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 /* Header file for range operator class. Copyright (C) 2017-2021 Free Software Foundation, Inc. Contributed by Andrew MacLeod and Aldy Hernandez . 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 . */ #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, relation_kind rel = VREL_NONE) 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, relation_kind rel = VREL_NONE) const; virtual bool op2_range (irange &r, tree type, const irange &lhs, const irange &op1, relation_kind rel = VREL_NONE) const; // The following routines are used to represent relations between the // various operations. If the caller knows where the symbolics are, // it can query for relationships between them given known ranges. virtual enum tree_code lhs_op1_relation (const irange &lhs, const irange &op1, const irange &op2) const; virtual enum tree_code lhs_op2_relation (const irange &lhs, const irange &op1, const irange &op2) const; virtual enum tree_code op1_op2_relation (const irange &lhs) 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; // Side effect of relation for generic fold_range clients. virtual bool op1_op2_relation_effect (irange &lhs_range, tree type, const irange &op1_range, const irange &op2_range, relation_kind rel) const; // Called by fold range to split small subranges into parts. void 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; }; 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