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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - Failure to optimize away abs check based on known range of variable"
href="https://bugs.llvm.org/show_bug.cgi?id=45687">45687</a>
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<th>Summary</th>
<td>Failure to optimize away abs check based on known range of variable
</td>
</tr>
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<th>Product</th>
<td>libraries
</td>
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<th>Version</th>
<td>trunk
</td>
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<th>Hardware</th>
<td>PC
</td>
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<th>OS</th>
<td>Linux
</td>
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<th>Status</th>
<td>NEW
</td>
</tr>
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<th>Severity</th>
<td>enhancement
</td>
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<th>Priority</th>
<td>P
</td>
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<th>Component</th>
<td>Scalar Optimizations
</td>
</tr>
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<th>Assignee</th>
<td>unassignedbugs@nondot.org
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<th>Reporter</th>
<td>gabravier@gmail.com
</td>
</tr>
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<th>CC</th>
<td>llvm-bugs@lists.llvm.org
</td>
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<p>
<div>
<pre>void g();
void f(int i)
{
__builtin_assume(i >= -1 && i <= 1);
if (abs(i) > 1)
g();
}
This can all be optimized out. GCC does this transformation, LLVM does not.
Comparison here : <a href="https://godbolt.org/z/cLcicG">https://godbolt.org/z/cLcicG</a></pre>
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