<html>
<head>
<base href="https://llvm.org/bugs/" />
</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 --- - Code is not optimized with -O2 when used with variadic arguments"
href="https://llvm.org/bugs/show_bug.cgi?id=28844">28844</a>
</td>
</tr>
<tr>
<th>Summary</th>
<td>Code is not optimized with -O2 when used with variadic arguments
</td>
</tr>
<tr>
<th>Product</th>
<td>clang
</td>
</tr>
<tr>
<th>Version</th>
<td>3.9
</td>
</tr>
<tr>
<th>Hardware</th>
<td>All
</td>
</tr>
<tr>
<th>OS</th>
<td>All
</td>
</tr>
<tr>
<th>Status</th>
<td>NEW
</td>
</tr>
<tr>
<th>Severity</th>
<td>normal
</td>
</tr>
<tr>
<th>Priority</th>
<td>P
</td>
</tr>
<tr>
<th>Component</th>
<td>LLVM Codegen
</td>
</tr>
<tr>
<th>Assignee</th>
<td>unassignedclangbugs@nondot.org
</td>
</tr>
<tr>
<th>Reporter</th>
<td>kris@jusiak.net
</td>
</tr>
<tr>
<th>CC</th>
<td>llvm-bugs@lists.llvm.org
</td>
</tr>
<tr>
<th>Classification</th>
<td>Unclassified
</td>
</tr></table>
<p>
<div>
<pre>Created <span class=""><a href="attachment.cgi?id=16881" name="attach_16881" title="Simple case demonstrating the bug">attachment 16881</a> <a href="attachment.cgi?id=16881&action=edit" title="Simple case demonstrating the bug">[details]</a></span>
Simple case demonstrating the bug
Started to happen in 3.9 and trunk. Previous versions work fine.
struct config {
static int f(...) { return 42; }
};
int main() {
return config::f();
}
Clang-3.9: compiled with -O2 -S gives:
xor %eax,%eax
jmpq 0x403540 <_ZN6config1fEz>
Clang-3.8 or less, or GCC, or MSVC gives:
movl $42, %eax
retq
It's just a simplified example, however, technic with variadic args is popular
in the context of SFINAE.
Due to this issue C++14 dependency injection library
(<a href="https://github.com/boost-experimental/di">https://github.com/boost-experimental/di</a>) is not optimizing bindings with
clang-3.9.</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>