92 lines
3.2 KiB
C++
92 lines
3.2 KiB
C++
/* Header file for range operator class.
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Copyright (C) 2017-2020 Free Software Foundation, Inc.
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Contributed by Andrew MacLeod <amacleod@redhat.com>
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and Aldy Hernandez <aldyh@redhat.com>.
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This file is part of GCC.
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GCC is free software; you can redistribute it and/or modify it under
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the terms of the GNU General Public License as published by the Free
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Software Foundation; either version 3, or (at your option) any later
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version.
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GCC is distributed in the hope that it will be useful, but WITHOUT ANY
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WARRANTY; without even the implied warranty of MERCHANTABILITY or
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FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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for more details.
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You should have received a copy of the GNU General Public License
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along with GCC; see the file COPYING3. If not see
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<http://www.gnu.org/licenses/>. */
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#ifndef GCC_RANGE_OP_H
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#define GCC_RANGE_OP_H
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// This class is implemented for each kind of operator supported by
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// the range generator. It serves various purposes.
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//
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// 1 - Generates range information for the specific operation between
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// two ranges. This provides the ability to fold ranges for an
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// expression.
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//
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// 2 - Performs range algebra on the expression such that a range can be
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// adjusted in terms of one of the operands:
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//
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// def = op1 + op2
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//
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// Given a range for def, we can adjust the range so that it is in
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// terms of either operand.
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//
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// op1_range (def_range, op2) will adjust the range in place so it
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// is in terms of op1. Since op1 = def - op2, it will subtract
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// op2 from each element of the range.
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//
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// 3 - Creates a range for an operand based on whether the result is 0 or
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// non-zero. This is mostly for logical true false, but can serve other
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// purposes.
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// ie 0 = op1 - op2 implies op2 has the same range as op1.
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class range_operator
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{
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public:
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// Perform an operation between 2 ranges and return it.
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virtual bool fold_range (value_range &r, tree type,
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const value_range &lh,
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const value_range &rh) const;
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// Return the range for op[12] in the general case. LHS is the range for
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// the LHS of the expression, OP[12]is the range for the other
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//
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// The operand and the result is returned in R.
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//
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// TYPE is the expected type of the range.
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//
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// Return TRUE if the operation is performed and a valid range is available.
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//
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// i.e. [LHS] = ??? + OP2
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// is re-formed as R = [LHS] - OP2.
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virtual bool op1_range (value_range &r, tree type,
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const value_range &lhs,
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const value_range &op2) const;
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virtual bool op2_range (value_range &r, tree type,
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const value_range &lhs,
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const value_range &op1) const;
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protected:
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// Perform an integral operation between 2 sub-ranges and return it.
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virtual void wi_fold (value_range &r, tree type,
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const wide_int &lh_lb,
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const wide_int &lh_ub,
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const wide_int &rh_lb,
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const wide_int &rh_ub) const;
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};
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extern range_operator *range_op_handler (enum tree_code code, tree type);
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extern void range_cast (value_range &, tree type);
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extern void wi_set_zero_nonzero_bits (tree type,
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const wide_int &, const wide_int &,
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wide_int &maybe_nonzero,
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wide_int &mustbe_nonzero);
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#endif // GCC_RANGE_OP_H
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