On Fri, Oct 21, 2016 at 5:31 PM, Jakub Jelinek <ja...@redhat.com> wrote: > On Fri, Oct 21, 2016 at 05:28:42PM +0200, Uros Bizjak wrote: >> On Fri, Oct 21, 2016 at 5:23 PM, Jakub Jelinek <ja...@redhat.com> wrote: >> > Hi! >> > >> > This patch adds folding for the new ia32 md builtins. >> > If they can be folded into constant, it is done in ix86_fold_builtin, >> > if they can fold to corresponding generic __builtin_c[lt]z* (which have >> > e.g. the advantage that VRP knows about what values it can have etc.), >> > it is done in gimple_fold_builtin target hook. >> >> Are you sure that there is no way zero will be passed to generic >> __builtin_c[lt]z? > > The patch only folds the ia32 specific builtins into __builtin_c[lt]z, if > the argument is known not to be 0 (from VRP). > That is the expr_not_equal_to call, which uses get_range_info under the > hood.
I was expecting this answer ;) Thanks, the patch is OK. (I'll backport this and my patch to gcc-6 early next week). Uros.
