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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW --- - UBSan error in lib/Target/R600/AMDGPUISelLowering.cpp (left shift of negative value)"
href="http://llvm.org/bugs/show_bug.cgi?id=20982">20982</a>
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<th>Summary</th>
<td>UBSan error in lib/Target/R600/AMDGPUISelLowering.cpp (left shift of negative value)
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<th>Product</th>
<td>new-bugs
</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>normal
</td>
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<th>Priority</th>
<td>P
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<th>Component</th>
<td>new bugs
</td>
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<th>Assignee</th>
<td>unassignedbugs@nondot.org
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</tr>
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<th>Reporter</th>
<td>vonosmas@gmail.com
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<th>CC</th>
<td>llvmbugs@cs.uiuc.edu, tstellar@gmail.com
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<th>Blocks</th>
<td>20815
</td>
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<th>Classification</th>
<td>Unclassified
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<p>
<div>
<pre>The following R600 test fails under UBSan bootstrap of LLVM:
LLVM :: CodeGen/R600/llvm.AMDGPU.bfe.i32.ll
The problem is the left shift of negative value in llvm::SDValue
constantFoldBFE<int32_t> in AMDGPUISelLowering.cpp (left shift of negative
value is undefined behavior in C).
To reproduce: build LLVM with just-built Clang and
-DLLVM_USE_SANITIZER=Undefined CMake option. I'm going to disable this specific
test case under UBSan, so that suppression will have to be removed as well.</pre>
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