1 /* Support routines for Value Range Propagation (VRP).
2 Copyright (C) 2005, 2006, 2007, 2008, 2009, 2010
3 Free Software Foundation, Inc.
4 Contributed by Diego Novillo <dnovillo@redhat.com>.
6 This file is part of GCC.
8 GCC is free software; you can redistribute it and/or modify
9 it under the terms of the GNU General Public License as published by
10 the Free Software Foundation; either version 3, or (at your option)
13 GCC is distributed in the hope that it will be useful,
14 but WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 GNU General Public License for more details.
18 You should have received a copy of the GNU General Public License
19 along with GCC; see the file COPYING3. If not see
20 <http://www.gnu.org/licenses/>. */
24 #include "coretypes.h"
29 #include "basic-block.h"
30 #include "tree-flow.h"
31 #include "tree-pass.h"
32 #include "tree-dump.h"
34 #include "tree-pretty-print.h"
35 #include "gimple-pretty-print.h"
39 #include "tree-scalar-evolution.h"
40 #include "tree-ssa-propagate.h"
41 #include "tree-chrec.h"
44 /* Set of SSA names found live during the RPO traversal of the function
45 for still active basic-blocks. */
48 /* Return true if the SSA name NAME is live on the edge E. */
51 live_on_edge (edge e
, tree name
)
53 return (live
[e
->dest
->index
]
54 && TEST_BIT (live
[e
->dest
->index
], SSA_NAME_VERSION (name
)));
57 /* Local functions. */
58 static int compare_values (tree val1
, tree val2
);
59 static int compare_values_warnv (tree val1
, tree val2
, bool *);
60 static void vrp_meet (value_range_t
*, value_range_t
*);
61 static tree
vrp_evaluate_conditional_warnv_with_ops (enum tree_code
,
62 tree
, tree
, bool, bool *,
65 /* Location information for ASSERT_EXPRs. Each instance of this
66 structure describes an ASSERT_EXPR for an SSA name. Since a single
67 SSA name may have more than one assertion associated with it, these
68 locations are kept in a linked list attached to the corresponding
72 /* Basic block where the assertion would be inserted. */
75 /* Some assertions need to be inserted on an edge (e.g., assertions
76 generated by COND_EXPRs). In those cases, BB will be NULL. */
79 /* Pointer to the statement that generated this assertion. */
80 gimple_stmt_iterator si
;
82 /* Predicate code for the ASSERT_EXPR. Must be COMPARISON_CLASS_P. */
83 enum tree_code comp_code
;
85 /* Value being compared against. */
88 /* Expression to compare. */
91 /* Next node in the linked list. */
92 struct assert_locus_d
*next
;
95 typedef struct assert_locus_d
*assert_locus_t
;
97 /* If bit I is present, it means that SSA name N_i has a list of
98 assertions that should be inserted in the IL. */
99 static bitmap need_assert_for
;
101 /* Array of locations lists where to insert assertions. ASSERTS_FOR[I]
102 holds a list of ASSERT_LOCUS_T nodes that describe where
103 ASSERT_EXPRs for SSA name N_I should be inserted. */
104 static assert_locus_t
*asserts_for
;
106 /* Value range array. After propagation, VR_VALUE[I] holds the range
107 of values that SSA name N_I may take. */
108 static value_range_t
**vr_value
;
110 /* For a PHI node which sets SSA name N_I, VR_COUNTS[I] holds the
111 number of executable edges we saw the last time we visited the
113 static int *vr_phi_edge_counts
;
120 static VEC (edge
, heap
) *to_remove_edges
;
121 DEF_VEC_O(switch_update
);
122 DEF_VEC_ALLOC_O(switch_update
, heap
);
123 static VEC (switch_update
, heap
) *to_update_switch_stmts
;
126 /* Return the maximum value for TYPE. */
129 vrp_val_max (const_tree type
)
131 if (!INTEGRAL_TYPE_P (type
))
134 return TYPE_MAX_VALUE (type
);
137 /* Return the minimum value for TYPE. */
140 vrp_val_min (const_tree type
)
142 if (!INTEGRAL_TYPE_P (type
))
145 return TYPE_MIN_VALUE (type
);
148 /* Return whether VAL is equal to the maximum value of its type. This
149 will be true for a positive overflow infinity. We can't do a
150 simple equality comparison with TYPE_MAX_VALUE because C typedefs
151 and Ada subtypes can produce types whose TYPE_MAX_VALUE is not ==
152 to the integer constant with the same value in the type. */
155 vrp_val_is_max (const_tree val
)
157 tree type_max
= vrp_val_max (TREE_TYPE (val
));
158 return (val
== type_max
159 || (type_max
!= NULL_TREE
160 && operand_equal_p (val
, type_max
, 0)));
163 /* Return whether VAL is equal to the minimum value of its type. This
164 will be true for a negative overflow infinity. */
167 vrp_val_is_min (const_tree val
)
169 tree type_min
= vrp_val_min (TREE_TYPE (val
));
170 return (val
== type_min
171 || (type_min
!= NULL_TREE
172 && operand_equal_p (val
, type_min
, 0)));
176 /* Return whether TYPE should use an overflow infinity distinct from
177 TYPE_{MIN,MAX}_VALUE. We use an overflow infinity value to
178 represent a signed overflow during VRP computations. An infinity
179 is distinct from a half-range, which will go from some number to
180 TYPE_{MIN,MAX}_VALUE. */
183 needs_overflow_infinity (const_tree type
)
185 return INTEGRAL_TYPE_P (type
) && !TYPE_OVERFLOW_WRAPS (type
);
188 /* Return whether TYPE can support our overflow infinity
189 representation: we use the TREE_OVERFLOW flag, which only exists
190 for constants. If TYPE doesn't support this, we don't optimize
191 cases which would require signed overflow--we drop them to
195 supports_overflow_infinity (const_tree type
)
197 tree min
= vrp_val_min (type
), max
= vrp_val_max (type
);
198 #ifdef ENABLE_CHECKING
199 gcc_assert (needs_overflow_infinity (type
));
201 return (min
!= NULL_TREE
202 && CONSTANT_CLASS_P (min
)
204 && CONSTANT_CLASS_P (max
));
207 /* VAL is the maximum or minimum value of a type. Return a
208 corresponding overflow infinity. */
211 make_overflow_infinity (tree val
)
213 #ifdef ENABLE_CHECKING
214 gcc_assert (val
!= NULL_TREE
&& CONSTANT_CLASS_P (val
));
216 val
= copy_node (val
);
217 TREE_OVERFLOW (val
) = 1;
221 /* Return a negative overflow infinity for TYPE. */
224 negative_overflow_infinity (tree type
)
226 #ifdef ENABLE_CHECKING
227 gcc_assert (supports_overflow_infinity (type
));
229 return make_overflow_infinity (vrp_val_min (type
));
232 /* Return a positive overflow infinity for TYPE. */
235 positive_overflow_infinity (tree type
)
237 #ifdef ENABLE_CHECKING
238 gcc_assert (supports_overflow_infinity (type
));
240 return make_overflow_infinity (vrp_val_max (type
));
243 /* Return whether VAL is a negative overflow infinity. */
246 is_negative_overflow_infinity (const_tree val
)
248 return (needs_overflow_infinity (TREE_TYPE (val
))
249 && CONSTANT_CLASS_P (val
)
250 && TREE_OVERFLOW (val
)
251 && vrp_val_is_min (val
));
254 /* Return whether VAL is a positive overflow infinity. */
257 is_positive_overflow_infinity (const_tree val
)
259 return (needs_overflow_infinity (TREE_TYPE (val
))
260 && CONSTANT_CLASS_P (val
)
261 && TREE_OVERFLOW (val
)
262 && vrp_val_is_max (val
));
265 /* Return whether VAL is a positive or negative overflow infinity. */
268 is_overflow_infinity (const_tree val
)
270 return (needs_overflow_infinity (TREE_TYPE (val
))
271 && CONSTANT_CLASS_P (val
)
272 && TREE_OVERFLOW (val
)
273 && (vrp_val_is_min (val
) || vrp_val_is_max (val
)));
276 /* Return whether STMT has a constant rhs that is_overflow_infinity. */
279 stmt_overflow_infinity (gimple stmt
)
281 if (is_gimple_assign (stmt
)
282 && get_gimple_rhs_class (gimple_assign_rhs_code (stmt
)) ==
284 return is_overflow_infinity (gimple_assign_rhs1 (stmt
));
288 /* If VAL is now an overflow infinity, return VAL. Otherwise, return
289 the same value with TREE_OVERFLOW clear. This can be used to avoid
290 confusing a regular value with an overflow value. */
293 avoid_overflow_infinity (tree val
)
295 if (!is_overflow_infinity (val
))
298 if (vrp_val_is_max (val
))
299 return vrp_val_max (TREE_TYPE (val
));
302 #ifdef ENABLE_CHECKING
303 gcc_assert (vrp_val_is_min (val
));
305 return vrp_val_min (TREE_TYPE (val
));
310 /* Return true if ARG is marked with the nonnull attribute in the
311 current function signature. */
314 nonnull_arg_p (const_tree arg
)
316 tree t
, attrs
, fntype
;
317 unsigned HOST_WIDE_INT arg_num
;
319 gcc_assert (TREE_CODE (arg
) == PARM_DECL
&& POINTER_TYPE_P (TREE_TYPE (arg
)));
321 /* The static chain decl is always non null. */
322 if (arg
== cfun
->static_chain_decl
)
325 fntype
= TREE_TYPE (current_function_decl
);
326 attrs
= lookup_attribute ("nonnull", TYPE_ATTRIBUTES (fntype
));
328 /* If "nonnull" wasn't specified, we know nothing about the argument. */
329 if (attrs
== NULL_TREE
)
332 /* If "nonnull" applies to all the arguments, then ARG is non-null. */
333 if (TREE_VALUE (attrs
) == NULL_TREE
)
336 /* Get the position number for ARG in the function signature. */
337 for (arg_num
= 1, t
= DECL_ARGUMENTS (current_function_decl
);
339 t
= TREE_CHAIN (t
), arg_num
++)
345 gcc_assert (t
== arg
);
347 /* Now see if ARG_NUM is mentioned in the nonnull list. */
348 for (t
= TREE_VALUE (attrs
); t
; t
= TREE_CHAIN (t
))
350 if (compare_tree_int (TREE_VALUE (t
), arg_num
) == 0)
358 /* Set value range VR to VR_VARYING. */
361 set_value_range_to_varying (value_range_t
*vr
)
363 vr
->type
= VR_VARYING
;
364 vr
->min
= vr
->max
= NULL_TREE
;
366 bitmap_clear (vr
->equiv
);
370 /* Set value range VR to {T, MIN, MAX, EQUIV}. */
373 set_value_range (value_range_t
*vr
, enum value_range_type t
, tree min
,
374 tree max
, bitmap equiv
)
376 #if defined ENABLE_CHECKING
377 /* Check the validity of the range. */
378 if (t
== VR_RANGE
|| t
== VR_ANTI_RANGE
)
382 gcc_assert (min
&& max
);
384 if (INTEGRAL_TYPE_P (TREE_TYPE (min
)) && t
== VR_ANTI_RANGE
)
385 gcc_assert (!vrp_val_is_min (min
) || !vrp_val_is_max (max
));
387 cmp
= compare_values (min
, max
);
388 gcc_assert (cmp
== 0 || cmp
== -1 || cmp
== -2);
390 if (needs_overflow_infinity (TREE_TYPE (min
)))
391 gcc_assert (!is_overflow_infinity (min
)
392 || !is_overflow_infinity (max
));
395 if (t
== VR_UNDEFINED
|| t
== VR_VARYING
)
396 gcc_assert (min
== NULL_TREE
&& max
== NULL_TREE
);
398 if (t
== VR_UNDEFINED
|| t
== VR_VARYING
)
399 gcc_assert (equiv
== NULL
|| bitmap_empty_p (equiv
));
406 /* Since updating the equivalence set involves deep copying the
407 bitmaps, only do it if absolutely necessary. */
408 if (vr
->equiv
== NULL
410 vr
->equiv
= BITMAP_ALLOC (NULL
);
412 if (equiv
!= vr
->equiv
)
414 if (equiv
&& !bitmap_empty_p (equiv
))
415 bitmap_copy (vr
->equiv
, equiv
);
417 bitmap_clear (vr
->equiv
);
422 /* Set value range VR to the canonical form of {T, MIN, MAX, EQUIV}.
423 This means adjusting T, MIN and MAX representing the case of a
424 wrapping range with MAX < MIN covering [MIN, type_max] U [type_min, MAX]
425 as anti-rage ~[MAX+1, MIN-1]. Likewise for wrapping anti-ranges.
426 In corner cases where MAX+1 or MIN-1 wraps this will fall back
428 This routine exists to ease canonicalization in the case where we
429 extract ranges from var + CST op limit. */
432 set_and_canonicalize_value_range (value_range_t
*vr
, enum value_range_type t
,
433 tree min
, tree max
, bitmap equiv
)
435 /* Nothing to canonicalize for symbolic or unknown or varying ranges. */
437 && t
!= VR_ANTI_RANGE
)
438 || TREE_CODE (min
) != INTEGER_CST
439 || TREE_CODE (max
) != INTEGER_CST
)
441 set_value_range (vr
, t
, min
, max
, equiv
);
445 /* Wrong order for min and max, to swap them and the VR type we need
447 if (tree_int_cst_lt (max
, min
))
449 tree one
= build_int_cst (TREE_TYPE (min
), 1);
450 tree tmp
= int_const_binop (PLUS_EXPR
, max
, one
, 0);
451 max
= int_const_binop (MINUS_EXPR
, min
, one
, 0);
454 /* There's one corner case, if we had [C+1, C] before we now have
455 that again. But this represents an empty value range, so drop
456 to varying in this case. */
457 if (tree_int_cst_lt (max
, min
))
459 set_value_range_to_varying (vr
);
463 t
= t
== VR_RANGE
? VR_ANTI_RANGE
: VR_RANGE
;
466 /* Anti-ranges that can be represented as ranges should be so. */
467 if (t
== VR_ANTI_RANGE
)
469 bool is_min
= vrp_val_is_min (min
);
470 bool is_max
= vrp_val_is_max (max
);
472 if (is_min
&& is_max
)
474 /* We cannot deal with empty ranges, drop to varying. */
475 set_value_range_to_varying (vr
);
479 /* As a special exception preserve non-null ranges. */
480 && !(TYPE_UNSIGNED (TREE_TYPE (min
))
481 && integer_zerop (max
)))
483 tree one
= build_int_cst (TREE_TYPE (max
), 1);
484 min
= int_const_binop (PLUS_EXPR
, max
, one
, 0);
485 max
= vrp_val_max (TREE_TYPE (max
));
490 tree one
= build_int_cst (TREE_TYPE (min
), 1);
491 max
= int_const_binop (MINUS_EXPR
, min
, one
, 0);
492 min
= vrp_val_min (TREE_TYPE (min
));
497 set_value_range (vr
, t
, min
, max
, equiv
);
500 /* Copy value range FROM into value range TO. */
503 copy_value_range (value_range_t
*to
, value_range_t
*from
)
505 set_value_range (to
, from
->type
, from
->min
, from
->max
, from
->equiv
);
508 /* Set value range VR to a single value. This function is only called
509 with values we get from statements, and exists to clear the
510 TREE_OVERFLOW flag so that we don't think we have an overflow
511 infinity when we shouldn't. */
514 set_value_range_to_value (value_range_t
*vr
, tree val
, bitmap equiv
)
516 gcc_assert (is_gimple_min_invariant (val
));
517 val
= avoid_overflow_infinity (val
);
518 set_value_range (vr
, VR_RANGE
, val
, val
, equiv
);
521 /* Set value range VR to a non-negative range of type TYPE.
522 OVERFLOW_INFINITY indicates whether to use an overflow infinity
523 rather than TYPE_MAX_VALUE; this should be true if we determine
524 that the range is nonnegative based on the assumption that signed
525 overflow does not occur. */
528 set_value_range_to_nonnegative (value_range_t
*vr
, tree type
,
529 bool overflow_infinity
)
533 if (overflow_infinity
&& !supports_overflow_infinity (type
))
535 set_value_range_to_varying (vr
);
539 zero
= build_int_cst (type
, 0);
540 set_value_range (vr
, VR_RANGE
, zero
,
542 ? positive_overflow_infinity (type
)
543 : TYPE_MAX_VALUE (type
)),
547 /* Set value range VR to a non-NULL range of type TYPE. */
550 set_value_range_to_nonnull (value_range_t
*vr
, tree type
)
552 tree zero
= build_int_cst (type
, 0);
553 set_value_range (vr
, VR_ANTI_RANGE
, zero
, zero
, vr
->equiv
);
557 /* Set value range VR to a NULL range of type TYPE. */
560 set_value_range_to_null (value_range_t
*vr
, tree type
)
562 set_value_range_to_value (vr
, build_int_cst (type
, 0), vr
->equiv
);
566 /* Set value range VR to a range of a truthvalue of type TYPE. */
569 set_value_range_to_truthvalue (value_range_t
*vr
, tree type
)
571 if (TYPE_PRECISION (type
) == 1)
572 set_value_range_to_varying (vr
);
574 set_value_range (vr
, VR_RANGE
,
575 build_int_cst (type
, 0), build_int_cst (type
, 1),
580 /* Set value range VR to VR_UNDEFINED. */
583 set_value_range_to_undefined (value_range_t
*vr
)
585 vr
->type
= VR_UNDEFINED
;
586 vr
->min
= vr
->max
= NULL_TREE
;
588 bitmap_clear (vr
->equiv
);
592 /* If abs (min) < abs (max), set VR to [-max, max], if
593 abs (min) >= abs (max), set VR to [-min, min]. */
596 abs_extent_range (value_range_t
*vr
, tree min
, tree max
)
600 gcc_assert (TREE_CODE (min
) == INTEGER_CST
);
601 gcc_assert (TREE_CODE (max
) == INTEGER_CST
);
602 gcc_assert (INTEGRAL_TYPE_P (TREE_TYPE (min
)));
603 gcc_assert (!TYPE_UNSIGNED (TREE_TYPE (min
)));
604 min
= fold_unary (ABS_EXPR
, TREE_TYPE (min
), min
);
605 max
= fold_unary (ABS_EXPR
, TREE_TYPE (max
), max
);
606 if (TREE_OVERFLOW (min
) || TREE_OVERFLOW (max
))
608 set_value_range_to_varying (vr
);
611 cmp
= compare_values (min
, max
);
613 min
= fold_unary (NEGATE_EXPR
, TREE_TYPE (min
), max
);
614 else if (cmp
== 0 || cmp
== 1)
617 min
= fold_unary (NEGATE_EXPR
, TREE_TYPE (min
), min
);
621 set_value_range_to_varying (vr
);
624 set_and_canonicalize_value_range (vr
, VR_RANGE
, min
, max
, NULL
);
628 /* Return value range information for VAR.
630 If we have no values ranges recorded (ie, VRP is not running), then
631 return NULL. Otherwise create an empty range if none existed for VAR. */
633 static value_range_t
*
634 get_value_range (const_tree var
)
638 unsigned ver
= SSA_NAME_VERSION (var
);
640 /* If we have no recorded ranges, then return NULL. */
648 /* Create a default value range. */
649 vr_value
[ver
] = vr
= XCNEW (value_range_t
);
651 /* Defer allocating the equivalence set. */
654 /* If VAR is a default definition, the variable can take any value
656 sym
= SSA_NAME_VAR (var
);
657 if (SSA_NAME_IS_DEFAULT_DEF (var
))
659 /* Try to use the "nonnull" attribute to create ~[0, 0]
660 anti-ranges for pointers. Note that this is only valid with
661 default definitions of PARM_DECLs. */
662 if (TREE_CODE (sym
) == PARM_DECL
663 && POINTER_TYPE_P (TREE_TYPE (sym
))
664 && nonnull_arg_p (sym
))
665 set_value_range_to_nonnull (vr
, TREE_TYPE (sym
));
667 set_value_range_to_varying (vr
);
673 /* Return true, if VAL1 and VAL2 are equal values for VRP purposes. */
676 vrp_operand_equal_p (const_tree val1
, const_tree val2
)
680 if (!val1
|| !val2
|| !operand_equal_p (val1
, val2
, 0))
682 if (is_overflow_infinity (val1
))
683 return is_overflow_infinity (val2
);
687 /* Return true, if the bitmaps B1 and B2 are equal. */
690 vrp_bitmap_equal_p (const_bitmap b1
, const_bitmap b2
)
694 && bitmap_equal_p (b1
, b2
)));
697 /* Update the value range and equivalence set for variable VAR to
698 NEW_VR. Return true if NEW_VR is different from VAR's previous
701 NOTE: This function assumes that NEW_VR is a temporary value range
702 object created for the sole purpose of updating VAR's range. The
703 storage used by the equivalence set from NEW_VR will be freed by
704 this function. Do not call update_value_range when NEW_VR
705 is the range object associated with another SSA name. */
708 update_value_range (const_tree var
, value_range_t
*new_vr
)
710 value_range_t
*old_vr
;
713 /* Update the value range, if necessary. */
714 old_vr
= get_value_range (var
);
715 is_new
= old_vr
->type
!= new_vr
->type
716 || !vrp_operand_equal_p (old_vr
->min
, new_vr
->min
)
717 || !vrp_operand_equal_p (old_vr
->max
, new_vr
->max
)
718 || !vrp_bitmap_equal_p (old_vr
->equiv
, new_vr
->equiv
);
721 set_value_range (old_vr
, new_vr
->type
, new_vr
->min
, new_vr
->max
,
724 BITMAP_FREE (new_vr
->equiv
);
730 /* Add VAR and VAR's equivalence set to EQUIV. This is the central
731 point where equivalence processing can be turned on/off. */
734 add_equivalence (bitmap
*equiv
, const_tree var
)
736 unsigned ver
= SSA_NAME_VERSION (var
);
737 value_range_t
*vr
= vr_value
[ver
];
740 *equiv
= BITMAP_ALLOC (NULL
);
741 bitmap_set_bit (*equiv
, ver
);
743 bitmap_ior_into (*equiv
, vr
->equiv
);
747 /* Return true if VR is ~[0, 0]. */
750 range_is_nonnull (value_range_t
*vr
)
752 return vr
->type
== VR_ANTI_RANGE
753 && integer_zerop (vr
->min
)
754 && integer_zerop (vr
->max
);
758 /* Return true if VR is [0, 0]. */
761 range_is_null (value_range_t
*vr
)
763 return vr
->type
== VR_RANGE
764 && integer_zerop (vr
->min
)
765 && integer_zerop (vr
->max
);
768 /* Return true if max and min of VR are INTEGER_CST. It's not necessary
772 range_int_cst_p (value_range_t
*vr
)
774 return (vr
->type
== VR_RANGE
775 && TREE_CODE (vr
->max
) == INTEGER_CST
776 && TREE_CODE (vr
->min
) == INTEGER_CST
777 && !TREE_OVERFLOW (vr
->max
)
778 && !TREE_OVERFLOW (vr
->min
));
781 /* Return true if VR is a INTEGER_CST singleton. */
784 range_int_cst_singleton_p (value_range_t
*vr
)
786 return (range_int_cst_p (vr
)
787 && tree_int_cst_equal (vr
->min
, vr
->max
));
790 /* Return true if value range VR involves at least one symbol. */
793 symbolic_range_p (value_range_t
*vr
)
795 return (!is_gimple_min_invariant (vr
->min
)
796 || !is_gimple_min_invariant (vr
->max
));
799 /* Return true if value range VR uses an overflow infinity. */
802 overflow_infinity_range_p (value_range_t
*vr
)
804 return (vr
->type
== VR_RANGE
805 && (is_overflow_infinity (vr
->min
)
806 || is_overflow_infinity (vr
->max
)));
809 /* Return false if we can not make a valid comparison based on VR;
810 this will be the case if it uses an overflow infinity and overflow
811 is not undefined (i.e., -fno-strict-overflow is in effect).
812 Otherwise return true, and set *STRICT_OVERFLOW_P to true if VR
813 uses an overflow infinity. */
816 usable_range_p (value_range_t
*vr
, bool *strict_overflow_p
)
818 gcc_assert (vr
->type
== VR_RANGE
);
819 if (is_overflow_infinity (vr
->min
))
821 *strict_overflow_p
= true;
822 if (!TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (vr
->min
)))
825 if (is_overflow_infinity (vr
->max
))
827 *strict_overflow_p
= true;
828 if (!TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (vr
->max
)))
835 /* Like tree_expr_nonnegative_warnv_p, but this function uses value
836 ranges obtained so far. */
839 vrp_expr_computes_nonnegative (tree expr
, bool *strict_overflow_p
)
841 return (tree_expr_nonnegative_warnv_p (expr
, strict_overflow_p
)
842 || (TREE_CODE (expr
) == SSA_NAME
843 && ssa_name_nonnegative_p (expr
)));
846 /* Return true if the result of assignment STMT is know to be non-negative.
847 If the return value is based on the assumption that signed overflow is
848 undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't change
849 *STRICT_OVERFLOW_P.*/
852 gimple_assign_nonnegative_warnv_p (gimple stmt
, bool *strict_overflow_p
)
854 enum tree_code code
= gimple_assign_rhs_code (stmt
);
855 switch (get_gimple_rhs_class (code
))
857 case GIMPLE_UNARY_RHS
:
858 return tree_unary_nonnegative_warnv_p (gimple_assign_rhs_code (stmt
),
859 gimple_expr_type (stmt
),
860 gimple_assign_rhs1 (stmt
),
862 case GIMPLE_BINARY_RHS
:
863 return tree_binary_nonnegative_warnv_p (gimple_assign_rhs_code (stmt
),
864 gimple_expr_type (stmt
),
865 gimple_assign_rhs1 (stmt
),
866 gimple_assign_rhs2 (stmt
),
868 case GIMPLE_TERNARY_RHS
:
870 case GIMPLE_SINGLE_RHS
:
871 return tree_single_nonnegative_warnv_p (gimple_assign_rhs1 (stmt
),
873 case GIMPLE_INVALID_RHS
:
880 /* Return true if return value of call STMT is know to be non-negative.
881 If the return value is based on the assumption that signed overflow is
882 undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't change
883 *STRICT_OVERFLOW_P.*/
886 gimple_call_nonnegative_warnv_p (gimple stmt
, bool *strict_overflow_p
)
888 tree arg0
= gimple_call_num_args (stmt
) > 0 ?
889 gimple_call_arg (stmt
, 0) : NULL_TREE
;
890 tree arg1
= gimple_call_num_args (stmt
) > 1 ?
891 gimple_call_arg (stmt
, 1) : NULL_TREE
;
893 return tree_call_nonnegative_warnv_p (gimple_expr_type (stmt
),
894 gimple_call_fndecl (stmt
),
900 /* Return true if STMT is know to to compute a non-negative value.
901 If the return value is based on the assumption that signed overflow is
902 undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't change
903 *STRICT_OVERFLOW_P.*/
906 gimple_stmt_nonnegative_warnv_p (gimple stmt
, bool *strict_overflow_p
)
908 switch (gimple_code (stmt
))
911 return gimple_assign_nonnegative_warnv_p (stmt
, strict_overflow_p
);
913 return gimple_call_nonnegative_warnv_p (stmt
, strict_overflow_p
);
919 /* Return true if the result of assignment STMT is know to be non-zero.
920 If the return value is based on the assumption that signed overflow is
921 undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't change
922 *STRICT_OVERFLOW_P.*/
925 gimple_assign_nonzero_warnv_p (gimple stmt
, bool *strict_overflow_p
)
927 enum tree_code code
= gimple_assign_rhs_code (stmt
);
928 switch (get_gimple_rhs_class (code
))
930 case GIMPLE_UNARY_RHS
:
931 return tree_unary_nonzero_warnv_p (gimple_assign_rhs_code (stmt
),
932 gimple_expr_type (stmt
),
933 gimple_assign_rhs1 (stmt
),
935 case GIMPLE_BINARY_RHS
:
936 return tree_binary_nonzero_warnv_p (gimple_assign_rhs_code (stmt
),
937 gimple_expr_type (stmt
),
938 gimple_assign_rhs1 (stmt
),
939 gimple_assign_rhs2 (stmt
),
941 case GIMPLE_TERNARY_RHS
:
943 case GIMPLE_SINGLE_RHS
:
944 return tree_single_nonzero_warnv_p (gimple_assign_rhs1 (stmt
),
946 case GIMPLE_INVALID_RHS
:
953 /* Return true if STMT is know to to compute a non-zero value.
954 If the return value is based on the assumption that signed overflow is
955 undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't change
956 *STRICT_OVERFLOW_P.*/
959 gimple_stmt_nonzero_warnv_p (gimple stmt
, bool *strict_overflow_p
)
961 switch (gimple_code (stmt
))
964 return gimple_assign_nonzero_warnv_p (stmt
, strict_overflow_p
);
966 return gimple_alloca_call_p (stmt
);
972 /* Like tree_expr_nonzero_warnv_p, but this function uses value ranges
976 vrp_stmt_computes_nonzero (gimple stmt
, bool *strict_overflow_p
)
978 if (gimple_stmt_nonzero_warnv_p (stmt
, strict_overflow_p
))
981 /* If we have an expression of the form &X->a, then the expression
982 is nonnull if X is nonnull. */
983 if (is_gimple_assign (stmt
)
984 && gimple_assign_rhs_code (stmt
) == ADDR_EXPR
)
986 tree expr
= gimple_assign_rhs1 (stmt
);
987 tree base
= get_base_address (TREE_OPERAND (expr
, 0));
989 if (base
!= NULL_TREE
990 && TREE_CODE (base
) == MEM_REF
991 && TREE_CODE (TREE_OPERAND (base
, 0)) == SSA_NAME
)
993 value_range_t
*vr
= get_value_range (TREE_OPERAND (base
, 0));
994 if (range_is_nonnull (vr
))
1002 /* Returns true if EXPR is a valid value (as expected by compare_values) --
1003 a gimple invariant, or SSA_NAME +- CST. */
1006 valid_value_p (tree expr
)
1008 if (TREE_CODE (expr
) == SSA_NAME
)
1011 if (TREE_CODE (expr
) == PLUS_EXPR
1012 || TREE_CODE (expr
) == MINUS_EXPR
)
1013 return (TREE_CODE (TREE_OPERAND (expr
, 0)) == SSA_NAME
1014 && TREE_CODE (TREE_OPERAND (expr
, 1)) == INTEGER_CST
);
1016 return is_gimple_min_invariant (expr
);
1022 -2 if those are incomparable. */
1024 operand_less_p (tree val
, tree val2
)
1026 /* LT is folded faster than GE and others. Inline the common case. */
1027 if (TREE_CODE (val
) == INTEGER_CST
&& TREE_CODE (val2
) == INTEGER_CST
)
1029 if (TYPE_UNSIGNED (TREE_TYPE (val
)))
1030 return INT_CST_LT_UNSIGNED (val
, val2
);
1033 if (INT_CST_LT (val
, val2
))
1041 fold_defer_overflow_warnings ();
1043 tcmp
= fold_binary_to_constant (LT_EXPR
, boolean_type_node
, val
, val2
);
1045 fold_undefer_and_ignore_overflow_warnings ();
1048 || TREE_CODE (tcmp
) != INTEGER_CST
)
1051 if (!integer_zerop (tcmp
))
1055 /* val >= val2, not considering overflow infinity. */
1056 if (is_negative_overflow_infinity (val
))
1057 return is_negative_overflow_infinity (val2
) ? 0 : 1;
1058 else if (is_positive_overflow_infinity (val2
))
1059 return is_positive_overflow_infinity (val
) ? 0 : 1;
1064 /* Compare two values VAL1 and VAL2. Return
1066 -2 if VAL1 and VAL2 cannot be compared at compile-time,
1069 +1 if VAL1 > VAL2, and
1072 This is similar to tree_int_cst_compare but supports pointer values
1073 and values that cannot be compared at compile time.
1075 If STRICT_OVERFLOW_P is not NULL, then set *STRICT_OVERFLOW_P to
1076 true if the return value is only valid if we assume that signed
1077 overflow is undefined. */
1080 compare_values_warnv (tree val1
, tree val2
, bool *strict_overflow_p
)
1085 /* Below we rely on the fact that VAL1 and VAL2 are both pointers or
1087 gcc_assert (POINTER_TYPE_P (TREE_TYPE (val1
))
1088 == POINTER_TYPE_P (TREE_TYPE (val2
)));
1089 /* Convert the two values into the same type. This is needed because
1090 sizetype causes sign extension even for unsigned types. */
1091 val2
= fold_convert (TREE_TYPE (val1
), val2
);
1092 STRIP_USELESS_TYPE_CONVERSION (val2
);
1094 if ((TREE_CODE (val1
) == SSA_NAME
1095 || TREE_CODE (val1
) == PLUS_EXPR
1096 || TREE_CODE (val1
) == MINUS_EXPR
)
1097 && (TREE_CODE (val2
) == SSA_NAME
1098 || TREE_CODE (val2
) == PLUS_EXPR
1099 || TREE_CODE (val2
) == MINUS_EXPR
))
1101 tree n1
, c1
, n2
, c2
;
1102 enum tree_code code1
, code2
;
1104 /* If VAL1 and VAL2 are of the form 'NAME [+-] CST' or 'NAME',
1105 return -1 or +1 accordingly. If VAL1 and VAL2 don't use the
1106 same name, return -2. */
1107 if (TREE_CODE (val1
) == SSA_NAME
)
1115 code1
= TREE_CODE (val1
);
1116 n1
= TREE_OPERAND (val1
, 0);
1117 c1
= TREE_OPERAND (val1
, 1);
1118 if (tree_int_cst_sgn (c1
) == -1)
1120 if (is_negative_overflow_infinity (c1
))
1122 c1
= fold_unary_to_constant (NEGATE_EXPR
, TREE_TYPE (c1
), c1
);
1125 code1
= code1
== MINUS_EXPR
? PLUS_EXPR
: MINUS_EXPR
;
1129 if (TREE_CODE (val2
) == SSA_NAME
)
1137 code2
= TREE_CODE (val2
);
1138 n2
= TREE_OPERAND (val2
, 0);
1139 c2
= TREE_OPERAND (val2
, 1);
1140 if (tree_int_cst_sgn (c2
) == -1)
1142 if (is_negative_overflow_infinity (c2
))
1144 c2
= fold_unary_to_constant (NEGATE_EXPR
, TREE_TYPE (c2
), c2
);
1147 code2
= code2
== MINUS_EXPR
? PLUS_EXPR
: MINUS_EXPR
;
1151 /* Both values must use the same name. */
1155 if (code1
== SSA_NAME
1156 && code2
== SSA_NAME
)
1160 /* If overflow is defined we cannot simplify more. */
1161 if (!TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (val1
)))
1164 if (strict_overflow_p
!= NULL
1165 && (code1
== SSA_NAME
|| !TREE_NO_WARNING (val1
))
1166 && (code2
== SSA_NAME
|| !TREE_NO_WARNING (val2
)))
1167 *strict_overflow_p
= true;
1169 if (code1
== SSA_NAME
)
1171 if (code2
== PLUS_EXPR
)
1172 /* NAME < NAME + CST */
1174 else if (code2
== MINUS_EXPR
)
1175 /* NAME > NAME - CST */
1178 else if (code1
== PLUS_EXPR
)
1180 if (code2
== SSA_NAME
)
1181 /* NAME + CST > NAME */
1183 else if (code2
== PLUS_EXPR
)
1184 /* NAME + CST1 > NAME + CST2, if CST1 > CST2 */
1185 return compare_values_warnv (c1
, c2
, strict_overflow_p
);
1186 else if (code2
== MINUS_EXPR
)
1187 /* NAME + CST1 > NAME - CST2 */
1190 else if (code1
== MINUS_EXPR
)
1192 if (code2
== SSA_NAME
)
1193 /* NAME - CST < NAME */
1195 else if (code2
== PLUS_EXPR
)
1196 /* NAME - CST1 < NAME + CST2 */
1198 else if (code2
== MINUS_EXPR
)
1199 /* NAME - CST1 > NAME - CST2, if CST1 < CST2. Notice that
1200 C1 and C2 are swapped in the call to compare_values. */
1201 return compare_values_warnv (c2
, c1
, strict_overflow_p
);
1207 /* We cannot compare non-constants. */
1208 if (!is_gimple_min_invariant (val1
) || !is_gimple_min_invariant (val2
))
1211 if (!POINTER_TYPE_P (TREE_TYPE (val1
)))
1213 /* We cannot compare overflowed values, except for overflow
1215 if (TREE_OVERFLOW (val1
) || TREE_OVERFLOW (val2
))
1217 if (strict_overflow_p
!= NULL
)
1218 *strict_overflow_p
= true;
1219 if (is_negative_overflow_infinity (val1
))
1220 return is_negative_overflow_infinity (val2
) ? 0 : -1;
1221 else if (is_negative_overflow_infinity (val2
))
1223 else if (is_positive_overflow_infinity (val1
))
1224 return is_positive_overflow_infinity (val2
) ? 0 : 1;
1225 else if (is_positive_overflow_infinity (val2
))
1230 return tree_int_cst_compare (val1
, val2
);
1236 /* First see if VAL1 and VAL2 are not the same. */
1237 if (val1
== val2
|| operand_equal_p (val1
, val2
, 0))
1240 /* If VAL1 is a lower address than VAL2, return -1. */
1241 if (operand_less_p (val1
, val2
) == 1)
1244 /* If VAL1 is a higher address than VAL2, return +1. */
1245 if (operand_less_p (val2
, val1
) == 1)
1248 /* If VAL1 is different than VAL2, return +2.
1249 For integer constants we either have already returned -1 or 1
1250 or they are equivalent. We still might succeed in proving
1251 something about non-trivial operands. */
1252 if (TREE_CODE (val1
) != INTEGER_CST
1253 || TREE_CODE (val2
) != INTEGER_CST
)
1255 t
= fold_binary_to_constant (NE_EXPR
, boolean_type_node
, val1
, val2
);
1256 if (t
&& integer_onep (t
))
1264 /* Compare values like compare_values_warnv, but treat comparisons of
1265 nonconstants which rely on undefined overflow as incomparable. */
1268 compare_values (tree val1
, tree val2
)
1274 ret
= compare_values_warnv (val1
, val2
, &sop
);
1276 && (!is_gimple_min_invariant (val1
) || !is_gimple_min_invariant (val2
)))
1282 /* Return 1 if VAL is inside value range VR (VR->MIN <= VAL <= VR->MAX),
1283 0 if VAL is not inside VR,
1284 -2 if we cannot tell either way.
1286 FIXME, the current semantics of this functions are a bit quirky
1287 when taken in the context of VRP. In here we do not care
1288 about VR's type. If VR is the anti-range ~[3, 5] the call
1289 value_inside_range (4, VR) will return 1.
1291 This is counter-intuitive in a strict sense, but the callers
1292 currently expect this. They are calling the function
1293 merely to determine whether VR->MIN <= VAL <= VR->MAX. The
1294 callers are applying the VR_RANGE/VR_ANTI_RANGE semantics
1297 This also applies to value_ranges_intersect_p and
1298 range_includes_zero_p. The semantics of VR_RANGE and
1299 VR_ANTI_RANGE should be encoded here, but that also means
1300 adapting the users of these functions to the new semantics.
1302 Benchmark compile/20001226-1.c compilation time after changing this
1306 value_inside_range (tree val
, value_range_t
* vr
)
1310 cmp1
= operand_less_p (val
, vr
->min
);
1316 cmp2
= operand_less_p (vr
->max
, val
);
1324 /* Return true if value ranges VR0 and VR1 have a non-empty
1327 Benchmark compile/20001226-1.c compilation time after changing this
1332 value_ranges_intersect_p (value_range_t
*vr0
, value_range_t
*vr1
)
1334 /* The value ranges do not intersect if the maximum of the first range is
1335 less than the minimum of the second range or vice versa.
1336 When those relations are unknown, we can't do any better. */
1337 if (operand_less_p (vr0
->max
, vr1
->min
) != 0)
1339 if (operand_less_p (vr1
->max
, vr0
->min
) != 0)
1345 /* Return true if VR includes the value zero, false otherwise. FIXME,
1346 currently this will return false for an anti-range like ~[-4, 3].
1347 This will be wrong when the semantics of value_inside_range are
1348 modified (currently the users of this function expect these
1352 range_includes_zero_p (value_range_t
*vr
)
1356 gcc_assert (vr
->type
!= VR_UNDEFINED
1357 && vr
->type
!= VR_VARYING
1358 && !symbolic_range_p (vr
));
1360 zero
= build_int_cst (TREE_TYPE (vr
->min
), 0);
1361 return (value_inside_range (zero
, vr
) == 1);
1364 /* Return true if T, an SSA_NAME, is known to be nonnegative. Return
1365 false otherwise or if no value range information is available. */
1368 ssa_name_nonnegative_p (const_tree t
)
1370 value_range_t
*vr
= get_value_range (t
);
1372 if (INTEGRAL_TYPE_P (t
)
1373 && TYPE_UNSIGNED (t
))
1379 /* Testing for VR_ANTI_RANGE is not useful here as any anti-range
1380 which would return a useful value should be encoded as a VR_RANGE. */
1381 if (vr
->type
== VR_RANGE
)
1383 int result
= compare_values (vr
->min
, integer_zero_node
);
1385 return (result
== 0 || result
== 1);
1390 /* If OP has a value range with a single constant value return that,
1391 otherwise return NULL_TREE. This returns OP itself if OP is a
1395 op_with_constant_singleton_value_range (tree op
)
1399 if (is_gimple_min_invariant (op
))
1402 if (TREE_CODE (op
) != SSA_NAME
)
1405 vr
= get_value_range (op
);
1406 if (vr
->type
== VR_RANGE
1407 && operand_equal_p (vr
->min
, vr
->max
, 0)
1408 && is_gimple_min_invariant (vr
->min
))
1415 /* Extract value range information from an ASSERT_EXPR EXPR and store
1419 extract_range_from_assert (value_range_t
*vr_p
, tree expr
)
1421 tree var
, cond
, limit
, min
, max
, type
;
1422 value_range_t
*var_vr
, *limit_vr
;
1423 enum tree_code cond_code
;
1425 var
= ASSERT_EXPR_VAR (expr
);
1426 cond
= ASSERT_EXPR_COND (expr
);
1428 gcc_assert (COMPARISON_CLASS_P (cond
));
1430 /* Find VAR in the ASSERT_EXPR conditional. */
1431 if (var
== TREE_OPERAND (cond
, 0)
1432 || TREE_CODE (TREE_OPERAND (cond
, 0)) == PLUS_EXPR
1433 || TREE_CODE (TREE_OPERAND (cond
, 0)) == NOP_EXPR
)
1435 /* If the predicate is of the form VAR COMP LIMIT, then we just
1436 take LIMIT from the RHS and use the same comparison code. */
1437 cond_code
= TREE_CODE (cond
);
1438 limit
= TREE_OPERAND (cond
, 1);
1439 cond
= TREE_OPERAND (cond
, 0);
1443 /* If the predicate is of the form LIMIT COMP VAR, then we need
1444 to flip around the comparison code to create the proper range
1446 cond_code
= swap_tree_comparison (TREE_CODE (cond
));
1447 limit
= TREE_OPERAND (cond
, 0);
1448 cond
= TREE_OPERAND (cond
, 1);
1451 limit
= avoid_overflow_infinity (limit
);
1453 type
= TREE_TYPE (limit
);
1454 gcc_assert (limit
!= var
);
1456 /* For pointer arithmetic, we only keep track of pointer equality
1458 if (POINTER_TYPE_P (type
) && cond_code
!= NE_EXPR
&& cond_code
!= EQ_EXPR
)
1460 set_value_range_to_varying (vr_p
);
1464 /* If LIMIT is another SSA name and LIMIT has a range of its own,
1465 try to use LIMIT's range to avoid creating symbolic ranges
1467 limit_vr
= (TREE_CODE (limit
) == SSA_NAME
) ? get_value_range (limit
) : NULL
;
1469 /* LIMIT's range is only interesting if it has any useful information. */
1471 && (limit_vr
->type
== VR_UNDEFINED
1472 || limit_vr
->type
== VR_VARYING
1473 || symbolic_range_p (limit_vr
)))
1476 /* Initially, the new range has the same set of equivalences of
1477 VAR's range. This will be revised before returning the final
1478 value. Since assertions may be chained via mutually exclusive
1479 predicates, we will need to trim the set of equivalences before
1481 gcc_assert (vr_p
->equiv
== NULL
);
1482 add_equivalence (&vr_p
->equiv
, var
);
1484 /* Extract a new range based on the asserted comparison for VAR and
1485 LIMIT's value range. Notice that if LIMIT has an anti-range, we
1486 will only use it for equality comparisons (EQ_EXPR). For any
1487 other kind of assertion, we cannot derive a range from LIMIT's
1488 anti-range that can be used to describe the new range. For
1489 instance, ASSERT_EXPR <x_2, x_2 <= b_4>. If b_4 is ~[2, 10],
1490 then b_4 takes on the ranges [-INF, 1] and [11, +INF]. There is
1491 no single range for x_2 that could describe LE_EXPR, so we might
1492 as well build the range [b_4, +INF] for it.
1493 One special case we handle is extracting a range from a
1494 range test encoded as (unsigned)var + CST <= limit. */
1495 if (TREE_CODE (cond
) == NOP_EXPR
1496 || TREE_CODE (cond
) == PLUS_EXPR
)
1498 if (TREE_CODE (cond
) == PLUS_EXPR
)
1500 min
= fold_build1 (NEGATE_EXPR
, TREE_TYPE (TREE_OPERAND (cond
, 1)),
1501 TREE_OPERAND (cond
, 1));
1502 max
= int_const_binop (PLUS_EXPR
, limit
, min
, 0);
1503 cond
= TREE_OPERAND (cond
, 0);
1507 min
= build_int_cst (TREE_TYPE (var
), 0);
1511 /* Make sure to not set TREE_OVERFLOW on the final type
1512 conversion. We are willingly interpreting large positive
1513 unsigned values as negative singed values here. */
1514 min
= force_fit_type_double (TREE_TYPE (var
), tree_to_double_int (min
),
1516 max
= force_fit_type_double (TREE_TYPE (var
), tree_to_double_int (max
),
1519 /* We can transform a max, min range to an anti-range or
1520 vice-versa. Use set_and_canonicalize_value_range which does
1522 if (cond_code
== LE_EXPR
)
1523 set_and_canonicalize_value_range (vr_p
, VR_RANGE
,
1524 min
, max
, vr_p
->equiv
);
1525 else if (cond_code
== GT_EXPR
)
1526 set_and_canonicalize_value_range (vr_p
, VR_ANTI_RANGE
,
1527 min
, max
, vr_p
->equiv
);
1531 else if (cond_code
== EQ_EXPR
)
1533 enum value_range_type range_type
;
1537 range_type
= limit_vr
->type
;
1538 min
= limit_vr
->min
;
1539 max
= limit_vr
->max
;
1543 range_type
= VR_RANGE
;
1548 set_value_range (vr_p
, range_type
, min
, max
, vr_p
->equiv
);
1550 /* When asserting the equality VAR == LIMIT and LIMIT is another
1551 SSA name, the new range will also inherit the equivalence set
1553 if (TREE_CODE (limit
) == SSA_NAME
)
1554 add_equivalence (&vr_p
->equiv
, limit
);
1556 else if (cond_code
== NE_EXPR
)
1558 /* As described above, when LIMIT's range is an anti-range and
1559 this assertion is an inequality (NE_EXPR), then we cannot
1560 derive anything from the anti-range. For instance, if
1561 LIMIT's range was ~[0, 0], the assertion 'VAR != LIMIT' does
1562 not imply that VAR's range is [0, 0]. So, in the case of
1563 anti-ranges, we just assert the inequality using LIMIT and
1566 If LIMIT_VR is a range, we can only use it to build a new
1567 anti-range if LIMIT_VR is a single-valued range. For
1568 instance, if LIMIT_VR is [0, 1], the predicate
1569 VAR != [0, 1] does not mean that VAR's range is ~[0, 1].
1570 Rather, it means that for value 0 VAR should be ~[0, 0]
1571 and for value 1, VAR should be ~[1, 1]. We cannot
1572 represent these ranges.
1574 The only situation in which we can build a valid
1575 anti-range is when LIMIT_VR is a single-valued range
1576 (i.e., LIMIT_VR->MIN == LIMIT_VR->MAX). In that case,
1577 build the anti-range ~[LIMIT_VR->MIN, LIMIT_VR->MAX]. */
1579 && limit_vr
->type
== VR_RANGE
1580 && compare_values (limit_vr
->min
, limit_vr
->max
) == 0)
1582 min
= limit_vr
->min
;
1583 max
= limit_vr
->max
;
1587 /* In any other case, we cannot use LIMIT's range to build a
1588 valid anti-range. */
1592 /* If MIN and MAX cover the whole range for their type, then
1593 just use the original LIMIT. */
1594 if (INTEGRAL_TYPE_P (type
)
1595 && vrp_val_is_min (min
)
1596 && vrp_val_is_max (max
))
1599 set_value_range (vr_p
, VR_ANTI_RANGE
, min
, max
, vr_p
->equiv
);
1601 else if (cond_code
== LE_EXPR
|| cond_code
== LT_EXPR
)
1603 min
= TYPE_MIN_VALUE (type
);
1605 if (limit_vr
== NULL
|| limit_vr
->type
== VR_ANTI_RANGE
)
1609 /* If LIMIT_VR is of the form [N1, N2], we need to build the
1610 range [MIN, N2] for LE_EXPR and [MIN, N2 - 1] for
1612 max
= limit_vr
->max
;
1615 /* If the maximum value forces us to be out of bounds, simply punt.
1616 It would be pointless to try and do anything more since this
1617 all should be optimized away above us. */
1618 if ((cond_code
== LT_EXPR
1619 && compare_values (max
, min
) == 0)
1620 || (CONSTANT_CLASS_P (max
) && TREE_OVERFLOW (max
)))
1621 set_value_range_to_varying (vr_p
);
1624 /* For LT_EXPR, we create the range [MIN, MAX - 1]. */
1625 if (cond_code
== LT_EXPR
)
1627 tree one
= build_int_cst (type
, 1);
1628 max
= fold_build2 (MINUS_EXPR
, type
, max
, one
);
1630 TREE_NO_WARNING (max
) = 1;
1633 set_value_range (vr_p
, VR_RANGE
, min
, max
, vr_p
->equiv
);
1636 else if (cond_code
== GE_EXPR
|| cond_code
== GT_EXPR
)
1638 max
= TYPE_MAX_VALUE (type
);
1640 if (limit_vr
== NULL
|| limit_vr
->type
== VR_ANTI_RANGE
)
1644 /* If LIMIT_VR is of the form [N1, N2], we need to build the
1645 range [N1, MAX] for GE_EXPR and [N1 + 1, MAX] for
1647 min
= limit_vr
->min
;
1650 /* If the minimum value forces us to be out of bounds, simply punt.
1651 It would be pointless to try and do anything more since this
1652 all should be optimized away above us. */
1653 if ((cond_code
== GT_EXPR
1654 && compare_values (min
, max
) == 0)
1655 || (CONSTANT_CLASS_P (min
) && TREE_OVERFLOW (min
)))
1656 set_value_range_to_varying (vr_p
);
1659 /* For GT_EXPR, we create the range [MIN + 1, MAX]. */
1660 if (cond_code
== GT_EXPR
)
1662 tree one
= build_int_cst (type
, 1);
1663 min
= fold_build2 (PLUS_EXPR
, type
, min
, one
);
1665 TREE_NO_WARNING (min
) = 1;
1668 set_value_range (vr_p
, VR_RANGE
, min
, max
, vr_p
->equiv
);
1674 /* If VAR already had a known range, it may happen that the new
1675 range we have computed and VAR's range are not compatible. For
1679 p_6 = ASSERT_EXPR <p_5, p_5 == NULL>;
1681 p_8 = ASSERT_EXPR <p_6, p_6 != NULL>;
1683 While the above comes from a faulty program, it will cause an ICE
1684 later because p_8 and p_6 will have incompatible ranges and at
1685 the same time will be considered equivalent. A similar situation
1689 i_6 = ASSERT_EXPR <i_5, i_5 > 10>;
1691 i_7 = ASSERT_EXPR <i_6, i_6 < 5>;
1693 Again i_6 and i_7 will have incompatible ranges. It would be
1694 pointless to try and do anything with i_7's range because
1695 anything dominated by 'if (i_5 < 5)' will be optimized away.
1696 Note, due to the wa in which simulation proceeds, the statement
1697 i_7 = ASSERT_EXPR <...> we would never be visited because the
1698 conditional 'if (i_5 < 5)' always evaluates to false. However,
1699 this extra check does not hurt and may protect against future
1700 changes to VRP that may get into a situation similar to the
1701 NULL pointer dereference example.
1703 Note that these compatibility tests are only needed when dealing
1704 with ranges or a mix of range and anti-range. If VAR_VR and VR_P
1705 are both anti-ranges, they will always be compatible, because two
1706 anti-ranges will always have a non-empty intersection. */
1708 var_vr
= get_value_range (var
);
1710 /* We may need to make adjustments when VR_P and VAR_VR are numeric
1711 ranges or anti-ranges. */
1712 if (vr_p
->type
== VR_VARYING
1713 || vr_p
->type
== VR_UNDEFINED
1714 || var_vr
->type
== VR_VARYING
1715 || var_vr
->type
== VR_UNDEFINED
1716 || symbolic_range_p (vr_p
)
1717 || symbolic_range_p (var_vr
))
1720 if (var_vr
->type
== VR_RANGE
&& vr_p
->type
== VR_RANGE
)
1722 /* If the two ranges have a non-empty intersection, we can
1723 refine the resulting range. Since the assert expression
1724 creates an equivalency and at the same time it asserts a
1725 predicate, we can take the intersection of the two ranges to
1726 get better precision. */
1727 if (value_ranges_intersect_p (var_vr
, vr_p
))
1729 /* Use the larger of the two minimums. */
1730 if (compare_values (vr_p
->min
, var_vr
->min
) == -1)
1735 /* Use the smaller of the two maximums. */
1736 if (compare_values (vr_p
->max
, var_vr
->max
) == 1)
1741 set_value_range (vr_p
, vr_p
->type
, min
, max
, vr_p
->equiv
);
1745 /* The two ranges do not intersect, set the new range to
1746 VARYING, because we will not be able to do anything
1747 meaningful with it. */
1748 set_value_range_to_varying (vr_p
);
1751 else if ((var_vr
->type
== VR_RANGE
&& vr_p
->type
== VR_ANTI_RANGE
)
1752 || (var_vr
->type
== VR_ANTI_RANGE
&& vr_p
->type
== VR_RANGE
))
1754 /* A range and an anti-range will cancel each other only if
1755 their ends are the same. For instance, in the example above,
1756 p_8's range ~[0, 0] and p_6's range [0, 0] are incompatible,
1757 so VR_P should be set to VR_VARYING. */
1758 if (compare_values (var_vr
->min
, vr_p
->min
) == 0
1759 && compare_values (var_vr
->max
, vr_p
->max
) == 0)
1760 set_value_range_to_varying (vr_p
);
1763 tree min
, max
, anti_min
, anti_max
, real_min
, real_max
;
1766 /* We want to compute the logical AND of the two ranges;
1767 there are three cases to consider.
1770 1. The VR_ANTI_RANGE range is completely within the
1771 VR_RANGE and the endpoints of the ranges are
1772 different. In that case the resulting range
1773 should be whichever range is more precise.
1774 Typically that will be the VR_RANGE.
1776 2. The VR_ANTI_RANGE is completely disjoint from
1777 the VR_RANGE. In this case the resulting range
1778 should be the VR_RANGE.
1780 3. There is some overlap between the VR_ANTI_RANGE
1783 3a. If the high limit of the VR_ANTI_RANGE resides
1784 within the VR_RANGE, then the result is a new
1785 VR_RANGE starting at the high limit of the
1786 VR_ANTI_RANGE + 1 and extending to the
1787 high limit of the original VR_RANGE.
1789 3b. If the low limit of the VR_ANTI_RANGE resides
1790 within the VR_RANGE, then the result is a new
1791 VR_RANGE starting at the low limit of the original
1792 VR_RANGE and extending to the low limit of the
1793 VR_ANTI_RANGE - 1. */
1794 if (vr_p
->type
== VR_ANTI_RANGE
)
1796 anti_min
= vr_p
->min
;
1797 anti_max
= vr_p
->max
;
1798 real_min
= var_vr
->min
;
1799 real_max
= var_vr
->max
;
1803 anti_min
= var_vr
->min
;
1804 anti_max
= var_vr
->max
;
1805 real_min
= vr_p
->min
;
1806 real_max
= vr_p
->max
;
1810 /* Case 1, VR_ANTI_RANGE completely within VR_RANGE,
1811 not including any endpoints. */
1812 if (compare_values (anti_max
, real_max
) == -1
1813 && compare_values (anti_min
, real_min
) == 1)
1815 /* If the range is covering the whole valid range of
1816 the type keep the anti-range. */
1817 if (!vrp_val_is_min (real_min
)
1818 || !vrp_val_is_max (real_max
))
1819 set_value_range (vr_p
, VR_RANGE
, real_min
,
1820 real_max
, vr_p
->equiv
);
1822 /* Case 2, VR_ANTI_RANGE completely disjoint from
1824 else if (compare_values (anti_min
, real_max
) == 1
1825 || compare_values (anti_max
, real_min
) == -1)
1827 set_value_range (vr_p
, VR_RANGE
, real_min
,
1828 real_max
, vr_p
->equiv
);
1830 /* Case 3a, the anti-range extends into the low
1831 part of the real range. Thus creating a new
1832 low for the real range. */
1833 else if (((cmp
= compare_values (anti_max
, real_min
)) == 1
1835 && compare_values (anti_max
, real_max
) == -1)
1837 gcc_assert (!is_positive_overflow_infinity (anti_max
));
1838 if (needs_overflow_infinity (TREE_TYPE (anti_max
))
1839 && vrp_val_is_max (anti_max
))
1841 if (!supports_overflow_infinity (TREE_TYPE (var_vr
->min
)))
1843 set_value_range_to_varying (vr_p
);
1846 min
= positive_overflow_infinity (TREE_TYPE (var_vr
->min
));
1848 else if (!POINTER_TYPE_P (TREE_TYPE (var_vr
->min
)))
1849 min
= fold_build2 (PLUS_EXPR
, TREE_TYPE (var_vr
->min
),
1851 build_int_cst (TREE_TYPE (var_vr
->min
), 1));
1853 min
= fold_build2 (POINTER_PLUS_EXPR
, TREE_TYPE (var_vr
->min
),
1854 anti_max
, size_int (1));
1856 set_value_range (vr_p
, VR_RANGE
, min
, max
, vr_p
->equiv
);
1858 /* Case 3b, the anti-range extends into the high
1859 part of the real range. Thus creating a new
1860 higher for the real range. */
1861 else if (compare_values (anti_min
, real_min
) == 1
1862 && ((cmp
= compare_values (anti_min
, real_max
)) == -1
1865 gcc_assert (!is_negative_overflow_infinity (anti_min
));
1866 if (needs_overflow_infinity (TREE_TYPE (anti_min
))
1867 && vrp_val_is_min (anti_min
))
1869 if (!supports_overflow_infinity (TREE_TYPE (var_vr
->min
)))
1871 set_value_range_to_varying (vr_p
);
1874 max
= negative_overflow_infinity (TREE_TYPE (var_vr
->min
));
1876 else if (!POINTER_TYPE_P (TREE_TYPE (var_vr
->min
)))
1877 max
= fold_build2 (MINUS_EXPR
, TREE_TYPE (var_vr
->min
),
1879 build_int_cst (TREE_TYPE (var_vr
->min
), 1));
1881 max
= fold_build2 (POINTER_PLUS_EXPR
, TREE_TYPE (var_vr
->min
),
1885 set_value_range (vr_p
, VR_RANGE
, min
, max
, vr_p
->equiv
);
1892 /* Extract range information from SSA name VAR and store it in VR. If
1893 VAR has an interesting range, use it. Otherwise, create the
1894 range [VAR, VAR] and return it. This is useful in situations where
1895 we may have conditionals testing values of VARYING names. For
1902 Even if y_5 is deemed VARYING, we can determine that x_3 > y_5 is
1906 extract_range_from_ssa_name (value_range_t
*vr
, tree var
)
1908 value_range_t
*var_vr
= get_value_range (var
);
1910 if (var_vr
->type
!= VR_UNDEFINED
&& var_vr
->type
!= VR_VARYING
)
1911 copy_value_range (vr
, var_vr
);
1913 set_value_range (vr
, VR_RANGE
, var
, var
, NULL
);
1915 add_equivalence (&vr
->equiv
, var
);
1919 /* Wrapper around int_const_binop. If the operation overflows and we
1920 are not using wrapping arithmetic, then adjust the result to be
1921 -INF or +INF depending on CODE, VAL1 and VAL2. This can return
1922 NULL_TREE if we need to use an overflow infinity representation but
1923 the type does not support it. */
1926 vrp_int_const_binop (enum tree_code code
, tree val1
, tree val2
)
1930 res
= int_const_binop (code
, val1
, val2
, 0);
1932 /* If we are using unsigned arithmetic, operate symbolically
1933 on -INF and +INF as int_const_binop only handles signed overflow. */
1934 if (TYPE_UNSIGNED (TREE_TYPE (val1
)))
1936 int checkz
= compare_values (res
, val1
);
1937 bool overflow
= false;
1939 /* Ensure that res = val1 [+*] val2 >= val1
1940 or that res = val1 - val2 <= val1. */
1941 if ((code
== PLUS_EXPR
1942 && !(checkz
== 1 || checkz
== 0))
1943 || (code
== MINUS_EXPR
1944 && !(checkz
== 0 || checkz
== -1)))
1948 /* Checking for multiplication overflow is done by dividing the
1949 output of the multiplication by the first input of the
1950 multiplication. If the result of that division operation is
1951 not equal to the second input of the multiplication, then the
1952 multiplication overflowed. */
1953 else if (code
== MULT_EXPR
&& !integer_zerop (val1
))
1955 tree tmp
= int_const_binop (TRUNC_DIV_EXPR
,
1958 int check
= compare_values (tmp
, val2
);
1966 res
= copy_node (res
);
1967 TREE_OVERFLOW (res
) = 1;
1971 else if (TYPE_OVERFLOW_WRAPS (TREE_TYPE (val1
)))
1972 /* If the singed operation wraps then int_const_binop has done
1973 everything we want. */
1975 else if ((TREE_OVERFLOW (res
)
1976 && !TREE_OVERFLOW (val1
)
1977 && !TREE_OVERFLOW (val2
))
1978 || is_overflow_infinity (val1
)
1979 || is_overflow_infinity (val2
))
1981 /* If the operation overflowed but neither VAL1 nor VAL2 are
1982 overflown, return -INF or +INF depending on the operation
1983 and the combination of signs of the operands. */
1984 int sgn1
= tree_int_cst_sgn (val1
);
1985 int sgn2
= tree_int_cst_sgn (val2
);
1987 if (needs_overflow_infinity (TREE_TYPE (res
))
1988 && !supports_overflow_infinity (TREE_TYPE (res
)))
1991 /* We have to punt on adding infinities of different signs,
1992 since we can't tell what the sign of the result should be.
1993 Likewise for subtracting infinities of the same sign. */
1994 if (((code
== PLUS_EXPR
&& sgn1
!= sgn2
)
1995 || (code
== MINUS_EXPR
&& sgn1
== sgn2
))
1996 && is_overflow_infinity (val1
)
1997 && is_overflow_infinity (val2
))
2000 /* Don't try to handle division or shifting of infinities. */
2001 if ((code
== TRUNC_DIV_EXPR
2002 || code
== FLOOR_DIV_EXPR
2003 || code
== CEIL_DIV_EXPR
2004 || code
== EXACT_DIV_EXPR
2005 || code
== ROUND_DIV_EXPR
2006 || code
== RSHIFT_EXPR
)
2007 && (is_overflow_infinity (val1
)
2008 || is_overflow_infinity (val2
)))
2011 /* Notice that we only need to handle the restricted set of
2012 operations handled by extract_range_from_binary_expr.
2013 Among them, only multiplication, addition and subtraction
2014 can yield overflow without overflown operands because we
2015 are working with integral types only... except in the
2016 case VAL1 = -INF and VAL2 = -1 which overflows to +INF
2017 for division too. */
2019 /* For multiplication, the sign of the overflow is given
2020 by the comparison of the signs of the operands. */
2021 if ((code
== MULT_EXPR
&& sgn1
== sgn2
)
2022 /* For addition, the operands must be of the same sign
2023 to yield an overflow. Its sign is therefore that
2024 of one of the operands, for example the first. For
2025 infinite operands X + -INF is negative, not positive. */
2026 || (code
== PLUS_EXPR
2028 ? !is_negative_overflow_infinity (val2
)
2029 : is_positive_overflow_infinity (val2
)))
2030 /* For subtraction, non-infinite operands must be of
2031 different signs to yield an overflow. Its sign is
2032 therefore that of the first operand or the opposite of
2033 that of the second operand. A first operand of 0 counts
2034 as positive here, for the corner case 0 - (-INF), which
2035 overflows, but must yield +INF. For infinite operands 0
2036 - INF is negative, not positive. */
2037 || (code
== MINUS_EXPR
2039 ? !is_positive_overflow_infinity (val2
)
2040 : is_negative_overflow_infinity (val2
)))
2041 /* We only get in here with positive shift count, so the
2042 overflow direction is the same as the sign of val1.
2043 Actually rshift does not overflow at all, but we only
2044 handle the case of shifting overflowed -INF and +INF. */
2045 || (code
== RSHIFT_EXPR
2047 /* For division, the only case is -INF / -1 = +INF. */
2048 || code
== TRUNC_DIV_EXPR
2049 || code
== FLOOR_DIV_EXPR
2050 || code
== CEIL_DIV_EXPR
2051 || code
== EXACT_DIV_EXPR
2052 || code
== ROUND_DIV_EXPR
)
2053 return (needs_overflow_infinity (TREE_TYPE (res
))
2054 ? positive_overflow_infinity (TREE_TYPE (res
))
2055 : TYPE_MAX_VALUE (TREE_TYPE (res
)));
2057 return (needs_overflow_infinity (TREE_TYPE (res
))
2058 ? negative_overflow_infinity (TREE_TYPE (res
))
2059 : TYPE_MIN_VALUE (TREE_TYPE (res
)));
2066 /* Extract range information from a binary expression EXPR based on
2067 the ranges of each of its operands and the expression code. */
2070 extract_range_from_binary_expr (value_range_t
*vr
,
2071 enum tree_code code
,
2072 tree expr_type
, tree op0
, tree op1
)
2074 enum value_range_type type
;
2077 value_range_t vr0
= { VR_UNDEFINED
, NULL_TREE
, NULL_TREE
, NULL
};
2078 value_range_t vr1
= { VR_UNDEFINED
, NULL_TREE
, NULL_TREE
, NULL
};
2080 /* Not all binary expressions can be applied to ranges in a
2081 meaningful way. Handle only arithmetic operations. */
2082 if (code
!= PLUS_EXPR
2083 && code
!= MINUS_EXPR
2084 && code
!= POINTER_PLUS_EXPR
2085 && code
!= MULT_EXPR
2086 && code
!= TRUNC_DIV_EXPR
2087 && code
!= FLOOR_DIV_EXPR
2088 && code
!= CEIL_DIV_EXPR
2089 && code
!= EXACT_DIV_EXPR
2090 && code
!= ROUND_DIV_EXPR
2091 && code
!= TRUNC_MOD_EXPR
2092 && code
!= RSHIFT_EXPR
2095 && code
!= BIT_AND_EXPR
2096 && code
!= BIT_IOR_EXPR
2097 && code
!= TRUTH_AND_EXPR
2098 && code
!= TRUTH_OR_EXPR
)
2100 /* We can still do constant propagation here. */
2101 tree const_op0
= op_with_constant_singleton_value_range (op0
);
2102 tree const_op1
= op_with_constant_singleton_value_range (op1
);
2103 if (const_op0
|| const_op1
)
2105 tree tem
= fold_binary (code
, expr_type
,
2106 const_op0
? const_op0
: op0
,
2107 const_op1
? const_op1
: op1
);
2109 && is_gimple_min_invariant (tem
)
2110 && !is_overflow_infinity (tem
))
2112 set_value_range (vr
, VR_RANGE
, tem
, tem
, NULL
);
2116 set_value_range_to_varying (vr
);
2120 /* Get value ranges for each operand. For constant operands, create
2121 a new value range with the operand to simplify processing. */
2122 if (TREE_CODE (op0
) == SSA_NAME
)
2123 vr0
= *(get_value_range (op0
));
2124 else if (is_gimple_min_invariant (op0
))
2125 set_value_range_to_value (&vr0
, op0
, NULL
);
2127 set_value_range_to_varying (&vr0
);
2129 if (TREE_CODE (op1
) == SSA_NAME
)
2130 vr1
= *(get_value_range (op1
));
2131 else if (is_gimple_min_invariant (op1
))
2132 set_value_range_to_value (&vr1
, op1
, NULL
);
2134 set_value_range_to_varying (&vr1
);
2136 /* If either range is UNDEFINED, so is the result. */
2137 if (vr0
.type
== VR_UNDEFINED
|| vr1
.type
== VR_UNDEFINED
)
2139 set_value_range_to_undefined (vr
);
2143 /* The type of the resulting value range defaults to VR0.TYPE. */
2146 /* Refuse to operate on VARYING ranges, ranges of different kinds
2147 and symbolic ranges. As an exception, we allow BIT_AND_EXPR
2148 because we may be able to derive a useful range even if one of
2149 the operands is VR_VARYING or symbolic range. Similarly for
2150 divisions. TODO, we may be able to derive anti-ranges in
2152 if (code
!= BIT_AND_EXPR
2153 && code
!= TRUTH_AND_EXPR
2154 && code
!= TRUTH_OR_EXPR
2155 && code
!= TRUNC_DIV_EXPR
2156 && code
!= FLOOR_DIV_EXPR
2157 && code
!= CEIL_DIV_EXPR
2158 && code
!= EXACT_DIV_EXPR
2159 && code
!= ROUND_DIV_EXPR
2160 && code
!= TRUNC_MOD_EXPR
2161 && (vr0
.type
== VR_VARYING
2162 || vr1
.type
== VR_VARYING
2163 || vr0
.type
!= vr1
.type
2164 || symbolic_range_p (&vr0
)
2165 || symbolic_range_p (&vr1
)))
2167 set_value_range_to_varying (vr
);
2171 /* Now evaluate the expression to determine the new range. */
2172 if (POINTER_TYPE_P (expr_type
)
2173 || POINTER_TYPE_P (TREE_TYPE (op0
))
2174 || POINTER_TYPE_P (TREE_TYPE (op1
)))
2176 if (code
== MIN_EXPR
|| code
== MAX_EXPR
)
2178 /* For MIN/MAX expressions with pointers, we only care about
2179 nullness, if both are non null, then the result is nonnull.
2180 If both are null, then the result is null. Otherwise they
2182 if (range_is_nonnull (&vr0
) && range_is_nonnull (&vr1
))
2183 set_value_range_to_nonnull (vr
, expr_type
);
2184 else if (range_is_null (&vr0
) && range_is_null (&vr1
))
2185 set_value_range_to_null (vr
, expr_type
);
2187 set_value_range_to_varying (vr
);
2191 if (code
== POINTER_PLUS_EXPR
)
2193 /* For pointer types, we are really only interested in asserting
2194 whether the expression evaluates to non-NULL. */
2195 if (range_is_nonnull (&vr0
) || range_is_nonnull (&vr1
))
2196 set_value_range_to_nonnull (vr
, expr_type
);
2197 else if (range_is_null (&vr0
) && range_is_null (&vr1
))
2198 set_value_range_to_null (vr
, expr_type
);
2200 set_value_range_to_varying (vr
);
2202 else if (code
== BIT_AND_EXPR
)
2204 /* For pointer types, we are really only interested in asserting
2205 whether the expression evaluates to non-NULL. */
2206 if (range_is_nonnull (&vr0
) && range_is_nonnull (&vr1
))
2207 set_value_range_to_nonnull (vr
, expr_type
);
2208 else if (range_is_null (&vr0
) || range_is_null (&vr1
))
2209 set_value_range_to_null (vr
, expr_type
);
2211 set_value_range_to_varying (vr
);
2219 /* For integer ranges, apply the operation to each end of the
2220 range and see what we end up with. */
2221 if (code
== TRUTH_AND_EXPR
2222 || code
== TRUTH_OR_EXPR
)
2224 /* If one of the operands is zero, we know that the whole
2225 expression evaluates zero. */
2226 if (code
== TRUTH_AND_EXPR
2227 && ((vr0
.type
== VR_RANGE
2228 && integer_zerop (vr0
.min
)
2229 && integer_zerop (vr0
.max
))
2230 || (vr1
.type
== VR_RANGE
2231 && integer_zerop (vr1
.min
)
2232 && integer_zerop (vr1
.max
))))
2235 min
= max
= build_int_cst (expr_type
, 0);
2237 /* If one of the operands is one, we know that the whole
2238 expression evaluates one. */
2239 else if (code
== TRUTH_OR_EXPR
2240 && ((vr0
.type
== VR_RANGE
2241 && integer_onep (vr0
.min
)
2242 && integer_onep (vr0
.max
))
2243 || (vr1
.type
== VR_RANGE
2244 && integer_onep (vr1
.min
)
2245 && integer_onep (vr1
.max
))))
2248 min
= max
= build_int_cst (expr_type
, 1);
2250 else if (vr0
.type
!= VR_VARYING
2251 && vr1
.type
!= VR_VARYING
2252 && vr0
.type
== vr1
.type
2253 && !symbolic_range_p (&vr0
)
2254 && !overflow_infinity_range_p (&vr0
)
2255 && !symbolic_range_p (&vr1
)
2256 && !overflow_infinity_range_p (&vr1
))
2258 /* Boolean expressions cannot be folded with int_const_binop. */
2259 min
= fold_binary (code
, expr_type
, vr0
.min
, vr1
.min
);
2260 max
= fold_binary (code
, expr_type
, vr0
.max
, vr1
.max
);
2264 /* The result of a TRUTH_*_EXPR is always true or false. */
2265 set_value_range_to_truthvalue (vr
, expr_type
);
2269 else if (code
== PLUS_EXPR
2271 || code
== MAX_EXPR
)
2273 /* If we have a PLUS_EXPR with two VR_ANTI_RANGEs, drop to
2274 VR_VARYING. It would take more effort to compute a precise
2275 range for such a case. For example, if we have op0 == 1 and
2276 op1 == -1 with their ranges both being ~[0,0], we would have
2277 op0 + op1 == 0, so we cannot claim that the sum is in ~[0,0].
2278 Note that we are guaranteed to have vr0.type == vr1.type at
2280 if (code
== PLUS_EXPR
&& vr0
.type
== VR_ANTI_RANGE
)
2282 set_value_range_to_varying (vr
);
2286 /* For operations that make the resulting range directly
2287 proportional to the original ranges, apply the operation to
2288 the same end of each range. */
2289 min
= vrp_int_const_binop (code
, vr0
.min
, vr1
.min
);
2290 max
= vrp_int_const_binop (code
, vr0
.max
, vr1
.max
);
2292 /* If both additions overflowed the range kind is still correct.
2293 This happens regularly with subtracting something in unsigned
2295 ??? See PR30318 for all the cases we do not handle. */
2296 if (code
== PLUS_EXPR
2297 && (TREE_OVERFLOW (min
) && !is_overflow_infinity (min
))
2298 && (TREE_OVERFLOW (max
) && !is_overflow_infinity (max
)))
2300 min
= build_int_cst_wide (TREE_TYPE (min
),
2301 TREE_INT_CST_LOW (min
),
2302 TREE_INT_CST_HIGH (min
));
2303 max
= build_int_cst_wide (TREE_TYPE (max
),
2304 TREE_INT_CST_LOW (max
),
2305 TREE_INT_CST_HIGH (max
));
2308 else if (code
== MULT_EXPR
2309 || code
== TRUNC_DIV_EXPR
2310 || code
== FLOOR_DIV_EXPR
2311 || code
== CEIL_DIV_EXPR
2312 || code
== EXACT_DIV_EXPR
2313 || code
== ROUND_DIV_EXPR
2314 || code
== RSHIFT_EXPR
)
2320 /* If we have an unsigned MULT_EXPR with two VR_ANTI_RANGEs,
2321 drop to VR_VARYING. It would take more effort to compute a
2322 precise range for such a case. For example, if we have
2323 op0 == 65536 and op1 == 65536 with their ranges both being
2324 ~[0,0] on a 32-bit machine, we would have op0 * op1 == 0, so
2325 we cannot claim that the product is in ~[0,0]. Note that we
2326 are guaranteed to have vr0.type == vr1.type at this
2328 if (code
== MULT_EXPR
2329 && vr0
.type
== VR_ANTI_RANGE
2330 && !TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (op0
)))
2332 set_value_range_to_varying (vr
);
2336 /* If we have a RSHIFT_EXPR with any shift values outside [0..prec-1],
2337 then drop to VR_VARYING. Outside of this range we get undefined
2338 behavior from the shift operation. We cannot even trust
2339 SHIFT_COUNT_TRUNCATED at this stage, because that applies to rtl
2340 shifts, and the operation at the tree level may be widened. */
2341 if (code
== RSHIFT_EXPR
)
2343 if (vr1
.type
== VR_ANTI_RANGE
2344 || !vrp_expr_computes_nonnegative (op1
, &sop
)
2346 (build_int_cst (TREE_TYPE (vr1
.max
),
2347 TYPE_PRECISION (expr_type
) - 1),
2350 set_value_range_to_varying (vr
);
2355 else if ((code
== TRUNC_DIV_EXPR
2356 || code
== FLOOR_DIV_EXPR
2357 || code
== CEIL_DIV_EXPR
2358 || code
== EXACT_DIV_EXPR
2359 || code
== ROUND_DIV_EXPR
)
2360 && (vr0
.type
!= VR_RANGE
|| symbolic_range_p (&vr0
)))
2362 /* For division, if op1 has VR_RANGE but op0 does not, something
2363 can be deduced just from that range. Say [min, max] / [4, max]
2364 gives [min / 4, max / 4] range. */
2365 if (vr1
.type
== VR_RANGE
2366 && !symbolic_range_p (&vr1
)
2367 && !range_includes_zero_p (&vr1
))
2369 vr0
.type
= type
= VR_RANGE
;
2370 vr0
.min
= vrp_val_min (TREE_TYPE (op0
));
2371 vr0
.max
= vrp_val_max (TREE_TYPE (op1
));
2375 set_value_range_to_varying (vr
);
2380 /* For divisions, if op0 is VR_RANGE, we can deduce a range
2381 even if op1 is VR_VARYING, VR_ANTI_RANGE, symbolic or can
2383 if ((code
== TRUNC_DIV_EXPR
2384 || code
== FLOOR_DIV_EXPR
2385 || code
== CEIL_DIV_EXPR
2386 || code
== EXACT_DIV_EXPR
2387 || code
== ROUND_DIV_EXPR
)
2388 && vr0
.type
== VR_RANGE
2389 && (vr1
.type
!= VR_RANGE
2390 || symbolic_range_p (&vr1
)
2391 || range_includes_zero_p (&vr1
)))
2393 tree zero
= build_int_cst (TREE_TYPE (vr0
.min
), 0);
2399 if (vrp_expr_computes_nonnegative (op1
, &sop
) && !sop
)
2401 /* For unsigned division or when divisor is known
2402 to be non-negative, the range has to cover
2403 all numbers from 0 to max for positive max
2404 and all numbers from min to 0 for negative min. */
2405 cmp
= compare_values (vr0
.max
, zero
);
2408 else if (cmp
== 0 || cmp
== 1)
2412 cmp
= compare_values (vr0
.min
, zero
);
2415 else if (cmp
== 0 || cmp
== -1)
2422 /* Otherwise the range is -max .. max or min .. -min
2423 depending on which bound is bigger in absolute value,
2424 as the division can change the sign. */
2425 abs_extent_range (vr
, vr0
.min
, vr0
.max
);
2428 if (type
== VR_VARYING
)
2430 set_value_range_to_varying (vr
);
2435 /* Multiplications and divisions are a bit tricky to handle,
2436 depending on the mix of signs we have in the two ranges, we
2437 need to operate on different values to get the minimum and
2438 maximum values for the new range. One approach is to figure
2439 out all the variations of range combinations and do the
2442 However, this involves several calls to compare_values and it
2443 is pretty convoluted. It's simpler to do the 4 operations
2444 (MIN0 OP MIN1, MIN0 OP MAX1, MAX0 OP MIN1 and MAX0 OP MAX0 OP
2445 MAX1) and then figure the smallest and largest values to form
2449 gcc_assert ((vr0
.type
== VR_RANGE
2450 || (code
== MULT_EXPR
&& vr0
.type
== VR_ANTI_RANGE
))
2451 && vr0
.type
== vr1
.type
);
2453 /* Compute the 4 cross operations. */
2455 val
[0] = vrp_int_const_binop (code
, vr0
.min
, vr1
.min
);
2456 if (val
[0] == NULL_TREE
)
2459 if (vr1
.max
== vr1
.min
)
2463 val
[1] = vrp_int_const_binop (code
, vr0
.min
, vr1
.max
);
2464 if (val
[1] == NULL_TREE
)
2468 if (vr0
.max
== vr0
.min
)
2472 val
[2] = vrp_int_const_binop (code
, vr0
.max
, vr1
.min
);
2473 if (val
[2] == NULL_TREE
)
2477 if (vr0
.min
== vr0
.max
|| vr1
.min
== vr1
.max
)
2481 val
[3] = vrp_int_const_binop (code
, vr0
.max
, vr1
.max
);
2482 if (val
[3] == NULL_TREE
)
2488 set_value_range_to_varying (vr
);
2492 /* Set MIN to the minimum of VAL[i] and MAX to the maximum
2496 for (i
= 1; i
< 4; i
++)
2498 if (!is_gimple_min_invariant (min
)
2499 || (TREE_OVERFLOW (min
) && !is_overflow_infinity (min
))
2500 || !is_gimple_min_invariant (max
)
2501 || (TREE_OVERFLOW (max
) && !is_overflow_infinity (max
)))
2506 if (!is_gimple_min_invariant (val
[i
])
2507 || (TREE_OVERFLOW (val
[i
])
2508 && !is_overflow_infinity (val
[i
])))
2510 /* If we found an overflowed value, set MIN and MAX
2511 to it so that we set the resulting range to
2517 if (compare_values (val
[i
], min
) == -1)
2520 if (compare_values (val
[i
], max
) == 1)
2526 else if (code
== TRUNC_MOD_EXPR
)
2529 if (vr1
.type
!= VR_RANGE
2530 || symbolic_range_p (&vr1
)
2531 || range_includes_zero_p (&vr1
)
2532 || vrp_val_is_min (vr1
.min
))
2534 set_value_range_to_varying (vr
);
2538 /* Compute MAX <|vr1.min|, |vr1.max|> - 1. */
2539 max
= fold_unary_to_constant (ABS_EXPR
, TREE_TYPE (vr1
.min
), vr1
.min
);
2540 if (tree_int_cst_lt (max
, vr1
.max
))
2542 max
= int_const_binop (MINUS_EXPR
, max
, integer_one_node
, 0);
2543 /* If the dividend is non-negative the modulus will be
2544 non-negative as well. */
2545 if (TYPE_UNSIGNED (TREE_TYPE (max
))
2546 || (vrp_expr_computes_nonnegative (op0
, &sop
) && !sop
))
2547 min
= build_int_cst (TREE_TYPE (max
), 0);
2549 min
= fold_unary_to_constant (NEGATE_EXPR
, TREE_TYPE (max
), max
);
2551 else if (code
== MINUS_EXPR
)
2553 /* If we have a MINUS_EXPR with two VR_ANTI_RANGEs, drop to
2554 VR_VARYING. It would take more effort to compute a precise
2555 range for such a case. For example, if we have op0 == 1 and
2556 op1 == 1 with their ranges both being ~[0,0], we would have
2557 op0 - op1 == 0, so we cannot claim that the difference is in
2558 ~[0,0]. Note that we are guaranteed to have
2559 vr0.type == vr1.type at this point. */
2560 if (vr0
.type
== VR_ANTI_RANGE
)
2562 set_value_range_to_varying (vr
);
2566 /* For MINUS_EXPR, apply the operation to the opposite ends of
2568 min
= vrp_int_const_binop (code
, vr0
.min
, vr1
.max
);
2569 max
= vrp_int_const_binop (code
, vr0
.max
, vr1
.min
);
2571 else if (code
== BIT_AND_EXPR
)
2573 bool vr0_int_cst_singleton_p
, vr1_int_cst_singleton_p
;
2575 vr0_int_cst_singleton_p
= range_int_cst_singleton_p (&vr0
);
2576 vr1_int_cst_singleton_p
= range_int_cst_singleton_p (&vr1
);
2578 if (vr0_int_cst_singleton_p
&& vr1_int_cst_singleton_p
)
2579 min
= max
= int_const_binop (code
, vr0
.max
, vr1
.max
, 0);
2580 else if (vr0_int_cst_singleton_p
2581 && tree_int_cst_sgn (vr0
.max
) >= 0)
2583 min
= build_int_cst (expr_type
, 0);
2586 else if (vr1_int_cst_singleton_p
2587 && tree_int_cst_sgn (vr1
.max
) >= 0)
2590 min
= build_int_cst (expr_type
, 0);
2595 set_value_range_to_varying (vr
);
2599 else if (code
== BIT_IOR_EXPR
)
2601 if (range_int_cst_p (&vr0
)
2602 && range_int_cst_p (&vr1
)
2603 && tree_int_cst_sgn (vr0
.min
) >= 0
2604 && tree_int_cst_sgn (vr1
.min
) >= 0)
2606 double_int vr0_max
= tree_to_double_int (vr0
.max
);
2607 double_int vr1_max
= tree_to_double_int (vr1
.max
);
2610 /* Set all bits to the right of the most significant one to 1.
2611 For example, [0, 4] | [4, 4] = [4, 7]. */
2612 ior_max
.low
= vr0_max
.low
| vr1_max
.low
;
2613 ior_max
.high
= vr0_max
.high
| vr1_max
.high
;
2614 if (ior_max
.high
!= 0)
2616 ior_max
.low
= ~(unsigned HOST_WIDE_INT
)0u;
2617 ior_max
.high
|= ((HOST_WIDE_INT
) 1
2618 << floor_log2 (ior_max
.high
)) - 1;
2620 else if (ior_max
.low
!= 0)
2621 ior_max
.low
|= ((unsigned HOST_WIDE_INT
) 1u
2622 << floor_log2 (ior_max
.low
)) - 1;
2624 /* Both of these endpoints are conservative. */
2625 min
= vrp_int_const_binop (MAX_EXPR
, vr0
.min
, vr1
.min
);
2626 max
= double_int_to_tree (expr_type
, ior_max
);
2630 set_value_range_to_varying (vr
);
2637 /* If either MIN or MAX overflowed, then set the resulting range to
2638 VARYING. But we do accept an overflow infinity
2640 if (min
== NULL_TREE
2641 || !is_gimple_min_invariant (min
)
2642 || (TREE_OVERFLOW (min
) && !is_overflow_infinity (min
))
2644 || !is_gimple_min_invariant (max
)
2645 || (TREE_OVERFLOW (max
) && !is_overflow_infinity (max
)))
2647 set_value_range_to_varying (vr
);
2653 2) [-INF, +-INF(OVF)]
2654 3) [+-INF(OVF), +INF]
2655 4) [+-INF(OVF), +-INF(OVF)]
2656 We learn nothing when we have INF and INF(OVF) on both sides.
2657 Note that we do accept [-INF, -INF] and [+INF, +INF] without
2659 if ((vrp_val_is_min (min
) || is_overflow_infinity (min
))
2660 && (vrp_val_is_max (max
) || is_overflow_infinity (max
)))
2662 set_value_range_to_varying (vr
);
2666 cmp
= compare_values (min
, max
);
2667 if (cmp
== -2 || cmp
== 1)
2669 /* If the new range has its limits swapped around (MIN > MAX),
2670 then the operation caused one of them to wrap around, mark
2671 the new range VARYING. */
2672 set_value_range_to_varying (vr
);
2675 set_value_range (vr
, type
, min
, max
, NULL
);
2679 /* Extract range information from a unary expression EXPR based on
2680 the range of its operand and the expression code. */
2683 extract_range_from_unary_expr (value_range_t
*vr
, enum tree_code code
,
2684 tree type
, tree op0
)
2688 value_range_t vr0
= { VR_UNDEFINED
, NULL_TREE
, NULL_TREE
, NULL
};
2690 /* Refuse to operate on certain unary expressions for which we
2691 cannot easily determine a resulting range. */
2692 if (code
== FIX_TRUNC_EXPR
2693 || code
== FLOAT_EXPR
2694 || code
== BIT_NOT_EXPR
2695 || code
== CONJ_EXPR
)
2697 /* We can still do constant propagation here. */
2698 if ((op0
= op_with_constant_singleton_value_range (op0
)) != NULL_TREE
)
2700 tree tem
= fold_unary (code
, type
, op0
);
2702 && is_gimple_min_invariant (tem
)
2703 && !is_overflow_infinity (tem
))
2705 set_value_range (vr
, VR_RANGE
, tem
, tem
, NULL
);
2709 set_value_range_to_varying (vr
);
2713 /* Get value ranges for the operand. For constant operands, create
2714 a new value range with the operand to simplify processing. */
2715 if (TREE_CODE (op0
) == SSA_NAME
)
2716 vr0
= *(get_value_range (op0
));
2717 else if (is_gimple_min_invariant (op0
))
2718 set_value_range_to_value (&vr0
, op0
, NULL
);
2720 set_value_range_to_varying (&vr0
);
2722 /* If VR0 is UNDEFINED, so is the result. */
2723 if (vr0
.type
== VR_UNDEFINED
)
2725 set_value_range_to_undefined (vr
);
2729 /* Refuse to operate on symbolic ranges, or if neither operand is
2730 a pointer or integral type. */
2731 if ((!INTEGRAL_TYPE_P (TREE_TYPE (op0
))
2732 && !POINTER_TYPE_P (TREE_TYPE (op0
)))
2733 || (vr0
.type
!= VR_VARYING
2734 && symbolic_range_p (&vr0
)))
2736 set_value_range_to_varying (vr
);
2740 /* If the expression involves pointers, we are only interested in
2741 determining if it evaluates to NULL [0, 0] or non-NULL (~[0, 0]). */
2742 if (POINTER_TYPE_P (type
) || POINTER_TYPE_P (TREE_TYPE (op0
)))
2747 if (range_is_nonnull (&vr0
)
2748 || (tree_unary_nonzero_warnv_p (code
, type
, op0
, &sop
)
2750 set_value_range_to_nonnull (vr
, type
);
2751 else if (range_is_null (&vr0
))
2752 set_value_range_to_null (vr
, type
);
2754 set_value_range_to_varying (vr
);
2759 /* Handle unary expressions on integer ranges. */
2760 if (CONVERT_EXPR_CODE_P (code
)
2761 && INTEGRAL_TYPE_P (type
)
2762 && INTEGRAL_TYPE_P (TREE_TYPE (op0
)))
2764 tree inner_type
= TREE_TYPE (op0
);
2765 tree outer_type
= type
;
2767 /* If VR0 is varying and we increase the type precision, assume
2768 a full range for the following transformation. */
2769 if (vr0
.type
== VR_VARYING
2770 && TYPE_PRECISION (inner_type
) < TYPE_PRECISION (outer_type
))
2772 vr0
.type
= VR_RANGE
;
2773 vr0
.min
= TYPE_MIN_VALUE (inner_type
);
2774 vr0
.max
= TYPE_MAX_VALUE (inner_type
);
2777 /* If VR0 is a constant range or anti-range and the conversion is
2778 not truncating we can convert the min and max values and
2779 canonicalize the resulting range. Otherwise we can do the
2780 conversion if the size of the range is less than what the
2781 precision of the target type can represent and the range is
2782 not an anti-range. */
2783 if ((vr0
.type
== VR_RANGE
2784 || vr0
.type
== VR_ANTI_RANGE
)
2785 && TREE_CODE (vr0
.min
) == INTEGER_CST
2786 && TREE_CODE (vr0
.max
) == INTEGER_CST
2787 && (!is_overflow_infinity (vr0
.min
)
2788 || (vr0
.type
== VR_RANGE
2789 && TYPE_PRECISION (outer_type
) > TYPE_PRECISION (inner_type
)
2790 && needs_overflow_infinity (outer_type
)
2791 && supports_overflow_infinity (outer_type
)))
2792 && (!is_overflow_infinity (vr0
.max
)
2793 || (vr0
.type
== VR_RANGE
2794 && TYPE_PRECISION (outer_type
) > TYPE_PRECISION (inner_type
)
2795 && needs_overflow_infinity (outer_type
)
2796 && supports_overflow_infinity (outer_type
)))
2797 && (TYPE_PRECISION (outer_type
) >= TYPE_PRECISION (inner_type
)
2798 || (vr0
.type
== VR_RANGE
2799 && integer_zerop (int_const_binop (RSHIFT_EXPR
,
2800 int_const_binop (MINUS_EXPR
, vr0
.max
, vr0
.min
, 0),
2801 size_int (TYPE_PRECISION (outer_type
)), 0)))))
2803 tree new_min
, new_max
;
2804 new_min
= force_fit_type_double (outer_type
,
2805 tree_to_double_int (vr0
.min
),
2807 new_max
= force_fit_type_double (outer_type
,
2808 tree_to_double_int (vr0
.max
),
2810 if (is_overflow_infinity (vr0
.min
))
2811 new_min
= negative_overflow_infinity (outer_type
);
2812 if (is_overflow_infinity (vr0
.max
))
2813 new_max
= positive_overflow_infinity (outer_type
);
2814 set_and_canonicalize_value_range (vr
, vr0
.type
,
2815 new_min
, new_max
, NULL
);
2819 set_value_range_to_varying (vr
);
2823 /* Conversion of a VR_VARYING value to a wider type can result
2824 in a usable range. So wait until after we've handled conversions
2825 before dropping the result to VR_VARYING if we had a source
2826 operand that is VR_VARYING. */
2827 if (vr0
.type
== VR_VARYING
)
2829 set_value_range_to_varying (vr
);
2833 /* Apply the operation to each end of the range and see what we end
2835 if (code
== NEGATE_EXPR
2836 && !TYPE_UNSIGNED (type
))
2838 /* NEGATE_EXPR flips the range around. We need to treat
2839 TYPE_MIN_VALUE specially. */
2840 if (is_positive_overflow_infinity (vr0
.max
))
2841 min
= negative_overflow_infinity (type
);
2842 else if (is_negative_overflow_infinity (vr0
.max
))
2843 min
= positive_overflow_infinity (type
);
2844 else if (!vrp_val_is_min (vr0
.max
))
2845 min
= fold_unary_to_constant (code
, type
, vr0
.max
);
2846 else if (needs_overflow_infinity (type
))
2848 if (supports_overflow_infinity (type
)
2849 && !is_overflow_infinity (vr0
.min
)
2850 && !vrp_val_is_min (vr0
.min
))
2851 min
= positive_overflow_infinity (type
);
2854 set_value_range_to_varying (vr
);
2859 min
= TYPE_MIN_VALUE (type
);
2861 if (is_positive_overflow_infinity (vr0
.min
))
2862 max
= negative_overflow_infinity (type
);
2863 else if (is_negative_overflow_infinity (vr0
.min
))
2864 max
= positive_overflow_infinity (type
);
2865 else if (!vrp_val_is_min (vr0
.min
))
2866 max
= fold_unary_to_constant (code
, type
, vr0
.min
);
2867 else if (needs_overflow_infinity (type
))
2869 if (supports_overflow_infinity (type
))
2870 max
= positive_overflow_infinity (type
);
2873 set_value_range_to_varying (vr
);
2878 max
= TYPE_MIN_VALUE (type
);
2880 else if (code
== NEGATE_EXPR
2881 && TYPE_UNSIGNED (type
))
2883 if (!range_includes_zero_p (&vr0
))
2885 max
= fold_unary_to_constant (code
, type
, vr0
.min
);
2886 min
= fold_unary_to_constant (code
, type
, vr0
.max
);
2890 if (range_is_null (&vr0
))
2891 set_value_range_to_null (vr
, type
);
2893 set_value_range_to_varying (vr
);
2897 else if (code
== ABS_EXPR
2898 && !TYPE_UNSIGNED (type
))
2900 /* -TYPE_MIN_VALUE = TYPE_MIN_VALUE with flag_wrapv so we can't get a
2902 if (!TYPE_OVERFLOW_UNDEFINED (type
)
2903 && ((vr0
.type
== VR_RANGE
2904 && vrp_val_is_min (vr0
.min
))
2905 || (vr0
.type
== VR_ANTI_RANGE
2906 && !vrp_val_is_min (vr0
.min
)
2907 && !range_includes_zero_p (&vr0
))))
2909 set_value_range_to_varying (vr
);
2913 /* ABS_EXPR may flip the range around, if the original range
2914 included negative values. */
2915 if (is_overflow_infinity (vr0
.min
))
2916 min
= positive_overflow_infinity (type
);
2917 else if (!vrp_val_is_min (vr0
.min
))
2918 min
= fold_unary_to_constant (code
, type
, vr0
.min
);
2919 else if (!needs_overflow_infinity (type
))
2920 min
= TYPE_MAX_VALUE (type
);
2921 else if (supports_overflow_infinity (type
))
2922 min
= positive_overflow_infinity (type
);
2925 set_value_range_to_varying (vr
);
2929 if (is_overflow_infinity (vr0
.max
))
2930 max
= positive_overflow_infinity (type
);
2931 else if (!vrp_val_is_min (vr0
.max
))
2932 max
= fold_unary_to_constant (code
, type
, vr0
.max
);
2933 else if (!needs_overflow_infinity (type
))
2934 max
= TYPE_MAX_VALUE (type
);
2935 else if (supports_overflow_infinity (type
)
2936 /* We shouldn't generate [+INF, +INF] as set_value_range
2937 doesn't like this and ICEs. */
2938 && !is_positive_overflow_infinity (min
))
2939 max
= positive_overflow_infinity (type
);
2942 set_value_range_to_varying (vr
);
2946 cmp
= compare_values (min
, max
);
2948 /* If a VR_ANTI_RANGEs contains zero, then we have
2949 ~[-INF, min(MIN, MAX)]. */
2950 if (vr0
.type
== VR_ANTI_RANGE
)
2952 if (range_includes_zero_p (&vr0
))
2954 /* Take the lower of the two values. */
2958 /* Create ~[-INF, min (abs(MIN), abs(MAX))]
2959 or ~[-INF + 1, min (abs(MIN), abs(MAX))] when
2960 flag_wrapv is set and the original anti-range doesn't include
2961 TYPE_MIN_VALUE, remember -TYPE_MIN_VALUE = TYPE_MIN_VALUE. */
2962 if (TYPE_OVERFLOW_WRAPS (type
))
2964 tree type_min_value
= TYPE_MIN_VALUE (type
);
2966 min
= (vr0
.min
!= type_min_value
2967 ? int_const_binop (PLUS_EXPR
, type_min_value
,
2968 integer_one_node
, 0)
2973 if (overflow_infinity_range_p (&vr0
))
2974 min
= negative_overflow_infinity (type
);
2976 min
= TYPE_MIN_VALUE (type
);
2981 /* All else has failed, so create the range [0, INF], even for
2982 flag_wrapv since TYPE_MIN_VALUE is in the original
2984 vr0
.type
= VR_RANGE
;
2985 min
= build_int_cst (type
, 0);
2986 if (needs_overflow_infinity (type
))
2988 if (supports_overflow_infinity (type
))
2989 max
= positive_overflow_infinity (type
);
2992 set_value_range_to_varying (vr
);
2997 max
= TYPE_MAX_VALUE (type
);
3001 /* If the range contains zero then we know that the minimum value in the
3002 range will be zero. */
3003 else if (range_includes_zero_p (&vr0
))
3007 min
= build_int_cst (type
, 0);
3011 /* If the range was reversed, swap MIN and MAX. */
3022 /* Otherwise, operate on each end of the range. */
3023 min
= fold_unary_to_constant (code
, type
, vr0
.min
);
3024 max
= fold_unary_to_constant (code
, type
, vr0
.max
);
3026 if (needs_overflow_infinity (type
))
3028 gcc_assert (code
!= NEGATE_EXPR
&& code
!= ABS_EXPR
);
3030 /* If both sides have overflowed, we don't know
3032 if ((is_overflow_infinity (vr0
.min
)
3033 || TREE_OVERFLOW (min
))
3034 && (is_overflow_infinity (vr0
.max
)
3035 || TREE_OVERFLOW (max
)))
3037 set_value_range_to_varying (vr
);
3041 if (is_overflow_infinity (vr0
.min
))
3043 else if (TREE_OVERFLOW (min
))
3045 if (supports_overflow_infinity (type
))
3046 min
= (tree_int_cst_sgn (min
) >= 0
3047 ? positive_overflow_infinity (TREE_TYPE (min
))
3048 : negative_overflow_infinity (TREE_TYPE (min
)));
3051 set_value_range_to_varying (vr
);
3056 if (is_overflow_infinity (vr0
.max
))
3058 else if (TREE_OVERFLOW (max
))
3060 if (supports_overflow_infinity (type
))
3061 max
= (tree_int_cst_sgn (max
) >= 0
3062 ? positive_overflow_infinity (TREE_TYPE (max
))
3063 : negative_overflow_infinity (TREE_TYPE (max
)));
3066 set_value_range_to_varying (vr
);
3073 cmp
= compare_values (min
, max
);
3074 if (cmp
== -2 || cmp
== 1)
3076 /* If the new range has its limits swapped around (MIN > MAX),
3077 then the operation caused one of them to wrap around, mark
3078 the new range VARYING. */
3079 set_value_range_to_varying (vr
);
3082 set_value_range (vr
, vr0
.type
, min
, max
, NULL
);
3086 /* Extract range information from a conditional expression EXPR based on
3087 the ranges of each of its operands and the expression code. */
3090 extract_range_from_cond_expr (value_range_t
*vr
, tree expr
)
3093 value_range_t vr0
= { VR_UNDEFINED
, NULL_TREE
, NULL_TREE
, NULL
};
3094 value_range_t vr1
= { VR_UNDEFINED
, NULL_TREE
, NULL_TREE
, NULL
};
3096 /* Get value ranges for each operand. For constant operands, create
3097 a new value range with the operand to simplify processing. */
3098 op0
= COND_EXPR_THEN (expr
);
3099 if (TREE_CODE (op0
) == SSA_NAME
)
3100 vr0
= *(get_value_range (op0
));
3101 else if (is_gimple_min_invariant (op0
))
3102 set_value_range_to_value (&vr0
, op0
, NULL
);
3104 set_value_range_to_varying (&vr0
);
3106 op1
= COND_EXPR_ELSE (expr
);
3107 if (TREE_CODE (op1
) == SSA_NAME
)
3108 vr1
= *(get_value_range (op1
));
3109 else if (is_gimple_min_invariant (op1
))
3110 set_value_range_to_value (&vr1
, op1
, NULL
);
3112 set_value_range_to_varying (&vr1
);
3114 /* The resulting value range is the union of the operand ranges */
3115 vrp_meet (&vr0
, &vr1
);
3116 copy_value_range (vr
, &vr0
);
3120 /* Extract range information from a comparison expression EXPR based
3121 on the range of its operand and the expression code. */
3124 extract_range_from_comparison (value_range_t
*vr
, enum tree_code code
,
3125 tree type
, tree op0
, tree op1
)
3130 val
= vrp_evaluate_conditional_warnv_with_ops (code
, op0
, op1
, false, &sop
,
3133 /* A disadvantage of using a special infinity as an overflow
3134 representation is that we lose the ability to record overflow
3135 when we don't have an infinity. So we have to ignore a result
3136 which relies on overflow. */
3138 if (val
&& !is_overflow_infinity (val
) && !sop
)
3140 /* Since this expression was found on the RHS of an assignment,
3141 its type may be different from _Bool. Convert VAL to EXPR's
3143 val
= fold_convert (type
, val
);
3144 if (is_gimple_min_invariant (val
))
3145 set_value_range_to_value (vr
, val
, vr
->equiv
);
3147 set_value_range (vr
, VR_RANGE
, val
, val
, vr
->equiv
);
3150 /* The result of a comparison is always true or false. */
3151 set_value_range_to_truthvalue (vr
, type
);
3154 /* Try to derive a nonnegative or nonzero range out of STMT relying
3155 primarily on generic routines in fold in conjunction with range data.
3156 Store the result in *VR */
3159 extract_range_basic (value_range_t
*vr
, gimple stmt
)
3162 tree type
= gimple_expr_type (stmt
);
3164 if (INTEGRAL_TYPE_P (type
)
3165 && gimple_stmt_nonnegative_warnv_p (stmt
, &sop
))
3166 set_value_range_to_nonnegative (vr
, type
,
3167 sop
|| stmt_overflow_infinity (stmt
));
3168 else if (vrp_stmt_computes_nonzero (stmt
, &sop
)
3170 set_value_range_to_nonnull (vr
, type
);
3172 set_value_range_to_varying (vr
);
3176 /* Try to compute a useful range out of assignment STMT and store it
3180 extract_range_from_assignment (value_range_t
*vr
, gimple stmt
)
3182 enum tree_code code
= gimple_assign_rhs_code (stmt
);
3184 if (code
== ASSERT_EXPR
)
3185 extract_range_from_assert (vr
, gimple_assign_rhs1 (stmt
));
3186 else if (code
== SSA_NAME
)
3187 extract_range_from_ssa_name (vr
, gimple_assign_rhs1 (stmt
));
3188 else if (TREE_CODE_CLASS (code
) == tcc_binary
3189 || code
== TRUTH_AND_EXPR
3190 || code
== TRUTH_OR_EXPR
3191 || code
== TRUTH_XOR_EXPR
)
3192 extract_range_from_binary_expr (vr
, gimple_assign_rhs_code (stmt
),
3193 gimple_expr_type (stmt
),
3194 gimple_assign_rhs1 (stmt
),
3195 gimple_assign_rhs2 (stmt
));
3196 else if (TREE_CODE_CLASS (code
) == tcc_unary
)
3197 extract_range_from_unary_expr (vr
, gimple_assign_rhs_code (stmt
),
3198 gimple_expr_type (stmt
),
3199 gimple_assign_rhs1 (stmt
));
3200 else if (code
== COND_EXPR
)
3201 extract_range_from_cond_expr (vr
, gimple_assign_rhs1 (stmt
));
3202 else if (TREE_CODE_CLASS (code
) == tcc_comparison
)
3203 extract_range_from_comparison (vr
, gimple_assign_rhs_code (stmt
),
3204 gimple_expr_type (stmt
),
3205 gimple_assign_rhs1 (stmt
),
3206 gimple_assign_rhs2 (stmt
));
3207 else if (get_gimple_rhs_class (code
) == GIMPLE_SINGLE_RHS
3208 && is_gimple_min_invariant (gimple_assign_rhs1 (stmt
)))
3209 set_value_range_to_value (vr
, gimple_assign_rhs1 (stmt
), NULL
);
3211 set_value_range_to_varying (vr
);
3213 if (vr
->type
== VR_VARYING
)
3214 extract_range_basic (vr
, stmt
);
3217 /* Given a range VR, a LOOP and a variable VAR, determine whether it
3218 would be profitable to adjust VR using scalar evolution information
3219 for VAR. If so, update VR with the new limits. */
3222 adjust_range_with_scev (value_range_t
*vr
, struct loop
*loop
,
3223 gimple stmt
, tree var
)
3225 tree init
, step
, chrec
, tmin
, tmax
, min
, max
, type
, tem
;
3226 enum ev_direction dir
;
3228 /* TODO. Don't adjust anti-ranges. An anti-range may provide
3229 better opportunities than a regular range, but I'm not sure. */
3230 if (vr
->type
== VR_ANTI_RANGE
)
3233 chrec
= instantiate_parameters (loop
, analyze_scalar_evolution (loop
, var
));
3235 /* Like in PR19590, scev can return a constant function. */
3236 if (is_gimple_min_invariant (chrec
))
3238 set_value_range_to_value (vr
, chrec
, vr
->equiv
);
3242 if (TREE_CODE (chrec
) != POLYNOMIAL_CHREC
)
3245 init
= initial_condition_in_loop_num (chrec
, loop
->num
);
3246 tem
= op_with_constant_singleton_value_range (init
);
3249 step
= evolution_part_in_loop_num (chrec
, loop
->num
);
3250 tem
= op_with_constant_singleton_value_range (step
);
3254 /* If STEP is symbolic, we can't know whether INIT will be the
3255 minimum or maximum value in the range. Also, unless INIT is
3256 a simple expression, compare_values and possibly other functions
3257 in tree-vrp won't be able to handle it. */
3258 if (step
== NULL_TREE
3259 || !is_gimple_min_invariant (step
)
3260 || !valid_value_p (init
))
3263 dir
= scev_direction (chrec
);
3264 if (/* Do not adjust ranges if we do not know whether the iv increases
3265 or decreases, ... */
3266 dir
== EV_DIR_UNKNOWN
3267 /* ... or if it may wrap. */
3268 || scev_probably_wraps_p (init
, step
, stmt
, get_chrec_loop (chrec
),
3272 /* We use TYPE_MIN_VALUE and TYPE_MAX_VALUE here instead of
3273 negative_overflow_infinity and positive_overflow_infinity,
3274 because we have concluded that the loop probably does not
3277 type
= TREE_TYPE (var
);
3278 if (POINTER_TYPE_P (type
) || !TYPE_MIN_VALUE (type
))
3279 tmin
= lower_bound_in_type (type
, type
);
3281 tmin
= TYPE_MIN_VALUE (type
);
3282 if (POINTER_TYPE_P (type
) || !TYPE_MAX_VALUE (type
))
3283 tmax
= upper_bound_in_type (type
, type
);
3285 tmax
= TYPE_MAX_VALUE (type
);
3287 if (vr
->type
== VR_VARYING
|| vr
->type
== VR_UNDEFINED
)
3292 /* For VARYING or UNDEFINED ranges, just about anything we get
3293 from scalar evolutions should be better. */
3295 if (dir
== EV_DIR_DECREASES
)
3300 /* If we would create an invalid range, then just assume we
3301 know absolutely nothing. This may be over-conservative,
3302 but it's clearly safe, and should happen only in unreachable
3303 parts of code, or for invalid programs. */
3304 if (compare_values (min
, max
) == 1)
3307 set_value_range (vr
, VR_RANGE
, min
, max
, vr
->equiv
);
3309 else if (vr
->type
== VR_RANGE
)
3314 if (dir
== EV_DIR_DECREASES
)
3316 /* INIT is the maximum value. If INIT is lower than VR->MAX
3317 but no smaller than VR->MIN, set VR->MAX to INIT. */
3318 if (compare_values (init
, max
) == -1)
3322 /* If we just created an invalid range with the minimum
3323 greater than the maximum, we fail conservatively.
3324 This should happen only in unreachable
3325 parts of code, or for invalid programs. */
3326 if (compare_values (min
, max
) == 1)
3330 /* According to the loop information, the variable does not
3331 overflow. If we think it does, probably because of an
3332 overflow due to arithmetic on a different INF value,
3334 if (is_negative_overflow_infinity (min
))
3339 /* If INIT is bigger than VR->MIN, set VR->MIN to INIT. */
3340 if (compare_values (init
, min
) == 1)
3344 /* Again, avoid creating invalid range by failing. */
3345 if (compare_values (min
, max
) == 1)
3349 if (is_positive_overflow_infinity (max
))
3353 set_value_range (vr
, VR_RANGE
, min
, max
, vr
->equiv
);
3357 /* Return true if VAR may overflow at STMT. This checks any available
3358 loop information to see if we can determine that VAR does not
3362 vrp_var_may_overflow (tree var
, gimple stmt
)
3365 tree chrec
, init
, step
;
3367 if (current_loops
== NULL
)
3370 l
= loop_containing_stmt (stmt
);
3375 chrec
= instantiate_parameters (l
, analyze_scalar_evolution (l
, var
));
3376 if (TREE_CODE (chrec
) != POLYNOMIAL_CHREC
)
3379 init
= initial_condition_in_loop_num (chrec
, l
->num
);
3380 step
= evolution_part_in_loop_num (chrec
, l
->num
);
3382 if (step
== NULL_TREE
3383 || !is_gimple_min_invariant (step
)
3384 || !valid_value_p (init
))
3387 /* If we get here, we know something useful about VAR based on the
3388 loop information. If it wraps, it may overflow. */
3390 if (scev_probably_wraps_p (init
, step
, stmt
, get_chrec_loop (chrec
),
3394 if (dump_file
&& (dump_flags
& TDF_DETAILS
) != 0)
3396 print_generic_expr (dump_file
, var
, 0);
3397 fprintf (dump_file
, ": loop information indicates does not overflow\n");
3404 /* Given two numeric value ranges VR0, VR1 and a comparison code COMP:
3406 - Return BOOLEAN_TRUE_NODE if VR0 COMP VR1 always returns true for
3407 all the values in the ranges.
3409 - Return BOOLEAN_FALSE_NODE if the comparison always returns false.
3411 - Return NULL_TREE if it is not always possible to determine the
3412 value of the comparison.
3414 Also set *STRICT_OVERFLOW_P to indicate whether a range with an
3415 overflow infinity was used in the test. */
3419 compare_ranges (enum tree_code comp
, value_range_t
*vr0
, value_range_t
*vr1
,
3420 bool *strict_overflow_p
)
3422 /* VARYING or UNDEFINED ranges cannot be compared. */
3423 if (vr0
->type
== VR_VARYING
3424 || vr0
->type
== VR_UNDEFINED
3425 || vr1
->type
== VR_VARYING
3426 || vr1
->type
== VR_UNDEFINED
)
3429 /* Anti-ranges need to be handled separately. */
3430 if (vr0
->type
== VR_ANTI_RANGE
|| vr1
->type
== VR_ANTI_RANGE
)
3432 /* If both are anti-ranges, then we cannot compute any
3434 if (vr0
->type
== VR_ANTI_RANGE
&& vr1
->type
== VR_ANTI_RANGE
)
3437 /* These comparisons are never statically computable. */
3444 /* Equality can be computed only between a range and an
3445 anti-range. ~[VAL1, VAL2] == [VAL1, VAL2] is always false. */
3446 if (vr0
->type
== VR_RANGE
)
3448 /* To simplify processing, make VR0 the anti-range. */
3449 value_range_t
*tmp
= vr0
;
3454 gcc_assert (comp
== NE_EXPR
|| comp
== EQ_EXPR
);
3456 if (compare_values_warnv (vr0
->min
, vr1
->min
, strict_overflow_p
) == 0
3457 && compare_values_warnv (vr0
->max
, vr1
->max
, strict_overflow_p
) == 0)
3458 return (comp
== NE_EXPR
) ? boolean_true_node
: boolean_false_node
;
3463 if (!usable_range_p (vr0
, strict_overflow_p
)
3464 || !usable_range_p (vr1
, strict_overflow_p
))
3467 /* Simplify processing. If COMP is GT_EXPR or GE_EXPR, switch the
3468 operands around and change the comparison code. */
3469 if (comp
== GT_EXPR
|| comp
== GE_EXPR
)
3472 comp
= (comp
== GT_EXPR
) ? LT_EXPR
: LE_EXPR
;
3478 if (comp
== EQ_EXPR
)
3480 /* Equality may only be computed if both ranges represent
3481 exactly one value. */
3482 if (compare_values_warnv (vr0
->min
, vr0
->max
, strict_overflow_p
) == 0
3483 && compare_values_warnv (vr1
->min
, vr1
->max
, strict_overflow_p
) == 0)
3485 int cmp_min
= compare_values_warnv (vr0
->min
, vr1
->min
,
3487 int cmp_max
= compare_values_warnv (vr0
->max
, vr1
->max
,
3489 if (cmp_min
== 0 && cmp_max
== 0)
3490 return boolean_true_node
;
3491 else if (cmp_min
!= -2 && cmp_max
!= -2)
3492 return boolean_false_node
;
3494 /* If [V0_MIN, V1_MAX] < [V1_MIN, V1_MAX] then V0 != V1. */
3495 else if (compare_values_warnv (vr0
->min
, vr1
->max
,
3496 strict_overflow_p
) == 1
3497 || compare_values_warnv (vr1
->min
, vr0
->max
,
3498 strict_overflow_p
) == 1)
3499 return boolean_false_node
;
3503 else if (comp
== NE_EXPR
)
3507 /* If VR0 is completely to the left or completely to the right
3508 of VR1, they are always different. Notice that we need to
3509 make sure that both comparisons yield similar results to
3510 avoid comparing values that cannot be compared at
3512 cmp1
= compare_values_warnv (vr0
->max
, vr1
->min
, strict_overflow_p
);
3513 cmp2
= compare_values_warnv (vr0
->min
, vr1
->max
, strict_overflow_p
);
3514 if ((cmp1
== -1 && cmp2
== -1) || (cmp1
== 1 && cmp2
== 1))
3515 return boolean_true_node
;
3517 /* If VR0 and VR1 represent a single value and are identical,
3519 else if (compare_values_warnv (vr0
->min
, vr0
->max
,
3520 strict_overflow_p
) == 0
3521 && compare_values_warnv (vr1
->min
, vr1
->max
,
3522 strict_overflow_p
) == 0
3523 && compare_values_warnv (vr0
->min
, vr1
->min
,
3524 strict_overflow_p
) == 0
3525 && compare_values_warnv (vr0
->max
, vr1
->max
,
3526 strict_overflow_p
) == 0)
3527 return boolean_false_node
;
3529 /* Otherwise, they may or may not be different. */
3533 else if (comp
== LT_EXPR
|| comp
== LE_EXPR
)
3537 /* If VR0 is to the left of VR1, return true. */
3538 tst
= compare_values_warnv (vr0
->max
, vr1
->min
, strict_overflow_p
);
3539 if ((comp
== LT_EXPR
&& tst
== -1)
3540 || (comp
== LE_EXPR
&& (tst
== -1 || tst
== 0)))
3542 if (overflow_infinity_range_p (vr0
)
3543 || overflow_infinity_range_p (vr1
))
3544 *strict_overflow_p
= true;
3545 return boolean_true_node
;
3548 /* If VR0 is to the right of VR1, return false. */
3549 tst
= compare_values_warnv (vr0
->min
, vr1
->max
, strict_overflow_p
);
3550 if ((comp
== LT_EXPR
&& (tst
== 0 || tst
== 1))
3551 || (comp
== LE_EXPR
&& tst
== 1))
3553 if (overflow_infinity_range_p (vr0
)
3554 || overflow_infinity_range_p (vr1
))
3555 *strict_overflow_p
= true;
3556 return boolean_false_node
;
3559 /* Otherwise, we don't know. */
3567 /* Given a value range VR, a value VAL and a comparison code COMP, return
3568 BOOLEAN_TRUE_NODE if VR COMP VAL always returns true for all the
3569 values in VR. Return BOOLEAN_FALSE_NODE if the comparison
3570 always returns false. Return NULL_TREE if it is not always
3571 possible to determine the value of the comparison. Also set
3572 *STRICT_OVERFLOW_P to indicate whether a range with an overflow
3573 infinity was used in the test. */
3576 compare_range_with_value (enum tree_code comp
, value_range_t
*vr
, tree val
,
3577 bool *strict_overflow_p
)
3579 if (vr
->type
== VR_VARYING
|| vr
->type
== VR_UNDEFINED
)
3582 /* Anti-ranges need to be handled separately. */
3583 if (vr
->type
== VR_ANTI_RANGE
)
3585 /* For anti-ranges, the only predicates that we can compute at
3586 compile time are equality and inequality. */
3593 /* ~[VAL_1, VAL_2] OP VAL is known if VAL_1 <= VAL <= VAL_2. */
3594 if (value_inside_range (val
, vr
) == 1)
3595 return (comp
== NE_EXPR
) ? boolean_true_node
: boolean_false_node
;
3600 if (!usable_range_p (vr
, strict_overflow_p
))
3603 if (comp
== EQ_EXPR
)
3605 /* EQ_EXPR may only be computed if VR represents exactly
3607 if (compare_values_warnv (vr
->min
, vr
->max
, strict_overflow_p
) == 0)
3609 int cmp
= compare_values_warnv (vr
->min
, val
, strict_overflow_p
);
3611 return boolean_true_node
;
3612 else if (cmp
== -1 || cmp
== 1 || cmp
== 2)
3613 return boolean_false_node
;
3615 else if (compare_values_warnv (val
, vr
->min
, strict_overflow_p
) == -1
3616 || compare_values_warnv (vr
->max
, val
, strict_overflow_p
) == -1)
3617 return boolean_false_node
;
3621 else if (comp
== NE_EXPR
)
3623 /* If VAL is not inside VR, then they are always different. */
3624 if (compare_values_warnv (vr
->max
, val
, strict_overflow_p
) == -1
3625 || compare_values_warnv (vr
->min
, val
, strict_overflow_p
) == 1)
3626 return boolean_true_node
;
3628 /* If VR represents exactly one value equal to VAL, then return
3630 if (compare_values_warnv (vr
->min
, vr
->max
, strict_overflow_p
) == 0
3631 && compare_values_warnv (vr
->min
, val
, strict_overflow_p
) == 0)
3632 return boolean_false_node
;
3634 /* Otherwise, they may or may not be different. */
3637 else if (comp
== LT_EXPR
|| comp
== LE_EXPR
)
3641 /* If VR is to the left of VAL, return true. */
3642 tst
= compare_values_warnv (vr
->max
, val
, strict_overflow_p
);
3643 if ((comp
== LT_EXPR
&& tst
== -1)
3644 || (comp
== LE_EXPR
&& (tst
== -1 || tst
== 0)))
3646 if (overflow_infinity_range_p (vr
))
3647 *strict_overflow_p
= true;
3648 return boolean_true_node
;
3651 /* If VR is to the right of VAL, return false. */
3652 tst
= compare_values_warnv (vr
->min
, val
, strict_overflow_p
);
3653 if ((comp
== LT_EXPR
&& (tst
== 0 || tst
== 1))
3654 || (comp
== LE_EXPR
&& tst
== 1))
3656 if (overflow_infinity_range_p (vr
))
3657 *strict_overflow_p
= true;
3658 return boolean_false_node
;
3661 /* Otherwise, we don't know. */
3664 else if (comp
== GT_EXPR
|| comp
== GE_EXPR
)
3668 /* If VR is to the right of VAL, return true. */
3669 tst
= compare_values_warnv (vr
->min
, val
, strict_overflow_p
);
3670 if ((comp
== GT_EXPR
&& tst
== 1)
3671 || (comp
== GE_EXPR
&& (tst
== 0 || tst
== 1)))
3673 if (overflow_infinity_range_p (vr
))
3674 *strict_overflow_p
= true;
3675 return boolean_true_node
;
3678 /* If VR is to the left of VAL, return false. */
3679 tst
= compare_values_warnv (vr
->max
, val
, strict_overflow_p
);
3680 if ((comp
== GT_EXPR
&& (tst
== -1 || tst
== 0))
3681 || (comp
== GE_EXPR
&& tst
== -1))
3683 if (overflow_infinity_range_p (vr
))
3684 *strict_overflow_p
= true;
3685 return boolean_false_node
;
3688 /* Otherwise, we don't know. */
3696 /* Debugging dumps. */
3698 void dump_value_range (FILE *, value_range_t
*);
3699 void debug_value_range (value_range_t
*);
3700 void dump_all_value_ranges (FILE *);
3701 void debug_all_value_ranges (void);
3702 void dump_vr_equiv (FILE *, bitmap
);
3703 void debug_vr_equiv (bitmap
);
3706 /* Dump value range VR to FILE. */
3709 dump_value_range (FILE *file
, value_range_t
*vr
)
3712 fprintf (file
, "[]");
3713 else if (vr
->type
== VR_UNDEFINED
)
3714 fprintf (file
, "UNDEFINED");
3715 else if (vr
->type
== VR_RANGE
|| vr
->type
== VR_ANTI_RANGE
)
3717 tree type
= TREE_TYPE (vr
->min
);
3719 fprintf (file
, "%s[", (vr
->type
== VR_ANTI_RANGE
) ? "~" : "");
3721 if (is_negative_overflow_infinity (vr
->min
))
3722 fprintf (file
, "-INF(OVF)");
3723 else if (INTEGRAL_TYPE_P (type
)
3724 && !TYPE_UNSIGNED (type
)
3725 && vrp_val_is_min (vr
->min
))
3726 fprintf (file
, "-INF");
3728 print_generic_expr (file
, vr
->min
, 0);
3730 fprintf (file
, ", ");
3732 if (is_positive_overflow_infinity (vr
->max
))
3733 fprintf (file
, "+INF(OVF)");
3734 else if (INTEGRAL_TYPE_P (type
)
3735 && vrp_val_is_max (vr
->max
))
3736 fprintf (file
, "+INF");
3738 print_generic_expr (file
, vr
->max
, 0);
3740 fprintf (file
, "]");
3747 fprintf (file
, " EQUIVALENCES: { ");
3749 EXECUTE_IF_SET_IN_BITMAP (vr
->equiv
, 0, i
, bi
)
3751 print_generic_expr (file
, ssa_name (i
), 0);
3752 fprintf (file
, " ");
3756 fprintf (file
, "} (%u elements)", c
);
3759 else if (vr
->type
== VR_VARYING
)
3760 fprintf (file
, "VARYING");
3762 fprintf (file
, "INVALID RANGE");
3766 /* Dump value range VR to stderr. */
3769 debug_value_range (value_range_t
*vr
)
3771 dump_value_range (stderr
, vr
);
3772 fprintf (stderr
, "\n");
3776 /* Dump value ranges of all SSA_NAMEs to FILE. */
3779 dump_all_value_ranges (FILE *file
)
3783 for (i
= 0; i
< num_ssa_names
; i
++)
3787 print_generic_expr (file
, ssa_name (i
), 0);
3788 fprintf (file
, ": ");
3789 dump_value_range (file
, vr_value
[i
]);
3790 fprintf (file
, "\n");
3794 fprintf (file
, "\n");
3798 /* Dump all value ranges to stderr. */
3801 debug_all_value_ranges (void)
3803 dump_all_value_ranges (stderr
);
3807 /* Given a COND_EXPR COND of the form 'V OP W', and an SSA name V,
3808 create a new SSA name N and return the assertion assignment
3809 'V = ASSERT_EXPR <V, V OP W>'. */
3812 build_assert_expr_for (tree cond
, tree v
)
3817 gcc_assert (TREE_CODE (v
) == SSA_NAME
);
3818 n
= duplicate_ssa_name (v
, NULL
);
3820 if (COMPARISON_CLASS_P (cond
))
3822 tree a
= build2 (ASSERT_EXPR
, TREE_TYPE (v
), v
, cond
);
3823 assertion
= gimple_build_assign (n
, a
);
3825 else if (TREE_CODE (cond
) == TRUTH_NOT_EXPR
)
3827 /* Given !V, build the assignment N = false. */
3828 tree op0
= TREE_OPERAND (cond
, 0);
3829 gcc_assert (op0
== v
);
3830 assertion
= gimple_build_assign (n
, boolean_false_node
);
3832 else if (TREE_CODE (cond
) == SSA_NAME
)
3834 /* Given V, build the assignment N = true. */
3835 gcc_assert (v
== cond
);
3836 assertion
= gimple_build_assign (n
, boolean_true_node
);
3841 SSA_NAME_DEF_STMT (n
) = assertion
;
3843 /* The new ASSERT_EXPR, creates a new SSA name that replaces the
3844 operand of the ASSERT_EXPR. Register the new name and the old one
3845 in the replacement table so that we can fix the SSA web after
3846 adding all the ASSERT_EXPRs. */
3847 register_new_name_mapping (n
, v
);
3853 /* Return false if EXPR is a predicate expression involving floating
3857 fp_predicate (gimple stmt
)
3859 GIMPLE_CHECK (stmt
, GIMPLE_COND
);
3861 return FLOAT_TYPE_P (TREE_TYPE (gimple_cond_lhs (stmt
)));
3865 /* If the range of values taken by OP can be inferred after STMT executes,
3866 return the comparison code (COMP_CODE_P) and value (VAL_P) that
3867 describes the inferred range. Return true if a range could be
3871 infer_value_range (gimple stmt
, tree op
, enum tree_code
*comp_code_p
, tree
*val_p
)
3874 *comp_code_p
= ERROR_MARK
;
3876 /* Do not attempt to infer anything in names that flow through
3878 if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (op
))
3881 /* Similarly, don't infer anything from statements that may throw
3883 if (stmt_could_throw_p (stmt
))
3886 /* If STMT is the last statement of a basic block with no
3887 successors, there is no point inferring anything about any of its
3888 operands. We would not be able to find a proper insertion point
3889 for the assertion, anyway. */
3890 if (stmt_ends_bb_p (stmt
) && EDGE_COUNT (gimple_bb (stmt
)->succs
) == 0)
3893 /* We can only assume that a pointer dereference will yield
3894 non-NULL if -fdelete-null-pointer-checks is enabled. */
3895 if (flag_delete_null_pointer_checks
3896 && POINTER_TYPE_P (TREE_TYPE (op
))
3897 && gimple_code (stmt
) != GIMPLE_ASM
)
3899 unsigned num_uses
, num_loads
, num_stores
;
3901 count_uses_and_derefs (op
, stmt
, &num_uses
, &num_loads
, &num_stores
);
3902 if (num_loads
+ num_stores
> 0)
3904 *val_p
= build_int_cst (TREE_TYPE (op
), 0);
3905 *comp_code_p
= NE_EXPR
;
3914 void dump_asserts_for (FILE *, tree
);
3915 void debug_asserts_for (tree
);
3916 void dump_all_asserts (FILE *);
3917 void debug_all_asserts (void);
3919 /* Dump all the registered assertions for NAME to FILE. */
3922 dump_asserts_for (FILE *file
, tree name
)
3926 fprintf (file
, "Assertions to be inserted for ");
3927 print_generic_expr (file
, name
, 0);
3928 fprintf (file
, "\n");
3930 loc
= asserts_for
[SSA_NAME_VERSION (name
)];
3933 fprintf (file
, "\t");
3934 print_gimple_stmt (file
, gsi_stmt (loc
->si
), 0, 0);
3935 fprintf (file
, "\n\tBB #%d", loc
->bb
->index
);
3938 fprintf (file
, "\n\tEDGE %d->%d", loc
->e
->src
->index
,
3939 loc
->e
->dest
->index
);
3940 dump_edge_info (file
, loc
->e
, 0);
3942 fprintf (file
, "\n\tPREDICATE: ");
3943 print_generic_expr (file
, name
, 0);
3944 fprintf (file
, " %s ", tree_code_name
[(int)loc
->comp_code
]);
3945 print_generic_expr (file
, loc
->val
, 0);
3946 fprintf (file
, "\n\n");
3950 fprintf (file
, "\n");
3954 /* Dump all the registered assertions for NAME to stderr. */
3957 debug_asserts_for (tree name
)
3959 dump_asserts_for (stderr
, name
);
3963 /* Dump all the registered assertions for all the names to FILE. */
3966 dump_all_asserts (FILE *file
)
3971 fprintf (file
, "\nASSERT_EXPRs to be inserted\n\n");
3972 EXECUTE_IF_SET_IN_BITMAP (need_assert_for
, 0, i
, bi
)
3973 dump_asserts_for (file
, ssa_name (i
));
3974 fprintf (file
, "\n");
3978 /* Dump all the registered assertions for all the names to stderr. */
3981 debug_all_asserts (void)
3983 dump_all_asserts (stderr
);
3987 /* If NAME doesn't have an ASSERT_EXPR registered for asserting
3988 'EXPR COMP_CODE VAL' at a location that dominates block BB or
3989 E->DEST, then register this location as a possible insertion point
3990 for ASSERT_EXPR <NAME, EXPR COMP_CODE VAL>.
3992 BB, E and SI provide the exact insertion point for the new
3993 ASSERT_EXPR. If BB is NULL, then the ASSERT_EXPR is to be inserted
3994 on edge E. Otherwise, if E is NULL, the ASSERT_EXPR is inserted on
3995 BB. If SI points to a COND_EXPR or a SWITCH_EXPR statement, then E
3996 must not be NULL. */
3999 register_new_assert_for (tree name
, tree expr
,
4000 enum tree_code comp_code
,
4004 gimple_stmt_iterator si
)
4006 assert_locus_t n
, loc
, last_loc
;
4007 basic_block dest_bb
;
4009 #if defined ENABLE_CHECKING
4010 gcc_assert (bb
== NULL
|| e
== NULL
);
4013 gcc_assert (gimple_code (gsi_stmt (si
)) != GIMPLE_COND
4014 && gimple_code (gsi_stmt (si
)) != GIMPLE_SWITCH
);
4017 /* Never build an assert comparing against an integer constant with
4018 TREE_OVERFLOW set. This confuses our undefined overflow warning
4020 if (TREE_CODE (val
) == INTEGER_CST
4021 && TREE_OVERFLOW (val
))
4022 val
= build_int_cst_wide (TREE_TYPE (val
),
4023 TREE_INT_CST_LOW (val
), TREE_INT_CST_HIGH (val
));
4025 /* The new assertion A will be inserted at BB or E. We need to
4026 determine if the new location is dominated by a previously
4027 registered location for A. If we are doing an edge insertion,
4028 assume that A will be inserted at E->DEST. Note that this is not
4031 If E is a critical edge, it will be split. But even if E is
4032 split, the new block will dominate the same set of blocks that
4035 The reverse, however, is not true, blocks dominated by E->DEST
4036 will not be dominated by the new block created to split E. So,
4037 if the insertion location is on a critical edge, we will not use
4038 the new location to move another assertion previously registered
4039 at a block dominated by E->DEST. */
4040 dest_bb
= (bb
) ? bb
: e
->dest
;
4042 /* If NAME already has an ASSERT_EXPR registered for COMP_CODE and
4043 VAL at a block dominating DEST_BB, then we don't need to insert a new
4044 one. Similarly, if the same assertion already exists at a block
4045 dominated by DEST_BB and the new location is not on a critical
4046 edge, then update the existing location for the assertion (i.e.,
4047 move the assertion up in the dominance tree).
4049 Note, this is implemented as a simple linked list because there
4050 should not be more than a handful of assertions registered per
4051 name. If this becomes a performance problem, a table hashed by
4052 COMP_CODE and VAL could be implemented. */
4053 loc
= asserts_for
[SSA_NAME_VERSION (name
)];
4057 if (loc
->comp_code
== comp_code
4059 || operand_equal_p (loc
->val
, val
, 0))
4060 && (loc
->expr
== expr
4061 || operand_equal_p (loc
->expr
, expr
, 0)))
4063 /* If the assertion NAME COMP_CODE VAL has already been
4064 registered at a basic block that dominates DEST_BB, then
4065 we don't need to insert the same assertion again. Note
4066 that we don't check strict dominance here to avoid
4067 replicating the same assertion inside the same basic
4068 block more than once (e.g., when a pointer is
4069 dereferenced several times inside a block).
4071 An exception to this rule are edge insertions. If the
4072 new assertion is to be inserted on edge E, then it will
4073 dominate all the other insertions that we may want to
4074 insert in DEST_BB. So, if we are doing an edge
4075 insertion, don't do this dominance check. */
4077 && dominated_by_p (CDI_DOMINATORS
, dest_bb
, loc
->bb
))
4080 /* Otherwise, if E is not a critical edge and DEST_BB
4081 dominates the existing location for the assertion, move
4082 the assertion up in the dominance tree by updating its
4083 location information. */
4084 if ((e
== NULL
|| !EDGE_CRITICAL_P (e
))
4085 && dominated_by_p (CDI_DOMINATORS
, loc
->bb
, dest_bb
))
4094 /* Update the last node of the list and move to the next one. */
4099 /* If we didn't find an assertion already registered for
4100 NAME COMP_CODE VAL, add a new one at the end of the list of
4101 assertions associated with NAME. */
4102 n
= XNEW (struct assert_locus_d
);
4106 n
->comp_code
= comp_code
;
4114 asserts_for
[SSA_NAME_VERSION (name
)] = n
;
4116 bitmap_set_bit (need_assert_for
, SSA_NAME_VERSION (name
));
4119 /* (COND_OP0 COND_CODE COND_OP1) is a predicate which uses NAME.
4120 Extract a suitable test code and value and store them into *CODE_P and
4121 *VAL_P so the predicate is normalized to NAME *CODE_P *VAL_P.
4123 If no extraction was possible, return FALSE, otherwise return TRUE.
4125 If INVERT is true, then we invert the result stored into *CODE_P. */
4128 extract_code_and_val_from_cond_with_ops (tree name
, enum tree_code cond_code
,
4129 tree cond_op0
, tree cond_op1
,
4130 bool invert
, enum tree_code
*code_p
,
4133 enum tree_code comp_code
;
4136 /* Otherwise, we have a comparison of the form NAME COMP VAL
4137 or VAL COMP NAME. */
4138 if (name
== cond_op1
)
4140 /* If the predicate is of the form VAL COMP NAME, flip
4141 COMP around because we need to register NAME as the
4142 first operand in the predicate. */
4143 comp_code
= swap_tree_comparison (cond_code
);
4148 /* The comparison is of the form NAME COMP VAL, so the
4149 comparison code remains unchanged. */
4150 comp_code
= cond_code
;
4154 /* Invert the comparison code as necessary. */
4156 comp_code
= invert_tree_comparison (comp_code
, 0);
4158 /* VRP does not handle float types. */
4159 if (SCALAR_FLOAT_TYPE_P (TREE_TYPE (val
)))
4162 /* Do not register always-false predicates.
4163 FIXME: this works around a limitation in fold() when dealing with
4164 enumerations. Given 'enum { N1, N2 } x;', fold will not
4165 fold 'if (x > N2)' to 'if (0)'. */
4166 if ((comp_code
== GT_EXPR
|| comp_code
== LT_EXPR
)
4167 && INTEGRAL_TYPE_P (TREE_TYPE (val
)))
4169 tree min
= TYPE_MIN_VALUE (TREE_TYPE (val
));
4170 tree max
= TYPE_MAX_VALUE (TREE_TYPE (val
));
4172 if (comp_code
== GT_EXPR
4174 || compare_values (val
, max
) == 0))
4177 if (comp_code
== LT_EXPR
4179 || compare_values (val
, min
) == 0))
4182 *code_p
= comp_code
;
4187 /* Try to register an edge assertion for SSA name NAME on edge E for
4188 the condition COND contributing to the conditional jump pointed to by BSI.
4189 Invert the condition COND if INVERT is true.
4190 Return true if an assertion for NAME could be registered. */
4193 register_edge_assert_for_2 (tree name
, edge e
, gimple_stmt_iterator bsi
,
4194 enum tree_code cond_code
,
4195 tree cond_op0
, tree cond_op1
, bool invert
)
4198 enum tree_code comp_code
;
4199 bool retval
= false;
4201 if (!extract_code_and_val_from_cond_with_ops (name
, cond_code
,
4204 invert
, &comp_code
, &val
))
4207 /* Only register an ASSERT_EXPR if NAME was found in the sub-graph
4208 reachable from E. */
4209 if (live_on_edge (e
, name
)
4210 && !has_single_use (name
))
4212 register_new_assert_for (name
, name
, comp_code
, val
, NULL
, e
, bsi
);
4216 /* In the case of NAME <= CST and NAME being defined as
4217 NAME = (unsigned) NAME2 + CST2 we can assert NAME2 >= -CST2
4218 and NAME2 <= CST - CST2. We can do the same for NAME > CST.
4219 This catches range and anti-range tests. */
4220 if ((comp_code
== LE_EXPR
4221 || comp_code
== GT_EXPR
)
4222 && TREE_CODE (val
) == INTEGER_CST
4223 && TYPE_UNSIGNED (TREE_TYPE (val
)))
4225 gimple def_stmt
= SSA_NAME_DEF_STMT (name
);
4226 tree cst2
= NULL_TREE
, name2
= NULL_TREE
, name3
= NULL_TREE
;
4228 /* Extract CST2 from the (optional) addition. */
4229 if (is_gimple_assign (def_stmt
)
4230 && gimple_assign_rhs_code (def_stmt
) == PLUS_EXPR
)
4232 name2
= gimple_assign_rhs1 (def_stmt
);
4233 cst2
= gimple_assign_rhs2 (def_stmt
);
4234 if (TREE_CODE (name2
) == SSA_NAME
4235 && TREE_CODE (cst2
) == INTEGER_CST
)
4236 def_stmt
= SSA_NAME_DEF_STMT (name2
);
4239 /* Extract NAME2 from the (optional) sign-changing cast. */
4240 if (gimple_assign_cast_p (def_stmt
))
4242 if (CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (def_stmt
))
4243 && ! TYPE_UNSIGNED (TREE_TYPE (gimple_assign_rhs1 (def_stmt
)))
4244 && (TYPE_PRECISION (gimple_expr_type (def_stmt
))
4245 == TYPE_PRECISION (TREE_TYPE (gimple_assign_rhs1 (def_stmt
)))))
4246 name3
= gimple_assign_rhs1 (def_stmt
);
4249 /* If name3 is used later, create an ASSERT_EXPR for it. */
4250 if (name3
!= NULL_TREE
4251 && TREE_CODE (name3
) == SSA_NAME
4252 && (cst2
== NULL_TREE
4253 || TREE_CODE (cst2
) == INTEGER_CST
)
4254 && INTEGRAL_TYPE_P (TREE_TYPE (name3
))
4255 && live_on_edge (e
, name3
)
4256 && !has_single_use (name3
))
4260 /* Build an expression for the range test. */
4261 tmp
= build1 (NOP_EXPR
, TREE_TYPE (name
), name3
);
4262 if (cst2
!= NULL_TREE
)
4263 tmp
= build2 (PLUS_EXPR
, TREE_TYPE (name
), tmp
, cst2
);
4267 fprintf (dump_file
, "Adding assert for ");
4268 print_generic_expr (dump_file
, name3
, 0);
4269 fprintf (dump_file
, " from ");
4270 print_generic_expr (dump_file
, tmp
, 0);
4271 fprintf (dump_file
, "\n");
4274 register_new_assert_for (name3
, tmp
, comp_code
, val
, NULL
, e
, bsi
);
4279 /* If name2 is used later, create an ASSERT_EXPR for it. */
4280 if (name2
!= NULL_TREE
4281 && TREE_CODE (name2
) == SSA_NAME
4282 && TREE_CODE (cst2
) == INTEGER_CST
4283 && INTEGRAL_TYPE_P (TREE_TYPE (name2
))
4284 && live_on_edge (e
, name2
)
4285 && !has_single_use (name2
))
4289 /* Build an expression for the range test. */
4291 if (TREE_TYPE (name
) != TREE_TYPE (name2
))
4292 tmp
= build1 (NOP_EXPR
, TREE_TYPE (name
), tmp
);
4293 if (cst2
!= NULL_TREE
)
4294 tmp
= build2 (PLUS_EXPR
, TREE_TYPE (name
), tmp
, cst2
);
4298 fprintf (dump_file
, "Adding assert for ");
4299 print_generic_expr (dump_file
, name2
, 0);
4300 fprintf (dump_file
, " from ");
4301 print_generic_expr (dump_file
, tmp
, 0);
4302 fprintf (dump_file
, "\n");
4305 register_new_assert_for (name2
, tmp
, comp_code
, val
, NULL
, e
, bsi
);
4314 /* OP is an operand of a truth value expression which is known to have
4315 a particular value. Register any asserts for OP and for any
4316 operands in OP's defining statement.
4318 If CODE is EQ_EXPR, then we want to register OP is zero (false),
4319 if CODE is NE_EXPR, then we want to register OP is nonzero (true). */
4322 register_edge_assert_for_1 (tree op
, enum tree_code code
,
4323 edge e
, gimple_stmt_iterator bsi
)
4325 bool retval
= false;
4328 enum tree_code rhs_code
;
4330 /* We only care about SSA_NAMEs. */
4331 if (TREE_CODE (op
) != SSA_NAME
)
4334 /* We know that OP will have a zero or nonzero value. If OP is used
4335 more than once go ahead and register an assert for OP.
4337 The FOUND_IN_SUBGRAPH support is not helpful in this situation as
4338 it will always be set for OP (because OP is used in a COND_EXPR in
4340 if (!has_single_use (op
))
4342 val
= build_int_cst (TREE_TYPE (op
), 0);
4343 register_new_assert_for (op
, op
, code
, val
, NULL
, e
, bsi
);
4347 /* Now look at how OP is set. If it's set from a comparison,
4348 a truth operation or some bit operations, then we may be able
4349 to register information about the operands of that assignment. */
4350 op_def
= SSA_NAME_DEF_STMT (op
);
4351 if (gimple_code (op_def
) != GIMPLE_ASSIGN
)
4354 rhs_code
= gimple_assign_rhs_code (op_def
);
4356 if (TREE_CODE_CLASS (rhs_code
) == tcc_comparison
)
4358 bool invert
= (code
== EQ_EXPR
? true : false);
4359 tree op0
= gimple_assign_rhs1 (op_def
);
4360 tree op1
= gimple_assign_rhs2 (op_def
);
4362 if (TREE_CODE (op0
) == SSA_NAME
)
4363 retval
|= register_edge_assert_for_2 (op0
, e
, bsi
, rhs_code
, op0
, op1
,
4365 if (TREE_CODE (op1
) == SSA_NAME
)
4366 retval
|= register_edge_assert_for_2 (op1
, e
, bsi
, rhs_code
, op0
, op1
,
4369 else if ((code
== NE_EXPR
4370 && (gimple_assign_rhs_code (op_def
) == TRUTH_AND_EXPR
4371 || gimple_assign_rhs_code (op_def
) == BIT_AND_EXPR
))
4373 && (gimple_assign_rhs_code (op_def
) == TRUTH_OR_EXPR
4374 || gimple_assign_rhs_code (op_def
) == BIT_IOR_EXPR
)))
4376 /* Recurse on each operand. */
4377 retval
|= register_edge_assert_for_1 (gimple_assign_rhs1 (op_def
),
4379 retval
|= register_edge_assert_for_1 (gimple_assign_rhs2 (op_def
),
4382 else if (gimple_assign_rhs_code (op_def
) == TRUTH_NOT_EXPR
)
4384 /* Recurse, flipping CODE. */
4385 code
= invert_tree_comparison (code
, false);
4386 retval
|= register_edge_assert_for_1 (gimple_assign_rhs1 (op_def
),
4389 else if (gimple_assign_rhs_code (op_def
) == SSA_NAME
)
4391 /* Recurse through the copy. */
4392 retval
|= register_edge_assert_for_1 (gimple_assign_rhs1 (op_def
),
4395 else if (CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (op_def
)))
4397 /* Recurse through the type conversion. */
4398 retval
|= register_edge_assert_for_1 (gimple_assign_rhs1 (op_def
),
4405 /* Try to register an edge assertion for SSA name NAME on edge E for
4406 the condition COND contributing to the conditional jump pointed to by SI.
4407 Return true if an assertion for NAME could be registered. */
4410 register_edge_assert_for (tree name
, edge e
, gimple_stmt_iterator si
,
4411 enum tree_code cond_code
, tree cond_op0
,
4415 enum tree_code comp_code
;
4416 bool retval
= false;
4417 bool is_else_edge
= (e
->flags
& EDGE_FALSE_VALUE
) != 0;
4419 /* Do not attempt to infer anything in names that flow through
4421 if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (name
))
4424 if (!extract_code_and_val_from_cond_with_ops (name
, cond_code
,
4430 /* Register ASSERT_EXPRs for name. */
4431 retval
|= register_edge_assert_for_2 (name
, e
, si
, cond_code
, cond_op0
,
4432 cond_op1
, is_else_edge
);
4435 /* If COND is effectively an equality test of an SSA_NAME against
4436 the value zero or one, then we may be able to assert values
4437 for SSA_NAMEs which flow into COND. */
4439 /* In the case of NAME == 1 or NAME != 0, for TRUTH_AND_EXPR defining
4440 statement of NAME we can assert both operands of the TRUTH_AND_EXPR
4441 have nonzero value. */
4442 if (((comp_code
== EQ_EXPR
&& integer_onep (val
))
4443 || (comp_code
== NE_EXPR
&& integer_zerop (val
))))
4445 gimple def_stmt
= SSA_NAME_DEF_STMT (name
);
4447 if (is_gimple_assign (def_stmt
)
4448 && (gimple_assign_rhs_code (def_stmt
) == TRUTH_AND_EXPR
4449 || gimple_assign_rhs_code (def_stmt
) == BIT_AND_EXPR
))
4451 tree op0
= gimple_assign_rhs1 (def_stmt
);
4452 tree op1
= gimple_assign_rhs2 (def_stmt
);
4453 retval
|= register_edge_assert_for_1 (op0
, NE_EXPR
, e
, si
);
4454 retval
|= register_edge_assert_for_1 (op1
, NE_EXPR
, e
, si
);
4458 /* In the case of NAME == 0 or NAME != 1, for TRUTH_OR_EXPR defining
4459 statement of NAME we can assert both operands of the TRUTH_OR_EXPR
4461 if (((comp_code
== EQ_EXPR
&& integer_zerop (val
))
4462 || (comp_code
== NE_EXPR
&& integer_onep (val
))))
4464 gimple def_stmt
= SSA_NAME_DEF_STMT (name
);
4466 if (is_gimple_assign (def_stmt
)
4467 && (gimple_assign_rhs_code (def_stmt
) == TRUTH_OR_EXPR
4468 /* For BIT_IOR_EXPR only if NAME == 0 both operands have
4469 necessarily zero value. */
4470 || (comp_code
== EQ_EXPR
4471 && (gimple_assign_rhs_code (def_stmt
) == BIT_IOR_EXPR
))))
4473 tree op0
= gimple_assign_rhs1 (def_stmt
);
4474 tree op1
= gimple_assign_rhs2 (def_stmt
);
4475 retval
|= register_edge_assert_for_1 (op0
, EQ_EXPR
, e
, si
);
4476 retval
|= register_edge_assert_for_1 (op1
, EQ_EXPR
, e
, si
);
4484 /* Determine whether the outgoing edges of BB should receive an
4485 ASSERT_EXPR for each of the operands of BB's LAST statement.
4486 The last statement of BB must be a COND_EXPR.
4488 If any of the sub-graphs rooted at BB have an interesting use of
4489 the predicate operands, an assert location node is added to the
4490 list of assertions for the corresponding operands. */
4493 find_conditional_asserts (basic_block bb
, gimple last
)
4496 gimple_stmt_iterator bsi
;
4502 need_assert
= false;
4503 bsi
= gsi_for_stmt (last
);
4505 /* Look for uses of the operands in each of the sub-graphs
4506 rooted at BB. We need to check each of the outgoing edges
4507 separately, so that we know what kind of ASSERT_EXPR to
4509 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
4514 /* Register the necessary assertions for each operand in the
4515 conditional predicate. */
4516 FOR_EACH_SSA_TREE_OPERAND (op
, last
, iter
, SSA_OP_USE
)
4518 need_assert
|= register_edge_assert_for (op
, e
, bsi
,
4519 gimple_cond_code (last
),
4520 gimple_cond_lhs (last
),
4521 gimple_cond_rhs (last
));
4528 /* Compare two case labels sorting first by the destination label uid
4529 and then by the case value. */
4532 compare_case_labels (const void *p1
, const void *p2
)
4534 const_tree
const case1
= *(const_tree
const*)p1
;
4535 const_tree
const case2
= *(const_tree
const*)p2
;
4536 unsigned int uid1
= DECL_UID (CASE_LABEL (case1
));
4537 unsigned int uid2
= DECL_UID (CASE_LABEL (case2
));
4541 else if (uid1
== uid2
)
4543 /* Make sure the default label is first in a group. */
4544 if (!CASE_LOW (case1
))
4546 else if (!CASE_LOW (case2
))
4549 return tree_int_cst_compare (CASE_LOW (case1
), CASE_LOW (case2
));
4555 /* Determine whether the outgoing edges of BB should receive an
4556 ASSERT_EXPR for each of the operands of BB's LAST statement.
4557 The last statement of BB must be a SWITCH_EXPR.
4559 If any of the sub-graphs rooted at BB have an interesting use of
4560 the predicate operands, an assert location node is added to the
4561 list of assertions for the corresponding operands. */
4564 find_switch_asserts (basic_block bb
, gimple last
)
4567 gimple_stmt_iterator bsi
;
4571 size_t n
= gimple_switch_num_labels(last
);
4572 #if GCC_VERSION >= 4000
4575 /* Work around GCC 3.4 bug (PR 37086). */
4576 volatile unsigned int idx
;
4579 need_assert
= false;
4580 bsi
= gsi_for_stmt (last
);
4581 op
= gimple_switch_index (last
);
4582 if (TREE_CODE (op
) != SSA_NAME
)
4585 /* Build a vector of case labels sorted by destination label. */
4586 vec2
= make_tree_vec (n
);
4587 for (idx
= 0; idx
< n
; ++idx
)
4588 TREE_VEC_ELT (vec2
, idx
) = gimple_switch_label (last
, idx
);
4589 qsort (&TREE_VEC_ELT (vec2
, 0), n
, sizeof (tree
), compare_case_labels
);
4591 for (idx
= 0; idx
< n
; ++idx
)
4594 tree cl
= TREE_VEC_ELT (vec2
, idx
);
4596 min
= CASE_LOW (cl
);
4597 max
= CASE_HIGH (cl
);
4599 /* If there are multiple case labels with the same destination
4600 we need to combine them to a single value range for the edge. */
4602 && CASE_LABEL (cl
) == CASE_LABEL (TREE_VEC_ELT (vec2
, idx
+ 1)))
4604 /* Skip labels until the last of the group. */
4608 && CASE_LABEL (cl
) == CASE_LABEL (TREE_VEC_ELT (vec2
, idx
)));
4611 /* Pick up the maximum of the case label range. */
4612 if (CASE_HIGH (TREE_VEC_ELT (vec2
, idx
)))
4613 max
= CASE_HIGH (TREE_VEC_ELT (vec2
, idx
));
4615 max
= CASE_LOW (TREE_VEC_ELT (vec2
, idx
));
4618 /* Nothing to do if the range includes the default label until we
4619 can register anti-ranges. */
4620 if (min
== NULL_TREE
)
4623 /* Find the edge to register the assert expr on. */
4624 e
= find_edge (bb
, label_to_block (CASE_LABEL (cl
)));
4626 /* Register the necessary assertions for the operand in the
4628 need_assert
|= register_edge_assert_for (op
, e
, bsi
,
4629 max
? GE_EXPR
: EQ_EXPR
,
4631 fold_convert (TREE_TYPE (op
),
4635 need_assert
|= register_edge_assert_for (op
, e
, bsi
, LE_EXPR
,
4637 fold_convert (TREE_TYPE (op
),
4646 /* Traverse all the statements in block BB looking for statements that
4647 may generate useful assertions for the SSA names in their operand.
4648 If a statement produces a useful assertion A for name N_i, then the
4649 list of assertions already generated for N_i is scanned to
4650 determine if A is actually needed.
4652 If N_i already had the assertion A at a location dominating the
4653 current location, then nothing needs to be done. Otherwise, the
4654 new location for A is recorded instead.
4656 1- For every statement S in BB, all the variables used by S are
4657 added to bitmap FOUND_IN_SUBGRAPH.
4659 2- If statement S uses an operand N in a way that exposes a known
4660 value range for N, then if N was not already generated by an
4661 ASSERT_EXPR, create a new assert location for N. For instance,
4662 if N is a pointer and the statement dereferences it, we can
4663 assume that N is not NULL.
4665 3- COND_EXPRs are a special case of #2. We can derive range
4666 information from the predicate but need to insert different
4667 ASSERT_EXPRs for each of the sub-graphs rooted at the
4668 conditional block. If the last statement of BB is a conditional
4669 expression of the form 'X op Y', then
4671 a) Remove X and Y from the set FOUND_IN_SUBGRAPH.
4673 b) If the conditional is the only entry point to the sub-graph
4674 corresponding to the THEN_CLAUSE, recurse into it. On
4675 return, if X and/or Y are marked in FOUND_IN_SUBGRAPH, then
4676 an ASSERT_EXPR is added for the corresponding variable.
4678 c) Repeat step (b) on the ELSE_CLAUSE.
4680 d) Mark X and Y in FOUND_IN_SUBGRAPH.
4689 In this case, an assertion on the THEN clause is useful to
4690 determine that 'a' is always 9 on that edge. However, an assertion
4691 on the ELSE clause would be unnecessary.
4693 4- If BB does not end in a conditional expression, then we recurse
4694 into BB's dominator children.
4696 At the end of the recursive traversal, every SSA name will have a
4697 list of locations where ASSERT_EXPRs should be added. When a new
4698 location for name N is found, it is registered by calling
4699 register_new_assert_for. That function keeps track of all the
4700 registered assertions to prevent adding unnecessary assertions.
4701 For instance, if a pointer P_4 is dereferenced more than once in a
4702 dominator tree, only the location dominating all the dereference of
4703 P_4 will receive an ASSERT_EXPR.
4705 If this function returns true, then it means that there are names
4706 for which we need to generate ASSERT_EXPRs. Those assertions are
4707 inserted by process_assert_insertions. */
4710 find_assert_locations_1 (basic_block bb
, sbitmap live
)
4712 gimple_stmt_iterator si
;
4717 need_assert
= false;
4718 last
= last_stmt (bb
);
4720 /* If BB's last statement is a conditional statement involving integer
4721 operands, determine if we need to add ASSERT_EXPRs. */
4723 && gimple_code (last
) == GIMPLE_COND
4724 && !fp_predicate (last
)
4725 && !ZERO_SSA_OPERANDS (last
, SSA_OP_USE
))
4726 need_assert
|= find_conditional_asserts (bb
, last
);
4728 /* If BB's last statement is a switch statement involving integer
4729 operands, determine if we need to add ASSERT_EXPRs. */
4731 && gimple_code (last
) == GIMPLE_SWITCH
4732 && !ZERO_SSA_OPERANDS (last
, SSA_OP_USE
))
4733 need_assert
|= find_switch_asserts (bb
, last
);
4735 /* Traverse all the statements in BB marking used names and looking
4736 for statements that may infer assertions for their used operands. */
4737 for (si
= gsi_start_bb (bb
); !gsi_end_p (si
); gsi_next (&si
))
4743 stmt
= gsi_stmt (si
);
4745 if (is_gimple_debug (stmt
))
4748 /* See if we can derive an assertion for any of STMT's operands. */
4749 FOR_EACH_SSA_TREE_OPERAND (op
, stmt
, i
, SSA_OP_USE
)
4752 enum tree_code comp_code
;
4754 /* Mark OP in our live bitmap. */
4755 SET_BIT (live
, SSA_NAME_VERSION (op
));
4757 /* If OP is used in such a way that we can infer a value
4758 range for it, and we don't find a previous assertion for
4759 it, create a new assertion location node for OP. */
4760 if (infer_value_range (stmt
, op
, &comp_code
, &value
))
4762 /* If we are able to infer a nonzero value range for OP,
4763 then walk backwards through the use-def chain to see if OP
4764 was set via a typecast.
4766 If so, then we can also infer a nonzero value range
4767 for the operand of the NOP_EXPR. */
4768 if (comp_code
== NE_EXPR
&& integer_zerop (value
))
4771 gimple def_stmt
= SSA_NAME_DEF_STMT (t
);
4773 while (is_gimple_assign (def_stmt
)
4774 && gimple_assign_rhs_code (def_stmt
) == NOP_EXPR
4776 (gimple_assign_rhs1 (def_stmt
)) == SSA_NAME
4778 (TREE_TYPE (gimple_assign_rhs1 (def_stmt
))))
4780 t
= gimple_assign_rhs1 (def_stmt
);
4781 def_stmt
= SSA_NAME_DEF_STMT (t
);
4783 /* Note we want to register the assert for the
4784 operand of the NOP_EXPR after SI, not after the
4786 if (! has_single_use (t
))
4788 register_new_assert_for (t
, t
, comp_code
, value
,
4795 /* If OP is used only once, namely in this STMT, don't
4796 bother creating an ASSERT_EXPR for it. Such an
4797 ASSERT_EXPR would do nothing but increase compile time. */
4798 if (!has_single_use (op
))
4800 register_new_assert_for (op
, op
, comp_code
, value
,
4808 /* Traverse all PHI nodes in BB marking used operands. */
4809 for (si
= gsi_start_phis (bb
); !gsi_end_p(si
); gsi_next (&si
))
4811 use_operand_p arg_p
;
4813 phi
= gsi_stmt (si
);
4815 FOR_EACH_PHI_ARG (arg_p
, phi
, i
, SSA_OP_USE
)
4817 tree arg
= USE_FROM_PTR (arg_p
);
4818 if (TREE_CODE (arg
) == SSA_NAME
)
4819 SET_BIT (live
, SSA_NAME_VERSION (arg
));
4826 /* Do an RPO walk over the function computing SSA name liveness
4827 on-the-fly and deciding on assert expressions to insert.
4828 Returns true if there are assert expressions to be inserted. */
4831 find_assert_locations (void)
4833 int *rpo
= XCNEWVEC (int, last_basic_block
+ NUM_FIXED_BLOCKS
);
4834 int *bb_rpo
= XCNEWVEC (int, last_basic_block
+ NUM_FIXED_BLOCKS
);
4835 int *last_rpo
= XCNEWVEC (int, last_basic_block
+ NUM_FIXED_BLOCKS
);
4839 live
= XCNEWVEC (sbitmap
, last_basic_block
+ NUM_FIXED_BLOCKS
);
4840 rpo_cnt
= pre_and_rev_post_order_compute (NULL
, rpo
, false);
4841 for (i
= 0; i
< rpo_cnt
; ++i
)
4844 need_asserts
= false;
4845 for (i
= rpo_cnt
-1; i
>= 0; --i
)
4847 basic_block bb
= BASIC_BLOCK (rpo
[i
]);
4853 live
[rpo
[i
]] = sbitmap_alloc (num_ssa_names
);
4854 sbitmap_zero (live
[rpo
[i
]]);
4857 /* Process BB and update the live information with uses in
4859 need_asserts
|= find_assert_locations_1 (bb
, live
[rpo
[i
]]);
4861 /* Merge liveness into the predecessor blocks and free it. */
4862 if (!sbitmap_empty_p (live
[rpo
[i
]]))
4865 FOR_EACH_EDGE (e
, ei
, bb
->preds
)
4867 int pred
= e
->src
->index
;
4868 if (e
->flags
& EDGE_DFS_BACK
)
4873 live
[pred
] = sbitmap_alloc (num_ssa_names
);
4874 sbitmap_zero (live
[pred
]);
4876 sbitmap_a_or_b (live
[pred
], live
[pred
], live
[rpo
[i
]]);
4878 if (bb_rpo
[pred
] < pred_rpo
)
4879 pred_rpo
= bb_rpo
[pred
];
4882 /* Record the RPO number of the last visited block that needs
4883 live information from this block. */
4884 last_rpo
[rpo
[i
]] = pred_rpo
;
4888 sbitmap_free (live
[rpo
[i
]]);
4889 live
[rpo
[i
]] = NULL
;
4892 /* We can free all successors live bitmaps if all their
4893 predecessors have been visited already. */
4894 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
4895 if (last_rpo
[e
->dest
->index
] == i
4896 && live
[e
->dest
->index
])
4898 sbitmap_free (live
[e
->dest
->index
]);
4899 live
[e
->dest
->index
] = NULL
;
4904 XDELETEVEC (bb_rpo
);
4905 XDELETEVEC (last_rpo
);
4906 for (i
= 0; i
< last_basic_block
+ NUM_FIXED_BLOCKS
; ++i
)
4908 sbitmap_free (live
[i
]);
4911 return need_asserts
;
4914 /* Create an ASSERT_EXPR for NAME and insert it in the location
4915 indicated by LOC. Return true if we made any edge insertions. */
4918 process_assert_insertions_for (tree name
, assert_locus_t loc
)
4920 /* Build the comparison expression NAME_i COMP_CODE VAL. */
4927 /* If we have X <=> X do not insert an assert expr for that. */
4928 if (loc
->expr
== loc
->val
)
4931 cond
= build2 (loc
->comp_code
, boolean_type_node
, loc
->expr
, loc
->val
);
4932 assert_stmt
= build_assert_expr_for (cond
, name
);
4935 /* We have been asked to insert the assertion on an edge. This
4936 is used only by COND_EXPR and SWITCH_EXPR assertions. */
4937 #if defined ENABLE_CHECKING
4938 gcc_assert (gimple_code (gsi_stmt (loc
->si
)) == GIMPLE_COND
4939 || gimple_code (gsi_stmt (loc
->si
)) == GIMPLE_SWITCH
);
4942 gsi_insert_on_edge (loc
->e
, assert_stmt
);
4946 /* Otherwise, we can insert right after LOC->SI iff the
4947 statement must not be the last statement in the block. */
4948 stmt
= gsi_stmt (loc
->si
);
4949 if (!stmt_ends_bb_p (stmt
))
4951 gsi_insert_after (&loc
->si
, assert_stmt
, GSI_SAME_STMT
);
4955 /* If STMT must be the last statement in BB, we can only insert new
4956 assertions on the non-abnormal edge out of BB. Note that since
4957 STMT is not control flow, there may only be one non-abnormal edge
4959 FOR_EACH_EDGE (e
, ei
, loc
->bb
->succs
)
4960 if (!(e
->flags
& EDGE_ABNORMAL
))
4962 gsi_insert_on_edge (e
, assert_stmt
);
4970 /* Process all the insertions registered for every name N_i registered
4971 in NEED_ASSERT_FOR. The list of assertions to be inserted are
4972 found in ASSERTS_FOR[i]. */
4975 process_assert_insertions (void)
4979 bool update_edges_p
= false;
4980 int num_asserts
= 0;
4982 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
4983 dump_all_asserts (dump_file
);
4985 EXECUTE_IF_SET_IN_BITMAP (need_assert_for
, 0, i
, bi
)
4987 assert_locus_t loc
= asserts_for
[i
];
4992 assert_locus_t next
= loc
->next
;
4993 update_edges_p
|= process_assert_insertions_for (ssa_name (i
), loc
);
5001 gsi_commit_edge_inserts ();
5003 statistics_counter_event (cfun
, "Number of ASSERT_EXPR expressions inserted",
5008 /* Traverse the flowgraph looking for conditional jumps to insert range
5009 expressions. These range expressions are meant to provide information
5010 to optimizations that need to reason in terms of value ranges. They
5011 will not be expanded into RTL. For instance, given:
5020 this pass will transform the code into:
5026 x = ASSERT_EXPR <x, x < y>
5031 y = ASSERT_EXPR <y, x <= y>
5035 The idea is that once copy and constant propagation have run, other
5036 optimizations will be able to determine what ranges of values can 'x'
5037 take in different paths of the code, simply by checking the reaching
5038 definition of 'x'. */
5041 insert_range_assertions (void)
5043 need_assert_for
= BITMAP_ALLOC (NULL
);
5044 asserts_for
= XCNEWVEC (assert_locus_t
, num_ssa_names
);
5046 calculate_dominance_info (CDI_DOMINATORS
);
5048 if (find_assert_locations ())
5050 process_assert_insertions ();
5051 update_ssa (TODO_update_ssa_no_phi
);
5054 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
5056 fprintf (dump_file
, "\nSSA form after inserting ASSERT_EXPRs\n");
5057 dump_function_to_file (current_function_decl
, dump_file
, dump_flags
);
5061 BITMAP_FREE (need_assert_for
);
5064 /* Checks one ARRAY_REF in REF, located at LOCUS. Ignores flexible arrays
5065 and "struct" hacks. If VRP can determine that the
5066 array subscript is a constant, check if it is outside valid
5067 range. If the array subscript is a RANGE, warn if it is
5068 non-overlapping with valid range.
5069 IGNORE_OFF_BY_ONE is true if the ARRAY_REF is inside a ADDR_EXPR. */
5072 check_array_ref (location_t location
, tree ref
, bool ignore_off_by_one
)
5074 value_range_t
* vr
= NULL
;
5075 tree low_sub
, up_sub
;
5076 tree low_bound
, up_bound
, up_bound_p1
;
5079 if (TREE_NO_WARNING (ref
))
5082 low_sub
= up_sub
= TREE_OPERAND (ref
, 1);
5083 up_bound
= array_ref_up_bound (ref
);
5085 /* Can not check flexible arrays. */
5087 || TREE_CODE (up_bound
) != INTEGER_CST
)
5090 /* Accesses to trailing arrays via pointers may access storage
5091 beyond the types array bounds. */
5092 base
= get_base_address (ref
);
5093 if (base
&& TREE_CODE (base
) == MEM_REF
)
5095 tree cref
, next
= NULL_TREE
;
5097 if (TREE_CODE (TREE_OPERAND (ref
, 0)) != COMPONENT_REF
)
5100 cref
= TREE_OPERAND (ref
, 0);
5101 if (TREE_CODE (TREE_TYPE (TREE_OPERAND (cref
, 0))) == RECORD_TYPE
)
5102 for (next
= TREE_CHAIN (TREE_OPERAND (cref
, 1));
5103 next
&& TREE_CODE (next
) != FIELD_DECL
;
5104 next
= TREE_CHAIN (next
))
5107 /* If this is the last field in a struct type or a field in a
5108 union type do not warn. */
5113 low_bound
= array_ref_low_bound (ref
);
5114 up_bound_p1
= int_const_binop (PLUS_EXPR
, up_bound
, integer_one_node
, 0);
5116 if (TREE_CODE (low_sub
) == SSA_NAME
)
5118 vr
= get_value_range (low_sub
);
5119 if (vr
->type
== VR_RANGE
|| vr
->type
== VR_ANTI_RANGE
)
5121 low_sub
= vr
->type
== VR_RANGE
? vr
->max
: vr
->min
;
5122 up_sub
= vr
->type
== VR_RANGE
? vr
->min
: vr
->max
;
5126 if (vr
&& vr
->type
== VR_ANTI_RANGE
)
5128 if (TREE_CODE (up_sub
) == INTEGER_CST
5129 && tree_int_cst_lt (up_bound
, up_sub
)
5130 && TREE_CODE (low_sub
) == INTEGER_CST
5131 && tree_int_cst_lt (low_sub
, low_bound
))
5133 warning_at (location
, OPT_Warray_bounds
,
5134 "array subscript is outside array bounds");
5135 TREE_NO_WARNING (ref
) = 1;
5138 else if (TREE_CODE (up_sub
) == INTEGER_CST
5139 && (ignore_off_by_one
5140 ? (tree_int_cst_lt (up_bound
, up_sub
)
5141 && !tree_int_cst_equal (up_bound_p1
, up_sub
))
5142 : (tree_int_cst_lt (up_bound
, up_sub
)
5143 || tree_int_cst_equal (up_bound_p1
, up_sub
))))
5145 warning_at (location
, OPT_Warray_bounds
,
5146 "array subscript is above array bounds");
5147 TREE_NO_WARNING (ref
) = 1;
5149 else if (TREE_CODE (low_sub
) == INTEGER_CST
5150 && tree_int_cst_lt (low_sub
, low_bound
))
5152 warning_at (location
, OPT_Warray_bounds
,
5153 "array subscript is below array bounds");
5154 TREE_NO_WARNING (ref
) = 1;
5158 /* Searches if the expr T, located at LOCATION computes
5159 address of an ARRAY_REF, and call check_array_ref on it. */
5162 search_for_addr_array (tree t
, location_t location
)
5164 while (TREE_CODE (t
) == SSA_NAME
)
5166 gimple g
= SSA_NAME_DEF_STMT (t
);
5168 if (gimple_code (g
) != GIMPLE_ASSIGN
)
5171 if (get_gimple_rhs_class (gimple_assign_rhs_code (g
))
5172 != GIMPLE_SINGLE_RHS
)
5175 t
= gimple_assign_rhs1 (g
);
5179 /* We are only interested in addresses of ARRAY_REF's. */
5180 if (TREE_CODE (t
) != ADDR_EXPR
)
5183 /* Check each ARRAY_REFs in the reference chain. */
5186 if (TREE_CODE (t
) == ARRAY_REF
)
5187 check_array_ref (location
, t
, true /*ignore_off_by_one*/);
5189 t
= TREE_OPERAND (t
, 0);
5191 while (handled_component_p (t
));
5193 if (TREE_CODE (t
) == MEM_REF
5194 && TREE_CODE (TREE_OPERAND (t
, 0)) == ADDR_EXPR
5195 && !TREE_NO_WARNING (t
))
5197 tree tem
= TREE_OPERAND (TREE_OPERAND (t
, 0), 0);
5198 tree low_bound
, up_bound
, el_sz
;
5200 if (TREE_CODE (TREE_TYPE (tem
)) != ARRAY_TYPE
5201 || TREE_CODE (TREE_TYPE (TREE_TYPE (tem
))) == ARRAY_TYPE
5202 || !TYPE_DOMAIN (TREE_TYPE (tem
)))
5205 low_bound
= TYPE_MIN_VALUE (TYPE_DOMAIN (TREE_TYPE (tem
)));
5206 up_bound
= TYPE_MAX_VALUE (TYPE_DOMAIN (TREE_TYPE (tem
)));
5207 el_sz
= TYPE_SIZE_UNIT (TREE_TYPE (TREE_TYPE (tem
)));
5209 || TREE_CODE (low_bound
) != INTEGER_CST
5211 || TREE_CODE (up_bound
) != INTEGER_CST
5213 || TREE_CODE (el_sz
) != INTEGER_CST
)
5216 idx
= mem_ref_offset (t
);
5217 idx
= double_int_sdiv (idx
, tree_to_double_int (el_sz
), TRUNC_DIV_EXPR
);
5218 if (double_int_scmp (idx
, double_int_zero
) < 0)
5220 warning_at (location
, OPT_Warray_bounds
,
5221 "array subscript is below array bounds");
5222 TREE_NO_WARNING (t
) = 1;
5224 else if (double_int_scmp (idx
,
5227 (tree_to_double_int (up_bound
),
5229 (tree_to_double_int (low_bound
))),
5230 double_int_one
)) > 0)
5232 warning_at (location
, OPT_Warray_bounds
,
5233 "array subscript is above array bounds");
5234 TREE_NO_WARNING (t
) = 1;
5239 /* walk_tree() callback that checks if *TP is
5240 an ARRAY_REF inside an ADDR_EXPR (in which an array
5241 subscript one outside the valid range is allowed). Call
5242 check_array_ref for each ARRAY_REF found. The location is
5246 check_array_bounds (tree
*tp
, int *walk_subtree
, void *data
)
5249 struct walk_stmt_info
*wi
= (struct walk_stmt_info
*) data
;
5250 location_t location
;
5252 if (EXPR_HAS_LOCATION (t
))
5253 location
= EXPR_LOCATION (t
);
5256 location_t
*locp
= (location_t
*) wi
->info
;
5260 *walk_subtree
= TRUE
;
5262 if (TREE_CODE (t
) == ARRAY_REF
)
5263 check_array_ref (location
, t
, false /*ignore_off_by_one*/);
5265 if (TREE_CODE (t
) == MEM_REF
5266 || (TREE_CODE (t
) == RETURN_EXPR
&& TREE_OPERAND (t
, 0)))
5267 search_for_addr_array (TREE_OPERAND (t
, 0), location
);
5269 if (TREE_CODE (t
) == ADDR_EXPR
)
5270 *walk_subtree
= FALSE
;
5275 /* Walk over all statements of all reachable BBs and call check_array_bounds
5279 check_all_array_refs (void)
5282 gimple_stmt_iterator si
;
5288 bool executable
= false;
5290 /* Skip blocks that were found to be unreachable. */
5291 FOR_EACH_EDGE (e
, ei
, bb
->preds
)
5292 executable
|= !!(e
->flags
& EDGE_EXECUTABLE
);
5296 for (si
= gsi_start_bb (bb
); !gsi_end_p (si
); gsi_next (&si
))
5298 gimple stmt
= gsi_stmt (si
);
5299 struct walk_stmt_info wi
;
5300 if (!gimple_has_location (stmt
))
5303 if (is_gimple_call (stmt
))
5306 size_t n
= gimple_call_num_args (stmt
);
5307 for (i
= 0; i
< n
; i
++)
5309 tree arg
= gimple_call_arg (stmt
, i
);
5310 search_for_addr_array (arg
, gimple_location (stmt
));
5315 memset (&wi
, 0, sizeof (wi
));
5316 wi
.info
= CONST_CAST (void *, (const void *)
5317 gimple_location_ptr (stmt
));
5319 walk_gimple_op (gsi_stmt (si
),
5327 /* Convert range assertion expressions into the implied copies and
5328 copy propagate away the copies. Doing the trivial copy propagation
5329 here avoids the need to run the full copy propagation pass after
5332 FIXME, this will eventually lead to copy propagation removing the
5333 names that had useful range information attached to them. For
5334 instance, if we had the assertion N_i = ASSERT_EXPR <N_j, N_j > 3>,
5335 then N_i will have the range [3, +INF].
5337 However, by converting the assertion into the implied copy
5338 operation N_i = N_j, we will then copy-propagate N_j into the uses
5339 of N_i and lose the range information. We may want to hold on to
5340 ASSERT_EXPRs a little while longer as the ranges could be used in
5341 things like jump threading.
5343 The problem with keeping ASSERT_EXPRs around is that passes after
5344 VRP need to handle them appropriately.
5346 Another approach would be to make the range information a first
5347 class property of the SSA_NAME so that it can be queried from
5348 any pass. This is made somewhat more complex by the need for
5349 multiple ranges to be associated with one SSA_NAME. */
5352 remove_range_assertions (void)
5355 gimple_stmt_iterator si
;
5357 /* Note that the BSI iterator bump happens at the bottom of the
5358 loop and no bump is necessary if we're removing the statement
5359 referenced by the current BSI. */
5361 for (si
= gsi_start_bb (bb
); !gsi_end_p (si
);)
5363 gimple stmt
= gsi_stmt (si
);
5366 if (is_gimple_assign (stmt
)
5367 && gimple_assign_rhs_code (stmt
) == ASSERT_EXPR
)
5369 tree rhs
= gimple_assign_rhs1 (stmt
);
5371 tree cond
= fold (ASSERT_EXPR_COND (rhs
));
5372 use_operand_p use_p
;
5373 imm_use_iterator iter
;
5375 gcc_assert (cond
!= boolean_false_node
);
5377 /* Propagate the RHS into every use of the LHS. */
5378 var
= ASSERT_EXPR_VAR (rhs
);
5379 FOR_EACH_IMM_USE_STMT (use_stmt
, iter
,
5380 gimple_assign_lhs (stmt
))
5381 FOR_EACH_IMM_USE_ON_STMT (use_p
, iter
)
5383 SET_USE (use_p
, var
);
5384 gcc_assert (TREE_CODE (var
) == SSA_NAME
);
5387 /* And finally, remove the copy, it is not needed. */
5388 gsi_remove (&si
, true);
5389 release_defs (stmt
);
5397 /* Return true if STMT is interesting for VRP. */
5400 stmt_interesting_for_vrp (gimple stmt
)
5402 if (gimple_code (stmt
) == GIMPLE_PHI
5403 && is_gimple_reg (gimple_phi_result (stmt
))
5404 && (INTEGRAL_TYPE_P (TREE_TYPE (gimple_phi_result (stmt
)))
5405 || POINTER_TYPE_P (TREE_TYPE (gimple_phi_result (stmt
)))))
5407 else if (is_gimple_assign (stmt
) || is_gimple_call (stmt
))
5409 tree lhs
= gimple_get_lhs (stmt
);
5411 /* In general, assignments with virtual operands are not useful
5412 for deriving ranges, with the obvious exception of calls to
5413 builtin functions. */
5414 if (lhs
&& TREE_CODE (lhs
) == SSA_NAME
5415 && (INTEGRAL_TYPE_P (TREE_TYPE (lhs
))
5416 || POINTER_TYPE_P (TREE_TYPE (lhs
)))
5417 && ((is_gimple_call (stmt
)
5418 && gimple_call_fndecl (stmt
) != NULL_TREE
5419 && DECL_IS_BUILTIN (gimple_call_fndecl (stmt
)))
5420 || !gimple_vuse (stmt
)))
5423 else if (gimple_code (stmt
) == GIMPLE_COND
5424 || gimple_code (stmt
) == GIMPLE_SWITCH
)
5431 /* Initialize local data structures for VRP. */
5434 vrp_initialize (void)
5438 vr_value
= XCNEWVEC (value_range_t
*, num_ssa_names
);
5439 vr_phi_edge_counts
= XCNEWVEC (int, num_ssa_names
);
5443 gimple_stmt_iterator si
;
5445 for (si
= gsi_start_phis (bb
); !gsi_end_p (si
); gsi_next (&si
))
5447 gimple phi
= gsi_stmt (si
);
5448 if (!stmt_interesting_for_vrp (phi
))
5450 tree lhs
= PHI_RESULT (phi
);
5451 set_value_range_to_varying (get_value_range (lhs
));
5452 prop_set_simulate_again (phi
, false);
5455 prop_set_simulate_again (phi
, true);
5458 for (si
= gsi_start_bb (bb
); !gsi_end_p (si
); gsi_next (&si
))
5460 gimple stmt
= gsi_stmt (si
);
5462 /* If the statement is a control insn, then we do not
5463 want to avoid simulating the statement once. Failure
5464 to do so means that those edges will never get added. */
5465 if (stmt_ends_bb_p (stmt
))
5466 prop_set_simulate_again (stmt
, true);
5467 else if (!stmt_interesting_for_vrp (stmt
))
5471 FOR_EACH_SSA_TREE_OPERAND (def
, stmt
, i
, SSA_OP_DEF
)
5472 set_value_range_to_varying (get_value_range (def
));
5473 prop_set_simulate_again (stmt
, false);
5476 prop_set_simulate_again (stmt
, true);
5482 /* Visit assignment STMT. If it produces an interesting range, record
5483 the SSA name in *OUTPUT_P. */
5485 static enum ssa_prop_result
5486 vrp_visit_assignment_or_call (gimple stmt
, tree
*output_p
)
5490 enum gimple_code code
= gimple_code (stmt
);
5491 lhs
= gimple_get_lhs (stmt
);
5493 /* We only keep track of ranges in integral and pointer types. */
5494 if (TREE_CODE (lhs
) == SSA_NAME
5495 && ((INTEGRAL_TYPE_P (TREE_TYPE (lhs
))
5496 /* It is valid to have NULL MIN/MAX values on a type. See
5497 build_range_type. */
5498 && TYPE_MIN_VALUE (TREE_TYPE (lhs
))
5499 && TYPE_MAX_VALUE (TREE_TYPE (lhs
)))
5500 || POINTER_TYPE_P (TREE_TYPE (lhs
))))
5502 value_range_t new_vr
= { VR_UNDEFINED
, NULL_TREE
, NULL_TREE
, NULL
};
5504 if (code
== GIMPLE_CALL
)
5505 extract_range_basic (&new_vr
, stmt
);
5507 extract_range_from_assignment (&new_vr
, stmt
);
5509 if (update_value_range (lhs
, &new_vr
))
5513 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
5515 fprintf (dump_file
, "Found new range for ");
5516 print_generic_expr (dump_file
, lhs
, 0);
5517 fprintf (dump_file
, ": ");
5518 dump_value_range (dump_file
, &new_vr
);
5519 fprintf (dump_file
, "\n\n");
5522 if (new_vr
.type
== VR_VARYING
)
5523 return SSA_PROP_VARYING
;
5525 return SSA_PROP_INTERESTING
;
5528 return SSA_PROP_NOT_INTERESTING
;
5531 /* Every other statement produces no useful ranges. */
5532 FOR_EACH_SSA_TREE_OPERAND (def
, stmt
, iter
, SSA_OP_DEF
)
5533 set_value_range_to_varying (get_value_range (def
));
5535 return SSA_PROP_VARYING
;
5538 /* Helper that gets the value range of the SSA_NAME with version I
5539 or a symbolic range containing the SSA_NAME only if the value range
5540 is varying or undefined. */
5542 static inline value_range_t
5543 get_vr_for_comparison (int i
)
5545 value_range_t vr
= *(vr_value
[i
]);
5547 /* If name N_i does not have a valid range, use N_i as its own
5548 range. This allows us to compare against names that may
5549 have N_i in their ranges. */
5550 if (vr
.type
== VR_VARYING
|| vr
.type
== VR_UNDEFINED
)
5553 vr
.min
= ssa_name (i
);
5554 vr
.max
= ssa_name (i
);
5560 /* Compare all the value ranges for names equivalent to VAR with VAL
5561 using comparison code COMP. Return the same value returned by
5562 compare_range_with_value, including the setting of
5563 *STRICT_OVERFLOW_P. */
5566 compare_name_with_value (enum tree_code comp
, tree var
, tree val
,
5567 bool *strict_overflow_p
)
5573 int used_strict_overflow
;
5575 value_range_t equiv_vr
;
5577 /* Get the set of equivalences for VAR. */
5578 e
= get_value_range (var
)->equiv
;
5580 /* Start at -1. Set it to 0 if we do a comparison without relying
5581 on overflow, or 1 if all comparisons rely on overflow. */
5582 used_strict_overflow
= -1;
5584 /* Compare vars' value range with val. */
5585 equiv_vr
= get_vr_for_comparison (SSA_NAME_VERSION (var
));
5587 retval
= compare_range_with_value (comp
, &equiv_vr
, val
, &sop
);
5589 used_strict_overflow
= sop
? 1 : 0;
5591 /* If the equiv set is empty we have done all work we need to do. */
5595 && used_strict_overflow
> 0)
5596 *strict_overflow_p
= true;
5600 EXECUTE_IF_SET_IN_BITMAP (e
, 0, i
, bi
)
5602 equiv_vr
= get_vr_for_comparison (i
);
5604 t
= compare_range_with_value (comp
, &equiv_vr
, val
, &sop
);
5607 /* If we get different answers from different members
5608 of the equivalence set this check must be in a dead
5609 code region. Folding it to a trap representation
5610 would be correct here. For now just return don't-know. */
5620 used_strict_overflow
= 0;
5621 else if (used_strict_overflow
< 0)
5622 used_strict_overflow
= 1;
5627 && used_strict_overflow
> 0)
5628 *strict_overflow_p
= true;
5634 /* Given a comparison code COMP and names N1 and N2, compare all the
5635 ranges equivalent to N1 against all the ranges equivalent to N2
5636 to determine the value of N1 COMP N2. Return the same value
5637 returned by compare_ranges. Set *STRICT_OVERFLOW_P to indicate
5638 whether we relied on an overflow infinity in the comparison. */
5642 compare_names (enum tree_code comp
, tree n1
, tree n2
,
5643 bool *strict_overflow_p
)
5647 bitmap_iterator bi1
, bi2
;
5649 int used_strict_overflow
;
5650 static bitmap_obstack
*s_obstack
= NULL
;
5651 static bitmap s_e1
= NULL
, s_e2
= NULL
;
5653 /* Compare the ranges of every name equivalent to N1 against the
5654 ranges of every name equivalent to N2. */
5655 e1
= get_value_range (n1
)->equiv
;
5656 e2
= get_value_range (n2
)->equiv
;
5658 /* Use the fake bitmaps if e1 or e2 are not available. */
5659 if (s_obstack
== NULL
)
5661 s_obstack
= XNEW (bitmap_obstack
);
5662 bitmap_obstack_initialize (s_obstack
);
5663 s_e1
= BITMAP_ALLOC (s_obstack
);
5664 s_e2
= BITMAP_ALLOC (s_obstack
);
5671 /* Add N1 and N2 to their own set of equivalences to avoid
5672 duplicating the body of the loop just to check N1 and N2
5674 bitmap_set_bit (e1
, SSA_NAME_VERSION (n1
));
5675 bitmap_set_bit (e2
, SSA_NAME_VERSION (n2
));
5677 /* If the equivalence sets have a common intersection, then the two
5678 names can be compared without checking their ranges. */
5679 if (bitmap_intersect_p (e1
, e2
))
5681 bitmap_clear_bit (e1
, SSA_NAME_VERSION (n1
));
5682 bitmap_clear_bit (e2
, SSA_NAME_VERSION (n2
));
5684 return (comp
== EQ_EXPR
|| comp
== GE_EXPR
|| comp
== LE_EXPR
)
5686 : boolean_false_node
;
5689 /* Start at -1. Set it to 0 if we do a comparison without relying
5690 on overflow, or 1 if all comparisons rely on overflow. */
5691 used_strict_overflow
= -1;
5693 /* Otherwise, compare all the equivalent ranges. First, add N1 and
5694 N2 to their own set of equivalences to avoid duplicating the body
5695 of the loop just to check N1 and N2 ranges. */
5696 EXECUTE_IF_SET_IN_BITMAP (e1
, 0, i1
, bi1
)
5698 value_range_t vr1
= get_vr_for_comparison (i1
);
5700 t
= retval
= NULL_TREE
;
5701 EXECUTE_IF_SET_IN_BITMAP (e2
, 0, i2
, bi2
)
5705 value_range_t vr2
= get_vr_for_comparison (i2
);
5707 t
= compare_ranges (comp
, &vr1
, &vr2
, &sop
);
5710 /* If we get different answers from different members
5711 of the equivalence set this check must be in a dead
5712 code region. Folding it to a trap representation
5713 would be correct here. For now just return don't-know. */
5717 bitmap_clear_bit (e1
, SSA_NAME_VERSION (n1
));
5718 bitmap_clear_bit (e2
, SSA_NAME_VERSION (n2
));
5724 used_strict_overflow
= 0;
5725 else if (used_strict_overflow
< 0)
5726 used_strict_overflow
= 1;
5732 bitmap_clear_bit (e1
, SSA_NAME_VERSION (n1
));
5733 bitmap_clear_bit (e2
, SSA_NAME_VERSION (n2
));
5734 if (used_strict_overflow
> 0)
5735 *strict_overflow_p
= true;
5740 /* None of the equivalent ranges are useful in computing this
5742 bitmap_clear_bit (e1
, SSA_NAME_VERSION (n1
));
5743 bitmap_clear_bit (e2
, SSA_NAME_VERSION (n2
));
5747 /* Helper function for vrp_evaluate_conditional_warnv. */
5750 vrp_evaluate_conditional_warnv_with_ops_using_ranges (enum tree_code code
,
5752 bool * strict_overflow_p
)
5754 value_range_t
*vr0
, *vr1
;
5756 vr0
= (TREE_CODE (op0
) == SSA_NAME
) ? get_value_range (op0
) : NULL
;
5757 vr1
= (TREE_CODE (op1
) == SSA_NAME
) ? get_value_range (op1
) : NULL
;
5760 return compare_ranges (code
, vr0
, vr1
, strict_overflow_p
);
5761 else if (vr0
&& vr1
== NULL
)
5762 return compare_range_with_value (code
, vr0
, op1
, strict_overflow_p
);
5763 else if (vr0
== NULL
&& vr1
)
5764 return (compare_range_with_value
5765 (swap_tree_comparison (code
), vr1
, op0
, strict_overflow_p
));
5769 /* Helper function for vrp_evaluate_conditional_warnv. */
5772 vrp_evaluate_conditional_warnv_with_ops (enum tree_code code
, tree op0
,
5773 tree op1
, bool use_equiv_p
,
5774 bool *strict_overflow_p
, bool *only_ranges
)
5778 *only_ranges
= true;
5780 /* We only deal with integral and pointer types. */
5781 if (!INTEGRAL_TYPE_P (TREE_TYPE (op0
))
5782 && !POINTER_TYPE_P (TREE_TYPE (op0
)))
5788 && (ret
= vrp_evaluate_conditional_warnv_with_ops_using_ranges
5789 (code
, op0
, op1
, strict_overflow_p
)))
5791 *only_ranges
= false;
5792 if (TREE_CODE (op0
) == SSA_NAME
&& TREE_CODE (op1
) == SSA_NAME
)
5793 return compare_names (code
, op0
, op1
, strict_overflow_p
);
5794 else if (TREE_CODE (op0
) == SSA_NAME
)
5795 return compare_name_with_value (code
, op0
, op1
, strict_overflow_p
);
5796 else if (TREE_CODE (op1
) == SSA_NAME
)
5797 return (compare_name_with_value
5798 (swap_tree_comparison (code
), op1
, op0
, strict_overflow_p
));
5801 return vrp_evaluate_conditional_warnv_with_ops_using_ranges (code
, op0
, op1
,
5806 /* Given (CODE OP0 OP1) within STMT, try to simplify it based on value range
5807 information. Return NULL if the conditional can not be evaluated.
5808 The ranges of all the names equivalent with the operands in COND
5809 will be used when trying to compute the value. If the result is
5810 based on undefined signed overflow, issue a warning if
5814 vrp_evaluate_conditional (enum tree_code code
, tree op0
, tree op1
, gimple stmt
)
5820 /* Some passes and foldings leak constants with overflow flag set
5821 into the IL. Avoid doing wrong things with these and bail out. */
5822 if ((TREE_CODE (op0
) == INTEGER_CST
5823 && TREE_OVERFLOW (op0
))
5824 || (TREE_CODE (op1
) == INTEGER_CST
5825 && TREE_OVERFLOW (op1
)))
5829 ret
= vrp_evaluate_conditional_warnv_with_ops (code
, op0
, op1
, true, &sop
,
5834 enum warn_strict_overflow_code wc
;
5835 const char* warnmsg
;
5837 if (is_gimple_min_invariant (ret
))
5839 wc
= WARN_STRICT_OVERFLOW_CONDITIONAL
;
5840 warnmsg
= G_("assuming signed overflow does not occur when "
5841 "simplifying conditional to constant");
5845 wc
= WARN_STRICT_OVERFLOW_COMPARISON
;
5846 warnmsg
= G_("assuming signed overflow does not occur when "
5847 "simplifying conditional");
5850 if (issue_strict_overflow_warning (wc
))
5852 location_t location
;
5854 if (!gimple_has_location (stmt
))
5855 location
= input_location
;
5857 location
= gimple_location (stmt
);
5858 warning_at (location
, OPT_Wstrict_overflow
, "%s", warnmsg
);
5862 if (warn_type_limits
5863 && ret
&& only_ranges
5864 && TREE_CODE_CLASS (code
) == tcc_comparison
5865 && TREE_CODE (op0
) == SSA_NAME
)
5867 /* If the comparison is being folded and the operand on the LHS
5868 is being compared against a constant value that is outside of
5869 the natural range of OP0's type, then the predicate will
5870 always fold regardless of the value of OP0. If -Wtype-limits
5871 was specified, emit a warning. */
5872 tree type
= TREE_TYPE (op0
);
5873 value_range_t
*vr0
= get_value_range (op0
);
5875 if (vr0
->type
!= VR_VARYING
5876 && INTEGRAL_TYPE_P (type
)
5877 && vrp_val_is_min (vr0
->min
)
5878 && vrp_val_is_max (vr0
->max
)
5879 && is_gimple_min_invariant (op1
))
5881 location_t location
;
5883 if (!gimple_has_location (stmt
))
5884 location
= input_location
;
5886 location
= gimple_location (stmt
);
5888 warning_at (location
, OPT_Wtype_limits
,
5890 ? G_("comparison always false "
5891 "due to limited range of data type")
5892 : G_("comparison always true "
5893 "due to limited range of data type"));
5901 /* Visit conditional statement STMT. If we can determine which edge
5902 will be taken out of STMT's basic block, record it in
5903 *TAKEN_EDGE_P and return SSA_PROP_INTERESTING. Otherwise, return
5904 SSA_PROP_VARYING. */
5906 static enum ssa_prop_result
5907 vrp_visit_cond_stmt (gimple stmt
, edge
*taken_edge_p
)
5912 *taken_edge_p
= NULL
;
5914 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
5919 fprintf (dump_file
, "\nVisiting conditional with predicate: ");
5920 print_gimple_stmt (dump_file
, stmt
, 0, 0);
5921 fprintf (dump_file
, "\nWith known ranges\n");
5923 FOR_EACH_SSA_TREE_OPERAND (use
, stmt
, i
, SSA_OP_USE
)
5925 fprintf (dump_file
, "\t");
5926 print_generic_expr (dump_file
, use
, 0);
5927 fprintf (dump_file
, ": ");
5928 dump_value_range (dump_file
, vr_value
[SSA_NAME_VERSION (use
)]);
5931 fprintf (dump_file
, "\n");
5934 /* Compute the value of the predicate COND by checking the known
5935 ranges of each of its operands.
5937 Note that we cannot evaluate all the equivalent ranges here
5938 because those ranges may not yet be final and with the current
5939 propagation strategy, we cannot determine when the value ranges
5940 of the names in the equivalence set have changed.
5942 For instance, given the following code fragment
5946 i_14 = ASSERT_EXPR <i_5, i_5 != 0>
5950 Assume that on the first visit to i_14, i_5 has the temporary
5951 range [8, 8] because the second argument to the PHI function is
5952 not yet executable. We derive the range ~[0, 0] for i_14 and the
5953 equivalence set { i_5 }. So, when we visit 'if (i_14 == 1)' for
5954 the first time, since i_14 is equivalent to the range [8, 8], we
5955 determine that the predicate is always false.
5957 On the next round of propagation, i_13 is determined to be
5958 VARYING, which causes i_5 to drop down to VARYING. So, another
5959 visit to i_14 is scheduled. In this second visit, we compute the
5960 exact same range and equivalence set for i_14, namely ~[0, 0] and
5961 { i_5 }. But we did not have the previous range for i_5
5962 registered, so vrp_visit_assignment thinks that the range for
5963 i_14 has not changed. Therefore, the predicate 'if (i_14 == 1)'
5964 is not visited again, which stops propagation from visiting
5965 statements in the THEN clause of that if().
5967 To properly fix this we would need to keep the previous range
5968 value for the names in the equivalence set. This way we would've
5969 discovered that from one visit to the other i_5 changed from
5970 range [8, 8] to VR_VARYING.
5972 However, fixing this apparent limitation may not be worth the
5973 additional checking. Testing on several code bases (GCC, DLV,
5974 MICO, TRAMP3D and SPEC2000) showed that doing this results in
5975 4 more predicates folded in SPEC. */
5978 val
= vrp_evaluate_conditional_warnv_with_ops (gimple_cond_code (stmt
),
5979 gimple_cond_lhs (stmt
),
5980 gimple_cond_rhs (stmt
),
5985 *taken_edge_p
= find_taken_edge (gimple_bb (stmt
), val
);
5988 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
5990 "\nIgnoring predicate evaluation because "
5991 "it assumes that signed overflow is undefined");
5996 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
5998 fprintf (dump_file
, "\nPredicate evaluates to: ");
5999 if (val
== NULL_TREE
)
6000 fprintf (dump_file
, "DON'T KNOW\n");
6002 print_generic_stmt (dump_file
, val
, 0);
6005 return (*taken_edge_p
) ? SSA_PROP_INTERESTING
: SSA_PROP_VARYING
;
6008 /* Searches the case label vector VEC for the index *IDX of the CASE_LABEL
6009 that includes the value VAL. The search is restricted to the range
6010 [START_IDX, n - 1] where n is the size of VEC.
6012 If there is a CASE_LABEL for VAL, its index is placed in IDX and true is
6015 If there is no CASE_LABEL for VAL and there is one that is larger than VAL,
6016 it is placed in IDX and false is returned.
6018 If VAL is larger than any CASE_LABEL, n is placed on IDX and false is
6022 find_case_label_index (gimple stmt
, size_t start_idx
, tree val
, size_t *idx
)
6024 size_t n
= gimple_switch_num_labels (stmt
);
6027 /* Find case label for minimum of the value range or the next one.
6028 At each iteration we are searching in [low, high - 1]. */
6030 for (low
= start_idx
, high
= n
; high
!= low
; )
6034 /* Note that i != high, so we never ask for n. */
6035 size_t i
= (high
+ low
) / 2;
6036 t
= gimple_switch_label (stmt
, i
);
6038 /* Cache the result of comparing CASE_LOW and val. */
6039 cmp
= tree_int_cst_compare (CASE_LOW (t
), val
);
6043 /* Ranges cannot be empty. */
6052 if (CASE_HIGH (t
) != NULL
6053 && tree_int_cst_compare (CASE_HIGH (t
), val
) >= 0)
6065 /* Searches the case label vector VEC for the range of CASE_LABELs that is used
6066 for values between MIN and MAX. The first index is placed in MIN_IDX. The
6067 last index is placed in MAX_IDX. If the range of CASE_LABELs is empty
6068 then MAX_IDX < MIN_IDX.
6069 Returns true if the default label is not needed. */
6072 find_case_label_range (gimple stmt
, tree min
, tree max
, size_t *min_idx
,
6076 bool min_take_default
= !find_case_label_index (stmt
, 1, min
, &i
);
6077 bool max_take_default
= !find_case_label_index (stmt
, i
, max
, &j
);
6081 && max_take_default
)
6083 /* Only the default case label reached.
6084 Return an empty range. */
6091 bool take_default
= min_take_default
|| max_take_default
;
6095 if (max_take_default
)
6098 /* If the case label range is continuous, we do not need
6099 the default case label. Verify that. */
6100 high
= CASE_LOW (gimple_switch_label (stmt
, i
));
6101 if (CASE_HIGH (gimple_switch_label (stmt
, i
)))
6102 high
= CASE_HIGH (gimple_switch_label (stmt
, i
));
6103 for (k
= i
+ 1; k
<= j
; ++k
)
6105 low
= CASE_LOW (gimple_switch_label (stmt
, k
));
6106 if (!integer_onep (int_const_binop (MINUS_EXPR
, low
, high
, 0)))
6108 take_default
= true;
6112 if (CASE_HIGH (gimple_switch_label (stmt
, k
)))
6113 high
= CASE_HIGH (gimple_switch_label (stmt
, k
));
6118 return !take_default
;
6122 /* Visit switch statement STMT. If we can determine which edge
6123 will be taken out of STMT's basic block, record it in
6124 *TAKEN_EDGE_P and return SSA_PROP_INTERESTING. Otherwise, return
6125 SSA_PROP_VARYING. */
6127 static enum ssa_prop_result
6128 vrp_visit_switch_stmt (gimple stmt
, edge
*taken_edge_p
)
6132 size_t i
= 0, j
= 0;
6135 *taken_edge_p
= NULL
;
6136 op
= gimple_switch_index (stmt
);
6137 if (TREE_CODE (op
) != SSA_NAME
)
6138 return SSA_PROP_VARYING
;
6140 vr
= get_value_range (op
);
6141 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
6143 fprintf (dump_file
, "\nVisiting switch expression with operand ");
6144 print_generic_expr (dump_file
, op
, 0);
6145 fprintf (dump_file
, " with known range ");
6146 dump_value_range (dump_file
, vr
);
6147 fprintf (dump_file
, "\n");
6150 if (vr
->type
!= VR_RANGE
6151 || symbolic_range_p (vr
))
6152 return SSA_PROP_VARYING
;
6154 /* Find the single edge that is taken from the switch expression. */
6155 take_default
= !find_case_label_range (stmt
, vr
->min
, vr
->max
, &i
, &j
);
6157 /* Check if the range spans no CASE_LABEL. If so, we only reach the default
6161 gcc_assert (take_default
);
6162 val
= gimple_switch_default_label (stmt
);
6166 /* Check if labels with index i to j and maybe the default label
6167 are all reaching the same label. */
6169 val
= gimple_switch_label (stmt
, i
);
6171 && CASE_LABEL (gimple_switch_default_label (stmt
))
6172 != CASE_LABEL (val
))
6174 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
6175 fprintf (dump_file
, " not a single destination for this "
6177 return SSA_PROP_VARYING
;
6179 for (++i
; i
<= j
; ++i
)
6181 if (CASE_LABEL (gimple_switch_label (stmt
, i
)) != CASE_LABEL (val
))
6183 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
6184 fprintf (dump_file
, " not a single destination for this "
6186 return SSA_PROP_VARYING
;
6191 *taken_edge_p
= find_edge (gimple_bb (stmt
),
6192 label_to_block (CASE_LABEL (val
)));
6194 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
6196 fprintf (dump_file
, " will take edge to ");
6197 print_generic_stmt (dump_file
, CASE_LABEL (val
), 0);
6200 return SSA_PROP_INTERESTING
;
6204 /* Evaluate statement STMT. If the statement produces a useful range,
6205 return SSA_PROP_INTERESTING and record the SSA name with the
6206 interesting range into *OUTPUT_P.
6208 If STMT is a conditional branch and we can determine its truth
6209 value, the taken edge is recorded in *TAKEN_EDGE_P.
6211 If STMT produces a varying value, return SSA_PROP_VARYING. */
6213 static enum ssa_prop_result
6214 vrp_visit_stmt (gimple stmt
, edge
*taken_edge_p
, tree
*output_p
)
6219 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
6221 fprintf (dump_file
, "\nVisiting statement:\n");
6222 print_gimple_stmt (dump_file
, stmt
, 0, dump_flags
);
6223 fprintf (dump_file
, "\n");
6226 if (!stmt_interesting_for_vrp (stmt
))
6227 gcc_assert (stmt_ends_bb_p (stmt
));
6228 else if (is_gimple_assign (stmt
) || is_gimple_call (stmt
))
6230 /* In general, assignments with virtual operands are not useful
6231 for deriving ranges, with the obvious exception of calls to
6232 builtin functions. */
6234 if ((is_gimple_call (stmt
)
6235 && gimple_call_fndecl (stmt
) != NULL_TREE
6236 && DECL_IS_BUILTIN (gimple_call_fndecl (stmt
)))
6237 || !gimple_vuse (stmt
))
6238 return vrp_visit_assignment_or_call (stmt
, output_p
);
6240 else if (gimple_code (stmt
) == GIMPLE_COND
)
6241 return vrp_visit_cond_stmt (stmt
, taken_edge_p
);
6242 else if (gimple_code (stmt
) == GIMPLE_SWITCH
)
6243 return vrp_visit_switch_stmt (stmt
, taken_edge_p
);
6245 /* All other statements produce nothing of interest for VRP, so mark
6246 their outputs varying and prevent further simulation. */
6247 FOR_EACH_SSA_TREE_OPERAND (def
, stmt
, iter
, SSA_OP_DEF
)
6248 set_value_range_to_varying (get_value_range (def
));
6250 return SSA_PROP_VARYING
;
6254 /* Meet operation for value ranges. Given two value ranges VR0 and
6255 VR1, store in VR0 a range that contains both VR0 and VR1. This
6256 may not be the smallest possible such range. */
6259 vrp_meet (value_range_t
*vr0
, value_range_t
*vr1
)
6261 if (vr0
->type
== VR_UNDEFINED
)
6263 copy_value_range (vr0
, vr1
);
6267 if (vr1
->type
== VR_UNDEFINED
)
6269 /* Nothing to do. VR0 already has the resulting range. */
6273 if (vr0
->type
== VR_VARYING
)
6275 /* Nothing to do. VR0 already has the resulting range. */
6279 if (vr1
->type
== VR_VARYING
)
6281 set_value_range_to_varying (vr0
);
6285 if (vr0
->type
== VR_RANGE
&& vr1
->type
== VR_RANGE
)
6290 /* Compute the convex hull of the ranges. The lower limit of
6291 the new range is the minimum of the two ranges. If they
6292 cannot be compared, then give up. */
6293 cmp
= compare_values (vr0
->min
, vr1
->min
);
6294 if (cmp
== 0 || cmp
== 1)
6301 /* Similarly, the upper limit of the new range is the maximum
6302 of the two ranges. If they cannot be compared, then
6304 cmp
= compare_values (vr0
->max
, vr1
->max
);
6305 if (cmp
== 0 || cmp
== -1)
6312 /* Check for useless ranges. */
6313 if (INTEGRAL_TYPE_P (TREE_TYPE (min
))
6314 && ((vrp_val_is_min (min
) || is_overflow_infinity (min
))
6315 && (vrp_val_is_max (max
) || is_overflow_infinity (max
))))
6318 /* The resulting set of equivalences is the intersection of
6320 if (vr0
->equiv
&& vr1
->equiv
&& vr0
->equiv
!= vr1
->equiv
)
6321 bitmap_and_into (vr0
->equiv
, vr1
->equiv
);
6322 else if (vr0
->equiv
&& !vr1
->equiv
)
6323 bitmap_clear (vr0
->equiv
);
6325 set_value_range (vr0
, vr0
->type
, min
, max
, vr0
->equiv
);
6327 else if (vr0
->type
== VR_ANTI_RANGE
&& vr1
->type
== VR_ANTI_RANGE
)
6329 /* Two anti-ranges meet only if their complements intersect.
6330 Only handle the case of identical ranges. */
6331 if (compare_values (vr0
->min
, vr1
->min
) == 0
6332 && compare_values (vr0
->max
, vr1
->max
) == 0
6333 && compare_values (vr0
->min
, vr0
->max
) == 0)
6335 /* The resulting set of equivalences is the intersection of
6337 if (vr0
->equiv
&& vr1
->equiv
&& vr0
->equiv
!= vr1
->equiv
)
6338 bitmap_and_into (vr0
->equiv
, vr1
->equiv
);
6339 else if (vr0
->equiv
&& !vr1
->equiv
)
6340 bitmap_clear (vr0
->equiv
);
6345 else if (vr0
->type
== VR_ANTI_RANGE
|| vr1
->type
== VR_ANTI_RANGE
)
6347 /* For a numeric range [VAL1, VAL2] and an anti-range ~[VAL3, VAL4],
6348 only handle the case where the ranges have an empty intersection.
6349 The result of the meet operation is the anti-range. */
6350 if (!symbolic_range_p (vr0
)
6351 && !symbolic_range_p (vr1
)
6352 && !value_ranges_intersect_p (vr0
, vr1
))
6354 /* Copy most of VR1 into VR0. Don't copy VR1's equivalence
6355 set. We need to compute the intersection of the two
6356 equivalence sets. */
6357 if (vr1
->type
== VR_ANTI_RANGE
)
6358 set_value_range (vr0
, vr1
->type
, vr1
->min
, vr1
->max
, vr0
->equiv
);
6360 /* The resulting set of equivalences is the intersection of
6362 if (vr0
->equiv
&& vr1
->equiv
&& vr0
->equiv
!= vr1
->equiv
)
6363 bitmap_and_into (vr0
->equiv
, vr1
->equiv
);
6364 else if (vr0
->equiv
&& !vr1
->equiv
)
6365 bitmap_clear (vr0
->equiv
);
6376 /* Failed to find an efficient meet. Before giving up and setting
6377 the result to VARYING, see if we can at least derive a useful
6378 anti-range. FIXME, all this nonsense about distinguishing
6379 anti-ranges from ranges is necessary because of the odd
6380 semantics of range_includes_zero_p and friends. */
6381 if (!symbolic_range_p (vr0
)
6382 && ((vr0
->type
== VR_RANGE
&& !range_includes_zero_p (vr0
))
6383 || (vr0
->type
== VR_ANTI_RANGE
&& range_includes_zero_p (vr0
)))
6384 && !symbolic_range_p (vr1
)
6385 && ((vr1
->type
== VR_RANGE
&& !range_includes_zero_p (vr1
))
6386 || (vr1
->type
== VR_ANTI_RANGE
&& range_includes_zero_p (vr1
))))
6388 set_value_range_to_nonnull (vr0
, TREE_TYPE (vr0
->min
));
6390 /* Since this meet operation did not result from the meeting of
6391 two equivalent names, VR0 cannot have any equivalences. */
6393 bitmap_clear (vr0
->equiv
);
6396 set_value_range_to_varying (vr0
);
6400 /* Visit all arguments for PHI node PHI that flow through executable
6401 edges. If a valid value range can be derived from all the incoming
6402 value ranges, set a new range for the LHS of PHI. */
6404 static enum ssa_prop_result
6405 vrp_visit_phi_node (gimple phi
)
6408 tree lhs
= PHI_RESULT (phi
);
6409 value_range_t
*lhs_vr
= get_value_range (lhs
);
6410 value_range_t vr_result
= { VR_UNDEFINED
, NULL_TREE
, NULL_TREE
, NULL
};
6411 int edges
, old_edges
;
6414 copy_value_range (&vr_result
, lhs_vr
);
6416 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
6418 fprintf (dump_file
, "\nVisiting PHI node: ");
6419 print_gimple_stmt (dump_file
, phi
, 0, dump_flags
);
6423 for (i
= 0; i
< gimple_phi_num_args (phi
); i
++)
6425 edge e
= gimple_phi_arg_edge (phi
, i
);
6427 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
6430 "\n Argument #%d (%d -> %d %sexecutable)\n",
6431 (int) i
, e
->src
->index
, e
->dest
->index
,
6432 (e
->flags
& EDGE_EXECUTABLE
) ? "" : "not ");
6435 if (e
->flags
& EDGE_EXECUTABLE
)
6437 tree arg
= PHI_ARG_DEF (phi
, i
);
6438 value_range_t vr_arg
;
6442 if (TREE_CODE (arg
) == SSA_NAME
)
6444 vr_arg
= *(get_value_range (arg
));
6448 if (is_overflow_infinity (arg
))
6450 arg
= copy_node (arg
);
6451 TREE_OVERFLOW (arg
) = 0;
6454 vr_arg
.type
= VR_RANGE
;
6457 vr_arg
.equiv
= NULL
;
6460 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
6462 fprintf (dump_file
, "\t");
6463 print_generic_expr (dump_file
, arg
, dump_flags
);
6464 fprintf (dump_file
, "\n\tValue: ");
6465 dump_value_range (dump_file
, &vr_arg
);
6466 fprintf (dump_file
, "\n");
6469 vrp_meet (&vr_result
, &vr_arg
);
6471 if (vr_result
.type
== VR_VARYING
)
6476 /* If this is a loop PHI node SCEV may known more about its
6479 && (l
= loop_containing_stmt (phi
))
6480 && l
->header
== gimple_bb (phi
))
6481 adjust_range_with_scev (&vr_result
, l
, phi
, lhs
);
6483 if (vr_result
.type
== VR_VARYING
)
6486 old_edges
= vr_phi_edge_counts
[SSA_NAME_VERSION (lhs
)];
6487 vr_phi_edge_counts
[SSA_NAME_VERSION (lhs
)] = edges
;
6489 /* To prevent infinite iterations in the algorithm, derive ranges
6490 when the new value is slightly bigger or smaller than the
6491 previous one. We don't do this if we have seen a new executable
6492 edge; this helps us avoid an overflow infinity for conditionals
6493 which are not in a loop. */
6494 if (lhs_vr
->type
== VR_RANGE
&& vr_result
.type
== VR_RANGE
6495 && edges
<= old_edges
)
6497 if (!POINTER_TYPE_P (TREE_TYPE (lhs
)))
6499 int cmp_min
= compare_values (lhs_vr
->min
, vr_result
.min
);
6500 int cmp_max
= compare_values (lhs_vr
->max
, vr_result
.max
);
6502 /* If the new minimum is smaller or larger than the previous
6503 one, go all the way to -INF. In the first case, to avoid
6504 iterating millions of times to reach -INF, and in the
6505 other case to avoid infinite bouncing between different
6507 if (cmp_min
> 0 || cmp_min
< 0)
6509 /* If we will end up with a (-INF, +INF) range, set it to
6510 VARYING. Same if the previous max value was invalid for
6511 the type and we'd end up with vr_result.min > vr_result.max. */
6512 if (vrp_val_is_max (vr_result
.max
)
6513 || compare_values (TYPE_MIN_VALUE (TREE_TYPE (vr_result
.min
)),
6517 if (!needs_overflow_infinity (TREE_TYPE (vr_result
.min
))
6518 || !vrp_var_may_overflow (lhs
, phi
))
6519 vr_result
.min
= TYPE_MIN_VALUE (TREE_TYPE (vr_result
.min
));
6520 else if (supports_overflow_infinity (TREE_TYPE (vr_result
.min
)))
6522 negative_overflow_infinity (TREE_TYPE (vr_result
.min
));
6527 /* Similarly, if the new maximum is smaller or larger than
6528 the previous one, go all the way to +INF. */
6529 if (cmp_max
< 0 || cmp_max
> 0)
6531 /* If we will end up with a (-INF, +INF) range, set it to
6532 VARYING. Same if the previous min value was invalid for
6533 the type and we'd end up with vr_result.max < vr_result.min. */
6534 if (vrp_val_is_min (vr_result
.min
)
6535 || compare_values (TYPE_MAX_VALUE (TREE_TYPE (vr_result
.max
)),
6539 if (!needs_overflow_infinity (TREE_TYPE (vr_result
.max
))
6540 || !vrp_var_may_overflow (lhs
, phi
))
6541 vr_result
.max
= TYPE_MAX_VALUE (TREE_TYPE (vr_result
.max
));
6542 else if (supports_overflow_infinity (TREE_TYPE (vr_result
.max
)))
6544 positive_overflow_infinity (TREE_TYPE (vr_result
.max
));
6551 /* If the new range is different than the previous value, keep
6553 if (update_value_range (lhs
, &vr_result
))
6555 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
6557 fprintf (dump_file
, "Found new range for ");
6558 print_generic_expr (dump_file
, lhs
, 0);
6559 fprintf (dump_file
, ": ");
6560 dump_value_range (dump_file
, &vr_result
);
6561 fprintf (dump_file
, "\n\n");
6564 return SSA_PROP_INTERESTING
;
6567 /* Nothing changed, don't add outgoing edges. */
6568 return SSA_PROP_NOT_INTERESTING
;
6570 /* No match found. Set the LHS to VARYING. */
6572 set_value_range_to_varying (lhs_vr
);
6573 return SSA_PROP_VARYING
;
6576 /* Simplify boolean operations if the source is known
6577 to be already a boolean. */
6579 simplify_truth_ops_using_ranges (gimple_stmt_iterator
*gsi
, gimple stmt
)
6581 enum tree_code rhs_code
= gimple_assign_rhs_code (stmt
);
6586 bool need_conversion
;
6588 op0
= gimple_assign_rhs1 (stmt
);
6589 if (TYPE_PRECISION (TREE_TYPE (op0
)) != 1)
6591 if (TREE_CODE (op0
) != SSA_NAME
)
6593 vr
= get_value_range (op0
);
6595 val
= compare_range_with_value (GE_EXPR
, vr
, integer_zero_node
, &sop
);
6596 if (!val
|| !integer_onep (val
))
6599 val
= compare_range_with_value (LE_EXPR
, vr
, integer_one_node
, &sop
);
6600 if (!val
|| !integer_onep (val
))
6604 if (rhs_code
== TRUTH_NOT_EXPR
)
6607 op1
= build_int_cst (TREE_TYPE (op0
), 1);
6611 op1
= gimple_assign_rhs2 (stmt
);
6613 /* Reduce number of cases to handle. */
6614 if (is_gimple_min_invariant (op1
))
6616 /* Exclude anything that should have been already folded. */
6617 if (rhs_code
!= EQ_EXPR
6618 && rhs_code
!= NE_EXPR
6619 && rhs_code
!= TRUTH_XOR_EXPR
)
6622 if (!integer_zerop (op1
)
6623 && !integer_onep (op1
)
6624 && !integer_all_onesp (op1
))
6627 /* Limit the number of cases we have to consider. */
6628 if (rhs_code
== EQ_EXPR
)
6631 op1
= fold_unary (TRUTH_NOT_EXPR
, TREE_TYPE (op1
), op1
);
6636 /* Punt on A == B as there is no BIT_XNOR_EXPR. */
6637 if (rhs_code
== EQ_EXPR
)
6640 if (TYPE_PRECISION (TREE_TYPE (op1
)) != 1)
6642 vr
= get_value_range (op1
);
6643 val
= compare_range_with_value (GE_EXPR
, vr
, integer_zero_node
, &sop
);
6644 if (!val
|| !integer_onep (val
))
6647 val
= compare_range_with_value (LE_EXPR
, vr
, integer_one_node
, &sop
);
6648 if (!val
|| !integer_onep (val
))
6654 if (sop
&& issue_strict_overflow_warning (WARN_STRICT_OVERFLOW_MISC
))
6656 location_t location
;
6658 if (!gimple_has_location (stmt
))
6659 location
= input_location
;
6661 location
= gimple_location (stmt
);
6663 if (rhs_code
== TRUTH_AND_EXPR
|| rhs_code
== TRUTH_OR_EXPR
)
6664 warning_at (location
, OPT_Wstrict_overflow
,
6665 _("assuming signed overflow does not occur when "
6666 "simplifying && or || to & or |"));
6668 warning_at (location
, OPT_Wstrict_overflow
,
6669 _("assuming signed overflow does not occur when "
6670 "simplifying ==, != or ! to identity or ^"));
6674 !useless_type_conversion_p (TREE_TYPE (gimple_assign_lhs (stmt
)),
6677 /* Make sure to not sign-extend -1 as a boolean value. */
6679 && !TYPE_UNSIGNED (TREE_TYPE (op0
))
6680 && TYPE_PRECISION (TREE_TYPE (op0
)) == 1)
6685 case TRUTH_AND_EXPR
:
6686 rhs_code
= BIT_AND_EXPR
;
6689 rhs_code
= BIT_IOR_EXPR
;
6691 case TRUTH_XOR_EXPR
:
6693 if (integer_zerop (op1
))
6695 gimple_assign_set_rhs_with_ops (gsi
,
6696 need_conversion
? NOP_EXPR
: SSA_NAME
,
6698 update_stmt (gsi_stmt (*gsi
));
6702 rhs_code
= BIT_XOR_EXPR
;
6708 if (need_conversion
)
6711 gimple_assign_set_rhs_with_ops (gsi
, rhs_code
, op0
, op1
);
6712 update_stmt (gsi_stmt (*gsi
));
6716 /* Simplify a division or modulo operator to a right shift or
6717 bitwise and if the first operand is unsigned or is greater
6718 than zero and the second operand is an exact power of two. */
6721 simplify_div_or_mod_using_ranges (gimple stmt
)
6723 enum tree_code rhs_code
= gimple_assign_rhs_code (stmt
);
6725 tree op0
= gimple_assign_rhs1 (stmt
);
6726 tree op1
= gimple_assign_rhs2 (stmt
);
6727 value_range_t
*vr
= get_value_range (gimple_assign_rhs1 (stmt
));
6729 if (TYPE_UNSIGNED (TREE_TYPE (op0
)))
6731 val
= integer_one_node
;
6737 val
= compare_range_with_value (GE_EXPR
, vr
, integer_zero_node
, &sop
);
6741 && integer_onep (val
)
6742 && issue_strict_overflow_warning (WARN_STRICT_OVERFLOW_MISC
))
6744 location_t location
;
6746 if (!gimple_has_location (stmt
))
6747 location
= input_location
;
6749 location
= gimple_location (stmt
);
6750 warning_at (location
, OPT_Wstrict_overflow
,
6751 "assuming signed overflow does not occur when "
6752 "simplifying %</%> or %<%%%> to %<>>%> or %<&%>");
6756 if (val
&& integer_onep (val
))
6760 if (rhs_code
== TRUNC_DIV_EXPR
)
6762 t
= build_int_cst (NULL_TREE
, tree_log2 (op1
));
6763 gimple_assign_set_rhs_code (stmt
, RSHIFT_EXPR
);
6764 gimple_assign_set_rhs1 (stmt
, op0
);
6765 gimple_assign_set_rhs2 (stmt
, t
);
6769 t
= build_int_cst (TREE_TYPE (op1
), 1);
6770 t
= int_const_binop (MINUS_EXPR
, op1
, t
, 0);
6771 t
= fold_convert (TREE_TYPE (op0
), t
);
6773 gimple_assign_set_rhs_code (stmt
, BIT_AND_EXPR
);
6774 gimple_assign_set_rhs1 (stmt
, op0
);
6775 gimple_assign_set_rhs2 (stmt
, t
);
6785 /* If the operand to an ABS_EXPR is >= 0, then eliminate the
6786 ABS_EXPR. If the operand is <= 0, then simplify the
6787 ABS_EXPR into a NEGATE_EXPR. */
6790 simplify_abs_using_ranges (gimple stmt
)
6793 tree op
= gimple_assign_rhs1 (stmt
);
6794 tree type
= TREE_TYPE (op
);
6795 value_range_t
*vr
= get_value_range (op
);
6797 if (TYPE_UNSIGNED (type
))
6799 val
= integer_zero_node
;
6805 val
= compare_range_with_value (LE_EXPR
, vr
, integer_zero_node
, &sop
);
6809 val
= compare_range_with_value (GE_EXPR
, vr
, integer_zero_node
,
6814 if (integer_zerop (val
))
6815 val
= integer_one_node
;
6816 else if (integer_onep (val
))
6817 val
= integer_zero_node
;
6822 && (integer_onep (val
) || integer_zerop (val
)))
6824 if (sop
&& issue_strict_overflow_warning (WARN_STRICT_OVERFLOW_MISC
))
6826 location_t location
;
6828 if (!gimple_has_location (stmt
))
6829 location
= input_location
;
6831 location
= gimple_location (stmt
);
6832 warning_at (location
, OPT_Wstrict_overflow
,
6833 "assuming signed overflow does not occur when "
6834 "simplifying %<abs (X)%> to %<X%> or %<-X%>");
6837 gimple_assign_set_rhs1 (stmt
, op
);
6838 if (integer_onep (val
))
6839 gimple_assign_set_rhs_code (stmt
, NEGATE_EXPR
);
6841 gimple_assign_set_rhs_code (stmt
, SSA_NAME
);
6850 /* We are comparing trees OP0 and OP1 using COND_CODE. OP0 has
6851 a known value range VR.
6853 If there is one and only one value which will satisfy the
6854 conditional, then return that value. Else return NULL. */
6857 test_for_singularity (enum tree_code cond_code
, tree op0
,
6858 tree op1
, value_range_t
*vr
)
6863 /* Extract minimum/maximum values which satisfy the
6864 the conditional as it was written. */
6865 if (cond_code
== LE_EXPR
|| cond_code
== LT_EXPR
)
6867 /* This should not be negative infinity; there is no overflow
6869 min
= TYPE_MIN_VALUE (TREE_TYPE (op0
));
6872 if (cond_code
== LT_EXPR
&& !is_overflow_infinity (max
))
6874 tree one
= build_int_cst (TREE_TYPE (op0
), 1);
6875 max
= fold_build2 (MINUS_EXPR
, TREE_TYPE (op0
), max
, one
);
6877 TREE_NO_WARNING (max
) = 1;
6880 else if (cond_code
== GE_EXPR
|| cond_code
== GT_EXPR
)
6882 /* This should not be positive infinity; there is no overflow
6884 max
= TYPE_MAX_VALUE (TREE_TYPE (op0
));
6887 if (cond_code
== GT_EXPR
&& !is_overflow_infinity (min
))
6889 tree one
= build_int_cst (TREE_TYPE (op0
), 1);
6890 min
= fold_build2 (PLUS_EXPR
, TREE_TYPE (op0
), min
, one
);
6892 TREE_NO_WARNING (min
) = 1;
6896 /* Now refine the minimum and maximum values using any
6897 value range information we have for op0. */
6900 if (compare_values (vr
->min
, min
) == 1)
6902 if (compare_values (vr
->max
, max
) == -1)
6905 /* If the new min/max values have converged to a single value,
6906 then there is only one value which can satisfy the condition,
6907 return that value. */
6908 if (operand_equal_p (min
, max
, 0) && is_gimple_min_invariant (min
))
6914 /* Simplify a conditional using a relational operator to an equality
6915 test if the range information indicates only one value can satisfy
6916 the original conditional. */
6919 simplify_cond_using_ranges (gimple stmt
)
6921 tree op0
= gimple_cond_lhs (stmt
);
6922 tree op1
= gimple_cond_rhs (stmt
);
6923 enum tree_code cond_code
= gimple_cond_code (stmt
);
6925 if (cond_code
!= NE_EXPR
6926 && cond_code
!= EQ_EXPR
6927 && TREE_CODE (op0
) == SSA_NAME
6928 && INTEGRAL_TYPE_P (TREE_TYPE (op0
))
6929 && is_gimple_min_invariant (op1
))
6931 value_range_t
*vr
= get_value_range (op0
);
6933 /* If we have range information for OP0, then we might be
6934 able to simplify this conditional. */
6935 if (vr
->type
== VR_RANGE
)
6937 tree new_tree
= test_for_singularity (cond_code
, op0
, op1
, vr
);
6943 fprintf (dump_file
, "Simplified relational ");
6944 print_gimple_stmt (dump_file
, stmt
, 0, 0);
6945 fprintf (dump_file
, " into ");
6948 gimple_cond_set_code (stmt
, EQ_EXPR
);
6949 gimple_cond_set_lhs (stmt
, op0
);
6950 gimple_cond_set_rhs (stmt
, new_tree
);
6956 print_gimple_stmt (dump_file
, stmt
, 0, 0);
6957 fprintf (dump_file
, "\n");
6963 /* Try again after inverting the condition. We only deal
6964 with integral types here, so no need to worry about
6965 issues with inverting FP comparisons. */
6966 cond_code
= invert_tree_comparison (cond_code
, false);
6967 new_tree
= test_for_singularity (cond_code
, op0
, op1
, vr
);
6973 fprintf (dump_file
, "Simplified relational ");
6974 print_gimple_stmt (dump_file
, stmt
, 0, 0);
6975 fprintf (dump_file
, " into ");
6978 gimple_cond_set_code (stmt
, NE_EXPR
);
6979 gimple_cond_set_lhs (stmt
, op0
);
6980 gimple_cond_set_rhs (stmt
, new_tree
);
6986 print_gimple_stmt (dump_file
, stmt
, 0, 0);
6987 fprintf (dump_file
, "\n");
6998 /* Simplify a switch statement using the value range of the switch
7002 simplify_switch_using_ranges (gimple stmt
)
7004 tree op
= gimple_switch_index (stmt
);
7009 size_t i
= 0, j
= 0, n
, n2
;
7013 if (TREE_CODE (op
) == SSA_NAME
)
7015 vr
= get_value_range (op
);
7017 /* We can only handle integer ranges. */
7018 if (vr
->type
!= VR_RANGE
7019 || symbolic_range_p (vr
))
7022 /* Find case label for min/max of the value range. */
7023 take_default
= !find_case_label_range (stmt
, vr
->min
, vr
->max
, &i
, &j
);
7025 else if (TREE_CODE (op
) == INTEGER_CST
)
7027 take_default
= !find_case_label_index (stmt
, 1, op
, &i
);
7041 n
= gimple_switch_num_labels (stmt
);
7043 /* Bail out if this is just all edges taken. */
7049 /* Build a new vector of taken case labels. */
7050 vec2
= make_tree_vec (j
- i
+ 1 + (int)take_default
);
7053 /* Add the default edge, if necessary. */
7055 TREE_VEC_ELT (vec2
, n2
++) = gimple_switch_default_label (stmt
);
7057 for (; i
<= j
; ++i
, ++n2
)
7058 TREE_VEC_ELT (vec2
, n2
) = gimple_switch_label (stmt
, i
);
7060 /* Mark needed edges. */
7061 for (i
= 0; i
< n2
; ++i
)
7063 e
= find_edge (gimple_bb (stmt
),
7064 label_to_block (CASE_LABEL (TREE_VEC_ELT (vec2
, i
))));
7065 e
->aux
= (void *)-1;
7068 /* Queue not needed edges for later removal. */
7069 FOR_EACH_EDGE (e
, ei
, gimple_bb (stmt
)->succs
)
7071 if (e
->aux
== (void *)-1)
7077 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
7079 fprintf (dump_file
, "removing unreachable case label\n");
7081 VEC_safe_push (edge
, heap
, to_remove_edges
, e
);
7082 e
->flags
&= ~EDGE_EXECUTABLE
;
7085 /* And queue an update for the stmt. */
7088 VEC_safe_push (switch_update
, heap
, to_update_switch_stmts
, &su
);
7092 /* Simplify STMT using ranges if possible. */
7095 simplify_stmt_using_ranges (gimple_stmt_iterator
*gsi
)
7097 gimple stmt
= gsi_stmt (*gsi
);
7098 if (is_gimple_assign (stmt
))
7100 enum tree_code rhs_code
= gimple_assign_rhs_code (stmt
);
7106 case TRUTH_NOT_EXPR
:
7107 case TRUTH_AND_EXPR
:
7109 case TRUTH_XOR_EXPR
:
7110 /* Transform EQ_EXPR, NE_EXPR, TRUTH_NOT_EXPR into BIT_XOR_EXPR
7111 or identity if the RHS is zero or one, and the LHS are known
7112 to be boolean values. Transform all TRUTH_*_EXPR into
7113 BIT_*_EXPR if both arguments are known to be boolean values. */
7114 if (INTEGRAL_TYPE_P (TREE_TYPE (gimple_assign_rhs1 (stmt
))))
7115 return simplify_truth_ops_using_ranges (gsi
, stmt
);
7118 /* Transform TRUNC_DIV_EXPR and TRUNC_MOD_EXPR into RSHIFT_EXPR
7119 and BIT_AND_EXPR respectively if the first operand is greater
7120 than zero and the second operand is an exact power of two. */
7121 case TRUNC_DIV_EXPR
:
7122 case TRUNC_MOD_EXPR
:
7123 if (INTEGRAL_TYPE_P (TREE_TYPE (gimple_assign_rhs1 (stmt
)))
7124 && integer_pow2p (gimple_assign_rhs2 (stmt
)))
7125 return simplify_div_or_mod_using_ranges (stmt
);
7128 /* Transform ABS (X) into X or -X as appropriate. */
7130 if (TREE_CODE (gimple_assign_rhs1 (stmt
)) == SSA_NAME
7131 && INTEGRAL_TYPE_P (TREE_TYPE (gimple_assign_rhs1 (stmt
))))
7132 return simplify_abs_using_ranges (stmt
);
7139 else if (gimple_code (stmt
) == GIMPLE_COND
)
7140 return simplify_cond_using_ranges (stmt
);
7141 else if (gimple_code (stmt
) == GIMPLE_SWITCH
)
7142 return simplify_switch_using_ranges (stmt
);
7147 /* If the statement pointed by SI has a predicate whose value can be
7148 computed using the value range information computed by VRP, compute
7149 its value and return true. Otherwise, return false. */
7152 fold_predicate_in (gimple_stmt_iterator
*si
)
7154 bool assignment_p
= false;
7156 gimple stmt
= gsi_stmt (*si
);
7158 if (is_gimple_assign (stmt
)
7159 && TREE_CODE_CLASS (gimple_assign_rhs_code (stmt
)) == tcc_comparison
)
7161 assignment_p
= true;
7162 val
= vrp_evaluate_conditional (gimple_assign_rhs_code (stmt
),
7163 gimple_assign_rhs1 (stmt
),
7164 gimple_assign_rhs2 (stmt
),
7167 else if (gimple_code (stmt
) == GIMPLE_COND
)
7168 val
= vrp_evaluate_conditional (gimple_cond_code (stmt
),
7169 gimple_cond_lhs (stmt
),
7170 gimple_cond_rhs (stmt
),
7178 val
= fold_convert (gimple_expr_type (stmt
), val
);
7182 fprintf (dump_file
, "Folding predicate ");
7183 print_gimple_expr (dump_file
, stmt
, 0, 0);
7184 fprintf (dump_file
, " to ");
7185 print_generic_expr (dump_file
, val
, 0);
7186 fprintf (dump_file
, "\n");
7189 if (is_gimple_assign (stmt
))
7190 gimple_assign_set_rhs_from_tree (si
, val
);
7193 gcc_assert (gimple_code (stmt
) == GIMPLE_COND
);
7194 if (integer_zerop (val
))
7195 gimple_cond_make_false (stmt
);
7196 else if (integer_onep (val
))
7197 gimple_cond_make_true (stmt
);
7208 /* Callback for substitute_and_fold folding the stmt at *SI. */
7211 vrp_fold_stmt (gimple_stmt_iterator
*si
)
7213 if (fold_predicate_in (si
))
7216 return simplify_stmt_using_ranges (si
);
7219 /* Stack of dest,src equivalency pairs that need to be restored after
7220 each attempt to thread a block's incoming edge to an outgoing edge.
7222 A NULL entry is used to mark the end of pairs which need to be
7224 static VEC(tree
,heap
) *stack
;
7226 /* A trivial wrapper so that we can present the generic jump threading
7227 code with a simple API for simplifying statements. STMT is the
7228 statement we want to simplify, WITHIN_STMT provides the location
7229 for any overflow warnings. */
7232 simplify_stmt_for_jump_threading (gimple stmt
, gimple within_stmt
)
7234 /* We only use VRP information to simplify conditionals. This is
7235 overly conservative, but it's unclear if doing more would be
7236 worth the compile time cost. */
7237 if (gimple_code (stmt
) != GIMPLE_COND
)
7240 return vrp_evaluate_conditional (gimple_cond_code (stmt
),
7241 gimple_cond_lhs (stmt
),
7242 gimple_cond_rhs (stmt
), within_stmt
);
7245 /* Blocks which have more than one predecessor and more than
7246 one successor present jump threading opportunities, i.e.,
7247 when the block is reached from a specific predecessor, we
7248 may be able to determine which of the outgoing edges will
7249 be traversed. When this optimization applies, we are able
7250 to avoid conditionals at runtime and we may expose secondary
7251 optimization opportunities.
7253 This routine is effectively a driver for the generic jump
7254 threading code. It basically just presents the generic code
7255 with edges that may be suitable for jump threading.
7257 Unlike DOM, we do not iterate VRP if jump threading was successful.
7258 While iterating may expose new opportunities for VRP, it is expected
7259 those opportunities would be very limited and the compile time cost
7260 to expose those opportunities would be significant.
7262 As jump threading opportunities are discovered, they are registered
7263 for later realization. */
7266 identify_jump_threads (void)
7273 /* Ugh. When substituting values earlier in this pass we can
7274 wipe the dominance information. So rebuild the dominator
7275 information as we need it within the jump threading code. */
7276 calculate_dominance_info (CDI_DOMINATORS
);
7278 /* We do not allow VRP information to be used for jump threading
7279 across a back edge in the CFG. Otherwise it becomes too
7280 difficult to avoid eliminating loop exit tests. Of course
7281 EDGE_DFS_BACK is not accurate at this time so we have to
7283 mark_dfs_back_edges ();
7285 /* Do not thread across edges we are about to remove. Just marking
7286 them as EDGE_DFS_BACK will do. */
7287 for (i
= 0; VEC_iterate (edge
, to_remove_edges
, i
, e
); ++i
)
7288 e
->flags
|= EDGE_DFS_BACK
;
7290 /* Allocate our unwinder stack to unwind any temporary equivalences
7291 that might be recorded. */
7292 stack
= VEC_alloc (tree
, heap
, 20);
7294 /* To avoid lots of silly node creation, we create a single
7295 conditional and just modify it in-place when attempting to
7297 dummy
= gimple_build_cond (EQ_EXPR
,
7298 integer_zero_node
, integer_zero_node
,
7301 /* Walk through all the blocks finding those which present a
7302 potential jump threading opportunity. We could set this up
7303 as a dominator walker and record data during the walk, but
7304 I doubt it's worth the effort for the classes of jump
7305 threading opportunities we are trying to identify at this
7306 point in compilation. */
7311 /* If the generic jump threading code does not find this block
7312 interesting, then there is nothing to do. */
7313 if (! potentially_threadable_block (bb
))
7316 /* We only care about blocks ending in a COND_EXPR. While there
7317 may be some value in handling SWITCH_EXPR here, I doubt it's
7318 terribly important. */
7319 last
= gsi_stmt (gsi_last_bb (bb
));
7320 if (gimple_code (last
) != GIMPLE_COND
)
7323 /* We're basically looking for any kind of conditional with
7324 integral type arguments. */
7325 if (TREE_CODE (gimple_cond_lhs (last
)) == SSA_NAME
7326 && INTEGRAL_TYPE_P (TREE_TYPE (gimple_cond_lhs (last
)))
7327 && (TREE_CODE (gimple_cond_rhs (last
)) == SSA_NAME
7328 || is_gimple_min_invariant (gimple_cond_rhs (last
)))
7329 && INTEGRAL_TYPE_P (TREE_TYPE (gimple_cond_rhs (last
))))
7333 /* We've got a block with multiple predecessors and multiple
7334 successors which also ends in a suitable conditional. For
7335 each predecessor, see if we can thread it to a specific
7337 FOR_EACH_EDGE (e
, ei
, bb
->preds
)
7339 /* Do not thread across back edges or abnormal edges
7341 if (e
->flags
& (EDGE_DFS_BACK
| EDGE_COMPLEX
))
7344 thread_across_edge (dummy
, e
, true, &stack
,
7345 simplify_stmt_for_jump_threading
);
7350 /* We do not actually update the CFG or SSA graphs at this point as
7351 ASSERT_EXPRs are still in the IL and cfg cleanup code does not yet
7352 handle ASSERT_EXPRs gracefully. */
7355 /* We identified all the jump threading opportunities earlier, but could
7356 not transform the CFG at that time. This routine transforms the
7357 CFG and arranges for the dominator tree to be rebuilt if necessary.
7359 Note the SSA graph update will occur during the normal TODO
7360 processing by the pass manager. */
7362 finalize_jump_threads (void)
7364 thread_through_all_blocks (false);
7365 VEC_free (tree
, heap
, stack
);
7369 /* Traverse all the blocks folding conditionals with known ranges. */
7375 prop_value_t
*single_val_range
;
7376 bool do_value_subst_p
;
7377 unsigned num
= num_ssa_names
;
7381 fprintf (dump_file
, "\nValue ranges after VRP:\n\n");
7382 dump_all_value_ranges (dump_file
);
7383 fprintf (dump_file
, "\n");
7386 /* We may have ended with ranges that have exactly one value. Those
7387 values can be substituted as any other const propagated
7388 value using substitute_and_fold. */
7389 single_val_range
= XCNEWVEC (prop_value_t
, num
);
7391 do_value_subst_p
= false;
7392 for (i
= 0; i
< num
; i
++)
7394 && vr_value
[i
]->type
== VR_RANGE
7395 && vr_value
[i
]->min
== vr_value
[i
]->max
7396 && is_gimple_min_invariant (vr_value
[i
]->min
))
7398 single_val_range
[i
].value
= vr_value
[i
]->min
;
7399 do_value_subst_p
= true;
7402 if (!do_value_subst_p
)
7404 /* We found no single-valued ranges, don't waste time trying to
7405 do single value substitution in substitute_and_fold. */
7406 free (single_val_range
);
7407 single_val_range
= NULL
;
7410 substitute_and_fold (single_val_range
, vrp_fold_stmt
, false);
7412 if (warn_array_bounds
)
7413 check_all_array_refs ();
7415 /* We must identify jump threading opportunities before we release
7416 the datastructures built by VRP. */
7417 identify_jump_threads ();
7419 /* Free allocated memory. */
7420 for (i
= 0; i
< num
; i
++)
7423 BITMAP_FREE (vr_value
[i
]->equiv
);
7427 free (single_val_range
);
7429 free (vr_phi_edge_counts
);
7431 /* So that we can distinguish between VRP data being available
7432 and not available. */
7434 vr_phi_edge_counts
= NULL
;
7438 /* Main entry point to VRP (Value Range Propagation). This pass is
7439 loosely based on J. R. C. Patterson, ``Accurate Static Branch
7440 Prediction by Value Range Propagation,'' in SIGPLAN Conference on
7441 Programming Language Design and Implementation, pp. 67-78, 1995.
7442 Also available at http://citeseer.ist.psu.edu/patterson95accurate.html
7444 This is essentially an SSA-CCP pass modified to deal with ranges
7445 instead of constants.
7447 While propagating ranges, we may find that two or more SSA name
7448 have equivalent, though distinct ranges. For instance,
7451 2 p_4 = ASSERT_EXPR <p_3, p_3 != 0>
7453 4 p_5 = ASSERT_EXPR <p_4, p_4 == q_2>;
7457 In the code above, pointer p_5 has range [q_2, q_2], but from the
7458 code we can also determine that p_5 cannot be NULL and, if q_2 had
7459 a non-varying range, p_5's range should also be compatible with it.
7461 These equivalences are created by two expressions: ASSERT_EXPR and
7462 copy operations. Since p_5 is an assertion on p_4, and p_4 was the
7463 result of another assertion, then we can use the fact that p_5 and
7464 p_4 are equivalent when evaluating p_5's range.
7466 Together with value ranges, we also propagate these equivalences
7467 between names so that we can take advantage of information from
7468 multiple ranges when doing final replacement. Note that this
7469 equivalency relation is transitive but not symmetric.
7471 In the example above, p_5 is equivalent to p_4, q_2 and p_3, but we
7472 cannot assert that q_2 is equivalent to p_5 because q_2 may be used
7473 in contexts where that assertion does not hold (e.g., in line 6).
7475 TODO, the main difference between this pass and Patterson's is that
7476 we do not propagate edge probabilities. We only compute whether
7477 edges can be taken or not. That is, instead of having a spectrum
7478 of jump probabilities between 0 and 1, we only deal with 0, 1 and
7479 DON'T KNOW. In the future, it may be worthwhile to propagate
7480 probabilities to aid branch prediction. */
7489 loop_optimizer_init (LOOPS_NORMAL
| LOOPS_HAVE_RECORDED_EXITS
);
7490 rewrite_into_loop_closed_ssa (NULL
, TODO_update_ssa
);
7493 insert_range_assertions ();
7495 to_remove_edges
= VEC_alloc (edge
, heap
, 10);
7496 to_update_switch_stmts
= VEC_alloc (switch_update
, heap
, 5);
7497 threadedge_initialize_values ();
7500 ssa_propagate (vrp_visit_stmt
, vrp_visit_phi_node
);
7503 /* ASSERT_EXPRs must be removed before finalizing jump threads
7504 as finalizing jump threads calls the CFG cleanup code which
7505 does not properly handle ASSERT_EXPRs. */
7506 remove_range_assertions ();
7508 /* If we exposed any new variables, go ahead and put them into
7509 SSA form now, before we handle jump threading. This simplifies
7510 interactions between rewriting of _DECL nodes into SSA form
7511 and rewriting SSA_NAME nodes into SSA form after block
7512 duplication and CFG manipulation. */
7513 update_ssa (TODO_update_ssa
);
7515 finalize_jump_threads ();
7517 /* Remove dead edges from SWITCH_EXPR optimization. This leaves the
7518 CFG in a broken state and requires a cfg_cleanup run. */
7519 for (i
= 0; VEC_iterate (edge
, to_remove_edges
, i
, e
); ++i
)
7521 /* Update SWITCH_EXPR case label vector. */
7522 for (i
= 0; VEC_iterate (switch_update
, to_update_switch_stmts
, i
, su
); ++i
)
7525 size_t n
= TREE_VEC_LENGTH (su
->vec
);
7527 gimple_switch_set_num_labels (su
->stmt
, n
);
7528 for (j
= 0; j
< n
; j
++)
7529 gimple_switch_set_label (su
->stmt
, j
, TREE_VEC_ELT (su
->vec
, j
));
7530 /* As we may have replaced the default label with a regular one
7531 make sure to make it a real default label again. This ensures
7532 optimal expansion. */
7533 label
= gimple_switch_default_label (su
->stmt
);
7534 CASE_LOW (label
) = NULL_TREE
;
7535 CASE_HIGH (label
) = NULL_TREE
;
7538 if (VEC_length (edge
, to_remove_edges
) > 0)
7539 free_dominance_info (CDI_DOMINATORS
);
7541 VEC_free (edge
, heap
, to_remove_edges
);
7542 VEC_free (switch_update
, heap
, to_update_switch_stmts
);
7543 threadedge_finalize_values ();
7546 loop_optimizer_finalize ();
7553 return flag_tree_vrp
!= 0;
7556 struct gimple_opt_pass pass_vrp
=
7561 gate_vrp
, /* gate */
7562 execute_vrp
, /* execute */
7565 0, /* static_pass_number */
7566 TV_TREE_VRP
, /* tv_id */
7567 PROP_ssa
, /* properties_required */
7568 0, /* properties_provided */
7569 0, /* properties_destroyed */
7570 0, /* todo_flags_start */
7575 | TODO_update_ssa
/* todo_flags_finish */