Revert "Fix llvm::Optional build breaks in MSVC using std::is_trivially_copyable"

This reverts commit 854f098.

This breaks compilation with clang-cl on Windows, while in a MSVC 16.8 cmd.exe.
This also breaks PPC: http://lab.llvm.org:8011/#/builders/93/builds/1435
And: https://reviews.llvm.org/D93510#2497737

Author: aganea

llvm/include/llvm/ADT/Optional.h

@@ -33,12 +33,7 @@ namespace optional_detail {
 struct in_place_t {};
 
 /// Storage for any type.
-template <typename T, bool = (std::is_trivially_copy_constructible<T>::value &&
-                              std::is_trivially_copy_assignable<T>::value &&
-                              (std::is_trivially_move_constructible<T>::value ||
-                               !std::is_move_constructible<T>::value) &&
-                              (std::is_trivially_move_assignable<T>::value ||
-                               !std::is_move_assignable<T>::value))>
+template <typename T, bool = is_trivially_copyable<T>::value>
 class OptionalStorage {
   union {
     char empty;

llvm/unittests/ADT/OptionalTest.cpp

@@ -390,127 +390,6 @@ TEST(OptionalTest, ImmovableEmplace) {
   EXPECT_EQ(0u, Immovable::Destructions);
 }
 
-// Craft a class which is_trivially_copyable, but not
-// is_trivially_copy_constructible.
-struct NonTCopy {
-  NonTCopy() = default;
-
-  // Delete the volatile copy constructor to engage the "rule of 3" and delete
-  // any unspecified copy assignment or constructor.
-  NonTCopy(volatile NonTCopy const &) = delete;
-
-  // Leave the non-volatile default copy constructor unspecified (deleted by
-  // rule of 3)
-
-  // This template can serve as the copy constructor, but isn't chosen
-  // by =default in a class with a 'NonTCopy' member.
-  template <typename Self = NonTCopy>
-  NonTCopy(Self const &Other) : Val(Other.Val) {}
-
-  NonTCopy &operator=(NonTCopy const &) = default;
-
-  int Val{0};
-};
-
-#if defined(_MSC_VER) && _MSC_VER >= 1927
-// Currently only true on recent MSVC releases.
-static_assert(std::is_trivially_copyable<NonTCopy>::value,
-              "Expect NonTCopy to be trivially copyable");
-
-static_assert(!std::is_trivially_copy_constructible<NonTCopy>::value,
-              "Expect NonTCopy not to be trivially copy constructible.");
-#endif // defined(_MSC_VER) && _MSC_VER >= 1927
-
-TEST(OptionalTest, DeletedCopyConstructor) {
-
-  // Expect compile to fail if 'trivial' version of
-  // optional_detail::OptionalStorage is chosen.
-  using NonTCopyOptT = Optional<NonTCopy>;
-  NonTCopyOptT NonTCopy1;
-
-  // Check that the Optional can be copy constructed.
-  NonTCopyOptT NonTCopy2{NonTCopy1};
-
-  // Check that the Optional can be copy assigned.
-  NonTCopy1 = NonTCopy2;
-}
-
-// Craft a class which is_trivially_copyable, but not
-// is_trivially_copy_assignable.
-class NonTAssign {
-public:
-  NonTAssign() = default;
-  NonTAssign(NonTAssign const &) = default;
-
-  // Delete the volatile copy assignment to engage the "rule of 3" and delete
-  // any unspecified copy assignment or constructor.
-  NonTAssign &operator=(volatile NonTAssign const &) = delete;
-
-  // Leave the non-volatile default copy assignment unspecified (deleted by rule
-  // of 3).
-
-  // This template can serve as the copy assignment, but isn't chosen
-  // by =default in a class with a 'NonTAssign' member.
-  template <typename Self = NonTAssign>
-  NonTAssign &operator=(Self const &Other) {
-    A = Other.A;
-    return *this;
-  }
-
-  int A{0};
-};
-
-#if defined(_MSC_VER) && _MSC_VER >= 1927
-// Currently only true on recent MSVC releases.
-static_assert(std::is_trivially_copyable<NonTAssign>::value,
-              "Expect NonTAssign to be trivially copyable");
-
-static_assert(!std::is_trivially_copy_assignable<NonTAssign>::value,
-              "Expect NonTAssign not to be trivially assignable.");
-#endif // defined(_MSC_VER) && _MSC_VER >= 1927
-
-TEST(OptionalTest, DeletedCopyAssignment) {
-
-  // Expect compile to fail if 'trivial' version of
-  // optional_detail::OptionalStorage is chosen.
-  using NonTAssignOptT = Optional<NonTAssign>;
-  NonTAssignOptT NonTAssign1;
-
-  // Check that the Optional can be copy constructed.
-  NonTAssignOptT NonTAssign2{NonTAssign1};
-
-  // Check that the Optional can be copy assigned.
-  NonTAssign1 = NonTAssign2;
-}
-
-struct NoTMove {
-  NoTMove() = default;
-  NoTMove(NoTMove const &) = default;
-  NoTMove &operator=(NoTMove const &) = default;
-
-  // Delete move constructor / assignment.  Compiler should fall-back to the
-  // trivial copy constructor / assignment in the trivial OptionalStorage
-  // specialization.
-  NoTMove(NoTMove &&) = delete;
-  NoTMove &operator=(NoTMove &&) = delete;
-
-  int Val{0};
-};
-
-TEST(OptionalTest, DeletedMoveConstructor) {
-  using NoTMoveOptT = Optional<NoTMove>;
-
-  NoTMoveOptT NonTMove1;
-  NoTMoveOptT NonTMove2{std::move(NonTMove1)};
-
-  NonTMove1 = std::move(NonTMove2);
-
-  static_assert(
-      std::is_trivially_copyable<NoTMoveOptT>::value,
-      "Expect Optional<NoTMove> to still use the trivial specialization "
-      "of OptionalStorage despite the deleted move constructor / assignment.");
-}
-
 #if LLVM_HAS_RVALUE_REFERENCE_THIS
 
 TEST(OptionalTest, MoveGetValueOr) {