On 02/03/2010 05:39 AM, Wu Fengguang wrote: > >> (I wonder if it could have used __builtin_popcount) >> >> (I wonder which gcc versions support __builtin_popcount) > I think 4.0 or later, but it often generates calls to libgcc, which would mean adding libgcc functions to the kernel (which some arches already do.) > This is how Jamie Lokier first recommended it to me: > > Checked GCC 3.4.3 / 4.1 / 4.4: It expands as a compile-time > constant if the argument is a compile-time constant, so can be > used in BUILD_BUG_ON() and even for array sizes etc. > > Is there an official lowest GCC version that Linux supports? 3.4, I believe. -hpa -- H. Peter Anvin, Intel Open Source Technology Center I work for Intel. I don't speak on their behalf. -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
