------- Comment #5 from jv244 at cam dot ac dot uk 2007-03-02 18:15 ------- > > > > grid_fast.F:483: note: not vectorized: can't determine dependence between > > (*coef_447)[D.1967_2320] and (*coef_447)[D.1967_2320] > > DO icoef=1,coef_max > > coef(icoef,1)=coef(icoef,1)+alpha(icoef,lx)*g1 > > coef(icoef,2)=coef(icoef,2)+alpha(icoef,lx)*g2 > > coef(icoef,3)=coef(icoef,3)+alpha(icoef,lx)*g1k > > coef(icoef,4)=coef(icoef,4)+alpha(icoef,lx)*g2k > > ENDDO > > > > This part, which is in the default part of the switch statement should only be > executed in rare cases. I doubt it matters much in the overall timings. Also, > this loop has very short trips (i.e. coef_max should, for the provided input, > be at most 5).
I verified that the default branch is indeed not called frequently enough for this to matter. However, by deleting all other cases (equivalent, but specialized code), I can time that case, and find: gfortran: 6.636415 ifort: 5.252329 which means ifort is about 26% faster for the 'case default' branch. -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=31021
