Addresses PR comments.

Author: danbrown-amd

clang/lib/Headers/hlsl/hlsl_intrinsics.h

@@ -303,43 +303,6 @@ fmod(__detail::HLSL_FIXED_VECTOR<float, N> X,
   return __detail::fmod_vec_impl(X, Y);
 }
 
-//===----------------------------------------------------------------------===//
-// isnan builtins
-//===----------------------------------------------------------------------===//
-
-/// \fn bool isnan(T x)
-/// \brief Returns whether x is NaN or QNaN.
-/// \param x [in] A number or vector of numbers.
-///
-/// Return whether (each element of) x is NaN or QNaN.
-
-template <typename T>
-_HLSL_16BIT_AVAILABILITY(shadermodel, 6.2)
-const inline __detail::enable_if_t<
-    __detail::is_arithmetic<T>::Value && __detail::is_same<half, T>::value, T>
-isnan(T X) {
-  return __builtin_elementwise_isnan(X);
-}
-template <typename T>
-const inline __detail::enable_if_t<
-    __detail::is_arithmetic<T>::Value && __detail::is_same<float, T>::value, T>
-isnan(T X) {
-  return __builtin_elementwise_isnan(X);
-}
-
-template <int N>
-_HLSL_16BIT_AVAILABILITY(shadermodel, 6.2)
-const inline __detail::HLSL_FIXED_VECTOR<half, N>
-isnan(__detail::HLSL_FIXED_VECTOR<half, N> X) {
-  return __builtin_elementwise_isnan(X);
-}
-
-template <int N>
-const inline __detail::HLSL_FIXED_VECTOR<float, N>
-isnan(__detail::HLSL_FIXED_VECTOR<float, N> X) {
-  return __builtin_elementwise_isnan(X);
-}
-
 //===----------------------------------------------------------------------===//
 // ldexp builtins
 //===----------------------------------------------------------------------===//

llvm/lib/Target/DirectX/DXIL.td

@@ -424,6 +424,7 @@ def Saturate : DXILOp<7, unary> {
 
 def IsNaN : DXILOp<8, isSpecialFloat> {
   let Doc = "Determines if the specified value is NaN.";
+  let intrinsics = [IntrinSelect<int_dx_isnan>];
   let arguments = [OverloadTy];
   let result = Int1Ty;
   let overloads = [Overloads<DXIL1_0, [HalfTy, FloatTy]>];

llvm/lib/Target/DirectX/DXILIntrinsicExpansion.cpp

@@ -213,6 +213,7 @@ static bool isIntrinsicExpansion(Function &F) {
   case Intrinsic::dx_nclamp:
   case Intrinsic::dx_degrees:
   case Intrinsic::dx_isinf:
+  case Intrinsic::dx_isnan:
   case Intrinsic::dx_lerp:
   case Intrinsic::dx_normalize:
   case Intrinsic::dx_fdot:
@@ -1024,6 +1025,9 @@ static bool expandIntrinsic(Function &F, CallInst *Orig) {
   case Intrinsic::dx_isinf:
     Result = expand16BitIsInf(Orig);
     break;
+  case Intrinsic::dx_isnan:
+    Result = expand16BitIsInf(Orig);
+    break;
   case Intrinsic::dx_lerp:
     Result = expandLerpIntrinsic(Orig);
     break;

llvm/lib/Target/DirectX/DirectXTargetTransformInfo.cpp

@@ -48,6 +48,7 @@ bool DirectXTTIImpl::isTargetIntrinsicTriviallyScalarizable(
   case Intrinsic::dx_firstbituhigh:
   case Intrinsic::dx_frac:
   case Intrinsic::dx_isinf:
+  case Intrinsic::dx_isnan:
   case Intrinsic::dx_rsqrt:
   case Intrinsic::dx_saturate:
   case Intrinsic::dx_splitdouble: