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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW --- - Constant folding disagrees with GCC and FPU on result of 0./0."
href="https://llvm.org/bugs/show_bug.cgi?id=24585">24585</a>
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<th>Summary</th>
<td>Constant folding disagrees with GCC and FPU on result of 0./0.
</td>
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<th>Product</th>
<td>libraries
</td>
</tr>
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<th>Version</th>
<td>trunk
</td>
</tr>
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<th>Hardware</th>
<td>PC
</td>
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<th>OS</th>
<td>Linux
</td>
</tr>
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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>Global Analyses
</td>
</tr>
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<th>Assignee</th>
<td>unassignedbugs@nondot.org
</td>
</tr>
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<th>Reporter</th>
<td>schaub.johannes@googlemail.com
</td>
</tr>
<tr>
<th>CC</th>
<td>llvm-bugs@lists.llvm.org
</td>
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<th>Classification</th>
<td>Unclassified
</td>
</tr></table>
<p>
<div>
<pre>The following testcase outputs "1 -1" instead of the same value two times
#include <iostream>
#include <math.h>
int main() {
double zero = 0.0;
volatile double zerov = 0.0;
std::cout << copysign(1., zero/zero) << " " << copysign(1., zerov/zerov);
}
GCC outputs "-1 -1" (it has the sign bit set to 1).</pre>
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