<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 - Debug info makes build results non-deterministic"
   href="https://bugs.llvm.org/show_bug.cgi?id=52441">52441</a>
          </td>
        </tr>

        <tr>
          <th>Summary</th>
          <td>Debug info makes build results non-deterministic
          </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>normal
          </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>ilya.yanok@gmail.com
          </td>
        </tr>

        <tr>
          <th>CC</th>
          <td>llvm-bugs@lists.llvm.org
          </td>
        </tr></table>
      <p>
        <div>
        <pre>Created <span class=""><a href="attachment.cgi?id=25430" name="attach_25430" title="Input that triggers the bug">attachment 25430</a> <a href="attachment.cgi?id=25430&action=edit" title="Input that triggers the bug">[details]</a></span>
Input that triggers the bug

This was found by Rust here: <a href="https://github.com/rust-lang/rust/issues/90301">https://github.com/rust-lang/rust/issues/90301</a>

I was able to extract an LLVM example (see attached).

One can test it with

$ llc -O0 input.ll

Running it several times (usually 10 is enough) you will get slightly different
results.

I've bisected it to commit 1db137b1859692ae33228c530d4df9f2431b2151
Author: Stephen Tozer <<a href="mailto:Stephen.Tozer@Sony.com">Stephen.Tozer@Sony.com</a>>
Date:   Wed Mar 10 14:25:09 2021 +0000

    [DebugInfo] Handle DBG_VALUES with multiple variable location operands in
MIR

    This patch adds handling for DBG_VALUE_LIST in the MIR-passes (after
    finalize-isel), excluding the debug liveness passes and DWARF emission.
This
    most significantly affects MachineSink, which now needs to consider all
used
    registers of a debug value when sinking, but for most passes this change is
    simply replacing getDebugOperand(0) with an iteration over all debug
operands.

    Differential Revision: <a href="https://reviews.llvm.org/D92578">https://reviews.llvm.org/D92578</a></pre>
        </div>
      </p>


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