<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/127512>127512</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            [HLSL] Misleading builtin diagnostics
        </td>
    </tr>

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

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

    <tr>
      <th>Reporter</th>
      <td>
          llvm-beanz
      </td>
    </tr>
</table>

<pre>
    Many of the HLSL builtins are reporting diagnostics using `err_typecheck_convert_incompatible`, which produces diagnostics of the form:
`error: passing <type1> to parameter of incompatible type <type2>`. This diagnostic strongly implies the usage of the builtin requires a specific type, which is not the case. For example see the `__builtin_hlsl_cross` intrinsic which is valid for 16 and 32-bit floating point types and vectors of such type.


```hlsl
export int4 fn(int4 x, int4 y) {
    return __builtin_hlsl_cross(x, y);
}

export int16_t4 fn(int16_t4 x, int16_t4 y) {
    return __builtin_hlsl_cross(x, y);
}
```
[Compiler Explorer](https://godbolt.org/z/79hMPMdTT)

Diagnostics:
```
<source>:2:33: error: passing 'int4' (aka 'vector<int, 4>') to parameter of incompatible type '__attribute__((__vector_size__(4 * sizeof(float)))) float' (vector of 4 'float' values)
    2 |     return __builtin_hlsl_cross(x, y);
      | ^
<source>:6:33: error: passing 'int16_t4' (aka 'vector<int16_t, 4>') to parameter of incompatible type '__attribute__((__vector_size__(4 * sizeof(float)))) float' (vector of 4 'float' values)
    6 |     return __builtin_hlsl_cross(x, y);
      | ^
```

These diagnostics strongly indicate to a user that you must call the builtin with a float4.
</pre>
<img width="1" height="1" alt="" src="http://email.email.llvm.org/o/eJzUVc2O4zYTfJr2pTGGROrPBx089hjfYQf4gMxdoKi2xSwlKiTlHc_TB6TstSebIAmwlwACLJKqru7qMls4p04jUQ35M-T7lZh9b2yt9Xl4akmMH6vWdJf6VYwXNEf0PeH_vvzyBdtZaa9Gh8ISWpqM9Wo8YafEaTTOK-lwdmEHioSsbfxlItmT_NpIM57J-kaN0gyT8KrVBEUCbIffeiV7nKzpZknuU7Ar99HYAfgWku0S11jgW5xCFYGL7wJPCvwFvcFJWDGQJxvQj3QYvrp9zYC_QJGs8a1Xj5zovDXjSV9QDZNW5GICsxMnumVzFQEt_TYrSw4FuomkOioZKe41KYej8REkhaM1HoxFehfDpAkdUTyBImmaa8ym10430hrnoEhQjd6q0Sl5j3cWWnVBEEwLFGOHnD21yuNRGxF7MRk1-piHi-dnkt7YKKWbZR9P1kHJ5Krn8gRiSLb0HnoaiDM8jsCq-PYeSopvF2AbhPIZki0ioiU_2xH_NH9WRVhAAA8AKPcL6Z0kLZoHomV1I1tWP4HwVmJ4z593ZpiUJosv75M2lizke2BV7_3kgsfYAdjhZLrWaL829gTs8AHsUG761_-_dm9vIXqsYn_36Xdv3on4zpnZSgo241sGfMt5MO2P7mVlUBZYicAq8VWEnaVpwHdq9KGmLIRhZdDiHziclU0jvLeqnT01DbAKWNU0S9DGqY9lM0NgWwxLcwRWRQeF6m4PXndiYgs4EAZY-f3oLPRMbhElNIghlDv8162KiAiF_OVH_Yq_0y-a5a81DMf_LR2Ln6TjoyeT7VtPjj7dsPfrbuyUFJ6CMAJnRxZ9LzxezIzD7DxKofWn---b8j2Kpbpsvepq3m34RqyoTku-qZIy21SrvubUsU0hBWddmhOlLc-7LOsScSzSI8vylapZwvKEpWWa5ymv1mWXp4UokjLLuk1RbCBLaBBKr8N8Cv_JlXJupjplZZ6ylRYtaRdHGWNhTAFjYajd5tl8cpAlWjnv7hG88jqOvwjI9_iqnCbRBUvdCnzQaTVbXf_hjlC-n9u1NAOwQ4h7_XmarPmVpAd2iGk6YIdrpuea_R4AAP__cFBfJw">