<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 - Converting invoke to call does not transfer "MD_mem_parallel_loop_access" metadata"
href="https://bugs.llvm.org/show_bug.cgi?id=39994">39994</a>
</td>
</tr>
<tr>
<th>Summary</th>
<td>Converting invoke to call does not transfer "MD_mem_parallel_loop_access" metadata
</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>Transformation Utilities
</td>
</tr>
<tr>
<th>Assignee</th>
<td>unassignedbugs@nondot.org
</td>
</tr>
<tr>
<th>Reporter</th>
<td>moritz.kreutzer@siemens.com
</td>
</tr>
<tr>
<th>CC</th>
<td>llvm-bugs@lists.llvm.org
</td>
</tr></table>
<p>
<div>
<pre>Hi,
We have observed a problem with vectorization and the newest LLVM/Clang trunk
(older versions seem to be affected as well). We have a loop with a potential
race condition for which we force vectorization using "#pragma clang loop
vectorize(assume_safety)." Despite that, Clang fails to vectorize our loop
reporting that it "cannot identify array bounds." After investigating the IR
after each pass, we found a potential cause of this issue. It seems like the
"MD_mem_parallel_loop_access" metadata did not get transferred over when
converting an invoke to a call. We could fix the problem by adding the
following line to the changeToCall() method in Local.cpp:
NewCall->copyMetadata(*II, LLVMContext::MD_mem_parallel_loop_access);
This is similar to to what is done in SROA, but we are not sure whether this is
a valid fix for the observed issue.
Please note that we are aware of the WIP under D52116 and D52117, but our fix
(with additional copying of "LLVMContext::MD_access_group" in the same call)
was also required to get the loop vectorized after applying those two patches.
Thanks,
Moritz</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>