[clang] [llvm] Adding splitdouble HLSL function (PR #109331)

[Farzon Lotfi via cfe-commits]

================
@@ -85,4 +85,9 @@ def int_dx_rsqrt  : DefaultAttrsIntrinsic<[llvm_anyfloat_ty], [LLVMMatchType<0>]
 def int_dx_wave_is_first_lane : DefaultAttrsIntrinsic<[llvm_i1_ty], [], [IntrConvergent]>;
 def int_dx_sign : DefaultAttrsIntrinsic<[LLVMScalarOrSameVectorWidth<0, llvm_i32_ty>], [llvm_any_ty], [IntrNoMem]>;
 def int_dx_step : DefaultAttrsIntrinsic<[LLVMMatchType<0>], [llvm_anyfloat_ty, LLVMMatchType<0>], [IntrNoMem]>;
+
+def int_dx_splitdouble : DefaultAttrsIntrinsic<
+    [llvm_anyint_ty, LLVMMatchType<0>], 
+    [LLVMScalarOrSameVectorWidth<0, llvm_double_ty>], 
+    [IntrNoMem, IntrWillReturn]>;
----------------
farzonl wrote:

`DefaultAttrsIntrinsic` already has a `IntrWillReturn` attribute. 
```suggestion
def int_dx_splitdouble : DefaultAttrsIntrinsic<
    [llvm_anyint_ty, LLVMMatchType<0>], 
    [LLVMScalarOrSameVectorWidth<0, llvm_double_ty>], 
    [IntrNoMem]>;
```

https://github.com/llvm/llvm-project/pull/109331