<html>
<head>
<base href="https://bugs.freedesktop.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 - Incorrect code generation for atomic operations if HAVE_INTEL_ATOMIC_PRIMITIVES defined"
href="https://bugs.freedesktop.org/show_bug.cgi?id=103559">103559</a>
</td>
</tr>
<tr>
<th>Summary</th>
<td>Incorrect code generation for atomic operations if HAVE_INTEL_ATOMIC_PRIMITIVES defined
</td>
</tr>
<tr>
<th>Product</th>
<td>cairo
</td>
</tr>
<tr>
<th>Version</th>
<td>unspecified
</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>medium
</td>
</tr>
<tr>
<th>Component</th>
<td>general
</td>
</tr>
<tr>
<th>Assignee</th>
<td>chris@chris-wilson.co.uk
</td>
</tr>
<tr>
<th>Reporter</th>
<td>fludkov.me@gmail.com
</td>
</tr>
<tr>
<th>QA Contact</th>
<td>cairo-bugs@cairographics.org
</td>
</tr></table>
<p>
<div>
<pre>It is a follow up after <a class="bz_bug_link
bz_status_RESOLVED bz_closed"
title="RESOLVED FIXED - Segmentation fault in _cairo_traps_compositor_glyphs"
href="show_bug.cgi?id=103037">https://bugs.freedesktop.org/show_bug.cgi?id=103037</a>.
The patch has the loop:
while (_cairo_atomic_int_get(once) != CAIRO_ATOMIC_ONCE_INITIALIZED) {}
When the library is compiled with HAVE_INTEL_ATOMIC_PRIMITIVES:
/* whether memory barriers are needed around atomic operations */
/* #undef ATOMIC_OP_NEEDS_MEMORY_BARRIER */
...
#define HAVE_INTEL_ATOMIC_PRIMITIVES 1
The _cairo_atomic_int_get will be defined as:
# define _cairo_atomic_int_get(x) (*x)
Which will make this loop to hot-loop forever, because gcc will optimize it and
read once instead of reading on every loop iteration.
Does anybody actually use the implementation under HAVE_INTEL_ATOMIC_PRIMITIVES
define? According to git history, the code under HAVE_CXX11_ATOMIC_PRIMITIVES
define landed after the one HAVE_INTEL_ATOMIC_PRIMITIVES. But should not it
have completely replaced it?</pre>
</div>
</p>
<hr>
<span>You are receiving this mail because:</span>
<ul>
<li>You are the QA Contact for the bug.</li>
</ul>
</body>
</html>