[clang] [llvm] [CodeGen][i386] Move -mregparm storage earlier and fix Runtime calls (PR #89707)

[Kees Cook via llvm-commits]

================
@@ -4781,6 +4782,7 @@ CodeGenModule::CreateRuntimeFunction(llvm::FunctionType *FTy, StringRef Name,
         }
       }
       setDSOLocal(F);
+      markRegisterParameterAttributes(F);
----------------
kees wrote:

I was trying to basically duplicate what was already done for the libcall functions. What is gained by using CGFunctionInfo? (Things already work as-is -- though generally it does looks like -mregparm support is kinda ad-hoc.)

https://github.com/llvm/llvm-project/pull/89707