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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - [Debuginfo] @llvm.dbg.value changes behaviour of "Speculatively execute instructions""
href="https://bugs.llvm.org/show_bug.cgi?id=40573">40573</a>
</td>
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<th>Summary</th>
<td>[Debuginfo] @llvm.dbg.value changes behaviour of "Speculatively execute instructions"
</td>
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<th>Product</th>
<td>libraries
</td>
</tr>
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<th>Version</th>
<td>trunk
</td>
</tr>
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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>
</tr>
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<th>Severity</th>
<td>enhancement
</td>
</tr>
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<th>Priority</th>
<td>P
</td>
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<th>Component</th>
<td>Scalar Optimizations
</td>
</tr>
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<th>Assignee</th>
<td>unassignedbugs@nondot.org
</td>
</tr>
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<th>Reporter</th>
<td>paulsson@linux.vnet.ibm.com
</td>
</tr>
<tr>
<th>CC</th>
<td>llvm-bugs@lists.llvm.org
</td>
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<p>
<div>
<pre>Created <span class=""><a href="attachment.cgi?id=21421" name="attach_21421" title="reduced testcase">attachment 21421</a> <a href="attachment.cgi?id=21421&action=edit" title="reduced testcase">[details]</a></span>
reduced testcase
Without the @llvm.dbg instruction in the test case, the fdiv instruction is
moved up in the CFG by
bin/opt -mtriple=systemz-unknown -mcpu=z13 -S tc_speculexe.ll
-speculative-execution
I suspect that this is also (as in <a class="bz_bug_link
bz_status_NEW "
title="NEW - [Debuginfo] @llvm.dbg.value in loop prevents optimization in LoopIdiomRecognize"
href="show_bug.cgi?id=40564">bug 40564</a>) related to counting instructions
in the block on the line
if (NotHoisted.size() > SpecExecMaxNotHoisted)
in SpeculativeExecution.cpp</pre>
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