Patch to fix ICE with -fprefetch-loop-arrays

[Steve Ellcey]

This is a ping on my patch to fix PR tree-optimization/32087
which is an ICE with prefetching on IA64 (Linux and HP-UX).

Richard Guenther had a question about it and I addressed that (or tried
to) in a reply but I haven't gotten any more feedback.

Original mail with patch is at:

	http://gcc.gnu.org/ml/gcc-patches/2007-06/msg00357.html

Steve Ellcey
sje@cup.hp.com