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<base href="https://bugs.llvm.org/">
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<body><table border="1" cellspacing="0" cellpadding="8">
<tr>
<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - GVN drops nonnull metadata"
href="https://bugs.llvm.org/show_bug.cgi?id=35038">35038</a>
</td>
</tr>
<tr>
<th>Summary</th>
<td>GVN drops nonnull metadata
</td>
</tr>
<tr>
<th>Product</th>
<td>libraries
</td>
</tr>
<tr>
<th>Version</th>
<td>5.0
</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>yyc1992@gmail.com
</td>
</tr>
<tr>
<th>CC</th>
<td>llvm-bugs@lists.llvm.org
</td>
</tr></table>
<p>
<div>
<pre>Very similar to <a class="bz_bug_link
bz_status_RESOLVED bz_closed"
title="RESOLVED FIXED - instcombine drops load !nonnull metadata on an inttoptr/ptrtoint"
href="show_bug.cgi?id=30597">https://bugs.llvm.org/show_bug.cgi?id=30597</a> and
<a class="bz_bug_link
bz_status_RESOLVED bz_closed"
title="RESOLVED FIXED - SROA is dropping !nonnull/!range metadata"
href="show_bug.cgi?id=31142">https://bugs.llvm.org/show_bug.cgi?id=31142</a> but for GVN this time.
Code to reproduce:
```
target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
target triple = "x86_64-unknown-linux-gnu"
define i8* @f(i8** %v0, i8** %v1) {
top:
%v2 = load i8*, i8** %v0, !nonnull !0
store i8* %v2, i8** %v1
%v3 = load i8*, i8** %v1
ret i8* %v3
}
!0 = !{}
```
Running GVN produces
```
target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
target triple = "x86_64-unknown-linux-gnu"
define i8* @f(i8** %v0, i8** %v1) {
top:
%v2 = load i8*, i8** %v0
store i8* %v2, i8** %v1
ret i8* %v2
}
```
while running instcombine produces
```
target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
target triple = "x86_64-unknown-linux-gnu"
define i8* @f(i8** %v0, i8** %v1) {
top:
%0 = bitcast i8** %v0 to i64*
%v21 = load i64, i64* %0, align 8, !range !0
%1 = bitcast i8** %v1 to i64*
store i64 %v21, i64* %1, align 8
%v3.cast = inttoptr i64 %v21 to i8*
ret i8* %v3.cast
}
!0 = !{i64 1, i64 0}
```
The GVN version has deleted the `!nonnull` metadata on the load.</pre>
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