Hi everyone,

 

I tried to compile some program using neon optimization on odroid C2 with the following arguments in CMake :

IF(IS_ARM)
  SET(CMAKE_CXX_FLAGS_RELEASE "${CMAKE_CXX_FLAGS} -O3 -mfpu='neon' -march=armv8-a")

But gives me an error not recognizing the command -mfpu='neon' . 

 

Is there a way I give still activate this instruction optimization or should I give up NEON support for the moment ?

 

Thanks !

https://stackoverflow.com/questions/29851128/gcc-arm64-aarch64-unrecognized-command-line-option-mfpu-neon

Hi,

 

Thanks a lot for your answer. The code I try to compile was previously made for the Odroid C1, arch was defined as 

-march=armv7-a

I replaced it as 

-march=armv8-a

But I still have some gcc cc1plus error when I try to compile. Would you recommend to set any other stuff to compile it on the C2 ?

 

Thanks

But I still have some gcc cc1plus error when I try to compile. Would you recommend to set any other stuff to compile it on the C2 ?

If you are compiling with -O3 or -O2 flags then compiler should generate efficient enough code. Explicitly defining optimization parameters won't make noticeable difference in most cases, upgrading compiler version (i.e. GCC 4.9 to GCC 5.x or GCC 6.x) may make more difference.

 

For compiler errors - Google is your best friend, and if extra compiler parameters cause these errors, then you will have to use default options.