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<base href="https://llvm.org/bugs/" />
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<body><table border="1" cellspacing="0" cellpadding="8">
<tr>
<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW --- - miscompile of % in loop"
href="https://llvm.org/bugs/show_bug.cgi?id=23011">23011</a>
</td>
</tr>
<tr>
<th>Summary</th>
<td>miscompile of % in loop
</td>
</tr>
<tr>
<th>Product</th>
<td>clang
</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>
<tr>
<th>Status</th>
<td>NEW
</td>
</tr>
<tr>
<th>Severity</th>
<td>normal
</td>
</tr>
<tr>
<th>Priority</th>
<td>P
</td>
</tr>
<tr>
<th>Component</th>
<td>-New Bugs
</td>
</tr>
<tr>
<th>Assignee</th>
<td>unassignedclangbugs@nondot.org
</td>
</tr>
<tr>
<th>Reporter</th>
<td>nlewycky@google.com
</td>
</tr>
<tr>
<th>CC</th>
<td>llvmbugs@cs.uiuc.edu
</td>
</tr>
<tr>
<th>Classification</th>
<td>Unclassified
</td>
</tr></table>
<p>
<div>
<pre>$ clang++ -v
clang version 3.7.0 (trunk 233044)
Target: x86_64-unknown-linux-gnu
Testcase:
#include <stdio.h>
#include <stdlib.h>
#include <string>
using namespace std;
int main(int argc, char **argv) {
int r = 2;
bool ok = true;
while (ok) {
string ab;
for (int i = 0; i < r % 3; i++) {
ab += "ab";
}
printf("%d %s\n", r, ab.c_str());
r++;
ok = (r < 3);
}
}
nlewycky@ducttape:~$ clang++ -O2 a.cc -o a
nlewycky@ducttape:~$ ./a
2 ab
nlewycky@ducttape:~$ clang++ a.cc -o a
nlewycky@ducttape:~$ ./a
2 abab
The -O0 result is correct.</pre>
</div>
</p>
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