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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW --- - Left shifting beyond sizeof int seems to have no effect."
href="https://llvm.org/bugs/show_bug.cgi?id=27334">27334</a>
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<th>Summary</th>
<td>Left shifting beyond sizeof int seems to have no effect.
</td>
</tr>
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<th>Product</th>
<td>clang
</td>
</tr>
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<th>Version</th>
<td>unspecified
</td>
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<th>Hardware</th>
<td>Macintosh
</td>
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<th>OS</th>
<td>MacOS X
</td>
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<th>Status</th>
<td>NEW
</td>
</tr>
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<th>Severity</th>
<td>normal
</td>
</tr>
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<th>Priority</th>
<td>P
</td>
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<th>Component</th>
<td>C++
</td>
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<th>Assignee</th>
<td>unassignedclangbugs@nondot.org
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<th>Reporter</th>
<td>norman.wilson@gmail.com
</td>
</tr>
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<th>CC</th>
<td>dgregor@apple.com, llvm-bugs@lists.llvm.org
</td>
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<th>Classification</th>
<td>Unclassified
</td>
</tr></table>
<p>
<div>
<pre>Best way to describe is show the code.
#include <cassert>
#include <iostream>
int
main()
{
int count = sizeof(unsigned) * 8;
unsigned x = (~0x0u) << count;
std::cout << std::hex << x << std::endl;
assert(x == 0);
}
I'd have thought that this shifting would result in x being zero or is this
undefined behaviour? This is using the following version:
bash-3.2$ clang++ --version
Apple LLVM version 7.0.2 (clang-700.1.81)
Target: x86_64-apple-darwin15.3.0
Thread model: posix</pre>
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