<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 - AArch64 missed optimization involving "or(frameindex, n)""
href="https://bugs.llvm.org/show_bug.cgi?id=46151">46151</a>
</td>
</tr>
<tr>
<th>Summary</th>
<td>AArch64 missed optimization involving "or(frameindex, n)"
</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>Windows NT
</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>Backend: AArch64
</td>
</tr>
<tr>
<th>Assignee</th>
<td>unassignedbugs@nondot.org
</td>
</tr>
<tr>
<th>Reporter</th>
<td>efriedma@quicinc.com
</td>
</tr>
<tr>
<th>CC</th>
<td>arnaud.degrandmaison@arm.com, llvm-bugs@lists.llvm.org, smithp352@googlemail.com, Ties.Stuij@arm.com
</td>
</tr></table>
<p>
<div>
<pre>Consider the following testcase:
int test(long n, void test2(int*)) {
int a[4] __attribute((aligned(16)));
test2(a);
return a[n & 3];
}
(Similar patterns can come up with variable-index extractelement.)
Currently, we generate something like the following:
mov x20, sp
and x8, x19, #0x3
bfi x20, x8, #2, #2
ldr w0, [x20]
If the "aligned" attribute is removed, we instead generate:
mov x20, sp
and x8, x19, #0x3
ldr w0, [x20, x8, lsl #2]</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>