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    <head>
      <base href="https://llvm.org/bugs/" />
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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 --- - Infinitely decreased stack pointer"
   href="https://llvm.org/bugs/show_bug.cgi?id=30200">30200</a>
          </td>
        </tr>

        <tr>
          <th>Summary</th>
          <td>Infinitely decreased stack pointer
          </td>
        </tr>

        <tr>
          <th>Product</th>
          <td>libraries
          </td>
        </tr>

        <tr>
          <th>Version</th>
          <td>3.8
          </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>normal
          </td>
        </tr>

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

        <tr>
          <th>Component</th>
          <td>Backend: X86
          </td>
        </tr>

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

        <tr>
          <th>Reporter</th>
          <td>llvm@henning-thielemann.de
          </td>
        </tr>

        <tr>
          <th>CC</th>
          <td>llvm-bugs@lists.llvm.org
          </td>
        </tr>

        <tr>
          <th>Classification</th>
          <td>Unclassified
          </td>
        </tr></table>
      <p>
        <div>
        <pre>Created <span class=""><a href="attachment.cgi?id=17185" name="attach_17185" title="LL file for loop with ever decreasing stack pointer">attachment 17185</a> <a href="attachment.cgi?id=17185&action=edit" title="LL file for loop with ever decreasing stack pointer">[details]</a></span>
LL file for loop with ever decreasing stack pointer

I attach a small example of code that I generated programmatically via MCJIT
and optimized with -O1 to simplify it. It is a loop containing some alloca (but
problem remains with malloc/free). When run it crashes if the loop count is big
enough. The generated X86 assembly code looks like the stack pointer is
decremented repeatedly by these instructions:

        movq    %rsp, %rax
        leaq    -32(%rax), %rsp</pre>
        </div>
      </p>
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          <li>You are on the CC list for the bug.</li>
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