On 05/04/2015 01:45 PM, Linus Torvalds wrote: > On Mon, May 4, 2015 at 1:33 PM, Richard Henderson <r...@redhat.com> wrote: >> >> A fair point. Though honestly, I was hoping that this feature would mostly >> be >> used for conditions that are "weird" -- that is, not normally describable by >> arithmetic at all. Otherwise, why are you using inline asm for it? > > I could easily imagine using some of the combinations for atomic operations. > > For example, doing a "lock decl", and wanting to see if the result is > negative or zero. Sure, it would be possible to set *two* booleans (ZF > and SF), but there's a contiional for "BE"..
Sure. I'd be more inclined to support these compound conditionals directly, rather than try to get the compiler to recognize them after the fact. Indeed, I believe we have a near complete set of them in the x86 backend already. It'd just be a matter of selecting the spellings for the constraints. r~
