AVX512 not working with MSVC compiler VS 17.12.1

[Martin Toeltsch]

Hi, 

first of all many, many thanks for all your effort!

We are currently porting our open source project DeepSkyStacker from Windows to (additionally) Linux and Mac/ARM. 

We have implemented the core routines for best performance with AVX2/AVX512 intrinsics.

We want to use Simde to support ARM on Mac.

But as soon as we include avx512.h like this:

#define SIMDE_ENABLE_NATIVE_ALIASES
#include "simde/x86/avx512.h"

the Microsoft compiler shows these errors:

1>C:\Users\mtoeltsch\dev\DSS\DeepSkyStackerKernel\simde\x86\avx512\types.h(622,25): error C2371: '__m512': redefinition; different basic types
1>(compiling source file '/avx.cpp')
1> C:\Program Files\Microsoft Visual Studio\2022\Community\VC\Tools\MSVC\14.42.34433\include\zmmintrin.h(47,61):
1> see declaration of '__m512'
1>C:\Users\mtoeltsch\dev\DSS\DeepSkyStackerKernel\simde\x86\avx512\types.h(623,26): error C2371: '__m512i': redefinition; different basic types
1>(compiling source file '/avx.cpp')

Note that we do not include zmmintrin.h or any other intrinsics header file. 

BTW: You get similar problems, if you do the same with the Compiler Explorer ( https://simde.netlify.app/godbolt/demo ).

Thanks, 

Martin