<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 - Missed rotate oportunity"
href="https://bugs.llvm.org/show_bug.cgi?id=41098">41098</a>
</td>
</tr>
<tr>
<th>Summary</th>
<td>Missed rotate oportunity
</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>Not sure if reported or not.. please close if a duplicate..
struct edge {
unsigned char from;
unsigned char to;
};
void reverse_edge(struct edge *e) {
unsigned char tmp = e->from;
e->from = e->to;
e->to = tmp;
}
Clang -O3:
reverse_edge(edge*): # @reverse_edge(edge*)
mov al, byte ptr [rdi]
mov cl, byte ptr [rdi + 1]
mov byte ptr [rdi], cl
mov byte ptr [rdi + 1], al
ret
GCC generates
reverse_edge(edge*):
rol WORD PTR [rdi], 8
ret</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>