[clang] Implement the `fmod` intrinsic (PR #130320)

[Farzon Lotfi via cfe-commits]

================
@@ -97,6 +97,31 @@ constexpr vector<T, L> reflect_vec_impl(vector<T, L> I, vector<T, L> N) {
 #endif
 }
 
+template <typename T>
+constexpr enable_if_t<is_same<float, T>::value || is_same<half, T>::value, T>
----------------
farzonl wrote:

move these changes to `clang/lib/Headers/hlsl/hlsl_intrinsic_helpers.h`. After @llvm-beanz  change: https://github.com/llvm/llvm-project/pull/129396/files#diff-f5dc7c12e2bb511ab1504961855fdd1e81dbeda43b8e3ee174819fb4a61c4acb these need to be in a seperate file.

https://github.com/llvm/llvm-project/pull/130320