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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - [DivRemPairs] Broken handling of RAUW"
href="https://bugs.llvm.org/show_bug.cgi?id=42823">42823</a>
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<th>Summary</th>
<td>[DivRemPairs] Broken handling of RAUW
</td>
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<th>Product</th>
<td>libraries
</td>
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<th>Version</th>
<td>trunk
</td>
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<th>Hardware</th>
<td>PC
</td>
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<th>OS</th>
<td>Linux
</td>
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<th>Status</th>
<td>NEW
</td>
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<th>Severity</th>
<td>enhancement
</td>
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<th>Priority</th>
<td>P
</td>
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<th>Component</th>
<td>Scalar Optimizations
</td>
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<th>Assignee</th>
<td>unassignedbugs@nondot.org
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<th>Reporter</th>
<td>lebedev.ri@gmail.com
</td>
</tr>
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<th>CC</th>
<td>llvm-bugs@lists.llvm.org
</td>
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<p>
<div>
<pre><a href="https://reviews.llvm.org/D65298">https://reviews.llvm.org/D65298</a> added recomposition of expanded form of rem
into rem instruction, and that broke test-suite.
The bug is due to the fact that that pass does RAUW, but does nothing
about it's internal maps, the Values in them don't get updated.
That variation of a bug can be exposed even without that patch with this IR:
target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
target triple = "aarch64-unknown-linux-gnu"
define i32 @d(i32 %X, i32 %Y, i32 %Z) {
bb:
%t0 = mul nsw i32 %Z, %Y
%t1 = sdiv i32 %X, %t0
%t2 = mul nsw i32 %t0, %t1
%t3.recomposed = srem i32 %X, %t0
%t4 = sdiv i32 %t3.recomposed, %Y
%t5 = mul nsw i32 %t4, %Y
%t6.recomposed = srem i32 %t3.recomposed, %Y
ret i32 %t6.recomposed
}</pre>
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