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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - Miscompile for AArch64, possibly related to llvm.umul.with.overflow.i64"
href="https://bugs.llvm.org/show_bug.cgi?id=47679">47679</a>
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<th>Summary</th>
<td>Miscompile for AArch64, possibly related to llvm.umul.with.overflow.i64
</td>
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<th>Product</th>
<td>new-bugs
</td>
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<th>Version</th>
<td>11.0
</td>
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<th>Hardware</th>
<td>Other
</td>
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<th>OS</th>
<td>All
</td>
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<th>Status</th>
<td>NEW
</td>
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<th>Severity</th>
<td>release blocker
</td>
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<th>Priority</th>
<td>P
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<th>Component</th>
<td>new bugs
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<th>Assignee</th>
<td>unassignedbugs@nondot.org
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<th>Reporter</th>
<td>kinke@gmx.net
</td>
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<th>CC</th>
<td>htmldeveloper@gmail.com, llvm-bugs@lists.llvm.org
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<p>
<div>
<pre>Created <span class=""><a href="attachment.cgi?id=24004" name="attach_24004" title="unoptimized input IR">attachment 24004</a> <a href="attachment.cgi?id=24004&action=edit" title="unoptimized input IR">[details]</a></span>
unoptimized input IR
Hi,
I'm seeing test regressions with LLVM 11 (rc3 and rc4) on AArch64 for an
*unoptimized* function performing a i64 multiply-with-overflow-check
(apparently wrongly reporting overflows in some cases). Unfortunately, I don't
have an AArch64 box to test, and no according qemu setup, so this is a bit of a
shot in the dark. I've attached the source IR.
The generated *optimized* machine assembly is identical for LLVM 10 and 11, and
seems to work fine. The *unoptimized* assembly versions differ though; I don't
have a clue about AArch64, but in the optimized case and in the unoptimized 10
version, there's a `cmp` right after the `umulh`, and that's missing in the
unoptimized 11 version...</pre>
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</p>
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