CMAKE_CXX_COMPILER_ARCHITECTURE_ID is empty even when passed to cmake in command line with -D

I passed -DCMAKE_CXX_COMPILER_ARCHITECTURE_ID=x64 in command line to cmake:

cmake ../ -DCMAKE_CXX_COMPILER_ARCHITECTURE_ID=x64

and in CMakeLists.txt I have the following lines:

message(STATUS "CMAKE_CXX_COMPILER_ARCHITECTURE_ID: ${CMAKE_CXX_COMPILER_ARCHITECTURE_ID}")

end it prints empty variable. If run cmake for second time it prints correct value.

Then I changed my CMakeLists.txt to the following:

message(STATUS "CMAKE_CXX_COMPILER_ARCHITECTURE_ID: ${CMAKE_CXX_COMPILER_ARCHITECTURE_ID}")
set (CMAKE_CXX_COMPILER_ARCHITECTURE_ID ${CMAKE_CXX_COMPILER_ARCHITECTURE_ID})
message(STATUS "CMAKE_CXX_COMPILER_ARCHITECTURE_ID: ${CMAKE_CXX_COMPILER_ARCHITECTURE_ID}")

remove the build directory and run cmake ../ -DCMAKE_CXX_COMPILER_ARCHITECTURE_ID=x64 and then:

-- CMAKE_CXX_COMPILER_ARCHITECTURE_ID: 
-- CMAKE_CXX_COMPILER_ARCHITECTURE_ID: x64

Also I added message in Modules/CMakeDetermineCXXCompiler.cmake

if(CMAKE_CXX_COMPILER_ARCHITECTURE_ID)
...
else()
   message(STATUS "empty CMAKE_CXX_COMPILER_ARCHITECTURE_ID")
endif()

and it is printed.

I tested with: cmake version 3.10.2 (on Ubuntu 18.04) and cmake version 3.12.3

Here is my CMakeLists.txt:

cmake_minimum_required(VERSION 3.5)

project(TestCxxArhId)

message(STATUS "CMAKE_CXX_COMPILER_ARCHITECTURE_ID: ${CMAKE_CXX_COMPILER_ARCHITECTURE_ID}")
#######   workaround CMAKE_CXX_COMPILER_ARCHITECTURE_ID to be set by command line
set (CMAKE_CXX_COMPILER_ARCHITECTURE_ID ${CMAKE_CXX_COMPILER_ARCHITECTURE_ID})
message(STATUS "CMAKE_CXX_COMPILER_ARCHITECTURE_ID: ${CMAKE_CXX_COMPILER_ARCHITECTURE_ID}")

SET(srcfiles main.cpp CACHE INTERNAL "" FORCE) # main.cpp -> just an empty main() function
add_executable(demo ${srcfiles})

Here is a simple main.cpp

int main() {}