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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - [BranchFolding] Removing a block as dead while still used by branch instruction"
href="https://bugs.llvm.org/show_bug.cgi?id=50876">50876</a>
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<th>Summary</th>
<td>[BranchFolding] Removing a block as dead while still used by branch instruction
</td>
</tr>
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<th>Product</th>
<td>libraries
</td>
</tr>
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<th>Version</th>
<td>trunk
</td>
</tr>
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<th>Hardware</th>
<td>PC
</td>
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<th>OS</th>
<td>Linux
</td>
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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>Common Code Generator Code
</td>
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<th>Assignee</th>
<td>unassignedbugs@nondot.org
</td>
</tr>
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<th>Reporter</th>
<td>paulsson@linux.vnet.ibm.com
</td>
</tr>
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<th>CC</th>
<td>llvm-bugs@lists.llvm.org
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<div>
<pre>Created <span class=""><a href="attachment.cgi?id=24982" name="attach_24982" title="reduced testcase">attachment 24982</a> <a href="attachment.cgi?id=24982&action=edit" title="reduced testcase">[details]</a></span>
reduced testcase
It seems that BranchFolder::OptimizeBranches() is finding an MBB to have no
predecessors and therefore calls RemoveDeadBlock(). There is however still a
branch instruction branching to that target. As a result that instruction gets
a target '%bb.-1', since the block no longer exists.
llc -mcpu=arch13 -O3 -enable-tail-merge=false tc_ifconv.ll -o -
...
# %bb.5: # %bb13
blhr %r14
j ".LBB0_-1"
...
(j .LBB0_-1 since the block has been removed)</pre>
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