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<base href="https://bugs.llvm.org/">
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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - Incorrect result with -march=skx -O0 -m32"
href="https://bugs.llvm.org/show_bug.cgi?id=32241">32241</a>
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<th>Summary</th>
<td>Incorrect result with -march=skx -O0 -m32
</td>
</tr>
<tr>
<th>Product</th>
<td>new-bugs
</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>enhancement
</td>
</tr>
<tr>
<th>Priority</th>
<td>P
</td>
</tr>
<tr>
<th>Component</th>
<td>new bugs
</td>
</tr>
<tr>
<th>Assignee</th>
<td>unassignedbugs@nondot.org
</td>
</tr>
<tr>
<th>Reporter</th>
<td>Vsevolod.Livinskij@frtk.ru
</td>
</tr>
<tr>
<th>CC</th>
<td>llvm-bugs@lists.llvm.org
</td>
</tr></table>
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<pre>Created <span class=""><a href="attachment.cgi?id=18082" name="attach_18082" title="Reproducer.">attachment 18082</a> <a href="attachment.cgi?id=18082&action=edit" title="Reproducer.">[details]</a></span>
Reproducer.
Clang generates incorrect code with -m32 -O0 -march=skx options (same problem
for knl). Everything works fine with -m64 and other optimizations levels.
Reproducer:
#include <iostream>
int main () {
unsigned short aa = 10959;
unsigned short bb = 50038;
short cc = 19417;
bb = ~(aa < (cc || 0)) || 0;
std::cout << bb << std::endl;
return 0;
}
<span class="quote">>$ clang++ -m32 -w -O0 -march=skx repr.cpp ; sde -skx -- ./a.out</span >
0
<span class="quote">>$ clang++ -m32 -w -O0 repr.cpp ; ./a.out</span >
1
LLVM version:
clang version 5.0.0 (trunk 297270)
Target: x86_64-unknown-linux-gnu
Thread model: posix
InstalledDir: /home/vsevolod/workspace/llvm/bin-trunk/bin
Found candidate GCC installation: /usr/lib/gcc/i686-linux-gnu/5
Found candidate GCC installation: /usr/lib/gcc/i686-linux-gnu/5.4.0
Found candidate GCC installation: /usr/lib/gcc/i686-linux-gnu/6
Found candidate GCC installation: /usr/lib/gcc/i686-linux-gnu/6.0.0
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/5
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/5.4.0
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/6
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/6.0.0
Selected GCC installation: /usr/lib/gcc/x86_64-linux-gnu/5.4.0
Candidate multilib: .;@m64
Candidate multilib: 32;@m32
Candidate multilib: x32;@mx32
Selected multilib: .;@m64</pre>
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