<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 --- - __int128_t multiply with -fsanitize=undefined fails to link (undefined reference to __muloti4)"
   href="http://llvm.org/bugs/show_bug.cgi?id=16404">16404</a>
          </td>
        </tr>

        <tr>
          <th>Summary</th>
          <td>__int128_t multiply with -fsanitize=undefined fails to link (undefined reference to __muloti4)
          </td>
        </tr>

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

        <tr>
          <th>Version</th>
          <td>3.3
          </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>-New Bugs
          </td>
        </tr>

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

        <tr>
          <th>Reporter</th>
          <td>peter.maydell@linaro.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>clang fails to link code which does a multiply of two int128_t variables on
x86_64 if the code is compiled with -fsanitize=undefined : it fails with
"undefined reference to '__muloti4'. The same code compiles OK if the
-fsanitize argument is omitted:

cam-vm-266:precise:qemu$ cat /tmp/zz9.c
__int128_t a;
int main (void) {
  a = a * a;
  return 0;
}
cam-vm-266:precise:qemu$ clang /tmp/zz9.c -o /tmp/zz9
cam-vm-266:precise:qemu$ clang /tmp/zz9.c -fsanitize=undefined -o /tmp/zz9
/tmp/zz9-eAeaq5.o: In function `main':
/tmp/zz9.c:(.text+0x3b): undefined reference to `__muloti4'
clang: error: linker command failed with exit code 1 (use -v to see invocation)
cam-vm-266:precise:qemu$ clang --version
clang version 3.3 (tags/RELEASE_33/final)
Target: x86_64-unknown-linux-gnu
Thread model: posix

(I'm using the prebuilt clang binaries on Ubuntu 12.04:
<a href="http://llvm.org/releases/3.3/clang+llvm-3.3-amd64-Ubuntu-12.04.2.tar.gz">http://llvm.org/releases/3.3/clang+llvm-3.3-amd64-Ubuntu-12.04.2.tar.gz</a>)</pre>
        </div>
      </p>
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