Richard Henderson <[EMAIL PROTECTED]> wrote on 20/06/2005 01:13:11: > On Sun, Jun 19, 2005 at 11:46:52PM +0300, Dorit Naishlos wrote: > > The thought was to supply an API that would let the vectorizer ask for the > > minimal capability it needs - if all we need is a vector shift of a > > constant value in bytes, lets ask exactly for that, so that targets that > > don't support non-constant shifts, or that support only byte shifts, could > > also enjoy this feature. > > Hmm. In theory we could get this information out of the predicates > on the expander, but it wouldn't be very clean. > > > A general vector shift that can take both constant and non-constant counts > > is indeed more general, and maybe what we prefer to have at the tree level. > > In this case, targets that can't tell the vectorizer that they can support > > general vector shifts, but could have told the vectorizer that they support > > an immediate vector shift, will just have to implement the REDUC_OP > > directly (using immediate vector shifts) in their machine description. > > At present I believe that most targets implement general shifts. I once worked on a DSP chip that didn't, but... > Lets > just go with that for now. As you say -- there's always a fallback > option available. > ...sure, I switched to general vec_shr/shl optabs thanks, dorit > > r~
