Please fix build system to allow building without SSE instructions

[xctan]

I'm trying to build this package from source code for Arch Linux RISC-V port. But I encountered errors like unrecognized command-line option '-msse'. This problem isn't disappeared when I changed BUILD_SSE from ON to OFF. After searching the commit that introduced BUILD_SSE, I found that the commit 3410625 didn't completely resolve the problem. Even when -DBUILD_SSE=OFF is presented to cmake, it seems like src/avtk/CMakeLists.txt still inserts -msse -msse2 -mfpmath=sse into CMAKE_CXX_FLAGS.

Please provide additional checks for other architectures in src/avtk/CMakeLists.txt to fix this issue.

openAV-ArtyFX/src/avtk/CMakeLists.txt

Lines 57 to 63 in 9b147f2

	IF(NOT ${CMAKE_SYSTEM_PROCESSOR} MATCHES "arm")
	SET(CMAKE_C_FLAGS "-fPIC -msse -msse2 -mfpmath=sse -g") # -fsanitize=address
	SET(CMAKE_CXX_FLAGS "-fPIC -msse -msse2 -mfpmath=sse -g") # -fsanitize=address
	ELSE()
	SET(CMAKE_C_FLAGS "-fPIC -mfpu=neon -g")
	SET(CMAKE_CXX_FLAGS "-fPIC -mfpu=neon -g")
	ENDIF(NOT ${CMAKE_SYSTEM_PROCESSOR} MATCHES "arm")

[harryhaaren]

Hi,

Thanks for reporting. I don't have a RISC-V board/port to test on unfortunately, so its a little awkward to know what flags should be passed to the RISC-V compiler for SIMD support.

If you have the time would you propose the C_FLAGS to use, or even better, file a PR which makes the code changes required?

Regards, -Harry

[xctan]

Standard Extension for Packed-SIMD Instructions is still open as for now. So, I think -DBUILD_SSE=OFF should be able to turn off all SIMD flags as we don't have available SIMD instructions currently for rv64gc arch.

[harryhaaren]

Hi, as a new architecture, I would encourage the use of Meson build system instead of CMake. I'm actively moving all OpenAV projects to Meson for a while now - CMake is awkward and Meson is better in many ways.

Aside from that, current master branch seems to work as you describe, but use BUILD_SSE=0 not OFF.
The below commands do not show -msse compiler-flags here.

mkdir build
cd build
cmake .. -DBUILD_SSE=0
make VERBOSE=1