* gcse.c (struct expr:max_distance): New field.

	* gcse.c (struct expr:max_distance): New field.
	(doing_code_hoisting_p): New static variable.
	(want_to_gcse_p): Change signature.  Allow constrained hoisting of
	simple expressions, don't change behavior for PRE.  Set max_distance.
	(insert_expr_in_table): Set new max_distance field.
	(hash_scan_set): Update.
	(hoist_expr_reaches_here_p): Stop search after max_distance
	instructions.
	(find_occr_in_bb): New static function.  Use it in ...
	(hoist_code): Calculate sizes of basic block before any changes are
	done.  Pass max_distance to hoist_expr_reaches_here_p.
	(one_code_hoisting_pass): Set doing_code_hoisting_p.

	* params.def (PARAM_GCSE_COST_DISTANCE_RATIO,)
	(PARAM_GCSE_UNRESTRICTED_COST): New parameters.
	* params.h (GCSE_COST_DISTANCE_RATIO, GCSE_UNRESTRICTED_COST): New
	macros.
	* doc/invoke.texi (gcse-cost-distance-ratio, gcse-unrestricted-cost):
	Document.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@162589 138bc75d-0d04-0410-961f-82ee72b054a4