<html>
    <head>
      <base href="http://llvm.org/bugs/" />
    </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 --- - PowerPC cc clobber fails to clobber cr0"
   href="http://llvm.org/bugs/show_bug.cgi?id=21742">21742</a>
          </td>
        </tr>

        <tr>
          <th>Summary</th>
          <td>PowerPC cc clobber fails to clobber cr0
          </td>
        </tr>

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

        <tr>
          <th>Version</th>
          <td>trunk
          </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: PowerPC
          </td>
        </tr>

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

        <tr>
          <th>Reporter</th>
          <td>anton@samba.org
          </td>
        </tr>

        <tr>
          <th>CC</th>
          <td>llvmbugs@cs.uiuc.edu
          </td>
        </tr>

        <tr>
          <th>Classification</th>
          <td>Unclassified
          </td>
        </tr></table>
      <p>
        <div>
        <pre>I'm testing with a build that contains r223328. I notice at least one place
where using "cc" in the clobbers doesn't actually clobber cr0. We see the
andi./iselgt broken up by some inline assembly:

    12f0:       01 00 84 70     andi.   r4,r4,1
    12f4:       a8 18 80 7c     ldarx   r4,0,r3
    12f8:       78 a0 84 7c     andc    r4,r4,r20
    12fc:       ad 19 80 7c     stdcx.  r4,0,r3
    1300:       f4 ff a2 40     bne     12f4
    1304:       5e c8 b5 7e     iselgt  r21,r21,r25

If I convert the inline assembly to use "cr0", then we see the correct
behaviour.</pre>
        </div>
      </p>
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