[clang] [llvm] [HLSL] Implement the `reflect` HLSL function (PR #122992)

[Finn Plummer via llvm-commits]

================
@@ -0,0 +1,33 @@
+; RUN: llc -O0 -mtriple=spirv-unknown-unknown %s -o - | FileCheck %s
----------------
inbelic wrote:

Out of curiousity, what happens when we use the triple `-mtriple=spirv32-unknown-unknown`? This should change the environment to be `OpenCL`, will it fail because there isn't a CL equivalent?

https://github.com/llvm/llvm-project/pull/122992