<html>
<head>
<base href="http://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 --- - Propagation of select values when followed by branch on same condition"
href="http://llvm.org/bugs/show_bug.cgi?id=18754">18754</a>
</td>
</tr>
<tr>
<th>Summary</th>
<td>Propagation of select values when followed by branch on same condition
</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>prc33@cam.ac.uk
</td>
</tr>
<tr>
<th>CC</th>
<td>llvmbugs@cs.uiuc.edu
</td>
</tr>
<tr>
<th>Classification</th>
<td>Unclassified
</td>
</tr></table>
<p>
<div>
<pre>The following code (with the knowledge that %data != null) is not optimised:
%1 = icmp eq i32 %flag, 1
%2 = select i1 %1, %foo* %data, %foo* null
%3 = icmp eq %foo* %2, null
br i1 %3, label %failure, label %success
Ideally LLVM would notice that %1 == !%3, and therefore that it can be changed
to:
%1 = icmp eq i32 %flag, 1
br i1 %1, label %success, label %failure
with %2 replaced by %data in %success (and its successors), and %2 replaced by
null in %failure.
Discussion on LLVMdev suggests this is related to: pr13307, pr10254, pr13590</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>