KAP recognizes loops with invariant-IFs. To avoid repeatedly
performing the same IF test, KAP generates two versions of
the loop and places the IF test outside. This transformation
is enabled only when /scalaropt>2 . See the
command qualifiers /each_invariant_if_growth and
/max_invariant_if_growth for ways to restrict this
transformation.
DO 1 I=1,N IF (ADD) THEN X(I) = X(I) + Y(I) ELSE X(I) = X(I) - Y(I) ENDIF 1 CONTINUE 10 CONTINUE
Becomes:
IF (ADD) THEN DO 3 I=1,N X(I) = X(I) + Y(I) 3 CONTINUE ELSE DO 4 I=1,N X(I) = X(I) - Y(I) 4 CONTINUE ENDIF