<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/64886>64886</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            Infinite loop in MemCpyOpt/MemSSA
        </td>
    </tr>

    <tr>
      <th>Labels</th>
      <td>
            llvm:hang
      </td>
    </tr>

    <tr>
      <th>Assignees</th>
      <td>
      </td>
    </tr>

    <tr>
      <th>Reporter</th>
      <td>
          dcci
      </td>
    </tr>
</table>

<pre>
    ```
bash-3.2$ time xcrun ./clang -O1 unred.cpp -w
^C

real    0m12.947s
user    0m0.063s
sys     0m0.012s
bash-3.2$ time xcrun ./clang -O0 unred.cpp -w

real    0m0.265s
user    0m0.203s
sys     0m0.040s
bash-3.2$ cat unred.cpp
#define main wrap_main
#include <string.h>
   static char const * global39 = ((char const *)(""));
                            int main(int argc, char** argv){
                   {
 strncpy((((char*)(-1))-((char volatile )(1048576ULL))),global39,(*((unsigned long long*)(1))));
               }
                   void* i72 = memcpy(((void*)(((void*)(-1)))),((void const *)(((unsigned long*)(0)))),(((__int128_t)(4ULL))<<((long const )((-68719476736LL)))));
 return strncmp(((char const *)(1)),((char const *)("")),((unsigned long long)((511LL))));
                 }
#undef main
int main(int argc, char **argv) {
                 }
```
</pre>
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