<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] Failure to simplify add-of-negative+underflow check+null check of non-null base pointer"
href="https://bugs.llvm.org/show_bug.cgi?id=43259">43259</a>
</td>
</tr>
<tr>
<th>Summary</th>
<td>[InstCombine] Failure to simplify add-of-negative+underflow check+null check of non-null base pointer
</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>lebedev.ri@gmail.com
</td>
</tr>
<tr>
<th>CC</th>
<td>llvm-bugs@lists.llvm.org
</td>
</tr></table>
<p>
<div>
<pre>Again comes up in <a href="https://reviews.llvm.org/D67122">https://reviews.llvm.org/D67122</a>
Much like what we have in #43251,
for
#include <cassert>
char* test(char& base, signed long offset) {
__builtin_assume(offset < 0);
return &base + offset;
}
We produce
<a href="https://godbolt.org/z/r40U47">https://godbolt.org/z/r40U47</a>
and again those two icmp's can be merged:
<a href="https://rise4fun.com/Alive/8h2">https://rise4fun.com/Alive/8h2</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>