<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 --- - Incorrect code of variable arguments"
   href="http://llvm.org/bugs/show_bug.cgi?id=17789">17789</a>
          </td>
        </tr>

        <tr>
          <th>Summary</th>
          <td>Incorrect code of variable arguments
          </td>
        </tr>

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

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

        <tr>
          <th>Reporter</th>
          <td>ishiura-compiler@ml.kwansei.ac.jp
          </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 3.4 (based on LLVM 3.4svn) for i386 target miscompiles the following
code.

    $ cat error.c

    #include <stdarg.h>

    struct triple_s { short a; short b; short c; };

    void func(struct triple_s s, ... );

    int main(void)
    {
            struct triple_s s = { 1, 1, 1 };
            int x = 1;

            func(s, x);

            return 0;
    }

    void func(struct triple_s s, ... )
    {
            int x;

            va_list ap;
            va_start(ap, s);
            x = va_arg(ap, int);
            va_end(ap);

            if( x != 1 ) { __builtin_abort(); }
    }

    $ clang error.c
    $ ./a.out
    Aborted (core dumped)

The value of x was 65556 instead of 1.
There was no problem with an x86_64 target (but fails with -m32 option).</pre>
        </div>
      </p>
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