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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 - The compiler-rt leads to loss of floating precision when GCC use compiler-rt instead of libgcc"
   href="https://bugs.llvm.org/show_bug.cgi?id=40453">40453</a>
          </td>
        </tr>

        <tr>
          <th>Summary</th>
          <td>The compiler-rt leads to loss of floating precision when GCC use compiler-rt instead of libgcc
          </td>
        </tr>

        <tr>
          <th>Product</th>
          <td>compiler-rt
          </td>
        </tr>

        <tr>
          <th>Version</th>
          <td>7.0
          </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>enhancement
          </td>
        </tr>

        <tr>
          <th>Priority</th>
          <td>P
          </td>
        </tr>

        <tr>
          <th>Component</th>
          <td>compiler-rt
          </td>
        </tr>

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

        <tr>
          <th>Reporter</th>
          <td>messagezsl@outlook.com
          </td>
        </tr>

        <tr>
          <th>CC</th>
          <td>llvm-bugs@lists.llvm.org
          </td>
        </tr></table>
      <p>
        <div>
        <pre>Hi all

   Now we are try to use compiler-rt instead of libgcc when we use GCC to
compile program! but we find that comliper-rt will leads to loss of floating
precision, the following is detailed information:

  The program:

  int main()
  {
    double  one  = 1.0;
    double  tmp = 1.7976931348623157E308;
    double  ret =  one / tmp;

    printf(" ret : %E   \n", ret);

  }


  1、GCC compiler program and use libgcc:

  result:  

  ret : 5.562685E-309

  2、GCC compiler program and use compiler-rt:

  result:  

  ret : 0.000000E+00

  If anyone know the reason why compiler-rt will leads to loss of floating
precision
, Please reply soon when you are convenient! I will appreciate it!</pre>
        </div>
      </p>


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