<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/162360>162360</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            [CIR] Upstream pointer subtraction handling
        </td>
    </tr>

    <tr>
      <th>Labels</th>
      <td>
            ClangIR
      </td>
    </tr>

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

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

<pre>
    ### Overview
Upstream support for subtracting pointer values using the `cir.ptr_diff` operation. This will also require upstreaming the code to lower `cir.ptr_diff` to LLVM IR.

### Suggested minimal test case
```
unsigned long long test_ptr_diff(int *a, int* b) {
  return a - b;
}
```

### Existing incubator tests
clang/test/CIR/CodeGen/ptrdiff.c
clang/test/CIR/CodeGen/ptrdiff.cpp
</pre>
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