Fix feature detection for AVX512

Our AVX512 code was all gated behind checks for AVX512F, but also used a
couple intrinsics that are part of AVX512DQ. If someone built with
-mavx512f (ie certain Xeon chips before Skylake X), you would get
compile failures.

Now the checks also verify that __AVX512DQ__ is available. Note that the
runtime detection code was already testing for all of (F,DQ,CD,BW,VL),
so the skx:: version of the code will still only be used when it's safe
to do so.

Change-Id: Id3ebbf506c10eab469ee587f62a963a7272af04a
Reviewed-by: Herb Derby <>
Commit-Queue: Brian Osman <>
2 files changed