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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 - missing warning diagnosis of implicit conversion from 'double' to 'float'"
   href="https://bugs.llvm.org/show_bug.cgi?id=42058">42058</a>
          </td>
        </tr>

        <tr>
          <th>Summary</th>
          <td>missing warning diagnosis of implicit conversion from 'double' to 'float'
          </td>
        </tr>

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

        <tr>
          <th>Version</th>
          <td>6.0
          </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>Frontend
          </td>
        </tr>

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

        <tr>
          <th>Reporter</th>
          <td>tangyixuan@mail.dlut.edu.cn
          </td>
        </tr>

        <tr>
          <th>CC</th>
          <td>llvm-bugs@lists.llvm.org, neeilans@live.com, richard-llvm@metafoo.co.uk
          </td>
        </tr></table>
      <p>
        <div>
        <pre>For the following example, clang 6.0 misses the warning diagnosis of implicit
conversion from 'double' to 'float'. 

$ cat s.c
int main(){
        double w[2]={1.0,2.0},z[2]={2.0,4.0};
        float b[2];
        for(int j=1;j<2;j++){
                b[j]+=z[j]/w[j];
        }       
        return 0;
}
$ clang --version
clang version 6.0.0 (tags/RELEASE_600/final)
Target: x86_64-unknown-linux-gnu
Thread model: posix

$ clang -Wconversion s.c
No warning generated.

Under the same workstation:
$ clang-7.0 -Wconversion s.c
s.c:5:13: warning: implicit conversion when assigning computation result loses
floating-point precision: 'double' to 'float' [-Wconversion]
                b[j]+=z[j]/w[j];
                    ~~~~~^~~~~
1 warning generated.

$ clang-8.0 -Wimplicit-float-conversion s.c
s.c:5:13: warning: implicit conversion when assigning computation result loses
floating-point precision: 'double' to 'float' [-Wimplicit-float-conversion]
                b[j]+=z[j]/w[j];
                    ~~~~~^~~~~
1 warning generated.</pre>
        </div>
      </p>


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