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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 - CodeExtractor miscompiles invokes with uses outside of the extraction region"
href="https://bugs.llvm.org/show_bug.cgi?id=40455">40455</a>
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<th>Summary</th>
<td>CodeExtractor miscompiles invokes with uses outside of the extraction region
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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>All
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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>Interprocedural Optimizations
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<th>Assignee</th>
<td>unassignedbugs@nondot.org
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<th>Reporter</th>
<td>vsk@apple.com
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<th>CC</th>
<td>llvm-bugs@lists.llvm.org
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<p>
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<pre>The pattern that triggers the miscompile is:
```
extract1:
%call = invoke i8* @foo(...)
to label %outside-extraction-region unwind label %extract2
extract2:
landingpad i8 cleanup
ret void
outside-extraction-region:
call void @use(i8* %call)
ret void
```
When CodeExtractor extracts the blocks extract{1,2}, it sees that %call is used
outside of the extraction region. So it extracts the invoke and stores its
result in an in-out param ("%call.out"). But the store is placed in
%outside-extraction-region, i.e., in the wrong function.
To fix this, exit stubs need to be created before stores to outputs occur.
Then, the store to the in-out param can be placed in the exit stub where it
belongs.</pre>
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</p>
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