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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW --- - Detect integer demotions in UBSan"
href="http://llvm.org/bugs/show_bug.cgi?id=21530">21530</a>
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<th>Summary</th>
<td>Detect integer demotions in UBSan
</td>
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<th>Product</th>
<td>clang
</td>
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<th>Version</th>
<td>trunk
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<th>Hardware</th>
<td>All
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<th>OS</th>
<td>All
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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
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<th>Component</th>
<td>-New Bugs
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<th>Assignee</th>
<td>unassignedclangbugs@nondot.org
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<th>Reporter</th>
<td>y.gribov@samsung.com
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<th>CC</th>
<td>kcc@google.com, llvmbugs@cs.uiuc.edu, vonosmas@gmail.com, y.gribov@samsung.com
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<th>Classification</th>
<td>Unclassified
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<p>
<div>
<pre>UBSan currently does not check integer demotions i.e. casts from wider integer
type to a smaller one. This is indeed not undefined behavior but rather
implementation defined. Still, loosing higher bits when downcasting ints to
chars is a constant source of bugs and it would be nice to have an optional
check for it (like we already have for float-cast-overflow).</pre>
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