<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 --- - Changing regalloc order breaks "lencod" on native arm linux builds."
   href="http://llvm.org/bugs/show_bug.cgi?id=18996">18996</a>
          </td>
        </tr>

        <tr>
          <th>Summary</th>
          <td>Changing regalloc order breaks "lencod" on native arm linux builds.
          </td>
        </tr>

        <tr>
          <th>Product</th>
          <td>new-bugs
          </td>
        </tr>

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

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

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

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

        <tr>
          <th>Reporter</th>
          <td>atrick@apple.com
          </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>The LNT run of lencod broke here:
<a href="http://lab.llvm.org:8011/builders/clang-native-arm-lnt/builds/5356">http://lab.llvm.org:8011/builders/clang-native-arm-lnt/builds/5356</a>

After this commit:

Author: atrick
Date: Wed Feb 26 16:07:26 2014
New Revision: 202304

URL: <a href="http://llvm.org/viewvc/llvm-project?rev=202304&view=rev">http://llvm.org/viewvc/llvm-project?rev=202304&view=rev</a>
Log:
Add a limit to the heuristic that register allocates instructions in local
order.

This handles pathological cases in which we see 2x increase in spill
code for large blocks (~50k instructions). I don't have a unit test
for this behavior.

Fixes rdar://16072279.

Modified:
   llvm/trunk/lib/CodeGen/RegAllocGreedy.cpp

There is a downstream codegen bug that is only exposed by a certain register
allocation order, and only currently reproducible on native arm linux builds.</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>