/* * Licensed to the Apache Software Foundation (ASF) under one * or more contributor license agreements. See the NOTICE file * distributed with this work for additional information * regarding copyright ownership. The ASF licenses this file * to you under the Apache License, Version 2.0 (the * "License"); you may not use this file except in compliance * with the License. You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, * software distributed under the License is distributed on an * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY * KIND, either express or implied. See the License for the * specific language governing permissions and limitations * under the License. */ /*! * Copyright (c) 2019 by Contributors * \file int_op_overflow.h * \brief Utility functions to detect if an integer op will overflow. */ #ifndef TVM_ARITHMETIC_INT_OP_OVERFLOW_H_ #define TVM_ARITHMETIC_INT_OP_OVERFLOW_H_ #include <limits> namespace tvm { namespace arith { /*! * \brief Check if an integer op with operand x, y will overflow. * \param x The left operand. * \param y The left operand. * \param min_value The minimum value of the domain. * \param max_value The maximum value of the domain. * \return Whether overflow can happen. * \tparam Op The integer operator. */ template<typename Op> inline bool WillOverflow(int64_t x, int64_t y, int64_t min_value, int64_t max_value) { return false; } template<> bool WillOverflow<ir::Add>(int64_t x, int64_t y, int64_t min_value, int64_t max_value) { if ((y > 0) && (x > max_value - y)) return true; if ((y < 0) && (x < min_value - y)) return true; return false; } template<> bool WillOverflow<ir::Sub>(int64_t x, int64_t y, int64_t min_value, int64_t max_value) { if ((y > 0) && (x < min_value + y)) return true; if ((y < 0) && (x > max_value + y)) return true; return false; } template<> bool WillOverflow<ir::Mul>(int64_t x, int64_t y, int64_t min_value, int64_t max_value) { if (y == 0) return false; if (y > 0) { if (x < min_value / y) return true; if (x > max_value / y) return true; } else { if (y == -1 && x == std::numeric_limits<int64_t>::min()) return true; if (x > min_value / y) return true; if (x < max_value / y) return true; } return false; } template<> bool WillOverflow<ir::Mod>(int64_t x, int64_t y, int64_t min_value, int64_t max_value) { return y == 0; } } // namespace arith } // namespace tvm #endif // TVM_ARITHMETIC_INT_OP_OVERFLOW_H_