small_vector<T> is misaligned on the stack in 32 bits about container HOT 2 OPEN

I confirm the existence of this problem on Windows x86 and that the workaround works.

I made the workaround generic:

template <class T, std::size_t N, class Allocator = void, class Options = void>
struct alignas(16) aligned_small_vector : boost::container::small_vector<T, N, Allocator, Options>
{
    using boost::container::small_vector<T, N, Allocator, Options>::small_vector;
};

from container.

It seems that the implementation for aligned_storage from Boost.Move uses double as the aligner type. Unfortunately, there is a compiler bug, If a user declares a variable with 8 byte alignment, such as a double in x86 the compiler will not realign the stack.

Changing the implementation in Boost.Move to use "__declspec(align)" for 8 byte aligned types shows that MSVC will realign the stack properly:

boostorg/move@d0631ee

Could you test that after aplying Boost.Move's commit the issues is fixed?

from container.