------- Comment #5 from rguenth at gcc dot gnu dot org 2009-05-16 11:20 -------
With that patch and
-O3 -ffast-math -funroll-loops -mfpmath=sse -msse2 --param
max-completely-peel-times=27 --param max-completely-peeled-insns=1500
--params for allow unrolling of all innermost loops I get
./test
Sparse: time[s] 0.68804300
New: time[s] 0.40802497
speedup 1.6862767
Glfops 1.5881380
Error: 1.11022302462515654E-016
which isn't too bad. The rest of the difference might be attributed to
unfortunate scheduling or that multiplication thing (PRE skips a lot
of multiplication hoisting opportunities because they look like
induction variables though LIM later hoists them).
With the above flags and -fno-ivopts (looking what dump stuff it does
again...) I get
./test
Sparse: time[s] 0.58003598
New: time[s] 0.62803900
speedup 0.92356682
Glfops 1.0317831
Error: 1.11022302462515654E-016
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=40168
