[HLSL] reflect, distance, and length intrinsics are not restricting vector size

[farzonl]

llvm-project/clang/lib/Headers/hlsl/hlsl_intrinsics.h

Lines 2084 to 2093 in 556eb82

	template <int L>
	_HLSL_16BIT_AVAILABILITY(shadermodel, 6.2)
	const inline vector<half, L> reflect(vector<half, L> I, vector<half, L> N) {
	return __detail::reflect_vec_impl(I, N);
	}
	template <int L>
	const inline vector<float, L> reflect(vector<float, L> I, vector<float, L> N) {
	return __detail::reflect_vec_impl(I, N);
	}

llvm-project/clang/lib/Headers/hlsl/hlsl_intrinsics.h

Lines 1446 to 1454 in 556eb82

	template <int N>
	_HLSL_16BIT_AVAILABILITY(shadermodel, 6.2)
	const inline half length(vector<half, N> X) {
	return __detail::length_vec_impl(X);
	}
	template <int N> const inline float length(vector<float, N> X) {
	return __detail::length_vec_impl(X);
	}

llvm-project/clang/lib/Headers/hlsl/hlsl_intrinsics.h

Lines 933 to 942 in 556eb82

	template <int N>
	_HLSL_16BIT_AVAILABILITY(shadermodel, 6.2)
	const inline half distance(vector<half, N> X, vector<half, N> Y) {
	return __detail::distance_vec_impl(X, Y);
	}
	template <int N>
	const inline float distance(vector<float, N> X, vector<float, N> Y) {
	return __detail::distance_vec_impl(X, Y);
	}

The fix:
we need to exclude vec1s and limit to vec4. the apis need something similar to c++

 std::enable_if_t<(N > 1 && N <=4)

Long term we will want to support long vectors we may want to do those like so

_HLSL_AVAILABILITY(shadermodel, 6.9)
template <int N, typename = std::enable_if_t<(N >4)>>

For this ticket though we will only restrict the vector range.

Obviously std can't work maybe we can do something like:

template <int N>
_HLSL_16BIT_AVAILABILITY(shadermodel, 6.2)
const inline __detail::enable_if_t<(N > 1 && N <= 4),half>
distance(vector<half, N> X, vector<half, N> Y) {
  return __detail::distance_vec_impl(X, Y);
}

template <int N>
const inline __detail::enable_if_t<(N > 1 && N <= 4),float>
distance(vector<float, N> X, vector<float, N> Y) {
  return __detail::distance_vec_impl(X, Y);
}

template <int N>
_HLSL_16BIT_AVAILABILITY(shadermodel, 6.2)
const inline __detail::enable_if_t<(N > 1 && N <= 4),half>
length(vector<half, N> X) {
  return __detail::length_vec_impl(X);
}

template <int N>
const inline __detail::enable_if_t<(N > 1 && N <= 4),float>
length(vector<float, N> X) {
  return __detail::length_vec_impl(X);
}

template <int L>
_HLSL_16BIT_AVAILABILITY(shadermodel, 6.2)
const inline __detail::enable_if_t<(L > 1 && L <= 4),vector<half, L>>
reflect(vector<half, L> I, vector<half, L> N) {
  return __detail::reflect_vec_impl(I, N);
}

template <int L>
const inline __detail::enable_if_t<(L > 1 && L <= 4),vector<float, L>>
reflect(vector<float, L> I, vector<float, L> N) {
  return __detail::reflect_vec_impl(I, N);
}

Will likely need to see what other options are to restrict vector ranges.