2010-05-25  Christian Borntraeger  <borntraeger@de.ibm.com>

	PR 44203
	* tree-ssa-loop-prefetch.c: Fix logic for step calculation to
	match the original (and intended) behaviour before r159557.  This
	changeset changed a=a+b*c to a=(a+b)*b which was obviously wrong
	in two ways.

From-SVN: r159816