Changes

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

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

[Tests] Added tests for new instcombine or simplification; NFC

[InstSimplify] Add (~A & B) | ~(A | B) --> ~A

[RISCV] Correct alignment settings for vector registers.

According to "9. Vector Memory Alignment Constraints" in V
specification, the alignment of vector memory access is aligned to the
size of the element. In our current implementation, we support ELEN up
to 64. We could assume the alignment of vector registers is 64 under the
assumption.

Differential Revision: https://reviews.llvm.org/D94751