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    <head>
      <base href="https://bugs.llvm.org/">
    </head>
    <body><table border="1" cellspacing="0" cellpadding="8">
        <tr>
          <th>Bug ID</th>
          <td><a class="bz_bug_link 
          bz_status_NEW "
   title="NEW - Loop with optimiser crashes simple coroutines"
   href="https://bugs.llvm.org/show_bug.cgi?id=46501">46501</a>
          </td>
        </tr>

        <tr>
          <th>Summary</th>
          <td>Loop with optimiser crashes simple coroutines
          </td>
        </tr>

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

        <tr>
          <th>Version</th>
          <td>10.0
          </td>
        </tr>

        <tr>
          <th>Hardware</th>
          <td>All
          </td>
        </tr>

        <tr>
          <th>OS</th>
          <td>All
          </td>
        </tr>

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

        <tr>
          <th>Severity</th>
          <td>release blocker
          </td>
        </tr>

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

        <tr>
          <th>Component</th>
          <td>C++2a
          </td>
        </tr>

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

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

        <tr>
          <th>CC</th>
          <td>blitzrakete@gmail.com, erik.pilkington@gmail.com, llvm-bugs@lists.llvm.org, richard-llvm@metafoo.co.uk
          </td>
        </tr></table>
      <p>
        <div>
        <pre>Created <span class=""><a href="attachment.cgi?id=23655" name="attach_23655" title="Short main.cpp shows simplified problem code">attachment 23655</a> <a href="attachment.cgi?id=23655&action=edit" title="Short main.cpp shows simplified problem code">[details]</a></span>
Short main.cpp shows simplified problem code

A simple loop (even one round only) will crash the LLVM frontend if it contains
a coroutine co_await. So...

A f() {
    for (int i=0; i<1; i++) 
    {
        co_await suspend_always{};
    }
}

...crashes the llvm front-end (I believe) when used with -Os or -O2, but the
following code (with the for statement removed) works fine:

A f() {
    co_await suspend_always{};
}</pre>
        </div>
      </p>


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