Using --enable-avx512 fails on clang

[calebzulawski]

I am using clang 5.0.2 on Fedora 27, but I have also observed the issue on Xcode LLVM version 9.0.0 on macOS Sierra. This error does not present itself when using GCC. I am building version 3.3.8 configured with

./configure CC=clang --enable-sse2 --enable-fma --enable-avx --enable-avx-128-fma --enable-avx2 --enable-avx512

and built with make. This fails with the error:

Making all in avx512
make[4]: Entering directory '/home/czulawski/fftw-3.3.8/dft/simd/avx512'
make  all-am
make[5]: Entering directory '/home/czulawski/fftw-3.3.8/dft/simd/avx512'
/bin/sh ../../../libtool  --tag=CC   --mode=compile clang -DHAVE_CONFIG_H -I. -I../../..  -I ../../..   -O3 -fomit-frame-pointer -mtune=native -fstrict-aliasing -MT n1fv_2.lo -MD -MP -MF .deps/n1fv_2.Tpo -c -o n1fv_2.lo n1fv_2.c
libtool: compile:  clang -DHAVE_CONFIG_H -I. -I../../.. -I ../../.. -O3 -fomit-frame-pointer -mtune=native -fstrict-aliasing -MT n1fv_2.lo -MD -MP -MF .deps/n1fv_2.Tpo -c n1fv_2.c -o n1fv_2.o
In file included from n1fv_2.c:3:
In file included from ./../common/n1fv_2.c:35:
In file included from ../../../dft/simd/n1f.h:21:
../../../simd-support/simd-avx512.h:48:2: error: "compiling simd-avx512.h without avx-512f support"
#error "compiling simd-avx512.h without avx-512f support"
 ^
1 error generated.
make[5]: *** [Makefile:755: n1fv_2.lo] Error 1
make[5]: Leaving directory '/home/czulawski/fftw-3.3.8/dft/simd/avx512'
make[4]: *** [Makefile:512: all] Error 2
make[4]: Leaving directory '/home/czulawski/fftw-3.3.8/dft/simd/avx512'
make[3]: *** [Makefile:395: all-recursive] Error 1
make[3]: Leaving directory '/home/czulawski/fftw-3.3.8/dft/simd'
make[2]: *** [Makefile:502: all-recursive] Error 1
make[2]: Leaving directory '/home/czulawski/fftw-3.3.8/dft'
make[1]: *** [Makefile:708: all-recursive] Error 1
make[1]: Leaving directory '/home/czulawski/fftw-3.3.8'

[Zhivos]

Hello !
I'm on macOS Mojave and I have the same error message using CC=clang and CC=gcc..

[stevengj]

If someone with an AVX-512 machine could test #177 that would be appreciated.