1/* Header file for range operator class. 2 Copyright (C) 2017-2020 Free Software Foundation, Inc. 3 Contributed by Andrew MacLeod <amacleod@redhat.com> 4 and Aldy Hernandez <aldyh@redhat.com>. 5 6This file is part of GCC. 7 8GCC is free software; you can redistribute it and/or modify it under 9the terms of the GNU General Public License as published by the Free 10Software Foundation; either version 3, or (at your option) any later 11version. 12 13GCC is distributed in the hope that it will be useful, but WITHOUT ANY 14WARRANTY; without even the implied warranty of MERCHANTABILITY or 15FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 16 for more details. 17 18You should have received a copy of the GNU General Public License 19along with GCC; see the file COPYING3. If not see 20<http://www.gnu.org/licenses/>. */ 21 22#ifndef GCC_RANGE_OP_H 23#define GCC_RANGE_OP_H 24 25// This class is implemented for each kind of operator supported by 26// the range generator. It serves various purposes. 27// 28// 1 - Generates range information for the specific operation between 29// two ranges. This provides the ability to fold ranges for an 30// expression. 31// 32// 2 - Performs range algebra on the expression such that a range can be 33// adjusted in terms of one of the operands: 34// 35// def = op1 + op2 36// 37// Given a range for def, we can adjust the range so that it is in 38// terms of either operand. 39// 40// op1_range (def_range, op2) will adjust the range in place so it 41// is in terms of op1. Since op1 = def - op2, it will subtract 42// op2 from each element of the range. 43// 44// 3 - Creates a range for an operand based on whether the result is 0 or 45// non-zero. This is mostly for logical true false, but can serve other 46// purposes. 47// ie 0 = op1 - op2 implies op2 has the same range as op1. 48 49class range_operator 50{ 51public: 52 // Perform an operation between 2 ranges and return it. 53 virtual bool fold_range (value_range &r, tree type, 54 const value_range &lh, 55 const value_range &rh) const; 56 57 // Return the range for op[12] in the general case. LHS is the range for 58 // the LHS of the expression, OP[12]is the range for the other 59 // 60 // The operand and the result is returned in R. 61 // 62 // TYPE is the expected type of the range. 63 // 64 // Return TRUE if the operation is performed and a valid range is available. 65 // 66 // i.e. [LHS] = ??? + OP2 67 // is re-formed as R = [LHS] - OP2. 68 virtual bool op1_range (value_range &r, tree type, 69 const value_range &lhs, 70 const value_range &op2) const; 71 virtual bool op2_range (value_range &r, tree type, 72 const value_range &lhs, 73 const value_range &op1) const; 74 75protected: 76 // Perform an integral operation between 2 sub-ranges and return it. 77 virtual void wi_fold (value_range &r, tree type, 78 const wide_int &lh_lb, 79 const wide_int &lh_ub, 80 const wide_int &rh_lb, 81 const wide_int &rh_ub) const; 82}; 83 84extern range_operator *range_op_handler (enum tree_code code, tree type); 85extern void range_cast (value_range &, tree type); 86extern void wi_set_zero_nonzero_bits (tree type, 87 const wide_int &, const wide_int &, 88 wide_int &maybe_nonzero, 89 wide_int &mustbe_nonzero); 90 91#endif // GCC_RANGE_OP_H 92