L.S., This code:
SUBROUTINE S(N) DIMENSION A(N), B(12) COMMON /COM/ B DO I = 1, 12 A(I) = B(I) ENDDO PRINT*,A(1:12) END when compiled thusly: $ gfortran -g -S -O3 -ftree-vectorize -ftree-vectorizer-verbose=2 -msse2 vect5.f draws the dreaded "unhandled data-ref" message: vect5.f:4: note: not vectorized: unhandled data-ref vect5.f:4: note: vectorized 0 loops in function. Hmmm, this is rather common (pun intended) in old Fortran code. Why is this style "punished" by not being vectorizable ;-) ? Kind regards, -- Toon Moene - e-mail: [EMAIL PROTECTED] - phone: +31 346 214290 Saturnushof 14, 3738 XG Maartensdijk, The Netherlands A maintainer of GNU Fortran 95: http://gcc.gnu.org/fortran/