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
