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<base href="https://llvm.org/bugs/" />
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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW " title="NEW --- - Fast isel causes: Assertion `MRI->getVRegDef(reg) && "Register use before def!"" href="https://urldefense.proofpoint.com/v2/url?u=https-3A__llvm.org_bugs_show-5Fbug.cgi-3Fid-3D23640&d=AwMBaQ&c=8hUWFZcy2Z-Za5rBPlktOQ&r=pF93YEPyB-J_PERP4DUZOJDzFVX5ZQ57vQk33wu0vio&m=3_zx7l7ukBxTpiyKhcpXR3GAqOX7F4avyzV7ozO_0HU&s=3v4bEw5nnPnbuhe0PMjE3wGPToRtp6cGcVBOt2PrFrM&e=">23640</a>
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<th>Summary</th>
<td>Fast isel causes: Assertion `MRI->getVRegDef(reg) && "Register use before def!"
</td>
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<th>Product</th>
<td>libraries
</td>
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<th>Version</th>
<td>trunk
</td>
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<th>Hardware</th>
<td>PC
</td>
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<th>OS</th>
<td>Linux
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<th>Status</th>
<td>NEW
</td>
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<th>Severity</th>
<td>normal
</td>
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<th>Priority</th>
<td>P
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<th>Component</th>
<td>Backend: PowerPC
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<th>Assignee</th>
<td>unassignedbugs@nondot.org
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<th>Reporter</th>
<td>hfinkel@anl.gov
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<th>CC</th>
<td>llvmbugs@cs.uiuc.edu
</td>
</tr>
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<th>Classification</th>
<td>Unclassified
</td>
</tr></table>
<p>
<div>
<pre>Created <span class=""><a href="attachment.cgi?id=14375" name="attach_14375" title="bugpoint reduced test case">attachment 14375</a> <a href="attachment.cgi?id=14375&action=edit" title="bugpoint reduced test case">[details]</a></span>
bugpoint reduced test case
Run the attached (bugpoint-reduced) test case with:
llc -O0 -relocation-model=pic < boost_O0_bug.ll
and with trunk you'll get:
llc: /src/llvm/lib/CodeGen/LiveVariables.cpp:133: void
llvm::LiveVariables::HandleVirtRegUse(unsigned int, llvm::MachineBasicBlock*,
llvm::MachineInstr*): Assertion `MRI->getVRegDef(reg) && "Register use before
def!"' failed.
It is complaining about this:
Predecessors according to CFG: BB#5
%vreg12<def> = IMPLICIT_DEF; G8RC:%vreg12
%vreg11<def> = CMPD %vreg12, %vreg13; CRRC:%vreg11 G8RC:%vreg12,%vreg13
BCC 68, %vreg11, <BB#9>; CRRC:%vreg11
B <BB#7>
and it is indeed unclear where vreg13 is supposed to be defined (it is not
anywhere in the function).</pre>
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