On Thu, Nov 20, 2014 at 07:36:03PM +0300, Ilya Enkovich wrote: > Hi, > > MPX runtime checks some feature bits in order to check MPX is fully > supported. Runtime does it by cpuid calls but there is a > __builtin_cpu_supports which may be used for that. Unfortunately > currently it doesn't support required bits. Will it be OK to add them for > trunk?
I think using cpuid for that is just fine. __builtin_cpu_supports is for ISA additions users might actually want to version code for, MPX stuff, as the instructions are nops without hw support, are not something one would multi-version a function for. If anything, AVX512F and AVX512BW+VL might be good candidates for that, not MPX. Jakub