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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW --- - Support conditional returns and conditional indirect calls"
href="https://llvm.org/bugs/show_bug.cgi?id=23417">23417</a>
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<th>Summary</th>
<td>Support conditional returns and conditional indirect calls
</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>Other
</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>enhancement
</td>
</tr>
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<th>Priority</th>
<td>P
</td>
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<th>Component</th>
<td>Backend: SystemZ
</td>
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<th>Assignee</th>
<td>unassignedbugs@nondot.org
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<th>Reporter</th>
<td>uweigand@de.ibm.com
</td>
</tr>
<tr>
<th>CC</th>
<td>llvmbugs@cs.uiuc.edu
</td>
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<th>Classification</th>
<td>Unclassified
</td>
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<p>
<div>
<pre>System z uses an unconditional branch instruction to implement returns
and indirect calls. However, the BRANCH ON CONDITION instruction could
also be used with a condition field, which would allow implementing
*conditional* returns and *conditional* indirect calls (if circumstances
otherwise allow), e.g. from source code like this:
if (cond)
return;
if (cond)
func();
This is not yet implemented.
By adding appropriate instructions to PredicateInstruction and related
routines, the IfConversion pass should be able to detect and optimize
those situations.</pre>
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