| 1 | //===--- IncorrectRoundingsCheck.h - clang-tidy -----------------*- C++ -*-===// |
| 2 | // |
| 3 | // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
| 4 | // See https://llvm.org/LICENSE.txt for license information. |
| 5 | // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
| 6 | // |
| 7 | //===----------------------------------------------------------------------===// |
| 8 | |
| 9 | #ifndef LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_BUGPRONE_INCORRECTROUNDINGSCHECK_H_ |
| 10 | #define |
| 11 | |
| 12 | #include "../ClangTidyCheck.h" |
| 13 | |
| 14 | namespace clang::tidy::bugprone { |
| 15 | |
| 16 | /// Checks the usage of patterns known to produce incorrect rounding. |
| 17 | /// Programmers often use |
| 18 | /// (int)(double_expression + 0.5) |
| 19 | /// to round the double expression to an integer. The problem with this |
| 20 | /// 1. It is unnecessarily slow. |
| 21 | /// 2. It is incorrect. The number 0.499999975 (smallest representable float |
| 22 | /// number below 0.5) rounds to 1.0. Even worse behavior for negative |
| 23 | /// numbers where both -0.5f and -1.4f both round to 0.0. |
| 24 | class IncorrectRoundingsCheck : public ClangTidyCheck { |
| 25 | public: |
| 26 | IncorrectRoundingsCheck(StringRef Name, ClangTidyContext *Context) |
| 27 | : ClangTidyCheck(Name, Context) {} |
| 28 | void registerMatchers(ast_matchers::MatchFinder *Finder) override; |
| 29 | void check(const ast_matchers::MatchFinder::MatchResult &Result) override; |
| 30 | }; |
| 31 | |
| 32 | } // namespace clang::tidy::bugprone |
| 33 | |
| 34 | #endif // LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_BUGPRONE_INCORRECTROUNDINGSCHECK_H_ |
| 35 | |