[clang] [llvm] [HLSL] Adding HLSL `clip` function. (PR #114588)

[Finn Plummer via cfe-commits]

================
@@ -75,7 +75,9 @@ static const std::map<std::string, SPIRV::Extension::Extension>
         {"SPV_KHR_cooperative_matrix",
          SPIRV::Extension::Extension::SPV_KHR_cooperative_matrix},
         {"SPV_KHR_non_semantic_info",
-         SPIRV::Extension::Extension::SPV_KHR_non_semantic_info}};
+         SPIRV::Extension::Extension::SPV_KHR_non_semantic_info},
+        {"SPV_EXT_demote_to_helper_invocation",
----------------
inbelic wrote:

We could add a description of the extension in `llvm/docs/SPIRVUsage.rst`.

https://github.com/llvm/llvm-project/pull/114588