<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 - Run loop-idiom with -Oz"
   href="https://bugs.llvm.org/show_bug.cgi?id=48737">48737</a>
          </td>
        </tr>

        <tr>
          <th>Summary</th>
          <td>Run loop-idiom with -Oz
          </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>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>Loop Optimizer
          </td>
        </tr>

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

        <tr>
          <th>Reporter</th>
          <td>david.bolvansky@gmail.com
          </td>
        </tr>

        <tr>
          <th>CC</th>
          <td>llvm-bugs@lists.llvm.org
          </td>
        </tr></table>
      <p>
        <div>
        <pre>void copy(float *__restrict__ d, float *__restrict__ s, __SIZE_TYPE__ sz) {
    __SIZE_TYPE__ i;
    for (i = 0; i < sz; i++) {
        *d++ = *s++;
    }
}

-Os
copy(float*, float*, unsigned long):                           # @copy(float*,
float*, unsigned long)
        test    rdx, rdx
        je      .LBB0_2
        push    rax
        shl     rdx, 2
        call    memcpy@PLT
        add     rsp, 8
.LBB0_2:
        ret

-Oz
copy(float*, float*, unsigned long):                           # @copy(float*,
float*, unsigned long)
        xor     eax, eax
.LBB0_1:                                # =>This Inner Loop Header: Depth=1
        cmp     rdx, rax
        je      .LBB0_3
        movss   xmm0, dword ptr [rsi + 4*rax]   # xmm0 = mem[0],zero,zero,zero
        movss   dword ptr [rdi + 4*rax], xmm0
        inc     rax
        jmp     .LBB0_1
.LBB0_3:
        ret


<a href="https://godbolt.org/z/61EnzG">https://godbolt.org/z/61EnzG</a></pre>
        </div>
      </p>


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