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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW --- - LLC: Frame Pointer Elim. optimization causes a stack crash on Sandybridge."
href="https://llvm.org/bugs/show_bug.cgi?id=29037">29037</a>
</td>
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<th>Summary</th>
<td>LLC: Frame Pointer Elim. optimization causes a stack crash on Sandybridge.
</td>
</tr>
<tr>
<th>Product</th>
<td>tools
</td>
</tr>
<tr>
<th>Version</th>
<td>trunk
</td>
</tr>
<tr>
<th>Hardware</th>
<td>PC
</td>
</tr>
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<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>llc
</td>
</tr>
<tr>
<th>Assignee</th>
<td>unassignedbugs@nondot.org
</td>
</tr>
<tr>
<th>Reporter</th>
<td>shishpanov2010@yandex.ru
</td>
</tr>
<tr>
<th>CC</th>
<td>llvm-bugs@lists.llvm.org
</td>
</tr>
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<th>Classification</th>
<td>Unclassified
</td>
</tr></table>
<p>
<div>
<pre>Created <span class=""><a href="attachment.cgi?id=16986" name="attach_16986" title="Source IR">attachment 16986</a> <a href="attachment.cgi?id=16986&action=edit" title="Source IR">[details]</a></span>
Source IR
Launch commands:
llc -mcpu=sandybridge input.ll -o output.asm -O1 ;
clang++ test_static.cpp output.asm -o output.run ;
./output.run
If I run LLC with -O0 instead of -O1 or run it with -disable-fp-elim, the
function f_fu() works properly. If I run it with -O1, I have seg. fault.
As I can see, the problem is in the last VPEXTRD instruction in f_fu(), which
overrides and damages the pointer's value for the final result on the stack. In
addition, if I skip " TFI.orderFrameObjects(Fn, ObjectsToAllocate);" in
lib/CodeGen/PrologEpilogInserter.cpp:calculateFrameObjectOffsets(MachineFunction
&Fn) with -O1 only, then it works.
LLVM rev. 277592.</pre>
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