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    <head>
      <base href="https://llvm.org/bugs/" />
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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] shufflevector with constants uses 4 ext instructions"
   href="https://llvm.org/bugs/show_bug.cgi?id=29125">29125</a>
          </td>
        </tr>

        <tr>
          <th>Summary</th>
          <td>[AArch64] shufflevector with constants uses 4 ext instructions
          </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>All
          </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>Backend: AArch64
          </td>
        </tr>

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

        <tr>
          <th>Reporter</th>
          <td>spatel+llvm@rotateright.com
          </td>
        </tr>

        <tr>
          <th>CC</th>
          <td>llvm-bugs@lists.llvm.org
          </td>
        </tr>

        <tr>
          <th>Classification</th>
          <td>Unclassified
          </td>
        </tr></table>
      <p>
        <div>
        <pre>I don't know AArch, but this doesn't look good:

define <4 x float> @goo(<4 x float> %x) {
  %shuf = shufflevector <4 x float> %x, <4 x float> <float undef, float 1.0,
float 2.0, float undef>, <4 x i32><i32 0, i32 5, i32 6, i32 3>
  ret <4 x float> %shuf
}

$ ./llc -o - min.ll -mtriple=aarch64
    adrp    x8, .LCPI1_0
    ldr    q1, [x8, :lo12:.LCPI1_0]
    ext    v1.16b, v0.16b, v1.16b, #12
    ext    v0.16b, v1.16b, v0.16b, #4
    ext    v1.16b, v1.16b, v1.16b, #8
    ext    v0.16b, v0.16b, v1.16b, #12
    ret

--------------------------------------------------------------------------

Should this be 'bsl'?

Or 2 inserts?
    fmov    s1, #1.00000000
    ins    v0.s[1], v1.s[0]
    fmov    s1, #2.00000000
    ins    v0.s[2], v1.s[0]
    ret</pre>
        </div>
      </p>
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