319 lines
10 KiB
C++
319 lines
10 KiB
C++
/* Header file for range operator class.
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Copyright (C) 2017-2023 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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friend class range_op_table;
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public:
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range_operator () : m_code (ERROR_MARK) { }
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// Perform an operation between 2 ranges and return it.
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virtual bool fold_range (irange &r, tree type,
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const irange &lh,
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const irange &rh,
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relation_trio = TRIO_VARYING) 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 (irange &r, tree type,
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const irange &lhs,
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const irange &op2,
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relation_trio = TRIO_VARYING) const;
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virtual bool op2_range (irange &r, tree type,
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const irange &lhs,
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const irange &op1,
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relation_trio = TRIO_VARYING) const;
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// The following routines are used to represent relations between the
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// various operations. If the caller knows where the symbolics are,
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// it can query for relationships between them given known ranges.
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// the optional relation passed in is the relation between op1 and op2.
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virtual relation_kind lhs_op1_relation (const irange &lhs,
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const irange &op1,
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const irange &op2,
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relation_kind = VREL_VARYING) const;
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virtual relation_kind lhs_op2_relation (const irange &lhs,
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const irange &op1,
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const irange &op2,
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relation_kind = VREL_VARYING) const;
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virtual relation_kind op1_op2_relation (const irange &lhs) 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 (irange &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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// Effect of relation for generic fold_range clients.
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virtual bool op1_op2_relation_effect (irange &lhs_range, tree type,
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const irange &op1_range,
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const irange &op2_range,
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relation_kind rel) const;
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// Called by fold range to split small subranges into parts.
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void wi_fold_in_parts (irange &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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// Called by fold range to split small subranges into parts when op1 == op2
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void wi_fold_in_parts_equiv (irange &r, tree type,
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const wide_int &lb,
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const wide_int &ub,
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unsigned limit) const;
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// Tree code of the range operator or ERROR_MARK if unknown.
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tree_code m_code;
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};
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// Like range_operator above, but for floating point operators.
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class range_operator_float
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{
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public:
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virtual bool fold_range (frange &r, tree type,
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const frange &lh,
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const frange &rh,
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relation_trio = TRIO_VARYING) const;
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virtual void rv_fold (REAL_VALUE_TYPE &lb, REAL_VALUE_TYPE &ub,
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bool &maybe_nan,
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tree type,
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const REAL_VALUE_TYPE &lh_lb,
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const REAL_VALUE_TYPE &lh_ub,
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const REAL_VALUE_TYPE &rh_lb,
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const REAL_VALUE_TYPE &rh_ub,
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relation_kind) const;
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// Unary operations have the range of the LHS as op2.
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virtual bool fold_range (irange &r, tree type,
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const frange &lh,
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const irange &rh,
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relation_trio = TRIO_VARYING) const;
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virtual bool fold_range (irange &r, tree type,
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const frange &lh,
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const frange &rh,
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relation_trio = TRIO_VARYING) const;
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virtual bool op1_range (frange &r, tree type,
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const frange &lhs,
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const frange &op2,
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relation_trio = TRIO_VARYING) const;
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virtual bool op1_range (frange &r, tree type,
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const irange &lhs,
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const frange &op2,
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relation_trio = TRIO_VARYING) const;
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virtual bool op2_range (frange &r, tree type,
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const frange &lhs,
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const frange &op1,
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relation_trio = TRIO_VARYING) const;
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virtual bool op2_range (frange &r, tree type,
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const irange &lhs,
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const frange &op1,
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relation_trio = TRIO_VARYING) const;
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virtual relation_kind lhs_op1_relation (const frange &lhs,
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const frange &op1,
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const frange &op2,
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relation_kind = VREL_VARYING) const;
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virtual relation_kind lhs_op1_relation (const irange &lhs,
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const frange &op1,
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const frange &op2,
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relation_kind = VREL_VARYING) const;
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virtual relation_kind lhs_op2_relation (const frange &lhs,
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const frange &op1,
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const frange &op2,
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relation_kind = VREL_VARYING) const;
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virtual relation_kind lhs_op2_relation (const irange &lhs,
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const frange &op1,
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const frange &op2,
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relation_kind = VREL_VARYING) const;
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virtual relation_kind op1_op2_relation (const irange &lhs) const;
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virtual relation_kind op1_op2_relation (const frange &lhs) const;
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};
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class range_op_handler
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{
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public:
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range_op_handler ();
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range_op_handler (enum tree_code code, tree type);
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inline operator bool () const { return m_valid; }
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bool fold_range (vrange &r, tree type,
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const vrange &lh,
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const vrange &rh,
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relation_trio = TRIO_VARYING) const;
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bool op1_range (vrange &r, tree type,
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const vrange &lhs,
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const vrange &op2,
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relation_trio = TRIO_VARYING) const;
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bool op2_range (vrange &r, tree type,
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const vrange &lhs,
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const vrange &op1,
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relation_trio = TRIO_VARYING) const;
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relation_kind lhs_op1_relation (const vrange &lhs,
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const vrange &op1,
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const vrange &op2,
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relation_kind = VREL_VARYING) const;
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relation_kind lhs_op2_relation (const vrange &lhs,
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const vrange &op1,
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const vrange &op2,
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relation_kind = VREL_VARYING) const;
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relation_kind op1_op2_relation (const vrange &lhs) const;
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protected:
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void set_op_handler (enum tree_code code, tree type);
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bool m_valid;
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range_operator *m_int;
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range_operator_float *m_float;
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};
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extern bool range_cast (vrange &, 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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// op1_op2_relation methods that are the same across irange and frange.
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relation_kind equal_op1_op2_relation (const irange &lhs);
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relation_kind not_equal_op1_op2_relation (const irange &lhs);
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relation_kind lt_op1_op2_relation (const irange &lhs);
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relation_kind le_op1_op2_relation (const irange &lhs);
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relation_kind gt_op1_op2_relation (const irange &lhs);
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relation_kind ge_op1_op2_relation (const irange &lhs);
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enum bool_range_state { BRS_FALSE, BRS_TRUE, BRS_EMPTY, BRS_FULL };
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bool_range_state get_bool_state (vrange &r, const vrange &lhs, tree val_type);
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// If the range of either op1 or op2 is undefined, set the result to
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// varying and return TRUE. If the caller truly cares about a result,
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// they should pass in a varying if it has an undefined that it wants
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// treated as a varying.
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inline bool
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empty_range_varying (vrange &r, tree type,
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const vrange &op1, const vrange & op2)
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{
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if (op1.undefined_p () || op2.undefined_p ())
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{
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r.set_varying (type);
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return true;
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}
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else
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return false;
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}
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// For relation opcodes, first try to see if the supplied relation
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// forces a true or false result, and return that.
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// Then check for undefined operands. If none of this applies,
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// return false.
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inline bool
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relop_early_resolve (irange &r, tree type, const vrange &op1,
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const vrange &op2, relation_trio trio,
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relation_kind my_rel)
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{
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relation_kind rel = trio.op1_op2 ();
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// If known relation is a complete subset of this relation, always true.
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if (relation_union (rel, my_rel) == my_rel)
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{
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r = range_true (type);
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return true;
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}
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// If known relation has no subset of this relation, always false.
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if (relation_intersect (rel, my_rel) == VREL_UNDEFINED)
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{
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r = range_false (type);
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return true;
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}
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// If either operand is undefined, return VARYING.
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if (empty_range_varying (r, type, op1, op2))
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return true;
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return false;
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}
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// This implements the range operator tables as local objects.
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class range_op_table
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{
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public:
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range_operator *operator[] (enum tree_code code);
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protected:
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void set (enum tree_code code, range_operator &op);
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private:
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range_operator *m_range_tree[MAX_TREE_CODES];
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};
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// Like above, but for floating point operators.
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class floating_op_table
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{
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public:
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floating_op_table ();
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range_operator_float *operator[] (enum tree_code code);
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private:
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void set (enum tree_code code, range_operator_float &op);
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range_operator_float *m_range_tree[MAX_TREE_CODES];
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};
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// This holds the range op table for floating point operations.
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extern floating_op_table *floating_tree_table;
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extern range_operator *ptr_op_widen_mult_signed;
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extern range_operator *ptr_op_widen_mult_unsigned;
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extern range_operator *ptr_op_widen_plus_signed;
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extern range_operator *ptr_op_widen_plus_unsigned;
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#endif // GCC_RANGE_OP_H
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