Richard Henderson <r...@twiddle.net> writes: > On 02/25/2015 02:45 AM, Markus Armbruster wrote: >> return 0x8000000000000000u >> (clz64(value - 1) - 1); > > I realize this was weeks ago, but it would certainly be preferable to shift a > small constant left than a large constant right. > > Most RISC machines can't form 0x8000000000000000ull without loading 1 and then > left shifting to start with. So end the end you're better off with > > return 1ull << (63 - clz64(value));
I intend to respin my own "[PATCH 0/2] Proactive pow2floor() fix, and dead code removal", and I'll keep your advice in mind for that.
