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<body><span class="vcard"><a class="email" href="mailto:richard-llvm@metafoo.co.uk" title="Richard Smith <richard-llvm@metafoo.co.uk>"> <span class="fn">Richard Smith</span></a>
</span> changed
<a class="bz_bug_link
bz_status_RESOLVED bz_closed"
title="RESOLVED INVALID - UBSan: False positive for large left shift"
href="http://llvm.org/bugs/show_bug.cgi?id=19534">bug 19534</a>
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<th>What</th>
<th>Removed</th>
<th>Added</th>
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<td style="text-align:right;">Status</td>
<td>NEW
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<td>RESOLVED
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<td style="text-align:right;">CC</td>
<td>
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<td>richard-llvm@metafoo.co.uk
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<td style="text-align:right;">Resolution</td>
<td>---
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<td>INVALID
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<b><a class="bz_bug_link
bz_status_RESOLVED bz_closed"
title="RESOLVED INVALID - UBSan: False positive for large left shift"
href="http://llvm.org/bugs/show_bug.cgi?id=19534#c1">Comment # 1</a>
on <a class="bz_bug_link
bz_status_RESOLVED bz_closed"
title="RESOLVED INVALID - UBSan: False positive for large left shift"
href="http://llvm.org/bugs/show_bug.cgi?id=19534">bug 19534</a>
from <span class="vcard"><a class="email" href="mailto:richard-llvm@metafoo.co.uk" title="Richard Smith <richard-llvm@metafoo.co.uk>"> <span class="fn">Richard Smith</span></a>
</span></b>
<pre>UBSan is correct. C11 6.5.7/3 says:
"If the value of the right operand is negative or is greater than or equal to
the width of the promoted left operand, the behavior is undefined."
C++11 5.8/1 says:
"The behavior is undefined if the right operand is negative, or greater than or
equal to the length in bits of the promoted left operand."</pre>
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