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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - LoopVersioning asserts when a runtime check is not necessary"
href="https://bugs.llvm.org/show_bug.cgi?id=52426">52426</a>
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<th>Summary</th>
<td>LoopVersioning asserts when a runtime check is not necessary
</td>
</tr>
<tr>
<th>Product</th>
<td>libraries
</td>
</tr>
<tr>
<th>Version</th>
<td>trunk
</td>
</tr>
<tr>
<th>Hardware</th>
<td>PC
</td>
</tr>
<tr>
<th>OS</th>
<td>Linux
</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>Scalar Optimizations
</td>
</tr>
<tr>
<th>Assignee</th>
<td>unassignedbugs@nondot.org
</td>
</tr>
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<th>Reporter</th>
<td>chang-sun.lin.jr@intel.com
</td>
</tr>
<tr>
<th>CC</th>
<td>llvm-bugs@lists.llvm.org
</td>
</tr></table>
<p>
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<pre>Created <span class=""><a href="attachment.cgi?id=25427" name="attach_25427" title="reproducer">attachment 25427</a> <a href="attachment.cgi?id=25427&action=edit" title="reproducer">[details]</a></span>
reproducer
In the attached testcase, LoopLoadElim unconditionally asks LoopVersioning to
add a runtime check, assuming that the check is optional. Unfortunately,
LoopVersioning will assert if the check is not needed. Should the assert just
be changed to return silently?
opt -loop-load-elim fail.ll
opt: llvm/llvm/lib/Transforms/Utils/LoopVersioning.cpp:88: void
llvm::LoopVersioning::versionLoop(const
llvm::SmallVectorImpl<llvm::Instruction*>&): Assertion `RuntimeCheck && "called
even though we don't need " "any runtime checks"' failed.
...
10 0x00007f989b41a607 llvm::LoopVersioning::versionLoop()
llvm/llvm/include/llvm/Transforms/Utils/LoopVersioning.h:63:0
#11 0x00007f989b416441 (anonymous
namespace)::LoadEliminationForLoop::processLoop()
llvm/llvm/lib/Transforms/Scalar/LoopLoadElimination.cpp:575:0
#12 0x00007f989b416899 eliminateLoadsAcrossLoops(llvm::Function&,
llvm::LoopInfo&, llvm::DominatorTree&, llvm::BlockFrequencyInfo*,
llvm::ProfileSummaryInfo*, llvm::ScalarEvolution*, llvm::AssumptionCache*,
llvm::function_ref<llvm::LoopAccessInfo const& (llvm::Loop&)>)
llvm/llvm/lib/Transforms/Scalar/LoopLoadElimination.cpp:637:0</pre>
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