<html>
    <head>
      <base href="https://bugs.llvm.org/">
    </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 - misoptimization with defaulting to POWER7 and newer"
   href="https://bugs.llvm.org/show_bug.cgi?id=45709">45709</a>
          </td>
        </tr>

        <tr>
          <th>Summary</th>
          <td>misoptimization with defaulting to POWER7 and newer
          </td>
        </tr>

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

        <tr>
          <th>Version</th>
          <td>10.0
          </td>
        </tr>

        <tr>
          <th>Hardware</th>
          <td>Other
          </td>
        </tr>

        <tr>
          <th>OS</th>
          <td>FreeBSD
          </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>pkubaj@anongoth.pl
          </td>
        </tr>

        <tr>
          <th>CC</th>
          <td>llvm-bugs@lists.llvm.org, nemanja.i.ibm@gmail.com
          </td>
        </tr></table>
      <p>
        <div>
        <pre>Reduced test case:
class a {
  void b();
  void m_fn2();
  int c;
  float d[];
};
void a ::b() {
  float e;
  for (int f; f <= c; f++)
    if (e < d[f])
      e = d[f];
  if (e)
    m_fn2();
}

Compile with:
c++ -ffast-math -O2 -c sms.cpp

It builds fine without -ffast-math, or when lowering optimizations to -O1, or
after adding -mcpu=power7 (power8 or power9 are also ok for clang).

Result:
Illegal instruction</pre>
        </div>
      </p>


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