re PR middle-end/42505 (loop canonicalization causes a lot of unnecessary temporary...

re PR middle-end/42505 (loop canonicalization causes a lot of unnecessary temporary variables)

2010-07-05  Sandra Loosemore  <sandra@codesourcery.com>

	PR middle-end/42505

	gcc/
	* tree-ssa-loop-ivopts.c (determine_set_costs): Delete obsolete
	comments about cost model.
	(try_add_cand_for):  Add second strategy for choosing initial set
	based on original IVs, controlled by ORIGINALP argument.
	(get_initial_solution): Add ORIGINALP argument.
	(find_optimal_iv_set_1): New function, split from find_optimal_iv_set.
	(find_optimal_iv_set): Try two different strategies for choosing
	the IV set, and return the one with lower cost.

	gcc/testsuite/
	* gcc.target/arm/pr42505.c: New test case.

From-SVN: r161844