On Fri, Apr 24, 2009 at 01:34:37PM -0700, Andi Kleen wrote: > Robert Dewar <de...@adacore.com> writes: > > > Sebastian Pop wrote: > >> On Fri, Apr 24, 2009 at 08:12, Robert Dewar <de...@adacore.com> wrote: > >>>> What would we have to do to make PPL and CLooG required to build GCC? > >>> Why would that be desirable? Seems to me the current situation is > >>> clearly preferable. > >> To enable loop transforms in -O3. > > > > To me, you would have to show very clearly a significant performance > > gain for typical applications to justify the impact of adding > > PPL and CLooG. I don't see it. If you want these transformations > > you can get them, why go to all this disruptive effort for the > > default optimization case? > > I think his point was that they would be only widely used if they > were part of -O3 because likely most users are not willing to > set individual -f optimization flags.
Agreed. It might be a wise idea to include them in -O3 in 4.5, provided that we are confident by then that they are a consistent win. At that stage the libraries could be required.
