AVX-512 detection?

[NAThompson]

The file

boost/predef/hardware/simd/x86.h

has macros for detection of AVX and AVX-2 instructions, but not AVX-512.

Could it be added? Or will it be too much trouble since AVX-512 is not a monolithic instruction set?

[grafikrobot]

It's possible, and there is the MIC detection which is AVX-512. Is MIC the only cpu which implements AVX-512? But yes, the problem would be that in the current arrangement it would not be possible to define the individual subsets. It would have to be a single version number to identify it. Perhaps it could be an alternate/alias to MIC? @jfalcou and @ccharly what do you think?

[jfalcou]

My stance on this matter as I tried to implement that in SPY :

• Have a AVX512 detection macro ghat basically means you have 512 bits simd register
• have a boolean macro for each sub system because avx512F does not mean Avx512dq is here

Alternatively, we could have a version number for avx like 50000 and use bit field in the lower bits to mask tets each subsystem. This means maybe more macro