Re: [Discuss-gnuradio] MacOS, AVX, GCC, and LLVM

[Josh Blum]

> 
> Note that I'm compiling on a Sandy Bridge Intel processor, so Altivec
> (PPC), NEON (ARM), and float-ABI (ARM?) aren't available. Also, LLVM
> 3.0 doesn't support -mpopcnt, and apparently doesn't support
> -munsafe_math_optimizations. And yet, the detections are showing
> "Success". Sure enough, when I "make", volk bombs out with:
> 
> cc1: error: unrecognized command line option "-mfpu=neon" cc1: error:
> unrecognized command line option "-mfloat-abi=softfp"
> 
OK so, thats a pretty thorough analysis of the issue. I guess there
there is question of how to fix/who to blame:

1) cmake is at fault, and that patch needs to be in there

2) clang is at fault and should error/not warn.

Is there a clang flag to force unknown flags to become errors?
I think you can just pass another flag to CHECK_CXX_COMPILER_FLAG along
with the one being check.

And if thats not possible we could switch to CHECK_CXX_SOURCE_COMPILES
to help with the flag tests.

3) volk has a way to specify compiler specific flags. But its probably
wrong to use this if clang is using GCC flags and reporting as GNU.
http://gnuradio.org/cgit/gnuradio.git/tree/volk/gen/archs.xml

-Josh