title: From LLVM, how can I determine the architecture's maximum alignment?
body: <p>I have cases where I need to <code>alloca</code> space for an object with size, layout, and alignment that is unknown at compile time. These values are accessible at runtime, but as far as I can tell, the <code>align</code> attribute on an <code>alloca</code> instruction must be compile-time constant, rather than an instruction argument.</p>
  <p>How can I safely obtain an <code>align</code> value which will be strict enough to align to any primitive data type on the target platform? (The equivalent of this in C++ would be <code>alignof(std::max_align_t)</code>).</p>