2007-07-30  Sandra Loosemore  <sandra@codesourcery.com>
	    David Ung  <davidu@mips.com>
            Nigel Stephens <nigel@mips.com>

	gcc/
	Add hooks for back-end reset on per-function basis.

	* target-def.h (TARGET_PREPARE_FUNCTION_START): Define.
	(TARGET_END_OF_FILE_CLEANUP): Define
	(TARGET_INITIALIZER):  Add entries for above symbols.
	* target.h (struct gcc_target):  Add prepare_function_start
	and end_of_file_cleanup slots.
	* doc/tm.texi (TARGET_PREPARE_FUNCTION_START): Document.
	(TARGET_END_OF_FILE_CLEANUP): Likewise.

	* function.c (prepare_function_start): Invoke prepare_function_start
	target hook.
	* toplev.c (compile_file): Invoke end_of_file_cleanup target hook.
	(init_alignments): New, split out from...
	(process_options): ...here.
	(backend_init_target):  New, split out from...
	(backend_init): ...here.
	(lang_dependent_init_target):  New, split out from...
	(lang_dependent_init): ...here.
	(target_reinit): New.
	* toplev.h (target_reinit): Declare.
	* cfgloopanal.c (init_set_costs): Explicitly zero target_avail_regs.
	* expr.c (init_expr_target): Renamed from init_expr_once, since it
	now can be called more than once.  Update comments.
	* expr.h (init_expr_target): Likewise.
	* alias.c (init_alias_target): Renamed from init_alias_once, since it
	now can be called more than once.  Explicitly zero
	static_reg_base_value.
	* emit-rtl.c (init_emit_regs): New, split out from...
	(init_emit_once): Here.
	* regclass.c (initial_fixed_regs, initial_call_used_regs): Make
	non-const, so that changes from command-line arguments can overwrite
	values provided by the static initializers.
	(initial_call_really_used_regs): New, used similarly to the above.
	(last_mode_for_init_move_cost): Promoted function-local static to
	file-scope static to make it accessible outside init_move_cost.
	(init_reg_sets): Do not initialize fixed_regs and call_used_regs yet.
	Do not initialize inv_reg_alloc_order yet, either.
	(init_move_cost): Use last_mode_for_init_move_cost instead of
	function-local static.
	(init_reg_sets_1): Initialize fixed_regs, call_used_regs, and
	call_really_used_regs now.  Also initialize inv_reg_alloc_order.
	Zero reg_class_subunion and reg_class_superunion.
	Clear losing_caller_save_reg_set.  Preserve global registers if
	called more than once.  Reset move cost, may_move_in_cost,
	may_move_out_cost, and last_mode_for_init_move_cost.
	(init_reg_modes_target): Renamed from init_reg_modes_once, since it
	can now be invoked more than once.  Update comments.
	(init_regs): Update comments.
	(fix_register): Update initial_fixed_regs, initial_call_used_regs,
	and initial_call_really_used_regs, instead of the non-initial 
        variables.  This allows us to save the command-line register settings
	after target reinitialization.
	(init_reg_autoinc): Zero forbidden_inc_dec_classes.
	* rtl.h (init_emit_regs): Declare.
	(init_reg_modes_target, init_alias_target): Renamed as described
	above.
	* reload1.c (init_reload): Update comments.