(recombine_givs): Don't use a giv that's likely to be dead to derive others.

(recombine_givs): Don't use a giv that's likely to be dead to derive others.

	* (recombine_givs): Don't use a giv that's likely to be dead to
	derive others.
	* loop.c (recombine_givs): Fix test for lifetime overlaps / loop
	wrap around when deriving givs.

From-SVN: r24967