On Thu, Mar 8, 2018 at 5:35 PM, Linus Torvalds <torva...@linux-foundation.org> wrote: > I don't want to weaken the type enforcement, and I _thought_ you had > done that __builtin_types_compatible_p() to keep it in place.
I thought so too (that originally came from Josh), but on removal, I was surprised that the checking was retained. :) > But if that's not why you did it, then why was it there at all? If the > type warning shows through even if it's in the other expression, then > just a > > > #define __min(t1, t2, x, y) \ > __builtin_choose_expr( \ > __builtin_constant_p(x) & \ > __builtin_constant_p(y), \ > (t1)(x) < (t2)(y) ? (t1)(x) : (t2)(y), \ > __single_eval_min(t1, t2, \ > ... > > would seem to be sufficient? > > Because logically, the only thing that matters is that x and y don't > have any side effects and can be evaluated twice, and > "__builtin_constant_p()" is already a much stronger version of that. > > Hmm? The __builtin_types_compatible_p() just doesn't seem to matter > for the only thing I thought it was there for. Yup, agreed. I'll drop it. -Kees -- Kees Cook Pixel Security
