http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47657
--- Comment #2 from Joost VandeVondele <Joost.VandeVondele at pci dot uzh.ch> 2011-02-09 11:25:42 UTC --- Created attachment 23283 --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=23283 testcase including timing routine, last number is flop rate. the cray compiler is supposed to *not* interchange loops, as I'm using: ftn -O3,ipa0,nointerchange,vector3 testcase.f90 to compile. This gives about 5.6Gflops. Unrolling still seems to happen (there are 16 mults in the inner loop), and ftn -O3,ipa0,nointerchange,vector3,unroll0 testcase.f90 yields poor performance (2.3Gflops). Gfortran 4.5 yields 3.424Gflops : gfortran -O3 -ffast-math -funroll-loops -march=native testcase.f90
