On Tue, Aug 26, 2025 at 09:24:04PM -0400, Yury Norov wrote: > On Tue, Aug 26, 2025 at 09:56:06AM -0700, Kees Cook wrote: > > On Tue, Aug 26, 2025 at 03:08:59PM +0200, Rasmus Villemoes wrote: > > > If __builtin_arc_fls() simply doesn't qualify for attr_const for > > > $reason, I think it would be good to have that documented in the commit > > > msg. If it does, I think a gcc ticket and link to that would be in order. > > > > I already sent the patch to fix it. :) > > > > https://gcc.gnu.org/pipermail/gcc-patches/2025-August/693273.html > > I'm OK taking the patch if it fixes real problem for you, but it looks > more like a GCC problem, right? Is Clang also affected?
Without it, KUnit testing of ffs/fls fails on arc. Clang is not affected. Even with the GCC fix landed, all older GCCs with still fail, and since it provides a improved code generation for arc, it seems worth it (compile-time-calculable values will be emitted instead of always running the arc instructions). > If, say, Clang is not affected, and you expect that newer GCC versions > will not be affected too, let's protect the new code with a proper > ifdefery, so that it will be easier to drop the workaround later? I think the codegen benefit is worth it as I have it. -- Kees Cook _______________________________________________ linux-snps-arc mailing list [email protected] http://lists.infradead.org/mailman/listinfo/linux-snps-arc
