gcc/testsuite/algol68/execute/abs-bits-1.a68

# { dg-options "-fstropping=upper" }  #
# ABS for SIZETY BITS #
BEGIN ASSERT (255 = ABS 16rff);
      ASSERT (LONG 255 = ABS LONG 16rff);
      ASSERT (LONG LONG 255 = ABS LONG LONG 16rff)
      # XXX test ABS of negative numbers (extension).  #
END