arg_vars :: [(CmmActual, ForeignHint)]
         -> ([LlvmVar], LlvmStatements, [LlvmCmmDecl])
         -> LlvmM ([LlvmVar], LlvmStatements, [LlvmCmmDecl])

arg_vars [] (vars, stmts, tops)
  = return (vars, stmts, tops)
arg_vars :: [(CmmActual, ForeignHint)]
         -> ([LlvmVar], LlvmStatements, [LlvmCmmDecl])
         -> LlvmM ([LlvmVar], LlvmStatements, [LlvmCmmDecl])
arg_vars [] (vars, stmts, tops)
  = return (vars, stmts, tops)
arg_vars [] (vars, stmts, tops)
  = return (vars, stmts, tops)