[clang] [HLSL] Add bounds checks for the hlsl vector arguments and return types (PR #130724)

[Farzon Lotfi via cfe-commits]

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@@ -89,23 +89,31 @@ void asuint(double4, out uint4, out uint4);
 /// \param X The X input value.
 /// \param Y The Y input value.
 
+template <typename T>
 _HLSL_16BIT_AVAILABILITY(shadermodel, 6.2)
-const inline half distance(half X, half Y) {
+const inline __detail::enable_if_t<__detail::is_arithmetic<T>::Value &&
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farzonl wrote:

Yeah I didn't want to templatize the scalar case, but what I found out was if I didn't then the vectors of any size would cast themselves down to scalars. The `is_arithmetic` here is to check the type coming in is already a scalar.

The annoying thing for this case was I needed to distinguish  the float and half scalar templates to be able to apply `_HLSL_16BIT_AVAILABILITY(shadermodel, 6.2)` and thats why the `is_same` stuff is here.

https://github.com/llvm/llvm-project/pull/130724