[clang] [llvm] [HLSL] Move length support out of the DirectX Backend (PR #121611)

[Farzon Lotfi via cfe-commits]

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@@ -1297,27 +1297,16 @@ float4 lerp(float4, float4, float4);
 ///
 /// Length is based on the following formula: sqrt(x[0]^2 + x[1]^2 + ...).
 
-_HLSL_16BIT_AVAILABILITY(shadermodel, 6.2)
-_HLSL_BUILTIN_ALIAS(__builtin_hlsl_length)
-half length(half);
-_HLSL_16BIT_AVAILABILITY(shadermodel, 6.2)
-_HLSL_BUILTIN_ALIAS(__builtin_hlsl_length)
-half length(half2);
-_HLSL_16BIT_AVAILABILITY(shadermodel, 6.2)
-_HLSL_BUILTIN_ALIAS(__builtin_hlsl_length)
-half length(half3);
-_HLSL_16BIT_AVAILABILITY(shadermodel, 6.2)
-_HLSL_BUILTIN_ALIAS(__builtin_hlsl_length)
-half length(half4);
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farzonl wrote:

sorry bad merge its supposed to be above the half versions in this file. 

https://github.com/llvm/llvm-project/pull/121611