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<base href="https://llvm.org/bugs/" />
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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW --- - Incorrect optimization of memmove in DSE"
href="https://llvm.org/bugs/show_bug.cgi?id=28013">28013</a>
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<th>Summary</th>
<td>Incorrect optimization of memmove in DSE
</td>
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<tr>
<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>Windows NT
</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>
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<th>Component</th>
<td>Scalar Optimizations
</td>
</tr>
<tr>
<th>Assignee</th>
<td>unassignedbugs@nondot.org
</td>
</tr>
<tr>
<th>Reporter</th>
<td>eli.friedman@gmail.com
</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>Testcase:
#include <string.h>
#include <stdlib.h>
void f(char *a, char *b) {
memmove(a, b, 10);
memmove(a, b, 10);
}
void (*ff)(char*,char*) = f;
int main() {
char x[20] = {1, 1};
ff(x, x+1);
if (x[0]) abort();
return 0;
}
Runs correctly with clang -O0, aborts with clang -O2.
The isPossibleSelfRead helper in DSE is wrong.
(Artificial testcase.)</pre>
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