<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 - MachineVerifier doesn't check live-in lists"
   href="https://bugs.llvm.org/show_bug.cgi?id=33182">33182</a>
          </td>
        </tr>

        <tr>
          <th>Summary</th>
          <td>MachineVerifier doesn't check live-in lists
          </td>
        </tr>

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

        <tr>
          <th>Version</th>
          <td>4.0
          </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>enhancement
          </td>
        </tr>

        <tr>
          <th>Priority</th>
          <td>P
          </td>
        </tr>

        <tr>
          <th>Component</th>
          <td>Common Code Generator Code
          </td>
        </tr>

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

        <tr>
          <th>Reporter</th>
          <td>matze@braunis.de
          </td>
        </tr>

        <tr>
          <th>CC</th>
          <td>llvm-bugs@lists.llvm.org
          </td>
        </tr></table>
      <p>
        <div>
        <pre>After some recent fixes I wondered why the machine verifier didn't catch the
problems. Turns out we do not check live-in lists:
Example:

<span class="quote">> cat t.mir</span >
# RUN: llc -o - %s -mtriple=aarch64-- -run-pass=none -verify-machineinstrs |
FileCheck %s
---
# CHECK-LABEL: name: func
name: func
tracksRegLiveness: true
body: |
  bb.0:
    liveins: %x5
    %x5 = ADDXrr killed %x5, killed %x5

  bb.1:
    liveins: %x10
    %x10 = ADDXrr killed %x10, killed %x10
...

The register %x10 claimed to be live-in in bb.1 is not live at the end of bb.0
yet the MachineVerifier doesn't complain.</pre>
        </div>
      </p>


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