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/* Code for range operators.
Copyright (C) 2017-2022 Free Software Foundation, Inc.
Contributed by Andrew MacLeod <amacleod@redhat.com>
and Aldy Hernandez <aldyh@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 "backend.h"
#include "insn-codes.h"
#include "rtl.h"
#include "tree.h"
#include "gimple.h"
#include "cfghooks.h"
#include "tree-pass.h"
#include "ssa.h"
#include "optabs-tree.h"
#include "gimple-pretty-print.h"
#include "diagnostic-core.h"
#include "flags.h"
#include "fold-const.h"
#include "stor-layout.h"
#include "calls.h"
#include "cfganal.h"
#include "gimple-iterator.h"
#include "gimple-fold.h"
#include "tree-eh.h"
#include "gimple-walk.h"
#include "tree-cfg.h"
#include "wide-int.h"
#include "value-relation.h"
#include "range-op.h"
#include "tree-ssa-ccp.h"
// Convert irange bitmasks into a VALUE MASK pair suitable for calling CCP.
static void
irange_to_masked_value (const irange &r, widest_int &value, widest_int &mask)
{
if (r.singleton_p ())
{
mask = 0;
value = widest_int::from (r.lower_bound (), TYPE_SIGN (r.type ()));
}
else
{
mask = widest_int::from (r.get_nonzero_bits (), TYPE_SIGN (r.type ()));
value = 0;
}
}
// Update the known bitmasks in R when applying the operation CODE to
// LH and RH.
static void
update_known_bitmask (irange &r, tree_code code,
const irange &lh, const irange &rh)
{
if (r.undefined_p () || lh.undefined_p () || rh.undefined_p ())
return;
widest_int value, mask, lh_mask, rh_mask, lh_value, rh_value;
tree type = r.type ();
signop sign = TYPE_SIGN (type);
int prec = TYPE_PRECISION (type);
signop lh_sign = TYPE_SIGN (lh.type ());
signop rh_sign = TYPE_SIGN (rh.type ());
int lh_prec = TYPE_PRECISION (lh.type ());
int rh_prec = TYPE_PRECISION (rh.type ());
irange_to_masked_value (lh, lh_value, lh_mask);
irange_to_masked_value (rh, rh_value, rh_mask);
bit_value_binop (code, sign, prec, &value, &mask,
lh_sign, lh_prec, lh_value, lh_mask,
rh_sign, rh_prec, rh_value, rh_mask);
r.set_nonzero_bits (value | mask);
}
// Return the upper limit for a type.
static inline wide_int
max_limit (const_tree type)
{
return wi::max_value (TYPE_PRECISION (type) , TYPE_SIGN (type));
}
// Return the lower limit for a type.
static inline wide_int
min_limit (const_tree type)
{
return wi::min_value (TYPE_PRECISION (type) , TYPE_SIGN (type));
}
// Return false if shifting by OP is undefined behavior. Otherwise, return
// true and the range it is to be shifted by. This allows trimming out of
// undefined ranges, leaving only valid ranges if there are any.
static inline bool
get_shift_range (irange &r, tree type, const irange &op)
{
if (op.undefined_p ())
return false;
// Build valid range and intersect it with the shift range.
r = value_range (build_int_cst_type (op.type (), 0),
build_int_cst_type (op.type (), TYPE_PRECISION (type) - 1));
r.intersect (op);
// If there are no valid ranges in the shift range, returned false.
if (r.undefined_p ())
return false;
return true;
}
// Return TRUE if 0 is within [WMIN, WMAX].
static inline bool
wi_includes_zero_p (tree type, const wide_int &wmin, const wide_int &wmax)
{
signop sign = TYPE_SIGN (type);
return wi::le_p (wmin, 0, sign) && wi::ge_p (wmax, 0, sign);
}
// Return TRUE if [WMIN, WMAX] is the singleton 0.
static inline bool
wi_zero_p (tree type, const wide_int &wmin, const wide_int &wmax)
{
unsigned prec = TYPE_PRECISION (type);
return wmin == wmax && wi::eq_p (wmin, wi::zero (prec));
}
// Default wide_int fold operation returns [MIN, MAX].
void
range_operator::wi_fold (irange &r, tree type,
const wide_int &lh_lb ATTRIBUTE_UNUSED,
const wide_int &lh_ub ATTRIBUTE_UNUSED,
const wide_int &rh_lb ATTRIBUTE_UNUSED,
const wide_int &rh_ub ATTRIBUTE_UNUSED) const
{
gcc_checking_assert (r.supports_type_p (type));
r.set_varying (type);
}
// Call wi_fold, except further split small subranges into constants.
// This can provide better precision. For something 8 >> [0,1]
// Instead of [8, 16], we will produce [8,8][16,16]
void
range_operator::wi_fold_in_parts (irange &r, tree type,
const wide_int &lh_lb,
const wide_int &lh_ub,
const wide_int &rh_lb,
const wide_int &rh_ub) const
{
int_range_max tmp;
widest_int rh_range = wi::sub (widest_int::from (rh_ub, TYPE_SIGN (type)),
widest_int::from (rh_lb, TYPE_SIGN (type)));
widest_int lh_range = wi::sub (widest_int::from (lh_ub, TYPE_SIGN (type)),
widest_int::from (lh_lb, TYPE_SIGN (type)));
// If there are 2, 3, or 4 values in the RH range, do them separately.
// Call wi_fold_in_parts to check the RH side.
if (rh_range > 0 && rh_range < 4)
{
wi_fold_in_parts (r, type, lh_lb, lh_ub, rh_lb, rh_lb);
if (rh_range > 1)
{
wi_fold_in_parts (tmp, type, lh_lb, lh_ub, rh_lb + 1, rh_lb + 1);
r.union_ (tmp);
if (rh_range == 3)
{
wi_fold_in_parts (tmp, type, lh_lb, lh_ub, rh_lb + 2, rh_lb + 2);
r.union_ (tmp);
}
}
wi_fold_in_parts (tmp, type, lh_lb, lh_ub, rh_ub, rh_ub);
r.union_ (tmp);
}
// Otherise check for 2, 3, or 4 values in the LH range and split them up.
// The RH side has been checked, so no recursion needed.
else if (lh_range > 0 && lh_range < 4)
{
wi_fold (r, type, lh_lb, lh_lb, rh_lb, rh_ub);
if (lh_range > 1)
{
wi_fold (tmp, type, lh_lb + 1, lh_lb + 1, rh_lb, rh_ub);
r.union_ (tmp);
if (lh_range == 3)
{
wi_fold (tmp, type, lh_lb + 2, lh_lb + 2, rh_lb, rh_ub);
r.union_ (tmp);
}
}
wi_fold (tmp, type, lh_ub, lh_ub, rh_lb, rh_ub);
r.union_ (tmp);
}
// Otherwise just call wi_fold.
else
wi_fold (r, type, lh_lb, lh_ub, rh_lb, rh_ub);
}
// The default for fold is to break all ranges into sub-ranges and
// invoke the wi_fold method on each sub-range pair.
bool
range_operator::fold_range (irange &r, tree type,
const irange &lh,
const irange &rh,
relation_trio trio) const
{
gcc_checking_assert (r.supports_type_p (type));
if (empty_range_varying (r, type, lh, rh))
return true;
relation_kind rel = trio.op1_op2 ();
unsigned num_lh = lh.num_pairs ();
unsigned num_rh = rh.num_pairs ();
// If both ranges are single pairs, fold directly into the result range.
// If the number of subranges grows too high, produce a summary result as the
// loop becomes exponential with little benefit. See PR 103821.
if ((num_lh == 1 && num_rh == 1) || num_lh * num_rh > 12)
{
wi_fold_in_parts (r, type, lh.lower_bound (), lh.upper_bound (),
rh.lower_bound (), rh.upper_bound ());
op1_op2_relation_effect (r, type, lh, rh, rel);
update_known_bitmask (r, m_code, lh, rh);
return true;
}
int_range_max tmp;
r.set_undefined ();
for (unsigned x = 0; x < num_lh; ++x)
for (unsigned y = 0; y < num_rh; ++y)
{
wide_int lh_lb = lh.lower_bound (x);
wide_int lh_ub = lh.upper_bound (x);
wide_int rh_lb = rh.lower_bound (y);
wide_int rh_ub = rh.upper_bound (y);
wi_fold_in_parts (tmp, type, lh_lb, lh_ub, rh_lb, rh_ub);
r.union_ (tmp);
if (r.varying_p ())
{
op1_op2_relation_effect (r, type, lh, rh, rel);
update_known_bitmask (r, m_code, lh, rh);
return true;
}
}
op1_op2_relation_effect (r, type, lh, rh, rel);
update_known_bitmask (r, m_code, lh, rh);
return true;
}
// The default for op1_range is to return false.
bool
range_operator::op1_range (irange &r ATTRIBUTE_UNUSED,
tree type ATTRIBUTE_UNUSED,
const irange &lhs ATTRIBUTE_UNUSED,
const irange &op2 ATTRIBUTE_UNUSED,
relation_trio) const
{
return false;
}
// The default for op2_range is to return false.
bool
range_operator::op2_range (irange &r ATTRIBUTE_UNUSED,
tree type ATTRIBUTE_UNUSED,
const irange &lhs ATTRIBUTE_UNUSED,
const irange &op1 ATTRIBUTE_UNUSED,
relation_trio) const
{
return false;
}
// The default relation routines return VREL_VARYING.
relation_kind
range_operator::lhs_op1_relation (const irange &lhs ATTRIBUTE_UNUSED,
const irange &op1 ATTRIBUTE_UNUSED,
const irange &op2 ATTRIBUTE_UNUSED,
relation_kind rel ATTRIBUTE_UNUSED) const
{
return VREL_VARYING;
}
relation_kind
range_operator::lhs_op2_relation (const irange &lhs ATTRIBUTE_UNUSED,
const irange &op1 ATTRIBUTE_UNUSED,
const irange &op2 ATTRIBUTE_UNUSED,
relation_kind rel ATTRIBUTE_UNUSED) const
{
return VREL_VARYING;
}
relation_kind
range_operator::op1_op2_relation (const irange &lhs ATTRIBUTE_UNUSED) const
{
return VREL_VARYING;
}
// Default is no relation affects the LHS.
bool
range_operator::op1_op2_relation_effect (irange &lhs_range ATTRIBUTE_UNUSED,
tree type ATTRIBUTE_UNUSED,
const irange &op1_range ATTRIBUTE_UNUSED,
const irange &op2_range ATTRIBUTE_UNUSED,
relation_kind rel ATTRIBUTE_UNUSED) const
{
return false;
}
// Create and return a range from a pair of wide-ints that are known
// to have overflowed (or underflowed).
static void
value_range_from_overflowed_bounds (irange &r, tree type,
const wide_int &wmin,
const wide_int &wmax)
{
const signop sgn = TYPE_SIGN (type);
const unsigned int prec = TYPE_PRECISION (type);
wide_int tmin = wide_int::from (wmin, prec, sgn);
wide_int tmax = wide_int::from (wmax, prec, sgn);
bool covers = false;
wide_int tem = tmin;
tmin = tmax + 1;
if (wi::cmp (tmin, tmax, sgn) < 0)
covers = true;
tmax = tem - 1;
if (wi::cmp (tmax, tem, sgn) > 0)
covers = true;
// If the anti-range would cover nothing, drop to varying.
// Likewise if the anti-range bounds are outside of the types
// values.
if (covers || wi::cmp (tmin, tmax, sgn) > 0)
r.set_varying (type);
else
{
tree tree_min = wide_int_to_tree (type, tmin);
tree tree_max = wide_int_to_tree (type, tmax);
r.set (tree_min, tree_max, VR_ANTI_RANGE);
}
}
// Create and return a range from a pair of wide-ints. MIN_OVF and
// MAX_OVF describe any overflow that might have occurred while
// calculating WMIN and WMAX respectively.
static void
value_range_with_overflow (irange &r, tree type,
const wide_int &wmin, const wide_int &wmax,
wi::overflow_type min_ovf = wi::OVF_NONE,
wi::overflow_type max_ovf = wi::OVF_NONE)
{
const signop sgn = TYPE_SIGN (type);
const unsigned int prec = TYPE_PRECISION (type);
const bool overflow_wraps = TYPE_OVERFLOW_WRAPS (type);
// For one bit precision if max != min, then the range covers all
// values.
if (prec == 1 && wi::ne_p (wmax, wmin))
{
r.set_varying (type);
return;
}
if (overflow_wraps)
{
// If overflow wraps, truncate the values and adjust the range,
// kind, and bounds appropriately.
if ((min_ovf != wi::OVF_NONE) == (max_ovf != wi::OVF_NONE))
{
wide_int tmin = wide_int::from (wmin, prec, sgn);
wide_int tmax = wide_int::from (wmax, prec, sgn);
// If the limits are swapped, we wrapped around and cover
// the entire range.
if (wi::gt_p (tmin, tmax, sgn))
r.set_varying (type);
else
// No overflow or both overflow or underflow. The range
// kind stays normal.
r.set (wide_int_to_tree (type, tmin),
wide_int_to_tree (type, tmax));
return;
}
if ((min_ovf == wi::OVF_UNDERFLOW && max_ovf == wi::OVF_NONE)
|| (max_ovf == wi::OVF_OVERFLOW && min_ovf == wi::OVF_NONE))
value_range_from_overflowed_bounds (r, type, wmin, wmax);
else
// Other underflow and/or overflow, drop to VR_VARYING.
r.set_varying (type);
}
else
{
// If both bounds either underflowed or overflowed, then the result
// is undefined.
if ((min_ovf == wi::OVF_OVERFLOW && max_ovf == wi::OVF_OVERFLOW)
|| (min_ovf == wi::OVF_UNDERFLOW && max_ovf == wi::OVF_UNDERFLOW))
{
r.set_undefined ();
return;
}
// If overflow does not wrap, saturate to [MIN, MAX].
wide_int new_lb, new_ub;
if (min_ovf == wi::OVF_UNDERFLOW)
new_lb = wi::min_value (prec, sgn);
else if (min_ovf == wi::OVF_OVERFLOW)
new_lb = wi::max_value (prec, sgn);
else
new_lb = wmin;
if (max_ovf == wi::OVF_UNDERFLOW)
new_ub = wi::min_value (prec, sgn);
else if (max_ovf == wi::OVF_OVERFLOW)
new_ub = wi::max_value (prec, sgn);
else
new_ub = wmax;
r.set (wide_int_to_tree (type, new_lb),
wide_int_to_tree (type, new_ub));
}
}
// Create and return a range from a pair of wide-ints. Canonicalize
// the case where the bounds are swapped. In which case, we transform
// [10,5] into [MIN,5][10,MAX].
static inline void
create_possibly_reversed_range (irange &r, tree type,
const wide_int &new_lb, const wide_int &new_ub)
{
signop s = TYPE_SIGN (type);
// If the bounds are swapped, treat the result as if an overflow occured.
if (wi::gt_p (new_lb, new_ub, s))
value_range_from_overflowed_bounds (r, type, new_lb, new_ub);
else
// Otherwise it's just a normal range.
r.set (wide_int_to_tree (type, new_lb), wide_int_to_tree (type, new_ub));
}
// Return the summary information about boolean range LHS. If EMPTY/FULL,
// return the equivalent range for TYPE in R; if FALSE/TRUE, do nothing.
bool_range_state
get_bool_state (vrange &r, const vrange &lhs, tree val_type)
{
// If there is no result, then this is unexecutable.
if (lhs.undefined_p ())
{
r.set_undefined ();
return BRS_EMPTY;
}
if (lhs.zero_p ())
return BRS_FALSE;
// For TRUE, we can't just test for [1,1] because Ada can have
// multi-bit booleans, and TRUE values can be: [1, MAX], ~[0], etc.
if (lhs.contains_p (build_zero_cst (lhs.type ())))
{
r.set_varying (val_type);
return BRS_FULL;
}
return BRS_TRUE;
}
class operator_equal : public range_operator
{
using range_operator::fold_range;
using range_operator::op1_range;
using range_operator::op2_range;
public:
virtual bool fold_range (irange &r, tree type,
const irange &op1,
const irange &op2,
relation_trio = TRIO_VARYING) const;
virtual bool op1_range (irange &r, tree type,
const irange &lhs,
const irange &val,
relation_trio = TRIO_VARYING) const;
virtual bool op2_range (irange &r, tree type,
const irange &lhs,
const irange &val,
relation_trio = TRIO_VARYING) const;
virtual relation_kind op1_op2_relation (const irange &lhs) const;
} op_equal;
// Check if the LHS range indicates a relation between OP1 and OP2.
relation_kind
equal_op1_op2_relation (const irange &lhs)
{
if (lhs.undefined_p ())
return VREL_UNDEFINED;
// FALSE = op1 == op2 indicates NE_EXPR.
if (lhs.zero_p ())
return VREL_NE;
// TRUE = op1 == op2 indicates EQ_EXPR.
if (!lhs.contains_p (build_zero_cst (lhs.type ())))
return VREL_EQ;
return VREL_VARYING;
}
relation_kind
operator_equal::op1_op2_relation (const irange &lhs) const
{
return equal_op1_op2_relation (lhs);
}
bool
operator_equal::fold_range (irange &r, tree type,
const irange &op1,
const irange &op2,
relation_trio rel) const
{
if (relop_early_resolve (r, type, op1, op2, rel, VREL_EQ))
return true;
// We can be sure the values are always equal or not if both ranges
// consist of a single value, and then compare them.
if (wi::eq_p (op1.lower_bound (), op1.upper_bound ())
&& wi::eq_p (op2.lower_bound (), op2.upper_bound ()))
{
if (wi::eq_p (op1.lower_bound (), op2.upper_bound()))
r = range_true (type);
else
r = range_false (type);
}
else
{
// If ranges do not intersect, we know the range is not equal,
// otherwise we don't know anything for sure.
int_range_max tmp = op1;
tmp.intersect (op2);
if (tmp.undefined_p ())
r = range_false (type);
else
r = range_true_and_false (type);
}
return true;
}
bool
operator_equal::op1_range (irange &r, tree type,
const irange &lhs,
const irange &op2,
relation_trio) const
{
switch (get_bool_state (r, lhs, type))
{
case BRS_TRUE:
// If it's true, the result is the same as OP2.
r = op2;
break;
case BRS_FALSE:
// If the result is false, the only time we know anything is
// if OP2 is a constant.
if (wi::eq_p (op2.lower_bound(), op2.upper_bound()))
{
r = op2;
r.invert ();
}
else
r.set_varying (type);
break;
default:
break;
}
return true;
}
bool
operator_equal::op2_range (irange &r, tree type,
const irange &lhs,
const irange &op1,
relation_trio rel) const
{
return operator_equal::op1_range (r, type, lhs, op1, rel.swap_op1_op2 ());
}
class operator_not_equal : public range_operator
{
using range_operator::fold_range;
using range_operator::op1_range;
using range_operator::op2_range;
public:
virtual bool fold_range (irange &r, tree type,
const irange &op1,
const irange &op2,
relation_trio = TRIO_VARYING) const;
virtual bool op1_range (irange &r, tree type,
const irange &lhs,
const irange &op2,
relation_trio = TRIO_VARYING) const;
virtual bool op2_range (irange &r, tree type,
const irange &lhs,
const irange &op1,
relation_trio = TRIO_VARYING) const;
virtual relation_kind op1_op2_relation (const irange &lhs) const;
} op_not_equal;
// Check if the LHS range indicates a relation between OP1 and OP2.
relation_kind
not_equal_op1_op2_relation (const irange &lhs)
{
if (lhs.undefined_p ())
return VREL_UNDEFINED;
// FALSE = op1 != op2 indicates EQ_EXPR.
if (lhs.zero_p ())
return VREL_EQ;
// TRUE = op1 != op2 indicates NE_EXPR.
if (!lhs.contains_p (build_zero_cst (lhs.type ())))
return VREL_NE;
return VREL_VARYING;
}
relation_kind
operator_not_equal::op1_op2_relation (const irange &lhs) const
{
return not_equal_op1_op2_relation (lhs);
}
bool
operator_not_equal::fold_range (irange &r, tree type,
const irange &op1,
const irange &op2,
relation_trio rel) const
{
if (relop_early_resolve (r, type, op1, op2, rel, VREL_NE))
return true;
// We can be sure the values are always equal or not if both ranges
// consist of a single value, and then compare them.
if (wi::eq_p (op1.lower_bound (), op1.upper_bound ())
&& wi::eq_p (op2.lower_bound (), op2.upper_bound ()))
{
if (wi::ne_p (op1.lower_bound (), op2.upper_bound()))
r = range_true (type);
else
r = range_false (type);
}
else
{
// If ranges do not intersect, we know the range is not equal,
// otherwise we don't know anything for sure.
int_range_max tmp = op1;
tmp.intersect (op2);
if (tmp.undefined_p ())
r = range_true (type);
else
r = range_true_and_false (type);
}
return true;
}
bool
operator_not_equal::op1_range (irange &r, tree type,
const irange &lhs,
const irange &op2,
relation_trio) const
{
switch (get_bool_state (r, lhs, type))
{
case BRS_TRUE:
// If the result is true, the only time we know anything is if
// OP2 is a constant.
if (wi::eq_p (op2.lower_bound(), op2.upper_bound()))
{
r = op2;
r.invert ();
}
else
r.set_varying (type);
break;
case BRS_FALSE:
// If it's false, the result is the same as OP2.
r = op2;
break;
default:
break;
}
return true;
}
bool
operator_not_equal::op2_range (irange &r, tree type,
const irange &lhs,
const irange &op1,
relation_trio rel) const
{
return operator_not_equal::op1_range (r, type, lhs, op1, rel.swap_op1_op2 ());
}
// (X < VAL) produces the range of [MIN, VAL - 1].
static void
build_lt (irange &r, tree type, const wide_int &val)
{
wi::overflow_type ov;
wide_int lim;
signop sgn = TYPE_SIGN (type);
// Signed 1 bit cannot represent 1 for subtraction.
if (sgn == SIGNED)
lim = wi::add (val, -1, sgn, &ov);
else
lim = wi::sub (val, 1, sgn, &ov);
// If val - 1 underflows, check if X < MIN, which is an empty range.
if (ov)
r.set_undefined ();
else
r = int_range<1> (type, min_limit (type), lim);
}
// (X <= VAL) produces the range of [MIN, VAL].
static void
build_le (irange &r, tree type, const wide_int &val)
{
r = int_range<1> (type, min_limit (type), val);
}
// (X > VAL) produces the range of [VAL + 1, MAX].
static void
build_gt (irange &r, tree type, const wide_int &val)
{
wi::overflow_type ov;
wide_int lim;
signop sgn = TYPE_SIGN (type);
// Signed 1 bit cannot represent 1 for addition.
if (sgn == SIGNED)
lim = wi::sub (val, -1, sgn, &ov);
else
lim = wi::add (val, 1, sgn, &ov);
// If val + 1 overflows, check is for X > MAX, which is an empty range.
if (ov)
r.set_undefined ();
else
r = int_range<1> (type, lim, max_limit (type));
}
// (X >= val) produces the range of [VAL, MAX].
static void
build_ge (irange &r, tree type, const wide_int &val)
{
r = int_range<1> (type, val, max_limit (type));
}
class operator_lt : public range_operator
{
using range_operator::fold_range;
using range_operator::op1_range;
using range_operator::op2_range;
public:
virtual bool fold_range (irange &r, tree type,
const irange &op1,
const irange &op2,
relation_trio = TRIO_VARYING) const;
virtual bool op1_range (irange &r, tree type,
const irange &lhs,
const irange &op2,
relation_trio = TRIO_VARYING) const;
virtual bool op2_range (irange &r, tree type,
const irange &lhs,
const irange &op1,
relation_trio = TRIO_VARYING) const;
virtual relation_kind op1_op2_relation (const irange &lhs) const;
} op_lt;
// Check if the LHS range indicates a relation between OP1 and OP2.
relation_kind
lt_op1_op2_relation (const irange &lhs)
{
if (lhs.undefined_p ())
return VREL_UNDEFINED;
// FALSE = op1 < op2 indicates GE_EXPR.
if (lhs.zero_p ())
return VREL_GE;
// TRUE = op1 < op2 indicates LT_EXPR.
if (!lhs.contains_p (build_zero_cst (lhs.type ())))
return VREL_LT;
return VREL_VARYING;
}
relation_kind
operator_lt::op1_op2_relation (const irange &lhs) const
{
return lt_op1_op2_relation (lhs);
}
bool
operator_lt::fold_range (irange &r, tree type,
const irange &op1,
const irange &op2,
relation_trio rel) const
{
if (relop_early_resolve (r, type, op1, op2, rel, VREL_LT))
return true;
signop sign = TYPE_SIGN (op1.type ());
gcc_checking_assert (sign == TYPE_SIGN (op2.type ()));
if (wi::lt_p (op1.upper_bound (), op2.lower_bound (), sign))
r = range_true (type);
else if (!wi::lt_p (op1.lower_bound (), op2.upper_bound (), sign))
r = range_false (type);
// Use nonzero bits to determine if < 0 is false.
else if (op2.zero_p () && !wi::neg_p (op1.get_nonzero_bits (), sign))
r = range_false (type);
else
r = range_true_and_false (type);
return true;
}
bool
operator_lt::op1_range (irange &r, tree type,
const irange &lhs,
const irange &op2,
relation_trio) const
{
switch (get_bool_state (r, lhs, type))
{
case BRS_TRUE:
build_lt (r, type, op2.upper_bound ());
break;
case BRS_FALSE:
build_ge (r, type, op2.lower_bound ());
break;
default:
break;
}
return true;
}
bool
operator_lt::op2_range (irange &r, tree type,
const irange &lhs,
const irange &op1,
relation_trio) const
{
switch (get_bool_state (r, lhs, type))
{
case BRS_TRUE:
build_gt (r, type, op1.lower_bound ());
break;
case BRS_FALSE:
build_le (r, type, op1.upper_bound ());
break;
default:
break;
}
return true;
}
class operator_le : public range_operator
{
using range_operator::fold_range;
using range_operator::op1_range;
using range_operator::op2_range;
public:
virtual bool fold_range (irange &r, tree type,
const irange &op1,
const irange &op2,
relation_trio = TRIO_VARYING) const;
virtual bool op1_range (irange &r, tree type,
const irange &lhs,
const irange &op2,
relation_trio = TRIO_VARYING) const;
virtual bool op2_range (irange &r, tree type,
const irange &lhs,
const irange &op1,
relation_trio = TRIO_VARYING) const;
virtual relation_kind op1_op2_relation (const irange &lhs) const;
} op_le;
// Check if the LHS range indicates a relation between OP1 and OP2.
relation_kind
le_op1_op2_relation (const irange &lhs)
{
if (lhs.undefined_p ())
return VREL_UNDEFINED;
// FALSE = op1 <= op2 indicates GT_EXPR.
if (lhs.zero_p ())
return VREL_GT;
// TRUE = op1 <= op2 indicates LE_EXPR.
if (!lhs.contains_p (build_zero_cst (lhs.type ())))
return VREL_LE;
return VREL_VARYING;
}
relation_kind
operator_le::op1_op2_relation (const irange &lhs) const
{
return le_op1_op2_relation (lhs);
}
bool
operator_le::fold_range (irange &r, tree type,
const irange &op1,
const irange &op2,
relation_trio rel) const
{
if (relop_early_resolve (r, type, op1, op2, rel, VREL_LE))
return true;
signop sign = TYPE_SIGN (op1.type ());
gcc_checking_assert (sign == TYPE_SIGN (op2.type ()));
if (wi::le_p (op1.upper_bound (), op2.lower_bound (), sign))
r = range_true (type);
else if (!wi::le_p (op1.lower_bound (), op2.upper_bound (), sign))
r = range_false (type);
else
r = range_true_and_false (type);
return true;
}
bool
operator_le::op1_range (irange &r, tree type,
const irange &lhs,
const irange &op2,
relation_trio) const
{
switch (get_bool_state (r, lhs, type))
{
case BRS_TRUE:
build_le (r, type, op2.upper_bound ());
break;
case BRS_FALSE:
build_gt (r, type, op2.lower_bound ());
break;
default:
break;
}
return true;
}
bool
operator_le::op2_range (irange &r, tree type,
const irange &lhs,
const irange &op1,
relation_trio) const
{
switch (get_bool_state (r, lhs, type))
{
case BRS_TRUE:
build_ge (r, type, op1.lower_bound ());
break;
case BRS_FALSE:
build_lt (r, type, op1.upper_bound ());
break;
default:
break;
}
return true;
}
class operator_gt : public range_operator
{
using range_operator::fold_range;
using range_operator::op1_range;
using range_operator::op2_range;
public:
virtual bool fold_range (irange &r, tree type,
const irange &op1,
const irange &op2,
relation_trio = TRIO_VARYING) const;
virtual bool op1_range (irange &r, tree type,
const irange &lhs,
const irange &op2,
relation_trio = TRIO_VARYING) const;
virtual bool op2_range (irange &r, tree type,
const irange &lhs,
const irange &op1,
relation_trio = TRIO_VARYING) const;
virtual relation_kind op1_op2_relation (const irange &lhs) const;
} op_gt;
// Check if the LHS range indicates a relation between OP1 and OP2.
relation_kind
gt_op1_op2_relation (const irange &lhs)
{
if (lhs.undefined_p ())
return VREL_UNDEFINED;
// FALSE = op1 > op2 indicates LE_EXPR.
if (lhs.zero_p ())
return VREL_LE;
// TRUE = op1 > op2 indicates GT_EXPR.
if (!lhs.contains_p (build_zero_cst (lhs.type ())))
return VREL_GT;
return VREL_VARYING;
}
relation_kind
operator_gt::op1_op2_relation (const irange &lhs) const
{
return gt_op1_op2_relation (lhs);
}
bool
operator_gt::fold_range (irange &r, tree type,
const irange &op1, const irange &op2,
relation_trio rel) const
{
if (relop_early_resolve (r, type, op1, op2, rel, VREL_GT))
return true;
signop sign = TYPE_SIGN (op1.type ());
gcc_checking_assert (sign == TYPE_SIGN (op2.type ()));
if (wi::gt_p (op1.lower_bound (), op2.upper_bound (), sign))
r = range_true (type);
else if (!wi::gt_p (op1.upper_bound (), op2.lower_bound (), sign))
r = range_false (type);
else
r = range_true_and_false (type);
return true;
}
bool
operator_gt::op1_range (irange &r, tree type,
const irange &lhs, const irange &op2,
relation_trio) const
{
switch (get_bool_state (r, lhs, type))
{
case BRS_TRUE:
build_gt (r, type, op2.lower_bound ());
break;
case BRS_FALSE:
build_le (r, type, op2.upper_bound ());
break;
default:
break;
}
return true;
}
bool
operator_gt::op2_range (irange &r, tree type,
const irange &lhs,
const irange &op1,
relation_trio) const
{
switch (get_bool_state (r, lhs, type))
{
case BRS_TRUE:
build_lt (r, type, op1.upper_bound ());
break;
case BRS_FALSE:
build_ge (r, type, op1.lower_bound ());
break;
default:
break;
}
return true;
}
class operator_ge : public range_operator
{
using range_operator::fold_range;
using range_operator::op1_range;
using range_operator::op2_range;
public:
virtual bool fold_range (irange &r, tree type,
const irange &op1,
const irange &op2,
relation_trio = TRIO_VARYING) const;
virtual bool op1_range (irange &r, tree type,
const irange &lhs,
const irange &op2,
relation_trio = TRIO_VARYING) const;
virtual bool op2_range (irange &r, tree type,
const irange &lhs,
const irange &op1,
relation_trio = TRIO_VARYING) const;
virtual relation_kind op1_op2_relation (const irange &lhs) const;
} op_ge;
// Check if the LHS range indicates a relation between OP1 and OP2.
relation_kind
ge_op1_op2_relation (const irange &lhs)
{
if (lhs.undefined_p ())
return VREL_UNDEFINED;
// FALSE = op1 >= op2 indicates LT_EXPR.
if (lhs.zero_p ())
return VREL_LT;
// TRUE = op1 >= op2 indicates GE_EXPR.
if (!lhs.contains_p (build_zero_cst (lhs.type ())))
return VREL_GE;
return VREL_VARYING;
}
relation_kind
operator_ge::op1_op2_relation (const irange &lhs) const
{
return ge_op1_op2_relation (lhs);
}
bool
operator_ge::fold_range (irange &r, tree type,
const irange &op1,
const irange &op2,
relation_trio rel) const
{
if (relop_early_resolve (r, type, op1, op2, rel, VREL_GE))
return true;
signop sign = TYPE_SIGN (op1.type ());
gcc_checking_assert (sign == TYPE_SIGN (op2.type ()));
if (wi::ge_p (op1.lower_bound (), op2.upper_bound (), sign))
r = range_true (type);
else if (!wi::ge_p (op1.upper_bound (), op2.lower_bound (), sign))
r = range_false (type);
else
r = range_true_and_false (type);
return true;
}
bool
operator_ge::op1_range (irange &r, tree type,
const irange &lhs,
const irange &op2,
relation_trio) const
{
switch (get_bool_state (r, lhs, type))
{
case BRS_TRUE:
build_ge (r, type, op2.lower_bound ());
break;
case BRS_FALSE:
build_lt (r, type, op2.upper_bound ());
break;
default:
break;
}
return true;
}
bool
operator_ge::op2_range (irange &r, tree type,
const irange &lhs,
const irange &op1,
relation_trio) const
{
switch (get_bool_state (r, lhs, type))
{
case BRS_TRUE:
build_le (r, type, op1.upper_bound ());
break;
case BRS_FALSE:
build_gt (r, type, op1.lower_bound ());
break;
default:
break;
}
return true;
}
class operator_plus : public range_operator
{
using range_operator::op1_range;
using range_operator::op2_range;
using range_operator::lhs_op1_relation;
using range_operator::lhs_op2_relation;
public:
virtual bool op1_range (irange &r, tree type,
const irange &lhs,
const irange &op2,
relation_trio) const;
virtual bool op2_range (irange &r, tree type,
const irange &lhs,
const irange &op1,
relation_trio) const;
virtual void wi_fold (irange &r, tree type,
const wide_int &lh_lb,
const wide_int &lh_ub,
const wide_int &rh_lb,
const wide_int &rh_ub) const;
virtual relation_kind lhs_op1_relation (const irange &lhs, const irange &op1,
const irange &op2,
relation_kind rel) const;
virtual relation_kind lhs_op2_relation (const irange &lhs, const irange &op1,
const irange &op2,
relation_kind rel) const;
} op_plus;
// Check to see if the range of OP2 indicates anything about the relation
// between LHS and OP1.
relation_kind
operator_plus::lhs_op1_relation (const irange &lhs,
const irange &op1,
const irange &op2,
relation_kind) const
{
if (lhs.undefined_p () || op1.undefined_p () || op2.undefined_p ())
return VREL_VARYING;
tree type = lhs.type ();
unsigned prec = TYPE_PRECISION (type);
wi::overflow_type ovf1, ovf2;
signop sign = TYPE_SIGN (type);
// LHS = OP1 + 0 indicates LHS == OP1.
if (op2.zero_p ())
return VREL_EQ;
if (TYPE_OVERFLOW_WRAPS (type))
{
wi::add (op1.lower_bound (), op2.lower_bound (), sign, &ovf1);
wi::add (op1.upper_bound (), op2.upper_bound (), sign, &ovf2);
}
else
ovf1 = ovf2 = wi::OVF_NONE;
// Never wrapping additions.
if (!ovf1 && !ovf2)
{
// Positive op2 means lhs > op1.
if (wi::gt_p (op2.lower_bound (), wi::zero (prec), sign))
return VREL_GT;
if (wi::ge_p (op2.lower_bound (), wi::zero (prec), sign))
return VREL_GE;
// Negative op2 means lhs < op1.
if (wi::lt_p (op2.upper_bound (), wi::zero (prec), sign))
return VREL_LT;
if (wi::le_p (op2.upper_bound (), wi::zero (prec), sign))
return VREL_LE;
}
// Always wrapping additions.
else if (ovf1 && ovf1 == ovf2)
{
// Positive op2 means lhs < op1.
if (wi::gt_p (op2.lower_bound (), wi::zero (prec), sign))
return VREL_LT;
if (wi::ge_p (op2.lower_bound (), wi::zero (prec), sign))
return VREL_LE;
// Negative op2 means lhs > op1.
if (wi::lt_p (op2.upper_bound (), wi::zero (prec), sign))
return VREL_GT;
if (wi::le_p (op2.upper_bound (), wi::zero (prec), sign))
return VREL_GE;
}
// If op2 does not contain 0, then LHS and OP1 can never be equal.
if (!range_includes_zero_p (&op2))
return VREL_NE;
return VREL_VARYING;
}
// PLUS is symmetrical, so we can simply call lhs_op1_relation with reversed
// operands.
relation_kind
operator_plus::lhs_op2_relation (const irange &lhs, const irange &op1,
const irange &op2, relation_kind rel) const
{
return lhs_op1_relation (lhs, op2, op1, rel);
}
void
operator_plus::wi_fold (irange &r, tree type,
const wide_int &lh_lb, const wide_int &lh_ub,
const wide_int &rh_lb, const wide_int &rh_ub) const
{
wi::overflow_type ov_lb, ov_ub;
signop s = TYPE_SIGN (type);
wide_int new_lb = wi::add (lh_lb, rh_lb, s, &ov_lb);
wide_int new_ub = wi::add (lh_ub, rh_ub, s, &ov_ub);
value_range_with_overflow (r, type, new_lb, new_ub, ov_lb, ov_ub);
}
// Given addition or subtraction, determine the possible NORMAL ranges and
// OVERFLOW ranges given an OFFSET range. ADD_P is true for addition.
// Return the relation that exists between the LHS and OP1 in order for the
// NORMAL range to apply.
// a return value of VREL_VARYING means no ranges were applicable.
static relation_kind
plus_minus_ranges (irange &r_ov, irange &r_normal, const irange &offset,
bool add_p)
{
relation_kind kind = VREL_VARYING;
// For now, only deal with constant adds. This could be extended to ranges
// when someone is so motivated.
if (!offset.singleton_p () || offset.zero_p ())
return kind;
// Always work with a positive offset. ie a+ -2 -> a-2 and a- -2 > a+2
wide_int off = offset.lower_bound ();
if (wi::neg_p (off, SIGNED))
{
add_p = !add_p;
off = wi::neg (off);
}
wi::overflow_type ov;
tree type = offset.type ();
unsigned prec = TYPE_PRECISION (type);
wide_int ub;
wide_int lb;
// calculate the normal range and relation for the operation.
if (add_p)
{
// [ 0 , INF - OFF]
lb = wi::zero (prec);
ub = wi::sub (wi::to_wide (vrp_val_max (type)), off, UNSIGNED, &ov);
kind = VREL_GT;
}
else
{
// [ OFF, INF ]
lb = off;
ub = wi::to_wide (vrp_val_max (type));
kind = VREL_LT;
}
int_range<2> normal_range (type, lb, ub);
int_range<2> ov_range (type, lb, ub, VR_ANTI_RANGE);
r_ov = ov_range;
r_normal = normal_range;
return kind;
}
// Once op1 has been calculated by operator_plus or operator_minus, check
// to see if the relation passed causes any part of the calculation to
// be not possible. ie
// a_2 = b_3 + 1 with a_2 < b_3 can refine the range of b_3 to [INF, INF]
// and that further refines a_2 to [0, 0].
// R is the value of op1, OP2 is the offset being added/subtracted, REL is the
// relation between LHS relatoin OP1 and ADD_P is true for PLUS, false for
// MINUS. IF any adjustment can be made, R will reflect it.
static void
adjust_op1_for_overflow (irange &r, const irange &op2, relation_kind rel,
bool add_p)
{
if (r.undefined_p ())
return;
tree type = r.type ();
// Check for unsigned overflow and calculate the overflow part.
signop s = TYPE_SIGN (type);
if (!TYPE_OVERFLOW_WRAPS (type) || s == SIGNED)
return;
// Only work with <, <=, >, >= relations.
if (!relation_lt_le_gt_ge_p (rel))
return;
// Get the ranges for this offset.
int_range_max normal, overflow;
relation_kind k = plus_minus_ranges (overflow, normal, op2, add_p);
// VREL_VARYING means there are no adjustments.
if (k == VREL_VARYING)
return;
// If the relations match use the normal range, otherwise use overflow range.
if (relation_intersect (k, rel) == k)
r.intersect (normal);
else
r.intersect (overflow);
return;
}
bool
operator_plus::op1_range (irange &r, tree type,
const irange &lhs,
const irange &op2,
relation_trio trio) const
{
if (lhs.undefined_p ())
return false;
// Start with the default operation.
range_op_handler minus (MINUS_EXPR, type);
if (!minus)
return false;
bool res = minus.fold_range (r, type, lhs, op2);
relation_kind rel = trio.lhs_op2 ();
// Check for a relation refinement.
if (res)
adjust_op1_for_overflow (r, op2, rel, true /* PLUS_EXPR */);
return res;
}
bool
operator_plus::op2_range (irange &r, tree type,
const irange &lhs,
const irange &op1,
relation_trio rel) const
{
return op1_range (r, type, lhs, op1, rel.swap_op1_op2 ());
}
class operator_minus : public range_operator
{
using range_operator::fold_range;
using range_operator::op1_range;
using range_operator::op2_range;
public:
virtual bool op1_range (irange &r, tree type,
const irange &lhs,
const irange &op2,
relation_trio) const;
virtual bool op2_range (irange &r, tree type,
const irange &lhs,
const irange &op1,
relation_trio) const;
virtual void wi_fold (irange &r, tree type,
const wide_int &lh_lb,
const wide_int &lh_ub,
const wide_int &rh_lb,
const wide_int &rh_ub) const;
virtual relation_kind lhs_op1_relation (const irange &lhs,
const irange &op1,
const irange &op2,
relation_kind rel) const;
virtual bool op1_op2_relation_effect (irange &lhs_range,
tree type,
const irange &op1_range,
const irange &op2_range,
relation_kind rel) const;
} op_minus;
void
operator_minus::wi_fold (irange &r, tree type,
const wide_int &lh_lb, const wide_int &lh_ub,
const wide_int &rh_lb, const wide_int &rh_ub) const
{
wi::overflow_type ov_lb, ov_ub;
signop s = TYPE_SIGN (type);
wide_int new_lb = wi::sub (lh_lb, rh_ub, s, &ov_lb);
wide_int new_ub = wi::sub (lh_ub, rh_lb, s, &ov_ub);
value_range_with_overflow (r, type, new_lb, new_ub, ov_lb, ov_ub);
}
// Return the relation between LHS and OP1 based on the relation between
// OP1 and OP2.
relation_kind
operator_minus::lhs_op1_relation (const irange &, const irange &op1,
const irange &, relation_kind rel) const
{
if (!op1.undefined_p () && TYPE_SIGN (op1.type ()) == UNSIGNED)
switch (rel)
{
case VREL_GT:
case VREL_GE:
return VREL_LE;
default:
break;
}
return VREL_VARYING;
}
// Check to see if the relation REL between OP1 and OP2 has any effect on the
// LHS of the expression. If so, apply it to LHS_RANGE. This is a helper
// function for both MINUS_EXPR and POINTER_DIFF_EXPR.
static bool
minus_op1_op2_relation_effect (irange &lhs_range, tree type,
const irange &op1_range ATTRIBUTE_UNUSED,
const irange &op2_range ATTRIBUTE_UNUSED,
relation_kind rel)
{
if (rel == VREL_VARYING)
return false;
int_range<2> rel_range;
unsigned prec = TYPE_PRECISION (type);
signop sgn = TYPE_SIGN (type);
// == and != produce [0,0] and ~[0,0] regardless of wrapping.
if (rel == VREL_EQ)
rel_range = int_range<2> (type, wi::zero (prec), wi::zero (prec));
else if (rel == VREL_NE)
rel_range = int_range<2> (type, wi::zero (prec), wi::zero (prec),
VR_ANTI_RANGE);
else if (TYPE_OVERFLOW_WRAPS (type))
{
switch (rel)
{
// For wrapping signed values and unsigned, if op1 > op2 or
// op1 < op2, then op1 - op2 can be restricted to ~[0, 0].
case VREL_GT:
case VREL_LT:
rel_range = int_range<2> (type, wi::zero (prec), wi::zero (prec),
VR_ANTI_RANGE);
break;
default:
return false;
}
}
else
{
switch (rel)
{
// op1 > op2, op1 - op2 can be restricted to [1, +INF]
case VREL_GT:
rel_range = int_range<2> (type, wi::one (prec),
wi::max_value (prec, sgn));
break;
// op1 >= op2, op1 - op2 can be restricted to [0, +INF]
case VREL_GE:
rel_range = int_range<2> (type, wi::zero (prec),
wi::max_value (prec, sgn));
break;
// op1 < op2, op1 - op2 can be restricted to [-INF, -1]
case VREL_LT:
rel_range = int_range<2> (type, wi::min_value (prec, sgn),
wi::minus_one (prec));
break;
// op1 <= op2, op1 - op2 can be restricted to [-INF, 0]
case VREL_LE:
rel_range = int_range<2> (type, wi::min_value (prec, sgn),
wi::zero (prec));
break;
default:
return false;
}
}
lhs_range.intersect (rel_range);
return true;
}
bool
operator_minus::op1_op2_relation_effect (irange &lhs_range, tree type,
const irange &op1_range,
const irange &op2_range,
relation_kind rel) const
{
return minus_op1_op2_relation_effect (lhs_range, type, op1_range, op2_range,
rel);
}
bool
operator_minus::op1_range (irange &r, tree type,
const irange &lhs,
const irange &op2,
relation_trio trio) const
{
if (lhs.undefined_p ())
return false;
// Start with the default operation.
range_op_handler minus (PLUS_EXPR, type);
if (!minus)
return false;
bool res = minus.fold_range (r, type, lhs, op2);
relation_kind rel = trio.lhs_op2 ();
if (res)
adjust_op1_for_overflow (r, op2, rel, false /* PLUS_EXPR */);
return res;
}
bool
operator_minus::op2_range (irange &r, tree type,
const irange &lhs,
const irange &op1,
relation_trio) const
{
if (lhs.undefined_p ())
return false;
return fold_range (r, type, op1, lhs);
}
class operator_pointer_diff : public range_operator
{
virtual bool op1_op2_relation_effect (irange &lhs_range,
tree type,
const irange &op1_range,
const irange &op2_range,
relation_kind rel) const;
} op_pointer_diff;
bool
operator_pointer_diff::op1_op2_relation_effect (irange &lhs_range, tree type,
const irange &op1_range,
const irange &op2_range,
relation_kind rel) const
{
return minus_op1_op2_relation_effect (lhs_range, type, op1_range, op2_range,
rel);
}
class operator_min : public range_operator
{
public:
virtual void wi_fold (irange &r, tree type,
const wide_int &lh_lb,
const wide_int &lh_ub,
const wide_int &rh_lb,
const wide_int &rh_ub) const;
} op_min;
void
operator_min::wi_fold (irange &r, tree type,
const wide_int &lh_lb, const wide_int &lh_ub,
const wide_int &rh_lb, const wide_int &rh_ub) const
{
signop s = TYPE_SIGN (type);
wide_int new_lb = wi::min (lh_lb, rh_lb, s);
wide_int new_ub = wi::min (lh_ub, rh_ub, s);
value_range_with_overflow (r, type, new_lb, new_ub);
}
class operator_max : public range_operator
{
public:
virtual void wi_fold (irange &r, tree type,
const wide_int &lh_lb,
const wide_int &lh_ub,
const wide_int &rh_lb,
const wide_int &rh_ub) const;
} op_max;
void
operator_max::wi_fold (irange &r, tree type,
const wide_int &lh_lb, const wide_int &lh_ub,
const wide_int &rh_lb, const wide_int &rh_ub) const
{
signop s = TYPE_SIGN (type);
wide_int new_lb = wi::max (lh_lb, rh_lb, s);
wide_int new_ub = wi::max (lh_ub, rh_ub, s);
value_range_with_overflow (r, type, new_lb, new_ub);
}
class cross_product_operator : public range_operator
{
public:
// Perform an operation between two wide-ints and place the result
// in R. Return true if the operation overflowed.
virtual bool wi_op_overflows (wide_int &r,
tree type,
const wide_int &,
const wide_int &) const = 0;
// Calculate the cross product of two sets of sub-ranges and return it.
void wi_cross_product (irange &r, tree type,
const wide_int &lh_lb,
const wide_int &lh_ub,
const wide_int &rh_lb,
const wide_int &rh_ub) const;
};
// Calculate the cross product of two sets of ranges and return it.
//
// Multiplications, divisions and shifts are a bit tricky to handle,
// depending on the mix of signs we have in the two ranges, we need to
// operate on different values to get the minimum and maximum values
// for the new range. One approach is to figure out all the
// variations of range combinations and do the operations.
//
// However, this involves several calls to compare_values and it is
// pretty convoluted. It's simpler to do the 4 operations (MIN0 OP
// MIN1, MIN0 OP MAX1, MAX0 OP MIN1 and MAX0 OP MAX0 OP MAX1) and then
// figure the smallest and largest values to form the new range.
void
cross_product_operator::wi_cross_product (irange &r, tree type,
const wide_int &lh_lb,
const wide_int &lh_ub,
const wide_int &rh_lb,
const wide_int &rh_ub) const
{
wide_int cp1, cp2, cp3, cp4;
// Default to varying.
r.set_varying (type);
// Compute the 4 cross operations, bailing if we get an overflow we
// can't handle.
if (wi_op_overflows (cp1, type, lh_lb, rh_lb))
return;
if (wi::eq_p (lh_lb, lh_ub))
cp3 = cp1;
else if (wi_op_overflows (cp3, type, lh_ub, rh_lb))
return;
if (wi::eq_p (rh_lb, rh_ub))
cp2 = cp1;
else if (wi_op_overflows (cp2, type, lh_lb, rh_ub))
return;
if (wi::eq_p (lh_lb, lh_ub))
cp4 = cp2;
else if (wi_op_overflows (cp4, type, lh_ub, rh_ub))
return;
// Order pairs.
signop sign = TYPE_SIGN (type);
if (wi::gt_p (cp1, cp2, sign))
std::swap (cp1, cp2);
if (wi::gt_p (cp3, cp4, sign))
std::swap (cp3, cp4);
// Choose min and max from the ordered pairs.
wide_int res_lb = wi::min (cp1, cp3, sign);
wide_int res_ub = wi::max (cp2, cp4, sign);
value_range_with_overflow (r, type, res_lb, res_ub);
}
class operator_mult : public cross_product_operator
{
using range_operator::op1_range;
using range_operator::op2_range;
public:
virtual void wi_fold (irange &r, tree type,
const wide_int &lh_lb,
const wide_int &lh_ub,
const wide_int &rh_lb,
const wide_int &rh_ub) const final override;
virtual bool wi_op_overflows (wide_int &res, tree type,
const wide_int &w0, const wide_int &w1)
const final override;
virtual bool op1_range (irange &r, tree type,
const irange &lhs,
const irange &op2,
relation_trio) const final override;
virtual bool op2_range (irange &r, tree type,
const irange &lhs,
const irange &op1,
relation_trio) const final override;
} op_mult;
bool
operator_mult::op1_range (irange &r, tree type,
const irange &lhs, const irange &op2,
relation_trio) const
{
tree offset;
if (lhs.undefined_p ())
return false;
// We can't solve 0 = OP1 * N by dividing by N with a wrapping type.
// For example: For 0 = OP1 * 2, OP1 could be 0, or MAXINT, whereas
// for 4 = OP1 * 2, OP1 could be 2 or 130 (unsigned 8-bit)
if (TYPE_OVERFLOW_WRAPS (type))
return false;
if (op2.singleton_p (&offset) && !integer_zerop (offset))
return range_op_handler (TRUNC_DIV_EXPR, type).fold_range (r, type,
lhs, op2);
return false;
}
bool
operator_mult::op2_range (irange &r, tree type,
const irange &lhs, const irange &op1,
relation_trio rel) const
{
return operator_mult::op1_range (r, type, lhs, op1, rel.swap_op1_op2 ());
}
bool
operator_mult::wi_op_overflows (wide_int &res, tree type,
const wide_int &w0, const wide_int &w1) const
{
wi::overflow_type overflow = wi::OVF_NONE;
signop sign = TYPE_SIGN (type);
res = wi::mul (w0, w1, sign, &overflow);
if (overflow && TYPE_OVERFLOW_UNDEFINED (type))
{
// For multiplication, the sign of the overflow is given
// by the comparison of the signs of the operands.
if (sign == UNSIGNED || w0.sign_mask () == w1.sign_mask ())
res = wi::max_value (w0.get_precision (), sign);
else
res = wi::min_value (w0.get_precision (), sign);
return false;
}
return overflow;
}
void
operator_mult::wi_fold (irange &r, tree type,
const wide_int &lh_lb, const wide_int &lh_ub,
const wide_int &rh_lb, const wide_int &rh_ub) const
{
if (TYPE_OVERFLOW_UNDEFINED (type))
{
wi_cross_product (r, type, lh_lb, lh_ub, rh_lb, rh_ub);
return;
}
// Multiply the ranges when overflow wraps. This is basically fancy
// code so we don't drop to varying with an unsigned
// [-3,-1]*[-3,-1].
//
// This test requires 2*prec bits if both operands are signed and
// 2*prec + 2 bits if either is not. Therefore, extend the values
// using the sign of the result to PREC2. From here on out,
// everthing is just signed math no matter what the input types
// were.
signop sign = TYPE_SIGN (type);
unsigned prec = TYPE_PRECISION (type);
widest2_int min0 = widest2_int::from (lh_lb, sign);
widest2_int max0 = widest2_int::from (lh_ub, sign);
widest2_int min1 = widest2_int::from (rh_lb, sign);
widest2_int max1 = widest2_int::from (rh_ub, sign);
widest2_int sizem1 = wi::mask <widest2_int> (prec, false);
widest2_int size = sizem1 + 1;
// Canonicalize the intervals.
if (sign == UNSIGNED)
{
if (wi::ltu_p (size, min0 + max0))
{
min0 -= size;
max0 -= size;
}
if (wi::ltu_p (size, min1 + max1))
{
min1 -= size;
max1 -= size;
}
}
// Sort the 4 products so that min is in prod0 and max is in
// prod3.
widest2_int prod0 = min0 * min1;
widest2_int prod1 = min0 * max1;
widest2_int prod2 = max0 * min1;
widest2_int prod3 = max0 * max1;
// min0min1 > max0max1
if (prod0 > prod3)
std::swap (prod0, prod3);
// min0max1 > max0min1
if (prod1 > prod2)
std::swap (prod1, prod2);
if (prod0 > prod1)
std::swap (prod0, prod1);
if (prod2 > prod3)
std::swap (prod2, prod3);
// diff = max - min
prod2 = prod3 - prod0;
if (wi::geu_p (prod2, sizem1))
{
// Multiplying by X, where X is a power of 2 is [0,0][X,+INF].
if (TYPE_UNSIGNED (type) && rh_lb == rh_ub
&& wi::exact_log2 (rh_lb) != -1 && prec > 1)
{
r.set (type, rh_lb, wi::max_value (prec, sign));
int_range<2> zero;
zero.set_zero (type);
r.union_ (zero);
}
else
// The range covers all values.
r.set_varying (type);
}
else
{
wide_int new_lb = wide_int::from (prod0, prec, sign);
wide_int new_ub = wide_int::from (prod3, prec, sign);
create_possibly_reversed_range (r, type, new_lb, new_ub);
}
}
class operator_div : public cross_product_operator
{
public:
virtual void wi_fold (irange &r, tree type,
const wide_int &lh_lb,
const wide_int &lh_ub,
const wide_int &rh_lb,
const wide_int &rh_ub) const final override;
virtual bool wi_op_overflows (wide_int &res, tree type,
const wide_int &, const wide_int &)
const final override;
};
bool
operator_div::wi_op_overflows (wide_int &res, tree type,
const wide_int &w0, const wide_int &w1) const
{
if (w1 == 0)
return true;
wi::overflow_type overflow = wi::OVF_NONE;
signop sign = TYPE_SIGN (type);
switch (m_code)
{
case EXACT_DIV_EXPR:
case TRUNC_DIV_EXPR:
res = wi::div_trunc (w0, w1, sign, &overflow);
break;
case FLOOR_DIV_EXPR:
res = wi::div_floor (w0, w1, sign, &overflow);
break;
case ROUND_DIV_EXPR:
res = wi::div_round (w0, w1, sign, &overflow);
break;
case CEIL_DIV_EXPR:
res = wi::div_ceil (w0, w1, sign, &overflow);
break;
default:
gcc_unreachable ();
}
if (overflow && TYPE_OVERFLOW_UNDEFINED (type))
{
// For division, the only case is -INF / -1 = +INF.
res = wi::max_value (w0.get_precision (), sign);
return false;
}
return overflow;
}
void
operator_div::wi_fold (irange &r, tree type,
const wide_int &lh_lb, const wide_int &lh_ub,
const wide_int &rh_lb, const wide_int &rh_ub) const
{
const wide_int dividend_min = lh_lb;
const wide_int dividend_max = lh_ub;
const wide_int divisor_min = rh_lb;
const wide_int divisor_max = rh_ub;
signop sign = TYPE_SIGN (type);
unsigned prec = TYPE_PRECISION (type);
wide_int extra_min, extra_max;
// If we know we won't divide by zero, just do the division.
if (!wi_includes_zero_p (type, divisor_min, divisor_max))
{
wi_cross_product (r, type, dividend_min, dividend_max,
divisor_min, divisor_max);
return;
}
// If we're definitely dividing by zero, there's nothing to do.
if (wi_zero_p (type, divisor_min, divisor_max))
{
r.set_undefined ();
return;
}
// Perform the division in 2 parts, [LB, -1] and [1, UB], which will
// skip any division by zero.
// First divide by the negative numbers, if any.
if (wi::neg_p (divisor_min, sign))
wi_cross_product (r, type, dividend_min, dividend_max,
divisor_min, wi::minus_one (prec));
else
r.set_undefined ();
// Then divide by the non-zero positive numbers, if any.
if (wi::gt_p (divisor_max, wi::zero (prec), sign))
{
int_range_max tmp;
wi_cross_product (tmp, type, dividend_min, dividend_max,
wi::one (prec), divisor_max);
r.union_ (tmp);
}
// We shouldn't still have undefined here.
gcc_checking_assert (!r.undefined_p ());
}
class operator_exact_divide : public operator_div
{
using range_operator::op1_range;
public:
virtual bool op1_range (irange &r, tree type,
const irange &lhs,
const irange &op2,
relation_trio) const;
} op_exact_div;
bool
operator_exact_divide::op1_range (irange &r, tree type,
const irange &lhs,
const irange &op2,
relation_trio) const
{
if (lhs.undefined_p ())
return false;
tree offset;
// [2, 4] = op1 / [3,3] since its exact divide, no need to worry about
// remainders in the endpoints, so op1 = [2,4] * [3,3] = [6,12].
// We wont bother trying to enumerate all the in between stuff :-P
// TRUE accuraacy is [6,6][9,9][12,12]. This is unlikely to matter most of
// the time however.
// If op2 is a multiple of 2, we would be able to set some non-zero bits.
if (op2.singleton_p (&offset)
&& !integer_zerop (offset))
return range_op_handler (MULT_EXPR, type).fold_range (r, type, lhs, op2);
return false;
}
class operator_lshift : public cross_product_operator
{
using range_operator::fold_range;
using range_operator::op1_range;
public:
virtual bool op1_range (irange &r, tree type,
const irange &lhs,
const irange &op2,
relation_trio rel = TRIO_VARYING) const;
virtual bool fold_range (irange &r, tree type,
const irange &op1,
const irange &op2,
relation_trio rel = TRIO_VARYING) const;
virtual void wi_fold (irange &r, tree type,
const wide_int &lh_lb, const wide_int &lh_ub,
const wide_int &rh_lb, const wide_int &rh_ub) const;
virtual bool wi_op_overflows (wide_int &res,
tree type,
const wide_int &,
const wide_int &) const;
} op_lshift;
class operator_rshift : public cross_product_operator
{
using range_operator::fold_range;
using range_operator::op1_range;
using range_operator::lhs_op1_relation;
public:
virtual bool fold_range (irange &r, tree type,
const irange &op1,
const irange &op2,
relation_trio rel = TRIO_VARYING) const;
virtual void wi_fold (irange &r, tree type,
const wide_int &lh_lb,
const wide_int &lh_ub,
const wide_int &rh_lb,
const wide_int &rh_ub) const;
virtual bool wi_op_overflows (wide_int &res,
tree type,
const wide_int &w0,
const wide_int &w1) const;
virtual bool op1_range (irange &, tree type,
const irange &lhs,
const irange &op2,
relation_trio rel = TRIO_VARYING) const;
virtual relation_kind lhs_op1_relation (const irange &lhs,
const irange &op1,
const irange &op2,
relation_kind rel) const;
} op_rshift;
relation_kind
operator_rshift::lhs_op1_relation (const irange &lhs ATTRIBUTE_UNUSED,
const irange &op1,
const irange &op2,
relation_kind) const
{
// If both operands range are >= 0, then the LHS <= op1.
if (!op1.undefined_p () && !op2.undefined_p ()
&& wi::ge_p (op1.lower_bound (), 0, TYPE_SIGN (op1.type ()))
&& wi::ge_p (op2.lower_bound (), 0, TYPE_SIGN (op2.type ())))
return VREL_LE;
return VREL_VARYING;
}
bool
operator_lshift::fold_range (irange &r, tree type,
const irange &op1,
const irange &op2,
relation_trio rel) const
{
int_range_max shift_range;
if (!get_shift_range (shift_range, type, op2))
{
if (op2.undefined_p ())
r.set_undefined ();
else
r.set_varying (type);
return true;
}
// Transform left shifts by constants into multiplies.
if (shift_range.singleton_p ())
{
unsigned shift = shift_range.lower_bound ().to_uhwi ();
wide_int tmp = wi::set_bit_in_zero (shift, TYPE_PRECISION (type));
int_range<1> mult (type, tmp, tmp);
// Force wrapping multiplication.
bool saved_flag_wrapv = flag_wrapv;
bool saved_flag_wrapv_pointer = flag_wrapv_pointer;
flag_wrapv = 1;
flag_wrapv_pointer = 1;
bool b = op_mult.fold_range (r, type, op1, mult);
flag_wrapv = saved_flag_wrapv;
flag_wrapv_pointer = saved_flag_wrapv_pointer;
return b;
}
else
// Otherwise, invoke the generic fold routine.
return range_operator::fold_range (r, type, op1, shift_range, rel);
}
void
operator_lshift::wi_fold (irange &r, tree type,
const wide_int &lh_lb, const wide_int &lh_ub,
const wide_int &rh_lb, const wide_int &rh_ub) const
{
signop sign = TYPE_SIGN (type);
unsigned prec = TYPE_PRECISION (type);
int overflow_pos = sign == SIGNED ? prec - 1 : prec;
int bound_shift = overflow_pos - rh_ub.to_shwi ();
// If bound_shift == HOST_BITS_PER_WIDE_INT, the llshift can
// overflow. However, for that to happen, rh.max needs to be zero,
// which means rh is a singleton range of zero, which means we simply return
// [lh_lb, lh_ub] as the range.
if (wi::eq_p (rh_ub, rh_lb) && wi::eq_p (rh_ub, 0))
{
r = int_range<2> (type, lh_lb, lh_ub);
return;
}
wide_int bound = wi::set_bit_in_zero (bound_shift, prec);
wide_int complement = ~(bound - 1);
wide_int low_bound, high_bound;
bool in_bounds = false;
if (sign == UNSIGNED)
{
low_bound = bound;
high_bound = complement;
if (wi::ltu_p (lh_ub, low_bound))
{
// [5, 6] << [1, 2] == [10, 24].
// We're shifting out only zeroes, the value increases
// monotonically.
in_bounds = true;
}
else if (wi::ltu_p (high_bound, lh_lb))
{
// [0xffffff00, 0xffffffff] << [1, 2]
// == [0xfffffc00, 0xfffffffe].
// We're shifting out only ones, the value decreases
// monotonically.
in_bounds = true;
}
}
else
{
// [-1, 1] << [1, 2] == [-4, 4]
low_bound = complement;
high_bound = bound;
if (wi::lts_p (lh_ub, high_bound)
&& wi::lts_p (low_bound, lh_lb))
{
// For non-negative numbers, we're shifting out only zeroes,
// the value increases monotonically. For negative numbers,
// we're shifting out only ones, the value decreases
// monotonically.
in_bounds = true;
}
}
if (in_bounds)
wi_cross_product (r, type, lh_lb, lh_ub, rh_lb, rh_ub);
else
r.set_varying (type);
}
bool
operator_lshift::wi_op_overflows (wide_int &res, tree type,
const wide_int &w0, const wide_int &w1) const
{
signop sign = TYPE_SIGN (type);
if (wi::neg_p (w1))
{
// It's unclear from the C standard whether shifts can overflow.
// The following code ignores overflow; perhaps a C standard
// interpretation ruling is needed.
res = wi::rshift (w0, -w1, sign);
}
else
res = wi::lshift (w0, w1);
return false;
}
bool
operator_lshift::op1_range (irange &r,
tree type,
const irange &lhs,
const irange &op2,
relation_trio) const
{
if (lhs.undefined_p ())
return false;
tree shift_amount;
if (!lhs.contains_p (build_zero_cst (type)))
r.set_nonzero (type);
else
r.set_varying (type);
if (op2.singleton_p (&shift_amount))
{
wide_int shift = wi::to_wide (shift_amount);
if (wi::lt_p (shift, 0, SIGNED))
return false;
if (wi::ge_p (shift, wi::uhwi (TYPE_PRECISION (type),
TYPE_PRECISION (op2.type ())),
UNSIGNED))
return false;
if (shift == 0)
{
r.intersect (lhs);
return true;
}
// Work completely in unsigned mode to start.
tree utype = type;
int_range_max tmp_range;
if (TYPE_SIGN (type) == SIGNED)
{
int_range_max tmp = lhs;
utype = unsigned_type_for (type);
range_cast (tmp, utype);
op_rshift.fold_range (tmp_range, utype, tmp, op2);
}
else
op_rshift.fold_range (tmp_range, utype, lhs, op2);
// Start with ranges which can produce the LHS by right shifting the
// result by the shift amount.
// ie [0x08, 0xF0] = op1 << 2 will start with
// [00001000, 11110000] = op1 << 2
// [0x02, 0x4C] aka [00000010, 00111100]
// Then create a range from the LB with the least significant upper bit
// set, to the upper bound with all the bits set.
// This would be [0x42, 0xFC] aka [01000010, 11111100].
// Ideally we do this for each subrange, but just lump them all for now.
unsigned low_bits = TYPE_PRECISION (utype)
- TREE_INT_CST_LOW (shift_amount);
wide_int up_mask = wi::mask (low_bits, true, TYPE_PRECISION (utype));
wide_int new_ub = wi::bit_or (up_mask, tmp_range.upper_bound ());
wide_int new_lb = wi::set_bit (tmp_range.lower_bound (), low_bits);
int_range<2> fill_range (utype, new_lb, new_ub);
tmp_range.union_ (fill_range);
if (utype != type)
range_cast (tmp_range, type);
r.intersect (tmp_range);
return true;
}
return !r.varying_p ();
}
bool
operator_rshift::op1_range (irange &r,
tree type,
const irange &lhs,
const irange &op2,
relation_trio) const
{
tree shift;
if (lhs.undefined_p ())
return false;
if (op2.singleton_p (&shift))
{
// Ignore nonsensical shifts.
unsigned prec = TYPE_PRECISION (type);
if (wi::ge_p (wi::to_wide (shift),
wi::uhwi (prec, TYPE_PRECISION (TREE_TYPE (shift))),
UNSIGNED))
return false;
if (wi::to_wide (shift) == 0)
{
r = lhs;
return true;
}
// Folding the original operation may discard some impossible
// ranges from the LHS.
int_range_max lhs_refined;
op_rshift.fold_range (lhs_refined, type, int_range<1> (type), op2);
lhs_refined.intersect (lhs);
if (lhs_refined.undefined_p ())
{
r.set_undefined ();
return true;
}
int_range_max shift_range (shift, shift);
int_range_max lb, ub;
op_lshift.fold_range (lb, type, lhs_refined, shift_range);
// LHS
// 0000 0111 = OP1 >> 3
//
// OP1 is anything from 0011 1000 to 0011 1111. That is, a
// range from LHS<<3 plus a mask of the 3 bits we shifted on the
// right hand side (0x07).
tree mask = fold_build1 (BIT_NOT_EXPR, type,
fold_build2 (LSHIFT_EXPR, type,
build_minus_one_cst (type),
shift));
int_range_max mask_range (build_zero_cst (type), mask);
op_plus.fold_range (ub, type, lb, mask_range);
r = lb;
r.union_ (ub);
if (!lhs_refined.contains_p (build_zero_cst (type)))
{
mask_range.invert ();
r.intersect (mask_range);
}
return true;
}
return false;
}
bool
operator_rshift::wi_op_overflows (wide_int &res,
tree type,
const wide_int &w0,
const wide_int &w1) const
{
signop sign = TYPE_SIGN (type);
if (wi::neg_p (w1))
res = wi::lshift (w0, -w1);
else
{
// It's unclear from the C standard whether shifts can overflow.
// The following code ignores overflow; perhaps a C standard
// interpretation ruling is needed.
res = wi::rshift (w0, w1, sign);
}
return false;
}
bool
operator_rshift::fold_range (irange &r, tree type,
const irange &op1,
const irange &op2,
relation_trio rel) const
{
int_range_max shift;
if (!get_shift_range (shift, type, op2))
{
if (op2.undefined_p ())
r.set_undefined ();
else
r.set_varying (type);
return true;
}
return range_operator::fold_range (r, type, op1, shift, rel);
}
void
operator_rshift::wi_fold (irange &r, tree type,
const wide_int &lh_lb, const wide_int &lh_ub,
const wide_int &rh_lb, const wide_int &rh_ub) const
{
wi_cross_product (r, type, lh_lb, lh_ub, rh_lb, rh_ub);
}
class operator_cast: public range_operator
{
using range_operator::fold_range;
using range_operator::op1_range;
public:
virtual bool fold_range (irange &r, tree type,
const irange &op1,
const irange &op2,
relation_trio rel = TRIO_VARYING) const;
virtual bool op1_range (irange &r, tree type,
const irange &lhs,
const irange &op2,
relation_trio rel = TRIO_VARYING) const;
virtual relation_kind lhs_op1_relation (const irange &lhs,
const irange &op1,
const irange &op2,
relation_kind) const;
private:
bool truncating_cast_p (const irange &inner, const irange &outer) const;
bool inside_domain_p (const wide_int &min, const wide_int &max,
const irange &outer) const;
void fold_pair (irange &r, unsigned index, const irange &inner,
const irange &outer) const;
};
// Add a partial equivalence between the LHS and op1 for casts.
relation_kind
operator_cast::lhs_op1_relation (const irange &lhs,
const irange &op1,
const irange &op2 ATTRIBUTE_UNUSED,
relation_kind) const
{
if (lhs.undefined_p () || op1.undefined_p ())
return VREL_VARYING;
unsigned lhs_prec = TYPE_PRECISION (lhs.type ());
unsigned op1_prec = TYPE_PRECISION (op1.type ());
// If the result gets sign extended into a larger type check first if this
// qualifies as a partial equivalence.
if (TYPE_SIGN (op1.type ()) == SIGNED && lhs_prec > op1_prec)
{
// If the result is sign extended, and the LHS is larger than op1,
// check if op1's range can be negative as the sign extention will
// cause the upper bits to be 1 instead of 0, invalidating the PE.
int_range<3> negs = range_negatives (op1.type ());
negs.intersect (op1);
if (!negs.undefined_p ())
return VREL_VARYING;
}
unsigned prec = MIN (lhs_prec, op1_prec);
return bits_to_pe (prec);
}
// Return TRUE if casting from INNER to OUTER is a truncating cast.
inline bool
operator_cast::truncating_cast_p (const irange &inner,
const irange &outer) const
{
return TYPE_PRECISION (outer.type ()) < TYPE_PRECISION (inner.type ());
}
// Return TRUE if [MIN,MAX] is inside the domain of RANGE's type.
bool
operator_cast::inside_domain_p (const wide_int &min,
const wide_int &max,
const irange &range) const
{
wide_int domain_min = wi::to_wide (vrp_val_min (range.type ()));
wide_int domain_max = wi::to_wide (vrp_val_max (range.type ()));
signop domain_sign = TYPE_SIGN (range.type ());
return (wi::le_p (min, domain_max, domain_sign)
&& wi::le_p (max, domain_max, domain_sign)
&& wi::ge_p (min, domain_min, domain_sign)
&& wi::ge_p (max, domain_min, domain_sign));
}
// Helper for fold_range which work on a pair at a time.
void
operator_cast::fold_pair (irange &r, unsigned index,
const irange &inner,
const irange &outer) const
{
tree inner_type = inner.type ();
tree outer_type = outer.type ();
signop inner_sign = TYPE_SIGN (inner_type);
unsigned outer_prec = TYPE_PRECISION (outer_type);
// check to see if casting from INNER to OUTER is a conversion that
// fits in the resulting OUTER type.
wide_int inner_lb = inner.lower_bound (index);
wide_int inner_ub = inner.upper_bound (index);
if (truncating_cast_p (inner, outer))
{
// We may be able to accomodate a truncating cast if the
// resulting range can be represented in the target type...
if (wi::rshift (wi::sub (inner_ub, inner_lb),
wi::uhwi (outer_prec, TYPE_PRECISION (inner.type ())),
inner_sign) != 0)
{
r.set_varying (outer_type);
return;
}
}
// ...but we must still verify that the final range fits in the
// domain. This catches -fstrict-enum restrictions where the domain
// range is smaller than what fits in the underlying type.
wide_int min = wide_int::from (inner_lb, outer_prec, inner_sign);
wide_int max = wide_int::from (inner_ub, outer_prec, inner_sign);
if (inside_domain_p (min, max, outer))
create_possibly_reversed_range (r, outer_type, min, max);
else
r.set_varying (outer_type);
}
bool
operator_cast::fold_range (irange &r, tree type ATTRIBUTE_UNUSED,
const irange &inner,
const irange &outer,
relation_trio) const
{
if (empty_range_varying (r, type, inner, outer))
return true;
gcc_checking_assert (outer.varying_p ());
gcc_checking_assert (inner.num_pairs () > 0);
// Avoid a temporary by folding the first pair directly into the result.
fold_pair (r, 0, inner, outer);
// Then process any additonal pairs by unioning with their results.
for (unsigned x = 1; x < inner.num_pairs (); ++x)
{
int_range_max tmp;
fold_pair (tmp, x, inner, outer);
r.union_ (tmp);
if (r.varying_p ())
return true;
}
// Update the nonzero mask. Truncating casts are problematic unless
// the conversion fits in the resulting outer type.
wide_int nz = inner.get_nonzero_bits ();
if (truncating_cast_p (inner, outer)
&& wi::rshift (nz, wi::uhwi (TYPE_PRECISION (outer.type ()),
TYPE_PRECISION (inner.type ())),
TYPE_SIGN (inner.type ())) != 0)
return true;
nz = wide_int::from (nz, TYPE_PRECISION (type), TYPE_SIGN (inner.type ()));
r.set_nonzero_bits (nz);
return true;
}
bool
operator_cast::op1_range (irange &r, tree type,
const irange &lhs,
const irange &op2,
relation_trio) const
{
if (lhs.undefined_p ())
return false;
tree lhs_type = lhs.type ();
gcc_checking_assert (types_compatible_p (op2.type(), type));
// If we are calculating a pointer, shortcut to what we really care about.
if (POINTER_TYPE_P (type))
{
// Conversion from other pointers or a constant (including 0/NULL)
// are straightforward.
if (POINTER_TYPE_P (lhs.type ())
|| (lhs.singleton_p ()
&& TYPE_PRECISION (lhs.type ()) >= TYPE_PRECISION (type)))
{
r = lhs;
range_cast (r, type);
}
else
{
// If the LHS is not a pointer nor a singleton, then it is
// either VARYING or non-zero.
if (!lhs.contains_p (build_zero_cst (lhs.type ())))
r.set_nonzero (type);
else
r.set_varying (type);
}
r.intersect (op2);
return true;
}
if (truncating_cast_p (op2, lhs))
{
if (lhs.varying_p ())
r.set_varying (type);
else
{
// We want to insert the LHS as an unsigned value since it
// would not trigger the signed bit of the larger type.
int_range_max converted_lhs = lhs;
range_cast (converted_lhs, unsigned_type_for (lhs_type));
range_cast (converted_lhs, type);
// Start by building the positive signed outer range for the type.
wide_int lim = wi::set_bit_in_zero (TYPE_PRECISION (lhs_type),
TYPE_PRECISION (type));
r = int_range<1> (type, lim, wi::max_value (TYPE_PRECISION (type),
SIGNED));
// For the signed part, we need to simply union the 2 ranges now.
r.union_ (converted_lhs);
// Create maximal negative number outside of LHS bits.
lim = wi::mask (TYPE_PRECISION (lhs_type), true,
TYPE_PRECISION (type));
// Add this to the unsigned LHS range(s).
int_range_max lim_range (type, lim, lim);
int_range_max lhs_neg;
range_op_handler (PLUS_EXPR, type).fold_range (lhs_neg, type,
converted_lhs,
lim_range);
// lhs_neg now has all the negative versions of the LHS.
// Now union in all the values from SIGNED MIN (0x80000) to
// lim-1 in order to fill in all the ranges with the upper
// bits set.
// PR 97317. If the lhs has only 1 bit less precision than the rhs,
// we don't need to create a range from min to lim-1
// calculate neg range traps trying to create [lim, lim - 1].
wide_int min_val = wi::min_value (TYPE_PRECISION (type), SIGNED);
if (lim != min_val)
{
int_range_max neg (type,
wi::min_value (TYPE_PRECISION (type),
SIGNED),
lim - 1);
lhs_neg.union_ (neg);
}
// And finally, munge the signed and unsigned portions.
r.union_ (lhs_neg);
}
// And intersect with any known value passed in the extra operand.
r.intersect (op2);
return true;
}
int_range_max tmp;
if (TYPE_PRECISION (lhs_type) == TYPE_PRECISION (type))
tmp = lhs;
else
{
// The cast is not truncating, and the range is restricted to
// the range of the RHS by this assignment.
//
// Cast the range of the RHS to the type of the LHS.
fold_range (tmp, lhs_type, int_range<1> (type), int_range<1> (lhs_type));
// Intersect this with the LHS range will produce the range,
// which will be cast to the RHS type before returning.
tmp.intersect (lhs);
}
// Cast the calculated range to the type of the RHS.
fold_range (r, type, tmp, int_range<1> (type));
return true;
}
class operator_logical_and : public range_operator
{
using range_operator::fold_range;
using range_operator::op1_range;
using range_operator::op2_range;
public:
virtual bool fold_range (irange &r, tree type,
const irange &lh,
const irange &rh,
relation_trio rel = TRIO_VARYING) const;
virtual bool op1_range (irange &r, tree type,
const irange &lhs,
const irange &op2,
relation_trio rel = TRIO_VARYING) const;
virtual bool op2_range (irange &r, tree type,
const irange &lhs,
const irange &op1,
relation_trio rel = TRIO_VARYING) const;
} op_logical_and;
bool
operator_logical_and::fold_range (irange &r, tree type,
const irange &lh,
const irange &rh,
relation_trio) const
{
if (empty_range_varying (r, type, lh, rh))
return true;
// 0 && anything is 0.
if ((wi::eq_p (lh.lower_bound (), 0) && wi::eq_p (lh.upper_bound (), 0))
|| (wi::eq_p (lh.lower_bound (), 0) && wi::eq_p (rh.upper_bound (), 0)))
r = range_false (type);
else if (lh.contains_p (build_zero_cst (lh.type ()))
|| rh.contains_p (build_zero_cst (rh.type ())))
// To reach this point, there must be a logical 1 on each side, and
// the only remaining question is whether there is a zero or not.
r = range_true_and_false (type);
else
r = range_true (type);
return true;
}
bool
operator_logical_and::op1_range (irange &r, tree type,
const irange &lhs,
const irange &op2 ATTRIBUTE_UNUSED,
relation_trio) const
{
switch (get_bool_state (r, lhs, type))
{
case BRS_TRUE:
// A true result means both sides of the AND must be true.
r = range_true (type);
break;
default:
// Any other result means only one side has to be false, the
// other side can be anything. So we cannot be sure of any
// result here.
r = range_true_and_false (type);
break;
}
return true;
}
bool
operator_logical_and::op2_range (irange &r, tree type,
const irange &lhs,
const irange &op1,
relation_trio) const
{
return operator_logical_and::op1_range (r, type, lhs, op1);
}
class operator_bitwise_and : public range_operator
{
using range_operator::op1_range;
using range_operator::op2_range;
public:
virtual bool op1_range (irange &r, tree type,
const irange &lhs,
const irange &op2,
relation_trio rel = TRIO_VARYING) const;
virtual bool op2_range (irange &r, tree type,
const irange &lhs,
const irange &op1,
relation_trio rel = TRIO_VARYING) const;
virtual void wi_fold (irange &r, tree type,
const wide_int &lh_lb,
const wide_int &lh_ub,
const wide_int &rh_lb,
const wide_int &rh_ub) const;
virtual relation_kind lhs_op1_relation (const irange &lhs,
const irange &op1,
const irange &op2,
relation_kind) const;
private:
void simple_op1_range_solver (irange &r, tree type,
const irange &lhs,
const irange &op2) const;
} op_bitwise_and;
// Optimize BIT_AND_EXPR, BIT_IOR_EXPR and BIT_XOR_EXPR of signed types
// by considering the number of leading redundant sign bit copies.
// clrsb (X op Y) = min (clrsb (X), clrsb (Y)), so for example
// [-1, 0] op [-1, 0] is [-1, 0] (where nonzero_bits doesn't help).
static bool
wi_optimize_signed_bitwise_op (irange &r, tree type,
const wide_int &lh_lb, const wide_int &lh_ub,
const wide_int &rh_lb, const wide_int &rh_ub)
{
int lh_clrsb = MIN (wi::clrsb (lh_lb), wi::clrsb (lh_ub));
int rh_clrsb = MIN (wi::clrsb (rh_lb), wi::clrsb (rh_ub));
int new_clrsb = MIN (lh_clrsb, rh_clrsb);
if (new_clrsb == 0)
return false;
int type_prec = TYPE_PRECISION (type);
int rprec = (type_prec - new_clrsb) - 1;
value_range_with_overflow (r, type,
wi::mask (rprec, true, type_prec),
wi::mask (rprec, false, type_prec));
return true;
}
// An AND of 8,16, 32 or 64 bits can produce a partial equivalence between
// the LHS and op1.
relation_kind
operator_bitwise_and::lhs_op1_relation (const irange &lhs,
const irange &op1,
const irange &op2,
relation_kind) const
{
if (lhs.undefined_p () || op1.undefined_p () || op2.undefined_p ())
return VREL_VARYING;
if (!op2.singleton_p ())
return VREL_VARYING;
// if val == 0xff or 0xFFFF OR 0Xffffffff OR 0Xffffffffffffffff, return TRUE
int prec1 = TYPE_PRECISION (op1.type ());
int prec2 = TYPE_PRECISION (op2.type ());
int mask_prec = 0;
wide_int mask = op2.lower_bound ();
if (wi::eq_p (mask, wi::mask (8, false, prec2)))
mask_prec = 8;
else if (wi::eq_p (mask, wi::mask (16, false, prec2)))
mask_prec = 16;
else if (wi::eq_p (mask, wi::mask (32, false, prec2)))
mask_prec = 32;
else if (wi::eq_p (mask, wi::mask (64, false, prec2)))
mask_prec = 64;
return bits_to_pe (MIN (prec1, mask_prec));
}
// Optimize BIT_AND_EXPR and BIT_IOR_EXPR in terms of a mask if
// possible. Basically, see if we can optimize:
//
// [LB, UB] op Z
// into:
// [LB op Z, UB op Z]
//
// If the optimization was successful, accumulate the range in R and
// return TRUE.
static bool
wi_optimize_and_or (irange &r,
enum tree_code code,
tree type,
const wide_int &lh_lb, const wide_int &lh_ub,
const wide_int &rh_lb, const wide_int &rh_ub)
{
// Calculate the singleton mask among the ranges, if any.
wide_int lower_bound, upper_bound, mask;
if (wi::eq_p (rh_lb, rh_ub))
{
mask = rh_lb;
lower_bound = lh_lb;
upper_bound = lh_ub;
}
else if (wi::eq_p (lh_lb, lh_ub))
{
mask = lh_lb;
lower_bound = rh_lb;
upper_bound = rh_ub;
}
else
return false;
// If Z is a constant which (for op | its bitwise not) has n
// consecutive least significant bits cleared followed by m 1
// consecutive bits set immediately above it and either
// m + n == precision, or (x >> (m + n)) == (y >> (m + n)).
//
// The least significant n bits of all the values in the range are
// cleared or set, the m bits above it are preserved and any bits
// above these are required to be the same for all values in the
// range.
wide_int w = mask;
int m = 0, n = 0;
if (code == BIT_IOR_EXPR)
w = ~w;
if (wi::eq_p (w, 0))
n = w.get_precision ();
else
{
n = wi::ctz (w);
w = ~(w | wi::mask (n, false, w.get_precision ()));
if (wi::eq_p (w, 0))
m = w.get_precision () - n;
else
m = wi::ctz (w) - n;
}
wide_int new_mask = wi::mask (m + n, true, w.get_precision ());
if ((new_mask & lower_bound) != (new_mask & upper_bound))
return false;
wide_int res_lb, res_ub;
if (code == BIT_AND_EXPR)
{
res_lb = wi::bit_and (lower_bound, mask);
res_ub = wi::bit_and (upper_bound, mask);
}
else if (code == BIT_IOR_EXPR)
{
res_lb = wi::bit_or (lower_bound, mask);
res_ub = wi::bit_or (upper_bound, mask);
}
else
gcc_unreachable ();
value_range_with_overflow (r, type, res_lb, res_ub);
// Furthermore, if the mask is non-zero, an IOR cannot contain zero.
if (code == BIT_IOR_EXPR && wi::ne_p (mask, 0))
{
int_range<2> tmp;
tmp.set_nonzero (type);
r.intersect (tmp);
}
return true;
}
// For range [LB, UB] compute two wide_int bit masks.
//
// In the MAYBE_NONZERO bit mask, if some bit is unset, it means that
// for all numbers in the range the bit is 0, otherwise it might be 0
// or 1.
//
// In the MUSTBE_NONZERO bit mask, if some bit is set, it means that
// for all numbers in the range the bit is 1, otherwise it might be 0
// or 1.
void
wi_set_zero_nonzero_bits (tree type,
const wide_int &lb, const wide_int &ub,
wide_int &maybe_nonzero,
wide_int &mustbe_nonzero)
{
signop sign = TYPE_SIGN (type);
if (wi::eq_p (lb, ub))
maybe_nonzero = mustbe_nonzero = lb;
else if (wi::ge_p (lb, 0, sign) || wi::lt_p (ub, 0, sign))
{
wide_int xor_mask = lb ^ ub;
maybe_nonzero = lb | ub;
mustbe_nonzero = lb & ub;
if (xor_mask != 0)
{
wide_int mask = wi::mask (wi::floor_log2 (xor_mask), false,
maybe_nonzero.get_precision ());
maybe_nonzero = maybe_nonzero | mask;
mustbe_nonzero = wi::bit_and_not (mustbe_nonzero, mask);
}
}
else
{
maybe_nonzero = wi::minus_one (lb.get_precision ());
mustbe_nonzero = wi::zero (lb.get_precision ());
}
}
void
operator_bitwise_and::wi_fold (irange &r, tree type,
const wide_int &lh_lb,
const wide_int &lh_ub,
const wide_int &rh_lb,
const wide_int &rh_ub) const
{
if (wi_optimize_and_or (r, BIT_AND_EXPR, type, lh_lb, lh_ub, rh_lb, rh_ub))
return;
wide_int maybe_nonzero_lh, mustbe_nonzero_lh;
wide_int maybe_nonzero_rh, mustbe_nonzero_rh;
wi_set_zero_nonzero_bits (type, lh_lb, lh_ub,
maybe_nonzero_lh, mustbe_nonzero_lh);
wi_set_zero_nonzero_bits (type, rh_lb, rh_ub,
maybe_nonzero_rh, mustbe_nonzero_rh);
wide_int new_lb = mustbe_nonzero_lh & mustbe_nonzero_rh;
wide_int new_ub = maybe_nonzero_lh & maybe_nonzero_rh;
signop sign = TYPE_SIGN (type);
unsigned prec = TYPE_PRECISION (type);
// If both input ranges contain only negative values, we can
// truncate the result range maximum to the minimum of the
// input range maxima.
if (wi::lt_p (lh_ub, 0, sign) && wi::lt_p (rh_ub, 0, sign))
{
new_ub = wi::min (new_ub, lh_ub, sign);
new_ub = wi::min (new_ub, rh_ub, sign);
}
// If either input range contains only non-negative values
// we can truncate the result range maximum to the respective
// maximum of the input range.
if (wi::ge_p (lh_lb, 0, sign))
new_ub = wi::min (new_ub, lh_ub, sign);
if (wi::ge_p (rh_lb, 0, sign))
new_ub = wi::min (new_ub, rh_ub, sign);
// PR68217: In case of signed & sign-bit-CST should
// result in [-INF, 0] instead of [-INF, INF].