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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 - Clang produces incorrect code with -O2 and higher"
href="https://bugs.llvm.org/show_bug.cgi?id=32830">32830</a>
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<th>Summary</th>
<td>Clang produces incorrect code with -O2 and higher
</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=18373" name="attach_18373" title="Reproducer.">attachment 18373</a> <a href="attachment.cgi?id=18373&action=edit" title="Reproducer.">[details]</a></span>
Reproducer.
Reproducer:
<span class="quote">>$ cat repr.c </span >
extern const long int var_47;
extern const long int var_53;
extern const long long int var_58;
extern long int var_579;
void foo() {
var_579 = ((var_58 | var_53) ^ ~var_58) & (var_47 | ~var_58);
}
<span class="quote">>$ cat main.c </span >
#include <stdio.h>
extern void foo ();
const long int var_47 = 6664195969892517546L;
const long int var_53 = 1679594420099092216L;
const long long int var_58 = 1515497576132836640LL;
long int var_579 = -7475619439701949757L;
int main () {
foo ();
printf ("%ld\n", var_579);
return 0;
}
Error:
<span class="quote">>$ clang -O0 main.c repr.c; ./a.out </span >
-236191838907956185
<span class="quote">>$ clang -O2 main.c repr.c; ./a.out </span >
-5292815780869864331
LLVM version:
<span class="quote">>$ clang -vclang version 5.0.0 (trunk 301477)</span >
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
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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