A quick check with... gfortran -ffast-math -funroll-loops -msse3 -O3 -fgraphite-identity -ftree-vectorizer-verbose=2 air.f90 -o air >& air_cloog_legacy.txt grep "LOOP VECTORIZED" air_cloog_legacy.txt | wc -l 5
gfortran -ffast-math -funroll-loops -msse3 -O3 -fgraphite-identity -ftree-vectorizer-verbose=2 air.f90 -o air >& air_cloog_isl.txt grep "LOOP VECTORIZED" air_cloog_isl.txt | wc -l 5 ...for each build suggests that the 12% runtime performance penalty when using cloog-isl isn't due to missed vectorizations. Jack