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<base href="https://bugs.llvm.org/">
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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - [DAGCombiner] visitBRCOND() leads to UNREACHABLE: "Operand not processed?""
href="https://bugs.llvm.org/show_bug.cgi?id=36901">36901</a>
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<th>Summary</th>
<td>[DAGCombiner] visitBRCOND() leads to UNREACHABLE: "Operand not processed?"
</td>
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<th>Product</th>
<td>libraries
</td>
</tr>
<tr>
<th>Version</th>
<td>trunk
</td>
</tr>
<tr>
<th>Hardware</th>
<td>PC
</td>
</tr>
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<th>OS</th>
<td>Linux
</td>
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<th>Status</th>
<td>NEW
</td>
</tr>
<tr>
<th>Severity</th>
<td>enhancement
</td>
</tr>
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<th>Priority</th>
<td>P
</td>
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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>
<tr>
<th>CC</th>
<td>llvm-bugs@lists.llvm.org
</td>
</tr></table>
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<pre>Created <span class=""><a href="attachment.cgi?id=20122" name="attach_20122" title="reduced testcase">attachment 20122</a> <a href="attachment.cgi?id=20122&action=edit" title="reduced testcase">[details]</a></span>
reduced testcase
DAG:
t5: i32 = Constant<0>
t6: i32 = Constant<-1>
t7: ch = setgt
t4: i1 = setcc undef:i32, Constant:i32<-8>, setlt:ch
t11: i1 = or t4, Constant:i1<-1>
t10: i1 = setcc undef:i32, Constant:i32<-9>, setlt:ch
t12: i1 = and t11, t10
t0: ch = EntryToken
t13: i1 = xor t11, Constant:i1<-1>
t15: ch = brcond t0, t13, BasicBlock:ch< 0x5373f68>
t17: ch = br t15, BasicBlock:ch< 0x5374428>
visitBRCOND() calls rebuildSetCC() which correctly replaces t13 like:
t15: ch = brcond t0, Constant:i1<0>, BasicBlock:ch< 0x5373f68>
After visit(N) (in combine()) returns, the DAG looks like
t0: ch = EntryToken
t5: i32 = Constant<0>
t6: i32 = Constant<-1>
t7: ch = setgt
t4: i1 = setcc undef:i32, Constant:i32<-8>, setlt:ch
t11: i1 = or t4, Constant:i1<-1>
t10: i1 = setcc undef:i32, Constant:i32<-9>, setlt:ch
t12: i1 = and t11, t10
t15: ch = brcond t0, Constant:i1<0>, BasicBlock:ch< 0x5373f68>
t17: ch = br t15, BasicBlock:ch< 0x5374428>
However, the returned RV looks like
t19: ch = brcond t0, t19, BasicBlock:ch< 0x5373f68>
, which has itself as operand! This is inserted into the DAG...
Runline:
llc -mtriple=s390x-linux-gnu -mcpu=z13 tc_brcond.ll</pre>
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