10.2.7 Unswitching
LOOP FOR I := 1 TO 1000
IF (Test) THEN
X (I) := A(I) + B(I)
ELSE
X(I) := A(I) - B(I)
ENDLOOP
Here, the test is performed each time through the loop. The following performs the test once:
IF (Test) THEN
LOOP FOR I := 1 to 1000
X(I) = A(I) + B(I)
ENDLOOP
ELSE
LOOP FOR I := 1 to 100
X(I) = A(I) - B(I)
ENDLOOP
The second version here reduces the number of instructions executed,
but the code takes more space.