On Thu, 2015-05-21 at 11:59 -0700, Richard Henderson wrote: > On 05/21/2015 11:44 AM, Segher Boessenkool wrote: > > On Thu, May 21, 2015 at 11:34:14AM -0700, Richard Henderson wrote: > >> Actually, I believe that the way CA is modeled at the moment is dangerous. > >> It's not a 64-bit value, but a 1-bit value. > > > > It's a fixed register and it is only ever set to 0 or 1. There are > > more targets that do such things, and it is safe. > > Old Cygnus proverb: Lie to the compiler and it will always bite you in the > end.
Just for the record, the same is being done on SH with the T bit. It's a fixed 1 bit hardreg, but declared and treated as SImode, because all the other integer arithmetic is done primarily in SImode, too. No significant problems with that. Cheers, Oleg
