<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 - SIMD & reduction on signed types emits sign-conversion diagnostic"
   href="https://bugs.llvm.org/show_bug.cgi?id=45959">45959</a>
          </td>
        </tr>

        <tr>
          <th>Summary</th>
          <td>SIMD & reduction on signed types emits sign-conversion diagnostic
          </td>
        </tr>

        <tr>
          <th>Product</th>
          <td>OpenMP
          </td>
        </tr>

        <tr>
          <th>Version</th>
          <td>unspecified
          </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>Clang Compiler Support
          </td>
        </tr>

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

        <tr>
          <th>Reporter</th>
          <td>clang@evan.coeusgroup.com
          </td>
        </tr>

        <tr>
          <th>CC</th>
          <td>llvm-bugs@lists.llvm.org
          </td>
        </tr></table>
      <p>
        <div>
        <pre>With -Wsign-conversion, an & reduction on an integer value will emit a
diagnostic.  Here is a simple test case:

  int foo(int* v);

  int foo(int* v) {
    int r = ~0;

    #pragma omp simd reduction(&:r)
    for (int i = 0 ; i < 8 ; i++) {
      r &= v[i];
    }

    return r;
  }

When compiling:

  $ clang -Weverything -fopenmp-simd -c -o simd.o simd.c
  simd.c:6:32: warning: implicit conversion changes signedness: 'unsigned int'
to 'int' [-Wsign-conversion]
    #pragma omp simd reduction(&:r)
                               ^
  1 warning generated.</pre>
        </div>
      </p>


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