[Bug fortran/40168] missing unrolling/scalarization/reassoc/free

[rguenth at gcc dot gnu dot org]

------- 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