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    <body><table border="1" cellspacing="0" cellpadding="8">
        <tr>
          <th>Bug ID</th>
          <td><a class="bz_bug_link 
          bz_status_NEW "
   title="NEW - __builtin calls that would have produced integer constants expressions on their own do not produce integer constant when the builtin call is composed across a _Generic selection"
   href="https://bugs.llvm.org/show_bug.cgi?id=44684">44684</a>
          </td>
        </tr>

        <tr>
          <th>Summary</th>
          <td>__builtin calls that would have produced integer constants expressions on their own do not produce integer constant when the builtin call is composed across a _Generic selection
          </td>
        </tr>

        <tr>
          <th>Product</th>
          <td>clang
          </td>
        </tr>

        <tr>
          <th>Version</th>
          <td>9.0
          </td>
        </tr>

        <tr>
          <th>Hardware</th>
          <td>PC
          </td>
        </tr>

        <tr>
          <th>OS</th>
          <td>Linux
          </td>
        </tr>

        <tr>
          <th>Status</th>
          <td>NEW
          </td>
        </tr>

        <tr>
          <th>Severity</th>
          <td>enhancement
          </td>
        </tr>

        <tr>
          <th>Priority</th>
          <td>P
          </td>
        </tr>

        <tr>
          <th>Component</th>
          <td>C
          </td>
        </tr>

        <tr>
          <th>Assignee</th>
          <td>unassignedclangbugs@nondot.org
          </td>
        </tr>

        <tr>
          <th>Reporter</th>
          <td>pskocik@gmail.com
          </td>
        </tr>

        <tr>
          <th>CC</th>
          <td>blitzrakete@gmail.com, dgregor@apple.com, erik.pilkington@gmail.com, llvm-bugs@lists.llvm.org, richard-llvm@metafoo.co.uk
          </td>
        </tr></table>
      <p>
        <div>
        <pre>These all fail on clang while succeeding on gcc:

_Static_assert(_Generic(1u,unsigned:__builtin_clz)(1u),""); //✗
_Static_assert(_Generic(1u,unsigned:__builtin_popcount)(1u),""); //✗
_Static_assert(_Generic(1u,unsigned:__builtin_ctz)(2u),""); //✗

(Both gcc and clang successfully compile:

_Static_assert(__builtin_clz(1u),""); //✓
_Static_assert(__builtin_popcount(1u),""); //✓
_Static_assert(__builtin_ctz(2u),""); //✓
)

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


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