setge/le/uge/ule selected by themselves require an xori with 1.
If we're negating the setcc, we can fold the xori with the neg
to create an addi with -1.
This works because xori X, 1 is equivalent to 1 - X if X is either
0 or 1. So we're doing -(1 - X) which is X-1 or X+-1.
This improves the code for selecting between 0 and -1 based on a
condition for some conditions.
It would be good to add a comment here that expresses some of the same information used in the patch description, explaining why this pattern is valid.