<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 - Missing combine of shl+bswap to rol"
href="https://bugs.llvm.org/show_bug.cgi?id=52049">52049</a>
</td>
</tr>
<tr>
<th>Summary</th>
<td>Missing combine of shl+bswap to rol
</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>david.bolvansky@gmail.com
</td>
</tr>
<tr>
<th>CC</th>
<td>llvm-bugs@lists.llvm.org
</td>
</tr></table>
<p>
<div>
<pre>unsigned read_be16 (unsigned char *data)
{
return *(data + 1) | (*data << 8);
}
LLVM
read_be16(unsigned char*): # @read_be16(unsigned char*)
movzx eax, word ptr [rdi]
shl eax, 16
bswap eax
ret
GCC
read_be16(unsigned char*):
movzx eax, WORD PTR [rdi]
rol ax, 8
movzx eax, ax
ret
<a href="https://godbolt.org/z/s8ha55Y7W">https://godbolt.org/z/s8ha55Y7W</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>