<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 - Instsimplify: uadd_overflow(X, undef) is not undef"
href="https://bugs.llvm.org/show_bug.cgi?id=42209">42209</a>
</td>
</tr>
<tr>
<th>Summary</th>
<td>Instsimplify: uadd_overflow(X, undef) is not undef
</td>
</tr>
<tr>
<th>Product</th>
<td>libraries
</td>
</tr>
<tr>
<th>Version</th>
<td>trunk
</td>
</tr>
<tr>
<th>Hardware</th>
<td>All
</td>
</tr>
<tr>
<th>OS</th>
<td>All
</td>
</tr>
<tr>
<th>Status</th>
<td>NEW
</td>
</tr>
<tr>
<th>Severity</th>
<td>normal
</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>nunoplopes@sapo.pt
</td>
</tr>
<tr>
<th>CC</th>
<td>lebedev.ri@gmail.com, llvm-bugs@lists.llvm.org, regehr@cs.utah.edu, sanjoy@playingwithpointers.com
</td>
</tr></table>
<p>
<div>
<pre>test/Transforms/InstSimplify/call.ll contains a few incorrect transformations
when undef is involved.
For example, when %v is zero, there's no overflow, so can't fold this to undef:
define {i8, i1} @test_uadd3(i8 %v) {
%0:
%result = uadd_overflow i8 %v, undef
ret {i8, i1} %result
}
=>
define {i8, i1} @test_uadd3(i8 %v) {
%0:
ret {i8, i1} undef
}
Transformation doesn't verify!
ERROR: Value mismatch
Example:
i8 %v = #x00 (0)
Source:
{i8, i1} %result = { ?, #x0 }
Target:
Source value: { ?, #x0 }
Target value: { #x00, #x1 }</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>