[eigen] Alignment of a derived class

[Martin Sälzle <martin.saelzle@xxxxxxx>]

Hi, 

Please consider this example:

struct Base
{
  Eigen::Vector4f vec4f_base;
  EIGEN_MAKE_ALIGNED_OPERATOR_NEW
};

struct Derived1 : public Base
{
  Eigen::Vector4f vec4f_derived_1;
  EIGEN_MAKE_ALIGNED_OPERATOR_NEW
};

struct Derived2 : public Base
{
  Eigen::Vector4f vec4f_derived_2;
};

I would like to know if Derived1 and / or Derived 2 are aligned, given that Base is aligned. 
The next question is if EIGEN_MAKE_ALIGNED_OPERATOR_NEW is needed in the derived class (Derived1 vs Derived2).
The final question is what would happen for Derived1 if Base does note have EIGEN_MAKE_ALIGNED_OPERATOR_NEW?

thank you and best regards,
Martin