2014-11-21 20:45 GMT+03:00 Jeff Law <l...@redhat.com>: > On 11/20/14 09:40, Jakub Jelinek wrote: >> >> 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. > > SOrry, I didn't know the __builtin_cpu_supports was really only ment for > user multi-versioning. In that case, it won't make any sense to put the MPX > stuff in there. > > Sorry for sending you down a wrong path Ilya.
It's OK, AVX guys will just transform this MPX patch into AVX512 one :) Ilya > > jeff