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tree-vrp.c
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tree-vrp.c
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/* Support routines for Value Range Propagation (VRP).
Copyright (C) 2005, 2006, 2007, 2008, 2009, 2010
Free Software Foundation, Inc.
Contributed by Diego Novillo <dnovillo@redhat.com>.
This file is part of GCC.
GCC is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3, or (at your option)
any later version.
GCC is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with GCC; see the file COPYING3. If not see
<http://www.gnu.org/licenses/>. */
#include "config.h"
#include "system.h"
#include "coretypes.h"
#include "tm.h"
#include "ggc.h"
#include "flags.h"
#include "tree.h"
#include "basic-block.h"
#include "tree-flow.h"
#include "tree-pass.h"
#include "tree-dump.h"
#include "timevar.h"
#include "diagnostic.h"
#include "toplev.h"
#include "intl.h"
#include "cfgloop.h"
#include "tree-scalar-evolution.h"
#include "tree-ssa-propagate.h"
#include "tree-chrec.h"
/* Set of SSA names found live during the RPO traversal of the function
for still active basic-blocks. */
static sbitmap *live;
/* Return true if the SSA name NAME is live on the edge E. */
static bool
live_on_edge (edge e, tree name)
{
return (live[e->dest->index]
&& TEST_BIT (live[e->dest->index], SSA_NAME_VERSION (name)));
}
/* Local functions. */
static int compare_values (tree val1, tree val2);
static int compare_values_warnv (tree val1, tree val2, bool *);
static void vrp_meet (value_range_t *, value_range_t *);
static tree vrp_evaluate_conditional_warnv_with_ops (enum tree_code,
tree, tree, bool, bool *,
bool *);
/* Location information for ASSERT_EXPRs. Each instance of this
structure describes an ASSERT_EXPR for an SSA name. Since a single
SSA name may have more than one assertion associated with it, these
locations are kept in a linked list attached to the corresponding
SSA name. */
struct assert_locus_d
{
/* Basic block where the assertion would be inserted. */
basic_block bb;
/* Some assertions need to be inserted on an edge (e.g., assertions
generated by COND_EXPRs). In those cases, BB will be NULL. */
edge e;
/* Pointer to the statement that generated this assertion. */
gimple_stmt_iterator si;
/* Predicate code for the ASSERT_EXPR. Must be COMPARISON_CLASS_P. */
enum tree_code comp_code;
/* Value being compared against. */
tree val;
/* Expression to compare. */
tree expr;
/* Next node in the linked list. */
struct assert_locus_d *next;
};
typedef struct assert_locus_d *assert_locus_t;
/* If bit I is present, it means that SSA name N_i has a list of
assertions that should be inserted in the IL. */
static bitmap need_assert_for;
/* Array of locations lists where to insert assertions. ASSERTS_FOR[I]
holds a list of ASSERT_LOCUS_T nodes that describe where
ASSERT_EXPRs for SSA name N_I should be inserted. */
static assert_locus_t *asserts_for;
/* Value range array. After propagation, VR_VALUE[I] holds the range
of values that SSA name N_I may take. */
static value_range_t **vr_value;
/* For a PHI node which sets SSA name N_I, VR_COUNTS[I] holds the
number of executable edges we saw the last time we visited the
node. */
static int *vr_phi_edge_counts;
typedef struct {
gimple stmt;
tree vec;
} switch_update;
static VEC (edge, heap) *to_remove_edges;
DEF_VEC_O(switch_update);
DEF_VEC_ALLOC_O(switch_update, heap);
static VEC (switch_update, heap) *to_update_switch_stmts;
/* Return the maximum value for TYPE. */
static inline tree
vrp_val_max (const_tree type)
{
if (!INTEGRAL_TYPE_P (type))
return NULL_TREE;
return TYPE_MAX_VALUE (type);
}
/* Return the minimum value for TYPE. */
static inline tree
vrp_val_min (const_tree type)
{
if (!INTEGRAL_TYPE_P (type))
return NULL_TREE;
return TYPE_MIN_VALUE (type);
}
/* Return whether VAL is equal to the maximum value of its type. This
will be true for a positive overflow infinity. We can't do a
simple equality comparison with TYPE_MAX_VALUE because C typedefs
and Ada subtypes can produce types whose TYPE_MAX_VALUE is not ==
to the integer constant with the same value in the type. */
static inline bool
vrp_val_is_max (const_tree val)
{
tree type_max = vrp_val_max (TREE_TYPE (val));
return (val == type_max
|| (type_max != NULL_TREE
&& operand_equal_p (val, type_max, 0)));
}
/* Return whether VAL is equal to the minimum value of its type. This
will be true for a negative overflow infinity. */
static inline bool
vrp_val_is_min (const_tree val)
{
tree type_min = vrp_val_min (TREE_TYPE (val));
return (val == type_min
|| (type_min != NULL_TREE
&& operand_equal_p (val, type_min, 0)));
}
/* Return whether TYPE should use an overflow infinity distinct from
TYPE_{MIN,MAX}_VALUE. We use an overflow infinity value to
represent a signed overflow during VRP computations. An infinity
is distinct from a half-range, which will go from some number to
TYPE_{MIN,MAX}_VALUE. */
static inline bool
needs_overflow_infinity (const_tree type)
{
return INTEGRAL_TYPE_P (type) && !TYPE_OVERFLOW_WRAPS (type);
}
/* Return whether TYPE can support our overflow infinity
representation: we use the TREE_OVERFLOW flag, which only exists
for constants. If TYPE doesn't support this, we don't optimize
cases which would require signed overflow--we drop them to
VARYING. */
static inline bool
supports_overflow_infinity (const_tree type)
{
tree min = vrp_val_min (type), max = vrp_val_max (type);
#ifdef ENABLE_CHECKING
gcc_assert (needs_overflow_infinity (type));
#endif
return (min != NULL_TREE
&& CONSTANT_CLASS_P (min)
&& max != NULL_TREE
&& CONSTANT_CLASS_P (max));
}
/* VAL is the maximum or minimum value of a type. Return a
corresponding overflow infinity. */
static inline tree
make_overflow_infinity (tree val)
{
#ifdef ENABLE_CHECKING
gcc_assert (val != NULL_TREE && CONSTANT_CLASS_P (val));
#endif
val = copy_node (val);
TREE_OVERFLOW (val) = 1;
return val;
}
/* Return a negative overflow infinity for TYPE. */
static inline tree
negative_overflow_infinity (tree type)
{
#ifdef ENABLE_CHECKING
gcc_assert (supports_overflow_infinity (type));
#endif
return make_overflow_infinity (vrp_val_min (type));
}
/* Return a positive overflow infinity for TYPE. */
static inline tree
positive_overflow_infinity (tree type)
{
#ifdef ENABLE_CHECKING
gcc_assert (supports_overflow_infinity (type));
#endif
return make_overflow_infinity (vrp_val_max (type));
}
/* Return whether VAL is a negative overflow infinity. */
static inline bool
is_negative_overflow_infinity (const_tree val)
{
return (needs_overflow_infinity (TREE_TYPE (val))
&& CONSTANT_CLASS_P (val)
&& TREE_OVERFLOW (val)
&& vrp_val_is_min (val));
}
/* Return whether VAL is a positive overflow infinity. */
static inline bool
is_positive_overflow_infinity (const_tree val)
{
return (needs_overflow_infinity (TREE_TYPE (val))
&& CONSTANT_CLASS_P (val)
&& TREE_OVERFLOW (val)
&& vrp_val_is_max (val));
}
/* Return whether VAL is a positive or negative overflow infinity. */
static inline bool
is_overflow_infinity (const_tree val)
{
return (needs_overflow_infinity (TREE_TYPE (val))
&& CONSTANT_CLASS_P (val)
&& TREE_OVERFLOW (val)
&& (vrp_val_is_min (val) || vrp_val_is_max (val)));
}
/* Return whether STMT has a constant rhs that is_overflow_infinity. */
static inline bool
stmt_overflow_infinity (gimple stmt)
{
if (is_gimple_assign (stmt)
&& get_gimple_rhs_class (gimple_assign_rhs_code (stmt)) ==
GIMPLE_SINGLE_RHS)
return is_overflow_infinity (gimple_assign_rhs1 (stmt));
return false;
}
/* If VAL is now an overflow infinity, return VAL. Otherwise, return
the same value with TREE_OVERFLOW clear. This can be used to avoid
confusing a regular value with an overflow value. */
static inline tree
avoid_overflow_infinity (tree val)
{
if (!is_overflow_infinity (val))
return val;
if (vrp_val_is_max (val))
return vrp_val_max (TREE_TYPE (val));
else
{
#ifdef ENABLE_CHECKING
gcc_assert (vrp_val_is_min (val));
#endif
return vrp_val_min (TREE_TYPE (val));
}
}
/* Return true if ARG is marked with the nonnull attribute in the
current function signature. */
static bool
nonnull_arg_p (const_tree arg)
{
tree t, attrs, fntype;
unsigned HOST_WIDE_INT arg_num;
gcc_assert (TREE_CODE (arg) == PARM_DECL && POINTER_TYPE_P (TREE_TYPE (arg)));
/* The static chain decl is always non null. */
if (arg == cfun->static_chain_decl)
return true;
fntype = TREE_TYPE (current_function_decl);
attrs = lookup_attribute ("nonnull", TYPE_ATTRIBUTES (fntype));
/* If "nonnull" wasn't specified, we know nothing about the argument. */
if (attrs == NULL_TREE)
return false;
/* If "nonnull" applies to all the arguments, then ARG is non-null. */
if (TREE_VALUE (attrs) == NULL_TREE)
return true;
/* Get the position number for ARG in the function signature. */
for (arg_num = 1, t = DECL_ARGUMENTS (current_function_decl);
t;
t = TREE_CHAIN (t), arg_num++)
{
if (t == arg)
break;
}
gcc_assert (t == arg);
/* Now see if ARG_NUM is mentioned in the nonnull list. */
for (t = TREE_VALUE (attrs); t; t = TREE_CHAIN (t))
{
if (compare_tree_int (TREE_VALUE (t), arg_num) == 0)
return true;
}
return false;
}
/* Set value range VR to VR_VARYING. */
static inline void
set_value_range_to_varying (value_range_t *vr)
{
vr->type = VR_VARYING;
vr->min = vr->max = NULL_TREE;
if (vr->equiv)
bitmap_clear (vr->equiv);
}
/* Set value range VR to {T, MIN, MAX, EQUIV}. */
static void
set_value_range (value_range_t *vr, enum value_range_type t, tree min,
tree max, bitmap equiv)
{
#if defined ENABLE_CHECKING
/* Check the validity of the range. */
if (t == VR_RANGE || t == VR_ANTI_RANGE)
{
int cmp;
gcc_assert (min && max);
if (INTEGRAL_TYPE_P (TREE_TYPE (min)) && t == VR_ANTI_RANGE)
gcc_assert (!vrp_val_is_min (min) || !vrp_val_is_max (max));
cmp = compare_values (min, max);
gcc_assert (cmp == 0 || cmp == -1 || cmp == -2);
if (needs_overflow_infinity (TREE_TYPE (min)))
gcc_assert (!is_overflow_infinity (min)
|| !is_overflow_infinity (max));
}
if (t == VR_UNDEFINED || t == VR_VARYING)
gcc_assert (min == NULL_TREE && max == NULL_TREE);
if (t == VR_UNDEFINED || t == VR_VARYING)
gcc_assert (equiv == NULL || bitmap_empty_p (equiv));
#endif
vr->type = t;
vr->min = min;
vr->max = max;
/* Since updating the equivalence set involves deep copying the
bitmaps, only do it if absolutely necessary. */
if (vr->equiv == NULL
&& equiv != NULL)
vr->equiv = BITMAP_ALLOC (NULL);
if (equiv != vr->equiv)
{
if (equiv && !bitmap_empty_p (equiv))
bitmap_copy (vr->equiv, equiv);
else
bitmap_clear (vr->equiv);
}
}
/* Set value range VR to the canonical form of {T, MIN, MAX, EQUIV}.
This means adjusting T, MIN and MAX representing the case of a
wrapping range with MAX < MIN covering [MIN, type_max] U [type_min, MAX]
as anti-rage ~[MAX+1, MIN-1]. Likewise for wrapping anti-ranges.
In corner cases where MAX+1 or MIN-1 wraps this will fall back
to varying.
This routine exists to ease canonicalization in the case where we
extract ranges from var + CST op limit. */
static void
set_and_canonicalize_value_range (value_range_t *vr, enum value_range_type t,
tree min, tree max, bitmap equiv)
{
/* Nothing to canonicalize for symbolic or unknown or varying ranges. */
if ((t != VR_RANGE
&& t != VR_ANTI_RANGE)
|| TREE_CODE (min) != INTEGER_CST
|| TREE_CODE (max) != INTEGER_CST)
{
set_value_range (vr, t, min, max, equiv);
return;
}
/* Wrong order for min and max, to swap them and the VR type we need
to adjust them. */
if (tree_int_cst_lt (max, min))
{
tree one = build_int_cst (TREE_TYPE (min), 1);
tree tmp = int_const_binop (PLUS_EXPR, max, one, 0);
max = int_const_binop (MINUS_EXPR, min, one, 0);
min = tmp;
/* There's one corner case, if we had [C+1, C] before we now have
that again. But this represents an empty value range, so drop
to varying in this case. */
if (tree_int_cst_lt (max, min))
{
set_value_range_to_varying (vr);
return;
}
t = t == VR_RANGE ? VR_ANTI_RANGE : VR_RANGE;
}
/* Anti-ranges that can be represented as ranges should be so. */
if (t == VR_ANTI_RANGE)
{
bool is_min = vrp_val_is_min (min);
bool is_max = vrp_val_is_max (max);
if (is_min && is_max)
{
/* We cannot deal with empty ranges, drop to varying. */
set_value_range_to_varying (vr);
return;
}
else if (is_min
/* As a special exception preserve non-null ranges. */
&& !(TYPE_UNSIGNED (TREE_TYPE (min))
&& integer_zerop (max)))
{
tree one = build_int_cst (TREE_TYPE (max), 1);
min = int_const_binop (PLUS_EXPR, max, one, 0);
max = vrp_val_max (TREE_TYPE (max));
t = VR_RANGE;
}
else if (is_max)
{
tree one = build_int_cst (TREE_TYPE (min), 1);
max = int_const_binop (MINUS_EXPR, min, one, 0);
min = vrp_val_min (TREE_TYPE (min));
t = VR_RANGE;
}
}
set_value_range (vr, t, min, max, equiv);
}
/* Copy value range FROM into value range TO. */
static inline void
copy_value_range (value_range_t *to, value_range_t *from)
{
set_value_range (to, from->type, from->min, from->max, from->equiv);
}
/* Set value range VR to a single value. This function is only called
with values we get from statements, and exists to clear the
TREE_OVERFLOW flag so that we don't think we have an overflow
infinity when we shouldn't. */
static inline void
set_value_range_to_value (value_range_t *vr, tree val, bitmap equiv)
{
gcc_assert (is_gimple_min_invariant (val));
val = avoid_overflow_infinity (val);
set_value_range (vr, VR_RANGE, val, val, equiv);
}
/* Set value range VR to a non-negative range of type TYPE.
OVERFLOW_INFINITY indicates whether to use an overflow infinity
rather than TYPE_MAX_VALUE; this should be true if we determine
that the range is nonnegative based on the assumption that signed
overflow does not occur. */
static inline void
set_value_range_to_nonnegative (value_range_t *vr, tree type,
bool overflow_infinity)
{
tree zero;
if (overflow_infinity && !supports_overflow_infinity (type))
{
set_value_range_to_varying (vr);
return;
}
zero = build_int_cst (type, 0);
set_value_range (vr, VR_RANGE, zero,
(overflow_infinity
? positive_overflow_infinity (type)
: TYPE_MAX_VALUE (type)),
vr->equiv);
}
/* Set value range VR to a non-NULL range of type TYPE. */
static inline void
set_value_range_to_nonnull (value_range_t *vr, tree type)
{
tree zero = build_int_cst (type, 0);
set_value_range (vr, VR_ANTI_RANGE, zero, zero, vr->equiv);
}
/* Set value range VR to a NULL range of type TYPE. */
static inline void
set_value_range_to_null (value_range_t *vr, tree type)
{
set_value_range_to_value (vr, build_int_cst (type, 0), vr->equiv);
}
/* Set value range VR to a range of a truthvalue of type TYPE. */
static inline void
set_value_range_to_truthvalue (value_range_t *vr, tree type)
{
if (TYPE_PRECISION (type) == 1)
set_value_range_to_varying (vr);
else
set_value_range (vr, VR_RANGE,
build_int_cst (type, 0), build_int_cst (type, 1),
vr->equiv);
}
/* Set value range VR to VR_UNDEFINED. */
static inline void
set_value_range_to_undefined (value_range_t *vr)
{
vr->type = VR_UNDEFINED;
vr->min = vr->max = NULL_TREE;
if (vr->equiv)
bitmap_clear (vr->equiv);
}
/* If abs (min) < abs (max), set VR to [-max, max], if
abs (min) >= abs (max), set VR to [-min, min]. */
static void
abs_extent_range (value_range_t *vr, tree min, tree max)
{
int cmp;
gcc_assert (TREE_CODE (min) == INTEGER_CST);
gcc_assert (TREE_CODE (max) == INTEGER_CST);
gcc_assert (INTEGRAL_TYPE_P (TREE_TYPE (min)));
gcc_assert (!TYPE_UNSIGNED (TREE_TYPE (min)));
min = fold_unary (ABS_EXPR, TREE_TYPE (min), min);
max = fold_unary (ABS_EXPR, TREE_TYPE (max), max);
if (TREE_OVERFLOW (min) || TREE_OVERFLOW (max))
{
set_value_range_to_varying (vr);
return;
}
cmp = compare_values (min, max);
if (cmp == -1)
min = fold_unary (NEGATE_EXPR, TREE_TYPE (min), max);
else if (cmp == 0 || cmp == 1)
{
max = min;
min = fold_unary (NEGATE_EXPR, TREE_TYPE (min), min);
}
else
{
set_value_range_to_varying (vr);
return;
}
set_and_canonicalize_value_range (vr, VR_RANGE, min, max, NULL);
}
/* Return value range information for VAR.
If we have no values ranges recorded (ie, VRP is not running), then
return NULL. Otherwise create an empty range if none existed for VAR. */
static value_range_t *
get_value_range (const_tree var)
{
value_range_t *vr;
tree sym;
unsigned ver = SSA_NAME_VERSION (var);
/* If we have no recorded ranges, then return NULL. */
if (! vr_value)
return NULL;
vr = vr_value[ver];
if (vr)
return vr;
/* Create a default value range. */
vr_value[ver] = vr = XCNEW (value_range_t);
/* Defer allocating the equivalence set. */
vr->equiv = NULL;
/* If VAR is a default definition, the variable can take any value
in VAR's type. */
sym = SSA_NAME_VAR (var);
if (SSA_NAME_IS_DEFAULT_DEF (var))
{
/* Try to use the "nonnull" attribute to create ~[0, 0]
anti-ranges for pointers. Note that this is only valid with
default definitions of PARM_DECLs. */
if (TREE_CODE (sym) == PARM_DECL
&& POINTER_TYPE_P (TREE_TYPE (sym))
&& nonnull_arg_p (sym))
set_value_range_to_nonnull (vr, TREE_TYPE (sym));
else
set_value_range_to_varying (vr);
}
return vr;
}
/* Return true, if VAL1 and VAL2 are equal values for VRP purposes. */
static inline bool
vrp_operand_equal_p (const_tree val1, const_tree val2)
{
if (val1 == val2)
return true;
if (!val1 || !val2 || !operand_equal_p (val1, val2, 0))
return false;
if (is_overflow_infinity (val1))
return is_overflow_infinity (val2);
return true;
}
/* Return true, if the bitmaps B1 and B2 are equal. */
static inline bool
vrp_bitmap_equal_p (const_bitmap b1, const_bitmap b2)
{
return (b1 == b2
|| (b1 && b2
&& bitmap_equal_p (b1, b2)));
}
/* Update the value range and equivalence set for variable VAR to
NEW_VR. Return true if NEW_VR is different from VAR's previous
value.
NOTE: This function assumes that NEW_VR is a temporary value range
object created for the sole purpose of updating VAR's range. The
storage used by the equivalence set from NEW_VR will be freed by
this function. Do not call update_value_range when NEW_VR
is the range object associated with another SSA name. */
static inline bool
update_value_range (const_tree var, value_range_t *new_vr)
{
value_range_t *old_vr;
bool is_new;
/* Update the value range, if necessary. */
old_vr = get_value_range (var);
is_new = old_vr->type != new_vr->type
|| !vrp_operand_equal_p (old_vr->min, new_vr->min)
|| !vrp_operand_equal_p (old_vr->max, new_vr->max)
|| !vrp_bitmap_equal_p (old_vr->equiv, new_vr->equiv);
if (is_new)
set_value_range (old_vr, new_vr->type, new_vr->min, new_vr->max,
new_vr->equiv);
BITMAP_FREE (new_vr->equiv);
return is_new;
}
/* Add VAR and VAR's equivalence set to EQUIV. This is the central
point where equivalence processing can be turned on/off. */
static void
add_equivalence (bitmap *equiv, const_tree var)
{
unsigned ver = SSA_NAME_VERSION (var);
value_range_t *vr = vr_value[ver];
if (*equiv == NULL)
*equiv = BITMAP_ALLOC (NULL);
bitmap_set_bit (*equiv, ver);
if (vr && vr->equiv)
bitmap_ior_into (*equiv, vr->equiv);
}
/* Return true if VR is ~[0, 0]. */
static inline bool
range_is_nonnull (value_range_t *vr)
{
return vr->type == VR_ANTI_RANGE
&& integer_zerop (vr->min)
&& integer_zerop (vr->max);
}
/* Return true if VR is [0, 0]. */
static inline bool
range_is_null (value_range_t *vr)
{
return vr->type == VR_RANGE
&& integer_zerop (vr->min)
&& integer_zerop (vr->max);
}
/* Return true if value range VR involves at least one symbol. */
static inline bool
symbolic_range_p (value_range_t *vr)
{
return (!is_gimple_min_invariant (vr->min)
|| !is_gimple_min_invariant (vr->max));
}
/* Return true if value range VR uses an overflow infinity. */
static inline bool
overflow_infinity_range_p (value_range_t *vr)
{
return (vr->type == VR_RANGE
&& (is_overflow_infinity (vr->min)
|| is_overflow_infinity (vr->max)));
}
/* Return false if we can not make a valid comparison based on VR;
this will be the case if it uses an overflow infinity and overflow
is not undefined (i.e., -fno-strict-overflow is in effect).
Otherwise return true, and set *STRICT_OVERFLOW_P to true if VR
uses an overflow infinity. */
static bool
usable_range_p (value_range_t *vr, bool *strict_overflow_p)
{
gcc_assert (vr->type == VR_RANGE);
if (is_overflow_infinity (vr->min))
{
*strict_overflow_p = true;
if (!TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (vr->min)))
return false;
}
if (is_overflow_infinity (vr->max))
{
*strict_overflow_p = true;
if (!TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (vr->max)))
return false;
}
return true;
}
/* Like tree_expr_nonnegative_warnv_p, but this function uses value
ranges obtained so far. */
static bool
vrp_expr_computes_nonnegative (tree expr, bool *strict_overflow_p)
{
return (tree_expr_nonnegative_warnv_p (expr, strict_overflow_p)
|| (TREE_CODE (expr) == SSA_NAME
&& ssa_name_nonnegative_p (expr)));
}
/* Return true if the result of assignment STMT is know to be non-negative.
If the return value is based on the assumption that signed overflow is
undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't change
*STRICT_OVERFLOW_P.*/
static bool
gimple_assign_nonnegative_warnv_p (gimple stmt, bool *strict_overflow_p)
{
enum tree_code code = gimple_assign_rhs_code (stmt);
switch (get_gimple_rhs_class (code))
{
case GIMPLE_UNARY_RHS:
return tree_unary_nonnegative_warnv_p (gimple_assign_rhs_code (stmt),
gimple_expr_type (stmt),
gimple_assign_rhs1 (stmt),
strict_overflow_p);
case GIMPLE_BINARY_RHS:
return tree_binary_nonnegative_warnv_p (gimple_assign_rhs_code (stmt),
gimple_expr_type (stmt),
gimple_assign_rhs1 (stmt),
gimple_assign_rhs2 (stmt),
strict_overflow_p);
case GIMPLE_SINGLE_RHS:
return tree_single_nonnegative_warnv_p (gimple_assign_rhs1 (stmt),
strict_overflow_p);
case GIMPLE_INVALID_RHS:
gcc_unreachable ();
default:
gcc_unreachable ();
}
}
/* Return true if return value of call STMT is know to be non-negative.
If the return value is based on the assumption that signed overflow is
undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't change
*STRICT_OVERFLOW_P.*/
static bool
gimple_call_nonnegative_warnv_p (gimple stmt, bool *strict_overflow_p)
{
tree arg0 = gimple_call_num_args (stmt) > 0 ?
gimple_call_arg (stmt, 0) : NULL_TREE;
tree arg1 = gimple_call_num_args (stmt) > 1 ?
gimple_call_arg (stmt, 1) : NULL_TREE;
return tree_call_nonnegative_warnv_p (gimple_expr_type (stmt),
gimple_call_fndecl (stmt),
arg0,
arg1,
strict_overflow_p);
}
/* Return true if STMT is know to to compute a non-negative value.
If the return value is based on the assumption that signed overflow is
undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't change
*STRICT_OVERFLOW_P.*/
static bool
gimple_stmt_nonnegative_warnv_p (gimple stmt, bool *strict_overflow_p)
{
switch (gimple_code (stmt))
{
case GIMPLE_ASSIGN:
return gimple_assign_nonnegative_warnv_p (stmt, strict_overflow_p);
case GIMPLE_CALL:
return gimple_call_nonnegative_warnv_p (stmt, strict_overflow_p);
default:
gcc_unreachable ();
}
}
/* Return true if the result of assignment STMT is know to be non-zero.
If the return value is based on the assumption that signed overflow is
undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't change
*STRICT_OVERFLOW_P.*/
static bool
gimple_assign_nonzero_warnv_p (gimple stmt, bool *strict_overflow_p)
{
enum tree_code code = gimple_assign_rhs_code (stmt);
switch (get_gimple_rhs_class (code))
{
case GIMPLE_UNARY_RHS:
return tree_unary_nonzero_warnv_p (gimple_assign_rhs_code (stmt),
gimple_expr_type (stmt),
gimple_assign_rhs1 (stmt),
strict_overflow_p);
case GIMPLE_BINARY_RHS:
return tree_binary_nonzero_warnv_p (gimple_assign_rhs_code (stmt),
gimple_expr_type (stmt),
gimple_assign_rhs1 (stmt),
gimple_assign_rhs2 (stmt),
strict_overflow_p);
case GIMPLE_SINGLE_RHS:
return tree_single_nonzero_warnv_p (gimple_assign_rhs1 (stmt),
strict_overflow_p);
case GIMPLE_INVALID_RHS:
gcc_unreachable ();
default:
gcc_unreachable ();
}
}
/* Return true if STMT is know to to compute a non-zero value.
If the return value is based on the assumption that signed overflow is
undefined, set *STRICT_OVERFLOW_P to true; otherwise, don't change
*STRICT_OVERFLOW_P.*/
static bool
gimple_stmt_nonzero_warnv_p (gimple stmt, bool *strict_overflow_p)
{
switch (gimple_code (stmt))
{
case GIMPLE_ASSIGN:
return gimple_assign_nonzero_warnv_p (stmt, strict_overflow_p);
case GIMPLE_CALL:
return gimple_alloca_call_p (stmt);
default:
gcc_unreachable ();
}
}
/* Like tree_expr_nonzero_warnv_p, but this function uses value ranges
obtained so far. */
static bool
vrp_stmt_computes_nonzero (gimple stmt, bool *strict_overflow_p)
{
if (gimple_stmt_nonzero_warnv_p (stmt, strict_overflow_p))
return true;
/* If we have an expression of the form &X->a, then the expression
is nonnull if X is nonnull. */
if (is_gimple_assign (stmt)
&& gimple_assign_rhs_code (stmt) == ADDR_EXPR)
{
tree expr = gimple_assign_rhs1 (stmt);
tree base = get_base_address (TREE_OPERAND (expr, 0));
if (base != NULL_TREE
&& TREE_CODE (base) == INDIRECT_REF
&& TREE_CODE (TREE_OPERAND (base, 0)) == SSA_NAME)
{
value_range_t *vr = get_value_range (TREE_OPERAND (base, 0));
if (range_is_nonnull (vr))
return true;
}
}
return false;
}
/* Returns true if EXPR is a valid value (as expected by compare_values) --
a gimple invariant, or SSA_NAME +- CST. */
static bool
valid_value_p (tree expr)
{
if (TREE_CODE (expr) == SSA_NAME)
return true;
if (TREE_CODE (expr) == PLUS_EXPR
|| TREE_CODE (expr) == MINUS_EXPR)
return (TREE_CODE (TREE_OPERAND (expr, 0)) == SSA_NAME
&& TREE_CODE (TREE_OPERAND (expr, 1)) == INTEGER_CST);
return is_gimple_min_invariant (expr);
}
/* Return
1 if VAL < VAL2
0 if !(VAL < VAL2)
-2 if those are incomparable. */
static inline int
operand_less_p (tree val, tree val2)
{
/* LT is folded faster than GE and others. Inline the common case. */