On Wed, Nov 14, 2018 at 06:50:38PM +0300, Alexander Monakov wrote: > On Wed, 14 Nov 2018, Segher Boessenkool wrote: > > > I think with "=g" rather than "+g" this example is ok. > > > > No, it needs the register var as an input. That is the whole *point*. > > Hm. I think I see what you meant, but "+g" is not correct either: the > asm, by intent, depends *on the current value in the 'sp' hardreg*, not > *on the current value of some automatic variable that is supposed to be > passed on the 'sp' hardreg to the asm* (which is what expressed by the > input constraint).
Yeah, using local register vars to access global registers only works by accident. It does work currently though, and people apparently use it, so we shouldn't break it :-/ Segher
