<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 - Missing optimization for sibling address"
   href="https://bugs.llvm.org/show_bug.cgi?id=50414">50414</a>
          </td>
        </tr>

        <tr>
          <th>Summary</th>
          <td>Missing optimization for sibling address
          </td>
        </tr>

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

        <tr>
          <th>Version</th>
          <td>12.0
          </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>zhongyunde@tom.com
          </td>
        </tr>

        <tr>
          <th>CC</th>
          <td>arnaud.degrandmaison@arm.com, llvm-bugs@lists.llvm.org, smithp352@googlemail.com, Ties.Stuij@arm.com
          </td>
        </tr></table>
      <p>
        <div>
        <pre>cat test.c

extern double top[100];

int foo (long long j, double a) {
  top[j] += a;
  return 0;
}

clang12 test.c -O3 -Wall --std c89 -S -o clang.s
foo:                                    // @foo
        .cfi_startproc
// %bb.0:                               // %entry
        adrp    x9, top
        lsl     x8, x0, #3              -- redundant  
        add     x9, x9, :lo12:top
        ldr     d1, [x9, x8]    --> ldr d1, [x9, x0, lsl 3]
        mov     w0, wzr
        fadd    d0, d1, d0  
        str     d0, [x9, x8]    --> str d0, [x9, x0, lsl 3]
        ret</pre>
        </div>
      </p>


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