PR tree-optimization/81165
	* tree-ssa-threadupdate.c (uses_in_bb): New.
	(estimate_threading_killed_stmts): New.
	* tree-ssa-threadupdate.h (estimate_threading_killed_stmts): Prototype.
	* tree-ssa-threadedge.c
	(record_temporary_equivalences_from_stmts_at_dest): Expand limit
	when its hit.

	PR tree-optimization/81165
	* gcc.dg/pr81165.c: New.

From-SVN: r255724