2010-05-19 Christian Borntraeger <borntraeger@de.ibm.com>

2010-05-19  Christian Borntraeger  <borntraeger@de.ibm.com>

        * tree-ssa-loop-prefetch.c (mem_ref_group, ar_data): Change step
	to tree.
        (dump_mem_ref): Adopt debug code to handle a tree as step.  This
	also checks for a constant int vs.  non-constant but
	loop-invariant steps.
        (find_or_create_group): Change the sort algorithm to only consider
	steps that are constant ints.
        (idx_analyze_ref): Adopt code to handle a tree instead of a
	HOST_WIDE_INT for step.
        (gather_memory_references_ref): Handle tree instead of int and be
	prepared to see a NULL_TREE.
        (prune_ref_by_self_reuse, prune_ref_by_group_reuse): Do not prune
	prefetches if the step cannot be calculated at compile time.
        (issue_prefetch_ref): Issue prefetches for non-constant but
	loop-invariant steps.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@159557 138bc75d-0d04-0410-961f-82ee72b054a4