2011-08-26 Zdenek Dvorak <ook@ucw.cz>
Tom de Vries <tom@codesourcery.com>
* tree-ssa-loop-ivopts.c (struct cost_pair): Add comp field.
(struct ivopts_data): Add loop_single_exit_p field.
(niter_for_exit): Change parameter desc_p into return value. Return
desc if desc->may_be_zero. Free desc if unused.
(niter_for_single_dom_exit): Change return type.
(find_induction_variables): Handle changed return type of
niter_for_single_dom_exit. Dump may_be_zero.
(add_candidate_1): Keep original base and step type for IP_ORIGINAL.
(set_use_iv_cost): Add and handle comp parameter.
(determine_use_iv_cost_generic, determine_use_iv_cost_address): Add
comp argument to set_use_iv_cost.
(strip_wrap_conserving_type_conversions, expr_equal_p)
(difference_cannot_overflow_p, iv_elimination_compare_lt): New function.
(may_eliminate_iv): Add comp parameter. Handle new return type of
niter_for_exit. Use loop_single_exit_p. Use iv_elimination_compare_lt.
(determine_use_iv_cost_condition): Add comp argument to set_use_iv_cost
and may_eliminate_iv.
(rewrite_use_compare): Move call to iv_elimination_compare to ...
(may_eliminate_iv): Here.
(tree_ssa_iv_optimize_loop): Initialize loop_single_exit_p.
Co-Authored-By: Tom de Vries <tom@codesourcery.com>
From-SVN: r178104
