[ADT] Drop llvm::Optional clang-specific optmization for trivially copyable types

Summary: This fixes libLLVM.so ABI mismatches between llvm compiled with clang and llvm compiled with gcc (PR39427). Reviewers: bkramer, sylvestre.ledru, mgorny, hans Reviewed By: bkramer, hans Subscribers: dexonsmith, kristina, llvm-commits Differential Revision: https://reviews.llvm.org/D54540 llvm-svn: 346985

Author: tstellar

llvm/include/llvm/ADT/Optional.h

@@ -108,24 +108,6 @@ template <typename T, bool IsPodLike> struct OptionalStorage {
  }
 };
 
-#if !defined(__GNUC__) || defined(__clang__) // GCC up to GCC7 miscompiles this.
-/// Storage for trivially copyable types only.
-template <typename T> struct OptionalStorage<T, true> {
- AlignedCharArrayUnion<T> storage;
- bool hasVal = false;
-
- OptionalStorage() = default;
-
- OptionalStorage(const T &y) : hasVal(true) { new (storage.buffer) T(y); }
- OptionalStorage &operator=(const T &y) {
- *reinterpret_cast<T *>(storage.buffer) = y;
- hasVal = true;
- return *this;
- }
-
- void reset() { hasVal = false; }
-};
-#endif
 } // namespace optional_detail
 
 template <typename T> class Optional {