DFA and ppc?

[David Edelsohn]

>>>>> Jack Howarth writes:

Jack> In building g77 from the latest gcc 3.4 snapshot I noticed
Jack> that DFA is now being set up on ppc. Does anyone know how
Jack> functional this is currently on ppc? Also is the ppc DFA 
Jack> support specific to gcc 3.4 only or does it exist in the
Jack> gcc 3.3 that Apple will ship with Darwin 7.0/Panther? 

	Apple's GCC 3.3-based compiler uses the DFA scheduling model, but
it is not in the FSF release of GCC.

Jack> ps Are there supposed to be any particular improvements in
Jack> execution speed from switching to DFA or does it just
Jack> provide a more maintainable framwork to do instruction
Jack> scheduling? My brief benchmarking suggests that it doesn't
Jack> really do much for g77 at -O3 compared to stock gcc 3.3.2.

	There are numerous changes between GCC 3.3 and GCC 3.4, so I do
not know how you are testing that one change in isolation to compare just
the benefit of a DFA model.

David