<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/60685>60685</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            Missed Optimization: Superfluous Addressing on Data Load
        </td>
    </tr>

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

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

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

<pre>
    Consider the following simple code (which converts a hex digit character, case-insensitive, to an `int`):
```cpp
int hexchar_to_int(char hexchar) {
        constexpr static unsigned char const data[] = {
                255, 10,11,12,13,14,15, 255,255,255,255,255,255,255,255,255, 0,1,2,3,4,5,6,7,8,9
        };
        return data[ hexchar & 0b00011111 ];
}
```
GCC compiles this to:
```as
hexchar_to_int_table(char):
        and     edi, 31
 movzx   eax, BYTE PTR hexchar_to_int(char)::data[rdi]
 ret
```

However, Clang has an extra instruction:
```as
hexchar_to_int(char):
        and     edi, 31
 lea     rax, [rip + hexchar_to_int(char)::data]
        movzx eax, byte ptr [rdi + rax]
        ret
```

I believe GCC's output is strictly superior.
</pre>
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