r159163 - in /trunk/gcc: ChangeLog tree-ssa-loo...

[spop@gcc.gnu.org]

Author: spop
Date: Fri May  7 17:26:02 2010
New Revision: 159163

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=159163
Log:
Define the TRIP_COUNT_TO_AHEAD_RATIO heuristic.

2010-05-07  Changpeng Fang  <changpeng.fang@amd.com>

	* tree-ssa-loop-prefetch.c (TRIP_COUNT_TO_AHEAD_RATIO): New.
	(is_loop_prefetching_profitable): Do not insert prefetches
	when the trip count is not at least TRIP_COUNT_TO_AHEAD_RATIO
	times the prefetch ahead distance.

Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/tree-ssa-loop-prefetch.c