<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 - [Compile Time] 35% spent in GVN"
href="https://bugs.llvm.org/show_bug.cgi?id=44356">44356</a>
</td>
</tr>
<tr>
<th>Summary</th>
<td>[Compile Time] 35% spent in GVN
</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>paulsson@linux.vnet.ibm.com
</td>
</tr>
<tr>
<th>CC</th>
<td>llvm-bugs@lists.llvm.org
</td>
</tr></table>
<p>
<div>
<pre>Created <span class=""><a href="attachment.cgi?id=22957" name="attach_22957" title="testcases in compressed tar file">attachment 22957</a> <a href="attachment.cgi?id=22957&action=edit" title="testcases in compressed tar file">[details]</a></span>
testcases in compressed tar file
This csmith program is more than 2x compile time than gcc (even with
-disable-phi-elim-edge-splitting):
time gcc -O3: 25s
time clang -O3 -march=z13 crash6.i -o a.out -w -c -mllvm
-disable-phi-elim-edge-splitting -ftime-report
user 1m8.106s
Global Value Numbering 35%
I tried to reduce the test case with creduce, and got about 80% size reduction.
GVN is still dominating the compile time, which is now less than one second.
clang -O3 -march=z13 tc_GVN_CTime.i -o a.out -w -c
user 0m0.784s</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>