<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 --- - generator crashes with -mfpmath=387 -mno-sse"
   href="http://llvm.org/bugs/show_bug.cgi?id=22745">22745</a>
          </td>
        </tr>

        <tr>
          <th>Summary</th>
          <td>generator crashes with -mfpmath=387 -mno-sse
          </td>
        </tr>

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

        <tr>
          <th>Version</th>
          <td>3.5
          </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>LLVM Codegen
          </td>
        </tr>

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

        <tr>
          <th>Reporter</th>
          <td>dan.a.ibanez@gmail.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>Created <span class=""><a href="attachment.cgi?id=13966" name="attach_13966" title="preprocessed source and run script">attachment 13966</a> <a href="attachment.cgi?id=13966&action=edit" title="preprocessed source and run script">[details]</a></span>
preprocessed source and run script

I'm working on a meshing code and noticed different results on MacBook and
Lenovo machines. I think I've traced it to slightly different floating point
arithmetic. Per this StackOverflow answer:

<a href="http://stackoverflow.com/questions/17663780/is-there-a-document-describing-how-clang-handles-excess-floating-point-precision">http://stackoverflow.com/questions/17663780/is-there-a-document-describing-how-clang-handles-excess-floating-point-precision</a>

I tried compiling with "-O2 -mfpmath=387 -mno-sse", which crashed the clang
code generator. Attached is a tarball with the clang output and the temporary
files it requested.

I don't actually care so much whether clang can support this obscure
combination of flags, what I'm really interested in is what flags do I use to
get exactly the same answers on both machines.

I did see that <a class="bz_bug_link 
          bz_status_RESOLVED  bz_closed"
   title="RESOLVED FIXED - ccc/clang should recognize code generator target features"
   href="show_bug.cgi?id=3604">bug 3604</a> is a possible duplicate, but clang still crashes so
I'll submit this bug as a request that it not crash with these flags, instead
exit cleanly with a descriptive error.</pre>
        </div>
      </p>
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