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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW --- - Enable the use of TBAA in CodeGen"
href="http://llvm.org/bugs/show_bug.cgi?id=18614">18614</a>
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<th>Summary</th>
<td>Enable the use of TBAA in CodeGen
</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
</td>
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<th>Status</th>
<td>NEW
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<th>Severity</th>
<td>normal
</td>
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<th>Priority</th>
<td>P
</td>
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<th>Component</th>
<td>Common Code Generator Code
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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
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<th>Classification</th>
<td>Unclassified
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<p>
<div>
<pre>In r200093, I disabled the use of TBAA in CodeGen, because of underlying
correctness issues. Specifically:
1. Stack coloring does not update TBAA when merging allocas. This is easy
enough to fix, but is not the largest problem.
2. CGP inserts ptrtoint/inttoptr pairs when sinking address computations.
Because BasicAA does not handle inttoptr, we'll often miss basic type punning
idioms that we need to catch so we don't miscompile real-world code (like
LLVM).
This second issue is the primary blocker, and can break self hosting (among
other things), especially when misched=shuffle is used.</pre>
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