<html>
<head>
<base href="https://bugs.llvm.org/">
</head>
<body><table border="1" cellspacing="0" cellpadding="8">
<tr>
<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - Failure to optimize out redundant overflow check"
href="https://bugs.llvm.org/show_bug.cgi?id=49057">49057</a>
</td>
</tr>
<tr>
<th>Summary</th>
<td>Failure to optimize out redundant overflow check
</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>
<tr>
<th>Component</th>
<td>Scalar Optimizations
</td>
</tr>
<tr>
<th>Assignee</th>
<td>unassignedbugs@nondot.org
</td>
</tr>
<tr>
<th>Reporter</th>
<td>gabravier@gmail.com
</td>
</tr>
<tr>
<th>CC</th>
<td>llvm-bugs@lists.llvm.org
</td>
</tr></table>
<p>
<div>
<pre>unsigned foo(unsigned a, unsigned b)
{
unsigned sum = a + b;
if (sum < a)
abort();
if (sum < b)
abort();
return sum;
}
The second `if` condition can be optimized out. This transformation is done by
GCC, but not by LLVM.
Godbolt comparison: <a href="https://godbolt.org/z/KeGWx8">https://godbolt.org/z/KeGWx8</a>
alive2 check: <a href="https://alive2.llvm.org/ce/z/5hk_x7">https://alive2.llvm.org/ce/z/5hk_x7</a></pre>
</div>
</p>
<hr>
<span>You are receiving this mail because:</span>
<ul>
<li>You are on the CC list for the bug.</li>
</ul>
</body>
</html>