vect: Convert cost hooks to classes

vect: Convert cost hooks to classes

The current vector cost interface has a quite a bit of redundancy
built in.  Each target that defines its own hooks has to replicate
the basic unsigned[3] management.  Currently each target also
duplicates the cost adjustment for inner loops.

This patch instead defines a vector_costs class for holding
the scalar or vector cost and allows targets to subclass it.
There is then only one costing hook: to create a new costs
structure of the appropriate type.  Everything else can be
virtual functions, with common concepts implemented in the
base class rather than in each target's derivation.

This might seem like excess C++-ification, but it shaves
~100 LOC.  I've also got some follow-on changes that become
significantly easier with this patch.  Maybe it could help
with things like weighting blocks based on frequency too.

This will clash with Andre's unrolling patches.  His patches
have priority so this patch should queue behind them.

The x86 and rs6000 parts fully convert to a self-contained class.
The equivalent aarch64 changes are more complex, so this patch
just does the bare minimum.  A later patch will rework the
aarch64 bits.

gcc/
	* target.def (targetm.vectorize.init_cost): Replace with...
	(targetm.vectorize.create_costs): ...this.
	(targetm.vectorize.add_stmt_cost): Delete.
	(targetm.vectorize.finish_cost): Likewise.
	(targetm.vectorize.destroy_cost_data): Likewise.
	* doc/tm.texi.in (TARGET_VECTORIZE_INIT_COST): Replace with...
	(TARGET_VECTORIZE_CREATE_COSTS): ...this.
	(TARGET_VECTORIZE_ADD_STMT_COST): Delete.
	(TARGET_VECTORIZE_FINISH_COST): Likewise.
	(TARGET_VECTORIZE_DESTROY_COST_DATA): Likewise.
	* doc/tm.texi: Regenerate.
	* tree-vectorizer.h (vec_info::vec_info): Remove target_cost_data
	parameter.
	(vec_info::target_cost_data): Change from a void * to a vector_costs *.
	(vector_costs): New class.
	(init_cost): Take a vec_info and return a vector_costs.
	(dump_stmt_cost): Remove data parameter.
	(add_stmt_cost): Replace vinfo and data parameters with a vector_costs.
	(add_stmt_costs): Likewise.
	(finish_cost): Replace data parameter with a vector_costs.
	(destroy_cost_data): Delete.
	* tree-vectorizer.c (dump_stmt_cost): Remove data argument and
	don't print it.
	(vec_info::vec_info): Remove the target_cost_data parameter and
	initialize the member variable to null instead.
	(vec_info::~vec_info): Delete target_cost_data instead of calling
	destroy_cost_data.
	(vector_costs::add_stmt_cost): New function.
	(vector_costs::finish_cost): Likewise.
	(vector_costs::record_stmt_cost): Likewise.
	(vector_costs::adjust_cost_for_freq): Likewise.
	* tree-vect-loop.c (_loop_vec_info::_loop_vec_info): Update
	call to vec_info::vec_info.
	(vect_compute_single_scalar_iteration_cost): Update after above
	changes to costing interface.
	(vect_analyze_loop_operations): Likewise.
	(vect_estimate_min_profitable_iters): Likewise.
	(vect_analyze_loop_2): Initialize LOOP_VINFO_TARGET_COST_DATA
	at the start_over point, where it needs to be recreated after
	trying without slp.  Update retry code accordingly.
	* tree-vect-slp.c (_bb_vec_info::_bb_vec_info): Update call
	to vec_info::vec_info.
	(vect_slp_analyze_operation): Update after above changes to costing
	interface.
	(vect_bb_vectorization_profitable_p): Likewise.
	* targhooks.h (default_init_cost): Replace with...
	(default_vectorize_create_costs): ...this.
	(default_add_stmt_cost): Delete.
	(default_finish_cost, default_destroy_cost_data): Likewise.
	* targhooks.c (default_init_cost): Replace with...
	(default_vectorize_create_costs): ...this.
	(default_add_stmt_cost): Delete, moving logic to vector_costs instead.
	(default_finish_cost, default_destroy_cost_data): Delete.
	* config/aarch64/aarch64.c (aarch64_vector_costs): Inherit from
	vector_costs.  Add a constructor.
	(aarch64_init_cost): Replace with...
	(aarch64_vectorize_create_costs): ...this.
	(aarch64_add_stmt_cost): Replace with...
	(aarch64_vector_costs::add_stmt_cost): ...this.  Use record_stmt_cost
	to adjust the cost for inner loops.
	(aarch64_finish_cost): Replace with...
	(aarch64_vector_costs::finish_cost): ...this.
	(aarch64_destroy_cost_data): Delete.
	(TARGET_VECTORIZE_INIT_COST): Replace with...
	(TARGET_VECTORIZE_CREATE_COSTS): ...this.
	(TARGET_VECTORIZE_ADD_STMT_COST): Delete.
	(TARGET_VECTORIZE_FINISH_COST): Likewise.
	(TARGET_VECTORIZE_DESTROY_COST_DATA): Likewise.
	* config/i386/i386.c (ix86_vector_costs): New structure.
	(ix86_init_cost): Replace with...
	(ix86_vectorize_create_costs): ...this.
	(ix86_add_stmt_cost): Replace with...
	(ix86_vector_costs::add_stmt_cost): ...this.  Use adjust_cost_for_freq
	to adjust the cost for inner loops.
	(ix86_finish_cost, ix86_destroy_cost_data): Delete.
	(TARGET_VECTORIZE_INIT_COST): Replace with...
	(TARGET_VECTORIZE_CREATE_COSTS): ...this.
	(TARGET_VECTORIZE_ADD_STMT_COST): Delete.
	(TARGET_VECTORIZE_FINISH_COST): Likewise.
	(TARGET_VECTORIZE_DESTROY_COST_DATA): Likewise.
	* config/rs6000/rs6000.c (TARGET_VECTORIZE_INIT_COST): Replace with...
	(TARGET_VECTORIZE_CREATE_COSTS): ...this.
	(TARGET_VECTORIZE_ADD_STMT_COST): Delete.
	(TARGET_VECTORIZE_FINISH_COST): Likewise.
	(TARGET_VECTORIZE_DESTROY_COST_DATA): Likewise.
	(rs6000_cost_data): Inherit from vector_costs.
	Add a constructor.  Drop loop_info, cost and costing_for_scalar
	in favor of the corresponding vector_costs member variables.
	Add "m_" to the names of the remaining member variables and
	initialize them.
	(rs6000_density_test): Replace with...
	(rs6000_cost_data::density_test): ...this.
	(rs6000_init_cost): Replace with...
	(rs6000_vectorize_create_costs): ...this.
	(rs6000_update_target_cost_per_stmt): Replace with...
	(rs6000_cost_data::update_target_cost_per_stmt): ...this.
	(rs6000_add_stmt_cost): Replace with...
	(rs6000_cost_data::add_stmt_cost): ...this.  Use adjust_cost_for_freq
	to adjust the cost for inner loops.
	(rs6000_adjust_vect_cost_per_loop): Replace with...
	(rs6000_cost_data::adjust_vect_cost_per_loop): ...this.
	(rs6000_finish_cost): Replace with...
	(rs6000_cost_data::finish_cost): ...this.  Group loop code
	into a single if statement and pass the loop_vinfo down to
	subroutines.
	(rs6000_destroy_cost_data): Delete.