_infinity (type
);
2787 set_value_range_to_varying (vr
);
2792 max
= TYPE_MIN_VALUE (type
);
2794 else if (code
== NEGATE_EXPR
2795 && TYPE_UNSIGNED (type
))
2797 if (!range_includes_zero_p (&vr0
))
2799 max
= fold_unary_to_constant (code
, type
, vr0
.min
);
2800 min
= fold_unary_to_constant (code
, type
, vr0
.max
);
2804 if (range_is_null (&vr0
))
2805 set_value_range_to_null (vr
, type
);
2807 set_value_range_to_varying (vr
);
2811 else if (code
== ABS_EXPR
2812 && !TYPE_UNSIGNED (type
))
2814 /* -TYPE_MIN_VALUE = TYPE_MIN_VALUE with flag_wrapv so we can't get a
2816 if (!TYPE_OVERFLOW_UNDEFINED (type
)
2817 && ((vr0
.type
== VR_RANGE
2818 && vrp_val_is_min (vr0
.min
))
2819 || (vr0
.type
== VR_ANTI_RANGE
2820 && !vrp_val_is_min (vr0
.min
)
2821 && !range_includes_zero_p (&vr0
))))
2823 set_value_range_to_varying (vr
);
2827 /* ABS_EXPR may flip the range around, if the original range
2828 included negative values. */
2829 if (is_overflow_infinity (vr0
.min
))
2830 min
= positive_overflow_infinity (type
);
2831 else if (!vrp_val_is_min (vr0
.min
))
2832 min
= fold_unary_to_constant (code
, type
, vr0
.min
);
2833 else if (!needs_overflow_infinity (type
))
2834 min
= TYPE_MAX_VALUE (type
);
2835 else if (supports_overflow_infinity (type
))
2836 min
= positive_overflow_infinity (type
);
2839 set_value_range_to_varying (vr
);
2843 if (is_overflow_infinity (vr0
.max
))
2844 max
= positive_overflow_infinity (type
);
2845 else if (!vrp_val_is_min (vr0
.max
))
2846 max
= fold_unary_to_constant (code
, type
, vr0
.max
);
2847 else if (!needs_overflow_infinity (type
))
2848 max
= TYPE_MAX_VALUE (type
);
2849 else if (supports_overflow_infinity (type
)
2850 /* We shouldn't generate [+INF, +INF] as set_value_range
2851 doesn't like this and ICEs. */
2852 && !is_positive_overflow_infinity (min
))
2853 max
= positive_overflow_infinity (type
);
2856 set_value_range_to_varying (vr
);
2860 cmp
= compare_values (min
, max
);
2862 /* If a VR_ANTI_RANGEs contains zero, then we have
2863 ~[-INF, min(MIN, MAX)]. */
2864 if (vr0
.type
== VR_ANTI_RANGE
)
2866 if (range_includes_zero_p (&vr0
))
2868 /* Take the lower of the two values. */
2872 /* Create ~[-INF, min (abs(MIN), abs(MAX))]
2873 or ~[-INF + 1, min (abs(MIN), abs(MAX))] when
2874 flag_wrapv is set and the original anti-range doesn't include
2875 TYPE_MIN_VALUE, remember -TYPE_MIN_VALUE = TYPE_MIN_VALUE. */
2876 if (TYPE_OVERFLOW_WRAPS (type
))
2878 tree type_min_value
= TYPE_MIN_VALUE (type
);
2880 min
= (vr0
.min
!= type_min_value
2881 ? int_const_binop (PLUS_EXPR
, type_min_value
,
2882 integer_one_node
, 0)
2887 if (overflow_infinity_range_p (&vr0
))
2888 min
= negative_overflow_infinity (type
);
2890 min
= TYPE_MIN_VALUE (type
);
2895 /* All else has failed, so create the range [0, INF], even for
2896 flag_wrapv since TYPE_MIN_VALUE is in the original
2898 vr0
.type
= VR_RANGE
;
2899 min
= build_int_cst (type
, 0);
2900 if (needs_overflow_infinity (type
))
2902 if (supports_overflow_infinity (type
))
2903 max
= positive_overflow_infinity (type
);
2906 set_value_range_to_varying (vr
);
2911 max
= TYPE_MAX_VALUE (type
);
2915 /* If the range contains zero then we know that the minimum value in the
2916 range will be zero. */
2917 else if (range_includes_zero_p (&vr0
))
2921 min
= build_int_cst (type
, 0);
2925 /* If the range was reversed, swap MIN and MAX. */
2936 /* Otherwise, operate on each end of the range. */
2937 min
= fold_unary_to_constant (code
, type
, vr0
.min
);
2938 max
= fold_unary_to_constant (code
, type
, vr0
.max
);
2940 if (needs_overflow_infinity (type
))
2942 gcc_assert (code
!= NEGATE_EXPR
&& code
!= ABS_EXPR
);
2944 /* If both sides have overflowed, we don't know
2946 if ((is_overflow_infinity (vr0
.min
)
2947 || TREE_OVERFLOW (min
))
2948 && (is_overflow_infinity (vr0
.max
)
2949 || TREE_OVERFLOW (max
)))
2951 set_value_range_to_varying (vr
);
2955 if (is_overflow_infinity (vr0
.min
))
2957 else if (TREE_OVERFLOW (min
))
2959 if (supports_overflow_infinity (type
))
2960 min
= (tree_int_cst_sgn (min
) >= 0
2961 ? positive_overflow_infinity (TREE_TYPE (min
))
2962 : negative_overflow_infinity (TREE_TYPE (min
)));
2965 set_value_range_to_varying (vr
);
2970 if (is_overflow_infinity (vr0
.max
))
2972 else if (TREE_OVERFLOW (max
))
2974 if (supports_overflow_infinity (type
))
2975 max
= (tree_int_cst_sgn (max
) >= 0
2976 ? positive_overflow_infinity (TREE_TYPE (max
))
2977 : negative_overflow_infinity (TREE_TYPE (max
)));
2980 set_value_range_to_varying (vr
);
2987 cmp
= compare_values (min
, max
);
2988 if (cmp
== -2 || cmp
== 1)
2990 /* If the new range has its limits swapped around (MIN > MAX),
2991 then the operation caused one of them to wrap around, mark
2992 the new range VARYING. */
2993 set_value_range_to_varying (vr
);
2996 set_value_range (vr
, vr0
.type
, min
, max
, NULL
);
3000 /* Extract range information from a conditional expression EXPR based on
3001 the ranges of each of its operands and the expression code. */
3004 extract_range_from_cond_expr (value_range_t
*vr
, tree expr
)
3007 value_range_t vr0
= { VR_UNDEFINED
, NULL_TREE
, NULL_TREE
, NULL
};
3008 value_range_t vr1
= { VR_UNDEFINED
, NULL_TREE
, NULL_TREE
, NULL
};
3010 /* Get value ranges for each operand. For constant operands, create
3011 a new value range with the operand to simplify processing. */
3012 op0
= COND_EXPR_THEN (expr
);
3013 if (TREE_CODE (op0
) == SSA_NAME
)
3014 vr0
= *(get_value_range (op0
));
3015 else if (is_gimple_min_invariant (op0
))
3016 set_value_range_to_value (&vr0
, op0
, NULL
);
3018 set_value_range_to_varying (&vr0
);
3020 op1
= COND_EXPR_ELSE (expr
);
3021 if (TREE_CODE (op1
) == SSA_NAME
)
3022 vr1
= *(get_value_range (op1
));
3023 else if (is_gimple_min_invariant (op1
))
3024 set_value_range_to_value (&vr1
, op1
, NULL
);
3026 set_value_range_to_varying (&vr1
);
3028 /* The resulting value range is the union of the operand ranges */
3029 vrp_meet (&vr0
, &vr1
);
3030 copy_value_range (vr
, &vr0
);
3034 /* Extract range information from a comparison expression EXPR based
3035 on the range of its operand and the expression code. */
3038 extract_range_from_comparison (value_range_t
*vr
, enum tree_code code
,
3039 tree type
, tree op0
, tree op1
)
3044 val
= vrp_evaluate_conditional_warnv_with_ops (code
, op0
, op1
, false, &sop
,
3047 /* A disadvantage of using a special infinity as an overflow
3048 representation is that we lose the ability to record overflow
3049 when we don't have an infinity. So we have to ignore a result
3050 which relies on overflow. */
3052 if (val
&& !is_overflow_infinity (val
) && !sop
)
3054 /* Since this expression was found on the RHS of an assignment,
3055 its type may be different from _Bool. Convert VAL to EXPR's
3057 val
= fold_convert (type
, val
);
3058 if (is_gimple_min_invariant (val
))
3059 set_value_range_to_value (vr
, val
, vr
->equiv
);
3061 set_value_range (vr
, VR_RANGE
, val
, val
, vr
->equiv
);
3064 /* The result of a comparison is always true or false. */
3065 set_value_range_to_truthvalue (vr
, type
);
3068 /* Try to derive a nonnegative or nonzero range out of STMT relying
3069 primarily on generic routines in fold in conjunction with range data.
3070 Store the result in *VR */
3073 extract_range_basic (value_range_t
*vr
, gimple stmt
)
3076 tree type
= gimple_expr_type (stmt
);
3078 if (INTEGRAL_TYPE_P (type
)
3079 && gimple_stmt_nonnegative_warnv_p (stmt
, &sop
))
3080 set_value_range_to_nonnegative (vr
, type
,
3081 sop
|| stmt_overflow_infinity (stmt
));
3082 else if (vrp_stmt_computes_nonzero (stmt
, &sop
)
3084 set_value_range_to_nonnull (vr
, type
);
3086 set_value_range_to_varying (vr
);
3090 /* Try to compute a useful range out of assignment STMT and store it
3094 extract_range_from_assignment (value_range_t
*vr
, gimple stmt
)
3096 enum tree_code code
= gimple_assign_rhs_code (stmt
);
3098 if (code
== ASSERT_EXPR
)
3099 extract_range_from_assert (vr
, gimple_assign_rhs1 (stmt
));
3100 else if (code
== SSA_NAME
)
3101 extract_range_from_ssa_name (vr
, gimple_assign_rhs1 (stmt
));
3102 else if (TREE_CODE_CLASS (code
) == tcc_binary
3103 || code
== TRUTH_AND_EXPR
3104 || code
== TRUTH_OR_EXPR
3105 || code
== TRUTH_XOR_EXPR
)
3106 extract_range_from_binary_expr (vr
, gimple_assign_rhs_code (stmt
),
3107 gimple_expr_type (stmt
),
3108 gimple_assign_rhs1 (stmt
),
3109 gimple_assign_rhs2 (stmt
));
3110 else if (TREE_CODE_CLASS (code
) == tcc_unary
)
3111 extract_range_from_unary_expr (vr
, gimple_assign_rhs_code (stmt
),
3112 gimple_expr_type (stmt
),
3113 gimple_assign_rhs1 (stmt
));
3114 else if (code
== COND_EXPR
)
3115 extract_range_from_cond_expr (vr
, gimple_assign_rhs1 (stmt
));
3116 else if (TREE_CODE_CLASS (code
) == tcc_comparison
)
3117 extract_range_from_comparison (vr
, gimple_assign_rhs_code (stmt
),
3118 gimple_expr_type (stmt
),
3119 gimple_assign_rhs1 (stmt
),
3120 gimple_assign_rhs2 (stmt
));
3121 else if (get_gimple_rhs_class (code
) == GIMPLE_SINGLE_RHS
3122 && is_gimple_min_invariant (gimple_assign_rhs1 (stmt
)))
3123 set_value_range_to_value (vr
, gimple_assign_rhs1 (stmt
), NULL
);
3125 set_value_range_to_varying (vr
);
3127 if (vr
->type
== VR_VARYING
)
3128 extract_range_basic (vr
, stmt
);
3131 /* Given a range VR, a LOOP and a variable VAR, determine whether it
3132 would be profitable to adjust VR using scalar evolution information
3133 for VAR. If so, update VR with the new limits. */
3136 adjust_range_with_scev (value_range_t
*vr
, struct loop
*loop
,
3137 gimple stmt
, tree var
)
3139 tree init
, step
, chrec
, tmin
, tmax
, min
, max
, type
;
3140 enum ev_direction dir
;
3142 /* TODO. Don't adjust anti-ranges. An anti-range may provide
3143 better opportunities than a regular range, but I'm not sure. */
3144 if (vr
->type
== VR_ANTI_RANGE
)
3147 chrec
= instantiate_parameters (loop
, analyze_scalar_evolution (loop
, var
));
3149 /* Like in PR19590, scev can return a constant function. */
3150 if (is_gimple_min_invariant (chrec
))
3152 set_value_range_to_value (vr
, chrec
, vr
->equiv
);
3156 if (TREE_CODE (chrec
) != POLYNOMIAL_CHREC
)
3159 init
= initial_condition_in_loop_num (chrec
, loop
->num
);
3160 step
= evolution_part_in_loop_num (chrec
, loop
->num
);
3162 /* If STEP is symbolic, we can't know whether INIT will be the
3163 minimum or maximum value in the range. Also, unless INIT is
3164 a simple expression, compare_values and possibly other functions
3165 in tree-vrp won't be able to handle it. */
3166 if (step
== NULL_TREE
3167 || !is_gimple_min_invariant (step
)
3168 || !valid_value_p (init
))
3171 dir
= scev_direction (chrec
);
3172 if (/* Do not adjust ranges if we do not know whether the iv increases
3173 or decreases, ... */
3174 dir
== EV_DIR_UNKNOWN
3175 /* ... or if it may wrap. */
3176 || scev_probably_wraps_p (init
, step
, stmt
, get_chrec_loop (chrec
),
3180 /* We use TYPE_MIN_VALUE and TYPE_MAX_VALUE here instead of
3181 negative_overflow_infinity and positive_overflow_infinity,
3182 because we have concluded that the loop probably does not
3185 type
= TREE_TYPE (var
);
3186 if (POINTER_TYPE_P (type
) || !TYPE_MIN_VALUE (type
))
3187 tmin
= lower_bound_in_type (type
, type
);
3189 tmin
= TYPE_MIN_VALUE (type
);
3190 if (POINTER_TYPE_P (type
) || !TYPE_MAX_VALUE (type
))
3191 tmax
= upper_bound_in_type (type
, type
);
3193 tmax
= TYPE_MAX_VALUE (type
);
3195 if (vr
->type
== VR_VARYING
|| vr
->type
== VR_UNDEFINED
)
3200 /* For VARYING or UNDEFINED ranges, just about anything we get
3201 from scalar evolutions should be better. */
3203 if (dir
== EV_DIR_DECREASES
)
3208 /* If we would create an invalid range, then just assume we
3209 know absolutely nothing. This may be over-conservative,
3210 but it's clearly safe, and should happen only in unreachable
3211 parts of code, or for invalid programs. */
3212 if (compare_values (min
, max
) == 1)
3215 set_value_range (vr
, VR_RANGE
, min
, max
, vr
->equiv
);
3217 else if (vr
->type
== VR_RANGE
)
3222 if (dir
== EV_DIR_DECREASES
)
3224 /* INIT is the maximum value. If INIT is lower than VR->MAX
3225 but no smaller than VR->MIN, set VR->MAX to INIT. */
3226 if (compare_values (init
, max
) == -1)
3230 /* If we just created an invalid range with the minimum
3231 greater than the maximum, we fail conservatively.
3232 This should happen only in unreachable
3233 parts of code, or for invalid programs. */
3234 if (compare_values (min
, max
) == 1)
3238 /* According to the loop information, the variable does not
3239 overflow. If we think it does, probably because of an
3240 overflow due to arithmetic on a different INF value,
3242 if (is_negative_overflow_infinity (min
))
3247 /* If INIT is bigger than VR->MIN, set VR->MIN to INIT. */
3248 if (compare_values (init
, min
) == 1)
3252 /* Again, avoid creating invalid range by failing. */
3253 if (compare_values (min
, max
) == 1)
3257 if (is_positive_overflow_infinity (max
))
3261 set_value_range (vr
, VR_RANGE
, min
, max
, vr
->equiv
);
3265 /* Return true if VAR may overflow at STMT. This checks any available
3266 loop information to see if we can determine that VAR does not
3270 vrp_var_may_overflow (tree var
, gimple stmt
)
3273 tree chrec
, init
, step
;
3275 if (current_loops
== NULL
)
3278 l
= loop_containing_stmt (stmt
);
3282 chrec
= instantiate_parameters (l
, analyze_scalar_evolution (l
, var
));
3283 if (TREE_CODE (chrec
) != POLYNOMIAL_CHREC
)
3286 init
= initial_condition_in_loop_num (chrec
, l
->num
);
3287 step
= evolution_part_in_loop_num (chrec
, l
->num
);
3289 if (step
== NULL_TREE
3290 || !is_gimple_min_invariant (step
)
3291 || !valid_value_p (init
))
3294 /* If we get here, we know something useful about VAR based on the
3295 loop information. If it wraps, it may overflow. */
3297 if (scev_probably_wraps_p (init
, step
, stmt
, get_chrec_loop (chrec
),
3301 if (dump_file
&& (dump_flags
& TDF_DETAILS
) != 0)
3303 print_generic_expr (dump_file
, var
, 0);
3304 fprintf (dump_file
, ": loop information indicates does not overflow\n");
3311 /* Given two numeric value ranges VR0, VR1 and a comparison code COMP:
3313 - Return BOOLEAN_TRUE_NODE if VR0 COMP VR1 always returns true for
3314 all the values in the ranges.
3316 - Return BOOLEAN_FALSE_NODE if the comparison always returns false.
3318 - Return NULL_TREE if it is not always possible to determine the
3319 value of the comparison.
3321 Also set *STRICT_OVERFLOW_P to indicate whether a range with an
3322 overflow infinity was used in the test. */
3326 compare_ranges (enum tree_code comp
, value_range_t
*vr0
, value_range_t
*vr1
,
3327 bool *strict_overflow_p
)
3329 /* VARYING or UNDEFINED ranges cannot be compared. */
3330 if (vr0
->type
== VR_VARYING
3331 || vr0
->type
== VR_UNDEFINED
3332 || vr1
->type
== VR_VARYING
3333 || vr1
->type
== VR_UNDEFINED
)
3336 /* Anti-ranges need to be handled separately. */
3337 if (vr0
->type
== VR_ANTI_RANGE
|| vr1
->type
== VR_ANTI_RANGE
)
3339 /* If both are anti-ranges, then we cannot compute any
3341 if (vr0
->type
== VR_ANTI_RANGE
&& vr1
->type
== VR_ANTI_RANGE
)
3344 /* These comparisons are never statically computable. */
3351 /* Equality can be computed only between a range and an
3352 anti-range. ~[VAL1, VAL2] == [VAL1, VAL2] is always false. */
3353 if (vr0
->type
== VR_RANGE
)
3355 /* To simplify processing, make VR0 the anti-range. */
3356 value_range_t
*tmp
= vr0
;
3361 gcc_assert (comp
== NE_EXPR
|| comp
== EQ_EXPR
);
3363 if (compare_values_warnv (vr0
->min
, vr1
->min
, strict_overflow_p
) == 0
3364 && compare_values_warnv (vr0
->max
, vr1
->max
, strict_overflow_p
) == 0)
3365 return (comp
== NE_EXPR
) ? boolean_true_node
: boolean_false_node
;
3370 if (!usable_range_p (vr0
, strict_overflow_p
)
3371 || !usable_range_p (vr1
, strict_overflow_p
))
3374 /* Simplify processing. If COMP is GT_EXPR or GE_EXPR, switch the
3375 operands around and change the comparison code. */
3376 if (comp
== GT_EXPR
|| comp
== GE_EXPR
)
3379 comp
= (comp
== GT_EXPR
) ? LT_EXPR
: LE_EXPR
;
3385 if (comp
== EQ_EXPR
)
3387 /* Equality may only be computed if both ranges represent
3388 exactly one value. */
3389 if (compare_values_warnv (vr0
->min
, vr0
->max
, strict_overflow_p
) == 0
3390 && compare_values_warnv (vr1
->min
, vr1
->max
, strict_overflow_p
) == 0)
3392 int cmp_min
= compare_values_warnv (vr0
->min
, vr1
->min
,
3394 int cmp_max
= compare_values_warnv (vr0
->max
, vr1
->max
,
3396 if (cmp_min
== 0 && cmp_max
== 0)
3397 return boolean_true_node
;
3398 else if (cmp_min
!= -2 && cmp_max
!= -2)
3399 return boolean_false_node
;
3401 /* If [V0_MIN, V1_MAX] < [V1_MIN, V1_MAX] then V0 != V1. */
3402 else if (compare_values_warnv (vr0
->min
, vr1
->max
,
3403 strict_overflow_p
) == 1
3404 || compare_values_warnv (vr1
->min
, vr0
->max
,
3405 strict_overflow_p
) == 1)
3406 return boolean_false_node
;
3410 else if (comp
== NE_EXPR
)
3414 /* If VR0 is completely to the left or completely to the right
3415 of VR1, they are always different. Notice that we need to
3416 make sure that both comparisons yield similar results to
3417 avoid comparing values that cannot be compared at
3419 cmp1
= compare_values_warnv (vr0
->max
, vr1
->min
, strict_overflow_p
);
3420 cmp2
= compare_values_warnv (vr0
->min
, vr1
->max
, strict_overflow_p
);
3421 if ((cmp1
== -1 && cmp2
== -1) || (cmp1
== 1 && cmp2
== 1))
3422 return boolean_true_node
;
3424 /* If VR0 and VR1 represent a single value and are identical,
3426 else if (compare_values_warnv (vr0
->min
, vr0
->max
,
3427 strict_overflow_p
) == 0
3428 && compare_values_warnv (vr1
->min
, vr1
->max
,
3429 strict_overflow_p
) == 0
3430 && compare_values_warnv (vr0
->min
, vr1
->min
,
3431 strict_overflow_p
) == 0
3432 && compare_values_warnv (vr0
->max
, vr1
->max
,
3433 strict_overflow_p
) == 0)
3434 return boolean_false_node
;
3436 /* Otherwise, they may or may not be different. */
3440 else if (comp
== LT_EXPR
|| comp
== LE_EXPR
)
3444 /* If VR0 is to the left of VR1, return true. */
3445 tst
= compare_values_warnv (vr0
->max
, vr1
->min
, strict_overflow_p
);
3446 if ((comp
== LT_EXPR
&& tst
== -1)
3447 || (comp
== LE_EXPR
&& (tst
== -1 || tst
== 0)))
3449 if (overflow_infinity_range_p (vr0
)
3450 || overflow_infinity_range_p (vr1
))
3451 *strict_overflow_p
= true;
3452 return boolean_true_node
;
3455 /* If VR0 is to the right of VR1, return false. */
3456 tst
= compare_values_warnv (vr0
->min
, vr1
->max
, strict_overflow_p
);
3457 if ((comp
== LT_EXPR
&& (tst
== 0 || tst
== 1))
3458 || (comp
== LE_EXPR
&& tst
== 1))
3460 if (overflow_infinity_range_p (vr0
)
3461 || overflow_infinity_range_p (vr1
))
3462 *strict_overflow_p
= true;
3463 return boolean_false_node
;
3466 /* Otherwise, we don't know. */
3474 /* Given a value range VR, a value VAL and a comparison code COMP, return
3475 BOOLEAN_TRUE_NODE if VR COMP VAL always returns true for all the
3476 values in VR. Return BOOLEAN_FALSE_NODE if the comparison
3477 always returns false. Return NULL_TREE if it is not always
3478 possible to determine the value of the comparison. Also set
3479 *STRICT_OVERFLOW_P to indicate whether a range with an overflow
3480 infinity was used in the test. */
3483 compare_range_with_value (enum tree_code comp
, value_range_t
*vr
, tree val
,
3484 bool *strict_overflow_p
)
3486 if (vr
->type
== VR_VARYING
|| vr
->type
== VR_UNDEFINED
)
3489 /* Anti-ranges need to be handled separately. */
3490 if (vr
->type
== VR_ANTI_RANGE
)
3492 /* For anti-ranges, the only predicates that we can compute at
3493 compile time are equality and inequality. */
3500 /* ~[VAL_1, VAL_2] OP VAL is known if VAL_1 <= VAL <= VAL_2. */
3501 if (value_inside_range (val
, vr
) == 1)
3502 return (comp
== NE_EXPR
) ? boolean_true_node
: boolean_false_node
;
3507 if (!usable_range_p (vr
, strict_overflow_p
))
3510 if (comp
== EQ_EXPR
)
3512 /* EQ_EXPR may only be computed if VR represents exactly
3514 if (compare_values_warnv (vr
->min
, vr
->max
, strict_overflow_p
) == 0)
3516 int cmp
= compare_values_warnv (vr
->min
, val
, strict_overflow_p
);
3518 return boolean_true_node
;
3519 else if (cmp
== -1 || cmp
== 1 || cmp
== 2)
3520 return boolean_false_node
;
3522 else if (compare_values_warnv (val
, vr
->min
, strict_overflow_p
) == -1
3523 || compare_values_warnv (vr
->max
, val
, strict_overflow_p
) == -1)
3524 return boolean_false_node
;
3528 else if (comp
== NE_EXPR
)
3530 /* If VAL is not inside VR, then they are always different. */
3531 if (compare_values_warnv (vr
->max
, val
, strict_overflow_p
) == -1
3532 || compare_values_warnv (vr
->min
, val
, strict_overflow_p
) == 1)
3533 return boolean_true_node
;
3535 /* If VR represents exactly one value equal to VAL, then return
3537 if (compare_values_warnv (vr
->min
, vr
->max
, strict_overflow_p
) == 0
3538 && compare_values_warnv (vr
->min
, val
, strict_overflow_p
) == 0)
3539 return boolean_false_node
;
3541 /* Otherwise, they may or may not be different. */
3544 else if (comp
== LT_EXPR
|| comp
== LE_EXPR
)
3548 /* If VR is to the left of VAL, return true. */
3549 tst
= compare_values_warnv (vr
->max
, val
, strict_overflow_p
);
3550 if ((comp
== LT_EXPR
&& tst
== -1)
3551 || (comp
== LE_EXPR
&& (tst
== -1 || tst
== 0)))
3553 if (overflow_infinity_range_p (vr
))
3554 *strict_overflow_p
= true;
3555 return boolean_true_node
;
3558 /* If VR is to the right of VAL, return false. */
3559 tst
= compare_values_warnv (vr
->min
, val
, strict_overflow_p
);
3560 if ((comp
== LT_EXPR
&& (tst
== 0 || tst
== 1))
3561 || (comp
== LE_EXPR
&& tst
== 1))
3563 if (overflow_infinity_range_p (vr
))
3564 *strict_overflow_p
= true;
3565 return boolean_false_node
;
3568 /* Otherwise, we don't know. */
3571 else if (comp
== GT_EXPR
|| comp
== GE_EXPR
)
3575 /* If VR is to the right of VAL, return true. */
3576 tst
= compare_values_warnv (vr
->min
, val
, strict_overflow_p
);
3577 if ((comp
== GT_EXPR
&& tst
== 1)
3578 || (comp
== GE_EXPR
&& (tst
== 0 || tst
== 1)))
3580 if (overflow_infinity_range_p (vr
))
3581 *strict_overflow_p
= true;
3582 return boolean_true_node
;
3585 /* If VR is to the left of VAL, return false. */
3586 tst
= compare_values_warnv (vr
->max
, val
, strict_overflow_p
);
3587 if ((comp
== GT_EXPR
&& (tst
== -1 || tst
== 0))
3588 || (comp
== GE_EXPR
&& tst
== -1))
3590 if (overflow_infinity_range_p (vr
))
3591 *strict_overflow_p
= true;
3592 return boolean_false_node
;
3595 /* Otherwise, we don't know. */
3603 /* Debugging dumps. */
3605 void dump_value_range (FILE *, value_range_t
*);
3606 void debug_value_range (value_range_t
*);
3607 void dump_all_value_ranges (FILE *);
3608 void debug_all_value_ranges (void);
3609 void dump_vr_equiv (FILE *, bitmap
);
3610 void debug_vr_equiv (bitmap
);
3613 /* Dump value range VR to FILE. */
3616 dump_value_range (FILE *file
, value_range_t
*vr
)
3619 fprintf (file
, "[]");
3620 else if (vr
->type
== VR_UNDEFINED
)
3621 fprintf (file
, "UNDEFINED");
3622 else if (vr
->type
== VR_RANGE
|| vr
->type
== VR_ANTI_RANGE
)
3624 tree type
= TREE_TYPE (vr
->min
);
3626 fprintf (file
, "%s[", (vr
->type
== VR_ANTI_RANGE
) ? "~" : "");
3628 if (is_negative_overflow_infinity (vr
->min
))
3629 fprintf (file
, "-INF(OVF)");
3630 else if (INTEGRAL_TYPE_P (type
)
3631 && !TYPE_UNSIGNED (type
)
3632 && vrp_val_is_min (vr
->min
))
3633 fprintf (file
, "-INF");
3635 print_generic_expr (file
, vr
->min
, 0);
3637 fprintf (file
, ", ");
3639 if (is_positive_overflow_infinity (vr
->max
))
3640 fprintf (file
, "+INF(OVF)");
3641 else if (INTEGRAL_TYPE_P (type
)
3642 && vrp_val_is_max (vr
->max
))
3643 fprintf (file
, "+INF");
3645 print_generic_expr (file
, vr
->max
, 0);
3647 fprintf (file
, "]");
3654 fprintf (file
, " EQUIVALENCES: { ");
3656 EXECUTE_IF_SET_IN_BITMAP (vr
->equiv
, 0, i
, bi
)
3658 print_generic_expr (file
, ssa_name (i
), 0);
3659 fprintf (file
, " ");
3663 fprintf (file
, "} (%u elements)", c
);
3666 else if (vr
->type
== VR_VARYING
)
3667 fprintf (file
, "VARYING");
3669 fprintf (file
, "INVALID RANGE");
3673 /* Dump value range VR to stderr. */
3676 debug_value_range (value_range_t
*vr
)
3678 dump_value_range (stderr
, vr
);
3679 fprintf (stderr
, "\n");
3683 /* Dump value ranges of all SSA_NAMEs to FILE. */
3686 dump_all_value_ranges (FILE *file
)
3690 for (i
= 0; i
< num_ssa_names
; i
++)
3694 print_generic_expr (file
, ssa_name (i
), 0);
3695 fprintf (file
, ": ");
3696 dump_value_range (file
, vr_value
[i
]);
3697 fprintf (file
, "\n");
3701 fprintf (file
, "\n");
3705 /* Dump all value ranges to stderr. */
3708 debug_all_value_ranges (void)
3710 dump_all_value_ranges (stderr
);
3714 /* Given a COND_EXPR COND of the form 'V OP W', and an SSA name V,
3715 create a new SSA name N and return the assertion assignment
3716 'V = ASSERT_EXPR <V, V OP W>'. */
3719 build_assert_expr_for (tree cond
, tree v
)
3724 gcc_assert (TREE_CODE (v
) == SSA_NAME
);
3725 n
= duplicate_ssa_name (v
, NULL
);
3727 if (COMPARISON_CLASS_P (cond
))
3729 tree a
= build2 (ASSERT_EXPR
, TREE_TYPE (v
), v
, cond
);
3730 assertion
= gimple_build_assign (n
, a
);
3732 else if (TREE_CODE (cond
) == TRUTH_NOT_EXPR
)
3734 /* Given !V, build the assignment N = false. */
3735 tree op0
= TREE_OPERAND (cond
, 0);
3736 gcc_assert (op0
== v
);
3737 assertion
= gimple_build_assign (n
, boolean_false_node
);
3739 else if (TREE_CODE (cond
) == SSA_NAME
)
3741 /* Given V, build the assignment N = true. */
3742 gcc_assert (v
== cond
);
3743 assertion
= gimple_build_assign (n
, boolean_true_node
);
3748 SSA_NAME_DEF_STMT (n
) = assertion
;
3750 /* The new ASSERT_EXPR, creates a new SSA name that replaces the
3751 operand of the ASSERT_EXPR. Register the new name and the old one
3752 in the replacement table so that we can fix the SSA web after
3753 adding all the ASSERT_EXPRs. */
3754 register_new_name_mapping (n
, v
);
3760 /* Return false if EXPR is a predicate expression involving floating
3764 fp_predicate (gimple stmt
)
3766 GIMPLE_CHECK (stmt
, GIMPLE_COND
);
3768 return FLOAT_TYPE_P (TREE_TYPE (gimple_cond_lhs (stmt
)));
3772 /* If the range of values taken by OP can be inferred after STMT executes,
3773 return the comparison code (COMP_CODE_P) and value (VAL_P) that
3774 describes the inferred range. Return true if a range could be
3778 infer_value_range (gimple stmt
, tree op
, enum tree_code
*comp_code_p
, tree
*val_p
)
3781 *comp_code_p
= ERROR_MARK
;
3783 /* Do not attempt to infer anything in names that flow through
3785 if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (op
))
3788 /* Similarly, don't infer anything from statements that may throw
3790 if (stmt_could_throw_p (stmt
))
3793 /* If STMT is the last statement of a basic block with no
3794 successors, there is no point inferring anything about any of its
3795 operands. We would not be able to find a proper insertion point
3796 for the assertion, anyway. */
3797 if (stmt_ends_bb_p (stmt
) && EDGE_COUNT (gimple_bb (stmt
)->succs
) == 0)
3800 /* We can only assume that a pointer dereference will yield
3801 non-NULL if -fdelete-null-pointer-checks is enabled. */
3802 if (flag_delete_null_pointer_checks
3803 && POINTER_TYPE_P (TREE_TYPE (op
))
3804 && gimple_code (stmt
) != GIMPLE_ASM
)
3806 unsigned num_uses
, num_loads
, num_stores
;
3808 count_uses_and_derefs (op
, stmt
, &num_uses
, &num_loads
, &num_stores
);
3809 if (num_loads
+ num_stores
> 0)
3811 *val_p
= build_int_cst (TREE_TYPE (op
), 0);
3812 *comp_code_p
= NE_EXPR
;
3821 void dump_asserts_for (FILE *, tree
);
3822 void debug_asserts_for (tree
);
3823 void dump_all_asserts (FILE *);
3824 void debug_all_asserts (void);
3826 /* Dump all the registered assertions for NAME to FILE. */
3829 dump_asserts_for (FILE *file
, tree name
)
3833 fprintf (file
, "Assertions to be inserted for ");
3834 print_generic_expr (file
, name
, 0);
3835 fprintf (file
, "\n");
3837 loc
= asserts_for
[SSA_NAME_VERSION (name
)];
3840 fprintf (file
, "\t");
3841 print_gimple_stmt (file
, gsi_stmt (loc
->si
), 0, 0);
3842 fprintf (file
, "\n\tBB #%d", loc
->bb
->index
);
3845 fprintf (file
, "\n\tEDGE %d->%d", loc
->e
->src
->index
,
3846 loc
->e
->dest
->index
);
3847 dump_edge_info (file
, loc
->e
, 0);
3849 fprintf (file
, "\n\tPREDICATE: ");
3850 print_generic_expr (file
, name
, 0);
3851 fprintf (file
, " %s ", tree_code_name
[(int)loc
->comp_code
]);
3852 print_generic_expr (file
, loc
->val
, 0);
3853 fprintf (file
, "\n\n");
3857 fprintf (file
, "\n");
3861 /* Dump all the registered assertions for NAME to stderr. */
3864 debug_asserts_for (tree name
)
3866 dump_asserts_for (stderr
, name
);
3870 /* Dump all the registered assertions for all the names to FILE. */
3873 dump_all_asserts (FILE *file
)
3878 fprintf (file
, "\nASSERT_EXPRs to be inserted\n\n");
3879 EXECUTE_IF_SET_IN_BITMAP (need_assert_for
, 0, i
, bi
)
3880 dump_asserts_for (file
, ssa_name (i
));
3881 fprintf (file
, "\n");
3885 /* Dump all the registered assertions for all the names to stderr. */
3888 debug_all_asserts (void)
3890 dump_all_asserts (stderr
);
3894 /* If NAME doesn't have an ASSERT_EXPR registered for asserting
3895 'EXPR COMP_CODE VAL' at a location that dominates block BB or
3896 E->DEST, then register this location as a possible insertion point
3897 for ASSERT_EXPR <NAME, EXPR COMP_CODE VAL>.
3899 BB, E and SI provide the exact insertion point for the new
3900 ASSERT_EXPR. If BB is NULL, then the ASSERT_EXPR is to be inserted
3901 on edge E. Otherwise, if E is NULL, the ASSERT_EXPR is inserted on
3902 BB. If SI points to a COND_EXPR or a SWITCH_EXPR statement, then E
3903 must not be NULL. */
3906 register_new_assert_for (tree name
, tree expr
,
3907 enum tree_code comp_code
,
3911 gimple_stmt_iterator si
)
3913 assert_locus_t n
, loc
, last_loc
;
3915 basic_block dest_bb
;
3917 #if defined ENABLE_CHECKING
3918 gcc_assert (bb
== NULL
|| e
== NULL
);
3921 gcc_assert (gimple_code (gsi_stmt (si
)) != GIMPLE_COND
3922 && gimple_code (gsi_stmt (si
)) != GIMPLE_SWITCH
);
3925 /* Never build an assert comparing against an integer constant with
3926 TREE_OVERFLOW set. This confuses our undefined overflow warning
3928 if (TREE_CODE (val
) == INTEGER_CST
3929 && TREE_OVERFLOW (val
))
3930 val
= build_int_cst_wide (TREE_TYPE (val
),
3931 TREE_INT_CST_LOW (val
), TREE_INT_CST_HIGH (val
));
3933 /* The new assertion A will be inserted at BB or E. We need to
3934 determine if the new location is dominated by a previously
3935 registered location for A. If we are doing an edge insertion,
3936 assume that A will be inserted at E->DEST. Note that this is not
3939 If E is a critical edge, it will be split. But even if E is
3940 split, the new block will dominate the same set of blocks that
3943 The reverse, however, is not true, blocks dominated by E->DEST
3944 will not be dominated by the new block created to split E. So,
3945 if the insertion location is on a critical edge, we will not use
3946 the new location to move another assertion previously registered
3947 at a block dominated by E->DEST. */
3948 dest_bb
= (bb
) ? bb
: e
->dest
;
3950 /* If NAME already has an ASSERT_EXPR registered for COMP_CODE and
3951 VAL at a block dominating DEST_BB, then we don't need to insert a new
3952 one. Similarly, if the same assertion already exists at a block
3953 dominated by DEST_BB and the new location is not on a critical
3954 edge, then update the existing location for the assertion (i.e.,
3955 move the assertion up in the dominance tree).
3957 Note, this is implemented as a simple linked list because there
3958 should not be more than a handful of assertions registered per
3959 name. If this becomes a performance problem, a table hashed by
3960 COMP_CODE and VAL could be implemented. */
3961 loc
= asserts_for
[SSA_NAME_VERSION (name
)];
3966 if (loc
->comp_code
== comp_code
3968 || operand_equal_p (loc
->val
, val
, 0))
3969 && (loc
->expr
== expr
3970 || operand_equal_p (loc
->expr
, expr
, 0)))
3972 /* If the assertion NAME COMP_CODE VAL has already been
3973 registered at a basic block that dominates DEST_BB, then
3974 we don't need to insert the same assertion again. Note
3975 that we don't check strict dominance here to avoid
3976 replicating the same assertion inside the same basic
3977 block more than once (e.g., when a pointer is
3978 dereferenced several times inside a block).
3980 An exception to this rule are edge insertions. If the
3981 new assertion is to be inserted on edge E, then it will
3982 dominate all the other insertions that we may want to
3983 insert in DEST_BB. So, if we are doing an edge
3984 insertion, don't do this dominance check. */
3986 && dominated_by_p (CDI_DOMINATORS
, dest_bb
, loc
->bb
))
3989 /* Otherwise, if E is not a critical edge and DEST_BB
3990 dominates the existing location for the assertion, move
3991 the assertion up in the dominance tree by updating its
3992 location information. */
3993 if ((e
== NULL
|| !EDGE_CRITICAL_P (e
))
3994 && dominated_by_p (CDI_DOMINATORS
, loc
->bb
, dest_bb
))
4003 /* Update the last node of the list and move to the next one. */
4008 /* If we didn't find an assertion already registered for
4009 NAME COMP_CODE VAL, add a new one at the end of the list of
4010 assertions associated with NAME. */
4011 n
= XNEW (struct assert_locus_d
);
4015 n
->comp_code
= comp_code
;
4023 asserts_for
[SSA_NAME_VERSION (name
)] = n
;
4025 bitmap_set_bit (need_assert_for
, SSA_NAME_VERSION (name
));
4028 /* (COND_OP0 COND_CODE COND_OP1) is a predicate which uses NAME.
4029 Extract a suitable test code and value and store them into *CODE_P and
4030 *VAL_P so the predicate is normalized to NAME *CODE_P *VAL_P.
4032 If no extraction was possible, return FALSE, otherwise return TRUE.
4034 If INVERT is true, then we invert the result stored into *CODE_P. */
4037 extract_code_and_val_from_cond_with_ops (tree name
, enum tree_code cond_code
,
4038 tree cond_op0
, tree cond_op1
,
4039 bool invert
, enum tree_code
*code_p
,
4042 enum tree_code comp_code
;
4045 /* Otherwise, we have a comparison of the form NAME COMP VAL
4046 or VAL COMP NAME. */
4047 if (name
== cond_op1
)
4049 /* If the predicate is of the form VAL COMP NAME, flip
4050 COMP around because we need to register NAME as the
4051 first operand in the predicate. */
4052 comp_code
= swap_tree_comparison (cond_code
);
4057 /* The comparison is of the form NAME COMP VAL, so the
4058 comparison code remains unchanged. */
4059 comp_code
= cond_code
;
4063 /* Invert the comparison code as necessary. */
4065 comp_code
= invert_tree_comparison (comp_code
, 0);
4067 /* VRP does not handle float types. */
4068 if (SCALAR_FLOAT_TYPE_P (TREE_TYPE (val
)))
4071 /* Do not register always-false predicates.
4072 FIXME: this works around a limitation in fold() when dealing with
4073 enumerations. Given 'enum { N1, N2 } x;', fold will not
4074 fold 'if (x > N2)' to 'if (0)'. */
4075 if ((comp_code
== GT_EXPR
|| comp_code
== LT_EXPR
)
4076 && INTEGRAL_TYPE_P (TREE_TYPE (val
)))
4078 tree min
= TYPE_MIN_VALUE (TREE_TYPE (val
));
4079 tree max
= TYPE_MAX_VALUE (TREE_TYPE (val
));
4081 if (comp_code
== GT_EXPR
4083 || compare_values (val
, max
) == 0))
4086 if (comp_code
== LT_EXPR
4088 || compare_values (val
, min
) == 0))
4091 *code_p
= comp_code
;
4096 /* Try to register an edge assertion for SSA name NAME on edge E for
4097 the condition COND contributing to the conditional jump pointed to by BSI.
4098 Invert the condition COND if INVERT is true.
4099 Return true if an assertion for NAME could be registered. */
4102 register_edge_assert_for_2 (tree name
, edge e
, gimple_stmt_iterator bsi
,
4103 enum tree_code cond_code
,
4104 tree cond_op0
, tree cond_op1
, bool invert
)
4107 enum tree_code comp_code
;
4108 bool retval
= false;
4110 if (!extract_code_and_val_from_cond_with_ops (name
, cond_code
,
4113 invert
, &comp_code
, &val
))
4116 /* Only register an ASSERT_EXPR if NAME was found in the sub-graph
4117 reachable from E. */
4118 if (live_on_edge (e
, name
)
4119 && !has_single_use (name
))
4121 register_new_assert_for (name
, name
, comp_code
, val
, NULL
, e
, bsi
);
4125 /* In the case of NAME <= CST and NAME being defined as
4126 NAME = (unsigned) NAME2 + CST2 we can assert NAME2 >= -CST2
4127 and NAME2 <= CST - CST2. We can do the same for NAME > CST.
4128 This catches range and anti-range tests. */
4129 if ((comp_code
== LE_EXPR
4130 || comp_code
== GT_EXPR
)
4131 && TREE_CODE (val
) == INTEGER_CST
4132 && TYPE_UNSIGNED (TREE_TYPE (val
)))
4134 gimple def_stmt
= SSA_NAME_DEF_STMT (name
);
4135 tree cst2
= NULL_TREE
, name2
= NULL_TREE
, name3
= NULL_TREE
;
4137 /* Extract CST2 from the (optional) addition. */
4138 if (is_gimple_assign (def_stmt
)
4139 && gimple_assign_rhs_code (def_stmt
) == PLUS_EXPR
)
4141 name2
= gimple_assign_rhs1 (def_stmt
);
4142 cst2
= gimple_assign_rhs2 (def_stmt
);
4143 if (TREE_CODE (name2
) == SSA_NAME
4144 && TREE_CODE (cst2
) == INTEGER_CST
)
4145 def_stmt
= SSA_NAME_DEF_STMT (name2
);
4148 /* Extract NAME2 from the (optional) sign-changing cast. */
4149 if (gimple_assign_cast_p (def_stmt
))
4151 if (CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (def_stmt
))
4152 && ! TYPE_UNSIGNED (TREE_TYPE (gimple_assign_rhs1 (def_stmt
)))
4153 && (TYPE_PRECISION (gimple_expr_type (def_stmt
))
4154 == TYPE_PRECISION (TREE_TYPE (gimple_assign_rhs1 (def_stmt
)))))
4155 name3
= gimple_assign_rhs1 (def_stmt
);
4158 /* If name3 is used later, create an ASSERT_EXPR for it. */
4159 if (name3
!= NULL_TREE
4160 && TREE_CODE (name3
) == SSA_NAME
4161 && (cst2
== NULL_TREE
4162 || TREE_CODE (cst2
) == INTEGER_CST
)
4163 && INTEGRAL_TYPE_P (TREE_TYPE (name3
))
4164 && live_on_edge (e
, name3
)
4165 && !has_single_use (name3
))
4169 /* Build an expression for the range test. */
4170 tmp
= build1 (NOP_EXPR
, TREE_TYPE (name
), name3
);
4171 if (cst2
!= NULL_TREE
)
4172 tmp
= build2 (PLUS_EXPR
, TREE_TYPE (name
), tmp
, cst2
);
4176 fprintf (dump_file
, "Adding assert for ");
4177 print_generic_expr (dump_file
, name3
, 0);
4178 fprintf (dump_file
, " from ");
4179 print_generic_expr (dump_file
, tmp
, 0);
4180 fprintf (dump_file
, "\n");
4183 register_new_assert_for (name3
, tmp
, comp_code
, val
, NULL
, e
, bsi
);
4188 /* If name2 is used later, create an ASSERT_EXPR for it. */
4189 if (name2
!= NULL_TREE
4190 && TREE_CODE (name2
) == SSA_NAME
4191 && TREE_CODE (cst2
) == INTEGER_CST
4192 && INTEGRAL_TYPE_P (TREE_TYPE (name2
))
4193 && live_on_edge (e
, name2
)
4194 && !has_single_use (name2
))
4198 /* Build an expression for the range test. */
4200 if (TREE_TYPE (name
) != TREE_TYPE (name2
))
4201 tmp
= build1 (NOP_EXPR
, TREE_TYPE (name
), tmp
);
4202 if (cst2
!= NULL_TREE
)
4203 tmp
= build2 (PLUS_EXPR
, TREE_TYPE (name
), tmp
, cst2
);
4207 fprintf (dump_file
, "Adding assert for ");
4208 print_generic_expr (dump_file
, name2
, 0);
4209 fprintf (dump_file
, " from ");
4210 print_generic_expr (dump_file
, tmp
, 0);
4211 fprintf (dump_file
, "\n");
4214 register_new_assert_for (name2
, tmp
, comp_code
, val
, NULL
, e
, bsi
);
4223 /* OP is an operand of a truth value expression which is known to have
4224 a particular value. Register any asserts for OP and for any
4225 operands in OP's defining statement.
4227 If CODE is EQ_EXPR, then we want to register OP is zero (false),
4228 if CODE is NE_EXPR, then we want to register OP is nonzero (true). */
4231 register_edge_assert_for_1 (tree op
, enum tree_code code
,
4232 edge e
, gimple_stmt_iterator bsi
)
4234 bool retval
= false;
4237 enum tree_code rhs_code
;
4239 /* We only care about SSA_NAMEs. */
4240 if (TREE_CODE (op
) != SSA_NAME
)
4243 /* We know that OP will have a zero or nonzero value. If OP is used
4244 more than once go ahead and register an assert for OP.
4246 The FOUND_IN_SUBGRAPH support is not helpful in this situation as
4247 it will always be set for OP (because OP is used in a COND_EXPR in
4249 if (!has_single_use (op
))
4251 val
= build_int_cst (TREE_TYPE (op
), 0);
4252 register_new_assert_for (op
, op
, code
, val
, NULL
, e
, bsi
);
4256 /* Now look at how OP is set. If it's set from a comparison,
4257 a truth operation or some bit operations, then we may be able
4258 to register information about the operands of that assignment. */
4259 op_def
= SSA_NAME_DEF_STMT (op
);
4260 if (gimple_code (op_def
) != GIMPLE_ASSIGN
)
4263 rhs_code
= gimple_assign_rhs_code (op_def
);
4265 if (TREE_CODE_CLASS (rhs_code
) == tcc_comparison
)
4267 bool invert
= (code
== EQ_EXPR
? true : false);
4268 tree op0
= gimple_assign_rhs1 (op_def
);
4269 tree op1
= gimple_assign_rhs2 (op_def
);
4271 if (TREE_CODE (op0
) == SSA_NAME
)
4272 retval
|= register_edge_assert_for_2 (op0
, e
, bsi
, rhs_code
, op0
, op1
,
4274 if (TREE_CODE (op1
) == SSA_NAME
)
4275 retval
|= register_edge_assert_for_2 (op1
, e
, bsi
, rhs_code
, op0
, op1
,
4278 else if ((code
== NE_EXPR
4279 && (gimple_assign_rhs_code (op_def
) == TRUTH_AND_EXPR
4280 || gimple_assign_rhs_code (op_def
) == BIT_AND_EXPR
))
4282 && (gimple_assign_rhs_code (op_def
) == TRUTH_OR_EXPR
4283 || gimple_assign_rhs_code (op_def
) == BIT_IOR_EXPR
)))
4285 /* Recurse on each operand. */
4286 retval
|= register_edge_assert_for_1 (gimple_assign_rhs1 (op_def
),
4288 retval
|= register_edge_assert_for_1 (gimple_assign_rhs2 (op_def
),
4291 else if (gimple_assign_rhs_code (op_def
) == TRUTH_NOT_EXPR
)
4293 /* Recurse, flipping CODE. */
4294 code
= invert_tree_comparison (code
, false);
4295 retval
|= register_edge_assert_for_1 (gimple_assign_rhs1 (op_def
),
4298 else if (gimple_assign_rhs_code (op_def
) == SSA_NAME
)
4300 /* Recurse through the copy. */
4301 retval
|= register_edge_assert_for_1 (gimple_assign_rhs1 (op_def
),
4304 else if (CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (op_def
)))
4306 /* Recurse through the type conversion. */
4307 retval
|= register_edge_assert_for_1 (gimple_assign_rhs1 (op_def
),
4314 /* Try to register an edge assertion for SSA name NAME on edge E for
4315 the condition COND contributing to the conditional jump pointed to by SI.
4316 Return true if an assertion for NAME could be registered. */
4319 register_edge_assert_for (tree name
, edge e
, gimple_stmt_iterator si
,
4320 enum tree_code cond_code
, tree cond_op0
,
4324 enum tree_code comp_code
;
4325 bool retval
= false;
4326 bool is_else_edge
= (e
->flags
& EDGE_FALSE_VALUE
) != 0;
4328 /* Do not attempt to infer anything in names that flow through
4330 if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (name
))
4333 if (!extract_code_and_val_from_cond_with_ops (name
, cond_code
,
4339 /* Register ASSERT_EXPRs for name. */
4340 retval
|= register_edge_assert_for_2 (name
, e
, si
, cond_code
, cond_op0
,
4341 cond_op1
, is_else_edge
);
4344 /* If COND is effectively an equality test of an SSA_NAME against
4345 the value zero or one, then we may be able to assert values
4346 for SSA_NAMEs which flow into COND. */
4348 /* In the case of NAME == 1 or NAME != 0, for TRUTH_AND_EXPR defining
4349 statement of NAME we can assert both operands of the TRUTH_AND_EXPR
4350 have nonzero value. */
4351 if (((comp_code
== EQ_EXPR
&& integer_onep (val
))
4352 || (comp_code
== NE_EXPR
&& integer_zerop (val
))))
4354 gimple def_stmt
= SSA_NAME_DEF_STMT (name
);
4356 if (is_gimple_assign (def_stmt
)
4357 && (gimple_assign_rhs_code (def_stmt
) == TRUTH_AND_EXPR
4358 || gimple_assign_rhs_code (def_stmt
) == BIT_AND_EXPR
))
4360 tree op0
= gimple_assign_rhs1 (def_stmt
);
4361 tree op1
= gimple_assign_rhs2 (def_stmt
);
4362 retval
|= register_edge_assert_for_1 (op0
, NE_EXPR
, e
, si
);
4363 retval
|= register_edge_assert_for_1 (op1
, NE_EXPR
, e
, si
);
4367 /* In the case of NAME == 0 or NAME != 1, for TRUTH_OR_EXPR defining
4368 statement of NAME we can assert both operands of the TRUTH_OR_EXPR
4370 if (((comp_code
== EQ_EXPR
&& integer_zerop (val
))
4371 || (comp_code
== NE_EXPR
&& integer_onep (val
))))
4373 gimple def_stmt
= SSA_NAME_DEF_STMT (name
);
4375 if (is_gimple_assign (def_stmt
)
4376 && (gimple_assign_rhs_code (def_stmt
) == TRUTH_OR_EXPR
4377 /* For BIT_IOR_EXPR only if NAME == 0 both operands have
4378 necessarily zero value. */
4379 || (comp_code
== EQ_EXPR
4380 && (gimple_assign_rhs_code (def_stmt
) == BIT_IOR_EXPR
))))
4382 tree op0
= gimple_assign_rhs1 (def_stmt
);
4383 tree op1
= gimple_assign_rhs2 (def_stmt
);
4384 retval
|= register_edge_assert_for_1 (op0
, EQ_EXPR
, e
, si
);
4385 retval
|= register_edge_assert_for_1 (op1
, EQ_EXPR
, e
, si
);
4393 /* Determine whether the outgoing edges of BB should receive an
4394 ASSERT_EXPR for each of the operands of BB's LAST statement.
4395 The last statement of BB must be a COND_EXPR.
4397 If any of the sub-graphs rooted at BB have an interesting use of
4398 the predicate operands, an assert location node is added to the
4399 list of assertions for the corresponding operands. */
4402 find_conditional_asserts (basic_block bb
, gimple last
)
4405 gimple_stmt_iterator bsi
;
4411 need_assert
= false;
4412 bsi
= gsi_for_stmt (last
);
4414 /* Look for uses of the operands in each of the sub-graphs
4415 rooted at BB. We need to check each of the outgoing edges
4416 separately, so that we know what kind of ASSERT_EXPR to
4418 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
4423 /* Register the necessary assertions for each operand in the
4424 conditional predicate. */
4425 FOR_EACH_SSA_TREE_OPERAND (op
, last
, iter
, SSA_OP_USE
)
4427 need_assert
|= register_edge_assert_for (op
, e
, bsi
,
4428 gimple_cond_code (last
),
4429 gimple_cond_lhs (last
),
4430 gimple_cond_rhs (last
));
4437 /* Compare two case labels sorting first by the destination label uid
4438 and then by the case value. */
4441 compare_case_labels (const void *p1
, const void *p2
)
4443 const_tree
const case1
= *(const_tree
const*)p1
;
4444 const_tree
const case2
= *(const_tree
const*)p2
;
4445 unsigned int uid1
= DECL_UID (CASE_LABEL (case1
));
4446 unsigned int uid2
= DECL_UID (CASE_LABEL (case2
));
4450 else if (uid1
== uid2
)
4452 /* Make sure the default label is first in a group. */
4453 if (!CASE_LOW (case1
))
4455 else if (!CASE_LOW (case2
))
4458 return tree_int_cst_compare (CASE_LOW (case1
), CASE_LOW (case2
));
4464 /* Determine whether the outgoing edges of BB should receive an
4465 ASSERT_EXPR for each of the operands of BB's LAST statement.
4466 The last statement of BB must be a SWITCH_EXPR.
4468 If any of the sub-graphs rooted at BB have an interesting use of
4469 the predicate operands, an assert location node is added to the
4470 list of assertions for the corresponding operands. */
4473 find_switch_asserts (basic_block bb
, gimple last
)
4476 gimple_stmt_iterator bsi
;
4480 size_t n
= gimple_switch_num_labels(last
);
4481 #if GCC_VERSION >= 4000
4484 /* Work around GCC 3.4 bug (PR 37086). */
4485 volatile unsigned int idx
;
4488 need_assert
= false;
4489 bsi
= gsi_for_stmt (last
);
4490 op
= gimple_switch_index (last
);
4491 if (TREE_CODE (op
) != SSA_NAME
)
4494 /* Build a vector of case labels sorted by destination label. */
4495 vec2
= make_tree_vec (n
);
4496 for (idx
= 0; idx
< n
; ++idx
)
4497 TREE_VEC_ELT (vec2
, idx
) = gimple_switch_label (last
, idx
);
4498 qsort (&TREE_VEC_ELT (vec2
, 0), n
, sizeof (tree
), compare_case_labels
);
4500 for (idx
= 0; idx
< n
; ++idx
)
4503 tree cl
= TREE_VEC_ELT (vec2
, idx
);
4505 min
= CASE_LOW (cl
);
4506 max
= CASE_HIGH (cl
);
4508 /* If there are multiple case labels with the same destination
4509 we need to combine them to a single value range for the edge. */
4511 && CASE_LABEL (cl
) == CASE_LABEL (TREE_VEC_ELT (vec2
, idx
+ 1)))
4513 /* Skip labels until the last of the group. */
4517 && CASE_LABEL (cl
) == CASE_LABEL (TREE_VEC_ELT (vec2
, idx
)));
4520 /* Pick up the maximum of the case label range. */
4521 if (CASE_HIGH (TREE_VEC_ELT (vec2
, idx
)))
4522 max
= CASE_HIGH (TREE_VEC_ELT (vec2
, idx
));
4524 max
= CASE_LOW (TREE_VEC_ELT (vec2
, idx
));
4527 /* Nothing to do if the range includes the default label until we
4528 can register anti-ranges. */
4529 if (min
== NULL_TREE
)
4532 /* Find the edge to register the assert expr on. */
4533 e
= find_edge (bb
, label_to_block (CASE_LABEL (cl
)));
4535 /* Register the necessary assertions for the operand in the
4537 need_assert
|= register_edge_assert_for (op
, e
, bsi
,
4538 max
? GE_EXPR
: EQ_EXPR
,
4540 fold_convert (TREE_TYPE (op
),
4544 need_assert
|= register_edge_assert_for (op
, e
, bsi
, LE_EXPR
,
4546 fold_convert (TREE_TYPE (op
),
4555 /* Traverse all the statements in block BB looking for statements that
4556 may generate useful assertions for the SSA names in their operand.
4557 If a statement produces a useful assertion A for name N_i, then the
4558 list of assertions already generated for N_i is scanned to
4559 determine if A is actually needed.
4561 If N_i already had the assertion A at a location dominating the
4562 current location, then nothing needs to be done. Otherwise, the
4563 new location for A is recorded instead.
4565 1- For every statement S in BB, all the variables used by S are
4566 added to bitmap FOUND_IN_SUBGRAPH.
4568 2- If statement S uses an operand N in a way that exposes a known
4569 value range for N, then if N was not already generated by an
4570 ASSERT_EXPR, create a new assert location for N. For instance,
4571 if N is a pointer and the statement dereferences it, we can
4572 assume that N is not NULL.
4574 3- COND_EXPRs are a special case of #2. We can derive range
4575 information from the predicate but need to insert different
4576 ASSERT_EXPRs for each of the sub-graphs rooted at the
4577 conditional block. If the last statement of BB is a conditional
4578 expression of the form 'X op Y', then
4580 a) Remove X and Y from the set FOUND_IN_SUBGRAPH.
4582 b) If the conditional is the only entry point to the sub-graph
4583 corresponding to the THEN_CLAUSE, recurse into it. On
4584 return, if X and/or Y are marked in FOUND_IN_SUBGRAPH, then
4585 an ASSERT_EXPR is added for the corresponding variable.
4587 c) Repeat step (b) on the ELSE_CLAUSE.
4589 d) Mark X and Y in FOUND_IN_SUBGRAPH.
4598 In this case, an assertion on the THEN clause is useful to
4599 determine that 'a' is always 9 on that edge. However, an assertion
4600 on the ELSE clause would be unnecessary.
4602 4- If BB does not end in a conditional expression, then we recurse
4603 into BB's dominator children.
4605 At the end of the recursive traversal, every SSA name will have a
4606 list of locations where ASSERT_EXPRs should be added. When a new
4607 location for name N is found, it is registered by calling
4608 register_new_assert_for. That function keeps track of all the
4609 registered assertions to prevent adding unnecessary assertions.
4610 For instance, if a pointer P_4 is dereferenced more than once in a
4611 dominator tree, only the location dominating all the dereference of
4612 P_4 will receive an ASSERT_EXPR.
4614 If this function returns true, then it means that there are names
4615 for which we need to generate ASSERT_EXPRs. Those assertions are
4616 inserted by process_assert_insertions. */
4619 find_assert_locations_1 (basic_block bb
, sbitmap live
)
4621 gimple_stmt_iterator si
;
4626 need_assert
= false;
4627 last
= last_stmt (bb
);
4629 /* If BB's last statement is a conditional statement involving integer
4630 operands, determine if we need to add ASSERT_EXPRs. */
4632 && gimple_code (last
) == GIMPLE_COND
4633 && !fp_predicate (last
)
4634 && !ZERO_SSA_OPERANDS (last
, SSA_OP_USE
))
4635 need_assert
|= find_conditional_asserts (bb
, last
);
4637 /* If BB's last statement is a switch statement involving integer
4638 operands, determine if we need to add ASSERT_EXPRs. */
4640 && gimple_code (last
) == GIMPLE_SWITCH
4641 && !ZERO_SSA_OPERANDS (last
, SSA_OP_USE
))
4642 need_assert
|= find_switch_asserts (bb
, last
);
4644 /* Traverse all the statements in BB marking used names and looking
4645 for statements that may infer assertions for their used operands. */
4646 for (si
= gsi_start_bb (bb
); !gsi_end_p (si
); gsi_next (&si
))
4652 stmt
= gsi_stmt (si
);
4654 if (is_gimple_debug (stmt
))
4657 /* See if we can derive an assertion for any of STMT's operands. */
4658 FOR_EACH_SSA_TREE_OPERAND (op
, stmt
, i
, SSA_OP_USE
)
4661 enum tree_code comp_code
;
4663 /* Mark OP in our live bitmap. */
4664 SET_BIT (live
, SSA_NAME_VERSION (op
));
4666 /* If OP is used in such a way that we can infer a value
4667 range for it, and we don't find a previous assertion for
4668 it, create a new assertion location node for OP. */
4669 if (infer_value_range (stmt
, op
, &comp_code
, &value
))
4671 /* If we are able to infer a nonzero value range for OP,
4672 then walk backwards through the use-def chain to see if OP
4673 was set via a typecast.
4675 If so, then we can also infer a nonzero value range
4676 for the operand of the NOP_EXPR. */
4677 if (comp_code
== NE_EXPR
&& integer_zerop (value
))
4680 gimple def_stmt
= SSA_NAME_DEF_STMT (t
);
4682 while (is_gimple_assign (def_stmt
)
4683 && gimple_assign_rhs_code (def_stmt
) == NOP_EXPR
4685 (gimple_assign_rhs1 (def_stmt
)) == SSA_NAME
4687 (TREE_TYPE (gimple_assign_rhs1 (def_stmt
))))
4689 t
= gimple_assign_rhs1 (def_stmt
);
4690 def_stmt
= SSA_NAME_DEF_STMT (t
);
4692 /* Note we want to register the assert for the
4693 operand of the NOP_EXPR after SI, not after the
4695 if (! has_single_use (t
))
4697 register_new_assert_for (t
, t
, comp_code
, value
,
4704 /* If OP is used only once, namely in this STMT, don't
4705 bother creating an ASSERT_EXPR for it. Such an
4706 ASSERT_EXPR would do nothing but increase compile time. */
4707 if (!has_single_use (op
))
4709 register_new_assert_for (op
, op
, comp_code
, value
,
4717 /* Traverse all PHI nodes in BB marking used operands. */
4718 for (si
= gsi_start_phis (bb
); !gsi_end_p(si
); gsi_next (&si
))
4720 use_operand_p arg_p
;
4722 phi
= gsi_stmt (si
);
4724 FOR_EACH_PHI_ARG (arg_p
, phi
, i
, SSA_OP_USE
)
4726 tree arg
= USE_FROM_PTR (arg_p
);
4727 if (TREE_CODE (arg
) == SSA_NAME
)
4728 SET_BIT (live
, SSA_NAME_VERSION (arg
));
4735 /* Do an RPO walk over the function computing SSA name liveness
4736 on-the-fly and deciding on assert expressions to insert.
4737 Returns true if there are assert expressions to be inserted. */
4740 find_assert_locations (void)
4742 int *rpo
= XCNEWVEC (int, last_basic_block
+ NUM_FIXED_BLOCKS
);
4743 int *bb_rpo
= XCNEWVEC (int, last_basic_block
+ NUM_FIXED_BLOCKS
);
4744 int *last_rpo
= XCNEWVEC (int, last_basic_block
+ NUM_FIXED_BLOCKS
);
4748 live
= XCNEWVEC (sbitmap
, last_basic_block
+ NUM_FIXED_BLOCKS
);
4749 rpo_cnt
= pre_and_rev_post_order_compute (NULL
, rpo
, false);
4750 for (i
= 0; i
< rpo_cnt
; ++i
)
4753 need_asserts
= false;
4754 for (i
= rpo_cnt
-1; i
>= 0; --i
)
4756 basic_block bb
= BASIC_BLOCK (rpo
[i
]);
4762 live
[rpo
[i
]] = sbitmap_alloc (num_ssa_names
);
4763 sbitmap_zero (live
[rpo
[i
]]);
4766 /* Process BB and update the live information with uses in
4768 need_asserts
|= find_assert_locations_1 (bb
, live
[rpo
[i
]]);
4770 /* Merge liveness into the predecessor blocks and free it. */
4771 if (!sbitmap_empty_p (live
[rpo
[i
]]))
4774 FOR_EACH_EDGE (e
, ei
, bb
->preds
)
4776 int pred
= e
->src
->index
;
4777 if (e
->flags
& EDGE_DFS_BACK
)
4782 live
[pred
] = sbitmap_alloc (num_ssa_names
);
4783 sbitmap_zero (live
[pred
]);
4785 sbitmap_a_or_b (live
[pred
], live
[pred
], live
[rpo
[i
]]);
4787 if (bb_rpo
[pred
] < pred_rpo
)
4788 pred_rpo
= bb_rpo
[pred
];
4791 /* Record the RPO number of the last visited block that needs
4792 live information from this block. */
4793 last_rpo
[rpo
[i
]] = pred_rpo
;
4797 sbitmap_free (live
[rpo
[i
]]);
4798 live
[rpo
[i
]] = NULL
;
4801 /* We can free all successors live bitmaps if all their
4802 predecessors have been visited already. */
4803 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
4804 if (last_rpo
[e
->dest
->index
] == i
4805 && live
[e
->dest
->index
])
4807 sbitmap_free (live
[e
->dest
->index
]);
4808 live
[e
->dest
->index
] = NULL
;
4813 XDELETEVEC (bb_rpo
);
4814 XDELETEVEC (last_rpo
);
4815 for (i
= 0; i
< last_basic_block
+ NUM_FIXED_BLOCKS
; ++i
)
4817 sbitmap_free (live
[i
]);
4820 return need_asserts
;
4823 /* Create an ASSERT_EXPR for NAME and insert it in the location
4824 indicated by LOC. Return true if we made any edge insertions. */
4827 process_assert_insertions_for (tree name
, assert_locus_t loc
)
4829 /* Build the comparison expression NAME_i COMP_CODE VAL. */
4836 cond
= build2 (loc
->comp_code
, boolean_type_node
, loc
->expr
, loc
->val
);
4837 assert_stmt
= build_assert_expr_for (cond
, name
);
4840 /* We have been asked to insert the assertion on an edge. This
4841 is used only by COND_EXPR and SWITCH_EXPR assertions. */
4842 #if defined ENABLE_CHECKING
4843 gcc_assert (gimple_code (gsi_stmt (loc
->si
)) == GIMPLE_COND
4844 || gimple_code (gsi_stmt (loc
->si
)) == GIMPLE_SWITCH
);
4847 gsi_insert_on_edge (loc
->e
, assert_stmt
);
4851 /* Otherwise, we can insert right after LOC->SI iff the
4852 statement must not be the last statement in the block. */
4853 stmt
= gsi_stmt (loc
->si
);
4854 if (!stmt_ends_bb_p (stmt
))
4856 gsi_insert_after (&loc
->si
, assert_stmt
, GSI_SAME_STMT
);
4860 /* If STMT must be the last statement in BB, we can only insert new
4861 assertions on the non-abnormal edge out of BB. Note that since
4862 STMT is not control flow, there may only be one non-abnormal edge
4864 FOR_EACH_EDGE (e
, ei
, loc
->bb
->succs
)
4865 if (!(e
->flags
& EDGE_ABNORMAL
))
4867 gsi_insert_on_edge (e
, assert_stmt
);
4875 /* Process all the insertions registered for every name N_i registered
4876 in NEED_ASSERT_FOR. The list of assertions to be inserted are
4877 found in ASSERTS_FOR[i]. */
4880 process_assert_insertions (void)
4884 bool update_edges_p
= false;
4885 int num_asserts
= 0;
4887 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
4888 dump_all_asserts (dump_file
);
4890 EXECUTE_IF_SET_IN_BITMAP (need_assert_for
, 0, i
, bi
)
4892 assert_locus_t loc
= asserts_for
[i
];
4897 assert_locus_t next
= loc
->next
;
4898 update_edges_p
|= process_assert_insertions_for (ssa_name (i
), loc
);
4906 gsi_commit_edge_inserts ();
4908 statistics_counter_event (cfun
, "Number of ASSERT_EXPR expressions inserted",
4913 /* Traverse the flowgraph looking for conditional jumps to insert range
4914 expressions. These range expressions are meant to provide information
4915 to optimizations that need to reason in terms of value ranges. They
4916 will not be expanded into RTL. For instance, given:
4925 this pass will transform the code into:
4931 x = ASSERT_EXPR <x, x < y>
4936 y = ASSERT_EXPR <y, x <= y>
4940 The idea is that once copy and constant propagation have run, other
4941 optimizations will be able to determine what ranges of values can 'x'
4942 take in different paths of the code, simply by checking the reaching
4943 definition of 'x'. */
4946 insert_range_assertions (void)
4948 need_assert_for
= BITMAP_ALLOC (NULL
);
4949 asserts_for
= XCNEWVEC (assert_locus_t
, num_ssa_names
);
4951 calculate_dominance_info (CDI_DOMINATORS
);
4953 if (find_assert_locations ())
4955 process_assert_insertions ();
4956 update_ssa (TODO_update_ssa_no_phi
);
4959 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
4961 fprintf (dump_file
, "\nSSA form after inserting ASSERT_EXPRs\n");
4962 dump_function_to_file (current_function_decl
, dump_file
, dump_flags
);
4966 BITMAP_FREE (need_assert_for
);
4969 /* Checks one ARRAY_REF in REF, located at LOCUS. Ignores flexible arrays
4970 and "struct" hacks. If VRP can determine that the
4971 array subscript is a constant, check if it is outside valid
4972 range. If the array subscript is a RANGE, warn if it is
4973 non-overlapping with valid range.
4974 IGNORE_OFF_BY_ONE is true if the ARRAY_REF is inside a ADDR_EXPR. */
4977 check_array_ref (location_t location
, tree ref
, bool ignore_off_by_one
)
4979 value_range_t
* vr
= NULL
;
4980 tree low_sub
, up_sub
;
4981 tree low_bound
, up_bound
= array_ref_up_bound (ref
);
4983 low_sub
= up_sub
= TREE_OPERAND (ref
, 1);
4985 if (!up_bound
|| TREE_NO_WARNING (ref
)
4986 || TREE_CODE (up_bound
) != INTEGER_CST
4987 /* Can not check flexible arrays. */
4988 || (TYPE_SIZE (TREE_TYPE (ref
)) == NULL_TREE
4989 && TYPE_DOMAIN (TREE_TYPE (ref
)) != NULL_TREE
4990 && TYPE_MAX_VALUE (TYPE_DOMAIN (TREE_TYPE (ref
))) == NULL_TREE
)
4991 /* Accesses after the end of arrays of size 0 (gcc
4992 extension) and 1 are likely intentional ("struct
4994 || compare_tree_int (up_bound
, 1) <= 0)
4997 low_bound
= array_ref_low_bound (ref
);
4999 if (TREE_CODE (low_sub
) == SSA_NAME
)
5001 vr
= get_value_range (low_sub
);
5002 if (vr
->type
== VR_RANGE
|| vr
->type
== VR_ANTI_RANGE
)
5004 low_sub
= vr
->type
== VR_RANGE
? vr
->max
: vr
->min
;
5005 up_sub
= vr
->type
== VR_RANGE
? vr
->min
: vr
->max
;
5009 if (vr
&& vr
->type
== VR_ANTI_RANGE
)
5011 if (TREE_CODE (up_sub
) == INTEGER_CST
5012 && tree_int_cst_lt (up_bound
, up_sub
)
5013 && TREE_CODE (low_sub
) == INTEGER_CST
5014 && tree_int_cst_lt (low_sub
, low_bound
))
5016 warning_at (location
, OPT_Warray_bounds
,
5017 "array subscript is outside array bounds");
5018 TREE_NO_WARNING (ref
) = 1;
5021 else if (TREE_CODE (up_sub
) == INTEGER_CST
5022 && tree_int_cst_lt (up_bound
, up_sub
)
5023 && !tree_int_cst_equal (up_bound
, up_sub
)
5024 && (!ignore_off_by_one
5025 || !tree_int_cst_equal (int_const_binop (PLUS_EXPR
,
5031 warning_at (location
, OPT_Warray_bounds
,
5032 "array subscript is above array bounds");
5033 TREE_NO_WARNING (ref
) = 1;
5035 else if (TREE_CODE (low_sub
) == INTEGER_CST
5036 && tree_int_cst_lt (low_sub
, low_bound
))
5038 warning_at (location
, OPT_Warray_bounds
,
5039 "array subscript is below array bounds");
5040 TREE_NO_WARNING (ref
) = 1;
5044 /* Searches if the expr T, located at LOCATION computes
5045 address of an ARRAY_REF, and call check_array_ref on it. */
5048 search_for_addr_array (tree t
, location_t location
)
5050 while (TREE_CODE (t
) == SSA_NAME
)
5052 gimple g
= SSA_NAME_DEF_STMT (t
);
5054 if (gimple_code (g
) != GIMPLE_ASSIGN
)
5057 if (get_gimple_rhs_class (gimple_assign_rhs_code (g
))
5058 != GIMPLE_SINGLE_RHS
)
5061 t
= gimple_assign_rhs1 (g
);
5065 /* We are only interested in addresses of ARRAY_REF's. */
5066 if (TREE_CODE (t
) != ADDR_EXPR
)
5069 /* Check each ARRAY_REFs in the reference chain. */
5072 if (TREE_CODE (t
) == ARRAY_REF
)
5073 check_array_ref (location
, t
, true /*ignore_off_by_one*/);
5075 t
= TREE_OPERAND (t
, 0);
5077 while (handled_component_p (t
));
5080 /* walk_tree() callback that checks if *TP is
5081 an ARRAY_REF inside an ADDR_EXPR (in which an array
5082 subscript one outside the valid range is allowed). Call
5083 check_array_ref for each ARRAY_REF found. The location is
5087 check_array_bounds (tree
*tp
, int *walk_subtree
, void *data
)
5090 struct walk_stmt_info
*wi
= (struct walk_stmt_info
*) data
;
5091 location_t location
;
5093 if (EXPR_HAS_LOCATION (t
))
5094 location
= EXPR_LOCATION (t
);
5097 location_t
*locp
= (location_t
*) wi
->info
;
5101 *walk_subtree
= TRUE
;
5103 if (TREE_CODE (t
) == ARRAY_REF
)
5104 check_array_ref (location
, t
, false /*ignore_off_by_one*/);
5106 if (TREE_CODE (t
) == INDIRECT_REF
5107 || (TREE_CODE (t
) == RETURN_EXPR
&& TREE_OPERAND (t
, 0)))
5108 search_for_addr_array (TREE_OPERAND (t
, 0), location
);
5110 if (TREE_CODE (t
) == ADDR_EXPR
)
5111 *walk_subtree
= FALSE
;
5116 /* Walk over all statements of all reachable BBs and call check_array_bounds
5120 check_all_array_refs (void)
5123 gimple_stmt_iterator si
;
5127 /* Skip bb's that are clearly unreachable. */
5128 if (single_pred_p (bb
))
5131 bool reachable
= true;
5133 edge e
= EDGE_PRED (bb
, 0);
5134 basic_block pred_bb
= e
->src
;
5137 for (i
= 0; VEC_iterate (edge
, to_remove_edges
, i
, e2
); ++i
)
5147 if (!gsi_end_p (gsi_last_bb (pred_bb
)))
5148 ls
= gsi_stmt (gsi_last_bb (pred_bb
));
5150 if (ls
&& gimple_code (ls
) == GIMPLE_COND
5151 && ((gimple_cond_false_p (ls
)
5152 && (EDGE_PRED (bb
, 0)->flags
& EDGE_TRUE_VALUE
))
5153 || (gimple_cond_true_p (ls
)
5154 && (EDGE_PRED (bb
, 0)->flags
& EDGE_FALSE_VALUE
))))
5157 for (si
= gsi_start_bb (bb
); !gsi_end_p (si
); gsi_next (&si
))
5159 gimple stmt
= gsi_stmt (si
);
5160 struct walk_stmt_info wi
;
5161 if (!gimple_has_location (stmt
))
5164 if (is_gimple_call (stmt
))
5167 size_t n
= gimple_call_num_args (stmt
);
5168 for (i
= 0; i
< n
; i
++)
5170 tree arg
= gimple_call_arg (stmt
, i
);
5171 search_for_addr_array (arg
, gimple_location (stmt
));
5176 memset (&wi
, 0, sizeof (wi
));
5177 wi
.info
= CONST_CAST (void *, (const void *)
5178 gimple_location_ptr (stmt
));
5180 walk_gimple_op (gsi_stmt (si
),
5188 /* Convert range assertion expressions into the implied copies and
5189 copy propagate away the copies. Doing the trivial copy propagation
5190 here avoids the need to run the full copy propagation pass after
5193 FIXME, this will eventually lead to copy propagation removing the
5194 names that had useful range information attached to them. For
5195 instance, if we had the assertion N_i = ASSERT_EXPR <N_j, N_j > 3>,
5196 then N_i will have the range [3, +INF].
5198 However, by converting the assertion into the implied copy
5199 operation N_i = N_j, we will then copy-propagate N_j into the uses
5200 of N_i and lose the range information. We may want to hold on to
5201 ASSERT_EXPRs a little while longer as the ranges could be used in
5202 things like jump threading.
5204 The problem with keeping ASSERT_EXPRs around is that passes after
5205 VRP need to handle them appropriately.
5207 Another approach would be to make the range information a first
5208 class property of the SSA_NAME so that it can be queried from
5209 any pass. This is made somewhat more complex by the need for
5210 multiple ranges to be associated with one SSA_NAME. */
5213 remove_range_assertions (void)
5216 gimple_stmt_iterator si
;
5218 /* Note that the BSI iterator bump happens at the bottom of the
5219 loop and no bump is necessary if we're removing the statement
5220 referenced by the current BSI. */
5222 for (si
= gsi_start_bb (bb
); !gsi_end_p (si
);)
5224 gimple stmt
= gsi_stmt (si
);
5227 if (is_gimple_assign (stmt
)
5228 && gimple_assign_rhs_code (stmt
) == ASSERT_EXPR
)
5230 tree rhs
= gimple_assign_rhs1 (stmt
);
5232 tree cond
= fold (ASSERT_EXPR_COND (rhs
));
5233 use_operand_p use_p
;
5234 imm_use_iterator iter
;
5236 gcc_assert (cond
!= boolean_false_node
);
5238 /* Propagate the RHS into every use of the LHS. */
5239 var
= ASSERT_EXPR_VAR (rhs
);
5240 FOR_EACH_IMM_USE_STMT (use_stmt
, iter
,
5241 gimple_assign_lhs (stmt
))
5242 FOR_EACH_IMM_USE_ON_STMT (use_p
, iter
)
5244 SET_USE (use_p
, var
);
5245 gcc_assert (TREE_CODE (var
) == SSA_NAME
);
5248 /* And finally, remove the copy, it is not needed. */
5249 gsi_remove (&si
, true);
5250 release_defs (stmt
);
5258 /* Return true if STMT is interesting for VRP. */
5261 stmt_interesting_for_vrp (gimple stmt
)
5263 if (gimple_code (stmt
) == GIMPLE_PHI
5264 && is_gimple_reg (gimple_phi_result (stmt
))
5265 && (INTEGRAL_TYPE_P (TREE_TYPE (gimple_phi_result (stmt
)))
5266 || POINTER_TYPE_P (TREE_TYPE (gimple_phi_result (stmt
)))))
5268 else if (is_gimple_assign (stmt
) || is_gimple_call (stmt
))
5270 tree lhs
= gimple_get_lhs (stmt
);
5272 /* In general, assignments with virtual operands are not useful
5273 for deriving ranges, with the obvious exception of calls to
5274 builtin functions. */
5275 if (lhs
&& TREE_CODE (lhs
) == SSA_NAME
5276 && (INTEGRAL_TYPE_P (TREE_TYPE (lhs
))
5277 || POINTER_TYPE_P (TREE_TYPE (lhs
)))
5278 && ((is_gimple_call (stmt
)
5279 && gimple_call_fndecl (stmt
) != NULL_TREE
5280 && DECL_IS_BUILTIN (gimple_call_fndecl (stmt
)))
5281 || !gimple_vuse (stmt
)))
5284 else if (gimple_code (stmt
) == GIMPLE_COND
5285 || gimple_code (stmt
) == GIMPLE_SWITCH
)
5292 /* Initialize local data structures for VRP. */
5295 vrp_initialize (void)
5299 vr_value
= XCNEWVEC (value_range_t
*, num_ssa_names
);
5300 vr_phi_edge_counts
= XCNEWVEC (int, num_ssa_names
);
5304 gimple_stmt_iterator si
;
5306 for (si
= gsi_start_phis (bb
); !gsi_end_p (si
); gsi_next (&si
))
5308 gimple phi
= gsi_stmt (si
);
5309 if (!stmt_interesting_for_vrp (phi
))
5311 tree lhs
= PHI_RESULT (phi
);
5312 set_value_range_to_varying (get_value_range (lhs
));
5313 prop_set_simulate_again (phi
, false);
5316 prop_set_simulate_again (phi
, true);
5319 for (si
= gsi_start_bb (bb
); !gsi_end_p (si
); gsi_next (&si
))
5321 gimple stmt
= gsi_stmt (si
);
5323 /* If the statement is a control insn, then we do not
5324 want to avoid simulating the statement once. Failure
5325 to do so means that those edges will never get added. */
5326 if (stmt_ends_bb_p (stmt
))
5327 prop_set_simulate_again (stmt
, true);
5328 else if (!stmt_interesting_for_vrp (stmt
))
5332 FOR_EACH_SSA_TREE_OPERAND (def
, stmt
, i
, SSA_OP_DEF
)
5333 set_value_range_to_varying (get_value_range (def
));
5334 prop_set_simulate_again (stmt
, false);
5337 prop_set_simulate_again (stmt
, true);
5343 /* Visit assignment STMT. If it produces an interesting range, record
5344 the SSA name in *OUTPUT_P. */
5346 static enum ssa_prop_result
5347 vrp_visit_assignment_or_call (gimple stmt
, tree
*output_p
)
5351 enum gimple_code code
= gimple_code (stmt
);
5352 lhs
= gimple_get_lhs (stmt
);
5354 /* We only keep track of ranges in integral and pointer types. */
5355 if (TREE_CODE (lhs
) == SSA_NAME
5356 && ((INTEGRAL_TYPE_P (TREE_TYPE (lhs
))
5357 /* It is valid to have NULL MIN/MAX values on a type. See
5358 build_range_type. */
5359 && TYPE_MIN_VALUE (TREE_TYPE (lhs
))
5360 && TYPE_MAX_VALUE (TREE_TYPE (lhs
)))
5361 || POINTER_TYPE_P (TREE_TYPE (lhs
))))
5364 value_range_t new_vr
= { VR_UNDEFINED
, NULL_TREE
, NULL_TREE
, NULL
};
5366 if (code
== GIMPLE_CALL
)
5367 extract_range_basic (&new_vr
, stmt
);
5369 extract_range_from_assignment (&new_vr
, stmt
);
5371 /* If STMT is inside a loop, we may be able to know something
5372 else about the range of LHS by examining scalar evolution
5374 if (current_loops
&& (l
= loop_containing_stmt (stmt
)))
5375 adjust_range_with_scev (&new_vr
, l
, stmt
, lhs
);
5377 if (update_value_range (lhs
, &new_vr
))
5381 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
5383 fprintf (dump_file
, "Found new range for ");
5384 print_generic_expr (dump_file
, lhs
, 0);
5385 fprintf (dump_file
, ": ");
5386 dump_value_range (dump_file
, &new_vr
);
5387 fprintf (dump_file
, "\n\n");
5390 if (new_vr
.type
== VR_VARYING
)
5391 return SSA_PROP_VARYING
;
5393 return SSA_PROP_INTERESTING
;
5396 return SSA_PROP_NOT_INTERESTING
;
5399 /* Every other statement produces no useful ranges. */
5400 FOR_EACH_SSA_TREE_OPERAND (def
, stmt
, iter
, SSA_OP_DEF
)
5401 set_value_range_to_varying (get_value_range (def
));
5403 return SSA_PROP_VARYING
;
5406 /* Helper that gets the value range of the SSA_NAME with version I
5407 or a symbolic range containing the SSA_NAME only if the value range
5408 is varying or undefined. */
5410 static inline value_range_t
5411 get_vr_for_comparison (int i
)
5413 value_range_t vr
= *(vr_value
[i
]);
5415 /* If name N_i does not have a valid range, use N_i as its own
5416 range. This allows us to compare against names that may
5417 have N_i in their ranges. */
5418 if (vr
.type
== VR_VARYING
|| vr
.type
== VR_UNDEFINED
)
5421 vr
.min
= ssa_name (i
);
5422 vr
.max
= ssa_name (i
);
5428 /* Compare all the value ranges for names equivalent to VAR with VAL
5429 using comparison code COMP. Return the same value returned by
5430 compare_range_with_value, including the setting of
5431 *STRICT_OVERFLOW_P. */
5434 compare_name_with_value (enum tree_code comp
, tree var
, tree val
,
5435 bool *strict_overflow_p
)
5441 int used_strict_overflow
;
5443 value_range_t equiv_vr
;
5445 /* Get the set of equivalences for VAR. */
5446 e
= get_value_range (var
)->equiv
;
5448 /* Start at -1. Set it to 0 if we do a comparison without relying
5449 on overflow, or 1 if all comparisons rely on overflow. */
5450 used_strict_overflow
= -1;
5452 /* Compare vars' value range with val. */
5453 equiv_vr
= get_vr_for_comparison (SSA_NAME_VERSION (var
));
5455 retval
= compare_range_with_value (comp
, &equiv_vr
, val
, &sop
);
5457 used_strict_overflow
= sop
? 1 : 0;
5459 /* If the equiv set is empty we have done all work we need to do. */
5463 && used_strict_overflow
> 0)
5464 *strict_overflow_p
= true;
5468 EXECUTE_IF_SET_IN_BITMAP (e
, 0, i
, bi
)
5470 equiv_vr
= get_vr_for_comparison (i
);
5472 t
= compare_range_with_value (comp
, &equiv_vr
, val
, &sop
);
5475 /* If we get different answers from different members
5476 of the equivalence set this check must be in a dead
5477 code region. Folding it to a trap representation
5478 would be correct here. For now just return don't-know. */
5488 used_strict_overflow
= 0;
5489 else if (used_strict_overflow
< 0)
5490 used_strict_overflow
= 1;
5495 && used_strict_overflow
> 0)
5496 *strict_overflow_p
= true;
5502 /* Given a comparison code COMP and names N1 and N2, compare all the
5503 ranges equivalent to N1 against all the ranges equivalent to N2
5504 to determine the value of N1 COMP N2. Return the same value
5505 returned by compare_ranges. Set *STRICT_OVERFLOW_P to indicate
5506 whether we relied on an overflow infinity in the comparison. */
5510 compare_names (enum tree_code comp
, tree n1
, tree n2
,
5511 bool *strict_overflow_p
)
5515 bitmap_iterator bi1
, bi2
;
5517 int used_strict_overflow
;
5518 static bitmap_obstack
*s_obstack
= NULL
;
5519 static bitmap s_e1
= NULL
, s_e2
= NULL
;
5521 /* Compare the ranges of every name equivalent to N1 against the
5522 ranges of every name equivalent to N2. */
5523 e1
= get_value_range (n1
)->equiv
;
5524 e2
= get_value_range (n2
)->equiv
;
5526 /* Use the fake bitmaps if e1 or e2 are not available. */
5527 if (s_obstack
== NULL
)
5529 s_obstack
= XNEW (bitmap_obstack
);
5530 bitmap_obstack_initialize (s_obstack
);
5531 s_e1
= BITMAP_ALLOC (s_obstack
);
5532 s_e2
= BITMAP_ALLOC (s_obstack
);
5539 /* Add N1 and N2 to their own set of equivalences to avoid
5540 duplicating the body of the loop just to check N1 and N2
5542 bitmap_set_bit (e1
, SSA_NAME_VERSION (n1
));
5543 bitmap_set_bit (e2
, SSA_NAME_VERSION (n2
));
5545 /* If the equivalence sets have a common intersection, then the two
5546 names can be compared without checking their ranges. */
5547 if (bitmap_intersect_p (e1
, e2
))
5549 bitmap_clear_bit (e1
, SSA_NAME_VERSION (n1
));
5550 bitmap_clear_bit (e2
, SSA_NAME_VERSION (n2
));
5552 return (comp
== EQ_EXPR
|| comp
== GE_EXPR
|| comp
== LE_EXPR
)
5554 : boolean_false_node
;
5557 /* Start at -1. Set it to 0 if we do a comparison without relying
5558 on overflow, or 1 if all comparisons rely on overflow. */
5559 used_strict_overflow
= -1;
5561 /* Otherwise, compare all the equivalent ranges. First, add N1 and
5562 N2 to their own set of equivalences to avoid duplicating the body
5563 of the loop just to check N1 and N2 ranges. */
5564 EXECUTE_IF_SET_IN_BITMAP (e1
, 0, i1
, bi1
)
5566 value_range_t vr1
= get_vr_for_comparison (i1
);
5568 t
= retval
= NULL_TREE
;
5569 EXECUTE_IF_SET_IN_BITMAP (e2
, 0, i2
, bi2
)
5573 value_range_t vr2
= get_vr_for_comparison (i2
);
5575 t
= compare_ranges (comp
, &vr1
, &vr2
, &sop
);
5578 /* If we get different answers from different members
5579 of the equivalence set this check must be in a dead
5580 code region. Folding it to a trap representation
5581 would be correct here. For now just return don't-know. */
5585 bitmap_clear_bit (e1
, SSA_NAME_VERSION (n1
));
5586 bitmap_clear_bit (e2
, SSA_NAME_VERSION (n2
));
5592 used_strict_overflow
= 0;
5593 else if (used_strict_overflow
< 0)
5594 used_strict_overflow
= 1;
5600 bitmap_clear_bit (e1
, SSA_NAME_VERSION (n1
));
5601 bitmap_clear_bit (e2
, SSA_NAME_VERSION (n2
));
5602 if (used_strict_overflow
> 0)
5603 *strict_overflow_p
= true;
5608 /* None of the equivalent ranges are useful in computing this
5610 bitmap_clear_bit (e1
, SSA_NAME_VERSION (n1
));
5611 bitmap_clear_bit (e2
, SSA_NAME_VERSION (n2
));
5615 /* Helper function for vrp_evaluate_conditional_warnv. */
5618 vrp_evaluate_conditional_warnv_with_ops_using_ranges (enum tree_code code
,
5620 bool * strict_overflow_p
)
5622 value_range_t
*vr0
, *vr1
;
5624 vr0
= (TREE_CODE (op0
) == SSA_NAME
) ? get_value_range (op0
) : NULL
;
5625 vr1
= (TREE_CODE (op1
) == SSA_NAME
) ? get_value_range (op1
) : NULL
;
5628 return compare_ranges (code
, vr0
, vr1
, strict_overflow_p
);
5629 else if (vr0
&& vr1
== NULL
)
5630 return compare_range_with_value (code
, vr0
, op1
, strict_overflow_p
);
5631 else if (vr0
== NULL
&& vr1
)
5632 return (compare_range_with_value
5633 (swap_tree_comparison (code
), vr1
, op0
, strict_overflow_p
));
5637 /* Helper function for vrp_evaluate_conditional_warnv. */
5640 vrp_evaluate_conditional_warnv_with_ops (enum tree_code code
, tree op0
,
5641 tree op1
, bool use_equiv_p
,
5642 bool *strict_overflow_p
, bool *only_ranges
)
5646 *only_ranges
= true;
5648 /* We only deal with integral and pointer types. */
5649 if (!INTEGRAL_TYPE_P (TREE_TYPE (op0
))
5650 && !POINTER_TYPE_P (TREE_TYPE (op0
)))
5656 && (ret
= vrp_evaluate_conditional_warnv_with_ops_using_ranges
5657 (code
, op0
, op1
, strict_overflow_p
)))
5659 *only_ranges
= false;
5660 if (TREE_CODE (op0
) == SSA_NAME
&& TREE_CODE (op1
) == SSA_NAME
)
5661 return compare_names (code
, op0
, op1
, strict_overflow_p
);
5662 else if (TREE_CODE (op0
) == SSA_NAME
)
5663 return compare_name_with_value (code
, op0
, op1
, strict_overflow_p
);
5664 else if (TREE_CODE (op1
) == SSA_NAME
)
5665 return (compare_name_with_value
5666 (swap_tree_comparison (code
), op1
, op0
, strict_overflow_p
));
5669 return vrp_evaluate_conditional_warnv_with_ops_using_ranges (code
, op0
, op1
,
5674 /* Given (CODE OP0 OP1) within STMT, try to simplify it based on value range
5675 information. Return NULL if the conditional can not be evaluated.
5676 The ranges of all the names equivalent with the operands in COND
5677 will be used when trying to compute the value. If the result is
5678 based on undefined signed overflow, issue a warning if
5682 vrp_evaluate_conditional (enum tree_code code
, tree op0
, tree op1
, gimple stmt
)
5688 /* Some passes and foldings leak constants with overflow flag set
5689 into the IL. Avoid doing wrong things with these and bail out. */
5690 if ((TREE_CODE (op0
) == INTEGER_CST
5691 && TREE_OVERFLOW (op0
))
5692 || (TREE_CODE (op1
) == INTEGER_CST
5693 && TREE_OVERFLOW (op1
)))
5697 ret
= vrp_evaluate_conditional_warnv_with_ops (code
, op0
, op1
, true, &sop
,
5702 enum warn_strict_overflow_code wc
;
5703 const char* warnmsg
;
5705 if (is_gimple_min_invariant (ret
))
5707 wc
= WARN_STRICT_OVERFLOW_CONDITIONAL
;
5708 warnmsg
= G_("assuming signed overflow does not occur when "
5709 "simplifying conditional to constant");
5713 wc
= WARN_STRICT_OVERFLOW_COMPARISON
;
5714 warnmsg
= G_("assuming signed overflow does not occur when "
5715 "simplifying conditional");
5718 if (issue_strict_overflow_warning (wc
))
5720 location_t location
;
5722 if (!gimple_has_location (stmt
))
5723 location
= input_location
;
5725 location
= gimple_location (stmt
);
5726 warning_at (location
, OPT_Wstrict_overflow
, "%s", warnmsg
);
5730 if (warn_type_limits
5731 && ret
&& only_ranges
5732 && TREE_CODE_CLASS (code
) == tcc_comparison
5733 && TREE_CODE (op0
) == SSA_NAME
)
5735 /* If the comparison is being folded and the operand on the LHS
5736 is being compared against a constant value that is outside of
5737 the natural range of OP0's type, then the predicate will
5738 always fold regardless of the value of OP0. If -Wtype-limits
5739 was specified, emit a warning. */
5740 tree type
= TREE_TYPE (op0
);
5741 value_range_t
*vr0
= get_value_range (op0
);
5743 if (vr0
->type
!= VR_VARYING
5744 && INTEGRAL_TYPE_P (type
)
5745 && vrp_val_is_min (vr0
->min
)
5746 && vrp_val_is_max (vr0
->max
)
5747 && is_gimple_min_invariant (op1
))
5749 location_t location
;
5751 if (!gimple_has_location (stmt
))
5752 location
= input_location
;
5754 location
= gimple_location (stmt
);
5756 warning_at (location
, OPT_Wtype_limits
,
5758 ? G_("comparison always false "
5759 "due to limited range of data type")
5760 : G_("comparison always true "
5761 "due to limited range of data type"));
5769 /* Visit conditional statement STMT. If we can determine which edge
5770 will be taken out of STMT's basic block, record it in
5771 *TAKEN_EDGE_P and return SSA_PROP_INTERESTING. Otherwise, return
5772 SSA_PROP_VARYING. */
5774 static enum ssa_prop_result
5775 vrp_visit_cond_stmt (gimple stmt
, edge
*taken_edge_p
)
5780 *taken_edge_p
= NULL
;
5782 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
5787 fprintf (dump_file
, "\nVisiting conditional with predicate: ");
5788 print_gimple_stmt (dump_file
, stmt
, 0, 0);
5789 fprintf (dump_file
, "\nWith known ranges\n");
5791 FOR_EACH_SSA_TREE_OPERAND (use
, stmt
, i
, SSA_OP_USE
)
5793 fprintf (dump_file
, "\t");
5794 print_generic_expr (dump_file
, use
, 0);
5795 fprintf (dump_file
, ": ");
5796 dump_value_range (dump_file
, vr_value
[SSA_NAME_VERSION (use
)]);
5799 fprintf (dump_file
, "\n");
5802 /* Compute the value of the predicate COND by checking the known
5803 ranges of each of its operands.
5805 Note that we cannot evaluate all the equivalent ranges here
5806 because those ranges may not yet be final and with the current
5807 propagation strategy, we cannot determine when the value ranges
5808 of the names in the equivalence set have changed.
5810 For instance, given the following code fragment
5814 i_14 = ASSERT_EXPR <i_5, i_5 != 0>
5818 Assume that on the first visit to i_14, i_5 has the temporary
5819 range [8, 8] because the second argument to the PHI function is
5820 not yet executable. We derive the range ~[0, 0] for i_14 and the
5821 equivalence set { i_5 }. So, when we visit 'if (i_14 == 1)' for
5822 the first time, since i_14 is equivalent to the range [8, 8], we
5823 determine that the predicate is always false.
5825 On the next round of propagation, i_13 is determined to be
5826 VARYING, which causes i_5 to drop down to VARYING. So, another
5827 visit to i_14 is scheduled. In this second visit, we compute the
5828 exact same range and equivalence set for i_14, namely ~[0, 0] and
5829 { i_5 }. But we did not have the previous range for i_5
5830 registered, so vrp_visit_assignment thinks that the range for
5831 i_14 has not changed. Therefore, the predicate 'if (i_14 == 1)'
5832 is not visited again, which stops propagation from visiting
5833 statements in the THEN clause of that if().
5835 To properly fix this we would need to keep the previous range
5836 value for the names in the equivalence set. This way we would've
5837 discovered that from one visit to the other i_5 changed from
5838 range [8, 8] to VR_VARYING.
5840 However, fixing this apparent limitation may not be worth the
5841 additional checking. Testing on several code bases (GCC, DLV,
5842 MICO, TRAMP3D and SPEC2000) showed that doing this results in
5843 4 more predicates folded in SPEC. */
5846 val
= vrp_evaluate_conditional_warnv_with_ops (gimple_cond_code (stmt
),
5847 gimple_cond_lhs (stmt
),
5848 gimple_cond_rhs (stmt
),
5853 *taken_edge_p
= find_taken_edge (gimple_bb (stmt
), val
);
5856 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
5858 "\nIgnoring predicate evaluation because "
5859 "it assumes that signed overflow is undefined");
5864 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
5866 fprintf (dump_file
, "\nPredicate evaluates to: ");
5867 if (val
== NULL_TREE
)
5868 fprintf (dump_file
, "DON'T KNOW\n");
5870 print_generic_stmt (dump_file
, val
, 0);
5873 return (*taken_edge_p
) ? SSA_PROP_INTERESTING
: SSA_PROP_VARYING
;
5876 /* Searches the case label vector VEC for the index *IDX of the CASE_LABEL
5877 that includes the value VAL. The search is restricted to the range
5878 [START_IDX, n - 1] where n is the size of VEC.
5880 If there is a CASE_LABEL for VAL, its index is placed in IDX and true is
5883 If there is no CASE_LABEL for VAL and there is one that is larger than VAL,
5884 it is placed in IDX and false is returned.
5886 If VAL is larger than any CASE_LABEL, n is placed on IDX and false is
5890 find_case_label_index (gimple stmt
, size_t start_idx
, tree val
, size_t *idx
)
5892 size_t n
= gimple_switch_num_labels (stmt
);
5895 /* Find case label for minimum of the value range or the next one.
5896 At each iteration we are searching in [low, high - 1]. */
5898 for (low
= start_idx
, high
= n
; high
!= low
; )
5902 /* Note that i != high, so we never ask for n. */
5903 size_t i
= (high
+ low
) / 2;
5904 t
= gimple_switch_label (stmt
, i
);
5906 /* Cache the result of comparing CASE_LOW and val. */
5907 cmp
= tree_int_cst_compare (CASE_LOW (t
), val
);
5911 /* Ranges cannot be empty. */
5920 if (CASE_HIGH (t
) != NULL
5921 && tree_int_cst_compare (CASE_HIGH (t
), val
) >= 0)
5933 /* Searches the case label vector VEC for the range of CASE_LABELs that is used
5934 for values between MIN and MAX. The first index is placed in MIN_IDX. The
5935 last index is placed in MAX_IDX. If the range of CASE_LABELs is empty
5936 then MAX_IDX < MIN_IDX.
5937 Returns true if the default label is not needed. */
5940 find_case_label_range (gimple stmt
, tree min
, tree max
, size_t *min_idx
,
5944 bool min_take_default
= !find_case_label_index (stmt
, 1, min
, &i
);
5945 bool max_take_default
= !find_case_label_index (stmt
, i
, max
, &j
);
5949 && max_take_default
)
5951 /* Only the default case label reached.
5952 Return an empty range. */
5959 bool take_default
= min_take_default
|| max_take_default
;
5963 if (max_take_default
)
5966 /* If the case label range is continuous, we do not need
5967 the default case label. Verify that. */
5968 high
= CASE_LOW (gimple_switch_label (stmt
, i
));
5969 if (CASE_HIGH (gimple_switch_label (stmt
, i
)))
5970 high
= CASE_HIGH (gimple_switch_label (stmt
, i
));
5971 for (k
= i
+ 1; k
<= j
; ++k
)
5973 low
= CASE_LOW (gimple_switch_label (stmt
, k
));
5974 if (!integer_onep (int_const_binop (MINUS_EXPR
, low
, high
, 0)))
5976 take_default
= true;
5980 if (CASE_HIGH (gimple_switch_label (stmt
, k
)))
5981 high
= CASE_HIGH (gimple_switch_label (stmt
, k
));
5986 return !take_default
;
5990 /* Visit switch statement STMT. If we can determine which edge
5991 will be taken out of STMT's basic block, record it in
5992 *TAKEN_EDGE_P and return SSA_PROP_INTERESTING. Otherwise, return
5993 SSA_PROP_VARYING. */
5995 static enum ssa_prop_result
5996 vrp_visit_switch_stmt (gimple stmt
, edge
*taken_edge_p
)
6000 size_t i
= 0, j
= 0, n
;
6003 *taken_edge_p
= NULL
;
6004 op
= gimple_switch_index (stmt
);
6005 if (TREE_CODE (op
) != SSA_NAME
)
6006 return SSA_PROP_VARYING
;
6008 vr
= get_value_range (op
);
6009 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
6011 fprintf (dump_file
, "\nVisiting switch expression with operand ");
6012 print_generic_expr (dump_file
, op
, 0);
6013 fprintf (dump_file
, " with known range ");
6014 dump_value_range (dump_file
, vr
);
6015 fprintf (dump_file
, "\n");
6018 if (vr
->type
!= VR_RANGE
6019 || symbolic_range_p (vr
))
6020 return SSA_PROP_VARYING
;
6022 /* Find the single edge that is taken from the switch expression. */
6023 n
= gimple_switch_num_labels (stmt
);
6025 take_default
= !find_case_label_range (stmt
, vr
->min
, vr
->max
, &i
, &j
);
6027 /* Check if the range spans no CASE_LABEL. If so, we only reach the default
6031 gcc_assert (take_default
);
6032 val
= gimple_switch_default_label (stmt
);
6036 /* Check if labels with index i to j and maybe the default label
6037 are all reaching the same label. */
6039 val
= gimple_switch_label (stmt
, i
);
6041 && CASE_LABEL (gimple_switch_default_label (stmt
))
6042 != CASE_LABEL (val
))
6044 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
6045 fprintf (dump_file
, " not a single destination for this "
6047 return SSA_PROP_VARYING
;
6049 for (++i
; i
<= j
; ++i
)
6051 if (CASE_LABEL (gimple_switch_label (stmt
, i
)) != CASE_LABEL (val
))
6053 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
6054 fprintf (dump_file
, " not a single destination for this "
6056 return SSA_PROP_VARYING
;
6061 *taken_edge_p
= find_edge (gimple_bb (stmt
),
6062 label_to_block (CASE_LABEL (val
)));
6064 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
6066 fprintf (dump_file
, " will take edge to ");
6067 print_generic_stmt (dump_file
, CASE_LABEL (val
), 0);
6070 return SSA_PROP_INTERESTING
;
6074 /* Evaluate statement STMT. If the statement produces a useful range,
6075 return SSA_PROP_INTERESTING and record the SSA name with the
6076 interesting range into *OUTPUT_P.
6078 If STMT is a conditional branch and we can determine its truth
6079 value, the taken edge is recorded in *TAKEN_EDGE_P.
6081 If STMT produces a varying value, return SSA_PROP_VARYING. */
6083 static enum ssa_prop_result
6084 vrp_visit_stmt (gimple stmt
, edge
*taken_edge_p
, tree
*output_p
)
6089 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
6091 fprintf (dump_file
, "\nVisiting statement:\n");
6092 print_gimple_stmt (dump_file
, stmt
, 0, dump_flags
);
6093 fprintf (dump_file
, "\n");
6096 if (!stmt_interesting_for_vrp (stmt
))
6097 gcc_assert (stmt_ends_bb_p (stmt
));
6098 else if (is_gimple_assign (stmt
) || is_gimple_call (stmt
))
6100 /* In general, assignments with virtual operands are not useful
6101 for deriving ranges, with the obvious exception of calls to
6102 builtin functions. */
6104 if ((is_gimple_call (stmt
)
6105 && gimple_call_fndecl (stmt
) != NULL_TREE
6106 && DECL_IS_BUILTIN (gimple_call_fndecl (stmt
)))
6107 || !gimple_vuse (stmt
))
6108 return vrp_visit_assignment_or_call (stmt
, output_p
);
6110 else if (gimple_code (stmt
) == GIMPLE_COND
)
6111 return vrp_visit_cond_stmt (stmt
, taken_edge_p
);
6112 else if (gimple_code (stmt
) == GIMPLE_SWITCH
)
6113 return vrp_visit_switch_stmt (stmt
, taken_edge_p
);
6115 /* All other statements produce nothing of interest for VRP, so mark
6116 their outputs varying and prevent further simulation. */
6117 FOR_EACH_SSA_TREE_OPERAND (def
, stmt
, iter
, SSA_OP_DEF
)
6118 set_value_range_to_varying (get_value_range (def
));
6120 return SSA_PROP_VARYING
;
6124 /* Meet operation for value ranges. Given two value ranges VR0 and
6125 VR1, store in VR0 a range that contains both VR0 and VR1. This
6126 may not be the smallest possible such range. */
6129 vrp_meet (value_range_t
*vr0
, value_range_t
*vr1
)
6131 if (vr0
->type
== VR_UNDEFINED
)
6133 copy_value_range (vr0
, vr1
);
6137 if (vr1
->type
== VR_UNDEFINED
)
6139 /* Nothing to do. VR0 already has the resulting range. */
6143 if (vr0
->type
== VR_VARYING
)
6145 /* Nothing to do. VR0 already has the resulting range. */
6149 if (vr1
->type
== VR_VARYING
)
6151 set_value_range_to_varying (vr0
);
6155 if (vr0
->type
== VR_RANGE
&& vr1
->type
== VR_RANGE
)
6160 /* Compute the convex hull of the ranges. The lower limit of
6161 the new range is the minimum of the two ranges. If they
6162 cannot be compared, then give up. */
6163 cmp
= compare_values (vr0
->min
, vr1
->min
);
6164 if (cmp
== 0 || cmp
== 1)
6171 /* Similarly, the upper limit of the new range is the maximum
6172 of the two ranges. If they cannot be compared, then
6174 cmp
= compare_values (vr0
->max
, vr1
->max
);
6175 if (cmp
== 0 || cmp
== -1)
6182 /* Check for useless ranges. */
6183 if (INTEGRAL_TYPE_P (TREE_TYPE (min
))
6184 && ((vrp_val_is_min (min
) || is_overflow_infinity (min
))
6185 && (vrp_val_is_max (max
) || is_overflow_infinity (max
))))
6188 /* The resulting set of equivalences is the intersection of
6190 if (vr0
->equiv
&& vr1
->equiv
&& vr0
->equiv
!= vr1
->equiv
)
6191 bitmap_and_into (vr0
->equiv
, vr1
->equiv
);
6192 else if (vr0
->equiv
&& !vr1
->equiv
)
6193 bitmap_clear (vr0
->equiv
);
6195 set_value_range (vr0
, vr0
->type
, min
, max
, vr0
->equiv
);
6197 else if (vr0
->type
== VR_ANTI_RANGE
&& vr1
->type
== VR_ANTI_RANGE
)
6199 /* Two anti-ranges meet only if their complements intersect.
6200 Only handle the case of identical ranges. */
6201 if (compare_values (vr0
->min
, vr1
->min
) == 0
6202 && compare_values (vr0
->max
, vr1
->max
) == 0
6203 && compare_values (vr0
->min
, vr0
->max
) == 0)
6205 /* The resulting set of equivalences is the intersection of
6207 if (vr0
->equiv
&& vr1
->equiv
&& vr0
->equiv
!= vr1
->equiv
)
6208 bitmap_and_into (vr0
->equiv
, vr1
->equiv
);
6209 else if (vr0
->equiv
&& !vr1
->equiv
)
6210 bitmap_clear (vr0
->equiv
);
6215 else if (vr0
->type
== VR_ANTI_RANGE
|| vr1
->type
== VR_ANTI_RANGE
)
6217 /* For a numeric range [VAL1, VAL2] and an anti-range ~[VAL3, VAL4],
6218 only handle the case where the ranges have an empty intersection.
6219 The result of the meet operation is the anti-range. */
6220 if (!symbolic_range_p (vr0
)
6221 && !symbolic_range_p (vr1
)
6222 && !value_ranges_intersect_p (vr0
, vr1
))
6224 /* Copy most of VR1 into VR0. Don't copy VR1's equivalence
6225 set. We need to compute the intersection of the two
6226 equivalence sets. */
6227 if (vr1
->type
== VR_ANTI_RANGE
)
6228 set_value_range (vr0
, vr1
->type
, vr1
->min
, vr1
->max
, vr0
->equiv
);
6230 /* The resulting set of equivalences is the intersection of
6232 if (vr0
->equiv
&& vr1
->equiv
&& vr0
->equiv
!= vr1
->equiv
)
6233 bitmap_and_into (vr0
->equiv
, vr1
->equiv
);
6234 else if (vr0
->equiv
&& !vr1
->equiv
)
6235 bitmap_clear (vr0
->equiv
);
6246 /* Failed to find an efficient meet. Before giving up and setting
6247 the result to VARYING, see if we can at least derive a useful
6248 anti-range. FIXME, all this nonsense about distinguishing
6249 anti-ranges from ranges is necessary because of the odd
6250 semantics of range_includes_zero_p and friends. */
6251 if (!symbolic_range_p (vr0
)
6252 && ((vr0
->type
== VR_RANGE
&& !range_includes_zero_p (vr0
))
6253 || (vr0
->type
== VR_ANTI_RANGE
&& range_includes_zero_p (vr0
)))
6254 && !symbolic_range_p (vr1
)
6255 && ((vr1
->type
== VR_RANGE
&& !range_includes_zero_p (vr1
))
6256 || (vr1
->type
== VR_ANTI_RANGE
&& range_includes_zero_p (vr1
))))
6258 set_value_range_to_nonnull (vr0
, TREE_TYPE (vr0
->min
));
6260 /* Since this meet operation did not result from the meeting of
6261 two equivalent names, VR0 cannot have any equivalences. */
6263 bitmap_clear (vr0
->equiv
);
6266 set_value_range_to_varying (vr0
);
6270 /* Visit all arguments for PHI node PHI that flow through executable
6271 edges. If a valid value range can be derived from all the incoming
6272 value ranges, set a new range for the LHS of PHI. */
6274 static enum ssa_prop_result
6275 vrp_visit_phi_node (gimple phi
)
6278 tree lhs
= PHI_RESULT (phi
);
6279 value_range_t
*lhs_vr
= get_value_range (lhs
);
6280 value_range_t vr_result
= { VR_UNDEFINED
, NULL_TREE
, NULL_TREE
, NULL
};
6281 int edges
, old_edges
;
6283 copy_value_range (&vr_result
, lhs_vr
);
6285 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
6287 fprintf (dump_file
, "\nVisiting PHI node: ");
6288 print_gimple_stmt (dump_file
, phi
, 0, dump_flags
);
6292 for (i
= 0; i
< gimple_phi_num_args (phi
); i
++)
6294 edge e
= gimple_phi_arg_edge (phi
, i
);
6296 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
6299 "\n Argument #%d (%d -> %d %sexecutable)\n",
6300 (int) i
, e
->src
->index
, e
->dest
->index
,
6301 (e
->flags
& EDGE_EXECUTABLE
) ? "" : "not ");
6304 if (e
->flags
& EDGE_EXECUTABLE
)
6306 tree arg
= PHI_ARG_DEF (phi
, i
);
6307 value_range_t vr_arg
;
6311 if (TREE_CODE (arg
) == SSA_NAME
)
6313 vr_arg
= *(get_value_range (arg
));
6317 if (is_overflow_infinity (arg
))
6319 arg
= copy_node (arg
);
6320 TREE_OVERFLOW (arg
) = 0;
6323 vr_arg
.type
= VR_RANGE
;
6326 vr_arg
.equiv
= NULL
;
6329 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
6331 fprintf (dump_file
, "\t");
6332 print_generic_expr (dump_file
, arg
, dump_flags
);
6333 fprintf (dump_file
, "\n\tValue: ");
6334 dump_value_range (dump_file
, &vr_arg
);
6335 fprintf (dump_file
, "\n");
6338 vrp_meet (&vr_result
, &vr_arg
);
6340 if (vr_result
.type
== VR_VARYING
)
6345 if (vr_result
.type
== VR_VARYING
)
6348 old_edges
= vr_phi_edge_counts
[SSA_NAME_VERSION (lhs
)];
6349 vr_phi_edge_counts
[SSA_NAME_VERSION (lhs
)] = edges
;
6351 /* To prevent infinite iterations in the algorithm, derive ranges
6352 when the new value is slightly bigger or smaller than the
6353 previous one. We don't do this if we have seen a new executable
6354 edge; this helps us avoid an overflow infinity for conditionals
6355 which are not in a loop. */
6356 if (lhs_vr
->type
== VR_RANGE
&& vr_result
.type
== VR_RANGE
6357 && edges
<= old_edges
)
6359 if (!POINTER_TYPE_P (TREE_TYPE (lhs
)))
6361 int cmp_min
= compare_values (lhs_vr
->min
, vr_result
.min
);
6362 int cmp_max
= compare_values (lhs_vr
->max
, vr_result
.max
);
6364 /* If the new minimum is smaller or larger than the previous
6365 one, go all the way to -INF. In the first case, to avoid
6366 iterating millions of times to reach -INF, and in the
6367 other case to avoid infinite bouncing between different
6369 if (cmp_min
> 0 || cmp_min
< 0)
6371 /* If we will end up with a (-INF, +INF) range, set it to
6372 VARYING. Same if the previous max value was invalid for
6373 the type and we'd end up with vr_result.min > vr_result.max. */
6374 if (vrp_val_is_max (vr_result
.max
)
6375 || compare_values (TYPE_MIN_VALUE (TREE_TYPE (vr_result
.min
)),
6379 if (!needs_overflow_infinity (TREE_TYPE (vr_result
.min
))
6380 || !vrp_var_may_overflow (lhs
, phi
))
6381 vr_result
.min
= TYPE_MIN_VALUE (TREE_TYPE (vr_result
.min
));
6382 else if (supports_overflow_infinity (TREE_TYPE (vr_result
.min
)))
6384 negative_overflow_infinity (TREE_TYPE (vr_result
.min
));
6389 /* Similarly, if the new maximum is smaller or larger than
6390 the previous one, go all the way to +INF. */
6391 if (cmp_max
< 0 || cmp_max
> 0)
6393 /* If we will end up with a (-INF, +INF) range, set it to
6394 VARYING. Same if the previous min value was invalid for
6395 the type and we'd end up with vr_result.max < vr_result.min. */
6396 if (vrp_val_is_min (vr_result
.min
)
6397 || compare_values (TYPE_MAX_VALUE (TREE_TYPE (vr_result
.max
)),
6401 if (!needs_overflow_infinity (TREE_TYPE (vr_result
.max
))
6402 || !vrp_var_may_overflow (lhs
, phi
))
6403 vr_result
.max
= TYPE_MAX_VALUE (TREE_TYPE (vr_result
.max
));
6404 else if (supports_overflow_infinity (TREE_TYPE (vr_result
.max
)))
6406 positive_overflow_infinity (TREE_TYPE (vr_result
.max
));
6413 /* If the new range is different than the previous value, keep
6415 if (update_value_range (lhs
, &vr_result
))
6416 return SSA_PROP_INTERESTING
;
6418 /* Nothing changed, don't add outgoing edges. */
6419 return SSA_PROP_NOT_INTERESTING
;
6421 /* No match found. Set the LHS to VARYING. */
6423 set_value_range_to_varying (lhs_vr
);
6424 return SSA_PROP_VARYING
;
6427 /* Simplify boolean operations if the source is known
6428 to be already a boolean. */
6430 simplify_truth_ops_using_ranges (gimple_stmt_iterator
*gsi
, gimple stmt
)
6432 enum tree_code rhs_code
= gimple_assign_rhs_code (stmt
);
6437 bool need_conversion
;
6439 op0
= gimple_assign_rhs1 (stmt
);
6440 if (TYPE_PRECISION (TREE_TYPE (op0
)) != 1)
6442 if (TREE_CODE (op0
) != SSA_NAME
)
6444 vr
= get_value_range (op0
);
6446 val
= compare_range_with_value (GE_EXPR
, vr
, integer_zero_node
, &sop
);
6447 if (!val
|| !integer_onep (val
))
6450 val
= compare_range_with_value (LE_EXPR
, vr
, integer_one_node
, &sop
);
6451 if (!val
|| !integer_onep (val
))
6455 if (rhs_code
== TRUTH_NOT_EXPR
)
6458 op1
= build_int_cst (TREE_TYPE (op0
), 1);
6462 op1
= gimple_assign_rhs2 (stmt
);
6464 /* Reduce number of cases to handle. */
6465 if (is_gimple_min_invariant (op1
))
6467 /* Exclude anything that should have been already folded. */
6468 if (rhs_code
!= EQ_EXPR
6469 && rhs_code
!= NE_EXPR
6470 && rhs_code
!= TRUTH_XOR_EXPR
)
6473 if (!integer_zerop (op1
)
6474 && !integer_onep (op1
)
6475 && !integer_all_onesp (op1
))
6478 /* Limit the number of cases we have to consider. */
6479 if (rhs_code
== EQ_EXPR
)
6482 op1
= fold_unary (TRUTH_NOT_EXPR
, TREE_TYPE (op1
), op1
);
6487 /* Punt on A == B as there is no BIT_XNOR_EXPR. */
6488 if (rhs_code
== EQ_EXPR
)
6491 if (TYPE_PRECISION (TREE_TYPE (op1
)) != 1)
6493 vr
= get_value_range (op1
);
6494 val
= compare_range_with_value (GE_EXPR
, vr
, integer_zero_node
, &sop
);
6495 if (!val
|| !integer_onep (val
))
6498 val
= compare_range_with_value (LE_EXPR
, vr
, integer_one_node
, &sop
);
6499 if (!val
|| !integer_onep (val
))
6505 if (sop
&& issue_strict_overflow_warning (WARN_STRICT_OVERFLOW_MISC
))
6507 location_t location
;
6509 if (!gimple_has_location (stmt
))
6510 location
= input_location
;
6512 location
= gimple_location (stmt
);
6514 if (rhs_code
== TRUTH_AND_EXPR
|| rhs_code
== TRUTH_OR_EXPR
)
6515 warning_at (location
, OPT_Wstrict_overflow
,
6516 _("assuming signed overflow does not occur when "
6517 "simplifying && or || to & or |"));
6519 warning_at (location
, OPT_Wstrict_overflow
,
6520 _("assuming signed overflow does not occur when "
6521 "simplifying ==, != or ! to identity or ^"));
6525 !useless_type_conversion_p (TREE_TYPE (gimple_assign_lhs (stmt
)),
6528 /* Make sure to not sign-extend -1 as a boolean value. */
6530 && !TYPE_UNSIGNED (TREE_TYPE (op0
))
6531 && TYPE_PRECISION (TREE_TYPE (op0
)) == 1)
6536 case TRUTH_AND_EXPR
:
6537 rhs_code
= BIT_AND_EXPR
;
6540 rhs_code
= BIT_IOR_EXPR
;
6542 case TRUTH_XOR_EXPR
:
6544 if (integer_zerop (op1
))
6546 gimple_assign_set_rhs_with_ops (gsi
,
6547 need_conversion
? NOP_EXPR
: SSA_NAME
,
6549 update_stmt (gsi_stmt (*gsi
));
6553 rhs_code
= BIT_XOR_EXPR
;
6559 if (need_conversion
)
6562 gimple_assign_set_rhs_with_ops (gsi
, rhs_code
, op0
, op1
);
6563 update_stmt (gsi_stmt (*gsi
));
6567 /* Simplify a division or modulo operator to a right shift or
6568 bitwise and if the first operand is unsigned or is greater
6569 than zero and the second operand is an exact power of two. */
6572 simplify_div_or_mod_using_ranges (gimple stmt
)
6574 enum tree_code rhs_code
= gimple_assign_rhs_code (stmt
);
6576 tree op0
= gimple_assign_rhs1 (stmt
);
6577 tree op1
= gimple_assign_rhs2 (stmt
);
6578 value_range_t
*vr
= get_value_range (gimple_assign_rhs1 (stmt
));
6580 if (TYPE_UNSIGNED (TREE_TYPE (op0
)))
6582 val
= integer_one_node
;
6588 val
= compare_range_with_value (GE_EXPR
, vr
, integer_zero_node
, &sop
);
6592 && integer_onep (val
)
6593 && issue_strict_overflow_warning (WARN_STRICT_OVERFLOW_MISC
))
6595 location_t location
;
6597 if (!gimple_has_location (stmt
))
6598 location
= input_location
;
6600 location
= gimple_location (stmt
);
6601 warning_at (location
, OPT_Wstrict_overflow
,
6602 "assuming signed overflow does not occur when "
6603 "simplifying %</%> or %<%%%> to %<>>%> or %<&%>");
6607 if (val
&& integer_onep (val
))
6611 if (rhs_code
== TRUNC_DIV_EXPR
)
6613 t
= build_int_cst (NULL_TREE
, tree_log2 (op1
));
6614 gimple_assign_set_rhs_code (stmt
, RSHIFT_EXPR
);
6615 gimple_assign_set_rhs1 (stmt
, op0
);
6616 gimple_assign_set_rhs2 (stmt
, t
);
6620 t
= build_int_cst (TREE_TYPE (op1
), 1);
6621 t
= int_const_binop (MINUS_EXPR
, op1
, t
, 0);
6622 t
= fold_convert (TREE_TYPE (op0
), t
);
6624 gimple_assign_set_rhs_code (stmt
, BIT_AND_EXPR
);
6625 gimple_assign_set_rhs1 (stmt
, op0
);
6626 gimple_assign_set_rhs2 (stmt
, t
);
6636 /* If the operand to an ABS_EXPR is >= 0, then eliminate the
6637 ABS_EXPR. If the operand is <= 0, then simplify the
6638 ABS_EXPR into a NEGATE_EXPR. */
6641 simplify_abs_using_ranges (gimple stmt
)
6644 tree op
= gimple_assign_rhs1 (stmt
);
6645 tree type
= TREE_TYPE (op
);
6646 value_range_t
*vr
= get_value_range (op
);
6648 if (TYPE_UNSIGNED (type
))
6650 val
= integer_zero_node
;
6656 val
= compare_range_with_value (LE_EXPR
, vr
, integer_zero_node
, &sop
);
6660 val
= compare_range_with_value (GE_EXPR
, vr
, integer_zero_node
,
6665 if (integer_zerop (val
))
6666 val
= integer_one_node
;
6667 else if (integer_onep (val
))
6668 val
= integer_zero_node
;
6673 && (integer_onep (val
) || integer_zerop (val
)))
6675 if (sop
&& issue_strict_overflow_warning (WARN_STRICT_OVERFLOW_MISC
))
6677 location_t location
;
6679 if (!gimple_has_location (stmt
))
6680 location
= input_location
;
6682 location
= gimple_location (stmt
);
6683 warning_at (location
, OPT_Wstrict_overflow
,
6684 "assuming signed overflow does not occur when "
6685 "simplifying %<abs (X)%> to %<X%> or %<-X%>");
6688 gimple_assign_set_rhs1 (stmt
, op
);
6689 if (integer_onep (val
))
6690 gimple_assign_set_rhs_code (stmt
, NEGATE_EXPR
);
6692 gimple_assign_set_rhs_code (stmt
, SSA_NAME
);
6701 /* We are comparing trees OP0 and OP1 using COND_CODE. OP0 has
6702 a known value range VR.
6704 If there is one and only one value which will satisfy the
6705 conditional, then return that value. Else return NULL. */
6708 test_for_singularity (enum tree_code cond_code
, tree op0
,
6709 tree op1
, value_range_t
*vr
)
6714 /* Extract minimum/maximum values which satisfy the
6715 the conditional as it was written. */
6716 if (cond_code
== LE_EXPR
|| cond_code
== LT_EXPR
)
6718 /* This should not be negative infinity; there is no overflow
6720 min
= TYPE_MIN_VALUE (TREE_TYPE (op0
));
6723 if (cond_code
== LT_EXPR
&& !is_overflow_infinity (max
))
6725 tree one
= build_int_cst (TREE_TYPE (op0
), 1);
6726 max
= fold_build2 (MINUS_EXPR
, TREE_TYPE (op0
), max
, one
);
6728 TREE_NO_WARNING (max
) = 1;
6731 else if (cond_code
== GE_EXPR
|| cond_code
== GT_EXPR
)
6733 /* This should not be positive infinity; there is no overflow
6735 max
= TYPE_MAX_VALUE (TREE_TYPE (op0
));
6738 if (cond_code
== GT_EXPR
&& !is_overflow_infinity (min
))
6740 tree one
= build_int_cst (TREE_TYPE (op0
), 1);
6741 min
= fold_build2 (PLUS_EXPR
, TREE_TYPE (op0
), min
, one
);
6743 TREE_NO_WARNING (min
) = 1;
6747 /* Now refine the minimum and maximum values using any
6748 value range information we have for op0. */
6751 if (compare_values (vr
->min
, min
) == -1)
6755 if (compare_values (vr
->max
, max
) == 1)
6760 /* If the new min/max values have converged to a single value,
6761 then there is only one value which can satisfy the condition,
6762 return that value. */
6763 if (operand_equal_p (min
, max
, 0) && is_gimple_min_invariant (min
))
6769 /* Simplify a conditional using a relational operator to an equality
6770 test if the range information indicates only one value can satisfy
6771 the original conditional. */
6774 simplify_cond_using_ranges (gimple stmt
)
6776 tree op0
= gimple_cond_lhs (stmt
);
6777 tree op1
= gimple_cond_rhs (stmt
);
6778 enum tree_code cond_code
= gimple_cond_code (stmt
);
6780 if (cond_code
!= NE_EXPR
6781 && cond_code
!= EQ_EXPR
6782 && TREE_CODE (op0
) == SSA_NAME
6783 && INTEGRAL_TYPE_P (TREE_TYPE (op0
))
6784 && is_gimple_min_invariant (op1
))
6786 value_range_t
*vr
= get_value_range (op0
);
6788 /* If we have range information for OP0, then we might be
6789 able to simplify this conditional. */
6790 if (vr
->type
== VR_RANGE
)
6792 tree new_tree
= test_for_singularity (cond_code
, op0
, op1
, vr
);
6798 fprintf (dump_file
, "Simplified relational ");
6799 print_gimple_stmt (dump_file
, stmt
, 0, 0);
6800 fprintf (dump_file
, " into ");
6803 gimple_cond_set_code (stmt
, EQ_EXPR
);
6804 gimple_cond_set_lhs (stmt
, op0
);
6805 gimple_cond_set_rhs (stmt
, new_tree
);
6811 print_gimple_stmt (dump_file
, stmt
, 0, 0);
6812 fprintf (dump_file
, "\n");
6818 /* Try again after inverting the condition. We only deal
6819 with integral types here, so no need to worry about
6820 issues with inverting FP comparisons. */
6821 cond_code
= invert_tree_comparison (cond_code
, false);
6822 new_tree
= test_for_singularity (cond_code
, op0
, op1
, vr
);
6828 fprintf (dump_file
, "Simplified relational ");
6829 print_gimple_stmt (dump_file
, stmt
, 0, 0);
6830 fprintf (dump_file
, " into ");
6833 gimple_cond_set_code (stmt
, NE_EXPR
);
6834 gimple_cond_set_lhs (stmt
, op0
);
6835 gimple_cond_set_rhs (stmt
, new_tree
);
6841 print_gimple_stmt (dump_file
, stmt
, 0, 0);
6842 fprintf (dump_file
, "\n");
6853 /* Simplify a switch statement using the value range of the switch
6857 simplify_switch_using_ranges (gimple stmt
)
6859 tree op
= gimple_switch_index (stmt
);
6864 size_t i
= 0, j
= 0, n
, n2
;
6868 if (TREE_CODE (op
) == SSA_NAME
)
6870 vr
= get_value_range (op
);
6872 /* We can only handle integer ranges. */
6873 if (vr
->type
!= VR_RANGE
6874 || symbolic_range_p (vr
))
6877 /* Find case label for min/max of the value range. */
6878 take_default
= !find_case_label_range (stmt
, vr
->min
, vr
->max
, &i
, &j
);
6880 else if (TREE_CODE (op
) == INTEGER_CST
)
6882 take_default
= !find_case_label_index (stmt
, 1, op
, &i
);
6896 n
= gimple_switch_num_labels (stmt
);
6898 /* Bail out if this is just all edges taken. */
6904 /* Build a new vector of taken case labels. */
6905 vec2
= make_tree_vec (j
- i
+ 1 + (int)take_default
);
6908 /* Add the default edge, if necessary. */
6910 TREE_VEC_ELT (vec2
, n2
++) = gimple_switch_default_label (stmt
);
6912 for (; i
<= j
; ++i
, ++n2
)
6913 TREE_VEC_ELT (vec2
, n2
) = gimple_switch_label (stmt
, i
);
6915 /* Mark needed edges. */
6916 for (i
= 0; i
< n2
; ++i
)
6918 e
= find_edge (gimple_bb (stmt
),
6919 label_to_block (CASE_LABEL (TREE_VEC_ELT (vec2
, i
))));
6920 e
->aux
= (void *)-1;
6923 /* Queue not needed edges for later removal. */
6924 FOR_EACH_EDGE (e
, ei
, gimple_bb (stmt
)->succs
)
6926 if (e
->aux
== (void *)-1)
6932 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
6934 fprintf (dump_file
, "removing unreachable case label\n");
6936 VEC_safe_push (edge
, heap
, to_remove_edges
, e
);
6939 /* And queue an update for the stmt. */
6942 VEC_safe_push (switch_update
, heap
, to_update_switch_stmts
, &su
);
6946 /* Simplify STMT using ranges if possible. */
6949 simplify_stmt_using_ranges (gimple_stmt_iterator
*gsi
)
6951 gimple stmt
= gsi_stmt (*gsi
);
6952 if (is_gimple_assign (stmt
))
6954 enum tree_code rhs_code
= gimple_assign_rhs_code (stmt
);
6960 case TRUTH_NOT_EXPR
:
6961 case TRUTH_AND_EXPR
:
6963 case TRUTH_XOR_EXPR
:
6964 /* Transform EQ_EXPR, NE_EXPR, TRUTH_NOT_EXPR into BIT_XOR_EXPR
6965 or identity if the RHS is zero or one, and the LHS are known
6966 to be boolean values. Transform all TRUTH_*_EXPR into
6967 BIT_*_EXPR if both arguments are known to be boolean values. */
6968 if (INTEGRAL_TYPE_P (TREE_TYPE (gimple_assign_rhs1 (stmt
))))
6969 return simplify_truth_ops_using_ranges (gsi
, stmt
);
6972 /* Transform TRUNC_DIV_EXPR and TRUNC_MOD_EXPR into RSHIFT_EXPR
6973 and BIT_AND_EXPR respectively if the first operand is greater
6974 than zero and the second operand is an exact power of two. */
6975 case TRUNC_DIV_EXPR
:
6976 case TRUNC_MOD_EXPR
:
6977 if (INTEGRAL_TYPE_P (TREE_TYPE (gimple_assign_rhs1 (stmt
)))
6978 && integer_pow2p (gimple_assign_rhs2 (stmt
)))
6979 return simplify_div_or_mod_using_ranges (stmt
);
6982 /* Transform ABS (X) into X or -X as appropriate. */
6984 if (TREE_CODE (gimple_assign_rhs1 (stmt
)) == SSA_NAME
6985 && INTEGRAL_TYPE_P (TREE_TYPE (gimple_assign_rhs1 (stmt
))))
6986 return simplify_abs_using_ranges (stmt
);
6993 else if (gimple_code (stmt
) == GIMPLE_COND
)
6994 return simplify_cond_using_ranges (stmt
);
6995 else if (gimple_code (stmt
) == GIMPLE_SWITCH
)
6996 return simplify_switch_using_ranges (stmt
);
7001 /* If the statement pointed by SI has a predicate whose value can be
7002 computed using the value range information computed by VRP, compute
7003 its value and return true. Otherwise, return false. */
7006 fold_predicate_in (gimple_stmt_iterator
*si
)
7008 bool assignment_p
= false;
7010 gimple stmt
= gsi_stmt (*si
);
7012 if (is_gimple_assign (stmt
)
7013 && TREE_CODE_CLASS (gimple_assign_rhs_code (stmt
)) == tcc_comparison
)
7015 assignment_p
= true;
7016 val
= vrp_evaluate_conditional (gimple_assign_rhs_code (stmt
),
7017 gimple_assign_rhs1 (stmt
),
7018 gimple_assign_rhs2 (stmt
),
7021 else if (gimple_code (stmt
) == GIMPLE_COND
)
7022 val
= vrp_evaluate_conditional (gimple_cond_code (stmt
),
7023 gimple_cond_lhs (stmt
),
7024 gimple_cond_rhs (stmt
),
7032 val
= fold_convert (gimple_expr_type (stmt
), val
);
7036 fprintf (dump_file
, "Folding predicate ");
7037 print_gimple_expr (dump_file
, stmt
, 0, 0);
7038 fprintf (dump_file
, " to ");
7039 print_generic_expr (dump_file
, val
, 0);
7040 fprintf (dump_file
, "\n");
7043 if (is_gimple_assign (stmt
))
7044 gimple_assign_set_rhs_from_tree (si
, val
);
7047 gcc_assert (gimple_code (stmt
) == GIMPLE_COND
);
7048 if (integer_zerop (val
))
7049 gimple_cond_make_false (stmt
);
7050 else if (integer_onep (val
))
7051 gimple_cond_make_true (stmt
);
7062 /* Callback for substitute_and_fold folding the stmt at *SI. */
7065 vrp_fold_stmt (gimple_stmt_iterator
*si
)
7067 if (fold_predicate_in (si
))
7070 return simplify_stmt_using_ranges (si
);
7073 /* Stack of dest,src equivalency pairs that need to be restored after
7074 each attempt to thread a block's incoming edge to an outgoing edge.
7076 A NULL entry is used to mark the end of pairs which need to be
7078 static VEC(tree
,heap
) *stack
;
7080 /* A trivial wrapper so that we can present the generic jump threading
7081 code with a simple API for simplifying statements. STMT is the
7082 statement we want to simplify, WITHIN_STMT provides the location
7083 for any overflow warnings. */
7086 simplify_stmt_for_jump_threading (gimple stmt
, gimple within_stmt
)
7088 /* We only use VRP information to simplify conditionals. This is
7089 overly conservative, but it's unclear if doing more would be
7090 worth the compile time cost. */
7091 if (gimple_code (stmt
) != GIMPLE_COND
)
7094 return vrp_evaluate_conditional (gimple_cond_code (stmt
),
7095 gimple_cond_lhs (stmt
),
7096 gimple_cond_rhs (stmt
), within_stmt
);
7099 /* Blocks which have more than one predecessor and more than
7100 one successor present jump threading opportunities, i.e.,
7101 when the block is reached from a specific predecessor, we
7102 may be able to determine which of the outgoing edges will
7103 be traversed. When this optimization applies, we are able
7104 to avoid conditionals at runtime and we may expose secondary
7105 optimization opportunities.
7107 This routine is effectively a driver for the generic jump
7108 threading code. It basically just presents the generic code
7109 with edges that may be suitable for jump threading.
7111 Unlike DOM, we do not iterate VRP if jump threading was successful.
7112 While iterating may expose new opportunities for VRP, it is expected
7113 those opportunities would be very limited and the compile time cost
7114 to expose those opportunities would be significant.
7116 As jump threading opportunities are discovered, they are registered
7117 for later realization. */
7120 identify_jump_threads (void)
7127 /* Ugh. When substituting values earlier in this pass we can
7128 wipe the dominance information. So rebuild the dominator
7129 information as we need it within the jump threading code. */
7130 calculate_dominance_info (CDI_DOMINATORS
);
7132 /* We do not allow VRP information to be used for jump threading
7133 across a back edge in the CFG. Otherwise it becomes too
7134 difficult to avoid eliminating loop exit tests. Of course
7135 EDGE_DFS_BACK is not accurate at this time so we have to
7137 mark_dfs_back_edges ();
7139 /* Do not thread across edges we are about to remove. Just marking
7140 them as EDGE_DFS_BACK will do. */
7141 for (i
= 0; VEC_iterate (edge
, to_remove_edges
, i
, e
); ++i
)
7142 e
->flags
|= EDGE_DFS_BACK
;
7144 /* Allocate our unwinder stack to unwind any temporary equivalences
7145 that might be recorded. */
7146 stack
= VEC_alloc (tree
, heap
, 20);
7148 /* To avoid lots of silly node creation, we create a single
7149 conditional and just modify it in-place when attempting to
7151 dummy
= gimple_build_cond (EQ_EXPR
,
7152 integer_zero_node
, integer_zero_node
,
7155 /* Walk through all the blocks finding those which present a
7156 potential jump threading opportunity. We could set this up
7157 as a dominator walker and record data during the walk, but
7158 I doubt it's worth the effort for the classes of jump
7159 threading opportunities we are trying to identify at this
7160 point in compilation. */
7165 /* If the generic jump threading code does not find this block
7166 interesting, then there is nothing to do. */
7167 if (! potentially_threadable_block (bb
))
7170 /* We only care about blocks ending in a COND_EXPR. While there
7171 may be some value in handling SWITCH_EXPR here, I doubt it's
7172 terribly important. */
7173 last
= gsi_stmt (gsi_last_bb (bb
));
7174 if (gimple_code (last
) != GIMPLE_COND
)
7177 /* We're basically looking for any kind of conditional with
7178 integral type arguments. */
7179 if (TREE_CODE (gimple_cond_lhs (last
)) == SSA_NAME
7180 && INTEGRAL_TYPE_P (TREE_TYPE (gimple_cond_lhs (last
)))
7181 && (TREE_CODE (gimple_cond_rhs (last
)) == SSA_NAME
7182 || is_gimple_min_invariant (gimple_cond_rhs (last
)))
7183 && INTEGRAL_TYPE_P (TREE_TYPE (gimple_cond_rhs (last
))))
7187 /* We've got a block with multiple predecessors and multiple
7188 successors which also ends in a suitable conditional. For
7189 each predecessor, see if we can thread it to a specific
7191 FOR_EACH_EDGE (e
, ei
, bb
->preds
)
7193 /* Do not thread across back edges or abnormal edges
7195 if (e
->flags
& (EDGE_DFS_BACK
| EDGE_COMPLEX
))
7198 thread_across_edge (dummy
, e
, true, &stack
,
7199 simplify_stmt_for_jump_threading
);
7204 /* We do not actually update the CFG or SSA graphs at this point as
7205 ASSERT_EXPRs are still in the IL and cfg cleanup code does not yet
7206 handle ASSERT_EXPRs gracefully. */
7209 /* We identified all the jump threading opportunities earlier, but could
7210 not transform the CFG at that time. This routine transforms the
7211 CFG and arranges for the dominator tree to be rebuilt if necessary.
7213 Note the SSA graph update will occur during the normal TODO
7214 processing by the pass manager. */
7216 finalize_jump_threads (void)
7218 thread_through_all_blocks (false);
7219 VEC_free (tree
, heap
, stack
);
7223 /* Traverse all the blocks folding conditionals with known ranges. */
7229 prop_value_t
*single_val_range
;
7230 bool do_value_subst_p
;
7234 fprintf (dump_file
, "\nValue ranges after VRP:\n\n");
7235 dump_all_value_ranges (dump_file
);
7236 fprintf (dump_file
, "\n");
7239 /* We may have ended with ranges that have exactly one value. Those
7240 values can be substituted as any other const propagated
7241 value using substitute_and_fold. */
7242 single_val_range
= XCNEWVEC (prop_value_t
, num_ssa_names
);
7244 do_value_subst_p
= false;
7245 for (i
= 0; i
< num_ssa_names
; i
++)
7247 && vr_value
[i
]->type
== VR_RANGE
7248 && vr_value
[i
]->min
== vr_value
[i
]->max
7249 && is_gimple_min_invariant (vr_value
[i
]->min
))
7251 single_val_range
[i
].value
= vr_value
[i
]->min
;
7252 do_value_subst_p
= true;
7255 if (!do_value_subst_p
)
7257 /* We found no single-valued ranges, don't waste time trying to
7258 do single value substitution in substitute_and_fold. */
7259 free (single_val_range
);
7260 single_val_range
= NULL
;
7263 substitute_and_fold (single_val_range
, vrp_fold_stmt
);
7265 if (warn_array_bounds
)
7266 check_all_array_refs ();
7268 /* We must identify jump threading opportunities before we release
7269 the datastructures built by VRP. */
7270 identify_jump_threads ();
7272 /* Free allocated memory. */
7273 for (i
= 0; i
< num_ssa_names
; i
++)
7276 BITMAP_FREE (vr_value
[i
]->equiv
);
7280 free (single_val_range
);
7282 free (vr_phi_edge_counts
);
7284 /* So that we can distinguish between VRP data being available
7285 and not available. */
7287 vr_phi_edge_counts
= NULL
;
7291 /* Main entry point to VRP (Value Range Propagation). This pass is
7292 loosely based on J. R. C. Patterson, ``Accurate Static Branch
7293 Prediction by Value Range Propagation,'' in SIGPLAN Conference on
7294 Programming Language Design and Implementation, pp. 67-78, 1995.
7295 Also available at http://citeseer.ist.psu.edu/patterson95accurate.html
7297 This is essentially an SSA-CCP pass modified to deal with ranges
7298 instead of constants.
7300 While propagating ranges, we may find that two or more SSA name
7301 have equivalent, though distinct ranges. For instance,
7304 2 p_4 = ASSERT_EXPR <p_3, p_3 != 0>
7306 4 p_5 = ASSERT_EXPR <p_4, p_4 == q_2>;
7310 In the code above, pointer p_5 has range [q_2, q_2], but from the
7311 code we can also determine that p_5 cannot be NULL and, if q_2 had
7312 a non-varying range, p_5's range should also be compatible with it.
7314 These equivalences are created by two expressions: ASSERT_EXPR and
7315 copy operations. Since p_5 is an assertion on p_4, and p_4 was the
7316 result of another assertion, then we can use the fact that p_5 and
7317 p_4 are equivalent when evaluating p_5's range.
7319 Together with value ranges, we also propagate these equivalences
7320 between names so that we can take advantage of information from
7321 multiple ranges when doing final replacement. Note that this
7322 equivalency relation is transitive but not symmetric.
7324 In the example above, p_5 is equivalent to p_4, q_2 and p_3, but we
7325 cannot assert that q_2 is equivalent to p_5 because q_2 may be used
7326 in contexts where that assertion does not hold (e.g., in line 6).
7328 TODO, the main difference between this pass and Patterson's is that
7329 we do not propagate edge probabilities. We only compute whether
7330 edges can be taken or not. That is, instead of having a spectrum
7331 of jump probabilities between 0 and 1, we only deal with 0, 1 and
7332 DON'T KNOW. In the future, it may be worthwhile to propagate
7333 probabilities to aid branch prediction. */
7342 loop_optimizer_init (LOOPS_NORMAL
| LOOPS_HAVE_RECORDED_EXITS
);
7343 rewrite_into_loop_closed_ssa (NULL
, TODO_update_ssa
);
7346 insert_range_assertions ();
7348 to_remove_edges
= VEC_alloc (edge
, heap
, 10);
7349 to_update_switch_stmts
= VEC_alloc (switch_update
, heap
, 5);
7350 threadedge_initialize_values ();
7353 ssa_propagate (vrp_visit_stmt
, vrp_visit_phi_node
);
7356 /* ASSERT_EXPRs must be removed before finalizing jump threads
7357 as finalizing jump threads calls the CFG cleanup code which
7358 does not properly handle ASSERT_EXPRs. */
7359 remove_range_assertions ();
7361 /* If we exposed any new variables, go ahead and put them into
7362 SSA form now, before we handle jump threading. This simplifies
7363 interactions between rewriting of _DECL nodes into SSA form
7364 and rewriting SSA_NAME nodes into SSA form after block
7365 duplication and CFG manipulation. */
7366 update_ssa (TODO_update_ssa
);
7368 finalize_jump_threads ();
7370 /* Remove dead edges from SWITCH_EXPR optimization. This leaves the
7371 CFG in a broken state and requires a cfg_cleanup run. */
7372 for (i
= 0; VEC_iterate (edge
, to_remove_edges
, i
, e
); ++i
)
7374 /* Update SWITCH_EXPR case label vector. */
7375 for (i
= 0; VEC_iterate (switch_update
, to_update_switch_stmts
, i
, su
); ++i
)
7378 size_t n
= TREE_VEC_LENGTH (su
->vec
);
7380 gimple_switch_set_num_labels (su
->stmt
, n
);
7381 for (j
= 0; j
< n
; j
++)
7382 gimple_switch_set_label (su
->stmt
, j
, TREE_VEC_ELT (su
->vec
, j
));
7383 /* As we may have replaced the default label with a regular one
7384 make sure to make it a real default label again. This ensures
7385 optimal expansion. */
7386 label
= gimple_switch_default_label (su
->stmt
);
7387 CASE_LOW (label
) = NULL_TREE
;
7388 CASE_HIGH (label
) = NULL_TREE
;
7391 if (VEC_length (edge
, to_remove_edges
) > 0)
7392 free_dominance_info (CDI_DOMINATORS
);
7394 VEC_free (edge
, heap
, to_remove_edges
);
7395 VEC_free (switch_update
, heap
, to_update_switch_stmts
);
7396 threadedge_finalize_values ();
7399 loop_optimizer_finalize ();
7406 return flag_tree_vrp
!= 0;
7409 struct gimple_opt_pass pass_vrp
=
7414 gate_vrp
, /* gate */
7415 execute_vrp
, /* execute */
7418 0, /* static_pass_number */
7419 TV_TREE_VRP
, /* tv_id */
7420 PROP_ssa
, /* properties_required */
7421 0, /* properties_provided */
7422 0, /* properties_destroyed */
7423 0, /* todo_flags_start */
7428 | TODO_update_ssa
/* todo_flags_finish */