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/* Header file for range operator class.
Copyright (C) 2017-2020 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/>. */
#ifndef GCC_RANGE_OP_H
#define GCC_RANGE_OP_H
// This class is implemented for each kind of operator supported by
// the range generator. It serves various purposes.
//
// 1 - Generates range information for the specific operation between
// two ranges. This provides the ability to fold ranges for an
// expression.
//
// 2 - Performs range algebra on the expression such that a range can be
// adjusted in terms of one of the operands:
//
// def = op1 + op2
//
// Given a range for def, we can adjust the range so that it is in
// terms of either operand.
//
// op1_range (def_range, op2) will adjust the range in place so it
// is in terms of op1. Since op1 = def - op2, it will subtract
// op2 from each element of the range.
//
// 3 - Creates a range for an operand based on whether the result is 0 or
// non-zero. This is mostly for logical true false, but can serve other
// purposes.
// ie 0 = op1 - op2 implies op2 has the same range as op1.
class range_operator
{
public:
// Perform an operation between 2 ranges and return it.
virtual bool fold_range (irange &r, tree type,
const irange &lh,
const irange &rh) const;
// Return the range for op[12] in the general case. LHS is the range for
// the LHS of the expression, OP[12]is the range for the other
//
// The operand and the result is returned in R.
//
// TYPE is the expected type of the range.
//
// Return TRUE if the operation is performed and a valid range is available.
//
// i.e. [LHS] = ??? + OP2
// is re-formed as R = [LHS] - OP2.
virtual bool op1_range (irange &r, tree type,
const irange &lhs,
const irange &op2) const;
virtual bool op2_range (irange &r, tree type,
const irange &lhs,
const irange &op1) const;
protected:
// Perform an integral operation between 2 sub-ranges and return it.
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;
};
extern range_operator *range_op_handler (enum tree_code code, tree type);
extern void range_cast (irange &, tree type);
extern void wi_set_zero_nonzero_bits (tree type,
const wide_int &, const wide_int &,
wide_int &maybe_nonzero,
wide_int &mustbe_nonzero);
#endif // GCC_RANGE_OP_H
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