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<base href="https://llvm.org/bugs/" />
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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW --- - Incorrect code generation of conditional compares for AArch64"
href="https://llvm.org/bugs/show_bug.cgi?id=24459">24459</a>
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<tr>
<th>Summary</th>
<td>Incorrect code generation of conditional compares for AArch64
</td>
</tr>
<tr>
<th>Product</th>
<td>libraries
</td>
</tr>
<tr>
<th>Version</th>
<td>trunk
</td>
</tr>
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<th>Hardware</th>
<td>PC
</td>
</tr>
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<th>OS</th>
<td>All
</td>
</tr>
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<th>Status</th>
<td>NEW
</td>
</tr>
<tr>
<th>Severity</th>
<td>normal
</td>
</tr>
<tr>
<th>Priority</th>
<td>P
</td>
</tr>
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<th>Component</th>
<td>Backend: AArch64
</td>
</tr>
<tr>
<th>Assignee</th>
<td>unassignedbugs@nondot.org
</td>
</tr>
<tr>
<th>Reporter</th>
<td>kristof.beyls@gmail.com
</td>
</tr>
<tr>
<th>CC</th>
<td>llvm-bugs@lists.llvm.org
</td>
</tr>
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<th>Classification</th>
<td>Unclassified
</td>
</tr></table>
<p>
<div>
<pre>Created <span class=""><a href="attachment.cgi?id=14725" name="attach_14725" title="reduced test case">attachment 14725</a> <a href="attachment.cgi?id=14725&action=edit" title="reduced test case">[details]</a></span>
reduced test case
It seems that <a href="http://llvm.org/viewvc/llvm-project?view=revision&revision=242436">http://llvm.org/viewvc/llvm-project?view=revision&revision=242436</a>
introduced a correctness regression.
The attached reduced test case (still not tiny though) shows that at
optimization level -O1, this code gets miscompiled, while it still was getting
compiled correctly by clang r242436.
$ ./llvm.org/cmake-build-r242435/bin/clang
./reproducer/aarch64_tree_tests_reduce.c -S -O1 -o ./reproducer/t.242435.s;
$ ./llvm.org/cmake-build-r242436/bin/clang
./reproducer/aarch64_tree_tests_reduce.c -S -O1 -o ./reproducer/t.242436.s;
$ ./llvm.org/cmake-build-r242435/bin/clang
./reproducer/aarch64_tree_tests_reduce.c -O1 -o ./reproducer/t.242435.exe;
$ ./llvm.org/cmake-build-r242436/bin/clang
./reproducer/aarch64_tree_tests_reduce.c -O1 -o ./reproducer/t.242436.exe;
$ ./reproducer/t.242435.exe
$ ./reproducer/t.242436.exe
Expected: 0000000000000000 Got: 0000000000000000</pre>
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