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 6 This file is part of GCC. 7 8 GCC is free software; you can redistribute it and/or modify it under 9 the terms of the GNU General Public License as published by the Free 10 Software Foundation; either version 3, or (at your option) any later 11 version. 12 13 GCC is distributed in the hope that it will be useful, but WITHOUT ANY 14 WARRANTY; without even the implied warranty of MERCHANTABILITY or 15 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 16 for more details. 17 18 You should have received a copy of the GNU General Public License 19 along 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 49 class range_operator 50 { 51 public: 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 75 protected: 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 84 extern range_operator *range_op_handler (enum tree_code code, tree type); 85 extern void range_cast (value_range &, tree type); 86 extern 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