<html>
    <head>
      <base href="https://bugs.llvm.org/">
    </head>
    <body><span class="vcard"><a class="email" href="mailto:richard-llvm@metafoo.co.uk" title="Richard Smith <richard-llvm@metafoo.co.uk>"> <span class="fn">Richard Smith</span></a>
</span> changed
          <a class="bz_bug_link 
          bz_status_RESOLVED  bz_closed"
   title="RESOLVED INVALID - Clang looses constexpr."
   href="https://bugs.llvm.org/show_bug.cgi?id=41093">bug 41093</a>
          <br>
             <table border="1" cellspacing="0" cellpadding="8">
          <tr>
            <th>What</th>
            <th>Removed</th>
            <th>Added</th>
          </tr>

         <tr>
           <td style="text-align:right;">Resolution</td>
           <td>---
           </td>
           <td>INVALID
           </td>
         </tr>

         <tr>
           <td style="text-align:right;">Status</td>
           <td>NEW
           </td>
           <td>RESOLVED
           </td>
         </tr></table>
      <p>
        <div>
            <b><a class="bz_bug_link 
          bz_status_RESOLVED  bz_closed"
   title="RESOLVED INVALID - Clang looses constexpr."
   href="https://bugs.llvm.org/show_bug.cgi?id=41093#c1">Comment # 1</a>
              on <a class="bz_bug_link 
          bz_status_RESOLVED  bz_closed"
   title="RESOLVED INVALID - Clang looses constexpr."
   href="https://bugs.llvm.org/show_bug.cgi?id=41093">bug 41093</a>
              from <span class="vcard"><a class="email" href="mailto:richard-llvm@metafoo.co.uk" title="Richard Smith <richard-llvm@metafoo.co.uk>"> <span class="fn">Richard Smith</span></a>
</span></b>
        <pre>This is a GCC bug. This code:

constexpr void table_map_one_helper(const Table& t, OutTable& out_table, Op op)
{
  constexpr auto multi_s = t.math.template as_multi_s<idx>();
//...

is ill-formed, because the reference 't' cannot be used in a constant
expression (naming a reference resolves it to the referenced object, which is
unknown here).

You can fix your code by changing that to

  constexpr auto multi_s = decltype(t.math)::template as_multi_s<idx>();

<a href="https://gcc.godbolt.org/z/MBb1-9">https://gcc.godbolt.org/z/MBb1-9</a></pre>
        </div>
      </p>


      <hr>
      <span>You are receiving this mail because:</span>

      <ul>
          <li>You are on the CC list for the bug.</li>
      </ul>
    </body>
</html>