C++17 introduced an alignment argument to ::operator new(). It’s important to note that if you allocate something using aligned new, you absolutely must deallocate it using aligned delete, or the behavior is undefined. LLVM 10.x takes advantage of this alignment parameter, if the compiler supports it. That means if you are compiling on Windows with MSVC set to C++14, __cpp_aligned_new is not defined and the extra argument isn’t passed. Otherwise, if it’s compiled with MSVC set to C++17,...