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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - different result from __builtin_add_overflow in constant expresion"
href="https://bugs.llvm.org/show_bug.cgi?id=41552">41552</a>
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<th>Summary</th>
<td>different result from __builtin_add_overflow in constant expresion
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<th>Product</th>
<td>clang
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<th>Version</th>
<td>7.0
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<th>Hardware</th>
<td>PC
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<th>OS</th>
<td>Linux
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<th>Status</th>
<td>NEW
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<th>Severity</th>
<td>normal
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<th>Priority</th>
<td>P
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<th>Component</th>
<td>C++
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<th>Assignee</th>
<td>unassignedclangbugs@nondot.org
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<th>Reporter</th>
<td>john@mcfarlane.name
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<th>CC</th>
<td>blitzrakete@gmail.com, dgregor@apple.com, erik.pilkington@gmail.com, llvm-bugs@lists.llvm.org, richard-llvm@metafoo.co.uk
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<p>
<div>
<pre>Description:
Normally, when passing a combination of large signed and unsigned integer
values to the generic overload of __builtin_add_overflow and requesting back an
unsigned integer, the function correctly identifies overflow. When the same
operation takes place in a constant expression, __builtin_add_overflow fails to
identify that the overflow took place.
Example:
<a href="https://wandbox.org/permlink/hDCXNEThgH3NmdLz">https://wandbox.org/permlink/hDCXNEThgH3NmdLz</a>
Affected:
This affects 7.x and upward. Earlier versions do not support
__builtin_add_overflow in constant expressions.
This affects C++14 and later. A repro for C++11 is not possible due to
limitations imposed on constexpr fns.</pre>
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