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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - [APFloat] DoubleAPFloat::changeSign results in unusual values."
href="https://bugs.llvm.org/show_bug.cgi?id=34100">34100</a>
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<th>Summary</th>
<td>[APFloat] DoubleAPFloat::changeSign results in unusual values.
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<th>Product</th>
<td>libraries
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<th>Version</th>
<td>trunk
</td>
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<th>Hardware</th>
<td>All
</td>
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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>enhancement
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<th>Priority</th>
<td>P
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<th>Component</th>
<td>Support Libraries
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<th>Assignee</th>
<td>unassignedbugs@nondot.org
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<th>Reporter</th>
<td>edy.burt@gmail.com
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<th>CC</th>
<td>llvm-bugs@lists.llvm.org
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<p>
<div>
<pre>`DoubleAPFloat::make*` always uses positive zero `Floats[1]`, even if
`Floats[0]` becomes negative (for a `Neg=true` argument).
But `DoubleAPFloat::changeSign` changes *both* `Floats[0]` and `Floats[1]`,
even when the latter is zero.
That makes negating a positive zero or infinity that is *different* than the
ones created by `makeZero(true)` and `makeInf(true)`, respectively.
My fix would be to guard the `Floats[1].changeSign();` call by
`if(Floats[1].isFiniteNonZero())`.</pre>
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