<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 - [InstCombine] Infinite loop with select / icmp"
href="https://bugs.llvm.org/show_bug.cgi?id=48900">48900</a>
</td>
</tr>
<tr>
<th>Summary</th>
<td>[InstCombine] Infinite loop with select / icmp
</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>All
</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>florian_hahn@apple.com
</td>
</tr>
<tr>
<th>CC</th>
<td>llvm-bugs@lists.llvm.org
</td>
</tr></table>
<p>
<div>
<pre>Running `opt -instcombine` on the function below triggers an infinite loop in
instcombine and it looks like it does not get caught by the existing checks.
define i32 @clamp_check_for_no_infinite_loop3(i32 %i) {
%i2 = icmp ugt i32 %i, 1
%i3 = select i1 %i2, i32 %i, i32 1
%i4 = icmp sgt i32 %i3, 0
br i1 %i4, label %truelabel, label %falselabel
truelabel: ; preds = %0
%i5 = icmp slt i32 %i3, 2
%i6 = select i1 %i5, i32 %i3, i32 2
%i7 = shl nuw nsw i32 %i6, 2
ret i32 %i7
falselabel: ; preds = %0
ret i32 0
}
This is a reduced version of
<a href="https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=29957">https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=29957</a></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>