<table border="1" cellspacing="0" cellpadding="8">
<tr>
<th>Issue</th>
<td>
<a href=https://github.com/llvm/llvm-project/issues/99134>99134</a>
</td>
</tr>
<tr>
<th>Summary</th>
<td>
Implement the `length` HLSL Function
</td>
</tr>
<tr>
<th>Labels</th>
<td>
metabug,
backend:DirectX,
HLSL,
backend:SPIR-V,
bot:HLSL
</td>
</tr>
<tr>
<th>Assignees</th>
<td>
</td>
</tr>
<tr>
<th>Reporter</th>
<td>
farzonl
</td>
</tr>
</table>
<pre>
- [ ] Implement `length` clang builtin,
- [ ] Link `length` clang builtin with `hlsl_intrinsics.h`
- [ ] Add sema checks for `length` to `CheckHLSLBuiltinFunctionCall` in `SemaChecking.cpp`
- [ ] Add codegen for `length` to `EmitHLSLBuiltinExpr` in `CGBuiltin.cpp`
- [ ] Add codegen tests to `clang/test/CodeGenHLSL/builtins/length.hlsl`
- [ ] Add sema tests to `clang/test/SemaHLSL/BuiltIns/length-errors.hlsl`
- [ ] Create the `int_dx_length` intrinsic in `IntrinsicsDirectX.td`
- [ ] Create the `DXILOpMapping` of `int_dx_length` to `24` in `DXIL.td`
- [ ] Create the `length.ll` and `length_errors.ll` tests in `llvm/test/CodeGen/DirectX/`
- [ ] Create the `int_spv_length` intrinsic in `IntrinsicsSPIRV.td`
- [ ] In SPIRVInstructionSelector.cpp create the `length` lowering and map it to `int_spv_length` in `SPIRVInstructionSelector::selectIntrinsic`.
- [ ] Create SPIR-V backend test case in `llvm/test/CodeGen/SPIRV/hlsl-intrinsics/length.ll`
## DirectX
| DXIL Opcode | DXIL OpName | Shader Model | Shader Stages |
| ----------- | ----------- | ------------ | ------------- |
| 24 | Sqrt | 6.0 | () |
## SPIR-V
# Length:
## Description:
**Length**
Result is the length of vector *x*, i.e., sqrt(*x* \[0\] <sup>2</sup> +
*x* \[1\] <sup>2</sup> + …).
The operand *x* must be a scalar or vector whose component type is
floating-point.
*Result Type* must be a scalar of the same type as the component type of
*x*.
<table>
<colgroup>
<col style="width: 20%" />
<col style="width: 20%" />
<col style="width: 20%" />
<col style="width: 20%" />
<col style="width: 20%" />
</colgroup>
<thead>
<tr>
<th>Number</th>
<th>Operand 1</th>
<th>Operand 2</th>
<th>Operand 3</th>
<th>Operand 4</th>
</tr>
</thead>
<tbody>
<tr>
<td class="tableblock halign-left valign-top"><p>66</p></td>
<td
class="tableblock halign-left valign-top"><p><em><id></em><br />
<em>x</em></p></td>
<td></td>
<td></td>
<td></td>
</tr>
</tbody>
</table>
## Test Case(s)
### Example 1
```hlsl
//dxc length_test.hlsl -T lib_6_8 -enable-16bit-types -O0
export float fn(float4 p1) {
return length(p1);
}
```
## HLSL:
Returns the length of the specified floating-point vector.
| *ret* length(*x*) |
|-------------------|
## Parameters
| Item | Description |
|--------------------------------------------------------|-------------------------------------------------|
| <span id="x"></span><span id="X"></span>*x*<br/> | The specified floating-point vector.<br/> |
## Return Value
A floating-point scalar that represents the length of the *x* parameter.
## Type Description
| Name | [**Template Type**](https://github.com/MicrosoftDocs/win32/blob/docs/desktop-src//direct3dhlsl/dx-graphics-hlsl-intrinsic-functions.md) | [**Component Type**](https://github.com/MicrosoftDocs/win32/blob/docs/desktop-src//direct3dhlsl/dx-graphics-hlsl-intrinsic-functions.md) | Size |
|-------|-------------------------------------------------------------------------------------|----------------------------------------------------------------|------|
| *x* | [**vector**](https://github.com/MicrosoftDocs/win32/blob/docs/desktop-src//direct3dhlsl/dx-graphics-hlsl-intrinsic-functions.md) | [**float**](/windows/desktop/WinProg/windows-data-types) | any |
| *ret* | [**scalar**](https://github.com/MicrosoftDocs/win32/blob/docs/desktop-src//direct3dhlsl/dx-graphics-hlsl-intrinsic-functions.md) | [**float**](/windows/desktop/WinProg/windows-data-types) | 1 |
## Minimum Shader Model
This function is supported in the following shader models.
| Shader Model | Supported |
|------------------------------------------------------------------------------------|---------------------|
| [Shader Model 2 (DirectX HLSL)](https://github.com/MicrosoftDocs/win32/blob/docs/desktop-src//direct3dhlsl/dx-graphics-hlsl-sm2.md) and higher shader models | yes |
| [Shader Model 1 (DirectX HLSL)](https://github.com/MicrosoftDocs/win32/blob/docs/desktop-src//direct3dhlsl/dx-graphics-hlsl-sm1.md) | yes (vs\_1\_1 only) |
## See also
<dl> <dt>
[**Intrinsic Functions (DirectX HLSL)**](https://github.com/MicrosoftDocs/win32/blob/docs/desktop-src//direct3dhlsl/dx-graphics-hlsl-intrinsic-functions.md)
</dt> </dl>
</pre>
<img width="1px" height="1px" alt="" src="http://email.email.llvm.org/o/eJzsGdtu2zj2a-gXQoZM2a794AdHjmcDtNOiCbp9C2jpWOKWIjUknct8_eKQsi6x42SnA2wXWMOIxXPIc79R4daKQgGsyOyKzDYjfnClNqs9N39qJUc7nT-vIkpmV5TMNvSmqiVUoBwl81iCKlxJ5jHNJFcF3R2EdEIRlpJ43Z35KNSPC9vpo3Al4ktp5b1QzghlRWbHuHVAaJ3n1ELFaVZC9sPSvTZDuk7jOkXsPz7efrwKDLYHlTmhVcqlxF1C4a5bqLjfKVQxzur6HLNM51CAeo3RdSVcj8_1U206-ulvDfgt4g6ssw1FbxjCtggjbJvqHH4DhTwI2zb2soRtgyRjtNirRrpAF3VviHohb3pEIzBGG3uWdmqAO6CuBCQqlLvPn-47q7S-a0xw0_pyIwxk7vvY5ZdJbr7ffPxcf-J1LVSBJPX-LCenKcLZtLM3Hr1Mv3PhOAQCV3kHu2_0DqhgvEBZyofqxCeEbRulCNu-bSdbP7zLULdfbr5-O6PGjaIedaOsMwcfzrcgIXPaYHzRbMCx4yT1IxihCq9rxWtKhWti4pxYPjFe4UOSNUnW1q9agck8Hp9THYlE3-iOZz9A5d6cNOMW3jCp503YFoMv6kpBF_GyiUn8soSwhB69EGAfUoqBQD_XmF60t_6dV2F9W_IcDP2kc5B9wK3jBViENISi7kPfWJ8Coh4hNg18_jDOP8zHsf8lbEHY8rix1SjYrgXRj8FByXqoN9jMiBo91KAYfpvN_plSEoc_X8EepKPC-ggJtsTcevCepYStn_yRlIoxjPHX_mGcl89jKJmlZHYV-58NJUlqDzVJrhlJUsK2YUEJuwpy9I5M3jxCyTUji5is54Qtx53MdyVQXYPxWdrQrA7W0R1QTm3GJTdUm6MOj6W2QDNd1Vphf3LPNVBhSbzeS82dUEVUa6FcjwNhR8PcPddwnv7eW8xi8HiKPJjwBR-97xQfN25KUsd3EkhyHVaZloXRXu0WQK17xi0bwtijyL2XKYsJmxHGKFaW_-XNhG1PlHYl8LxbmR6CJNe_H6odmHDUA3q4z00sTC6j2WV0chk9PUHjygxWQw1wQDqrT45jjrXBUD4UdlJnP2jJpShUJGHv6EN4dromjOHRJEVTzeeBVR1AyLTHMSfx-i-TJkkKFf6yuXQkuRI5YfMCnwKjgEzSnRm40oOfhlsuCPiT0FObD6yMgF5qxcPCeIe9JuUWCFtYwpYB6ZM-7MBN108cJ1k6Qew8Dl8_8iCdLWHb_ClrCuU9tik_D9Hojkqxu5_fL2gECmWIJvOdcBFWAUujz01vgqdaG0d95aF7RdjCP05pPQkV_8rXIEoNuINRDSPCFh6PzsDOsekL1ynoJ7djN_jqCbys675m1ZCJvYCcDgtgUzDHA9P5brQ24LAKttK0fWHZdbPo9NM1sNbUnbRfuOEVODD2JcMbBxX9zz--p3fN771nXpX-XZ-_crQbALD51VxRkYeUfWpTEjthzVVYDPZ8P7en8QemZ8hOb42793h7eOZ1f4WAot-4PEBArF-SbHqjK7mjBmoDFpQ7F4LHtl0fY2A8zFRsnf055kWA-JEtTEqzqzDS3EFVSxwwm46N39mGsEXpXG0xK3zyFsKVh9040zhlfhKZ0Vbv3Ub7UfJRqIThfUrqHSZ6gOZgfzhdR9ZkTQHwg2WS-6qA9SAqDK9LkdloOJ5G--aCacdVjrnyety2eqTt_PArK-KnVvEnnOTPT2TSWynzt5HopV8Thi98EDLjV7Z9K6pPwL6kQYJcP_a4Erb9p1BfjC46bJRzx0N3ej0yPS-unnt1stcNBoKE1P-_zYLNJr3ecr6afhJKVIdqcOkMG-5KYelRAbyZ2UONQwPkeEfG6rnXUupHvLzbcLrC0_akcQ8utH_Px5Nt5RnAf66PvitzT-HHoJxdDZTF68aieQEQxiK2_G9Fpa1YE4V4jyhFUYIZOs5b9RnsOWu_ouDkl1JwcrG_NWGDChK2eLBklt5P_B-qlXwevuk4kyq3AJRLq9vrcy79sJKkuesm_WN2t2-g6PH1rj1nq1-zULXXGK8ZbZ5R3VG-SvJlsuQjWE0-sMlktlxOk1G5-pBNcx7HC5glcQIJ7Ng8S5Ywn8XT6ZTt4pFYsZhN4w-T-WQ5W8bJeLmE3Xw5zfb5ni1nOSfTGCou5FjKh2qsTTES1h5gtVxOkulI8h1I6_8JwFgFju8OBU6gLCWMNa_xSLJu33k2mGDnk23NK6wWoR1J1se9s83IrFCIaHcoLJnGUlhnO7GccBJW3X8aTl5qIqHW7aODkasLvm1eNXp-tdH_gswRtvWqo1OD9g8r9u8AAAD___M3G4E">