// A must be power of two.
template <unsigned A>
void* AlignMem(void* addr)
{
    unsigned a = A - 1;
    return (void*)((unsigned)addr + a) & ~a;
}

void* ptr = UPP::MemoryAlloc(sizeof(object) + alignment - 1)
object* o = new(AlignMem<alignment>(ptr)) object(aarg1, arg2, e.t.c.);
...
o->~object();
UPP::MemoryFree(ptr);