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6207a8299f
Current code breaks this version of MSVC due to a mismatch between `std::is_trivially_copyable` and `llvm::is_trivially_copyable` for `std::pair` instantiations. Hence I was attempting to use `std::is_trivially_copyable` to set `llvm::is_trivially_copyable<T>::value`. I spent some time root causing an `llvm::Optional` build error on MSVC 16.8.3 related to the change described above: ``` 62>C:\src\ocg_llvm\llvm-project\llvm\include\llvm/ADT/BreadthFirstIterator.h(96,12): error C2280: 'llvm::Optional<std::pair<std::pair<unsigned int,llvm::Graph<4>::NodeSubset> *,llvm::Optional<llvm::Graph<4>::ChildIterator>>> &llvm::Optional<std::pair<std::pair<unsigned int,llvm::Graph<4>::NodeSubset> *,llvm::Optional<llvm::Graph<4>::ChildIterator>>>::operator =(const llvm::Optional<std::pair<std::pair<unsigned int,llvm::Graph<4>::NodeSubset> *,llvm::Optional<llvm::Graph<4>::ChildIterator>>> &)': attempting to reference a deleted function (compiling source file C:\src\ocg_llvm\llvm-project\llvm\unittests\ADT\BreadthFirstIteratorTest.cpp) ... ``` The "trivial" specialization of `optional_detail::OptionalStorage` assumes that the value type is trivially copy constructible and trivially copy assignable. The specialization is invoked based on a check of `is_trivially_copyable` alone, which does not imply both `is_trivially_copy_assignable` and `is_trivially_copy_constructible` are true. [[ https://en.cppreference.com/w/cpp/named_req/TriviallyCopyable | According to the spec ]], a deleted assignment operator does not make `is_trivially_copyable` false. So I think all these properties need to be checked explicitly in order to specialize `OptionalStorage` to the "trivial" version: ``` /// Storage for any type. template <typename T, bool = std::is_trivially_copy_constructible<T>::value && std::is_trivially_copy_assignable<T>::value> class OptionalStorage { ``` Above fixed my build break in MSVC, but I think we need to explicitly check `is_trivially_copy_constructible` too since it might be possible the copy constructor is deleted. Also would be ideal to move over to `std::is_trivially_copyable` instead of the `llvm` namespace verson. Reviewed By: dblaikie Differential Revision: https://reviews.llvm.org/D93510 |
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| .. | ||
| ADT | ||
| Analysis | ||
| AsmParser | ||
| BinaryFormat | ||
| Bitcode | ||
| Bitstream | ||
| CodeGen | ||
| DebugInfo | ||
| Demangle | ||
| ExecutionEngine | ||
| FileCheck | ||
| Frontend | ||
| FuzzMutate | ||
| InterfaceStub | ||
| IR | ||
| LineEditor | ||
| Linker | ||
| MC | ||
| MI | ||
| Object | ||
| ObjectYAML | ||
| Option | ||
| Passes | ||
| ProfileData | ||
| Remarks | ||
| Support | ||
| TableGen | ||
| Target | ||
| TextAPI | ||
| tools | ||
| Transforms | ||
| XRay | ||
| CMakeLists.txt | ||
| unittest.cfg.in | ||