title: C++ constexpr does not work with reinterpret_cast
body: <p>In older gcc versions (~6.X) the following code worked, 
  however with newer version there are compile-errors.</p>
  
  <pre><code>struct test{
      constexpr static int* PORT1 = reinterpret_cast&lt;int*&gt;(0x12345678);
  };
  </code></pre>
  
  <p>Compiler:</p>
  
  <pre><code>error: reinterpret_cast from integer to pointer
  </code></pre>
  
  <p>A C-like cast doesnt work either.</p>
  
  <p>Note: Its for memory-maped-io, so i really want to read/write to a fixed address</p>