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<base href="https://bugs.llvm.org/">
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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - Missed pattern (A >= 0) & (B >= 0)"
href="https://bugs.llvm.org/show_bug.cgi?id=38781">38781</a>
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</tr>
<tr>
<th>Summary</th>
<td>Missed pattern (A >= 0) & (B >= 0)
</td>
</tr>
<tr>
<th>Product</th>
<td>libraries
</td>
</tr>
<tr>
<th>Version</th>
<td>trunk
</td>
</tr>
<tr>
<th>Hardware</th>
<td>PC
</td>
</tr>
<tr>
<th>OS</th>
<td>Linux
</td>
</tr>
<tr>
<th>Status</th>
<td>NEW
</td>
</tr>
<tr>
<th>Severity</th>
<td>enhancement
</td>
</tr>
<tr>
<th>Priority</th>
<td>P
</td>
</tr>
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<th>Component</th>
<td>Scalar Optimizations
</td>
</tr>
<tr>
<th>Assignee</th>
<td>unassignedbugs@nondot.org
</td>
</tr>
<tr>
<th>Reporter</th>
<td>david.bolvansky@gmail.com
</td>
</tr>
<tr>
<th>CC</th>
<td>llvm-bugs@lists.llvm.org
</td>
</tr></table>
<p>
<div>
<pre>int pat1 (int a, int b)
{
return (a >= 0) & (b >= 0); // can be transformed to (a | b) >= 0)
}
Clang:
pat1(int, int): # @pat1(int, int)
shr edi, 31
xor edi, 1
shr esi, 31
not esi
and esi, edi
mov eax, esi
ret
GCC:
pat1(int, int):
mov eax, esi
or eax, edi
not eax
shr eax, 31
ret</pre>
</div>
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