Yes, that solved. the problem. I was using GCC 4.8 and I found in the GCC 4.9 release notes that it was addressed in that version. I tried with GCC 5.2 and it works just #include <x86intrin.h> and declare the function with __attribute__((target("bmi2"))). Thanks! On Thu, Aug 27, 2015 at 10:32 AM, Marc Glisse <marc.glisse@xxxxxxxx> wrote: > On Thu, 27 Aug 2015, Ruben Laguna wrote: > >> In order for the _bzhi_u32 intrinsic to be defined when including >> `x86intrinc.h` I need to compile with `-mbmi2` > > > Try again with a more recent version of gcc? > > -- > Marc Glisse -- /Rubén