gcc/testsuite/algol68/execute/loop-14.a68

# { dg-options "-fstropping=upper" }  #
# The while-part shall not be elaborated if the iterator is exhausted.  #
BEGIN STRING s = "abc", INT j := 0;
      FOR i TO UPB s WHILE s[i] /= "x"
      DO j +:= 1 OD;
      ASSERT (j = 3)
END