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      <base href="https://bugs.llvm.org/">
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    <body><table border="1" cellspacing="0" cellpadding="8">
        <tr>
          <th>Bug ID</th>
          <td><a class="bz_bug_link 
          bz_status_NEW "
   title="NEW - [AArch64] Very bad code generation with shuffles and llvm.aarch64.neon.smull.v4i32"
   href="https://bugs.llvm.org/show_bug.cgi?id=40632">40632</a>
          </td>
        </tr>

        <tr>
          <th>Summary</th>
          <td>[AArch64] Very bad code generation with shuffles and llvm.aarch64.neon.smull.v4i32
          </td>
        </tr>

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

        <tr>
          <th>Version</th>
          <td>trunk
          </td>
        </tr>

        <tr>
          <th>Hardware</th>
          <td>PC
          </td>
        </tr>

        <tr>
          <th>OS</th>
          <td>Windows NT
          </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>Backend: AArch64
          </td>
        </tr>

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

        <tr>
          <th>Reporter</th>
          <td>efriedma@quicinc.com
          </td>
        </tr>

        <tr>
          <th>CC</th>
          <td>arnaud.degrandmaison@arm.com, florian_hahn@apple.com, llvm-bugs@lists.llvm.org, maratek@gmail.com, peter.smith@linaro.org, resistor@mac.com, Ties.Stuij@arm.com
          </td>
        </tr></table>
      <p>
        <div>
        <pre>#include <arm_neon.h>

int32x4_t f(int32x4_t vacc, int16x8_t vb, int16x8_t va) {
    return vmull_lane_s16(vget_low_s16(vb), vget_low_s16(va), 0);
}

Produces:

        dup     v0.8h, v2.h[0]
        ext     v0.16b, v0.16b, v0.16b, #8
        smull   v0.4s, v1.4h, v0.4h
        ret

Something is obviously going terribly wrong here.

I'll have a patch soon, I think.</pre>
        </div>
      </p>


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