<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 - Better optimizations for logical ops with bit fields"
href="https://bugs.llvm.org/show_bug.cgi?id=40750">40750</a>
</td>
</tr>
<tr>
<th>Summary</th>
<td>Better optimizations for logical ops with bit fields
</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>Tested on Intel Haswell 4720HQ
struct test {
int a : 1;
int b : 1; // if changed to 2, GCC and Clang produces same codegen
};
int get(struct test *s) {
return s->a || s->b;
}
GCC:
get:
xor eax, eax
test BYTE PTR [rdi], 3
setne al
ret
Clang:
get: # @get
movzx ecx, byte ptr [rdi]
mov eax, 1
test cl, 1
jne .LBB0_2
shr ecx
and ecx, 1
mov eax, ecx
.LBB0_2:
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>