[clang] [HLSL] Implement support for HLSL intrinsic - select (PR #107129)

[Sarah Spall via cfe-commits]

================
@@ -1544,6 +1604,30 @@ bool SemaHLSL::CheckBuiltinFunctionCall(unsigned BuiltinID, CallExpr *TheCall) {
       return true;
     break;
   }
+  case Builtin::BI__builtin_hlsl_select: {
----------------
spall wrote:

I think it is slightly special. It is a template function, and the first argument must be either a bool or a vector of bools.  Both of those cases have slightly different checks; so I made a function for each. I don't believe any of the existing Check functions checked for the correct things; most of them require all args are the same type. 

https://github.com/llvm/llvm-project/pull/107129