<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/94594>94594</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            Clang can't compare 2 pointers into the same multidimensional array at compile time
        </td>
    </tr>

    <tr>
      <th>Labels</th>
      <td>
            clang:frontend,
            constexpr
      </td>
    </tr>

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

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

<pre>
    Take this example:

```c++
struct A {};
constexpr A a[3][3];
constexpr int diff2 = &a[1][3] - &a[0][0];
```

clang prints:
```console
<source>:7:15: error: constexpr variable 'diff2' must be initialized by a constant expression
    7 | constexpr int diff2 = &a[1][3] - &a[0][0];
      |               ^ ~~~~~~~~~~~~~~~~~~~
<source>:7:32: note: subtracted pointers are not elements of the same array
    7 | constexpr int diff2 = &a[1][3] - &a[0][0];
      |        
```

but all other compilers seem to accept this code just fine: https://godbolt.org/z/f7bGEThTT
</pre>
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