On Sun, Apr 08, 2007 at 11:37:43AM +0200, Uros Bizjak wrote: > H. J. Lu wrote: > > >>>inc/dec has the same performance as add/sub on Core 2 Duo. But > >>>inc/dec is shorter. > >>> > >>> > >>What about partial flag register dependency of inc/dec? > >> > > > >There is no partial flag register dependency on inc/dec. > > > > My docs say that "INC/DEC does not change the carry flag". But you have > better resources that I, so if you think that C2D should be left out of > X86_TUNE_USE_INCDEC, then the patch is pre-approved for mainline.
Partial flag register stall only applies to instructions like shift since they may shift by 0 in which case they won't change flag register. H.J.
