re PR tree-optimization/90240 (ICE in try_improve_iv_set, at tree-ssa-loop-ivopts...

re PR tree-optimization/90240 (ICE in try_improve_iv_set, at tree-ssa-loop-ivopts.c:6694)

	PR tree-optimization/90240
	* tree-ssa-loop-ivopts.c (get_scaled_computation_cost_at): Scale cost
	with respect to scaling factor pre-computed for each basic block.
	(try_improve_iv_set): Return bool if best_cost equals to iv_ca cost.
	(find_optimal_iv_set_1): Free iv_ca set if it has infinite_cost.
	(COST_SCALING_FACTOR_BOUND, determine_scaling_factor): New.
	(tree_ssa_iv_optimize_loop): Call determine_scaling_factor.  Extend
	live range for array of loop's basic blocks.  Cleanup aux field of
	loop's basic blocks.

	gcc/testsuite
	* gfortran.dg/graphite/pr90240.f: New test.

From-SVN: r271007