<html>
    <head>
      <base href="https://llvm.org/bugs/" />
    </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 --- - SystemZ backend: failing assert in ScheduleDAGRRList"
   href="https://llvm.org/bugs/show_bug.cgi?id=28753">28753</a>
          </td>
        </tr>

        <tr>
          <th>Summary</th>
          <td>SystemZ backend: failing assert in ScheduleDAGRRList
          </td>
        </tr>

        <tr>
          <th>Product</th>
          <td>new-bugs
          </td>
        </tr>

        <tr>
          <th>Version</th>
          <td>trunk
          </td>
        </tr>

        <tr>
          <th>Hardware</th>
          <td>Other
          </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>new bugs
          </td>
        </tr>

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

        <tr>
          <th>Reporter</th>
          <td>colpell@ca.ibm.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>Created <span class=""><a href="attachment.cgi?id=16831" name="attach_16831" title="C source">attachment 16831</a> <a href="attachment.cgi?id=16831&action=edit" title="C source">[details]</a></span>
C source

To reproduce, compile bug.c with
clang -O1 -target s390x-linux-gnu -c bug.c

Compilation aborts during "DAG->DAG Pattern Instruction Selection" with this
failed assert:

llvm/lib/CodeGen/SelectionDAG/ScheduleDAGRRList.cpp:1197: llvm::MVT
getPhysicalRegisterVT(llvm::SDNode*, unsigned int, const
llvm::TargetInstrInfo*): Assertion `MCID.ImplicitDefs && "Physical reg def must
be in implicit def list!"' failed.

Compiling at -O0 does not reproduce the failure. Changing "shift" in bug.c to a
value lower than 64 also causes compilation to pass.

LLVM/Clang is from SVN trunk 276984.</pre>
        </div>
      </p>
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