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    <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 - Optimizer hangs with std::complex and -ffast-math"
   href="https://bugs.llvm.org/show_bug.cgi?id=34078">34078</a>
          </td>
        </tr>

        <tr>
          <th>Summary</th>
          <td>Optimizer hangs with std::complex and -ffast-math
          </td>
        </tr>

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

        <tr>
          <th>Version</th>
          <td>4.0
          </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>unassignedbugs@nondot.org
          </td>
        </tr>

        <tr>
          <th>Reporter</th>
          <td>lkoppel@uwaterloo.ca
          </td>
        </tr>

        <tr>
          <th>CC</th>
          <td>llvm-bugs@lists.llvm.org
          </td>
        </tr></table>
      <p>
        <div>
        <pre>Created <span class=""><a href="attachment.cgi?id=18911" name="attach_18911" title="reduced .bc file from bugpoint">attachment 18911</a> <a href="attachment.cgi?id=18911&action=edit" title="reduced .bc file from bugpoint">[details]</a></span>
reduced .bc file from bugpoint

clang++ hangs indefinitely when compiling the following code with -O2
-ffast-math

#include <complex>
void f(double A) {
  double B = 1. - A - pow(A, 2) / 2.;
  std::complex<double> C = B + B;
  std::complex<double> D = 1. / C;
}

or the following code with -O1 -ffast-math

#include <complex>
void f(double A) {
  double B = 1. - A - pow(A, 2) / 2.;
  std::complex<double> C = B + B;
}

(I originally observed the bug while compiling
<a href="https://github.com/laurentkneip/opengv/blob/master/src/math/roots.cpp">https://github.com/laurentkneip/opengv/blob/master/src/math/roots.cpp</a>, and
reduced).

Bugpoint suggests it is the reassociate pass. Reduced output attached.</pre>
        </div>
      </p>


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